WorldWideScience

Sample records for accuracy

  1. 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.

  2. Rethinking Empathic Accuracy

    OpenAIRE

    Meadors, Joshua

    2014-01-01

    The present study is a methodological examination of the implicit empathic accuracy measure introduced by Zaki, Ochsner, and Bolger (2008). Empathic accuracy (EA) is defined as the ability to understand another person's thoughts and feelings (Ickes, 1993). Because this definition is similar to definitions of cognitive empathy (e.g., Shamay-Tsoory, 2011) and because affective empathy does not appear to be related to empathic accuracy (Zaki et al., 2008), the Basic Empathy Scale--which measures...

  3. Accuracy of Sphygmomanometers

    OpenAIRE

    Basak, Okay

    2014-01-01

    One of the factors affecting the accuracy of readings of blood pressure is the equipment used. Defects or inaccuracy of aneroid sphygmomanometers may be source of error in blood pressure measurement. We inspected 100 sphygmomanometers for physical defects and assessed their accuracy against a standard mercury manometer at four different pressure points. 46 of the 100 sphygmomanometers were determined to be intolerant (deviation from the mercury manometer by greater than±3 mm Hg at two or more...

  4. Evaluating Measurement Accuracy

    CERN Document Server

    Rabinovich, Semyon G

    2010-01-01

    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. Although multiple measurements are the focus of current theory, single measurements are the ones most commonly used. This book answers fundamental questions not addressed by present theory, such as how to discover the complete uncertainty of a measurement result. In developing a general theory of processing experimental data, this book, for the first time, presents the postulates of the theory of measurements. It introduces several new terms and definitions about the relationship between the accuracy of measuring instruments and measurements utilizing these instruments. It also offers well-grounded and practical methods for combining the components of measurement inaccuracy. From developing the theory of indirect measurements to proposing new methods of reduction in place of the traditional ones, this work encompasses the ful...

  5. The Truth about Accuracy

    NARCIS (Netherlands)

    Buekens, F.A.I.; Truyen, Frederick; Martini, Carlo; Boumans, Marcel

    2014-01-01

    When we evaluate the outcomes of investigative actions as justified or unjustified, good or bad, rational or irrational, we make, in a broad sense of the term, evaluative judgements about them. We look at operational accuracy as a desirable and evaluable quality of the outcomes and explore how the c

  6. Reconceptualizing metacomprehension calibration accuracy

    OpenAIRE

    Egan, Rylan Graham

    2012-01-01

    Accurate judgment of text comprehension is compulsory for learners to effectively self-regulate learning from text. Unfortunately, until relatively recently the literature on text comprehension judgment, termed metacomprehension, has shown learners to be inaccurate in their judgments. Over the last decade researchers have discovered that when learners use delayed summaries of text to make judgments metacomprehension accuracy increases. In contrast, when learners use individual differences (e....

  7. Accuracy of tablet splitting.

    Science.gov (United States)

    McDevitt, J T; Gurst, A H; Chen, Y

    1998-01-01

    We attempted to determine the accuracy of manually splitting hydrochlorothiazide tablets. Ninety-four healthy volunteers each split ten 25-mg hydrochlorothiazide tablets, which were then weighed using an analytical balance. Demographics, grip and pinch strength, digit circumference, and tablet-splitting experience were documented. Subjects were also surveyed regarding their willingness to pay a premium for commercially available, lower-dose tablets. Of 1752 manually split tablet portions, 41.3% deviated from ideal weight by more than 10% and 12.4% deviated by more than 20%. Gender, age, education, and tablet-splitting experience were not predictive of variability. Most subjects (96.8%) stated a preference for commercially produced, lower-dose tablets, and 77.2% were willing to pay more for them. For drugs with steep dose-response curves or narrow therapeutic windows, the differences we recorded could be clinically relevant.

  8. Reticence, Accuracy and Efficacy

    Science.gov (United States)

    Oreskes, N.; Lewandowsky, S.

    2015-12-01

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

  9. Determining Geometric Accuracy in Turning

    Institute of Scientific and Technical Information of China (English)

    Kwong; Chi; Kit; A; Geddam

    2002-01-01

    Mechanical components machined to high levels of ac cu racy are vital to achieve various functional requirements in engineering product s. In particular, the geometric accuracy of turned components play an important role in determining the form, fit and function of mechanical assembly requiremen ts. The geometric accuracy requirements of turned components are usually specifi ed in terms of roundness, straightness, cylindricity and concentricity. In pract ice, the accuracy specifications achievable are infl...

  10. 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 diff...... classification accuracy obscures the aim of MGR: to select labels indistinguishable from those a person would choose....

  11. 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…

  12. Process Analysis Via Accuracy Control

    Science.gov (United States)

    1982-02-01

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

  13. 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...... 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...... represented a useful tool for learning; 90% felt that virtual dermatopathology is useful tool for teaching dermatopathology. Conclusion No significant difference was observed in diagnostic accuracy using virtual dermatopathology compared to photomicrographs. Most participants felt virtual dermatopathology...

  14. Improving Speaking Accuracy through Awareness

    Science.gov (United States)

    Dormer, Jan Edwards

    2013-01-01

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

  15. Psychology Textbooks: Examining Their Accuracy

    Science.gov (United States)

    Steuer, Faye B.; Ham, K. Whitfield, II

    2008-01-01

    Sales figures and recollections of psychologists indicate textbooks play a central role in psychology students' education, yet instructors typically must select texts under time pressure and with incomplete information. Although selection aids are available, none adequately address the accuracy of texts. We describe a technique for sampling…

  16. Astronomic Position Accuracy Capability Study.

    Science.gov (United States)

    1979-10-01

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

  17. High accuracy flexural hinge development

    Science.gov (United States)

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

    2005-07-01

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

  18. Municipal water consumption forecast accuracy

    Science.gov (United States)

    Fullerton, Thomas M.; Molina, Angel L.

    2010-06-01

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

  19. A Review of Sodar Accuracy

    DEFF Research Database (Denmark)

    Bradley, Stuart; Mikkelsen, Torben

    2012-01-01

    be large. On a uniform terrain site, differences between a SODAR and a mastmounted cup anemometer will arise due to turbulent fluctuations and wind components being measured in different spaces, as well as to variable background noise. We develop theories for turbulence-related random fluctuations due......What accuracy and reliability can today be expected from SODAR wind measurements? Is there traceable evidence for performance? Environmental factors, turbulent fluctuations and non-uniform terrain all affect the wind speed uncertainty. So site-to-site variations for SODAR-mast comparisons can...

  20. Improving accuracy of holes honing

    Directory of Open Access Journals (Sweden)

    Ivan М. Buykli

    2015-03-01

    Full Text Available Currently, in precision engineering industry tolerances for linear dimensions and tolerances on shape of surfaces of processing parts are steadily tightened These requirements are especially relevant in processing of holes. Aim of the research is to improve accuracy and to enhance the technological capabilities of holes honing process and, particularly, of blind holes honing. Based on formal logic the analysis of formation of processing errors is executed on the basis of consideration of schemes of irregularity of dimensional wear and tear along the length of the cutting elements. With this, the possibilities of compensating this irregularities and, accordingly, of control of accuracy of processing applied to the honing of both throughout and blind holes are specified. At the same time, a new method of honing is developed, it is protected by the patent of Ukraine for invention. The method can be implemented both on an existing machine tools at insignificant modernization of its system of processing cycle control and on newly designed ones.

  1. Knowledge discovery by accuracy maximization.

    Science.gov (United States)

    Cacciatore, Stefano; Luchinat, Claudio; Tenori, Leonardo

    2014-04-01

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

  2. Increasing Accuracy in Environmental Measurements

    Science.gov (United States)

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

    2016-04-01

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

  3. Diagnostic accuracy of the care dependency scale

    NARCIS (Netherlands)

    Dijkstra, Ate; Tiesinga, LJ; Plantinga, L; Dassen, TWN; Veltman, G.

    2005-01-01

    Aim. This paper reports an investigation of the diagnostic accuracy of the Care Dependency Scale (CDS). Background. Assessment tools can be described in terms of diagnostic accuracy, or the ability to correctly classify subjects into clinically relevant subgroups. Diagnostic accuracy can be determin

  4. Astrophysics with Microarcsecond Accuracy Astrometry

    Science.gov (United States)

    Unwin, Stephen C.

    2008-01-01

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

  5. 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.

  6. Optimal Calibration Accuracy for Gravitational Wave Detectors

    CERN Document Server

    Lindblom, Lee

    2009-01-01

    Calibration errors in the response function of a gravitational wave detector degrade its ability to detect and then to measure the properties of any detected signals. This paper derives the needed levels of calibration accuracy for each of these data-analysis tasks. The levels derived here are optimal in the sense that lower accuracy would result in missed detections and/or a loss of measurement precision, while higher accuracy would be made irrelevant by the intrinsic noise level of the detector. Calibration errors affect the data-analysis process in much the same way as errors in theoretical waveform templates. The optimal level of calibration accuracy is expressed therefore as a joint limit on modeling and calibration errors: increased accuracy in one reduces the accuracy requirement in the other.

  7. 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 pri

  8. 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…

  9. 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.

  10. Anatomy-aware measurement of segmentation accuracy

    Science.gov (United States)

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

    2016-03-01

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

  11. The accuracy of general practitioner workforce projections.

    NARCIS (Netherlands)

    Greuningen, M. van; Batenburg, R.S.; Velden, L.F.J. van der

    2013-01-01

    Background: Health workforce projections are important instruments to prevent imbalances in the health workforce. For both the tenability and further development of these projections, it is important to evaluate the accuracy of workforce projections. In the Netherlands, health workforce projections

  12. 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...

  13. Accuracy and Efficiency of Raytracing Photoionisation Algorithms

    CERN Document Server

    Mackey, Jonathan

    2012-01-01

    Three non-equilibrium photoionisation algorithms for hydrodynamical grid-based simulation codes are compared in terms of accuracy, timestepping criteria, and parallel scaling. Explicit methods with first order time accuracy for photon conservation must use very restrictive timestep criteria to accurately track R-type ionisation fronts. A second order accurate algorithm is described which, although it requires more work per step, allows much longer timesteps and is consequently more efficient. Implicit methods allow ionisation fronts to cross many grid cells per timestep while maintaining photon conservation accuracy. It is shown, however, that errors are much larger for multi-frequency radiation then for monochromatic radiation with the implicit algorithm used here, and large errors accrue when an ionisation front crosses many optical depths in a single step. The accuracy and convergence rates of the different algorithms are tested with a large number of timestepping criteria to identify the best criterion fo...

  14. Systematic reviews of diagnostic test accuracy.

    Science.gov (United States)

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

    2008-12-16

    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-operating characteristic or the bivariate model for the data analysis. Challenges that remain are the poor reporting of original diagnostic test accuracy studies and difficulties with the interpretation of the results of diagnostic test accuracy research.

  15. Strategies to Increase Accuracy in Text Classification

    NARCIS (Netherlands)

    Blommesteijn, D.

    2014-01-01

    Text 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 study performed

  16. Moyamoya disease: diagnostic accuracy of MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, I. [Dept. of Radiology, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan); Suzuki, [Dept. of Radiology, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan); Matsushima, Y. [Dept. of Neurosurgery, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan)

    1995-07-01

    MRI may be employed to investigate moyamoya disease, since it provides vascular information without use of contrast medium. We reported the usefulness and limitations of MR angiography (MRA) in moyamoya disease. To our knowledge, no report has appeared dealing with the diagnostic accuracy of MRI in a large number of cases of moyamoya disease, although MRI is used more commonly than MRA. We therefore undertook to evaluate the accuracy of MRI in moyamoya disease. (orig.)

  17. Why do delayed summaries improve metacomprehension accuracy?

    Science.gov (United States)

    Anderson, Mary C M; Thiede, Keith W

    2008-05-01

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

  18. Decreased interoceptive accuracy following social exclusion.

    Science.gov (United States)

    Durlik, Caroline; Tsakiris, Manos

    2015-04-01

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

  19. 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...

  20. Field Accuracy Test of Rpas Photogrammetry

    Science.gov (United States)

    Barry, P.; Coakley, R.

    2013-08-01

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

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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…

  6. ACCURACY AND FLUENCY IN COMMUNICATIVE LANGUAGE TEACHING

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Ⅰ. Introduction In English language teaching, at whatever level, teachers feel it very important to focus on accuracy and fluency in a pedagogic way. It is now widely accepted that neither of them should be focused on alone all the way through the teaching process. From our teaching experience, we can see that to some extent this is true.

  7. On the Accuracy of Galileo's Observations

    CERN Document Server

    Graney, Christopher M

    2008-01-01

    Galileo Galilei had sufficient skill as an observer and instrument builder to be able to measure the positions and apparent sizes of objects seen through his telescopes to an accuracy of 2" or better. However, Galileo had no knowledge of wave optics, so when he was measuring stellar apparent sizes he was producing very accurate measurements of diffraction artifacts and not physical bodies.

  8. 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...... in using robots for image data set generation....

  9. Observed Consultation: Confidence and Accuracy of Assessors

    Science.gov (United States)

    Tweed, Mike; Ingham, Christopher

    2010-01-01

    Judgments made by the assessors observing consultations are widely used in the assessment of medical students. The aim of this research was to study judgment accuracy and confidence and the relationship between these. Assessors watched recordings of consultations, scoring the students on: a checklist of items; attributes of consultation; a…

  10. Adult Metacomprehension: Judgment Processes and Accuracy Constraints

    Science.gov (United States)

    Zhao, Qin; Linderholm, Tracy

    2008-01-01

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

  11. 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.

  12. 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…

  13. High accuracy FIONA-AFM hybrid imaging.

    Science.gov (United States)

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

    2011-04-01

    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 ≥8nm 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 (5-10nm) information about the conformational properties of multi-protein complexes and the fluorescence can indicate spatial relationships of the proteins in the complexes.

  14. 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.

  15. Seasonal Effects on GPS PPP Accuracy

    Science.gov (United States)

    Saracoglu, Aziz; Ugur Sanli, D.

    2016-04-01

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

  16. Accuracy assessment of an industrial actuator

    DEFF Research Database (Denmark)

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

    2016-01-01

    of length measurements of grade 0 steel gauge blocks. Measurements with different values of contact force were performed to assess its influence. A statistical analysis of the experimental data was performed to support the accuracy assessment. Systematic effects were identified and corrected. An expanded...

  17. 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.; Bowman, K.; Brindley, H.; Butler, J. J.; Collins, W.; Dykema, J. A.; Doelling, D. R.; Feldman, D. R.; Fox, N.; Huang, X.; Holz, R.; Huang, Y.; Jennings, D.; Jin, Z.; Johnson, D. G.; Jucks, K.; Kato, S.; Kratz, D. P.; Liu, X.; Lukashin, C.; Mannucci, A. J.; Phojanamongkolkij, N.; Roithmayr, C. M.; Sandford, S.; Taylor, P. C.; Xiong, X.

    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.

  18. 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.

  19. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  20. Response time accuracy in Apple Macintosh computers.

    Science.gov (United States)

    Neath, Ian; Earle, Avery; Hallett, Darcy; Surprenant, Aimée M

    2011-06-01

    The accuracy and variability of response times (RTs) collected on stock Apple Macintosh computers using USB keyboards was assessed. A photodiode detected a change in the screen's luminosity and triggered a solenoid that pressed a key on the keyboard. The RTs collected in this way were reliable, but could be as much as 100 ms too long. The standard deviation of the measured RTs varied between 2.5 and 10 ms, and the distributions approximated a normal distribution. Surprisingly, two recent Apple-branded USB keyboards differed in their accuracy by as much as 20 ms. The most accurate RTs were collected when an external CRT was used to display the stimuli and Psychtoolbox was able to synchronize presentation with the screen refresh. We conclude that RTs collected on stock iMacs can detect a difference as small as 5-10 ms under realistic conditions, and this dictates which types of research should or should not use these systems.

  1. 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...

  2. Accuracy of forecasts in strategic intelligence.

    Science.gov (United States)

    Mandel, David R; Barnes, Alan

    2014-07-29

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

  3. Expected Classification Accuracy using the Latent Distribution

    Directory of Open Access Journals (Sweden)

    Fanmin Guo

    2006-10-01

    Full Text Available Rudner (2001, 2005 proposed a method for evaluating classification accuracy in tests based on item response theory (IRT. In this paper, a latent distribution method is developed. For comparison, both methods are applied to a set of real data from a state test. While the latent distribution method relaxes several of the assumptions needed to apply Rudner's method, both approaches yield extremely comparable results. A simplified approach for applying Rudner's method and a short SPSS routine are presented.

  4. 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

  5. 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

  6. 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.

  7. Algorithms for improving accuracy of spray simulation

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuiYa; ZHANG YuSheng; XIAO HeLin; XU Bo

    2007-01-01

    Fuel spray is the pivotal process of direct injection engine combustion. The accuracy of spray simulation determines the reliability of combustion calculation. However, the traditional techniques of spray simulation in KIVA and commercial CFD codes are very susceptible to grid resolution. As a consequence, predicted engine performance and emission can depend on the computational mesh. The two main causes of this problem are the droplet collision algorithm and coupling between gas and liquid phases. In order to improve the accuracy of spray simulation, the original KIVA code is modified using the cross mesh droplet collision (CMC) algorithm and gas phase velocity interpolation algorithm. In the constant volume apparatus and D.I. Diesel engine, the improvements of the modified KIVA code in spray simulation accuracy are checked from spray structure, predicted average drop size and spray tip penetration, respectively. The results show a dramatic decrease in grid dependency. With these changes, the distorted phenomenon of spray structure is vanished. The uncertainty in predicted average drop size is reduced from 30 to 5 μm in constant volume apparatus calculation, and the uncertainty is further reduced to 2 μm in an engine simulation. The predicted spray tip penetrations in engine simulation also have better consistency in medium and fine meshes.

  8. Computing High Accuracy Power Spectra with Pico

    CERN Document Server

    Fendt, William A

    2007-01-01

    This paper presents the second release of Pico (Parameters for the Impatient COsmologist). Pico is a general purpose machine learning code which we have applied to computing the CMB power spectra and the WMAP likelihood. For this release, we have made improvements to the algorithm as well as the data sets used to train Pico, leading to a significant improvement in accuracy. For the 9 parameter nonflat case presented here Pico can on average compute the TT, TE and EE spectra to better than 1% of cosmic standard deviation for nearly all $\\ell$ values over a large region of parameter space. Performing a cosmological parameter analysis of current CMB and large scale structure data, we show that these power spectra give very accurate 1 and 2 dimensional parameter posteriors. We have extended Pico to allow computation of the tensor power spectrum and the matter transfer function. Pico runs about 1500 times faster than CAMB at the default accuracy and about 250,000 times faster at high accuracy. Training Pico can be...

  9. Accuracy of Stokes integration for geoid computation

    Science.gov (United States)

    Ismail, Zahra; Jamet, Olivier; Altamimi, Zuheir

    2014-05-01

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

  10. Solving Nonlinear Euler Equations with Arbitrary Accuracy

    Science.gov (United States)

    Dyson, Rodger W.

    2005-01-01

    A computer program that efficiently solves the time-dependent, nonlinear Euler equations in two dimensions to an arbitrarily high order of accuracy has been developed. The program implements a modified form of a prior arbitrary- accuracy simulation algorithm that is a member of the class of algorithms known in the art as modified expansion solution approximation (MESA) schemes. Whereas millions of lines of code were needed to implement the prior MESA algorithm, it is possible to implement the present MESA algorithm by use of one or a few pages of Fortran code, the exact amount depending on the specific application. The ability to solve the Euler equations to arbitrarily high accuracy is especially beneficial in simulations of aeroacoustic effects in settings in which fully nonlinear behavior is expected - for example, at stagnation points of fan blades, where linearizing assumptions break down. At these locations, it is necessary to solve the full nonlinear Euler equations, and inasmuch as the acoustical energy is of the order of 4 to 5 orders of magnitude below that of the mean flow, it is necessary to achieve an overall fractional error of less than 10-6 in order to faithfully simulate entropy, vortical, and acoustical waves.

  11. PHAT: PHoto-z Accuracy Testing

    CERN Document Server

    Hildebrandt, H; Capak, P; Moustakas, L A; Wolf, C; Abdalla, F B; Assef, R J; Banerji, M; Benitez, N; Brammer, G B; Budavari, T; Carliles, S; Coe, D; Dahlen, T; Feldmann, R; Gerdes, D; Gillis, B; Ilbert, O; Kotulla, R; Lahav, O; Li, I H; Miralles, J -M; Purger, N; Schmidt, S; Singal, J

    2010-01-01

    Here we introduce PHAT, the PHoto-z Accuracy Testing programme, an international initiative to test and compare different methods of photo-z estimation. Two different test environments are set up, one (PHAT0) based on simulations to test the basic functionality of the different photo-z codes, and another one (PHAT1) based on data from the GOODS survey. The accuracy of the different methods is expressed and ranked by the global photo-z bias, scatter, and outlier rates. Most methods agree well on PHAT0 but produce photo-z scatters that can differ by up to a factor of two even in this idealised case. A larger spread in accuracy is found for PHAT1. Few methods benefit from the addition of mid-IR photometry. Remaining biases and systematic effects can be explained by shortcomings in the different template sets and the use of priors on the one hand and an insufficient training set on the other hand. Scatters of 4-8% in Delta_z/(1+z) were obtained, consistent with other studies. However, somewhat larger outlier rate...

  12. Species comparison of protein synthesis accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, G.P.; Popp, R.A.; Francis, M.C.; Bradshaw, B.S.; Bailiff, E.G.

    1978-01-01

    An important force in evolutionary selection may be informational efficiency, which results in a balance between the energy expended to maintain a high level of fidelity and the energy lost from errors or mutations in the production of defective offspring. The accuracy of DNA replication may be limited by the average accuracy of protein synthesis if the major source of enzymes which make copying errors are those that contain errors resulting from the processes of transcription and translation. Since many gene products are involved in transcription and translation the frequency of mutations which might affect protein fidelity is much higher than those affecting DNA copying. Species comparisons were made of the accuracy of protein synthesis to determine if the requirements for accurate protein synthesis were more stringent for long lived mammals. Using the incorporation of isoleucine in hemoglobin chains which contain no genetically coded isoleucine as a test of protein synthesis fidelity no correlation with lifespan was found among rabbit, marmoset, cow, pig, and human protein synthesis fidelity. The purfication techniques required to prepare highly purified protein for analysis and the criteria for purity are described.

  13. Speed versus accuracy in collective decision making.

    Science.gov (United States)

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

    2003-12-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  15. Diagnostic accuracy of Focused Abdominal Sonography

    Directory of Open Access Journals (Sweden)

    Cheung Kent Shek

    2012-11-01

    Full Text Available 【Abstract】Objective: Focused Abdominal Sono-graphy for Trauma (FAST is widely used for the detection of intraperitoneal free fluids in patients suffering from blunt abdominal trauma (BAT. This study aimed at assessing the diagnostic accuracy of this investigation in a designated trauma centre. Methods: This was a retrospective study of BAT pa-tients over a 6 year period seen in a trauma centre in Hong Kong. FAST findings were compared with laparotomy, ab-dominal computed tomography or autopsy findings, which served as the gold standard for presence of intraperi-toneal free fluids. The patients who did not have FAST or gold standard confirmatory test performed, had preexisting peritoneal fluid, died at resuscitation or had imcomplete docu-mentation of FAST findings were excluded. The performance of FAST was expressed as sensitivity, specificity, predic-tive values (PV, likelihood ratios (LR and accuracy. Results: FAST was performed in 302 patients and 153 of them were included in this analysis. The sensitivity, specificity, positive PV, negative PV, positive LR, negative LR and accuracy for FAST were respectively 50.0%, 97.3%, 87.0%, 84.6%, 18.8, 0.5 and 85.0%. FAST was found to be more sensitive in less severely injured patients and more specific in more severely injured patients. Conclusion: FAST is a reliable investigation in the initial assessment of BAT patients. The diagnostic values of FAST could be affected by the severity of injury and staff training is needed to further enhance its effective use. Key words: Laparotomy; Autopsy; Tomography, X-ray computed; Tomography, spiral computed; Ultra-sonography

  16. Accuracy and precision of an IGRT solution.

    Science.gov (United States)

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

    2009-01-01

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

  17. 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...

  18. Accuracy of MR in growth plate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Shiguetomi-Medina, Juan Manuel [Aarhus University, Orthopaedic Research Laboratory, Aarhus University Hospital NBG, Aarhus C (Denmark); Rahbek, Ole [Aarhus University Hospital NBG, Department of Children' s Orthopaedics, Aarhus C (Denmark); Ringgaard, Steffen; Kristiansen, Maja Sofie; Stoedkilde-Joergensen, Hans [Aarhus University Hospital, Skejby, The MR Research Center, Aarhus N (Denmark); Moeller-Madsen, Bjarne [Aarhus University, Orthopaedic Research Laboratory, Aarhus University Hospital NBG, Aarhus C (Denmark); Aarhus University Hospital NBG, Department of Children' s Orthopaedics, Aarhus C (Denmark)

    2014-09-15

    To analyze the accuracy of growth-plate thickness measurements detected on 1.5-T and 7-T MR images using histology sections as a standard of reference. Four defrosted pig tibiae were 1.5-T MR scanned and one fresh tibia was 7-T MR scanned. The height of the growth plate was measured and compared to histology. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7-T MR images was 465 μm (SD = 62.2) and 1,325 μm (SD = 183.5) on 1.5-T MR measurements. We found a better correspondence between the growth plate thickness measured on the 7-T MR and histology samples compared to 1.5 T. The growth plate can be identified and measured with high accuracy using 7-T MR. 1.5-T MR can only describe some morphological characteristics. (orig.)

  19. The IBIS / ISGRI Source Location Accuracy

    CERN Document Server

    Gros, A; Soldi, S; Gotz, D; Caballero, I; Mattana, F; Heras, J A Zurita

    2013-01-01

    We present here results on the source location accuracy of the INTEGRAL IBIS/ISGRI coded mask telescope, based on ten years of INTEGRAL data and on recent developments in the data analysis procedures. Data were selected and processed with the new Off-line Scientific Analysis pipeline (OSA10.0) that benefits from the most accurate background corrections, the most performing coding noise cleaning and sky reconstruction algorithms available. We obtained updated parameters for the evaluation of the point source location error from the source signal to noise ratio. These results are compared to previous estimates and to theoretical expectations. Also thanks to a new fitting procedure the typical error at 90% confidence level for a source at a signal to noise of 10 is now estimated to be 1.5 arcmin. Prospects for future analysis on the Point Spread Function fitting procedure and on the evaluation of residual biases are also presented. The new consolidated parameters describing the source location accuracy that will...

  20. Curation accuracy of model organism databases.

    Science.gov (United States)

    Keseler, Ingrid M; Skrzypek, Marek; Weerasinghe, Deepika; Chen, Albert Y; Fulcher, Carol; Li, Gene-Wei; Lemmer, Kimberly C; Mladinich, Katherine M; Chow, Edmond D; Sherlock, Gavin; Karp, Peter D

    2014-01-01

    Manual extraction of information from the biomedical literature-or biocuration-is the central methodology used to construct many biological databases. For example, the UniProt protein database, the EcoCyc Escherichia coli database and the Candida Genome Database (CGD) are all based on biocuration. Biological databases are used extensively by life science researchers, as online encyclopedias, as aids in the interpretation of new experimental data and as golden standards for the development of new bioinformatics algorithms. Although manual curation has been assumed to be highly accurate, we are aware of only one previous study of biocuration accuracy. We assessed the accuracy of EcoCyc and CGD by manually selecting curated assertions within randomly chosen EcoCyc and CGD gene pages and by then validating that the data found in the referenced publications supported those assertions. A database assertion is considered to be in error if that assertion could not be found in the publication cited for that assertion. We identified 10 errors in the 633 facts that we validated across the two databases, for an overall error rate of 1.58%, and individual error rates of 1.82% for CGD and 1.40% for EcoCyc. These data suggest that manual curation of the experimental literature by Ph.D-level scientists is highly accurate. Database URL: http://ecocyc.org/, http://www.candidagenome.org//

  1. Enhancing Accuracy of Plant Leaf Classification Techniques

    Directory of Open Access Journals (Sweden)

    C. S. Sumathi

    2014-03-01

    Full Text Available Plants have become an important source of energy, and are a fundamental piece in the puzzle to solve the problem of global warming. Living beings also depend on plants for their food, hence it is of great importance to know about the plants growing around us and to preserve them. Automatic plant leaf classification is widely researched. This paper investigates the efficiency of learning algorithms of MLP for plant leaf classification. Incremental back propagation, Levenberg–Marquardt and batch propagation learning algorithms are investigated. Plant leaf images are examined using three different Multi-Layer Perceptron (MLP modelling techniques. Back propagation done in batch manner increases the accuracy of plant leaf classification. Results reveal that batch training is faster and more accurate than MLP with incremental training and Levenberg– Marquardt based learning for plant leaf classification. Various levels of semi-batch training used on 9 species of 15 sample each, a total of 135 instances show a roughly linear increase in classification accuracy.

  2. Approaching Chemical Accuracy with Quantum Monte Carlo

    CERN Document Server

    Petruzielo, F R; Umrigar, C J

    2012-01-01

    A quantum Monte Carlo study of the atomization energies for the G2 set of molecules is presented. Basis size dependence of diffusion Monte Carlo atomization energies is studied with a single determinant Slater-Jastrow trial wavefunction formed from Hartree-Fock orbitals. With the largest basis set, the mean absolute deviation from experimental atomization energies for the G2 set is 3.0 kcal/mol. Optimizing the orbitals within variational Monte Carlo improves the agreement between diffusion Monte Carlo and experiment, reducing the mean absolute deviation to 2.1 kcal/mol. Moving beyond a single determinant Slater-Jastrow trial wavefunction, diffusion Monte Carlo with a small complete active space Slater-Jastrow trial wavefunction results in near chemical accuracy. In this case, the mean absolute deviation from experimental atomization energies is 1.2 kcal/mol. It is shown from calculations on systems containing phosphorus that the accuracy can be further improved by employing a larger active space.

  3. 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...... shutter is controlled in steps of 100 ps. Camera delay is controlled in steps of 100 ps. Each laser pulse triggers the camera delay and shutter. A 3-D image is constructed from a sequence of 50-100 2-D reflectivity images, where each frame integrates about 700 laser pulses on the CCD. In 50 Hz video mode...

  4. On the accuracy of the Debye shielding

    CERN Document Server

    Martínez-Fuentes, M A

    2012-01-01

    The expression for the Debye shielding in plasma physics is usually derived under the assumptions that the plasma particles are weakly coupled, so their kinetic energy is much larger than the potential energy between them, and that the velocity distributions of the plasma species are Maxwellian. The first assumption also establishes that the plasma parameter ND, the number of particles within a sphere with a Debye radius should be greater than 1, and determines the difference between weakly and strongly coupled plasmas. Under such assumptions, Poisson's equation can be linearised, and a simple analytic expression obtained for the electrostatic potential. However, textbooks rarely discuss the accuracy of this approximation. In this work we compare the linearised solution with the exact one, obtained numerically, and show that the linearisation, which underestimates the exact solution, is reasonably good even for ND ~ 40. We give quantitative criteria to set the limit of the approximation when the number of par...

  5. Stereotype accuracy of ballet and modern dancers.

    Science.gov (United States)

    Clabaugh, Alison; Morling, Beth

    2004-02-01

    The authors recorded preprofessional ballet and modern dancers' perceptions of the personality traits of each type of dancer and self-reports of their own standing, to test the accuracy of the group stereotypes. Participants accurately stereotyped ballet dancers as scoring higher than modern dancers on Fear of Negative Evaluation and Personal Need for Structure and accurately viewed the groups as equal on Fitness Esteem. Participants inaccurately stereotyped ballet dancers as lower on Body Esteem; the groups actually scored the same. Sensitivity correlations across traits indicated that dancers were accurate about the relative magnitudes of trait differences in the two types of dancers. A group of nondancers reported stereotypes that were usually in the right direction although of inaccurate magnitude, and nondancers were sensitive to the relative sizes of group differences across traits.

  6. 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.

  7. Accuracy analysis of a spectral Poisson solver

    Energy Technology Data Exchange (ETDEWEB)

    Rambaldi, S. [Dipartimento di Fisica Universita di Bologna and INFN, Bologna, Via Irnerio 46, 40126 (Italy)]. E-mail: rambaldi@bo.infn.it; Turchetti, G. [Dipartimento di Fisica Universita di Bologna and INFN, Bologna, Via Irnerio 46, 40126 (Italy); Benedetti, C. [Dipartimento di Fisica Universita di Bologna and INFN, Bologna, Via Irnerio 46, 40126 (Italy); Mattioli, F. [Dipartimento di Fisica Universita di Bologna, Bologna, Via Irnerio 46, 40126 (Italy); Franchi, A. [GSI, Darmstadt, Planckstr. 1, 64291 (Germany)

    2006-06-01

    We solve Poisson's equation in d=2,3 space dimensions by using a spectral method based on Fourier decomposition. The choice of the basis implies that Dirichlet boundary conditions on a box are satisfied. A Green's function-based procedure allows us to impose Dirichlet conditions on any smooth closed boundary, by doubling the computational complexity. The error introduced by the spectral truncation and the discretization of the charge distribution is evaluated by comparison with the exact solution, known in the case of elliptical symmetry. To this end boundary conditions on an equipotential ellipse (ellipsoid) are imposed on the numerical solution. Scaling laws for the error dependence on the number K of Fourier components for each space dimension and the number N of point charges used to simulate the charge distribution are presented and tested. A procedure to increase the accuracy of the method in the beam core region is briefly outlined.

  8. Improved accuracy in nano beam electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Beche, A; Rouviere, J-L [CEA, INAC, SP2M, LEMMA, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Clement, L, E-mail: armand.beche@cea.f, E-mail: jean-luc.rouviere@cea.f [ST Microelectronics, 850 rue Jean Monnet, F-38920 Crolles (France)

    2010-02-01

    Nano beam electron diffraction (NBD or NBED) is applied on a well controlled sample in order to evaluate the limit of the technique to measure strain. Measurements are realised on a 27nm thick Si{sub 0.7}Ge{sub 0.3} layer embedded in a silicon matrix, with a TITAN microscope working at 300kV. Using a standard condenser aperture of 50{mu}m, a probe size diameter of 2.7 nm is obtained and a strain accuracy of 6x10{sup -4} (mean root square, rms) is achieved. NBED patterns are acquired along a [110] direction and the bidimensionnal strain in the (110) plane is measured. Finite element simulations are carried out to check experimental results and reveal that strain relaxation and probe averaging in a 170nm thick TEM lamella reduces strain by 15%.

  9. Moyamoya disease: diagnostic accuracy of MRI.

    Science.gov (United States)

    Yamada, I; Suzuki, S; Matsushima, Y

    1995-07-01

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

  10. 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.

  11. Human Speed-Accuracy Tradeoffs in Search

    CERN Document Server

    Aperjis, Christina; Wu, Fang

    2010-01-01

    When foraging for information, users face a tradeoff between the accuracy and value of the acquired information and the time spent collecting it, a problem which also surfaces when seeking answers to a question posed to a large community. We empirically study how people behave when facing these conflicting objectives using data from Yahoo Answers, a community driven question-and-answer site. We first study how users behave when trying to maximize the amount of acquired information while minimizing the waiting time. We find that users are willing to wait longer for an additional answer if they have received a small number of answers. We then assume that users make a sequence of decisions, deciding to wait for an additional answer as long as the quality of the current answer exceeds some threshold. The resulting probability distribution for the number of answers that a question gets is an inverse Gaussian, a fact that is validated by our data.

  12. Prognostic Accuracy of Electroencephalograms in Preterm Infants

    DEFF Research Database (Denmark)

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

    2017-01-01

    (267 infants). Any aEEG background abnormality was a predictor of abnormal outcome. For prediction of a developmental quotient ...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...

  13. 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...

  14. Accuracy of the vivofit activity tracker.

    Science.gov (United States)

    Alsubheen, Sana'a A; George, Amanda M; Baker, Alicia; Rohr, Linda E; Basset, Fabien A

    2016-08-01

    The purpose of this study was to examine the accuracy of the vivofit activity tracker in assessing energy expenditure and step count. Thirteen participants wore the vivofit activity tracker for five days. Participants were required to independently perform 1 h of self-selected activity each day of the study. On day four, participants came to the lab to undergo BMR and a treadmill-walking task (TWT). On day five, participants completed 1 h of office-type activities. BMR values estimated by the vivofit were not significantly different from the values measured through indirect calorimetry (IC). The vivofit significantly underestimated EE for treadmill walking, but responded to the differences in the inclination. Vivofit underestimated step count for level walking but provided an accurate estimate for incline walking. There was a strong correlation between EE and the exercise intensity. The vivofit activity tracker is on par with similar devices and can be used to track physical activity.

  15. Dosimetric accuracy of a staged radiosurgery treatment

    Science.gov (United States)

    Cernica, George; de Boer, Steven F.; Diaz, Aidnag; Fenstermaker, Robert A.; Podgorsak, Matthew B.

    2005-05-01

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  16. Dosimetric accuracy of a staged radiosurgery treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cernica, George [Department of Physics, State University of New York at Buffalo, Buffalo, NY 14263 (United States); Boer, Steven F de [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Diaz, Aidnag [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Fenstermaker, Robert A [Department of Neurosurgery, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Podgorsak, Matthew B [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States)

    2005-05-07

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  17. 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

  18. Accuracy of anemia diagnosis by physical examination

    Directory of Open Access Journals (Sweden)

    Isabela Martins Benseñor

    Full Text Available CONTEXT AND OBJECTIVES: Quantification of clinical signs such as the presence or absence of pallor at clinical examination is a key step for making diagnoses. The aim was, firstly, to evaluate two methods for anemia diagnosis by physical examination: four-level evaluation (crosses method: +/++/+++/++++ and estimated hemoglobin values, both performed by medical students and staff physicians; and secondly, to investigate whether there was any improvement in assessment accuracy according to the number of years in clinical practice. DESIGN AND SETTING: Forty-four randomly selected physicians and medical students in a tertiary care teaching hospital completed a physical examination on five patients with mild to severe anemia. METHODS: The observers used four-level evaluation and also predicted the hemoglobin level. Both methods were compared with the real hemoglobin value as the gold standard. RESULTS: The mean estimated hemoglobin value correlated better with the real hemoglobin values than did the four-level evaluation method, for attending physicians, residents and students (Spearman's correlation coefficients, respectively: 1.0, 1.0 and 0.9 for guessed hemoglobin and -0.8, -0.8 and -0.7 for the four-level evaluation method. There were no differences in the mean "guessed" hemoglobin values from attending physicians, residents and students. However, the correlation between guessed hemoglobin value and the four-level method was positive for attending physicians, thus suggesting some kind of improvement with time (p = 0.04. CONCLUSIONS: This study showed that estimated hemoglobin was more accurate than evaluation by the four-level method. The number of years in clinical practice did not improve the accuracy of clinical examination for anemia.

  19. Methodology for high accuracy contact angle measurement.

    Science.gov (United States)

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

    2009-12-15

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

  20. Improving the accuracy of death certification

    Science.gov (United States)

    Myers, K A; Farquhar, D R

    1998-01-01

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

  1. A SINGLE STEP SCHEME WITH HIGH ACCURACY FOR PARABOLIC PROBLEM

    Institute of Scientific and Technical Information of China (English)

    陈传淼; 胡志刚

    2001-01-01

    A single step scheme with high accuracy for solving parabolic problem is proposed. It is shown that this scheme possesses good stability and fourth order accuracy with respect to both time and space variables, which are superconvergent.

  2. Accuracy Assessment Points for Tuzigoot National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in May, 1997 to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS Vegetation...

  3. Accuracy Assessment Points for Voyageurs National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Thematic accuracy requirements for the USGS-NPS Vegetation Mapping Program specify 80% accuracy for each map unit that represents USNVC floristic types. A total of...

  4. IMPROVED ACCURACY AND ROUGHNESS MEASURES FOR ROUGH SETS

    Institute of Scientific and Technical Information of China (English)

    Zhou Yuming; Xu Baowen

    2002-01-01

    Accuracy and roughness, proposed by Pawlak(1982), might draw a conclusion inconsistent with our intuition in some cases. This letter analyzes the limitations in these measures and proposes improved accuracy and roughness measures based on information theory.

  5. 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.

  6. Dimensional accuracy of thermoformed polymethyl methacrylate.

    Science.gov (United States)

    Jagger, R G

    1996-12-01

    Thermoforming of polymethyl methacrylate sheet is used to produce a number of different types of dental appliances. The purpose of this study was to determine the dimensional accuracy of thermoformed polymethyl methacrylate specimens. Five blanks of the acrylic resin were thermoformed on stone casts prepared from a silicone mold of a brass master die. The distances between index marks were measured both on the cast and on the thermoformed blanks with an optical comparator. Measurements on the blanks were made again 24 hours after processing and then 1 week, 1 month, and 3 months after immersion in water. Linear shrinkage of less than 1% (range 0.37% to 0.52%) was observed 24 hours after removal of the blanks from the cast. Immersion of the thermoformed specimens in water resulted in an increase in measured dimensions, but after 3 months' immersion these increases were still less than those of the cast (range 0.07% to 0.18%). It was concluded that it is possible to thermoform Perspex polymethyl methacrylate accurately.

  7. Accuracy and robustness evaluation in stereo matching

    Science.gov (United States)

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

    2016-09-01

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

  8. Navigation in Orthognathic Surgery: 3D Accuracy.

    Science.gov (United States)

    Badiali, Giovanni; Roncari, Andrea; Bianchi, Alberto; Taddei, Fulvia; Marchetti, Claudio; Schileo, Enrico

    2015-10-01

    This article aims to determine the absolute accuracy of maxillary repositioning during orthognathic surgery according to simulation-guided navigation, that is, the combination of navigation and three-dimensional (3D) virtual surgery. We retrospectively studied 15 patients treated for asymmetric dentofacial deformities at the Oral and Maxillofacial Surgery Unit of the S.Orsola-Malpighi University Hospital in Bologna, Italy, from January 2010 to January 2012. Patients were scanned with a cone-beam computed tomography before and after surgery. The virtual surgical simulation was realized with a dedicated software and loaded on a navigation system to improve intraoperative reproducibility of the preoperative planning. We analyzed the outcome following two protocols: (1) planning versus postoperative 3D surface analysis; (2) planning versus postoperative point-based analysis. For 3D surface comparison, the mean Hausdorff distance was measured, and median among cases was 0.99 mm. Median reproducibility orthognathic surgery, if compared with the surgical computer-designed project realized with a dedicated software, particularly for the vertical dimension, which is the most challenging to manage.

  9. Firing temperature accuracy of four dental furnaces.

    Science.gov (United States)

    Haag, Per; Ciber, Edina; Dérand, Tore

    2011-01-01

    In spite of using recommended firing and displayed temperatures, low-fired dental porcelain more often demonstrates unsatisfactory results after firing than porcelain fired at higher temperatures. It could therefore be anticipated that temperatures shown on the display are incorrect, implying that the furnace does not render correct firing programs for low-fired porcelain. The purpose of this study is to investigate deviations from the real temperature during the firing process and also to illustrate the service and maintenance discipline of furnaces at dental laboratories. Totally 20 units of four different types of dental furnaces were selected for testing of temperature accuracy with usage of a digital temperature measurement apparatus, Therma 1. In addition,the staffs at 68 dental laboratories in Sweden were contacted for a telephone interview on furnace brand and on service and maintenance program performed at their laboratories. None of the 20 different dental furnaces in the study could generate the firing temperatures shown on the display, indicating that the hypothesis was correct. Multimat MCII had the least deviation of temperature compared with displayfigures. 62 out of 68 invited dental laboratories chose to participate in the interviews and the result was that very few laboratories had a service and maintenance program living up to quality standards. There is room for improving the precision of dental porcelain furnaces as there are deviations between displayed and read temperatures during the different steps of the firing process.

  10. [Accuracy of a pulse oximeter during hypoxia].

    Science.gov (United States)

    Tachibana, C; Fukada, T; Hasegawa, R; Satoh, K; Furuya, Y; Ohe, Y

    1996-04-01

    The accuracy of the pulse oximeter was examined in hypoxic patients. We studied 11 cyanotic congenital heart disease patients during surgery, and compared the arterial oxygen saturation determined by both the simultaneous blood gas analysis (CIBA-CORNING 288 BLOOD GAS SYSTEM, SaO2) and by the pulse oximeter (DATEX SATELITE, with finger probe, SpO2). Ninty sets of data on SpO2 and SaO2 were obtained. The bias (SpO2-SaO2) was 1.7 +/- 6.9 (mean +/- SD) %. In cyanotic congenital heart disease patients, SpO2 values were significantly higher than SaO2. Although the reason is unknown, in constantly hypoxic patients, SpO2 values are possibly over-estimated. In particular, pulse oximetry at low levels of saturation (SaO2 below 80%) was not as accurate as at a higher saturation level (SaO2 over 80%). There was a positive correlation between SpO2 and SaO2 (linear regression analysis yields the equation y = 0.68x + 26.0, r = 0.93). In conclusion, the pulse oximeter is useful to monitor oxygen saturation in constantly hypoxic patients, but the values thus obtained should be compared with the values measured directly when hypoxemia is severe.

  11. Accuracy estimation of foamy virus genome copying

    Directory of Open Access Journals (Sweden)

    Rethwilm Axel

    2009-04-01

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

  12. 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

  13. Influence of Exposure Time on Prototyping Accuracy in Stereolithography

    Institute of Scientific and Technical Information of China (English)

    吴懋亮; 方明伦; 胡庆夕; 戴春祥; 卢秉恒

    2004-01-01

    A novel stereolithgraphy system with conventional UV light as a light source uses the 2D worktable as moving components,whose characteristics determine the accuracy of the prototyping parts. Many factors including mass of the worktable, elasticity and damp coefficients, speed and acceleration affect the non-uniform exposure time of the resin, and eventually influence the cured line shape and the curing accuracy. A light shuttle is used to eliminate the cure errors, greatly improving accuracy of the parts.

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

    Science.gov (United States)

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

    2016-10-01

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

  15. Virtual Teaching Simulation for Robot Assembly Accuracy Analysis

    Institute of Scientific and Technical Information of China (English)

    张征; 周宏甫; 刘斌

    2004-01-01

    In this paper, by teaching a 3D robot unit model and playing back to simulate the assembly process in a virtual assembly environment, errors in robot assembly are analyzed. The paper also presents a visualization method for analyzing accuracy of the robot assembly, and studies the influence of the spatial pose of a robot on the success rate of an axis-hole assembly, and accuracy of the robot teaching program in particular. Through integration of various errors and on the basis of assembly accuracy, tolerance of error sources can be reasonably distributed to meet the assembly accuracy requirement, therefore the planning of robot assembly unit can be improved.

  16. Students' Accuracy of Measurement Estimation: Context, Units, and Logical Thinking

    Science.gov (United States)

    Jones, M. Gail; Gardner, Grant E.; Taylor, Amy R.; Forrester, Jennifer H.; Andre, Thomas

    2012-01-01

    This study examined students' accuracy of measurement estimation for linear distances, different units of measure, task context, and the relationship between accuracy estimation and logical thinking. Middle school students completed a series of tasks that included estimating the length of various objects in different contexts and completed a test…

  17. Accuracy analysis of the part made by selected laser sintering

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The effects of different factors, including the precision of selected laser sintering (SLS) equipment, sintering temperature, sintered thickness of individual layer and laser scanning route, on the SLS part accuracy have been analyzed and studied. Some measures are suggested in order to improve the part accuracy made by SLS.

  18. 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...

  19. Understanding the Delayed-Keyword Effect on Metacomprehension Accuracy

    Science.gov (United States)

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

    2005-01-01

    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.…

  20. 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…

  1. Diagnostic methods I: sensitivity, specificity, and other measures of accuracy

    NARCIS (Netherlands)

    K.J. van Stralen; V.S. Stel; J.B. Reitsma; F.W. Dekker; C. Zoccali; K.J. Jager

    2009-01-01

    For most physicians, use of diagnostic tests is part of daily routine. This paper focuses on their usefulness by explaining the different measures of accuracy, the interpretation of test results, and the implementation of a diagnostic strategy. Measures of accuracy include sensitivity and specificit

  2. Prediction of Rate Constants for Catalytic Reactions with Chemical Accuracy.

    Science.gov (United States)

    Catlow, C Richard A

    2016-08-01

    Ex machina: A computational method for predicting rate constants for reactions within microporous zeolite catalysts with chemical accuracy has recently been reported. A key feature of this method is a stepwise QM/MM approach that allows accuracy to be achieved while using realistic models with accessible computer resources.

  3. Accuracy of depth of cut in micro milling operations

    DEFF Research Database (Denmark)

    Bissacco, Giuliano

    In any kind of conventional machining operation, dimensional and geometrical accuracy of the machined part cannot be achieved without a precise control of cutting parameters as well as positioning accuracy. Miniaturization of components implies a reduction of all component’s dimensions and involv...

  4. Clock accuracy analysis for a coherent IR-UWB system

    NARCIS (Netherlands)

    Wang, X.; Young, A.; Philips, K.; Groot, H. de

    2011-01-01

    The performance of a duty-cycled coherent impulse radio UWB system is typically dominated by the accuracy of its timing references. In this paper, a timing analysis is presented for an IR-UWB system to specify the accuracy requirements for the internal clocks of the transceiver. A possible clock gen

  5. Accuracy of References in Ten Library Science Journals.

    Science.gov (United States)

    Pope, Nancy N.

    1992-01-01

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

  6. Camera Calibration Accuracy at Different Uav Flying Heights

    Science.gov (United States)

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

    2017-02-01

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

  7. 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.

  8. Improving metacomprehension accuracy in an undergraduate course context.

    Science.gov (United States)

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

    2016-12-01

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

  9. Assessing and Ensuring GOES-R Magnetometer Accuracy

    Science.gov (United States)

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

    2016-01-01

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

  10. The accuracy assessment in areal interpolation:An empirical investigation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Areal interpolation is the process of transferring data from source zones to target zones. While method development remains a top research priority in areal interpo-lation,the accuracy assessment aspect also begs for attention. This paper reports an empirical experience on probing an areal interpolation method to highlight the power and potential pitfalls in accuracy assessment. A kriging-based interpolation algorithm is evaluated by several approaches. It is found that accuracy assessment is a powerful tool to understand an interpolation method,e.g. the utility of ancillary data and semi-variogram modeling in kriging in our case study. However,different assessment methods and spatial units on which assessment is conducted can lead to rather different results. The typical practice to assess accuracy at the source zone level may overestimate interpolation accuracy. Assessment at the target zone level is suggested as a supplement.

  11. Recognition accuracy by experienced men and women players of basketball.

    Science.gov (United States)

    Millslagle, Duane G

    2002-08-01

    This study examined 30 experienced basketball players' recognition accuracy by sex, playing position (guard, forward, and center), and situations in the game of basketball. The study used a perceptual cognitive paradigm in which subjects viewed slides of structured and unstructured game situations and accurately recognized the presence or absence of the basketball. A significant difference in recognition accuracy by sex, players' position, and structure of the game situation was found. Male players' recognition accuracy was better than the female players'. The recognition accuracy of subjects who played guard was better than that of subjects who played forward or center. The players' recognition accuracy was more accurate when observing structured plays versus unstructured plays. The conclusion of this study suggested that experienced basketball players differ in their cognitive and visual searching processes by sex and player position within the sport of basketball.

  12. 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.

  13. Accuracy Assessment of Coastal Topography Derived from Uav Images

    Science.gov (United States)

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

    2016-06-01

    To monitor coastal environments, Unmanned Aerial Vehicle (UAV) is a low-cost and easy to use solution to enable data acquisition with high temporal frequency and spatial resolution. Compared to Light Detection And Ranging (LiDAR) or Terrestrial Laser Scanning (TLS), this solution produces Digital Surface Model (DSM) with a similar accuracy. To evaluate the DSM accuracy on a coastal environment, a campaign was carried out with a flying wing (eBee) combined with a digital camera. Using the Photoscan software and the photogrammetry process (Structure From Motion algorithm), a DSM and an orthomosaic were produced. Compared to GNSS surveys, the DSM accuracy is estimated. Two parameters are tested: the influence of the methodology (number and distribution of Ground Control Points, GCPs) and the influence of spatial image resolution (4.6 cm vs 2 cm). The results show that this solution is able to reproduce the topography of a coastal area with a high vertical accuracy (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.

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

    Science.gov (United States)

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

    2016-06-22

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

  15. 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.

  16. Research on techniques to improve accuracy in SBL locating systems

    Institute of Scientific and Technical Information of China (English)

    SHI Jie; LIU Bo-sheng; SONG Hai-yan

    2008-01-01

    Short baseline system (SBL), which is a kind of underwater acoustic locating technology, has widely applicable value. In order to examine the capability of ship model design, the ship model experimentation should have high accuracy. This paper focuses on the key techniques of high accuracy locating system, including high accuracy sub-array position emendation, divisional locating, anti multi-path interference measure, etc. Experiments show that the SBL locating systems has received the satisfying effect owing to these key techniques proposed in this paper.

  17. [Design and accuracy analysis of upper slicing system of MSCT].

    Science.gov (United States)

    Jiang, Rongjian

    2013-05-01

    The upper slicing system is the main components of the optical system in MSCT. This paper focuses on the design of upper slicing system and its accuracy analysis to improve the accuracy of imaging. The error of slice thickness and ray center by bearings, screw and control system were analyzed and tested. In fact, the accumulated error measured is less than 1 microm, absolute error measured is less than 10 microm. Improving the accuracy of the upper slicing system contributes to the appropriate treatment methods and success rate of treatment.

  18. ACCURACY ANALYSIS OF PASSIVE LOCATION SYSTEMWITH PHASE DIFFERENCE RATE MEASUREMENT

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The conventional mono-station passive location techniques of direction finding are low in speed and accuracy. It may not meet the requirements of modern targeting or accuracy attacking actions. For a moving observer, by employing some passive measurements such as Doppler or Phase Difference Rate (PDR), the location error can be reduced to nearly one-fifth of the conventional error[1~4].  In this paper, the location method using PDR is introduced in section one. Location accuracy analysis is given in section two. Simulation results of error's lower bound of 3D location are produced in section four. Finally, the conclusion is presented in section five.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-06-22

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

  20. Inertial measures of motion for clinical biomechanics: comparative assessment of accuracy under controlled conditions - changes in accuracy over time.

    Directory of Open Access Journals (Sweden)

    Karina Lebel

    Full Text Available 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.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.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.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.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 full potential in capturing clinical outcomes.

  1. 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...... was analyzed in both superior and inferior maxillary repositioning. In addition, transverse surgical expansion was compared with the postsurgical expansion obtained. An overall, high degree of linear accuracy between planned and postsurgical outcomes was found, but with a large standard deviation. Rotational...

  2. Accelerating scientific codes by performance and accuracy modeling

    CERN Document Server

    Fabregat-Traver, Diego; Bientinesi, Paolo

    2016-01-01

    Scientific software is often driven by multiple parameters that affect both accuracy and performance. Since finding the optimal configuration of these parameters is a highly complex task, it extremely common that the software is used suboptimally. In a typical scenario, accuracy requirements are imposed, and attained through suboptimal performance. In this paper, we present a methodology for the automatic selection of parameters for simulation codes, and a corresponding prototype tool. To be amenable to our methodology, the target code must expose the parameters affecting accuracy and performance, and there must be formulas available for error bounds and computational complexity of the underlying methods. As a case study, we consider the particle-particle particle-mesh method (PPPM) from the LAMMPS suite for molecular dynamics, and use our tool to identify configurations of the input parameters that achieve a given accuracy in the shortest execution time. When compared with the configurations suggested by exp...

  3. 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...

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

    Science.gov (United States)

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

    2009-01-01

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

  5. On the accuracy of recent Goddard gravity models

    Science.gov (United States)

    Lerch, F. J.; Klosko, S. M.; Wagner, C. A.; Patel, G. B.

    1985-01-01

    The Goddard Space Flight Center (GSFC) has occupied a central position within NASA with respect to the development of earth gravity models. The gravity models at Goddard, which are referred to as the Goddard earth models (GEM's) have been under development for more than 15 years. The fields have increased in size and (apparent) accuracy with the inclusion of new tracking data, better nongravitational force modeling, and more orbits over a wide range of inclinations and mean motions. The usefulness of the considered models depends largely on accuracy estimates. The present paper is concerned with a reevaluation of earlier accuracy assessments, taking into account the accuracies of the GEM 9 and the GEM-L2 models. It is found that GEM 9 is about 30 percent more accurate than originally estimated in 1979 from older gravimetry data.

  6. Accuracy Assessment Points for Petersburg National Battlefield Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile depicts the locations of thematic accuracy assessment sampling points used in the vegetation mapping of Petersburg National Battlefield. It was...

  7. Accuracy Assessment Points for Badlands National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This metadata is for the accuracy assessment data associated with the vegetation land cover and land use geospatial database for Badlands National Park and...

  8. Accuracy Assessment Points for Dinosaur National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This point file displays the 1543 accuracy assessment (AA) points visited in the summer of 2005 as part of the vegetation mapping project. The points were randomly...

  9. Accuracy of spinal navigation for Magerl-screws

    CERN Document Server

    Herz, T

    2001-01-01

    Study design: assessment of the accuracy of frameless stereotactic navigation at the second cervical vertebra. Objectives: to assess the influence of the protocol of preoperative CT-scan and the registration technique on the accuracy of navigation for implanting Magerl-screws. Summary of background data: the use of navigation systems for implanting Magerl-screws could help to decrease the risk of complications and to reduce the required skin incision. Two parameters conceivably affecting the accuracy are the protocol of the preoperative CT-scan and the registration technique. Methods: four cervical spine segments of human cadavers were scanned with two different protocols (3 mm slice thickness/2 mm table increment, 1 mm slice thickness/1 mm table increment). Registration was performed either based on anatomical landmarks or using a specially designed percutaneous registration device. For the accuracy-check, the pointer tip was exactly placed on markers. The distance between the pointer and the marker displaye...

  10. Rasch modeling of accuracy and confidence measures from cognitive tests.

    Science.gov (United States)

    Paek, Insu; Lee, Jihyun; Stankov, Lazar; Wilson, Mark

    2013-01-01

    The use of IRT models has not been rigorously applied in studies of the relationship between test-takers' confidence and accuracy. This study applied the Rasch measurement models to investigate the relationship between test-takers' confidence and accuracy on English proficiency tests, proposing potentially useful measures of under or overconfidence. The Rasch approach provided the scaffolding to formulate indices that can assess the discrepancy between confidence and accuracy at the item or total test level, as well as at particular ability levels locally. In addition, a "disattenuated" measure of association between accuracy and confidence, which takes measurement error into account, was obtained through a multidimensional Rasch modeling of the two constructs where the latent variance-covariance structure is directly estimated from the data. The results indicate that the participants tend to show overconfidence bias in their own cognitive abilities.

  11. Precision and Accuracy of Topography Measurements on Europa

    Science.gov (United States)

    Greenberg, R.; Hurford, T. A.; Foley, M. A.; Varland, K.

    2007-03-01

    Reports of the death of the melt-through model for chaotic terrain on Europa have been greatly exaggerated, to paraphrase Mark Twain. They are based on topographic maps of insufficient quantitative accuracy and precision.

  12. Effective Analysis of Chinese Word-Segmentation Accuracy

    Institute of Scientific and Technical Information of China (English)

    MA Weiyin

    2007-01-01

    Automatic word-segmentation is widely used in the ambiguity cancellation when processing large-scale real text,but during the process of unknown word detection in Chinese word segmentation,many detected word candidates are invalid.These false unknown word candidates deteriorate the overall segmentation accuracy,as it will affect the segmentation accuracy of known words.In this paper,we propose several methods for reducing the difficulties and improving the accuracy of the word-segmentation of written Chinese,such as full segmentation of a sentence,processing the duplicative word,idioms and statistical identification for unknown words.A simulation shows the feasibility of our proposed methods in improving the accuracy of word-segmentation of Chinese.

  13. Assessing and ensuring GOES-R magnetometer accuracy

    Science.gov (United States)

    Carter, Delano; Todirita, Monica; Kronenwetter, Jeffrey; Dahya, Melissa; Chu, Donald

    2016-05-01

    The GOES-R magnetometer subsystem accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma error per axis. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma error per axis. Error comes both from outside the magnetometers, e.g. spacecraft fields and misalignments, as well as inside, e.g. zero offset and scale factor errors. Because zero offset and scale factor drift over time, it will be necessary to perform annual calibration maneuvers. To predict performance before launch, we have used Monte Carlo simulations and covariance analysis. With the proposed calibration regimen, both suggest that the magnetometer subsystem will meet its accuracy requirements.

  14. Accuracy Assessment Points for Colorado National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This point file displays the 500 accuracy assessment (AA) points visited in July and August of 2004 as part of the vegetation mapping project. Five hundred and one...

  15. Accuracy Assessment Points for Wupatki National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This spatial dataset in ESRI Coverage format maps accuracy assessment point locations for the vegetation map at Wupatki National Monument and in the surrounding...

  16. A Novel Navigation Robustness and Accuracy Improvement System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for L1 C/A-based navigation with better anti-spoofing ability and higher accuracy, Broadata Communications, Inc. (BCI) proposes to develop a...

  17. Parenting and adolescents' accuracy in perceiving parental values.

    Science.gov (United States)

    Knafo, Ariel; Schwartz, Shalom H

    2003-01-01

    What determines adolescents' accuracy in perceiving parental values? The current study examined potential predictors including parental value communication, family value agreement, and parenting styles. In the study, 547 Israeli adolescents (aged 16 to 18) of diverse socioeconomic backgrounds participated with their parents. Adolescents reported the values they perceive their parents want them to hold. Parents reported their socialization values. Accuracy in perceiving parents' overall value system correlated positively with parents' actual and perceived value agreement and perceived parental warmth and responsiveness, but negatively with perceived value conflict, indifferent parenting, and autocratic parenting in all gender compositions of parent-child dyads. Other associations varied by dyad type. Findings were similar for predicting accuracy in perceiving two specific values: tradition and hedonism. The article discusses implications for the processes that underlie accurate perception, gender differences, and other potential influences on accuracy in value perception.

  18. Improvement of Electrochemical Machining Accuracy by Using Dual Pole Tool

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Electrochemical machining (ECM) is one of the best al ternatives for producing complex shapes in advanced materials used in aircraft a nd aerospace industries. However, the reduction of the stray material removal co ntinues to be major challenges for industries in addressing accuracy improvement . This study presents a method of improving machining accuracy in ECM by using a dual pole tool with a metallic bush outside the insulated coating of a cathode tool. The bush is connected with anode and so the el...

  19. The correlation between accent perception accuracy and listening proficiency

    Institute of Scientific and Technical Information of China (English)

    田方

    2012-01-01

    This study tries to examine the correlation between Chinese EFL learners' accent perception accuracy of and their lis- tening proficiency. Accent annotation data were collected from 80 English-majored freshmen and sophomores. Results show that their accent perception accuracy is positively related to their listening proficiency. Therefore, it is concluded that the teaching of the accent should be enhanced to help students overcome some supersegmental obstacles in their listening.

  20. Collective animal decisions: preference conflict and decision accuracy

    OpenAIRE

    Conradt, Larissa

    2013-01-01

    Social animals frequently share decisions that involve uncertainty and conflict. It has been suggested that conflict can enhance decision accuracy. In order to judge the practical relevance of such a suggestion, it is necessary to explore how general such findings are. Using a model, I examine whether conflicts between animals in a group with respect to preferences for avoiding false positives versus avoiding false negatives could, in principle, enhance the accuracy of collective decisions. I...

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

    Science.gov (United States)

    Aoki, Kazuhiro; Furusawa, Mitsuru

    2003-09-01

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

  2. Accuracy of ultrasound to identify chronic liver disease

    Institute of Scientific and Technical Information of China (English)

    Richard; Allan; Kerry; Thoirs; Maureen; Phillips

    2010-01-01

    AIM:To identify and assess studies reporting the diagnostic performance of ultrasound imaging for identifying chronic liver disease(CLD)in a high risk population. METHODS:A search was performed to identify studies investigating the diagnostic accuracy of ultrasound imaging for CLD.Two authors independently used the quality assessment of diagnostic accuracy studies(QUADAS)checklist to assess the methodological quality of the selected studies.Inter-observer reliability of the QUADAS tool was assessed by measu...

  3. Accuracy of Star Cluster Parameters from Integrated UBVRI Photometry

    CERN Document Server

    Narbutis, D; Stonkute, R; Vansevicius, V

    2007-01-01

    We study the capability of the UBVRI photometric system to quantify star clusters in terms of age, metallicity, and color excess by their integrated photometry. The well known age-metallicity-extinction degeneracy was analyzed for various parameter combinations, assuming different levels of photometric accuracy. We conclude that the UBVRI photometric system enables us to estimate star cluster parameters over a wide range, if the overall photometric accuracy is better than ~0.03 mag.

  4. Diagnostic Accuracy of the Initial Endoscopy for Ampullary Tumors

    OpenAIRE

    Lee, Hee Seung; Jang, Jong Soon; Lee, Seungho; Yeon, Myeong Ho; Kim, Ki Bae; Park, Jae Geun; Lee, Joo Young; Kim, Mi Jin; HAN, JOUNG-HO; Sung, Rohyun; Park, Seon Mee

    2015-01-01

    Background/Aims Ampullary tumors come in a wide variety of malignant forms. We evaluated the diagnostic accuracy of endoscopy for ampullary tumors, and analyzed the causes of misdiagnosis. Methods We compared endoscopic imaging and biopsy results to final diagnoses. Types of endoscope, numbers of biopsy specimens taken, and final diagnoses were evaluated as possible factors influencing diagnostic accuracy. Results Final diagnoses were 19 adenocarcinomas, 18 normal or papillitis, 11 adenomas, ...

  5. 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.

  6. Throwing speed and accuracy in baseball and cricket players.

    Science.gov (United States)

    Freeston, Jonathan; Rooney, Kieron

    2014-06-01

    Throwing speed and accuracy are both critical to sports performance but cannot be optimized simultaneously. This speed-accuracy trade-off (SATO) is evident across a number of throwing groups but remains poorly understood. The goal was to describe the SATO in baseball and cricket players and determine the speed that optimizes accuracy. 20 grade-level baseball and cricket players performed 10 throws at 80% and 100% of maximal throwing speed (MTS) toward a cricket stump. Baseball players then performed a further 10 throws at 70%, 80%, 90%, and 100% of MTS toward a circular target. Baseball players threw faster with greater accuracy than cricket players at both speeds. Both groups demonstrated a significant SATO as vertical error increased with increases in speed; the trade-off was worse for cricketers than baseball players. Accuracy was optimized at 70% of MTS for baseballers. Throwing athletes should decrease speed when accuracy is critical. Cricket players could adopt baseball-training practices to improve throwing performance.

  7. 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.

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

    Science.gov (United States)

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

    2016-11-01

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

  9. 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.

  10. Accuracy analysis and design of A3 parallel spindle head

    Science.gov (United States)

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

    2016-03-01

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

  11. Accuracy Analysis and Design of A3 Parallel Spindle Head

    Institute of Scientific and Technical Information of China (English)

    NI Yanbing; ZHANG Biao; SUN Yupeng; ZHANG Yuan

    2016-01-01

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

  12. Accuracy of the Soil Sealing Enhancement Product for Poland

    Directory of Open Access Journals (Sweden)

    Krówczyńska Małgorzata

    2016-09-01

    Full Text Available Increasing urbanization results in constant enlarging of the artificial area closed to water infiltration. In 2006–2008, the Soil Sealing Enhancement (SSE database was the part of the GMES Fast Track Service on Land Monitoring. The accuracy of the final product set by the authors should reach at least 85%. Orthorectified high resolution aerial photos of Poland were used to develop reference data constituting 20,000 random samples around the country. In each sample, the points were classified into three possible surface classes: natural, artificial and semi-sealed. Comparison of reference data to original project statistics revealed the values of accuracy, commission and omission errors in the SSE dataset. Although, SSE accuracy in Poland fulfils the criteria set by SSE authors with overall accuracy of 99.5%, the individual analysis for each category reveals many weaknesses. Preliminary interpretation of mistakes leads to the conclusion that the spatial resolution of pictures used in the SSE project is insufficient. In several cases, validation proved that omission errors were made in relation to construction sites or recently constructed buildings. It should be stated that the accuracy of SSE product for Poland should be treated as the maximum value of impervious surfaces.

  13. 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.

  14. Investigation of the Accuracy of Google Earth Elevation Data

    Science.gov (United States)

    El-Ashmawy, Khalid L. A.

    2016-09-01

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

  15. 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

  16. 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.

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

    Science.gov (United States)

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

    2010-10-01

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

  18. 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.

  19. Increased accuracy of ligand sensing by receptor internalization

    CERN Document Server

    Aquino, Gerardo

    2010-01-01

    Many types of cells can sense external ligand concentrations with cell-surface receptors at extremely high accuracy. Interestingly, ligand-bound receptors are often internalized, a process also known as receptor-mediated endocytosis. While internalization is involved in a vast number of important functions for the life of a cell, it was recently also suggested to increase the accuracy of sensing ligand as the overcounting of the same ligand molecules is reduced. Here we show, by extending simple ligand-receptor models to out-of-equilibrium thermodynamics, that internalization increases the accuracy with which cells can measure ligand concentrations in the external environment. Comparison with experimental rates of real receptors demonstrates that our model has indeed biological significance.

  20. Accuracy Analysis and Calibration of Gantry Hybrid Machine Tool

    Institute of Scientific and Technical Information of China (English)

    唐晓强; 李铁民; 尹文生; 汪劲松

    2003-01-01

    The kinematic accuracy is a key factor in the design of parallel or hybrid machine tools. This analysis improved the accuracy of a 4-DOF (degree of freedom) gantry hybrid machine tool based on a 3-DOF planar parallel manipulator by compensating for various positioning errors. The machine tool architecture was described with the inverse kinematic solution. The control parameter error model was used to analyze the accuracy of the 3-DOF planar parallel manipulator and to develop a kinematic calibration method. The experimental results prove that the calibration method reduces the cutter nose errors from ±0.50 mm to ±0.03 mm for a horizontal movement of 600 mm by compensating for errors in the slider home position, the guide way distance and the extensible strut home position. The calibration method will be useful for similar types of parallel kinematic machines.

  1. [Dimensional accuracy of microwave-cured denture base resin].

    Science.gov (United States)

    Uchida, K; Okamoto, F; Ogata, K; Sato, T

    1989-02-01

    Recently, microwave-cured denture base resin was developed, and the resin solved the problem of internal porosity which had been generated by curing the conventional denture base resins with microwave irradiation. In this study, the dimensional accuracy of microwave-cured denture base resin was compared with that of other denture base resins, such as pour-type resin, heat-cured resin and heat-shock resin. From the experiment, the following results were obtained. 1. Dimensional accuracy of microwave-cured denture base resin was better than that of heat-cured resin and heat-shock resin, and was similar to that of pour-type resin. 2. Dimensional accuracy of microwave-cured denture base resin by slow cooling method and rapid cooling method was almost the same. Those findings suggest that microwave-cured denture base resin is valuable in clinic.

  2. Quality--a radiology imperative: interpretation accuracy and pertinence.

    Science.gov (United States)

    Lee, Joseph K T

    2007-03-01

    Physicians as a group have neither consistently defined nor systematically measured the quality of medical practice. To referring clinicians and patients, a good radiologist is one who is accessible, recommends appropriate imaging studies, and provides timely consultation and reports with high interpretation accuracy. For determining the interpretation accuracy of cases with pathologic or surgical proof, the author proposes tracking data on positive predictive value, disease detection rates, and abnormal interpretation rates for individual radiologists. For imaging studies with no pathologic proof or adequate clinical follow-up, the author proposes measuring the concordance and discordance of the interpretations within a peer group. The monitoring of interpretation accuracy can be achieved through periodic imaging, pathologic correlation, regular peer review of randomly selected cases, or subscription to the ACR's RADPEER system. Challenges facing the implementation of an effective peer-review system include physician time, subjectivity in assessing discordant interpretations, lengthy and equivocal interpretations, and the potential misassignment of false-positive interpretations.

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

    DEFF Research Database (Denmark)

    Lyng, Nina

    Background This thesis is embedded in the emerging scientific discipline of public health nutrition and explores the methodological aspect of measuring children’s ability to report their school lunch consumption accurately. Children’s dietary intake does not concurwith nutritional recommendations...... or food-based dietary guidelines which constitutes a public health concern for several reasons. In Denmark children’s food consumption during school hours constitutes more than a third of children’s daily energy intake. Assessment of school lunch consumption among children in their natural settings holds...... among children has addressed accuracy in relation to school meals. However, in several countries including Denmark packed lunch is the prevalent lunch format and the lack of packed lunch reporting accuracy studies needs to be addressed to increase the knowledge about school hour reporting accuracy...

  4. Accuracy Improvement of Neutron Nuclear Data on Minor Actinides

    Directory of Open Access Journals (Sweden)

    Harada Hideo

    2015-01-01

    Full Text Available 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.

  5. Interpersonal orientation and the accuracy of personality judgments.

    Science.gov (United States)

    Vogt, Dawne S; Colvin, C Randall

    2003-04-01

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

  6. Accuracy of impressions obtained with dual-arch trays.

    Science.gov (United States)

    Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

    2009-01-01

    This study aimed to analyze the accuracy resulting from dual-arch impressions when compared to conventional impressions in complex preparations (ie, inlay and partial crown). One hundred eighty impressions were made using two different dual-arch trays; conventional trays served as the control. The accuracy of the dies obtained (Fuji-Rock EP, GC Europe) was assessed indirectly from the change of 59 transversal dimensions. Statistical analysis (t test, analysis of variance) revealed that less rigid dual-arch trays performed better than rigid ones. Though the inlay preparation was more difficult to reproduce with dual-arch trays, it can be concluded that the accuracy obtainable with nonrigid dual-arch trays is comparable to impressions taken from full-arch trays.

  7. High Accuracy Wavelength Calibration For A Scanning Visible Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Filippo Scotti and Ronald Bell

    2010-07-29

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies ≤ 0.2Â. An automated calibration for a scanning spectrometer has been developed to achieve a high wavelength accuracy overr the visible spectrum, stable over time and environmental conditions, without the need to recalibrate after each grating movement. The method fits all relevant spectrometer paraameters using multiple calibration spectra. With a steping-motor controlled sine-drive, accuracies of ~0.025 Â have been demonstrated. With the addition of high resolution (0.075 aresec) optical encoder on the grading stage, greater precision (~0.005 Â) is possible, allowing absolute velocity measurements with ~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.

  8. The changing uses of accuracy in science communication.

    Science.gov (United States)

    Hansen, Anders

    2016-10-01

    Tracing its historical trajectories, this article explores the preoccupation with accuracy in science communication research and explores the resurgence in the present century of concerns about accuracy, balance and impartiality in public communication of science. It is argued that many of the original insights from news and journalism research are still relevant and important if re-formulated in constructionist terms about voice, access and claims-making, and asking, in whose interest? Key to this is also the recognition of a radically changing - technologically, economically and professionally - media and communications environment, with implications for science journalism and a very different dynamic regarding the range and type of actors involved in discursively constructing opinions and information about controversial science and expertise. The article concludes with proposals for future emphases and directions in research broadly concerned with accuracy in science communication.

  9. Classification accuracy analyses using Shannon’s Entropy

    Directory of Open Access Journals (Sweden)

    Shashi Poonam Indwar

    2014-11-01

    Full Text Available There are many methods for determining the Classification Accuracy. In this paper significance of Entropy of training signatures in Classification has been shown. Entropy of training signatures of the raw digital image represents the heterogeneity of the brightness values of the pixels in different bands. This implies that an image comprising a homogeneous lu/lc category will be associated with nearly the same reflectance values that would result in the occurrence of a very low entropy value. On the other hand an image characterized by the occurrence of diverse lu/lc categories will consist of largely differing reflectance values due to which the entropy of such image would be relatively high. This concept leads to analyses of classification accuracy. Although Entropy has been used many times in RS and GIS but its use in determination of classification accuracy is new approach.

  10. 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.

  11. Effect of calibration method on Tekscan sensor accuracy.

    Science.gov (United States)

    Brimacombe, Jill M; Wilson, David R; Hodgson, Antony J; Ho, Karen C T; Anglin, Carolyn

    2009-03-01

    Tekscan pressure sensors are used in biomechanics research to measure joint contact loads. While the overall accuracy of these sensors has been reported previously, the effects of different calibration algorithms on sensor accuracy have not been compared. The objectives of this validation study were to determine the most appropriate calibration method supplied in the Tekscan program software and to compare its accuracy to the accuracy obtained with two user-defined calibration protocols. We evaluated the calibration accuracies for test loads within the low range, high range, and full range of the sensor. Our experimental setup used materials representing those found in standard prosthetic joints, i.e., metal against plastic. The Tekscan power calibration was the most accurate of the algorithms provided with the system software, with an overall rms error of 2.7% of the tested sensor range, whereas the linear calibrations resulted in an overall rms error of up to 24% of the tested range. The user-defined ten-point cubic calibration was almost five times more accurate, on average, than the power calibration over the full range, with an overall rms error of 0.6% of the tested range. The user-defined three-point quadratic calibration was almost twice as accurate as the Tekscan power calibration, but was sensitive to the calibration loads used. We recommend that investigators design their own calibration curves not only to improve accuracy but also to understand the range(s) of highest error and to choose the optimal points within the expected sensing range for calibration. Since output and sensor nonlinearity depend on the experimental protocol (sensor type, interface shape and materials, sensor range in use, loading method, etc.), sensor behavior should be investigated for each different application.

  12. Using checklists and algorithms to improve qualitative exposure judgment accuracy.

    Science.gov (United States)

    Arnold, Susan F; Stenzel, Mark; Drolet, Daniel; Ramachandran, Gurumurthy

    2016-01-01

    Most exposure assessments are conducted without the aid of robust personal exposure data and are based instead on qualitative inputs such as education and experience, training, documentation on the process chemicals, tasks and equipment, and other information. Qualitative assessments determine whether there is any follow-up, and influence the type that occurs, such as quantitative sampling, worker training, and implementing exposure and risk management measures. Accurate qualitative exposure judgments ensure appropriate follow-up that in turn ensures appropriate exposure management. Studies suggest that qualitative judgment accuracy is low. A qualitative exposure assessment Checklist tool was developed to guide the application of a set of heuristics to aid decision making. Practicing hygienists (n = 39) and novice industrial hygienists (n = 8) were recruited for a study evaluating the influence of the Checklist on exposure judgment accuracy. Participants generated 85 pre-training judgments and 195 Checklist-guided judgments. Pre-training judgment accuracy was low (33%) and not statistically significantly different from random chance. A tendency for IHs to underestimate the true exposure was observed. Exposure judgment accuracy improved significantly (p Qualitative judgments guided by the Checklist tool were categorically accurate or over-estimated the true exposure by one category 70% of the time. The overall magnitude of exposure judgment precision also improved following training. Fleiss' κ, evaluating inter-rater agreement between novice assessors was fair to moderate (κ = 0.39). Cohen's weighted and unweighted κ were good to excellent for novice (0.77 and 0.80) and practicing IHs (0.73 and 0.89), respectively. Checklist judgment accuracy was similar to quantitative exposure judgment accuracy observed in studies of similar design using personal exposure measurements, suggesting that the tool could be useful in developing informed priors and further

  13. 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.

  14. 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.

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

    Science.gov (United States)

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

    2003-05-01

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

  16. Vocal accuracy and neural plasticity following micromelody-discrimination training.

    Directory of Open Access Journals (Sweden)

    Jean Mary Zarate

    Full Text Available BACKGROUND: Recent behavioral studies report correlational evidence to suggest that non-musicians with good pitch discrimination sing more accurately than those with poorer auditory skills. However, other studies have reported a dissociation between perceptual and vocal production skills. In order to elucidate the relationship between auditory discrimination skills and vocal accuracy, we administered an auditory-discrimination training paradigm to a group of non-musicians to determine whether training-enhanced auditory discrimination would specifically result in improved vocal accuracy. METHODOLOGY/PRINCIPAL FINDINGS: We utilized micromelodies (i.e., melodies with seven different interval scales, each smaller than a semitone as the main stimuli for auditory discrimination training and testing, and we used single-note and melodic singing tasks to assess vocal accuracy in two groups of non-musicians (experimental and control. To determine if any training-induced improvements in vocal accuracy would be accompanied by related modulations in cortical activity during singing, the experimental group of non-musicians also performed the singing tasks while undergoing functional magnetic resonance imaging (fMRI. Following training, the experimental group exhibited significant enhancements in micromelody discrimination compared to controls. However, we did not observe a correlated improvement in vocal accuracy during single-note or melodic singing, nor did we detect any training-induced changes in activity within brain regions associated with singing. CONCLUSIONS/SIGNIFICANCE: Given the observations from our auditory training regimen, we therefore conclude that perceptual discrimination training alone is not sufficient to improve vocal accuracy in non-musicians, supporting the suggested dissociation between auditory perception and vocal production.

  17. 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.

  18. 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.

  19. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    Science.gov (United States)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  20. Efficiency, Robustness, and Accuracy in Picky Chart Parsing

    CERN Document Server

    Magerman, D M; Magerman, David M.; Weir, Carl

    1994-01-01

    This paper describes Picky, a probabilistic agenda-based chart parsing algorithm which uses a technique called {\\em probabilistic prediction} to predict which grammar rules are likely to lead to an acceptable parse of the input. Using a suboptimal search method, Picky significantly reduces the number of edges produced by CKY-like chart parsing algorithms, while maintaining the robustness of pure bottom-up parsers and the accuracy of existing probabilistic parsers. Experiments using Picky demonstrate how probabilistic modelling can impact upon the efficiency, robustness and accuracy of a parser.

  1. OPERATIONAL ACCURACY IMPROVEMENT OF DIGITAL SERVO SYSTEM CONTAINING UNBALANCED LOAD

    Directory of Open Access Journals (Sweden)

    A. Stryzhniou

    2013-01-01

    Full Text Available The paper considers a structural flowchart of a typical digital servo system and its operational principle. A method for determination of the unbalanced load effect on the accuracy of the system operation is described in the paper. The paper proposes a method for compensation of the  unbalanced load influence on the system operation. The experimental verification of the unbalanced load effect on the operational accuracy of the servo system and compensation of these influences have been executed in the paper.

  2. 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.

  3. Can we estimate the accuracy of ADME-Tox predictions?

    Science.gov (United States)

    Tetko, Igor V; Bruneau, Pierre; Mewes, Hans-Werner; Rohrer, Douglas C; Poda, Gennadiy I

    2006-08-01

    There have recently been developments in the methods used to access the accuracy of the prediction and applicability domain of absorption, distribution, metabolism, excretion and toxicity models, and also in the methods used to predict the physicochemical properties of compounds in the early stages of drug development. The methods are classified into two main groups: those based on the analysis of similarity of molecules, and those based on the analysis of calculated properties. An analysis of octanol-water distribution coefficients is used to exemplify the consistency of estimated and calculated accuracy of the ALOGPS program (http://www.vcclab.org) to predict in-house and publicly available datasets.

  4. Measurements of dimensional accuracy using linear and scanning profile techniques.

    Science.gov (United States)

    Harrison, A; Huggett, R; Zissis, A

    1992-01-01

    Various measurement methods have been described for the determination of dimensional accuracy and stability of denture base materials. This investigation introduces a computerised coordinate measuring machine (CCMM) and compares it with two methods routinely used for assessment of the accuracy of fit of denture base materials. The results demonstrate that the three methods (digital calipers, optical comparator, and CCMM) are acceptable for linear measurement. The CCMM was also used in its scanning mode to define and to quantify the contour changes of the resin bases. The advantages of the CCMM become apparent when two-dimensional changes require assessment.

  5. Diagnostic accuracy of magnetic resonance imaging of lumbar disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Takashi; Nakamura, Takafumi; Kikuchi, Taro; Watanabe, Hiroyuki; Takagi, Katsumasa; Yoshizumi, Kazuhiro; Katahira, Kazuhiro [Kumamoto Univ. (Japan). School of Medicine

    2000-03-01

    We studied the accuracy of MRI in lumbar disc herniation, comparing the results with the operative findings in the assessment of the rupture of the posterior longitudinal ligament (PLL), and type of herniation. The MRI findings in 47 subjects who were operated on for lumbar disc herniation were retrospectively studied. The accuracy rate was 75.2% for the rupture of the PLL and 40.4% for the type of herniation respectively. It was hard to differentiate subligamentous extrusion from transligamentous extrusion on MRI. (author)

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

    Science.gov (United States)

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

    2008-08-01

    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 fitting, and epidemiological analyses, the latter including sensitivity, specificity and positive predictive value for hypoglycaemia. Finally, recommendations for much needed head-to-head studies are given. This paper is a revised and adapted version of How to assess and compare the accuracy of continuous glucose monitors?, Diabetes Technology and Therapeutics 2007, in press, published with permission of the editor.

  7. Multimodal Biometric Systems - Study to Improve Accuracy and Performance

    CERN Document Server

    Sasidhar, K; Ramakrishna, Kolikipogu; KailasaRao, K

    2010-01-01

    Biometrics is the science and technology of measuring and analyzing biological data of human body, extracting a feature set from the acquired data, and comparing this set against to the template set in the database. Experimental studies show that Unimodal biometric systems had many disadvantages regarding performance and accuracy. Multimodal biometric systems perform better than unimodal biometric systems and are popular even more complex also. We examine the accuracy and performance of multimodal biometric authentication systems using state of the art Commercial Off- The-Shelf (COTS) products. Here we discuss fingerprint and face biometric systems, decision and fusion techniques used in these systems. We also discuss their advantage over unimodal biometric systems.

  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. Using judgement to improve accuracy in decision-making.

    Science.gov (United States)

    Dowding, Dawn; Thompson, Carl

    Nursing judgements are complex, often involving the need to process a large number of information cues. Key issues include how accurate they are and how we can improve levels of accuracy. Traditional approaches to the study of nursing judgement, characterised by qualitative and descriptive research, have provided valuable insights into the nature of expert nursing practice and the complexity of practice. However, they have largely failed to provide the data needed to address judgement accuracy. Social judgement analysis approaches are one way of overcoming these limitations. This paper argues that as nurses take on more roles requiring accurate judgement, it is time to increase our knowledge of judgement and ways to improve it.

  10. Subpixel accuracy for extracting groove center based on corner detection

    Institute of Scientific and Technical Information of China (English)

    Liu Suyi; Wang Guorong; Shi Yonghua

    2006-01-01

    Subpixel accuracy for V-groove center in robot welding is researched and a software measure to increase the accuracy of seam tracking by laser is presented.LOG( Laplacian of Gaussian ) operator is adopted to detect image edge.Vgroove center is extracted by corner detection of extremum curvature.Subpixel position is obtained by Lagarange polynomial interpolation algorithm.Experiment results show that the method is brief and applied, and is sufficient for the real time of robot welding by laser sensors.

  11. Research on target accuracy for ground-based lidar

    Science.gov (United States)

    Zhu, Ling; Shi, Ruoming

    2009-05-01

    In ground based Lidar system, the targets are used in the process of registration, georeferencing for point cloud, and also can be used as check points. Generally, the accuracy of capturing the flat target center is influenced by scanning range and scanning angle. In this research, the experiments are designed to extract accuracy index of the target center with 0-90°scan angles and 100-195 meter scan ranges using a Leica HDS3000 laser scanner. The data of the experiments are listed in detail and the related results are analyzed.

  12. Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy.

    Science.gov (United States)

    Zhao, Yi-Jiao; Xiong, Yu-Xue; Wang, Yong

    2017-01-01

    In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial "line-laser" scanner (Faro), as the reference model and two test models were obtained, via a "stereophotography" (3dMD) and a "structured light" facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and "3D error" as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use.

  13. Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy

    Science.gov (United States)

    Zhao, Yi-jiao; Xiong, Yu-xue; Wang, Yong

    2017-01-01

    In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial “line-laser” scanner (Faro), as the reference model and two test models were obtained, via a “stereophotography” (3dMD) and a “structured light” facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and “3D error” as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use. PMID:28056044

  14. Determination of elemental composition of volatile organic compounds from Chinese rose oil by spectral accuracy and mass accuracy.

    Science.gov (United States)

    Zhou, Wei; Zhang, Yaheng; Xu, Hongliang; Gu, Ming

    2011-10-30

    Elemental composition determination of volatile organic compounds through high mass accuracy and isotope pattern matching could not be routinely achieved with a unit-mass resolution mass spectrometer until the recent development of the comprehensive instrument line-shape calibration technology. Through this unique technology, both m/z values and mass spectral peak shapes are calibrated simultaneously. Of fundamental importance is that calibrated mass spectra have symmetric and mathematically known peak shapes, which makes it possible to deconvolute overlapped monoisotopes and their (13)C-isotope peaks and achieve accurate mass measurements. The key experimental requirements for the measurements are to acquire true raw data in a profile or continuum mode with the acquisition threshold set to zero. A total of 13 ions from Chinese rose oil were analyzed with internal calibration. Most of the ions produced high mass accuracy of better than 5 mDa and high spectral accuracy of better than 99%. These results allow five tested ions to be identified with unique elemental compositions and the other eight ions to be determined as a top match from multiple candidates based on spectral accuracy. One of them, a coeluted component (Nerol) with m/z 154, could not be identified by conventional GC/MS (gas chromatography/mass spectrometry) and library search. Such effective determination for elemental compositions of the volatile organic compounds with a unit-mass resolution quadrupole system is obviously attributed to the significant improvement of mass accuracy. More importantly, high spectral accuracy available through the instrument line-shape calibration enables highly accurate isotope pattern recognition for unknown identification.

  15. Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy

    OpenAIRE

    Zhao, Yi-jiao; Xiong, Yu-xue; Wang, Yong

    2017-01-01

    In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial “line-laser” scanner (Faro), as the reference model and two test models were obtained, via a “stereophotography” (3dMD) and a “structured light” facial scanner (FaceScan) ...

  16. Empathic accuracy for happiness in the daily lives of older couples: Fluid cognitive performance predicts pattern accuracy among men.

    Science.gov (United States)

    Hülür, Gizem; Hoppmann, Christiane A; Rauers, Antje; Schade, Hannah; Ram, Nilam; Gerstorf, Denis

    2016-08-01

    Correctly identifying other's emotional states is a central cognitive component of empathy. We examined the role of fluid cognitive performance for empathic accuracy for happiness in the daily lives of 86 older couples (mean relationship length = 45 years; mean age = 75 years) on up to 42 occasions over 7 consecutive days. Men performing better on the Digit Symbol test were more accurate in identifying ups and downs of their partner's happiness. A similar association was not found for women. We discuss the potential role of fluid cognitive performance and other individual, partner, and situation characteristics for empathic accuracy. (PsycINFO Database Record

  17. An Integrated MEMS Gyroscope Array with Higher Accuracy Output.

    Science.gov (United States)

    Chang, Honglong; Xue, Liang; Qin, Wei; Yuan, Guangmin; Yuan, Weizheng

    2008-04-28

    In this paper, an integrated MEMS gyroscope array method composed of two levels of optimal filtering was designed to improve the accuracy of gyroscopes. In the firstlevel filtering, several identical gyroscopes were combined through Kalman filtering into a single effective device, whose performance could surpass that of any individual sensor. The key of the performance improving lies in the optimal estimation of the random noise sources such as rate random walk and angular random walk for compensating the measurement values. Especially, the cross correlation between the noises from different gyroscopes of the same type was used to establish the system noise covariance matrix and the measurement noise covariance matrix for Kalman filtering to improve the performance further. Secondly, an integrated Kalman filter with six states was designed to further improve the accuracy with the aid of external sensors such as magnetometers and accelerometers in attitude determination. Experiments showed that three gyroscopes with a bias drift of 35 degree per hour could be combined into a virtual gyroscope with a drift of 1.07 degree per hour through the first-level filter, and the bias drift was reduced to 0.53 degree per hour after the second-level filtering. It proved that the proposed integrated MEMS gyroscope array is capable of improving the accuracy of the MEMS gyroscopes, which provides the possibility of using these low cost MEMS sensors in high-accuracy application areas.

  18. An Integrated MEMS Gyroscope Array with Higher Accuracy Output

    Directory of Open Access Journals (Sweden)

    Weizheng Yuan

    2008-04-01

    Full Text Available In this paper, an integrated MEMS gyroscope array method composed of two levels of optimal filtering was designed to improve the accuracy of gyroscopes. In the firstlevel filtering, several identical gyroscopes were combined through Kalman filtering into a single effective device, whose performance could surpass that of any individual sensor. The key of the performance improving lies in the optimal estimation of the random noise sources such as rate random walk and angular random walk for compensating the measurement values. Especially, the cross correlation between the noises from different gyroscopes of the same type was used to establish the system noise covariance matrix and the measurement noise covariance matrix for Kalman filtering to improve the performance further. Secondly, an integrated Kalman filter with six states was designed to further improve the accuracy with the aid of external sensors such as magnetometers and accelerometers in attitude determination. Experiments showed that three gyroscopes with a bias drift of 35 degree per hour could be combined into a virtual gyroscope with a drift of 1.07 degree per hour through the first-level filter, and the bias drift was reduced to 0.53 degree per hour after the second-level filtering. It proved that the proposed integrated MEMS gyroscope array is capable of improving the accuracy of the MEMS gyroscopes, which provides the possibility of using these low cost MEMS sensors in high-accuracy application areas.

  19. Narrative Transcription Accuracy and Reliability in Two Languages

    Science.gov (United States)

    Heilmann, John; Miller, Jon F.; Iglesias, Aquiles; Fabiano-Smith, Leah; Nockerts, Ann; Andriacchi, Karen Digney

    2008-01-01

    A study was conducted to examine the issues of accuracy and reliability for transcription and analysis of oral narratives from Spanish-English bilingual children. Findings reveal that oral narrative data from ELL children can be accurately transcribed and the narrative measures are stable over time.

  20. Asymptotic accuracy of Bayesian estimation for a single latent variable.

    Science.gov (United States)

    Yamazaki, Keisuke

    2015-09-01

    In data science and machine learning, hierarchical parametric models, such as mixture models, are often used. They contain two kinds of variables: observable variables, which represent the parts of the data that can be directly measured, and latent variables, which represent the underlying processes that generate the data. Although there has been an increase in research on the estimation accuracy for observable variables, the theoretical analysis of estimating latent variables has not been thoroughly investigated. In a previous study, we determined the accuracy of a Bayes estimation for the joint probability of the latent variables in a dataset, and we proved that the Bayes method is asymptotically more accurate than the maximum-likelihood method. However, the accuracy of the Bayes estimation for a single latent variable remains unknown. In the present paper, we derive the asymptotic expansions of the error functions, which are defined by the Kullback-Leibler divergence, for two types of single-variable estimations when the statistical regularity is satisfied. Our results indicate that the accuracies of the Bayes and maximum-likelihood methods are asymptotically equivalent and clarify that the Bayes method is only advantageous for multivariable estimations.

  1. Impulsivity and Speed-Accuracy Strategies in Intelligence Test Performance.

    Science.gov (United States)

    Phillips, Louise H.; Rabbitt, Patrick M. A.

    1995-01-01

    Whether relations between intelligence test performance and information processing measures depend on individual differences in speed-accuracy preferences rather than capacity limitations and whether the impact of strategic variables changes with increasing age or extraversion was studied with 83 adults ages 50 to 79 years. Results are discussed…

  2. 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.

  3. Reliability and Accuracy of Brain Volume Measurement on MR Imaging

    DEFF Research Database (Denmark)

    Yamagchii, Kechiro; Lassen, Anders; Ring, Poul

    1998-01-01

    Yamaguchi, K., Lassen, A. And Ring, P. Reliability and Accuracy of Brain Volume Measurement on MR Imaging. Abstract at ESMRMB98 European Society for Magnetic Resonance in Medicine and Biology, Geneva, Sept 17-20, 1998 Danish Research Center for Magnetic Resonance, Hvidovre University Hospital...

  4. Effects of Word Class Differences on L2 Pronunciation Accuracy.

    Science.gov (United States)

    Yeni-Komshian, Grace H.; Robbins, Medina; Flege, James E.

    2001-01-01

    Examined effect of word class (nouns vs. verbs) on second language pronunciation accuracy of Korean-English adult bilinguals whose age of arrival in the United States ranged from 6 to 23 years. Transcriptions of their productions of English indicated they were more accurate in pronouncing verbs than nouns and were more accurate in detecting…

  5. Accuracy of the NDI Wave Speech Research System

    Science.gov (United States)

    Berry, Jeffrey J.

    2011-01-01

    Purpose: This work provides a quantitative assessment of the positional tracking accuracy of the NDI Wave Speech Research System. Method: Three experiments were completed: (a) static rigid-body tracking across different locations in the electromagnetic field volume, (b) dynamic rigid-body tracking across different locations within the…

  6. Evaluation on the accuracy of digital elevation models

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There is a growing interest in investigating the accuracy of digital elevation model (DEM). However people usually have an unbalanced view on DEM errors. They emphasize DEM sampling errors, but ignore the impact of DEM resolution and terrain roughness on the accuracy of terrain representation. This research puts forward the concept of DEM terrain representation error (Et) and then investigates the generation, factors, measurement and simulation of DEM terrain representation errors. A multi-resolution and multi-relief comparative approach is used as the major methodology in this research. The experiment reveals a quantitative relationship between the error and the variation of resolution and terrain roughness at a global level. Root mean square error (RMS Et) is regressed against surface profile curvature (V) and DEM resolution (R) at 10 resolution levels. It is found that the RMS Et may be expressed as RMS Et = (0.0061· V+ 0.0052) . R - 0.022·V +0.2415. This result may be very useful in forecasting DEM accuracy, as well as in determining the DEM resolution related to the accuracy requirement of particular application.

  7. Encoding Modality Can Affect Memory Accuracy via Retrieval Orientation

    Science.gov (United States)

    Pierce, Benton H.; Gallo, David A.

    2011-01-01

    Research indicates that false memory is lower following visual than auditory study, potentially because visual information is more distinctive. In the present study we tested the extent to which retrieval orientation can cause a modality effect on memory accuracy. Participants studied unrelated words in different modalities, followed by criterial…

  8. Accuracy of the Dinamap 1846 XT automated blood pressure monitor.

    Science.gov (United States)

    Beaubien, E R; Card, C M; Card, S E; Biem, H J; Wilson, T W

    2002-09-01

    Accurate blood pressure (BP) measurement is important for the detection and treatment of hypertension. Despite widespread use of automated devices, there is limited published evidence for their reliability and accuracy. To determine the reliability and accuracy of the Dinamap 1846XT (Critikon Corporation, Tampa, FL, USA), a commonly used non-invasive oscillometric BP monitor The Dinamap was evaluated against the mercury manometer in 70 randomly selected adult hospitalised medical patients. Each individual underwent three sets of standardised BP measurement by automated method and three sets by mercury manometer by two independent observers. Reliability of BP measurement was assessed by repeated measures analysis. Dinamap accuracy was evaluated according to the American Association of Medical Instrumentation (AAMI) and British Hypertension Society (BHS) guidelines. Most patients were either normotensive or had stage I hypertension. The Dinamap tended to overestimate lower diastolic BP, and displayed poor reliability (P mercury manometer and 84% of systolic and 80% of diastolic readings were within 10 mm hg (bhs grade c). systolic and diastolic accuracy were worse with pressures >160/90 mm Hg (grade D) although these measures were based on a smaller sample of subjects. In conclusion the Dinamap yields inaccurate estimates of both systolic and diastolic BP even under standardised, and thus optimal conditions. This inaccuracy is exaggerated at higher BP (>160/90 mm Hg), although the number of measurements at higher pressures was small. We recommend that this device not be used when accurate BP measurement is needed for therapeutic decision-making.

  9. Precision and Accuracy Parameters in Structured Light 3-D Scanning

    DEFF Research Database (Denmark)

    Eiríksson, Eyþór Rúnar; Wilm, Jakob; Pedersen, David Bue

    2016-01-01

    Structured light systems are popular in part because they can be constructed from off-the-shelf low cost components. In this paper we quantitatively show how common design parameters affect precision and accuracy in such systems, supplying a much needed guide for practitioners. Our quantitative m...

  10. Accuracy Enhancement of Inertial Sensors Utilizing High Resolution Spectral Analysis

    Directory of Open Access Journals (Sweden)

    Michael Korenberg

    2012-08-01

    Full Text Available In both military and civilian applications, the inertial navigation system (INS and the global positioning system (GPS are two complementary technologies that can be integrated to provide reliable positioning and navigation information for land vehicles. The accuracy enhancement of INS sensors and the integration of INS with GPS are the subjects of widespread research. Wavelet de-noising of INS sensors has had limited success in removing the long-term (low-frequency inertial sensor errors. The primary objective of this research is to develop a novel inertial sensor accuracy enhancement technique that can remove both short-term and long-term error components from inertial sensor measurements prior to INS mechanization and INS/GPS integration. A high resolution spectral analysis technique called the fast orthogonal search (FOS algorithm is used to accurately model the low frequency range of the spectrum, which includes the vehicle motion dynamics and inertial sensor errors. FOS models the spectral components with the most energy first and uses an adaptive threshold to stop adding frequency terms when fitting a term does not reduce the mean squared error more than fitting white noise. The proposed method was developed, tested and validated through road test experiments involving both low-end tactical grade and low cost MEMS-based inertial systems. The results demonstrate that in most cases the position accuracy during GPS outages using FOS de-noised data is superior to the position accuracy using wavelet de-noising.

  11. A convenient accuracy criterion for time domain FE-calculations

    DEFF Research Database (Denmark)

    Jensen, Morten Skaarup

    1997-01-01

    An accuracy criterion that is well suited to tome domain finite element (FE) calculations is presented. It is then used to develop a method for selecting time steps and element meshes that produce accurate results without significantly overburderning the computer. Use of this method is illustrate...

  12. Effects of eye color and sex on accuracy in archery.

    Science.gov (United States)

    Beer, J; Fleming, P; Knorr, W

    1989-04-01

    126 subjects were 47 children in Grade 7, 49 students in Grade 8, and 30 adults, who shot arrows at bull's-eye targets from varying distances. Analysis of variance of accuracy scores indicated that there was no difference for eye color, but boys scored more points than did girls.

  13. Accuracy assessment of global barotropic ocean tide models

    DEFF Research Database (Denmark)

    Stammer, D.; Ray, R. D.; Andersen, Ole Baltazar

    2014-01-01

    The accuracy of state-of-the-art global barotropic tide models is assessed using bottom pressure data, coastal tide gauges, satellite altimetry, various geodetic data on Antarctic ice shelves, and independent tracked satellite orbit perturbations. Tide models under review include empirical, purel...

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

    Directory of Open Access Journals (Sweden)

    Mahroo Vojdani

    2015-01-01

    Conclusion: Within the limitations of this study, in parallel conditions, the type of impression material cannot affect the accuracy of the implant impressions; however, in nonparallel conditions, polyvinyl siloxane is shown to be a better choice, followed by vinyl siloxanether and polyether respectively.

  15. Efficiency and accuracy of Monte Carlo (importance) sampling

    NARCIS (Netherlands)

    Waarts, P.H.

    2003-01-01

    Monte Carlo Analysis is often regarded as the most simple and accurate reliability method. Be-sides it is the most transparent method. The only problem is the accuracy in correlation with the efficiency. Monte Carlo gets less efficient or less accurate when very low probabilities are to be computed

  16. DIPSY, a low-cost GPS application with high accuracy

    NARCIS (Netherlands)

    Heijden, W.F.M. van der

    1999-01-01

    To improve the control of unmanned aircraft flying out of visual range, the controller needs to be provided with real-time information about the position and behaviour of the drone during the flight. The position of the drone has to be presented with a relative high accuracy to obtain accurate lligh

  17. DIPSY, a low-cost GPS application with high accuracy

    NARCIS (Netherlands)

    Heijden, W.F.M. van der

    1998-01-01

    To improve the control of unmanned aircraft flying out of visual range, the controller needs to be provided with realtime information about the position and behaviour of the drone during the flight. The position of the drone has to be presented with a relative high accuracy to obtain accurate flight

  18. Separating Speed from Accuracy in Beginning Reading Development

    Science.gov (United States)

    Juul, Holger; Poulsen, Mads; Elbro, Carsten

    2014-01-01

    Phoneme awareness, letter knowledge, and rapid automatized naming (RAN) are well-known kindergarten predictors of later word recognition skills, but it is not clear whether they predict developments in accuracy or speed, or both. The present longitudinal study of 172 Danish beginning readers found that speed of word recognition mainly developed…

  19. Method for Improving Indoor Positioning Accuracy Using Extended Kalman Filter

    Directory of Open Access Journals (Sweden)

    Seoung-Hyeon Lee

    2016-01-01

    Full Text Available Beacons using bluetooth low-energy (BLE technology have emerged as a new paradigm of indoor positioning service (IPS because of their advantages such as low power consumption, miniaturization, wide signal range, and low cost. However, the beacon performance is poor in terms of the indoor positioning accuracy because of noise, motion, and fading, all of which are characteristics of a bluetooth signal and depend on the installation location. Therefore, it is necessary to improve the accuracy of beacon-based indoor positioning technology by fusing it with existing indoor positioning technology, which uses Wi-Fi, ZigBee, and so forth. This study proposes a beacon-based indoor positioning method using an extended Kalman filter that recursively processes input data including noise. After defining the movement of a smartphone on a flat two-dimensional surface, it was assumed that the beacon signal is nonlinear. Then, the standard deviation and properties of the beacon signal were analyzed. According to the analysis results, an extended Kalman filter was designed and the accuracy of the smartphone’s indoor position was analyzed through simulations and tests. The proposed technique achieved good indoor positioning accuracy, with errors of 0.26 m and 0.28 m from the average x- and y-coordinates, respectively, based solely on the beacon signal.

  20. Teaching Phonological Accuracy and Communicative Fluency at Thai Secondary Schools

    Science.gov (United States)

    Likitrattanaporn, Wannakarn

    2014-01-01

    The purpose of this investigation was to determine the opinions of secondary level Thai teachers who teach English. Their perspectives were collected and compared concerning phonological accuracy practice, communicative fluency activities, authentic teaching techniques and determining appropriate ways to solve the problems of phonological teaching…

  1. Assessing accuracy of an electronic provincial medication repository

    Directory of Open Access Journals (Sweden)

    Price Morgan

    2012-05-01

    Full Text Available Abstract Background Jurisdictional drug information systems are being implemented in many regions around the world. British Columbia, Canada has had a provincial medication dispensing record, PharmaNet, system since 1995. Little is known about how accurately PharmaNet reflects actual medication usage. Methods This prospective, multi-centre study compared pharmacist collected Best Possible Medication Histories (BPMH to PharmaNet profiles to assess accuracy of the PharmaNet profiles for patients receiving a BPMH as part of clinical care. A review panel examined the anonymized BPMHs and discrepancies to estimate clinical significance of discrepancies. Results 16% of medication profiles were accurate, with 48% of the discrepant profiles considered potentially clinically significant by the clinical review panel. Cardiac medications tended to be more accurate (e.g. ramipril was accurate >90% of the time, while insulin, warfarin, salbutamol and pain relief medications were often inaccurate (80–85% of the time. 1215 sequential BPMHs were collected and reviewed for this study. Conclusions The PharmaNet medication repository has a low accuracy and should be used in conjunction with other sources for medication histories for clinical or research purposes. This finding is consistent with other, smaller medication repository accuracy studies in other jurisdictions. Our study highlights specific medications that tend to be lower in accuracy.

  2. Impact Factor for Exclusive Diffractive Dijet Production with NLO Accuracy

    CERN Document Server

    Boussarie, R; Szymanowski, L; Wallon, S

    2016-01-01

    Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results.

  3. Coverage Accuracy of Confidence Intervals in Nonparametric Regression

    Institute of Scientific and Technical Information of China (English)

    Song-xi Chen; Yong-song Qin

    2003-01-01

    Point-wise confidence intervals for a nonparametric regression function with random design points are considered. The confidence intervals are those based on the traditional normal approximation and the empirical likelihood. Their coverage accuracy is assessed by developing the Edgeworth expansions for the coverage probabilities. It is shown that the empirical likelihood confidence intervals are Bartlett correctable.

  4. Accuracy characterization and measurement point planning for workpiece localization

    Institute of Scientific and Technical Information of China (English)

    ZHU Limin; LUO Honggen; DING Han

    2004-01-01

    This paper addresses the problem of accuracy characterization and measurement point planning for 3-D workpiece localization in the presence of part surface errors and measurement errors. Two frame-invariant functions of the infinitesimal rigid body displacement are defined to quantify the localization accuracy required by manufacturing processes. Then, two kinds of frame-invariant indices are derived to characterize the sensitivities of the accuracy measures to the sampling errors at the measurement points. With a dense set of discrete points on the workpiece datum surfaces pre-defined as candidates for measurement, planning of probing points for accurate recovery of part location is modeled as a combinatorial problem focusing on minimizing the accuracy sensitivity index. Based on an interchange rule, a greedy algorithm is developed to efficiently find a near-optimal solution. It is also shown that if the number of the measurement points is sufficiently large, there is no need to optimize their positions. Example confirms the validity of the presented indices and algorithm.

  5. An Information Theory Account of Preference Prediction Accuracy

    NARCIS (Netherlands)

    Pollmann, Monique; Scheibehenne, Benjamin

    2015-01-01

    Knowledge about other people's preferences is essential for successful social interactions, but what exactly are the driving factors that determine how well we can predict the likes and dislikes of people around us? To investigate the accuracy of couples’ preference predictions we outline and empiri

  6. Individual Differences in Absolute and Relative Metacomprehension Accuracy

    Science.gov (United States)

    Maki, Ruth H.; Shields, Micheal; Wheeler, Amanda Easton; Zacchilli, Tammy Lowery

    2005-01-01

    The authors investigated absolute and relative metacomprehension accuracy as a function of verbal ability in college students. Students read hard texts, revised texts, or a mixed set of texts. They then predicted their performance, took a multiple-choice test on the texts, and made posttest judgments about their performance. With hard texts,…

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

    Science.gov (United States)

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

    2010-01-01

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

  8. The rereading effect: metacomprehension accuracy improves across reading trials.

    Science.gov (United States)

    Rawson, K A; Dunlosky, J; Thiede, K W

    2000-09-01

    Guided by a hypothesis that integrates principles of monitoring from a cue-based framework of metacognitive judgments with assumptions about levels of text representation derived from theories of comprehension, we discovered that rereading improves metacomprehension accuracy. In Experiments 1 and 2, the participants read texts either once or twice, rated their comprehension for each text, and then were tested on the material. In both experiments, correlations between comprehension ratings and test scores were reliably greater for participants who reread texts than for participants who read texts only once. Furthermore, in contrast to the low levels of accuracy typically reported in the literature, rereading produced relatively high levels of accuracy, with the median gamma between ratings and test performance being +.60 across participants from both experiments. Our discussion focuses on two alternative hypotheses--that improved accuracy is an artifact of when judgments are collected or that it results from increased reliability of test performance--and on evidence that is inconsistent with these explanations for the rereading effect.

  9. Explanation Generation, Not Explanation Expectancy, Improves Metacomprehension Accuracy

    Science.gov (United States)

    Fukaya, Tatsushi

    2013-01-01

    The ability to monitor the status of one's own understanding is important to accomplish academic tasks proficiently. Previous studies have shown that comprehension monitoring (metacomprehension accuracy) is generally poor, but improves when readers engage in activities that access valid cues reflecting their situation model (activities such as…

  10. Accuracy of genomic selection using different methods to define haplotypes

    NARCIS (Netherlands)

    Calus, M.P.L.; Meuwissen, T.H.E.; Roos, de S.; Veerkamp, R.F.

    2008-01-01

    Genomic selection uses total breeding values for juvenile animals, predicted from a large number of estimated marker haplotype effects across the whole genome. In this study the accuracy of predicting breeding values is compared for four different models including a large number of markers, at diffe

  11. Accuracy of tunnelated vs. bolt-connected external ventricular drains

    DEFF Research Database (Denmark)

    Bergdal, Ove; Springborg, Jacob Bertram; Holst, Anders Vedel;

    2013-01-01

    Ventriculostomy is one of the most common neurosurgical procedures and an important tool in the treatment and monitoring of elevated intracranial pressure. Low accuracy has frequently been reported in the literature with risk of drain misplacement over 20% and with a need for reinsertion in up to...

  12. Ex-post evaluations of demand forecast accuracy

    DEFF Research Database (Denmark)

    Nicolaisen, Morten Skou; Driscoll, Patrick Arthur

    2014-01-01

    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...

  13. Solving the stability-accuracy-diversity dilemma of recommender systems

    Science.gov (United States)

    Hou, Lei; Liu, Kecheng; Liu, Jianguo; Zhang, Runtong

    2017-02-01

    Recommender systems are of great significance in predicting the potential interesting items based on the target user's historical selections. However, the recommendation list for a specific user has been found changing vastly when the system changes, due to the unstable quantification of item similarities, which is defined as the recommendation stability problem. To improve the similarity stability and recommendation stability is crucial for the user experience enhancement and the better understanding of user interests. While the stability as well as accuracy of recommendation could be guaranteed by recommending only popular items, studies have been addressing the necessity of diversity which requires the system to recommend unpopular items. By ranking the similarities in terms of stability and considering only the most stable ones, we present a top- n-stability method based on the Heat Conduction algorithm (denoted as TNS-HC henceforth) for solving the stability-accuracy-diversity dilemma. Experiments on four benchmark data sets indicate that the TNS-HC algorithm could significantly improve the recommendation stability and accuracy simultaneously and still retain the high-diversity nature of the Heat Conduction algorithm. Furthermore, we compare the performance of the TNS-HC algorithm with a number of benchmark recommendation algorithms. The result suggests that the TNS-HC algorithm is more efficient in solving the stability-accuracy-diversity triple dilemma of recommender systems.

  14. SUPERFUND GROUND WATER ISSUE - ACCURACY OF DEPTH TO WATER MEASUREMENTS

    Science.gov (United States)

    Accuracy of depth to water measurements is an issue identified by the Forum as a concern of Superfund decision-makers as they attempt to determine directions of ground-water flow, areas of recharge of discharge, the hydraulic characteristics of aquifers, or the effects of manmade...

  15. Accuracy Trumps Accent in Children's Endorsement of Object Labels

    Science.gov (United States)

    Corriveau, Kathleen H.; Kinzler, Katherine D.; Harris, Paul L.

    2013-01-01

    Past research provides evidence that children use at least 2 potentially competing strategies when choosing informants: they attend to informants' past accuracy and to their social identity (e.g., their status as native- vs. foreign-accented speakers). We explore how children reconcile these 2 strategies when they are put in conflict and whether…

  16. Improving Accuracy of Sleep Self-Reports through Correspondence Training

    Science.gov (United States)

    St. Peter, Claire C.; Montgomery-Downs, Hawley E.; Massullo, Joel P.

    2012-01-01

    Sleep insufficiency is a major public health concern, yet the accuracy of self-reported sleep measures is often poor. Self-report may be useful when direct measurement of nonverbal behavior is impossible, infeasible, or undesirable, as it may be with sleep measurement. We used feedback and positive reinforcement within a small-n multiple-baseline…

  17. Diagnostic accuracy of temporomandibular disorder pain tests: a multicenter study

    NARCIS (Netherlands)

    Visscher, C.M.; Naeije, M.; de Laat, A.; Michelotti, A.; Nilner, M.; Craane, B.; Ekberg, E.; Farella, M.; Lobbezoo, F.

    2009-01-01

    AIMS: To estimate the diagnostic accuracy of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) clinical examination and of the dynamic/static tests for the recognition of TMD pain. Since the diagnosis of TMD pain is especially complicated in persistent orofacial pain patient

  18. The accuracy of intensity ratings of emotions from facial expressions

    Directory of Open Access Journals (Sweden)

    Kostić Aleksandra P.

    2003-01-01

    Full Text Available The results of a study on the accuracy of intensity ratings of emotion from facial expressions are reported. The so far research into the field has shown that spontaneous facial expressions of basic emotions are a reliable source of information about the category of emotion. The question is raised of whether this can be true for the intensity of emotion as well and whether the accuracy of intensity ratings is dependent on the observer’s sex and vocational orientation. A total of 228 observers of both sexes and of various vocational orientations rated the emotional intensity of presented facial expressions on a scale-range from 0 to 8. The results have supported the hypothesis that spontaneous facial expressions of basic emotions do provide sufficient information about emotional intensity. The hypothesis on the interdependence between the accuracy of intensity ratings of emotion and the observer’s sex and vocational orientation has not been confirmed. However, the accuracy of intensity rating has been proved to vary with the category of the emotion presented.

  19. 40 CFR 1502.24 - Methodology and scientific accuracy.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Methodology and scientific accuracy. 1502.24 Section 1502.24 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY ENVIRONMENTAL IMPACT..., including scientific integrity, of the discussions and analyses in environmental impact statements....

  20. Online correction of scanning probe microscopes with pixel accuracy

    DEFF Research Database (Denmark)

    Dirscherl, Kai

    2000-01-01

    In this project ''Online Control of Scanning Probe Microscopes with Pixel Accuracy'', the development of an algorithm is described that enhances the measurement uncertainty of software controlled SPM by one order of magnitude from 2% to 0.2 %. The SPM is globally used as a metrological instruments...

  1. Improving Accuracy for Image Fusion in Abdominal Ultrasonography

    Directory of Open Access Journals (Sweden)

    Caroline Ewertsen

    2012-08-01

    Full Text Available Image fusion involving real-time ultrasound (US is a technique where previously recorded computed tomography (CT or magnetic resonance images (MRI are reformatted in a projection to fit the real-time US images after an initial co-registration. The co-registration aligns the images by means of common planes or points. We evaluated the accuracy of the alignment when varying parameters as patient position, respiratory phase and distance from the co-registration points/planes. We performed a total of 80 co-registrations and obtained the highest accuracy when the respiratory phase for the co-registration procedure was the same as when the CT or MRI was obtained. Furthermore, choosing co-registration points/planes close to the area of interest also improved the accuracy. With all settings optimized a mean error of 3.2 mm was obtained. We conclude that image fusion involving real-time US is an accurate method for abdominal examinations and that the accuracy is influenced by various adjustable factors that should be kept in mind.

  2. Accuracy of transferring microparts in a multi stage former

    DEFF Research Database (Denmark)

    Mahshid, Rasoul; Hansen, Hans Nørgaard; Arentoft, Mogens

    2013-01-01

    Many fasteners used in electromechanical systems are micro metal parts which should be manufactured with high accuracy and reliability and in large quantities. Micro forming is promising to fulfill these demands. This research focuses on investigating a gripping unit in a multi stage former, as t...

  3. DVCS on the nucleon to the twist-3 accuracy

    CERN Document Server

    Kivel, N A

    2001-01-01

    The amplitude of the deeply virtual Compton scattering off nucleon is computed to the twist-3 accuracy in the Wandzura-Wilczek (WW) approximation. The result is presented in the form which can be easily used for analysis of DVCS observables.

  4. DNA template dependent accuracy variation of nucleotide selection in transcription.

    Science.gov (United States)

    Mellenius, Harriet; Ehrenberg, Måns

    2015-01-01

    It has been commonly assumed that the effect of erroneous transcription of DNA genes into messenger RNAs on peptide sequence errors are masked by much more frequent errors of mRNA translation to protein. We present a theoretical model of transcriptional accuracy. It uses experimentally estimated standard free energies of double-stranded DNA and RNA/DNA hybrids and predicts a DNA template dependent transcriptional accuracy variation spanning several orders of magnitude. The model also identifies high-error as well a high-accuracy transcription motifs. The source of the large accuracy span is the context dependent variation of the stacking free energy of pairs of correct and incorrect base pairs in the ever moving transcription bubble. Our model predictions have direct experimental support from recent single molecule based identifications of transcriptional errors in the C. elegans transcriptome. Our conclusions challenge the general view that amino acid substitution errors in proteins are mainly caused by translational errors. It suggests instead that transcriptional error hotspots are the dominating source of peptide sequence errors in some DNA template contexts, while mRNA translation is the major cause of protein errors in other contexts.

  5. DNA template dependent accuracy variation of nucleotide selection in transcription.

    Directory of Open Access Journals (Sweden)

    Harriet Mellenius

    Full Text Available It has been commonly assumed that the effect of erroneous transcription of DNA genes into messenger RNAs on peptide sequence errors are masked by much more frequent errors of mRNA translation to protein. We present a theoretical model of transcriptional accuracy. It uses experimentally estimated standard free energies of double-stranded DNA and RNA/DNA hybrids and predicts a DNA template dependent transcriptional accuracy variation spanning several orders of magnitude. The model also identifies high-error as well a high-accuracy transcription motifs. The source of the large accuracy span is the context dependent variation of the stacking free energy of pairs of correct and incorrect base pairs in the ever moving transcription bubble. Our model predictions have direct experimental support from recent single molecule based identifications of transcriptional errors in the C. elegans transcriptome. Our conclusions challenge the general view that amino acid substitution errors in proteins are mainly caused by translational errors. It suggests instead that transcriptional error hotspots are the dominating source of peptide sequence errors in some DNA template contexts, while mRNA translation is the major cause of protein errors in other contexts.

  6. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

    Directory of Open Access Journals (Sweden)

    Kenjiro Fujii

    2016-01-01

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

  7. Dosing Accuracy of Insulin Pens Versus Conventional Syringes and Vials

    NARCIS (Netherlands)

    Y.M. Luijf; J.H. Devries

    2010-01-01

    Pen injection devices have acquired a pivotal role in insulin delivery, surpassing the use of conventional insulin syringes in many parts of the world. In this review we sought to determine differences in dosing accuracy between insulin pens and conventional syringes and vials, also touching on pati

  8. Enhancement of diffusers BSDF accuracy: spectral features effect

    NARCIS (Netherlands)

    Brug, H. van; Courrèges-Lacoste, G.B.; Otter, G.C.J.; Schaarsberg, J.G.; Delwart, S.; Del Bello, U.

    2006-01-01

    This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibratio

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

    Science.gov (United States)

    Ostrowski, W.

    2016-10-01

    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. The archived results

  10. 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

  11. Photogrammetric Accuracy and Modeling of Rolling Shutter Cameras

    Science.gov (United States)

    Vautherin, Jonas; Rutishauser, Simon; Schneider-Zapp, Klaus; Choi, Hon Fai; Chovancova, Venera; Glass, Alexis; Strecha, Christoph

    2016-06-01

    Unmanned aerial vehicles (UAVs) are becoming increasingly popular in professional mapping for stockpile analysis, construction site monitoring, and many other applications. Due to their robustness and competitive pricing, consumer UAVs are used more and more for these applications, but they are usually equipped with rolling shutter cameras. This is a significant obstacle when it comes to extracting high accuracy measurements using available photogrammetry software packages. In this paper, we evaluate the impact of the rolling shutter cameras of typical consumer UAVs on the accuracy of a 3D reconstruction. Hereto, we use a beta-version of the Pix4Dmapper 2.1 software to compare traditional (non rolling shutter) camera models against a newly implemented rolling shutter model with respect to both the accuracy of geo-referenced validation points and to the quality of the motion estimation. Multiple datasets have been acquired using popular quadrocopters (DJI Phantom 2 Vision+, DJI Inspire 1 and 3DR Solo) following a grid flight plan. For comparison, we acquired a dataset using a professional mapping drone (senseFly eBee) equipped with a global shutter camera. The bundle block adjustment of each dataset shows a significant accuracy improvement on validation ground control points when applying the new rolling shutter camera model for flights at higher speed (8m=s). Competitive accuracies can be obtained by using the rolling shutter model, although global shutter cameras are still superior. Furthermore, we are able to show that the speed of the drone (and its direction) can be solely estimated from the rolling shutter effect of the camera.

  12. On combining reference data to improve imputation accuracy.

    Directory of Open Access Journals (Sweden)

    Jun Chen

    Full Text Available Genotype imputation is an important tool in human genetics studies, which uses reference sets with known genotypes and prior knowledge on linkage disequilibrium and recombination rates to infer un-typed alleles for human genetic variations at a low cost. The reference sets used by current imputation approaches are based on HapMap data, and/or based on recently available next-generation sequencing (NGS data such as data generated by the 1000 Genomes Project. However, with different coverage and call rates for different NGS data sets, how to integrate NGS data sets of different accuracy as well as previously available reference data as references in imputation is not an easy task and has not been systematically investigated. In this study, we performed a comprehensive assessment of three strategies on using NGS data and previously available reference data in genotype imputation for both simulated data and empirical data, in order to obtain guidelines for optimal reference set construction. Briefly, we considered three strategies: strategy 1 uses one NGS data as a reference; strategy 2 imputes samples by using multiple individual data sets of different accuracy as independent references and then combines the imputed samples with samples based on the high accuracy reference selected when overlapping occurs; and strategy 3 combines multiple available data sets as a single reference after imputing each other. We used three software (MACH, IMPUTE2 and BEAGLE for assessing the performances of these three strategies. Our results show that strategy 2 and strategy 3 have higher imputation accuracy than strategy 1. Particularly, strategy 2 is the best strategy across all the conditions that we have investigated, producing the best accuracy of imputation for rare variant. Our study is helpful in guiding application of imputation methods in next generation association analyses.

  13. USE OF CHEMICAL INVENTORY ACCURACY MEASUREMENTS AS LEADING INDICATORS

    Energy Technology Data Exchange (ETDEWEB)

    Kuntamukkula, M.

    2011-02-10

    Chemical safety and lifecycle management (CSLM) is a process that involves managing chemicals and chemical information from the moment someone begins to order a chemical and lasts through final disposition(1). Central to CSLM is tracking data associated with chemicals which, for the purposes of this paper, is termed the chemical inventory. Examples of data that could be tracked include chemical identity, location, quantity, date procured, container type, and physical state. The reason why so much data is tracked is that the chemical inventory supports many functions. These functions include emergency management, which depends upon the data to more effectively plan for, and respond to, chemical accidents; environmental management that uses inventory information to aid in the generation of various federally-mandated and other regulatory reports; and chemical management that uses the information to increase the efficiency and safety with which chemicals are stored and utilized. All of the benefits of having an inventory are predicated upon having an inventory that is reasonably accurate. Because of the importance of ensuring one's chemical inventory is accurate, many have become concerned about measuring inventory accuracy. But beyond providing a measure of confidence in information gleaned from the inventory, does the inventory accuracy measurement provide any additional function? The answer is 'Yes'. It provides valuable information that can be used as a leading indicator to gauge the health of a chemical management system. In this paper, we will discuss: what properties make leading indicators effective, how chemical inventories can be used as a leading indicator, how chemical inventory accuracy can be measured, what levels of accuracies should realistically be expected in a healthy system, and what a subpar inventory accuracy measurement portends.

  14. Accuracy of the TRUGENE HIV-1 Genotyping Kit

    Science.gov (United States)

    Grant, Robert M.; Kuritzkes, Daniel R.; Johnson, Victoria A.; Mellors, John W.; Sullivan, John L.; Swanstrom, Ronald; D'Aquila, Richard T.; Van Gorder, Mark; Holodniy, Mark; Lloyd, Jr., Robert M.; Reid, Caroline; Morgan, Gillian F.; Winslow, Dean L.

    2003-01-01

    Drug resistance and poor virological responses are associated with well-characterized mutations in the viral reading frames that encode the proteins that are targeted by currently available antiretroviral drugs. An integrated system was developed that includes target gene amplification, DNA sequencing chemistry (TRUGENE HIV-1 Genotyping Kit), and hardware and interpretative software (the OpenGene DNA Sequencing System) for detection of mutations in the human immunodeficiency virus type 1 (HIV-1) protease and reverse transcriptase sequences. The integrated system incorporates reverse transcription-PCR from extracted HIV-1 RNA, a coupled amplification and sequencing step (CLIP), polyacrylamide gel electrophoresis, semiautomated analysis of data, and generation of an interpretative report. To assess the accuracy and robustness of the assay system, 270 coded plasma specimens derived from nine patients were sent to six laboratories for blinded analysis. All specimens contained HIV-1 subtype B viruses. Results of 270 independent assays were compared to “gold standard” consensus sequences of the virus populations determined by sequence analysis of 16 to 20 clones of viral DNA amplicons derived from two independent PCRs using primers not used in the kit. The accuracy of the integrated system for nucleotide base identification was 98.7%, and the accuracy for codon identification at 54 sites associated with drug resistance was 97.6%. In a separate analysis of plasma spiked with infectious molecular clones, the assay reproducibly detected all 72 different drug resistance mutations that were evaluated. There were no significant differences in accuracy between laboratories, between technologists, between kit lots, or between days. This integrated assay system for the detection of HIV-1 drug resistance mutations has a high degree of accuracy and reproducibility in several laboratories. PMID:12682149

  15. Clinical pedicle screw accuracy and deviation from planning in robot-guided spine surgery: robot-guided pedicle screw accuracy

    NARCIS (Netherlands)

    Dijk, van Joris D.; Ende, Roy P.J.; Stramigioli, Stefano; Köchling, Matthias; Höss, Norbert

    2015-01-01

    STUDY DESIGN: A retrospective chart review was performed for 112 consecutive minimally invasive spinal surgery patients who underwent pedicular screw fixation in a community hospital setting. OBJECTIVE: To assess the clinical accuracy and deviation in screw positions in robot-assisted pedicle screw

  16. Explained Variation and Predictive Accuracy with an Extension to the Competing Risks Model

    DEFF Research Database (Denmark)

    Rosthøj, Susanne; Keiding, Niels

    2003-01-01

    Competing risks; efficiency; explained variation; misspecification; predictive accuracy; survival analysis......Competing risks; efficiency; explained variation; misspecification; predictive accuracy; survival analysis...

  17. Accuracy analysis of a new Whipple shield ballistic limit equations

    Institute of Scientific and Technical Information of China (English)

    郑建东; 龚自正; 童靖宇; 张森; 侯明强

    2012-01-01

    文章提出一种新的 Whipple 防护结构弹道极限方程,对之进行了准确率分析,并与 NASA 约翰逊空间中心最新的 Christiansen 方程进行了对比。结果显示:新方程对国内外大量试验数据的预测准确率达到了78%,而 Christiansen 方程的预测准确率为72%。对于国内200多次超高速碰撞试验数据,新方程预测准确率为78%,而 Christiansen 方程仅为61%。可见,文章所提出的新方程对国内外材料具有高准确率和普适性,能够满足工程需要。该方程有效克服了国外有关弹道极限方程预测准确率低及通用性不强等缺点,可为我国空间站的 M/OD 撞击风险评估和防护设计提供技术支持及保障%This paper presents an accuracy analysis for a new ballistic limit equation (BLE) developed by our group for Whipple shield. The results are compared with those based on the newest Christiansen BLE developed by NASA’s Johnson Space Center. It is shown that the accuracy of our new BLE reaches 78% in predicting a large number of domestic and foreign HVI tests, while with the NASA’s BLE the accuracy reaches only 72%. Especially for more than 200 domestic tests, the accuracies are 78%and 61%, respectively. Therefore, our new BLE enjoys high accuracy and universal applicability for domestic and foreign materials, and can meet the requirements in engineering applications. Our new BLE effectively improves the accuracy and overcomes the compatibility problem of the NASA’s BLE, and can provide a technical support for engineers in designing shields and conducting risk assessment for China’s future space stations.

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

    Science.gov (United States)

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

    2017-03-01

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

  19. The use of low density high accuracy (LDHA) data for correction of high density low accuracy (HDLA) point cloud

    Science.gov (United States)

    Rak, Michal Bartosz; Wozniak, Adam; Mayer, J. R. R.

    2016-06-01

    Coordinate measuring techniques rely on computer processing of coordinate values of points gathered from physical surfaces using contact or non-contact methods. Contact measurements are characterized by low density and high accuracy. On the other hand optical methods gather high density data of the whole object in a short time but with accuracy at least one order of magnitude lower than for contact measurements. Thus the drawback of contact methods is low density of data, while for non-contact methods it is low accuracy. In this paper a method for fusion of data from two measurements of fundamentally different nature: high density low accuracy (HDLA) and low density high accuracy (LDHA) is presented to overcome the limitations of both measuring methods. In the proposed method the concept of virtual markers is used to find a representation of pairs of corresponding characteristic points in both sets of data. In each pair the coordinates of the point from contact measurements is treated as a reference for the corresponding point from non-contact measurement. Transformation enabling displacement of characteristic points from optical measurement to their match from contact measurements is determined and applied to the whole point cloud. The efficiency of the proposed algorithm was evaluated by comparison with data from a coordinate measuring machine (CMM). Three surfaces were used for this evaluation: plane, turbine blade and engine cover. For the planar surface the achieved improvement was of around 200 μm. Similar results were obtained for the turbine blade but for the engine cover the improvement was smaller. For both freeform surfaces the improvement was higher for raw data than for data after creation of mesh of triangles.

  20. Accuracy of Travel Time Estimation using Bluetooth Technology

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Skoven Pedersen, Kristian; Tørholm Christensen, Lars

    2012-01-01

    Short-term travel time information plays a critical role in Advanced Traffic Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS). In this context, the need for accurate and reliable travel time information sources is becoming increasingly important. Bluetooth Technology (BT......) has been used as a relatively new cost-effective source of travel time estimation. However, due to low sampling rate of BT compared to other sensor technologies, existence of outliers may significantly affect the accuracy and reliability of the travel time estimates obtained using BT. In this study......, the concept of outliers and corresponding impacts on travel time accuracy are discussed. Four different estimators named Min-BT, Max-BT, Med-BT and Avg-BT with different outlier detection logic are presented in this paper. These methods are used to estimate travel times using a BT derived dataset. In order...

  1. Compensation of motion error in a high accuracy AFM

    Science.gov (United States)

    Cui, Yuguo; Arai, Yoshikazu; He, Gaofa; Asai, Takemi; Gao, Wei

    2008-10-01

    An atomic force microscope (AFM) system is used for large-area measurement with a spiral scanning strategy, which is composed of an air slide, an air spindle and a probe unit. The motion error which is brought from the air slide and the air spindle will increase with the increasing of the measurement area. Then the measurement accuracy will decrease. In order to achieve a high speed and high accuracy measurement, the probe scans along X-direction with constant height mode driven by the air slide, and at the same time, based on the change way of the motion error, it moves along Zdirection conducted by piezoactuator. According to the above method of error compensation, the profile measurement experiment of a micro-structured surface has been carried out. The experimental result shows that this method is effective for eliminating motion error, and it can achieve high speed and precision measurement of micro-structured surface.

  2. Accuracy improvement in digital holographic microtomography by multiple numerical reconstructions

    Science.gov (United States)

    Ma, Xichao; Xiao, Wen; Pan, Feng

    2016-11-01

    In this paper, we describe a method to improve the accuracy in digital holographic microtomography (DHMT) for measurement of thick samples. Two key factors impairing the accuracy, the deficiency of depth of focus and the rotational error, are considered and addressed simultaneously. The hologram is propagated to a series of distances by multiple numerical reconstructions so as to extend the depth of focus. The correction of the rotational error, implemented by numerical refocusing and image realigning, is merged into the computational process. The method is validated by tomographic results of a four-core optical fiber and a large mode optical crystal fiber. A sample as thick as 258 μm is accurately reconstructed and the quantitative three-dimensional distribution of refractive index is demonstrated.

  3. On the accuracy of solving confluent Prony systems

    CERN Document Server

    Batenkov, Dmitry

    2011-01-01

    In this paper we consider several nonlinear systems of algebraic equations which can be called "Prony-type". These systems arise in various reconstruction problems in several branches of theoretical and applied mathematics. Usually, the underlying models exhibit some kind of discontinuities, and the said systems happen to capture their discontinuous nature in geometric terms. Consequently, the question of stability of solution with respect to errors in the right-hand side becomes critical for the success of any particular application. We investigate the question of "maximal possible accuracy" of solving Prony-type systems, putting stress on the "local" behaviour which approximates situations with low absolute measurement error. The accuracy estimates are formulated in very simple geometric terms, shedding some light on the structure of the problem. A comparison with recurrence-based "global" solution method is also provided.

  4. Extrinsic factors affecting accuracy of ultrasonic flowmeters for LMFBRs

    Energy Technology Data Exchange (ETDEWEB)

    Managan, W.W.

    1976-08-01

    Assuming that ultrasonic flowmeters of suitable intrinsic accuracy are feasible, this report explores factors extrinsic to the flowmeter which affect the accuracy such as asymmetric flow profile, regions of high turbulence and thermal stratification. By integrating isovelocity flow profile maps, the predicted performance of various flowmeter configurations may be compared to experimental data. For the two pipe arrangements analyzed, the single diametral path flowmeter results were within 5 percent of true flow rate. Theoretical correction factors could reduce the error for the straight pipe but increased the error for asymmetrical flow. On the same pipe arrangements a four path ultrasonic flowmeter spaced for Gaussian integration gave less than 1 percent error. For more general conclusions a range of flow profiles produced by typical LMFBR piping arrangements must be analyzed.

  5. Accuracy Assessment of Digital Elevation Models Using GPS

    Science.gov (United States)

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

    2008-01-01

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

  6. Clinical assessment of intraarterial blood gas monitor accuracy

    Science.gov (United States)

    Aziz, Salim; Spiess, R.; Roby, Paul; Kenny, Margaret

    1993-08-01

    The accuracy of intraarterial blood gas monitoring (IABGM) devices is challenging to assess under routine clinical conditions. When comparing discrete measurements by blood gas analyzer (BGA) to IABGM values, it is important that the BGA determinations (reference method) be as accurate as possible. In vitro decay of gas tensions caused by delay in BGA analysis is particularly problematic for specimens with high arterial oxygen tension (PaO2) values. Clinical instability of blood gases in the acutely ill patient may cause disagreement between BGA and IABGM values because of IABGM response time lag, particularly in the measurement of arterial blood carbon dioxide tension (PaCO2). We recommend that clinical assessments of IABGM accuracy by comparison with BGA use multiple bedside BGA instruments, and that blood sampling only occur during periods when IABGM values appear stable.

  7. Evaluation of Small Unmanned Aircraft Flight Trajectory Accuracy

    Directory of Open Access Journals (Sweden)

    Ramūnas Kikutis

    2014-12-01

    Full Text Available Today small unmanned aircraft are being more widely adapted for practical tasks. These tasks require high reliability and flight path accuracy. For such aircraft we have to deal with the chalenge how to compensate external factors and how to ensure the accuracy of the flight trajectory according to new regulations and standards. In this paper, new regulations for the flights of small unmanned aircraft in Lithuanian air space are discussed. Main factors, which affect errors of the autonomous flight path tracking, are discussed too. The emphasis is on the wind factor and the flight path of Dubbin’s trajectories. Research was performed with mathematical-dynamic model of UAV and it was compared with theoretical calculations. All calculations and experiments were accomplished for the circular part of Dubbin’s paths when the airplane was trimmed for circular trajectory flight in calm conditions. Further, for such flight the wind influence was analysed.

  8. Evaluating the accuracy of the dynamic mode decomposition

    Science.gov (United States)

    Zhang, Hao; Dawson, Scott; Rowley, Clarence; Deem, Eric; Cattafesta, Louis

    2016-11-01

    Dynamic mode decomposition (DMD) is a practical way to extract dynamic information about a fluid flow directly from data. As a data-driven method, DMD can suffer from error, which can be difficult to quantify without knowledge of an exact solution, free from noise or external disturbances. Here we propose an evaluation metric for the accuracy of DMD results (eigenvalues, modes, and eigenfunctions), by exploiting a connection between DMD and the Koopman operator, a linear operator acting on functions of the flow state. In particular, a DMD mode is considered "accurate" if the corresponding eigenfunction closely approximates a Koopman eigenfunction. With this definition, we can assess the accuracy of any individual DMD mode directly from data, without requiring the direct calculation of the Koopman operator. We demonstrate the use of this criterion with a range of examples including synthetic, numerical, and experimental data. Supported by AFOSR Grant FA9550-14-1-0289.

  9. The effects of domain knowledge on metacomprehension accuracy.

    Science.gov (United States)

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

    2009-10-01

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

  10. Accuracy Analysis of Attitude Computation Based on Optimal Coning Algorithm

    Directory of Open Access Journals (Sweden)

    Jianfeng Chen

    2012-09-01

    Full Text Available To accurately evaluate the applicability of optimal coning algorithms, the direct influence of their periodic components on attitude accuracy is investigated. The true value of the change of the rotation vector is derived from the classical coning motion for analytic comparison. The analytic results show that the influence of periodic components is mostly dominant in two types of optimal coning algorithms. Considering that the errors of periodic components cannot be simply neglected, these algorithms are categorized with simplified forms. A variety of simulations are done under the classical coning motion. The numerical results are in good agreement with the analytic deductions. Considering their attitude accuracy, optimal coning algorithms of the 4-subinterval and 5-subinterval algorithms optimized with angular increments are not recommended for use for real application.

  11. Accuracy Analysis of Attitude Computation Based on Optimal Coning Algorithm

    Directory of Open Access Journals (Sweden)

    Xiyuan Chen

    2012-11-01

    Full Text Available To accurately evaluate the applicability of optimal coning algorithms, the direct influence of their periodic components on attitude accuracy is investigated. The true value of the change of the rotation vector is derived from the classical coning motion for analytic comparison. The analytic results show that the influence of periodic components is mostly dominant in two types of optimal coning algorithms. Considering that the errors of periodic components cannot be simply neglected, these algorithms are categorized with simplified forms. A variety of simulations are done under the classical coning motion. The numerical results are in good agreement with the analytic deductions. Considering their attitude accuracy, optimal coning algorithms of the 4-subinterval and 5-subinterval algorithms optimized with angular increments are not recommended for use for real application.Defence Science Journal, 2012, 62(6, pp.361-368, DOI:http://dx.doi.org/10.14429/dsj.62.1430

  12. Accuracy Improvement for Stiffness Modeling of Parallel Manipulators

    CERN Document Server

    Pashkevich, Anatoly; Chablat, Damien; Wenger, Philippe

    2009-01-01

    The paper focuses on the accuracy improvement of stiffness models for parallel manipulators, which are employed in high-speed precision machining. It is based on the integrated methodology that combines analytical and numerical techniques and deals with multidimensional lumped-parameter models of the links. The latter replace the link flexibility by localized 6-dof virtual springs describing both translational/rotational compliance and the coupling between them. There is presented detailed accuracy analysis of the stiffness identification procedures employed in the commercial CAD systems (including statistical analysis of round-off errors, evaluating the confidence intervals for stiffness matrices). The efficiency of the developed technique is confirmed by application examples, which deal with stiffness analysis of translational parallel manipulators.

  13. Extent, accuracy, and credibility of breastfeeding information on the Internet.

    Science.gov (United States)

    Shaikh, Ulfat; Scott, Barbara J

    2005-05-01

    Our objective was to test and describe a model for evaluating Websites related to breastfeeding. Forty Websites most likely to be accessed by the public were evaluated for extent, accuracy, credibility, presentation, ease of use, and adherence to ethical and medical Internet publishing standards. Extent and accuracy of Website content were determined by a checklist of critical information. The majority of Websites reviewed provided accurate information and complied with the International Code of Marketing of Breast-milk Substitutes. Approximately half the Websites complied with standards of medical Internet publishing. While much information on breastfeeding on the Internet is accurate, there is wide variability in the extent of information, usability of Websites, and compliance with standards of medical Internet publishing. Results of this study may be helpful to health care professionals as a model for evaluating breastfeeding-related Websites and to highlight considerations when recommending or designing Websites.

  14. Simultaneously improving the sensitivity and absolute accuracy of CPT magnetometer.

    Science.gov (United States)

    Liang, Shang-Qing; Yang, Guo-Qing; Xu, Yun-Fei; Lin, Qiang; Liu, Zhi-Heng; Chen, Zheng-Xiang

    2014-03-24

    A new method to improve the sensitivity and absolute accuracy simultaneously for coherent population trapping (CPT) magnetometer based on the differential detection method is presented. Two modulated optical beams with orthogonal circular polarizations are applied, in one of which two magnetic resonances are excited simultaneously by modulating a 3.4GHz microwave with Larmor frequency. When a microwave frequency shift is introduced, the difference in the power transmitted through the cell in each beam shows a low noise resonance. The sensitivity of 2pT/Hz @ 10Hz is achieved. Meanwhile, the absolute accuracy of ± 0.5nT within the magnetic field ranging from 20000nT to 100000nT is realized.

  15. Accuracy of whole-body plethysmography requires biological calibration

    DEFF Research Database (Denmark)

    Poorisrisak, Porntiva; Vrang, Carsten; Henriksen, Jorn Molgaard

    2009-01-01

    preschool children) were generated and were without significant difference between centers and independent of height, weight, age, and gender. We subsequently pooled these normative data (105 children) with our previous data from 121 healthy young children (overall mean sRaw, 1.27; SD, 0.25). CONCLUSION......: Control using biological standards revealed errors in the factory setting and highlights the need for developing methods for verification of resistance measures to assure accuracy. Normative data were subsequently generated. Importantly, other centers using such normative data should first consider proper...... of accuracy. Our aim was to determine the agreement of sRaw measurements in six centers and expand normative sRaw values for nonasthmatic children including these centers. METHOD: Identical hardware with different software versions was used at the six centers. Measurements followed a standard operating...

  16. Geolocation by light: accuracy and precision affected by environmental factors

    DEFF Research Database (Denmark)

    Lisovski, Simeon; Hewson, Chris M.; Klaassen, Raymond H.G.;

    2012-01-01

    investigated the influence of different calibration methods on the accuracy of the latitudinal positions. 4. All three environmental factors can influence the light intensity pattern significantly. Weather and an animal’s behaviour result in increased noise in positioning, whereas topography and vegetation...... result in systematic shading and biased positions. Calibration can significantly shift the estimated latitudes and potentially increase the accuracy, but detailed knowledge about the particular confounding factors and the behaviour of the studied animal is crucial for the choice of the most appropriate......1. Geolocation by light allows for tracking animal movements, based on measurements of light intensity over time by a data-logging device (‘geolocator’). Recent developments of ultra-light devices (

  17. Accuracy of Star Cluster Parameters from Integrated UBVRIJHK Photometry

    CERN Document Server

    Bridzius, A; Stonkute, R; Deveikis, V; Vansevicius, V

    2009-01-01

    We investigate the capability of the UBVRIJHK photometric system to quantify star clusters in terms of age, metallicity and color excess by their integrated photometry in the framework of PEGASE single stellar population (SSP) models. The age-metallicity-extinction degeneracy was analyzed for various parameter combinations, assuming different levels of photometric accuracy. We conclude, that most of the parameter degeneracies, typical to the UBVRI photometric system, are broken in the case when the photometry data are supplemented with at least one infrared magnitude of the JHK passbands, with an accuracy better than ~0.05 mag. The presented analysis with no preassumptions on the distribution of photometric errors of star cluster models, provides estimate of the intrinsic capability of any photometric system to determine star cluster parameters from integrated photometry.

  18. Location Update Accuracy in Human Tracking system using Zigbee modules

    CERN Document Server

    Amutha, B

    2009-01-01

    A location and tracking system becomes very important to our future world of pervasive computing. An algorithm for accurate location information is being incorporated in the human walking model and in the blind human walking model. We want to implement an accurate location tracking mechanism using Zigbee along with GPS, we have incorporated Markov chain algorithm for establishing accuracy. Normal Human and blind human walking steps were actually taken in the known environment within our campus and the Markov chain algorithm was used for smoothening the stepwise variation in location updates. A comparison module is also implemented to show the difference between normal human and blind human walking step variations. This accuracy is used for designing a blind tracking device so that the device can be used by the blind for finding the path without obstacles. We present a system level approach to localizing and tracking Human and blind users on a basis of different sources of location information [GPS plus Zigbee...

  19. Accuracy of quantitative reconstructions in SPECT/CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbinin, S; Celler, A [Department of Radiology, University of British Columbia, 366-828 West 10th Avenue, Vancouver BC, V5Z 1L8 (Canada); Belhocine, T; Vanderwerf, R; Driedger, A [Department of Nuclear Medicine, London Health Sciences Centre, 375 South Street, PO Box 5375, London ON, N6A 4G5 (Canada)], E-mail: shcher2@interchange.ubc.ca

    2008-09-07

    The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed inside an anthropometric Thorax phantom filled with non-radioactive water. Corrections for attenuation, scatter, collimator blurring and collimator septal penetration were applied and their contribution to the overall accuracy of the reconstruction was evaluated. Reconstruction with the most comprehensive set of corrections resulted in activity estimation with error levels of 3-5% for all the isotopes.

  20. High Accuracy and Real-Time Gated Viewing Laser Radar

    Institute of Scientific and Technical Information of China (English)

    Dong Li; Hua-Jun Yang; Shan-Pei Zhou

    2011-01-01

    A gated viewing laser radar has an excellent performance in underwater low light level imaging,and it also provides a viable solution to inhibit backscattering.In this paper,a gated viewing imaging system according to the demand for real-time imaging is presented,and then the simulation is used to analyze the performance of the real-time gated viewing system.The range accuracy performance is limited by the slice number,the width of gate,the delay time step,the initial delay time,as well as the system noise and atmospheric turbulence.The simulation results indicate that the highest range accuracy can be achieved when the system works with the optimal parameters.Finally,how to choose the optimal parameters has been researched.

  1. When anticipation beats accuracy: Threat alters memory for dynamic scenes.

    Science.gov (United States)

    Greenstein, Michael; Franklin, Nancy; Martins, Mariana; Sewack, Christine; Meier, Markus A

    2016-05-01

    Threat frequently leads to the prioritization of survival-relevant processes. Much of the work examining threat-related processing advantages has focused on the detection of static threats or long-term memory for details. In the present study, we examined immediate memory for dynamic threatening situations. We presented participants with visually neutral, dynamic stimuli using a representational momentum (RM) paradigm, and manipulated threat conceptually. Although the participants in both the threatening and nonthreatening conditions produced classic RM effects, RM was stronger for scenarios involving threat (Exps. 1 and 2). Experiments 2 and 3 showed that this effect does not generalize to the nonthreatening objects within a threatening scene, and that it does not extend to arousing happy situations. Although the increased RM effect for threatening objects by definition reflects reduced accuracy, we argue that this reduced accuracy may be offset by a superior ability to predict, and thereby evade, a moving threat.

  2. Accuracy Validation for Medical Image Registration Algorithms: a Review

    Institute of Scientific and Technical Information of China (English)

    Zhe Liu; Xiang Deng; Guang-zhi Wang

    2012-01-01

    Accuracy validation is essential to clinical application of medical image registration techniques.Registration validation remains a challenging problem in practice mainly due to lack of 'ground truth'.In this paper,an overview of current validation methods for medical image registration is presented with detailed discussion of their benefits and drawbacks.Special focus is on non-rigid registration validation.Promising solution is also discussed.

  3. An evaluation of conflation accuracy using finite-state transducers

    OpenAIRE

    Galvez, Carmen; De-Moya-Anegón, Félix

    2006-01-01

    Purpose – To evaluate the accuracy of conflation methods based on Finite-State Transducers (FSTs). Design/methodology/approach – Incorrectly lemmatized and stemmed forms may lead to the retrieval of inappropriate documents. Experimental studies to date have focused on retrieval performance, but very few on conflation performance. The process of normalization we used involved a linguistic toolbox that allowed us to construct, through graphic interfaces, electronic dictionaries represented i...

  4. Use and Abuse of the Model Waveform Accuracy Standards

    Science.gov (United States)

    Lindblom, Lee

    2010-02-01

    Accuracy standards have been developed to ensure that the waveforms used for gravitational-wave data analysis are good enough to serve their intended purposes. These standards place constraints on certain norms of the frequency-domain representations of the waveform errors. Examples will be presented of possible misinterpretations and misapplications of these standards, whose effect could be to vitiate the quality control they were intended to enforce. Suggestions will be given for ways to avoid these problems. )

  5. ON THE ANISOTROPIC ACCURACY ANALYSIS OF ACM'S NONCONFORMING FINITE ELEMENT

    Institute of Scientific and Technical Information of China (English)

    Dong-yang Shi; Shi-peng Mao; Shao-chun Chen

    2005-01-01

    The main aim of this paper is to study the superconvergence accuracy analysis of the famous ACM's nonconforming finite element for biharmonic equation under anisotropic meshes. By using some novel approaches and techniques, the optimal anisotropic interpolation error and consistency error estimates are obtained. The global error is of order O(h2). Lastly, some numerical tests are presented to verify the theoretical analysis.

  6. Simulation of Local Tie Accuracy on VLBI Antennas

    Science.gov (United States)

    Kallio, Ulla; Poutanen, Markku

    2010-01-01

    We introduce a new mathematical model to compute the centering parameters of a VLBI antenna. These include the coordinates of the reference point, axis offset, orientation, and non-perpendicularity of the axes. Using the model we simulated how precisely parameters can be computed in different cases. Based on the simulation we can give some recommendations and practices to control the accuracy and reliability of the local ties at the VLBI sites.

  7. Why is a high accuracy needed in dosimetry. [Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lanzl, L.H.

    1976-01-01

    Dose and exposure intercomparisons on a national or international basis have become an important component of quality assurance in the practice of good radiotherapy. A high degree of accuracy of ..gamma.. and x radiation dosimetry is essential in our international society, where medical information is so readily exchanged and used. The value of accurate dosimetry lies mainly in the avoidance of complications in normal tissue and an optimal degree of tumor control.

  8. The Accuracy of RADIANCE Software in Modelling Overcast Sky Condition

    OpenAIRE

    Baharuddin

    2013-01-01

    A validation study of the sky models of RADIANCE simulation software against the overcast sky condition has been carried out in order to test the accuracy of sky model of RADIANCE for modeling the overcast sky condition in Hong Kong. Two sets of data have been analysed. Firstly, data collected from a set of experiments using a physical scale model. In this experiment, the illuminance of four points inside the model was measured under real sky conditions. Secondly, the RADIANCE simulation has ...

  9. Method for Improving the Ranging Accuracy of Radio Fuze

    Institute of Scientific and Technical Information of China (English)

    HU Xiu-juan; DENG Jia-hao; SANG Hui-ping

    2006-01-01

    Stepped frequency radar waveform is put forward for improving the accuracy of radio fuze ranging. IFFT is adopted to synthesize one dimension high resolution range profile. Furthermore, the same range reject method and selection maximum method are made use of removing target redundancy and the simulation results are given. Characters of the two methods are analyzed, and under the proposal of Weibull distribution clutter envelope, the CFAR same range selection maximum method is adopted and realizes the accurate profile and ranging.

  10. [Castability and accuracy of fit of a titanium casting system].

    Science.gov (United States)

    Klinger, E; Böning, K; Walter, M

    1991-11-01

    The titanium casting system Cyclarc (Morita) was examined for its suitability for the fabrication of dense, fitting restorations. The investment material Titavest CB exhibited no setting expansion. Instead, thermal expansion, highly dependent on the liquid/power ratio and the temperature during preheating, was observed. The castability of unalloyed titanium is fully acceptable for the fabrication of prosthetic restorations. Single crowns showed a high accuracy of fit, if an optimal liquid/power ratio was used for investment.

  11. One Advanced Indoor Localization Algorithm for Improving Localization Accuracy

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Chao

    2013-01-01

    The indoor localization technology has very important practical value for real-time monitoring and management of indoor materials.In order to achieve localization for indoor substances,a model of indoor localization algorithm based on distances is established,meanwhile,DFP algorithm is introduced to further refine the positioning coordinates and improve the localization accuracy.The main idea is using the least squares estimation method and cubic spline interpolation to

  12. Spatial Sampling Strategies for the Effect of Interpolation Accuracy

    Directory of Open Access Journals (Sweden)

    Hairong Zhang

    2015-12-01

    Full Text Available Spatial interpolation methods are widely used in various fields and have been studied by several scholars with one or a few specific sampling datasets that do not reflect the complexity of the spatial characteristics and lead to conclusions that cannot be widely applied. In this paper, three factors that affect the accuracy of interpolation have been considered, i.e., sampling density, sampling mode, and sampling location. We studied the inverse distance weighted (IDW, regular spline (RS, and ordinary kriging (OK interpolation methods using 162 DEM datasets considering six sampling densities, nine terrain complexities, and three sampling modes. The experimental results show that, in selective sampling and combined sampling, the maximum absolute errors of interpolation methods rapidly increase and the estimated values are overestimated. In regular-grid sampling, the RS method has the highest interpolation accuracy, and IDW has the lowest interpolation accuracy. However, in both selective and combined sampling, the accuracy of the IDW method is significantly improved and the RS method performs worse. The OK method does not significantly change between the three sampling modes. The following conclusion can be obtained from the above analysis: the combined sampling mode is recommended for sampling, and more sampling points should be added in the ridges, valleys, and other complex terrain. The IDW method should not be used in the regular-grid sampling mode, but it has good performance in the selective sampling mode and combined sampling mode. However, the RS method shows the opposite phenomenon. The sampling dataset should be analyzed before using the OK method, which can select suitable models based on the analysis results of the sampling dataset.

  13. Accuracy of stream habitat interpolations across spatial scales

    Science.gov (United States)

    Sheehan, Kenneth R.; Welsh, Stuart

    2013-01-01

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

  14. The National Shipbuilding Research Program. Process Analysis Via Accuracy Control

    Science.gov (United States)

    1985-08-01

    Process Analysis Via Accuracy Control U.S. DEPARTMENT OF TRANSPORTATION Maritime Administration in cooperation with Todd Pacific Shipyards...AUG 1985 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE The National Shipbuilding Research Program Process Analysis Via...lighting, retraining work- ers, or other such approaches. This product of A/C is called process or method analysis. Process analysis involves a

  15. Assessing the Accuracy of Prediction Algorithms for Classification

    DEFF Research Database (Denmark)

    Baldi, P.; Brunak, Søren; Chauvin, Y.;

    2000-01-01

    We provide a unified overview of methods that currently are widely used to assess the accuracy of prediction algorithms, from raw percentages, quadratic error measures and other distances, ann correlation coefficients, and to information theoretic measures such as relative entropy and mutual...... information. We briefly discuss the advantages and disadvantages of each approach. For classification tasks, we derive new learning algorithms for the design of prediction systems by directly optimising the correlation coefficient. We observe and prove several results relating sensitivity nod specificity...

  16. Systematic reviews and meta-analyses of diagnostic test accuracy.

    Science.gov (United States)

    Leeflang, M M G

    2014-02-01

    Systematic reviews of diagnostic test accuracy summarize the accuracy, e.g. the sensitivity and specificity, of diagnostic tests in a systematic and transparent way. The aim of such a review is to investigate whether a test is sufficiently specific or sensitive to fit its role in practice, to compare the accuracy of two or more diagnostic tests, or to investigate where existing variation in results comes from. The search strategy should be broad and preferably fully reported, to enable readers to assess the completeness of it. Included studies usually have a cross-sectional design in which the tests of interest, ideally both the index test and its comparator, are evaluated against the reference standard. They should be a reflection of the situation that the review question refers to. The quality of included studies is assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 checklist, containing items such as a consecutive and all-inclusive patient selection process, blinding of index test and reference standard assessment, a valid reference standard, and complete verification of all included participants. Studies recruiting cases separately from (healthy) controls are regarded as bearing a high risk of bias. For meta-analysis, the bivariate model or the hierarchical summary receiver operating characteristic model is used. These models take into account potential threshold effects and the correlation between sensitivity and specificity. They also allow addition of covariates for investigatation of potential sources of heterogeneity. Finally, the results from the meta-analyses should be explained and interpreted for the reader, to be well understood.

  17. Calibration of Robot Reference Frames for Enhanced Robot Positioning Accuracy

    OpenAIRE

    Cheng, Frank Shaopeng

    2008-01-01

    This chapter discussed the importance and methods of conducting robot workcell calibration for enhancing the accuracy of the robot TCP positions in industrial robot applications. It shows that the robot frame transformations define the robot geometric parameters such as joint position variables, link dimensions, and joint offsets in an industrial robot system. The D-H representation allows the robot designer to model the robot motion geometry with the four standard D-H parameters. The robot k...

  18. On the accuracy of the asymptotic theory for cylindrical shells

    DEFF Research Database (Denmark)

    Niordson, Frithiof; Niordson, Christian

    1999-01-01

    We study the accuracy of the lowest-order bending theory of shells, derived from an asymptotic expansion of the three-dimensional theory of elasticity, by comparing the results of this shell theory for a cylindrical shell with clamped ends with the results of a solution to the three......-dimensional problem. The results are also compared with those of some commonly used engineering shell theories....

  19. The accuracy of Root ZX electronic apex locator

    OpenAIRE

    Osama S Alothmani

    2012-01-01

    The aim of this review was to evaluate studies assessing the accuracy of Root ZX when used for working length determination in permanent teeth and to identify factors affecting the device′s precision. An electronic search for articles published in English language since 1994 was conducted on the Medline via Ovid interface. All issues of the International Endodontic Journal, Journal of Endodontics and Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology since 1994 were...

  20. The Move from Accuracy Studies to Randomized Trials in PET

    DEFF Research Database (Denmark)

    Siepe, Bettina; Hoilund-Carlsen, Poul Flemming; Gerke, Oke

    2014-01-01

    an important role in informing guideline developers and policy makers. Our aim was to investigate how far the nuclear medicine community has come on its way from accuracy studies to RCTs and which issues we have to take into account in planning future studies. METHODS: We conducted a systematic review...... evaluation. Choice of patient-important outcomes and sufficient sample sizes are crucial issues in planning RCTs to demonstrate the clinical benefit of using PET....

  1. Factors Affecting Accuracy of Data Abstracted from Medical Records.

    Directory of Open Access Journals (Sweden)

    Meredith N Zozus

    Full Text Available Medical record abstraction (MRA is often cited as a significant source of error in research data, yet MRA methodology has rarely been the subject of investigation. Lack of a common framework has hindered application of the extant literature in practice, and, until now, there were no evidence-based guidelines for ensuring data quality in MRA. We aimed to identify the factors affecting the accuracy of data abstracted from medical records and to generate a framework for data quality assurance and control in MRA.Candidate factors were identified from published reports of MRA. Content validity of the top candidate factors was assessed via a four-round two-group Delphi process with expert abstractors with experience in clinical research, registries, and quality improvement. The resulting coded factors were categorized into a control theory-based framework of MRA. Coverage of the framework was evaluated using the recent published literature.Analysis of the identified articles yielded 292 unique factors that affect the accuracy of abstracted data. Delphi processes overall refuted three of the top factors identified from the literature based on importance and five based on reliability (six total factors refuted. Four new factors were identified by the Delphi. The generated framework demonstrated comprehensive coverage. Significant underreporting of MRA methodology in recent studies was discovered.The framework generated from this research provides a guide for planning data quality assurance and control for studies using MRA. The large number and variability of factors indicate that while prospective quality assurance likely increases the accuracy of abstracted data, monitoring the accuracy during the abstraction process is also required. Recent studies reporting research results based on MRA rarely reported data quality assurance or control measures, and even less frequently reported data quality metrics with research results. Given the demonstrated

  2. Bias due to composite reference standards in diagnostic accuracy studies.

    Science.gov (United States)

    Schiller, Ian; van Smeden, Maarten; Hadgu, Alula; Libman, Michael; Reitsma, Johannes B; Dendukuri, Nandini

    2016-04-30

    Composite reference standards (CRSs) have been advocated in diagnostic accuracy studies in the absence of a perfect reference standard. The rationale is that combining results of multiple imperfect tests leads to a more accurate reference than any one test in isolation. Focusing on a CRS that classifies subjects as disease positive if at least one component test is positive, we derive algebraic expressions for sensitivity and specificity of this CRS, sensitivity and specificity of a new (index) test compared with this CRS, as well as the CRS-based prevalence. We use as a motivating example the problem of evaluating a new test for Chlamydia trachomatis, an asymptomatic disease for which no gold-standard test exists. As the number of component tests increases, sensitivity of this CRS increases at the expense specificity, unless all tests have perfect specificity. Therefore, such a CRS can lead to significantly biased accuracy estimates of the index test. The bias depends on disease prevalence and accuracy of the CRS. Further, conditional dependence between the CRS and index test can lead to over-estimation of index test accuracy estimates. This commonly-used CRS combines results from multiple imperfect tests in a way that ignores information and therefore is not guaranteed to improve over a single imperfect reference unless each component test has perfect specificity, and the CRS is conditionally independent of the index test. When these conditions are not met, as in the case of C. trachomatis testing, more realistic statistical models should be researched instead of relying on such CRSs.

  3. Evaluation of registration accuracy between Sentinel-2 and Landsat 8

    Science.gov (United States)

    Barazzetti, Luigi; Cuca, Branka; Previtali, Mattia

    2016-08-01

    Starting from June 2015, Sentinel-2A is delivering high resolution optical images (ground resolution up to 10 meters) to provide a global coverage of the Earth's land surface every 10 days. The planned launch of Sentinel-2B along with the integration of Landsat images will provide time series with an unprecedented revisit time indispensable for numerous monitoring applications, in which high resolution multi-temporal information is required. They include agriculture, water bodies, natural hazards to name a few. However, the combined use of multi-temporal images requires an accurate geometric registration, i.e. pixel-to-pixel correspondence for terrain-corrected products. This paper presents an analysis of spatial co-registration accuracy for several datasets of Sentinel-2 and Landsat 8 images distributed all around the world. Images were compared with digital correlation techniques for image matching, obtaining an evaluation of registration accuracy with an affine transformation as geometrical model. Results demonstrate that sub-pixel accuracy was achieved between 10 m resolution Sentinel-2 bands (band 3) and 15 m resolution panchromatic Landsat images (band 8).

  4. Accuracy of Hepatobiliary Scintigraphy after Liver Transplantation and Liver Resection

    Directory of Open Access Journals (Sweden)

    Manuel Eckenschwiller

    2016-01-01

    Full Text Available Background and Aims. Biliary complications are the most frequent complications after common liver surgeries. In this study, accuracy of hepatobiliary scintigraphy (HBS and impact of hyperbilirubinemia were evaluated. Methods. Between November 2007 and February 2016, 131 patients underwent hepatobiliary scintigraphy after having liver surgery. 39 patients with 42 scans after LTX (n=13 or hepatic resection (n=26 were evaluated in the study; 27 were male, with mean age 60 years. The subjects underwent hepatobiliary scintigraphy with Tc-99m labeled Mebrofenin. The results were compared to ERCP as gold standard performed within one month after HBS. We calculated sensitivity, specificity, PPV, and NPV. We compared LTX patients to patients with other liver surgeries. Furthermore the influence of hyperbilirubinemia on HBS scans was evaluated. Results. HBS always provided the correct diagnosis in cases of bile leak in the liver-resected group (14/14. Overall diagnostic accuracy was 76% (19/25 in this group and 54% (7/13 in the LTX group. False negative (FN diagnoses occurred more often among LTX patients (p=0.011. Hyperbilirubinemia (>5 mg/dL significantly influenced the excretion function of the liver, prolonging HBS’s time-activity-curve (p=0.001. Conclusions. Hepatobiliary scintigraphy is a reliable tool to detect biliary complications, but reduced accuracy must be considered after LTX.

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

    Science.gov (United States)

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

    2012-05-01

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

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

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    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.

  7. Culture and Probability Judgment Accuracy: The Influence of Holistic Reasoning.

    Science.gov (United States)

    Lechuga, Julia; Wiebe, John S

    2011-08-01

    A well-established phenomenon in the judgment and decision-making tradition is the overconfidence one places in the amount of knowledge that one possesses. Overconfidence or probability judgment accuracy varies not only individually but also across cultures. However, research efforts to explain cross-cultural variations in the overconfidence phenomenon have seldom been made. In Study 1, the authors compared the probability judgment accuracy of U.S. Americans (N = 108) and Mexican participants (N = 100). In Study 2, they experimentally primed culture by randomly assigning English/Spanish bilingual Mexican Americans (N = 195) to response language. Results of both studies replicated the cross-cultural variation of probability judgment accuracy previously observed in other cultural groups. U.S. Americans displayed less overconfidence when compared to Mexicans. These results were then replicated in bilingual participants, when culture was experimentally manipulated with language priming. Holistic reasoning did not account for the cross-cultural variation of overconfidence. Suggestions for future studies are discussed.

  8. Halo Abundance Matching: accuracy and conditions for numerical convergence

    CERN Document Server

    Klypin, Anatoly; Yepes, Gustavo; Hess, Steffen; Gottlober, Stefan

    2013-01-01

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

  9. Meter Accuracy Seafloor Geodesy using Repeated Multibeam Surveys

    Science.gov (United States)

    DeSanto, J. B.; Sandwell, D. T.

    2014-12-01

    Ship-board multibeam surveys are a useful tool in measuring tectonic deformation of the seafloor, having been used to measure the ~50 m of surface slip along the Japan trench during the 2011 Tohoku-Oki earthquake with an uncertainty of 20 m (Fujiwara et al, 2011, Science). In this study, we investigate the improvement in positioning accuracy obtainable when comparing multibeam and sidescan surveys repeated along the same track to within 1/10 of the critical baseline and taken at a slow ship speed of 1 knot. We compare two surveys of the Juan de Fuca Ridge axis fitting these criteria with two coincident surveys of the Cocos Ridge, taken at 11 knots. Both pairs of surveys were collected using a Simrad EM120 sonar system aboard the RV Roger Revelle. We find the multibeam surveys of the Juan de Fuca ridge axis sufficient to measure displacements accurate to better than 2 m, a marked improvement over the 50 m accuracy of the Cocos ridge surveys. Likewise, we can measure displacement accurate to 2 m using the sidescan data from the Juan de Fuca surveys. This accuracy is sufficient to observe meter-level horizontal movements on the deep ocean associated with large earthquakes and landslides.

  10. Exploring the Relationship Between Eye Movements and Electrocardiogram Interpretation Accuracy

    Science.gov (United States)

    Davies, Alan; Brown, Gavin; Vigo, Markel; Harper, Simon; Horseman, Laura; Splendiani, Bruno; Hill, Elspeth; Jay, Caroline

    2016-12-01

    Interpretation of electrocardiograms (ECGs) is a complex task involving visual inspection. This paper aims to improve understanding of how practitioners perceive ECGs, and determine whether visual behaviour can indicate differences in interpretation accuracy. A group of healthcare practitioners (n = 31) who interpret ECGs as part of their clinical role were shown 11 commonly encountered ECGs on a computer screen. The participants’ eye movement data were recorded as they viewed the ECGs and attempted interpretation. The Jensen-Shannon distance was computed for the distance between two Markov chains, constructed from the transition matrices (visual shifts from and to ECG leads) of the correct and incorrect interpretation groups for each ECG. A permutation test was then used to compare this distance against 10,000 randomly shuffled groups made up of the same participants. The results demonstrated a statistically significant (α  0.05) result in 5 of the 11 stimuli demonstrating that the gaze shift between the ECG leads is different between the groups making correct and incorrect interpretations and therefore a factor in interpretation accuracy. The results shed further light on the relationship between visual behaviour and ECG interpretation accuracy, providing information that can be used to improve both human and automated interpretation approaches.

  11. DIAGNOSTIC ACCURACY OF PROVOCATIVE TESTS IN LATERAL EPICONDYLITIS

    Directory of Open Access Journals (Sweden)

    G Saroja

    2014-12-01

    Full Text Available The aim of the present study was to analyze the diagnostic accuracy of the commonly used provocative tests in the diagnosis of lateral epicondylitis (LE. Cozen’s test, Mills test and Maudsley test are most widely used. Till date no studies have been reported on the diagnostic accuracy of these tests. Musculoskeletal ultrasonography serves as a gold standard tool in the diagnosis of LE. Thirty subjects participated in the study. Baseline measurements of pain severity, elbow joint mobility, hand grip strength and three provocative tests were recorded by the principal investigator. A second investigator accompanied the subjects for musculoskeletal ultrasonography who was blinded of the test results. The thickness of common extensor tendon, echo texture and lateral epicondyle bony contour was measured. The test results of the three provocative tests with ultrasonographic findings were analyzed. The sensitivity for Cozen’s test, Maudsley test and Mills test was found to be 84%, 88% and 53% respectively. The specificity for Cozen’s Maudsley and Mills test was found to be 0%, 0% and 100% respectively. Mills test showed significant area under receiver operator curve (ROC i.e. (0.769, which explains that the test has good diagnostic accuracy. This validation study, concludes that Mills test has an excellent diagnostic value for ruling in LE.

  12. Navigation message designing with high accuracy for NAV

    Institute of Scientific and Technical Information of China (English)

    Wang Luxiao; Huang Zhigang; Zhao Yun

    2014-01-01

    Navigation message designing with high accuracy guarantee is the key to efficient navi-gation message distribution in the global navigation satellite system (GNSS). Developing high accu-racy-aware navigation message designing algorithms is an important topic. This paper investigates the high-accuracy navigation message designing problem with the message structure unchanged. The contributions made in this paper include a heuristic that employs the concept of the estimated range deviation (ERD) to improve the existing well-known navigation message on L1 frequency (NAV) of global positioning system (GPS) for good accuracy service; a numerical analysis approximation method (NAAM) to evaluate the range error due to truncation (RET) of different navigation messages; and a basic positioning parameters designing algorithm in the limited space allocation. Based on the predicted ultra-rapid data from the ultra-rapid data from the international GPS service for geodynamic (IGU), ERDs are generated in real time for error correction. Simulations show that the algorithms developed in this paper are general and flexible, and thus are applicable to NAV improvement and other navigation message designs.

  13. Accuracy of stone casts obtained by different impression materials

    Directory of Open Access Journals (Sweden)

    Adriana Cláudia Lapria Faria

    2008-12-01

    Full Text Available Several impression materials are available in the Brazilian marketplace to be used in oral rehabilitation. The aim of this study was to compare the accuracy of different impression materials used for fixed partial dentures following the manufacturers' instructions. A master model representing a partially edentulous mandibular right hemi-arch segment whose teeth were prepared to receive full crowns was used. Custom trays were prepared with auto-polymerizing acrylic resin and impressions were performed with a dental surveyor, standardizing the path of insertion and removal of the tray. Alginate and elastomeric materials were used and stone casts were obtained after the impressions. For the silicones, impression techniques were also compared. To determine the impression materials' accuracy, digital photographs of the master model and of the stone casts were taken and the discrepancies between them were measured. The data were subjected to analysis of variance and Duncan's complementary test. Polyether and addition silicone following the single-phase technique were statistically different from alginate, condensation silicone and addition silicone following the double-mix technique (p .05 to alginate and addition silicone following the double-mix technique, but different from polysulfide. The results led to the conclusion that different impression materials and techniques influenced the stone casts' accuracy in a way that polyether, polysulfide and addition silicone following the single-phase technique were more accurate than the other materials.

  14. Accuracy of stone casts obtained by different impression materials.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Rodrigues, Renata Cristina Silveira; Macedo, Ana Paula; Mattos, Maria da Gloria Chiarello de; Ribeiro, Ricardo Faria

    2008-01-01

    Several impression materials are available in the Brazilian marketplace to be used in oral rehabilitation. The aim of this study was to compare the accuracy of different impression materials used for fixed partial dentures following the manufacturers' instructions. A master model representing a partially edentulous mandibular right hemi-arch segment whose teeth were prepared to receive full crowns was used. Custom trays were prepared with auto-polymerizing acrylic resin and impressions were performed with a dental surveyor, standardizing the path of insertion and removal of the tray. Alginate and elastomeric materials were used and stone casts were obtained after the impressions. For the silicones, impression techniques were also compared. To determine the impression materials' accuracy, digital photographs of the master model and of the stone casts were taken and the discrepancies between them were measured. The data were subjected to analysis of variance and Duncan's complementary test. Polyether and addition silicone following the single-phase technique were statistically different from alginate, condensation silicone and addition silicone following the double-mix technique (p or = .05) to alginate and addition silicone following the double-mix technique, but different from polysulfide. The results led to the conclusion that different impression materials and techniques influenced the stone casts' accuracy in a way that polyether, polysulfide and addition silicone following the single-phase technique were more accurate than the other materials.

  15. Assessment of neuropsychiatric symptoms in dementia: Toward improving accuracy

    Directory of Open Access Journals (Sweden)

    Florindo Stella

    Full Text Available ABSTRACT The issue of this article concerned the discussion about tools frequently used tools for assessing neuropsychiatric symptoms of patients with dementia, particularly Alzheimer's disease. The aims were to discuss the main tools for evaluating behavioral disturbances, and particularly the accuracy of the Neuropsychiatric Inventory - Clinician Rating Scale (NPI-C. The clinical approach to and diagnosis of neuropsychiatric syndromes in dementia require suitable accuracy. Advances in the recognition and early accurate diagnosis of psychopathological symptoms help guide appropriate pharmacological and non-pharmacological interventions. In addition, recommended standardized and validated measurements contribute to both scientific research and clinical practice. Emotional distress, caregiver burden, and cognitive impairment often experienced by elderly caregivers, may affect the quality of caregiver reports. The clinician rating approach helps attenuate these misinterpretations. In this scenario, the NPI-C is a promising and versatile tool for assessing neuropsychiatric syndromes in dementia, offering good accuracy and high reliability, mainly based on the diagnostic impression of the clinician. This tool can provide both strategies: a comprehensive assessment of neuropsychiatric symptoms in dementia or the investigation of specific psychopathological syndromes such as agitation, depression, anxiety, apathy, sleep disorders, and aberrant motor disorders, among others.

  16. Impact of Orthodontic Brackets on the Intraoral Scan Data Accuracy

    Directory of Open Access Journals (Sweden)

    Ji-Man Park

    2016-01-01

    Full Text Available This study aims to compare the impact of buccal and lingual brackets on the accuracy of dental arch data acquired by 4 different digital intraoral scanners. Two pairs of dental casts, one with buccal brackets and the other with lingual brackets, were used. Digital measurements of the 3D images were compared to the actual measurements of the dental models, which were considered standard values. The horizontal measurements included intercanine widths and intermolar widths. The Mann–Whitney U test was performed for comparisons. iTero® and Trios® both showed high accuracy with relatively small maximum deviation of measurements. iTero showed a significantly higher accuracy in most of the arch width measurements on the buccal bracket model than on the lingual model (P<0.05. Zfx IntraScan® and E4D Dentist® produced maximum deviations of more than 2 mm from both the buccal and the lingual bracket models. After comparing the degree of distortion of the arch on the digital scans with actual measurements of the same models, iTero and Trios proved to be excellent in terms of trueness and precision. Nevertheless, digital intraoral scanners should be used more cautiously in arches with lingual brackets than in those with buccal brackets.

  17. Morphological Awareness and Children's Writing: Accuracy, Error, and Invention.

    Science.gov (United States)

    McCutchen, Deborah; Stull, Sara

    2015-02-01

    This study examined the relationship between children's morphological awareness and their ability to produce accurate morphological derivations in writing. Fifth-grade U.S. students (n = 175) completed two writing tasks that invited or required morphological manipulation of words. We examined both accuracy and error, specifically errors in spelling and errors of the sort we termed morphological inventions, which entailed inappropriate, novel pairings of stems and suffixes. Regressions were used to determine the relationship between morphological awareness, morphological accuracy, and spelling accuracy, as well as between morphological awareness and morphological inventions. Linear regressions revealed that morphological awareness uniquely predicted children's generation of accurate morphological derivations, regardless of whether or not accurate spelling was required. A logistic regression indicated that morphological awareness was also uniquely predictive of morphological invention, with higher morphological awareness increasing the probability of morphological invention. These findings suggest that morphological knowledge may not only assist children with spelling during writing, but may also assist with word production via generative experimentation with morphological rules during sentence generation. Implications are discussed for the development of children's morphological knowledge and relationships with writing.

  18. Stability and accuracy control of k · p parameters

    Science.gov (United States)

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

    2016-10-01

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

  19. Optimization of speed and accuracy of decoding in translation.

    Science.gov (United States)

    Wohlgemuth, Ingo; Pohl, Corinna; Rodnina, Marina V

    2010-11-03

    The speed and accuracy of protein synthesis are fundamental parameters for understanding the fitness of living cells, the quality control of translation, and the evolution of ribosomes. In this study, we analyse the speed and accuracy of the decoding step under conditions reproducing the high speed of translation in vivo. We show that error frequency is close to 10⁻³, consistent with the values measured in vivo. Selectivity is predominantly due to the differences in k(cat) values for cognate and near-cognate reactions, whereas the intrinsic affinity differences are not used for tRNA discrimination. Thus, the ribosome seems to be optimized towards high speed of translation at the cost of fidelity. Competition with near- and non-cognate ternary complexes reduces the rate of GTP hydrolysis in the cognate ternary complex, but does not appreciably affect the rate-limiting tRNA accommodation step. The GTP hydrolysis step is crucial for the optimization of both the speed and accuracy, which explains the necessity for the trade-off between the two fundamental parameters of translation.

  20. 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.

  1. Solving the Accuracy Metrics and Diversity Measures For Personalised Recommendation

    Directory of Open Access Journals (Sweden)

    I. Jenitta Magdalene,

    2014-01-01

    Full Text Available In the vast amount of information in the internet, to give individual attention for each users, the personalised recommendation system is used, which uses the collaborative filtering method. By the result of the survey did with some papers, the main problems like the cold start and the sparsity which were found previously have been overcome. Filtering the users when the number is large is done by the nearest neighbour approach or by the filtration approach. Due to some popular objects the accuracy of the data's are lost. To remove this influence, the method which is proposed here is a network based collaborative filtering which will create a user similarity network, where the users having similar interests of item or movies will be grouped together forming a network. Then we calculate discriminant scores for candidate objects. Validate the proposed approach by performing random sub-sampling experiments for about 20 times to get the accurate results and evaluate the method using two accuracy criteria and two diversity measures. Results show that the approach outperforms the ordinary user-based collaborative filtering method by not only enhancing the accuracy but also improving the diversity.

  2. Diagnostic accuracy of insight intraoral film on dental caries

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Young Nam; Lee, Byung Do [Wonkwang University College of Medicine, Iksan (Korea, Republic of); Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    2004-03-15

    To compare the diagnostic accuracy of Kodak Insight film with other intra-oral films in the detection of dental caries. Periapical radiographs of 99 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were made on Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Kodak Insight films and automatically processed. Six dentists examined the presence of dental caries using a five-point confidence rating scale and compared the diagnostic accuracy by ROC (Receiver Operating Characteristic) analysis and ANOVA test. The sensitivity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.84, 0.77, 0.75 and 0.79 respectively. The specificity of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.97, 0.95, 0.96 and 0.94 respectively. The mean ROC areas (Az) of Kodak Ultra speed, Ektaspeed, Agfa Ektaspeed and Insight film were 0.917, 0.910, 0.894, 0.909 respectively. There was no significant differences between Az of Insight film and other films (p = 0.178). Theses results suggested that Kodak Insight film have the comparative diagnostic accuracy of dental caries with Ultraspeed and Ektaspeed films. (77)

  3. RADIOMETRIC AND GEOMETRIC ACCURACY ANALYSIS OF RASAT PAN IMAGERY

    Directory of Open Access Journals (Sweden)

    S. Kocaman

    2016-06-01

    Full Text Available RASAT is the second Turkish Earth Observation satellite which was launched in 2011. It operates with pushbroom principle and acquires panchromatic and MS images with 7.5 m and 15 m resolutions, respectively. The swath width of the sensor is 30 km. The main aim of this study is to analyse the radiometric and geometric quality of RASAT images. A systematic validation approach for the RASAT imagery and its products is being applied. RASAT image pair acquired over Kesan city in Edirne province of Turkey are used for the investigations. The raw RASAT data (L0 are processed by Turkish Space Agency (TUBITAK-UZAY to produce higher level image products. The image products include radiometrically processed (L1, georeferenced (L2 and orthorectified (L3 data, as well as pansharpened images. The image quality assessments include visual inspections, noise, MTF and histogram analyses. The geometric accuracy assessment results are only preliminary and the assessment is performed using the raw images. The geometric accuracy potential is investigated using 3D ground control points extracted from road intersections, which were measured manually in stereo from aerial images with 20 cm resolution and accuracy. The initial results of the study, which were performed using one RASAT panchromatic image pair, are presented in this paper.

  4. APPROACH TO IMPROVEMENT OF ROBOT TRAJECTORY ACCURACY BY DYNAMIC COMPENSATION

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Ren Guoli; Yan Xiang'an; Wang Guodong

    2004-01-01

    Some dynamic factors, such as inertial forces and friction, may affect the robot trajectory accuracy. But these effects are not taken into account in robot motion control schemes. Dynamic control methods, on the other hand, require the dynamic model of robot and the implementation of new type controller. A method to improve robot trajectory accuracy by dynamic compensation in robot motion control system is proposed. The dynamic compensation is applied as an additional velocity feedforward and a multilayer neural network is employed to realize the robot inverse dynamics. The complicated dynamic parameter identification problem becomes a learning process of neural network connecting weights under supervision. The finite Fourier series is used to activate each actuator of robot joints for obtaining training samples. Robot control system, consisting of an industrial computer and a digital motion controller, is implemented. The system is of open architecture with velocity feedforward function. The proposed method is not model-based and combines the advantages of close-loop position control and computed torque control. Experimental results have shown that the method is validatities to improve the robot trajectory accuracy.

  5. High Accuracy Monocular SFM and Scale Correction for Autonomous Driving.

    Science.gov (United States)

    Song, Shiyu; Chandraker, Manmohan; Guest, Clark C

    2016-04-01

    We present a real-time monocular visual odometry system that achieves high accuracy in real-world autonomous driving applications. First, we demonstrate robust monocular SFM that exploits multithreading to handle driving scenes with large motions and rapidly changing imagery. To correct for scale drift, we use known height of the camera from the ground plane. Our second contribution is a novel data-driven mechanism for cue combination that allows highly accurate ground plane estimation by adapting observation covariances of multiple cues, such as sparse feature matching and dense inter-frame stereo, based on their relative confidences inferred from visual data on a per-frame basis. Finally, we demonstrate extensive benchmark performance and comparisons on the challenging KITTI dataset, achieving accuracy comparable to stereo and exceeding prior monocular systems. Our SFM system is optimized to output pose within 50 ms in the worst case, while average case operation is over 30 fps. Our framework also significantly boosts the accuracy of applications like object localization that rely on the ground plane.

  6. Estimated Accuracy of Three Common Trajectory Statistical Methods

    Science.gov (United States)

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

    2011-01-01

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

  7. AN EVALUATION OF USA UNEMPLOYMENT RATE FORECASTS IN TERMS OF ACCURACY AND BIAS. EMPIRICAL METHODS TO IMPROVE THE FORECASTS ACCURACY

    Directory of Open Access Journals (Sweden)

    BRATU (SIMIONESCU MIHAELA

    2013-02-01

    Full Text Available The most accurate forecasts for USA unemployment rate on the horizon 2001-2012, according to U1 Theil’s coefficient and to multi-criteria ranking methods, were provided by International Monetary Fund (IMF, being followed by other institutions as: Organization for Economic Co-operation and Development (OECD, Congressional Budget Office (CBO and Blue Chips (BC. The multi-criteria ranking methods were applied to solve the divergence in assessing the accuracy, differences observed by computing five chosen measures of accuracy: U1 and U2 statistics of Theil, mean error, mean squared error, root mean squared error. Some strategies of improving the accuracy of the predictions provided by the four institutions, which are biased in all cases, excepting BC, were proposed. However, these methods did not generate unbiased forecasts. The predictions made by IMF and OECD for 2001-2012 can be improved by constructing combined forecasts, the INV approach and the scheme proposed by author providing the most accurate expections. The BC forecasts can be improved by smoothing the predictions using Holt-Winters method and Hodrick - Prescott filter.

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

    Science.gov (United States)

    Xu, X. Q.

    2015-09-01

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

  9. Accuracy and Reliability of a New Tennis Ball Machine

    Directory of Open Access Journals (Sweden)

    Cyril Brechbuhl, Grégoire Millet, Laurent Schmitt

    2016-06-01

    Full Text Available The aim was to evaluate the reliability of a newly-developed ball machine named 'Hightof', on the field and to assess its accuracy. The experiment was conducted in the collaboration of the 'Hawk-Eye' technology. The accuracy and reliability of this ball machine were assessed during an incremental test, with 1 min of exercise and 30 sec of recovery, where the frequency of the balls increased from 10 to 30 balls·min-1. The initial frequency was 10 and increased by 2 until 22, then by 1 until 30 balls·min-1. The reference points for the impact were 8.39m from the net and 2.70m from lateral line for the right side and 2.83m for the left side. The precision of the machine was similar on the right and left sides (0.63 ± 0.39 vs 0.63 ± 0.34 m. The distances to the reference point were 0.52 ± 0.42, 0.26 ± 0.19, 0.52 ± 0.37, 0.28 ± 0.19 m for the Y-right, X-right, Y-left and X-left impacts. The precision was constant and did not increase with the intensity. (e.g ball frequency. The ball velocity was 86.3 ± 1.5 and 86.5 ± 1.3 km·h-1 for the right and the left side, respectively. The coefficient of variation for the velocity ranged between 1 and 2% in all stages (ball velocity ranging from 10 to 30 balls·min-1. Conclusion: both the accuracy and the reliability of this new ball machine appear satisfying enough for field testing and training.

  10. Using Transponders on the Moon to Increase Accuracy of GPS

    Science.gov (United States)

    Penanen, Konstantin; Chui, Talso

    2008-01-01

    It has been proposed to place laser or radio transponders at suitably chosen locations on the Moon to increase the accuracy achievable using the Global Positioning System (GPS) or other satellite-based positioning system. The accuracy of GPS position measurements depends on the accuracy of determination of the ephemerides of the GPS satellites. These ephemerides are determined by means of ranging to and from Earth-based stations and consistency checks among the satellites. Unfortunately, ranging to and from Earth is subject to errors caused by atmospheric effects, notably including unpredictable variations in refraction. The proposal is based on exploitation of the fact that ranging between a GPS satellite and another object outside the atmosphere is not subject to error-inducing atmospheric effects. The Moon is such an object and is a convenient place for a ranging station. The ephemeris of the Moon is well known and, unlike a GPS satellite, the Moon is massive enough that its orbit is not measurably affected by the solar wind and solar radiation. According to the proposal, each GPS satellite would repeatedly send a short laser or radio pulse toward the Moon and the transponder(s) would respond by sending back a pulse and delay information. The GPS satellite could then compute its distance from the known position(s) of the transponder(s) on the Moon. Because the same hemisphere of the Moon faces the Earth continuously, any transponders placed there would remain continuously or nearly continuously accessible to GPS satellites, and so only a relatively small number of transponders would be needed to provide continuous coverage. Assuming that the transponders would depend on solar power, it would be desirable to use at least two transponders, placed at diametrically opposite points on the edges of the Moon disk as seen from Earth, so that all or most of the time, at least one of them would be in sunlight.

  11. Effect of storage period on the accuracy of elastomeric impressions

    Directory of Open Access Journals (Sweden)

    Eduardo Batista Franco

    2007-06-01

    Full Text Available AIMS: To investigate the effect of the storage period on the accuracy of recently developed elastomeric materials. METHODS: Simultaneous impressions of a steel die were taken using a polyether (I: Impregum Soft Heavy and Light body, 3M ESPE and vinyl polysiloxane (P: Perfectim Blue Velvet and Flexi-Velvet, J.Morita. The trays were loaded with the heavy-bodied impression materials while the light-bodied impression materials were simultaneously spread on the steel die. The impressions were poured after 2 hours, 24 hours, and 7 days. Impressions were stored at approximately 55% relative humidity and room temperature. Ten replicas were produced for each experimental condition (n=60. Accuracy of the stone dies was assessed with a depth-measuring microscope. The difference in height between the surface of the stone die and a standard metallic ring was recorded in micrometers at four demarcated points, by two independent examiners. Data were submitted to two-way ANOVA and Tukey test (a = 0.05. RESULTS: Significant differences were found among the groups. Smaller discrepancies were observed when pouring was performed up to 24 hours (I-2h= 65.0 ± 15.68 µm; I-24h= 81.6 ± 11.13 µm for the polyether, and up to 7 days for the vinyl polysiloxane (P-2h= 79.1 ± 13.82 µm; P-24h= 96.8 ± 6.02 µm; P-7d= 81.4 ± 4.3 µm. Significant dimensional discrepancies, however, were observed when polyether was stored for 7 days (I-7d= 295.3 ± 17.4 µm. CONCLUSION: Storage may significantly affect the dimensional accuracy of impressions and, thus, a maximum period and storage condition should be specified for the recently developed materials.

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

    Science.gov (United States)

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

    2011-12-01

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

  13. Comparative accuracy of radiostereometric and optical tracking systems.

    Science.gov (United States)

    Kedgley, Angela E; Birmingham, Trevor; Jenkyn, Thomas R

    2009-06-19

    This study aims to quantify and compare the accuracy of traditional radiostereometric analysis (RSA), fluoroscopic RSA (fRSA), and optical tracking systems. Three phantoms were constructed, each having three stainless steel spheres and three reflective markers. One phantom was mounted to the base of a precision cross-slide table, one to the base of a precision rotation table, and the third was mounted to each moveable tabletop. Two dial-gauges, rigidly mounted to the cross-slide table and rotation table, quantified translations and rotations. Two fluoroscopy units placed orthogonally tracked the steel spheres while a four-camera optical motion capture system tracked the reflective markers in three-dimensional space. RSA was performed with both digital radiography and fluoroscopy. Three axes of translation were tested: parallel to one fluoroscopy image, parallel to the other fluoroscopy image, and at approximately 45 degrees to each image. One axis of rotation was tested. Intraclass correlation coefficients indicated excellent agreement between the actual (dial-gauge) and measured translations for all modalities (ICCs>0.99) and excellent agreement between actual and measured rotations for RSA and fRSA (ICCs>0.99). Standard errors of measurement ranged from 0.032 mm and 0.121 degrees for RSA, to 0.040 mm and 0.229 degrees for fRSA, and to 0.109 mm and 0.613 degrees for optical tracking. Differences between actual and measured translations along the 45 degrees axis were significantly smaller than the two parallel axes. These findings suggest that under ideal conditions, accuracy of fRSA is comparable to traditional RSA, and superior to optical tracking. Accuracy is highest when measured at 45 degrees to the fluoroscopy units.

  14. Diagnostic accuracy of CT scan in abdominal blunt trauma

    Institute of Scientific and Technical Information of China (English)

    Javad Salimi; Khadyjeh Bakhtavar; Mehdi Solimani; Patrcia Khashayar; Ali Pasha Meysamie; Moosa Zargar

    2009-01-01

    Obiective: To evaluate the sensitivity and specificity of CT scan findings in Patients ith blunt abdominal trauma admitted to the university hospital.Methods: All the atients ith blunt abdominal trauma admitted at a tertiary teaching trauma center in Iran between 2005 and 2007 were enrolled in this study.In the absence of any clinical anifestations,he patients underwent a diagnostic CT scan.Laparatomy was performed in those with positive CT results.Others were observed for 48 hours and discharged in case no problem as reported;otherwise they underwent laparatomy.Information on patients'demographic ata,mechanism of trauma,indication for CT scan,CT scan findings,results of laparotomy ere gathered.The sensitivity,specificity and accuracy of the CT-scan images in regard ith the organ injured were calculated.The sensitivity,specificity and accuracy of the T scan were calculated in each case.Results: CT Scan had the highest sensitivity for etecting the injuries to liver (100%) and spleen (86.6%).The specificity of the method or detecting retroperitoneal hematoma (100%) and injuries to kidney (93.5%) was higher han other organs.The accuracy of CT images to detect the injuries to spleen,liver,idney and retroperitoneal hematoma was reported to be 96.1%,94.4%,91.6% and 91.6% espectively.Conclusion: The findings of the present study reveal that CT scan could econsidered as a good choice,especially for patients with blunt abdominal trauma in eaching hospitals where the radiologic academic staff is not present in the hospital in the night shifts.

  15. Diagnostic Accuracy of Ultrasound in Detection of Traumatic Lens Dislocation

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Ojaghi Haghighi

    2014-08-01

    Full Text Available Introduction: Traumatic eye injuries (TEI involved about 3% of cases referred to the emergency departments of developing countries. Lens dislocation is one of the critical cases of ophthalmic emergencies. The present study was aimed to evaluate the diagnostic accuracy of ultrasonography in detection of traumatic lens dislocation. Methods: In this cross-sectional study the findings of ultrasonography and orbital computed tomography (OCT of head and face trauma patients, referred to Imam Reza hospital, Tabriz, Iran, from July 2013 to June 2014, have been compared. The sensitivity, specificity, positive and negative likelihood ratio, positive and negative predictive value, and accuracy of ultrasonography were calculated. Cohen's kappa coefficient was presented to assess the agreement of ultrasonography with OCT findings. Results: One hundred thirty patients with the mean age of 35.4±18.0 were evaluated (75.4% male. Sensitivity and specificity of ultrasonography were 84.6% (95% Cl: 53.7-97.3 and 98.3% (95% Cl: 93.3- 99.7, respectively. Also, positive and negative likelihood ratio were calculated 49.5 (95% Cl: 12.3-199.4 and 0.15 (95% Cl: 0.04- 0.56, respectively. Cohen's kappa coefficient of 0.83 (95% Cl: 0.66-1.0; p<0.0001 was representative of excellent agreement of these two tests. Conclusion: The finding of this project was representative of 84.6% sensitivity, 98.3% specificity, and 96.9% accuracy of ultrasonography in detection of traumatic lens dislocation. It seems that in cases which OCT is not possible, ultrasonography could be an acceptable option to assess traumatic eye injuries.

  16. Flush-mounted hot film anemometer accuracy in pulsatile flow.

    Science.gov (United States)

    Nandy, S; Tarbell, J M

    1986-08-01

    The accuracy of a flush-mounted hot film anemometer probe for wall shear stress measurements in physiological pulsatile flows was evaluated in fully developed pulsatile flow in a rigid straight tube. Measured wall shear stress waveform based on steady flow anemometer probe calibrations were compared to theoretical wall shear stress waveforms based on well-established theory and measured flow rate waveforms. The measured and theoretical waveforms were in close agreement during systole (average deviation of 14 percent at peak systole). As expected, agreement was poor during diastole because of flow reversal and diminished frequency response at low shear rate.

  17. CGC beyond eikonal accuracy: finite width target effects

    Directory of Open Access Journals (Sweden)

    Altinoluk Tolga

    2016-01-01

    Full Text Available We present a method to systematically include the corrections to the eikonal approximation that are associated with the finite width of the target. The retarded gluon propagator in background field is calculated at next-to-next-to-eikonal (NNE accuracy by using this method. The corrections to the strict eikonal limit of the gluon propagator are found to be Wilson lines decorated by gradients of the background field of the target. The result is then applied to single inclusive gluon production and to single transverse spin asymmetry for a polarized target in pA collisions.

  18. CGC beyond eikonal accuracy: finite width target effects

    Science.gov (United States)

    Altinoluk, Tolga; Armesto, Nestor; Beuf, Guillaume; Moscoso, Alexis

    2016-03-01

    We present a method to systematically include the corrections to the eikonal approximation that are associated with the finite width of the target. The retarded gluon propagator in background field is calculated at next-to-next-to-eikonal (NNE) accuracy by using this method. The corrections to the strict eikonal limit of the gluon propagator are found to be Wilson lines decorated by gradients of the background field of the target. The result is then applied to single inclusive gluon production and to single transverse spin asymmetry for a polarized target in pA collisions.

  19. Low-cost commodity depth sensor comparison and accuracy analysis

    Science.gov (United States)

    Breuer, Timo; Bodensteiner, Christoph; Arens, Michael

    2014-10-01

    Low cost depth sensors have been a huge success in the field of computer vision and robotics, providing depth images even in untextured environments. The same characteristic applies to the Kinect V2, a time-of-flight camera with high lateral resolution. In order to assess advantages of the new sensor over its predecessor for standard applications, we provide an analysis of measurement noise, accuracy and other error sources with the Kinect V2. We examined the raw sensor data by using an open source driver. Further insights on the sensor design and examples of processing techniques are given to completely exploit the unrestricted access to the device.

  20. Required experimental accuracy to select between supersymmetrical models

    Indian Academy of Sciences (India)

    David Grellscheid

    2004-03-01

    We will present a method to decide a priori whether various supersymmetrical scenarios can be distinguished based on sparticle mass data alone. For each model, a scan over all free SUSY breaking parameters reveals the extent of that model's physically allowed region of sparticle-mass-space. Based on the geometrical configuration of these regions in mass-space, it is possible to obtain an estimate of the required accuracy of future sparticle mass measurements to distinguish between the models. We will illustrate this algorithm with an example. Ths talk is based on work done in collaboration with B C Allanach (LAPTH, Annecy) and F Quevedo (DAMTP, Cambridge).

  1. Improvement of CD-SEM mark position measurement accuracy

    Science.gov (United States)

    Kasa, Kentaro; Fukuhara, Kazuya

    2014-04-01

    CD-SEM is now attracting attention as a tool that can accurately measure positional error of device patterns. However, the measurement accuracy can get worse due to pattern asymmetry as in the case of image based overlay (IBO) and diffraction based overlay (DBO). For IBO and DBO, a way of correcting the inaccuracy arising from measurement patterns was suggested. For CD-SEM, although a way of correcting CD bias was proposed, it has not been argued how to correct the inaccuracy arising from pattern asymmetry using CD-SEM. In this study we will propose how to quantify and correct the measurement inaccuracy affected by pattern asymmetry.

  2. 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

  3. Assessing the Accuracy of the Precise Point Positioning Technique

    Science.gov (United States)

    Bisnath, S. B.; Collins, P.; Seepersad, G.

    2012-12-01

    The Precise Point Positioning (PPP) GPS data processing technique has developed over the past 15 years to become a standard method for growing categories of positioning and navigation applications. The technique relies on single receiver point positioning combined with the use of precise satellite orbit and clock information and high-fidelity error modelling. The research presented here uniquely addresses the current accuracy of the technique, explains the limits of performance, and defines paths to improvements. For geodetic purposes, performance refers to daily static position accuracy. PPP processing of over 80 IGS stations over one week results in few millimetre positioning rms error in the north and east components and few centimetres in the vertical (all one sigma values). Larger error statistics for real-time and kinematic processing are also given. GPS PPP with ambiguity resolution processing is also carried out, producing slight improvements over the float solution results. These results are categorised into quality classes in order to analyse the root error causes of the resultant accuracies: "best", "worst", multipath, site displacement effects, satellite availability and geometry, etc. Also of interest in PPP performance is solution convergence period. Static, conventional solutions are slow to converge, with approximately 35 minutes required for 95% of solutions to reach the 20 cm or better horizontal accuracy. Ambiguity resolution can significantly reduce this period without biasing solutions. The definition of a PPP error budget is a complex task even with the resulting numerical assessment, as unlike the epoch-by-epoch processing in the Standard Position Service, PPP processing involving filtering. An attempt is made here to 1) define the magnitude of each error source in terms of range, 2) transform ranging error to position error via Dilution Of Precision (DOP), and 3) scale the DOP through the filtering process. The result is a deeper

  4. Accuracy Analysis of Assembly Success Rate with Monte Carlo Simulations

    Institute of Scientific and Technical Information of China (English)

    仲昕; 杨汝清; 周兵

    2003-01-01

    Monte Carlo simulation was applied to Assembly Success Rate (ASR) analyses.ASR of two peg-in-hole robot assemblies was used as an example by taking component parts' sizes,manufacturing tolerances and robot repeatability into account.A statistic arithmetic expression was proposed and deduced in this paper,which offers an alternative method of estimating the accuracy of ASR,without having to repeat the simulations.This statistic method also helps to choose a suitable sample size,if error reduction is desired.Monte Carlo simulation results demonstrated the feasibility of the method.

  5. On accuracy problems for semi-analytical sensitivity analyses

    DEFF Research Database (Denmark)

    Pedersen, P.; Cheng, G.; Rasmussen, John

    1989-01-01

    The semi-analytical method of sensitivity analysis combines ease of implementation with computational efficiency. A major drawback to this method, however, is that severe accuracy problems have recently been reported. A complete error analysis for a beam problem with changing length is carried ou...... pseudo loads in order to obtain general load equilibrium with rigid body motions. Such a method would be readily applicable for any element type, whether analytical expressions for the element stiffnesses are available or not. This topic is postponed for a future study....

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

    Science.gov (United States)

    Xie, Wei-Qi; Chai, Xin-Sheng

    2017-03-21

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

  7. Error Model and Accuracy Calibration of 5-Axis Machine Tool

    Directory of Open Access Journals (Sweden)

    Fangyu Pan

    2013-08-01

    Full Text Available To improve the machining precision and reduce the geometric errors for 5-axis machinetool, error model and calibration are presented in this paper. Error model is realized by the theory of multi-body system and characteristic matrixes, which can establish the relationship between the cutting tool and the workpiece in theory. The accuracy calibration was difficult to achieve, but by a laser approach-laser interferometer and laser tracker, the errors can be displayed accurately which is benefit for later compensation.

  8. Dimensional accuracy and stability of acrylic resin denture bases.

    Science.gov (United States)

    Huggett, R; Zissis, A; Harrison, A; Dennis, A

    1992-10-01

    Proponents of injection molding systems have claimed a number of benefits over conventional press-pack dough molding systems. The aim of this study was to evaluate a recently developed injection (dry heat) procedure of processing compared with press-pack dough molding utilizing three curing cycles. The dimensional accuracy and stability of acrylic resin bases produced by the two molding procedures were compared. Dimensional changes were assessed over a period of 4 months using an optical comparator. The results demonstrate that baseplates produced by the injection molding procedure exhibit less shrinkage than those produced by the conventional press-pack procedures.

  9. Diagnostic accuracy of the ultrasonography in complicated pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Kyung Soo; Kim, Kun Sang; Park, Soo Soung [Chungang University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Ultrasonography is an invaluable diagnostic method in Obstetrics. It provides safe, speedy and repeatable way to obtain image of normal and abnormal pregnancy. The ultrasonograms of 167 patients with suspicion of complicated pregnancy were analyzed. The results were as follows. 1. 86 patients showed normal ultrasonogram(50.9%). 100% in intrauterine fetal death and gross fetal anomaly, 100% in abnormal fetal position and number, 95% in pregnancy with pelvic mass, 83% in ectopic pregnancy, 81% in abortion, 78% in molar pregnancy, 74% in plancenta previa. 3. Ultrasonic diagnosis of abrupto placenta was difficult. 4. Diagnostic accuracy was 80% in bicornuate uterus and double vagina

  10. Accuracy and completeness of drug information in Wikipedia.

    Science.gov (United States)

    Clauson, Kevin A; Polen, Hyla H; Boulos, Maged N K; Dzenowagis, Joan H

    2008-11-06

    Web 2.0 technologies, where users participate in content production, are increasingly used as informational and educational resources. Wikipedia is frequently cited by students in the healthcare professions. This study compared the accuracy and completeness of drug information in Wikipedia to Medscape Drug Reference, a traditionally-edited resource. Wikipedia answered fewer questions [40.0% vs. 82.5%] (p<0.001) and was less complete (p=0.00076) than Medscape. No gross errors were found in Wikipedia and its content has improved over time.

  11. Diagnostic accuracy of heel pad palpation - A phantom study

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Matteoli, Sara; Wilhjelm, Jens E.;

    2008-01-01

    Falanga torture involves repetitive blunt trauma to the soles of the feet and typically leaves few detectable changes. Reduced elasticity in the heel pads has been reported as characteristic sequelae and palpatory testing of heel pad elasticity is therefore part of medicolegal assessment of alleged...... torture victims. The goal was to test the accuracy of two experienced investigators in determining whether a heel pad model was soft, medium or hard. The skin-to-bone distance in the models varied within the human range....

  12. On precision and accuracy (bias) statements for measurement procedures

    Energy Technology Data Exchange (ETDEWEB)

    Bruckner, L.A.; Hume, M.W.; Delvin, W.L.

    1988-01-01

    Measurement procedures are often required to contain precision and accuracy of precision and bias statements. This paper contains a glossary that explains various terms that often appear in these statements as well as an example illustrating such statements for a specific set of data. Precision and bias statements are shown to vary according to the conditions under which the data were collected. This paper emphasizes that the error model (an algebraic expression that describes how the various sources of variation affect the measurement) is an important consideration in the formation of precision and bias statements.

  13. Comparative evaluation of ultrasound scanner accuracy in distance measurement

    Science.gov (United States)

    Branca, F. P.; Sciuto, S. A.; Scorza, A.

    2012-10-01

    The aim of the present study is to develop and compare two different automatic methods for accuracy evaluation in ultrasound phantom measurements on B-mode images: both of them give as a result the relative error e between measured distances, performed by 14 brand new ultrasound medical scanners, and nominal distances, among nylon wires embedded in a reference test object. The first method is based on a least squares estimation, while the second one applies the mean value of the same distance evaluated at different locations in ultrasound image (same distance method). Results for both of them are proposed and explained.

  14. Reflux esophagitis revisited: Prospective analysis of radiologic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Ott, D.J.; Gelfand, D.W.; Wu, W.C.

    1981-01-15

    A prospective radiologic-endoscopic study of the esophagogastric region in 266 patients, including 206 normals and 60 with esophagitis, is reported. The endoscopic classification grading severity of esophagitis was grade 1-normal; grades 2. 3. and 4-mild, moderate, and severe esophagitis, respectively. Radiology detected 22% of patient with mild esophagitis, 83% with moderate esophagitis, and 95% with severe esophagitis. Although hiatal hernia was present in 40% of normals and 89% with esophagitis, absence of radiographic hiatal hernia excluded esophagitis with 95% accuracy. The implications of this study regarding the role of radiology in evaluating patient with suspected reflux esophagitis are discussed.

  15. Classification Accuracy of Neural Networks with PCA in Emotion Recognition

    Directory of Open Access Journals (Sweden)

    Novakovic Jasmina

    2011-04-01

    Full Text Available This paper presents classification accuracy of neural network with principal component analysis (PCA for feature selections in emotion recognition using facial expressions. Dimensionality reduction of a feature set is a common preprocessing step used for pattern recognition and classification applications. PCA is one of the popular methods used, and can be shown to be optimal using different optimality criteria. Experiment results, in which we achieved a recognition rate of approximately 85% when testing six emotions on benchmark image data set, show that neural networks with PCA is effective in emotion recognition using facial expressions.

  16. Visual Inspection Displays Good Accuracy for Detecting Caries Lesions

    DEFF Research Database (Denmark)

    Twetman, Svante

    2015-01-01

    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....../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...

  17. Ionospheric Mapping Software Ensures Accuracy of Pilots GPS

    Science.gov (United States)

    2015-01-01

    IonoSTAGE and SuperTruth software are part of a suite created at the Jet Propulsion Laboratory to enable the Federal Aviation Administration's Wide Area Augmentation System, which provides pinpoint accuracy in aircraft GPS units. The system, used by more than 73,000 planes, facilitates landings under adverse conditions at small airports. In 2013, IonoSTAGE and SuperTruth found their first commercial license when NEC, based in Japan, with US headquarters in Irving, Texas, licensed the entire suite.

  18. High Accuracy Thermal Expansion Measurement at Cryogenic Temperatures

    Science.gov (United States)

    Tucker, Jim; Despit, Gregory; Stallcup, Michael; Presson, Joan; Nein, Max

    2003-01-01

    A new, interferometer-based system for measuring thermal expansion to an absolute accuracy of 20 ppb or better at cryogenic temperatures has been developed. Data from NIST Copper SRM 736 measured from room temperature to 15 K will be presented along with data from many other materials including beryllium, ULE, Zerodur, and composite materials. Particular attention will be given to a study by the Space Optics Manufacturing Technology Center (SOMTC) investigating the variability of ULE and beryllium materials used in the AMSD program Approximately 20 samples of each material, tested from room temperature to below 30 K are compared as a function of billet location.

  19. Metric Accuracy Evaluation of Dense Matching Algorithms in Archeological Applications

    Directory of Open Access Journals (Sweden)

    C. Re

    2011-12-01

    Full Text Available In the cultural heritage field the recording and documentation of small and medium size objects with very detailed Digital Surface Models (DSM is readily possible by through the use of high resolution and high precision triangulation laser scanners. 3D surface recording of archaeological objects can be easily achieved in museums; however, this type of record can be quite expensive. In many cases photogrammetry can provide a viable alternative for the generation of DSMs. The photogrammetric procedure has some benefits with respect to laser survey. The research described in this paper sets out to verify the reconstruction accuracy of DSMs of some archaeological artifacts obtained by photogrammetric survey. The experimentation has been carried out on some objects preserved in the Petrie Museum of Egyptian Archaeology at University College London (UCL. DSMs produced by two photogrammetric software packages are compared with the digital 3D model obtained by a state of the art triangulation color laser scanner. Intercomparison between the generated DSM has allowed an evaluation of metric accuracy of the photogrammetric approach applied to archaeological documentation and of precision performances of the two software packages.

  20. Photogrammetric methods applied to Svalbard glaciers: accuracies and challenges

    Directory of Open Access Journals (Sweden)

    Trond Eiken

    2012-06-01

    Full Text Available Use of digital images is expanding as a tool for glacier monitoring, and small-format time-lapse cameras are increasingly being used for glacier monitoring of fast-flowing glaciers. Stereoscopic imagery is preferable since it yields direct displacement results but stereo photogrammetry has more requirements regarding geometry in set-up and control points, as well as the additional cost of another complete camera system. We investigate a combination of methods to achieve satisfactory control of accuracy with resulting significant day-to-day velocity variations ranging from 1.5–4 m day−1 made at a distance of 2 km. Validation of results was made by comparing different methods, partly using the same image material, but also in combination with aerial and satellite images. Monoscopic results can also be used to gain continuity in a stereo data set when geometry or visibility is poor. We also explore the use of ordinary photographs taken from airliners for compilation of orthoimages as a potential low cost method for detection of sudden changes. The method, showing some tens of metres accuracy, was verified for monitoring velocities and front positions during a glacier surge and was also used to validate monoscopic time-lapse images.

  1. An analytically linearized helicopter model with improved modeling accuracy

    Science.gov (United States)

    Jensen, Patrick T.; Curtiss, H. C., Jr.; Mckillip, Robert M., Jr.

    1991-01-01

    An analytically linearized model for helicopter flight response including rotor blade dynamics and dynamic inflow, that was recently developed, was studied with the objective of increasing the understanding, the ease of use, and the accuracy of the model. The mathematical model is described along with a description of the UH-60A Black Hawk helicopter and flight test used to validate the model. To aid in utilization of the model for sensitivity analysis, a new, faster, and more efficient implementation of the model was developed. It is shown that several errors in the mathematical modeling of the system caused a reduction in accuracy. These errors in rotor force resolution, trim force and moment calculation, and rotor inertia terms were corrected along with improvements to the programming style and documentation. Use of a trim input file to drive the model is examined. Trim file errors in blade twist, control input phase angle, coning and lag angles, main and tail rotor pitch, and uniform induced velocity, were corrected. Finally, through direct comparison of the original and corrected model responses to flight test data, the effect of the corrections on overall model output is shown.

  2. High-accuracy mass spectrometry for fundamental studies.

    Science.gov (United States)

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  3. Accuracy improvement of geometric correction for CHRIS data

    Institute of Scientific and Technical Information of China (English)

    WANG Dian-zhong; PANG Yong; GUO Zhi-feng

    2008-01-01

    This paper deals with a new type of multi-angle remotely sensed data---CHRIS (the Compact High Resolution Imaging Spectrometer), by using rational function models (RFM) and rigorous sensor models (RSM). For ortho-rectifying an image set, a rigorous sensor model-Toutin's model was employed and a set of reported parameters including across track angle, along track angle, IFOV, altitude, period, eccentricity and orbit inclination were input, then, the orbit calculation was started and the track information was given to the raw data. The images were ortho-rectified with geocoded ASTER images and digital elevation (DEM) data. Results showed that with 16 ground control points (GCPs), the correction accuracy decreased with view zenith angle, and the RMSE value increased to be over one pixel at 36 degree off-nadir. When the GCPs were approximately chosen as in Toutin's model, a RFM with three coefficients produced the same accuracy trend versus view zenith angle while the RMSEs for all angles were improved and within about one pixel.

  4. Required accuracy and dose thresholds in individual monitoring

    DEFF Research Database (Denmark)

    Christensen, P.; Griffith, R.V.

    1994-01-01

    The paper follows the approach given in recent revisions of CEC and IAEA recommendations on requirements in individual monitoring for external radiations. The ICRP requirements on overall accuracy for individual monitoring, as given in ICRP Publication 35 (1982), form the basis for the specificat......The paper follows the approach given in recent revisions of CEC and IAEA recommendations on requirements in individual monitoring for external radiations. The ICRP requirements on overall accuracy for individual monitoring, as given in ICRP Publication 35 (1982), form the basis...... this uncertainty factor, a value of 21% can be evaluated for the allowable maximum overall standard deviation for dose measurements at dose levels near the annual dose limits increasing to 45% for dose levels at the lower end of the dose range required to be monitored. A method is described for evaluating...... the overall standard deviation of the dosimetry system by combining random and systematic uncertainties in quadrature, and procedures are also given for determining each individual uncertainty connected to the dose measurement. In particular, attention is paid to the evaluation of the combined uncertainty due...

  5. The diagnostic accuracy of MR imaging in osteoid osteoma

    Energy Technology Data Exchange (ETDEWEB)

    Davies, Mark; Cassar-Pullicino, Victor N.; McCall, Iain W.; Tyrrell, Prudencia N.M. [Department of Radiology, The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG (United Kingdom); Davies, Mark A. [The MRI Centre, Royal Orthopaedic Hospital, Birmingham (United Kingdom)

    2002-10-01

    To analyse the MR imaging appearances of a large series of osteoid osteomas, to assess the ability of MR imaging to detect the tumour, and to identify potential reasons for misdiagnosis.Design and patients. The MR imaging findings of 43 patients with osteoid osteoma were reviewed retrospectively and then compared with other imaging modalities to assess the accuracy of MR localisation and interpretation.Results. The potential for a missed diagnosis was 35% based solely on the MR investigations. This included six tumours which were not seen and nine which were poorly visualised. The major determinants of the diagnostic accuracy of MR imaging were the MR technique, skeletal location, and preliminary radiographic appearances. There was a wide spectrum of MR signal appearances of the lesion. The tumour was identified in 65% of sequences performed in the axial plane. The nidus was present in only one slice of the optimal sequence in 27 patients. Reactive bone changes were present in 33 and soft tissue changes in 37 patients.Conclusion. Reliance on MR imaging alone may lead to misdiagnosis. As the osteoid osteoma may be difficult to identify and the MR features easily misinterpreted, optimisation of MR technique is crucial in reducing the risk of missing the diagnosis. Unexplained areas of bone marrow oedema in particular require further imaging (scintigraphy and CT) to exclude an osteoid osteoma. (orig.)

  6. Influence of chamber misalignment on cased telescoped (CT) ammunition accuracy

    Institute of Scientific and Technical Information of China (English)

    D. CORRIVEAU; C. FLORIN PETRE

    2016-01-01

    As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT) ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

  7. Cadastral Positioning Accuracy Improvement: a Case Study in Malaysia

    Science.gov (United States)

    Hashim, N. M.; Omar, A. H.; Omar, K. M.; Abdullah, N. M.; Yatim, M. H. M.

    2016-09-01

    Cadastral map is a parcel-based information which is specifically designed to define the limitation of boundaries. In Malaysia, the cadastral map is under authority of the Department of Surveying and Mapping Malaysia (DSMM). With the growth of spatial based technology especially Geographical Information System (GIS), DSMM decided to modernize and reform its cadastral legacy datasets by generating an accurate digital based representation of cadastral parcels. These legacy databases usually are derived from paper parcel maps known as certified plan. The cadastral modernization will result in the new cadastral database no longer being based on single and static parcel paper maps, but on a global digital map. Despite the strict process of the cadastral modernization, this reform has raised unexpected queries that remain essential to be addressed. The main focus of this study is to review the issues that have been generated by this transition. The transformed cadastral database should be additionally treated to minimize inherent errors and to fit them to the new satellite based coordinate system with high positional accuracy. This review result will be applied as a foundation for investigation to study the systematic and effectiveness method for Positional Accuracy Improvement (PAI) in cadastral database modernization.

  8. Accuracy of marker-assisted selection with auxiliary traits

    Indian Academy of Sciences (India)

    P Narain

    2003-09-01

    Genetic information on molecular markers is increasingly being used in plant and animal improvement programmes particularly as indirect means to improve a metric trait by selection either on an individual basis or on the basis of an index incorporating such information. This paper examines the utility of an index of selection that not only combines phenotypic and molecular information on the trait under improvement but also combines similar information on one or more auxiliary traits. The accuracy of such a selection procedure has been theoretically studied for sufficiently large populations so that the effects of detected quantitative trait loci can be perfectly estimated. The theory is illustrated numerically by considering one auxiliary trait. It is shown that the use of an auxiliary trait improves the selection accuracy; and, hence, the relative efficiency of index selection compared to individual selection which is based on the same intensity of selection. This is particularly so for higher magnitudes of residual genetic correlation and environmental correlation having opposite signs, lower values of the proportion of genetic variation in the main trait associated with the markers, negligible proportion of genetic variation in the auxiliary trait associated with the markers, and lower values of the heritability of the main trait but higher values of the heritability of the auxiliary trait.

  9. Modeling Linkage Disequilibrium Increases Accuracy of Polygenic Risk Scores

    Science.gov (United States)

    Vilhjálmsson, Bjarni J.; Yang, Jian; Finucane, Hilary K.; Gusev, Alexander; Lindström, Sara; Ripke, Stephan; Genovese, Giulio; Loh, Po-Ru; Bhatia, Gaurav; Do, Ron; Hayeck, Tristan; Won, Hong-Hee; Ripke, Stephan; Neale, Benjamin M.; Corvin, Aiden; Walters, James T.R.; Farh, Kai-How; Holmans, Peter A.; Lee, Phil; Bulik-Sullivan, Brendan; Collier, David A.; Huang, Hailiang; Pers, Tune H.; Agartz, Ingrid; Agerbo, Esben; Albus, Margot; Alexander, Madeline; Amin, Farooq; Bacanu, Silviu A.; Begemann, Martin; Belliveau, Richard A.; Bene, Judit; Bergen, Sarah E.; Bevilacqua, Elizabeth; Bigdeli, Tim B.; Black, Donald W.; Bruggeman, Richard; Buccola, Nancy G.; Buckner, Randy L.; Byerley, William; Cahn, Wiepke; Cai, Guiqing; Campion, Dominique; Cantor, Rita M.; Carr, Vaughan J.; Carrera, Noa; Catts, Stanley V.; Chambert, Kimberly D.; Chan, Raymond C.K.; Chen, Ronald Y.L.; Chen, Eric Y.H.; Cheng, Wei; Cheung, Eric F.C.; Chong, Siow Ann; Cloninger, C. Robert; Cohen, David; Cohen, Nadine; Cormican, Paul; Craddock, Nick; Crowley, James J.; Curtis, David; Davidson, Michael; Davis, Kenneth L.; Degenhardt, Franziska; Del Favero, Jurgen; DeLisi, Lynn E.; Demontis, Ditte; Dikeos, Dimitris; Dinan, Timothy; Djurovic, Srdjan; Donohoe, Gary; Drapeau, Elodie; Duan, Jubao; Dudbridge, Frank; Durmishi, Naser; Eichhammer, Peter; Eriksson, Johan; Escott-Price, Valentina; Essioux, Laurent; Fanous, Ayman H.; Farrell, Martilias S.; Frank, Josef; Franke, Lude; Freedman, Robert; Freimer, Nelson B.; Friedl, Marion; Friedman, Joseph I.; Fromer, Menachem; Genovese, Giulio; Georgieva, Lyudmila; Gershon, Elliot S.; Giegling, Ina; Giusti-Rodrguez, Paola; Godard, Stephanie; Goldstein, Jacqueline I.; Golimbet, Vera; Gopal, Srihari; Gratten, Jacob; Grove, Jakob; de Haan, Lieuwe; Hammer, Christian; Hamshere, Marian L.; Hansen, Mark; Hansen, Thomas; Haroutunian, Vahram; Hartmann, Annette M.; Henskens, Frans A.; Herms, Stefan; Hirschhorn, Joel N.; Hoffmann, Per; Hofman, Andrea; Hollegaard, Mads V.; Hougaard, David M.; Ikeda, Masashi; Joa, Inge; Julia, Antonio; Kahn, Rene S.; Kalaydjieva, Luba; Karachanak-Yankova, Sena; Karjalainen, Juha; Kavanagh, David; Keller, Matthew C.; Kelly, Brian J.; Kennedy, James L.; Khrunin, Andrey; Kim, Yunjung; Klovins, Janis; Knowles, James A.; Konte, Bettina; Kucinskas, Vaidutis; Kucinskiene, Zita Ausrele; Kuzelova-Ptackova, Hana; Kahler, Anna K.; Laurent, Claudine; Keong, Jimmy Lee Chee; Lee, S. Hong; Legge, Sophie E.; Lerer, Bernard; Li, Miaoxin; Li, Tao; Liang, Kung-Yee; Lieberman, Jeffrey; Limborska, Svetlana; Loughland, Carmel M.; Lubinski, Jan; Lnnqvist, Jouko; Macek, Milan; Magnusson, Patrik K.E.; Maher, Brion S.; Maier, Wolfgang; Mallet, Jacques; Marsal, Sara; Mattheisen, Manuel; Mattingsdal, Morten; McCarley, Robert W.; McDonald, Colm; McIntosh, Andrew M.; Meier, Sandra; Meijer, Carin J.; Melegh, Bela; Melle, Ingrid; Mesholam-Gately, Raquelle I.; Metspalu, Andres; Michie, Patricia T.; Milani, Lili; Milanova, Vihra; Mokrab, Younes; Morris, Derek W.; Mors, Ole; Mortensen, Preben B.; Murphy, Kieran C.; Murray, Robin M.; Myin-Germeys, Inez; Mller-Myhsok, Bertram; Nelis, Mari; Nenadic, Igor; Nertney, Deborah A.; Nestadt, Gerald; Nicodemus, Kristin K.; Nikitina-Zake, Liene; Nisenbaum, Laura; Nordin, Annelie; O’Callaghan, Eadbhard; O’Dushlaine, Colm; O’Neill, F. Anthony; Oh, Sang-Yun; Olincy, Ann; Olsen, Line; Van Os, Jim; Pantelis, Christos; Papadimitriou, George N.; Papiol, Sergi; Parkhomenko, Elena; Pato, Michele T.; Paunio, Tiina; Pejovic-Milovancevic, Milica; Perkins, Diana O.; Pietilinen, Olli; Pimm, Jonathan; Pocklington, Andrew J.; Powell, John; Price, Alkes; Pulver, Ann E.; Purcell, Shaun M.; Quested, Digby; Rasmussen, Henrik B.; Reichenberg, Abraham; Reimers, Mark A.; Richards, Alexander L.; Roffman, Joshua L.; Roussos, Panos; Ruderfer, Douglas M.; Salomaa, Veikko; Sanders, Alan R.; Schall, Ulrich; Schubert, Christian R.; Schulze, Thomas G.; Schwab, Sibylle G.; Scolnick, Edward M.; Scott, Rodney J.; Seidman, Larry J.; Shi, Jianxin; Sigurdsson, Engilbert; Silagadze, Teimuraz; Silverman, Jeremy M.; Sim, Kang; Slominsky, Petr; Smoller, Jordan W.; So, Hon-Cheong; Spencer, Chris C.A.; Stahl, Eli A.; Stefansson, Hreinn; Steinberg, Stacy; Stogmann, Elisabeth; Straub, Richard E.; Strengman, Eric; Strohmaier, Jana; Stroup, T. Scott; Subramaniam, Mythily; Suvisaari, Jaana; Svrakic, Dragan M.; Szatkiewicz, Jin P.; Sderman, Erik; Thirumalai, Srinivas; Toncheva, Draga; Tooney, Paul A.; Tosato, Sarah; Veijola, Juha; Waddington, John; Walsh, Dermot; Wang, Dai; Wang, Qiang; Webb, Bradley T.; Weiser, Mark; Wildenauer, Dieter B.; Williams, Nigel M.; Williams, Stephanie; Witt, Stephanie H.; Wolen, Aaron R.; Wong, Emily H.M.; Wormley, Brandon K.; Wu, Jing Qin; Xi, Hualin Simon; Zai, Clement C.; Zheng, Xuebin; Zimprich, Fritz; Wray, Naomi R.; Stefansson, Kari; Visscher, Peter M.; Adolfsson, Rolf; Andreassen, Ole A.; Blackwood, Douglas H.R.; Bramon, Elvira; Buxbaum, Joseph D.; Børglum, Anders D.; Cichon, Sven; Darvasi, Ariel; Domenici, Enrico; Ehrenreich, Hannelore; Esko, Tonu; Gejman, Pablo V.; Gill, Michael; Gurling, Hugh; Hultman, Christina M.; Iwata, Nakao; Jablensky, Assen V.; Jonsson, Erik G.; Kendler, Kenneth S.; Kirov, George; Knight, Jo; Lencz, Todd; Levinson, Douglas F.; Li, Qingqin S.; Liu, Jianjun; Malhotra, Anil K.; McCarroll, Steven A.; McQuillin, Andrew; Moran, Jennifer L.; Mortensen, Preben B.; Mowry, Bryan J.; Nthen, Markus M.; Ophoff, Roel A.; Owen, Michael J.; Palotie, Aarno; Pato, Carlos N.; Petryshen, Tracey L.; Posthuma, Danielle; Rietschel, Marcella; Riley, Brien P.; Rujescu, Dan; Sham, Pak C.; Sklar, Pamela; St. Clair, David; Weinberger, Daniel R.; Wendland, Jens R.; Werge, Thomas; Daly, Mark J.; Sullivan, Patrick F.; O’Donovan, Michael C.; Kraft, Peter; Hunter, David J.; Adank, Muriel; Ahsan, Habibul; Aittomäki, Kristiina; Baglietto, Laura; Berndt, Sonja; Blomquist, Carl; Canzian, Federico; Chang-Claude, Jenny; Chanock, Stephen J.; Crisponi, Laura; Czene, Kamila; Dahmen, Norbert; Silva, Isabel dos Santos; Easton, Douglas; Eliassen, A. Heather; Figueroa, Jonine; Fletcher, Olivia; Garcia-Closas, Montserrat; Gaudet, Mia M.; Gibson, Lorna; Haiman, Christopher A.; Hall, Per; Hazra, Aditi; Hein, Rebecca; Henderson, Brian E.; Hofman, Albert; Hopper, John L.; Irwanto, Astrid; Johansson, Mattias; Kaaks, Rudolf; Kibriya, Muhammad G.; Lichtner, Peter; Lindström, Sara; Liu, Jianjun; Lund, Eiliv; Makalic, Enes; Meindl, Alfons; Meijers-Heijboer, Hanne; Müller-Myhsok, Bertram; Muranen, Taru A.; Nevanlinna, Heli; Peeters, Petra H.; Peto, Julian; Prentice, Ross L.; Rahman, Nazneen; Sánchez, María José; Schmidt, Daniel F.; Schmutzler, Rita K.; Southey, Melissa C.; Tamimi, Rulla; Travis, Ruth; Turnbull, Clare; Uitterlinden, Andre G.; van der Luijt, Rob B.; Waisfisz, Quinten; Wang, Zhaoming; Whittemore, Alice S.; Yang, Rose; Zheng, Wei; Kathiresan, Sekar; Pato, Michele; Pato, Carlos; Tamimi, Rulla; Stahl, Eli; Zaitlen, Noah; Pasaniuc, Bogdan; Belbin, Gillian; Kenny, Eimear E.; Schierup, Mikkel H.; De Jager, Philip; Patsopoulos, Nikolaos A.; McCarroll, Steve; Daly, Mark; Purcell, Shaun; Chasman, Daniel; Neale, Benjamin; Goddard, Michael; Visscher, Peter M.; Kraft, Peter; Patterson, Nick; Price, Alkes L.

    2015-01-01

    Polygenic risk scores have shown great promise in predicting complex disease risk and will become more accurate as training sample sizes increase. The standard approach for calculating risk scores involves linkage disequilibrium (LD)-based marker pruning and applying a p value threshold to association statistics, but this discards information and can reduce predictive accuracy. We introduce LDpred, a method that infers the posterior mean effect size of each marker by using a prior on effect sizes and LD information from an external reference panel. Theory and simulations show that LDpred outperforms the approach of pruning followed by thresholding, particularly at large sample sizes. Accordingly, predicted R2 increased from 20.1% to 25.3% in a large schizophrenia dataset and from 9.8% to 12.0% in a large multiple sclerosis dataset. A similar relative improvement in accuracy was observed for three additional large disease datasets and for non-European schizophrenia samples. The advantage of LDpred over existing methods will grow as sample sizes increase. PMID:26430803

  10. Accuracy of distal radius positioning using an anatomical plate.

    Science.gov (United States)

    Vroemen, Joy C; Dobbe, Johannes G G; Sierevelt, Inger N; Strackee, Simon D; Streekstra, Geert J

    2013-04-01

    Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii. The authors simulated a defect by removing an arbitrary wedge shape from the artificial radii. Two surgeons corrected these fractures by placing 2 anatomical plate types according to the plate manufacturers' instructions. The residual positioning errors of the distal segment in relation to the unaffected radii were determined using 3-dimensional imaging and were compared with naturally occurring bilateral radius differences in healthy individuals. In many cases, positioning does not agree with differences based on bilateral asymmetry in healthy patients.This study indicated the accuracy of anatomical plates. Positioning an anatomical plate may lead to considerable residual errors in individual patients. Volar distal radius plate shapes differ among plate manufacturers. Therefore, one plate may perform better than another in an individual.

  11. Evaluation of DEM generation accuracy from UAS imagery

    Science.gov (United States)

    Santise, M.; Fornari, M.; Forlani, G.; Roncella, R.

    2014-06-01

    The growing use of UAS platform for aerial photogrammetry comes with a new family of Computer Vision highly automated processing software expressly built to manage the peculiar characteristics of these blocks of images. It is of interest to photogrammetrist and professionals, therefore, to find out whether the image orientation and DSM generation methods implemented in such software are reliable and the DSMs and orthophotos are accurate. On a more general basis, it is interesting to figure out whether it is still worth applying the standard rules of aerial photogrammetry to the case of drones, achieving the same inner strength and the same accuracies as well. With such goals in mind, a test area has been set up at the University Campus in Parma. A large number of ground points has been measured on natural as well as signalized points, to provide a comprehensive test field, to check the accuracy performance of different UAS systems. In the test area, points both at ground-level and features on the buildings roofs were measured, in order to obtain a distributed support also altimetrically. Control points were set on different types of surfaces (buildings, asphalt, target, fields of grass and bumps); break lines, were also employed. The paper presents the results of a comparison between two different surveys for DEM (Digital Elevation Model) generation, performed at 70 m and 140 m flying height, using a Falcon 8 UAS.

  12. Accuracy of Posterior Subtalar Joint Injection Without Fluoroscopy

    Science.gov (United States)

    Kirk, Kevin L.; Campbell, John T.; Guyton, Gregory P.

    2008-01-01

    Injection into the posterior subtalar joint has not been validated for accuracy using radiographic end points. We asked whether needle placement into a normal posterior subtalar joint could be performed accurately and selectively by experienced surgeons without fluoroscopic guidance. Three fellowship-trained orthopaedic foot and ankle surgeons each injected the posterior subtalar joint of 20 cadaveric specimens using an anterolateral approach. Fluoroscopic images were obtained by an independent investigator and blinded. A separate fellowship-trained foot and ankle surgeon interpreted the images. Of 60 injections, 58 were accurate and two were extraarticular based on interpretation by an independent foot and ankle surgeon. Extravasation into the ankle occurred in 14 samples and into the peroneal sheath in two samples. Experienced surgeons can place intraarticular injections into a radiographically normal posterior subtalar joint without fluoroscopy with a high degree of accuracy. However, extravasation into the ankle or peroneal tendon sheath occurred in an unpredictable fashion, suggesting selectivity of injection placement is relatively limited without the use of fluoroscopy. Fluoroscopy may not be necessary for injections used solely for therapeutic purposes. However, if the injection is intended for diagnostic purposes or to assist in surgical decision-making or if the joint is abnormal, we recommend fluoroscopy to ensure the subtalar joint is the only anatomic structure impacted by the injection. PMID:18404293

  13. On the accuracy of close stellar approaches determination

    CERN Document Server

    Dybczyński, Piotr A

    2015-01-01

    The aim of this paper is to demonstrate the accuracy of our knowledge of close stellar passage distances in the pre-GAIA era.We used the most precise astrometric and kinematic data available at the moment and prepared a list of 40 stars nominally passing (in the past or future) closer than 2 pc from the Sun.We used a full gravitational potential of the Galaxy to calculate the motion of the Sun and a star from their current positions to the proximity epoch. For this calculations we used a numerical integration in rectangular, Galactocentric coordinates. We showed that in many cases the numerical integration of the star motion gives significantly different results than popular rectilinear approximation.We found several new stellar candidates for close visitors in past or in future. We used a covariance matrices of the astrometric data for each star to estimate the accuracy of the obtained proximity distance and epoch. To this aim we used a Monte Carlo method, replaced each star with 10 000 of its clones and stu...

  14. CADASTRAL POSITIONING ACCURACY IMPROVEMENT: A CASE STUDY IN MALAYSIA

    Directory of Open Access Journals (Sweden)

    N. M. Hashim

    2016-09-01

    Full Text Available Cadastral map is a parcel-based information which is specifically designed to define the limitation of boundaries. In Malaysia, the cadastral map is under authority of the Department of Surveying and Mapping Malaysia (DSMM. With the growth of spatial based technology especially Geographical Information System (GIS, DSMM decided to modernize and reform its cadastral legacy datasets by generating an accurate digital based representation of cadastral parcels. These legacy databases usually are derived from paper parcel maps known as certified plan. The cadastral modernization will result in the new cadastral database no longer being based on single and static parcel paper maps, but on a global digital map. Despite the strict process of the cadastral modernization, this reform has raised unexpected queries that remain essential to be addressed. The main focus of this study is to review the issues that have been generated by this transition. The transformed cadastral database should be additionally treated to minimize inherent errors and to fit them to the new satellite based coordinate system with high positional accuracy. This review result will be applied as a foundation for investigation to study the systematic and effectiveness method for Positional Accuracy Improvement (PAI in cadastral database modernization.

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

    Science.gov (United States)

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

    2016-09-01

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

  16. Concerning accuracy of determination of reflecting power of coals

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, A.E.

    1986-02-01

    In the Kuzbass work was conducted recently to refine accuracy of measurement of index of reflecting power of coals of all ranks. Reflecting power of 300 samples of coals was measured in conformity with the All Union State Standard (AUSS) on MIM-7 apparatus and worked up using an electronic computer. From a comparison of factual (absolute) errors obtained by experiment with errors calculated according to AUSS, differences in results make clear a more differentiated scale for evaluating accuracy of measurement of index of reflecting power than the AUSS linear scale is needed. According to experimental facts, errors in measurement of reflecting power are nonlinear. A table compares errors in reflecting power measured in several laboratories with errors determined according to AUSS showing that errors according to AUSS are greater than experimental ones. Therefore, considering the nonlinear character of change of error of measurements of reflecting power, the scale of errors must be more differentiated than the linear scale used by AUSS 12113-77 and magnitudes of error are smaller than those determined by AUSS.

  17. Spatial Accuracy Assessment and Integration of Global Land Cover Datasets

    Directory of Open Access Journals (Sweden)

    Nandin-Erdene Tsendbazar

    2015-11-01

    Full Text Available Along with the creation of new maps, current efforts for improving global land cover (GLC maps focus on integrating maps by accounting for their relative merits, e.g., agreement amongst maps or map accuracy. Such integration efforts may benefit from the use of multiple GLC reference datasets. Using available reference datasets, this study assesses spatial accuracy of recent GLC maps and compares methods for creating an improved land cover (LC map. Spatial correspondence with reference dataset was modeled for Globcover-2009, Land Cover-CCI-2010, MODIS-2010 and Globeland30 maps for Africa. Using different scenarios concerning the used input data, five integration methods for an improved LC map were tested and cross-validated. Comparison of the spatial correspondences showed that the preferences for GLC maps varied spatially. Integration methods using both the GLC maps and reference data at their locations resulted in 4.5%–13% higher correspondence with the reference LC than any of the input GLC maps. An integrated LC map and LC class probability maps were computed using regression kriging, which produced the highest correspondence (76%. Our results demonstrate the added value of using reference datasets and geostatistics for improving GLC maps. This approach is useful as more GLC reference datasets are becoming publicly available and their reuse is being encouraged.

  18. Accuracy of references in Internet Journal of Medical Update

    Directory of Open Access Journals (Sweden)

    Prakash Adhikari

    2011-07-01

    Full Text Available This study was done to observe the accuracy of references in articles published in Internet Journal of Medical Update (IJMU. Sixty references were randomly selected from IJMU (Volume 5, Number 2, July 2010, Volume 4, Number 2, July 2009 and Volume 4, Number 1, January 2009. The instructions for authors of this journal were looked carefully. All the references were compared with the original for accuracy, using the following six elements: authors name; journal name as per Index Medicus; year; volume; and page numbers. References were considered incorrect if there was an error in any of these six elements. Statistical analysis was done by using frequency and percentage. Ten percent references in Internet Journal of Medical Update were inaccurate. Most common errors were author’s name and title of the article. Author’s names were found to be incorrect in 5.0% references while title of the article was found to be incorrect in 3.3%. Least common error was found in writing the journal name (either incorrect abbreviations or incorrect instructions or punctuation errors in (1.7%. Inaccuracies of references are also found in the Internet Journal of Medical Update. The majority of errors in IJMU are avoidable. So, the authors, editors and the reviewers have to check for any errors seriously before publication in the journal.

  19. MDCT arthrography of the wrist: Diagnostic accuracy and indications

    Energy Technology Data Exchange (ETDEWEB)

    De Filippo, Massimo [Department of Clinical Sciences, Section of Radiological Sciences, University of Parma, Parma Hospital, Via Gramsci, 14, 43100 Parma (Italy)], E-mail: massimo.defilippo@unipr.it; Pogliacomi, Francesco [Orthopaedics, Traumatology and Functional Rehabilitation Unit, Department of Surgical Sciences, University of Parma, Parma Hospital, Via Gramsci 14, 43100 Parma (Italy); Bertellini, Annalisa [Department of Clinical Sciences, Section of Radiological Sciences, University of Parma, Parma Hospital, Via Gramsci, 14, 43100 Parma (Italy); Araoz, Philip A. [Department of Radiology, Division of Biostatistics, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (United States); Averna, Raffaele; Sverzellati, Nicola; Ingegnoli, Anna [Department of Clinical Sciences, Section of Radiological Sciences, University of Parma, Parma Hospital, Via Gramsci, 14, 43100 Parma (Italy); Corradi, Maurizio; Costantino, Cosimo [Orthopaedics, Traumatology and Functional Rehabilitation Unit, Department of Surgical Sciences, University of Parma, Parma Hospital, Via Gramsci 14, 43100 Parma (Italy); Zompatori, Maurizio [Department of Radiological and Histopathological Sciences, Policlinic S.Orsola-Malpighi, University of Bologna, Via Massarenti 9, 40138 Bologna (Italy)

    2010-04-15

    Purpose: To evaluate the diagnostic accuracy and indications of arthrography with Multidetector Computed Tomography (arthro-MDCT) of the wrist in patients with absolute or relative contraindications to magnetic resonance imaging (MRI) studies and in patients with periarticular metal implants using diagnostic arthroscopy as the gold standard. Materials and methods: After intra-articular injection of iodixanol and volumetric acquisition, 43 wrists in patients of both genders (18 females, 25 males, age range 32-60 years) were examined with a 16-detector-row CT scanner. Fifteen patients had prior wrist surgery. The patients had arthralgia, degenerative and traumatic arthropathies as well as limited range of motion, but no radiologically detected fractures. All examinations were interpreted by two experienced musculoskeletal radiologists. The findings were compared with arthroscopic findings carried out within 28 days of the CT study. Results: In non-operated and operated wrists the comparison between arthro-MDCT and arthroscopy showed sensitivity, specificity and accuracy ranging between 92% and 94% for triangular fibrocartilage complex (TFCC), between 80% and 100% for intrinsic ligaments located within the proximal carpal compartment, and between 94% and 100% for articular cartilage. Inter-observer agreement between two radiologists, in the evaluation of all types of lesions, was almost perfect (k = 0.96) and statistically significant (p < 0.05). Conclusions: Arthro-MDCT of the wrist provides an accurate diagnosis to identify chondral, fibrocartilaginous and intra-articular ligament lesions in patients who cannot be evaluated by MRI, and in post-surgical patients.

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

    Science.gov (United States)

    Vojdani, Mahroo; Torabi, Kianoosh; Ansarifard, Elham

    2015-01-01

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

  1. Kinematic GPS survey as validation of LIDAR strips accuracy

    Directory of Open Access Journals (Sweden)

    C. Gordini

    2006-06-01

    Full Text Available As a result of the catastrophic hydrogeological events which occurred in May 1998 in Campania, in the south of Italy, the distinctive features of airborne laser scanning mounted on a helicopter were used to survey the landslides at Sarno and Quindici. In order to survey the entire zone of interest, approximately 21 km2, it was necessary to scan 12 laser strips. Many problems arose during the survey: difficulties in receiving the GPS signal, complex terrain features and unfavorable atmospheric conditions. These problems were investigated and it emerged that one of the most influential factors is the quality of GPS signals. By analysing the original GPS data, the traces obtained by fixing phase ambiguity with an On The Fly (OTF algorithm were isolated from those with smoothed differential GPS solution (DGPS. Processing and analysis of laser data showed that not all the overlapping laser strips were congruent with each other. Since an external survey to verify the laser data accuracy was necessary, it was decided to utilize the kinematic GPS technique. The laser strips were subsequently adjusted, using the kinematic GPS data as reference points. Bearing in mind that in mountainous areas like the one studied here it is not possible to obtain nominal precision and accuracy, a good result was nevertheless obtained with a Digital Terrain Model (DTM of all the zones of interest.

  2. Accuracy Assessment of a Uav-Based Landslide Monitoring System

    Science.gov (United States)

    Peppa, M. V.; Mills, J. P.; Moore, P.; Miller, P. E.; Chambers, J. E.

    2016-06-01

    Landslides are hazardous events with often disastrous consequences. Monitoring landslides with observations of high spatio-temporal resolution can help mitigate such hazards. Mini unmanned aerial vehicles (UAVs) complemented by structure-from-motion (SfM) photogrammetry and modern per-pixel image matching algorithms can deliver a time-series of landslide elevation models in an automated and inexpensive way. This research investigates the potential of a mini UAV, equipped with a Panasonic Lumix DMC-LX5 compact camera, to provide surface deformations at acceptable levels of accuracy for landslide assessment. The study adopts a self-calibrating bundle adjustment-SfM pipeline using ground control points (GCPs). It evaluates misalignment biases and unresolved systematic errors that are transferred through the SfM process into the derived elevation models. To cross-validate the research outputs, results are compared to benchmark observations obtained by standard surveying techniques. The data is collected with 6 cm ground sample distance (GSD) and is shown to achieve planimetric and vertical accuracy of a few centimetres at independent check points (ICPs). The co-registration error of the generated elevation models is also examined in areas of stable terrain. Through this error assessment, the study estimates that the vertical sensitivity to real terrain change of the tested landslide is equal to 9 cm.

  3. ACCURACY ASSESSMENT OF A UAV-BASED LANDSLIDE MONITORING SYSTEM

    Directory of Open Access Journals (Sweden)

    M. V. Peppa

    2016-06-01

    Full Text Available Landslides are hazardous events with often disastrous consequences. Monitoring landslides with observations of high spatio-temporal resolution can help mitigate such hazards. Mini unmanned aerial vehicles (UAVs complemented by structure-from-motion (SfM photogrammetry and modern per-pixel image matching algorithms can deliver a time-series of landslide elevation models in an automated and inexpensive way. This research investigates the potential of a mini UAV, equipped with a Panasonic Lumix DMC-LX5 compact camera, to provide surface deformations at acceptable levels of accuracy for landslide assessment. The study adopts a self-calibrating bundle adjustment-SfM pipeline using ground control points (GCPs. It evaluates misalignment biases and unresolved systematic errors that are transferred through the SfM process into the derived elevation models. To cross-validate the research outputs, results are compared to benchmark observations obtained by standard surveying techniques. The data is collected with 6 cm ground sample distance (GSD and is shown to achieve planimetric and vertical accuracy of a few centimetres at independent check points (ICPs. The co-registration error of the generated elevation models is also examined in areas of stable terrain. Through this error assessment, the study estimates that the vertical sensitivity to real terrain change of the tested landslide is equal to 9 cm.

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

    Science.gov (United States)

    Tochizawa, Saiko; Shibata, Midori; Terasawa, Yuri

    2016-01-01

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

  5. Accuracy of digital impression in dental implants: A literature review

    Directory of Open Access Journals (Sweden)

    Sudabe Kulivand

    2016-12-01

    Full Text Available Restoration of dental implants remains one of the most challenging aspects of implant dentistry. Although it is not clear whether prosthetic misfit could affect osseointegration, mechanical complications of implant-supported prostheses can be avoided by achieving a good passive fit between the framework and the implants. Passive fit is a difficult concept to define. Obtaining absolute passive fit of the prosthetic framework on implants has been reported to be nearly impossible. Because of the multiple steps involved in processing and manufacturing implant-borne prostheses, errors in precision seem to be unavoidable. Misfit of prosthesis may lead to mechanical failures such as screw distortion and loosening, component fractures and even implant failure. Digital impressions offer advantages to both the clinician and the patient. For clinicians, digital impressions may reduce laboratory remakes because the computer screen image of the prepared teeth is magnified, improving the view of the preparation quality. The quality and accuracy of impressions has been demonstrated to be an effective clinical procedure for reducing inaccuracies in prostheses. So, the aim of the current research was to determine accuracy of digital impression in dental implants using the PubMed and Medline database English literature by the terms “Digital impression”, “Implants”, Dentistry”.

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

    Science.gov (United States)

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

    2017-01-01

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

  7. On the Accuracy Potential in Underwater/Multimedia Photogrammetry

    Directory of Open Access Journals (Sweden)

    Hans-Gerd Maas

    2015-07-01

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

  8. THE DIAGNOSTIC ACCURACY OF IMPRINT CYTOLOGY IN BREAST LESIONS

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    Shashidhar

    2015-03-01

    Full Text Available BACKGROUND : The imprint cytology is one of the rapid diagnostic tools in the field of diagnostic pathology. This method not only helps us to examine the individual cells but also aids in analyzing the patterns of particular lesion. Differentiating between benign and malignant lesions prior to or during surgery, helps the surgeon to decide on the extent of surgery. AIMS : The present study was conducted to know the accuracy of intraoperative imprint smears and to compare the results with that of histopathological sections in all breast tumors. MATERIALS AND METHOD S : This was a descriptive study on 100 cases of breast lesions comprising of inflammatory, benign & malignant. Results were compared with histopathology. STATISTICAL ANALYSIS USED: Sensitivity, specificity, positive predictive value an d negative predictive value . RESULTS : Out of 100 cases, 50 cases were diagnosed as benign and 50 cases as malignant lesions on imprint smear . Fibroadenoma (26% was the most common benign lesion and invasive ductal carcinoma ( 38% was the most common malig nant lesion. The sensitivity and specificity of imprint cytology were 98% and 96.1% respectively. 96% PPV, 98% NPV and 97% overall diagnostic accuracy was observed for imprint cytology in the present study. CONCLUSIONS: Imprint cytology is a simple, accurate, rapid & cost effective diagnostic tool used intra operatively, where in facilities for frozen sections are not available. KEYWORDS : Imprint; histopathology; benign ; malignant; breast.

  9. Registration accuracy and quality of real-life images.

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    Wei-Yen Hsu

    Full Text Available BACKGROUND: A common registration problem for the application of consumer device is to align all the acquired image sequences into a complete scene. Image alignment requires a registration algorithm that will compensate as much as possible for geometric variability among images. However, images captured views from a real scene usually produce different distortions. Some are derived from the optic characteristics of image sensors, and others are caused by the specific scenes and objects. METHODOLOGY/PRINCIPAL FINDINGS: An image registration algorithm considering the perspective projection is proposed for the application of consumer devices in this study. It exploits a multiresolution wavelet-based method to extract significant features. An analytic differential approach is then proposed to achieve fast convergence of point matching. Finally, the registration accuracy is further refined to obtain subpixel precision by a feature-based modified Levenberg-Marquardt method. Due to its feature-based and nonlinear characteristic, it converges considerably faster than most other methods. In addition, vignette compensation and color difference adjustment are also performed to further improve the quality of registration results. CONCLUSIONS/SIGNIFICANCE: The performance of the proposed method is evaluated by testing the synthetic and real images acquired by a hand-held digital still camera and in comparison with two registration techniques in terms of the squared sum of intensity differences (SSD and correlation coefficient (CC. The results indicate that the proposed method is promising in registration accuracy and quality, which are statistically significantly better than other two approaches.

  10. Evaluating the predictive accuracy of microloan officers’ subjective judgment

    Directory of Open Access Journals (Sweden)

    Ibtissem Baklouti

    2013-04-01

    Full Text Available The peculiarity in lending methodology in Microfinance institution characterized by unchallenged dominance of the loan officers in the decision-making prompted us to investigate the predictive accuracy of their subjective judgement. In addition, we investigate if the accuracy of this information depends on the strength of lenders-borrowers relationship. The objective of this paper is to understand the loan officer behaviour in default prediction task. Using credit file data from Tunisian Microfinance bank, we have found evidence that subjective judgment of loan officers has statistically significant predictive capability of default risk. In addition, our results suggest that novice loan officers have incorrect prediction of future default events because they are prone to different behavioral biases. Novice loan officers may overweight any information that is consistent with their existing beliefs and overestimate the precision of their own private information. However, through learning experienced loan officers have less behavior bias and more accurate feeling allowing them to make an accurate default prediction. To make correct decision in relationship lending approach, credit committee can rely on subjective judgment of experienced loan officers mainly when the latter judged the creditworthiness of frequent borrowers. As soft information is not easily and accurately transferable, Microfinance institutions have more interest to retain their experienced loan officers than their borrowers.

  11. Higgs boson decay into four leptons at NLOPS electroweak accuracy

    CERN Document Server

    Boselli, Stefano; Montagna, Guido; Nicrosini, Oreste; Piccinini, Fulvio

    2015-01-01

    In view of precision studies of the Higgs sector at the Run II of the LHC, the improvement of the accuracy of the theoretical prediction is becoming a pressing issue. In this framework, we detail a calculation of the full Next-to-Leading Order (NLO) electroweak corrections to Higgs boson decay into four charged leptons, by considering the gold-plated channel H -> Z(*) Z(*) -> 2l 2l', l,l' = e, mu. We match the NLO corrections with a QED Parton Shower (PS), in order to simulate exclusive multiple photon emission and provide novel results at NLOPS electroweak accuracy. We compare our NLO predictions to those of the program Prophecy4f and present NLOPS phenomenological results relevant for Higgs physics studies, with particular attention to precision measurements of the Higgs boson mass, spin-parity assignment and tests of the Standard Model. Our calculation is implemented in a new code, Hto4l, which can be easily interfaced to any generator describing Higgs boson production. As an example, we provide illustrati...

  12. Attentional bias to threat: a perceptual accuracy approach.

    Science.gov (United States)

    Van Damme, Stefaan; Crombez, Geert; Notebaert, Lies

    2008-12-01

    To investigate attentional bias to threatening information, the authors propose a new version of the spatial cueing paradigm in which the focus is on perceptual accuracy instead of response speed. In two experiments, healthy volunteers made unspeeded discriminations between three visual targets presented left or right. Each target was preceded by a visual cue (colored rectangle) at either the same (valid) or opposite (invalid) location. By means of differential classical conditioning with aversive white noise, a threat cue and a control cue were created. Analyses of error rates showed that cueing effects (lower proportion of errors in valid trials relative to invalid trials) were more pronounced in threat trials than in neutral trials. This threat-related bias was particularly because of threat cues reducing accuracy in invalid trials, indicating difficulty disengaging attention from threatening information. Engagement of attention was not affected by threat, as threat cues did not facilitate the processing of targets in valid trials. The findings are discussed in light of the strengths and limitations of spatial cueing tasks.

  13. Improving Estimation Accuracy of Aggregate Queries on Data Cubes

    Energy Technology Data Exchange (ETDEWEB)

    Pourabbas, Elaheh; Shoshani, Arie

    2008-08-15

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

  14. Improved Fast Fourier Transform Based Method for Code Accuracy Quantification

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae Wook; Jeong, Jae Jun [Pusan National University, Busan (Korea, Republic of); Choi, Ki Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The capability of the proposed method is discussed. In this study, the limitations of the FFTBM were analyzed. The FFTBM produces quantitatively different results due to its frequency dependence. Because the problem is intensified by including a lot of high frequency components, a new method using a reduced cut-off frequency was proposed. The results of the proposed method show that the shortcomings of FFTBM are considerably relieved. Among them, the fast Fourier transform based method (FFTBM) introduced in 1990 has been widely used to evaluate a code uncertainty or accuracy. Prosek et al., (2008) identified its drawbacks, the so-called 'edge effect'. To overcome the problems, an improved FFTBM by signal mirroring (FFTBM-SM) was proposed and it has been used up to now. In spite of the improvement, the FFTBM-SM yielded different accuracy depending on the frequency components of a parameter, such as pressure, temperature and mass flow rate. Therefore, it is necessary to reduce the frequency dependence of the FFTBMs. In this study, the deficiencies of the present FFTBMs are analyzed and a new method is proposed to mitigate its frequency dependence.

  15. Quantitative photoacoustic image reconstruction improves accuracy in deep tissue structures.

    Science.gov (United States)

    Mastanduno, Michael A; Gambhir, Sanjiv S

    2016-10-01

    Photoacoustic imaging (PAI) is emerging as a potentially powerful imaging tool with multiple applications. Image reconstruction for PAI has been relatively limited because of limited or no modeling of light delivery to deep tissues. This work demonstrates a numerical approach to quantitative photoacoustic image reconstruction that minimizes depth and spectrally derived artifacts. We present the first time-domain quantitative photoacoustic image reconstruction algorithm that models optical sources through acoustic data to create quantitative images of absorption coefficients. We demonstrate quantitative accuracy of less than 5% error in large 3 cm diameter 2D geometries with multiple targets and within 22% error in the largest size quantitative photoacoustic studies to date (6cm diameter). We extend the algorithm to spectral data, reconstructing 6 varying chromophores to within 17% of the true values. This quantitiative PA tomography method was able to improve considerably on filtered-back projection from the standpoint of image quality, absolute, and relative quantification in all our simulation geometries. We characterize the effects of time step size, initial guess, and source configuration on final accuracy. This work could help to generate accurate quantitative images from both endogenous absorbers and exogenous photoacoustic dyes in both preclinical and clinical work, thereby increasing the information content obtained especially from deep-tissue photoacoustic imaging studies.

  16. Selecting fillers on emotional appearance improves lineup identification accuracy.

    Science.gov (United States)

    Flowe, Heather D; Klatt, Thimna; Colloff, Melissa F

    2014-12-01

    Mock witnesses sometimes report using criminal stereotypes to identify a face from a lineup, a tendency known as criminal face bias. Faces are perceived as criminal-looking if they appear angry. We tested whether matching the emotional appearance of the fillers to an angry suspect can reduce criminal face bias. In Study 1, mock witnesses (n = 226) viewed lineups in which the suspect had an angry, happy, or neutral expression, and we varied whether the fillers matched the expression. An additional group of participants (n = 59) rated the faces on criminal and emotional appearance. As predicted, mock witnesses tended to identify suspects who appeared angrier and more criminal-looking than the fillers. This tendency was reduced when the lineup fillers matched the emotional appearance of the suspect. Study 2 extended the results, testing whether the emotional appearance of the suspect and fillers affects recognition memory. Participants (n = 1,983) studied faces and took a lineup test in which the emotional appearance of the target and fillers was varied between subjects. Discrimination accuracy was enhanced when the fillers matched an angry target's emotional appearance. We conclude that lineup member emotional appearance plays a critical role in the psychology of lineup identification. The fillers should match an angry suspect's emotional appearance to improve lineup identification accuracy.

  17. Accuracy of percutaneous lung biopsy for invasive pulmonary aspergillosis

    Energy Technology Data Exchange (ETDEWEB)

    Hoffer, F.A. [Dept. of Diagnostic Imaging, St. Jude Children' s Research Hospital, Memphis, TN (United States); Gow, K.; Davidoff, A. [Dept. of Surgery, St. Jude Children' s Research Hospital, Memphis, TN (United States); Flynn, P.M. [Dept. of Infectious Diseases, St. Jude Children' s Research Hospital, Memphis, TN (United States)

    2001-03-01

    Background. Invasive pulmonary aspergillosis is fulminant and often fatal in immunosuppressed patients. Percutaneous biopsy may select patients who could benefit from surgical resection. Objective. We sought to determine the accuracy of percutaneous biopsy for pediatric invasive pulmonary aspergillosis. Materials and methods. We retrospectively reviewed 28 imaging-guided percutaneous biopsies of the lungs of 24 children with suspected pulmonary aspergillosis. Twenty-two were being treated for malignancy and two for congenital immunodeficiency; 15 had received bone-marrow transplants. The accuracy of the percutaneous lung biopsy was determined by subsequent surgical resection, autopsy, or clinical course. Results. Histopathological studies showed ten biopsy specimens with septate hyphae, indicating a mold, and seven with Aspergillus flavus colonies in culture. The remaining 18 biopsies revealed no fungi. No patient had progressive aspergillosis after negative biopsy. Invasive pulmonary mold was detected by percutaneous biopsy with 100 % (10/10) sensitivity and 100 % (18/18) specificity. Percutaneous biopsy results influenced the surgical decision in 86 % (24 of 28) of the cases. Bleeding complicated the biopsy in 46 % (13/28) and hastened one death. Conclusion. Percutaneous biopsy of the lung is an accurate technique for the diagnosis of invasive pulmonary aspergillosis and correctly determines which immunosuppressed pediatric patients would benefit from therapeutic pulmonary resection. (orig.)

  18. Clarity Versus Accuracy and Objectivity in Written Legal English

    Directory of Open Access Journals (Sweden)

    Violeta Janulevičienė

    2011-12-01

    Full Text Available This paper is an attempt to analyse the most important grammatical and, specifically, syntactic features and to point out some prominent lexical ones, which aim at accuracy and objectivity of a written legal document, and to discuss how these features influence clarity and transparency of the legal documents. The study covers the analysis of some EU, UK, US legislative acts alongside with some extracts from contract samples. The analysis reveals that written legal English is distinguished by long compound sentences, often with inverted word order and numerous embeddings, passive constructions and nominalisations, specific use of personal pronouns and collocations of synonyms (doublets and triplets, etc. These means allow to achieve the most possible accuracy and objectivity in legal texts but make them complicated and difficult to comprehend at once. Formality, achieved by the mentioned means, makes legal English distant from everyday language and often becomes a reason for criticism. Plain English supporters encourage simplifying legal language; however, long traditions of legal English make changes slow and difficult. Therefore, comprehension and usage of legal English still requires special knowledge of its lexical and grammatical features.

  19. Photogrammetric Accuracy and Modeling of Rolling Shutter Cameras

    Science.gov (United States)

    Ye, W.; Qiao, G.; Kong, F.; Guo, S.; Ma, X.; Tong, X.; Li, R.

    2016-06-01

    Global climate change is one of the major challenges that all nations are commonly facing. Long-term observations of the Antarctic ice sheet have been playing a critical role in quantitatively estimating and predicting effects resulting from the global changes. The film-based ARGON reconnaissance imagery provides a remarkable data source for studying the Antarctic ice-sheet in 1960s, thus greatly extending the time period of Antarctica surface observations. To deal with the low-quality images and the unavailability of camera poses, a systematic photogrammetric approach is proposed to reconstruct the interior and exterior orientation information for further glacial mapping applications, including ice flow velocity mapping and mass balance estimation. Some noteworthy details while performing geometric modelling using the ARGON images were introduced, including methods and results for handling specific effects of film deformation, damaged or missing fiducial marks and calibration report, automatic fiducial mark detection, control point selection through Antarctic shadow and ice surface terrain analysis, and others. Several sites in East Antarctica were tested. As an example, four images in the Byrd glacier region were used to assess the accuracy of the geometric modelling. A digital elevation model (DEM) and an orthophoto map of Byrd glacier were generated. The accuracy of the ground positions estimated by using independent check points is within one nominal pixel of 140 m of ARGON imagery. Furthermore, a number of significant features, such as ice flow velocity and regional change patterns, will be extracted and analysed.

  20. Two proofreading steps amplify the accuracy of genetic code translation.

    Science.gov (United States)

    Ieong, Ka-Weng; Uzun, Ülkü; Selmer, Maria; Ehrenberg, Måns

    2016-11-29

    Aminoacyl-tRNAs (aa-tRNAs) are selected by the messenger RNA programmed ribosome in ternary complex with elongation factor Tu (EF-Tu) and GTP and then, again, in a proofreading step after GTP hydrolysis on EF-Tu. We use tRNA mutants with different affinities for EF-Tu to demonstrate that proofreading of aa-tRNAs occurs in two consecutive steps. First, aa-tRNAs in ternary complex with EF-Tu·GDP are selected in a step where the accuracy increases linearly with increasing aa-tRNA affinity to EF-Tu. Then, following dissociation of EF-Tu·GDP from the ribosome, the accuracy is further increased in a second and apparently EF-Tu-independent step. Our findings identify the molecular basis of proofreading in bacteria, highlight the pivotal role of EF-Tu for fast and accurate protein synthesis, and illustrate the importance of multistep substrate selection in intracellular processing of genetic information.

  1. Accuracy of the PAR corneal topography system with spatial misalignment.

    Science.gov (United States)

    Belin, M W; Zloty, P

    1993-01-01

    The PAR Corneal Topography System is a computerized corneal imaging system which uses close-range raster photogrammetry to measure and produce a topographic map of the corneal surface. Raster photogrammetry is a standard method of extracting object information by projecting a known pattern onto an object and recording the distortion when viewed from an oblique angle. Unlike placido disc based videokeratoscopes, the PAR system requires neither a smooth reflective surface nor precise spatial alignment for accurate imaging. We studied both the accuracy of the system with purposeful misalignment (defocusing) of the test object and determined the ability to image freshly deepithelialized, keratectomized, and photoablated corneas. The PAR system was both accurate and reproducible in imaging calibrated spheres within a defined zone in space. Whole cadaver eyes were imaged both before and immediately after removal of the epithelium, lamellar keratectomy, and laser photoablation. The system demonstrated the ability to image irregular, deepithelialized, and keratectomized corneas. The ability to maintain accuracy without precise alignment and the facility to image freshly deepithelialized and keratectomized corneas may make the system suitable for intraoperative refractive monitoring.

  2. Scatter dose summation for irregular fields: speed and accuracy study.

    Science.gov (United States)

    DeWyngaert, J K; Siddon, R L; Bjarngard, B E

    1986-05-01

    Using program IRREG as a standard, we have compared speed and accuracy of several algorithms that calculate the scatter dose in an irregular field. All the algorithms, in some manner, decompose the irregular field into component triangles and obtain the scatter dose as the sum of the contributions from those triangles. Two of the algorithms replace each such component triangle with a sector of a certain "effective radius": in one case the average radius of the triangle, in the other the radius of the sector having the same area as the component triangle. A third algorithm decomposes each triangle further into two right triangles and utilizes the precalculated "equivalent radius" of each, to find the scatter contribution. For points near the center of a square field, all the methods compare favorably in accuracy to program IRREG, with less than a 1% error in total dose and with approximately a factor of 3-5 savings in computation time. Even for extreme rectangular fields (2 cm X 30 cm), the methods using the average radius and the equivalent right triangles agree to within 2% in total dose and approximately a factor of 3-4 savings in computation time.

  3. Accuracy and functionality of hand held wood moisture content meters

    Energy Technology Data Exchange (ETDEWEB)

    Forsen, H.; Tarvainen, V. [VTT Building Technology, Espoo (Finland). Building Materials and Products, Wood Technology

    2000-09-01

    The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10%, 12 - 14% and 16 - 18%). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15% units/deg C which has to be considered when the moisture content of wood is measured at temperatures other than 20 deg C. The other properties of wood, such as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC

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

    Directory of Open Access Journals (Sweden)

    Ward Bryssinckx

    2012-11-01

    Full Text Available 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 <0.009 based on a sample of 2,077 parishes using one-stage stratified samples. During aggregation, area-weighted mean values were assigned to higher administrative unit levels. However, when this step is preceded by a spatial interpolation to fill in missing values in non

  5. Wind Prediction Accuracy for Air Traffic Management Decision Support Tools

    Science.gov (United States)

    Cole, Rod; Green, Steve; Jardin, Matt; Schwartz, Barry; Benjamin, Stan

    2000-01-01

    The performance of Air Traffic Management and flight deck decision support tools depends in large part on the accuracy of the supporting 4D trajectory predictions. This is particularly relevant to conflict prediction and active advisories for the resolution of conflicts and the conformance with of traffic-flow management flow-rate constraints (e.g., arrival metering / required time of arrival). Flight test results have indicated that wind prediction errors may represent the largest source of trajectory prediction error. The tests also discovered relatively large errors (e.g., greater than 20 knots), existing in pockets of space and time critical to ATM DST performance (one or more sectors, greater than 20 minutes), are inadequately represented by the classic RMS aggregate prediction-accuracy studies of the past. To facilitate the identification and reduction of DST-critical wind-prediction errors, NASA has lead a collaborative research and development activity with MIT Lincoln Laboratories and the Forecast Systems Lab of the National Oceanographic and Atmospheric Administration (NOAA). This activity, begun in 1996, has focussed on the development of key metrics for ATM DST performance, assessment of wind-prediction skill for state of the art systems, and development/validation of system enhancements to improve skill. A 13 month study was conducted for the Denver Center airspace in 1997. Two complementary wind-prediction systems were analyzed and compared to the forecast performance of the then standard 60 km Rapid Update Cycle - version 1 (RUC-1). One system, developed by NOAA, was the prototype 40-km RUC-2 that became operational at NCEP in 1999. RUC-2 introduced a faster cycle (1 hr vs. 3 hr) and improved mesoscale physics. The second system, Augmented Winds (AW), is a prototype en route wind application developed by MITLL based on the Integrated Terminal Wind System (ITWS). AW is run at a local facility (Center) level, and updates RUC predictions based on an

  6. Convective Weather Forecast Accuracy Analysis at Center and Sector Levels

    Science.gov (United States)

    Wang, Yao; Sridhar, Banavar

    2010-01-01

    This paper presents a detailed convective forecast accuracy analysis at center and sector levels. The study is aimed to provide more meaningful forecast verification measures to aviation community, as well as to obtain useful information leading to the improvements in the weather translation capacity models. In general, the vast majority of forecast verification efforts over past decades have been on the calculation of traditional standard verification measure scores over forecast and observation data analyses onto grids. These verification measures based on the binary classification have been applied in quality assurance of weather forecast products at the national level for many years. Our research focuses on the forecast at the center and sector levels. We calculate the standard forecast verification measure scores for en-route air traffic centers and sectors first, followed by conducting the forecast validation analysis and related verification measures for weather intensities and locations at centers and sectors levels. An approach to improve the prediction of sector weather coverage by multiple sector forecasts is then developed. The weather severe intensity assessment was carried out by using the correlations between forecast and actual weather observation airspace coverage. The weather forecast accuracy on horizontal location was assessed by examining the forecast errors. The improvement in prediction of weather coverage was determined by the correlation between actual sector weather coverage and prediction. observed and forecasted Convective Weather Avoidance Model (CWAM) data collected from June to September in 2007. CWAM zero-minute forecast data with aircraft avoidance probability of 60% and 80% are used as the actual weather observation. All forecast measurements are based on 30-minute, 60- minute, 90-minute, and 120-minute forecasts with the same avoidance probabilities. The forecast accuracy analysis for times under one-hour showed that the errors in

  7. Setup accuracy for prone and supine whole breast irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mulliez, Thomas; Vercauteren, Tom; Greveling, Annick van; Speleers, Bruno; Neve, Wilfried de; Veldeman, Liv [University Hospital Ghent, Department of Radiotherapy, Ghent (Belgium); Gulyban, Akos [University Hospital Ghent, Department of Radiotherapy, Ghent (Belgium); University Hospital Liege, Department of Radiotherapy, Liege (Belgium)

    2016-04-15

    To evaluate cone-beam computed tomography (CBCT) based setup accuracy and margins for prone and supine whole breast irradiation (WBI). Setup accuracy was evaluated on 3559 CBCT scans of 242 patients treated with WBI and uncertainty margins were calculated using the van Herk formula. Uni- and multivariate analysis on individual margins was performed for age, body mass index (BMI) and cup size. The population-based margin in vertical (VE), lateral (LA) and longitudinal (LO) directions was 10.4/9.4/9.4 mm for the 103 supine and 10.5/22.4/13.7 mm for the 139 prone treated patients, being significantly (p < 0.01) different for the LA and LO directions. Multivariate analysis identified a significant (p < 0.05) correlation between BMI and the LO margin in supine position and the VE/LA margin in prone position. In this series, setup accuracy is significantly worse in prone compared to supine position for the LA and LO directions. However, without proper image-guidance, uncertainty margins of about 1 cm are also necessary for supine WBI. For patients with a higher BMI, larger margins are required. (orig.) [German] Ziel der Arbeit war es, die interfraktionelle Repositionierungsgenauigkeit in Bauchlage (BL) versus Rueckenlage (RL) bei Ganzbrustbestrahlung (GBB) mittels Cone-Beam-CT (CBCT) zu bestimmen, um die notwendigen PTV-Sicherheitsabstaende zu definieren. Die Repositionierungsgenauigkeit wurde basierend an 3559 CBCT-Scans von 242 mit GBB behandelten Patienten ausgewertet. Die PTV-Sicherheitsabstaende wurden unter Verwendung der ''van-Herk''-Formel berechnet. Uni- und multivariable Analysen wurden fuer Sicherheitsabstaende in jede Richtung auf Basis von Alter, Body-Mass-Index (BMI) und Koerbchengroesse durchgefuehrt. Die basierend auf den taeglichen CBCT-Verschiebungen berechneten PTV-Sicherheitsabstaende betrugen in anteroposteriorer (AP), lateraler (LT oder links-rechts) und kraniokaudaler (CC) Richtung 10,4/9,4/9,4 mm fuer die RL (103 Patienten) und

  8. Accuracy Analysis for SST Gravity Field Model in China

    Institute of Scientific and Technical Information of China (English)

    LUO Jia; LUO Zhicai; ZOU Xiancai; WANG Haihong

    2006-01-01

    Taking China as the region for test, the potential of the new satellite gravity technique, satellite-to-satellite tracking for improving the accuracy of regional gravity field model is studied. With WDM94 as reference, the gravity anomaly residuals of three models, the latest two GRACE global gravity field model (EIGEN_GRACE02S, GGM02S) and EGM96, are computed and compared. The causes for the differences among the residuals of the three models are discussed. The comparison between the residuals shows that in the selected region, EIGEN_GRACE02S or GGM02S is better than EGM96 in lower degree part (less than 110 degree). Additionally, through the analysis of the model gravity anomaly residuals, it is found that some systematic errors with periodical properties exist in the higher degree part of EIGEN and GGM models, the results can also be taken as references in the validation of the SST gravity data.

  9. Comment on "first accuracy evaluation of NIST-F2"

    CERN Document Server

    Gibble, Kurt

    2015-01-01

    We discuss the treatment of the systematic frequency shifts due to microwave lensing and distributed cavity phase in "First accuracy evaluation of NIST-F2" 2014 Metrologia 51 174-182. We explain that the microwave lensing frequency shift is generally non-zero and finite in the limit of no applied microwave field. This systematic error was incorrectly treated and we find that it contributes a significant frequency offset. Accounting for this shift implies that the measured microwave amplitude dependence (e.g due to microwave leakage) is comparable to the total reported inaccuracy. We also discuss the importance of vertically aligning the fountain perpendicular to the axis of the cavity feeds, when the cavity has only two independent feeds. Finally, we note that background gas collisions have a different behavior for cold clock atoms than for clock atoms at room-temperature, and therefore room temperature measurements do not directly apply to laser-cooled clocks.

  10. Accuracy and precision in the calculation of phenology metrics

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Visser, Andre; MacKenzie, Brian;

    2014-01-01

    Phytoplankton phenology (the timing of seasonal events) is a commonly used indicator for evaluating responses of marine ecosystems to climate change. However, phenological metrics are vulnerable to observation-(bloom amplitude, missing data, and observational noise) and analysis-related (temporal...... resolution, preprocessing technique, and phenology metric) processes. Here we consider the impact of these processes on the robustness of four phenology metrics (timing of maximum, 5% above median, maximum growth rate, and 15% of cumulative distribution). We apply a simulation-testing approach, where...... a phenology metric is first determined from a noise- and gap-free time series, and again once it has been modified. We show that precision is a greater concern than accuracy for many of these metrics, an important point that has been hereto overlooked in the literature. The variability in precision between...

  11. Gravitational Lensing Accuracy Testing 2010 (GREAT10) Challenge Handbook

    CERN Document Server

    Kitching, Thomas; Gill, Mandeep; Harmeling, Stefan; Heymans, Catherine; Massey, Richard; Rowe, Barnaby; Schrabback, Tim; Voigt, Lisa; Balan, Sreekumar; Bernstein, Gary; Bethge, Matthias; Bridle, Sarah; Courbin, Frederic; Gentile, Marc; Heavens, Alan; Hirsch, Michael; Hosseini, Reshad; Kiessling, Alina; Kirk, Donnacha; Kuijken, Konrad; Mandelbaum, Rachel; Moghaddam, Baback; Nurbaeva, Guldariya; Paulin-Henriksson, Stephane; Rassat, Anais; Rhodes, Jason; Schölkopf, Bernhard; Shawe-Taylor, John; Shmakova, Marina; Taylor, Andy; Velander, Malin; van Waerbeke, Ludovic; Witherick, Dugan; Wittman, David

    2010-01-01

    GRavitational lEnsing Accuracy Testing 2010 (GREAT10) is a public image analysis challenge aimed at the development of algorithms to analyse astronomical images. Specifically the challenge is to measure varying image distortions in the presence of a variable convolution kernel, pixelization and noise. This is the second in a series of challenges set to the astronomy, computer science and statistics communities, providing a structured environment in which methods can be improved and tested in preparation for planned astronomical surveys. GREAT10 extends upon previous work by introducing variable fields into the challenge. The 'Galaxy Challenge' involves the precise measurement of galaxy shape distortions, quantified locally by two parameters called shear, in the presence of a known convolution kernel. Crucially, the convolution kernel and the simulated gravitational lensing shape distortion both now vary as a function of position within the images, as is the case for real data. In addition we introduce the 'St...

  12. Fitting magnetic field gradient with Heisenberg-scaling accuracy.

    Science.gov (United States)

    Zhang, Yong-Liang; Wang, Huan; Jing, Li; Mu, Liang-Zhu; Fan, Heng

    2014-12-09

    The linear function is possibly the simplest and the most used relation appearing in various areas of our world. A linear relation can be generally determined by the least square linear fitting (LSLF) method using several measured quantities depending on variables. This happens for such as detecting the gradient of a magnetic field. Here, we propose a quantum fitting scheme to estimate the magnetic field gradient with N-atom spins preparing in W state. Our scheme combines the quantum multi-parameter estimation and the least square linear fitting method to achieve the quantum Cramér-Rao bound (QCRB). We show that the estimated quantity achieves the Heisenberg-scaling accuracy. Our scheme of quantum metrology combined with data fitting provides a new method in fast high precision measurements.

  13. Accuracy and Stability of Filters for Dissipative PDEs

    CERN Document Server

    Brett, C E A; Law, K J H; McCormick, D S; Scott, M R; Stuart, A M

    2012-01-01

    Data assimilation methodologies are designed to incorporate noisy observations of a physical system into an underlying model in order to infer the properties of the state of the system. Filters refer to a class of data assimilation algorithms designed to update the estimation of the state as data is acquired sequentially. For linear problems subject to Gaussian noise filtering can be performed exactly using the Kalman filter. For nonlinear systems it can be approximated in a systematic way by particle filters. However in high dimensions these particle filtering methods can break down. Hence, for the large nonlinear systems arising in applications such as oceanography and weather forecasting, various ad hoc filters are used, based on Gaussian approximations. In this work, we study the accuracy and stability of these ad hoc filters in the context of the 2D incompressible Navier-Stokes equation. The ideas readily generalize to a range of dissipative partial differential equations (PDEs). By working in this infin...

  14. Sentinel-1A Product Geolocation Accuracy: Commissioning Phase Results

    Directory of Open Access Journals (Sweden)

    Adrian Schubert

    2015-07-01

    Full Text Available Sentinel-1A (S1A is an Earth observation satellite carrying a state-of-the-art Synthetic Aperture Radar (SAR imaging instrument. It was launched by the European Space Agency (ESA on 3 April 2014. With the end of the in-orbit commissioning phase having been completed at the end of September 2014, S1A data products are already consistently providing highly accurate geolocation. StripMap (SM mode products were acquired regularly and tested for geolocation accuracy and consistency during dedicated corner reflector (CR campaigns. At the completion of this phase, small geometric inconsistencies had been understood and mitigated, with the high quality of the final product geolocation estimates reflecting the mission’s success thus far. This paper describes the measurement campaign, the methods used during geolocation estimation, and presents best estimates of the product Absolute Location Error (ALE available at the beginning of S1A’s operational phase.

  15. The Plus or Minus Game - Teaching Estimation, Precision, and Accuracy

    Science.gov (United States)

    Forringer, Edward R.; Forringer, Richard S.; Forringer, Daniel S.

    2016-03-01

    A quick survey of physics textbooks shows that many (Knight, Young, and Serway for example) cover estimation, significant digits, precision versus accuracy, and uncertainty in the first chapter. Estimation "Fermi" questions are so useful that there has been a column dedicated to them in TPT (Larry Weinstein's "Fermi Questions.") For several years the authors (a college physics professor, a retired algebra teacher, and a fifth-grade teacher) have been playing a game, primarily at home to challenge each other for fun, but also in the classroom as an educational tool. We call the game "The Plus or Minus Game." The game combines estimation with the principle of precision and uncertainty in a competitive and fun way.

  16. Model Waveform Accuracy Requirements for the $\\chi^2$ Discriminator

    CERN Document Server

    Lindblom, Lee

    2016-01-01

    This paper derives accuracy standards for model gravitational waveforms required to ensure proper use of the $\\chi^2$ discriminator test in gravitational wave (GW) data analysis. These standards are different from previously established requirements for detection and waveform parameter measurement based on signal-to-noise optimization. We present convenient formulae both for evaluating and interpreting the contribution of model errors to measured $\\chi^2$ values. Motivated by these formula, we also present an enhanced, complexified variant of the standard $\\chi^2$ statistic used in GW searches. While our results are not directly relevant to current searches (which use the $\\chi^2$ test only to veto signal candidates with extremely high $\\chi^2$ values), they could be useful in future GW searches and as figures of merit for model gravitational waveforms.

  17. Police lie detection accuracy: the effect of lie scenario.

    Science.gov (United States)

    O'Sullivan, Maureen; Frank, Mark G; Hurley, Carolyn M; Tiwana, Jaspreet

    2009-12-01

    Although most people are not better than chance in detecting deception, some groups of police professionals have demonstrated significant lie detection accuracy. One reason for this difference may be that the types of lies police are asked to judge in scientific experiments often do not represent the types of lies they see in their profession. Across 23 studies, involving 31 different police groups in eight countries, police officers tested with lie detection scenarios using high stakes lies (i.e., the lie was personally involving and/or resulted in substantial rewards or punishments for the liar) were significantly more accurate than law enforcement officials tested with low stakes lies. Face validity and construct validity of various lie scenarios are differentiated.

  18. Spatial augmented reality based high accuracy human face projection

    Science.gov (United States)

    Li, Dong; Xie, Jinghui; Li, Yufeng; Weng, Dongdong; Liu, Yue

    2015-08-01

    This paper discusses the imaging principles and the technical difficulties of spatial augmented reality based human face projection. A novel geometry correction method is proposed to realize fast, high-accuracy face model projection. Using a depth camera to reconstruct the projected object, the relative position from the rendered model to the projector can be accessed and the initial projection image is generated. Then the projected image is distorted by using Bezier interpolation to guarantee that the projected texture matches with the object surface. The proposed method is under a simple process flow and can achieve high perception registration of virtual and real object. In addition, this method has a good performance in the condition that the reconstructed model is not exactly same with the rendered virtual model which extends its application area in the spatial augmented reality based human face projection.

  19. Improvement of SLR accuracy, a possible new step

    Science.gov (United States)

    Kasser, Michel

    1993-01-01

    The satellite laser ranging (SLR) technology experienced a large number of technical improvements since the early 1970's, leading now to a millimetric instrumental accuracy. Presently, it appears as useless to increase these instrumental performances as long as the atmospheric propagation delay suffers its actual imprecision. It has been proposed for many years to work in multiwavelength mode, but up to now the considerable technological difficulties of subpicosecond timing have seriously delayed such an approach. Then a new possibility is proposed, using a device which is not optimized now for SLR but has already given good results in the lower troposphere for wind measurement: the association of a radar and a sodar. While waiting for the 2-lambda methodology, this one could provide an atmospheric propagation delay at the millimeter level during a few years with only little technological investment.

  20. Cooperation between referees and authors increases peer review accuracy.

    Directory of Open Access Journals (Sweden)

    Jeffrey T Leek

    Full Text Available Peer review is fundamentally a cooperative process between scientists in a community who agree to review each other's work in an unbiased fashion. Peer review is the foundation for decisions concerning publication in journals, awarding of grants, and academic promotion. Here we perform a laboratory study of open and closed peer review based on an online game. We show that when reviewer behavior was made public under open review, reviewers were rewarded for refereeing and formed significantly more cooperative interactions (13% increase in cooperation, P = 0.018. We also show that referees and authors who participated in cooperative interactions had an 11% higher reviewing accuracy rate (P = 0.016. Our results suggest that increasing cooperation in the peer review process can lead to a decreased risk of reviewing errors.

  1. Read-only high accuracy volume holographic optical correlator

    Science.gov (United States)

    Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

    2011-10-01

    A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

  2. Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

    CERN Document Server

    Chou, C -W; Koelemeij, J C J; Wineland, D J; Rosenband, T

    2009-01-01

    We have constructed an optical clock with a fractional frequency inaccuracy of 8.6e-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser-cool the Al+ ion and detect its quantum state. The frequency of the 1S0->3P0 clock transition is compared to that of a previously constructed Al+ optical clock with a statistical measurement uncertainty of 7.0e-18. The two clocks exhibit a relative stability of 2.8e-15/ sqrt(tau), and a fractional frequency difference of -1.8e-17, consistent with the accuracy limit of the older clock.

  3. Neglecting Primordial non-Gaussianity Threatens Future Cosmological Experiment Accuracy

    CERN Document Server

    Camera, Stefano; Fedeli, Cosimo; Moscardini, Lauro

    2014-01-01

    Future galaxy redshift surveys aim at probing the clustering of the cosmic large-scale structure with unprecedented accuracy, thus complementing cosmic microwave background experiments in the quest of delivering the most precise and accurate picture ever of our Universe. Analyses of such measurements are usually performed within the context of the so-called vanilla LCDM model - the six-parameter phenomenological model which, for instance, emerges from best fits against the recent data obtained by the Planck satellite. Here, we show that such an approach is prone to subtle systematics when the Gaussianity of primordial fluctuations is concerned. In particular, we demonstrate that, if we neglect even a tiny amount of primordial non-Gaussianity - fully consistent with current limits - we shall introduce spurious biases in the reconstruction of cosmological parameters. This is a serious issue that must be properly accounted for in the view of accurate - besides precise - cosmology.

  4. Accuracy of Skill Performance in the Basketball Free Throw Shooting

    Directory of Open Access Journals (Sweden)

    Igawa Shoji

    2011-12-01

    Full Text Available The purpose of this study were to investigates how timing of shot of skilled player and assess performance accuracy of free throw shooting. Ten college students participated in this study (5 skilled players, and 5 naïve participants aged 18-23 years. They performed free throw shooting at 10 times. Shooting seen was recorded three cameras and analyzed shooting successful rate, off-target distance (the distance between the basketball through point and the center of the goal and shot timing. Shot timing was not significant difference. Shooting successful rate of skilled players was higher than unskilled players. Offtarget distance of skilled players was significant smaller than naive player. Consequently, skilled player is possible to aim at the center of the goal and shooting near the center of goal.

  5. Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

    Science.gov (United States)

    Chou, C. W.; Hume, D. B.; Koelemeij, J. C. J.; Wineland, D. J.; Rosenband, T.

    2010-02-01

    We have constructed an optical clock with a fractional frequency inaccuracy of 8.6×10-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser cool the Al+ ion and detect its quantum state. The frequency of the S01↔P03 clock transition is compared to that of a previously constructed Al+ optical clock with a statistical measurement uncertainty of 7.0×10-18. The two clocks exhibit a relative stability of 2.8×10-15τ-1/2, and a fractional frequency difference of -1.8×10-17, consistent with the accuracy limit of the older clock.

  6. Stability and Accuracy Analysis for Taylor Series Numerical Method

    Institute of Scientific and Technical Information of China (English)

    赵丽滨; 姚振汉; 王寿梅

    2004-01-01

    The Taylor series numerical method (TSNM) is a time integration method for solving problems in structural dynamics. In this paper, a detailed analysis of the stability behavior and accuracy characteristics of this method is given. It is proven by a spectral decomposition method that TSNM is conditionally stable and belongs to the category of explicit time integration methods. By a similar analysis, the characteristic indicators of time integration methods, the percentage period elongation and the amplitude decay of TSNM, are derived in a closed form. The analysis plays an important role in implementing a procedure for automatic searching and finding convergence radii of TSNM. Finally, a linear single degree of freedom undamped system is analyzed to test the properties of the method.

  7. Euler Deconvolution with Improved Accuracy and Multiple Different Structural Indices

    Institute of Scientific and Technical Information of China (English)

    G R J Cooper

    2008-01-01

    Euler deconvolution is a semi-automatic interpretation method that is frequently used with magnetic and gravity data. For a given source type, which is specified by its structural index (SI), it provides an estimate of the source location. It is demonstrated here that by computing the solution space of individual data points and selecting common source locations the accuracy of the result can be improved. Furthermore, only a slight modification of the method is necessary to allow solutions for any number of different Sis to be obtained simultaneously. The method is applicable to both evenly and unevenly sampled geophysical data and is demonstrated on gravity and magnetic data. Source code (in Matlab format) is available from www.iamg.org.

  8. HOW DIFFERENT VARIABLES AFFECT THE ACCURACY OF HAND-TIMING

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To analyze the process of hand-timing and the resulting data collected from the hand-timing computer system(HTCS),including the timing operator′s reaction times of starting and stopping the watch,the results from the timing,the simulated electronic timing,the major factor that affects the time-keeper′s accuracy of time-keeping were studied,i.e.the stability of the time-keeper′s reaction time,rather than the time-keeper′s reation time.The leading cause that inflicts error between the hand-time-keeping and the electrionic time-keeping consists in the pitfall that the time-keeper makes a wrong judgment in stopping the watch.The analytical results provide theoretic gist for the selection and training of time-keeping operators.

  9. Limit cycles, bifurcations, and accuracy of the milling process

    Science.gov (United States)

    Mann, B. P.; Bayly, P. V.; Davies, M. A.; Halley, J. E.

    2004-10-01

    Time finite element analysis (TFEA) is used to determine the accuracy, stability, and limit cycle behavior of the milling process. Predictions are compared to traditional Euler simulation and experiments. The TFEA method forms an approximate solution by dividing the time in the cut into a finite number of elements. The approximate solution is then matched with the exact solution for free vibration to obtain a discrete linear map. Stability is then determined from the characteristic multipliers of the map. Map fixed points correspond to stable periodic solutions which are used to evaluate surface location error. Bifurcations and limit cycle behavior are predicted from a non-linear TFEA formulation. Experimental cutting tests are used to confirm theoretical predictions.

  10. Accuracy of the Danish version of the 'distress thermometer'

    DEFF Research Database (Denmark)

    Bidstrup, Pernille Envold; Mertz, Birgitte; Dalton, Susanne Oksbjerg

    2012-01-01

    Objective: Short screening instruments have been suggested to improve the detection of psychological symptoms. We examined the accuracy of the Danish version of the 'Distress Thermometer'. Methods: Between October 2008 and October 2009, 426 women with newly diagnosed primary breast cancer who were...... for referral for psychological support. Results: A cut-off score of 6 vs 7 (low:¿6, high:¿7) on the distress thermometer was optimal for confirming distress, with a sensitivity of 42%, a specificity of 93%, a positive predictive value (PPV) of 78% and a negative predictive value (NPV) of 73%. A cut-off score...... operated at the Breast Surgery Clinic of the Rigshospitalet, Copenhagen, were eligible for this study. Of these, 357 participated (84%) and 333 completed a questionnaire. The distress thermometer was evaluated against the 'hospital anxiety and depression scale' (HADS). We also examined the women's wish...

  11. The generalized radon transform: Sampling, accuracy and memoryconsiderations

    Energy Technology Data Exchange (ETDEWEB)

    Luengo Hendriks, Cris L.; van Ginkel, Michael; Verbeek, Piet W.; van Vliet, Lucas J.

    2004-09-23

    The generalized Radon (or Hough) transform is a well-known tool for detecting parameterized shapes in an image. The Radon transform is a mapping between the image space and a parameter space. The coordinates of a point in the latter correspond to the parameters of a shape in the image. The amplitude at that point corresponds to the amount of evidence for that shape. In this paper we discuss three important aspects of the Radon transform. The first aspect is discretization. Using concepts from sampling theory we derive a set of sampling criteria for the generalized Radon transform. The second aspect is accuracy. For the specific case of the Radon transform for spheres, we examine how well the location of the maxima matches the true parameters. We derive a correction term to reduce the bias in the estimated radii. The third aspect concerns a projection-based algorithm to reduce memory requirements.

  12. ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES

    Directory of Open Access Journals (Sweden)

    Dita Jiroutová

    2013-12-01

    Full Text Available In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field, corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.

  13. The Third Gravitational Lensing Accuracy Testing (GREAT3) Challenge Handbook

    CERN Document Server

    Mandelbaum, Rachel; Bosch, James; Chang, Chihway; Courbin, Frederic; Gill, Mandeep; Jarvis, Mike; Kannawadi, Arun; Kacprzak, Tomasz; Lackner, Claire; Leauthaud, Alexie; Miyatake, Hironao; Nakajima, Reiko; Rhodes, Jason; Simet, Melanie; Zuntz, Joe; Armstrong, Bob; Bridle, Sarah; Coupon, Jean; Dietrich, Jörg P; Gentile, Marc; Heymans, Catherine; Jurling, Alden S; Kent, Stephen M; Kirkby, David; Margala, Daniel; Massey, Richard; Melchior, Peter; Peterson, John; Roodman, Aaron; Schrabback, Tim

    2013-01-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. The GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include realistically complex galaxy models based on high-resolution imaging from space; spatially varying blurring kernel; and combination of multiple different exposures. To facilitate entry by p...

  14. Fiducialisation and initial alignment of CLIC component with micrometric accuracy

    CERN Document Server

    Mainaud Durand, Helene; Buzio, Marco; Caiazza, Domenico; Catalan Lasheras, Nuria; Cherif, Ahmed; Doytchinov, Iordan Petrov; Fuchs, Jean-Frederic; Gaddi, Andrea; Galindo Munoz, Natalia; Gayde, Jean-Christophe; Kamugasa, Solomon William; Modena, Michele; Novotny, Peter; Sanz, Claude; Severino, Giordana; Russenschuck, Stephan; Tshilumba, David; Vlachakis, Vasileios; Wendt, Manfred; Zorzetti, Silvia; CERN. Geneva. ATS Department

    2016-01-01

    We propose a new solution to fiducialise the three major components of the CLIC collider: quadrupoles, beam-position monitors (BPM), and accelerating structures (AS). This solution is based on the use of a copper-beryllium (CuBe) wire to locate the reference position, i.e. the symmetry axes of the components (their magnetic, respectively electromagnetic centre axis), and to determine their position in the common support assembly defining a local coordinate system, with respect to the fiducials. These alignment targets will be used later to align the support assembly in the tunnel. With such a method, several accelerator components of different types, supported by a dedicated adjustment system, can be simultaneously fiducialised and pre-aligned using the same wire, enabling a micrometric accuracy with help of a 3D coordinate measurement machine (CMM). Alternative solutions based on frequency scanning interferometry (FSI) and micro-triangulation are also under development, to perform such fiducialisation and in...

  15. Researching the technology of high-accuracy camshaft measurement

    Science.gov (United States)

    Chen, Wei; Chen, Yong-Le; Wang, Hong; Liao, Hai-Yang

    1996-10-01

    This paper states the cam's data processing algorithm in detail in high accurate camshaft measurement system. It contains: 1) using minimum error of curve symmetry to seek the center position of the key slot; 2) Calculating the minimum error by cam's curve in theory to search top area; 3) According to cam's tolerance E(i) function and minimum angle error at cam top, seeking the best position of cam top and getting the best angle value and error curve. The algorithm is suitable for measuring all kinds of symmetry or asymmetry cam, and plain push-rod or spherical push-rod cam, for example, bus camshaft, car camshaft, motor camshaft, etc. Using the algorithm, high accuracy measurement can be achieved.

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

    CERN Document Server

    Del Duca, Vittorio; Somogyi, Gabor; Tramontano, Francesco; Trocsanyi, Zoltan

    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.

  17. Measuring Intuition: Nonconscious Emotional Information Boosts Decision Accuracy and Confidence.

    Science.gov (United States)

    Lufityanto, Galang; Donkin, Chris; Pearson, Joel

    2016-05-01

    The long-held popular notion of intuition has garnered much attention both academically and popularly. Although most people agree that there is such a phenomenon as intuition, involving emotionally charged, rapid, unconscious processes, little compelling evidence supports this notion. Here, we introduce a technique in which subliminal emotional information is presented to subjects while they make fully conscious sensory decisions. Our behavioral and physiological data, along with evidence-accumulator models, show that nonconscious emotional information can boost accuracy and confidence in a concurrent emotion-free decision task, while also speeding up response times. Moreover, these effects were contingent on the specific predictive arrangement of the nonconscious emotional valence and motion direction in the decisional stimulus. A model that simultaneously accumulates evidence from both physiological skin conductance and conscious decisional information provides an accurate description of the data. These findings support the notion that nonconscious emotions can bias concurrent nonemotional behavior-a process of intuition.

  18. Accuracy of Heart Rate Watches: Implications for Weight Management.

    Directory of Open Access Journals (Sweden)

    Matthew P Wallen

    Full Text Available Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established.To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha to measure heart rate and energy expenditure at rest and during exercise.Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate and indirect calorimetry (energy expenditure.None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67-0.95 [0.35 to 0.98] and weak to strong for energy expenditure (0.16-0.86 [-0.25 to 0.95]. All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1-9% but greater for energy expenditure (9-43%. Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm than energy expenditure (ranging from -266.7 to 65.7 kcals across devices.These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss.

  19. Accuracy of FibroScan for diagnosing liver fibrosis

    Directory of Open Access Journals (Sweden)

    Jian ZHANG

    2011-11-01

    Full Text Available Objective To evaluate the accuracy of transient elastometry(FibroScan for the detection of liver fibrosis.Methods A total of 323 patients diagnosed with chronic liver disease based on pathological examination in the 302 Hospital of the People’s Liberation Army from April to December of 2009 were involved in the current study.Among them,141 patients were subjected to liver biopsy.Their liver function,coagulant index,B-ultrasound and blood cell count were examined clinically.Four examinations related to liver fibrosis were done on some of the patients.Meanwhile,FibroScan was used for liver stiffness measurement(LSM of every patient.The correlation between liver stiffness and the serologic index and liver fibrosis degree was analyzed.The Receive Operating Characteristic(ROC curve was adopted to analyze the accuracy of FibroScan for diagnosing liver fibrosis.Results Each serologic index was significantly correlated with liver stiffness(P < 0.001,and liver stiffness was closely related to the stage of liver fibrosis(r=0.74,P < 0.001.The statistical results of the 141 patients who underwent pathologic examination show that the areas under the ROC curve were 0.97(0.94,1.00 for patients with portal fibrosis(F1,0.96(0.93,0.99 for patients with significant fibrosis(F2,0.99(0.98,1.00 for patients with severe fibrosis(F3,and 0.97(0.94,0.99 for patients with cirrhosis(F4.The cutoff values were 4.4KPa,6.8KPa,9.7KPa,and 10.0KPa,respectively.Conclusion FibroScan is valuable for the diagnosis of liver fibrosis.It can be used as the basis for follow-up and management of patients with chronic liver diseases.

  20. Prostate-specific antigen testing accuracy in community practice

    Directory of Open Access Journals (Sweden)

    Adams-Cameron Meg

    2002-10-01

    Full Text Available Abstract Background Most data on prostate-specific antigen (PSA testing come from urologic cohorts comprised of volunteers for screening programs. We evaluated the diagnostic accuracy of PSA testing for detecting prostate cancer in community practice. Methods PSA testing results were compared with a reference standard of prostate biopsy. Subjects were 2,620 men 40 years and older undergoing (PSA testing and biopsy from 1/1/95 through 12/31/98 in the Albuquerque, New Mexico metropolitan area. Diagnostic measures included the area under the receiver-operating characteristic curve, sensitivity, specificity, and likelihood ratios. Results Cancer was detected in 930 subjects (35%. The area under the ROC curve was 0.67 and the PSA cutpoint of 4 ng/ml had a sensitivity of 86% and a specificity of 33%. The likelihood ratio for a positive test (LR+ was 1.28 and 0.42 for a negative test (LR-. PSA testing was most sensitive (90% but least specific (27% in older men. Age-specific reference ranges improved specificity in older men (49% but decreased sensitivity (70%, with an LR+ of 1.38. Lowering the PSA cutpoint to 2 ng/ml resulted in a sensitivity of 95%, a specificity of 20%, and an LR+ of 1.19. Conclusions PSA testing had fair discriminating power for detecting prostate cancer in community practice. The PSA cutpoint of 4 ng/ml was sensitive but relatively non-specific and associated likelihood ratios only moderately revised probabilities for cancer. Using age-specific reference ranges and a PSA cutpoint below 4 ng/ml improved test specificity and sensitivity, respectively, but did not improve the overall accuracy of PSA testing.

  1. Accuracy of Canadian Food Labels for Sodium Content of Food

    Directory of Open Access Journals (Sweden)

    Laura Fitzpatrick

    2014-08-01

    Full Text Available The accuracy of the Nutrition Facts table (NFt has a significant impact on Canadian efforts to reduce dietary sodium and monitor sodium content in foods. This study assessed the accuracy of sodium (and calories, trans fat, saturated fat, sugar reported on the NFt for selected foods and beverages in Canada. The Canadian Food Inspection Agency (CFIA sampled over 1000 foods and beverages from supermarkets, bakeries, and restaurants across Canada between January 2006 and December 2010. The samples were analyzed in CFIA laboratories. Results were requested for products with ≥1 of the following nutrients tested: sodium, calories, saturated fat, trans fat, and sugar. Differences between the label and laboratory values were calculated for each product. Overall, 16.7% (n = 169 of products were “unsatisfactory” with laboratory values exceeding ±20% of the NFt value. Sodium had the highest number of unsatisfactory products (n = 49, 18.4% and trans fat had the lowest number of unsatisfactory products (n = 16, 4.3%. The proportion of unsatisfactory products for saturated fat, calories, and sugar was 15.8%, 14.2%, and 12.9%, respectively. All of the unsatisfactory products had excess nutrient content relative to the NFt. Sodium and calories were consistently underreported (p < 0.05, while NFt values for the other nutrients were not statistically different than laboratory values. Increased monitoring of NFt sodium values is recommended in order to increase consumer confidence in this nutrition tool, to encourage industry to accurately report nutrient content and to continue using the NFt to guide research, education, and policy development.

  2. Diagnostic accuracy of the bronchodilator response in children

    Science.gov (United States)

    Tse, Sze Man; Gold, Diane R.; Sordillo, Joanne E.; Hoffman, Elaine B.; Gillman, Matthew W.; Rifas-Shiman, Sheryl L.; Fuhlbrigge, Anne L.; Tantisira, Kelan G.; Weiss, Scott T.; Litonjua, Augusto A.

    2013-01-01

    Background The bronchodilator response (BDR) reflects the reversibility of airflow obstruction and is recommended as an adjunctive test to diagnose asthma. The validity of the commonly used definition of BDR, a 12% or greater change in FEV1 from baseline, has been questioned in childhood. Objectives We sought to examine the diagnostic accuracy of the BDR test by using 3 large pediatric cohorts. Methods Cases include 1041 children with mild-to-moderate asthma from the Childhood Asthma Management Program. Control subjects (nonasthmatic and nonwheezing) were chosen from Project Viva and Home Allergens, 2 population-based pediatric cohorts. Receiver operating characteristic curves were constructed, and areas under the curve were calculated for different BDR cutoffs. Results A total of 1041 cases (59.7% male; mean age, 8.9 ± 2.1 years) and 250 control subjects (46.8% male; mean age, 8.7 ± 1.7 years) were analyzed, with mean BDRs of 10.7% ± 10.2% and 2.7% ± 8.4%, respectively. The BDR test differentiated asthmatic patients from nonasthmatic patients with a moderate accuracy (area under the curve, 73.3%). Despite good specificity, a cutoff of 12% was associated with poor sensitivity (35.6%). A cutoff of less than 8% performed significantly better than a cutoff of 12% (P = .03, 8% vs 12%). Conclusions Our findings highlight the poor sensitivity associated with the commonly used 12% cutoff for BDR. Although our data show that a threshold of less than 8% performs better than 12%, given the variability of this test in children, we conclude that it might be not be appropriate to choose a specific BDR cutoff as a criterion for the diagnosis of asthma. PMID:23683464

  3. Speed Accuracy Trade-off Under Response Deadlines

    Directory of Open Access Journals (Sweden)

    Hakan eKarşılar

    2014-08-01

    Full Text Available Perceptual decision making has been successfully modeled as a process of evidence accumulation up to a threshold. In order to maximize the rewards earned for correct responses in tasks with response deadlines, participants should collapse decision thresholds dynamically during each trial so that a decision is reached before the deadline. This strategy ensures on-time responding, though at the cost of reduced accuracy, since slower decisions are based on lower thresholds and less net evidence later in a trial (compared to a constant threshold. Frazier & Yu (2008 showed that the normative rate of threshold reduction depends on deadline delays and on participants’ uncertainty about these delays. Participants should start collapsing decision thresholds earlier when making decisions under shorter deadlines (for a given level of timing uncertainty or when timing uncertainty is higher (for a given deadline. We tested these predictions using human participants in a random dot motion discrimination task. Each participant was tested in free-response, short deadline (800 ms, and long deadline conditions (1000 ms. Contrary to optimal-performance predictions, the resulting empirical function relating accuracy to response time (RT in deadline conditions did not decline to chance level near the deadline; nor did the slight decline we typically observed relate to measures of endogenous timing uncertainty. Further, although this function did decline slightly with increasing RT, the decline was explainable by the best-fitting parameterization of Ratcliff's diffusion model (Ratcliff, 1978, whose parameters are constant within trials. Our findings suggest that at the very least, typical decision durations are too short for participants to adapt decision parameters within trials.

  4. Diagnostic accuracy of laser evoked potentials in diabetic neuropathy.

    Science.gov (United States)

    Di Stefano, G; La Cesa, S; Leone, C; Pepe, A; Galosi, E; Fiorelli, M; Valeriani, M; Lacerenza, M; Pergolini, M; Biasiotta, A; Cruccu, G; Truini, A

    2017-03-04

    Although the most widely agreed neurophysiological tool for investigating small fibre damage is laser evoked potential (LEP) recording, no study has documented its diagnostic accuracy. In this clinical, neurophysiological and skin biopsy study we collected age-corrected LEP normative ranges, verified the association of LEPs with pinprick sensory disturbances in the typical diabetic mixed-fibre polyneuropathy and assessed the sensitivity and specificity of LEPs in diabetic small-fibre neuropathy.From 288 LEP recordings from the face, hand and foot in 73 healthy subjects we collected age-corrected normative ranges for LEPs. We then selected 100 patients with mixed-fibre diabetic neuropathy and 25 patients with possible small-fibre diabetic neuropathy. In the 100 patients with mixed-fibre neuropathy we verified how LEP abnormalities were associated with clinically evident pinprick sensory disturbances. In the 25 patients with possible pure small-fibre neuropathy, using the skin biopsy for assessing the intraepidermal nerve fibre density, as a reference standard, we calculated LEP sensitivity and specificity.In healthy participants, age strongly influenced normative ranges for all LEP variables. By applying age-corrected normative ranges for LEPs, we found that LEPs were strongly associated with pinprick sensory disturbances. In relation to the skin biopsy findings, LEPs yielded 78% sensitivity and 81% specificity in the diagnosis of diabetic small-fibre neuropathy.Our study, providing age-corrected normative ranges for the main LEP data and their diagnostic accuracy, helps to make LEPs more reliable as a clinical diagnostic tool, and proposes this technique as a less invasive alternative to skin biopsy for diagnosing diabetic small-fibre neuropathy.

  5. Geometric accuracy of topographical objects at Polish topographic maps

    Directory of Open Access Journals (Sweden)

    Ławniczak Radzym

    2016-06-01

    Full Text Available The objective of research concerned verifying the accuracy of the location and shape of selected lakes presented on topographical maps from various periods, drawn up on different scales. The area of research covered lakes situated in North-Western Poland on the Międzychód-Sieraków Lakeland. An analysis was performed of vector maps available in both analogue and digital format. The scales of these studies range from 1:50 000 to 1:10 000. The source materials were current for the years 1907 through 2013. The shape and location of lakes have been verified directly by means of field measurements performed using the GPS technology with an accuracy class of RTK. An analysis was performed of the location and shape of five lakes. The analysed water regions were vectorised, and their vector images were used to determine quantitative features: the area and length of the shoreline. Information concerning the analysed lakes obtained from the maps was verified on the basis of direct field measurements performed using a GPS RTK receiver. Use was made of georeferential corrections provided by the NAVGEO service or a virtual reference station generated by the ASG EUPOS system. A compilation of cartographic and field data formed the basis for a comparison of the actual area and the length of the shoreline of the studied lakes. Cartographic analyses made it possible to single out the most reliable cartographic sources, which could be used for the purposes of hydrographical analyses. The course of shorelines shows the attached map.

  6. Geometric accuracy of topographical objects at Polish topographic maps

    Science.gov (United States)

    Ławniczak, Radzym; Kubiak, Jarosław

    2016-06-01

    The objective of research concerned verifying the accuracy of the location and shape of selected lakes presented on topographical maps from various periods, drawn up on different scales. The area of research covered lakes situated in North-Western Poland on the Międzychód-Sieraków Lakeland. An analysis was performed of vector maps available in both analogue and digital format. The scales of these studies range from 1:50 000 to 1:10 000. The source materials were current for the years 1907 through 2013. The shape and location of lakes have been verified directly by means of field measurements performed using the GPS technology with an accuracy class of RTK. An analysis was performed of the location and shape of five lakes. The analysed water regions were vectorised, and their vector images were used to determine quantitative features: the area and length of the shoreline. Information concerning the analysed lakes obtained from the maps was verified on the basis of direct field measurements performed using a GPS RTK receiver. Use was made of georeferential corrections provided by the NAVGEO service or a virtual reference station generated by the ASG EUPOS system. A compilation of cartographic and field data formed the basis for a comparison of the actual area and the length of the shoreline of the studied lakes. Cartographic analyses made it possible to single out the most reliable cartographic sources, which could be used for the purposes of hydrographical analyses. The course of shorelines shows the attached map.

  7. Selective effect of physical fatigue on motor imagery accuracy.

    Directory of Open Access Journals (Sweden)

    Franck Di Rienzo

    Full Text Available While the use of motor imagery (the mental representation of an action without overt execution during actual training sessions is usually recommended, experimental studies examining the effect of physical fatigue on subsequent motor imagery performance are sparse and yielded divergent findings. Here, we investigated whether physical fatigue occurring during an intense sport training session affected motor imagery ability. Twelve swimmers (nine males, mean age 15.5 years conducted a 45 min physically-fatiguing protocol where they swam from 70% to 100% of their maximal aerobic speed. We tested motor imagery ability immediately before and after fatigue state. Participants randomly imagined performing a swim turn using internal and external visual imagery. Self-reports ratings, imagery times and electrodermal responses, an index of alertness from the autonomic nervous system, were the dependent variables. Self-reports ratings indicated that participants did not encounter difficulty when performing motor imagery after fatigue. However, motor imagery times were significantly shortened during posttest compared to both pretest and actual turn times, thus indicating reduced timing accuracy. Looking at the selective effect of physical fatigue on external visual imagery did not reveal any difference before and after fatigue, whereas significantly shorter imagined times and electrodermal responses (respectively 15% and 48% decrease, p<0.001 were observed during the posttest for internal visual imagery. A significant correlation (r=0.64; p<0.05 was observed between motor imagery vividness (estimated through imagery questionnaire and autonomic responses during motor imagery after fatigue. These data support that unlike local muscle fatigue, physical fatigue occurring during intense sport training sessions is likely to affect motor imagery accuracy. These results might be explained by the updating of the internal representation of the motor sequence, due to

  8. Accuracy assessment of gridded precipitation datasets in the Himalayas

    Science.gov (United States)

    Khan, A.

    2015-12-01

    Accurate precipitation data are vital for hydro-climatic modelling and water resources assessments. Based on mass balance calculations and Turc-Budyko analysis, this study investigates the accuracy of twelve widely used precipitation gridded datasets for sub-basins in the Upper Indus Basin (UIB) in the Himalayas-Karakoram-Hindukush (HKH) region. These datasets are: 1) Global Precipitation Climatology Project (GPCP), 2) Climate Prediction Centre (CPC) Merged Analysis of Precipitation (CMAP), 3) NCEP / NCAR, 4) Global Precipitation Climatology Centre (GPCC), 5) Climatic Research Unit (CRU), 6) Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), 7) Tropical Rainfall Measuring Mission (TRMM), 8) European Reanalysis (ERA) interim data, 9) PRINCETON, 10) European Reanalysis-40 (ERA-40), 11) Willmott and Matsuura, and 12) WATCH Forcing Data based on ERA interim (WFDEI). Precipitation accuracy and consistency was assessed by physical mass balance involving sum of annual measured flow, estimated actual evapotranspiration (average of 4 datasets), estimated glacier mass balance melt contribution (average of 4 datasets), and ground water recharge (average of 3 datasets), during 1999-2010. Mass balance assessment was complemented by Turc-Budyko non-dimensional analysis, where annual precipitation, measured flow and potential evapotranspiration (average of 5 datasets) data were used for the same period. Both analyses suggest that all tested precipitation datasets significantly underestimate precipitation in the Karakoram sub-basins. For the Hindukush and Himalayan sub-basins most datasets underestimate precipitation, except ERA-interim and ERA-40. The analysis indicates that for this large region with complicated terrain features and stark spatial precipitation gradients the reanalysis datasets have better consistency with flow measurements than datasets derived from records of only sparsely distributed climatic

  9. Quantification of Proton Dose Calculation Accuracy in the Lung

    Energy Technology Data Exchange (ETDEWEB)

    Grassberger, Clemens, E-mail: Grassberger.Clemens@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Center for Proton Radiotherapy, Paul Scherrer Institute, Villigen (Switzerland); Daartz, Juliane; Dowdell, Stephen; Ruggieri, Thomas; Sharp, Greg; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)

    2014-06-01

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

  10. Diagnostic Accuracy of Cincinnati Pre-Hospital Stroke Scale

    Directory of Open Access Journals (Sweden)

    Behzad Zohrevandi

    2015-07-01

    Full Text Available Introduction: Stroke is recognized as the third cause of mortality after cardiovascular and cancer diseases, so that lead to death of about 5 million people, annually. There are several scales to early prediction of at risk patients and decreasing the rate of mortality by transferring them to the stroke center. In the present study, the accuracy of Cincinnati pre-hospital stroke scale was assessed. Methods: This was a retrospective cross-sectional study done to assess accuracy of Cincinnati scale in prediction of stroke probability in patients referred to the emergency department of Poursina Hospital, Rasht, Iran, 2013 with neurologic symptoms. Three criteria of Cincinnati scale including facial droop, dysarthria, and upper extremity weakness as well as the final diagnosis of patients were gathered. Sensitivity, specificity, predictive values, and likelihood ratios of Cincinnati scale were calculated using SPSS version 20. Results: 448 patients were assessed. The agreement rate of Cincinnati scale and final diagnosis was 0.483 ± 0.055 (p<0.0001. The sensitivity of 93.19% (95% Cl: 90.11-95.54, specificity of 51.85% (95% Cl: 40.47-63.10, positive predictive value of 89.76% (95% Cl: 86.27-92.62, negative predictive value of 62.69% (95% Cl: 55.52-72.45, positive likelihood ratio of 1.94% (95% Cl: 1.54-2.43, and negative likelihood ratio of 0.13% (95% Cl: 0.09-0.20 were calculated. Conclusion: It seems that pre-hospital Cincinnati scale can be an appropriate screening tool in prediction of stroke in patients with acute neurologic syndromes.

  11. The accuracy of stereolithography in planning craniofacial bone replacement.

    Science.gov (United States)

    Chang, Peter Shih-Hsin; Parker, Thornwell H; Patrick, Charles W; Miller, Michael J

    2003-03-01

    Stereolithography can be used to produce physical models of the craniofacial skeleton from three-dimensional computed tomography (CT) data. The purpose of this study was to assess its accuracy for modeling osseous defects of the midface. Maxillary resections simulating unilateral maxillectomy (N = 3), bilateral maxillectomy (N = 3), and unilateral orbitomaxillectomy (N = 3) were performed as for sinus tumor resection on nine fresh cadaver skulls. Stereolithographic models (SLMs) were made from the specimen's CT data. The accuracy of SLMs was determined by comparing distances between key landmarks on the skulls and SLMs. Each SLM was grossly accurate with some loss of thin delicate structures. The mean differences in overall dimensions between the SLMs and skull specimens were 1.5 mm (range: 0-5.5 mm) for craniofacial measures, 1.2 mm (range: 0-4.8 mm) for skull base measures, 1.6 (range: 0-5.8 mm) for midface measures, 1.9 mm (range: 0-7.9 mm) for maxilla measures, and 1.5 mm (range: 0-5.7 mm) for orbital measures. The mean differences in defect dimensions were 1.9 mm (range: 0.1-5.7 mm) for unilateral maxillectomy, 0.8 mm (range: 0.2-1.5 mm) for bilateral maxillectomy, and 2.5 mm (range: 0.2-7.0 mm) for orbitomaxillectomy defects. Midface SLMs may be more prone to error than those of other craniofacial regions because of the presence of thin walls and small projections. Thus, one should consider designing midface bone replacements that are larger in critical dimensions than those predicted by preoperative modeling. These findings have important implications for the planning of current surgical methods as well as future applications of tissue-engineered bone replacement.

  12. Avoiding the ventricle : a simple step to improve accuracy of anatomical targeting during deep brain stimulation

    NARCIS (Netherlands)

    Zrinzo, Ludvic; van Hulzen, Arjen L. J.; Gorgulho, Alessandra A.; Limousin, Patricia; Staal, Michiel J.; De Salles, Antonio A. F.; Hariz, Marwan I.

    2009-01-01

    Object. The authors examined the accuracy of anatomical targeting during electrode implantation for deep brain stimulation in functional neurosurgical procedures. Special attention was focused on the impact that ventricular involvement of the electrode trajectory had on targeting accuracy. Methods.

  13. Accuracy Assessment Points for Florissant Fossil Beds National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in July - August, 2001 to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS...

  14. Accuracy Assessment Points for Gateway National Recreation Area Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Location of thematic accuracy assessment sampling points, that were field sampled, based on the destination accuracy assessment points used in the vegetation mapping...

  15. Accuracy Assessment Points for Scotts Bluff National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in August, 1997 to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS...

  16. Accuracy Assessment Points for Wind Cave National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS Vegetation Mapping...

  17. Accuracy Assessment Points for Devils Tower National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in July and August, 1996 to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS...

  18. Accuracy Assessment Points for Fort Laramie National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in August and September, 1998 to verify the accuracy of the vegetation communities spatial data developed by the...

  19. Accuracy Assessment Points for Mount Rushmore National Memorial Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The accuracy assessment field work was performed in July and August, 1996 to verify the accuracy of the vegetation communities spatial data developed by the USGS-NPS...

  20. Inference of Altimeter Accuracy on Along-track Gravity Anomaly Recovery

    Directory of Open Access Journals (Sweden)

    LI Yang

    2015-04-01

    Full Text Available A correlation model between along-track gravity anomaly accuracy, spatial resolution and altimeter accuracy is proposed. This new model is based on along-track gravity anomaly recovery and resolution estimation. Firstly, an error propagation formula of along-track gravity anomaly is derived from the principle of satellite altimetry. Then the mathematics between the SNR (signal to noise ratio and cross spectral coherence is deduced. The analytical correlation between altimeter accuracy and spatial resolution is finally obtained from the results above. Numerical simulation results show that along-track gravity anomaly accuracy is proportional to altimeter accuracy, while spatial resolution has a power relation with altimeter accuracy. e.g., with altimeter accuracy improving m times, gravity anomaly accuracy improves m times while spatial resolution improves m0.4644 times. This model is verified by real-world data.

  1. MAPPING SPATIAL ACCURACY AND ESTIMATING LANDSCAPE INDICATORS FROM THEMATIC LAND COVER MAPS USING FUZZY SET THEORY

    Science.gov (United States)

    The accuracy of thematic map products is not spatially homogenous, but instead variable across most landscapes. Properly analyzing and representing the spatial distribution (pattern) of thematic map accuracy would provide valuable user information for assessing appropriate applic...

  2. Office of Adolescent Health medical accuracy review process--helping ensure the medical accuracy of Teen Pregnancy Prevention Program materials.

    Science.gov (United States)

    Jensen, Jo Anne G; Moreno, Elizabeth L; Rice, Tara M

    2014-03-01

    The Office of Adolescent Health (OAH) developed a systematic approach to review for medical accuracy the educational materials proposed for use in Teen Pregnancy Prevention (TPP) programs. This process is also used by the Administration on Children, Youth, and Families (ACYF) for review of materials used in the Personal Responsibility Education Innovative Strategies (PREIS) Program. This article describes the review process, explaining the methodology, the team implementing the reviews, and the process for distributing review findings and implementing changes. Provided also is the definition of "medically accurate and complete" as used in the programs, and a description of what constitutes "complete" information when discussing sexually transmitted infections and birth control methods. The article is of interest to program providers, curriculum developers and purveyors, and those who are interested in providing medically accurate and complete information to adolescents.

  3. Constraint on Absolute Accuracy of Metacomprehension Assessments: The Anchoring and Adjustment Model vs. the Standards Model

    Science.gov (United States)

    Kwon, Heekyung

    2011-01-01

    The objective of this study is to provide a systematic account of three typical phenomena surrounding absolute accuracy of metacomprehension assessments: (1) the absolute accuracy of predictions is typically quite low; (2) there exist individual differences in absolute accuracy of predictions as a function of reading skill; and (3) postdictions…

  4. Systematization of accuracy indices variance when modelling the forming external cylindrical turning process

    Science.gov (United States)

    Balabanov, I. P.; Simonova, L. A.; Balabanova, O. N.

    2015-06-01

    The article considers the problem of accuracy deviation systematization for external cylindrical turning, proposed a hierarchical approach to the evaluation of these deviations, an approach to the analysis of nesting accuracy metrics, as well as, the common scheme of identification of deviations of the accuracy metrics for party billets in external machining were proposed.

  5. Accuracy of structure-based sequence alignment of automatic methods

    Directory of Open Access Journals (Sweden)

    Lee Byungkook

    2007-09-01

    Full Text Available Abstract Background Accurate sequence alignments are essential for homology searches and for building three-dimensional structural models of proteins. Since structure is better conserved than sequence, structure alignments have been used to guide sequence alignments and are commonly used as the gold standard for sequence alignment evaluation. Nonetheless, as far as we know, there is no report of a systematic evaluation of pairwise structure alignment programs in terms of the sequence alignment accuracy. Results In this study, we evaluate CE, DaliLite, FAST, LOCK2, MATRAS, SHEBA and VAST in terms of the accuracy of the sequence alignments they produce, using sequence alignments from NCBI's human-curated Conserved Domain Database (CDD as the standard of truth. We find that 4 to 9% of the residues on average are either not aligned or aligned with more than 8 residues of shift error and that an additional 6 to 14% of residues on average are misaligned by 1–8 residues, depending on the program and the data set used. The fraction of correctly aligned residues generally decreases as the sequence similarity decreases or as the RMSD between the Cα positions of the two structures increases. It varies significantly across CDD superfamilies whether shift error is allowed or not. Also, alignments with different shift errors occur between proteins within the same CDD superfamily, leading to inconsistent alignments between superfamily members. In general, residue pairs that are more than 3.0 Å apart in the reference alignment are heavily (>= 25% on average misaligned in the test alignments. In addition, each method shows a different pattern of relative weaknesses for different SCOP classes. CE gives relatively poor results for β-sheet-containing structures (all-β, α/β, and α+β classes, DaliLite for "others" class where all but the major four classes are combined, and LOCK2 and VAST for all-β and "others" classes. Conclusion When the sequence

  6. Accuracy Potential and Applications of MIDAS Aerial Oblique Camera System

    Science.gov (United States)

    Madani, M.

    2012-07-01

    Airborne oblique cameras such as Fairchild T-3A were initially used for military reconnaissance in 30s. A modern professional digital oblique camera such as MIDAS (Multi-camera Integrated Digital Acquisition System) is used to generate lifelike three dimensional to the users for visualizations, GIS applications, architectural modeling, city modeling, games, simulators, etc. Oblique imagery provide the best vantage for accessing and reviewing changes to the local government tax base, property valuation assessment, buying & selling of residential/commercial for better decisions in a more timely manner. Oblique imagery is also used for infrastructure monitoring making sure safe operations of transportation, utilities, and facilities. Sanborn Mapping Company acquired one MIDAS from TrackAir in 2011. This system consists of four tilted (45 degrees) cameras and one vertical camera connected to a dedicated data acquisition computer system. The 5 digital cameras are based on the Canon EOS 1DS Mark3 with Zeiss lenses. The CCD size is 5,616 by 3,744 (21 MPixels) with the pixel size of 6.4 microns. Multiple flights using different camera configurations (nadir/oblique (28 mm/50 mm) and (50 mm/50 mm)) were flown over downtown Colorado Springs, Colorado. Boresight fights for 28 mm nadir camera were flown at 600 m and 1,200 m and for 50 mm nadir camera at 750 m and 1500 m. Cameras were calibrated by using a 3D cage and multiple convergent images utilizing Australis model. In this paper, the MIDAS system is described, a number of real data sets collected during the aforementioned flights are presented together with their associated flight configurations, data processing workflow, system calibration and quality control workflows are highlighted and the achievable accuracy is presented in some detail. This study revealed that the expected accuracy of about 1 to 1.5 GSD (Ground Sample Distance) for planimetry and about 2 to 2.5 GSD for vertical can be achieved. Remaining systematic

  7. Accuracy of computed tomography in nodal staging of coloncancer patients

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    false negative rate (12%),compared to the surgeon review at 67% accuracy and31% false negative rate and the outside radiology reviewat 61% accuracy and 46% false negative rate.CONCLUSION: CT LN staging of colon cancer has moderateaccuracy, with administration of NCT based on CTpotentially resulting in overtreatment. Active search forLN+ may improve sensitivity at the cost of specificity.

  8. Self-Knowledge Dim-Out: Stress Impairs Metacognitive Accuracy

    Science.gov (United States)

    Reyes, Gabriel; Silva, Jaime R.; Jaramillo, Karina; Rehbein, Lucio; Sackur, Jérôme

    2015-01-01

    Modulation of frontal lobes activity is believed to be an important pathway trough which the hypothalamic-pituitary-adrenal (HPA) axis stress response impacts cognitive and emotional functioning. Here, we investigate the effects of stress on metacognition, which is the ability to monitor and control one's own cognition. As the frontal lobes have been shown to play a critical role in metacognition, we predicted that under activation of the HPA axis, participants should be less accurate in the assessment of their own performances in a perceptual decision task, irrespective of the effect of stress on the first order perceptual decision itself. To test this prediction, we constituted three groups of high, medium and low stress responders based on cortisol concentration in saliva in response to a standardized psycho-social stress challenge (the Trier Social Stress Test). We then assessed the accuracy of participants' confidence judgments in a visual discrimination task. As predicted, we found that high biological reactivity to stress correlates with lower sensitivity in metacognition. In sum, participants under stress know less when they know and when they do not know. PMID:26252222

  9. Dosimetric accuracy of tomotherapy dose calculation in thorax lesions

    Directory of Open Access Journals (Sweden)

    Mangili Paola

    2011-02-01

    Full Text Available Abstract Background To analyse limits and capabilities in dose calculation of collapsed-cone-convolution (CCC algorithm implemented in helical tomotherapy (HT treatment planning system for thorax lesions. Methods The agreement between measured and calculated dose was verified both in homogeneous (Cheese Phantom and in a custom-made inhomogeneous phantom. The inhomogeneous phantom was employed to mimic a patient's thorax region with lung density encountered in extreme cases and acrylic inserts of various dimensions and positions inside the lung cavity. For both phantoms, different lung treatment plans (single or multiple metastases and targets in the mediastinum using HT technique were simulated and verified. Point and planar dose measurements, both with radiographic extended-dose-range (EDR2 and radiochromic external-beam-therapy (EBT2 films, were performed. Absolute point dose measurements, dose profile comparisons and quantitative analysis of gamma function distributions were analyzed. Results An excellent agreement between measured and calculated dose distributions was found in homogeneous media, both for point and planar dose measurements. Absolute dose deviations Conclusions Very acceptable accuracy was found for complex lung treatment plans calculated with CCC algorithm implemented in the tomotherapy TPS even in the heterogeneous phantom with very low lung-density.

  10. Accuracy Improvement for Predicting Parkinson’s Disease Progression

    Science.gov (United States)

    Nilashi, Mehrbakhsh; Ibrahim, Othman; Ahani, Ali

    2016-01-01

    Parkinson’s disease (PD) is a member of a larger group of neuromotor diseases marked by the progressive death of dopamineproducing cells in the brain. Providing computational tools for Parkinson disease using a set of data that contains medical information is very desirable for alleviating the symptoms that can help the amount of people who want to discover the risk of disease at an early stage. This paper proposes a new hybrid intelligent system for the prediction of PD progression using noise removal, clustering and prediction methods. Principal Component Analysis (PCA) and Expectation Maximization (EM) are respectively employed to address the multi-collinearity problems in the experimental datasets and clustering the data. We then apply Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Regression (SVR) for prediction of PD progression. Experimental results on public Parkinson’s datasets show that the proposed method remarkably improves the accuracy of prediction of PD progression. The hybrid intelligent system can assist medical practitioners in the healthcare practice for early detection of Parkinson disease. PMID:27686748

  11. Classification Accuracy of Sequentially Administered WAIS-IV Short Forms.

    Science.gov (United States)

    Ryan, Joseph J; Kreiner, David S; Gontkovsky, Samuel T; Glass Umfleet, Laura

    2015-01-01

    A Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) short form (SF) may be effective for ruling out subnormal intelligence. To create a useful SF, subtest administration should follow the order prescribed in the manual and, depending upon individual performance, be terminated after completion of 2, 3, 4, or 5 subtests. One hundred and twenty-two patients completed the WAIS-IV. In two analyses, Full-Scale IQs (FSIQs) ≤69 and ≤79 were classified as impairment. Classification accuracy statistics indicated that all SFs using both cutoff scores exceeded the base rate (i.e., 14% and 34%) of subnormal intelligence, with hit rates ranging from 84% to 95%. The FSIQ cutoff of ≤69 had poor sensitivity for detecting impaired intellectual functioning with the 2-, 3-, 4-, and 5-subtest SFs; specificity, positive predictive value (PPV), and negative predictive value (NPV) were excellent for each SF. With the FSIQ cutoff of ≤79, sensitivity was strong to excellent for the 3-, 4-, and 5-subtest SFs as were specificity, PPV, and NPV.

  12. Diagnostic Accuracy of Urinary Cytokeratin 19 Fragment for Endometriosis

    Science.gov (United States)

    Savaris, R. F.; Ali, S.; Brophy, S.; Tomazic-Allen, S.; Chwalisz, K.

    2015-01-01

    Endometriosis affects up to 10% of women of reproductive age and 176 million women worldwide. The prevalence in women with infertility is between 30% and 50% but may be higher in women with pelvic pain, interstitial cystitis, or irritable bowel syndrome. Cytokeratin 19 has been suggested as a potential biomarker in urine for the diagnosis of this condition. The objective of this study was to prospectively determine the accuracy and the performance of a urinary cytokeratin 19 (uCYFRA 21-1) test for diagnosing endometriosis. Ninety-eight consecutive women who underwent laparoscopy had a urinary sample obtained before surgery and were included in the study. Endometriosis was diagnosed by laparoscopy and pathology in 64.3% (63 of 98 women). The estimates and 95% confidence intervals for sensitivity, specificity, positive and negative predictive values, and likelihood ratios were 11.1% (4.5%-21.5%), 94.3% (80.8%-99.3%), 77.7% (39.9-97.1), 37% (27-47.9), 1.94 (0.43-8.86), and 0.94 (0.84-1.06), respectively. Despite the high specificity, the uCYFRA 21-1 test has limited value for clinical practice to discriminate between women with and without endometriosis. PMID:25296695

  13. Do you really understand? Achieving accuracy in interracial relationships.

    Science.gov (United States)

    Holoien, Deborah Son; Bergsieker, Hilary B; Shelton, J Nicole; Alegre, Jan Marie

    2015-01-01

    Accurately perceiving whether interaction partners feel understood is important for developing intimate relationships and maintaining smooth interpersonal exchanges. During interracial interactions, when are Whites and racial minorities likely to accurately perceive how understood cross-race partners feel? We propose that participant race, desire to affiliate, and racial salience moderate accuracy in interracial interactions. Examination of cross-race roommates (Study 1) and interracial interactions with strangers (Study 2) revealed that when race is salient, Whites higher in desire to affiliate with racial minorities failed to accurately perceive the extent to which racial minority partners felt understood. Thus, although the desire to affiliate may appear beneficial, it may interfere with Whites' ability to accurately perceive how understood racial minorities feel. By contrast, racial minorities higher in desire to affiliate with Whites accurately perceived how understood White partners felt. Furthermore, participants' overestimation of how well they understood partners correlated negatively with partners' reports of relationship quality. Collectively, these findings indicate that racial salience and desire to affiliate moderate accurate perceptions of cross-race partners-even in the context of sustained interracial relationships-yielding divergent outcomes for Whites and racial minorities. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  14. Accuracy of seven vapour intrusion algorithms for VOC in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Provoost, Jeroen; Bronders, Jan; Seuntjens, Piet [Flemish Inst. for Technological Research (VITO), Mol (Belgium); Reijnders, Lucas [Dept. of Science, Open Univ. Netherlands (OU NL), Heerlen (Netherlands); Swartjes, Frank; Lijzen, Johannes [National Inst. for Public Health and the Environment (RIVM), Bilthoven (Netherlands)

    2009-02-15

    During the last decade, soil contamination with volatile organic contaminants (VOC) received special attention because of their potential to cause indoor air problems. Moreover, research has shown that people spend 64% to 94% of there time indoors; therefore, the indoor air quality is of a primary importance for exposure to VOC. Human health risks to VOC-in cases of soil contamination-are often dominated by the exposure route 'inhalation of indoor air'. Exposure is often a result of vapour transport from the soil or groundwater to the indoor air of the building. Within human health risk assessments, a variety of algorithms are available that calculate transfer of soil gas to the indoor air. These algorithms suffer from a relatively high uncertainty due to a lack of representation of spatial and temporal variability. For such an application, these algorithms need to be further verified empirically against field observations so that they can be sufficiently reliable for regulatory purposes. This paper presents the accuracy for seven algorithms by using observed and predicted soil and indoor air concentrations from three sites, where the groundwater had been contaminated with aromatic and chlorinated VOC. (orig.)

  15. Sensitivity analysis for high accuracy proximity effect correction

    Science.gov (United States)

    Thrun, Xaver; Browning, Clyde; Choi, Kang-Hoon; Figueiro, Thiago; Hohle, Christoph; Saib, Mohamed; Schiavone, Patrick; Bartha, Johann W.

    2015-10-01

    A sensitivity analysis (SA) algorithm was developed and tested to comprehend the influences of different test pattern sets on the calibration of a point spread function (PSF) model with complementary approaches. Variance-based SA is the method of choice. It allows attributing the variance of the output of a model to the sum of variance of each input of the model and their correlated factors.1 The objective of this development is increasing the accuracy of the resolved PSF model in the complementary technique through the optimization of test pattern sets. Inscale® from Aselta Nanographics is used to prepare the various pattern sets and to check the consequences of development. Fraunhofer IPMS-CNT exposed the prepared data and observed those to visualize the link of sensitivities between the PSF parameters and the test pattern. First, the SA can assess the influence of test pattern sets for the determination of PSF parameters, such as which PSF parameter is affected on the employments of certain pattern. Secondly, throughout the evaluation, the SA enhances the precision of PSF through the optimization of test patterns. Finally, the developed algorithm is able to appraise what ranges of proximity effect correction is crucial on which portion of a real application pattern in the electron beam exposure.

  16. Diagnostic accuracy of nodular gastritis for H. pylori infection

    Science.gov (United States)

    Romero-Flores, Juan L; Fernandez-Rivero, Justo A; Marroquín-Fabian, Erika; Téllez-Ávila, Félix I; Sánchez-Jiménez, Beatriz A; Juárez-Hernández, Eva; Uribe, Misael; Chávez-Tapia, Norberto C

    2017-01-01

    Background The term nodular is not included in the Sydney classification and there is no widely accepted histopathological definition. It has been proposed that the presence of antral nodularity could predict Helicobacter pylori (H. pylori) infection. The aim of this study was to determine the diagnostic accuracy of nodular gastritis (NG) for H. pylori infection after a rigorous standardization process, and to describe the associated histopathological characteristics. Materials and methods Endoscopic images of patients submitted to endoscopy with biopsy sampling were included. Endoscopic images were distributed among six endoscopists. The analysis was performed sequentially in three rounds: the first round assessed the interobserver variability, the second evaluated the intraobserver variability, and the third calculated the interobserver variability after training. A correlation analysis between endoscopic and histopathological findings was performed. Results A total of 917 studies were included. In the first analysis of interobserver variability, a poor kappa value (0.078) was obtained. The second evaluation yielded good intraobserver variability, with kappa values of 0.62–0.86. The evaluation of interobserver variability after training revealed an improvement in the kappa value of 0.42. A correlation was found between endoscopic images and histopathological reports. Conclusion There was a strong correlation between NG and H. pylori, but only after rigorous evaluation. The use of the term NG requires extensive standardization before it can be used clinically. PMID:28031716

  17. Nanometer accuracy with continuous scans at the ALBA-NOM

    Science.gov (United States)

    Nicolas, Josep; Pedreira, Pablo; Å ics, Igors; Ramírez, Claudio; Campos, Juan

    2016-09-01

    We present the continuous scan operation of the ALBA-NOM as a working mode that allows obtaining low noise in short time, as well as high accuracy measurements. In the traditional step-scan operation, the position of the probe beam is kept fixed while many data points of autocollimator are averaged for noise reduction. This operation mode is very safe, as one has a perfect correspondence between mirror position and measured angle, but it is time inefficient, as it disregards all the data values acquired during motion, and basically averages data values taken under identical conditions. On the other hand, continuous scan is less safe in terms of correspondence between mirror position and slope, especially for NOM systems for which the autocollimator does not accept an electronic trigger. Nevertheless, it is possible to perform independent acquisitions of the autocollimator and of the linear stage data during a scan, and synchronize signals a posteriori. This solves the main problem of continuous scan with a NOM. Continuous scan operation for performing measurements is very efficient for noise reduction per unit time, as it allows integrating every single data value taken by the autocollimator. In addition, it opens the possibility of introducing pitch variations of the mirror between scans. This allows obtaining many independent datasets that can be combined using error suppression techniques to reduce not just noise but systematic errors too. In this paper we report the methods and the main results.

  18. 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.

  19. 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. PMID:27625628

  20. Accuracy of diagnostic imaging in nephroblastoma before preoperative chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Rieden, K. [Radiologische Klinik, Abt. Klinische Radiologie, Heidelberg (Germany); Weirich, A. [Kinderklinik, Univ. of Heidelberg (Germany); Troeger, J. [Radiologische Klinik, Abt. Paediatrische Radiologie, Univ. of Heidelberg (Germany); Gamroth, A.H. [Deutsches Krebsforschungszentrum, Heidelberg (Germany); Raschke, K. [Radiologische Klinik, Abt. Paediatrische Radiologie, Univ. of Heidelberg (Germany); Ludwig, R. [Kinderklinik, Univ. of Heidelberg (Germany)

    1993-04-01

    From July 1988 to February 1991, 130 children with the tentative diagnosis of nephroblastoma were treated preoperatively. The initial diagnostic images (excretory urography, ultrasound, CT, MRI) have been analysed both prospectively and retrospectively and the findings correlated with the intraoperative and histological results. Of the preoperatively treated patients 93.8% had a Wilms` tumour or one of its variants. Five patients had a different malignant tumour and 3 patients, i.e. 2.3% of those preoperatively treated or 1.6% of all registered patients, had benign tumours of the kidney. Wilms` tumour generally presented as a well-defined mass with an inhomogeneous morphology on CT. On ultrasound only 24% of the tumours were homogeneous. Intratumoral haemorrhage and cystic areas occurred frequently; calcifications were rare (8%). With regard to caval involvement only ultrasound and MRI enabled the correct diagnosis, while CT could not differentiate compressions from invasion. The pretherapeutic diagnostic imaging was of sufficient accuracy to start preoperative chemotherapy without diagnostic biopsy. (orig.)