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Sample records for accuracy results showed

  1. Children's school-breakfast reports and school-lunch reports (in 24-h dietary recalls): conventional and reporting-error-sensitive measures show inconsistent accuracy results for retention interval and breakfast location.

    PubMed

    Baxter, Suzanne D; Guinn, Caroline H; Smith, Albert F; Hitchcock, David B; Royer, Julie A; Puryear, Megan P; Collins, Kathleen L; Smith, Alyssa L

    2016-04-14

    Validation-study data were analysed to investigate retention interval (RI) and prompt effects on the accuracy of fourth-grade children's reports of school-breakfast and school-lunch (in 24-h recalls), and the accuracy of school-breakfast reports by breakfast location (classroom; cafeteria). Randomly selected fourth-grade children at ten schools in four districts were observed eating school-provided breakfast and lunch, and were interviewed under one of eight conditions created by crossing two RIs ('short'--prior-24-hour recall obtained in the afternoon and 'long'--previous-day recall obtained in the morning) with four prompts ('forward'--distant to recent, 'meal name'--breakfast, etc., 'open'--no instructions, and 'reverse'--recent to distant). Each condition had sixty children (half were girls). Of 480 children, 355 and 409 reported meals satisfying criteria for reports of school-breakfast and school-lunch, respectively. For breakfast and lunch separately, a conventional measure--report rate--and reporting-error-sensitive measures--correspondence rate and inflation ratio--were calculated for energy per meal-reporting child. Correspondence rate and inflation ratio--but not report rate--showed better accuracy for school-breakfast and school-lunch reports with the short RI than with the long RI; this pattern was not found for some prompts for each sex. Correspondence rate and inflation ratio showed better school-breakfast report accuracy for the classroom than for cafeteria location for each prompt, but report rate showed the opposite. For each RI, correspondence rate and inflation ratio showed better accuracy for lunch than for breakfast, but report rate showed the opposite. When choosing RI and prompts for recalls, researchers and practitioners should select a short RI to maximise accuracy. Recommendations for prompt selections are less clear. As report rates distort validation-study accuracy conclusions, reporting-error-sensitive measures are recommended.

  2. Accuracy of results with NASTRAN modal synthesis

    NASA Technical Reports Server (NTRS)

    Herting, D. N.

    1978-01-01

    A new method for component mode synthesis was developed for installation in NASTRAN level 17.5. Results obtained from the new method are presented, and these results are compared with existing modal synthesis methods.

  3. Establishing precision and accuracy in PDV results

    SciTech Connect

    Briggs, Matthew E.; Howard, Marylesa; Diaz, Abel

    2016-04-19

    We need to know uncertainties and systematic errors because we create and compare against archival weapons data, we constrain the models, and we provide scientific results. Good estimates of precision from the data record are available and should be incorporated into existing results; reanalysis of valuable data is suggested. Estimates of systematic errors are largely absent. The original work by Jensen et al. using gun shots for window corrections, and the integrated velocity comparison with X-rays by Schultz are two examples where any systematic errors appear to be <1% level.

  4. "Certified" Laboratory Practitioners and the Accuracy of Laboratory Test Results.

    ERIC Educational Resources Information Center

    Boe, Gerard P.; Fidler, James R.

    1988-01-01

    An attempt to replicate a study of the accuracy of test results of medical laboratories was unsuccessful. Limitations of the obtained data prevented the research from having satisfactory internal validity, so no formal report was published. External validity of the study was also limited because the systematic random sample of 78 licensed…

  5. Alzheimer's disease and memory-monitoring impairment: Alzheimer's patients show a monitoring deficit that is greater than their accuracy deficit.

    PubMed

    Dodson, Chad S; Spaniol, Maggie; O'Connor, Maureen K; Deason, Rebecca G; Ally, Brandon A; Budson, Andrew E

    2011-07-01

    We assessed the ability of two groups of patients with mild Alzheimer's disease (AD) and two groups of older adults to monitor the likely accuracy of recognition judgments and source identification judgments about who spoke something earlier. Alzheimer's patients showed worse performance on both memory judgments and were less able to monitor with confidence ratings the likely accuracy of both kinds of memory judgments, as compared to a group of older adults who experienced the identical study and test conditions. Critically, however, when memory performance was made comparable between the AD patients and the older adults (e.g., by giving AD patients extra exposures to the study materials), AD patients were still greatly impaired at monitoring the likely accuracy of their recognition and source judgments. This result indicates that the monitoring impairment in AD patients is actually worse than their memory impairment, as otherwise there would have been no differences between the two groups in monitoring performance when there were no differences in accuracy. We discuss the brain correlates of this memory-monitoring deficit and also propose a Remembrance-Evaluation model of memory-monitoring.

  6. 13. DETAIL VIEW OF BUTTRESS 4 SHOWING THE RESULTS OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. DETAIL VIEW OF BUTTRESS 4 SHOWING THE RESULTS OF POOR CONSTRUCTION WORK. THOUGH NOT A SERIOUS STRUCTURAL DEFICIENCY, THE 'HONEYCOMB' TEXTURE OF THE CONCRETE SURFACE WAS THE RESULT OF INADEQUATE TAMPING AT THE TIME OF THE INITIAL 'POUR'. - Hume Lake Dam, Sequioa National Forest, Hume, Fresno County, CA

  7. Expression of CRM1 and CDK5 shows high prognostic accuracy for gastric cancer

    PubMed Central

    Sun, Yu-Qin; Xie, Jian-Wei; Xie, Hong-Teng; Chen, Peng-Chen; Zhang, Xiu-Li; Zheng, Chao-Hui; Li, Ping; Wang, Jia-Bin; Lin, Jian-Xian; Cao, Long-Long; Huang, Chang-Ming; Lin, Yao

    2017-01-01

    AIM To evaluate the predictive value of the expression of chromosomal maintenance (CRM)1 and cyclin-dependent kinase (CDK)5 in gastric cancer (GC) patients after gastrectomy. METHODS A total of 240 GC patients who received standard gastrectomy were enrolled in the study. The expression level of CRM1 and CDK5 was detected by immunohistochemistry. The correlations between CRM1 and CDK5 expression and clinicopathological factors were explored. Univariate and multivariate survival analyses were used to identify prognostic factors for GC. Receiver operating characteristic analysis was used to compare the accuracy of the prediction of clinical outcome by the parameters. RESULTS The expression of CRM1 was significantly related to size of primary tumor (P = 0.005), Borrmann type (P = 0.006), degree of differentiation (P = 0.004), depth of invasion (P = 0.008), lymph node metastasis (P = 0.013), TNM stage (P = 0.002) and distant metastasis (P = 0.015). The expression of CDK5 was significantly related to sex (P = 0.048) and Lauren’s classification (P = 0.011). Multivariate Cox regression analysis identified that CRM1 and CDK5 co-expression status was an independent prognostic factor for overall survival (OS) of patients with GC. Integration of CRM1 and CDK5 expression could provide additional prognostic value for OS compared with CRM1 or CDK5 expression alone (P = 0.001). CONCLUSION CRM1 and CDK5 co-expression was an independent prognostic factors for GC. Combined CRM1 and CDK5 expression could provide a prognostic model for OS of GC. PMID:28373767

  8. Results on fibre scrambling for high accuracy radial velocity measurements

    NASA Astrophysics Data System (ADS)

    Avila, Gerardo; Singh, Paul; Chazelas, Bruno

    2010-07-01

    We present in this paper experimental data on fibres and scramblers to increase the photometrical stability of the spectrograph PSF. We have used round, square, octagonal fibres and beam homogenizers. This study is aimed to enhance the accuracy measurements of the radial velocities for ESO ESPRESSO (VLT) and CODEX (E-ELT) instruments.

  9. Poor Metacomprehension Accuracy as a Result of Inappropriate Cue Use

    ERIC Educational Resources Information Center

    Thiede, Keith W.; Griffin, Thomas D.; Wiley, Jennifer; Anderson, Mary C. M.

    2010-01-01

    Two studies attempt to determine the causes of poor metacomprehension accuracy and then, in turn, to identify interventions that circumvent these difficulties to support effective comprehension monitoring performance. The first study explored the cues that both at-risk and typical college readers use as a basis for their metacomprehension…

  10. Estimated results analysis and application of the precise point positioning based high-accuracy ionosphere delay

    NASA Astrophysics Data System (ADS)

    Wang, Shi-tai; Peng, Jun-huan

    2015-12-01

    The characterization of ionosphere delay estimated with precise point positioning is analyzed in this paper. The estimation, interpolation and application of the ionosphere delay are studied based on the processing of 24-h data from 5 observation stations. The results show that the estimated ionosphere delay is affected by the hardware delay bias from receiver so that there is a difference between the estimated and interpolated results. The results also show that the RMSs (root mean squares) are bigger, while the STDs (standard deviations) are better than 0.11 m. When the satellite difference is used, the hardware delay bias can be canceled. The interpolated satellite-differenced ionosphere delay is better than 0.11 m. Although there is a difference between the between the estimated and interpolated ionosphere delay results it cannot affect its application in single-frequency positioning and the positioning accuracy can reach cm level.

  11. Results of a remote multiplexer/digitizer unit accuracy and environmental study

    NASA Technical Reports Server (NTRS)

    Wilner, D. O.

    1977-01-01

    A remote multiplexer/digitizer unit (RMDU), a part of the airborne integrated flight test data system, was subjected to an accuracy study. The study was designed to show the effects of temperature, altitude, and vibration on the RMDU. The RMDU was subjected to tests at temperatures from -54 C (-65 F) to 71 C (160 F), and the resulting data are presented here, along with a complete analysis of the effects. The methods and means used for obtaining correctable data and correcting the data are also discussed.

  12. Meta-GWAS Accuracy and Power (MetaGAP) Calculator Shows that Hiding Heritability Is Partially Due to Imperfect Genetic Correlations across Studies

    PubMed Central

    Rietveld, Cornelius A.; Johannesson, Magnus; Magnusson, Patrik K. E.; Uitterlinden, André G.; van Rooij, Frank J. A.; Hofman, Albert

    2017-01-01

    Large-scale genome-wide association results are typically obtained from a fixed-effects meta-analysis of GWAS summary statistics from multiple studies spanning different regions and/or time periods. This approach averages the estimated effects of genetic variants across studies. In case genetic effects are heterogeneous across studies, the statistical power of a GWAS and the predictive accuracy of polygenic scores are attenuated, contributing to the so-called ‘missing heritability’. Here, we describe the online Meta-GWAS Accuracy and Power (MetaGAP) calculator (available at www.devlaming.eu) which quantifies this attenuation based on a novel multi-study framework. By means of simulation studies, we show that under a wide range of genetic architectures, the statistical power and predictive accuracy provided by this calculator are accurate. We compare the predictions from the MetaGAP calculator with actual results obtained in the GWAS literature. Specifically, we use genomic-relatedness-matrix restricted maximum likelihood to estimate the SNP heritability and cross-study genetic correlation of height, BMI, years of education, and self-rated health in three large samples. These estimates are used as input parameters for the MetaGAP calculator. Results from the calculator suggest that cross-study heterogeneity has led to attenuation of statistical power and predictive accuracy in recent large-scale GWAS efforts on these traits (e.g., for years of education, we estimate a relative loss of 51–62% in the number of genome-wide significant loci and a relative loss in polygenic score R2 of 36–38%). Hence, cross-study heterogeneity contributes to the missing heritability. PMID:28095416

  13. Geopositioning accuracy prediction results for registration of imaging and nonimaging sensors using moving objects

    NASA Astrophysics Data System (ADS)

    Taylor, Charles R.; Dolloff, John T.; Lofy, Brian A.; Luker, Steve A.

    2003-08-01

    BAE SYSTEMS is developing a "4D Registration" capability for DARPA's Dynamic Tactical Targeting program. This will further advance our automatic image registration capability to use moving objects for image registration, and extend our current capability to include the registration of non-imaging sensors. Moving objects produce signals that are identifiable across multiple sensors such as radar moving target indicators, unattended ground sensors, and imaging sensors. Correspondences of those signals across sensor types make it possible to improve the support data accuracy for each of the sensors involved in the correspondence. The amount of accuracy improvement possible, and the effects of the accuracy improvement on geopositioning with the sensors, is a complex problem. The main factors that contribute to the complexity are the sensor-to-target geometry, the a priori sensor support data accuracy, sensor measurement accuracy, the distribution of identified objects in ground space, and the motion and motion uncertainty of the identified objects. As part of the 4D Registration effort, BAE SYSTEMS is conducting a sensitivity study to investigate the complexities and benefits of multisensor registration with moving objects. The results of the study will be summarized.

  14. Accuracy and stability of positioning in radiosurgery: Long term results of the Gamma Knife system

    SciTech Connect

    Heck, Bernhard; Jess-Hempen, Anja; Kreiner, Hans Juerg; Schoepgens, Hans; Mack, Andreas

    2007-04-15

    The primary aim of this investigation was to determine the long term overall accuracy of an irradiation position of Gamma Knife systems. The mechanical accuracy of the system as well as the overall accuracy of an irradiation position was examined by irradiating radiosensitive films. To measure the mechanical accuracy, the GafChromic registered film was fixed by a special tool at the unit center point (UCP). For overall accuracy the film was mounted inside a phantom at a target position given by a two-dimensional cross. Its position was determined by CT or MRI scans, a treatment was planned to hit this target by use of the standard planning software and the radiation was finally delivered. This procedure is named ''system test'' according to DIN 6875-1 and is equivalent to a treatment simulation. The used GafChromic registered films were evaluated by high resolution densitometric measurements. The Munich Gamma Knife UCP coincided within x;y;z: -0.014{+-}0.09 mm; 0.013{+-}0.09 mm; -0.002{+-}0.06 mm (mean{+-}SD) to the center of dose distribution. There was no trend in the measured data observed over more than ten years. All measured data were within a sphere of 0.2 mm radius. When basing the target definition in the system test on MRI scans, we obtained an overall accuracy of an irradiation position in the x direction of 0.21{+-}0.32 mm and in the y direction 0.15{+-}0.26 mm (mean{+-}SD). When a CT-based target definition was used, we measured distances in x direction 0.06{+-}0.09 mm and in y direction 0.04{+-}0.09 mm (mean{+-}SD), respectively. These results were compared with those obtained with a Gamma Knife equipped with an automatic positioning system (APS) by use of a different phantom. This phantom was found to be slightly less accurate due to its mechanical construction and the soft fixation into the frame. The phantom related position deviation was found to be about {+-}0.2 mm, and therefore the measured accuracy of the APS Gamma Knife was evidently less

  15. How well do people recall risk factor test results? Accuracy and bias among cholesterol screening participants.

    PubMed

    Croyle, Robert T; Loftus, Elizabeth F; Barger, Steven D; Sun, Yi-Chun; Hart, Marybeth; Gettig, JoAnn

    2006-05-01

    The authors conducted a community-based cholesterol screening study to examine accuracy of recall for self-relevant health information in long-term autobiographical memory. Adult community residents (N = 496) were recruited to participate in a laboratory-based cholesterol screening and were also provided cholesterol counseling in accordance with national guidelines. Participants were subsequently interviewed 1, 3, or 6 months later to assess their memory for their test results. Participants recalled their exact cholesterol levels inaccurately (38.0% correct) but their cardiovascular risk category comparatively well (88.7% correct). Recall errors showed a systematic bias: Individuals who received the most undesirable test results were most likely to remember their cholesterol scores and cardiovascular risk categories as lower (i.e., healthier) than those actually received. Recall bias was unrelated to age, education, knowledge, self-rated health status, and self-reported efforts to reduce cholesterol. The findings provide evidence that recall of self-relevant health information is susceptible to self-enhancement bias.

  16. First experimental results of very high accuracy centroiding measurements for the neat astrometric mission

    NASA Astrophysics Data System (ADS)

    Crouzier, A.; Malbet, F.; Preis, O.; Henault, F.; Kern, P.; Martin, G.; Feautrier, P.; Stadler, E.; Lafrasse, S.; Delboulbé, A.; Behar, E.; Saint-Pe, M.; Dupont, J.; Potin, S.; Cara, C.; Donati, M.; Doumayrou, E.; Lagage, P. O.; Léger, A.; LeDuigou, J. M.; Shao, M.; Goullioud, R.

    2013-09-01

    NEAT is an astrometric mission proposed to ESA with the objectives of detecting Earth-like exoplanets in the habitable zone of nearby solar-type stars. NEAT requires the capability to measure stellar centroids at the precision of 5e-6 pixel. Current state-of-the-art methods for centroid estimation have reached a precision of about 2e-5 pixel at two times Nyquist sampling, this was shown at the JPL by the VESTA experiment. A metrology system was used to calibrate intra and inter pixel quantum efficiency variations in order to correct pixelation errors. The European part of the NEAT consortium is building a testbed in vacuum in order to achieve 5e-6 pixel precision for the centroid estimation. The goal is to provide a proof of concept for the precision requirement of the NEAT spacecraft. In this paper we present the metrology and the pseudo stellar sources sub-systems, we present a performance model and an error budget of the experiment and we report the present status of the demonstration. Finally we also present our first results: the experiment had its first light in July 2013 and a first set of data was taken in air. The analysis of this first set of data showed that we can already measure the pixel positions with an accuracy of about 1e-4 pixel.

  17. Creating a Standard Set of Metrics to Assess Accuracy of Solar Forecasts: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Banunarayanan, V.; Brockway, A.; Marquis, M.; Haupt, S. E.; Brown, B.; Fowler, T.; Jensen, T.; Hamann, H.; Lu, S.; Hodge, B.; Zhang, J.; Florita, A.

    2013-12-01

    The U.S. Department of Energy (DOE) SunShot Initiative, launched in 2011, seeks to reduce the cost of solar energy systems by 75% from 2010 to 2020. In support of the SunShot Initiative, the DOE Office of Energy Efficiency and Renewable Energy (EERE) is partnering with the National Oceanic and Atmospheric Administration (NOAA) and solar energy stakeholders to improve solar forecasting. Through a funding opportunity announcement issued in the April, 2012, DOE is funding two teams - led by National Center for Atmospheric Research (NCAR), and by IBM - to perform three key activities in order to improve solar forecasts. The teams will: (1) With DOE and NOAA's leadership and significant stakeholder input, develop a standardized set of metrics to evaluate forecast accuracy, and determine the baseline and target values for these metrics; (2) Conduct research that yields a transformational improvement in weather models and methods for forecasting solar irradiance and power; and (3) Incorporate solar forecasts into the system operations of the electric power grid, and evaluate the impact of forecast accuracy on the economics and reliability of operations using the defined, standard metrics. This paper will present preliminary results on the first activity: the development of a standardized set of metrics, baselines and target values. The results will include a proposed framework for metrics development, key categories of metrics, descriptions of each of the proposed set of specific metrics to measure forecast accuracy, feedback gathered from a range of stakeholders on the metrics, and processes to determine baselines and target values for each metric. The paper will also analyze the temporal and spatial resolutions under which these metrics would apply, and conclude with a summary of the work in progress on solar forecasting activities funded by DOE.

  18. The results of the campaign for evaluating sphygmomanometers accuracy and their physical conditions

    PubMed

    Mion; Pierin; Alavarce; Vasconcellos

    2000-01-01

    OBJECTIVE: To evaluate the sphygmomanometers calibration accuracy and the physical conditions of the cuff-bladder, bulb, pump, and valve. METHODS: Sixty hundred and forty five aneroid sphygmomanometers were evaluated, 521 used in private practice and 124 used in hospitals. Aneroid manometers were tested against a properly calibrated mercury manometer and were considered calibrated when the error was < or = 3 mm Hg. The physical conditions of the cuffs-bladder, bulb, pump, and valve were also evaluated. RESULTS: Of the aneroid sphygmomanometers tested, 51% of those used in private practice and 56% of those used in hospitals were found to be not accurately calibrated. Of these, the magnitude of inaccuracy ranged from 4 to 8 mm Hg in 70% and 51% of the devices, respectively. The problems found in the cuffs--bladders, bulbs, pumps, and valves of the private practice and hospital devices were bladder damage (34% vs. 21%, respectively), holes/leaks in the bulbs (22% vs. 4%, respectively), and rubber aging (15% vs. 12%, respectively). Of the devices tested, 72% revealed at least one problem interfering with blood pressure measurement accuracy. CONCLUSION: Most of the manometers evaluated, whether used in private practice or in hospitals, were found to be inaccurate and unreliable, and their use may jeopardize the diagnosis and treatment of arterial hypertension.

  19. The results of the Campaign for evaluating sphygmomanometers accuracy and their physical conditions.

    PubMed

    Mion; Pierin; Alavarce; Vasconcellos

    2000-01-01

    OBJECTIVE: To evaluate the sphygmomanometers calibration accuracy and the physical conditions of the cuff-bladder, bulb, pump, and valve. METHODS: Sixty hundred and forty five aneroid sphygmomanometers were evaluated, 521 used in private practice and 124 used in hospitals. Aneroid manometers were tested against a properly calibrated mercury manometer and were considered calibrated when the error was RESULTS: Of the aneroid sphygmomanometers tested, 51% of those used in private practice and 56% of those used in hospitals were found to be not accurately calibrated. Of these, the magnitude of inaccuracy ranged from 4 to 8mm Hg in 70% and 51% of the devices, respectively. The problems found in the cuffs - bladders, bulbs, pumps, and valves of the private practice and hospital devices were bladder damage (34% vs. 21%, respectively), holes/leaks in the bulbs (22% vs. 4%, respectively), and rubber aging (15% vs. 12%, respectively). Of the devices tested, 72% revealed at least one problem interfering with blood pressure measurement accuracy. CONCLUSION: Most of the manometers evaluated, whether used in private practice or in hospitals, were found to be inaccurate and unreliable, and their use may jeopardize the diagnosis and treatment of arterial hypertension.

  20. Results of 17 Independent Geopositional Accuracy Assessments of Earth Satellite Corporation's GeoCover Landsat Thematic Mapper Imagery. Geopositional Accuracy Validation of Orthorectified Landsat TM Imagery: Northeast Asia

    NASA Technical Reports Server (NTRS)

    Smith, Charles M.

    2003-01-01

    This report provides results of an independent assessment of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover, Orthorectified Landsat Thematic Mapper (TM) imagery over Northeast Asia. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.

  1. Summarising and validating test accuracy results across multiple studies for use in clinical practice.

    PubMed

    Riley, Richard D; Ahmed, Ikhlaaq; Debray, Thomas P A; Willis, Brian H; Noordzij, J Pieter; Higgins, Julian P T; Deeks, Jonathan J

    2015-06-15

    Following a meta-analysis of test accuracy studies, the translation of summary results into clinical practice is potentially problematic. The sensitivity, specificity and positive (PPV) and negative (NPV) predictive values of a test may differ substantially from the average meta-analysis findings, because of heterogeneity. Clinicians thus need more guidance: given the meta-analysis, is a test likely to be useful in new populations, and if so, how should test results inform the probability of existing disease (for a diagnostic test) or future adverse outcome (for a prognostic test)? We propose ways to address this. Firstly, following a meta-analysis, we suggest deriving prediction intervals and probability statements about the potential accuracy of a test in a new population. Secondly, we suggest strategies on how clinicians should derive post-test probabilities (PPV and NPV) in a new population based on existing meta-analysis results and propose a cross-validation approach for examining and comparing their calibration performance. Application is made to two clinical examples. In the first example, the joint probability that both sensitivity and specificity will be >80% in a new population is just 0.19, because of a low sensitivity. However, the summary PPV of 0.97 is high and calibrates well in new populations, with a probability of 0.78 that the true PPV will be at least 0.95. In the second example, post-test probabilities calibrate better when tailored to the prevalence in the new population, with cross-validation revealing a probability of 0.97 that the observed NPV will be within 10% of the predicted NPV.

  2. Gun shows and gun violence: fatally flawed study yields misleading results.

    PubMed

    Wintemute, Garen J; Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A

    2010-10-01

    A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled "The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas" outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors' prior research. The study should not be used as evidence in formulating gun policy.

  3. Accuracy of relative positioning by interferometry with GPS Double-blind test results

    NASA Technical Reports Server (NTRS)

    Counselman, C. C., III; Gourevitch, S. A.; Herring, T. A.; King, B. W.; Shapiro, I. I.; Cappallo, R. J.; Rogers, A. E. E.; Whitney, A. R.; Greenspan, R. L.; Snyder, R. E.

    1983-01-01

    MITES (Miniature Interferometer Terminals for Earth Surveying) observations conducted on December 17 and 29, 1980, are analyzed. It is noted that the time span of the observations used on each day was 78 minutes, during which five satellites were always above 20 deg elevation. The observations are analyzed to determine the intersite position vectors by means of the algorithm described by Couselman and Gourevitch (1981). The average of the MITES results from the two days is presented. The rms differences between the two determinations of the components of the three vectors, which were about 65, 92, and 124 m long, were 8 mm for the north, 3 mm for the east, and 6 mm for the vertical. It is concluded that, at least for short distances, relative positioning by interferometry with GPS can be done reliably with subcentimeter accuracy.

  4. Astronomy Diagnostic Test Results Reflect Course Goals and Show Room for Improvement

    NASA Astrophysics Data System (ADS)

    Lopresto, Michael C.

    The results of administering the Astronomy Diagnostic Test (ADT) to introductory astronomy students at Henry Ford Community College over three years have shown gains comparable with national averages. Results have also accurately corresponded to course goals, showing greater gains in topics covered in more detail, and lower gains in topics covered in less detail. Also evident in the results were topics for which improvement of instruction is needed. These factors and the ease with which the ADT can be administered constitute evidence of the usefulness of the ADT as an assessment instrument for introductory astronomy.

  5. Results of the 2015 Spitzer Exoplanet Data Challenge: Repeatability and Accuracy of Exoplanet Eclipse Depths

    NASA Astrophysics Data System (ADS)

    Ingalls, James G.; Krick, Jessica E.; Carey, Sean J.; Stauffer, John R.; Grillmair, Carl J.; Lowrance, Patrick

    2016-06-01

    We examine the repeatability, reliability, and accuracy of differential exoplanet eclipse depth measurements made using the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope during the post-cryogenic mission. At infrared wavelengths secondary eclipses and phase curves are powerful tools for studying a planet’s atmosphere. Extracting information about atmospheres, however, is extremely challenging due to the small differential signals, which are often at the level of 100 parts per million (ppm) or smaller, and require the removal of significant instrumental systematics. For the IRAC 3.6 and 4.5μm InSb detectors that remain active on post-cryogenic Spitzer, the interplay of residual telescope pointing fluctuations with intrapixel gain variations in the moderately under sampled camera is the largest source of time-correlated noise. Over the past decade, a suite of techniques for removing this noise from IRAC data has been developed independently by various investigators. In summer 2015, the Spitzer Science Center hosted a Data Challenge in which seven exoplanet expert teams, each using a different noise-removal method, were invited to analyze 10 eclipse measurements of the hot Jupiter XO-3 b, as well as a complementary set of 10 simulated measurements. In this contribution we review the results of the Challenge. We describe statistical tools to assess the repeatability, reliability, and validity of data reduction techniques, and to compare and (perhaps) choose between techniques.

  6. Tempest: Mesoscale test case suite results and the effect of order-of-accuracy on pressure gradient force errors

    NASA Astrophysics Data System (ADS)

    Guerra, J. E.; Ullrich, P. A.

    2014-12-01

    Tempest is a new non-hydrostatic atmospheric modeling framework that allows for investigation and intercomparison of high-order numerical methods. It is composed of a dynamical core based on a finite-element formulation of arbitrary order operating on cubed-sphere and Cartesian meshes with topography. The underlying technology is briefly discussed, including a novel Hybrid Finite Element Method (HFEM) vertical coordinate coupled with high-order Implicit/Explicit (IMEX) time integration to control vertically propagating sound waves. Here, we show results from a suite of Mesoscale testing cases from the literature that demonstrate the accuracy, performance, and properties of Tempest on regular Cartesian meshes. The test cases include wave propagation behavior, Kelvin-Helmholtz instabilities, and flow interaction with topography. Comparisons are made to existing results highlighting improvements made in resolving atmospheric dynamics in the vertical direction where many existing methods are deficient.

  7. Accuracy Rates of Sex Estimation by Forensic Anthropologists through Comparison with DNA Typing Results in Forensic Casework.

    PubMed

    Thomas, Richard M; Parks, Connie L; Richard, Adam H

    2016-09-01

    A common task in forensic anthropology involves the estimation of the biological sex of a decedent by exploiting the sexual dimorphism between males and females. Estimation methods are often based on analysis of skeletal collections of known sex and most include a research-based accuracy rate. However, the accuracy rates of sex estimation methods in actual forensic casework have rarely been studied. This article uses sex determinations based on DNA results from 360 forensic cases to develop accuracy rates for sex estimations conducted by forensic anthropologists. The overall rate of correct sex estimation from these cases is 94.7% with increasing accuracy rates as more skeletal material is available for analysis and as the education level and certification of the examiner increases. Nine of 19 incorrect assessments resulted from cases in which one skeletal element was available, suggesting that the use of an "undetermined" result may be more appropriate for these cases.

  8. Speed and Accuracy of Absolute Pitch Judgments: Some Latter-Day Results.

    ERIC Educational Resources Information Center

    Carroll, John B.

    Nine subjects, 5 of whom claimed absolute pitch (AP) ability were instructed to rapidly strike notes on the piano to match randomized tape-recorded piano notes. Stimulus set sizes were 64, 16, or 4 consecutive semitones, or 7 diatonic notes of a designated octave. A control task involved motor movements to notes announced in advance. Accuracy,…

  9. Accuracy of Korean-Mini-Mental Status Examination Based on Seoul Neuro-Psychological Screening Battery II Results

    PubMed Central

    Kang, In-Woong; Beom, In-Gyu; Cho, Ji-Yeon

    2016-01-01

    Background The Korean-Mini-Mental Status Examination (K-MMSE) is a dementia-screening test that can be easily applied in both community and clinical settings. However, in 20% to 30% of cases, the K-MMSE produces a false negative response. This suggests that it is necessary to evaluate the accuracy of K-MMSE as a screening test for dementia, which can be achieved through comparison of K-MMSE and Seoul Neuropsychological Screening Battery (SNSB)-II results. Methods The study included 713 subjects (male 534, female 179; mean age, 69.3±6.9 years). All subjects were assessed using K-MMSE and SNSB-II tests, the results of which were divided into normal and abnormal in 15 percentile standards. Results The sensitivity of the K-MMSE was 48.7%, with a specificity of 89.9%. The incidence of false positive and negative results totaled 10.1% and 51.2%, respectively. In addition, the positive predictive value of the K-MMSE was 87.1%, while the negative predictive value was 55.6%. The false-negative group showed cognitive impairments in regions of memory and executive function. Subsequently, in the false-positive group, subjects demonstrated reduced performance in memory recall, time orientation, attention, and calculation of K-MMSE items. Conclusion The results obtained in the study suggest that cognitive function might still be impaired even if an individual obtained a normal score on the K-MMSE. If the K-MMSE is combined with tests of memory or executive function, the accuracy of dementia diagnosis could be greatly improved. PMID:27274389

  10. Results of error correction techniques applied on two high accuracy coordinate measuring machines

    SciTech Connect

    Pace, C.; Doiron, T.; Stieren, D.; Borchardt, B.; Veale, R.; National Inst. of Standards and Technology, Gaithersburg, MD )

    1990-01-01

    The Primary Standards Laboratory at Sandia National Laboratories (SNL) and the Precision Engineering Division at the National Institute of Standards and Technology (NIST) are in the process of implementing software error correction on two nearly identical high-accuracy coordinate measuring machines (CMMs). Both machines are Moore Special Tool Company M-48 CMMs which are fitted with laser positioning transducers. Although both machines were manufactured to high tolerance levels, the overall volumetric accuracy was insufficient for calibrating standards to the levels both laboratories require. The error mapping procedure was developed at NIST in the mid 1970's on an earlier but similar model. The error mapping procedure was originally very complicated and did not make any assumptions about the rigidness of the machine as it moved, each of the possible error motions was measured at each point of the error map independently. A simpler mapping procedure was developed during the early 1980's which assumed rigid body motion of the machine. This method has been used to calibrate lower accuracy machines with a high degree of success and similar software correction schemes have been implemented by many CMM manufacturers. The rigid body model has not yet been used on highly repeatable CMMs such as the M48. In this report we present early mapping data for the two M48 CMMs. The SNL CMM was manufactured in 1985 and has been in service for approximately four years, whereas the NIST CMM was delivered in early 1989. 4 refs., 5 figs.

  11. Long-Term Trial Results Show No Mortality Benefit from Annual Prostate Cancer Screening

    Cancer.gov

    Thirteen year follow-up data from the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial show higher incidence but similar mortality among men screened annually with the prostate-specific antigen (PSA) test and digital rectal examination

  12. Results From Mars Show Electrostatic Charging of the Mars Pathfinder Sojourner Rover

    NASA Technical Reports Server (NTRS)

    Kolecki, Joseph C.; Siebert, Mark W.

    1998-01-01

    Indirect evidence (dust accumulation) has been obtained indicating that the Mars Pathfinder rover, Sojourner, experienced electrostatic charging on Mars. Lander camera images of the Sojourner rover provide distinctive evidence of dust accumulation on rover wheels during traverses, turns, and crabbing maneuvers. The sol 22 (22nd Martian "day" after Pathfinder landed) end-of-day image clearly shows fine red dust concentrated around the wheel edges with additional accumulation in the wheel hubs. A sol 41 image of the rover near the rock "Wedge" (see the next image) shows a more uniform coating of dust on the wheel drive surfaces with accumulation in the hubs similar to that in the previous image. In the sol 41 image, note particularly the loss of black-white contrast on the Wheel Abrasion Experiment strips (center wheel). This loss of contrast was also seen when dust accumulated on test wheels in the laboratory. We believe that this accumulation occurred because the Martian surface dust consists of clay-sized particles, similar to those detected by Viking, which have become electrically charged. By adhering to the wheels, the charged dust carries a net nonzero charge to the rover, raising its electrical potential relative to its surroundings. Similar charging behavior was routinely observed in an experimental facility at the NASA Lewis Research Center, where a Sojourner wheel was driven in a simulated Martian surface environment. There, as the wheel moved and accumulated dust (see the following image), electrical potentials in excess of 100 V (relative to the chamber ground) were detected by a capacitively coupled electrostatic probe located 4 mm from the wheel surface. The measured wheel capacitance was approximately 80 picofarads (pF), and the calculated charge, 8 x 10(exp -9) coulombs (C). Voltage differences of 100 V and greater are believed sufficient to produce Paschen electrical discharge in the Martian atmosphere. With an accumulated net charge of 8 x 10(exp

  13. Stem cells show promising results for lymphoedema treatment--a literature review.

    PubMed

    Toyserkani, Navid Mohamadpour; Christensen, Marlene Louise; Sheikh, Søren Paludan; Sørensen, Jens Ahm

    2015-04-01

    Lymphoedema is a debilitating condition, manifesting in excess lymphatic fluid and swelling of subcutaneous tissues. Lymphoedema is as of yet still an incurable condition and current treatment modalities are not satisfactory. The capacity of mesenchymal stem cells to promote angiogenesis, secrete growth factors, regulate the inflammatory process, and differentiate into multiple cell types make them a potential ideal therapy for lymphoedema. Adipose tissue is the richest and most accessible source of mesenchymal stem cells and they can be harvested, isolated, and used for therapy in a single stage procedure as an autologous treatment. The aim of this paper was to review all studies using mesenchymal stem cells for lymphoedema treatment with a special focus on the potential use of adipose-derived stem cells. A systematic search was performed and five preclinical and two clinical studies were found. Different stem cell sources and lymphoedema models were used in the described studies. Most studies showed a decrease in lymphoedema and an increased lymphangiogenesis when treated with stem cells and this treatment modality has so far shown great potential. The present studies are, however, subject to bias and more preclinical studies and large-scale high quality clinical trials are needed to show if this emerging therapy can satisfy expectations.

  14. AMS 14C analysis of teeth from archaeological sites showing anomalous esr dating results

    NASA Astrophysics Data System (ADS)

    Grün, Rainer; Abeyratne, Mohan; Head, John; Tuniz, Claudio; Hedges, Robert E. M.

    We have carried out AMS radiocarbon analysis on two groups of samples: the first one gave reasonable ESR age estimates and the second one yielded serious age underestinations. All samples were supposedly older than 35 ka, the oldest being around 160 ka. Two pretreatment techniques were used for radiocarbon dating: acid evolution and thermal release. Heating to 600, 750 and 900°C combined with total de-gassing at these temperatures was chosen to obtain age estimates on the organic fraction, secondary carbonates and original carbonate present in the hydroxyapatite mineral phase, respectively. All radiocarbon results present serious age underestimations. The secondary carbonate fraction gives almost modern results indicating an extremely rapid exchange of this component. Owing to this very rapid carbonate exchange it is not likely that the ESR signals used for dating are associated with the secondary carbonates. One tooth from Tabun with independent age estimates of >150 ka was further investigated by the Oxford AMS laboratory, yielding an age estimate of 1930±100 BP on the residual collagen from dentine and 18,000±160 BP on the carbonate component of the enamel bioapatite. We did not, however, find an explanation of why some samples give serious ESR underestimatioils whilst many others provide reasonable results.

  15. Animation shows promise in initiating timely cardiopulmonary resuscitation: results of a pilot study.

    PubMed

    Attin, Mina; Winslow, Katheryn; Smith, Tyler

    2014-04-01

    Delayed responses during cardiac arrest are common. Timely interventions during cardiac arrest have a direct impact on patient survival. Integration of technology in nursing education is crucial to enhance teaching effectiveness. The goal of this study was to investigate the effect of animation on nursing students' response time to cardiac arrest, including initiation of timely chest compression. Nursing students were randomized into experimental and control groups prior to practicing in a high-fidelity simulation laboratory. The experimental group was educated, by discussion and animation, about the importance of starting cardiopulmonary resuscitation upon recognizing an unresponsive patient. Afterward, a discussion session allowed students in the experimental group to gain more in-depth knowledge about the most recent changes in the cardiac resuscitation guidelines from the American Heart Association. A linear mixed model was run to investigate differences in time of response between the experimental and control groups while controlling for differences in those with additional degrees, prior code experience, and basic life support certification. The experimental group had a faster response time compared with the control group and initiated timely cardiopulmonary resuscitation upon recognition of deteriorating conditions (P < .0001). The results demonstrated the efficacy of combined teaching modalities for timely cardiopulmonary resuscitation. Providing opportunities for repetitious practice when a patient's condition is deteriorating is crucial for teaching safe practice.

  16. Aortic emboli show surprising size dependent predilection for cerebral arteries: Results from computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Carr, Ian; Schwartz, Robert; Shadden, Shawn

    2012-11-01

    Cardiac emboli can have devastating consequences if they enter the cerebral circulation, and are the most common cause of embolic stroke. Little is known about relationships of embolic origin/density/size to cerebral events; as these relationships are difficult to observe. To better understand stoke risk from cardiac and aortic emboli, we developed a computational model to track emboli from the heart to the brain. Patient-specific models of the human aorta and arteries to the brain were derived from CT angiography from 10 MHIF patients. Blood flow was modeled by the Navier-Stokes equations using pulsatile inflow at the aortic valve, and physiologic Windkessel models at the outlets. Particulate was injected at the aortic valve and tracked using modified Maxey-Riley equations with a wall collision model. Results demonstrate aortic emboli that entered the cerebral circulation through the carotid or vertebral arteries were localized to specific locations of the proximal aorta. The percentage of released particles embolic to the brain markedly increased with particle size from 0 to ~1-1.5 mm in all patients. Larger particulate became less likely to traverse the cerebral vessels. These findings are consistent with sparse literature based on transesophageal echo measurements. This work was supported in part by the National Science Foundation, award number 1157041.

  17. Initiative To Reduce Avoidable Hospitalizations Among Nursing Facility Residents Shows Promising Results.

    PubMed

    Ingber, Melvin J; Feng, Zhanlian; Khatutsky, Galina; Wang, Joyce M; Bercaw, Lawren E; Zheng, Nan Tracy; Vadnais, Alison; Coomer, Nicole M; Segelman, Micah

    2017-03-01

    Nursing facility residents are frequently admitted to the hospital, and these hospital stays are often potentially avoidable. Such hospitalizations are detrimental to patients and costly to Medicare and Medicaid. In 2012 the Centers for Medicare and Medicaid Services launched the Initiative to Reduce Avoidable Hospitalizations among Nursing Facility Residents, using evidence-based clinical and educational interventions among long-stay residents in 143 facilities in seven states. In state-specific analyses, we estimated net reductions in 2015 of 2.2-9.3 percentage points in the probability of an all-cause hospitalization and 1.4-7.2 percentage points in the probability of a potentially avoidable hospitalization for participating facility residents, relative to comparison-group members. In that year, average per resident Medicare expenditures were reduced by $60-$2,248 for all-cause hospitalizations and by $98-$577 for potentially avoidable hospitalizations. The effects for over half of the outcomes in these analyses were significant. Variability in implementation and engagement across the nursing facilities and organizations that customized and implemented the initiative helps explain the variability in the estimated effects. Initiative models that included registered nurses or nurse practitioners who provided consistent clinical care for residents demonstrated higher staff engagement and more positive outcomes, compared to models providing only education or intermittent clinical care. These results provide promising evidence of an effective approach for reducing avoidable hospitalizations among nursing facility residents.

  18. MicroRNA-155 Hallmarks Promising Accuracy for the Diagnosis of Various Carcinomas: Results from a Meta-Analysis

    PubMed Central

    Wu, Chuancheng; Liu, Qiuyan; Liu, Baoying

    2015-01-01

    Background. Recent studies have shown that microRNAs (miRNAs) have diagnostic values in various cancers. This meta-analysis seeks to summarize the global diagnostic role of miR-155 in patients with a variety of carcinomas. Methods. Eligible studies were retrieved by searching the online databases, and the bivariate meta-analysis model was employed to generate the summary receiver operator characteristic (SROC) curve. Results. A total of 17 studies dealing with various carcinomas were finally included. The results showed that single miR-155 testing allowed for the discrimination between cancer patients and healthy donors with a sensitivity of 0.82 (95% CI: 0.73–0.88) and specificity of 0.77 (95% CI: 0.70–0.83), corresponding to an area under curve (AUC) of 0.85, while a panel comprising expressions of miR-155 yielded a sensitivity of 0.76 (95% CI: 0.68–0.82) and specificity of 0.82 (95% CI: 0.77–0.86) in diagnosing cancers. The subgroup analysis displayed that serum miR-155 test harvested higher accuracy than plasma-based assay (the AUC, sensitivity, and specificity were, resp., 0.87 versus 0.73, 0.78 versus 0.74, and 0.77 versus 0.70). Conclusions. Our data suggest that single miR-155 profiling has a potential to be used as a screening test for various carcinomas, and parallel testing of miR-155 confers an improved specificity compared to single miR-155 analysis. PMID:25918453

  19. Thematic accuracy of the 1992 National Land-Cover Data for the eastern United States: Statistical methodology and regional results

    USGS Publications Warehouse

    Stehman, S.V.; Wickham, J.D.; Smith, J.H.; Yang, L.

    2003-01-01

    The accuracy of the 1992 National Land-Cover Data (NLCD) map is assessed via a probability sampling design incorporating three levels of stratification and two stages of selection. Agreement between the map and reference land-cover labels is defined as a match between the primary or alternate reference label determined for a sample pixel and a mode class of the mapped 3×3 block of pixels centered on the sample pixel. Results are reported for each of the four regions comprising the eastern United States for both Anderson Level I and II classifications. Overall accuracies for Levels I and II are 80% and 46% for New England, 82% and 62% for New York/New Jersey (NY/NJ), 70% and 43% for the Mid-Atlantic, and 83% and 66% for the Southeast.

  20. Post-glacial landforms dating by lichenometry in Iceland - the accuracy of relative results and conversely

    NASA Astrophysics Data System (ADS)

    Decaulne, Armelle

    2014-05-01

    Lichenometry studies are carried out in Iceland since 1970 all over the country, using various techniques to solve a range of geomorphologic issues, from moraine dating and glacial advances, outwash timing, proglacial river incision, soil erosion, rock-glacier development, climate variations, to debris-flow occurrence and extreme snow-avalanche frequency. Most users have sought to date proglacial landforms in two main areas, around the southern ice-caps of Vatnajökull and Myrdalsjökull; and in Tröllaskagi in northern Iceland. Based on the results of over thirty five published studies, lichenometry is deemed to be successful dating tool in Iceland, and seems to approach an absolute dating technique at least over the last hundred years, under well constrained environmental conditions at local scale. With an increasing awareness of the methodological limitations of the technique, together with more sophisticated data treatments, predicted lichenometric 'ages' are supposedly gaining in robustness and in precision. However, comparisons between regions, and even between studies in the same area, are hindered by the use of different measurement techniques and data processing. These issues are exacerbated in Iceland by rapid environmental changes across short distances and, more generally, by the common problems surrounding lichen species mis-identification in the field; not mentioning the age discrepancy offered by other dating tools, such as tephrochronology. Some authors claim lichenometry can help to a precise reconstruction of landforms and geomorphic processes in Iceland, proposing yearly dating, others includes margin errors in their reconstructions, while some limit its use to generation identifications, refusing to overpass the nature of the gathered data and further interpretation. Finally, can lichenometry be a relatively accurate dating technique or rather an accurate relative dating tool in Iceland?

  1. Evaluation of the geomorphometric results and residual values of a robust plane fitting method applied to different DTMs of various scales and accuracy

    NASA Astrophysics Data System (ADS)

    Koma, Zsófia; Székely, Balázs; Dorninger, Peter; Kovács, Gábor

    2013-04-01

    Due to the need for quantitative analysis of various geomorphological landforms, the importance of fast and effective automatic processing of the different kind of digital terrain models (DTMs) is increasing. The robust plane fitting (segmentation) method, developed at the Institute of Photogrammetry and Remote Sensing at Vienna University of Technology, allows the processing of large 3D point clouds (containing millions of points), performs automatic detection of the planar elements of the surface via parameter estimation, and provides a considerable data reduction for the modeled area. Its geoscientific application allows the modeling of different landforms with the fitted planes as planar facets. In our study we aim to analyze the accuracy of the resulting set of fitted planes in terms of accuracy, model reliability and dependence on the input parameters. To this end we used DTMs of different scales and accuracy: (1) artificially generated 3D point cloud model with different magnitudes of error; (2) LiDAR data with 0.1 m error; (3) SRTM (Shuttle Radar Topography Mission) DTM database with 5 m accuracy; (4) DTM data from HRSC (High Resolution Stereo Camera) of the planet Mars with 10 m error. The analysis of the simulated 3D point cloud with normally distributed errors comprised different kinds of statistical tests (for example Chi-square and Kolmogorov-Smirnov tests) applied on the residual values and evaluation of dependence of the residual values on the input parameters. These tests have been repeated on the real data supplemented with the categorization of the segmentation result depending on the input parameters, model reliability and the geomorphological meaning of the fitted planes. The simulation results show that for the artificially generated data with normally distributed errors the null hypothesis can be accepted based on the residual value distribution being also normal, but in case of the test on the real data the residual value distribution is

  2. The diagnostic accuracy of a single CEA blood test in detecting colorectal cancer recurrence: Results from the FACS trial

    PubMed Central

    Nicholson, Brian D.; Primrose, John; Perera, Rafael; James, Timothy; Pugh, Sian; Mant, David

    2017-01-01

    Objective To evaluate the diagnostic accuracy of a single CEA (carcinoembryonic antigen) blood test in detecting colorectal cancer recurrence. Background Patients who have undergone curative resection for primary colorectal cancer are typically followed up with scheduled CEA testing for 5 years. Decisions to investigate further (usually by CT imaging) are based on single test results, reflecting international guidelines. Methods A secondary analysis was undertaken of data from the FACS trial (two arms included CEA testing). The composite reference standard applied included CT-CAP imaging, clinical assessment and colonoscopy. Accuracy in detecting recurrence was evaluated in terms of sensitivity, specificity, likelihood ratios, predictive values, time-dependent area under the ROC curves, and operational performance when used prospectively in clinical practice are reported. Results Of 582 patients, 104 (17.9%) developed recurrence during the 5 year follow-up period. Applying the recommended threshold of 5μg/L achieves at best 50.0% sensitivity (95% CI: 40.1–59.9%); in prospective use in clinical practice it would lead to 56 missed recurrences (53.8%; 95% CI: 44.2–64.4%) and 89 false alarms (56.7% of 157 patients referred for investigation). Applying a lower threshold of 2.5μg/L would reduce the number of missed recurrences to 36.5% (95% CI: 26.5–46.5%) but would increase the false alarms to 84.2% (924/1097 referred). Some patients are more prone to false alarms than others—at the 5μg/L threshold, the 89 episodes of unnecessary investigation were clustered in 29 individuals. Conclusion Our results demonstrated very low sensitivity for CEA, bringing to question whether it could ever be used as an independent triage test. It is not feasible to improve the diagnostic performance of a single test result by reducing the recommended action threshold because of the workload and false alarms generated. Current national and international guidelines merit re

  3. Improved Accuracy of Continuous Glucose Monitoring Systems in Pediatric Patients with Diabetes Mellitus: Results from Two Studies

    PubMed Central

    2016-01-01

    Abstract Objective: This study was designed to evaluate accuracy, performance, and safety of the Dexcom (San Diego, CA) G4® Platinum continuous glucose monitoring (CGM) system (G4P) compared with the Dexcom G4 Platinum with Software 505 algorithm (SW505) when used as adjunctive management to blood glucose (BG) monitoring over a 7-day period in youth, 2–17 years of age, with diabetes. Research Design and Methods: Youth wore either one or two sensors placed on the abdomen or upper buttocks for 7 days, calibrating the device twice daily with a uniform BG meter. Participants had one in-clinic session on Day 1, 4, or 7, during which fingerstick BG measurements (self-monitoring of blood glucose [SMBG]) were obtained every 30 ± 5 min for comparison with CGM, and in youth 6–17 years of age, reference YSI glucose measurements were obtained from arterialized venous blood collected every 15 ± 5 min for comparison with CGM. The sensor was removed by the participant/family after 7 days. Results: In comparison of 2,922 temporally paired points of CGM with the reference YSI measurement for G4P and 2,262 paired points for SW505, the mean absolute relative difference (MARD) was 17% for G4P versus 10% for SW505 (P < 0.0001). In comparison of 16,318 temporally paired points of CGM with SMBG for G4P and 4,264 paired points for SW505, MARD was 15% for G4P versus 13% for SW505 (P < 0.0001). Similarly, error grid analyses indicated superior performance with SW505 compared with G4P in comparison of CGM with YSI and CGM with SMBG results, with greater percentages of SW505 results falling within error grid Zone A or the combined Zones A plus B. There were no serious adverse events or device-related serious adverse events for either the G4P or the SW505, and there was no sensor breakoff. Conclusions: The updated algorithm offers substantial improvements in accuracy and performance in pediatric patients with diabetes. Use of CGM with improved performance has

  4. Accuracy and Precision in the Southern Hemisphere Additional Ozonesondes (SHADOZ) Dataset in Light of the JOSIE-2000 Results

    NASA Technical Reports Server (NTRS)

    Witte, Jacquelyn C.; Thompson, Anne M.; Schmidlin, F. J.; Oltmans, S. J.; Smit, H. G. J.

    2004-01-01

    Since 1998 the Southern Hemisphere ADditional OZonesondes (SHADOZ) project has provided over 2000 ozone profiles over eleven southern hemisphere tropical and subtropical stations. Balloon-borne electrochemical concentration cell (ECC) ozonesondes are used to measure ozone. The data are archived at: &ttp://croc.gsfc.nasa.gov/shadoz>. In analysis of ozonesonde imprecision within the SHADOZ dataset, Thompson et al. [JGR, 108,8238,20031 we pointed out that variations in ozonesonde technique (sensor solution strength, instrument manufacturer, data processing) could lead to station-to-station biases within the SHADOZ dataset. Imprecisions and accuracy in the SHADOZ dataset are examined in light of new data. First, SHADOZ total ozone column amounts are compared to version 8 TOMS (2004 release). As for TOMS version 7, satellite total ozone is usually higher than the integrated column amount from the sounding. Discrepancies between the sonde and satellite datasets decline two percentage points on average, compared to version 7 TOMS offsets. Second, the SHADOZ station data are compared to results of chamber simulations (JOSE-2000, Juelich Ozonesonde Intercomparison Experiment) in which the various SHADOZ techniques were evaluated. The range of JOSE column deviations from a standard instrument (-10%) in the chamber resembles that of the SHADOZ station data. It appears that some systematic variations in the SHADOZ ozone record are accounted for by differences in solution strength, data processing and instrument type (manufacturer).

  5. Conventional physical therapy and physical therapy based on reflex stimulation showed similar results in children with myelomeningocele.

    PubMed

    Aizawa, Carolina Y P; Morales, Mariana P; Lundberg, Carolina; Moura, Maria Clara D Soares de; Pinto, Fernando C G; Voos, Mariana C; Hasue, Renata H

    2017-03-01

    We aimed to investigate whether infants with myelomeningocele would improve their motor ability and functional independence after ten sessions of physical therapy and compare the outcomes of conventional physical therapy (CPT) to a physical therapy program based on reflex stimulation (RPT). Twelve children were allocated to CPT (n = 6, age 18.3 months) or RPT (n = 6, age 18.2 months). The RPT involved proprioceptive neuromuscular facilitation. Children were assessed with the Gross Motor Function Measure and the Pediatric Evaluation of Disability Inventory before and after treatment. Mann-Whitney tests compared the improvement on the two scales of CPT versus RPT and the Wilcoxon test compared CPT to RPT (before vs. after treatment). Possible correlations between the two scales were tested with Spearman correlation coefficients. Both groups showed improvement on self-care and mobility domains of both scales. There were no differences between the groups, before, or after intervention. The CPT and RPT showed similar results after ten weeks of treatment.

  6. Analysis of conservative tracer measurement results using the Frechet distribution at planted horizontal subsurface flow constructed wetlands filled with coarse gravel and showing the effect of clogging processes.

    PubMed

    Dittrich, Ernő; Klincsik, Mihály

    2015-11-01

    A mathematical process, developed in Maple environment, has been successful in decreasing the error of measurement results and in the precise calculation of the moments of corrected tracer functions. It was proved that with this process, the measured tracer results of horizontal subsurface flow constructed wetlands filled with coarse gravel (HSFCW-C) can be fitted more accurately than with the conventionally used distribution functions (Gaussian, Lognormal, Fick (Inverse Gaussian) and Gamma). This statement is true only for the planted HSFCW-Cs. The analysis of unplanted HSFCW-Cs needs more research. The result of the analysis shows that the conventional solutions (completely stirred series tank reactor (CSTR) model and convection-dispersion transport (CDT) model) cannot describe these types of transport processes with sufficient accuracy. These outcomes can help in developing better process descriptions of very difficult transport processes in HSFCW-Cs. Furthermore, a new mathematical process can be developed for the calculation of real hydraulic residence time (HRT) and dispersion coefficient values. The presented method can be generalized to other kinds of hydraulic environments.

  7. On the accuracy of a video-based drill-guidance solution for orthopedic and trauma surgery: preliminary results

    NASA Astrophysics Data System (ADS)

    Magaraggia, Jessica; Kleinszig, Gerhard; Wei, Wei; Weiten, Markus; Graumann, Rainer; Angelopoulou, Elli; Hornegger, Joachim

    2014-03-01

    Over the last years, several methods have been proposed to guide the physician during reduction and fixation of bone fractures. Available solutions often use bulky instrumentation inside the operating room (OR). The latter ones usually consist of a stereo camera, placed outside the operative field, and optical markers directly attached to both the patient and the surgical instrumentation, held by the surgeon. Recently proposed techniques try to reduce the required additional instrumentation as well as the radiation exposure to both patient and physician. In this paper, we present the adaptation and the first implementation of our recently proposed video camera-based solution for screw fixation guidance. Based on the simulations conducted in our previous work, we mounted a small camera on a drill in order to recover its tip position and axis orientation w.r.t our custom-made drill sleeve with attached markers. Since drill-position accuracy is critical, we thoroughly evaluated the accuracy of our implementation. We used an optical tracking system for ground truth data collection. For this purpose, we built a custom plate reference system and attached reflective markers to both the instrument and the plate. Free drilling was then performed 19 times. The position of the drill axis was continuously recovered using both our video camera solution and the tracking system for comparison. The recorded data covered targeting, perforation of the surface bone by the drill bit and bone drilling. The orientation of the instrument axis and the position of the instrument tip were recovered with an accuracy of 1:60 +/- 1:22° and 2:03 +/- 1:36 mm respectively.

  8. Genomic and Enzymatic Results Show Bacillus cellulosilyticus Uses a Novel Set of LPXTA Carbohydrases to Hydrolyze Polysaccharides

    PubMed Central

    Mead, David; Drinkwater, Colleen; Brumm, Phillip J.

    2013-01-01

    Background Alkaliphilic Bacillus species are intrinsically interesting due to the bioenergetic problems posed by growth at high pH and high salt. Three alkaline cellulases have been cloned, sequenced and expressed from Bacillus cellulosilyticus N-4 (Bcell) making it an excellent target for genomic sequencing and mining of biomass-degrading enzymes. Methodology/Principal Findings The genome of Bcell is a single chromosome of 4.7 Mb with no plasmids present and three large phage insertions. The most unusual feature of the genome is the presence of 23 LPXTA membrane anchor proteins; 17 of these are annotated as involved in polysaccharide degradation. These two values are significantly higher than seen in any other Bacillus species. This high number of membrane anchor proteins is seen only in pathogenic Gram-positive organisms such as Listeria monocytogenes or Staphylococcus aureus. Bcell also possesses four sortase D subfamily 4 enzymes that incorporate LPXTA-bearing proteins into the cell wall; three of these are closely related to each other and unique to Bcell. Cell fractionation and enzymatic assay of Bcell cultures show that the majority of polysaccharide degradation is associated with the cell wall LPXTA-enzymes, an unusual feature in Gram-positive aerobes. Genomic analysis and growth studies both strongly argue against Bcell being a truly cellulolytic organism, in spite of its name. Preliminary results suggest that fungal mycelia may be the natural substrate for this organism. Conclusions/Significance Bacillus cellulosilyticus N-4, in spite of its name, does not possess any of the genes necessary for crystalline cellulose degradation, demonstrating the risk of classifying microorganisms without the benefit of genomic analysis. Bcell is the first Gram-positive aerobic organism shown to use predominantly cell-bound, non-cellulosomal enzymes for polysaccharide degradation. The LPXTA-sortase system utilized by Bcell may have applications both in anchoring

  9. Overlay accuracy fundamentals

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina

    2012-03-01

    Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to < 0.5nm, it becomes crucial to include also systematic error contributions which affect the accuracy of the metrology. Here we discuss fundamental aspects of overlay accuracy and a methodology to improve accuracy significantly. We identify overlay mark imperfections and their interaction with the metrology technology, as the main source of overlay inaccuracy. The most important type of mark imperfection is mark asymmetry. Overlay mark asymmetry leads to a geometrical ambiguity in the definition of overlay, which can be ~1nm or less. It is shown theoretically and in simulations that the metrology may enhance the effect of overlay mark asymmetry significantly and lead to metrology inaccuracy ~10nm, much larger than the geometrical ambiguity. The analysis is carried out for two different overlay metrology technologies: Imaging overlay and DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.

  10. Dosimetric accuracy assessment of a treatment plan verification system for scanned proton beam radiotherapy: one-year experimental results and Monte Carlo analysis of the involved uncertainties.

    PubMed

    Molinelli, S; Mairani, A; Mirandola, A; Vilches Freixas, G; Tessonnier, T; Giordanengo, S; Parodi, K; Ciocca, M; Orecchia, R

    2013-06-07

    During one year of clinical activity at the Italian National Center for Oncological Hadron Therapy 31 patients were treated with actively scanned proton beams. Results of patient-specific quality assurance procedures are presented here which assess the accuracy of a three-dimensional dose verification technique with the simultaneous use of multiple small-volume ionization chambers. To investigate critical cases of major deviations between treatment planning system (TPS) calculated and measured data points, a Monte Carlo (MC) simulation tool was implemented for plan verification in water. Starting from MC results, the impact of dose calculation, dose delivery and measurement set-up uncertainties on plan verification results was analyzed. All resulting patient-specific quality checks were within the acceptance threshold, which was set at 5% for both mean deviation between measured and calculated doses and standard deviation. The mean deviation between TPS dose calculation and measurement was less than ±3% in 86% of the cases. When all three sources of uncertainty were accounted for, simulated data sets showed a high level of agreement, with mean and maximum absolute deviation lower than 2.5% and 5%, respectively.

  11. Dosimetric accuracy assessment of a treatment plan verification system for scanned proton beam radiotherapy: one-year experimental results and Monte Carlo analysis of the involved uncertainties

    NASA Astrophysics Data System (ADS)

    Molinelli, S.; Mairani, A.; Mirandola, A.; Vilches Freixas, G.; Tessonnier, T.; Giordanengo, S.; Parodi, K.; Ciocca, M.; Orecchia, R.

    2013-06-01

    During one year of clinical activity at the Italian National Center for Oncological Hadron Therapy 31 patients were treated with actively scanned proton beams. Results of patient-specific quality assurance procedures are presented here which assess the accuracy of a three-dimensional dose verification technique with the simultaneous use of multiple small-volume ionization chambers. To investigate critical cases of major deviations between treatment planning system (TPS) calculated and measured data points, a Monte Carlo (MC) simulation tool was implemented for plan verification in water. Starting from MC results, the impact of dose calculation, dose delivery and measurement set-up uncertainties on plan verification results was analyzed. All resulting patient-specific quality checks were within the acceptance threshold, which was set at 5% for both mean deviation between measured and calculated doses and standard deviation. The mean deviation between TPS dose calculation and measurement was less than ±3% in 86% of the cases. When all three sources of uncertainty were accounted for, simulated data sets showed a high level of agreement, with mean and maximum absolute deviation lower than 2.5% and 5%, respectively.

  12. Evaluating the velocity accuracy of an integrated GPS/INS system: Flight test results. [Global positioning system/inertial navigation systems (GPS/INS)

    SciTech Connect

    Owen, T.E.; Wardlaw, R.

    1991-01-01

    Verifying the velocity accuracy of a GPS receiver or an integrated GPS/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data to evaluate the accuracy of an integrated GPS/INS system are reported. Emphasis is placed on obtaining high accuracy estimates of the velocity error of the integrated system in order to verify that velocity accuracy is maintained during both linear and circular trajectories. Three different reference systems operating in parallel during flight tests are used to independently determine the position and velocity of an aircraft in flight. They are a transponder/interrogator ranging system, a laser tracker, and GPS carrier phase processing. Results obtained from these reference systems are compared against each other and against an integrated real time differential based GPS/INS system to arrive at a set of conclusions about the accuracy of the integrated system.

  13. A collaborative accountable care model in three practices showed promising early results on costs and quality of care.

    PubMed

    Salmon, Richard B; Sanderson, Mark I; Walters, Barbara A; Kennedy, Karen; Flores, Robert C; Muney, Alan M

    2012-11-01

    Cigna's Collaborative Accountable Care initiative provides financial incentives to physician groups and integrated delivery systems to improve the quality and efficiency of care for patients in commercial open-access benefit plans. Registered nurses who serve as care coordinators employed by participating practices are a central feature of the initiative. They use patient-specific reports and practice performance reports provided by Cigna to improve care coordination, identify and close care gaps, and address other opportunities for quality improvement. We report interim quality and cost results for three geographically and structurally diverse provider practices in Arizona, New Hampshire, and Texas. Although not statistically significant, these early results revealed favorable trends in total medical costs and quality of care, suggesting that a shared-savings accountable care model and collaborative support from the payer can enable practices to take meaningful steps toward full accountability for care quality and efficiency.

  14. Preclinical Evaluation of the Accuracy of HIFU Treatments Using a Tumor-Mimic Model. Results of Animal Experiments

    NASA Astrophysics Data System (ADS)

    Melodelima, D.; N'Djin, W. A.; Parmentier, H.; Rivoire, M.; Chapelon, J. Y.

    2009-04-01

    Presented in this paper is a tumor-mimic model that allows the evaluation at a preclinical stage of the targeting accuracy of HIFU treatments in the liver. The tumor-mimics were made by injecting a warm mixture of agarose, cellulose, and glycerol that polymerizes immediately in hepatic tissue and forms a 1 cm discrete lesion that is detectable by ultrasound imaging and gross pathology. Three studies were conducted: (i) in vitro experiments were conducted to study acoustical proprieties of the tumor-mimics, (ii) animal experiments were conducted in ten pigs to evaluate the tolerance of the tumor-mimics at mid-term (30 days), (iii) ultrasound-guided HIFU ablation has been performed in ten pigs with tumor-mimics to demonstrate that it is possible to treat a predetermined zone accurately. The attenuation of tumor-mimics was 0.39 dB.cm-1 at 1 MHz, the ultrasound propagation velocity was 1523 m.s-1, and the acoustic impedance was 1.8 MRayls. The pigs tolerated tumor-mimics and treatment well over the experimental period. Tumor-mimics were visible with high contrast on ultrasound images. In addition, it has been demonstrated by using the tumor-mimic as a reference target, that tissue destruction induced by HIFU and observed on gross pathology corresponded to the targeted area on the ultrasound images. The average difference between the predetermined location of the HIFU ablation and the actual coagulated area was 16%. These tumor-mimics are identifiable by ultrasound imaging, they do not modify the geometry of HIFU lesions and thus constitutes a viable mimic of tumors indicated for HIFU therapy.

  15. Volar locking distal radius plates show better short-term results than other treatment options: A prospective randomised controlled trial

    PubMed Central

    Drobetz, Herwig; Koval, Lidia; Weninger, Patrick; Luscombe, Ruth; Jeffries, Paula; Ehrendorfer, Stefan; Heal, Clare

    2016-01-01

    AIM To compare the outcomes of displaced distal radius fractures treated with volar locking plates and with immediate postoperative mobilisation with the outcomes of these fractures treated with modalities that necessitate 6 wk wrist immobilisation. METHODS A prospective, randomised controlled single-centre trial was conducted with 56 patients who had a displaced radius fracture were randomised to treatment either with a volar locking plate (n = 29), or another treatment modality (n = 27; cast immobilisation with or without wires or external fixator). Outcomes were measured at 12 wk. Functional outcome scores measured were the Patient-Rated Wrist Evaluation (PRWE) Score; Disabilities of the Arm, Shoulder and Hand and activities of daily living (ADLs). Clinical outcomes were wrist range of motion and grip strength. Radiographic parameters were volar inclination and ulnar variance. RESULTS Patients in the volar locking plate group had significantly better PRWE scores, ADL scores, grip strength and range of extension at three months compared with the control group. All radiological parameters were significantly better in the volar locking plate group at 3 mo. CONCLUSION The present study suggests that volar locking plates produced significantly better functional and clinical outcomes at 3 mo compared with other treatment modalities. Anatomical reduction was significantly more likely to be preserved in the plating group. Level of evidence: II. PMID:27795951

  16. Selection Indices and Multivariate Analysis Show Similar Results in the Evaluation of Growth and Carcass Traits in Beef Cattle

    PubMed Central

    Brito Lopes, Fernando; da Silva, Marcelo Corrêa; Magnabosco, Cláudio Ulhôa; Goncalves Narciso, Marcelo; Sainz, Roberto Daniel

    2016-01-01

    This research evaluated a multivariate approach as an alternative tool for the purpose of selection regarding expected progeny differences (EPDs). Data were fitted using a multi-trait model and consisted of growth traits (birth weight and weights at 120, 210, 365 and 450 days of age) and carcass traits (longissimus muscle area (LMA), back-fat thickness (BF), and rump fat thickness (RF)), registered over 21 years in extensive breeding systems of Polled Nellore cattle in Brazil. Multivariate analyses were performed using standardized (zero mean and unit variance) EPDs. The k mean method revealed that the best fit of data occurred using three clusters (k = 3) (P < 0.001). Estimates of genetic correlation among growth and carcass traits and the estimates of heritability were moderate to high, suggesting that a correlated response approach is suitable for practical decision making. Estimates of correlation between selection indices and the multivariate index (LD1) were moderate to high, ranging from 0.48 to 0.97. This reveals that both types of indices give similar results and that the multivariate approach is reliable for the purpose of selection. The alternative tool seems very handy when economic weights are not available or in cases where more rapid identification of the best animals is desired. Interestingly, multivariate analysis allowed forecasting information based on the relationships among breeding values (EPDs). Also, it enabled fine discrimination, rapid data summarization after genetic evaluation, and permitted accounting for maternal ability and the genetic direct potential of the animals. In addition, we recommend the use of longissimus muscle area and subcutaneous fat thickness as selection criteria, to allow estimation of breeding values before the first mating season in order to accelerate the response to individual selection. PMID:26789008

  17. Selection Indices and Multivariate Analysis Show Similar Results in the Evaluation of Growth and Carcass Traits in Beef Cattle.

    PubMed

    Brito Lopes, Fernando; da Silva, Marcelo Corrêa; Magnabosco, Cláudio Ulhôa; Goncalves Narciso, Marcelo; Sainz, Roberto Daniel

    2016-01-01

    This research evaluated a multivariate approach as an alternative tool for the purpose of selection regarding expected progeny differences (EPDs). Data were fitted using a multi-trait model and consisted of growth traits (birth weight and weights at 120, 210, 365 and 450 days of age) and carcass traits (longissimus muscle area (LMA), back-fat thickness (BF), and rump fat thickness (RF)), registered over 21 years in extensive breeding systems of Polled Nellore cattle in Brazil. Multivariate analyses were performed using standardized (zero mean and unit variance) EPDs. The k mean method revealed that the best fit of data occurred using three clusters (k = 3) (P < 0.001). Estimates of genetic correlation among growth and carcass traits and the estimates of heritability were moderate to high, suggesting that a correlated response approach is suitable for practical decision making. Estimates of correlation between selection indices and the multivariate index (LD1) were moderate to high, ranging from 0.48 to 0.97. This reveals that both types of indices give similar results and that the multivariate approach is reliable for the purpose of selection. The alternative tool seems very handy when economic weights are not available or in cases where more rapid identification of the best animals is desired. Interestingly, multivariate analysis allowed forecasting information based on the relationships among breeding values (EPDs). Also, it enabled fine discrimination, rapid data summarization after genetic evaluation, and permitted accounting for maternal ability and the genetic direct potential of the animals. In addition, we recommend the use of longissimus muscle area and subcutaneous fat thickness as selection criteria, to allow estimation of breeding values before the first mating season in order to accelerate the response to individual selection.

  18. Summary Results of the Neptun Boil-Off Experiments to Investigate the Accuracy and Cooling Influence of LOFT Cladding-Surface Thermocouples (System 00)

    SciTech Connect

    E. L. Tolman S. N. Aksan

    1981-10-01

    Nine boil-off experiments were conducted in the Swiss NEPTUN Facility primarily to obtain experimental data for assessing the perturbation effects of LOFT thermocouples during simulated small-break core uncovery conditions. The data will also be useful in assessing computer model capability to predict thermal hydraulic response data for this type of experiment. System parameters that were varied for these experiments included heater rod power, system pressure, and initial coolant subcooling. The experiments showed that the LOFT thermocouples do not cause a significant cooling influence in the rods to which they are attached. Furthermore, the accuracy of the LOFT thermocouples is within 20 K at the peak cladding temperature zone.

  19. Linear and Logarithmic Speed-Accuracy Trade-Offs in Reciprocal Aiming Result from Task-Specific Parameterization of an Invariant Underlying Dynamics

    ERIC Educational Resources Information Center

    Bongers, Raoul M.; Fernandez, Laure; Bootsma, Reinoud J.

    2009-01-01

    The authors examined the origins of linear and logarithmic speed-accuracy trade-offs from a dynamic systems perspective on motor control. In each experiment, participants performed 2 reciprocal aiming tasks: (a) a velocity-constrained task in which movement time was imposed and accuracy had to be maximized, and (b) a distance-constrained task in…

  20. Results from a round-robin study assessing the precision and accuracy of LA-ICPMS U/Pb geochronology of zircon

    NASA Astrophysics Data System (ADS)

    Hanchar, J. M.

    2009-12-01

    A round-robin study was undertaken to assess the current state of precision and accuracy that can be achieved in LA-ICPMS U/Pb geochronology of zircon. The initial plan was to select abundant, well-characterized zircon samples to distribute to participants in the study. Three suitable samples were found, evaluated, and dated using ID-TIMS. Twenty-five laboratories in North America and Europe were asked to participate in the study. Eighteen laboratories agreed to participate, of which seventeen submitted final results. It was decided at the outset of the project that the identities of the participating researchers and laboratories not be revealed until the manuscript stemming from the project was completed. Participants were sent either fragments of zircon crystal or whole zircon crystals, selected randomly after being thoroughly mixed. Participants were asked to conform to specific requirements. These include providing all analytical conditions and equipment used, submission of all data acquired, and submitting their preferred data and preferred ages for the three samples. The participating researchers used a wide range of analytical methods (e.g., instrumentation, data reduction, error propagation) for the LA-ICPMS U/Th geochronology. These combined factors made it difficult for direct comparison of the results that were submitted. Most of the LA-ICPMS results submitted were within 2% r.s.d. of the ID-TIMS values for the three samples in the study. However, the error bars for the majority of the LA-ICPMS results for the three samples did not overlap with the ID-TIMS results. These results suggest a general underestimation of the errors calculated for the LA-ICPMS analyses U/Pb zircon analyses.

  1. "The Show"

    ERIC Educational Resources Information Center

    Gehring, John

    2004-01-01

    For the past 16 years, the blue-collar city of Huntington, West Virginia, has rolled out the red carpet to welcome young wrestlers and their families as old friends. They have come to town chasing the same dream for a spot in what many of them call "The Show". For three days, under the lights of an arena packed with 5,000 fans, the…

  2. High-accuracy, high-precision, high-resolution, continuous monitoring of urban greenhouse gas emissions? Results to date from INFLUX

    NASA Astrophysics Data System (ADS)

    Davis, K. J.; Brewer, A.; Cambaliza, M. O. L.; Deng, A.; Hardesty, M.; Gurney, K. R.; Heimburger, A. M. F.; Karion, A.; Lauvaux, T.; Lopez-Coto, I.; McKain, K.; Miles, N. L.; Patarasuk, R.; Prasad, K.; Razlivanov, I. N.; Richardson, S.; Sarmiento, D. P.; Shepson, P. B.; Sweeney, C.; Turnbull, J. C.; Whetstone, J. R.; Wu, K.

    2015-12-01

    The Indianapolis Flux Experiment (INFLUX) is testing the boundaries of our ability to use atmospheric measurements to quantify urban greenhouse gas (GHG) emissions. The project brings together inventory assessments, tower-based and aircraft-based atmospheric measurements, and atmospheric modeling to provide high-accuracy, high-resolution, continuous monitoring of emissions of GHGs from the city. Results to date include a multi-year record of tower and aircraft based measurements of the urban CO2 and CH4 signal, long-term atmospheric modeling of GHG transport, and emission estimates for both CO2 and CH4 based on both tower and aircraft measurements. We will present these emissions estimates, the uncertainties in each, and our assessment of the primary needs for improvements in these emissions estimates. We will also present ongoing efforts to improve our understanding of atmospheric transport and background atmospheric GHG mole fractions, and to disaggregate GHG sources (e.g. biogenic vs. fossil fuel CO2 fluxes), topics that promise significant improvement in urban GHG emissions estimates.

  3. Accuracy and Precision in the Southern Hemisphere Additional Ozonesondes (SHADOZ) Dataset 1998-2000 in Light of the JOSIE-2000 Results

    NASA Technical Reports Server (NTRS)

    Witte, J. C.; Thompson, A. M.; Schmidlin, F. J.; Oltmans, S. J.; McPeters, R. D.; Smit, H. G. J.

    2003-01-01

    A network of 12 southern hemisphere tropical and subtropical stations in the Southern Hemisphere ADditional OZonesondes (SHADOZ) project has provided over 2000 profiles of stratospheric and tropospheric ozone since 1998. Balloon-borne electrochemical concentration cell (ECC) ozonesondes are used with standard radiosondes for pressure, temperature and relative humidity measurements. The archived data are available at:http: //croc.gsfc.nasa.gov/shadoz. In Thompson et al., accuracies and imprecisions in the SHADOZ 1998- 2000 dataset were examined using ground-based instruments and the TOMS total ozone measurement (version 7) as references. Small variations in ozonesonde technique introduced possible biases from station-to-station. SHADOZ total ozone column amounts are now compared to version 8 TOMS; discrepancies between the two datasets are reduced 2\\% on average. An evaluation of ozone variations among the stations is made using the results of a series of chamber simulations of ozone launches (JOSIE-2000, Juelich Ozonesonde Intercomparison Experiment) in which a standard reference ozone instrument was employed with the various sonde techniques used in SHADOZ. A number of variations in SHADOZ ozone data are explained when differences in solution strength, data processing and instrument type (manufacturer) are taken into account.

  4. Equations of State for Mixtures: Results from DFT Simulations of Xenon/Ethane Mixtures Compared to High Accuracy Validation Experiments on Z

    NASA Astrophysics Data System (ADS)

    Magyar, Rudolph

    2013-06-01

    We report a computational and validation study of equation of state (EOS) properties of liquid / dense plasma mixtures of xenon and ethane to explore and to illustrate the physics of the molecular scale mixing of light elements with heavy elements. Accurate EOS models are crucial to achieve high-fidelity hydrodynamics simulations of many high-energy-density phenomena such as inertial confinement fusion and strong shock waves. While the EOS is often tabulated for separate species, the equation of state for arbitrary mixtures is generally not available, requiring properties of the mixture to be approximated by combining physical properties of the pure systems. The main goal of this study is to access how accurate this approximation is under shock conditions. Density functional theory molecular dynamics (DFT-MD) at elevated-temperature and pressure is used to assess the thermodynamics of the xenon-ethane mixture. The simulations are unbiased as to elemental species and therefore provide comparable accuracy when describing total energies, pressures, and other physical properties of mixtures as they do for pure systems. In addition, we have performed shock compression experiments using the Sandia Z-accelerator on pure xenon, ethane, and various mixture ratios thereof. The Hugoniot results are compared to the DFT-MD results and the predictions of different rules for combing EOS tables. The DFT-based simulation results compare well with the experimental points, and it is found that a mixing rule based on pressure equilibration performs reliably well for the mixtures considered. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  5. THEMATIC ACCURACY OF THE 1992 NATIONAL LAND-COVER DATA (NLCD) FOR THE EASTERN UNITED STATES: STATISTICAL METHODOLOGY AND REGIONAL RESULTS

    EPA Science Inventory

    The accuracy of the National Land Cover Data (NLCD) map is assessed via a probability sampling design incorporating three levels of stratification and two stages of selection. Agreement between the map and reference land-cover labels is defined as a match between the primary or a...

  6. Assessment of the improvements in accuracy of aerosol characterization resulted from additions of polarimetric measurements to intensity-only observations using GRASP algorithm (Invited)

    NASA Astrophysics Data System (ADS)

    Dubovik, O.; Litvinov, P.; Lapyonok, T.; Herman, M.; Fedorenko, A.; Lopatin, A.; Goloub, P.; Ducos, F.; Aspetsberger, M.; Planer, W.; Federspiel, C.

    2013-12-01

    During last few years we were developing GRASP (Generalized Retrieval of Aerosol and Surface Properties) algorithm designed for the enhanced characterization of aerosol properties from spectral, multi-angular polarimetric remote sensing observations. The concept of GRASP essentially relies on the accumulated positive research heritage from previous remote sensing aerosol retrieval developments, in particular those from the AERONET and POLDER retrieval activities. The details of the algorithm are described by Dubovik et al. (Atmos. Meas. Tech., 4, 975-1018, 2011). The GRASP retrieves properties of both aerosol and land surface reflectance in cloud-free environments. It is based on highly advanced statistically optimized fitting and deduces nearly 50 unknowns for each observed site. The algorithm derives a similar set of aerosol parameters as AERONET including detailed particle size distribution, the spectrally dependent the complex index of refraction and the fraction of non-spherical particles. The algorithm uses detailed aerosol and surface models and fully accounts for all multiple interactions of scattered solar light with aerosol, gases and the underlying surface. All calculations are done on-line without using traditional look-up tables. In addition, the algorithm uses the new multi-pixel retrieval concept - a simultaneous fitting of a large group of pixels with additional constraints limiting the time variability of surface properties and spatial variability of aerosol properties. This principle is expected to result in higher consistency and accuracy of aerosol products compare to conventional approaches especially over bright surfaces where information content of satellite observations in respect to aerosol properties is limited. The GRASP is a highly versatile algorithm that allows input from both satellite and ground-based measurements. It also has essential flexibility in measurement processing. For example, if observation data set includes spectral

  7. T-cell lines from 2 patients with adenosine deaminase (ADA) deficiency showed the restoration of ADA activity resulted from the reversion of an inherited mutation.

    PubMed

    Ariga, T; Oda, N; Yamaguchi, K; Kawamura, N; Kikuta, H; Taniuchi, S; Kobayashi, Y; Terada, K; Ikeda, H; Hershfield, M S; Kobayashi, K; Sakiyama, Y

    2001-05-01

    Inherited deficiency of adenosine deaminase (ADA) results in one of the autosomal recessive forms of severe combined immunodeficiency. This report discusses 2 patients with ADA deficiency from different families, in whom a possible reverse mutation had occurred. The novel mutations were identified in the ADA gene from the patients, and both their parents were revealed to be carriers. Unexpectedly, established patient T-cell lines, not B-cell lines, showed half-normal levels of ADA enzyme activity. Reevaluation of the mutations in these T-cell lines indicated that one of the inherited ADA gene mutations was reverted in both patients. At least one of the patients seemed to possess the revertant cells in vivo; however, the mutant cells might have overcome the revertant after receiving ADA enzyme replacement therapy. These findings may have significant implications regarding the prospects for stem cell gene therapy for ADA deficiency.

  8. How often do German children and adolescents show signs of common mental health problems? Results from different methodological approaches – a cross-sectional study

    PubMed Central

    2014-01-01

    Background Child and adolescent mental health problems are ubiquitous and burdensome. Their impact on functional disability, the high rates of accompanying medical illnesses and the potential to last until adulthood make them a major public health issue. While methodological factors cause variability of the results from epidemiological studies, there is a lack of prevalence rates of mental health problems in children and adolescents according to ICD-10 criteria from nationally representative samples. International findings suggest only a small proportion of children with function impairing mental health problems receive treatment, but information about the health care situation of children and adolescents is scarce. The aim of this epidemiological study was a) to classify symptoms of common mental health problems according to ICD-10 criteria in order to compare the statistical and clinical case definition strategies using a single set of data and b) to report ICD-10 codes from health insurance claims data. Methods a) Based on a clinical expert rating, questionnaire items were mapped on ICD-10 criteria; data from the Mental Health Module (BELLA study) were analyzed for relevant ICD-10 and cut-off criteria; b) Claims data were analyzed for relevant ICD-10 codes. Results According to parent report 7.5% (n = 208) met the ICD-10 criteria of a mild depressive episode and 11% (n = 305) showed symptoms of depression according to cut-off score; Anxiety is reported in 5.6% (n = 156) and 11.6% (n = 323), conduct disorder in 15.2% (n = 373) and 14.6% (n = 357). Self-reported symptoms in 11 to 17 year olds resulted in 15% (n = 279) reporting signs of a mild depression according to ICD-10 criteria (vs. 16.7% (n = 307) based on cut-off) and 10.9% (n = 201) reported symptoms of anxiety (vs. 15.4% (n = 283)). Results from routine data identify 0.9% (n = 1,196) with a depression diagnosis, 3.1% (n = 6,729) with anxiety and 1.4% (n

  9. Assessing effects of the e-Chasqui laboratory information system on accuracy and timeliness of bacteriology results in the Peruvian tuberculosis program.

    PubMed

    Blaya, Joaquin A; Shin, Sonya S; Yagui, Martin J A; Yale, Gloria; Suarez, Carmen; Asencios, Luis; Fraser, Hamish

    2007-10-11

    We created a web-based laboratory information system, e-Chasqui to connect public laboratories to health centers to improve communication and analysis. After one year, we performed a pre and post assessment of communication delays and found that e-Chasqui maintained the average delay but eliminated delays of over 60 days. Adding digital verification maintained the average delay, but should increase accuracy. We are currently performing a randomized evaluation of the impacts of e-Chasqui.

  10. Transgene silencing of the Hutchinson-Gilford progeria syndrome mutation results in a reversible bone phenotype, whereas resveratrol treatment does not show overall beneficial effects.

    PubMed

    Strandgren, Charlotte; Nasser, Hasina Abdul; McKenna, Tomás; Koskela, Antti; Tuukkanen, Juha; Ohlsson, Claes; Rozell, Björn; Eriksson, Maria

    2015-08-01

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder that is most commonly caused by a de novo point mutation in exon 11 of the LMNA gene, c.1824C>T, which results in an increased production of a truncated form of lamin A known as progerin. In this study, we used a mouse model to study the possibility of recovering from HGPS bone disease upon silencing of the HGPS mutation, and the potential benefits from treatment with resveratrol. We show that complete silencing of the transgenic expression of progerin normalized bone morphology and mineralization already after 7 weeks. The improvements included lower frequencies of rib fractures and callus formation, an increased number of osteocytes in remodeled bone, and normalized dentinogenesis. The beneficial effects from resveratrol treatment were less significant and to a large extent similar to mice treated with sucrose alone. However, the reversal of the dental phenotype of overgrown and laterally displaced lower incisors in HGPS mice could be attributed to resveratrol. Our results indicate that the HGPS bone defects were reversible upon suppressed transgenic expression and suggest that treatments targeting aberrant progerin splicing give hope to patients who are affected by HGPS.

  11. Methods for improving accuracy and extending results beyond periods covered by traditional ground-truth in remote sensing classification of a complex landscape

    NASA Astrophysics Data System (ADS)

    Mueller-Warrant, George W.; Whittaker, Gerald W.; Banowetz, Gary M.; Griffith, Stephen M.; Barnhart, Bradley L.

    2015-06-01

    Successful development of approaches to quantify impacts of diverse landuse and associated agricultural management practices on ecosystem services is frequently limited by lack of historical and contemporary landuse data. We hypothesized that ground truth data from one year could be used to extrapolate previous or future landuse in a complex landscape where cropping systems do not generally change greatly from year to year because the majority of crops are established perennials or the same annual crops grown on the same fields over multiple years. Prior to testing this hypothesis, it was first necessary to classify 57 major landuses in the Willamette Valley of western Oregon from 2005 to 2011 using normal same year ground-truth, elaborating on previously published work and traditional sources such as Cropland Data Layers (CDL) to more fully include minor crops grown in the region. Available remote sensing data included Landsat, MODIS 16-day composites, and National Aerial Imagery Program (NAIP) imagery, all of which were resampled to a common 30 m resolution. The frequent presence of clouds and Landsat7 scan line gaps forced us to conduct of series of separate classifications in each year, which were then merged by choosing whichever classification used the highest number of cloud- and gap-free bands at any given pixel. Procedures adopted to improve accuracy beyond that achieved by maximum likelihood pixel classification included majority-rule reclassification of pixels within 91,442 Common Land Unit (CLU) polygons, smoothing and aggregation of areas outside the CLU polygons, and majority-rule reclassification over time of forest and urban development areas. Final classifications in all seven years separated annually disturbed agriculture, established perennial crops, forest, and urban development from each other at 90 to 95% overall 4-class validation accuracy. In the most successful use of subsequent year ground-truth data to classify prior year landuse, an

  12. Urinary Biomarker Panel to Improve Accuracy in Predicting Prostate Biopsy Result in Chinese Men with PSA 4–10 ng/mL

    PubMed Central

    Zhou, Yongqiang; Li, Yun; Li, Xiangnan

    2017-01-01

    This study aims to evaluate the effectiveness and clinical performance of a panel of urinary biomarkers to diagnose prostate cancer (PCa) in Chinese men with PSA levels between 4 and 10 ng/mL. A total of 122 patients with PSA levels between 4 and 10 ng/mL who underwent consecutive prostate biopsy at three hospitals in China were recruited. First-catch urine samples were collected after an attentive prostate massage. Urinary mRNA levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The predictive accuracy of these biomarkers and prediction models was assessed by the area under the curve (AUC) of the receiver-operating characteristic (ROC) curve. The diagnostic accuracy of PCA3, PSGR, and MALAT-1 was superior to that of PSA. PCA3 performed best, with an AUC of 0.734 (95% CI: 0.641, 0.828) followed by MALAT-1 with an AUC of 0.727 (95% CI: 0.625, 0.829) and PSGR with an AUC of 0.666 (95% CI: 0.575, 0.749). The diagnostic panel with age, prostate volume, % fPSA, PCA3 score, PSGR score, and MALAT-1 score yielded an AUC of 0.857 (95% CI: 0.780, 0.933). At a threshold probability of 20%, 47.2% of unnecessary biopsies may be avoided whereas only 6.2% of PCa cases may be missed. This urinary panel may improve the current diagnostic modality in Chinese men with PSA levels between 4 and 10 ng/mL. PMID:28293631

  13. Numerical accuracy assessment

    NASA Astrophysics Data System (ADS)

    Boerstoel, J. W.

    1988-12-01

    A framework is provided for numerical accuracy assessment. The purpose of numerical flow simulations is formulated. This formulation concerns the classes of aeronautical configurations (boundaries), the desired flow physics (flow equations and their properties), the classes of flow conditions on flow boundaries (boundary conditions), and the initial flow conditions. Next, accuracy and economical performance requirements are defined; the final numerical flow simulation results of interest should have a guaranteed accuracy, and be produced for an acceptable FLOP-price. Within this context, the validation of numerical processes with respect to the well known topics of consistency, stability, and convergence when the mesh is refined must be done by numerical experimentation because theory gives only partial answers. This requires careful design of text cases for numerical experimentation. Finally, the results of a few recent evaluation exercises of numerical experiments with a large number of codes on a few test cases are summarized.

  14. Storytelling Slide Shows to Improve Diabetes and High Blood Pressure Knowledge and Self-Efficacy: Three-Year Results among Community Dwelling Older African Americans

    ERIC Educational Resources Information Center

    Bertera, Elizabeth M.

    2014-01-01

    This study combined the African American tradition of oral storytelling with the Hispanic medium of "Fotonovelas." A staggered pretest posttest control group design was used to evaluate four Storytelling Slide Shows on health that featured community members. A total of 212 participants were recruited for the intervention and 217 for the…

  15. Mathematical modelling in Matlab of the experimental results shows the electrochemical potential difference - temperature of the WC coatings immersed in a NaCl solution

    NASA Astrophysics Data System (ADS)

    Benea, M. L.; Benea, O. D.

    2016-02-01

    The method used for purchasing the corrosion behaviour the WC coatings deposited by plasma spraying, on a martensitic stainless steel substrate consists in measuring the electrochemical potential of the coating, respectively that of the substrate, immersed in a NaCl solution as corrosive agent. The mathematical processing of the obtained experimental results in Matlab allowed us to make some correlations between the electrochemical potential of the coating and the solution temperature is very well described by some curves having equations obtained by interpolation order 4.

  16. In axial spondyloarthritis, never smokers, ex-smokers and current smokers show a gradient of increasing disease severity - results from the Scotland Registry for Ankylosing Spondylitis (SIRAS).

    PubMed

    Jones, Gareth T; Ratz, Tiara; Dean, Linda E; Macfarlane, Gary J; Atzeni, Fabiola

    2016-11-29

    Objectives To examine the relationship between smoking, smoking cessation, and disease characteristics/quality of life (QoL) in spondyloarthritis. Methods The Scotland Registry for Ankylosing Spondylitis collects data from clinically diagnosed patients with spondyloarthritis. Clinical data, including Bath Ankylosing Spondylitis indices of disease activity (BASDAI) and function (BASFI), was obtained from medical records. Postal questionnaires provided information on smoking status and QoL (Ankylosing Spondylitis QoL questionnaire; ASQoL). Linear and logistic regression quantified the effect of smoking, and smoking cessation, on various disease-specific and QoL outcomes, adjusting for age, sex, deprivation, education and alcohol status. Results are presented as regression coefficients (β) or odds ratios (OR) with 95% confidence intervals. Results 946 participants provided data (male 73.5%, mean age 52yrs). Current smoking was reported by 22%, and 38% were ex-smokers. Ever smokers experienced poorer BASDAI (β = 0.5; 0.2 to 0.9) and BASFI (β = 0.8; 0.4 to 1.2), and reported worse QoL (ASQoL, β = 1.5; 0.7 to 2.3). Compared to current smokers, ex-smokers reported lower disease activity (BASDAI, β = -0.5; -1.0 to -0.04) and significantly better QoL (ASQoL, β = -1.2; -2.3 to -0.2). They also were more likely to have a uveitis history (OR = 2.4; 1.5 to 3.8). Conclusions Smokers with spondyloarthritis experience worse disease than never smokers. However, we provide new evidence that, among smokers, smoking cessation is associated with lower disease activity and better physical function and QoL. Clinicians should specifically promote smoking cessation as an adjunct to usual therapy in patients with spondyloarthritis. This article is protected by copyright. All rights reserved.

  17. Reticence, Accuracy and Efficacy

    NASA Astrophysics Data System (ADS)

    Oreskes, N.; Lewandowsky, S.

    2015-12-01

    James Hansen has cautioned the scientific community against "reticence," by which he means a reluctance to speak in public about the threat of climate change. This may contribute to social inaction, with the result that society fails to respond appropriately to threats that are well understood scientifically. Against this, others have warned against the dangers of "crying wolf," suggesting that reticence protects scientific credibility. We argue that both these positions are missing an important point: that reticence is not only a matter of style but also of substance. In previous work, Bysse et al. (2013) showed that scientific projections of key indicators of climate change have been skewed towards the low end of actual events, suggesting a bias in scientific work. More recently, we have shown that scientific efforts to be responsive to contrarian challenges have led scientists to adopt the terminology of a "pause" or "hiatus" in climate warming, despite the lack of evidence to support such a conclusion (Lewandowsky et al., 2015a. 2015b). In the former case, scientific conservatism has led to under-estimation of climate related changes. In the latter case, the use of misleading terminology has perpetuated scientific misunderstanding and hindered effective communication. Scientific communication should embody two equally important goals: 1) accuracy in communicating scientific information and 2) efficacy in expressing what that information means. Scientists should strive to be neither conservative nor adventurous but to be accurate, and to communicate that accurate information effectively.

  18. C13 urea breath test accuracy analysis against former C14 urea breath test technique: is there still a need for an indeterminate result category?

    PubMed

    Charest, Mathieu; Belair, Marc-Andre

    2017-03-09

    Helicobacter pylori (H. Pylori) infection is the leading cause of peptic ulcer disease. Purpose: To assess the difference in distribution of negative versus positive breath test results between the former C14 urea breath test (UBT) and the newer C13 UBT. Second, to determine if the use of an indeterminate category is still meaningful and what type of results should trigger a repeat testing. Methods: Retrospective survey was performed of all consecutive patients referred to our service for a UBT. We analysed 562 patients with C14 UBT and 454 patients with C13 UBT. Results: C13 negative results are distributed farther away from the cut-off value and grouped more tightly around the mean negative value, as compare to the more widely distributed C14 negative results. Distribution analysis of the negative results of the C13 UBT compare to the negative results of the C14 UBT reveals a statistically significant difference. Within the C13 UBT group, only 1 patient could have been classify as having an indeterminate result using the same indeterminate zone previously used with C14 UBT. This is significantly less frequent than what was previously found with C14 UBT. Discussion: Borderline negative result do occurs with C13 UBT, although less frequently then with the C14 UBT, and we will carefully monitored results falling between 3.0 and 3.5 %delta. C13 UBTis a safe and simple test for the patient, provides a clearer positive or negative test results for the clinician in the majority of cases.

  19. "First Things First" Shows Promising Results

    ERIC Educational Resources Information Center

    Hendrie, Caroline

    2005-01-01

    In this article, the author discusses a school improvement model, First Things First, developed by James P. Connell, a former tenured professor of psychology at the University of Rochester in New York. The model has three pillars for the high school level: (1) small, themed learning communities that each keep a group of students together…

  20. Results.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

  1. Initial results of efficacy and safety of Sofosbuvir among Pakistani Population: A real life trial - Hepatitis Eradication Accuracy Trial of Sofosbuvir (HEATS)

    PubMed Central

    Azam, Zahid; Shoaib, Muhammad; Javed, Masood; Sarwar, Muhammad Adnan; Shaikh, Hafeezullah; Khokhar, Nasir

    2017-01-01

    Objective: The uridine nucleotide analogue sofosbuvir is a selective inhibitor of hepatitis C virus (HCV) NS5B polymerase approved for the treatment of chronic HCV infection with genotypes 1 – 4. The objective of the study was to evaluate the interim results of efficacy and safety of regimens containing Sofosbuvir (Zoval) among Pakistani population with the rapid virologic response (RVR2/4 weeks) with HCV infections. Methods: This is a multicenter open label prospective observational study. Patients suffering from chronic Hepatitis C infection received Sofosbuvir (Zoval) 400 mg plus ribavirin (with or without peg interferon) for 12/24 weeks. The interim results of this study were rapid virological response on week 4. Data was analyzed using SPSS version 21 for descriptive statistics. Results: A total of 573 patients with HCV infection were included in the study. The mean age of patients was 46.07 ± 11.41 years. Out of 573 patients 535 (93.3%) were treatment naive, 26 (4.5%) were relapser, 7 (1.2%) were non-responders and 5 (1.0%) were partial responders. A rapid virologic response was reported in 563(98.2%) of patients with HCV infection after four weeks of treatment. The treatment was generally well tolerated. Conclusion: Sofosbuvir (Zoval) is effective and well tolerated in combination with ribavirin in HCV infected patients. PMID:28367171

  2. Accuracy of perturbative master equations.

    PubMed

    Fleming, C H; Cummings, N I

    2011-03-01

    We consider open quantum systems with dynamics described by master equations that have perturbative expansions in the system-environment interaction. We show that, contrary to intuition, full-time solutions of order-2n accuracy require an order-(2n+2) master equation. We give two examples of such inaccuracies in the solutions to an order-2n master equation: order-2n inaccuracies in the steady state of the system and order-2n positivity violations. We show how these arise in a specific example for which exact solutions are available. This result has a wide-ranging impact on the validity of coupling (or friction) sensitive results derived from second-order convolutionless, Nakajima-Zwanzig, Redfield, and Born-Markov master equations.

  3. Glioma residual or recurrence versus radiation necrosis: accuracy of pentavalent technetium-99m-dimercaptosuccinic acid [Tc-99m (V) DMSA] brain SPECT compared to proton magnetic resonance spectroscopy (1H-MRS): initial results.

    PubMed

    Amin, Amr; Moustafa, Hosna; Ahmed, Ebaa; El-Toukhy, Mohamed

    2012-02-01

    We compared pentavalent technetium-99m dimercaptosuccinic acid (Tc-99m (V) DMSA) brain single photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy ((1)H-MRS) for the detection of residual or recurrent gliomas after surgery and radiotherapy. A total of 24 glioma patients, previously operated upon and treated with radiotherapy, were studied. SPECT was acquired 2-3 h post-administration of 555-740 MBq of Tc-99m (V) DMSA. Lesion to normal (L/N) delayed uptake ratio was calculated as: mean counts of tumor ROI (L)/mean counts of normal mirror symmetric ROI (N). (1)H-MRS was performed using a 1.5-T scanner equipped with a spectroscopy package. SPECT and (1)H-MRS results were compared with pathology or follow-up neuroimaging studies. SPECT and (1)H-MRS showed concordant residue or recurrence in 9/24 (37.5%) patients. Both were true negative in 6/24 (25%) patients. SPECT and (1)H-MRS disagreed in 9 recurrences [7/9 (77.8%) and 2/9 (22.2%) were true positive by SPECT and (1)H-MRS, respectively]. Sensitivity of SPECT and (1)H-MRS in detecting recurrence was 88.8 and 61.1% with accuracies of 91.6 and 70.8%, respectively. A positive association between the delayed L/N ratio and tumor grade was found; the higher the grade, the higher is the L/N ratio (r = 0.62, P = 0.001). Tc-99m (V) DMSA brain SPECT is more accurate compared to (1)H-MRS for the detection of tumor residual tissues or recurrence in glioma patients with previous radiotherapy. It allows early and non-invasive differentiation of residual tumor or recurrence from irradiation necrosis.

  4. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

    Results from operational OD produced by the NASA Goddard Flight Dynamics Facility for the LRO nominal and extended mission are presented. During the LRO nominal mission, when LRO flew in a low circular orbit, orbit determination requirements were met nearly 100% of the time. When the extended mission began, LRO returned to a more elliptical frozen orbit where gravity and other modeling errors caused numerous violations of mission accuracy requirements. Prediction accuracy is particularly challenged during periods when LRO is in full-Sun. A series of improvements to LRO orbit determination are presented, including implementation of new lunar gravity models, improved spacecraft solar radiation pressure modeling using a dynamic multi-plate area model, a shorter orbit determination arc length, and a constrained plane method for estimation. The analysis presented in this paper shows that updated lunar gravity models improved accuracy in the frozen orbit, and a multiplate dynamic area model improves prediction accuracy during full-Sun orbit periods. Implementation of a 36-hour tracking data arc and plane constraints during edge-on orbit geometry also provide benefits. A comparison of the operational solutions to precision orbit determination solutions shows agreement on a 100- to 250-meter level in definitive accuracy.

  5. The measurement accuracy of passive radon instruments.

    PubMed

    Beck, T R; Foerster, E; Buchröder, H; Schmidt, V; Döring, J

    2014-01-01

    This paper analyses the data having been gathered from interlaboratory comparisons of passive radon instruments over 10 y with respect to the measurement accuracy. The measurement accuracy is discussed in terms of the systematic and the random measurement error. The analysis shows that the systematic measurement error of the most instruments issued by professional laboratory services can be within a range of ±10 % from the true value. A single radon measurement has an additional random measurement error, which is in the range of up to ±15 % for high exposures to radon (>2000 kBq h m(-3)). The random measurement error increases for lower exposures. The analysis especially applies to instruments with solid-state nuclear track detectors and results in proposing criteria for testing the measurement accuracy. Instruments with electrets and charcoal have also been considered, but the low stock of data enables only a qualitative discussion.

  6. High accuracy time transfer synchronization

    NASA Technical Reports Server (NTRS)

    Wheeler, Paul J.; Koppang, Paul A.; Chalmers, David; Davis, Angela; Kubik, Anthony; Powell, William M.

    1995-01-01

    In July 1994, the U.S. Naval Observatory (USNO) Time Service System Engineering Division conducted a field test to establish a baseline accuracy for two-way satellite time transfer synchronization. Three Hewlett-Packard model 5071 high performance cesium frequency standards were transported from the USNO in Washington, DC to Los Angeles, California in the USNO's mobile earth station. Two-Way Satellite Time Transfer links between the mobile earth station and the USNO were conducted each day of the trip, using the Naval Research Laboratory(NRL) designed spread spectrum modem, built by Allen Osborne Associates(AOA). A Motorola six channel GPS receiver was used to track the location and altitude of the mobile earth station and to provide coordinates for calculating Sagnac corrections for the two-way measurements, and relativistic corrections for the cesium clocks. This paper will discuss the trip, the measurement systems used and the results from the data collected. We will show the accuracy of using two-way satellite time transfer for synchronization and the performance of the three HP 5071 cesium clocks in an operational environment.

  7. A fast RCS accuracy assessment method for passive radar calibrators

    NASA Astrophysics Data System (ADS)

    Zhou, Yongsheng; Li, Chuanrong; Tang, Lingli; Ma, Lingling; Liu, QI

    2016-10-01

    In microwave radar radiometric calibration, the corner reflector acts as the standard reference target but its structure is usually deformed during the transportation and installation, or deformed by wind and gravity while permanently installed outdoor, which will decrease the RCS accuracy and therefore the radiometric calibration accuracy. A fast RCS accuracy measurement method based on 3-D measuring instrument and RCS simulation was proposed in this paper for tracking the characteristic variation of the corner reflector. In the first step, RCS simulation algorithm was selected and its simulation accuracy was assessed. In the second step, the 3-D measuring instrument was selected and its measuring accuracy was evaluated. Once the accuracy of the selected RCS simulation algorithm and 3-D measuring instrument was satisfied for the RCS accuracy assessment, the 3-D structure of the corner reflector would be obtained by the 3-D measuring instrument, and then the RCSs of the obtained 3-D structure and corresponding ideal structure would be calculated respectively based on the selected RCS simulation algorithm. The final RCS accuracy was the absolute difference of the two RCS calculation results. The advantage of the proposed method was that it could be applied outdoor easily, avoiding the correlation among the plate edge length error, plate orthogonality error, plate curvature error. The accuracy of this method is higher than the method using distortion equation. In the end of the paper, a measurement example was presented in order to show the performance of the proposed method.

  8. 100% Classification Accuracy Considered Harmful: The Normalized Information Transfer Factor Explains the Accuracy Paradox

    PubMed Central

    Valverde-Albacete, Francisco J.; Peláez-Moreno, Carmen

    2014-01-01

    The most widely spread measure of performance, accuracy, suffers from a paradox: predictive models with a given level of accuracy may have greater predictive power than models with higher accuracy. Despite optimizing classification error rate, high accuracy models may fail to capture crucial information transfer in the classification task. We present evidence of this behavior by means of a combinatorial analysis where every possible contingency matrix of 2, 3 and 4 classes classifiers are depicted on the entropy triangle, a more reliable information-theoretic tool for classification assessment. Motivated by this, we develop from first principles a measure of classification performance that takes into consideration the information learned by classifiers. We are then able to obtain the entropy-modulated accuracy (EMA), a pessimistic estimate of the expected accuracy with the influence of the input distribution factored out, and the normalized information transfer factor (NIT), a measure of how efficient is the transmission of information from the input to the output set of classes. The EMA is a more natural measure of classification performance than accuracy when the heuristic to maximize is the transfer of information through the classifier instead of classification error count. The NIT factor measures the effectiveness of the learning process in classifiers and also makes it harder for them to “cheat” using techniques like specialization, while also promoting the interpretability of results. Their use is demonstrated in a mind reading task competition that aims at decoding the identity of a video stimulus based on magnetoencephalography recordings. We show how the EMA and the NIT factor reject rankings based in accuracy, choosing more meaningful and interpretable classifiers. PMID:24427282

  9. 100% classification accuracy considered harmful: the normalized information transfer factor explains the accuracy paradox.

    PubMed

    Valverde-Albacete, Francisco J; Peláez-Moreno, Carmen

    2014-01-01

    The most widely spread measure of performance, accuracy, suffers from a paradox: predictive models with a given level of accuracy may have greater predictive power than models with higher accuracy. Despite optimizing classification error rate, high accuracy models may fail to capture crucial information transfer in the classification task. We present evidence of this behavior by means of a combinatorial analysis where every possible contingency matrix of 2, 3 and 4 classes classifiers are depicted on the entropy triangle, a more reliable information-theoretic tool for classification assessment. Motivated by this, we develop from first principles a measure of classification performance that takes into consideration the information learned by classifiers. We are then able to obtain the entropy-modulated accuracy (EMA), a pessimistic estimate of the expected accuracy with the influence of the input distribution factored out, and the normalized information transfer factor (NIT), a measure of how efficient is the transmission of information from the input to the output set of classes. The EMA is a more natural measure of classification performance than accuracy when the heuristic to maximize is the transfer of information through the classifier instead of classification error count. The NIT factor measures the effectiveness of the learning process in classifiers and also makes it harder for them to "cheat" using techniques like specialization, while also promoting the interpretability of results. Their use is demonstrated in a mind reading task competition that aims at decoding the identity of a video stimulus based on magnetoencephalography recordings. We show how the EMA and the NIT factor reject rankings based in accuracy, choosing more meaningful and interpretable classifiers.

  10. Effects of accuracy motivation and anchoring on metacomprehension judgment and accuracy.

    PubMed

    Zhao, Qin

    2012-01-01

    The current research investigates how accuracy motivation impacts anchoring and adjustment in metacomprehension judgment and how accuracy motivation and anchoring affect metacomprehension accuracy. Participants were randomly assigned to one of six conditions produced by the between-subjects factorial design involving accuracy motivation (incentive or no) and peer performance anchor (95%, 55%, or no). Two studies showed that accuracy motivation did not impact anchoring bias, but the adjustment-from-anchor process occurred. Accuracy incentive increased anchor-judgment gap for the 95% anchor but not for the 55% anchor, which induced less certainty about the direction of adjustment. The findings offer support to the integrative theory of anchoring. Additionally, the two studies revealed a "power struggle" between accuracy motivation and anchoring in influencing metacomprehension accuracy. Accuracy motivation could improve metacomprehension accuracy in spite of anchoring effect, but if anchoring effect is too strong, it could overpower the motivation effect. The implications of the findings were discussed.

  11. Modeling individual differences in response time and accuracy in numeracy.

    PubMed

    Ratcliff, Roger; Thompson, Clarissa A; McKoon, Gail

    2015-04-01

    In the study of numeracy, some hypotheses have been based on response time (RT) as a dependent variable and some on accuracy, and considerable controversy has arisen about the presence or absence of correlations between RT and accuracy, between RT or accuracy and individual differences like IQ and math ability, and between various numeracy tasks. In this article, we show that an integration of the two dependent variables is required, which we accomplish with a theory-based model of decision making. We report data from four tasks: numerosity discrimination, number discrimination, memory for two-digit numbers, and memory for three-digit numbers. Accuracy correlated across tasks, as did RTs. However, the negative correlations that might be expected between RT and accuracy were not obtained; if a subject was accurate, it did not mean that they were fast (and vice versa). When the diffusion decision-making model was applied to the data (Ratcliff, 1978), we found significant correlations across the tasks between the quality of the numeracy information (drift rate) driving the decision process and between the speed/accuracy criterion settings, suggesting that similar numeracy skills and similar speed-accuracy settings are involved in the four tasks. In the model, accuracy is related to drift rate and RT is related to speed-accuracy criteria, but drift rate and criteria are not related to each other across subjects. This provides a theoretical basis for understanding why negative correlations were not obtained between accuracy and RT. We also manipulated criteria by instructing subjects to maximize either speed or accuracy, but still found correlations between the criteria settings between and within tasks, suggesting that the settings may represent an individual trait that can be modulated but not equated across subjects. Our results demonstrate that a decision-making model may provide a way to reconcile inconsistent and sometimes contradictory results in numeracy

  12. Accuracy of a new patch pump based on a microelectromechanical system (MEMS) compared to other commercially available insulin pumps: results of the first in vitro and in vivo studies.

    PubMed

    Borot, Sophie; Franc, Sylvia; Cristante, Justine; Penfornis, Alfred; Benhamou, Pierre-Yves; Guerci, Bruno; Hanaire, Hélène; Renard, Eric; Reznik, Yves; Simon, Chantal; Charpentier, Guillaume

    2014-11-01

    The JewelPUMP™ (JP) is a new patch pump based on a microelectromechanical system that operates without any plunger. The study aimed to evaluate the infusion accuracy of the JP in vitro and in vivo. For the in vitro studies, commercially available pumps meeting the ISO standard were compared to the JP: the MiniMed® Paradigm® 712 (MP), Accu-Chek® Combo (AC), OmniPod® (OP), Animas® Vibe™ (AN). Pump accuracy was measured over 24 hours using a continuous microweighing method, at 0.1 and 1 IU/h basal rates. The occlusion alarm threshold was measured after a catheter occlusion. The JP, filled with physiological serum, was then tested in 13 patients with type 1 diabetes simultaneously with their own pump for 2 days. The weight difference was used to calculate the infused insulin volume. The JP showed reduced absolute median error rate in vitro over a 15-minute observation window compared to other pumps (1 IU/h): ±1.02% (JP) vs ±1.60% (AN), ±1.66% (AC), ±2.22% (MP), and ±4.63% (OP), P < .0001. But there was no difference over 24 hours. At 0.5 IU/h, the JP was able to detect an occlusion earlier than other pumps: 21 (19; 25) minutes vs 90 (85; 95), 58 (42; 74), and 143 (132; 218) minutes (AN, AC, MP), P < .05 vs AN and MP. In patients, the 24-hour flow error was not significantly different between the JP and usual pumps (-2.2 ± 5.6% vs -0.37 ± 4.0%, P = .25). The JP was found to be easier to wear than conventional pumps. The JP is more precise over a short time period, more sensitive to catheter occlusion, well accepted by patients, and consequently, of potential interest for a closed-loop insulin delivery system.

  13. Bullet trajectory reconstruction - Methods, accuracy and precision.

    PubMed

    Mattijssen, Erwin J A T; Kerkhoff, Wim

    2016-05-01

    Based on the spatial relation between a primary and secondary bullet defect or on the shape and dimensions of the primary bullet defect, a bullet's trajectory prior to impact can be estimated for a shooting scene reconstruction. The accuracy and precision of the estimated trajectories will vary depending on variables such as, the applied method of reconstruction, the (true) angle of incidence, the properties of the target material and the properties of the bullet upon impact. This study focused on the accuracy and precision of estimated bullet trajectories when different variants of the probing method, ellipse method, and lead-in method are applied on bullet defects resulting from shots at various angles of incidence on drywall, MDF and sheet metal. The results show that in most situations the best performance (accuracy and precision) is seen when the probing method is applied. Only for the lowest angles of incidence the performance was better when either the ellipse or lead-in method was applied. The data provided in this paper can be used to select the appropriate method(s) for reconstruction and to correct for systematic errors (accuracy) and to provide a value of the precision, by means of a confidence interval of the specific measurement.

  14. A study of laseruler accuracy and precision (1986-1987)

    SciTech Connect

    Ramachandran, R.S.; Armstrong, K.P.

    1989-06-22

    A study was conducted to investigate Laserruler accuracy and precision. Tests were performed on 0.050 in., 0.100 in., and 0.120 in. gauge block standards. Results showed and accuracy of 3.7 {mu}in. for the 0.12 in. standard, with higher accuracies for the two thinner blocks. The Laserruler precision was 4.83 {mu}in. for the 0.120 in. standard, 3.83 {mu}in. for the 0.100 in. standard, and 4.2 {mu}in. for the 0.050 in. standard.

  15. Camera Calibration Accuracy at Different Uav Flying Heights

    NASA Astrophysics Data System (ADS)

    Yusoff, A. R.; Ariff, M. F. M.; Idris, K. M.; Majid, Z.; Chong, A. K.

    2017-02-01

    Unmanned Aerial Vehicles (UAVs) can be used to acquire highly accurate data in deformation survey, whereby low-cost digital cameras are commonly used in the UAV mapping. Thus, camera calibration is considered important in obtaining high-accuracy UAV mapping using low-cost digital cameras. The main focus of this study was to calibrate the UAV camera at different camera distances and check the measurement accuracy. The scope of this study included camera calibration in the laboratory and on the field, and the UAV image mapping accuracy assessment used calibration parameters of different camera distances. The camera distances used for the image calibration acquisition and mapping accuracy assessment were 1.5 metres in the laboratory, and 15 and 25 metres on the field using a Sony NEX6 digital camera. A large calibration field and a portable calibration frame were used as the tools for the camera calibration and for checking the accuracy of the measurement at different camera distances. Bundle adjustment concept was applied in Australis software to perform the camera calibration and accuracy assessment. The results showed that the camera distance at 25 metres is the optimum object distance as this is the best accuracy obtained from the laboratory as well as outdoor mapping. In conclusion, the camera calibration at several camera distances should be applied to acquire better accuracy in mapping and the best camera parameter for the UAV image mapping should be selected for highly accurate mapping measurement.

  16. When Does Choice of Accuracy Measure Alter Imputation Accuracy Assessments?

    PubMed Central

    Ramnarine, Shelina; Zhang, Juan; Chen, Li-Shiun; Culverhouse, Robert; Duan, Weimin; Hancock, Dana B.; Hartz, Sarah M.; Johnson, Eric O.; Olfson, Emily; Schwantes-An, Tae-Hwi; Saccone, Nancy L.

    2015-01-01

    Imputation, the process of inferring genotypes for untyped variants, is used to identify and refine genetic association findings. Inaccuracies in imputed data can distort the observed association between variants and a disease. Many statistics are used to assess accuracy; some compare imputed to genotyped data and others are calculated without reference to true genotypes. Prior work has shown that the Imputation Quality Score (IQS), which is based on Cohen’s kappa statistic and compares imputed genotype probabilities to true genotypes, appropriately adjusts for chance agreement; however, it is not commonly used. To identify differences in accuracy assessment, we compared IQS with concordance rate, squared correlation, and accuracy measures built into imputation programs. Genotypes from the 1000 Genomes reference populations (AFR N = 246 and EUR N = 379) were masked to match the typed single nucleotide polymorphism (SNP) coverage of several SNP arrays and were imputed with BEAGLE 3.3.2 and IMPUTE2 in regions associated with smoking behaviors. Additional masking and imputation was conducted for sequenced subjects from the Collaborative Genetic Study of Nicotine Dependence and the Genetic Study of Nicotine Dependence in African Americans (N = 1,481 African Americans and N = 1,480 European Americans). Our results offer further evidence that concordance rate inflates accuracy estimates, particularly for rare and low frequency variants. For common variants, squared correlation, BEAGLE R2, IMPUTE2 INFO, and IQS produce similar assessments of imputation accuracy. However, for rare and low frequency variants, compared to IQS, the other statistics tend to be more liberal in their assessment of accuracy. IQS is important to consider when evaluating imputation accuracy, particularly for rare and low frequency variants. PMID:26458263

  17. Improving Speaking Accuracy through Awareness

    ERIC Educational Resources Information Center

    Dormer, Jan Edwards

    2013-01-01

    Increased English learner accuracy can be achieved by leading students through six stages of awareness. The first three awareness stages build up students' motivation to improve, and the second three provide learners with crucial input for change. The final result is "sustained language awareness," resulting in ongoing…

  18. Thematic accuracy of the NLCD 2001 land cover for the conterminous United States

    USGS Publications Warehouse

    Wickham, J.D.; Stehman, S.V.; Fry, J.A.; Smith, J.H.; Homer, C.G.

    2010-01-01

    The land-cover thematic accuracy of NLCD 2001 was assessed from a probability-sample of 15,000 pixels. Nationwide, NLCD 2001 overall Anderson Level II and Level I accuracies were 78.7% and 85.3%, respectively. By comparison, overall accuracies at Level II and Level I for the NLCD 1992 were 58% and 80%. Forest and cropland were two classes showing substantial improvements in accuracy in NLCD 2001 relative to NLCD 1992. NLCD 2001 forest and cropland user's accuracies were 87% and 82%, respectively, compared to 80% and 43% for NLCD 1992. Accuracy results are reported for 10 geographic regions of the United States, with regional overall accuracies ranging from 68% to 86% for Level II and from 79% to 91% at Level I. Geographic variation in class-specific accuracy was strongly associated with the phenomenon that regionally more abundant land-cover classes had higher accuracy. Accuracy estimates based on several definitions of agreement are reported to provide an indication of the potential impact of reference data error on accuracy. Drawing on our experience from two NLCD national accuracy assessments, we discuss the use of designs incorporating auxiliary data to more seamlessly quantify reference data quality as a means to further advance thematic map accuracy assessment.

  19. Effects of cognitive training on change in accuracy in inductive reasoning ability.

    PubMed

    Boron, Julie Blaskewicz; Turiano, Nicholas A; Willis, Sherry L; Schaie, K Warner

    2007-05-01

    We investigated cognitive training effects on accuracy and number of items attempted in inductive reasoning performance in a sample of 335 older participants (M = 72.78 years) from the Seattle Longitudinal Study. We assessed the impact of individual characteristics, including chronic disease. The reasoning training group showed significantly greater gain in accuracy and number of attempted items than did the comparison group; gain was primarily due to enhanced accuracy. Reasoning training effects involved a complex interaction of gender, prior cognitive status, and chronic disease. Women with prior decline on reasoning but no heart disease showed the greatest accuracy increase. In addition, stable reasoning-trained women with heart disease demonstrated significant accuracy gain. Comorbidity was associated with less change in accuracy. The results support the effectiveness of cognitive training on improving the accuracy of reasoning performance.

  20. GEOSPATIAL DATA ACCURACY ASSESSMENT

    EPA Science Inventory

    The development of robust accuracy assessment methods for the validation of spatial data represent's a difficult scientific challenge for the geospatial science community. The importance and timeliness of this issue is related directly to the dramatic escalation in the developmen...

  1. Landsat wildland mapping accuracy

    USGS Publications Warehouse

    Todd, William J.; Gehring, Dale G.; Haman, J. F.

    1980-01-01

    A Landsat-aided classification of ten wildland resource classes was developed for the Shivwits Plateau region of the Lake Mead National Recreation Area. Single stage cluster sampling (without replacement) was used to verify the accuracy of each class.

  2. Accuracy of forecasts in strategic intelligence.

    PubMed

    Mandel, David R; Barnes, Alan

    2014-07-29

    The accuracy of 1,514 strategic intelligence forecasts abstracted from intelligence reports was assessed. The results show that both discrimination and calibration of forecasts was very good. Discrimination was better for senior (versus junior) analysts and for easier (versus harder) forecasts. Miscalibration was mainly due to underconfidence such that analysts assigned more uncertainty than needed given their high level of discrimination. Underconfidence was more pronounced for harder (versus easier) forecasts and for forecasts deemed more (versus less) important for policy decision making. Despite the observed underconfidence, there was a paucity of forecasts in the least informative 0.4-0.6 probability range. Recalibrating the forecasts substantially reduced underconfidence. The findings offer cause for tempered optimism about the accuracy of strategic intelligence forecasts and indicate that intelligence producers aim to promote informativeness while avoiding overstatement.

  3. Positional Accuracy Assessment of Googleearth in Riyadh

    NASA Astrophysics Data System (ADS)

    Farah, Ashraf; Algarni, Dafer

    2014-06-01

    Google Earth is a virtual globe, map and geographical information program that is controlled by Google corporation. It maps the Earth by the superimposition of images obtained from satellite imagery, aerial photography and GIS 3D globe. With millions of users all around the globe, GoogleEarth® has become the ultimate source of spatial data and information for private and public decision-support systems besides many types and forms of social interactions. Many users mostly in developing countries are also using it for surveying applications, the matter that raises questions about the positional accuracy of the Google Earth program. This research presents a small-scale assessment study of the positional accuracy of GoogleEarth® Imagery in Riyadh; capital of Kingdom of Saudi Arabia (KSA). The results show that the RMSE of the GoogleEarth imagery is 2.18 m and 1.51 m for the horizontal and height coordinates respectively.

  4. Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units.

    PubMed

    Cai, Qingzhong; Yang, Gongliu; Song, Ningfang; Liu, Yiliang

    2016-06-22

    An inertial navigation system (INS) has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10(-6)°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs) using common turntables, has a great application potential in future atomic gyro INSs.

  5. Accuracy Assessment of Coastal Topography Derived from Uav Images

    NASA Astrophysics Data System (ADS)

    Long, N.; Millescamps, B.; Pouget, F.; Dumon, A.; Lachaussée, N.; Bertin, X.

    2016-06-01

    To monitor coastal environments, Unmanned Aerial Vehicle (UAV) is a low-cost and easy to use solution to enable data acquisition with high temporal frequency and spatial resolution. Compared to Light Detection And Ranging (LiDAR) or Terrestrial Laser Scanning (TLS), this solution produces Digital Surface Model (DSM) with a similar accuracy. To evaluate the DSM accuracy on a coastal environment, a campaign was carried out with a flying wing (eBee) combined with a digital camera. Using the Photoscan software and the photogrammetry process (Structure From Motion algorithm), a DSM and an orthomosaic were produced. Compared to GNSS surveys, the DSM accuracy is estimated. Two parameters are tested: the influence of the methodology (number and distribution of Ground Control Points, GCPs) and the influence of spatial image resolution (4.6 cm vs 2 cm). The results show that this solution is able to reproduce the topography of a coastal area with a high vertical accuracy (< 10 cm). The georeferencing of the DSM require a homogeneous distribution and a large number of GCPs. The accuracy is correlated with the number of GCPs (use 19 GCPs instead of 10 allows to reduce the difference of 4 cm); the required accuracy should be dependant of the research problematic. Last, in this particular environment, the presence of very small water surfaces on the sand bank does not allow to improve the accuracy when the spatial resolution of images is decreased.

  6. Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units

    PubMed Central

    Cai, Qingzhong; Yang, Gongliu; Song, Ningfang; Liu, Yiliang

    2016-01-01

    An inertial navigation system (INS) has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10−6°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs) using common turntables, has a great application potential in future atomic gyro INSs. PMID:27338408

  7. Spacecraft attitude determination accuracy from mission experience

    NASA Astrophysics Data System (ADS)

    Brasoveanu, D.; Hashmall, J.; Baker, D.

    1994-10-01

    This document presents a compilation of the attitude accuracy attained by a number of satellites that have been supported by the Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC). It starts with a general description of the factors that influence spacecraft attitude accuracy. After brief descriptions of the missions supported, it presents the attitude accuracy results for currently active and older missions, including both three-axis stabilized and spin-stabilized spacecraft. The attitude accuracy results are grouped by the sensor pair used to determine the attitudes. A supplementary section is also included, containing the results of theoretical computations of the effects of variation of sensor accuracy on overall attitude accuracy.

  8. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, D.; Hashmall, J.; Baker, D.

    1994-01-01

    This document presents a compilation of the attitude accuracy attained by a number of satellites that have been supported by the Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC). It starts with a general description of the factors that influence spacecraft attitude accuracy. After brief descriptions of the missions supported, it presents the attitude accuracy results for currently active and older missions, including both three-axis stabilized and spin-stabilized spacecraft. The attitude accuracy results are grouped by the sensor pair used to determine the attitudes. A supplementary section is also included, containing the results of theoretical computations of the effects of variation of sensor accuracy on overall attitude accuracy.

  9. A high accuracy sun sensor

    NASA Astrophysics Data System (ADS)

    Bokhove, H.

    The High Accuracy Sun Sensor (HASS) is described, concentrating on measurement principle, the CCD detector used, the construction of the sensorhead and the operation of the sensor electronics. Tests on a development model show that the main aim of a 0.01-arcsec rms stability over a 10-minute period is closely approached. Remaining problem areas are associated with the sensor sensitivity to illumination level variations, the shielding of the detector, and the test and calibration equipment.

  10. Public medical shows.

    PubMed

    Walusinski, Olivier

    2014-01-01

    In the second half of the 19th century, Jean-Martin Charcot (1825-1893) became famous for the quality of his teaching and his innovative neurological discoveries, bringing many French and foreign students to Paris. A hunger for recognition, together with progressive and anticlerical ideals, led Charcot to invite writers, journalists, and politicians to his lessons, during which he presented the results of his work on hysteria. These events became public performances, for which physicians and patients were transformed into actors. Major newspapers ran accounts of these consultations, more like theatrical shows in some respects. The resultant enthusiasm prompted other physicians in Paris and throughout France to try and imitate them. We will compare the form and substance of Charcot's lessons with those given by Jules-Bernard Luys (1828-1897), Victor Dumontpallier (1826-1899), Ambroise-Auguste Liébault (1823-1904), Hippolyte Bernheim (1840-1919), Joseph Grasset (1849-1918), and Albert Pitres (1848-1928). We will also note their impact on contemporary cinema and theatre.

  11. Accuracy of Stokes integration for geoid computation

    NASA Astrophysics Data System (ADS)

    Ismail, Zahra; Jamet, Olivier; Altamimi, Zuheir

    2014-05-01

    Geoid determination by remove-compute-restore (RCR) technique involves the application of Stokes's integral on reduced gravity anomalies. Reduced gravity anomalies are obtained through interpolation after removing low degree gravity signal from space spherical harmonic model and high frequency from topographical effects and cover a spectre ranging from degree 150-200. Stokes's integral is truncated to a limited region around the computation point producing an error that will be reducing by a modification of Stokes's kernel. We study Stokes integral accuracy on synthetic signal of various frequency ranges, produced with EGM2008 spherical harmonic coefficients up to degree 2000. We analyse the integration error according to the frequency range of signal, the resolution of gravity anomaly grid and the radius of Stokes integration. The study shows that the behaviour of the relative errors is frequency independent. The standard Stokes kernel is though insufficient to produce 1cm geoid accuracy without a removal of the major part of the gravity signal up to degree 600. The Integration over an area of radius greater than 3 degree does not improve accuracy improvement. The results are compared to a similar experiment using the modified Stokes kernel formula (Ellmann2004, Sjöberg2003). References: Ellmann, A. (2004) The geoid for the Baltic countries determined by least-squares modification of Stokes formula. Sjöberg, LE (2003). A general model of modifying Stokes formula and its least-squares solution Journal of Geodesy, 77. 459-464.

  12. Haptic perception accuracy depending on self-produced movement.

    PubMed

    Park, Chulwook; Kim, Seonjin

    2014-01-01

    This study measured whether self-produced movement influences haptic perception ability (experiment 1) as well as the factors associated with levels of influence (experiment 2) in racket sports. For experiment 1, the haptic perception accuracy levels of five male table tennis experts and five male novices were examined under two different conditions (no movement vs. movement). For experiment 2, the haptic afferent subsystems of five male table tennis experts and five male novices were investigated in only the self-produced movement-coupled condition. Inferential statistics (ANOVA, t-test) and custom-made devices (shock & vibration sensor, Qualisys Track Manager) of the data were used to determine the haptic perception accuracy (experiment 1, experiment 2) and its association with expertise. The results of this research show that expert-level players acquire higher accuracy with less variability (racket vibration and angle) than novice-level players, especially in their self-produced movement coupled performances. The important finding from this result is that, in terms of accuracy, the skill-associated differences were enlarged during self-produced movement. To explain the origin of this difference between experts and novices, the functional variability of haptic afferent subsystems can serve as a reference. These two factors (self-produced accuracy and the variability of haptic features) as investigated in this study would be useful criteria for educators in racket sports and suggest a broader hypothesis for further research into the effects of the haptic accuracy related to variability.

  13. Effects of Melodic Perception Instruction on Pitch Discrimination and Vocal Accuracy of Kindergarten Children.

    ERIC Educational Resources Information Center

    Apfelstadt, Hilary

    1984-01-01

    The E1 group was taught using visual and kinesthetic reinforcement; E2 using imitation; and C with a traditional, nonconceptual approach. Results showed no differences among groups in auditory discrimination, differences on vocal pitch-pattern accuracy between E1 and C and E2 and C, and differences in rote-singing accuracy between E2 and C.…

  14. Does aging impair first impression accuracy? Differentiating emotion recognition from complex social inferences.

    PubMed

    Krendl, Anne C; Rule, Nicholas O; Ambady, Nalini

    2014-09-01

    Young adults can be surprisingly accurate at making inferences about people from their faces. Although these first impressions have important consequences for both the perceiver and the target, it remains an open question whether first impression accuracy is preserved with age. Specifically, could age differences in impressions toward others stem from age-related deficits in accurately detecting complex social cues? Research on aging and impression formation suggests that young and older adults show relative consensus in their first impressions, but it is unknown whether they differ in accuracy. It has been widely shown that aging disrupts emotion recognition accuracy, and that these impairments may predict deficits in other social judgments, such as detecting deceit. However, it is unclear whether general impression formation accuracy (e.g., emotion recognition accuracy, detecting complex social cues) relies on similar or distinct mechanisms. It is important to examine this question to evaluate how, if at all, aging might affect overall accuracy. Here, we examined whether aging impaired first impression accuracy in predicting real-world outcomes and categorizing social group membership. Specifically, we studied whether emotion recognition accuracy and age-related cognitive decline (which has been implicated in exacerbating deficits in emotion recognition) predict first impression accuracy. Our results revealed that emotion recognition accuracy did not predict first impression accuracy, nor did age-related cognitive decline impair it. These findings suggest that domains of social perception outside of emotion recognition may rely on mechanisms that are relatively unimpaired by aging.

  15. Accuracy of flow hoods in residential applications

    SciTech Connect

    Wray, Craig P.; Walker, Iain S.; Sherman, Max H.

    2002-05-01

    To assess whether houses can meet performance expectations, the new practice of residential commissioning will likely use flow hoods to measure supply and return grille airflows in HVAC systems. Depending on hood accuracy, these measurements can be used to determine if individual rooms receive adequate airflow for heating and cooling, to determine flow imbalances between different building spaces, to estimate total air handler flow and supply/return imbalances, and to assess duct air leakage. This paper discusses these flow hood applications and the accuracy requirements in each case. Laboratory tests of several residential flow hoods showed that these hoods can be inadequate to measure flows in residential systems. Potential errors are about 20% to 30% of measured flow, due to poor calibrations, sensitivity to grille flow non-uniformities, and flow changes from added flow resistance. Active flow hoods equipped with measurement devices that are insensitive to grille airflow patterns have an order of magnitude less error, and are more reliable and consistent in most cases. Our tests also show that current calibration procedures for flow hoods do not account for field application problems. As a result, a new standard for flow hood calibration needs to be developed, along with a new measurement standard to address field use of flow hoods. Lastly, field evaluation of a selection of flow hoods showed that it is possible to obtain reasonable results using some flow hoods if the field tests are carefully done, the grilles are appropriate, and grille location does not restrict flow hood placement.

  16. Television Quiz Show Simulation

    ERIC Educational Resources Information Center

    Hill, Jonnie Lynn

    2007-01-01

    This article explores the simulation of four television quiz shows for students in China studying English as a foreign language (EFL). It discusses the adaptation and implementation of television quiz shows and how the students reacted to them.

  17. The Great Cometary Show

    NASA Astrophysics Data System (ADS)

    2007-01-01

    The ESO Very Large Telescope Interferometer, which allows astronomers to scrutinise objects with a precision equivalent to that of a 130-m telescope, is proving itself an unequalled success every day. One of the latest instruments installed, AMBER, has led to a flurry of scientific results, an anthology of which is being published this week as special features in the research journal Astronomy & Astrophysics. ESO PR Photo 06a/07 ESO PR Photo 06a/07 The AMBER Instrument "With its unique capabilities, the VLT Interferometer (VLTI) has created itself a niche in which it provide answers to many astronomical questions, from the shape of stars, to discs around stars, to the surroundings of the supermassive black holes in active galaxies," says Jorge Melnick (ESO), the VLT Project Scientist. The VLTI has led to 55 scientific papers already and is in fact producing more than half of the interferometric results worldwide. "With the capability of AMBER to combine up to three of the 8.2-m VLT Unit Telescopes, we can really achieve what nobody else can do," added Fabien Malbet, from the LAOG (France) and the AMBER Project Scientist. Eleven articles will appear this week in Astronomy & Astrophysics' special AMBER section. Three of them describe the unique instrument, while the other eight reveal completely new results about the early and late stages in the life of stars. ESO PR Photo 06b/07 ESO PR Photo 06b/07 The Inner Winds of Eta Carinae The first results presented in this issue cover various fields of stellar and circumstellar physics. Two papers deal with very young solar-like stars, offering new information about the geometry of the surrounding discs and associated outflowing winds. Other articles are devoted to the study of hot active stars of particular interest: Alpha Arae, Kappa Canis Majoris, and CPD -57o2874. They provide new, precise information about their rotating gas envelopes. An important new result concerns the enigmatic object Eta Carinae. Using AMBER with

  18. Arizona Vegetation Resource Inventory (AVRI) accuracy assessment

    USGS Publications Warehouse

    Szajgin, John; Pettinger, L.R.; Linden, D.S.; Ohlen, D.O.

    1982-01-01

    A quantitative accuracy assessment was performed for the vegetation classification map produced as part of the Arizona Vegetation Resource Inventory (AVRI) project. This project was a cooperative effort between the Bureau of Land Management (BLM) and the Earth Resources Observation Systems (EROS) Data Center. The objective of the accuracy assessment was to estimate (with a precision of ?10 percent at the 90 percent confidence level) the comission error in each of the eight level II hierarchical vegetation cover types. A stratified two-phase (double) cluster sample was used. Phase I consisted of 160 photointerpreted plots representing clusters of Landsat pixels, and phase II consisted of ground data collection at 80 of the phase I cluster sites. Ground data were used to refine the phase I error estimates by means of a linear regression model. The classified image was stratified by assigning each 15-pixel cluster to the stratum corresponding to the dominant cover type within each cluster. This method is known as stratified plurality sampling. Overall error was estimated to be 36 percent with a standard error of 2 percent. Estimated error for individual vegetation classes ranged from a low of 10 percent ?6 percent for evergreen woodland to 81 percent ?7 percent for cropland and pasture. Total cost of the accuracy assessment was $106,950 for the one-million-hectare study area. The combination of the stratified plurality sampling (SPS) method of sample allocation with double sampling provided the desired estimates within the required precision levels. The overall accuracy results confirmed that highly accurate digital classification of vegetation is difficult to perform in semiarid environments, due largely to the sparse vegetation cover. Nevertheless, these techniques show promise for providing more accurate information than is presently available for many BLM-administered lands.

  19. Measurement system with high accuracy for laser beam quality.

    PubMed

    Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

    2015-05-20

    Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M2 factor is less than 0.6%.

  20. Assessment of the Accuracy of Close Distance Photogrammetric JRC Data

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hyun; Poropat, George; Gratchev, Ivan; Balasubramaniam, Arumugam

    2016-11-01

    By using close range photogrammetry, this article investigates the accuracy of the photogrammetric estimation of rock joint roughness coefficients (JRC), a measure of the degree of roughness of rock joint surfaces. This methodology has proven to be convenient both in laboratory and in site conditions. However, the accuracy and precision of roughness profiles obtained from photogrammetric 3D images have not been properly established due to the variances caused by factors such as measurement errors and systematic errors in photogrammetry. In this study, the influences of camera-to-object distance, focal length and profile orientation on the accuracy of JRC values are investigated using several photogrammetry field surveys. Directional photogrammetric JRC data are compared with data derived from the measured profiles, so as to determine their accuracy. The extent of the accuracy of JRC values was examined based on the error models which were previously developed from laboratory tests and revised for better estimation in this study. The results show that high-resolution 3D images (point interval ≤1 mm) can reduce the JRC errors obtained from field photogrammetric surveys. Using the high-resolution images, the photogrammetric JRC values in the range of high oblique camera angles are highly consistent with the revised error models. Therefore, the analysis indicates that the revised error models facilitate the verification of the accuracy of photogrammetric JRC values.

  1. Towards Arbitrary Accuracy Inviscid Surface Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Hixon, Ray

    2002-01-01

    Inviscid nonlinear surface boundary conditions are currently limited to third order accuracy in time for non-moving surfaces and actually reduce to first order in time when the surfaces move. For steady-state calculations it may be possible to achieve higher accuracy in space, but high accuracy in time is required for efficient simulation of multiscale unsteady phenomena. A surprisingly simple technique is shown here that can be used to correct the normal pressure derivatives of the flow at a surface on a Cartesian grid so that arbitrarily high order time accuracy is achieved in idealized cases. This work demonstrates that nonlinear high order time accuracy at a solid surface is possible and desirable, but it also shows that the current practice of only correcting the pressure is inadequate.

  2. High accuracy OMEGA timekeeping

    NASA Technical Reports Server (NTRS)

    Imbier, E. A.

    1982-01-01

    The Smithsonian Astrophysical Observatory (SAO) operates a worldwide satellite tracking network which uses a combination of OMEGA as a frequency reference, dual timing channels, and portable clock comparisons to maintain accurate epoch time. Propagational charts from the U.S. Coast Guard OMEGA monitor program minimize diurnal and seasonal effects. Daily phase value publications of the U.S. Naval Observatory provide corrections to the field collected timing data to produce an averaged time line comprised of straight line segments called a time history file (station clock minus UTC). Depending upon clock location, reduced time data accuracies of between two and eight microseconds are typical.

  3. Stretched View Showing 'Victoria'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Stretched View Showing 'Victoria'

    This pair of images from the panoramic camera on NASA's Mars Exploration Rover Opportunity served as initial confirmation that the two-year-old rover is within sight of 'Victoria Crater,' which it has been approaching for more than a year. Engineers on the rover team were unsure whether Opportunity would make it as far as Victoria, but scientists hoped for the chance to study such a large crater with their roving geologist. Victoria Crater is 800 meters (nearly half a mile) in diameter, about six times wider than 'Endurance Crater,' where Opportunity spent several months in 2004 examining rock layers affected by ancient water.

    When scientists using orbital data calculated that they should be able to detect Victoria's rim in rover images, they scrutinized frames taken in the direction of the crater by the panoramic camera. To positively characterize the subtle horizon profile of the crater and some of the features leading up to it, researchers created a vertically-stretched image (top) from a mosaic of regular frames from the panoramic camera (bottom), taken on Opportunity's 804th Martian day (April 29, 2006).

    The stretched image makes mild nearby dunes look like more threatening peaks, but that is only a result of the exaggerated vertical dimension. This vertical stretch technique was first applied to Viking Lander 2 panoramas by Philip Stooke, of the University of Western Ontario, Canada, to help locate the lander with respect to orbiter images. Vertically stretching the image allows features to be more readily identified by the Mars Exploration Rover science team.

    The bright white dot near the horizon to the right of center (barely visible without labeling or zoom-in) is thought to be a light-toned outcrop on the far wall of the crater, suggesting that the rover can see over the low rim of Victoria. In figure 1, the northeast and southeast rims are labeled

  4. Municipal water consumption forecast accuracy

    NASA Astrophysics Data System (ADS)

    Fullerton, Thomas M.; Molina, Angel L.

    2010-06-01

    Municipal water consumption planning is an active area of research because of infrastructure construction and maintenance costs, supply constraints, and water quality assurance. In spite of that, relatively few water forecast accuracy assessments have been completed to date, although some internal documentation may exist as part of the proprietary "grey literature." This study utilizes a data set of previously published municipal consumption forecasts to partially fill that gap in the empirical water economics literature. Previously published municipal water econometric forecasts for three public utilities are examined for predictive accuracy against two random walk benchmarks commonly used in regional analyses. Descriptive metrics used to quantify forecast accuracy include root-mean-square error and Theil inequality statistics. Formal statistical assessments are completed using four-pronged error differential regression F tests. Similar to studies for other metropolitan econometric forecasts in areas with similar demographic and labor market characteristics, model predictive performances for the municipal water aggregates in this effort are mixed for each of the municipalities included in the sample. Given the competitiveness of the benchmarks, analysts should employ care when utilizing econometric forecasts of municipal water consumption for planning purposes, comparing them to recent historical observations and trends to insure reliability. Comparative results using data from other markets, including regions facing differing labor and demographic conditions, would also be helpful.

  5. Diagnostic Accuracy of Early Radiology in Acute Gastrointestinal Haemorrhage

    PubMed Central

    Allan, R. N.; Dykes, P. W.; Toye, D. K. M.

    1972-01-01

    The accuracy of early radiology in patients with acute gastrointestinal haemorrhage has been studied by a comparison of the radiological opinion with the established diagnosis. A full examination has proved safe and uncomplicated with a high degree of accuracy and no false-positive results. Analysis of the errors shows that the presence of residue discourages the radiologist from making the correct diagnosis, and modification of the standard bariummeal technique may be needed to overcome this difficulty. ImagesFIG. 2FIG. 3FIG. 4FIG. 5FIG. 6 PMID:4538882

  6. Evidence for Enhanced Interoceptive Accuracy in Professional Musicians

    PubMed Central

    Schirmer-Mokwa, Katharina L.; Fard, Pouyan R.; Zamorano, Anna M.; Finkel, Sebastian; Birbaumer, Niels; Kleber, Boris A.

    2015-01-01

    Interoception is defined as the perceptual activity involved in the processing of internal bodily signals. While the ability of internal perception is considered a relatively stable trait, recent data suggest that learning to integrate multisensory information can modulate it. Making music is a uniquely rich multisensory experience that has shown to alter motor, sensory, and multimodal representations in the brain of musicians. We hypothesize that musical training also heightens interoceptive accuracy comparable to other perceptual modalities. Thirteen professional singers, twelve string players, and thirteen matched non-musicians were examined using a well-established heartbeat discrimination paradigm complemented by self-reported dispositional traits. Results revealed that both groups of musicians displayed higher interoceptive accuracy than non-musicians, whereas no differences were found between singers and string-players. Regression analyses showed that accumulated musical practice explained about 49% variation in heartbeat perception accuracy in singers but not in string-players. Psychometric data yielded a number of psychologically plausible inter-correlations in musicians related to performance anxiety. However, dispositional traits were not a confounding factor on heartbeat discrimination accuracy. Together, these data provide first evidence indicating that professional musicians show enhanced interoceptive accuracy compared to non-musicians. We argue that musical training largely accounted for this effect. PMID:26733836

  7. Showing What They Know

    ERIC Educational Resources Information Center

    Cech, Scott J.

    2008-01-01

    Having students show their skills in three dimensions, known as performance-based assessment, dates back at least to Socrates. Individual schools such as Barrington High School--located just outside of Providence--have been requiring students to actively demonstrate their knowledge for years. The Rhode Island's high school graduating class became…

  8. The Ozone Show.

    ERIC Educational Resources Information Center

    Mathieu, Aaron

    2000-01-01

    Uses a talk show activity for a final assessment tool for students to debate about the ozone hole. Students are assessed on five areas: (1) cooperative learning; (2) the written component; (3) content; (4) self-evaluation; and (5) peer evaluation. (SAH)

  9. What Do Maps Show?

    ERIC Educational Resources Information Center

    Geological Survey (Dept. of Interior), Reston, VA.

    This curriculum packet, appropriate for grades 4-8, features a teaching poster which shows different types of maps (different views of Salt Lake City, Utah), as well as three reproducible maps and reproducible activity sheets which complement the maps. The poster provides teacher background, including step-by-step lesson plans for four geography…

  10. Show Me the Way

    ERIC Educational Resources Information Center

    Dicks, Matthew J.

    2005-01-01

    Because today's students have grown up steeped in video games and the Internet, most of them expect feedback, and usually gratification, very soon after they expend effort on a task. Teachers can get quick feedback to students by showing them videotapes of their learning performances. The author, a 3rd grade teacher describes how the seemingly…

  11. Chemistry Game Shows

    NASA Astrophysics Data System (ADS)

    Campbell, Susan; Muzyka, Jennifer

    2002-04-01

    We present a technological improvement to the use of game shows to help students review for tests. Our approach uses HTML files interpreted with a browser on a computer attached to an LCD projector. The HTML files can be easily modified for use of the game in a variety of courses.

  12. Honored Teacher Shows Commitment.

    ERIC Educational Resources Information Center

    Ratte, Kathy

    1987-01-01

    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  13. Talk Show Science.

    ERIC Educational Resources Information Center

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  14. Stage a Water Show

    ERIC Educational Resources Information Center

    Frasier, Debra

    2008-01-01

    In the author's book titled "The Incredible Water Show," the characters from "Miss Alaineus: A Vocabulary Disaster" used an ocean of information to stage an inventive performance about the water cycle. In this article, the author relates how she turned the story into hands-on science teaching for real-life fifth-grade students. The author also…

  15. Accuracy Analysis of a Box-wing Theoretical SRP Model

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoya; Hu, Xiaogong; Zhao, Qunhe; Guo, Rui

    2016-07-01

    For Beidou satellite navigation system (BDS) a high accuracy SRP model is necessary for high precise applications especially with Global BDS establishment in future. The BDS accuracy for broadcast ephemeris need be improved. So, a box-wing theoretical SRP model with fine structure and adding conical shadow factor of earth and moon were established. We verified this SRP model by the GPS Block IIF satellites. The calculation was done with the data of PRN 1, 24, 25, 27 satellites. The results show that the physical SRP model for POD and forecast for GPS IIF satellite has higher accuracy with respect to Bern empirical model. The 3D-RMS of orbit is about 20 centimeters. The POD accuracy for both models is similar but the prediction accuracy with the physical SRP model is more than doubled. We tested 1-day 3-day and 7-day orbit prediction. The longer is the prediction arc length, the more significant is the improvement. The orbit prediction accuracy with the physical SRP model for 1-day, 3-day and 7-day arc length are 0.4m, 2.0m, 10.0m respectively. But they are 0.9m, 5.5m and 30m with Bern empirical model respectively. We apply this means to the BDS and give out a SRP model for Beidou satellites. Then we test and verify the model with Beidou data of one month only for test. Initial results show the model is good but needs more data for verification and improvement. The orbit residual RMS is similar to that with our empirical force model which only estimate the force for along track, across track direction and y-bias. But the orbit overlap and SLR observation evaluation show some improvement. The remaining empirical force is reduced significantly for present Beidou constellation.

  16. Radiocarbon dating accuracy improved

    NASA Astrophysics Data System (ADS)

    Scientists have extended the accuracy of carbon-14 (14C) dating by correlating dates older than 8,000 years with uranium-thorium dates that span from 8,000 to 30,000 years before present (ybp, present = 1950). Edouard Bard, Bruno Hamelin, Richard Fairbanks and Alan Zindler, working at Columbia University's Lamont-Doherty Geological Observatory, dated corals from reefs off Barbados using both 14C and uranium-234/thorium-230 by thermal ionization mass spectrometry techniques. They found that the two age data sets deviated in a regular way, allowing the scientists to correlate the two sets of ages. The 14C dates were consistently younger than those determined by uranium-thorium, and the discrepancy increased to about 3,500 years at 20,000 ybp.

  17. EOS mapping accuracy study

    NASA Technical Reports Server (NTRS)

    Forrest, R. B.; Eppes, T. A.; Ouellette, R. J.

    1973-01-01

    Studies were performed to evaluate various image positioning methods for possible use in the earth observatory satellite (EOS) program and other earth resource imaging satellite programs. The primary goal is the generation of geometrically corrected and registered images, positioned with respect to the earth's surface. The EOS sensors which were considered were the thematic mapper, the return beam vidicon camera, and the high resolution pointable imager. The image positioning methods evaluated consisted of various combinations of satellite data and ground control points. It was concluded that EOS attitude control system design must be considered as a part of the image positioning problem for EOS, along with image sensor design and ground image processing system design. Study results show that, with suitable efficiency for ground control point selection and matching activities during data processing, extensive reliance should be placed on use of ground control points for positioning the images obtained from EOS and similar programs.

  18. Not a "reality" show.

    PubMed

    Wrong, Terence; Baumgart, Erica

    2013-01-01

    The authors of the preceding articles raise legitimate questions about patient and staff rights and the unintended consequences of allowing ABC News to film inside teaching hospitals. We explain why we regard their fears as baseless and not supported by what we heard from individuals portrayed in the filming, our decade-long experience making medical documentaries, and the full un-aired context of the scenes shown in the broadcast. The authors don't and can't know what conversations we had, what documents we reviewed, and what protections we put in place in each televised scene. Finally, we hope to correct several misleading examples cited by the authors as well as their offhand mischaracterization of our program as a "reality" show.

  19. Anatomy-aware measurement of segmentation accuracy

    NASA Astrophysics Data System (ADS)

    Tizhoosh, H. R.; Othman, A. A.

    2016-03-01

    Quantifying the accuracy of segmentation and manual delineation of organs, tissue types and tumors in medical images is a necessary measurement that suffers from multiple problems. One major shortcoming of all accuracy measures is that they neglect the anatomical significance or relevance of different zones within a given segment. Hence, existing accuracy metrics measure the overlap of a given segment with a ground-truth without any anatomical discrimination inside the segment. For instance, if we understand the rectal wall or urethral sphincter as anatomical zones, then current accuracy measures ignore their significance when they are applied to assess the quality of the prostate gland segments. In this paper, we propose an anatomy-aware measurement scheme for segmentation accuracy of medical images. The idea is to create a "master gold" based on a consensus shape containing not just the outline of the segment but also the outlines of the internal zones if existent or relevant. To apply this new approach to accuracy measurement, we introduce the anatomy-aware extensions of both Dice coefficient and Jaccard index and investigate their effect using 500 synthetic prostate ultrasound images with 20 different segments for each image. We show that through anatomy-sensitive calculation of segmentation accuracy, namely by considering relevant anatomical zones, not only the measurement of individual users can change but also the ranking of users' segmentation skills may require reordering.

  20. Accuracy evaluation of 3D lidar data from small UAV

    NASA Astrophysics Data System (ADS)

    Tulldahl, H. M.; Bissmarck, Fredrik; Larsson, Hâkan; Grönwall, Christina; Tolt, Gustav

    2015-10-01

    A UAV (Unmanned Aerial Vehicle) with an integrated lidar can be an efficient system for collection of high-resolution and accurate three-dimensional (3D) data. In this paper we evaluate the accuracy of a system consisting of a lidar sensor on a small UAV. High geometric accuracy in the produced point cloud is a fundamental qualification for detection and recognition of objects in a single-flight dataset as well as for change detection using two or several data collections over the same scene. Our work presented here has two purposes: first to relate the point cloud accuracy to data processing parameters and second, to examine the influence on accuracy from the UAV platform parameters. In our work, the accuracy is numerically quantified as local surface smoothness on planar surfaces, and as distance and relative height accuracy using data from a terrestrial laser scanner as reference. The UAV lidar system used is the Velodyne HDL-32E lidar on a multirotor UAV with a total weight of 7 kg. For processing of data into a geographically referenced point cloud, positioning and orientation of the lidar sensor is based on inertial navigation system (INS) data combined with lidar data. The combination of INS and lidar data is achieved in a dynamic calibration process that minimizes the navigation errors in six degrees of freedom, namely the errors of the absolute position (x, y, z) and the orientation (pitch, roll, yaw) measured by GPS/INS. Our results show that low-cost and light-weight MEMS based (microelectromechanical systems) INS equipment with a dynamic calibration process can obtain significantly improved accuracy compared to processing based solely on INS data.

  1. Groves model accuracy study

    NASA Astrophysics Data System (ADS)

    Peterson, Matthew C.

    1991-08-01

    The United States Air Force Environmental Technical Applications Center (USAFETAC) was tasked to review the scientific literature for studies of the Groves Neutral Density Climatology Model and compare the Groves Model with others in the 30-60 km range. The tasking included a request to investigate the merits of comparing accuracy of the Groves Model to rocketsonde data. USAFETAC analysts found the Groves Model to be state of the art for middle-atmospheric climatological models. In reviewing previous comparisons with other models and with space shuttle-derived atmospheric densities, good density vs altitude agreement was found in almost all cases. A simple technique involving comparison of the model with range reference atmospheres was found to be the most economical way to compare the Groves Model with rocketsonde data; an example of this type is provided. The Groves 85 Model is used routinely in USAFETAC's Improved Point Analysis Model (IPAM). To create this model, Dr. Gerald Vann Groves produced tabulations of atmospheric density based on data derived from satellite observations and modified by rocketsonde observations. Neutral Density as presented here refers to the monthly mean density in 10-degree latitude bands as a function of altitude. The Groves 85 Model zonal mean density tabulations are given in their entirety.

  2. Knowledge discovery by accuracy maximization

    PubMed Central

    Cacciatore, Stefano; Luchinat, Claudio; Tenori, Leonardo

    2014-01-01

    Here we describe KODAMA (knowledge discovery by accuracy maximization), an unsupervised and semisupervised learning algorithm that performs feature extraction from noisy and high-dimensional data. Unlike other data mining methods, the peculiarity of KODAMA is that it is driven by an integrated procedure of cross-validation of the results. The discovery of a local manifold’s topology is led by a classifier through a Monte Carlo procedure of maximization of cross-validated predictive accuracy. Briefly, our approach differs from previous methods in that it has an integrated procedure of validation of the results. In this way, the method ensures the highest robustness of the obtained solution. This robustness is demonstrated on experimental datasets of gene expression and metabolomics, where KODAMA compares favorably with other existing feature extraction methods. KODAMA is then applied to an astronomical dataset, revealing unexpected features. Interesting and not easily predictable features are also found in the analysis of the State of the Union speeches by American presidents: KODAMA reveals an abrupt linguistic transition sharply separating all post-Reagan from all pre-Reagan speeches. The transition occurs during Reagan’s presidency and not from its beginning. PMID:24706821

  3. Investigation of the Accuracy of Google Earth Elevation Data

    NASA Astrophysics Data System (ADS)

    El-Ashmawy, Khalid L. A.

    2016-09-01

    Digital Elevation Models (DEMs) comprise valuable source of elevation data required for many engineering applications. Contour lines, slope - aspect maps are part of their many uses. Moreover, DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally-produced relief maps. This paper proposes a method of generating DEM by using Google Earth elevation data which is easier and free. The case study consisted of three different small regions in the northern beach in Egypt. The accuracy of the Google earth derived elevation data are reported using root mean square error (RMSE), mean error (ME) and maximum absolute error (MAE). All these accuracy statistics were computed using the ground coordinates of 200 reference points for each region of the case study. The reference data was collected with total station survey. The results showed that the accuracies for the prepared DEMs are suitable for some certain engineering applications but inadequate to meet the standard required for fine/small scale DEM for very precise engineering study. The obtained accuracies for terrain with small height difference can be used for preparing large area cadastral, city planning, or land classification maps. In general, Google Earth elevation data can be used only for investigation and preliminary studies with low cost. It is strongly concluded that the users of Google Earth have to test the accuracy of elevation data by comparing with reference data before using it.

  4. Dust trajectory sensor: accuracy and data analysis.

    PubMed

    Xie, J; Sternovsky, Z; Grün, E; Auer, S; Duncan, N; Drake, K; Le, H; Horanyi, M; Srama, R

    2011-10-01

    The Dust Trajectory Sensor (DTS) instrument is developed for the measurement of the velocity vector of cosmic dust particles. The trajectory information is imperative in determining the particles' origin and distinguishing dust particles from different sources. The velocity vector also reveals information on the history of interaction between the charged dust particle and the magnetospheric or interplanetary space environment. The DTS operational principle is based on measuring the induced charge from the dust on an array of wire electrodes. In recent work, the DTS geometry has been optimized [S. Auer, E. Grün, S. Kempf, R. Srama, A. Srowig, Z. Sternovsky, and V Tschernjawski, Rev. Sci. Instrum. 79, 084501 (2008)] and a method of triggering was developed [S. Auer, G. Lawrence, E. Grün, H. Henkel, S. Kempf, R. Srama, and Z. Sternovsky, Nucl. Instrum. Methods Phys. Res. A 622, 74 (2010)]. This article presents the method of analyzing the DTS data and results from a parametric study on the accuracy of the measurements. A laboratory version of the DTS has been constructed and tested with particles in the velocity range of 2-5 km/s using the Heidelberg dust accelerator facility. Both the numerical study and the analyzed experimental data show that the accuracy of the DTS instrument is better than about 1% in velocity and 1° in direction.

  5. Dust trajectory sensor: Accuracy and data analysis

    SciTech Connect

    Xie, J.; Horanyi, M.; Sternovsky, Z.; Gruen, E.; Duncan, N.; Drake, K.; Le, H.; Auer, S.; Srama, R.

    2011-10-15

    The Dust Trajectory Sensor (DTS) instrument is developed for the measurement of the velocity vector of cosmic dust particles. The trajectory information is imperative in determining the particles' origin and distinguishing dust particles from different sources. The velocity vector also reveals information on the history of interaction between the charged dust particle and the magnetospheric or interplanetary space environment. The DTS operational principle is based on measuring the induced charge from the dust on an array of wire electrodes. In recent work, the DTS geometry has been optimized [S. Auer, E. Gruen, S. Kempf, R. Srama, A. Srowig, Z. Sternovsky, and V Tschernjawski, Rev. Sci. Instrum. 79, 084501 (2008)] and a method of triggering was developed [S. Auer, G. Lawrence, E. Gruen, H. Henkel, S. Kempf, R. Srama, and Z. Sternovsky, Nucl. Instrum. Methods Phys. Res. A 622, 74 (2010)]. This article presents the method of analyzing the DTS data and results from a parametric study on the accuracy of the measurements. A laboratory version of the DTS has been constructed and tested with particles in the velocity range of 2-5 km/s using the Heidelberg dust accelerator facility. Both the numerical study and the analyzed experimental data show that the accuracy of the DTS instrument is better than about 1% in velocity and 1 deg. in direction.

  6. Orbit Determination Accuracy for Comets on Earth-Impacting Trajectories

    NASA Technical Reports Server (NTRS)

    Kay-Bunnell, Linda

    2004-01-01

    The results presented show the level of orbit determination accuracy obtainable for long-period comets discovered approximately one year before collision with Earth. Preliminary orbits are determined from simulated observations using Gauss' method. Additional measurements are incorporated to improve the solution through the use of a Kalman filter, and include non-gravitational perturbations due to outgassing. Comparisons between observatories in several different circular heliocentric orbits show that observatories in orbits with radii less than 1 AU result in increased orbit determination accuracy for short tracking durations due to increased parallax per unit time. However, an observatory at 1 AU will perform similarly if the tracking duration is increased, and accuracy is significantly improved if additional observatories are positioned at the Sun-Earth Lagrange points L3, L4, or L5. A single observatory at 1 AU capable of both optical and range measurements yields the highest orbit determination accuracy in the shortest amount of time when compared to other systems of observatories.

  7. On Accuracy of Adaptive Grid Methods for Captured Shocks

    NASA Technical Reports Server (NTRS)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2002-01-01

    The accuracy of two grid adaptation strategies, grid redistribution and local grid refinement, is examined by solving the 2-D Euler equations for the supersonic steady flow around a cylinder. Second- and fourth-order linear finite difference shock-capturing schemes, based on the Lax-Friedrichs flux splitting, are used to discretize the governing equations. The grid refinement study shows that for the second-order scheme, neither grid adaptation strategy improves the numerical solution accuracy compared to that calculated on a uniform grid with the same number of grid points. For the fourth-order scheme, the dominant first-order error component is reduced by the grid adaptation, while the design-order error component drastically increases because of the grid nonuniformity. As a result, both grid adaptation techniques improve the numerical solution accuracy only on the coarsest mesh or on very fine grids that are seldom found in practical applications because of the computational cost involved. Similar error behavior has been obtained for the pressure integral across the shock. A simple analysis shows that both grid adaptation strategies are not without penalties in the numerical solution accuracy. Based on these results, a new grid adaptation criterion for captured shocks is proposed.

  8. 2-Year follow-up to STeP trial shows sustainability of structured self-monitoring of blood glucose utilization: results from the STeP practice logistics and usability survey (STeP PLUS).

    PubMed

    Friedman, Kevin; Noyes, Jeannette; Parkin, Christopher G

    2013-04-01

    We report findings from a follow-up survey of clinicians from the STeP study that assessed their attitudes toward and current use of the Accu-Chek(®) 360° View tool (Roche Diagnostics, Indianapolis, IN) approximately 2 years after the study was completed. The Accu-Chek 360° View tool enables patients to record/plot a seven-point self-monitoring of blood glucose (SMBG) profile (fasting, preprandial/2-h postprandial at each of the three meals, and bedtime) on 3 consecutive days, document meal sizes and energy levels, and comment on their SMBG experiences. Our findings showed that the majority of these physicians continue to use the tool with their patients, citing enhanced patient understanding and engagement, better discussions with patients regarding the impact of lifestyle behaviors, improved clinical outcomes, and better practice efficiencies as significant benefits of the tool.

  9. Accuracy and Precision of an IGRT Solution

    SciTech Connect

    Webster, Gareth J. Rowbottom, Carl G.; Mackay, Ranald I.

    2009-07-01

    Image-guided radiotherapy (IGRT) can potentially improve the accuracy of delivery of radiotherapy treatments by providing high-quality images of patient anatomy in the treatment position that can be incorporated into the treatment setup. The achievable accuracy and precision of delivery of highly complex head-and-neck intensity modulated radiotherapy (IMRT) plans with an IGRT technique using an Elekta Synergy linear accelerator and the Pinnacle Treatment Planning System (TPS) was investigated. Four head-and-neck IMRT plans were delivered to a semi-anthropomorphic head-and-neck phantom and the dose distribution was measured simultaneously by up to 20 microMOSFET (metal oxide semiconductor field-effect transmitter) detectors. A volumetric kilovoltage (kV) x-ray image was then acquired in the treatment position, fused with the phantom scan within the TPS using Syntegra software, and used to recalculate the dose with the precise delivery isocenter at the actual position of each detector within the phantom. Three repeat measurements were made over a period of 2 months to reduce the effect of random errors in measurement or delivery. To ensure that the noise remained below 1.5% (1 SD), minimum doses of 85 cGy were delivered to each detector. The average measured dose was systematically 1.4% lower than predicted and was consistent between repeats. Over the 4 delivered plans, 10/76 measurements showed a systematic error > 3% (3/76 > 5%), for which several potential sources of error were investigated. The error was ultimately attributable to measurements made in beam penumbrae, where submillimeter positional errors result in large discrepancies in dose. The implementation of an image-guided technique improves the accuracy of dose verification, particularly within high-dose gradients. The achievable accuracy of complex IMRT dose delivery incorporating image-guidance is within {+-} 3% in dose over the range of sample points. For some points in high-dose gradients

  10. In favour of the definition "adolescents with idiopathic scoliosis": juvenile and adolescent idiopathic scoliosis braced after ten years of age, do not show different end results. SOSORT award winner 2014

    PubMed Central

    2014-01-01

    Background The most important factor discriminating juvenile (JIS) from adolescent idiopathic scoliosis (AIS) is the risk of deformity progression. Brace treatment can change natural history, even when risk of progression is high. The aim of this study was to compare the end of growth results of JIS subjects, treated after 10 years of age, with final results of AIS. Methods Design: prospective observational controlled cohort study nested in a prospective database. Setting: outpatient tertiary referral clinic specialized in conservative treatment of spinal deformities. Inclusion criteria: idiopathic scoliosis; European Risser 0–2; 25 degrees to 45 degrees Cobb; start treatment age: 10 years or more, never treated before. Exclusion criteria: secondary scoliosis, neurological etiology, prior treatment for scoliosis (brace or surgery). Groups: 27 patients met the inclusion criteria for the AJIS, (Juvenile Idiopathic Scoliosis treated in adolescence), demonstrated by an x-ray before 10 year of age, and treatment start after 10 years of age. AIS group included 45 adolescents with a diagnostic x-ray made after the threshold of age 10 years. Results at the end of growth were analysed; the threshold of 5 Cobb degree to define worsened, improved and stabilized curves was considered. Statistics: Mean and SD were used for descriptive statistics of clinical and radiographic changes. Relative Risk of failure (RR), Chi-square and T-test of all data was calculated to find differences among the two groups. 95% Confidence Interval (CI) , and of radiographic changes have been calculated. Results We did not find any Cobb angle significant differences among groups at baseline and at the end of treatment. The only difference was in the number of patients progressed above 45 degrees, found in the JIS group. The RR of progression of AJIS was, 1.35 (IC95% 0.57-3.17) versus AIS, and it wasn't statistically significant in the AJIS group, in respect to AIS group (p = 0.5338). Conclusion

  11. An automated method for the evaluation of the pointing accuracy of sun-tracking devices

    NASA Astrophysics Data System (ADS)

    Baumgartner, Dietmar J.; Rieder, Harald E.; Pötzi, Werner; Freislich, Heinrich; Strutzmann, Heinz

    2016-04-01

    The accuracy of measurements of solar radiation (direct and diffuse radiation) depends significantly on the accuracy of the operational sun-tracking device. Thus rigid targets for instrument performance and operation are specified for international monitoring networks, such as e.g., the Baseline Surface Radiation Network (BSRN) operating under the auspices of the World Climate Research Program (WCRP). Sun-tracking devices fulfilling these accuracy targets are available from various instrument manufacturers, however none of the commercially available systems comprises a secondary accuracy control system, allowing platform operators to independently validate the pointing accuracy of sun-tracking sensors during operation. Here we present KSO-STREAMS (KSO-SunTRackEr Accuracy Monitoring System), a fully automated, system independent and cost-effective method for evaluating the pointing accuracy of sun-tracking devices. We detail the monitoring system setup, its design and specifications and results from its application to the sun-tracking system operated at the Austrian RADiation network (ARAD) site Kanzelhöhe Observatory (KSO). Results from KSO-STREAMS (for mid-March to mid-June 2015) show that the tracking accuracy of the device operated at KSO lies well within BSRN specifications (i.e. 0.1 degree accuracy). We contrast results during clear-sky and partly cloudy conditions documenting sun-tracking performance at manufacturer specified accuracies for active tracking (0.02 degrees) and highlight accuracies achieved during passive tracking i.e. periods with less than 300 W m-2 direct radiation. Furthermore we detail limitations to tracking surveillance during overcast conditions and periods of partial solar limb coverage by clouds.

  12. Clinical consequences of the Calypso trial showing superiority of PEG-liposomal doxorubicin and carboplatin over paclitaxel and carboplatin in recurrent ovarian cancer: results of an Austrian gynecologic oncologists' expert meeting.

    PubMed

    Petru, Edgar; Reinthaller, Alexander; Angleitner-Boubenizek, Lukas; Schauer, Christian; Zeimet, Alain; Dirschlmayer, Wolfgang; Medl, Michael; Stummvoll, Wolfgang; Sevelda, Paul; Marth, Christian

    2010-11-01

    The Calypso trial showed an improved progression-free survival with PEG-liposomal doxorubicin (PLD) and carboplatin (P) as compared with the standard regimen paclitaxel (PCLTX) and P in the second- or third-line treatment of platinum-sensitive epithelial ovarian cancer [1]. A panel of Austrian gynecologic oncologists discussed the clinical consequences of the data from the Calypso study for the routine practice. PLD + P had a significantly lower rate of alopecia and neuropathy than the taxane regimen, both toxicities which compromise the quality of life. Due to possible significant thrombocytopenia, the blood counts of patients undergoing PLD + P therapy should be monitored weekly. Patients receiving PLD/P are at higher risk of nausea and vomiting. Palmoplantar erythrodysesthesia (hand-foot syndrome) is a significant toxicity of PLD + P most prevalent after the third or fourth cycle. Prophylaxis consists of avoiding pressure on feet and hands and other parts of the body. Similarly, prophylaxis of mucositis seems important and includes avoiding consumption of hot, spicy and salty foods and drinks. Mouth dryness should be avoided. Premedication with antiemetics and dexamethasone dissolved in 5% glucose is done to prevent hypersensitivity to PLD. In conclusion, the therapeutic index is more favorable for PLD + P than for PCTX + P.

  13. Are regulatory strategies necessary in the regulation of accuracy? The effect of direct-access answers.

    PubMed

    Luna, Karlos; Martín-Luengo, Beatriz; Brewer, Neil

    2015-11-01

    Previous studies have shown that, when people asked to retrieve something from memory have the chance to regulate memory accuracy, the accuracy of their final report increases. Such regulation of accuracy can be made through one of several strategies: the report option, the grain-size option, or the plurality option. However, sometimes an answer can be directly accessed and reported without resorting to such strategies. The direct-access answers are expected to be fast, have high accuracy, and be rated with high probabilities of being correct. Thus, direct-access answers alone could explain the increase of accuracy that has been considered the outcome of regulatory strategies. If so, regulatory strategies may not be needed to explain the previous results. In two experiments, we disentangled the effects of direct-access answers and regulatory strategies in the increase of accuracy. We identified a subset of direct-access answers, and then examined the regulation of accuracy with the plurality option when they were removed. Participants answered questions with six (Exp. 1) or five (Exp. 2) alternatives. Their task was, first, to select as many alternatives as they wanted and, second, to select only two or four alternatives. The results showed that the direct-access answer affected the regulation of accuracy and made it easier. However, the results also showed that regulatory strategies, in this case the plurality option, are needed to explain why the accuracy of final report increases after successful regulation. This research highlighted the relevance of taking direct-access answers into account in the study of the regulation of accuracy.

  14. Numerical and analytic results showing the suppression of secondary electron emission from velvet and foam, and a geometric view factor model to guide the development of a surface to suppress SEE

    NASA Astrophysics Data System (ADS)

    Swanson, Charles; Kaganovich, I. D.

    2016-09-01

    The technique of suppressing secondary electron emission (SEE) from a surface by texturing it is developing rapidly in recent years. We have specific and general results in support of this technique: We have performed numerical and analytic calculations for determining the effective secondary electron yield (SEY) from velvet, which is an array of long cylinders on the micro-scale, and found velvet to be suitable for suppressing SEY from a normally incident primary distribution. We have performed numerical and analytic calculations also for metallic foams, which are an isotropic lattice of fibers on the micro-scale, and found foams to be suitable for suppressing SEY from an isotropic primary distribution. More generally, we have created a geometric weighted view factor model for determining the SEY suppression of a given surface geometry, which has optimization of SEY as a natural application. The optimal surface for suppressing SEY does not have finite area and has no smallest feature size, making it fractal in nature. This model gives simple criteria for a physical, non-fractal surface to suppress SEY. We found families of optimal surfaces to suppress SEY given a finite surface area. The research is supported by Air Force Office of Scientific Research (AFSOR).

  15. Data supporting the high-accuracy haplotype imputation using unphased genotype data as the references.

    PubMed

    Li, Wenzhi; Xu, Wei; He, Shaohua; Ma, Li; Song, Qing

    2016-09-01

    The data presented in this article is related to the research article entitled "High-accuracy haplotype imputation using unphased genotype data as the references" which reports the unphased genotype data can be used as reference for haplotyping imputation [1]. This article reports different implementation generation pipeline, the results of performance comparison between different implementations (A, B, and C) and between HiFi and three major imputation software tools. Our data showed that the performances of these three implementations are similar on accuracy, in which the accuracy of implementation-B is slightly but consistently higher than A and C. HiFi performed better on haplotype imputation accuracy and three other software performed slightly better on genotype imputation accuracy. These data may provide a strategy for choosing optimal phasing pipeline and software for different studies.

  16. Increasing Accuracy in Environmental Measurements

    NASA Astrophysics Data System (ADS)

    Jacksier, Tracey; Fernandes, Adelino; Matthew, Matt; Lehmann, Horst

    2016-04-01

    Human activity is increasing the concentrations of green house gases (GHG) in the atmosphere which results in temperature increases. High precision is a key requirement of atmospheric measurements to study the global carbon cycle and its effect on climate change. Natural air containing stable isotopes are used in GHG monitoring to calibrate analytical equipment. This presentation will examine the natural air and isotopic mixture preparation process, for both molecular and isotopic concentrations, for a range of components and delta values. The role of precisely characterized source material will be presented. Analysis of individual cylinders within multiple batches will be presented to demonstrate the ability to dynamically fill multiple cylinders containing identical compositions without isotopic fractionation. Additional emphasis will focus on the ability to adjust isotope ratios to more closely bracket sample types without the reliance on combusting naturally occurring materials, thereby improving analytical accuracy.

  17. Emotional and Social Factors influence Poker Decision Making Accuracy.

    PubMed

    Laakasuo, Michael; Palomäki, Jussi; Salmela, Mikko

    2015-09-01

    Poker is a social game, where success depends on both game strategic knowledge and emotion regulation abilities. Thus, poker provides a productive environment for studying the effects of emotional and social factors on micro-economic decision making. Previous research indicates that experiencing negative emotions, such as moral anger, reduces mathematical accuracy in poker decision making. Furthermore, various social aspects of the game—such as losing against "bad players" due to "bad luck"—seem to fuel these emotional states. We designed an Internet-based experiment, where participants' (N = 459) mathematical accuracy in five different poker decision making tasks were assessed. In addition, we manipulated the emotional and social conditions under which the tasks were presented, in a 2 × 2 experimental setup: (1) Anger versus neutral emotional state—participants were primed either with an anger-inducing, or emotionally neutral story, and (2) Social cue versus non-social cue—during the tasks, either an image of a pair of human eyes was "following" the mouse cursor, or an image of a black moving box was presented. The results showed that anger reduced mathematical accuracy of decision making only when participants were "being watched" by a pair of moving eyes. Experienced poker players made mathematically more accurate decisions than inexperienced ones. The results contribute to current understanding on how emotional and social factors influence decision making accuracy in economic games.

  18. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

    PubMed Central

    Fujii, Kenjiro; Arie, Hiroaki; Wang, Wei; Kaneko, Yuto; Sakamoto, Yoshihiro; Schmitz, Alexander; Sugano, Shigeki

    2016-01-01

    Indoor positioning remains an open problem, because it is difficult to achieve satisfactory accuracy within an indoor environment using current radio-based localization technology. In this study, we investigate the use of Indoor Messaging System (IMES) radio for high-accuracy indoor positioning. A hybrid positioning method combining IMES radio strength information and pedestrian dead reckoning information is proposed in order to improve IMES localization accuracy. For understanding the carrier noise ratio versus distance relation for IMES radio, the signal propagation of IMES radio is modeled and identified. Then, trilateration and extended Kalman filtering methods using the radio propagation model are developed for position estimation. These methods are evaluated through robot localization and pedestrian localization experiments. The experimental results show that the proposed hybrid positioning method achieved average estimation errors of 217 and 1846 mm in robot localization and pedestrian localization, respectively. In addition, in order to examine the reason for the positioning accuracy of pedestrian localization being much lower than that of robot localization, the influence of the human body on the radio propagation is experimentally evaluated. The result suggests that the influence of the human body can be modeled. PMID:26828492

  19. Test Expectancy Affects Metacomprehension Accuracy

    ERIC Educational Resources Information Center

    Thiede, Keith W.; Wiley, Jennifer; Griffin, Thomas D.

    2011-01-01

    Background: Theory suggests that the accuracy of metacognitive monitoring is affected by the cues used to judge learning. Researchers have improved monitoring accuracy by directing attention to more appropriate cues; however, this is the first study to more directly point students to more appropriate cues using instructions regarding tests and…

  20. Towards Experimental Accuracy from the First Principles

    NASA Astrophysics Data System (ADS)

    Polyansky, O. L.; Lodi, L.; Tennyson, J.; Zobov, N. F.

    2013-06-01

    Producing ab initio ro-vibrational energy levels of small, gas-phase molecules with an accuracy of 0.10 cm^{-1} would constitute a significant step forward in theoretical spectroscopy and would place calculated line positions considerably closer to typical experimental accuracy. Such an accuracy has been recently achieved for the H_3^+ molecular ion for line positions up to 17 000 cm ^{-1}. However, since H_3^+ is a two-electron system, the electronic structure methods used in this study are not applicable to larger molecules. A major breakthrough was reported in ref., where an accuracy of 0.10 cm^{-1} was achieved ab initio for seven water isotopologues. Calculated vibrational and rotational energy levels up to 15 000 cm^{-1} and J=25 resulted in a standard deviation of 0.08 cm^{-1} with respect to accurate reference data. As far as line intensities are concerned, we have already achieved for water a typical accuracy of 1% which supersedes average experimental accuracy. Our results are being actively extended along two major directions. First, there are clear indications that our results for water can be improved to an accuracy of the order of 0.01 cm^{-1} by further, detailed ab initio studies. Such level of accuracy would already be competitive with experimental results in some situations. A second, major, direction of study is the extension of such a 0.1 cm^{-1} accuracy to molecules containg more electrons or more than one non-hydrogen atom, or both. As examples of such developments we will present new results for CO, HCN and H_2S, as well as preliminary results for NH_3 and CH_4. O.L. Polyansky, A. Alijah, N.F. Zobov, I.I. Mizus, R. Ovsyannikov, J. Tennyson, L. Lodi, T. Szidarovszky and A.G. Csaszar, Phil. Trans. Royal Soc. London A, {370}, 5014-5027 (2012). O.L. Polyansky, R.I. Ovsyannikov, A.A. Kyuberis, L. Lodi, J. Tennyson and N.F. Zobov, J. Phys. Chem. A, (in press). L. Lodi, J. Tennyson and O.L. Polyansky, J. Chem. Phys. {135}, 034113 (2011).

  1. Accuracy assessment/validation methodology and results of 2010–11 land-cover/land-use data for Pools 13, 26, La Grange, and Open River South, Upper Mississippi River System

    USGS Publications Warehouse

    Jakusz, J.W.; Dieck, J.J.; Langrehr, H.A.; Ruhser, J.J.; Lubinski, S.J.

    2016-01-11

    Similar to an AA, validation involves generating random points based on the total area for each map class. However, instead of collecting field data, two or three individuals not involved with the photo-interpretative mapping separately review each of the points onscreen and record a best-fit vegetation type(s) for each site. Once the individual analyses are complete, results are joined together and a comparative analysis is performed. The objective of this initial analysis is to identify areas where the validation results were in agreement (matches) and areas where validation results were in disagreement (mismatches). The two or three individuals then perform an analysis, looking at each mismatched site, and agree upon a final validation class. (If two vegetation types at a specific site appear to be equally prevalent, the validation team is permitted to assign the site two best-fit vegetation types.) Following the validation team’s comparative analysis of vegetation assignments, the data are entered into a database and compared to the mappers’ vegetation assignments. Agreements and disagreements between the map and validation classes are identified, and a contingency table is produced. This document presents the AA processes/results for Pools 13 and La Grange, as well as the validation process/results for Pools 13 and 26 and Open River South.

  2. High-accuracy user identification using EEG biometrics.

    PubMed

    Koike-Akino, Toshiaki; Mahajan, Ruhi; Marks, Tim K; Ye Wang; Watanabe, Shinji; Tuzel, Oncel; Orlik, Philip

    2016-08-01

    We analyze brain waves acquired through a consumer-grade EEG device to investigate its capabilities for user identification and authentication. First, we show the statistical significance of the P300 component in event-related potential (ERP) data from 14-channel EEGs across 25 subjects. We then apply a variety of machine learning techniques, comparing the user identification performance of various different combinations of a dimensionality reduction technique followed by a classification algorithm. Experimental results show that an identification accuracy of 72% can be achieved using only a single 800 ms ERP epoch. In addition, we demonstrate that the user identification accuracy can be significantly improved to more than 96.7% by joint classification of multiple epochs.

  3. Adult Metacomprehension: Judgment Processes and Accuracy Constraints

    ERIC Educational Resources Information Center

    Zhao, Qin; Linderholm, Tracy

    2008-01-01

    The objective of this paper is to review and synthesize two interrelated topics in the adult metacomprehension literature: the bases of metacomprehension judgment and the constraints on metacomprehension accuracy. Our review shows that adult readers base their metacomprehension judgments on different types of information, including experiences…

  4. Accuracy and Precision of Silicon Based Impression Media for Quantitative Areal Texture Analysis

    PubMed Central

    Goodall, Robert H.; Darras, Laurent P.; Purnell, Mark A.

    2015-01-01

    Areal surface texture analysis is becoming widespread across a diverse range of applications, from engineering to ecology. In many studies silicon based impression media are used to replicate surfaces, and the fidelity of replication defines the quality of data collected. However, while different investigators have used different impression media, the fidelity of surface replication has not been subjected to quantitative analysis based on areal texture data. Here we present the results of an analysis of the accuracy and precision with which different silicon based impression media of varying composition and viscosity replicate rough and smooth surfaces. Both accuracy and precision vary greatly between different media. High viscosity media tested show very low accuracy and precision, and most other compounds showed either the same pattern, or low accuracy and high precision, or low precision and high accuracy. Of the media tested, mid viscosity President Jet Regular Body and low viscosity President Jet Light Body (Coltène Whaledent) are the only compounds to show high levels of accuracy and precision on both surface types. Our results show that data acquired from different impression media are not comparable, supporting calls for greater standardisation of methods in areal texture analysis. PMID:25991505

  5. Accuracy and Precision of Silicon Based Impression Media for Quantitative Areal Texture Analysis

    NASA Astrophysics Data System (ADS)

    Goodall, Robert H.; Darras, Laurent P.; Purnell, Mark A.

    2015-05-01

    Areal surface texture analysis is becoming widespread across a diverse range of applications, from engineering to ecology. In many studies silicon based impression media are used to replicate surfaces, and the fidelity of replication defines the quality of data collected. However, while different investigators have used different impression media, the fidelity of surface replication has not been subjected to quantitative analysis based on areal texture data. Here we present the results of an analysis of the accuracy and precision with which different silicon based impression media of varying composition and viscosity replicate rough and smooth surfaces. Both accuracy and precision vary greatly between different media. High viscosity media tested show very low accuracy and precision, and most other compounds showed either the same pattern, or low accuracy and high precision, or low precision and high accuracy. Of the media tested, mid viscosity President Jet Regular Body and low viscosity President Jet Light Body (Coltène Whaledent) are the only compounds to show high levels of accuracy and precision on both surface types. Our results show that data acquired from different impression media are not comparable, supporting calls for greater standardisation of methods in areal texture analysis.

  6. Accuracy of the CONTOUR® Blood Glucose Monitoring System

    PubMed Central

    Harrison, Bern; Leazenby, Cheryl; Halldorsdottir, Solveig

    2011-01-01

    Objective The aim of the study was to assess the accuracy of the CONTOUR® blood glucose monitoring system (BGMS) according to the International Organization for Standardization's International Standard 15197 (ISO 15197:2003) guidelines and to more stringent criteria. Method Finger stick blood samples from 105 subjects with diabetes (25 with type 1, 77 with type 2, and 3 with type unknown) were tested using the CONTOUR BGMS and YSI glucose analyzer. Results 99.3% of results were within ISO 15197:2003 criteria (±15 mg/dl of YSI results at glucose concentrations <75 mg/dl and ±20% at glucose concentrations ≥75 mg/dl). Additionally, 96.7% of results were accurate according to more stringent criteria (±15 mg/dl of YSI results for glucose concentrations <100 mg/dl and ±15% for glucose concentrations ≥100 mg/dl). Error grid analysis showed that 99.3% and 0.7% of results were within zones A and B, respectively. Conclusion The CONTOUR BGMS exceeded both the minimum acceptable accuracy based on ISO 15197:2003 and the more stringent accuracy criteria. PMID:21880245

  7. Goce Gradients In Various Reference Frames and Their Accuracies

    NASA Astrophysics Data System (ADS)

    Müller, J.; Oberndorfer, H.

    The objective of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) is the determination of the Earth's gravity field with high spatial resolution. The main sensor is a gradiometer which measures gravity gradients, i.e. the matrix of the sec- ond derivatives of the gravitational potential. Some of them (the diagonal compo- nents of the gravity tensor) are observed with highest accuracy of about 3 mE/ (Hz), whereas the others are determined less accurate. The gradients will be observed in the instrument frame, which approximates the satellite frame (beside some misalign- ments). Some users, however, need the gradients in more convenient frames for further processing. For the transformation of the gradients in other frames (e.g.in the nominal orbital frame or a terrestrial frame), the transformation parameters (orientation angles) and the single components of the gravity tensor have to be known with sufficient ac- curacy. As the accuracy of both quantities is restricted because of conceptual reasons, the resulting gradients in the new frames have only a reduced accuracy. We show how the elements of the gravity tensor and their accuracies look like in the various frames as well as their spectral behaviour.

  8. Factors Influencing Science Content Accuracy in Elementary Inquiry Science Lessons

    NASA Astrophysics Data System (ADS)

    Nowicki, Barbara L.; Sullivan-Watts, Barbara; Shim, Minsuk K.; Young, Betty; Pockalny, Robert

    2013-06-01

    Elementary teachers face increasing demands to engage children in authentic science process and argument while simultaneously preparing them with knowledge of science facts, vocabulary, and concepts. This reform is particularly challenging due to concerns that elementary teachers lack adequate science background to teach science accurately. This study examined 81 in-classroom inquiry science lessons for preservice education majors and their cooperating teachers to determine the accuracy of the science content delivered in elementary classrooms. Our results showed that 74 % of experienced teachers and 50 % of student teachers presented science lessons with greater than 90 % accuracy. Eleven of the 81 lessons (9 preservice, 2 cooperating teachers) failed to deliver accurate science content to the class. Science content accuracy was highly correlated with the use of kit-based resources supported with professional development, a preference for teaching science, and grade level. There was no correlation between the accuracy of science content and some common measures of teacher content knowledge (i.e., number of college science courses, science grades, or scores on a general science content test). Our study concluded that when provided with high quality curricular materials and targeted professional development, elementary teachers learn needed science content and present it accurately to their students.

  9. Colored noise effects on batch attitude accuracy estimates

    NASA Technical Reports Server (NTRS)

    Bilanow, Stephen

    1991-01-01

    The effects of colored noise on the accuracy of batch least squares parameter estimates with applications to attitude determination cases are investigated. The standard approaches used for estimating the accuracy of a computed attitude commonly assume uncorrelated (white) measurement noise, while in actual flight experience measurement noise often contains significant time correlations and thus is colored. For example, horizon scanner measurements from low Earth orbit were observed to show correlations over many minutes in response to large scale atmospheric phenomena. A general approach to the analysis of the effects of colored noise is investigated, and interpretation of the resulting equations provides insight into the effects of any particular noise color and the worst case noise coloring for any particular parameter estimate. It is shown that for certain cases, the effects of relatively short term correlations can be accommodated by a simple correction factor. The errors in the predicted accuracy assuming white noise and the reduced accuracy due to the suboptimal nature of estimators that do not take into account the noise color characteristics are discussed. The appearance of a variety of sample noise color characteristics are demonstrated through simulation, and their effects are discussed for sample estimation cases. Based on the analysis, options for dealing with the effects of colored noise are discussed.

  10. Why do delayed summaries improve metacomprehension accuracy?

    PubMed

    Anderson, Mary C M; Thiede, Keith W

    2008-05-01

    We showed that metacomprehension accuracy improved when participants (N=87 college students) wrote summaries of texts prior to judging their comprehension; however, accuracy only improved when summaries were written after a delay, not when written immediately after reading. We evaluated two hypotheses proposed to account for this delayed-summarization effect (the accessibility hypothesis and the situation model hypothesis). The data suggest that participants based metacomprehension judgments more on the gist of texts when they generated summaries after a delay; whereas, they based judgments more on details when they generated summaries immediately after reading. Focusing on information relevant to the situation model of a text (the gist of a text) produced higher levels of metacomprehension accuracy, which is consistent with situation model hypothesis.

  11. Accuracy of multi-look geo-coding

    NASA Astrophysics Data System (ADS)

    Weidaw, E. M.; Roth, M. W.; Brown, M. Z.; Scheck, A. E.

    2010-04-01

    Very accurate geo-location (geo-coding) of imagery taken at long range is a very large challenge. Whereas GPS can supply a very accurate sensor position, the hardware for the required precision pointing can have a very large cost. Roth, et al (2005) showed that because of the accuracy of lidar range-data, a tri-lateration method (called Multi-Look Lidar or Multi-Look Geo-Coding) can achieve very accurate geocoding at very long ranges and very low cost by using data-driven processing. This paper presents extensive flight-testing results using commercial airborne lidar. Because the tri-lateration method produces a large number of control points, the resulting accuracy of the geo-coded lidar data is somewhat better than that predicted for a single control point due to control-point averaging.

  12. The effects of domain knowledge on metacomprehension accuracy.

    PubMed

    Griffin, Thomas D; Jee, Benjamin D; Wiley, Jennifer

    2009-10-01

    In the present research, we examined the relationship between readers' domain knowledge and their ability to judge their comprehension of novel domain-related material. Participants with varying degrees of baseball knowledge read five texts on baseball-related topics and five texts on non-baseball-related topics, predicted their performance, and completed tests for each text. Baseball knowledge was positively related to absolute accuracy within the baseball domain but was unrelated to relative accuracy within the baseball domain. Also, the readers showed a general underconfidence bias, but the bias was less extreme for higher knowledge readers. The results challenge common assumptions that experts' metacognitive judgments are less accurate than novices'. Results involving topic familiarity ratings and a no-reading control group suggest that higher knowledge readers are not more likely to ignore text-specific cues in favor of a domain familiarity heuristic, but they do appear to make more effective use of domain familiarity in predicting absolute performance levels.

  13. How do illusions constrain goal-directed movement: perceptual and visuomotor influences on speed/accuracy trade-off.

    PubMed

    Skewes, Joshua C; Roepstorff, Andreas; Frith, Christopher D

    2011-03-01

    Recent research shows that visual processing influences the speed/accuracy trade-off people use when performing goal-directed movement. This raises the question of how this influence is produced in visual cognition. Visual influences on speed/accuracy trade-off could be produced in conscious visual perception, in non-conscious visuomotor transformation, or by some interaction of conscious perceptual and non-conscious visuomotor processes. There is independent evidence showing that both perceptual and visuomotor processes are involved in trading off speed and accuracy; however, the interaction between these processes has yet to be investigated. We present an experiment in which we show that a change in visual consciousness induced by a perceptual illusion affects the speed and accuracy of goal-directed movements, suggesting that perceptual and visuomotor processes do interact in speed/accuracy trade-off. We discuss the consequences of these results for theories of visual function more generally.

  14. Accuracy of Measurements in Oblique Aerial Images for Urban Environment

    NASA Astrophysics Data System (ADS)

    Ostrowski, W.

    2016-10-01

    were referred to image orientation accuracy and to the ground sampling distance of the used images. The results show that the recent development of image orientation methods for oblique aerial images allow these images to be used for high quality photogrammetric measurements.

  15. Accuracy of GFR Estimation in Obese Patients

    PubMed Central

    Guebre-Egziabher, Fitsum; Sens, Florence; Nguyen-Tu, Marie-Sophie; Juillard, Laurent; Dubourg, Laurence; Hadj-Aissa, Aoumeur

    2014-01-01

    Background and objectives Adequate estimation of renal function in obese patients is essential for the classification of patients in CKD category as well as the dose adjustment of drugs. However, the body size descriptor for GFR indexation is still debatable, and formulas are not validated in patients with extreme variations of weight. Design, setting, participants, & measurements This study included 209 stages 1–5 CKD obese patients referred to the Department of Renal Function Study at the University Hospital in Lyon between 2010 and 2013 because of suspected renal dysfunction. GFR was estimated with the Chronic Kidney Disease and Epidemiology equation (CKD-EPI) and measured with a gold standard method (inulin or iohexol) not indexed (mGFR) or indexed to body surface area determined by the Dubois and Dubois formula with either real (mGFRr) or ideal (mGFRi) body weight. Mean bias (eGFR−mGFR), precision, and accuracy of mGFR were compared with the results obtained for nonobese participants (body mass index between 18.5 and 24.9) who had a GFR measurement during the same period of time. Results Mean mGFRr (51.6±24.2 ml/min per 1.73 m2) was significantly lower than mGFR, mGFRi, and eGFRCKD-EPI. eGFRCKD-EPI had less bias with mGFR (0.29; −1.7 to 2.3) and mGFRi (−1.62; −3.1 to 0.45) compared with mGFRr (8.7; 7 to 10). This result was confirmed with better accuracy for the whole cohort (78% for mGFR, 84% for mGFRi, and 72% for mGFRr) and participants with CKD stages 3–5. Moreover, the Bland Altman plot showed better agreement between mGFR and eGFRCKD-EPI. The bias between eGFRCKD-EPI and mGFRr was greater in obese than nonobese participants (8.7 versus 0.58, P<0.001). Conclusions This study shows that, in obese CKD patients, the performance of eGFRCKD-EPI is good for GFR≤60 ml/min per 1.73 m2. Indexation of mGFR with body surface area using ideal body weight gives less bias than mGFR scaled with body surface area using real body weight. PMID:24482068

  16. High Accuracy Time Transfer Synchronization

    DTIC Science & Technology

    1994-12-01

    HIGH ACCURACY TIME TRANSFER SYNCHRONIZATION Paul Wheeler, Paul Koppang, David Chalmers, Angela Davis, Anthony Kubik and William Powell U.S. Naval...Observatory Washington, DC 20392 Abstract In July 1994, the US Naval Observatory (USNO) Time Service System Engineering Division conducted a...field test to establish a baseline accuracy for two-way satellite time transfer synchro- nization. Three Hewlett-Packard model 5071 high performance

  17. Process Analysis Via Accuracy Control

    DTIC Science & Technology

    1982-02-01

    0 1 4 3 NDARDS THE NATIONAL February 1982 Process Analysis Via Accuracy Control RESEARCH PROG RAM U.S. DEPARTMENT OF TRANSPORTATION Maritime...SUBTITLE Process Analysis Via Accuracy Control 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...examples are contained in Appendix C. Included, are examples of how “A/C” process - analysis leads to design improvement and how a change in sequence can

  18. Accuracy assessment of the integration of GNSS and a MEMS IMU in a terrestrial platform.

    PubMed

    Madeira, Sergio; Yan, Wenlin; Bastos, Luísa; Gonçalves, José A

    2014-11-04

    MEMS Inertial Measurement Units are available at low cost and can replace expensive units in mobile mapping platforms which need direct georeferencing. This is done through the integration with GNSS measurements in order to achieve a continuous positioning solution and to obtain orientation angles. This paper presents the results of the assessment of the accuracy of a system that integrates GNSS and a MEMS IMU in a terrestrial platform. We describe the methodology used and the tests realized where the accuracy of the positions and orientation parameters were assessed using an independent photogrammetric technique employing cameras that integrate the mobile mapping system developed by the authors. Results for the accuracy of attitude angles and coordinates show that accuracies better than a decimeter in positions, and under a degree in angles, can be achieved even considering that the terrestrial platform is operating in less than favorable environments.

  19. Size-Dependent Accuracy of Nanoscale Thermometers.

    PubMed

    Alicki, Robert; Leitner, David M

    2015-07-23

    The accuracy of two classes of nanoscale thermometers is estimated in terms of size and system-dependent properties using the spin-boson model. We consider solid state thermometers, where the energy splitting is tuned by thermal properties of the material, and fluorescent organic thermometers, in which the fluorescence intensity depends on the thermal population of conformational states of the thermometer. The results of the theoretical model compare well with the accuracy reported for several nanothermometers that have been used to measure local temperature inside living cells.

  20. National Orange Show Photovoltaic Demonstration

    SciTech Connect

    Dan Jimenez Sheri Raborn, CPA; Tom Baker

    2008-03-31

    National Orange Show Photovoltaic Demonstration created a 400KW Photovoltaic self-generation plant at the National Orange Show Events Center (NOS). The NOS owns a 120-acre state fairground where it operates an events center and produces an annual citrus fair known as the Orange Show. The NOS governing board wanted to employ cost-saving programs for annual energy expenses. It is hoped the Photovoltaic program will result in overall savings for the NOS, help reduce the State's energy demands as relating to electrical power consumption, improve quality of life within the affected grid area as well as increase the energy efficiency of buildings at our venue. In addition, the potential to reduce operational expenses would have a tremendous effect on the ability of the NOS to service its community.

  1. Statistical Parameters for Describing Model Accuracy

    DTIC Science & Technology

    1989-03-20

    mean and the standard deviation, approximately characterizes the accuracy of the model, since the width of the confidence interval whose center is at...Using a modified version of Chebyshev’s inequality, a similar result is obtained for the upper bound of the confidence interval width for any

  2. Accuracy of non-Newtonian Lattice Boltzmann simulations

    NASA Astrophysics Data System (ADS)

    Conrad, Daniel; Schneider, Andreas; Böhle, Martin

    2015-11-01

    This work deals with the accuracy of non-Newtonian Lattice Boltzmann simulations. Previous work for Newtonian fluids indicate that, depending on the numerical value of the dimensionless collision frequency Ω, additional artificial viscosity is introduced, which negatively influences the accuracy. Since the non-Newtonian fluid behavior is incorporated through appropriate modeling of the dimensionless collision frequency, a Ω dependent error EΩ is introduced and its influence on the overall error is investigated. Here, simulations with the SRT and the MRT model are carried out for power-law fluids in order to numerically investigate the accuracy of non-Newtonian Lattice Boltzmann simulations. A goal of this accuracy analysis is to derive a recommendation for an optimal choice of the time step size and the simulation Mach number, respectively. For the non-Newtonian case, an error estimate for EΩ in the form of a functional is derived on the basis of a series expansion of the Lattice Boltzmann equation. This functional can be solved analytically for the case of the Hagen-Poiseuille channel flow of non-Newtonian fluids. With the help of the error functional, the prediction of the global error minimum of the velocity field is excellent in regions where the EΩ error is the dominant source of error. With an optimal simulation Mach number, the simulation is about one order of magnitude more accurate. Additionally, for both collision models a detailed study of the convergence behavior of the method in the non-Newtonian case is conducted. The results show that the simulation Mach number has a major impact on the convergence rate and second order accuracy is not preserved for every choice of the simulation Mach number.

  3. Impact of CCD camera SNR on polarimetric accuracy.

    PubMed

    Chen, Zhenyue; Wang, Xia; Pacheco, Shaun; Liang, Rongguang

    2014-11-10

    A comprehensive charge-coupled device (CCD) camera noise model is employed to study the impact of CCD camera signal-to-noise ratio (SNR) on polarimetric accuracy. The study shows that the standard deviations of the measured degree of linear polarization (DoLP) and angle of linear polarization (AoLP) are mainly dependent on the camera SNR. With increase in the camera SNR, both the measurement errors and the standard deviations caused by the CCD camera noise decrease. When the DoLP of the incident light is smaller than 0.1, the camera SNR should be at least 75 to achieve a measurement error of less than 0.01. When the input DoLP is larger than 0.5, a SNR of 15 is sufficient to achieve the same measurement accuracy. An experiment is carried out to verify the simulation results.

  4. High accuracy fuel flowmeter. Phase 2C and 3: The mass flowrate calibration of high accuracy fuel flowmeters

    NASA Technical Reports Server (NTRS)

    Craft, D. William

    1992-01-01

    A facility for the precise calibration of mass fuel flowmeters and turbine flowmeters located at AMETEK Aerospace Products Inc., Wilmington, Massachusetts is described. This facility is referred to as the Test and Calibration System (TACS). It is believed to be the most accurate test facility available for the calibration of jet engine fuel density measurement. The product of the volumetric flow rate measurement and the density measurement, results in a true mass flow rate determination. A dual-turbine flowmeter was designed during this program. The dual-turbine flowmeter was calibrated on the TACS to show the characteristics of this type of flowmeter. An angular momentum flowmeter was also calibrated on the TACS to demonstrate the accuracy of a true mass flowmeter having a 'state-of-the-art' design accuracy.

  5. Analysis of deformable image registration accuracy using computational modeling

    SciTech Connect

    Zhong Hualiang; Kim, Jinkoo; Chetty, Indrin J.

    2010-03-15

    Computer aided modeling of anatomic deformation, allowing various techniques and protocols in radiation therapy to be systematically verified and studied, has become increasingly attractive. In this study the potential issues in deformable image registration (DIR) were analyzed based on two numerical phantoms: One, a synthesized, low intensity gradient prostate image, and the other a lung patient's CT image data set. Each phantom was modeled with region-specific material parameters with its deformation solved using a finite element method. The resultant displacements were used to construct a benchmark to quantify the displacement errors of the Demons and B-Spline-based registrations. The results show that the accuracy of these registration algorithms depends on the chosen parameters, the selection of which is closely associated with the intensity gradients of the underlying images. For the Demons algorithm, both single resolution (SR) and multiresolution (MR) registrations required approximately 300 iterations to reach an accuracy of 1.4 mm mean error in the lung patient's CT image (and 0.7 mm mean error averaged in the lung only). For the low gradient prostate phantom, these algorithms (both SR and MR) required at least 1600 iterations to reduce their mean errors to 2 mm. For the B-Spline algorithms, best performance (mean errors of 1.9 mm for SR and 1.6 mm for MR, respectively) on the low gradient prostate was achieved using five grid nodes in each direction. Adding more grid nodes resulted in larger errors. For the lung patient's CT data set, the B-Spline registrations required ten grid nodes in each direction for highest accuracy (1.4 mm for SR and 1.5 mm for MR). The numbers of iterations or grid nodes required for optimal registrations depended on the intensity gradients of the underlying images. In summary, the performance of the Demons and B-Spline registrations have been quantitatively evaluated using numerical phantoms. The results show that parameter

  6. An automated method for the evaluation of the pointing accuracy of Sun-tracking devices

    NASA Astrophysics Data System (ADS)

    Baumgartner, Dietmar J.; Pötzi, Werner; Freislich, Heinrich; Strutzmann, Heinz; Veronig, Astrid M.; Rieder, Harald E.

    2017-03-01

    The accuracy of solar radiation measurements, for direct (DIR) and diffuse (DIF) radiation, depends significantly on the precision of the operational Sun-tracking device. Thus, rigid targets for instrument performance and operation have been specified for international monitoring networks, e.g., the Baseline Surface Radiation Network (BSRN) operating under the auspices of the World Climate Research Program (WCRP). Sun-tracking devices that fulfill these accuracy requirements are available from various instrument manufacturers; however, none of the commercially available systems comprise an automatic accuracy control system allowing platform operators to independently validate the pointing accuracy of Sun-tracking sensors during operation. Here we present KSO-STREAMS (KSO-SunTRackEr Accuracy Monitoring System), a fully automated, system-independent, and cost-effective system for evaluating the pointing accuracy of Sun-tracking devices. We detail the monitoring system setup, its design and specifications, and the results from its application to the Sun-tracking system operated at the Kanzelhöhe Observatory (KSO) Austrian radiation monitoring network (ARAD) site. The results from an evaluation campaign from March to June 2015 show that the tracking accuracy of the device operated at KSO lies within BSRN specifications (i.e., 0.1° tracking accuracy) for the vast majority of observations (99.8 %). The evaluation of manufacturer-specified active-tracking accuracies (0.02°), during periods with direct solar radiation exceeding 300 W m-2, shows that these are satisfied in 72.9 % of observations. Tracking accuracies are highest during clear-sky conditions and on days where prevailing clear-sky conditions are interrupted by frontal movement; in these cases, we obtain the complete fulfillment of BSRN requirements and 76.4 % of observations within manufacturer-specified active-tracking accuracies. Limitations to tracking surveillance arise during overcast conditions and

  7. Employment of sawtooth-shaped-function excitation signal and oversampling for improving resistance measurement accuracy

    NASA Astrophysics Data System (ADS)

    Lin, Ling; Li, Shujuan; Yan, Wenjuan; Li, Gang

    2016-10-01

    In order to achieve higher measurement accuracy of routine resistance without increasing the complexity and cost of the system circuit of existing methods, this paper presents a novel method that exploits a shaped-function excitation signal and oversampling technology. The excitation signal source for resistance measurement is modulated by the sawtooth-shaped-function signal, and oversampling technology is employed to increase the resolution and the accuracy of the measurement system. Compared with the traditional method of using constant amplitude excitation signal, this method can effectively enhance the measuring accuracy by almost one order of magnitude and reduce the root mean square error by 3.75 times under the same measurement conditions. The results of experiments show that the novel method can attain the aim of significantly improve the measurement accuracy of resistance on the premise of not increasing the system cost and complexity of the circuit, which is significantly valuable for applying in electronic instruments.

  8. Audiovisual biofeedback improves motion prediction accuracy

    PubMed Central

    Pollock, Sean; Lee, Danny; Keall, Paul; Kim, Taeho

    2013-01-01

    Purpose: The accuracy of motion prediction, utilized to overcome the system latency of motion management radiotherapy systems, is hampered by irregularities present in the patients’ respiratory pattern. Audiovisual (AV) biofeedback has been shown to reduce respiratory irregularities. The aim of this study was to test the hypothesis that AV biofeedback improves the accuracy of motion prediction. Methods: An AV biofeedback system combined with real-time respiratory data acquisition and MR images were implemented in this project. One-dimensional respiratory data from (1) the abdominal wall (30 Hz) and (2) the thoracic diaphragm (5 Hz) were obtained from 15 healthy human subjects across 30 studies. The subjects were required to breathe with and without the guidance of AV biofeedback during each study. The obtained respiratory signals were then implemented in a kernel density estimation prediction algorithm. For each of the 30 studies, five different prediction times ranging from 50 to 1400 ms were tested (150 predictions performed). Prediction error was quantified as the root mean square error (RMSE); the RMSE was calculated from the difference between the real and predicted respiratory data. The statistical significance of the prediction results was determined by the Student's t-test. Results: Prediction accuracy was considerably improved by the implementation of AV biofeedback. Of the 150 respiratory predictions performed, prediction accuracy was improved 69% (103/150) of the time for abdominal wall data, and 78% (117/150) of the time for diaphragm data. The average reduction in RMSE due to AV biofeedback over unguided respiration was 26% (p < 0.001) and 29% (p < 0.001) for abdominal wall and diaphragm respiratory motion, respectively. Conclusions: This study was the first to demonstrate that the reduction of respiratory irregularities due to the implementation of AV biofeedback improves prediction accuracy. This would result in increased efficiency of motion

  9. Accuracy of the LPM tracking system considering dynamic position changes.

    PubMed

    Ogris, Georg; Leser, Roland; Horsak, Brian; Kornfeind, Philipp; Heller, Mario; Baca, Arnold

    2012-01-01

    This study investigates the accuracy of the tracking system LPM (local position measurement). The goal was to determine detailed error values of the system in the context of sports performance analyses. Six moderately trained male soccer players (amateur level) performed 276 runs on three different courses at six different speeds. Additionally, ten small-sided game plays were carried out. All runs and game plays were recorded with the LPM tracking system and the motion capture system VICON simultaneously. VICON served as the reference system. The absolute error of all LPM position estimations was on average 23.4±20.7 cm. The estimation for average velocities varied between 0.01 km h(-1) and 0.23 km h(-1), the maximum speed estimations differed by up to 2.71 km h(-1). In addition, the results showed that the accuracy of the LPM system is highly dependent on the instantaneous dynamics of the player and decreases in the margins of the observation field. These dependencies were quantified. Considering commonly used applications of position tracking systems in sports (Leser, Ogris, & Baca, 2011), the accuracy of LPM is acceptable for position and velocity estimations. The system provides valuable results for average velocities but seems to be far less reliable when dealing with high dynamic movements and measuring instantaneous velocities.

  10. A Framework for the Objective Assessment of Registration Accuracy

    PubMed Central

    Simonetti, Flavio; Foroni, Roberto Israel

    2014-01-01

    Validation and accuracy assessment are the main bottlenecks preventing the adoption of image processing algorithms in the clinical practice. In the classical approach, a posteriori analysis is performed through objective metrics. In this work, a different approach based on Petri nets is proposed. The basic idea consists in predicting the accuracy of a given pipeline based on the identification and characterization of the sources of inaccuracy. The concept is demonstrated on a case study: intrasubject rigid and affine registration of magnetic resonance images. Both synthetic and real data are considered. While synthetic data allow the benchmarking of the performance with respect to the ground truth, real data enable to assess the robustness of the methodology in real contexts as well as to determine the suitability of the use of synthetic data in the training phase. Results revealed a higher correlation and a lower dispersion among the metrics for simulated data, while the opposite trend was observed for pathologic ones. Results show that the proposed model not only provides a good prediction performance but also leads to the optimization of the end-to-end chain in terms of accuracy and robustness, setting the ground for its generalization to different and more complex scenarios. PMID:24659997

  11. Analyzing thematic maps and mapping for accuracy

    USGS Publications Warehouse

    Rosenfield, G.H.

    1982-01-01

    Two problems which exist while attempting to test the accuracy of thematic maps and mapping are: (1) evaluating the accuracy of thematic content, and (2) evaluating the effects of the variables on thematic mapping. Statistical analysis techniques are applicable to both these problems and include techniques for sampling the data and determining their accuracy. In addition, techniques for hypothesis testing, or inferential statistics, are used when comparing the effects of variables. A comprehensive and valid accuracy test of a classification project, such as thematic mapping from remotely sensed data, includes the following components of statistical analysis: (1) sample design, including the sample distribution, sample size, size of the sample unit, and sampling procedure; and (2) accuracy estimation, including estimation of the variance and confidence limits. Careful consideration must be given to the minimum sample size necessary to validate the accuracy of a given. classification category. The results of an accuracy test are presented in a contingency table sometimes called a classification error matrix. Usually the rows represent the interpretation, and the columns represent the verification. The diagonal elements represent the correct classifications. The remaining elements of the rows represent errors by commission, and the remaining elements of the columns represent the errors of omission. For tests of hypothesis that compare variables, the general practice has been to use only the diagonal elements from several related classification error matrices. These data are arranged in the form of another contingency table. The columns of the table represent the different variables being compared, such as different scales of mapping. The rows represent the blocking characteristics, such as the various categories of classification. The values in the cells of the tables might be the counts of correct classification or the binomial proportions of these counts divided by

  12. Accuracy and robustness evaluation in stereo matching

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc M.; Hanca, Jan; Lu, Shao-Ping; Schelkens, Peter; Munteanu, Adrian

    2016-09-01

    Stereo matching has received a lot of attention from the computer vision community, thanks to its wide range of applications. Despite of the large variety of algorithms that have been proposed so far, it is not trivial to select suitable algorithms for the construction of practical systems. One of the main problems is that many algorithms lack sufficient robustness when employed in various operational conditions. This problem is due to the fact that most of the proposed methods in the literature are usually tested and tuned to perform well on one specific dataset. To alleviate this problem, an extensive evaluation in terms of accuracy and robustness of state-of-the-art stereo matching algorithms is presented. Three datasets (Middlebury, KITTI, and MPEG FTV) representing different operational conditions are employed. Based on the analysis, improvements over existing algorithms have been proposed. The experimental results show that our improved versions of cross-based and cost volume filtering algorithms outperform the original versions with large margins on Middlebury and KITTI datasets. In addition, the latter of the two proposed algorithms ranks itself among the best local stereo matching approaches on the KITTI benchmark. Under evaluations using specific settings for depth-image-based-rendering applications, our improved belief propagation algorithm is less complex than MPEG's FTV depth estimation reference software (DERS), while yielding similar depth estimation performance. Finally, several conclusions on stereo matching algorithms are also presented.

  13. Accuracy Improvement for Predicting Parkinson's Disease Progression.

    PubMed

    Nilashi, Mehrbakhsh; Ibrahim, Othman; Ahani, Ali

    2016-09-30

    Parkinson's disease (PD) is a member of a larger group of neuromotor diseases marked by the progressive death of dopamineproducing cells in the brain. Providing computational tools for Parkinson disease using a set of data that contains medical information is very desirable for alleviating the symptoms that can help the amount of people who want to discover the risk of disease at an early stage. This paper proposes a new hybrid intelligent system for the prediction of PD progression using noise removal, clustering and prediction methods. Principal Component Analysis (PCA) and Expectation Maximization (EM) are respectively employed to address the multi-collinearity problems in the experimental datasets and clustering the data. We then apply Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Regression (SVR) for prediction of PD progression. Experimental results on public Parkinson's datasets show that the proposed method remarkably improves the accuracy of prediction of PD progression. The hybrid intelligent system can assist medical practitioners in the healthcare practice for early detection of Parkinson disease.

  14. Accuracy of References in Ten Library Science Journals.

    ERIC Educational Resources Information Center

    Pope, Nancy N.

    1992-01-01

    A study of 100 article citations from 11 library science journals showed only 45 article citations that were completely free of errors, while 11 had major errors--i.e., errors preventing or hindering location of the reference--and the remaining 44 had minor errors. Citation accuracy in library science journals appears similar to accuracy in other…

  15. Astronomic Position Accuracy Capability Study.

    DTIC Science & Technology

    1979-10-01

    portion of F. E. Warren AFB, Wyoming. The three points were called THEODORE ECC , TRACY, and JIM and consisted of metal tribrachs plastered to cinder...sets were computed as a deviation from the standard. Accuracy figures were determined from these residuals. Homo - geneity of variances was tested using

  16. The hidden KPI registration accuracy.

    PubMed

    Shorrosh, Paul

    2011-09-01

    Determining the registration accuracy rate is fundamental to improving revenue cycle key performance indicators. A registration quality assurance (QA) process allows errors to be corrected before bills are sent and helps registrars learn from their mistakes. Tools are available to help patient access staff who perform registration QA manually.

  17. Inventory accuracy in 60 days!

    PubMed

    Miller, G J

    1997-08-01

    Despite great advances in manufacturing technology and management science, thousands of organizations still don't have a handle on basic inventory accuracy. Many companies don't even measure it properly, or at all, and lack corrective action programs to improve it. This article offers an approach that has proven successful a number of times, when companies were quite serious about making improvements. Not only can it be implemented, but also it can likely be implemented within 60 days per area, if properly managed. The hardest part is selling people on the need to improve and then keeping them motivated. The net cost of such a program? Probably less than nothing, since the benefits gained usually far exceed the costs. Improved inventory accuracy can aid in enhancing customer service, determining purchasing and manufacturing priorities, reducing operating costs, and increasing the accuracy of financial records. This article also addresses the gap in contemporary literature regarding accuracy program features for repetitive, JIT, cellular, and process- and project-oriented environments.

  18. Seasonal Effects on GPS PPP Accuracy

    NASA Astrophysics Data System (ADS)

    Saracoglu, Aziz; Ugur Sanli, D.

    2016-04-01

    GPS Precise Point Positioning (PPP) is now routinely used in many geophysical applications. Static positioning and 24 h data are requested for high precision results however real life situations do not always let us collect 24 h data. Thus repeated GPS surveys of 8-10 h observation sessions are still used by some research groups. Positioning solutions from shorter data spans are subject to various systematic influences, and the positioning quality as well as the estimated velocity is degraded. Researchers pay attention to the accuracy of GPS positions and of the estimated velocities derived from short observation sessions. Recently some research groups turned their attention to the study of seasonal effects (i.e. meteorological seasons) on GPS solutions. Up to now usually regional studies have been reported. In this study, we adopt a global approach and study the various seasonal effects (including the effect of the annual signal) on GPS solutions produced from short observation sessions. We use the PPP module of the NASA/JPL's GIPSY/OASIS II software and globally distributed GPS stations' data of the International GNSS Service. Accuracy studies previously performed with 10-30 consecutive days of continuous data. Here, data from each month of a year, incorporating two years in succession, is used in the analysis. Our major conclusion is that a reformulation for the GPS positioning accuracy is necessary when taking into account the seasonal effects, and typical one term accuracy formulation is expanded to a two-term one.

  19. Navigation Accuracy Guidelines for Orbital Formation Flying

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Alfriend, Kyle T.

    2004-01-01

    Some simple guidelines based on the accuracy in determining a satellite formation s semi-major axis differences are useful in making preliminary assessments of the navigation accuracy needed to support such missions. These guidelines are valid for any elliptical orbit, regardless of eccentricity. Although maneuvers required for formation establishment, reconfiguration, and station-keeping require accurate prediction of the state estimate to the maneuver time, and hence are directly affected by errors in all the orbital elements, experience has shown that determination of orbit plane orientation and orbit shape to acceptable levels is less challenging than the determination of orbital period or semi-major axis. Furthermore, any differences among the member s semi-major axes are undesirable for a satellite formation, since it will lead to differential along-track drift due to period differences. Since inevitable navigation errors prevent these differences from ever being zero, one may use the guidelines this paper presents to determine how much drift will result from a given relative navigation accuracy, or conversely what navigation accuracy is required to limit drift to a given rate. Since the guidelines do not account for non-two-body perturbations, they may be viewed as useful preliminary design tools, rather than as the basis for mission navigation requirements, which should be based on detailed analysis of the mission configuration, including all relevant sources of uncertainty.

  20. Medial Patellofemoral Ligament Reconstruction Femoral Tunnel Accuracy

    PubMed Central

    Hiemstra, Laurie A.; Kerslake, Sarah; Lafave, Mark

    2017-01-01

    Background: Medial patellofemoral ligament (MPFL) reconstruction is a procedure aimed to reestablish the checkrein to lateral patellar translation in patients with symptomatic patellofemoral instability. Correct femoral tunnel position is thought to be crucial to successful MPFL reconstruction, but the accuracy of this statement in terms of patient outcomes has not been tested. Purpose: To assess the accuracy of femoral tunnel placement in an MPFL reconstruction cohort and to determine the correlation between tunnel accuracy and a validated disease-specific, patient-reported quality-of-life outcome measure. Study Design: Case series; Level of evidence, 4. Methods: Between June 2008 and February 2014, a total of 206 subjects underwent an MPFL reconstruction. Lateral radiographs were measured to determine the accuracy of the femoral tunnel by measuring the distance from the center of the femoral tunnel to the Schöttle point. Banff Patella Instability Instrument (BPII) scores were collected a mean 24 months postoperatively. Results: A total of 155 (79.5%) subjects had adequate postoperative lateral radiographs and complete BPII scores. The mean duration of follow-up (±SD) was 24.4 ± 8.2 months (range, 12-74 months). Measurement from the center of the femoral tunnel to the Schöttle point resulted in 143 (92.3%) tunnels being categorized as “good” or “ideal.” There were 8 failures in the cohort, none of which occurred in malpositioned tunnels. The mean distance from the center of the MPFL tunnel to the center of the Schöttle point was 5.9 ± 4.2 mm (range, 0.5-25.9 mm). The mean postoperative BPII score was 65.2 ± 22.5 (range, 9.2-100). Pearson r correlation demonstrated no statistically significant relationship between accuracy of femoral tunnel position and BPII score (r = –0.08; 95% CI, –0.24 to 0.08). Conclusion: There was no evidence of a correlation between the accuracy of MPFL reconstruction femoral tunnel in relation to the Schöttle point and

  1. The effect of speed-accuracy strategy on response interference control in Parkinson's disease.

    PubMed

    Wylie, S A; van den Wildenberg, W P M; Ridderinkhof, K R; Bashore, T R; Powell, V D; Manning, C A; Wooten, G F

    2009-07-01

    Studies that used conflict paradigms such as the Eriksen Flanker task show that many individuals with Parkinson's disease (PD) have pronounced difficulty resolving the conflict that arises from the simultaneous activation of mutually exclusive responses. This finding fits well with contemporary views that postulate a key role for the basal ganglia in action selection. The present experiment aims to specify the cognitive processes that underlie action selection deficits among PD patients in the context of variations in speed-accuracy strategy. PD patients (n=28) and healthy controls (n=17) performed an arrow version of the flanker task under task instructions that either emphasized speed or accuracy of responses. Reaction time (RT) and accuracy rates decreased with speed compared to accuracy instructions, although to a lesser extent for the PD group. Differences in flanker interference effects among PD and healthy controls depended on speed-accuracy strategy. Compared to the healthy controls, PD patients showed larger flanker interference effects under speed stress. RT distribution analyses suggested that PD patients have greater difficulty suppressing incorrect response activation when pressing for speed. These initial findings point to an important interaction between strategic and computational aspects of interference control in accounting for cognitive impairments of PD. The results are also compatible with recent brain imaging studies that demonstrate basal ganglia activity to co-vary with speed-accuracy adjustments.

  2. Improved accuracies for satellite tracking

    NASA Technical Reports Server (NTRS)

    Kammeyer, P. C.; Fiala, A. D.; Seidelmann, P. K.

    1991-01-01

    A charge coupled device (CCD) camera on an optical telescope which follows the stars can be used to provide high accuracy comparisons between the line of sight to a satellite, over a large range of satellite altitudes, and lines of sight to nearby stars. The CCD camera can be rotated so the motion of the satellite is down columns of the CCD chip, and charge can be moved from row to row of the chip at a rate which matches the motion of the optical image of the satellite across the chip. Measurement of satellite and star images, together with accurate timing of charge motion, provides accurate comparisons of lines of sight. Given lines of sight to stars near the satellite, the satellite line of sight may be determined. Initial experiments with this technique, using an 18 cm telescope, have produced TDRS-4 observations which have an rms error of 0.5 arc second, 100 m at synchronous altitude. Use of a mosaic of CCD chips, each having its own rate of charge motion, in the focal place of a telescope would allow point images of a geosynchronous satellite and of stars to be formed simultaneously in the same telescope. The line of sight of such a satellite could be measured relative to nearby star lines of sight with an accuracy of approximately 0.03 arc second. Development of a star catalog with 0.04 arc second rms accuracy and perhaps ten stars per square degree would allow determination of satellite lines of sight with 0.05 arc second rms absolute accuracy, corresponding to 10 m at synchronous altitude. Multiple station time transfers through a communications satellite can provide accurate distances from the satellite to the ground stations. Such observations can, if calibrated for delays, determine satellite orbits to an accuracy approaching 10 m rms.

  3. Effects of sample survey design on the accuracy of classification tree models in species distribution models

    USGS Publications Warehouse

    Edwards, T.C.; Cutler, D.R.; Zimmermann, N.E.; Geiser, L.; Moisen, G.G.

    2006-01-01

    We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE tree models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE tree models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen species, with 11 of the 12 possible species and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification tree structures also differed considerably both among and within the modelled species, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE tree models ranged from only 20% to 38%, indicating the classification trees fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys. ?? 2006 Elsevier B.V. All rights reserved.

  4. Nationwide forestry applications program. Analysis of forest classification accuracy

    NASA Technical Reports Server (NTRS)

    Congalton, R. G.; Mead, R. A.; Oderwald, R. G.; Heinen, J. (Principal Investigator)

    1981-01-01

    The development of LANDSAT classification accuracy assessment techniques, and of a computerized system for assessing wildlife habitat from land cover maps are considered. A literature review on accuracy assessment techniques and an explanation for the techniques development under both projects are included along with listings of the computer programs. The presentations and discussions at the National Working Conference on LANDSAT Classification Accuracy are summarized. Two symposium papers which were published on the results of this project are appended.

  5. Airborne Topographic Mapper Calibration Procedures and Accuracy Assessment

    NASA Technical Reports Server (NTRS)

    Martin, Chreston F.; Krabill, William B.; Manizade, Serdar S.; Russell, Rob L.; Sonntag, John G.; Swift, Robert N.; Yungel, James K.

    2012-01-01

    Description of NASA Airborn Topographic Mapper (ATM) lidar calibration procedures including analysis of the accuracy and consistancy of various ATM instrument parameters and the resulting influence on topographic elevation measurements. The ATM elevations measurements from a nominal operating altitude 500 to 750 m above the ice surface was found to be: Horizontal Accuracy 74 cm, Horizontal Precision 14 cm, Vertical Accuracy 6.6 cm, Vertical Precision 3 cm.

  6. Matters of Accuracy and Conventionality: Prior Accuracy Guides Children's Evaluations of Others' Actions

    ERIC Educational Resources Information Center

    Scofield, Jason; Gilpin, Ansley Tullos; Pierucci, Jillian; Morgan, Reed

    2013-01-01

    Studies show that children trust previously reliable sources over previously unreliable ones (e.g., Koenig, Clement, & Harris, 2004). However, it is unclear from these studies whether children rely on accuracy or conventionality to determine the reliability and, ultimately, the trustworthiness of a particular source. In the current study, 3- and…

  7. MAPPING SPATIAL THEMATIC ACCURACY WITH FUZZY SETS

    EPA Science Inventory

    Thematic map accuracy is not spatially homogenous but variable across a landscape. Properly analyzing and representing spatial pattern and degree of thematic map accuracy would provide valuable information for using thematic maps. However, current thematic map accuracy measures (...

  8. Method for improving accuracy in full evaporation headspace analysis.

    PubMed

    Xie, Wei-Qi; Chai, Xin-Sheng

    2017-03-21

    We report a new headspace analytical method in which multiple headspace extraction is incorporated with the full evaporation technique. The pressure uncertainty caused by the solid content change in the samples has a great impact to the measurement accuracy in the conventional full evaporation headspace analysis. The results (using ethanol solution as the model sample) showed that the present technique is effective to minimize such a problem. The proposed full evaporation multiple headspace extraction analysis technique is also automated and practical, and which could greatly broaden the applications of the full-evaporation-based headspace analysis. This article is protected by copyright. All rights reserved.

  9. Applications and accuracy of the parallel diagonal dominant algorithm

    NASA Technical Reports Server (NTRS)

    Sun, Xian-He

    1993-01-01

    The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric, and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that the analysis gives a good bound on the relative error, and the algorithm is a good candidate for the emerging massively parallel machines.

  10. Speed versus accuracy in collective decision making.

    PubMed Central

    Franks, Nigel R; Dornhaus, Anna; Fitzsimmons, Jon P; Stevens, Martin

    2003-01-01

    We demonstrate a speed versus accuracy trade-off in collective decision making. House-hunting ant colonies choose a new nest more quickly in harsh conditions than in benign ones and are less discriminating. The errors that occur in a harsh environment are errors of judgement not errors of omission because the colonies have discovered all of the alternative nests before they initiate an emigration. Leptothorax albipennis ants use quorum sensing in their house hunting. They only accept a nest, and begin rapidly recruiting members of their colony, when they find within it a sufficient number of their nest-mates. Here we show that these ants can lower their quorum thresholds between benign and harsh conditions to adjust their speed-accuracy trade-off. Indeed, in harsh conditions these ants rely much more on individual decision making than collective decision making. Our findings show that these ants actively choose to take their time over judgements and employ collective decision making in benign conditions when accuracy is more important than speed. PMID:14667335

  11. Determination of GPS orbits to submeter accuracy

    NASA Technical Reports Server (NTRS)

    Bertiger, W. I.; Lichten, S. M.; Katsigris, E. C.

    1988-01-01

    Orbits for satellites of the Global Positioning System (GPS) were determined with submeter accuracy. Tests used to assess orbital accuracy include orbit comparisons from independent data sets, orbit prediction, ground baseline determination, and formal errors. One satellite tracked 8 hours each day shows rms error below 1 m even when predicted more than 3 days outside of a 1-week data arc. Differential tracking of the GPS satellites in high Earth orbit provides a powerful relative positioning capability, even when a relatively small continental U.S. fiducial tracking network is used with less than one-third of the full GPS constellation. To demonstrate this capability, baselines of up to 2000 km in North America were also determined with the GPS orbits. The 2000 km baselines show rms daily repeatability of 0.3 to 2 parts in 10 to the 8th power and agree with very long base interferometry (VLBI) solutions at the level of 1.5 parts in 10 to the 8th power. This GPS demonstration provides an opportunity to test different techniques for high-accuracy orbit determination for high Earth orbiters. The best GPS orbit strategies included data arcs of at least 1 week, process noise models for tropospheric fluctuations, estimation of GPS solar pressure coefficients, and combine processing of GPS carrier phase and pseudorange data. For data arc of 2 weeks, constrained process noise models for GPS dynamic parameters significantly improved the situation.

  12. Improved Discrimination of Influenza Forecast Accuracy Using Consecutive Predictions

    PubMed Central

    Shaman, Jeffrey; Kandula, Sasikiran

    2015-01-01

    Introduction: The ability to predict the growth and decline of infectious disease incidence has advanced considerably in recent years. In particular, accurate forecasts of influenza epidemiology have been developed using a number of approaches. Methods: Within our own group we produce weekly operational real-time forecasts of influenza at the municipal and state level in the U.S. These forecasts are generated using ensemble simulations depicting local influenza transmission dynamics, which have been optimized prior to forecast with observations of influenza incidence and data assimilation methods. The expected accuracy of a given forecast can be inferred in real-time through quantification of the agreement (e.g. the variance) among the ensemble of simulations. Results: Here we show that forecast expected accuracy can be further discriminated with the additional consideration of the streak or persistence of the forecast—the number of consecutive weeks the forecast has converged to the same outcome. Discussion: The findings indicate that the use of both the streak and ensemble agreement provides a more detailed and informative assessment of forecast expected accuracy. PMID:26512336

  13. Stability and accuracy control of k · p parameters

    NASA Astrophysics Data System (ADS)

    Bastos, Carlos M. O.; Sabino, Fernando P.; Faria Junior, Paulo E.; Campos, Tiago; Da Silva, Juarez L. F.; Sipahi, Guilherme M.

    2016-10-01

    The k · p method is a successful approach to obtain band structure, optical and transport properties of semiconductors and it depends on external parameters that are obtained either from experiments, tight binding or ab initio calculations. Despite the widespread use of the k · p method, a systematic analysis of the stability and the accuracy of its parameters is not usual in the literature. In this work, we report a theoretical framework to determine the k · p parameters from state-of-the-art hybrid density functional theory including spin-orbit coupling, providing a calculation where the gap and spin-orbit energy splitting are in agreement with the experimental values. The accuracy of the set of parameters is enhanced by fitting over several directions at once, minimizing the overall deviation from the original data. This strategy allows us to systematically evaluate the stability, preserving the accuracy of the parameters, providing a tool to determine optimal parameters for specific ranges around the Γ-point. To prove our concept, we investigate the zinc blende GaAs that shows results in excellent agreement with the most reliable data in the literature.

  14. Standardized accuracy assessment of the calypso wireless transponder tracking system

    NASA Astrophysics Data System (ADS)

    Franz, A. M.; Schmitt, D.; Seitel, A.; Chatrasingh, M.; Echner, G.; Oelfke, U.; Nill, S.; Birkfellner, W.; Maier-Hein, L.

    2014-11-01

    Electromagnetic (EM) tracking allows localization of small EM sensors in a magnetic field of known geometry without line-of-sight. However, this technique requires a cable connection to the tracked object. A wireless alternative based on magnetic fields, referred to as transponder tracking, has been proposed by several authors. Although most of the transponder tracking systems are still in an early stage of development and not ready for clinical use yet, Varian Medical Systems Inc. (Palo Alto, California, USA) presented the Calypso system for tumor tracking in radiation therapy which includes transponder technology. But it has not been used for computer-assisted interventions (CAI) in general or been assessed for accuracy in a standardized manner, so far. In this study, we apply a standardized assessment protocol presented by Hummel et al (2005 Med. Phys. 32 2371-9) to the Calypso system for the first time. The results show that transponder tracking with the Calypso system provides a precision and accuracy below 1 mm in ideal clinical environments, which is comparable with other EM tracking systems. Similar to other systems the tracking accuracy was affected by metallic distortion, which led to errors of up to 3.2 mm. The potential of the wireless transponder tracking technology for use in many future CAI applications can be regarded as extremely high.

  15. High accuracy and visibility-consistent dense multiview stereo.

    PubMed

    Vu, Hoang-Hiep; Labatut, Patrick; Pons, Jean-Philippe; Keriven, Renaud

    2012-05-01

    Since the initial comparison of Seitz et al., the accuracy of dense multiview stereovision methods has been increasing steadily. A number of limitations, however, make most of these methods not suitable to outdoor scenes taken under uncontrolled imaging conditions. The present work consists of a complete dense multiview stereo pipeline which circumvents these limitations, being able to handle large-scale scenes without sacrificing accuracy. Highly detailed reconstructions are produced within very reasonable time thanks to two key stages in our pipeline: a minimum s-t cut optimization over an adaptive domain that robustly and efficiently filters a quasidense point cloud from outliers and reconstructs an initial surface by integrating visibility constraints, followed by a mesh-based variational refinement that captures small details, smartly handling photo-consistency, regularization, and adaptive resolution. The pipeline has been tested over a wide range of scenes: from classic compact objects taken in a laboratory setting, to outdoor architectural scenes, landscapes, and cultural heritage sites. The accuracy of its reconstructions has also been measured on the dense multiview benchmark proposed by Strecha et al., showing the results to compare more than favorably with the current state-of-the-art methods.

  16. Accuracy of distance measurements in biplane angiography

    NASA Astrophysics Data System (ADS)

    Toennies, Klaus D.; Oishi, Satoru; Koster, David; Schroth, Gerhard

    1997-05-01

    Distance measurements of the vascular system of the brain can be derived from biplanar digital subtraction angiography (2p-DSA). The measurements are used for planning of minimal invasive surgical procedures. Our 90 degree-fixed-angle G- ring angiography system has the potential of acquiring pairs of such images with high geometric accuracy. The sizes of vessels and aneurysms are estimated applying a fast and accurate extraction method in order to select an appropriate surgical strategy. Distance computation from 2p-DSA is carried out in three steps. First, the boundary of the structure to be measured is detected based on zero-crossings and closeness to user-specified end points. Subsequently, the 3D location of the center of the structure is computed from the centers of gravity of its two projections. This location is used to reverse the magnification factor caused by the cone-shaped projection of the x-rays. Since exact measurements of possibly very small structures are crucial to the usefulness in surgical planning, we identified mechanical and computational influences on the geometry which may have an impact on the measurement accuracy. A study with phantoms is presented distinguishing between the different effects and enabling the computation of an optimal overall exactness. Comparing this optimum with results of distance measurements on phantoms whose exact size and shape is known, we found, that the measurement error for structures of size of 20 mm was less than 0.05 mm on average and 0.50 mm at maximum. The maximum achievable accuracy of 0.15 mm was in most cases exceeded by less than 0.15 mm. This accuracy surpasses by far the requirements for the above mentioned surgery application. The mechanic accuracy of the fixed-angle biplanar system meets the requirements for computing a 3D reconstruction of the small vessels of the brain. It also indicates, that simple measurements will be possible on systems being less accurate.

  17. 15. Detail showing lower chord pinconnected to vertical member, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Detail showing lower chord pin-connected to vertical member, showing floor beam riveted to extension of vertical member below pin-connection, and showing brackets supporting cantilevered sidewalk. View to southwest. - Selby Avenue Bridge, Spanning Short Line Railways track at Selby Avenue between Hamline & Snelling Avenues, Saint Paul, Ramsey County, MN

  18. Accuracy assessment of seven global land cover datasets over China

    NASA Astrophysics Data System (ADS)

    Yang, Yongke; Xiao, Pengfeng; Feng, Xuezhi; Li, Haixing

    2017-03-01

    Land cover (LC) is the vital foundation to Earth science. Up to now, several global LC datasets have arisen with efforts of many scientific communities. To provide guidelines for data usage over China, nine LC maps from seven global LC datasets (IGBP DISCover, UMD, GLC, MCD12Q1, GLCNMO, CCI-LC, and GlobeLand30) were evaluated in this study. First, we compared their similarities and discrepancies in both area and spatial patterns, and analysed their inherent relations to data sources and classification schemes and methods. Next, five sets of validation sample units (VSUs) were collected to calculate their accuracy quantitatively. Further, we built a spatial analysis model and depicted their spatial variation in accuracy based on the five sets of VSUs. The results show that, there are evident discrepancies among these LC maps in both area and spatial patterns. For LC maps produced by different institutes, GLC 2000 and CCI-LC 2000 have the highest overall spatial agreement (53.8%). For LC maps produced by same institutes, overall spatial agreement of CCI-LC 2000 and 2010, and MCD12Q1 2001 and 2010 reach up to 99.8% and 73.2%, respectively; while more efforts are still needed if we hope to use these LC maps as time series data for model inputting, since both CCI-LC and MCD12Q1 fail to represent the rapid changing trend of several key LC classes in the early 21st century, in particular urban and built-up, snow and ice, water bodies, and permanent wetlands. With the highest spatial resolution, the overall accuracy of GlobeLand30 2010 is 82.39%. For the other six LC datasets with coarse resolution, CCI-LC 2010/2000 has the highest overall accuracy, and following are MCD12Q1 2010/2001, GLC 2000, GLCNMO 2008, IGBP DISCover, and UMD in turn. Beside that all maps exhibit high accuracy in homogeneous regions; local accuracies in other regions are quite different, particularly in Farming-Pastoral Zone of North China, mountains in Northeast China, and Southeast Hills. Special

  19. Thermocouple Calibration and Accuracy in a Materials Testing Laboratory

    NASA Technical Reports Server (NTRS)

    Lerch, B. A.; Nathal, M. V.; Keller, D. J.

    2002-01-01

    A consolidation of information has been provided that can be used to define procedures for enhancing and maintaining accuracy in temperature measurements in materials testing laboratories. These studies were restricted to type R and K thermocouples (TCs) tested in air. Thermocouple accuracies, as influenced by calibration methods, thermocouple stability, and manufacturer's tolerances were all quantified in terms of statistical confidence intervals. By calibrating specific TCs the benefits in accuracy can be as great as 6 C or 5X better compared to relying on manufacturer's tolerances. The results emphasize strict reliance on the defined testing protocol and on the need to establish recalibration frequencies in order to maintain these levels of accuracy.

  20. Accuracy of implant impression techniques.

    PubMed

    Assif, D; Marshak, B; Schmidt, A

    1996-01-01

    Three impression techniques were assessed for accuracy in a laboratory cast that simulated clinical practice. The first technique used autopolymerizing acrylic resin to splint the transfer copings. The second involved splinting of the transfer copings directly to an acrylic resin custom tray. In the third, only impression material was used to orient the transfer copings. The accuracy of stone casts with implant analogs was measured against a master framework. The fit of the framework on the casts was tested using strain gauges. The technique using acrylic resin to splint transfer copings in the impression material was significantly more accurate than the two other techniques. Stresses observed in the framework are described and discussed with suggestions to improve clinical and laboratory techniques.

  1. Enhancing and evaluating diagnostic accuracy.

    PubMed

    Swets, J A; Getty, D J; Pickett, R M; D'Orsi, C J; Seltzer, S E; McNeil, B J

    1991-01-01

    Techniques that may enhance diagnostic accuracy in clinical settings were tested in the context of mammography. Statistical information about the relevant features among those visible in a mammogram and about their relative importances in the diagnosis of breast cancer was the basis of two decision aids for radiologists: a checklist that guides the radiologist in assigning a scale value to each significant feature of the images of a particular case, and a computer program that merges those scale values optimally to estimate a probability of malignancy. A test set of approximately 150 proven cases (including normals and benign and malignant lesions) was interpreted by six radiologists, first in their usual manner and later with the decision aids. The enhancing effect of these feature-analytic techniques was analyzed across subsets of cases that were restricted progressively to more and more difficult cases, where difficulty was defined in terms of the radiologists' judgements in the standard reading condition. Accuracy in both standard and enhanced conditions decreased regularly and substantially as case difficulty increased, but differentially, such that the enhancement effect grew regularly and substantially. For the most difficult case sets, the observed increases in accuracy translated into an increase of about 0.15 in sensitivity (true-positive proportion) for a selected specificity (true-negative proportion) of 0.85 or a similar increase in specificity for a selected sensitivity of 0.85. That measured accuracy can depend on case-set difficulty to different degrees for two diagnostic approaches has general implications for evaluation in clinical medicine. Comparative, as well as absolute, assessments of diagnostic performances--for example, of alternative imaging techniques--may be distorted by inadequate treatments of this experimental variable. Subset analysis, as defined and illustrated here, can be useful in alleviating the problem.

  2. On the Accuracy of Genomic Selection

    PubMed Central

    Rabier, Charles-Elie; Barre, Philippe; Asp, Torben; Charmet, Gilles; Mangin, Brigitte

    2016-01-01

    Genomic selection is focused on prediction of breeding values of selection candidates by means of high density of markers. It relies on the assumption that all quantitative trait loci (QTLs) tend to be in strong linkage disequilibrium (LD) with at least one marker. In this context, we present theoretical results regarding the accuracy of genomic selection, i.e., the correlation between predicted and true breeding values. Typically, for individuals (so-called test individuals), breeding values are predicted by means of markers, using marker effects estimated by fitting a ridge regression model to a set of training individuals. We present a theoretical expression for the accuracy; this expression is suitable for any configurations of LD between QTLs and markers. We also introduce a new accuracy proxy that is free of the QTL parameters and easily computable; it outperforms the proxies suggested in the literature, in particular, those based on an estimated effective number of independent loci (Me). The theoretical formula, the new proxy, and existing proxies were compared for simulated data, and the results point to the validity of our approach. The calculations were also illustrated on a new perennial ryegrass set (367 individuals) genotyped for 24,957 single nucleotide polymorphisms (SNPs). In this case, most of the proxies studied yielded similar results because of the lack of markers for coverage of the entire genome (2.7 Gb). PMID:27322178

  3. Factors Influencing Pronunciation Accuracy: L1 Negative Transfer, Task Variables and Individual Aptitude

    ERIC Educational Resources Information Center

    Liu, Qian

    2011-01-01

    This paper investigates the influence of three factors on pronunciation accuracy of Chinese adult foreign language learners. Ten target sounds including phonemes and syllables are included in the pre-test, an analysis of which shows that the mispronunciation of the randomly chosen target sounds mainly results from L1 negative transfer. It is…

  4. High accuracy operon prediction method based on STRING database scores.

    PubMed

    Taboada, Blanca; Verde, Cristina; Merino, Enrique

    2010-07-01

    We present a simple and highly accurate computational method for operon prediction, based on intergenic distances and functional relationships between the protein products of contiguous genes, as defined by STRING database (Jensen,L.J., Kuhn,M., Stark,M., Chaffron,S., Creevey,C., Muller,J., Doerks,T., Julien,P., Roth,A., Simonovic,M. et al. (2009) STRING 8-a global view on proteins and their functional interactions in 630 organisms. Nucleic Acids Res., 37, D412-D416). These two parameters were used to train a neural network on a subset of experimentally characterized Escherichia coli and Bacillus subtilis operons. Our predictive model was successfully tested on the set of experimentally defined operons in E. coli and B. subtilis, with accuracies of 94.6 and 93.3%, respectively. As far as we know, these are the highest accuracies ever obtained for predicting bacterial operons. Furthermore, in order to evaluate the predictable accuracy of our model when using an organism's data set for the training procedure, and a different organism's data set for testing, we repeated the E. coli operon prediction analysis using a neural network trained with B. subtilis data, and a B. subtilis analysis using a neural network trained with E. coli data. Even for these cases, the accuracies reached with our method were outstandingly high, 91.5 and 93%, respectively. These results show the potential use of our method for accurately predicting the operons of any other organism. Our operon predictions for fully-sequenced genomes are available at http://operons.ibt.unam.mx/OperonPredictor/.

  5. Accuracy of stream habitat interpolations across spatial scales

    USGS Publications Warehouse

    Sheehan, Kenneth R.; Welsh, Stuart

    2013-01-01

    Stream habitat data are often collected across spatial scales because relationships among habitat, species occurrence, and management plans are linked at multiple spatial scales. Unfortunately, scale is often a factor limiting insight gained from spatial analysis of stream habitat data. Considerable cost is often expended to collect data at several spatial scales to provide accurate evaluation of spatial relationships in streams. To address utility of single scale set of stream habitat data used at varying scales, we examined the influence that data scaling had on accuracy of natural neighbor predictions of depth, flow, and benthic substrate. To achieve this goal, we measured two streams at gridded resolution of 0.33 × 0.33 meter cell size over a combined area of 934 m2 to create a baseline for natural neighbor interpolated maps at 12 incremental scales ranging from a raster cell size of 0.11 m2 to 16 m2 . Analysis of predictive maps showed a logarithmic linear decay pattern in RMSE values in interpolation accuracy for variables as resolution of data used to interpolate study areas became coarser. Proportional accuracy of interpolated models (r2 ) decreased, but it was maintained up to 78% as interpolation scale moved from 0.11 m2 to 16 m2 . Results indicated that accuracy retention was suitable for assessment and management purposes at various scales different from the data collection scale. Our study is relevant to spatial modeling, fish habitat assessment, and stream habitat management because it highlights the potential of using a single dataset to fulfill analysis needs rather than investing considerable cost to develop several scaled datasets.

  6. Accuracy of different impression materials in parallel and nonparallel implants

    PubMed Central

    Vojdani, Mahroo; Torabi, Kianoosh; Ansarifard, Elham

    2015-01-01

    Background: A precise impression is mandatory to obtain passive fit in implant-supported prostheses. The aim of this study was to compare the accuracy of three impression materials in both parallel and nonparallel implant positions. Materials and Methods: In this experimental study, two partial dentate maxillary acrylic models with four implant analogues in canines and lateral incisors areas were used. One model was simulating the parallel condition and the other nonparallel one, in which implants were tilted 30° bucally and 20° in either mesial or distal directions. Thirty stone casts were made from each model using polyether (Impregum), additional silicone (Monopren) and vinyl siloxanether (Identium), with open tray technique. The distortion values in three-dimensions (X, Y and Z-axis) were measured by coordinate measuring machine. Two-way analysis of variance (ANOVA), one-way ANOVA and Tukey tests were used for data analysis (α = 0.05). Results: Under parallel condition, all the materials showed comparable, accurate casts (P = 0.74). In the presence of angulated implants, while Monopren showed more accurate results compared to Impregum (P = 0.01), Identium yielded almost similar results to those produced by Impregum (P = 0.27) and Monopren (P = 0.26). Conclusion: Within the limitations of this study, in parallel conditions, the type of impression material cannot affect the accuracy of the implant impressions; however, in nonparallel conditions, polyvinyl siloxane is shown to be a better choice, followed by vinyl siloxanether and polyether respectively. PMID:26288620

  7. Improving Estimation Accuracy of Aggregate Queries on Data Cubes

    SciTech Connect

    Pourabbas, Elaheh; Shoshani, Arie

    2008-08-15

    In this paper, we investigate the problem of estimation of a target database from summary databases derived from a base data cube. We show that such estimates can be derived by choosing a primary database which uses a proxy database to estimate the results. This technique is common in statistics, but an important issue we are addressing is the accuracy of these estimates. Specifically, given multiple primary and multiple proxy databases, that share the same summary measure, the problem is how to select the primary and proxy databases that will generate the most accurate target database estimation possible. We propose an algorithmic approach for determining the steps to select or compute the source databases from multiple summary databases, which makes use of the principles of information entropy. We show that the source databases with the largest number of cells in common provide the more accurate estimates. We prove that this is consistent with maximizing the entropy. We provide some experimental results on the accuracy of the target database estimation in order to verify our results.

  8. Setup Accuracy of the Novalis ExacTrac 6DOF System for Frameless Radiosurgery

    SciTech Connect

    Gevaert, Thierry; Verellen, Dirk; Tournel, Koen; Linthout, Nadine; Bral, Samuel; Engels, Benedikt; Collen, Christine; Depuydt, Tom; Duchateau, Michael; Reynders, Truus; Storme, Guy; De Ridder, Mark

    2012-04-01

    Purpose: Stereotactic radiosurgery using frame-based positioning is a well-established technique for the treatment of benign and malignant lesions. By contrast, a new trend toward frameless systems using image-guided positioning techniques is gaining mainstream acceptance. This study was designed to measure the detection and positioning accuracy of the ExacTrac/Novalis Body (ET/NB) for rotations and to compare the accuracy of the frameless with the frame-based radiosurgery technique. Methods and Materials: A program was developed in house to rotate reference computed tomography images. The angles measured by the system were compared with the known rotations. The accuracy of ET/NB was evaluated with a head phantom with seven lead beads inserted, mounted on a treatment couch equipped with a robotic tilt module, and was measured with a digital water level and portal films. Multiple hidden target tests (HTT) were performed to measure the overall accuracy of the different positioning techniques for radiosurgery (i.e., frameless and frame-based with relocatable mask or invasive ring, respectively). Results: The ET/NB system can detect rotational setup errors with an average accuracy of 0.09 Degree-Sign (standard deviation [SD] 0.06 Degree-Sign ), 0.02 Degree-Sign (SD 0.07 Degree-Sign ), and 0.06 Degree-Sign (SD 0.14 Degree-Sign ) for longitudinal, lateral, and vertical rotations, respectively. The average positioning accuracy was 0.06 Degree-Sign (SD 0.04 Degree-Sign ), 0.08 Degree-Sign (SD 0.06 Degree-Sign ), and 0.08 Degree-Sign (SD 0.07 Degree-Sign ) for longitudinal, lateral and vertical rotations, respectively. The results of the HTT showed an overall three-dimensional accuracy of 0.76 mm (SD 0.46 mm) for the frameless technique, 0.87 mm (SD 0.44 mm) for the relocatable mask, and 1.19 mm (SD 0.45 mm) for the frame-based technique. Conclusions: The study showed high detection accuracy and a subdegree positioning accuracy. On the basis of phantom studies, the

  9. Improvement of Accuracy in Environmental Dosimetry by TLD Cards Using Three-dimensional Calibration Method

    PubMed Central

    HosseiniAliabadi, S. J.; Hosseini Pooya, S. M.; Afarideh, H.; Mianji, F.

    2015-01-01

    Introduction The angular dependency of response for TLD cards may cause deviation from its true value on the results of environmental dosimetry, since TLDs may be exposed to radiation at different angles of incidence from the surrounding area. Objective A 3D setting of TLD cards has been calibrated isotropically in a standard radiation field to evaluate the improvement of the accuracy of measurement for environmental dosimetry. Method Three personal TLD cards were rectangularly placed in a cylindrical holder, and calibrated using 1D and 3D calibration methods. Then, the dosimeter has been used simultaneously with a reference instrument in a real radiation field measuring the accumulated dose within a time interval. Result The results show that the accuracy of measurement has been improved by 6.5% using 3D calibration factor in comparison with that of normal 1D calibration method. Conclusion This system can be utilized in large scale environmental monitoring with a higher accuracy. PMID:26157729

  10. Wind measurement accuracy for the NASA scatterometer

    NASA Astrophysics Data System (ADS)

    Long, David G.; Oliphant, Travis

    1997-09-01

    The NASA Scatterometer (NSCAT) is designed to make measurements of the normalized radar backscatter coefficient ((sigma) o) of the ocean's surface. The measured (sigma) o is a function of the viewing geometry and the surface roughness due to wind-generated waves. By making multiple measurements of the same location from different azimuth angles it is possible to retrieve the near-surface wind speed and direction with the aid of a Geophysical Model Function (GMF) which relates wind and (sigma) o. The wind is estimated from the noisy (sigma) o measurements using maximum likelihood techniques. The probability density of the measured (sigma) o is assumed to be Gaussian with a variance that depends on the true (sigma) o and therefore the wind through the GMF and the measurements from different azimuth angles are assumed independent in estimating the wind. In order to estimate the accuracy of the retrieved wind, we derive the Cramer-Reo (CR) bound for wind estimation from scatterometer measurements. We show that the CR bound can be used as an error bar on the estimated wind. The role of geophysical modeling error in the GMF is considered and shown to play a significant role in the wind accuracy. Estimates of the accuracy of NSCAT measurements are given along with other scatterometer geometries and types.

  11. Accuracy control in Monte Carlo radiative calculations

    NASA Technical Reports Server (NTRS)

    Almazan, P. Planas

    1993-01-01

    The general accuracy law that rules the Monte Carlo, ray-tracing algorithms used commonly for the calculation of the radiative entities in the thermal analysis of spacecraft are presented. These entities involve transfer of radiative energy either from a single source to a target (e.g., the configuration factors). or from several sources to a target (e.g., the absorbed heat fluxes). In fact, the former is just a particular case of the latter. The accuracy model is later applied to the calculation of some specific radiative entities. Furthermore, some issues related to the implementation of such a model in a software tool are discussed. Although only the relative error is considered through the discussion, similar results can be derived for the absolute error.

  12. Geographic stacking: Decision fusion to increase global land cover map accuracy

    NASA Astrophysics Data System (ADS)

    Clinton, Nicholas; Yu, Le; Gong, Peng

    2015-05-01

    Techniques to combine multiple classifier outputs is an established sub-discipline in data mining, referred to as "stacking," "ensemble classification," or "meta-learning." Here we describe how stacking of geographically allocated classifications can create a map composite of higher accuracy than any of the individual classifiers. We used both voting algorithms and trainable classifiers with a set of validation data to combine individual land cover maps. We describe the generality of this setup in terms of existing algorithms and accuracy assessment procedures. This method has the advantage of not requiring posterior probabilities or level of support for predicted class labels. We demonstrate the technique using Landsat based, 30-meter land cover maps, the highest resolution, globally available product of this kind. We used globally distributed validation samples to composite the maps and compute accuracy. We show that geographic stacking can improve individual map accuracy by up to 6.6%. The voting methods can also achieve higher accuracy than the best of the input classifications. Accuracies from different classifiers, input data, and output type are compared. The results are illustrated on a Landsat scene in California, USA. The compositing technique described here has broad applicability in remote sensing based map production and geographic classification.

  13. Spatial and temporal analysis on the distribution of active radio-frequency identification (RFID) tracking accuracy with the Kriging method.

    PubMed

    Liu, Xin; Shannon, Jeremy; Voun, Howard; Truijens, Martijn; Chi, Hung-Lin; Wang, Xiangyu

    2014-10-29

    Radio frequency identification (RFID) technology has already been applied in a number of areas to facilitate the tracking process. However, the insufficient tracking accuracy of RFID is one of the problems that impedes its wider application. Previous studies focus on examining the accuracy of discrete points RFID, thereby leaving the tracking accuracy of the areas between the observed points unpredictable. In this study, spatial and temporal analysis is applied to interpolate the continuous distribution of RFID tracking accuracy based on the Kriging method. An implementation trial has been conducted in the loading and docking area in front of a warehouse to validate this approach. The results show that the weak signal area can be easily identified by the approach developed in the study. The optimum distance between two RFID readers and the effect of the sudden removal of readers are also presented by analysing the spatial and temporal variation of RFID tracking accuracy. This study reveals the correlation between the testing time and the stability of RFID tracking accuracy. Experimental results show that the proposed approach can be used to assist the RFID system setup process to increase tracking accuracy.

  14. Spatial and Temporal Analysis on the Distribution of Active Radio-Frequency Identification (RFID) Tracking Accuracy with the Kriging Method

    PubMed Central

    Liu, Xin; Shannon, Jeremy; Voun, Howard; Truijens, Martijn; Chi, Hung-Lin; Wang, Xiangyu

    2014-01-01

    Radio frequency identification (RFID) technology has already been applied in a number of areas to facilitate the tracking process. However, the insufficient tracking accuracy of RFID is one of the problems that impedes its wider application. Previous studies focus on examining the accuracy of discrete points RFID, thereby leaving the tracking accuracy of the areas between the observed points unpredictable. In this study, spatial and temporal analysis is applied to interpolate the continuous distribution of RFID tracking accuracy based on the Kriging method. An implementation trial has been conducted in the loading and docking area in front of a warehouse to validate this approach. The results show that the weak signal area can be easily identified by the approach developed in the study. The optimum distance between two RFID readers and the effect of the sudden removal of readers are also presented by analysing the spatial and temporal variation of RFID tracking accuracy. This study reveals the correlation between the testing time and the stability of RFID tracking accuracy. Experimental results show that the proposed approach can be used to assist the RFID system setup process to increase tracking accuracy. PMID:25356648

  15. Accuracy of Reduced and Extended Thin-Wire Kernels

    SciTech Connect

    Burke, G J

    2008-11-24

    Some results are presented comparing the accuracy of the reduced thin-wire kernel and an extended kernel with exact integration of the 1/R term of the Green's function and results are shown for simple wire structures.

  16. Assessment of the Thematic Accuracy of Land Cover Maps

    NASA Astrophysics Data System (ADS)

    Höhle, J.

    2015-08-01

    Several land cover maps are generated from aerial imagery and assessed by different approaches. The test site is an urban area in Europe for which six classes (`building', `hedge and bush', `grass', `road and parking lot', `tree', `wall and car port') had to be derived. Two classification methods were applied (`Decision Tree' and `Support Vector Machine') using only two attributes (height above ground and normalized difference vegetation index) which both are derived from the images. The assessment of the thematic accuracy applied a stratified design and was based on accuracy measures such as user's and producer's accuracy, and kappa coefficient. In addition, confidence intervals were computed for several accuracy measures. The achieved accuracies and confidence intervals are thoroughly analysed and recommendations are derived from the gained experiences. Reliable reference values are obtained using stereovision, false-colour image pairs, and positioning to the checkpoints with 3D coordinates. The influence of the training areas on the results is studied. Cross validation has been tested with a few reference points in order to derive approximate accuracy measures. The two classification methods perform equally for five classes. Trees are classified with a much better accuracy and a smaller confidence interval by means of the decision tree method. Buildings are classified by both methods with an accuracy of 99% (95% CI: 95%-100%) using independent 3D checkpoints. The average width of the confidence interval of six classes was 14% of the user's accuracy.

  17. Increase in error threshold for quasispecies by heterogeneous replication accuracy

    NASA Astrophysics Data System (ADS)

    Aoki, Kazuhiro; Furusawa, Mitsuru

    2003-09-01

    In this paper we investigate the error threshold for quasispecies with heterogeneous replication accuracy. We show that the coexistence of error-free and error-prone polymerases can greatly increase the error threshold without a catastrophic loss of genetic information. We also show that the error threshold is influenced by the number of replicores. Our research suggests that quasispecies with heterogeneous replication accuracy can reduce the genetic cost of selective evolution while still producing a variety of mutants.

  18. The effect of atmospheric and topographic correction methods on land cover classification accuracy

    NASA Astrophysics Data System (ADS)

    Vanonckelen, Steven; Lhermitte, Stefaan; Van Rompaey, Anton

    2013-10-01

    Mapping of vegetation in mountain areas based on remote sensing is obstructed by atmospheric and topographic distortions. A variety of atmospheric and topographic correction methods has been proposed to minimize atmospheric and topographic effects and should in principle lead to a better land cover classification. Only a limited number of atmospheric and topographic combinations has been tested and the effect on class accuracy and on different illumination conditions is not yet researched extensively. The purpose of this study was to evaluate the effect of coupled correction methods on land cover classification accuracy. Therefore, all combinations of three atmospheric (no atmospheric correction, dark object subtraction and correction based on transmittance functions) and five topographic corrections (no topographic correction, band ratioing, cosine correction, pixel-based Minnaert and pixel-based C-correction) were applied on two acquisitions (2009 and 2010) of a Landsat image in the Romanian Carpathian mountains. The accuracies of the fifteen resulting land cover maps were evaluated statistically based on two validation sets: a random validation set and a validation subset containing pixels present in the difference area between the uncorrected classification and one of the fourteen corrected classifications. New insights into the differences in classification accuracy were obtained. First, results showed that all corrected images resulted in higher overall classification accuracies than the uncorrected images. The highest accuracy for the full validation set was achieved after combination of an atmospheric correction based on transmittance functions and a pixel-based Minnaert topographic correction. Secondly, class accuracies of especially the coniferous and mixed forest classes were enhanced after correction. There was only a minor improvement for the other land cover classes (broadleaved forest, bare soil, grass and water). This was explained by the position

  19. The limitations of wind measurement accuracy for balloon systems

    NASA Technical Reports Server (NTRS)

    Luers, J. K.; Macarthur, C. D.

    1974-01-01

    The error in horizontal wind field measurements as computed from the trajectory of balloons with linear and quadratic rise rates (as functions of altitude) has been derived. Balloon trajectories through light, moderate, and severe wind fields have been considered. Figures are presented which show the wind error vs altitude for various rise rates in each wind field, assuming linear smoothing of the trajectory data. The rise rate profile of the Jimsphere is analyzed as a special case. The results and figures presented are useful in determining the ultimate capability of rising balloon systems in general and for the Jimsphere system in particular for measuring wind from the surface to 18 km. Using the figures presented, it is possible to estimate the wind accuracy that can be achieved by any type of rising balloon by knowing only its rise rate behavior vs altitude. In addition, the results can be used in balloon design to determine what rise rate function is needed to achieve specified wind accuracies. A table is presented which shows the balloon radius for smooth and roughened spheres needed to achieve 2 to 20 m/sec rise rates at 10 and 14 km altitudes.

  20. Measuring Diagnoses: ICD Code Accuracy

    PubMed Central

    O'Malley, Kimberly J; Cook, Karon F; Price, Matt D; Wildes, Kimberly Raiford; Hurdle, John F; Ashton, Carol M

    2005-01-01

    Objective To examine potential sources of errors at each step of the described inpatient International Classification of Diseases (ICD) coding process. Data Sources/Study Setting The use of disease codes from the ICD has expanded from classifying morbidity and mortality information for statistical purposes to diverse sets of applications in research, health care policy, and health care finance. By describing a brief history of ICD coding, detailing the process for assigning codes, identifying where errors can be introduced into the process, and reviewing methods for examining code accuracy, we help code users more systematically evaluate code accuracy for their particular applications. Study Design/Methods We summarize the inpatient ICD diagnostic coding process from patient admission to diagnostic code assignment. We examine potential sources of errors at each step and offer code users a tool for systematically evaluating code accuracy. Principle Findings Main error sources along the “patient trajectory” include amount and quality of information at admission, communication among patients and providers, the clinician's knowledge and experience with the illness, and the clinician's attention to detail. Main error sources along the “paper trail” include variance in the electronic and written records, coder training and experience, facility quality-control efforts, and unintentional and intentional coder errors, such as misspecification, unbundling, and upcoding. Conclusions By clearly specifying the code assignment process and heightening their awareness of potential error sources, code users can better evaluate the applicability and limitations of codes for their particular situations. ICD codes can then be used in the most appropriate ways. PMID:16178999

  1. Accuracy testing of electric groundwater-level measurement tapes

    USGS Publications Warehouse

    Jelinski, Jim; Clayton, Christopher S.; Fulford, Janice M.

    2015-01-01

    The accuracy tests demonstrated that none of the electric-tape models tested consistently met the suggested USGS accuracy of ±0.01 ft. The test data show that the tape models in the study should give a water-level measurement that is accurate to roughly ±0.05 ft per 100 ft without additional calibration. To meet USGS accuracy guidelines, the electric-tape models tested will need to be individually calibrated. Specific conductance also plays a part in tape accuracy. The probes will not work in water with specific conductance values near zero, and the accuracy of one probe was unreliable in very high conductivity water (10,000 microsiemens per centimeter).

  2. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

    Kronenwetter, Jeffrey; Carter, Delano R.; Todirita, Monica; Chu, Donald

    2016-01-01

    The GOES-R magnetometer accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. To achieve this, the sensor itself has better than 1 nT accuracy. Because zero offset and scale factor drift over time, it is also necessary to perform annual calibration maneuvers. To predict performance, we used covariance analysis and attempted to corroborate it with simulations. Although not perfect, the two generally agree and show the expected behaviors. With the annual calibration regimen, these predictions suggest that the magnetometers will meet their accuracy requirements.

  3. Estimated Accuracy of Three Common Trajectory Statistical Methods

    NASA Technical Reports Server (NTRS)

    Kabashnikov, Vitaliy P.; Chaikovsky, Anatoli P.; Kucsera, Tom L.; Metelskaya, Natalia S.

    2011-01-01

    Three well-known trajectory statistical methods (TSMs), namely concentration field (CF), concentration weighted trajectory (CWT), and potential source contribution function (PSCF) methods were tested using known sources and artificially generated data sets to determine the ability of TSMs to reproduce spatial distribution of the sources. In the works by other authors, the accuracy of the trajectory statistical methods was estimated for particular species and at specified receptor locations. We have obtained a more general statistical estimation of the accuracy of source reconstruction and have found optimum conditions to reconstruct source distributions of atmospheric trace substances. Only virtual pollutants of the primary type were considered. In real world experiments, TSMs are intended for application to a priori unknown sources. Therefore, the accuracy of TSMs has to be tested with all possible spatial distributions of sources. An ensemble of geographical distributions of virtual sources was generated. Spearman s rank order correlation coefficient between spatial distributions of the known virtual and the reconstructed sources was taken to be a quantitative measure of the accuracy. Statistical estimates of the mean correlation coefficient and a range of the most probable values of correlation coefficients were obtained. All the TSMs that were considered here showed similar close results. The maximum of the ratio of the mean correlation to the width of the correlation interval containing the most probable correlation values determines the optimum conditions for reconstruction. An optimal geographical domain roughly coincides with the area supplying most of the substance to the receptor. The optimal domain s size is dependent on the substance decay time. Under optimum reconstruction conditions, the mean correlation coefficients can reach 0.70 0.75. The boundaries of the interval with the most probable correlation values are 0.6 0.9 for the decay time of 240 h

  4. Improving metacomprehension accuracy in an undergraduate course context.

    PubMed

    Wiley, Jennifer; Griffin, Thomas D; Jaeger, Allison J; Jarosz, Andrew F; Cushen, Patrick J; Thiede, Keith W

    2016-12-01

    Students tend to have poor metacomprehension when learning from text, meaning they are not able to distinguish between what they have understood well and what they have not. Although there are a good number of studies that have explored comprehension monitoring accuracy in laboratory experiments, fewer studies have explored this in authentic course contexts. This study investigated the effect of an instructional condition that encouraged comprehension-test-expectancy and self-explanation during study on metacomprehension accuracy in the context of an undergraduate course in research methods. Results indicated that when students received this instructional condition, relative metacomprehension accuracy was better than in a comparison condition. In addition, differences were also seen in absolute metacomprehension accuracy measures, strategic study behaviors, and learning outcomes. The results of the current study demonstrate that a condition that has improved relative metacomprehension accuracy in laboratory contexts may have value in real classroom contexts as well. (PsycINFO Database Record

  5. Hey Teacher, Your Personality's Showing!

    ERIC Educational Resources Information Center

    Paulsen, James R.

    1977-01-01

    A study of 30 fourth, fifth, and sixth grade teachers and 300 of their students showed that a teacher's age, sex, and years of experience did not relate to students' mathematics achievement, but that more effective teachers showed greater "freedom from defensive behavior" than did less effective teachers. (DT)

  6. Planning a Successful Tech Show

    ERIC Educational Resources Information Center

    Nikirk, Martin

    2011-01-01

    Tech shows are a great way to introduce prospective students, parents, and local business and industry to a technology and engineering or career and technical education program. In addition to showcasing instructional programs, a tech show allows students to demonstrate their professionalism and skills, practice public presentations, and interact…

  7. High-accuracy indoor positioning system based on visible light communication

    NASA Astrophysics Data System (ADS)

    Wei, Ling; Zhang, Hongming; Yu, Bingyan; Guan, Yang

    2015-11-01

    A visible light communication (VLC)-based high-accuracy indoor positioning system is proposed and demonstrated. In this system, the light-emitting diode identification (LED-ID) indicating the position information of the LED can be transmitted to the receiver by the illumination LED through VLC. In the meantime, with the aid of a camera and angular sensors of the mobile device, a coordinate transform can be employed to calculate the relative position between the receiver and the reference LED so that the position of the receiver can be determined. Finally, the experimental results show that 2-cm positioning accuracy can be achieved and the simulation results indicate that the positioning error can be limited within 4.7 cm when the accuracy of angular sensors is 1 deg.

  8. Accuracy of RNA-Seq and its dependence on sequencing depth

    PubMed Central

    2012-01-01

    Background The cost of DNA sequencing has undergone a dramatical reduction in the past decade. As a result, sequencing technologies have been increasingly applied to genomic research. RNA-Seq is becoming a common technique for surveying gene expression based on DNA sequencing. As it is not clear how increased sequencing capacity has affected measurement accuracy of mRNA, we sought to investigate that relationship. Result We empirically evaluate the accuracy of repeated gene expression measurements using RNA-Seq. We identify library preparation steps prior to DNA sequencing as the main source of error in this process. Studying three datasets, we show that the accuracy indeed improves with the sequencing depth. However, the rate of improvement as a function of sequence reads is generally slower than predicted by the binomial distribution. We therefore used the beta-binomial distribution to model the overdispersion. The overdispersion parameters we introduced depend explicitly on the number of reads so that the resulting statistical uncertainty is consistent with the empirical data that measurement accuracy increases with the sequencing depth. The overdispersion parameters were determined by maximizing the likelihood. We shown that our modified beta-binomial model had lower false discovery rate than the binomial or the pure beta-binomial models. Conclusion We proposed a novel form of overdispersion guaranteeing that the accuracy improves with sequencing depth. We demonstrated that the new form provides a better fit to the data. PMID:23320920

  9. Size effect on the polygon-based estimation of user's, producer's and overall accuracies

    NASA Astrophysics Data System (ADS)

    Radoux, J.; Bogaert, P.

    2012-04-01

    Geographic object-based image analysis is a processing method where groups of spatially adjacent pixels are classified as elementary units. This approach raises concerns about the design of subsequent validation strategies. Thought it has been suggested that polygon sampling units should be used in validation schemes when the map is partitioned in polygons, little attention has been paid on the consequences of this choice. Contrary to the point-based sampling, polygon indeed have different spatial extents that should be used for the estimation of the primary (overall, user's and producer's) thematic accuracy indices. In this paper, the quantitative effects related to the variable size of the sampling units on the estimation primary accuracy indices are addressed. An object-based sampling strategy is proposed and compared with other approaches used in the literature for the thematic accuracy assessment of object-based classifications. The new sampling scheme and sample analysis are founded on a sound theoretical framework based on few working hypotheses. The performance of the sampling strategies is quantified using object-based classifications results simulated for a Quickbird imagery. The different effects of the polygon size on the efficiency of the validation method are assessed. The bias and the variance of the primary accuracy estimates were used as indicators of the methods benefits. The results show that the proposed method is the most efficient for overall accuracy estimates but not systematically better than point-based sampling for user and producer accuracy. The effect of the size distribution, characterized by the coefficient of variation, is to increase the variance of the object-based predictors. In addition, the correlation between the size and the classification accuracy may lead to systematic errors if not properly taken into account. The results therefore suggest that the effect of the size on the estimation of primary parameters should not be

  10. Satellite Animation Shows California Storms

    NASA Video Gallery

    This animation of visible and infrared imagery from NOAA's GOES-West satellite shows a series of moisture-laden storms affecting California from Jan. 6 through Jan. 9, 2017. TRT: 00:36 Credit: NASA...

  11. Satellite Movie Shows Erika Dissipate

    NASA Video Gallery

    This animation of visible and infrared imagery from NOAA's GOES-West satellite from Aug. 27 to 29 shows Tropical Storm Erika move through the Eastern Caribbean Sea and dissipate near eastern Cuba. ...

  12. Comparison of Dimensional Accuracies Using Two Elastomeric Impression Materials in Casting Three-dimensional Tool Marks.

    PubMed

    Wang, Zhen

    2016-05-01

    The purpose of this study was to evaluate two types of impression materials which were frequently used for casting three-dimensional tool marks in China, namely (i) dental impression material and (ii) special elastomeric impression material for tool mark casting. The two different elastomeric impression materials were compared under equal conditions. The parameters measured were dimensional accuracies, the number of air bubbles, the ease of use, and the sharpness and quality of the individual characteristics present on casts. The results showed that dental impression material had the advantage of special elastomeric impression material in casting tool marks in crime scenes; hence, it combined ease of use, dimensional accuracy, sharpness and high quality.

  13. The effect of spatial, spectral and radiometric factors on classification accuracy using thematic mapper data

    NASA Technical Reports Server (NTRS)

    Wrigley, R. C.; Acevedo, W.; Alexander, D.; Buis, J.; Card, D.

    1984-01-01

    An experiment of a factorial design was conducted to test the effects on classification accuracy of land cover types due to the improved spatial, spectral and radiometric characteristics of the Thematic Mapper (TM) in comparison to the Multispectral Scanner (MSS). High altitude aircraft scanner data from the Airborne Thematic Mapper instrument was acquired over central California in August, 1983 and used to simulate Thematic Mapper data as well as all combinations of the three characteristics for eight data sets in all. Results for the training sites (field center pixels) showed better classification accuracies for MSS spatial resolution, TM spectral bands and TM radiometry in order of importance.

  14. Note: Periodic error measurement in heterodyne interferometers using a subpicometer accuracy Fabry-Perot interferometer.

    PubMed

    Zhu, Minhao; Wei, Haoyun; Wu, Xuejian; Li, Yan

    2014-08-01

    Periodic error is the major problem that limits the accuracy of heterodyne interferometry. A traceable system for periodic error measurement is developed based on a nonlinearity free Fabry-Perot (F-P) interferometer. The displacement accuracy of the F-P interferometer is 0.49 pm at 80 ms averaging time, with the measurement results referenced to an optical frequency comb. Experimental comparison between the F-P interferometer and a commercial heterodyne interferometer is carried out and it shows that the first harmonic periodic error dominates in the commercial heterodyne interferometer with an error amplitude of 4.64 nm.

  15. Accuracy and borehole influences in pulsed neutron gamma density logging while drilling.

    PubMed

    Yu, Huawei; Sun, Jianmeng; Wang, Jiaxin; Gardner, Robin P

    2011-09-01

    A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties.

  16. An insight into linear quarter car model accuracy

    NASA Astrophysics Data System (ADS)

    Maher, Damien; Young, Paul

    2011-03-01

    The linear quarter car model is the most widely used suspension system model. A number of authors expressed doubts about the accuracy of the linear quarter car model in predicting the movement of a complex nonlinear suspension system. In this investigation, a quarter car rig, designed to mimic the popular MacPherson strut suspension system, is subject to narrowband excitation at a range of frequencies using a motor driven cam. Linear and nonlinear quarter car simulations of the rig are developed. Both isolated and operational testing techniques are used to characterise the individual suspension system components. Simulations carried out using the linear and nonlinear models are compared to measured data from the suspension test rig at selected excitation frequencies. Results show that the linear quarter car model provides a reasonable approximation of unsprung mass acceleration but significantly overpredicts sprung mass acceleration magnitude. The nonlinear simulation, featuring a trilinear shock absorber model and nonlinear tyre, produces results which are significantly more accurate than linear simulation results. The effect of tyre damping on the nonlinear model is also investigated for narrowband excitation. It is found to reduce the magnitude of unsprung mass acceleration peaks and contribute to an overall improvement in simulation accuracy.

  17. Accuracy of the correlation method of the thermal neutron absorption cross-section determination for rocks

    NASA Astrophysics Data System (ADS)

    Krynicka, Ewa

    1995-08-01

    The influence of various random errors on the accuracy of thermal neutron absorption cross-sections determined by a correlation method is discussed. It is considered either as an absolute accuracy, when all experimental errors arc taken into account, or as an experimental assay accuracy, when the reference moderator parameters are assumed as the invariant data fixed for all experiments. The estimated accuracy is compared with the accuracy of results obtained for the same rock sample by Czubek's measurement method.

  18. Accuracy of Pressure Sensitive Paint

    NASA Technical Reports Server (NTRS)

    Liu, Tianshu; Guille, M.; Sullivan, J. P.

    2001-01-01

    Uncertainty in pressure sensitive paint (PSP) measurement is investigated from a standpoint of system modeling. A functional relation between the imaging system output and luminescent emission from PSP is obtained based on studies of radiative energy transports in PSP and photodetector response to luminescence. This relation provides insights into physical origins of various elemental error sources and allows estimate of the total PSP measurement uncertainty contributed by the elemental errors. The elemental errors and their sensitivity coefficients in the error propagation equation are evaluated. Useful formulas are given for the minimum pressure uncertainty that PSP can possibly achieve and the upper bounds of the elemental errors to meet required pressure accuracy. An instructive example of a Joukowsky airfoil in subsonic flows is given to illustrate uncertainty estimates in PSP measurements.

  19. Linearity and accuracy of ultraviolet and visible wavelength photometer: an interlaboratory survey.

    PubMed

    Vanderlinde, R E; Richards, A H; Kowalski, P

    1975-05-15

    A survey was made to determine the linearity and accuracy of ultraviolet and visible wavelength photometers used by laboratories in New York State. Two solutions each of high-purity potassium dichromate and cobalt ammonium sulfate were submitted for photometric performance studies. The majority of the participant spectrophotometer results showed good correlation with reference data. Broad half-band width (greater than 10 nm) photometers showed little deviation from linearity. Coefficients of variation for the models surveyed were 5-10%.

  20. Phyllodes tumor showing intraductal growth.

    PubMed

    Makidono, Akari; Tsunoda, Hiroko; Mori, Miki; Yagata, Hiroshi; Onoda, Yui; Kikuchi, Mari; Nozaki, Taiki; Saida, Yukihisa; Nakamura, Seigo; Suzuki, Koyu

    2013-07-01

    Phyllodes tumor of the breast is a rare fibroepithelial lesion and particularly uncommon in adolescent girls. It is thought to arise from the periductal rather than intralobular stroma. Usually, it is seen as a well-defined mass. Phyllodes tumor showing intraductal growth is extremely rare. Here we report a girl who has a phyllodes tumor with intraductal growth.

  1. Study on High Accuracy Topographic Mapping via UAV-based Images

    NASA Astrophysics Data System (ADS)

    Chi, Yun-Yao; Lee, Ya-Fen; Tsai, Shang-En

    2016-10-01

    Unmanned aerial vehicle (UAV) provides a promising tool for the acquisition of such multi-temporal aerial stereo photos and high-resolution digital surface models. Recently, the flight of UAVs operates with high degrees of autonomy by the global position system and onboard digit camera and computer. The UAV-based mapping can be obtained faster and cheaper, but its accuracy is anxious. This paper aims to identify the integration ability of high accuracy topographic map via the image of quad-rotors UAV and ground control points (GCPs). The living survey data is collected in the Errn river basins area in Tainan, Taiwan. The high accuracy UAV-based topographic in the study area is calibrated by the local coordinate of GCPs using the total station with the accuracy less than 1/2000. The comparison results show the accuracy of UAV-based topographic is accepted by overlapping. The results can be a reference for the practice works of mapping survey in earth.

  2. High accuracy radiation efficiency measurement techniques

    NASA Technical Reports Server (NTRS)

    Kozakoff, D. J.; Schuchardt, J. M.

    1981-01-01

    The relatively large antenna subarrays (tens of meters) to be used in the Solar Power Satellite, and the desire to accurately quantify antenna performance, dictate the requirement for specialized measurement techniques. The error contributors associated with both far-field and near-field antenna measurement concepts were quantified. As a result, instrumentation configurations with measurement accuracy potential were identified. In every case, advances in the state of the art of associated electronics were found to be required. Relative cost trade-offs between a candidate far-field elevated antenna range and near-field facility were also performed.

  3. Magic Carpet Shows Its Colors

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The upper left image in this display is from the panoramic camera on the Mars Exploration Rover Spirit, showing the 'Magic Carpet' region near the rover at Gusev Crater, Mars, on Sol 7, the seventh martian day of its journey (Jan. 10, 2004). The lower image, also from the panoramic camera, is a monochrome (single filter) image of a rock in the 'Magic Carpet' area. Note that colored portions of the rock correlate with extracted spectra shown in the plot to the side. Four different types of materials are shown: the rock itself, the soil in front of the rock, some brighter soil on top of the rock, and some dust that has collected in small recesses on the rock face ('spots'). Each color on the spectra matches a line on the graph, showing how the panoramic camera's different colored filters are used to broadly assess the varying mineral compositions of martian rocks and soils.

  4. On the Accuracy Potential in Underwater/Multimedia Photogrammetry.

    PubMed

    Maas, Hans-Gerd

    2015-07-24

    Underwater applications of photogrammetric measurement techniques usually need to deal with multimedia photogrammetry aspects, which are characterized by the necessity of handling optical rays that are refracted at interfaces between optical media with different refractive indices according to Snell's Law. This so-called multimedia geometry has to be incorporated into geometric models in order to achieve correct measurement results. The paper shows a flexible yet strict geometric model for the handling of refraction effects on the optical path, which can be implemented as a module into photogrammetric standard tools such as spatial resection, spatial intersection, bundle adjustment or epipolar line computation. The module is especially well suited for applications, where an object in water is observed by cameras in air through one or more planar glass interfaces, as it allows for some simplifications here. In the second part of the paper, several aspects, which are relevant for an assessment of the accuracy potential in underwater/multimedia photogrammetry, are discussed. These aspects include network geometry and interface planarity issues as well as effects caused by refractive index variations and dispersion and diffusion under water. All these factors contribute to a rather significant degradation of the geometric accuracy potential in underwater/multimedia photogrammetry. In practical experiments, a degradation of the quality of results by a factor two could be determined under relatively favorable conditions.

  5. Accuracy of an estuarine hydrodynamic model using smooth elements

    USGS Publications Warehouse

    Walters, Roy A.; Cheng, Ralph T.

    1980-01-01

    A finite element model which uses triangular, isoparametric elements with quadratic basis functions for the two velocity components and linear basis functions for water surface elevation is used in the computation of shallow water wave motions. Specifically addressed are two common uncertainties in this class of two-dimensional hydrodynamic models: the treatment of the boundary conditions at open boundaries and the treatment of lateral boundary conditions. The accuracy of the models is tested with a set of numerical experiments in rectangular and curvilinear channels with constant and variable depth. The results indicate that errors in velocity at the open boundary can be significant when boundary conditions for water surface elevation are specified. Methods are suggested for minimizing these errors. The results also show that continuity is better maintained within the spatial domain of interest when ‘smooth’ curve-sided elements are used at shoreline boundaries than when piecewise linear boundaries are used. Finally, a method for network development is described which is based upon a continuity criterion to gauge accuracy. A finite element network for San Francisco Bay, California, is used as an example.

  6. Key Technical Aspects Influencing the Accuracy of Tablet Subdivision.

    PubMed

    Teixeira, Maíra T; Sá-Barreto, Lívia C L; Gratieri, Taís; Gelfuso, Guilherme M; Silva, Izabel C R; Cunha-Filho, Marcílio S S

    2016-09-01

    Tablet subdivision is a common practice used mainly for dose adjustment. The aim of this study was to investigate how the technical aspects of production as well as the method of tablets subdivision (employing a tablet splitter or a kitchen knife) influence the accuracy of this practice. Five drugs commonly used as subdivided tablets were selected. For each drug, the innovator drug product, a scored-generic and a non-scored generic were investigated totalizing fifteen drug products. Mechanical and physical tests, including image analysis, were performed. Additionally, comparisons were made between tablet subdivision method, score, shape, diluent composition and coating. Image analysis based on surface area was a useful tool as an alternative assay to evaluate the accuracy of tablet subdivision. The tablet splitter demonstrates an advantage relative to a knife as it showed better results in weight loss and friability tests. Oblong, coated and scored tablets had better results after subdivision than round, uncoated and non-scored tablets. The presence of elastic diluents such as starch and dibasic phosphate dehydrate conferred a more appropriate behaviour for the subdivision process than plastic materials such as microcrystalline cellulose and lactose. Finally, differences were observed between generics and their innovator products in all selected drugs with regard the quality control assays in divided tablet, which highlights the necessity of health regulations to consider subdivision performance at least in marketing authorization of generic products.

  7. On the Accuracy Potential in Underwater/Multimedia Photogrammetry

    PubMed Central

    Maas, Hans-Gerd

    2015-01-01

    Underwater applications of photogrammetric measurement techniques usually need to deal with multimedia photogrammetry aspects, which are characterized by the necessity of handling optical rays that are refracted at interfaces between optical media with different refractive indices according to Snell’s Law. This so-called multimedia geometry has to be incorporated into geometric models in order to achieve correct measurement results. The paper shows a flexible yet strict geometric model for the handling of refraction effects on the optical path, which can be implemented as a module into photogrammetric standard tools such as spatial resection, spatial intersection, bundle adjustment or epipolar line computation. The module is especially well suited for applications, where an object in water is observed by cameras in air through one or more planar glass interfaces, as it allows for some simplifications here. In the second part of the paper, several aspects, which are relevant for an assessment of the accuracy potential in underwater/multimedia photogrammetry, are discussed. These aspects include network geometry and interface planarity issues as well as effects caused by refractive index variations and dispersion and diffusion under water. All these factors contribute to a rather significant degradation of the geometric accuracy potential in underwater/multimedia photogrammetry. In practical experiments, a degradation of the quality of results by a factor two could be determined under relatively favorable conditions. PMID:26213942

  8. Temporal accuracy of human cortico-cortical interactions

    PubMed Central

    Abeles, Moshe

    2016-01-01

    The precision in space and time of interactions among multiple cortical sites was evaluated by examining repeating precise spatiotemporal patterns of instances in which cortical currents showed brief amplitude undulations. The amplitudes of the cortical current dipoles were estimated by applying a variant of synthetic aperture magnetometry to magnetoencephalographic (MEG) recordings of subjects tapping to metric auditory rhythms of drum beats. Brief amplitude undulations were detected in the currents by template matching at a rate of 2–3 per second. Their timing was treated as point processes, and precise spatiotemporal patterns were searched for. By randomly teetering these point processes within a time window W, we estimated the accuracy of the timing of these brief amplitude undulations and compared the results with those obtained by applying the same analysis to traces composed of random numbers. The results demonstrated that the timing accuracy of patterns was better than 3 ms. Successful classification of two different cognitive processes based on these patterns suggests that at least some of the repeating patterns are specific to a cognitive process. PMID:26843604

  9. The Accuracy of Molecular Processes

    NASA Astrophysics Data System (ADS)

    Stavans, Joel

    Recombination is arguably one of the most fundamental mechanisms driving genetic diversity during evolution. Recombination takes place in one way or another from viruses such as HIV and polio, to bacteria, and finally to man. In both prokaryotes and eukaryotes, homologous recombination is assisted by enzymes, recombinases, that promote the exchange of strands between two segments of DNA, thereby creating new genetic combinations. In bacteria, homologous recombination takes place as a pathway for the repair of DNA lesions and also during horizontal or lateral gene transfer processes, in which cells take in exogenous pieces of DNA. This allows bacteria to evolve rapidly by acquiring large sequences of DNA, a process which would take too long by gene duplications and single mutations. I will survey recent results on the fidelity of homologous recombination as catalyzed by the bacterial recombinase RecA. These results show discrimination up to the level of single base mismatches, during the initial stages of the recombination process. A cascaded kinetic proofreading process is proposed to explain this high discrimination. Kinetic proofreading ideas are also reviewed.

  10. Moyamoya disease: diagnostic accuracy of MRI.

    PubMed

    Yamada, I; Suzuki, S; Matsushima, Y

    1995-07-01

    Our purpose was to evaluate the diagnostic accuracy of MRI in moyamoya disease. We studied 30 patients with this disease, comparing MRI and angiographic findings. The diagnostic value of MRI was evaluated for occlusive lesions, collateral vessels, and parenchymal lesions. In all patients bilateral occlusion or stenosis of the supraclinoid internal carotid artery and proximal anterior and middle cerebral arteries was clearly shown by MRI, and staging of the extent of occlusion agreed with angiographic staging in 44 (73%) of 60 arteries. MRI, particularly coronal images, clearly showed basal cerebral moyamoya vessels in 54 hemispheres, and 45 of a total of 71 large leptomeningeal and transdural collateral vessels were identified. MRI also showed parenchymal lesions in 48 (80%) hemispheres, and the extent of occlusion in the anterior and posterior circulations respectively correlated with white matter and cortical and/or subcortical infarcts.

  11. Accuracy and Resolution of Kinect Depth Data for Indoor Mapping Applications

    PubMed Central

    Khoshelham, Kourosh; Elberink, Sander Oude

    2012-01-01

    Consumer-grade range cameras such as the Kinect sensor have the potential to be used in mapping applications where accuracy requirements are less strict. To realize this potential insight into the geometric quality of the data acquired by the sensor is essential. In this paper we discuss the calibration of the Kinect sensor, and provide an analysis of the accuracy and resolution of its depth data. Based on a mathematical model of depth measurement from disparity a theoretical error analysis is presented, which provides an insight into the factors influencing the accuracy of the data. Experimental results show that the random error of depth measurement increases with increasing distance to the sensor, and ranges from a few millimeters up to about 4 cm at the maximum range of the sensor. The quality of the data is also found to be influenced by the low resolution of the depth measurements. PMID:22438718

  12. Analysis: The Accuracy and Efficacy of the Dexcom G4 Platinum Continuous Glucose Monitoring System.

    PubMed

    van Beers, Cornelis A J; DeVries, J H

    2015-04-27

    In this issue of Journal of Diabetes Science and Technology, Nakamura and Balo report on accuracy and efficacy of the Dexcom G4 Platinum Continuous Glucose Monitoring System. The authors demonstrate good overall performance of this real-time continuous glucose monitoring (RT-CGM) system, although accuracy data of the next generation RT-CGM system, the G4AP, is already available. Also, now that MARDs seem to move to single-digit numbers, the question comes up how low we need to go with accuracy. Results of the study also showed a reduction in time spent in hypoglycemia, although the clinical relevance should be questioned. To date, few trials have demonstrated a reduction of severe hypoglycemia. Conventional RT-CGM, without threshold suspension or closing the loop, might be insufficient in preventing severe hypoglycemia.

  13. Accuracy Based Generation of Thermodynamic Properties for Light Water in RELAP5-3D

    SciTech Connect

    Cliff B. Davis

    2010-09-01

    RELAP5-3D interpolates to obtain thermodynamic properties for use in its internal calculations. The accuracy of the interpolation was determined for the original steam tables currently used by the code. This accuracy evaluation showed that the original steam tables are generally detailed enough to allow reasonably accurate interpolations in most areas needed for typical analyses of nuclear reactors cooled by light water. However, there were some regions in which the original steam tables were judged to not provide acceptable accurate results. Revised steam tables were created that used a finer thermodynamic mesh between 4 and 21 MPa and 530 and 640 K. The revised steam tables solved most of the problems observed with the original steam tables. The accuracies of the original and revised steam tables were compared throughout the thermodynamic grid.

  14. [True color accuracy in digital forensic photography].

    PubMed

    Ramsthaler, Frank; Birngruber, Christoph G; Kröll, Ann-Katrin; Kettner, Mattias; Verhoff, Marcel A

    2016-01-01

    Forensic photographs not only need to be unaltered and authentic and capture context-relevant images, along with certain minimum requirements for image sharpness and information density, but color accuracy also plays an important role, for instance, in the assessment of injuries or taphonomic stages, or in the identification and evaluation of traces from photos. The perception of color not only varies subjectively from person to person, but as a discrete property of an image, color in digital photos is also to a considerable extent influenced by technical factors such as lighting, acquisition settings, camera, and output medium (print, monitor). For these reasons, consistent color accuracy has so far been limited in digital photography. Because images usually contain a wealth of color information, especially for complex or composite colors or shades of color, and the wavelength-dependent sensitivity to factors such as light and shadow may vary between cameras, the usefulness of issuing general recommendations for camera capture settings is limited. Our results indicate that true image colors can best and most realistically be captured with the SpyderCheckr technical calibration tool for digital cameras tested in this study. Apart from aspects such as the simplicity and quickness of the calibration procedure, a further advantage of the tool is that the results are independent of the camera used and can also be used for the color management of output devices such as monitors and printers. The SpyderCheckr color-code patches allow true colors to be captured more realistically than with a manual white balance tool or an automatic flash. We therefore recommend that the use of a color management tool should be considered for the acquisition of all images that demand high true color accuracy (in particular in the setting of injury documentation).

  15. Researches on High Accuracy Prediction Methods of Earth Orientation Parameters

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.

    2015-09-01

    The Earth rotation reflects the coupling process among the solid Earth, atmosphere, oceans, mantle, and core of the Earth on multiple spatial and temporal scales. The Earth rotation can be described by the Earth's orientation parameters, which are abbreviated as EOP (mainly including two polar motion components PM_X and PM_Y, and variation in the length of day ΔLOD). The EOP is crucial in the transformation between the terrestrial and celestial reference systems, and has important applications in many areas such as the deep space exploration, satellite precise orbit determination, and astrogeodynamics. However, the EOP products obtained by the space geodetic technologies generally delay by several days to two weeks. The growing demands for modern space navigation make high-accuracy EOP prediction be a worthy topic. This thesis is composed of the following three aspects, for the purpose of improving the EOP forecast accuracy. (1) We analyze the relation between the length of the basic data series and the EOP forecast accuracy, and compare the EOP prediction accuracy for the linear autoregressive (AR) model and the nonlinear artificial neural network (ANN) method by performing the least squares (LS) extrapolations. The results show that the high precision forecast of EOP can be realized by appropriate selection of the basic data series length according to the required time span of EOP prediction: for short-term prediction, the basic data series should be shorter, while for the long-term prediction, the series should be longer. The analysis also showed that the LS+AR model is more suitable for the short-term forecasts, while the LS+ANN model shows the advantages in the medium- and long-term forecasts. (2) We develop for the first time a new method which combines the autoregressive model and Kalman filter (AR+Kalman) in short-term EOP prediction. The equations of observation and state are established using the EOP series and the autoregressive coefficients

  16. Accuracy of endoscopic ultrasonography for diagnosing ulcerative early gastric cancers

    PubMed Central

    Park, Jin-Seok; Kim, Hyungkil; Bang, Byongwook; Kwon, Kyesook; Shin, Youngwoon

    2016-01-01

    Abstract Although endoscopic ultrasonography (EUS) is the first-choice imaging modality for predicting the invasion depth of early gastric cancer (EGC), the prediction accuracy of EUS is significantly decreased when EGC is combined with ulceration. The aim of present study was to compare the accuracy of EUS and conventional endoscopy (CE) for determining the depth of EGC. In addition, the various clinic-pathologic factors affecting the diagnostic accuracy of EUS, with a particular focus on endoscopic ulcer shapes, were evaluated. We retrospectively reviewed data from 236 consecutive patients with ulcerative EGC. All patients underwent EUS for estimating tumor invasion depth, followed by either curative surgery or endoscopic treatment. The diagnostic accuracy of EUS and CE was evaluated by comparing the final histologic result of resected specimen. The correlation between accuracy of EUS and characteristics of EGC (tumor size, histology, location in stomach, tumor invasion depth, and endoscopic ulcer shapes) was analyzed. Endoscopic ulcer shapes were classified into 3 groups: definite ulcer, superficial ulcer, and ill-defined ulcer. The overall accuracy of EUS and CE for predicting the invasion depth in ulcerative EGC was 68.6% and 55.5%, respectively. Of the 236 patients, 36 patients were classified as definite ulcers, 98 were superficial ulcers, and 102 were ill-defined ulcers, In univariate analysis, EUS accuracy was associated with invasion depth (P = 0.023), tumor size (P = 0.034), and endoscopic ulcer shapes (P = 0.001). In multivariate analysis, there is a significant association between superficial ulcer in CE and EUS accuracy (odds ratio: 2.977; 95% confidence interval: 1.255–7.064; P = 0.013). The accuracy of EUS for determining tumor invasion depth in ulcerative EGC was superior to that of CE. In addition, ulcer shape was an important factor that affected EUS accuracy. PMID:27472672

  17. Graphene Oxides Show Angiogenic Properties.

    PubMed

    Mukherjee, Sudip; Sriram, Pavithra; Barui, Ayan Kumar; Nethi, Susheel Kumar; Veeriah, Vimal; Chatterjee, Suvro; Suresh, Kattimuttathu Ittara; Patra, Chitta Ranjan

    2015-08-05

    Angiogenesis, a process resulting in the formation of new capillaries from the pre-existing vasculature plays vital role for the development of therapeutic approaches for cancer, atherosclerosis, wound healing, and cardiovascular diseases. In this report, the synthesis, characterization, and angiogenic properties of graphene oxide (GO) and reduced graphene oxide (rGO) have been demonstrated, observed through several in vitro and in vivo angiogenesis assays. The results here demonstrate that the intracellular formation of reactive oxygen species and reactive nitrogen species as well as activation of phospho-eNOS and phospho-Akt might be the plausible mechanisms for GO and rGO induced angiogenesis. The results altogether suggest the possibilities for the development of alternative angiogenic therapeutic approach for the treatment of cardiovascular related diseases where angiogenesis plays a significant role.

  18. Anatomical accuracy of brain connections derived from diffusion MRI tractography is inherently limited.

    PubMed

    Thomas, Cibu; Ye, Frank Q; Irfanoglu, M Okan; Modi, Pooja; Saleem, Kadharbatcha S; Leopold, David A; Pierpaoli, Carlo

    2014-11-18

    Tractography based on diffusion-weighted MRI (DWI) is widely used for mapping the structural connections of the human brain. Its accuracy is known to be limited by technical factors affecting in vivo data acquisition, such as noise, artifacts, and data undersampling resulting from scan time constraints. It generally is assumed that improvements in data quality and implementation of sophisticated tractography methods will lead to increasingly accurate maps of human anatomical connections. However, assessing the anatomical accuracy of DWI tractography is difficult because of the lack of independent knowledge of the true anatomical connections in humans. Here we investigate the future prospects of DWI-based connectional imaging by applying advanced tractography methods to an ex vivo DWI dataset of the macaque brain. The results of different tractography methods were compared with maps of known axonal projections from previous tracer studies in the macaque. Despite the exceptional quality of the DWI data, none of the methods demonstrated high anatomical accuracy. The methods that showed the highest sensitivity showed the lowest specificity, and vice versa. Additionally, anatomical accuracy was highly dependent upon parameters of the tractography algorithm, with different optimal values for mapping different pathways. These results suggest that there is an inherent limitation in determining long-range anatomical projections based on voxel-averaged estimates of local fiber orientation obtained from DWI data that is unlikely to be overcome by improvements in data acquisition and analysis alone.

  19. "Medicine show." Alice in Doctorland.

    PubMed

    1987-01-01

    This is an excerpt from the script of a 1939 play provided to the Institute of Social Medicine and Community Health by the Library of Congress Federal Theater Project Collection at George Mason University Library, Fairfax, Virginia, pages 2-1-8 thru 2-1-14. The Federal Theatre Project (FTP) was part of the New Deal program for the arts 1935-1939. Funded by the Works Progress Administration (WPA) its goal was to employ theater professionals from the relief rolls. A number of FTP plays deal with aspects of medicine and public health. Pageants, puppet shows and documentary plays celebrated progress in medical science while examining social controversies in medical services and the public health movement. "Medicine Show" sharply contrasts technological wonders with social backwardness. The play was rehearsed by the FTP but never opened because funding ended. A revised version ran on Broadway in 1940. The preceding comments are adapted from an excellent, well-illustrated review of five of these plays by Barabara Melosh: "The New Deal's Federal Theatre Project," Medical Heritage, Vol. 2, No. 1 (Jan/Feb 1986), pp. 36-47.

  20. What Do Blood Tests Show?

    MedlinePlus

    ... Range Results* Red blood cell (varies with altitude) Male: 5 to 6 million cells/mcL Female: 4 to 5 million cells/mcL ... cells/mcL Platelets 140,000 to 450,000 cells/mcL Hemoglobin (varies with altitude) Male: 14 to 17 gm/dL Female: 12 to ...

  1. Classification accuracy of the wrist-worn GENEA accelerometer

    PubMed Central

    Welch, Whitney A.; Bassett, David R.; Thompson, Dixie L.; Freedson, Patty S.; Staudenmayer, John W.; John, Dinesh; Steeves, Jeremy A.; Conger, Scott A.; Ceaser, Tyrone; Howe, Cheryl A.; Sasaki, Jeffer E.; Fitzhugh, Eugene C.

    2013-01-01

    Purpose The purpose of this study was to determine whether the published left-wrist cut-points for the triaxial GENEA accelerometer, are accurate for predicting intensity categories during structured activity bouts. Methods A convenience sample of 130 adults wore a GENEA accelerometer on their left wrist while performing 14 different lifestyle activities. During each activity, oxygen consumption was continuously measured using the Oxycon mobile. Statistical analysis used Spearman's rank correlations to determine the relationship between measured and estimated intensity classifications. Cross tabulation tables were constructed to show under- or over-estimation of misclassified intensities. One-way chi-square tests were used to determine whether the intensity classification accuracy for each activity differed from 80%. Results For all activities the GENEA accelerometer-based physical activity monitor explained 41.1% of the variance in energy expenditure. The intensity classification accuracy was 69.8% for sedentary activities, 44.9% for light activities, 46.2% for moderate activities, and 77.7% for vigorous activities. The GENEA correctly classified intensity for 52.9% of observations when all activities were examined; this increased to 61.5% with stationary cycling removed. Conclusion A wrist-worn triaxial accelerometer has modest intensity classification accuracy across a broad range of activities, when using the cut-points of Esliger et al. Although the sensitivity and specificity are less than those reported by Esliger et al., they are generally in the same range as those reported for waist-worn, uniaxial accelerometer cut-points. PMID:23584403

  2. Errors in spectral fingerprints and their effects on climate fingerprinting accuracy in the solar spectrum

    NASA Astrophysics Data System (ADS)

    Jin, Zhonghai; Sun, Moguo

    2017-02-01

    Using the Earth's reflected solar spectrum for climate change fingerprinting is an emerging research area. The spectral fingerprinting approach directly retrieves the changes in climate variables from the mean spectral data averaged across large space and time scales. To investigate this fingerprinting concept, we use ten years of satellite data to simulate the monthly and annual mean reflected solar spectra and the associated spectral fingerprints for different regions over the ocean. The interannual variations in the spectral data are derived and attributed to the interannual variations in the relevant climate variables. The fingerprinting retrieved changes in climate variables are then compared with the actual underlying variable changes from the observational data to evaluate the fingerprinting retrieval accuracy. Two important errors related to the fingerprinting approach, the nonlinearity error and the averaging error in the mean fingerprints, and their impact on the retrieval accuracy, are investigated. It is found that the averaging error increases but the nonlinearity error decreases as the region size increases. The averaging error has minimal effect on the fingerprinting retrieval accuracy in small regions but has more of an impact in large regions. In comparison, the effect of nonlinearity error on the retrieval accuracy decreases as the region size increases. It is also found that the fingerprinting retrieval accuracy is more sensitive to the nonlinearity error than to the averaging error. In addition, we compare the fingerprinting accuracy between using the monthly mean data and the annual mean data. The results show that on average higher retrieval accuracy is achieved when the annual mean data are used for the fingerprinting retrieval.

  3. [Accuracy evaluation of the TRMM satellite-based precipitation data over the mid-high latitudes].

    PubMed

    Cai, Yan-Cong; Jin, Chang-Jie; Wang, An-Zhi; Guan, De-Xin; Wu, Jia-Bing; Yuan, Feng-Hui; Xu, Lei-Lei; Bu, Chang-Qian

    2014-11-01

    Satellite-based precipitation product plays a significant role in analyzing spatial pattern of precipitation. TRMM 3B42 (3B42), as one of important precipitation products, is a key forcing factor for ecological, climate and hydrological models with its sufficient spatial and temporal scales. At present, there is still limited knowledge of accuracy and error structure of new version 3B42 V7, especially the lack of evaluating its accuracy in regions of mid-high latitudes, which restricts its application in the field of ecology, climate and hydrology. Based on 3B42 V7 product and data obtained from 53 weather stations in the period of 1998-2012 over Inner Mongolia, the paper evaluated the accuracy of 3B42 and revealed the spatial distribution of accuracy evaluation indices and its influencing factors. The result of overall accuracy evaluation indicated that there was overestimation of the amount of precipitation by 3B42 at daily, monthly and annual timescales. Error of 3B42 increased with the increasing timescale, and mean error and mean absolute error of daily precipitation were just -0.06 and 0.88 mm, respectively. It showed good performance for detecting the occurrence of rain events with equitable threat score (ETS) of 0.23, but slightly overestimated the frequency of rainy events. Moreover, altitude and average annual precipitation had impacts on data accuracy. The absolute error of precipitation decreased and yet the ability of detecting rain events be- came weak with the increasing altitude, while the effect of average annual precipitation on data accuracy was opposite.

  4. Improvements on the accuracy of beam bugs

    SciTech Connect

    Chen, Y J; Fessenden, T

    1998-09-02

    At LLNL resistive wall monitors are used to measure the current and position used on ETA-II show a droop in signal due to a fast redistribution time constant of the signals. This paper presents the analysis and experimental test of the beam bugs used for beam current and position measurements in and after the fast kicker. It concludes with an outline of present and future changes that can be made to improve the accuracy of these beam bugs. of intense electron beams in electron induction linacs and beam transport lines. These, known locally as "beam bugs", have been used throughout linear induction accelerators as essential diagnostics of beam current and location. Recently, the development of a fast beam kicker has required improvement in the accuracy of measuring the position of beams. By picking off signals at more than the usual four positions around the monitor, beam position measurement error can be greatly reduced. A second significant source of error is the mechanical variation of the resistor around the bug.

  5. Improvements on the accuracy of beam bugs

    SciTech Connect

    Chen, Y.J.; Fessenden, T.

    1998-08-17

    At LLNL resistive wall monitors are used to measure the current and position used on ETA-II show a droop in signal due to a fast redistribution time constant of the signals. This paper presents the analysis and experimental test of the beam bugs used for beam current and position measurements in and after the fast kicker. It concludes with an outline of present and future changes that can be made to improve the accuracy of these beam bugs. of intense electron beams in electron induction linacs and beam transport lines. These, known locally as ''beam bugs'', have been used throughout linear induction accelerators as essential diagnostics of beam current and location. Recently, the development of a fast beam kicker has required improvement in the accuracy of measuring the position of beams. By picking off signals at more than the usual four positions around the monitor, beam position measurement error can be greatly reduced. A second significant source of error is the mechanical variation of the resistor around the bug.

  6. "Show me" bioethics and politics.

    PubMed

    Christopher, Myra J

    2007-10-01

    Missouri, the "Show Me State," has become the epicenter of several important national public policy debates, including abortion rights, the right to choose and refuse medical treatment, and, most recently, early stem cell research. In this environment, the Center for Practical Bioethics (formerly, Midwest Bioethics Center) emerged and grew. The Center's role in these "cultural wars" is not to advocate for a particular position but to provide well researched and objective information, perspective, and advocacy for the ethical justification of policy positions; and to serve as a neutral convener and provider of a public forum for discussion. In this article, the Center's work on early stem cell research is a case study through which to argue that not only the Center, but also the field of bioethics has a critical role in the politics of public health policy.

  7. Phoenix Scoop Inverted Showing Rasp

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows the silver colored rasp protruding from NASA's Phoenix Mars Lander's Robotic Arm scoop. The scoop is inverted and the rasp is pointing up.

    Shown with its forks pointing toward the ground is the thermal and electrical conductivity probe, at the lower right. The Robotic Arm Camera is pointed toward the ground.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. ShowMe3D

    SciTech Connect

    Sinclair, Michael B

    2012-01-05

    ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.

  9. High accuracy broadband infrared spectropolarimetry

    NASA Astrophysics Data System (ADS)

    Krishnaswamy, Venkataramanan

    Mueller matrix spectroscopy or Spectropolarimetry combines conventional spectroscopy with polarimetry, providing more information than can be gleaned from spectroscopy alone. Experimental studies on infrared polarization properties of materials covering a broad spectral range have been scarce due to the lack of available instrumentation. This dissertation aims to fill the gap by the design, development, calibration and testing of a broadband Fourier Transform Infra-Red (FT-IR) spectropolarimeter. The instrument operates over the 3-12 mum waveband and offers better overall accuracy compared to the previous generation instruments. Accurate calibration of a broadband spectropolarimeter is a non-trivial task due to the inherent complexity of the measurement process. An improved calibration technique is proposed for the spectropolarimeter and numerical simulations are conducted to study the effectiveness of the proposed technique. Insights into the geometrical structure of the polarimetric measurement matrix is provided to aid further research towards global optimization of Mueller matrix polarimeters. A high performance infrared wire-grid polarizer is characterized using the spectropolarimeter. Mueller matrix spectrum measurements on Penicillin and pine pollen are also presented.

  10. ACCURACY OF CO2 SENSORS

    SciTech Connect

    Fisk, William J.; Faulkner, David; Sullivan, Douglas P.

    2008-10-01

    Are the carbon dioxide (CO2) sensors in your demand controlled ventilation systems sufficiently accurate? The data from these sensors are used to automatically modulate minimum rates of outdoor air ventilation. The goal is to keep ventilation rates at or above design requirements while adjusting the ventilation rate with changes in occupancy in order to save energy. Studies of energy savings from demand controlled ventilation and of the relationship of indoor CO2 concentrations with health and work performance provide a strong rationale for use of indoor CO2 data to control minimum ventilation rates1-7. However, this strategy will only be effective if, in practice, the CO2 sensors have a reasonable accuracy. The objective of this study was; therefore, to determine if CO2 sensor performance, in practice, is generally acceptable or problematic. This article provides a summary of study methods and findings ? additional details are available in a paper in the proceedings of the ASHRAE IAQ?2007 Conference8.

  11. Astrophysics with Microarcsecond Accuracy Astrometry

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.

    2008-01-01

    Space-based astrometry promises to provide a powerful new tool for astrophysics. At a precision level of a few microarcsonds, a wide range of phenomena are opened up for study. In this paper we discuss the capabilities of the SIM Lite mission, the first space-based long-baseline optical interferometer, which will deliver parallaxes to 4 microarcsec. A companion paper in this volume will cover the development and operation of this instrument. At the level that SIM Lite will reach, better than 1 microarcsec in a single measurement, planets as small as one Earth can be detected around many dozen of the nearest stars. Not only can planet masses be definitely measured, but also the full orbital parameters determined, allowing study of system stability in multiple planet systems. This capability to survey our nearby stellar neighbors for terrestrial planets will be a unique contribution to our understanding of the local universe. SIM Lite will be able to tackle a wide range of interesting problems in stellar and Galactic astrophysics. By tracing the motions of stars in dwarf spheroidal galaxies orbiting our Milky Way, SIM Lite will probe the shape of the galactic potential history of the formation of the galaxy, and the nature of dark matter. Because it is flexibly scheduled, the instrument can dwell on faint targets, maintaining its full accuracy on objects as faint as V=19. This paper is a brief survey of the diverse problems in modern astrophysics that SIM Lite will be able to address.

  12. [Accuracy of HDL cholesterol measurements].

    PubMed

    Niedmann, P D; Luthe, H; Wieland, H; Schaper, G; Seidel, D

    1983-02-01

    The widespread use of different methods for the determination of HDL-cholesterol (in Europe: sodium phosphotungstic acid/MgCl2) in connection with enzymatic procedures (in the USA: heparin/MnCl2 followed by the Liebermann-Burchard method) but common reference values makes it necessary to evaluate not only accuracy, specificity, and precision of the precipitation step but also of the subsequent cholesterol determination. A high ratio of serum vs. concentrated precipitation reagent (10:1 V/V) leads to the formation of variable amounts of delta-3.5-cholestadiene. This substance is not recognized by cholesterol oxidase but leads to an 1.6 times overestimation by the Liebermann-Burchard method. Therefore, errors in HDL-cholesterol determination should be considered and differences up to 30% may occur between HDL-cholesterol values determined by the different techniques (heparin/MnCl2 - Liebermann-Burchard and NaPW/MgCl2-CHOD-PAP).

  13. Accuracy of remotely sensed data: Sampling and analysis procedures

    NASA Technical Reports Server (NTRS)

    Congalton, R. G.; Oderwald, R. G.; Mead, R. A.

    1982-01-01

    A review and update of the discrete multivariate analysis techniques used for accuracy assessment is given. A listing of the computer program written to implement these techniques is given. New work on evaluating accuracy assessment using Monte Carlo simulation with different sampling schemes is given. The results of matrices from the mapping effort of the San Juan National Forest is given. A method for estimating the sample size requirements for implementing the accuracy assessment procedures is given. A proposed method for determining the reliability of change detection between two maps of the same area produced at different times is given.

  14. Air traffic control surveillance accuracy and update rate study

    NASA Technical Reports Server (NTRS)

    Craigie, J. H.; Morrison, D. D.; Zipper, I.

    1973-01-01

    The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

  15. Improvement of focus accuracy on processed wafer

    NASA Astrophysics Data System (ADS)

    Higashibata, Satomi; Komine, Nobuhiro; Fukuhara, Kazuya; Koike, Takashi; Kato, Yoshimitsu; Hashimoto, Kohji

    2013-04-01

    As feature size shrinkage in semiconductor device progress, process fluctuation, especially focus strongly affects device performance. Because focus control is an ongoing challenge in optical lithography, various studies have sought for improving focus monitoring and control. Focus errors are due to wafers, exposure tools, reticles, QCs, and so on. Few studies are performed to minimize the measurement errors of auto focus (AF) sensors of exposure tool, especially when processed wafers are exposed. With current focus measurement techniques, the phase shift grating (PSG) focus monitor 1) has been already proposed and its basic principle is that the intensity of the diffraction light of the mask pattern is made asymmetric by arranging a π/2 phase shift area on a reticle. The resist pattern exposed at the defocus position is shifted on the wafer and shifted pattern can be easily measured using an overlay inspection tool. However, it is difficult to measure shifted pattern for the pattern on the processed wafer because of interruptions caused by other patterns in the underlayer. In this paper, we therefore propose "SEM-PSG" technique, where the shift of the PSG resist mark is measured by employing critical dimension-scanning electron microscope (CD-SEM) to measure the focus error on the processed wafer. First, we evaluate the accuracy of SEM-PSG technique. Second, by applying the SEM-PSG technique and feeding the results back to the exposure, we evaluate the focus accuracy on processed wafers. By applying SEM-PSG feedback, the focus accuracy on the processed wafer was improved from 40 to 29 nm in 3σ.

  16. Ultrasound-Guided Needle Technique Accuracy

    PubMed Central

    Johnson, Angela N.; Peiffer, Jeffery S.; Halmann, Nahi; Delaney, Luke; Owen, Cindy A.; Hersh, Jeff

    2017-01-01

    Background and Objectives Ultrasound-guided regional anesthesia facilitates an approach to sensitive targets such as nerve clusters without contact or inadvertent puncture. We compared accuracy of needle placement with a novel passive magnetic ultrasound needle guidance technology (NGT) versus conventional ultrasound (CU) with echogenic needles. Methods Sixteen anesthesiologists and 19 residents performed a series of 16 needle insertion tasks each, 8 using NGT (n = 280) and 8 using CU (n = 280), in high-fidelity porcine phantoms. Tasks were stratified based on aiming to contact (target-contact) or place in close proximity with (target-proximity) targets, needle gauge (no. 18/no. 22), and in-plane (IP) or out-of-plane (OOP) approach. Distance to the target, task completion by aim, number of passes, and number of tasks completed on the first pass were reported. Results Needle guidance technology significantly improved distance, task completion, number of passes, and completion on the first pass compared with CU for both IP and OOP approaches (P ≤ 0.001). Average NGT distance to target was lower by 57.1% overall (n = 560, 1.5 ± 2.4 vs 3.5 ± 3.7 mm), 38.5% IP (n = 140, 1.6 ± 2.6 vs 2.6 ± 2.8 mm), and 68.2% OOP (n = 140, 1.4 ± 2.2 vs 4.4 ± 4.3 mm) (all P ≤ 0.01). Subgroup analyses revealed accuracy gains were largest among target-proximity tasks performed by residents and for OOP approaches. Needle guidance technology improved first-pass completion from 214 (76.4%) per 280 to 249 (88.9%) per 280, a significant improvement of 16.4% (P = 0.001). Conclusions Passive magnetic NGT can improve accuracy of needle procedures, particularly among OOP procedures requiring close approach to sensitive targets, such as nerve blocks in anesthesiology practice. PMID:28079754

  17. Accuracy of predicting genomic breeding values for residual feed intake in Angus and Charolais beef cattle.

    PubMed

    Chen, L; Schenkel, F; Vinsky, M; Crews, D H; Li, C

    2013-10-01

    In beef cattle, phenotypic data that are difficult and/or costly to measure, such as feed efficiency, and DNA marker genotypes are usually available on a small number of animals of different breeds or populations. To achieve a maximal accuracy of genomic prediction using the phenotype and genotype data, strategies for forming a training population to predict genomic breeding values (GEBV) of the selection candidates need to be evaluated. In this study, we examined the accuracy of predicting GEBV for residual feed intake (RFI) based on 522 Angus and 395 Charolais steers genotyped on SNP with the Illumina Bovine SNP50 Beadchip for 3 training population forming strategies: within breed, across breed, and by pooling data from the 2 breeds (i.e., combined). Two other scenarios with the training and validation data split by birth year and by sire family within a breed were also investigated to assess the impact of genetic relationships on the accuracy of genomic prediction. Three statistical methods including the best linear unbiased prediction with the relationship matrix defined based on the pedigree (PBLUP), based on the SNP genotypes (GBLUP), and a Bayesian method (BayesB) were used to predict the GEBV. The results showed that the accuracy of the GEBV prediction was the highest when the prediction was within breed and when the validation population had greater genetic relationships with the training population, with a maximum of 0.58 for Angus and 0.64 for Charolais. The within-breed prediction accuracies dropped to 0.29 and 0.38, respectively, when the validation populations had a minimal pedigree link with the training population. When the training population of a different breed was used to predict the GEBV of the validation population, that is, across-breed genomic prediction, the accuracies were further reduced to 0.10 to 0.22, depending on the prediction method used. Pooling data from the 2 breeds to form the training population resulted in accuracies increased

  18. Laser damage properties of films with different surface accuracy of substrates

    NASA Astrophysics Data System (ADS)

    Ge, Jinman; Su, Junhong

    2014-09-01

    The analysis of laser damage properties of films is the focus of most concern in recent years. Many properties of the film have been studied, but the surface accuracy of the substrates shouldn't be ignored. TiO2 films are prepared on K9 glass substrates with different surface accuracy by ion beam assistant deposition technique. The films' surface morphology, microstructure and thickness are been analyzed. It shows that the substrates with different surface accuracy have some impact on thin film growth and make different micro-structures of thin film. According to the international standard requirements of the damage threshold, the films' damage threshold is measured on the films' laser-induced damage threshold test platform composed with 1064 nm Nd: YAG laser. The results indicate that the laser damage threshold of the film deposited on the substrate with the better surface accuracy is higher, and the substrate with high accuracy can improve the laser damage resistance of the film.

  19. Sparsity Is Better with Stability: Combining Accuracy and Stability for Model Selection in Brain Decoding

    PubMed Central

    Baldassarre, Luca; Pontil, Massimiliano; Mourão-Miranda, Janaina

    2017-01-01

    Structured sparse methods have received significant attention in neuroimaging. These methods allow the incorporation of domain knowledge through additional spatial and temporal constraints in the predictive model and carry the promise of being more interpretable than non-structured sparse methods, such as LASSO or Elastic Net methods. However, although sparsity has often been advocated as leading to more interpretable models it can also lead to unstable models under subsampling or slight changes of the experimental conditions. In the present work we investigate the impact of using stability/reproducibility as an additional model selection criterion1 on several different sparse (and structured sparse) methods that have been recently applied for fMRI brain decoding. We compare three different model selection criteria: (i) classification accuracy alone; (ii) classification accuracy and overlap between the solutions; (iii) classification accuracy and correlation between the solutions. The methods we consider include LASSO, Elastic Net, Total Variation, sparse Total Variation, Laplacian and Graph Laplacian Elastic Net (GraphNET). Our results show that explicitly accounting for stability/reproducibility during the model optimization can mitigate some of the instability inherent in sparse methods. In particular, using accuracy and overlap between the solutions as a joint optimization criterion can lead to solutions that are more similar in terms of accuracy, sparsity levels and coefficient maps even when different sparsity methods are considered. PMID:28261042

  20. Quantification of Proton Dose Calculation Accuracy in the Lung

    SciTech Connect

    Grassberger, Clemens; Daartz, Juliane; Dowdell, Stephen; Ruggieri, Thomas; Sharp, Greg; Paganetti, Harald

    2014-06-01

    Purpose: To quantify the accuracy of a clinical proton treatment planning system (TPS) as well as Monte Carlo (MC)–based dose calculation through measurements and to assess the clinical impact in a cohort of patients with tumors located in the lung. Methods and Materials: A lung phantom and ion chamber array were used to measure the dose to a plane through a tumor embedded in the lung, and to determine the distal fall-off of the proton beam. Results were compared with TPS and MC calculations. Dose distributions in 19 patients (54 fields total) were simulated using MC and compared to the TPS algorithm. Results: MC increased dose calculation accuracy in lung tissue compared with the TPS and reproduced dose measurements in the target to within ±2%. The average difference between measured and predicted dose in a plane through the center of the target was 5.6% for the TPS and 1.6% for MC. MC recalculations in patients showed a mean dose to the clinical target volume on average 3.4% lower than the TPS, exceeding 5% for small fields. For large tumors, MC also predicted consistently higher V5 and V10 to the normal lung, because of a wider lateral penumbra, which was also observed experimentally. Critical structures located distal to the target could show large deviations, although this effect was highly patient specific. Range measurements showed that MC can reduce range uncertainty by a factor of ∼2: the average (maximum) difference to the measured range was 3.9 mm (7.5 mm) for MC and 7 mm (17 mm) for the TPS in lung tissue. Conclusion: Integration of Monte Carlo dose calculation techniques into the clinic would improve treatment quality in proton therapy for lung cancer by avoiding systematic overestimation of target dose and underestimation of dose to normal lung. In addition, the ability to confidently reduce range margins would benefit all patients by potentially lowering toxicity.

  1. Utilizing the Global Land Cover 2000 reference dataset for a comparative accuracy assessment of 1 km global land cover maps

    NASA Astrophysics Data System (ADS)

    Schultz, M.; Tsendbazazr, N. E.; Herold, M.; Jung, M.; Mayaux, P.; Goehman, H.

    2015-04-01

    Many investigators use global land cover (GLC) maps for different purposes, such as an input for global climate models. The current GLC maps used for such purposes are based on different remote sensing data, methodologies and legends. Consequently, comparison of GLC maps is difficult and information about their relative utility is limited. The objective of this study is to analyse and compare the thematic accuracies of GLC maps (i.e., IGBP-DISCover, UMD, MODIS, GLC2000 and SYNMAP) at 1 km resolutions by (a) re-analysing the GLC2000 reference dataset, (b) applying a generalized GLC legend and (c) comparing their thematic accuracies at different homogeneity levels. The accuracy assessment was based on the GLC2000 reference dataset with 1253 samples that were visually interpreted. The legends of the GLC maps and the reference datasets were harmonized into 11 general land cover classes. There results show that the map accuracy estimates vary up to 10-16% depending on the homogeneity of the reference point (HRP) for all the GLC maps. An increase of the HRP resulted in higher overall accuracies but reduced accuracy confidence for the GLC maps due to less number of accountable samples. The overall accuracy of the SYNMAP was the highest at any HRP level followed by the GLC2000. The overall accuracies of the maps also varied by up to 10% depending on the definition of agreement between the reference and map categories in heterogeneous landscape. A careful consideration of heterogeneous landscape is therefore recommended for future accuracy assessments of land cover maps.

  2. Ground Truth Sampling and LANDSAT Accuracy Assessment

    NASA Technical Reports Server (NTRS)

    Robinson, J. W.; Gunther, F. J.; Campbell, W. J.

    1982-01-01

    It is noted that the key factor in any accuracy assessment of remote sensing data is the method used for determining the ground truth, independent of the remote sensing data itself. The sampling and accuracy procedures developed for nuclear power plant siting study are described. The purpose of the sampling procedure was to provide data for developing supervised classifications for two study sites and for assessing the accuracy of that and the other procedures used. The purpose of the accuracy assessment was to allow the comparison of the cost and accuracy of various classification procedures as applied to various data types.

  3. Casimir experiments showing saturation effects

    SciTech Connect

    Sernelius, Bo E.

    2009-10-15

    We address several different Casimir experiments where theory and experiment disagree. First out is the classical Casimir force measurement between two metal half spaces; here both in the form of the torsion pendulum experiment by Lamoreaux and in the form of the Casimir pressure measurement between a gold sphere and a gold plate as performed by Decca et al.; theory predicts a large negative thermal correction, absent in the high precision experiments. The third experiment is the measurement of the Casimir force between a metal plate and a laser irradiated semiconductor membrane as performed by Chen et al.; the change in force with laser intensity is larger than predicted by theory. The fourth experiment is the measurement of the Casimir force between an atom and a wall in the form of the measurement by Obrecht et al. of the change in oscillation frequency of a {sup 87}Rb Bose-Einstein condensate trapped to a fused silica wall; the change is smaller than predicted by theory. We show that saturation effects can explain the discrepancies between theory and experiment observed in all these cases.

  4. Understanding the delayed-keyword effect on metacomprehension accuracy.

    PubMed

    Thiede, Keith W; Dunlosky, John; Griffin, Thomas D; Wiley, Jennifer

    2005-11-01

    The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M. Anderson, 2003; K. W. Thiede, M. C. M. Anderson, & D. Therriault, 2003). The delayed and immediate conditions in these studies confounded the delay between reading and generation tasks with other task lags, including the lag between multiple generation tasks and the lag between generation tasks and judgments. The first 2 experiments disentangle these confounded manipulations and provide clear evidence that the delay between reading and keyword generation is the only lag critical to improving metacomprehension accuracy. The 3rd and 4th experiments show that not all delayed tasks produce improvements and suggest that delayed generative tasks provide necessary diagnostic cues about comprehension for improving metacomprehension accuracy.

  5. The effect of superior auditory skills on vocal accuracy

    NASA Astrophysics Data System (ADS)

    Amir, Ofer; Amir, Noam; Kishon-Rabin, Liat

    2003-02-01

    The relationship between auditory perception and vocal production has been typically investigated by evaluating the effect of either altered or degraded auditory feedback on speech production in either normal hearing or hearing-impaired individuals. Our goal in the present study was to examine this relationship in individuals with superior auditory abilities. Thirteen professional musicians and thirteen nonmusicians, with no vocal or singing training, participated in this study. For vocal production accuracy, subjects were presented with three tones. They were asked to reproduce the pitch using the vowel /a/. This procedure was repeated three times. The fundamental frequency of each production was measured using an autocorrelation pitch detection algorithm designed for this study. The musicians' superior auditory abilities (compared to the nonmusicians) were established in a frequency discrimination task reported elsewhere. Results indicate that (a) musicians had better vocal production accuracy than nonmusicians (production errors of 1/2 a semitone compared to 1.3 semitones, respectively); (b) frequency discrimination thresholds explain 43% of the variance of the production data, and (c) all subjects with superior frequency discrimination thresholds showed accurate vocal production; the reverse relationship, however, does not hold true. In this study we provide empirical evidence to the importance of auditory feedback on vocal production in listeners with superior auditory skills.

  6. Prospective memory mediated by interoceptive accuracy: a psychophysiological approach

    PubMed Central

    Tochizawa, Saiko; Shibata, Midori; Terasawa, Yuri

    2016-01-01

    Previous studies on prospective memory (PM), defined as memory for future intentions, suggest that psychological stress enhances successful PM retrieval. However, the mechanisms underlying this notion remain poorly understood. We hypothesized that PM retrieval is achieved through interaction with autonomic nervous activity, which is mediated by the individual accuracy of interoceptive awareness, as measured by the heartbeat detection task. In this study, the relationship between cardiac reactivity and retrieval of delayed intentions was evaluated using the event-based PM task. Participants were required to detect PM target letters while engaged in an ongoing 2-back working memory task. The results demonstrated that individuals with higher PM task performance had a greater increase in heart rate on PM target presentation. Also, higher interoceptive perceivers showed better PM task performance. This pattern was not observed for working memory task performance. These findings suggest that cardiac afferent signals enhance PM retrieval, which is mediated by individual levels of interoceptive accuracy. This article is part of the themed issue ‘Interoception beyond homeostasis: affect, cognition and mental health’. PMID:28080964

  7. Novel method for high accuracy figure measurement of optical flat

    NASA Astrophysics Data System (ADS)

    E, Kewei; Li, Dahai; Yang, Lijie; Guo, Guangrao; Li, Mengyang; Wang, Xuemin; Zhang, Tao; Xiong, Zhao

    2017-01-01

    Phase Measuring Deflectometry (PMD) is a non-contact, high dynamic-range and full-field metrology which becomes a serious competitor to interferometry. However, the accuracy of deflectometry metrology is strongly influenced by the level of the calibrations, including test geometry, imaging pin-hole camera and digital display. In this paper, we propose a novel method that can measure optical flat surface figure to a high accuracy. We first calibrate the camera using a checker pattern shown on a LCD display at six different orientations, and the last orientation is aligned at the same position as the test optical flat. By using this method, lens distortions and the mapping relationship between the CCD pixels and the subaperture coordinates on the test optical flat can be determined at the same time. To further reduce the influence of the calibration errors on measurements, a reference optical flat with a high quality surface is measured, and then the system errors in our PMD setup can be eliminated by subtracting the figure of the reference flat from the figure of the test flat. Although any expensive coordinates measuring machine, such as laser tracker and coordinates measuring machine are not applied in our measurement, our experimental results of optical flat figure from low to high order aberrations still show a good agreement with that from the Fizeau interferometer.

  8. Evaluating the Accuracy of Hessian Approximations for Direct Dynamics Simulations.

    PubMed

    Zhuang, Yu; Siebert, Matthew R; Hase, William L; Kay, Kenneth G; Ceotto, Michele

    2013-01-08

    Direct dynamics simulations are a very useful and general approach for studying the atomistic properties of complex chemical systems, since an electronic structure theory representation of a system's potential energy surface is possible without the need for fitting an analytic potential energy function. In this paper, recently introduced compact finite difference (CFD) schemes for approximating the Hessian [J. Chem. Phys.2010, 133, 074101] are tested by employing the monodromy matrix equations of motion. Several systems, including carbon dioxide and benzene, are simulated, using both analytic potential energy surfaces and on-the-fly direct dynamics. The results show, depending on the molecular system, that electronic structure theory Hessian direct dynamics can be accelerated up to 2 orders of magnitude. The CFD approximation is found to be robust enough to deal with chaotic motion, concomitant with floppy and stiff mode dynamics, Fermi resonances, and other kinds of molecular couplings. Finally, the CFD approximations allow parametrical tuning of different CFD parameters to attain the best possible accuracy for different molecular systems. Thus, a direct dynamics simulation requiring the Hessian at every integration step may be replaced with an approximate Hessian updating by tuning the appropriate accuracy.

  9. Spectral reflectance inversion with high accuracy on green target

    NASA Astrophysics Data System (ADS)

    Jiang, Le; Yuan, Jinping; Li, Yong; Bai, Tingzhu; Liu, Shuoqiong; Jin, Jianzhou; Shen, Jiyun

    2016-09-01

    Using Landsat-7 ETM remote sensing data, the inversion of spectral reflectance of green wheat in visible and near infrared waveband in Yingke, China is studied. In order to solve the problem of lower inversion accuracy, custom atmospheric conditions method based on moderate resolution transmission model (MODTRAN) is put forward. Real atmospheric parameters are considered when adopting this method. The atmospheric radiative transfer theory to calculate atmospheric parameters is introduced first and then the inversion process of spectral reflectance is illustrated in detail. At last the inversion result is compared with simulated atmospheric conditions method which was a widely used method by previous researchers. The comparison shows that the inversion accuracy of this paper's method is higher in all inversion bands; the inversed spectral reflectance curve by this paper's method is more similar to the measured reflectance curve of wheat and better reflects the spectral reflectance characteristics of green plant which is very different from green artificial target. Thus, whether a green target is a plant or artificial target can be judged by reflectance inversion based on remote sensing image. This paper's research is helpful for the judgment of green artificial target hidden in the greenery, which has a great significance on the precise strike of green camouflaged weapons in military field.

  10. Evaluation of accuracy and reliability of PulseOn optical heart rate monitoring device.

    PubMed

    Delgado-Gonzalo, Ricard; Parak, Jakub; Tarniceriu, Adrian; Renevey, Philippe; Bertschi, Mattia; Korhonen, Ilkka

    2015-08-01

    PulseOn is a wrist-worn optical heart rate (HR) monitor based on photoplethysmography. It utilizes multi-wavelength technology and optimized sensor geometry to monitor blood flow at different depths of skin tissue, and it dynamically adapts to an optimal measurement depth in different conditions. Movement artefacts are reduced by adaptive movement-cancellation algorithms and optimized mechanics, which stabilize the sensor-to-skin contact. In this paper, we evaluated the accuracy and reliability of PulseOn technology against ECG-derived HR in laboratory conditions during a wide range of physical activities and also during outdoor sports. In addition, we compared the performance to another on-the-shelf wrist-worn consumer product Mio LINK(®). The results showed PulseOn reliability (% of time with error <;10bpm) of 94.5% with accuracy (100% - mean absolute percentage error) 96.6% as compared to ECG (vs 86.6% and 94.4% for Mio LINK(®), correspondingly) during laboratory protocol. Similar or better reliability and accuracy was seen during normal outdoor sports activities. The results show that PulseOn provides reliability and accuracy similar to traditional chest strap ECG HR monitors during cardiovascular exercise.

  11. Design of a high linearity and high gain accuracy analog baseband circuit for DAB receiver

    NASA Astrophysics Data System (ADS)

    Li, Ma; Zhigong, Wang; Jian, Xu; Yiqiang, Wu; Junliang, Wang; Mi, Tian; Jianping, Chen

    2015-02-01

    An analog baseband circuit of high linearity and high gain accuracy for a digital audio broadcasting receiver is implemented in a 0.18-μm RFCMOS process. The circuit comprises a 3rd-order active-RC complex filter (CF) and a programmable gain amplifier (PGA). An automatic tuning circuit is also designed to tune the CF's pass band. Instead of the class-A fully differential operational amplifier (FDOPA) adopted in the conventional CF and PGA design, a class-AB FDOPA is specially employed in this circuit to achieve a higher linearity and gain accuracy for its large current swing capability with lower static current consumption. In the PGA circuit, a novel DC offset cancellation technique based on the MOS resistor is introduced to reduce the settling time significantly. A reformative switching network is proposed, which can eliminate the switch resistor's influence on the gain accuracy of the PGA. The measurement result shows the gain range of the circuit is 10-50 dB with a 1-dB step size, and the gain accuracy is less than ±0.3 dB. The OIP3 is 23.3 dBm at the gain of 10 dB. Simulation results show that the settling time is reduced from 100 to 1 ms. The image band rejection is about 40 dB. It only draws 4.5 mA current from a 1.8 V supply voltage.

  12. The effect of accuracy motivation on anchoring and adjustment: do people adjust from provided anchors?

    PubMed

    Simmons, Joseph P; LeBoeuf, Robyn A; Nelson, Leif D

    2010-12-01

    Increasing accuracy motivation (e.g., by providing monetary incentives for accuracy) often fails to increase adjustment away from provided anchors, a result that has led researchers to conclude that people do not effortfully adjust away from such anchors. We challenge this conclusion. First, we show that people are typically uncertain about which way to adjust from provided anchors and that this uncertainty often causes people to believe that they have initially adjusted too far away from such anchors (Studies 1a and 1b). Then, we show that although accuracy motivation fails to increase the gap between anchors and final estimates when people are uncertain about the direction of adjustment, accuracy motivation does increase anchor-estimate gaps when people are certain about the direction of adjustment, and that this is true regardless of whether the anchors are provided or self-generated (Studies 2, 3a, 3b, and 5). These results suggest that people do effortfully adjust away from provided anchors but that uncertainty about the direction of adjustment makes that adjustment harder to detect than previously assumed. This conclusion has important theoretical implications, suggesting that currently emphasized distinctions between anchor types (self-generated vs. provided) are not fundamental and that ostensibly competing theories of anchoring (selective accessibility and anchoring-and-adjustment) are complementary.

  13. Enhancing Science Performance in Students with Learning Disabilities Using Cover, Copy, and Compare: A Student Shows the Way.

    ERIC Educational Resources Information Center

    Smith, Tawnya J.; Dittmer, Karen I.; Skinner, Christopher H.

    2002-01-01

    In the current study a multiple baseline across tasks design was used to determine if the self-managed academic intervention known as cover, copy, and compare (CCC) could be used to enhance accuracy in identifying parts of the human heart in three students with learning disabilities. Results showed that immediately after implementing the CCC…

  14. TRASYS: Checkout of accuracy of direct irradiation calculations for discs, trapezoids, cones, and circular paraboloids

    NASA Technical Reports Server (NTRS)

    Mackeen, R. C.

    1977-01-01

    Results of the direct irradiation link of the TRASYS program are evaluated. Several surface configurations were investigated. The accuracy of the results was examined for simple cases where the answers were analytically known. By varying an accuracy factor in the program, the amount of computer time needed to achieve different degress of accuracy was determined.

  15. Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions – Changes in Accuracy over Time

    PubMed Central

    Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

    2015-01-01

    Background Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven’t been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their

  16. Accuracy of the Cloud Integrating Nephelometer

    NASA Technical Reports Server (NTRS)

    Gerber, Hermann E.

    2004-01-01

    Potential error sources for measurements with the Cloud Integrating Nephelometer (CIN) are discussed and analyzed, including systematic errors of the measurement approach, flow and particle-trajectory deviations at flight velocity, ice-crystal breakup on probe surfaces, and errors in calibration and developing scaling constants. It is concluded that errors are minimal, and that the accuracy of the CIN should be close to the systematic behavior of the CIN derived in Gerber et al (2000). Absolute calibration of the CIN with a transmissometer operating co-located in a mountain-top cloud shows that the earlier scaling constant for the optical extinction coefficient obtained by other means is within 5% of the absolute calibration value, and that the CIN measurements on the Citation aircraft flights during the CRYSTAL-FACE study are accurate.

  17. Mimas Showing False Colors #1

    NASA Technical Reports Server (NTRS)

    2005-01-01

    False color images of Saturn's moon, Mimas, reveal variation in either the composition or texture across its surface.

    During its approach to Mimas on Aug. 2, 2005, the Cassini spacecraft narrow-angle camera obtained multi-spectral views of the moon from a range of 228,000 kilometers (142,500 miles).

    The image at the left is a narrow angle clear-filter image, which was separately processed to enhance the contrast in brightness and sharpness of visible features. The image at the right is a color composite of narrow-angle ultraviolet, green, infrared and clear filter images, which have been specially processed to accentuate subtle changes in the spectral properties of Mimas' surface materials. To create this view, three color images (ultraviolet, green and infrared) were combined into a single black and white picture that isolates and maps regional color differences. This 'color map' was then superimposed over the clear-filter image at the left.

    The combination of color map and brightness image shows how the color differences across the Mimas surface materials are tied to geological features. Shades of blue and violet in the image at the right are used to identify surface materials that are bluer in color and have a weaker infrared brightness than average Mimas materials, which are represented by green.

    Herschel crater, a 140-kilometer-wide (88-mile) impact feature with a prominent central peak, is visible in the upper right of each image. The unusual bluer materials are seen to broadly surround Herschel crater. However, the bluer material is not uniformly distributed in and around the crater. Instead, it appears to be concentrated on the outside of the crater and more to the west than to the north or south. The origin of the color differences is not yet understood. It may represent ejecta material that was excavated from inside Mimas when the Herschel impact occurred. The bluer color of these materials may be caused by subtle differences in

  18. Dimensional accuracy of 3D printed vertebra

    NASA Astrophysics Data System (ADS)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  19. The empirical accuracy of uncertain inference models

    NASA Technical Reports Server (NTRS)

    Vaughan, David S.; Yadrick, Robert M.; Perrin, Bruce M.; Wise, Ben P.

    1987-01-01

    Uncertainty is a pervasive feature of the domains in which expert systems are designed to function. Research design to test uncertain inference methods for accuracy and robustness, in accordance with standard engineering practice is reviewed. Several studies were conducted to assess how well various methods perform on problems constructed so that correct answers are known, and to find out what underlying features of a problem cause strong or weak performance. For each method studied, situations were identified in which performance deteriorates dramatically. Over a broad range of problems, some well known methods do only about as well as a simple linear regression model, and often much worse than a simple independence probability model. The results indicate that some commercially available expert system shells should be used with caution, because the uncertain inference models that they implement can yield rather inaccurate results.

  20. High Accuracy 3D Processing of Satellite Imagery

    NASA Technical Reports Server (NTRS)

    Gruen, A.; Zhang, L.; Kocaman, S.

    2007-01-01

    Automatic DSM/DTM generation reproduces not only general features, but also detailed features of the terrain relief. Height accuracy of around 1 pixel in cooperative terrain. RMSE values of 1.3-1.5 m (1.0-2.0 pixels) for IKONOS and RMSE values of 2.9-4.6 m (0.5-1.0 pixels) for SPOT5 HRS. For 3D city modeling, the manual and semi-automatic feature extraction capability of SAT-PP provides a good basis. The tools of SAT-PP allowed the stereo-measurements of points on the roofs in order to generate a 3D city model with CCM The results show that building models with main roof structures can be successfully extracted by HRSI. As expected, with Quickbird more details are visible.

  1. Likable co-witnesses increase eyewitness accuracy and decrease suggestibility.

    PubMed

    Kieckhaefer, Jenna M; Wright, Daniel B

    2015-01-01

    This study examines the impact of likability on memory accuracy and memory conformity between two previously unacquainted individuals. After viewing a crime, eyewitnesses often talk to one another and may find each other likable or dislikable. One hundred twenty-seven undergraduate students arrived at the laboratory with an unknown confederate and were assigned to a likability condition (i.e., control, likable or dislikable). Together, the pair viewed pictures and was then tested on their memory for those pictures in such a way that the participant knew the confederate's response. Thus, the participant's response could be influenced both by his or her own memory and by the answers of the confederate. Participants in the likable condition were more accurate and less influenced by the confederate, compared with the other conditions. Results are discussed in relation to research that shows people are more influenced by friends than strangers and in relation to establishing positive rapport in forensic interviewing.

  2. Micro-vision-based displacement measurement with high accuracy

    NASA Astrophysics Data System (ADS)

    Lu, Qinghua; Zhang, Xianmin; Fan, Yanbin

    2011-12-01

    The micro-motion stages are widely used in micro/nano manufacturing technology. In this paper, an integrated approach for measuring micro-displacement of micro-motion stage that incorporates motion estimation algorithm into the computer microvision is proposed. At first, the basic principle of the computer microvision measurement is analyzed. Then, a robust multiscale motion estimation algorithm for micro-motion measurement is proposed. Finally, the microdisplacement of the micro-motion stage based on the piezoelectric ceramic actuators and the compliant mechanisms is measured using the integrated approach. The maximal bias of the proposed approach reached 13 nm. Experimental results show that the new integrated method can measure micro-displacement with nanometer accuracy.

  3. DEM extraction and its accuracy analysis with ground-based SAR interferometry

    NASA Astrophysics Data System (ADS)

    Dong, J.; Yue, J. P.; Li, L. H.

    2014-03-01

    Two altimetry models extracting DEM (Digital Elevation Model) with the GBSAR (Ground-Based Synthetic Aperture Radar) technology are studied and their accuracies are analyzed in detail. The approximate and improved altimetry models of GBSAR were derived from the spaceborne radar altimetry based on the principles of the GBSAR technology. The error caused by the parallel ray approximation in the approximate model was analyzed quantitatively, and the results show that the errors cannot be ignored for the ground-based radar system. For the improved altimetry model, the elevation error expression can be acquired by simulating and analyzing the error propagation coefficients of baseline length, wavelength, differential phase and range distance in the mathematical model. By analyzing the elevation error with the baseline and range distance, the results show that the improved altimetry model is suitable for high-precision DEM and the accuracy can be improved by adjusting baseline and shortening slant distance.

  4. Accuracy of analyses of microelectronics nanostructures in atom probe tomography

    NASA Astrophysics Data System (ADS)

    Vurpillot, F.; Rolland, N.; Estivill, R.; Duguay, S.; Blavette, D.

    2016-07-01

    The routine use of atom probe tomography (APT) as a nano-analysis microscope in the semiconductor industry requires the precise evaluation of the metrological parameters of this instrument (spatial accuracy, spatial precision, composition accuracy or composition precision). The spatial accuracy of this microscope is evaluated in this paper in the analysis of planar structures such as high-k metal gate stacks. It is shown both experimentally and theoretically that the in-depth accuracy of reconstructed APT images is perturbed when analyzing this structure composed of an oxide layer of high electrical permittivity (higher-k dielectric constant) that separates the metal gate and the semiconductor channel of a field emitter transistor. Large differences in the evaporation field between these layers (resulting from large differences in material properties) are the main sources of image distortions. An analytic model is used to interpret inaccuracy in the depth reconstruction of these devices in APT.

  5. A Stable and Conservative Interface Treatment of Arbitrary Spatial Accuracy

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Nordstrom, Jan; Gottlieb, David

    1998-01-01

    Stable and accurate interface conditions are derived for the linear advection-diffusion equation. The conditions are functionally independent of the spatial order of accuracy and rely only on the form of the discrete operator. We focus on high-order finite-difference operators that satisfy the summation-by-parts (SBP) property. We prove that stability is a natural consequence of the SBP operators used in conjunction with the new boundary conditions. In addition, we show that the interface treatments are conservative. New finite-difference operators of spatial accuracy up to sixth order are constructed: these operators satisfy the SBP property. Finite-difference operators are shown to admit design accuracy (p(sup th)-order global accuracy) when (p - 1)(sup th)-order stencil closures are used near the boundaries if the physical boundary conditions are implemented to at least p(sup th)-order accuracy. Stability and accuracy are demonstrated on the nonlinear Burgers' equation for an twelve-subdomain problem with randomly distributed interfaces.

  6. Numerical accuracy of mean-field calculations in coordinate space

    NASA Astrophysics Data System (ADS)

    Ryssens, W.; Heenen, P.-H.; Bender, M.

    2015-12-01

    Background: Mean-field methods based on an energy density functional (EDF) are powerful tools used to describe many properties of nuclei in the entirety of the nuclear chart. The accuracy required of energies for nuclear physics and astrophysics applications is of the order of 500 keV and much effort is undertaken to build EDFs that meet this requirement. Purpose: Mean-field calculations have to be accurate enough to preserve the accuracy of the EDF. We study this numerical accuracy in detail for a specific numerical choice of representation for mean-field equations that can accommodate any kind of symmetry breaking. Method: The method that we use is a particular implementation of three-dimensional mesh calculations. Its numerical accuracy is governed by three main factors: the size of the box in which the nucleus is confined, the way numerical derivatives are calculated, and the distance between the points on the mesh. Results: We examine the dependence of the results on these three factors for spherical doubly magic nuclei, neutron-rich 34Ne , the fission barrier of 240Pu , and isotopic chains around Z =50 . Conclusions: Mesh calculations offer the user extensive control over the numerical accuracy of the solution scheme. When appropriate choices for the numerical scheme are made the achievable accuracy is well below the model uncertainties of mean-field methods.

  7. Collective animal decisions: preference conflict and decision accuracy.

    PubMed

    Conradt, Larissa

    2013-12-06

    Social animals frequently share decisions that involve uncertainty and conflict. It has been suggested that conflict can enhance decision accuracy. In order to judge the practical relevance of such a suggestion, it is necessary to explore how general such findings are. Using a model, I examine whether conflicts between animals in a group with respect to preferences for avoiding false positives versus avoiding false negatives could, in principle, enhance the accuracy of collective decisions. I found that decision accuracy nearly always peaked when there was maximum conflict in groups in which individuals had different preferences. However, groups with no preferences were usually even more accurate. Furthermore, a relatively slight skew towards more animals with a preference for avoiding false negatives decreased the rate of expected false negatives versus false positives considerably (and vice versa), while resulting in only a small loss of decision accuracy. I conclude that in ecological situations in which decision accuracy is crucial for fitness and survival, animals cannot 'afford' preferences with respect to avoiding false positives versus false negatives. When decision accuracy is less crucial, animals might have such preferences. A slight skew in the number of animals with different preferences will result in the group avoiding that type of error more that the majority of group members prefers to avoid. The model also indicated that knowing the average success rate ('base rate') of a decision option can be very misleading, and that animals should ignore such base rates unless further information is available.

  8. The effect of upper extremity fatigue on grip strength and passing accuracy in junior basketball players.

    PubMed

    Ahmed, Taghread

    2013-01-01

    Fatigue is an unavoidable part of a basketball game, which may affect an athlete's performance. The aim of this study was to investigate the effect of upper extremity fatigue on grip strength and passing accuracy in basketball, and ascertain if the effects of different fatigue protocols on grip strength and passing accuracy are the same. Twenty-four juniors under 18 years old (age: 16.75 ± 0.62 years; body height: 184.5 ± 3.31 cm; body mass: 77.25 ± 3.22 kg) volunteered to participate in the study, and were divided into two groups. After a warm-up, both groups performed the basketball passing test and grip strength was recorded for each group under three different testing conditions: rest, 70% and 90% exercise intensity. The protocol used for the first group was the chest press, and for the second group the wrist curls. Results show that after the upper extremity fatigue protocol all parameters of the study (grip strength and passing accuracy) showed a significant decrease, and there was no significant difference between both groups regarding grip strength and passing accuracy. The study suggested that in order to avoid upper extremity fatigue, basketball trainers and coaches need to include upper extremity conditioning exercises into their training sessions.

  9. Statistical fitting accuracy in photon correlation spectroscopy

    NASA Technical Reports Server (NTRS)

    Shaumeyer, J. N.; Briggs, Matthew E.; Gammon, Robert W.

    1993-01-01

    Continuing our experimental investigation of the fitting accuracy associated with photon correlation spectroscopy, we collect 150 correlograms of light scattered at 90 deg from a thermostated sample of 91-nm-diameter, polystyrene latex spheres in water. The correlograms are taken with two correlators: one with linearly spaced channels and one with geometrically spaced channels. Decay rates are extracted from the single-exponential correlograms with both nonlinear least-squares fits and second-order cumulant fits. We make several statistical comparisons between the two fitting techniques and verify an earlier result that there is no sample-time dependence in the decay rate errors. We find, however, that the two fitting techniques give decay rates that differ by 1 percent.

  10. Quantitative code accuracy evaluation of ISP33

    SciTech Connect

    Kalli, H.; Miwrrin, A.; Purhonen, H.

    1995-09-01

    Aiming at quantifying code accuracy, a methodology based on the Fast Fourier Transform has been developed at the University of Pisa, Italy. The paper deals with a short presentation of the methodology and its application to pre-test and post-test calculations submitted to the International Standard Problem ISP33. This was a double-blind natural circulation exercise with a stepwise reduced primary coolant inventory, performed in PACTEL facility in Finland. PACTEL is a 1/305 volumetrically scaled, full-height simulator of the Russian type VVER-440 pressurized water reactor, with horizontal steam generators and loop seals in both cold and hot legs. Fifteen foreign organizations participated in ISP33, with 21 blind calculations and 20 post-test calculations, altogether 10 different thermal hydraulic codes and code versions were used. The results of the application of the methodology to nine selected measured quantities are summarized.

  11. Accuracy of lineaments mapping from space

    NASA Technical Reports Server (NTRS)

    Short, Nicholas M.

    1989-01-01

    The use of Landsat and other space imaging systems for lineaments detection is analyzed in terms of their effectiveness in recognizing and mapping fractures and faults, and the results of several studies providing a quantitative assessment of lineaments mapping accuracies are discussed. The cases under investigation include a Landsat image of the surface overlying a part of the Anadarko Basin of Oklahoma, the Landsat images and selected radar imagery of major lineaments systems distributed over much of Canadian Shield, and space imagery covering a part of the East African Rift in Kenya. It is demonstrated that space imagery can detect a significant portion of a region's fracture pattern, however, significant fractions of faults and fractures recorded on a field-produced geological map are missing from the imagery as it is evident in the Kenya case.

  12. ACCURACY LIMITATIONS IN LONG TRACE PROFILOMETRY.

    SciTech Connect

    TAKACS,P.Z.; QIAN,S.

    2003-08-25

    As requirements for surface slope error quality of grazing incidence optics approach the 100 nanoradian level, it is necessary to improve the performance of the measuring instruments to achieve accurate and repeatable results at this level. We have identified a number of internal error sources in the Long Trace Profiler (LTP) that affect measurement quality at this level. The LTP is sensitive to phase shifts produced within the millimeter diameter of the pencil beam probe by optical path irregularities with scale lengths of a fraction of a millimeter. We examine the effects of mirror surface ''macroroughness'' and internal glass homogeneity on the accuracy of the LTP through experiment and theoretical modeling. We will place limits on the allowable surface ''macroroughness'' and glass homogeneity required to achieve accurate measurements in the nanoradian range.

  13. Accuracy of maxillary positioning in bimaxillary surgery.

    PubMed

    Kretschmer, W B; Zoder, W; Baciut, G; Bacuit, Mihaela; Wangerin, K

    2009-09-01

    The aim of the study was to investigate the accuracy of a modified pin system for the vertical control of maxillary repositioning in bimaxillary osteotomies. The preoperative cephalograms of 239 consecutive patients who were to have bimaxillary osteotomies were superimposed on the postoperative films. Planned and observed vertical and horizontal movements of the upper incisor were analysed statistically. The mean deviations of -0.07 mm (95% confidence intervals (CIs) -0.17 to 0.04 mm) for the vertical movement and 0.12 mm (95% CI -0.06 to 0.30 mm) for the horizontal movement did not differ significantly from zero. Comparison of the two variances between intrusion and extrusion of the maxilla did not differ significantly either (p=0.51). These results suggest that the modified pin system for vertical control combined with interocclusal splints provides accurate vertical positioning of the anterior maxilla in orthognathic surgery.

  14. Methodology for high accuracy contact angle measurement.

    PubMed

    Kalantarian, A; David, R; Neumann, A W

    2009-12-15

    A new version of axisymmetric drop shape analysis (ADSA) called ADSA-NA (ADSA-no apex) was developed for measuring interfacial properties for drop configurations without an apex. ADSA-NA facilitates contact angle measurements on drops with a capillary protruding into the drop. Thus a much simpler experimental setup, not involving formation of a complete drop from below through a hole in the test surface, may be used. The contact angles of long-chained alkanes on a commercial fluoropolymer, Teflon AF 1600, were measured using the new method. A new numerical scheme was incorporated into the image processing to improve the location of the contact points of the liquid meniscus with the solid substrate to subpixel resolution. The images acquired in the experiments were also analyzed by a different drop shape technique called theoretical image fitting analysis-axisymmetric interfaces (TIFA-AI). The results were compared with literature values obtained by means of the standard ADSA for sessile drops with the apex. Comparison of the results from ADSA-NA with those from TIFA-AI and ADSA reveals that, with different numerical strategies and experimental setups, contact angles can be measured with an accuracy of less than 0.2 degrees. Contact angles and surface tensions measured from drops with no apex, i.e., by means of ADSA-NA and TIFA-AI, were considerably less scattered than those from complete drops with apex. ADSA-NA was also used to explore sources of improvement in contact angle resolution. It was found that using an accurate value of surface tension as an input enhances the accuracy of contact angle measurements.

  15. Improving the accuracy of death certification

    PubMed Central

    Myers, K A; Farquhar, D R

    1998-01-01

    BACKGROUND: Population-based mortality statistics are derived from the information recorded on death certificates. This information is used for many important purposes, such as the development of public health programs and the allocation of health care resources. Although most physicians are confronted with the task of completing death certificates, many do not receive adequate training in this skill. Resulting inaccuracies in information undermine the quality of the data derived from death certificates. METHODS: An educational intervention was designed and implemented to improve internal medicine residents' accuracy in death certificate completion. A total of 229 death certificates (146 completed before and 83 completed after the intervention) were audited for major and minor errors, and the rates of errors before and after the intervention were compared. RESULTS: Major errors were identified on 32.9% of the death certificates completed before the intervention, a rate comparable to previously reported rates for internal medicine services in teaching hospitals. Following the intervention the major error rate decreased to 15.7% (p = 0.01). The reduction in the major error rate was accounted for by significant reductions in the rate of listing of mechanism of death without a legitimate underlying cause of death (15.8% v. 4.8%) (p = 0.01) and the rate of improper sequencing of death certificate information (15.8% v. 6.0%) (p = 0.03). INTERPRETATION: Errors are common in the completion of death certificates in the inpatient teaching hospital setting. The accuracy of death certification can be improved with the implementation of a simple educational intervention. PMID:9614825

  16. Comparation of Typical Wetlands Classification Accuracy in Yellow River Estuary Using Multi-Angle Proba CHRIS Hyperspectral Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Wang, Xiaopeng; Zhang, Jie; Ma, Yi; Ren, Guangbo

    2013-01-01

    In this paper, Multi-angle PROBA CHRIS hyperspectral remote sensing images were used to study on their imaging quality and the ability of classification of Typical Wetlands in Yellow River Estuary, by the cooperation of interpretation and automatic classification. Taking 5-angle (0°, ±36°, ±55°) CHRIS hyperspectral remote sensing images of mode 2 obtained in September 2006 as an example, this paper research results indicate that the 0° image has the best imaging quality, with the highest spatial resolution, the ±36° images come second, the ±55° images are last; 5 typical wetlands, such as reservoir, bulrush, watercourse, barren beach and swamp were selected as study objects, then a Support Vector Machine (SVM) algorithm is used to classify different-angle remote sensing images into these 5 typical wetlands using training samples in the same location, the results of classification were analyzed based on field survey data, which shows that (1) The classification accuracy differs along the viewing angle of images, the overall accuracy and Kappa factor of the 0° image is highest, and the -36° image is lowest. (2) The overall accuracy and Kappa factor of the positive-angle images is higher than which of minus-angle images. (3) The producer accuracy and user accuracy of swamp is the lowest among all 5 typical wetlands in all images. (4) The producer accuracy and user accuracy of reservoir, bulrush and barren beach are relatively stable in all 5-angle images, however, the accuracies of Watercourse and swamp are fluctuant in all 5-angle images, and highest in the 0° image.

  17. Limits on the Accuracy of Linking. Research Report. ETS RR-10-22

    ERIC Educational Resources Information Center

    Haberman, Shelby J.

    2010-01-01

    Sampling errors limit the accuracy with which forms can be linked. Limitations on accuracy are especially important in testing programs in which a very large number of forms are employed. Standard inequalities in mathematical statistics may be used to establish lower bounds on the achievable inking accuracy. To illustrate results, a variety of…

  18. Stratified computed tomography findings improve diagnostic accuracy for appendicitis

    PubMed Central

    Park, Geon; Lee, Sang Chul; Choi, Byung-Jo; Kim, Say-June

    2014-01-01

    AIM: To improve the diagnostic accuracy in patients with symptoms and signs of appendicitis, but without confirmative computed tomography (CT) findings. METHODS: We retrospectively reviewed the database of 224 patients who had been operated on for the suspicion of appendicitis, but whose CT findings were negative or equivocal for appendicitis. The patient population was divided into two groups: a pathologically proven appendicitis group (n = 177) and a non-appendicitis group (n = 47). The CT images of these patients were re-evaluated according to the characteristic CT features as described in the literature. The re-evaluations and baseline characteristics of the two groups were compared. RESULTS: The two groups showed significant differences with respect to appendiceal diameter, and the presence of periappendiceal fat stranding and intraluminal air in the appendix. A larger proportion of patients in the appendicitis group showed distended appendices larger than 6.0 mm (66.3% vs 37.0%; P < 0.001), periappendiceal fat stranding (34.1% vs 8.9%; P = 0.001), and the absence of intraluminal air (67.6% vs 48.9%; P = 0.024) compared to the non-appendicitis group. Furthermore, the presence of two or more of these factors increased the odds ratio to 6.8 times higher than baseline (95%CI: 3.013-15.454; P < 0.001). CONCLUSION: Appendiceal diameter and wall thickening, fat stranding, and absence of intraluminal air can be used to increased diagnostic accuracy for appendicitis with equivocal CT findings. PMID:25320531

  19. RNA secondary structure modeling at consistent high accuracy using differential SHAPE.

    PubMed

    Rice, Greggory M; Leonard, Christopher W; Weeks, Kevin M

    2014-06-01

    RNA secondary structure modeling is a challenging problem, and recent successes have raised the standards for accuracy, consistency, and tractability. Large increases in accuracy have been achieved by including data on reactivity toward chemical probes: Incorporation of 1M7 SHAPE reactivity data into an mfold-class algorithm results in median accuracies for base pair prediction that exceed 90%. However, a few RNA structures are modeled with significantly lower accuracy. Here, we show that incorporating differential reactivities from the NMIA and 1M6 reagents--which detect noncanonical and tertiary interactions--into prediction algorithms results in highly accurate secondary structure models for RNAs that were previously shown to be difficult to model. For these RNAs, 93% of accepted canonical base pairs were recovered in SHAPE-directed models. Discrepancies between accepted and modeled structures were small and appear to reflect genuine structural differences. Three-reagent SHAPE-directed modeling scales concisely to structurally complex RNAs to resolve the in-solution secondary structure analysis problem for many classes of RNA.

  20. [Assessment of overall spatial accuracy in image guided stereotactic body radiotherapy using a spine registration method].

    PubMed

    Nakazawa, Hisato; Uchiyama, Yukio; Komori, Masataka; Hayashi, Naoki

    2014-06-01

    Stereotactic body radiotherapy (SBRT) for lung and liver tumors is always performed under image guidance, a technique used to confirm the accuracy of setup positioning by fusing planning digitally reconstructed radiographs with X-ray, fluoroscopic, or computed tomography (CT) images, using bony structures, tumor shadows, or metallic markers as landmarks. The Japanese SBRT guidelines state that bony spinal structures should be used as the main landmarks for patient setup. In this study, we used the Novalis system as a linear accelerator for SBRT of lung and liver tumors. The current study compared the differences between spine registration and target registration and calculated total spatial accuracy including setup uncertainty derived from our image registration results and the geometric uncertainty of the Novalis system. We were able to evaluate clearly whether overall spatial accuracy is achieved within a setup margin (SM) for planning target volume (PTV) in treatment planning. After being granted approval by the Hospital and University Ethics Committee, we retrospectively analyzed eleven patients with lung tumor and seven patients with liver tumor. The results showed the total spatial accuracy to be within a tolerable range for SM of treatment planning. We therefore regard our method to be suitable for image fusion involving 2-dimensional X-ray images during the treatment planning stage of SBRT for lung and liver tumors.

  1. High Accuracy Acquisition of 3-D Flight Trajectory of Individual Insect Based on Phase Measurement.

    PubMed

    Hu, Cheng; Deng, Yunkai; Wang, Rui; Liu, Changjiang; Long, Teng

    2016-12-17

    Accurate acquisition of 3-D flight trajectory of individual insect could be of benefit to the research of insect migration behaviors and the development of migratory entomology. This paper proposes a novel method to acquire 3-D flight trajectory of individual insect. First, based on the high range resolution synthesizing and the Doppler coherent processing, insects can be detected effectively, and the range resolution and velocity resolution are combined together to discriminate insects. Then, high accuracy range measurement with the carrier phase is proposed. The range measurement accuracy can reach millimeter level and benefits the acquisition of 3-D trajectory information significantly. Finally, based on the multi-baselines interferometry theory, the azimuth and elevation angles can be obtained with high accuracy. Simulation results prove that the retrieval accuracy of a simulated target's 3-D coordinates can reach centimeter level. Experiments utilizing S-band radar in an anechoic chamber were taken and results showed that the insects' flight behaviors and 3-D coordinates' variation matched the practical cases well. In conclusion, both the simulated and experimental datasets validate the feasibility of the proposed method, which could be a novel measurement way of monitoring flight trajectory of aerial free-fly insects.

  2. Accuracy and Reliability of Preoperative On-screen Templating Using Digital Radiographs for Total Hip Arthroplasty

    PubMed Central

    Shin, Jong Ki; Son, Seung Min; Kim, Tae Woo; Shin, Won Chul; Lee, Jung Sub

    2016-01-01

    Purpose Preoperative on-screen templating is a method of using acetate templates on digital images. The aim of the present study was to evaluate the accuracy, intra- and interobserver reliabilities of preoperative on-screen templating using digital radiographs for total hip arthroplasty (THA). Materials and Methods Two hundred patients with hip disease who were treated with primary cementless THA were retrospectively evaluated. The accuracy of on-screen templating was assessed by comparing the predicted prosthesis sizes with the actual sizes used operatively. The inter- and intraobserver reliabilities of the templating results were also evaluated. Results The prosthesis prediction accuracy within ±one size was 96.6% for the cup size and 97.8% for the stem size. The inter- and intraobserver reliabilities for the implant size were substantial (kappa>0.70). The intra- and interobserver reliabilities for the leg length discrepancy and femoral offset difference using the intraclass correlation coefficient ranged from 0.89 to 0.97. Conclusion Preoperative on-screen templating using digital radiographs showed substantial accuracy and reliability for implant prediction. It is an effective method for predicting the size of implant, correcting the leg length discrepancy and restoring the femoral offset. PMID:28097109

  3. High Accuracy Acquisition of 3-D Flight Trajectory of Individual Insect Based on Phase Measurement

    PubMed Central

    Hu, Cheng; Deng, Yunkai; Wang, Rui; Liu, Changjiang; Long, Teng

    2016-01-01

    Accurate acquisition of 3-D flight trajectory of individual insect could be of benefit to the research of insect migration behaviors and the development of migratory entomology. This paper proposes a novel method to acquire 3-D flight trajectory of individual insect. First, based on the high range resolution synthesizing and the Doppler coherent processing, insects can be detected effectively, and the range resolution and velocity resolution are combined together to discriminate insects. Then, high accuracy range measurement with the carrier phase is proposed. The range measurement accuracy can reach millimeter level and benefits the acquisition of 3-D trajectory information significantly. Finally, based on the multi-baselines interferometry theory, the azimuth and elevation angles can be obtained with high accuracy. Simulation results prove that the retrieval accuracy of a simulated target’s 3-D coordinates can reach centimeter level. Experiments utilizing S-band radar in an anechoic chamber were taken and results showed that the insects’ flight behaviors and 3-D coordinates’ variation matched the practical cases well. In conclusion, both the simulated and experimental datasets validate the feasibility of the proposed method, which could be a novel measurement way of monitoring flight trajectory of aerial free-fly insects. PMID:27999317

  4. Comparative analysis of Worldview-2 and Landsat 8 for coastal saltmarsh mapping accuracy assessment

    NASA Astrophysics Data System (ADS)

    Rasel, Sikdar M. M.; Chang, Hsing-Chung; Diti, Israt Jahan; Ralph, Tim; Saintilan, Neil

    2016-05-01

    Coastal saltmarsh and their constituent components and processes are of an interest scientifically due to their ecological function and services. However, heterogeneity and seasonal dynamic of the coastal wetland system makes it challenging to map saltmarshes with remotely sensed data. This study selected four important saltmarsh species Pragmitis australis, Sporobolus virginicus, Ficiona nodosa and Schoeloplectus sp. as well as a Mangrove and Pine tree species, Avecinia and Casuarina sp respectively. High Spatial Resolution Worldview-2 data and Coarse Spatial resolution Landsat 8 imagery were selected in this study. Among the selected vegetation types some patches ware fragmented and close to the spatial resolution of Worldview-2 data while and some patch were larger than the 30 meter resolution of Landsat 8 data. This study aims to test the effectiveness of different classifier for the imagery with various spatial and spectral resolutions. Three different classification algorithm, Maximum Likelihood Classifier (MLC), Support Vector Machine (SVM) and Artificial Neural Network (ANN) were tested and compared with their mapping accuracy of the results derived from both satellite imagery. For Worldview-2 data SVM was giving the higher overall accuracy (92.12%, kappa =0.90) followed by ANN (90.82%, Kappa 0.89) and MLC (90.55%, kappa = 0.88). For Landsat 8 data, MLC (82.04%) showed the highest classification accuracy comparing to SVM (77.31%) and ANN (75.23%). The producer accuracy of the classification results were also presented in the paper.

  5. Acquisition of decision making criteria: Reward rate ultimately beats accuracy

    PubMed Central

    Balci, Fuat; Simen, Patrick; Niyogi, Ritwik; Saxe, Andrew; Hughes, Jessica A.; Holmes, Philip; Cohen, Jonathan D.

    2012-01-01

    Speed-accuracy tradeoffs strongly influence the rate of reward that can be earned in many decision-making tasks. Previous reports suggest that human participants often adopt suboptimal speed-accuracy tradeoffs in single session, two-alternative forced-choice tasks. We investigated whether humans acquired optimal speed-accuracy tradeoffs when extensively trained with multiple signal qualities. When performance was characterized in terms of decision time and accuracy, our participants eventually performed nearly optimally in the case of higher signal qualities. Rather than adopting decision criteria that were individually optimal for each signal quality, participants adopted a single threshold that was nearly optimal for most signal qualities. However, setting a single threshold for different coherence conditions resulted in only negligible decrements in the maximum possible reward rate. Finally, we tested two hypotheses regarding the possible sources of suboptimal performance: a) favoring accuracy over reward rate and b) misestimating the reward rate due to timing uncertainty. Our findings provide support for both hypotheses, but also for the hypothesis that participants can learn to approach optimality. We find specifically that an accuracy bias dominates early performance, but diminishes greatly with practice. The residual discrepancy between optimal and observed performance can be explained by an adaptive response to uncertainty in time estimation. PMID:21264716

  6. Incorporating the effect of DEM resolution and accuracy for improved flood inundation mapping

    NASA Astrophysics Data System (ADS)

    Saksena, Siddharth; Merwade, Venkatesh

    2015-11-01

    Topography plays a major role in determining the accuracy of flood inundation areas. However, many areas in the United States and around the world do not have access to high quality topographic data in the form of Digital Elevation Models (DEM). For such areas, an improved understanding of the effects of DEM properties such as horizontal resolution and vertical accuracy on flood inundation maps may eventually lead to improved flood inundation modeling and mapping. This study attempts to relate the errors arising from DEM properties such as spatial resolution and vertical accuracy to flood inundation maps, and then use this relationship to create improved flood inundation maps from coarser resolution DEMs with low accuracy. The results from the five stream reaches used in this study show that water surface elevations (WSE) along the stream and the flood inundation area have a linear relationship with both DEM resolution and accuracy. This linear relationship is then used to extrapolate the water surface elevations from coarser resolution DEMs to get water surface elevations corresponding to a finer resolution DEM. Application of this approach show that improved results can be obtained from flood modeling by using coarser and less accurate DEMs, including public domain datasets such as the National Elevation Dataset and Shuttle Radar Topography Mission (SRTM) DEMs. The improvement in the WSE and its application to obtain better flood inundation maps is dependent on the study reach characteristics such as land use, valley shape, reach length and width. Application of the approach presented in this study on more reaches may lead to development of guidelines for flood inundation mapping using coarser resolution and less accurate topographic datasets.

  7. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions

    PubMed Central

    Murphy, Gillian; Greene, Ciara M.

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator), the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals. PMID:27625628

  8. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions.

    PubMed

    Murphy, Gillian; Greene, Ciara M

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator), the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals.

  9. Stereotype Accuracy: Toward Appreciating Group Differences.

    ERIC Educational Resources Information Center

    Lee, Yueh-Ting, Ed.; And Others

    The preponderance of scholarly theory and research on stereotypes assumes that they are bad and inaccurate, but understanding stereotype accuracy and inaccuracy is more interesting and complicated than simpleminded accusations of racism or sexism would seem to imply. The selections in this collection explore issues of the accuracy of stereotypes…

  10. [Upon scientific accuracy scheme at clinical specialties].

    PubMed

    Ortega Calvo, M

    2006-11-01

    Will be medical specialties like sciences in the future? Yes, progressively they will. Accuracy in clinical specialties will be dissimilar in the future because formal-logic mathematics, quantum physics advances and relativity theory utilities. Evidence based medicine is now helping to clinical specialties on scientific accuracy by the way of decision theory.

  11. Sound source localization identification accuracy: bandwidth dependencies.

    PubMed

    Yost, William A; Zhong, Xuan

    2014-11-01

    Sound source localization accuracy using a sound source identification task was measured in the front, right quarter of the azimuth plane as rms (root-mean-square) error (degrees) for stimulus conditions in which the bandwidth (1/20 to 2 octaves wide) and center frequency (250, 2000, 4000 Hz) of 200-ms noise bursts were varied. Tones of different frequencies (250, 2000, 4000 Hz) were also used. As stimulus bandwidth increases, there is an increase in sound source localization identification accuracy (i.e., rms error decreases). Wideband stimuli (>1 octave wide) produce best sound source localization accuracy (~6°-7° rms error), and localization accuracy for these wideband noise stimuli does not depend on center frequency. For narrow bandwidths (<1 octave) and tonal stimuli, accuracy does depend on center frequency such that highest accuracy is obtained for low-frequency stimuli (centered on 250 Hz), worse accuracy for mid-frequency stimuli (centered on 2000 Hz), and intermediate accuracy for high-frequency stimuli (centered on 4000 Hz).

  12. Accuracy of Parent Identification of Stuttering Occurrence

    ERIC Educational Resources Information Center

    Einarsdottir, Johanna; Ingham, Roger

    2009-01-01

    Background: Clinicians rely on parents to provide information regarding the onset and development of stuttering in their own children. The accuracy and reliability of their judgments of stuttering is therefore important and is not well researched. Aim: To investigate the accuracy of parent judgements of stuttering in their own children's speech…

  13. Increasing Deception Detection Accuracy with Strategic Questioning

    ERIC Educational Resources Information Center

    Levine, Timothy R.; Shaw, Allison; Shulman, Hillary C.

    2010-01-01

    One explanation for the finding of slightly above-chance accuracy in detecting deception experiments is limited variance in sender transparency. The current study sought to increase accuracy by increasing variance in sender transparency with strategic interrogative questioning. Participants (total N = 128) observed cheaters and noncheaters who…

  14. The Accuracy of Gender Stereotypes Regarding Occupations.

    ERIC Educational Resources Information Center

    Beyer, Sylvia; Finnegan, Andrea

    Given the salience of biological sex, it is not surprising that gender stereotypes are pervasive. To explore the prevalence of such stereotypes, the accuracy of gender stereotyping regarding occupations is presented in this paper. The paper opens with an overview of gender stereotype measures that use self-perceptions as benchmarks of accuracy,…

  15. Evaluating the accuracy of selenodesic reference grids

    NASA Technical Reports Server (NTRS)

    Koptev, A. A.

    1974-01-01

    Estimates were made of the accuracy of reference point grids using the technique of calculating the errors from theoretical analysis. Factors taken into consideration were: telescope accuracy, number of photographs, and libration amplitude. To solve the problem, formulas were used for the relationship between the coordinates of lunar surface points and their images on the photograph.

  16. Classification accuracy of actuarial risk assessment instruments.

    PubMed

    Neller, Daniel J; Frederick, Richard I

    2013-01-01

    Users of commonly employed actuarial risk assessment instruments (ARAIs) hope to generate numerical probability statements about risk; however, ARAI manuals often do not explicitly report data that are essential for understanding the classification accuracy of the instruments. In addition, ARAI manuals often contain data that have the potential for misinterpretation. The authors of the present article address the accurate generation of probability statements. First, they illustrate how the reporting of numerical probability statements based on proportions rather than predictive values can mislead users of ARAIs. Next, they report essential test characteristics that, to date, have gone largely unreported in ARAI manuals. Then they discuss a graphing method that can enhance the practice of clinicians who communicate risk via numerical probability statements. After the authors review several strategies for selecting optimal cut-off scores, they show how the graphing method can be used to estimate positive predictive values for each cut-off score of commonly used ARAIs, across all possible base rates. They also show how the graphing method can be used to estimate base rates of violent recidivism in local samples.

  17. Acute, intermediate intensity exercise, and speed and accuracy in working memory tasks: a meta-analytical comparison of effects.

    PubMed

    McMorris, Terry; Sproule, John; Turner, Anthony; Hale, Beverley J

    2011-03-01

    The purpose of this study was to compare, using meta-analytic techniques, the effect of acute, intermediate intensity exercise on the speed and accuracy of performance of working memory tasks. It was hypothesized that acute, intermediate intensity exercise would have a significant beneficial effect on response time and that effect sizes for response time and accuracy data would differ significantly. Random-effects meta-analysis showed a significant, beneficial effect size for response time, g=-1.41 (p<0.001) but a significant detrimental effect size, g=0.40 (p<0.01), for accuracy. There was a significant difference between effect sizes (Z(diff)=3.85, p<0.001). It was concluded that acute, intermediate intensity exercise has a strong beneficial effect on speed of response in working memory tasks but a low to moderate, detrimental one on accuracy. There was no support for a speed-accuracy trade-off. It was argued that exercise-induced increases in brain concentrations of catecholamines result in faster processing but increases in neural noise may negatively affect accuracy.

  18. Development of a laser synthetic wavelength interferometer for large displacement measurement with nanometer accuracy.

    PubMed

    Chen, Benyong; Yan, Liping; Yao, Xiguo; Yang, Tao; Li, Dacheng; Dong, Wenjun; Li, Chaorong; Tang, Weihua

    2010-02-01

    A laser synthetic wavelength interferometer that is capable of achieving large displacement measurement with nanometer accuracy is developed. The principle and the signal processing method of the interferometer are introduced. The displacement measurement experiments and the comparisons with a commercial interferometer both in small and large ranges are performed in order to verify the performance of the interferometer. Experimental results show that the average errors and standard deviations of the interferometer are in accordance with those obtained from the commercial interferometer. The resolution and the nonlinearity of the interferometer are also discussed in detail. These results show that the development of the interferometer is reasonable and feasible.

  19. Pairwise adaptive thermostats for improved accuracy and stability in dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Leimkuhler, Benedict; Shang, Xiaocheng

    2016-11-01

    We examine the formulation and numerical treatment of dissipative particle dynamics (DPD) and momentum-conserving molecular dynamics. We show that it is possible to improve both the accuracy and the stability of DPD by employing a pairwise adaptive Langevin thermostat that precisely matches the dynamical characteristics of DPD simulations (e.g., autocorrelation functions) while automatically correcting thermodynamic averages using a negative feedback loop. In the low friction regime, it is possible to replace DPD by a simpler momentum-conserving variant of the Nosé-Hoover-Langevin method based on thermostatting only pairwise interactions; we show that this method has an extra order of accuracy for an important class of observables (a superconvergence result), while also allowing larger timesteps than alternatives. All the methods mentioned in the article are easily implemented. Numerical experiments are performed in both equilibrium and nonequilibrium settings; using Lees-Edwards boundary conditions to induce shear flow.

  20. Power outage estimation for tropical cyclones: improved accuracy with simpler models.

    PubMed

    Nateghi, Roshanak; Guikema, Seth; Quiring, Steven M

    2014-06-01

    In this article, we discuss an outage-forecasting model that we have developed. This model uses very few input variables to estimate hurricane-induced outages prior to landfall with great predictive accuracy. We also show the results for a series of simpler models that use only publicly available data and can still estimate outages with reasonable accuracy. The intended users of these models are emergency response planners within power utilities and related government agencies. We developed our models based on the method of random forest, using data from a power distribution system serving two states in the Gulf Coast region of the United States. We also show that estimates of system reliability based on wind speed alone are not sufficient for adequately capturing the reliability of system components. We demonstrate that a multivariate approach can produce more accurate power outage predictions.

  1. Effects of gravity data quality and spacing on the accuracy of the geoid in South Korea

    NASA Astrophysics Data System (ADS)

    Hong, C.-K.; Kwon, J. H.; Lee, B. M.; Lee, J.; Choi, Y. S.; Lee, S.-B.

    2009-07-01

    The effects of gravity data quality and spacing on the accuracy of the computed geoid are analyzed. The analysis is performed using simulated gravity data that accommodate the real gravity signal in South Korea. The reference geoid is generated using both simulated gravity data and digital terrain models (DTM), assuming that both data sets are errorless. By artificially controlling the gravity data quality and spacing, we are able to calculate and analyze the geoid errors. The results show that the current distribution of real gravity data in South Korea causes geoid errors, with the standard deviation being as much as 8 cm, and that these geoid errors are mainly caused by the distribution of gravity data rather than by the noise in the data. Areas showing large geoid errors are also clearly identified; these areas should be subjected to supplementary gravity surveying at data spacing smaller than 2 km to achieve a 5-cm level of geoid accuracy.

  2. Mercury's Core Molten, Radar Study Shows

    NASA Astrophysics Data System (ADS)

    2007-05-01

    Scientists using a high-precision planetary radar technique for the first time have discovered that the innermost planet Mercury probably has a molten core, resolving a mystery of more than three decades. The discovery, which used the National Science Foundation's Robert C. Byrd Green Bank Telescope in West Virginia and Arecibo Observatory in Puerto Rico, and NASA/Jet Propulsion Laboratory antennas in California, is an important step toward a better understanding of how planets form and evolve. Planetary Radar High-precision planetary radar technique sent signal to Mercury, received reflection. CREDIT: Bill Saxton, NRAO/AUI/NSF Click on image for high-resolution file (447 KB) "For a long time it was thought we'd have to land spacecraft on Mercury to learn if its core is solid or molten. Now we've answered that question using ground-based telescopes," said Jean-Luc Margot, of Cornell University, leader of the research team, which published its results in the May 4 issue of the journal Science. Mercury is one of the least-understood of the planets in our Solar System. Its distance from the Sun is just over one-third that of the Earth, and it contains a mass just 5½ percent that of Earth. Only about half of Mercury's surface has been photographed by a spacecraft, Mariner 10, back in 1974. Mariner 10 also discovered that Mercury has a weak magnetic field, about one percent as strong as Earth's. That discovery spurred a scientific debate about the planet's core. Scientists normally expect a rocky planet's magnetic field to be caused by an electromagnetic dynamo in a molten core. However, Mercury is so small that most scientists expected its core to have cooled and solidified long ago. Those scientists speculated that the magnetic field seen today may have been "frozen" into the planet when the core cooled. "Whether the core is molten or solid today depends greatly on the chemical composition of the core. That chemical composition can provide important clues about the

  3. The influence of the cavity preparation design on marginal accuracy of laboratory-processed resin composite restorations.

    PubMed

    Fonseca, Rodrigo Borges; Correr-Sobrinho, Lourenço; Fernandes-Neto, Alfredo Júlio; Quagliatto, Paulo Sérgio; Soares, Carlos José

    2008-03-01

    The aim of this study was to evaluate the influence of different cavity preparation designs on marginal accuracy of laboratory-processed resin composite restored teeth. Eighty mandibular human third molars were selected. There were two experimental factors, occlusal isthmus width (narrow vs wide) and cuspal coverage (inlay, one-cusp onlay, two-cusp onlay, and all-cusp onlay), resulting on eight groups (N = 10). Indirect composite restorations (SR Adoro, Ivoclar-Vivadent) were manufactured and positioned over each respective preparation. Marginal accuracy evaluation was accomplished using a stereomicroscope at three points on buccal, lingual, mesial, and distal regions with 40x magnification. The results showed significant differences (P = 0.00) with wide inlay showing the best overall marginal accuracy and narrow inlay the worst one. Two-way analysis of variance (ANOVA) showed significant differences when considering the factor occlusal isthmus width (P = 0.00). In general, preparations with wide occlusal isthmus presented better results than narrow ones, except for wide all-cusp onlays; however, the test failed to show differences when considering the cuspal coverage (P = 0.42) or the interaction between both factors (P = 0.30). The effect of occlusal width extension on marginal accuracy of indirect composite resin restorations is significant, with lower values of gaps width in wide preparations, but since in a clinical situation this would mean greater removal of sound tooth structure, less-aggressive preparations combined with other restorative procedures seem to be more feasible.

  4. Influence of spatial temperature distribution on high accuracy interferometric metrology

    NASA Astrophysics Data System (ADS)

    Gu, Yongqiang; Miao, Erlong; Yan, Feng; Zhang, Jian; Yang, Huaijiang

    2010-10-01

    We calculate the influence of temperature change on the refractive index of air, establish a model of air temperature distribution and analyze the effect of different temperature distribution on the high accuracy interferometric metrology. First, a revised Edlen formula is employed to acquire the relation between temperature and refractive index of air, followed by introducing the fixed temperature gradient distribution among the spatial grid within the optical cavity between the reference flat and the test flat of the Fizeau interferometer, accompanied by a temperature change random function within each grid. Finally, all the rays through the air layer with different incident angles are traced by Matlab program in order to obtain the final output position, angle and OPD for each ray. The influence of different temperature distribution and the length of the optical cavity in on the testing accuracy can be analyzed through the RMS value that results from repeatable rays tracing. As a result, the horizontal distribution (vertical to optical axis) has a large effect on the testing accuracy. Thus, to realize the high accuracy figure metrology, the horizontal distribution of temperature must be rigorously controlled as well as to shorten the length of the optical cavity to a large extent. The results from our simulation are of great significant for the accuracy analysis of interferometric testing and the research of manufacturing a interferometer.

  5. Novel Resistance Measurement Method: Analysis of Accuracy and Thermal Dependence with Applications in Fiber Materials.

    PubMed

    Casans, Silvia; Rosado-Muñoz, Alfredo; Iakymchuk, Taras

    2016-12-14

    Material resistance is important since different physicochemical properties can be extracted from it. This work describes a novel resistance measurement method valid for a wide range of resistance values up to 100 GΩ at a low powered, small sized, digitally controlled and wireless communicated device. The analog and digital circuits of the design are described, analysing the main error sources affecting the accuracy. Accuracy and extended uncertainty are obtained for a pattern decade box, showing a maximum of 1 % accuracy for temperatures below 30 ∘ C in the range from 1 MΩ to 100 GΩ. Thermal analysis showed stability up to 50 ∘ C for values below 10 GΩ and systematic deviations for higher values. Power supply V i applied to the measurement probes is also analysed, showing no differences in case of the pattern decade box, except for resistance values above 10 GΩ and temperatures above 35 ∘ C. To evaluate the circuit behaviour under fiber materials, an 11-day drying process in timber from four species (Oregon pine-Pseudotsuga menziesii, cedar-Cedrus atlantica, ash-Fraxinus excelsior, chestnut-Castanea sativa) was monitored. Results show that the circuit, as expected, provides different resistance values (they need individual conversion curves) for different species and the same ambient conditions. Additionally, it was found that, contrary to the decade box analysis, V i affects the resistance value due to material properties. In summary, the proposed circuit is able to accurately measure material resistance that can be further related to material properties.

  6. Novel Resistance Measurement Method: Analysis of Accuracy and Thermal Dependence with Applications in Fiber Materials

    PubMed Central

    Casans, Silvia; Rosado-Muñoz, Alfredo; Iakymchuk, Taras

    2016-01-01

    Material resistance is important since different physicochemical properties can be extracted from it. This work describes a novel resistance measurement method valid for a wide range of resistance values up to 100 GΩ at a low powered, small sized, digitally controlled and wireless communicated device. The analog and digital circuits of the design are described, analysing the main error sources affecting the accuracy. Accuracy and extended uncertainty are obtained for a pattern decade box, showing a maximum of 1% accuracy for temperatures below 30 ∘C in the range from 1 MΩ to 100 GΩ. Thermal analysis showed stability up to 50 ∘C for values below 10 GΩ and systematic deviations for higher values. Power supply Vi applied to the measurement probes is also analysed, showing no differences in case of the pattern decade box, except for resistance values above 10 GΩ and temperatures above 35 ∘C. To evaluate the circuit behaviour under fiber materials, an 11-day drying process in timber from four species (Oregon pine-Pseudotsuga menziesii, cedar-Cedrus atlantica, ash-Fraxinus excelsior, chestnut-Castanea sativa) was monitored. Results show that the circuit, as expected, provides different resistance values (they need individual conversion curves) for different species and the same ambient conditions. Additionally, it was found that, contrary to the decade box analysis, Vi affects the resistance value due to material properties. In summary, the proposed circuit is able to accurately measure material resistance that can be further related to material properties. PMID:27983652

  7. A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

    NASA Astrophysics Data System (ADS)

    Malinowski, Marcin; Kwiecień, Janusz

    2016-12-01

    Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

  8. Evaluation of precision and accuracy assessment of different 3-D surface imaging systems for biomedical purposes.

    PubMed

    Eder, Maximilian; Brockmann, Gernot; Zimmermann, Alexander; Papadopoulos, Moschos A; Schwenzer-Zimmerer, Katja; Zeilhofer, Hans Florian; Sader, Robert; Papadopulos, Nikolaos A; Kovacs, Laszlo

    2013-04-01

    Three-dimensional (3-D) surface imaging has gained clinical acceptance, especially in the field of cranio-maxillo-facial and plastic, reconstructive, and aesthetic surgery. Six scanners based on different scanning principles (Minolta Vivid 910®, Polhemus FastSCAN™, GFM PRIMOS®, GFM TopoCAM®, Steinbichler Comet® Vario Zoom 250, 3dMD DSP 400®) were used to measure five sheep skulls of different sizes. In three areas with varying anatomical complexity (areas, 1 = high; 2 = moderate; 3 = low), 56 distances between 20 landmarks are defined on each skull. Manual measurement (MM), coordinate machine measurements (CMM) and computer tomography (CT) measurements were used to define a reference method for further precision and accuracy evaluation of different 3-D scanning systems. MM showed high correlation to CMM and CT measurements (both r = 0.987; p < 0.001) and served as the reference method. TopoCAM®, Comet® and Vivid 910® showed highest measurement precision over all areas of complexity; Vivid 910®, the Comet® and the DSP 400® demonstrated highest accuracy over all areas with Vivid 910® being most accurate in areas 1 and 3, and the DSP 400® most accurate in area 2. In accordance to the measured distance length, most 3-D devices present higher measurement precision and accuracy for large distances and lower degrees of precision and accuracy for short distances. In general, higher degrees of complexity are associated with lower 3-D assessment accuracy, suggesting that for optimal results, different types of scanners should be applied to specific clinical applications and medical problems according to their special construction designs and characteristics.

  9. Pedicle screw placement accuracy of bone-mounted miniature robot system.

    PubMed

    Tsai, Tai-Hsin; Tzou, Rong-Dar; Su, Yu-Feng; Wu, Chieh-Hsin; Tsai, Cheng-Yu; Lin, Chih-Lung

    2017-01-01

    This article describes factors affecting the accuracy of transpedicle screw placements performed with the Renaissance robot-guided system and reviews the relevant literature. Between January 2013 and January 2015, Renaissance robot-guided spinal surgery was performed in 125 patients at Kaohsiung Medical University Hospital in Kaohsiung, Taiwan. The surgeries included 662 transpedicle screw implants and 49 Kirschner wire (K-wire) reimplants performed by intraoperative repositioning. The lead author evaluated the accuracy of all K-wire insertions and classified their accuracy into 3 categories relative to the preoperative plan for transpedicle screw placement. For cases in which screws required repositioning after the registration step, factors affecting pedicle screw placement were determined according to the consensus of 3 experienced spinal surgeons. According to the scheme developed by Kuo et al (PLoS One 2016;11:e0153235), the K-wire placement accuracies before and after repositioning were respectively classified as follows: 76.1% and 77.6% in type I; 12.2% and 17.7% in type IIa; 4.3% and 4.5% in type IIb; 6.4% and 0% in type IIIa; and 1% and 1% in type IIIb. The percentage of screws requiring repositioning due to drilling error was 85.7% (42/49). Comparisons of preoperative and postoperative function showed significantly improved accuracy. This study showed that inaccurate pedicle screw placement mainly results from errors in preoperative planning, mounting, registration, drilling, and robot assembly. Pedicle screw placement using a bone-mounted miniature robot system requires meticulous preoperative planning to minimize these errors.

  10. Pedicle screw placement accuracy of bone-mounted miniature robot system

    PubMed Central

    Tsai, Tai-Hsin; Tzou, Rong-Dar; Su, Yu-Feng; Wu, Chieh-Hsin; Tsai, Cheng-Yu; Lin, Chih-Lung

    2017-01-01

    Abstract This article describes factors affecting the accuracy of transpedicle screw placements performed with the Renaissance robot-guided system and reviews the relevant literature. Between January 2013 and January 2015, Renaissance robot-guided spinal surgery was performed in 125 patients at Kaohsiung Medical University Hospital in Kaohsiung, Taiwan. The surgeries included 662 transpedicle screw implants and 49 Kirschner wire (K-wire) reimplants performed by intraoperative repositioning. The lead author evaluated the accuracy of all K-wire insertions and classified their accuracy into 3 categories relative to the preoperative plan for transpedicle screw placement. For cases in which screws required repositioning after the registration step, factors affecting pedicle screw placement were determined according to the consensus of 3 experienced spinal surgeons. According to the scheme developed by Kuo et al (PLoS One 2016;11:e0153235), the K-wire placement accuracies before and after repositioning were respectively classified as follows: 76.1% and 77.6% in type I; 12.2% and 17.7% in type IIa; 4.3% and 4.5% in type IIb; 6.4% and 0% in type IIIa; and 1% and 1% in type IIIb. The percentage of screws requiring repositioning due to drilling error was 85.7% (42/49). Comparisons of preoperative and postoperative function showed significantly improved accuracy. This study showed that inaccurate pedicle screw placement mainly results from errors in preoperative planning, mounting, registration, drilling, and robot assembly. Pedicle screw placement using a bone-mounted miniature robot system requires meticulous preoperative planning to minimize these errors. PMID:28099339

  11. The accuracy of large-area forest canopy cover estimation using Landsat in boreal region

    NASA Astrophysics Data System (ADS)

    Hadi; Korhonen, Lauri; Hovi, Aarne; Rönnholm, Petri; Rautiainen, Miina

    2016-12-01

    Large area prediction of continuous field of tree cover i.e., canopy cover (CC) using Earth observation data is of high interest in practical forestry, ecology, and climate change mitigation activities. We report the accuracy of using Landsat images for CC prediction in boreal forests validated with field reference plots (N = 250) covering large variation in latitude, forest structure, species composition, and site type. We tested two statistical models suitable for estimating CC: the beta regression (BetaReg) and random forest (RanFor). Landsat-based predictors utilized include individual bands, spectral vegetation indices (SVI), and Tasseled cap (Tass) features. Additionally, we tested an alternative model based on spectral mixture analysis (SMA). Finally, we carried out a first validation in boreal forests of the recently published Landsat Tree Cover Continuous (TCC) global product. Results showed simple BetaReg with red band reflectance provided the highest prediction accuracy (leave-site-out RMSECV 13.7%; R2CV 0.59; biasCV 0.5%). Spectral transformations into SVI and Tass did not improve accuracy. Including additional predictors did not significantly improve accuracy either. Nonlinear model RanFor did not outperform BetaReg. The alternative SMA model did not outperform the empirical models. However, empirical models cannot resolve the underestimation of high cover and overestimation of low cover. SMA prediction errors appeared less dependent on forest structure, while there seemed to be a potential for improvement by accounting for endmember variability of different tree species. Finally, using temporally concurrent observations, we showed the reasonably good accuracy of Landsat TCC product in boreal forests (RMSE 13.0%; R2 0.53; bias -2.1%), however with a tendency to underestimate high cover.

  12. Geolocation and Pointing Accuracy Analysis for the WindSat Sensor

    NASA Technical Reports Server (NTRS)

    Meissner, Thomas; Wentz, Frank J.; Purdy, William E.; Gaiser, Peter W.; Poe, Gene; Uliana, Enzo A.

    2006-01-01

    Geolocation and pointing accuracy analyses of the WindSat flight data are presented. The two topics were intertwined in the flight data analysis and will be addressed together. WindSat has no unusual geolocation requirements relative to other sensors, but its beam pointing knowledge accuracy is especially critical to support accurate polarimetric radiometry. Pointing accuracy was improved and verified using geolocation analysis in conjunction with scan bias analysis. nvo methods were needed to properly identify and differentiate between data time tagging and pointing knowledge errors. Matchups comparing coastlines indicated in imagery data with their known geographic locations were used to identify geolocation errors. These coastline matchups showed possible pointing errors with ambiguities as to the true source of the errors. Scan bias analysis of U, the third Stokes parameter, and of vertical and horizontal polarizations provided measurement of pointing offsets resolving ambiguities in the coastline matchup analysis. Several geolocation and pointing bias sources were incfementally eliminated resulting in pointing knowledge and geolocation accuracy that met all design requirements.

  13. Emotion perception accuracy and bias in face-to-face versus cyberbullying.

    PubMed

    Ciucci, Enrica; Baroncelli, Andrea; Nowicki, Stephen

    2014-01-01

    The authors investigated the association of traditional and cyber forms of bullying and victimization with emotion perception accuracy and emotion perception bias. Four basic emotions were considered (i.e., happiness, sadness, anger, and fear); 526 middle school students (280 females; M age = 12.58 years, SD = 1.16 years) were recruited, and emotionality was controlled. Results indicated no significant findings for girls. Boys with higher levels of traditional bullying did not show any deficit in perception accuracy of emotions, but they were prone to identify happiness and fear in faces when a different emotion was expressed; in addition, male cyberbullying was related to greater accuracy in recognizing fear. In terms of the victims, cyber victims had a global problem in recognizing emotions and a specific problem in processing anger and fear. It was concluded that emotion perception accuracy and bias were associated with bullying and victimization for boys not only in traditional settings but also in the electronic ones. Implications of these findings for possible intervention are discussed.

  14. Assembly accuracy analysis for small components with a planar surface in large-scale metrology

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Huang, Peng; Li, Jiangxiong; Ke, Yinglin; Yang, Bingru; Maropoulos, Paul G.

    2016-04-01

    Large-scale mechanical products, such as aircraft and rockets, consist of large numbers of small components, which introduce additional difficulty for assembly accuracy and error estimation. Planar surfaces as key product characteristics are usually utilised for positioning small components in the assembly process. This paper focuses on assembly accuracy analysis of small components with planar surfaces in large-scale volume products. To evaluate the accuracy of the assembly system, an error propagation model for measurement error and fixture error is proposed, based on the assumption that all errors are normally distributed. In this model, the general coordinate vector is adopted to represent the position of the components. The error transmission functions are simplified into a linear model, and the coordinates of the reference points are composed by theoretical value and random error. The installation of a Head-Up Display is taken as an example to analyse the assembly error of small components based on the propagation model. The result shows that the final coordination accuracy is mainly determined by measurement error of the planar surface in small components. To reduce the uncertainty of the plane measurement, an evaluation index of measurement strategy is presented. This index reflects the distribution of the sampling point set and can be calculated by an inertia moment matrix. Finally, a practical application is introduced for validating the evaluation index.

  15. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    PubMed Central

    Islam, Md. Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  16. The accuracy of femoral intramedullary guides in total knee arthroplasty.

    PubMed

    Reed, S C; Gollish, J

    1997-09-01

    Of the technical factors important in achieving a successful total knee arthroplasty, limb alignment has been demonstrated to be most influential in determining implant survival. Intramedullary femoral guide systems rely on placement of the intramedullary rod along the anatomic axis of the femur. In this article, the accuracy of the femoral intramedullary guide is investigated using radiographs and a mathematical model. The femoral anatomic axis was drawn on 40 consecutive, preoperative, 3-ft standing radiographs. Using a mathematical model, the potential angular error in the distal femoral cut from aberrant placement of the intramedullary rod was estimated. Calculated values correlated with measured values from plain radiographs and an intramedullary guide template. The anatomic axis was found to exit the distal femur at an average of 6.6 mm medial to the center of the femoral notch. Substantial malalignment error resulted from minor malposition of the intramedullary rod. Most books and diagrams demonstrating the use of intramedullary guides indicate that the entry point is at the center of the femoral notch. These results show that the true entry point is medial to the center of the notch, and rod placement error results in excessive valgus alignment. Preoperative drawing of the anatomic axis on a 3-ft or 18-inch anteroposterior radiograph is recommended. The results both demonstrate the importance of correct use of the guide and heighten cognizance among surgeons performing total knee arthroplasty as to the limitations of the intramedullary guides.

  17. Ozone absorption coefficients' role in Dobson instrument ozone measurement accuracy

    NASA Astrophysics Data System (ADS)

    Basher, R. E.

    1982-11-01

    The differences of 10% or more between the laboratory measurements of UV absorption coefficients by different investigators indicate accuracies that are quite inadequate for current needs in the measurement of atmospheric ozone. The standard band-integrated set of coefficients now used with the Dobson instrument are mutually consistent to about 2%, but their absolute accuracy is still in question. The accurate calculation of band-integrated coefficients must take account of their dependence on source spectral irradiance, atmospheric spectral transmittance, mean ozone temperature, and instrument spectral transmittance. A careful examination shows that Komhyr's (1980) case for an error of about +5% in the standard Dobson AD ozone estimation is subject to large uncertainties and certain lacks of independence. The obvious solution to this accuracy problem lies in better laboratory measurements of ozone absorption.

  18. New Reconstruction Accuracy Metric for 3D PIV

    NASA Astrophysics Data System (ADS)

    Bajpayee, Abhishek; Techet, Alexandra

    2015-11-01

    Reconstruction for 3D PIV typically relies on recombining images captured from different viewpoints via multiple cameras/apertures. Ideally, the quality of reconstruction dictates the accuracy of the derived velocity field. A reconstruction quality parameter Q is commonly used as a measure of the accuracy of reconstruction algorithms. By definition, a high Q value requires intensity peak levels and shapes in the reconstructed and reference volumes to be matched. We show that accurate velocity fields rely only on the peak locations in the volumes and not on intensity peak levels and shapes. In synthetic aperture (SA) PIV reconstructions, the intensity peak shapes and heights vary with the number of cameras and due to spatial/temporal particle intensity variation respectively. This lowers Q but not the accuracy of the derived velocity field. We introduce a new velocity vector correlation factor Qv as a metric to assess the accuracy of 3D PIV techniques, which provides a better indication of algorithm accuracy. For SAPIV, the number of cameras required for a high Qv are lower than that for a high Q. We discuss Qv in the context of 3D PIV and also present a preliminary comparison of the performance of TomoPIV and SAPIV based on Qv.

  19. Analysis on accuracy improvement of rotor-stator rubbing localization based on acoustic emission beamforming method.

    PubMed

    He, Tian; Xiao, Denghong; Pan, Qiang; Liu, Xiandong; Shan, Yingchun

    2014-01-01

    This paper attempts to introduce an improved acoustic emission (AE) beamforming method to localize rotor-stator rubbing fault in rotating machinery. To investigate the propagation characteristics of acoustic emission signals in casing shell plate of rotating machinery, the plate wave theory is used in a thin plate. A simulation is conducted and its result shows the localization accuracy of beamforming depends on multi-mode, dispersion, velocity and array dimension. In order to reduce the effect of propagation characteristics on the source localization, an AE signal pre-process method is introduced by combining plate wave theory and wavelet packet transform. And the revised localization velocity to reduce effect of array size is presented. The accuracy of rubbing localization based on beamforming and the improved method of present paper are compared by the rubbing test carried on a test table of rotating machinery. The results indicate that the improved method can localize rub fault effectively.

  20. The Social Accuracy Model of Interpersonal Perception: Assessing Individual Differences in Perceptive and Expressive Accuracy

    ERIC Educational Resources Information Center

    Biesanz, Jeremy C.

    2010-01-01

    The social accuracy model of interpersonal perception (SAM) is a componential model that estimates perceiver and target effects of different components of accuracy across traits simultaneously. For instance, Jane may be generally accurate in her perceptions of others and thus high in "perceptive accuracy"--the extent to which a particular…

  1. Evaluating arguments during instigations of defence motivation and accuracy motivation.

    PubMed

    Liu, Cheng-Hong

    2017-05-01

    When people evaluate the strength of an argument, their motivations are likely to influence the evaluation. However, few studies have specifically investigated the influences of motivational factors on argument evaluation. This study examined the effects of defence and accuracy motivations on argument evaluation. According to the compatibility between the advocated positions of arguments and participants' prior beliefs and the objective strength of arguments, participants evaluated four types of arguments: compatible-strong, compatible-weak, incompatible-strong, and incompatible-weak arguments. Experiment 1 revealed that participants possessing a high defence motivation rated compatible-weak arguments as stronger and incompatible-strong ones as weaker than participants possessing a low defence motivation. However, the strength ratings between the high and low defence groups regarding both compatible-strong and incompatible-weak arguments were similar. Experiment 2 revealed that when participants possessed a high accuracy motivation, they rated compatible-weak arguments as weaker and incompatible-strong ones as stronger than when they possessed a low accuracy motivation. However, participants' ratings on both compatible-strong and incompatible-weak arguments were similar when comparing high and low accuracy conditions. The results suggest that defence and accuracy motivations are two major motives influencing argument evaluation. However, they primarily influence the evaluation results for compatible-weak and incompatible-strong arguments, but not for compatible-strong and incompatible-weak arguments.

  2. Stochastic FDTD accuracy improvement through correlation coefficient estimation

    NASA Astrophysics Data System (ADS)

    Masumnia Bisheh, Khadijeh; Zakeri Gatabi, Bijan; Andargoli, Seyed Mehdi Hosseini

    2015-04-01

    This paper introduces a new scheme to improve the accuracy of the stochastic finite difference time domain (S-FDTD) method. S-FDTD, reported recently by Smith and Furse, calculates the variations in the electromagnetic fields caused by variability or uncertainty in the electrical properties of the materials in the model. The accuracy of the S-FDTD method is controlled by the approximations for correlation coefficients between the electrical properties of the materials in the model and the fields propagating in them. In this paper, new approximations for these correlation coefficients are obtained using Monte Carlo method with a small number of runs, terming them as Monte Carlo correlation coefficients (MC-CC). Numerical results for two bioelectromagnetic simulation examples demonstrate that MC-CC can improve the accuracy of the S-FDTD method and yield more accurate results than previous approximations.

  3. Theoretical informational estimation of spatial signal restoration accuracy

    NASA Astrophysics Data System (ADS)

    Shultz, Sergey V.; Bakut, Peter A.; Shumilov, Yurij P.

    1994-12-01

    In the article the relationship between the accuracy of random spatial signal restoration and information quantity about signal, that is inherent in the random observing function, is considered on the base of information and statistical decision theory notions. It is shown that in special case of statistically homogeneous strong correlated signal in the observing area the obtained lower bound of signal restoration error dispersion is analogous to the lower bound defined with Cramer-Rao inequality which is widely used in statistical estimation theory for analysing of the discrete parameters potential accu- racy. The obtained results are used for accuracy analysis of satellite information systems which are employed in the optical wavelength region. The image restoration accuracy is considered in dependence of the influence of small particles ejected from satellite and the quantum noise being, the result of irradiance-photodetector substance interaction.

  4. Accuracy of Small Base Metal Dental Castings,

    DTIC Science & Technology

    1980-07-10

    aCCURACY OF SMALL BASE METAL DENTAL CASTINGS,(U) M JUL 80 E A HUBET, S 6 VERMILYEA, M .J KUFFLER UNCLASSIFIED NE7 hhhhh *EN UN~CLASSIFIED SECURITY...TPCCSI70NO. 3. RECIPIENT’S .CATALOG NUMBER I _% dSutte 5. TYPE OF REPORT & PERIOD COVERED Accuracy of Small Base Metal Dental Castings Manuscript S...base metal- alloys is countered by their inadequate casting accuracy . Until this problem can be overcome, the acceptance of such alloys for routine use

  5. Discrimination in measures of knowledge monitoring accuracy

    PubMed Central

    Was, Christopher A.

    2014-01-01

    Knowledge monitoring predicts academic outcomes in many contexts. However, measures of knowledge monitoring accuracy are often incomplete. In the current study, a measure of students’ ability to discriminate known from unknown information as a component of knowledge monitoring was considered. Undergraduate students’ knowledge monitoring accuracy was assessed and used to predict final exam scores in a specific course. It was found that gamma, a measure commonly used as the measure of knowledge monitoring accuracy, accounted for a small, but significant amount of variance in academic performance whereas the discrimination and bias indexes combined to account for a greater amount of variance in academic performance. PMID:25339979

  6. Practicality and accuracy of prehospital rapid venous blood glucose determination.

    PubMed

    Holstein, A; Kühne, D; Elsing, H G; Thiessen, E; Plaschke, A; Widjaja, A; Vogel, M Y; Egberts, E H

    2000-10-01

    Blood glucose testing plays an important role in emergency medicine. Although the use of visual reagent test strips is widely established in this setting, the accuracy of reflectometric blood glucose determinations under emergency conditions has rarely been investigated. In a prospective study, 522 of a total of 3,217 patients undergoing emergency blood glucose testing had parallel blood glucose measurements performed using a specific enzymatic method. These 522 patients (aged 61.4 years, 54% men, 90 cases of severe hypoglycemia) had an intravenous access placed at the scene of the emergency. Venous whole blood from the introducer needle of the access was applied to the test strip and the glucose measured with a GlucoTouch reflectometer (LifeScan, Inc.). A blood sample from the intravenous access was then immediately collected in a monovette for subsequent glucose determination in a chemical laboratory (hexokinase method) within 20 to 40 minutes. The emergency glucose measurements (mean: 7.3 mmol/L [95% confidence interval [CI] 6.9 to 7.7]; range: 0.55 to 27.7) correlated well with the reference laboratory results (Pearson's r = .98; linear regression analysis: slope 1.0, axial intercept 1.74). Error grid analysis also showed good agreement between corresponding measurements: zone A 96.7%, B 2.5%, C 0% and D 0.8%. The mean difference using the Bland-Altman method was 0.14 mmoVL; 2 SD 1.8 mmol/L; minimum -7.0 mmol/L; maximum 4.4 mmol/L. The accuracy of the rapid venous blood glucose determination by constantly changing emergency teams was high. Especially in 90 hypoglycemic patients, there were no deviations from the reference method that could have led to clinically relevant wrong decisions. The method of collecting whole blood directly from the venous access is simple and robust, and is independent of the hemodynamic status of the patient.

  7. Diagnostic accuracy of the bronchodilator response in children

    PubMed Central

    Tse, Sze Man; Gold, Diane R.; Sordillo, Joanne E.; Hoffman, Elaine B.; Gillman, Matthew W.; Rifas-Shiman, Sheryl L.; Fuhlbrigge, Anne L.; Tantisira, Kelan G.; Weiss, Scott T.; Litonjua, Augusto A.

    2013-01-01

    Background The bronchodilator response (BDR) reflects the reversibility of airflow obstruction and is recommended as an adjunctive test to diagnose asthma. The validity of the commonly used definition of BDR, a 12% or greater change in FEV1 from baseline, has been questioned in childhood. Objectives We sought to examine the diagnostic accuracy of the BDR test by using 3 large pediatric cohorts. Methods Cases include 1041 children with mild-to-moderate asthma from the Childhood Asthma Management Program. Control subjects (nonasthmatic and nonwheezing) were chosen from Project Viva and Home Allergens, 2 population-based pediatric cohorts. Receiver operating characteristic curves were constructed, and areas under the curve were calculated for different BDR cutoffs. Results A total of 1041 cases (59.7% male; mean age, 8.9 ± 2.1 years) and 250 control subjects (46.8% male; mean age, 8.7 ± 1.7 years) were analyzed, with mean BDRs of 10.7% ± 10.2% and 2.7% ± 8.4%, respectively. The BDR test differentiated asthmatic patients from nonasthmatic patients with a moderate accuracy (area under the curve, 73.3%). Despite good specificity, a cutoff of 12% was associated with poor sensitivity (35.6%). A cutoff of less than 8% performed significantly better than a cutoff of 12% (P = .03, 8% vs 12%). Conclusions Our findings highlight the poor sensitivity associated with the commonly used 12% cutoff for BDR. Although our data show that a threshold of less than 8% performs better than 12%, given the variability of this test in children, we conclude that it might be not be appropriate to choose a specific BDR cutoff as a criterion for the diagnosis of asthma. PMID:23683464

  8. Speed accuracy trade-off under response deadlines

    PubMed Central

    Karşılar, Hakan; Simen, Patrick; Papadakis, Samantha; Balcı, Fuat

    2014-01-01

    Perceptual decision making has been successfully modeled as a process of evidence accumulation up to a threshold. In order to maximize the rewards earned for correct responses in tasks with response deadlines, participants should collapse decision thresholds dynamically during each trial so that a decision is reached before the deadline. This strategy ensures on-time responding, though at the cost of reduced accuracy, since slower decisions are based on lower thresholds and less net evidence later in a trial (compared to a constant threshold). Frazier and Yu (2008) showed that the normative rate of threshold reduction depends on deadline delays and on participants' uncertainty about these delays. Participants should start collapsing decision thresholds earlier when making decisions under shorter deadlines (for a given level of timing uncertainty) or when timing uncertainty is higher (for a given deadline). We tested these predictions using human participants in a random dot motion discrimination task. Each participant was tested in free-response, short deadline (800 ms), and long deadline conditions (1000 ms). Contrary to optimal-performance predictions, the resulting empirical function relating accuracy to response time (RT) in deadline conditions did not decline to chance level near the deadline; nor did the slight decline we typically observed relate to measures of endogenous timing uncertainty. Further, although this function did decline slightly with increasing RT, the decline was explainable by the best-fitting parameterization of Ratcliff's diffusion model (Ratcliff, 1978), whose parameters are constant within trials. Our findings suggest that at the very least, typical decision durations are too short for participants to adapt decision parameters within trials. PMID:25177265

  9. Evaluating the completeness and accuracy of MedWatch data.

    PubMed

    Getz, Kenneth A; Stergiopoulos, Stella; Kaitin, Kenneth I

    2014-01-01

    The Food and Drug Administration's MedWatch system--a voluntary surveillance program--received 600,000 adverse event reports on marketed drugs and devices in 2011. The Food and Drug Administration credits the MedWatch system with improving awareness, and expediting early detection, of drug and device risks and in illuminating the adoption of medical treatments. Reporting bias has been acknowledged as a limitation of the MedWatch system. No systematic assessment of the accuracy and completeness of adverse event reporting has been conducted, yet inaccurate adverse event reporting may lead drug safety professionals to draw incorrect conclusions, manufacturers may be wrongly forced to suspend and withdraw medications and interventions, health professionals may mistakenly alter their clinical practices, and patients may be denied safe and effective treatments. In 2011, the Tufts Center for the Study of Drug Development gathered and analyzed 10.2 million adverse event reports filed with the MedWatch system. Patient information was generally complete and accurate. Suspect product information, on the other hand, showed high levels of incomplete and inaccurate data. Start and end dates of suspect product use had 37% and 23% completion rates, respectively. Dosage level was completed only 31% of the time, and product lot numbers had only a 9% completion rate. More than 25% of the names of reported suspect products were inaccurate, and 31% of suspect product start dates were inaccurate. Higher levels of completion and accuracy were associated with reports filed closer to the date when the adverse event was observed. Implications of the results and suggested improvements are discussed.

  10. Time and position accuracy using codeless GPS

    NASA Technical Reports Server (NTRS)

    Dunn, C. E.; Jefferson, D. C.; Lichten, S. M.; Thomas, J. B.; Vigue, Y.; Young, L. E.

    1994-01-01

    The Global Positioning System has allowed scientists and engineers to make measurements having accuracy far beyond the original 15 meter goal of the system. Using global networks of P-Code capable receivers and extensive post-processing, geodesists have achieved baseline precision of a few parts per billion, and clock offsets have been measured at the nanosecond level over intercontinental distances. A cloud hangs over this picture, however. The Department of Defense plans to encrypt the P-Code (called Anti-Spoofing, or AS) in the fall of 1993. After this event, geodetic and time measurements will have to be made using codeless GPS receivers. However, there appears to be a silver lining to the cloud. In response to the anticipated encryption of the P-Code, the geodetic and GPS receiver community has developed some remarkably effective means of coping with AS without classified information. We will discuss various codeless techniques currently available and the data noise resulting from each. We will review some geodetic results obtained using only codeless data, and discuss the implications for time measurements. Finally, we will present the status of GPS research at JPL in relation to codeless clock measurements.

  11. Firing temperature accuracy of four dental furnaces.

    PubMed

    Haag, Per; Ciber, Edina; Dérand, Tore

    2011-01-01

    In spite of using recommended firing and displayed temperatures, low-fired dental porcelain more often demonstrates unsatisfactory results after firing than porcelain fired at higher temperatures. It could therefore be anticipated that temperatures shown on the display are incorrect, implying that the furnace does not render correct firing programs for low-fired porcelain. The purpose of this study is to investigate deviations from the real temperature during the firing process and also to illustrate the service and maintenance discipline of furnaces at dental laboratories. Totally 20 units of four different types of dental furnaces were selected for testing of temperature accuracy with usage of a digital temperature measurement apparatus, Therma 1. In addition,the staffs at 68 dental laboratories in Sweden were contacted for a telephone interview on furnace brand and on service and maintenance program performed at their laboratories. None of the 20 different dental furnaces in the study could generate the firing temperatures shown on the display, indicating that the hypothesis was correct. Multimat MCII had the least deviation of temperature compared with displayfigures. 62 out of 68 invited dental laboratories chose to participate in the interviews and the result was that very few laboratories had a service and maintenance program living up to quality standards. There is room for improving the precision of dental porcelain furnaces as there are deviations between displayed and read temperatures during the different steps of the firing process.

  12. Fragmentation functions beyond fixed order accuracy

    NASA Astrophysics Data System (ADS)

    Anderle, Daniele P.; Kaufmann, Tom; Stratmann, Marco; Ringer, Felix

    2017-03-01

    We give a detailed account of the phenomenology of all-order resummations of logarithmically enhanced contributions at small momentum fraction of the observed hadron in semi-inclusive electron-positron annihilation and the timelike scale evolution of parton-to-hadron fragmentation functions. The formalism to perform resummations in Mellin moment space is briefly reviewed, and all relevant expressions up to next-to-next-to-leading logarithmic order are derived, including their explicit dependence on the factorization and renormalization scales. We discuss the details pertinent to a proper numerical implementation of the resummed results comprising an iterative solution to the timelike evolution equations, the matching to known fixed-order expressions, and the choice of the contour in the Mellin inverse transformation. First extractions of parton-to-pion fragmentation functions from semi-inclusive annihilation data are performed at different logarithmic orders of the resummations in order to estimate their phenomenological relevance. To this end, we compare our results to corresponding fits up to fixed, next-to-next-to-leading order accuracy and study the residual dependence on the factorization scale in each case.

  13. Effect of data latency upon missile accuracy

    NASA Astrophysics Data System (ADS)

    Monroe, L. J.

    1983-12-01

    This study examined the effect of data latency upon air-to-air guided missile accuracy. This research was done by modeling a digital guided missile, inserting the model into a computer simulation and generating miss distance statistics. The digital guided missile was modeled after the DIS microcomputer architecture. The DIS (Digital Integrating Subsystem) approach involves a number of loosely coupled microprocessors which communicate over a serial multiplex bus. It was developed at the Air Force Armament Lab., Eglin AFB, FL. The missile simulation, Tactics IV, involves three degrees of freedom and is written in FORTRAN IV. It was developed by Science Applications, Inc. in conjunction with AFWAL/FIMB, Wright Patterson AFB, OH. The results of this study indicate that typical data latency values generate only small increases in miss distance. The maximum delays tested were .01 seconds and the average increase in miss distance was 2.12 feet. Additionally, it was discovered that the transmission rate of the DIS microcomputers greatly affected miss distance. Microcomputers transmitting at 10 HZ generated large miss distances, even without data latency present. The identical missile engagements using transmission rates of 100 HZ resulted in much smaller miss distances.

  14. Differential effects of differing intensities of acute exercise on speed and accuracy of cognition: a meta-analytical investigation.

    PubMed

    McMorris, Terry; Hale, Beverley J

    2012-12-01

    The primary purpose of this study was to examine, using meta-analytical techniques, the differential effects of differing intensities of acute exercise on speed and accuracy of cognition. Overall, exercise demonstrated a small, significant mean effect size (g=0.14, p<0.01) on cognition. Examination of the comparison between speed and accuracy dependent variables showed that speed accounted for most of the effect. For speed, moderate intensity exercise demonstrated a significantly larger mean effect size than those for low and high intensities. For speed of processing during moderate intensity exercise, central executive tasks showed a larger effect size than recall and alertness/attention tasks; and mean effect size for counterbalanced or randomized studies was significantly greater than for studies in which a pre-exercise followed by during or post-exercise protocol was used. There was no significant difference between mean effect sizes when testing took place post-exercise compared to during exercise for speed but accuracy studies demonstrated a significantly larger mean effect size post-exercise. It was concluded that increased arousal during moderate intensity exercise resulted in faster speed of processing. The very limited effect on accuracy may be due to the failure to choose tests which are complex enough to measure exercise-induced changes in accuracy of performance.

  15. Sun-pointing programs and their accuracy

    SciTech Connect

    Zimmerman, J.C.

    1981-05-01

    Several sun-pointing programs and their accuracy are described. FORTRAN program listings are given. Program descriptions are given for both Hewlett-Packard (HP-67) and Texas Instruments (TI-59) hand-held calculators.

  16. Critical thinking and accuracy of nurses' diagnoses.

    PubMed

    Lunney, Margaret

    2003-01-01

    Interpretations of patient data are complex and diverse, contributing to a risk of low accuracy nursing diagnoses. This risk is confirmed in research findings that accuracy of nurses' diagnoses varied widely from high to low. Highly accurate diagnoses are essential, however, to guide nursing interventions for the achievement of positive health outcomes. Development of critical thinking abilities is likely to improve accuracy of nurses' diagnoses. New views of critical thinking serve as a basis for critical thinking in nursing. Seven cognitive skills and ten habits of mind are identified as dimensions of critical thinking for use in the diagnostic process. Application of the cognitive skills of critical thinking illustrates the importance of using critical thinking for accuracy of nurses' diagnoses. Ten strategies are proposed for self-development of critical thinking abilities.

  17. Accuracy in fixing ship's positions by camera survey of bearings

    NASA Astrophysics Data System (ADS)

    Naus, Krzysztof; Wąż, Mariusz

    2011-01-01

    The paper presents the results of research on the possibilities of fixing ship position coordinates based on results of surveying bearings on navigational marks with the use of the CCD camera. Accuracy of the determination of ship position coordinates, expressed in terms of the mean error, was assumed to be the basic criterion of this estimation. The first part of the paper describes the method of the determination of the resolution and the mean error of the angle measurement, taken with a camera, and also the method of the determination of the mean error of position coordinates when two or more bearings were measured. There have been defined three software applications assigned for the development of navigational sea charts with accuracy areas mapped on. The second part contains the results of studying accuracy in fixing ship position coordinates, carried out in the Gulf of Gdansk, with the use of bearings taken obtained with the Rolleiflex and Sony cameras. The results are presented in a form of diagrams of the mean error of angle measurement, also in the form of navigational charts with accuracy fields mapped on. In the final part, basing on results obtained, the applicability of CCD cameras in automation of coastal navigation performance process is discussed.

  18. [Navigation in implantology: Accuracy assessment regarding the literature].

    PubMed

    Barrak, Ibrahim Ádám; Varga, Endre; Piffko, József

    2016-06-01

    Our objective was to assess the literature regarding the accuracy of the different static guided systems. After applying electronic literature search we found 661 articles. After reviewing 139 articles, the authors chose 52 articles for full-text evaluation. 24 studies involved accuracy measurements. Fourteen of our selected references were clinical and ten of them were in vitro (modell or cadaver). Variance-analysis (Tukey's post-hoc test; p < 0.05) was conducted to summarize the selected publications. Regarding 2819 results the average mean error at the entry point was 0.98 mm. At the level of the apex the average deviation was 1.29 mm while the mean of the angular deviation was 3,96 degrees. Significant difference could be observed between the two methods of implant placement (partially and fully guided sequence) in terms of deviation at the entry point, apex and angular deviation. Different levels of quality and quantity of evidence were available for assessing the accuracy of the different computer-assisted implant placement. The rapidly evolving field of digital dentistry and the new developments will further improve the accuracy of guided implant placement. In the interest of being able to draw dependable conclusions and for the further evaluation of the parameters used for accuracy measurements, randomized, controlled single or multi-centered clinical trials are necessary.

  19. Martial arts striking hand peak acceleration, accuracy and consistency.

    PubMed

    Neto, Osmar Pinto; Marzullo, Ana Carolina De Miranda; Bolander, Richard P; Bir, Cynthia A

    2013-01-01

    The goal of this paper was to investigate the possible trade-off between peak hand acceleration and accuracy and consistency of hand strikes performed by martial artists of different training experiences. Ten male martial artists with training experience ranging from one to nine years volunteered to participate in the experiment. Each participant performed 12 maximum effort goal-directed strikes. Hand acceleration during the strikes was obtained using a tri-axial accelerometer block. A pressure sensor matrix was used to determine the accuracy and consistency of the strikes. Accuracy was estimated by the radial distance between the centroid of each subject's 12 strikes and the target, whereas consistency was estimated by the square root of the 12 strikes mean squared distance from their centroid. We found that training experience was significantly correlated to hand peak acceleration prior to impact (r(2)=0.456, p =0.032) and accuracy (r(2)=0. 621, p=0.012). These correlations suggest that more experienced participants exhibited higher hand peak accelerations and at the same time were more accurate. Training experience, however, was not correlated to consistency (r(2)=0.085, p=0.413). Overall, our results suggest that martial arts training may lead practitioners to achieve higher striking hand accelerations with better accuracy and no change in striking consistency.

  20. Use of diabetes data management software reports by health care providers, patients with diabetes, and caregivers improves accuracy and efficiency of data analysis and interpretation compared with traditional logbook data: first results of the Accu-Chek Connect Reports Utility and Efficiency Study (ACCRUES).

    PubMed

    Hinnen, Deborah A; Buskirk, Ann; Lyden, Maureen; Amstutz, Linda; Hunter, Tracy; Parkin, Christopher G; Wagner, Robin

    2015-03-01

    We assessed users' proficiency and efficiency in identifying and interpreting self-monitored blood glucose (SMBG), insulin, and carbohydrate intake data using data management software reports compared with standard logbooks. This prospective, self-controlled, randomized study enrolled insulin-treated patients with diabetes (PWDs) (continuous subcutaneous insulin infusion [CSII] and multiple daily insulin injection [MDI] therapy), patient caregivers [CGVs]) and health care providers (HCPs) who were naïve to diabetes data management computer software. Six paired clinical cases (3 CSII, 3 MDI) and associated multiple-choice questions/answers were reviewed by diabetes specialists and presented to participants via a web portal in both software report (SR) and traditional logbook (TL) formats. Participant response time and accuracy were documented and assessed. Participants completed a preference questionnaire at study completion. All participants (54 PWDs, 24 CGVs, 33 HCPs) completed the cases. Participants achieved greater accuracy (assessed by percentage of accurate answers) using the SR versus TL formats: PWDs, 80.3 (13.2)% versus 63.7 (15.0)%, P < .0001; CGVs, 84.6 (8.9)% versus 63.6 (14.4)%, P < .0001; HCPs, 89.5 (8.0)% versus 66.4 (12.3)%, P < .0001. Participants spent less time (minutes) with each case using the SR versus TL formats: PWDs, 8.6 (4.3) versus 19.9 (12.2), P < .0001; CGVs, 7.0 (3.5) versus 15.5 (11.8), P = .0005; HCPs, 6.7 (2.9) versus 16.0 (12.0), P < .0001. The majority of participants preferred using the software reports versus logbook data. Use of the Accu-Chek Connect Online software reports enabled PWDs, CGVs, and HCPs, naïve to diabetes data management software, to identify and utilize key diabetes information with significantly greater accuracy and efficiency compared with traditional logbook information. Use of SRs was preferred over logbooks.

  1. The urine dipstick test useful to rule out infections. A meta-analysis of the accuracy

    PubMed Central

    Devillé, Walter LJM; Yzermans, Joris C; van Duijn, Nico P; Bezemer, P Dick; van der Windt, Daniëlle AWM; Bouter, Lex M

    2004-01-01

    Background Many studies have evaluated the accuracy of dipstick tests as rapid detectors of bacteriuria and urinary tract infections (UTI). The lack of an adequate explanation for the heterogeneity of the dipstick accuracy stimulates an ongoing debate. The objective of the present meta-analysis was to summarise the available evidence on the diagnostic accuracy of the urine dipstick test, taking into account various pre-defined potential sources of heterogeneity. Methods Literature from 1990 through 1999 was searched in Medline and Embase, and by reference tracking. Selected publications should be concerned with the diagnosis of bacteriuria or urinary tract infections, investigate the use of dipstick tests for nitrites and/or leukocyte esterase, and present empirical data. A checklist was used to assess methodological quality. Results 70 publications were included. Accuracy of nitrites was high in pregnant women (Diagnostic Odds Ratio = 165) and elderly people (DOR = 108). Positive predictive values were ≥80% in elderly and in family medicine. Accuracy of leukocyte-esterase was high in studies in urology patients (DOR = 276). Sensitivities were highest in family medicine (86%). Negative predictive values were high in both tests in all patient groups and settings, except for in family medicine. The combination of both test results showed an important increase in sensitivity. Accuracy was high in studies in urology patients (DOR = 52), in children (DOR = 46), and if clinical information was present (DOR = 28). Sensitivity was highest in studies carried out in family medicine (90%). Predictive values of combinations of positive test results were low in all other situations. Conclusions Overall, this review demonstrates that the urine dipstick test alone seems to be useful in all populations to exclude the presence of infection if the results of both nitrites and leukocyte-esterase are negative. Sensitivities of the combination of both tests vary between 68 and 88% in

  2. Neural Mechanisms of Speed-Accuracy Tradeoff

    PubMed Central

    Heitz, Richard P.; Schall, Jeffrey D.

    2012-01-01

    SUMMARY Intelligent agents balance speed of responding with accuracy of deciding. Stochastic accumulator models commonly explain this speed-accuracy tradeoff by strategic adjustment of response threshold. Several laboratories identify specific neurons in prefrontal and parietal cortex with this accumulation process, yet no neurophysiological correlates of speed-accuracy tradeoff have been described. We trained macaque monkeys to trade speed for accuracy on cue during visual search and recorded the activity of neurons in the frontal eye field. Unpredicted by any model, we discovered that speed-accuracy tradeoff is accomplished through several distinct adjustments. Visually responsive neurons modulated baseline firing rate, sensory gain, and the duration of perceptual processing. Movement neurons triggered responses with activity modulated in a direction opposite of model predictions. Thus, current stochastic accumulator models provide an incomplete description of the neural processes accomplishing speed-accuracy tradeoffs. The diversity of neural mechanisms was reconciled with the accumulator framework through an integrated accumulator model constrained by requirements of the motor system. PMID:23141072

  3. Research on target accuracy for ground-based lidar

    NASA Astrophysics Data System (ADS)

    Zhu, Ling; Shi, Ruoming

    2009-05-01

    In ground based Lidar system, the targets are used in the process of registration, georeferencing for point cloud, and also can be used as check points. Generally, the accuracy of capturing the flat target center is influenced by scanning range and scanning angle. In this research, the experiments are designed to extract accuracy index of the target center with 0-90°scan angles and 100-195 meter scan ranges using a Leica HDS3000 laser scanner. The data of the experiments are listed in detail and the related results are analyzed.

  4. Measurements of dimensional accuracy using linear and scanning profile techniques.

    PubMed

    Harrison, A; Huggett, R; Zissis, A

    1992-01-01

    Various measurement methods have been described for the determination of dimensional accuracy and stability of denture base materials. This investigation introduces a computerised coordinate measuring machine (CCMM) and compares it with two methods routinely used for assessment of the accuracy of fit of denture base materials. The results demonstrate that the three methods (digital calipers, optical comparator, and CCMM) are acceptable for linear measurement. The CCMM was also used in its scanning mode to define and to quantify the contour changes of the resin bases. The advantages of the CCMM become apparent when two-dimensional changes require assessment.

  5. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  6. Accuracy of impressions obtained with dual-arch trays.

    PubMed

    Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

    2009-01-01

    This study aimed to analyze the accuracy resulting from dual-arch impressions when compared to conventional impressions in complex preparations (ie, inlay and partial crown). One hundred eighty impressions were made using two different dual-arch trays; conventional trays served as the control. The accuracy of the dies obtained (Fuji-Rock EP, GC Europe) was assessed indirectly from the change of 59 transversal dimensions. Statistical analysis (t test, analysis of variance) revealed that less rigid dual-arch trays performed better than rigid ones. Though the inlay preparation was more difficult to reproduce with dual-arch trays, it can be concluded that the accuracy obtainable with nonrigid dual-arch trays is comparable to impressions taken from full-arch trays.

  7. High accuracy solutions of incompressible Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Gupta, Murli M.

    1990-01-01

    In recent years, high accuracy finite difference approximations were developed for partial differential equations of elliptic type, with particular emphasis on the convection-diffusion equation. These approximations are of compact type, have a local truncation error of fourth order, and allow the use of standard iterative schemes to solve the resulting systems of algebraic equations. These high accuracy approximations are extended to the solution of Navier-Stokes equations. Solutions are obtained for the model problem of driven cavity and are compared with solutions obtained using other approximations and those obtained by other authors. It is discovered that the high order approximations do indeed produce high accuracy solutions and have a potential for use in solving important problems of viscous fluid flows.

  8. Follow your breath: Respiratory interoceptive accuracy in experienced meditators

    PubMed Central

    DAUBENMIER, JENNIFER; SZE, JOCELYN; KERR, CATHERINE E.; KEMENY, MARGARET E.; MEHLING, WOLF

    2014-01-01

    Attention to internal bodily sensations is a core feature of mindfulness meditation. Previous studies have not detected differences in interoceptive accuracy between meditators and nonmeditators on heartbeat detection and perception tasks. We compared differences in respiratory interoceptive accuracy between meditators and nonmeditators in the ability to detect and discriminate respiratory resistive loads and sustain accurate perception of respiratory tidal volume during nondistracted and distracted conditions. Groups did not differ in overall performance on the detection and discrimination tasks; however, meditators were more accurate in discriminating the resistive load with the lowest ceiling effect. Meditators were also more accurate during the nondistracted tracking task at a lag time of 1 s following the breath. Results provide initial support for the notion that meditators have greater respiratory interoceptive accuracy compared to nonmeditators. PMID:23692525

  9. Signal processing of MEMS gyroscope arrays to improve accuracy using a 1st order Markov for rate signal modeling.

    PubMed

    Jiang, Chengyu; Xue, Liang; Chang, Honglong; Yuan, Guangmin; Yuan, Weizheng

    2012-01-01

    This paper presents a signal processing technique to improve angular rate accuracy of the gyroscope by combining the outputs of an array of MEMS gyroscope. A mathematical model for the accuracy improvement was described and a Kalman filter (KF) was designed to obtain optimal rate estimates. Especially, the rate signal was modeled by a first-order Markov process instead of a random walk to improve overall performance. The accuracy of the combined rate signal and affecting factors were analyzed using a steady-state covariance. A system comprising a six-gyroscope array was developed to test the presented KF. Experimental tests proved that the presented model was effective at improving the gyroscope accuracy. The experimental results indicated that six identical gyroscopes with an ARW noise of 6.2 °/√h and a bias drift of 54.14 °/h could be combined into a rate signal with an ARW noise of 1.8 °/√h and a bias drift of 16.3 °/h, while the estimated rate signal by the random walk model has an ARW noise of 2.4 °/√h and a bias drift of 20.6 °/h. It revealed that both models could improve the angular rate accuracy and have a similar performance in static condition. In dynamic condition, the test results showed that the first-order Markov process model could reduce the dynamic errors 20% more than the random walk model.

  10. High accuracy in situ radiometric mapping.

    PubMed

    Tyler, Andrew N

    2004-01-01

    In situ and airborne gamma ray spectrometry have been shown to provide rapid and spatially representative estimates of environmental radioactivity across a range of landscapes. However, one of the principal limitations of this technique has been the influence of changes in the vertical distribution of the source (e.g. 137Cs) on the observed photon fluence resulting in a significant reduction in the accuracy of the in situ activity measurement. A flexible approach for single gamma photon emitting radionuclides is presented, which relies on the quantification of forward scattering (or valley region between the full energy peak and Compton edge) within the gamma ray spectrum to compensate for changes in the 137Cs vertical activity distribution. This novel in situ method lends itself to the mapping of activity concentrations in environments that exhibit systematic changes in the vertical activity distribution. The robustness of this approach has been demonstrated in a salt marsh environment on the Solway coast, SW Scotland, with both a 7.6 cm x 7.6 cm NaI(Tl) detector and a 35% n-type HPGe detector. Application to ploughed field environments has also been demonstrated using HPGe detector, including its application to the estimation of field moist bulk density and soil erosion measurement. Ongoing research work is also outlined.

  11. Dimensional accuracy of thermoformed polymethyl methacrylate.

    PubMed

    Jagger, R G

    1996-12-01

    Thermoforming of polymethyl methacrylate sheet is used to produce a number of different types of dental appliances. The purpose of this study was to determine the dimensional accuracy of thermoformed polymethyl methacrylate specimens. Five blanks of the acrylic resin were thermoformed on stone casts prepared from a silicone mold of a brass master die. The distances between index marks were measured both on the cast and on the thermoformed blanks with an optical comparator. Measurements on the blanks were made again 24 hours after processing and then 1 week, 1 month, and 3 months after immersion in water. Linear shrinkage of less than 1% (range 0.37% to 0.52%) was observed 24 hours after removal of the blanks from the cast. Immersion of the thermoformed specimens in water resulted in an increase in measured dimensions, but after 3 months' immersion these increases were still less than those of the cast (range 0.07% to 0.18%). It was concluded that it is possible to thermoform Perspex polymethyl methacrylate accurately.

  12. Characterizing geometric accuracy and precision in image guided gated radiotherapy

    NASA Astrophysics Data System (ADS)

    Tenn, Stephen Edward

    Gated radiotherapy combined with intensity modulated or three-dimensional conformal radiotherapy for tumors in the thorax and abdomen can deliver dose distributions which conform closely to tumor shapes allowing increased tumor dose while sparing healthy tissues. These conformal fields require more accurate and precise placement than traditional fields or tumors may receive suboptimal dose thereby reducing tumor control probability. Image guidance based on four-dimensional computed tomography (4DCT) provides a means to improve accuracy and precision in radiotherapy. The ability of 4DCT to accurately reproduce patient geometry and the ability of image guided gating equipment to position tumors and place fields around them must be characterized in order to determine treatment parameters such as tumor margins. Fiducial based methods of characterizing accuracy and precision of equipment for 4DCT planning and image guided gated radiotherapy (IGGRT) are presented with results for specific equipment. Fiducial markers of known geometric orientation are used to characterize 4DCT image reconstruction accuracy. Accuracy is determined under different acquisition protocols, reconstruction phases, and phantom trajectories. Targeting accuracy of fiducial based image guided gating is assessed by measuring in-phantom field positions for different motions, gating levels and target rotations. Synchronization parameters for gating equipment are also determined. Finally, end-to-end testing is performed to assess overall accuracy and precision of the equipment under controlled conditions. 4DCT limits fiducial geometric distance errors to 2 mm for repeatable target trajectories and to 5 mm for a pseudo-random trajectory. Largest offsets were in the longitudinal direction. If correctly calibrated and synchronized, the IGGRT system tested here can target reproducibly moving tumors with accuracy better than 1.2 mm. Gating level can affect accuracy if target motion is asymmetric about the

  13. NUCLEAR DATA TARGET ACCURACY REQUIREMENTS FOR MA BURNERS

    SciTech Connect

    G. Palmiotti; M. Salvatores

    2011-06-01

    A nuclear data target accuracy assessment has been carried out for two types of transmuters: a critical sodium fast reactor(SFR) and an accelerator driven system (ADMAB). Results are provided for a 7 group energy structure. Considerations about fuel cycle parameters uncertainties illustrate their dependence from the isotope final densities at end of cycle.

  14. Impact factor for exclusive diffractive dijet production with NLO accuracy

    NASA Astrophysics Data System (ADS)

    Boussarie, R.; Grabovsky, A. V.; Szymanowski, L.; Wallon, S.

    2017-03-01

    Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results.

  15. Parameter Accuracy in Meta-Analyses of Factor Structures

    ERIC Educational Resources Information Center

    Gnambs, Timo; Staufenbiel, Thomas

    2016-01-01

    Two new methods for the meta-analysis of factor loadings are introduced and evaluated by Monte Carlo simulations. The direct method pools each factor loading individually, whereas the indirect method synthesizes correlation matrices reproduced from factor loadings. The results of the two simulations demonstrated that the accuracy of…

  16. Accuracy of Teacher Nominations of Child Behavior Problems.

    ERIC Educational Resources Information Center

    Green, Kenneth D.; And Others

    The purpose of this study was to examine the accuracy of teachers' abilities to identify problem children. Ninety-five third grade children served as subjects. Teachers designated each child as a conduct problem, withdrawal problem, or normal, resulting in 16, 14, and 65 children being assigned to the three groups. Behavioral observations, peer…

  17. 20 CFR 416.1043 - Performance accuracy standard.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Performance accuracy standard. 416.1043 Section 416.1043 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE... have been in the file but was not included, even though its inclusion does not change the result in...

  18. 20 CFR 404.1643 - Performance accuracy standard.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Performance accuracy standard. 404.1643 Section 404.1643 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND... have been in the file but was not included, even though its inclusion does not change the result in...

  19. Impulsivity and Speed-Accuracy Strategies in Intelligence Test Performance.

    ERIC Educational Resources Information Center

    Phillips, Louise H.; Rabbitt, Patrick M. A.

    1995-01-01

    Whether relations between intelligence test performance and information processing measures depend on individual differences in speed-accuracy preferences rather than capacity limitations and whether the impact of strategic variables changes with increasing age or extraversion was studied with 83 adults ages 50 to 79 years. Results are discussed…

  20. Estimating Classification Consistency and Accuracy for Cognitive Diagnostic Assessment

    ERIC Educational Resources Information Center

    Cui, Ying; Gierl, Mark J.; Chang, Hua-Hua

    2012-01-01

    This article introduces procedures for the computation and asymptotic statistical inference for classification consistency and accuracy indices specifically designed for cognitive diagnostic assessments. The new classification indices can be used as important indicators of the reliability and validity of classification results produced by…

  1. Increasing Accuracy in Computed Inviscid Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Dyson, Roger

    2004-01-01

    A technique has been devised to increase the accuracy of computational simulations of flows of inviscid fluids by increasing the accuracy with which surface boundary conditions are represented. This technique is expected to be especially beneficial for computational aeroacoustics, wherein it enables proper accounting, not only for acoustic waves, but also for vorticity and entropy waves, at surfaces. Heretofore, inviscid nonlinear surface boundary conditions have been limited to third-order accuracy in time for stationary surfaces and to first-order accuracy in time for moving surfaces. For steady-state calculations, it may be possible to achieve higher accuracy in space, but high accuracy in time is needed for efficient simulation of multiscale unsteady flow phenomena. The present technique is the first surface treatment that provides the needed high accuracy through proper accounting of higher-order time derivatives. The present technique is founded on a method known in art as the Hermitian modified solution approximation (MESA) scheme. This is because high time accuracy at a surface depends upon, among other things, correction of the spatial cross-derivatives of flow variables, and many of these cross-derivatives are included explicitly on the computational grid in the MESA scheme. (Alternatively, a related method other than the MESA scheme could be used, as long as the method involves consistent application of the effects of the cross-derivatives.) While the mathematical derivation of the present technique is too lengthy and complex to fit within the space available for this article, the technique itself can be characterized in relatively simple terms: The technique involves correction of surface-normal spatial pressure derivatives at a boundary surface to satisfy the governing equations and the boundary conditions and thereby achieve arbitrarily high orders of time accuracy in special cases. The boundary conditions can now include a potentially infinite number

  2. Knowing right from wrong in mental arithmetic judgments: calibration of confidence predicts the development of accuracy.

    PubMed

    Rinne, Luke F; Mazzocco, Michèle M M

    2014-01-01

    Does knowing when mental arithmetic judgments are right--and when they are wrong--lead to more accurate judgments over time? We hypothesize that the successful detection of errors (and avoidance of false alarms) may contribute to the development of mental arithmetic performance. Insight into error detection abilities can be gained by examining the "calibration" of mental arithmetic judgments-that is, the alignment between confidence in judgments and the accuracy of those judgments. Calibration may be viewed as a measure of metacognitive monitoring ability. We conducted a developmental longitudinal investigation of the relationship between the calibration of children's mental arithmetic judgments and their performance on a mental arithmetic task. Annually between Grades 5 and 8, children completed a problem verification task in which they rapidly judged the accuracy of arithmetic expressions (e.g., 25 + 50 = 75) and rated their confidence in each judgment. Results showed that calibration was strongly related to concurrent mental arithmetic performance, that calibration continued to develop even as mental arithmetic accuracy approached ceiling, that poor calibration distinguished children with mathematics learning disability from both low and typically achieving children, and that better calibration in Grade 5 predicted larger gains in mental arithmetic accuracy between Grades 5 and 8. We propose that good calibration supports the implementation of cognitive control, leading to long-term improvement in mental arithmetic accuracy. Because mental arithmetic "fluency" is critical for higher-level mathematics competence, calibration of confidence in mental arithmetic judgments may represent a novel and important developmental predictor of future mathematics performance.

  3. Evaluation of the Accuracy and Precision of a Next Generation Computer-Assisted Surgical System

    PubMed Central

    Dai, Yifei; Liebelt, Ralph A.; Gao, Bo; Gulbransen, Scott W.; Silver, Xeve S.

    2015-01-01

    Background Computer-assisted orthopaedic surgery (CAOS) improves accuracy and reduces outliers in total knee arthroplasty (TKA). However, during the evaluation of CAOS systems, the error generated by the guidance system (hardware and software) has been generally overlooked. Limited information is available on the accuracy and precision of specific CAOS systems with regard to intraoperative final resection measurements. The purpose of this study was to assess the accuracy and precision of a next generation CAOS system and investigate the impact of extra-articular deformity on the system-level errors generated during intraoperative resection measurement. Methods TKA surgeries were performed on twenty-eight artificial knee inserts with various types of extra-articular deformity (12 neutral, 12 varus, and 4 valgus). Surgical resection parameters (resection depths and alignment angles) were compared between postoperative three-dimensional (3D) scan-based measurements and intraoperative CAOS measurements. Using the 3D scan-based measurements as control, the accuracy (mean error) and precision (associated standard deviation) of the CAOS system were assessed. The impact of extra-articular deformity on the CAOS system measurement errors was also investigated. Results The pooled mean unsigned errors generated by the CAOS system were equal or less than 0.61 mm and 0.64° for resection depths and alignment angles, respectively. No clinically meaningful biases were found in the measurements of resection depths (< 0.5 mm) and alignment angles (< 0.5°). Extra-articular deformity did not show significant effect on the measurement errors generated by the CAOS system investigated. Conclusions This study presented a set of methodology and workflow to assess the system-level accuracy and precision of CAOS systems. The data demonstrated that the CAOS system investigated can offer accurate and precise intraoperative measurements of TKA resection parameters, regardless of the presence

  4. Accuracy and responses of genomic selection on key traits in apple breeding

    PubMed Central

    Muranty, Hélène; Troggio, Michela; Sadok, Inès Ben; Rifaï, Mehdi Al; Auwerkerken, Annemarie; Banchi, Elisa; Velasco, Riccardo; Stevanato, Piergiorgio; van de Weg, W Eric; Di Guardo, Mario; Kumar, Satish; Laurens, François; Bink, Marco C A M

    2015-01-01

    The application of genomic selection in fruit tree crops is expected to enhance breeding efficiency by increasing prediction accuracy, increasing selection intensity and decreasing generation interval. The objectives of this study were to assess the accuracy of prediction and selection response in commercial apple breeding programmes for key traits. The training population comprised 977 individuals derived from 20 pedigreed full-sib families. Historic phenotypic data were available on 10 traits related to productivity and fruit external appearance and genotypic data for 7829 SNPs obtained with an Illumina 20K SNP array. From these data, a genome-wide prediction model was built and subsequently used to calculate genomic breeding values of five application full-sib families. The application families had genotypes at 364 SNPs from a dedicated 512 SNP array, and these genotypic data were extended to the high-density level by imputation. These five families were phenotyped for 1 year and their phenotypes were compared to the predicted breeding values. Accuracy of genomic prediction across the 10 traits reached a maximum value of 0.5 and had a median value of 0.19. The accuracies were strongly affected by the phenotypic distribution and heritability of traits. In the largest family, significant selection response was observed for traits with high heritability and symmetric phenotypic distribution. Traits that showed non-significant response often had reduced and skewed phenotypic variation or low heritability. Among the five application families the accuracies were uncorrelated to the degree of relatedness to the training population. The results underline the potential of genomic prediction to accelerate breeding progress in outbred fruit tree crops that still need to overcome long generation intervals and extensive phenotyping costs. PMID:26744627

  5. Knowing Right From Wrong In Mental Arithmetic Judgments: Calibration Of Confidence Predicts The Development Of Accuracy

    PubMed Central

    Rinne, Luke F.; Mazzocco, Michèle M. M.

    2014-01-01

    Does knowing when mental arithmetic judgments are right—and when they are wrong—lead to more accurate judgments over time? We hypothesize that the successful detection of errors (and avoidance of false alarms) may contribute to the development of mental arithmetic performance. Insight into error detection abilities can be gained by examining the “calibration” of mental arithmetic judgments—that is, the alignment between confidence in judgments and the accuracy of those judgments. Calibration may be viewed as a measure of metacognitive monitoring ability. We conducted a developmental longitudinal investigation of the relationship between the calibration of children's mental arithmetic judgments and their performance on a mental arithmetic task. Annually between Grades 5 and 8, children completed a problem verification task in which they rapidly judged the accuracy of arithmetic expressions (e.g., 25+50 = 75) and rated their confidence in each judgment. Results showed that calibration was strongly related to concurrent mental arithmetic performance, that calibration continued to develop even as mental arithmetic accuracy approached ceiling, that poor calibration distinguished children with mathematics learning disability from both low and typically achieving children, and that better calibration in Grade 5 predicted larger gains in mental arithmetic accuracy between Grades 5 and 8. We propose that good calibration supports the implementation of cognitive control, leading to long-term improvement in mental arithmetic accuracy. Because mental arithmetic “fluency” is critical for higher-level mathematics competence, calibration of confidence in mental arithmetic judgments may represent a novel and important developmental predictor of future mathematics performance. PMID:24988539

  6. Accuracy of Lagrange-sinc functions as a basis set for electronic structure calculations of atoms and molecules

    SciTech Connect

    Choi, Sunghwan; Hong, Kwangwoo; Kim, Jaewook; Kim, Woo Youn

    2015-03-07

    We developed a self-consistent field program based on Kohn-Sham density functional theory using Lagrange-sinc functions as a basis set and examined its numerical accuracy for atoms and molecules through comparison with the results of Gaussian basis sets. The result of the Kohn-Sham inversion formula from the Lagrange-sinc basis set manifests that the pseudopotential method is essential for cost-effective calculations. The Lagrange-sinc basis set shows faster convergence of the kinetic and correlation energies of benzene as its size increases than the finite difference method does, though both share the same uniform grid. Using a scaling factor smaller than or equal to 0.226 bohr and pseudopotentials with nonlinear core correction, its accuracy for the atomization energies of the G2-1 set is comparable to all-electron complete basis set limits (mean absolute deviation ≤1 kcal/mol). The same basis set also shows small mean absolute deviations in the ionization energies, electron affinities, and static polarizabilities of atoms in the G2-1 set. In particular, the Lagrange-sinc basis set shows high accuracy with rapid convergence in describing density or orbital changes by an external electric field. Moreover, the Lagrange-sinc basis set can readily improve its accuracy toward a complete basis set limit by simply decreasing the scaling factor regardless of systems.

  7. Effect of atmospherics on beamforming accuracy

    NASA Technical Reports Server (NTRS)

    Alexander, Richard M.

    1990-01-01

    Two mathematical representations of noise due to atmospheric turbulence are presented. These representations are derived and used in computer simulations of the Bartlett Estimate implementation of beamforming. Beamforming is an array processing technique employing an array of acoustic sensors used to determine the bearing of an acoustic source. Atmospheric wind conditions introduce noise into the beamformer output. Consequently, the accuracy of the process is degraded and the bearing of the acoustic source is falsely indicated or impossible to determine. The two representations of noise presented here are intended to quantify the effects of mean wind passing over the array of sensors and to correct for these effects. The first noise model is an idealized case. The effect of the mean wind is incorporated as a change in the propagation velocity of the acoustic wave. This yields an effective phase shift applied to each term of the spatial correlation matrix in the Bartlett Estimate. The resultant error caused by this model can be corrected in closed form in the beamforming algorithm. The second noise model acts to change the true direction of propagation at the beginning of the beamforming process. A closed form correction for this model is not available. Efforts to derive effective means to reduce the contributions of the noise have not been successful. In either case, the maximum error introduced by the wind is a beam shift of approximately three degrees. That is, the bearing of the acoustic source is indicated at a point a few degrees from the true bearing location. These effects are not quite as pronounced as those seen in experimental results. Sidelobes are false indications of acoustic sources in the beamformer output away from the true bearing angle. The sidelobes that are observed in experimental results are not caused by these noise models. The effects of mean wind passing over the sensor array as modeled here do not alter the beamformer output as

  8. Accuracy assessment of the global ionospheric model over the Southern Ocean based on dynamic observation

    NASA Astrophysics Data System (ADS)

    Luo, Xiaowen; Xu, Huajun; Li, Zishen; Zhang, Tao; Gao, Jinyao; Shen, Zhongyan; Yang, Chunguo; Wu, Ziyin

    2017-02-01

    The global ionospheric model based on the reference stations of the Global Navigation Satellite System (GNSS) of the International GNSS Services is presently the most commonly used products of the global ionosphere. It is very important to comprehensively analyze and evaluate the accuracy and reliability of the model for the reasonable use of this kind of ionospheric product. In terms of receiver station deployment, this work is different from the traditional performance evaluation of the global ionosphere model based on observation data of ground-based static reference stations. The preliminary evaluation and analysis of the the global ionospheric model was conducted with the dynamic observation data across different latitudes over the southern oceans. The validation results showed that the accuracy of the global ionospheric model over the southern oceans is about 5 TECu, which deviates from the measured ionospheric TEC by about -0.6 TECu.

  9. One high-accuracy camera calibration algorithm based on computer vision images

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Huang, Jianming; Wei, Xiangquan

    2015-12-01

    Camera calibration is the first step of computer vision and one of the most active research fields nowadays. In order to improve the measurement precision, the internal parameters of the camera should be accurately calibrated. So one high-accuracy camera calibration algorithm is proposed based on the images of planar targets or tridimensional targets. By using the algorithm, the internal parameters of the camera are calibrated based on the existing planar target at the vision-based navigation experiment. The experimental results show that the accuracy of the proposed algorithm is obviously improved compared with the conventional linear algorithm, Tsai general algorithm, and Zhang Zhengyou calibration algorithm. The algorithm proposed by the article can satisfy the need of computer vision and provide reference for precise measurement of the relative position and attitude.

  10. Volume of the human septal forebrain region is a predictor of source memory accuracy.

    PubMed

    Butler, Tracy; Blackmon, Karen; Zaborszky, Laszlo; Wang, Xiuyuan; DuBois, Jonathan; Carlson, Chad; Barr, William B; French, Jacqueline; Devinsky, Orrin; Kuzniecky, Ruben; Halgren, Eric; Thesen, Thomas

    2012-01-01

    Septal nuclei, components of basal forebrain, are strongly and reciprocally connected with hippocampus, and have been shown in animals to play a critical role in memory. In humans, the septal forebrain has received little attention. To examine the role of human septal forebrain in memory, we acquired high-resolution magnetic resonance imaging scans from 25 healthy subjects and calculated septal forebrain volume using recently developed probabilistic cytoarchitectonic maps. We indexed memory with the California Verbal Learning Test-II. Linear regression showed that bilateral septal forebrain volume was a significant positive predictor of recognition memory accuracy. More specifically, larger septal forebrain volume was associated with the ability to recall item source/context accuracy. Results indicate specific involvement of septal forebrain in human source memory, and recall the need for additional research into the role of septal nuclei in memory and other impairments associated with human diseases.

  11. High accuracy digital aging monitor based on PLL-VCO circuit

    NASA Astrophysics Data System (ADS)

    Yuejun, Zhang; Zhidi, Jiang; Pengjun, Wang; Xuelong, Zhang

    2015-01-01

    As the manufacturing process is scaled down to the nanoscale, the aging phenomenon significantly affects the reliability and lifetime of integrated circuits. Consequently, the precise measurement of digital CMOS aging is a key aspect of nanoscale aging tolerant circuit design. This paper proposes a high accuracy digital aging monitor using phase-locked loop and voltage-controlled oscillator (PLL-VCO) circuit. The proposed monitor eliminates the circuit self-aging effect for the characteristic of PLL, whose frequency has no relationship with circuit aging phenomenon. The PLL-VCO monitor is implemented in TSMC low power 65 nm CMOS technology, and its area occupies 303.28 × 298.94 μm2. After accelerating aging tests, the experimental results show that PLL-VCO monitor improves accuracy about high temperature by 2.4% and high voltage by 18.7%.

  12. Relationship between motor variability, accuracy, and ball speed in the tennis serve.

    PubMed

    Antúnez, Ruperto Menayo; Hernández, Francisco Javier Moreno; García, Juan Pedro Fuentes; Vaíllo, Raúl Reina; Arroyo, Jesús Sebastián Damas

    2012-06-01

    The main objective of this study was to analyze the motor variability in the performance of the tennis serve and its relationship to performance outcome. Seventeen male tennis players took part in the research, and they performed 20 serves. Linear and non-linear variability during the hand movement was measured by 3D Motion Tracking. Ball speed was recorded with a sports radar gun and the ball bounces were video recorded to calculate accuracy. The results showed a relationship between the amount of variability and its non-linear structure found in performance of movement and the outcome of the serve. The study also found that movement predictability correlates with performance. An increase in the amount of movement variability could affect the tennis serve performance in a negative way by reducing speed and accuracy of the ball.

  13. Ab Initio Calculation of Rate Constants for Molecule–Surface Reactions with Chemical Accuracy

    PubMed Central

    Piccini, GiovanniMaria; Alessio, Maristella

    2016-01-01

    Abstract The ab initio prediction of reaction rate constants for systems with hundreds of atoms with an accuracy that is comparable to experiment is a challenge for computational quantum chemistry. We present a divide‐and‐conquer strategy that departs from the potential energy surfaces obtained by standard density functional theory with inclusion of dispersion. The energies of the reactant and transition structures are refined by wavefunction‐type calculations for the reaction site. Thermal effects and entropies are calculated from vibrational partition functions, and the anharmonic frequencies are calculated separately for each vibrational mode. This method is applied to a key reaction of an industrially relevant catalytic process, the methylation of small alkenes over zeolites. The calculated reaction rate constants (free energies), pre‐exponential factors (entropies), and enthalpy barriers show that our computational strategy yields results that agree with experiment within chemical accuracy limits (less than one order of magnitude). PMID:27008460

  14. [Discussion about the prediction accuracy for dynamic spectrum by partial FFT].

    PubMed

    Li, Gang; Li, Qiu-xia; Lin, Ling; Li, Xiao-xia; Wang, Yan; Liu, Yu-liang

    2006-12-01

    The development of near-infrared-based techniques for the noninvasive determination of blood component concentrations has attracted significant interest in recent years. But the noninvasive measurement of blood compositions has not yet been applied to the clinical field except blood oxygen saturation. The most important and also difficult problems are the effects of individual discrepancy and complicated measurement conditions. In the present article, the approach of dynamic spectrum (DS) is introduced, which is based on the principle of photoplethysmography. It is very difficult too to pick up DS with high precision in time domain. In order to extract the DS with high accuracy, the FFT method and it's leakage are discussed. The influences of sampling speed, sampling signal periodicity, window function and unsynchronized sample are analyzed by emulating experiments. The result of emulating experiments shows that choosing certain sampling speed, sampling signal periodicity, window function and interpolation arithmetic will improve accuracy observably. This provides necessary condition for the clinical application of DS.

  15. Fast and High Accuracy Multigrid Solution of the Three Dimensional Poisson Equation

    NASA Astrophysics Data System (ADS)

    Zhang, Jun

    1998-07-01

    We employ a fourth-order compact finite difference scheme (FOS) with the multigrid algorithm to solve the three dimensional Poisson equation. We test the influence of different orderings of the grid space and different grid-transfer operators on the convergence and efficiency of our high accuracy algorithm. Fourier smoothing analysis is conducted to show that FOS has a smaller smoothing factor than the traditional second-order central difference scheme (CDS). A new method of Fourier smoothing analysis is proposed for the partially decoupled red-black Gauss-Seidel relaxation with FOS. Numerical results are given to compare the computed accuracy and the computational efficiency of FOS with multigrid against CDS with multigrid.

  16. Measurement accuracy of articulated arm CMMs with circular grating eccentricity errors

    NASA Astrophysics Data System (ADS)

    Zheng, Dateng; Yin, Sanfeng; Luo, Zhiyang; Zhang, Jing; Zhou, Taiping

    2016-11-01

    The 6 circular grating eccentricity errors model attempts to improve the measurement accuracy of an articulated arm coordinate measuring machine (AACMM) without increasing the corresponding hardware cost. We analyzed the AACMM’s circular grating eccentricity and obtained the 6 joints’ circular grating eccentricity error model parameters by conducting circular grating eccentricity error experiments. We completed the calibration operations for the measurement models by using home-made standard bar components. Our results show that the measurement errors from the AACMM’s measurement model without and with circular grating eccentricity errors are 0.0834 mm and 0.0462 mm, respectively. Significantly, we determined that measurement accuracy increased by about 44.6% when the circular grating eccentricity errors were corrected. This study is significant because it promotes wider applications of AACMMs both in theory and in practice.

  17. Relationship Between Motor Variability, Accuracy, and Ball Speed in the Tennis Serve

    PubMed Central

    Antúnez, Ruperto Menayo; Hernández, Francisco Javier Moreno; García, Juan Pedro Fuentes; Vaíllo, Raúl Reina; Arroyo, Jesús Sebastián Damas

    2012-01-01

    The main objective of this study was to analyze the motor variability in the performance of the tennis serve and its relationship to performance outcome. Seventeen male tennis players took part in the research, and they performed 20 serves. Linear and non-linear variability during the hand movement was measured by 3D Motion Tracking. Ball speed was recorded with a sports radar gun and the ball bounces were video recorded to calculate accuracy. The results showed a relationship between the amount of variability and its non-linear structure found in performance of movement and the outcome of the serve. The study also found that movement predictability correlates with performance. An increase in the amount of movement variability could affect the tennis serve performance in a negative way by reducing speed and accuracy of the ball. PMID:23486998

  18. High-accuracy deep-UV Ramsey-comb spectroscopy in krypton

    NASA Astrophysics Data System (ADS)

    Galtier, Sandrine; Altmann, Robert K.; Dreissen, Laura S.; Eikema, Kjeld S. E.

    2017-01-01

    In this paper, we present a detailed account of the first precision Ramsey-comb spectroscopy in the deep UV. We excite krypton in an atomic beam using pairs of frequency-comb laser pulses that have been amplified to the millijoule level and upconverted through frequency doubling in BBO crystals. The resulting phase-coherent deep-UV pulses at 212.55 nm are used in the Ramsey-comb method to excite the two-photon 4p^6 → 4p^5 5p [1/2 ]_0 transition. For the {}^{84}Kr isotope, we find a transition frequency of 2829833101679(103) kHz. The fractional accuracy of 3.7 × 10^{-11} is 34 times better than previous measurements, and also the isotope shifts are measured with improved accuracy. This demonstration shows the potential of Ramsey-comb excitation for precision spectroscopy at short wavelengths.

  19. The analysis of measurement accuracy of the parallel binocular stereo vision system

    NASA Astrophysics Data System (ADS)

    Yu, Huan; Xing, Tingwen; Jia, Xin

    2016-09-01

    Parallel binocular stereo vision system is a special form of binocular vision system. In order to simulate the human eyes observation state, the two cameras used to obtain images of the target scene are placed parallel to each other. This paper built a triangular geometric model, analyzed the structure parameters of parallel binocular stereo vision system and the correlations between them, and discussed the influences of baseline distance B between two cameras, the focal length f, the angle of view ω and other structural parameters on the accuracy of measurement. This paper used Matlab software to test the error function of parallel binocular stereo vision system under different structure parameters, and the simulation results showed the range of structure parameters when errors were small, thereby improved the accuracy of parallel binocular stereo vision system.

  20. Assessing the accuracy of image tracking algorithms on visible and thermal imagery using a deep restricted Boltzmann machine

    NASA Astrophysics Data System (ADS)

    Won, Stephen; Young, S. Susan

    2012-06-01

    Image tracking algorithms are critical to many applications including image super-resolution and surveillance. However, there exists no method to independently verify the accuracy of the tracking algorithm without a supplied control or visual inspection. This paper proposes an image tracking framework that uses deep restricted Boltzmann machines trained without external databases to quantify the accuracy of image tracking algorithms without the use of ground truths. In this paper, the tracking algorithm is comprised of the combination of flux tensor segmentation with four image registration methods, including correlation, Horn-Schunck optical flow, Lucas-Kanade optical flow, and feature correspondence methods. The robustness of the deep restricted Boltzmann machine is assessed by comparing between results from training with trusted and not-trusted data. Evaluations show that the deep restricted Boltzmann machine is a valid mechanism to assess the accuracy of a tracking algorithm without the use of ground truths.

  1. Improving accuracy through density correction in guided wave tomography

    PubMed Central

    2016-01-01

    The accurate quantification of wall loss caused by corrosion is critical to the reliable life estimation of pipes and pressure vessels. Traditional thickness gauging by scanning a probe is slow and requires access to all points on the surface; this is impractical in many cases as corrosion often occurs where access is restricted, such as beneath supports where water collects. Guided wave tomography presents a solution to this; by transmitting guided waves through the region of interest and exploiting their dispersive nature, it is possible to build up a map of thickness. While the best results have been seen when using the fundamental modes A0 and S0 at low frequency, the complex scattering of the waves causes errors within the reconstruction. It is demonstrated that these lead to an underestimate in wall loss for A0 but an overestimate for S0. Further analysis showed that this error was related to density variation, which was proportional to thickness. It was demonstrated how this could be corrected for in the reconstructions, in many cases resulting in the near-elimination of the error across a range of defects, and greatly improving the accuracy of life estimates from guided wave tomography. PMID:27118904

  2. Accuracy and Reliability of the Kinect Version 2 for Clinical Measurement of Motor Function

    PubMed Central

    Kayser, Bastian; Mansow-Model, Sebastian; Verrel, Julius; Paul, Friedemann; Brandt, Alexander U.; Schmitz-Hübsch, Tanja

    2016-01-01

    Background The introduction of low cost optical 3D motion tracking sensors provides new options for effective quantification of motor dysfunction. Objective The present study aimed to evaluate the Kinect V2 sensor against a gold standard motion capture system with respect to accuracy of tracked landmark movements and accuracy and repeatability of derived clinical parameters. Methods Nineteen healthy subjects were concurrently recorded with a Kinect V2 sensor and an optical motion tracking system (Vicon). Six different movement tasks were recorded with 3D full-body kinematics from both systems. Tasks included walking in different conditions, balance and adaptive postural control. After temporal and spatial alignment, agreement of movements signals was described by Pearson’s correlation coefficient and signal to noise ratios per dimension. From these movement signals, 45 clinical parameters were calculated, including ranges of motions, torso sway, movement velocities and cadence. Accuracy of parameters was described as absolute agreement, consistency agreement and limits of agreement. Intra-session reliability of 3 to 5 measurement repetitions was described as repeatability coefficient and standard error of measurement for each system. Results Accuracy of Kinect V2 landmark movements was moderate to excellent and depended on movement dimension, landmark location and performed task. Signal to noise ratio provided information about Kinect V2 landmark stability and indicated larger noise behaviour in feet and ankles. Most of the derived clinical parameters showed good to excellent absolute agreement (30 parameters showed ICC(3,1) > 0.7) and consistency (38 parameters showed r > 0.7) between both systems. Conclusion Given that this system is low-cost, portable and does not require any sensors to be attached to the body, it could provide numerous advantages when compared to established marker- or wearable sensor based system. The Kinect V2 has the potential to be used

  3. Diffraction based overlay metrology: accuracy and performance on front end stack

    NASA Astrophysics Data System (ADS)

    Leray, Philippe; Cheng, Shaunee; Kandel, Daniel; Adel, Michael; Marchelli, Anat; Vakshtein, Irina; Vasconi, Mauro; Salski, Bartlomiej

    2008-03-01

    The overlay metrology budget is typically 1/10 of the overlay control budget resulting in overlay metrology total measurement uncertainty requirements of 0.57 nm for the most challenging use cases of the 32nm technology generation. Theoretical considerations show that overlay technology based on differential signal scatterometry (SCOL TM) has inherent advantages, which will allow it to achieve the 32nm technology generation requirements and go beyond it. In this work we present results of an experimental and theoretical study of SCOL. We present experimental results, comparing this technology with the standard imaging overlay metrology. In particular, we present performance results, such as precision and tool induced shift, for different target designs. The response to a large range of induced misalignment is also shown. SCOL performance on these targets for a real stack is reported. We also show results of simulations of the expected accuracy and performance associated with a variety of scatterometry overlay target designs. The simulations were carried out on several stacks including FEOL and BEOL materials. The inherent limitations and possible improvements of the SCOL technology are discussed. We show that with the appropriate target design and algorithms, scatterometry overlay achieves the accuracy required for future technology generations.

  4. Enhancing Predictive Accuracy of Cardiac Autonomic Neuropathy Using Blood Biochemistry Features and Iterative Multitier Ensembles.

    PubMed

    Abawajy, Jemal; Kelarev, Andrei; Chowdhury, Morshed U; Jelinek, Herbert F

    2016-01-01

    Blood biochemistry attributes form an important class of tests, routinely collected several times per year for many patients with diabetes. The objective of this study is to investigate the role of blood biochemistry for improving the predictive accuracy of the diagnosis of cardiac autonomic neuropathy (CAN) progression. Blood biochemistry contributes to CAN, and so it is a causative factor that can provide additional power for the diagnosis of CAN especially in the absence of a complete set of Ewing tests. We introduce automated iterative multitier ensembles (AIME) and investigate their performance in comparison to base classifiers and standard ensemble classifiers for blood biochemistry attributes. AIME incorporate diverse ensembles into several tiers simultaneously and combine them into one automatically generated integrated system so that one ensemble acts as an integral part of another ensemble. We carried out extensive experimental analysis using large datasets from the diabetes screening research initiative (DiScRi) project. The results of our experiments show that several blood biochemistry attributes can be used to supplement the Ewing battery for the detection of CAN in situations where one or more of the Ewing tests cannot be completed because of the individual difficulties faced by each patient in performing the tests. The results show that AIME provide higher accuracy as a multitier CAN classification paradigm. The best predictive accuracy of 99.57% has been obtained by the AIME combining decorate on top tier with bagging on middle tier based on random forest. Practitioners can use these findings to increase the accuracy of CAN diagnosis.

  5. Dispersal and extrapolation on the accuracy of temporal predictions from distribution models for the Darwin's frog.

    PubMed

    Uribe-Rivera, David E; Soto-Azat, Claudio; Valenzuela-Sánchez, Andrés; Bizama, Gustavo; Simonetti, Javier A; Pliscoff, Patricio

    2017-04-11

    Climate change is a major threat to biodiversity; the development of models that reliably predict its effects on species distributions is a priority for conservation biogeography. Two of the main issues for accurate temporal predictions from Species Distribution Models (SDM) are model extrapolation and unrealistic dispersal scenarios. We assessed the consequences of these issues on the accuracy of climate-driven SDM predictions for the dispersal-limited Darwin's frog Rhinoderma darwinii in South America. We calibrated models using historical data (1950-1975) and projected them across 40 years to predict distribution under current climatic conditions, assessing predictive accuracy through the area under the ROC curve (AUC) and True Skill Statistics (TSS), contrasting binary model predictions against temporal-independent validation dataset (i.e. current presences/absences). To assess the effects of incorporating dispersal processes we compared the predictive accuracy of dispersal constrained models with no dispersal limited SDMs; and to assess the effects of model extrapolation on the predictive accuracy of SDMs, we compared this between extrapolated and no extrapolated areas. The incorporation of dispersal processes enhanced predictive accuracy, mainly due to a decrease in the false presence rate of model predictions, which is consistent with discrimination of suitable but inaccessible habitat. This also had consequences on range size changes over time, which is the most used proxy for extinction risk from climate change. The area of current climatic conditions that was absent in the baseline conditions (i.e. extrapolated areas) represents 39% of the study area, leading to a significant decrease in predictive accuracy of model predictions for those areas. Our results highlight 1) Incorporating dispersal processes can improve predictive accuracy of temporal transference of SDMs, and reduce uncertainties of extinction risk assessments from global change; 2) As

  6. Effects of hand termination and accuracy constraint on eye-hand coordination during sequential two-segment movements.

    PubMed

    Rand, Miya K; Stelmach, George E

    2010-12-01

    The purpose of this study was to examine the effects of accuracy constraints and termination requirements of hand movement on eye-hand coordination. Healthy adults performed two-segment eye and hand aiming movements to predetermined stationary targets. While two-segment eye movements were made to the first and second targets for all conditions, hand movements were varied across conditions. The first segment had two target sizes to alter accuracy constraints. There were three hand movement types with different termination requirements: (1) stop both at the first and at the second targets, (2) stop at the first target and discontinue, and (3) move through the first target and discontinue. The results showed that the initiation of saccades was moderately correlated with the initiation of hand movements, and both initiations changed in a similar fashion depending on various hand termination requirements. Amplitude of primary saccades and frequency of corrective saccades during the first segment were affected by the combined effects of accuracy constraints and hand termination requirements. These results suggest that the planning and execution of saccades are based in part on global task constraints related to the accuracy and termination demands of hand movements over the two segments. During the transition from the first to the second segment, the gaze was held on the first target until shortly after the pointing to that target was terminated, showing gaze anchoring. The gaze anchoring was prolonged due to the increased accuracy constraint of that target or by including pointing to the second target. However, the gaze anchoring was broken prior to the completion of pointing when the accuracy constraint was reduced and pointing to the second target was excluded. The observed modifications of gaze anchoring imply that the oculomotor system is functionally obligated to fixate a gaze to a pointing target only to the extent that successful completion of a pointing task is

  7. Activity monitor accuracy in persons using canes.

    PubMed

    Wendland, Deborah Michael; Sprigle, Stephen H

    2012-01-01

    The StepWatch activity monitor has not been validated on multiple indoor and outdoor surfaces in a population using ambulation aids. The aims of this technical report are to report on strategies to configure the StepWatch activity monitor on subjects using a cane and to report the accuracy of both leg-mounted and cane-mounted StepWatch devices on people ambulating over different surfaces while using a cane. Sixteen subjects aged 67 to 85 yr (mean 75.6) who regularly use a cane for ambulation participated. StepWatch calibration was performed by adjusting sensitivity and cadence. Following calibration optimization, accuracy was tested on both the leg-mounted and cane-mounted devices on different surfaces, including linoleum, sidewalk, grass, ramp, and stairs. The leg-mounted device had an accuracy of 93.4% across all surfaces, while the cane-mounted device had an aggregate accuracy of 84.7% across all surfaces. Accuracy of the StepWatch on the stairs was significantly less accurate (p < 0.001) when comparing surfaces using repeated measures analysis of variance. When monitoring community mobility, placement of a StepWatch on a person and his/her ambulation aid can accurately document both activity and device use.

  8. Accuracy metrics for judging time scale algorithms

    NASA Technical Reports Server (NTRS)

    Douglas, R. J.; Boulanger, J.-S.; Jacques, C.

    1994-01-01

    Time scales have been constructed in different ways to meet the many demands placed upon them for time accuracy, frequency accuracy, long-term stability, and robustness. Usually, no single time scale is optimum for all purposes. In the context of the impending availability of high-accuracy intermittently-operated cesium fountains, we reconsider the question of evaluating the accuracy of time scales which use an algorithm to span interruptions of the primary standard. We consider a broad class of calibration algorithms that can be evaluated and compared quantitatively for their accuracy in the presence of frequency drift and a full noise model (a mixture of white PM, flicker PM, white FM, flicker FM, and random walk FM noise). We present the analytic techniques for computing the standard uncertainty for the full noise model and this class of calibration algorithms. The simplest algorithm is evaluated to find the average-frequency uncertainty arising from the noise of the cesium fountain's local oscillator and from the noise of a hydrogen maser transfer-standard. This algorithm and known noise sources are shown to permit interlaboratory frequency transfer with a standard uncertainty of less than 10(exp -15) for periods of 30-100 days.

  9. Photogrammetric Accuracy and Modeling of Rolling Shutter Cameras

    NASA Astrophysics Data System (ADS)

    Vautherin, Jonas; Rutishauser, Simon; Schneider-Zapp, Klaus; Choi, Hon Fai; Chovancova, Venera; Glass, Alexis; Strecha, Christoph

    2016-06-01

    Unmanned aerial vehicles (UAVs) are becoming increasingly popular in professional mapping for stockpile analysis, construction site monitoring, and many other applications. Due to their robustness and competitive pricing, consumer UAVs are used more and more for these applications, but they are usually equipped with rolling shutter cameras. This is a significant obstacle when it comes to extracting high accuracy measurements using available photogrammetry software packages. In this paper, we evaluate the impact of the rolling shutter cameras of typical consumer UAVs on the accuracy of a 3D reconstruction. Hereto, we use a beta-version of the Pix4Dmapper 2.1 software to compare traditional (non rolling shutter) camera models against a newly implemented rolling shutter model with respect to both the accuracy of geo-referenced validation points and to the quality of the motion estimation. Multiple datasets have been acquired using popular quadrocopters (DJI Phantom 2 Vision+, DJI Inspire 1 and 3DR Solo) following a grid flight plan. For comparison, we acquired a dataset using a professional mapping drone (senseFly eBee) equipped with a global shutter camera. The bundle block adjustment of each dataset shows a significant accuracy improvement on validation ground control points when applying the new rolling shutter camera model for flights at higher speed (8m=s). Competitive accuracies can be obtained by using the rolling shutter model, although global shutter cameras are still superior. Furthermore, we are able to show that the speed of the drone (and its direction) can be solely estimated from the rolling shutter effect of the camera.

  10. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    SciTech Connect

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-03-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties.

  11. Evaluation of radiographers’ mammography screen-reading accuracy in Australia

    SciTech Connect

    Debono, Josephine C; Poulos, Ann E; Houssami, Nehmat; Turner, Robin M; Boyages, John

    2015-03-15

    This study aimed to evaluate the accuracy of radiographers’ screen-reading mammograms. Currently, radiologist workforce shortages may be compromising the BreastScreen Australia screening program goal to detect early breast cancer. The solution to a similar problem in the United Kingdom has successfully encouraged radiographers to take on the role as one of two screen-readers. Prior to consideration of this strategy in Australia, educational and experiential differences between radiographers in the United Kingdom and Australia emphasise the need for an investigation of Australian radiographers’ screen-reading accuracy. Ten radiographers employed by the Westmead Breast Cancer Institute with a range of radiographic (median = 28 years), mammographic (median = 13 years) and BreastScreen (median = 8 years) experience were recruited to blindly and independently screen-read an image test set of 500 mammograms, without formal training. The radiographers indicated the presence of an abnormality using BI-RADS®. Accuracy was determined by comparison with the gold standard of known outcomes of pathology results, interval matching and client 6-year follow-up. Individual sensitivity and specificity levels ranged between 76.0% and 92.0%, and 74.8% and 96.2% respectively. Pooled screen-reader accuracy across the radiographers estimated sensitivity as 82.2% and specificity as 89.5%. Areas under the reading operating characteristic curve ranged between 0.842 and 0.923. This sample of radiographers in an Australian setting have adequate accuracy levels when screen-reading mammograms. It is expected that with formal screen-reading training, accuracy levels will improve, and with support, radiographers have the potential to be one of the two screen-readers in the BreastScreen Australia program, contributing to timeliness and improved program outcomes.

  12. Effect of calibration method on Tekscan sensor accuracy.

    PubMed

    Brimacombe, Jill M; Wilson, David R; Hodgson, Antony J; Ho, Karen C T; Anglin, Carolyn

    2009-03-01

    Tekscan pressure sensors are used in biomechanics research to measure joint contact loads. While the overall accuracy of these sensors has been reported previously, the effects of different calibration algorithms on sensor accuracy have not been compared. The objectives of this validation study were to determine the most appropriate calibration method supplied in the Tekscan program software and to compare its accuracy to the accuracy obtained with two user-defined calibration protocols. We evaluated the calibration accuracies for test loads within the low range, high range, and full range of the sensor. Our experimental setup used materials representing those found in standard prosthetic joints, i.e., metal against plastic. The Tekscan power calibration was the most accurate of the algorithms provided with the system software, with an overall rms error of 2.7% of the tested sensor range, whereas the linear calibrations resulted in an overall rms error of up to 24% of the tested range. The user-defined ten-point cubic calibration was almost five times more accurate, on average, than the power calibration over the full range, with an overall rms error of 0.6% of the tested range. The user-defined three-point quadratic calibration was almost twice as accurate as the Tekscan power calibration, but was sensitive to the calibration loads used. We recommend that investigators design their own calibration curves not only to improve accuracy but also to understand the range(s) of highest error and to choose the optimal points within the expected sensing range for calibration. Since output and sensor nonlinearity depend on the experimental protocol (sensor type, interface shape and materials, sensor range in use, loading method, etc.), sensor behavior should be investigated for each different application.

  13. Decoding Accuracy in Supplementary Motor Cortex Correlates with Perceptual Sensitivity to Tactile Roughness

    PubMed Central

    Kim, Junsuk; Chung, Yoon Gi; Park, Jang-Yeon; Chung, Soon-Cheol; Wallraven, Christian; Bülthoff, Heinrich H.; Kim, Sung-Phil

    2015-01-01

    Perceptual sensitivity to tactile roughness varies across individuals for the same degree of roughness. A number of neurophysiological studies have investigated the neural substrates of tactile roughness perception, but the neural processing underlying the strong individual differences in perceptual roughness sensitivity remains unknown. In this study, we explored the human brain activation patterns associated with the behavioral discriminability of surface texture roughness using functional magnetic resonance imaging (fMRI). First, a whole-brain searchlight multi-voxel pattern analysis (MVPA) was used to find brain regions from which we could decode roughness information. The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP). Next, we evaluated the behavioral roughness discrimination sensitivity of each individual using the just-noticeable difference (JND) and correlated this with the decoding accuracy in each of the four regions. We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA. Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA. PMID:26067832

  14. Optimizing stepwise rotation of dodecahedron sound source to improve the accuracy of room acoustic measures.

    PubMed

    Martellotta, Francesco

    2013-09-01

    Dodecahedron sound sources are widely used for acoustical measurement purposes as they produce a good approximation of omnidirectional radiation. Evidence shows that such an assumption is acceptable only in the low-frequency range (namely below 1 kHz), while at higher frequencies sound radiation is far from being uniform. In order to improve the accuracy of acoustical measurements obtained from dodecahedron sources, international standard ISO 3382 suggests an averaging of results after a source rotation. This paper investigates the effects of such rotations, both in terms of variations in acoustical parameters and spatial distribution of sound reflections. Taking advantage of a spherical microphone array, the different reflection patterns were mapped as a function of source rotation, showing that some reflections may be considerably attenuated for different aiming directions. This paper investigates the concept of averaging results while changing rotation angles and the minimum number of rotations required to improve the accuracy of the average value. Results show that averages of three measurements carried out at 30° angular steps are closer to actual values and show much less fluctuation. In addition, an averaging of the directional intensity components of the selected responses stabilizes the spatial distribution of the reflections.

  15. An Integrated MEMS Gyroscope Array with Higher Accuracy Output.

    PubMed

    Chang, Honglong; Xue, Liang; Qin, Wei; Yuan, Guangmin; Yuan, Weizheng

    2008-04-28

    In this paper, an integrated MEMS gyroscope array method composed of two levels of optimal filtering was designed to improve the accuracy of gyroscopes. In the firstlevel filtering, several identical gyroscopes were combined through Kalman filtering into a single effective device, whose performance could surpass that of any individual sensor. The key of the performance improving lies in the optimal estimation of the random noise sources such as rate random walk and angular random walk for compensating the measurement values. Especially, the cross correlation between the noises from different gyroscopes of the same type was used to establish the system noise covariance matrix and the measurement noise covariance matrix for Kalman filtering to improve the performance further. Secondly, an integrated Kalman filter with six states was designed to further improve the accuracy with the aid of external sensors such as magnetometers and accelerometers in attitude determination. Experiments showed that three gyroscopes with a bias drift of 35 degree per hour could be combined into a virtual gyroscope with a drift of 1.07 degree per hour through the first-level filter, and the bias drift was reduced to 0.53 degree per hour after the second-level filtering. It proved that the proposed integrated MEMS gyroscope array is capable of improving the accuracy of the MEMS gyroscopes, which provides the possibility of using these low cost MEMS sensors in high-accuracy application areas.

  16. Relevance of intracellular polarity to accuracy of eukaryotic chemotaxis

    NASA Astrophysics Data System (ADS)

    Hiraiwa, Tetsuya; Nagamatsu, Akihiro; Akuzawa, Naohiro; Nishikawa, Masatoshi; Shibata, Tatsuo

    2014-10-01

    Eukaryotic chemotaxis is usually mediated by intracellular signals that tend to localize at the front or back of the cell. Such intracellular polarities frequently require no extracellular guidance cues, indicating that spontaneous polarization occurs in the signal network. Spontaneous polarization activity is considered relevant to the persistent motions in random cell migrations and chemotaxis. In this study, we propose a theoretical model that connects spontaneous intracellular polarity and motile ability in a chemoattractant solution. We demonstrate that the intracellular polarity can enhance the accuracy of chemotaxis. Chemotactic accuracy should also depend on chemoattractant concentration through the concentration-dependent correlation time in the polarity direction. Both the polarity correlation time and the chemotactic accuracy depend on the degree of responsiveness to the chemical gradient. We show that optimally accurate chemotaxis occurs at an intermediate responsiveness of intracellular polarity. Experimentally, we find that the persistence time of randomly migrating Dictyostelium cells depends on the chemoattractant concentration, as predicted by our theory. At the optimum responsiveness, this ameboid cell can enhance its chemotactic accuracy tenfold.

  17. Accuracy limit of rigid 3-point water models

    NASA Astrophysics Data System (ADS)

    Izadi, Saeed; Onufriev, Alexey V.

    2016-08-01

    Classical 3-point rigid water models are most widely used due to their computational efficiency. Recently, we introduced a new approach to constructing classical rigid water models [S. Izadi et al., J. Phys. Chem. Lett. 5, 3863 (2014)], which permits a virtually exhaustive search for globally optimal model parameters in the sub-space that is most relevant to the electrostatic properties of the water molecule in liquid phase. Here we apply the approach to develop a 3-point Optimal Point Charge (OPC3) water model. OPC3 is significantly more accurate than the commonly used water models of same class (TIP3P and SPCE) in reproducing a comprehensive set of liquid bulk properties, over a wide range of temperatures. Beyond bulk properties, we show that OPC3 predicts the intrinsic charge hydration asymmetry (CHA) of water — a characteristic dependence of hydration free energy on the sign of the solute charge — in very close agreement with experiment. Two other recent 3-point rigid water models, TIP3PFB and H2ODC, each developed by its own, completely different optimization method, approach the global accuracy optimum represented by OPC3 in both the parameter space and accuracy of bulk properties. Thus, we argue that an accuracy limit of practical 3-point rigid non-polarizable models has effectively been reached; remaining accuracy issues are discussed.

  18. Accuracy limit of rigid 3-point water models.

    PubMed

    Izadi, Saeed; Onufriev, Alexey V

    2016-08-21

    Classical 3-point rigid water models are most widely used due to their computational efficiency. Recently, we introduced a new approach to constructing classical rigid water models [S. Izadi et al., J. Phys. Chem. Lett. 5, 3863 (2014)], which permits a virtually exhaustive search for globally optimal model parameters in the sub-space that is most relevant to the electrostatic properties of the water molecule in liquid phase. Here we apply the approach to develop a 3-point Optimal Point Charge (OPC3) water model. OPC3 is significantly more accurate than the commonly used water models of same class (TIP3P and SPCE) in reproducing a comprehensive set of liquid bulk properties, over a wide range of temperatures. Beyond bulk properties, we show that OPC3 predicts the intrinsic charge hydration asymmetry (CHA) of water - a characteristic dependence of hydration free energy on the sign of the solute charge - in very close agreement with experiment. Two other recent 3-point rigid water models, TIP3PFB and H2ODC, each developed by its own, completely different optimization method, approach the global accuracy optimum represented by OPC3 in both the parameter space and accuracy of bulk properties. Thus, we argue that an accuracy limit of practical 3-point rigid non-polarizable models has effectively been reached; remaining accuracy issues are discussed.

  19. Relevance of intracellular polarity to accuracy of eukaryotic chemotaxis.

    PubMed

    Hiraiwa, Tetsuya; Nagamatsu, Akihiro; Akuzawa, Naohiro; Nishikawa, Masatoshi; Shibata, Tatsuo

    2014-08-14

    Eukaryotic chemotaxis is usually mediated by intracellular signals that tend to localize at the front or back of the cell. Such intracellular polarities frequently require no extracellular guidance cues, indicating that spontaneous polarization occurs in the signal network. Spontaneous polarization activity is considered relevant to the persistent motions in random cell migrations and chemotaxis. In this study, we propose a theoretical model that connects spontaneous intracellular polarity and motile ability in a chemoattractant solution. We demonstrate that the intracellular polarity can enhance the accuracy of chemotaxis. Chemotactic accuracy should also depend on chemoattractant concentration through the concentration-dependent correlation time in the polarity direction. Both the polarity correlation time and the chemotactic accuracy depend on the degree of responsiveness to the chemical gradient. We show that optimally accurate chemotaxis occurs at an intermediate responsiveness of intracellular polarity. Experimentally, we find that the persistence time of randomly migrating Dictyostelium cells depends on the chemoattractant concentration, as predicted by our theory. At the optimum responsiveness, this ameboid cell can enhance its chemotactic accuracy tenfold.

  20. Does Preoperative Measurement of Cerebral Blood Flow with Acetazolamide Challenge in Addition to Preoperative Measurement of Cerebral Blood Flow at the Resting State Increase the Predictive Accuracy of Development of Cerebral Hyperperfusion after Carotid Endarterectomy? Results from 500 Cases with Brain Perfusion Single-photon Emission Computed Tomography Study

    PubMed Central

    OSHIDA, Sotaro; OGASAWARA, Kuniaki; SAURA, Hiroaki; YOSHIDA, Koji; FUJIWARA, Shunro; KOJIMA, Daigo; KOBAYASHI, Masakazu; YOSHIDA, Kenji; KUBO, Yoshitaka; OGAWA, Akira

    2015-01-01

    The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[123I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using 123I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion. PMID:25746308

  1. Does preoperative measurement of cerebral blood flow with acetazolamide challenge in addition to preoperative measurement of cerebral blood flow at the resting state increase the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy? Results from 500 cases with brain perfusion single-photon emission computed tomography study.

    PubMed

    Oshida, Sotaro; Ogasawara, Kuniaki; Saura, Hiroaki; Yoshida, Koji; Fujiwara, Shunro; Kojima, Daigo; Kobayashi, Masakazu; Yoshida, Kenji; Kubo, Yoshitaka; Ogawa, Akira

    2015-01-01

    The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[(123)I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using (123)I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion.

  2. Measurement accuracies in band-limited extrapolation

    NASA Technical Reports Server (NTRS)

    Kritikos, H. N.

    1982-01-01

    The problem of numerical instability associated with extrapolation algorithms is addressed. An attempt is made to estimate the bounds for the acceptable errors and to place a ceiling on the measurement accuracy and computational accuracy needed for the extrapolation. It is shown that in band limited (or visible angle limited) extrapolation the larger effective aperture L' that can be realized from a finite aperture L by over sampling is a function of the accuracy of measurements. It is shown that for sampling in the interval L/b absolute value of xL, b1 the signal must be known within an error e sub N given by e sub N squared approximately = 1/4(2kL') cubed (e/8b L/L')(2kL') where L is the physical aperture, L' is the extrapolated aperture, and k = 2pi lambda.

  3. Increasing Accuracy and Increasing Tension in Ho

    NASA Astrophysics Data System (ADS)

    Freedman, Wendy L.

    2017-01-01

    The Hubble Constant, Ho, provides a measure of the current expansion rate of the universe. In recent decades, there has been a huge increase in the accuracy with which extragalactic distances, and hence Ho, can be measured. While the historical factor-of-two uncertainty in Ho has been resolved, a new discrepancy has arisen between the values of Ho measured in the local universe, and that estimated from cosmic microwave background measurements, assuming a Lambda cold dark matter model. I will review the advances that have led to the increase in accuracy in measurements of Ho, as well as describe exciting future prospects with the James Webb Space Telescope (JWST) and Gaia, which will make it feasible to measure extragalactic distances at percent-level accuracy in the next decade.

  4. First accuracy evaluation of NIST-F2

    NASA Astrophysics Data System (ADS)

    Heavner, Thomas P.; Donley, Elizabeth A.; Levi, Filippo; Costanzo, Giovanni; Parker, Thomas E.; Shirley, Jon H.; Ashby, Neil; Barlow, Stephan; Jefferts, S. R.

    2014-06-01

    We report the first accuracy evaluation of NIST-F2, a second-generation laser-cooled caesium fountain primary standard developed at the National Institute of Standards and Technology (NIST) with a cryogenic (liquid nitrogen) microwave cavity and flight region. The 80 K atom interrogation environment reduces the uncertainty due to the blackbody radiation shift by more than a factor of 50. Also, the Ramsey microwave cavity exhibits a high quality factor (>50 000) at this low temperature, resulting in a reduced distributed cavity phase shift. NIST-F2 has undergone many tests and improvements since we first began operation in 2008. In the last few years NIST-F2 has been compared against a NIST maser time scale and NIST-F1 (the US primary frequency standard) as part of in-house accuracy evaluations. We report the results of nine in-house comparisons since 2010 with a focus on the most recent accuracy evaluation. This paper discusses the design of the physics package, the laser and optics systems and the accuracy evaluation methods. The type B fractional uncertainty of NIST-F2 is shown to be 0.11 × 10-15 and is dominated by microwave amplitude dependent effects. The most recent evaluation (August 2013) had a statistical (type A) fractional uncertainty of 0.44 × 10-15.

  5. Interoception and symptom reporting: disentangling accuracy and bias

    PubMed Central

    Petersen, Sibylle; Van Staeyen, Ken; Vögele, Claus; von Leupoldt, Andreas; Van den Bergh, Omer

    2015-01-01

    Anxiety and anxiety sensitivity are positively related to accuracy in the perception of bodily sensations. At the same time, research consistently reports that these traits are positively related to bias, resulting in the report of more and more intense symptoms that poorly correspond with physiological dysfunction. The aim of this study was to test the relationship of accuracy and bias in interoception. Furthermore, we tested the impact of individual differences in negative affect and symptom report in daily life on interoceptive accuracy and bias. Individuals higher in symptom report in daily life and negative affect were marginally more accurate in an interoceptive classification task in which participants were asked to identify different respiratory stimuli (inducing breathing effort) as belonging to a high or low intensity category. At the same time, bias in overestimating intensity of stimuli was significantly increased in participants higher in symptom report and negative affect, but only for more ambiguous stimuli. Results illustrate that interoceptive accuracy and bias need to be considered independently to understand their interaction with psychological factors and to disentangle (mis)perception of bodily sensations from liberal or conservative perceptual decision strategies. PMID:26089810

  6. Accuracy verification of the Lynx Mobile Mapper system

    NASA Astrophysics Data System (ADS)

    Puente, I.; González-Jorge, H.; Riveiro, B.; Arias, P.

    2013-02-01

    LiDAR technology is one of the most effective and reliable means of data collection. Given the increasing use of LiDAR data for close range metrology applications such as deformation monitoring and infrastructure inspection, it becomes necessary to test the relative accuracy, boresight calibration of both LiDAR sensors and performance of navigation solution (or absolute accuracy) of any mobile laser scanning system employed for this purpose. Therefore, the paper's primary contribution is a set of tests for the characterization and evaluation of any mobile laser scanning system based on two LiDAR sensors. We present experimental results of the Lynx Mobile Mapper system from Optech Inc. Employing a low-cost calibration standard, we demonstrated sub-cm accuracy of targets at distances up to 10 m. Also, we introduce boresighting results derived from the Lynx system. Moreover, the global system's accuracy is tested with a series of rigorous experiments operated at a maximum scan frequency of 200 Hz, pulse repetition frequency of 500 kHz per sensor and a 360° scanning field of view. Assuring good GPS conditions, we proved a good global performance of the system, which makes it suitable for very accurate applications.

  7. Evaluation of structural and thermophysical effects on the measurement accuracy of deep body thermometers based on dual-heat-flux method.

    PubMed

    Huang, Ming; Tamura, Toshiyo; Chen, Wenxi; Kanaya, Shigehiko

    2015-01-01

    To help pave a path toward the practical use of continuous unconstrained noninvasive deep body temperature measurement, this study aims to evaluate the structural and thermophysical effects on measurement accuracy for the dual-heat-flux method (DHFM). By considering the thermometer's height, radius, conductivity, density and specific heat as variables affecting the accuracy of DHFM measurement, we investigated the relationship between those variables and accuracy using 3-D models based on finite element method. The results of our simulation study show that accuracy is proportional to the radius but inversely proportional to the thickness of the thermometer when the radius is less than 30.0mm, and is also inversely proportional to the heat conductivity of the heat insulator inside the thermometer. The insights from this study would help to build a guideline for design, fabrication and optimization of DHFM-based thermometers, as well as their practical use.

  8. The accuracy of Halley's cometary orbits

    NASA Astrophysics Data System (ADS)

    Hughes, D. W.

    The accuracy of a scientific computation depends in the main on the data fed in and the analysis method used. This statement is certainly true of Edmond Halley's cometary orbit work. Considering the 420 comets that had been seen before Halley's era of orbital calculation (1695 - 1702) only 24, according to him, had been observed well enough for their orbits to be calculated. Two questions are considered in this paper. Do all the orbits listed by Halley have the same accuracy? and, secondly, how accurate was Halley's method of calculation?

  9. Field Accuracy Test of Rpas Photogrammetry

    NASA Astrophysics Data System (ADS)

    Barry, P.; Coakley, R.

    2013-08-01

    Baseline Surveys Ltd is a company which specialises in the supply of accurate geospatial data, such as cadastral, topographic and engineering survey data to commercial and government bodies. Baseline Surveys Ltd invested in aerial drone photogrammetric technology and had a requirement to establish the spatial accuracy of the geographic data derived from our unmanned aerial vehicle (UAV) photogrammetry before marketing our new aerial mapping service. Having supplied the construction industry with survey data for over 20 years, we felt that is was crucial for our clients to clearly understand the accuracy of our photogrammetry so they can safely make informed spatial decisions, within the known accuracy limitations of our data. This information would also inform us on how and where UAV photogrammetry can be utilised. What we wanted to find out was the actual accuracy that can be reliably achieved using a UAV to collect data under field conditions throughout a 2 Ha site. We flew a UAV over the test area in a "lawnmower track" pattern with an 80% front and 80% side overlap; we placed 45 ground markers as check points and surveyed them in using network Real Time Kinematic Global Positioning System (RTK GPS). We specifically designed the ground markers to meet our accuracy needs. We established 10 separate ground markers as control points and inputted these into our photo modelling software, Agisoft PhotoScan. The remaining GPS coordinated check point data were added later in ArcMap to the completed orthomosaic and digital elevation model so we could accurately compare the UAV photogrammetry XYZ data with the RTK GPS XYZ data at highly reliable common points. The accuracy we achieved throughout the 45 check points was 95% reliably within 41 mm horizontally and 68 mm vertically and with an 11.7 mm ground sample distance taken from a flight altitude above ground level of 90 m.The area covered by one image was 70.2 m × 46.4 m, which equals 0.325 Ha. This finding has shown

  10. Estimation and Accuracy after Model Selection

    PubMed Central

    Efron, Bradley

    2013-01-01

    Classical statistical theory ignores model selection in assessing estimation accuracy. Here we consider bootstrap methods for computing standard errors and confidence intervals that take model selection into account. The methodology involves bagging, also known as bootstrap smoothing, to tame the erratic discontinuities of selection-based estimators. A useful new formula for the accuracy of bagging then provides standard errors for the smoothed estimators. Two examples, nonparametric and parametric, are carried through in detail: a regression model where the choice of degree (linear, quadratic, cubic, …) is determined by the Cp criterion, and a Lasso-based estimation problem. PMID:25346558

  11. Predictive accuracy in the neuroprediction of rearrest

    PubMed Central

    Aharoni, Eyal; Mallett, Joshua; Vincent, Gina M.; Harenski, Carla L.; Calhoun, Vince D.; Sinnott-Armstrong, Walter; Gazzaniga, Michael S.; Kiehl, Kent A.

    2014-01-01

    A recently published study by the present authors (Aharoni et al., 2013) reported evidence that functional changes in the anterior cingulate cortex (ACC) within a sample of 96 criminal offenders who were engaged in a Go/No-Go impulse control task significantly predicted their rearrest following release from prison. In an extended analysis, we use discrimination and calibration techniques to test the accuracy of these predictions relative to more traditional models and their ability to generalize to new observations in both full and reduced models. Modest to strong discrimination and calibration accuracy were found, providing additional support for the utility of neurobiological measures in predicting rearrest. PMID:24720689

  12. Final Technical Report: Increasing Prediction Accuracy.

    SciTech Connect

    King, Bruce Hardison; Hansen, Clifford; Stein, Joshua

    2015-12-01

    PV performance models are used to quantify the value of PV plants in a given location. They combine the performance characteristics of the system, the measured or predicted irradiance and weather at a site, and the system configuration and design into a prediction of the amount of energy that will be produced by a PV system. These predictions must be as accurate as possible in order for finance charges to be minimized. Higher accuracy equals lower project risk. The Increasing Prediction Accuracy project at Sandia focuses on quantifying and reducing uncertainties in PV system performance models.

  13. Accuracy of quantitative visual soil assessment

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Maricke; Heuvelink, Gerard; Stoorvogel, Jetse; Wallinga, Jakob; de Boer, Imke; van Dam, Jos; van Essen, Everhard; Moolenaar, Simon; Verhoeven, Frank; Stoof, Cathelijne

    2016-04-01

    Visual soil assessment (VSA) is a method to assess soil quality visually, when standing in the field. VSA is increasingly used by farmers, farm organisations and companies, because it is rapid and cost-effective, and because looking at soil provides understanding about soil functioning. Often VSA is regarded as subjective, so there is a need to verify VSA. Also, many VSAs have not been fine-tuned for contrasting soil types. This could lead to wrong interpretation of soil quality and soil functioning when contrasting sites are compared to each other. We wanted to assess accuracy of VSA, while taking into account soil type. The first objective was to test whether quantitative visual field observations, which form the basis in many VSAs, could be validated with standardized field or laboratory measurements. The second objective was to assess whether quantitative visual field observations are reproducible, when used by observers with contrasting backgrounds. For the validation study, we made quantitative visual observations at 26 cattle farms. Farms were located at sand, clay and peat soils in the North Friesian Woodlands, the Netherlands. Quantitative visual observations evaluated were grass cover, number of biopores, number of roots, soil colour, soil structure, number of earthworms, number of gley mottles and soil compaction. Linear regression analysis showed that four out of eight quantitative visual observations could be well validated with standardized field or laboratory measurements. The following quantitative visual observations correlated well with standardized field or laboratory measurements: grass cover with classified images of surface cover; number of roots with root dry weight; amount of large structure elements with mean weight diameter; and soil colour with soil organic matter content. Correlation coefficients were greater than 0.3, from which half of the correlations were significant. For the reproducibility study, a group of 9 soil scientists and 7

  14. Accuracy assessment of airborne photogrammetrically derived high-resolution digital elevation models in a high mountain environment

    NASA Astrophysics Data System (ADS)

    Müller, Johann; Gärtner-Roer, Isabelle; Thee, Patrick; Ginzler, Christian

    2014-12-01

    High-resolution digital elevation models (DEMs) generated by airborne remote sensing are frequently used to analyze landform structures (monotemporal) and geomorphological processes (multitemporal) in remote areas or areas of extreme terrain. In order to assess and quantify such structures and processes it is necessary to know the absolute accuracy of the available DEMs. This study assesses the absolute vertical accuracy of DEMs generated by the High Resolution Stereo Camera-Airborne (HRSC-A), the Leica Airborne Digital Sensors 40/80 (ADS40 and ADS80) and the analogue camera system RC30. The study area is located in the Turtmann valley, Valais, Switzerland, a glacially and periglacially formed hanging valley stretching from 2400 m to 3300 m a.s.l. The photogrammetrically derived DEMs are evaluated against geodetic field measurements and an airborne laser scan (ALS). Traditional and robust global and local accuracy measurements are used to describe the vertical quality of the DEMs, which show a non Gaussian distribution of errors. The results show that all four sensor systems produce DEMs with similar accuracy despite their different setups and generations. The ADS40 and ADS80 (both with a ground sampling distance of 0.50 m) generate the most accurate DEMs in complex high mountain areas with a RMSE of 0.8 m and NMAD of 0.6 m They also show the highest accuracy relating to flying height (0.14‰). The pushbroom scanning system HRSC-A produces a RMSE of 1.03 m and a NMAD of 0.83 m (0.21‰ accuracy of the flying height and 10 times the ground sampling distance). The analogue camera system RC30 produces DEMs with a vertical accuracy of 1.30 m RMSE and 0.83 m NMAD (0.17‰ accuracy of the flying height and two times the ground sampling distance). It is also shown that the performance of the DEMs strongly depends on the inclination of the terrain. The RMSE of areas up to an inclination <40° is better than 1 m. In more inclined areas the error and outlier occurrence

  15. Accuracy of intraoral and extraoral digital data acquisition for dental restorations

    PubMed Central

    Rudolph, Heike; Salmen, Harald; Moldan, Matthias; Kuhn, Katharina; Sichwardt, Viktor; Wöstmann, Bernd; Luthardt, Ralph Gunnar

    2016-01-01

    ABSTRACT The computer-aided design (CAD) and computer-aided manufacturing (CAM) process chain for dental restorations starts with taking an impression of the clinical situation. For this purpose, either extraoral digitization of gypsum models or intraoral digitization can be used. Despite the increasing use of dental digitizing systems, there are only few studies on their accuracy. Objective This study compared the accuracy of various intraoral and extraoral digitizing systems for dental CAD/CAM technology. Material and Methods An experimental setup for three-dimensional analysis based on 2 prepared ceramic master dies and their corresponding virtual CAD-models was used to assess the accuracy of 10 extraoral and 4 intraoral optical non-contact dental digitizing systems. Depending on the clinical procedure, 10 optical measurements of either 10 duplicate gypsum dies (extraoral digitizing) or directly of the ceramic master dies (intraoral digitizing) were made and compared with the corresponding CAD-models. Results The digitizing systems showed differences in accuracy. However, all topical systems were well within the benchmark of ±20 µm. These results apply to single tooth measurements. Conclusions Study results are limited, since only single teeth were used for comparison. The different preparations represent various angles and steep and parallel opposing tooth surfaces (incisors). For most digitizing systems, the latter are generally the most difficult to capture. Using CAD/CAM technologies, the preparation angles should not be too steep to reduce digitizing errors. Older systems might be limited to a certain height or taper of the prepared tooth, whereas newer systems (extraoral as well as intraoral digitization) do not have these limitations. PMID:27008261

  16. Clinical accuracy of ExacTrac intracranial frameless stereotactic system

    SciTech Connect

    Ackerly, T.; Lancaster, C. M.; Geso, M.; Roxby, K. J.

    2011-09-15

    Purpose: In this paper, the authors assess the accuracy of the Brainlab ExacTrac system for frameless intracranial stereotactic treatments in clinical practice. Methods: They recorded couch angle and image fusion results (comprising lateral, longitudinal, and vertical shifts, and rotation corrections about these axes) for 109 stereotactic radiosurgery and 166 stereotactic radiotherapy patient treatments. Frameless stereotactic treatments involve iterative 6D image fusion corrections applied until the results conform to customizable pass criteria, theirs being 0.7 mm and 0.5 deg. for each axis. The planning CT slice thickness was 1.25 mm. It has been reported in the literature that the CT slices' thickness impacts the accuracy of localization to bony anatomy. The principle of invariance with respect to patient orientation was used to determine spatial accuracy. Results: The data for radiosurgery comprised 927 image pairs, of which 532 passed (pass ratio of 57.4%). The data for radiotherapy comprised 15983 image pairs, of which 10 050 passed (pass ratio of 62.9%). For stereotactic radiotherapy, the combined uncertainty of ExacTrac calibration, image fusion, and intrafraction motion was (95% confidence interval) 0.290-0.302 and 0.306-0.319 mm in the longitudinal and lateral axes, respectively. The combined uncertainty of image fusion and intrafraction motion in the anterior-posterior coordinates was 0.174-0.182 mm. For stereotactic radiosurgery, the equivalent ranges are 0.323-0.393, 0.337-0.409, and 0.231-0.281 mm. The overall spatial accuracy was 1.24 mm for stereotactic radiotherapy (SRT) and 1.35 mm for stereotactic radiosurgery (SRS). Conclusions: The ExacTrac intracranial frameless stereotactic system spatial accuracy is adequate for clinical practice, and with the same pass criteria, SRT is more accurate than SRS. They now use frameless stereotaxy exclusively at their center.

  17. The accuracy of the Edinburgh diplopia diagnostic algorithm.

    PubMed

    Butler, L; Yap, T; Wright, M

    2016-06-01

    PurposeTo assess the diagnostic accuracy of the Edinburgh diplopia diagnostic algorithm.MethodsThis was a prospective study. Details of consecutive patients referred to ophthalmology clinics at Falkirk Community Hospital and Princess Alexandra Eye Pavilion, Edinburgh, with double vision were collected by the clinician first seeing the patient and passed to the investigators. The investigators then assessed the patient using the algorithm. An assessment of the degree of concordance between the 'algorithm assisted' diagnosis and the 'gold standard' diagnosis, made by a consultant ophthalmologist was then carried out. The accuracy of the pre-algorithm diagnosis made by the referrer was also noted.ResultsAll patients referred with diplopia were eligible for inclusion. Fifty-one patients were assessed; six were excluded. The pre-algorithm accuracy of referrers was 24% (10/41). The algorithm assisted diagnosis was correct 82% (37/45) of the time. It correctly diagnosed: cranial nerve (CN) III palsy in 6/6, CN IV palsy in 7/8, CN VI palsy in 12/12, internuclear ophthalmoplegia in 4/4, restrictive myopathy in 4/4, media opacity in 1/1, and blurred vision in 3/3. The algorithm assisted diagnosis was wrong in 18% (8/45) of the patients.ConclusionsThe baseline diagnostic accuracy of non-ophthalmologists rose from 24 to 82% when patients were assessed using the algorithm. The improvement in the diagnostic accuracy resulting from the use of the algorithm would, hopefully, result in more accurate triage of patients with diplopia that are referred to the hospital eye service. We hope we have demonstrated its potential as a learning tool for inexperienced clinicians.

  18. Determination of elemental composition of volatile organic compounds from Chinese rose oil by spectral accuracy and mass accuracy.

    PubMed

    Zhou, Wei; Zhang, Yaheng; Xu, Hongliang; Gu, Ming

    2011-10-30

    Elemental composition determination of volatile organic compounds through high mass accuracy and isotope pattern matching could not be routinely achieved with a unit-mass resolution mass spectrometer until the recent development of the comprehensive instrument line-shape calibration technology. Through this unique technology, both m/z values and mass spectral peak shapes are calibrated simultaneously. Of fundamental importance is that calibrated mass spectra have symmetric and mathematically known peak shapes, which makes it possible to deconvolute overlapped monoisotopes and their (13)C-isotope peaks and achieve accurate mass measurements. The key experimental requirements for the measurements are to acquire true raw data in a profile or continuum mode with the acquisition threshold set to zero. A total of 13 ions from Chinese rose oil were analyzed with internal calibration. Most of the ions produced high mass accuracy of better than 5 mDa and high spectral accuracy of better than 99%. These results allow five tested ions to be identified with unique elemental compositions and the other eight ions to be determined as a top match from multiple candidates based on spectral accuracy. One of them, a coeluted component (Nerol) with m/z 154, could not be identified by conventional GC/MS (gas chromatography/mass spectrometry) and library search. Such effective determination for elemental compositions of the volatile organic compounds with a unit-mass resolution quadrupole system is obviously attributed to the significant improvement of mass accuracy. More importantly, high spectral accuracy available through the instrument line-shape calibration enables highly accurate isotope pattern recognition for unknown identification.

  19. Effects of LiDAR point density, sampling size and height threshold on estimation accuracy of crop biophysical parameters.

    PubMed

    Luo, Shezhou; Chen, Jing M; Wang, Cheng; Xi, Xiaohuan; Zeng, Hongcheng; Peng, Dailiang; Li, Dong

    2016-05-30

    Vegetation leaf area index (LAI), height, and aboveground biomass are key biophysical parameters. Corn is an important and globally distributed crop, and reliable estimations of these parameters are essential for corn yield forecasting, health monitoring and ecosystem modeling. Light Detection and Ranging (LiDAR) is considered an effective technology for estimating vegetation biophysical parameters. However, the estimation accuracies of these parameters are affected by multiple factors. In this study, we first estimated corn LAI, height and biomass (R2 = 0.80, 0.874 and 0.838, respectively) using the original LiDAR data (7.32 points/m2), and the results showed that LiDAR data could accurately estimate these biophysical parameters. Second, comprehensive research was conducted on the effects of LiDAR point density, sampling size and height threshold on the estimation accuracy of LAI, height and biomass. Our findings indicated that LiDAR point density had an important effect on the estimation accuracy for vegetation biophysical parameters, however, high point density did not always produce highly accurate estimates, and reduced point density could deliver reasonable estimation results. Furthermore, the results showed that sampling size and height threshold were additional key factors that affect the estimation accuracy of biophysical parameters. Therefore, the optimal sampling size and the height threshold should be determined to improve the estimation accuracy of biophysical parameters. Our results also implied that a higher LiDAR point density, larger sampling size and height threshold were required to obtain accurate corn LAI estimation when compared with height and biomass estimations. In general, our results provide valuable guidance for LiDAR data acquisition and estimation of vegetation biophysical parameters using LiDAR data.

  20. The effect of individual or group guidelines on the calibration accuracy of high school biology students

    NASA Astrophysics Data System (ADS)

    Walck, Camilla C.

    The effect of individual or group guidelines on the calibration accuracy of high school biology students was investigated. The study was conducted with 102 International Baccalaureate Middle Years Program biology students in a public school setting. The study was carried out over three testing occasions. Students worked in group or individual settings with and without calibration guidelines. Four intact classes were randomly assigned to one of four conditions: groups calibrating without guidelines; groups calibrating with guidelines; individuals calibrating without guidelines; individuals calibrating with guidelines. The students participated in the calibration activities one block before they actually took each of the three tests. On the day of each test, immediately before taking the test, each student made predictions as to what they thought they would score on the test. Immediately after taking the test each student made postdictions on what they thought they scored on the test. Calibration accuracy was determined by calculating the difference between prediction and postdiction scores and the actual test score achieved. The results indicated that students who calibrated in groups showed trends of more accurate calibration predictions. Although one testing intervention showed significant results for postdiction accuracy, the other two testing interventions showed varied results. Students who calibrated in groups achieved higher scores on tests than did students who calibrated individually. In addition, guidelines were shown to be a significant factor in increasing achievement for students who calibrated individually. For students calibrating in groups guidelines had little impact. The results support the need for more research in metacognition and calibration techniques in order to improve student academic success.

  1. Sampling issues affecting accuracy of likelihood-based classification using genetical data

    USGS Publications Warehouse

    Guinand, B.; Scribner, K.T.; Topchy, A.; Page, K.S.; Punch, W.; Burnham-Curtis, M. K.

    2004-01-01

    We demonstrate the effectiveness of a genetic algorithm for discovering multi-locus combinations that provide accurate individual assignment decisions and estimates of mixture composition based on likelihood classification. Using simulated data representing different levels of inter-population differentiation (Fst ~ 0.01 and 0.10), genetic diversities (four or eight alleles per locus), and population sizes (20, 40, 100 individuals in baseline populations), we show that subsets of loci can be identified that provide comparable levels of accuracy in classification decisions relative to entire multi-locus data sets, where 5, 10, or 20 loci were considered. Microsatellite data sets from hatchery strains of lake trout, Salvelinus namaycush, representing a comparable range of inter-population levels of differentiation in allele frequencies confirmed simulation results. For both simulated and empirical data sets, assignment accuracy was achieved using fewer loci (e.g., three or four loci out of eight for empirical lake trout studies). Simulation results were used to investigate properties of the 'leave-one-out' (L1O) method for estimating assignment error rates. Accuracy of population assignments based on L1O methods should be viewed with caution under certain conditions, particularly when baseline population sample sizes are low (<50).

  2. Accuracy of femur reconstruction from sparse geometric data using a statistical shape model.

    PubMed

    Zhang, Ju; Besier, Thor F

    2017-04-01

    Sparse geometric information from limited field-of-view medical images is often used to reconstruct the femur in biomechanical models of the hip and knee. However, the full femur geometry is needed to establish boundary conditions such as muscle attachment sites and joint axes which define the orientation of joint loads. Statistical shape models have been used to estimate the geometry of the full femur from varying amounts of sparse geometric information. However, the effect that different amounts of sparse data have on reconstruction accuracy has not been systematically assessed. In this study, we compared shape model and linear scaling reconstruction of the full femur surface from varying proportions of proximal and distal partial femur geometry in combination with morphometric and landmark data. We quantified reconstruction error in terms of surface-to-surface error as well as deviations in the reconstructed femur's anatomical coordinate system which is important for biomechanical models. Using a partial proximal femur surface, mean shape model-based reconstruction surface error was 1.8 mm with 0.15° or less anatomic axis error, compared to 19.1 mm and 2.7-5.6° for linear scaling. Similar results were found when using a partial distal surface. However, varying amounts of proximal or distal partial surface data had a negligible effect on reconstruction accuracy. Our results show that given an appropriate set of sparse geometric data, a shape model can reconstruct full femur geometry with far greater accuracy than simple scaling.

  3. Effect of pre-flaring and file size on the accuracy of two electronic apex locators

    PubMed Central

    BRITO-JÚNIOR, Manoel; CAMILO, Carla Cristina; MOREIRA-JÚNIOR, Gil; PECORA, Jesus Djalma; SOUSA-NETO, Manoel Damião

    2012-01-01

    Objective This ex vivo study evaluated the effect of pre-flaring and file size on the accuracy of the Root ZX and Novapex electronic apex locators (EALs). Material and methods The actual working length (WL) was set 1 mm short of the apical foramen in the palatal root canals of 24 extracted maxillary molars. The teeth were embedded in an alginate mold, and two examiners performed the electronic measurements using #10, #15, and #20 K-files. The files were inserted into the root canals until the "0.0" or ''APEX'' signals were observed on the LED or display screens for the Novapex and Root ZX, respectively, retracting to the 1.0 mark. The measurements were repeated after the pre-flaring using the S1 and SX Pro-Taper instruments. Two measurements were performed for each condition and the means were used. Intra-class correlation coefficients (ICCs) were calculated to verify the intra- and inter-examiner agreement. The mean differences between the WL and electronic length values were analyzed by the three-way ANOVA test (p<0.05). Results ICCs were high (>0.8) and the results demonstrated a similar accuracy for both EALs (p>0.05). Statistically significant accurate measurements were verified in the pre-flared canals, except for the Novapex using a #20 K-file. Conclusions The tested EALs showed acceptable accuracy, whereas the pre-flaring procedure revealed a more significant effect than the used file size. PMID:23138740

  4. Accuracy and repeatability of a new method for measuring facet loads in the lumbar spine.

    PubMed

    Wilson, Derek C; Niosi, Christina A; Zhu, Qingan A; Oxland, Thomas R; Wilson, David R

    2006-01-01

    We assessed the repeatability and accuracy of a relatively new, resistance-based sensor (Tekscan 6900) for measuring lumbar spine facet loads, pressures, and contact areas in cadaver specimens. Repeatability of measurements in the natural facet joint was determined for five trials of four specimens loaded in pure moment (+/- 7.5 N m) flexibility tests in axial rotation and flexion-extension. Accuracy of load measurements in four joints was assessed by applying known compressive loads of 25, 50, and 100 N to the natural facet joint in a materials testing machine and comparing the known applied load to the measured load. Measurements of load were obtained using two different calibration approaches: linear and two-point calibrations. Repeatability for force, pressure, and area (average of standard deviation as a percentage of the mean for all trials over all specimens) was 4-6% for axial rotation and 7-10% for extension. Peak resultant force in axial rotation was 30% smaller when calculated using the linear calibration method. The Tekscan sensor overestimated the applied force by 18 +/- 9% (mean+/-standard deviation), 35 +/- 7% and 50 +/- 9% for compressive loads of 100, 50, and 25 N, respectively. The two-point method overestimated the loads by 35 +/- 16%, 45 +/- 7%, and 56 +/- 10% for the same three loads. Our results show that the Tekscan sensor is repeatable. However, the sensor measurement range is not optimal for the small loads transmitted by the facets and measurement accuracy is highly dependent on calibration protocol.

  5. Accuracy improvement capability of advanced projectile based on course correction fuze concept.

    PubMed

    Elsaadany, Ahmed; Wen-jun, Yi

    2014-01-01

    Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

  6. Accuracy Improvement Capability of Advanced Projectile Based on Course Correction Fuze Concept

    PubMed Central

    Elsaadany, Ahmed; Wen-jun, Yi

    2014-01-01

    Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion. PMID:25097873

  7. Accuracy potentials for large space antenna reflectors with passive structure

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1982-01-01

    Analytical results indicate that a careful selection of materials and truss design, combined with accurate manufacturing techniques, can result in very accurate surfaces for large space antennas. The purpose of this paper is to examine these relationships for various types of structural configurations. Comparisons are made of the accuracy achievable by truss- and dome-type structures for a wide range of diameter and focal length of the antenna and wavelength of the radiated signal.

  8. Human platelet sulfotransferase shows seasonal rhythms.

    PubMed

    Marazziti, D; Palego, L; Mazzanti, C; Silvestri, S; Cassano, G B

    1995-04-01

    Our study aimed to investigate the possible presence of seasonal changes in platelet phenolsulfotransferase (ST) in a group of 20 healthy, drug-free subjects of both sexes between 24 and 37 years of age. Blood samples were taken four times a year in the period immediately following the equinoxes and the solstices. The results showed that both Sts underwent seasonal changes: the lowest values were found in autumn and in winter, and the highest in the summer. A positive correlation between the two STs and the length of the photoperiod was observed in winter whereas in the spring we detected a negative correlation between the TL ST and the photoperiod length. Future studies should clarify whether platelet ST of patients with mood disorders shows a similar seasonality.

  9. Demographic corrections appear to compromise classification accuracy for severely skewed cognitive tests.

    PubMed

    O'Connell, Megan E; Tuokko, Holly; Kadlec, Helena

    2011-04-01

    Demographic corrections for cognitive tests should improve classification accuracy by reducing age or education biases, but empirical support has been equivocal. Using a simulation procedure, we show that creating moderate or extreme skewness in cognitive tests compromises the classification accuracy of demographic corrections, findings that appear replicated within clinical data for the few neuropsychological test scores with an extreme degree of skew. For most neuropsychological tests, the dementia classification accuracy of raw and demographically corrected scores was equivalent. These findings suggest that the dementia classification accuracy of demographic corrections is robust to slight degrees of skew (i.e., skewness <1.5).

  10. Modeling versus accuracy in EEG and MEG data

    SciTech Connect

    Mosher, J.C.; Huang, M.; Leahy, R.M.; Spencer, M.E.

    1997-07-30

    The widespread availability of high-resolution anatomical information has placed a greater emphasis on accurate electroencephalography and magnetoencephalography (collectively, E/MEG) modeling. A more accurate representation of the cortex, inner skull surface, outer skull surface, and scalp should lead to a more accurate forward model and hence improve inverse modeling efforts. The authors examine a few topics in this paper that highlight some of the problems of forward modeling, then discuss the impacts these results have on the inverse problem. The authors begin by assuming a perfect head model, that of the sphere, then show the lower bounds on localization accuracy of dipoles within this perfect forward model. For more realistic anatomy, the boundary element method (BEM) is a common numerical technique for solving the boundary integral equations. For a three-layer BEM, the computational requirements can be too intensive for many inverse techniques, so they examine a few simplifications. They quantify errors in generating this forward model by defining a regularized percentage error metric. The authors then apply this metric to a single layer boundary element solution, a multiple sphere approach, and the common single sphere model. They conclude with an MEG localization demonstration on a novel experimental human phantom, using both BEM and multiple spheres.

  11. On evaluation of depth accuracy in consumer depth sensors

    NASA Astrophysics Data System (ADS)

    Abd Aziz, Azim Zaliha; Wei, Hong; Ferryman, James

    2015-12-01

    This paper presents an experimental study of different depth sensors. The aim is to answer the question, whether these sensors give accurate data for general depth image analysis. The study examines the depth accuracy between three popularly used depth sensors; ASUS Xtion Prolive, Kinect Xbox 360 and Kinect for Windows v2. The main attention is to study on the stability of pixels in the depth image captured at several different sensor-object distances by measuring the depth returned by the sensors within specified time intervals. The experimental results show that the fluctuation (mm) of the random selected pixels within the target area, increases with increasing distance to the sensor, especially on the Kinect for Xbox 360 and the Asus Xtion Prolive. Both of these sensors provide pixels fluctuation between 20mm and 30mm at a sensor-object distance beyond 1500mm. However, the pixel's stability of the Kinect for Windows v2 not affected much with the distance between the sensor and the object. The maximum fluctuation for all the selected pixels of Kinect for Windows v2 is approximately 5mm at sensor-object distance of between 800mm and 3000mm. Therefore, in the optimal distance, the best stability achieved.

  12. Accuracy Improvement for Predicting Parkinson’s Disease Progression

    PubMed Central

    Nilashi, Mehrbakhsh; Ibrahim, Othman; Ahani, Ali

    2016-01-01

    Parkinson’s disease (PD) is a member of a larger group of neuromotor diseases marked by the progressive death of dopamineproducing cells in the brain. Providing computational tools for Parkinson disease using a set of data that contains medical information is very desirable for alleviating the symptoms that can help the amount of people who want to discover the risk of disease at an early stage. This paper proposes a new hybrid intelligent system for the prediction of PD progression using noise removal, clustering and prediction methods. Principal Component Analysis (PCA) and Expectation Maximization (EM) are respectively employed to address the multi-collinearity problems in the experimental datasets and clustering the data. We then apply Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Regression (SVR) for prediction of PD progression. Experimental results on public Parkinson’s datasets show that the proposed method remarkably improves the accuracy of prediction of PD progression. The hybrid intelligent system can assist medical practitioners in the healthcare practice for early detection of Parkinson disease. PMID:27686748

  13. Innovative Solutions for Pulsed Wind Lidar Accuracy in Complex Terrain

    NASA Astrophysics Data System (ADS)

    Boquet, M.

    2010-12-01

    Accuracy of Lidar remote sensors for wind energy has been previously reported. Coherent Doppler lidars have shown very high correlation with calibrated cup anemometers in flat terrain, both onshore and offshore. However, in more complex terrain, not only more turbulent air flow but also loss of flow homogeneity occurs, and remote sensors measurement process needs to be closely examined. We compare and simulate cup’s point and lidar’s volume measurements to understand and explain for the two sensor’s response. We emphasize the main error term in the horizontal and vertical wind speed retrieval. Geometrical optimizations of pulsed Lidar measurement process are also investigated to get more reliable wind speed estimations, such as finding the right cone angle to reduce the error. We show our conclusions and results of the CFD simulation performed on a Spanish complex terrain case. We see that there is at least one possibility to strongly reduce the relative error between Lidar and anemometer measurements. Indeed, accessing to the vertical wind speed variations leads to a considerable improvement in the linear correlation and dispersion.

  14. [A New Method to Decline the SWC Effect on the Accuracy for Monitoring SOM with Hyperspectral Technology].

    PubMed

    Wang, Chao; Feng, Mei-chen; Yang, Wu-de; Xiao, Lu-jie; Li, Guang-xin; Zhao, Jia-jia; Ren, Peng

    2015-12-01

    Soil organic matter (SOM) is one of the most important indexes to reflect the soil fertility, and soil moisture is a main factor to limit the application of hyperspectral technology in monitoring soil attributes. To study the effect of soil moisture on the accuracy for monitoring SOM with hyperspectral remote sensing and monitor the SOM quickly and accurately, SOM, soil water content (SWC) and soil spectrum for 151 natural soil samples in winter wheat field were measured and the soil samples were classified with the method of traditional classification of SWC and Normalized Difference Soil Moisture Index (NSMI) based on the hyperspectral technology. Moreover, the relationship among SWC, SOM and NSMI were analyzed. The results showed that the accuracy of spectral monitor for SOM among the classifications were significantly different, its accuracy was higher than the soils (5%-25%) which was not classified. It indicated that the soil moisture affected the accuracy for monitoring the SOM with hyperspectral technology and the study proved that the most beneficent soil water content for monitoring the SOM was less 10% and higher 20%. On the other hand, the four models for monitoring the SOM by the hyperspectral were constructed by the classification of NSMI, and its accuracy was higher than the classification of SWC. The models for monitoring the SOM by the classification of NSMI were calibrated with the validation parameters of R², RMSE and RPD, and it showed that the four models were available and reliable to quickly and conveniently monitor the SOM by heperspectral. However, the different classifiable ways for soil samples mentioned in the study were naturally similar as all soil samples were classified again with another way. Namely, there may be another optimal classifiable way or method to overcome and eliminate the SWC effect on the accuracy for monitoring SOM. The study will provide some theoretical technology to monitor the SWC and SOM by remote sensing.

  15. It Matters Whether Reading Comprehension Is Conceptualised as Rate or Accuracy

    ERIC Educational Resources Information Center

    Rønberg, Louise Flensted; Petersen, Dorthe Klint

    2016-01-01

    This study shows that it makes a difference whether accuracy measures or rate measures are used when assessing reading comprehension. When the outcome is reading comprehension accuracy (i.e., the number of correct responses), word reading skills (measured as access to orthographic representations) account for a modest amount of the variance in the…

  16. Speed-Accuracy Response Models: Scoring Rules Based on Response Time and Accuracy

    ERIC Educational Resources Information Center

    Maris, Gunter; van der Maas, Han

    2012-01-01

    Starting from an explicit scoring rule for time limit tasks incorporating both response time and accuracy, and a definite trade-off between speed and accuracy, a response model is derived. Since the scoring rule is interpreted as a sufficient statistic, the model belongs to the exponential family. The various marginal and conditional distributions…

  17. Accuracy of Digital vs. Conventional Implant Impressions

    PubMed Central

    Lee, Sang J.; Betensky, Rebecca A.; Gianneschi, Grace E.; Gallucci, German O.

    2015-01-01

    The accuracy of digital impressions greatly influences the clinical viability in implant restorations. The aim of this study is to compare the accuracy of gypsum models acquired from the conventional implant impression to digitally milled models created from direct digitalization by three-dimensional analysis. Thirty gypsum and 30 digitally milled models impressed directly from a reference model were prepared. The models were scanned by a laboratory scanner and 30 STL datasets from each group were imported to an inspection software. The datasets were aligned to the reference dataset by a repeated best fit algorithm and 10 specified contact locations of interest were measured in mean volumetric deviations. The areas were pooled by cusps, fossae, interproximal contacts, horizontal and vertical axes of implant position and angulation. The pooled areas were statistically analysed by comparing each group to the reference model to investigate the mean volumetric deviations accounting for accuracy and standard deviations for precision. Milled models from digital impressions had comparable accuracy to gypsum models from conventional impressions. However, differences in fossae and vertical displacement of the implant position from the gypsum and digitally milled models compared to the reference model, exhibited statistical significance (p<0.001, p=0.020 respectively). PMID:24720423

  18. Task Speed and Accuracy Decrease When Multitasking

    ERIC Educational Resources Information Center

    Lin, Lin; Cockerham, Deborah; Chang, Zhengsi; Natividad, Gloria

    2016-01-01

    As new technologies increase the opportunities for multitasking, the need to understand human capacities for multitasking continues to grow stronger. Is multitasking helping us to be more efficient? This study investigated the multitasking abilities of 168 participants, ages 6-72, by measuring their task accuracy and completion time when they…

  19. Accuracy Assessment for AG500, Electromagnetic Articulograph

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Mefferd, Antje

    2009-01-01

    Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…

  20. Least squares polynomial fits and their accuracy

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1977-01-01

    Equations are presented which attempt to fit least squares polynomials to tables of date. It is concluded that much data are needed to reduce the measurement error standard deviation by a significant amount, however at certain points great accuracy is attained.