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Sample records for micro-arcsecond accuracy level

  1. THE MICRO-ARCSECOND SCINTILLATION-INDUCED VARIABILITY (MASIV) SURVEY. III. OPTICAL IDENTIFICATIONS AND NEW REDSHIFTS

    Energy Technology Data Exchange (ETDEWEB)

    Pursimo, Tapio [Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma (Spain); Ojha, Roopesh [NVI Inc./U. S. Naval Observatory, 3450 Massachusetts Ave NW, Washington DC (United States); Jauncey, David L. [CSIRO Astronomy and Space Science and Mount Stromlo Observatory, Canberra ACT 0200 (Australia); Rickett, Barney J. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Dutka, Michael S. [The Catholic University of America, 620 Michigan Ave., N.E., Washington DC 20064 (United States); Koay, Jun Yi; Bignall, Hayley E.; Macquart, Jean-Pierre [ICRAR, Curtin University, Bentley, WA 6845 (Australia); Lovell, James E. J. [School of Mathematics and Physics, University of Tasmania, TAS 7001 (Australia); Kedziora-Chudczer, Lucyna, E-mail: tpursimo@not.iac.es [School of Physics and Astrophysics, UNSW, Sydney NSW 2052 (Australia)

    2013-04-10

    Intraday variability (IDV) of the radio emission from active galactic nuclei is now known to be predominantly due to interstellar scintillation (ISS). The MASIV (The Micro-Arcsecond Scintillation-Induced Variability) survey of 443 flat spectrum sources revealed that the IDV is related to the radio flux density and redshift. A study of the physical properties of these sources has been severely handicapped by the absence of reliable redshift measurements for many of these objects. This paper presents 79 new redshifts and a critical evaluation of 233 redshifts obtained from the literature. We classify spectroscopic identifications based on emission line properties, finding that 78% of the sources have broad emission lines and are mainly FSRQs. About 16% are weak lined objects, chiefly BL Lacs, and the remaining 6% are narrow line objects. The gross properties (redshift, spectroscopic class) of the MASIV sample are similar to those of other blazar surveys. However, the extreme compactness implied by ISS favors FSRQs and BL Lacs in the MASIV sample as these are the most compact object classes. We confirm that the level of IDV depends on the 5 GHz flux density for all optical spectral types. We find that BL Lac objects tend to be more variable than broad line quasars. The level of ISS decreases substantially above a redshift of about two. The decrease is found to be generally consistent with ISS expected for beamed emission from a jet that is limited to a fixed maximum brightness temperature in the source rest frame.

  2. The MAXIM Pathfinder Mission: X-Ray Imaging at 100 Micro-Arcseconds

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    Cash, Webster; White, Nick; Joy, Marshall

    2000-01-01

    We present the results of a study to show how it is possible to build a super high resolution x-ray imaging mission based on the principles of x-ray interferometry. The mission concept uses today's technology to specify a 1.4 meter baseline interferometer that will resolve features as fine as 100 micro-arcsecond imaging at 1keV. This resolution is sufficient to produce high quality images of the coronae of other stars.

  3. Micro-arcsecond Celestial Reference Frames: definition and realization — Impact of the recent IAU Resolutions

    International Nuclear Information System (INIS)

    Capitaine, Nicole

    2012-01-01

    improvements in the fields of astrometry, celestial mechanics, geodynamics, geodesy, etc. Of special interest are the improvements in the model for variations in Earth's rotation, which, in turn, can provide better knowledge of the dynamics of the Earth's interior. These have also contributed to a significant improvement in the accuracy of the ephemerides of the solar system bodies as determined from modern measurements, with a large number of scientific applications. This paper recalls the main aspects of the recent IAU resolutions on reference systems as well as their consequences on the concepts, definitions, nomenclature and models that are suitable for the definition, realization and transformation of reference frames at a microarcsecond level.

  4. Multi-Accuracy-Level Burning Plasma Simulations

    International Nuclear Information System (INIS)

    Artaud, J. F.; Basiuk, V.; Garcia, J.; Giruzzi, G.; Huynh, P.; Huysmans, G.; Imbeaux, F.; Johner, J.; Scheider, M.

    2007-01-01

    The design of a reactor grade tokamak is based on a hierarchy of tools. We present here three codes that are presently used for the simulations of burning plasmas. At the first level there is a 0-dimensional code that allows to choose a reasonable range of global parameters; in our case the HELIOS code was used for this task. For the second level we have developed a mixed 0-D / 1-D code called METIS that allows to study the main properties of a burning plasma, including profiles and all heat and current sources, but always under the constraint of energy and other empirical scaling laws. METIS is a fast code that permits to perform a large number of runs (a run takes about one minute) and design the main features of a scenario, or validate the results of the 0-D code on a full time evolution. At the top level, we used the full 1D1/2 suite of codes CRONOS that gives access to a detailed study of the plasma profiles evolution. CRONOS can use a variety of modules for source terms and transport coefficients computation with different level of complexity and accuracy: from simple estimators to highly sophisticated physics calculations. Thus it is possible to vary the accuracy of burning plasma simulations, as a trade-off with computation time. A wide range of scenario studies can thus be made with CRONOS and then validated with post-processing tools like MHD stability analysis. We will present in this paper results of this multi-level analysis applied to the ITER hybrid scenario. This specific example will illustrate the importance of having several tools for the study of burning plasma scenarios, especially in a domain that present devices cannot access experimentally. (Author)

  5. Diagnostic accuracy of routine blood examinations and CSF lactate level for post-neurosurgical bacterial meningitis

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    Yang Zhang

    2017-06-01

    Conclusions: The PBM diagnostic accuracy of routine blood examinations was relatively low, whereas the accuracy of CSF lactate level was high. Some variables that are involved in the incidence of PBM can also affect the diagnostic accuracy for PBM. Taking into account the effects of these variables significantly improves the diagnostic accuracies of routine blood examinations and CSF lactate level.

  6. Performance of modern tide gauges: towards mm-level accuracy

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    Belén Martín Míguez

    2012-09-01

    Full Text Available Considerable efforts are being made worldwide to upgrade tide gauge networks using new technologies. Because of the unique location of the Kerguelen Islands, the measurement of sea level there has received particular attention, with up to four systems equipped with modern sensors functioning simultaneously (two pressure tide gauges, a radar tide gauge, and a GPS-equipped buoy. We analysed and compared the sea level data obtained with these systems from 2003 to 2010, together with a time series of tide pole observations. This is the first time that a multi-comparison study with tide gauges has been undertaken over such a long time span and that the stability of modern radar tide gauges has been examined. The multi-comparison enabled us to evaluate the performance of the tide gauges in several frequency ranges, identify errors and estimate their magnitude. The drift of the pressure sensors (up to 8.0 mm/yr was found to be one of the most relevant sources of systematic error. Other sources of difference such as clock drift, scale error and different locations of the instruments were also detected. After correcting the time series of sea level for these errors we estimated an upper bound for the radar instrumental error in field condition at ~0.3 cm.

  7. Diagnostic accuracy of routine blood examinations and CSF lactate level for post-neurosurgical bacterial meningitis.

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    Zhang, Yang; Xiao, Xiong; Zhang, Junting; Gao, Zhixian; Ji, Nan; Zhang, Liwei

    2017-06-01

    To evaluate the diagnostic accuracy of routine blood examinations and Cerebrospinal Fluid (CSF) lactate level for Post-neurosurgical Bacterial Meningitis (PBM) at a large sample-size of post-neurosurgical patients. The diagnostic accuracies of routine blood examinations and CSF lactate level to distinguish between PAM and PBM were evaluated with the values of the Area Under the Curve of the Receiver Operating Characteristic (AUC -ROC ) by retrospectively analyzing the datasets of post-neurosurgical patients in the clinical information databases. The diagnostic accuracy of routine blood examinations was relatively low (AUC -ROC CSF lactate level achieved rather high diagnostic accuracy (AUC -ROC =0.891; CI 95%, 0.852-0.922). The variables of patient age, operation duration, surgical diagnosis and postoperative days (the interval days between the neurosurgery and examinations) were shown to affect the diagnostic accuracy of these examinations. The variables were integrated with routine blood examinations and CSF lactate level by Fisher discriminant analysis to improve their diagnostic accuracy. As a result, the diagnostic accuracy of blood examinations and CSF lactate level was significantly improved with an AUC -ROC value=0.760 (CI 95%, 0.737-0.782) and 0.921 (CI 95%, 0.887-0.948) respectively. The PBM diagnostic accuracy of routine blood examinations was relatively low, whereas the accuracy of CSF lactate level was high. Some variables that are involved in the incidence of PBM can also affect the diagnostic accuracy for PBM. Taking into account the effects of these variables significantly improves the diagnostic accuracies of routine blood examinations and CSF lactate level. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Evaluation of Low-Cost, Centimeter-Level Accuracy OEM GNSS Receivers

    Science.gov (United States)

    2018-02-02

    This report discusses the results of a study to quantify the performance of low-cost, centimeter-level accurate Global Navigation Satellite Systems (GNSS) receivers that have appeared on the market in the last few years. Centimeter-level accuracy is ...

  9. Recommended aerobic fitness level for metabolic health in children and adolescents: a study of diagnostic accuracy

    DEFF Research Database (Denmark)

    Adegboye, Amanda Ra; Anderssen, Sigmund A; Froberg, Karsten

    2011-01-01

    Objective To define the optimal cut-off for low aerobic fitness and to evaluate its accuracy to predict clustering of risk factors for cardiovascular disease in children and adolescents. Design Study of diagnostic accuracy using a cross-sectional database. Setting European Youth Heart Study...... would be expected by chance (AUC >0.5) for all cut-offs. Conclusions Aerobic fitness is easy to measure, and is an accurate tool for screening children with clustering of cardiovascular risk factors. Promoting physical activity in children with aerobic fitness level lower than the suggested cut...

  10. A design of optical modulation system with pixel-level modulation accuracy

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    Zheng, Shiwei; Qu, Xinghua; Feng, Wei; Liang, Baoqiu

    2018-01-01

    Vision measurement has been widely used in the field of dimensional measurement and surface metrology. However, traditional methods of vision measurement have many limits such as low dynamic range and poor reconfigurability. The optical modulation system before image formation has the advantage of high dynamic range, high accuracy and more flexibility, and the modulation accuracy is the key parameter which determines the accuracy and effectiveness of optical modulation system. In this paper, an optical modulation system with pixel level accuracy is designed and built based on multi-points reflective imaging theory and digital micromirror device (DMD). The system consisted of digital micromirror device, CCD camera and lens. Firstly we achieved accurate pixel-to-pixel correspondence between the DMD mirrors and the CCD pixels by moire fringe and an image processing of sampling and interpolation. Then we built three coordinate systems and calculated the mathematic relationship between the coordinate of digital micro-mirror and CCD pixels using a checkerboard pattern. A verification experiment proves that the correspondence error is less than 0.5 pixel. The results show that the modulation accuracy of system meets the requirements of modulation. Furthermore, the high reflecting edge of a metal circular piece can be detected using the system, which proves the effectiveness of the optical modulation system.

  11. A measurement control program to meet desired levels of precision and accuracy

    International Nuclear Information System (INIS)

    Bruckner, L.A.

    1991-01-01

    Measurement control programs are usually designed to test for precision and accuracy. Many instruments, however, display non-random data patterns such as biases or seasonal variations which are statistically significant but are of no practical significance. Application of the usual statistical tests can cause these instruments to be removed from service unnecessarily. It is tempting to try to overcome this problem by frequently adjusting the instrument or by arbitrarily changing the parameters of the statistical tests so that failures occur less often. This, of course invalidates the statistical tests. In the author's opinion, the correct way to handle this problem is to identify the desired levels of precision and accuracy, and then to combine these levels with valid statistical techniques in the measurement control-program. This paper describes one way to accomplish this

  12. Improving the accuracy of acetabular cup implantation using a bulls-eye spirit level.

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    Macdonald, Duncan; Gupta, Sanjay; Ohly, Nicholas E; Patil, Sanjeev; Meek, R; Mohammed, Aslam

    2011-01-01

    Acetabular introducers have a built-in inclination of 45 degrees to the handle shaft. With patients in the lateral position, surgeons aim to align the introducer shaft vertical to the floor to implant the acetabulum at 45 degrees. We aimed to determine if a bulls-eye spirit level attached to an introducer improved the accuracy of implantation. A small circular bulls-eye spirit level was attached to the handle of an acetabular introducer. A saw bone hemipelvis was fixed to a horizontal, flat surface. A cement substitute was placed in the acetabulum and subjects were asked to implant a polyethylene cup, aiming to obtain an angle of inclination of 45 degrees. Two attempts were made with the spirit level masked and two with it unmasked. The distance of the air bubble from the spirit level's center was recorded by a single assessor. The angle of inclination of the acetabular component was then calculated. Subjects included both orthopedic consultants and trainees. Twenty-five subjects completed the study. Accuracy of acetabular implantation when using the unmasked spirit level improved significantly in all grades of surgeon. With the spirit level masked, 12 out of 50 attempts were accurate at 45 degrees inclination; 11 out of 50 attempts were "open," with greater than 45 degrees of inclination, and 27 were "closed," with less than 45 degrees. With the spirit level visible, all subjects achieved an inclination angle of exactly 45 degrees. A simple device attached to the handle of an acetabular introducer can significantly improve the accuracy of implantation of a cemented cup into a saw bone pelvis in the lateral position.

  13. Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

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    Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

    2012-03-01

    Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

  14. Accuracy of different abutment level impression techniques in All-On-4 dental implants

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    Marzieh Alikhasi

    2012-01-01

    Full Text Available Background and Aims: Passive fit of prosthetic frameworks is a major concern in implant dentistry. Impression technique is one of the several variables that may affect the outcome of dental implants. The purpose of this study was to compare the three dimensional accuracy of direct and indirect abutment level implant impressions ofALL-ON-4 treatment plan.Materials and Methods: A reference acrylic resin model with four Branemark fixtures was made according to All-On-4 treatment plan. Multiunit abutments were screwed into the fixtures and two special trays were made for direct and indirect impression techniques. Ten direct and ten indirect impression techniques with respective impression transfers were made. Impressions were poured with stone and the positional accuracy of the abutment analogues in each dimension of x, y, and z axes and also angular displacement (Δθ were evaluated using a Coordinate Measuring Machine (CMM. Data were analyzed using T- test.Results: The results showed that direct impression technique was significantly more accurate than indirect technique (P<0.001.Conclusion: The results showed that the accuracy of direct impression technique was significantly more than that of indirect technique in Δθ and Δr coordinate and also Δx, Δy, Δz.

  15. Dual cesium and rubidium atomic fountain with a 10-16 level accuracy and applications

    International Nuclear Information System (INIS)

    Chapelet, F.

    2008-05-01

    Atomic fountains are the most accomplished development of the atomic clocks based on the cesium atom whose hyperfine resonance defines the SI second since 1967. Today these systems are among those which realize the second with the best accuracy. We present the last developments of the cold cesium and rubidium atom dual fountain experiment at LNE-SYRTE. This unique dual setup would allow to obtain an outstanding resolution in fundamental physics tests based on atomic transition frequency comparisons. In order to enable operation with both atomic species simultaneously, we designed, tested and implemented on the fountain new collimators which combine the laser lights corresponding to each atom. By comparing our rubidium fountain to another cesium fountain over a decade, we performed a test of the stability of the fine structure constant at the level of 5 * 10 -16 per year. We carried on the work on the clock accuracy and we focused on the phase gradients effects in the interrogation cavity and on the microwave leakage. The fountain accuracy has been evaluated to 4 * 10 -16 for the cesium clock and to 5 * 10 -16 for the refurbished rubidium clock. As a powerful instrument of metrology, our fountain was implicated in many clock comparisons and contributed many times to calibrate the International Atomic Time. Furthermore, we used the fountain to perform a new test of Lorentz local invariance. (author)

  16. A Study of Light Level Effect on the Accuracy of Image Processing-based Tomato Grading

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    Prijatna, D.; Muhaemin, M.; Wulandari, R. P.; Herwanto, T.; Saukat, M.; Sugandi, W. K.

    2018-05-01

    Image processing method has been used in non-destructive tests of agricultural products. Compared to manual method, image processing method may produce more objective and consistent results. Image capturing box installed in currently used tomato grading machine (TEP-4) is equipped with four fluorescence lamps to illuminate the processed tomatoes. Since the performance of any lamp will decrease if its service time has exceeded its lifetime, it is predicted that this will affect tomato classification. The objective of this study was to determine the minimum light levels which affect classification accuracy. This study was conducted by varying light level from minimum and maximum on tomatoes in image capturing boxes and then investigates its effects on image characteristics. Research results showed that light intensity affects two variables which are important for classification, for example, area and color of captured image. Image processing program was able to determine correctly the weight and classification of tomatoes when light level was 30 lx to 140 lx.

  17. Age accuracy and resolution of Quaternary corals used as proxies for sea level

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    Edinger, E. N.; Burr, G. S.; Pandolfi, J. M.; Ortiz, J. C.

    2007-01-01

    The accuracy of global eustatic sea level curves measured from raised Quaternary reefs, using radiometric ages of corals at known heights, may be limited by time-averaging, which affects the variation in coral age at a given height. Time-averaging was assessed in uplifted Holocene reef sequences from the Huon Peninsula, Papua New Guinea, using radiocarbon dating of coral skeletons in both horizontal transects and vertical sequences. Calibrated 2σ age ranges varied from 800 to 1060 years along horizontal transects, but weighted mean ages calculated from 15-18 dates per horizon were accurate to a resolution within 154-214 yr. Approximately 40% of the variability in age estimate resulted from internal variability inherent to 14C estimates, and 60% was due to time-averaging. The accuracy of age estimates of sea level change in studies using single dated corals as proxies for sea level is probably within 1000 yr of actual age, but can be resolved to ≤ 250 yr if supported by dates from analysis of a statistical population of corals at each stratigraphic interval. The range of time-averaging among reef corals was much less than that for shelly benthos. Ecological time-averaging dominated over sedimentological time averaging for reef corals, opposite to patterns reported from shelly benthos in siliciclastic environments.

  18. Effects of impression levels and trays on the accuracy of impressions taken from angulated implants.

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    Geramipanah, Farideh; Sahebi, Majid; Davari, Maryam; Hajimahmoudi, Mohammadreza; Rakhshan, Vahid

    2015-09-01

    It is crucial to keep the misfit of the abutment-fixture unit at the lowest possible rate. There are a few controversial studies on the accuracy of impression making of angulated implants, and much fewer (and controversial) studies on the abutment-level impression technique, which is a convenient and clinically favorable method. Besides, there are no studies on comparison of sectional vs. full-arch trays. We aimed to assess these. A trapezoidal model with four angulated implants installed at 20° and 30° buccal tilts was fabricated. Forty impressions were taken from this model, with two groups of full-arch and sectional custom trays (n = 2 × 20), each divided into two subgroups of implant-level and abutment-level techniques (n = 2 × 2 × 10 in four subgroups). Absolute and non-absolute linear and angular impression errors were estimated by comparing the fabricated casts with the model, using a coordinate measuring machine. The effects of sectional/full-arch trays and abutment-level and fixture-level techniques on impression accuracies were analyzed using one- and two-way analyses of variance (ANOVA), Tukey, Mann-Whitney, and one-sample t-tests (α = 0.05, Mann-Whitney's α using the Bonferroni Bonferroni method). No significant differences between the absolute linear errors of the two trays (P = 0.100 [ANOVA]) and the two levels (P = 0.400 [ANOVA]) were observed. The assessment of absolute angular errors showed no significant differences (all P values ≥ 0.4 [ANOVA]). The difference between the linear errors in the full-arch vs. sectional trays was not significant in the fixture-level group (P = 0.290). However, in the abutment-level group, the linear error was significantly greater in the sectional tray compared to full-arch tray (P = 0.013, α = 0.025 [Mann-Whitney]). Using sectional trays might not be advantageous over full-arch trays. Sectional trays are not recommended for taking abutment-level impressions. The abutment-level

  19. Enhancing spatial detection accuracy for syndromic surveillance with street level incidence data

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    Alemi Farrokh

    2010-01-01

    Full Text Available Abstract Background The Department of Defense Military Health System operates a syndromic surveillance system that monitors medical records at more than 450 non-combat Military Treatment Facilities (MTF worldwide. The Electronic Surveillance System for Early Notification of Community-based Epidemics (ESSENCE uses both temporal and spatial algorithms to detect disease outbreaks. This study focuses on spatial detection and attempts to improve the effectiveness of the ESSENCE implementation of the spatial scan statistic by increasing the spatial resolution of incidence data from zip codes to street address level. Methods Influenza-Like Illness (ILI was used as a test syndrome to develop methods to improve the spatial accuracy of detected alerts. Simulated incident clusters of various sizes were superimposed on real ILI incidents from the 2008/2009 influenza season. Clusters were detected using the spatial scan statistic and their displacement from simulated loci was measured. Detected cluster size distributions were also evaluated for compliance with simulated cluster sizes. Results Relative to the ESSENCE zip code based method, clusters detected using street level incidents were displaced on average 65% less for 2 and 5 mile radius clusters and 31% less for 10 mile radius clusters. Detected cluster size distributions for the street address method were quasi normal and sizes tended to slightly exceed simulated radii. ESSENCE methods yielded fragmented distributions and had high rates of zero radius and oversized clusters. Conclusions Spatial detection accuracy improved notably with regard to both location and size when incidents were geocoded to street addresses rather than zip code centroids. Since street address geocoding success rates were only 73.5%, zip codes were still used for more than one quarter of ILI cases. Thus, further advances in spatial detection accuracy are dependant on systematic improvements in the collection of individual

  20. A High-Throughput, High-Accuracy System-Level Simulation Framework for System on Chips

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    Guanyi Sun

    2011-01-01

    Full Text Available Today's System-on-Chips (SoCs design is extremely challenging because it involves complicated design tradeoffs and heterogeneous design expertise. To explore the large solution space, system architects have to rely on system-level simulators to identify an optimized SoC architecture. In this paper, we propose a system-level simulation framework, System Performance Simulation Implementation Mechanism, or SPSIM. Based on SystemC TLM2.0, the framework consists of an executable SoC model, a simulation tool chain, and a modeling methodology. Compared with the large body of existing research in this area, this work is aimed at delivering a high simulation throughput and, at the same time, guaranteeing a high accuracy on real industrial applications. Integrating the leading TLM techniques, our simulator can attain a simulation speed that is not slower than that of the hardware execution by a factor of 35 on a set of real-world applications. SPSIM incorporates effective timing models, which can achieve a high accuracy after hardware-based calibration. Experimental results on a set of mobile applications proved that the difference between the simulated and measured results of timing performance is within 10%, which in the past can only be attained by cycle-accurate models.

  1. Overview of Akatsuki data products: definition of data levels, method and accuracy of geometric correction

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    Ogohara, Kazunori; Takagi, Masahiro; Murakami, Shin-ya; Horinouchi, Takeshi; Yamada, Manabu; Kouyama, Toru; Hashimoto, George L.; Imamura, Takeshi; Yamamoto, Yukio; Kashimura, Hiroki; Hirata, Naru; Sato, Naoki; Yamazaki, Atsushi; Satoh, Takehiko; Iwagami, Naomoto; Taguchi, Makoto; Watanabe, Shigeto; Sato, Takao M.; Ohtsuki, Shoko; Fukuhara, Tetsuya; Futaguchi, Masahiko; Sakanoi, Takeshi; Kameda, Shingo; Sugiyama, Ko-ichiro; Ando, Hiroki; Lee, Yeon Joo; Nakamura, Masato; Suzuki, Makoto; Hirose, Chikako; Ishii, Nobuaki; Abe, Takumi

    2017-12-01

    We provide an overview of data products from observations by the Japanese Venus Climate Orbiter, Akatsuki, and describe the definition and content of each data-processing level. Levels 1 and 2 consist of non-calibrated and calibrated radiance (or brightness temperature), respectively, as well as geometry information (e.g., illumination angles). Level 3 data are global-grid data in the regular longitude-latitude coordinate system, produced from the contents of Level 2. Non-negligible errors in navigational data and instrumental alignment can result in serious errors in the geometry calculations. Such errors cause mismapping of the data and lead to inconsistencies between radiances and illumination angles, along with errors in cloud-motion vectors. Thus, we carefully correct the boresight pointing of each camera by fitting an ellipse to the observed Venusian limb to provide improved longitude-latitude maps for Level 3 products, if possible. The accuracy of the pointing correction is also estimated statistically by simulating observed limb distributions. The results show that our algorithm successfully corrects instrumental pointing and will enable a variety of studies on the Venusian atmosphere using Akatsuki data.[Figure not available: see fulltext.

  2. Nano-level instrumentation for analyzing the dynamic accuracy of a rolling element bearing

    International Nuclear Information System (INIS)

    Yang, Z.; Hong, J.; Zhang, J.; Wang, M. Y.; Zhu, Y.

    2013-01-01

    The rotational performance of high-precision rolling bearings is fundamental to the overall accuracy of complex mechanical systems. A nano-level instrument to analyze rotational accuracy of high-precision bearings of machine tools under working conditions was developed. In this instrument, a high-precision (error motion < 0.15 μm) and high-stiffness (2600 N axial loading capacity) aerostatic spindle was applied to spin the test bearing. Operating conditions could be simulated effectively because of the large axial loading capacity. An air-cylinder, controlled by a proportional pressure regulator, was applied to drive an air-bearing subjected to non-contact and precise loaded axial forces. The measurement results on axial loading and rotation constraint with five remaining degrees of freedom were completely unconstrained and uninfluenced by the instrument's structure. Dual capacity displacement sensors with 10 nm resolution were applied to measure the error motion of the spindle using a double-probe error separation method. This enabled the separation of the spindle's error motion from the measurement results of the test bearing which were measured using two orthogonal laser displacement sensors with 5 nm resolution. Finally, a Lissajous figure was used to evaluate the non-repetitive run-out (NRRO) of the bearing at different axial forces and speeds. The measurement results at various axial loadings and speeds showed the standard deviations of the measurements’ repeatability and accuracy were less than 1% and 2%. Future studies will analyze the relationship between geometrical errors and NRRO, such as the ball diameter differences of and the geometrical errors in the grooves of rings

  3. Improving Accuracy and Simplifying Training in Fingerprinting-Based Indoor Location Algorithms at Room Level

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    Mario Muñoz-Organero

    2016-01-01

    Full Text Available Fingerprinting-based algorithms are popular in indoor location systems based on mobile devices. Comparing the RSSI (Received Signal Strength Indicator from different radio wave transmitters, such as Wi-Fi access points, with prerecorded fingerprints from located points (using different artificial intelligence algorithms, fingerprinting-based systems can locate unknown points with a few meters resolution. However, training the system with already located fingerprints tends to be an expensive task both in time and in resources, especially if large areas are to be considered. Moreover, the decision algorithms tend to be of high memory and CPU consuming in such cases and so does the required time for obtaining the estimated location for a new fingerprint. In this paper, we study, propose, and validate a way to select the locations for the training fingerprints which reduces the amount of required points while improving the accuracy of the algorithms when locating points at room level resolution. We present a comparison of different artificial intelligence decision algorithms and select those with better results. We do a comparison with other systems in the literature and draw conclusions about the improvements obtained in our proposal. Moreover, some techniques such as filtering nonstable access points for improving accuracy are introduced, studied, and validated.

  4. Accuracy of probing attachment levels using a new computerized cemento-enamel junction probe.

    Science.gov (United States)

    Deepa, R; Prakash, Shobha

    2012-01-01

    The assessment of clinical attachment level (CAL) represents the gold standard for diagnosing and monitoring periodontal disease. The aim of the present study was to evaluate the performance of the newly introduced cemento-enamel junction (CEJ) probe in detecting CAL, using CEJ as a fixed reference point, and to compare the CEJ probe with the Florida stent probe (FSP) as well as with a standard manual probe, University of North Carolina-15 (UNC-15). Three examiners recorded the probing attachment level in 384 sites in case group (chronic periodontitis), and in 176 sites, in control group (healthy periodontal status), using the three probes. Subjects included both the sexes and ranged from 35 to 45 years. The experimental design was structured to balance the intra- and inter-examiner consistency at the same site during the two visits. CEJ probe showed higher intra-and inter-examiner consistency over both FSP and UNC-15 in both the case and control groups. Frequency distribution of differences of various magnitudes of repeated measurements ≤1 mm was in the higher range of 86.8% to 87.5% for CEJ probe. The FSP was more reproducible than UNC-15 in detecting relative attachment level (RAL). CEJ automated probe was found to have greatest potential for accuracy and consistency in detecting CAL than FSP and UNC-15. The automated probes appeared to be more reproducible than manual probes.

  5. Automated Algorithms for Quantum-Level Accuracy in Atomistic Simulations: LDRD Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Aidan Patrick; Schultz, Peter Andrew; Crozier, Paul; Moore, Stan Gerald; Swiler, Laura Painton; Stephens, John Adam; Trott, Christian Robert; Foiles, Stephen Martin; Tucker, Garritt J. (Drexel University)

    2014-09-01

    This report summarizes the result of LDRD project 12-0395, titled "Automated Algorithms for Quantum-level Accuracy in Atomistic Simulations." During the course of this LDRD, we have developed an interatomic potential for solids and liquids called Spectral Neighbor Analysis Poten- tial (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected on to a basis of hyperspherical harmonics in four dimensions. The SNAP coef- ficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. Global optimization methods in the DAKOTA software package are used to seek out good choices of hyperparameters that define the overall structure of the SNAP potential. FitSnap.py, a Python-based software pack- age interfacing to both LAMMPS and DAKOTA is used to formulate the linear regression problem, solve it, and analyze the accuracy of the resultant SNAP potential. We describe a SNAP potential for tantalum that accurately reproduces a variety of solid and liquid properties. Most significantly, in contrast to existing tantalum potentials, SNAP correctly predicts the Peierls barrier for screw dislocation motion. We also present results from SNAP potentials generated for indium phosphide (InP) and silica (SiO 2 ). We describe efficient algorithms for calculating SNAP forces and energies in molecular dynamics simulations using massively parallel computers

  6. Image accuracy and representational enhancement through low-level, multi-sensor integration techniques

    International Nuclear Information System (INIS)

    Baker, J.E.

    1993-05-01

    Multi-Sensor Integration (MSI) is the combining of data and information from more than one source in order to generate a more reliable and consistent representation of the environment. The need for MSI derives largely from basic ambiguities inherent in our current sensor imaging technologies. These ambiguities exist as long as the mapping from reality to image is not 1-to-1. That is, if different 44 realities'' lead to identical images, a single image cannot reveal the particular reality which was the truth. MSI techniques can be divided into three categories based on the relative information content of the original images with that of the desired representation: (1) ''detail enhancement,'' wherein the relative information content of the original images is less rich than the desired representation; (2) ''data enhancement,'' wherein the MSI techniques axe concerned with improving the accuracy of the data rather than either increasing or decreasing the level of detail; and (3) ''conceptual enhancement,'' wherein the image contains more detail than is desired, making it difficult to easily recognize objects of interest. In conceptual enhancement one must group pixels corresponding to the same conceptual object and thereby reduce the level of extraneous detail. This research focuses on data and conceptual enhancement algorithms. To be useful in many real-world applications, e.g., autonomous or teleoperated robotics, real-time feedback is critical. But, many MSI/image processing algorithms require significant processing time. This is especially true of feature extraction, object isolation, and object recognition algorithms due to their typical reliance on global or large neighborhood information. This research attempts to exploit the speed currently available in state-of-the-art digitizers and highly parallel processing systems by developing MSI algorithms based on pixel rather than global-level features

  7. Experimental Investigation of Liquid-Level Measuring Accuracy in a Low Pressure Environment

    International Nuclear Information System (INIS)

    Adamson, D.J.

    1996-10-01

    Dip Tubes which are used for determining liquid level in many processes at SRS will be used to measure the liquid level of the Am/Cm solution in the Feed Tank at the MPPF. The Feed Tank operates under a vacuum, therefore the Dip Tubes will operate under a vacuum. Uncertainty in how accurate the Dip Tubes would perform in a vacuum environment led to testing. The Am/Cm Melter Liquid-Feed Tank measurement test was mocked-up per Figure 1. The Feed Tank was designed to simulate actual conditions in which the Dip Tubes would measure the differential pressure. The Feed Tank was made of Stainless Steel with a Lexan window to view inside the tank during testing. The Feed Tank was built per Drawing SRT-ETF-DD-96008, Revision A. The accuracy of the Dip Tubes was checked first by filling the Feed Tank at a flow rate of 3.5 L/min and venting it to the atmosphere. Figure 2 shows that the Dip Tubes were responsive and accurate when compared to the data from the measuring scale on the view window. Then tests were conducted with 23y Hg vacuum inside the tank and water flow rates of 3.9 L/min, 1.8 L/min, and 0.7 L/min being fed to the tank. The data from each test are depicted in Figure 3, Figure 4, and Figure 5, respectively. The Dip Tubes responded accurately for the three test with a maximum error range of +0.31y to -0.19y when compared to the measuring scale located next to the view window on the Feed Tank

  8. Convolutional Neural Network Achieves Human-level Accuracy in Music Genre Classification

    OpenAIRE

    Dong, Mingwen

    2018-01-01

    Music genre classification is one example of content-based analysis of music signals. Traditionally, human-engineered features were used to automatize this task and 61% accuracy has been achieved in the 10-genre classification. However, it's still below the 70% accuracy that humans could achieve in the same task. Here, we propose a new method that combines knowledge of human perception study in music genre classification and the neurophysiology of the auditory system. The method works by trai...

  9. Millimetre Level Accuracy GNSS Positioning with the Blind Adaptive Beamforming Method in Interference Environments

    Directory of Open Access Journals (Sweden)

    Saeed Daneshmand

    2016-10-01

    Full Text Available The use of antenna arrays in Global Navigation Satellite System (GNSS applications is gaining significant attention due to its superior capability to suppress both narrowband and wideband interference. However, the phase distortions resulting from array processing may limit the applicability of these methods for high precision applications using carrier phase based positioning techniques. This paper studies the phase distortions occurring with the adaptive blind beamforming method in which satellite angle of arrival (AoA information is not employed in the optimization problem. To cater to non-stationary interference scenarios, the array weights of the adaptive beamformer are continuously updated. The effects of these continuous updates on the tracking parameters of a GNSS receiver are analyzed. The second part of this paper focuses on reducing the phase distortions during the blind beamforming process in order to allow the receiver to perform carrier phase based positioning by applying a constraint on the structure of the array configuration and by compensating the array uncertainties. Limitations of the previous methods are studied and a new method is proposed that keeps the simplicity of the blind beamformer structure and, at the same time, reduces tracking degradations while achieving millimetre level positioning accuracy in interference environments. To verify the applicability of the proposed method and analyze the degradations, array signals corresponding to the GPS L1 band are generated using a combination of hardware and software simulators. Furthermore, the amount of degradation and performance of the proposed method under different conditions are evaluated based on Monte Carlo simulations.

  10. Improving The Accuracy Of Bluetooth Based Travel Time Estimation Using Low-Level Sensor Data

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Tørholm Christensen, Lars; Krishnan, Rajesh

    2013-01-01

    triggered by a single device. This could lead to location ambiguity and reduced accuracy of travel time estimation. Therefore, the accuracy of travel time estimations by Bluetooth Technology (BT) depends upon how location ambiguity is handled by the estimation method. The issue of multiple detection events...... in the context of travel time estimation by BT has been considered by various researchers. However, treatment of this issue has remained simplistic so far. Most previous studies simply used the first detection event (Enter-Enter) as the best estimate. No systematic analysis for exploring the most accurate method...... of estimating travel time using multiple detection events has been conducted. In this study different aspects of BT detection zone, including size and its impact on the accuracy of travel time estimation, are discussed. Moreover, four alternative methods are applied; namely, Enter-Enter, Leave-Leave, Peak...

  11. High construal level can help negotiators to reach integrative agreements: The role of information exchange and judgement accuracy.

    Science.gov (United States)

    Wening, Stefanie; Keith, Nina; Abele, Andrea E

    2016-06-01

    In negotiations, a focus on interests (why negotiators want something) is key to integrative agreements. Yet, many negotiators spontaneously focus on positions (what they want), with suboptimal outcomes. Our research applies construal-level theory to negotiations and proposes that a high construal level instigates a focus on interests during negotiations which, in turn, positively affects outcomes. In particular, we tested the notion that the effect of construal level on outcomes was mediated by information exchange and judgement accuracy. Finally, we expected the mere mode of presentation of task material to affect construal levels and manipulated construal levels using concrete versus abstract negotiation tasks. In two experiments, participants negotiated in dyads in either a high- or low-construal-level condition. In Study 1, high-construal-level dyads outperformed dyads in the low-construal-level condition; this main effect was mediated by information exchange. Study 2 replicated both the main and mediation effects using judgement accuracy as mediator and additionally yielded a positive effect of a high construal level on a second, more complex negotiation task. These results not only provide empirical evidence for the theoretically proposed link between construal levels and negotiation outcomes but also shed light on the processes underlying this effect. © 2015 The British Psychological Society.

  12. Probe-level linear model fitting and mixture modeling results in high accuracy detection of differential gene expression

    Directory of Open Access Journals (Sweden)

    Lemieux Sébastien

    2006-08-01

    Full Text Available Abstract Background The identification of differentially expressed genes (DEGs from Affymetrix GeneChips arrays is currently done by first computing expression levels from the low-level probe intensities, then deriving significance by comparing these expression levels between conditions. The proposed PL-LM (Probe-Level Linear Model method implements a linear model applied on the probe-level data to directly estimate the treatment effect. A finite mixture of Gaussian components is then used to identify DEGs using the coefficients estimated by the linear model. This approach can readily be applied to experimental design with or without replication. Results On a wholly defined dataset, the PL-LM method was able to identify 75% of the differentially expressed genes within 10% of false positives. This accuracy was achieved both using the three replicates per conditions available in the dataset and using only one replicate per condition. Conclusion The method achieves, on this dataset, a higher accuracy than the best set of tools identified by the authors of the dataset, and does so using only one replicate per condition.

  13. Improved classification accuracy of powdery mildew infection levels of wine grapes by spatial-spectral analysis of hyperspectral images.

    Science.gov (United States)

    Knauer, Uwe; Matros, Andrea; Petrovic, Tijana; Zanker, Timothy; Scott, Eileen S; Seiffert, Udo

    2017-01-01

    Hyperspectral imaging is an emerging means of assessing plant vitality, stress parameters, nutrition status, and diseases. Extraction of target values from the high-dimensional datasets either relies on pixel-wise processing of the full spectral information, appropriate selection of individual bands, or calculation of spectral indices. Limitations of such approaches are reduced classification accuracy, reduced robustness due to spatial variation of the spectral information across the surface of the objects measured as well as a loss of information intrinsic to band selection and use of spectral indices. In this paper we present an improved spatial-spectral segmentation approach for the analysis of hyperspectral imaging data and its application for the prediction of powdery mildew infection levels (disease severity) of intact Chardonnay grape bunches shortly before veraison. Instead of calculating texture features (spatial features) for the huge number of spectral bands independently, dimensionality reduction by means of Linear Discriminant Analysis (LDA) was applied first to derive a few descriptive image bands. Subsequent classification was based on modified Random Forest classifiers and selective extraction of texture parameters from the integral image representation of the image bands generated. Dimensionality reduction, integral images, and the selective feature extraction led to improved classification accuracies of up to [Formula: see text] for detached berries used as a reference sample (training dataset). Our approach was validated by predicting infection levels for a sample of 30 intact bunches. Classification accuracy improved with the number of decision trees of the Random Forest classifier. These results corresponded with qPCR results. An accuracy of 0.87 was achieved in classification of healthy, infected, and severely diseased bunches. However, discrimination between visually healthy and infected bunches proved to be challenging for a few samples

  14. Geometric Accuracy Investigations of SEVIRI High Resolution Visible (HRV Level 1.5 Imagery

    Directory of Open Access Journals (Sweden)

    Sultan Kocaman Aksakal

    2013-05-01

    Full Text Available GCOS (Global Climate Observing System is a long-term program for monitoring the climate, detecting the changes, and assessing their impacts. Remote sensing techniques are being increasingly used for climate-related measurements. Imagery of the SEVIRI instrument on board of the European geostationary satellites Meteosat-8 and Meteosat-9 are often used for the estimation of essential climate variables. In a joint project between the Swiss GCOS Office and ETH Zurich, geometric accuracy and temporal stability of 1-km resolution HRV channel imagery of SEVIRI have been evaluated over Switzerland. A set of tools and algorithms has been developed for the investigations. Statistical analysis and blunder detection have been integrated in the process for robust evaluation. The relative accuracy is evaluated by tracking large numbers of feature points in consecutive HRV images taken at 15-minute intervals. For the absolute accuracy evaluation, lakes in Switzerland and surroundings are used as reference. 20 lakes digitized from Landsat orthophotos are transformed into HRV images and matched via 2D translation terms at sub-pixel level. The algorithms are tested using HRV images taken on 24 days in 2008 (2 days per month. The results show that 2D shifts that are up to 8 pixels are present both in relative and absolute terms.

  15. On the Accuracy of Iranian EFL Students' Reading Self-assessment and their Level of Reading Proficiency

    Directory of Open Access Journals (Sweden)

    Moein Shokr

    2015-10-01

    Full Text Available Reviewing the literature on self-assessment as an alternative method of assessment we find advocates claiming for the accuracy of the students’ self-assessments in general with little focus on their level of proficiency. With an eye on the students’ level of reading proficiency, the present study aimed at investigating the relationship between students’ reading self-assessment (as a formative and alternative method of assessment on the one hand, and teacher assessment (as a formative type of assessment as well as students’ final examination scores (as a summative and traditional method of assessment on the other. To this end, 65 students of Islamic Azad University- Tehran South Branch were selected to participate in this study. Initially, participants received PET test as pretest for assigning them into different levels of reading proficiency. Based upon the results of the pretest, participants were assigned to elementary and intermediate levels. Throughout the whole semester self-assessment questionnaire was employed for five times. Descriptive statistics and Pearson correlation were the data analysis techniques performed. The results of the study revealed a significant relationship between the intermediate learners’ self-ratings and teacher assessments; however, the results indicated no significant relationship between elementary learners’ self-assessments and teacher assessments. Also, the correlations between students’ self-assessments and their final examination scores were not significant for both levels. Therefore, given the teacher assessment as the yardstick, the accuracy of the intermediate levels and the inaccuracy of the elementary learners’ self-assessments could be concluded. Finally, the low correlation between the learners’ self-assessments and their scores on traditional final examination led the researcher to attribute it to the different nature of these two assessment types.

  16. Estimation of background noise level on seismic station using statistical analysis for improved analysis accuracy

    Science.gov (United States)

    Han, S. M.; Hahm, I.

    2015-12-01

    We evaluated the background noise level of seismic stations in order to collect the observation data of high quality and produce accurate seismic information. Determining of the background noise level was used PSD (Power Spectral Density) method by McNamara and Buland (2004) in this study. This method that used long-term data is influenced by not only innate electronic noise of sensor and a pulse wave resulting from stabilizing but also missing data and controlled by the specified frequency which is affected by the irregular signals without site characteristics. It is hard and inefficient to implement process that filters out the abnormal signal within the automated system. To solve these problems, we devised a method for extracting the data which normally distributed with 90 to 99% confidence intervals at each period. The availability of the method was verified using 62-seismic stations with broadband and short-period sensors operated by the KMA (Korea Meteorological Administration). Evaluation standards were NHNM (New High Noise Model) and NLNM (New Low Noise Model) published by the USGS (United States Geological Survey). It was designed based on the western United States. However, Korean Peninsula surrounded by the ocean on three sides has a complicated geological structure and a high population density. So, we re-designed an appropriate model in Korean peninsula by statistically combined result. The important feature is that secondary-microseism peak appeared at a higher frequency band. Acknowledgements: This research was carried out as a part of "Research for the Meteorological and Earthquake Observation Technology and Its Application" supported by the 2015 National Institute of Meteorological Research (NIMR) in the Korea Meteorological Administration.

  17. Infrared analyzers for breast milk analysis: fat levels can influence the accuracy of protein measurements.

    Science.gov (United States)

    Kwan, Celia; Fusch, Gerhard; Bahonjic, Aldin; Rochow, Niels; Fusch, Christoph

    2017-10-26

    Currently, there is a growing interest in lacto-engineering in the neonatal intensive care unit, using infrared milk analyzers to rapidly measure the macronutrient content in breast milk before processing and feeding it to preterm infants. However, there is an overlap in the spectral information of different macronutrients, so they can potentially impact the robustness of the measurement. In this study, we investigate whether the measurement of protein is dependent on the levels of fat present while using an infrared milk analyzer. Breast milk samples (n=25) were measured for fat and protein content before and after being completely defatted by centrifugation, using chemical reference methods and near-infrared milk analyzer (Unity SpectraStar) with two different calibration algorithms provided by the manufacturer (released 2009 and 2015). While the protein content remained unchanged, as measured by elemental analysis, measurements by infrared milk analyzer show a difference in protein measurements dependent on fat content; high fat content can lead to falsely high protein content. This difference is less pronounced when measured using the more recent calibration algorithm. Milk analyzer users must be cautious of their devices' measurements, especially if they are changing the matrix of breast milk using more advanced lacto-engineering.

  18. Measurement of shunt amount using radionuclide angiocardiography: accuracy according to level of shunt and associated lesion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Min [Sejong General Hospital, Bucheon (Korea, Republic of)

    2006-08-15

    Determination of pulmonary to systemic blood flow ratio (QP/QS) is important for the management of patients with left-to-right shunt. This study was performed to assess the agreement of Qp/Qs ratio using the radionuclide method and oxymetry, to investigate the factors influencing the agreement, and to know how interchangeable the results of each technique. We compared the Qp/Qs measured by single-pass radionuclide angiocardiography and oxymetry during catheterization in 207 patients who underwent both studies. In radionuclide method, Qp/Qs was calculated from the pulmonary time-activity curves using a gamma variate fit. The correlation and Bland-Altman analysis were performed according to the levels of shunt and associated lesions. The mean Qp/Qs was 1.83 {+-} 0.50 by radionuclide, and 1.74 {+-} 0.51 by oxymetry. The overall correlation coefficient was 0.86 ({rho} 0.001), and Bland-Altman range of agreement encompassing 4SD was 1.05. For atrial septal defect, ventricular septal defect, patent ductus arteriosus, tricuspid and mitral insufficiency, the correlation coefficient was 0.78, 0.90, 0.84, 0.63 and 0.44 and Bland-Altman range was 1.52, 0.74, 0.96, 1.57 and 1.50, respectively. There is good agreement but wide variance between the Qp/Qs ratios by radionuclide method and oxymetry. Associated atrioventricular valvar insufficiency decreases the correlation coefficient and widens the variance. Wide overall variance suggests that Qp/Qs measurements by two techniques should not be used interchangeably.

  19. Measurement of shunt amount using radionuclide angiocardiography: accuracy according to level of shunt and associated lesion

    International Nuclear Information System (INIS)

    Kim, Yang Min

    2006-01-01

    Determination of pulmonary to systemic blood flow ratio (QP/QS) is important for the management of patients with left-to-right shunt. This study was performed to assess the agreement of Qp/Qs ratio using the radionuclide method and oxymetry, to investigate the factors influencing the agreement, and to know how interchangeable the results of each technique. We compared the Qp/Qs measured by single-pass radionuclide angiocardiography and oxymetry during catheterization in 207 patients who underwent both studies. In radionuclide method, Qp/Qs was calculated from the pulmonary time-activity curves using a gamma variate fit. The correlation and Bland-Altman analysis were performed according to the levels of shunt and associated lesions. The mean Qp/Qs was 1.83 ± 0.50 by radionuclide, and 1.74 ± 0.51 by oxymetry. The overall correlation coefficient was 0.86 (ρ 0.001), and Bland-Altman range of agreement encompassing 4SD was 1.05. For atrial septal defect, ventricular septal defect, patent ductus arteriosus, tricuspid and mitral insufficiency, the correlation coefficient was 0.78, 0.90, 0.84, 0.63 and 0.44 and Bland-Altman range was 1.52, 0.74, 0.96, 1.57 and 1.50, respectively. There is good agreement but wide variance between the Qp/Qs ratios by radionuclide method and oxymetry. Associated atrioventricular valvar insufficiency decreases the correlation coefficient and widens the variance. Wide overall variance suggests that Qp/Qs measurements by two techniques should not be used interchangeably

  20. Improved initial guess with semi-subpixel level accuracy in digital image correlation by feature-based method

    Science.gov (United States)

    Zhang, Yunlu; Yan, Lei; Liou, Frank

    2018-05-01

    The quality initial guess of deformation parameters in digital image correlation (DIC) has a serious impact on convergence, robustness, and efficiency of the following subpixel level searching stage. In this work, an improved feature-based initial guess (FB-IG) scheme is presented to provide initial guess for points of interest (POIs) inside a large region. Oriented FAST and Rotated BRIEF (ORB) features are semi-uniformly extracted from the region of interest (ROI) and matched to provide initial deformation information. False matched pairs are eliminated by the novel feature guided Gaussian mixture model (FG-GMM) point set registration algorithm, and nonuniform deformation parameters of the versatile reproducing kernel Hilbert space (RKHS) function are calculated simultaneously. Validations on simulated images and real-world mini tensile test verify that this scheme can robustly and accurately compute initial guesses with semi-subpixel level accuracy in cases with small or large translation, deformation, or rotation.

  1. Force and Directional Force Modulation Effects on Accuracy and Variability in Low-Level Pinch Force Tracking.

    Science.gov (United States)

    Park, Sangsoo; Spirduso, Waneen; Eakin, Tim; Abraham, Lawrence

    2018-01-01

    The authors investigated how varying the required low-level forces and the direction of force change affect accuracy and variability of force production in a cyclic isometric pinch force tracking task. Eighteen healthy right-handed adult volunteers performed the tracking task over 3 different force ranges. Root mean square error and coefficient of variation were higher at lower force levels and during minimum reversals compared with maximum reversals. Overall, the thumb showed greater root mean square error and coefficient of variation scores than did the index finger during maximum reversals, but not during minimum reversals. The observed impaired performance during minimum reversals might originate from history-dependent mechanisms of force production and highly coupled 2-digit performance.

  2. Addenbrooke's cognitive examination-revised: normative and accuracy data for seniors with heterogeneous educational level in Brazil.

    Science.gov (United States)

    César, Karolina G; Yassuda, Mônica S; Porto, Fabio H G; Brucki, Sonia M D; Nitrini, Ricardo

    2017-08-01

    Several cognitive tools have been developed aiming to diagnose dementia. The cognitive battery Addenbrooke's Cognitive Examination - Revised (ACE-R) has been used to detect cognitive impairment; however, there are few studies including samples with low education. The aim of the study was to provide ACE-R norms for seniors within a lower education, including illiterates. An additional aim was to examine the accuracy of the ACE-R to detect dementia and cognitive impairment no dementia (CIND). Data originated from an epidemiological study conducted in the municipality of Tremembé, Brazil. The Brazilian version of ACE-R was applied as part of the cognitive assessment in all participants. Of the 630 participants, 385 were classified as cognitively normal (CN) and were included in the normative data set, 110 individuals were diagnosed with dementia, and 135 were classified as having CIND. ACE-R norms were provided with the sample stratified into age and education bands. ACE-R total scores varied significantly according to age, education, and sex. To distinguish CN from dementia, a cut-off of 64 points was established (sensitivity 91%, specificity 76%) and to differentiate CN from CIND the best cut-off was 69 points (sensitivity 73%, specificity 65%). Cut-off scores varied according to the educational level. This study offers normative and accuracy parameters for seniors with lower education and it should expand the use of the ACE-R for this population segment.

  3. The effect of base image window level selection on the dimensional measurement accuracy of resultant three-dimensional image displays

    International Nuclear Information System (INIS)

    Kurmis, A.P.; Hearn, T.C.; Reynolds, K.J.

    2003-01-01

    Purpose: The aim of this study was to determine the effect of base image window level selection on direct linear measurement of knee structures displayed using new magnetic resonance (MR)-based three-dimensional reconstructed computer imaging techniques. Methods: A prospective comparative study was performed using a series of three-dimensional knee images, generated from conventional MR imaging (MRI) sections. Thirty distinct anatomical structural features were identified within the image series of which repeated measurements were compared at 10 different window grey scale levels. Results: Statistical analysis demonstrated an excellent raw correlation between measurements and suggested no significant difference between measurements made at each of the 10 window level settings (P>0.05). Conclusions: The findings of this study suggest that unlike conventional MR or CT applications, grey scale window level selection at the time of imaging does not significantly affect the visual quality of resultant three-dimensional reconstructed images and hence the accuracy of subsequent direct linear measurement. The diagnostic potential of clinical progression from routine two-dimensional to advanced three-dimensional reconstructed imaging techniques may therefore be less likely to be degraded by inappropriate MR technician image windowing during the capturing of image series

  4. High accuracy results for the energy levels of the molecular ions H+2, D+2 and HD+, up to J = 2

    International Nuclear Information System (INIS)

    Karr, J Ph; Hilico, L

    2006-01-01

    We present a nonrelativistic calculation of the rotation-vibration levels of the molecular ions H + 2 , D + 2 and HD + , relying on the diagonalization of the exact three-body Hamiltonian in a variational basis. The J = 2 levels are obtained with a very high accuracy of 10 -14 au (for most levels) representing an improvement by five orders of magnitude over previous calculations. The accuracy is also improved for the J = 1 levels of H + 2 and D + 2 with respect to earlier works. Moreover, we have computed the sensitivities of the energy levels with respect to the mass ratios, allowing these levels to be used for metrological purposes

  5. Accuracy of MRI diagnosis of internal derangement of the knee in a non-specialized tertiary level referral teaching hospital

    International Nuclear Information System (INIS)

    Challen, J.; Tang, Y. M.; Stuckey, S.; Hazratwala, K.

    2007-01-01

    Full text: This study was designed to assess the accuracy of knee MRl examinations carried out in a general tertiary referral hospital without a musculoskeletal fellowship trained radiologist. The study included all patients who had undergone a knee arthroscopy carried out within a 2-year period and who had had a prior MRl knee examination, where both were carried out at this institution. The accuracy of the MRl knee examination was determined by correlation to the arthroscopy report. The accuracy for diagnosis of meniscal and cartilage injuries, in this setting, was found to be similar to a published meta-analysis of previous studies correlating knee MRl and arthroscopy. The overall accuracy of this study was better than the previous similar study. However, the accuracy for diagnosing ACL injuries was lower than in the meta-analysis. The potential reasons for this and other sources of error are discussed

  6. Automatic optimal filament segmentation with sub-pixel accuracy using generalized linear models and B-spline level-sets.

    Science.gov (United States)

    Xiao, Xun; Geyer, Veikko F; Bowne-Anderson, Hugo; Howard, Jonathon; Sbalzarini, Ivo F

    2016-08-01

    Biological filaments, such as actin filaments, microtubules, and cilia, are often imaged using different light-microscopy techniques. Reconstructing the filament curve from the acquired images constitutes the filament segmentation problem. Since filaments have lower dimensionality than the image itself, there is an inherent trade-off between tracing the filament with sub-pixel accuracy and avoiding noise artifacts. Here, we present a globally optimal filament segmentation method based on B-spline vector level-sets and a generalized linear model for the pixel intensity statistics. We show that the resulting optimization problem is convex and can hence be solved with global optimality. We introduce a simple and efficient algorithm to compute such optimal filament segmentations, and provide an open-source implementation as an ImageJ/Fiji plugin. We further derive an information-theoretic lower bound on the filament segmentation error, quantifying how well an algorithm could possibly do given the information in the image. We show that our algorithm asymptotically reaches this bound in the spline coefficients. We validate our method in comprehensive benchmarks, compare with other methods, and show applications from fluorescence, phase-contrast, and dark-field microscopy. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Relation between riding quality of MAGLEV vehicle and guideway construction accuracy. Chodendo jiki fujoshiki tetsudo guideway no seko seido to norigokochi level

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, A; Hashimoto, S; Furukawa, A [Railway Technology Research Institute, Tokyo (Japan)

    1994-01-15

    Good riding quality of MAGLEV vehicle requires construction of its guideway to a high level of accuracy. This paper discusses the relation of the power spectrum density (hereinafter the PSD) made up of guideway construction accuracy and its deviation with the level of riding comfort. The discussion uses the 'riding comfort affecting coefficient' consisting of the unit construction length, vehicle's travelling speed, and vibration characteristics. The PSD, which has been used to evaluate track deviation in the iron wheel/rail system railways, is derived from the number of limit exceeded point, the value 'P' as a track deviation coefficient, and the PSD. The relation between the standard deviation in construction errors and the PSD was derived based on track construction methods. This calculation method is characterized by a function with a step form. The relation between the deviation and the level was quantified using this PSD. Its practicability was verified by a simulated re-inspection of the guideway deviation. Correlation between the level and the construction accuracy was elucidated, and a method for determining the criteria for construction accuracy was established. A side wall beam installing vehicle has been fabricated on a trial basis for a side wall system for the guideway, and installation accuracy tests are being carried out. 14 refs., 12 figs., 3 tabs.

  8. Use of Low-Level Sensor Data to Improve the Accuracy of Bluetooth-Based Travel Time Estimation

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Christensen, Lars Tørholm; Krishnan, Rajesh

    2013-01-01

    by a single device. The latter situation could lead to location ambiguity and could reduce the accuracy of travel time estimation. Therefore, the accuracy of travel time estimation by Bluetooth technology depends on how location ambiguity is handled by the estimation method. The issue of multiple detection...... events in the context of travel time estimation by Bluetooth technology has been considered by various researchers. However, treatment of this issue has been simplistic. Most previous studies have used the first detection event (enter-enter) as the best estimate. No systematic analysis has been conducted...... to explore the most accurate method of travel time estimation with multiple detection events. In this study, different aspects of the Bluetooth detection zone, including size and impact on the accuracy of travel time estimation, were discussed. Four methods were applied to estimate travel time: enter...

  9. Plasma Lactate Dehydrogenase Levels Predict Mortality in Acute Aortic Syndromes: A Diagnostic Accuracy and Observational Outcome Study.

    Science.gov (United States)

    Morello, Fulvio; Ravetti, Anna; Nazerian, Peiman; Liedl, Giovanni; Veglio, Maria Grazia; Battista, Stefania; Vanni, Simone; Pivetta, Emanuele; Montrucchio, Giuseppe; Mengozzi, Giulio; Rinaldi, Mauro; Moiraghi, Corrado; Lupia, Enrico

    2016-02-01

    In acute aortic syndromes (AAS), organ malperfusion represents a key event impacting both on diagnosis and outcome. Increased levels of plasma lactate dehydrogenase (LDH), a biomarker of malperfusion, have been reported in AAS, but the performance of LDH for the diagnosis of AAS and the relation of LDH with outcome in AAS have not been evaluated so far.This was a bi-centric prospective diagnostic accuracy study and a cohort outcome study. From 2008 to 2014, patients from 2 Emergency Departments suspected of having AAS underwent LDH assay at presentation. A final diagnosis was obtained by aortic imaging. Patients diagnosed with AAS were followed-up for in-hospital mortality.One thousand five hundred seventy-eight consecutive patients were clinically eligible, and 999 patients were included in the study. The final diagnosis was AAS in 201 (20.1%) patients. Median LDH was 424 U/L (interquartile range [IQR] 367-557) in patients with AAS and 383 U/L (IQR 331-460) in patients with alternative diagnoses (P < 0.001). Using a cutoff of 450 U/L, the sensitivity of LDH for AAS was 44% (95% confidence interval [CI] 37-51) and the specificity was 73% (95% CI 69-76). Overall in-hospital mortality for AAS was 23.8%. Mortality was 32.6% in patients with LDH ≥ 450 U/L and 16.8% in patients with LDH < 450 U/L (P = 0.006). Following stratification according to LDH quartiles, in-hospital mortality was 12% in the first (lowest) quartile, 18.4% in the second quartile, 23.5% in the third quartile, and 38% in the fourth (highest) quartile (P = 0.01). LDH ≥ 450 U/L was further identified as an independent predictor of death in AAS both in univariate and in stepwise logistic regression analyses (odds ratio 2.28, 95% CI 1.11-4.66; P = 0.025), in addition to well-established risk markers such as advanced age and hypotension. Subgroup analysis showed excess mortality in association with LDH ≥ 450 U/L in elderly, hemodynamically stable and in nonsurgically

  10. Precision and accuracy of manual water-level measurements taken in the Yucca Mountain area, Nye County, Nevada, 1988--1990

    International Nuclear Information System (INIS)

    Boucher, M.S.

    1994-01-01

    Water-level measurements have been made in deep boreholes in the Yucca Mountain area, Nye County, Nevada, since 1983 in support of the US Department of Energy's Yucca Mountain Project, which is an evaluation of the area to determine its suit-ability as a potential storage area for high-level nuclear waste. Water-level measurements were taken either manually, using various water-level measuring equipment such as steel tapes, or they were taken continuously, using automated data recorders and pressure transducers. This report presents precision range and accuracy data established for manual water-level measurements taken in the Yucca Mountain area, 1988--90

  11. Braille Reading Accuracy of Students Who Are Visually Impaired: The Effects of Gender, Age at Vision Loss, and Level of Education

    Science.gov (United States)

    Argyropoulos, Vassilis; Papadimitriou, Vassilios

    2015-01-01

    Introduction: The present study assesses the performance of students who are visually impaired (that is, those who are blind or have low vision) in braille reading accuracy and examines potential correlations among the error categories on the basis of gender, age at loss of vision, and level of education. Methods: Twenty-one visually impaired…

  12. Role of Effective Density in improving the accuracy of bottom pressure based sea level measurements - A case study from Gulf of Guinea

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Mehra, P.; Desai, R.G.P.; Dotse, J.; Odametey, J.T.; Nkebi, E.K.; Vijaykumar, K.; Prabhudesai, S.P.

    of the sea water, as a result of turbulence induced by wind forcing and impact of rain drops, is suspected to be responsible for the observed effective reduction in the in situ density of this shallow water body The accuracy of bottom-pressure based sea level...

  13. Effect of radiation dose level on accuracy and precision of manual size measurements in chest tomosynthesis evaluated using simulated pulmonary nodules

    International Nuclear Information System (INIS)

    Soederman, Christina; Allansdotter Johnsson, Aase; Vikgren, Jenny; Rossi Norrlund, Rauni; Molnar, David; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus

    2016-01-01

    The aim of the present study was to investigate the dependency of the accuracy and precision of nodule diameter measurements on the radiation dose level in chest tomosynthesis. Artificial ellipsoid-shaped nodules with known dimensions were inserted in clinical chest tomosynthesis images. Noise was added to the images in order to simulate radiation dose levels corresponding to effective doses for a standard-sized patient of 0.06 and 0.04 mSv. These levels were compared with the original dose level, corresponding to an effective dose of 0.12 mSv for a standard-sized patient. Four thoracic radiologists measured the longest diameter of the nodules. The study was restricted to nodules located in high-dose areas of the tomosynthesis projection radiographs. A significant decrease of the measurement accuracy and intra-observer variability was seen for the lowest dose level for a subset of the observers. No significant effect of dose level on the interobserver variability was found. The number of non-measurable small nodules (≤5 mm) was higher for the two lowest dose levels compared with the original dose level. In conclusion, for pulmonary nodules at positions in the lung corresponding to locations in high-dose areas of the projection radiographs, using a radiation dose level resulting in an effective dose of 0.06 mSv to a standard-sized patient may be possible in chest tomosynthesis without affecting the accuracy and precision of nodule diameter measurements to any large extent. However, an increasing number of non-measurable small nodules (≤5 mm) with decreasing radiation dose may raise some concerns regarding an applied general dose reduction for chest tomosynthesis examinations in the clinical praxis. (authors)

  14. Effect of conductance linearity and multi-level cell characteristics of TaOx-based synapse device on pattern recognition accuracy of neuromorphic system

    Science.gov (United States)

    Sung, Changhyuck; Lim, Seokjae; Kim, Hyungjun; Kim, Taesu; Moon, Kibong; Song, Jeonghwan; Kim, Jae-Joon; Hwang, Hyunsang

    2018-03-01

    To improve the classification accuracy of an image data set (CIFAR-10) by using analog input voltage, synapse devices with excellent conductance linearity (CL) and multi-level cell (MLC) characteristics are required. We analyze the CL and MLC characteristics of TaOx-based filamentary resistive random access memory (RRAM) to implement the synapse device in neural network hardware. Our findings show that the number of oxygen vacancies in the filament constriction region of the RRAM directly controls the CL and MLC characteristics. By adopting a Ta electrode (instead of Ti) and the hot-forming step, we could form a dense conductive filament. As a result, a wide range of conductance levels with CL is achieved and significantly improved image classification accuracy is confirmed.

  15. Empathic Accuracy in Male Adolescents with Conduct Disorder and Higher versus Lower Levels of Callous-Unemotional Traits.

    Science.gov (United States)

    Martin-Key, N; Brown, T; Fairchild, G

    2017-10-01

    Adolescents with disruptive behavior disorders are reported to show deficits in empathy and emotion recognition. However, prior studies have mainly used questionnaires to measure empathy or experimental paradigms that are lacking in ecological validity. We used an empathic accuracy (EA) task to study EA, emotion recognition, and affective empathy in 77 male adolescents aged 13-18 years: 37 with Conduct Disorder (CD) and 40 typically-developing controls. The CD sample was divided into higher callous-emotional traits (CD/CU+) and lower callous-unemotional traits (CD/CU-) subgroups using a median split. Participants watched films of actors recalling happy, sad, surprised, angry, disgusted or fearful autobiographical experiences and provided continuous ratings of emotional intensity (assessing EA), as well as naming the emotion (recognition) and reporting the emotion they experienced themselves (affective empathy). The CD and typically-developing groups did not significantly differ in EA and there were also no differences between the CD/CU+ and CD/CU- subgroups. Participants with CD were significantly less accurate than controls in recognizing sadness, fear, and disgust, all ps sadness, fear, and disgust relative to controls, all ps < 0.010, rs ≥ 0.33, whereas the CD/CU+ and CD/CU- subgroups did not differ in affective empathy. These results extend prior research by demonstrating affective empathy and emotion recognition deficits in adolescents with CD using a more ecologically-valid task, and challenge the view that affective empathy deficits are specific to CD/CU+.

  16. The Development of Expertise in Radiology: In Chest Radiograph Interpretation, "Expert" Search Pattern May Predate "Expert" Levels of Diagnostic Accuracy for Pneumothorax Identification.

    Science.gov (United States)

    Kelly, Brendan S; Rainford, Louise A; Darcy, Sarah P; Kavanagh, Eoin C; Toomey, Rachel J

    2016-07-01

    Purpose To investigate the development of chest radiograph interpretation skill through medical training by measuring both diagnostic accuracy and eye movements during visual search. Materials and Methods An institutional exemption from full ethical review was granted for the study. Five consultant radiologists were deemed the reference expert group, and four radiology registrars, five senior house officers (SHOs), and six interns formed four clinician groups. Participants were shown 30 chest radiographs, 14 of which had a pneumothorax, and were asked to give their level of confidence as to whether a pneumothorax was present. Receiver operating characteristic (ROC) curve analysis was carried out on diagnostic decisions. Eye movements were recorded with a Tobii TX300 (Tobii Technology, Stockholm, Sweden) eye tracker. Four eye-tracking metrics were analyzed. Variables were compared to identify any differences between groups. All data were compared by using the Friedman nonparametric method. Results The average area under the ROC curve for the groups increased with experience (0.947 for consultants, 0.792 for registrars, 0.693 for SHOs, and 0.659 for interns; P = .009). A significant difference in diagnostic accuracy was found between consultants and registrars (P = .046). All four eye-tracking metrics decreased with experience, and there were significant differences between registrars and SHOs. Total reading time decreased with experience; it was significantly lower for registrars compared with SHOs (P = .046) and for SHOs compared with interns (P = .025). Conclusion Chest radiograph interpretation skill increased with experience, both in terms of diagnostic accuracy and visual search. The observed level of experience at which there was a significant difference was higher for diagnostic accuracy than for eye-tracking metrics. (©) RSNA, 2016 Online supplemental material is available for this article.

  17. Smart Device-Supported BDS/GNSS Real-Time Kinematic Positioning for Sub-Meter-Level Accuracy in Urban Location-Based Services

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2016-12-01

    Full Text Available Using mobile smart devices to provide urban location-based services (LBS with sub-meter-level accuracy (around 0.5 m is a major application field for future global navigation satellite system (GNSS development. Real-time kinematic (RTK positioning, which is a widely used GNSS-based positioning approach, can improve the accuracy from about 10–20 m (achieved by the standard positioning services to about 3–5 cm based on the geodetic receivers. In using the smart devices to achieve positioning with sub-meter-level accuracy, a feasible solution of combining the low-cost GNSS module and the smart device is proposed in this work and a user-side GNSS RTK positioning software was developed from scratch based on the Android platform. Its real-time positioning performance was validated by BeiDou Navigation Satellite System/Global Positioning System (BDS/GPS combined RTK positioning under the conditions of a static and kinematic (the velocity of the rover was 50–80 km/h mode in a real urban environment with a SAMSUNG Galaxy A7 smartphone. The results show that the fixed-rates of ambiguity resolution (the proportion of epochs of ambiguities fixed for BDS/GPS combined RTK in the static and kinematic tests were about 97% and 90%, respectively, and the average positioning accuracies (RMS were better than 0.15 m (horizontal and 0.25 m (vertical for the static test, and 0.30 m (horizontal and 0.45 m (vertical for the kinematic test.

  18. Smart Device-Supported BDS/GNSS Real-Time Kinematic Positioning for Sub-Meter-Level Accuracy in Urban Location-Based Services.

    Science.gov (United States)

    Wang, Liang; Li, Zishen; Zhao, Jiaojiao; Zhou, Kai; Wang, Zhiyu; Yuan, Hong

    2016-12-21

    Using mobile smart devices to provide urban location-based services (LBS) with sub-meter-level accuracy (around 0.5 m) is a major application field for future global navigation satellite system (GNSS) development. Real-time kinematic (RTK) positioning, which is a widely used GNSS-based positioning approach, can improve the accuracy from about 10-20 m (achieved by the standard positioning services) to about 3-5 cm based on the geodetic receivers. In using the smart devices to achieve positioning with sub-meter-level accuracy, a feasible solution of combining the low-cost GNSS module and the smart device is proposed in this work and a user-side GNSS RTK positioning software was developed from scratch based on the Android platform. Its real-time positioning performance was validated by BeiDou Navigation Satellite System/Global Positioning System (BDS/GPS) combined RTK positioning under the conditions of a static and kinematic (the velocity of the rover was 50-80 km/h) mode in a real urban environment with a SAMSUNG Galaxy A7 smartphone. The results show that the fixed-rates of ambiguity resolution (the proportion of epochs of ambiguities fixed) for BDS/GPS combined RTK in the static and kinematic tests were about 97% and 90%, respectively, and the average positioning accuracies (RMS) were better than 0.15 m (horizontal) and 0.25 m (vertical) for the static test, and 0.30 m (horizontal) and 0.45 m (vertical) for the kinematic test.

  19. Supervised Machine Learning Algorithms Can Classify Open-Text Feedback of Doctor Performance With Human-Level Accuracy

    Science.gov (United States)

    2017-01-01

    Background Machine learning techniques may be an effective and efficient way to classify open-text reports on doctor’s activity for the purposes of quality assurance, safety, and continuing professional development. Objective The objective of the study was to evaluate the accuracy of machine learning algorithms trained to classify open-text reports of doctor performance and to assess the potential for classifications to identify significant differences in doctors’ professional performance in the United Kingdom. Methods We used 1636 open-text comments (34,283 words) relating to the performance of 548 doctors collected from a survey of clinicians’ colleagues using the General Medical Council Colleague Questionnaire (GMC-CQ). We coded 77.75% (1272/1636) of the comments into 5 global themes (innovation, interpersonal skills, popularity, professionalism, and respect) using a qualitative framework. We trained 8 machine learning algorithms to classify comments and assessed their performance using several training samples. We evaluated doctor performance using the GMC-CQ and compared scores between doctors with different classifications using t tests. Results Individual algorithm performance was high (range F score=.68 to .83). Interrater agreement between the algorithms and the human coder was highest for codes relating to “popular” (recall=.97), “innovator” (recall=.98), and “respected” (recall=.87) codes and was lower for the “interpersonal” (recall=.80) and “professional” (recall=.82) codes. A 10-fold cross-validation demonstrated similar performance in each analysis. When combined together into an ensemble of multiple algorithms, mean human-computer interrater agreement was .88. Comments that were classified as “respected,” “professional,” and “interpersonal” related to higher doctor scores on the GMC-CQ compared with comments that were not classified (P.05). Conclusions Machine learning algorithms can classify open-text feedback

  20. Supervised Machine Learning Algorithms Can Classify Open-Text Feedback of Doctor Performance With Human-Level Accuracy.

    Science.gov (United States)

    Gibbons, Chris; Richards, Suzanne; Valderas, Jose Maria; Campbell, John

    2017-03-15

    Machine learning techniques may be an effective and efficient way to classify open-text reports on doctor's activity for the purposes of quality assurance, safety, and continuing professional development. The objective of the study was to evaluate the accuracy of machine learning algorithms trained to classify open-text reports of doctor performance and to assess the potential for classifications to identify significant differences in doctors' professional performance in the United Kingdom. We used 1636 open-text comments (34,283 words) relating to the performance of 548 doctors collected from a survey of clinicians' colleagues using the General Medical Council Colleague Questionnaire (GMC-CQ). We coded 77.75% (1272/1636) of the comments into 5 global themes (innovation, interpersonal skills, popularity, professionalism, and respect) using a qualitative framework. We trained 8 machine learning algorithms to classify comments and assessed their performance using several training samples. We evaluated doctor performance using the GMC-CQ and compared scores between doctors with different classifications using t tests. Individual algorithm performance was high (range F score=.68 to .83). Interrater agreement between the algorithms and the human coder was highest for codes relating to "popular" (recall=.97), "innovator" (recall=.98), and "respected" (recall=.87) codes and was lower for the "interpersonal" (recall=.80) and "professional" (recall=.82) codes. A 10-fold cross-validation demonstrated similar performance in each analysis. When combined together into an ensemble of multiple algorithms, mean human-computer interrater agreement was .88. Comments that were classified as "respected," "professional," and "interpersonal" related to higher doctor scores on the GMC-CQ compared with comments that were not classified (P.05). Machine learning algorithms can classify open-text feedback of doctor performance into multiple themes derived by human raters with high

  1. Principal Components of Superhigh-Dimensional Statistical Features and Support Vector Machine for Improving Identification Accuracies of Different Gear Crack Levels under Different Working Conditions

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-01-01

    Full Text Available Gears are widely used in gearbox to transmit power from one shaft to another. Gear crack is one of the most frequent gear fault modes found in industry. Identification of different gear crack levels is beneficial in preventing any unexpected machine breakdown and reducing economic loss because gear crack leads to gear tooth breakage. In this paper, an intelligent fault diagnosis method for identification of different gear crack levels under different working conditions is proposed. First, superhigh-dimensional statistical features are extracted from continuous wavelet transform at different scales. The number of the statistical features extracted by using the proposed method is 920 so that the extracted statistical features are superhigh dimensional. To reduce the dimensionality of the extracted statistical features and generate new significant low-dimensional statistical features, a simple and effective method called principal component analysis is used. To further improve identification accuracies of different gear crack levels under different working conditions, support vector machine is employed. Three experiments are investigated to show the superiority of the proposed method. Comparisons with other existing gear crack level identification methods are conducted. The results show that the proposed method has the highest identification accuracies among all existing methods.

  2. Accuracy Enhancement for Forecasting Water Levels of Reservoirs and River Streams Using a Multiple-Input-Pattern Fuzzification Approach

    Directory of Open Access Journals (Sweden)

    Nariman Valizadeh

    2014-01-01

    Full Text Available Water level forecasting is an essential topic in water management affecting reservoir operations and decision making. Recently, modern methods utilizing artificial intelligence, fuzzy logic, and combinations of these techniques have been used in hydrological applications because of their considerable ability to map an input-output pattern without requiring prior knowledge of the criteria influencing the forecasting procedure. The artificial neurofuzzy interface system (ANFIS is one of the most accurate models used in water resource management. Because the membership functions (MFs possess the characteristics of smoothness and mathematical components, each set of input data is able to yield the best result using a certain type of MF in the ANFIS models. The objective of this study is to define the different ANFIS model by applying different types of MFs for each type of input to forecast the water level in two case studies, the Klang Gates Dam and Rantau Panjang station on the Johor river in Malaysia, to compare the traditional ANFIS model with the new introduced one in two different situations, reservoir and stream, showing the new approach outweigh rather than the traditional one in both case studies. This objective is accomplished by evaluating the model fitness and performance in daily forecasting.

  3. Accuracy enhancement for forecasting water levels of reservoirs and river streams using a multiple-input-pattern fuzzification approach.

    Science.gov (United States)

    Valizadeh, Nariman; El-Shafie, Ahmed; Mirzaei, Majid; Galavi, Hadi; Mukhlisin, Muhammad; Jaafar, Othman

    2014-01-01

    Water level forecasting is an essential topic in water management affecting reservoir operations and decision making. Recently, modern methods utilizing artificial intelligence, fuzzy logic, and combinations of these techniques have been used in hydrological applications because of their considerable ability to map an input-output pattern without requiring prior knowledge of the criteria influencing the forecasting procedure. The artificial neurofuzzy interface system (ANFIS) is one of the most accurate models used in water resource management. Because the membership functions (MFs) possess the characteristics of smoothness and mathematical components, each set of input data is able to yield the best result using a certain type of MF in the ANFIS models. The objective of this study is to define the different ANFIS model by applying different types of MFs for each type of input to forecast the water level in two case studies, the Klang Gates Dam and Rantau Panjang station on the Johor river in Malaysia, to compare the traditional ANFIS model with the new introduced one in two different situations, reservoir and stream, showing the new approach outweigh rather than the traditional one in both case studies. This objective is accomplished by evaluating the model fitness and performance in daily forecasting.

  4. Target Price Accuracy

    Directory of Open Access Journals (Sweden)

    Alexander G. Kerl

    2011-04-01

    Full Text Available This study analyzes the accuracy of forecasted target prices within analysts’ reports. We compute a measure for target price forecast accuracy that evaluates the ability of analysts to exactly forecast the ex-ante (unknown 12-month stock price. Furthermore, we determine factors that explain this accuracy. Target price accuracy is negatively related to analyst-specific optimism and stock-specific risk (measured by volatility and price-to-book ratio. However, target price accuracy is positively related to the level of detail of each report, company size and the reputation of the investment bank. The potential conflicts of interests between an analyst and a covered company do not bias forecast accuracy.

  5. Evaluation of accuracy of complete-arch multiple-unit abutment-level dental implant impressions using different impression and splinting materials.

    Science.gov (United States)

    Buzayan, Muaiyed; Baig, Mirza Rustum; Yunus, Norsiah

    2013-01-01

    This in vitro study evaluated the accuracy of multiple-unit dental implant casts obtained from splinted or nonsplinted direct impression techniques using various splinting materials by comparing the casts to the reference models. The effect of two different impression materials on the accuracy of the implant casts was also evaluated for abutment-level impressions. A reference model with six internal-connection implant replicas placed in the completely edentulous mandibular arch and connected to multi-base abutments was fabricated from heat-curing acrylic resin. Forty impressions of the reference model were made, 20 each with polyether (PE) and polyvinylsiloxane (PVS) impression materials using the open tray technique. The PE and PVS groups were further subdivided into four subgroups of five each on the bases of splinting type: no splinting, bite registration PE, bite registration addition silicone, or autopolymerizing acrylic resin. The positional accuracy of the implant replica heads was measured on the poured casts using a coordinate measuring machine to assess linear differences in interimplant distances in all three axes. The collected data (linear and three-dimensional [3D] displacement values) were compared with the measurements calculated on the reference resin model and analyzed with nonparametric tests (Kruskal-Wallis and Mann-Whitney). No significant differences were found between the various splinting groups for both PE and PVS impression materials in terms of linear and 3D distortions. However, small but significant differences were found between the two impression materials (PVS, 91 μm; PE, 103 μm) in terms of 3D discrepancies, irrespective of the splinting technique employed. Casts obtained from both impression materials exhibited differences from the reference model. The impression material influenced impression inaccuracy more than the splinting material for multiple-unit abutment-level impressions.

  6. Exploring the Impact of Visual Complexity Levels in 3d City Models on the Accuracy of Individuals' Orientation and Cognitive Maps

    Science.gov (United States)

    Rautenbach, V.; Çöltekin, A.; Coetzee, S.

    2015-08-01

    In this paper we report results from a qualitative user experiment (n=107) designed to contribute to understanding the impact of various levels of complexity (mainly based on levels of detail, i.e., LoD) in 3D city models, specifically on the participants' orientation and cognitive (mental) maps. The experiment consisted of a number of tasks motivated by spatial cognition theory where participants (among other things) were given orientation tasks, and in one case also produced sketches of a path they `travelled' in a virtual environment. The experiments were conducted in groups, where individuals provided responses on an answer sheet. The preliminary results based on descriptive statistics and qualitative sketch analyses suggest that very little information (i.e., a low LoD model of a smaller area) might have a negative impact on the accuracy of cognitive maps constructed based on a virtual experience. Building an accurate cognitive map is an inherently desired effect of the visualizations in planning tasks, thus the findings are important for understanding how to develop better-suited 3D visualizations such as 3D city models. In this study, we specifically discuss the suitability of different levels of visual complexity for development planning (urban planning), one of the domains where 3D city models are most relevant.

  7. Comparison of predictive accuracy of pre surgical serum parathormone (PTH) level with that of parathyroid scan in case of primary hyperparathyroidism

    International Nuclear Information System (INIS)

    Nasreen, F.; Yasmeen, S.; Ahsan, A.S.M.; Mandal, T.; Sultana, K.S.A.; Shirin, A.

    2007-01-01

    Full text: Aims and Objective: Parathyroid scintigraphy with Tc-99m Sestamibi is a sensitive and specific test for pre operative localization of parathyroid adenoma (PA) in patients with primary hyperparathyroidism. However false ve studies are not uncommon. Our aim was to find out the predictive accuracy of pre surgical parathormone (PTH) level with that of parathyroid scan in case of primary hyperparathyroidism. Materials And Method: A total of 54 patients (29 male, 25 female) with a mean age of 41. 24+14.26 years suspected of primary hyperparathyroidism were included in this study. All patients had serum PTH and calcium level higher than the normal limit. Parathyroid scintigraphy was done by subtraction method using 185 MBq of Tc-99m PO4 which was given first and images were taken by planar gamma camera after 20 minutes followed by Tc-99m Sestamibi (740MBq) injection without moving the patient. We calculated the sensitivity and specificity at different cut off values of PTH such as >70pg/ml, >80pg/ml, >90pg/ml and >100pg/ml and observed the changes in sensitivity, specificity, PPV and NPV against scintigraphic diagnosis of PA. Result: Parathyroid scintigraphy revealed 15 positive cases (27.8%) amongst 54 patients, which were surgically proven to be so. The sensitivity of PTH in predicting positive parathyroid scan revealed to be 86.7% at serum PTH level of 70-90pg/ml. Then the sensitivity declines steadily to 73.3% at PTH level of >100pg/ml. The specificity increases gradually from 20.5% at serum PTH level >70pg/ml to 53.8% at serum PTH level >100pg/ml. However, PPV and NPV of serum PTH did not experience significant change like sensitivity and specificity with the increase of cut off values. Conclusion: We can use a cut off value of pre surgical serum PTH level at 90pg/ml before doing parathyroid scan as this has maximum sensitivity and optimum specificity. It will help to predict the outcome of scan and avoid unnecessary parathyroid scan and false ve cases

  8. Comparing Accuracy of Airborne Laser Scanning and TerraSAR-X Radar Images in the Estimation of Plot-Level Forest Variables

    Directory of Open Access Journals (Sweden)

    Juha Hyyppä

    2010-01-01

    Full Text Available In this study we compared the accuracy of low-pulse airborne laser scanning (ALS data, multi-temporal high-resolution noninterferometric TerraSAR-X radar data and a combined feature set derived from these data in the estimation of forest variables at plot level. The TerraSAR-X data set consisted of seven dual-polarized (HH/HV or VH/VV Stripmap mode images from all seasons of the year. We were especially interested in distinguishing between the tree species. The dependent variables estimated included mean volume, basal area, mean height, mean diameter and tree species-specific mean volumes. Selection of best possible feature set was based on a genetic algorithm (GA. The nonparametric k-nearest neighbour (k-NN algorithm was applied to the estimation. The research material consisted of 124 circular plots measured at tree level and located in the vicinity of Espoo, Finland. There are large variations in the elevation and forest structure in the study area, making it demanding for image interpretation. The best feature set contained 12 features, nine of them originating from the ALS data and three from the TerraSAR-X data. The relative RMSEs for the best performing feature set were 34.7% (mean volume, 28.1% (basal area, 14.3% (mean height, 21.4% (mean diameter, 99.9% (mean volume of Scots pine, 61.6% (mean volume of Norway spruce and 91.6% (mean volume of deciduous tree species. The combined feature set outperformed an ALS-based feature set marginally; in fact, the latter was better in the case of species-specific volumes. Features from TerraSAR-X alone performed poorly. However, due to favorable temporal resolution, satellite-borne radar imaging is a promising data source for updating large-area forest inventories based on low-pulse ALS.

  9. Evaluating IMRT and VMAT dose accuracy: Practical examples of failure to detect systematic errors when applying a commonly used metric and action levels

    Energy Technology Data Exchange (ETDEWEB)

    Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Chan, Maria F. [Memorial Sloan-Kettering Cancer Center, Basking Ridge, New Jersey 07920 (United States); Jarry, Geneviève; Lemire, Matthieu [Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4 (Canada); Lowden, John [Indiana University Health - Goshen Hospital, Goshen, Indiana 46526 (United States); Hampton, Carnell [Levine Cancer Institute/Carolinas Medical Center, Concord, North Carolina 28025 (United States); Feygelman, Vladimir [Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2013-11-15

    Purpose: This study (1) examines a variety of real-world cases where systematic errors were not detected by widely accepted methods for IMRT/VMAT dosimetric accuracy evaluation, and (2) drills-down to identify failure modes and their corresponding means for detection, diagnosis, and mitigation. The primary goal of detailing these case studies is to explore different, more sensitive methods and metrics that could be used more effectively for evaluating accuracy of dose algorithms, delivery systems, and QA devices.Methods: The authors present seven real-world case studies representing a variety of combinations of the treatment planning system (TPS), linac, delivery modality, and systematic error type. These case studies are typical to what might be used as part of an IMRT or VMAT commissioning test suite, varying in complexity. Each case study is analyzed according to TG-119 instructions for gamma passing rates and action levels for per-beam and/or composite plan dosimetric QA. Then, each case study is analyzed in-depth with advanced diagnostic methods (dose profile examination, EPID-based measurements, dose difference pattern analysis, 3D measurement-guided dose reconstruction, and dose grid inspection) and more sensitive metrics (2% local normalization/2 mm DTA and estimated DVH comparisons).Results: For these case studies, the conventional 3%/3 mm gamma passing rates exceeded 99% for IMRT per-beam analyses and ranged from 93.9% to 100% for composite plan dose analysis, well above the TG-119 action levels of 90% and 88%, respectively. However, all cases had systematic errors that were detected only by using advanced diagnostic techniques and more sensitive metrics. The systematic errors caused variable but noteworthy impact, including estimated target dose coverage loss of up to 5.5% and local dose deviations up to 31.5%. Types of errors included TPS model settings, algorithm limitations, and modeling and alignment of QA phantoms in the TPS. Most of the errors were

  10. VLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy. Orbital architecture analysis with PyAstrOFit

    Science.gov (United States)

    Wertz, O.; Absil, O.; Gómez González, C. A.; Milli, J.; Girard, J. H.; Mawet, D.; Pueyo, L.

    2017-02-01

    Context. HR8799 is orbited by at least four giant planets, making it a prime target for the recently commissioned Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT/SPHERE). As such, it was observed on five consecutive nights during the SPHERE science verification in December 2014. Aims: We aim to take full advantage of the SPHERE capabilities to derive accurate astrometric measurements based on H-band images acquired with the Infra-Red Dual-band Imaging and Spectroscopy (IRDIS) subsystem, and to explore the ultimate astrometric performance of SPHERE in this observing mode. We also aim to present a detailed analysis of the orbital parameters for the four planets. Methods: We performed thorough post-processing of the IRDIS images with the Vortex Imaging Processing (VIP) package to derive a robust astrometric measurement for the four planets. This includes the identification and careful evaluation of the different contributions to the error budget, including systematic errors. Combining our astrometric measurements with the ones previously published in the literature, we constrain the orbital parameters of the four planets using PyAstrOFit, our new open-source python package dedicated to orbital fitting using Bayesian inference with Monte-Carlo Markov Chain sampling. Results: We report the astrometric positions for epoch 2014.93 with an accuracy down to 2.0 mas, mainly limited by the astrometric calibration of IRDIS. For each planet, we derive the posterior probability density functions for the six Keplerian elements and identify sets of highly probable orbits. For planet d, there is clear evidence for nonzero eccentricity (e 0.35), without completely excluding solutions with smaller eccentricities. The three other planets are consistent with circular orbits, although their probability distributions spread beyond e = 0.2, and show a peak at e ≃ 0.1 for planet e. The four planets have consistent inclinations of approximately 30° with respect to the sky

  11. Light propagation in the gravitational field of N arbitrarily moving bodies in the 1.5PN approximation for high-precision astrometry

    Science.gov (United States)

    Zschocke, Sven

    2016-05-01

    High-precision astrometry on sub-micro-arcsecond level in angular resolution requires accurate determination of the trajectory of a light-signal from the celestial light source through the gravitational field of the Solar System toward the observer. In this investigation the light trajectory in the gravitational field of N moving bodies is determined in the 1.5 post-Newtonian approximation. In the approach presented two specific issues of particular importance are accounted for: (1) According to the recommendations of International Astronomical Union, the metric of the Solar System is expressed in terms of intrinsic mass-multipoles and intrinsic spin-multipoles of the massive bodies, allowing for arbitrary shape, inner structure and rotational motion of the massive bodies of the Solar System. (2) The Solar System bodies move along arbitrary world lines which can later be specified by Solar System ephemeris. The presented analytical solution for light trajectory is a primary requirement for extremely high-precision astrometry on sub-micro-arcsecond level of accuracy and associated massive computations in astrometric data reduction. An estimation of the numerical magnitude for time delay and light deflection of the leading multipoles is given.

  12. Dual cesium and rubidium atomic fountain with a 10{sup -16} level accuracy and applications; Fontaine atomique double de cesium et de rubidium avec une exactitude de quelques 10{sup -16} et applications

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet, F

    2008-05-15

    Atomic fountains are the most accomplished development of the atomic clocks based on the cesium atom whose hyperfine resonance defines the SI second since 1967. Today these systems are among those which realize the second with the best accuracy. We present the last developments of the cold cesium and rubidium atom dual fountain experiment at LNE-SYRTE. This unique dual setup would allow to obtain an outstanding resolution in fundamental physics tests based on atomic transition frequency comparisons. In order to enable operation with both atomic species simultaneously, we designed, tested and implemented on the fountain new collimators which combine the laser lights corresponding to each atom. By comparing our rubidium fountain to another cesium fountain over a decade, we performed a test of the stability of the fine structure constant at the level of 5 * 10{sup -16} per year. We carried on the work on the clock accuracy and we focused on the phase gradients effects in the interrogation cavity and on the microwave leakage. The fountain accuracy has been evaluated to 4 * 10{sup -16} for the cesium clock and to 5 * 10{sup -16} for the refurbished rubidium clock. As a powerful instrument of metrology, our fountain was implicated in many clock comparisons and contributed many times to calibrate the International Atomic Time. Furthermore, we used the fountain to perform a new test of Lorentz local invariance. (author)

  13. IMPROVING THE ACCURACY OF EXTRACTING SURFACE WATER QUALITY LEVELS (SWQLs USING REMOTE SENSING AND ARTIFICIAL NEURAL NETWORK: A CASE STUDY IN THE SAINT JOHN RIVER, CANADA

    Directory of Open Access Journals (Sweden)

    E. Sharaf El Din

    2017-09-01

    Full Text Available Delineating accurate surface water quality levels (SWQLs always presents a great challenge to researchers. Existing methods of assessing surface water quality only provide individual concentrations of monitoring stations without providing the overall SWQLs. Therefore, the results of existing methods are usually difficult to be understood by decision-makers. Conversely, the water quality index (WQI can simplify surface water quality assessment process to be accessible to decision-makers. However, in most cases, the WQI reflects inaccurate SWQLs due to the lack of representative water samples. It is very challenging to provide representative water samples because this process is costly and time consuming. To solve this problem, we introduce a cost-effective method which combines the Landsat-8 imagery and artificial intelligence to develop models to derive representative water samples by correlating concentrations of ground truth water samples to satellite spectral information. Our method was validated and the correlation between concentrations of ground truth water samples and predicted concentrations from the developed models reached a high level of coefficient of determination (R2 > 0.80, which is trustworthy. Afterwards, the predicted concentrations over each pixel of the study area were used as an input to the WQI developed by the Canadian Council of Ministers of the Environment to extract accurate SWQLs, for drinking purposes, in the Saint John River. The results indicated that SWQL was observed as 67 (Fair and 59 (Marginal for the lower and middle basins of the river, respectively. These findings demonstrate the potential of using our approach in surface water quality management.

  14. Improving the Accuracy of Extracting Surface Water Quality Levels (SWQLs) Using Remote Sensing and Artificial Neural Network: a Case Study in the Saint John River, Canada

    Science.gov (United States)

    Sammartano, G.; Spanò, A.

    2017-09-01

    Delineating accurate surface water quality levels (SWQLs) always presents a great challenge to researchers. Existing methods of assessing surface water quality only provide individual concentrations of monitoring stations without providing the overall SWQLs. Therefore, the results of existing methods are usually difficult to be understood by decision-makers. Conversely, the water quality index (WQI) can simplify surface water quality assessment process to be accessible to decision-makers. However, in most cases, the WQI reflects inaccurate SWQLs due to the lack of representative water samples. It is very challenging to provide representative water samples because this process is costly and time consuming. To solve this problem, we introduce a cost-effective method which combines the Landsat-8 imagery and artificial intelligence to develop models to derive representative water samples by correlating concentrations of ground truth water samples to satellite spectral information. Our method was validated and the correlation between concentrations of ground truth water samples and predicted concentrations from the developed models reached a high level of coefficient of determination (R2) > 0.80, which is trustworthy. Afterwards, the predicted concentrations over each pixel of the study area were used as an input to the WQI developed by the Canadian Council of Ministers of the Environment to extract accurate SWQLs, for drinking purposes, in the Saint John River. The results indicated that SWQL was observed as 67 (Fair) and 59 (Marginal) for the lower and middle basins of the river, respectively. These findings demonstrate the potential of using our approach in surface water quality management.

  15. Magnetic resonance imaging and magnetic resonance arthrography of the shoulder: dependence on the level of training of the performing radiologist for diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Theodoropoulos, John S. [University of Toronto, Division of Orthopaedics, Mount Sinai Hospital and the University Health Network, Toronto, ON (Canada); Andreisek, Gustav [University of Toronto, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, Toronto, ON (Canada); University Hospital Zuerich, Institute for Diagnostic Radiology, Zuerich (Switzerland); Harvey, Edward J. [McGill University, Division of Orthopaedics, MUHC - Montreal General Hospital, Montreal, Quebec (Canada); Wolin, Preston [Center for Athletic Medicine, Chicago, IL (United States)

    2010-07-15

    Discrepancies were identified between magnetic resonance (MR) imaging and clinical findings in patients who had MR imaging examinations evaluated by community-based general radiologists. The purpose of this study was to evaluate the diagnostic performance of MR imaging examinations of the shoulder with regard to the training level of the performing radiologist. A review of patient charts identified 238 patients (male/female, 175/63; mean age, 40.4 years) in whom 250 arthroscopies were performed and who underwent MR imaging or direct MR arthrography in either a community-based or hospital-based institution prior to surgery. All MR imaging and surgical reports were reviewed and the diagnostic performance for the detection of labral, rotator cuff, biceps, and Hill-Sachs lesions was determined. Kappa and Student's t test analyses were performed in a subset of cases in which initial community-based MR images were re-evaluated by hospital-based musculoskeletal radiologists, to determine the interobserver agreement and any differences in image interpretation. The diagnostic performance of community-based general radiologists was lower than that of hospital-based sub-specialized musculoskeletal radiologists. A sub-analysis of re-evaluated cases showed that musculoskeletal radiologists performed better. {kappa} values were 0.208, 0.396, 0.376, and 0.788 for labral, rotator cuff, biceps, and Hill-Sachs lesions (t test statistics: p =<0.001, 0.004, 0.019, and 0.235). Our results indicate that the diagnostic performance of MR imaging and MR arthrography of the shoulder depends on the training level of the performing radiologist, with sub-specialized musculoskeletal radiologists having a better diagnostic performance than general radiologists. (orig.)

  16. Trait Perception Accuracy and Acquaintance Within Groups: Tracking Accuracy Development.

    Science.gov (United States)

    Brown, Jill A; Bernieri, Frank

    2017-05-01

    Previous work on trait perception has evaluated accuracy at discrete stages of relationships (e.g., strangers, best friends). A relatively limited body of literature has investigated changes in accuracy as acquaintance within a dyad or group increases. Small groups of initially unacquainted individuals spent more than 30 hr participating in a wide range of activities designed to represent common interpersonal contexts (e.g., eating, traveling). We calculated how accurately each participant judged others in their group on the big five traits across three distinct points within the acquaintance process: zero acquaintance, after a getting-to-know-you conversation, and after 10 weeks of interaction and activity. Judgments of all five traits exhibited accuracy above chance levels after 10 weeks. An examination of the trait rating stability revealed that much of the revision in judgments occurred not over the course of the 10-week relationship as suspected, but between zero acquaintance and the getting-to-know-you conversation.

  17. Genetic structure of different cat populations in Europe and South America at a microgeographic level: importance of the choice of an adequate sampling level in the accuracy of population genetics interpretations

    Directory of Open Access Journals (Sweden)

    Manuel Ruiz-Garcia

    1999-12-01

    Full Text Available The phenotypic markers, coat color, pattern and hair length, of natural domestic cat populations observed in four cities (Barcelona, Catalonia; Palma Majorca, Balearic Islands; Rimini, Italy and Buenos Aires, Argentina were studied at a microgeographical level. Various population genetics techniques revealed that the degree of genetic differentiation between populations of Felis catus within these cities is relatively low, when compared with that found between populations of other mammals. Two different levels of sampling were used. One was that of "natural" colonies of cat families living together in specific points within the cities, and the other referred to "artificial" subpopulations, or groups of colonies, inhabiting the same district within a city. For the two sampling levels, some of the results were identical: 1 little genic heterogeneity, 2 existence of panmixia, 3 similar levels of expected heterozygosity in all populations analyzed, 4 no spatial autocorrelation, with certain differentiation in the Buenos Aires population compared to the others, and 5 very high correlations between colonies and subpopulations with the first factors from a Q factor analysis. Nevertheless, other population genetic statistics were greatly affected by the differential choice of sampling level. This was the case for: 1 the amount of heterogeneity of the FST and GST statistics between the cities, which was greater at the subpopulation level than at colony level, 2 the existence of correlations between genic differentiation statistics and size variables at subpopulation level, but not at the colony level, and 3 the relationships between the genetic variables and the principal factors of the R factorial analysis. This suggests that care should be taken in the choice of the sampling unit, for inferences on population genetics to be valid at the microgeographical level.Os marcadores fenotípicos cor da pelagem, padrão e comprimento dos pelos de popula

  18. Measurement of serum isoform [-2]proPSA derivatives shows superior accuracy to magnetic resonance imaging in the diagnosis of prostate cancer in patients with a total prostate-specific antigen level of 2-10 ng/ml.

    Science.gov (United States)

    Furuya, Kazuhiro; Kawahara, Takashi; Narahara, Masaki; Tokita, Takashi; Fukui, Sachi; Imano, Masashi; Mitome, Taku; Ito, Yusuke; Izumi, Koji; Osaka, Kimito; Yokomizo, Yumiko; Hayashi, Narihiko; Hasumi, Hisashi; Nawata, Shintaro; Kawano, Tsuyoshi; Yao, Masahiro; Uemura, Hiroji

    2017-08-01

    More accurate diagnostic procedures for prostate cancer are needed to avoid unnecessary biopsy due to the low specificity of prostate-specific antigen (PSA). Recent studies showed that the percentage of serum isoform [-2]proPSA (p2PSA) to free PSA (%p2PSA), the Prostate Health Index (PHI) and magnetic resonance imaging (MRI) were more accurate than PSA. The aim of this study was to test the accuracy of %p2PSA, PHI and MRI in discriminating patients with and without prostate cancer. The subjects were 50 consecutive men with a PSA level of 2.0-10.0 ng/ml, who underwent prostate biopsy from October 2012 to July 2014. These patients underwent multiparametric MRI before biopsy, and their serum samples were measured for PSA, free PSA and p2PSA. The sensitivity, specificity and accuracy of PHI, %p2PSA and MRI were compared with PSA in the diagnosis of biopsy-confirmed prostate cancer. In a univariate analysis, %p2PSA [area under the curve (AUC): 0.811] and PHI (AUC 0.795) were more accurate than MRI (AUC: 0.583) and PSA (AUC: 0.554) for prostate cancer detection. At 60% sensitivity, the specificity of PHI (76.5%) was higher than that of MRI (52.9%). For significant cancer detection, %p2PSA (AUC: 0.745), PHI (AUC: 0.791) and MRI (AUC: 0.739) were marginally more accurate than PSA (AUC: 0.696). At 85% sensitivity, the specificity of MRI (62.1%) was higher than that of PHI (34.5%). PHI and %p2PSA can be used for screening the general population and MRI can be used for detection of significant cancer in patients suspected, from screening tests, of having prostate cancer.

  19. Diagnosing Eyewitness Accuracy

    OpenAIRE

    Russ, Andrew

    2015-01-01

    Eyewitnesses frequently mistake innocent people for the perpetrator of an observed crime. Such misidentifications have led to the wrongful convictions of many people. Despite this, no reliable method yet exists to determine eyewitness accuracy. This thesis explored two new experimental methods for this purpose. Chapter 2 investigated whether repetition priming can measure prior exposure to a target and compared this with observers’ explicit eyewitness accuracy. Across three experiments slower...

  20. Social Security Administration Data for Enumeration Accuracy

    Data.gov (United States)

    Social Security Administration — This dataset provides data at the national level from federal fiscal year 2006 onwards for the accuracy of the assignment of Social Security numbers (SSN) based on...

  1. Overlay accuracy fundamentals

    Science.gov (United States)

    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 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.

  2. Improving shuffler assay accuracy

    International Nuclear Information System (INIS)

    Rinard, P.M.

    1995-01-01

    Drums of uranium waste should be disposed of in an economical and environmentally sound manner. The most accurate possible assays of the uranium masses in the drums are required for proper disposal. The accuracies of assays from a shuffler are affected by the type of matrix material in the drums. Non-hydrogenous matrices have little effect on neutron transport and accuracies are very good. If self-shielding is known to be a minor problem, good accuracies are also obtained with hydrogenous matrices when a polyethylene sleeve is placed around the drums. But for those cases where self-shielding may be a problem, matrices are hydrogenous, and uranium distributions are non-uniform throughout the drums, the accuracies are degraded. They can be greatly improved by determining the distributions of the uranium and then applying correction factors based on the distributions. This paper describes a technique for determining uranium distributions by using the neutron count rates in detector banks around the waste drum and solving a set of overdetermined linear equations. Other approaches were studied to determine the distributions and are described briefly. Implementation of this correction is anticipated on an existing shuffler next year

  3. Enhancing spoken connected-digit recognition accuracy by error ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    nition systems have gained acceptable accuracy levels, the accuracy of recognition of current connected ... bar code and ISBN1 library code to name a few. ..... Kopec G, Bush M 1985 Network-based connected-digit recognition. IEEE Trans.

  4. Geoid undulation accuracy

    Science.gov (United States)

    Rapp, Richard H.

    1993-01-01

    The determination of the geoid and equipotential surface of the Earth's gravity field, has long been of interest to geodesists and oceanographers. The geoid provides a surface to which the actual ocean surface can be compared with the differences implying information on the circulation patterns of the oceans. For use in oceanographic applications the geoid is ideally needed to a high accuracy and to a high resolution. There are applications that require geoid undulation information to an accuracy of +/- 10 cm with a resolution of 50 km. We are far from this goal today but substantial improvement in geoid determination has been made. In 1979 the cumulative geoid undulation error to spherical harmonic degree 20 was +/- 1.4 m for the GEM10 potential coefficient model. Today the corresponding value has been reduced to +/- 25 cm for GEM-T3 or +/- 11 cm for the OSU91A model. Similar improvements are noted by harmonic degree (wave-length) and in resolution. Potential coefficient models now exist to degree 360 based on a combination of data types. This paper discusses the accuracy changes that have taken place in the past 12 years in the determination of geoid undulations.

  5. Circulating irisin levels are lower in patients with either stable coronary artery disease (CAD) or myocardial infarction (MI) versus healthy controls, whereas follistatin and activin A levels are higher and can discriminate MI from CAD with similar to CK-MB accuracy.

    Science.gov (United States)

    Anastasilakis, Athanasios D; Koulaxis, Dimitrios; Kefala, Nikoleta; Polyzos, Stergios A; Upadhyay, Jagriti; Pagkalidou, Eirini; Economou, Fotios; Anastasilakis, Chrysostomos D; Mantzoros, Christos S

    2017-08-01

    Several myokines are produced by cardiac muscle. We investigated changes in myokine levels at the time of acute myocardial infarction (MI) and following reperfusion in relation to controls. Patients with MI (MI Group, n=31) treated with percutaneous coronary intervention (PCI) were compared to patients with stable coronary artery disease (CAD) subjected to scheduled PCI (CAD Group, n=40) and controls with symptoms mimicking CAD without stenosis in angiography (Control Group, n=43). The number and degree of stenosis were recorded. Irisin, follistatin, follistatin-like 3, activin A and B, ALT, AST, CK and CK-MB were measured at baseline and 6 or 24h after the intervention. MI and CAD patients had lower irisin than controls (p<0.001). MI patients had higher follistatin, activin A, CK, CK-MB and AST than CAD patients and controls (all p≤0.001). None of the myokines changed following reperfusion. Circulating irisin was associated with the degree of stenosis in all patients (p=0.05). Irisin was not inferior to CK-MB in predicting MI while folistatin and activin A could discriminate MI from CAD patients with similar to CK-MB accuracy. None of these myokines was altered following PCI in contrast to CK-MB. Irisin levels are lower in MI and CAD implying that their production may depend on myocadial blood supply. Follistatin and activin A are higher in MI than in CAD suggesting increased release due to myocardial necrosis. They can predict MI with accuracy similar to CK-MB and their role in the diagnosis of MI remains to be confirmed by prospective large clinical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Systematic review of discharge coding accuracy

    Science.gov (United States)

    Burns, E.M.; Rigby, E.; Mamidanna, R.; Bottle, A.; Aylin, P.; Ziprin, P.; Faiz, O.D.

    2012-01-01

    Introduction Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain. Methods Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries. Results Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3–92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3–94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7–88.7%). There was considerable variation in accuracy rates between studies (50.5–97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3–92.1%) to 96.0% (IQR: 89.3–96.3), P= 0.020. Conclusion Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making. PMID:21795302

  7. Meditation experience predicts introspective accuracy.

    Directory of Open Access Journals (Sweden)

    Kieran C R Fox

    Full Text Available The accuracy of subjective reports, especially those involving introspection of one's own internal processes, remains unclear, and research has demonstrated large individual differences in introspective accuracy. It has been hypothesized that introspective accuracy may be heightened in persons who engage in meditation practices, due to the highly introspective nature of such practices. We undertook a preliminary exploration of this hypothesis, examining introspective accuracy in a cross-section of meditation practitioners (1-15,000 hrs experience. Introspective accuracy was assessed by comparing subjective reports of tactile sensitivity for each of 20 body regions during a 'body-scanning' meditation with averaged, objective measures of tactile sensitivity (mean size of body representation area in primary somatosensory cortex; two-point discrimination threshold as reported in prior research. Expert meditators showed significantly better introspective accuracy than novices; overall meditation experience also significantly predicted individual introspective accuracy. These results suggest that long-term meditators provide more accurate introspective reports than novices.

  8. Improving coding accuracy in an academic practice.

    Science.gov (United States)

    Nguyen, Dana; O'Mara, Heather; Powell, Robert

    2017-01-01

    Practice management has become an increasingly important component of graduate medical education. This applies to every practice environment; private, academic, and military. One of the most critical aspects of practice management is documentation and coding for physician services, as they directly affect the financial success of any practice. Our quality improvement project aimed to implement a new and innovative method for teaching billing and coding in a longitudinal fashion in a family medicine residency. We hypothesized that implementation of a new teaching strategy would increase coding accuracy rates among residents and faculty. Design: single group, pretest-posttest. military family medicine residency clinic. Study populations: 7 faculty physicians and 18 resident physicians participated as learners in the project. Educational intervention: monthly structured coding learning sessions in the academic curriculum that involved learner-presented cases, small group case review, and large group discussion. overall coding accuracy (compliance) percentage and coding accuracy per year group for the subjects that were able to participate longitudinally. Statistical tests used: average coding accuracy for population; paired t test to assess improvement between 2 intervention periods, both aggregate and by year group. Overall coding accuracy rates remained stable over the course of time regardless of the modality of the educational intervention. A paired t test was conducted to compare coding accuracy rates at baseline (mean (M)=26.4%, SD=10%) to accuracy rates after all educational interventions were complete (M=26.8%, SD=12%); t24=-0.127, P=.90. Didactic teaching and small group discussion sessions did not improve overall coding accuracy in a residency practice. Future interventions could focus on educating providers at the individual level.

  9. Test Expectancy Affects Metacomprehension Accuracy

    Science.gov (United States)

    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…

  10. Improving the spatial accuracy in functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) effect: benefits from parallel imaging and a 32-channel head array coil at 1.5 Tesla.

    Science.gov (United States)

    Fellner, C; Doenitz, C; Finkenzeller, T; Jung, E M; Rennert, J; Schlaier, J

    2009-01-01

    Geometric distortions and low spatial resolution are current limitations in functional magnetic resonance imaging (fMRI). The aim of this study was to evaluate if application of parallel imaging or significant reduction of voxel size in combination with a new 32-channel head array coil can reduce those drawbacks at 1.5 T for a simple hand motor task. Therefore, maximum t-values (tmax) in different regions of activation, time-dependent signal-to-noise ratios (SNR(t)) as well as distortions within the precentral gyrus were evaluated. Comparing fMRI with and without parallel imaging in 17 healthy subjects revealed significantly reduced geometric distortions in anterior-posterior direction. Using parallel imaging, tmax only showed a mild reduction (7-11%) although SNR(t) was significantly diminished (25%). In 7 healthy subjects high-resolution (2 x 2 x 2 mm3) fMRI was compared with standard fMRI (3 x 3 x 3 mm3) in a 32-channel coil and with high-resolution fMRI in a 12-channel coil. The new coil yielded a clear improvement for tmax (21-32%) and SNR(t) (51%) in comparison with the 12-channel coil. Geometric distortions were smaller due to the smaller voxel size. Therefore, the reduction in tmax (8-16%) and SNR(t) (52%) in the high-resolution experiment seems to be tolerable with this coil. In conclusion, parallel imaging is an alternative to reduce geometric distortions in fMRI at 1.5 T. Using a 32-channel coil, reduction of the voxel size might be the preferable way to improve spatial accuracy.

  11. Charging Levels of Four tRNA Species in Escherichia coli Rel+ and REL- Strains during Amino Acid Starvation: A Simple Model for the Effect of ppGpp on Translational Accuracy

    DEFF Research Database (Denmark)

    Sørensen, M.A.

    2001-01-01

    Escherichia coli strains mutated in the relA gene lack the ability to produce ppGpp during amino acid starvation. One consequence of this deficiency is a tenfold increase in misincorporation at starved codons compared to the wild-type. Previous work had shown that the charging levels of tRNAs were...... the same in Rel+ and Rel- strains and reduced, at most, two- to fivefold in both strains during starvation. The present reinvestigation of the charging levels of tRNA2Arg, tRNA1Thr, tRNA1Leu and tRNAHis during starvation of isogenic Rel+ and Rel- strains showed that starvation reduced charging levels...... tenfold to 40-fold. This reduction corresponds much better with the decreased rate of protein synthesis during starvation than that reported earlier. The determination of the charging levels of tRNA2Arg and tRNA1Thr during starvation were accurate enough to demonstrate that charging levels were at least...

  12. Speed-Accuracy Tradeoffs in Speech Production

    Science.gov (United States)

    2017-06-01

    capacity of discrete motor responses under different cognitive sets. Journal of Experimental Psychology , 71 (4), 475. SPEED-ACCURACY TRADEOFFS IN HUMAN...space defined by vocal tract constriction degree and location, as in Articulatory Phonology Browman & Goldstein (1992). These high-level spaces are...relationship between speech gestures varies as a function of their positions within the syllable Browman & Goldstein (1995); Krakow (1999); Byrd et al

  13. Test expectancy affects metacomprehension accuracy.

    Science.gov (United States)

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

    2011-06-01

    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 practice tests. The purpose of the present study was to examine whether the accuracy metacognitive monitoring was affected by the nature of the test expected. Students (N= 59) were randomly assigned to one of two test expectancy groups (memory vs. inference). Then after reading texts, judging learning, completed both memory and inference tests. Test performance and monitoring accuracy were superior when students received the kind of test they had been led to expect rather than the unexpected test. Tests influence students' perceptions of what constitutes learning. Our findings suggest that this could affect how students prepare for tests and how they monitoring their own learning. ©2010 The British Psychological Society.

  14. 100% classification accuracy considered harmful: the normalized information transfer factor explains the accuracy paradox.

    Directory of Open Access Journals (Sweden)

    Francisco J Valverde-Albacete

    Full Text Available 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.

  15. FIELD ACCURACY TEST OF RPAS PHOTOGRAMMETRY

    Directory of Open Access Journals (Sweden)

    P. Barry

    2013-08-01

    Full Text Available Baseline Surveys Ltd is a company which specialises in the supply of accurate geospatial data, such as cadastral, topographic and engineering survey data to commercial and government bodies. Baseline Surveys Ltd invested in aerial drone photogrammetric technology and had a requirement to establish the spatial accuracy of the geographic data derived from our unmanned aerial vehicle (UAV photogrammetry before marketing our new aerial mapping service. Having supplied the construction industry with survey data for over 20 years, we felt that is was crucial for our clients to clearly understand the accuracy of our photogrammetry so they can safely make informed spatial decisions, within the known accuracy limitations of our data. This information would also inform us on how and where UAV photogrammetry can be utilised. What we wanted to find out was the actual accuracy that can be reliably achieved using a UAV to collect data under field conditions throughout a 2 Ha site. We flew a UAV over the test area in a "lawnmower track" pattern with an 80% front and 80% side overlap; we placed 45 ground markers as check points and surveyed them in using network Real Time Kinematic Global Positioning System (RTK GPS. We specifically designed the ground markers to meet our accuracy needs. We established 10 separate ground markers as control points and inputted these into our photo modelling software, Agisoft PhotoScan. The remaining GPS coordinated check point data were added later in ArcMap to the completed orthomosaic and digital elevation model so we could accurately compare the UAV photogrammetry XYZ data with the RTK GPS XYZ data at highly reliable common points. The accuracy we achieved throughout the 45 check points was 95% reliably within 41 mm horizontally and 68 mm vertically and with an 11.7 mm ground sample distance taken from a flight altitude above ground level of 90 m.The area covered by one image was 70.2 m × 46.4 m, which equals 0.325 Ha. This

  16. Forecast Accuracy Uncertainty and Momentum

    OpenAIRE

    Bing Han; Dong Hong; Mitch Warachka

    2009-01-01

    We demonstrate that stock price momentum and earnings momentum can result from uncertainty surrounding the accuracy of cash flow forecasts. Our model has multiple information sources issuing cash flow forecasts for a stock. The investor combines these forecasts into an aggregate cash flow estimate that has minimal mean-squared forecast error. This aggregate estimate weights each cash flow forecast by the estimated accuracy of its issuer, which is obtained from their past forecast errors. Mome...

  17. Social Power Increases Interoceptive Accuracy

    Directory of Open Access Journals (Sweden)

    Mehrad Moeini-Jazani

    2017-08-01

    Full Text Available Building on recent psychological research showing that power increases self-focused attention, we propose that having power increases accuracy in perception of bodily signals, a phenomenon known as interoceptive accuracy. Consistent with our proposition, participants in a high-power experimental condition outperformed those in the control and low-power conditions in the Schandry heartbeat-detection task. We demonstrate that the effect of power on interoceptive accuracy is not explained by participants’ physiological arousal, affective state, or general intention for accuracy. Rather, consistent with our reasoning that experiencing power shifts attentional resources inward, we show that the effect of power on interoceptive accuracy is dependent on individuals’ chronic tendency to focus on their internal sensations. Moreover, we demonstrate that individuals’ chronic sense of power also predicts interoceptive accuracy similar to, and independent of, how their situationally induced feeling of power does. We therefore provide further support on the relation between power and enhanced perception of bodily signals. Our findings offer a novel perspective–a psychophysiological account–on how power might affect judgments and behavior. We highlight and discuss some of these intriguing possibilities for future research.

  18. Diagnostic accuracy in virtual dermatopathology

    DEFF Research Database (Denmark)

    Mooney, E.; Kempf, W.; Jemec, G.B.E.

    2012-01-01

    Background Virtual microscopy is used for teaching medical students and residents and for in-training and certification examinations in the United States. However, no existing studies compare diagnostic accuracy using virtual slides and photomicrographs. The objective of this study was to compare...... diagnostic accuracy of dermatopathologists and pathologists using photomicrographs vs. digitized images, through a self-assessment examination, and to elucidate assessment of virtual dermatopathology. Methods Forty-five dermatopathologists and pathologists received a randomized combination of 15 virtual...... slides and photomicrographs with corresponding clinical photographs and information in a self-assessment examination format. Descriptive data analysis and comparison of groups were performed using a chi-square test. Results Diagnostic accuracy in dermatopathology using virtual dermatopathology...

  19. Teaching accuracy and reliability for student projects

    Science.gov (United States)

    Fisher, Nick

    2002-09-01

    Physics students at Rugby School follow the Salters Horners A-level course, which involves working on a two-week practical project of their own choosing. Pupils often misunderstand the concepts of accuracy and reliability, believing, for example, that repeating readings makes them more accurate and more reliable, whereas all it does is help to check repeatability. The course emphasizes the ideas of checking anomalous points, improving accuracy and making readings more sensitive. This article describes how we teach pupils in preparation for their projects. Based on many years of running such projects, much of this material is from a short booklet that we give out to pupils, when we train them in practical project skills.

  20. ACCURACY DIMENSIONS IN REMOTE SENSING

    Directory of Open Access Journals (Sweden)

    Á. Barsi

    2018-04-01

    Full Text Available The technological developments in remote sensing (RS during the past decade has contributed to a significant increase in the size of data user community. For this reason data quality issues in remote sensing face a significant increase in importance, particularly in the era of Big Earth data. Dozens of available sensors, hundreds of sophisticated data processing techniques, countless software tools assist the processing of RS data and contributes to a major increase in applications and users. In the past decades, scientific and technological community of spatial data environment were focusing on the evaluation of data quality elements computed for point, line, area geometry of vector and raster data. Stakeholders of data production commonly use standardised parameters to characterise the quality of their datasets. Yet their efforts to estimate the quality did not reach the general end-user community running heterogeneous applications who assume that their spatial data is error-free and best fitted to the specification standards. The non-specialist, general user group has very limited knowledge how spatial data meets their needs. These parameters forming the external quality dimensions implies that the same data system can be of different quality to different users. The large collection of the observed information is uncertain in a level that can decry the reliability of the applications. Based on prior paper of the authors (in cooperation within the Remote Sensing Data Quality working group of ISPRS, which established a taxonomy on the dimensions of data quality in GIS and remote sensing domains, this paper is aiming at focusing on measures of uncertainty in remote sensing data lifecycle, focusing on land cover mapping issues. In the paper we try to introduce how quality of the various combination of data and procedures can be summarized and how services fit the users’ needs. The present paper gives the theoretic overview of the issue, besides

  1. Accuracy Dimensions in Remote Sensing

    Science.gov (United States)

    Barsi, Á.; Kugler, Zs.; László, I.; Szabó, Gy.; Abdulmutalib, H. M.

    2018-04-01

    The technological developments in remote sensing (RS) during the past decade has contributed to a significant increase in the size of data user community. For this reason data quality issues in remote sensing face a significant increase in importance, particularly in the era of Big Earth data. Dozens of available sensors, hundreds of sophisticated data processing techniques, countless software tools assist the processing of RS data and contributes to a major increase in applications and users. In the past decades, scientific and technological community of spatial data environment were focusing on the evaluation of data quality elements computed for point, line, area geometry of vector and raster data. Stakeholders of data production commonly use standardised parameters to characterise the quality of their datasets. Yet their efforts to estimate the quality did not reach the general end-user community running heterogeneous applications who assume that their spatial data is error-free and best fitted to the specification standards. The non-specialist, general user group has very limited knowledge how spatial data meets their needs. These parameters forming the external quality dimensions implies that the same data system can be of different quality to different users. The large collection of the observed information is uncertain in a level that can decry the reliability of the applications. Based on prior paper of the authors (in cooperation within the Remote Sensing Data Quality working group of ISPRS), which established a taxonomy on the dimensions of data quality in GIS and remote sensing domains, this paper is aiming at focusing on measures of uncertainty in remote sensing data lifecycle, focusing on land cover mapping issues. In the paper we try to introduce how quality of the various combination of data and procedures can be summarized and how services fit the users' needs. The present paper gives the theoretic overview of the issue, besides selected, practice

  2. Cadastral Database Positional Accuracy Improvement

    Science.gov (United States)

    Hashim, N. M.; Omar, A. H.; Ramli, S. N. M.; Omar, K. M.; Din, N.

    2017-10-01

    Positional Accuracy Improvement (PAI) is the refining process of the geometry feature in a geospatial dataset to improve its actual position. This actual position relates to the absolute position in specific coordinate system and the relation to the neighborhood features. With the growth of spatial based technology especially Geographical Information System (GIS) and Global Navigation Satellite System (GNSS), the PAI campaign is inevitable especially to the legacy cadastral database. Integration of legacy dataset and higher accuracy dataset like GNSS observation is a potential solution for improving the legacy dataset. However, by merely integrating both datasets will lead to a distortion of the relative geometry. The improved dataset should be further treated to minimize inherent errors and fitting to the new accurate dataset. The main focus of this study is to describe a method of angular based Least Square Adjustment (LSA) for PAI process of legacy dataset. The existing high accuracy dataset known as National Digital Cadastral Database (NDCDB) is then used as bench mark to validate the results. It was found that the propose technique is highly possible for positional accuracy improvement of legacy spatial datasets.

  3. Classification Accuracy Is Not Enough

    DEFF Research Database (Denmark)

    Sturm, Bob L.

    2013-01-01

    A recent review of the research literature evaluating music genre recognition (MGR) systems over the past two decades shows that most works (81\\%) measure the capacity of a system to recognize genre by its classification accuracy. We show here, by implementing and testing three categorically...

  4. The hidden KPI registration accuracy.

    Science.gov (United States)

    Shorrosh, Paul

    2011-09-01

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

  5. Accuracy in Optical Information Processing

    Science.gov (United States)

    Timucin, Dogan Aslan

    Low computational accuracy is an important obstacle for optical processors which blocks their way to becoming a practical reality and a serious challenger for classical computing paradigms. This research presents a comprehensive solution approach to the problem of accuracy enhancement in discrete analog optical information processing systems. Statistical analysis of a generic three-plane optical processor is carried out first, taking into account the effects of diffraction, interchannel crosstalk, and background radiation. Noise sources included in the analysis are photon, excitation, and emission fluctuations in the source array, transmission and polarization fluctuations in the modulator, and photoelectron, gain, dark, shot, and thermal noise in the detector array. Means and mutual coherence and probability density functions are derived for both optical and electrical output signals. Next, statistical models for a number of popular optoelectronic devices are studied. Specific devices considered here are light-emitting and laser diode sources, an ideal noiseless modulator and a Gaussian random-amplitude-transmittance modulator, p-i-n and avalanche photodiode detectors followed by electronic postprocessing, and ideal free-space geometrical -optics propagation and single-lens imaging systems. Output signal statistics are determined for various interesting device combinations by inserting these models into the general formalism. Finally, based on these special-case output statistics, results on accuracy limitations and enhancement in optical processors are presented. Here, starting with the formulation of the accuracy enhancement problem as (1) an optimal detection problem and (2) as a parameter estimation problem, the potential accuracy improvements achievable via the classical multiple-hypothesis -testing and maximum likelihood and Bayesian parameter estimation methods are demonstrated. Merits of using proper normalizing transforms which can potentially stabilize

  6. Connecting VLBI and Gaia Celestial Reference Frames

    Energy Technology Data Exchange (ETDEWEB)

    Malkin, Zinovy, E-mail: malkin@gao.spb.ru [Department of Radio Astronomy Research, The Pulkovo Astronomical Observatory, St. Petersburg (Russian Federation); Institute of Earth Sciences, St. Petersburg State University, St. Petersburg (Russian Federation); Astronomy and Cosmic Geodesy Department, Kazan Federal University, Kazan (Russian Federation)

    2016-09-12

    The current state of the link problem between radio and optical celestial reference frames is considered. The main objectives of the investigations in this direction during the next few years are the preparation of a comparison and the mutual orientation and rotation between the optical Gaia Celestial Reference Frame (GCRF) and the 3rd generation radio International Celestial Reference Frame (ICRF3), obtained from VLBI observations. Both systems, ideally, should be a realization of the ICRS (International Celestial Reference System) at micro-arcsecond level accuracy. Therefore, the link accuracy between the ICRF and GCRF should be obtained with similar error level, which is not a trivial task due to relatively large systematic and random errors in source positions at different frequency bands. In this paper, a brief overview of recent work on the GCRF–ICRF link is presented. Additional possibilities to improve the GCRF–ICRF link accuracy are discussed. The suggestion is made to use astrometric radio sources with optical magnitude to 20{sup m} rather than to 18{sup m} as currently planned for the GCRF–ICRF link. In addition, the use of radio stars is also a prospective method to obtain independent and accurate orientation between the Gaia frame and the ICRF.

  7. Connecting VLBI and Gaia celestial reference frames

    Directory of Open Access Journals (Sweden)

    Zinovy Malkin

    2016-09-01

    Full Text Available The current state of the link problem between radio and optical celestial reference frames is considered.The main objectives of the investigations in this direction during the next few years are the preparation of a comparisonand the mutual orientation and rotation between the optical it Gaia Celestial Reference Frame (GCRFand the 3rd generation radio International Celestial Reference Frame (ICRF3, obtained from VLBI observations.Both systems, ideally, should be a realization of the ICRS (International Celestial Reference System at micro-arcsecond level accuracy.Therefore, the link accuracy between the ICRF and GCRF should be obtained with similar error level, which is not a trivial taskdue to relatively large systematic and random errors in source positions at different frequency bands.In this paper, a brief overview of recent work on the GCRF--ICRF link is presented.Additional possibilities to improve the GCRF--ICRF link accuracy are discussed.The suggestion is made to use astrometric radio sources with optical magnitude to 20$^m$ rather than to 18$^m$ as currently plannedfor the GCRF--ICRF link.In addition, the use of radio stars is also a prospective method to obtain independent and accurate orientation between the Gaia frame and the ICRF.

  8. Radioactivity analysis of food and accuracy control

    International Nuclear Information System (INIS)

    Ota, Tomoko

    2013-01-01

    From the fact that radioactive substances have been detected from the foods such as agricultural and livestock products and marine products due to the accident of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, the Ministry of Health, Labour and Welfare stipulated new standards geared to general foods on radioactive cesium by replacing the interim standards up to now. Various institutions began to measure radioactivity on the basis of this instruction, but as a new challenge, a problem of the reliability of the data occurred. Therefore, accuracy control to indicate the proof that the quality of the data can be retained at an appropriate level judging from an objective manner is important. In order to consecutively implement quality management activities, it is necessary for each inspection agency to build an accuracy control system. This paper introduces support service, as a new attempt, for establishing the accuracy control system. This service is offered jointly by three organizations, such as TUV Rheinland Japan Ltd., Japan Frozen Foods Inspection Corporation, and Japan Chemical Analysis Center. This service consists of the training of radioactivity measurement practitioners, proficiency test for radioactive substance measurement, and personal authentication. (O.A.)

  9. Valoración de la precisión del golpeo en jugadores de pádel en función de su nivel de juego. [Groundstroke accuracy assessment in padel players according to their level of play].

    Directory of Open Access Journals (Sweden)

    Bernardino Javier Sánchez-Alcaraz

    2016-07-01

    Full Text Available El objetivo de este trabajo fue valorar la precisión de diferentes golpes de pádel en una situación de juego prolongada y variada, estudiando las diferencias en función del nivel de juego de los jugadores. Se realizó un estudio sobre una muestra de 12 jugadores diestros masculinos (24.4 ± 6.5 años de edad, 175.9 ± 8.4 cm de altura, y 83.3 ± 8.7 kg de peso, clasificados en dos grupos en función de su nivel de juego: iniciación (n=6 y avanzados (n=6. Se diseñó un test para evaluar la precisión del golpeo de los jugadores, incluyendo la sucesión de cuatro golpes (bajada de pared de derecha, volea de derecha, bandeja, derecha de fondo realizados en ocho series de 30 segundos de duración, con 20 segundos de descanso entre series. Para valorar la precisión de los golpeos se delimitaron una serie de zonas objetivo (con diferentes puntuaciones donde la pelota debía botar para cada uno de los golpes. Se contabilizaron las puntuaciones obtenidas para cada tipo de golpe y en total, así como el número de golpeos realizados. Se registró, además, la frecuencia cardiaca (FC y la percepción individual del esfuerzo (RPE. Los resultados mostraron puntuaciones totales significativamente mayores para los jugadores de nivel avanzado realizando el mismo número de golpeos, especialmente en la derecha de fondo y en la bandeja. Aunque no se encontraron diferencias en los registros de FC, los valores de RPE fueron significativamente menores en los jugadores avanzados. Estos datos pueden resultar de utilidad para los técnicos de pádel y el diseño de los entrenamientos. Abstract The aim of this study was to assess the groundstroke accuracy in padel players depending of their level of play. A total of 12 right-handed male players (24.4 ± 6.5 years old, 175.9 ± 8.4 cm height, and 83.3 ± 8.7 kg weight participated in this study. The sample was divided into two groups according to their level of play: amateur (n=6 vs. advanced (n=6. We designed an

  10. High accuracy autonomous navigation using the global positioning system (GPS)

    Science.gov (United States)

    Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul

    1997-01-01

    The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.

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

    Science.gov (United States)

    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.

  12. Climate Change Accuracy: Requirements and Economic Value

    Science.gov (United States)

    Wielicki, B. A.; Cooke, R.; Mlynczak, M. G.; Lukashin, C.; Thome, K. J.; Baize, R. R.

    2014-12-01

    Higher than normal accuracy is required to rigorously observe decadal climate change. But what level is needed? How can this be quantified? This presentation will summarize a new more rigorous and quantitative approach to determining the required accuracy for climate change observations (Wielicki et al., 2013, BAMS). Most current global satellite observations cannot meet this accuracy level. A proposed new satellite mission to resolve this challenge is CLARREO (Climate Absolute Radiance and Refractivity Observatory). CLARREO is designed to achieve advances of a factor of 10 for reflected solar spectra and a factor of 3 to 5 for thermal infrared spectra (Wielicki et al., Oct. 2013 BAMS). The CLARREO spectrometers are designed to serve as SI traceable benchmarks for the Global Satellite Intercalibration System (GSICS) and to greatly improve the utility of a wide range of LEO and GEO infrared and reflected solar passive satellite sensors for climate change observations (e.g. CERES, MODIS, VIIIRS, CrIS, IASI, Landsat, SPOT, etc). Providing more accurate decadal change trends can in turn lead to more rapid narrowing of key climate science uncertainties such as cloud feedback and climate sensitivity. A study has been carried out to quantify the economic benefits of such an advance as part of a rigorous and complete climate observing system. The study concludes that the economic value is $12 Trillion U.S. dollars in Net Present Value for a nominal discount rate of 3% (Cooke et al. 2013, J. Env. Sys. Dec.). A brief summary of these two studies and their implications for the future of climate science will be presented.

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

    Directory of Open Access Journals (Sweden)

    Qingzhong Cai

    2016-06-01

    Full Text Available 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.

  14. Can Translation Improve EFL Students' Grammatical Accuracy? [

    Directory of Open Access Journals (Sweden)

    Carol Ebbert-Hübner

    2018-01-01

    Full Text Available This report focuses on research results from a project completed at Trier University in December 2015 that provides insight into whether a monolingual group of learners can improve their grammatical accuracy and reduce interference mistakes in their English via contrastive analysis and translation instruction and activities. Contrastive analysis and translation (CAT instruction in this setting focusses on comparing grammatical differences between students’ dominant language (German and English, and practice activities where sentences or short texts are translated from German into English. The results of a pre- and post-test administered in the first and final week of a translation class were compared to two other class types: a grammar class which consisted of form-focused instruction but not translation, and a process-approach essay writing class where students received feedback on their written work throughout the semester. The results of our study indicate that with C1 level EAP students, more improvement in grammatical accuracy is seen through teaching with CAT than in explicit grammar instruction or through language feedback on written work alone. These results indicate that CAT does indeed have a place in modern language classes.

  15. Data accuracy assessment using enterprise architecture

    Science.gov (United States)

    Närman, Per; Holm, Hannes; Johnson, Pontus; König, Johan; Chenine, Moustafa; Ekstedt, Mathias

    2011-02-01

    Errors in business processes result in poor data accuracy. This article proposes an architecture analysis method which utilises ArchiMate and the Probabilistic Relational Model formalism to model and analyse data accuracy. Since the resources available for architecture analysis are usually quite scarce, the method advocates interviews as the primary data collection technique. A case study demonstrates that the method yields correct data accuracy estimates and is more resource-efficient than a competing sampling-based data accuracy estimation method.

  16. Technical accuracy in historical writing

    International Nuclear Information System (INIS)

    Taylor, L.S.

    1981-01-01

    A guest editorial is presented on the question of accuracy in the writing of radiation protection history. The author has written several books and articles dealing with various aspects of the development of radiation protection standards and philosophy; some of his own minor errors which have been picked up and frequently repeated are confessed. The author also outlines some of the general faults he has encountered in other articles on the subject. A common complaint is that many writers give source references without checking back to the original sources which leads to much carelessness and misunderstanding in technical writing. In addition, some writers all too frequently refer mainly to review articles which can be especially troublesome if the review is of the interpretative type. The limited outlook of some writers is also deplored in that the scope of the literature referred to is often limited to the author's country. A few glaring examples of factual errors encountered in various radiation protection articles are highlighted; these errors have since been repeated in subsequent review articles. (U.K.)

  17. Mammography: Technique and diagnostic accuracy

    International Nuclear Information System (INIS)

    Kim, Chung Ja; Bahk, Yong Whee; Lee, Don Young

    1974-01-01

    Mammography is now in world wide use, But this has received rather scanty attention in Korea. The purposes of the present communication are twofold: (1) Detailing of technical and photographic aspects of mam in ography and (2) an assessment of its diagnostic accuracy as experienced by us. The clinical materials consisted of 88 cases of mammography performed at the Department of Radiology, St. Mary's Hospital, Catholic Medical College during the 2 years-period from April 1972. We used nonscreen type mammographic or industrial fine- grain films, and a special mammographic device that can be attached to any of the ordinary radiographic machine. Technical factors are shown in Table II. Of 88 cases 19 were operated on or biopsied. There were 7 cases of carcinoma. 8 cases of inflammatory diseases, and 4 cases of benign tumor. Mammographic diagnosis was correct in 85.7% of carcinoma and 87.5% of inflammatory diseases. One misdiagnosis of 7 cases of carcinoma was turned out to be cystosarcoma phylloides. Of 4 cases of benign tumors 2 were correctly diagnosed, and the other 2 mistaken for either inflammatory disease or simple lactating breast. However, none of the benign conditions were diagnosed as malignant process. We found that nonscreen type mammographic or industrial fine-grain films, and hand-processing were necessary in obtaining the mammograms of desirable quality

  18. Accuracy of recumbent height measurement.

    Science.gov (United States)

    Gray, D S; Crider, J B; Kelley, C; Dickinson, L C

    1985-01-01

    Since many patients requiring specialized nutritional support are bedridden, measurement of height for purposes of nutritional assessment or prescription must often be done with the patient in bed. This study examined the accuracy of measuring body height in bed in the supine position. Two measurements were performed on 108 ambulatory inpatients: (1) standing height using a standard height-weight scale, and (2) bed height using a flexible tape. Patients were divided into four groups based on which of two researchers performed each of the two measurements. Each patient was also weighed and self-reported height, weight, sex, and age were recorded. Bed height was significantly longer than standing height by 3.68 cm, but the two measurements were equally precise. It was believed, however, that this 2% difference was probably not clinically significant in most circumstances. Bed height correlated highly with standing height (r = 0.95), and the regression equation was standing height = 13.82 +/- 0.09 bed height. Patients overestimated their heights. Heights recorded by nurses were more accurate when patients were measured than when asked about their heights, but the patients were more often asked than measured.

  19. IGS polar motion measurement accuracy

    Directory of Open Access Journals (Sweden)

    Jim Ray

    2017-11-01

    Full Text Available We elaborate an error budget for the long-term accuracy of IGS (International Global Navigation Satellite System Service polar motion estimates, concluding that it is probably about 25–30 μas (1-sigma overall, although it is not possible to quantify possible contributions (mainly annual that might transfer directly from aliases of subdaily rotational tide errors. The leading sources are biases arising from the need to align daily, observed terrestrial frames, within which the pole coordinates are expressed and which are continuously deforming, to the secular, linear international reference frame. Such biases are largest over spans longer than about a year. Thanks to the very large number of IGS tracking stations, the formal covariance errors are much smaller, around 5 to 10 μas. Large networks also permit the systematic frame-related errors to be more effectively minimized but not eliminated. A number of periodic errors probably also influence polar motion results, mainly at annual, GPS (Global Positioning System draconitic, and fortnightly periods, but their impact on the overall error budget is unlikely to be significant except possibly for annual tidal aliases. Nevertheless, caution should be exercised in interpreting geophysical excitations near any of the suspect periods.

  20. The Accuracy of Cognitive Monitoring during Computer-Based Instruction.

    Science.gov (United States)

    Garhart, Casey; Hannafin, Michael J.

    This study was conducted to determine the accuracy of learners' comprehension monitoring during computer-based instruction and to assess the relationship between enroute monitoring and different levels of learning. Participants were 50 university undergraduate students enrolled in an introductory educational psychology class. All students received…

  1. 30 CFR 74.8 - Measurement, accuracy, and reliability requirements.

    Science.gov (United States)

    2010-07-01

    ... COAL MINE SAFETY AND HEALTH COAL MINE DUST SAMPLING DEVICES Requirements for Continuous Personal Dust... miner whose exposure is being monitored. (b) Accuracy. The ability of a CPDM to determine the true... levels tested, 0.2 to 4.0 mg/m3 for an 8-hour sampling period. (f) Testing conditions. Laboratory and...

  2. Accuracy of road management data collection at various information ...

    African Journals Online (AJOL)

    The most detailed data is required for the operation system whilst the planning system utilises the least detailed data. This paper presents the results of a research project which was carried out in Tanzania in order to establish the loss of data accuracy as the data collection moves from very detailed level (IQLI) to a higher ...

  3. Verification of Positional Accuracy of ZVS3003 Geodetic Control ...

    African Journals Online (AJOL)

    The International GPS Service (IGS) has provided GPS orbit products to the scientific community with increased precision and timeliness. Many users interested in geodetic positioning have adopted the IGS precise orbits to achieve centimeter level accuracy and ensure long-term reference frame stability. Positioning with ...

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

    Science.gov (United States)

    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.

  5. Estimating the accuracy of geographical imputation

    Directory of Open Access Journals (Sweden)

    Boscoe Francis P

    2008-01-01

    Full Text Available Abstract Background To reduce the number of non-geocoded cases researchers and organizations sometimes include cases geocoded to postal code centroids along with cases geocoded with the greater precision of a full street address. Some analysts then use the postal code to assign information to the cases from finer-level geographies such as a census tract. Assignment is commonly completed using either a postal centroid or by a geographical imputation method which assigns a location by using both the demographic characteristics of the case and the population characteristics of the postal delivery area. To date no systematic evaluation of geographical imputation methods ("geo-imputation" has been completed. The objective of this study was to determine the accuracy of census tract assignment using geo-imputation. Methods Using a large dataset of breast, prostate and colorectal cancer cases reported to the New Jersey Cancer Registry, we determined how often cases were assigned to the correct census tract using alternate strategies of demographic based geo-imputation, and using assignments obtained from postal code centroids. Assignment accuracy was measured by comparing the tract assigned with the tract originally identified from the full street address. Results Assigning cases to census tracts using the race/ethnicity population distribution within a postal code resulted in more correctly assigned cases than when using postal code centroids. The addition of age characteristics increased the match rates even further. Match rates were highly dependent on both the geographic distribution of race/ethnicity groups and population density. Conclusion Geo-imputation appears to offer some advantages and no serious drawbacks as compared with the alternative of assigning cases to census tracts based on postal code centroids. For a specific analysis, researchers will still need to consider the potential impact of geocoding quality on their results and evaluate

  6. Evaluation of radiographers’ mammography screen-reading accuracy in Australia

    International Nuclear Information System (INIS)

    Debono, Josephine C; Poulos, Ann E; Houssami, Nehmat; Turner, Robin M; Boyages, John

    2015-01-01

    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

  7. Evaluation of radiographers’ mammography screen-reading accuracy in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Debono, Josephine C, E-mail: josephine.debono@bci.org.au [Westmead Breast Cancer Institute, Westmead, New South Wales (Australia); Poulos, Ann E [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales (Australia); Houssami, Nehmat [Screening and Test Evaluation Program, School of Public Health (A27), Sydney Medical School, University of Sydney, Sydney, New South Wales (Australia); Turner, Robin M [School of Public Health and Community Medicine, University of New South Wales, Sydney, New South Wales (Australia); Boyages, John [Macquarie University Cancer Institute, Macquarie University Hospital, Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales (Australia); Westmead Breast Cancer Institute, Westmead, New South Wales (Australia)

    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.

  8. Accuracies Of Optical Processors For Adaptive Optics

    Science.gov (United States)

    Downie, John D.; Goodman, Joseph W.

    1992-01-01

    Paper presents analysis of accuracies and requirements concerning accuracies of optical linear-algebra processors (OLAP's) in adaptive-optics imaging systems. Much faster than digital electronic processor and eliminate some residual distortion. Question whether errors introduced by analog processing of OLAP overcome advantage of greater speed. Paper addresses issue by presenting estimate of accuracy required in general OLAP that yields smaller average residual aberration of wave front than digital electronic processor computing at given speed.

  9. Value and Accuracy of Multidetector Computed Tomography in Obstructive Jaundice

    International Nuclear Information System (INIS)

    Mathew, Rishi Philip; Moorkath, Abdunnisar; Basti, Ram Shenoy; Suresh, Hadihally B.

    2016-01-01

    Objective; To find out the role of MDCT in the evaluation of obstructive jaundice with respect to the cause and level of the obstruction, and its accuracy. To identify the advantages of MDCT with respect to other imaging modalities. To correlate MDCT findings with histopathology/surgical findings/Endoscopic Retrograde CholangioPancreatography (ERCP) findings as applicable. This was a prospective study conducted over a period of one year from August 2014 to August 2015. Data were collected from 50 patients with clinically suspected obstructive jaundice. CT findings were correlated with histopathology/surgical findings/ERCP findings as applicable. Among the 50 people studied, males and females were equal in number, and the majority belonged to the 41–60 year age group. The major cause for obstructive jaundice was choledocholithiasis. MDCT with reformatting techniques was very accurate in picking a mass as the cause for biliary obstruction and was able to differentiate a benign mass from a malignant one with high accuracy. There was 100% correlation between the CT diagnosis and the final diagnosis regarding the level and type of obstruction. MDCT was able to determine the cause of obstruction with an accuracy of 96%. MDCT with good reformatting techniques has excellent accuracy in the evaluation of obstructive jaundice with regards to the level and cause of obstruction

  10. High accuracy wavelength calibration for a scanning visible spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, Filippo; Bell, Ronald E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2010-10-15

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies {<=}0.2 A. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of {approx}0.25 A has been demonstrated. With the addition of a high resolution (0.075 arc sec) optical encoder on the grating stage, greater precision ({approx}0.005 A) is possible, allowing absolute velocity measurements within {approx}0.3 km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.

  11. Accuracy of 11-year-olds selfreported school lunch consumption

    DEFF Research Database (Denmark)

    Lyng, Nina

    accuracy differ by the lunch format consumed (Paper III) Material and methods The study was conducted as a cross-sectional dietary reporting study. The population consisted of 11-year-old children from three public schools in Copenhagen. The study was conducted on two consecutive days and assessed...... in general. Objectives The aim of the present thesis was to assess food level reporting accuracy in Danish 11-year-old children’s self-reported school lunch consumption, and the aim was operationalized in following objectives. 1- To identify food items clustering by lunch format (Preliminary analyses) 2......- To assess reporting accuracy in relation to gender and self-reported methods (Paper I) 3- To address aspects of reporting inaccuracy from intrusions by food group, against different objective measures, and classification of intrusions in stretches and confabulations (Paper II) 4- To assess how reporting...

  12. Digital versus conventional implant impressions for edentulous patients: accuracy outcomes.

    Science.gov (United States)

    Papaspyridakos, Panos; Gallucci, German O; Chen, Chun-Jung; Hanssen, Stijn; Naert, Ignace; Vandenberghe, Bart

    2016-04-01

    To compare the accuracy of digital and conventional impression techniques for completely edentulous patients and to determine the effect of different variables on the accuracy outcomes. A stone cast of an edentulous mandible with five implants was fabricated to serve as master cast (control) for both implant- and abutment-level impressions. Digital impressions (n = 10) were taken with an intraoral optical scanner (TRIOS, 3shape, Denmark) after connecting polymer scan bodies. For the conventional polyether impressions of the master cast, a splinted and a non-splinted technique were used for implant-level and abutment-level impressions (4 cast groups, n = 10 each). Master casts and conventional impression casts were digitized with an extraoral high-resolution scanner (IScan D103i, Imetric, Courgenay, Switzerland) to obtain digital volumes. Standard tessellation language (STL) datasets from the five groups of digital and conventional impressions were superimposed with the STL dataset from the master cast to assess the 3D (global) deviations. To compare the master cast with digital and conventional impressions at the implant level, analysis of variance (ANOVA) and Scheffe's post hoc test was used, while Wilcoxon's rank-sum test was used for testing the difference between abutment-level conventional impressions. Significant 3D deviations (P impressions (P > 0.001). Digital implant impressions are as accurate as conventional implant impressions. The splinted, implant-level impression technique is more accurate than the non-splinted one for completely edentulous patients, whereas there was no difference in the accuracy at the abutment level. The implant angulation up to 15° did not affect the accuracy of implant impressions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. [Navigation in implantology: Accuracy assessment regarding the literature].

    Science.gov (United States)

    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 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.

  14. Do Shared Interests Affect the Accuracy of Budgets?

    Directory of Open Access Journals (Sweden)

    Ilse Maria Beuren

    2015-04-01

    Full Text Available The creation of budgetary slack is a phenomenon associated with various behavioral aspects. This study focuses on accuracy in budgeting when the benefit of the slack is shared between the unit manager and his/her assistant. In this study, accuracy is measured by the level of slack in the budget, and the benefit of slack represents a financial consideration for the manager and the assistant. The study aims to test how shared interests in budgetary slack affect the accuracy of budget reports in an organization. To this end, an experimental study was conducted with a sample of 90 employees in management and other leadership positions at a cooperative that has a variable compensation plan based on the achievement of organizational goals. The experiment conducted in this study is consubstantiated by the study of Church, Hannan and Kuang (2012, which was conducted with a sample of undergraduate students in the United States and used a quantitative approach to analyze the results. In the first part of the experiment, the results show that when budgetary slack is not shared, managers tend to create greater slack when the assistant is not aware of the creation of slack; these managers thus generate a lower accuracy index than managers whose assistants are aware of the creation of slack. When budgetary slack is shared, there is higher average slack when the assistant is aware of the creation of slack. In the second part of the experiment, the accuracy index is higher for managers who prepare the budget with the knowledge that their assistants prefer larger slack values. However, the accuracy level differs between managers who know that their assistants prefer maximizing slack values and managers who do not know their assistants' preference regarding slack. These results contribute to the literature by presenting evidence of managers' behavior in the creation of budgetary slack in scenarios in which they share the benefits of slack with their assistants.

  15. Quality of reporting of diagnostic accuracy studies

    NARCIS (Netherlands)

    Smidt, N.; Rutjes, A.W.; Windt - Mens, van der D.A.W.M.; Ostelo, R.W.J.G.; Reitsma, J.B.; Bouter, L.M.; Vet, de H.C.W.

    2005-01-01

    PURPOSE: To evaluate quality of reporting in diagnostic accuracy articles published in 2000 in journals with impact factor of at least 4 by using items of Standards for Reporting of Diagnostic Accuracy (STARD) statement published later in 2003. MATERIALS AND METHODS: English-language articles on

  16. Accuracy of Parent Identification of Stuttering Occurrence

    Science.gov (United States)

    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…

  17. Improving Accuracy of Processing Through Active Control

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available An important task of modern mathematical statistics with its methods based on the theory of probability is a scientific estimate of measurement results. There are certain costs under control, and under ineffective control when a customer has got defective products these costs are significantly higher because of parts recall.When machining the parts, under the influence of errors a range scatter of part dimensions is offset towards the tolerance limit. To improve a processing accuracy and avoid defective products involves reducing components of error in machining, i.e. to improve the accuracy of machine and tool, tool life, rigidity of the system, accuracy of the adjustment. In a given time it is also necessary to adapt machine.To improve an accuracy and a machining rate there, currently  become extensively popular various the in-process gaging devices and controlled machining that uses adaptive control systems for the process monitoring. Improving the accuracy in this case is compensation of a majority of technological errors. The in-cycle measuring sensors (sensors of active control allow processing accuracy improvement by one or two quality and provide a capability for simultaneous operation of several machines.Efficient use of in-cycle measuring sensors requires development of methods to control the accuracy through providing the appropriate adjustments. Methods based on the moving average, appear to be the most promising for accuracy control since they include data on the change in some last measured values of the parameter under control.

  18. Serum albumin: accuracy and clinical use.

    Science.gov (United States)

    Infusino, Ilenia; Panteghini, Mauro

    2013-04-18

    Albumin is the major plasma protein and its determination is used for the prognostic assessment of several diseases. Clinical guidelines call for monitoring of serum albumin with specific target cut-offs that are independent of the assay used. This requires accurate and equivalent results among different commercially available methods (i.e., result standardization) through a consistent definition and application of a reference measurement system. This should be associated with the definition of measurement uncertainty goals based on medical relevance of serum albumin to make results reliable for patient management. In this paper, we show that, in the current situation, if one applies analytical goals for serum albumin measurement derived from its biologic variation, the uncertainty budget derived from each step of the albumin traceability chain is probably too high to fulfil established quality levels for albumin measurement and to guarantee the accuracy needed for clinical usefulness of the test. The situation is further worsened if non-specific colorimetric methods are used for albumin measurement as they represent an additional random source of uncertainty. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. The Influence of Motor Skills on Measurement Accuracy

    Science.gov (United States)

    Brychta, Petr; Sadílek, Marek; Brychta, Josef

    2016-10-01

    This innovative study trying to do interdisciplinary interface at first view different ways fields: kinantropology and mechanical engineering. A motor skill is described as an action which involves the movement of muscles in a body. Gross motor skills permit functions as a running, jumping, walking, punching, lifting and throwing a ball, maintaining a body balance, coordinating etc. Fine motor skills captures smaller neuromuscular actions, such as holding an object between the thumb and a finger. In mechanical inspection, the accuracy of measurement is most important aspect. The accuracy of measurement to some extent is also dependent upon the sense of sight or sense of touch associated with fine motor skills. It is therefore clear that the level of motor skills will affect the precision and accuracy of measurement in metrology. Aim of this study is literature review to find out fine motor skills level of individuals and determine the potential effect of different fine motor skill performance on precision and accuracy of mechanical engineering measuring.

  20. An Analysis of the Influence of Fundamental Values' Estimation Accuracy on Financial Markets

    OpenAIRE

    Takahashi, Hiroshi

    2010-01-01

    This research analyzed the influence of the differences in the forecast accuracy of fundamental values on the financial market. As a result of intensive experiments in the market, we made the following interesting findings: (1) improvements in forecast accuracy of fundamentalists can contribute to an increase in the number of fundamentalists; (2) certain situations might occur, according to the level of forecast accuracy of fundamentalists, in which fundamentalists and passive management coex...

  1. Enhancement of diffusers BRDF accuracy

    Science.gov (United States)

    Otter, Gerard; Bazalgette Courrèges-Lacoste, Gregory; van Brug, Hedser; Schaarsberg, Jos Groote; Delwart, Steven; del Bello, Umberto

    2017-11-01

    This paper reports the result of an ESA study conducted at TNO to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibration. Knowledge of the behaviour of the diffuser is therefore most important. From measurements of launched instruments in-orbit it has been discovered that when a diffuser is used in the vacuum of space the BRDF can change with respect to the one in ambient conditions. This is called the air/vacuum effect and has been simulated in this study by measuring the BRDF in a laboratory in ambient as well as vacuum conditions. Another studied effect is related to the design parameters of the optical system and the scattering properties of the diffuser. The effect is called Spectral Features and is a noise like structure superimposed on the diffuser BRDF. Modern space spectrometers, which have high spectral resolution and/or a small field of view (high spatial resolution) are suffering from this effect. The choice of diffuser can be very critical with respect to the required absolute radiometric calibration of an instrument. Even if the Spectral Features are small it can influence the error budget of the retrieval algorithms for the level 2 products. in this presentation diffuser trade-off results are presented and the Spectral Features model applied to the optical configuration of the MERIS instrument is compared to in-flight measurements of MERIS.

  2. Prognostic accuracy of antenatal neonatology consultation.

    Science.gov (United States)

    Kukora, S; Gollehon, N; Weiner, G; Laventhal, N

    2017-01-01

    Neonatologists provide antenatal counseling to support shared decision-making for complicated pregnancies. Poor or ambiguous prognostication can lead to inappropriate treatment and parental distress. We sought to evaluate the accuracy of antenatal prognosticaltion. A retrospective cohort was assembled from a prospectively populated database of all outpatient neonatology consultations. On the basis of the written consultation, fetuses were characterized by diagnosis groups (multiple anomalies or genetic disorders, single major anomaly and obstetric complications), assigned to five prognostic categories (I=survivable, IIA=uncertain but likely survivable, II=uncertain, IIB=uncertain but likely non-survivable, III non-survivable) and two final outcome categories (fetal demise/in-hospital neonatal death or survival to hospital discharge). When possible, status at last follow-up was recorded for those discharged from the hospital. Prognostic accuracy was assessed using unweighted, multi-level likelihood ratios (LRs). The final cohort included 143 fetuses/infants distributed nearly evenly among the three diagnosis groups. Over half (64%) were assigned an uncertain prognosis, but most of these could be divided into 'likely survivable' or 'likely non-survivable' subgroups. Overall survival for the entire cohort was 62% (89/143). All but one of the fetuses assigned a non-survivable prognosis suffered fetal demise or died before hospital discharge. The neonatologist's antenatal prognosis accurately predicted the probability of survival by prognosis group (LR I=4.56, LR IIA=10.53, LR II=4.71, LR IIB=0.099, LR III=0.040). The LRs clearly differentiated between fetuses with high and low probability of survival. Eleven fetuses (7.7%) had misalignment between the predicted prognosis and outcome. Five died before discharge despite being given category I or IIA prognoses, whereas six infants with category IIB or III prognoses survived to discharge, though some of these were

  3. Accuracy Limitations in Optical Linear Algebra Processors

    Science.gov (United States)

    Batsell, Stephen Gordon

    1990-01-01

    One of the limiting factors in applying optical linear algebra processors (OLAPs) to real-world problems has been the poor achievable accuracy of these processors. Little previous research has been done on determining noise sources from a systems perspective which would include noise generated in the multiplication and addition operations, noise from spatial variations across arrays, and from crosstalk. In this dissertation, we propose a second-order statistical model for an OLAP which incorporates all these system noise sources. We now apply this knowledge to determining upper and lower bounds on the achievable accuracy. This is accomplished by first translating the standard definition of accuracy used in electronic digital processors to analog optical processors. We then employ our second-order statistical model. Having determined a general accuracy equation, we consider limiting cases such as for ideal and noisy components. From the ideal case, we find the fundamental limitations on improving analog processor accuracy. From the noisy case, we determine the practical limitations based on both device and system noise sources. These bounds allow system trade-offs to be made both in the choice of architecture and in individual components in such a way as to maximize the accuracy of the processor. Finally, by determining the fundamental limitations, we show the system engineer when the accuracy desired can be achieved from hardware or architecture improvements and when it must come from signal pre-processing and/or post-processing techniques.

  4. Multiple sequence alignment accuracy and phylogenetic inference.

    Science.gov (United States)

    Ogden, T Heath; Rosenberg, Michael S

    2006-04-01

    Phylogenies are often thought to be more dependent upon the specifics of the sequence alignment rather than on the method of reconstruction. Simulation of sequences containing insertion and deletion events was performed in order to determine the role that alignment accuracy plays during phylogenetic inference. Data sets were simulated for pectinate, balanced, and random tree shapes under different conditions (ultrametric equal branch length, ultrametric random branch length, nonultrametric random branch length). Comparisons between hypothesized alignments and true alignments enabled determination of two measures of alignment accuracy, that of the total data set and that of individual branches. In general, our results indicate that as alignment error increases, topological accuracy decreases. This trend was much more pronounced for data sets derived from more pectinate topologies. In contrast, for balanced, ultrametric, equal branch length tree shapes, alignment inaccuracy had little average effect on tree reconstruction. These conclusions are based on average trends of many analyses under different conditions, and any one specific analysis, independent of the alignment accuracy, may recover very accurate or inaccurate topologies. Maximum likelihood and Bayesian, in general, outperformed neighbor joining and maximum parsimony in terms of tree reconstruction accuracy. Results also indicated that as the length of the branch and of the neighboring branches increase, alignment accuracy decreases, and the length of the neighboring branches is the major factor in topological accuracy. Thus, multiple-sequence alignment can be an important factor in downstream effects on topological reconstruction.

  5. Accuracy and precision in thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Marshall, T.O.

    1984-01-01

    The question of accuracy and precision in thermoluminescent dosimetry, particularly in relation to lithium fluoride phosphor, is discussed. The more important sources of error, including those due to the detectors, the reader, annealing and dosemeter design, are identified and methods of reducing their effects on accuracy and precision to a minimum are given. Finally, the accuracy and precision achievable for three quite different applications are discussed, namely, for personal dosimetry, environmental monitoring and for the measurement of photon dose distributions in phantoms. (U.K.)

  6. High Accuracy Nonlinear Control and Estimation for Machine Tool Systems

    DEFF Research Database (Denmark)

    Papageorgiou, Dimitrios

    Component mass production has been the backbone of industry since the second industrial revolution, and machine tools are producing parts of widely varying size and design complexity. The ever-increasing level of automation in modern manufacturing processes necessitates the use of more...... sophisticated machine tool systems that are adaptable to different workspace conditions, while at the same time being able to maintain very narrow workpiece tolerances. The main topic of this thesis is to suggest control methods that can maintain required manufacturing tolerances, despite moderate wear and tear....... The purpose is to ensure that full accuracy is maintained between service intervals and to advice when overhaul is needed. The thesis argues that quality of manufactured components is directly related to the positioning accuracy of the machine tool axes, and it shows which low level control architectures...

  7. Print to Braille: Preparation and Accuracy of Mathematics Materials in K-12 Education

    Science.gov (United States)

    Herzberg, Tina S.; Rosenblum, L. Penny

    2014-01-01

    Introduction: This study analyzed the accuracy of 107 mathematics worksheets prepared for tactile learners. The mean number of errors was calculated, and we examined whether there was a significant difference in the level of accuracy based on National Library Service for the Blind and Physically Handicapped (NLS) certification or job role of…

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

    Science.gov (United States)

    Krause, Jean C.; Tessler, Morgan P.

    2016-01-01

    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.…

  9. An assessment of the accuracy of contrast enema for the diagnosis ...

    African Journals Online (AJOL)

    Diagnostic accuracy levels were calculated by comparing radiological results with histology results, which is the gold standard. Results: Diagnostic accuracy of contrast enema was 78%, sensitivity was 94.4% and the negative predictive value was 95.7%. Specificity (68.8%) and positive predictive values (63%) were ...

  10. Accuracy comparison of Pléiades satellite ortho-images using GPS ...

    African Journals Online (AJOL)

    Ivan Henrico

    imagery to achieve a certain level of geometric accuracy are in literature well .... The Pléiades primary product can be described as the processing ..... This article studied the influence of two types of GCP collection methods on the accuracy of.

  11. Matter power spectrum and the challenge of percent accuracy

    OpenAIRE

    Schneider, Aurel; Teyssier, Romain; Potter, Doug; Stadel, Joachim; Onions, Julian; Reed, Darren S.; Smith, Robert E.; Springel, Volker; Pearce, Frazer R.; Scoccimarro, Roman

    2015-01-01

    Future galaxy surveys require one percent precision in the theoretical knowledge of the power spectrum over a large range including very nonlinear scales. While this level of accuracy is easily obtained in the linear regime with perturbation theory, it represents a serious challenge for small scales where numerical simulations are required. In this paper we quantify the precision of present-day $N$-body methods, identifying main potential error sources from the set-up of initial conditions to...

  12. Speed-Accuracy Tradeoff in Olfaction

    National Research Council Canada - National Science Library

    Rinberg, Dmitry; Koulakov, ALexel; Gelperin, Alan

    2006-01-01

    The basic psychophysical principle of speed-accuracy tradeoff (SAT) has been used to understand key aspects of neuronal information processing in vision and audition, but the principle of SAT is still debated in olfaction...

  13. A Note on "Accuracy" and "Precision"

    Science.gov (United States)

    Stallings, William M.; Gillmore, Gerald M.

    1971-01-01

    Advocates the use of precision" rather than accuracy" in defining reliability. These terms are consistently differentiated in certain sciences. Review of psychological and measurement literature reveals, however, interchangeable usage of the terms in defining reliability. (Author/GS)

  14. Predictive accuracy of backpropagation neural network ...

    Indian Academy of Sciences (India)

    incorporated into the BP model for high accuracy management purpose of irrigation water, which relies on accurate values of ET ... as seen from the recent food crisis demonstra- tion in most .... layers by using Geographical Information System.

  15. Strategies to Increase Accuracy in Text Classification

    NARCIS (Netherlands)

    D. Blommesteijn (Dennis)

    2014-01-01

    htmlabstractText classification via supervised learning involves various steps from processing raw data, features extraction to training and validating classifiers. Within these steps implementation decisions are critical to the resulting classifier accuracy. This paper contains a report of the

  16. Evidence for a confidence-accuracy relationship in memory for same- and cross-race faces.

    Science.gov (United States)

    Nguyen, Thao B; Pezdek, Kathy; Wixted, John T

    2017-12-01

    Discrimination accuracy is usually higher for same- than for cross-race faces, a phenomenon known as the cross-race effect (CRE). According to prior research, the CRE occurs because memories for same- and cross-race faces rely on qualitatively different processes. However, according to a continuous dual-process model of recognition memory, memories that rely on qualitatively different processes do not differ in recognition accuracy when confidence is equated. Thus, although there are differences in overall same- and cross-race discrimination accuracy, confidence-specific accuracy (i.e., recognition accuracy at a particular level of confidence) may not differ. We analysed datasets from four recognition memory studies on same- and cross-race faces to test this hypothesis. Confidence ratings reliably predicted recognition accuracy when performance was above chance levels (Experiments 1, 2, and 3) but not when performance was at chance levels (Experiment 4). Furthermore, at each level of confidence, confidence-specific accuracy for same- and cross-race faces did not significantly differ when overall performance was above chance levels (Experiments 1, 2, and 3) but significantly differed when overall performance was at chance levels (Experiment 4). Thus, under certain conditions, high-confidence same-race and cross-race identifications may be equally reliable.

  17. Accuracy Assessment of Different Digital Surface Models

    Directory of Open Access Journals (Sweden)

    Ugur Alganci

    2018-03-01

    Full Text Available Digital elevation models (DEMs, which can occur in the form of digital surface models (DSMs or digital terrain models (DTMs, are widely used as important geospatial information sources for various remote sensing applications, including the precise orthorectification of high-resolution satellite images, 3D spatial analyses, multi-criteria decision support systems, and deformation monitoring. The accuracy of DEMs has direct impacts on specific calculations and process chains; therefore, it is important to select the most appropriate DEM by considering the aim, accuracy requirement, and scale of each study. In this research, DSMs obtained from a variety of satellite sensors were compared to analyze their accuracy and performance. For this purpose, freely available Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER 30 m, Shuttle Radar Topography Mission (SRTM 30 m, and Advanced Land Observing Satellite (ALOS 30 m resolution DSM data were obtained. Additionally, 3 m and 1 m resolution DSMs were produced from tri-stereo images from the SPOT 6 and Pleiades high-resolution (PHR 1A satellites, respectively. Elevation reference data provided by the General Command of Mapping, the national mapping agency of Turkey—produced from 30 cm spatial resolution stereo aerial photos, with a 5 m grid spacing and ±3 m or better overall vertical accuracy at the 90% confidence interval (CI—were used to perform accuracy assessments. Gross errors and water surfaces were removed from the reference DSM. The relative accuracies of the different DSMs were tested using a different number of checkpoints determined by different methods. In the first method, 25 checkpoints were selected from bare lands to evaluate the accuracies of the DSMs on terrain surfaces. In the second method, 1000 randomly selected checkpoints were used to evaluate the methods’ accuracies for the whole study area. In addition to the control point approach, vertical cross

  18. Increasing of AC compensation method accuracy

    International Nuclear Information System (INIS)

    Havlicek, V.; Pokorny, M.

    2003-01-01

    The original MMF compensation method allows the magnetic properties of single sheets and strips to be measured in the same way as the closed specimen properties. The accuracy of the method is limited due to the finite gain of the feedback loop fulfilling the condition of its stability. Digitalisation of the compensation loop appropriate processing of the error signal can rapidly improve the accuracy. The basic ideas of this new approach and the experimental results are described in this paper

  19. Increasing of AC compensation method accuracy

    Science.gov (United States)

    Havlíček, V.; Pokorný, M.

    2003-01-01

    The original MMF compensation method allows the magnetic properties of single sheets and strips to be measured in the same way as the closed specimen properties. The accuracy of the method is limited due to the finite gain of the feedback loop fulfilling the condition of its stability. Digitalisation of the compensation loop appropriate processing of the error signal can rapidly improve the accuracy. The basic ideas of this new approach and the experimental results are described in this paper.

  20. ACCURACY OF MEASUREMENTS IN OBLIQUE AERIAL IMAGES FOR URBAN ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    W. Ostrowski

    2016-10-01

    Full Text Available Oblique aerial images have been a source of data for urban areas for several years. However, the accuracy of measurements in oblique images during this time has been limited to a single meter due to the use of direct -georeferencing technology and the underlying digital elevation model. Therefore, oblique images have been used mostly for visualization purposes. This situation changed in recent years as new methods, which allowed for a higher accuracy of exterior orientation, were developed. Current developments include the process of determining exterior orientation and the previous but still crucial process of tie point extraction. Progress in this area was shown in the ISPRS/EUROSDR Benchmark on Multi-Platform Photogrammetry and is also noticeable in the growing interest in the use of this kind of imagery. The higher level of accuracy in the orientation of oblique aerial images that has become possible in the last few years should result in a higher level of accuracy in the measurements of these types of images. The main goal of this research was to set and empirically verify the accuracy of measurements in oblique aerial images. The research focused on photogrammetric measurements composed of many images, which use a high overlap within an oblique dataset and different view angles. During the experiments, two series of images of urban areas were used. Both were captured using five DigiCam cameras in a Maltese cross configuration. The tilt angles of the oblique cameras were 45 degrees, and the position of the cameras during flight used a high grade GPS/INS navigation system. The orientation of the images was set using the Pix4D Mapper Pro software with both measurements of the in-flight camera position and the ground control points (measured with GPS RTK technology. To control the accuracy, check points were used (which were also measured with GPS RTK technology. As reference data for the whole study, an area of the city-based map was used

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

    Science.gov (United States)

    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.

  2. Visual Inspection Displays Good Accuracy for Detecting Caries Lesions

    DEFF Research Database (Denmark)

    Twetman, Svante

    2015-01-01

    /QUESTION: To evaluate the overall accuracy of visual methods for detecting caries lesions. SOURCE OF FUNDING: Brazilian government (Process 2012/17888-1). TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data LEVEL OF EVIDENCE: Level 1: Good-quality, patient-oriented evidence STRENGTH OF RECOMMENDATION......ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Visual inspection for caries detection: a systematic review and meta-analysis. Gimenez T, Piovesan C, Braga MM, Raggio DP, Deery C, Ricketts DN, Ekstrand DR, Mendes FM. J Dent Res 2015;94(7):895-904. REVIEWER: Svante Twetman, DDS, PhD, Odont Dr PURPOSE...

  3. Accuracy of Replicating Static Torque and its Effect on Shooting Accuracy in Young Basketball Players

    Directory of Open Access Journals (Sweden)

    Struzik Artur

    2014-12-01

    Full Text Available Purpose. Accurate shooting in basketball is a prerequisite for success. Coordination ability, one of the abilities that determine the repeatability of accurate shooting, is based on kinesthetic differentiation. The aim of the study was to evaluate the strength component of kinesthetic differentiation ability and determine its relationship with shooting accuracy. Methods. Peak muscle torque of the elbow extensors under static conditions was measured in 12 young basketball players. Participants then reproduced the same movement at a perceived magnitude of 25%, 50%, and 75% of static peak torque, with error scores calculated as a measure of kinesthetic differentiation. The results were compared with players’ field goal percentages calculated during game play in a regional championship. Results. No statistically significant relationships were found between the level of kinesthetic differentiation ability and field goal percentage. Additionally, no upper limb asymmetry was found in the sample. Conclusions. The relatively high levels of elbow static peak torque suggest the importance of upper limb strength in contemporary basketball. The lack of a statistically significant difference between the right and left limbs decreases the risk of suffering injury. It is likely that choosing other suitable tests would demonstrate the relationships between field goal percentage and kinesthetic differentiation ability.

  4. Accuracy Assessment and Analysis for GPT2

    Directory of Open Access Journals (Sweden)

    YAO Yibin

    2015-07-01

    Full Text Available GPT(global pressure and temperature is a global empirical model usually used to provide temperature and pressure for the determination of tropospheric delay, there are some weakness to GPT, these have been improved with a new empirical model named GPT2, which not only improves the accuracy of temperature and pressure, but also provides specific humidity, water vapor pressure, mapping function coefficients and other tropospheric parameters, and no accuracy analysis of GPT2 has been made until now. In this paper high-precision meteorological data from ECWMF and NOAA were used to test and analyze the accuracy of temperature, pressure and water vapor pressure expressed by GPT2, testing results show that the mean Bias of temperature is -0.59℃, average RMS is 3.82℃; absolute value of average Bias of pressure and water vapor pressure are less than 1 mb, GPT2 pressure has average RMS of 7 mb, and water vapor pressure no more than 3 mb, accuracy is different in different latitudes, all of them have obvious seasonality. In conclusion, GPT2 model has high accuracy and stability on global scale.

  5. Reliability and accuracy of Crystaleye spectrophotometric system.

    Science.gov (United States)

    Chen, Li; Tan, Jian Guo; Zhou, Jian Feng; Yang, Xu; Du, Yang; Wang, Fang Ping

    2010-01-01

    to develop an in vitro shade-measuring model to evaluate the reliability and accuracy of the Crystaleye spectrophotometric system, a newly developed spectrophotometer. four shade guides, VITA Classical, VITA 3D-Master, Chromascop and Vintage Halo NCC, were measured with the Crystaleye spectrophotometer in a standardised model, ten times for 107 shade tabs. The shade-matching results and the CIE L*a*b* values of the cervical, body and incisal regions for each measurement were automatically analysed using the supporting software. Reliability and accuracy were calculated for each shade tab both in percentage and in colour difference (ΔE). Difference was analysed by one-way ANOVA in the cervical, body and incisal regions. range of reliability was 88.81% to 98.97% and 0.13 to 0.24 ΔE units, and that of accuracy was 44.05% to 91.25% and 1.03 to 1.89 ΔE units. Significant differences in reliability and accuracy were found between the body region and the cervical and incisal regions. Comparisons made among regions and shade guides revealed that evaluation in ΔE was prone to disclose the differences. measurements with the Crystaleye spectrophotometer had similar, high reliability in different shade guides and regions, indicating predictable repeated measurements. Accuracy in the body region was high and less variable compared with the cervical and incisal regions.

  6. Coordinate metrology accuracy of systems and measurements

    CERN Document Server

    Sładek, Jerzy A

    2016-01-01

    This book focuses on effective methods for assessing the accuracy of both coordinate measuring systems and coordinate measurements. It mainly reports on original research work conducted by Sladek’s team at Cracow University of Technology’s Laboratory of Coordinate Metrology. The book describes the implementation of different methods, including artificial neural networks, the Matrix Method, the Monte Carlo method and the virtual CMM (Coordinate Measuring Machine), and demonstrates how these methods can be effectively used in practice to gauge the accuracy of coordinate measurements. Moreover, the book includes an introduction to the theory of measurement uncertainty and to key techniques for assessing measurement accuracy. All methods and tools are presented in detail, using suitable mathematical formulations and illustrated with numerous examples. The book fills an important gap in the literature, providing readers with an advanced text on a topic that has been rapidly developing in recent years. The book...

  7. Evaluating measurement accuracy a practical approach

    CERN Document Server

    Rabinovich, Semyon G

    2017-01-01

    This book presents a systematic and comprehensive exposition of the theory of measurement accuracy and provides solutions that fill significant and long-standing gaps in the classical theory. It eliminates the shortcomings of the classical theory by including methods for estimating accuracy of single measurements, the most common type of measurement. The book also develops methods of reduction and enumeration for indirect measurements, which do not require Taylor series and produce a precise solution to this problem. It produces grounded methods and recommendations for summation of errors. The monograph also analyzes and critiques two foundation metrological documents, the International Vocabulary of Metrology (VIM) and the Guide to the Expression of Uncertainty in Measurement (GUM), and discusses directions for their revision. This new edition adds a step-by-step guide on how to evaluate measurement accuracy and recommendations on how to calculate systematic error of multiple measurements. There is also an e...

  8. Social class, contextualism, and empathic accuracy.

    Science.gov (United States)

    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.

  9. Ex-post evaluations of demand forecast accuracy

    DEFF Research Database (Denmark)

    Nicolaisen, Morten Skou; Driscoll, Patrick Arthur

    2014-01-01

    Travel demand forecasts play a crucial role in the preparation of decision support to policy makers in the field of transport planning. The results feed directly into impact appraisals such as cost benefit analyses and environmental impact assessments, which are mandatory for large public works...... projects in many countries. Over the last couple of decades there has been an increasing attention to the lack of demand forecast accuracy, but since data availability for comprehensive ex- post appraisals is problematic, such studies are still relatively rare. The present paper presents a review...... of the largest ex-post studies of demand forecast accuracy for transport infrastructure projects. The focus is twofold; to provide an overview of observed levels of demand forecast inaccuracy and to explore the primary explanations offered for the observed inaccuracy. Inaccuracy in the form of both bias...

  10. Systematic reviews of diagnostic test accuracy

    DEFF Research Database (Denmark)

    Leeflang, Mariska M G; Deeks, Jonathan J; Gatsonis, Constantine

    2008-01-01

    More and more systematic reviews of diagnostic test accuracy studies are being published, but they can be methodologically challenging. In this paper, the authors present some of the recent developments in the methodology for conducting systematic reviews of diagnostic test accuracy studies....... Restrictive electronic search filters are discouraged, as is the use of summary quality scores. Methods for meta-analysis should take into account the paired nature of the estimates and their dependence on threshold. Authors of these reviews are advised to use the hierarchical summary receiver...

  11. Electron ray tracing with high accuracy

    International Nuclear Information System (INIS)

    Saito, K.; Okubo, T.; Takamoto, K.; Uno, Y.; Kondo, M.

    1986-01-01

    An electron ray tracing program is developed to investigate the overall geometrical and chromatic aberrations in electron optical systems. The program also computes aberrations due to manufacturing errors in lenses and deflectors. Computation accuracy is improved by (1) calculating electrostatic and magnetic scalar potentials using the finite element method with third-order isoparametric elements, and (2) solving the modified ray equation which the aberrations satisfy. Computation accuracy of 4 nm is achieved for calculating optical properties of the system with an electrostatic lens

  12. Revolutionizing radiographic diagnostic accuracy in periodontics

    Directory of Open Access Journals (Sweden)

    Brijesh Sharma

    2016-01-01

    Full Text Available Effective diagnostic accuracy has in some way been the missing link between periodontal diagnosis and treatment. Most of the clinicians rely on the conventional two-dimensional (2D radiographs. But being a 2D image, it has its own limitations. 2D images at times can give an incomplete picture about the severity or type of disease and can further affect the treatment plan. Cone beam computed tomography (CBCT has a better potential for detecting periodontal bone defects with accuracy. The purpose here is to describe how CBCT imaging is beneficial in accurate diagnosis and will lead to a precise treatment plan.

  13. ACCURACY ANALYSIS OF KINECT DEPTH DATA

    Directory of Open Access Journals (Sweden)

    K. Khoshelham

    2012-09-01

    Full Text Available This paper presents an investigation of the geometric quality of depth data obtained by the Kinect sensor. Based on the mathematical model of depth measurement by the sensor 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 millimetres up to about 4 cm at the maximum range of the sensor. The accuracy of the data is also found to be influenced by the low resolution of the depth measurements.

  14. Final Technical Report: Increasing Prediction Accuracy.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hansen, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stein, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    PV performance models are used to quantify the value of PV plants in a given location. They combine the performance characteristics of the system, the measured or predicted irradiance and weather at a site, and the system configuration and design into a prediction of the amount of energy that will be produced by a PV system. These predictions must be as accurate as possible in order for finance charges to be minimized. Higher accuracy equals lower project risk. The Increasing Prediction Accuracy project at Sandia focuses on quantifying and reducing uncertainties in PV system performance models.

  15. Accuracy Of Stereometry In Assessing Orthognathic Surgery

    Science.gov (United States)

    King, Geoffrey E.; Bays, R. A.

    1983-07-01

    An X-ray stereometric technique has been developed for the determination of 3-dimensional coordinates of spherical metallic markers previously implanted in monkey skulls. The accuracy of the technique is better than 0.5mm. and uses readily available demountable X-ray equipment. The technique is used to study the effects and stability of experimental orthognathic surgery.

  16. Accuracy of sampling during mushroom cultivation

    NARCIS (Netherlands)

    Baars, J.J.P.; Hendrickx, P.M.; Sonnenberg, A.S.M.

    2015-01-01

    Experiments described in this report were performed to increase the accuracy of the analysis of the biological efficiency of Agaricus bisporus strains. Biological efficiency is a measure of the efficiency with which the mushroom strains use dry matter in the compost to produce mushrooms (expressed

  17. Laser measuring scanners and their accuracy limits

    Science.gov (United States)

    Jablonski, Ryszard

    1993-09-01

    Scanning methods have gained the greater importance for some years now due to a short measuring time and wide range of application in flexible manufacturing processes. This paper is a summing up of the autho?s creative scientific work in the field of measuring scanners. The research conducted allowed to elaborate the optimal configurations of measuring systems based on the scanning method. An important part of the work was the analysis of a measuring scanner - as a transducer of an angle rotation into the linear displacement which resulted in obtaining its much higher accuracy and finally in working out a measuring scanner eliminating the use of an additional reference standard. The completion of the work is an attempt to determine an attainable accuracy limit of scanning measurement of both length and angle. Using a high stability deflector and a corrected scanning lens one can obtain the angle determination over 30 (or 2 mm) to an accuracy 0 (or 0 tm) when the measuring rate is 1000 Hz or the range d60 (4 mm) with accuracy 0 " (0 jim) and measurement frequency 6 Hz.

  18. High Accuracy Transistor Compact Model Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Hembree, Charles E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Mar, Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.

  19. Accuracy of References in Five Entomology Journals.

    Science.gov (United States)

    Kristof, Cynthia

    ln this paper, the bibliographical references in five core entomology journals are examined for citation accuracy in order to determine if the error rates are similar. Every reference printed in each journal's first issue of 1992 was examined, and these were compared to the original (cited) publications, if possible, in order to determine the…

  20. Accuracy of abdominal auscultation for bowel obstruction

    DEFF Research Database (Denmark)

    Breum, Birger Michael; Rud, Bo; Kirkegaard, Thomas

    2015-01-01

    AIM: To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction. METHODS: Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann(®) Electronic Stethoscope. The recordings were process...

  1. Positional Accuracy Assessment for Effective Shoreline Change ...

    African Journals Online (AJOL)

    Ghana Mining Journal ... Data quality may be expressed in terms of several indicators such as attributes, temporal or positional accuracies. ... It is concluded that for the purpose of shoreline change analysis, such as shoreline change trends, large scale data sources should be used where possible for accurate ...

  2. Accuracy assessment of an industrial actuator

    DEFF Research Database (Denmark)

    Dalla Costa, Giuseppe; Genta, Gianfranco; Barbato, Giulio

    2016-01-01

    A commercial linear actuator equipped with a 0.1 μm resolution encoder was used as a contact displacement sensor with adjustable force. The accuracy of the position reading of the actuator was evaluated from experimental data taking into account the uncertainty contributions. The tests consisted ...

  3. Diagnostic accuracy of organ electrodermal diagnostics | Szopinski ...

    African Journals Online (AJOL)

    Objective. To estimate the diagnostic accuracy as well as the scope of utilisation of a new bio-electronic method of organ diagnostics. Design. Double-blind comparative study of the diagnostic results obtained by means of organ electrodermal diagnostics (OED) and clinical diagnoses, as a criterion standard. Setting.

  4. Task Speed and Accuracy Decrease When Multitasking

    Science.gov (United States)

    Lin, Lin; Cockerham, Deborah; Chang, Zhengsi; Natividad, Gloria

    2016-01-01

    As new technologies increase the opportunities for multitasking, the need to understand human capacities for multitasking continues to grow stronger. Is multitasking helping us to be more efficient? This study investigated the multitasking abilities of 168 participants, ages 6-72, by measuring their task accuracy and completion time when they…

  5. Content in Context Improves Deception Detection Accuracy

    Science.gov (United States)

    Blair, J. Pete; Levine, Timothy R.; Shaw, Allison S.

    2010-01-01

    Past research has shown that people are only slightly better than chance at distinguishing truths from lies. Higher accuracy rates, however, are possible when contextual knowledge is used to judge the veracity of situated message content. The utility of content in context was shown in a series of experiments with students (N = 26, 45, 51, 25, 127)…

  6. On the accuracy of short read mapping

    DEFF Research Database (Denmark)

    Menzel, Karl Peter; Frellsen, Jes; Plass, Mireya

    2013-01-01

    .e., mapping the reads to a reference genome. In this new situation, conventional alignment tools are obsolete, as they cannot handle this huge amount of data in a reasonable amount of time. Thus, new mapping algorithms have been developed, which are fast at the expense of a small decrease in accuracy...

  7. Studies on the diagnostic accuracy of lymphography

    International Nuclear Information System (INIS)

    Luening, M.; Stargardt, A.; Abet, L.

    1979-01-01

    Contradictory reports in the literature on the reliability of lymphography stimulated the authors to test the diagnostic accuracy, employing methods which are approximately analogous to practice, using carcinoma of the cervix as the model on which the study was carried out. Using 21 observers it was found that there was no correlation between their experience and on-target accuracy of the diagnosis. Good observers obtained an accuracy of 85% with good proportions between sensitivity in the recognition of detail, specificity and readiness to arrive at a decision on the basis of discriminatory ability. With the help of the concept of the ROC curves, the position taken up by the observers in respect of diagnostic decisions, and a complex manner of assessing the various characteristic factors determining diagnostic accuracy, are demonstrated. This form of test, which permits manipulation of different variants of diagnosis, is recommended, among other things, for performance control at the end of training and continuing education courses in other fields of x-ray diagnosis as well. (orig.) [de

  8. Accuracy of Digital vs. Conventional Implant Impressions

    Science.gov (United States)

    Lee, Sang J.; Betensky, Rebecca A.; Gianneschi, Grace E.; Gallucci, German O.

    2015-01-01

    The accuracy of digital impressions greatly influences the clinical viability in implant restorations. The aim of this study is to compare the accuracy of gypsum models acquired from the conventional implant impression to digitally milled models created from direct digitalization by three-dimensional analysis. Thirty gypsum and 30 digitally milled models impressed directly from a reference model were prepared. The models were scanned by a laboratory scanner and 30 STL datasets from each group were imported to an inspection software. The datasets were aligned to the reference dataset by a repeated best fit algorithm and 10 specified contact locations of interest were measured in mean volumetric deviations. The areas were pooled by cusps, fossae, interproximal contacts, horizontal and vertical axes of implant position and angulation. The pooled areas were statistically analysed by comparing each group to the reference model to investigate the mean volumetric deviations accounting for accuracy and standard deviations for precision. Milled models from digital impressions had comparable accuracy to gypsum models from conventional impressions. However, differences in fossae and vertical displacement of the implant position from the gypsum and digitally milled models compared to the reference model, exhibited statistical significance (p<0.001, p=0.020 respectively). PMID:24720423

  9. Analyzing thematic maps and mapping for accuracy

    Science.gov (United States)

    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

  10. Accuracy and conservatism of vapour intrusion algorithms for contaminated land management

    NARCIS (Netherlands)

    Provoost, J.; Reijnders, L.; Bonders, J.

    2013-01-01

    This paper provides a view on the suitability of screening-level vapour intrusion (VI) algorithms for contaminated land management. It focuses on the accuracy and level of conservatism for a number of screening-level algorithms used for VI into buildings. The paper discusses the published evidence

  11. Computed tomography angiogram. Accuracy in renal surgery

    International Nuclear Information System (INIS)

    Rabah, Danny M.; Al-Hathal, Naif; Al-Fuhaid, Turki; Raza, Sayed; Al-Yami, Fahad; Al-Taweel, Waleed; Alomar, Mohamed; Al-Nagshabandi, Nizar

    2009-01-01

    The objective of this study was to determine the sensitivity and specificity of computed tomography angiogram (CTA) in detecting number and location of renal arteries and veins as well as crossing vessels causing uretero-pelvic junction obstruction (UPJO), and to determine if this can be used in decision-making algorithms for treatment of UPJO. A prospective study was carried out in patients undergoing open, laparoscopic and robotic renal surgery from April 2005 until October 2006. All patients were imaged using CTA with 1.25 collimation of arterial and venous phases. Each multi-detector CTA was then read by one radiologist and his results were compared prospectively with the actual intra-operative findings. Overall, 118 patients were included. CTA had 93% sensitivity, 77% specificity and 90% overall accuracy for detecting a single renal artery, and 76% sensitivity, 92% specificity and 90% overall accuracy for detecting two or more renal arteries (Pearson χ 2 =0.001). There was 95% sensitivity, 84% specificity and 85% overall accuracy for detecting the number of renal veins. CTA had 100% overall accuracy in detecting early dividing renal artery (defined as less than 1.5 cm branching from origin), and 83.3% sensitivity, specificity and overall accuracy in detecting crossing vessels at UPJ. The percentage of surgeons stating CTA to be helpful as pre-operative diagnostic tool was 85%. Computed tomography angiogram is simple, quick and can provide an accurate pre-operative renal vascular anatomy in terms of number and location of renal vessels, early dividing renal arteries and crossing vessels at UPJ. (author)

  12. Diagnostic accuracy of MRCP in choledocholithiasis

    International Nuclear Information System (INIS)

    Guarise, Alessandro; Mainardi, Paride; Baltieri, Susanna; Faccioli, Niccolo'

    2005-01-01

    Purpose: To evaluate the accuracy of MRCP in diagnosing choledocholithiasis considering Endoscopic Retrograde Cholangiopancreatography (ERCP) as the gold standard. To compare the results achieved during the first two years of use (1999-2000) of Magnetic Resonance Cholangiopancreatography (MRCP) in patients with suspected choledocholithiasis with those achieved during the following two years (2001-2002) in order to establish the repeatability and objectivity of MRCP results. Materials and methods: One hundred and seventy consecutive patients underwent MRCP followed by ERCP within 72 h. In 22/170 (13%) patients ERCP was unsuccessful for different reasons. MRCP was performed using a 1.5 T magnet with both multi-slice HASTE sequences and thick-slice projection technique. Choledocholithiasis was diagnosed in the presence of signal void images in the dependent portion of the duct surrounded by hyperintense bile and detected at least in two projections. The MRCP results, read independently from the ERCP results, were compared in two different and subsequent periods. Results: ERCP confirmed choledocholithiasis in 87 patients. In these cases the results of MRCP were the following: 78 true positives, 53 true negatives, 7 false positives, and 9 false negatives. The sensitivity, specificity and accuracy were 90%, 88% and 89%, respectively. After the exclusion of stones with diameters smaller than 6 mm, the sensitivity, specificity and accuracy were 100%, 99% and 99%, respectively. MRCP accuracy was related to the size of the stones. There was no significant statistical difference between the results obtained in the first two-year period and those obtained in the second period. Conclusions: MRCP i sufficiently accurate to replace ERCP in patients with suspected choledocholithiasis. The results are related to the size of stones. The use of well-defined radiological signs allows good diagnostic accuracy independent of the learning curve [it

  13. Photon caliper to achieve submillimeter positioning accuracy

    Science.gov (United States)

    Gallagher, Kyle J.; Wong, Jennifer; Zhang, Junan

    2017-09-01

    The purpose of this study was to demonstrate the feasibility of using a commercial two-dimensional (2D) detector array with an inherent detector spacing of 5 mm to achieve submillimeter accuracy in localizing the radiation isocenter. This was accomplished by delivering the Vernier ‘dose’ caliper to a 2D detector array where the nominal scale was the 2D detector array and the non-nominal Vernier scale was the radiation dose strips produced by the high-definition (HD) multileaf collimators (MLCs) of the linear accelerator. Because the HD MLC sequence was similar to the picket fence test, we called this procedure the Vernier picket fence (VPF) test. We confirmed the accuracy of the VPF test by offsetting the HD MLC bank by known increments and comparing the known offset with the VPF test result. The VPF test was able to determine the known offset within 0.02 mm. We also cross-validated the accuracy of the VPF test in an evaluation of couch hysteresis. This was done by using both the VPF test and the ExacTrac optical tracking system to evaluate the couch position. We showed that the VPF test was in agreement with the ExacTrac optical tracking system within a root-mean-square value of 0.07 mm for both the lateral and longitudinal directions. In conclusion, we demonstrated the VPF test can determine the offset between a 2D detector array and the radiation isocenter with submillimeter accuracy. Until now, no method to locate the radiation isocenter using a 2D detector array has been able to achieve such accuracy.

  14. High accuracy FIONA-AFM hybrid imaging

    International Nuclear Information System (INIS)

    Fronczek, D.N.; Quammen, C.; Wang, H.; Kisker, C.; Superfine, R.; Taylor, R.; Erie, D.A.; Tessmer, I.

    2011-01-01

    Multi-protein complexes are ubiquitous and play essential roles in many biological mechanisms. Single molecule imaging techniques such as electron microscopy (EM) and atomic force microscopy (AFM) are powerful methods for characterizing the structural properties of multi-protein and multi-protein-DNA complexes. However, a significant limitation to these techniques is the ability to distinguish different proteins from one another. Here, we combine high resolution fluorescence microscopy and AFM (FIONA-AFM) to allow the identification of different proteins in such complexes. Using quantum dots as fiducial markers in addition to fluorescently labeled proteins, we are able to align fluorescence and AFM information to ≥8 nm accuracy. This accuracy is sufficient to identify individual fluorescently labeled proteins in most multi-protein complexes. We investigate the limitations of localization precision and accuracy in fluorescence and AFM images separately and their effects on the overall registration accuracy of FIONA-AFM hybrid images. This combination of the two orthogonal techniques (FIONA and AFM) opens a wide spectrum of possible applications to the study of protein interactions, because AFM can yield high resolution (5-10 nm) information about the conformational properties of multi-protein complexes and the fluorescence can indicate spatial relationships of the proteins in the complexes. -- Research highlights: → Integration of fluorescent signals in AFM topography with high (<10 nm) accuracy. → Investigation of limitations and quantitative analysis of fluorescence-AFM image registration using quantum dots. → Fluorescence center tracking and display as localization probability distributions in AFM topography (FIONA-AFM). → Application of FIONA-AFM to a biological sample containing damaged DNA and the DNA repair proteins UvrA and UvrB conjugated to quantum dots.

  15. Does filler database size influence identification accuracy?

    Science.gov (United States)

    Bergold, Amanda N; Heaton, Paul

    2018-06-01

    Police departments increasingly use large photo databases to select lineup fillers using facial recognition software, but this technological shift's implications have been largely unexplored in eyewitness research. Database use, particularly if coupled with facial matching software, could enable lineup constructors to increase filler-suspect similarity and thus enhance eyewitness accuracy (Fitzgerald, Oriet, Price, & Charman, 2013). However, with a large pool of potential fillers, such technologies might theoretically produce lineup fillers too similar to the suspect (Fitzgerald, Oriet, & Price, 2015; Luus & Wells, 1991; Wells, Rydell, & Seelau, 1993). This research proposes a new factor-filler database size-as a lineup feature affecting eyewitness accuracy. In a facial recognition experiment, we select lineup fillers in a legally realistic manner using facial matching software applied to filler databases of 5,000, 25,000, and 125,000 photos, and find that larger databases are associated with a higher objective similarity rating between suspects and fillers and lower overall identification accuracy. In target present lineups, witnesses viewing lineups created from the larger databases were less likely to make correct identifications and more likely to select known innocent fillers. When the target was absent, database size was associated with a lower rate of correct rejections and a higher rate of filler identifications. Higher algorithmic similarity ratings were also associated with decreases in eyewitness identification accuracy. The results suggest that using facial matching software to select fillers from large photograph databases may reduce identification accuracy, and provides support for filler database size as a meaningful system variable. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  16. Achieving Climate Change Absolute Accuracy in Orbit

    Science.gov (United States)

    Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G.; Thome, K. J; Leroy, S.; Corliss, J.; Anderson, J. G.; Ao, C. O.; Bantges, R.; Best, F.; hide

    2013-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring and attributing climate change. CLARREO measurements establish new climate change benchmarks with high absolute radiometric accuracy and high statistical confidence across a wide range of essential climate variables. CLARREO's inherently high absolute accuracy will be verified and traceable on orbit to Système Internationale (SI) units. The benchmarks established by CLARREO will be critical for assessing changes in the Earth system and climate model predictive capabilities for decades into the future as society works to meet the challenge of optimizing strategies for mitigating and adapting to climate change. The CLARREO benchmarks are derived from measurements of the Earth's thermal infrared spectrum (5-50 micron), the spectrum of solar radiation reflected by the Earth and its atmosphere (320-2300 nm), and radio occultation refractivity from which accurate temperature profiles are derived. The mission has the ability to provide new spectral fingerprints of climate change, as well as to provide the first orbiting radiometer with accuracy sufficient to serve as the reference transfer standard for other space sensors, in essence serving as a "NIST [National Institute of Standards and Technology] in orbit." CLARREO will greatly improve the accuracy and relevance of a wide range of space-borne instruments for decadal climate change. Finally, CLARREO has developed new metrics and methods for determining the accuracy requirements of climate observations for a wide range of climate variables and uncertainty sources. These methods should be useful for improving our understanding of observing requirements for most climate change observations.

  17. Audiovisual biofeedback improves motion prediction accuracy.

    Science.gov (United States)

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

    2013-04-01

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

  18. Diagnostic Accuracy Comparison of Artificial Immune Algorithms for Primary Headaches

    Directory of Open Access Journals (Sweden)

    Ufuk Çelik

    2015-01-01

    Full Text Available The present study evaluated the diagnostic accuracy of immune system algorithms with the aim of classifying the primary types of headache that are not related to any organic etiology. They are divided into four types: migraine, tension, cluster, and other primary headaches. After we took this main objective into consideration, three different neurologists were required to fill in the medical records of 850 patients into our web-based expert system hosted on our project web site. In the evaluation process, Artificial Immune Systems (AIS were used as the classification algorithms. The AIS are classification algorithms that are inspired by the biological immune system mechanism that involves significant and distinct capabilities. These algorithms simulate the specialties of the immune system such as discrimination, learning, and the memorizing process in order to be used for classification, optimization, or pattern recognition. According to the results, the accuracy level of the classifier used in this study reached a success continuum ranging from 95% to 99%, except for the inconvenient one that yielded 71% accuracy.

  19. Global discriminative learning for higher-accuracy computational gene prediction.

    Directory of Open Access Journals (Sweden)

    Axel Bernal

    2007-03-01

    Full Text Available Most ab initio gene predictors use a probabilistic sequence model, typically a hidden Markov model, to combine separately trained models of genomic signals and content. By combining separate models of relevant genomic features, such gene predictors can exploit small training sets and incomplete annotations, and can be trained fairly efficiently. However, that type of piecewise training does not optimize prediction accuracy and has difficulty in accounting for statistical dependencies among different parts of the gene model. With genomic information being created at an ever-increasing rate, it is worth investigating alternative approaches in which many different types of genomic evidence, with complex statistical dependencies, can be integrated by discriminative learning to maximize annotation accuracy. Among discriminative learning methods, large-margin classifiers have become prominent because of the success of support vector machines (SVM in many classification tasks. We describe CRAIG, a new program for ab initio gene prediction based on a conditional random field model with semi-Markov structure that is trained with an online large-margin algorithm related to multiclass SVMs. Our experiments on benchmark vertebrate datasets and on regions from the ENCODE project show significant improvements in prediction accuracy over published gene predictors that use intrinsic features only, particularly at the gene level and on genes with long introns.

  20. Accuracy Rates of Ancestry Estimation by Forensic Anthropologists Using Identified Forensic Cases.

    Science.gov (United States)

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

    2017-07-01

    A common task in forensic anthropology involves the estimation of the ancestry of a decedent by comparing their skeletal morphology and measurements to skeletons of individuals from known geographic groups. However, the accuracy rates of ancestry estimation methods in actual forensic casework have rarely been studied. This article uses 99 forensic cases with identified skeletal remains to develop accuracy rates for ancestry estimations conducted by forensic anthropologists. The overall rate of correct ancestry estimation from these cases is 90.9%, which is comparable to most research-derived rates and those reported by individual practitioners. Statistical tests showed no significant difference in accuracy rates depending on examiner education level or on the estimated or identified ancestry. More recent cases showed a significantly higher accuracy rate. The incorporation of metric analyses into the ancestry estimate in these cases led to a higher accuracy rate. © 2017 American Academy of Forensic Sciences.

  1. Improving the accuracy of livestock distribution estimates through spatial interpolation.

    Science.gov (United States)

    Bryssinckx, Ward; Ducheyne, Els; Muhwezi, Bernard; Godfrey, Sunday; Mintiens, Koen; Leirs, Herwig; Hendrickx, Guy

    2012-11-01

    Animal distribution maps serve many purposes such as estimating transmission risk of zoonotic pathogens to both animals and humans. The reliability and usability of such maps is highly dependent on the quality of the input data. However, decisions on how to perform livestock surveys are often based on previous work without considering possible consequences. A better understanding of the impact of using different sample designs and processing steps on the accuracy of livestock distribution estimates was acquired through iterative experiments using detailed survey. The importance of sample size, sample design and aggregation is demonstrated and spatial interpolation is presented as a potential way to improve cattle number estimates. As expected, results show that an increasing sample size increased the precision of cattle number estimates but these improvements were mainly seen when the initial sample size was relatively low (e.g. a median relative error decrease of 0.04% per sampled parish for sample sizes below 500 parishes). For higher sample sizes, the added value of further increasing the number of samples declined rapidly (e.g. a median relative error decrease of 0.01% per sampled parish for sample sizes above 500 parishes. When a two-stage stratified sample design was applied to yield more evenly distributed samples, accuracy levels were higher for low sample densities and stabilised at lower sample sizes compared to one-stage stratified sampling. Aggregating the resulting cattle number estimates yielded significantly more accurate results because of averaging under- and over-estimates (e.g. when aggregating cattle number estimates from subcounty to district level, P interpolation to fill in missing values in non-sampled areas, accuracy is improved remarkably. This counts especially for low sample sizes and spatially even distributed samples (e.g. P <0.001 for a sample of 170 parishes using one-stage stratified sampling and aggregation on district level

  2. Precision contact level gauge

    International Nuclear Information System (INIS)

    Krejci, M.; Pilat, M.; Stulik, P.

    1977-01-01

    Equipment was developed measuring the heavy water level in the TR-0 reactor core within an accuracy of several hundredths of a millimeter in a range of around 3.5 m and at a temperature of up to 90 degC. The equipment uses a vibrating needle contact as a high sensitivity level gauge and a servomechanical system with a motion screw carrying the gauge for monitoring and measuring the level in the desired range. The advantage of the unique level gauge consists in that that the transducer converts the measured level position to an electric signal, ie., pulse width, with high sensitivity and without hysteresis. (Kr)

  3. Sentinel-1A/B Combined Product Geolocation Accuracy

    Directory of Open Access Journals (Sweden)

    Adrian Schubert

    2017-06-01

    Full Text Available Sentinel-1A and -1B are twin spaceborne synthetic aperture radar (SAR sensors developed and operated by the European Space Agency under the auspices of the Copernicus Earth observation programme. Launched in April 2014 and April 2016, Sentinel-1A and -1B are currently operating in tandem, in a common orbital configuration to provide an increased revisit frequency. In-orbit commissioning was completed for each unit within months of their respective launches, and level-1 SAR products generated by the operational SAR processor have been geometrically calibrated. In order to compare and monitor the geometric characteristics of the level-1 products from both units, as well as to investigate potential improvements, products from both satellites have been monitored since their respective commissioning phases. In this study, we present geolocation accuracy estimates for both Sentinel-1 units based on the time series of level-1 products collected thus far. While both units were demonstrated to be performing consistently, and providing SAR data products according to the nominal product specifications, a subtle beam- and mode-dependent azimuth bias common to the data from both units was identified. A method for removing the bias is proposed, and the corresponding improvement to the geometric accuracies is demonstrated and quantified.

  4. How to address patients' defences: a pilot study of the accuracy of defence interpretations and alliance.

    Science.gov (United States)

    Junod, Olivier; de Roten, Yves; Martinez, Elena; Drapeau, Martin; Despland, Jean-Nicolas

    2005-12-01

    This pilot study examined the accuracy of therapist defence interpretations (TAD) in high-alliance patients (N = 7) and low-alliance patients (N = 8). TAD accuracy was assessed in the two subgroups by comparing for each case the patient's most frequent defensive level with the most frequent defensive level addressed by the therapist when making defence interpretations. Results show that in high-alliance patient-therapist dyads, the therapists tend to address accurate or higher (more mature) defensive level than patients most frequent level. On the other hand, the therapists address lower (more immature) defensive level in low-alliance dyads. These results are discussed along with possible ways to better assess TAD accuracy.

  5. Evaluating measurement accuracy a practical approach

    CERN Document Server

    Rabinovich, Semyon G

    2013-01-01

    The goal of Evaluating Measurement Accuracy: A Practical Approach is to present methods for estimating the accuracy of measurements performed in industry, trade, and scientific research. From developing the theory of indirect measurements to proposing new methods of reduction, transformation, and enumeration, this work encompasses the full range of measurement data processing. It includes many examples that illustrate the application of general theory to typical problems encountered in measurement practice. As a result, the book serves as an inclusive reference work for data processing of all types of measurements: single and multiple, combined and simultaneous, direct (both linear and nonlinear), and indirect (both dependent and independent). It is a working tool for experimental scientists and engineers of all disciplines who work with instrumentation. It is also a good resource for natural science and engineering students and for technicians performing measurements in industry. A key feature of the book is...

  6. Improving the accuracy of dynamic mass calculation

    Directory of Open Access Journals (Sweden)

    Oleksandr F. Dashchenko

    2015-06-01

    Full Text Available With the acceleration of goods transporting, cargo accounting plays an important role in today's global and complex environment. Weight is the most reliable indicator of the materials control. Unlike many other variables that can be measured indirectly, the weight can be measured directly and accurately. Using strain-gauge transducers, weight value can be obtained within a few milliseconds; such values correspond to the momentary load, which acts on the sensor. Determination of the weight of moving transport is only possible by appropriate processing of the sensor signal. The aim of the research is to develop a methodology for weighing freight rolling stock, which increases the accuracy of the measurement of dynamic mass, in particular wagon that moves. Apart from time-series methods, preliminary filtration for improving the accuracy of calculation is used. The results of the simulation are presented.

  7. Accuracy of clinical diagnosis in knee arthroscopy.

    OpenAIRE

    Brooks, Stuart; Morgan, Mamdouh

    2002-01-01

    A prospective study of 238 patients was performed in a district general hospital to assess current diagnostic accuracy rates and to ascertain the use and the effectiveness of magnetic resonance imaging (MRI) scanning in reducing the number of negative arthroscopies. The pre-operative diagnosis of patients listed for knee arthroscopy was medial meniscus tear 94 (40%) and osteoarthritis 59 (25%). MRI scans were requested in 57 patients (24%) with medial meniscus tear representing 65% (37 patien...

  8. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...

  9. Accuracy of radiocarbon analyses at ANTARES

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E M; Fink, D; Hotchkis, M; Hua, Q; Jacobsen, G; Smith, A M; Tuniz, C [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1997-12-31

    Accuracy in Accelerator Mass Spectroscopy (AMS) measurements, as distinct from precision, requires the application of a number of corrections. Most of these are well known except in extreme circumstances and AMS can deliver radiocarbon results which are both precise and accurate in the 0.5 to 1.0% range. The corrections involved in obtaining final radiocarbon ages are discussed. 3 refs., 1 tab.

  10. Measurement Accuracy Limitation Analysis on Synchrophasors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jiecheng [University of Tennessee (UT); Zhan, Lingwei [University of Tennessee (UT); Liu, Yilu [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Qi, Hairong [University of Tennessee, Knoxville (UTK); Gracia, Jose R [ORNL; Ewing, Paul D [ORNL

    2015-01-01

    This paper analyzes the theoretical accuracy limitation of synchrophasors measurements on phase angle and frequency of the power grid. Factors that cause the measurement error are analyzed, including error sources in the instruments and in the power grid signal. Different scenarios of these factors are evaluated according to the normal operation status of power grid measurement. Based on the evaluation and simulation, the errors of phase angle and frequency caused by each factor are calculated and discussed.

  11. Accuracy of radiocarbon analyses at ANTARES

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M.; Fink, D.; Hotchkis, M.; Hua, Q.; Jacobsen, G.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accuracy in Accelerator Mass Spectroscopy (AMS) measurements, as distinct from precision, requires the application of a number of corrections. Most of these are well known except in extreme circumstances and AMS can deliver radiocarbon results which are both precise and accurate in the 0.5 to 1.0% range. The corrections involved in obtaining final radiocarbon ages are discussed. 3 refs., 1 tab.

  12. Simulation analysis for hyperbola locating accuracy

    International Nuclear Information System (INIS)

    Wang Changli; Liu Daizhi

    2004-01-01

    In the system of the hyperbola location, the geometric shape of the detecting stations has an important influence on the locating accuracy. At first, this paper simulates the process of the hyperbola location by the computer, and then analyzes the influence of the geometric shape on the locating errors and gives the computer simulation results, finally, discusses the problems that require attention in course of selecting the detecting station. The conclusion has practicality. (authors)

  13. On the Accuracy of Language Trees

    Science.gov (United States)

    Pompei, Simone; Loreto, Vittorio; Tria, Francesca

    2011-01-01

    Historical linguistics aims at inferring the most likely language phylogenetic tree starting from information concerning the evolutionary relatedness of languages. The available information are typically lists of homologous (lexical, phonological, syntactic) features or characters for many different languages: a set of parallel corpora whose compilation represents a paramount achievement in linguistics. From this perspective the reconstruction of language trees is an example of inverse problems: starting from present, incomplete and often noisy, information, one aims at inferring the most likely past evolutionary history. A fundamental issue in inverse problems is the evaluation of the inference made. A standard way of dealing with this question is to generate data with artificial models in order to have full access to the evolutionary process one is going to infer. This procedure presents an intrinsic limitation: when dealing with real data sets, one typically does not know which model of evolution is the most suitable for them. A possible way out is to compare algorithmic inference with expert classifications. This is the point of view we take here by conducting a thorough survey of the accuracy of reconstruction methods as compared with the Ethnologue expert classifications. We focus in particular on state-of-the-art distance-based methods for phylogeny reconstruction using worldwide linguistic databases. In order to assess the accuracy of the inferred trees we introduce and characterize two generalizations of standard definitions of distances between trees. Based on these scores we quantify the relative performances of the distance-based algorithms considered. Further we quantify how the completeness and the coverage of the available databases affect the accuracy of the reconstruction. Finally we draw some conclusions about where the accuracy of the reconstructions in historical linguistics stands and about the leading directions to improve it. PMID:21674034

  14. Do Investors Learn About Analyst Accuracy?

    OpenAIRE

    Chang, Charles; Daouk, Hazem; Wang, Albert

    2008-01-01

    We study the impact of analyst forecasts on prices to determine whether investors learn about analyst accuracy. Our test market is the crude oil futures market. Prices rise when analysts forecast a decrease (increase) in crude supplies. In the 15 minutes following supply realizations, prices rise (fall) when forecasts have been too high (low). In both the initial price action relative to forecasts and in the subsequent reaction relative to realized forecast errors, the price response is stron...

  15. On the accuracy of language trees.

    Directory of Open Access Journals (Sweden)

    Simone Pompei

    Full Text Available Historical linguistics aims at inferring the most likely language phylogenetic tree starting from information concerning the evolutionary relatedness of languages. The available information are typically lists of homologous (lexical, phonological, syntactic features or characters for many different languages: a set of parallel corpora whose compilation represents a paramount achievement in linguistics. From this perspective the reconstruction of language trees is an example of inverse problems: starting from present, incomplete and often noisy, information, one aims at inferring the most likely past evolutionary history. A fundamental issue in inverse problems is the evaluation of the inference made. A standard way of dealing with this question is to generate data with artificial models in order to have full access to the evolutionary process one is going to infer. This procedure presents an intrinsic limitation: when dealing with real data sets, one typically does not know which model of evolution is the most suitable for them. A possible way out is to compare algorithmic inference with expert classifications. This is the point of view we take here by conducting a thorough survey of the accuracy of reconstruction methods as compared with the Ethnologue expert classifications. We focus in particular on state-of-the-art distance-based methods for phylogeny reconstruction using worldwide linguistic databases. In order to assess the accuracy of the inferred trees we introduce and characterize two generalizations of standard definitions of distances between trees. Based on these scores we quantify the relative performances of the distance-based algorithms considered. Further we quantify how the completeness and the coverage of the available databases affect the accuracy of the reconstruction. Finally we draw some conclusions about where the accuracy of the reconstructions in historical linguistics stands and about the leading directions to improve

  16. The dimensional accuracy of the sintered billets

    Directory of Open Access Journals (Sweden)

    Чингиз Ариф оглы Алиев

    2016-01-01

    Full Text Available The article presents the results of assessing the impact of the behaviour stability of the components included in the compositions and process parameters of their production, on the dimensional accuracy of workpieces. It was found that by increasing the amount of oxide in the composition is greater compaction of the sintered billet in the process of heat treatment. This also increases the density of all components of the composition

  17. QUALITY LOSS FUNCTION FOR MACHINING PROCESS ACCURACY

    Directory of Open Access Journals (Sweden)

    Adrian Stere PARIS

    2017-05-01

    Full Text Available The main goal of the paper is to propose new quality loss models for machining process accuracy in the classical case “zero the best”, MMF and Harris type. In addition a numerical example illustrates that the choose regression functions are directly linked with the quality loss of manufacturing process. The proposed models can be adapted for the “maximal the best” and “nominal the best” cases.

  18. Accuracy and precision in activation analysis: counting

    International Nuclear Information System (INIS)

    Becker, D.A.

    1974-01-01

    Accuracy and precision in activation analysis was investigated with regard to counting of induced radioactivity. The various parameters discussed include configuration, positioning, density, homogeneity, intensity, radioisotopic purity, peak integration, and nuclear constants. Experimental results are presented for many of these parameters. The results obtained indicate that counting errors often contribute significantly to the inaccuracy and imprecision of analyses. The magnitude of these errors range from less than 1 percent to 10 percent or more in many cases

  19. Ultra-wideband ranging precision and accuracy

    International Nuclear Information System (INIS)

    MacGougan, Glenn; O'Keefe, Kyle; Klukas, Richard

    2009-01-01

    This paper provides an overview of ultra-wideband (UWB) in the context of ranging applications and assesses the precision and accuracy of UWB ranging from both a theoretical perspective and a practical perspective using real data. The paper begins with a brief history of UWB technology and the most current definition of what constitutes an UWB signal. The potential precision of UWB ranging is assessed using Cramer–Rao lower bound analysis. UWB ranging methods are described and potential error sources are discussed. Two types of commercially available UWB ranging radios are introduced which are used in testing. Actual ranging accuracy is assessed from line-of-sight testing under benign signal conditions by comparison to high-accuracy electronic distance measurements and to ranges derived from GPS real-time kinematic positioning. Range measurements obtained in outdoor testing with line-of-sight obstructions and strong reflection sources are compared to ranges derived from classically surveyed positions. The paper concludes with a discussion of the potential applications for UWB ranging

  20. Accuracy of stereolithographic models of human anatomy

    International Nuclear Information System (INIS)

    Barker, T.M.; Earwaker, W.J.S.; Lisle, D.A.

    1994-01-01

    A study was undertaken to determine the dimensional accuracy of anatomical replicas derived from X-ray 3D computed tomography (CT) images and produced using the rapid prototyping technique of stereolithography (SLA). A dry bone skull and geometric phantom were scanned, and replicas were produced. Distance measurements were obtained to compare the original objects and the resulting replicas. Repeated measurements between anatomical landmarks were used for comparison of the original skull and replica. Results for the geometric phantom demonstrate a mean difference of +0.47mm, representing an accuracy of 97.7-99.12%. Measurements of the skull produced a range of absolute differences (maximum +4.62mm, minimum +0.1mm, mean +0.85mm). These results support the use of SLA models of human anatomical structures in such areas as pre-operative planning of complex surgical procedures. For applications where higher accuracy is required, improvements can be expected by utilizing smaller pixel resolution in the CT images. Stereolithographic models can now be confidently employed as accurate, three-dimensional replicas of complex, anatomical structures. 14 refs., 2 tabs., 8 figs

  1. Diagnostic accuracy of sonoelastography in different diseases

    Directory of Open Access Journals (Sweden)

    Iqra Manzoor

    2018-03-01

    Full Text Available The objective of this study was to evaluate the diagnostic accuracy of sonoelastography in patients of primary and secondary health care settings. Google scholar, PubMed, Medline, Medscape, Wikipedia and NCBI were searched in October 2017 for all original studies and review articles to identify the relevant material. Two reviewers independently selected articles for evaluation of the diagnostic accuracy of sonoelastography in different diseases based on titles and abstracts retrieved by the literature search. The accuracy of sonoelastography in different diseases was used as the index text, while B-mode sonography, micro pure imaging, surgery and histological findings were used as reference texts. Superficial lymph nodes, neck nodules, malignancy in thyroid nodules, benign and malignant cervical lymph nodes, thyroid nodules, prostate carcinoma, benign and malignant breast abnormalities, liver diseases, parotid and salivary gland masses, pancreatic masses, musculoskeletal diseases and renal disorders were target conditions. The data extracted by the two reviewers concerning selected study characteristics and results were presented in tables and figures. In total, 46 studies were found for breast masses, lymph nodes, prostate carcinoma, liver diseases, salivary and parotid gland diseases, pancreatic masses, musculoskeletal diseases and renal diseases, and the overall sensitivity of sonoelastography in diagnosing all these diseases was 83.14% while specificity was 81.41%. This literature review demonstrates that sonoelastography is characterized by high sensitivity and specificity in diagnosing different disorders of the body.

  2. Eye movement accuracy determines natural interception strategies.

    Science.gov (United States)

    Fooken, Jolande; Yeo, Sang-Hoon; Pai, Dinesh K; Spering, Miriam

    2016-11-01

    Eye movements aid visual perception and guide actions such as reaching or grasping. Most previous work on eye-hand coordination has focused on saccadic eye movements. Here we show that smooth pursuit eye movement accuracy strongly predicts both interception accuracy and the strategy used to intercept a moving object. We developed a naturalistic task in which participants (n = 42 varsity baseball players) intercepted a moving dot (a "2D fly ball") with their index finger in a designated "hit zone." Participants were instructed to track the ball with their eyes, but were only shown its initial launch (100-300 ms). Better smooth pursuit resulted in more accurate interceptions and determined the strategy used for interception, i.e., whether interception was early or late in the hit zone. Even though early and late interceptors showed equally accurate interceptions, they may have relied on distinct tactics: early interceptors used cognitive heuristics, whereas late interceptors' performance was best predicted by pursuit accuracy. Late interception may be beneficial in real-world tasks as it provides more time for decision and adjustment. Supporting this view, baseball players who were more senior were more likely to be late interceptors. Our findings suggest that interception strategies are optimally adapted to the proficiency of the pursuit system.

  3. Noise pollution mapping approach and accuracy on landscape scales.

    Science.gov (United States)

    Iglesias Merchan, Carlos; Diaz-Balteiro, Luis

    2013-04-01

    Noise mapping allows the characterization of environmental variables, such as noise pollution or soundscape, depending on the task. Strategic noise mapping (as per Directive 2002/49/EC, 2002) is a tool intended for the assessment of noise pollution at the European level every five years. These maps are based on common methods and procedures intended for human exposure assessment in the European Union that could be also be adapted for assessing environmental noise pollution in natural parks. However, given the size of such areas, there could be an alternative approach to soundscape characterization rather than using human noise exposure procedures. It is possible to optimize the size of the mapping grid used for such work by taking into account the attributes of the area to be studied and the desired outcome. This would then optimize the mapping time and the cost. This type of optimization is important in noise assessment as well as in the study of other environmental variables. This study compares 15 models, using different grid sizes, to assess the accuracy of the noise mapping of the road traffic noise at a landscape scale, with respect to noise and landscape indicators. In a study area located in the Manzanares High River Basin Regional Park in Spain, different accuracy levels (Kappa index values from 0.725 to 0.987) were obtained depending on the terrain and noise source properties. The time taken for the calculations and the noise mapping accuracy results reveal the potential for setting the map resolution in line with decision-makers' criteria and budget considerations. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Increase in the Accuracy of Calculating Length of Horizontal Cable SCS in Civil Engineering

    Science.gov (United States)

    Semenov, A.

    2017-11-01

    A modification of the method for calculating the horizontal cable consumption of SCS established at civil engineering facilities is proposed. The proposed procedure preserves the prototype simplicity and provides a 5 percent accuracy increase. The values of the achieved accuracy are justified, their compliance with the practice of real projects is proved. The method is brought to the level of the engineering algorithm and formalized in the form of 12/70 rule.

  5. Investigation of accuracy and computation time of a hierarchy of growth rate definitions

    International Nuclear Information System (INIS)

    Maudlin, P.J.; Borg, R.C.; Ott, K.O.

    1977-07-01

    A numerical illustration of the hierarchy of four logically different procedures for the calculation of the asymptotic growth of fast breeder fuel is presented. Each hierarchy level is analyzed in terms of accuracy and computational effort. Using the first procedure as reference, the fourth procedure, which incorporates the isotopic breeding worths, w vector*, requires a minimum amount of effort with a negligible decrease in accuracy

  6. Requisite accuracy for hot spot factors in fast reactors

    International Nuclear Information System (INIS)

    Miki, Kazuyoshi; Inoue, Kotaro

    1976-01-01

    In the thermal design of a fast reactor, it should be most effective to reduce hot spot factors to the lowest possible level compatible with safety considerations, in order to minimize the design margin for the temperature prevailing in the core. Hot spot factors account for probabilistic and statistic deviations from nominal value of fuel element temperatures, due to uncertainties in the data adopted for estimating various factors including the physical properties. Such temperature deviations necessitate the provision of correspondingly large design margins for temperatures in order to keep within permissible limits the probability of exceeding the allowable temperatures. Evaluation of the desired accuracy for hot spot factors is performed by a method of optimization, which permits determination of the degree of accuracy that should minimize the design margins, to give realistic results with consideration given not only to sensitivity coefficients but also to the present-day uncertainty levels in the data adopted in the calculations. A concept of ''degree of difficulty'' is introduced for the purpose of determining the hot spot factors to be given higher priority for reduction. Application of this method to the core of a prototype fast reactor leads to the conclusion that the hot spot factors to be given the highest priority are those relevant to the power distribution, the flow distribution, the fuel enrichment, the fuel-cladding gap conductance and the fuel thermal conductivity. (auth.)

  7. Testing the accuracy of remote sensing land use maps

    Science.gov (United States)

    Vangenderen, J. L.; Lock, B. F.; Vass, P. A.

    1977-01-01

    Some of the main aspects that need to be considered in a remote sensing sampling design are: (1) the frequency that any one land use type (on the ground) is erroneously attributed to another class by the interpreter; (2) the frequency that the wrong land use (as observed on the ground) is erroneously included in any one class by the remote sensing interpreter; (3) the proportion of all land (as determined in the field) that is mistakenly attributed by the interpreter; and (4) the determination of whether the mistakes are random (so that the overall proportions are approximately correct) or subject to a persistent bias. A sampling and statistical testing procedure is presented which allows an approximate answer to each of these aspects. The concept developed and described incorporates the probability of making incorrect interpretations at particular prescribed accuracy levels, for a certain number of errors, for a particular sample size. It is considered that this approach offers a meaningful explanation of the interpretation accuracy level of an entire remote sensing land use survey.

  8. Accuracy of abdominal auscultation for bowel obstruction.

    Science.gov (United States)

    Breum, Birger Michael; Rud, Bo; Kirkegaard, Thomas; Nordentoft, Tyge

    2015-09-14

    To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction. Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann(®) Electronic Stethoscope. The recordings were processed to yield 25-s sound sequences in random order on PCs. Observers, recruited from doctors within the department, classified the sound sequences as either normal or pathological. The reference tests for bowel obstruction were intraoperative and endoscopic findings and clinical follow up. Sensitivity and specificity were calculated for each observer and compared between junior and senior doctors. Interobserver variation was measured using the Kappa statistic. Bowel sound sequences from 98 patients were assessed by 53 (33 junior and 20 senior) doctors. Laparotomy was performed in 47 patients, 35 of whom had bowel obstruction. Two patients underwent colorectal stenting due to large bowel obstruction. The median sensitivity and specificity was 0.42 (range: 0.19-0.64) and 0.78 (range: 0.35-0.98), respectively. There was no significant difference in accuracy between junior and senior doctors. The median frequency with which doctors classified bowel sounds as abnormal did not differ significantly between patients with and without bowel obstruction (26% vs 23%, P = 0.08). The 53 doctors made up 1378 unique pairs and the median Kappa value was 0.29 (range: -0.15-0.66). Accuracy and inter-observer agreement was generally low. Clinical decisions in patients with possible bowel obstruction should not be based on auscultatory assessment of bowel sounds.

  9. Improving calibration accuracy in gel dosimetry

    International Nuclear Information System (INIS)

    Oldham, M.; McJury, M.; Webb, S.; Baustert, I.B.; Leach, M.O.

    1998-01-01

    A new method of calibrating gel dosimeters (applicable to both Fricke and polyacrylamide gels) is presented which has intrinsically higher accuracy than current methods, and requires less gel. Two test-tubes of gel (inner diameter 2.5 cm, length 20 cm) are irradiated separately with a 10x10cm 2 field end-on in a water bath, such that the characteristic depth-dose curve is recorded in the gel. The calibration is then determined by fitting the depth-dose measured in water, against the measured change in relaxivity with depth in the gel. Increased accuracy is achieved in this simple depth-dose geometry by averaging the relaxivity at each depth. A large number of calibration data points, each with relatively high accuracy, are obtained. Calibration data over the full range of dose (1.6-10 Gy) is obtained by irradiating one test-tube to 10 Gy at dose maximum (D max ), and the other to 4.5 Gy at D max . The new calibration method is compared with a 'standard method' where five identical test-tubes of gel were irradiated to different known doses between 2 and 10 Gy. The percentage uncertainties in the slope and intercept of the calibration fit are found to be lower with the new method by a factor of about 4 and 10 respectively, when compared with the standard method and with published values. The gel was found to respond linearly within the error bars up to doses of 7 Gy, with a slope of 0.233±0.001 s -1 Gy -1 and an intercept of 1.106±0.005 Gy. For higher doses, nonlinear behaviour was observed. (author)

  10. Accuracy Requirements in Medical Radiation Dosimetry

    International Nuclear Information System (INIS)

    Andreo, P.

    2011-01-01

    The need for adopting unambiguous terminology on 'accuracy in medical radiation dosimetry' which is consistent with international recommendations for metrology is emphasized. Uncertainties attainable, or the need for improving their estimates, are analysed for the fields of radiotherapy, diagnostic radiology and nuclear medicine dosimetry. This review centres on uncertainties related to the first step of the dosimetry chain in the three fields, which in all cases involves the use of a detector calibrated by a standards laboratory to determine absorbed dose, air kerma or activity under reference conditions in a clinical environment. (author)

  11. Quantum chemistry by random walk: Higher accuracy

    International Nuclear Information System (INIS)

    Anderson, J.B.

    1980-01-01

    The random walk method of solving the Schroedinger equation is extended to allow the calculation of eigenvalues of atomic and molecular systems with higher accuracy. The combination of direct calculation of the difference delta between a true wave function psi and a trial wave function psi/sub o/ with importance sampling greatly reduces systematic and statistical error. The method is illustrated with calculations for ground-state hydrogen and helium atoms using trial wave functions from variational calculations. The energies obtained are 20 to 100 times more accurate than those of the corresponding variational calculations

  12. ArcticDEM Validation and Accuracy Assessment

    Science.gov (United States)

    Candela, S. G.; Howat, I.; Noh, M. J.; Porter, C. C.; Morin, P. J.

    2017-12-01

    ArcticDEM comprises a growing inventory Digital Elevation Models (DEMs) covering all land above 60°N. As of August, 2017, ArcticDEM had openly released 2-m resolution, individual DEM covering over 51 million km2, which includes areas of repeat coverage for change detection, as well as over 15 million km2 of 5-m resolution seamless mosaics. By the end of the project, over 80 million km2 of 2-m DEMs will be produced, averaging four repeats of the 20 million km2 Arctic landmass. ArcticDEM is produced from sub-meter resolution, stereoscopic imagery using open source software (SETSM) on the NCSA Blue Waters supercomputer. These DEMs have known biases of several meters due to errors in the sensor models generated from satellite positioning. These systematic errors are removed through three-dimensional registration to high-precision Lidar or other control datasets. ArcticDEM is registered to seasonally-subsetted ICESat elevations due its global coverage and high report accuracy ( 10 cm). The vertical accuracy of ArcticDEM is then obtained from the statistics of the fit to the ICESat point cloud, which averages -0.01 m ± 0.07 m. ICESat, however, has a relatively coarse measurement footprint ( 70 m) which may impact the precision of the registration. Further, the ICESat data predates the ArcticDEM imagery by a decade, so that temporal changes in the surface may also impact the registration. Finally, biases may exist between different the different sensors in the ArcticDEM constellation. Here we assess the accuracy of ArcticDEM and the ICESat registration through comparison to multiple high-resolution airborne lidar datasets that were acquired within one year of the imagery used in ArcticDEM. We find the ICESat dataset is performing as anticipated, introducing no systematic bias during the coregistration process, and reducing vertical errors to within the uncertainty of the airborne Lidars. Preliminary sensor comparisons show no significant difference post coregistration

  13. Accuracy of prehospital transport time estimation.

    Science.gov (United States)

    Wallace, David J; Kahn, Jeremy M; Angus, Derek C; Martin-Gill, Christian; Callaway, Clifton W; Rea, Thomas D; Chhatwal, Jagpreet; Kurland, Kristen; Seymour, Christopher W

    2014-01-01

    Estimates of prehospital transport times are an important part of emergency care system research and planning; however, the accuracy of these estimates is unknown. The authors examined the accuracy of three estimation methods against observed transport times in a large cohort of prehospital patient transports. This was a validation study using prehospital records in King County, Washington, and southwestern Pennsylvania from 2002 to 2006 and 2005 to 2011, respectively. Transport time estimates were generated using three methods: linear arc distance, Google Maps, and ArcGIS Network Analyst. Estimation error, defined as the absolute difference between observed and estimated transport time, was assessed, as well as the proportion of estimated times that were within specified error thresholds. Based on the primary results, a regression estimate was used that incorporated population density, time of day, and season to assess improved accuracy. Finally, hospital catchment areas were compared using each method with a fixed drive time. The authors analyzed 29,935 prehospital transports to 44 hospitals. The mean (± standard deviation [±SD]) absolute error was 4.8 (±7.3) minutes using linear arc, 3.5 (±5.4) minutes using Google Maps, and 4.4 (±5.7) minutes using ArcGIS. All pairwise comparisons were statistically significant (p Google Maps, and 11.6 [±10.9] minutes for ArcGIS). Estimates were within 5 minutes of observed transport time for 79% of linear arc estimates, 86.6% of Google Maps estimates, and 81.3% of ArcGIS estimates. The regression-based approach did not substantially improve estimation. There were large differences in hospital catchment areas estimated by each method. Route-based transport time estimates demonstrate moderate accuracy. These methods can be valuable for informing a host of decisions related to the system organization and patient access to emergency medical care; however, they should be employed with sensitivity to their limitations.

  14. Accuracy in Robot Generated Image Data Sets

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Dahl, Anders Bjorholm

    2015-01-01

    In this paper we present a practical innovation concerning how to achieve high accuracy of camera positioning, when using a 6 axis industrial robots to generate high quality data sets for computer vision. This innovation is based on the realization that to a very large extent the robots positioning...... error is deterministic, and can as such be calibrated away. We have successfully used this innovation in our efforts for creating data sets for computer vision. Since the use of this innovation has a significant effect on the data set quality, we here present it in some detail, to better aid others...

  15. Accuracy of colonoscopy in localizing colonic cancer.

    Science.gov (United States)

    Stanciu, C; Trifan, Anca; Khder, Saad Alla

    2007-01-01

    It is important to establish the precise localization of colonic cancer preoperatively; while colonoscopy is regarded as the diagnostic gold standard for colorectal cancer, its ability to localize the tumor is less reliable. To define the accuracy of colonoscopy in identifying the location of colonic cancer. All of the patients who had a colorectal cancer diagnosed by colonoscopy at the Institute of Gastroenterology and Hepatology, Iaşi and subsequently received a surgical intervention at three teaching hospitals in Iaşi, between January 2001 and December 2005, were included in this study. Endoscopic records and operative notes were carefully reviewed, and tumor localization was recorded. There were 161 patients (89 men, 72 women, aged 61.3 +/- 12.8 years) who underwent conventional surgery for colon cancer detected by colonoscopy during the study period. Twenty-two patients (13.66%) had erroneous colonoscopic localization of the tumors. The overall accuracy of preoperative colonoscopic localization was 87.58%. Colonoscopy is an accurate, reliable method for locating colon cancer, although additional techniques (i.e., endoscopic tattooing) should be performed at least for small lesions.

  16. Accuracy requirements in radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Buzdar, S. A.; Afzal, M.; Nazir, A.; Gadhi, M. A.

    2013-01-01

    Radiation therapy attempts to deliver ionizing radiation to the tumour and can improve the survival chances and/or quality of life of patients. There are chances of errors and uncertainties in the entire process of radiotherapy that may affect the accuracy and precision of treatment management and decrease degree of conformation. All expected inaccuracies, like radiation dose determination, volume calculation, complete evaluation of the full extent of the tumour, biological behaviour of specific tumour types, organ motion during radiotherapy, imaging, biological/molecular uncertainties, sub-clinical diseases, microscopic spread of the disease, uncertainty in normal tissue responses and radiation morbidity need sound appreciation. Conformity can be increased by reduction of such inaccuracies. With the yearly increase in computing speed and advancement in other technologies the future will provide the opportunity to optimize a greater number of variables and reduce the errors in the treatment planning process. In multi-disciplined task of radiotherapy, efforts are needed to overcome the errors and uncertainty, not only by the physicists but also by radiologists, pathologists and oncologists to reduce molecular and biological uncertainties. The radiation therapy physics is advancing towards an optimal goal that is definitely to improve accuracy where necessary and to reduce uncertainty where possible. (author)

  17. High accuracy satellite drag model (HASDM)

    Science.gov (United States)

    Storz, Mark F.; Bowman, Bruce R.; Branson, Major James I.; Casali, Stephen J.; Tobiska, W. Kent

    The dominant error source in force models used to predict low-perigee satellite trajectories is atmospheric drag. Errors in operational thermospheric density models cause significant errors in predicted satellite positions, since these models do not account for dynamic changes in atmospheric drag for orbit predictions. The Air Force Space Battlelab's High Accuracy Satellite Drag Model (HASDM) estimates and predicts (out three days) a dynamically varying global density field. HASDM includes the Dynamic Calibration Atmosphere (DCA) algorithm that solves for the phases and amplitudes of the diurnal and semidiurnal variations of thermospheric density near real-time from the observed drag effects on a set of Low Earth Orbit (LEO) calibration satellites. The density correction is expressed as a function of latitude, local solar time and altitude. In HASDM, a time series prediction filter relates the extreme ultraviolet (EUV) energy index E10.7 and the geomagnetic storm index ap, to the DCA density correction parameters. The E10.7 index is generated by the SOLAR2000 model, the first full spectrum model of solar irradiance. The estimated and predicted density fields will be used operationally to significantly improve the accuracy of predicted trajectories for all low-perigee satellites.

  18. Fast and High Accuracy Wire Scanner

    CERN Document Server

    Koujili, M; Koopman, J; Ramos, D; Sapinski, M; De Freitas, J; Ait Amira, Y; Djerdir, A

    2009-01-01

    Scanning of a high intensity particle beam imposes challenging requirements on a Wire Scanner system. It is expected to reach a scanning speed of 20 m.s-1 with a position accuracy of the order of 1 μm. In addition a timing accuracy better than 1 millisecond is needed. The adopted solution consists of a fork holding a wire rotating by a maximum of 200°. Fork, rotor and angular position sensor are mounted on the same axis and located in a chamber connected to the beam vacuum. The requirements imply the design of a system with extremely low vibration, vacuum compatibility, radiation and temperature tolerance. The adopted solution consists of a rotary brushless synchronous motor with the permanent magnet rotor installed inside of the vacuum chamber and the stator installed outside. The accurate position sensor will be mounted on the rotary shaft inside of the vacuum chamber, has to resist a bake-out temperature of 200°C and ionizing radiation up to a dozen of kGy/year. A digital feedback controller allows maxi...

  19. Accuracy of magnetic resonance based susceptibility measurements

    Science.gov (United States)

    Erdevig, Hannah E.; Russek, Stephen E.; Carnicka, Slavka; Stupic, Karl F.; Keenan, Kathryn E.

    2017-05-01

    Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Accurate measurements of susceptibility are important for determining oxygen and iron content in blood vessels and brain tissue for use in noninvasive clinical diagnosis and treatment assessments. Induced magnetic fields with amplitude on the order of 100 nT, can be detected using MRI phase images. The induced field distributions can then be inverted to obtain quantitative susceptibility maps. The focus of this research was to determine the accuracy of MRI-based susceptibility measurements using simple phantom geometries and to compare the susceptibility measurements with magnetometry measurements where SI-traceable standards are available. The susceptibilities of paramagnetic salt solutions in cylindrical containers were measured as a function of orientation relative to the static MRI field. The observed induced fields as a function of orientation of the cylinder were in good agreement with simple models. The MRI susceptibility measurements were compared with SQUID magnetometry using NIST-traceable standards. MRI can accurately measure relative magnetic susceptibilities while SQUID magnetometry measures absolute magnetic susceptibility. Given the accuracy of moment measurements of tissue mimicking samples, and the need to look at small differences in tissue properties, the use of existing NIST standard reference materials to calibrate MRI reference structures is problematic and better reference materials are required.

  20. Diatomic molecule vibrational potentials: Accuracy of representations

    International Nuclear Information System (INIS)

    Engelke, R.

    1978-01-01

    A method is presented for increasing the radius of convergence of certain representations of diatomic molecule vibrational potentials. The method relies on using knowledge of the analytic structure of such potentials to the maximum when attempting to approximate them. The known singular point (due to the centrifugal and/or Coulomb potentials) at zero internuclear separation should be included in its exact form in an approximate representation. The efficacy of this idea is tested [using Peek's ''exact'' numerical Born-Oppenheimer potential for the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2 as a test problem] when the representational form is the series of (1) Dunham, (2) Simons, Parr, and Finlan, (3) Thakkar, and (4) Ogilvie-Tipping, and also (5) when the form is a [2, 2] or a [3, 3] Pade approximant. Significant improvements in accuracy are obtained in some of these cases, particularly on the inner wall of the potential. A comparison of the effectiveness of the five methods is made both with and without the origin behavior being included exactly. This is useful in itself as no comprehensive accuracy comparison of the standard representations seems to have appeared in the literature. The Ogilvie-Tipping series, corrected at the origin for singular behavior, is the best representation presently available for states analogous to the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2

  1. Dimensional accuracy of 3D printed vertebra

    Science.gov (United States)

    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.

  2. Accuracy assessment of landslide prediction models

    International Nuclear Information System (INIS)

    Othman, A N; Mohd, W M N W; Noraini, S

    2014-01-01

    The increasing population and expansion of settlements over hilly areas has greatly increased the impact of natural disasters such as landslide. Therefore, it is important to developed models which could accurately predict landslide hazard zones. Over the years, various techniques and models have been developed to predict landslide hazard zones. The aim of this paper is to access the accuracy of landslide prediction models developed by the authors. The methodology involved the selection of study area, data acquisition, data processing and model development and also data analysis. The development of these models are based on nine different landslide inducing parameters i.e. slope, land use, lithology, soil properties, geomorphology, flow accumulation, aspect, proximity to river and proximity to road. Rank sum, rating, pairwise comparison and AHP techniques are used to determine the weights for each of the parameters used. Four (4) different models which consider different parameter combinations are developed by the authors. Results obtained are compared to landslide history and accuracies for Model 1, Model 2, Model 3 and Model 4 are 66.7, 66.7%, 60% and 22.9% respectively. From the results, rank sum, rating and pairwise comparison can be useful techniques to predict landslide hazard zones

  3. Diagnostic accuracy of fluorescence microlymphography for detecting limb lymphedema.

    Science.gov (United States)

    Keo, H H; Husmann, M; Groechenig, E; Willenberg, T; Gretener, S B

    2015-04-01

    Fluorescence microlymphography (FML) is a minimally invasive technique for visualization of the cutaneous lymphatic network. The aim of the study was to assess the accuracy and safety of FML in patients with unilateral lymphedema. This was a cross sectional study. Patients with unilateral leg swelling were assessed and compared with the unaffected contralateral limb. FML was performed in all index legs and the contralateral leg by injecting 0.1 mL of fluorescein isothiocyanate (FITC)-labeled dextran intradermally in both limbs at the same level. The most prominent swelling of the affected limb was the anatomical reference. The spread of the dye in the lymphatic capillaries of the skin was measured in all dimensions by epiluminator intravital microscopy and the maximum dye spread value 10 min after injection was used for statistical analysis. The contralateral leg served as control. Test accuracy and receiver operator characteristic (ROC) analysis was performed to assess threshold values that best predict lymphedema. Between March 2008 and February 2014 seventy patients with unilateral chronic leg swelling were clinically diagnosed with lymphedema. The median age was 45 (IQR 27-56) years. Of those, 46 (65.7%) were female and 71.4% had primary and 28.6% secondary lymphedema. Sensitivity, specificity, positive and negative likelihood ratio, and positive and negative predictive value were 94.3%, 78.6%, 4.40, 0.07, 81.5%, and 93.2% for the 12 mm cut off level and 91.4%, 85.7%, 6.40, 0.10, 86.5%, and 90.9% for the 14 mm cut off level, respectively. The area under the ROC curve was 0.89 (95% CI: 0.83-0.95). No major adverse events were observed. FML is an almost atraumatic and safe technique for detecting lymphedema in patients with leg swelling. In this series the greatest accuracy was observed at a cut off level of ≥14 mm maximum spread. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  4. Temporal subtraction in chest radiography: Automated assessment of registration accuracy

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Croteau, Charles L.; MacMahon, Heber

    2006-01-01

    Radiologists routinely compare multiple chest radiographs acquired from the same patient over time to more completely understand changes in anatomy and pathology. While such comparisons are achieved conventionally through a side-by-side display of images, image registration techniques have been developed to combine information from two separate radiographic images through construction of a 'temporal subtraction image'. Although temporal subtraction images provide a powerful mechanism for the enhanced visualization of subtle change, errors in the clinical evaluation of these images may arise from misregistration artifacts that can mimic or obscure pathologic change. We have developed a computerized method for the automated assessment of registration accuracy as demonstrated in temporal subtraction images created from radiographic chest image pairs. The registration accuracy of 150 temporal subtraction images constructed from the computed radiography images of 72 patients was rated manually using a five-point scale ranging from '5-excellent' to '1-poor'; ratings of 3, 4, or 5 reflected clinically acceptable subtraction images, and ratings of 1 or 2 reflected clinically unacceptable images. Gray-level histogram-based features and texture measures are computed at multiple spatial scales within a 'lung mask' region that encompasses both lungs in the temporal subtraction images. A subset of these features is merged through a linear discriminant classifier. With a leave-one-out-by-patient training/testing paradigm, the automated method attained an A z value of 0.92 in distinguishing between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. A second linear discriminant classifier yielded an A z value of 0.82 based on a feature subset selected from an independent database of digitized film images. These methods are expected to advance the clinical utility of temporal subtraction images for chest

  5. Diagnostic accuracy of slit skin smears in leprosy

    International Nuclear Information System (INIS)

    Naveed, T.; Shaikh, Z.

    2015-01-01

    To determine the diagnostic accuracy of slit skin smears in clinically suspected patients of leprosy using histopathology as gold standard. Study Design: Validation study Place and Duration of Study: Study was carried out at Rawalpindi Leprosy Hospital, Dermatology Department Military Hospital (MH) and Armed Forces Institute of Pathology (AFIP), Rawalpindi from 18th August 2012 to 18 Feb 2013. Methods: Appropriate technical and ethical approval for the study and patient consent were obtained. All suspected patients of leprosy of any age and either gender having typical hypo-aesthetic or anesthetic, erythematous or hypo-pigmented scaly skin lesions on any part of body were included in this study. All patients who have already received treatment for leprosy, patients with pure neural leprosy, patient not giving their consent for skin biopsy and patients with lepra reactions were excluded from this study. Forty eight patients fulfilling the inclusion criteria were included in the study. Sample size had been calculated by using WHO sample size calculator taking confidence level 95%, absolute precision required 14% and anticipated population proportion 40%. Non-probability consecutive sampling technique was used to collect sample. Results: The results of the study revealed that out of 48 clinically suspected patients of leprosy skin biopsy confirmed the diagnosis in 34 patients (70.8%) and the slit skin smear had diagnostic accuracy of 68.75% with sensitivity 55.8% and specificity and positive predictive value of 100%. Conclusion: Study suggested that although slit skin smears are rapid and inexpensive method of diagnosis but their diagnostic accuracy is low. (author)

  6. Measuring Adolescent Self-Awareness and Accuracy Using a Performance-Based Assessment and Parental Report

    Directory of Open Access Journals (Sweden)

    Sharon Zlotnik

    2018-02-01

    Full Text Available AimThe aim of this study was to assess awareness of performance and performance accuracy for a task that requires executive functions (EF, among healthy adolescents and to compare their performance to their parent’s ratings.MethodParticipants: 109 healthy adolescents (mean age 15.2 ± 1.86 years completed the Weekly Calendar Planning Activity (WCPA. The discrepancy between self-estimated and actual performance was used to measure the level of awareness. The participants were divided into high and low accuracy groups according to the WCPA accuracy median score. The participants were also divided into high and low awareness groups. A comparison was conducted between groups using WCPA performance and parent ratings on the Behavior Rating Inventory of Executive Function (BRIEF.ResultsHigher awareness was associated with better EF performance. Participants with high accuracy scores were more likely to show high awareness of performance as compared to participants with low accuracy scores. The high accuracy group had better parental ratings of EF, higher efficiency, followed more rules, and were more aware of their WCPA performance.ConclusionOur results highlight the important contribution that self-awareness of performance may have on the individual’s function. Assessing the level of awareness and providing metacognitive training techniques for those adolescents who are less aware, could support their performance.

  7. Accuracy of computer-assisted orthognathic surgery.

    Science.gov (United States)

    De Riu, Giacomo; Virdis, Paola Ilaria; Meloni, Silvio Mario; Lumbau, Aurea; Vaira, Luigi Angelo

    2018-02-01

    The purpose of this study was to retrospectively evaluate the difference between the planned and the actual movements of the jaws, using three-dimensional (3D) software for PC-assisted orthognathic surgery, to establish the accuracy of the procedure. A retrospective study was performed with 49 patients who had undergone PC-guided bimaxillary surgery. The accuracy of the protocol was determined by comparing planned movements of the jaws with the actual surgical movements, analysing frontal and lateral cephalometries. The overall results were deemed accurate, and differences among 12 of the 15 parameters were considered nonsignificant. Significant differences were reported for SNA (p = 0.008), SNB (p = 0.006), and anterior facial height (p = 0.033). The latter was significantly different in patients who had undergone genioplasty when compared with patients who had not. Virtual surgical planning presented a good degree of accuracy for most of the parameters assessed, with an average error of 1.98 mm for linear measures and 1.19° for angular measures. In general, a tendency towards under-projection in jaws was detected, probably due to imperfect condylar seating. A slight overcorrection of SNA and SNB during virtual planning (approximately 2°) could be beneficial. Further progress is required in the development of 3D simulation of the soft tissue, which currently does not allow an accurate management of the facial height and the chin position. Virtual planning cannot replace the need for constant intraoperative monitoring of the jaws' movements and real-time comparisons between planned and actual outcomes. It is therefore appropriate to leave some margin for correction of inaccuracies in the virtual planning. In this sense, it may be appropriate to use only the intermediate splint, and then use the planned occlusion and clinical measurements to guide repositioning of the second jaw and chin, respectively. Copyright © 2017 European Association for Cranio

  8. Accuracy of CNV Detection from GWAS Data.

    Directory of Open Access Journals (Sweden)

    Dandan Zhang

    2011-01-01

    Full Text Available 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.

  9. Systematic Review of the Diagnostic Accuracy and Therapeutic Effectiveness of Sacroiliac Joint Interventions.

    Science.gov (United States)

    Simopoulos, Thomas T; Manchikanti, Laxmaiah; Gupta, Sanjeeva; Aydin, Steve M; Kim, Chong Hwan; Solanki, Daneshvari; Nampiaparampil, Devi E; Singh, Vijay; Staats, Peter S; Hirsch, Joshua A

    2015-01-01

    The sacroiliac joint is well known as a cause of low back and lower extremity pain. Prevalence estimates are 10% to 25% in patients with persistent axial low back pain without disc herniation, discogenic pain, or radiculitis based on multiple diagnostic studies and systematic reviews. However, at present there are no definitive management options for treating sacroiliac joint pain. To evaluate the diagnostic accuracy and therapeutic effectiveness of sacroiliac joint interventions. A systematic review of the diagnostic accuracy and therapeutic effectiveness of sacroiliac joint interventions. The available literature on diagnostic and therapeutic sacroiliac joint interventions was reviewed. The quality assessment criteria utilized were the Quality Appraisal of Reliability Studies (QAREL) checklist for diagnostic accuracy studies, Cochrane review criteria to assess sources of risk of bias, and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) criteria for randomized therapeutic trials and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR) for observational therapeutic assessments. The level of evidence was based on a best evidence synthesis with modified grading of qualitative evidence from Level I to Level V. Data sources included relevant literature published from 1966 through March 2015 that were identified through searches of PubMed and EMBASE, manual searches of the bibliographies of known primary and review articles, and all other sources. For the diagnostic accuracy assessment, and for the therapeutic modalities, the primary outcome measure of pain relief and improvement in functional status were utilized. A total of 11 diagnostic accuracy studies and 14 therapeutic studies were included. The evidence for diagnostic accuracy is Level II for dual diagnostic blocks with at least 70% pain relief as the criterion

  10. Assessing the Accuracy and Readability of Online Health Information for Patients With Pancreatic Cancer.

    Science.gov (United States)

    Storino, Alessandra; Castillo-Angeles, Manuel; Watkins, Ammara A; Vargas, Christina; Mancias, Joseph D; Bullock, Andrea; Demirjian, Aram; Moser, A James; Kent, Tara S

    2016-09-01

    The degree to which patients are empowered by written educational materials depends on the text's readability level and the accuracy of the information provided. The association of a website's affiliation or focus on treatment modality with its readability and accuracy has yet to be thoroughly elucidated. To compare the readability and accuracy of patient-oriented online resources for pancreatic cancer by treatment modality and website affiliation. An online search of 50 websites discussing 5 pancreatic cancer treatment modalities (alternative therapy, chemotherapy, clinical trials, radiation therapy, and surgery) was conducted. The website's affiliation was identified. Readability was measured by 9 standardized tests, and accuracy was assessed by an expert panel. Nine standardized tests were used to compute the median readability level of each website. The median readability scores were compared among treatment modality and affiliation categories. Accuracy was determined by an expert panel consisting of 2 medical specialists and 2 surgical specialists. The 4 raters independently evaluated all websites belonging to the 5 treatment modalities (a score of 1 indicates that readability and accuracy based on the focus of the treatment modality and the website's affiliation. Websites discussing surgery (with a median readability level of 13.7 and an interquartile range [IQR] of 11.9-15.6) were easier to read than those discussing radiotherapy (median readability level, 15.2 [IQR, 13.0-17.0]) (P = .003) and clinical trials (median readability level, 15.2 [IQR, 12.8-17.0]) (P = .002). Websites of nonprofit organizations (median readability level, 12.9 [IQR, 11.2-15.0]) were easier to read than media (median readability level, 16.0 [IQR, 13.4-17.0]) (P readability level, 14.8 [IQR, 12.9-17.0]) (P readability level, 14.0 [IQR, 12.1-16.1]) were easier to read than media websites (P = .001). Among treatment modalities, alternative therapy websites exhibited the

  11. An Analysis of the Influence of Fundamental Values' Estimation Accuracy on Financial Markets

    Directory of Open Access Journals (Sweden)

    Hiroshi Takahashi

    2010-01-01

    Full Text Available This research analyzed the influence of the differences in the forecast accuracy of fundamental values on the financial market. As a result of intensive experiments in the market, we made the following interesting findings: (1 improvements in forecast accuracy of fundamentalists can contribute to an increase in the number of fundamentalists; (2 certain situations might occur, according to the level of forecast accuracy of fundamentalists, in which fundamentalists and passive management coexist, or in which fundamentalists die out of the market, and furthermore; (3 where a variety of investors exist in the market, improvements in the forecast accuracy could increase the number of fundamentalists more than the number of investors that employ passive investment strategy. These results contribute to clarifying the mechanism of price fluctuations in financial markets and also indicate one of the factors for the low ratio of passive investors in asset management business.

  12. Tracing light propagation to the intrinsic accuracy of spacetime geometry

    International Nuclear Information System (INIS)

    Crosta, Mariateresa

    2011-01-01

    Advancement in astronomical observations requires codification of light propagation and of the processes of its physical measurement at a high level of accuracy. This could unveil a new window of several subtle relativistic effects suffered by light while propagating. Indeed, light modeling and its subsequent detection should be conceived in a fully relativistic context, in order to interpret the outcome of the observing process in accordance with the geometrical environment affecting light propagation itself and the precepts of measurement. This paper deals with the complexity of such a topic by showing how the geometrical framework of RAMOD, a relativistic model initially developed for astrometric observations in the visible, constitutes an appropriate environment for back-tracing photons. Through gauging the energy content of a given gravitationally bound system, the geometrical aspects that match the required accuracy of present and future observational capabilities are evidenced. Then, by comparing different formulations of the null geodesic, their domain of validity within the given geometrical scheme is refined. Finally, by proving its ability in retrieving recent literature cases, RAMOD is promoted as a measurement-based general relativistic method for any present and future advancement in the light-tracing problem. (paper)

  13. Assessment of Sr-90 in water samples: precision and accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Nisti, Marcelo B.; Saueia, Cátia H.R.; Castilho, Bruna; Mazzilli, Barbara P., E-mail: mbnisti@ipen.br, E-mail: chsaueia@ipen.br, E-mail: bcastilho@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accidents in Fukushima Daiichi Nuclear Power Plant and Chernobyl Nuclear Power Plant, released several radionuclides in the environment by aerial deposition and liquid discharge, with various level of radioactivity. The {sup 90}Sr was one of the elements released into the environment. The {sup 90}Sr is produced by nuclear fission with a physical half-life of 28.79 years with decay energy of 0.546 MeV. The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of {sup 90}Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using {sup 90}Sr standard solutions. (author)

  14. Improving Machining Accuracy of CNC Machines with Innovative Design Methods

    Science.gov (United States)

    Yemelyanov, N. V.; Yemelyanova, I. V.; Zubenko, V. L.

    2018-03-01

    The article considers achieving the machining accuracy of CNC machines by applying innovative methods in modelling and design of machining systems, drives and machine processes. The topological method of analysis involves visualizing the system as matrices of block graphs with a varying degree of detail between the upper and lower hierarchy levels. This approach combines the advantages of graph theory and the efficiency of decomposition methods, it also has visual clarity, which is inherent in both topological models and structural matrices, as well as the resiliency of linear algebra as part of the matrix-based research. The focus of the study is on the design of automated machine workstations, systems, machines and units, which can be broken into interrelated parts and presented as algebraic, topological and set-theoretical models. Every model can be transformed into a model of another type, and, as a result, can be interpreted as a system of linear and non-linear equations which solutions determine the system parameters. This paper analyses the dynamic parameters of the 1716PF4 machine at the stages of design and exploitation. Having researched the impact of the system dynamics on the component quality, the authors have developed a range of practical recommendations which have enabled one to reduce considerably the amplitude of relative motion, exclude some resonance zones within the spindle speed range of 0...6000 min-1 and improve machining accuracy.

  15. Assessment of Sr-90 in water samples: precision and accuracy

    International Nuclear Information System (INIS)

    Nisti, Marcelo B.; Saueia, Cátia H.R.; Castilho, Bruna; Mazzilli, Barbara P.

    2017-01-01

    The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accidents in Fukushima Daiichi Nuclear Power Plant and Chernobyl Nuclear Power Plant, released several radionuclides in the environment by aerial deposition and liquid discharge, with various level of radioactivity. The 90 Sr was one of the elements released into the environment. The 90 Sr is produced by nuclear fission with a physical half-life of 28.79 years with decay energy of 0.546 MeV. The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of 90 Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using 90 Sr standard solutions. (author)

  16. Dimensional accuracy of aluminium extrusions in mechanical calibration

    Science.gov (United States)

    Raknes, Christian Arne; Welo, Torgeir; Paulsen, Frode

    2018-05-01

    Reducing dimensional variations in the extrusion process without increasing cost is challenging due to the nature of the process itself. An alternative approach—also from a cost perspective—is using extruded profiles with standard tolerances and utilize downstream processes, and thus calibrate the part within tolerance limits that are not achievable directly from the extrusion process. In this paper, two mechanical calibration strategies for the extruded product are investigated, utilizing the forming lines of the manufacturer. The first calibration strategy is based on global, longitudinal stretching in combination with local bending, while the second strategy utilizes the principle of transversal stretching and local bending of the cross-section. An extruded U-profile is used to make a comparison between the two methods using numerical analyses. To provide response surfaces with the FEA program, ABAQUS is used in combination with Design of Experiment (DOE). DOE is conducted with a two-level fractional factorial design to collect the appropriate data. The aim is to find the main factors affecting the dimension accuracy of the final part obtained by the two calibration methods. The results show that both calibration strategies have proven to reduce cross-sectional variations effectively form standard extrusion tolerances. It is concluded that mechanical calibration is a viable, low-cost alternative for aluminium parts that demand high dimensional accuracy, e.g. due to fit-up or welding requirements.

  17. Climate Change Observation Accuracy: Requirements and Economic Value

    Science.gov (United States)

    Wielicki, Bruce; Cooke, Roger; Golub, Alexander; Baize, Rosemary; Mlynczak, Martin; Lukashin, Constantin; Thome, Kurt; Shea, Yolanda; Kopp, Greg; Pilewskie, Peter; hide

    2016-01-01

    This presentation will summarize a new quantitative approach to determining the required accuracy for climate change observations. Using this metric, most current global satellite observations struggle to meet this accuracy level. CLARREO (Climate Absolute Radiance and Refractivity Observatory) is a new satellite mission designed to resolve this challenge is by achieving advances of a factor of 10 for reflected solar spectra and a factor of 3 to 5 for thermal infrared spectra. The CLARREO spectrometers can serve as SI traceable benchmarks for the Global Satellite Intercalibration System (GSICS) and greatly improve the utility of a wide range of LEO and GEO infrared and reflected solar satellite sensors for climate change observations (e.g. CERES, MODIS, VIIIRS, CrIS, IASI, Landsat, etc). A CLARREO Pathfinder mission for flight on the International Space Station is included in the U.S. Presidentâ€"TM"s fiscal year 2016 budget, with launch in 2019 or 2020. Providing more accurate decadal change trends can in turn lead to more rapid narrowing of key climate science uncertainties such as cloud feedback and climate sensitivity. A new study has been carried out to quantify the economic benefits of such an advance and concludes that the economic value is $9 Trillion U.S. dollars. The new value includes the cost of carbon emissions reductions.

  18. Accuracy of surgical wound drainage measurements: an analysis and comparison.

    Science.gov (United States)

    Yue, Brian; Nizzero, Danielle; Zhang, Chunxiao; van Zyl, Natasha; Ting, Jeannette

    2015-05-01

    Surgical drain tube readings can influence the clinical management of the post-operative patient. The accuracy of these readings has not been documented in the current literature and this experimental study aims to address this paucity. Aliquots (10, 25, 40 and 90 mL) of black tea solution prepared to mimic haemoserous fluid were injected into UnoVac, RedoVac and Jackson-Pratt drain tubes. Nursing and medical staff from a tertiary hospital were asked to estimate drain volumes by direct observation; analysis of variance was performed on the results and significance level was set at 0.05. Doctors and nurses are equally accurate in estimating drain tube volumes. Jackson-Pratt systems were found to be the most accurate for intermediate volumes of 25 and 40 mL. For extreme of volumes (both high and low), all drainage systems were inaccurate. This study suggests that for intermediate volumes (25 and 40 mL), Jackson-Pratt is the drainage system of choice. The accuracy of volume measurement is diminished at the extremes of drain volumes; emptying of drainage systems is recommended to avoid overfilling of drainage systems. © 2014 Royal Australasian College of Surgeons.

  19. Prognostic accuracy of electroencephalograms in preterm infants

    DEFF Research Database (Denmark)

    Fogtmann, Emilie Pi; Plomgaard, Anne Mette; Greisen, Gorm

    2017-01-01

    CONTEXT: Brain injury is common in preterm infants, and predictors of neurodevelopmental outcome are relevant. OBJECTIVE: To assess the prognostic test accuracy of the background activity of the EEG recorded as amplitude-integrated EEG (aEEG) or conventional EEG early in life in preterm infants...... for predicting neurodevelopmental outcome. DATA SOURCES: The Cochrane Library, PubMed, Embase, and the Cumulative Index to Nursing and Allied Health Literature. STUDY SELECTION: We included observational studies that had obtained an aEEG or EEG within 7 days of life in preterm infants and reported...... neurodevelopmental outcomes 1 to 10 years later. DATA EXTRACTION: Two reviewers independently performed data extraction with regard to participants, prognostic testing, and outcomes. RESULTS: Thirteen observational studies with a total of 1181 infants were included. A metaanalysis was performed based on 3 studies...

  20. Accuracy of hazardous waste project estimates

    International Nuclear Information System (INIS)

    Hackney, J.W.

    1989-01-01

    The HAZRATE system has been developed to appraise the current state of definition of hazardous waste remedial projects. This is shown to have a high degree of correlation to the financial risk of such projects. The method employs a weighted checklist indicating the current degree of definition of some 150 significant project elements. It is based on the author's experience with a similar system for establishing the risk characteristics of process plant projects (Hackney, 1965 and 1989; 1985). In this paper definition ratings for 15 hazardous waste remedial projects have been correlated with the excesses of their actual costs over their base estimates, excluding any allowances for contingencies. Equations are presented, based on this study, for computation of the contingency allowance needed and estimate accuracy possible at a given stage of project development

  1. Quantum mechanical calculations to chemical accuracy

    Science.gov (United States)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.

    1991-01-01

    The accuracy of current molecular-structure calculations is illustrated with examples of quantum mechanical solutions for chemical problems. Two approaches are considered: (1) the coupled-cluster singles and doubles (CCSD) with a perturbational estimate of the contribution of connected triple excitations, or CCDS(T); and (2) the multireference configuration-interaction (MRCI) approach to the correlation problem. The MRCI approach gains greater applicability by means of size-extensive modifications such as the averaged-coupled pair functional approach. The examples of solutions to chemical problems include those for C-H bond energies, the vibrational frequencies of O3, identifying the ground state of Al2 and Si2, and the Lewis-Rayleigh afterglow and the Hermann IR system of N2. Accurate molecular-wave functions can be derived from a combination of basis-set saturation studies and full configuration-interaction calculations.

  2. Quantitative code accuracy evaluation of ISP33

    Energy Technology Data Exchange (ETDEWEB)

    Kalli, H.; Miwrrin, A. [Lappeenranta Univ. of Technology (Finland); Purhonen, H. [VTT Energy, Lappeenranta (Finland)] [and others

    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.

  3. Comparative diagnostic accuracy in virtual dermatopathology

    DEFF Research Database (Denmark)

    Mooney, E.; Hood, A.F.; Lampros, J.

    2011-01-01

    studies comparing the diagnostic accuracy and acceptability of virtual slides compared to traditional glass slides. Methods: Ten Nordic dermatopathologists and pathologists were given a randomized combination of 20 virtual and glass slides and asked to identify the diagnoses. They were then asked to give...... their impressions about the virtual images. Descriptive data analysis and comparison of groups using Fisher's exact test were performed. Objective: To compare the diagnostic ability of dermatopathologists and pathologists in two image formats: the traditional (glass) microscopic slides, and whole mount digitized...... of virtual or glass slides did not affect the percentage of questions answered correctly. Seven of nine participants completing the questionnaire, felt virtual microscopy is useful for both learning and testing. Conclusion: There was no significant difference in the participants' diagnostic ability using...

  4. The Accuracy of GBM GRB Localizations

    Science.gov (United States)

    Briggs, Michael Stephen; Connaughton, V.; Meegan, C.; Hurley, K.

    2010-03-01

    We report an study of the accuracy of GBM GRB localizations, analyzing three types of localizations: those produced automatically by the GBM Flight Software on board GBM, those produced automatically with ground software in near real time, and localizations produced with human guidance. The two types of automatic locations are distributed in near real-time via GCN Notices; the human-guided locations are distributed on timescale of many minutes or hours using GCN Circulars. This work uses a Bayesian analysis that models the distribution of the GBM total location error by comparing GBM locations to more accurate locations obtained with other instruments. Reference locations are obtained from Swift, Super-AGILE, the LAT, and with the IPN. We model the GBM total location errors as having systematic errors in addition to the statistical errors and use the Bayesian analysis to constrain the systematic errors.

  5. THE ACCURACY OF Hβ CCD PHOTOMETRY

    Directory of Open Access Journals (Sweden)

    C. Kim

    1994-12-01

    Full Text Available We have undertaken CCD observations of field standard stars with Hβ photometric system to investigate the reliability of Hβ CCD photometry. Flat fielding with dome flat and sky flat for Hβw and Hβn filter was compared with that of B filter in UBV system and, from these, we have not found any difference. It was confirmed that there is a good linear relationship between our Hβ values observed with 2.3m reflector and standard values. However, Hβ values observed with 60cm reflector at Sobaeksan Astronomy Observatory showed very poor relationship. To investigate the accuracy of Hβ CCD photometry for fainter objects, open cluster NGC2437 was observed and reduced with DoPHOT, and the results were compared with those for photoelectric photometry of Stetson (1981.

  6. High current high accuracy IGBT pulse generator

    International Nuclear Information System (INIS)

    Nesterov, V.V.; Donaldson, A.R.

    1995-05-01

    A solid state pulse generator capable of delivering high current triangular or trapezoidal pulses into an inductive load has been developed at SLAC. Energy stored in a capacitor bank of the pulse generator is switched to the load through a pair of insulated gate bipolar transistors (IGBT). The circuit can then recover the remaining energy and transfer it back to the capacitor bank without reversing the capacitor voltage. A third IGBT device is employed to control the initial charge to the capacitor bank, a command charging technique, and to compensate for pulse to pulse power losses. The rack mounted pulse generator contains a 525 μF capacitor bank. It can deliver 500 A at 900V into inductive loads up to 3 mH. The current amplitude and discharge time are controlled to 0.02% accuracy by a precision controller through the SLAC central computer system. This pulse generator drives a series pair of extraction dipoles

  7. Accuracy verification methods theory and algorithms

    CERN Document Server

    Mali, Olli; Repin, Sergey

    2014-01-01

    The importance of accuracy verification methods was understood at the very beginning of the development of numerical analysis. Recent decades have seen a rapid growth of results related to adaptive numerical methods and a posteriori estimates. However, in this important area there often exists a noticeable gap between mathematicians creating the theory and researchers developing applied algorithms that could be used in engineering and scientific computations for guaranteed and efficient error control.   The goals of the book are to (1) give a transparent explanation of the underlying mathematical theory in a style accessible not only to advanced numerical analysts but also to engineers and students; (2) present detailed step-by-step algorithms that follow from a theory; (3) discuss their advantages and drawbacks, areas of applicability, give recommendations and examples.

  8. Accuracy of CT-guided biopsies in 158 patients with thoracic spinal lesions

    International Nuclear Information System (INIS)

    Hao, D.J.; He, B.R.; Liu, T.J.; Zhao, Q.P.; Sun, H.H.; Jiang, Y.H.

    2011-01-01

    Background. Inconsistent accuracies of CT-guided thoracic spinal biopsies have been reported in previous studies. Purpose. To determine the accuracy of CT-guided thoracic spinal biopsy, to compare the results with those previously reported, and to determine if there are any factors that influence the accuracy of CT-guided thoracic spinal biopsy. Material and Methods. In total, 158 consecutive CT-guided percutaneous thoracic spine procedures (performed at the Dept. of Spinal Surgery, Xian Red Cross Hospital between April 2000 and July 2010) were reviewed. The 158 lesions were categorized by location and radiographic features. Pathological and clinical follow-up were used to determine accuracy. Results. The diagnostic accuracy of CT-guided thoracic spinal biopsy was 90.5% overall. Biopsy of metastatic bone disease (98.2%) was significantly more accurate than biopsies of primary tumors (80.9%) and of hematological malignancies (47.0%) (P < 0.05 and P < 0.005, respectively). The diagnostic accuracy of CT-guided thoracic spinal biopsy was significantly higher for the lower thoracic spine (97.6%) than for the middle (90.0%) or upper thoracic spine (80.4%) (P < 0.05 and P < 0.025, respectively). The diagnostic accuracy was significantly higher for lytic lesions (96.4%) than for sclerotic lesions (81.3%) (P < 0.010). The accuracy of biopsies performed using the transpedicular approach (91.0%) was not significantly different from that of biopsies performed using posterolateral approaches (91.5%) (0.25 < P < 0.5). Conclusion. Percutaneous CT-guided thoracic spinal biopsy is a viable alternative to open surgical biopsy. The diagnostic accuracy was not affected by any of the variables except for lesion level, histology, and radiographic features

  9. Accuracy of CT-guided biopsies in 158 patients with thoracic spinal lesions

    Energy Technology Data Exchange (ETDEWEB)

    Hao, D.J.; He, B.R.; Liu, T.J.; Zhao, Q.P. (Dept. of Spinal Surgery, Xian Red Cross Hospital, Xian Shaanxi (China)), email: zqpddn1@gmail.com; Sun, H.H. (Dept. of Orthopaedic, Tangdu Hospital, Fourth Military Medical Univ., Xian Shaanxi (China)); Jiang, Y.H. (Dept. of Radiology, Xian Red Cross Hospital, Xian Shaanxi (China))

    2011-11-15

    Background. Inconsistent accuracies of CT-guided thoracic spinal biopsies have been reported in previous studies. Purpose. To determine the accuracy of CT-guided thoracic spinal biopsy, to compare the results with those previously reported, and to determine if there are any factors that influence the accuracy of CT-guided thoracic spinal biopsy. Material and Methods. In total, 158 consecutive CT-guided percutaneous thoracic spine procedures (performed at the Dept. of Spinal Surgery, Xian Red Cross Hospital between April 2000 and July 2010) were reviewed. The 158 lesions were categorized by location and radiographic features. Pathological and clinical follow-up were used to determine accuracy. Results. The diagnostic accuracy of CT-guided thoracic spinal biopsy was 90.5% overall. Biopsy of metastatic bone disease (98.2%) was significantly more accurate than biopsies of primary tumors (80.9%) and of hematological malignancies (47.0%) (P < 0.05 and P < 0.005, respectively). The diagnostic accuracy of CT-guided thoracic spinal biopsy was significantly higher for the lower thoracic spine (97.6%) than for the middle (90.0%) or upper thoracic spine (80.4%) (P < 0.05 and P < 0.025, respectively). The diagnostic accuracy was significantly higher for lytic lesions (96.4%) than for sclerotic lesions (81.3%) (P < 0.010). The accuracy of biopsies performed using the transpedicular approach (91.0%) was not significantly different from that of biopsies performed using posterolateral approaches (91.5%) (0.25 < P < 0.5). Conclusion. Percutaneous CT-guided thoracic spinal biopsy is a viable alternative to open surgical biopsy. The diagnostic accuracy was not affected by any of the variables except for lesion level, histology, and radiographic features

  10. Classification Accuracy Increase Using Multisensor Data Fusion

    Science.gov (United States)

    Makarau, A.; Palubinskas, G.; Reinartz, P.

    2011-09-01

    The practical use of very high resolution visible and near-infrared (VNIR) data is still growing (IKONOS, Quickbird, GeoEye-1, etc.) but for classification purposes the number of bands is limited in comparison to full spectral imaging. These limitations may lead to the confusion of materials such as different roofs, pavements, roads, etc. and therefore may provide wrong interpretation and use of classification products. Employment of hyperspectral data is another solution, but their low spatial resolution (comparing to multispectral data) restrict their usage for many applications. Another improvement can be achieved by fusion approaches of multisensory data since this may increase the quality of scene classification. Integration of Synthetic Aperture Radar (SAR) and optical data is widely performed for automatic classification, interpretation, and change detection. In this paper we present an approach for very high resolution SAR and multispectral data fusion for automatic classification in urban areas. Single polarization TerraSAR-X (SpotLight mode) and multispectral data are integrated using the INFOFUSE framework, consisting of feature extraction (information fission), unsupervised clustering (data representation on a finite domain and dimensionality reduction), and data aggregation (Bayesian or neural network). This framework allows a relevant way of multisource data combination following consensus theory. The classification is not influenced by the limitations of dimensionality, and the calculation complexity primarily depends on the step of dimensionality reduction. Fusion of single polarization TerraSAR-X, WorldView-2 (VNIR or full set), and Digital Surface Model (DSM) data allow for different types of urban objects to be classified into predefined classes of interest with increased accuracy. The comparison to classification results of WorldView-2 multispectral data (8 spectral bands) is provided and the numerical evaluation of the method in comparison to

  11. Local indicators of geocoding accuracy (LIGA: theory and application

    Directory of Open Access Journals (Sweden)

    Jacquez Geoffrey M

    2009-10-01

    Full Text Available Abstract Background Although sources of positional error in geographic locations (e.g. geocoding error used for describing and modeling spatial patterns are widely acknowledged, research on how such error impacts the statistical results has been limited. In this paper we explore techniques for quantifying the perturbability of spatial weights to different specifications of positional error. Results We find that a family of curves describes the relationship between perturbability and positional error, and use these curves to evaluate sensitivity of alternative spatial weight specifications to positional error both globally (when all locations are considered simultaneously and locally (to identify those locations that would benefit most from increased geocoding accuracy. We evaluate the approach in simulation studies, and demonstrate it using a case-control study of bladder cancer in south-eastern Michigan. Conclusion Three results are significant. First, the shape of the probability distributions of positional error (e.g. circular, elliptical, cross has little impact on the perturbability of spatial weights, which instead depends on the mean positional error. Second, our methodology allows researchers to evaluate the sensitivity of spatial statistics to positional accuracy for specific geographies. This has substantial practical implications since it makes possible routine sensitivity analysis of spatial statistics to positional error arising in geocoded street addresses, global positioning systems, LIDAR and other geographic data. Third, those locations with high perturbability (most sensitive to positional error and high leverage (that contribute the most to the spatial weight being considered will benefit the most from increased positional accuracy. These are rapidly identified using a new visualization tool we call the LIGA scatterplot. Herein lies a paradox for spatial analysis: For a given level of positional error increasing sample density

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

    Science.gov (United States)

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

    2013-01-01

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

  13. Evaluating the Quality, Accuracy, and Readability of Online Resources Pertaining to Hallux Valgus.

    Science.gov (United States)

    Tartaglione, Jason P; Rosenbaum, Andrew J; Abousayed, Mostafa; Hushmendy, Shazaan F; DiPreta, John A

    2016-02-01

    The Internet is one of the most widely utilized resources for health-related information. Evaluation of the medical literature suggests that the quality and accuracy of these resources are poor and written at inappropriately high reading levels. The purpose of our study was to evaluate the quality, accuracy, and readability of online resources pertaining to hallux valgus. Two search terms ("hallux valgus" and "bunion") were entered into Google, Yahoo, and Bing. With the use of scoring criteria specific to hallux valgus, the quality and accuracy of online information related to hallux valgus was evaluated by 3 reviewers. The Flesch-Kincaid score was used to determine readability. Statistical analysis was performed with t tests and significance was determined by P values hallux valgus" (P = .045). Quality and accuracy were significantly higher in resources authored by physicians as compared to nonphysicians (quality, P = .04; accuracy, P hallux valgus is poor and written at inappropriate reading levels. Furthermore, the search term used, authorship, and presence of commercial bias influence the value of these materials. It is important for orthopaedic surgeons to become familiar with patient education materials, so that appropriate recommendations can be made regarding valuable resources. Level IV. © 2015 The Author(s).

  14. Higgs boson decay into b-quarks at NNLO accuracy

    Science.gov (United States)

    Del Duca, Vittorio; Duhr, Claude; Somogyi, Gábor; Tramontano, Francesco; Trócsányi, Zoltán

    2015-04-01

    We compute the fully differential decay rate of the Standard Model Higgs boson into b-quarks at next-to-next-to-leading order (NNLO) accuracy in αs. We employ a general subtraction scheme developed for the calculation of higher order perturbative corrections to QCD jet cross sections, which is based on the universal infrared factorization properties of QCD squared matrix elements. We show that the subtractions render the various contributions to the NNLO correction finite. In particular, we demonstrate analytically that the sum of integrated subtraction terms correctly reproduces the infrared poles of the two-loop double virtual contribution to this process. We present illustrative differential distributions obtained by implementing the method in a parton level Monte Carlo program. The basic ingredients of our subtraction scheme, used here for the first time to compute a physical observable, are universal and can be employed for the computation of more involved processes.

  15. Higgs boson decay into b-quarks at NNLO accuracy

    CERN Document Server

    Del Duca, Vittorio; Somogyi, Gábor; Tramontano, Francesco; Trócsányi, Zoltán

    2015-01-01

    We compute the fully differential decay rate of the Standard Model Higgs boson into b-quarks at next-to-next-to-leading order (NNLO) accuracy in alpha_S. We employ a general subtraction scheme developed for the calculation of higher order perturbative corrections to QCD jet cross sections, which is based on the universal infrared factorization properties of QCD squared matrix elements. We show that the subtractions render the various contributions to the NNLO correction finite. In particular, we demonstrate analytically that the sum of integrated subtraction terms correctly reproduces the infrared poles of the two-loop double virtual contribution to this process. We present illustrative differential distributions obtained by implementing the method in a parton level Monte Carlo program. The basic ingredients of our subtraction scheme, used here for the first time to compute a physical observable, are universal and can be employed for the computation of more involved processes.

  16. Higgs boson decay into b-quarks at NNLO accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Duca, Vittorio Del [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati,Via E. Fermi 40, I-00044 Frascati (Italy); Duhr, Claude [PH Department, TH Unit, CERN,CH-1211 Geneva 23 (Switzerland); Center for Cosmology, Particle Physics and Phenomenology (CP3),Université Catholique de Louvain, Chemin du Cyclotron 2,B-1348 Louvain-La-Neuve (Belgium); Somogyi, Gábor [University of Debrecen and MTA-DE Particle Physics Research Group,H-4010 Debrecen, PO Box 105 (Hungary); Tramontano, Francesco [Dipartimento di Fisica, Università degli studi di Napoli andINFN - Sezione di Napoli, 80125 Napoli (Italy); Trócsányi, Zoltán [University of Debrecen and MTA-DE Particle Physics Research Group,H-4010 Debrecen, PO Box 105 (Hungary)

    2015-04-08

    We compute the fully differential decay rate of the Standard Model Higgs boson into b-quarks at next-to-next-to-leading order (NNLO) accuracy in α{sub s}. We employ a general subtraction scheme developed for the calculation of higher order perturbative corrections to QCD jet cross sections, which is based on the universal infrared factorization properties of QCD squared matrix elements. We show that the subtractions render the various contributions to the NNLO correction finite. In particular, we demonstrate analytically that the sum of integrated subtraction terms correctly reproduces the infrared poles of the two-loop double virtual contribution to this process. We present illustrative differential distributions obtained by implementing the method in a parton level Monte Carlo program. The basic ingredients of our subtraction scheme, used here for the first time to compute a physical observable, are universal and can be employed for the computation of more involved processes.

  17. The effect of letter string length and report condition on letter recognition accuracy.

    Science.gov (United States)

    Raghunandan, Avesh; Karmazinaite, Berta; Rossow, Andrea S

    Letter sequence recognition accuracy has been postulated to be limited primarily by low-level visual factors. The influence of high level factors such as visual memory (load and decay) has been largely overlooked. This study provides insight into the role of these factors by investigating the interaction between letter sequence recognition accuracy, letter string length and report condition. Letter sequence recognition accuracy for trigrams and pentagrams were measured in 10 adult subjects for two report conditions. In the complete report condition subjects reported all 3 or all 5 letters comprising trigrams and pentagrams, respectively. In the partial report condition, subjects reported only a single letter in the trigram or pentagram. Letters were presented for 100ms and rendered in high contrast, using black lowercase Courier font that subtended 0.4° at the fixation distance of 0.57m. Letter sequence recognition accuracy was consistently higher for trigrams compared to pentagrams especially for letter positions away from fixation. While partial report increased recognition accuracy in both string length conditions, the effect was larger for pentagrams, and most evident for the final letter positions within trigrams and pentagrams. The effect of partial report on recognition accuracy for the final letter positions increased as eccentricity increased away from fixation, and was independent of the inner/outer position of a letter. Higher-level visual memory functions (memory load and decay) play a role in letter sequence recognition accuracy. There is also suggestion of additional delays imposed on memory encoding by crowded letter elements. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  18. Aspects of precision and accuracy in neutron activation analysis

    International Nuclear Information System (INIS)

    Heydorn, K.

    1980-03-01

    Analytical results without systematic errors and with accurately known random errors are normally distributed around their true values. Such results may be produced by means of neutron activation analysis both with and without radiochemical separation. When all sources of random variation are known a priori, their effect may be combined with the Poisson statistics characteristic of the counting process, and the standard deviation of a single analytical result may be estimated. The various steps of a complete neutron activation analytical procedure are therefore studied in detail with respect to determining their contribution to the overall variability of the final result. Verification of the estimated standard deviation is carried out by demonstrating the absence of significant unknown random errors through analysing, in replicate, samples covering the range of concentrations and matrices anticipated in actual use. Agreement between the estimated and the observed variability of replicate results is then tested by a simple statistic T based on the chi-square distribution. It is found that results from neutron activation analysis on biological samples can be brought into statistical control. In routine application of methods in statistical control the same statistical test may be used for quality control when some of the actual samples are analysed in duplicate. This analysis of precision serves to detect unknown or unexpected sources of variation of the analytical results, and both random and systematic errors have been discovered in practical trace element investigations in different areas of research. Particularly, at the ultratrace level of concentration where there are few or no standard reference materials for ascertaining the accuracy of results, the proposed quality control based on the analysis of precision combined with neutron activation analysis with radiochemical separation, with an a priori precision independent of the level of concentration, becomes a

  19. Matter power spectrum and the challenge of percent accuracy

    International Nuclear Information System (INIS)

    Schneider, Aurel; Teyssier, Romain; Potter, Doug; Stadel, Joachim; Reed, Darren S.; Onions, Julian; Pearce, Frazer R.; Smith, Robert E.; Springel, Volker; Scoccimarro, Roman

    2016-01-01

    Future galaxy surveys require one percent precision in the theoretical knowledge of the power spectrum over a large range including very nonlinear scales. While this level of accuracy is easily obtained in the linear regime with perturbation theory, it represents a serious challenge for small scales where numerical simulations are required. In this paper we quantify the precision of present-day N -body methods, identifying main potential error sources from the set-up of initial conditions to the measurement of the final power spectrum. We directly compare three widely used N -body codes, Ramses, Pkdgrav3, and Gadget3 which represent three main discretisation techniques: the particle-mesh method, the tree method, and a hybrid combination of the two. For standard run parameters, the codes agree to within one percent at k ≤1 h Mpc −1 and to within three percent at k ≤10 h Mpc −1 . We also consider the bispectrum and show that the reduced bispectra agree at the sub-percent level for k ≤ 2 h Mpc −1 . In a second step, we quantify potential errors due to initial conditions, box size, and resolution using an extended suite of simulations performed with our fastest code Pkdgrav3. We demonstrate that the simulation box size should not be smaller than L =0.5 h −1 Gpc to avoid systematic finite-volume effects (while much larger boxes are required to beat down the statistical sample variance). Furthermore, a maximum particle mass of M p =10 9 h −1 M ⊙ is required to conservatively obtain one percent precision of the matter power spectrum. As a consequence, numerical simulations covering large survey volumes of upcoming missions such as DES, LSST, and Euclid will need more than a trillion particles to reproduce clustering properties at the targeted accuracy.

  20. Matter power spectrum and the challenge of percent accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Aurel; Teyssier, Romain; Potter, Doug; Stadel, Joachim; Reed, Darren S. [Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, 8057 Zurich (Switzerland); Onions, Julian; Pearce, Frazer R. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Smith, Robert E. [Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH (United Kingdom); Springel, Volker [Heidelberger Institut für Theoretische Studien, 69118 Heidelberg (Germany); Scoccimarro, Roman, E-mail: aurel@physik.uzh.ch, E-mail: teyssier@physik.uzh.ch, E-mail: dpotter@physik.uzh.ch, E-mail: stadel@physik.uzh.ch, E-mail: julian.onions@nottingham.ac.uk, E-mail: reed@physik.uzh.ch, E-mail: r.e.smith@sussex.ac.uk, E-mail: volker.springel@h-its.org, E-mail: Frazer.Pearce@nottingham.ac.uk, E-mail: rs123@nyu.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, NY 10003, New York (United States)

    2016-04-01

    Future galaxy surveys require one percent precision in the theoretical knowledge of the power spectrum over a large range including very nonlinear scales. While this level of accuracy is easily obtained in the linear regime with perturbation theory, it represents a serious challenge for small scales where numerical simulations are required. In this paper we quantify the precision of present-day N -body methods, identifying main potential error sources from the set-up of initial conditions to the measurement of the final power spectrum. We directly compare three widely used N -body codes, Ramses, Pkdgrav3, and Gadget3 which represent three main discretisation techniques: the particle-mesh method, the tree method, and a hybrid combination of the two. For standard run parameters, the codes agree to within one percent at k ≤1 h Mpc{sup −1} and to within three percent at k ≤10 h Mpc{sup −1}. We also consider the bispectrum and show that the reduced bispectra agree at the sub-percent level for k ≤ 2 h Mpc{sup −1}. In a second step, we quantify potential errors due to initial conditions, box size, and resolution using an extended suite of simulations performed with our fastest code Pkdgrav3. We demonstrate that the simulation box size should not be smaller than L =0.5 h {sup −1}Gpc to avoid systematic finite-volume effects (while much larger boxes are required to beat down the statistical sample variance). Furthermore, a maximum particle mass of M {sub p}=10{sup 9} h {sup −1}M{sub ⊙} is required to conservatively obtain one percent precision of the matter power spectrum. As a consequence, numerical simulations covering large survey volumes of upcoming missions such as DES, LSST, and Euclid will need more than a trillion particles to reproduce clustering properties at the targeted accuracy.

  1. The accuracy of home glucose meters in hypoglycemia.

    Science.gov (United States)

    Sonmez, Alper; Yilmaz, Zeynep; Uckaya, Gokhan; Kilic, Selim; Tapan, Serkan; Taslipinar, Abdullah; Aydogdu, Aydogan; Yazici, Mahmut; Yilmaz, Mahmut Ilker; Serdar, Muhittin; Erbil, M Kemal; Kutlu, Mustafa

    2010-08-01

    Home glucose meters (HGMs) may not be accurate enough to sense hypoglycemia. We evaluated the accuracy and the capillary and venous comparability of five different HGMs (Optium Xceed [Abbott Diabetes Care, Alameda, CA, USA], Contour TS [Bayer Diabetes Care, Basel, Switzerland], Accu-Chek Go [Roche Ltd., Basel, Switzerland], OneTouch Select [Lifescan, Milpitas, CA, USA], and EZ Smart [Tyson Bioresearch Inc., Chu-Nan, Taiwan]) in an adult population. The insulin hypoglycemia test was performed to 59 subjects (56 males; 23.6 +/- 3.2 years old). Glucose was measured from forearm venous blood and finger capillary samples both before and after regular insulin (0.1 U/kg) was injected. Venous samples were analyzed in the reference laboratory by the hexokinase method. In vitro tests for method comparison and precision analyses were also performed by spiking the glucose-depleted venous blood. All HGMs failed to sense hypoglycemia to some extend. EZ Smart was significantly inferior in critical error Zone D, and OneTouch Select was significantly inferior in the clinically unimportant error Zone B. Accu-Chek Go, Optium Xceed, and Contour TS had similar performances and were significantly better than the other two HGMs according to error grid analysis or International Organization for Standardization criteria. The in vitro tests were consistent with the above clinical data. The capillary and venous consistencies of Accu-Chek Go and OneTouch Select were better than the other HGMs. The present results show that not all the HGMs are accurate enough in low blood glucose levels. The patients and the caregivers should be aware of these restrictions of the HGMs and give more credit to the symptoms of hypoglycemia than the values obtained by the HGMs. Finally, these results indicate that there is a need for the revision of the accuracy standards of HGMs in low blood glucose levels.

  2. Treatment accuracy of fractionated stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Kumar, Shaleen; Burke, Kevin; Nalder, Colin; Jarrett, Paula; Mubata, Cephas; A'Hern, Roger; Humphreys, Mandy; Bidmead, Margaret; Brada, Michael

    2005-01-01

    Background and purpose: To assess the geometric accuracy of the delivery of fractionated stereotactic radiotherapy (FSRT) for brain tumours using the Gill-Thomas-Cosman (GTC) relocatable frame. Accuracy of treatment delivery was measured via portal images acquired with an amorphous silicon based electronic portal imager (EPI). Results were used to assess the existing verification process and to review the current margins used for the expansion of clinical target volume (CTV) to planning target volume (PTV). Patients and methods: Patients were immobilized in a GTC frame. Target volume definition was performed on localization CT and MRI scans and a CTV to PTV margin of 5 mm (based on initial experience) was introduced in 3D. A Brown-Roberts-Wells (BRW) fiducial system was used for stereotactic coordinate definition. The existing verification process consisted of an intercomparison of the coordinates of the isocentres and anatomy between the localization and verification CT scans. Treatment was delivered with 6 MV photons using four fixed non-coplanar conformal fields using a multi-leaf collimator. Portal imaging verification consisted of the acquisition of orthogonal images centred through the treatment isocentre. Digitally reconstructed radiographs (DRRs) created from the CT localization scans were used as reference images. Semi-automated matching software was used to quantify set up deviations (displacements and rotations) between reference and portal images. Results: One hundred and twenty six anterior and 123 lateral portal images were available for analysis for set up deviations. For displacements, the total errors in the cranial/caudal direction were shown to have the largest SD's of 1.2 mm, while systematic and random errors reached SD's of 1.0 and 0.7 mm, respectively, in the cranial/caudal direction. The corresponding data for rotational errors (the largest deviation was found in the sagittal plane) was 0.7 deg. SD (total error), 0.5 deg. (systematic) and 0

  3. Trust in automation and meta-cognitive accuracy in NPP operating crews

    Energy Technology Data Exchange (ETDEWEB)

    Skraaning Jr, G.; Miberg Skjerve, A. B. [OECD Halden Reactor Project, PO Box 173, 1751 Halden (Norway)

    2006-07-01

    Nuclear power plant operators can over-trust or under-trust automation. Operator trust in automation is said to be mis-calibrated when the level of trust is not corresponding to the actual level of automation reliability. A possible consequence of mis-calibrated trust is degraded meta-cognitive accuracy. Meta-cognitive accuracy is the ability to correctly monitor the effectiveness of ones own performance while engaged in complex tasks. When operators misjudge their own performance, human control actions will be poorly regulated and safety and/or efficiency may suffer. An analysis of simulator data showed that meta-cognitive accuracy and trust in automation were highly correlated for knowledge-based scenarios, but uncorrelated for rule-based scenarios. In the knowledge-based scenarios, the operators overestimated their performance effectiveness under high levels of trust, they underestimated performance under low levels of trust, but showed realistic self-assessment under intermediate levels of trust in automation. The result was interpreted to suggest that trust in automation impact the meta-cognitive accuracy of the operators. (authors)

  4. Trust in automation and meta-cognitive accuracy in NPP operating crews

    International Nuclear Information System (INIS)

    Skraaning Jr, G.; Miberg Skjerve, A. B.

    2006-01-01

    Nuclear power plant operators can over-trust or under-trust automation. Operator trust in automation is said to be mis-calibrated when the level of trust is not corresponding to the actual level of automation reliability. A possible consequence of mis-calibrated trust is degraded meta-cognitive accuracy. Meta-cognitive accuracy is the ability to correctly monitor the effectiveness of ones own performance while engaged in complex tasks. When operators misjudge their own performance, human control actions will be poorly regulated and safety and/or efficiency may suffer. An analysis of simulator data showed that meta-cognitive accuracy and trust in automation were highly correlated for knowledge-based scenarios, but uncorrelated for rule-based scenarios. In the knowledge-based scenarios, the operators overestimated their performance effectiveness under high levels of trust, they underestimated performance under low levels of trust, but showed realistic self-assessment under intermediate levels of trust in automation. The result was interpreted to suggest that trust in automation impact the meta-cognitive accuracy of the operators. (authors)

  5. Diagnostic accuracy of language sample measures with Persian-speaking preschool children.

    Science.gov (United States)

    Kazemi, Yalda; Klee, Thomas; Stringer, Helen

    2015-04-01

    This study examined the diagnostic accuracy of selected language sample measures (LSMs) with Persian-speaking children. A pre-accuracy study followed by phase I and II studies are reported. Twenty-four Persian-speaking children, aged 42 to 54 months, with primary language impairment (PLI) were compared to 27 age-matched children without PLI on a set of measures derived from play-based, conversational language samples. Results showed that correlations between age and LSMs were not statistically significant in either group of children. However, a majority of LSMs differentiated children with and without PLI at the group level (phase I), while three of the measures exhibited good diagnostic accuracy at the level of the individual (phase II). We conclude that general LSMs are promising for distinguishing between children with and without PLI. Persian-specific measures are mainly helpful in identifying children without language impairment while their ability to identify children with PLI is poor.

  6. Comparison of the accuracy of kriging and IDW interpolations in estimating groundwater arsenic concentrations in Texas.

    Science.gov (United States)

    Gong, Gordon; Mattevada, Sravan; O'Bryant, Sid E

    2014-04-01

    Exposure to arsenic causes many diseases. Most Americans in rural areas use groundwater for drinking, which may contain arsenic above the currently allowable level, 10µg/L. It is cost-effective to estimate groundwater arsenic levels based on data from wells with known arsenic concentrations. We compared the accuracy of several commonly used interpolation methods in estimating arsenic concentrations in >8000 wells in Texas by the leave-one-out-cross-validation technique. Correlation coefficient between measured and estimated arsenic levels was greater with inverse distance weighted (IDW) than kriging Gaussian, kriging spherical or cokriging interpolations when analyzing data from wells in the entire Texas (pgroundwater arsenic level depends on both interpolation methods and wells' geographic distributions and characteristics in Texas. Taking well depth and elevation into regression analysis as covariates significantly increases the accuracy in estimating groundwater arsenic level in Texas with IDW in particular. Published by Elsevier Inc.

  7. The accuracy of dynamic attitude propagation

    Science.gov (United States)

    Harvie, E.; Chu, D.; Woodard, M.

    1990-01-01

    Propagating attitude by integrating Euler's equation for rigid body motion has long been suggested for the Earth Radiation Budget Satellite (ERBS) but until now has not been implemented. Because of limited Sun visibility, propagation is necessary for yaw determination. With the deterioration of the gyros, dynamic propagation has become more attractive. Angular rates are derived from integrating Euler's equation with a stepsize of 1 second, using torques computed from telemetered control system data. The environmental torque model was quite basic. It included gravity gradient and unshadowed aerodynamic torques. Knowledge of control torques is critical to the accuracy of dynamic modeling. Due to their coarseness and sparsity, control actuator telemetry were smoothed before integration. The dynamic model was incorporated into existing ERBS attitude determination software. Modeled rates were then used for attitude propagation in the standard ERBS fine-attitude algorithm. In spite of the simplicity of the approach, the dynamically propagated attitude matched the attitude propagated with good gyros well for roll and yaw but diverged up to 3 degrees for pitch because of the very low resolution in pitch momentum wheel telemetry. When control anomalies significantly perturb the nominal attitude, the effect of telemetry granularity is reduced and the dynamically propagated attitudes are accurate on all three axes.

  8. Accuracy of crystal structure error estimates

    International Nuclear Information System (INIS)

    Taylor, R.; Kennard, O.

    1986-01-01

    A statistical analysis of 100 crystal structures retrieved from the Cambridge Structural Database is reported. Each structure has been determined independently by two different research groups. Comparison of the independent results leads to the following conclusions: (a) The e.s.d.'s of non-hydrogen-atom positional parameters are almost invariably too small. Typically, they are underestimated by a factor of 1.4-1.45. (b) The extent to which e.s.d.'s are underestimated varies significantly from structure to structure and from atom to atom within a structure. (c) Errors in the positional parameters of atoms belonging to the same chemical residue tend to be positively correlated. (d) The e.s.d.'s of heavy-atom positions are less reliable than those of light-atom positions. (e) Experimental errors in atomic positional parameters are normally, or approximately normally, distributed. (f) The e.s.d.'s of cell parameters are grossly underestimated, by an average factor of about 5 for cell lengths and 2.5 for cell angles. There is marginal evidence that the accuracy of atomic-coordinate e.s.d.'s also depends on diffractometer geometry, refinement procedure, whether or not the structure has a centre of symmetry, and the degree of precision attained in the structure determination. (orig.)

  9. Accuracy in activation analysis: count rate effects

    International Nuclear Information System (INIS)

    Lindstrom, R.M.; Fleming, R.F.

    1980-01-01

    The accuracy inherent in activation analysis is ultimately limited by the uncertainty of counting statistics. When careful attention is paid to detail, several workers have shown that all systematic errors can be reduced to an insignificant fraction of the total uncertainty, even when the statistical limit is well below one percent. A matter of particular importance is the reduction of errors due to high counting rate. The loss of counts due to random coincidence (pulse pileup) in the amplifier and to digitization time in the ADC may be treated as a series combination of extending and non-extending dead times, respectively. The two effects are experimentally distinct. Live timer circuits in commercial multi-channel analyzers compensate properly for ADC dead time for long-lived sources, but not for pileup. Several satisfactory solutions are available, including pileup rejection and dead time correction circuits, loss-free ADCs, and computed corrections in a calibrated system. These methods are sufficiently reliable and well understood that a decaying source can be measured routinely with acceptably small errors at a dead time as high as 20 percent

  10. Accuracy of Spindle Units with Hydrostatic Bearings

    Directory of Open Access Journals (Sweden)

    Fedorynenko Dmytro

    2016-06-01

    Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

  11. Needle placement accuracy during stereotactic localization mammography

    International Nuclear Information System (INIS)

    Green, D.H.

    2009-01-01

    Aim: To derive a mathematical model to describe the relationship between lesion position in the breast and measurements derived from the stereoradiographs to enable more accurate sampling of a lesion during stereotactic mammographic needle placement. Materials and methods: The affect that registration errors have on the accuracy of needle placement when identifying the lesion on the stereoradiographs was investigated using the mathematical model. Results: The focus-to-film distance of the x-ray tube and the horizontal distance of the lesion from the centre of rotation have little effect on error. Registration errors for lesions lying at a greater perpendicular distance in the breast from the centre of rotation produce smaller localization errors when compared with lesions sited closer. Lesion registration errors during marking of the stereoradiographs are exacerbated by decreasing the angle of x-ray tube swing. Conclusions: When problems are encountered in making an accurate registration of the lesion on the stereoradiographs, consider the following error reducing strategies: (1) employ an approach that places the lesion the maximum distance away from the film cassette; (2) avoid reducing the angle of tube swing; and (3) consider sampling superficial and deep to, as well as at, the location indicated. The possibility of erroneous tissue sampling should be borne in mind when reviewing the pathology report.

  12. Overlay accuracy with respect to device scaling

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee

    2012-03-01

    Overlay metrology performance is usually reported as repeatability, matching between tools or optics aberrations distorting the measurement (Tool induced shift or TIS). Over the last few years, improvement of these metrics by the tool suppliers has been impressive. But, what about accuracy? Using different target types, we have already reported small differences in the mean value as well as fingerprint [1]. These differences make the correctables questionable. Which target is correct and therefore which translation, scaling etc. values should be fed back to the scanner? In this paper we investigate the sources of these differences, using several approaches. First, we measure the response of different targets to offsets programmed in a test vehicle. Second, we check the response of the same overlay targets to overlay errors programmed into the scanner. We compare overlay target designs; what is the contribution of the size of the features that make up the target? We use different overlay measurement techniques; is DBO (Diffraction Based Overlay) more accurate than IBO (Image Based Overlay)? We measure overlay on several stacks; what is the stack contribution to inaccuracy? In conclusion, we offer an explanation for the observed differences and propose a solution to reduce them.

  13. Accuracy and speed feedback: Global and local effects on strategy use

    Science.gov (United States)

    Touron, Dayna R.; Hertzog, Christopher

    2013-01-01

    Background Skill acquisition often involves a shift from an effortful algorithm-based strategy to more fluent memory-based performance. Older adults’ slower strategy transitions can be ascribed to both slowed learning and metacognitive factors. Experimenters often provide feedback on response accuracy; this emphasis may either inadvertently reinforce older adults’ conservatism or might highlight that retrieval is generally quite accurate. RT feedback can lead to more rapid shift to retrieval (Hertzog, Touron, & Hines, 2007). Methods This study parametrically varied trial-by-trial feedback to examine whether strategy shifts in the noun-pair task in younger (M = 19) and older adults (M = 67) were influenced by type of performance feedback: none, trial accuracy, trial RT, or both accuracy and RT. Results Older adults who received accuracy feedback retrieved more often, particularly on difficult rearranged trials, and participants who receive speed feedback performed the scanning strategy more quickly. Age differences were also obtained in local (trial-level) reactivity to task performance, but these were not affected by feedback. Conclusions Accuracy and speed feedback had distinct global (general) influences on task strategies and performance. In particular, it appears that the standard practice of providing trial-by-trial accuracy feedback might facilitate older adults’ use of retrieval strategies in skill acquisition tasks. PMID:24785594

  14. The effect of search term on the quality and accuracy of online information regarding distal radius fractures.

    Science.gov (United States)

    Dy, Christopher J; Taylor, Samuel A; Patel, Ronak M; Kitay, Alison; Roberts, Timothy R; Daluiski, Aaron

    2012-09-01

    Recent emphasis on shared decision making and patient-centered research has increased the importance of patient education and health literacy. The internet is rapidly growing as a source of self-education for patients. However, concern exists over the quality, accuracy, and readability of the information. Our objective was to determine whether the quality, accuracy, and readability of information online about distal radius fractures vary with the search term. This was a prospective evaluation of 3 search engines using 3 different search terms of varying sophistication ("distal radius fracture," "wrist fracture," and "broken wrist"). We evaluated 70 unique Web sites for quality, accuracy, and readability. We used comparative statistics to determine whether the search term affected the quality, accuracy, and readability of the Web sites found. Three orthopedic surgeons independently gauged quality and accuracy of information using a set of predetermined scoring criteria. We evaluated the readability of the Web site using the Fleisch-Kincaid score for reading grade level. There were significant differences in the quality, accuracy, and readability of information found, depending on the search term. We found higher quality and accuracy resulted from the search term "distal radius fracture," particularly compared with Web sites resulting from the term "broken wrist." The reading level was higher than recommended in 65 of the 70 Web sites and was significantly higher when searching with "distal radius fracture" than "wrist fracture" or "broken wrist." There was no correlation between Web site reading level and quality or accuracy. The readability of information about distal radius fractures in most Web sites was higher than the recommended reading level for the general public. The quality and accuracy of the information found significantly varied with the sophistication of the search term used. Physicians, professional societies, and search engines should consider

  15. Liquid level measurement in high level nuclear waste slurries

    International Nuclear Information System (INIS)

    Weeks, G.E.; Heckendorn, F.M.; Postles, R.L.

    1990-01-01

    Accurate liquid level measurement has been a difficult problem to solve for the Defense Waste Processing Facility (DWPF). The nuclear waste sludge tends to plug or degrade most commercially available liquid-level measurement sensors. A liquid-level measurement system that meets demanding accuracy requirements for the DWPF has been developed. The system uses a pneumatic 1:1 pressure repeater as a sensor and a computerized error correction system. 2 figs

  16. Diagnostic accuracy of contemporary multidetector computed tomography (MDCT) for the detection of lumbar disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Notohamiprodjo, S.; Stahl, R.; Braunagel, M.; Kazmierczak, P.M.; Thierfelder, K.M.; Treitl, K.M.; Wirth, S. [University Hospital of Munich, LMU Munich, Institute for Clinical Radiology, Munich (Germany); Notohamiprodjo, M. [University Hospital Tuebingen, Eberhard Karls University Tuebingen, Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2017-08-15

    To evaluate the diagnostic accuracy of multidetector CT (MDCT) for detection of lumbar disc herniation with MRI as standard of reference. Patients with low back pain underwent indicated MDCT (128-row MDCT, helical pitch), 60 patients with iterative reconstruction (IR) and 67 patients with filtered back projection (FBP). Lumbar spine MRI (1.5 T) was performed within 1 month. Signal-to-noise ratios (SNR) of cerebrospinal fluid (CSF), annulus fibrosus (AF) and the spinal cord (SC) were determined for all modalities. Two readers independently rated image quality (IQ), diagnostic confidence and accuracy in the diagnosis of lumbar disc herniation using MRI as standard of reference. Inter-reader correlation was assessed with weighted κ. Sensitivity, specificity, precision and accuracy of MDCT for disc protrusion were 98.8%, 96.5%, 97.1%, 97.8% (disc level), 97.7%, 92.9%, 98.6%, 96.9% (patient level). SNR of IR was significantly higher than FBP. IQ was significantly better in IR owing to visually reduced noise and improved delineation of the discs. κ (>0.90) was excellent for both algorithms. MDCT of the lumbar spine yields high diagnostic accuracy for detection of lumbar disc herniation. IR improves image quality so that the provided diagnostic accuracy is principally equivalent to MRI. (orig.)

  17. Bounds on achievable accuracy in analog optical linear-algebra processors

    Science.gov (United States)

    Batsell, Stephen G.; Walkup, John F.; Krile, Thomas F.

    1990-07-01

    Upper arid lower bounds on the number of bits of accuracy achievable are determined by applying a seconth-ortler statistical model to the linear algebra processor. The use of bounds was found necessary due to the strong signal-dependence of the noise at the output of the optical linear algebra processor (OLAP). 1 1. ACCURACY BOUNDS One of the limiting factors in applying OLAPs to real world problems has been the poor achievable accuracy of these processors. Little previous research has been done on determining noise sources from a systems perspective which would include noise generated in the multiplication ard addition operations spatial variations across arrays and crosstalk. We have previously examined these noise sources and determined a general model for the output noise mean and variance. The model demonstrates a strony signaldependency in the noise at the output of the processor which has been confirmed by our experiments. 1 We define accuracy similar to its definition for an analog signal input to an analog-to-digital (ND) converter. The number of bits of accuracy achievable is related to the log (base 2) of the number of separable levels at the P/D converter output. The number of separable levels is fouri by dividing the dynamic range by m times the standard deviation of the signal a. 2 Here m determines the error rate in the P/D conversion. The dynamic range can be expressed as the

  18. Analysis of accuracy in photogrammetric roughness measurements

    Science.gov (United States)

    Olkowicz, Marcin; Dąbrowski, Marcin; Pluymakers, Anne

    2017-04-01

    Regarding permeability, one of the most important features of shale gas reservoirs is the effective aperture of cracks opened during hydraulic fracturing, both propped and unpropped. In a propped fracture, the aperture is controlled mostly by proppant size and its embedment, and fracture surface roughness only has a minor influence. In contrast, in an unpropped fracture aperture is controlled by the fracture roughness and the wall displacement. To measure fracture surface roughness, we have used the photogrammetric method since it is time- and cost-efficient. To estimate the accuracy of this method we compare the photogrammetric measurements with reference measurements taken with a White Light Interferometer (WLI). Our photogrammetric setup is based on high resolution 50 Mpx camera combined with a focus stacking technique. The first step for photogrammetric measurements is to determine the optimal camera positions and lighting. We compare multiple scans of one sample, taken with different settings of lighting and camera positions, with the reference WLI measurement. The second step is to perform measurements of all studied fractures with the parameters that produced the best results in the first step. To compare photogrammetric and WLI measurements we regrid both data sets onto a regular 10 μm grid and determined the best fit, followed by a calculation of the difference between the measurements. The first results of the comparison show that for 90 % of measured points the absolute vertical distance between WLI and photogrammetry is less than 10 μm, while the mean absolute vertical distance is 5 μm. This proves that our setup can be used for fracture roughness measurements in shales.

  19. Complete-arch accuracy of intraoral scanners.

    Science.gov (United States)

    Treesh, Joshua C; Liacouras, Peter C; Taft, Robert M; Brooks, Daniel I; Raiciulescu, Sorana; Ellert, Daniel O; Grant, Gerald T; Ye, Ling

    2018-04-30

    Intraoral scanners have shown varied results in complete-arch applications. The purpose of this in vitro study was to evaluate the complete-arch accuracy of 4 intraoral scanners based on trueness and precision measurements compared with a known reference (trueness) and with each other (precision). Four intraoral scanners were evaluated: CEREC Bluecam, CEREC Omnicam, TRIOS Color, and Carestream CS 3500. A complete-arch reference cast was created and printed using a 3-dimensional dental cast printer with photopolymer resin. The reference cast was digitized using a laboratory-based white light 3-dimensional scanner. The printed reference cast was scanned 10 times with each intraoral scanner. The digital standard tessellation language (STL) files from each scanner were then registered to the reference file and compared with differences in trueness and precision using a 3-dimensional modeling software. Additionally, scanning time was recorded for each scan performed. The Wilcoxon signed rank, Kruskal-Wallis, and Dunn tests were used to detect differences for trueness, precision, and scanning time (α=.05). Carestream CS 3500 had the lowest overall trueness and precision compared with Bluecam and TRIOS Color. The fourth scanner, Omnicam, had intermediate trueness and precision. All of the scanners tended to underestimate the size of the reference file, with exception of the Carestream CS 3500, which was more variable. Based on visual inspection of the color rendering of signed differences, the greatest amount of error tended to be in the posterior aspects of the arch, with local errors exceeding 100 μm for all scans. The single capture scanner Carestream CS 3500 had the overall longest scan times and was significantly slower than the continuous capture scanners TRIOS Color and Omnicam. Significant differences in both trueness and precision were found among the scanners. Scan times of the continuous capture scanners were faster than the single capture scanners

  20. Does Language Influence the Accuracy of Judgments of Stuttering in Children?

    Science.gov (United States)

    Einarsdottir, Johanna; Ingham, Roger J.

    2009-01-01

    Purpose: To determine whether stuttering judgment accuracy is influenced by familiarity with the stuttering speaker's language. Method: Audiovisual 7-min speech samples from nine 3- to 5-year-olds were used. Icelandic children who stutter (CWS), preselected for different levels of stuttering, were subdivided into 5-s intervals. Ten experienced…

  1. Cued Speech Transliteration: Effects of Accuracy and Lag Time on Message Intelligibility

    Science.gov (United States)

    Krause, Jean C.; Lopez, Katherine A.

    2017-01-01

    This paper is the second in a series concerned with the level of access afforded to students who use educational interpreters. The first paper (Krause & Tessler, 2016) focused on factors affecting accuracy of messages produced by Cued Speech (CS) transliterators (expression). In this study, factors affecting intelligibility (reception by deaf…

  2. MEASURING ACCURACY AND COMPLEXITY OF AN L2 LEARNER’S ORAL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Teguh Khaerudin

    2015-03-01

    Full Text Available This paper aims at examining the influence of different tasks on the degree of task performance in a second language learner’s oral production. The underlying assumption is that among the three aspects of language performance in L2, i.e. fluency, accuracy, and complexity, learners may prioritize only one of them (Ellis & Barkhuizen, 2005, p. 150 and that their decision to prioritize one particular area of language performance may be determined by the characteristics of the task given to the learners (Skehan & Foster, 1997. Having a written record of an oral production, the writer focuses this study on determining the degree of complexity and accuracy, and analyzing whether the different tasks change the level of learner’s oral performance. The results show that learner’s accuracy from both tasks remains in the same level. However, both task conditions, which do not allow speech plan, result in no improvement in accuracy level and a minor improvement in the complexity level.

  3. Evaluation of the diagnostic accuracy of the HemoCue device for ...

    African Journals Online (AJOL)

    To assess the validity of the HemoCue in relation to the gold-standard laboratory method. Methods. A cross-sectional study of children aged 6 - 8 years, analysing the diagnostic accuracy of the HemoCue in determining Hb levels in venous blood. Agreement between the HemoCue and laboratory techniques was evaluated ...

  4. Multiple motives and persuasive communication : Creative elaboration as a result of impression motivation and accuracy motivation

    NARCIS (Netherlands)

    Nienhuis, AE; Manstead, ASR; Spears, R

    The authors examined the influence of impression motivation (Experiments 1 and 2) and the combined effects of accuracy motivation and impression motivation (Experiment 3) on the elaboration of persuasive messages as reflected in attitude change and cognitive responses. Intermediate levels of

  5. Predictive Validity and Accuracy of Oral Reading Fluency for English Learners

    Science.gov (United States)

    Vanderwood, Michael L.; Tung, Catherine Y.; Checca, C. Jason

    2014-01-01

    The predictive validity and accuracy of an oral reading fluency (ORF) measure for a statewide assessment in English language arts was examined for second-grade native English speakers (NESs) and English learners (ELs) with varying levels of English proficiency. In addition to comparing ELs with native English speakers, the impact of English…

  6. The Push for More Challenging Texts: An Analysis of Early Readers' Rate, Accuracy, and Comprehension

    Science.gov (United States)

    Amendum, Steven J.; Conradi, Kristin; Liebfreund, Meghan D.

    2016-01-01

    The purpose of the study was to examine the relationship between the challenge level of text and early readers' reading comprehension. This relationship was also examined with consideration to students' word recognition accuracy and reading rate. Participants included 636 students, in Grades 1-3, in a southeastern state. Results suggest that…

  7. Assessing sensor accuracy for non-adjunct use of continuous glucose monitoring.

    Science.gov (United States)

    Kovatchev, Boris P; Patek, Stephen D; Ortiz, Edward Andrew; Breton, Marc D

    2015-03-01

    The level of continuous glucose monitoring (CGM) accuracy needed for insulin dosing using sensor values (i.e., the level of accuracy permitting non-adjunct CGM use) is a topic of ongoing debate. Assessment of this level in clinical experiments is virtually impossible because the magnitude of CGM errors cannot be manipulated and related prospectively to clinical outcomes. A combination of archival data (parallel CGM, insulin pump, self-monitoring of blood glucose [SMBG] records, and meals for 56 pump users with type 1 diabetes) and in silico experiments was used to "replay" real-life treatment scenarios and relate sensor error to glycemic outcomes. Nominal blood glucose (BG) traces were extracted using a mathematical model, yielding 2,082 BG segments each initiated by insulin bolus and confirmed by SMBG. These segments were replayed at seven sensor accuracy levels (mean absolute relative differences [MARDs] of 3-22%) testing six scenarios: insulin dosing using sensor values, threshold, and predictive alarms, each without or with considering CGM trend arrows. In all six scenarios, the occurrence of hypoglycemia (frequency of BG levels ≤50 mg/dL and BG levels ≤39 mg/dL) increased with sensor error, displaying an abrupt slope change at MARD =10%. Similarly, hyperglycemia (frequency of BG levels ≥250 mg/dL and BG levels ≥400 mg/dL) increased and displayed an abrupt slope change at MARD=10%. When added to insulin dosing decisions, information from CGM trend arrows, threshold, and predictive alarms resulted in improvement in average glycemia by 1.86, 8.17, and 8.88 mg/dL, respectively. Using CGM for insulin dosing decisions is feasible below a certain level of sensor error, estimated in silico at MARD=10%. In our experiments, further accuracy improvement did not contribute substantively to better glycemic outcomes.

  8. Quantitative accuracy assessment of thermalhydraulic code predictions with SARBM

    International Nuclear Information System (INIS)

    Prosek, A.

    2001-01-01

    In recent years, the nuclear reactor industry has focused significant attention on nuclear reactor systems code accuracy and uncertainty issues. A few methods suitable to quantify code accuracy of thermalhydraulic code calculations were proposed and applied in the past. In this study a Stochastic Approximation Ratio Based Method (SARBM) was adapted and proposed for accuracy quantification. The objective of the study was to qualify the SARBM. The study compare the accuracy obtained by SARBM with the results obtained by widely used Fast Fourier Transform Based Method (FFTBM). The methods were applied to RELAP5/MOD3.2 code calculations of various BETHSY experiments. The obtained results showed that the SARBM was able to satisfactorily predict the accuracy of the calculated trends when visually comparing plots and comparing the results with the qualified FFTBM. The analysis also showed that the new figure-of-merit called accuracy factor (AF) is more convenient than stochastic approximation ratio for combining single variable accuracy's into total accuracy. The accuracy results obtained for the selected tests suggest that the acceptability factors for the SAR method were reasonably defined. The results also indicate that AF is a useful quantitative measure of accuracy.(author)

  9. Experimental assessment of the accuracy of genomic selection in sugarcane.

    Science.gov (United States)

    Gouy, M; Rousselle, Y; Bastianelli, D; Lecomte, P; Bonnal, L; Roques, D; Efile, J-C; Rocher, S; Daugrois, J; Toubi, L; Nabeneza, S; Hervouet, C; Telismart, H; Denis, M; Thong-Chane, A; Glaszmann, J C; Hoarau, J-Y; Nibouche, S; Costet, L

    2013-10-01

    Sugarcane cultivars are interspecific hybrids with an aneuploid, highly heterozygous polyploid genome. The complexity of the sugarcane genome is the main obstacle to the use of marker-assisted selection in sugarcane breeding. Given the promising results of recent studies of plant genomic selection, we explored the feasibility of genomic selection in this complex polyploid crop. Genetic values were predicted in two independent panels, each composed of 167 accessions representing sugarcane genetic diversity worldwide. Accessions were genotyped with 1,499 DArT markers. One panel was phenotyped in Reunion Island and the other in Guadeloupe. Ten traits concerning sugar and bagasse contents, digestibility and composition of the bagasse, plant morphology, and disease resistance were used. We used four statistical predictive models: bayesian LASSO, ridge regression, reproducing kernel Hilbert space, and partial least square regression. The accuracy of the predictions was assessed through the correlation between observed and predicted genetic values by cross validation within each panel and between the two panels. We observed equivalent accuracy among the four predictive models for a given trait, and marked differences were observed among traits. Depending on the trait concerned, within-panel cross validation yielded median correlations ranging from 0.29 to 0.62 in the Reunion Island panel and from 0.11 to 0.5 in the Guadeloupe panel. Cross validation between panels yielded correlations ranging from 0.13 for smut resistance to 0.55 for brix. This level of correlations is promising for future implementations. Our results provide the first validation of genomic selection in sugarcane.

  10. The ripple electromagnetic calculation: accuracy demand and possible responses

    International Nuclear Information System (INIS)

    Cocilovo, V.; Ramogida, G.; Formisano, A.; Martone, R.; Portone, A.; Roccella, M.; Roccella, R.

    2006-01-01

    Due to a number of causes (the finite number of toroidal field coils or the presence of concentrate blocks of magnetic materials, as the neutral beam shielding) the actual magnetic configuration in a Tokamak differs from the desired one. For example, a ripple is added to the ideal axisymmetric toroidal field, impacting the equilibrium and stability of the plasma column; as a further example the magnetic field out of plasma affects the operation of a number of critical components, included the diagnostic system and the neutral beam. Therefore the actual magnetic field has to be suitably calculated and his shape controlled within the required limits. Due to the complexity of its design, the problem is quite critical for the ITER project. In this paper the problem is discussed both from mathematical and numerical point of view. In particular, a complete formulation is proposed, taking into account both the presence of the non linear magnetic materials and the fully 3D geometry. Then the quality level requirements are discussed, included the accuracy of calculations and the spatial resolution. As a consequence, the numerical tools able to fulfil the quality needs while requiring reasonable computer burden are considered. In particular possible tools based on numerical FEM scheme are considered; in addition, in spite of the presence of non linear materials, the practical possibility to use Biot-Savart based approaches, as cross check tools, is also discussed. The paper also analyses the possible geometrical simplifications of the geometry able to make possible the actual calculation while guarantying the required accuracy. Finally the characteristics required for a correction system able to effectively counteract the magnetic field degradation are presented. Of course a number of examples will be also reported and commented. (author)

  11. Accuracy of quantitative visual soil assessment

    Science.gov (United States)

    van Leeuwen, Maricke; Heuvelink, Gerard; Stoorvogel, Jetse; Wallinga, Jakob; de Boer, Imke; van Dam, Jos; van Essen, Everhard; Moolenaar, Simon; Verhoeven, Frank; Stoof, Cathelijne

    2016-04-01

    Visual soil assessment (VSA) is a method to assess soil quality visually, when standing in the field. VSA is increasingly used by farmers, farm organisations and companies, because it is rapid and cost-effective, and because looking at soil provides understanding about soil functioning. Often VSA is regarded as subjective, so there is a need to verify VSA. Also, many VSAs have not been fine-tuned for contrasting soil types. This could lead to wrong interpretation of soil quality and soil functioning when contrasting sites are compared to each other. We wanted to assess accuracy of VSA, while taking into account soil type. The first objective was to test whether quantitative visual field observations, which form the basis in many VSAs, could be validated with standardized field or laboratory measurements. The second objective was to assess whether quantitative visual field observations are reproducible, when used by observers with contrasting backgrounds. For the validation study, we made quantitative visual observations at 26 cattle farms. Farms were located at sand, clay and peat soils in the North Friesian Woodlands, the Netherlands. Quantitative visual observations evaluated were grass cover, number of biopores, number of roots, soil colour, soil structure, number of earthworms, number of gley mottles and soil compaction. Linear regression analysis showed that four out of eight quantitative visual observations could be well validated with standardized field or laboratory measurements. The following quantitative visual observations correlated well with standardized field or laboratory measurements: grass cover with classified images of surface cover; number of roots with root dry weight; amount of large structure elements with mean weight diameter; and soil colour with soil organic matter content. Correlation coefficients were greater than 0.3, from which half of the correlations were significant. For the reproducibility study, a group of 9 soil scientists and 7

  12. Improving treatment planning accuracy through multimodality imaging

    International Nuclear Information System (INIS)

    Sailer, Scott L.; Rosenman, Julian G.; Soltys, Mitchel; Cullip, Tim J.; Chen, Jun

    1996-01-01

    the patient's initial fields and boost, respectively. Case illustrations are shown. Conclusions: We have successfully integrated multimodality imaging into our treatment-planning system, and its routine use is increasing. Multimodality imaging holds out the promise of improving treatment planning accuracy and, thus, takes maximum advantage of three dimensional treatment planning systems.

  13. Sampling Molecular Conformers in Solution with Quantum Mechanical Accuracy at a Nearly Molecular-Mechanics Cost.

    Science.gov (United States)

    Rosa, Marta; Micciarelli, Marco; Laio, Alessandro; Baroni, Stefano

    2016-09-13

    We introduce a method to evaluate the relative populations of different conformers of molecular species in solution, aiming at quantum mechanical accuracy, while keeping the computational cost at a nearly molecular-mechanics level. This goal is achieved by combining long classical molecular-dynamics simulations to sample the free-energy landscape of the system, advanced clustering techniques to identify the most relevant conformers, and thermodynamic perturbation theory to correct the resulting populations, using quantum-mechanical energies from density functional theory. A quantitative criterion for assessing the accuracy thus achieved is proposed. The resulting methodology is demonstrated in the specific case of cyanin (cyanidin-3-glucoside) in water solution.

  14. Plasma Arc Cutting Dimensional Accuracy Optimization employing the Parameter Design approach

    Directory of Open Access Journals (Sweden)

    Kechagias John

    2017-01-01

    Full Text Available Plasma Arc Cutting (PAC is a thermal manufacturing process used for metal plates cutting. This work experimentally investigates the influence of process parameters onto the dimensional accuracy performance of the plasma arc cutting process. The cutting parameters studied were cutting speed (mm/min, torch standoff distance (mm, and arc voltage (volts. Linear dimensions of a rectangular workpiece were measured after PAC cutting following the full factorial design experimental approach. For each one of the three process parameters, three parameter levels were used. Analysis of means (ANOM and analysis of variances (ANOVA were performed in order for the effect of each parameter on the leaner dimensional accuracy to be assessed.

  15. Dynamic Modeling Accuracy Dependence on Errors in Sensor Measurements, Mass Properties, and Aircraft Geometry

    Science.gov (United States)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    A nonlinear simulation of the NASA Generic Transport Model was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of dynamic models identified from flight data. Measurements from a typical system identification maneuver were systematically and progressively deteriorated and then used to estimate stability and control derivatives within a Monte Carlo analysis. Based on the results, recommendations were provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using other flight conditions, parameter estimation methods, and a full-scale F-16 nonlinear aircraft simulation were compared with these recommendations.

  16. Free and total testosterone levels in field males of Octodon degus (Rodentia, Octodontidae: accuracy of the hormonal regulation of behavior Niveles de testosterona libre y totales en machos silvestres de Octodon degus (Rodentia, Octodontidae: exactitud de la regulación hormonal del comportamiento

    Directory of Open Access Journals (Sweden)

    MAURICIO SOTO- GAMBOA

    2005-06-01

    Full Text Available Animals exhibit continuous seasonal changes in physiological, morphological and behavioral traits associated to their natural annual cycles. One of the most important changes in the organism occurs at the initiation of breeding season. In males these changes include activation of spermatogenesis, enhance of sexual secondary characters and an increase of aggressiveness. All of theses changes are basically regulated by testosterone, but the physiological basis of this testosterone regulation and the effective hormone proportion that acts in target tissues are unknown. In this work I evaluated the relationship between total testosterone, free testosterone associated to aggressive behavior in wild males of Octodon degus. I compared hormonal levels and aggressive behavior during pre, middle and post breeding periods. Results showed that behavioral aggressiveness was correlated with both total and free testosterone in June, during the beginning of breeding season, but not at other times. Results also indicated a lack of relationship between free and total testosterone in most of breeding period. I discuss the importance of this behavior-hormonal regulation (determined by free testosterone and the physiological importance of this mechanism to the organismLos animales presentan variaciones estacionales continuas que incluyen cambios fisiológicos, morfológicos y conductuales, asociados al ciclo anual. Estos cambios generalmente están activados por factores endógenos o exógenos, pero son regulados por el sistema endocrino de organismo. Uno de los cambios más importantes ocurre en el inicio del periodo reproductivo. Durante este periodo los machos presentan cambios asociados a la producción de esperatozoides, exacerbación de caracteres sexuales secundarios y un aumento de la agresividad. Todos estos cambios son regulados en parte por los niveles de testosterona, sin embargo, los mecanismos fisiológicos de esta regulación son desconocidos. En este

  17. Speed Accuracy Tradeoffs in Human Speech Production

    Science.gov (United States)

    2017-05-01

    Massachusetts, USA Classification: Biological Sciences, Psychological and Cognitive Sciences 1Corresponding Author: Adam.Lammert@LL.mit.edu SPEED... psychology , 67 (2), 103. Fitts, P. M., & Radford, B. K. (1966). Information capacity of discrete motor responses under different cognitive sets. Journal...constriction degree and location, as in Articulatory Phonology (Browman & Goldstein , 1992). These high-level spaces are the natural spaces in which to define

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

    International Nuclear Information System (INIS)

    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

    2012-01-01

    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° (standard deviation [SD] 0.06°), 0.02° (SD 0.07°), and 0.06° (SD 0.14°) for longitudinal, lateral, and vertical rotations, respectively. The average positioning accuracy was 0.06° (SD 0.04°), 0.08° (SD 0.06°), and 0.08° (SD 0.07°) 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 frameless technique showed comparable accuracy to the frame-based approach.

  19. LEARNER AUTONOMY ON ESSAY WRITING ACCURACY

    Directory of Open Access Journals (Sweden)

    Mohammad Hafidz

    2018-01-01

    Full Text Available Abstract: Learner autonomy on writing is independently teaching and learning that keeps students’ control to explore their knowledge and experiences in written language, find out and evaluate their errors based on the conceptual courses to make accurately simple essay. The aim was to know the effectiveness of the learner autonomy on writing accuracy. This quantitative research conducted in one group pretest and posttest design. The number of samples was 21 students in Bangkalan. The instrument were tests to gain students’ writing score before and after treatment. Researcher statistically analyzed the data using SPSS 23 version by running a Paired Samples Test. The result shown the means of pretes score was 66,83 and posttest score was 74,57, Paired Samples Correlations was 0,614 (strong correlation. Significance was 0,005, it means that  a (0,05 is higher than r value (0,005 with high variance of mean value (14,091. As a result, the hypothesis (H1­ was received that learner autonomy contributed effectively to learners’ in organizing own ideas (Ene, 2006 such as making a topic  map becomes some explanable sub-topics, writing down main and supporting idea, clustering some objects, editing next and learners  absolutely accumulate some selected vocabularies inappropriate topics  (Chengping W, 2008. Keyword: Learner Autonomy, Learning process, outcomes Absrak: Pembelajaran otonomi  adalah pembelajaran mandiri yang mengontrol mahasiswa untuk menyampaikan gagasan dan pengalamannya, mencatat dan mengevaluasi kesalahan yang terjadi dalam penulisan esai sederhana berdasarkan pembelajaran yang tersetruktur. Tujuan adalah untuk mengetahui efektifitas pembelajaran otonomi terhadap akurasi tulisan secara statistik. Penelitian ini dilakukan dengan menggunakan desain tes awal dan akhir. Jumlah sampel terdiri dari 21 siswa di Bangkalan. Isntrumen yang digunakan adalah tes untuk mengetahui hasil nilai mahasiswa sebelum dan sesudah melakukan

  20. Positioning accuracy of the neurotron 1000

    International Nuclear Information System (INIS)

    Cox, Richard S.; Murphy, Martin J.

    1995-01-01

    Purpose: The Neurotron 1000 is a novel treatment machine under development for frameless stereotaxic radiosurgery that consists of a compact X-band accelerator mounted on a robotic arm. The therapy beam is guided to the lesion by an imaging system, which includes two diagnostic x-ray cameras that view the patient during treatment. Patient position and motion are measured by the imaging system and appropriate corrections are communicated in real time to the robotic arm for beam targeting and motion tracking. The three tests reported here measured the pointing accuracy of the therapy beam and the present capability of the imaging guidance system. Materials and Methods: 1) The positioning and pointing test measured the ability of the robotic arm to direct the beam through a test isocenter from arbitrary arm positions. The test isocenter was marked by a small light-sensitive crystal and the beam axis was simulated by a laser. The robot was directed to move the linac to a variety of positions, aiming the laser at the crystal detector from each position. The distance of the beam axis from the crystal was measured for each robot position. 2) The imaging-guidance system was tested by moving phantoms about in the field of view of the camera by precisely known displacements and comparing the guidance system's measurement of the phantom position with the its actual position. 3) The system's overall pointing and tracking capability was measured by an end-to-end test using a dosimetric phantom containing radiochromic film. The phantom was imaged by CT to locate the center of the cubical film package. A set of isocentric robotic paths was calculated to produce a spherical dose distribution at the center of the film package. The phantom with the film was then irradiated by the therapy beam as the robot executed the path, with the imaging system providing the beam targeting directions. Results: 1) The positioning and pointing test was performed for paths consisting of spirals and

  1. EVALUATION OF RELATIVE GEOMETRIC ACCURACY OF TERRASAR-X BY PIXEL MATCHING METHODOLOGY

    Directory of Open Access Journals (Sweden)

    T. Nonaka

    2016-06-01

    Full Text Available Recently, high-resolution commercial SAR satellites with several meters of resolutions are widely utilized for various applications and disaster monitoring is one of the commonly applied areas. The information about the flooding situation and ground displacement was rapidly announced to the public after the Great East Japan Earthquake 2011. One of the studies reported the displacement in Tohoku region by the pixel matching methodology using both pre- and post- event TerraSAR-X data, and the validated accuracy was about 30 cm at the GEONET reference points. In order to discuss the spatial distribution of the displacement, we need to evaluate the relative accuracy of the displacement in addition to the absolute accuracy. In the previous studies, our study team evaluated the absolute 2D geo-location accuracy of the TerraSAR-X ortho-rectified EEC product for both flat and mountain areas. Therefore, the purpose of the current study was to evaluate the spatial and temporal relative geo-location accuracies of the product by considering the displacement of the fixed point as the relative geo-location accuracy. Firstly, by utilizing TerraSAR-X StripMap dataset, the pixel matching method for estimating the displacement with sub-pixel level was developed. Secondly, the validity of the method was confirmed by comparing with GEONET data. We confirmed that the accuracy of the displacement for X and Y direction was in agreement with the previous studies. Subsequently, the methodology was applied to 20 pairs of data set for areas of Tokyo Ota-ku and Kawasaki-shi, and the displacement of each pair was evaluated. It was revealed that the time series displacement rate had the seasonal trend and seemed to be related to atmospheric delay.

  2. Evaluation of Relative Geometric Accuracy of Terrasar-X by Pixel Matching Methodology

    Science.gov (United States)

    Nonaka, T.; Asaka, T.; Iwashita, K.

    2016-06-01

    Recently, high-resolution commercial SAR satellites with several meters of resolutions are widely utilized for various applications and disaster monitoring is one of the commonly applied areas. The information about the flooding situation and ground displacement was rapidly announced to the public after the Great East Japan Earthquake 2011. One of the studies reported the displacement in Tohoku region by the pixel matching methodology using both pre- and post- event TerraSAR-X data, and the validated accuracy was about 30 cm at the GEONET reference points. In order to discuss the spatial distribution of the displacement, we need to evaluate the relative accuracy of the displacement in addition to the absolute accuracy. In the previous studies, our study team evaluated the absolute 2D geo-location accuracy of the TerraSAR-X ortho-rectified EEC product for both flat and mountain areas. Therefore, the purpose of the current study was to evaluate the spatial and temporal relative geo-location accuracies of the product by considering the displacement of the fixed point as the relative geo-location accuracy. Firstly, by utilizing TerraSAR-X StripMap dataset, the pixel matching method for estimating the displacement with sub-pixel level was developed. Secondly, the validity of the method was confirmed by comparing with GEONET data. We confirmed that the accuracy of the displacement for X and Y direction was in agreement with the previous studies. Subsequently, the methodology was applied to 20 pairs of data set for areas of Tokyo Ota-ku and Kawasaki-shi, and the displacement of each pair was evaluated. It was revealed that the time series displacement rate had the seasonal trend and seemed to be related to atmospheric delay.

  3. The Dependence of Cloud Property Trend Detection on Absolute Calibration Accuracy of Passive Satellite Sensors

    Science.gov (United States)

    Shea, Y.; Wielicki, B. A.; Sun-Mack, S.; Minnis, P.; Zelinka, M. D.

    2016-12-01

    Detecting trends in climate variables on global, decadal scales requires highly accurate, stable measurements and retrieval algorithms. Trend uncertainty depends on its magnitude, natural variability, and instrument and retrieval algorithm accuracy and stability. We applied a climate accuracy framework to quantify the impact of absolute calibration on cloud property trend uncertainty. The cloud properties studied were cloud fraction, effective temperature, optical thickness, and effective radius retrieved using the Clouds and the Earth's Radiant Energy System (CERES) Cloud Property Retrieval System, which uses Moderate-resolution Imaging Spectroradiometer measurements (MODIS). Modeling experiments from the fifth phase of the Climate Model Intercomparison Project (CMIP5) agree that net cloud feedback is likely positive but disagree regarding its magnitude, mainly due to uncertainty in shortwave cloud feedback. With the climate accuracy framework we determined the time to detect trends for instruments with various calibration accuracies. We estimated a relationship between cloud property trend uncertainty, cloud feedback, and Equilibrium Climate Sensitivity and also between effective radius trend uncertainty and aerosol indirect effect trends. The direct relationship between instrument accuracy requirements and climate model output provides the level of instrument absolute accuracy needed to reduce climate model projection uncertainty. Different cloud types have varied radiative impacts on the climate system depending on several attributes, such as their thermodynamic phase, altitude, and optical thickness. Therefore, we also conducted these studies by cloud types for a clearer understanding of instrument accuracy requirements needed to detect changes in their cloud properties. Combining this information with the radiative impact of different cloud types helps to prioritize among requirements for future satellite sensors and understanding the climate detection

  4. Thermal ionization mass spectrometry (TIMS) of actinides: Pushing the limits of accuracy and detection

    Energy Technology Data Exchange (ETDEWEB)

    Buerger, Stefan; Boulyga, Sergei; Cunningham, Alan; Klose, Dilani; Koepf, Andreas; Poths, Jane [Safeguards Analytical Laboratory, International Atomic Energy Agency, Vienna (Austria); Richter, Stephan [Institute for Reference Materials and Measurements, JRC-EU, Geel (Belgium)

    2010-07-01

    New method developments in multi-collector thermal ionization mass spectrometry (MC-TIMS) for actinide isotope ratio analysis to improve accuracy and limits of detection will be presented. With respect to limits of detection, results on improving work function using various carbon additives will be reviewed and presented as well as developments in cavity ion source (as compared to standard flat ribbon filament ion source) for femto- and attogram levels of uranium, plutonium, and americium. With respect to accuracy, results on isotope ratio measurements of isotopes of uranium (relative accuracy of 0.3% to 0.01%) are presented with an example being U-234-Th-230 age-dating (NBL CRM 112-A). In this context, the importance of traceability (to the S.I. units) and the use of (certified) reference materials are emphasized. The focus of this presentation is on applications to nuclear safeguards / forensics.

  5. Correlation between the model accuracy and model-based SOC estimation

    International Nuclear Information System (INIS)

    Wang, Qianqian; Wang, Jiao; Zhao, Pengju; Kang, Jianqiang; Yan, Few; Du, Changqing

    2017-01-01

    State-of-charge (SOC) estimation is a core technology for battery management systems. Considerable progress has been achieved in the study of SOC estimation algorithms, especially the algorithm on the basis of Kalman filter to meet the increasing demand of model-based battery management systems. The Kalman filter weakens the influence of white noise and initial error during SOC estimation but cannot eliminate the existing error of the battery model itself. As such, the accuracy of SOC estimation is directly related to the accuracy of the battery model. Thus far, the quantitative relationship between model accuracy and model-based SOC estimation remains unknown. This study summarizes three equivalent circuit lithium-ion battery models, namely, Thevenin, PNGV, and DP models. The model parameters are identified through hybrid pulse power characterization test. The three models are evaluated, and SOC estimation conducted by EKF-Ah method under three operating conditions are quantitatively studied. The regression and correlation of the standard deviation and normalized RMSE are studied and compared between the model error and the SOC estimation error. These parameters exhibit a strong linear relationship. Results indicate that the model accuracy affects the SOC estimation accuracy mainly in two ways: dispersion of the frequency distribution of the error and the overall level of the error. On the basis of the relationship between model error and SOC estimation error, our study provides a strategy for selecting a suitable cell model to meet the requirements of SOC precision using Kalman filter.

  6. Effect of walking speed and placement position interactions in determining the accuracy of various newer pedometers

    Directory of Open Access Journals (Sweden)

    Wonil Park

    2014-06-01

    Full Text Available Older types of pedometers had varied levels of accuracy, which ranged from 0% to 45%. In addition, to obtain accurate results, it was also necessary to position them in a certain way. By contrast, newer models can be placed anywhere on the body; however, their accuracy is unknown when they are placed at different body sites. We determined the accuracy of various newer pedometers under controlled laboratory and free walking conditions. A total of 40 participants, who varied widely in age and body mass index, were recruited for the study. The numbers of steps recorded using five different pedometers placed at the waist, the chest, in a pocket, and on an armband were compared against those counted with a hand tally counter. With the exception of one, all the pedometers were accurate at moderate walking speeds, irrespective of their placement on the body. However, the accuracy tended to decrease at slower and faster walking speeds, especially when the pedometers were worn in the pockets or kept in the purse (p < 0.05. In conclusion, most pedometers examined were accurate when they were placed at the waist, chest, and armband irrespective of the walking speed or terrain. However, some pedometers had reduced accuracy when they were kept in a pocket or placed in a purse, especially at a slower and faster walking speeds.

  7. THE EFFECTS OF APPROACH ANGLE ON PENALTY KICKING ACCURACY AND KICK KINEMATICS WITH RECREATIONAL SOCCER PLAYERS

    Directory of Open Access Journals (Sweden)

    Joanna Scurr

    2009-06-01

    Full Text Available Kicking accuracy is an important component of successful penalty kicks, which may be influenced by the approach angle. The purpose of this study was to examine the effects of approach angle on kicking accuracy and three-dimensional kinematics of penalty kicks. Seven male amateur recreational soccer players aged (mean ± s 26 ± 3 years, body mass 74.0 ± 6.8 kg, stature 1.74 ± 0.06 m, who were right foot dominant, kicked penalties at a 0.6 x 0.6 m target in a full size goal from their self-selected approach angle, 30º, 45º and 60º (direction of the kick was 0º. Kicking accuracy and three-dimensional kinematics were recorded. Results revealed that there was no significant difference in kicking accuracy (p = 0.27 or ball velocity (p = 0.59 between the approach angles. Pelvic rotation was significantly greater under the 45º and the 60º approach angles than during the self-selected approach angle (p < 0.05. Thigh abduction of the kicking leg at impact using the 60º approach angle was significantly greater than during the self- selected approach (p = 0.01 and the 30º approach (p = 0.04. It was concluded that altering an individual's self-selected approach angle at recreational level did not improve kicking accuracy or ball velocity, despite altering aspects of underlying technique.

  8. Accuracy of flash glucose monitoring and continuous glucose monitoring technologies: Implications for clinical practice.

    Science.gov (United States)

    Ajjan, Ramzi A; Cummings, Michael H; Jennings, Peter; Leelarathna, Lalantha; Rayman, Gerry; Wilmot, Emma G

    2018-02-01

    Continuous glucose monitoring and flash glucose monitoring technologies measure glucose in the interstitial fluid and are increasingly used in diabetes care. Their accuracy, key to effective glycaemic management, is usually measured using the mean absolute relative difference of the interstitial fluid sensor compared to reference blood glucose readings. However, mean absolute relative difference is not standardised and has limitations. This review aims to provide a consensus opinion on assessing accuracy of interstitial fluid glucose sensing technologies. Mean absolute relative difference is influenced by glucose distribution and rate of change; hence, we express caution on the reliability of comparing mean absolute relative difference data from different study systems and conditions. We also review the pitfalls associated with mean absolute relative difference at different glucose levels and explore additional ways of assessing accuracy of interstitial fluid devices. Importantly, much data indicate that current practice of assessing accuracy of different systems based on individualised mean absolute relative difference results has limitations, which have potential clinical implications. Healthcare professionals must understand the factors that influence mean absolute relative difference as a metric for accuracy and look at additional assessments, such as consensus error grid analysis, when evaluating continuous glucose monitoring and flash glucose monitoring systems in diabetes care. This in turn will ensure that management decisions based on interstitial fluid sensor data are both effective and safe.

  9. Accuracy of a new elastomeric impression material for complete-arch dental implant impressions.

    Science.gov (United States)

    Baig, Mirza R; Buzayan, Muaiyed M; Yunus, Norsiah

    2018-05-01

    The aim of the present study was to assess the accuracy of multi-unit dental implant casts obtained from two elastomeric impression materials, vinyl polyether silicone (VPES) and polyether (PE), and to test the effect of splinting of impression copings on the accuracy of implant casts. Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant-abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z-axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non-parametrical Kruskal-Wallis and Mann-Whitney tests at α = .05. The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non-splinting and splinting groups were also not significantly different for both PE and VPES (P>.05). The accuracy of VPES impression material seemed comparable with PE for multi-implant abutment-level impressions. Splinting had no effect on the accuracy of implant impressions. © 2018 John Wiley & Sons Australia, Ltd.

  10. Comparing the accuracy of perturbative and variational calculations for predicting fundamental vibrational frequencies of dihalomethanes

    Science.gov (United States)

    Krasnoshchekov, Sergey V.; Schutski, Roman S.; Craig, Norman C.; Sibaev, Marat; Crittenden, Deborah L.

    2018-02-01

    Three dihalogenated methane derivatives (CH2F2, CH2FCl, and CH2Cl2) were used as model systems to compare and assess the accuracy of two different approaches for predicting observed fundamental frequencies: canonical operator Van Vleck vibrational perturbation theory (CVPT) and vibrational configuration interaction (VCI). For convenience and consistency, both methods employ the Watson Hamiltonian in rectilinear normal coordinates, expanding the potential energy surface (PES) as a Taylor series about equilibrium and constructing the wavefunction from a harmonic oscillator product basis. At the highest levels of theory considered here, fourth-order CVPT and VCI in a harmonic oscillator basis with up to 10 quanta of vibrational excitation in conjunction with a 4-mode representation sextic force field (SFF-4MR) computed at MP2/cc-pVTZ with replacement CCSD(T)/aug-cc-pVQZ harmonic force constants, the agreement between computed fundamentals is closer to 0.3 cm-1 on average, with a maximum difference of 1.7 cm-1. The major remaining accuracy-limiting factors are the accuracy of the underlying electronic structure model, followed by the incompleteness of the PES expansion. Nonetheless, computed and experimental fundamentals agree to within 5 cm-1, with an average difference of 2 cm-1, confirming the utility and accuracy of both theoretical models. One exception to this rule is the formally IR-inactive but weakly allowed through Coriolis-coupling H-C-H out-of-plane twisting mode of dichloromethane, whose spectrum we therefore revisit and reassign. We also investigate convergence with respect to order of CVPT, VCI excitation level, and order of PES expansion, concluding that premature truncation substantially decreases accuracy, although VCI(6)/SFF-4MR results are still of acceptable accuracy, and some error cancellation is observed with CVPT2 using a quartic force field.

  11. DESIGNA ND ANALYSIS FOR THEMATIC MAP ACCURACY ASSESSMENT: FUNDAMENTAL PRINCIPLES

    Science.gov (United States)

    Before being used in scientific investigations and policy decisions, thematic maps constructed from remotely sensed data should be subjected to a statistically rigorous accuracy assessment. The three basic components of an accuracy assessment are: 1) the sampling design used to s...

  12. Precision and accuracy of mechanistic-empirical pavement design

    CSIR Research Space (South Africa)

    Theyse, HL

    2006-09-01

    Full Text Available are discussed in general. The effects of variability and error on the design accuracy and design risk are lastly illustrated at the hand of a simple mechanistic-empirical design problem, showing that the engineering models alone determine the accuracy...

  13. An Investigation to Improve Classifier Accuracy for Myo Collected Data

    Science.gov (United States)

    2017-02-01

    Bad Samples Effect on Classification Accuracy 7 5.1 Naïve Bayes (NB) Classifier Accuracy 7 5.2 Logistic Model Tree (LMT) 10 5.3 K-Nearest Neighbor...gesture, pitch feature, user 06. All samples exhibit reversed movement...20 Fig. A-2 Come gesture, pitch feature, user 14. All samples exhibit reversed movement

  14. Coorientational Accuracy and Differentiation in the Management of Conflict.

    Science.gov (United States)

    Papa, Michael J.; Pood, Elliott A.

    1988-01-01

    Investigates the relationship between coorientational accuracy and differentiation time and two dimensions of conflict (interaction satisfaction and assertiveness of influence strategies). Suggests that entering a conflict with high coorientational accuracy leads to less differentiation and fewer assertive strategies during the confrontation and…

  15. Assessment Of Accuracies Of Remote-Sensing Maps

    Science.gov (United States)

    Card, Don H.; Strong, Laurence L.

    1992-01-01

    Report describes study of accuracies of classifications of picture elements in map derived by digital processing of Landsat-multispectral-scanner imagery of coastal plain of Arctic National Wildlife Refuge. Accuracies of portions of map analyzed with help of statistical sampling procedure called "stratified plurality sampling", in which all picture elements in given cluster classified in stratum to which plurality of them belong.

  16. English Verb Accuracy of Bilingual Cantonese-English Preschoolers

    Science.gov (United States)

    Rezzonico, Stefano; Goldberg, Ahuva; Milburn, Trelani; Belletti, Adriana; Girolametto, Luigi

    2017-01-01

    Purpose: Knowledge of verb development in typically developing bilingual preschoolers may inform clinicians about verb accuracy rates during the 1st 2 years of English instruction. This study aimed to investigate tensed verb accuracy in 2 assessment contexts in 4- and 5-year-old Cantonese-English bilingual preschoolers. Method: The sample included…

  17. Accuracy assessment of airborne laser scanning strips using planar features

    NARCIS (Netherlands)

    Soudarissanane, S.S.; Van der Sande, C.J.; Khoshelham, K.

    2010-01-01

    Airborne Laser Scanning (ALS) is widely used in many applications for its high measurement accuracy, fast acquisition capability, and large spatial coverage. Accuracy assessment of the ALS data usually relies on comparing corresponding tie elements, often points or lines, in the overlapping strips.

  18. Using inferred probabilities to measure the accuracy of imprecise forecasts

    Directory of Open Access Journals (Sweden)

    Paul Lehner

    2012-11-01

    Full Text Available Research on forecasting is effectively limited to forecasts that are expressed with clarity; which is to say that the forecasted event must be sufficiently well-defined so that it can be clearly resolved whether or not the event occurred and forecasts certainties are expressed as quantitative probabilities. When forecasts are expressed with clarity, then quantitative measures (scoring rules, calibration, discrimination, etc. can be used to measure forecast accuracy, which in turn can be used to measure the comparative accuracy of different forecasting methods. Unfortunately most real world forecasts are not expressed clearly. This lack of clarity extends to both the description of the forecast event and to the use of vague language to express forecast certainty. It is thus difficult to assess the accuracy of most real world forecasts, and consequently the accuracy the methods used to generate real world forecasts. This paper addresses this deficiency by presenting an approach to measuring the accuracy of imprecise real world forecasts using the same quantitative metrics routinely used to measure the accuracy of well-defined forecasts. To demonstrate applicability, the Inferred Probability Method is applied to measure the accuracy of forecasts in fourteen documents examining complex political domains. Key words: inferred probability, imputed probability, judgment-based forecasting, forecast accuracy, imprecise forecasts, political forecasting, verbal probability, probability calibration.

  19. 12 CFR 740.2 - Accuracy of advertising.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Accuracy of advertising. 740.2 Section 740.2... ADVERTISING AND NOTICE OF INSURED STATUS § 740.2 Accuracy of advertising. No insured credit union may use any advertising (which includes print, electronic, or broadcast media, displays and signs, stationery, and other...

  20. Does a Structured Data Collection Form Improve The Accuracy of ...

    African Journals Online (AJOL)

    and multiple etiologies for similar presentation. Standardized forms may harmonize the initial assessment, improve accuracy of diagnosis and enhance outcomes. Objectives: To determine the extent to which use of a structured data collection form (SDCF) affected the diagnostic accuracy of AAP. Methodology: A before and ...

  1. Quantifying the Accuracy of a Diagnostic Test or Marker

    NARCIS (Netherlands)

    Linnet, Kristian; Bossuyt, Patrick M. M.; Moons, Karel G. M.; Reitsma, Johannes B. R.

    2012-01-01

    BACKGROUND: In recent years, increasing focus has been directed to the methodology for evaluating (new) tests or biomarkers. A key step in the evaluation of a diagnostic test is the investigation into its accuracy. CONTENT: We reviewed the literature on how to assess the accuracy of diagnostic

  2. Concept Mapping Improves Metacomprehension Accuracy among 7th Graders

    Science.gov (United States)

    Redford, Joshua S.; Thiede, Keith W.; Wiley, Jennifer; Griffin, Thomas D.

    2012-01-01

    Two experiments explored concept map construction as a useful intervention to improve metacomprehension accuracy among 7th grade students. In the first experiment, metacomprehension was marginally better for a concept mapping group than for a rereading group. In the second experiment, metacomprehension accuracy was significantly greater for a…

  3. Deception Detection: Accuracy Levels Among International Military Officers Using Content and Contextual Questioning Methods

    Science.gov (United States)

    2016-12-01

    deception than any one method on its own. This research project focuses on students at the Naval Postgraduate School (NPS) in Monterey, CA, to...international military officers were also limited on the type of contextual questioning methods and scenarios. These scenarios were not a very good ...research received participation from 52 students . Although the sample size was small, proportionally, 24% is a good response rate for lab research

  4. Energy Measurement with the ATLAS Electromagnetic Calorimeter at the Per Mill Accuracy Level

    CERN Document Server

    Teischinger, Florian; Fabjan, Christian

    The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. It is made up of various sub-detectors to measure the properties of all the particles produced at the proton-proton collision. Over the last three years of running around 20 x 10^14 collisions of proton data have been recorded. Liquid argon (LAr) sampling calorimeters are used for all electromagnetic calorimetry and for hadronic calorimetry in the end-caps. The Inner Detector, on the other hand, measures the transverse momentum of charged particles down to a momentum of 0.5 GeV. This thesis deals with the absolute measurement of the energy in the electromagnetic calorimeter and the improvement of the systematic uncertainties. A method using the ratio of the energy E in the calorimeter and the momentum measurement p in the Inner Detector (E/p) was used to extract the energy scale of the electromagnetic LAr calorimeter for electrons and positrons. To investigate and further reduce the syst...

  5. Influence of scanning system and dentist's level of training in the accuracy of digital impressions

    Science.gov (United States)

    Hategan, Simona; Gabor, Alin; Zaharia, Cristian; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Jivanescu, Anca

    2016-03-01

    Background: The principal aim of our study was to evaluate digital impressions, taken with spray powder and powderfree scan systems, in order to determine the influence of the dentist's commitment to training as a critical factor regarding quality. Material and method: Two digital intraoral impression systems from the same manufacture (Sirona) : Apollo DI and CEREC Omnicam, were used to scan 16 crown preparations on teeth on a typodont maxillary model. Because an Apollo Di intraoral camera is a powder system, an adhesive was applied before using the powder spray. Three groups were used to scan the crown preparations in order to determine coating thickness homogeneity. One group consisted of senior year dental students, a second consisted of prosthodontics residents, and the third consisted of prosthodontics specialists. The same procedure was applied with a CEREC Omnicam intraoral camera, which is a powder-free system. By using the two systems software parameters we were able to determine the scanning precision. Results: Homogeneity scores for Apollo Di regarding the spray layer was significantly thinner for all dental surfaces in the first group, while the second group had thinner coatings for buccal and distal surfaces. For the third group, the crown preparations were coated more homogeneously than the first two groups. The powder-free system CEREC Omnicam can, to a degree, mask the lack of experience in direct optical impressions by avoiding the poor quality coating, which can lead to defective marginal adaptation of definitive restoration. Conclusions: The dentist's lack of experience can be mitigated, and partially avoided, by using powder-free systems. At the same time, the dentist can give more time towards learning how to integrate computerized fabricated restoration into the practice. The commitment to training is a critical factor in the successful integration of the technology. In addition, scanning marginal preparation details needs time in order to develop technical and manual skills.

  6. Testing an Automated Accuracy Assessment Method on Bibliographic Data

    Directory of Open Access Journals (Sweden)

    Marlies Olensky

    2014-12-01

    Full Text Available This study investigates automated data accuracy assessment as described in data quality literature for its suitability to assess bibliographic data. The data samples comprise the publications of two Nobel Prize winners in the field of Chemistry for a 10-year-publication period retrieved from the two bibliometric data sources, Web of Science and Scopus. The bibliographic records are assessed against the original publication (gold standard and an automatic assessment method is compared to a manual one. The results show that the manual assessment method reflects truer accuracy scores. The automated assessment method would need to be extended by additional rules that reflect specific characteristics of bibliographic data. Both data sources had higher accuracy scores per field than accumulated per record. This study contributes to the research on finding a standardized assessment method of bibliographic data accuracy as well as defining the impact of data accuracy on the citation matching process.

  7. Accuracy optimization with wavelength tunability in overlay imaging technology

    Science.gov (United States)

    Lee, Honggoo; Kang, Yoonshik; Han, Sangjoon; Shim, Kyuchan; Hong, Minhyung; Kim, Seungyoung; Lee, Jieun; Lee, Dongyoung; Oh, Eungryong; Choi, Ahlin; Kim, Youngsik; Marciano, Tal; Klein, Dana; Hajaj, Eitan M.; Aharon, Sharon; Ben-Dov, Guy; Lilach, Saltoun; Serero, Dan; Golotsvan, Anna

    2018-03-01

    As semiconductor manufacturing technology progresses and the dimensions of integrated circuit elements shrink, overlay budget is accordingly being reduced. Overlay budget closely approaches the scale of measurement inaccuracies due to both optical imperfections of the measurement system and the interaction of light with geometrical asymmetries of the measured targets. Measurement inaccuracies can no longer be ignored due to their significant effect on the resulting device yield. In this paper we investigate a new approach for imaging based overlay (IBO) measurements by optimizing accuracy rather than contrast precision, including its effect over the total target performance, using wavelength tunable overlay imaging metrology. We present new accuracy metrics based on theoretical development and present their quality in identifying the measurement accuracy when compared to CD-SEM overlay measurements. The paper presents the theoretical considerations and simulation work, as well as measurement data, for which tunability combined with the new accuracy metrics is shown to improve accuracy performance.

  8. Variation in Microbial Identification System Accuracy for Yeast Identification Depending on Commercial Source of Sabouraud Dextrose Agar

    OpenAIRE

    Kellogg, James A.; Bankert, David A.; Chaturvedi, Vishnu

    1999-01-01

    The accuracy of the Microbial Identification System (MIS; MIDI, Inc.) for identification of yeasts to the species level was compared by using 438 isolates grown on prepoured BBL Sabouraud dextrose agar (SDA) and prepoured Remel SDA. Correct identification was observed for 326 (74%) of the yeasts cultured on BBL SDA versus only 214 (49%) of yeasts grown on Remel SDA (P < 0.001). The commercial source of the SDA used in the MIS procedure significantly influences the system’s accuracy.

  9. Variation in Microbial Identification System accuracy for yeast identification depending on commercial source of Sabouraud dextrose agar.

    Science.gov (United States)

    Kellogg, J A; Bankert, D A; Chaturvedi, V

    1999-06-01

    The accuracy of the Microbial Identification System (MIS; MIDI, Inc. ) for identification of yeasts to the species level was compared by using 438 isolates grown on prepoured BBL Sabouraud dextrose agar (SDA) and prepoured Remel SDA. Correct identification was observed for 326 (74%) of the yeasts cultured on BBL SDA versus only 214 (49%) of yeasts grown on Remel SDA (P < 0.001). The commercial source of the SDA used in the MIS procedure significantly influences the system's accuracy.

  10. Perceptual Load Affects Eyewitness Accuracy & Susceptibility to Leading Questions

    Directory of Open Access Journals (Sweden)

    Gillian Murphy

    2016-08-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  12. Determining the Accuracy of Crowdsourced Tweet Verification for Auroral Research

    Directory of Open Access Journals (Sweden)

    Nathan A. Case

    2016-12-01

    Full Text Available The Aurorasaurus project harnesses volunteer crowdsourcing to identify sightings of an aurora (the “northern/southern lights” posted by citizen scientists on Twitter. Previous studies have demonstrated that aurora sightings can be mined from Twitter with the caveat that there is a large background level of non-sighting tweets, especially during periods of low auroral activity. Aurorasaurus attempts to mitigate this, and thus increase the quality of its Twitter sighting data, by using volunteers to sift through a pre-filtered list of geolocated tweets to verify real-time aurora sightings. In this study, the current implementation of this crowdsourced verification system, including the process of geolocating tweets, is described and its accuracy (which, overall, is found to be 68.4% is determined. The findings suggest that citizen science volunteers are able to accurately filter out unrelated, spam-like, Twitter data but struggle when filtering out somewhat related, yet undesired, data. The citizen scientists particularly struggle with determining the real-time nature of the sightings, so care must be taken when relying on crowdsourced identification.

  13. Financial forecasts accuracy in Brazil's social security system.

    Directory of Open Access Journals (Sweden)

    Carlos Patrick Alves da Silva

    Full Text Available Long-term social security statistical forecasts produced and disseminated by the Brazilian government aim to provide accurate results that would serve as background information for optimal policy decisions. These forecasts are being used as support for the government's proposed pension reform that plans to radically change the Brazilian Constitution insofar as Social Security is concerned. However, the reliability of official results is uncertain since no systematic evaluation of these forecasts has ever been published by the Brazilian government or anyone else. This paper aims to present a study of the accuracy and methodology of the instruments used by the Brazilian government to carry out long-term actuarial forecasts. We base our research on an empirical and probabilistic analysis of the official models. Our empirical analysis shows that the long-term Social Security forecasts are systematically biased in the short term and have significant errors that render them meaningless in the long run. Moreover, the low level of transparency in the methods impaired the replication of results published by the Brazilian Government and the use of outdated data compromises forecast results. In the theoretical analysis, based on a mathematical modeling approach, we discuss the complexity and limitations of the macroeconomic forecast through the computation of confidence intervals. We demonstrate the problems related to error measurement inherent to any forecasting process. We then extend this exercise to the computation of confidence intervals for Social Security forecasts. This mathematical exercise raises questions about the degree of reliability of the Social Security forecasts.

  14. Financial forecasts accuracy in Brazil's social security system.

    Science.gov (United States)

    Silva, Carlos Patrick Alves da; Puty, Claudio Alberto Castelo Branco; Silva, Marcelino Silva da; Carvalho, Solon Venâncio de; Francês, Carlos Renato Lisboa

    2017-01-01

    Long-term social security statistical forecasts produced and disseminated by the Brazilian government aim to provide accurate results that would serve as background information for optimal policy decisions. These forecasts are being used as support for the government's proposed pension reform that plans to radically change the Brazilian Constitution insofar as Social Security is concerned. However, the reliability of official results is uncertain since no systematic evaluation of these forecasts has ever been published by the Brazilian government or anyone else. This paper aims to present a study of the accuracy and methodology of the instruments used by the Brazilian government to carry out long-term actuarial forecasts. We base our research on an empirical and probabilistic analysis of the official models. Our empirical analysis shows that the long-term Social Security forecasts are systematically biased in the short term and have significant errors that render them meaningless in the long run. Moreover, the low level of transparency in the methods impaired the replication of results published by the Brazilian Government and the use of outdated data compromises forecast results. In the theoretical analysis, based on a mathematical modeling approach, we discuss the complexity and limitations of the macroeconomic forecast through the computation of confidence intervals. We demonstrate the problems related to error measurement inherent to any forecasting process. We then extend this exercise to the computation of confidence intervals for Social Security forecasts. This mathematical exercise raises questions about the degree of reliability of the Social Security forecasts.

  15. Financial forecasts accuracy in Brazil’s social security system

    Science.gov (United States)

    2017-01-01

    Long-term social security statistical forecasts produced and disseminated by the Brazilian government aim to provide accurate results that would serve as background information for optimal policy decisions. These forecasts are being used as support for the government’s proposed pension reform that plans to radically change the Brazilian Constitution insofar as Social Security is concerned. However, the reliability of official results is uncertain since no systematic evaluation of these forecasts has ever been published by the Brazilian government or anyone else. This paper aims to present a study of the accuracy and methodology of the instruments used by the Brazilian government to carry out long-term actuarial forecasts. We base our research on an empirical and probabilistic analysis of the official models. Our empirical analysis shows that the long-term Social Security forecasts are systematically biased in the short term and have significant errors that render them meaningless in the long run. Moreover, the low level of transparency in the methods impaired the replication of results published by the Brazilian Government and the use of outdated data compromises forecast results. In the theoretical analysis, based on a mathematical modeling approach, we discuss the complexity and limitations of the macroeconomic forecast through the computation of confidence intervals. We demonstrate the problems related to error measurement inherent to any forecasting process. We then extend this exercise to the computation of confidence intervals for Social Security forecasts. This mathematical exercise raises questions about the degree of reliability of the Social Security forecasts. PMID:28859172

  16. High accuracy mantle convection simulation through modern numerical methods

    KAUST Repository

    Kronbichler, Martin

    2012-08-21

    Numerical simulation of the processes in the Earth\\'s mantle is a key piece in understanding its dynamics, composition, history and interaction with the lithosphere and the Earth\\'s core. However, doing so presents many practical difficulties related to the numerical methods that can accurately represent these processes at relevant scales. This paper presents an overview of the state of the art in algorithms for high-Rayleigh number flows such as those in the Earth\\'s mantle, and discusses their implementation in the Open Source code Aspect (Advanced Solver for Problems in Earth\\'s ConvecTion). Specifically, we show how an interconnected set of methods for adaptive mesh refinement (AMR), higher order spatial and temporal discretizations, advection stabilization and efficient linear solvers can provide high accuracy at a numerical cost unachievable with traditional methods, and how these methods can be designed in a way so that they scale to large numbers of processors on compute clusters. Aspect relies on the numerical software packages deal.II and Trilinos, enabling us to focus on high level code and keeping our implementation compact. We present results from validation tests using widely used benchmarks for our code, as well as scaling results from parallel runs. © 2012 The Authors Geophysical Journal International © 2012 RAS.

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Lathe leveler

    Energy Technology Data Exchange (ETDEWEB)

    Lovelady, III, Michael W.J.

    2018-03-06

    A lathe leveler for centering a cutting tool in relation to a cylindrical work piece includes a first leveling arm having a first contact point disposed adjacent a distal end of the first leveling arm, a second leveling arm having a second contact point disposed adjacent a distal end of the second leveling arm, a leveling gage, and a leveling plate having a cutting tool receiving surface positioned parallel to a horizontal axis of the leveling gage and on a same plane as a midpoint of the first contact point and the second contact point. The leveling arms and leveling plate are dimensioned and configured such that the cutting tool receiving surface is centered in relation to the work piece when the first and second contact points are in contact with one of the inner surface and outer surface of the cylindrical work piece and the leveling gage is centered.

  19. Precision and Accuracy in PDV and VISAR

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, W. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-22

    This is a technical report discussing our current level of understanding of a wide and varying distribution of uncertainties in velocity results from Photonic Doppler Velocimetry in its application to gas gun experiments. Using propagation of errors methods with statistical averaging of photon number fluctuation in the detected photocurrent and subsequent addition of electronic recording noise, we learn that the velocity uncertainty in VISAR can be written in closed form. For PDV, the non-linear frequency transform and peak fitting methods employed make propagation of errors estimates notoriously more difficult to write down in closed form expect in the limit of constant velocity and low time resolution (large analysis-window width). An alternative method of error propagation in PDV is to use Monte Carlo methods with a simulation of the time domain signal based on results from the spectral domain. A key problem for Monte Carlo estimation for an experiment is a correct estimate of that portion of the time-domain noise associated with the peak-fitting region-of-interesting in the spectral domain. Using short-time Fourier transformation spectral analysis and working with the phase dependent real and imaginary parts allows removal of amplitude-noise cross terms that invariably show up when working with correlation-based methods or FFT power spectra. Estimation of the noise associated with a given spectral region of interest is then possible. At this level of progress, we learn that Monte Carlo trials with random recording noise and initial (uncontrolled) phase yields velocity uncertainties that are not as large as those observed. In a search for additional noise sources, a speckleinterference modulation contribution with off axis rays was investigated, and was found to add a velocity variation beyond that from the recording noise (due to random interference between off axis rays), but in our experiments the speckle modulation precision was not as important as the

  20. How does language model size effects speech recognition accuracy for the Turkish language?

    Directory of Open Access Journals (Sweden)

    Behnam ASEFİSARAY

    2016-05-01

    Full Text Available In this paper we aimed at investigating the effect of Language Model (LM size on Speech Recognition (SR accuracy. We also provided details of our approach for obtaining the LM for Turkish. Since LM is obtained by statistical processing of raw text, we expect that by increasing the size of available data for training the LM, SR accuracy will improve. Since this study is based on recognition of Turkish, which is a highly agglutinative language, it is important to find out the appropriate size for the training data. The minimum required data size is expected to be much higher than the data needed to train a language model for a language with low level of agglutination such as English. In the experiments we also tried to adjust the Language Model Weight (LMW and Active Token Count (ATC parameters of LM as these are expected to be different for a highly agglutinative language. We showed that by increasing the training data size to an appropriate level, the recognition accuracy improved on the other hand changes on LMW and ATC did not have a positive effect on Turkish speech recognition accuracy.

  1. Quantifying the Climate-Scale Accuracy of Satellite Cloud Retrievals

    Science.gov (United States)

    Roberts, Y.; Wielicki, B. A.; Sun-Mack, S.; Minnis, P.; Liang, L.; Di Girolamo, L.

    2014-12-01

    Instrument calibration and cloud retrieval algorithms have been developed to minimize retrieval errors on small scales. However, measurement uncertainties and assumptions within retrieval algorithms at the pixel level may alias into decadal-scale trends of cloud properties. We first, therefore, quantify how instrument calibration changes could alias into cloud property trends. For a perfect observing system the climate trend accuracy is limited only by the natural variability of the climate variable. Alternatively, for an actual observing system, the climate trend accuracy is additionally limited by the measurement uncertainty. Drifts in calibration over time may therefore be disguised as a true climate trend. We impose absolute calibration changes to MODIS spectral reflectance used as input to the CERES Cloud Property Retrieval System (CPRS) and run the modified MODIS reflectance through the CPRS to determine the sensitivity of cloud properties to calibration changes. We then use these changes to determine the impact of instrument calibration changes on trend uncertainty in reflected solar cloud properties. Secondly, we quantify how much cloud retrieval algorithm assumptions alias into cloud optical retrieval trends by starting with the largest of these biases: the plane-parallel assumption in cloud optical thickness (τC) retrievals. First, we collect liquid water cloud fields obtained from Multi-angle Imaging Spectroradiometer (MISR) measurements to construct realistic probability distribution functions (PDFs) of 3D cloud anisotropy (a measure of the degree to which clouds depart from plane-parallel) for different ISCCP cloud types. Next, we will conduct a theoretical study with dynamically simulated cloud fields and a 3D radiative transfer model to determine the relationship between 3D cloud anisotropy and 3D τC bias for each cloud type. Combining these results provides distributions of 3D τC bias by cloud type. Finally, we will estimate the change in

  2. Dispositional malevolence and impression formation: Dark Tetrad associations with accuracy and positivity in first impressions.

    Science.gov (United States)

    Rogers, Katherine H; Le, Marina T; Buckels, Erin E; Kim, Mikayla; Biesanz, Jeremy C

    2018-02-19

    The Dark Tetrad traits (subclinical psychopathy, narcissism, Machiavellianism, and everyday sadism) have interpersonal consequences. At present, however, how these traits are associated with the accuracy and positivity of first impressions is not well understood. The present article addresses three primary questions. First, to what extent are perceiver levels of Dark Tetrad traits associated with differing levels of perceptive accuracy? Second, to what extent are target levels of Dark Tetrad traits associated with differing levels of expressive accuracy? Finally, to what extent can Dark Tetrad traits be differentiated when examining perceptions of and by others? In a round-robin design, undergraduate participants (N = 412) in small groups engaged in brief, naturalistic, unstructured dyadic interactions before providing impressions of their partner. Dark Tetrad traits were associated with being viewed and viewing others less distinctively accurately and more negatively. Interpersonal perceptions that included an individual scoring highly on one of the Dark Tetrad traits differed in important ways from interactions among individuals with more benevolent personalities. Notably, despite the similarities between the Dark Tetrad, traits had unique associations with interpersonal perceptions. © 2018 Wiley Periodicals, Inc.

  3. Fragmentation of DNA affects the accuracy of the DNA quantitation by the commonly used methods

    Directory of Open Access Journals (Sweden)

    Sedlackova Tatiana

    2013-02-01

    Full Text Available Abstract Background Specific applications and modern technologies, like non-invasive prenatal testing, non-invasive cancer diagnostic and next generation sequencing, are currently in the focus of researchers worldwide. These have common characteristics in use of highly fragmented DNA molecules for analysis. Hence, for the performance of molecular methods, DNA concentration is a crucial parameter; we compared the influence of different levels of DNA fragmentation on the accuracy of DNA concentration measurements. Results In our comparison, the performance of the currently most commonly used methods for DNA concentration measurement (spectrophotometric, fluorometric and qPCR based were tested on artificially fragmented DNA samples. In our comparison, unfragmented and three specifically fragmented DNA samples were used. According to our results, the level of fragmentation did not influence the accuracy of spectrophotometric measurements of DNA concentration, while other methods, fluorometric as well as qPCR-based, were significantly influenced and a decrease in measured concentration was observed with more intensive DNA fragmentation. Conclusions Our study has confirmed that the level of fragmentation of DNA has significant impact on accuracy of DNA concentration measurement with two of three mostly used methods (PicoGreen and qPCR. Only spectrophotometric measurement was not influenced by the level of fragmentation, but sensitivity of this method was lowest among the three tested. Therefore if it is possible the DNA quantification should be performed with use of equally fragmented control DNA.

  4. ACCURACY ASSESSMENT OF COASTAL TOPOGRAPHY DERIVED FROM UAV IMAGES

    Directory of Open Access Journals (Sweden)

    N. Long

    2016-06-01

    Full Text Available 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.

  5. Accuracy of Genomic Selection in a Rice Synthetic Population Developed for Recurrent Selection Breeding.

    Directory of Open Access Journals (Sweden)

    Cécile Grenier

    Full Text Available Genomic selection (GS is a promising strategy for enhancing genetic gain. We investigated the accuracy of genomic estimated breeding values (GEBV in four inter-related synthetic populations that underwent several cycles of recurrent selection in an upland rice-breeding program. A total of 343 S2:4 lines extracted from those populations were phenotyped for flowering time, plant height, grain yield and panicle weight, and genotyped with an average density of one marker per 44.8 kb. The relative effect of the linkage disequilibrium (LD and minor allele frequency (MAF thresholds for selecting markers, the relative size of the training population (TP and of the validation population (VP, the selected trait and the genomic prediction models (frequentist and Bayesian on the accuracy of GEBVs was investigated in 540 cross validation experiments with 100 replicates. The effect of kinship between the training and validation populations was tested in an additional set of 840 cross validation experiments with a single genomic prediction model. LD was high (average r2 = 0.59 at 25 kb and decreased slowly, distribution of allele frequencies at individual loci was markedly skewed toward unbalanced frequencies (MAF average value 15.2% and median 9.6%, and differentiation between the four synthetic populations was low (FST ≤0.06. The accuracy of GEBV across all cross validation experiments ranged from 0.12 to 0.54 with an average of 0.30. Significant differences in accuracy were observed among the different levels of each factor investigated. Phenotypic traits had the biggest effect, and the size of the incidence matrix had the smallest. Significant first degree interaction was observed for GEBV accuracy between traits and all the other factors studied, and between prediction models and LD, MAF and composition of the TP. The potential of GS to accelerate genetic gain and breeding options to increase the accuracy of predictions are discussed.

  6. Accuracy of Genomic Selection in a Rice Synthetic Population Developed for Recurrent Selection Breeding.

    Science.gov (United States)

    Grenier, Cécile; Cao, Tuong-Vi; Ospina, Yolima; Quintero, Constanza; Châtel, Marc Henri; Tohme, Joe; Courtois, Brigitte; Ahmadi, Nourollah

    2015-01-01

    Genomic selection (GS) is a promising strategy for enhancing genetic gain. We investigated the accuracy of genomic estimated breeding values (GEBV) in four inter-related synthetic populations that underwent several cycles of recurrent selection in an upland rice-breeding program. A total of 343 S2:4 lines extracted from those populations were phenotyped for flowering time, plant height, grain yield and panicle weight, and genotyped with an average density of one marker per 44.8 kb. The relative effect of the linkage disequilibrium (LD) and minor allele frequency (MAF) thresholds for selecting markers, the relative size of the training population (TP) and of the validation population (VP), the selected trait and the genomic prediction models (frequentist and Bayesian) on the accuracy of GEBVs was investigated in 540 cross validation experiments with 100 replicates. The effect of kinship between the training and validation populations was tested in an additional set of 840 cross validation experiments with a single genomic prediction model. LD was high (average r2 = 0.59 at 25 kb) and decreased slowly, distribution of allele frequencies at individual loci was markedly skewed toward unbalanced frequencies (MAF average value 15.2% and median 9.6%), and differentiation between the four synthetic populations was low (FST ≤0.06). The accuracy of GEBV across all cross validation experiments ranged from 0.12 to 0.54 with an average of 0.30. Significant differences in accuracy were observed among the different levels of each factor investigated. Phenotypic traits had the biggest effect, and the size of the incidence matrix had the smallest. Significant first degree interaction was observed for GEBV accuracy between traits and all the other factors studied, and between prediction models and LD, MAF and composition of the TP. The potential of GS to accelerate genetic gain and breeding options to increase the accuracy of predictions are discussed.

  7. Dr Google: The readability and accuracy of patient education websites for Graves' disease treatment.

    Science.gov (United States)

    Purdy, Amanda C; Idriss, Almoatazbellah; Ahern, Susan; Lin, Elizabeth; Elfenbein, Dawn M

    2017-11-01

    National guidelines emphasize the importance of incorporating patient preferences into the recommendations for the treatment of Graves' disease. Many patients use the Internet to obtain health information, and search results can affect their treatment decisions. This study compares the readability and accuracy of patient-oriented online resources for the treatment of Graves' disease by website affiliation and treatment modality. A systematic Internet search was used to identify the top websites discussing the treatment of Graves' disease. Readability was measured using 5 standardized tests. Accuracy was assessed by a blinded, expert panel, which scored the accuracy of sites on a scale of 1 to 5. Mean readability and accuracy scores were compared among website affiliations and treatment modalities. We identified 13 unique websites, including 2 academic, 2 government, 5 nonprofit, and 4 private sites. There was a difference in both readability (mean 13.2, range 9.1-15.7, P = .003) and accuracy (mean 4.04, range 2.75-4.50, P = .019) based on website affiliation. Government sites (mean readability 11.1) were easier to read than academic (14.3, P < .01), nonprofit (13.9, P < .01), and private sites (13.5, P < .05). Academic sites (mean accuracy 4.50) were more accurate than private sites (3.56, P < .05). Online patient resources for the treatment of Graves' disease are written at an inappropriately high reading level. Academic sites contain both the most accurate and the most difficult to read information. Private sites represented the majority of our top results but contained the least accurate information. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Procedural Documentation and Accuracy Assessment of Bathymetric Maps and Area/Capacity Tables for Small Reservoirs

    Science.gov (United States)

    Wilson, Gary L.; Richards, Joseph M.

    2006-01-01

    Because of the increasing use and importance of lakes for water supply to communities, a repeatable and reliable procedure to determine lake bathymetry and capacity is needed. A method to determine the accuracy of the procedure will help ensure proper collection and use of the data and resulting products. It is important to clearly define the intended products and desired accuracy before conducting the bathymetric survey to ensure proper data collection. A survey-grade echo sounder and differential global positioning system receivers were used to collect water-depth and position data in December 2003 at Sugar Creek Lake near Moberly, Missouri. Data were collected along planned transects, with an additional set of quality-assurance data collected for use in accuracy computations. All collected data were imported into a geographic information system database. A bathymetric surface model, contour map, and area/capacity tables were created from the geographic information system database. An accuracy assessment was completed on the collected data, bathymetric surface model, area/capacity table, and contour map products. Using established vertical accuracy standards, the accuracy of the collected data, bathymetric surface model, and contour map product was 0.67 foot, 0.91 foot, and 1.51 feet at the 95 percent confidence level. By comparing results from different transect intervals with the quality-assurance transect data, it was determined that a transect interval of 1 percent of the longitudinal length of Sugar Creek Lake produced nearly as good results as 0.5 percent transect interval for the bathymetric surface model, area/capacity table, and contour map products.

  9. Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

    Science.gov (United States)

    Duman, Huseyin; Ugur Sanli, D.

    2016-04-01

    Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

  10. Significant improvement of accuracy and precision in the determination of trace rare earths by fluorescence analysis

    International Nuclear Information System (INIS)

    Ozawa, L.; Hersh, H.N.

    1976-01-01

    Most of the rare earths in yttrium, gadolinium and lanthanum oxides emit characteristic fluorescent line spectra under irradiation with photons, electrons and x rays. The sensitivity and selectivity of the rare earth fluorescences are high enough to determine the trace amounts (0.01 to 100 ppM) of rare earths. The absolute fluorescent intensities of solids, however, are markedly affected by the synthesis procedure, level of contamination and crystal perfection, resulting in poor accuracy and low precision for the method (larger than 50 percent error). Special care in preparation of the samples is required to obtain good accuracy and precision. It is found that the accuracy and precision for the determination of trace (less than 10 ppM) rare earths by fluorescence analysis improved significantly, while still maintaining the sensitivity, when the determination is made by comparing the ratio of the fluorescent intensities of the trace rare earths to that of a deliberately added rare earth as reference. The variation in the absolute fluorescent intensity remains, but is compensated for by measuring the fluorescent line intensity ratio. Consequently, the determination of trace rare earths (with less than 3 percent error) is easily made by a photoluminescence technique in which the rare earths are excited directly by photons. Accuracy is still maintained when the absolute fluorescent intensity is reduced by 50 percent through contamination by Ni, Fe, Mn or Pb (about 100 ppM). Determination accuracy is also improved for fluorescence analysis by electron excitation and x-ray excitation. For some rare earths, however, accuracy by these techniques is reduced because indirect excitation mechanisms are involved. The excitation mechanisms and the interferences between rare earths are also reported

  11. Determination of material irradiation parameters. Required accuracies and available methods

    International Nuclear Information System (INIS)

    Cerles, J.M.; Mas, P.

    1978-01-01

    In this paper, the author reports some main methods to determine the nuclear parameters of material irradiation in testing reactor (nuclear power, burn-up, fluxes, fluences, ...). The different methods (theoretical or experimental) are reviewed: neutronics measurements and calculations, gamma scanning, thermal balance, ... The required accuracies are reviewed: they are of 3-5% on flux, fluences, nuclear power, burn-up, conversion factor, ... These required accuracies are compared with the real accuracies available which are at the present time of order of 5-20% on these parameters

  12. Surgical accuracy of three-dimensional virtual planning

    DEFF Research Database (Denmark)

    Stokbro, Kasper; Aagaard, Esben; Torkov, Peter

    2016-01-01

    This retrospective study evaluated the precision and positional accuracy of different orthognathic procedures following virtual surgical planning in 30 patients. To date, no studies of three-dimensional virtual surgical planning have evaluated the influence of segmentation on positional accuracy...... and transverse expansion. Furthermore, only a few have evaluated the precision and accuracy of genioplasty in placement of the chin segment. The virtual surgical plan was compared with the postsurgical outcome by using three linear and three rotational measurements. The influence of maxillary segmentation...

  13. Determination of fuel irradiation parameters. Required accuracies and available methods

    International Nuclear Information System (INIS)

    Mas, P.

    1977-01-01

    This paper reports on the present point of some main methods to determine the nuclear parameters of fuel irradiation in testing reactors (nuclear power, burn up, ...) The different methods (theoretical or experimental) are reviewed: neutron measurements and calculations, gamma scanning, heat balance, ... . The required accuracies are reviewed: they are of 3-5 % on flux, fluences, nuclear power, burn-up, conversion factor. These required accuracies are compared with the real accuracies available which are the present time of order of 5-20 % on these parameters

  14. Analysis of spatial distribution of land cover maps accuracy

    Science.gov (United States)

    Khatami, R.; Mountrakis, G.; Stehman, S. V.

    2017-12-01

    Land cover maps have become one of the most important products of remote sensing science. However, classification errors will exist in any classified map and affect the reliability of subsequent map usage. Moreover, classification accuracy often varies over different regions of a classified map. These variations of accuracy will affect the reliability of subsequent analyses of different regions based on the classified maps. The traditional approach of map accuracy assessment based on an error matrix does not capture the spatial variation in classification accuracy. Here, per-pixel accuracy prediction methods are proposed based on interpolating accuracy values from a test sample to produce wall-to-wall accuracy maps. Different accuracy prediction methods were developed based on four factors: predictive domain (spatial versus spectral), interpolation function (constant, linear, Gaussian, and logistic), incorporation of class information (interpolating each class separately versus grouping them together), and sample size. Incorporation of spectral domain as explanatory feature spaces of classification accuracy interpolation was done for the first time in this research. Performance of the prediction methods was evaluated using 26 test blocks, with 10 km × 10 km dimensions, dispersed throughout the United States. The performance of the predictions was evaluated using the area under the curve (AUC) of the receiver operating characteristic. Relative to existing accuracy prediction methods, our proposed methods resulted in improvements of AUC of 0.15 or greater. Evaluation of the four factors comprising the accuracy prediction methods demonstrated that: i) interpolations should be done separately for each class instead of grouping all classes together; ii) if an all-classes approach is used, the spectral domain will result in substantially greater AUC than the spatial domain; iii) for the smaller sample size and per-class predictions, the spectral and spatial domain

  15. The Accuracy Of Fuzzy Sugeno Method With Antropometry On Determination Natural Patient Status

    Science.gov (United States)

    Syahputra, Dinur; Tulus; Sawaluddin

    2017-12-01

    Anthropometry is one of the processes that can be used to assess nutritional status. In general anthropometry is defined as body size in terms of nutrition, then anthropometry is reviewed from various age levels and nutritional levels. Nutritional status is a description of the balance between nutritional intake with the needs of the body individually. Fuzzy logic is a logic that has a vagueness between right and wrong or between 0 and 1. Sugeno method is used because in the process of calculating nutritional status so far is still done by anthropometry. Currently information technology is growing in any aspect, one of them in the aspect of calculation with data taken from anthropometry. In this case the calculation can use the Fuzzy Sugeno Method, in order to know the great accuracy obtained. Then the results obtained using fuzzy sugeno integrated with anthropometry has an accuracy of 81.48%.

  16. Improved Accuracy of Density Functional Theory Calculations for CO2 Reduction and Metal-Air Batteries

    DEFF Research Database (Denmark)

    Christensen, Rune; Hansen, Heine Anton; Vegge, Tejs

    2015-01-01

    Density functional theory (DFT) calculations have greatly contributed to the atomic level understanding of electrochemical reactions. However, in some cases, the accuracy can be prohibitively low for a detailed understanding of, e.g. reaction mechanisms. Two cases are examined here, i.e. the elec......Density functional theory (DFT) calculations have greatly contributed to the atomic level understanding of electrochemical reactions. However, in some cases, the accuracy can be prohibitively low for a detailed understanding of, e.g. reaction mechanisms. Two cases are examined here, i.......47 eV and 0.17 eV using metals as reference. The presented approach for error identification is expected to be applicable to a very broad range of systems. References: [1] A. A. Peterson, F. Abild-Pedersen, F. Studt, J. Rossmeisl, and J. K. Nørskov, Energy Environ. Sci., 3,1311 (2010) [2] F. Studt, F...

  17. Cortisol level

    Science.gov (United States)

    ... enable JavaScript. The cortisol blood test measures the level of cortisol in the blood. Cortisol is a ... in the morning. This is important, because cortisol level varies throughout the day. You may be asked ...

  18. Triglyceride level

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003493.htm Triglyceride level To use the sharing features on this page, please enable JavaScript. The triglyceride level is a blood test to measure the amount ...

  19. Diagnostic Accuracy of the Slump Test for Identifying Neuropathic Pain in the Lower Limb.

    Science.gov (United States)

    Urban, Lawrence M; MacNeil, Brian J

    2015-08-01

    Diagnostic accuracy study with nonconsecutive enrollment. To assess the diagnostic accuracy of the slump test for neuropathic pain (NeP) in those with low to moderate levels of chronic low back pain (LBP), and to determine whether accuracy of the slump test improves by adding anatomical or qualitative pain descriptors. Neuropathic pain has been linked with poor outcomes, likely due to inadequate diagnosis, which precludes treatment specific for NeP. Current diagnostic approaches are time consuming or lack accuracy. A convenience sample of 21 individuals with LBP, with or without radiating leg pain, was recruited. A standardized neurosensory examination was used to determine the reference diagnosis for NeP. Afterward, the slump test was administered to all participants. Reports of pain location and quality produced during the slump test were recorded. The neurosensory examination designated 11 of the 21 participants with LBP/sciatica as having NeP. The slump test displayed high sensitivity (0.91), moderate specificity (0.70), a positive likelihood ratio of 3.03, and a negative likelihood ratio of 0.13. Adding the criterion of pain below the knee significantly increased specificity to 1.00 (positive likelihood ratio = 11.9). Pain-quality descriptors did not improve diagnostic accuracy. The slump test was highly sensitive in identifying NeP within the study sample. Adding a pain-location criterion improved specificity. Combining the diagnostic outcomes was very effective in identifying all those without NeP and half of those with NeP. Limitations arising from the small and narrow spectrum of participants with LBP/sciatica sampled within the study prevent application of the findings to a wider population. Diagnosis, level 4-.

  20. Water level detection pipeline

    International Nuclear Information System (INIS)

    Koshikawa, Yukinobu; Imanishi, Masatoshi; Niizato, Masaru; Takagi, Masahiro

    1998-01-01

    In the present invention, water levels of a feedwater heater and a drain tank in a nuclear power plant are detected at high accuracy. Detection pipeline headers connected to the upper and lower portions of a feedwater heater or a drain tank are connected with each other. The connection line is branched at appropriate two positions and an upper detection pipeline and a lower detection pipeline are connected thereto, and a gauge entrance valve is disposed to each of the detection pipelines. A diaphragm of a pressure difference generator is connected to a flange formed to the end portion. When detecting the change of water level in the feedwater heater or the drain tank as a change of pressure difference, gauge entrance valves on the exit side of the upper and lower detection pipelines are connected by a connection pipe. The gauge entrance valve is closed, a tube is connected to the lower detection pipe to inject water to the diaphragm of the pressure difference generator passing through the connection pipe thereby enabling to calibrate the pressure difference generator. The accuracy of the calibration of instruments is improved and workability thereof upon flange maintenance is also improved. (I.S.)

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

    Science.gov (United States)

    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

  2. Application of Mensuration Technology to Improve the Accuracy of Field Artillery Firing Unit Location

    Science.gov (United States)

    2013-12-13

    8 U.S. Army Field Artillery Operations ............................................................................ 8 Geodesy ...Experts in this field of study have a full working knowledge of geodesy and the theory that allows mensuration to surpass the level of accuracy achieved...desired. (2) Fire that is intended to achieve the desired result on target.”6 Geodesy : “that branch of applied mathematics which determines by observation

  3. A High-Accuracy Linear Conservative Difference Scheme for Rosenau-RLW Equation

    Directory of Open Access Journals (Sweden)

    Jinsong Hu

    2013-01-01

    Full Text Available We study the initial-boundary value problem for Rosenau-RLW equation. We propose a three-level linear finite difference scheme, which has the theoretical accuracy of Oτ2+h4. The scheme simulates two conservative properties of original problem well. The existence, uniqueness of difference solution, and a priori estimates in infinite norm are obtained. Furthermore, we analyze the convergence and stability of the scheme by energy method. At last, numerical experiments demonstrate the theoretical results.

  4. Raven’s Progressive Matrices, manipulations of complexity and measures of accuracy, speed and confidence

    OpenAIRE

    LAZAR STANKOV; KARL SCHWEIZER

    2007-01-01

    This paper examines the effects of complexity-enhancing manipulations of two cognitive tasks – Swaps and Triplet Numbers tests (Stankov, 2000) – on their relationship with Raven’s Progressive Matrices test representing aspects of fluid intelligence. The complexity manipulations involved four treatment levels, each requiring an increasing number of components and relationships among these components. The accuracy, speed of processing, and confidence measures were decomposed into experimental a...

  5. Influence of the demand information quality on planning process accuracy in supply chain. Case studies

    OpenAIRE

    Natalia Szozda; Sylwia Werbińska-Wojciechowska

    2013-01-01

    Background: Identification and analysis of factors that affect the accuracy of demand planning process across the supply chain is one of the most important problems which influence the effectiveness of its material and information flows. Material and methods: On the basis of demand planning process investigation authors define the main elements affecting the right supply chain performance level and investigate the possible connections between demand information quality and demand plannin...

  6. DOTD standards for GPS data collection accuracy : [tech summary].

    Science.gov (United States)

    2015-09-01

    Positional data collection e orts performed by personnel and contractors of the Louisiana Department of Transportation and Development : (DOTD) requires a reliable and consistent measurement framework for ensuring accuracy and precision. Global Na...

  7. The relationships between rugby ground pass accuracy and ...

    African Journals Online (AJOL)

    Kathryn van Boom

    2 Department of Physiotherapy, School of Therapeutic Sciences, Faculty of. Health Sciences ... upper body kinematics of the players, specifically the rotations of the torso and ..... relationships between the body movements and pass accuracy ...

  8. Accuracy evaluation of pendulum gravity measurements of Robert von Sterneck

    Directory of Open Access Journals (Sweden)

    Alena Pešková

    2015-06-01

    Full Text Available The accuracy of first pendulum gravity measurements in the Czech territory was determined using both original surveying notebooks of Robert Daublebsky von Sterneck and modern technologies. Since more accurate methods are used for gravity measurements nowadays, our work is mostly important from the historical point of view. In previous  works, the accuracy of Sterneck’s gravity measurements was determined using only a small dataset. Here we process all Sterneck’s measurements from the Czech territory (a dataset ten times larger than in the previous works, and we complexly assess the accuracy of these measurements. Locations of the measurements were found with the help of original notebooks. Gravity in the site was interpolated using actual gravity models. Finally, the accuracy of Sterneck’s measurements was evaluated as the difference between the measured and interpolated gravity.

  9. Evaluating clinical accuracy of continuous glucose monitoring devices: other methods

    NARCIS (Netherlands)

    Wentholt, Iris M. E.; Hart, August A.; Hoekstra, Joost B. L.; DeVries, J. Hans

    2008-01-01

    With more and more continuous glucose monitoring devices entering the market, the importance of adequate accuracy assessment grows. This review discusses pros and cons of Regression Analysis and Correlation Coefficient, Relative Difference measures, Bland Altman plot, ISO criteria, combined curve

  10. Assessment of the thematic accuracy of land cover maps

    DEFF Research Database (Denmark)

    Høhle, Joachim

    2015-01-01

    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...... 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......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...

  11. [Clinical investigation of the positioning accuracy of acute pulpitis pain].

    Science.gov (United States)

    Wang, Jin; Sun, Wei; Ji, Aiping

    2013-10-01

    This study aims to investigate the positioning accuracy of acute pulpitis pain and its possible factors. The clinical symptoms and physical signs of 3 432 cases of acute pulpitis were recorded and analyzed by using questionnaire forms, which included age, gender, tooth position, infection origin, pain history, time of acute attack, duration and nature of pain, pain frequency, referred pain areas, percussion examination, temperature pulp test, pulp bleeding, and positioning accuracy. Univariate analysis and multivariate stepwise regression analysis were used for data processing. Pain location was accurately identified by 39.1% of the patients with acute pulpitis. Referred pain could reduce the positioning accuracy of pain (P 0.05). Some cases of acute pulpitis pain can be located accurately. Referred pain and periodontium infection origin are related to the positioning accuracy of acute pulpitis pain. The exact cause of this correlation needs further study.

  12. Modified sine bar device measures small angles with high accuracy

    Science.gov (United States)

    Thekaekara, M.

    1968-01-01

    Modified sine bar device measures small angles with enough accuracy to calibrate precision optical autocollimators. The sine bar is a massive bar of steel supported by two cylindrical rods at one end and one at the other.

  13. Accuracy of Giovanni and Marksim Software Packages for ...

    African Journals Online (AJOL)

    Accuracy of Giovanni and Marksim Software Packages for Generating Daily Rainfall Data in ... using Giovanni software over Marksim, for areas receiving bimodal rainfall regimes similar to ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  14. P-Scan provides accuracy and repeatability in ultrasonics

    International Nuclear Information System (INIS)

    Keys, R.L.

    1987-01-01

    The P-Scan (Projection image scanning technique) is an automated ultrasonic inspection technique, developed to overcome the problems with accuracy and repeatability experienced with manual ultrasonic systems. The equipment and its applications are described. (author)

  15. The accuracy of time dependent transport equation ergodic approximation

    International Nuclear Information System (INIS)

    Stancic, V.

    1995-01-01

    In order to predict the accuracy of the ergodic approximation for solving the time dependent transport equation, a comparison with respect to multiple collision and time finite difference methods, has been considered. (author)

  16. Examination of the Accuracy of Coding Hospital-Acquired...

    Data.gov (United States)

    U.S. Department of Health & Human Services — A new study, Examination of the Accuracy of Coding Hospital-Acquired Pressure Ulcer Stages, published in Volume 4, Issue 1 of the Medicare and Medicaid Research...

  17. Assessing the accuracy of remote sensing techniques in vegetation ...

    African Journals Online (AJOL)

    Assessing the accuracy of remote sensing techniques in vegetation fractions estimation. ... This study aimed at exploring different remote sensing (RS) techniques for quantitatively measuring vegetation and bare soil ... HOW TO USE AJOL.

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

    Science.gov (United States)

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

    2005-11-01

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

  19. Error analysis to improve the speech recognition accuracy on ...

    Indian Academy of Sciences (India)

    dictionary plays a key role in the speech recognition accuracy. .... Sophisticated microphone is used for the recording speech corpus in a noise free environment. .... values, word error rate (WER) and error-rate will be calculated as follows:.

  20. What do we mean by accuracy in geomagnetic measurements?

    Science.gov (United States)

    Green, A.W.

    1990-01-01

    High accuracy is what distinguishes measurements made at the world's magnetic observatories from other types of geomagnetic measurements. High accuracy in determining the absolute values of the components of the Earth's magnetic field is essential to studying geomagnetic secular variation and processes at the core mantle boundary, as well as some magnetospheric processes. In some applications of geomagnetic data, precision (or resolution) of measurements may also be important. In addition to accuracy and resolution in the amplitude domain, it is necessary to consider these same quantities in the frequency and space domains. New developments in geomagnetic instruments and communications make real-time, high accuracy, global geomagnetic observatory data sets a real possibility. There is a growing realization in the scientific community of the unique relevance of geomagnetic observatory data to the principal contemporary problems in solid Earth and space physics. Together, these factors provide the promise of a 'renaissance' of the world's geomagnetic observatory system. ?? 1990.

  1. Error Estimation and Accuracy Improvements in Nodal Transport Methods

    International Nuclear Information System (INIS)

    Zamonsky, O.M.

    2000-01-01

    The accuracy of the solutions produced by the Discrete Ordinates neutron transport nodal methods is analyzed.The obtained new numerical methodologies increase the accuracy of the analyzed scheems and give a POSTERIORI error estimators. The accuracy improvement is obtained with new equations that make the numerical procedure free of truncation errors and proposing spatial reconstructions of the angular fluxes that are more accurate than those used until present. An a POSTERIORI error estimator is rigurously obtained for one dimensional systems that, in certain type of problems, allows to quantify the accuracy of the solutions. From comparisons with the one dimensional results, an a POSTERIORI error estimator is also obtained for multidimensional systems. LOCAL indicators, which quantify the spatial distribution of the errors, are obtained by the decomposition of the menctioned estimators. This makes the proposed methodology suitable to perform adaptive calculations. Some numerical examples are presented to validate the theoretical developements and to illustrate the ranges where the proposed approximations are valid

  2. Accuracy of impressions with different impression materials in ...

    African Journals Online (AJOL)

    Purpose: To evaluate the dimensional accuracy of the resultant (duplicative) casts made from two ... materials in a special tray, using a open tray impression technique from the master casts. These impressions were poured to obtain test casts.

  3. Different intensities of basketball drills affect jump shot accuracy of expert and junior players

    Directory of Open Access Journals (Sweden)

    Giuseppe Marcolin

    2018-02-01

    Full Text Available Background In basketball a maximum accuracy at every game intensity is required while shooting. The aim of the present study was to investigate the acute effect of three different drill intensity simulation protocols on jump shot accuracy in expert and junior basketball players. Materials & Methods Eleven expert players (age 26 ± 6 yrs, weight 86 ± 11 kg, height 192 ± 8 cm and ten junior players (age 18 ± 1 yrs, weight 75 ± 12 kg, height 184 ± 9 cm completed three series of twenty jump shots at three different levels of exertion. Counter Movement Jump (CMJ height was also measured after each series of jump shots. Exertion’s intensity was induced manipulating the basketball drills. Heart rate was measured for the whole duration of the tests while the rating of perceived exertion (RPE was collected at the end of each series of shots. Results Heart rate and rating of perceived exertion (RPE were statistically different in the three conditions for both expert and junior players. CMJ height remained almost unchanged in both groups. Jump shot accuracy decreased with increasing drills intensity both in experts and junior players. Expert players showed higher accuracy than junior players for all the three levels of exertion (83% vs 64%, p < 0.001; 75% vs 57%, p < 0.05; 76% vs 60%, p < 0.01. Moreover, for the most demanding level of exertion, experts showed a higher accuracy in the last ten shots compared to the first ten shots (82% vs 70%, p < 0.05. Discussion Experts coped better with the different exertion’s intensities, thus maintaining a higher level of performance. The introduction of technical short bouts of high-intensity sport-specific exercises into skill sessions should be proposed to improve jump shot accuracy during matches.

  4. 31 CFR 10.22 - Diligence as to accuracy.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Diligence as to accuracy. 10.22... § 10.22 Diligence as to accuracy. (a) In general. A practitioner must exercise due diligence— (1) In... provided in §§ 10.34, 10.35, and 10.37, a practitioner will be presumed to have exercised due diligence for...

  5. Indicators of Accuracy of Consumer Health Information on the Internet

    Science.gov (United States)

    Fallis, Don; Frické, Martin

    2002-01-01

    Objectives: To identify indicators of accuracy for consumer health information on the Internet. The results will help lay people distinguish accurate from inaccurate health information on the Internet. Design: Several popular search engines (Yahoo, AltaVista, and Google) were used to find Web pages on the treatment of fever in children. The accuracy and completeness of these Web pages was determined by comparing their content with that of an instrument developed from authoritative sources on treating fever in children. The presence on these Web pages of a number of proposed indicators of accuracy, taken from published guidelines for evaluating the quality of health information on the Internet, was noted. Main Outcome Measures: Correlation between the accuracy of Web pages on treating fever in children and the presence of proposed indicators of accuracy on these pages. Likelihood ratios for the presence (and absence) of these proposed indicators. Results: One hundred Web pages were identified and characterized as “more accurate” or “less accurate.” Three indicators correlated with accuracy: displaying the HONcode logo, having an organization domain, and displaying a copyright. Many proposed indicators taken from published guidelines did not correlate with accuracy (e.g., the author being identified and the author having medical credentials) or inaccuracy (e.g., lack of currency and advertising). Conclusions: This method provides a systematic way of identifying indicators that are correlated with the accuracy (or inaccuracy) of health information on the Internet. Three such indicators have been identified in this study. Identifying such indicators and informing the providers and consumers of health information about them would be valuable for public health care. PMID:11751805

  6. Assessing the Accuracy of Ancestral Protein Reconstruction Methods

    OpenAIRE

    Williams, Paul D; Pollock, David D; Blackburne, Benjamin P; Goldstein, Richard A

    2006-01-01

    The phylogenetic inference of ancestral protein sequences is a powerful technique for the study of molecular evolution, but any conclusions drawn from such studies are only as good as the accuracy of the reconstruction method. Every inference method leads to errors in the ancestral protein sequence, resulting in potentially misleading estimates of the ancestral protein's properties. To assess the accuracy of ancestral protein reconstruction methods, we performed computational population evolu...

  7. Technique for Increasing Accuracy of Positioning System of Machine Tools

    Directory of Open Access Journals (Sweden)

    Sh. Ji

    2014-01-01

    Full Text Available The aim of research is to improve the accuracy of positioning and processing system using a technique for optimization of pressure diagrams of guides in machine tools. The machining quality is directly related to its accuracy, which characterizes an impact degree of various errors of machines. The accuracy of the positioning system is one of the most significant machining characteristics, which allow accuracy evaluation of processed parts.The literature describes that the working area of the machine layout is rather informative to characterize the effect of the positioning system on the macro-geometry of the part surfaces to be processed. To enhance the static accuracy of the studied machine, in principle, two groups of measures are possible. One of them points toward a decrease of the cutting force component, which overturns the slider moments. Another group of measures is related to the changing sizes of the guide facets, which may lead to their profile change.The study was based on mathematical modeling and optimization of the cutting zone coordinates. And we find the formula to determine the surface pressure of the guides. The selected parameters of optimization are vectors of the cutting force and values of slides and guides. Obtained results show that a technique for optimization of coordinates in the cutting zone was necessary to increase a processing accuracy.The research has established that to define the optimal coordinates of the cutting zone we have to change the sizes of slides, value and coordinates of applied forces, reaching the pressure equalization and improving the accuracy of positioning system of machine tools. In different points of the workspace a vector of forces is applied, pressure diagrams are found, which take into account the changes in the parameters of positioning system, and the pressure diagram equalization to provide the most accuracy of machine tools is achieved.

  8. Reliability and accuracy of four dental shade-matching devices.

    Science.gov (United States)

    Kim-Pusateri, Seungyee; Brewer, Jane D; Davis, Elaine L; Wee, Alvin G

    2009-03-01

    There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (Preliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

  9. Level 1 - level 2 interface

    International Nuclear Information System (INIS)

    Boneham, P.

    2003-01-01

    The Plant Damage States (PDS) are the starting point for the level 2 analysis. A PDS is group of core damage sequences that are expected to have similar severe accident progressions. In this paper an overview of Level 1/Level 2 interface, example PDS parameters, example PDS definitions using codes and example Bridge Tree are presented. PDS frequency calculation (identification of sequences for each PDS in level 1,split some CD sequences which have different level 2 progressions), code calculations providing support for grouping decisions and timings as well as PDS frequencies and definitions input to level 2 are also discussed

  10. A Computer Navigation System Analysis of the Accuracy of the Extramedullary (Tibial Alignment Technique in Total Knee Arthroplasty (TKA

    Directory of Open Access Journals (Sweden)

    EK Chee

    2010-07-01

    Full Text Available In total knee arthroplasty, mechanical alignment guides have improved the accuracy of implant alignment, but errors are not uncommon. In the present study, an image-free computer-assisted navigation system was used to analyse the accuracy of an extramedullary (tibial alignment system, which is based on predetermined, fixed anatomical landmarks. Comparisons were made between two surgeons, with different levels of competency in order to determine if experience affected the accuracy of extramedullary tibial jig placement, in either the coronal and sagittal planes or both planes. The results showed that the accuracy of the extramedullary tibial alignment system, in the coronal plane (in up to 80-87% of cases was much better than for posterior slope, and sagittal plane. Surgeon experience was not a significant factor.

  11. Factors affecting GEBV accuracy with single-step Bayesian models.

    Science.gov (United States)

    Zhou, Lei; Mrode, Raphael; Zhang, Shengli; Zhang, Qin; Li, Bugao; Liu, Jian-Feng

    2018-01-01

    A single-step approach to obtain genomic prediction was first proposed in 2009. Many studies have investigated the components of GEBV accuracy in genomic selection. However, it is still unclear how the population structure and the relationships between training and validation populations influence GEBV accuracy in terms of single-step analysis. Here, we explored the components of GEBV accuracy in single-step Bayesian analysis with a simulation study. Three scenarios with various numbers of QTL (5, 50, and 500) were simulated. Three models were implemented to analyze the simulated data: single-step genomic best linear unbiased prediction (GBLUP; SSGBLUP), single-step BayesA (SS-BayesA), and single-step BayesB (SS-BayesB). According to our results, GEBV accuracy was influenced by the relationships between the training and validation populations more significantly for ungenotyped animals than for genotyped animals. SS-BayesA/BayesB showed an obvious advantage over SSGBLUP with the scenarios of 5 and 50 QTL. SS-BayesB model obtained the lowest accuracy with the 500 QTL in the simulation. SS-BayesA model was the most efficient and robust considering all QTL scenarios. Generally, both the relationships between training and validation populations and LD between markers and QTL contributed to GEBV accuracy in the single-step analysis, and the advantages of single-step Bayesian models were more apparent when the trait is controlled by fewer QTL.

  12. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data.

    Directory of Open Access Journals (Sweden)

    Frederik Coomans

    Full Text Available We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two 'one-process' models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a 'two-process' model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses.

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

    Science.gov (United States)

    Conradt, Larissa

    2013-12-06

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

  14. Acquisition of decision making criteria: reward rate ultimately beats accuracy.

    Science.gov (United States)

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

    2011-02-01

    Speed-accuracy trade-offs strongly influence the rate of reward that can be earned in many decision-making tasks. Previous reports suggest that human participants often adopt suboptimal speed-accuracy trade-offs in single session, two-alternative forced-choice tasks. We investigated whether humans acquired optimal speed-accuracy trade-offs when extensively trained with multiple signal qualities. When performance was characterized in terms of decision time and accuracy, our participants eventually performed nearly optimally in the case of higher signal qualities. Rather than adopting decision criteria that were individually optimal for each signal quality, participants adopted a single threshold that was nearly optimal for most signal qualities. However, setting a single threshold for different coherence conditions resulted in only negligible decrements in the maximum possible reward rate. Finally, we tested two hypotheses regarding the possible sources of suboptimal performance: (1) favoring accuracy over reward rate and (2) misestimating the reward rate due to timing uncertainty. Our findings provide support for both hypotheses, but also for the hypothesis that participants can learn to approach optimality. We find specifically that an accuracy bias dominates early performance, but diminishes greatly with practice. The residual discrepancy between optimal and observed performance can be explained by an adaptive response to uncertainty in time estimation.

  15. The Assessment of Quality, Accuracy, and Readability of Online Educational Resources for Platelet-Rich Plasma.

    Science.gov (United States)

    Ghodasra, Jason H; Wang, Dean; Jayakar, Rohit G; Jensen, Andrew R; Yamaguchi, Kent T; Hegde, Vishal V; Jones, Kristofer J

    2018-01-01

    To critically evaluate the quality, accuracy, and readability of readily available Internet patient resources for platelet-rich plasma (PRP) as a treatment modality for musculoskeletal injuries. Using the 3 most commonly used Internet search engines (Google, Bing, Yahoo), the search term "platelet rich plasma" was entered, and the first 50 websites from each search were reviewed. The website's affiliation was identified. Quality was evaluated using 25-point criteria based on guidelines published by the American Academy of Orthopaedic Surgeons, and accuracy was assessed with a previously described 12-point grading system by 3 reviewers independently. Readability was evaluated using the Flesch-Kincaid (FK) grade score. A total of 46 unique websites were identified and evaluated. The average quality and accuracy was 9.4 ± 3.4 (maximum 25) and 7.9 ± 2.3 (maximum 12), respectively. The average FK grade level was 12.6 ± 2.4, which is several grades higher than the recommended eighth-grade level for patient education material. Ninety-one percent (42/46) of websites were authored by physicians, and 9% (4/46) contained commercial bias. Mean quality was significantly greater in websites authored by health care providers (9.8 ± 3.1 vs 5.9 ± 4.7, P = .029) and in websites without commercial bias (9.9 ± 3.1 vs 4.5 ± 3.2, P = .002). Mean accuracy was significantly lower in websites authored by health care providers (7.6 ± 2.2 vs 11.0 ± 1.2, P = .004). Only 24% (11/46) reported that PRP remains an investigational treatment. The accuracy and quality of online patient resources for PRP are poor, and the information overestimates the reading ability of the general population. Websites authored by health care providers had higher quality but lower accuracy. Additionally, the majority of websites do not identify PRP as an experimental treatment, which may fail to provide appropriate patient understanding and expectations. Physicians should educate patients that many online

  16. Urban Land Cover Mapping Accuracy Assessment - A Cost-benefit Analysis Approach

    Science.gov (United States)

    Xiao, T.

    2012-12-01

    One of the most important components in urban land cover mapping is mapping accuracy assessment. Many statistical models have been developed to help design simple schemes based on both accuracy and confidence levels. It is intuitive that an increased number of samples increases the accuracy as well as the cost of an assessment. Understanding cost and sampling size is crucial in implementing efficient and effective of field data collection. Few studies have included a cost calculation component as part of the assessment. In this study, a cost-benefit sampling analysis model was created by combining sample size design and sampling cost calculation. The sampling cost included transportation cost, field data collection cost, and laboratory data analysis cost. Simple Random Sampling (SRS) and Modified Systematic Sampling (MSS) methods were used to design sample locations and to extract land cover data in ArcGIS. High resolution land cover data layers of Denver, CO and Sacramento, CA, street networks, and parcel GIS data layers were used in this study to test and verify the model. The relationship between the cost and accuracy was used to determine the effectiveness of each sample method. The results of this study can be applied to other environmental studies that require spatial sampling.

  17. Method of control of machining accuracy of low-rigidity elastic-deformable shafts

    Directory of Open Access Journals (Sweden)

    Antoni Świć

    Full Text Available The paper presents an analysis of the possibility of increasing the accuracy and stability of machining of low-rigidity shafts while ensuring high efficiency and economy of their machining. An effective way of improving the accuracy of machining of shafts is increasing their rigidity as a result of oriented change of the elastic-deformable state through the application of a tensile force which, combined with the machining force, forms longitudinal-lateral strains. The paper also presents mathematical models describing the changes of the elastic-deformable state resulting from the application of the tensile force. It presents the results of experimental studies on the deformation of elastic low-rigidity shafts, performed on a special test stand developed on the basis of a lathe. An estimation was made of the effectiveness of the method of control of the elastic-deformable state with the use, as the regulating effects, the tensile force and eccentricity. It was demonstrated that controlling the two parameters: tensile force and eccentricity, one can improve the accuracy of machining, and thus achieve a theoretically assumed level of accuracy.

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

    Science.gov (United States)

    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.

  19. Cognitive accuracy and intelligent executive function in the brain and in business.

    Science.gov (United States)

    Bailey, Charles E

    2007-11-01

    This article reviews research on cognition, language, organizational culture, brain, behavior, and evolution to posit the value of operating with a stable reference point based on cognitive accuracy and a rational bias. Drawing on rational-emotive behavioral science, social neuroscience, and cognitive organizational science on the one hand and a general model of brain and frontal lobe executive function on the other, I suggest implications for organizational success. Cognitive thought processes depend on specific brain structures functioning as effectively as possible under conditions of cognitive accuracy. However, typical cognitive processes in hierarchical business structures promote the adoption and application of subjective organizational beliefs and, thus, cognitive inaccuracies. Applying informed frontal lobe executive functioning to cognition, emotion, and organizational behavior helps minimize the negative effects of indiscriminate application of personal and cultural belief systems to business. Doing so enhances cognitive accuracy and improves communication and cooperation. Organizations operating with cognitive accuracy will tend to respond more nimbly to market pressures and achieve an overall higher level of performance and employee satisfaction.

  20. Accuracy of chest radiographs in the emergency diagnosis of heart failure

    Energy Technology Data Exchange (ETDEWEB)

    Studler, Ueli; Kretzschmar, Martin; Steinbrich, Wolfgang [University Hospital Basel, Department of Radiology, Basel (Switzerland); Christ, Michael; Breidthardt, Tobias; Noveanu, Markus; Perruchoud, Andre P.; Mueller, Christian [University Hospital Basel, Department of Internal Medicine, Basel (Switzerland); Schoetzau, Andreas [Institute of Biostatistics, Basel (Switzerland)

    2008-08-15

    The purpose of this study was to determine the diagnostic accuracy of chest radiographic findings of heart failure (HF) in current patients presenting with dyspnea in the emergency department. In a secondary analysis of the BASEL study, initial chest radiographs of 277 patients with acute dyspnea were evaluated by two radiologists blinded to the adjudicated diagnosis (56% had the final diagnosis of HF). Predefined radiographic criteria of HF were used. Statistical analysis included receiver-operating characteristic (ROC) analysis and calculation of a logistic regression model including B-type natriuretic peptide (BNP) levels. The reader's overall impression showed the highest area under the ROC curve for the diagnosis of HF in both supine and erect patient positions (0.855 and 0.857). Among individual radiographic findings, peribronchial cuffing in the supine position (0.829) showed the highest accuracies. The lowest accuracy was found for the vascular pedicle width in the supine position (0.461). Logistic regression analysis showed no significant differences between the reader's overall impression, the radiographic model, and BNP testing. In our study, the combination of radiographic features provided valuable information and was of comparable accuracy as BNP-testing for the diagnosis of HF. (orig.)

  1. Diagnostic accuracy of urinary biomarkers in infants younger than 3 months with urinary tract infection

    Science.gov (United States)

    Jung, Nani; Byun, Hye Jin; Park, Jae Hyun; Kim, Joon Sik; Kim, Hae Won

    2018-01-01

    Purpose The aim of this study was to evaluate the diagnostic accuracy of urinary biomarkers, such as neutrophil gelatinase-associated lipocalin (uNGAL) and β-2 microglobulin (uB2MG), in early detection of urinary tract infection (UTI) in infants aged UTI and non-UTI groups at the time of admission. The sensitivity, specificity, accuracy, and area under the curve (AUC) of uNGAL and uB2MG for use in diagnosing UTI were assessed. Results Among 422 patients, 102 (24.2%) were diagnosed with UTI. Levels of uNGAL were higher in the UTI group than in the non-UTI group (366.6 ng/mL vs. 26.9 ng/mL, PUTI (P=0.033). The sensitivity, specificity, and accuracy were 90.2%, 92.5%, and 91.9% for uNGAL, and 48.0%, 43.8%, and 44.8% for uB2MG, respectively. AUC of uNGAL was 0.942 and that of uB2MG was 0.407. Conclusion Accuracy of uNGAL in the diagnosis of UTI is high in febrile infants aged UTI in infants. PMID:29441109

  2. The Accuracy of Seryl-tRNA Synthesis

    Directory of Open Access Journals (Sweden)

    Ita Gruic-Sovulj

    2002-01-01

    Full Text Available The high level of translational fidelity is ensured by various types of quality control mechanisms, which are adapted to prevent or correct naturally occurring mistakes. Accurate aminoacyl-tRNA synthesis is mostly dependent on the specificity of the aminoacyl-tRNA synthetases (aaRS, i.e. their ability to choose among competing structurally similar substrates. Our studies have revealed that accurate seryl-tRNA synthesis in yeast and plants is accomplished via tRNA-assisted optimization of amino acid binding to the active site of seryl-tRNA synthetase (SerRS. Based on our recent kinetic data, a mechanism is proposed by which transient protein : RNA complex activates the cognate amino acid more efficiently and more specifically than the apoenzyme alone. This may proceed via a tRNA induced conformational change in the enzyme’s active site. The influence of tRNASer, on the activation of serine by SerRS variants mutated in the active site, is much less pronounced. Although SerRS misactivates structurally similar threonine in vitro, the formation of such erroneous threonyl-adenylate is reduced in the presence of nonchargeable tRNASer analog. Thus, the sequence-specific tRNA : SerRS interactions enhance the accuracy of amino acid recognition. Another type of quality control mechanism in tRNA serylation is assumed to be based on the complex formation between SerRS and a nonsynthetase protein. Using in vivo interaction screen, yeast peroxin Pex21p was identified as SerRS interacting protein. This was confirmed by an in vitro binding assay. Kinetic experiments performed in the presence of Pex21p revealed that this peroxin acts as an activator of seryl-tRNA synthetase in the aminoacylation reaction.

  3. THE ACCURACY AND BIAS EVALUATION OF THE USA UNEMPLOYMENT RATE FORECASTS. METHODS TO IMPROVE THE FORECASTS ACCURACY

    Directory of Open Access Journals (Sweden)

    MIHAELA BRATU (SIMIONESCU

    2012-12-01

    Full Text Available In this study some alternative forecasts for the unemployment rate of USA made by four institutions (International Monetary Fund (IMF, Organization for Economic Co-operation and Development (OECD, Congressional Budget Office (CBO and Blue Chips (BC are evaluated regarding the accuracy and the biasness. The most accurate predictions on the forecasting horizon 201-2011 were provided by IMF, followed by OECD, CBO and BC.. These results were gotten using U1 Theil’s statistic and a new method that has not been used before in literature in this context. The multi-criteria ranking was applied to make a hierarchy of the institutions regarding the accuracy and five important accuracy measures were taken into account at the same time: mean errors, mean squared error, root mean squared error, U1 and U2 statistics of Theil. The IMF, OECD and CBO predictions are unbiased. The combined forecasts of institutions’ predictions are a suitable strategy to improve the forecasts accuracy of IMF and OECD forecasts when all combination schemes are used, but INV one is the best. The filtered and smoothed original predictions based on Hodrick-Prescott filter, respectively Holt-Winters technique are a good strategy of improving only the BC expectations. The proposed strategies to improve the accuracy do not solve the problem of biasness. The assessment and improvement of forecasts accuracy have an important contribution in growing the quality of decisional process.

  4. Digital versus conventional implant impressions for partially edentulous arches: An evaluation of accuracy.

    Science.gov (United States)

    Marghalani, Amin; Weber, Hans-Peter; Finkelman, Matthew; Kudara, Yukio; El Rafie, Khaled; Papaspyridakos, Panos

    2018-04-01

    To the authors' knowledge, while accuracy outcomes of the TRIOS scanner have been compared with conventional impressions, no available data are available regarding the accuracy of digital scans with the Omnicam and True Definition scanners versus conventional impressions for partially edentulous arches. The purpose of this in vitro study was to compare the accuracy of digital implant scans using 2 different intraoral scanners (IOSs) with that of conventional impressions for partially edentulous arches. Two partially edentulous mandibular casts with 2 implant analogs with a 30-degree angulation from 2 different implant systems (Replace Select RP; Nobel Biocare and Tissue level RN; Straumann) were used as controls. Sixty digital models were made from these 2 definitive casts in 6 different groups (n=10). Splinted implant-level impression procedures followed by digitization were used to produce the first 2 groups. The next 2 groups were produced by digital scanning with Omnicam. The last 2 groups were produced by digital scanning with the True Definition scanner. Accuracy was evaluated by superimposing the digital files of each test group onto the digital file of the controls with inspection software. The difference in 3-dimensional (3D) deviations (median ±interquartile range) among the 3 impression groups for Nobel Biocare was statistically significant among all groups (P3D deviations among the 3 impression groups for Straumann was statistically significant among all groups (P=.003), except for the conventional impression (22 ±5 μm) and True Definition (17 ±5 μm) groups; the median ±interquartile range for the Omnicam group was 26 ±15 μm. The difference in 3D deviations between the 2 implant systems was significant for the Omnicam (P=.011) and conventional (Pimpression techniques but not for the True Definition technique (P=.247). Within the limitations of this study, both the impression technique and the implant system affected accuracy. The True

  5. Effect of Kinesiotape Applications on Ball Velocity and Accuracy in Amateur Soccer and Handball.

    Science.gov (United States)

    Müller, Carsten; Brandes, Mirko

    2015-12-22

    Evidence supporting performance enhancing effects of kinesiotape in sports is missing. The aims of this study were to evaluate effects of kinesiotape applications with regard to shooting and throwing performance in 26 amateur soccer and 32 handball players, and to further investigate if these effects were influenced by the players' level of performance. Ball speed as the primary outcome and accuracy of soccer kicks and handball throws were analyzed with and without kinesiotape by means of radar units and video recordings. The application of kinesiotapes significantly increased ball speed in soccer by 1.4 km/h (p=0.047) and accuracy with a lesser distance from the target by -6.9 cm (p=0.039). Ball velocity in handball throws also significantly increased by 1.2 km/h (p=0.013), while accuracy was deteriorated with a greater distance from the target by 3.4 cm (p=0.005). Larger effects with respect to ball speed were found in players with a lower performance level in kicking (1.7 km/h, p=0.028) and throwing (1.8 km/h, p=0.001) compared with higher level soccer and handball players (1.2 km/h, p=0.346 and 0.5 km/h, p=0.511, respectively). In conclusion, the applications of kinesiotape used in this study might have beneficial effects on performance in amateur soccer, but the gain in ball speed in handball is counteracted by a significant deterioration of accuracy. Subgroup analyses indicate that kinesiotape may yield larger effects on ball velocity in athletes with lower kicking and throwing skills.

  6. Accuracy and coverage of the modernized Polish Maritime differential GPS system

    Science.gov (United States)

    Specht, Cezary

    2011-01-01

    The DGPS navigation service augments The NAVSTAR Global Positioning System by providing localized pseudorange correction factors and ancillary information which are broadcast over selected marine reference stations. The DGPS service position and integrity information satisfy requirements in coastal navigation and hydrographic surveys. Polish Maritime DGPS system has been established in 1994 and modernized (in 2009) to meet the requirements set out in IMO resolution for a future GNSS, but also to preserve backward signal compatibility of user equipment. Having finalized installation of the new technology L1, L2 reference equipment performance tests were performed.The paper presents results of the coverage modeling and accuracy measuring campaign based on long-term signal analyses of the DGPS reference station Rozewie, which was performed for 26 days in July 2009. Final results allowed to verify the coverage area of the differential signal from reference station and calculated repeatable and absolute accuracy of the system, after the technical modernization. Obtained field strength level area and position statistics (215,000 fixes) were compared to past measurements performed in 2002 (coverage) and 2005 (accuracy), when previous system infrastructure was in operation.So far, no campaigns were performed on differential Galileo. However, as signals, signal processing and receiver techniques are comparable to those know from DGPS. Because all satellite differential GNSS systems use the same transmission standard (RTCM), maritime DGPS Radiobeacons are standardized in all radio communication aspects (frequency, binary rate, modulation), then the accuracy results of differential Galileo can be expected as a similar to DGPS.Coverage of the reference station was calculated based on unique software, which calculate the signal strength level based on transmitter parameters or field signal strength measurement campaign, done in the representative points. The software works

  7. Accuracy of magnetic resonance in identifying traumatic intraarticular knee lesions

    International Nuclear Information System (INIS)

    Vaz, Carlos Eduardo Sanches; Camargo, Olavo Pires de; Santana, Paulo Jose de; Valezi, Antonio Carlos

    2005-01-01

    Purpose: To evaluate the diagnostic accuracy of magnetic resonance imaging of the knee in identifying traumatic intraarticular knee lesions. Method: 300 patients with a clinical diagnosis of traumatic intraarticular knee lesions underwent prearthoscopic magnetic resonance imaging. The sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for a positive test, likelihood ratio for a negative test, and accuracy of magnetic resonance imaging were calculated relative to the findings during arthroscopy in the studied structures of the knee (medial meniscus, lateral meniscus, anterior cruciate ligament, posterior cruciate ligament, and articular cartilage). Results: Magnetic resonance imaging produced the following results regarding detection of lesions: medial meniscus: sensitivity 97.5%, specificity 92.9%, positive predictive value 93.9%, positive negative value 97%, likelihood positive ratio 13.7, likelihood negative ratio 0.02, and accuracy 95.3%; lateral meniscus: sensitivity 91.9%, specificity 93.6%, positive predictive value 92.7%, positive negative value 92.9%, likelihood positive ratio 14.3, likelihood negative ratio 0.08, and accuracy 93.6%; anterior cruciate ligament: sensitivity 99.0%, specificity 95.9%, positive predictive value 91.9%, positive negative value 99.5%, likelihood positive ratio 21.5, likelihood negative ratio 0.01, and accuracy 96.6%; posterior cruciate ligament: sensitivity 100%, specificity 99%, positive predictive value 80.0%, positive negative value 100%, likelihood positive ratio 100, likelihood negative ratio 0.01, and accuracy 99.6%; articular cartilage: sensitivity 76.1%, specificity 94.9%, positive predictive value 94.7%, positive negative value 76.9%, likelihood positive ratio 14.9, likelihood negative ratio 0.25, and accuracy 84.6%. Conclusion: Magnetic resonance imaging is a satisfactory diagnostic tool for evaluating meniscal and ligamentous lesions of the knee, but it is unable to clearly

  8. Accuracy of magnetic resonance in identifying traumatic intraarticular knee lesions

    Directory of Open Access Journals (Sweden)

    Vaz Carlos Eduardo Sanches

    2005-01-01

    Full Text Available PURPOSE: To evaluate the diagnostic accuracy of magnetic resonance imaging of the knee in identifying traumatic intraarticular knee lesions. METHOD: 300 patients with a clinical diagnosis of traumatic intraarticular knee lesions underwent prearthoscopic magnetic resonance imaging. The sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for a positive test, likelihood ratio for a negative test, and accuracy of magnetic resonance imaging were calculated relative to the findings during arthroscopy in the studied structures of the knee (medial meniscus, lateral meniscus, anterior cruciate ligament, posterior cruciate ligament, and articular cartilage. RESULTS: Magnetic resonance imaging produced the following results regarding detection of lesions: medial meniscus: sensitivity 97.5%, specificity 92.9%, positive predictive value 93.9%, positive negative value 97%, likelihood positive ratio 13.7, likelihood negative ratio 0.02, and accuracy 95.3%; lateral meniscus: sensitivity 91.9%, specificity 93.6%, positive predictive value 92.7%, positive negative value 92.9%, likelihood positive ratio 14.3, likelihood negative ratio 0.08, and accuracy 93.6%; anterior cruciate ligament: sensitivity 99.0%, specificity 95.9%, positive predictive value 91.9%, positive negative value 99.5%, likelihood positive ratio 21.5, likelihood negative ratio 0.01, and accuracy 96.6%; posterior cruciate ligament: sensitivity 100%, specificity 99%, positive predictive value 80.0%, positive negative value 100%, likelihood positive ratio 100, likelihood negative ratio 0.01, and accuracy 99.6%; articular cartilage: sensitivity 76.1%, specificity 94.9%, positive predictive value 94.7%, positive negative value 76.9%, likelihood positive ratio 14.9, likelihood negative ratio 0.25, and accuracy 84.6%. CONCLUSION: Magnetic resonance imaging is a satisfactory diagnostic tool for evaluating meniscal and ligamentous lesions of the knee, but it is

  9. Speed and accuracy of visual image discrimination by rats

    Directory of Open Access Journals (Sweden)

    Pamela eReinagel

    2013-12-01

    Full Text Available The trade-off between speed and accuracy of sensory discrimination has most often been studying 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, 2-alternative forced-choice (2AFC 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 two to six seconds. 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

  10. Wind power forecasting accuracy and uncertainty in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H.; Miettinen, J.; Sillanpaeae, S.

    2013-04-15

    Wind power cannot be dispatched so the production levels need to be forecasted for electricity market trading. Lower prediction errors mean lower regulation balancing costs, since relatively less energy needs to go through balance settlement. From the power system operator point of view, wind power forecast errors will impact the system net imbalances when the share of wind power increases, and more accurate forecasts mean less regulating capacity will be activated from the real time Regulating Power Market. In this publication short term forecasting of wind power is studied mainly from a wind power producer point of view. The forecast errors and imbalance costs from the day-ahead Nordic electricity markets are calculated based on real data from distributed wind power plants. Improvements to forecasting accuracy are presented using several wind forecast providers, and measures for uncertainty of the forecast are presented. Aggregation of sites lowers relative share of prediction errors considerably, up to 60%. The balancing costs were also reduced up to 60%, from 3 euro/MWh for one site to 1-1.4 euro/MWh to aggregate 24 sites. Pooling wind power production for balance settlement will be very beneficial, and larger producers who can have sites from larger geographical area will benefit in lower imbalance costs. The aggregation benefits were already significant for smaller areas, resulting in 30-40% decrease in forecast errors and 13-36% decrease in unit balancing costs, depending on the year. The resulting costs are strongly dependent on Regulating Market prices that determine the prices for the imbalances. Similar level of forecast errors resulted in 40% higher imbalance costs for 2012 compared with 2011. Combining wind forecasts from different Numerical Weather Prediction providers was studied with different combination methods for 6 sites. Averaging different providers' forecasts will lower the forecast errors by 6% for day-ahead purposes. When combining

  11. Accuracy in HIV Rapid Testing among Laboratory and Non-laboratory Personnel in Zambia: Observations from the National HIV Proficiency Testing System.

    Directory of Open Access Journals (Sweden)

    Sheila Mwangala

    Full Text Available Despite rapid task-shifting and scale-up of HIV testing services in high HIV prevalence countries, studies evaluating accuracy remain limited. This study aimed to assess overall accuracy level and factors associated with accuracy in HIV rapid testing in Zambia.Accuracy was investigated among rural and urban HIV testing sites participating in two annual national HIV proficiency testing (PT exercises conducted in 2009 (n = 282 sites and 2010 (n = 488 sites. Testers included lay counselors, nurses, laboratory personnel and others. PT panels of five dry tube specimens (DTS were issued to testing sites by the national reference laboratory (NRL. Site accuracy level was assessed by comparison of reported results to the expected results. Non-parametric rank tests and multiple linear regression models were used to assess variation in accuracy between PT cycles and between tester groups, and to examine factors associated with accuracy respectively.Overall accuracy level was 93.1% (95% CI: 91.2-94.9 in 2009 and 96.9% (95% CI: 96.1-97.8 in 2010. Differences in accuracy were seen between the tester groups in 2009 with laboratory personnel being more accurate than non-laboratory personnel, while in 2010 no differences were seen. In both PT exercises, lay counselors and nurses had more difficulties interpreting results, with more occurrences of false-negative, false-positive and indeterminate results. Having received the standard HIV rapid testing training and adherence to the national HIV testing algorithm were positively associated with accuracy.The study showed an improvement in tester group and overall accuracy from the first PT exercise to the next. Average number of incorrect test results per 1000 tests performed was reduced from 69 to 31. Further improvement is needed, however, and the national HIV proficiency testing system seems to be an important tool in this regard, which should be continued and needs to be urgently strengthened.

  12. Level densities

    International Nuclear Information System (INIS)

    Ignatyuk, A.V.

    1998-01-01

    For any applications of the statistical theory of nuclear reactions it is very important to obtain the parameters of the level density description from the reliable experimental data. The cumulative numbers of low-lying levels and the average spacings between neutron resonances are usually used as such data. The level density parameters fitted to such data are compiled in the RIPL Starter File for the tree models most frequently used in practical calculations: i) For the Gilber-Cameron model the parameters of the Beijing group, based on a rather recent compilations of the neutron resonance and low-lying level densities and included into the beijing-gc.dat file, are chosen as recommended. As alternative versions the parameters provided by other groups are given into the files: jaeri-gc.dat, bombay-gc.dat, obninsk-gc.dat. Additionally the iljinov-gc.dat, and mengoni-gc.dat files include sets of the level density parameters that take into account the damping of shell effects at high energies. ii) For the backed-shifted Fermi gas model the beijing-bs.dat file is selected as the recommended one. Alternative parameters of the Obninsk group are given in the obninsk-bs.dat file and those of Bombay in bombay-bs.dat. iii) For the generalized superfluid model the Obninsk group parameters included into the obninsk-bcs.dat file are chosen as recommended ones and the beijing-bcs.dat file is included as an alternative set of parameters. iv) For the microscopic approach to the level densities the files are: obninsk-micro.for -FORTRAN 77 source for the microscopical statistical level density code developed in Obninsk by Ignatyuk and coworkers, moller-levels.gz - Moeller single-particle level and ground state deformation data base, moller-levels.for -retrieval code for Moeller single-particle level scheme. (author)

  13. Comparative Dose Accuracy of Durable and Patch Insulin Infusion Pumps

    Science.gov (United States)

    Jahn, Luis G.; Capurro, Jorge J.; Levy, Brian L.

    2013-01-01

    Background: As all major insulin pump manufacturers comply with the international infusion pump standard EN 60601-2-24:1998, there may be a general assumption that all pumps are equal in insulin-delivery accuracy. This research investigates single-dose and averaged-dose accuracy of incremental basal deliveries for one patch model and three durable models of insulin pumps. Method: For each pump model, discrete single doses delivered during 0.5 U/h basal rate infusion over a 20 h period were measured using a time-stamped microgravimetric system. Dose accuracy was analyzed by comparing single doses and time-averaged doses to specific accuracy thresholds (±5% to ±30%). Results: The percentage of single doses delivered outside accuracy thresholds of ±5%, ±10%, and ±20% were as follows: Animas OneTouch® Ping® (43.2%, 14.3%, and 1.8%, respectively), Roche Accu-Chek® Combo (50.6%, 24.4%, and 5.5%), Medtronic Paradigm® RevelTM/VeoTM (54.2%, 26.7%, and 6.6%), and Insulet OmniPod® (79.1%, 60.5%, and 34.9%). For 30 min, 1 h, and 2 h averaging windows, the percentage of doses delivered outside a ±15% accuracy were as follows: OneTouch Ping (1.0%, 0.4%, and 0%, respectively), Accu-Chek Combo (4.2%, 3.5%, and 3.1%), Paradigm Revel/Veo (3.9%, 3.1%, and 2.2%), and OmniPod (33.9%, 19.9%, and 10.3%). Conclusions: This technical evaluation demonstrates significant differences in single-dose and averaged-dose accuracy among the insulin pumps tested. Differences in dose accuracy were most evident between the patch pump model and the group of durable pump models. Of the pumps studied, the Animas OneTouch Ping demonstrated the best single-dose and averaged-dose accuracy. Further research on the clinical relevance of these findings is warranted. PMID:23911184

  14. Diagnostic accuracy of surgeons and trainees in assessment of patients with acute abdominal pain.

    Science.gov (United States)

    2016-09-01

    Diagnostic accuracy in the assessment of patients with acute abdominal pain in the emergency ward is not adequate. It has been argued that this is because the investigations are carried out predominantly by a trainee. Resource utilization could be lowered if surgeons had a higher initial diagnostic accuracy. Patients with acute abdominal pain were included in a prospective cohort study. A surgical trainee and a surgeon made independent assessments in the emergency department, recording the clinical diagnosis and proposed diagnostic investigations. A reference standard diagnosis was established by an expert panel, and the proportion of correct diagnoses was calculated. Diagnostic accuracy was expressed in terms of sensitivity, specificity, positive predictive value and negative predictive value. Interobserver agreement for the diagnosis and elements of history-taking and physical examination were expressed by means of Cohen's κ. Certainty of diagnosis was recorded using a visual analogue scale. A trainee and a surgeon independently assessed 126 patients. Trainees made a correct diagnosis in 44·4 per cent of patients and surgeons in 42·9 per cent (P = 0·839). Surgeons, however, recorded a higher level of diagnostic certainty. Diagnostic accuracy was comparable in distinguishing urgent from non-urgent diagnoses, and for the most common diseases. Interobserver agreement for the clinical diagnosis varied from fair to moderate (κ = 0·28-0·57). The diagnostic accuracy of the initial clinical assessment is not improved when a surgeon rather than a surgical trainee assesses a patient with abdominal pain in the emergency department. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

  15. Knowing right from wrong in mental arithmetic judgments: calibration of confidence predicts the development of accuracy.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Malinowski Marcin

    2016-12-01

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

  17. Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients

    International Nuclear Information System (INIS)

    Iyengar, S.S.; Morgan-Hughes, G.; Ukoumunne, O.; Clayton, B.; Davies, E.J.; Nikolaou, V.; Hyde, C.J.; Shore, A.C.; Roobottom, C.A.

    2016-01-01

    Aim: To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). Materials and methods: Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥50%) stenosis and secondarily as the presence of severe (≥70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. Results: No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. Conclusion: The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role. - Highlights: • Diagnostic accuracy of High-Definition CT Angiography (HD-CTCA) has been assessed. • Invasive Coronary angiography (ICA) is the reference standard. • Diagnostic accuracy of HD-CTCA is comparable to ICA. • Diagnostic accuracy is not affected by coronary calcium or stents. • HD-CTCA provides a non-invasive alternative in high-risk patients.

  18. Accuracy of a wireless localization system for radiotherapy

    International Nuclear Information System (INIS)

    Balter, James M.; Wright, J. Nelson; Newell, Laurence J.; Friemel, Barry; Dimmer, Steven; Cheng, Yuki; Wong, John; Vertatschitsch, Edward; Mate, Timothy P.

    2005-01-01

    Purpose: A system has been developed for patient positioning based on real-time localization of implanted electromagnetic transponders (beacons). This study demonstrated the accuracy of the system before clinical trials. Methods and materials: We describe the overall system. The localization component consists of beacons and a source array. A rigid phantom was constructed to place the beacons at known offsets from a localization array. Tests were performed at distances of 80 and 270 mm from the array and at positions in the array plane of up to 8 cm offset. Tests were performed in air and saline to assess the effect of tissue conductivity and with multiple transponders to evaluate crosstalk. Tracking was tested using a dynamic phantom creating a circular path at varying speeds. Results: Submillimeter accuracy was maintained throughout all experiments. Precision was greater proximal to the source plane (σx = 0.006 mm, σy = 0.01 mm, σz = 0.006 mm), but continued to be submillimeter at the end of the designed tracking range at 270 mm from the array (σx = 0.27 mm, σy = 0.36 mm, σz = 0.48 mm). The introduction of saline and the use of multiple beacons did not affect accuracy. Submillimeter accuracy was maintained using the dynamic phantom at speeds of up to 3 cm/s. Conclusion: This system has demonstrated the accuracy needed for localization and monitoring of position during treatment

  19. Martial arts striking hand peak acceleration, accuracy and consistency.

    Science.gov (United States)

    Neto, Osmar Pinto; Marzullo, Ana Carolina De Miranda; Bolander, Richard P; Bir, Cynthia A

    2013-01-01

    The goal of this paper was to investigate the possible trade-off between peak hand acceleration and accuracy and consistency of hand strikes performed by martial artists of different training experiences. Ten male martial artists with training experience ranging from one to nine years volunteered to participate in the experiment. Each participant performed 12 maximum effort goal-directed strikes. Hand acceleration during the strikes was obtained using a tri-axial accelerometer block. A pressure sensor matrix was used to determine the accuracy and consistency of the strikes. Accuracy was estimated by the radial distance between the centroid of each subject's 12 strikes and the target, whereas consistency was estimated by the square root of the 12 strikes mean squared distance from their centroid. We found that training experience was significantly correlated to hand peak acceleration prior to impact (r(2)=0.456, p =0.032) and accuracy (r(2)=0. 621, p=0.012). These correlations suggest that more experienced participants exhibited higher hand peak accelerations and at the same time were more accurate. Training experience, however, was not correlated to consistency (r(2)=0.085, p=0.413). Overall, our results suggest that martial arts training may lead practitioners to achieve higher striking hand accelerations with better accuracy and no change in striking consistency.

  20. Accuracy of pedicle screw placement in patients with Marfan syndrome.

    Science.gov (United States)

    Qiao, Jun; Zhu, Feng; Xu, Leilei; Liu, Zhen; Sun, Xu; Qian, Bangping; Jiang, Qing; Zhu, Zezhang; Qiu, Yong

    2017-03-21

    There is no study concerning safety and accuracy of pedicle screw placement in Marfan syndrome. The objective of this study is to investigate accuracy and safety of pedicle screw placement in scoliosis associated with Marfan syndrome. CT scanning was performed to analyze accuracy of pedicle screw placement. Pedicle perforations were classified as medial, lateral or anterior and categorized to four grades: ≤ 2 mm as Grade 1, 2.1-4.0 mm as Grade 2, 4.1-6.0 mm as Grade 3, ≥6.1 mm as Grade 4. Fully contained screws or with medial wall perforation ≤ 2 mm or with lateral wall perforation ≤ 6 mm and without injury of visceral organs were considered acceptable, otherwise were unacceptable. 976 pedicle screws were placed, 713 screws (73.1%) were fully contained within the cortical boundaries of the pedicle. 924 (94.7%) screws were considered as acceptable, and 52 (5.3%) as unacceptable. The perforation rate was higher using free-hand technique than O-arm navigation technique (30.8% VS. 11.4%, P Marfan syndrome is accuracy and safe. O-arm navigation was an effective modality to ensure the safety and accuracy of screw placement. Special attention should be paid when screws were placed at the lumber spine and the concave side of spine deformity to avoid the higher rate of complications.

  1. Accuracy of rainfall measurement for scales of hydrological interest

    Directory of Open Access Journals (Sweden)

    S. J. Wood

    2000-01-01

    Full Text Available The dense network of 49 raingauges over the 135 km2 Brue catchment in Somerset, England is used to examine the accuracy of rainfall estimates obtained from raingauges and from weather radar. Methods for data quality control and classification of precipitation types are first described. A super-dense network comprising eight gauges within a 2 km grid square is employed to obtain a 'true value' of rainfall against which the 2 km radar grid and a single 'typical gauge' estimate can be compared. Accuracy is assessed as a function of rainfall intensity, for different periods of time-integration (15 minutes, 1 hour and 1 day and for two 8-gauge networks in areas of low and high relief. In a similar way, the catchment gauge network is used to provide the 'true catchment rainfall' and the accuracy of a radar estimate (an area-weighted average of radar pixel values and a single 'typical gauge' estimate of catchment rainfall evaluated as a function of rainfall intensity. A single gauge gives a standard error of estimate for rainfall in a 2 km square and over the catchment of 33% and 65% respectively, at rain rates of 4 mm in 15 minutes. Radar data at 2 km resolution give corresponding errors of 50% and 55%. This illustrates the benefit of using radar when estimating catchment scale rainfall. A companion paper (Wood et al., 2000 considers the accuracy of rainfall estimates obtained using raingauge and radar in combination. Keywords: rainfall, accuracy, raingauge, radar

  2. Evidence for enhanced interoceptive accuracy in professional musicians

    Directory of Open Access Journals (Sweden)

    Katharina eSchirmer-Mokwa

    2015-12-01

    Full Text Available 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.

  3. Evaluating arguments during instigations of defence motivation and accuracy motivation.

    Science.gov (United States)

    Liu, Cheng-Hong

    2017-05-01

    When people evaluate the strength of an argument, their motivations are likely to influence the evaluation. However, few studies have specifically investigated the influences of motivational factors on argument evaluation. This study examined the effects of defence and accuracy motivations on argument evaluation. According to the compatibility between the advocated positions of arguments and participants' prior beliefs and the objective strength of arguments, participants evaluated four types of arguments: compatible-strong, compatible-weak, incompatible-strong, and incompatible-weak arguments. Experiment 1 revealed that participants possessing a high defence motivation rated compatible-weak arguments as stronger and incompatible-strong ones as weaker than participants possessing a low defence motivation. However, the strength ratings between the high and low defence groups regarding both compatible-strong and incompatible-weak arguments were similar. Experiment 2 revealed that when participants possessed a high accuracy motivation, they rated compatible-weak arguments as weaker and incompatible-strong ones as stronger than when they possessed a low accuracy motivation. However, participants' ratings on both compatible-strong and incompatible-weak arguments were similar when comparing high and low accuracy conditions. The results suggest that defence and accuracy motivations are two major motives influencing argument evaluation. However, they primarily influence the evaluation results for compatible-weak and incompatible-strong arguments, but not for compatible-strong and incompatible-weak arguments. © 2016 The British Psychological Society.

  4. Speed and accuracy of visual motion discrimination by rats.

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    Pamela Reinagel

    Full Text Available Animals must continuously evaluate sensory information to select the preferable among possible actions in a given context, including the option to wait for more information before committing to another course of action. In experimental sensory decision tasks that replicate these features, reaction time distributions can be informative about the implicit rules by which animals determine when to commit and what to do. We measured reaction times of Long-Evans rats discriminating the direction of motion in a coherent random dot motion stimulus, using a self-paced two-alternative forced-choice (2-AFC reaction time task. Our main findings are: (1 When motion strength was constant across trials, the error trials had shorter reaction times than correct trials; in other words, accuracy increased with response latency. (2 When motion strength was varied in randomly interleaved trials, accuracy increased with motion strength, whereas reaction time decreased. (3 Accuracy increased with reaction time for each motion strength considered separately, and in the interleaved motion strength experiment overall. (4 When stimulus duration was limited, accuracy improved with stimulus duration, whereas reaction time decreased. (5 Accuracy decreased with response latency after stimulus offset. This was the case for each stimulus duration considered separately, and in the interleaved duration experiment overall. We conclude that rats integrate visual evidence over time, but in this task the time of their response is governed more by elapsed time than by a criterion for sufficient evidence.

  5. Compact Intraoperative MRI: Stereotactic Accuracy and Future Directions.

    Science.gov (United States)

    Markowitz, Daniel; Lin, Dishen; Salas, Sussan; Kohn, Nina; Schulder, Michael

    2017-01-01

    Intraoperative imaging must supply data that can be used for accurate stereotactic navigation. This information should be at least as accurate as that acquired from diagnostic imagers. The aim of this study was to compare the stereotactic accuracy of an updated compact intraoperative MRI (iMRI) device based on a 0.15-T magnet to standard surgical navigation on a 1.5-T diagnostic scan MRI and to navigation with an earlier model of the same system. The accuracy of each system was assessed using a water-filled phantom model of the brain. Data collected with the new system were compared to those obtained in a previous study assessing the older system. The accuracy of the new iMRI was measured against standard surgical navigation on a 1.5-T MRI using T1-weighted (W) images. The mean error with the iMRI using T1W images was lower than that based on images from the 1.5-T scan (1.24 vs. 2.43 mm). T2W images from the newer iMRI yielded a lower navigation error than those acquired with the prior model (1.28 vs. 3.15 mm). Improvements in magnet design can yield progressive increases in accuracy, validating the concept of compact, low-field iMRI. Avoiding the need for registration between image and surgical space increases navigation accuracy. © 2017 S. Karger AG, Basel.

  6. Accuracy of references and quotations in veterinary journals.

    Science.gov (United States)

    Hinchcliff, K W; Bruce, N J; Powers, J D; Kipp, M L

    1993-02-01

    The accuracy of references and quotations used to substantiate statements of fact in articles published in 6 frequently cited veterinary journals was examined. Three hundred references were randomly selected, and the accuracy of each citation was examined. A subset of 100 references was examined for quotational accuracy; ie, the accuracy with which authors represented the work or assertions of the author being cited. Of the 300 references selected, 295 were located, and 125 major errors were found in 88 (29.8%) of them. Sixty-seven (53.6%) major errors were found involving authors, 12 (9.6%) involved the article title, 14 (11.2%) involved the book or journal title, and 32 (25.6%) involved the volume number, date, or page numbers. Sixty-eight minor errors were detected. The accuracy of 111 quotations from 95 citations in 65 articles was examined. Nine quotations were technical and not classified, 86 (84.3%) were classified as correct, 2 (1.9%) contained minor misquotations, and 14 (13.7%) contained major misquotations. We concluded that misquotations and errors in citations occur frequently in veterinary journals, but at a rate similar to that reported for other biomedical journals.

  7. The accuracy of serum galactomannan assay in diagnosing invasive pulmonary aspergillosis.

    Science.gov (United States)

    Sarrafzadeh, Shokooh Azam; Hoseinpoor Rafati, Ali; Ardalan, Maryam; Mansouri, Davood; Tabarsi, Payam; Pourpak, Zahra

    2010-09-01

    Galactomannan (GM) antigen is an aspergillus specific antigen that is released during the growth phase of invasive aspergillosis. We aimed to find the optimum cutoff and accuracy of serum Galactomannan assay in immunocompromised patients. Immunocompromised patients diagnosed with invasive pulmonary aspergillosis (IPA) based on the European Organization for Research and Treatment of Cancer/Invasive Mycosis Study Group (EORTC/MSG) with three levels of certainty proven, probable and possible, referred for GM antigen measurement at Immunology, Asthma and Allergy Research Institute (IAARI) from 2006 to 2009 and if they met the criteria were enrolled in this study. Totally 49 patients with IPA were enrolled in our study. According to EORTC/MSG, patients categorized into three levels of certainty: They were diagnosed as 'proven' invasive pulmonary aspergillosis 16(32.7%), 'probable' 18(36.7%) and 'possible' 15(30.6%). The most common host risk factor was solid tumors 17(34.7%). The accuracy of Galactomannan assay increased from 0.5 to 2 cutoffs. The optimum sensitivity and specificity obtained at the index cutoff of ≥1.5 for diagnosis of "proven" IPA; which were respectively, 69.2% and 72.2%. Other cutoffs had high variance between sensitivity and specificity for diagnosis of IPA. The calculated cutoff gained by receiver operating characteristic (ROC) analysis for detecting proven IPA was 1.5. Intermediate accuracy of serum GM test in conjunct with clinical findings would help early IPA detection among immunocompromised patients.

  8. Personal noise dosimeters: Accuracy and reliability in varied settings

    Directory of Open Access Journals (Sweden)

    Sheri Lynn Cook-Cunningham

    2014-01-01

    Full Text Available This study investigated the accuracy, reliability, and characteristics of three brands of personal noise dosimeters (N = 7 units in both pink noise (PN environments and natural environments (NEs through the acquisition of decibel readings, Leq readings and noise doses. Acquisition periods included repeated PN conditions, choir room rehearsals and participant (N = 3 Leq and noise dosages procured during a day in the life of a music student. Among primary results: (a All dosimeters exhibited very strong positive correlations for PN measurements across all instruments; (b all dosimeters were within the recommended American National Standard Institute (ANSI SI.25-1991 standard of ±2 dB (A of a reference measurement; and (c all dosimeters were within the recommended ANSI SI.25-1991 standard of ±2 dB (A when compared with each other. Results were discussed in terms of using personal noise dosimeters within hearing conservation and research contexts and recommendations for future research. Personal noise dosimeters were studied within the contexts of PN environments and NEs (choral classroom and the day in the life of collegiate music students. This quantitative study was a non-experimental correlation design. Three brands of personal noise dosimeters (Cirrus doseBadge, Quest Edge Eg5 and Etymotic ER200D were tested in two environments, a PN setting and a natural setting. There were two conditions within each environment. In the PN environment condition one, each dosimeter was tested individually in comparison with two reference measuring devices (Ivie and Easera while PN was generated by a Whites Instrument PN Tube. In condition two, the PN procedures were replicated for longer periods while all dosimeters measured the sound levels simultaneously. In the NE condition one, all dosimeters were placed side by side on a music stand and recorded sound levels of choir rehearsals over a 7-h rehearsal period. In NE, condition two noise levels were measured

  9. Diagnostic accuracy of mammography readers and their memory performance have no correlation with each other

    International Nuclear Information System (INIS)

    Kok, P.; Cawson, J.N.; Mercuri, V.; Pitman, A.G.; Gledhill, S.; Shnier, D.; Taft, R.; Zentner, L.

    2010-01-01

    Full text: The study aims to determine if any association exists between visual memory performance and diagnostic accuracy performance in a group of radiologist mammogram readers. Materials and Methods: One hundred proven mammograms (23 with cancers) were grouped into 5 sets of 20 cases, with sets being of equal difficulty. Pairs of sets were presented in 5 reads (40 cases per read, order random) to a panel of 8 radiologist readers (either present or past screening readers, with experience range from 20 years). The readers were asked to either 'clear' or 'call back' cases depending on need for further workup, and at post-baseline reads to indicate whether each case was 'new' or 'old' (i .e. remembered from prior read). Two sets were presented only at baseline (40 cases per reader), and were used to calculate the reader's false recollection rate. Three sets were repeated post-baseline once or twice (100 cases per reader). Reading conditions were standardised. Results: Memory performance differed markedly between readers. The number of correctly remembered cases (of 100 'old' cases) had a median of 10.5 and range of 0-58. The observed number of false recollections (of 40 'totally new' cases) had a median of 2 and range of 0-17. Diagnostic performance measures were mean (range): sensitivity 0.68 (0.54-0.81); specificity 0.82 (0.74-0.91); positive predictive value (PPV) 0.55 (0.500.65); negative predictive value (NPV) 0.89 (0.86-0.93) and accuracy 0.78 (0.76-0.83). Confidence intervals (CIs; 95%) for each reader overlapped for all the diagnostic parameters, indicating a lack of statistically significant difference between the readers at the 5% level. The most sensitive and the most specific reader showed a trend away from each other on sensitivity, specificity, NPV and PPV; their accuracies were 0.76 and 0.82, respectively, and their accuracy 95% CIs overlapped considerably. Correlation analysis by reader showed no association between observed memory performance and

  10. Diagnostic accuracy of magnetic resonance imaging versus computed tomography in stress fractures of the lumbar spine

    International Nuclear Information System (INIS)

    Ganiyusufoglu, A.K.; Onat, L.; Karatoprak, O.; Enercan, M.; Hamzaoglu, A.

    2010-01-01

    Aim: To compare the diagnostic accuracy of magnetic resonance imaging (MRI) with computed tomography (CT) in stress fractures of the lumbar spine. Materials and methods: Radiological and clinical data from 57 adolescents and young adults with a diagnosis of stress injury of the lumbar spine were retrospectively reviewed. All cases had undergone both 1.5 T MRI and 16-section CT examinations. All MRI and CT images were retrospectively reviewed and evaluated in separate sessions. The fracture morphology (complete/incomplete, localization) and vertebral levels were noted at both the CT and MRI examinations. Bone marrow/peri-osseous soft-tissue oedema was also determined at MRI. Results: In total, 73 complete and 32 incomplete stress fractures were detected with CT. Sixty-seven complete, 24 incomplete fractures and eight stress reactions were detected using MRI in the same study group. Marrow oedema was also seen in eight of the complete and 20 of the incomplete fractures. The specificity, sensitivity, and accuracy of MRI in detecting fracture lines were 99.6, 86.7, and 97.2%, respectively. MRI was more accurate at the lower lumbar levels in comparison to upper lumbar levels. Conclusion: MRI has a similar diagnostic accuracy to CT in determining complete fractures with or without accompanying marrow oedema and incomplete fractures with accompanying marrow oedema, especially at the lower lumbar levels, which constitutes 94% of all fractures. At upper lumbar levels and in the incomplete fractures of the pars interarticularis with marked surrounding sclerosis, MRI has apparent limitations compared to CT imaging.

  11. Diagnostic accuracy of magnetic resonance imaging versus computed tomography in stress fractures of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Ganiyusufoglu, A.K., E-mail: kursady33@yahoo.co [Department of Radiology, Florence Nightingale Hospital, Istanbul (Turkey); Onat, L. [Department of Radiology, Florence Nightingale Hospital, Istanbul (Turkey); Karatoprak, O.; Enercan, M.; Hamzaoglu, A. [Department of Orthopedics and Traumatology, Florence Nightingale Hospital, Istanbul (Turkey)

    2010-11-15

    Aim: To compare the diagnostic accuracy of magnetic resonance imaging (MRI) with computed tomography (CT) in stress fractures of the lumbar spine. Materials and methods: Radiological and clinical data from 57 adolescents and young adults with a diagnosis of stress injury of the lumbar spine were retrospectively reviewed. All cases had undergone both 1.5 T MRI and 16-section CT examinations. All MRI and CT images were retrospectively reviewed and evaluated in separate sessions. The fracture morphology (complete/incomplete, localization) and vertebral levels were noted at both the CT and MRI examinations. Bone marrow/peri-osseous soft-tissue oedema was also determined at MRI. Results: In total, 73 complete and 32 incomplete stress fractures were detected with CT. Sixty-seven complete, 24 incomplete fractures and eight stress reactions were detected using MRI in the same study group. Marrow oedema was also seen in eight of the complete and 20 of the incomplete fractures. The specificity, sensitivity, and accuracy of MRI in detecting fracture lines were 99.6, 86.7, and 97.2%, respectively. MRI was more accurate at the lower lumbar levels in comparison to upper lumbar levels. Conclusion: MRI has a similar diagnostic accuracy to CT in determining complete fractures with or without accompanying marrow oedema and incomplete fractures with accompanying marrow oedema, especially at the lower lumbar levels, which constitutes 94% of all fractures. At upper lumbar levels and in the incomplete fractures of the pars interarticularis with marked surrounding sclerosis, MRI has apparent limitations compared to CT imaging.

  12. The evaluation of accuracy of NAA method used by P2TRR laboratory with food standard reference material analysis

    International Nuclear Information System (INIS)

    Rina M, Th.; Sri-Wardhani; Sunarko

    2003-01-01

    The NAA method is the analysis method with high precision and accuracy level. The precision and accuracy of NAA laboratory in P2TRR had been evaluated with SRM 1573a Tomato Leaf and CRM No.9 Sargasso. Samples were irradiated in RSG-GAS's rabbit system and counted with gamma spectrometry. The results obtained from this research are for the SRM 1573a sample the test could analyze 17 elements of the 40 certified elements, and for CRM No.9 sample the test could analyze 16 elements of the 30 certified elements. The result of quantitative analysis indicate the different deviation of each element between 2 -10.5 % compared to the certificate data. This deviation value <15%, this value shows that the precision and accuracy level is good enough

  13. The impact of the cycle counting in the inventory accuracy: multiple cases in industries of Paraná

    Directory of Open Access Journals (Sweden)

    Everton Drohomeretski

    2013-05-01

    Full Text Available This article aims to identify the impact of cycle counting on inventory accuracy. Multiple case studies were used as research method; these include seven case studies of companies in Paraná. A research protocol was used as the basis for collecting the data. For the data analysis, the content analysis method was used with the triangulation of collected data. For the main results, the study demonstrates the relationship between cycle counting, the level of importance attributed by the organization, the number of items and the rate of accuracy obtained. The high level of control of inventory processes, together with the use of cycle counting made it possible to eliminate the main cause of failure in inventory accuracy – errors in recording the movement of material – and with this, improve the operational efficiency of the companies.

  14. Internet search term affects the quality and accuracy of online information about developmental hip dysplasia.

    Science.gov (United States)

    Fabricant, Peter D; Dy, Christopher J; Patel, Ronak M; Blanco, John S; Doyle, Shevaun M

    2013-06-01

    The recent emphasis on shared decision-making has increased the role of the Internet as a readily accessible medical reference source for patients and families. However, the lack of professional review creates concern over the quality, accuracy, and readability of medical information available to patients on the Internet. Three Internet search engines (Google, Yahoo, and Bing) were evaluated prospectively using 3 difference search terms of varying sophistication ("congenital hip dislocation," "developmental dysplasia of the hip," and "hip dysplasia in children"). Sixty-three unique Web sites were evaluated by each of 3 surgeons (2 fellowship-trained pediatric orthopaedic attendings and 1 orthopaedic chief resident) for quality and accuracy using a set of scoring criteria based on the AAOS/POSNA patient education Web site. The readability (literacy grade level) of each Web site was assessed using the Fleisch-Kincaid score. There were significant differences noted in quality, accuracy, and readability of information depending on the search term used. The search term "developmental dysplasia of the hip" provided higher quality and accuracy compared with the search term "congenital hip dislocation." Of the 63 total Web sites, 1 (1.6%) was below the sixth grade reading level recommended by the NIH for health education materials and 8 (12.7%) Web sites were below the average American reading level (eighth grade). The quality and accuracy of information available on the Internet regarding developmental hip dysplasia significantly varied with the search term used. Patients seeking information about DDH on the Internet may not understand the materials found because nearly all of the Web sites are written at a level above that recommended for publically distributed health information. Physicians should advise their patients to search for information using the term "developmental dysplasia of the hip" or, better yet, should refer patients to Web sites that they have

  15. Speed, accuracy, and stability of laryngeal movement in singing

    Science.gov (United States)

    Titze, Ingo R.

    2004-05-01

    Motor performance is often quantified in terms of speed, strength, accuracy, and stability of a target gesture, or maintaining a given posture. In the vocal system, this involves primarily the intrinsic laryngeal muscles and the respiratory muscles. Agonist-antagonist pairs of muscles are used to position the vocal folds for phonation (vocal onset), for pitch change, and for registration (as in yodeling). Maximum speed and accuracy are discussed for vocal embellishments such as trills, trillo, scales, arpeggios, yodel, and glissando. This speed and accuracy are interpreted in terms of muscle twitch and tetanic responses obtained in vitro on animal muscles, from electromyographic recordings on humans, and from muscles not easily tested on humans. The laryngeal reflex system is also described, particularly with regard to its ability to stabilize (or destabilize) neurologic tremor originating from the central nervous system.

  16. INFLUENCE OF STRUCTURE COMPONENTS ON MACHINE TOOL ACCURACY

    Directory of Open Access Journals (Sweden)

    ConstantinSANDU

    2017-11-01

    Full Text Available For machine tools, the accuracy of the parts of the machine tool structure (after roughing should be subject to relief and natural or artificial aging. The performance of the current accuracy of machine tools as linearity or flatness was higher than 5 μm/m. Under this value there are great difficulties. The performance of the structure of the machine tools in the manufacture of structural parts of machine tools, with a flatness accuracy that the linearity of about 2 μm/m, are significant deviations form of their half-finished. This article deals with the influence of errors of form of semifinished and machined parts on them, on their shape and especially what happens to structure machine tools when the components of the structure were assembling this.

  17. Accuracy of genomic selection in European maize elite breeding populations.

    Science.gov (United States)

    Zhao, Yusheng; Gowda, Manje; Liu, Wenxin; Würschum, Tobias; Maurer, Hans P; Longin, Friedrich H; Ranc, Nicolas; Reif, Jochen C

    2012-03-01

    Genomic selection is a promising breeding strategy for rapid improvement of complex traits. The objective of our study was to investigate the prediction accuracy of genomic breeding values through cross validation. The study was based on experimental data of six segregating populations from a half-diallel mating design with 788 testcross progenies from an elite maize breeding program. The plants were intensively phenotyped in multi-location field trials and fingerprinted with 960 SNP markers. We used random regression best linear unbiased prediction in combination with fivefold cross validation. The prediction accuracy across populations was higher for grain moisture (0.90) than for grain yield (0.58). The accuracy of genomic selection realized for grain yield corresponds to the precision of phenotyping at unreplicated field trials in 3-4 locations. As for maize up to three generations are feasible per year, selection gain per unit time is high and, consequently, genomic selection holds great promise for maize breeding programs.

  18. Accuracy Improvement of Neutron Nuclear Data on Minor Actinides

    Science.gov (United States)

    Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki; Katabuchi, Tatsuya; Sano, Tadafumi; Takahashi, Yoshiyuki; Takamiya, Koichi; Pyeon, Cheol Ho; Fukutani, Satoshi; Fujii, Toshiyuki; Hori, Jun-ichi; Yagi, Takahiro; Yashima, Hiroshi

    2015-05-01

    Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program" in Japan at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background and research plan of the AIMAC project are presented.

  19. Analysis on Dynamic Transmission Accuracy for RV Reducer

    Directory of Open Access Journals (Sweden)

    Zhang Fengshou

    2017-01-01

    Full Text Available By taking rotate vector (RV reducer as the research object, the factors affecting the transmission accuracy are studied, including the machining errors of the main parts, assembly errors, clearance, micro-displacement, gear mesh stiffness and damping, bearing stiffness. Based on Newton second law, the transmission error mathematical model of RV reducer is set up. Then, the RV reducer transmission error curve is achieved by solving the mathematical model using the Runge-Kutta methods under the combined action of various error factors. Through the analysis of RV reducer transmission test, it can be found that there are similar variation trend and frequency components compared the theoretical research and experimental result. The presented method is useful to the research on dynamic transmission accuracy of RV reducer, and also applies to research the transmission accuracy of other cycloid drive systems.

  20. Process planning and accuracy distribution of marine power plant modularization

    Directory of Open Access Journals (Sweden)

    ZHANG Jinguo

    2018-02-01

    Full Text Available [Objectives] Modular shipbuilding can shorten the cycle of design and construction, lower production costs and improve the quality of products, but higher shipbuilding capabilities are required, especially for the installation of power plants. Because of such characteristics of modular shipbuilding as the high precision of docking links, long size equipment installation chain and quantitative docking interfaces, docking installation is very difficult due to high docking deviation and low accuracy of docking installation, leading to the abnormal vibration of equipment. In order to solve this problem, [Methods] on the basis of domestic shipbuilding capability, numerical calculation methods are used to analyze the accuracy distribution of modular installation. [Results] The results show that the accuracy distribution of different docking links is reasonable and feasible, and the setting of adjusting allowance matches the requirements of shipbuilding. [Conclusions] This method provides a reference for the modular construction of marine power plants.

  1. MUSCLE: multiple sequence alignment with high accuracy and high throughput.

    Science.gov (United States)

    Edgar, Robert C

    2004-01-01

    We describe MUSCLE, a new computer program for creating multiple alignments of protein sequences. Elements of the algorithm include fast distance estimation using kmer counting, progressive alignment using a new profile function we call the log-expectation score, and refinement using tree-dependent restricted partitioning. The speed and accuracy of MUSCLE are compared with T-Coffee, MAFFT and CLUSTALW on four test sets of reference alignments: BAliBASE, SABmark, SMART and a new benchmark, PREFAB. MUSCLE achieves the highest, or joint highest, rank in accuracy on each of these sets. Without refinement, MUSCLE achieves average accuracy statistically indistinguishable from T-Coffee and MAFFT, and is the fastest of the tested methods for large numbers of sequences, aligning 5000 sequences of average length 350 in 7 min on a current desktop computer. The MUSCLE program, source code and PREFAB test data are freely available at http://www.drive5. com/muscle.

  2. Geometric accuracy of wax bade models manufactured in silicon moulds

    Directory of Open Access Journals (Sweden)

    G. Budzik

    2010-01-01

    Full Text Available The article presents the test results of the geometric accuracy of wax blade models manufactured in silicon moulds in the Rapid Tooling process, with the application of the Vacuum Casting technology. In batch production casting waxes are designed for the manufacture of models and components of model sets through injection into a metal die. The objective of the tests was to determine the possibility of using traditional wax for the production of casting models in the rapid prototyping process. Blade models made of five types of casting wax were measured. The definition of the geometric accuracy of wax blade models makes it possible to introduce individual modifications aimed at improving their shape in order to increase the dimensional accuracy of blade models manufactured in the rapid prototyping process.

  3. Accuracy of the photogrametric measuring system for large size elements

    Directory of Open Access Journals (Sweden)

    M. Grzelka

    2011-04-01

    Full Text Available The aim of this paper is to present methods of estimating and guidelines for verifying the accuracy of optical photogrammetric measuringsystems, using for measurement of large size elements. Measuring systems applied to measure workpieces of a large size which oftenreach more than 10000mm require use of appropriate standards. Those standards provided by the manufacturer of photogrammetricsystems are certified and are inspected annually. To make sure that these systems work properly there was developed a special standardVDI / VDE 2634, "Optical 3D measuring systems. Imaging systems with point - by - point probing. " According to recommendationsdescribed in this standard research on accuracy of photogrametric measuring system was conducted using K class gauge blocks dedicatedto calibrate and test accuracy of classic CMMs. The paper presents results of research of estimation the actual error of indication for sizemeasurement MPEE for photogrammetric coordinate measuring system TRITOP.

  4. Accuracy Constraint Determination in Fixed-Point System Design

    Directory of Open Access Journals (Sweden)

    Serizel R

    2008-01-01

    Full Text Available Most of digital signal processing applications are specified and designed with floatingpoint arithmetic but are finally implemented using fixed-point architectures. Thus, the design flow requires a floating-point to fixed-point conversion stage which optimizes the implementation cost under execution time and accuracy constraints. This accuracy constraint is linked to the application performances and the determination of this constraint is one of the key issues of the conversion process. In this paper, a method is proposed to determine the accuracy constraint from the application performance. The fixed-point system is modeled with an infinite precision version of the system and a single noise source located at the system output. Then, an iterative approach for optimizing the fixed-point specification under the application performance constraint is defined and detailed. Finally the efficiency of our approach is demonstrated by experiments on an MP3 encoder.

  5. Phenomenological reports diagnose accuracy of eyewitness identification decisions.

    Science.gov (United States)

    Palmer, Matthew A; Brewer, Neil; McKinnon, Anna C; Weber, Nathan

    2010-02-01

    This study investigated whether measuring the phenomenology of eyewitness identification decisions aids evaluation of their accuracy. Witnesses (N=502) viewed a simulated crime and attempted to identify two targets from lineups. A divided attention manipulation during encoding reduced the rate of remember (R) correct identifications, but not the rates of R foil identifications or know (K) judgments in the absence of recollection (i.e., K/[1-R]). Both RK judgments and recollection ratings (a novel measure of graded recollection) distinguished correct from incorrect positive identifications. However, only recollection ratings improved accuracy evaluation after identification confidence was taken into account. These results provide evidence that RK judgments for identification decisions function in a similar way as for recognition decisions; are consistent with the notion of graded recollection; and indicate that measures of phenomenology can enhance the evaluation of identification accuracy. Copyright 2009 Elsevier B.V. All rights reserved.

  6. A study on temporal accuracy of OpenFOAM

    Directory of Open Access Journals (Sweden)

    Sang Bong Lee

    2017-07-01

    Full Text Available Crank–Nicolson scheme in native OpenFOAM source libraries was not able to provide 2nd order temporal accuracy of velocity and pressure since the volume flux of convective nonlinear terms was 1st accurate in time. In the present study the simplest way of getting the volume flux with 2nd order accuracy was proposed by using old fluxes. A possible numerical instability originated from an explicit estimation of volume fluxes could be handled by introducing a weighting factor which was determined by observing the ratio of the finally corrected volume flux to the intermediate volume flux at the previous step. The new calculation of volume fluxes was able to provide temporally accurate velocity and pressure with 2nd order. The improvement of temporal accuracy was validated by performing numerical simulations of 2D Taylor–Green vortex of which an exact solution was known and 2D vortex shedding from a circular cylinder.

  7. Hardware accuracy counters for application precision and quality feedback

    Science.gov (United States)

    de Paula Rosa Piga, Leonardo; Majumdar, Abhinandan; Paul, Indrani; Huang, Wei; Arora, Manish; Greathouse, Joseph L.

    2018-06-05

    Methods, devices, and systems for capturing an accuracy of an instruction executing on a processor. An instruction may be executed on the processor, and the accuracy of the instruction may be captured using a hardware counter circuit. The accuracy of the instruction may be captured by analyzing bits of at least one value of the instruction to determine a minimum or maximum precision datatype for representing the field, and determining whether to adjust a value of the hardware counter circuit accordingly. The representation may be output to a debugger or logfile for use by a developer, or may be output to a runtime or virtual machine to automatically adjust instruction precision or gating of portions of the processor datapath.

  8. Estimate of cryoscopic calculations accuracy from fusibility diagrams

    International Nuclear Information System (INIS)

    Viting, L.M.; Gorbovskaya, G.P.

    1975-01-01

    The melting points of some lead and zinc salts, that can be used as solvents for ferrites in systems: PbMoO 4 -MgFe 2 O 4 , Zn 2 V 2 O 7 -NiFe 2 O 4 , Pb 3 (VO 4 ) 2 -MgFe 2 O 4 , have been calculated in accordance with the hypotetical mechanism of the solvent dissociation. The accuracy of cryoscopic calculations based on melting point curves is evaluated. Cryoscopic calculations permit to determin the solvent activity with the accuracy of +-0.3% and the heat of its fusion, with the accuracy of +-3%. The comparison of the calculated and experimental values of the entropy of melting, as well as calculated and experimental values of the cryoscopic constant elucidates the mechanism of dissociation of both the dissolved compound and the solvent

  9. Analysis on detection accuracy of binocular photoelectric instrument optical axis parallelism digital calibration instrument

    Science.gov (United States)

    Ying, Jia-ju; Yin, Jian-ling; Wu, Dong-sheng; Liu, Jie; Chen, Yu-dan

    2017-11-01

    Low-light level night vision device and thermal infrared imaging binocular photoelectric instrument are used widely. The maladjustment of binocular instrument ocular axises parallelism will cause the observer the symptom such as dizziness, nausea, when use for a long time. Binocular photoelectric equipment digital calibration instrument is developed for detecting ocular axises parallelism. And the quantitative value of optical axis deviation can be quantitatively measured. As a testing instrument, the precision must be much higher than the standard of test instrument. Analyzes the factors that influence the accuracy of detection. Factors exist in each testing process link which affect the precision of the detecting instrument. They can be divided into two categories, one category is factors which directly affect the position of reticle image, the other category is factors which affect the calculation the center of reticle image. And the Synthesize error is calculated out. And further distribute the errors reasonably to ensure the accuracy of calibration instruments.

  10. Accuracy of the Bethe approximation for hyperparameter estimation in probabilistic image processing

    International Nuclear Information System (INIS)

    Tanaka, Kazuyuki; Shouno, Hayaru; Okada, Masato; Titterington, D M

    2004-01-01

    We investigate the accuracy of statistical-mechanical approximations for the estimation of hyperparameters from observable data in probabilistic image processing, which is based on Bayesian statistics and maximum likelihood estimation. Hyperparameters in statistical science correspond to interactions or external fields in the statistical-mechanics context. In this paper, hyperparameters in the probabilistic model are determined so as to maximize a marginal likelihood. A practical algorithm is described for grey-level image restoration based on a Gaussian graphical model and the Bethe approximation. The algorithm corresponds to loopy belief propagation in artificial intelligence. We examine the accuracy of hyperparameter estimation when we use the Bethe approximation. It is well known that a practical algorithm for probabilistic image processing can be prescribed analytically when a Gaussian graphical model is adopted as a prior probabilistic model in Bayes' formula. We are therefore able to compare, in a numerical study, results obtained through mean-field-type approximations with those based on exact calculation

  11. The accuracy of webcams in 2D motion analysis: sources of error and their control

    International Nuclear Information System (INIS)

    Page, A; Candelas, P; Belmar, F; Moreno, R

    2008-01-01

    In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost

  12. The accuracy of webcams in 2D motion analysis: sources of error and their control

    Energy Technology Data Exchange (ETDEWEB)

    Page, A; Candelas, P; Belmar, F [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Valencia (Spain); Moreno, R [Instituto de Biomecanica de Valencia, Valencia (Spain)], E-mail: alvaro.page@ibv.upv.es

    2008-07-15

    In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost.

  13. Test accuracy of metabolic indicators in predicting decreased fertility in dairy cows

    DEFF Research Database (Denmark)

    Lomander, H; Gustafsson, H; Svensson, C

    2012-01-01

    Negative energy balance is a known risk factor for decreased fertility in dairy cows. This study evaluated the accuracy of plasma concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and insulin-like growth factor 1 (IGF-1)—factors related to negative energy balance...... was low when metabolic indicators measured as single values in early lactation were used to predict fertility in dairy cows, but accuracy was influenced by cow-level factors such as parity. The prevalence of the target condition (in this case, decreased fertility) also influences test usefulness......—in predicting decreased fertility. One plasma sample per cow was collected from 480 cows in 12 herds during the period from d 4 to 21 in milk and analyzed for NEFA, BHBA, and IGF-1. For each cow, data on breed, parity, calving date, gynecological examinations, and insemination dates were obtained. Milk samples...

  14. High-Accuracy Spherical Near-Field Measurements for Satellite Antenna Testing

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2017-01-01

    The spherical near-field antenna measurement technique is unique in combining several distinct advantages and it generally constitutes the most accurate technique for experimental characterization of radiation from antennas. From the outset in 1970, spherical near-field antenna measurements have...... matured into a well-established technique that is widely used for testing antennas for many wireless applications. In particular, for high-accuracy applications, such as remote sensing satellite missions in ESA's Earth Observation Programme with uncertainty requirements at the level of 0.05dB - 0.10d......B, the spherical near-field antenna measurement technique is generally superior. This paper addresses the means to achieving high measurement accuracy; these include the measurement technique per se, its implementation in terms of proper measurement procedures, the use of uncertainty estimates, as well as facility...

  15. One process is not enough! A speed-accuracy tradeoff study of recognition memory.

    Science.gov (United States)

    Boldini, Angela; Russo, Riccardo; Avons, S E

    2004-04-01

    Speed-accuracy tradeoff (SAT) methods have been used to contrast single- and dual-process accounts of recognition memory. In these procedures, subjects are presented with individual test items and are required to make recognition decisions under various time constraints. In this experiment, we presented word lists under incidental learning conditions, varying the modality of presentation and level of processing. At test, we manipulated the interval between each visually presented test item and a response signal, thus controlling the amount of time available to retrieve target information. Study-test modality match had a beneficial effect on recognition accuracy at short response-signal delays (deep than from shallow processing at study only at relatively long response-signal delays (> or =300 msec). The results are congruent with views suggesting that both fast familiarity and slower recollection processes contribute to recognition memory.

  16. EFFECT OF DIGITAL FRINGE PROJECTION PARAMETERS ON 3D RECONSTRUCTION ACCURACY

    Directory of Open Access Journals (Sweden)

    A. Babaei

    2013-09-01

    This paper aims to evaluate different parameters which affect the accuracy of the final results. For this purpose, some test were designed and implemented. These tests assess the number of phase shifts, spatial frequency of the fringe pattern, light condition, noise level of images, and the color and material of target objects on the quality of resulted phase map. The evaluation results demonstrate that digital fringe projection method is capable of obtaining depth map of complicated object with high accuracy. The contrast test results showed that this method is able to work under different ambient light condition; although at places with high light condition will not work properly. The results of implementation on different objects with various materials, color and shapes demonstrate the high capability of this method of 3D reconstruction.

  17. Accuracy of prognosis estimates by four palliative care teams: a prospective cohort study

    Directory of Open Access Journals (Sweden)

    Costantini Massimo

    2002-03-01

    Full Text Available Abstract Background Prognosis estimates are used to access services, but are often inaccurate. This study aimed to determine the accuracy of giving a prognosis range. Methods and measurements A prospective cohort study in four multi-professional palliative care teams in England collected data on 275 consecutive cancer referrals who died. Prognosis estimates (minimum – maximum at referral, patient characteristics, were recorded by staff, and later compared with actual survival. Results Minimum survival estimates ranged Conclusions Offering a prognosis range has higher levels of accuracy (about double than traditional estimates, but is still very often inaccurate, except very close to death. Where possible clinicians should discuss scenarios with patients, rather than giving a prognosis range.

  18. Dependence of Dynamic Modeling Accuracy on Sensor Measurements, Mass Properties, and Aircraft Geometry

    Science.gov (United States)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations

  19. Accuracy required and achievable in radiotherapy dosimetry: have modern technology and techniques changed our views?

    Science.gov (United States)

    Thwaites, David

    2013-06-01

    In this review of the accuracy required and achievable in radiotherapy dosimetry, older approaches and evidence-based estimates for 3DCRT have been reprised, summarising and drawing together the author's earlier evaluations where still relevant. Available evidence for IMRT uncertainties has been reviewed, selecting information from tolerances, QA, verification measurements, in vivo dosimetry and dose delivery audits, to consider whether achievable uncertainties increase or decrease for current advanced treatments and practice. Overall there is some evidence that they tend to increase, but that similar levels should be achievable. Thus it is concluded that those earlier estimates of achievable dosimetric accuracy are still applicable, despite the changes and advances in technology and techniques. The one exception is where there is significant lung involvement, where it is likely that uncertainties have now improved due to widespread use of more accurate heterogeneity models. Geometric uncertainties have improved with the wide availability of IGRT.

  20. Accuracy of young male drivers’ self-assessments of driving skill

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    2017-01-01

    Accurate self-assessment of skill is important because it creates an appropriate level of confidence and hence behaviour. Inaccurate self-assessment of driving ability has been linked to reckless driving and accidents. Inaccurate self-assessment of driving skills may be a contributing factor...... to the over-representation of young male drivers in accident statistics. Most previous research on self-assessment of driving skills did not compare self-reported skills to objectively measured driving skills, so the aims of this study were: (1) to test the accuracy of young male drivers’ self......-assessments of specific driving skills by comparing them with performance in a driving simulator; (2) to test whether self-assessment accuracy varied with driving skill, driving experience and sensation-seeking propensity. We found that young male drivers’ self-assessments were inconsistent with their driving performance...

  1. Contributions of speed and accuracy to translational selection in bacteria.

    Directory of Open Access Journals (Sweden)

    Wenqi Ran

    Full Text Available Among bacteria, we have previously shown that species that are capable of rapid growth have stronger selection on codon usage than slow growing species, and possess higher numbers of rRNA and tRNA genes. This suggests that fast-growers are adapted for fast protein synthesis. There is also considerable evidence that codon usage is influenced by accuracy of translation, and some authors have argued that accuracy is more important than speed. Here we compare the strength of the two effects by studying the codon usages in high and low expression genes and on conserved and variable sites within high expression genes. We introduce a simple statistical method that can be used to assess the significance and the strength of the two types of bias in the same sets of sequences. We compare our statistical measure of codon bias to the common used codon adaptation index, and show that the new measure is preferable for three reasons for the purposes of this analysis. Across a large sample of bacterial genomes, both effects from speed and accuracy are clearly visible, although the speed effect appears to be much stronger than the accuracy effect and is found to be significant in a larger proportion of genomes. It is also difficult to explain the correlation of codon bias in the high expression genes with growth rates and numbers of copies of tRNA and rRNA genes on the basis of selection for accuracy. Hence we conclude that selection for translational speed is a dominant effect in driving codon usage bias in fast-growing bacteria, with selection for accuracy playing a small supplementary role.

  2. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    International Nuclear Information System (INIS)

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-01-01

    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

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

    Science.gov (United States)

    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.

  4. Diagnostic accuracy of sonography for pleural effusion: systematic review

    Directory of Open Access Journals (Sweden)

    Alexandre Grimberg

    Full Text Available CONTEXT AND OBJECTIVE: The initial method for evaluating the presence of pleural effusion was chest radiography. Isolated studies have shown that sonography has greater accuracy than radiography for this diagnosis; however, no systematic reviews on this matter are available in the literature. Thus, the aim of this study was to evaluate the accuracy of sonography in detecting pleural effusion, by means of a systematic review of the literature. DESIGN AND SETTING: This was a systematic review with meta-analysis on accuracy studies. This study was conducted in the Department of Diagnostic Imaging and in the Brazilian Cochrane Center, Discipline of Emergency Medicine and Evidence-Based Medicine, Department of Medicine, Universidade Federal de São Paulo (Unifesp, São Paulo, Brazil. METHOD: The following databases were searched: Cochrane Library, Medline, Web of Science, Embase and Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs. The references of relevant studies were also screened for additional citations of interest. Studies in which the accuracy of sonography for detecting pleural effusion was tested, with an acceptable reference standard (computed tomography or thoracic drainage, were included. RESULTS: Four studies were included. All of them showed that sonography had high sensitivity, specificity and accuracy for detecting pleural effusions. The mean sensitivity was 93% (95% confidence interval, CI: 89% to 96%, and specificity was 96% (95% CI: 95% to 98%. CONCLUSIONS: In different populations and clinical settings, sonography showed consistently high sensitivity, specificity and accuracy for detecting fluid in the pleural space.

  5. Emotional state and its impact on voice authentication accuracy

    Science.gov (United States)

    Voznak, Miroslav; Partila, Pavol; Penhaker, Marek; Peterek, Tomas; Tomala, Karel; Rezac, Filip; Safarik, Jakub

    2013-05-01

    The paper deals with the increasing accuracy of voice authentication methods. The developed algorithm first extracts segmental parameters, such as Zero Crossing Rate, the Fundamental Frequency and Mel-frequency cepstral coefficients from voice. Based on these parameters, the neural network classifier detects the speaker's emotional state. These parameters shape the distribution of neurons in Kohonen maps, forming clusters of neurons on the map characterizing a particular emotional state. Using regression analysis, we can calculate the function of the parameters of individual emotional states. This relationship increases voice authentication accuracy and prevents unjust rejection.

  6. Study on Accuracy of Judgments by Chinese Fingerprint Examiners

    Directory of Open Access Journals (Sweden)

    Shiquan Liu

    2015-01-01

    Full Text Available The interpretation of fingerprint evidence depends on the judgments of fingerprint examiners. This study assessed the accuracy of different judgments made by fingerprint examiners following the Analysis, Comparison, and Evaluation (ACE process. Each examiner was given five marks for analysis, comparison, and evaluation. We compared the experts′ judgments against the ground truth and used an annotation platform to evaluate how Chinese fingerprint examiners document their comparisons during the identification process. The results showed that different examiners demonstrated different accuracy of judgments and different mechanisms to reach them.

  7. Accuracy of single photoelectron time spread measurement of fast photomultipliers

    International Nuclear Information System (INIS)

    Leskovar, B.

    1975-01-01

    The accuracy of time spread measurements of fast photomultipliers was investigated, using single photoelectrons. The effect of the finite light pulse width on the measurement accuracy was determined and discussed. Experimental data were obtained on a special measuring system for light pulse widths ranging from 200 psec to 10 nsec, using fast photomultipliers 8850 and C31024 with optimized operating conditions for minimum transit time spread. A modified exponential function expression and curve-fitting parameters are given, which fit closely the experimentally obtained data over a wide dynamic range of light pulse widths. (U.S.)

  8. Accuracy of helium accumulation fluence monitor for fast reactor dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Chikara; Aoyama, Takafumi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1998-03-01

    A helium (He) accumulation fluence monitor (HAFM) has been developed for fast reactor dosimetry. In order to evaluate the measurement accuracy of neutron fluence by the HAFM method, the HAFMs of enriched boron (B) and beryllium (Be) were irradiated in the Fast Neutron Source Reactor `YAYOI`. The number of He atoms produced in the HAFMs were measured and compared with the calculated values. As a result of this study, it was confirmed that the neutron fluence could be measured within 5 % by the HAFM method, and that met the required accuracy for fast reactor dosimetry. (author)

  9. Optimization of drift gases for accuracy in pressurized drift tubes

    CERN Document Server

    Kirchner, J J; Dinner, A R; Fidkowski, K J; Wyatt, J H

    2001-01-01

    Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space-time relationships are best for reconstruction, but difficult to achieve in the $E \\propto \\frac{1}{r}$ field. Previous mixtures, which contained methane or other organic quenchers, are disfavored because of ageing problems. From our studies of nitrogen and carbon dioxide, two mixtures with only small deviations from linearity were determined and measured. Scaling laws for different pressures and magnetic fields are also given.

  10. Optimization of drift gases for accuracy in pressurized drift tubes

    International Nuclear Information System (INIS)

    Kirchner, J.J.; Becker, U.J.; Dinner, R.B.; Fidkowski, K.J.; Wyatt, J.H.

    2001-01-01

    Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space-time relationships are best for reconstruction, but difficult to achieve in the E∝1/r field. Previous mixtures, which contained methane or other organic quenchers, are disfavored because of ageing problems. From our studies of nitrogen and carbon dioxide, two mixtures with only small deviations from linearity were determined and measured. Scaling laws for different pressures and magnetic fields are also given

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

    Science.gov (United States)

    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%.

  12. Millisecond accuracy video display using OpenGL under Linux.

    Science.gov (United States)

    Stewart, Neil

    2006-02-01

    To measure people's reaction times to the nearest millisecond, it is necessary to know exactly when a stimulus is displayed. This article describes how to display stimuli with millisecond accuracy on a normal CRT monitor, using a PC running Linux. A simple C program is presented to illustrate how this may be done within X Windows using the OpenGL rendering system. A test of this system is reported that demonstrates that stimuli may be consistently displayed with millisecond accuracy. An algorithm is presented that allows the exact time of stimulus presentation to be deduced, even if there are relatively large errors in measuring the display time.

  13. Sensitivity, uncertainty assessment, and target accuracies related to radiotoxicity evaluation

    International Nuclear Information System (INIS)

    Palmiotti, G.; Salvatores, M.; Hill, R.N.

    1994-01-01

    Time-dependent sensitivity techniques, which have been used in the past for standard reactor applications, are adapted to calculate the impact of data uncertainties and to estimate target data accuracies in radiotoxicity evaluations. The methodology is applied to different strategies of radioactive waste management connected with the European Fast Reactor and the Integral Fast Reactor fuel cycles. Results are provided in terms of sensitivity coefficients of basic data (cross sections and decay constants), uncertainties of global radiotoxicity at different times of storing after discharge, and target data accuracies needed to satisfy maximum uncertainty limits

  14. Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors

    Directory of Open Access Journals (Sweden)

    David K. Chang

    2017-10-01

    Full Text Available Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper.

  15. Three-dimensional accuracy of plastic transfer impression copings for three implant systems.

    Science.gov (United States)

    Teo, Juin Wei; Tan, Keson B; Nicholls, Jack I; Wong, Keng Mun; Uy, Joanne

    2014-01-01

    The purpose of this study was to compare the three-dimensional accuracy of indirect plastic impression copings and direct implant-level impression copings from three implant systems (Nobel Biocare [NB], Biomet 3i [3i], and Straumann [STR]) at three interimplant buccolingual angulations (0, 8, and 15 degrees). Two-implant master models were used to simulate a three-unit implant fixed partial denture. Test models were made from Impregum impressions using direct implant-level impression copings (DR). Abutments were then connected to the master models for impressions using the plastic impression copings (INDR) at three different angulations for a total of 18 test groups (n = 5 in each group). A coordinate measuring machine was used to measure linear distortions, three-dimensional (3D) distortions, angular distortions, and absolute angular distortions between the master and test models. Three-way analysis of variance showed that the implant system had a significant effect on 3D distortions and absolute angular distortions in the x- and y-axes. Interimplant angulation had a significant effect on 3D distortions and absolute angular distortions in the y-axis. Impression technique had a significant effect on absolute angular distortions in the y-axis. With DR, the NB and 3i systems were not significantly different. With INDR, 3i appeared to have less distortion than the other systems. Interimplant angulations did not significantly affect the accuracy of NBDR, 3iINDR, and STRINDR. The accuracy of INDR and DR was comparable at all interimplant angulations for 3i and STR. For NB, INDR was comparable to DR at 0 and 8 degrees but was less accurate at 15 degrees. Three-dimensional accuracy of implant impressions varied with implant system, interimplant angulation, and impression technique.

  16. Evaluation of accuracy in implant site preparation performed in single- or multi-step drilling procedures.

    Science.gov (United States)

    Marheineke, Nadine; Scherer, Uta; Rücker, Martin; von See, Constantin; Rahlf, Björn; Gellrich, Nils-Claudius; Stoetzer, Marcus

    2018-06-01

    Dental implant failure and insufficient osseointegration are proven results of mechanical and thermal damage during the surgery process. We herein performed a comparative study of a less invasive single-step drilling preparation protocol and a conventional multiple drilling sequence. Accuracy of drilling holes was precisely analyzed and the influence of different levels of expertise of the handlers and additional use of drill template guidance was evaluated. Six experimental groups, deployed in an osseous study model, were representing template-guided and freehanded drilling actions in a stepwise drilling procedure in comparison to a single-drill protocol. Each experimental condition was studied by the drilling actions of respectively three persons without surgical knowledge as well as three highly experienced oral surgeons. Drilling actions were performed and diameters were recorded with a precision measuring instrument. Less experienced operators were able to significantly increase the drilling accuracy using a guiding template, especially when multi-step preparations are performed. Improved accuracy without template guidance was observed when experienced operators were executing single-step versus multi-step technique. Single-step drilling protocols have shown to produce more accurate results than multi-step procedures. The outcome of any protocol can be further improved by use of guiding templates. Operator experience can be a contributing factor. Single-step preparations are less invasive and are promoting osseointegration. Even highly experienced surgeons are achieving higher levels of accuracy by combining this technique with template guidance. Hereby template guidance enables a reduction of hands-on time and side effects during surgery and lead to a more predictable clinical diameter.

  17. Improving Accuracy of Processing by Adaptive Control Techniques

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available When machining the work-pieces a range of scatter of the work-piece dimensions to the tolerance limit is displaced in response to the errors. To improve an accuracy of machining and prevent products from defects it is necessary to diminish the machining error components, i.e. to improve the accuracy of machine tool, tool life, rigidity of the system, accuracy of adjustment. It is also necessary to provide on-machine adjustment after a certain time. However, increasing number of readjustments reduces the performance and high machine and tool requirements lead to a significant increase in the machining cost.To improve the accuracy and machining rate, various devices of active control (in-process gaging devices, as well as controlled machining through adaptive systems for a technological process control now become widely used. Thus, the accuracy improvement in this case is reached by compensation of a majority of technological errors. The sensors of active control can provide improving the accuracy of processing by one or two quality classes, and simultaneous operation of several machines.For efficient use of sensors of active control it is necessary to develop the accuracy control methods by means of introducing the appropriate adjustments to solve this problem. Methods based on the moving average, appear to be the most promising for accuracy control, since they contain information on the change in the last several measured values of the parameter under control.When using the proposed method in calculation, the first three members of the sequence of deviations remain unchanged, therefore 1 1 x  x , 2 2 x  x , 3 3 x  x Then, for each i-th member of the sequence we calculate that way: , ' i i i x  x  k x , where instead of the i x values will be populated with the corresponding values ' i x calculated as an average of three previous members:3 ' 1  2  3  i i i i x x x x .As a criterion for the estimate of the control

  18. The Episodic Engram Transformed: Time Reduces Retrieval-Related Brain Activity but Correlates It with Memory Accuracy

    Science.gov (United States)

    Furman, Orit; Mendelsohn, Avi; Dudai, Yadin

    2012-01-01

    We took snapshots of human brain activity with fMRI during retrieval of realistic episodic memory over several months. Three groups of participants were scanned during a memory test either hours, weeks, or months after viewing a documentary movie. High recognition accuracy after hours decreased after weeks and remained at similar levels after…

  19. Does methodology matter in eyewitness identification research? The effect of live versus video exposure on eyewitness identification accuracy.

    Science.gov (United States)

    Pozzulo, Joanna D; Crescini, Charmagne; Panton, Tasha

    2008-01-01

    The present study examined the effect of mode of target exposure (live versus video) on eyewitness identification accuracy. Adult participants (N=104) were exposed to a staged crime that they witnessed either live or on videotape. Participants were then asked to rate their stress and arousal levels prior to being presented with either a target-present or -absent simultaneous lineup. Across target-present and -absent lineups, mode of target exposure did not have a significant effect on identification accuracy. However, mode of target exposure was found to have a significant effect on stress and arousal levels. Participants who witnessed the crime live had higher levels of stress and arousal than those who were exposed to the videotaped crime. A higher level of arousal was significantly related to poorer identification accuracy for those in the video condition. For participants in the live condition however, stress and arousal had no effect on eyewitness identification accuracy. Implications of these findings in regards to the generalizability of laboratory-based research on eyewitness testimony to real-life crime are discussed.

  20. Anticipating a Post-Task Activity: The Effects on Accuracy, Complexity, and Fluency of Second Language Performance

    Science.gov (United States)

    Foster, Pauline; Skehan, Peter

    2013-01-01

    The concept of focus on form has been influential in second language (L2) acquisition and pedagogy. One example of the implementation of focus on form is a post-task activity (e.g., anticipation of a public performance) that can selectively orient learners toward increased levels of accuracy. The present research proposes a new operationalization…