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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. PMID

  2. Storing CO2 underground shows promising results

    NASA Astrophysics Data System (ADS)

    Zweigel, Peter; Gale, John

    Long-term underground storage of CO2 is an important element in concepts to reduce atmospheric CO2 emissions as the use of fossil fuels continues. The first results of a multinational research project evaluating the injection of CO2 into a saline aquifer in the North Sea are validating this method of CO2 reduction, and are serving to further define the research needed to develop the technology for large-scale applicability. Reducing the emission of substances that have potentially harmful effects on global climate— for example, CO2—has become a central issue of environmental policy at least since the 1997 Kyoto conference on climate change.

  3. Breast vibro-acoustography: initial results show promise

    PubMed Central

    2012-01-01

    Introduction Vibro-acoustography (VA) is a recently developed imaging modality that is sensitive to the dynamic characteristics of tissue. It detects low-frequency harmonic vibrations in tissue that are induced by the radiation force of ultrasound. Here, we have investigated applications of VA for in vivo breast imaging. Methods A recently developed combined mammography-VA system for in vivo breast imaging was tested on female volunteers, aged 25 years or older, with suspected breast lesions on their clinical examination. After mammography, a set of VA scans was acquired by the experimental device. In a masked assessment, VA images were evaluated independently by 3 reviewers who identified mass lesions and calcifications. The diagnostic accuracy of this imaging method was determined by comparing the reviewers' responses with clinical data. Results We collected images from 57 participants: 7 were used for training and 48 for evaluation of diagnostic accuracy (images from 2 participants were excluded because of unexpected imaging artifacts). In total, 16 malignant and 32 benign lesions were examined. Specificity for diagnostic accuracy was 94% or higher for all 3 reviewers, but sensitivity varied (69% to 100%). All reviewers were able to detect 97% of masses, but sensitivity for detection of calcification was lower (≤ 72% for all reviewers). Conclusions VA can be used to detect various breast abnormalities, including calcifications and benign and malignant masses, with relatively high specificity. VA technology may lead to a new clinical tool for breast imaging applications. PMID:23021305

  4. 14. DETAIL VIEW OF BUTTRESS 4 SHOWING THE RESULTS OF ...

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

    14. DETAIL VIEW OF BUTTRESS 4 SHOWING THE RESULTS OF INADEQUATE TAMPING. THE SIZE OF THE GRANITE AGGREGATE USED IN THE DAMS CONCRETE IS CLEARLY SHOWN. - Hume Lake Dam, Sequioa National Forest, Hume, Fresno County, CA

  5. 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

  6. Emerging Trends in Contextual Learning Show Positive Results for Students.

    ERIC Educational Resources Information Center

    WorkAmerica, 2001

    2001-01-01

    This issue focuses on contextual learning (CL), in which students master rigorous academic content in real-world or work-based learning experiences. "Emerging Trends in CL Show Positive Results for Students" discusses CL as an important strategy for improving student achievement. It describes: how CL raises the bar for all students, challenging…

  7. 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…

  8. Improved Accuracy of the Gravity Probe B Science Results

    NASA Astrophysics Data System (ADS)

    Conklin, John; Adams, M.; Aljadaan, A.; Aljibreen, H.; Almeshari, M.; Alsuwaidan, B.; Bencze, W.; Buchman, S.; Clarke, B.; Debra, D. B.; Everitt, C. W. F.; Heifetz, M.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart, J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Worden, P. W., Jr.

    This paper presents the progress in the science data analysis for the Gravity Probe B (GP-B) experiment. GP-B, sponsored by NASA and launched in April of 2004, tests two fundamental predictions of general relativity, the geodetic effect and the frame-dragging effect. The GP-B spacecraft measures the non-Newtonian drift rates of four ultra-precise cryogenic gyroscopes placed in a circular polar Low Earth Orbit. Science data was collected from 28 August 2004 until cryogen depletion on 29 September 2005. The data analysis is complicated by two unexpected phenomena, a) a continually damping gyroscope polhode affecting the calibration of the gyro readout scale factor, and b) two larger than expected classes of Newtonian torque acting on the gyroscopes. Experimental evidence strongly suggests that both effects are caused by non-uniform electric potentials (i.e. the patch effect) on the surfaces of the gyroscope rotor and its housing. At the end of 2008, the data analysis team reported intermediate results showing that the two complications are well understood and are separable from the relativity signal. Since then we have developed the final GP-B data analysis code, the "2-second Filter", which provides the most accurate and precise determination of the non-Newtonian drifts attainable in the presence of the two Newtonian torques and the fundamental instrument noise. This limit is roughly 5

  9. Climatic associations of British species distributions show good transferability in time but low predictive accuracy for range change.

    PubMed

    Rapacciuolo, Giovanni; Roy, David B; Gillings, Simon; Fox, Richard; Walker, Kevin; Purvis, Andy

    2012-01-01

    Conservation planners often wish to predict how species distributions will change in response to environmental changes. Species distribution models (SDMs) are the primary tool for making such predictions. Many methods are widely used; however, they all make simplifying assumptions, and predictions can therefore be subject to high uncertainty. With global change well underway, field records of observed range shifts are increasingly being used for testing SDM transferability. We used an unprecedented distribution dataset documenting recent range changes of British vascular plants, birds, and butterflies to test whether correlative SDMs based on climate change provide useful approximations of potential distribution shifts. We modelled past species distributions from climate using nine single techniques and a consensus approach, and projected the geographical extent of these models to a more recent time period based on climate change; we then compared model predictions with recent observed distributions in order to estimate the temporal transferability and prediction accuracy of our models. We also evaluated the relative effect of methodological and taxonomic variation on the performance of SDMs. Models showed good transferability in time when assessed using widespread metrics of accuracy. However, models had low accuracy to predict where occupancy status changed between time periods, especially for declining species. Model performance varied greatly among species within major taxa, but there was also considerable variation among modelling frameworks. Past climatic associations of British species distributions retain a high explanatory power when transferred to recent time--due to their accuracy to predict large areas retained by species--but fail to capture relevant predictors of change. We strongly emphasize the need for caution when using SDMs to predict shifts in species distributions: high explanatory power on temporally-independent records--as assessed using

  10. From genus to phylum: large-subunit and internal transcribed spacer rRNA operon regions show similar classification accuracies influenced by database composition.

    PubMed

    Porras-Alfaro, Andrea; Liu, Kuan-Liang; Kuske, Cheryl R; Xie, Gary

    2014-02-01

    We compared the classification accuracy of two sections of the fungal internal transcribed spacer (ITS) region, individually and combined, and the 5' section (about 600 bp) of the large-subunit rRNA (LSU), using a naive Bayesian classifier and BLASTN. A hand-curated ITS-LSU training set of 1,091 sequences and a larger training set of 8,967 ITS region sequences were used. Of the factors evaluated, database composition and quality had the largest effect on classification accuracy, followed by fragment size and use of a bootstrap cutoff to improve classification confidence. The naive Bayesian classifier and BLASTN gave similar results at higher taxonomic levels, but the classifier was faster and more accurate at the genus level when a bootstrap cutoff was used. All of the ITS and LSU sections performed well (>97.7% accuracy) at higher taxonomic ranks from kingdom to family, and differences between them were small at the genus level (within 0.66 to 1.23%). When full-length sequence sections were used, the LSU outperformed the ITS1 and ITS2 fragments at the genus level, but the ITS1 and ITS2 showed higher accuracy when smaller fragment sizes of the same length and a 50% bootstrap cutoff were used. In a comparison using the larger ITS training set, ITS1 and ITS2 had very similar accuracy classification for fragments between 100 and 200 bp. Collectively, the results show that any of the ITS or LSU sections we tested provided comparable classification accuracy to the genus level and underscore the need for larger and more diverse classification training sets.

  11. 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.

  12. 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.

  13. Probing the limits of accuracy in electronic structure calculations: is theory capable of results uniformly better than "chemical accuracy"?

    PubMed

    Feller, David; Peterson, Kirk A

    2007-03-21

    Current limitations in electronic structure methods are discussed from the perspective of their potential to contribute to inherent uncertainties in predictions of molecular properties, with an emphasis on atomization energies (or heats of formation). The practical difficulties arising from attempts to achieve high accuracy are illustrated via two case studies: the carbon dimer (C2) and the hydroperoxyl radical (HO2). While the HO2 wave function is dominated by a single configuration, the carbon dimer involves considerable multiconfigurational character. In addition to these two molecules, statistical results will be presented for a much larger sample of molecules drawn from the Computational Results Database. The goal of this analysis will be to determine if a combination of coupled cluster theory with large 1-particle basis sets and careful incorporation of several computationally expensive smaller corrections can yield uniform agreement with experiment to better than "chemical accuracy" (+/-1 kcal/mol). In the case of HO2, the best current theoretical estimate of the zero-point-inclusive, spin-orbit corrected atomization energy (SigmaD0=166.0+/-0.3 kcal/mol) and the most recent Active Thermochemical Table (ATcT) value (165.97+/-0.06 kcal/mol) are in excellent agreement. For C2 the agreement is only slightly poorer, with theory (D0=143.7+/-0.3 kcal/mol) almost encompassing the most recent ATcT value (144.03+/-0.13 kcal/mol). For a larger collection of 68 molecules, a mean absolute deviation of 0.3 kcal/mol was found. The same high level of theory that produces good agreement for atomization energies also appears capable of predicting bond lengths to an accuracy of +/-0.001 A. PMID:17381194

  14. Probing the limits of accuracy in electronic structure calculations: Is theory capable of results uniformly better than ``chemical accuracy''?

    NASA Astrophysics Data System (ADS)

    Feller, David; Peterson, Kirk A.

    2007-03-01

    Current limitations in electronic structure methods are discussed from the perspective of their potential to contribute to inherent uncertainties in predictions of molecular properties, with an emphasis on atomization energies (or heats of formation). The practical difficulties arising from attempts to achieve high accuracy are illustrated via two case studies: the carbon dimer (C2) and the hydroperoxyl radical (HO2). While the HO2 wave function is dominated by a single configuration, the carbon dimer involves considerable multiconfigurational character. In addition to these two molecules, statistical results will be presented for a much larger sample of molecules drawn from the Computational Results Database. The goal of this analysis will be to determine if a combination of coupled cluster theory with large 1-particle basis sets and careful incorporation of several computationally expensive smaller corrections can yield uniform agreement with experiment to better than "chemical accuracy" (±1kcal /mol). In the case of HO2, the best current theoretical estimate of the zero-point-inclusive, spin-orbit corrected atomization energy (ΣD0=166.0±0.3kcal /mol) and the most recent Active Thermochemical Table (ATcT) value (165.97±0.06kcal/mol) are in excellent agreement. For C2 the agreement is only slightly poorer, with theory (D0=143.7±0.3kcal/mol) almost encompassing the most recent ATcT value (144.03±0.13kcal/mol). For a larger collection of 68molecules, a mean absolute deviation of 0.3kcal/mol was found. The same high level of theory that produces good agreement for atomization energies also appears capable of predicting bond lengths to an accuracy of ±0.001Å.

  15. 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.

  16. Accuracy of Student Recall of Strong Interest Inventory Results 1 Year after Interpretation.

    ERIC Educational Resources Information Center

    Hansen, Jo-Ida C.; And Others

    1994-01-01

    Examined how accurately college students (n=87) recalled information from their Strong Interest Inventory (SII) profiles one year later. Significant number of participants recalled at least one profile result, but accuracy of recall varied by type of scale and percentage of participants who first remembered something and then remembered it…

  17. Evaluating the Accuracy of Results for Teacher Implemented Trial-Based Functional Analyses.

    PubMed

    Rispoli, Mandy; Ninci, Jennifer; Burke, Mack D; Zaini, Samar; Hatton, Heather; Sanchez, Lisa

    2015-09-01

    Trial-based functional analysis (TBFA) allows for the systematic and experimental assessment of challenging behavior in applied settings. The purposes of this study were to evaluate a professional development package focused on training three Head Start teachers to conduct TBFAs with fidelity during ongoing classroom routines. To assess the accuracy of the TBFA results, the effects of a function-based intervention derived from the TBFA were compared with the effects of a non-function-based intervention. Data were collected on child challenging behavior and appropriate communication. An A-B-A-C-D design was utilized in which A represented baseline, and B and C consisted of either function-based or non-function-based interventions counterbalanced across participants, and D represented teacher implementation of the most effective intervention. Results showed that the function-based intervention produced greater decreases in challenging behavior and greater increases in appropriate communication than the non-function-based intervention for all three children.

  18. Evaluating the Accuracy of Results for Teacher Implemented Trial-Based Functional Analyses.

    PubMed

    Rispoli, Mandy; Ninci, Jennifer; Burke, Mack D; Zaini, Samar; Hatton, Heather; Sanchez, Lisa

    2015-09-01

    Trial-based functional analysis (TBFA) allows for the systematic and experimental assessment of challenging behavior in applied settings. The purposes of this study were to evaluate a professional development package focused on training three Head Start teachers to conduct TBFAs with fidelity during ongoing classroom routines. To assess the accuracy of the TBFA results, the effects of a function-based intervention derived from the TBFA were compared with the effects of a non-function-based intervention. Data were collected on child challenging behavior and appropriate communication. An A-B-A-C-D design was utilized in which A represented baseline, and B and C consisted of either function-based or non-function-based interventions counterbalanced across participants, and D represented teacher implementation of the most effective intervention. Results showed that the function-based intervention produced greater decreases in challenging behavior and greater increases in appropriate communication than the non-function-based intervention for all three children. PMID:26069219

  19. 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.

  20. Flight Test Results: CTAS Cruise/Descent Trajectory Prediction Accuracy for En route ATC Advisories

    NASA Technical Reports Server (NTRS)

    Green, S.; Grace, M.; Williams, D.

    1999-01-01

    The Center/TRACON Automation System (CTAS), under development at NASA Ames Research Center, is designed to assist controllers with the management and control of air traffic transitioning to/from congested airspace. This paper focuses on the transition from the en route environment, to high-density terminal airspace, under a time-based arrival-metering constraint. Two flight tests were conducted at the Denver Air Route Traffic Control Center (ARTCC) to study trajectory-prediction accuracy, the key to accurate Decision Support Tool advisories such as conflict detection/resolution and fuel-efficient metering conformance. In collaboration with NASA Langley Research Center, these test were part of an overall effort to research systems and procedures for the integration of CTAS and flight management systems (FMS). The Langley Transport Systems Research Vehicle Boeing 737 airplane flew a combined total of 58 cruise-arrival trajectory runs while following CTAS clearance advisories. Actual trajectories of the airplane were compared to CTAS and FMS predictions to measure trajectory-prediction accuracy and identify the primary sources of error for both. The research airplane was used to evaluate several levels of cockpit automation ranging from conventional avionics to a performance-based vertical navigation (VNAV) FMS. Trajectory prediction accuracy was analyzed with respect to both ARTCC radar tracking and GPS-based aircraft measurements. This paper presents detailed results describing the trajectory accuracy and error sources. Although differences were found in both accuracy and error sources, CTAS accuracy was comparable to the FMS in terms of both meter-fix arrival-time performance (in support of metering) and 4D-trajectory prediction (key to conflict prediction). Overall arrival time errors (mean plus standard deviation) were measured to be approximately 24 seconds during the first flight test (23 runs) and 15 seconds during the second flight test (25 runs). The major

  1. 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.

  2. 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.

  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

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2007-01-01

    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…

  5. 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.

  6. Diagnostic Accuracy of Procalcitonin for Predicting Blood Culture Results in Patients With Suspected Bloodstream Infection

    PubMed Central

    Oussalah, Abderrahim; Ferrand, Janina; Filhine-Tresarrieu, Pierre; Aissa, Nejla; Aimone-Gastin, Isabelle; Namour, Fares; Garcia, Matthieu; Lozniewski, Alain; Guéant, Jean-Louis

    2015-01-01

    Abstract Previous studies have suggested that procalcitonin is a reliable marker for predicting bacteremia. However, these studies have had relatively small sample sizes or focused on a single clinical entity. The primary endpoint of this study was to investigate the diagnostic accuracy of procalcitonin for predicting or excluding clinically relevant pathogen categories in patients with suspected bloodstream infections. The secondary endpoint was to look for organisms significantly associated with internationally validated procalcitonin intervals. We performed a cross-sectional study that included 35,343 consecutive patients who underwent concomitant procalcitonin assays and blood cultures for suspected bloodstream infections. Biochemical and microbiological data were systematically collected in an electronic database and extracted for purposes of this study. Depending on blood culture results, patients were classified into 1 of the 5 following groups: negative blood culture, Gram-positive bacteremia, Gram-negative bacteremia, fungi, and potential contaminants found in blood cultures (PCBCs). The highest procalcitonin concentration was observed in patients with blood cultures growing Gram-negative bacteria (median 2.2 ng/mL [IQR 0.6–12.2]), and the lowest procalcitonin concentration was observed in patients with negative blood cultures (median 0.3 ng/mL [IQR 0.1–1.1]). With optimal thresholds ranging from ≤0.4 to ≤0.75 ng/mL, procalcitonin had a high diagnostic accuracy for excluding all pathogen categories with the following negative predictive values: Gram-negative bacteria (98.9%) (including enterobacteria [99.2%], nonfermenting Gram-negative bacilli [99.7%], and anaerobic bacteria [99.9%]), Gram-positive bacteria (98.4%), and fungi (99.6%). A procalcitonin concentration ≥10 ng/mL was associated with a high risk of Gram-negative (odds ratio 5.98; 95% CI, 5.20–6.88) or Gram-positive (odds ratio 3.64; 95% CI, 3.11–4.26) bacteremia but

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:27352918

  11. Increased movement accuracy and reduced EMG activity as the result of adopting an external focus of attention.

    PubMed

    Zachry, Tiffany; Wulf, Gabriele; Mercer, John; Bezodis, Neil

    2005-10-30

    The performance and learning of motor skills has been shown to be enhanced if the performer adopts an external focus of attention (focus on the movement effect) compared to an internal focus (focus on the movements themselves) [G. Wulf, W. Prinz, Directing attention to movement effects enhances learning: a review, Psychon. Bull. Rev. 8 (2001) 648-660]. While most previous studies examining attentional focus effects have exclusively used performance outcome (e.g., accuracy) measures, in the present study electromyography (EMG) was used to determine neuromuscular correlates of external versus internal focus differences in movement outcome. Participants performed basketball free throws under both internal focus (wrist motion) and external focus (basket) conditions. EMG activity was recorded for m. flexor carpi radialis, m. biceps brachii, m. triceps triceps brachii, and m. deltoid of each participant's shooting arm. The results showed that free throw accuracy was greater when participants adopted an external compared to an internal focus. In addition, EMG activity of the biceps and triceps muscles was lower with an external relative to an internal focus. This suggests that an external focus of attention enhances movement economy, and presumably reduces "noise" in the motor system that hampers fine movement control and makes the outcome of the movement less reliable.

  12. Accuracy and repeatability of weighing for occupational hygiene measurements: results from an inter-laboratory comparison.

    PubMed

    Stacey, Peter; Revell, Graham; Tylee, Barry

    2002-11-01

    Gravimetric analysis is a fundamental technique frequently used in occupational hygiene assessments, but few studies have investigated its repeatability and reproducibility. Four inter-laboratory comparisons are discussed in this paper. The first involved 32 laboratories weighing 25 mm diameter glassfibre filters, the second involved 11 laboratories weighing 25 mm diameter PVC filters and the third involved eight laboratories weighing plastic IOM heads with 25 mm diameter glassfibre filters. Data from the third study found that measurements using this type of IOM head were unreliable. A fourth study, to ascertain if laboratories could improve their performance, involved a selected sub-group of 10 laboratories from the first exercise that analysed the 25 mm diameter glassfibre filters. The studies tested the analytical measurement process and not just the variation in weighings obtained on blank filters, as previous studies have done. Graphs of data from the first and second exercises suggest that a power curve relationship exists between reproducibility and loading and repeatability and loading. The relationship for reproducibility in the first study followed the equation log s(R) = -0.62 log m + 0.86 and in the second study log s(R) = -0.64 log m + 0.57, where s(R) is the reproducibility in terms of per cent relative standard deviation (%RSD) and m is the weight of loading in milligrams. The equation for glassfibre filters from the first exercise suggested that at a measurement of 0.4 mg (about a tenth of the United Kingdom legislative definition of a hazardous substance for a respirable dust for an 8 h sample), the measurement reproducibility is more than +/-25% (2sigma). The results from PVC filters had better repeatability estimates than the glassfibre filters, but overall they had similar estimates of reproducibility. An improvement in both the reproducibility and repeatability for glassfibre filters was observed in the fourth study. This improvement reduced

  13. Accuracy and repeatability of weighing for occupational hygiene measurements: results from an inter-laboratory comparison.

    PubMed

    Stacey, Peter; Revell, Graham; Tylee, Barry

    2002-11-01

    Gravimetric analysis is a fundamental technique frequently used in occupational hygiene assessments, but few studies have investigated its repeatability and reproducibility. Four inter-laboratory comparisons are discussed in this paper. The first involved 32 laboratories weighing 25 mm diameter glassfibre filters, the second involved 11 laboratories weighing 25 mm diameter PVC filters and the third involved eight laboratories weighing plastic IOM heads with 25 mm diameter glassfibre filters. Data from the third study found that measurements using this type of IOM head were unreliable. A fourth study, to ascertain if laboratories could improve their performance, involved a selected sub-group of 10 laboratories from the first exercise that analysed the 25 mm diameter glassfibre filters. The studies tested the analytical measurement process and not just the variation in weighings obtained on blank filters, as previous studies have done. Graphs of data from the first and second exercises suggest that a power curve relationship exists between reproducibility and loading and repeatability and loading. The relationship for reproducibility in the first study followed the equation log s(R) = -0.62 log m + 0.86 and in the second study log s(R) = -0.64 log m + 0.57, where s(R) is the reproducibility in terms of per cent relative standard deviation (%RSD) and m is the weight of loading in milligrams. The equation for glassfibre filters from the first exercise suggested that at a measurement of 0.4 mg (about a tenth of the United Kingdom legislative definition of a hazardous substance for a respirable dust for an 8 h sample), the measurement reproducibility is more than +/-25% (2sigma). The results from PVC filters had better repeatability estimates than the glassfibre filters, but overall they had similar estimates of reproducibility. An improvement in both the reproducibility and repeatability for glassfibre filters was observed in the fourth study. This improvement reduced

  14. Analysis of Factors Influencing Measurement Accuracy of Al Alloy Tensile Test Results

    NASA Astrophysics Data System (ADS)

    Podgornik, Bojan; Žužek, Borut; Sedlaček, Marko; Kevorkijan, Varužan; Hostej, Boris

    2016-02-01

    In order to properly use materials in design, a complete understanding of and information on their mechanical properties, such as yield and ultimate tensile strength must be obtained. Furthermore, as the design of automotive parts is constantly pushed toward higher limits, excessive measuring uncertainty can lead to unexpected premature failure of the component, thus requiring reliable determination of material properties with low uncertainty. The aim of the present work was to evaluate the effect of different metrology factors, including the number of tested samples, specimens machining and surface quality, specimens input diameter, type of testing and human error on the tensile test results and measurement uncertainty when performed on 2xxx series Al alloy. Results show that the most significant contribution to measurement uncertainty comes from the number of samples tested, which can even exceed 1 %. Furthermore, moving from experimental laboratory conditions to very intense industrial environment further amplifies measurement uncertainty, where even if using automated systems human error cannot be neglected.

  15. 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

  16. Comparison of some results of program SHOW with other solar hot water computer programs

    NASA Astrophysics Data System (ADS)

    Young, M. F.; Baughn, J. W.

    Subroutines and the driver program for the simulation code SHOW (solar hot water) for solar thermosyphon systems are discussed, and simulations are compared with predictions by the F-CHART and TRNSYS codes. SHOW has the driver program MAIN, which defines the system control logic for choosing the appropriate system subroutine for analysis. Ten subroutines are described, which account for the solar system physical parameters, the weather data, the manufacturer-supplied system specifications, mass flow rates, pumped systems, total transformed radiation, load use profiles, stratification in storage, an electric water heater, and economic analyses. The three programs are employed to analyze a thermosiphon installation in Sacramento with two storage tanks. TRNSYS and SHOW were in agreement and lower than F-CHARt for annual predictions, although significantly more computer time was necessary to make TRNSYS converge.

  17. Data for behavioral results and brain regions showing a time effect during pair-association retrieval.

    PubMed

    Jimura, Koji; Hirose, Satoshi; Wada, Hiroyuki; Yoshizawa, Yasunori; Imai, Yoshio; Akahane, Masaaki; Machida, Toru; Shirouzu, Ichiro; Koike, Yasuharu; Konishi, Seiki

    2016-09-01

    The current data article provides behavioral and neuroimaging data for the research article "Relatedness-dependent rapid development of brain activity in anterior temporal cortex during pair-association retrieval" (Jimura et al., 2016) [1]. Behavioral performance is provided in a table. Fig. 2 of the article is based on this table. Brain regions showing time effect are provided in a table. A statistical activation map for the time effect is shown in Fig. 3C of the article. PMID:27508239

  18. Relative Accuracy Evaluation

    PubMed Central

    Zhang, Yan; Wang, Hongzhi; Yang, Zhongsheng; Li, Jianzhong

    2014-01-01

    The quality of data plays an important role in business analysis and decision making, and data accuracy is an important aspect in data quality. Thus one necessary task for data quality management is to evaluate the accuracy of the data. And in order to solve the problem that the accuracy of the whole data set is low while a useful part may be high, it is also necessary to evaluate the accuracy of the query results, called relative accuracy. However, as far as we know, neither measure nor effective methods for the accuracy evaluation methods are proposed. Motivated by this, for relative accuracy evaluation, we propose a systematic method. We design a relative accuracy evaluation framework for relational databases based on a new metric to measure the accuracy using statistics. We apply the methods to evaluate the precision and recall of basic queries, which show the result's relative accuracy. We also propose the method to handle data update and to improve accuracy evaluation using functional dependencies. Extensive experimental results show the effectiveness and efficiency of our proposed framework and algorithms. PMID:25133752

  19. 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.

  20. Improving the Accuracy of Whole Genome Prediction for Complex Traits Using the Results of Genome Wide Association Studies

    PubMed Central

    Zhang, Zhe; Ober, Ulrike; Erbe, Malena; Zhang, Hao; Gao, Ning; He, Jinlong; Li, Jiaqi; Simianer, Henner

    2014-01-01

    Utilizing the whole genomic variation of complex traits to predict the yet-to-be observed phenotypes or unobserved genetic values via whole genome prediction (WGP) and to infer the underlying genetic architecture via genome wide association study (GWAS) is an interesting and fast developing area in the context of human disease studies as well as in animal and plant breeding. Though thousands of significant loci for several species were detected via GWAS in the past decade, they were not used directly to improve WGP due to lack of proper models. Here, we propose a generalized way of building trait-specific genomic relationship matrices which can exploit GWAS results in WGP via a best linear unbiased prediction (BLUP) model for which we suggest the name BLUP|GA. Results from two illustrative examples show that using already existing GWAS results from public databases in BLUP|GA improved the accuracy of WGP for two out of the three model traits in a dairy cattle data set, and for nine out of the 11 traits in a rice diversity data set, compared to the reference methods GBLUP and BayesB. While BLUP|GA outperforms BayesB, its required computing time is comparable to GBLUP. Further simulation results suggest that accounting for publicly available GWAS results is potentially more useful for WGP utilizing smaller data sets and/or traits of low heritability, depending on the genetic architecture of the trait under consideration. To our knowledge, this is the first study incorporating public GWAS results formally into the standard GBLUP model and we think that the BLUP|GA approach deserves further investigations in animal breeding, plant breeding as well as human genetics. PMID:24663104

  1. Improving the accuracy of whole genome prediction for complex traits using the results of genome wide association studies.

    PubMed

    Zhang, Zhe; Ober, Ulrike; Erbe, Malena; Zhang, Hao; Gao, Ning; He, Jinlong; Li, Jiaqi; Simianer, Henner

    2014-01-01

    Utilizing the whole genomic variation of complex traits to predict the yet-to-be observed phenotypes or unobserved genetic values via whole genome prediction (WGP) and to infer the underlying genetic architecture via genome wide association study (GWAS) is an interesting and fast developing area in the context of human disease studies as well as in animal and plant breeding. Though thousands of significant loci for several species were detected via GWAS in the past decade, they were not used directly to improve WGP due to lack of proper models. Here, we propose a generalized way of building trait-specific genomic relationship matrices which can exploit GWAS results in WGP via a best linear unbiased prediction (BLUP) model for which we suggest the name BLUP|GA. Results from two illustrative examples show that using already existing GWAS results from public databases in BLUP|GA improved the accuracy of WGP for two out of the three model traits in a dairy cattle data set, and for nine out of the 11 traits in a rice diversity data set, compared to the reference methods GBLUP and BayesB. While BLUP|GA outperforms BayesB, its required computing time is comparable to GBLUP. Further simulation results suggest that accounting for publicly available GWAS results is potentially more useful for WGP utilizing smaller data sets and/or traits of low heritability, depending on the genetic architecture of the trait under consideration. To our knowledge, this is the first study incorporating public GWAS results formally into the standard GBLUP model and we think that the BLUP|GA approach deserves further investigations in animal breeding, plant breeding as well as human genetics.

  2. 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.

  3. 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.

  4. Accuracy of liquid based versus conventional cytology: overall results of new technologies for cervical cancer screening: randomised controlled trial

    PubMed Central

    Cuzick, Jack; Pierotti, Paola; Cariaggi, Maria Paola; Palma, Paolo Dalla; Naldoni, Carlo; Ghiringhello, Bruno; Giorgi-Rossi, Paolo; Minucci, Daria; Parisio, Franca; Pojer, Ada; Schiboni, Maria Luisa; Sintoni, Catia; Zorzi, Manuel; Segnan, Nereo; Confortini, Massimo

    2007-01-01

    Objective To compare the accuracy of conventional cytology with liquid based cytology for primary screening of cervical cancer. Design Randomised controlled trial. Setting Nine screening programmes in Italy. Participants Women aged 25-60 attending for a new screening round: 22 466 were assigned to the conventional arm and 22 708 were assigned to the experimental arm. Interventions Conventional cytology compared with liquid based cytology and testing for human papillomavirus. Main outcome measure Relative sensitivity for cervical intraepithelial neoplasia of grade 2 or more at blindly reviewed histology, with atypical cells of undetermined significance or more severe cytology considered a positive result. Results In an intention to screen analysis liquid based cytology showed no significant increase in sensitivity for cervical intraepithelial neoplasia of grade 2 or more (relative sensitivity 1.17, 95% confidence interval 0.87 to 1.56) whereas the positive predictive value was reduced (relative positive predictive value v conventional cytology 0.58, 0.44 to 0.77). Liquid based cytology detected more lesions of grade 1 or more (relative sensitivity 1.68, 1.40 to 2.02), with a larger increase among women aged 25-34 (P for heterogeneity 0.0006), but did not detect more lesions of grade 3 or more (relative sensitivity 0.84, 0.56 to 1.25). Results were similar when only low grade intraepithelial lesions or more severe cytology were considered a positive result. No evidence was found of heterogeneity between centres or of improvement with increasing time from start of the study. The relative frequency of women with at least one unsatisfactory result was lower with liquid based cytology (0.62, 0.56 to 0.69). Conclusion Liquid based cytology showed no statistically significant difference in sensitivity to conventional cytology for detection of cervical intraepithelial neoplasia of grade 2 or more. More positive results were found, however, leading to a lower positive

  5. Accuracy of navigation-assisted acetabular component positioning studied by computed tomography measurements: methods and results.

    PubMed

    Ybinger, Thomas; Kumpan, W; Hoffart, H E; Muschalik, B; Bullmann, W; Zweymüller, K

    2007-09-01

    The postoperative position of the acetabular component is key for the outcome of total hip arthroplasty. Various aids have been developed to support the surgeon during implant placement. In a prospective study involving 4 centers, the computer-recorded cup alignment of 37 hip systems at the end of navigation-assisted surgery was compared with the cup angles measured on postoperative computerized tomograms. This comparison showed an average difference of 3.5 degrees (SD, 4.4 degrees ) for inclination and 6.5 degrees (SD, 7.3 degrees ) for anteversion angles. The differences in inclination correlated with the thickness of the soft tissue overlying the anterior superior iliac spine (r = 0.44; P = .007), whereas the differences in anteversion showed a correlation with the thickness of the soft tissue overlying the pubic tubercles (r = 0.52; P = .001). In centers experienced in the use of navigational tools, deviations were smaller than in units with little experience in their use. PMID:17826270

  6. Gravity Probe B data analysis status and potential for improved accuracy of scientific results

    NASA Astrophysics Data System (ADS)

    Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke, B.; Conklin, J.; DeBra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lockhart, J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Turneaure, J. P.; Worden, P. W., Jr.

    2008-06-01

    Gravity Probe B (GP-B) is a landmark physics experiment in space designed to yield precise tests of two fundamental predictions of Einstein's theory of general relativity, the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Launched on 20 April 2004, data collection began on 28 August 2004 and science operations were completed on 29 September 2005 upon liquid helium depletion. During the course of the experiment, two unexpected and mutually-reinforcing complications were discovered: (1) larger than expected 'misalignment' torques on the gyroscopes producing classical drifts larger than the relativity effects under study and (2) a damped polhode oscillation that complicated the calibration of the instrument's scale factor against the aberration of starlight. Steady progress through 2006 and 2007 established the methods for treating both problems; in particular, an extended effort from January 2007 on 'trapped flux mapping' led in August 2007 to a dramatic breakthrough, resulting in a factor of ~20 reduction in data scatter. This paper reports results up to November 2007. Detailed investigation of a central 85-day segment of the data has yielded robust measurements of both relativity effects. Expansion to the complete science data set, along with anticipated improvements in modeling and in the treatment of systematic errors may be expected to yield a 3 6% determination of the frame-dragging effect.

  7. Analysis of the Accuracy of Weight Loss Information Search Engine Results on the Internet

    PubMed Central

    Shokar, Navkiran K.; Peñaranda, Eribeth; Nguyen, Norma

    2014-01-01

    Objectives. We systematically identified and evaluated the quality and comprehensiveness of online information related to weight loss that users were likely to access. Methods. We evaluated the content quality, accessibility of the information, and author credentials for Web sites in 2012 that were identified from weight loss specific queries that we generated. We scored the content with respect to available evidence-based guidelines for weight loss. Results. One hundred three Web sites met our eligibility criteria (21 commercial, 52 news/media, 7 blogs, 14 medical, government, or university, and 9 unclassified sites). The mean content quality score was 3.75 (range = 0–16; SD = 2.48). Approximately 5% (4.85%) of the sites scored greater than 8 (of 12) on nutrition, physical activity, and behavior. Content quality score varied significantly by type of Web site; the medical, government, or university sites (mean = 4.82, SD = 2.27) and blogs (mean = 6.33, SD = 1.99) had the highest scores. Commercial (mean = 2.37, SD = 2.60) or news/media sites (mean = 3.52, SD = 2.31) had the lowest scores (analysis of variance P < .005). Conclusions. The weight loss information that people were likely to access online was often of substandard quality because most comprehensive and quality Web sites ranked too low in search results. PMID:25122030

  8. Gravity Probe B Data Analysis. Status and Potential for Improved Accuracy of Scientific Results

    NASA Astrophysics Data System (ADS)

    Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke, B.; Conklin, J. W.; Debra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart, J. M.; Mester, J. C.; Muhlfelder, B.; Ohshima, Y.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Wang, S.; Worden, P. W.

    2009-12-01

    This is the first of five connected papers detailing progress on the Gravity Probe B (GP-B) Relativity Mission. GP-B, launched 20 April 2004, is a landmark physics experiment in space to test two fundamental predictions of Einstein’s general relativity theory, the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection began 28 August 2004 and science operations were completed 29 September 2005. The data analysis has proven deeper than expected as a result of two mutually reinforcing complications in gyroscope performance: (1) a changing polhode path affecting the calibration of the gyroscope scale factor C g against the aberration of starlight and (2) two larger than expected manifestations of a Newtonian gyro torque due to patch potentials on the rotor and housing. In earlier papers, we reported two methods, ‘geometric’ and ‘algebraic’, for identifying and removing the first Newtonian effect (‘misalignment torque’), and also a preliminary method of treating the second (‘roll-polhode resonance torque’). Central to the progress in both torque modeling and C g determination has been an extended effort on “Trapped Flux Mapping” commenced in November 2006. A turning point came in August 2008 when it became possible to include a detailed history of the resonance torques into the computation. The East-West (frame-dragging) effect is now plainly visible in the processed data. The current statistical uncertainty from an analysis of 155 days of data is 5.4 marc-s/yr (˜14% of the predicted effect), though it must be emphasized that this is a preliminary result requiring rigorous investigation of systematics by methods discussed in the accompanying paper by Muhlfelder et al. A covariance analysis incorporating models of the patch effect torques indicates that a 3-5% determination of frame-dragging is possible with more complete, computationally intensive data analysis.

  9. 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

  10. Contribution of Sample Processing to Variability and Accuracy of the Results of Pesticide Residue Analysis in Plant Commodities.

    PubMed

    Ambrus, Árpád; Buczkó, Judit; Hamow, Kamirán Á; Juhász, Viktor; Solymosné Majzik, Etelka; Szemánné Dobrik, Henriett; Szitás, Róbert

    2016-08-10

    Significant reduction of concentration of some pesticide residues and substantial increase of the uncertainty of the results derived from the homogenization of sample materials have been reported in scientific papers long ago. Nevertheless, performance of methods is frequently evaluated on the basis of only recovery tests, which exclude sample processing. We studied the effect of sample processing on accuracy and uncertainty of the measured residue values with lettuce, tomato, and maize grain samples applying mixtures of selected pesticides. The results indicate that the method is simple and robust and applicable in any pesticide residue laboratory. The analytes remaining in the final extract are influenced by their physical-chemical properties, the nature of the sample material, the temperature of comminution of sample, and the mass of test portion extracted. Consequently, validation protocols should include testing the effect of sample processing, and the performance of the complete method should be regularly checked within internal quality control. PMID:26755282

  11. Research on the classification result and accuracy of building windows in high resolution satellite images: take the typical rural buildings in Guangxi, China, as an example

    NASA Astrophysics Data System (ADS)

    Li, Baishou; Gao, Yujiu

    2015-12-01

    The information extracted from the high spatial resolution remote sensing images has become one of the important data sources of the GIS large scale spatial database updating. The realization of the building information monitoring using the high resolution remote sensing, building small scale information extracting and its quality analyzing has become an important precondition for the applying of the high-resolution satellite image information, because of the large amount of regional high spatial resolution satellite image data. In this paper, a clustering segmentation classification evaluation method for the high resolution satellite images of the typical rural buildings is proposed based on the traditional KMeans clustering algorithm. The factors of separability and building density were used for describing image classification characteristics of clustering window. The sensitivity of the factors influenced the clustering result was studied from the perspective of the separability between high image itself target and background spectrum. This study showed that the number of the sample contents is the important influencing factor to the clustering accuracy and performance, the pixel ratio of the objects in images and the separation factor can be used to determine the specific impact of cluster-window subsets on the clustering accuracy, and the count of window target pixels (Nw) does not alone affect clustering accuracy. The result can provide effective research reference for the quality assessment of the segmentation and classification of high spatial resolution remote sensing images.

  12. 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

  13. 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).

  14. 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.

  15. 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.

  16. International test results for objective lens quality, resolution, spectral accuracy and spectral separation for confocal laser scanning microscopes.

    PubMed

    Cole, Richard W; Thibault, Marc; Bayles, Carol J; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Opansky, Cynthia; Schulz, Katherine; Brown, Claire M

    2013-12-01

    As part of an ongoing effort to increase image reproducibility and fidelity in addition to improving cross-instrument consistency, we have proposed using four separate instrument quality tests to augment the ones we have previously reported. These four tests assessed the following areas: (1) objective lens quality, (2) resolution, (3) accuracy of the wavelength information from spectral detectors, and (4) the accuracy and quality of spectral separation algorithms. Data were received from 55 laboratories located in 18 countries. The largest source of errors across all tests was user error which could be subdivided between failure to follow provided protocols and improper use of the microscope. This truly emphasizes the importance of proper rigorous training and diligence in performing confocal microscopy experiments and equipment evaluations. It should be noted that there was no discernible difference in quality between confocal microscope manufactures. These tests, as well as others previously reported, will help assess the quality of confocal microscopy equipment and will provide a means to track equipment performance over time. From 62 to 97% of the data sets sent in passed the various tests demonstrating the usefulness and appropriateness of these tests as part of a larger performance testing regiment.

  17. 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

  18. 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.

  19. Presentation Showing Results of a Hydrogeochemical Investigation of the Standard Mine Vicinity, Upper Elk Creek Basin, Colorado

    USGS Publications Warehouse

    Manning, Andrew H.; Verplanck, Philip L.; Mast, M. Alisa; Wanty, Richard B.

    2008-01-01

    PREFACE This Open-File Report consists of a presentation given in Crested Butte, Colorado on December 13, 2007 to the Standard Mine Advisory Group. The presentation was paired with another presentation given by the Colorado Division of Reclamation, Mining, and Safety on the physical features and geology of the Standard Mine. The presentation in this Open-File Report summarizes the results and conclusions of a hydrogeochemical investigation of the Standard Mine performed by the U.S. Geological Survey (Manning and others, in press). The purpose of the investigation was to aid the U.S. Environmental Protection Agency in evaluating remediation options for the Standard Mine site. Additional details and supporting data related to the information in this presentation can be found in Manning and others (in press).

  20. Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation.

    PubMed

    Zhan, Yihong; Cao, Zhenning; Bao, Ning; Li, Jianbo; Wang, Jun; Geng, Tao; Lin, Hao; Lu, Chang

    2012-06-28

    Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency. In this report, we utilized a flow-through electroporation technique that employed continuous 10Hz-10kHz ac field (based on either sine waves or square waves) for electroporation of cells with defined duration and intensity. Our results reveal that electropermeabilization becomes weaker with increased frequency in this range. In contrast, transfection efficiency with DNA reaches its maximum at medium frequencies (100-1000Hz) in the range. We postulate that the relationship between the transfection efficiency and the ac frequency is determined by combined effects from electrophoretic movement of DNA in the ac field, dependence of the DNA/membrane interaction on the ac frequency, and variation of transfection under different electropermeabilization intensities. The fact that ac electroporation in this frequency range yields high efficiency for transfection (up to ~71% for Chinese hamster ovary cells) and permeabilization suggests its potential for gene delivery.

  1. 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

  2. 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

  3. Philippines: decentralized approach shows results.

    PubMed

    1983-01-01

    In the Philippines several steps have been taken to meet the challenge of increasing population growth. Commencing with the Republic Act 6365, known as the Population Act (1971) program directives focus on achieving and maintaining population levels most conducive to the national welfare. In 1978 a Special Committee was constituted by the President to review the population program. Pursuant to the Committee's findings certain changes were adopted. The thrust is now towards longterm planning to ensure a more significant and perceptible demographic impact of development programs and policies. Increasing attention is paid to regional development and spatial distribution in the country. The 1978-82 Development Plan states more clearly the interaction between population and development. The National Economic and Development Authority, the central policy and planning agency of the government, takes charge of formulation and coordinating the broader aspects of population policy and integrating population with socioeconomic plans and policies. At present the National Economic and Development Authority (NEDA) is implementing a project known as the Population/Development Planning and Research (PDPR) project with financial support from the UN Fund for Population Activities (UNFPA). This project promotes and facilitates the integration of the population dimension in the planning process. It does this by maintaining linkages and instituting collaborative mechanisms with the different NEDA regional offices and sectoral ministries. It also trains government planners in ways of integrating population concerns into the development plan. PDPR promotes the use of population and development research for planning purposes and policy formation. The Philippine Development Plan, 1978-82, recognized that an improvement in the level of 1 sector reinforces the performance of the other sectors. Since the establishment of the National Population Program 12 years ago, population and family planning have been successfully integrated with various development sectors, notably, labor, health, and education. Through the policies of integration, multiagency participation, and partnership of the public and private sectors, the Commission on Population uses existing development programs of government and private organizations as vehicles for family planning information and services and shares the responsibility of implementing all facets of the population program with various participating agencies in the government and private sector.

  4. Accuracy assessment of GPS satellite orbits

    NASA Technical Reports Server (NTRS)

    Schutz, B. E.; Tapley, B. D.; Abusali, P. A. M.; Ho, C. S.

    1991-01-01

    GPS orbit accuracy is examined using several evaluation procedures. The existence is shown of unmodeled effects which correlate with the eclipsing of the sun. The ability to obtain geodetic results that show an accuracy of 1-2 parts in 10 to the 8th or better has not diminished.

  5. Diagnostic Accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma;results from a high burden country

    PubMed Central

    Shazlee, Muhammad Kashif; Ali, Muhammad; SaadAhmed, Muhammad; Hussain, Ammad; Hameed, Kamran; Lutfi, Irfan Amjad; Khan, Muhammad Tahir

    2016-01-01

    Objective: To study the diagnostic accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma. Methods: A total of 61 patients with 63 ocular injuries were assessed during July 2013 to January 2014. All patients were referred to the department of Radiology from Emergency Room since adequate clinical assessment of the fundus was impossible because of the presence of opaque ocular media. Based on radiological diagnosis, the patients were provided treatment (surgical or medical). Clinical diagnosis was confirmed during surgical procedures or clinical follow-up. Results: A total of 63 ocular injuries were examined in 61 patients. The overall sensitivity was 91.5%, Specificity was 98.87%, Positive predictive value was 87.62 and Negative predictive value was 99%. Conclusion: Ultrasound B-scan is a sensitive, non invasive and rapid way of assessing intraocular damage caused by blunt or penetrating eye injuries. PMID:27182245

  6. 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…

  7. First results using a new technology for measuring masses of very short-lived nuclides with very high accuracy: The MISTRAL program at ISOLDE

    SciTech Connect

    Monsanglant, C.; Audi, G.; Conreur, G.; Cousin, R.; Doubre, H.; Jacotin, M.; Henry, S.; Kepinski, J.-F.; Lunney, D.; Saint Simon, M. de; Thibault, C.; Toader, C.; Bollen, G.; Lebee, G.; Scheidenberger, C.; Borcea, C.; Duma, M.; Kluge, H.-J.; Le Scornet, G.

    1999-11-16

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na, Mg, Al, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  8. Accuracy in optical overlay metrology

    NASA Astrophysics Data System (ADS)

    Bringoltz, Barak; Marciano, Tal; Yaziv, Tal; DeLeeuw, Yaron; Klein, Dana; Feler, Yoel; Adam, Ido; Gurevich, Evgeni; Sella, Noga; Lindenfeld, Ze'ev; Leviant, Tom; Saltoun, Lilach; Ashwal, Eltsafon; Alumot, Dror; Lamhot, Yuval; Gao, Xindong; Manka, James; Chen, Bryan; Wagner, Mark

    2016-03-01

    In this paper we discuss the mechanism by which process variations determine the overlay accuracy of optical metrology. We start by focusing on scatterometry, and showing that the underlying physics of this mechanism involves interference effects between cavity modes that travel between the upper and lower gratings in the scatterometry target. A direct result is the behavior of accuracy as a function of wavelength, and the existence of relatively well defined spectral regimes in which the overlay accuracy and process robustness degrades (`resonant regimes'). These resonances are separated by wavelength regions in which the overlay accuracy is better and independent of wavelength (we term these `flat regions'). The combination of flat and resonant regions forms a spectral signature which is unique to each overlay alignment and carries certain universal features with respect to different types of process variations. We term this signature the `landscape', and discuss its universality. Next, we show how to characterize overlay performance with a finite set of metrics that are available on the fly, and that are derived from the angular behavior of the signal and the way it flags resonances. These metrics are used to guarantee the selection of accurate recipes and targets for the metrology tool, and for process control with the overlay tool. We end with comments on the similarity of imaging overlay to scatterometry overlay, and on the way that pupil overlay scatterometry and field overlay scatterometry differ from an accuracy perspective.

  9. MHC-congenic mice (C57BL/6J and B6-H-2K) show differences in speed but not accuracy in learning the Hebb-Williams Maze.

    PubMed

    Stanford, Lianne; Brown, Richard E

    2003-09-15

    We compared spatial learning and memory in male and female mice of two MHC-congenic strains (C57BL/6J and B6-H-2K) in two versions of the Hebb-Williams Maze. In the food-reward paradigm, males required fewer sessions to learn than females, but there were no strain differences in acquisition. There were no strain or sex differences in the number of errors during the test phase, but the B6-H-2K mice reached the goal box faster than the C57BL/6J mice. In the water-escape paradigm, the C57BL/6J mice required more sessions than the B6-H-2K mice during acquisition. There were no strain or sex differences in the number of errors or in the latency to swim to the goal box in the test phase of the water-escape task. There were no significant correlations between the number of sessions to learn the two mazes; the number of errors made or the latencies to reach the goal box in each maze. These results indicate that these two strains show differences in performance in the Hebb-Williams Maze, but do not differ in cognitive ability.

  10. 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.

  11. 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.

  12. Classification accuracy improvement

    NASA Technical Reports Server (NTRS)

    Kistler, R.; Kriegler, F. J.

    1977-01-01

    Improvements made in processing system designed for MIDAS (prototype multivariate interactive digital analysis system) effects higher accuracy in classification of pixels, resulting in significantly-reduced processing time. Improved system realizes cost reduction factor of 20 or more.

  13. 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.

  14. "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 state's best…

  15. First Results Using a New Technology for Measuring Masses of Very Short-Lived Nuclides with Very High Accuracy: the MISTRAL Program at ISOLDE

    SciTech Connect

    C. Monsanglant; C. Toader; G. Audi; G. Bollen; C. Borcea; G. Conreur; R. Cousin; H. Doubre; M. Duma; M. Jacotin; S. Henry; J.-F. Kepinski; H.-J. Kluge; G. Lebee; G. Le Scornet; D. Lunney; M. de Saint Simon; C. Scheidenberger; C. Thibault

    1999-12-31

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na{clubsuit}, Mg, Al{clubsuit}, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  16. 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...

  17. 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

  18. THE ACCURACY OF USING THE ULYSSES RESULT OF THE SPATIAL INVARIANCE OF THE RADIAL HELIOSPHERIC FIELD TO COMPUTE THE OPEN SOLAR FLUX

    SciTech Connect

    Lockwood, M.; Owens, M.

    2009-08-20

    We survey observations of the radial magnetic field in the heliosphere as a function of position, sunspot number, and sunspot cycle phase. We show that most of the differences between pairs of simultaneous observations, normalized using the square of the heliocentric distance and averaged over solar rotations, are consistent with the kinematic 'flux excess' effect whereby the radial component of the frozen-in heliospheric field is increased by longitudinal solar wind speed structure. In particular, the survey shows that, as expected, the flux excess effect at high latitudes is almost completely absent during sunspot minimum but is almost the same as within the streamer belt at sunspot maximum. We study the uncertainty inherent in the use of the Ulysses result that the radial field is independent of heliographic latitude in the computation of the total open solar flux: we show that after the kinematic correction for the excess flux effect has been made it causes errors that are smaller than 4.5%, with a most likely value of 2.5%. The importance of this result for understanding temporal evolution of the open solar flux is reviewed.

  19. 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.

  20. Magnetic Sphincter Augmentation for Gastroesophageal Reflux at 5 Years: Final Results of a Pilot Study Show Long-Term Acid Reduction and Symptom Improvement

    PubMed Central

    Saino, Greta; Bonavina, Luigi; Lipham, John C.; Dunn, Daniel

    2015-01-01

    Abstract Background: As previously reported, the magnetic sphincter augmentation device (MSAD) preserves gastric anatomy and results in less severe side effects than traditional antireflux surgery. The final 5-year results of a pilot study are reported here. Patients and Methods: A prospective, multicenter study evaluated safety and efficacy of the MSAD for 5 years. Prior to MSAD placement, patients had abnormal esophageal acid and symptoms poorly controlled by proton pump inhibitors (PPIs). Patients served as their own control, which allowed comparison between baseline and postoperative measurements to determine individual treatment effect. At 5 years, gastroesophageal reflux disease (GERD)-Health Related Quality of Life (HRQL) questionnaire score, esophageal pH, PPI use, and complications were evaluated. Results: Between February 2007 and October 2008, 44 patients (26 males) had an MSAD implanted by laparoscopy, and 33 patients were followed up at 5 years. Mean total percentage of time with pH <4 was 11.9% at baseline and 4.6% at 5 years (P < .001), with 85% of patients achieving pH normalization or at least a 50% reduction. Mean total GERD-HRQL score improved significantly from 25.7 to 2.9 (P < .001) when comparing baseline and 5 years, and 93.9% of patients had at least a 50% reduction in total score compared with baseline. Complete discontinuation of PPIs was achieved by 87.8% of patients. No complications occurred in the long term, including no device erosions or migrations at any point. Conclusions: Based on long-term reduction in esophageal acid, symptom improvement, and no late complications, this study shows the relative safety and efficacy of magnetic sphincter augmentation for GERD. PMID:26437027

  1. 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

  2. Rapamycin and Chloroquine: The In Vitro and In Vivo Effects of Autophagy-Modifying Drugs Show Promising Results in Valosin Containing Protein Multisystem Proteinopathy

    PubMed Central

    Nalbandian, Angèle; Llewellyn, Katrina J.; Nguyen, Christopher; Yazdi, Puya G.; Kimonis, Virginia E.

    2015-01-01

    Mutations in the valosin containing protein (VCP) gene cause hereditary Inclusion body myopathy (hIBM) associated with Paget disease of bone (PDB), frontotemporal dementia (FTD), more recently termed multisystem proteinopathy (MSP). Affected individuals exhibit scapular winging and die from progressive muscle weakness, and cardiac and respiratory failure, typically in their 40s to 50s. Histologically, patients show the presence of rimmed vacuoles and TAR DNA-binding protein 43 (TDP-43)-positive large ubiquitinated inclusion bodies in the muscles. We have generated a VCPR155H/+ mouse model which recapitulates the disease phenotype and impaired autophagy typically observed in patients with VCP disease. Autophagy-modifying agents, such as rapamycin and chloroquine, at pharmacological doses have previously shown to alter the autophagic flux. Herein, we report results of administration of rapamycin, a specific inhibitor of the mechanistic target of rapamycin (mTOR) signaling pathway, and chloroquine, a lysosomal inhibitor which reverses autophagy by accumulating in lysosomes, responsible for blocking autophagy in 20-month old VCPR155H/+ mice. Rapamycin-treated mice demonstrated significant improvement in muscle performance, quadriceps histological analysis, and rescue of ubiquitin, and TDP-43 pathology and defective autophagy as indicated by decreased protein expression levels of LC3-I/II, p62/SQSTM1, optineurin and inhibiting the mTORC1 substrates. Conversely, chloroquine-treated VCPR155H/+ mice revealed progressive muscle weakness, cytoplasmic accumulation of TDP-43, ubiquitin-positive inclusion bodies and increased LC3-I/II, p62/SQSTM1, and optineurin expression levels. Our in vitro patient myoblasts studies treated with rapamycin demonstrated an overall improvement in the autophagy markers. Targeting the mTOR pathway ameliorates an increasing list of disorders, and these findings suggest that VCP disease and related neurodegenerative multisystem proteinopathies can

  3. Modeling upward brine migration through faults as a result of CO2 storage in the Northeast German Basin shows negligible salinization in shallow aquifers

    NASA Astrophysics Data System (ADS)

    Kuehn, M.; Tillner, E.; Kempka, T.; Nakaten, B.

    2012-12-01

    The geological storage of CO2 in deep saline formations may cause salinization of shallower freshwater resources by upward flow of displaced brine from the storage formation into potable groundwater. In this regard, permeable faults or fractures can serve as potential leakage pathways for upward brine migration. The present study uses a regional-scale 3D model based on real structural data of a prospective CO2 storage site in Northeastern Germany to determine the impact of compartmentalization and fault permeability on upward brine migration as a result of pressure elevation by CO2 injection. To evaluate the degree of salinization in the shallower aquifers, different fault leakage scenarios were carried out using a newly developed workflow in which the model grid from the software package Petrel applied for pre-processing is transferred to the reservoir simulator TOUGH2-MP/ECO2N. A discrete fault description is achieved by using virtual elements. A static 3D geological model of the CO2 storage site with an a real size of 40 km x 40 km and a thickness of 766 m was implemented. Subsequently, large-scale numerical multi-phase multi-component (CO2, NaCl, H2O) flow simulations were carried out on a high performance computing system. The prospective storage site, located in the Northeast German Basin is part of an anticline structure characterized by a saline multi-layer aquifer system. The NE and SW boundaries of the study area are confined by the Fuerstenwalde Gubener and the Lausitzer Abbruch fault zones represented by four discrete faults in the model. Two formations of the Middle Bunter were chosen to assess brine migration through faults triggered by an annual injection rate of 1.7 Mt CO2 into the lowermost formation over a time span of 20 years. In addition to varying fault permeabilities, different boundary conditions were applied to evaluate the effects of reservoir compartmentalization. Simulation results show that the highest pressurization within the storage

  4. 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…

  5. Optimizing Tsunami Forecast Model Accuracy

    NASA Astrophysics Data System (ADS)

    Whitmore, P.; Nyland, D. L.; Huang, P. Y.

    2015-12-01

    Recent tsunamis provide a means to determine the accuracy that can be expected of real-time tsunami forecast models. Forecast accuracy using two different tsunami forecast models are compared for seven events since 2006 based on both real-time application and optimized, after-the-fact "forecasts". Lessons learned by comparing the forecast accuracy determined during an event to modified applications of the models after-the-fact provide improved methods for real-time forecasting for future events. Variables such as source definition, data assimilation, and model scaling factors are examined to optimize forecast accuracy. Forecast accuracy is also compared for direct forward modeling based on earthquake source parameters versus accuracy obtained by assimilating sea level data into the forecast model. Results show that including assimilated sea level data into the models increases accuracy by approximately 15% for the events examined.

  6. Empathic Embarrassment Accuracy in Autism Spectrum Disorder.

    PubMed

    Adler, Noga; Dvash, Jonathan; Shamay-Tsoory, Simone G

    2015-06-01

    Empathic accuracy refers to the ability of perceivers to accurately share the emotions of protagonists. Using a novel task assessing embarrassment, the current study sought to compare levels of empathic embarrassment accuracy among individuals with autism spectrum disorders (ASD) with those of matched controls. To assess empathic embarrassment accuracy, we compared the level of embarrassment experienced by protagonists to the embarrassment felt by participants while watching the protagonists. The results show that while the embarrassment ratings of participants and protagonists were highly matched among controls, individuals with ASD failed to exhibit this matching effect. Furthermore, individuals with ASD rated their embarrassment higher than controls when viewing themselves and protagonists on film, but not while performing the task itself. These findings suggest that individuals with ASD tend to have higher ratings of empathic embarrassment, perhaps due to difficulties in emotion regulation that may account for their impaired empathic accuracy and aberrant social behavior. PMID:25732043

  7. Optimal design of robot accuracy compensators

    SciTech Connect

    Zhuang, H.; Roth, Z.S. . Robotics Center and Electrical Engineering Dept.); Hamano, Fumio . Dept. of Electrical Engineering)

    1993-12-01

    The problem of optimal design of robot accuracy compensators is addressed. Robot accuracy compensation requires that actual kinematic parameters of a robot be previously identified. Additive corrections of joint commands, including those at singular configurations, can be computed without solving the inverse kinematics problem for the actual robot. This is done by either the damped least-squares (DLS) algorithm or the linear quadratic regulator (LQR) algorithm, which is a recursive version of the DLS algorithm. The weight matrix in the performance index can be selected to achieve specific objectives, such as emphasizing end-effector's positioning accuracy over orientation accuracy or vice versa, or taking into account proximity to robot joint travel limits and singularity zones. The paper also compares the LQR and the DLS algorithms in terms of computational complexity, storage requirement, and programming convenience. Simulation results are provided to show the effectiveness of the algorithms.

  8. 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.

  9. 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.

  10. Transitioning from preclinical to clinical chemopreventive assessments of lyophilized black raspberries: interim results show berries modulate markers of oxidative stress in Barrett's esophagus patients.

    PubMed

    Kresty, Laura A; Frankel, Wendy L; Hammond, Cynthia D; Baird, Maureen E; Mele, Jennifer M; Stoner, Gary D; Fromkes, John J

    2006-01-01

    Increased fruit and vegetable consumption is associated with decreased risk of a number of cancers of epithelial origin, including esophageal cancer. Dietary administration of lyophilized black raspberries (LBRs) has significantly inhibited chemically induced oral, esophageal, and colon carcinogenesis in animal models. Likewise, berry extracts added to cell cultures significantly inhibited cancer-associated processes. Positive results in preclinical studies have supported further investigation of berries and berry extracts in high-risk human cohorts, including patients with existing premalignancy or patients at risk for cancer recurrence. We are currently conducting a 6-mo chemopreventive pilot study administering 32 or 45 g (female and male, respectively) of LBRs to patients with Barrett's esophagus (BE), a premalignant esophageal condition in which the normal stratified squamous epithelium changes to a metaplastic columnar-lined epithelium. BE's importance lies in the fact that it confers a 30- to 40-fold increased risk for the development of esophageal adenocarcinoma, a rapidly increasing and extremely deadly malignancy. This is a report on interim findings from 10 patients. To date, the results support that daily consumption of LBRs promotes reductions in the urinary excretion of two markers of oxidative stress, 8-epi-prostaglandin F2alpha (8-Iso-PGF2) and, to a lesser more-variable extent, 8-hydroxy-2'-deoxyguanosine (8-OHdG), among patients with BE.

  11. The Accuracy of Academic Gender Stereotypes.

    ERIC Educational Resources Information Center

    Beyer, Sylvia

    1999-01-01

    Assessed the accuracy of academic gender stereotypes by asking 265 college students to estimate the percentage of male and female students and their grade point averages (GPAs) and comparing these to the actual percentage of male and female students and GPAs. Results show the inaccuracies of academic gender stereotypes. (SLD)

  12. 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.

  13. 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.

  14. 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)

  15. [Ovarian tumours--accuracy of frozen section diagnosis].

    PubMed

    Ivanov, S; Ivanov, S; Khadzhiolov, N

    2005-01-01

    A retrospective study of 450 ovarian biopsy results were examined for the period of 1998 till 2004 to evaluate the accuracy of frozen section diagnosis. In addition to this we performed a review of the literature for all previous studies in this field in order to study the accuracy rates of the different clinics throughout the world. The histhopathological results of the frozen section diagnosis were equal with the diagnosis of the paraffin blocks in 90%. The sensitivity rates for benign, malignant and borderline tumours, were 96%, 84% and 60% respectively. We had 10 patients (2,1%) false-positive results (overdiagnosed) and 26 (5,2%) false-negative results (underdiagnosed) in frozen section examinations. Frozen section examination of mucinous tumours showed hogher underdiagnosis--18%. The review of the literature showed that there is no significant difference in accuracy rates of frozen section diagnosis for benign and malignant ovarian tumours in relation with time. We found low accuracy rates for borderline tumours which was similar with most of the foreign publications. However the accuracy of the frozen section diagnosis is bettering with the time. As a result of this we conclude that the accuracy rates of the frozen section diagnosis for evaluation of the malignant and benign tumours is quite enough for correct diagnosis. Since accuracy rates for borderline ovarian tumours are low we have to take care and attention of improvement in this field.

  16. 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.

  17. High accuracy time transfer synchronization

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

    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.

  18. 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

  19. Modeling Individual Differences in Response Time and Accuracy in Numeracy

    PubMed Central

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

    2015-01-01

    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

  20. 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.

  1. 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. PMID:27044032

  2. 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.

  3. 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.

  4. 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. PMID:25079676

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

    PubMed

    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

  6. 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…

  7. 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.

  8. Continuous glucose monitoring and trend accuracy: news about a trend compass.

    PubMed

    Signal, Matthew; Gottlieb, Rebecca; Le Compte, Aaron; Chase, J Geoffrey

    2014-09-01

    Continuous glucose monitoring (CGM) devices are being increasingly used to monitor glycemia in people with diabetes. One advantage with CGM is the ability to monitor the trend of sensor glucose (SG) over time. However, there are few metrics available for assessing the trend accuracy of CGM devices. The aim of this study was to develop an easy to interpret tool for assessing trend accuracy of CGM data. SG data from CGM were compared to hourly blood glucose (BG) measurements and trend accuracy was quantified using the dot product. Trend accuracy results are displayed on the Trend Compass, which depicts trend accuracy as a function of BG. A trend performance table and Trend Index (TI) metric are also proposed. The Trend Compass was tested using simulated CGM data with varying levels of error and variability, as well as real clinical CGM data. The results show that the Trend Compass is an effective tool for differentiating good trend accuracy from poor trend accuracy, independent of glycemic variability. Furthermore, the real clinical data show that the Trend Compass assesses trend accuracy independent of point bias error. Finally, the importance of assessing trend accuracy as a function of BG level is highlighted in a case example of low and falling BG data, with corresponding rising SG data. This study developed a simple to use tool for quantifying trend accuracy. The resulting trend accuracy is easily interpreted on the Trend Compass plot, and if required, performance table and TI metric. PMID:24876437

  9. 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...

  10. Orbit accuracy assessment for Seasat

    NASA Technical Reports Server (NTRS)

    Schutz, B. E.; Tapley, B. D.

    1980-01-01

    Laser range measurements are used to determine the orbit of Seasat during the period from July 28, 1978, to Aug. 14, 1978, and the influence of the gravity field, atmospheric drag, and solar radiation pressure on the orbit accuracy is investigated. It is noted that for the orbits of three-day duration, little distinction can be made between the influence of different atmospheric models. It is found that the special Seasat gravity field PGS-S3 is most consistent with the data for three-day orbits, but an unmodeled systematic effect in radiation pressure is noted. For orbits of 18-day duration, little distinction can be made between the results derived from the PGS gravity fields. It is also found that the geomagnetic field is an influential factor in the atmospheric modeling during this time period. Seasat altimeter measurements are used to determine the accuracy of the altimeter measurement time tag and to evaluate the orbital accuracy.

  11. Geometric accuracy of three-dimensional molecular overlays.

    PubMed

    Chen, Qi; Higgs, Richard E; Vieth, Michal

    2006-01-01

    This study examines the dependence of molecular alignment accuracy on a variety of factors including the choice of molecular template, alignment method, conformational flexibility, and type of protein target. We used eight test systems for which X-ray data on 145 ligand-protein complexes were available. The use of X-ray structures allowed an unambiguous assignment of bioactive overlays for each compound set. The alignment accuracy depended on multiple factors and ranged from 6% for flexible overlays to 73% for X-ray rigid overlays, when the conformation of the template ligand came from X-ray structures. The dependence of the overlay accuracy on the choice of templates and molecules to be aligned was found to be the most significant factor in six and seven of the eight ligand-protein complex data sets, respectively. While finding little preference for the overlay method, we observed that the introduction of molecule flexibility resulted in a decrease of overlay accuracy in 50% of the cases. We derived rules to maximize the accuracy of alignment, leading to a more than 2-fold improvement in accuracy (from 19% to 48%). The rules also allowed the identification of compounds with a low (<5%) chance to be correctly aligned. Last, the accuracy of the alignment derived without any utilization of X-ray conformers varied from <1% for the human immunodeficiency virus data set to 53% for the trypsin data set. We found that the accuracy was directly proportional to the product of the overlay accuracy from the templates in their bioactive conformations and the chance of obtaining the correct bioactive conformation of the templates. This study generates a much needed benchmark for the expectations of molecular alignment accuracy and shows appropriate usages and best practices to maximize hypothesis generation success.

  12. Accuracy of TCP performance models

    NASA Astrophysics Data System (ADS)

    Schwefel, Hans Peter; Jobmann, Manfred; Hoellisch, Daniel; Heyman, Daniel P.

    2001-07-01

    Despite the fact that most of todays' Internet traffic is transmitted via the TCP protocol, the performance behavior of networks with TCP traffic is still not well understood. Recent research activities have lead to a number of performance models for TCP traffic, but the degree of accuracy of these models in realistic scenarios is still questionable. This paper provides a comparison of the results (in terms of average throughput per connection) of three different `analytic' TCP models: I. the throughput formula in [Padhye et al. 98], II. the modified Engset model of [Heyman et al. 97], and III. the analytic TCP queueing model of [Schwefel 01] that is a packet based extension of (II). Results for all three models are computed for a scenario of N identical TCP sources that transmit data in individual TCP connections of stochastically varying size. The results for the average throughput per connection in the analytic models are compared with simulations of detailed TCP behavior. All of the analytic models are expected to show deficiencies in certain scenarios, since they neglect highly influential parameters of the actual real simulation model: The approach of Model (I) and (II) only indirectly considers queueing in bottleneck routers, and in certain scenarios those models are not able to adequately describe the impact of buffer-space, neither qualitatively nor quantitatively. Furthermore, (II) is insensitive to the actual distribution of the connection sizes. As a consequence, their prediction would also be insensitive of so-called long-range dependent properties in the traffic that are caused by heavy-tailed connection size distributions. The simulation results show that such properties cannot be neglected for certain network topologies: LRD properties can even have counter-intuitive impact on the average goodput, namely the goodput can be higher for small buffer-sizes.

  13. Accuracy of forecasts in strategic intelligence

    PubMed Central

    Mandel, David R.; Barnes, Alan

    2014-01-01

    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. PMID:25024176

  14. 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.

  15. 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.

  16. 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

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

    PubMed

    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

  18. 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.

  19. Vibrational Spectroscopy of HD{sup +} with 2-ppb Accuracy

    SciTech Connect

    Koelemeij, J. C. J.; Roth, B.; Wicht, A.; Ernsting, I.; Schiller, S.

    2007-04-27

    By measurement of the frequency of a vibrational overtone transition in the molecular hydrogen ion HD{sup +}, we demonstrate the first optical spectroscopy of trapped molecular ions with submegahertz accuracy. We use a diode laser, locked to a stable frequency comb, to perform resonance-enhanced multiphoton dissociation spectroscopy on sympathetically cooled HD{sup +} ions at 50 mK. The achieved 2-ppb relative accuracy is a factor of 150 higher than previous results for HD{sup +}, and the measured transition frequency agrees well with recent high-accuracy ab initio calculations, which include high-order quantum electrodynamic effects. We also show that our method bears potential for achieving considerably higher accuracy and may, if combined with slightly improved theoretical calculations, lead to a new and improved determination of the electron-proton mass ratio.

  20. Ultrasonic flowmeters undergo accuracy, repeatability tests

    SciTech Connect

    Grimley, T.A.

    1996-12-23

    Two commercially available multipath ultrasonic flowmeters have undergone tests at Gas Research Institute`s metering research facility (MRF) at Southwest Research institute in San Antonio. The tests were conducted in baseline and disturbed-flow installations to assess baseline accuracy and repeatability over a range of flowrates and pressures. Results show the test meters are capable of accuracies within a 1% tolerance and with repeatability of better than 0.25% when the flowrate is greater than about 5% of capacity. The data also indicates that pressure may have an effect on meter error. Results further suggest that both the magnitude and character of errors introduced by flow disturbances are a function of meter design. Shifts of up to 0.6% were measured for meters installed 10D from a tee (1D = 1 pipe diameter). Better characterization of the effects of flow disturbances on measurement accuracy is needed to define more accurately the upstream piping requirements necessary to achieve meter performance within a specified tolerance. The paper discusses reduced station costs, test methods, baseline tests, effect of pressure, speed of sound, and disturbance tests.

  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

    Accuracy assessment is an extensive effort that requires seasonal field personnel and equipment, data entry, analyses, and post processing—tasks that are costly and time consuming. The geospatial team at the UMESC has suggested a validation process for understanding the accuracy of the spatial datasets, which will be tested on at least some areas of the UMRS. Validation is not a true verification of map-class type in the field; however, it can provide the user of the map with useful information that is similar to a field AA

  2. Metamemory accuracy: effects of feedback and the stability of individual differences.

    PubMed

    Thompson, W B

    1998-01-01

    This study addressed two questions about metamemory accuracy: how feedback about recall performance affects confidence-recall accuracy and whether individual differences in confidence-recall accuracy are stable across different sets of test items. College students answered general knowledge questions and made confidence ratings about the correctness of the answers. Half the students were told whether their answers were correct. All students answered half the questions a second time. The results show that feedback did not produce a general improvement in metamemory accuracy; the improvement was specific to the questions for which feedback was provided. Also, individual students' metamemory accuracy showed moderate alternate-forms stability when each test was made up of 250 items. Therefore, researchers studying individual differences in metamemory accuracy on recall tasks should use tests that yield several hundred responses. PMID:9624702

  3. 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.

  4. Drawing accuracy measured using polygons

    NASA Astrophysics Data System (ADS)

    Carson, Linda; Millard, Matthew; Quehl, Nadine; Danckert, James

    2013-03-01

    The study of drawing, for its own sake and as a probe into human visual perception, generally depends on ratings by human critics and self-reported expertise of the drawers. To complement those approaches, we have developed a geometric approach to analyzing drawing accuracy, one whose measures are objective, continuous and performance-based. Drawing geometry is represented by polygons formed by landmark points found in the drawing. Drawing accuracy is assessed by comparing the geometric properties of polygons in the drawn image to the equivalent polygon in a ground truth photo. There are four distinct properties of a polygon: its size, its position, its orientation and the proportionality of its shape. We can decompose error into four components and investigate how each contributes to drawing performance. We applied a polygon-based accuracy analysis to a pilot data set of representational drawings and found that an expert drawer outperformed a novice on every dimension of polygon error. The results of the pilot data analysis correspond well with the apparent quality of the drawings, suggesting that the landmark and polygon analysis is a method worthy of further study. Applying this geometric analysis to a within-subjects comparison of accuracy in the positive and negative space suggests there is a trade-off on dimensions of error. The performance-based analysis of geometric deformations will allow the study of drawing accuracy at different levels of organization, in a systematic and quantitative manner. We briefly describe the method and its potential applications to research in drawing education and visual perception.

  5. 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. PMID:25244469

  6. 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.

  7. Accuracy in prescriptions compounded by pharmacy students.

    PubMed

    Shrewsbury, R P; Deloatch, K H

    1998-01-01

    Most compounded prescriptions are not analyzed to determine the accuracy of the employed instruments and procedures. The assumption is that the compounded prescription will be +/- 5% the labeled claim. Two classes of School of Pharmcacy students who received repeated instruction and supervision on proper compounding techniques and procedures were assessed to determine their accuracy of compounding a diphenhydramine hydrochloride prescription. After two attempts, only 62% to 68% of the students could compound the prescription within +/- 5% the labeled claim; but 84% to 96% could attain an accuracy of +/- 10%. The results suggest that an accuracy of +/- 10% labeled claim is the least variation a pharmacist can expect when extemporaneously compounding prescriptions.

  8. An evaluation of information retrieval accuracy with simulated OCR output

    SciTech Connect

    Croft, W.B.; Harding, S.M.; Taghva, K.; Borsack, J.

    1994-12-31

    Optical Character Recognition (OCR) is a critical part of many text-based applications. Although some commercial systems use the output from OCR devices to index documents without editing, there is very little quantitative data on the impact of OCR errors on the accuracy of a text retrieval system. Because of the difficulty of constructing test collections to obtain this data, we have carried out evaluation using simulated OCR output on a variety of databases. The results show that high quality OCR devices have little effect on the accuracy of retrieval, but low quality devices used with databases of short documents can result in significant degradation.

  9. 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%.

  10. 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%. PMID:26192526

  11. 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.

  12. 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. PMID:25273491

  13. Accuracy of Aerodynamic Model Parameters Estimated from Flight Test Data

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.; Klein, Vladislav

    1997-01-01

    An important put of building mathematical models based on measured date is calculating the accuracy associated with statistical estimates of the model parameters. Indeed, without some idea of this accuracy, the parameter estimates themselves have limited value. An expression is developed for computing quantitatively correct parameter accuracy measures for maximum likelihood parameter estimates when the output residuals are colored. This result is important because experience in analyzing flight test data reveals that the output residuals from maximum likelihood estimation are almost always colored. The calculations involved can be appended to conventional maximum likelihood estimation algorithms. Monte Carlo simulation runs were used to show that parameter accuracy measures from the new technique accurately reflect the quality of the parameter estimates from maximum likelihood estimation without the need for correction factors or frequency domain analysis of the output residuals. The technique was applied to flight test data from repeated maneuvers flown on the F-18 High Alpha Research Vehicle. As in the simulated cases, parameter accuracy measures from the new technique were in agreement with the scatter in the parameter estimates from repeated maneuvers, whereas conventional parameter accuracy measures were optimistic.

  14. High accuracy flexural hinge development

    NASA Astrophysics Data System (ADS)

    Santos, I.; Ortiz de Zárate, I.; Migliorero, G.

    2005-07-01

    This document provides a synthesis of the technical results obtained in the frame of the HAFHA (High Accuracy Flexural Hinge Assembly) development performed by SENER (in charge of design, development, manufacturing and testing at component and mechanism levels) with EADS Astrium as subcontractor (in charge of doing an inventory of candidate applications among existing and emerging projects, establishing the requirements and perform system level testing) under ESA contract. The purpose of this project has been to develop a competitive technology for a flexural pivot, usuable in highly accurate and dynamic pointing/scanning mechanisms. Compared with other solutions (e.g. magnetic or ball bearing technologies) flexural hinges are the appropriate technology for guiding with accuracy a mobile payload over a limited angular ranges around one rotation axes.

  15. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, D.; Hashmall, J.

    1994-01-01

    This paper summarizes a compilation of attitude determination accuracies attained by a number of satellites supported by the Goddard Space Flight Center Flight Dynamics Facility. The compilation is designed to assist future mission planners in choosing and placing attitude hardware and selecting the attitude determination algorithms needed to achieve given accuracy requirements. The major goal of the compilation is to indicate realistic accuracies achievable using a given sensor complement based on mission experience. It is expected that the use of actual spacecraft experience will make the study especially useful for mission design. A general description of factors influencing spacecraft attitude accuracy is presented. These factors include determination algorithms, inertial reference unit characteristics, and error sources that can affect measurement accuracy. Possible techniques for mitigating errors are also included. Brief mission descriptions are presented with the attitude accuracies attained, grouped by the sensor pairs used in attitude determination. The accuracies for inactive missions represent a compendium of missions report results, and those for active missions represent measurements of attitude residuals. Both three-axis and spin stabilized missions are included. Special emphasis is given to high-accuracy sensor pairs, such as two fixed-head star trackers (FHST's) and fine Sun sensor plus FHST. Brief descriptions of sensor design and mode of operation are included. Also included are brief mission descriptions and plots summarizing the attitude accuracy attained using various sensor complements.

  16. Measures of Diagnostic Accuracy: Basic Definitions

    PubMed Central

    Šimundić, Ana-Maria

    2009-01-01

    Diagnostic accuracy relates to the ability of a test to discriminate between the target condition and health. This discriminative potential can be quantified by the measures of diagnostic accuracy such as sensitivity and specificity, predictive values, likelihood ratios, the area under the ROC curve, Youden's index and diagnostic odds ratio. Different measures of diagnostic accuracy relate to the different aspects of diagnostic procedure: while some measures are used to assess the discriminative property of the test, others are used to assess its predictive ability. Measures of diagnostic accuracy are not fixed indicators of a test performance, some are very sensitive to the disease prevalence, while others to the spectrum and definition of the disease. Furthermore, measures of diagnostic accuracy are extremely sensitive to the design of the study. Studies not meeting strict methodological standards usually over- or under-estimate the indicators of test performance as well as they limit the applicability of the results of the study. STARD initiative was a very important step toward the improvement the quality of reporting of studies of diagnostic accuracy. STARD statement should be included into the Instructions to authors by scientific journals and authors should be encouraged to use the checklist whenever reporting their studies on diagnostic accuracy. Such efforts could make a substantial difference in the quality of reporting of studies of diagnostic accuracy and serve to provide the best possible evidence to the best for the patient care. This brief review outlines some basic definitions and characteristics of the measures of diagnostic accuracy.

  17. 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.

  18. 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

  19. Accuracy of land surface elevation from CALIPSO mission data

    NASA Astrophysics Data System (ADS)

    Lu, Xiaomei; Hu, Yongxiang

    2015-03-01

    We assess the accuracy of land surface elevation retrieved from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission through comparisons with the U.S. Geological Survey National Elevation Dataset (NED), Shuttle Radar Topography Mission (SRTM), and the altimetry product from the Geoscience Laser Altimeter System onboard the Ice, Cloud, and Land Elevation Satellite (ICESat). The vertical accuracy of the CALIPSO-derived land surface elevation was tested against these three datasets for about 16 million lidar shots over the continental United States. The results show that the CALIPSO-derived elevation was highly correlated with the elevation result from the NED, SRTM, and ICESat datasets. The overall absolute vertical accuracies of the CALIPSO-derived land surface elevation expressed as the root mean square error (RMSE) are 5.58 and 5.90 m when compared with the SRTM and NED results, respectively. Lower accuracy of the CALIPSO-derived land surface elevation was achieved by comparison with the ICESat results (8.35-m RMSE), primarily due to the several kilometers distance between the CALIPSO and ICESat ground footprints. The results show that the variability in terrain, vegetation, canopy, and footprint size can all influence comparisons between the CALIPSO-derived elevation and the results obtained from NED, SRTM, and ICESat datasets.

  20. 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.

  1. 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.

  2. 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.

  3. Accuracy analysis and design of A3 parallel spindle head

    NASA Astrophysics Data System (ADS)

    Ni, Yanbing; Zhang, Biao; Sun, Yupeng; Zhang, Yuan

    2016-03-01

    As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focused on the accuracy problem of parallel mechanisms, but in terms of controlling the errors and improving the accuracy in the stage of design and manufacturing, further efforts are required. Aiming at the accuracy design of a 3-DOF parallel spindle head(A3 head), its error model, sensitivity analysis and tolerance allocation are investigated. Based on the inverse kinematic analysis, the error model of A3 head is established by using the first-order perturbation theory and vector chain method. According to the mapping property of motion and constraint Jacobian matrix, the compensatable and uncompensatable error sources which affect the accuracy in the end-effector are separated. Furthermore, sensitivity analysis is performed on the uncompensatable error sources. The sensitivity probabilistic model is established and the global sensitivity index is proposed to analyze the influence of the uncompensatable error sources on the accuracy in the end-effector of the mechanism. The results show that orientation error sources have bigger effect on the accuracy in the end-effector. Based upon the sensitivity analysis results, the tolerance design is converted into the issue of nonlinearly constrained optimization with the manufacturing cost minimum being the optimization objective. By utilizing the genetic algorithm, the allocation of the tolerances on each component is finally determined. According to the tolerance allocation results, the tolerance ranges of ten kinds of geometric error sources are obtained. These research achievements can provide fundamental guidelines for component manufacturing and assembly of this kind of parallel mechanisms.

  4. Cued Speech Transliteration: Effects of Speaking Rate and Lag Time on Production Accuracy.

    PubMed

    Krause, Jean C; Tessler, Morgan P

    2016-10-01

    Many deaf and hard-of-hearing children rely on interpreters to access classroom communication. Although the exact level of access provided by interpreters in these settings is unknown, it is likely to depend heavily on interpreter accuracy (portion of message correctly produced by the interpreter) and the factors that govern interpreter accuracy. In this study, the accuracy of 12 Cued Speech (CS) transliterators with varying degrees of experience was examined at three different speaking rates (slow, normal, fast). Accuracy was measured with a high-resolution, objective metric in order to facilitate quantitative analyses of the effect of each factor on accuracy. Results showed that speaking rate had a large negative effect on accuracy, caused primarily by an increase in omitted cues, whereas the effect of lag time on accuracy, also negative, was quite small and explained just 3% of the variance. Increased experience level was generally associated with increased accuracy; however, high levels of experience did not guarantee high levels of accuracy. Finally, the overall accuracy of the 12 transliterators, 54% on average across all three factors, was low enough to raise serious concerns about the quality of CS transliteration services that (at least some) children receive in educational settings. PMID:27221370

  5. 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

  6. Evidence for Enhanced Interoceptive Accuracy in Professional Musicians.

    PubMed

    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. Comparative study of application accuracy of two frameless neuronavigation systems: experimental error assessment quantifying registration methods and clinically influencing factors.

    PubMed

    Paraskevopoulos, Dimitrios; Unterberg, Andreas; Metzner, Roland; Dreyhaupt, Jens; Eggers, Georg; Wirtz, Christian Rainer

    2010-04-01

    This study aimed at comparing the accuracy of two commercial neuronavigation systems. Error assessment and quantification of clinical factors and surface registration, often resulting in decreased accuracy, were intended. Active (Stryker Navigation) and passive (VectorVision Sky, BrainLAB) neuronavigation systems were tested with an anthropomorphic phantom with a deformable layer, simulating skin and soft tissue. True coordinates measured by computer numerical control were compared with coordinates on image data and during navigation, to calculate software and system accuracy respectively. Comparison of image and navigation coordinates was used to evaluate navigation accuracy. Both systems achieved an overall accuracy of <1.5 mm. Stryker achieved better software accuracy, whereas BrainLAB better system and navigation accuracy. Factors with conspicuous influence (P<0.01) were imaging, instrument replacement, sterile cover drape and geometry of instruments. Precision data indicated by the systems did not reflect measured accuracy in general. Surface matching resulted in no improvement of accuracy, confirming former studies. Laser registration showed no differences compared to conventional pointers. Differences between the two systems were limited. Surface registration may improve inaccurate point-based registrations but does not in general affect overall accuracy. Accuracy feedback by the systems does not always match with true target accuracy and requires critical evaluation from the surgeon.

  8. 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.

  9. New analytical algorithm for overlay accuracy

    NASA Astrophysics Data System (ADS)

    Ham, Boo-Hyun; Yun, Sangho; Kwak, Min-Cheol; Ha, Soon Mok; Kim, Cheol-Hong; Nam, Suk-Woo

    2012-03-01

    total overlay error data is decomposed into two parts: the systematic error and the random error. And we tried to show both error components characteristic, systematic error has a good correlation with residual error by scanner condition, whereas, random error has a good correlation with residual error as going process steps. Furthermore, we demonstrate the practical using case with proposed method that shows the working of the high order method through systematic error. Our results show that to characterize an overlay data that is suitable for use in advanced technology nodes requires much more than just evaluating the conventional metrology metrics of TIS and TMU.

  10. 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

  11. A Holographic Road Show.

    ERIC Educational Resources Information Center

    Kirkpatrick, Larry D.; Rugheimer, Mac

    1979-01-01

    Describes the viewing sessions and the holograms of a holographic road show. The traveling exhibits, believed to stimulate interest in physics, include a wide variety of holograms and demonstrate several physical principles. (GA)

  12. 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.

  13. 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)

  14. Show What You Know

    ERIC Educational Resources Information Center

    Eccleston, Jeff

    2007-01-01

    Big things come in small packages. This saying came to the mind of the author after he created a simple math review activity for his fourth grade students. Though simple, it has proven to be extremely advantageous in reinforcing math concepts. He uses this activity, which he calls "Show What You Know," often. This activity provides the perfect…

  15. 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…

  16. 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…

  17. 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…

  18. Obesity in show cats.

    PubMed

    Corbee, R J

    2014-12-01

    Obesity is an important disease with a high prevalence in cats. Because obesity is related to several other diseases, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain cat breeds has been suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, 268 cats of 22 different breeds investigated by determining their body condition score (BCS) on a nine-point scale by inspection and palpation, at two different cat shows. Overall, 45.5% of the show cats had a BCS > 5, and 4.5% of the show cats had a BCS > 7. There were significant differences between breeds, which could be related to the breed standards. Most overweight and obese cats were in the neutered group. It warrants firm discussions with breeders and cat show judges to come to different interpretations of the standards in order to prevent overweight conditions in certain breeds from being the standard of beauty. Neutering predisposes for obesity and requires early nutritional intervention to prevent obese conditions. PMID:24612018

  19. 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…

  20. The Art Show

    ERIC Educational Resources Information Center

    Scolarici, Alicia

    2004-01-01

    This article describes what once was thought to be impossible--a formal art show extravaganza at an elementary school with 1,000 students, a Department of Defense Dependent School (DODDS) located overseas, on RAF Lakenheath, England. The dream of this this event involved the transformation of the school cafeteria into an elegant art show…

  1. 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)

  2. Factors affecting the accuracy of chest compression depth estimation

    PubMed Central

    Kang, Jung Hee; Cha, Won Chul; Chae, Minjung Kathy; Park, Hang A; Hwang, Sung Yeon; Jin, Sang Chan; Lee, Tae Rim; Shin, Tae Gun; Sim, Min Seob; Jo, Ik Joon; Song, Keun Jeong; Rhee, Joong Eui; Jeong, Yeon Kwon

    2014-01-01

    Objective We aimed to estimate the accuracy of visual estimation of chest compression depth and identify potential factors affecting accuracy. Methods This simulation study used a basic life support mannequin, the Ambu man. We recorded chest compression with 7 different depths from 1 to 7 cm. Each video clip was recorded for a cycle of compression. Three different viewpoints were used to record the video. After filming, 25 clips were randomly selected. Health care providers in an emergency department were asked to estimate the depth of compressions while watching the selected video clips. Examiner determinants such as experience and cardiopulmonary resuscitation training and environment determinants such as the location of the camera (examiner) were collected and analyzed. An estimated depth was considered correct if it was consistent with the one recorded. A multivariate analysis predicting the accuracy of compression depth estimation was performed. Results Overall, 103 subjects were enrolled in the study; 42 (40.8%) were physicians, 56 (54.4%) nurses, and 5 (4.8%) emergency medical technicians. The mean accuracy was 0.89 (standard deviation, 0.76). Among examiner determinants, only subjects’ occupation and clinical experience showed significant association with outcome (P=0.03 and P=0.08, respectively). All environmental determinants showed significant association with the outcome (all P<0.001). Multivariate analysis showed that accuracy rate was significantly associated with occupation, camera position, and compression depth. Conclusions The accuracy rate of chest compression depth estimation was 0.89 and was significantly related with examiner’s occupation, camera view position, and compression depth.

  3. Classification, change-detection and accuracy assessment: Toward fuller automation

    NASA Astrophysics Data System (ADS)

    Podger, Nancy E.

    This research aims to automate methods for conducting change detection studies using remotely sensed images. Five major objectives were tested on two study sites, one encompassing Madison, Wisconsin, and the other Fort Hood, Texas. (Objective 1) Enhance accuracy assessments by estimating standard errors using bootstrap analysis. Bootstrap estimates of the standard errors were found to be comparable to parametric statistical estimates. Also, results show that bootstrapping can be used to evaluate the consistency of a classification process. (Objective 2) Automate the guided clustering classifier. This research shows that the guided clustering classification process can be automated while maintaining highly accurate results. Three different evaluation methods were used. (Evaluation 1) Appraised the consistency of 25 classifications produced from the automated system. The classifications differed from one another by only two to four percent. (Evaluation 2) Compared accuracies produced by the automated system to classification accuracies generated following a manual guided clustering protocol. Results: The automated system produced higher overall accuracies in 50 percent of the tests and was comparable for all but one of the remaining tests. (Evaluation 3) Assessed the time and effort required to produce accurate classifications. Results: The automated system produced classifications in less time and with less effort than the manual 'protocol' method. (Objective 3) Built a flexible, interactive software tool to aid in producing binary change masks. (Objective 4) Reduced by automation the amount of training data needed to classify the second image of a two-time-period change detection project. Locations of the training sites in 'unchanged' areas employed to classify the first image were used to identify sites where spectral information was automatically extracted from the second image. Results: The automatically generated training data produces classification accuracies

  4. 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.

  5. 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.

  6. Speed and accuracy of visual image discrimination by rats.

    PubMed

    Reinagel, Pamela

    2013-01-01

    The trade-off between speed and accuracy of sensory discrimination has most often been studied using sensory stimuli that evolve over time, such as random dot motion discrimination tasks. We previously reported that when rats perform motion discrimination, correct trials have longer reaction times than errors, accuracy increases with reaction time, and reaction time increases with stimulus ambiguity. In such experiments, new sensory information is continually presented, which could partly explain interactions between reaction time and accuracy. The present study shows that a changing physical stimulus is not essential to those findings. Freely behaving rats were trained to discriminate between two static visual images in a self-paced, two-alternative forced-choice reaction time task. Each trial was initiated by the rat, and the two images were presented simultaneously and persisted until the rat responded, with no time limit. Reaction times were longer in correct trials than in error trials, and accuracy increased with reaction time, comparable to results previously reported for rats performing motion discrimination. In the motion task, coherence has been used to vary discrimination difficulty. Here morphs between the previously learned images were used to parametrically vary the image similarity. In randomly interleaved trials, rats took more time on average to respond in trials in which they had to discriminate more similar stimuli. For both the motion and image tasks, the dependence of reaction time on ambiguity is weak, as if rats prioritized speed over accuracy. Therefore we asked whether rats can change the priority of speed and accuracy adaptively in response to a change in reward contingencies. For two rats, the penalty delay was increased from 2 to 6 s. When the penalty was longer, reaction times increased, and accuracy improved. This demonstrates that rats can flexibly adjust their behavioral strategy in response to the cost of errors.

  7. 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.

  8. Changes in limb striking pattern: effects of speed and accuracy.

    PubMed

    Southard, D

    1989-12-01

    This study investigated the changes in an arm striking pattern as a result of practice and the effects of speed and accuracy requirements on such changes. The task was to strike a baseball-size foam ball from a batting tee adjusted to the height of each subject's iliac crest. Ten righthanded subjects, initially displaying an inefficient striking pattern, volunteered for this study. All subjects performed the task according to the following conditions: (1) speed, (2) accuracy, and (3) speed and accuracy. Each subject completed 10 trials in each condition (randomly ordered) for five consecutive days. A high-speed camera (64 fps) was used to photograph subjects' striking patterns for each condition over the 5-day period. Analysis of variance of joint angles at arm reversal and contact and velocity of hand relative to the glenohumeral axis at contact revealed that subjects initially constrained limb segments to act in a unitary fashion; then, with practice, a more efficient pattern was developed. The requirement of speed was found to enhance a change in limb configuration, whereas the requirement of accuracy, and subsequent reduction in speed, impeded the development of a more efficient striking pattern. Analysis of radial error revealed no differences in accuracies to the target by either condition or day of practice. A graphic analysis of segmental angular momentum versus relative time showed that joint angle changes allowed subjects to transfer angular momentum and thereby increase the velocity of the hand at contact. PMID:2489862

  9. Changes in limb striking pattern: effects of speed and accuracy.

    PubMed

    Southard, D

    1989-12-01

    This study investigated the changes in an arm striking pattern as a result of practice and the effects of speed and accuracy requirements on such changes. The task was to strike a baseball-size foam ball from a batting tee adjusted to the height of each subject's iliac crest. Ten righthanded subjects, initially displaying an inefficient striking pattern, volunteered for this study. All subjects performed the task according to the following conditions: (1) speed, (2) accuracy, and (3) speed and accuracy. Each subject completed 10 trials in each condition (randomly ordered) for five consecutive days. A high-speed camera (64 fps) was used to photograph subjects' striking patterns for each condition over the 5-day period. Analysis of variance of joint angles at arm reversal and contact and velocity of hand relative to the glenohumeral axis at contact revealed that subjects initially constrained limb segments to act in a unitary fashion; then, with practice, a more efficient pattern was developed. The requirement of speed was found to enhance a change in limb configuration, whereas the requirement of accuracy, and subsequent reduction in speed, impeded the development of a more efficient striking pattern. Analysis of radial error revealed no differences in accuracies to the target by either condition or day of practice. A graphic analysis of segmental angular momentum versus relative time showed that joint angle changes allowed subjects to transfer angular momentum and thereby increase the velocity of the hand at contact.

  10. Diagnostic Accuracy of Procalcitonin in Bacterial Meningitis Versus Nonbacterial Meningitis

    PubMed Central

    Wei, Ting-Ting; Hu, Zhi-De; Qin, Bao-Dong; Ma, Ning; Tang, Qing-Qin; Wang, Li-Li; Zhou, Lin; Zhong, Ren-Qian

    2016-01-01

    Abstract Several studies have investigated the diagnostic accuracy of procalcitonin (PCT) levels in blood or cerebrospinal fluid (CSF) in bacterial meningitis (BM), but the results were heterogeneous. The aim of the present study was to ascertain the diagnostic accuracy of PCT as a marker for BM detection. A systematic search of the EMBASE, Scopus, Web of Science, and PubMed databases was performed to identify studies published before December 7, 2015 investigating the diagnostic accuracy of PCT for BM. The quality of the eligible studies was assessed using the revised Quality Assessment for Studies of Diagnostic Accuracy method. The overall diagnostic accuracy of PCT detection in CSF or blood was pooled using the bivariate model. Twenty-two studies involving 2058 subjects were included in this systematic review and meta-analysis. The overall specificities and sensitivities were 0.86 and 0.80 for CSF PCT, and 0.97 and 0.95 for blood PCT, respectively. Areas under the summary receiver operating characteristic curves were 0.90 and 0.98 for CSF PCT and blood PCT, respectively. The major limitation of this systematic review and meta-analysis was the small number of studies included and the heterogeneous diagnostic thresholds adopted by eligible studies. Our meta-analysis shows that PCT is a useful biomarker for BM diagnosis. PMID:26986140

  11. Knowledge discovery by accuracy maximization.

    PubMed

    Cacciatore, Stefano; Luchinat, Claudio; Tenori, Leonardo

    2014-04-01

    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.

  12. 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

  13. Taking in a Show.

    PubMed

    Boden, Timothy W

    2016-01-01

    Many medical practices have cut back on education and staff development expenses, especially those costs associated with conventions and conferences. But there are hard-to-value returns on your investment in these live events--beyond the obvious benefits of acquired knowledge and skills. Major vendors still exhibit their services and wares at many events, and the exhibit hall is a treasure-house of information and resources for the savvy physician or administrator. Make and stick to a purposeful plan to exploit the trade show. You can compare products, gain new insights and ideas, and even negotiate better deals with representatives anxious to realize returns on their exhibition investments. PMID:27249887

  14. Taking in a Show.

    PubMed

    Boden, Timothy W

    2016-01-01

    Many medical practices have cut back on education and staff development expenses, especially those costs associated with conventions and conferences. But there are hard-to-value returns on your investment in these live events--beyond the obvious benefits of acquired knowledge and skills. Major vendors still exhibit their services and wares at many events, and the exhibit hall is a treasure-house of information and resources for the savvy physician or administrator. Make and stick to a purposeful plan to exploit the trade show. You can compare products, gain new insights and ideas, and even negotiate better deals with representatives anxious to realize returns on their exhibition investments.

  15. Obesity in show dogs.

    PubMed

    Corbee, R J

    2013-10-01

    Obesity is an important disease with a growing incidence. Because obesity is related to several other diseases, and decreases life span, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain breeds is often suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, we investigated 1379 dogs of 128 different breeds by determining their body condition score (BCS). Overall, 18.6% of the show dogs had a BCS >5, and 1.1% of the show dogs had a BCS>7. There were significant differences between breeds, which could be correlated to the breed standards. It warrants firm discussions with breeders and judges in order to come to different interpretations of the standards to prevent overweight conditions from being the standard of beauty. PMID:22882163

  16. 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.

  17. 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.

  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. PMID:23631336

  19. 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.

  20. Accuracy and precision of manual baseline determination.

    PubMed

    Jirasek, A; Schulze, G; Yu, M M L; Blades, M W; Turner, R F B

    2004-12-01

    Vibrational spectra often require baseline removal before further data analysis can be performed. Manual (i.e., user) baseline determination and removal is a common technique used to perform this operation. Currently, little data exists that details the accuracy and precision that can be expected with manual baseline removal techniques. This study addresses this current lack of data. One hundred spectra of varying signal-to-noise ratio (SNR), signal-to-baseline ratio (SBR), baseline slope, and spectral congestion were constructed and baselines were subtracted by 16 volunteers who were categorized as being either experienced or inexperienced in baseline determination. In total, 285 baseline determinations were performed. The general level of accuracy and precision that can be expected for manually determined baselines from spectra of varying SNR, SBR, baseline slope, and spectral congestion is established. Furthermore, the effects of user experience on the accuracy and precision of baseline determination is estimated. The interactions between the above factors in affecting the accuracy and precision of baseline determination is highlighted. Where possible, the functional relationships between accuracy, precision, and the given spectral characteristic are detailed. The results provide users of manual baseline determination useful guidelines in establishing limits of accuracy and precision when performing manual baseline determination, as well as highlighting conditions that confound the accuracy and precision of manual baseline determination.

  1. High-accuracy EUV reflectometer

    NASA Astrophysics Data System (ADS)

    Hinze, U.; Fokoua, M.; Chichkov, B.

    2007-03-01

    Developers and users of EUV-optics need precise tools for the characterization of their products. Often a measurement accuracy of 0.1% or better is desired to detect and study slow-acting aging effect or degradation by organic contaminants. To achieve a measurement accuracy of 0.1% an EUV-source is required which provides an excellent long-time stability, namely power stability, spatial stability and spectral stability. Naturally, it should be free of debris. An EUV-source particularly suitable for this task is an advanced electron-based EUV-tube. This EUV source provides an output of up to 300 μW at 13.5 nm. Reflectometers benefit from the excellent long-time stability of this tool. We design and set up different reflectometers using EUV-tubes for the precise characterisation of EUV-optics, such as debris samples, filters, multilayer mirrors, grazing incidence optics, collectors and masks. Reflectivity measurements from grazing incidence to near normal incidence as well as transmission studies were realised at a precision of down to 0.1%. The reflectometers are computer-controlled and allow varying and scanning all important parameters online. The concepts of a sample reflectometer is discussed and results are presented. The devices can be purchased from the Laser Zentrum Hannover e.V.

  2. 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

  3. Positional Accuracy of Gps Satellite Almanac

    NASA Astrophysics Data System (ADS)

    Ma, Lihua; Zhou, Shangli

    2014-12-01

    How to accelerate signal acquisition and shorten starting time are key problems in the Global Positioning System (GPS). GPS satellite almanac plays an important role in signal reception period. Almanac accuracy directly affects the speed of GPS signal acquisition, the start time of the receiver, and even the system performance to some extent. Combined with precise ephemeris products released by the International GNSS Service (IGS), the authors analyse GPS satellite almanac from the first day to the third day in the 1805th GPS week (from August 11 to 13, 2014 in the Gregorian calendar). The results show that mean of position errors in three-dimensional coordinate system varies from about 1 kilometer to 3 kilometers, which can satisfy the needs of common users.

  4. 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.

  5. 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.

  6. Improved localization accuracy in magnetic source imaging using a 3-D laser scanner.

    PubMed

    Bardouille, Timothy; Krishnamurthy, Santosh V; Hajra, Sujoy Ghosh; D'Arcy, Ryan C N

    2012-12-01

    Brain source localization accuracy in magnetoencephalography (MEG) requires accuracy in both digitizing anatomical landmarks and coregistering to anatomical magnetic resonance images (MRI). We compared the source localization accuracy and MEG-MRI coregistration accuracy of two head digitization systems-a laser scanner and the current standard electromagnetic digitization system (Polhemus)-using a calibrated phantom and human data. When compared using the calibrated phantom, surface and source localization accuracy for data acquired with the laser scanner improved over the Polhemus by 141% and 132%, respectively. Laser scan digitization reduced MEG source localization error by 1.38 mm on average. In human participants, a laser scan of the face generated a 1000-fold more points per unit time than the Polhemus head digitization. An automated surface-matching algorithm improved the accuracy of MEG-MRI coregistration over the equivalent manual procedure. Simulations showed that the laser scan coverage could be reduced to an area around the eyes only while maintaining coregistration accuracy, suggesting that acquisition time can be substantially reduced. Our results show that the laser scanner can both reduce setup time and improve localization accuracy, in comparison to the Polhemus digitization system.

  7. 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.

  8. 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. PMID:27595130

  9. Study on the accuracy factors of large-scale photogrammetry system

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Dong, Mingli; Lu, Naiguang

    2011-05-01

    In photogrammetry system, the Base-Distance Ratio, the Image Scale, and the Image Standard Error, which construct the network strength of the system, are the main accuracy factors. In this paper, the normal and convergent network configurations of the photogrammetry are studied and the Network Strength, which presents the strength and accuracy of the camera station network, is expressed with the accuracy factors mentioned above. In order to verify the validation of this expression, the large-scale 3D reference field is designed and used to test the effects of these accuracy factors. The experimental results show that the relationship between the accuracy and the factors is consistent with the expression. These conclusions will guide the photogrammetric work to reduce the system errors.

  10. Study on the accuracy factors of large-scale photogrammetry system

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Dong, Mingli; Lu, Naiguang

    2010-12-01

    In photogrammetry system, the Base-Distance Ratio, the Image Scale, and the Image Standard Error, which construct the network strength of the system, are the main accuracy factors. In this paper, the normal and convergent network configurations of the photogrammetry are studied and the Network Strength, which presents the strength and accuracy of the camera station network, is expressed with the accuracy factors mentioned above. In order to verify the validation of this expression, the large-scale 3D reference field is designed and used to test the effects of these accuracy factors. The experimental results show that the relationship between the accuracy and the factors is consistent with the expression. These conclusions will guide the photogrammetric work to reduce the system errors.

  11. 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.

  12. Landsat classification accuracy assessment procedures

    USGS Publications Warehouse

    Mead, R. R.; Szajgin, John

    1982-01-01

    A working conference was held in Sioux Falls, South Dakota, 12-14 November, 1980 dealing with Landsat classification Accuracy Assessment Procedures. Thirteen formal presentations were made on three general topics: (1) sampling procedures, (2) statistical analysis techniques, and (3) examples of projects which included accuracy assessment and the associated costs, logistical problems, and value of the accuracy data to the remote sensing specialist and the resource manager. Nearly twenty conference attendees participated in two discussion sessions addressing various issues associated with accuracy assessment. This paper presents an account of the accomplishments of the conference.

  13. Accuracy Study of a 2-Component Point Doppler Velocimeter (PDV)

    NASA Technical Reports Server (NTRS)

    Kuhlman, John; Naylor, Steve; James, Kelly; Ramanath, Senthil

    1997-01-01

    A two-component Point Doppler Velocimeter (PDV) which has recently been developed is described, and a series of velocity measurements which have been obtained to quantify the accuracy of the PDV system are summarized. This PDV system uses molecular iodine vapor cells as frequency discriminating filters to determine the Doppler shift of laser light which is scattered off of seed particles in a flow. The majority of results which have been obtained to date are for the mean velocity of a rotating wheel, although preliminary data are described for fully-developed turbulent pipe flow. Accuracy of the present wheel velocity data is approximately +/- 1 % of full scale, while linearity of a single channel is on the order of +/- 0.5 % (i.e., +/- 0.6 m/sec and +/- 0.3 m/sec, out of 57 m/sec, respectively). The observed linearity of these results is on the order of the accuracy to which the speed of the rotating wheel has been set for individual data readings. The absolute accuracy of the rotating wheel data is shown to be consistent with the level of repeatability of the cell calibrations. The preliminary turbulent pipe flow data show consistent turbulence intensity values, and mean axial velocity profiles generally agree with pitot probe data. However, there is at present an offset error in the radial velocity which is on the order of 5-10 % of the mean axial velocity.

  14. 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

  15. Accuracy of discrimination, rate of responding, and resistance to change.

    PubMed Central

    Nevin, John A; Milo, Jessica; Odum, Amy L; Shahan, Timothy A

    2003-01-01

    Pigeons were trained on multiple schedules in which responding on a center key produced matching-to-sample trials according to the same variable-interval 30-s schedules in both components. Matching trials consisted of a vertical or tilted line sample on the center key followed by vertical and tilted comparisons on the side keys. Correct responses to comparison stimuli were reinforced with probability .80 in the rich component and .20 in the lean component. Baseline response rates and matching accuracies generally were higher in the rich component, consistent with previous research. When performance was disrupted by prefeeding, response-independent food during intercomponent intervals, intrusion of a delay between sample and comparison stimuli, or extinction, both response rates and matching accuracies generally decreased. Proportions of baseline response rate were greater in the rich component for all disrupters except delay, which had relatively small and inconsistent effects on response rate. By contrast, delay had large and consistent effects on matching accuracy, and proportions of baseline matching accuracy were greater in the rich component for all four disrupters. The dissociation of response rate and accuracy with delay reflects the localized impact of delay on matching performance. The similarity of the data for response rate and accuracy with prefeeding, response-independent food, and extinction shows that matching performance, like response rate, is more resistant to change in a rich than in a lean component. This result extends resistance to change analyses from the frequency of response emission to the degree of stimulus control, and suggests that the strength of discriminating, like the strength of responding, is positively related to rate of reinforcement. PMID:12908760

  16. What Do Blood Tests Show?

    MedlinePlus

    ... shows the ranges for blood glucose levels after 8 to 12 hours of fasting (not eating). It shows the normal range and the abnormal ranges that are a sign of prediabetes or diabetes. Plasma Glucose Results (mg/dL)* Diagnosis 70 to 99 ...

  17. 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).

  18. 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…

  19. Accuracy and precision of silicon based impression media for quantitative areal texture analysis.

    PubMed

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

    2015-05-20

    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.

  20. 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

  1. 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…

  2. Wavelength Calibration Accuracy for the STIS CCD and MAMA Modes

    NASA Astrophysics Data System (ADS)

    Pascucci, Ilaria; Hodge, Phil; Proffitt, Charles R.; Ayres, T.

    2011-03-01

    Two calibration programs were carried out to determine the accuracy of the wavelength solutions for the most used STIS CCD and MAMA modes after Servicing Mission 4. We report here on the analysis of this dataset and show that the STIS wavelength solution has not changed after SM4. We also show that a typical accuracy for the absolute wavelength zero-points is 0.1 pixels while the relative wavelength accuracy is 0.2 pixels.

  3. Phase space correlation to improve detection accuracy.

    PubMed

    Carroll, T L; Rachford, F J

    2009-09-01

    The standard method used for detecting signals in radar or sonar is cross correlation. The accuracy of the detection with cross correlation is limited by the bandwidth of the signals. We show that by calculating the cross correlation based on points that are nearby in phase space rather than points that are simultaneous in time, the detection accuracy is improved. The phase space correlation technique works for some standard radar signals, but it is especially well suited to chaotic signals because trajectories that are adjacent in phase space move apart from each other at an exponential rate.

  4. Halo abundance matching: accuracy and conditions for numerical convergence

    NASA Astrophysics Data System (ADS)

    Klypin, Anatoly; Prada, Francisco; Yepes, Gustavo; Heß, Steffen; Gottlöber, Stefan

    2015-03-01

    Accurate predictions of the abundance and clustering of dark matter haloes play a key role in testing the standard cosmological model. Here, we investigate the accuracy of one of the leading methods of connecting the simulated dark matter haloes with observed galaxies- the halo abundance matching (HAM) technique. We show how to choose the optimal values of the mass and force resolution in large volume N-body simulations so that they provide accurate estimates for correlation functions and circular velocities for haloes and their subhaloes - crucial ingredients of the HAM method. At the 10 per cent accuracy, results converge for ˜50 particles for haloes and ˜150 particles for progenitors of subhaloes. In order to achieve this level of accuracy a number of conditions should be satisfied. The force resolution for the smallest resolved (sub)haloes should be in the range (0.1-0.3)rs, where rs is the scale radius of (sub)haloes. The number of particles for progenitors of subhaloes should be ˜150. We also demonstrate that the two-body scattering plays a minor role for the accuracy of N-body simulations thanks to the relatively small number of crossing-times of dark matter in haloes, and the limited force resolution of cosmological simulations.

  5. 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.

  6. Improve accuracy for automatic acetabulum segmentation in CT images.

    PubMed

    Liu, Hao; Zhao, Jianning; Dai, Ning; Qian, Hongbo; Tang, Yuehong

    2014-01-01

    Separation of the femur head and acetabulum is one of main difficulties in the diseased hip joint due to deformed shapes and extreme narrowness of the joint space. To improve the segmentation accuracy is the key point of existing automatic or semi-automatic segmentation methods. In this paper, we propose a new method to improve the accuracy of the segmented acetabulum using surface fitting techniques, which essentially consists of three parts: (1) design a surface iterative process to obtain an optimization surface; (2) change the ellipsoid fitting to two-phase quadric surface fitting; (3) bring in a normal matching method and an optimization region method to capture edge points for the fitting quadric surface. Furthermore, this paper cited vivo CT data sets of 40 actual patients (with 79 hip joints). Test results for these clinical cases show that: (1) the average error of the quadric surface fitting method is 2.3 (mm); (2) the accuracy ratio of automatically recognized contours is larger than 89.4%; (3) the error ratio of section contours is less than 10% for acetabulums without severe malformation and less than 30% for acetabulums with severe malformation. Compared with similar methods, the accuracy of our method, which is applied in a software system, is significantly enhanced.

  7. 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.

  8. Improving ASM stepper alignment accuracy by alignment signal intensity simulation

    NASA Astrophysics Data System (ADS)

    Li, Gerald; Pushpala, Sagar M.; Bradford, Bradley; Peng, Zezhong; Gottipati, Mohan

    1993-08-01

    As photolithography technology advances into submicron regime, the requirement for alignment accuracy also becomes much tighter. The alignment accuracy is a function of the strength of the alignment signal. Therefore, a detailed alignment signal intensity simulation for 0.8 micrometers EPROM poly-1 layer on ASM stepper was done based on the process of record in the fab to reduce misalignment and improve die yield. Oxide thickness variation did not have significant impact on the alignment signal intensity. However, poly-1 thickness was the most important parameter to affect optical alignments. The real alignment intensity data versus resist thickness on production wafers was collected and it showed good agreement with the simulated results. Similar results were obtained for ONO dielectric layer at a different fab.

  9. 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.

  10. Accuracy of adaptation of thermoformed poly(methyl methacrylate).

    PubMed

    Jagger, R G; Milward, P J; Jagger, D C; Vowles, R W

    2003-04-01

    Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dental appliances such as stents, occlusal splints and baseplates for occlusal rims. The purpose of the present study was to measure the accuracy of adaptation of Perspex PMMA sheet and to determine the effect of annealing on the accuracy of the thermoformed specimens. The results of the study showed that PMMA can produce specimens that are accurately adapted to the cast. Immersion in water resulted in an increase in the space between the cast and the specimen for both thermoformed and thermoformed and annealed acrylic resin. Annealing of the thermoformed specimens had significantly less increase in space between the cast and the specimens when immersed in water over a period of 3 months.

  11. 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.

  12. [Accuracy of winter wheat identification based on multi-temporal CBERS-02 images].

    PubMed

    Qi, La; Zhao, Chun-Jiang; Li, Cun-Jun; Liu, Liang-Yun; Tan, Chang-Wei; Huang, Wen-Jiang

    2008-10-01

    Chinese-Brazil Earth Resources Satellite No. 2 (CBERS-02) has good spatial resolution and abundant spectral information, and a strong ability in detecting vegetation. Based on five CBERS-02 images in winter wheat growth season, the spectral distance between winter wheat and other ground targets was calculated, and then, winter wheat was classified from each individual image or their combinations by using supervised classification. The train and validation samples were derived from high resolution Aerial Images and SPOT5 images. The accuracies and analyses were evaluated for CBERS-02 images at early growth stages, and the results were compared to those of TM images acquired in the same phenological calendars. The results showed that temporal information was the main factor affecting the classification accuracy in winter wheat, but the characteristics of different sensors could affect the classification accuracy. The multi-temporal images could improve the classification accuracy, compared with the results derived from signal stage, with the producer accuracy of optimum periods combination improved 20.0% and user accuracy improved 7.83%. Compared with TM sensor, the classification accuracy from CBERS-02 was a little lower.

  13. Accuracy investigation of phthalate metabolite standards.

    PubMed

    Langlois, Éric; Leblanc, Alain; Simard, Yves; Thellen, Claude

    2012-05-01

    Phthalates are ubiquitous compounds whose metabolites are usually determined in urine for biomonitoring studies. Following suspect and unexplained results from our laboratory in an external quality-assessment scheme, we investigated the accuracy of all phthalate metabolite standards in our possession by comparing them with those of several suppliers. Our findings suggest that commercial phthalate metabolite certified solutions are not always accurate and that lot-to-lot discrepancies significantly affect the accuracy of the results obtained with several of these standards. These observations indicate that the reliability of the results obtained from different lots of standards is not equal, which reduces the possibility of intra-laboratory and inter-laboratory comparisons of results. However, agreements of accuracy have been observed for a majority of neat standards obtained from different suppliers, which indicates that a solution to this issue is available. Data accuracy of phthalate metabolites should be of concern for laboratories performing phthalate metabolite analysis because of the standards used. The results of our investigation are presented from the perspective that laboratories performing phthalate metabolite analysis can obtain accurate and comparable results in the future. Our findings will contribute to improving the quality of future phthalate metabolite analyses and will affect the interpretation of past results.

  14. Decreased interoceptive accuracy following social exclusion.

    PubMed

    Durlik, Caroline; Tsakiris, Manos

    2015-04-01

    The need for social affiliation is one of the most important and fundamental human needs. Unsurprisingly, humans display strong negative reactions to social exclusion. In the present study, we investigated the effect of social exclusion on interoceptive accuracy - accuracy in detecting signals arising inside the body - measured with a heartbeat perception task. We manipulated exclusion using Cyberball, a widely used paradigm of a virtual ball-tossing game, with half of the participants being included during the game and the other half of participants being ostracized during the game. Our results indicated that heartbeat perception accuracy decreased in the excluded, but not in the included, participants. We discuss these results in the context of social and physical pain overlap, as well as in relation to internally versus externally oriented attention. PMID:25701592

  15. Measures of spatio-temporal accuracy for time series land cover data

    NASA Astrophysics Data System (ADS)

    Tsutsumida, Narumasa; Comber, Alexis J.

    2015-09-01

    Remote sensing is a useful tool for monitoring changes in land cover over time. The accuracy of such time-series analyses has hitherto only been assessed using confusion matrices. The matrix allows global measures of user, producer and overall accuracies to be generated, but lacks consideration of any spatial aspects of accuracy. It is well known that land cover errors are typically spatially auto-correlated and can have a distinct spatial distribution. As yet little work has considered the temporal dimension and investigated the persistence or errors in both geographic and temporal dimensions. Spatio-temporal errors can have a profound impact on both change detection and on environmental monitoring and modelling activities using land cover data. This study investigated methods for describing the spatio-temporal characteristics of classification accuracy. Annual thematic maps were created using a random forest classification of MODIS data over the Jakarta metropolitan areas for the period of 2001-2013. A logistic geographically weighted model was used to estimate annual spatial measures of user, producer and overall accuracies. A principal component analysis was then used to extract summaries of the multi-temporal accuracy. The results showed how the spatial distribution of user and producer accuracy varied over space and time, and overall spatial variance was confirmed by the principal component analysis. The results indicated that areas of homogeneous land cover were mapped with relatively high accuracy and low variability, and areas of mixed land cover with the opposite characteristics. A multi-temporal spatial approach to accuracy is shown to provide more informative measures of accuracy, allowing map producers and users to evaluate time series thematic maps more comprehensively than a standard confusion matrix approach. The need to identify suitable properties for a temporal kernel are discussed.

  16. Accuracy of CNV Detection from GWAS Data

    PubMed Central

    Zhang, Dandan; Qian, Yudong; Akula, Nirmala; Alliey-Rodriguez, Ney; Tang, Jinsong; Gershon, Elliot S.; Liu, Chunyu

    2011-01-01

    Several computer programs are available for detecting copy number variants (CNVs) using genome-wide SNP arrays. We evaluated the performance of four CNV detection software suites—Birdsuite, Partek, HelixTree, and PennCNV-Affy—in the identification of both rare and common CNVs. Each program's performance was assessed in two ways. The first was its recovery rate, i.e., its ability to call 893 CNVs previously identified in eight HapMap samples by paired-end sequencing of whole-genome fosmid clones, and 51,440 CNVs identified by array Comparative Genome Hybridization (aCGH) followed by validation procedures, in 90 HapMap CEU samples. The second evaluation was program performance calling rare and common CNVs in the Bipolar Genome Study (BiGS) data set (1001 bipolar cases and 1033 controls, all of European ancestry) as measured by the Affymetrix SNP 6.0 array. Accuracy in calling rare CNVs was assessed by positive predictive value, based on the proportion of rare CNVs validated by quantitative real-time PCR (qPCR), while accuracy in calling common CNVs was assessed by false positive/false negative rates based on qPCR validation results from a subset of common CNVs. Birdsuite recovered the highest percentages of known HapMap CNVs containing >20 markers in two reference CNV datasets. The recovery rate increased with decreased CNV frequency. In the tested rare CNV data, Birdsuite and Partek had higher positive predictive values than the other software suites. In a test of three common CNVs in the BiGS dataset, Birdsuite's call was 98.8% consistent with qPCR quantification in one CNV region, but the other two regions showed an unacceptable degree of accuracy. We found relatively poor consistency between the two “gold standards,” the sequence data of Kidd et al., and aCGH data of Conrad et al. Algorithms for calling CNVs especially common ones need substantial improvement, and a “gold standard” for detection of CNVs remains to be established. PMID:21249187

  17. 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.

  18. New Drug Shows Mixed Results Against Early Alzheimer's

    MedlinePlus

    ... Sign Up See recent e-Newsletters Preserving Your Memory Magazine Get Your Copy Now Subscribe to our ... 3 Letter Resources Articles Brochure Download Preserving Your Memory Magazine e-Newsletter Resource Locator Videos Charity Navigator ...

  19. 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.

  20. Accuracy Assessment of the Integration of GNSS and a MEMS IMU in a Terrestrial Platform

    PubMed Central

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

    2014-01-01

    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. PMID:25375757

  1. Asymptotic accuracy of two-class discrimination

    SciTech Connect

    Ho, T.K.; Baird, H.S.

    1994-12-31

    Poor quality-e.g. sparse or unrepresentative-training data is widely suspected to be one cause of disappointing accuracy of isolated-character classification in modern OCR machines. We conjecture that, for many trainable classification techniques, it is in fact the dominant factor affecting accuracy. To test this, we have carried out a study of the asymptotic accuracy of three dissimilar classifiers on a difficult two-character recognition problem. We state this problem precisely in terms of high-quality prototype images and an explicit model of the distribution of image defects. So stated, the problem can be represented as a stochastic source of an indefinitely long sequence of simulated images labeled with ground truth. Using this sequence, we were able to train all three classifiers to high and statistically indistinguishable asymptotic accuracies (99.9%). This result suggests that the quality of training data was the dominant factor affecting accuracy. The speed of convergence during training, as well as time/space trade-offs during recognition, differed among the classifiers.

  2. Performance and accuracy benchmarks for a next generation geodynamo simulation

    NASA Astrophysics Data System (ADS)

    Matsui, H.

    2015-12-01

    A number of numerical dynamo models have successfully represented basic characteristics of the geomagnetic field in the last twenty years. However, parameters in the current dynamo model are far from realistic for the Earth's core. To approach a realistic parameters for the Earth's core in geodynmo simulations, extremely large spatial resolutions are required to resolve convective turbulence and small-scale magnetic fields. To assess the next generation dynamo models on a massively parallel computer, we performed performance and accuracy benchmarks from 15 dynamo codes which employ a diverse range of discretization (spectral, finite difference, finite element, and hybrid methods) and parallelization methods. In the performance benchmark, we compare elapsed time and parallelization capability on the TACC Stampede platform, using up to 16384 processor cores. In the accuracy benchmark, we compare required resolutions to obtain less than 1% error from the suggested solutions. The results of the performance benchmark show that codes using 2-D or 3-D parallelization models have a capability to run with 16384 processor cores. The elapsed time for Calypso and Rayleigh, two parallelized codes that use the spectral method, scales with a smaller exponent than the ideal scaling. The elapsed time of SFEMaNS, which uses finite element and Fourier transform, has the smallest growth of the elapsed time with the resolution and parallelization. However, the accuracy benchmark results show that SFEMaNS require three times more degrees of freedoms in each direction compared with a spherical harmonics expansion. Consequently, SFEMaNS needs more than 200 times of elapsed time for the Calypso and Rayleigh with 10000 cores to obtain the same accuracy. These benchmark results indicate that the spectral method with 2-D or 3-D domain decomposition is the most promising methodology for advancing numerical dynamo simulations in the immediate future.

  3. 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.

  4. Social class, contextualism, and empathic accuracy.

    PubMed

    Kraus, Michael W; Côté, Stéphane; Keltner, Dacher

    2010-11-01

    Recent research suggests that lower-class individuals favor explanations of personal and political outcomes that are oriented to features of the external environment. We extended this work by testing the hypothesis that, as a result, individuals of a lower social class are more empathically accurate in judging the emotions of other people. In three studies, lower-class individuals (compared with upper-class individuals) received higher scores on a test of empathic accuracy (Study 1), judged the emotions of an interaction partner more accurately (Study 2), and made more accurate inferences about emotion from static images of muscle movements in the eyes (Study 3). Moreover, the association between social class and empathic accuracy was explained by the tendency for lower-class individuals to explain social events in terms of features of the external environment. The implications of class-based patterns in empathic accuracy for well-being and relationship outcomes are discussed. PMID:20974714

  5. Metrical Patterns of Words and Production Accuracy.

    ERIC Educational Resources Information Center

    Schwartz, Richard G.; Goffman, Lisa

    1995-01-01

    This study examined the influence of metrical patterns (syllable stress and serial position) of words on the production accuracy of 20 children (ages 22 months to 28 months). Among results were that one-fourth of the initial unstressed syllables were omitted and that consonant omissions, though few, tended to occur in the initial position.…

  6. Accuracy of Information Processing under Focused Attention.

    ERIC Educational Resources Information Center

    Bastick, Tony

    This paper reports the results of an experiment on the accuracy of information processing during attention focused arousal under two conditions: single estimation and double estimation. The attention of 187 college students was focused by a task requiring high level competition for a monetary prize ($10) under severely limited time conditions. The…

  7. Accuracy of polyp localization at colonoscopy

    PubMed Central

    O’Connor, Sam A.; Hewett, David G.; Watson, Marcus O.; Kendall, Bradley J.; Hourigan, Luke F.; Holtmann, Gerald

    2016-01-01

    Background and study aims: Accurate documentation of lesion localization at the time of colonoscopic polypectomy is important for future surveillance, management of complications such as delayed bleeding, and for guiding surgical resection. We aimed to assess the accuracy of endoscopic localization of polyps during colonoscopy and examine variables that may influence this accuracy. Patients and methods: We conducted a prospective observational study in consecutive patients presenting for elective, outpatient colonoscopy. All procedures were performed by Australian certified colonoscopists. The endoscopic location of each polyp was reported by the colonoscopist at the time of resection and prospectively recorded. Magnetic endoscope imaging was used to determine polyp location, and colonoscopists were blinded to this image. Three experienced colonoscopists, blinded to the endoscopist’s assessment of polyp location, independently scored the magnetic endoscope images to obtain a reference standard for polyp location (Cronbach alpha 0.98). The accuracy of colonoscopist polyp localization using this reference standard was assessed, and colonoscopist, procedural and patient variables affecting accuracy were evaluated. Results: A total of 155 patients were enrolled and 282 polyps were resected in 95 patients by 14 colonoscopists. The overall accuracy of polyp localization was 85 % (95 % confidence interval, CI; 60 – 96 %). Accuracy varied significantly (P < 0.001) by colonic segment: caecum 100 %, ascending 77 % (CI;65 – 90), transverse 84 % (CI;75 – 92), descending 56 % (CI;32 – 81), sigmoid 88 % (CI;79 – 97), rectum 96 % (CI;90 – 101). There were significant differences in accuracy between colonoscopists (P < 0.001), and colonoscopist experience was a significant independent predictor of accuracy (OR 3.5, P = 0.028) after adjustment for patient and procedural variables. Conclusions: Accuracy of

  8. On the accuracy of glacier outlines derived from satellite data

    NASA Astrophysics Data System (ADS)

    Paul, F.

    2012-04-01

    different and the same analysts. First results indicate that the accuracy of the glacier outlines (clean ice) as derived from automated techniques (TM3/TM5 band ratio) is similar to the standard deviation resulting from multiple digitizing experiments. Regions with low contrast in high-resolution imagery show a large variability in interpretation by different analysts. For an internal accuracy assessment it is recommended to digitize a couple of debris-covered glaciers several times and provide the mean of the standard deviations as the accuracy. An overlay of the digitized outlines is most helpful to identify the problematic regions.

  9. 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.

  10. 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.

  11. Evaluating the Accuracy of dem Generation Algorithms from Uav Imagery

    NASA Astrophysics Data System (ADS)

    Ruiz, J. J.; Diaz-Mas, L.; Perez, F.; Viguria, A.

    2013-08-01

    In this work we evaluated how the use of different positioning systems affects the accuracy of Digital Elevation Models (DEMs) generated from aerial imagery obtained with Unmanned Aerial Vehicles (UAVs). In this domain, state-of-the-art DEM generation algorithms suffer from typical errors obtained by GPS/INS devices in the position measurements associated with each picture obtained. The deviations from these measurements to real world positions are about meters. The experiments have been carried out using a small quadrotor in the indoor testbed at the Center for Advanced Aerospace Technologies (CATEC). This testbed houses a system that is able to track small markers mounted on the UAV and along the scenario with millimeter precision. This provides very precise position measurements, to which we can add random noise to simulate errors in different GPS receivers. The results showed that final DEM accuracy clearly depends on the positioning information.

  12. Accuracy Assessment of Digital Elevation Models Using GPS

    NASA Astrophysics Data System (ADS)

    Farah, Ashraf; Talaat, Ashraf; Farrag, Farrag A.

    2008-01-01

    A Digital Elevation Model (DEM) is a digital representation of ground surface topography or terrain with different accuracies for different application fields. DEM have been applied to a wide range of civil engineering and military planning tasks. DEM is obtained using a number of techniques such as photogrammetry, digitizing, laser scanning, radar interferometry, classical survey and GPS techniques. This paper presents an assessment study of DEM using GPS (Stop&Go) and kinematic techniques comparing with classical survey. The results show that a DEM generated from (Stop&Go) GPS technique has the highest accuracy with a RMS error of 9.70 cm. The RMS error of DEM derived by kinematic GPS is 12.00 cm.

  13. An evaluation of the diagnostic accuracy of Pathfinder.

    PubMed

    Heckerman, D E; Nathwani, B N

    1992-02-01

    We present an evaluation of the diagnostic accuracy of Pathfinder, an expert system that assists pathologists with the diagnosis of lymph node diseases. We evaluate two versions of the system using both informal and decision-theoretic metrics of performance. In one version of Pathfinder, we assume incorrectly that all observations are conditionally independent. In the other version, we use a belief network to represent accurately the probabilistic dependencies among the observations. In both versions, we make the assumption--reasonable for this domain--that diseases are mutually exclusive and exhaustive. The results of the study show that (1) it is cost effective to represent probabilistic dependencies among observations in the lymph node domain, and (2) the diagnostic accuracy of the more complex version of Pathfinder is at least as good as that of the Pathfinder expert. In addition, the study illustrates how informal and decision-theoretic metrics for performance complement one another.

  14. Solving the apparent diversity-accuracy dilemma of recommender systems

    PubMed Central

    Zhou, Tao; Kuscsik, Zoltán; Liu, Jian-Guo; Medo, Matúš; Wakeling, Joseph Rushton; Zhang, Yi-Cheng

    2010-01-01

    Recommender systems use data on past user preferences to predict possible future likes and interests. A key challenge is that while the most useful individual recommendations are to be found among diverse niche objects, the most reliably accurate results are obtained by methods that recommend objects based on user or object similarity. In this paper we introduce a new algorithm specifically to address the challenge of diversity and show how it can be used to resolve this apparent dilemma when combined in an elegant hybrid with an accuracy-focused algorithm. By tuning the hybrid appropriately we are able to obtain, without relying on any semantic or context-specific information, simultaneous gains in both accuracy and diversity of recommendations. PMID:20176968

  15. Accuracy study of the IDO scheme by Fourier analysis

    NASA Astrophysics Data System (ADS)

    Imai, Yohsuke; Aoki, Takayuki

    2006-09-01

    The numerical accuracy of the Interpolated Differential Operator (IDO) scheme is studied with Fourier analysis for the solutions of Partial Differential Equations (PDEs): advection, diffusion, and Poisson equations. The IDO scheme solves governing equations not only for physical variable but also for first-order spatial derivative. Spatial discretizations are based on Hermite interpolation functions with both of them. In the Fourier analysis for the IDO scheme, the Fourier coefficients of the physical variable and the first-order derivative are coupled by the equations derived from the governing equations. The analysis shows the IDO scheme resolves all the wavenumbers with higher accuracy than the fourth-order Finite Difference (FD) and Compact Difference (CD) schemes for advection equation. In particular, for high wavenumbers, the accuracy is superior to that of the sixth-order Combined Compact Difference (CCD) scheme. The diffusion and Poisson equations are also more accurately solved in comparison with the FD and CD schemes. These results show that the IDO scheme guarantees highly resolved solutions for all the terms of fluid flow equations.

  16. Effects of Accuracy Feedback on Fractal Characteristics of Time Estimation

    PubMed Central

    Kuznetsov, Nikita A.; Wallot, Sebastian

    2011-01-01

    The current experiment investigated the effect of visual accuracy feedback on the structure of variability of time interval estimates in the continuation tapping paradigm. Participants were asked to repeatedly estimate a 1-s interval for a prolonged period of time by tapping their index finger. In some conditions, participants received accuracy feedback after every estimate, whereas in other conditions, no feedback was given. Also, the likelihood of receiving visual feedback was manipulated by adjusting the tolerance band around the 1-s target interval so that feedback was displayed only if the temporal estimate deviated from the target interval by more than 50, 100, or 200 ms respectively. We analyzed the structure of variability of the inter-tap intervals with fractal and multifractal methods that allow for a quantification of complex long-range correlation patterns in the timing performance. Our results indicate that feedback changes the long-range correlation structure of time estimates: Increased amounts of feedback lead to a decrease in fractal long-range correlations, as well to a decrease in the magnitude of local fluctuations in the performance. The multifractal characteristics of the time estimates were not impacted by the presence of accuracy feedback. Nevertheless, most of the data sets show significant multifractal signatures. We interpret these findings as showing that feedback acts to constrain and possibly reorganize timing performance. Implications for mechanistic and complex systems-based theories of timing behavior are discussed. PMID:22046149

  17. Measuring the accuracy of agro-environmental indicators.

    PubMed

    Makowski, David; Tichit, Muriel; Guichard, Laurence; Van Keulen, Herman; Beaudoin, Nicolas

    2009-05-01

    Numerous agro-environmental indicators have been developed by agronomists and ecologists during the last 20 years to assess the environmental impact of farmers' practices, and to monitor effects of agro-environmental policies. The objectives of this paper were (i) to measure the accuracy of a wide range of agro-environmental indicators from experimental data and (ii) to discuss the value of different information typically used by these indicators, i.e. information on farmers' practices, and on plant and soil characteristics. Four series of indicators were considered in this paper: indicators of habitat quality for grassland bird species, indicators of risk of disease in oilseed rape crops, indicators of risk of pollution by nitrogen fertilizer, and indicators of weed infestation. Several datasets were used to measure their accuracy in cultivated plots and in grasslands. The sensitivity, specificity, and probability of correctly ranking plots were estimated for each indicator. Our results showed that the indicators had widely varying levels of accuracy. Some show very poor performance and had no discriminatory ability. Other indicators were informative and performed better than random decisions. Among the tested indicators, the best ones were those using information on plant characteristics such as grass height, fraction of diseased flowers, or crop yield. The statistical method applied in this paper could support researchers, farm advisers, and decision makers in comparing various indicators. PMID:19128870

  18. Accuracy-precision trade-off in visual orientation constancy.

    PubMed

    De Vrijer, M; Medendorp, W P; Van Gisbergen, J A M

    2009-02-09

    Using the subjective visual vertical task (SVV), previous investigations on the maintenance of visual orientation constancy during lateral tilt have found two opposite bias effects in different tilt ranges. The SVV typically shows accurate performance near upright but severe undercompensation at tilts beyond 60 deg (A-effect), frequently with slight overcompensation responses (E-effect) in between. Here we investigate whether a Bayesian spatial-perception model can account for this error pattern. The model interprets A- and E-effects as the drawback of a computational strategy, geared at maintaining visual stability with optimal precision at small tilt angles. In this study, we test whether these systematic errors can be seen as the consequence of a precision-accuracy trade-off when combining a veridical but noisy signal about eye orientation in space with the visual signal. To do so, we used a psychometric approach to assess both precision and accuracy of the SVV in eight subjects laterally tilted at 9 different tilt angles (-120 degrees to 120 degrees). Results show that SVV accuracy and precision worsened with tilt angle, according to a pattern that could be fitted quite adequately by the Bayesian model. We conclude that spatial vision essentially follows the rules of Bayes' optimal observer theory.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    Craft, D. William

    1992-02-01

    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.

  1. 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.

  2. High accuracy fine-pointing system - Breadboard performances and results

    NASA Astrophysics Data System (ADS)

    Fazilleau, Y.; Moreau, B.; Betermier, J. M.; Boutemy, J. C.

    A fine pointing system designed according to the requirements of the Semiconductor Laser Intersatellite Link Experiment 1989 (SILEX 1989) is described, with particular attention given to the synthesis of the final breadboarding. The study includes all the pointing functions where the pointing, acquisition, and tracking (PAT) functions are associated with different FOVs. The laboratory model consists of a complete pointing system with two CCD sensors for detection, two general-scanning single-axis actuators, and the overall control electronics. Each major PAT function of the laboratory model was separately tested, giving all the major impacts for the future PAT applications concerning mechanical margins, optical aberrations, sensor linearity, and servoloop communications.

  3. 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

  4. 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.

  5. Effect of training on exposure judgment accuracy of industrial hygienists.

    PubMed

    Vadali, Monika; Ramachandran, Gurumurthy; Mulhausen, John R; Banerjee, Sudipto

    2012-01-01

    Results are presented from a study that investigated the effect of data interpretation training on exposure judgment accuracy of industrial hygienists across several companies in different industry sectors. Participating companies provided monitoring information on specific exposure tasks. Forty-nine hygienists from six companies participated in the study, and 22 industrial tasks were evaluated. The number of monitoring data points for individual tasks varied between 5 and 24. After reviewing all available basic characterization information for the job, task, and chemical, hygienists were asked to provide their judgment on the probability of the 95th percentile of the underlying exposure distribution being located in one of four exposure categories relative to the occupational exposure limit as outlined in the AIHA exposure assessment strategy. Ninety-three qualitative judgments (i.e., without reviewing monitoring data) and 2142 quantitative judgments (i.e., those made after reviewing monitoring data) were obtained. Data interpretation training, with simple rules of thumb for estimating 95th percentiles, was provided to all hygienists. A data interpretation test was administered before and after training. All exposure task judgments were collected before and after training. Data interpretation test accuracy for the hygienists increased from 48% to 67% after training (p < 0.001) and a significant underestimation bias was removed. Hygienist quantitative task judgment accuracy improved from 46% to 69% (p < 0.001) post-training. Accuracy results showed good improvement in industrial hygienists' quantitative judgments as a result of training. Hence, the use of statistical tools is promoted to improve judgments based on monitoring data and provide feedback and calibration to improve qualitative judgments. It may be worthwhile to develop standard training programs to improve exposure judgments.

  6. 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.

  7. 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

  8. Surface accuracy analysis of large deployable antennas

    NASA Astrophysics Data System (ADS)

    Tang, Yaqiong; Li, Tuanjie; Wang, Zuowei; Deng, Hanqing

    2014-11-01

    This paper performs an analysis to the systematic surface figure error influenced by three factors including errors of faceted paraboloids, fabrication imperfection and random thermal strains in orbit. Firstly, the computational formulas for root-mean-square surface deviations caused by these factors are presented respectively. The stochastic finite element method is applied to derive the computational formulas of fabrication imperfection and random thermal strains, by which the sensitivity of surface accuracy to component imperfection can be revealed. Then the Monte Carlo simulation method is introduced to obtain the surface figure by sampling test on random errors. Finally, the analytical method is applied to the research on the surface figure error of AstroMesh deployable reflector. The results show that the deviations between the root-mean-square surface errors calculated by the proposed formulas with less consuming time and those by the Monte Carlo simulation method are less than 2%, which indicates that the proposed method is efficient and receivable enough to analyze systematic surface figure error of a large deployable antenna. Moreover, further investigations on the relationship between surface RMS deviation and the antenna parameters including aperture and the number of subdivisions are presented in the end.

  9. The accuracy of a voice vote

    PubMed Central

    Titze, Ingo R.; Palaparthi, Anil

    2014-01-01

    The accuracy of a voice vote was addressed by systematically varying group size, individual voter loudness, and words that are typically used to express agreement or disagreement. Five judges rated the loudness of two competing groups in A-B comparison tasks. Acoustic analysis was performed to determine the sound energy level of each word uttered by each group. Results showed that individual voter differences in energy level can grossly alter group loudness and bias the vote. Unless some control is imposed on the sound level of individual voters, it is difficult to establish even a two-thirds majority, much less a simple majority. There is no symmetry in the bias created by unequal sound production of individuals. Soft voices do not bias the group loudness much, but loud voices do. The phonetic balance of the two words chosen (e.g., “yea” and “nay” as opposed to “aye” and “no”) seems to be less of an issue. PMID:24437776

  10. Assessment of optical localizer accuracy for computer aided surgery systems.

    PubMed

    Elfring, Robert; de la Fuente, Matías; Radermacher, Klaus

    2010-01-01

    The technology for localization of surgical tools with respect to the patient's reference coordinate system in three to six degrees of freedom is one of the key components in computer aided surgery. Several tracking methods are available, of which optical tracking is the most widespread in clinical use. Optical tracking technology has proven to be a reliable method for intra-operative position and orientation acquisition in many clinical applications; however, the accuracy of such localizers is still a topic of discussion. In this paper, the accuracy of three optical localizer systems, the NDI Polaris P4, the NDI Polaris Spectra (in active and passive mode) and the Stryker Navigation System II camera, is assessed and compared critically. Static tests revealed that only the Polaris P4 shows significant warm-up behavior, with a significant shift of accuracy being observed within 42 minutes of being switched on. Furthermore, the intrinsic localizer accuracy was determined for single markers as well as for tools using a volumetric measurement protocol on a coordinate measurement machine. To determine the relative distance error within the measurement volume, the Length Measurement Error (LME) was determined at 35 test lengths. As accuracy depends strongly on the marker configuration employed, the error to be expected in typical clinical setups was estimated in a simulation for different tool configurations. The two active localizer systems, the Stryker Navigation System II camera and the Polaris Spectra (active mode), showed the best results, with trueness values (mean +/- standard deviation) of 0.058 +/- 0.033 mm and 0.089 +/- 0.061 mm, respectively. The Polaris Spectra (passive mode) showed a trueness of 0.170 +/- 0.090 mm, and the Polaris P4 showed the lowest trueness at 0.272 +/- 0.394 mm with a higher number of outliers than for the other cameras. The simulation of the different tool configurations in a typical clinical setup revealed that the tracking error can

  11. 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.

  12. Proper installation ensures turbine meter accuracy

    SciTech Connect

    Peace, D.W.

    1995-07-01

    Turbine meters are widely used for natural gas measurement and provide high accuracy over large ranges of operation. However, as with many other types of flowmeters, consideration must be given to the design of the turbine meter and the installation piping practice to ensure high-accuracy measurement. National and international standards include guidelines for proper turbine meter installation piping and methods for evaluating the effects of flow disturbances on the design of those meters. Swirl or non-uniform velocity profiles, such as jetting, at the turbine meter inlet can cause undesirable accuracy performance changes. Sources of these types of flow disturbances can be from the installation piping configuration, an upstream regulator, a throttled valve, or a partial blockage upstream of the meter. Test results on the effects of swirl and jetting on different types of meter designs and sizes emphasize the need to consider good engineering design for turbine meters, including integral flow conditioning vanes and adequate installation piping practices for high accuracy measurement.

  13. Data Accuracy in Citation Studies.

    ERIC Educational Resources Information Center

    Boyce, Bert R.; Banning, Carolyn Sue

    1979-01-01

    Four hundred eighty-seven citations of the 1976 issues of the Journal of the American Society for Information Science and the Personnel and Guidance Journal were checked for accuracy: total error was 13.6 percent and 10.7 percent, respectively. Error categories included incorrect author name, article/book title, journal title; wrong entry; and…

  14. Indicators of Late Emerging Reading-Accuracy Difficulties in Australian Schools

    ERIC Educational Resources Information Center

    Galletly, Susan A.; Knight, Bruce Allen; Dekkers, John; Galletly, Tracey A.

    2009-01-01

    Late-emerging reading-accuracy difficulties are those found present in older students not showing reading-accuracy difficulties when tested in earlier years (Leach, Scarborough and Rescorla, 2003). This paper discusses the constructs of reading-accuracy and late-emerging reading-accuracy difficulties. It then discusses data from a cross-sectional…

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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 (...

  20. Plan Showing Cross Bracing Under Upper Stringers, Typical Section Showing ...

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

    Plan Showing Cross Bracing Under Upper Stringers, Typical Section Showing End Framing, Plan Showing Cross Bracing Under Lower Stringers, End Elevation - Covered Bridge, Spanning Contoocook River, Hopkinton, Merrimack County, NH

  1. Speed versus accuracy in collective decision making.

    PubMed

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

    2003-12-01

    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.

  2. 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.

  3. 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

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

    PubMed

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

    2014-11-21

    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.

  5. 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.

  6. 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.

  7. Accuracy of stellar parameters determined from multicolor photometry

    NASA Astrophysics Data System (ADS)

    Sichevskij, S. G.; Mironov, A. V.; Malkov, O. Yu.

    2014-04-01

    The development and application of new methods for intelligent analysis and extraction of information from digital sky surveys carried out in various spectral domains have now become a popular field in astrophysical research and, in particular, in stellar studies. Modern large-scale photometric surveys provide data for 105-106 relatively faint objects, and the lack of spectroscopic data can be compensated by the cross identification of the objects followed by an analysis of all catalogued photometric data. In this paper we investigate the possibility of determining the effective temperature, surface gravity, total extinction, and the total-to-selective extinction ratio based on the photometry provided in the 2MASS, SDSS, and GALEX surveys, and estimate the accuracy of the inferred parameters. We use a library of theoretical spectra to compute the magnitudes of stars in the photometric bands of the above surveys for various sets of input parameters. We compare the differences between the computed magnitudes with the errors of the corresponding surveys. We find that stellar parameters can be computed over a sizable domain of the parameter space. We estimate the accuracy of the resulting parameters. We show that the presence of far-ultraviolet data in the available set of observed magnitudes increases the accuracy of the inferred parameters.

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

    PubMed

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

    2014-11-21

    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. PMID:25332308

  9. Do saccharide doped PAGAT dosimeters increase accuracy?

    NASA Astrophysics Data System (ADS)

    Berndt, B.; Skyt, P. S.; Holloway, L.; Hill, R.; Sankar, A.; De Deene, Y.

    2015-01-01

    To improve the dosimetric accuracy of normoxic polyacrylamide gelatin (PAGAT) gel dosimeters, the addition of saccharides (glucose and sucrose) has been suggested. An increase in R2-response sensitivity upon irradiation will result in smaller uncertainties in the derived dose if all other uncertainties are conserved. However, temperature variations during the magnetic resonance scanning of polymer gels result in one of the highest contributions to dosimetric uncertainties. The purpose of this project was to study the dose sensitivity against the temperature sensitivity. The overall dose uncertainty of PAGAT gel dosimeters with different concentrations of saccharides (0, 10 and 20%) was investigated. For high concentrations of glucose or sucrose, a clear improvement of the dose sensitivity was observed. For doses up to 6 Gy, the overall dose uncertainty was reduced up to 0.3 Gy for all saccharide loaded gels compared to PAGAT gel. Higher concentrations of glucose and sucrose deteriorate the accuracy of PAGAT dosimeters for doses above 9 Gy.

  10. 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.

  11. Keyboarding Accuracy for a Student with Physical Disabilities: A Synergistic Approach

    ERIC Educational Resources Information Center

    Obringer, S. John; Coffey, Kenneth; McFadden, Gary; Etheridge, Jill; Pounder, Rebecca

    2007-01-01

    The purpose of this study was to examine a synergistic application of three different technologies to improve the keyboarding accuracy of an individual with significant motor disorders. Three keyboarding technologies were layered to measure the power of each technology independently and collectively. The results show a significant increase in…

  12. 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…

  13. Improved Motor-Timing: Effects of Synchronized Metro-Nome Training on Golf Shot Accuracy

    PubMed Central

    Sommer, Marius; Rönnqvist, Louise

    2009-01-01

    This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. Twenty-six experienced male golfers participated (mean age 27 years; mean golf handicap 12.6) in this study. Pre- and post-test investigations of golf shots made by three different clubs were conducted by use of a golf simulator. The golfers were randomized into two groups: a SMT group and a Control group. After the pre-test, the golfers in the SMT group completed a 4-week SMT program designed to improve their motor timing, the golfers in the Control group were merely training their golf-swings during the same time period. No differences between the two groups were found from the pre-test outcomes, either for motor timing scores or for golf shot accuracy. However, the post-test results after the 4-weeks SMT showed evident motor timing improvements. Additionally, significant improvements for golf shot accuracy were found for the SMT group and with less variability in their performance. No such improvements were found for the golfers in the Control group. As with previous studies that used a SMT program, this study’s results provide further evidence that motor timing can be improved by SMT and that such timing improvement also improves golf accuracy. Key points This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. A randomized control group design was used. The 4 week SMT intervention showed significant improvements in motor timing, golf shot accuracy, and lead to less variability. We conclude that this study’s results provide further evidence that motor timing can be improved by SMT training and that such timing improvement also improves golf accuracy. PMID:24149608

  14. 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

  15. 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.

  16. 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/. PMID:20385580

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

    2014-01-01

    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

  3. 3D combinational curves for accuracy and performance analysis of positive biometrics identification

    NASA Astrophysics Data System (ADS)

    Du, Yingzi; Chang, Chein-I.

    2008-06-01

    The receiver operating characteristic (ROC) curve has been widely used as an evaluation criterion to measure the accuracy of biometrics system. Unfortunately, such an ROC curve provides no indication of the optimum threshold and cost function. In this paper, two kinds of 3D combinational curves are proposed: the 3D combinational accuracy curve and the 3D combinational performance curve. The 3D combinational accuracy curve gives a balanced view of the relationships among FAR (false alarm rate), FRR (false rejection rate), threshold t, and Cost. Six 2D curves can be derived from the 3D combinational accuracy curve: the conventional 2D ROC curve, 2D curve of (FRR, t), 2D curve of (FAR, t), 2D curve of (FRR, Cost), 2D curve of (FAR, Cost), and 2D curve of ( t, Cost). The 3D combinational performance curve can be derived from the 3D combinational accuracy curve which can give a balanced view among Security, Convenience, threshold t, and Cost. The advantages of using the proposed 3D combinational curves are demonstrated by iris recognition systems where the experimental results show that the proposed 3D combinational curves can provide more comprehensive information of the system accuracy and performance.

  4. Determining the Accuracy of Aerodynamic Model Parameters Estimated from Flight Test Data

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.; Klein, Vladislav

    1995-01-01

    An important part of building mathematical models based on measured data is calculating the accuracy associated with statistical estimates of the model parameters. Indeed, without some idea of this accuracy, the parameter estimates themselves have limited value. In this work, an expression for computing quantitatively correct parameter accuracy measures for maximum likelihood parameter estimates with colored residuals is developed and validated. This result is important because experience in analyzing flight test data reveals that the output residuals from maximum likelihood estimation are almost always colored. The calculations involved can be appended to conventional maximum likelihood estimation algorithms. Monte Carlo simulation runs were used to show that parameter accuracy measures from the new technique accurately reflect the quality of the parameter estimates from maximum likelihood estimation without the need for correction factors or frequency domain analysis of the output residuals. The technique was applied to flight test data from repeated maneuvers flown on the F-18 High Alpha Research Vehicle (HARV). As in the simulated cases, parameter accuracy measures from the new technique were in agreement with the scatter in the parameter estimates from repeated maneuvers, while conventional parameter accuracy measures were optimistic.

  5. Accuracy of NHANES periodontal examination protocols.

    PubMed

    Eke, P I; Thornton-Evans, G O; Wei, L; Borgnakke, W S; Dye, B A

    2010-11-01

    This study evaluates the accuracy of periodontitis prevalence determined by the National Health and Nutrition Examination Survey (NHANES) partial-mouth periodontal examination protocols. True periodontitis prevalence was determined in a new convenience sample of 454 adults ≥ 35 years old, by a full-mouth "gold standard" periodontal examination. This actual prevalence was compared with prevalence resulting from analysis of the data according to the protocols of NHANES III and NHANES 2001-2004, respectively. Both NHANES protocols substantially underestimated the prevalence of periodontitis by 50% or more, depending on the periodontitis case definition used, and thus performed below threshold levels for moderate-to-high levels of validity for surveillance. Adding measurements from lingual or interproximal sites to the NHANES 2001-2004 protocol did not improve the accuracy sufficiently to reach acceptable sensitivity thresholds. These findings suggest that NHANES protocols produce high levels of misclassification of periodontitis cases and thus have low validity for surveillance and research.

  6. Piezoresistive position microsensors with ppm-accuracy

    NASA Astrophysics Data System (ADS)

    Stavrov, Vladimir; Shulev, Assen; Stavreva, Galina; Todorov, Vencislav

    2015-05-01

    In this article, the relation between position accuracy and the number of simultaneously measured values, such as coordinates, has been analyzed. Based on this, a conceptual layout of MEMS devices (microsensors) for multidimensional position monitoring comprising a single anchored and a single actuated part has been developed. Both parts are connected with a plurality of micromechanical flexures, and each flexure includes position detecting cantilevers. Microsensors having detecting cantilevers oriented in X and Y direction have been designed and prototyped. Experimentally measured results at characterization of 1D, 2D and 3D position microsensors are reported as well. Exploiting different flexure layouts, a travel range between 50μm and 1.8mm and sensors' sensitivity in the range between 30μV/μm and 5mV/μm@ 1V DC supply voltage have been demonstrated. A method for accurate calculation of all three Cartesian coordinates, based on measurement of at least three microsensors' signals has also been described. The analyses of experimental results prove the capability of position monitoring with ppm-(part per million) accuracy. The technology for fabrication of MEMS devices with sidewall embedded piezoresistors removes restrictions in strong improvement of their usability for position sensing with a high accuracy. The present study is, also a part of a common strategy for developing a novel MEMS-based platform for simultaneous accurate measurement of various physical values when they are transduced to a change of position.

  7. 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.

  8. Laboratory reporting accuracy of polymerase chain reaction testing for avian polyomavirus.

    PubMed

    Fitzgerald, Brenna; Olsen, Geoff; Speer, Brian

    2013-03-01

    Polymerase chain reaction (PCR) assays are available for detection of birds infected with avian polyomavirus (APV). Several laboratories offer this diagnostic assay in the United States, but little information is available regarding assay sensitivity, specificity, and accuracy. In this study, known APV-positive and APV-negative samples (each n = 10, 5 undiluted and 5 diluted) were sent to 5 commercial laboratories. A significant difference in reporting accuracy was found among laboratories, most notably for dilute APV-positive samples. Two out of 5 laboratories provided 100% accurate results, 1 had an accuracy of 90%, and 2 reported 80% and 75% accuracy, respectively. The accuracies of the last 2 laboratories were negatively affected by test sensitivities of 60% and 50%, respectively. These findings show that although accurate results were reported by most laboratories, both false-positive and false-negative results were reported by at least 3 laboratories, and false-negative results reported for dilute APV-positive samples predominated. These study findings illustrate a need for veterinary diagnostic laboratories to institute improved voluntary quality control measures.

  9. 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.

  10. Interpersonal Deception: V. Accuracy in Deception Detection.

    ERIC Educational Resources Information Center

    Burgoon, Judee K.; And Others

    1994-01-01

    Investigates the influence of several factors on accuracy in detecting truth and deceit. Found that accuracy was much higher on truth than deception, novices were more accurate than experts, accuracy depended on type of deception and whether suspicion was present or absent, suspicion impaired accuracy for experts, and questions strategy…

  11. Assessing the accuracy of different simplified frictional rolling contact algorithms

    NASA Astrophysics Data System (ADS)

    Vollebregt, E. A. H.; Iwnicki, S. D.; Xie, G.; Shackleton, P.

    2012-01-01

    This paper presents an approach for assessing the accuracy of different frictional rolling contact theories. The main characteristic of the approach is that it takes a statistically oriented view. This yields a better insight into the behaviour of the methods in diverse circumstances (varying contact patch ellipticities, mixed longitudinal, lateral and spin creepages) than is obtained when only a small number of (basic) circumstances are used in the comparison. The range of contact parameters that occur for realistic vehicles and tracks are assessed using simulations with the Vampire vehicle system dynamics (VSD) package. This shows that larger values for the spin creepage occur rather frequently. Based on this, our approach is applied to typical cases for which railway VSD packages are used. The results show that particularly the USETAB approach but also FASTSIM give considerably better results than the linear theory, Vermeulen-Johnson, Shen-Hedrick-Elkins and Polach methods, when compared with the 'complete theory' of the CONTACT program.

  12. 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

  13. 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.

  14. 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).

  15. 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

  16. Determining gas-meter accuracy

    SciTech Connect

    Valenti, M.

    1997-03-01

    This article describes how engineers at the Metering Research Facility are helping natural-gas companies improve pipeline efficiency by evaluating and refining the instruments used for measuring and setting prices. Accurate metering of natural gas is more important than ever as deregulation subjects pipeline companies to competition. To help improve that accuracy, the Gas Research Institute (GRI) in Chicago has sponsored the Metering Research Facility (MRF) at the Southwest Research Institute (SWRI) in San Antonio, Tex. The MRF evaluates and improves the performance of orifice, turbine, diaphragm, and ultrasonic meters as well as the gas-sampling methods that pipeline companies use to measure the flow of gas and determine its price.

  17. Accuracy and reliability of China's energy statistics

    SciTech Connect

    Sinton, Jonathan E.

    2001-09-14

    Many observers have raised doubts about the accuracy and reliability of China's energy statistics, which show an unprecedented decline in recent years, while reported economic growth has remained strong. This paper explores the internal consistency of China's energy statistics from 1990 to 2000, coverage and reporting issues, and the state of the statistical reporting system. Available information suggests that, while energy statistics were probably relatively good in the early 1990s, their quality has declined since the mid-1990s. China's energy statistics should be treated as a starting point for analysis, and explicit judgments regarding ranges of uncertainty should accompany any conclusions.

  18. 8. Detail showing concrete abutment, showing substructure of bridge, specifically ...

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

    8. Detail showing concrete abutment, showing substructure of bridge, specifically west side of arch and substructure. - Presumpscot Falls Bridge, Spanning Presumptscot River at Allen Avenue extension, 0.75 mile west of U.S. Interstate 95, Falmouth, Cumberland County, ME

  19. 28. MAP SHOWING LOCATION OF ARVFS FACILITY AS BUILT. SHOWS ...

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

    28. MAP SHOWING LOCATION OF ARVFS FACILITY AS BUILT. SHOWS LINCOLN BOULEVARD, BIG LOST RIVER, AND NAVAL REACTORS FACILITY. F.C. TORKELSON DRAWING NUMBER 842-ARVFS-101-2. DATED OCTOBER 12, 1965. INEL INDEX CODE NUMBER: 075 0101 851 151969. - Idaho National Engineering Laboratory, Advanced Reentry Vehicle Fusing System, Scoville, Butte County, ID

  20. Ground Truth Accuracy Tests of GPS Seismology

    NASA Astrophysics Data System (ADS)

    Elosegui, P.; Oberlander, D. J.; Davis, J. L.; Baena, R.; Ekstrom, G.

    2005-12-01

    As the precision of GPS determinations of site position continues to improve the detection of smaller and faster geophysical signals becomes possible. However, lack of independent measurements of these signals often precludes an assessment of the accuracy of such GPS position determinations. This may be particularly true for high-rate GPS applications. We have built an apparatus to assess the accuracy of GPS position determinations for high-rate applications, in particular the application known as "GPS seismology." The apparatus consists of a bidirectional, single-axis positioning table coupled to a digitally controlled stepping motor. The motor, in turn, is connected to a Field Programmable Gate Array (FPGA) chip that synchronously sequences through real historical earthquake profiles stored in Erasable Programmable Read Only Memory's (EPROM). A GPS antenna attached to this positioning table undergoes the simulated seismic motions of the Earth's surface while collecting high-rate GPS data. Analysis of the time-dependent position estimates can then be compared to the "ground truth," and the resultant GPS error spectrum can be measured. We have made extensive measurements with this system while inducing simulated seismic motions either in the horizontal plane or the vertical axis. A second stationary GPS antenna at a distance of several meters was simultaneously collecting high-rate (5 Hz) GPS data. We will present the calibration of this system, describe the GPS observations and data analysis, and assess the accuracy of GPS for high-rate geophysical applications and natural hazards mitigation.

  1. Pea Plants Show Risk Sensitivity.

    PubMed

    Dener, Efrat; Kacelnik, Alex; Shemesh, Hagai

    2016-07-11

    Sensitivity to variability in resources has been documented in humans, primates, birds, and social insects, but the fit between empirical results and the predictions of risk sensitivity theory (RST), which aims to explain this sensitivity in adaptive terms, is weak [1]. RST predicts that agents should switch between risk proneness and risk aversion depending on state and circumstances, especially according to the richness of the least variable option [2]. Unrealistic assumptions about agents' information processing mechanisms and poor knowledge of the extent to which variability imposes specific selection in nature are strong candidates to explain the gap between theory and data. RST's rationale also applies to plants, where it has not hitherto been tested. Given the differences between animals' and plants' information processing mechanisms, such tests should help unravel the conflicts between theory and data. Measuring root growth allocation by split-root pea plants, we show that they favor variability when mean nutrient levels are low and the opposite when they are high, supporting the most widespread RST prediction. However, the combination of non-linear effects of nitrogen availability at local and systemic levels may explain some of these effects as a consequence of mechanisms not necessarily evolved to cope with variance [3, 4]. This resembles animal examples in which properties of perception and learning cause risk sensitivity even though they are not risk adaptations [5]. PMID:27374342

  2. Developing a Weighted Measure of Speech Sound Accuracy

    PubMed Central

    Preston, Jonathan L.; Ramsdell, Heather L.; Oller, D. Kimbrough; Edwards, Mary Louise; Tobin, Stephen J.

    2010-01-01

    Purpose The purpose is to develop a system for numerically quantifying a speaker’s phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, we describe a system for differentially weighting speech sound errors based on various levels of phonetic accuracy with a Weighted Speech Sound Accuracy (WSSA) score. We then evaluate the reliability and validity of this measure. Method Phonetic transcriptions are analyzed from several samples of child speech, including preschoolers and young adolescents with and without speech sound disorders and typically developing toddlers. The new measure of phonetic accuracy is compared to existing measures, is used to discriminate typical and disordered speech production, and is evaluated to determine whether it is sensitive to changes in phonetic accuracy over time. Results Initial psychometric data indicate that WSSA scores correlate with other measures of phonetic accuracy as well as listeners’ judgments of severity of a child’s speech disorder. The measure separates children with and without speech sound disorders. WSSA scores also capture growth in phonetic accuracy in toddler’s speech over time. Conclusion Results provide preliminary support for the WSSA as a valid and reliable measure of phonetic accuracy in children’s speech. PMID:20699344

  3. 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.

  4. 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.

  5. 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. PMID:21550259

  6. Cone beam CT guidance provides superior accuracy for complex needle paths compared with CT guidance

    PubMed Central

    Braak, S J; Fütterer, J J; van Strijen, M J L; Hoogeveen, Y L; de Lange, F; Schultze Kool, L J

    2013-01-01

    Objective: To determine the accuracy of cone beam CT (CBCT) guidance and CT guidance in reaching small targets in relation to needle path complexity in a phantom. Methods: CBCT guidance combines three-dimensional CBCT imaging with fluoroscopy overlay and needle planning software to provide real-time needle guidance. The accuracy of needle positioning, quantified as deviation from a target, was assessed for inplane, angulated and double angulated needle paths. Four interventional radiologists reached four targets along the three paths using CBCT and CT guidance. Accuracies were compared between CBCT and CT for each needle path and between the three approaches within both modalities. The effect of user experience in CBCT guidance was also assessed. Results: Accuracies for CBCT were significantly better than CT for the double angulated needle path (2.2 vs 6.7 mm, p<0.001) for all radiologists. CBCT guidance showed no significant differences between the three approaches. For CT, deviations increased with increasing needle path complexity from 3.3 mm for the inplane placements to 4.4 mm (p=0.007) and 6.7 mm (p<0.001) for the angulated and double angulated CT-guided needle placements, respectively. For double angulated needle paths, experienced CBCT users showed consistently higher accuracies than trained users [1.8 mm (range 1.2–2.2) vs 3.3 mm (range 2.1–7.2) deviation from target, respectively; p=0.003]. Conclusion: In terms of accuracy, CBCT is the preferred modality, irrespective of the level of user experience, for more difficult guidance procedures requiring double angulated needle paths as in oncological interventions. Advances in knowledge: Accuracy of CBCT guidance has not been discussed before. CBCT guidance allows accurate needle placement irrespective of needle path complexity. For angulated and double-angulated needle paths, CBCT is more accurate than CT guidance. PMID:23913308

  7. Factors Governing the Accuracy of Subvisible Particle Counting Methods.

    PubMed

    Ríos Quiroz, Anacelia; Finkler, Christof; Huwyler, Joerg; Mahler, Hanns-Christian; Schmidt, Roland; Koulov, Atanas V

    2016-07-01

    A number of new techniques for subvisible particle characterization in biotechnological products have emerged in the last decade. Although the pharmaceutical community is actively using them, the current knowledge about the analytical performance of some of these tools is still inadequate to support their routine use in the development of biopharmaceuticals (especially in the case of submicron methods). With the aim of increasing this knowledge and our understanding of the most prominent techniques for subvisible particle characterization, this study reports the results of a systematic evaluation of their accuracy. Our results showed a marked overcounting effect especially for low concentrated samples and particles fragile in nature. Furthermore, we established the relative sample size distribution as the most important contributor to an instrument's performance in accuracy counting. The smaller the representation of a particle size within a solution, the more difficulty the instruments had in providing an accurate count. These findings correlate with a recent study examining the principal factors influencing the precision of the subvisible particle measurements. A more thorough understanding of the capabilities of the different particle characterization methods provided here will help guide the application of these methods and the interpretation of results in subvisible particle characterization studies.

  8. Factors Governing the Accuracy of Subvisible Particle Counting Methods.

    PubMed

    Ríos Quiroz, Anacelia; Finkler, Christof; Huwyler, Joerg; Mahler, Hanns-Christian; Schmidt, Roland; Koulov, Atanas V

    2016-07-01

    A number of new techniques for subvisible particle characterization in biotechnological products have emerged in the last decade. Although the pharmaceutical community is actively using them, the current knowledge about the analytical performance of some of these tools is still inadequate to support their routine use in the development of biopharmaceuticals (especially in the case of submicron methods). With the aim of increasing this knowledge and our understanding of the most prominent techniques for subvisible particle characterization, this study reports the results of a systematic evaluation of their accuracy. Our results showed a marked overcounting effect especially for low concentrated samples and particles fragile in nature. Furthermore, we established the relative sample size distribution as the most important contributor to an instrument's performance in accuracy counting. The smaller the representation of a particle size within a solution, the more difficulty the instruments had in providing an accurate count. These findings correlate with a recent study examining the principal factors influencing the precision of the subvisible particle measurements. A more thorough understanding of the capabilities of the different particle characterization methods provided here will help guide the application of these methods and the interpretation of results in subvisible particle characterization studies. PMID:27287519

  9. Analyses and Comparison of Accuracy of Different Genotype Imputation Methods

    PubMed Central

    Pei, Yu-Fang; Li, Jian; Zhang, Lei; Papasian, Christopher J.; Deng, Hong-Wen

    2008-01-01

    The power of genetic association analyses is often compromised by missing genotypic data which contributes to lack of significant findings, e.g., in in silico replication studies. One solution is to impute untyped SNPs from typed flanking markers, based on known linkage disequilibrium (LD) relationships. Several imputation methods are available and their usefulness in association studies has been demonstrated, but factors affecting their relative performance in accuracy have not been systematically investigated. Therefore, we investigated and compared the performance of five popular genotype imputation methods, MACH, IMPUTE, fastPHASE, PLINK and Beagle, to assess and compare the effects of factors that affect imputation accuracy rates (ARs). Our results showed that a stronger LD and a lower MAF for an untyped marker produced better ARs for all the five methods. We also observed that a greater number of haplotypes in the reference sample resulted in higher ARs for MACH, IMPUTE, PLINK and Beagle, but had little influence on the ARs for fastPHASE. In general, MACH and IMPUTE produced similar results and these two methods consistently outperformed fastPHASE, PLINK and Beagle. Our study is helpful in guiding application of imputation methods in association analyses when genotype data are missing. PMID:18958166

  10. Speed and accuracy of dyslexic versus typical word recognition: an eye-movement investigation

    PubMed Central

    Kunert, Richard; Scheepers, Christoph

    2014-01-01

    Developmental dyslexia is often characterized by a dual deficit in both word recognition accuracy and general processing speed. While previous research into dyslexic word recognition may have suffered from speed-accuracy trade-off, the present study employed a novel eye-tracking task that is less prone to such confounds. Participants (10 dyslexics and 12 controls) were asked to look at real word stimuli, and to ignore simultaneously presented non-word stimuli, while their eye-movements were recorded. Improvements in word recognition accuracy over time were modeled in terms of a continuous non-linear function. The words' rhyme consistency and the non-words' lexicality (unpronounceable, pronounceable, pseudohomophone) were manipulated within-subjects. Speed-related measures derived from the model fits confirmed generally slower processing in dyslexics, and showed a rhyme consistency effect in both dyslexics and controls. In terms of overall error rate, dyslexics (but not controls) performed less accurately on rhyme-inconsistent words, suggesting a representational deficit for such words in dyslexics. Interestingly, neither group showed a pseudohomophone effect in speed or accuracy, which might call the task-independent pervasiveness of this effect into question. The present results illustrate the importance of distinguishing between speed- vs. accuracy-related effects for our understanding of dyslexic word recognition. PMID:25346708

  11. Speed and accuracy of dyslexic versus typical word recognition: an eye-movement investigation.

    PubMed

    Kunert, Richard; Scheepers, Christoph

    2014-01-01

    Developmental dyslexia is often characterized by a dual deficit in both word recognition accuracy and general processing speed. While previous research into dyslexic word recognition may have suffered from speed-accuracy trade-off, the present study employed a novel eye-tracking task that is less prone to such confounds. Participants (10 dyslexics and 12 controls) were asked to look at real word stimuli, and to ignore simultaneously presented non-word stimuli, while their eye-movements were recorded. Improvements in word recognition accuracy over time were modeled in terms of a continuous non-linear function. The words' rhyme consistency and the non-words' lexicality (unpronounceable, pronounceable, pseudohomophone) were manipulated within-subjects. Speed-related measures derived from the model fits confirmed generally slower processing in dyslexics, and showed a rhyme consistency effect in both dyslexics and controls. In terms of overall error rate, dyslexics (but not controls) performed less accurately on rhyme-inconsistent words, suggesting a representational deficit for such words in dyslexics. Interestingly, neither group showed a pseudohomophone effect in speed or accuracy, which might call the task-independent pervasiveness of this effect into question. The present results illustrate the importance of distinguishing between speed- vs. accuracy-related effects for our understanding of dyslexic word recognition. PMID:25346708

  12. Analysis and improvement of accuracy, sensitivity, and resolution of the coherent gradient sensing method.

    PubMed

    Dong, Xuelin; Zhang, Changxing; Feng, Xue; Duan, Zhiyin

    2016-06-10

    The coherent gradient sensing (CGS) method, one kind of shear interferometry sensitive to surface slope, has been applied to full-field curvature measuring for decades. However, its accuracy, sensitivity, and resolution have not been studied clearly. In this paper, we analyze the accuracy, sensitivity, and resolution for the CGS method based on the derivation of its working principle. The results show that the sensitivity is related to the grating pitch and distance, and the accuracy and resolution are determined by the wavelength of the laser beam and the diameter of the reflected beam. The sensitivity is proportional to the ratio of grating distance to its pitch, while the accuracy will decline as this ratio increases. In addition, we demonstrate that using phase gratings as the shearing element can improve the interferogram and enhance accuracy, sensitivity, and resolution. The curvature of a spherical reflector is measured by CGS with Ronchi gratings and phase gratings under different experimental parameters to illustrate this analysis. All of the results are quite helpful for CGS applications. PMID:27409035

  13. Cochrane diagnostic test accuracy reviews.

    PubMed

    Leeflang, Mariska M G; Deeks, Jonathan J; Takwoingi, Yemisi; Macaskill, Petra

    2013-10-07

    In 1996, shortly after the founding of The Cochrane Collaboration, leading figures in test evaluation research established a Methods Group to focus on the relatively new and rapidly evolving methods for the systematic review of studies of diagnostic tests. Seven years later, the Collaboration decided it was time to develop a publication format and methodology for Diagnostic Test Accuracy (DTA) reviews, as well as the software needed to implement these reviews in The Cochrane Library. A meeting hosted by the German Cochrane Centre in 2004 brought together key methodologists in the area, many of whom became closely involved in the subsequent development of the methodological framework for DTA reviews. DTA reviews first appeared in The Cochrane Library in 2008 and are now an integral part of the work of the Collaboration.

  14. 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.

  15. 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. ...

  16. 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.

  17. Quantifying the accuracy of laboratory SIP experimental set ups

    NASA Astrophysics Data System (ADS)

    Ntarlagiannis, D.; Slater, L. D.

    2014-12-01

    Over the last decade the spectral induced polarization (SIP) method has reemerged as a promising method for subsurface investigations. The sensitivity of SIP to bulk and interfacial physicochemical properties permits a wider range of hydrogeophysical and environmental applications, including monitoring of subsurface biogeochemical transformations. Improvements in instrumentation and experimental designs, along with faster acquisition capabilities and easy access to processing routines are encouraging novel applications of the method, and support quantitative interpretation of the data acquired. Motivated by recent research that focus on small scale changes, over large frequency ranges, we performed a series of experiments to identify the accuracy of common laboratory SIP experimental set ups. We performed measurements on resistor - capacitor (RC) networks, to identify the instrumentation accuracy, and also on standard laboratory columns filled with materials of known SIP response, primarily on well characterized fluids of different conductivity. Early results show small errors in the low frequency range, attributed to electrode polarization; in higher frequencies, typically above 1000 Hz, the errors may become significant limiting the meaningful interpretation of small phase angles at these frequencies. The data will be compared with published data using comparable experimental set ups, and could be used to set realistic expectations on future SIP experiments and applications. With this work we aim at developing a best practices document that can aid the SIP user in collecting meaningful and repeatable results.

  18. 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

  19. 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.

  20. Geometrical accuracy improvement in flexible roll forming lines

    NASA Astrophysics Data System (ADS)

    Larrañaga, J.; Berner, S.; Galdos, L.; Groche, P.

    2011-01-01

    The general interest to produce profiles with variable cross section in a cost-effective way has increased in the last few years. The flexible roll forming process allows producing profiles with variable cross section lengthwise in a continuous way. Until now, only a few flexible roll forming lines were developed and built up. Apart from the flange wrinkling along the transition zone of u-profiles with variable cross section, the process limits have not been investigated and solutions for shape deviations are unknown. During the PROFOM project a flexible roll forming machine has been developed with the objective of producing high technological components for automotive body structures. In order to investigate the limits of the process, different profile geometries and steel grades including high strength steels have been applied. During the first experimental tests, several errors have been identified, as a result of the complex stress states generated during the forming process. In order to improve the accuracy of the target profiles and to meet the tolerance demands of the automotive industry, a thermo-mechanical solution has been proposed. Additional mechanical devices, supporting flexible the roll forming process, have been implemented in the roll forming line together with local heating techniques. The combination of both methods shows a significant increase of the accuracy. In the present investigation, the experimental results of the validation process are presented.

  1. 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

  2. On the Accuracy of Atmospheric Parameter Determination in BAFGK Stars

    NASA Astrophysics Data System (ADS)

    Ryabchikova, T.; Piskunov, N.; Shulyak, D.

    2015-04-01

    During the past few years, many papers determining the atmospheric parameters in FGK stars appeared in the literature where the accuracy of effective temperatures is given as 20-40 K. For main sequence stars within the 5 000-13 000 K temperature range, we have performed a comparative analysis of the parameters derived from the spectra by using the SME (Spectroscopy Made Easy) package and those found in the literature. Our sample includes standard stars Sirius, Procyon, δ Eri, and the Sun. Combining different spectral regions in the fitting procedure, we investigated an effect different atomic species have on the derived atmospheric parameters. The temperature difference may exceed 100 K depending on the spectral regions used in the SME procedure. It is shown that the atmospheric parameters derived with the SME procedure which includes wings of hydrogen lines in fitting agrees better with the results derived by the other methods and tools across a large part of the main sequence. For three stars—π Cet, 21 Peg, and Procyon—the atmospheric parameters were also derived by fitting a calculated energy distribution to the observed one. We found a substantial difference in the parameters inferred from different sets and combinations of spectrophotometric observations. An intercomparison of our results and literature data shows that the average accuracy of effective temperature determination for cool stars and for the early B-stars is 70-85 K and 170-200 K, respectively.

  3. Insensitivity of the octahedral spherical hohlraum to power imbalance, pointing accuracy, and assemblage accuracy

    SciTech Connect

    Huo, Wen Yi; Zhao, Yiqing; Zheng, Wudi; Liu, Jie; Lan, Ke

    2014-11-15

    The random radiation asymmetry in the octahedral spherical hohlraum [K. Lan et al., Phys. Plasmas 21, 0 10704 (2014)] arising from the power imbalance, pointing accuracy of laser quads, and the assemblage accuracy of capsule is investigated by using the 3-dimensional view factor model. From our study, for the spherical hohlraum, the random radiation asymmetry arising from the power imbalance of the laser quads is about half of that in the cylindrical hohlraum; the random asymmetry arising from the pointing error is about one order lower than that in the cylindrical hohlraum; and the random asymmetry arising from the assemblage error of capsule is about one third of that in the cylindrical hohlraum. Moreover, the random radiation asymmetry in the spherical hohlraum is also less than the amount in the elliptical hohlraum. The results indicate that the spherical hohlraum is more insensitive to the random variations than the cylindrical hohlraum and the elliptical hohlraum. Hence, the spherical hohlraum can relax the requirements to the power imbalance and pointing accuracy of laser facility and the assemblage accuracy of capsule.

  4. 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.

  5. 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

  6. Accuracy estimation of foamy virus genome copying

    PubMed Central

    Gärtner, Kathleen; Wiktorowicz, Tatiana; Park, Jeonghae; Mergia, Ayalew; Rethwilm, Axel; Scheller, Carsten

    2009-01-01

    Background Foamy viruses (FVs) are the most genetically stable viruses of the retrovirus family. This is in contrast to the in vitro error rate found for recombinant FV reverse transcriptase (RT). To investigate the accuracy of FV genome copying in vivo we analyzed the occurrence of mutations in HEK 293T cell culture after a single round of reverse transcription using a replication-deficient vector system. Furthermore, the frequency of FV recombination by template switching (TS) and the cross-packaging ability of different FV strains were analyzed. Results We initially sequenced 90,000 nucleotides and detected 39 mutations, corresponding to an in vivo error rate of approximately 4 × 10-4 per site per replication cycle. Surprisingly, all mutations were transitions from G to A, suggesting that APOBEC3 activity is the driving force for the majority of mutations detected in our experimental system. In line with this, we detected a late but significant APOBEC3G and 3F mRNA by quantitative PCR in the cells. We then analyzed 170,000 additional nucleotides from experiments in which we co-transfected the APOBEC3-interfering foamy viral bet gene and observed a significant 50% drop in G to A mutations, indicating that APOBEC activity indeed contributes substantially to the foamy viral replication error rate in vivo. However, even in the presence of Bet, 35 out of 37 substitutions were G to A, suggesting that residual APOBEC activity accounted for most of the observed mutations. If we subtract these APOBEC-like mutations from the total number of mutations, we calculate a maximal intrinsic in vivo error rate of 1.1 × 10-5 per site per replication. In addition to the point mutations, we detected one 49 bp deletion within the analyzed 260000 nucleotides. Analysis of the recombination frequency of FV vector genomes revealed a 27% probability for a template switching (TS) event within a 1 kilobase (kb) region. This corresponds to a 98% probability that FVs undergo at least one

  7. [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). PMID:27386623

  8. [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).

  9. Accuracy and dimensional stability of four interocclusal recording materials.

    PubMed

    Balthazar-Hart, Y; Sandrik, J L; Malone, W F; Mazur, B; Hart, T

    1981-06-01

    Four materials, zinc oxide-eugenol paste, eugenol-free-zinc oxide paste, a silicone, and polyether jaw relations registration material were studied in a controlled laboratory environment to determine their accuracy and stability in intervals over a 1-week period. The results are as follows: 1. The eugenol-free zinc-oxide paste was the only material which exhibited no statistically significant difference between the die scribes and those of the sample. 2. The setting reaction of the eugenol-free-zinc oxide paste was a saponification reaction, resulting in the production of an insoluble soap. 3. With polyether, silicone, and zinc oxide-eugenol paste, there was a statistical difference between the die and the respective samples at the immediate reading and throughout the experiment. Polyether showed the least difference, and zinc oxide-eugenol paste the greatest.

  10. Towards GPS orbit accuracy of tens of centimeters

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.

    1990-01-01

    In this paper, CASA Uno orbit results are presented utilizing data from four continents. Refinements in orbit modeling, combined with the availability of a worldwide tracking network and the dense distribution of tracking sites in North and South America, have improved orbit determination precision to about 60 cm (per component) for four of the seven GPS satellites tracked in CASA Uno. The orbit results are consistent with California baseline repeatabilities, which are at the few mm level in horizontal and length, and 1-2 cm in the vertical. Baseline comparisons with VLBI provide a measure of orbit accuracy, showing sub-cm agreement in length and 1.5 cm agreement in the horizontal.

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

    PubMed

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

    2016-07-01

    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

  12. Arches showing UV flaring activity

    NASA Technical Reports Server (NTRS)

    Fontenla, J. M.

    1988-01-01

    The UVSP data obtained in the previous maximum activity cycle show the frequent appearance of flaring events in the UV. In many cases these flaring events are characterized by at least two footpoints which show compact impulsive non-simultaneous brightenings and a fainter but clearly observed arch developes between the footpoints. These arches and footpoints are observed in line corresponding to different temperatures, as Lyman alpha, N V, and C IV, and when observed above the limb display large Doppler shifts at some stages. The size of the arches can be larger than 20 arcsec.

  13. New Criteria for Assessing the Accuracy of Blood Glucose Monitors meeting, October 28, 2011.

    PubMed

    Walsh, John; Roberts, Ruth; Vigersky, Robert A; Schwartz, Frank

    2012-03-01

    Glucose meters (GMs) are routinely used for self-monitoring of blood glucose by patients and for point-of-care glucose monitoring by health care providers in outpatient and inpatient settings. Although widely assumed to be accurate, numerous reports of inaccuracies with resulting morbidity and mortality have been noted. Insulin dosing errors based on inaccurate GMs are most critical. On October 28, 2011, the Diabetes Technology Society invited 45 diabetes technology clinicians who were attending the 2011 Diabetes Technology Meeting to participate in a closed-door meeting entitled New Criteria for Assessing the Accuracy of Blood Glucose Monitors. This report reflects the opinions of most of the attendees of that meeting. The Food and Drug Administration (FDA), the public, and several medical societies are currently in dialogue to establish a new standard for GM accuracy. This update to the FDA standard is driven by improved meter accuracy, technological advances (pumps, bolus calculators, continuous glucose monitors, and insulin pens), reports of hospital and outpatient deaths, consumer complaints about inaccuracy, and research studies showing that several approved GMs failed to meet FDA or International Organization for Standardization standards in postapproval testing. These circumstances mandate a set of new GM standards that appropriately match the GMs' analytical accuracy to the clinical accuracy required for their intended use, as well as ensuring their ongoing accuracy following approval. The attendees of the New Criteria for Assessing the Accuracy of Blood Glucose Monitors meeting proposed a graduated standard and other methods to improve GM performance, which are discussed in this meeting report.

  14. [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.

  15. Create a Polarized Light Show.

    ERIC Educational Resources Information Center

    Conrad, William H.

    1992-01-01

    Presents a lesson that introduces students to polarized light using a problem-solving approach. After illustrating the concept using a slinky and poster board with a vertical slot, students solve the problem of creating a polarized light show using Polya's problem-solving methods. (MDH)

  16. Pembrolizumab Shows Promise for NSCLC.

    PubMed

    2015-06-01

    Data from the KEYNOTE-001 trial show that pembrolizumab improves clinical outcomes for patients with advanced non-small cell lung cancer, and is well tolerated. PD-L1 expression in at least 50% of tumor cells correlated with improved efficacy.

  17. Diagnostic accuracy of preoperative clinical examination in upper limb injuries

    PubMed Central

    Dehghani, Mohammad; Shemshaki, Hamidreza; Eshaghi, Mohammad Amin; Teimouri, Mehdi

    2011-01-01

    Background: Injuries in hands and forearms may cause significant discomfort and disability. Aim: To evaluate the accuracy of preoperative clinical examination in depicting lesions caused by penetrating wounds of hands or forearms. Setting and Design: This prospective study was conducted from August 2006 to September 2009 at Kashani University Hospital, Isfahan University of Medical Sciences, Iran. Materials and Methods: Two hundred and fifty patients with clean penetrating injury to the hand/forearm were enrolled in this study. After patient's data registration, a careful clinical examination and routine exploration without expansion of wound were done by an orthopedic resident. Each tendon was tested at each joint level. Nerves were evaluated with a two-point discrimination test, and arteries were tested with palpable pulses. Surgical exploration was done by a single hand surgeon in operation room. Accuracy of clinical examination was compared to surgical examination. Results: During the study period, 180 (72%) males and 70 (28%) females with mean age of 28±4 years participated. The preoperative examination showed a predominance of the volar zone IV injuries followed by volar zone II, III, thumb zone II, volar zone V and thumb zone III. Despite the enough accuracy of preoperative examinations in dorsal side injuries of hands and forearms (error rate = 8.3%), the preoperative examinations significantly underestimated the amount of damage to soft tissues on the volar side of hands and forearms (error rate = 14%). Conclusions: The precise surgical evaluations should be considered in patients with penetrating injury to the hand or forearm, especially in those with volar side injuries. PMID:22090738

  18. Test-retest reliability for hitting accuracy tennis test.

    PubMed

    Strecker, Estevam; Foster, Ernest B; Pascoe, David D

    2011-12-01

    Strecker, E, Foster, EB, and Pascoe, DD. Test-retest reliability for hitting accuracy tennis test. J Strength Cond Res 25(12): 3501-3505, 2011-The purpose of this investigation was to assess a test-retest reliability of the hitting accuracy tennis test (HATT). Twelve National Collegiate Athletic Association (NCAA) division I tennis players (4 men and 8 women) volunteered to participate in this investigation. Skill tests consisted of 15 consecutive ground strokes in all 4 directions (forehand [FH] and backhand [BH]; crosscourt and up the line) with not >1 minute between directions. The court was divided into 12 areas, and each area was assigned a value according to a grid system based on offensive, defensive, and neutral shots ranging from 1 point to 6 points. Total score, unforced errors, and shot index (total number of shots that landed on optimal performance areas 5 and 6 minus total number of unforced errors) were used for statistical analysis. The order of shot direction was randomized between participants and trials. The analysis of variance with repeated measures (p value ≤ 0.05) of this investigation showed no statistical difference between trials on any of the measurements. The results also suggest that division I level tennis players have the ability to hit accurately specific targets on a tennis court using either FH or BH with minimal daily variation. Therefore, we conclude that the HATT for trained tennis athletes is a simple, reliable, and accurate assessment tool to measure tennis skill performance based on accuracy. The HATT is also an easy, inexpensive training device that coaches can use to monitor players development.

  19. Precise Orbital Solutions for KEPLER Eclipsing Binaries of W UMa Type Showing Total Eclipses

    NASA Astrophysics Data System (ADS)

    Şenavcı, H. V.; Doǧruel, M. B.; Nelson, R. H.; Yılmaz, M.; Selam, S. O.

    2016-09-01

    We aim to discover the accuracy of photometric mass ratios (q ph) determined for eclipsing binary stars, in the case of the system having at least one `flat bottom' as a minimum profile, as well as the accuracy of data used in that sense. Within this context, we present the results of two-dimensional grid search (q - i) for some W UMa-type eclipsing binaries showing total eclipses, based on the high precision photometric data provided by the KEPLER Mission. The radial velocity data obtained for KIC10618253 in this study, enables us to compare both q ph and the corresponding spectroscopic mass ratio (q sp) values. The results indicate that the high precision photometric data for overcontact eclipsing binaries showing total eclipses allow us to obtain the photometric mass ratios as accurate as the spectroscopic values.

  20. Randomly dividing homologous samples leads to overinflated accuracies for emotion recognition.

    PubMed

    Liu, Shuang; Zhang, Di; Xu, Minpeng; Qi, Hongzhi; He, Feng; Zhao, Xin; Zhou, Peng; Zhang, Lixin; Ming, Dong

    2015-04-01

    There are numerous studies measuring the brain emotional status by analyzing EEGs under the emotional stimuli that have occurred. However, they often randomly divide the homologous samples into training and testing groups, known as randomly dividing homologous samples (RDHS), despite considering the impact of the non-emotional information among them, which would inflate the recognition accuracy. This work proposed a modified method, the integrating homologous samples (IHS), where the homologous samples were either used to build a classifier, or to be tested. The results showed that the classification accuracy was much lower for the IHS than for the RDHS. Furthermore, a positive correlation was found between the accuracy and the overlapping rate of the homologous samples. These findings implied that the overinflated accuracy did exist in those previous studies where the RDHS method was employed for emotion recognition. Moreover, this study performed a feature selection for the IHS condition based on the support vector machine-recursive feature elimination, after which the average accuracies were greatly improved to 85.71% and 77.18% in the picture-induced and video-induced tasks, respectively.

  1. 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.

  2. 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.

  3. Accuracy of laser beam center and width calculations.

    PubMed

    Mana, G; Massa, E; Rovera, A

    2001-03-20

    The application of lasers in high-precision measurements and the demand for accuracy make the plane-wave model of laser beams unsatisfactory. Measurements of the variance of the transverse components of the photon impulse are essential for wavelength determination. Accuracy evaluation of the relevant calculations is thus an integral part of the assessment of the wavelength of stabilized-laser radiation. We present a propagation-of-error analysis on variance calculations when digitized intensity profiles are obtained by means of silicon video cameras. Image clipping criteria are obtained that maximize the accuracy of the computed result.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Accuracy enhanced thermal face recognition

    NASA Astrophysics Data System (ADS)

    Lin, Chun-Fu; Lin, Sheng-Fuu

    2013-11-01

    Human face recognition has been generally researched for the last three decades. Face recognition with thermal image has begun to attract significant attention gradually since illumination of environment would not affect the recognition performance. However, the recognition performance of traditional thermal face recognizer is still insufficient in practical application. This study presents a novel thermal face recognizer employing not only thermal features but also critical facial geometric features which would not be influenced by hair style to improve the recognition performance. A three-layer back-propagation feed-forward neural network is applied as the classifier. Traditional thermal face recognizers only use the indirect information of the topography of blood vessels like thermogram as features. To overcome this limitation, the proposed thermal face recognizer can use not only the indirect information but also the direct information of the topography of blood vessels which is unique for every human. Moreover, the recognition performance of the proposed thermal features would not decrease even if the hair of frontal bone varies, the eye blinks or the nose breathes. Experimental results show that the proposed features are significantly more effective than traditional thermal features and the recognition performance of thermal face recognizer is improved.

  9. 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.

  10. 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.

  11. 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.

  12. The Accuracy of Broselow Tape Weight Estimate among Pediatric Population

    PubMed Central

    AlGarni, Abdullaziz; AlGamdi, Fasial; Jawish, Mona; Wani, Tariq Ahmad

    2016-01-01

    Objective. To determine the accuracy of the Broselow Tape (BT) versions 2007 and 2011 in estimating weight among pediatric population. Methods. A cross-sectional study was conducted at King Fahad Medical City and six schools across Riyadh province on 1–143-month-old children. BT 2007 and 2011 estimated weights were recorded. Both tapes via the child's height produce an estimated weight, which was compared with the actual weight. Results. A total of 3537 children were recruited. The height (cm) of the subjects was 97.7 ± 24.1 and the actual weight (kg) was 16.07 ± 8.9, whereas the estimated weight determined by BT 2007 was 15.87 ± 7.56 and by BT 2011 was 16.38 ± 7.95. Across all the five age groups, correlation between actual weight and BT 2007 ranged between 0.702 and 0.788, while correlation between actual weight and BT 2011 ranged between 0.698 and 0.788. Correlation between BT 2007 and BT 2011 across all the five age groups ranged from 0.979 to 0.989. Accuracy of both the tape versions was adversely affected when age was >95 months and body weight was >26 kilograms. Conclusions. Our study showed that BT 2007 and 2011 provided accurate estimation of the body weight based on measured body height. However, 2011 version provided more precise estimate for weight. PMID:27668258

  13. Paediatric intraocular lens implants: accuracy of lens power calculations.

    PubMed

    O'Gallagher, M K; Lagan, M A; Mulholland, C P; Parker, M; McGinnity, G; McLoone, E M

    2016-09-01

    PurposeThis study aims to evaluate the accuracy of lens prediction formulae on a paediatric population.MethodsA retrospective case-note review was undertaken of patients under 8 years old who underwent cataract surgery with primary lens implantation in a regional referral centre for paediatric ophthalmology, excluding those whose procedure was secondary to trauma. Biometric and refractive data were analysed for 43 eyes, including prediction errors (PE). Statistical measures used included mean absolute error (MAE), median absolute error (MedAE), Student's t-test and Lin's correlation coefficient.ResultsThe mean PE using the SRK-II formula was +0.96 D (range -2.47D to +2.41 D, SD 1.33 D, MAE 1.38 D, MedAE 1.55, n=15). The mean PE was smaller using SRK/T (-0.18 D, range -3.25 D to +3.95 D, SD 1.70 D, MAE 1.30 D, MedAE 1.24, n=27). We performed an analysis of the biometry data using four different formula (Hoffer Q, Holladay 1, SRK-II and SRK/T). Hoffer Q showed a smaller MedAE than other formulae but also a myopic bias.ConclusionOur clinical data suggest SRK/T was more accurate in predicting post-operative refraction in this cohort of paediatric patients undergoing cataract surgery. Hoffer Q may have improved accuracy further.

  14. Solving the accuracy-diversity dilemma via directed random walks.

    PubMed

    Liu, Jian-Guo; Shi, Kerui; Guo, Qiang

    2012-01-01

    Random walks have been successfully used to measure user or object similarities in collaborative filtering (CF) recommender systems, which is of high accuracy but low diversity. A key challenge of a CF system is that the reliably accurate results are obtained with the help of peers' recommendation, but the most useful individual recommendations are hard to be found among diverse niche objects. In this paper we investigate the direction effect of the random walk on user similarity measurements and find that the user similarity, calculated by directed random walks, is reverse to the initial node's degree. Since the ratio of small-degree users to large-degree users is very large in real data sets, the large-degree users' selections are recommended extensively by traditional CF algorithms. By tuning the user similarity direction from neighbors to the target user, we introduce a new algorithm specifically to address the challenge of diversity of CF and show how it can be used to solve the accuracy-diversity dilemma. Without relying on any context-specific information, we are able to obtain accurate and diverse recommendations, which outperforms the state-of-the-art CF methods. This work suggests that the random-walk direction is an important factor to improve the personalized recommendation performance.

  15. Solving the accuracy-diversity dilemma via directed random walks

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Guo; Shi, Kerui; Guo, Qiang

    2012-01-01

    Random walks have been successfully used to measure user or object similarities in collaborative filtering (CF) recommender systems, which is of high accuracy but low diversity. A key challenge of a CF system is that the reliably accurate results are obtained with the help of peers' recommendation, but the most useful individual recommendations are hard to be found among diverse niche objects. In this paper we investigate the direction effect of the random walk on user similarity measurements and find that the user similarity, calculated by directed random walks, is reverse to the initial node's degree. Since the ratio of small-degree users to large-degree users is very large in real data sets, the large-degree users' selections are recommended extensively by traditional CF algorithms. By tuning the user similarity direction from neighbors to the target user, we introduce a new algorithm specifically to address the challenge of diversity of CF and show how it can be used to solve the accuracy-diversity dilemma. Without relying on any context-specific information, we are able to obtain accurate and diverse recommendations, which outperforms the state-of-the-art CF methods. This work suggests that the random-walk direction is an important factor to improve the personalized recommendation performance.

  16. The Accuracy of Broselow Tape Weight Estimate among Pediatric Population

    PubMed Central

    AlGarni, Abdullaziz; AlGamdi, Fasial; Jawish, Mona; Wani, Tariq Ahmad

    2016-01-01

    Objective. To determine the accuracy of the Broselow Tape (BT) versions 2007 and 2011 in estimating weight among pediatric population. Methods. A cross-sectional study was conducted at King Fahad Medical City and six schools across Riyadh province on 1–143-month-old children. BT 2007 and 2011 estimated weights were recorded. Both tapes via the child's height produce an estimated weight, which was compared with the actual weight. Results. A total of 3537 children were recruited. The height (cm) of the subjects was 97.7 ± 24.1 and the actual weight (kg) was 16.07 ± 8.9, whereas the estimated weight determined by BT 2007 was 15.87 ± 7.56 and by BT 2011 was 16.38 ± 7.95. Across all the five age groups, correlation between actual weight and BT 2007 ranged between 0.702 and 0.788, while correlation between actual weight and BT 2011 ranged between 0.698 and 0.788. Correlation between BT 2007 and BT 2011 across all the five age groups ranged from 0.979 to 0.989. Accuracy of both the tape versions was adversely affected when age was >95 months and body weight was >26 kilograms. Conclusions. Our study showed that BT 2007 and 2011 provided accurate estimation of the body weight based on measured body height. However, 2011 version provided more precise estimate for weight.

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

    PubMed

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

    2013-01-01

    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. PMID:26589009

  18. 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.

  19. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

    LRO definitive and predictive accuracy requirements were easily met in the nominal mission orbit, using the LP150Q lunar gravity model. center dot Accuracy of the LP150Q model is poorer in the extended mission elliptical orbit. center dot Later lunar gravity models, in particular GSFC-GRAIL-270, improve OD accuracy in the extended mission. center dot Implementation of a constrained plane when the orbit is within 45 degrees of the Earth-Moon line improves cross-track accuracy. center dot Prediction accuracy is still challenged during full-Sun periods due to coarse spacecraft area modeling - Implementation of a multi-plate area model with definitive attitude input can eliminate prediction violations. - The FDF is evaluating using analytic and predicted attitude modeling to improve full-Sun prediction accuracy. center dot Comparison of FDF ephemeris file to high-precision ephemeris files provides gross confirmation that overlap compares properly assess orbit accuracy.

  20. 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

    2015-08-01

    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.

  1. The red planet shows off

    NASA Astrophysics Data System (ADS)

    Beish, J. D.; Parker, D. C.; Hernandez, C. E.

    1989-01-01

    Results from observations of Mars between November 1987 and September 1988 are reviewed. The observations were part of a program to provide continuous global coverage of Mars in the period surrounding its opposition on September 28, 1988. Observations of Martian clouds, dust storms, the planet's south pole, and the Martian surface are discussed.

  2. 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

  3. 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.

  4. 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.

  5. "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.

  6. ShowMe3D

    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 themore » 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.« less

  7. 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.

  8. 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…

  9. 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.

  10. Accuracy validation for MRI-guided robotic prostate biopsy

    NASA Astrophysics Data System (ADS)

    Xu, Helen; Lasso, Andras; Vikal, Siddharth; Guion, Peter; Krieger, Axel; Kaushal, Aradhana; Whitcomb, Louis L.; Fichtinger, Gabor

    2010-02-01

    We report a quantitative evaluation of the clinical accuracy of a MRI-guided robotic prostate biopsy system that has been in use for over five years at the U.S. National Cancer Institute. A two-step rigid volume registration using mutual information between the pre and post needle insertion images was performed. Contour overlays of the prostate before and after registration were used to validate the registration. A total of 20 biopsies from 5 patients were evaluated. The maximum registration error was 2 mm. The mean biopsy target displacement, needle placement error, and biopsy error was 5.4 mm, 2.2 mm, and 5.1 mm respectively. The results show that the pre-planned biopsy target did dislocate during the procedure and therefore causing biopsy errors.

  11. 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.

  12. Accuracy in determining voice source parameters

    NASA Astrophysics Data System (ADS)

    Leonov, A. S.; Sorokin, V. N.

    2014-11-01

    The paper addresses the accuracy of an approximate solution to the inverse problem of retrieving the shape of a voice source from a speech signal for a known signal-to-noise ratio (SNR). It is shown that if the source is found as a function of time with the A.N. Tikhonov regularization method, the accuracy of the found approximation is worse than the accuracy of speech signal recording by an order of magnitude. In contrast, adequate parameterization of the source ensures approximate solution accuracy comparable with the accuracy of the problem data. A corresponding algorithm is considered. On the basis of linear (in terms of data errors) estimates of approximate parametric solution accuracy, parametric models with the best accuracy can be chosen. This comparison has been carried out for the known voice source models, i.e., model [17] and the LF model [18]. The advantages of the latter are shown. Thus, for SNR = 40 dB, the relative accuracy of an approximate solution found with this algorithm is about 1% for the LF model and about 2% for model [17] as compared to an accuracy of 7-8% in the regularization method. The role of accuracy estimates found in speaker identification problems is discussed.

  13. Increasing the range accuracy of three-dimensional ghost imaging ladar using optimum slicing number method

    NASA Astrophysics Data System (ADS)

    Yang, Xu; Zhang, Yong; Xu, Lu; Yang, Cheng-Hua; Wang, Qiang; Liu, Yue-Hao; Zhao, Yuan

    2015-12-01

    The range accuracy of three-dimensional (3D) ghost imaging is derived. Based on the derived range accuracy equation, the relationship between the slicing number and the range accuracy is analyzed and an optimum slicing number (OSN) is determined. According to the OSN, an improved 3D ghost imaging algorithm is proposed to increase the range accuracy. Experimental results indicate that the slicing number can affect the range accuracy significantly and the highest range accuracy can be achieved if the 3D ghost imaging system works with OSN. Project supported by the Young Scientist Fund of the National Natural Science Foundation of China (Grant No. 61108072).

  14. 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.

  15. Atmospheric effects and ultimate ranging accuracy for lunar laser ranging

    NASA Astrophysics Data System (ADS)

    Currie, Douglas G.; Prochazka, Ivan

    2014-10-01

    The deployment of next generation lunar laser retroreflectors is planned in the near future. With proper robotic deployment, these will support single shot single photo-electron ranging accuracy at the 100 micron level or better. There are available technologies for the support at this accuracy by advanced ground stations, however, the major question is the ultimate limit imposed on the ranging accuracy due to the changing timing delays due to turbulence and horizontal gradients in the earth's atmosphere. In particular, there are questions of the delay and temporal broadening of a very narrow laser pulse. Theoretical and experimental results will be discussed that address estimates of the magnitudes of these effects and the issue of precision vs. accuracy.

  16. The construction of high-accuracy schemes for acoustic equations

    NASA Technical Reports Server (NTRS)

    Tang, Lei; Baeder, James D.

    1995-01-01

    An accuracy analysis of various high order schemes is performed from an interpolation point of view. The analysis indicates that classical high order finite difference schemes, which use polynomial interpolation, hold high accuracy only at nodes and are therefore not suitable for time-dependent problems. Thus, some schemes improve their numerical accuracy within grid cells by the near-minimax approximation method, but their practical significance is degraded by maintaining the same stencil as classical schemes. One-step methods in space discretization, which use piecewise polynomial interpolation and involve data at only two points, can generate a uniform accuracy over the whole grid cell and avoid spurious roots. As a result, they are more accurate and efficient than multistep methods. In particular, the Cubic-Interpolated Psuedoparticle (CIP) scheme is recommended for computational acoustics.

  17. Accuracy testing of a new intraoral 3D camera.

    PubMed

    Mehl, A; Ender, A; Mörmann, W; Attin, T

    2009-01-01

    Surveying intraoral structures by optical means has reached the stage where it is being discussed as a serious clinical alternative to conventional impression taking. Ease of handling and, more importantly, accuracy are important criteria for the clinical suitability of these systems. This article presents a new intraoral camera for the Cerec procedure. It reports on a study investigating the accuracy of this camera and its potential clinical indications. Single-tooth and quadrant images were taken with the camera and the results compared to those obtained with a reference scanner and with the previous 3D camera model. Differences were analyzed by superimposing the data records. Accuracy was higher with the new camera than with the previous model, reaching up to 19 microm in single-tooth images. Quadrant images can also be taken with sufficient accuracy (ca 35 microm) and are simple to perform in clinical practice, thanks to built-in shake detection in automatic capture mode.

  18. 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.

  19. 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.

  20. Collective animal decisions: preference conflict and decision accuracy

    PubMed Central

    Conradt, Larissa

    2013-01-01

    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. PMID:24516716

  1. 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.

  2. Accuracy of the domain method for the material derivative approach to shape design sensitivities

    NASA Technical Reports Server (NTRS)

    Yang, R. J.; Botkin, M. E.

    1987-01-01

    Numerical accuracy for the boundary and domain methods of the material derivative approach to shape design sensitivities is investigated through the use of mesh refinement. The results show that the domain method is generally more accurate than the boundary method, using the finite element technique. It is also shown that the domain method is equivalent, under certain assumptions, to the implicit differentiation approach not only theoretically but also numerically.

  3. 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

  4. The neural bases of empathic accuracy

    PubMed Central

    Zaki, Jamil; Weber, Jochen; Bolger, Niall; Ochsner, Kevin

    2009-01-01

    Theories of empathy suggest that an accurate understanding of another's emotions should depend on affective, motor, and/or higher cognitive brain regions, but until recently no experimental method has been available to directly test these possibilities. Here, we present a functional imaging paradigm that allowed us to address this issue. We found that empathically accurate, as compared with inaccurate, judgments depended on (i) structures within the human mirror neuron system thought to be involved in shared sensorimotor representations, and (ii) regions implicated in mental state attribution, the superior temporal sulcus and medial prefrontal cortex. These data demostrate that activity in these 2 sets of brain regions tracks with the accuracy of attributions made about another's internal emotional state. Taken together, these results provide both an experimental approach and theoretical insights for studying empathy and its dysfunction. PMID:19549849

  5. 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.

  6. 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.

  7. 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.

  8. Accuracy of Four Tooth Size Prediction Methods on Malay Population

    PubMed Central

    Mahmoud, Belal Khaled; Abu Asab, Saifeddin Hamed I.; Taib, Haslina

    2012-01-01

    Objective. To examine the accuracy of Moyers 50%, Tanaka and Johnston, Ling and Wong and Jaroontham and Godfrey methods in predicting the mesio-distal crown width of the permanent canines and premolars (C + P1 + P2) in Malay population. Materials and Methods. The study models of 240 Malay children (120 males and 120 females) aged 14 to 18 years, all free of any signs of dental pathology or anomalies, were measured using a digital caliper accurate to 0.01 mm. The predicted widths (C + P1 + P2) in both arches derived from the tested prediction equations were compared with the actual measured widths. Results. Moyers and Tanaka and Johnston methods showed significant difference between the actual and predicted widths of (C + P1 + P2) for both sexes. Ling and Wong method also showed statistically significant difference for males, however, there was no significant difference for females. Jaroontham and Godfrey method showed statistical significant difference for females, but the male values did not show any significant difference. Conclusion. For male Malay, the method proposed by Jaroontham and Godfrey for male Thai proved to be highly accurate. For female Malay, the method proposed by Ling and Wong for southern Chinese females proved to be highly accurate. PMID:23209918

  9. 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

  10. Meteor orbit determination with improved accuracy

    NASA Astrophysics Data System (ADS)

    Dmitriev, Vasily; Lupovla, Valery; Gritsevich, Maria

    2015-08-01

    Modern observational techniques make it possible to retrive meteor trajectory and its velocity with high accuracy. There has been a rapid rise in high quality observational data accumulating yearly. This fact creates new challenges for solving the problem of meteor orbit determination. Currently, traditional technique based on including corrections to zenith distance and apparent velocity using well-known Schiaparelli formula is widely used. Alternative approach relies on meteoroid trajectory correction using numerical integration of equation of motion (Clark & Wiegert, 2011; Zuluaga et al., 2013). In our work we suggest technique of meteor orbit determination based on strict coordinate transformation and integration of differential equation of motion. We demonstrate advantage of this method in comparison with traditional technique. We provide results of calculations by different methods for real, recently occurred fireballs, as well as for simulated cases with a priori known retrieval parameters. Simulated data were used to demonstrate the condition, when application of more complex technique is necessary. It was found, that for several low velocity meteoroids application of traditional technique may lead to dramatically delusion of orbit precision (first of all, due to errors in Ω, because this parameter has a highest potential accuracy). Our results are complemented by analysis of sources of perturbations allowing to quantitatively indicate which factors have to be considered in orbit determination. In addition, the developed method includes analysis of observational error propagation based on strict covariance transition, which is also presented.Acknowledgements. This work was carried out at MIIGAiK and supported by the Russian Science Foundation, project No. 14-22-00197.References:Clark, D. L., & Wiegert, P. A. (2011). A numerical comparison with the Ceplecha analytical meteoroid orbit determination method. Meteoritics & Planetary Science, 46(8), pp. 1217

  11. High-accuracy fuel flowmeter. Phase 2C and 3: The mass flow-rate calibration of high-accuracy fuel flowmeters. Final Report

    SciTech Connect

    Craft, D.W.

    1992-02-01

    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.

  12. Detection of the spatial accuracy of an O-arm in the region of surgical interest

    NASA Astrophysics Data System (ADS)

    Koivukangas, Tapani; Katisko, Jani P. A.; Koivukangsa, John P.

    2013-03-01

    Medical imaging is an essential component of a wide range of surgical procedures1. For image guided surgical (IGS) procedures, medical images are the main source of information2. The IGS procedures rely largely on obtained image data, so the data needs to provide differentiation between normal and abnormal tissues, especially when other surgical guidance devices are used in the procedures. The image data also needs to provide accurate spatial representation of the patient3. This research has concentrated on the concept of accuracy assessment of IGS devices to meet the needs of quality assurance in the hospital environment. For this purpose, two precision engineered accuracy assessment phantoms have been developed as advanced materials and methods for the community. The phantoms were designed to mimic the volume of a human head as the common region of surgical interest (ROSI). This paper introduces the utilization of the phantoms in spatial accuracy assessment of a commercial surgical 3D CT scanner, the O-Arm. The study presents methods and results of image quality detection of possible geometrical distortions in the region of surgical interest. The results show that in the pre-determined ROSI there are clear image distortion and artefacts using too high imaging parameters when scanning the objects. On the other hand, when using optimal parameters, the O-Arm causes minimal error in IGS accuracy. The detected spatial inaccuracy of the O-Arm with used parameters was in the range of less than 1.00 mm.

  13. Design of a low noise and high accuracy readout integrated circuit for infrared detectors

    NASA Astrophysics Data System (ADS)

    Yang, Dong; Zhou, Hang-yu; Wang, Jian

    2011-08-01

    In this paper, a low noise and high accuracy readout integrated circuit (ROIC) for Infrared detectors is presented. The circuit is made up of capacitor trans-impedance amplifier (CTIA) and correlation double sampling (CDS) circuit. First, the accuracy, and injection efficiency of the CTIA structure which is used to convert the photo-current into voltage are fully discussed. The readout accuracy of weak current signal can be obviously improved by the using of CTIA. Then, the CDS structure with offset calibration technique is used to reduce the fixed pattern noise (FPN) of CTIA. Thus, the signal to noise ratio (SNR) of the designed readout circuit is improved. By utilizing the above two techniques, the influence of noise on this circuit was greatly reduced and the precision of the ROIC was improved. Besides, the design of amplifier in CTIA is discussed in more detail, which will bring about important effect on performance of the whole circuit. Simulation results at Cadence Spectre demonstrated that the readout circuit had reached the requirement of application. The final chip was fabricated with Chartered 0.35um standard CMOS process. Testing results show that the linearity of CTIA is 99%, and that the readout accuracy is 10-bit, while the detecting current varies from 10pA to 10nA. Furthermore, the infrared image is shown in this paper, which means that the ROIC has a good performance at the practical application.

  14. 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.

  15. 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.

  16. Determining the accuracy of maximum likelihood parameter estimates with colored residuals

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.; Klein, Vladislav

    1994-01-01

    An important part of building high fidelity mathematical models based on measured data is calculating the accuracy associated with statistical estimates of the model parameters. Indeed, without some idea of the accuracy of parameter estimates, the estimates themselves have limited value. In this work, an expression based on theoretical analysis was developed to properly compute parameter accuracy measures for maximum likelihood estimates with colored residuals. This result is important because experience from the analysis of measured data reveals that the residuals from maximum likelihood estimation are almost always colored. The calculations involved can be appended to conventional maximum likelihood estimation algorithms. Simulated data runs were used to show that the parameter accuracy measures computed with this technique accurately reflect the quality of the parameter estimates from maximum likelihood estimation without the need for analysis of the output residuals in the frequency domain or heuristically determined multiplication factors. The result is general, although the application studied here is maximum likelihood estimation of aerodynamic model parameters from flight test data.

  17. An other perspective on personality: meta-analytic integration of observers' accuracy and predictive validity.

    PubMed

    Connelly, Brian S; Ones, Deniz S

    2010-11-01

    The bulk of personality research has been built from self-report measures of personality. However, collecting personality ratings from other-raters, such as family, friends, and even strangers, is a dramatically underutilized method that allows better explanation and prediction of personality's role in many domains of psychology. Drawing hypotheses from D. C. Funder's (1995) realistic accuracy model about trait and information moderators of accuracy, we offer 3 meta-analyses to help researchers and applied psychologists understand and interpret both consistencies and unique insights afforded by other-ratings of personality. These meta-analyses integrate findings based on 44,178 target individuals rated across 263 independent samples. Each meta-analysis assessed the accuracy of observer ratings, as indexed by interrater consensus/reliability (Study 1), self-other correlations (Study 2), and predictions of behavior (Study 3). The results show that although increased frequency of interacting with targets does improve accuracy in rating personality, informants' interpersonal intimacy with the target is necessary for substantial increases in other-rating accuracy. Interpersonal intimacy improved accuracy especially for traits low in visibility (e.g., Emotional Stability) but only minimally for traits high in evaluativeness (e.g., Agreeableness). In addition, observer ratings were strong predictors of behaviors. When the criterion was academic achievement or job performance, other-ratings yielded predictive validities substantially greater than and incremental to self-ratings. These findings indicate that extraordinary value can gained by using other-reports to measure personality, and these findings provide guidelines toward enriching personality theory. Various subfields of psychology in which personality variables are systematically assessed and utilized in research and practice can benefit tremendously from use of others' ratings to measure personality variables.

  18. On the accuracy of close stellar approaches determination

    NASA Astrophysics Data System (ADS)

    Dybczyński, Piotr A.; Berski, Filip

    2015-05-01

    The aim of this paper is to demonstrate the accuracy of our knowledge of close stellar passage distances in the pre-Gaia era. We used the most precise astrometric and kinematic data available at the moment and prepared a list of 40 stars nominally passing (in the past or future) closer than 2 pc from the Sun. We used a full gravitational potential of the Galaxy to calculate the motion of the Sun and a star from their current positions to the proximity epoch. For these calculations, we used a numerical integration in rectangular, Galactocentric coordinates. We showed that in many cases the numerical integration of the star motion gives significantly different results than popular rectilinear approximation. We found several new stellar candidates for close visitors in past or in future. We used covariance matrices of the astrometric data for each star to estimate the accuracy of the obtained proximity distance and epoch. To this aim, we used a Monte Carlo method, replaced each star with 10 000 of its clones and studied the distribution of their individual close passages near the Sun. We showed that for contemporary close neighbours the precision is quite good, but for more distant stars it strongly depends on the quality of astrometric and kinematic data. Several examples are discussed in detail, among them the case of HIP 14473. For this star, we obtained the nominal proximity distance as small as 0.22 pc 3.78 Myr ago. However, there exists strong need for more precise astrometry of this star since the proximity point uncertainty is unacceptably large.

  19. Contribution of the AIRS Shortwave Sounding Channels to Retrieval Accuracy

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Kouvaris, Louis

    2006-01-01

    AIRS contains 2376 high spectral resolution channels between 650/cm and 2665/cm, including channels in both the 15 micron (near 667/cm) and 4.2 micron (near 2400/cm) COP sounding bands. Use of temperature sounding channels in the 15 micron CO2 band has considerable heritage in infra-red remote sensing. Channels in the 4.2 micron CO2 band have potential advantages for temperature sounding purposes because they are essentially insensitive to absorption by water vapor and ozone, and also have considerably sharper lower tropospheric temperature sounding weighting functions than do the 15 micron temperature sounding channels. Potential drawbacks with regard to use of 4.2 micron channels arise from effects on the observed radiances of solar radiation reflected by the surface and clouds, as well as effects of non-local thermodynamic equilibrium on shortwave observations during the day. These are of no practical consequences, however, when properly accounted for. We show results of experiments performed utilizing different spectral regions of AIRS, conducted with the AIRS Science Team candidate Version 5 algorithm. Experiments were performed using temperature sounding channels within the entire AIRS spectral coverage, within only the spectral region 650/cm to 1614 /cm; and within only the spectral region 1000/cm-2665/cm. These show the relative importance of utilizing only 15 micron temperature sounding channels, only the 4.2 micron temperature sounding channels, and both, with regards to sounding accuracy. The spectral region 2380/cm to 2400/cm is shown to contribute significantly to improve sounding accuracy in the lower troposphere, both day and night.

  20. 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

  1. Differences between experts and novices in kinematics and accuracy of golf putting.

    PubMed

    Sim, Mikyong; Kim, Jin-Uk

    2010-12-01

    In this study, golf-putting movements were examined under three goal distances (short, 1.7m; middle, 3.25m; long, 6m), two different putter weights (500g, 750g), and two levels of expertise (5 experts, 5 novices). The study's aim was to identify differences in kinematics and accuracy between expert and novice golfers. The results demonstrated that experts achieved higher accuracy with lower impact velocity than novices. In addition, while novices showed symmetrical movements, experts exhibited asymmetrical movements, which were achieved by modulating their movement time and amplitude differently from novices. These results demonstrated differences in relative timing, relative amplitude and velocity, but no difference in time-to-contact between novices and experts. The results reaffirmed the role of prior learning and supported the hypothesis of Manoel and Connolly (1995) that motor learning is a hierarchical process organized at both macroscopic and microscopic levels. PMID:20846738

  2. Diagnostic accuracy of existing methods for identifying diabetic foot ulcers from inpatient and outpatient datasets

    PubMed Central

    2010-01-01

    Background As the number of persons with diabetes is projected to double in the next 25 years in the US, an accurate method of identifying diabetic foot ulcers in population-based data sources are ever more important for disease surveillance and public health purposes. The objectives of this study are to evaluate the accuracy of existing methods and to propose a new method. Methods Four existing methods were used to identify all patients diagnosed with a foot ulcer in a Department of Veterans Affairs (VA) hospital from the inpatient and outpatient datasets for 2003. Their electronic medical records were reviewed to verify whether the medical records positively indicate presence of a diabetic foot ulcer in diagnoses, medical assessments, or consults. For each method, five measures of accuracy and agreement were evaluated using data from medical records as the gold standard. Results Our medical record reviews show that all methods had sensitivity > 92% but their specificity varied substantially between 74% and 91%. A method used in Harrington et al. (2004) was the most accurate with 94% sensitivity and 91% specificity and produced an annual prevalence of 3.3% among VA users with diabetes nationwide. A new and simpler method consisting of two codes (707.1× and 707.9) shows an equally good accuracy with 93% sensitivity and 91% specificity and 3.1% prevalence. Conclusions Our results indicate that the Harrington and New methods are highly comparable and accurate. We recommend the Harrington method for its accuracy and the New method for its simplicity and comparable accuracy. PMID:21106076

  3. 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.

  4. Research of measuring accuracy of laser tracker system

    NASA Astrophysics Data System (ADS)

    Ouyang, Jianfei; Liang, Zhiyong; Zhang, Haixin; Yan, Yonggang

    2006-11-01

    This paper presents the achievement of a China NSFC project. The Laser Tracker System (LTS) is a portable 3D large size measuring system. The measuring conditions such as time and temperature can greatly affect the measuring accuracy of LTS. This paper pays a great attention to study how the time and temperature affect the measuring accuracy of LTS. Coordinate Measuring Machine (CMM) is employed as a high-level measuring instrument to validate LTS. The experiments have been done to find how the time and temperature affect the measuring accuracy of LTS. The experiments show the LTS can work well with the highest measuring accuracy just after three-hour warm-up. However, the LTS becomes unstable and the measuring accuracy decreases after 10 hours. The LTS needs calibration and compensation every 10 hours. The experiments show that the measuring error can be up to 29.6μm when the measuring temperature is 30.5°C even if the measuring error is less than 5.9μm while the temperature is between 20°C and 23.8°C. The research provides a very useful guidance for application of LTS.

  5. Pulse oximetry: accuracy of methods of interpreting graphic summaries.

    PubMed

    Lafontaine, V M; Ducharme, F M; Brouillette, R T

    1996-02-01

    Although pulse oximetry has been used to determine the frequency and extent of hemoglobin desaturation during sleep, movement artifact can result in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pulmonologists' and technicians' interpretations of graphic displays of desaturation events, derived an objective method for interpreting such events, and validated the method on an independent data set. Eighty-seven randomly selected desaturation events were classified as valid (58) or artifactual (29) based on cardiorespiratory recordings (gold standard) that included pulse waveform and respiratory inductive plethysmography signals. Using oximetry recordings (test method), nine pediatric pulmonologists and three respiratory technicians ("readers") averaged 50 +/- 11% (SD) accuracy for event classification. A single variable, the pulse amplitude modulation range (PAMR) prior to desaturation, performed better in discriminating valid from artifactual events with 76% accuracy (P < 0.05). Following a seminar on oximetry and the use of the PAMR method, the readers' accuracy increased to 73 +/- 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% artifactual), the PAMR method of assessing oximetry graphs yielded 82% accuracy; transcutaneous oxygen tension records confirmed a drop in oxygenation during 49 of 54 (89%) valid desaturation events. In conclusion, the most accurate method (91%) of assessing desaturation events requires recording of the pulse and respiratory waveforms. However, a practical, easy-to-use method of interpreting pulse oximetry recordings achieved 76-82% accuracy, which constitutes a significant improvement from previous subjective interpretations.

  6. 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. PMID:27625628

  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 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.

  9. Voyager navigation strategy and accuracy

    NASA Technical Reports Server (NTRS)

    Jones, J. B.; Mcdanell, J. P.; Bantell, M. H., Jr.; Chadwick, C.; Jacobson, R. A.; Miller, L. J.; Synnott, S. P.; Van Allen, R. E.

    1977-01-01

    The paper presents the results of the prelaunch navigation studies conducted for the Mariner spacecraft launched toward encounters with the giant planets. The navigation system and the strategy for using this system are described. The requirements on the navigation system demanded by the goals of the project are mentioned, and the predicted navigational capability relative to each of the requirements is discussed. Baseline navigation results for three possible trajectories are analyzed.

  10. Effect of time discretization of the imaging process on the accuracy of trajectory estimation in fluorescence microscopy.

    PubMed

    Wong, Yau; Chao, Jerry; Lin, Zhiping; Ober, Raimund J

    2014-08-25

    In fluorescence microscopy, high-speed imaging is often necessary for the proper visualization and analysis of fast subcellular dynamics. Here, we examine how the speed of image acquisition affects the accuracy with which parameters such as the starting position and speed of a microscopic non-stationary fluorescent object can be estimated from the resulting image sequence. Specifically, we use a Fisher information-based performance bound to investigate the detector-dependent effect of frame rate on the accuracy of parameter estimation. We demonstrate that when a charge-coupled device detector is used, the estimation accuracy deteriorates as the frame rate increases beyond a point where the detector's readout noise begins to overwhelm the low number of photons detected in each frame. In contrast, we show that when an electron-multiplying charge-coupled device (EMCCD) detector is used, the estimation accuracy improves with increasing frame rate. In fact, at high frame rates where the low number of photons detected in each frame renders the fluorescent object difficult to detect visually, imaging with an EMCCD detector represents a natural implementation of the Ultrahigh Accuracy Imaging Modality, and enables estimation with an accuracy approaching that which is attainable only when a hypothetical noiseless detector is used. PMID:25321248

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Accuracy of Carbohydrate Counting in Adults.

    PubMed

    Meade, Lisa T; Rushton, Wanda E

    2016-07-01

    In Brief This study investigates carbohydrate counting accuracy in patients using insulin through a multiple daily injection regimen or continuous subcutaneous insulin infusion. The average accuracy test score for all patients was 59%. The carbohydrate test in this study can be used to emphasize the importance of carbohydrate counting to patients and to provide ongoing education. PMID:27621531

  16. Scientific Sources' Perception of Network News Accuracy.

    ERIC Educational Resources Information Center

    Moore, Barbara; Singletary, Michael

    Recent polls seem to indicate that many Americans rely on television as a credible and primary source of news. To test the accuracy of this news, a study examined three networks' newscasts of science news, the attitudes of the science sources toward reporting in their field, and the factors related to accuracy. The Vanderbilt News Archives Index…

  17. 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…

  18. 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…

  19. 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.

  20. Early-Onset Neonatal Sepsis: Still Room for Improvement in Procalcitonin Diagnostic Accuracy Studies.

    PubMed

    Chiesa, Claudio; Pacifico, Lucia; Osborn, John F; Bonci, Enea; Hofer, Nora; Resch, Bernhard

    2015-07-01

    To perform a systematic review assessing accuracy and completeness of diagnostic studies of procalcitonin (PCT) for early-onset neonatal sepsis (EONS) using the Standards for Reporting of Diagnostic Accuracy (STARD) initiative.EONS, diagnosed during the first 3 days of life, remains a common and serious problem. Increased PCT is a potentially useful diagnostic marker of EONS, but reports in the literature are contradictory. There are several possible explanations for the divergent results including the quality of studies reporting the clinical usefulness of PCT in ruling in or ruling out EONS.We systematically reviewed PubMed, Scopus, and the Cochrane Library databases up to October 1, 2014. Studies were eligible for inclusion in our review if they provided measures of PCT accuracy for diagnosing EONS. A data extraction form based on the STARD checklist and adapted for neonates with EONS was used to appraise the quality of the reporting of included studies.We found 18 articles (1998-2014) fulfilling our eligibility criteria which were included in the final analysis. Overall, the results of our analysis showed that the quality of studies reporting diagnostic accuracy of PCT for EONS was suboptimal leaving ample room for improvement. Information on key elements of design, analysis, and interpretation of test accuracy were frequently missing.Authors should be aware of the STARD criteria before starting a study in this field. We welcome stricter adherence to this guideline. Well-reported studies with appropriate designs will provide more reliable information to guide decisions on the use and interpretations of PCT test results in the management of neonates with EONS.

  1. Application of bias correction methods to improve the accuracy of quantitative radar rainfall in Korea

    NASA Astrophysics Data System (ADS)

    Lee, J.-K.; Kim, J.-H.; Suk, M.-K.

    2015-04-01

    There are many potential sources of bias in the radar rainfall estimation process. This study classified the biases from the rainfall estimation process into the reflectivity measurement bias and QPE model bias and also conducted the bias correction methods to improve the accuracy of the Radar-AWS Rainrate (RAR) calculation system operated by the Korea Meteorological Administration (KMA). For the Z bias correction, this study utilized the bias correction algorithm for the reflectivity. The concept of this algorithm is that the reflectivity of target single-pol radars is corrected based on the reference dual-pol radar corrected in the hardware and software bias. This study, and then, dealt with two post-process methods, the Mean Field Bias Correction (MFBC) method and the Local Gauge Correction method (LGC), to correct rainfall-bias. The Z bias and rainfall-bias correction methods were applied to the RAR system. The accuracy of the RAR system improved after correcting Z bias. For rainfall types, although the accuracy of Changma front and local torrential cases was slightly improved without the Z bias correction, especially, the accuracy of typhoon cases got worse than existing results. As a result of the rainfall-bias correction, the accuracy of the RAR system performed Z bias_LGC was especially superior to the MFBC method because the different rainfall biases were applied to each grid rainfall amount in the LGC method. For rainfall types, Results of the Z bias_LGC showed that rainfall estimates for all types was more accurate than only the Z bias and, especially, outcomes in typhoon cases was vastly superior to the others.

  2. [Accuracy and precision in the evaluation of computer assisted surgical systems. A definition].

    PubMed

    Strauss, G; Hofer, M; Korb, W; Trantakis, C; Winkler, D; Burgert, O; Schulz, T; Dietz, A; Meixensberger, J; Koulechov, K

    2006-02-01

    Accuracy represents the outstanding criterion for navigation systems. Surgeons have noticed a great discrepancy between the values from the literature and system specifications on one hand, and intraoperative accuracy on the other. A unitary understanding for the term accuracy does not exist in clinical practice. Furthermore, an incorrect equality for the terms precision and accuracy can be found in the literature. On top of this, clinical accuracy differs from mechanical (technical) accuracy. From a clinical point of view, we had to deal with remarkably many different terms all describing accuracy. This study has the goals of: 1. Defining "accuracy" and related terms, 2. Differentiating between "precision" and "accuracy", 3. Deriving the term "surgical accuracy", 4. Recommending use of the the term "surgical accuracy" for a navigation system. To a great extent, definitions were applied from the International Standardisation Organisation-ISO and the norm from the Deutsches Institut für Normung e.V.-DIN (the German Institute for Standardization). For defining surgical accuracy, the terms reference value, expectation, accuracy and precision are of major interest. Surgical accuracy should indicate the maximum values for the deviation between test results and the reference value (true value) A(max), and additionally indicate precision P(surg). As a basis for measurements, a standardized technical model was used. Coordinates of the model were acquired by CT. To determine statistically and reality relevant results for head surgery, 50 measurements with an accuracy of 50, 75, 100 and 150 mm from the centre of the registration geometry are adequate. In the future, we recommend labeling the system's overall performance with the following specifications: maximum accuracy deviation A(max), precision P and information on the measurement method. This could be displayed on a seal of quality.

  3. 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.

  4. The effects of aging on the speed-accuracy compromise: Boundary optimality in the diffusion model.

    PubMed

    Starns, Jeffrey J; Ratcliff, Roger

    2010-06-01

    We evaluated age-related differences in the optimality of decision boundary settings in a diffusion model analysis. In the model, the width of the decision boundary represents the amount of evidence that must accumulate in favor of a response alternative before a decision is made. Wide boundaries lead to slow but accurate responding, and narrow boundaries lead to fast but inaccurate responding. There is a single value of boundary separation that produces the most correct answers in a given period of time, and we refer to this value as the reward rate optimal boundary (RROB). We consistently found across a variety of decision tasks that older adults used boundaries that were much wider than the RROB value. Young adults used boundaries that were closer to the RROB value, although age differences in optimality were smaller with instructions emphasizing speed than with instructions emphasizing accuracy. Young adults adjusted their boundary settings to more closely approach the RROB value when they were provided with accuracy feedback and extensive practice. Older participants showed no evidence of making boundary adjustments in response to feedback or task practice, and they consistently used boundary separation values that produced accuracy levels that were near asymptote. Our results suggest that young adults attempt to balance speed and accuracy to achieve the most correct answers per unit time, whereas older adultts attempt to minimize errors even if they must respond quite slowly to do so.

  5. The prediction of the hepatic clearance of tanshinone IIA in rat liver subcellular fractions: accuracy improvement.

    PubMed

    Li, Peng; Wang, Guang-Ji; Li, Jing; Zhang, Qian; Liu, Xin; Khlentzos, Alexander; Roberts, Michael S

    2008-01-01

    The in vivo hepatic clearance of tanshinone IIA in the rat was predicted using microsome, cytosol and S9 fractions combined with two different cofactor systems, NADPH-regenerating and UDPGA system. Two different models, the well stirred model and the parallel-tube model, were used in predicting the in vivo clearance in the rat. The in vivo clearance of tanshinone IIA was acquired from a pharmacokinetic study in rat. The results show that the prediction accuracy acquired from the microsome combined with the NADPH is poor. The in vivo clearance in the rat is almost 32 fold higher than the clearance predicted in microsome. The predicted clearance of the S9 model combined with both NADPH and UDPGA system is about 4 fold lower than the in vivo clearance. The predicted clearance of the cytosol combined with the two cofactor system is about 7 fold lower than the in vivo clearance. Although the prediction accuracy acquired from the S9 and cytosol system is not perfect, the prediction accuracy is improved in these two incubation systems. Using S9 combined with both the phase I and phase II metabolism can improve the prediction accuracy. PMID:18220570

  6. 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. PMID:25271816

  7. 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.

  8. 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.

  9. Domain-specific impairment in metacognitive accuracy following anterior prefrontal lesions

    PubMed Central

    Ryu, Jihye; Golfinos, John G.; Blackmon, Karen E.

    2014-01-01

    Humans have the capacity to evaluate the success of cognitive processes, known as metacognition. Convergent evidence supports a role for anterior prefrontal cortex in metacognitive judgements of perceptual processes. However, it is unknown whether metacognition is a global phenomenon, with anterior prefrontal cortex supporting metacognition across domains, or whether it relies on domain-specific neural substrates. To address this question, we measured metacognitive accuracy in patients with lesions to anterior prefrontal cortex (n = 7) in two distinct domains, perception and memory, by assessing the correspondence between objective performance and subjective ratings of performance. Despite performing equivalently to a comparison group with temporal lobe lesions (n = 11) and healthy controls (n = 19), patients with lesions to the anterior prefrontal cortex showed a selective deficit in perceptual metacognitive accuracy (meta-d’/d’, 95% confidence interval 0.28–0.64). Crucially, however, the anterior prefrontal cortex lesion group’s metacognitive accuracy on an equivalent memory task remained unimpaired (meta-d’/d’, 95% confidence interval 0.78–1.29). Metacognitive accuracy in the temporal lobe group was intact in both domains. Our results support a causal role for anterior prefrontal cortex in perceptual metacognition, and indicate that the neural architecture of metacognition, while often considered global and domain-general, comprises domain-specific components that may be differentially affected by neurological insult. PMID:25100039

  10. An effective approach to improving low-cost GPS positioning accuracy in real-time navigation.

    PubMed

    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.

  11. 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

  12. Accuracy of fuzzy burned area mapping as a function of the aerosol parameterization of atmospheric correction

    NASA Astrophysics Data System (ADS)

    Azar, Ramin; Stroppiana, Daniela; Bresciani, Mariano; Giardino, Claudia; Boschetti, Mirco; Brivio, Pietro A.

    2013-10-01

    Mediterranean forests are every year affected by wildfires which have a significant effect on the ecosystem. Mapping burned areas is an important field of application for optical remote sensing techniques and several methodologies have been developed in order to improve mapping accuracy. We developed an automated procedure based on spectral indices and fuzzy theory for mapping burned areas from atmospherically corrected Landsat TM images. The algorithm proved to provide consistent accuracy over Mediterranean areas. We further tested algorithm's performance to assess the influence of the atmospheric correction on the accuracy of burned areas. In particular, we ran the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) code with different Atmospheric Optical Thickness (AOT) levels and two aerosol models (continental and maritime) on one TM image acquired over Portugal (12/08/2003). Burned area maps derived from atmospherically corrected images and from the non corrected image (Top Of Atmosphere, TOA) have been analyzed. In the output burned areas maps the omission error varies in the range 4.6-6.5% and the commission error fluctuates between 11.9 and 22.2%; the highest omission (commission) errors occur with the continental (maritime) model. The accuracy of burned area maps derived from non corrected image is very low, with omission error greater than 90%. These results show that, although atmospheric correction is needed for the application of the algorithm, the AOT value does not significantly affect the performance.

  13. Accuracy and computational efficiency of real-time subspace propagation schemes for the time-dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Russakoff, Arthur; Li, Yonghui; He, Shenglai; Varga, Kalman

    2016-05-01

    Time-dependent Density Functional Theory (TDDFT) has become successful for its balance of economy and accuracy. However, the application of TDDFT to large systems or long time scales remains computationally prohibitively expensive. In this paper, we investigate the numerical stability and accuracy of two subspace propagation methods to solve the time-dependent Kohn-Sham equations with finite and periodic boundary conditions. The bases considered are the Lánczos basis and the adiabatic eigenbasis. The results are compared to a benchmark fourth-order Taylor expansion of the time propagator. Our results show that it is possible to use larger time steps with the subspace methods, leading to computational speedups by a factor of 2-3 over Taylor propagation. Accuracy is found to be maintained for certain energy regimes and small time scales.

  14. 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.

  15. COMPASS time synchronization and dissemination—Toward centimetre positioning accuracy

    NASA Astrophysics Data System (ADS)

    Wang, ZhengBo; Zhao, Lu; Wang, ShiGuang; Zhang, JianWei; Wang, Bo; Wang, LiJun

    2014-09-01

    In this paper we investigate methods to achieve highly accurate time synchronization among the satellites of the COMPASS global navigation satellite system (GNSS). Owing to the special design of COMPASS which implements several geo-stationary satellites (GEO), time synchronization can be highly accurate via microwave links between ground stations to the GEO satellites. Serving as space-borne relay stations, the GEO satellites can further disseminate time and frequency signals to other satellites such as the inclined geo-synchronous (IGSO) and mid-earth orbit (MEO) satellites within the system. It is shown that, because of the accuracy in clock synchronization, the theoretical accuracy of COMPASS positioning and navigation will surpass that of the GPS. In addition, the COMPASS system can function with its entire positioning, navigation, and time-dissemination services even without the ground link, thus making it much more robust and secure. We further show that time dissemination using the COMPASS-GEO satellites to earth-fixed stations can achieve very high accuracy, to reach 100 ps in time dissemination and 3 cm in positioning accuracy, respectively. In this paper, we also analyze two feasible synchronization plans. All special and general relativistic effects related to COMPASS clocks frequency and time shifts are given. We conclude that COMPASS can reach centimeter-level positioning accuracy and discuss potential applications.

  16. Improving Accuracy of Image Classification Using GIS

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Prasad, T. S.; Bala Manikavelu, P. M.; Vijayan, D.

    had been the point of examination in this research contribution. The research was carried out over the forest region for which a ground based GIS had been available. This forest consists of 9 classes viz., Dense Forest, Settlement, Teak, Bamboo, Grass Lands, Mixed Forests, Podu/Blanks, Semi-evergreen forest and Water bodies. Working over this forest region, it was found that the classification accuracy got improved from 69.5% to 73% by using GIS. Thereafter, the improvement in accuracy through iterative process was examined. The a priori probability for a given class during next iteration was assigned based on the ratio of the number of pixels in a given class to the total number of pixels in the classified image. The iteration was continued till the percentage change in area (i.e., number of pixels) in any of the class was less than 3 per cent with reference to previous iteration. The iterative process led to asymptotic situation after three iterations when ML classification was repeated without the use of GIS. For the situation, where GIS vector overlay was used, the asymptotic condition was nearly achieved after four iterations; a total of seven iterations were undertaken. The iteration without the use of GIS could improve the classification accuracy by about 1.5% (3 iterations) while about 13% improvement in 4 iterations was achieved when information available in GIS vector layer were used. Though, there was overlap in spectral signatures for bamboo, teak and mixed forests in green, red and near IR bands; the very different higher end limit for bamboo (as compared to values for teak and mixed forest) in near IR band, no overlap for teak (as compared to values for bamboo and mixed forest) in green band, and very little overlap in upper limit of mixed forests and lower limit of bamboo in red band were found to be the discriminating factors. Besides discussing these aspects, paper would address to other associated diagnostics to explain the results in how and why

  17. Range accuracy analysis of streak tube imaging lidar systems

    NASA Astrophysics Data System (ADS)

    Ye, Guangchao; Fan, Rongwei; Chen, Zhaodong; Yuan, Wei; Chen, Deying; He, Ping

    2016-02-01

    Streak tube imaging lidar (STIL) is an active imaging system that has a high range accuracy and a wide range gate with the use of a pulsed laser transmitter and streak tube receiver to produce 3D range images. This work investigates the range accuracy performance of STIL systems based on a peak detection algorithm, taking into account the effects of blurring of the image. A theoretical model of the time-resolved signal distribution, including the static blurring width in addition to the laser pulse width, is presented, resulting in a modified range accuracy analysis. The model indicates that the static blurring width has a significant effect on the range accuracy, which is validated by both the simulation and experimental results. By using the optimal static blurring width, the range accuracies are enhanced in both indoor and outdoor experiments, with a stand-off distance of 10 m and 1700 m, respectively, and corresponding, best range errors of 0.06 m and 0.25 m were achieved in a daylight environment.

  18. 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…

  19. 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

  20. 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

  1. A novel small area fast block matching algorithm based on high-accuracy gyro in digital image stabilization

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Zhao, Yuejin; Yu, Fei; Zhu, Weiwen; Lang, Guanqing; Dong, Liquan

    2010-11-01

    This paper presents a novel fast block matching algorithm based on high-accuracy Gyro for steadying shaking image. It acquires motion vector from Gyro firstly. Then determines searching initial position and divides image motion into three modes of small, medium and large using the motion vector from Gyro. Finally, fast block matching algorithm is designed by improving four types of templates (square, diamond, hexagon, octagon). Experimental result shows that the algorithm can speed up 50% over common method (such as NTSS, FSS, DS) and maintain the same accuracy.

  2. Developing a portable gait cycle detection system using an inertial sensor and evaluating the accuracy of the gait cycle detection.

    PubMed

    Park, Min-Hwa; Kwak, Ki-Young; Kim, Dong-Wook

    2015-01-01

    Although researches had analyzed gait using small sensors, they analyzed only normal gaits. Thus, a research that can overcome the spatial limitations of the existing motion analyses and diagnose abnormal gaits for medical treatment is needed. Accordingly, this research developed the portable gait detection system that can detect gait using a gyroscope, and evaluated the accuracy of the system. The results showed an average recognition error rate of 1.7% for the normal and abnormal gaits, and confirmed that the gait cycle was detected with a high degree of accuracy. Using these characteristics, we could distinguish or diagnose, and treat, an abnormal gait.

  3. 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

  4. Accuracy and consistency of modern elastomeric pumps.

    PubMed

    Weisman, Robyn S; Missair, Andres; Pham, Phung; Gutierrez, Juan F; Gebhard, Ralf E

    2014-01-01

    Continuous peripheral nerve blockade has become a popular method of achieving postoperative analgesia for many surgical procedures. The safety and reliability of infusion pumps are dependent on their flow rate accuracy and consistency. Knowledge of pump rate profiles can help physicians determine which infusion pump is best suited for their clinical applications and specific patient population. Several studies have investigated the accuracy of portable infusion pumps. Using methodology similar to that used by Ilfeld et al, we investigated the accuracy and consistency of several current elastomeric pumps. PMID:25140510

  5. High accuracy calibration of the fiber spectroradiometer

    NASA Astrophysics Data System (ADS)

    Wu, Zhifeng; Dai, Caihong; Wang, Yanfei; Chen, Binhua

    2014-11-01

    Comparing to the big-size scanning spectroradiometer, the compact and convenient fiber spectroradiometer is widely used in various kinds of fields, such as the remote sensing, aerospace monitoring, and solar irradiance measurement. High accuracy calibration should be made before the use, which involves the wavelength accuracy, the background environment noise, the nonlinear effect, the bandwidth, the stray light and et al. The wavelength lamp and tungsten lamp are frequently used to calibration the fiber spectroradiometer. The wavelength difference can be easily reduced through the software or calculation. However, the nonlinear effect and the bandwidth always can affect the measurement accuracy significantly.

  6. High accuracy wall thickness loss monitoring

    NASA Astrophysics Data System (ADS)

    Gajdacsi, Attila; Cegla, Frederic

    2014-02-01

    Ultrasonic inspection of wall thickness in pipes is a standard technique applied widely in the petrochemical industry. The potential precision of repeat measurements with permanently installed ultrasonic sensors however significantly surpasses that of handheld sensors as uncertainties associated with coupling fluids and positional offsets are eliminated. With permanently installed sensors the precise evaluation of very small wall loss rates becomes feasible in a matter of hours. The improved accuracy and speed of wall loss rate measurements can be used to evaluate and develop more effective mitigation strategies. This paper presents an overview of factors causing variability in the ultrasonic measurements which are then systematically addressed and an experimental setup with the best achievable stability based on these considerations is presented. In the experimental setup galvanic corrosion is used to induce predictable and very small wall thickness loss. Furthermore, it is shown that the experimental measurements can be used to assess the effect of reduced wall loss that is produced by the injection of corrosion inhibitor. The measurements show an estimated standard deviation of about 20nm, which in turn allows us to evaluate the effect and behaviour of corrosion inhibitors within less than an hour.

  7. 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.

  8. Clinical Implications and Economic Impact of Accuracy Differences among Commercially Available Blood Glucose Monitoring Systems

    PubMed Central

    Budiman, Erwin S.; Samant, Navendu; Resch, Ansgar

    2013-01-01

    Background Despite accuracy standards, there are performance differences among commercially available blood glucose monitoring (BGM) systems. The objective of this analysis was to assess the potential clinical and economic impact of accuracy differences of various BGM systems using a modeling approach. Methods We simulated additional risk of hypoglycemia due to blood glucose (BG) measurement errors of five different BGM systems based on results of a real-world accuracy study, while retaining other sources of glycemic variability. Using data from published literature, we estimated an annual additional number of required medical interventions as a result of hypoglycemia. We based our calculations on patients with type 1 diabetes mellitus (T1DM) and T2DM requiring multiple daily injections (MDIs) of insulin in a U.S. health care system. We estimated additional costs attributable to treatment of severe hypoglycemic episodes resulting from BG measurement errors.. Results Results from our model predict an annual difference of approximately 296,000 severe hypoglycemic episodes from BG measurement errors for T1DM (105,000 for T2DM MDI) patients for the estimated U.S. population of 958,800 T1DM and 1,353,600 T2DM MDI patients, using the least accurate BGM system versus patients using the most accurate system in a U.S. health care system. This resulted in additional direct costs of approximately $339 million for T1DM and approximately $121 million for T2DM MDI patients per year. Conclusions Our analysis shows that error patterns over the operating range of BGM meter may lead to relevant clinical and economic outcome differences that may not be reflected in a common accuracy metric or standard. PMID:23566995

  9. Measuring the Accuracy of Diagnostic Systems.

    ERIC Educational Resources Information Center

    Swets, John A.

    1988-01-01

    Discusses the relative operating characteristic analysis of signal detection theory as a measure of diagnostic accuracy. Reports representative values of this measure in several fields. Compares how problems in these fields are handled. (CW)

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Vertical resolution and accuracy of atmospheric infrared sounding spectrometers

    NASA Technical Reports Server (NTRS)

    Huang, Hung-Lung; Smith, William L.; Woolf, Harold M.

    1992-01-01

    A theoretical analysis is performed to evaluate the accuracy and vertical resolution of atmospheric profiles obtained with the HIRS/2, GOES I/M, and HIS instruments. In addition, a linear simultaneous retrieval algorithm is used with aircraft observations to validate the theoretical predictions. Both theoretical and observational results clearly indicate that the accuracy and vertical resolution of the retrieval profile would be improved by high spectral resolution and broad spectral coverage of infrared radiance measurements. The HIS is found to possess the equivalent of 11 pieces of temperature- and 9 pieces of water vapor-independent precise measurements. The characteristics for temperature include a vertical resolution of 1-6 km with an accuracy of 1 K and for water vapor a vertical resolution of 0.5-3.0 km with an accuracy of 3 K in dewpoint temperature. The HIS is a factor of 2-3 times better in vertical resolution and a factor of 2 times better in accuracy than the GOES I/M and HIRS/2 filter radiometers.

  15. [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. PMID:27544966

  16. [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.

  17. Robust methods for assessing the accuracy of linear interpolated DEM

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Shi, Wenzhong; Liu, Eryong

    2015-02-01

    Methods for assessing the accuracy of a digital elevation model (DEM) with emphasis on robust methods have been studied in this paper. Based on the squared DEM residual population generated by the bi-linear interpolation method, three average-error statistics including (a) mean, (b) median, and (c) M-estimator are thoroughly investigated for measuring the interpolated DEM accuracy. Correspondingly, their confidence intervals are also constructed for each average error statistic to further evaluate the DEM quality. The first method mainly utilizes the student distribution while the second and third are derived from the robust theories. These innovative robust methods possess the capability of counteracting the outlier effects or even the skew distributed residuals in DEM accuracy assessment. Experimental studies using Monte Carlo simulation have commendably investigated the asymptotic convergence behavior of confidence intervals constructed by these three methods with the increase of sample size. It is demonstrated that the robust methods can produce more reliable DEM accuracy assessment results compared with those by the classical t-distribution-based method. Consequently, these proposed robust methods are strongly recommended for assessing DEM accuracy, particularly for those cases where the DEM residual population is evidently non-normal or heavily contaminated with outliers.

  18. Accuracy potentials for large space antenna structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1980-01-01

    The relationships among materials selection, truss design, and manufacturing techniques in the interest of surface accuracies for large space antennas are discussed. Among the antenna configurations considered are: tetrahedral truss, pretensioned truss, and geodesic dome and radial rib structures. Comparisons are made of the accuracy achievable by truss and dome structure types for a wide variety of diameters, focal lengths, and wavelength of radiated signal, taking into account such deforming influences as solar heating-caused thermal transients and thermal gradients.

  19. 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.

  20. Presynaptic Spontaneous Activity Enhances the Accuracy of Latency Coding.

    PubMed

    Levakova, Marie; Tamborrino, Massimiliano; Kostal, Lubomir; Lansky, Petr

    2016-10-01

    The time to the first spike after stimulus onset typically varies with the stimulation intensity. Experimental evidence suggests that neural systems use such response latency to encode information about the stimulus. We investigate the decoding accuracy of the latency code in relation to the level of noise in the form of presynaptic spontaneous activity. Paradoxically, the optimal performance is achieved at a nonzero level of noise and suprathreshold stimulus intensities. We argue that this phenomenon results from the influence of the spontaneous activity on the stabilization of the membrane potential in the absence of stimulation. The reported decoding accuracy improvement represents a novel manifestation of the noise-aided signal enhancement. PMID:27557098

  1. Presynaptic Spontaneous Activity Enhances the Accuracy of Latency Coding.

    PubMed

    Levakova, Marie; Tamborrino, Massimiliano; Kostal, Lubomir; Lansky, Petr

    2016-10-01

    The time to the first spike after stimulus onset typically varies with the stimulation intensity. Experimental evidence suggests that neural systems use such response latency to encode information about the stimulus. We investigate the decoding accuracy of the latency code in relation to the level of noise in the form of presynaptic spontaneous activity. Paradoxically, the optimal performance is achieved at a nonzero level of noise and suprathreshold stimulus intensities. We argue that this phenomenon results from the influence of the spontaneous activity on the stabilization of the membrane potential in the absence of stimulation. The reported decoding accuracy improvement represents a novel manifestation of the noise-aided signal enhancement.

  2. 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.

  3. Standardization of radon measurements. 2. Accuracy and proficiency testing

    SciTech Connect

    Matuszek, J.M.

    1990-01-01

    The accuracy of in situ environmental radon measurement techniques is reviewed and new data for charcoal canister, alpha-track (track-etch) and electret detectors are presented. Deficiencies reported at the 1987 meeting in Wurenlingen, Federal Republic of Germany, for measurements using charcoal detectors are confirmed by the new results. Accuracy and precision of the alpha-track measurements laboratory were better than in 1987. Electret detectors appear to provide a convenient, accurate, and precise system for the measurement of radon concentration. The need for a comprehensive, blind proficiency-testing programs is discussed.

  4. 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

  5. Interpersonal orientation and the accuracy of personality judgments.

    PubMed

    Vogt, Dawne S; Colvin, C Randall

    2003-04-01

    Are those who are more invested in developing and maintaining interpersonal relationships able to provide more accurate judgments of others' personality characteristics? Previous research has produced mixed findings. In the present study, a conceptual framework was presented and methods were used that overcome many of the problems encountered in past research on judgmental accuracy. On four occasions, 102 judges watched a 12-min videotaped dyadic interaction and described the personality of a designated target person. Judges' personality characteristics were described by self, parents, and friends. Results revealed that psychological communion was positively associated with judges' accuracy in rating targets' personality characteristics. In addition, whereas women were more communal and provided more accurate judgments than men, the relationship between communion and accuracy held after controlling for the effect of gender. Finally, preliminary findings suggested that interpersonally oriented individuals may sometimes draw on information about themselves and about stereotypical others to facilitate accurate judgments of others.

  6. Accuracy of genomic prediction using deregressed breeding values estimated from purebred and crossbred offspring phenotypes in pigs.

    PubMed

    Hidalgo, A M; Bastiaansen, J W M; Lopes, M S; Veroneze, R; Groenen, M A M; de Koning, D-J

    2015-07-01

    genetic merit of CB animals had zero to moderate predictive ability. We observed that the DGV accuracy of CB animals when training on PB data was greater than or equal to training on CB data. However, when results are corrected for the different levels of reliabilities in the PB and CB training data, we showed that training on CB data does outperform PB data for the prediction of CB genetic merit, indicating that more CB animals should be phenotyped to increase the reliability and, consequently, accuracy of DGV for CB genetic merit.

  7. 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...

  8. An improved method for determining force balance calibration accuracy

    NASA Astrophysics Data System (ADS)

    Ferris, Alice T.

    The results of an improved statistical method used at Langley Research Center for determining and stating the accuracy of a force balance calibration are presented. The application of the method for initial loads, initial load determination, auxiliary loads, primary loads, and proof loads is described. The data analysis is briefly addressed.

  9. 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.

  10. Surface accuracy measurement sensor for deployable reflector antennas

    NASA Technical Reports Server (NTRS)

    Spiers, R. B., Jr.

    1981-01-01

    The breadboard surface accuracy measurement sensor is an optical angle sensor which provides continuous line of sight position measurements of infrared source targets placed strategically about the antenna surface. Measurements of target coordinates define the surface figure relative to a reference frame on the antenna. Sensor operation, tests and test results to date are described.

  11. 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…

  12. Accuracies of diagnostic methods for acute appendicitis.

    PubMed

    Park, Jong Seob; Jeong, Jin Ho; Lee, Jong In; Lee, Jong Hoon; Park, Jea Kun; Moon, Hyoun Jong

    2013-01-01

    The objectives were to evaluate the effectiveness of ultrasonography, computed tomography, and physical examination for diagnosing acute appendicitis with analyzing their accuracies and negative appendectomy rates in a clinical rather than research setting. A total of 2763 subjects were enrolled. Sensitivity, specificity, positive predictive value, and negative predictive value and negative appendectomy rate for ultrasonography, computed tomography, and physical examination were calculated. Confirmed positive acute appendicitis was defined based on pathologic findings, and confirmed negative acute appendicitis was defined by pathologic findings as well as on clinical follow-up. Sensitivity, specificity, positive predictive value, and negative predictive value for ultrasonography were 99.1, 91.7, 96.5, and 97.7 per cent, respectively; for computed tomography, 96.4, 95.4, 95.6, and 96.3 per cent, respectively; and for physical examination, 99.0, 76.1, 88.1, and 97.6 per cent, respectively. The negative appendectomy rate was 5.8 per cent (5.2% in the ultrasonography group, 4.3% in the computed tomography group, and 12.2% in the physical examination group). Ultrasonography/computed tomography should be performed routinely for diagnosis of acute appendicitis. However, in view of its advantages, ultrasonography should be performed first. Also, if the result of a physical examination is negative, imaging studies after physical examination can be unnecessary.

  13. 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.

  14. 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.

  15. 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.

  16. Accuracy of Lagrange-sinc functions as a basis set for electronic structure calculations of atoms and molecules.

    PubMed

    Choi, Sunghwan; Hong, Kwangwoo; Kim, Jaewook; Kim, Woo Youn

    2015-03-01

    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.

  17. 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. PMID:24988539

  18. 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

  19. 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

  20. 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

  1. Criteria for the accuracy of small polaron quantum master equation in simulating excitation energy transfer dynamics

    SciTech Connect

    Chang, Hung-Tzu; Cheng, Yuan-Chung; Zhang, Pan-Pan

    2013-12-14

    The small polaron quantum master equation (SPQME) proposed by Jang et al. [J. Chem. Phys. 129, 101104 (2008)] is a promising approach to describe coherent excitation energy transfer dynamics in complex molecular systems. To determine the applicable regime of the SPQME approach, we perform a comprehensive investigation of its accuracy by comparing its simulated population dynamics with numerically exact quasi-adiabatic path integral calculations. We demonstrate that the SPQME method yields accurate dynamics in a wide parameter range. Furthermore, our results show that the accuracy of polaron theory depends strongly upon the degree of exciton delocalization and timescale of polaron formation. Finally, we propose a simple criterion to assess the applicability of the SPQME theory that ensures the reliability of practical simulations of energy transfer dynamics with SPQME in light-harvesting systems.

  2. 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.

  3. 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%.

  4. Ab Initio Calculation of Rate Constants for Molecule-Surface Reactions with Chemical Accuracy.

    PubMed

    Piccini, GiovanniMaria; Alessio, Maristella; Sauer, Joachim

    2016-04-18

    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).

  5. Influence of measurement accuracy on the application of the 1991 NIOSH equation.

    PubMed

    Dempsey, P G; Burdorf, A; Fathallah, F A; Sorock, G S; Hashemi, L

    2001-02-01

    A relatively neglected topic in manual materials handling (MMH) research is the impact of the accuracy of task parameter measurements on the application of various assessment methods. A laboratory experiment was conducted to investigate the accuracy of NIOSH equation parameter measurements made by eight subjects following a 4-h training session. Five individual tasks were measured; two were single tasks and three were part of a multiple-component simulated palletizing operation. Significant differences between reference parameter measurements and average measurements made by subjects were found. The sensitivity analysis showed that frequency and horizontal location are the most important parameters. These parameters also tended to have the highest measurement errors. Recommendations for increasing the effectiveness of training programs for NIOSH equation users based on the results of the study are presented. PMID:11209836

  6. 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.

  7. Lens distortion elimination for improving measurement accuracy of fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Li, Kai; Bu, Jingjie; Zhang, Dongsheng

    2016-10-01

    Fringe projection profilometry (FPP) is a powerful method for three-dimensional (3D) shape measurement. However, the measurement accuracy of the existing FPP is often hindered by the distortion of the lens used in FPP. In this paper, a simple and efficient method is presented to overcome this problem. First, the FPP system is calibrated as a stereovision system. Then, the camera lens distortion is eliminated by correcting the captured images. For the projector lens distortion, distorted fringe patterns are generated according to the lens distortion model. With these distorted fringe patterns, the projector can project undistorted fringe patterns, which means that the projector lens distortion is eliminated. Experimental results show that the proposed method can successfully eliminate the lens distortions of FPP and therefore improves its measurement accuracy.

  8. Volume of the Human Septal Forebrain Region Is a Predictor of Source Memory Accuracy

    PubMed Central

    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 highlight the need for additional research into the role of septal nuclei in memory and other impairments associated with human diseases. PMID:22152217

  9. 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

  10. 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

  11. 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

  12. 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.

  13. Adaptive Mesh Refinement for High Accuracy Wall Loss Determination in Accelerating Cavity Design

    SciTech Connect

    Ge, L

    2004-06-14

    This paper presents the improvement in wall loss determination when adaptive mesh refinement (AMR) methods are used with the parallel finite element eigensolver Omega3P. We show that significant reduction in the number of degrees of freedom (DOFs) as well as a faster rate of convergence can be achieved as compared with results from uniform mesh refinement in determining cavity wall loss to a desired accuracy. Test cases for which measurements are available will be examined, and comparison with uniform refinement results will be discussed.

  14. 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.

  15. Effect of concurrent oxygen therapy on accuracy of forecasting imminent postoperative desaturation.

    PubMed

    ElMoaqet, Hisham; Tilbury, Dawn M; Ramachandran, Satya Krishna

    2015-08-01

    Episodic postoperative desaturation occurs predominantly from respiratory depression or airway obstruction. Monitor display of desaturation is typically delayed by over 30 s after these dynamic inciting events, due to perfusion delays, signal capture and averaging. Prediction of imminent critical desaturation could aid development of dynamic high-fidelity response systems that reduce or prevent the inciting event from occurring. Oxygen therapy is known to influence the depth and duration of desaturation epochs, thereby potentially influencing the accuracy of forecasting of desaturation. In this study, postoperative pulse oximetry data were retrospectively modeled using autoregressive methods to create prediction models for [Formula: see text] and imminent critical desaturation in the postoperative period. The accuracy of these models in predicting near future [Formula: see text] values was tested using root mean square error. The model accuracy for prediction of critical desaturation ([Formula: see text] [Formula: see text]) was evaluated using meta-analytical methods (sensitivity, specificity, likelihood ratios, diagnostic odds ratios and area under summary receiver operating characteristic curves). Between-study heterogeneity was used as a measure of reliability of the model across different patients and evaluated using the tau-squared statistic. Model performance was evaluated in [Formula: see text] patients who received postoperative oxygen supplementation and [Formula: see text] patients who did not receive oxygen. Our results show that model accuracy was high with root mean square errors between 0.2 and 2.8%. Prediction accuracy as defined by area under the curve for critical desaturation events was observed to be greater in patients receiving oxygen in the 60-s horizon ([Formula: see text] vs. [Formula: see text]). This was likely related to the higher frequency of events in this group (median [IQR] [Formula: see text] [Formula: see text]) than patients who

  16. 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.

  17. Diagnostic Accuracy of Xpert Test in Tuberculosis Detection: A Systematic Review and Meta-analysis

    PubMed Central

    Kaur, Ravdeep; Kachroo, Kavita; Sharma, Jitendar Kumar; Vatturi, Satyanarayana Murthy; Dang, Amit

    2016-01-01

    Background: World Health Organization (WHO) recommends the use of Xpert MTB/RIF assay for rapid diagnosis of tuberculosis (TB) and detection of rifampicin resistance. This systematic review was done to know about the diagnostic accuracy and cost-effectiveness of the Xpert MTB/RIF assay. Methods: A systematic literature search was conducted in following databases: Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, MEDLINE, PUBMED, Scopus, Science Direct and Google Scholar for relevant studies for studies published between 2010 and December 2014. Studies given in the systematic reviews were accessed separately and used for analysis. Selection of studies, data extraction and assessment of quality of included studies was performed independently by two reviewers. Studies evaluating the diagnostic accuracy of Xpert MTB/RIF assay among adult or predominantly adult patients (≥14 years), presumed to have pulmonary TB with or without HIV infection were included in the review. Also, studies that had assessed the diagnostic accuracy of Xpert MTB/RIF assay using sputum and other respiratory specimens were included. Results: The included studies had a low risk of any form of bias, showing that findings are of high scientific validity and credibility. Quantitative analysis of 37 included studies shows that Xpert MTB/RIF is an accurate diagnostic test for TB and detection of rifampicin resistance. Conclusion: Xpert MTB/RIF assay is a robust, sensitive and specific test for accurate diagnosis of tuberculosis as compared to conventional tests like culture and microscopic examination. PMID:27013842

  18. 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.

  19. 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.

  20. 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.