Science.gov

Sample records for achieve chemical accuracy

  1. Achieving Climate Change Absolute Accuracy in Orbit

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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. PMID:27329206

  3. Quantum mechanical calculations to chemical accuracy

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  4. Approaching chemical accuracy with quantum Monte Carlo.

    PubMed

    Petruzielo, F R; Toulouse, Julien; Umrigar, C J

    2012-03-28

    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. PMID:22462844

  5. Achieving seventh-order amplitude accuracy in leapfrog integrations

    NASA Astrophysics Data System (ADS)

    Williams, Paul

    2015-04-01

    The leapfrog time-stepping scheme is commonly used in general circulation models of weather and climate. The Robert-Asselin filter is used in conjunction with it, to damp the computational mode. Although the leapfrog scheme makes no amplitude errors when integrating linear oscillations, the Robert-Asselin filter introduces first-order amplitude errors. The RAW filter, which was recently proposed as an improvement, eliminates the first-order amplitude errors and yields third-order amplitude accuracy. This development has been shown to significantly increase the skill of medium-range weather forecasts. However, it has not previously been shown how to further improve the accuracy by eliminating the third- and higher-order amplitude errors. This presentation will show that leapfrogging over a suitably weighted blend of the filtered and unfiltered tendencies eliminates the third-order amplitude errors and yields fifth-order amplitude accuracy. It will also show that the use of a more discriminating (1,-4,6,-4,1) filter instead of a (1,-2,1) filter eliminates the fifth-order amplitude errors and yields seventh-order amplitude accuracy. Other related schemes are obtained by varying the values of the filter parameters, and it is found that several combinations offer an appealing compromise of stability and accuracy. The proposed new schemes are shown to yield substantial forecast improvements in a medium-complexity atmospheric general circulation model. They appear to be attractive alternatives to the filtered leapfrog schemes currently used in many weather and climate models. Reference Williams PD (2013) Achieving seventh-order amplitude accuracy in leapfrog integrations. Monthly Weather Review 141(9), pp 3037-3051. DOI: 10.1175/MWR-D-12-00303.1

  6. Use of Chemical Inventory Accuracy Measurements as Leading Indicators

    SciTech Connect

    Quigley, David; Freshwater, David; Alnajjar, Mikhail S.; Siegel, Dina; Kuntamukkula, Murty; Simmons, Fred

    2012-05-15

    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: (1) what properties make leading indicators effective, (2) how chemical inventories can be used as a leading indicator, (3) how chemical inventory accuracy can be measured, what levels of accuracies should realistically be expected in a healthy system, and (4) what a subpar inventory accuracy measurement portends.

  7. USE OF CHEMICAL INVENTORY ACCURACY MEASUREMENTS AS LEADING INDICATORS

    SciTech Connect

    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.

  8. Achieving Seventh-Order Amplitude Accuracy in Leapfrog Integrations

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2014-12-01

    The leapfrog time-stepping scheme is commonly used in general circulation models of the atmosphere and ocean. The Robert-Asselin filter is used in conjunction with it, to damp the computational mode. Although the leapfrog scheme makes no amplitude errors when integrating linear oscillations, the Robert-Asselin filter introduces first-order amplitude errors. The RAW filter, which was recently proposed as an improvement, eliminates the first-order amplitude errors and yields third-order amplitude accuracy. This development has been shown to significantly increase the skill of medium-range weather forecasts. However, it has not previously been shown how to further improve the accuracy by eliminating the third- and higher-order amplitude errors. This presentation will show that leapfrogging over a suitably weighted blend of the filtered and unfiltered tendencies eliminates the third-order amplitude errors and yields fifth-order amplitude accuracy. It will also show that the use of a more discriminating (1, -4, 6, -4, 1) filter instead of a (1, -2, 1) filter eliminates the fifth-order amplitude errors and yields seventh-order amplitude accuracy. Other related schemes are obtained by varying the values of the filter parameters, and it is found that several combinations offer an appealing compromise of stability and accuracy. The proposed new schemes are shown to yield substantial forecast improvements in a medium-complexity atmospheric general circulation model. They appear to be attractive alternatives to the filtered leapfrog schemes currently used in many weather and climate models.

  9. Is accuracy of serum free light chain measurement achievable?

    PubMed

    Jacobs, Joannes F M; Tate, Jillian R; Merlini, Giampaolo

    2016-06-01

    The serum free light chain (FLC) assay has proven to be an important complementary test in the management of patients with monoclonal gammopathies. The serum FLC assay has value for patients with plasma cell disorders in the context of screening and diagnosis, prognostic stratification, and quantitative monitoring. Nonetheless, serum FLC measurements have analytical limitations which give rise to differences in FLC reporting depending on which FLC assay and analytical platform is used. As the FLC measurements are incorporated in the International Myeloma Working Group guidelines for the evaluation and management of plasma cell dyscrasias, this may directly affect clinical decisions. As new certified methods for serum FLC assays emerge, the need to harmonise patient FLC results becomes increasingly important. In this opinion paper we provide an overview of the current lack of accuracy and harmonisation in serum FLC measurements. The clinical consequence of non-harmonized FLC measurements is that an individual patient may or may not meet certain diagnostic, prognostic, or response criteria, depending on which FLC assay and platform is used. We further discuss whether standardisation of serum FLC measurements is feasible and provide an overview of the steps needed to be taken towards harmonisation of FLC measurements. PMID:26641970

  10. Accuracy required and achievable in radiotherapy dosimetry: have modern technology and techniques changed our views?

    NASA Astrophysics Data System (ADS)

    Thwaites, David

    2013-06-01

    In this review of the accuracy required and achievable in radiotherapy dosimetry, older approaches and evidence-based estimates for 3DCRT have been reprised, summarising and drawing together the author's earlier evaluations where still relevant. Available evidence for IMRT uncertainties has been reviewed, selecting information from tolerances, QA, verification measurements, in vivo dosimetry and dose delivery audits, to consider whether achievable uncertainties increase or decrease for current advanced treatments and practice. Overall there is some evidence that they tend to increase, but that similar levels should be achievable. Thus it is concluded that those earlier estimates of achievable dosimetric accuracy are still applicable, despite the changes and advances in technology and techniques. The one exception is where there is significant lung involvement, where it is likely that uncertainties have now improved due to widespread use of more accurate heterogeneity models. Geometric uncertainties have improved with the wide availability of IGRT.

  11. The Influence of Overt Practice, Achievement Level, and Explanatory Style on Calibration Accuracy and Performance

    ERIC Educational Resources Information Center

    Bol, Linda; Hacker, Douglas J.; O'Shea, Patrick; Allen, Dwight

    2005-01-01

    The authors measured the influence of overt calibration practice, achievement level, and explanatory style on calibration accuracy and exam performance. Students (N = 356) were randomly assigned to either an overt practice or no-practice condition. Students in the overt practice condition made predictions and postdictions about their performance…

  12. Chemical accuracy from quantum Monte Carlo for the benzene dimer

    SciTech Connect

    Azadi, Sam; Cohen, R. E.

    2015-09-14

    We report an accurate study of interactions between benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory using different van der Waals functionals. In our quantum Monte Carlo (QMC) calculations, we use accurate correlated trial wave functions including three-body Jastrow factors and backflow transformations. We consider two benzene molecules in the parallel displaced geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of −2.3(4) and −2.7(3) kcal/mol, respectively. The best estimate of the coupled-cluster theory through perturbative triplets/complete basis set limit is −2.65(2) kcal/mol [Miliordos et al., J. Phys. Chem. A 118, 7568 (2014)]. Our results indicate that QMC methods give chemical accuracy for weakly bound van der Waals molecular interactions, comparable to results from the best quantum chemistry methods.

  13. Chemical accuracy from quantum Monte Carlo for the benzene dimer.

    PubMed

    Azadi, Sam; Cohen, R E

    2015-09-14

    We report an accurate study of interactions between benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory using different van der Waals functionals. In our quantum Monte Carlo (QMC) calculations, we use accurate correlated trial wave functions including three-body Jastrow factors and backflow transformations. We consider two benzene molecules in the parallel displaced geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of -2.3(4) and -2.7(3) kcal/mol, respectively. The best estimate of the coupled-cluster theory through perturbative triplets/complete basis set limit is -2.65(2) kcal/mol [Miliordos et al., J. Phys. Chem. A 118, 7568 (2014)]. Our results indicate that QMC methods give chemical accuracy for weakly bound van der Waals molecular interactions, comparable to results from the best quantum chemistry methods. PMID:26374029

  14. Concept Maps about Chemical Equilibrium and Students' Achievement Scores.

    ERIC Educational Resources Information Center

    Wilson, Jan

    1996-01-01

    Examines relationships between structural characteristics of students' concept maps about chemical equilibrium and independent measures of their achievement in chemistry. Results indicate significant relationships between multidimensional scaling coordinates and test scores of recall of knowledge and its application and also reveal structural…

  15. THE IMPORTANCE OF SPATIAL ACCURACY FOR CHEMICAL INFORMATION MANAGEMENT

    EPA Science Inventory

    Information about chemicals can be critical to making timely decisions. The results of these decisions may not be realized for many years. In order to increase the value of chemical information and to create and utilize meaningful environmental models, the Environmental Prote...

  16. Network representations of knowledge about chemical equilibrium: Variations with achievement

    NASA Astrophysics Data System (ADS)

    Wilson, Janice M.

    This study examined variation in the organization of domain-specific knowledge by 50 Year-12 chemistry students and 4 chemistry teachers. The study used nonmetric multidimensional scaling (MDS) and the Pathfinder network-generating algorithm to investigate individual and group differences in student concepts maps about chemical equilibrium. MDS was used to represent the individual maps in two-dimensional space, based on the presence or absence of paired propositional links. The resulting separation between maps reflected degree of hierarchical structure, but also reflected independent measures of student achievement. Pathfinder was then used to produce semantic networks from pooled data from high and low achievement groups using proximity matrices derived from the frequencies of paired concepts. The network constructed from maps of higher achievers (coherence measure = 0.18, linked pairs = 294, and number of subjects = 32) showed greater coherence, more concordance in specific paired links, more important specific conceptual relationships, and greater hierarchical organization than did the network constructed from maps of lower achievers (coherence measure = 0.12, linked pairs = 552, and number of subjects = 22). These differences are interpreted in terms of qualitative variation in knowledge organization by two groups of individuals with different levels of relative expertise (as reflected in achievement scores) concerning the topic of chemical equilibrium. The results suggest that the technique of transforming paired links in concept maps into proximity matrices for input to multivariate analyses provides a suitable methodology for comparing and documenting changes in the organization and structure of conceptual knowledge within and between individual students.

  17. Concept maps about chemical equilibrium and students' achievement scores

    NASA Astrophysics Data System (ADS)

    Wilson, Jan

    1996-06-01

    The purpose of this study was to examine relationships between structural characteristics of students' concept maps about chemical equilibrium and independent measures of their achievement in chemistry. Fifty students in 1991 and seventy students in 1992 completed a concept-mapping task using twenty-four specified concepts. Using similarities in concept map structure, based on the presence or absence of linked pairs of concepts, non-metric multidimensional scaling (MDS) was used to plot the location of the concept maps in coordinate space. The distribution of maps was based on differences in their structure, but also reflected levels of student achievement on independent tests. The relationship between the coordinate location of each student's maps and his or her test scores on independent chemistry achievement tests was sought by canonical correlation analysis of the 1991 data set. This revealed significant relationships between the MDS coordinates and test scores of recall of knowledge and its application. Multiple regression analysis of sixty-one students' maps from the 1992 data set against their percentile rank scores on a national chemistry quiz revealed significant relationships. The results are interpreted as revealing structural differences in conceptual organisation about chemical equilibrium among students with different levels of achievement and thus relative expertise in the domain. The significant relationship between map structure and cognitive process scores in chemistry also supports the view that the organisation of declarative knowledge influences its accessibility in cognitive tasks.

  18. Accuracy of Self-Reported College GPA: Gender-Moderated Differences by Achievement Level and Academic Self-Efficacy

    ERIC Educational Resources Information Center

    Caskie, Grace I. L.; Sutton, MaryAnn C.; Eckhardt, Amanda G.

    2014-01-01

    Assessments of college academic achievement tend to rely on self-reported GPA values, yet evidence is limited regarding the accuracy of those values. With a sample of 194 undergraduate college students, the present study examined whether accuracy of self-reported GPA differed based on level of academic performance or level of academic…

  19. Phase noise in pulsed Doppler lidar and limitations on achievable single-shot velocity accuracy

    NASA Technical Reports Server (NTRS)

    Mcnicholl, P.; Alejandro, S.

    1992-01-01

    The smaller sampling volumes afforded by Doppler lidars compared to radars allows for spatial resolutions at and below some sheer and turbulence wind structure scale sizes. This has brought new emphasis on achieving the optimum product of wind velocity and range resolutions. Several recent studies have considered the effects of amplitude noise, reduction algorithms, and possible hardware related signal artifacts on obtainable velocity accuracy. We discuss here the limitation on this accuracy resulting from the incoherent nature and finite temporal extent of backscatter from aerosols. For a lidar return from a hard (or slab) target, the phase of the intermediate frequency (IF) signal is random and the total return energy fluctuates from shot to shot due to speckle; however, the offset from the transmitted frequency is determinable with an accuracy subject only to instrumental effects and the signal to noise ratio (SNR), the noise being determined by the LO power in the shot noise limited regime. This is not the case for a return from a media extending over a range on the order of or greater than the spatial extent of the transmitted pulse, such as from atmospheric aerosols. In this case, the phase of the IF signal will exhibit a temporal random walk like behavior. It will be uncorrelated over times greater than the pulse duration as the transmitted pulse samples non-overlapping volumes of scattering centers. Frequency analysis of the IF signal in a window similar to the transmitted pulse envelope will therefore show shot-to-shot frequency deviations on the order of the inverse pulse duration reflecting the random phase rate variations. Like speckle, these deviations arise from the incoherent nature of the scattering process and diminish if the IF signal is averaged over times greater than a single range resolution cell (here the pulse duration). Apart from limiting the high SNR performance of a Doppler lidar, this shot-to-shot variance in velocity estimates has a

  20. Stellar chemical abundances: in pursuit of the highest achievable precision

    SciTech Connect

    Bedell, Megan; Bean, Jacob L.; Meléndez, Jorge; Leite, Paulo; Asplund, Martin

    2014-11-01

    The achievable level of precision on photospheric abundances of stars is a major limiting factor on investigations of exoplanet host star characteristics, the chemical histories of star clusters, and the evolution of the Milky Way and other galaxies. While model-induced errors can be minimized through the differential analysis of spectrally similar stars, the maximum achievable precision of this technique has been debated. As a test, we derive differential abundances of 19 elements from high-quality asteroid-reflected solar spectra taken using a variety of instruments and conditions. We treat the solar spectra as being from unknown stars and use the resulting differential abundances, which are expected to be zero, as a diagnostic of the error in our measurements. Our results indicate that the relative resolution of the target and reference spectra is a major consideration, with use of different instruments to obtain the two spectra leading to errors up to 0.04 dex. Use of the same instrument at different epochs for the two spectra has a much smaller effect (∼0.007 dex). The asteroid used to obtain the solar standard also has a negligible effect (∼0.006 dex). Assuming that systematic errors from the stellar model atmospheres have been minimized, as in the case of solar twins, we confirm that differential chemical abundances can be obtained at sub-0.01 dex precision with due care in the observations, data reduction, and abundance analysis.

  1. The Effects of Individual or Group Guidelines on the Calibration Accuracy and Achievement of High School Biology Students

    ERIC Educational Resources Information Center

    Bol, Linda; Hacker, Douglas J.; Walck, Camilla C.; Nunnery, John A.

    2012-01-01

    A 2 x 2 factorial design was employed in a quasi-experiment to investigate the effects of guidelines in group or individual settings on the calibration accuracy and achievement of 82 high school biology students. Significant main effects indicated that calibration practice with guidelines and practice in group settings increased prediction and…

  2. Accuracy of Teachers' Judgments of Students' Academic Achievement: A Meta-Analysis

    ERIC Educational Resources Information Center

    Sudkamp, Anna; Kaiser, Johanna; Moller, Jens

    2012-01-01

    This meta-analysis summarizes empirical results on the correspondence between teachers' judgments of students' academic achievement and students' actual academic achievement. The article further investigates theoretically and methodologically relevant moderators of the correlation between the two measures. Overall, 75 studies reporting…

  3. New integration techniques for chemical kinetic rate equations. II - Accuracy comparison

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, K.

    1986-01-01

    A comparison of the accuracy of several techniques recently developed for solving stiff differential equations is presented. The techniques examined include two general purpose codes EEPISODE and LSODE developed for an arbitrary system of ordinary differential equations, and three specialized codes CHEMEQ, CREKID, and GCKP84 developed specifically to solve chemical kinetic rate equations. The accuracy comparisons are made by applying these solution procedures to two practical combustion kinetics problems. Both problems describe adiabatic, homogeneous, gas phase chemical reactions at constant pressure, and include all three combustion regimes: induction heat release, and equilibration. The comparisons show that LSODE is the most efficient code - in the sense that it requires the least computational work to attain a specified accuracy level. An important finding is that an iterative solution of the algebraic enthalpy conservation equation for the temperature can be more accurate and efficient than computing the temperature by integrating its time derivative.

  4. New integration techniques for chemical kinetic rate equations. 2: Accuracy comparison

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, K.

    1985-01-01

    A comparison of the accuracy of several techniques recently developed for solving stiff differential equations is presented. The techniques examined include two general purpose codes EEPISODE and LSODE developed for an arbitrary system of ordinary differential equations, and three specialized codes CHEMEQ, CREKID, and GCKP84 developed specifically to solve chemical kinetic rate equations. The accuracy comparisons are made by applying these solution procedures to two practical combustion kinetics problems. Both problems describe adiabatic, homogeneous, gas phase chemical reactions at constant pressure, and include all three combustion regimes: induction, heat release, and equilibration. The comparisons show that LSODE is the most efficient code - in the sense that it requires the least computational work to attain a specified accuracy level. An important finding is that an iterative solution of the algebraic enthalpy conservation equation for the temperature can be more accurate and efficient than computing the temperature by integrating its time derivative.

  5. Design considerations for achieving high accuracy with the SHOALS bathymetric lidar system

    NASA Astrophysics Data System (ADS)

    Guenther, Gary C.; Thomas, Robert W. L.; LaRocque, Paul E.

    1996-11-01

    The ultimate accuracy of depths from an airborne laser hydrography system depends both on careful hardware design aimed at producing the best possible accuracy and precision of recorded data, along with insensitivity to environmental effects, and on post-flight data processing software which corrects for a number of unavoidable biases and provides for flexible operator interaction to handle special cases. The generic procedure for obtaining a depth from an airborne lidar pulse involves measurement of the time between the surface return and the bottom return. In practice, because both of these return times are biased due to a number of environmental and hardware effects, it is necessary to apply various correctors in order to obtain depth estimates which are sufficiently accurate to meet International Hydrographic Office standards. Potential false targets, also of both environmental and hardware origin, must be discriminated, and wave heights must be removed. It is important to have a depth confidence value matched to accuracy and to have warnings about or automatic deletion of pulses with questionable characteristics. Techniques, procedures, and algorithms developed for the SHOALS systems are detailed here.

  6. Novel FBG interrogation technique for achieving < 100 nɛ accuracies at remote distances > 70 km

    NASA Astrophysics Data System (ADS)

    Farrell, Tom; O'Connor, Peter; Levins, John; McDonald, David

    2005-06-01

    Due to the development of Fibre Bragg Grating sensors for the measurement of temperature, strain and pressure many markets can benefit from optical technology. These markets are the oil and gas industry, structural and civil engineering, rail and aerospace to name a few. The advantages of using optical sensing technology are that high accuracy measurements can be performed with a passive optical system. By running one fibre along the structure or down the well, multiple points along the fibre can be tested to measure strain, temperature and pressure. Of importance with these systems is the reach that can be obtained while maintaining accuracy. A major problem with long reach system is the back reflection due to SBS and Rayleigh scattering processes which reflect part of the laser light back into the receiver which affect the sensitivity of system. This paper shows a technique to enable a reach of >70km by using a tunable laser and receiver. Techniques for the suppression of receiver noise from SBS and Raleigh scattering are implemented. In addition polarisation dependence of the FBG is considered and results of techniques to limit the effect of polarisation at long and short reaches are shown.

  7. You are so beautiful... to me: seeing beyond biases and achieving accuracy in romantic relationships.

    PubMed

    Solomon, Brittany C; Vazire, Simine

    2014-09-01

    Do romantic partners see each other realistically, or do they have overly positive perceptions of each other? Research has shown that realism and positivity co-exist in romantic partners' perceptions (Boyes & Fletcher, 2007). The current study takes a novel approach to explaining this seemingly paradoxical effect when it comes to physical attractiveness--a highly evaluative trait that is especially relevant to romantic relationships. Specifically, we argue that people are aware that others do not see their partners as positively as they do. Using both mean differences and correlational approaches, we test the hypothesis that despite their own biased and idiosyncratic perceptions, people have 2 types of partner-knowledge: insight into how their partners see themselves (i.e., identity accuracy) and insight into how others see their partners (i.e., reputation accuracy). Our results suggest that romantic partners have some awareness of each other's identity and reputation for physical attractiveness, supporting theories that couple members' perceptions are driven by motives to fulfill both esteem- and epistemic-related needs (i.e., to see their partners positively and realistically). PMID:25133729

  8. Recent achievements in chemical studies of heaviest elements

    NASA Astrophysics Data System (ADS)

    Gäggeler, H. W.

    2011-09-01

    Discovery of heavy elements up to atomic number 118 at FLNR in Dubna has paved the way to also extend chemical knowledge to heavier members of the periodic table. Recent studies on the chemical properties of Cn and element 114 are summarized that have been performed at FLNR in Dubna using the fusion reactions 48Ca + 242/244Pu.

  9. On achieving sufficient dual station range accuracy for deep space navigation at zero declination

    NASA Technical Reports Server (NTRS)

    Siegel, H. L.; Christensen, C. S.; Green, D. W.; Winn, F. B.

    1977-01-01

    Since the Voyager Mission will encounter Saturn at a time when the planet will be nearly in the earth's equatorial plane, earth-based orbit determination will be more difficult than usual because of the so-called zero-declination singularity associated with conventional radiometric observations. Simulation studies show that in order to meet the required delivery accuracy at Saturn, a relative range measurement between the Goldstone and Canberra Deep Space Stations must be accurate to 4.5 times the square root of two meters. Topics discussed include the nature of error sources, the methodology and technology required for calibration, the verification process concerning the nearly simultaneous range capability, a description of the ranging system, and tracking strategy.

  10. Achieving sub-pixel geolocation accuracy in support of MODIS land science

    USGS Publications Warehouse

    Wolfe, R.E.; Nishihama, M.; Fleig, A.J.; Kuyper, J.A.; Roy, D.P.; Storey, J.C.; Patt, F.S.

    2002-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) was launched in December 1999 on the polar orbiting Terra spacecraft and since February 2000 has been acquiring daily global data in 36 spectral bands-29 with 1 km, five with 500 m, and two with 250 m nadir pixel dimensions. The Terra satellite has on-board exterior orientation (position and attitude) measurement systems designed to enable geolocation of MODIS data to approximately 150 m (1??) at nadir. A global network of ground control points is being used to determine biases and trends in the sensor orientation. Biases have been removed by updating models of the spacecraft and instrument orientation in the MODIS geolocation software several times since launch and have improved the MODIS geolocation to approximately 50 m (1??) at nadir. This paper overviews the geolocation approach, summarizes the first year of geolocation analysis, and overviews future work. The approach allows an operational characterization of the MODIS geolocation errors and enables individual MODIS observations to be geolocated to the sub-pixel accuracies required for terrestrial global change applications. ?? 2002 Elsevier Science Inc. All rights reserved.

  11. a Method to Achieve Large Volume, High Accuracy Photogrammetric Measurements Through the Use of AN Actively Deformable Sensor Mounting Platform

    NASA Astrophysics Data System (ADS)

    Sargeant, B.; Robson, S.; Szigeti, E.; Richardson, P.; El-Nounu, A.; Rafla, M.

    2016-06-01

    When using any optical measurement system one important factor to consider is the placement of the sensors in relation to the workpiece being measured. When making decisions on sensor placement compromises are necessary in selecting the best placement based on the shape and size of the object of interest and the desired resolution and accuracy. One such compromise is in the distance the sensors are placed from the measurement surface, where a smaller distance gives a higher spatial resolution and local accuracy and a greater distance reduces the number of measurements necessary to cover a large area reducing the build-up of errors between measurements and increasing global accuracy. This paper proposes a photogrammetric approach whereby a number of sensors on a continuously flexible mobile platform are used to obtain local measurements while the position of the sensors is determined by a 6DoF tracking solution and the results combined to give a single set of measurement data within a continuous global coordinate system. The ability of this approach to achieve both high accuracy measurement and give results over a large volume is then tested and areas of weakness to be improved upon are identified.

  12. Chemical Achievers: The Human Face of the Chemical Sciences (by Mary Ellen Bowden)

    NASA Astrophysics Data System (ADS)

    Kauffman, George B.

    1999-02-01

    Chemical Heritage Foundation: Philadelphia, PA, 1997. viii + 180 pp. 21.6 x 27.8 cm. ISBN 0-941901-15-1. Paper. 20.00 (10.00 for high school teachers who provide documentation). At a 1991 summer workshop sponsored by the Chemical Heritage Foundation and taught by Derek A. Davenport and William B. Jensen, high school and college teachers of introductory chemistry requested a source of pictorial material about famous chemical scientists suitable as a classroom aid. CHF responded by publishing this attractive, inexpensive paperback volume, which reflects the considerable research effort needed to locate appropriate images and to write the biographical essays. Printed on heavy, glossy paper and spiral bound to facilitate conversion to overhead transparencies, it contains 157 images from pictorial collections at CHF and many other institutions on two types of achievers: the historical "greats" most often referred to in introductory courses, and scientists who made contributions in areas of the chemical sciences that are of special relevance to modern life and the career choices students will make. The pictures are intended to provide the "human face" of the book's subtitle- "to point to the human beings who had the insights and made the major advances that [teachers] ask students to master." Thus, for example, Boyle's law becomes less cold and abstract if the student can connect it with the two portraits of the Irish scientist even if his face is topped with a wig. Marie Curie can be seen in the role of wife and mother as well as genius scientist in the photographs of her with her two daughters, one of whom also became a Nobel laureate. And students are reminded of the ubiquity of the contribution of the chemical scientists to all aspects of our everyday life by the stories and pictures of Wallace Hume Carothers' path to nylon, Percy Lavon Julian's work on hormones, and Charles F. Chandler and Rachel Carson's efforts to preserve the environment. In addition to portraits

  13. Clinical decision support systems for improving diagnostic accuracy and achieving precision medicine.

    PubMed

    Castaneda, Christian; Nalley, Kip; Mannion, Ciaran; Bhattacharyya, Pritish; Blake, Patrick; Pecora, Andrew; Goy, Andre; Suh, K Stephen

    2015-01-01

    As research laboratories and clinics collaborate to achieve precision medicine, both communities are required to understand mandated electronic health/medical record (EHR/EMR) initiatives that will be fully implemented in all clinics in the United States by 2015. Stakeholders will need to evaluate current record keeping practices and optimize and standardize methodologies to capture nearly all information in digital format. Collaborative efforts from academic and industry sectors are crucial to achieving higher efficacy in patient care while minimizing costs. Currently existing digitized data and information are present in multiple formats and are largely unstructured. In the absence of a universally accepted management system, departments and institutions continue to generate silos of information. As a result, invaluable and newly discovered knowledge is difficult to access. To accelerate biomedical research and reduce healthcare costs, clinical and bioinformatics systems must employ common data elements to create structured annotation forms enabling laboratories and clinics to capture sharable data in real time. Conversion of these datasets to knowable information should be a routine institutionalized process. New scientific knowledge and clinical discoveries can be shared via integrated knowledge environments defined by flexible data models and extensive use of standards, ontologies, vocabularies, and thesauri. In the clinical setting, aggregated knowledge must be displayed in user-friendly formats so that physicians, non-technical laboratory personnel, nurses, data/research coordinators, and end-users can enter data, access information, and understand the output. The effort to connect astronomical numbers of data points, including '-omics'-based molecular data, individual genome sequences, experimental data, patient clinical phenotypes, and follow-up data is a monumental task. Roadblocks to this vision of integration and interoperability include ethical, legal

  14. Can Chemical Mouthwash Agents Achieve Plaque/Gingivitis Control?

    PubMed

    Van der Weijden, Fridus A; Van der Sluijs, Eveline; Ciancio, Sebastian G; Slot, Dagmar E

    2015-10-01

    Also note that structured abstracts are not allowed per journal style: What is the effect of a mouthwash containing various active chemical ingredients on plaque control and managing gingivitis in adults based on evidence gathered from existing systematic reviews? The summarized evidence suggests that mouthwashes containing chlorhexidine(CHX) and essential oils (EO) had a large effect supported by a strong body of evidence. Also there was strong evidence for a moderate effect of cetylpyridinium chloride(CPC). Evidence suggests that a CHX mouthwash is the first choice, the most reliable alternative is EO. No difference between CHX and EO with respect to gingivitis was observed. PMID:26427569

  15. Frapid: achieving full automation of FRAP for chemical probe validation.

    PubMed

    Yapp, Clarence; Rogers, Catherine; Savitsky, Pavel; Philpott, Martin; Müller, Susanne

    2016-02-01

    Fluorescence Recovery After Photobleaching (FRAP) is an established method for validating chemical probes against the chromatin reading bromodomains, but so far requires constant human supervision. Here, we present Frapid, an automated open source code implementation of FRAP that fully handles cell identification through fuzzy logic analysis, drug dispensing with a custom-built fluid handler, image acquisition & analysis, and reporting. We successfully tested Frapid on 3 bromodomains as well as on spindlin1 (SPIN1), a methyl lysine binder, for the first time. PMID:26977352

  16. Frapid: achieving full automation of FRAP for chemical probe validation

    PubMed Central

    Yapp, Clarence; Rogers, Catherine; Savitsky, Pavel; Philpott, Martin; Müller, Susanne

    2016-01-01

    Fluorescence Recovery After Photobleaching (FRAP) is an established method for validating chemical probes against the chromatin reading bromodomains, but so far requires constant human supervision. Here, we present Frapid, an automated open source code implementation of FRAP that fully handles cell identification through fuzzy logic analysis, drug dispensing with a custom-built fluid handler, image acquisition & analysis, and reporting. We successfully tested Frapid on 3 bromodomains as well as on spindlin1 (SPIN1), a methyl lysine binder, for the first time. PMID:26977352

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

    PubMed

    Piccini, GiovanniMaria; Alessio, Maristella; Sauer, Joachim

    2016-04-18

    The ab initio prediction of reaction rate constants for systems with hundreds of atoms with an accuracy that is comparable to experiment is a challenge for computational quantum chemistry. We present a divide-and-conquer strategy that departs from the potential energy surfaces obtained by standard density functional theory with inclusion of dispersion. The energies of the reactant and transition structures are refined by wavefunction-type calculations for the reaction site. Thermal effects and entropies are calculated from vibrational partition functions, and the anharmonic frequencies are calculated separately for each vibrational mode. This method is applied to a key reaction of an industrially relevant catalytic process, the methylation of small alkenes over zeolites. The calculated reaction rate constants (free energies), pre-exponential factors (entropies), and enthalpy barriers show that our computational strategy yields results that agree with experiment within chemical accuracy limits (less than one order of magnitude). PMID:27008460

  18. Ab Initio Calculation of Rate Constants for Molecule–Surface Reactions with Chemical Accuracy

    PubMed Central

    Piccini, GiovanniMaria; Alessio, Maristella

    2016-01-01

    Abstract The ab initio prediction of reaction rate constants for systems with hundreds of atoms with an accuracy that is comparable to experiment is a challenge for computational quantum chemistry. We present a divide‐and‐conquer strategy that departs from the potential energy surfaces obtained by standard density functional theory with inclusion of dispersion. The energies of the reactant and transition structures are refined by wavefunction‐type calculations for the reaction site. Thermal effects and entropies are calculated from vibrational partition functions, and the anharmonic frequencies are calculated separately for each vibrational mode. This method is applied to a key reaction of an industrially relevant catalytic process, the methylation of small alkenes over zeolites. The calculated reaction rate constants (free energies), pre‐exponential factors (entropies), and enthalpy barriers show that our computational strategy yields results that agree with experiment within chemical accuracy limits (less than one order of magnitude). PMID:27008460

  19. Construction and accuracy of partial differential equation approximations to the chemical master equation.

    PubMed

    Grima, Ramon

    2011-11-01

    The mesoscopic description of chemical kinetics, the chemical master equation, can be exactly solved in only a few simple cases. The analytical intractability stems from the discrete character of the equation, and hence considerable effort has been invested in the development of Fokker-Planck equations, second-order partial differential equation approximations to the master equation. We here consider two different types of higher-order partial differential approximations, one derived from the system-size expansion and the other from the Kramers-Moyal expansion, and derive the accuracy of their predictions for chemical reactive networks composed of arbitrary numbers of unimolecular and bimolecular reactions. In particular, we show that the partial differential equation approximation of order Q from the Kramers-Moyal expansion leads to estimates of the mean number of molecules accurate to order Ω(-(2Q-3)/2), of the variance of the fluctuations in the number of molecules accurate to order Ω(-(2Q-5)/2), and of skewness accurate to order Ω(-(Q-2)). We also show that for large Q, the accuracy in the estimates can be matched only by a partial differential equation approximation from the system-size expansion of approximate order 2Q. Hence, we conclude that partial differential approximations based on the Kramers-Moyal expansion generally lead to considerably more accurate estimates in the mean, variance, and skewness than approximations of the same order derived from the system-size expansion. PMID:22181475

  20. Motivational Factors Contributing to Turkish High School Students' Achievement in Gases and Chemical Reactions

    ERIC Educational Resources Information Center

    Kadioglu, Cansel; Uzuntiryaki, Esen

    2008-01-01

    This study aimed to investigate the contribution of motivational factors to 10th grade students' achievement in gases and chemical reactions in chemistry. Three hundred fifty nine 10th grade students participated in the study. The Gases and Chemical Reactions Achievement Test and the Motivated Strategies for Learning Questionnaire were…

  1. Norm-conserving pseudopotentials with chemical accuracy compared to all-electron calculations

    NASA Astrophysics Data System (ADS)

    Willand, Alex; Kvashnin, Yaroslav O.; Genovese, Luigi; Vázquez-Mayagoitia, Álvaro; Deb, Arpan Krishna; Sadeghi, Ali; Deutsch, Thierry; Goedecker, Stefan

    2013-03-01

    By adding a nonlinear core correction to the well established dual space Gaussian type pseudopotentials for the chemical elements up to the third period, we construct improved pseudopotentials for the Perdew-Burke-Ernzerhof [J. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996), 10.1103/PhysRevLett.77.3865] functional and demonstrate that they exhibit excellent accuracy. Our benchmarks for the G2-1 test set show average atomization energy errors of only half a kcal/mol. The pseudopotentials also remain highly reliable for high pressure phases of crystalline solids. When supplemented by empirical dispersion corrections [S. Grimme, J. Comput. Chem. 27, 1787 (2006), 10.1002/jcc.20495; S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, J. Chem. Phys. 132, 154104 (2010), 10.1063/1.3382344] the average error in the interaction energy between molecules is also about half a kcal/mol. The accuracy that can be obtained by these pseudopotentials in combination with a systematic basis set is well superior to the accuracy that can be obtained by commonly used medium size Gaussian basis sets in all-electron calculations.

  2. Peaks, plateaus, numerical instabilities, and achievable accuracy in Galerkin and norm minimizing procedures for solving Ax=b

    SciTech Connect

    Cullum, J.

    1994-12-31

    Plots of the residual norms generated by Galerkin procedures for solving Ax = b often exhibit strings of irregular peaks. At seemingly erratic stages in the iterations, peaks appear in the residual norm plot, intervals of iterations over which the norms initially increase and then decrease. Plots of the residual norms generated by related norm minimizing procedures often exhibit long plateaus, sequences of iterations over which reductions in the size of the residual norm are unacceptably small. In an earlier paper the author discussed and derived relationships between such peaks and plateaus within corresponding Galerkin/Norm Minimizing pairs of such methods. In this paper, through a set of numerical experiments, the author examines connections between peaks, plateaus, numerical instabilities, and the achievable accuracy for such pairs of iterative methods. Three pairs of methods, GMRES/Arnoldi, QMR/BCG, and two bidiagonalization methods are studied.

  3. Cognitive Processing Profiles of School-Age Children Who Meet Low-Achievement, IQ-Discrepancy, or Dual Criteria for Underachievement in Oral Reading Accuracy

    ERIC Educational Resources Information Center

    Van Santen, Frank W.

    2012-01-01

    The purpose of this study was to compare the cognitive processing profiles of school-age children (ages 7 to 17) who met criteria for underachievement in oral reading accuracy based on three different methods: 1) use of a regression-based IQ-achievement discrepancy only (REGonly), 2) use of a low-achievement cutoff only (LAonly), and 3) use of a…

  4. Linear Discriminant Analysis Achieves High Classification Accuracy for the BOLD fMRI Response to Naturalistic Movie Stimuli.

    PubMed

    Mandelkow, Hendrik; de Zwart, Jacco A; Duyn, Jeff H

    2016-01-01

    Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI). However, conventional fMRI analysis based on statistical parametric mapping (SPM) and the general linear model (GLM) is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA), have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past, this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbor (NN), Gaussian Naïve Bayes (GNB), and (regularized) Linear Discriminant Analysis (LDA) in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie. Results show that LDA regularized by principal component analysis (PCA) achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2 s apart during a 300 s movie (chance level 0.7% = 2 s/300 s). The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

  5. Linear Discriminant Analysis Achieves High Classification Accuracy for the BOLD fMRI Response to Naturalistic Movie Stimuli

    PubMed Central

    Mandelkow, Hendrik; de Zwart, Jacco A.; Duyn, Jeff H.

    2016-01-01

    Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI). However, conventional fMRI analysis based on statistical parametric mapping (SPM) and the general linear model (GLM) is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA), have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past, this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbor (NN), Gaussian Naïve Bayes (GNB), and (regularized) Linear Discriminant Analysis (LDA) in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie. Results show that LDA regularized by principal component analysis (PCA) achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2 s apart during a 300 s movie (chance level 0.7% = 2 s/300 s). The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

  6. Accuracy, precision and economics: The cost of cutting-edge chemical analyses

    NASA Astrophysics Data System (ADS)

    Hamilton, B.; Hannigan, R.; Jones, C.; Chen, Z.

    2002-12-01

    Otolith (fish ear bone) chemistry has proven to be an exceptional tool for the identification of essential fish habitats in marine and freshwater environments. These measurements, which explore the variations in trace element content of otoliths relative to Calcium (eg., Ba/Ca, Mg/Ca etc.), provide data to resolve the differences in habitat water chemistry on the watershed to catchment scale. The vast majority of these analyses are performed by laser ablation ICP-MS using a high-resolution instrument. However, few laboratories are equipped with this configuration and many researchers measure the trace element chemistry of otoliths by whole digestion ICP-MS using lower resolution quadrupole instruments. This study examines the differences in accuracy and precision between three elemental analysis methods using whole otolith digestion on a low resolution ICP-MS (ELAN 9000). The first, and most commonly used, technique is external calibration with internal standardization. This technique is the most cost-effective but also is one with limitations in terms of method detection. The second, standard addition is more costly in terms of time and use of standard materials but offers gains in precision and accuracy. The third, isotope dilution, is the least cost effective but the most accurate of elemental analysis techniques. Based on the results of this study, which seeks to identify the technique which is the easiest to implement yet has the precision and accuracy necessary to resolve spatial variations in habitats, we conclude that external calibration with internal standardization can be sufficient to revolve spatial and temporal variations in marine and estuarine environments (+/- 6-8% accuracy). Standard addition increases the accuracy of measurements to 2-5% and is ideal for freshwater studies. While there is a gain in accuracy and precision with isotope dilution, the spatial and temporal resolution is no greater with this technique than the other.

  7. Strategies for Achieving High Sequencing Accuracy for Low Diversity Samples and Avoiding Sample Bleeding Using Illumina Platform

    PubMed Central

    Mitra, Abhishek; Skrzypczak, Magdalena; Ginalski, Krzysztof; Rowicka, Maga

    2015-01-01

    analysis can be repeated from saved sequencing images using the Long Template Protocol to increase accuracy. PMID:25860802

  8. ACCURACY OF PESTICIDE REFERENCE STANDARD SOLUTIONS. PART II. CHEMICAL STABILITY UNDER FOUR STORAGE CONDITIONS

    EPA Science Inventory

    A study was undertaken to assess the long-term chemical stability of dilute standard pesticide solutions of 4 compound classes. The solutions were studied under 4 storage conditions: freezer at -15C; refrigerator at 3C; ambient temperature in the dark; and ambient temperature on ...

  9. Achieving Accuracy Requirements for Forest Biomass Mapping: A Data Fusion Method for Estimating Forest Biomass and LiDAR Sampling Error with Spaceborne Data

    NASA Technical Reports Server (NTRS)

    Montesano, P. M.; Cook, B. D.; Sun, G.; Simard, M.; Zhang, Z.; Nelson, R. F.; Ranson, K. J.; Lutchke, S.; Blair, J. B.

    2012-01-01

    The synergistic use of active and passive remote sensing (i.e., data fusion) demonstrates the ability of spaceborne light detection and ranging (LiDAR), synthetic aperture radar (SAR) and multispectral imagery for achieving the accuracy requirements of a global forest biomass mapping mission. This data fusion approach also provides a means to extend 3D information from discrete spaceborne LiDAR measurements of forest structure across scales much larger than that of the LiDAR footprint. For estimating biomass, these measurements mix a number of errors including those associated with LiDAR footprint sampling over regional - global extents. A general framework for mapping above ground live forest biomass (AGB) with a data fusion approach is presented and verified using data from NASA field campaigns near Howland, ME, USA, to assess AGB and LiDAR sampling errors across a regionally representative landscape. We combined SAR and Landsat-derived optical (passive optical) image data to identify forest patches, and used image and simulated spaceborne LiDAR data to compute AGB and estimate LiDAR sampling error for forest patches and 100m, 250m, 500m, and 1km grid cells. Forest patches were delineated with Landsat-derived data and airborne SAR imagery, and simulated spaceborne LiDAR (SSL) data were derived from orbit and cloud cover simulations and airborne data from NASA's Laser Vegetation Imaging Sensor (L VIS). At both the patch and grid scales, we evaluated differences in AGB estimation and sampling error from the combined use of LiDAR with both SAR and passive optical and with either SAR or passive optical alone. This data fusion approach demonstrates that incorporating forest patches into the AGB mapping framework can provide sub-grid forest information for coarser grid-level AGB reporting, and that combining simulated spaceborne LiDAR with SAR and passive optical data are most useful for estimating AGB when measurements from LiDAR are limited because they minimized

  10. Approaches for achieving long-term accuracy and precision of δ18O and δ2H for waters analyzed using laser absorption spectrometers.

    PubMed

    Wassenaar, Leonard I; Coplen, Tyler B; Aggarwal, Pradeep K

    2014-01-21

    The measurement of δ(2)H and δ(18)O in water samples by laser absorption spectroscopy (LAS) are adopted increasingly in hydrologic and environmental studies. Although LAS instrumentation is easy to use, its incorporation into laboratory operations is not as easy, owing to extensive offline data manipulation required for outlier detection, derivation and application of algorithms to correct for between-sample memory, correcting for linear and nonlinear instrumental drift, VSMOW-SLAP scale normalization, and in maintaining long-term QA/QC audits. Here we propose a series of standardized water-isotope LAS performance tests and routine sample analysis templates, recommended procedural guidelines, and new data processing software (LIMS for Lasers) that altogether enables new and current LAS users to achieve and sustain long-term δ(2)H and δ(18)O accuracy and precision for these important isotopic assays. PMID:24328223

  11. Visions, Achievements, and Challenges of the Division of Chemical Education during the Early Years

    NASA Astrophysics Data System (ADS)

    Benfey, Theodor

    2003-06-01

    The first decade of the American Chemical Society Division of Chemical Education (DIVCHED) was most extraordinary. It began in 1924 with grand visions, plans, and accomplishments, and ended in the Depression. The period was dominated by two figures, Neil Gordon, founding editor of the Journal of Chemical Education, and Francis Garvan, the United States Alien Property Custodian who, through the Chemical Foundation, poured money into chemical education for his own purposes. At Garvan's urging, DIVCHED also published a journal for high school teachers, The Chemistry Leaflet, edited by Pauline Beery Mack, later famous for advising NASA on bone density loss in space travel. The Chemistry Leaflet later appeared as the ACS educational magazine, Chemistry. Woven into the paper are three continuing concerns of the DIVCHED: sustained service to the high school teacher, participation of university and industrial leaders in DIVCHED, and women in chemical education.

  12. Achieving Chemical Equilibrium: The Role of Imposed Conditions in the Ammonia Formation Reaction

    ERIC Educational Resources Information Center

    Tellinghuisen, Joel

    2006-01-01

    Under conditions of constant temperature T and pressure P, chemical equilibrium occurs in a closed system (fixed mass) when the Gibbs free energy G of the reaction mixture is minimized. However, when chemical reactions occur under other conditions, other thermodynamic functions are minimized or maximized. For processes at constant T and volume V,…

  13. [Hygienic aspects of the industrialization and intensification of chemical seed protection. Achievements and problems].

    PubMed

    Borisenko, N F; Petrichenko, L N

    1989-01-01

    Design improvement of machines and devices for seed decontamination with account of the proposed hygienic recommendations promoted sanitation of operators' working conditions. Introduction of progressive technology (damping, inlaid work) enables one to reduce pesticide application and to decrease ecologic hazard of seed chemical protection. PMID:2591811

  14. Ambient Concentrations of Metabolic Disrupting Chemicals and Children's Academic Achievement in El Paso, Texas.

    PubMed

    Clark-Reyna, Stephanie E; Grineski, Sara E; Collins, Timothy W

    2016-01-01

    Concerns about children's weight have steadily risen alongside the manufacture and use of myriad chemicals in the US. One class of chemicals, known as metabolic disruptors, interfere with human endocrine and metabolic functioning and are of specific concern to children's health and development. This article examines the effect of residential concentrations of metabolic disrupting chemicals on children's school performance for the first time. Census tract-level ambient concentrations for known metabolic disruptors come from the US Environmental Protection Agency's National Air Toxics Assessment. Other measures were drawn from a survey of primary caretakers of 4th and 5th grade children in El Paso Independent School District (El Paso, TX, USA). A mediation model is employed to examine two hypothetical pathways through which the ambient level of metabolic disruptors at a child's home might affect grade point average. Results indicate that concentrations of metabolic disruptors are statistically significantly associated with lower grade point averages directly and indirectly through body mass index. Findings from this study have practical implications for environmental justice research and chemical policy reform in the US. PMID:27598179

  15. Understanding Possibilities and Limitations of Abstract Chemical Representations for Achieving Conceptual Understanding

    ERIC Educational Resources Information Center

    Corradi, David M. J.; Elen, Jan; Schraepen, Beno; Clarebout, Geraldine

    2014-01-01

    When learning with abstract and scientific multiple external representations (MERs), low prior knowledge learners are said to have difficulties in using these MERs to achieve conceptual understanding. Yet little is known about what these limitations precisely entail. In order to understand this, we presented 101 learners with low prior knowledge…

  16. Chemically Controlling Black Phosphorus Exfoliation to Achieve Variable-Sized Phosphorene

    NASA Astrophysics Data System (ADS)

    Ng, Amy; Sutto, Thomas; Deng, Yexin; Stroud, Rhonda; Brintlinger, Todd; Ye, Peide; Bassim, Nabil

    Phosphorene is the 2-dimensional form of phosphorus and a close relative of graphene. It has a nonzero fundamental band gap that gives rise to semiconductor properties, which makes it highly desirable for numerous applications in optoelectronics and as a replacement channel for conventional semiconductor devices. However, difficulties in isolating large area single-, few-, or multi-layer sheets are an impediment to realizing the aforementioned applications. We are investigating multiple chemical routes for optimal production of phosphorene sheets. Utilizing various solvent systems, ranging from a simple ethanol to dimethylformamide to more viscous ionic liquids, we have obtained flakes of differing thicknesses and sizes. We characterized the structure and composition of the resulting phosphorene sheets with aberration-corrected scanning transmission electron microscopy in addition to optical/macroscopic studies. Flake size, quality, and quantity obtained as a function of the solvent system, where factors such as viscosity, surface tension, chemical behavior, and degree of agitation, will be presented. This work was supported by the Office of Naval Research.

  17. Achieving successful delivery of oligonucleotides--From physico-chemical characterization to in vivo evaluation.

    PubMed

    Scomparin, Anna; Polyak, Dina; Krivitsky, Adva; Satchi-Fainaro, Ronit

    2015-11-01

    RNA interference is one of the most promising fields in modern medicine to treat several diseases, ranging from cancer to cardiac diseases, passing through viral infections and metabolic pathologies. Since the discovery of the potential therapeutic properties of non-self oligonucleotides, it was clear that it is important to develop delivery systems that are able to increase plasma stability and bestow membrane-crossing abilities to the oligonucleotides in order to reach their cytoplasmic targets. Polymer therapeutics, among other systems, are widely investigated as delivery systems for therapeutic agents, such as oligonucleotides. Physico-chemical characterization of the supramolecular polyplexes obtained upon charge interaction or covalent conjugation between the polymeric carrier and the oligonucleotides is critical. Appropriate characterization is fundamental in order to predict and understand the in vivo silencing efficacy and to avoid undesired side effects and toxicity profile. Shedding light on the physico-chemical and in vitro requirements of a polyplex leads to an efficient in vivo delivery system for RNAi therapeutics. In this review, we will present the most common techniques for characterization of obtained polymer/oligonucleotide polyplexes and an up-to-date state of the art in vivo preclinical and clinical studies. This is the first review to deal with the difficulties in appropriate characterization of small interfering RNA (siRNA) or microRNA (miRNA) polyplexes and conjugates which limit the clinical translation of this promising technology. PMID:25916823

  18. Factors influencing achievement of chemical order in tetragonal FeNi

    NASA Astrophysics Data System (ADS)

    Bordeaux, Nina; Montes-Arango, Ana Maria; Liu, Jiaxing; Barmak, Katayun; Lewis, Laura Henderson

    2015-03-01

    Chemically ordered ferromagnetic compounds with the L10 structure have attracted wide interest for rare-earth-free permanent magnet applications. In particular, L10-structured FeNi is a promising candidate due to the abundance and low cost of the constituent elements and high theoretical maximum energy product (BH)max = 42 MGOe. Synthesis of L10 FeNi has been hindered by extremely sluggish kinetics below the equilibrium order-disorder temperature TO/D = 320 ° and the phase is known to form in meteorites over millions of years. In this work, the thermodynamic stability of the L10 phase and kinetics of the L10 --> fcc magnetostructural phase transformation are quantitatively determined via magnetic and thermal measurements of bulk L10 FeNi extracted from meteorites. Influences on phase transformation kinetics, including effects of magnetism, will be discussed.

  19. Versatile p-Type Chemical Doping to Achieve Ideal Flexible Graphene Electrodes.

    PubMed

    Han, Tae-Hee; Kwon, Sung-Joo; Li, Nannan; Seo, Hong-Kyu; Xu, Wentao; Kim, Kwang S; Lee, Tae-Woo

    2016-05-17

    We report effective solution-processed chemical p-type doping of graphene using trifluoromethanesulfonic acid (CF3 SO3 H, TFMS), that can provide essential requirements to approach an ideal flexible graphene anode for practical applications: i) high optical transmittance, ii) low sheet resistance (70 % decrease), iii) high work function (0.83 eV increase), iv) smooth surface, and iv) air-stability at the same time. The TFMS-doped graphene formed nearly ohmic contact with a conventional organic hole transporting layer, and a green phosphorescent organic light-emitting diode with the TFMS-doped graphene anode showed lower operating voltage, and higher device efficiencies (104.1 cd A(-1) , 80.7 lm W(-1) ) than those with conventional ITO (84.8 cd A(-1) , 73.8 lm W(-1) ). PMID:27072071

  20. Chemical Manufacturing and Refining Industry Legitimacy: Reflective Management, Trust, Precrisis Communication to Achieve Community Efficacy.

    PubMed

    Heath, Robert L; Lee, Jaesub

    2016-06-01

    Calls for emergency right-to-know in the 1980s, and, in the 1990s, risk management planning, motivated U.S. chemical manufacturing and refining industries to operationalize a three-pronged approach to risk minimization and communication: reflective management to increase legitimacy, operational safety programs to raise trust, and community engagement designed to facilitate citizens' emergency response efficacy. To assess these management, operational, and communication initiatives, communities (often through Local Emergency Planning Committees) monitored the impact of such programs. In 2012, the fourth phase of a quasi-longitudinal study was conducted to assess the effectiveness of operational change and community outreach in one bellwether community. This study focuses on legitimacy, trust, and response efficacy to suggest that an industry can earn legitimacy credits by raising its safety and environmental impact standards, by building trust via that change, and by communicating emergency response messages to near residents to raise their response efficacy. As part of its campaign to demonstrate its concern for community safety through research, planning, and implementation of safe operations and viable emergency response systems, this industry uses a simple narrative of risk/emergency response-shelter-in-place-communicated by a spokes-character: Wally Wise Guy. PMID:26503696

  1. The Effects of Contingent Praise Upon the Achievement of a Deficit Junior High School Student in Oral Reading Accuracy in Probes Above Her Functional Grade Level.

    ERIC Educational Resources Information Center

    Proe, Susan; Wade, David

    Evaluated was the effectiveness of three training procedures (imitation training, imitation training with praise, and imitation training with points for an art supply contingency) in improving the oral reading accuracy and reading comprehension of a 13-year-old girl whose functional reading was at the second grade level. The procedures were…

  2. Achieving synergy between chemical oxidation and stabilization in a contaminated soil.

    PubMed

    Srivastava, Vipul J; Hudson, Jeffrey Michael; Cassidy, Daniel P

    2016-07-01

    Eight in situ solidification/stabilization (ISS) amendments were tested to promote in situ chemical oxidation (ISCO) with activated persulfate (PS) in a contaminated soil. A 3% (by weight) dose of all ISS amendments selected for this study completely activated a 1.5% dose of PS within 3 h by raising temperatures above 30 °C (heat activation) and/or increasing pH above 10.5 (alkaline activation). Heat is released by the reaction of CaO with water, and pH increases because this reaction produces Ca(OH)2. Heat activation is preferred because it generates 2 mol of oxidizing radicals per mole of PS, whereas alkaline activation releases only 1. The relative contribution of heat vs. alkaline activation increased with CaO content of the ISS amendment, which was reflected by enhanced contaminant oxidation with increasing CaO content, and was confirmed by comparing to controls promoting purely heat or alkaline (NaOH) activation. The test soil was contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAH), particularly naphthalene (NAP). ISS-activated PS oxidized between 47% and 84% of the BTEX & NAP, and between 13% and 33% of the higher molecular weight PAH. ISS-activated PS reduced the leachability of BTEX & NAP by 76%-91% and of the 17 PAH by 83%-96%. Combined ISCO/ISS reduced contaminant leachability far than ISCO or ISS treatments alone, demonstrating the synergy that is possible with combined remedies. PMID:27088536

  3. High accuracy NMR chemical shift corrected for bulk magnetization as a tool for structural elucidation of dilutable microemulsions. Part 1 - Proof of concept.

    PubMed

    Hoffman, Roy E; Darmon, Eliezer; Aserin, Abraham; Garti, Nissim

    2016-02-01

    In microemulsions, changes in droplet size and shape and possible transformations occur under various conditions. They are difficult to characterize by most analytical tools because of their nano-sized structure and dynamic nature. Several methods are usually combined to obtain reliable information, guiding the scientist in understanding their physical behavior. We felt that there is a need for a technique that complements those in use today in order to provide more information on the microemulsion behavior, mainly as a function of dilution with water. The improvement of NMR chemical shift measurements independent of bulk magnetization effects makes it possible to study the very weak intermolecular chemical shift effects. In the present study, we used NMR high resolution magic angle spinning to measure the chemical shift very accurately, free of bulk magnetization effects. The chemical shift of microemulsion components is measured as a function of the water content in order to validate the method in an interesting and promising, U-type dilutable microemulsion, which had been previously studied by a variety of techniques. Phase transition points of the microemulsion (O/W, bicontinuous, W/O) and changes in droplet shape were successfully detected using high-accuracy chemical shift measurements. We analyzed the results and found them to be compatible with the previous studies, paving the way for high-accuracy chemical shifts to be used for the study of other microemulsion systems. We detected two transition points along the water dilution line of the concentrate (reverse micelles) corresponding to the transition from swollen W/O nano-droplets to bicontinuous to the O/W droplets along with the changes in the droplets' sizes and shapes. The method seems to be in excellent agreement with other previously studied techniques and shows the advantage of this easy and valid technique. PMID:25113928

  4. The Effect of Molecular Conformation on the Accuracy of Theoretical (1)H and (13)C Chemical Shifts Calculated by Ab Initio Methods for Metabolic Mixture Analysis.

    PubMed

    Chikayama, Eisuke; Shimbo, Yudai; Komatsu, Keiko; Kikuchi, Jun

    2016-04-14

    NMR spectroscopy is a powerful method for analyzing metabolic mixtures. The information obtained from an NMR spectrum is in the form of physical parameters, such as chemical shifts, and construction of databases for many metabolites will be useful for data interpretation. To increase the accuracy of theoretical chemical shifts for development of a database for a variety of metabolites, the effects of sets of conformations (structural ensembles) and the levels of theory on computations of theoretical chemical shifts were systematically investigated for a set of 29 small molecules in the present study. For each of the 29 compounds, 101 structures were generated by classical molecular dynamics at 298.15 K, and then theoretical chemical shifts for 164 (1)H and 123 (13)C atoms were calculated by ab initio quantum chemical methods. Six levels of theory were used by pairing Hartree-Fock, B3LYP (density functional theory), or second order Møller-Plesset perturbation with 6-31G or aug-cc-pVDZ basis set. The six average fluctuations in the (1)H chemical shift were ±0.63, ± 0.59, ± 0.70, ± 0.62, ± 0.75, and ±0.66 ppm for the structural ensembles, and the six average errors were ±0.34, ± 0.27, ± 0.32, ± 0.25, ± 0.32, and ±0.25 ppm. The results showed that chemical shift fluctuations with changes in the conformation because of molecular motion were larger than the differences between computed and experimental chemical shifts for all six levels of theory. In conclusion, selection of an appropriate structural ensemble should be performed before theoretical chemical shift calculations for development of an accurate database for a variety of metabolites. PMID:26963288

  5. Growth of large size diamond single crystals by plasma assisted chemical vapour deposition: Recent achievements and remaining challenges

    NASA Astrophysics Data System (ADS)

    Tallaire, Alexandre; Achard, Jocelyn; Silva, François; Brinza, Ovidiu; Gicquel, Alix

    2013-02-01

    Diamond is a material with outstanding properties making it particularly suited for high added-value applications such as optical windows, power electronics, radiation detection, quantum information, bio-sensing and many others. Tremendous progresses in its synthesis by microwave plasma assisted chemical vapour deposition have allowed obtaining single crystal optical-grade material with thicknesses of up to a few millimetres. However the requirements in terms of size, purity and crystalline quality are getting more and more difficult to achieve with respect to the forecasted applications, thus pushing the synthesis method to its scientific and technological limits. In this paper, after a short description of the operating principles of the growth technique, the challenges of increasing crystal dimensions both laterally and vertically, decreasing and controlling point and extended defects as well as modulating crystal conductivity by an efficient doping will be detailed before offering some insights into ways to overcome them.

  6. Accuracy of Calculated Chemical Shifts in Carbon 1s Ionization Energies from Single-Reference ab Initio Methods and Density Functional Theory.

    PubMed

    Holme, Alf; Børve, Knut J; Sæthre, Leif J; Thomas, T Darrah

    2011-12-13

    A database of 77 adiabatic carbon 1s ionization energies has been prepared, covering linear and cyclic alkanes and alkenes, linear alkynes, and methyl- or fluoro-substituted benzenes. Individual entries are believed to carry uncertainties of less than 30 meV in ionization energies and less than 20 meV for shifts in ionization energies. The database provides an unprecedented opportunity for assessing the accuracy of theoretical schemes for computing inner-shell ionization energies and their corresponding chemical shifts. Chemical shifts in carbon 1s ionization energies have been computed for all molecules in the database using Hartree-Fock, Møller-Plesset (MP) many-body perturbation theory of order 2 and 3 as well as various approximations to full MP4, and the coupled-cluster approximation with single- and double-excitation operators (CCSD) and also including a perturbational estimate of the energy effect of triple-excitation operators (CCSD(T)). Moreover, a wide range of contemporary density functional theory (DFT) methods are also evaluated with respect to computing experimental shifts in C1s ionization energies. Whereas the top ab initio methods reproduce the observed shifts almost to within the experimental uncertainty, even the best-performing DFT approaches meet with twice the root-mean-squared error and thrice the maximum error compared to CCSD(T). However, a number of different density energy functionals still afford sufficient accuracy to become tools in the analysis of complex C1s photoelectron spectra. PMID:26598356

  7. The coarse pointing assembly for SILEX program or how to achieve outstanding pointing accuracy with simple hardware associated with consistent control laws

    NASA Astrophysics Data System (ADS)

    Buvat, Daniel; Muller, Gerard; Peyrot, Patrick

    1991-06-01

    Attention is given to the coarse pointing assembly (CPA) for the SILEX program, designed on the basis of 10 years of MATRA experience in very accurate drive mechanisms successfully conducted by the SPOT 1 and 2 flights as well as EURECA IOC. The basic key design feature of the mechanism is a 1200-step stepper motor driven in microstepping with harmonic defects compensation. This allows very low torque noise associated with a high accuracy (0.01 deg). The direct drive principle avoids backlash and permits a linear control of the output shaft of each drive. The only parts susceptible to possible wear are the ball bearings, which have a design margin of greater than 1000 for 10 yr of service life. In order to meet the dynamic performances required by SILEX, a closed loop active damping system is added to each drive unit. Two accelerometers used in a differential way sense the hinge microvibrations and an active damping loop reduces their Q factor down to a few dB. All CPA electrical parts (including motor, optical encoder, and accelerometer) are redundant to avoid single point of failure.

  8. The influence of multivariate analysis methods and target grain size on the accuracy of remote quantitative chemical analysis of rocks using laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Anderson, Ryan B.; Morris, Richard V.; Clegg, Samuel M.; Bell, James F.; Wiens, Roger C.; Humphries, Seth D.; Mertzman, Stanley A.; Graff, Trevor G.; McInroy, Rhonda

    2011-10-01

    Laser-induced breakdown spectroscopy (LIBS) was used to quantitatively analyze 195 rock slab samples with known bulk chemical compositions, 90 pressed-powder samples derived from a subset of those rocks, and 31 pressed-powder geostandards under conditions that simulate the ChemCam instrument on the Mars Science Laboratory Rover (MSL), Curiosity. The low-volatile (<2 wt.%) silicate samples (90 rock slabs, corresponding powders, and 22 geostandards) were split into training, validation, and test sets. The LIBS spectra and chemical compositions of the training set were used with three multivariate methods to predict the chemical compositions of the test set. The methods were partial least squares (PLS), multilayer perceptron artificial neural networks (MLP ANNs) and cascade correlation (CC) ANNs. Both the full LIBS spectrum and the intensity at five pre-selected spectral channels per major element (feature selection) were used as input data for the multivariate calculations. The training spectra were supplied to the algorithms without averaging ( i.e. five spectra per target) and with averaging ( i.e. all spectra from the same target averaged and treated as one spectrum). In most cases neural networks did not perform better than PLS for our samples. PLS2 without spectral averaging outperformed all other procedures on the basis of lowest quadrature root mean squared error (RMSE) for both the full test set and the igneous rocks test set. The RMSE for PLS2 using the igneous rock slab test set is: 3.07 wt.% SiO 2, 0.87 wt.% TiO 2, 2.36 wt.% Al 2O 3, 2.20 wt.% Fe 2O 3, 0.08 wt.% MnO, 1.74 wt.% MgO, 1.14 wt.% CaO, 0.85 wt.% Na 2O, 0.81 wt.% K 2O. PLS1 with feature selection and averaging had a higher quadrature RMSE than PLS2, but merits further investigation as a method of reducing data volume and computation time and potentially improving prediction accuracy, particularly for samples that differ significantly from the training set. Precision and accuracy were influenced

  9. Chemical exchange saturation transfer MR imaging of articular cartilage glycosaminoglycans at 3 T: Accuracy of B0 Field Inhomogeneity corrections with gradient echo method.

    PubMed

    Wei, Wenbo; Jia, Guang; Flanigan, David; Zhou, Jinyuan; Knopp, Michael V

    2014-01-01

    Glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) is an important molecular MRI methodology developed to assess changes in cartilage GAG concentrations. The correction for B0 field inhomogeneity is technically crucial in gagCEST imaging. This study evaluates the accuracy of the B0 estimation determined by the dual gradient echo method and the effect on gagCEST measurements. The results were compared with those from the commonly used z-spectrum method. Eleven knee patients and three healthy volunteers were scanned. Dual gradient echo B0 maps with different ∆TE values (1, 2, 4, 8, and 10 ms) were acquired. The asymmetry of the magnetization transfer ratio at 1 ppm offset referred to the bulk water frequency, MTRasym(1 ppm), was used to quantify cartilage GAG levels. The B0 shifts for all knee patients using the z-spectrum and dual gradient echo methods are strongly correlated for all ∆TE values used (r = 0.997 to 0.786, corresponding to ∆TE = 10 to 1 ms). The corrected MTRasym(1 ppm) values using the z-spectrum method (1.34% ± 0.74%) highly agree only with those using the dual gradient echo methods with ∆TE = 10 ms (1.72% ± 0.80%; r = 0.924) and 8 ms (1.50% ± 0.82%; r = 0.712). The dual gradient echo method with longer ∆TE values (more than 8 ms) has an excellent correlation with the z-spectrum method for gagCEST imaging at 3T. PMID:24119460

  10. Gender Differences in Achievement in Calculating Reacting Masses from Chemical Equations among Secondary School Students in Makurdi Metropols

    ERIC Educational Resources Information Center

    Eriba, Joel O.; Ande, Sesugh

    2006-01-01

    Over the years there exists gender inequality in science achievement among senior secondary school students the world over. It is observed that the males score higher than the females in science and science- related examinations. This has created a big psychological alienation or depression in the minds of female students towards science and…

  11. Quantum Chemical Calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W.; Arnold, James O. (Technical Monitor)

    1997-01-01

    The current methods of quantum chemical calculations will be reviewed. The accent will be on the accuracy that can be achieved with these methods. The basis set requirements and computer resources for the various methods will be discussed. The utility of the methods will be illustrated with some examples, which include the calculation of accurate bond energies for SiF$_n$ and SiF$_n^+$ and the modeling of chemical data storage.

  12. Accuracy of deception judgments.

    PubMed

    Bond, Charles F; DePaulo, Bella M

    2006-01-01

    We analyze the accuracy of deception judgments, synthesizing research results from 206 documents and 24,483 judges. In relevant studies, people attempt to discriminate lies from truths in real time with no special aids or training. In these circumstances, people achieve an average of 54% correct lie-truth judgments, correctly classifying 47% of lies as deceptive and 61% of truths as nondeceptive. Relative to cross-judge differences in accuracy, mean lie-truth discrimination abilities are nontrivial, with a mean accuracy d of roughly .40. This produces an effect that is at roughly the 60th percentile in size, relative to others that have been meta-analyzed by social psychologists. Alternative indexes of lie-truth discrimination accuracy correlate highly with percentage correct, and rates of lie detection vary little from study to study. Our meta-analyses reveal that people are more accurate in judging audible than visible lies, that people appear deceptive when motivated to be believed, and that individuals regard their interaction partners as honest. We propose that people judge others' deceptions more harshly than their own and that this double standard in evaluating deceit can explain much of the accumulated literature. PMID:16859438

  13. The effects of reasoning, use of models, sex type, and their interactions on posttest achievement in chemical bonding after constant instruction

    NASA Astrophysics Data System (ADS)

    Staver, John R.; Halsted, Douglas A.

    The purpose of the authors in this study was to determine the effects of reasoning, use of models during testing, and sex type on posttest achievement in chemical bonding under controlled instruction. Eighty-four high school students taking chemistry were randomly assigned within their classes to models and no models groups for the posttest. Reasoning capabilities were assessed by the Piagetian Logical Operations Test (PLOT) (Staver & Gabel, JRST, Vol. 16, No. 6, 1979), prior to instruction. All students then received the same instruction on chemical bonding which included teacher demonstrations of concepts with three-dimensional molecular models, interspersed teacher questions during the introduction and development of concepts, student manipulation of three-dimensional molecular models during laboratory experiments, and text reading assignments on concepts prior to their instruction in class. The posttest on molecular geometry and shape contained three sections requiring memory and application (Bloom, Taxonomy of educational objective, handbook I: Cognitive domain. New York: David McKay, 1956). Data were analyzed by regression (Nie et al., Statistical package for the social sciences, 2nd ed. New York: McGraw-Hill, 1975). Results indicate that reasoning accounted for a significant portion (p < 0.05) of the variance in the total score, memory score, and application score, but not on the synthesis score of the posttest. Use of models and sex type did not account for a significant (p > 0.05) portion of the variance on total scores or any section of posttest. The three-way interaction of reasoning, model usage, and sex type accounted for a significant portion (p < 0.05) of the variance in total scores, and in the memory and application sections of the posttest. Discussion focused on the results, conclusions, and implications for science teaching.

  14. Toward Chemical Accuracy in the Description of Ion-Water Interactions through Many-Body Representations. I. Halide-Water Dimer Potential Energy Surfaces.

    PubMed

    Bajaj, Pushp; Götz, Andreas W; Paesani, Francesco

    2016-06-14

    Despite recent progress, a unified understanding of how ions affect the structure and dynamics of water across different phases remains elusive. Here, we report the development of full-dimensional many-body potential energy functions, called MB-nrg (Many-Body-energy), for molecular simulations of halide ion-water systems from the gas phase to the condensed phase. The MB-nrg potentials are derived entirely from "first-principles" calculations carried out at the F12 explicitly correlated coupled-cluster level including single, double, and perturbative triple excitations, CCSD(T)-F12, in the complete basis set limit. Building upon the functional form of the MB-pol water potential, the MB-nrg potentials are expressed through the many-body expansion of the total energy in terms of explicit contributions representing one-body, two-body, and three-body interactions, with all higher-order contributions being described by classical induction. The specific focus of this study is on the MB-nrg two-body terms representing the full-dimensional potential energy surfaces (PESs) of the corresponding H2O-X(-) dimers, with X(-)= F(-), Cl(-), Br(-), and I(-). The accuracy of the MB-nrg PESs is systematically assessed through extensive comparisons with results obtained using both ab initio models and polarizable force fields for energies, structures, and harmonic frequencies of the H2O-X(-) dimers. PMID:27145081

  15. Achieving low effluent NO3-N and TN concentrations in low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio without using external carbon source

    NASA Astrophysics Data System (ADS)

    Cao, Jiashun; Oleyiblo, Oloche James; Xue, Zhaoxia; Otache, Y. Martins; Feng, Qian

    2015-07-01

    Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal (BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic (A2/O). The ASM2d implemented on the platform of WEST2011 software and the BioWin activated sludge/anaerobic digestion (AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2d parameters (the reduction factor for denitrification , the maximum growth rate of heterotrophs (µH), the rate constant for stored polyphosphates in PAOs ( q pp), and the hydrolysis rate constant ( k h)) were adjusted. Whereas three BioWin parameters (aerobic decay rate ( b H), heterotrophic dissolved oxygen (DO) half saturation ( K OA), and Y P/acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations (ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen (N-NO3), total nitrogen (TN), and total phosphorus (TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio (COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.

  16. Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

    PubMed

    Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

    2013-01-01

    Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants. PMID:23863442

  17. VITAL NMR: Using Chemical Shift Derived Secondary Structure Information for a Limited Set of Amino Acids to Assess Homology Model Accuracy

    SciTech Connect

    Brothers, Michael C; Nesbitt, Anna E; Hallock, Michael J; Rupasinghe, Sanjeewa; Tang, Ming; Harris, Jason B; Baudry, Jerome Y; Schuler, Mary A; Rienstra, Chad M

    2011-01-01

    Homology modeling is a powerful tool for predicting protein structures, whose success depends on obtaining a reasonable alignment between a given structural template and the protein sequence being analyzed. In order to leverage greater predictive power for proteins with few structural templates, we have developed a method to rank homology models based upon their compliance to secondary structure derived from experimental solid-state NMR (SSNMR) data. Such data is obtainable in a rapid manner by simple SSNMR experiments (e.g., (13)C-(13)C 2D correlation spectra). To test our homology model scoring procedure for various amino acid labeling schemes, we generated a library of 7,474 homology models for 22 protein targets culled from the TALOS+/SPARTA+ training set of protein structures. Using subsets of amino acids that are plausibly assigned by SSNMR, we discovered that pairs of the residues Val, Ile, Thr, Ala and Leu (VITAL) emulate an ideal dataset where all residues are site specifically assigned. Scoring the models with a predicted VITAL site-specific dataset and calculating secondary structure with the Chemical Shift Index resulted in a Pearson correlation coefficient (-0.75) commensurate to the control (-0.77), where secondary structure was scored site specifically for all amino acids (ALL 20) using STRIDE. This method promises to accelerate structure procurement by SSNMR for proteins with unknown folds through guiding the selection of remotely homologous protein templates and assessing model quality.

  18. Improving Speaking Accuracy through Awareness

    ERIC Educational Resources Information Center

    Dormer, Jan Edwards

    2013-01-01

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

  19. Relative accuracy evaluation.

    PubMed

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

    2014-01-01

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

  20. Relative Accuracy Evaluation

    PubMed Central

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

    2014-01-01

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

  1. Towards Arbitrary Accuracy Inviscid Surface Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Hixon, Ray

    2002-01-01

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

  2. A new adaptive GMRES algorithm for achieving high accuracy

    SciTech Connect

    Sosonkina, M.; Watson, L.T.; Kapania, R.K.; Walker, H.F.

    1996-12-31

    GMRES(k) is widely used for solving nonsymmetric linear systems. However, it is inadequate either when it converges only for k close to the problem size or when numerical error in the modified Gram-Schmidt process used in the GMRES orthogonalization phase dramatically affects the algorithm performance. An adaptive version of GMRES (k) which tunes the restart value k based on criteria estimating the GMRES convergence rate for the given problem is proposed here. The essence of the adaptive GMRES strategy is to adapt the parameter k to the problem, similar in spirit to how a variable order ODE algorithm tunes the order k. With FORTRAN 90, which provides pointers and dynamic memory management, dealing with the variable storage requirements implied by varying k is not too difficult. The parameter k can be both increased and decreased-an increase-only strategy is described next followed by pseudocode.

  3. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, D.; Hashmall, J.

    1994-01-01

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

  4. Improved electrochemical stability at the surface of La(0.8)Sr(0.2)CoO3 achieved by surface chemical modification.

    PubMed

    Tsvetkov, Nikolai; Lu, Qiyang; Yildiz, Bilge

    2015-01-01

    The degradation of the surface chemistry on perovskite (ABO3) oxides is a critical issue for their performance in energy conversion systems such as solid oxide fuel/electrolysis cells and in splitting of H2O and CO2 to produce fuels. This degradation is typically in the form of segregation and phase separation of dopant cations from the A-site, driven by elastic and electrostatic energy minimization and kinetic demixing. In this study, deposition of Ti at the surface was found to hinder the dopant segregation and the corresponding electrochemical degradation on a promising SOFC cathode material, La(0.8)Sr(0.2)CoO3 (LSC). The surface of the LSC films was modified by Ti (denoted as LSC-T) deposited from a TiCl4 solution. The LSC and LSC-T thin films were investigated by electrochemical impedance spectroscopy, nano-probe Auger electron spectroscopy, and X-ray photoelectron spectroscopy (XPS), upon annealing at 420-530 °C in air up to about 90 hours. The oxygen exchange coefficient, k(q), on LSC-T cathodes was found to be up to 8 times higher than that on LSC cathodes at 530 °C and retained its stability. Sr-rich insulating particles formed at the surface of the annealed LSC and LSC-T films, but with significantly less coverage of such particles on the LSC-T. From this result, it appears that modification of the LSC surface with Ti reduces the segregation of the blocking Sr-rich particles at the surface, and a larger area on LSC surface (with a higher Sr doping level in the lattice) is available for the oxygen reduction reaction. The stabilization of the LSC surface through Ti-deposition can open a new route for designing surface modifications on perovskite oxide electrodes for high temperature electro- and thermo-chemical applications. PMID:26227310

  5. Accuracy potentials for large space antenna structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1980-01-01

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

  6. GEOSPATIAL DATA ACCURACY ASSESSMENT

    EPA Science Inventory

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

  7. Overlay accuracy fundamentals

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  8. Accuracy and consistency of modern elastomeric pumps.

    PubMed

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

    2014-01-01

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

  9. Interoceptive accuracy and panic.

    PubMed

    Zoellner, L A; Craske, M G

    1999-12-01

    Psychophysiological models of panic hypothesize that panickers focus attention on and become anxious about the physical sensations associated with panic. Attention on internal somatic cues has been labeled interoception. The present study examined the role of physiological arousal and subjective anxiety on interoceptive accuracy. Infrequent panickers and nonanxious participants participated in an initial baseline to examine overall interoceptive accuracy. Next, participants ingested caffeine, about which they received either safety or no safety information. Using a mental heartbeat tracking paradigm, participants' count of their heartbeats during specific time intervals were coded based on polygraph measures. Infrequent panickers were more accurate in the perception of their heartbeats than nonanxious participants. Changes in physiological arousal were not associated with increased accuracy on the heartbeat perception task. However, higher levels of self-reported anxiety were associated with superior performance. PMID:10596462

  10. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

  11. Optimal design of robot accuracy compensators

    SciTech Connect

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

    1993-12-01

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

  12. Accuracy analysis of automatic distortion correction

    NASA Astrophysics Data System (ADS)

    Kolecki, Jakub; Rzonca, Antoni

    2015-06-01

    The paper addresses the problem of the automatic distortion removal from images acquired with non-metric SLR camera equipped with prime lenses. From the photogrammetric point of view the following question arises: is the accuracy of distortion control data provided by the manufacturer for a certain lens model (not item) sufficient in order to achieve demanded accuracy? In order to obtain the reliable answer to the aforementioned problem the two kinds of tests were carried out for three lens models. Firstly the multi-variant camera calibration was conducted using the software providing full accuracy analysis. Secondly the accuracy analysis using check points took place. The check points were measured in the images resampled based on estimated distortion model or in distortion-free images simply acquired in the automatic distortion removal mode. The extensive conclusions regarding application of each calibration approach in practice are given. Finally the rules of applying automatic distortion removal in photogrammetric measurements are suggested.

  13. Accuracy of Pressure Sensitive Paint

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  14. High accuracy OMEGA timekeeping

    NASA Technical Reports Server (NTRS)

    Imbier, E. A.

    1982-01-01

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

  15. Towards Experimental Accuracy from the First Principles

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  16. Increasing Accuracy in Computed Inviscid Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Dyson, Roger

    2004-01-01

    A technique has been devised to increase the accuracy of computational simulations of flows of inviscid fluids by increasing the accuracy with which surface boundary conditions are represented. This technique is expected to be especially beneficial for computational aeroacoustics, wherein it enables proper accounting, not only for acoustic waves, but also for vorticity and entropy waves, at surfaces. Heretofore, inviscid nonlinear surface boundary conditions have been limited to third-order accuracy in time for stationary surfaces and to first-order accuracy in time for moving surfaces. For steady-state calculations, it may be possible to achieve higher accuracy in space, but high accuracy in time is needed for efficient simulation of multiscale unsteady flow phenomena. The present technique is the first surface treatment that provides the needed high accuracy through proper accounting of higher-order time derivatives. The present technique is founded on a method known in art as the Hermitian modified solution approximation (MESA) scheme. This is because high time accuracy at a surface depends upon, among other things, correction of the spatial cross-derivatives of flow variables, and many of these cross-derivatives are included explicitly on the computational grid in the MESA scheme. (Alternatively, a related method other than the MESA scheme could be used, as long as the method involves consistent application of the effects of the cross-derivatives.) While the mathematical derivation of the present technique is too lengthy and complex to fit within the space available for this article, the technique itself can be characterized in relatively simple terms: The technique involves correction of surface-normal spatial pressure derivatives at a boundary surface to satisfy the governing equations and the boundary conditions and thereby achieve arbitrarily high orders of time accuracy in special cases. The boundary conditions can now include a potentially infinite number

  17. Accuracy in Judgments of Aggressiveness

    PubMed Central

    Kenny, David A.; West, Tessa V.; Cillessen, Antonius H. N.; Coie, John D.; Dodge, Kenneth A.; Hubbard, Julie A.; Schwartz, David

    2009-01-01

    Perceivers are both accurate and biased in their understanding of others. Past research has distinguished between three types of accuracy: generalized accuracy, a perceiver’s accuracy about how a target interacts with others in general; perceiver accuracy, a perceiver’s view of others corresponding with how the perceiver is treated by others in general; and dyadic accuracy, a perceiver’s accuracy about a target when interacting with that target. Researchers have proposed that there should be more dyadic than other forms of accuracy among well-acquainted individuals because of the pragmatic utility of forecasting the behavior of interaction partners. We examined behavioral aggression among well-acquainted peers. A total of 116 9-year-old boys rated how aggressive their classmates were toward other classmates. Subsequently, 11 groups of 6 boys each interacted in play groups, during which observations of aggression were made. Analyses indicated strong generalized accuracy yet little dyadic and perceiver accuracy. PMID:17575243

  18. Design and performance of a new high accuracy combined small sample neutron/gamma detector

    SciTech Connect

    Menlove, H.; Davidson, D.; Verplancke, J.; Vermeulen, P.; Wagner, H.G.; Wellum, R.; Brandelise, B.; Mayer, K.

    1993-08-01

    This paper describes the design of an optimized combined neutron and gamma detector installed around a measurement well protruding from the floor of a glove box. The objective of this design was to achieve an overall accuracy for the plutonium element concentration in gram-sized samples of plutonium oxide powder approaching the {approximately}0.1--0.2% accuracies routinely achieved by inspectors` chemical analysis. The efficiency of the clam-shell neutron detector was increased and the flat response zone extended in axial and radial directions. The sample holder introduced from within the glove box was designed to form the upper reflector, while two graphite half-shells fitted around the thin neck of the high-resolution LEGE detector replaced the lower plug. The Institute for Reference Materials and Measurements (IRMM) in Geel prepared special plutonium oxide test samples whose plutonium concentration was determined to better than 0.05%. During a three week initial performance test in July 1992 at ITU Karlsruhe and in long term tests, it was established that the target accuracy can be achieved provided sufficient care is taken to assure the reproducibility of sample bottling and sample positioning. The paper presents and discusses the results of all test measurements.

  19. Design and performance of a new high accuracy combined small sample neutron/gamma detector

    SciTech Connect

    Menlove, H.; Davidson, D.; Verplancke, J.; Vermeulen, P.; Wagner, H.G.; Wellum, R.; Brandelise, B.; Mayer, K.

    1993-12-31

    This paper describes the design of an optimized combined neutron and gamma detector installed around a measurement well protruding from the floor of a glove box. The objective of this design was to achieve an overall accuracy for the plutonium element concentration in gram-sized samples of plutonium oxide powder approaching the {approximately}0.1--0.2% accuracies routinely achieved by inspectors` chemical analysis. The efficiency of the clam-shell neutron detector was increased and the flat response zone extended in axial and radial directions. The sample holder introduced from within the glove box was designed to form the upper reflector, while two graphite half-shells fitted around the thin neck of the high-resolution LEGe detector replaced the lower plug. The Institute for Reference Materials and Measurements (IRMM) in Geel prepared special plutonium oxide test samples whose plutonium concentration was determined to better than 0.05%. During a three week initial performance test in July 1992 at ITU Karlsruhe and in long term tests, it was established that the target accuracy can be achieved provided sufficient care is taken to assure the reproducibility of sample bottling and sample positioning. The paper presents and discusses the results of all test measurements.

  20. Accuracy of tablet splitting.

    PubMed

    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. PMID:9469693

  1. Affecting speed and accuracy in perception.

    PubMed

    Bocanegra, Bruno R

    2014-12-01

    An account of affective modulations in perceptual speed and accuracy (ASAP: Affecting Speed and Accuracy in Perception) is proposed and tested. This account assumes an emotion-induced inhibitory interaction between parallel channels in the visual system that modulates the onset latencies and response durations of visual signals. By trading off speed and accuracy between channels, this mechanism achieves (a) fast visuo-motor responding to course-grained information, and (b) accurate visuo-attentional selection of fine-grained information. ASAP gives a functional account of previously counterintuitive findings, and may be useful for explaining affective influences in both featural-level single-stimulus tasks and object-level multistimulus tasks. PMID:24853268

  2. Reticence, Accuracy and Efficacy

    NASA Astrophysics Data System (ADS)

    Oreskes, N.; Lewandowsky, S.

    2015-12-01

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

  3. Field Accuracy Test of Rpas Photogrammetry

    NASA Astrophysics Data System (ADS)

    Barry, P.; Coakley, R.

    2013-08-01

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

  4. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

  5. A method which can enhance the optical-centering accuracy

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-min; Zhang, Xue-jun; Dai, Yi-dan; Yu, Tao; Duan, Jia-you; Li, Hua

    2014-09-01

    Optical alignment machining is an effective method to ensure the co-axiality of optical system. The co-axiality accuracy is determined by optical-centering accuracy of single optical unit, which is determined by the rotating accuracy of lathe and the optical-centering judgment accuracy. When the rotating accuracy of 0.2um can be achieved, the leading error can be ignored. An axis-determination tool which is based on the principle of auto-collimation can be used to determine the only position of centerscope is designed. The only position is the position where the optical axis of centerscope is coincided with the rotating axis of the lathe. Also a new optical-centering judgment method is presented. A system which includes the axis-determination tool and the new optical-centering judgment method can enhance the optical-centering accuracy to 0.003mm.

  6. Landsat classification accuracy assessment procedures

    USGS Publications Warehouse

    Mead, R. R.; Szajgin, John

    1982-01-01

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

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

    PubMed Central

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

    2014-01-01

    RNA secondary structure modeling is a challenging problem, and recent successes have raised the standards for accuracy, consistency, and tractability. Large increases in accuracy have been achieved by including data on reactivity toward chemical probes: Incorporation of 1M7 SHAPE reactivity data into an mfold-class algorithm results in median accuracies for base pair prediction that exceed 90%. However, a few RNA structures are modeled with significantly lower accuracy. Here, we show that incorporating differential reactivities from the NMIA and 1M6 reagents—which detect noncanonical and tertiary interactions—into prediction algorithms results in highly accurate secondary structure models for RNAs that were previously shown to be difficult to model. For these RNAs, 93% of accepted canonical base pairs were recovered in SHAPE-directed models. Discrepancies between accepted and modeled structures were small and appear to reflect genuine structural differences. Three-reagent SHAPE-directed modeling scales concisely to structurally complex RNAs to resolve the in-solution secondary structure analysis problem for many classes of RNA. PMID:24742934

  8. Precision standoff guidance antenna accuracy evaluation

    NASA Astrophysics Data System (ADS)

    Irons, F. H.; Landesberg, M. M.

    1981-02-01

    This report presents a summary of work done to determine the inherent angular accuracy achievable with the guidance and control precision standoff guidance antenna. The antenna is a critical element in the anti-jam single station guidance program since its characteristics can limit the intrinsic location guidance accuracy. It was important to determine the extent to which high ratio beamsplitting results could be achieved repeatedly and what issues were involved with calibrating the antenna. The antenna accuracy has been found to be on the order of 0.006 deg. through the use of a straightforward lookup table concept. This corresponds to a cross range error of 21 m at a range of 200 km. This figure includes both pointing errors and off-axis estimation errors. It was found that the antenna off-boresight calibration is adequately represented by a straight line for each position plus a lookup table for pointing errors relative to broadside. In the event recalibration is required, it was found that only 1% of the model would need to be corrected.

  9. High accuracy in short ISS missions

    NASA Astrophysics Data System (ADS)

    Rüeger, J. M.

    1986-06-01

    Traditionally Inertial Surveying Systems ( ISS) are used for missions of 30 km to 100 km length. Today, a new type of ISS application is emanating from an increased need for survey control densification in urban areas often in connection with land information systems or cadastral surveys. The accuracy requirements of urban surveys are usually high. The loss in accuracy caused by the coordinate transfer between IMU and ground marks is investigated and an offsetting system based on electronic tacheometers is proposed. An offsetting system based on a Hewlett-Packard HP 3820A electronic tacheometer has been tested in Sydney (Australia) in connection with a vehicle mounted LITTON Auto-Surveyor System II. On missions over 750 m ( 8 stations, 25 minutes duration, 3.5 minute ZUPT intervals, mean offset distances 9 metres) accuracies of 37 mm (one sigma) in position and 8 mm in elevation were achieved. Some improvements to the LITTON Auto-Surveyor System II are suggested which would improve the accuracies even further.

  10. A Year of Exceptional Achievements FY 2008

    SciTech Connect

    devore, L; Chrzanowski, P

    2008-11-06

    2008 highlights: (1) Stockpile Stewardship and Complex Transformation - LLNL achieved scientific breakthroughs that explain some of the key 'unknowns' in nuclear weapons performance and are critical to developing the predictive science needed to ensure the safety, reliability, and security of the U.S. nuclear deterrent without nuclear testing. In addition, the National Ignition Facility (NIF) passed 99 percent completion, an LLNL supercomputer simulation won the 2007 Gordon Bell Prize, and a significant fraction of our inventory of special nuclear material was shipped to other sites in support of complex transformation. (2) National and Global Security - Laboratory researchers delivered insights, technologies, and operational capabilities that are helping to ensure national security and global stability. Of particular note, they developed advanced detection instruments that provide increased speed, accuracy, specificity, and resolution for identifying and characterizing biological, chemical, nuclear, and high-explosive threats. (3) Exceptional Science and Technology - The Laboratory continued its tradition of scientific excellence and technical innovation. LLNL scientists made significant contributions to Nobel Prize-winning work on climate change. LLNL also received three R&D 100 awards and six Nanotech 50 awards, and dozens of Laboratory scientists and engineers were recognized with professional awards. These honors provide valuable confirmation that peers and outside experts recognize the quality of our staff and our work. (4) Enhanced Business and Operations - A major thrust under LLNS is to make the Laboratory more efficient and cost competitive. We achieved roughly $75 million in cost savings for support activities through organizational changes, consolidation of services, improved governance structures and work processes, technology upgrades, and systems shared with Los Alamos National Laboratory. We realized nonlabor cost savings of $23 million. Severe

  11. Determining factors for the accuracy of DMRG in chemistry.

    PubMed

    Keller, Sebastian F; Reiher, Markus

    2014-01-01

    The Density Matrix Renormalization Group (DMRG) algorithm has been a rising star for the accurate ab initio exploration of Born-Oppenheimer potential energy surfaces in theoretical chemistry. However, owing to its iterative numerical nature, pitfalls that can affect the accuracy of DMRG energies need to be circumvented. Here, after a brief introduction into this quantum chemical method, we discuss criteria that determine the accuracy of DMRG calculations. PMID:24983596

  12. Meditation Experience Predicts Introspective Accuracy

    PubMed Central

    Fox, Kieran C. R.; Zakarauskas, Pierre; Dixon, Matt; Ellamil, Melissa; Thompson, Evan; Christoff, Kalina

    2012-01-01

    The accuracy of subjective reports, especially those involving introspection of one's own internal processes, remains unclear, and research has demonstrated large individual differences in introspective accuracy. It has been hypothesized that introspective accuracy may be heightened in persons who engage in meditation practices, due to the highly introspective nature of such practices. We undertook a preliminary exploration of this hypothesis, examining introspective accuracy in a cross-section of meditation practitioners (1–15,000 hrs experience). Introspective accuracy was assessed by comparing subjective reports of tactile sensitivity for each of 20 body regions during a ‘body-scanning’ meditation with averaged, objective measures of tactile sensitivity (mean size of body representation area in primary somatosensory cortex; two-point discrimination threshold) as reported in prior research. Expert meditators showed significantly better introspective accuracy than novices; overall meditation experience also significantly predicted individual introspective accuracy. These results suggest that long-term meditators provide more accurate introspective reports than novices. PMID:23049790

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

    SciTech Connect

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

    2007-04-27

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

  14. Assessment of the Thematic Accuracy of Land Cover Maps

    NASA Astrophysics Data System (ADS)

    Höhle, J.

    2015-08-01

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

  15. Noise limitations on monopulse accuracy in a multibeam antenna

    NASA Astrophysics Data System (ADS)

    Loraine, J.; Wallington, J. R.

    A multibeam system allowing target tracking using monopulse processing switched from beamset to beamset is considered. Attention is given to the accuracy of target angular position estimation. An analytical method is used to establish performance limits under low SNR conditions for a multibeam system. It is shown that, in order to achieve accuracies comparable to those of conventional monopulse systems, much higher SNRs are needed.

  16. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  17. ACCURACY LIMITATIONS IN LONG TRACE PROFILOMETRY.

    SciTech Connect

    TAKACS,P.Z.; QIAN,S.

    2003-08-25

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

  18. Accuracy Limitations in Long-Trace Profilometry

    SciTech Connect

    Takacs, Peter Z.; Qian Shinan

    2004-05-12

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

  19. Accuracy assessment system and operation

    NASA Technical Reports Server (NTRS)

    Pitts, D. E.; Houston, A. G.; Badhwar, G.; Bender, M. J.; Rader, M. L.; Eppler, W. G.; Ahlers, C. W.; White, W. P.; Vela, R. R.; Hsu, E. M. (Principal Investigator)

    1979-01-01

    The accuracy and reliability of LACIE estimates of wheat production, area, and yield is determined at regular intervals throughout the year by the accuracy assessment subsystem which also investigates the various LACIE error sources, quantifies the errors, and relates then to their causes. Timely feedback of these error evaluations to the LACIE project was the only mechanism by which improvements in the crop estimation system could be made during the short 3 year experiment.

  20. Evaluating LANDSAT wildland classification accuracies

    NASA Technical Reports Server (NTRS)

    Toll, D. L.

    1980-01-01

    Procedures to evaluate the accuracy of LANDSAT derived wildland cover classifications are described. The evaluation procedures include: (1) implementing a stratified random sample for obtaining unbiased verification data; (2) performing area by area comparisons between verification and LANDSAT data for both heterogeneous and homogeneous fields; (3) providing overall and individual classification accuracies with confidence limits; (4) displaying results within contingency tables for analysis of confusion between classes; and (5) quantifying the amount of information (bits/square kilometer) conveyed in the LANDSAT classification.

  1. The accuracy of automatic tracking

    NASA Technical Reports Server (NTRS)

    Kastrov, V. V.

    1974-01-01

    It has been generally assumed that tracking accuracy changes similarly to the rate of change of the curve of the measurement conversion. The problem that internal noise increases along with the signals processed by the tracking device and that tracking accuracy thus drops were considered. The main prerequisite for solution is consideration of the dependences of the output signal of the tracking device sensor not only on the measured parameter but on the signal itself.

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

    ERIC Educational Resources Information Center

    Haberman, Shelby J.

    2010-01-01

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

  3. Solving Nonlinear Euler Equations with Arbitrary Accuracy

    NASA Technical Reports Server (NTRS)

    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.

  4. Accuracy in optical overlay metrology

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  6. Comparing Science Achievement Constructs: Targeted and Achieved

    ERIC Educational Resources Information Center

    Ferrara, Steve; Duncan, Teresa

    2011-01-01

    This article illustrates how test specifications based solely on academic content standards, without attention to other cognitive skills and item response demands, can fall short of their targeted constructs. First, the authors inductively describe the science achievement construct represented by a statewide sixth-grade science proficiency test.…

  7. Current Concept of Geometrical Accuracy

    NASA Astrophysics Data System (ADS)

    Görög, Augustín; Görögová, Ingrid

    2014-06-01

    Within the solving VEGA 1/0615/12 research project "Influence of 5-axis grinding parameters on the shank cutteŕs geometric accuracy", the research team will measure and evaluate geometrical accuracy of the produced parts. They will use the contemporary measurement technology (for example the optical 3D scanners). During the past few years, significant changes have occurred in the field of geometrical accuracy. The objective of this contribution is to analyse the current standards in the field of geometric tolerance. It is necessary to bring an overview of the basic concepts and definitions in the field. It will prevent the use of outdated and invalidated terms and definitions in the field. The knowledge presented in the contribution will provide the new perspective of the measurement that will be evaluated according to the current standards.

  8. Varieties of Achievement Motivation.

    ERIC Educational Resources Information Center

    Kukla, Andre; Scher, Hal

    1986-01-01

    A recent article by Nicholls on achievement motivation is criticized on three points: (1) definitions of achievement motives are ambiguous; (2) behavioral consequences predicted do not follow from explicit theoretical assumptions; and (3) Nicholls's account of the relation between his theory and other achievement theories is factually incorrect.…

  9. Motivation and School Achievement.

    ERIC Educational Resources Information Center

    Maehr, Martin L.; Archer, Jennifer

    Addressing the question, "What can be done to promote school achievement?", this paper summarizes the literature on motivation relating to classroom achievement and school effectiveness. Particular attention is given to how values, ideology, and various cultural patterns impinge on classroom performance and serve to enhance motivation to achieve.…

  10. Mobility and Reading Achievement.

    ERIC Educational Resources Information Center

    Waters, Theresa Z.

    A study examined the effect of geographic mobility on elementary school students' achievement. Although such mobility, which requires students to make multiple moves among schools, can have a negative impact on academic achievement, the hypothesis for the study was that it was not a determining factor in reading achievement test scores. Subjects…

  11. PASS and Reading Achievement.

    ERIC Educational Resources Information Center

    Kirby, John R.

    Two studies examined the effectiveness of the PASS (Planning, Attention, Simultaneous, and Successive cognitive processes) theory of intelligence in predicting reading achievement scores of normally achieving children and distinguishing children with reading disabilities from normally achieving children. The first study dealt with predicting…

  12. Accuracy and Precision of an IGRT Solution

    SciTech Connect

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

    2009-07-01

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

  13. Accuracy and precision of an IGRT solution.

    PubMed

    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

  14. ACCURACY AND TRACE ORGANIC ANALYSES

    EPA Science Inventory

    Accuracy in trace organic analysis presents a formidable problem to the residue chemist. He is confronted with the analysis of a large number and variety of compounds present in a multiplicity of substrates at levels as low as parts-per-trillion. At these levels, collection, isol...

  15. The hidden KPI registration accuracy.

    PubMed

    Shorrosh, Paul

    2011-09-01

    Determining the registration accuracy rate is fundamental to improving revenue cycle key performance indicators. A registration quality assurance (QA) process allows errors to be corrected before bills are sent and helps registrars learn from their mistakes. Tools are available to help patient access staff who perform registration QA manually. PMID:21923052

  16. Psychology Textbooks: Examining Their Accuracy

    ERIC Educational Resources Information Center

    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…

  17. A Survey of Reading Achievement in a Secondary School Population.

    ERIC Educational Resources Information Center

    Moodie, Allan G.

    Reading achievement of students from open plan and traditional elementary classes were compared in three areas; speed and accuracy, vocabulary, and comprehension. The first evaluation (Grade 7) indicated that the mean score of the speed and accuracy scale was significantly lower for "open-area" students than for traditional pupils. Score…

  18. Teachers' Judgements of Students' Foreign-Language Achievement

    ERIC Educational Resources Information Center

    Zhu, Mingjing; Urhahne, Detlef

    2015-01-01

    Numerous studies have been conducted on the accuracy of teacher judgement in different educational areas such as mathematics, language arts and reading. Teacher judgement of students' foreign-language achievement, however, has been rarely investigated. The study aimed to examine the accuracy of teacher judgement of students' foreign-language…

  19. Improved accuracies for satellite tracking

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  20. MAPPING SPATIAL THEMATIC ACCURACY WITH FUZZY SETS

    EPA Science Inventory

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

  1. Improving the Accuracy of Self-Corrected Mathematics Homework.

    ERIC Educational Resources Information Center

    Miller, Tracy L.; And Others

    1993-01-01

    A study investigated the effect of reward on sixth graders' self-correction inaccuracy and monitored the effect of improved self-correction on mathematics homework achievement. There was a low baseline rate of student self-correction inaccuracy. Offering a reward for improved accuracy caused the rate of inaccuracy to decrease significantly.…

  2. Improving Homework Accuracy: Interdependent Group Contingencies and Randomized Components

    ERIC Educational Resources Information Center

    Reinhardt, Danielle; Theodore, Lea A.; Bray, Melissa A.; Kehle, Thomas J.

    2009-01-01

    Homework is an often employed teaching strategy that has strong positive effects on academic achievement across grade levels, content areas, and student ability levels. To maximize academic learning, accuracy of homework should be addressed. The present investigation employed a multiple-baseline design across academic behaviors to examine the…

  3. NMRDSP: an accurate prediction of protein shape strings from NMR chemical shifts and sequence data.

    PubMed

    Mao, Wusong; Cong, Peisheng; Wang, Zhiheng; Lu, Longjian; Zhu, Zhongliang; Li, Tonghua

    2013-01-01

    Shape string is structural sequence and is an extremely important structure representation of protein backbone conformations. Nuclear magnetic resonance chemical shifts give a strong correlation with the local protein structure, and are exploited to predict protein structures in conjunction with computational approaches. Here we demonstrate a novel approach, NMRDSP, which can accurately predict the protein shape string based on nuclear magnetic resonance chemical shifts and structural profiles obtained from sequence data. The NMRDSP uses six chemical shifts (HA, H, N, CA, CB and C) and eight elements of structure profiles as features, a non-redundant set (1,003 entries) as the training set, and a conditional random field as a classification algorithm. For an independent testing set (203 entries), we achieved an accuracy of 75.8% for S8 (the eight states accuracy) and 87.8% for S3 (the three states accuracy). This is higher than only using chemical shifts or sequence data, and confirms that the chemical shift and the structure profile are significant features for shape string prediction and their combination prominently improves the accuracy of the predictor. We have constructed the NMRDSP web server and believe it could be employed to provide a solid platform to predict other protein structures and functions. The NMRDSP web server is freely available at http://cal.tongji.edu.cn/NMRDSP/index.jsp. PMID:24376713

  4. NMRDSP: An Accurate Prediction of Protein Shape Strings from NMR Chemical Shifts and Sequence Data

    PubMed Central

    Mao, Wusong; Cong, Peisheng; Wang, Zhiheng; Lu, Longjian; Zhu, Zhongliang; Li, Tonghua

    2013-01-01

    Shape string is structural sequence and is an extremely important structure representation of protein backbone conformations. Nuclear magnetic resonance chemical shifts give a strong correlation with the local protein structure, and are exploited to predict protein structures in conjunction with computational approaches. Here we demonstrate a novel approach, NMRDSP, which can accurately predict the protein shape string based on nuclear magnetic resonance chemical shifts and structural profiles obtained from sequence data. The NMRDSP uses six chemical shifts (HA, H, N, CA, CB and C) and eight elements of structure profiles as features, a non-redundant set (1,003 entries) as the training set, and a conditional random field as a classification algorithm. For an independent testing set (203 entries), we achieved an accuracy of 75.8% for S8 (the eight states accuracy) and 87.8% for S3 (the three states accuracy). This is higher than only using chemical shifts or sequence data, and confirms that the chemical shift and the structure profile are significant features for shape string prediction and their combination prominently improves the accuracy of the predictor. We have constructed the NMRDSP web server and believe it could be employed to provide a solid platform to predict other protein structures and functions. The NMRDSP web server is freely available at http://cal.tongji.edu.cn/NMRDSP/index.jsp. PMID:24376713

  5. The Chemical Heritage Foundation

    NASA Astrophysics Data System (ADS)

    Orna, Mary Virginia

    1998-04-01

    This first in a series of articles on the Chemical Heritage Foundation will outline a brief history of the foundation and give an overview of its present programs, with emphasis on the Othmer Library of Chemical History. The Chemical Heritage Foundation (CHF) is a unique asset and unique partnership of the chemical community. It had its origins in a simple written agreement some 15 years ago, in January 1982. CHF's mission of recording, preserving, and making known the heritage of chemical achievement does not reflect the concerns of the chemical corporations or of anyone directly concerned with the "image" or economic and political future of the chemical sciences. Rather, it was an idea of academics and professional scientists. Thus it was appropriate that the three founding organizations were the American Chemical Society, the American Institute of Chemical Engineers and the University of Pennsylvania.

  6. Improved precision and accuracy in quantifying plutonium isotope ratios by RIMS

    SciTech Connect

    Isselhardt, B. H.; Savina, M. R.; Kucher, A.; Gates, S. D.; Knight, K. B.; Hutcheon, I. D.

    2015-09-01

    Resonance ionization mass spectrometry (RIMS) holds the promise of rapid, isobar-free quantification of actinide isotope ratios in as-received materials (i.e. not chemically purified). Recent progress in achieving this potential using two Pu test materials is presented. RIMS measurements were conducted multiple times over a period of two months on two different Pu solutions deposited on metal surfaces. Measurements were bracketed with a Pu isotopic standard, and yielded absolute accuracies of the measured 240Pu/239Pu ratios of 0.7% and 0.58%, with precisions (95% confidence intervals) of 1.49% and 0.91%. In conclusion, the minor isotope 238Pu was also quantified despite the presence of a significant quantity of 238U in the samples.

  7. Improved precision and accuracy in quantifying plutonium isotope ratios by RIMS

    DOE PAGESBeta

    Isselhardt, B. H.; Savina, M. R.; Kucher, A.; Gates, S. D.; Knight, K. B.; Hutcheon, I. D.

    2015-09-01

    Resonance ionization mass spectrometry (RIMS) holds the promise of rapid, isobar-free quantification of actinide isotope ratios in as-received materials (i.e. not chemically purified). Recent progress in achieving this potential using two Pu test materials is presented. RIMS measurements were conducted multiple times over a period of two months on two different Pu solutions deposited on metal surfaces. Measurements were bracketed with a Pu isotopic standard, and yielded absolute accuracies of the measured 240Pu/239Pu ratios of 0.7% and 0.58%, with precisions (95% confidence intervals) of 1.49% and 0.91%. In conclusion, the minor isotope 238Pu was also quantified despite the presence ofmore » a significant quantity of 238U in the samples.« less

  8. A high accuracy sun sensor

    NASA Astrophysics Data System (ADS)

    Bokhove, H.

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

  9. Municipal water consumption forecast accuracy

    NASA Astrophysics Data System (ADS)

    Fullerton, Thomas M.; Molina, Angel L.

    2010-06-01

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

  10. Heritability of Creative Achievement

    ERIC Educational Resources Information Center

    Piffer, Davide; Hur, Yoon-Mi

    2014-01-01

    Although creative achievement is a subject of much attention to lay people, the origin of individual differences in creative accomplishments remain poorly understood. This study examined genetic and environmental influences on creative achievement in an adult sample of 338 twins (mean age = 26.3 years; SD = 6.6 years). Twins completed the Creative…

  11. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  12. States Address Achievement Gaps.

    ERIC Educational Resources Information Center

    Christie, Kathy

    2002-01-01

    Summarizes 2 state initiatives to address the achievement gap: North Carolina's report by the Advisory Commission on Raising Achievement and Closing Gaps, containing an 11-point strategy, and Kentucky's legislation putting in place 10 specific processes. The North Carolina report is available at www.dpi.state.nc.us.closingthegap; Kentucky's…

  13. Wechsler Individual Achievement Test.

    ERIC Educational Resources Information Center

    Taylor, Ronald L.

    1999-01-01

    This article describes the Wechsler Individual Achievement Test, a comprehensive measure of achievement for individuals in grades K-12. Eight subtests assess mathematics reasoning, spelling, reading comprehension, numerical operations, listening comprehension, oral expression, and written expression. Its administration, standardization,…

  14. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  15. Achievement Test Program.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Trade and Industrial Education Service.

    The Ohio Trade and Industrial Education Achievement Test battery is comprised of seven basic achievement tests: Machine Trades, Automotive Mechanics, Basic Electricity, Basic Electronics, Mechanical Drafting, Printing, and Sheet Metal. The tests were developed by subject matter committees and specialists in testing and research. The Ohio Trade and…

  16. General Achievement Trends: Maryland

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  17. General Achievement Trends: Arkansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  18. General Achievement Trends: Idaho

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  19. General Achievement Trends: Nebraska

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  20. General Achievement Trends: Colorado

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  1. General Achievement Trends: Iowa

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  2. General Achievement Trends: Hawaii

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  3. General Achievement Trends: Kentucky

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  4. General Achievement Trends: Florida

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  5. General Achievement Trends: Texas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  6. General Achievement Trends: Oregon

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  7. General Achievement Trends: Virginia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  8. Honoring Student Achievement

    ERIC Educational Resources Information Center

    Education Digest: Essential Readings Condensed for Quick Review, 2004

    2004-01-01

    Is the concept of "honor roll" obsolete? The honor roll has always been a way for schools to recognize the academic achievement of their students. But does it motivate students? In this article, several elementary school principals share their views about honoring student achievement. Among others, Virginia principal Nancy Moga said that students…

  9. Aiming at Achievement.

    ERIC Educational Resources Information Center

    Martinez, Paul

    The Raising Quality and Achievement Program is a 3-year initiative to support further education (FE) colleges in the United Kingdom in their drive to improve students' achievement and the quality of provision. The program offers the following: (1) quality information and advice; (2) onsite support for individual colleges; (3) help with…

  10. Achieving Perspective Transformation.

    ERIC Educational Resources Information Center

    Nowak, Jens

    Perspective transformation is a consciously achieved state in which the individual's perspective on life is transformed. The new perspective serves as a vantage point for life's actions and interactions, affecting the way life is lived. Three conditions are basic to achieving perspective transformation: (1) "feeling" experience, i.e., getting in…

  11. Achieving Public Schools

    ERIC Educational Resources Information Center

    Abowitz, Kathleen Knight

    2011-01-01

    Public schools are functionally provided through structural arrangements such as government funding, but public schools are achieved in substance, in part, through local governance. In this essay, Kathleen Knight Abowitz explains the bifocal nature of achieving public schools; that is, that schools are both subject to the unitary Public compact of…

  12. General Achievement Trends: Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  13. Achievement-Based Resourcing.

    ERIC Educational Resources Information Center

    Fletcher, Mike; And Others

    1992-01-01

    This collection of seven articles examines achievement-based resourcing (ABR), the concept that the funding of educational institutions should be linked to their success in promoting student achievement, with a focus on the application of ABR to postsecondary education in the United Kingdom. The articles include: (1) "Introduction" (Mick…

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  15. [Achievement of therapeutic objectives].

    PubMed

    Mantilla, Teresa

    2014-07-01

    Therapeutic objectives for patients with atherogenic dyslipidemia are achieved by improving patient compliance and adherence. Clinical practice guidelines address the importance of treatment compliance for achieving objectives. The combination of a fixed dose of pravastatin and fenofibrate increases the adherence by simplifying the drug regimen and reducing the number of daily doses. The good tolerance, the cost of the combination and the possibility of adjusting the administration to the patient's lifestyle helps achieve the objectives for these patients with high cardiovascular risk. PMID:25043543

  16. Measuring Diagnoses: ICD Code Accuracy

    PubMed Central

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

    2005-01-01

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

  17. Predicting Achievement and Motivation.

    ERIC Educational Resources Information Center

    Uguroglu, Margaret; Walberg, Herbert J.

    1986-01-01

    Motivation and nine other factors were measured for 970 students in grades five through eight in a study of factors predicting achievement and predicting motivation. Results are discussed. (Author/MT)

  18. Attractiveness and School Achievement

    ERIC Educational Resources Information Center

    Salvia, John; And Others

    1977-01-01

    The purpose of this study was to ascertain the relationship between rated attractiveness and two measures of school performance. Attractive children received significantly higher report cards and, to some degree, higher achievement test scores than their unattractive peers. (Author)

  19. Student Achievement and Motivation

    ERIC Educational Resources Information Center

    Flammer, Gordon H.; Mecham, Robert C.

    1974-01-01

    Compares the lecture and self-paced methods of instruction on the basis of student motivation and achieveme nt, comparing motivating and demotivating factors in each, and their potential for motivation and achievement. (Authors/JR)

  20. Atomic Resolution Imaging and Quantification of Chemical Functionality of Surfaces

    SciTech Connect

    Schwarz, Udo

    2014-12-10

    The work carried out from 2006-2014 under DoE support was targeted at developing new approaches to the atomic-scale characterization of surfaces that include species-selective imaging and an ability to quantify chemical surface interactions with site-specific accuracy. The newly established methods were subsequently applied to gain insight into the local chemical interactions that govern the catalytic properties of model catalysts of interest to DoE. The foundation of our work was the development of three-dimensional atomic force microscopy (3D-AFM), a new measurement mode that allows the mapping of the complete surface force and energy fields with picometer resolution in space (x, y, and z) and piconewton/millielectron volts in force/energy. From this experimental platform, we further expanded by adding the simultaneous recording of tunneling current (3D-AFM/STM) using chemically well-defined tips. Through comparison with simulations, we were able to achieve precise quantification and assignment of local chemical interactions to exact positions within the lattice. During the course of the project, the novel techniques were applied to surface-oxidized copper, titanium dioxide, and silicon oxide. On these materials, defect-induced changes to the chemical surface reactivity and electronic charge density were characterized with site-specific accuracy.

  1. A high-order numerical algorithm for DNS of low-Mach-number reactive flows with detailed chemistry and quasi-spectral accuracy

    NASA Astrophysics Data System (ADS)

    Motheau, E.; Abraham, J.

    2016-05-01

    A novel and efficient algorithm is presented in this paper to deal with DNS of turbulent reacting flows under the low-Mach-number assumption, with detailed chemistry and a quasi-spectral accuracy. The temporal integration of the equations relies on an operating-split strategy, where chemical reactions are solved implicitly with a stiff solver and the convection-diffusion operators are solved with a Runge-Kutta-Chebyshev method. The spatial discretisation is performed with high-order compact schemes, and a FFT based constant-coefficient spectral solver is employed to solve a variable-coefficient Poisson equation. The numerical implementation takes advantage of the 2DECOMP&FFT libraries developed by [1], which are based on a pencil decomposition method of the domain and are proven to be computationally very efficient. An enhanced pressure-correction method is proposed to speed up the achievement of machine precision accuracy. It is demonstrated that a second-order accuracy is reached in time, while the spatial accuracy ranges from fourth-order to sixth-order depending on the set of imposed boundary conditions. The software developed to implement the present algorithm is called HOLOMAC, and its numerical efficiency opens the way to deal with DNS of reacting flows to understand complex turbulent and chemical phenomena in flames.

  2. Tracking accuracy for Leosat-Geosat laser links

    NASA Astrophysics Data System (ADS)

    Seshamani, Ramani; Rao, D. V. B.; Alex, T. K.; Jain, Y. K.

    1989-06-01

    A tracking accuracy of 1 microrad is required for the achievement of Leosat-Geosat laser communications links, entailing exceptionally accurate alignment between transmitter and receiver as well as point-ahead capability. The pointing and acquisition procedure would involve the two optical system/telescope units to be pointed toward each other with an attitude accuracy smaller than the position uncertainty; a spatial-scam operation by the Leosat's narrow beam, and subsequently by the Geosat's would have to be conducted before acquisition is completed, allowing switching from acquisition to tracking mode.

  3. Accuracy testing of steel and electric groundwater-level measuring tapes: Test method and in-service tape accuracy

    USGS Publications Warehouse

    Fulford, Janice M.; Clayton, Christopher S.

    2015-01-01

    The calibration device and proposed method were used to calibrate a sample of in-service USGS steel and electric groundwater tapes. The sample of in-service groundwater steel tapes were in relatively good condition. All steel tapes, except one, were accurate to ±0.01 ft per 100 ft over their entire length. One steel tape, which had obvious damage in the first hundred feet, was marginally outside the accuracy of ±0.01 ft per 100 ft by 0.001 ft. The sample of in-service groundwater-level electric tapes were in a range of conditions—from like new, with cosmetic damage, to nonfunctional. The in-service electric tapes did not meet the USGS accuracy recommendation of ±0.01 ft. In-service electric tapes, except for the nonfunctional tape, were accurate to about ±0.03 ft per 100 ft. A comparison of new with in-service electric tapes found that steel-core electric tapes maintained their length and accuracy better than electric tapes without a steel core. The in-service steel tapes could be used as is and achieve USGS accuracy recommendations for groundwater-level measurements. The in-service electric tapes require tape corrections to achieve USGS accuracy recommendations for groundwater-level measurement.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  5. High accuracy time transfer synchronization

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  6. Knowledge discovery by accuracy maximization

    PubMed Central

    Cacciatore, Stefano; Luchinat, Claudio; Tenori, Leonardo

    2014-01-01

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

  7. Classification Accuracy Increase Using Multisensor Data Fusion

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  8. Increasing Accuracy in Environmental Measurements

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  9. Accuracy of numerically produced compensators.

    PubMed

    Thompson, H; Evans, M D; Fallone, B G

    1999-01-01

    A feasibility study is performed to assess the utility of a computer numerically controlled (CNC) mill to produce compensating filters for conventional clinical use and for the delivery of intensity-modulated beams. A computer aided machining (CAM) software is used to assist in the design and construction of such filters. Geometric measurements of stepped and wedged surfaces are made to examine the accuracy of surface milling. Molds are milled and filled with molten alloy to produce filters, and both the molds and filters are examined for consistency and accuracy. Results show that the deviation of the filter surfaces from design does not exceed 1.5%. The effective attenuation coefficient is measured for CadFree, a cadmium-free alloy, in a 6 MV photon beam. The effective attenuation coefficients at the depth of maximum dose (1.5 cm) and at 10 cm in solid water phantom are found to be 0.546 cm-1 and 0.522 cm-1, respectively. Further attenuation measurements are made with Cerrobend to assess the variations of the effective attenuation coefficient with field size and source-surface distance. The ability of the CNC mill to accurately produce surfaces is verified with dose profile measurements in a 6 MV photon beam. The test phantom is composed of a 10 degrees polystyrene wedge and a 30 degrees polystyrene wedge, presenting both a sharp discontinuity and sloped surfaces. Dose profiles, measured at the depth of compensation (10 cm) beneath the test phantom and beneath a flat phantom, are compared to those produced by a commercial treatment planning system. Agreement between measured and predicted profiles is within 2%, indicating the viability of the system for filter production. PMID:10100166

  10. High Accuracy Wavelength Calibration For A Scanning Visible Spectrometer

    SciTech Connect

    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.

  11. High accuracy wavelength calibration for a scanning visible spectrometer.

    PubMed

    Scotti, Filippo; Bell, Ronald E

    2010-10-01

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies ≤0.2 Å. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of ∼0.25 Å has been demonstrated. With the addition of a high resolution (0.075 arc  sec) optical encoder on the grating stage, greater precision (∼0.005 Å) is possible, allowing absolute velocity measurements within ∼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. PMID:21033925

  12. The predictive accuracy of intertemporal-choice models.

    PubMed

    Arfer, Kodi B; Luhmann, Christian C

    2015-05-01

    How do people choose between a smaller reward available sooner and a larger reward available later? Past research has evaluated models of intertemporal choice by measuring goodness of fit or identifying which decision-making anomalies they can accommodate. An alternative criterion for model quality, which is partly antithetical to these standard criteria, is predictive accuracy. We used cross-validation to examine how well 10 models of intertemporal choice could predict behaviour in a 100-trial binary-decision task. Many models achieved the apparent ceiling of 85% accuracy, even with smaller training sets. When noise was added to the training set, however, a simple logistic-regression model we call the difference model performed particularly well. In many situations, between-model differences in predictive accuracy may be small, contrary to long-standing controversy over the modelling question in research on intertemporal choice, but the simplicity and robustness of the difference model recommend it to future use. PMID:25773127

  13. Improving Accuracy of Image Classification Using GIS

    NASA Astrophysics Data System (ADS)

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

    The Remote Sensing signal which reaches sensor on-board the satellite is the complex aggregation of signals (in agriculture field for example) from soil (with all its variations such as colour, texture, particle size, clay content, organic and nutrition content, inorganic content, water content etc.), plant (height, architecture, leaf area index, mean canopy inclination etc.), canopy closure status and atmospheric effects, and from this we want to find say, characteristics of vegetation. If sensor on- board the satellite makes measurements in n-bands (n of n*1 dimension) and number of classes in an image are c (f of c*1 dimension), then considering linear mixture modeling the pixel classification problem could be written as n = m* f +, where m is the transformation matrix of (n*c) dimension and therepresents the error vector (noise). The problem is to estimate f by inverting the above equation and the possible solutions for such problem are many. Thus, getting back individual classes from satellite data is an ill-posed inverse problem for which unique solution is not feasible and this puts limit to the obtainable classification accuracy. Maximum Likelihood (ML) is the constraint mostly practiced in solving such a situation which suffers from the handicaps of assumed Gaussian distribution and random nature of pixels (in-fact there is high auto-correlation among the pixels of a specific class and further high auto-correlation among the pixels in sub- classes where the homogeneity would be high among pixels). Due to this, achieving of very high accuracy in the classification of remote sensing images is not a straight proposition. With the availability of the GIS for the area under study (i) a priori probability for different classes could be assigned to ML classifier in more realistic terms and (ii) the purity of training sets for different thematic classes could be better ascertained. To what extent this could improve the accuracy of classification in ML classifier

  14. BIOMONITORING TO ACHIEVE CONTROL OF TOXIC EFFLUENTS

    EPA Science Inventory

    This 48 - page Technology Transfer Report provides a case study of how water quality-based toxicity control procedures can be combined with chemical analyses and biological stream surveys to achieve more effective water pollution control. t describes how regulatory agencies used ...

  15. Chemical Emergencies

    MedlinePlus

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  16. Awareness of Peers' Judgments of Oneself: Accuracy and Process of Metaperception

    ERIC Educational Resources Information Center

    Malloy, Thomas E.; Albright, Linda; Scarpati, Stan

    2007-01-01

    This research focused on children's awareness of peers' social judgments of them, age differences in accuracy attained, and the process by which accuracy is achieved. Children were accurately aware of peers' perceptions of them on behavioral, social status, and ability dimensions in Grades 1 through 6. Older children were more accurate than…

  17. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

    Recent research on the nature of achievement motivation is reviewed. A three-factor model of intrinsic motives is presented and related to various criteria of performance, job satisfaction and leisure activities. The relationships between intrinsic and extrinsic motives are discussed. Needed areas for future research are described.

  18. Achieving health care affordability.

    PubMed

    Payson, Norman C

    2002-10-01

    Not all plans are jumping headlong into the consumer-centric arena. In this article, the CEO of Oxford Health Plans discusses how advanced managed care can achieve what other consumer-centric programs seek to do--provide affordable, quality health care. PMID:12391815

  19. Issues in Achievement Testing.

    ERIC Educational Resources Information Center

    Baker, Eva L.

    This booklet is intended to help school personnel, parents, students, and members of the community understand concepts and research relating to achievement testing in public schools. The paper's sections include: (1) test use with direct effects on students (test of certification, selection, and placement); (2) test use with indirect effects on…

  20. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    While it is generally agreed that peace is desirable, there are barriers to achieving a peaceful world. These barriers are classified into three major areas: (1) an erroneous view of human nature; (2) injustice; and (3) fear of world unity. In a discussion of these barriers, it is noted that although the consciousness and conscience of the world…

  1. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

    National learning and skills policy aims both to build economic prosperity and to achieve social justice. Participation in higher education (HE) has the potential to contribute substantially to both aims. That is why the Campaign for Learning has supported the ambition to increase the proportion of the working-age population with a Level 4…

  2. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

    Deary, Ian J.; Strand, Steve; Smith, Pauline; Fernandes, Cres

    2007-01-01

    This 5-year prospective longitudinal study of 70,000+ English children examined the association between psychometric intelligence at age 11 years and educational achievement in national examinations in 25 academic subjects at age 16. The correlation between a latent intelligence trait (Spearman's "g"from CAT2E) and a latent trait of educational…

  3. SALT and Spelling Achievement.

    ERIC Educational Resources Information Center

    Nelson, Joan

    A study investigated the effects of suggestopedic accelerative learning and teaching (SALT) on the spelling achievement, attitudes toward school, and memory skills of fourth-grade students. Subjects were 20 male and 28 female students from two self-contained classrooms at Kennedy Elementary School in Rexburg, Idaho. The control classroom and the…

  4. NCLB: Achievement Robin Hood?

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2008-01-01

    In his "Wall Street Journal" op-ed on the 25th of anniversary of "A Nation At Risk", former assistant secretary of education Chester E. Finn Jr. applauded the report for turning U.S. education away from equality and toward achievement. It was not surprising, then, that in mid-2008, Finn arranged a conference to examine the potential "Robin Hood…

  5. INTELLIGENCE, PERSONALITY AND ACHIEVEMENT.

    ERIC Educational Resources Information Center

    MUIR, R.C.; AND OTHERS

    A LONGITUDINAL DEVELOPMENTAL STUDY OF A GROUP OF MIDDLE CLASS CHILDREN IS DESCRIBED, WITH EMPHASIS ON A SEGMENT OF THE RESEARCH INVESTIGATING THE RELATIONSHIP OF ACHIEVEMENT, INTELLIGENCE, AND EMOTIONAL DISTURBANCE. THE SUBJECTS WERE 105 CHILDREN AGED FIVE TO 6.3 ATTENDING TWO SCHOOLS IN MONTREAL. EACH CHILD WAS ASSESSED IN THE AREAS OF…

  6. School Students' Science Achievement

    ERIC Educational Resources Information Center

    Shymansky, James; Wang, Tzu-Ling; Annetta, Leonard; Everett, Susan; Yore, Larry D.

    2013-01-01

    This paper is a report of the impact of an externally funded, multiyear systemic reform project on students' science achievement on a modified version of the Third International Mathematics and Science Study (TIMSS) test in 33 small, rural school districts in two Midwest states. The systemic reform effort utilized a cascading leadership strategy…

  7. Advancing Student Achievement

    ERIC Educational Resources Information Center

    Walberg, Herbert J.

    2010-01-01

    For the last half century, higher spending and many modern reforms have failed to raise the achievement of students in the United States to the levels of other economically advanced countries. A possible explanation, says Herbert Walberg, is that much current education theory is ill informed about scientific psychology, often drawing on fads and…

  8. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to…

  9. Increasing Male Academic Achievement

    ERIC Educational Resources Information Center

    Jackson, Barbara Talbert

    2008-01-01

    The No Child Left Behind legislation has brought greater attention to the academic performance of American youth. Its emphasis on student achievement requires a closer analysis of assessment data by school districts. To address the findings, educators must seek strategies to remedy failing results. In a mid-Atlantic district of the Unites States,…

  10. Setting and Achieving Objectives.

    ERIC Educational Resources Information Center

    Knoop, Robert

    1986-01-01

    Provides basic guidelines which school officials and school boards may find helpful in negotiating, establishing, and managing objectives. Discusses characteristics of good objectives, specific and directional objectives, multiple objectives, participation in setting objectives, feedback on goal process and achievement, and managing a school…

  11. Schools Achieving Gender Equity.

    ERIC Educational Resources Information Center

    Revis, Emma

    This guide is designed to assist teachers presenting the Schools Achieving Gender Equity (SAGE) curriculum for vocational education students, which was developed to align gender equity concepts with the Kentucky Education Reform Act (KERA). Included in the guide are lesson plans for classes on the following topics: legal issues of gender equity,…

  12. Iowa Women of Achievement.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This issue of the Goldfinch highlights some of Iowa's 20th century women of achievement. These women have devoted their lives to working for human rights, education, equality, and individual rights. They come from the worlds of politics, art, music, education, sports, business, entertainment, and social work. They represent Native Americans,…

  13. Achievements or Disasters?

    ERIC Educational Resources Information Center

    Goodwin, MacArthur

    2000-01-01

    Focuses on policy issues that have affected arts education in the twentieth century, such as: interest in discipline-based arts education, influence of national arts associations, and national standards and coordinated assessment. States that whether the policy decisions are viewed as achievements or disasters are for future determination. (CMK)

  14. Minority Achievement Report.

    ERIC Educational Resources Information Center

    Prince George's Community Coll., Largo, MD. Office of Institutional Research and Analysis.

    This report summarizes the achievements of Prince George's Community College (PGCC) with regard to minority outcomes. Table 1 summarizes the undergraduate enrollment trends for African Americans as well as total minorities from fall 1994 through fall 1998. Both the headcount number of African American students and the proportion of African…

  15. Appraising Reading Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    To determine quality sequence in pupil progress, evaluation approaches need to be used which guide the teacher to assist learners to attain optimally. Teachers must use a variety of procedures to appraise student achievement in reading, because no one approach is adequate. Appraisal approaches might include: (1) observation and subsequent…

  16. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

    PubMed Central

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

    2016-01-01

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

  17. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information.

    PubMed

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

    2016-01-01

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

  18. Data accuracy assessment using enterprise architecture

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  19. On Achieving Experimental Accuracy from Molecular Dynamics Simulations of Flexible Molecules: Aqueous Glycerol

    PubMed Central

    Yongye, Austin B.; Foley, B. Lachele; Woods, Robert J.

    2014-01-01

    The rotational isomeric states (RIS) of glycerol at infinite dilution have been characterized in the aqueous phase via a 1 μs conventional molecular dynamics (MD) simulation, a 40 ns enhanced sampling replica exchange molecular dynamics (REMD) simulation, and a reevaluation of the experimental NMR data. The MD and REMD simulations employed the GLYCAM06/AMBER force field with explicit treatment of solvation. The shorter time scale of the REMD sampling method gave rise to RIS and theoretical scalar 3JHH coupling constants that were comparable to those from the much longer traditional MD simulation. The 3JHH coupling constants computed from the MD methods were in excellent agreement with those observed experimentally. Despite the agreement between the computed and the experimental J-values, there were variations between the rotamer populations computed directly from the MD data and those derived from the experimental NMR data. The experimentally derived populations were determined utilizing limiting J-values from an analysis of NMR data from substituted ethane molecules and may not be completely appropriate for application in more complex molecules, such as glycerol. Here, new limiting J-values have been derived via a combined MD and quantum mechanical approach and were used to decompose the experimental 3JHH coupling constants into population distributions for the glycerol RIS. PMID:18311953

  20. Use of model calibration to achieve high accuracy in analysis of computer networks

    DOEpatents

    Frogner, Bjorn; Guarro, Sergio; Scharf, Guy

    2004-05-11

    A system and method are provided for creating a network performance prediction model, and calibrating the prediction model, through application of network load statistical analyses. The method includes characterizing the measured load on the network, which may include background load data obtained over time, and may further include directed load data representative of a transaction-level event. Probabilistic representations of load data are derived to characterize the statistical persistence of the network performance variability and to determine delays throughout the network. The probabilistic representations are applied to the network performance prediction model to adapt the model for accurate prediction of network performance. Certain embodiments of the method and system may be used for analysis of the performance of a distributed application characterized as data packet streams.

  1. Achieving Higher Accuracy in the Gamma-Ray Spectrocopic Assay of Holdup

    SciTech Connect

    Russo, P.A.; Wenz, T.R.; Smith, S.E.; Harris, J.F.

    2000-09-01

    Gamma-ray spectroscopy is an important technique for the measurement of quantities of nuclear material holdup in processing equipment. Because the equipment in large facilities dedicated to uranium isotopic enrichment, uranium/plutonium scrap recovery or various stages of fuel fabrication is extensive, the total holdup may be large by its distribution alone, even if deposit thicknesses are small. Good accountability practices require unbiased measurements with uncertainties that are as small as possible. This paper describes new procedures for use with traditional holdup analysis methods based on gamma-ray spectroscopy. The procedures address the two sources of bias inherent in traditional gamma-ray measurements of holdup. Holdup measurements are performed with collimated, shielded gamma-ray detectors. The measurement distance is chosen to simplify the deposit geometry to that of a point, line or area. The quantitative holdup result is based on the net count rate of a representative gamma ray. This rate is corrected for contributions from room background and for attenuation by the process equipment. Traditional holdup measurements assume that the width of the point or line deposit is very small compared to the measurement distance, and that the self-attenuation effects can be neglected. Because each point or line deposit has a finite width and because self-attenuation affects all measurements, bias is incurred in both assumptions. In both cases the bias is negative, explaining the systematically low results of gamma-ray holdup measurements. The new procedures correct for bias that arises from both the finite-source effects and the gamma-ray self-attenuation. The procedures used to correct for both of these effects apply to the generalized geometries. One common empirical parameter is used for both corrections. It self-consistently limits the total error incurred (from uncertain knowledge of this parameter) in the combined correction process, so that it is compelling to use these procedures. The algorithms and the procedures are simple, general, and easily automated for use plant-wide. This paper shows the derivation of the new, generalized correction algorithms for finite-source and self-attenuation effects. It also presents an analysis of the sensitivity of the holdup result to the uncertainty in the empirical parameter when one or both corrections are made. The paper uses specific examples of the magnitudes of finite-source and self-attenuation corrections to measurements that were made in the field. It discusses the automated implementation of the correction procedure.

  2. Preschoolers Monitor the Relative Accuracy of Informants

    ERIC Educational Resources Information Center

    Pasquini, Elisabeth S.; Corriveau, Kathleen H.; Koenig, Melissa; Harris, Paul L.

    2007-01-01

    In 2 studies, the sensitivity of 3- and 4-year-olds to the previous accuracy of informants was assessed. Children viewed films in which 2 informants labeled familiar objects with differential accuracy (across the 2 experiments, children were exposed to the following rates of accuracy by the more and less accurate informants, respectively: 100% vs.…

  3. Large-Scale Chemical Similarity Networks for Target Profiling of Compounds Identified in Cell-Based Chemical Screens

    PubMed Central

    Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z.

    2015-01-01

    Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60–70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/). PMID:25826798

  4. Range accuracy analysis of streak tube imaging lidar systems

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  5. Accuracy potential of large-format still-video cameras

    NASA Astrophysics Data System (ADS)

    Maas, Hans-Gerd; Niederoest, Markus

    1997-07-01

    High resolution digital stillvideo cameras have found wide interest in digital close range photogrammetry in the last five years. They can be considered fully autonomous digital image acquisition systems without the requirement of permanent connection to an external power supply and a host computer for camera control and data storage, thus allowing for convenient data acquisition in many applications of digital photogrammetry. The accuracy potential of stillvideo cameras has been extensively discussed. While large format CCD sensors themselves can be considered very accurate measurement devices, lenses, camera bodies and sensor mounts of stillvideo cameras are not compression techniques in image storage, which may also affect the accuracy potential. This presentation shows recent experiences from accuracy tests with a number of large format stillvideo cameras, including a modified Kodak DCS200, a Kodak DCS460, a Nikon E2 and a Polaroid PDC-2000. The tests of the cameras include absolute and relative measurements and were performed using strong photogrammetric networks and good external reference. The results of the tests indicate that very high accuracies can be achieved with large blocks of stillvideo imagery especially in deformation measurements. In absolute measurements, however, the accuracy potential of the large format CCD sensors is partly ruined by a lack of stability of the cameras.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  7. Accuracy analysis and design of A3 parallel spindle head

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  8. Project ACHIEVE final report

    SciTech Connect

    1997-06-13

    Project ACHIEVE was a math/science academic enhancement program aimed at first year high school Hispanic American students. Four high schools -- two in El Paso, Texas and two in Bakersfield, California -- participated in this Department of Energy-funded program during the spring and summer of 1996. Over 50 students, many of whom felt they were facing a nightmare future, were given the opportunity to work closely with personal computers and software, sophisticated calculators, and computer-based laboratories -- an experience which their regular academic curriculum did not provide. Math and science projects, exercises, and experiments were completed that emphasized independent and creative applications of scientific and mathematical theories to real world problems. The most important outcome was the exposure Project ACHIEVE provided to students concerning the college and technical-field career possibilities available to them.

  9. Achieving Goal Blood Pressure.

    PubMed

    Laurent, Stéphane

    2015-07-01

    Both monotherapy and combination therapy options are appropriate for antihypertensive therapy according to the 2013 European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines. Most patients require more than one agent to achieve blood pressure (BP) control, and adding a second agent is more effective than doubling the dose of existing therapy. The addition of a third agent may be required to achieve adequate BP reductions in some patients. Single-pill fixed-dose combinations (FDCs) allow multiple-drug regimens to be delivered without any negative impact on patient compliance or persistence with therapy. FDCs also have documented beneficial clinical effects and use of FDCs containing two or three agents is recommended by the 2013 ESH/ESC guidelines. PMID:26002423

  10. Prediction of soil properties using imaging spectroscopy: Considering fractional vegetation cover to improve accuracy

    NASA Astrophysics Data System (ADS)

    Franceschini, M. H. D.; Demattê, J. A. M.; da Silva Terra, F.; Vicente, L. E.; Bartholomeus, H.; de Souza Filho, C. R.

    2015-06-01

    Spectroscopic techniques have become attractive to assess soil properties because they are fast, require little labor and may reduce the amount of laboratory waste produced when compared to conventional methods. Imaging spectroscopy (IS) can have further advantages compared to laboratory or field proximal spectroscopic approaches such as providing spatially continuous information with a high density. However, the accuracy of IS derived predictions decreases when the spectral mixture of soil with other targets occurs. This paper evaluates the use of spectral data obtained by an airborne hyperspectral sensor (ProSpecTIR-VS - Aisa dual sensor) for prediction of physical and chemical properties of Brazilian highly weathered soils (i.e., Oxisols). A methodology to assess the soil spectral mixture is adapted and a progressive spectral dataset selection procedure, based on bare soil fractional cover, is proposed and tested. Satisfactory performances are obtained specially for the quantification of clay, sand and CEC using airborne sensor data (R2 of 0.77, 0.79 and 0.54; RPD of 2.14, 2.22 and 1.50, respectively), after spectral data selection is performed; although results obtained for laboratory data are more accurate (R2 of 0.92, 0.85 and 0.75; RPD of 3.52, 2.62 and 2.04, for clay, sand and CEC, respectively). Most importantly, predictions based on airborne-derived spectra for which the bare soil fractional cover is not taken into account show considerable lower accuracy, for example for clay, sand and CEC (RPD of 1.52, 1.64 and 1.16, respectively). Therefore, hyperspectral remotely sensed data can be used to predict topsoil properties of highly weathered soils, although spectral mixture of bare soil with vegetation must be considered in order to achieve an improved prediction accuracy.

  11. Accuracy assessment of fluoroscopy-transesophageal echocardiography registration

    NASA Astrophysics Data System (ADS)

    Lang, Pencilla; Seslija, Petar; Bainbridge, Daniel; Guiraudon, Gerard M.; Jones, Doug L.; Chu, Michael W.; Holdsworth, David W.; Peters, Terry M.

    2011-03-01

    This study assesses the accuracy of a new transesophageal (TEE) ultrasound (US) fluoroscopy registration technique designed to guide percutaneous aortic valve replacement. In this minimally invasive procedure, a valve is inserted into the aortic annulus via a catheter. Navigation and positioning of the valve is guided primarily by intra-operative fluoroscopy. Poor anatomical visualization of the aortic root region can result in incorrect positioning, leading to heart valve embolization, obstruction of the coronary ostia and acute kidney injury. The use of TEE US images to augment intra-operative fluoroscopy provides significant improvements to image-guidance. Registration is achieved using an image-based TEE probe tracking technique and US calibration. TEE probe tracking is accomplished using a single-perspective pose estimation algorithm. Pose estimation from a single image allows registration to be achieved using only images collected in standard OR workflow. Accuracy of this registration technique is assessed using three models: a point target phantom, a cadaveric porcine heart with implanted fiducials, and in-vivo porcine images. Results demonstrate that registration can be achieved with an RMS error of less than 1.5mm, which is within the clinical accuracy requirements of 5mm. US-fluoroscopy registration based on single-perspective pose estimation demonstrates promise as a method for providing guidance to percutaneous aortic valve replacement procedures. Future work will focus on real-time implementation and a visualization system that can be used in the operating room.

  12. ACCURACY OF CO2 SENSORS

    SciTech Connect

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

    2008-10-01

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

  13. Astrophysics with Microarcsecond Accuracy Astrometry

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.

    2008-01-01

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

  14. High accuracy broadband infrared spectropolarimetry

    NASA Astrophysics Data System (ADS)

    Krishnaswamy, Venkataramanan

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

  15. Sensitivity and accuracy of whole effluent toxicity (WET) tests

    SciTech Connect

    Chapman, G.; Lussier, S.; Norberg-King, T.; Poucher, S.; Thursby, G.

    1995-12-31

    Direct measurement of effluent toxicity is a critical tool in controlling ambient toxicity. Lack of water quality criteria for many commonly discharged chemicals and complicated toxicological interactions in complex effluents are common. Complex effluent toxicity tests should provide limits as protective as National Criteria for single chemicals. One way to evaluate WET test sensitivity and accuracy is to compare WET test results with single chemicals to the National Criteria for these chemicals. A study of eight criteria chemicals (ammonia, analine, cadmium, carbaryl, copper, lead, methyl parathion, and zinc), two freshwater WET tests (Pimephales and Ceriodaphnia), and four marine WET tests (Arbacia, Champia, Menidia, and Mysidopsis) was conducted to provide this comparison. The most sensitive of the freshwater and marine WET tests with each chemical were generally less protective than the National Final Chronic Value (FCV) concentration by factors ranging from 1.09 to 44. Less-sensitive WET tests with each chemical represented significant underestimation of chronic toxicity by factors often in the range of 100--10,000. In two instances WET test results (copper and Champia, zinc and Ceriodaphnia) were below FCV by factors of 1.85 and 3.4, respectively. It is recognized that Champia is extremely sensitive to copper and that Daphnids may not be protected by the current National zinc criterion, thus these results are not surprising. Adequate accuracy for WET tests usually requires that the most sensitive WET-test species by utilized. Although the bias of WET tests to underestimate chronic toxicity is relatively small, it should be considered in the selection of test endpoints and application of WET data.

  16. Ground Truth Sampling and LANDSAT Accuracy Assessment

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  17. High accuracy wall thickness loss monitoring

    NASA Astrophysics Data System (ADS)

    Gajdacsi, Attila; Cegla, Frederic

    2014-02-01

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

  18. Time and position accuracy using codeless GPS

    NASA Technical Reports Server (NTRS)

    Dunn, C. E.; Jefferson, D. C.; Lichten, S. M.; Thomas, J. B.; Vigue, Y.; Young, L. E.

    1994-01-01

    The Global Positioning System has allowed scientists and engineers to make measurements having accuracy far beyond the original 15 meter goal of the system. Using global networks of P-Code capable receivers and extensive post-processing, geodesists have achieved baseline precision of a few parts per billion, and clock offsets have been measured at the nanosecond level over intercontinental distances. A cloud hangs over this picture, however. The Department of Defense plans to encrypt the P-Code (called Anti-Spoofing, or AS) in the fall of 1993. After this event, geodetic and time measurements will have to be made using codeless GPS receivers. However, there appears to be a silver lining to the cloud. In response to the anticipated encryption of the P-Code, the geodetic and GPS receiver community has developed some remarkably effective means of coping with AS without classified information. We will discuss various codeless techniques currently available and the data noise resulting from each. We will review some geodetic results obtained using only codeless data, and discuss the implications for time measurements. Finally, we will present the status of GPS research at JPL in relation to codeless clock measurements.

  19. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

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

  20. Accuracy of cloud liquid water path from ground-based microwave radiometry 2. Sensor accuracy and synergy

    NASA Astrophysics Data System (ADS)

    Crewell, Susanne; LöHnert, Ulrich

    2003-06-01

    The influence of microwave radiometer accuracy on retrieved cloud liquid water path (LWP) was investigated. Sensor accuracy was assumed to be the sum of the relative (i.e., Gaussian noise) and the absolute accuracies of brightness temperatures. When statistical algorithms are developed the assumed noise should be as close as possible to the real measurements in order to avoid artifacts in the retrieved LWP distribution. Typical offset errors of 1 K in brightness temperatures can produce mean LWP errors of more than 30 g m-2 for a two-channel radiometer retrieval, although positively correlated brightness temperature offsets in both channels reduce this error to 16 g m-2. Large improvements in LWP retrieval accuracy of about 50% can be achieved by adding a 90-GHz channel to the two-channel retrieval. The inclusion of additional measurements, like cloud base height from a lidar ceilometer and cloud base temperature from an infrared radiometer, is invaluable in detecting cloud free scenes allowing an indirect evaluation of LWP accuracy in clear sky cases. This method was used to evaluate LWP retrieval algorithms based on different gas absorption models. Using two months of measurements, the Liebe 93 model provided the best results when the 90-GHz channel was incorporated into the standard two-channel retrievals.

  1. Total solar irradiance record accuracy and recent improvements

    NASA Astrophysics Data System (ADS)

    Kopp, Greg

    /TIMs are intended to achieve levels of absolute accuracy that should reduce the TSI record's reliance on measurement continuity. I will discuss the climate-derived requirements for the levels of absolute accuracy and instrument stability needed for TSI measurements and describe current work that is underway to achieve these measurement requirements.

  2. High accuracy localization of long term evolution based on a new multiple carrier noise model.

    PubMed

    Lee, Wah Ching; Hung, Faan Hei; Tsang, Kim Fung; Wu, Chung Kit; Chi, Hao Ran; Chui, Kwok Tai; Lau, Wing Hong

    2014-01-01

    A high accuracy localization technique using Long Term Evolution (LTE) based on a new and accurate multiple carrier noise model has been developed. In the noise consideration, the LTE multiple carriers phase noise has been incorporated so that a new and accurate noise model is achieved. An experiment was performed to characterize the phase noise of carriers at 2 GHz. The developed noise model was incorporated into LTE localization analysis in a high traffic area in Hong Kong to evaluate the accuracy of localization. The evaluation and analysis reveals that the new localization method achieves an improvement of about 10% accuracy comparing to existing widely adopted schemes. PMID:25436658

  3. High Accuracy Localization of Long Term Evolution Based on a New Multiple Carrier Noise Model

    PubMed Central

    Lee, Wah Ching; Hung, Faan Hei; Tsang, Kim Fung; Wu, Chung Kit; Chi, Hao Ran; Chui, Kwok Tai; Lau, Wing Hong

    2014-01-01

    A high accuracy localization technique using Long Term Evolution (LTE) based on a new and accurate multiple carrier noise model has been developed. In the noise consideration, the LTE multiple carriers phase noise has been incorporated so that a new and accurate noise model is achieved. An experiment was performed to characterize the phase noise of carriers at 2 GHz. The developed noise model was incorporated into LTE localization analysis in a high traffic area in Hong Kong to evaluate the accuracy of localization. The evaluation and analysis reveals that the new localization method achieves an improvement of about 10% accuracy comparing to existing widely adopted schemes. PMID:25436658

  4. Effects of coating material on the fabrication accuracy of focused ion beam machining of insulators

    NASA Astrophysics Data System (ADS)

    Joe, Hang-Eun; Park, Jae-Hyeong; Kim, Seong Hyeon; Kim, Gyuho; Jun, Martin B. G.; Min, Byung-Kwon

    2015-09-01

    Focused ion beam (FIB) machining of insulators is a crucial process in the rapid prototyping of nanodevices for optical applications. A conductive material is generally coated on the insulator prior to FIB machining to achieve high fabrication accuracy. In this paper, we report on the effects on machining accuracy of four coating materials: Pt, Ni, Ag, and Co. The dimensional accuracy at channel sidewalls was improved by selecting a coating material that induces charge-carrier generation in a small range. The geometric and electrical characteristics of the FIB-machined surfaces were evaluated to elucidate the association between the fabrication accuracy and the range of charge-carrier distribution.

  5. Thermal-chemical Mantle Convection Models With Adaptive Mesh Refinement

    NASA Astrophysics Data System (ADS)

    Leng, W.; Zhong, S.

    2008-12-01

    In numerical modeling of mantle convection, resolution is often crucial for resolving small-scale features. New techniques, adaptive mesh refinement (AMR), allow local mesh refinement wherever high resolution is needed, while leaving other regions with relatively low resolution. Both computational efficiency for large- scale simulation and accuracy for small-scale features can thus be achieved with AMR. Based on the octree data structure [Tu et al. 2005], we implement the AMR techniques into the 2-D mantle convection models. For pure thermal convection models, benchmark tests show that our code can achieve high accuracy with relatively small number of elements both for isoviscous cases (i.e. 7492 AMR elements v.s. 65536 uniform elements) and for temperature-dependent viscosity cases (i.e. 14620 AMR elements v.s. 65536 uniform elements). We further implement tracer-method into the models for simulating thermal-chemical convection. By appropriately adding and removing tracers according to the refinement of the meshes, our code successfully reproduces the benchmark results in van Keken et al. [1997] with much fewer elements and tracers compared with uniform-mesh models (i.e. 7552 AMR elements v.s. 16384 uniform elements, and ~83000 tracers v.s. ~410000 tracers). The boundaries of the chemical piles in our AMR code can be easily refined to the scales of a few kilometers for the Earth's mantle and the tracers are concentrated near the chemical boundaries to precisely trace the evolvement of the boundaries. It is thus very suitable for our AMR code to study the thermal-chemical convection problems which need high resolution to resolve the evolvement of chemical boundaries, such as the entrainment problems [Sleep, 1988].

  6. Achieving Magnet status.

    PubMed

    Ellis, Beckie; Gates, Judy

    2005-01-01

    Magnet has become the gold standard for nursing excellence. It is the symbol of effective and safe patient care. It evaluates components that inspire safe care, including employee satisfaction and retention, professional education, and effective interdisciplinary collaboration. In an organization whose mission focuses on excellent patient care, Banner Thunderbird Medical Center found that pursuing Magnet status was clearly the next step. In this article, we will discuss committee selection, education, team building, planning, and the discovery process that define the Magnet journey. The road to obtaining Magnet status has permitted many opportunities to celebrate our achievements. PMID:16056158

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

    PubMed

    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 <0.001) to 63% when aided by the Checklist. 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

  8. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  9. Tracking accuracy assessment for concentrator photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Norton, Matthew S. H.; Anstey, Ben; Bentley, Roger W.; Georghiou, George E.

    2010-10-01

    The accuracy to which a concentrator photovoltaic (CPV) system can track the sun is an important parameter that influences a number of measurements that indicate the performance efficiency of the system. This paper presents work carried out into determining the tracking accuracy of a CPV system, and illustrates the steps involved in gaining an understanding of the tracking accuracy. A Trac-Stat SL1 accuracy monitor has been used in the determination of pointing accuracy and has been integrated into the outdoor CPV module test facility at the Photovoltaic Technology Laboratories in Nicosia, Cyprus. Results from this work are provided to demonstrate how important performance indicators may be presented, and how the reliability of results is improved through the deployment of such accuracy monitors. Finally, recommendations on the use of such sensors are provided as a means to improve the interpretation of real outdoor performance.

  10. Recognizing outstanding achievements

    NASA Astrophysics Data System (ADS)

    Speiss, Fred

    One function of any professional society is to provide an objective, informed means for recognizing outstanding achievements in its field. In AGU's Ocean Sciences section we have a variety of means for carrying out this duty. They include recognition of outstanding student presentations at our meetings, dedication of special sessions, nomination of individuals to be fellows of the Union, invitations to present Sverdrup lectures, and recommendations for Macelwane Medals, the Ocean Sciences Award, and the Ewing Medal.Since the decision to bestow these awards requires initiative and judgement by members of our section in addition to a deserving individual, it seems appropriate to review the selection process for each and to urge you to identify those deserving of recognition.

  11. Achieving closure at Fernald

    SciTech Connect

    Bradburne, John; Patton, Tisha C.

    2001-02-25

    When Fluor Fernald took over the management of the Fernald Environmental Management Project in 1992, the estimated closure date of the site was more than 25 years into the future. Fluor Fernald, in conjunction with DOE-Fernald, introduced the Accelerated Cleanup Plan, which was designed to substantially shorten that schedule and save taxpayers more than $3 billion. The management of Fluor Fernald believes there are three fundamental concerns that must be addressed by any contractor hoping to achieve closure of a site within the DOE complex. They are relationship management, resource management and contract management. Relationship management refers to the interaction between the site and local residents, regulators, union leadership, the workforce at large, the media, and any other interested stakeholder groups. Resource management is of course related to the effective administration of the site knowledge base and the skills of the workforce, the attraction and retention of qualified a nd competent technical personnel, and the best recognition and use of appropriate new technologies. Perhaps most importantly, resource management must also include a plan for survival in a flat-funding environment. Lastly, creative and disciplined contract management will be essential to effecting the closure of any DOE site. Fluor Fernald, together with DOE-Fernald, is breaking new ground in the closure arena, and ''business as usual'' has become a thing of the past. How Fluor Fernald has managed its work at the site over the last eight years, and how it will manage the new site closure contract in the future, will be an integral part of achieving successful closure at Fernald.

  12. "Battleship Numberline": A Digital Game for Improving Estimation Accuracy on Fraction Number Lines

    ERIC Educational Resources Information Center

    Lomas, Derek; Ching, Dixie; Stampfer, Eliane; Sandoval, Melanie; Koedinger, Ken

    2011-01-01

    Given the strong relationship between number line estimation accuracy and math achievement, might a computer-based number line game help improve math achievement? In one study by Rittle-Johnson, Siegler and Alibali (2001), a simple digital game called "Catch the Monster" provided practice in estimating the location of decimals on a number line.…

  13. Achievement Goals and Achievement Emotions: A Meta-Analysis

    ERIC Educational Resources Information Center

    Huang, Chiungjung

    2011-01-01

    This meta-analysis synthesized 93 independent samples (N = 30,003) in 77 studies that reported in 78 articles examining correlations between achievement goals and achievement emotions. Achievement goals were meaningfully associated with different achievement emotions. The correlations of mastery and mastery approach goals with positive achievement…

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

    PubMed

    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. PMID:26513777

  15. Differential signal scatterometry overlay metrology: an accuracy investigation

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel; Adel, Mike; Dinu, Berta; Golovanevsky, Boris; Izikson, Pavel; Levinski, Vladimir; Vakshtein, Irina; Leray, Philippe; Vasconi, Mauro; Salski, Bartlomiej

    2007-06-01

    The overlay control budget for the 32nm technology node will be 5.7nm according to the ITRS. The overlay metrology budget is typically 1/10 of the overlay control budget resulting in overlay metrology total measurement uncertainty (TMU) requirements of 0.57nm for the most challenging use cases of the 32nm node. The current state of the art imaging overlay metrology technology does not meet this strict requirement, and further technology development is required to bring it to this level. In this work we present results of a study of an alternative technology for overlay metrology - Differential signal scatterometry overlay (SCOL). Theoretical considerations show that overlay technology based on differential signal scatterometry has inherent advantages, which will allow it to achieve the 32nm technology node requirements and go beyond it. We present results of simulations of the expected accuracy associated with a variety of scatterometry overlay target designs. We also present our first experimental results of scatterometry overlay measurements, comparing this technology with the standard imaging overlay metrology technology. In particular, we present performance results (precision and tool induced shift) and address the issue of accuracy of scatterometry overlay. We show that with the appropriate target design and algorithms scatterometry overlay achieves the accuracy required for future technology nodes.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  17. Objective sampling with EAGLE to improve acoustic prediction accuracy

    NASA Astrophysics Data System (ADS)

    Rike, Erik R.; Delbalzo, Donald R.

    2003-10-01

    Some Navy operations require extensive acoustic calculations. The standard computational approach is to calculate on a regular grid of points and radials. In complex environmental areas, this implies a dense grid and many radials (i.e., long run times) to achieve acceptable accuracy and detail. However, Navy tactical decision aid calculations must be timely and exhibit adequate accuracy or the results may be too old or too imprecise to be valuable. This dilemma led to a new concept, OGRES (Objective Grid/Radials using Environmentally-sensitive Selection), which produces irregular acoustic grids [Rike and DelBalzo, Proc. IEEE Oceans (2002)]. Its premise is that physical environmental complexity controls the need for dense sampling in space and azimuth, and that transmission loss already computed for nearby coordinates on previous iterations can be used to predict that complexity. Recent work in this area to further increase accuracy and efficiency by using better metrics and interpolation routines has led to the Efficient Acoustic Gridder for Littoral Environments (EAGLE). On each iteration, EAGLE produces an acoustic field for the entire area of interest with ever-increasing resolution and accuracy. An example is presented where approximately an order of magnitude efficiency improvement (over regular grids) is demonstrated. [Work sponsored by ONR.

  18. Machine learning predictions of molecular properties: Accurate many-body potentials and nonlocality in chemical space

    DOE PAGESBeta

    Hansen, Katja; Biegler, Franziska; Ramakrishnan, Raghunathan; Pronobis, Wiktor; von Lilienfeld, O. Anatole; Müller, Klaus -Robert; Tkatchenko, Alexandre

    2015-06-04

    Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical industries. Aiming toward this goal, we develop and apply a systematic hierarchy of efficient empirical methods to estimate atomization and total energies of molecules. These methods range from a simple sum over atoms, to addition of bond energies, to pairwise interatomic force fields, reaching to the more sophisticated machine learning approaches that are capable of describing collective interactions between many atoms or bonds. In the case of equilibrium molecular geometries, even simple pairwise force fields demonstratemore » prediction accuracy comparable to benchmark energies calculated using density functional theory with hybrid exchange-correlation functionals; however, accounting for the collective many-body interactions proves to be essential for approaching the “holy grail” of chemical accuracy of 1 kcal/mol for both equilibrium and out-of-equilibrium geometries. This remarkable accuracy is achieved by a vectorized representation of molecules (so-called Bag of Bonds model) that exhibits strong nonlocality in chemical space. The same representation allows us to predict accurate electronic properties of molecules, such as their polarizability and molecular frontier orbital energies.« less

  19. Machine learning predictions of molecular properties: Accurate many-body potentials and nonlocality in chemical space

    SciTech Connect

    Hansen, Katja; Biegler, Franziska; Ramakrishnan, Raghunathan; Pronobis, Wiktor; von Lilienfeld, O. Anatole; Müller, Klaus -Robert; Tkatchenko, Alexandre

    2015-06-04

    Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical industries. Aiming toward this goal, we develop and apply a systematic hierarchy of efficient empirical methods to estimate atomization and total energies of molecules. These methods range from a simple sum over atoms, to addition of bond energies, to pairwise interatomic force fields, reaching to the more sophisticated machine learning approaches that are capable of describing collective interactions between many atoms or bonds. In the case of equilibrium molecular geometries, even simple pairwise force fields demonstrate prediction accuracy comparable to benchmark energies calculated using density functional theory with hybrid exchange-correlation functionals; however, accounting for the collective many-body interactions proves to be essential for approaching the “holy grail” of chemical accuracy of 1 kcal/mol for both equilibrium and out-of-equilibrium geometries. This remarkable accuracy is achieved by a vectorized representation of molecules (so-called Bag of Bonds model) that exhibits strong nonlocality in chemical space. The same representation allows us to predict accurate electronic properties of molecules, such as their polarizability and molecular frontier orbital energies.

  20. Entrepreneur achievement. Liaoning province.

    PubMed

    Zhao, R

    1994-03-01

    This paper reports the successful entrepreneurial endeavors of members of a 20-person women's group in Liaoning Province, China. Jing Yuhong, a member of the Family Planning Association at Shileizi Village, Dalian City, provided the basis for their achievements by first building an entertainment/study room in her home to encourage married women to learn family planning. Once stocked with books, magazines, pamphlets, and other materials on family planning and agricultural technology, dozens of married women in the neighborhood flocked voluntarily to the room. Yuhong also set out to give these women a way to earn their own income as a means of helping then gain greater equality with their husbands and exert greater control over their personal reproductive and social lives. She gave a section of her farming land to the women's group, loaned approximately US$5200 to group members to help them generate income from small business initiatives, built a livestock shed in her garden for the group to raise marmots, and erected an awning behind her house under which mushrooms could be grown. The investment yielded $12,000 in the first year, allowing each woman to keep more than $520 in dividends. Members then soon began going to fairs in the capital and other places to learn about the outside world, and have successfully ventured out on their own to generate individual incomes. Ten out of twenty women engaged in these income-generating activities asked for and got the one-child certificate. PMID:12287775

  1. Chemical strategies for die/wafer submicron alignment and bonding.

    SciTech Connect

    Martin, James Ellis; Baca, Alicia I.; Chu, Dahwey; Rohwer, Lauren Elizabeth Shea

    2010-09-01

    This late-start LDRD explores chemical strategies that will enable sub-micron alignment accuracy of dies and wafers by exploiting the interfacial energies of chemical ligands. We have micropatterned commensurate features, such as 2-d arrays of micron-sized gold lines on the die to be bonded. Each gold line is functionalized with alkanethiol ligands before the die are brought into contact. The ligand interfacial energy is minimized when the lines on the die are brought into registration, due to favorable interactions between the complementary ligand tails. After registration is achieved, standard bonding techniques are used to create precision permanent bonds. We have computed the alignment forces and torque between two surfaces patterned with arrays of lines or square pads to illustrate how best to maximize the tendency to align. We also discuss complex, aperiodic patterns such as rectilinear pad assemblies, concentric circles, and spirals that point the way towards extremely precise alignment.

  2. The Homogeneity of School Achievement.

    ERIC Educational Resources Information Center

    Cahan, Sorel

    Since the measurement of school achievement involves the administration of achievement tests to various grades on various subjects, both grade level and subject matter contribute to within-school achievement variations. To determine whether achievement test scores vary most among different fields within a grade level, or within fields among…

  3. Accuracy analysis of distributed simulation systems

    NASA Astrophysics Data System (ADS)

    Lin, Qi; Guo, Jing

    2010-08-01

    Existed simulation works always emphasize on procedural verification, which put too much focus on the simulation models instead of simulation itself. As a result, researches on improving simulation accuracy are always limited in individual aspects. As accuracy is the key in simulation credibility assessment and fidelity study, it is important to give an all-round discussion of the accuracy of distributed simulation systems themselves. First, the major elements of distributed simulation systems are summarized, which can be used as the specific basis of definition, classification and description of accuracy of distributed simulation systems. In Part 2, the framework of accuracy of distributed simulation systems is presented in a comprehensive way, which makes it more sensible to analyze and assess the uncertainty of distributed simulation systems. The concept of accuracy of distributed simulation systems is divided into 4 other factors and analyzed respectively further more in Part 3. In Part 4, based on the formalized description of framework of accuracy analysis in distributed simulation systems, the practical approach are put forward, which can be applied to study unexpected or inaccurate simulation results. Following this, a real distributed simulation system based on HLA is taken as an example to verify the usefulness of the approach proposed. The results show that the method works well and is applicable in accuracy analysis of distributed simulation systems.

  4. Accuracy of Parent Identification of Stuttering Occurrence

    ERIC Educational Resources Information Center

    Einarsdottir, Johanna; Ingham, Roger

    2009-01-01

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

  5. Stereotype Accuracy: Toward Appreciating Group Differences.

    ERIC Educational Resources Information Center

    Lee, Yueh-Ting, Ed.; And Others

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

  6. Accuracy assessment of GPS satellite orbits

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  7. The Accuracy of Gender Stereotypes Regarding Occupations.

    ERIC Educational Resources Information Center

    Beyer, Sylvia; Finnegan, Andrea

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

  8. Individual Differences in Eyewitness Recall Accuracy.

    ERIC Educational Resources Information Center

    Berger, James D.; Herringer, Lawrence G.

    1991-01-01

    Presents study results comparing college students' self-evaluation of recall accuracy to actual recall of detail after viewing a crime scenario. Reports that self-reported ability to remember detail correlates with accuracy in memory of specifics. Concludes that people may have a good indication early in the eyewitness situation of whether they…

  9. Scientific Sources' Perception of Network News Accuracy.

    ERIC Educational Resources Information Center

    Moore, Barbara; Singletary, Michael

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

  10. Accuracy of Carbohydrate Counting in Adults.

    PubMed

    Meade, Lisa T; Rushton, Wanda E

    2016-07-01

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

  11. HEPEX - achievements and challenges!

    NASA Astrophysics Data System (ADS)

    Pappenberger, Florian; Ramos, Maria-Helena; Thielen, Jutta; Wood, Andy; Wang, Qj; Duan, Qingyun; Collischonn, Walter; Verkade, Jan; Voisin, Nathalie; Wetterhall, Fredrik; Vuillaume, Jean-Francois Emmanuel; Lucatero Villasenor, Diana; Cloke, Hannah L.; Schaake, John; van Andel, Schalk-Jan

    2014-05-01

    HEPEX is an international initiative bringing together hydrologists, meteorologists, researchers and end-users to develop advanced probabilistic hydrological forecast techniques for improved flood, drought and water management. HEPEX was launched in 2004 as an independent, cooperative international scientific activity. During the first meeting, the overarching goal was defined as: "to develop and test procedures to produce reliable hydrological ensemble forecasts, and to demonstrate their utility in decision making related to the water, environmental and emergency management sectors." The applications of hydrological ensemble predictions span across large spatio-temporal scales, ranging from short-term and localized predictions to global climate change and regional modeling. Within the HEPEX community, information is shared through its blog (www.hepex.org), meetings, testbeds and intercompaison experiments, as well as project reportings. Key questions of HEPEX are: * What adaptations are required for meteorological ensemble systems to be coupled with hydrological ensemble systems? * How should the existing hydrological ensemble prediction systems be modified to account for all sources of uncertainty within a forecast? * What is the best way for the user community to take advantage of ensemble forecasts and to make better decisions based on them? This year HEPEX celebrates its 10th year anniversary and this poster will present a review of the main operational and research achievements and challenges prepared by Hepex contributors on data assimilation, post-processing of hydrologic predictions, forecast verification, communication and use of probabilistic forecasts in decision-making. Additionally, we will present the most recent activities implemented by Hepex and illustrate how everyone can join the community and participate to the development of new approaches in hydrologic ensemble prediction.

  12. Optimizing the geometrical accuracy of curvilinear meshes

    NASA Astrophysics Data System (ADS)

    Toulorge, Thomas; Lambrechts, Jonathan; Remacle, Jean-François

    2016-04-01

    This paper presents a method to generate valid high order meshes with optimized geometrical accuracy. The high order meshing procedure starts with a linear mesh, that is subsequently curved without taking care of the validity of the high order elements. An optimization procedure is then used to both untangle invalid elements and optimize the geometrical accuracy of the mesh. Standard measures of the distance between curves are considered to evaluate the geometrical accuracy in planar two-dimensional meshes, but they prove computationally too costly for optimization purposes. A fast estimate of the geometrical accuracy, based on Taylor expansions of the curves, is introduced. An unconstrained optimization procedure based on this estimate is shown to yield significant improvements in the geometrical accuracy of high order meshes, as measured by the standard Hausdorff distance between the geometrical model and the mesh. Several examples illustrate the beneficial impact of this method on CFD solutions, with a particular role of the enhanced mesh boundary smoothness.

  13. High accuracy ground target location using loitering munitions platforms

    NASA Astrophysics Data System (ADS)

    Wang, Zhifei; Wang, Hua; Han, Jing

    2011-08-01

    Precise ground target localization is an interesting problem and relevant not only for military but also for civilian applications, and this is expected to be an emerging field with many potential applications. Ground Target Location Using Loitering Munitions (LM) requires estimation of aircraft position and attitude to a high degree of accuracy, and data derived by processing sensor images might be useful for supplementing other navigation sensor information and increasing the reliability and accuracy of navigation estimates during this flight phase. This paper presents a method for high accuracy ground target localization using Loitering Munitions (LM) equipped with a video camera sensor. The proposed method is based on a satellite or aerial image matching technique. In order to acquire the target position of ground intelligently and rapidly and to improve the localization accuracy estimating the target position jointly with the systematic LM and camera attitude measurement errors, several techniques have been proposed. Firstly, ground target geo-location based on tray tracing was used for comparison against our approach. By proposed methods the calculation from pixel to world coordinates can be done. Then Hough transform was used to image alignment and a median filter was applied for removing small details which are visible from the sensed image but not visible from the reference image. Finally, A novel edge detection method and an image matching algorithm based on bifurcation extraction were proposed. This method did not require accurate knowledge of the aircraft position and attitude and high performance sensors, therefore it is especially suitable for LM which did not have capability to carry accurate sensors due to their limited play weight and power resources. The results of simulation experiments and theory analyzing demonstrate that high accuracy ground target localization is reached with low performance sensors, and achieve timely. The method is used in

  14. The Role of Feedback on Studying, Achievement and Calibration.

    ERIC Educational Resources Information Center

    Chu, Stephanie T. L.; Jamieson-Noel, Dianne L.; Winne, Philip H.

    One set of hypotheses examined in this study was that various types of feedback (outcome, process, and corrective) supply different information about performance and have different effects on studying processes and on achievement. Another set of hypotheses concerned students' calibration, their accuracy in predicting and postdicting achievement…

  15. Anatomy-aware measurement of segmentation accuracy

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  16. The Social Accuracy Model of Interpersonal Perception: Assessing Individual Differences in Perceptive and Expressive Accuracy

    ERIC Educational Resources Information Center

    Biesanz, Jeremy C.

    2010-01-01

    The social accuracy model of interpersonal perception (SAM) is a componential model that estimates perceiver and target effects of different components of accuracy across traits simultaneously. For instance, Jane may be generally accurate in her perceptions of others and thus high in "perceptive accuracy"--the extent to which a particular…

  17. Systematic review of discharge coding accuracy

    PubMed Central

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

    2012-01-01

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

  18. The NASA High Accuracy Fuel Flowmeter (HAFF) Development Program

    NASA Technical Reports Server (NTRS)

    Hobart, H. F.

    1983-01-01

    The high accuracy fuel flowmeter development program is described. A flightworthy meter that measures mass flowrate of aircraft fuels to within + or - 0.25% of reading over a 50:1 range of flow is developed. A study of measurement techniques to achieve this goal yielded three candidates: (1) a dual turbine flowmeter with density and viscosity compensation; (2) an angular momentum flowmeter with a motor-driven, spring-restrained turbine and viscosity shroud; and (3) a vortex precission flowmeter with density and viscosity compensation. An experimental study of each technique was completed and the first two candidates were selected for prototype development.

  19. The Impact of Reading Achievement on Overall Academic Achievement

    ERIC Educational Resources Information Center

    Churchwell, Dawn Earheart

    2009-01-01

    This study examined the relationship between reading achievement and achievement in other subject areas. The purpose of this study was to determine if there was a correlation between reading scores as measured by the Standardized Test for the Assessment of Reading (STAR) and academic achievement in language arts, math, science, and social studies…

  20. Attitude Towards Physics and Additional Mathematics Achievement Towards Physics Achievement

    ERIC Educational Resources Information Center

    Veloo, Arsaythamby; Nor, Rahimah; Khalid, Rozalina

    2015-01-01

    The purpose of this research is to identify the difference in students' attitude towards Physics and Additional Mathematics achievement based on gender and relationship between attitudinal variables towards Physics and Additional Mathematics achievement with achievement in Physics. This research focused on six variables, which is attitude towards…

  1. Predicting Mathematics Achievement: The Influence of Prior Achievement and Attitudes

    ERIC Educational Resources Information Center

    Hemmings, Brian; Grootenboer, Peter; Kay, Russell

    2011-01-01

    Achievement in mathematics is inextricably linked to future career opportunities, and therefore, understanding those factors that influence achievement is important. This study sought to examine the relationships among attitude towards mathematics, ability and mathematical achievement. This examination was also supported by a focus on gender…

  2. Geometric accuracy in airborne SAR images

    NASA Technical Reports Server (NTRS)

    Blacknell, D.; Quegan, S.; Ward, I. A.; Freeman, A.; Finley, I. P.

    1989-01-01

    Uncorrected across-track motions of a synthetic aperture radar (SAR) platform can cause both a severe loss of azimuthal positioning accuracy in, and defocusing of, the resultant SAR image. It is shown how the results of an autofocus procedure can be incorporated in the azimuth processing to produce a fully focused image that is geometrically accurate in azimuth. Range positioning accuracy is also discussed, leading to a comprehensive treatment of all aspects of geometric accuracy. The system considered is an X-band SAR.

  3. High accuracy calibration of the fiber spectroradiometer

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  4. Discrimination in measures of knowledge monitoring accuracy

    PubMed Central

    Was, Christopher A.

    2014-01-01

    Knowledge monitoring predicts academic outcomes in many contexts. However, measures of knowledge monitoring accuracy are often incomplete. In the current study, a measure of students’ ability to discriminate known from unknown information as a component of knowledge monitoring was considered. Undergraduate students’ knowledge monitoring accuracy was assessed and used to predict final exam scores in a specific course. It was found that gamma, a measure commonly used as the measure of knowledge monitoring accuracy, accounted for a small, but significant amount of variance in academic performance whereas the discrimination and bias indexes combined to account for a greater amount of variance in academic performance. PMID:25339979

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

    PubMed Central

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

    2014-01-01

    MEMS Inertial Measurement Units are available at low cost and can replace expensive units in mobile mapping platforms which need direct georeferencing. This is done through the integration with GNSS measurements in order to achieve a continuous positioning solution and to obtain orientation angles. This paper presents the results of the assessment of the accuracy of a system that integrates GNSS and a MEMS IMU in a terrestrial platform. We describe the methodology used and the tests realized where the accuracy of the positions and orientation parameters were assessed using an independent photogrammetric technique employing cameras that integrate the mobile mapping system developed by the authors. Results for the accuracy of attitude angles and coordinates show that accuracies better than a decimeter in positions, and under a degree in angles, can be achieved even considering that the terrestrial platform is operating in less than favorable environments. PMID:25375757

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Accuracy of quantitative visual soil assessment

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  8. Vibrationally averaged post Born-Oppenheimer isotopic dipole moment calculations approaching spectroscopic accuracy

    NASA Astrophysics Data System (ADS)

    Arapiraca, A. F. C.; Jonsson, Dan; Mohallem, J. R.

    2011-12-01

    We report an upgrade of the Dalton code to include post Born-Oppenheimer nuclear mass corrections in the calculations of (ro-)vibrational averages of molecular properties. These corrections are necessary to achieve an accuracy of 10-4 debye in the calculations of isotopic dipole moments. Calculations on the self-consistent field level present this accuracy, while numerical instabilities compromise correlated calculations. Applications to HD, ethane, and ethylene isotopologues are implemented, all of them approaching the experimental values.

  9. Vibrationally averaged post Born-Oppenheimer isotopic dipole moment calculations approaching spectroscopic accuracy.

    PubMed

    Arapiraca, A F C; Jonsson, Dan; Mohallem, J R

    2011-12-28

    We report an upgrade of the Dalton code to include post Born-Oppenheimer nuclear mass corrections in the calculations of (ro-)vibrational averages of molecular properties. These corrections are necessary to achieve an accuracy of 10(-4) debye in the calculations of isotopic dipole moments. Calculations on the self-consistent field level present this accuracy, while numerical instabilities compromise correlated calculations. Applications to HD, ethane, and ethylene isotopologues are implemented, all of them approaching the experimental values. PMID:22225162

  10. Improved single-strand DNA sizing accuracy in capillary electrophoresis.

    PubMed Central

    Rosenblum, B B; Oaks, F; Menchen, S; Johnson, B

    1997-01-01

    Interpolation algorithms can be developed to size unknown single-stranded (ss) DNA fragments based on their electrophoretic mobilities, when they are compared with the mobilities of standard fragments of known sizes; however, sequence-specific anomalous electrophoretic migration can affect the accuracy and precision of the called sizes of the fragments. We used the anomalous migration of ssDNA fragments to optimize denaturation conditions for capillary electrophoresis. The capillary electrophoretic system uses a refillable polymer that both coats the capillary wall to suppress electro-osmotic flow and acts as the sieving matrix. The addition of 8 M urea to the polymer solution, as in slab gel electrophoresis, is insufficient to fully denature some anomalously migrating ssDNA fragments in this capillary electrophoresis system. The sizing accuracy of these fragments is significantly improved by the addition of 2-pyrrolidinone, or increased capillary temperature (60 degrees C). the effect of these two denaturing strategies is additive, and the best accuracy and precision in sizing results are obtained with a combination of chemical and thermal denaturation. PMID:9380518

  11. Empathic Embarrassment Accuracy in Autism Spectrum Disorder.

    PubMed

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

    2015-06-01

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

  12. Coding accuracy on the psychophysical scale

    PubMed Central

    Kostal, Lubomir; Lansky, Petr

    2016-01-01

    Sensory neurons are often reported to adjust their coding accuracy to the stimulus statistics. The observed match is not always perfect and the maximal accuracy does not align with the most frequent stimuli. As an alternative to a physiological explanation we show that the match critically depends on the chosen stimulus measurement scale. More generally, we argue that if we measure the stimulus intensity on the scale which is proportional to the perception intensity, an improved adjustment in the coding accuracy is revealed. The unique feature of stimulus units based on the psychophysical scale is that the coding accuracy can be meaningfully compared for different stimuli intensities, unlike in the standard case of a metric scale. PMID:27021783

  13. Measuring the Accuracy of Diagnostic Systems.

    ERIC Educational Resources Information Center

    Swets, John A.

    1988-01-01

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

  14. Sun-pointing programs and their accuracy

    SciTech Connect

    Zimmerman, J.C.

    1981-05-01

    Several sun-pointing programs and their accuracy are described. FORTRAN program listings are given. Program descriptions are given for both Hewlett-Packard (HP-67) and Texas Instruments (TI-59) hand-held calculators.

  15. Nonverbal self-accuracy in interpersonal interaction.

    PubMed

    Hall, Judith A; Murphy, Nora A; Mast, Marianne Schmid

    2007-12-01

    Four studies measure participants' accuracy in remembering, without forewarning, their own nonverbal behavior after an interpersonal interaction. Self-accuracy for smiling, nodding, gazing, hand gesturing, and self-touching is scored by comparing the participants' recollections with coding based on videotape. Self-accuracy is above chance and of modest magnitude on average. Self-accuracy is greatest for smiling; intermediate for nodding, gazing, and gesturing; and lowest for self-touching. It is higher when participants focus attention away from the self (learning as much as possible about the partner, rearranging the furniture in the room, evaluating the partner, smiling and gazing at the partner) than when participants are more self-focused (getting acquainted, trying to make a good impression on the partner, being evaluated by the partner, engaging in more self-touching). The contributions of cognitive demand and affective state are discussed. PMID:18000102

  16. Biomass - chemicals

    SciTech Connect

    Kovaly, K.A.

    1982-08-01

    A host of industrial chemicals, specialty items, solvents, plastics, elastomers, fibers and films can be produced from agricultural crops, wood, paper mill wastes, food processing wastes, municipal waste and sewage. Existing chemical processes based on readily renewable plant materials are reviewed. These include ethanol and acetone-butanol fermentations, oilseed chemicals, furfural and cellulosics. (Refs. 16).

  17. Chemical sensor

    NASA Technical Reports Server (NTRS)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  18. Fitting magnetic field gradient with Heisenberg-scaling accuracy

    PubMed Central

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

    2014-01-01

    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. PMID:25487218

  19. [Research Reports on Academic Achievement.

    ERIC Educational Resources Information Center

    Latts, Sander; And Others

    1969-01-01

    Four counselors studied the relation between achievement and choice of major, achievement and motivation, counseling and motivation, and achievement and employment. To see if those with definite majors or career choices in mind did better than those without, 300 students were tested according to the certainty of their choice. No significant…

  20. Cherokee Culture and School Achievement.

    ERIC Educational Resources Information Center

    Brown, Anthony D.

    1980-01-01

    Compares the effect of cooperative and competitive behaviors of Cherokee and Anglo American elementary school students on academic achievement. Suggests changes in teaching techniques and lesson organization that might raise academic achievement while taking into consideration tribal traditions that limit scholastic achievement in an…

  1. How a GNSS Receiver Is Held May Affect Static Horizontal Position Accuracy

    PubMed Central

    Weaver, Steven A.; Ucar, Zennure; Bettinger, Pete; Merry, Krista

    2015-01-01

    understanding of antenna positioning within the receiver to achieve the greatest accuracy during data collection. PMID:25923667

  2. Accuracy comparison among different machine learning techniques for detecting malicious codes

    NASA Astrophysics Data System (ADS)

    Narang, Komal

    2016-03-01

    In this paper, a machine learning based model for malware detection is proposed. It can detect newly released malware i.e. zero day attack by analyzing operation codes on Android operating system. The accuracy of Naïve Bayes, Support Vector Machine (SVM) and Neural Network for detecting malicious code has been compared for the proposed model. In the experiment 400 benign files, 100 system files and 500 malicious files have been used to construct the model. The model yields the best accuracy 88.9% when neural network is used as classifier and achieved 95% and 82.8% accuracy for sensitivity and specificity respectively.

  3. Students' Conceptions of Chemical Change.

    ERIC Educational Resources Information Center

    Hesse, Joseph J., III; Anderson, Charles W.

    1992-01-01

    Presents results of intensive clinical interviews with 11 high school chemistry students representing a broad range of achievement levels as selected from 180 students who completed a written test upon completion of an instructional unit on chemical change. Results indicate that students commonly experience difficulties in chemical knowledge,…

  4. Kodak DCS200: a camera for high-accuracy measurements?

    NASA Astrophysics Data System (ADS)

    Gruen, Armin; Maas, Hans-Gerd; Keller, Andrea

    1995-09-01

    The digital high-resolution stillvideo camera Kodak DCS200 has reached a high degree of popularity among photogrammetrists within a very short time. Consisting of a mirror reflex camera, a high resolution CCD sensor, A/D conversion, power supply, and data storage capacity for 50 images, it can basically be considered a comfortable, autonomous device for digital image data acquisition, especially for industrial applications and for architectural photogrammetry. First tests of the camera showed a high precision potential: 1/20-1/30 pixel in image space could be achieved in several applications, and with large self-calibrating networks relative precisions of 1:100,000 and better have been reported. To be able to make more detailed statements on the accuracy potential of the camera, a thorough accuracy test was performed at ETH Zurich by taking 150 images of a 186 target 3D testfield. Although the precision estimates of this large block were exceptionally good, strong systematic object deformations were found in comparison with theodolite-measured reference coordinates of the testfield points. The reasons for these deformations are most probably temporal instabilities of some camera parameters, which could make the use of this camera very problematic for high accuracy applications. It is argued that these instabilities are caused by the weak fixture of the CCD-chip to the camera body. In this context it is often overlooked that this camera was not developed for precise measurement applications but rather for professional photographers.

  5. Operating a real time high accuracy positioning system

    NASA Astrophysics Data System (ADS)

    Johnston, G.; Hanley, J.; Russell, D.; Vooght, A.

    2003-04-01

    The paper shall review the history and development of real time DGPS services prior to then describing the design of a high accuracy GPS commercial augmentation system and service currently delivering over a wide area to users of precise positioning products. The infrastructure and system shall be explained in relation to the need for high accuracy and high integrity of positioning for users. A comparison of the different techniques for the delivery of data shall be provided to outline the technical approach taken. Examples of the performance of the real time system shall be shown in various regions and modes to outline the current achievable accuracies. Having described and established the current GPS based situation, a review of the potential of the Galileo system shall be presented. Following brief contextual information relating to the Galileo project, core system and services, the paper will identify possible key applications and the main user communities for sub decimetre level precise positioning. The paper will address the Galileo and modernised GPS signals in space that are relevant to commercial precise positioning for the future and will discuss the implications for precise positioning performance. An outline of the proposed architecture shall be described and associated with pointers towards a successful implementation. Central to this discussion will be an assessment of the likely evolution of system infrastructure and user equipment implementation, prospects for new applications and their effect upon the business case for precise positioning services.

  6. Prediction of OCR accuracy using simple image features

    SciTech Connect

    Blando, L.R.; Kanai, Junichi; Nartker, T.A.

    1995-04-01

    A classifier for predicting the character accuracy of a given page achieved by any Optical Character Recognition (OCR) system is presented. This classifier is based on measuring the amount of white speckle, the amount of character fragments, and overall size information in the page. No output from the OCR system is used. The given page is classified as either good quality (i.e., high OCR accuracy expected) or poor (i.e., low OCR accuracy expected). Six OCR systems processed two different sets of test data: a set of 439 pages obtained from technical and scientific documents and a set of 200 pages obtained from magazines. For every system, approximately 85% of the pages in each data set were correctly predicted. The performance of this classifier is also compared with the ideal-case performance of a prediction method based upon the number of reject markers in OCR generated text. In several cases, this method matched or exceeded the performance of the reject based approach.

  7. High-accuracy particle sizing by interferometric particle imaging

    NASA Astrophysics Data System (ADS)

    Qieni, Lü; Wenhua, Jin; Tong, Lü; Xiang, Wang; Yimo, Zhang

    2014-02-01

    A method of high-accuracy estimation of fringes number/fringes frequency of interferogram based on erosion match and the Fourier transform technique is proposed. The edge images of the interference pattern of particles and the particle mask image are detected respectively by erosion operating firstly and then subtracted with the respective original image, and the center coordinate of particles can be extracted through the 2D correlation operation for the two edge images obtained. The interference pattern of each particle can then be achieved using the center coordinate, the shape and size of the particle image. The number of fringes/fringe spacing of the interferogram of the particle is extracted by Fourier transform and the modified Rife algorithm, and sub-pixel accuracy of the extracted frequency is acquired. Its performance is demonstrated by numerical simulation and experimental measurement. The measurement uncertainty is ±0.91 μm and the relative error 1.13% for the standard particle of diameter 45 μm. The research results show that the algorithm presented boasts high accuracy for particle sizing as well as location measurement.

  8. Students' Achievement Goals, Learning-Related Emotions and Academic Achievement.

    PubMed

    Lüftenegger, Marko; Klug, Julia; Harrer, Katharina; Langer, Marie; Spiel, Christiane; Schober, Barbara

    2016-01-01

    In the present research, the recently proposed 3 × 2 model of achievement goals is tested and associations with achievement emotions and their joint influence on academic achievement are investigated. The study was conducted with 388 students using the 3 × 2 Achievement Goal Questionnaire including the six proposed goal constructs (task-approach, task-avoidance, self-approach, self-avoidance, other-approach, other-avoidance) and the enjoyment and boredom scales from the Achievement Emotion Questionnaire. Exam grades were used as an indicator of academic achievement. Findings from CFAs provided strong support for the proposed structure of the 3 × 2 achievement goal model. Self-based goals, other-based goals and task-approach goals predicted enjoyment. Task-approach goals negatively predicted boredom. Task-approach and other-approach predicted achievement. The indirect effects of achievement goals through emotion variables on achievement were assessed using bias-corrected bootstrapping. No mediation effects were found. Implications for educational practice are discussed. PMID:27199836

  9. Students’ Achievement Goals, Learning-Related Emotions and Academic Achievement

    PubMed Central

    Lüftenegger, Marko; Klug, Julia; Harrer, Katharina; Langer, Marie; Spiel, Christiane; Schober, Barbara

    2016-01-01

    In the present research, the recently proposed 3 × 2 model of achievement goals is tested and associations with achievement emotions and their joint influence on academic achievement are investigated. The study was conducted with 388 students using the 3 × 2 Achievement Goal Questionnaire including the six proposed goal constructs (task-approach, task-avoidance, self-approach, self-avoidance, other-approach, other-avoidance) and the enjoyment and boredom scales from the Achievement Emotion Questionnaire. Exam grades were used as an indicator of academic achievement. Findings from CFAs provided strong support for the proposed structure of the 3 × 2 achievement goal model. Self-based goals, other-based goals and task-approach goals predicted enjoyment. Task-approach goals negatively predicted boredom. Task-approach and other-approach predicted achievement. The indirect effects of achievement goals through emotion variables on achievement were assessed using bias-corrected bootstrapping. No mediation effects were found. Implications for educational practice are discussed. PMID:27199836

  10. Accuracy Analysis of a Low-Cost Platform for Positioning and Navigation

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Kuntzsch, C.; Schulze, M. J.; Eggert, D.; Sester, M.

    2012-07-01

    This paper presents an accuracy analysis of a platform based on low-cost components for landmark-based navigation intended for research and teaching purposes. The proposed platform includes a LEGO MINDSTORMS NXT 2.0 kit, an Android-based Smartphone as well as a compact laser scanner Hokuyo URG-04LX. The robot is used in a small indoor environment, where GNSS is not available. Therefore, a landmark map was produced in advance, with the landmark positions provided to the robot. All steps of procedure to set up the platform are shown. The main focus of this paper is the reachable positioning accuracy, which was analyzed in this type of scenario depending on the accuracy of the reference landmarks and the directional and distance measuring accuracy of the laser scanner. Several experiments were carried out, demonstrating the practically achievable positioning accuracy. To evaluate the accuracy, ground truth was acquired using a total station. These results are compared to the theoretically achievable accuracies and the laser scanner's characteristics.

  11. Advances in chemical lasers

    SciTech Connect

    Miller, D.J.

    1987-09-25

    High-power chemical lasers thrive in an array of special environments and present many fascinating associated subjects ripe for developmental research. Included are processes to produce the source reactants; supersonic mixing and reacting flow fields; the production and dissipation of multiple vibrational-rotational molecular states; optical gain extraction in complex geometries; media inhomogeneity effects, and waste energy and reaction products removal. Some configurations require wavelength selectivity, special optical components, and coherent cavity or beam combining. In recent years, progress has been made in these areas on behalf of continuous-wave and repetitively pulsed hydrogen fluoride and deuterium fluoride lasers, subsonic and supersonic oxygen-iodine lasers, and potential shorter wavelength chemical lasers based on chemically excited higher electronic states. This paper presents a brief review of the technical approach of some of the technology areas, and the status in achieving practical, integrated high-power chemical lasers.

  12. Chemical Leukoderma.

    PubMed

    Bonamonte, Domenico; Vestita, Michelangelo; Romita, Paolo; Filoni, Angela; Foti, Caterina; Angelini, Gianni

    2016-01-01

    Chemical leukoderma, often clinically mimicking idiopathic vitiligo and other congenital and acquired hypopigmentation, is an acquired form of cutaneous pigment loss caused by exposure to a variety of chemicals that act through selective melanocytotoxicity. Most of these chemicals are phenols and aromatic or aliphatic catechols derivatives. These chemicals, however, are harmful for melanocytes in individuals with an individual susceptibility. Nowadays, chemical leukoderma is fairly common, caused by common domestic products. The presence of numerous acquired confetti- or pea-sized macules is clinically characteristic of chemical leukoderma, albeit not diagnostic. Other relevant diagnostic elements are a history of repeated exposure to a known or suspected depigmenting agent at the sites of onset and a macules distribution corresponding to sites of chemical exposure. Spontaneous repigmentation has been reported when the causative agent is avoided; the repigmentation process is perifollicular and gradual, taking place for a variable period of weeks to months. PMID:27172302

  13. Low-dose cardiac imaging: reducing exposure but not accuracy.

    PubMed

    Small, Gary R; Chow, Benjamin J W; Ruddy, Terrence D

    2012-01-01

    Cardiac imaging techniques that use ionizing radiation have become an integral part of current cardiology practice. However, concern has arisen that ionizing radiation exposure, even at the low levels used for medical imaging, is associated with the risk of cancer. From a single diagnostic cardiac imaging procedure, such risks are low. On a population basis, however, malignancies become more likely on account of stochastic effects being more probable as the number of procedures performed increases. In light of this, and owing to professional and industrial commitment to the as low as reasonably achievable (ALARA) principle, over the last decade major strides have been made to reduce radiation dose in cardiac imaging. Dose-reduction strategies have been most pronounced in cardiac computed tomography. This was important since computed tomography has rapidly become a widely used diagnostic alternative to invasive coronary angiography, and initial protocols were associated with relatively high radiation exposures. Advances have also been made in nuclear cardiology and in invasive coronary angiography, and these reductions in patient exposure have all been achieved with maintenance of image quality and accuracy. Improvements in imaging camera technology, image acquisition protocols and image processing have lead to reductions in patient radiation exposure without compromising imaging diagnostic accuracy. PMID:22149528

  14. Achievement as Resistance: The Development of a Critical Race Achievement Ideology among Black Achievers

    ERIC Educational Resources Information Center

    Carter, Dorinda J.

    2008-01-01

    In this article, Dorinda Carter examines the embodiment of a critical race achievement ideology in high-achieving black students. She conducted a yearlong qualitative investigation of the adaptive behaviors that nine high-achieving black students developed and employed to navigate the process of schooling at an upper-class, predominantly white,…

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

    PubMed

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

    2016-09-13

    We introduce a method to evaluate the relative populations of different conformers of molecular species in solution, aiming at quantum mechanical accuracy, while keeping the computational cost at a nearly molecular-mechanics level. This goal is achieved by combining long classical molecular-dynamics simulations to sample the free-energy landscape of the system, advanced clustering techniques to identify the most relevant conformers, and thermodynamic perturbation theory to correct the resulting populations, using quantum-mechanical energies from density functional theory. A quantitative criterion for assessing the accuracy thus achieved is proposed. The resulting methodology is demonstrated in the specific case of cyanin (cyanidin-3-glucoside) in water solution. PMID:27494227

  16. Accuracy of stream habitat interpolations across spatial scales

    USGS Publications Warehouse

    Sheehan, Kenneth R.; Welsh, Stuart

    2013-01-01

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

  17. Accuracy of polyp localization at colonoscopy

    PubMed Central

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

    2016-01-01

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

  18. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

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

  19. Accuracy metrics for judging time scale algorithms

    NASA Technical Reports Server (NTRS)

    Douglas, R. J.; Boulanger, J.-S.; Jacques, C.

    1994-01-01

    Time scales have been constructed in different ways to meet the many demands placed upon them for time accuracy, frequency accuracy, long-term stability, and robustness. Usually, no single time scale is optimum for all purposes. In the context of the impending availability of high-accuracy intermittently-operated cesium fountains, we reconsider the question of evaluating the accuracy of time scales which use an algorithm to span interruptions of the primary standard. We consider a broad class of calibration algorithms that can be evaluated and compared quantitatively for their accuracy in the presence of frequency drift and a full noise model (a mixture of white PM, flicker PM, white FM, flicker FM, and random walk FM noise). We present the analytic techniques for computing the standard uncertainty for the full noise model and this class of calibration algorithms. The simplest algorithm is evaluated to find the average-frequency uncertainty arising from the noise of the cesium fountain's local oscillator and from the noise of a hydrogen maser transfer-standard. This algorithm and known noise sources are shown to permit interlaboratory frequency transfer with a standard uncertainty of less than 10(exp -15) for periods of 30-100 days.

  20. Activity monitor accuracy in persons using canes.

    PubMed

    Wendland, Deborah Michael; Sprigle, Stephen H

    2012-01-01

    The StepWatch activity monitor has not been validated on multiple indoor and outdoor surfaces in a population using ambulation aids. The aims of this technical report are to report on strategies to configure the StepWatch activity monitor on subjects using a cane and to report the accuracy of both leg-mounted and cane-mounted StepWatch devices on people ambulating over different surfaces while using a cane. Sixteen subjects aged 67 to 85 yr (mean 75.6) who regularly use a cane for ambulation participated. StepWatch calibration was performed by adjusting sensitivity and cadence. Following calibration optimization, accuracy was tested on both the leg-mounted and cane-mounted devices on different surfaces, including linoleum, sidewalk, grass, ramp, and stairs. The leg-mounted device had an accuracy of 93.4% across all surfaces, while the cane-mounted device had an aggregate accuracy of 84.7% across all surfaces. Accuracy of the StepWatch on the stairs was significantly less accurate (p < 0.001) when comparing surfaces using repeated measures analysis of variance. When monitoring community mobility, placement of a StepWatch on a person and his/her ambulation aid can accurately document both activity and device use. PMID:23341318

  1. Asymptotic accuracy of two-class discrimination

    SciTech Connect

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

    1994-12-31

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

  2. [Chemical weapons and chemical terrorism].

    PubMed

    Nakamura, Katsumi

    2005-10-01

    Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary. PMID:16296384

  3. A bootstrap method for assessing classification accuracy and confidence for agricultural land use mapping in Canada

    NASA Astrophysics Data System (ADS)

    Champagne, Catherine; McNairn, Heather; Daneshfar, Bahram; Shang, Jiali

    2014-06-01

    Land cover and land use classifications from remote sensing are increasingly becoming institutionalized framework data sets for monitoring environmental change. As such, the need for robust statements of classification accuracy is critical. This paper describes a method to estimate confidence in classification model accuracy using a bootstrap approach. Using this method, it was found that classification accuracy and confidence, while closely related, can be used in complementary ways to provide additional information on map accuracy and define groups of classes and to inform the future reference sampling strategies. Overall classification accuracy increases with an increase in the number of fields surveyed, where the width of classification confidence bounds decreases. Individual class accuracies and confidence were non-linearly related to the number of fields surveyed. Results indicate that some classes can be estimated accurately and confidently with fewer numbers of samples, whereas others require larger reference data sets to achieve satisfactory results. This approach is an improvement over other approaches for estimating class accuracy and confidence as it uses repetitive sampling to produce a more realistic estimate of the range in classification accuracy and confidence that can be obtained with different reference data inputs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  5. The Mechanics of Human Achievement

    PubMed Central

    Duckworth, Angela L.; Eichstaedt, Johannes C.; Ungar, Lyle H.

    2015-01-01

    Countless studies have addressed why some individuals achieve more than others. Nevertheless, the psychology of achievement lacks a unifying conceptual framework for synthesizing these empirical insights. We propose organizing achievement-related traits by two possible mechanisms of action: Traits that determine the rate at which an individual learns a skill are talent variables and can be distinguished conceptually from traits that determine the effort an individual puts forth. This approach takes inspiration from Newtonian mechanics: achievement is akin to distance traveled, effort to time, skill to speed, and talent to acceleration. A novel prediction from this model is that individual differences in effort (but not talent) influence achievement (but not skill) more substantially over longer (rather than shorter) time intervals. Conceptualizing skill as the multiplicative product of talent and effort, and achievement as the multiplicative product of skill and effort, advances similar, but less formal, propositions by several important earlier thinkers. PMID:26236393

  6. Unmet Promise: Raising Minority Achievement. The Achievement Gap.

    ERIC Educational Resources Information Center

    Johnston, Robert C.; Viadero, Debra

    2000-01-01

    This first in a four-part series on why academic achievement gaps persist discusses how to raise minority achievement. It explains how earlier progress in closing the gap has stalled, while at the same time, the greater diversity of student populations and the rapid growth of the Hispanic population and of other ethnic groups have reshaped the…

  7. To Achieve or Not to Achieve: The Question of Women.

    ERIC Educational Resources Information Center

    Gilmore, Beatrice

    Questionnaire and projective data from 323 women aged 18 to 50 were analyzed in order to study the relationships of need achievement and motive to avoid success to age, sex role ideology, and stage in the family cycle. Family background and educational variables were also considered. Level of need achievement was found to be significantly related…

  8. Mathematics Achievement in High- and Low-Achieving Secondary Schools

    ERIC Educational Resources Information Center

    Mohammadpour, Ebrahim; Shekarchizadeh, Ahmadreza

    2015-01-01

    This paper identifies the amount of variance in mathematics achievement in high- and low-achieving schools that can be explained by school-level factors, while controlling for student-level factors. The data were obtained from 2679 Iranian eighth graders who participated in the 2007 Trends in International Mathematics and Science Study. Of the…

  9. Chemical microsensors

    DOEpatents

    Li, DeQuan; Swanson, Basil I.

    1995-01-01

    An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

  10. Decreased interoceptive accuracy following social exclusion.

    PubMed

    Durlik, Caroline; Tsakiris, Manos

    2015-04-01

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

  11. Training in timing improves accuracy in golf.

    PubMed

    Libkuman, Terry M; Otani, Hajime; Steger, Neil

    2002-01-01

    In this experiment, the authors investigated the influence of training in timing on performance accuracy in golf. During pre- and posttesting, 40 participants hit golf balls with 4 different clubs in a golf course simulator. The dependent measure was the distance in feet that the ball ended from the target. Between the pre- and posttest, participants in the experimental condition received 10 hr of timing training with an instrument that was designed to train participants to tap their hands and feet in synchrony with target sounds. The participants in the control condition read literature about how to improve their golf swing. The results indicated that the participants in the experimental condition significantly improved their accuracy relative to the participants in the control condition, who did not show any improvement. We concluded that training in timing leads to improvement in accuracy, and that our results have implications for training in golf as well as other complex motor activities. PMID:12038497

  12. Affective Processes and Academic Achievement.

    ERIC Educational Resources Information Center

    Feshbach, Norma Deitch; Feshbach, Seymour

    1987-01-01

    Data indicate that for girls, affective dispositional factors (empathy, depressive affectivity, aggression, and self-concept) are intimately linked to cognitive development and academic achievement. (PCB)

  13. Attribution theory in science achievement

    NASA Astrophysics Data System (ADS)

    Craig, Martin

    Recent research reveals consistent lags in American students' science achievement scores. Not only are the scores lower in the United States compared to other developed nations, but even within the United States, too many students are well below science proficiency scores for their grade levels. The current research addresses this problem by examining potential malleable factors that may predict science achievement in twelfth graders using 2009 data from the National Assessment of Educational Progress (NAEP). Principle component factor analysis was conducted to determine the specific items that contribute to each overall factor. A series of multiple regressions were then analyzed and formed the predictive value of each of these factors for science achievement. All significant factors were ultimately examined together (also using multiple regression) to determine the most powerful predictors of science achievement, identifying factors that predict science achievement, the results of which suggested interventions to strengthen students' science achievement scores and encourage persistence in the sciences at the college level and beyond. Although there is a variety of research highlighting how students in the US are falling behind other developing nations in science and math achievement, as yet, little research has addressed ways of intervening to address this gap. The current research is a starting point, seeking to identify malleable factors that contribute to science achievement. More specifically, this research examined the types of attributions that predict science achievement in twelfth grade students.

  14. Physics of a ballistic missile defense - The chemical laser boost-phase defense

    NASA Technical Reports Server (NTRS)

    Grabbe, Crockett L.

    1988-01-01

    The basic physics involved in proposals to use a chemical laser based on satellites for a boost-phase defense are investigated. After a brief consideration of simple physical conditions for the defense, a calculation of an equation for the number of satellites needed for the defense is made along with some typical values of this for possible future conditions for the defense. Basic energy and power requirements for the defense are determined. A sumary is made of probable minimum conditions that must be achieved for laser power, targeting accuracy, number of satellites, and total sources for power needed.

  15. Optimal sampling schedule for chemical exchange saturation transfer.

    PubMed

    Tee, Y K; Khrapitchev, A A; Sibson, N R; Payne, S J; Chappell, M A

    2013-11-01

    The sampling schedule for chemical exchange saturation transfer imaging is normally uniformly distributed across the saturation frequency offsets. When this kind of evenly distributed sampling schedule is used to quantify the chemical exchange saturation transfer effect using model-based analysis, some of the collected data are minimally informative to the parameters of interest. For example, changes in labile proton exchange rate and concentration mainly affect the magnetization near the resonance frequency of the labile pool. In this study, an optimal sampling schedule was designed for a more accurate quantification of amine proton exchange rate and concentration, and water center frequency shift based on an algorithm previously applied to magnetization transfer and arterial spin labeling. The resulting optimal sampling schedule samples repeatedly around the resonance frequency of the amine pool and also near to the water resonance to maximize the information present within the data for quantitative model-based analysis. Simulation and experimental results on tissue-like phantoms showed that greater accuracy and precision (>30% and >46%, respectively, for some cases) were achieved in the parameters of interest when using optimal sampling schedule compared with evenly distributed sampling schedule. Hence, the proposed optimal sampling schedule could replace evenly distributed sampling schedule in chemical exchange saturation transfer imaging to improve the quantification of the chemical exchange saturation transfer effect and parameter estimation. PMID:23315799

  16. Final Technical Report: Increasing Prediction Accuracy.

    SciTech Connect

    King, Bruce Hardison; Hansen, Clifford; Stein, Joshua

    2015-12-01

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

  17. The accuracy of Halley's cometary orbits

    NASA Astrophysics Data System (ADS)

    Hughes, D. W.

    The accuracy of a scientific computation depends in the main on the data fed in and the analysis method used. This statement is certainly true of Edmond Halley's cometary orbit work. Considering the 420 comets that had been seen before Halley's era of orbital calculation (1695 - 1702) only 24, according to him, had been observed well enough for their orbits to be calculated. Two questions are considered in this paper. Do all the orbits listed by Halley have the same accuracy? and, secondly, how accurate was Halley's method of calculation?

  18. Accuracy in Quantitative 3D Image Analysis

    PubMed Central

    Bassel, George W.

    2015-01-01

    Quantitative 3D imaging is becoming an increasingly popular and powerful approach to investigate plant growth and development. With the increased use of 3D image analysis, standards to ensure the accuracy and reproducibility of these data are required. This commentary highlights how image acquisition and postprocessing can introduce artifacts into 3D image data and proposes steps to increase both the accuracy and reproducibility of these analyses. It is intended to aid researchers entering the field of 3D image processing of plant cells and tissues and to help general readers in understanding and evaluating such data. PMID:25804539

  19. Charge Detection Mass Spectrometry with Almost Perfect Charge Accuracy.

    PubMed

    Keifer, David Z; Shinholt, Deven L; Jarrold, Martin F

    2015-10-20

    Charge detection mass spectrometry (CDMS) is a single-particle technique where the masses of individual ions are determined from simultaneous measurement of each ion's mass-to-charge ratio (m/z) and charge. CDMS has many desirable features: it has no upper mass limit, no mass discrimination, and it can analyze complex mixtures. However, the charge is measured directly, and the poor accuracy of the charge measurement has severely limited the mass resolution achievable with CDMS. Since the charge is quantized, it needs to be measured with sufficient accuracy to assign each ion to its correct charge state. This goal has now been largely achieved. By reducing the pressure to extend the trapping time and by implementing a novel analysis method that improves the signal-to-noise ratio and compensates for imperfections in the charge measurement, the uncertainty has been reduced to less than 0.20 e rmsd (root-mean-square deviation). With this unprecedented precision peaks due to different charge states are resolved in the charge spectrum. Further improvement can be achieved by quantizing the charge (rounding the measured charge to the nearest integer) and culling ions with measured charges midway between the integral values. After ions with charges more than one standard deviation from the mean are culled, the fraction of ions assigned to the wrong charge state is estimated to be 6.4 × 10(-5) (i.e., less than 1 in 15 000). Since almost all remaining ions are assigned to their correct charge state, the uncertainty in the mass is now almost entirely limited by the uncertainty in the m/z measurement. PMID:26418830

  20. Gas Phase Chemical Detection with an Integrated Chemical Analysis System

    SciTech Connect

    Baca, Albert G.; Casalnuovo, Stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Susan L.; Hietala, Vincent M.; Kottenstette, Richard J.; Lewis, Patrick R.; Manginell, Ronald P.; Matzke, Carloyn M.; Reno, John L.; Sasaki, Darryl Y.; Schubert, W. Kent

    1999-07-08

    Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample concentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described. The design and performance of novel micromachined acoustic wave devices, with the potential for improved chemical sensitivity, are also described.

  1. Accuracy of dental radiographs for caries detection.

    PubMed

    Keenan, James R; Keenan, Analia Veitz

    2016-06-01

    Data sourcesMedline, Embase, Cochrane Central and grey literature, complemented by cross-referencing from bibliographies. Diagnostic reviews were searched using the Medion database.Study selectionStudies reporting on the accuracy (sensitivity/specificity) of radiographic detection of primary carious lesions under clinical (in vivo) or in vitro conditions were included. The outcome of interest was caries detection using radiographs. The study also assessed the effect of the histologic lesion stage and included articles to assess the differences between primary or permanent teeth, if there had been improvements recently due to technical advances or radiographic methods, or if there are variations within studies (between examiners or applied radiographic techniques).Data extraction and synthesisData extraction was done by one reviewer first, using a piloted electronic spreadsheet and repeated independently by a second reviewer. Consensus was achieved by discussion. Data extraction followed guidelines from the Cochrane Collaboration. Risk of bias was assessed using QUADAS-2. Pooled sensitivity, specificity and diagnostic odds ratios (DORs) were calculated using random effects meta-analysis. Analyses were performed separately for occlusal and proximal lesions. Dentine lesions and cavitated lesions were analysed separately.Results947 articles were identified with the searches and 442 were analysed full text. 117 studies (13,375 teeth, 19,108 surfaces) were included. All studies were published in English. 24 studies were in vivo and 93 studies were in vitro. Risk of bias was found to be low in 23 and high in 94 studies. The pooled sensitivity for detecting any kind of occlusal carious lesions was 0.35 (95% CI : 0.31/40) and 0.41 (0.39/0.44) in clinical and in vitro studies respectively while the pooled specificity was 0.78 (0.73/0.83) and 0.70 (0.76/0.84). For the detection of any kind of proximal lesion the sensitivity in the clinical studies was 0.24 (CI 0.21/0/26) and

  2. Assessment of Weighted Quantile Sum Regression for Modeling Chemical Mixtures and Cancer Risk

    PubMed Central

    Czarnota, Jenna; Gennings, Chris; Wheeler, David C

    2015-01-01

    In evaluation of cancer risk related to environmental chemical exposures, the effect of many chemicals on disease is ultimately of interest. However, because of potentially strong correlations among chemicals that occur together, traditional regression methods suffer from collinearity effects, including regression coefficient sign reversal and variance inflation. In addition, penalized regression methods designed to remediate collinearity may have limitations in selecting the truly bad actors among many correlated components. The recently proposed method of weighted quantile sum (WQS) regression attempts to overcome these problems by estimating a body burden index, which identifies important chemicals in a mixture of correlated environmental chemicals. Our focus was on assessing through simulation studies the accuracy of WQS regression in detecting subsets of chemicals associated with health outcomes (binary and continuous) in site-specific analyses and in non-site-specific analyses. We also evaluated the performance of the penalized regression methods of lasso, adaptive lasso, and elastic net in correctly classifying chemicals as bad actors or unrelated to the outcome. We based the simulation study on data from the National Cancer Institute Surveillance Epidemiology and End Results Program (NCI-SEER) case–control study of non-Hodgkin lymphoma (NHL) to achieve realistic exposure situations. Our results showed that WQS regression had good sensitivity and specificity across a variety of conditions considered in this study. The shrinkage methods had a tendency to incorrectly identify a large number of components, especially in the case of strong association with the outcome. PMID:26005323

  3. ASSESSMENT OF THE PRECISION AND ACCURACY OF SAM AND MFC MICROCOSMS EXPOSED TO TOXICANTS

    EPA Science Inventory

    The results of 30 mixed flank culture (MFC) and four standardized aquatic microcosm (SAM) microcosm experiments were used to describe the precision and accuracy of these two protocols. oefficients of variation (CV) for chemicals measurements (DO,pH) were generally less than 7%, f...

  4. Using Force-Matched Potentials To Improve the Accuracy of Density Functional Tight Binding for Reactive Conditions

    NASA Astrophysics Data System (ADS)

    Goldman, Nir

    In this work, we show that force matching can be used to determine accurate density functional tight binding (DFTB) models for reactive materials under extreme conditions. Determination of chemical reactivity in high-pressure experiments is an unsolved problem that can span timescales orders of magnitude longer that what can be achieved with standard quantum simulation approaches, such as Kohn-Sham Density Functional Theory. DFTB holds promise as a semi-empirical quantum simulation method that yields a high degree of computational efficiency while potentially retaining the accuracy of these higher order methods. Here, we show that force matching can be used to determine accurate repulsive energies for DFTB for chemical reactivity in condensed phases. Our new models yield improved predictions for physical properties of molten liquid carbon, as well as small molecule production in phenolic polymer combustion. Our approach is general and can be implemented as a way to extend quantum simulations to several orders of magnitude longer timescales than previously possible, allowing for direct comparison with experiments.

  5. Parametric design methodology for chemical processes using a simulator

    SciTech Connect

    Diwekar, U.M.; Rubin, E.S. )

    1994-02-01

    Parameter design is a method popularized by the Japanese quality expert G. Taguchi, for designing products and manufacturing processes that are robust in the face of uncontrollable variations. At the design stage, the goal of parameter design is to identify design settings that make the product performance less sensitive to the effects of manufacturing and environmental variations and deterioration. Because parameter design reduces performance variation by reducing the influence of the sources of variation rather than by controlling them, it is a cost-effective technique for improving quality. A recent study on the application of parameter design methodology for chemical processes reported that the use of Taguchi's method was not justified and a method based on Monte Carlo simulation combined with optimization was shown to be more effective. However, this method is computationally intensive as a large number of samples are necessary to achieve the given accuracy. Additionally, determination of the number of sample runs required is based on experimentation due to a lack of systematic sampling methods. In an attempt to overcome these problems, the use of a stochastic modeling capability combined with an optimizer is presented in this paper. The objective is that of providing an effective means for application of parameter design methodologies to chemical processes using the ASPEN simulator. This implementation not only presents a generalized tool for use by chemical engineers at large but also provides systematic estimates of the number of sample runs required to attain the specified accuracy. The stochastic model employs the technique of Latin hypercube sampling instead of the traditional Monte Carlo technique and hence has a great potential to reduce the required number of samples. The methodology is illustrated via an example problem of designing a chemical process.

  6. Reduction of chemical reaction networks through delay distributions

    NASA Astrophysics Data System (ADS)

    Barrio, Manuel; Leier, André; Marquez-Lago, Tatiana T.

    2013-03-01

    Accurate modelling and simulation of dynamic cellular events require two main ingredients: an adequate description of key chemical reactions and simulation of such chemical events in reasonable time spans. Quite logically, posing the right model is a crucial step for any endeavour in Computational Biology. However, more often than not, it is the associated computational costs which actually limit our capabilities of representing complex cellular behaviour. In this paper, we propose a methodology aimed at representing chains of chemical reactions by much simpler, reduced models. The abridgement is achieved by generation of model-specific delay distribution functions, consecutively fed to a delay stochastic simulation algorithm. We show how such delay distributions can be analytically described whenever the system is solely composed of consecutive first-order reactions, with or without additional "backward" bypass reactions, yielding an exact reduction. For models including other types of monomolecular reactions (constitutive synthesis, degradation, or "forward" bypass reactions), we discuss why one must adopt a numerical approach for its accurate stochastic representation, and propose two alternatives for this. In these cases, the accuracy depends on the respective numerical sample size. Our model reduction methodology yields significantly lower computational costs while retaining accuracy. Quite naturally, computational costs increase alongside network size and separation of time scales. Thus, we expect our model reduction methodologies to significantly decrease computational costs in these instances. We anticipate the use of delays in model reduction will greatly alleviate some of the current restrictions in simulating large sets of chemical reactions, largely applicable in pharmaceutical and biological research.

  7. General Achievement Trends: South Dakota

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  8. The Process of Science Achievement.

    ERIC Educational Resources Information Center

    Papanastasiou, Constantinos; Papanastasiou, Elena C.

    2002-01-01

    Investigates the science achievement of 8th grade students in Cyprus by using a structural equation model with three exogenous constructs--family's educational background, reinforcements, and school climate, and three endogenous constructs--teaching, student attitudes, and achievement. Proposes a model for the effects of family, school, student…

  9. Examination Regimes and Student Achievement

    ERIC Educational Resources Information Center

    Cosentino de Cohen, Clemencia

    2010-01-01

    Examination regimes at the end of secondary school vary greatly intra- and cross-nationally, and in recent years have undergone important reforms often geared towards increasing student achievement. This research presents a comparative analysis of the relationship between examination regimes and student achievement in the OECD. Using a micro…

  10. School Size and Student Achievement

    ERIC Educational Resources Information Center

    Riggen, Vicki

    2013-01-01

    This study examined whether a relationship between high school size and student achievement exists in Illinois public high schools in reading and math, as measured by the Prairie State Achievement Exam (PSAE), which is administered to all Illinois 11th-grade students. This study also examined whether the factors of socioeconomic status, English…

  11. Motivational Factors in School Achievement.

    ERIC Educational Resources Information Center

    Maehr, Martin L.

    A summary is presented of the literature on motivation relating to achievement in the classroom. Special attention is given to how values, ideology, and various cultural patterns may serve to enhance motivation to achieve in the classroom. In considering what determines motivation and personal investment in educational pursuits, the following…

  12. Parental Involvement and Academic Achievement

    ERIC Educational Resources Information Center

    Goodwin, Sarah Christine

    2015-01-01

    This research study examined the correlation between student achievement and parent's perceptions of their involvement in their child's schooling. Parent participants completed the Parent Involvement Project Parent Questionnaire. Results slightly indicated parents of students with higher level of achievement perceived less demand or invitations…

  13. General Achievement Trends: New Jersey

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  14. General Achievement Trends: North Carolina

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  15. Perils of Standardized Achievement Testing

    ERIC Educational Resources Information Center

    Haladyna, Thomas M.

    2006-01-01

    This article argues that the validity of standardized achievement test-score interpretation and use is problematic; consequently, confidence and trust in such test scores may often be unwarranted. The problem is particularly severe in high-stakes situations. This essay provides a context for understanding standardized achievement testing, then…

  16. Raising Boys' Achievement in Schools.

    ERIC Educational Resources Information Center

    Bleach, Kevan, Ed.

    This book offers insights into the range of strategies and good practice being used to raise the achievement of boys. Case studies by school-based practitioners suggest ideas and measures to address the issue of achievement by boys. The contributions are: (1) "Why the Likely Lads Lag Behind" (Kevan Bleach); (2) "Helping Boys Do Better in Their…

  17. Stress Correlates and Academic Achievement.

    ERIC Educational Resources Information Center

    Bentley, Donna Anderson; And Others

    An ongoing concern for educators is the identification of factors that contribute to or are associated with academic achievement; one such group of variables that has received little attention are those involving stress. The relationship between perceived sources of stress and academic achievement was examined to determine if reactions to stress…

  18. Achievement in Writing Geometry Proofs.

    ERIC Educational Resources Information Center

    Senk, Sharon L.

    In 1981 a nationwide assessment of achievement in writing geometry proofs was conducted by the Cognitive Development and Achievement in Secondary School Geometry project. Over 1,500 students in 11 schools in 5 states participated. This paper describes the sample, instruments, grading procedures, and selected results. Results include: (1) at the…

  19. Teaching the Low Level Achiever.

    ERIC Educational Resources Information Center

    Salomone, Ronald E., Ed.

    1986-01-01

    Intended for teachers of the English language arts, the articles in this issue offer suggestions and techniques for teaching the low level achiever. Titles and authors of the articles are as follows: (1) "A Point to Ponder" (Rachel Martin); (2) "Tracking: A Self-Fulfilling Prophecy of Failure for the Low Level Achiever" (James Christopher Davis);…

  20. Predicting Achievement in Foreign Language.

    ERIC Educational Resources Information Center

    Hart, Mary Elizabeth

    A review of research is inconclusive concerning the relationship between intelligence and language proficiency. A study of 10th grade students (n=35) examined scores on a high school entrance exam and achievement in foreign language after 1 year of study. Both math and reading showed a significant correlation with foreign language achievement; the…

  1. Superintendent Tenure and Student Achievement

    ERIC Educational Resources Information Center

    Simpson, Jennifer

    2013-01-01

    A correlational research design was used to examine the influence of superintendent tenure on student achievement in rural Appalachian Kentucky school districts. Superintendent tenure was compared to aggregated student achievement scores for 2011 and to changes in students' learning outcomes over the course of the superintendents' tenure. The…

  2. Chemical preconcentrator

    DOEpatents

    Manginell, Ronald P.; Frye-Mason, Gregory C.

    2001-01-01

    A chemical preconcentrator is disclosed with applications to chemical sensing and analysis. The preconcentrator can be formed by depositing a resistive heating element (e.g. platinum) over a membrane (e.g. silicon nitride) suspended above a substrate. A coating of a sorptive material (e.g. a microporous hydrophobic sol-gel coating or a polymer coating) is formed on the suspended membrane proximate to the heating element to selective sorb one or more chemical species of interest over a time period, thereby concentrating the chemical species in the sorptive material. Upon heating the sorptive material with the resistive heating element, the sorbed chemical species are released for detection and analysis in a relatively high concentration and over a relatively short time period. The sorptive material can be made to selectively sorb particular chemical species of interest while not substantially sorbing other chemical species not of interest. The present invention has applications for use in forming high-sensitivity, rapid-response miniaturized chemical analysis systems (e.g. a "chem lab on a chip").

  3. Chemical sensors

    DOEpatents

    Lowell, Jr., James R.; Edlund, David J.; Friesen, Dwayne T.; Rayfield, George W.

    1991-01-01

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising (a) a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, operatively coupled to (b) a transducer capable of directly converting said expansion or contraction to a measurable electrical response.

  4. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  5. Chemical Peels

    MedlinePlus

    ... the complications or potential side effects of a chemical peel? Temporary or permanent change in skin color, particularly for women on birth control pills, who subsequently become pregnant or have a history of brownish facial ... after having a chemical peel? All peels require some follow-up care: ...

  6. Chemical Emergencies

    MedlinePlus

    ... agents such as sarin and VX. Many hazardous chemicals are used in industry - for example, chlorine, ammonia, and benzene. Some can be made from everyday items such as household cleaners. Although there are no guarantees of safety during a chemical emergency, you can take actions to protect yourself. ...

  7. Speed-Accuracy Response Models: Scoring Rules Based on Response Time and Accuracy

    ERIC Educational Resources Information Center

    Maris, Gunter; van der Maas, Han

    2012-01-01

    Starting from an explicit scoring rule for time limit tasks incorporating both response time and accuracy, and a definite trade-off between speed and accuracy, a response model is derived. Since the scoring rule is interpreted as a sufficient statistic, the model belongs to the exponential family. The various marginal and conditional distributions…

  8. High Accuracy Transistor Compact Model Calibrations

    SciTech Connect

    Hembree, Charles E.; Mar, Alan; Robertson, Perry J.

    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.

  9. Direct Behavior Rating: Considerations for Rater Accuracy

    ERIC Educational Resources Information Center

    Harrison, Sayward E.; Riley-Tillman, T. Chris; Chafouleas, Sandra M.

    2014-01-01

    Direct behavior rating (DBR) offers users a flexible, feasible method for the collection of behavioral data. Previous research has supported the validity of using DBR to rate three target behaviors: academic engagement, disruptive behavior, and compliance. However, the effect of the base rate of behavior on rater accuracy has not been established.…

  10. Vowel Space Characteristics and Vowel Identification Accuracy

    ERIC Educational Resources Information Center

    Neel, Amy T.

    2008-01-01

    Purpose: To examine the relation between vowel production characteristics and intelligibility. Method: Acoustic characteristics of 10 vowels produced by 45 men and 48 women from the J. M. Hillenbrand, L. A. Getty, M. J. Clark, and K. Wheeler (1995) study were examined and compared with identification accuracy. Global (mean f0, F1, and F2;…

  11. Seasonal Effects on GPS PPP Accuracy

    NASA Astrophysics Data System (ADS)

    Saracoglu, Aziz; Ugur Sanli, D.

    2016-04-01

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

  12. Accuracy Assessment for AG500, Electromagnetic Articulograph

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Mefferd, Antje

    2009-01-01

    Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…

  13. 47 CFR 65.306 - Calculation accuracy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Calculation accuracy. 65.306 Section 65.306 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERSTATE RATE OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Exchange Carriers § 65.306 Calculation...

  14. Navigation Accuracy Guidelines for Orbital Formation Flying

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Alfriend, Kyle T.

    2004-01-01

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

  15. Accuracy of Information Processing under Focused Attention.

    ERIC Educational Resources Information Center

    Bastick, Tony

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

  16. Observed Consultation: Confidence and Accuracy of Assessors

    ERIC Educational Resources Information Center

    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…

  17. Accuracy of References in Five Entomology Journals.

    ERIC Educational Resources Information Center

    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…

  18. 47 CFR 65.306 - Calculation accuracy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Calculation accuracy. 65.306 Section 65.306 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERSTATE RATE OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Exchange Carriers § 65.306 Calculation...

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

    PubMed

    Mattijssen, Erwin J A T; Kerkhoff, Wim

    2016-05-01

    Based on the spatial relation between a primary and secondary bullet defect or on the shape and dimensions of the primary bullet defect, a bullet's trajectory prior to impact can be estimated for a shooting scene reconstruction. The accuracy and precision of the estimated trajectories will vary depending on variables such as, the applied method of reconstruction, the (true) angle of incidence, the properties of the target material and the properties of the bullet upon impact. This study focused on the accuracy and precision of estimated bullet trajectories when different variants of the probing method, ellipse method, and lead-in method are applied on bullet defects resulting from shots at various angles of incidence on drywall, MDF and sheet metal. The results show that in most situations the best performance (accuracy and precision) is seen when the probing method is applied. Only for the lowest angles of incidence the performance was better when either the ellipse or lead-in method was applied. The data provided in this paper can be used to select the appropriate method(s) for reconstruction and to correct for systematic errors (accuracy) and to provide a value of the precision, by means of a confidence interval of the specific measurement. PMID:27044032

  20. Measuring Tracking Accuracy of CCD Imagers

    NASA Technical Reports Server (NTRS)

    Stanton, R. H.; Dennison, E. W.

    1985-01-01

    Tracking accuracy and resolution of charge-coupled device (CCD) imaging arrays measured by instrument originally developed for measuring performance of star-tracking telescope. Operates by projecting one or more artifical star images on surface of CCD array, moving stars in controlled patterns, and comparing star locations computed from CCD outputs with those calculated from step coordinates of micropositioner.

  1. Accuracy of Digital vs. Conventional Implant Impressions

    PubMed Central

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

    2015-01-01

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

  2. Analyzing thematic maps and mapping for accuracy

    USGS Publications Warehouse

    Rosenfield, G.H.

    1982-01-01

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

  3. The impact of accuracy motivation on interpretation, comparison, and correction processes: accuracy x knowledge accessibility effects.

    PubMed

    Stapel, D A; Koomen, W; Zeelenberg, M

    1998-04-01

    Four studies provide evidence for the notion that there may be boundaries to the extent to which accuracy motivation may help perceivers to escape the influence of fortuitously activated information. Specifically, although accuracy motivations may eliminate assimilative accessibility effects, they are less likely to eliminate contrastive accessibility effects. It was found that the occurrence of different types of contrast effects (comparison and correction) was not significantly affected by participants' accuracy motivations. Furthermore, it was found that the mechanisms instigated by accuracy motivations differ from those ignited by correction instructions: Accuracy motivations attenuate assimilation effects because perceivers add target interpretations to the one suggested by primed information. Conversely, it was found that correction instructions yield contrast and prompt respondents to remove the priming event's influence from their reaction to the target. PMID:9569650

  4. Analysis of deformable image registration accuracy using computational modeling.

    PubMed

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

    2010-03-01

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

  5. Diagnostic Accuracy of Fractional Flow Reserve From Anatomic CT Angiography

    PubMed Central

    Min, James K.; Leipsic, Jonathon; Pencina, Michael J.; Berman, Daniel S.; Koo, Bon-Kwon; van Mieghem, Carlos; Erglis, Andrejs; Lin, Fay Y.; Dunning, Allison M.; Apruzzese, Patricia; Budoff, Matthew J.; Cole, Jason H.; Jaffer, Farouc A.; Leon, Martin B.; Malpeso, Jennifer; John Mancini, G. B.; Park, Seung-Jung; Schwartz, Robert S.; Shaw, Leslee J.; Mauri, Laura

    2014-01-01

    with obstructive CAD diagnosed by CT alone (area under the receiver operating characteristic curve [AUC], 0.68; 95% CI, 0.62–0.74), FFRCT was associated with improved discrimination (AUC, 0.81; 95% CI, 0.75–0.86; P<.001). Conclusion Although the study did not achieve its prespecified primary outcome goal for the level of per-patient diagnostic accuracy, use of noninvasive FFRCT plus CT among stable patients with suspected or known CAD was associated with improved diagnostic accuracy and discrimination vs CT alone for the diagnosis of hemodynamically significant CAD when FFR determined at the time of ICA was the reference standard. PMID:22922562

  6. Analysis of deformable image registration accuracy using computational modeling

    SciTech Connect

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

    2010-03-15

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

  7. Audiovisual biofeedback improves motion prediction accuracy

    PubMed Central

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

    2013-01-01

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

  8. Electropulse chemical machining

    SciTech Connect

    Allen, T.A.; Rospopo, S.D.

    1984-08-01

    Electropulse Chemical Machining is a new technique in chemical milling, and we have applied it to the photoforming of molybdenum. We apply direct current in short pulses at current densities of thousands of amperes per square foot with little thermal degradation of resists or workpieces. We have achieved etch rates an order of magnitude faster than those of existing methods, with a corresponding improvement in surface finish. Equipment designed for pulse plating can be used and is readily available from plating suppliers. Chemicals are commercially available and may be diluted to levels that protect resist images, reduce hazards to personnel, and simplify disposal. We speculate that this process can be applied to other refractory metals and noble metals.

  9. The Role of Visual Mental Imagery in the Speed-Accuracy Tradeoff: A Preliminary Investigation.

    ERIC Educational Resources Information Center

    Hodes, Carol L.

    This study investigates the relationship between speed of recognition and accuracy of the responses when visual mental imagery is controlled through imagery instructions. The procedure was to compare the achievement of learners where the independent variable was imagery instructions. The subjects were two 20-person groups of undergraduates from a…

  10. Accuracy Comparison of Vhr Systematic-Ortho Satellite Imageries against Vhr Orthorectified Imageries Using Gcp

    NASA Astrophysics Data System (ADS)

    Widyaningrum, E.; Fajari, M.; Octariady, J.

    2016-06-01

    The Very High Resolution (VHR) satellite imageries such us Pleiades, WorldView-2, GeoEye-1 used for precise mapping purpose must be corrected from any distortion to achieve the expected accuracy. Orthorectification is performed to eliminate geometric errors of the VHR satellite imageries. Orthorectification requires main input data such as Digital Elevation Model (DEM) and Ground Control Point (GCP). The VHR systematic-ortho imageries were generated using SRTM 30m DEM without using any GCP data. The accuracy value differences of VHR systematic-ortho imageries and VHR orthorectified imageries using GCP currently is not exactly defined. This study aimed to identified the accuracy comparison of VHR systematic-ortho imageries against orthorectified imageries using GCP. Orthorectified imageries using GCP created by using Rigorous model. Accuracy evaluation is calculated by using several independent check points.

  11. A note on the accuracy of spectral method applied to nonlinear conservation laws

    NASA Technical Reports Server (NTRS)

    Shu, Chi-Wang; Wong, Peter S.

    1994-01-01

    Fourier spectral method can achieve exponential accuracy both on the approximation level and for solving partial differential equations if the solutions are analytic. For a linear partial differential equation with a discontinuous solution, Fourier spectral method produces poor point-wise accuracy without post-processing, but still maintains exponential accuracy for all moments against analytic functions. In this note we assess the accuracy of Fourier spectral method applied to nonlinear conservation laws through a numerical case study. We find that the moments with respect to analytic functions are no longer very accurate. However the numerical solution does contain accurate information which can be extracted by a post-processing based on Gegenbauer polynomials.

  12. Camera sensor arrangement for crop/weed detection accuracy in agronomic images.

    PubMed

    Romeo, Juan; Guerrero, José Miguel; Montalvo, Martín; Emmi, Luis; Guijarro, María; Gonzalez-de-Santos, Pablo; Pajares, Gonzalo

    2013-01-01

    In Precision Agriculture, images coming from camera-based sensors are commonly used for weed identification and crop line detection, either to apply specific treatments or for vehicle guidance purposes. Accuracy of identification and detection is an important issue to be addressed in image processing. There are two main types of parameters affecting the accuracy of the images, namely: (a) extrinsic, related to the sensor's positioning in the tractor; (b) intrinsic, related to the sensor specifications, such as CCD resolution, focal length or iris aperture, among others. Moreover, in agricultural applications, the uncontrolled illumination, existing in outdoor environments, is also an important factor affecting the image accuracy. This paper is exclusively focused on two main issues, always with the goal to achieve the highest image accuracy in Precision Agriculture applications, making the following two main contributions: (a) camera sensor arrangement, to adjust extrinsic parameters and (b) design of strategies for controlling the adverse illumination effects. PMID:23549361

  13. Camera Sensor Arrangement for Crop/Weed Detection Accuracy in Agronomic Images

    PubMed Central

    Romeo, Juan; Guerrero, José Miguel; Montalvo, Martín; Emmi, Luis; Guijarro, María; Gonzalez-de-Santos, Pablo; Pajares, Gonzalo

    2013-01-01

    In Precision Agriculture, images coming from camera-based sensors are commonly used for weed identification and crop line detection, either to apply specific treatments or for vehicle guidance purposes. Accuracy of identification and detection is an important issue to be addressed in image processing. There are two main types of parameters affecting the accuracy of the images, namely: (a) extrinsic, related to the sensor's positioning in the tractor; (b) intrinsic, related to the sensor specifications, such as CCD resolution, focal length or iris aperture, among others. Moreover, in agricultural applications, the uncontrolled illumination, existing in outdoor environments, is also an important factor affecting the image accuracy. This paper is exclusively focused on two main issues, always with the goal to achieve the highest image accuracy in Precision Agriculture applications, making the following two main contributions: (a) camera sensor arrangement, to adjust extrinsic parameters and (b) design of strategies for controlling the adverse illumination effects. PMID:23549361

  14. Incorporating tracer-tracee differences into models to improve accuracy

    SciTech Connect

    Schoeller, D.A. )

    1991-05-01

    The ideal tracer for metabolic studies is one that behaves exactly like the tracee. Compounds labeled with isotopes come the closest to this ideal because they are chemically identical to the tracee except for the substitution of a stable or radioisotope at one or more positions. Even this substitution, however, can introduce a difference in metabolism that may be quantitatively important with regard to the development of the mathematical model used to interpret the kinetic data. The doubly labeled water method for the measurement of carbon dioxide production and hence energy expenditure in free-living subjects is a good example of how differences between the metabolism of the tracers and the tracee can influence the accuracy of the carbon dioxide production rate determined from the kinetic data.

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

    PubMed

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

    2013-01-01

    Direct dynamics simulations are a very useful and general approach for studying the atomistic properties of complex chemical systems, since an electronic structure theory representation of a system's potential energy surface is possible without the need for fitting an analytic potential energy function. In this paper, recently introduced compact finite difference (CFD) schemes for approximating the Hessian [J. Chem. Phys.2010, 133, 074101] are tested by employing the monodromy matrix equations of motion. Several systems, including carbon dioxide and benzene, are simulated, using both analytic potential energy surfaces and on-the-fly direct dynamics. The results show, depending on the molecular system, that electronic structure theory Hessian direct dynamics can be accelerated up to 2 orders of magnitude. The CFD approximation is found to be robust enough to deal with chaotic motion, concomitant with floppy and stiff mode dynamics, Fermi resonances, and other kinds of molecular couplings. Finally, the CFD approximations allow parametrical tuning of different CFD parameters to attain the best possible accuracy for different molecular systems. Thus, a direct dynamics simulation requiring the Hessian at every integration step may be replaced with an approximate Hessian updating by tuning the appropriate accuracy. PMID:26589009

  16. [Cutaneous absorption of chemicals].

    PubMed

    Schröder, J

    1986-09-01

    Chemicals have become indispensible for the maintenance of health in animals and man. The route of administration of each medicament is decided by factors such as site of desired action, chemistry of the active ingredient, age and species of the patient, and frequency of administration (or desired duration of activity). In situations where the oral and hypodermic routes, which are used most frequently, are inadequate or unsatisfactory, dermal application can provide a valuable alternative method to achieve systemic activity. Examples of formulations currently available for dermal application contain diverse chemicals and are intended for a variety of purposes, such as crufomate against cattle grubs, fenthion against cattle lice, levamisole against gastrointestinal nematodes, nitroglycerine for angina pectoris, and scopolamine for motion sickness. The skin acts as a barrier to penetration by chemicals and micro-organisms by virtue of its morphology and chemical composition. Chemicals which do penetrate, do not necessarily pass through the appendages (hair follicles and gland ducts), but mostly penetrate through the interjacent epidermis, either through the cells, or via the intracellular spaces. These spaces have recently been shown by electron microscopy to be filled by an amorphous substance which exudes on the skin surface in convex ridges. This substance has a lipid nature, but is not hydrophobic as is often accepted. For a chemical to be able to penetrate the skin, it must be partially water and lipid soluble, polar, and weakly ionizing. A variety of factors can possibly affect the permeability of skin for a chemical. These include species differences in morphology (skin thickness, tightness of intercellular junctions, density of hair follicles and other appendages), biochemistry, and physiology; seasonal and climatic variations; and differences between breeds and genders. Species differences in skin permeability are largely unpredictable and inconsistent. An

  17. Childhood Obesity and Cognitive Achievement.

    PubMed

    Black, Nicole; Johnston, David W; Peeters, Anna

    2015-09-01

    Obese children tend to perform worse academically than normal-weight children. If poor cognitive achievement is truly a consequence of childhood obesity, this relationship has significant policy implications. Therefore, an important question is to what extent can this correlation be explained by other factors that jointly determine obesity and cognitive achievement in childhood? To answer this question, we exploit a rich longitudinal dataset of Australian children, which is linked to national assessments in math and literacy. Using a range of estimators, we find that obesity and body mass index are negatively related to cognitive achievement for boys but not girls. This effect cannot be explained by sociodemographic factors, past cognitive achievement or unobserved time-invariant characteristics and is robust to different measures of adiposity. Given the enormous importance of early human capital development for future well-being and prosperity, this negative effect for boys is concerning and warrants further investigation. PMID:26123250

  18. Using Design To Achieve Sustainability

    EPA Science Inventory

    Sustainability is defined as meeting the needs of this generation without compromising the ability of future generations to meet their needs. This is a conditional statement that places the responsibility for achieving sustainability squarely in hands of designers and planners....

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Potential accuracy of translation estimation between radar and optical images

    NASA Astrophysics Data System (ADS)

    Uss, M.; Vozel, B.; Lukin, V.; Chehdi, K.

    2015-10-01

    This paper investigates the potential accuracy achievable for optical to radar image registration by area-based approach. The analysis is carried out mainly based on the Cramér-Rao Lower Bound (CRLB) on translation estimation accuracy previously proposed by the authors and called CRLBfBm. This bound is now modified to take into account radar image speckle noise properties: spatial correlation and signal-dependency. The newly derived theoretical bound is fed with noise and texture parameters estimated for the co-registered pair of optical Landsat 8 and radar SIR-C images. It is found that difficulty of optical to radar image registration stems more from speckle noise influence than from dissimilarity of the considered kinds of images. At finer scales (and higher speckle noise level), probability of finding control fragments (CF) suitable for registration is low (1% or less) but overall number of such fragments is high thanks to image size. Conversely, at the coarse scale, where speckle noise level is reduced, probability of finding CFs suitable for registration can be as high as 40%, but overall number of such CFs is lower. Thus, the study confirms and supports area-based multiresolution approach for optical to radar registration where coarse scales are used for fast registration "lock" and finer scales for reaching higher registration accuracy. The CRLBfBm is found inaccurate for the main scale due to intensive speckle noise influence. For other scales, the validity of the CRLBfBm bound is confirmed by calculating statistical efficiency of area-based registration method based on normalized correlation coefficient (NCC) measure that takes high values of about 25%.

  1. Unnecessary Chemicals

    ERIC Educational Resources Information Center

    Johnson, Anita

    1978-01-01

    Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

  2. Chemical geodynamics

    NASA Astrophysics Data System (ADS)

    Zindler, A.; Hart, S.

    Consideration is given to the following three principal boundary conditions relating to the nature and development of chemical structure in the earth's mantle: (1) inferred scale lengths for mantle chemical heterogeneities, (2) interrelationships of the various isotopic tracers, and (3) the bulk composition of the earth. These boundary conditions are integrated with geophysical constraints in order to evaluate models for the development of the physical and chemical structure of the mantle. Data indicate that: (1) km-size heterogeneities can survive diffusive equilibrium for billions of years; (2) the mantle is chemically heterogeneous on both very small and very large scales; (3) isotopic heterogeneities in the mantle require the existence of four 'end-member' components (DMM, HIMU, EM I, and EM II) and are consistent with the existence of at least two additional components (BSE, PREMA); and (4) primitive undepleted mantle can made up no more than about 55 percent of the total mantle.

  3. Bayesian reclassification statistics for assessing improvements in diagnostic accuracy.

    PubMed

    Huang, Zhipeng; Li, Jialiang; Cheng, Ching-Yu; Cheung, Carol; Wong, Tien-Yin

    2016-07-10

    We propose a Bayesian approach to the estimation of the net reclassification improvement (NRI) and three versions of the integrated discrimination improvement (IDI) under the logistic regression model. Both NRI and IDI were proposed as numerical characterizations of accuracy improvement for diagnostic tests and were shown to retain certain practical advantage over analysis based on ROC curves and offer complementary information to the changes in area under the curve. Our development is a new contribution towards Bayesian solution for the estimation of NRI and IDI, which eases computational burden and increases flexibility. Our simulation results indicate that Bayesian estimation enjoys satisfactory performance comparable with frequentist estimation and achieves point estimation and credible interval construction simultaneously. We adopt the methodology to analyze a real data from the Singapore Malay Eye Study. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26875442

  4. High accuracy LADAR scene projector calibration sensor development

    NASA Astrophysics Data System (ADS)

    Kim, Hajin J.; Cornell, Michael C.; Naumann, Charles B.; Bowden, Mark H.

    2008-04-01

    A sensor system for the characterization of infrared laser radar scene projectors has been developed. Available sensor systems do not provide sufficient range resolution to evaluate the high precision LADAR projector systems developed by the U.S. Army Research, Development and Engineering Command (RDECOM) Aviation and Missile Research, Development and Engineering Center (AMRDEC). With timing precision capability to a fraction of a nanosecond, it can confirm the accuracy of simulated return pulses from a nominal range of up to 6.5 km to a resolution of 4cm. Increased range can be achieved through firmware reconfiguration. Two independent amplitude triggers measure both rise and fall time providing a judgment of pulse shape and allowing estimation of the contained energy. Each return channel can measure up to 32 returns per trigger characterizing each return pulse independently. Currently efforts include extending the capability to 8 channels. This paper outlines the development, testing, capabilities and limitations of this new sensor system.

  5. Spatial augmented reality based high accuracy human face projection

    NASA Astrophysics Data System (ADS)

    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.

  6. Chemical sensors

    DOEpatents

    Lowell, Jr., James R.; Edlund, David J.; Friesen, Dwayne T.; Rayfield, George W.

    1992-01-01

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material.

  7. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1992-06-09

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material. 12 figs.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Method of questioning and the accuracy of eyewitness testimony.

    PubMed

    Venter, A; Louw, D A

    2005-03-01

    System variables are integrally part of factors that can be controlled by the legal system to enhance the accuracy of testimony by eyewitnesses. Apart from examining the relationship between questioning as system variable and the accuracy of testimony, the present study furthermore explores the relationship between type of questioning and certain biographical variables (occupation, age, gender and race). To achieve the aim of the study, 412 respondents consisting of 11 to 14-year-olds, university students, the public and Police College students participated and were exposed to open-ended or closed-ended questions. It was found that the participants who responded to the closed-ended questions were significantly more accurate than those who answered the open-ended questions. All the biographical groups, except the public, were more accurate in responding to the closed-ended questions. The scholars obtained the lowest scores (although not always significant) for both the open-ended and closed-ended questions. With respect to age the 18 to 25-year-olds obtained significantly higher scores than the other groups for the closed-ended questions. Whites performed significantly better than blacks in response to the open-ended and closed-ended questions. PMID:15887614

  10. Optimal diving maneuver strategy considering guidance accuracy for hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Zhu, Jianwen; Liu, Luhua; Tang, Guojian; Bao, Weimin

    2014-11-01

    An optimal maneuver strategy considering terminal guidance accuracy for hypersonic vehicle in dive phase is investigated in this paper. First, it derives the complete three-dimensional nonlinear coupled motion equation without any approximations based on diving relative motion relationship directly, and converts it into linear decoupled state space equation with the same relative degree by feedback linearization. Second, the diving guidance law is designed based on the decoupled equation to meet the terminal impact point and falling angle constraints. In order to further improve the interception capability, it constructs maneuver control model through adding maneuver control item to the guidance law. Then, an integrated performance index consisting of maximum line-of-sight angle rate and minimum energy consumption is designed, and optimal control is employed to obtain optimal maneuver strategy when the encounter time is determined and undetermined, respectively. Furthermore, the performance index and suboptimal strategy are reconstructed to deal with the control capability constraint and the serous influence on terminal guidance accuracy caused by maneuvering flight. Finally, the approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed strategy can achieve high precision guidance and effective maneuver at the same time, and the indices are also optimized.

  11. Evaluation of DEM generation accuracy from UAS imagery

    NASA Astrophysics Data System (ADS)

    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. Generalized and Heuristic-Free Feature Construction for Improved Accuracy

    PubMed Central

    Fan, Wei; Zhong, Erheng; Peng, Jing; Verscheure, Olivier; Zhang, Kun; Ren, Jiangtao; Yan, Rong; Yang, Qiang

    2010-01-01

    State-of-the-art learning algorithms accept data in feature vector format as input. Examples belonging to different classes may not always be easy to separate in the original feature space. One may ask: can transformation of existing features into new space reveal significant discriminative information not obvious in the original space? Since there can be infinite number of ways to extend features, it is impractical to first enumerate and then perform feature selection. Second, evaluation of discriminative power on the complete dataset is not always optimal. This is because features highly discriminative on subset of examples may not necessarily be significant when evaluated on the entire dataset. Third, feature construction ought to be automated and general, such that, it doesn't require domain knowledge and its improved accuracy maintains over a large number of classification algorithms. In this paper, we propose a framework to address these problems through the following steps: (1) divide-conquer to avoid exhaustive enumeration; (2) local feature construction and evaluation within subspaces of examples where local error is still high and constructed features thus far still do not predict well; (3) weighting rules based search that is domain knowledge free and has provable performance guarantee. Empirical studies indicate that significant improvement (as much as 9% in accuracy and 28% in AUC) is achieved using the newly constructed features over a variety of inductive learners evaluated against a number of balanced, skewed and high-dimensional datasets. Software and datasets are available from the authors. PMID:21544257

  13. Does DFT-SAPT method provide spectroscopic accuracy?

    SciTech Connect

    Shirkov, Leonid; Makarewicz, Jan

    2015-02-14

    Ground state potential energy curves for homonuclear and heteronuclear dimers consisting of noble gas atoms from He to Kr were calculated within the symmetry adapted perturbation theory based on the density functional theory (DFT-SAPT). These potentials together with spectroscopic data derived from them were compared to previous high-precision coupled cluster with singles and doubles including the connected triples theory calculations (or better if available) as well as to experimental data used as the benchmark. The impact of midbond functions on DFT-SAPT results was tested to study the convergence of the interaction energies. It was shown that, for most of the complexes, DFT-SAPT potential calculated at the complete basis set (CBS) limit is lower than the corresponding benchmark potential in the region near its minimum and hence, spectroscopic accuracy cannot be achieved. The influence of the residual term δ(HF) on the interaction energy was also studied. As a result, we have found that this term improves the agreement with the benchmark in the repulsive region for the dimers considered, but leads to even larger overestimation of potential depth D{sub e}. Although the standard hybrid exchange-correlation (xc) functionals with asymptotic correction within the second order DFT-SAPT do not provide the spectroscopic accuracy at the CBS limit, it is possible to adjust empirically basis sets yielding highly accurate results.

  14. Evaluation of the dimensional accuracy in single point incremental forming

    NASA Astrophysics Data System (ADS)

    Araújo, R.; Silva, M. B.; Montanari, L.; Teixeira, P.; Reis, A.; Martins, P. A. F.

    2013-12-01

    Incremental Sheet Forming (ISF) is a forming process widely used to obtain small batches or prototypes. By improving forming strategies, the process can be used in a wide range of applications. However, this technology still presents some drawbacks. The dimensional accuracy between the 3D CAD model and the final product is one of the key challenges for this technique. The springback phenomenon during the incremental forming process is an important reason for the lack of accuracy. In order to study the mechanism of this phenomenon, the geometry of the sheet metal was measured in two different stages of the conventional production chain. First, the geometry of the sheet metal part was acquired after the forming stage, without be released from the blank holder. Then, the final geometry was achieved after the cutting process from the original sheet. A 3D scanning system was used to measure and inspect the springback phenomenon of each step. A reverse method is proposed to design the new tool path for compensation of the springback.

  15. On the Accuracy Potential in Underwater/Multimedia Photogrammetry

    PubMed Central

    Maas, Hans-Gerd

    2015-01-01

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

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

    PubMed

    Maas, Hans-Gerd

    2015-01-01

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

  17. Leica Dmc III Calibration and Geometric Sensor Accuracy

    NASA Astrophysics Data System (ADS)

    Mueller, C.; Neumann, K.

    2016-03-01

    As an evolution of the successful DMC II digital camera series, Leica Geosystems has introduced the Leica DMC III digital aerial camera using, for the first time in the industry, a large-format CMOS sensor as a panchromatic high-resolution camera head. This paper describes the Leica DMC III calibration and its quality assurance and quality control (QA/QC) procedures. It will explain how calibration was implemented within the production process for the Leica DMC III camera. Based on many years of experience with the DMC and DMC II camera series, it is know that the sensor flatness has a huge influence on the final achievable results. The Leica DMC III panchromatic CMOS sensor with its 100.3mm x 56.9mm size shows remaining errors in a range of 0.1 to 0.2μm for the root mean square and shows maximum values not higher that 1.0μm. The Leica DMC III is calibrated based on a 5cm Ground Sample Distance (GSD) grid pattern flight and evaluated with three different flying heights at 5cm, 8cm and 11cm GSD. The geometric QA/QC has been performed using the calibration field area, as well as using an independent test field. The geometric performance and accuracy is unique and gives ground accuracies far better than the flown GSD.

  18. Infrared ear thermometers--parameters influencing their reading and accuracy.

    PubMed

    Pusnik, Igor; Drnovsek, Janko

    2005-12-01

    Infrared ear thermometers (IRETs) are extensively used for measuring the temperature of a human body. For accurate measurements with IRETs they have to be calibrated regularly with an appropriate and traceable calibration system. Such systems are neither widely available nor are there many competent (accredited) laboratories which can provide traceability for IRETs. This paper describes some important influential parameters in the calibration and use of IRETs, which were observed during the extensive research on IRETs and have not been reported in the literature yet. IRET readings, and consequently also their most important metrological characteristics, accuracy and uncertainty of measurement, depend on these influential parameters. According to our findings, we would like to warn users of medical radiation thermometers, not only IRETs but also forehead thermometers and infrared temperature scanning systems, that they should be extremely careful in selection, maintenance and use of medical radiation thermometers. Measurement accuracy, as it is required by several technical standards, is hard to achieve with the majority of currently available medical radiation thermometers. PMID:16311454

  19. SHIFTX2: significantly improved protein chemical shift prediction.

    PubMed

    Han, Beomsoo; Liu, Yifeng; Ginzinger, Simon W; Wishart, David S

    2011-05-01

    A new computer program, called SHIFTX2, is described which is capable of rapidly and accurately calculating diamagnetic (1)H, (13)C and (15)N chemical shifts from protein coordinate data. Compared to its predecessor (SHIFTX) and to other existing protein chemical shift prediction programs, SHIFTX2 is substantially more accurate (up to 26% better by correlation coefficient with an RMS error that is up to 3.3× smaller) than the next best performing program. It also provides significantly more coverage (up to 10% more), is significantly faster (up to 8.5×) and capable of calculating a wider variety of backbone and side chain chemical shifts (up to 6×) than many other shift predictors. In particular, SHIFTX2 is able to attain correlation coefficients between experimentally observed and predicted backbone chemical shifts of 0.9800 ((15)N), 0.9959 ((13)Cα), 0.9992 ((13)Cβ), 0.9676 ((13)C'), 0.9714 ((1)HN), 0.9744 ((1)Hα) and RMS errors of 1.1169, 0.4412, 0.5163, 0.5330, 0.1711, and 0.1231 ppm, respectively. The correlation between SHIFTX2's predicted and observed side chain chemical shifts is 0.9787 ((13)C) and 0.9482 ((1)H) with RMS errors of 0.9754 and 0.1723 ppm, respectively. SHIFTX2 is able to achieve such a high level of accuracy by using a large, high quality database of training proteins (>190), by utilizing advanced machine learning techniques, by incorporating many more features (χ(2) and χ(3) angles, solvent accessibility, H-bond geometry, pH, temperature), and by combining sequence-based with structure-based chemical shift prediction techniques. With this substantial improvement in accuracy we believe that SHIFTX2 will open the door to many long-anticipated applications of chemical shift prediction to protein structure determination, refinement and validation. SHIFTX2 is available both as a standalone program and as a web server ( http://www.shiftx2.ca ). PMID:21448735

  20. Positional Accuracy Assessment of Googleearth in Riyadh

    NASA Astrophysics Data System (ADS)

    Farah, Ashraf; Algarni, Dafer

    2014-06-01

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

  1. High Accuracy Fuel Flowmeter, Phase 1

    NASA Technical Reports Server (NTRS)

    Mayer, C.; Rose, L.; Chan, A.; Chin, B.; Gregory, W.

    1983-01-01

    Technology related to aircraft fuel mass - flowmeters was reviewed to determine what flowmeter types could provide 0.25%-of-point accuracy over a 50 to one range in flowrates. Three types were selected and were further analyzed to determine what problem areas prevented them from meeting the high accuracy requirement, and what the further development needs were for each. A dual-turbine volumetric flowmeter with densi-viscometer and microprocessor compensation was selected for its relative simplicity and fast response time. An angular momentum type with a motor-driven, spring-restrained turbine and viscosity shroud was selected for its direct mass-flow output. This concept also employed a turbine for fast response and a microcomputer for accurate viscosity compensation. The third concept employed a vortex precession volumetric flowmeter and was selected for its unobtrusive design. Like the turbine flowmeter, it uses a densi-viscometer and microprocessor for density correction and accurate viscosity compensation.

  2. Accuracy control in Monte Carlo radiative calculations

    NASA Technical Reports Server (NTRS)

    Almazan, P. Planas

    1993-01-01

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

  3. Do saccharide doped PAGAT dosimeters increase accuracy?

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  4. Accuracy of forecasts in strategic intelligence

    PubMed Central

    Mandel, David R.; Barnes, Alan

    2014-01-01

    The accuracy of 1,514 strategic intelligence forecasts abstracted from intelligence reports was assessed. The results show that both discrimination and calibration of forecasts was very good. Discrimination was better for senior (versus junior) analysts and for easier (versus harder) forecasts. Miscalibration was mainly due to underconfidence such that analysts assigned more uncertainty than needed given their high level of discrimination. Underconfidence was more pronounced for harder (versus easier) forecasts and for forecasts deemed more (versus less) important for policy decision making. Despite the observed underconfidence, there was a paucity of forecasts in the least informative 0.4–0.6 probability range. Recalibrating the forecasts substantially reduced underconfidence. The findings offer cause for tempered optimism about the accuracy of strategic intelligence forecasts and indicate that intelligence producers aim to promote informativeness while avoiding overstatement. PMID:25024176

  5. Accuracy of NHANES periodontal examination protocols.

    PubMed

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

    2010-11-01

    This study evaluates the accuracy of periodontitis prevalence determined by the National Health and Nutrition Examination Survey (NHANES) partial-mouth periodontal examination protocols. True periodontitis prevalence was determined in a new convenience sample of 454 adults ≥ 35 years old, by a full-mouth "gold standard" periodontal examination. This actual prevalence was compared with prevalence resulting from analysis of the data according to the protocols of NHANES III and NHANES 2001-2004, respectively. Both NHANES protocols substantially underestimated the prevalence of periodontitis by 50% or more, depending on the periodontitis case definition used, and thus performed below threshold levels for moderate-to-high levels of validity for surveillance. Adding measurements from lingual or interproximal sites to the NHANES 2001-2004 protocol did not improve the accuracy sufficiently to reach acceptable sensitivity thresholds. These findings suggest that NHANES protocols produce high levels of misclassification of periodontitis cases and thus have low validity for surveillance and research. PMID:20858782

  6. Improvement in Rayleigh Scattering Measurement Accuracy

    NASA Technical Reports Server (NTRS)

    Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2012-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous velocity, density, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of an acousto-optic frequency shifting device to improve measurement accuracy in Rayleigh scattering experiments at the NASA Glenn Research Center. The frequency shifting device is used as a means of shifting the incident or reference laser frequency by 1100 MHz to avoid overlap of the Rayleigh and reference signal peaks in the interference pattern used to obtain the velocity, density, and temperature measurements, and also to calibrate the free spectral range of the Fabry-Perot etalon. The measurement accuracy improvement is evaluated by comparison of Rayleigh scattering measurements acquired with and without shifting of the reference signal frequency in a 10 mm diameter subsonic nozzle flow.

  7. Marginal accuracy of temporary composite crowns.

    PubMed

    Tjan, A H; Tjan, A H; Grant, B E

    1987-10-01

    An in vitro study was conducted to quantitatively compare the marginal adaptation of temporary crowns made from Protemp material with those made from Scutan, Provisional, and Trim materials. A direct technique was used to make temporary restorations on prepared teeth with an impression as a matrix. Protem, Trim, and Provisional materials produced temporary crowns of comparable accuracy. Crowns made from Scutan material had open margins. PMID:2959770

  8. Arizona Vegetation Resource Inventory (AVRI) accuracy assessment

    USGS Publications Warehouse

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

    1982-01-01

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

  9. Measurement Accuracy Limitation Analysis on Synchrophasors

    SciTech Connect

    Zhao, Jiecheng; Zhan, Lingwei; Liu, Yilu; Qi, Hairong; Gracia, Jose R; Ewing, Paul D

    2015-01-01

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

  10. Gravitational model effects on ICBM accuracy

    NASA Astrophysics Data System (ADS)

    Ford, C. T.

    This paper describes methods used to assess the contribution of ICBM gravitational model errors to targeting accuracy. The evolution of gravitational model complexity, in both format and data base development, is summarized. Error analysis methods associated with six identified error sources are presented: geodetic coordinate errors; spherical harmonic potential function errors of commission and omission; and surface gravity anomaly errors of reduction, representation, and omission.

  11. Accuracy of pointing a binaural listening array.

    PubMed

    Letowski, T R; Ricard, G L; Kalb, J T; Mermagen, T J; Amrein, K M

    1997-12-01

    We measured the accuracy with which sounds heard over a binaural, end-fire array could be located when the angular separation of the array's two arms was varied. Each individual arm contained nine cardioid electret microphones, the responses of which were combined to produce a unidirectional, band-limited pattern of sensitivity. We assessed the desirable angular separation of these arms by measuring the accuracy with which listeners could point to the source of a target sound presented against high-level background noise. We employed array separations of 30 degrees, 45 degrees, and 60 degrees, and signal-to-noise ratios of +5, -5, and -15 dB. Pointing accuracy was best for a separation of 60 degrees; this performance was indistinguishable from pointing during unaided listening conditions. In addition, the processing of the array was modeled to depict the information that was available for localization. The model indicates that highly directional binaural arrays can be expected to support accurate localization of sources of sound only near the axis of the array. Wider enhanced listening angles may be possible if the forward coverage of the sensor system is made less directional and more similar to that of human listeners. PMID:9473975

  12. Accuracy test procedure for image evaluation techniques.

    PubMed

    Jones, R A

    1968-01-01

    A procedure has been developed to determine the accuracy of image evaluation techniques. In the procedure, a target having orthogonal test arrays is photographed with a high quality optical system. During the exposure, the target is subjected to horizontal linear image motion. The modulation transfer functions of the images in the horizontal and vertical directions are obtained using the evaluation technique. Since all other degradations are symmetrical, the quotient of the two modulation transfer functions represents the modulation transfer function of the experimentally induced linear image motion. In an accurate experiment, any discrepancy between the experimental determination and the true value is due to inaccuracy in the image evaluation technique. The procedure was used to test the Perkin-Elmer automated edge gradient analysis technique over the spatial frequency range of 0-200 c/m. This experiment demonstrated that the edge gradient technique is accurate over this region and that the testing procedure can be controlled with the desired accuracy. Similarly, the test procedure can be used to determine the accuracy of other image evaluation techniques. PMID:20062421

  13. Determination of GPS orbits to submeter accuracy

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  14. A Family of Rater Accuracy Models.

    PubMed

    Wolfe, Edward W; Jiao, Hong; Song, Tian

    2015-01-01

    Engelhard (1996) proposed a rater accuracy model (RAM) as a means of evaluating rater accuracy in rating data, but very little research exists to determine the efficacy of that model. The RAM requires a transformation of the raw score data to accuracy measures by comparing rater-assigned scores to true scores. Indices computed based on raw scores also exist for measuring rater effects, but these indices ignore deviations of rater-assigned scores from true scores. This paper demonstrates the efficacy of two versions of the RAM (based on dichotomized and polytomized deviations of rater-assigned scores from true scores) to two versions of raw score rater effect models (i.e., a Rasch partial credit model, PCM, and a Rasch rating scale model, RSM). Simulated data are used to demonstrate the efficacy with which these four models detect and differentiate three rater effects: severity, centrality, and inaccuracy. Results indicate that the RAMs are able to detect, but not differentiate, rater severity and inaccuracy, but not rater centrality. The PCM and RSM, on the other hand, are able to both detect and differentiate all three of these rater effects. However, the RSM and PCM do not take into account true scores and may, therefore, be misleading when pervasive trends exist in the rater-assigned data. PMID:26075664

  15. Speed/accuracy tradeoff in force perception.

    PubMed

    Rank, Markus; Di Luca, Massimiliano

    2015-06-01

    There is a well-known tradeoff between speed and accuracy in judgments made under uncertainty. Diffusion models have been proposed to capture the increase in response time for more uncertain decisions and the change in performance due to a prioritization of speed or accuracy in the responses. Experimental paradigms have been confined to the visual modality and model analysis have mostly used quantile-probability (QP) plots--response probability as a function of quantized RTs. Here, we extend diffusion modeling to haptics and test a novel type of analysis for judging model fitting. Participants classified force stimuli applied to the hand as "high" or "low." Data in QP plots indicate that the diffusion model captures well the overall pattern of responses in conditions where either speed or accuracy has been prioritized. To further the analysis, we compute just noticeable difference (JND) values separately for responses delivered with different RTs--we define these plots as JND quantile. The pattern of results evidences that slower responses lead to better force discrimination up to a plateau that is unaffected by prioritization instructions. Instead, the diffusion model predicts two well-separated plateaus depending on the condition. We propose that analyzing the relation between JNDs and response time should be considered in the evaluation of the diffusion model beyond the haptic modality, thus including vision. PMID:25867512

  16. Ground Truth Accuracy Tests of GPS Seismology

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  17. Piezoresistive position microsensors with ppm-accuracy

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  18. Speed versus accuracy in collective decision making.

    PubMed Central

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

    2003-01-01

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

  19. On the Accuracy of Genomic Selection

    PubMed Central

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

    2016-01-01

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

  20. 100% Classification Accuracy Considered Harmful: The Normalized Information Transfer Factor Explains the Accuracy Paradox

    PubMed Central

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

    2014-01-01

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

  1. 100% classification accuracy considered harmful: the normalized information transfer factor explains the accuracy paradox.

    PubMed

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

    2014-01-01

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

  2. Lags in Minority Achievement Defy Traditional Explanations. The Achievement Gap.

    ERIC Educational Resources Information Center

    Viadero, Debra; Johnston, Robert C.

    2000-01-01

    This second in a four-part series on why academic achievement gaps exist notes that standard explanations for why minority students trail behind non-Hispanic whites are not good enough, suggesting that no single explanation for the gap exists, but instead a multitude of factors are influential. Poverty, though not the single most important cause,…

  3. Central Iowa Low Achiever Mathematics Project - Low Achiever Motivational Project.

    ERIC Educational Resources Information Center

    Zimmerman, Joseph T.

    The materials in this booklet are designed especially for the low achieving student in mathematics. Containing some materials from a course in general mathematics, the booklet is intended to be used in conjunction with conventional textbook materials and is designed to serve as a source of new ideas for teachers and to relieve the teacher of much…

  4. Chemical sensors

    SciTech Connect

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section.

  5. Intelligence: The Speed and Accuracy Tradeoff in High Aptitude Individuals.

    ERIC Educational Resources Information Center

    Lajoie, Suzanne P.; Shore, Bruce M.

    1986-01-01

    The relative contributions of mental speed and accuracy to Primary Mental Ability (PMA) IQ prediction were studied in 52 high ability grade 10 students. Both speed and accuracy independently predicted IQ, but not speed over and above accuracy. Accuracy was demonstrated to be universally advantageous in IQ performance, but speed varied according to…

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

    PubMed

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

    2011-09-01

    A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties. PMID:21550259

  7. Accuracy Assessment of Underwater Photogrammetric Three Dimensional Modelling for Coral Reefs

    NASA Astrophysics Data System (ADS)

    Guo, T.; Capra, A.; Troyer, M.; Gruen, A.; Brooks, A. J.; Hench, J. L.; Schmitt, R. J.; Holbrook, S. J.; Dubbini, M.

    2016-06-01

    Recent advances in automation of photogrammetric 3D modelling software packages have stimulated interest in reconstructing highly accurate 3D object geometry in unconventional environments such as underwater utilizing simple and low-cost camera systems. The accuracy of underwater 3D modelling is affected by more parameters than in single media cases. This study is part of a larger project on 3D measurements of temporal change of coral cover in tropical waters. It compares the accuracies of 3D point clouds generated by using images acquired from a system camera mounted in an underwater housing and the popular GoPro cameras respectively. A precisely measured calibration frame was placed in the target scene in order to provide accurate control information and also quantify the errors of the modelling procedure. In addition, several objects (cinder blocks) with various shapes were arranged in the air and underwater and 3D point clouds were generated by automated image matching. These were further used to examine the relative accuracy of the point cloud generation by comparing the point clouds of the individual objects with the objects measured by the system camera in air (the best possible values). Given a working distance of about 1.5 m, the GoPro camera can achieve a relative accuracy of 1.3 mm in air and 2.0 mm in water. The system camera achieved an accuracy of 1.8 mm in water, which meets our requirements for coral measurement in this system.

  8. Experimental studies of high-accuracy RFID localization with channel impairments

    NASA Astrophysics Data System (ADS)

    Pauls, Eric; Zhang, Yimin D.

    2015-05-01

    Radio frequency identification (RFID) systems present an incredibly cost-effective and easy-to-implement solution to close-range localization. One of the important applications of a passive RFID system is to determine the reader position through multilateration based on the estimated distances between the reader and multiple distributed reference tags obtained from, e.g., the received signal strength indicator (RSSI) readings. In practice, the achievable accuracy of passive RFID reader localization suffers from many factors, such as the distorted RSSI reading due to channel impairments in terms of the susceptibility to reader antenna patterns and multipath propagation. Previous studies have shown that the accuracy of passive RFID localization can be significantly improved by properly modeling and compensating for such channel impairments. The objective of this paper is to report experimental study results that validate the effectiveness of such approaches for high-accuracy RFID localization. We also examine a number of practical issues arising in the underlying problem that limit the accuracy of reader-tag distance measurements and, therefore, the estimated reader localization. These issues include the variations in tag radiation characteristics for similar tags, effects of tag orientations, and reader RSS quantization and measurement errors. As such, this paper reveals valuable insights of the issues and solutions toward achieving high-accuracy passive RFID localization.

  9. Factors Governing Surface Form Accuracy In Diamond Machined Components

    NASA Astrophysics Data System (ADS)

    Myler, J. K.; Page, D. A.

    1988-10-01

    Manufacturing methods for diamond machined optical surfaces, for application at infrared wavelengths, require that a new set of criteria must be recognised for the specification of surface form. Appropriate surface form parameters are discussed with particular reference to an XY cartesian geometry CNC machine. Methods for reducing surface form errors in diamond machining are discussed for certain areas such as tool wear, tool centring, and the fixturing of the workpiece. Examples of achievable surface form accuracy are presented. Traditionally, optical surfaces have been produced by use of random polishing techniques using polishing compounds and lapping tools. For lens manufacture, the simplest surface which could be created corresponded to a sphere. The sphere is a natural outcome of a random grinding and polishing process. The measurement of the surface form accuracy would most commonly be performed using a contact test gauge plate, polished to a sphere of known radius of curvature. QA would simply be achieved using a diffuse monochromatic source and looking for residual deviations between the polished surface and the test plate. The specifications governing the manufacture of surfaces using these techniques would call for the accuracy to which the generated surface should match the test plate as defined by a spherical deviations from the required curvature and a non spherical astigmatic error. Consequently, optical design software has tolerancing routines which specifically allow the designer to assess the influence of spherical error and astigmatic error on the optical performance. The creation of general aspheric surfaces is not so straightforward using conventional polishing techniques since the surface profile is non spherical and a good approximation to a power series. For infra red applications (X = 8-12p,m) numerically controlled single point diamond turning is an alternative manufacturing technology capable of creating aspheric profiles as well as

  10. Chemical networks

    NASA Astrophysics Data System (ADS)

    Thi, Wing-Fai

    2015-09-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One on-going research subject is finding new paths to synthesize species either in the gas-phase or on grain surfaces. Specific formation routes for water or carbon monoxide are discussed in more details. 13th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  11. Computer-aided high-accuracy testing of reflective surface with reverse Hartmann test.

    PubMed

    Wang, Daodang; Zhang, Sen; Wu, Rengmao; Huang, Chih Yu; Cheng, Hsiang-Nan; Liang, Rongguang

    2016-08-22

    The deflectometry provides a feasible way for surface testing with a high dynamic range, and the calibration is a key issue in the testing. A computer-aided testing method based on reverse Hartmann test, a fringe-illumination deflectometry, is proposed for high-accuracy testing of reflective surfaces. The virtual "null" testing of surface error is achieved based on ray tracing of the modeled test system. Due to the off-axis configuration in the test system, it places ultra-high requirement on the calibration of system geometry. The system modeling error can introduce significant residual systematic error in the testing results, especially in the cases of convex surface and small working distance. A calibration method based on the computer-aided reverse optimization with iterative ray tracing is proposed for the high-accuracy testing of reflective surface. Both the computer simulation and experiments have been carried out to demonstrate the feasibility of the proposed measurement method, and good measurement accuracy has been achieved. The proposed method can achieve the measurement accuracy comparable to the interferometric method, even with the large system geometry calibration error, providing a feasible way to address the uncertainty on the calibration of system geometry. PMID:27557245

  12. PHAT: PHoto-z Accuracy Testing

    NASA Astrophysics Data System (ADS)

    Hildebrandt, H.; Arnouts, S.; Capak, P.; Moustakas, L. A.; Wolf, C.; Abdalla, F. B.; Assef, R. J.; Banerji, M.; Benítez, N.; Brammer, G. B.; Budavári, 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.

    2010-11-01

    Context. Photometric redshifts (photo-z's) have become an essential tool in extragalactic astronomy. Many current and upcoming observing programmes require great accuracy of photo-z's to reach their scientific goals. Aims: Here we introduce PHAT, the PHoto-z Accuracy Testing programme, an international initiative to test and compare different methods of photo-z estimation. Methods: 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 including 18-band photometry and ~2000 spectroscopic redshifts. Results: The accuracy of the different methods is expressed and ranked by the global photo-z bias, scatter, and outlier rates. While most methods agree very well on PHAT0 there are differences in the handling of the Lyman-α forest for higher redshifts. Furthermore, different methods 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. The accuracy of the other methods is unaffected or suffers when IRAC data are included. Remaining biases and systematic effects can be explained by shortcomings in the different template sets (especially in the mid-IR) and the use of priors on the one hand and an insufficient training set on the other hand. Some strategies to overcome these problems are identified by comparing the methods in detail. Scatters of 4-8% in Δz/(1+z) were obtained, consistent with other studies. However, somewhat larger outlier rates (>7.5% with Δz/(1+z)>0.15; >4.5% after cleaning) are found for all codes that can only partly be explained by AGN or issues in the photometry or the spec-z catalogue. Some outliers were probably missed in comparisons of photo-z's to other, less complete spectroscopic surveys in the past. There is a general trend that empirical codes produce

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

    PubMed

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

    2016-01-01

    Forensic photographs not only need to be unaltered and authentic and capture context-relevant images, along with certain minimum requirements for image sharpness and information density, but color accuracy also plays an important role, for instance, in the assessment of injuries or taphonomic stages, or in the identification and evaluation of traces from photos. The perception of color not only varies subjectively from person to person, but as a discrete property of an image, color in digital photos is also to a considerable extent influenced by technical factors such as lighting, acquisition settings, camera, and output medium (print, monitor). For these reasons, consistent color accuracy has so far been limited in digital photography. Because images usually contain a wealth of color information, especially for complex or composite colors or shades of color, and the wavelength-dependent sensitivity to factors such as light and shadow may vary between cameras, the usefulness of issuing general recommendations for camera capture settings is limited. Our results indicate that true image colors can best and most realistically be captured with the SpyderCheckr technical calibration tool for digital cameras tested in this study. Apart from aspects such as the simplicity and quickness of the calibration procedure, a further advantage of the tool is that the results are independent of the camera used and can also be used for the color management of output devices such as monitors and printers. The SpyderCheckr color-code patches allow true colors to be captured more realistically than with a manual white balance tool or an automatic flash. We therefore recommend that the use of a color management tool should be considered for the acquisition of all images that demand high true color accuracy (in particular in the setting of injury documentation). PMID:27386623

  14. Accuracy Assessment of Altimeter Derived Geostrophic Velocities

    NASA Astrophysics Data System (ADS)

    Leben, R. R.; Powell, B. S.; Born, G. H.; Guinasso, N. L.

    2002-12-01

    Along track sea surface height anomaly gradients are proportional to cross track geostrophic velocity anomalies allowing satellite altimetry to provide much needed satellite observations of changes in the geostrophic component of surface ocean currents. Often, surface height gradients are computed from altimeter data archives that have been corrected to give the most accurate absolute sea level, a practice that may unnecessarily increase the error in the cross track velocity anomalies and thereby require excessive smoothing to mitigate noise. Because differentiation along track acts as a high-pass filter, many of the path length corrections applied to altimeter data for absolute height accuracy are unnecessary for the corresponding gradient calculations. We report on a study to investigate appropriate altimetric corrections and processing techniques for improving geostrophic velocity accuracy. Accuracy is assessed by comparing cross track current measurements from two moorings placed along the descending TOPEX/POSEIDON ground track number 52 in the Gulf of Mexico to the corresponding altimeter velocity estimates. The buoys are deployed and maintained by the Texas Automated Buoy System (TABS) under Interagency Contracts with Texas A&M University. The buoys telemeter observations in near real-time via satellite to the TABS station located at the Geochemical and Environmental Research Group (GERG) at Texas A&M. Buoy M is located in shelf waters of 57 m depth with a second, Buoy N, 38 km away on the shelf break at 105 m depth. Buoy N has been operational since the beginning of 2002 and has a current meter at 2m depth providing in situ measurements of surface velocities coincident with Jason and TOPEX/POSEIDON altimeter over flights. This allows one of the first detailed comparisons of shallow water near surface current meter time series to coincident altimetry.

  15. Accuracy of velocities from repeated GPS measurements

    NASA Astrophysics Data System (ADS)

    Akarsu, V.; Sanli, D. U.; Arslan, E.

    2015-04-01

    Today repeated GPS measurements are still in use, because we cannot always employ GPS permanent stations due to a variety of limitations. One area of study that uses velocities/deformation rates from repeated GPS measurements is the monitoring of crustal motion. This paper discusses the quality of the velocities derived using repeated GPS measurements for the aim of monitoring crustal motion. From a global network of International GNSS Service (IGS) stations, we processed GPS measurements repeated monthly and annually spanning nearly 15 years and estimated GPS velocities for GPS baseline components latitude, longitude and ellipsoidal height. We used web-based GIPSY for the processing. Assuming true deformation rates can only be determined from the solutions of 24 h observation sessions, we evaluated the accuracy of the deformation rates from 8 and 12 h sessions. We used statistical hypothesis testing to assess the velocities derived from short observation sessions. In addition, as an alternative control method we checked the accuracy of GPS solutions from short observation sessions against those of 24 h sessions referring to statistical criteria that measure the accuracy of regression models. Results indicate that the velocities of the vertical component are completely affected when repeated GPS measurements are used. The results also reveal that only about 30% of the 8 h solutions and about 40% of 12 h solutions for the horizontal coordinates are acceptable for velocity estimation. The situation is much worse for the vertical component in which none of the solutions from campaign measurements are acceptable for obtaining reliable deformation rates.

  16. Accuracy of abdominal auscultation for bowel obstruction

    PubMed Central

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

    2015-01-01

    AIM: To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction. METHODS: Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann® Electronic Stethoscope. The recordings were processed to yield 25-s sound sequences in random order on PCs. Observers, recruited from doctors within the department, classified the sound sequences as either normal or pathological. The reference tests for bowel obstruction were intraoperative and endoscopic findings and clinical follow up. Sensitivity and specificity were calculated for each observer and compared between junior and senior doctors. Interobserver variation was measured using the Kappa statistic. RESULTS: Bowel sound sequences from 98 patients were assessed by 53 (33 junior and 20 senior) doctors. Laparotomy was performed in 47 patients, 35 of whom had bowel obstruction. Two patients underwent colorectal stenting due to large bowel obstruction. The median sensitivity and specificity was 0.42 (range: 0.19-0.64) and 0.78 (range: 0.35-0.98), respectively. There was no significant difference in accuracy between junior and senior doctors. The median frequency with which doctors classified bowel sounds as abnormal did not differ significantly between patients with and without bowel obstruction (26% vs 23%, P = 0.08). The 53 doctors made up 1378 unique pairs and the median Kappa value was 0.29 (range: -0.15-0.66). CONCLUSION: Accuracy and inter-observer agreement was generally low. Clinical decisions in patients with possible bowel obstruction should not be based on auscultatory assessment of bowel sounds. PMID:26379407

  17. Accuracy requirements. [for monitoring of climate changes

    NASA Technical Reports Server (NTRS)

    Delgenio, Anthony

    1993-01-01

    Satellite and surface measurements, if they are to serve as a climate monitoring system, must be accurate enough to permit detection of changes of climate parameters on decadal time scales. The accuracy requirements are difficult to define a priori since they depend on unknown future changes of climate forcings and feedbacks. As a framework for evaluation of candidate Climsat instruments and orbits, we estimate the accuracies that would be needed to measure changes expected over two decades based on theoretical considerations including GCM simulations and on observational evidence in cases where data are available for rates of change. One major climate forcing known with reasonable accuracy is that caused by the anthropogenic homogeneously mixed greenhouse gases (CO2, CFC's, CH4 and N2O). Their net forcing since the industrial revolution began is about 2 W/sq m and it is presently increasing at a rate of about 1 W/sq m per 20 years. Thus for a competing forcing or feedback to be important, it needs to be of the order of 0.25 W/sq m or larger on this time scale. The significance of most climate feedbacks depends on their sensitivity to temperature change. Therefore we begin with an estimate of decadal temperature change. Presented are the transient temperature trends simulated by the GISS GCM when subjected to various scenarios of trace gas concentration increases. Scenario B, which represents the most plausible near-term emission rates and includes intermittent forcing by volcanic aerosols, yields a global mean surface air temperature increase Delta Ts = 0.7 degrees C over the time period 1995-2015. This is consistent with the IPCC projection of about 0.3 degrees C/decade global warming (IPCC, 1990). Several of our estimates below are based on this assumed rate of warming.

  18. Improvement of focus accuracy on processed wafer

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  19. A hyperspectral imager for high radiometric accuracy Earth climate studies

    NASA Astrophysics Data System (ADS)

    Espejo, Joey; Drake, Ginger; Heuerman, Karl; Kopp, Greg; Lieber, Alex; Smith, Paul; Vermeer, Bill

    2011-10-01

    We demonstrate a visible and near-infrared prototype pushbroom hyperspectral imager for Earth climate studies that is capable of using direct solar viewing for on-orbit cross calibration and degradation tracking. Direct calibration to solar spectral irradiances allow the Earth-viewing instrument to achieve required climate-driven absolute radiometric accuracies of <0.2% (1σ). A solar calibration requires viewing scenes having radiances 105 higher than typical Earth scenes. To facilitate this calibration, the instrument features an attenuation system that uses an optimized combination of different precision aperture sizes, neutral density filters, and variable integration timing for Earth and solar viewing. The optical system consists of a three-mirror anastigmat telescope and an Offner spectrometer. The as-built system has a 12.2° cross track field of view with 3 arcmin spatial resolution and covers a 350-1050 nm spectral range with 10 nm resolution. A polarization compensated configuration using the Offner in an out of plane alignment is demonstrated as a viable approach to minimizing polarization sensitivity. The mechanical design takes advantage of relaxed tolerances in the optical design by using rigid, non-adjustable diamond-turned tabs for optical mount locating surfaces. We show that this approach achieves the required optical performance. A prototype spaceflight unit is also demonstrated to prove the applicability of these solar cross calibration methods to on-orbit environments. This unit is evaluated for optical performance prior to and after GEVS shake, thermal vacuum, and lifecycle tests.

  20. Stabilized high-accuracy optical tracking system (SHOTS)

    NASA Astrophysics Data System (ADS)

    Ruffatto, Donald; Brown, H. Donald; Pohle, Richard H.; Reiley, Michael F.; Haddock, Delmar D.

    2001-08-01

    This paper describes an 0.75 meter aperture, Stabilized High-accuracy Optical Tracking System (SHOTS), two of which are being developed by Textron Systems Corporation, under contract to the Navy's Space and Naval Warfare Systems Center, San Diego (SPAWAR-SD). The SHOTS design is optimized to meet the requirements of the Navy's Theater Ballistic Missile Defense (TBMD) testing program being conducted at the Kauai Pacific Missile Range Facility (PMRF). The SHOTS utilizes a high-precision, GPS aided inertial navigation unit (INU) coupled with a 3-axis, rate gyro stabilized mount which allows precision pointing to be achieved on either land or sea-based platforms. The SHOTS mount control system architecture, acquisition, tracking and pointing (ATP) functionality and methodology which allows the system to meet the TBMD mission data collection requirements are discussed. High frame rate visible and MWIR sensors are incorporated into the system design to provide the capability of capturing short duration events, e.g., missile-target intercepts. These sensors along with the supporting high speed data acquisition, recording and control subsystems are described. Simulations of the SHOTS imaging performance in TBMD measurement scenarios are presented along with an example of the image improvement being achieved with post-processing image reconstruction algorithms.

  1. High accuracy radiation efficiency measurement techniques

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  2. Accuracy of the river discharge measurement

    NASA Astrophysics Data System (ADS)

    Chung Yang, Han

    2013-04-01

    Discharge values recorded for water conservancy and hydrological analysis is a very important work. Flood control projects, watershed remediation and river environmental planning projects quite need the discharge measurement data. In Taiwan, we have 129 rivers, in accordance with the watershed situation, economic development and other factors, divided into 24 major rivers, 29 minor rivers and 79 ordinary rivers. If each river needs to measure and record these discharge values, it will be enormous work. In addition, the characteristics of Taiwan's rivers contain steep slope, flow rapidly and sediment concentration higher, so it really encounters some difficulties in high flow measurement. When the flood hazards come, to seek a solution for reducing the time, manpower and material resources in river discharge measurement is very important. In this study, the river discharge measurement accuracy is used to determine the tolerance percentage to reduce the number of vertical velocity measurements, thereby reducing the time, manpower and material resources in the river discharge measurement. The velocity data sources used in this study form Yang (1998). Yang (1998) used the Fiber-optic Laser Doppler Velocimetery (FLDV) to obtain different velocity data under different experimental conditions. In this study, we use these data to calculate the mean velocity of each vertical line by three different velocity profile formula (that is, the law of the wall, Chiu's theory, Hu's theory), and then multiplied by each sub-area to obtain the discharge measurement values and compared with the true values (obtained by the direct integration mode) to obtain the accuracy of discharge. The research results show that the discharge measurement values obtained by Chiu's theory are closer to the true value, while the maximum error is the law of the wall. The main reason is that the law of the wall can't describe the maximum velocity occurred in underwater. In addition, the results also show

  3. New analytical algorithm for overlay accuracy

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    The extension of optical lithography to 2Xnm and beyond is often challenged by overlay control. With reduced overlay measurement error budget in the sub-nm range, conventional Total Measurement Uncertainty (TMU) data is no longer sufficient. Also there is no sufficient criterion in overlay accuracy. In recent years, numerous authors have reported new method of the accuracy of the overlay metrology: Through focus and through color. Still quantifying uncertainty in overlay measurement is most difficult work in overlay metrology. According to the ITRS roadmap, total overlay budget is getting tighter than former device node as a design rule shrink on each device node. Conventionally, the total overlay budget is defined as the square root of square sum of the following contributions: the scanner overlay performance, wafer process, metrology and mask registration. All components have been supplying sufficiently performance tool to each device nodes, delivering new scanner, new metrology tools, and new mask e-beam writers. Especially the scanner overlay performance was drastically decreased from 9nm in 8x node to 2.5nm in 3x node. The scanner overlay seems to reach the limitation the overlay performance after 3x nod. The importance of the wafer process overlay as a contribution of total wafer overlay became more important. In fact, the wafer process overlay was decreased by 3nm between DRAM 8x node and DRAM 3x node. We develop an analytical algorithm for overlay accuracy. And a concept of nondestructive method is proposed in this paper. For on product layer we discovered the layer has overlay inaccuracy. Also we use find out source of the overlay error though the new technique. In this paper, authors suggest an analytical algorithm for overlay accuracy. And a concept of non-destructive method is proposed in this paper. For on product layers, we discovered it has overlay inaccuracy. Also we use find out source of the overlay error though the new technique. Furthermore

  4. Evaluating the accuracy of transcribed clinical data.

    PubMed Central

    Wilton, R.; Pennisi, A. J.

    1993-01-01

    This study evaluated the accuracy of data transcribed into a computer-stored record from a handwritten listing of pediatric immunizations. The immunization records of 459 children seen in the UCLA Children's Health Center in March, 1993 were transcribed into a clinical computer system on an ongoing basis. Of these records, 27 (5.9%) were subsequently found to be inaccurate. Reasons for inaccuracy in the transcribed records included incomplete written records, incomplete transcription of written records, and unavailability of immunization records from multiple health-care providers. The utility of a computer-stored clinical record may be adversely affected by unavoidable inaccuracies in transcribed clinical data. PMID:8130478

  5. Potential-Based Achievement Goals

    ERIC Educational Resources Information Center

    Elliot, Andrew; Murayama, Kou; Kobeisy, Ahmed; Lichtenfeld, Stephanie

    2015-01-01

    Background: Self-based achievement goals use one's own intrapersonal trajectory as a standard of evaluation, and this intrapersonal trajectory may be grounded in one's past (past-based goals) or one's future potential (potential-based goals). Potential-based goals have been overlooked in the literature to date. Aims: The primary aim of the present…

  6. The Racial Academic Achievement Gap

    ERIC Educational Resources Information Center

    Green, Toneka M.

    2008-01-01

    Closing the racial academic achievement gap is a problem that must be solved in order for future society to properly function. Minorities including African-American and Latino students' standardized test scores are much lower than white students. By the end of fourth grade, African American, Latino, and poor students of all races are two years…

  7. The Achievement-Assessment Link

    ERIC Educational Resources Information Center

    Wallace, Virginia; Husid, Whitney

    2011-01-01

    The recent recession, school budget cuts, and predictions of school libraries' demise because of technology advances put pressure on school librarians to prove the utility, relevance, and value of school libraries to student learning. While national studies document that school libraries increase student achievement, school librarians must…

  8. Cooperative Learning and Student Achievement.

    ERIC Educational Resources Information Center

    Slavin, Robert E.

    1988-01-01

    Research evidence shows that cooperative learning strategies are not equally effective, though most positively affect self-esteem, intergroup relations, and the ability to work with others. To produce achievement gains, these methods must include both a group goal and individual accountability. Includes 19 references. (MLH)

  9. Curricular Diversity and Academic Achievement.

    ERIC Educational Resources Information Center

    Wilson, Reginald

    1991-01-01

    Educational achievement should be intellectually and philosophically divorced from cultural affirmation, which is merely a byproduct of the inclusion of diverse voices in the search for truth. A model based on the relationship between the valuation of oneself by others and by oneself is presented to explain differential effects of schooling on…

  10. School Readiness and Later Achievement

    ERIC Educational Resources Information Center

    Duncan, Greg J.; Dowsett, Chantelle J.; Claessens, Amy; Magnuson, Katherine; Huston, Aletha C.; Klebanov, Pamela; Pagani, Linda S.; Feinstein, Leon; Engel, Mimi; Brooks-Gunn, Jeanne; Sexton, Holly; Duckworth, Kathryn; Japel, Crista

    2007-01-01

    Using 6 longitudinal data sets, the authors estimate links between three key elements of school readiness--school-entry academic, attention, and socioemotional skills--and later school reading and math achievement. In an effort to isolate the effects of these school-entry skills, the authors ensured that most of their regression models control for…

  11. Teacher Certification and Student Achievement

    ERIC Educational Resources Information Center

    Moss, Patricia Lewis

    2012-01-01

    The purpose of this mixed-method study was to determine if there is a significant difference between the achievement of students who are taught by traditionally prepared teachers and that of students who are taught by alternatively prepared teachers. The study further addressed the perspectives of both groups of teachers regarding selected…

  12. Achieving Safety through Security Management

    NASA Astrophysics Data System (ADS)

    Ridgway, John

    Whilst the achievement of safety objectives may not be possible purely through the administration of an effective Information Security Management System (ISMS), your job as safety manager will be significantly eased if such a system is in place. This paper seeks to illustrate the point by drawing a comparison between two of the prominent standards within the two disciplines of security and safety management.

  13. School Desegregation and Black Achievement.

    ERIC Educational Resources Information Center

    Cook, Thomas; And Others

    Seven papers commissioned by the National Institute of Education in order to clarify the state of recent knowledge about the effects of school desegregation on the academic achievement of black students are contained in this report. The papers, which analyze 19 "core" empirical studies on this topic, include: (1) "What Have Black Children Gained…

  14. Graders' Mathematics Achievement

    ERIC Educational Resources Information Center

    Bond, John B.; Ellis, Arthur K.

    2013-01-01

    The purpose of this experimental study was to investigate the effects of metacognitive reflective assessment instruction on student achievement in mathematics. The study compared the performance of 141 students who practiced reflective assessment strategies with students who did not. A posttest-only control group design was employed, and results…

  15. Epistemological Beliefs and Academic Achievement

    ERIC Educational Resources Information Center

    Arslantas, Halis Adnan

    2016-01-01

    This study aimed to identify the relationship between teacher candidates' epistemological beliefs and academic achievement. The participants of the study were 353 teacher candidates studying their fourth year at the Education Faculty. The Epistemological Belief Scale was used which adapted to Turkish through reliability and validity work by…

  16. Measuring and Recording Student Achievement

    ERIC Educational Resources Information Center

    Universities UK, 2004

    2004-01-01

    The Measuring and Recording Student Achievement Scoping Group was established by Universities UK and the Standing Conference of Principals (SCOP), with the support of the Higher Education Funding Council for England (HEFCE) in October 2003 to review the recommendations from the UK Government White Paper "The Future of Higher Education" relating…

  17. Academic Achievement in Effective Schools

    ERIC Educational Resources Information Center

    Basque, Marc; Bouchamma, Yamina

    2013-01-01

    Purpose: The purpose of this study is to identify predictors of achievement in mathematics in elementary schools in New Brunswick (Canada). Data Collection: Both teachers and school leaders (N = 111) completed a questionnaire on their practices and on school functioning. Findings: Multiple regression analyses revealed that the students'…

  18. Adequacy, Litigation, and Student Achievement

    ERIC Educational Resources Information Center

    Glenn, William

    2008-01-01

    The court system has been an increasingly important forum in the attempts to remedy the persistent achievement gaps in American education. In the past twenty years, school finance adequacy litigation has replaced desegregation as the most widely used legal strategy in these efforts. Despite the widespread use of adequacy litigation, few…

  19. Achieving a sustainable service advantage.

    PubMed

    Coyne, K P

    1993-01-01

    Many managers believe that superior service should play little or no role in competitive strategy; they maintain that service innovations are inherently copiable. However, the author states that this view is too narrow. For a company to achieve a lasting service advantage, it must base a new service on a capability gap that competitors cannot or will not copy. PMID:10123422

  20. Goal Setting to Achieve Results

    ERIC Educational Resources Information Center

    Newman, Rich

    2012-01-01

    Both districts and individual schools have a very clear set of goals and skills for their students to achieve and master. In fact, except in rare cases, districts and schools develop very detailed goals they wish to pursue. In most cases, unfortunately, only the teachers and staff at a particular school or district-level office are aware of the…

  1. Florida's Fit to Achieve Program.

    ERIC Educational Resources Information Center

    Sander, Allan N.; And Others

    1993-01-01

    Describes Florida's "Fit to Achieve," a cardiovascular fitness education program for elementary students. Children are taught responsibility for their own cardiovascular fitness through proper exercise, personal exercise habits, and regular aerobic exercise. The program stresses collaborative effort between physical educators and classroom…

  2. Believing and Achieving. Issue Brief

    ERIC Educational Resources Information Center

    Jerald, Craig D.

    2007-01-01

    This research brief takes a look at the role of teacher efficacy-how teachers' beliefs in their own abilities affect student achievement. The brief examines the influence of perceived efficacy and building teacher confidence (social persuasion, collegiality, and shared decision making). It concludes by asserting that more positive steps must be…

  3. Washington State's Student Achievement Initiative

    ERIC Educational Resources Information Center

    Pettitt, Maureen; Prince, David

    2010-01-01

    This article describes Washington State's Student Achievement Initiative, an accountability system implemented in 2005-06 that measures students' gains in college readiness, college credits earned, and degree or certificate completion. The goal of the initiative is to increase educational attainment by focusing on the critical momentum points…

  4. Achieving Ideological Change within Psychology.

    ERIC Educational Resources Information Center

    Fox, Dennis R.

    Psychologists who are interested in the nature of ideology and the achievement of social change generally focus their primary theoretical and empirical attention on those people outside academia who are trying to change or to prevent change in one political sphere or another. There may be some value in looking at psychology and psychologists as…

  5. Five Standards and Student Achievement.

    ERIC Educational Resources Information Center

    Doherty, R. William; Hilberg, R. Soleste; Pinal, America; Tharp, Roland G.

    2003-01-01

    Two studies examine the influence of the Standards for Effective Pedagogy on student achievement gains. Participants were 15 teachers and 266 students (grades 3 to 5) in a public elementary school serving predominantly low-income Latino English Language Learners (ELLs). Implications for teaching practice and research are discussed. (Author/VWL)

  6. Socioeconomic Determinants of Academic Achievement

    ERIC Educational Resources Information Center

    Tomul, Ekber; Savasci, Havva Sebile

    2012-01-01

    This study aims to investigate the relationship between academic achievement and the socioeconomic characteristics of elementary school 7th grade students in Burdur. The population of the study are 7th grade students who had education at elementary schools in Burdur in the 2007-2008 academic year. Two staged sampling was chosen as suitable for the…

  7. Mobility and the Achievement Gap.

    ERIC Educational Resources Information Center

    Skandera, Hanna; Sousa, Richard

    2002-01-01

    Research indicates that low achievement scores relate significantly to high school mobility rates. One explanation for this relationship is curricular inconsistency. Some suggest that school choice could contribute to a solution by breaking the link between a child's home address and school address, thus allowing students to remain at one school…

  8. The Widening Income Achievement Gap

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2013-01-01

    Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…

  9. School Districts and Student Achievement

    ERIC Educational Resources Information Center

    Chingos, Matthew M.; Whitehurst, Grover J.; Gallaher, Michael R.

    2015-01-01

    School districts are a focus of education reform efforts in the United States, but there is very little existing research about how important they are to student achievement. We fill this gap in the literature using 10 years of student-level, statewide data on fourth- and fifth-grade students in Florida and North Carolina. A variance decomposition…

  10. Can Judges Improve Academic Achievement?

    ERIC Educational Resources Information Center

    Greene, Jay P.; Trivitt, Julie R.

    2008-01-01

    Over the last 3 decades student achievement has remained essentially unchanged in the United States, but not for a lack of spending. Over the same period a myriad of education reforms have been suggested and per-pupil spending has more than doubled. Since the 1990s the education reform attempts have frequently included judicial decisions to revise…

  11. Meeting a Math Achievement Crisis

    ERIC Educational Resources Information Center

    Jennings, Lenora; Likis, Lori

    2005-01-01

    An urban community spotlighted declining mathematics achievement and took some measures, in which the students' performance increased substantially. The Benjamin Banneker Charter Public School in Cambridge, Massachusetts, engaged the entire community and launched the campaign called "Math Everywhere", which changed Benjamin Banneker's culture as…

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

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

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

  13. Accuracy analysis of the space shuttle solid rocket motor profile measuring device

    NASA Technical Reports Server (NTRS)

    Estler, W. Tyler

    1989-01-01

    The Profile Measuring Device (PMD) was developed at the George C. Marshall Space Flight Center following the loss of the Space Shuttle Challenger. It is a rotating gauge used to measure the absolute diameters of mating features of redesigned Solid Rocket Motor field joints. Diameter tolerance of these features are typically + or - 0.005 inches and it is required that the PMD absolute measurement uncertainty be within this tolerance. In this analysis, the absolute accuracy of these measurements were found to be + or - 0.00375 inches, worst case, with a potential accuracy of + or - 0.0021 inches achievable by improved temperature control.

  14. Accuracy requirements of optical linear algebra processors in adaptive optics imaging systems

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Goodman, Joseph W.

    1989-01-01

    The accuracy requirements of optical processors in adaptive optics systems are determined by estimating the required accuracy in a general optical linear algebra processor (OLAP) that results in a smaller average residual aberration than that achieved with a conventional electronic digital processor with some specific computation speed. Special attention is given to an error analysis of a general OLAP with regard to the residual aberration that is created in an adaptive mirror system by the inaccuracies of the processor, and to the effect of computational speed of an electronic processor on the correction. Results are presented on the ability of an OLAP to compete with a digital processor in various situations.

  15. Improving the accuracy of brain tumor surgery via Raman-based technology.

    PubMed

    Hollon, Todd; Lewis, Spencer; Freudiger, Christian W; Sunney Xie, X; Orringer, Daniel A

    2016-03-01

    Despite advances in the surgical management of brain tumors, achieving optimal surgical results and identification of tumor remains a challenge. Raman spectroscopy, a laser-based technique that can be used to nondestructively differentiate molecules based on the inelastic scattering of light, is being applied toward improving the accuracy of brain tumor surgery. Here, the authors systematically review the application of Raman spectroscopy for guidance during brain tumor surgery. Raman spectroscopy can differentiate normal brain from necrotic and vital glioma tissue in human specimens based on chemical differences, and has recently been shown to differentiate tumor-infiltrated tissues from noninfiltrated tissues during surgery. Raman spectroscopy also forms the basis for coherent Raman scattering (CRS) microscopy, a technique that amplifies spontaneous Raman signals by 10,000-fold, enabling real-time histological imaging without the need for tissue processing, sectioning, or staining. The authors review the relevant basic and translational studies on CRS microscopy as a means of providing real-time intraoperative guidance. Recent studies have demonstrated how CRS can be used to differentiate tumor-infiltrated tissues from noninfiltrated tissues and that it has excellent agreement with traditional histology. Under simulated operative conditions, CRS has been shown to identify tumor margins that would be undetectable using standard bright-field microscopy. In addition, CRS microscopy has been shown to detect tumor in human surgical specimens with near-perfect agreement to standard H & E microscopy. The authors suggest that as the intraoperative application and instrumentation for Raman spectroscopy and imaging matures, it will become an essential component in the neurosurgical armamentarium for identifying residual tumor and improving the surgical management of brain tumors. PMID:26926067

  16. Improving the accuracy of brain tumor surgery via Raman-based technology

    PubMed Central

    Hollon, Todd; Lewis, Spencer; Freudiger, Christian W.; Xie, X. Sunney; Orringer, Daniel A.

    2016-01-01

    Despite advances in the surgical management of brain tumors, achieving optimal surgical results and identification of tumor remains a challenge. Raman spectroscopy, a laser-based technique that can be used to nondestructively differentiate molecules based on the inelastic scattering of light, is being applied toward improving the accuracy of brain tumor surgery. Here, the authors systematically review the application of Raman spectroscopy for guidance during brain tumor surgery. Raman spectroscopy can differentiate normal brain from necrotic and vital glioma tissue in human specimens based on chemical differences, and has recently been shown to differentiate tumor-infiltrated tissues from noninfiltrated tissues during surgery. Raman spectroscopy also forms the basis for coherent Raman scattering (CRS) microscopy, a technique that amplifies spontaneous Raman signals by 10,000-fold, enabling real-time histological imaging without the need for tissue processing, sectioning, or staining. The authors review the relevant basic and translational studies on CRS microscopy as a means of providing real-time intraoperative guidance. Recent studies have demonstrated how CRS can be used to differentiate tumor-infiltrated tissues from noninfiltrated tissues and that it has excellent agreement with traditional histology. Under simulated operative conditions, CRS has been shown to identify tumor margins that would be undetectable using standard bright-field microscopy. In addition, CRS microscopy has been shown to detect tumor in human surgical specimens with near-perfect agreement to standard H & E microscopy. The authors suggest that as the intraoperative application and instrumentation for Raman spectroscopy and imaging matures, it will become an essential component in the neurosurgical armamentarium for identifying residual tumor and improving the surgical management of brain tumors. PMID:26926067

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

    NASA Astrophysics Data System (ADS)

    Clinton, Nicholas; Yu, Le; Gong, Peng

    2015-05-01

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

  18. An alpha particle experiment for chemical analysis of the Martian surface and atmosphere.

    NASA Technical Reports Server (NTRS)

    Economou, T. E.; Turkevich, A. L.; Patterson, J. H.

    1973-01-01

    An alpha particle experiment similar to the one performed successfully on the Surveyor lunar missions is described. It is designed to provide a chemical analysis of the Martian surface and atmosphere. Analyses of rocks of known and unknown compositions have been made under simulated Martian conditions. The accuracies attained are generally comparable to those of the Surveyor lunar analyses. Improvements have been achieved in determining carbon and oxygen, so that a few per cent of water or carbonates in rocks can be detected. Some aspects of the integration of such an experiment with the spacecraft, a possible mission profile, and some other problems associated with a soft-landing mission to Mars are discussed. The importance of such a chemical analysis experiment in answering current questions about the nature and history of Martian surface material and its suitability for life processes is presented.

  19. A two-dimensional numerical simulation of a supersonic, chemically reacting mixing layer

    NASA Technical Reports Server (NTRS)

    Drummond, J. Philip

    1988-01-01

    Research has been undertaken to achieve an improved understanding of physical phenomena present when a supersonic flow undergoes chemical reaction. A detailed understanding of supersonic reacting flows is necessary to successfully develop advanced propulsion systems now planned for use late in this century and beyond. In order to explore such flows, a study was begun to create appropriate physical models for describing supersonic combustion, and to develop accurate and efficient numerical techniques for solving the governing equations that result from these models. From this work, two computer programs were written to study reacting flows. Both programs were constructed to consider the multicomponent diffusion and convection of important chemical species, the finite rate reaction of these species, and the resulting interaction of the fluid mechanics and the chemistry. The first program employed a finite difference scheme for integrating the governing equations, whereas the second used a hybrid Chebyshev pseudospectral technique for improved accuracy.

  20. Delicious Chemicals.

    ERIC Educational Resources Information Center

    Barry, Dana M.

    This paper presents an approach to chemistry and nutrition that focuses on food items that people consider delicious. Information is organized according to three categories of food chemicals that provide energy to the human body: (1) fats and oils; (2) carbohydrates; and (3) proteins. Minerals, vitamins, and additives are also discussed along with…