WorldWideScience

Sample records for tomography error analysis

  1. Quantitative analysis of scaling error compensation methods in dimensional X-ray computed tomography

    DEFF Research Database (Denmark)

    Müller, P.; Hiller, Jochen; Dai, Y.

    2015-01-01

    X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy...... errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball...

  2. Practical, Reliable Error Bars in Quantum Tomography

    OpenAIRE

    Faist, Philippe; Renner, Renato

    2015-01-01

    Precise characterization of quantum devices is usually achieved with quantum tomography. However, most methods which are currently widely used in experiments, such as maximum likelihood estimation, lack a well-justified error analysis. Promising recent methods based on confidence regions are difficult to apply in practice or yield error bars which are unnecessarily large. Here, we propose a practical yet robust method for obtaining error bars. We do so by introducing a novel representation of...

  3. Errors in abdominal computed tomography

    International Nuclear Information System (INIS)

    Stephens, S.; Marting, I.; Dixon, A.K.

    1989-01-01

    Sixty-nine patients are presented in whom a substantial error was made on the initial abdominal computed tomography report. Certain features of these errors have been analysed. In 30 (43.5%) a lesion was simply not recognised (error of observation); in 39 (56.5%) the wrong conclusions were drawn about the nature of normal or abnormal structures (error of interpretation). The 39 errors of interpretation were more complex; in 7 patients an abnormal structure was noted but interpreted as normal, whereas in four a normal structure was thought to represent a lesion. Other interpretive errors included those where the wrong cause for a lesion had been ascribed (24 patients), and those where the abnormality was substantially under-reported (4 patients). Various features of these errors are presented and discussed. Errors were made just as often in relation to small and large lesions. Consultants made as many errors as senior registrar radiologists. It is like that dual reporting is the best method of avoiding such errors and, indeed, this is widely practised in our unit. (Author). 9 refs.; 5 figs.; 1 tab

  4. Systematic Errors in Dimensional X-ray Computed Tomography

    DEFF Research Database (Denmark)

    that it is possible to compensate them. In dimensional X-ray computed tomography (CT), many physical quantities influence the final result. However, it is important to know which factors in CT measurements potentially lead to systematic errors. In this talk, typical error sources in dimensional X-ray CT are discussed...

  5. Errors from Image Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wood, William Monford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    Presenting a systematic study of the standard analysis of rod-pinch radiographs for obtaining quantitative measurements of areal mass densities, and making suggestions for improving the methodology of obtaining quantitative information from radiographed objects.

  6. Analysis of Medication Error Reports

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, Paul D.; Young, Jonathan; Santell, John; Hicks, Rodney; Posse, Christian; Fecht, Barbara A.

    2004-11-15

    In medicine, as in many areas of research, technological innovation and the shift from paper based information to electronic records has created a climate of ever increasing availability of raw data. There has been, however, a corresponding lag in our abilities to analyze this overwhelming mass of data, and classic forms of statistical analysis may not allow researchers to interact with data in the most productive way. This is true in the emerging area of patient safety improvement. Traditionally, a majority of the analysis of error and incident reports has been carried out based on an approach of data comparison, and starts with a specific question which needs to be answered. Newer data analysis tools have been developed which allow the researcher to not only ask specific questions but also to “mine” data: approach an area of interest without preconceived questions, and explore the information dynamically, allowing questions to be formulated based on patterns brought up by the data itself. Since 1991, United States Pharmacopeia (USP) has been collecting data on medication errors through voluntary reporting programs. USP’s MEDMARXsm reporting program is the largest national medication error database and currently contains well over 600,000 records. Traditionally, USP has conducted an annual quantitative analysis of data derived from “pick-lists” (i.e., items selected from a list of items) without an in-depth analysis of free-text fields. In this paper, the application of text analysis and data analysis tools used by Battelle to analyze the medication error reports already analyzed in the traditional way by USP is described. New insights and findings were revealed including the value of language normalization and the distribution of error incidents by day of the week. The motivation for this effort is to gain additional insight into the nature of medication errors to support improvements in medication safety.

  7. Improved characterisation and modelling of measurement errors in electrical resistivity tomography (ERT) surveys

    Science.gov (United States)

    Tso, Chak-Hau Michael; Kuras, Oliver; Wilkinson, Paul B.; Uhlemann, Sebastian; Chambers, Jonathan E.; Meldrum, Philip I.; Graham, James; Sherlock, Emma F.; Binley, Andrew

    2017-11-01

    Measurement errors can play a pivotal role in geophysical inversion. Most inverse models require users to prescribe or assume a statistical model of data errors before inversion. Wrongly prescribed errors can lead to over- or under-fitting of data; however, the derivation of models of data errors is often neglected. With the heightening interest in uncertainty estimation within hydrogeophysics, better characterisation and treatment of measurement errors is needed to provide improved image appraisal. Here we focus on the role of measurement errors in electrical resistivity tomography (ERT). We have analysed two time-lapse ERT datasets: one contains 96 sets of direct and reciprocal data collected from a surface ERT line within a 24 h timeframe; the other is a two-year-long cross-borehole survey at a UK nuclear site with 246 sets of over 50,000 measurements. Our study includes the characterisation of the spatial and temporal behaviour of measurement errors using autocorrelation and correlation coefficient analysis. We find that, in addition to well-known proportionality effects, ERT measurements can also be sensitive to the combination of electrodes used, i.e. errors may not be uncorrelated as often assumed. Based on these findings, we develop a new error model that allows grouping based on electrode number in addition to fitting a linear model to transfer resistance. The new model explains the observed measurement errors better and shows superior inversion results and uncertainty estimates in synthetic examples. It is robust, because it groups errors together based on the electrodes used to make the measurements. The new model can be readily applied to the diagonal data weighting matrix widely used in common inversion methods, as well as to the data covariance matrix in a Bayesian inversion framework. We demonstrate its application using extensive ERT monitoring datasets from the two aforementioned sites.

  8. Uncertainty quantification and error analysis

    Energy Technology Data Exchange (ETDEWEB)

    Higdon, Dave M [Los Alamos National Laboratory; Anderson, Mark C [Los Alamos National Laboratory; Habib, Salman [Los Alamos National Laboratory; Klein, Richard [Los Alamos National Laboratory; Berliner, Mark [OHIO STATE UNIV.; Covey, Curt [LLNL; Ghattas, Omar [UNIV OF TEXAS; Graziani, Carlo [UNIV OF CHICAGO; Seager, Mark [LLNL; Sefcik, Joseph [LLNL; Stark, Philip [UC/BERKELEY; Stewart, James [SNL

    2010-01-01

    UQ studies all sources of error and uncertainty, including: systematic and stochastic measurement error; ignorance; limitations of theoretical models; limitations of numerical representations of those models; limitations on the accuracy and reliability of computations, approximations, and algorithms; and human error. A more precise definition for UQ is suggested below.

  9. Error Analysis in Mathematics. Technical Report #1012

    Science.gov (United States)

    Lai, Cheng-Fei

    2012-01-01

    Error analysis is a method commonly used to identify the cause of student errors when they make consistent mistakes. It is a process of reviewing a student's work and then looking for patterns of misunderstanding. Errors in mathematics can be factual, procedural, or conceptual, and may occur for a number of reasons. Reasons why students make…

  10. An Error Analysis on TFL Learners’ Writings

    Directory of Open Access Journals (Sweden)

    Arif ÇERÇİ

    2016-12-01

    Full Text Available The main purpose of the present study is to identify and represent TFL learners’ writing errors through error analysis. All the learners started learning Turkish as foreign language with A1 (beginner level and completed the process by taking C1 (advanced certificate in TÖMER at Gaziantep University. The data of the present study were collected from 14 students’ writings in proficiency exams for each level. The data were grouped as grammatical, syntactic, spelling, punctuation, and word choice errors. The ratio and categorical distributions of identified errors were analyzed through error analysis. The data were analyzed through statistical procedures in an effort to determine whether error types differ according to the levels of the students. The errors in this study are limited to the linguistic and intralingual developmental errors

  11. Uncertainty analysis in seismic tomography

    Science.gov (United States)

    Owoc, Bartosz; Majdański, Mariusz

    2017-04-01

    Velocity field from seismic travel time tomography depends on several factors like regularization, inversion path, model parameterization etc. The result also strongly depends on an initial velocity model and precision of travel times picking. In this research we test dependence on starting model in layered tomography and compare it with effect of picking precision. Moreover, in our analysis for manual travel times picking the uncertainty distribution is asymmetric. This effect is shifting the results toward faster velocities. For calculation we are using JIVE3D travel time tomographic code. We used data from geo-engineering and industrial scale investigations, which were collected by our team from IG PAS.

  12. Quantum tomography via compressed sensing: error bounds, sample complexity and efficient estimators

    International Nuclear Information System (INIS)

    Flammia, Steven T; Gross, David; Liu, Yi-Kai; Eisert, Jens

    2012-01-01

    Intuitively, if a density operator has small rank, then it should be easier to estimate from experimental data, since in this case only a few eigenvectors need to be learned. We prove two complementary results that confirm this intuition. Firstly, we show that a low-rank density matrix can be estimated using fewer copies of the state, i.e. the sample complexity of tomography decreases with the rank. Secondly, we show that unknown low-rank states can be reconstructed from an incomplete set of measurements, using techniques from compressed sensing and matrix completion. These techniques use simple Pauli measurements, and their output can be certified without making any assumptions about the unknown state. In this paper, we present a new theoretical analysis of compressed tomography, based on the restricted isometry property for low-rank matrices. Using these tools, we obtain near-optimal error bounds for the realistic situation where the data contain noise due to finite statistics, and the density matrix is full-rank with decaying eigenvalues. We also obtain upper bounds on the sample complexity of compressed tomography, and almost-matching lower bounds on the sample complexity of any procedure using adaptive sequences of Pauli measurements. Using numerical simulations, we compare the performance of two compressed sensing estimators—the matrix Dantzig selector and the matrix Lasso—with standard maximum-likelihood estimation (MLE). We find that, given comparable experimental resources, the compressed sensing estimators consistently produce higher fidelity state reconstructions than MLE. In addition, the use of an incomplete set of measurements leads to faster classical processing with no loss of accuracy. Finally, we show how to certify the accuracy of a low-rank estimate using direct fidelity estimation, and describe a method for compressed quantum process tomography that works for processes with small Kraus rank and requires only Pauli eigenstate preparations

  13. Analysis of error patterns in clinical radiotherapy

    International Nuclear Information System (INIS)

    Macklis, Roger; Meier, Tim; Barrett, Patricia; Weinhous, Martin

    1996-01-01

    Purpose: Until very recently, prescription errors and adverse treatment events have rarely been studied or reported systematically in oncology. We wished to understand the spectrum and severity of radiotherapy errors that take place on a day-to-day basis in a high-volume academic practice and to understand the resource needs and quality assurance challenges placed on a department by rapid upswings in contract-based clinical volumes requiring additional operating hours, procedures, and personnel. The goal was to define clinical benchmarks for operating safety and to detect error-prone treatment processes that might function as 'early warning' signs. Methods: A multi-tiered prospective and retrospective system for clinical error detection and classification was developed, with formal analysis of the antecedents and consequences of all deviations from prescribed treatment delivery, no matter how trivial. A department-wide record-and-verify system was operational during this period and was used as one method of treatment verification and error detection. Brachytherapy discrepancies were analyzed separately. Results: During the analysis year, over 2000 patients were treated with over 93,000 individual fields. A total of 59 errors affecting a total of 170 individual treated fields were reported or detected during this period. After review, all of these errors were classified as Level 1 (minor discrepancy with essentially no potential for negative clinical implications). This total treatment delivery error rate (170/93, 332 or 0.18%) is significantly better than corresponding error rates reported for other hospital and oncology treatment services, perhaps reflecting the relatively sophisticated error avoidance and detection procedures used in modern clinical radiation oncology. Error rates were independent of linac model and manufacturer, time of day (normal operating hours versus late evening or early morning) or clinical machine volumes. There was some relationship to

  14. Notes on human error analysis and prediction

    International Nuclear Information System (INIS)

    Rasmussen, J.

    1978-11-01

    The notes comprise an introductory discussion of the role of human error analysis and prediction in industrial risk analysis. Following this introduction, different classes of human errors and role in industrial systems are mentioned. Problems related to the prediction of human behaviour in reliability and safety analysis are formulated and ''criteria for analyzability'' which must be met by industrial systems so that a systematic analysis can be performed are suggested. The appendices contain illustrative case stories and a review of human error reports for the task of equipment calibration and testing as found in the US Licensee Event Reports. (author)

  15. A Comparative Study on Error Analysis

    DEFF Research Database (Denmark)

    Wu, Xiaoli; Zhang, Chun

    2015-01-01

    Title: A Comparative Study on Error Analysis Subtitle: - Belgian (L1) and Danish (L1) learners’ use of Chinese (L2) comparative sentences in written production Xiaoli Wu, Chun Zhang Abstract: Making errors is an inevitable and necessary part of learning. The collection, classification and analysis...... the occurrence of errors either in linguistic or pedagogical terms. The purpose of the current study is to demonstrate the theoretical and practical relevance of error analysis approach in CFL by investigating two cases - (1) Belgian (L1) learners’ use of Chinese (L2) comparative sentences in written production...... of errors in the written and spoken production of L2 learners has a long tradition in L2 pedagogy. Yet, in teaching and learning Chinese as a foreign language (CFL), only handful studies have been made either to define the ‘error’ in a pedagogically insightful way or to empirically investigate...

  16. Error estimation in plant growth analysis

    Directory of Open Access Journals (Sweden)

    Andrzej Gregorczyk

    2014-01-01

    Full Text Available The scheme is presented for calculation of errors of dry matter values which occur during approximation of data with growth curves, determined by the analytical method (logistic function and by the numerical method (Richards function. Further formulae are shown, which describe absolute errors of growth characteristics: Growth rate (GR, Relative growth rate (RGR, Unit leaf rate (ULR and Leaf area ratio (LAR. Calculation examples concerning the growth course of oats and maize plants are given. The critical analysis of the estimation of obtained results has been done. The purposefulness of joint application of statistical methods and error calculus in plant growth analysis has been ascertained.

  17. A review of setup error in supine breast radiotherapy using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Batumalai, Vikneswary, E-mail: Vikneswary.batumalai@sswahs.nsw.gov.au [South Western Clinical School, University of New South Wales, Sydney, New South Wales (Australia); Liverpool and Macarthur Cancer Therapy Centres, New South Wales (Australia); Ingham Institute of Applied Medical Research, Sydney, New South Wales (Australia); Holloway, Lois [South Western Clinical School, University of New South Wales, Sydney, New South Wales (Australia); Liverpool and Macarthur Cancer Therapy Centres, New South Wales (Australia); Ingham Institute of Applied Medical Research, Sydney, New South Wales (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales (Australia); Delaney, Geoff P. [South Western Clinical School, University of New South Wales, Sydney, New South Wales (Australia); Liverpool and Macarthur Cancer Therapy Centres, New South Wales (Australia); Ingham Institute of Applied Medical Research, Sydney, New South Wales (Australia)

    2016-10-01

    Setup error in breast radiotherapy (RT) measured with 3-dimensional cone-beam computed tomography (CBCT) is becoming more common. The purpose of this study is to review the literature relating to the magnitude of setup error in breast RT measured with CBCT. The different methods of image registration between CBCT and planning computed tomography (CT) scan were also explored. A literature search, not limited by date, was conducted using Medline and Google Scholar with the following key words: breast cancer, RT, setup error, and CBCT. This review includes studies that reported on systematic and random errors, and the methods used when registering CBCT scans with planning CT scan. A total of 11 relevant studies were identified for inclusion in this review. The average magnitude of error is generally less than 5 mm across a number of studies reviewed. The common registration methods used when registering CBCT scans with planning CT scan are based on bony anatomy, soft tissue, and surgical clips. No clear relationships between the setup errors detected and methods of registration were observed from this review. Further studies are needed to assess the benefit of CBCT over electronic portal image, as CBCT remains unproven to be of wide benefit in breast RT.

  18. A review of setup error in supine breast radiotherapy using cone-beam computed tomography

    International Nuclear Information System (INIS)

    Batumalai, Vikneswary; Holloway, Lois; Delaney, Geoff P.

    2016-01-01

    Setup error in breast radiotherapy (RT) measured with 3-dimensional cone-beam computed tomography (CBCT) is becoming more common. The purpose of this study is to review the literature relating to the magnitude of setup error in breast RT measured with CBCT. The different methods of image registration between CBCT and planning computed tomography (CT) scan were also explored. A literature search, not limited by date, was conducted using Medline and Google Scholar with the following key words: breast cancer, RT, setup error, and CBCT. This review includes studies that reported on systematic and random errors, and the methods used when registering CBCT scans with planning CT scan. A total of 11 relevant studies were identified for inclusion in this review. The average magnitude of error is generally less than 5 mm across a number of studies reviewed. The common registration methods used when registering CBCT scans with planning CT scan are based on bony anatomy, soft tissue, and surgical clips. No clear relationships between the setup errors detected and methods of registration were observed from this review. Further studies are needed to assess the benefit of CBCT over electronic portal image, as CBCT remains unproven to be of wide benefit in breast RT.

  19. Human Error Analysis by Fuzzy-Set

    International Nuclear Information System (INIS)

    Situmorang, Johnny

    1996-01-01

    In conventional HRA the probability of Error is treated as a single and exact value through constructing even tree, but in this moment the Fuzzy-Set Theory is used. Fuzzy set theory treat the probability of error as a plausibility which illustrate a linguistic variable. Most parameter or variable in human engineering been defined verbal good, fairly good, worst etc. Which describe a range of any value of probability. For example this analysis is quantified the human error in calibration task, and the probability of miscalibration is very low

  20. Analysis of field errors in existing undulators

    International Nuclear Information System (INIS)

    Kincaid, B.M.

    1990-01-01

    The Advanced Light Source (ALS) and other third generation synchrotron light sources have been designed for optimum performance with undulator insertion devices. The performance requirements for these new undulators are explored, with emphasis on the effects of errors on source spectral brightness. Analysis of magnetic field data for several existing hybrid undulators is presented, decomposing errors into systematic and random components. An attempts is made to identify the sources of these errors, and recommendations are made for designing future insertion devices. 12 refs., 16 figs

  1. Batch Computed Tomography Analysis of Projectiles

    Science.gov (United States)

    2016-05-01

    ARL-TR-7681 ● MAY 2016 US Army Research Laboratory Batch Computed Tomography Analysis of Projectiles by Michael C Golt, Chris M...Laboratory Batch Computed Tomography Analysis of Projectiles by Michael C Golt and Matthew S Bratcher Weapons and Materials Research...values to account for projectile variability in the ballistic evaluation of armor. 15. SUBJECT TERMS computed tomography , CT, BS41, projectiles

  2. Error propagation analysis for a sensor system

    International Nuclear Information System (INIS)

    Yeater, M.L.; Hockenbury, R.W.; Hawkins, J.; Wilkinson, J.

    1976-01-01

    As part of a program to develop reliability methods for operational use with reactor sensors and protective systems, error propagation analyses are being made for each model. An example is a sensor system computer simulation model, in which the sensor system signature is convoluted with a reactor signature to show the effect of each in revealing or obscuring information contained in the other. The error propagation analysis models the system and signature uncertainties and sensitivities, whereas the simulation models the signatures and by extensive repetitions reveals the effect of errors in various reactor input or sensor response data. In the approach for the example presented, the errors accumulated by the signature (set of ''noise'' frequencies) are successively calculated as it is propagated stepwise through a system comprised of sensor and signal processing components. Additional modeling steps include a Fourier transform calculation to produce the usual power spectral density representation of the product signature, and some form of pattern recognition algorithm

  3. Numeracy, Literacy and Newman's Error Analysis

    Science.gov (United States)

    White, Allan Leslie

    2010-01-01

    Newman (1977, 1983) defined five specific literacy and numeracy skills as crucial to performance on mathematical word problems: reading, comprehension, transformation, process skills, and encoding. Newman's Error Analysis (NEA) provided a framework for considering the reasons that underlay the difficulties students experienced with mathematical…

  4. Analysis of the interface tracking errors

    International Nuclear Information System (INIS)

    Cerne, G.; Tiselj, I.; Petelin, S.

    2001-01-01

    An important limitation of the interface-tracking algorithm is the grid density, which determines the space scale of the surface tracking. In this paper the analysis of the interface tracking errors, which occur in a dispersed flow, is performed for the VOF interface tracking method. A few simple two-fluid tests are proposed for the investigation of the interface tracking errors and their grid dependence. When the grid density becomes too coarse to follow the interface changes, the errors can be reduced either by using denser nodalization or by switching to the two-fluid model during the simulation. Both solutions are analyzed and compared on a simple vortex-flow test.(author)

  5. Error analysis of stochastic gradient descent ranking.

    Science.gov (United States)

    Chen, Hong; Tang, Yi; Li, Luoqing; Yuan, Yuan; Li, Xuelong; Tang, Yuanyan

    2013-06-01

    Ranking is always an important task in machine learning and information retrieval, e.g., collaborative filtering, recommender systems, drug discovery, etc. A kernel-based stochastic gradient descent algorithm with the least squares loss is proposed for ranking in this paper. The implementation of this algorithm is simple, and an expression of the solution is derived via a sampling operator and an integral operator. An explicit convergence rate for leaning a ranking function is given in terms of the suitable choices of the step size and the regularization parameter. The analysis technique used here is capacity independent and is novel in error analysis of ranking learning. Experimental results on real-world data have shown the effectiveness of the proposed algorithm in ranking tasks, which verifies the theoretical analysis in ranking error.

  6. Impact of errors in experimental parameters on reconstructed breast images using diffuse optical tomography.

    Science.gov (United States)

    Deng, Bin; Lundqvist, Mats; Fang, Qianqian; Carp, Stefan A

    2018-03-01

    Near-infrared diffuse optical tomography (NIR-DOT) is an emerging technology that offers hemoglobin based, functional imaging tumor biomarkers for breast cancer management. The most promising clinical translation opportunities are in the differential diagnosis of malignant vs. benign lesions, and in early response assessment and guidance for neoadjuvant chemotherapy. Accurate quantification of the tissue oxy- and deoxy-hemoglobin concentration across the field of view, as well as repeatability during longitudinal imaging in the context of therapy guidance, are essential for the successful translation of NIR-DOT to clinical practice. The ill-posed and ill-condition nature of the DOT inverse problem makes this technique particularly susceptible to model errors that may occur, for example, when the experimental conditions do not fully match the assumptions built into the image reconstruction process. To evaluate the susceptibility of DOT images to experimental errors that might be encountered in practice for a parallel-plate NIR-DOT system, we simulated 7 different types of errors, each with a range of magnitudes. We generated simulated data by using digital breast phantoms derived from five actual mammograms of healthy female volunteers, to which we added a 1-cm tumor. After applying each of the experimental error types and magnitudes to the simulated measurements, we reconstructed optical images with and without structural prior guidance and assessed the overall error in the total hemoglobin concentrations (HbT) and in the HbT contrast between the lesion and surrounding area vs. the best-case scenarios. It is found that slight in-plane probe misalignment and plate rotation did not result in large quantification errors. However, any out-of-plane probe tilting could result in significant deterioration in lesion contrast. Among the error types investigated in this work, optical images were the least likely to be impacted by breast shape inaccuracies but suffered the

  7. Error begat error: design error analysis and prevention in social infrastructure projects.

    Science.gov (United States)

    Love, Peter E D; Lopez, Robert; Edwards, David J; Goh, Yang M

    2012-09-01

    Design errors contribute significantly to cost and schedule growth in social infrastructure projects and to engineering failures, which can result in accidents and loss of life. Despite considerable research that has addressed their error causation in construction projects they still remain prevalent. This paper identifies the underlying conditions that contribute to design errors in social infrastructure projects (e.g. hospitals, education, law and order type buildings). A systemic model of error causation is propagated and subsequently used to develop a learning framework for design error prevention. The research suggests that a multitude of strategies should be adopted in congruence to prevent design errors from occurring and so ensure that safety and project performance are ameliorated. Copyright © 2011. Published by Elsevier Ltd.

  8. Data analysis in emission tomography using emission-count posteriors

    International Nuclear Information System (INIS)

    Sitek, Arkadiusz

    2012-01-01

    A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography. (paper)

  9. Data analysis in emission tomography using emission-count posteriors

    Science.gov (United States)

    Sitek, Arkadiusz

    2012-11-01

    A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography.

  10. Error Analysis of Determining Airplane Location by Global Positioning System

    OpenAIRE

    Hajiyev, Chingiz; Burat, Alper

    1999-01-01

    This paper studies the error analysis of determining airplane location by global positioning system (GPS) using statistical testing method. The Newton Rhapson method positions the airplane at the intersection point of four spheres. Absolute errors, relative errors and standard deviation have been calculated The results show that the positioning error of the airplane varies with the coordinates of GPS satellite and the airplane.

  11. A study on mechanical errors in Cone Beam Computed Tomography (CBCT) System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yi Seong; Yoo, Eun Jeong; Choi, Kyoung Sik [Dept. of Radiation Oncology, Anyang SAM Hospital, Anyang (Korea, Republic of); Lee, Jong Woo [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of); Suh, Tae Suk [Dept. of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Jeong Koo [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2013-06-15

    This study investigated the rate of setup variance by the rotating unbalance of gantry in image-guided radiation therapy. The equipments used linear accelerator(Elekta Synergy ™, UK) and a three-dimensional volume imaging mode(3D Volume View) in cone beam computed tomography(CBCT) system. 2D images obtained by rotating 360°and 180° were reconstructed to 3D image. Catpan503 phantom and homogeneous phantom were used to measure the setup errors. Ball-bearing phantom was used to check the rotation axis of the CBCT. The volume image from CBCT using Catphan503 phantom and homogeneous phantom were analyzed and compared to images from conventional CT in the six dimensional view(X, Y, Z, Roll, Pitch, and Yaw). The variance ratio of setup error were difference in X 0.6 mm, Y 0.5 mm, Z 0.5 mm when the gantry rotated 360° in orthogonal coordinate. whereas rotated 180°, the error measured 0.9 mm, 0.2 mm, 0.3 mm in X, Y, Z respectively. In the rotating coordinates, the more increased the rotating unbalance, the more raised average ratio of setup errors. The resolution of CBCT images showed 2 level of difference in the table recommended. CBCT had a good agreement compared to each recommended values which is the mechanical safety, geometry accuracy and image quality. The rotating unbalance of gentry vary hardly in orthogonal coordinate. However, in rotating coordinate of gantry exceeded the ±1° of recommended value. Therefore, when we do sophisticated radiation therapy six dimensional correction is needed.

  12. Analysis of errors in forensic science

    Directory of Open Access Journals (Sweden)

    Mingxiao Du

    2017-01-01

    Full Text Available Reliability of expert testimony is one of the foundations of judicial justice. Both expert bias and scientific errors affect the reliability of expert opinion, which in turn affects the trustworthiness of the findings of fact in legal proceedings. Expert bias can be eliminated by replacing experts; however, it may be more difficult to eliminate scientific errors. From the perspective of statistics, errors in operation of forensic science include systematic errors, random errors, and gross errors. In general, process repetition and abiding by the standard ISO/IEC:17025: 2005, general requirements for the competence of testing and calibration laboratories, during operation are common measures used to reduce errors that originate from experts and equipment, respectively. For example, to reduce gross errors, the laboratory can ensure that a test is repeated several times by different experts. In applying for forensic principles and methods, the Federal Rules of Evidence 702 mandate that judges consider factors such as peer review, to ensure the reliability of the expert testimony. As the scientific principles and methods may not undergo professional review by specialists in a certain field, peer review serves as an exclusive standard. This study also examines two types of statistical errors. As false-positive errors involve a higher possibility of an unfair decision-making, they should receive more attention than false-negative errors.

  13. [Analysis of intrusion errors in free recall].

    Science.gov (United States)

    Diesfeldt, H F A

    2017-06-01

    Extra-list intrusion errors during five trials of the eight-word list-learning task of the Amsterdam Dementia Screening Test (ADST) were investigated in 823 consecutive psychogeriatric patients (87.1% suffering from major neurocognitive disorder). Almost half of the participants (45.9%) produced one or more intrusion errors on the verbal recall test. Correct responses were lower when subjects made intrusion errors, but learning slopes did not differ between subjects who committed intrusion errors and those who did not so. Bivariate regression analyses revealed that participants who committed intrusion errors were more deficient on measures of eight-word recognition memory, delayed visual recognition and tests of executive control (the Behavioral Dyscontrol Scale and the ADST-Graphical Sequences as measures of response inhibition). Using hierarchical multiple regression, only free recall and delayed visual recognition retained an independent effect in the association with intrusion errors, such that deficient scores on tests of episodic memory were sufficient to explain the occurrence of intrusion errors. Measures of inhibitory control did not add significantly to the explanation of intrusion errors in free recall, which makes insufficient strength of memory traces rather than a primary deficit in inhibition the preferred account for intrusion errors in free recall.

  14. A technique for human error analysis (ATHEANA)

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, S.E.; Ramey-Smith, A.M.; Wreathall, J.; Parry, G.W. [and others

    1996-05-01

    Probabilistic risk assessment (PRA) has become an important tool in the nuclear power industry, both for the Nuclear Regulatory Commission (NRC) and the operating utilities. Human reliability analysis (HRA) is a critical element of PRA; however, limitations in the analysis of human actions in PRAs have long been recognized as a constraint when using PRA. A multidisciplinary HRA framework has been developed with the objective of providing a structured approach for analyzing operating experience and understanding nuclear plant safety, human error, and the underlying factors that affect them. The concepts of the framework have matured into a rudimentary working HRA method. A trial application of the method has demonstrated that it is possible to identify potentially significant human failure events from actual operating experience which are not generally included in current PRAs, as well as to identify associated performance shaping factors and plant conditions that have an observable impact on the frequency of core damage. A general process was developed, albeit in preliminary form, that addresses the iterative steps of defining human failure events and estimating their probabilities using search schemes. Additionally, a knowledge- base was developed which describes the links between performance shaping factors and resulting unsafe actions.

  15. A technique for human error analysis (ATHEANA)

    International Nuclear Information System (INIS)

    Cooper, S.E.; Ramey-Smith, A.M.; Wreathall, J.; Parry, G.W.

    1996-05-01

    Probabilistic risk assessment (PRA) has become an important tool in the nuclear power industry, both for the Nuclear Regulatory Commission (NRC) and the operating utilities. Human reliability analysis (HRA) is a critical element of PRA; however, limitations in the analysis of human actions in PRAs have long been recognized as a constraint when using PRA. A multidisciplinary HRA framework has been developed with the objective of providing a structured approach for analyzing operating experience and understanding nuclear plant safety, human error, and the underlying factors that affect them. The concepts of the framework have matured into a rudimentary working HRA method. A trial application of the method has demonstrated that it is possible to identify potentially significant human failure events from actual operating experience which are not generally included in current PRAs, as well as to identify associated performance shaping factors and plant conditions that have an observable impact on the frequency of core damage. A general process was developed, albeit in preliminary form, that addresses the iterative steps of defining human failure events and estimating their probabilities using search schemes. Additionally, a knowledge- base was developed which describes the links between performance shaping factors and resulting unsafe actions

  16. Phase analysis in gated blood pool tomography

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Tada, Akira; Taki, Junichi; Nanbu, Ichiro

    1984-01-01

    Phase analysis of gated blood pool study has been applied to detect the site of accessory conduction pathway (ACP) in the Wolff-Parkinson-White (WPW) syndrome; however, there was a limitation to detect the precise location of ACP by phase analysis alone. In this study, we applied phase analysis to gated blood pool tomography using seven pin hole tomography (7PT) and gated emission computed tomography (GECT) in 21 patients with WPW syndrome and 3 normal subjects. In 17 patients, the sites of ACPs were confirmed by epicardial mapping and the result of the surgical division of ACP. In 7PT, the site of ACP grossly agreed to the abnormal initial phase in phase image in 5 out of 6 patients with left cardiac type. In GECT, phase images were generated in short axial, vertical and horizontal long axial sections. In 8 out of 9 patients, the site of ACP was correctly identified by phase images, and in a patient who had two ACPs, initial phase corresponded to one of the two locations. Phase analysis of gated blood pool tomography has advantages for avoiding overlap of blood pools and for estimating three-dimensional propagation of the contraction, and can be a good adjunctive method in patients with WPW syndrome. (author)

  17. Teacher knowledge of error analysis in differential calculus

    Directory of Open Access Journals (Sweden)

    Eunice K. Moru

    2014-12-01

    Full Text Available The study investigated teacher knowledge of error analysis in differential calculus. Two teachers were the sample of the study: one a subject specialist and the other a mathematics education specialist. Questionnaires and interviews were used for data collection. The findings of the study reflect that the teachers’ knowledge of error analysis was characterised by the following assertions, which are backed up with some evidence: (1 teachers identified the errors correctly, (2 the generalised error identification resulted in opaque analysis, (3 some of the identified errors were not interpreted from multiple perspectives, (4 teachers’ evaluation of errors was either local or global and (5 in remedying errors accuracy and efficiency were emphasised more than conceptual understanding. The implications of the findings of the study for teaching include engaging in error analysis continuously as this is one way of improving knowledge for teaching.

  18. Fixturing error measurement and analysis using CMMs

    International Nuclear Information System (INIS)

    Wang, Y; Chen, X; Gindy, N

    2005-01-01

    Influence of fixture on the errors of a machined surface can be very significant. The machined surface errors generated during machining can be measured by using a coordinate measurement machine (CMM) through the displacements of three coordinate systems on a fixture-workpiece pair in relation to the deviation of the machined surface. The surface errors consist of the component movement, component twist, deviation between actual machined surface and defined tool path. A turbine blade fixture for grinding operation is used for case study

  19. Detection of anomalies in radio tomography of asteroids: Source count and forward errors

    Science.gov (United States)

    Pursiainen, S.; Kaasalainen, M.

    2014-09-01

    The purpose of this study was to advance numerical methods for radio tomography in which asteroid's internal electric permittivity distribution is to be recovered from radio frequency data gathered by an orbiter. The focus was on signal generation via multiple sources (transponders) providing one potential, or even essential, scenario to be implemented in a challenging in situ measurement environment and within tight payload limits. As a novel feature, the effects of forward errors including noise and a priori uncertainty of the forward (data) simulation were examined through a combination of the iterative alternating sequential (IAS) inverse algorithm and finite-difference time-domain (FDTD) simulation of time evolution data. Single and multiple source scenarios were compared in two-dimensional localization of permittivity anomalies. Three different anomaly strengths and four levels of total noise were tested. Results suggest, among other things, that multiple sources can be necessary to obtain appropriate results, for example, to distinguish three separate anomalies with permittivity less or equal than half of the background value, relevant in recovery of internal cavities.

  20. Asteroid orbital error analysis: Theory and application

    Science.gov (United States)

    Muinonen, K.; Bowell, Edward

    1992-01-01

    We present a rigorous Bayesian theory for asteroid orbital error estimation in which the probability density of the orbital elements is derived from the noise statistics of the observations. For Gaussian noise in a linearized approximation the probability density is also Gaussian, and the errors of the orbital elements at a given epoch are fully described by the covariance matrix. The law of error propagation can then be applied to calculate past and future positional uncertainty ellipsoids (Cappellari et al. 1976, Yeomans et al. 1987, Whipple et al. 1991). To our knowledge, this is the first time a Bayesian approach has been formulated for orbital element estimation. In contrast to the classical Fisherian school of statistics, the Bayesian school allows a priori information to be formally present in the final estimation. However, Bayesian estimation does give the same results as Fisherian estimation when no priori information is assumed (Lehtinen 1988, and reference therein).

  1. Analysis of errors of radiation relay, (1)

    International Nuclear Information System (INIS)

    Koyanagi, Takami; Nakajima, Sinichi

    1976-01-01

    The statistical error of liquid level controlled by radiation relay is analysed and a method of minimizing the error is proposed. This method comes to the problem of optimum setting of the time constant of radiation relay. The equations for obtaining the value of time constant are presented and the numerical results are shown in a table and plotted in a figure. The optimum time constant of the upper level control relay is entirely different from that of the lower level control relay. (auth.)

  2. Resection plane-dependent error in computed tomography volumetry of the right hepatic lobe in living liver donors

    Directory of Open Access Journals (Sweden)

    Heon-Ju Kwon

    2018-03-01

    Full Text Available Background/Aims Computed tomography (CT hepatic volumetry is currently accepted as the most reliable method for preoperative estimation of graft weight in living donor liver transplantation (LDLT. However, several factors can cause inaccuracies in CT volumetry compared to real graft weight. The purpose of this study was to determine the frequency and degree of resection plane-dependent error in CT volumetry of the right hepatic lobe in LDLT. Methods Forty-six living liver donors underwent CT before donor surgery and on postoperative day 7. Prospective CT volumetry (VP was measured via the assumptive hepatectomy plane. Retrospective liver volume (VR was measured using the actual plane by comparing preoperative and postoperative CT. Compared with intraoperatively measured weight (W, errors in percentage (% VP and VR were evaluated. Plane-dependent error in VP was defined as the absolute difference between VP and VR. % plane-dependent error was defined as follows: |VP–VR|/W∙100. Results Mean VP, VR, and W were 761.9 mL, 755.0 mL, and 696.9 g. Mean and % errors in VP were 73.3 mL and 10.7%. Mean error and % error in VR were 64.4 mL and 9.3%. Mean plane-dependent error in VP was 32.4 mL. Mean % plane-dependent error was 4.7%. Plane-dependent error in VP exceeded 10% of W in approximately 10% of the subjects in our study. Conclusions There was approximately 5% plane-dependent error in liver VP on CT volumetry. Plane-dependent error in VP exceeded 10% of W in approximately 10% of LDLT donors in our study. This error should be considered, especially when CT volumetry is performed by a less experienced operator who is not well acquainted with the donor hepatectomy plane.

  3. Resection plane-dependent error in computed tomography volumetry of the right hepatic lobe in living liver donors.

    Science.gov (United States)

    Kwon, Heon-Ju; Kim, Kyoung Won; Kim, Bohyun; Kim, So Yeon; Lee, Chul Seung; Lee, Jeongjin; Song, Gi Won; Lee, Sung Gyu

    2018-03-01

    Computed tomography (CT) hepatic volumetry is currently accepted as the most reliable method for preoperative estimation of graft weight in living donor liver transplantation (LDLT). However, several factors can cause inaccuracies in CT volumetry compared to real graft weight. The purpose of this study was to determine the frequency and degree of resection plane-dependent error in CT volumetry of the right hepatic lobe in LDLT. Forty-six living liver donors underwent CT before donor surgery and on postoperative day 7. Prospective CT volumetry (V P ) was measured via the assumptive hepatectomy plane. Retrospective liver volume (V R ) was measured using the actual plane by comparing preoperative and postoperative CT. Compared with intraoperatively measured weight (W), errors in percentage (%) V P and V R were evaluated. Plane-dependent error in V P was defined as the absolute difference between V P and V R . % plane-dependent error was defined as follows: |V P -V R |/W∙100. Mean V P , V R , and W were 761.9 mL, 755.0 mL, and 696.9 g. Mean and % errors in V P were 73.3 mL and 10.7%. Mean error and % error in V R were 64.4 mL and 9.3%. Mean plane-dependent error in V P was 32.4 mL. Mean % plane-dependent error was 4.7%. Plane-dependent error in V P exceeded 10% of W in approximately 10% of the subjects in our study. There was approximately 5% plane-dependent error in liver V P on CT volumetry. Plane-dependent error in V P exceeded 10% of W in approximately 10% of LDLT donors in our study. This error should be considered, especially when CT volumetry is performed by a less experienced operator who is not well acquainted with the donor hepatectomy plane.

  4. Dose error analysis for a scanned proton beam delivery system

    International Nuclear Information System (INIS)

    Coutrakon, G; Wang, N; Miller, D W; Yang, Y

    2010-01-01

    All particle beam scanning systems are subject to dose delivery errors due to errors in position, energy and intensity of the delivered beam. In addition, finite scan speeds, beam spill non-uniformities, and delays in detector, detector electronics and magnet responses will all contribute errors in delivery. In this paper, we present dose errors for an 8 x 10 x 8 cm 3 target of uniform water equivalent density with 8 cm spread out Bragg peak and a prescribed dose of 2 Gy. Lower doses are also analyzed and presented later in the paper. Beam energy errors and errors due to limitations of scanning system hardware have been included in the analysis. By using Gaussian shaped pencil beams derived from measurements in the research room of the James M Slater Proton Treatment and Research Center at Loma Linda, CA and executing treatment simulations multiple times, statistical dose errors have been calculated in each 2.5 mm cubic voxel in the target. These errors were calculated by delivering multiple treatments to the same volume and calculating the rms variation in delivered dose at each voxel in the target. The variations in dose were the result of random beam delivery errors such as proton energy, spot position and intensity fluctuations. The results show that with reasonable assumptions of random beam delivery errors, the spot scanning technique yielded an rms dose error in each voxel less than 2% or 3% of the 2 Gy prescribed dose. These calculated errors are within acceptable clinical limits for radiation therapy.

  5. Analysis of Errors in a Special Perturbations Satellite Orbit Propagator

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, M.; Jones, J.P.

    1999-02-01

    We performed an analysis of error densities for the Special Perturbations orbit propagator using data for 29 satellites in orbits of interest to Space Shuttle and International Space Station collision avoidance. We find that the along-track errors predominate. These errors increase monotonically over each 36-hour prediction interval. The predicted positions in the along-track direction progressively either leap ahead of or lag behind the actual positions. Unlike the along-track errors the radial and cross-track errors oscillate about their nearly zero mean values. As the number of observations per fit interval decline the along-track prediction errors, and amplitudes of the radial and cross-track errors, increase.

  6. ERROR ANALYSIS ON INFORMATION AND TECHNOLOGY STUDENTS’ SENTENCE WRITING ASSIGNMENTS

    Directory of Open Access Journals (Sweden)

    Rentauli Mariah Silalahi

    2015-03-01

    Full Text Available Students’ error analysis is very important for helping EFL teachers to develop their teaching materials, assessments and methods. However, it takes much time and effort from the teachers to do such an error analysis towards their students’ language. This study seeks to identify the common errors made by 1 class of 28 freshmen students studying English in their first semester in an IT university. The data is collected from their writing assignments for eight consecutive weeks. The errors found were classified into 24 types and the top ten most common errors committed by the students were article, preposition, spelling, word choice, subject-verb agreement, auxiliary verb, plural form, verb form, capital letter, and meaningless sentences. The findings about the students’ frequency of committing errors were, then, contrasted to their midterm test result and in order to find out the reasons behind the error recurrence; the students were given some questions to answer in a questionnaire format. Most of the students admitted that careless was the major reason for their errors and lack understanding came next. This study suggests EFL teachers to devote their time to continuously check the students’ language by giving corrections so that the students can learn from their errors and stop committing the same errors.

  7. Trial application of a technique for human error analysis (ATHEANA)

    International Nuclear Information System (INIS)

    Bley, D.C.; Cooper, S.E.; Parry, G.W.

    1996-01-01

    The new method for HRA, ATHEANA, has been developed based on a study of the operating history of serious accidents and an understanding of the reasons why people make errors. Previous publications associated with the project have dealt with the theoretical framework under which errors occur and the retrospective analysis of operational events. This is the first attempt to use ATHEANA in a prospective way, to select and evaluate human errors within the PSA context

  8. Analysis of Medication Errors in Simulated Pediatric Resuscitation by Residents

    Directory of Open Access Journals (Sweden)

    Evelyn Porter

    2014-07-01

    Full Text Available Introduction: The objective of our study was to estimate the incidence of prescribing medication errors specifically made by a trainee and identify factors associated with these errors during the simulated resuscitation of a critically ill child. Methods: The results of the simulated resuscitation are described. We analyzed data from the simulated resuscitation for the occurrence of a prescribing medication error. We compared univariate analysis of each variable to medication error rate and performed a separate multiple logistic regression analysis on the significant univariate variables to assess the association between the selected variables. Results: We reviewed 49 simulated resuscitations . The final medication error rate for the simulation was 26.5% (95% CI 13.7% - 39.3%. On univariate analysis, statistically significant findings for decreased prescribing medication error rates included senior residents in charge, presence of a pharmacist, sleeping greater than 8 hours prior to the simulation, and a visual analog scale score showing more confidence in caring for critically ill children. Multiple logistic regression analysis using the above significant variables showed only the presence of a pharmacist to remain significantly associated with decreased medication error, odds ratio of 0.09 (95% CI 0.01 - 0.64. Conclusion: Our results indicate that the presence of a clinical pharmacist during the resuscitation of a critically ill child reduces the medication errors made by resident physician trainees.

  9. Error Analysis on Plane-to-Plane Linear Approximate Coordinate ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, the error analysis has been done for the linear approximate transformation between two tangent planes in celestial sphere in a simple case. The results demonstrate that the error from the linear transformation does not meet the requirement of high-precision astrometry under some conditions, so the ...

  10. Improving image quality in Electrical Impedance Tomography (EIT using Projection Error Propagation-based Regularization (PEPR technique: A simulation study

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Bera

    2011-03-01

    Full Text Available A Projection Error Propagation-based Regularization (PEPR method is proposed and the reconstructed image quality is improved in Electrical Impedance Tomography (EIT. A projection error is produced due to the misfit of the calculated and measured data in the reconstruction process. The variation of the projection error is integrated with response matrix in each iterations and the reconstruction is carried out in EIDORS. The PEPR method is studied with the simulated boundary data for different inhomogeneity geometries. Simulated results demonstrate that the PEPR technique improves image reconstruction precision in EIDORS and hence it can be successfully implemented to increase the reconstruction accuracy in EIT.>doi:10.5617/jeb.158 J Electr Bioimp, vol. 2, pp. 2-12, 2011

  11. Error analysis of nuclear power plant operator cognitive behavior

    International Nuclear Information System (INIS)

    He Xuhong; Zhao Bingquan; Chen Yulong

    2001-01-01

    Nuclear power plant is a complex human-machine system integrated with many advanced machines, electron devices and automatic controls. It demands operators to have high cognitive ability and correct analysis skill. The author divides operator's cognitive process into five stages to analysis. With this cognitive model, operator's cognitive error is analysed to get the root causes and stages that error happens. The results of the analysis serve as a basis in design of control rooms and training and evaluation of operators

  12. Nanoparticles displacement analysis using optical coherence tomography

    Science.gov (United States)

    StrÄ kowski, Marcin R.; Kraszewski, Maciej; StrÄ kowska, Paulina

    2016-03-01

    Optical coherence tomography (OCT) is a versatile optical method for cross-sectional and 3D imaging of biological and non-biological objects. Here we are going to present the application of polarization sensitive spectroscopic OCT system (PS-SOCT) for quantitative measurements of materials containing nanoparticles. The PS-SOCT combines the polarization sensitive analysis with time-frequency analysis. In this contribution the benefits of using the combination of timefrequency and polarization sensitive analysis are being expressed. The usefulness of PS-SOCT for nanoparticles evaluation is going to be tested on nanocomposite materials with TiO2 nanoparticles. The OCT measurements results have been compared with SEM examination of the PMMA matrix with nanoparticles. The experiment has proven that by the use of polarization sensitive and spectroscopic OCT the nanoparticles dispersion and size can be evaluated.

  13. Bayesian tomography and integrated data analysis in fusion diagnostics

    Science.gov (United States)

    Li, Dong; Dong, Y. B.; Deng, Wei; Shi, Z. B.; Fu, B. Z.; Gao, J. M.; Wang, T. B.; Zhou, Yan; Liu, Yi; Yang, Q. W.; Duan, X. R.

    2016-11-01

    In this article, a Bayesian tomography method using non-stationary Gaussian process for a prior has been introduced. The Bayesian formalism allows quantities which bear uncertainty to be expressed in the probabilistic form so that the uncertainty of a final solution can be fully resolved from the confidence interval of a posterior probability. Moreover, a consistency check of that solution can be performed by checking whether the misfits between predicted and measured data are reasonably within an assumed data error. In particular, the accuracy of reconstructions is significantly improved by using the non-stationary Gaussian process that can adapt to the varying smoothness of emission distribution. The implementation of this method to a soft X-ray diagnostics on HL-2A has been used to explore relevant physics in equilibrium and MHD instability modes. This project is carried out within a large size inference framework, aiming at an integrated analysis of heterogeneous diagnostics.

  14. Errors of DWPF frit analysis: Final report

    International Nuclear Information System (INIS)

    Schumacher, R.F.

    1993-01-01

    Glass frit will be a major raw material for the operation of the Defense Waste Processing Facility. The frit will be controlled by certificate of conformance and a confirmatory analysis from a commercial analytical laboratory. The following effort provides additional quantitative information on the variability of frit chemical analyses at two commercial laboratories. Identical samples of IDMS Frit 202 were chemically analyzed at two commercial laboratories and at three different times over a period of four months. The SRL-ADS analyses, after correction with the reference standard and normalization, provided confirmatory information, but did not detect the low silica level in one of the frit samples. A methodology utilizing elliptical limits for confirming the certificate of conformance or confirmatory analysis was introduced and recommended for use when the analysis values are close but not within the specification limits. It was also suggested that the lithia specification limits might be reduced as long as CELS is used to confirm the analysis

  15. Sensitivity analysis of periodic errors in heterodyne interferometry

    International Nuclear Information System (INIS)

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-01-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors

  16. Sensitivity analysis of periodic errors in heterodyne interferometry

    Science.gov (United States)

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-03-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors.

  17. Analysis of Employee's Survey for Preventing Human-Errors

    International Nuclear Information System (INIS)

    Sung, Chanho; Kim, Younggab; Joung, Sanghoun

    2013-01-01

    Human errors in nuclear power plant can cause large and small events or incidents. These events or incidents are one of main contributors of reactor trip and might threaten the safety of nuclear plants. To prevent human-errors, KHNP(nuclear power plants) introduced 'Human-error prevention techniques' and have applied the techniques to main parts such as plant operation, operation support, and maintenance and engineering. This paper proposes the methods to prevent and reduce human-errors in nuclear power plants through analyzing survey results which includes the utilization of the human-error prevention techniques and the employees' awareness of preventing human-errors. With regard to human-error prevention, this survey analysis presented the status of the human-error prevention techniques and the employees' awareness of preventing human-errors. Employees' understanding and utilization of the techniques was generally high and training level of employee and training effect on actual works were in good condition. Also, employees answered that the root causes of human-error were due to working environment including tight process, manpower shortage, and excessive mission rather than personal negligence or lack of personal knowledge. Consideration of working environment is certainly needed. At the present time, based on analyzing this survey, the best methods of preventing human-error are personal equipment, training/education substantiality, private mental health check before starting work, prohibit of multiple task performing, compliance with procedures, and enhancement of job site review. However, the most important and basic things for preventing human-error are interests of workers and organizational atmosphere such as communication between managers and workers, and communication between employees and bosses

  18. Attitude Determination Error Analysis System (ADEAS) mathematical specifications document

    Science.gov (United States)

    Nicholson, Mark; Markley, F.; Seidewitz, E.

    1988-01-01

    The mathematical specifications of Release 4.0 of the Attitude Determination Error Analysis System (ADEAS), which provides a general-purpose linear error analysis capability for various spacecraft attitude geometries and determination processes, are presented. The analytical basis of the system is presented. The analytical basis of the system is presented, and detailed equations are provided for both three-axis-stabilized and spin-stabilized attitude sensor models.

  19. Comprehensive analysis of a medication dosing error related to CPOE.

    Science.gov (United States)

    Horsky, Jan; Kuperman, Gilad J; Patel, Vimla L

    2005-01-01

    This case study of a serious medication error demonstrates the necessity of a comprehensive methodology for the analysis of failures in interaction between humans and information systems. The authors used a novel approach to analyze a dosing error related to computer-based ordering of potassium chloride (KCl). The method included a chronological reconstruction of events and their interdependencies from provider order entry usage logs, semistructured interviews with involved clinicians, and interface usability inspection of the ordering system. Information collected from all sources was compared and evaluated to understand how the error evolved and propagated through the system. In this case, the error was the product of faults in interaction among human and system agents that methods limited in scope to their distinct analytical domains would not identify. The authors characterized errors in several converging aspects of the drug ordering process: confusing on-screen laboratory results review, system usability difficulties, user training problems, and suboptimal clinical system safeguards that all contributed to a serious dosing error. The results of the authors' analysis were used to formulate specific recommendations for interface layout and functionality modifications, suggest new user alerts, propose changes to user training, and address error-prone steps of the KCl ordering process to reduce the risk of future medication dosing errors.

  20. Data Analysis & Statistical Methods for Command File Errors

    Science.gov (United States)

    Meshkat, Leila; Waggoner, Bruce; Bryant, Larry

    2014-01-01

    This paper explains current work on modeling for managing the risk of command file errors. It is focused on analyzing actual data from a JPL spaceflight mission to build models for evaluating and predicting error rates as a function of several key variables. We constructed a rich dataset by considering the number of errors, the number of files radiated, including the number commands and blocks in each file, as well as subjective estimates of workload and operational novelty. We have assessed these data using different curve fitting and distribution fitting techniques, such as multiple regression analysis, and maximum likelihood estimation to see how much of the variability in the error rates can be explained with these. We have also used goodness of fit testing strategies and principal component analysis to further assess our data. Finally, we constructed a model of expected error rates based on the what these statistics bore out as critical drivers to the error rate. This model allows project management to evaluate the error rate against a theoretically expected rate as well as anticipate future error rates.

  1. Grinding Method and Error Analysis of Eccentric Shaft Parts

    Science.gov (United States)

    Wang, Zhiming; Han, Qiushi; Li, Qiguang; Peng, Baoying; Li, Weihua

    2017-12-01

    RV reducer and various mechanical transmission parts are widely used in eccentric shaft parts, The demand of precision grinding technology for eccentric shaft parts now, In this paper, the model of X-C linkage relation of eccentric shaft grinding is studied; By inversion method, the contour curve of the wheel envelope is deduced, and the distance from the center of eccentric circle is constant. The simulation software of eccentric shaft grinding is developed, the correctness of the model is proved, the influence of the X-axis feed error, the C-axis feed error and the wheel radius error on the grinding process is analyzed, and the corresponding error calculation model is proposed. The simulation analysis is carried out to provide the basis for the contour error compensation.

  2. An Analysis of Medication Errors at the Military Medical Center: Implications for a Systems Approach for Error Reduction

    National Research Council Canada - National Science Library

    Scheirman, Katherine

    2001-01-01

    An analysis was accomplished of all inpatient medication errors at a military academic medical center during the year 2000, based on the causes of medication errors as described by current research in the field...

  3. Reliability and error analysis on xenon/CT CBF

    International Nuclear Information System (INIS)

    Zhang, Z.

    2000-01-01

    This article provides a quantitative error analysis of a simulation model of xenon/CT CBF in order to investigate the behavior and effect of different types of errors such as CT noise, motion artifacts, lower percentage of xenon supply, lower tissue enhancements, etc. A mathematical model is built to simulate these errors. By adjusting the initial parameters of the simulation model, we can scale the Gaussian noise, control the percentage of xenon supply, and change the tissue enhancement with different kVp settings. The motion artifact will be treated separately by geometrically shifting the sequential CT images. The input function is chosen from an end-tidal xenon curve of a practical study. Four kinds of cerebral blood flow, 10, 20, 50, and 80 cc/100 g/min, are examined under different error environments and the corresponding CT images are generated following the currently popular timing protocol. The simulated studies will be fed to a regular xenon/CT CBF system for calculation and evaluation. A quantitative comparison is given to reveal the behavior and effect of individual error resources. Mixed error testing is also provided to inspect the combination effect of errors. The experiment shows that CT noise is still a major error resource. The motion artifact affects the CBF results more geometrically than quantitatively. Lower xenon supply has a lesser effect on the results, but will reduce the signal/noise ratio. The lower xenon enhancement will lower the flow values in all areas of brain. (author)

  4. Ionospheric error analysis in gps measurements

    Directory of Open Access Journals (Sweden)

    G. Pugliano

    2008-06-01

    Full Text Available The results of an experiment aimed at evaluating the effects of the ionosphere on GPS positioning applications are presented in this paper. Specifically, the study, based upon a differential approach, was conducted utilizing GPS measurements acquired by various receivers located at increasing inter-distances. The experimental research was developed upon the basis of two groups of baselines: the first group is comprised of "short" baselines (less than 10 km; the second group is characterized by greater distances (up to 90 km. The obtained results were compared either upon the basis of the geometric characteristics, for six different baseline lengths, using 24 hours of data, or upon temporal variations, by examining two periods of varying intensity in ionospheric activity respectively coinciding with the maximum of the 23 solar cycle and in conditions of low ionospheric activity. The analysis revealed variations in terms of inter-distance as well as different performances primarily owing to temporal modifications in the state of the ionosphere.

  5. Compensation for geometric modeling errors by positioning of electrodes in electrical impedance tomography

    DEFF Research Database (Denmark)

    Hyvönen, N.; Majander, H.; Staboulis, Stratos

    2017-01-01

    Electrical impedance tomography aims at reconstructing the conductivity inside a physical body from boundary measurements of current and voltage at a finite number of contact electrodes. In many practical applications, the shape of the imaged object is subject to considerable uncertainties...

  6. Formal Analysis of Soft Errors using Theorem Proving

    Directory of Open Access Journals (Sweden)

    Sofiène Tahar

    2013-07-01

    Full Text Available Modeling and analysis of soft errors in electronic circuits has traditionally been done using computer simulations. Computer simulations cannot guarantee correctness of analysis because they utilize approximate real number representations and pseudo random numbers in the analysis and thus are not well suited for analyzing safety-critical applications. In this paper, we present a higher-order logic theorem proving based method for modeling and analysis of soft errors in electronic circuits. Our developed infrastructure includes formalized continuous random variable pairs, their Cumulative Distribution Function (CDF properties and independent standard uniform and Gaussian random variables. We illustrate the usefulness of our approach by modeling and analyzing soft errors in commonly used dynamic random access memory sense amplifier circuits.

  7. Multiobjective optimization framework for landmark measurement error correction in three-dimensional cephalometric tomography.

    Science.gov (United States)

    DeCesare, A; Secanell, M; Lagravère, M O; Carey, J

    2013-01-01

    The purpose of this study is to minimize errors that occur when using a four vs six landmark superimpositioning method in the cranial base to define the co-ordinate system. Cone beam CT volumetric data from ten patients were used for this study. Co-ordinate system transformations were performed. A co-ordinate system was constructed using two planes defined by four anatomical landmarks located by an orthodontist. A second co-ordinate system was constructed using four anatomical landmarks that are corrected using a numerical optimization algorithm for any landmark location operator error using information from six landmarks. The optimization algorithm minimizes the relative distance and angle between the known fixed points in the two images to find the correction. Measurement errors and co-ordinates in all axes were obtained for each co-ordinate system. Significant improvement is observed after using the landmark correction algorithm to position the final co-ordinate system. The errors found in a previous study are significantly reduced. Errors found were between 1 mm and 2 mm. When analysing real patient data, it was found that the 6-point correction algorithm reduced errors between images and increased intrapoint reliability. A novel method of optimizing the overlay of three-dimensional images using a 6-point correction algorithm was introduced and examined. This method demonstrated greater reliability and reproducibility than the previous 4-point correction algorithm.

  8. QUALITATIVE DATA AND ERROR MEASUREMENT IN INPUT-OUTPUT-ANALYSIS

    NARCIS (Netherlands)

    NIJKAMP, P; OOSTERHAVEN, J; OUWERSLOOT, H; RIETVELD, P

    1992-01-01

    This paper is a contribution to the rapidly emerging field of qualitative data analysis in economics. Ordinal data techniques and error measurement in input-output analysis are here combined in order to test the reliability of a low level of measurement and precision of data by means of a stochastic

  9. Understanding Teamwork in Trauma Resuscitation through Analysis of Team Errors

    Science.gov (United States)

    Sarcevic, Aleksandra

    2009-01-01

    An analysis of human errors in complex work settings can lead to important insights into the workspace design. This type of analysis is particularly relevant to safety-critical, socio-technical systems that are highly dynamic, stressful and time-constrained, and where failures can result in catastrophic societal, economic or environmental…

  10. SHEAN (Simplified Human Error Analysis code) and automated THERP

    International Nuclear Information System (INIS)

    Wilson, J.R.

    1993-01-01

    One of the most widely used human error analysis tools is THERP (Technique for Human Error Rate Prediction). Unfortunately, this tool has disadvantages. The Nuclear Regulatory Commission, realizing these drawbacks, commissioned Dr. Swain, the author of THERP, to create a simpler, more consistent tool for deriving human error rates. That effort produced the Accident Sequence Evaluation Program Human Reliability Analysis Procedure (ASEP), which is more conservative than THERP, but a valuable screening tool. ASEP involves answering simple questions about the scenario in question, and then looking up the appropriate human error rate in the indicated table (THERP also uses look-up tables, but four times as many). The advantages of ASEP are that human factors expertise is not required, and the training to use the method is minimal. Although not originally envisioned by Dr. Swain, the ASEP approach actually begs to be computerized. That WINCO did, calling the code SHEAN, for Simplified Human Error ANalysis. The code was done in TURBO Basic for IBM or IBM-compatible MS-DOS, for fast execution. WINCO is now in the process of comparing this code against THERP for various scenarios. This report provides a discussion of SHEAN

  11. Applications of human error analysis to aviation and space operations

    International Nuclear Information System (INIS)

    Nelson, W.R.

    1998-01-01

    For the past several years at the Idaho National Engineering and Environmental Laboratory (INEEL) we have been working to apply methods of human error analysis to the design of complex systems. We have focused on adapting human reliability analysis (HRA) methods that were developed for Probabilistic Safety Assessment (PSA) for application to system design. We are developing methods so that human errors can be systematically identified during system design, the potential consequences of each error can be assessed, and potential corrective actions (e.g. changes to system design or procedures) can be identified. These applications lead to different requirements when compared with HR.As performed as part of a PSA. For example, because the analysis will begin early during the design stage, the methods must be usable when only partial design information is available. In addition, the ability to perform numerous ''what if'' analyses to identify and compare multiple design alternatives is essential. Finally, since the goals of such human error analyses focus on proactive design changes rather than the estimate of failure probabilities for PRA, there is more emphasis on qualitative evaluations of error relationships and causal factors than on quantitative estimates of error frequency. The primary vehicle we have used to develop and apply these methods has been a series of prqjects sponsored by the National Aeronautics and Space Administration (NASA) to apply human error analysis to aviation operations. The first NASA-sponsored project had the goal to evaluate human errors caused by advanced cockpit automation. Our next aviation project focused on the development of methods and tools to apply human error analysis to the design of commercial aircraft. This project was performed by a consortium comprised of INEEL, NASA, and Boeing Commercial Airplane Group. The focus of the project was aircraft design and procedures that could lead to human errors during airplane maintenance

  12. Error analysis for mesospheric temperature profiling by absorptive occultation sensors

    Directory of Open Access Journals (Sweden)

    M. J. Rieder

    Full Text Available An error analysis for mesospheric profiles retrieved from absorptive occultation data has been performed, starting with realistic error assumptions as would apply to intensity data collected by available high-precision UV photodiode sensors. Propagation of statistical errors was investigated through the complete retrieval chain from measured intensity profiles to atmospheric density, pressure, and temperature profiles. We assumed unbiased errors as the occultation method is essentially self-calibrating and straight-line propagation of occulted signals as we focus on heights of 50–100 km, where refractive bending of the sensed radiation is negligible. Throughout the analysis the errors were characterized at each retrieval step by their mean profile, their covariance matrix and their probability density function (pdf. This furnishes, compared to a variance-only estimation, a much improved insight into the error propagation mechanism. We applied the procedure to a baseline analysis of the performance of a recently proposed solar UV occultation sensor (SMAS – Sun Monitor and Atmospheric Sounder and provide, using a reasonable exponential atmospheric model as background, results on error standard deviations and error correlation functions of density, pressure, and temperature profiles. Two different sensor photodiode assumptions are discussed, respectively, diamond diodes (DD with 0.03% and silicon diodes (SD with 0.1% (unattenuated intensity measurement noise at 10 Hz sampling rate. A factor-of-2 margin was applied to these noise values in order to roughly account for unmodeled cross section uncertainties. Within the entire height domain (50–100 km we find temperature to be retrieved to better than 0.3 K (DD / 1 K (SD accuracy, respectively, at 2 km height resolution. The results indicate that absorptive occultations acquired by a SMAS-type sensor could provide mesospheric profiles of fundamental variables such as temperature with

  13. Error analysis for mesospheric temperature profiling by absorptive occultation sensors

    Directory of Open Access Journals (Sweden)

    M. J. Rieder

    2001-01-01

    Full Text Available An error analysis for mesospheric profiles retrieved from absorptive occultation data has been performed, starting with realistic error assumptions as would apply to intensity data collected by available high-precision UV photodiode sensors. Propagation of statistical errors was investigated through the complete retrieval chain from measured intensity profiles to atmospheric density, pressure, and temperature profiles. We assumed unbiased errors as the occultation method is essentially self-calibrating and straight-line propagation of occulted signals as we focus on heights of 50–100 km, where refractive bending of the sensed radiation is negligible. Throughout the analysis the errors were characterized at each retrieval step by their mean profile, their covariance matrix and their probability density function (pdf. This furnishes, compared to a variance-only estimation, a much improved insight into the error propagation mechanism. We applied the procedure to a baseline analysis of the performance of a recently proposed solar UV occultation sensor (SMAS – Sun Monitor and Atmospheric Sounder and provide, using a reasonable exponential atmospheric model as background, results on error standard deviations and error correlation functions of density, pressure, and temperature profiles. Two different sensor photodiode assumptions are discussed, respectively, diamond diodes (DD with 0.03% and silicon diodes (SD with 0.1% (unattenuated intensity measurement noise at 10 Hz sampling rate. A factor-of-2 margin was applied to these noise values in order to roughly account for unmodeled cross section uncertainties. Within the entire height domain (50–100 km we find temperature to be retrieved to better than 0.3 K (DD / 1 K (SD accuracy, respectively, at 2 km height resolution. The results indicate that absorptive occultations acquired by a SMAS-type sensor could provide mesospheric profiles of fundamental variables such as temperature with

  14. Image enhancement by spectral-error correction for dual-energy computed tomography.

    Science.gov (United States)

    Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

    2011-01-01

    Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

  15. The use of ionospheric tomography and elevation masks to reduce the overall error in single-frequency GPS timing applications

    Science.gov (United States)

    Rose, Julian A. R.; Tong, Jenna R.; Allain, Damien J.; Mitchell, Cathryn N.

    2011-01-01

    Signals from Global Positioning System (GPS) satellites at the horizon or at low elevations are often excluded from a GPS solution because they experience considerable ionospheric delays and multipath effects. Their exclusion can degrade the overall satellite geometry for the calculations, resulting in greater errors; an effect known as the Dilution of Precision (DOP). In contrast, signals from high elevation satellites experience less ionospheric delays and multipath effects. The aim is to find a balance in the choice of elevation mask, to reduce the propagation delays and multipath whilst maintaining good satellite geometry, and to use tomography to correct for the ionosphere and thus improve single-frequency GPS timing accuracy. GPS data, collected from a global network of dual-frequency GPS receivers, have been used to produce four GPS timing solutions, each with a different ionospheric compensation technique. One solution uses a 4D tomographic algorithm, Multi-Instrument Data Analysis System (MIDAS), to compensate for the ionospheric delay. Maps of ionospheric electron density are produced and used to correct the single-frequency pseudorange observations. This method is compared to a dual-frequency solution and two other single-frequency solutions: one does not include any ionospheric compensation and the other uses the broadcast Klobuchar model. Data from the solar maximum year 2002 and October 2003 have been investigated to display results when the ionospheric delays are large and variable. The study focuses on Europe and results are produced for the chosen test site, VILL (Villafranca, Spain). The effects of excluding all of the GPS satellites below various elevation masks, ranging from 5° to 40°, on timing solutions for fixed (static) and mobile (moving) situations are presented. The greatest timing accuracies when using the fixed GPS receiver technique are obtained by using a 40° mask, rather than a 5° mask. The mobile GPS timing solutions are most

  16. Error Analysis Of Clock Time (T), Declination (*) And Latitude ...

    African Journals Online (AJOL)

    ), latitude (Φ), longitude (λ) and azimuth (A); which are aimed at establishing fixed positions and orientations of survey points and lines on the earth surface. The paper attempts the analysis of the individual and combined effects of error in time ...

  17. Analysis of possible systematic errors in the Oslo method

    International Nuclear Information System (INIS)

    Larsen, A. C.; Guttormsen, M.; Buerger, A.; Goergen, A.; Nyhus, H. T.; Rekstad, J.; Siem, S.; Toft, H. K.; Tveten, G. M.; Wikan, K.; Krticka, M.; Betak, E.; Schiller, A.; Voinov, A. V.

    2011-01-01

    In this work, we have reviewed the Oslo method, which enables the simultaneous extraction of the level density and γ-ray transmission coefficient from a set of particle-γ coincidence data. Possible errors and uncertainties have been investigated. Typical data sets from various mass regions as well as simulated data have been tested against the assumptions behind the data analysis.

  18. Technical Note: Introduction of variance component analysis to setup error analysis in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, Yukinori, E-mail: ymatsuo@kuhp.kyoto-u.ac.jp; Nakamura, Mitsuhiro; Mizowaki, Takashi; Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo, Kyoto 606-8507 (Japan)

    2016-09-15

    Purpose: The purpose of this technical note is to introduce variance component analysis to the estimation of systematic and random components in setup error of radiotherapy. Methods: Balanced data according to the one-factor random effect model were assumed. Results: Analysis-of-variance (ANOVA)-based computation was applied to estimate the values and their confidence intervals (CIs) for systematic and random errors and the population mean of setup errors. The conventional method overestimates systematic error, especially in hypofractionated settings. The CI for systematic error becomes much wider than that for random error. The ANOVA-based estimation can be extended to a multifactor model considering multiple causes of setup errors (e.g., interpatient, interfraction, and intrafraction). Conclusions: Variance component analysis may lead to novel applications to setup error analysis in radiotherapy.

  19. Technical Note: Introduction of variance component analysis to setup error analysis in radiotherapy

    International Nuclear Information System (INIS)

    Matsuo, Yukinori; Nakamura, Mitsuhiro; Mizowaki, Takashi; Hiraoka, Masahiro

    2016-01-01

    Purpose: The purpose of this technical note is to introduce variance component analysis to the estimation of systematic and random components in setup error of radiotherapy. Methods: Balanced data according to the one-factor random effect model were assumed. Results: Analysis-of-variance (ANOVA)-based computation was applied to estimate the values and their confidence intervals (CIs) for systematic and random errors and the population mean of setup errors. The conventional method overestimates systematic error, especially in hypofractionated settings. The CI for systematic error becomes much wider than that for random error. The ANOVA-based estimation can be extended to a multifactor model considering multiple causes of setup errors (e.g., interpatient, interfraction, and intrafraction). Conclusions: Variance component analysis may lead to novel applications to setup error analysis in radiotherapy.

  20. Detecting errors in micro and trace analysis by using statistics

    DEFF Research Database (Denmark)

    Heydorn, K.

    1993-01-01

    By assigning a standard deviation to each step in an analytical method it is possible to predict the standard deviation of each analytical result obtained by this method. If the actual variability of replicate analytical results agrees with the expected, the analytical method is said...... to be in statistical control. Significant deviations between analytical results from different laboratories reveal the presence of systematic errors, and agreement between different laboratories indicate the absence of systematic errors. This statistical approach, referred to as the analysis of precision, was applied...

  1. Determining Bounds on Assumption Errors in Operational Analysis

    Directory of Open Access Journals (Sweden)

    Neal M. Bengtson

    2014-01-01

    Full Text Available The technique of operational analysis (OA is used in the study of systems performance, mainly for estimating mean values of various measures of interest, such as, number of jobs at a device and response times. The basic principles of operational analysis allow errors in assumptions to be quantified over a time period. The assumptions which are used to derive the operational analysis relationships are studied. Using Karush-Kuhn-Tucker (KKT conditions bounds on error measures of these OA relationships are found. Examples of these bounds are used for representative performance measures to show limits on the difference between true performance values and those estimated by operational analysis relationships. A technique for finding tolerance limits on the bounds is demonstrated with a simulation example.

  2. Interactive analysis of human error factors in NPP operation events

    International Nuclear Information System (INIS)

    Zhang Li; Zou Yanhua; Huang Weigang

    2010-01-01

    Interactive of human error factors in NPP operation events were introduced, and 645 WANO operation event reports from 1999 to 2008 were analyzed, among which 432 were found relative to human errors. After classifying these errors with the Root Causes or Causal Factors, and then applying SPSS for correlation analysis,we concluded: (1) Personnel work practices are restricted by many factors. Forming a good personnel work practices is a systematic work which need supports in many aspects. (2)Verbal communications,personnel work practices, man-machine interface and written procedures and documents play great roles. They are four interaction factors which often come in bundle. If some improvements need to be made on one of them,synchronous measures are also necessary for the others.(3) Management direction and decision process, which are related to management,have a significant interaction with personnel factors. (authors)

  3. Predicting positional error of MLC using volumetric analysis

    International Nuclear Information System (INIS)

    Hareram, E.S.

    2008-01-01

    IMRT normally using multiple beamlets (small width of the beam) for a particular field to deliver so that it is imperative to maintain the positional accuracy of the MLC in order to deliver integrated computed dose accurately. Different manufacturers have reported high precession on MLC devices with leaf positional accuracy nearing 0.1 mm but measuring and rectifying the error in this accuracy is very difficult. Various methods are used to check MLC position and among this volumetric analysis is one of the technique. Volumetric approach was adapted in our method using primus machine and 0.6cc chamber at 5 cm depth In perspex. MLC of 1 mm error introduces an error of 20%, more sensitive to other methods

  4. An Error Analysis of Structured Light Scanning of Biological Tissue

    DEFF Research Database (Denmark)

    Jensen, Sebastian Hoppe Nesgaard; Wilm, Jakob; Aanæs, Henrik

    2017-01-01

    This paper presents an error analysis and correction model for four structured light methods applied to three common types of biological tissue; skin, fat and muscle. Despite its many advantages, structured light is based on the assumption of direct reflection at the object surface only......, statistical linear model based on the scan geometry. As such, scans can be corrected without introducing any specially designed pattern strategy or hardware. We can effectively reduce the error in a structured light scanner applied to biological tissue by as much as factor of two or three........ This assumption is violated by most biological material e.g. human skin, which exhibits subsurface scattering. In this study, we find that in general, structured light scans of biological tissue deviate significantly from the ground truth. We show that a large portion of this error can be predicted with a simple...

  5. Students’ Written Production Error Analysis in the EFL Classroom Teaching: A Study of Adult English Learners Errors

    Directory of Open Access Journals (Sweden)

    Ranauli Sihombing

    2016-12-01

    Full Text Available Errors analysis has become one of the most interesting issues in the study of Second Language Acquisition. It can not be denied that some teachers do not know a lot about error analysis and related theories of how L1, L2 or foreign language acquired. In addition, the students often feel upset since they find a gap between themselves and the teachers for the errors the students make and the teachers’ understanding about the error correction. The present research aims to investigate what errors adult English learners make in written production of English. The significances of the study is to know what errors students make in writing that the teachers can find solution to the errors the students make for a better English language teaching and learning especially in teaching English for adults. The study employed qualitative method. The research was undertaken at an airline education center in Bandung. The result showed that syntax errors are more frequently found than morphology errors, especially in terms of verb phrase errors. It is recommended that it is important for teacher to know the theory of second language acquisition in order to know how the students learn and produce theirlanguage. In addition, it will be advantages for teachers if they know what errors students frequently make in their learning, so that the teachers can give solution to the students for a better English language learning achievement.   DOI: https://doi.org/10.24071/llt.2015.180205

  6. Critical slowing down and error analysis in lattice QCD simulations

    International Nuclear Information System (INIS)

    Virotta, Francesco

    2012-01-01

    In this work we investigate the critical slowing down of lattice QCD simulations. We perform a preliminary study in the quenched approximation where we find that our estimate of the exponential auto-correlation time scales as τ exp (a)∝a -5 , where a is the lattice spacing. In unquenched simulations with O(a) improved Wilson fermions we do not obtain a scaling law but find results compatible with the behavior that we find in the pure gauge theory. The discussion is supported by a large set of ensembles both in pure gauge and in the theory with two degenerate sea quarks. We have moreover investigated the effect of slow algorithmic modes in the error analysis of the expectation value of typical lattice QCD observables (hadronic matrix elements and masses). In the context of simulations affected by slow modes we propose and test a method to obtain reliable estimates of statistical errors. The method is supposed to help in the typical algorithmic setup of lattice QCD, namely when the total statistics collected is of O(10)τ exp . This is the typical case when simulating close to the continuum limit where the computational costs for producing two independent data points can be extremely large. We finally discuss the scale setting in N f =2 simulations using the Kaon decay constant f K as physical input. The method is explained together with a thorough discussion of the error analysis employed. A description of the publicly available code used for the error analysis is included.

  7. Compensation for geometric modeling errors by positioning of electrodes in electrical impedance tomography

    International Nuclear Information System (INIS)

    Hyvönen, N; Majander, H; Staboulis, S

    2017-01-01

    Electrical impedance tomography aims at reconstructing the conductivity inside a physical body from boundary measurements of current and voltage at a finite number of contact electrodes. In many practical applications, the shape of the imaged object is subject to considerable uncertainties that render reconstructing the internal conductivity impossible if they are not taken into account. This work numerically demonstrates that one can compensate for inaccurate modeling of the object boundary in two spatial dimensions by finding compatible locations and sizes for the electrodes as a part of a reconstruction algorithm. The numerical studies, which are based on both simulated and experimental data, are complemented by proving that the employed complete electrode model is approximately conformally invariant, which suggests that the obtained reconstructions in mismodeled domains reflect conformal images of the true targets. The numerical experiments also confirm that a similar approach does not, in general, lead to a functional algorithm in three dimensions. (paper)

  8. Analysis of airways in computed tomography

    DEFF Research Database (Denmark)

    Petersen, Jens

    Chronic Obstructive Pulmonary Disease (COPD) is major cause of death and disability world-wide. It affects lung function through destruction of lung tissue known as emphysema and inflammation of airways, leading to thickened airway walls and narrowed airway lumen. Computed Tomography (CT) imaging...

  9. Potential Measurement Errors Due to Image Enlargement in Optical Coherence Tomography Imaging

    Science.gov (United States)

    Uji, Akihito; Murakami, Tomoaki; Muraoka, Yuki; Hosoda, Yoshikatsu; Yoshitake, Shin; Dodo, Yoko; Arichika, Shigeta; Yoshimura, Nagahisa

    2015-01-01

    The effect of interpolation and super-resolution (SR) algorithms on quantitative and qualitative assessments of enlarged optical coherence tomography (OCT) images was investigated in this report. Spectral-domain OCT images from 30 eyes in 30 consecutive patients with diabetic macular edema (DME) and 20 healthy eyes in 20 consecutive volunteers were analyzed. Original image (OR) resolution was reduced by a factor of four. Images were then magnified by a factor of four with and without application of one of the following algorithms: bilinear (BL), bicubic (BC), Lanczos3 (LA), and SR. Differences in peak signal-to-noise ratio (PSNR), retinal nerve fiber layer (RNFL) thickness, photoreceptor layer status, and parallelism (reflects the complexity of photoreceptor layer alterations) were analyzed in each image type. The order of PSNRs from highest to lowest was SR > LA > BC > BL > non-processed enlarged images (NONE). The PSNR was statistically different in all groups. The NONE, BC, and LA images resulted in significantly thicker RNFL measurements than the OR image. In eyes with DME, the photoreceptor layer, which was hardly identifiable in NONE images, became detectable with algorithm application. However, OCT photoreceptor parameters were still assessed as more undetectable than in OR images. Parallelism was not statistically different in OR and NONE images, but other image groups had significantly higher parallelism than OR images. Our results indicated that interpolation and SR algorithms increased OCT image resolution. However, qualitative and quantitative assessments were influenced by algorithm use. Additionally, each algorithm affected the assessments differently. PMID:26024236

  10. Accommodating error analysis in comparison and clustering of molecular fingerprints.

    OpenAIRE

    Salamon, H.; Segal, M. R.; Ponce de Leon, A.; Small, P. M.

    1998-01-01

    Molecular epidemiologic studies of infectious diseases rely on pathogen genotype comparisons, which usually yield patterns comprising sets of DNA fragments (DNA fingerprints). We use a highly developed genotyping system, IS6110-based restriction fragment length polymorphism analysis of Mycobacterium tuberculosis, to develop a computational method that automates comparison of large numbers of fingerprints. Because error in fragment length measurements is proportional to fragment length and is ...

  11. Radiological error: analysis, standard setting, targeted instruction and teamworking

    International Nuclear Information System (INIS)

    FitzGerald, Richard

    2005-01-01

    Diagnostic radiology does not have objective benchmarks for acceptable levels of missed diagnoses [1]. Until now, data collection of radiological discrepancies has been very time consuming. The culture within the specialty did not encourage it. However, public concern about patient safety is increasing. There have been recent innovations in compiling radiological interpretive discrepancy rates which may facilitate radiological standard setting. However standard setting alone will not optimise radiologists' performance or patient safety. We must use these new techniques in radiological discrepancy detection to stimulate greater knowledge sharing, targeted instruction and teamworking among radiologists. Not all radiological discrepancies are errors. Radiological discrepancy programmes must not be abused as an instrument for discrediting individual radiologists. Discrepancy rates must not be distorted as a weapon in turf battles. Radiological errors may be due to many causes and are often multifactorial. A systems approach to radiological error is required. Meaningful analysis of radiological discrepancies and errors is challenging. Valid standard setting will take time. Meanwhile, we need to develop top-up training, mentoring and rehabilitation programmes. (orig.)

  12. Analysis of the computed tomography in the acute abdomen

    International Nuclear Information System (INIS)

    Hochhegger, Bruno; Moraes, Everton; Haygert, Carlos Jesus Pereira; Antunes, Paulo Sergio Pase; Gazzoni, Fernando; Lopes, Luis Felipe Dias

    2007-01-01

    Introduction: This study tends to test the capacity of the computed tomography in assist in the diagnosis and the approach of the acute abdomen. Material and method: This is a longitudinal and prospective study, in which were analyzed the patients with the diagnosis of acute abdomen. There were obtained 105 cases of acute abdomen and after the application of the exclusions criteria were included 28 patients in the study. Results: Computed tomography changed the diagnostic hypothesis of the physicians in 50% of the cases (p 0.05), where 78.57% of the patients had surgical indication before computed tomography and 67.86% after computed tomography (p = 0.0546). The index of accurate diagnosis of computed tomography, when compared to the anatomopathologic examination and the final diagnosis, was observed in 82.14% of the cases (p = 0.013). When the analysis was done dividing the patients in surgical and nonsurgical group, were obtained an accuracy of 89.28% (p 0.0001). The difference of 7.2 days of hospitalization (p = 0.003) was obtained compared with the mean of the acute abdomen without use the computed tomography. Conclusion: The computed tomography is correlative with the anatomopathology and has great accuracy in the surgical indication, associated with the capacity of increase the confident index of the physicians, reduces the hospitalization time, reduces the number of surgeries and is cost-effective. (author)

  13. Elemental analysis of hair using PIXE-tomography and INAA

    International Nuclear Information System (INIS)

    Beasley, D.; Gomez-Morilla, I.; Spyrou, N.

    2008-01-01

    3D quantitative elemental maps of a section of a strand of hair were produced using a combination of PIXE-Tomography and simultaneous On/Off Axis STIM-Tomography at the University of Surrey Ion Beam Centre. The distributions of S, K, Cl, Ca, Fe and Zn were determined using the PIXE-T reconstruction package DISRA. The results were compared with conventional bulk PIXE analysis of tomographic data as determined using Dan32. The overall concentrations determined by PIXE were compared with elemental concentrations held in the University of Surrey Hair Database. All the entries currently in the database were produced using INAA. The merits and possible contributions of tomographic PIXE analysis to analysis of hair are discussed. The conclusions drawn from the PIXE-Tomography analysis can be used to argue for more stringent procedures for hair analysis at the University of Surrey. (author)

  14. Critical slowing down and error analysis in lattice QCD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Virotta, Francesco

    2012-02-21

    In this work we investigate the critical slowing down of lattice QCD simulations. We perform a preliminary study in the quenched approximation where we find that our estimate of the exponential auto-correlation time scales as {tau}{sub exp}(a){proportional_to}a{sup -5}, where a is the lattice spacing. In unquenched simulations with O(a) improved Wilson fermions we do not obtain a scaling law but find results compatible with the behavior that we find in the pure gauge theory. The discussion is supported by a large set of ensembles both in pure gauge and in the theory with two degenerate sea quarks. We have moreover investigated the effect of slow algorithmic modes in the error analysis of the expectation value of typical lattice QCD observables (hadronic matrix elements and masses). In the context of simulations affected by slow modes we propose and test a method to obtain reliable estimates of statistical errors. The method is supposed to help in the typical algorithmic setup of lattice QCD, namely when the total statistics collected is of O(10){tau}{sub exp}. This is the typical case when simulating close to the continuum limit where the computational costs for producing two independent data points can be extremely large. We finally discuss the scale setting in N{sub f}=2 simulations using the Kaon decay constant f{sub K} as physical input. The method is explained together with a thorough discussion of the error analysis employed. A description of the publicly available code used for the error analysis is included.

  15. Tomography

    International Nuclear Information System (INIS)

    1985-01-01

    Already widely accepted in medicine, tomography can also be useful in industry. The theory behind tomography and a demonstration of the technique to inspect a motorcycle carburetor is presented. To demonstrate the potential of computer assisted tomography (CAT) to accurately locate defects in three dimensions, a sectioned 5 cm gate valve with a shrink cavity made visible by the sectioning was tomographically imaged using a Co-60 source. The tomographic images revealed a larger cavity below the sectioned surface. The position of this cavity was located with an in-plane and axial precision of approximately +-1 mm. The volume of the cavity was estimated to be approximately 40 mm 3

  16. Error analysis of short term wind power prediction models

    International Nuclear Information System (INIS)

    De Giorgi, Maria Grazia; Ficarella, Antonio; Tarantino, Marco

    2011-01-01

    The integration of wind farms in power networks has become an important problem. This is because the electricity produced cannot be preserved because of the high cost of storage and electricity production must follow market demand. Short-long-range wind forecasting over different lengths/periods of time is becoming an important process for the management of wind farms. Time series modelling of wind speeds is based upon the valid assumption that all the causative factors are implicitly accounted for in the sequence of occurrence of the process itself. Hence time series modelling is equivalent to physical modelling. Auto Regressive Moving Average (ARMA) models, which perform a linear mapping between inputs and outputs, and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS), which perform a non-linear mapping, provide a robust approach to wind power prediction. In this work, these models are developed in order to forecast power production of a wind farm with three wind turbines, using real load data and comparing different time prediction periods. This comparative analysis takes in the first time, various forecasting methods, time horizons and a deep performance analysis focused upon the normalised mean error and the statistical distribution hereof in order to evaluate error distribution within a narrower curve and therefore forecasting methods whereby it is more improbable to make errors in prediction. (author)

  17. Error analysis of short term wind power prediction models

    Energy Technology Data Exchange (ETDEWEB)

    De Giorgi, Maria Grazia; Ficarella, Antonio; Tarantino, Marco [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via per Monteroni, 73100 Lecce (Italy)

    2011-04-15

    The integration of wind farms in power networks has become an important problem. This is because the electricity produced cannot be preserved because of the high cost of storage and electricity production must follow market demand. Short-long-range wind forecasting over different lengths/periods of time is becoming an important process for the management of wind farms. Time series modelling of wind speeds is based upon the valid assumption that all the causative factors are implicitly accounted for in the sequence of occurrence of the process itself. Hence time series modelling is equivalent to physical modelling. Auto Regressive Moving Average (ARMA) models, which perform a linear mapping between inputs and outputs, and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS), which perform a non-linear mapping, provide a robust approach to wind power prediction. In this work, these models are developed in order to forecast power production of a wind farm with three wind turbines, using real load data and comparing different time prediction periods. This comparative analysis takes in the first time, various forecasting methods, time horizons and a deep performance analysis focused upon the normalised mean error and the statistical distribution hereof in order to evaluate error distribution within a narrower curve and therefore forecasting methods whereby it is more improbable to make errors in prediction. (author)

  18. Critical slowing down and error analysis in lattice QCD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Stefan [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Sommer, Rainer; Virotta, Francesco [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2010-09-15

    We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)

  19. Critical slowing down and error analysis in lattice QCD simulations

    International Nuclear Information System (INIS)

    Schaefer, Stefan; Sommer, Rainer; Virotta, Francesco

    2010-09-01

    We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)

  20. Evaluation of Analysis by Cross-Validation, Part II: Diagnostic and Optimization of Analysis Error Covariance

    Directory of Open Access Journals (Sweden)

    Richard Ménard

    2018-02-01

    Full Text Available We present a general theory of estimation of analysis error covariances based on cross-validation as well as a geometric interpretation of the method. In particular, we use the variance of passive observation-minus-analysis residuals and show that the true analysis error variance can be estimated, without relying on the optimality assumption. This approach is used to obtain near optimal analyses that are then used to evaluate the air quality analysis error using several different methods at active and passive observation sites. We compare the estimates according to the method of Hollingsworth-Lönnberg, Desroziers et al., a new diagnostic we developed, and the perceived analysis error computed from the analysis scheme, to conclude that, as long as the analysis is near optimal, all estimates agree within a certain error margin.

  1. Analytical sensitivity analysis of geometric errors in a three axis machine tool

    International Nuclear Information System (INIS)

    Park, Sung Ryung; Yang, Seung Han

    2012-01-01

    In this paper, an analytical method is used to perform a sensitivity analysis of geometric errors in a three axis machine tool. First, an error synthesis model is constructed for evaluating the position volumetric error due to the geometric errors, and then an output variable is defined, such as the magnitude of the position volumetric error. Next, the global sensitivity analysis is executed using an analytical method. Finally, the sensitivity indices are calculated using the quantitative values of the geometric errors

  2. Quantum Tomography via Compressed Sensing: Error Bounds, Sample Complexity and Efficient Estimators (Open Access, Publisher’s Version)

    Science.gov (United States)

    2012-09-27

    ultralong lifetimes and their tomographic state analysis Phys. Rev. Lett. 92 220402 [7] Resch K J, Walther P and Zeilinger A 2005 Full characterization...of a three-photon Greenberger– Horne– Zeilinger state using quantum state tomography Phys. Rev. Lett. 94 070402 [8] Häffner H et al 2005 Scalable...Iterative algorithm for reconstruction of entangled states Phys. Rev. A 63 040303 [74] Molina-Terriza G, Vaziri A, Řeháček J, Hradil Z and Zeilinger

  3. Error performance analysis in downlink cellular networks with interference management

    KAUST Repository

    Afify, Laila H.

    2015-05-01

    Modeling aggregate network interference in cellular networks has recently gained immense attention both in academia and industry. While stochastic geometry based models have succeeded to account for the cellular network geometry, they mostly abstract many important wireless communication system aspects (e.g., modulation techniques, signal recovery techniques). Recently, a novel stochastic geometry model, based on the Equivalent-in-Distribution (EiD) approach, succeeded to capture the aforementioned communication system aspects and extend the analysis to averaged error performance, however, on the expense of increasing the modeling complexity. Inspired by the EiD approach, the analysis developed in [1] takes into consideration the key system parameters, while providing a simple tractable analysis. In this paper, we extend this framework to study the effect of different interference management techniques in downlink cellular network. The accuracy of the proposed analysis is verified via Monte Carlo simulations.

  4. Error Analysis for Fourier Methods for Option Pricing

    KAUST Repository

    Häppölä, Juho

    2016-01-06

    We provide a bound for the error committed when using a Fourier method to price European options when the underlying follows an exponential Levy dynamic. The price of the option is described by a partial integro-differential equation (PIDE). Applying a Fourier transformation to the PIDE yields an ordinary differential equation that can be solved analytically in terms of the characteristic exponent of the Levy process. Then, a numerical inverse Fourier transform allows us to obtain the option price. We present a novel bound for the error and use this bound to set the parameters for the numerical method. We analyze the properties of the bound for a dissipative and pure-jump example. The bound presented is independent of the asymptotic behaviour of option prices at extreme asset prices. The error bound can be decomposed into a product of terms resulting from the dynamics and the option payoff, respectively. The analysis is supplemented by numerical examples that demonstrate results comparable to and superior to the existing literature.

  5. FRamework Assessing Notorious Contributing Influences for Error (FRANCIE): Perspective on Taxonomy Development to Support Error Reporting and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lon N. Haney; David I. Gertman

    2003-04-01

    Beginning in the 1980s a primary focus of human reliability analysis was estimation of human error probabilities. However, detailed qualitative modeling with comprehensive representation of contextual variables often was lacking. This was likely due to the lack of comprehensive error and performance shaping factor taxonomies, and the limited data available on observed error rates and their relationship to specific contextual variables. In the mid 90s Boeing, America West Airlines, NASA Ames Research Center and INEEL partnered in a NASA sponsored Advanced Concepts grant to: assess the state of the art in human error analysis, identify future needs for human error analysis, and develop an approach addressing these needs. Identified needs included the need for a method to identify and prioritize task and contextual characteristics affecting human reliability. Other needs identified included developing comprehensive taxonomies to support detailed qualitative modeling and to structure meaningful data collection efforts across domains. A result was the development of the FRamework Assessing Notorious Contributing Influences for Error (FRANCIE) with a taxonomy for airline maintenance tasks. The assignment of performance shaping factors to generic errors by experts proved to be valuable to qualitative modeling. Performance shaping factors and error types from such detailed approaches can be used to structure error reporting schemes. In a recent NASA Advanced Human Support Technology grant FRANCIE was refined, and two new taxonomies for use on space missions were developed. The development, sharing, and use of error taxonomies, and the refinement of approaches for increased fidelity of qualitative modeling is offered as a means to help direct useful data collection strategies.

  6. Error Analysis of Galerkin's Method for Semilinear Equations

    Directory of Open Access Journals (Sweden)

    Tadashi Kawanago

    2012-01-01

    Full Text Available We establish a general existence result for Galerkin's approximate solutions of abstract semilinear equations and conduct an error analysis. Our results may be regarded as some extension of a precedent work (Schultz 1969. The derivation of our results is, however, different from the discussion in his paper and is essentially based on the convergence theorem of Newton’s method and some techniques for deriving it. Some of our results may be applicable for investigating the quality of numerical verification methods for solutions of ordinary and partial differential equations.

  7. Analysis of multiple scattering effects in optical Doppler tomography

    DEFF Research Database (Denmark)

    Yura, H.T.; Thrane, L.; Andersen, Peter E.

    2005-01-01

    Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where...... multiple scattering effects are included. The purpose of this analysis is to determine how multiple scattering affects the estimation of the depth-resolved localized flow velocity. Depth-resolved velocity estimates are obtained directly from the corresponding mean or standard deviation of the observed...

  8. Error analysis of mathematical problems on TIMSS: A case of Indonesian secondary students

    Science.gov (United States)

    Priyani, H. A.; Ekawati, R.

    2018-01-01

    Indonesian students’ competence in solving mathematical problems is still considered as weak. It was pointed out by the results of international assessment such as TIMSS. This might be caused by various types of errors made. Hence, this study aimed at identifying students’ errors in solving mathematical problems in TIMSS in the topic of numbers that considered as the fundamental concept in Mathematics. This study applied descriptive qualitative analysis. The subject was three students with most errors in the test indicators who were taken from 34 students of 8th graders. Data was obtained through paper and pencil test and student’s’ interview. The error analysis indicated that in solving Applying level problem, the type of error that students made was operational errors. In addition, for reasoning level problem, there are three types of errors made such as conceptual errors, operational errors and principal errors. Meanwhile, analysis of the causes of students’ errors showed that students did not comprehend the mathematical problems given.

  9. System Matrix Analysis for Computed Tomography Imaging

    Science.gov (United States)

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  10. Tomography

    International Nuclear Information System (INIS)

    Barrett, H.H.; Gordon, S.; Swindell, W.

    1980-01-01

    Apparatus is described for generating a two-dimensional back-projected image of a slice of an object in tomography. The apparatus uses optical techniques to perform the functions of filtering and back projection. Central to the technique is a cylindrical drum which rotates at a fast rate and whose rotational axis tilts at a slower rate. The novel method overcomes the problem of image blurring due to motion which occurs in many tomographic techniques. It also has the advantages of being less expensive and simpler compared to tomography using digital processing techniques which require fast computers. (UK)

  11. Reduction in the ionospheric error for a single-frequency GPS timing solution using tomography

    Directory of Open Access Journals (Sweden)

    Cathryn N. Mitchell

    2009-06-01

    Full Text Available

    Abstract

    Single-frequency Global Positioning System (GPS receivers do not accurately compensate for the ionospheric delay imposed upon a GPS signal. They rely upon models to compensate for the ionosphere. This delay compensation can be improved by measuring it directly with a dual-frequency receiver, or by monitoring the ionosphere using real-time maps. This investigation uses a 4D tomographic algorithm, Multi Instrument Data Analysis System (MIDAS, to correct for the ionospheric delay and compares the results to existing single and dualfrequency techniques. Maps of the ionospheric electron density, across Europe, are produced by using data collected from a fixed network of dual-frequency GPS receivers. Single-frequency pseudorange observations are corrected by using the maps to find the excess propagation delay on the GPS L1 signals. Days during the solar maximum year 2002 and the October 2003 storm have been chosen to display results when the ionospheric delays are large and variable. Results that improve upon the use of existing ionospheric models are achieved by applying MIDAS to fixed and mobile single-frequency GPS timing solutions. The approach offers the potential for corrections to be broadcast over a local region, or provided via the internet and allows timing accuracies to within 10 ns to be achieved.



  12. Error Analysis of CM Data Products Sources of Uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eckert-Gallup, Aubrey Celia [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cochran, Lainy Dromgoole [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kraus, Terrence D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Allen, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Beal, Bill [National Security Technologies, Joint Base Andrews, MD (United States); Okada, Colin [National Security Technologies, LLC. (NSTec), Las Vegas, NV (United States); Simpson, Mathew [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-01

    This goal of this project is to address the current inability to assess the overall error and uncertainty of data products developed and distributed by DOE’s Consequence Management (CM) Program. This is a widely recognized shortfall, the resolution of which would provide a great deal of value and defensibility to the analysis results, data products, and the decision making process that follows this work. A global approach to this problem is necessary because multiple sources of error and uncertainty contribute to the ultimate production of CM data products. Therefore, this project will require collaboration with subject matter experts across a wide range of FRMAC skill sets in order to quantify the types of uncertainty that each area of the CM process might contain and to understand how variations in these uncertainty sources contribute to the aggregated uncertainty present in CM data products. The ultimate goal of this project is to quantify the confidence level of CM products to ensure that appropriate public and worker protections decisions are supported by defensible analysis.

  13. Improving patient safety in radiotherapy through error reporting and analysis

    International Nuclear Information System (INIS)

    Findlay, Ú.; Best, H.; Ottrey, M.

    2016-01-01

    Aim: To improve patient safety in radiotherapy (RT) through the analysis and publication of radiotherapy errors and near misses (RTE). Materials and methods: RTE are submitted on a voluntary basis by NHS RT departments throughout the UK to the National Reporting and Learning System (NRLS) or directly to Public Health England (PHE). RTE are analysed by PHE staff using frequency trend analysis based on the classification and pathway coding from Towards Safer Radiotherapy (TSRT). PHE in conjunction with the Patient Safety in Radiotherapy Steering Group publish learning from these events, on a triannual and summarised on a biennial basis, so their occurrence might be mitigated. Results: Since the introduction of this initiative in 2010, over 30,000 (RTE) reports have been submitted. The number of RTE reported in each biennial cycle has grown, ranging from 680 (2010) to 12,691 (2016) RTE. The vast majority of the RTE reported are lower level events, thus not affecting the outcome of patient care. Of the level 1 and 2 incidents reported, it is known the majority of them affected only one fraction of a course of treatment. This means that corrective action could be taken over the remaining treatment fractions so the incident did not have a significant impact on the patient or the outcome of their treatment. Analysis of the RTE reports demonstrates that generation of error is not confined to one professional group or to any particular point in the pathway. It also indicates that the pattern of errors is replicated across service providers in the UK. Conclusion: Use of the terminology, classification and coding of TSRT, together with implementation of the national voluntary reporting system described within this report, allows clinical departments to compare their local analysis to the national picture. Further opportunities to improve learning from this dataset must be exploited through development of the analysis and development of proactive risk management strategies

  14. Feature-based analysis for quality assessment of x-ray computed tomography measurements

    International Nuclear Information System (INIS)

    Nardelli, Vitor C; Arenhart, Francisco A; Donatelli, Gustavo D; Porath, Maurício C; Niggemann, Christian; Schmitt, Robert

    2012-01-01

    This paper presents an approach to assess the quality of the data extracted with computed tomography (CT) measuring systems to perform geometrical evaluations. The approach consists in analyzing the error features introduced by the CT measuring system during the extraction operation. The analysis of the features is performed qualitatively (using graphical analysis tools) and/or quantitatively (by means of the root-mean-square deviation parameter of the error features). The approach was used to analyze four sets of measurements performed with an industrial x-ray cone beam CT measuring system. Three test parts were used in the experiments: a high accuracy manufacturing multi-wave standard, a calibrated step cylinder and a calibrated production part. The results demonstrate the usefulness of the approach to gain knowledge on CT measuring processes and improve the quality of CT geometrical evaluations. Advantages and limitations of the approach are discussed. (paper)

  15. Preliminary frequency-domain analysis for the reconstructed spatial resolution of muon tomography

    Science.gov (United States)

    Yu, B.; Zhao, Z.; Wang, X.; Wang, Y.; Wu, D.; Zeng, Z.; Zeng, M.; Yi, H.; Luo, Z.; Yue, X.; Cheng, J.

    2014-11-01

    Muon tomography is an advanced technology to non-destructively detect high atomic number materials. It exploits the multiple Coulomb scattering information of muon to reconstruct the scattering density image of the traversed object. Because of the statistics of muon scattering, the measurement error of system and the data incompleteness, the reconstruction is always accompanied with a certain level of interference, which will influence the reconstructed spatial resolution. While statistical noises can be reduced by extending the measuring time, system parameters determine the ultimate spatial resolution that one system can reach. In this paper, an effective frequency-domain model is proposed to analyze the reconstructed spatial resolution of muon tomography. The proposed method modifies the resolution analysis in conventional computed tomography (CT) to fit the different imaging mechanism in muon scattering tomography. The measured scattering information is described in frequency domain, then a relationship between the measurements and the original image is proposed in Fourier domain, which is named as "Muon Central Slice Theorem". Furthermore, a preliminary analytical expression of the ultimate reconstructed spatial is derived, and the simulations are performed for validation. While the method is able to predict the ultimate spatial resolution of a given system, it can also be utilized for the optimization of system design and construction.

  16. Preliminary frequency-domain analysis for the reconstructed spatial resolution of muon tomography

    International Nuclear Information System (INIS)

    Yu, B.; Zhao, Z.; Wang, X.; Wang, Y.; Wu, D.; Zeng, Z.; Zeng, M.; Yi, H.; Luo, Z.; Yue, X.; Cheng, J.

    2014-01-01

    Muon tomography is an advanced technology to non-destructively detect high atomic number materials. It exploits the multiple Coulomb scattering information of muon to reconstruct the scattering density image of the traversed object. Because of the statistics of muon scattering, the measurement error of system and the data incompleteness, the reconstruction is always accompanied with a certain level of interference, which will influence the reconstructed spatial resolution. While statistical noises can be reduced by extending the measuring time, system parameters determine the ultimate spatial resolution that one system can reach. In this paper, an effective frequency-domain model is proposed to analyze the reconstructed spatial resolution of muon tomography. The proposed method modifies the resolution analysis in conventional computed tomography (CT) to fit the different imaging mechanism in muon scattering tomography. The measured scattering information is described in frequency domain, then a relationship between the measurements and the original image is proposed in Fourier domain, which is named as M uon Central Slice Theorem . Furthermore, a preliminary analytical expression of the ultimate reconstructed spatial is derived, and the simulations are performed for validation. While the method is able to predict the ultimate spatial resolution of a given system, it can also be utilized for the optimization of system design and construction

  17. Error analysis and prevention of cosmic ion-induced soft errors in static CMOS RAMS

    International Nuclear Information System (INIS)

    Diehl, S.E.; Ochoa, A. Jr.; Dressendorfer, P.V.; Koga, R.; Kolasinski, W.A.

    1982-06-01

    Cosmic ray interactions with memory cells are known to cause temporary, random, bit errors in some designs. The sensitivity of polysilicon gate CMOS static RAM designs to logic upset by impinging ions has been studied using computer simulations and experimental heavy ion bombardment. Results of the simulations are confirmed by experimental upset cross-section data. Analytical models have been extended to determine and evaluate design modifications which reduce memory cell sensitivity to cosmic ions. A simple design modification, the addition of decoupling resistance in the feedback path, is shown to produce static RAMs immune to cosmic ray-induced bit errors

  18. Estimation error algorithm at analysis of beta-spectra

    International Nuclear Information System (INIS)

    Bakovets, N.V.; Zhukovskij, A.I.; Zubarev, V.N.; Khadzhinov, E.M.

    2005-01-01

    This work describes the estimation error algorithm at the operations with beta-spectrums, as well as compares the theoretical and experimental errors by the processing of beta-channel's data. (authors)

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

    Indian Academy of Sciences (India)

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

  20. Tomography

    International Nuclear Information System (INIS)

    Allan, C.J.; Keller, N.A.; Lupton, L.R.; Taylor, T.; Tonner, P.D.

    1984-10-01

    Tomography is a non-intrusive imaging technique being developed at CRNL as an industrial tool for generating quantitative cross-sectional density maps of objects. Of most interest is tomography's ability to: distinguish features within complex geometries where other NDT techniques fail because of the complexity of the geometry; detect/locate small density changes/defects within objects, e.g. void fraction measurements within thick-walled vessels, shrink cavities in castings, etc.; provide quantitative data that can be used in analyses, e.g. of complex processes, or fracture mechanics; and provide objective quantitative data that can be used for (computer-based) quality assurance decisions, thereby reducing and in some cases eliminating the present subjectivity often encountered in NDT. The CRNL program is reviewed and examples are presented to illustrate the potential and the limitations of the technology

  1. Accommodating error analysis in comparison and clustering of molecular fingerprints.

    Science.gov (United States)

    Salamon, H; Segal, M R; Ponce de Leon, A; Small, P M

    1998-01-01

    Molecular epidemiologic studies of infectious diseases rely on pathogen genotype comparisons, which usually yield patterns comprising sets of DNA fragments (DNA fingerprints). We use a highly developed genotyping system, IS6110-based restriction fragment length polymorphism analysis of Mycobacterium tuberculosis, to develop a computational method that automates comparison of large numbers of fingerprints. Because error in fragment length measurements is proportional to fragment length and is positively correlated for fragments within a lane, an align-and-count method that compensates for relative scaling of lanes reliably counts matching fragments between lanes. Results of a two-step method we developed to cluster identical fingerprints agree closely with 5 years of computer-assisted visual matching among 1,335 M. tuberculosis fingerprints. Fully documented and validated methods of automated comparison and clustering will greatly expand the scope of molecular epidemiology.

  2. Error-rate performance analysis of opportunistic regenerative relaying

    KAUST Repository

    Tourki, Kamel

    2011-09-01

    In this paper, we investigate an opportunistic relaying scheme where the selected relay assists the source-destination (direct) communication. In our study, we consider a regenerative opportunistic relaying scheme in which the direct path can be considered unusable, and takes into account the effect of the possible erroneously detected and transmitted data at the best relay. We first derive the exact statistics of each hop, in terms of probability density function (PDF). Then, the PDFs are used to determine accurate closed form expressions for end-to-end bit-error rate (BER) of binary phase-shift keying (BPSK) modulation where the detector may use maximum ration combining (MRC) or selection combining (SC). Finally, we validate our analysis by showing that performance simulation results coincide with our analytical results over linear network (LN) architecture and considering Rayleigh fading channels. © 2011 IEEE.

  3. Kitchen Physics: Lessons in Fluid Pressure and Error Analysis

    Science.gov (United States)

    Vieyra, Rebecca Elizabeth; Vieyra, Chrystian; Macchia, Stefano

    2017-02-01

    Although the advent and popularization of the "flipped classroom" tends to center around at-home video lectures, teachers are increasingly turning to at-home labs for enhanced student engagement. This paper describes two simple at-home experiments that can be accomplished in the kitchen. The first experiment analyzes the density of four liquids using a waterproof case and a smartphone barometer in a container, sink, or tub. The second experiment determines the relationship between pressure and temperature of an ideal gas in a constant volume container placed momentarily in a refrigerator freezer. These experiences provide a ripe opportunity both for learning fundamental physics concepts as well as to investigate a variety of error analysis techniques that are frequently overlooked in introductory physics courses.

  4. Error analysis of acceleration control loops of a synchrotron

    International Nuclear Information System (INIS)

    Zhang, S.Y.; Weng, W.T.

    1991-01-01

    For beam control during acceleration, it is conventional to derive the frequency from an external reference, be it a field marker or an external oscillator, to provide phase and radius feedback loops to ensure the phase stability, radial position and emittance integrity of the beam. The open and closed loop behaviors of both feedback control and their response under the possible frequency, phase and radius errors are derived from fundamental principles and equations. The stability of the loops is investigated under a wide range of variations of the gain and time delays. Actual system performance of the AGS Booster is analyzed and compared to commissioning experiences. Such analysis is useful for setting design criteria and tolerances for new proton synchrotrons. 4 refs., 13 figs

  5. The error performance analysis over cyclic redundancy check codes

    Science.gov (United States)

    Yoon, Hee B.

    1991-06-01

    The burst error is generated in digital communication networks by various unpredictable conditions, which occur at high error rates, for short durations, and can impact services. To completely describe a burst error one has to know the bit pattern. This is impossible in practice on working systems. Therefore, under the memoryless binary symmetric channel (MBSC) assumptions, the performance evaluation or estimation schemes for digital signal 1 (DS1) transmission systems carrying live traffic is an interesting and important problem. This study will present some analytical methods, leading to efficient detecting algorithms of burst error using cyclic redundancy check (CRC) code. The definition of burst error is introduced using three different models. Among the three burst error models, the mathematical model is used in this study. The probability density function, function(b) of burst error of length b is proposed. The performance of CRC-n codes is evaluated and analyzed using function(b) through the use of a computer simulation model within CRC block burst error. The simulation result shows that the mean block burst error tends to approach the pattern of the burst error which random bit errors generate.

  6. SPACE-BORNE LASER ALTIMETER GEOLOCATION ERROR ANALYSIS

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2018-05-01

    Full Text Available This paper reviews the development of space-borne laser altimetry technology over the past 40 years. Taking the ICESAT satellite as an example, a rigorous space-borne laser altimeter geolocation model is studied, and an error propagation equation is derived. The influence of the main error sources, such as the platform positioning error, attitude measurement error, pointing angle measurement error and range measurement error, on the geolocation accuracy of the laser spot are analysed by simulated experiments. The reasons for the different influences on geolocation accuracy in different directions are discussed, and to satisfy the accuracy of the laser control point, a design index for each error source is put forward.

  7. Medication errors as malpractice-a qualitative content analysis of 585 medication errors by nurses in Sweden.

    Science.gov (United States)

    Björkstén, Karin Sparring; Bergqvist, Monica; Andersén-Karlsson, Eva; Benson, Lina; Ulfvarson, Johanna

    2016-08-24

    Many studies address the prevalence of medication errors but few address medication errors serious enough to be regarded as malpractice. Other studies have analyzed the individual and system contributory factor leading to a medication error. Nurses have a key role in medication administration, and there are contradictory reports on the nurses' work experience in relation to the risk and type for medication errors. All medication errors where a nurse was held responsible for malpractice (n = 585) during 11 years in Sweden were included. A qualitative content analysis and classification according to the type and the individual and system contributory factors was made. In order to test for possible differences between nurses' work experience and associations within and between the errors and contributory factors, Fisher's exact test was used, and Cohen's kappa (k) was performed to estimate the magnitude and direction of the associations. There were a total of 613 medication errors in the 585 cases, the most common being "Wrong dose" (41 %), "Wrong patient" (13 %) and "Omission of drug" (12 %). In 95 % of the cases, an average of 1.4 individual contributory factors was found; the most common being "Negligence, forgetfulness or lack of attentiveness" (68 %), "Proper protocol not followed" (25 %), "Lack of knowledge" (13 %) and "Practice beyond scope" (12 %). In 78 % of the cases, an average of 1.7 system contributory factors was found; the most common being "Role overload" (36 %), "Unclear communication or orders" (30 %) and "Lack of adequate access to guidelines or unclear organisational routines" (30 %). The errors "Wrong patient due to mix-up of patients" and "Wrong route" and the contributory factors "Lack of knowledge" and "Negligence, forgetfulness or lack of attentiveness" were more common in less experienced nurses. The experienced nurses were more prone to "Practice beyond scope of practice" and to make errors in spite of "Lack of adequate

  8. Analysis of error functions in speckle shearing interferometry

    International Nuclear Information System (INIS)

    Wan Saffiey Wan Abdullah

    2001-01-01

    Electronic Speckle Pattern Shearing Interferometry (ESPSI) or shearography has successfully been used in NDT for slope (∂w/ (∂x and / or (∂w/ (∂y) measurement while strain measurement (∂u/ ∂x, ∂v/ ∂y, ∂u/ ∂y and (∂v/ (∂x) is still under investigation. This method is well accepted in industrial applications especially in the aerospace industry. Demand of this method is increasing due to complexity of the test materials and objects. ESPSI has successfully performed in NDT only for qualitative measurement whilst quantitative measurement is the current aim of many manufacturers. Industrial use of such equipment is being completed without considering the errors arising from numerous sources, including wavefront divergence. The majority of commercial systems are operated with diverging object illumination wave fronts without considering the curvature of the object illumination wavefront or the object geometry, when calculating the interferometer fringe function and quantifying data. This thesis reports the novel approach in quantified maximum phase change difference analysis for derivative out-of-plane (OOP) and in-plane (IP) cases that propagate from the divergent illumination wavefront compared to collimated illumination. The theoretical of maximum phase difference is formulated by means of three dependent variables, these being the object distance, illuminated diameter, center of illuminated area and camera distance and illumination angle. The relative maximum phase change difference that may contributed to the error in the measurement analysis in this scope of research is defined by the difference of maximum phase difference value measured by divergent illumination wavefront relative to the maximum phase difference value of collimated illumination wavefront, taken at the edge of illuminated area. Experimental validation using test objects for derivative out-of-plane and derivative in-plane deformation, using a single illumination wavefront

  9. Analysis of error-correction constraints in an optical disk

    Science.gov (United States)

    Roberts, Jonathan D.; Ryley, Alan; Jones, David M.; Burke, David

    1996-07-01

    The compact disk read-only memory (CD-ROM) is a mature storage medium with complex error control. It comprises four levels of Reed Solomon codes allied to a sequence of sophisticated interleaving strategies and 8:14 modulation coding. New storage media are being developed and introduced that place still further demands on signal processing for error correction. It is therefore appropriate to explore thoroughly the limit of existing strategies to assess future requirements. We describe a simulation of all stages of the CD-ROM coding, modulation, and decoding. The results of decoding the burst error of a prescribed number of modulation bits are discussed in detail. Measures of residual uncorrected error within a sector are displayed by C1, C2, P, and Q error counts and by the status of the final cyclic redundancy check (CRC). Where each data sector is encoded separately, it is shown that error-correction performance against burst errors depends critically on the position of the burst within a sector. The C1 error measures the burst length, whereas C2 errors reflect the burst position. The performance of Reed Solomon product codes is shown by the P and Q statistics. It is shown that synchronization loss is critical near the limits of error correction. An example is given of miscorrection that is identified by the CRC check.

  10. Analysis of the "naming game" with learning errors in communications.

    Science.gov (United States)

    Lou, Yang; Chen, Guanrong

    2015-07-16

    Naming game simulates the process of naming an objective by a population of agents organized in a certain communication network. By pair-wise iterative interactions, the population reaches consensus asymptotically. We study naming game with communication errors during pair-wise conversations, with error rates in a uniform probability distribution. First, a model of naming game with learning errors in communications (NGLE) is proposed. Then, a strategy for agents to prevent learning errors is suggested. To that end, three typical topologies of communication networks, namely random-graph, small-world and scale-free networks, are employed to investigate the effects of various learning errors. Simulation results on these models show that 1) learning errors slightly affect the convergence speed but distinctively increase the requirement for memory of each agent during lexicon propagation; 2) the maximum number of different words held by the population increases linearly as the error rate increases; 3) without applying any strategy to eliminate learning errors, there is a threshold of the learning errors which impairs the convergence. The new findings may help to better understand the role of learning errors in naming game as well as in human language development from a network science perspective.

  11. AGAPE-ET for human error analysis of emergency tasks and its application

    International Nuclear Information System (INIS)

    Kim, J. H.; Jeong, W. D.

    2002-01-01

    The paper presents a proceduralised human reliability analysis (HRA) methodology, AGAPE-ET (A Guidance And Procedure for Human Error Analysis for Emergency Tasks), covering both qualitative error analysis and quantification of human error probability (HEP) of emergency tasks in nuclear power plants. The AGAPE-ET method is based on the simplified cognitive model. By each cognitive function, error causes or error-likely situations have been identified considering the characteristics of the performance of each cognitive function and influencing mechanism of the performance influencing factors (PIFs) on the cognitive function. Then, error analysis items have been determined from the identified error causes or error-likely situations and a human error analysis procedure based on the error analysis items is organised to help the analysts cue or guide overall human error analysis. The basic scheme for the quantification of HEP consists in the multiplication of the BHEP assigned by the error analysis item and the weight from the influencing factors decision tree (IFDT) constituted by cognitive function. The method can be characterised by the structured identification of the weak points of the task required to perform and the efficient analysis process that the analysts have only to carry out with the necessary cognitive functions. The paper also presents the application of AGAPE-ET to 31 nuclear emergency tasks and its results

  12. An error taxonomy system for analysis of haemodialysis incidents.

    Science.gov (United States)

    Gu, Xiuzhu; Itoh, Kenji; Suzuki, Satoshi

    2014-12-01

    This paper describes the development of a haemodialysis error taxonomy system for analysing incidents and predicting the safety status of a dialysis organisation. The error taxonomy system was developed by adapting an error taxonomy system which assumed no specific specialty to haemodialysis situations. Its application was conducted with 1,909 incident reports collected from two dialysis facilities in Japan. Over 70% of haemodialysis incidents were reported as problems or complications related to dialyser, circuit, medication and setting of dialysis condition. Approximately 70% of errors took place immediately before and after the four hours of haemodialysis therapy. Error types most frequently made in the dialysis unit were omission and qualitative errors. Failures or complications classified to staff human factors, communication, task and organisational factors were found in most dialysis incidents. Device/equipment/materials, medicine and clinical documents were most likely to be involved in errors. Haemodialysis nurses were involved in more incidents related to medicine and documents, whereas dialysis technologists made more errors with device/equipment/materials. This error taxonomy system is able to investigate incidents and adverse events occurring in the dialysis setting but is also able to estimate safety-related status of an organisation, such as reporting culture. © 2014 European Dialysis and Transplant Nurses Association/European Renal Care Association.

  13. Generalization error analysis: deep convolutional neural network in mammography

    Science.gov (United States)

    Richter, Caleb D.; Samala, Ravi K.; Chan, Heang-Ping; Hadjiiski, Lubomir; Cha, Kenny

    2018-02-01

    We conducted a study to gain understanding of the generalizability of deep convolutional neural networks (DCNNs) given their inherent capability to memorize data. We examined empirically a specific DCNN trained for classification of masses on mammograms. Using a data set of 2,454 lesions from 2,242 mammographic views, a DCNN was trained to classify masses into malignant and benign classes using transfer learning from ImageNet LSVRC-2010. We performed experiments with varying amounts of label corruption and types of pixel randomization to analyze the generalization error for the DCNN. Performance was evaluated using the area under the receiver operating characteristic curve (AUC) with an N-fold cross validation. Comparisons were made between the convergence times, the inference AUCs for both the training set and the test set of the original image patches without corruption, and the root-mean-squared difference (RMSD) in the layer weights of the DCNN trained with different amounts and methods of corruption. Our experiments observed trends which revealed that the DCNN overfitted by memorizing corrupted data. More importantly, this study improved our understanding of DCNN weight updates when learning new patterns or new labels. Although we used a specific classification task with the ImageNet as example, similar methods may be useful for analysis of the DCNN learning processes, especially those that employ transfer learning for medical image analysis where sample size is limited and overfitting risk is high.

  14. EEL spectroscopic tomography: Towards a new dimension in nanomaterials analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yedra, Lluis, E-mail: llyedra@el.ub.es [Laboratory of Electron Nanoscopies (LENS)-MIND/IN2UB, Dept. d' Electronica, Universitat de Barcelona, c/ Marti Franques 1, E-08028 Barcelona (Spain); CCiT, Scientific and Technological Centers, Universitat de Barcelona, C/Lluis Sole i Sabaris 1, E-08028 Barcelona (Spain); Eljarrat, Alberto [Laboratory of Electron Nanoscopies (LENS)-MIND/IN2UB, Dept. d' Electronica, Universitat de Barcelona, c/ Marti Franques 1, E-08028 Barcelona (Spain); Arenal, Raul [Laboratorio de Microscopias Avanzadas (LMA), Instituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Fundacion ARAID, E-50004 Zaragoza (Spain); Pellicer, Eva; Cabo, Moises [Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Lopez-Ortega, Alberto; Estrader, Marta [CIN2(CIN-CSIC) and Universitat Autonoma de Barcelona, Catalan Institute of Nanotechnology, Campus de la UAB, E-08193 Bellaterra (Spain); Sort, Jordi [Institucio Catalana de Recerca i Estudis Avancats (ICREA), Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Baro, Maria Dolors [Departament de Fisica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); and others

    2012-11-15

    Electron tomography is a widely spread technique for recovering the three dimensional (3D) shape of nanostructured materials. Using a spectroscopic signal to achieve a reconstruction adds a fourth chemical dimension to the 3D structure. Up to date, energy filtering of the images in the transmission electron microscope (EFTEM) is the usual spectroscopic method even if most of the information in the spectrum is lost. Unlike EFTEM tomography, the use of electron energy-loss spectroscopy (EELS) spectrum images (SI) for tomographic reconstruction retains all chemical information, and the possibilities of this new approach still remain to be fully exploited. In this article we prove the feasibility of EEL spectroscopic tomography at low voltages (80 kV) and short acquisition times from data acquired using an aberration corrected instrument and data treatment by Multivariate Analysis (MVA), applied to Fe{sub x}Co{sub (3-x)}O{sub 4}@Co{sub 3}O{sub 4} mesoporous materials. This approach provides a new scope into materials; the recovery of full EELS signal in 3D. -- Highlights: Black-Right-Pointing-Pointer EELS-SI tomography was performed at low voltage and low acquisition times. Black-Right-Pointing-Pointer MVA has been applied for noise reduction and information extraction. Black-Right-Pointing-Pointer Tomographic reconstruction has been achieved for chemical information. Black-Right-Pointing-Pointer Elemental distribution extraction in 3D has been proved.

  15. Analysis of Students' Errors on Linear Programming at Secondary ...

    African Journals Online (AJOL)

    The purpose of this study was to identify secondary school students' errors on linear programming at 'O' level. It is based on the fact that students' errors inform teaching hence an essential tool for any serious mathematics teacher who intends to improve mathematics teaching. The study was guided by a descriptive survey ...

  16. THE PRACTICAL ANALYSIS OF FINITE ELEMENTS METHOD ERRORS

    Directory of Open Access Journals (Sweden)

    Natalia Bakhova

    2011-03-01

    Full Text Available Abstract. The most important in the practical plan questions of reliable estimations of finite elementsmethod errors are considered. Definition rules of necessary calculations accuracy are developed. Methodsand ways of the calculations allowing receiving at economical expenditures of computing work the best finalresults are offered.Keywords: error, given the accuracy, finite element method, lagrangian and hermitian elements.

  17. Interfractional and intrafractional errors assessed by daily cone-beam computed tomography in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy. A prospective study

    International Nuclear Information System (INIS)

    Lu Heming; Lin Hui; Feng Guosheng

    2012-01-01

    This prospective study was to assess interfractional and intrafractional errors and to estimate appropriate margins for planning target volume (PTV) by using daily cone-beam computed tomography (CBCT) guidance in nasopharyngeal carcinoma (NPC). Daily pretreatment and post-treatment CBCT scans were acquired separately after initial patient setup and after the completion of each treatment fraction in 10 patients treated with intensity-modulated radiation therapy (IMRT). Online corrections were made before treatment if any translational setup error was found. Interfractional and intrafractional errors were recorded in the right-left (RL), superior-inferior (SI) and anterior-posterior (AP) directions. For the translational shifts, interfractional errors >2 mm occurred in 21.7% of measurements in the RL direction, 12.7% in the SI direction and 34.1% in the AP direction, respectively. Online correction resulted in 100% of residual errors ≤2 mm in the RL and SI directions, and 95.5% of residual errors ≤2 mm in the AP direction. No residual errors >3 mm occurred in the three directions. For the rotational shifts, a significant reduction was found in the magnitudes of residual errors compared with those of interfractional errors. A margin of 4.9 mm, 4.0 mm and 6.3 mm was required in the RL, SI and AP directions, respectively, when daily CBCT scans were not performed. With daily CBCT, the margins were reduced to 1.2 mm in all directions. In conclusion, daily CBCT guidance is an effective modality to improve the accuracy of IMRT for NPC. The online correction could result in a 70-81% reduction in margin size. (author)

  18. Wavelet analysis in two-dimensional tomography

    Science.gov (United States)

    Burkovets, Dimitry N.

    2002-02-01

    The diagnostic possibilities of wavelet-analysis of coherent images of connective tissue in its pathological changes diagnostics. The effectiveness of polarization selection in obtaining wavelet-coefficients' images is also shown. The wavelet structures, characterizing the process of skin psoriasis, bone-tissue osteoporosis have been analyzed. The histological sections of physiological normal and pathologically changed samples of connective tissue of human skin and spongy bone tissue have been analyzed.

  19. Evaluation and Error Analysis for a Solar Thermal Receiver

    International Nuclear Information System (INIS)

    Pfander, M.

    2001-01-01

    In the following study a complete balance over the REFOS receiver module, mounted on the tower power plant CESA-1 at the Plataforma Solar de Almeria (PSA), is carried out. Additionally an error inspection of the various measurement techniques used in the REFOS project is made. Especially the flux measurement system Pro hermes that is used to determine the total entry power of the receiver module and known as a major error source is analysed in detail. Simulations and experiments on the particular instruments are used to determine and quantify possible error sources. After discovering the origin of the errors they are reduced and included in the error calculation. The ultimate result is presented as an overall efficiency of the receiver module in dependence on the flux density at the receiver modules entry plane and the receiver operating temperature. (Author) 26 refs

  20. Evaluation and Error Analysis for a Solar thermal Receiver

    Energy Technology Data Exchange (ETDEWEB)

    Pfander, M.

    2001-07-01

    In the following study a complete balance over the REFOS receiver module, mounted on the tower power plant CESA-1 at the Plataforma Solar de Almeria (PSA), is carried out. Additionally an error inspection of the various measurement techniques used in the REFOS project is made. Especially the flux measurement system Prohermes that is used to determine the total entry power of the receiver module and known as a major error source is analysed in detail. Simulations and experiments on the particular instruments are used to determine and quantify possible error sources. After discovering the origin of the errors they are reduced and included in the error calculation. the ultimate result is presented as an overall efficiency of the receiver module in dependence on the flux density at the receiver module's entry plane and the receiver operating temperature. (Author) 26 refs.

  1. Forest Analysis by Single-Pass Millimeterwave SAR Tomography

    OpenAIRE

    Schmitt, Michael; Zhu, Xiao Xiang

    2016-01-01

    Recent investigations show that millimeterwave SAR tomography provides an interesting means for the analysis of forested areas, especially if single-pass systems are employed. Providing very high resolutions in the decimeter domain and highly coherent data also for slightly windy conditions, even individual trees can be considered. Besides, it has been shown that a certain amount of canopy penetration is possible in spite of the short wavelength.

  2. Spectrogram Image Analysis of Error Signals for Minimizing Impulse Noise

    Directory of Open Access Journals (Sweden)

    Jeakwan Kim

    2016-01-01

    Full Text Available This paper presents the theoretical and experimental study on the spectrogram image analysis of error signals for minimizing the impulse input noises in the active suppression of noise. Impulse inputs of some specific wave patterns as primary noises to a one-dimensional duct with the length of 1800 mm are shown. The convergence speed of the adaptive feedforward algorithm based on the least mean square approach was controlled by a normalized step size which was incorporated into the algorithm. The variations of the step size govern the stability as well as the convergence speed. Because of this reason, a normalized step size is introduced as a new method for the control of impulse noise. The spectrogram images which indicate the degree of the attenuation of the impulse input noises are considered to represent the attenuation with the new method. The algorithm is extensively investigated in both simulation and real-time control experiment. It is demonstrated that the suggested algorithm worked with a nice stability and performance against impulse noises. The results in this study can be used for practical active noise control systems.

  3. Latent human error analysis and efficient improvement strategies by fuzzy TOPSIS in aviation maintenance tasks.

    Science.gov (United States)

    Chiu, Ming-Chuan; Hsieh, Min-Chih

    2016-05-01

    The purposes of this study were to develop a latent human error analysis process, to explore the factors of latent human error in aviation maintenance tasks, and to provide an efficient improvement strategy for addressing those errors. First, we used HFACS and RCA to define the error factors related to aviation maintenance tasks. Fuzzy TOPSIS with four criteria was applied to evaluate the error factors. Results show that 1) adverse physiological states, 2) physical/mental limitations, and 3) coordination, communication, and planning are the factors related to airline maintenance tasks that could be addressed easily and efficiently. This research establishes a new analytic process for investigating latent human error and provides a strategy for analyzing human error using fuzzy TOPSIS. Our analysis process complements shortages in existing methodologies by incorporating improvement efficiency, and it enhances the depth and broadness of human error analysis methodology. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  4. ERM model analysis for adaptation to hydrological model errors

    Science.gov (United States)

    Baymani-Nezhad, M.; Han, D.

    2018-05-01

    Hydrological conditions are changed continuously and these phenomenons generate errors on flood forecasting models and will lead to get unrealistic results. Therefore, to overcome these difficulties, a concept called model updating is proposed in hydrological studies. Real-time model updating is one of the challenging processes in hydrological sciences and has not been entirely solved due to lack of knowledge about the future state of the catchment under study. Basically, in terms of flood forecasting process, errors propagated from the rainfall-runoff model are enumerated as the main source of uncertainty in the forecasting model. Hence, to dominate the exciting errors, several methods have been proposed by researchers to update the rainfall-runoff models such as parameter updating, model state updating, and correction on input data. The current study focuses on investigations about the ability of rainfall-runoff model parameters to cope with three types of existing errors, timing, shape and volume as the common errors in hydrological modelling. The new lumped model, the ERM model, has been selected for this study to evaluate its parameters for its use in model updating to cope with the stated errors. Investigation about ten events proves that the ERM model parameters can be updated to cope with the errors without the need to recalibrate the model.

  5. Human Error Assessmentin Minefield Cleaning Operation Using Human Event Analysis

    Directory of Open Access Journals (Sweden)

    Mohammad Hajiakbari

    2015-12-01

    Full Text Available Background & objective: Human error is one of the main causes of accidents. Due to the unreliability of the human element and the high-risk nature of demining operations, this study aimed to assess and manage human errors likely to occur in such operations. Methods: This study was performed at a demining site in war zones located in the West of Iran. After acquiring an initial familiarity with the operations, methods, and tools of clearing minefields, job task related to clearing landmines were specified. Next, these tasks were studied using HTA and related possible errors were assessed using ATHEANA. Results: de-mining task was composed of four main operations, including primary detection, technical identification, investigation, and neutralization. There were found four main reasons for accidents occurring in such operations; walking on the mines, leaving mines with no action, error in neutralizing operation and environmental explosion. The possibility of human error in mine clearance operations was calculated as 0.010. Conclusion: The main causes of human error in de-mining operations can be attributed to various factors such as poor weather and operating conditions like outdoor work, inappropriate personal protective equipment, personality characteristics, insufficient accuracy in the work, and insufficient time available. To reduce the probability of human error in de-mining operations, the aforementioned factors should be managed properly.

  6. Effective training based on the cause analysis of operation errors

    International Nuclear Information System (INIS)

    Fujita, Eimitsu; Noji, Kunio; Kobayashi, Akira.

    1991-01-01

    The authors have investigated typical error types through our training experience, and analyzed the causes of them. Error types which are observed in simulator training are: (1) lack of knowledge or lack of its applying ability to actual operation; (2) defective mastery of skillbase operation; (3) rote operation or stereotyped manner; (4) mind-setting or lack of redundant verification; (5) lack of team work; (6) misjudgement for the plant overall conditions by operation chief, who directs a reactor operator and a turbine operator in the training. The paper describes training methods used in Japan for BWR utilities to overcome these error types

  7. HUMAN RELIABILITY ANALYSIS DENGAN PENDEKATAN COGNITIVE RELIABILITY AND ERROR ANALYSIS METHOD (CREAM

    Directory of Open Access Journals (Sweden)

    Zahirah Alifia Maulida

    2015-01-01

    Full Text Available Kecelakaan kerja pada bidang grinding dan welding menempati urutan tertinggi selama lima tahun terakhir di PT. X. Kecelakaan ini disebabkan oleh human error. Human error terjadi karena pengaruh lingkungan kerja fisik dan non fisik.Penelitian kali menggunakan skenario untuk memprediksi serta mengurangi kemungkinan terjadinya error pada manusia dengan pendekatan CREAM (Cognitive Reliability and Error Analysis Method. CREAM adalah salah satu metode human reliability analysis yang berfungsi untuk mendapatkan nilai Cognitive Failure Probability (CFP yang dapat dilakukan dengan dua cara yaitu basic method dan extended method. Pada basic method hanya akan didapatkan nilai failure probabailty secara umum, sedangkan untuk extended method akan didapatkan CFP untuk setiap task. Hasil penelitian menunjukkan faktor- faktor yang mempengaruhi timbulnya error pada pekerjaan grinding dan welding adalah kecukupan organisasi, kecukupan dari Man Machine Interface (MMI & dukungan operasional, ketersediaan prosedur/ perencanaan, serta kecukupan pelatihan dan pengalaman. Aspek kognitif pada pekerjaan grinding yang memiliki nilai error paling tinggi adalah planning dengan nilai CFP 0.3 dan pada pekerjaan welding yaitu aspek kognitif execution dengan nilai CFP 0.18. Sebagai upaya untuk mengurangi nilai error kognitif pada pekerjaan grinding dan welding rekomendasi yang diberikan adalah memberikan training secara rutin, work instrucstion yang lebih rinci dan memberikan sosialisasi alat. Kata kunci: CREAM (cognitive reliability and error analysis method, HRA (human reliability analysis, cognitive error Abstract The accidents in grinding and welding sectors were the highest cases over the last five years in PT. X and it caused by human error. Human error occurs due to the influence of working environment both physically and non-physically. This study will implement an approaching scenario called CREAM (Cognitive Reliability and Error Analysis Method. CREAM is one of human

  8. US-LHC IR magnet error analysis and compensation

    International Nuclear Information System (INIS)

    Wei, J.; Ptitsin, V.; Pilat, F.; Tepikian, S.; Gelfand, N.; Wan, W.; Holt, J.

    1998-01-01

    This paper studies the impact of the insertion-region (IR) magnet field errors on LHC collision performance. Compensation schemes including magnet orientation optimization, body-end compensation, tuning shims, and local nonlinear correction are shown to be highly effective

  9. Analysis of error in Monte Carlo transport calculations

    International Nuclear Information System (INIS)

    Booth, T.E.

    1979-01-01

    The Monte Carlo method for neutron transport calculations suffers, in part, because of the inherent statistical errors associated with the method. Without an estimate of these errors in advance of the calculation, it is difficult to decide what estimator and biasing scheme to use. Recently, integral equations have been derived that, when solved, predicted errors in Monte Carlo calculations in nonmultiplying media. The present work allows error prediction in nonanalog Monte Carlo calculations of multiplying systems, even when supercritical. Nonanalog techniques such as biased kernels, particle splitting, and Russian Roulette are incorporated. Equations derived here allow prediction of how much a specific variance reduction technique reduces the number of histories required, to be weighed against the change in time required for calculation of each history. 1 figure, 1 table

  10. Error Analysis for Fourier Methods for Option Pricing

    KAUST Repository

    Hä ppö lä , Juho

    2016-01-01

    We provide a bound for the error committed when using a Fourier method to price European options when the underlying follows an exponential Levy dynamic. The price of the option is described by a partial integro-differential equation (PIDE

  11. Error Analysis of Inertial Navigation Systems Using Test Algorithms

    OpenAIRE

    Vaispacher, Tomáš; Bréda, Róbert; Adamčík, František

    2015-01-01

    Content of this contribution is an issue of inertial sensors errors, specification of inertial measurement units and generating of test signals for Inertial Navigation System (INS). Given the different levels of navigation tasks, part of this contribution is comparison of the actual types of Inertial Measurement Units. Considering this comparison, there is proposed the way of solving inertial sensors errors and their modelling for low – cost inertial navigation applications. The last part is ...

  12. Multivariate statistical analysis of atom probe tomography data

    International Nuclear Information System (INIS)

    Parish, Chad M.; Miller, Michael K.

    2010-01-01

    The application of spectrum imaging multivariate statistical analysis methods, specifically principal component analysis (PCA), to atom probe tomography (APT) data has been investigated. The mathematical method of analysis is described and the results for two example datasets are analyzed and presented. The first dataset is from the analysis of a PM 2000 Fe-Cr-Al-Ti steel containing two different ultrafine precipitate populations. PCA properly describes the matrix and precipitate phases in a simple and intuitive manner. A second APT example is from the analysis of an irradiated reactor pressure vessel steel. Fine, nm-scale Cu-enriched precipitates having a core-shell structure were identified and qualitatively described by PCA. Advantages, disadvantages, and future prospects for implementing these data analysis methodologies for APT datasets, particularly with regard to quantitative analysis, are also discussed.

  13. Analysis of gross error rates in operation of commercial nuclear power stations

    International Nuclear Information System (INIS)

    Joos, D.W.; Sabri, Z.A.; Husseiny, A.A.

    1979-01-01

    Experience in operation of US commercial nuclear power plants is reviewed over a 25-month period. The reports accumulated in that period on events of human error and component failure are examined to evaluate gross operator error rates. The impact of such errors on plant operation and safety is examined through the use of proper taxonomies of error, tasks and failures. Four categories of human errors are considered; namely, operator, maintenance, installation and administrative. The computed error rates are used to examine appropriate operator models for evaluation of operator reliability. Human error rates are found to be significant to a varying degree in both BWR and PWR. This emphasizes the import of considering human factors in safety and reliability analysis of nuclear systems. The results also indicate that human errors, and especially operator errors, do indeed follow the exponential reliability model. (Auth.)

  14. Prevalence and Distribution of Segmentation Errors in Macular Ganglion Cell Analysis of Healthy Eyes Using Cirrus HD-OCT.

    Directory of Open Access Journals (Sweden)

    Rayan A Alshareef

    Full Text Available To determine the frequency of different types of spectral domain optical coherence tomography (SD-OCT scan artifacts and errors in ganglion cell algorithm (GCA in healthy eyes.Infrared image, color-coded map and each of the 128 horizontal b-scans acquired in the macular ganglion cell-inner plexiform layer scans using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA macular cube 512 × 128 protocol in 30 healthy normal eyes were evaluated. The frequency and pattern of each artifact was determined. Deviation of the segmentation line was classified into mild (less than 10 microns, moderate (10-50 microns and severe (more than 50 microns. Each deviation, if present, was noted as upward or downward deviation. Each artifact was further described as per location on the scan and zones in the total scan area.A total of 1029 (26.8% out of total 3840 scans had scan errors. The most common scan error was segmentation error (100%, followed by degraded images (6.70%, blink artifacts (0.09% and out of register artifacts (3.3%. Misidentification of the inner retinal layers was most frequent (62%. Upward Deviation of the segmentation line (47.91% and severe deviation (40.3% were more often noted. Artifacts were mostly located in the central scan area (16.8%. The average number of scans with artifacts per eye was 34.3% and was not related to signal strength on Spearman correlation (p = 0.36.This study reveals that image artifacts and scan errors in SD-OCT GCA analysis are common and frequently involve segmentation errors. These errors may affect inner retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using this feature of SD-OCT device.

  15. Error Analysis of Variations on Larsen's Benchmark Problem

    International Nuclear Information System (INIS)

    Azmy, YY

    2001-01-01

    Error norms for three variants of Larsen's benchmark problem are evaluated using three numerical methods for solving the discrete ordinates approximation of the neutron transport equation in multidimensional Cartesian geometry. The three variants of Larsen's test problem are concerned with the incoming flux boundary conditions: unit incoming flux on the left and bottom edges (Larsen's configuration); unit, incoming flux only on the left edge; unit incoming flux only on the bottom edge. The three methods considered are the Diamond Difference (DD) method, and the constant-approximation versions of the Arbitrarily High Order Transport method of the Nodal type (AHOT-N), and of the Characteristic (AHOT-C) type. The cell-wise error is computed as the difference between the cell-averaged flux computed by each method and the exact value, then the L 1 , L 2 , and L ∞ error norms are calculated. The results of this study demonstrate that while integral error norms, i.e. L 1 , L 2 , converge to zero with mesh refinement, the pointwise L ∞ norm does not due to solution discontinuity across the singular characteristic. Little difference is observed between the error norm behavior of the three methods considered in spite of the fact that AHOT-C is locally exact, suggesting that numerical diffusion across the singular characteristic as the major source of error on the global scale. However, AHOT-C possesses a given accuracy in a larger fraction of computational cells than DD

  16. WORKING MEMORY STRUCTURE REVEALED IN ANALYSIS OF RECALL ERRORS

    Directory of Open Access Journals (Sweden)

    Regina V Ershova

    2017-12-01

    Full Text Available We analyzed working memory errors stemming from 193 Russian college students taking the Tarnow Unchunkable Test utilizing double digit items on a visual display.In three-item trials with at most one error per trial, single incorrect tens and ones digits (“singlets” were overrepresented and made up the majority of errors, indicating a base 10 organization.These errors indicate that there are separate memory maps for each position and that there are pointers that can move primarily within these maps. Several pointers make up a pointer collection. The number of pointer collections possible is the working memory capacity limit. A model for self-organizing maps is constructed in which the organization is created by turning common pointer collections into maps thereby replacing a pointer collection with a single pointer.The factors 5 and 11 were underrepresented in the errors, presumably because base 10 properties beyond positional order were used for error correction, perhaps reflecting the existence of additional maps of integers divisible by 5 and integers divisible by 11.

  17. Human reliability analysis during PSA at Trillo NPP: main characteristics and analysis of diagnostic errors

    International Nuclear Information System (INIS)

    Barquin, M.A.; Gomez, F.

    1998-01-01

    The design difference between Trillo NPP and other Spanish nuclear power plants (basic Westinghouse and General Electric designs) were made clear in the Human Reliability Analysis of the Probabilistic Safety Analysis (PSA) for Trillo NPP. The object of this paper is to describe the most significant characteristics of the Human Reliability Analysis carried out in the PSA, with special emphasis on the possible diagnostic errors and their consequences, based on the characteristics in the Emergency Operations Manual for Trillo NPP. - In the case of human errors before the initiating event (type 1), the existence of four redundancies in most of the plant safety systems, means that the impact of this type or error on the final results of the PSA is insignificant. However, in the case common cause errors, especially in certain calibration errors, some actions are significant in the final equation for core damage - The number of human actions that the operator has to carry out during the accidents (type 3) modelled, is relatively small in comparison with this value in other PSAs. This is basically due to the high level of automation at Rillo NPP - The Plant Operations Manual cannot be strictly considered to be a symptoms-based procedure. The operation Group must select the chapter from the Operations Manual to be followed, after having diagnosed the perturbing event, using for this purpose and Emergency and Anomaly Decision Tree (M.O.3.0.1) based on the different indications, alarms and symptoms present in the plant after the perturbing event. For this reason, it was decided to analyse the possible diagnosis errors. In the bibliography on diagnosis and commission errors available at the present time, there is no precise methodology for the analysis of this type of error and its incorporation into PSAs. The method used in the PSA for Trillo y NPP to evaluate this type of interaction, is to develop a Diagnosis Error Table, the object of which is to identify the situations in

  18. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Taynna Vernalha Rocha [Faculdades Pequeno Principe (FPP), Curitiba, PR (Brazil); Cordova Junior, Arno Lotar; Almeida, Cristiane Maria; Piedade, Pedro Argolo; Silva, Cintia Mara da, E-mail: taynnavra@gmail.com [Centro de Radioterapia Sao Sebastiao, Florianopolis, SC (Brazil); Brincas, Gabriela R. Baseggio [Centro de Diagnostico Medico Imagem, Florianopolis, SC (Brazil); Marins, Priscila; Soboll, Danyel Scheidegger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2016-03-15

    Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5- mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. (author)

  19. Error Analysis of Brailled Instructional Materials Produced by Public School Personnel in Texas

    Science.gov (United States)

    Herzberg, Tina

    2010-01-01

    In this study, a detailed error analysis was performed to determine if patterns of errors existed in braille transcriptions. The most frequently occurring errors were the insertion of letters or words that were not contained in the original print material; the incorrect usage of the emphasis indicator; and the incorrect formatting of titles,…

  20. Error analysis for 1-1/2-loop semiscale system isothermal test data

    International Nuclear Information System (INIS)

    Feldman, E.M.; Naff, S.A.

    1975-05-01

    An error analysis was performed on the measurements made during the isothermal portion of the Semiscale Blowdown and Emergency Core Cooling (ECC) Project. A brief description of the measurement techniques employed, identification of potential sources of errors, and quantification of the errors associated with data is presented. (U.S.)

  1. Morphological analysis of the vestibular aqueduct by computerized tomography images

    International Nuclear Information System (INIS)

    Marques, Sergio Ricardo; Smith, Ricardo Luiz; Isotani, Sadao; Alonso, Luis Garcia; Anadao, Carlos Augusto; Prates, Jose Carlos; Lederman, Henrique Manoel

    2007-01-01

    Objective: In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI). Material and method: Computerized tomography images of vestibular aqueducts were acquired from patients (n = 110) with an age range of 1-92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus. Results: The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm 2 of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm 2 , 2.09 mm, 4.44 mm, and 11.35 mm, respectively. Conclusions: Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant

  2. SU-F-I-03: Correction of Intra-Fractional Set-Up Errors and Target Coverage Based On Cone-Beam Computed Tomography for Cervical Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, JY [Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China); Hong, DL [The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong (China)

    2016-06-15

    Purpose: The purpose of this study is to investigate the patient set-up error and interfraction target coverage in cervical cancer using image-guided adaptive radiotherapy (IGART) with cone-beam computed tomography (CBCT). Methods: Twenty cervical cancer patients undergoing intensity modulated radiotherapy (IMRT) were randomly selected. All patients were matched to the isocenter using laser with the skin markers. Three dimensional CBCT projections were acquired by the Varian Truebeam treatment system. Set-up errors were evaluated by radiation oncologists, after CBCT correction. The clinical target volume (CTV) was delineated on each CBCT, and the planning target volume (PTV) coverage of each CBCT-CTVs was analyzed. Results: A total of 152 CBCT scans were acquired from twenty cervical cancer patients, the mean set-up errors in the longitudinal, vertical, and lateral direction were 3.57, 2.74 and 2.5mm respectively, without CBCT corrections. After corrections, these were decreased to 1.83, 1.44 and 0.97mm. For the target coverage, CBCT-CTV coverage without CBCT correction was 94% (143/152), and 98% (149/152) with correction. Conclusion: Use of CBCT verfication to measure patient setup errors could be applied to improve the treatment accuracy. In addition, the set-up error corrections significantly improve the CTV coverage for cervical cancer patients.

  3. Tomography

    International Nuclear Information System (INIS)

    Brown, B.H.; Barber, D.C.; Freeston, I.L.

    1983-01-01

    Tomography images of a body are constructed by placing a plurality of surface electrodes at spaced intervals on the body, causing currents to flow in the body (e.g. by applying a potential between each pair of electrodes in turn, or by induction), and measuring the potential between pairs of electrodes, calculating the potential expected in each case on the assumption that the body consists of a medium of uniform impedance, plotting the isopotentials corresponding to the calculated results to create a uniform image of the body, obtaining the ratio between the measured potential and the calculated potential in each case, and modifying the image in accordance with the respective ratios by increasing the assumed impedance along an isopotential in proportion to a ratio greater than unity or decreasing the assumed impedance in proportion to a ratio less than unity. The modified impedances along the isopotentials for each pair of electrodes are superimposed. The calculations are carried out using a computer and the plotting is carried out by a visual display unit and/or a print-out unit. (author)

  4. Error analysis of the freshmen Criminology students’ grammar in the written English

    Directory of Open Access Journals (Sweden)

    Maico Demi Banate Aperocho

    2017-12-01

    Full Text Available This study identifies the various syntactical errors of the fifty (50 freshmen B.S. Criminology students of the University of Mindanao in Davao City. Specifically, this study aims to answer the following: (1 What are the common errors present in the argumentative essays of the respondents? (2 What are the reasons of the existence of these errors? This study is descriptive-qualitative. It also uses error analysis to point out the syntactical errors present in the compositions of the participants. The fifty essays are subjected to error analysis. Errors are classified based on Chanquoy’s Classification of Writing Errors. Furthermore, Hourani’s Common Reasons of Grammatical Errors Checklist was also used to determine the common reasons of the identified syntactical errors. To create a meaningful interpretation of data and to solicit further ideas from the participants, a focus group discussion is also done. Findings show that students’ most common errors are on the grammatical aspect. In the grammatical aspect, students have more frequently committed errors in the verb aspect (tense, subject agreement, and auxiliary and linker choice compared to spelling and punctuation aspects. Moreover, there are three topmost reasons of committing errors in the paragraph: mother tongue interference, incomprehensibility of the grammar rules, and the incomprehensibility of the writing mechanics. Despite the difficulty in learning English as a second language, students are still very motivated to master the concepts and applications of the language.

  5. Error analysis in predictive modelling demonstrated on mould data.

    Science.gov (United States)

    Baranyi, József; Csernus, Olívia; Beczner, Judit

    2014-01-17

    The purpose of this paper was to develop a predictive model for the effect of temperature and water activity on the growth rate of Aspergillus niger and to determine the sources of the error when the model is used for prediction. Parallel mould growth curves, derived from the same spore batch, were generated and fitted to determine their growth rate. The variances of replicate ln(growth-rate) estimates were used to quantify the experimental variability, inherent to the method of determining the growth rate. The environmental variability was quantified by the variance of the respective means of replicates. The idea is analogous to the "within group" and "between groups" variability concepts of ANOVA procedures. A (secondary) model, with temperature and water activity as explanatory variables, was fitted to the natural logarithm of the growth rates determined by the primary model. The model error and the experimental and environmental errors were ranked according to their contribution to the total error of prediction. Our method can readily be applied to analysing the error structure of predictive models of bacterial growth models, too. © 2013.

  6. Development of an analysis rule of diagnosis error for standard method of human reliability analysis

    International Nuclear Information System (INIS)

    Jeong, W. D.; Kang, D. I.; Jeong, K. S.

    2003-01-01

    This paper presents the status of development of Korea standard method for Human Reliability Analysis (HRA), and proposed a standard procedure and rules for the evaluation of diagnosis error probability. The quality of KSNP HRA was evaluated using the requirement of ASME PRA standard guideline, and the design requirement for the standard HRA method was defined. Analysis procedure and rules, developed so far, to analyze diagnosis error probability was suggested as a part of the standard method. And also a study of comprehensive application was performed to evaluate the suitability of the proposed rules

  7. Segmentation error and macular thickness measurements obtained with spectral-domain optical coherence tomography devices in neovascular age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Moosang Kim

    2013-01-01

    Full Text Available Purpose: To evaluate frequency and severity of segmentation errors of two spectral-domain optical coherence tomography (SD-OCT devices and error effect on central macular thickness (CMT measurements. Materials and Methods: Twenty-seven eyes of 25 patients with neovascular age-related macular degeneration, examined using the Cirrus HD-OCT and Spectralis HRA + OCT, were retrospectively reviewed. Macular cube 512 × 128 and 5-line raster scans were performed with the Cirrus and 512 × 25 volume scans with the Spectralis. Frequency and severity of segmentation errors were compared between scans. Results: Segmentation error frequency was 47.4% (baseline, 40.7% (1 month, 40.7% (2 months, and 48.1% (6 months for the Cirrus, and 59.3%, 62.2%, 57.8%, and 63.7%, respectively, for the Spectralis, differing significantly between devices at all examinations (P < 0.05, except at baseline. Average error score was 1.21 ± 1.65 (baseline, 0.79 ± 1.18 (1 month, 0.74 ± 1.12 (2 months, and 0.96 ± 1.11 (6 months for the Cirrus, and 1.73 ± 1.50, 1.54 ± 1.35, 1.38 ± 1.40, and 1.49 ± 1.30, respectively, for the Spectralis, differing significantly at 1 month and 2 months (P < 0.02. Automated and manual CMT measurements by the Spectralis were larger than those by the Cirrus. Conclusions: The Cirrus HD-OCT had a lower frequency and severity of segmentation error than the Spectralis HRA + OCT. SD-OCT error should be considered when evaluating retinal thickness.

  8. EEL spectroscopic tomography: towards a new dimension in nanomaterials analysis.

    Science.gov (United States)

    Yedra, Lluís; Eljarrat, Alberto; Arenal, Raúl; Pellicer, Eva; Cabo, Moisés; López-Ortega, Alberto; Estrader, Marta; Sort, Jordi; Baró, Maria Dolors; Estradé, Sònia; Peiró, Francesca

    2012-11-01

    Electron tomography is a widely spread technique for recovering the three dimensional (3D) shape of nanostructured materials. Using a spectroscopic signal to achieve a reconstruction adds a fourth chemical dimension to the 3D structure. Up to date, energy filtering of the images in the transmission electron microscope (EFTEM) is the usual spectroscopic method even if most of the information in the spectrum is lost. Unlike EFTEM tomography, the use of electron energy-loss spectroscopy (EELS) spectrum images (SI) for tomographic reconstruction retains all chemical information, and the possibilities of this new approach still remain to be fully exploited. In this article we prove the feasibility of EEL spectroscopic tomography at low voltages (80 kV) and short acquisition times from data acquired using an aberration corrected instrument and data treatment by Multivariate Analysis (MVA), applied to Fe(x)Co((3-x))O(4)@Co(3)O(4) mesoporous materials. This approach provides a new scope into materials; the recovery of full EELS signal in 3D. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Towards adaptive, streaming analysis of x-ray tomography data

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Mathew; Kleese van Dam, Kerstin; Marshall, Matthew J.; Kuprat, Andrew P.; Carson, James P.; Lansing, Carina S.; Guillen, Zoe C.; Miller, Erin A.; Lanekoff, Ingela; Laskin, Julia

    2015-03-04

    Temporal and spatial resolution of chemical imaging methodologies such as x-ray tomography are rapidly increasing, leading to more complex experimental procedures and fast growing data volumes. Automated analysis pipelines and big data analytics are becoming essential to effectively evaluate the results of such experiments. Offering those data techniques in an adaptive, streaming environment can further substantially improve the scientific discovery process, by enabling experimental control and steering based on the evaluation of emerging phenomena as they are observed by the experiment. Pacific Northwest National Laboratory (PNNL)’ Chemical Imaging Initiative (CII - http://imaging.pnnl.gov/ ) has worked since 2011 towards developing a framework that allows users to rapidly compose and customize high throughput experimental analysis pipelines for multiple instrument types. The framework, named ‘Rapid Experimental Analysis’ (REXAN) Framework [1], is based on the idea of reusable component libraries and utilizes the PNNL developed collaborative data management and analysis environment ‘Velo’, to provide a user friendly analysis and data management environment for experimental facilities. This article will, discuss the capabilities established for X-Ray tomography, discuss lessons learned, and provide an overview of our more recent work in the Analysis in Motion Initiative (AIM - http://aim.pnnl.gov/ ) at PNNL to provide REXAN capabilities in a streaming environment.

  10. Analysis and improvement of gas turbine blade temperature measurement error

    International Nuclear Information System (INIS)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-01-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed. (paper)

  11. Analysis and improvement of gas turbine blade temperature measurement error

    Science.gov (United States)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-10-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

  12. Undesirable effects of covariance matrix techniques for error analysis

    International Nuclear Information System (INIS)

    Seibert, D.

    1994-01-01

    Regression with χ 2 constructed from covariance matrices should not be used for some combinations of covariance matrices and fitting functions. Using the technique for unsuitable combinations can amplify systematic errors. This amplification is uncontrolled, and can produce arbitrarily inaccurate results that might not be ruled out by a χ 2 test. In addition, this technique can give incorrect (artificially small) errors for fit parameters. I give a test for this instability and a more robust (but computationally more intensive) method for fitting correlated data

  13. An advanced human reliability analysis methodology: analysis of cognitive errors focused on

    International Nuclear Information System (INIS)

    Kim, J. H.; Jeong, W. D.

    2001-01-01

    The conventional Human Reliability Analysis (HRA) methods such as THERP/ASEP, HCR and SLIM has been criticised for their deficiency in analysing cognitive errors which occurs during operator's decision making process. In order to supplement the limitation of the conventional methods, an advanced HRA method, what is called the 2 nd generation HRA method, including both qualitative analysis and quantitative assessment of cognitive errors has been being developed based on the state-of-the-art theory of cognitive systems engineering and error psychology. The method was developed on the basis of human decision-making model and the relation between the cognitive function and the performance influencing factors. The application of the proposed method to two emergency operation tasks is presented

  14. Creating a Multi-material Probing Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems

    DEFF Research Database (Denmark)

    Borges de Oliveira, Fabrício; Stolfi, Alessandro; Bartscher, Markus

    2017-01-01

    The requirement of quality assurance of inner and outer structures in complex multi-material assemblies is one important factor that has encouraged the use of industrial X-ray computed tomography (CT). The application of CT as a coordinate measurement system (CMS) has opened up new challenges...

  15. Human error in strabismus surgery: Quantification with a sensitivity analysis

    NARCIS (Netherlands)

    S. Schutte (Sander); J.R. Polling (Jan Roelof); F.C.T. van der Helm (Frans); H.J. Simonsz (Huib)

    2009-01-01

    textabstractBackground: Reoperations are frequently necessary in strabismus surgery. The goal of this study was to analyze human-error related factors that introduce variability in the results of strabismus surgery in a systematic fashion. Methods: We identified the primary factors that influence

  16. Human error in strabismus surgery : Quantification with a sensitivity analysis

    NARCIS (Netherlands)

    Schutte, S.; Polling, J.R.; Van der Helm, F.C.T.; Simonsz, H.J.

    2008-01-01

    Background- Reoperations are frequently necessary in strabismus surgery. The goal of this study was to analyze human-error related factors that introduce variability in the results of strabismus surgery in a systematic fashion. Methods- We identified the primary factors that influence the outcome of

  17. Linguistic Error Analysis on Students' Thesis Proposals

    Science.gov (United States)

    Pescante-Malimas, Mary Ann; Samson, Sonrisa C.

    2017-01-01

    This study identified and analyzed the common linguistic errors encountered by Linguistics, Literature, and Advertising Arts majors in their Thesis Proposal classes in the First Semester 2016-2017. The data were the drafts of the thesis proposals of the students from the three different programs. A total of 32 manuscripts were analyzed which was…

  18. Reading and Spelling Error Analysis of Native Arabic Dyslexic Readers

    Science.gov (United States)

    Abu-rabia, Salim; Taha, Haitham

    2004-01-01

    This study was an investigation of reading and spelling errors of dyslexic Arabic readers ("n"=20) compared with two groups of normal readers: a young readers group, matched with the dyslexics by reading level ("n"=20) and an age-matched group ("n"=20). They were tested on reading and spelling of texts, isolated…

  19. Analysis of Students' Error in Learning of Quadratic Equations

    Science.gov (United States)

    Zakaria, Effandi; Ibrahim; Maat, Siti Mistima

    2010-01-01

    The purpose of the study was to determine the students' error in learning quadratic equation. The samples were 30 form three students from a secondary school in Jambi, Indonesia. Diagnostic test was used as the instrument of this study that included three components: factorization, completing the square and quadratic formula. Diagnostic interview…

  20. Analysis of Daily Setup Variation With Tomotherapy Megavoltage Computed Tomography

    International Nuclear Information System (INIS)

    Zhou Jining; Uhl, Barry; Dewit, Kelly; Young, Mark; Taylor, Brian; Fei Dingyu; Lo, Y-C

    2010-01-01

    The purpose of this study was to evaluate different setup uncertainties for various anatomic sites with TomoTherapy (registered) pretreatment megavoltage computed tomography (MVCT) and to provide optimal margin guidelines for these anatomic sites. Ninety-two patients with tumors in head and neck (HN), brain, lung, abdominal, or prostate regions were included in the study. MVCT was used to verify patient position and tumor target localization before each treatment. With the anatomy registration tool, MVCT provided real-time tumor shift coordinates relative to the positions where the simulation CT was performed. Thermoplastic facemasks were used for HN and brain treatments. Vac-Lok TM cushions were used to immobilize the lower extremities up to the thighs for prostate patients. No respiration suppression was administered for lung and abdomen patients. The interfractional setup variations were recorded and corrected before treatment. The mean interfractional setup error was the smallest for HN among the 5 sites analyzed. The average 3D displacement in lateral, longitudinal, and vertical directions for the 5 sites ranged from 2.2-7.7 mm for HN and lung, respectively. The largest movement in the lung was 2.0 cm in the longitudinal direction, with a mean error of 6.0 mm and standard deviation of 4.8 mm. The mean interfractional rotation variation was small and ranged from 0.2-0.5 deg., with the standard deviation ranging from 0.7-0.9 deg. Internal organ displacement was also investigated with a posttreatment MVCT scan for HN, lung, abdomen, and prostate patients. The maximum 3D intrafractional displacement across all sites was less than 4.5 mm. The interfractional systematic errors and random errors were analyzed and the suggested margins for HN, brain, prostate, abdomen, and lung in the lateral, longitudinal, and vertical directions were between 4.2 and 8.2 mm, 5.0 mm and 12.0 mm, and 1.5 mm and 6.8 mm, respectively. We suggest that TomoTherapy (registered) pretreatment

  1. Analysis of daily setup variation with tomotherapy megavoltage computed tomography.

    Science.gov (United States)

    Zhou, Jining; Uhl, Barry; Dewit, Kelly; Young, Mark; Taylor, Brian; Fei, Ding-Yu; Lo, Yeh-Chi

    2010-01-01

    The purpose of this study was to evaluate different setup uncertainties for various anatomic sites with TomoTherapy pretreatment megavoltage computed tomography (MVCT) and to provide optimal margin guidelines for these anatomic sites. Ninety-two patients with tumors in head and neck (HN), brain, lung, abdominal, or prostate regions were included in the study. MVCT was used to verify patient position and tumor target localization before each treatment. With the anatomy registration tool, MVCT provided real-time tumor shift coordinates relative to the positions where the simulation CT was performed. Thermoplastic facemasks were used for HN and brain treatments. Vac-Lok cushions were used to immobilize the lower extremities up to the thighs for prostate patients. No respiration suppression was administered for lung and abdomen patients. The interfractional setup variations were recorded and corrected before treatment. The mean interfractional setup error was the smallest for HN among the 5 sites analyzed. The average 3D displacement in lateral, longitudinal, and vertical directions for the 5 sites ranged from 2.2-7.7 mm for HN and lung, respectively. The largest movement in the lung was 2.0 cm in the longitudinal direction, with a mean error of 6.0 mm and standard deviation of 4.8 mm. The mean interfractional rotation variation was small and ranged from 0.2-0.5 degrees, with the standard deviation ranging from 0.7-0.9 degrees. Internal organ displacement was also investigated with a posttreatment MVCT scan for HN, lung, abdomen, and prostate patients. The maximum 3D intrafractional displacement across all sites was less than 4.5 mm. The interfractional systematic errors and random errors were analyzed and the suggested margins for HN, brain, prostate, abdomen, and lung in the lateral, longitudinal, and vertical directions were between 4.2 and 8.2 mm, 5.0 mm and 12.0 mm, and 1.5 mm and 6.8 mm, respectively. We suggest that TomoTherapy pretreatment MVCT can be used to

  2. Computer Tomography Analysis of Fastrac Composite Thrust Chamber Assemblies

    Science.gov (United States)

    Beshears, Ronald D.

    2000-01-01

    Computed tomography (CT) inspection has been integrated into the production process for NASA's Fastrac composite thrust chamber assemblies (TCAs). CT has been proven to be uniquely qualified to detect the known critical flaw for these nozzles, liner cracks that are adjacent to debonds between the liner and overwrap. CT is also being used as a process monitoring tool through analysis of low density indications in the nozzle overwraps. 3d reconstruction of CT images to produce models of flawed areas is being used to give program engineers better insight into the location and nature of nozzle flaws.

  3. SU-F-T-320: Assessing Placement Error of Optically Stimulated Luminescent in Vivo Dosimeters Using Cone-Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Riegel, A; Klein, E [Northwell Health, Lake Success, NY (United States); Tariq, M; Gomez, C [Hofstra University, Hempstead, NY (United States)

    2016-06-15

    Purpose: Optically-stimulated luminescent dosimeters (OSLDs) are increasingly utilized for in vivo dosimetry of complex radiation delivery techniques such as intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Evaluation of clinical uncertainties such as placement error has not been performed. This work retrospectively investigates the magnitude of placement error using conebeam computed tomography (CBCT) and its effect on measured/planned dose agreement. Methods: Each OSLD was placed at a physicist-designated location on the patient surface on a weekly basis. The location was given in terms of a gantry angle and two-dimensional offset from central axis. The OSLDs were placed before daily image guidance. We identified 77 CBCTs from 25 head-and-neck patients who received IMRT or VMAT, where OSLDs were visible on the CT image. Grossly misplaced OSLDs were excluded (e.g. wrong laterality). CBCTs were registered with the treatment plan and the distance between the planned and actual OSLD location was calculated in two dimensions in the beam’s eye view. Distances were correlated with measured/planned dose percent differences. Results: OSLDs were grossly misplaced for 5 CBCTs (6.4%). For the remaining 72 CBCTs, average placement error was 7.0±6.0 mm. These errors were not correlated with measured/planned dose percent differences (R{sup 2}=0.0153). Generalizing the dosimetric effect of placement errors may be unreliable. Conclusion: Correct placement of OSLDs for IMRT and VMAT treatments is critical to accurate and precise in vivo dosimetry. Small placement errors could produce large disagreement between measured and planned dose. Further work includes expansion to other treatment sites, examination of planned dose at the actual point of OSLD placement, and the influence of imageguided shifts on measured/planned dose agreement.

  4. Spatial-temporal analysis of wind power forecast errors for West-Coast Norway

    Energy Technology Data Exchange (ETDEWEB)

    Revheim, Paal Preede; Beyer, Hans Georg [Agder Univ. (UiA), Grimstad (Norway). Dept. of Engineering Sciences

    2012-07-01

    In this paper the spatial-temporal structure of forecast errors for wind power in West-Coast Norway is analyzed. Starting on the qualitative analysis of the forecast error reduction, with respect to single site data, for the lumped conditions of groups of sites the spatial and temporal correlations of the wind power forecast errors within and between the same groups are studied in detail. Based on this, time-series regression models to be used to analytically describe the error reduction are set up. The models give an expected reduction in forecast error between 48.4% and 49%. (orig.)

  5. Dynamic Error Analysis Method for Vibration Shape Reconstruction of Smart FBG Plate Structure

    Directory of Open Access Journals (Sweden)

    Hesheng Zhang

    2016-01-01

    Full Text Available Shape reconstruction of aerospace plate structure is an important issue for safe operation of aerospace vehicles. One way to achieve such reconstruction is by constructing smart fiber Bragg grating (FBG plate structure with discrete distributed FBG sensor arrays using reconstruction algorithms in which error analysis of reconstruction algorithm is a key link. Considering that traditional error analysis methods can only deal with static data, a new dynamic data error analysis method are proposed based on LMS algorithm for shape reconstruction of smart FBG plate structure. Firstly, smart FBG structure and orthogonal curved network based reconstruction method is introduced. Then, a dynamic error analysis model is proposed for dynamic reconstruction error analysis. Thirdly, the parameter identification is done for the proposed dynamic error analysis model based on least mean square (LMS algorithm. Finally, an experimental verification platform is constructed and experimental dynamic reconstruction analysis is done. Experimental results show that the dynamic characteristics of the reconstruction performance for plate structure can be obtained accurately based on the proposed dynamic error analysis method. The proposed method can also be used for other data acquisition systems and data processing systems as a general error analysis method.

  6. The application of two recently developed human reliability techniques to cognitive error analysis

    International Nuclear Information System (INIS)

    Gall, W.

    1990-01-01

    Cognitive error can lead to catastrophic consequences for manned systems, including those whose design renders them immune to the effects of physical slips made by operators. Four such events, pressurized water and boiling water reactor accidents which occurred recently, were analysed. The analysis identifies the factors which contributed to the errors and suggests practical strategies for error recovery or prevention. Two types of analysis were conducted: an unstructured analysis based on the analyst's knowledge of psychological theory, and a structured analysis using two recently-developed human reliability analysis techniques. In general, the structured techniques required less effort to produce results and these were comparable to those of the unstructured analysis. (author)

  7. Error analysis of terrestrial laser scanning data by means of spherical statistics and 3D graphs.

    Science.gov (United States)

    Cuartero, Aurora; Armesto, Julia; Rodríguez, Pablo G; Arias, Pedro

    2010-01-01

    This paper presents a complete analysis of the positional errors of terrestrial laser scanning (TLS) data based on spherical statistics and 3D graphs. Spherical statistics are preferred because of the 3D vectorial nature of the spatial error. Error vectors have three metric elements (one module and two angles) that were analyzed by spherical statistics. A study case has been presented and discussed in detail. Errors were calculating using 53 check points (CP) and CP coordinates were measured by a digitizer with submillimetre accuracy. The positional accuracy was analyzed by both the conventional method (modular errors analysis) and the proposed method (angular errors analysis) by 3D graphics and numerical spherical statistics. Two packages in R programming language were performed to obtain graphics automatically. The results indicated that the proposed method is advantageous as it offers a more complete analysis of the positional accuracy, such as angular error component, uniformity of the vector distribution, error isotropy, and error, in addition the modular error component by linear statistics.

  8. Spectral Analysis of Forecast Error Investigated with an Observing System Simulation Experiment

    Science.gov (United States)

    Prive, N. C.; Errico, Ronald M.

    2015-01-01

    The spectra of analysis and forecast error are examined using the observing system simulation experiment (OSSE) framework developed at the National Aeronautics and Space Administration Global Modeling and Assimilation Office (NASAGMAO). A global numerical weather prediction model, the Global Earth Observing System version 5 (GEOS-5) with Gridpoint Statistical Interpolation (GSI) data assimilation, is cycled for two months with once-daily forecasts to 336 hours to generate a control case. Verification of forecast errors using the Nature Run as truth is compared with verification of forecast errors using self-analysis; significant underestimation of forecast errors is seen using self-analysis verification for up to 48 hours. Likewise, self analysis verification significantly overestimates the error growth rates of the early forecast, as well as mischaracterizing the spatial scales at which the strongest growth occurs. The Nature Run-verified error variances exhibit a complicated progression of growth, particularly for low wave number errors. In a second experiment, cycling of the model and data assimilation over the same period is repeated, but using synthetic observations with different explicitly added observation errors having the same error variances as the control experiment, thus creating a different realization of the control. The forecast errors of the two experiments become more correlated during the early forecast period, with correlations increasing for up to 72 hours before beginning to decrease.

  9. DOI resolution measurement and error analysis with LYSO and APDs

    International Nuclear Information System (INIS)

    Lee, Chae-hun; Cho, Gyuseong

    2008-01-01

    Spatial resolution degradation in PET occurs at the edge of Field Of View (FOV) due to parallax error. To improve spatial resolution at the edge of FOV, Depth-Of-Interaction (DOI) PET has been investigated and several methods for DOI positioning were proposed. In this paper, a DOI-PET detector module using two 8x4 array avalanche photodiodes (APDs) (Hamamatsu, S8550) and a 2 cm long LYSO scintillation crystal was proposed and its DOI characteristics were investigated experimentally. In order to measure DOI positions, signals from two APDs were compared. Energy resolution was obtained from the sum of two APDs' signals and DOI positioning error was calculated. Finally, an optimum DOI step size in a 2 cm long LYSO were suggested to help to design a DOI-PET

  10. Time Error Analysis of SOE System Using Network Time Protocol

    International Nuclear Information System (INIS)

    Keum, Jong Yong; Park, Geun Ok; Park, Heui Youn

    2005-01-01

    To find the accuracy of time in the fully digitalized SOE (Sequence of Events) system, we used a formal specification of the Network Time Protocol (NTP) Version 3, which is used to synchronize time keeping among a set of distributed computers. Through constructing a simple experimental environments and experimenting internet time synchronization, we analyzed the time errors of local clocks of SOE system synchronized with a time server via computer networks

  11. Error analysis of pupils in calculating with fractions

    OpenAIRE

    Uranič, Petra

    2016-01-01

    In this thesis I examine the correlation between the frequency of errors that seventh grade pupils make in their calculations with fractions and their level of understanding of fractions. Fractions are a relevant and demanding theme in the mathematics curriculum. Although we use fractions on a daily basis, pupils find learning fractions to be very difficult. They generally do not struggle with the concept of fractions itself, but they frequently have problems with mathematical operations ...

  12. Magnetic error analysis of recycler pbar injection transfer line

    Energy Technology Data Exchange (ETDEWEB)

    Yang, M.J.; /Fermilab

    2007-06-01

    Detailed study of Fermilab Recycler Ring anti-proton injection line became feasible with its BPM system upgrade, though the beamline has been in existence and operational since year 2000. Previous attempts were not fruitful due to limitations in the BPM system. Among the objectives are the assessment of beamline optics and the presence of error fields. In particular the field region of the permanent Lambertson magnets at both ends of R22 transfer line will be scrutinized.

  13. Analysis of Periodic Errors for Synthesized-Reference-Wave Holography

    Directory of Open Access Journals (Sweden)

    V. Schejbal

    2009-12-01

    Full Text Available Synthesized-reference-wave holographic techniques offer relatively simple and cost-effective measurement of antenna radiation characteristics and reconstruction of complex aperture fields using near-field intensity-pattern measurement. These methods allow utilization of advantages of methods for probe compensations for amplitude and phasing near-field measurements for the planar and cylindrical scanning including accuracy analyses. The paper analyzes periodic errors, which can be created during scanning, using both theoretical results and numerical simulations.

  14. Slow Learner Errors Analysis in Solving Fractions Problems in Inclusive Junior High School Class

    Science.gov (United States)

    Novitasari, N.; Lukito, A.; Ekawati, R.

    2018-01-01

    A slow learner whose IQ is between 71 and 89 will have difficulties in solving mathematics problems that often lead to errors. The errors could be analyzed to where the errors may occur and its type. This research is qualitative descriptive which aims to describe the locations, types, and causes of slow learner errors in the inclusive junior high school class in solving the fraction problem. The subject of this research is one slow learner of seventh-grade student which was selected through direct observation by the researcher and through discussion with mathematics teacher and special tutor which handles the slow learner students. Data collection methods used in this study are written tasks and semistructured interviews. The collected data was analyzed by Newman’s Error Analysis (NEA). Results show that there are four locations of errors, namely comprehension, transformation, process skills, and encoding errors. There are four types of errors, such as concept, principle, algorithm, and counting errors. The results of this error analysis will help teachers to identify the causes of the errors made by the slow learner.

  15. Positron emission tomography: Physics, instrumentation, and image analysis

    International Nuclear Information System (INIS)

    Porenta, G.

    1994-01-01

    Positron emission tomography (PET) is a noninvasive diagnostic technique that permits reconstruction of cross-sectional images of the human body which depict the biodistribution of PET tracer substances. A large variety of physiological PET tracers, mostly based on isotopes of carbon, nitrogen, oxygen, and fluorine is available and allows the in vivo investigation of organ perfusion, metabolic pathways and biomolecular processes in normal and diseased states. PET cameras utilize the physical characteristics of positron decay to derive quantitative measurements of tracer concentrations, a capability that has so far been elusive for conventional SPECT (single photon emission computed tomography) imaging techniques. Due to the short half lives of most PET isotopes, an on-site cyclotron and a radiochemistry unit are necessary to provide an adequate supply of PET tracers. While operating a PET center in the past was a complex procedure restricted to few academic centers with ample resources. PET technology has rapidly advanced in recent years and has entered the commercial nuclear medicine market. To date, the availability of compact cyclotrons with remote computer control, automated synthesis units for PET radiochemistry, high-performance PET cameras, and userfriendly analysis workstations permits installation of a clinical PET center within most nuclear medicine facilities. This review provides simple descriptions of important aspects concerning physics, instrumentation, and image analysis in PET imaging which should be understood by medical personnel involved in the clinical operation of a PET imaging center. (author)

  16. A methodology for collection and analysis of human error data based on a cognitive model: IDA

    International Nuclear Information System (INIS)

    Shen, S.-H.; Smidts, C.; Mosleh, A.

    1997-01-01

    This paper presents a model-based human error taxonomy and data collection. The underlying model, IDA (described in two companion papers), is a cognitive model of behavior developed for analysis of the actions of nuclear power plant operating crew during abnormal situations. The taxonomy is established with reference to three external reference points (i.e. plant status, procedures, and crew) and four reference points internal to the model (i.e. information collected, diagnosis, decision, action). The taxonomy helps the analyst: (1) recognize errors as such; (2) categorize the error in terms of generic characteristics such as 'error in selection of problem solving strategies' and (3) identify the root causes of the error. The data collection methodology is summarized in post event operator interview and analysis summary forms. The root cause analysis methodology is illustrated using a subset of an actual event. Statistics, which extract generic characteristics of error prone behaviors and error prone situations are presented. Finally, applications of the human error data collection are reviewed. A primary benefit of this methodology is to define better symptom-based and other auxiliary procedures with associated training to minimize or preclude certain human errors. It also helps in design of control rooms, and in assessment of human error probabilities in the probabilistic risk assessment framework. (orig.)

  17. Analysis of Human Error Types and Performance Shaping Factors in the Next Generation Main Control Room

    International Nuclear Information System (INIS)

    Sin, Y. C.; Jung, Y. S.; Kim, K. H.; Kim, J. H.

    2008-04-01

    Main control room of nuclear power plants has been computerized and digitalized in new and modernized plants, as information and digital technologies make great progresses and become mature. Survey on human factors engineering issues in advanced MCRs: Model-based approach, Literature survey-based approach. Analysis of human error types and performance shaping factors is analysis of three human errors. The results of project can be used for task analysis, evaluation of human error probabilities, and analysis of performance shaping factors in the HRA analysis

  18. AN ERROR ANALYSIS OF ARGUMENTATIVE ESSAY (CASE STUDY AT UNIVERSITY MUHAMMADIYAH OF METRO

    Directory of Open Access Journals (Sweden)

    Fenny - Thresia

    2015-10-01

    Full Text Available The purpose of this study was study analyze the students’ error in writing argumentative essay. The researcher focuses on errors of verb, concord and learner language. This study took 20 students as the subject of research from the third semester. The data took from observation and documentation. Based on the result of the data analysis there are some errors still found on the student’s argumentative essay in English writing? The common errors which repeatedly appear are verb. The second is concord, and learner languages are the smallest error. From 20 samples that took, the frequency the errors of verb are 12 items (60%, concord are 8 items (40%, learner languages are 7 items (35%. As a result, verb has the biggest number of common errors.

  19. ERROR ANALYSIS IN THE TRAVEL WRITING MADE BY THE STUDENTS OF ENGLISH STUDY PROGRAM

    Directory of Open Access Journals (Sweden)

    Vika Agustina

    2015-05-01

    Full Text Available This study was conducted to identify the kinds of errors in surface strategy taxonomy and to know the dominant type of errors made by the fifth semester students of English Department of one State University in Malang-Indonesia in producing their travel writing. The type of research of this study is document analysis since it analyses written materials, in this case travel writing texts. The analysis finds that the grammatical errors made by the students based on surface strategy taxonomy theory consist of four types. They are (1 omission, (2 addition, (3 misformation and (4 misordering. The most frequent errors occuring in misformation are in the use of tense form. Secondly, the errors are in omission of noun/verb inflection. The next error, there are many clauses that contain unnecessary phrase added there.

  20. Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure Channels

    DEFF Research Database (Denmark)

    Ivanov, Mikhail; Graell i Amat, Alexandre; Brannstrom, F.

    2014-01-01

    We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore ...... identify the most dominant stopping sets for the distributions of practical interest. The derived analytical expressions allow us to accurately predict the error floor at low to moderate channel loads and characterize the unequal error protection inherent in CSA.......We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore...

  1. Analysis of Student Errors on Division of Fractions

    Science.gov (United States)

    Maelasari, E.; Jupri, A.

    2017-02-01

    This study aims to describe the type of student errors that typically occurs at the completion of the division arithmetic operations on fractions, and to describe the causes of students’ mistakes. This research used a descriptive qualitative method, and involved 22 fifth grade students at one particular elementary school in Kuningan, Indonesia. The results of this study showed that students’ error answers caused by students changing their way of thinking to solve multiplication and division operations on the same procedures, the changing of mix fractions to common fraction have made students confused, and students are careless in doing calculation. From student written work, in solving the fraction problems, we found that there is influence between the uses of learning methods and student response, and some of student responses beyond researchers’ prediction. We conclude that the teaching method is not only the important thing that must be prepared, but the teacher should also prepare about predictions of students’ answers to the problems that will be given in the learning process. This could be a reflection for teachers to be better and to achieve the expected learning goals.

  2. Error Probability Analysis of Hardware Impaired Systems with Asymmetric Transmission

    KAUST Repository

    Javed, Sidrah; Amin, Osama; Ikki, Salama S.; Alouini, Mohamed-Slim

    2018-01-01

    Error probability study of the hardware impaired (HWI) systems highly depends on the adopted model. Recent models have proved that the aggregate noise is equivalent to improper Gaussian signals. Therefore, considering the distinct noise nature and self-interfering (SI) signals, an optimal maximum likelihood (ML) receiver is derived. This renders the conventional minimum Euclidean distance (MED) receiver as a sub-optimal receiver because it is based on the assumptions of ideal hardware transceivers and proper Gaussian noise in communication systems. Next, the average error probability performance of the proposed optimal ML receiver is analyzed and tight bounds and approximations are derived for various adopted systems including transmitter and receiver I/Q imbalanced systems with or without transmitter distortions as well as transmitter or receiver only impaired systems. Motivated by recent studies that shed the light on the benefit of improper Gaussian signaling in mitigating the HWIs, asymmetric quadrature amplitude modulation or phase shift keying is optimized and adapted for transmission. Finally, different numerical and simulation results are presented to support the superiority of the proposed ML receiver over MED receiver, the tightness of the derived bounds and effectiveness of asymmetric transmission in dampening HWIs and improving overall system performance

  3. Error Probability Analysis of Hardware Impaired Systems with Asymmetric Transmission

    KAUST Repository

    Javed, Sidrah

    2018-04-26

    Error probability study of the hardware impaired (HWI) systems highly depends on the adopted model. Recent models have proved that the aggregate noise is equivalent to improper Gaussian signals. Therefore, considering the distinct noise nature and self-interfering (SI) signals, an optimal maximum likelihood (ML) receiver is derived. This renders the conventional minimum Euclidean distance (MED) receiver as a sub-optimal receiver because it is based on the assumptions of ideal hardware transceivers and proper Gaussian noise in communication systems. Next, the average error probability performance of the proposed optimal ML receiver is analyzed and tight bounds and approximations are derived for various adopted systems including transmitter and receiver I/Q imbalanced systems with or without transmitter distortions as well as transmitter or receiver only impaired systems. Motivated by recent studies that shed the light on the benefit of improper Gaussian signaling in mitigating the HWIs, asymmetric quadrature amplitude modulation or phase shift keying is optimized and adapted for transmission. Finally, different numerical and simulation results are presented to support the superiority of the proposed ML receiver over MED receiver, the tightness of the derived bounds and effectiveness of asymmetric transmission in dampening HWIs and improving overall system performance

  4. Patient safety in the clinical laboratory: a longitudinal analysis of specimen identification errors.

    Science.gov (United States)

    Wagar, Elizabeth A; Tamashiro, Lorraine; Yasin, Bushra; Hilborne, Lee; Bruckner, David A

    2006-11-01

    Patient safety is an increasingly visible and important mission for clinical laboratories. Attention to improving processes related to patient identification and specimen labeling is being paid by accreditation and regulatory organizations because errors in these areas that jeopardize patient safety are common and avoidable through improvement in the total testing process. To assess patient identification and specimen labeling improvement after multiple implementation projects using longitudinal statistical tools. Specimen errors were categorized by a multidisciplinary health care team. Patient identification errors were grouped into 3 categories: (1) specimen/requisition mismatch, (2) unlabeled specimens, and (3) mislabeled specimens. Specimens with these types of identification errors were compared preimplementation and postimplementation for 3 patient safety projects: (1) reorganization of phlebotomy (4 months); (2) introduction of an electronic event reporting system (10 months); and (3) activation of an automated processing system (14 months) for a 24-month period, using trend analysis and Student t test statistics. Of 16,632 total specimen errors, mislabeled specimens, requisition mismatches, and unlabeled specimens represented 1.0%, 6.3%, and 4.6% of errors, respectively. Student t test showed a significant decrease in the most serious error, mislabeled specimens (P patient safety projects. Trend analysis demonstrated decreases in all 3 error types for 26 months. Applying performance-improvement strategies that focus longitudinally on specimen labeling errors can significantly reduce errors, therefore improving patient safety. This is an important area in which laboratory professionals, working in interdisciplinary teams, can improve safety and outcomes of care.

  5. Encapsulation method for atom probe tomography analysis of nanoparticles

    International Nuclear Information System (INIS)

    Larson, D.J.; Giddings, A.D.; Wu, Y.; Verheijen, M.A.; Prosa, T.J.; Roozeboom, F.; Rice, K.P.; Kessels, W.M.M.; Geiser, B.P.; Kelly, T.F.

    2015-01-01

    Open-space nanomaterials are a widespread class of technologically important materials that are generally incompatible with analysis by atom probe tomography (APT) due to issues with specimen preparation, field evaporation and data reconstruction. The feasibility of encapsulating such non-compact matter in a matrix to enable APT measurements is investigated using nanoparticles as an example. Simulations of field evaporation of a void, and the resulting artifacts in ion trajectory, underpin the requirement that no voids remain after encapsulation. The approach is demonstrated by encapsulating Pt nanoparticles in an ZnO:Al matrix created by atomic layer deposition, a growth technique which offers very high surface coverage and conformality. APT measurements of the Pt nanoparticles are correlated with transmission electron microscopy images and numerical simulations in order to evaluate the accuracy of the APT reconstruction. - Highlights: • Pt nanoparticles were analyzed using atom probe tomography and TEM. • The particles were prepared by encapsulation using atomic layer deposition. • Simulation of field evaporation near a void results in aberrations in ion trajectories. • Apparent differences between TEM and APT analyses are reconciled through simulation of field evaporation from a low-field matrix containing high-field NPs; ion trajectory aberrations are shown to lead to an apparent mixing of the matrix into the NPs.

  6. Incremental Volumetric Remapping Method: Analysis and Error Evaluation

    International Nuclear Information System (INIS)

    Baptista, A. J.; Oliveira, M. C.; Rodrigues, D. M.; Menezes, L. F.; Alves, J. L.

    2007-01-01

    In this paper the error associated with the remapping problem is analyzed. A range of numerical results that assess the performance of three different remapping strategies, applied to FE meshes that typically are used in sheet metal forming simulation, are evaluated. One of the selected strategies is the previously presented Incremental Volumetric Remapping method (IVR), which was implemented in the in-house code DD3TRIM. The IVR method fundaments consists on the premise that state variables in all points associated to a Gauss volume of a given element are equal to the state variable quantities placed in the correspondent Gauss point. Hence, given a typical remapping procedure between a donor and a target mesh, the variables to be associated to a target Gauss volume (and point) are determined by a weighted average. The weight function is the Gauss volume percentage of each donor element that is located inside the target Gauss volume. The calculus of the intersecting volumes between the donor and target Gauss volumes is attained incrementally, for each target Gauss volume, by means of a discrete approach. The other two remapping strategies selected are based in the interpolation/extrapolation of variables by using the finite element shape functions or moving least square interpolants. The performance of the three different remapping strategies is address with two tests. The first remapping test was taken from a literature work. The test consists in remapping successively a rotating symmetrical mesh, throughout N increments, in an angular span of 90 deg. The second remapping error evaluation test consists of remapping an irregular element shape target mesh from a given regular element shape donor mesh and proceed with the inverse operation. In this second test the computation effort is also measured. The results showed that the error level associated to IVR can be very low and with a stable evolution along the number of remapping procedures when compared with the

  7. ANALYSIS AND CORRECTION OF SYSTEMATIC HEIGHT MODEL ERRORS

    Directory of Open Access Journals (Sweden)

    K. Jacobsen

    2016-06-01

    Full Text Available The geometry of digital height models (DHM determined with optical satellite stereo combinations depends upon the image orientation, influenced by the satellite camera, the system calibration and attitude registration. As standard these days the image orientation is available in form of rational polynomial coefficients (RPC. Usually a bias correction of the RPC based on ground control points is required. In most cases the bias correction requires affine transformation, sometimes only shifts, in image or object space. For some satellites and some cases, as caused by small base length, such an image orientation does not lead to the possible accuracy of height models. As reported e.g. by Yong-hua et al. 2015 and Zhang et al. 2015, especially the Chinese stereo satellite ZiYuan-3 (ZY-3 has a limited calibration accuracy and just an attitude recording of 4 Hz which may not be satisfying. Zhang et al. 2015 tried to improve the attitude based on the color sensor bands of ZY-3, but the color images are not always available as also detailed satellite orientation information. There is a tendency of systematic deformation at a Pléiades tri-stereo combination with small base length. The small base length enlarges small systematic errors to object space. But also in some other satellite stereo combinations systematic height model errors have been detected. The largest influence is the not satisfying leveling of height models, but also low frequency height deformations can be seen. A tilt of the DHM by theory can be eliminated by ground control points (GCP, but often the GCP accuracy and distribution is not optimal, not allowing a correct leveling of the height model. In addition a model deformation at GCP locations may lead to not optimal DHM leveling. Supported by reference height models better accuracy has been reached. As reference height model the Shuttle Radar Topography Mission (SRTM digital surface model (DSM or the new AW3D30 DSM, based on ALOS

  8. Bayesian soft x-ray tomography and MHD mode analysis on HL-2A

    Science.gov (United States)

    Li, Dong; Liu, Yi; Svensson, J.; Liu, Y. Q.; Song, X. M.; Yu, L. M.; Mao, Rui; Fu, B. Z.; Deng, Wei; Yuan, B. S.; Ji, X. Q.; Xu, Yuan; Chen, Wei; Zhou, Yan; Yang, Q. W.; Duan, X. R.; Liu, Yong; HL-2A Team

    2016-03-01

    A Bayesian based tomography method using so-called Gaussian processes (GPs) for the emission model has been applied to the soft x-ray (SXR) diagnostics on HL-2A tokamak. To improve the accuracy of reconstructions, the standard GP is extended to a non-stationary version so that different smoothness between the plasma center and the edge can be taken into account in the algorithm. The uncertainty in the reconstruction arising from measurement errors and incapability can be fully analyzed by the usage of Bayesian probability theory. In this work, the SXR reconstructions by this non-stationary Gaussian processes tomography (NSGPT) method have been compared with the equilibrium magnetic flux surfaces, generally achieving a satisfactory agreement in terms of both shape and position. In addition, singular-value-decomposition (SVD) and Fast Fourier Transform (FFT) techniques have been applied for the analysis of SXR and magnetic diagnostics, in order to explore the spatial and temporal features of the saturated long-lived magnetohydrodynamics (MHD) instability induced by energetic particles during neutral beam injection (NBI) on HL-2A. The result shows that this ideal internal kink instability has a dominant m/n  =  1/1 mode structure along with a harmonics m/n  =  2/2, which are coupled near the q  =  1 surface with a rotation frequency of 12 kHz.

  9. Stochastic and sensitivity analysis of shape error of inflatable antenna reflectors

    Science.gov (United States)

    San, Bingbing; Yang, Qingshan; Yin, Liwei

    2017-03-01

    Inflatable antennas are promising candidates to realize future satellite communications and space observations since they are lightweight, low-cost and small-packaged-volume. However, due to their high flexibility, inflatable reflectors are difficult to manufacture accurately, which may result in undesirable shape errors, and thus affect their performance negatively. In this paper, the stochastic characteristics of shape errors induced during manufacturing process are investigated using Latin hypercube sampling coupled with manufacture simulations. Four main random error sources are involved, including errors in membrane thickness, errors in elastic modulus of membrane, boundary deviations and pressure variations. Using regression and correlation analysis, a global sensitivity study is conducted to rank the importance of these error sources. This global sensitivity analysis is novel in that it can take into account the random variation and the interaction between error sources. Analyses are parametrically carried out with various focal-length-to-diameter ratios (F/D) and aperture sizes (D) of reflectors to investigate their effects on significance ranking of error sources. The research reveals that RMS (Root Mean Square) of shape error is a random quantity with an exponent probability distribution and features great dispersion; with the increase of F/D and D, both mean value and standard deviation of shape errors are increased; in the proposed range, the significance ranking of error sources is independent of F/D and D; boundary deviation imposes the greatest effect with a much higher weight than the others; pressure variation ranks the second; error in thickness and elastic modulus of membrane ranks the last with very close sensitivities to pressure variation. Finally, suggestions are given for the control of the shape accuracy of reflectors and allowable values of error sources are proposed from the perspective of reliability.

  10. Contribution of Error Analysis to Foreign Language Teaching

    Directory of Open Access Journals (Sweden)

    Vacide ERDOĞAN

    2014-01-01

    Full Text Available It is inevitable that learners make mistakes in the process of foreign language learning.However, what is questioned by language teachers is why students go on making the same mistakeseven when such mistakes have been repeatedly pointed out to them. Yet not all mistakes are the same;sometimes they seem to be deeply ingrained, but at other times students correct themselves with ease.Thus, researchers and teachers of foreign language came to realize that the mistakes a person made inthe process of constructing a new system of language is needed to be analyzed carefully, for theypossibly held in them some of the keys to the understanding of second language acquisition. In thisrespect, the aim of this study is to point out the significance of learners’ errors for they provideevidence of how language is learned and what strategies or procedures the learners are employing inthe discovery of language.

  11. Study on analysis from sources of error for Airborne LIDAR

    Science.gov (United States)

    Ren, H. C.; Yan, Q.; Liu, Z. J.; Zuo, Z. Q.; Xu, Q. Q.; Li, F. F.; Song, C.

    2016-11-01

    With the advancement of Aerial Photogrammetry, it appears that to obtain geo-spatial information of high spatial and temporal resolution provides a new technical means for Airborne LIDAR measurement techniques, with unique advantages and broad application prospects. Airborne LIDAR is increasingly becoming a new kind of space for earth observation technology, which is mounted by launching platform for aviation, accepting laser pulses to get high-precision, high-density three-dimensional coordinate point cloud data and intensity information. In this paper, we briefly demonstrates Airborne laser radar systems, and that some errors about Airborne LIDAR data sources are analyzed in detail, so the corresponding methods is put forwarded to avoid or eliminate it. Taking into account the practical application of engineering, some recommendations were developed for these designs, which has crucial theoretical and practical significance in Airborne LIDAR data processing fields.

  12. Hebbian errors in learning: an analysis using the Oja model.

    Science.gov (United States)

    Rădulescu, Anca; Cox, Kingsley; Adams, Paul

    2009-06-21

    Recent work on long term potentiation in brain slices shows that Hebb's rule is not completely synapse-specific, probably due to intersynapse diffusion of calcium or other factors. We previously suggested that such errors in Hebbian learning might be analogous to mutations in evolution. We examine this proposal quantitatively, extending the classical Oja unsupervised model of learning by a single linear neuron to include Hebbian inspecificity. We introduce an error matrix E, which expresses possible crosstalk between updating at different connections. When there is no inspecificity, this gives the classical result of convergence to the first principal component of the input distribution (PC1). We show the modified algorithm converges to the leading eigenvector of the matrix EC, where C is the input covariance matrix. In the most biologically plausible case when there are no intrinsically privileged connections, E has diagonal elements Q and off-diagonal elements (1-Q)/(n-1), where Q, the quality, is expected to decrease with the number of inputs n and with a synaptic parameter b that reflects synapse density, calcium diffusion, etc. We study the dependence of the learning accuracy on b, n and the amount of input activity or correlation (analytically and computationally). We find that accuracy increases (learning becomes gradually less useful) with increases in b, particularly for intermediate (i.e., biologically realistic) correlation strength, although some useful learning always occurs up to the trivial limit Q=1/n. We discuss the relation of our results to Hebbian unsupervised learning in the brain. When the mechanism lacks specificity, the network fails to learn the expected, and typically most useful, result, especially when the input correlation is weak. Hebbian crosstalk would reflect the very high density of synapses along dendrites, and inevitably degrades learning.

  13. The study of error for analysis in dynamic image from the error of count rates in Nal (Tl) scintillation camera

    International Nuclear Information System (INIS)

    Oh, Joo Young; Kang, Chun Goo; Kim, Jung Yul; Oh, Ki Baek; Kim, Jae Sam; Park, Hoon Hee

    2013-01-01

    This study is aimed to evaluate the effect of T 1/2 upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with '9 9m TcO 4 - of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in χ 2 test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of T 1/2 error from change of gradient with -0.25% to +0.25%, if T 1/2 is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see T 1/2 error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a

  14. Analysis of measured data of human body based on error correcting frequency

    Science.gov (United States)

    Jin, Aiyan; Peipei, Gao; Shang, Xiaomei

    2014-04-01

    Anthropometry is to measure all parts of human body surface, and the measured data is the basis of analysis and study of the human body, establishment and modification of garment size and formulation and implementation of online clothing store. In this paper, several groups of the measured data are gained, and analysis of data error is gotten by analyzing the error frequency and using analysis of variance method in mathematical statistics method. Determination of the measured data accuracy and the difficulty of measured parts of human body, further studies of the causes of data errors, and summarization of the key points to minimize errors possibly are also mentioned in the paper. This paper analyses the measured data based on error frequency, and in a way , it provides certain reference elements to promote the garment industry development.

  15. Boundary error analysis and categorization in the TRECVID news story segmentation task

    NARCIS (Netherlands)

    Arlandis, J.; Over, P.; Kraaij, W.

    2005-01-01

    In this paper, an error analysis based on boundary error popularity (frequency) including semantic boundary categorization is applied in the context of the news story segmentation task from TRECVTD1. Clusters of systems were defined based on the input resources they used including video, audio and

  16. An Analysis of College Students' Attitudes towards Error Correction in EFL Context

    Science.gov (United States)

    Zhu, Honglin

    2010-01-01

    This article is based on a survey on the attitudes towards the error correction by their teachers in the process of teaching and learning and it is intended to improve the language teachers' understanding of the nature of error correction. Based on the analysis, the article expounds some principles and techniques that can be applied in the process…

  17. Analysis of Errors and Misconceptions in the Learning of Calculus by Undergraduate Students

    Science.gov (United States)

    Muzangwa, Jonatan; Chifamba, Peter

    2012-01-01

    This paper is going to analyse errors and misconceptions in an undergraduate course in Calculus. The study will be based on a group of 10 BEd. Mathematics students at Great Zimbabwe University. Data is gathered through use of two exercises on Calculus 1&2.The analysis of the results from the tests showed that a majority of the errors were due…

  18. The treatment of commission errors in first generation human reliability analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Alvarengga, Marco Antonio Bayout; Fonseca, Renato Alves da, E-mail: bayout@cnen.gov.b, E-mail: rfonseca@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN) Rio de Janeiro, RJ (Brazil); Melo, Paulo Fernando Frutuoso e, E-mail: frutuoso@nuclear.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear

    2011-07-01

    Human errors in human reliability analysis can be classified generically as errors of omission and commission errors. Omission errors are related to the omission of any human action that should have been performed, but does not occur. Errors of commission are those related to human actions that should not be performed, but which in fact are performed. Both involve specific types of cognitive error mechanisms, however, errors of commission are more difficult to model because they are characterized by non-anticipated actions that are performed instead of others that are omitted (omission errors) or are entered into an operational task without being part of the normal sequence of this task. The identification of actions that are not supposed to occur depends on the operational context that will influence or become easy certain unsafe actions of the operator depending on the operational performance of its parameters and variables. The survey of operational contexts and associated unsafe actions is a characteristic of second-generation models, unlike the first generation models. This paper discusses how first generation models can treat errors of commission in the steps of detection, diagnosis, decision-making and implementation, in the human information processing, particularly with the use of THERP tables of errors quantification. (author)

  19. An Analysis of Students Error In Solving PISA 2012 And Its Scaffolding

    Directory of Open Access Journals (Sweden)

    Yurizka Melia Sari

    2017-08-01

    Full Text Available Based on PISA survey in 2012, Indonesia was only placed on 64 out of 65 participating countries. The survey suggest that the students’ ability of reasoning, spatial orientation, and problem solving are lower compare with other participants countries, especially in Shouth East Asia. Nevertheless, the result of PISA does not elicit clearly on the students’ inability in solving PISA problem such as the location and the types of student’s errors. Therefore, analyzing students’ error in solving PISA problem would be essential countermeasure to help the students in solving mathematics problems and to develop scaffolding. Based on the data analysis, it is found that there are 5 types of error which is made by the subject. They consist of reading error, comprehension error, transformation error, process skill error, and encoding error. The most common mistake that subject do is encoding error with a percentage of 26%. While reading is the fewest errors made by the subjects that is only 12%. The types of given scaffolding was explaining the problem carefully and making a summary of new words and find the meaning of them, restructuring problem-solving strategies and reviewing the results of the completion of the problem.

  20. Two-component model application for error calculus in the environmental monitoring data analysis

    International Nuclear Information System (INIS)

    Carvalho, Maria Angelica G.; Hiromoto, Goro

    2002-01-01

    Analysis and interpretation of results of an environmental monitoring program is often based on the evaluation of the mean value of a particular set of data, which is strongly affected by the analytical errors associated with each measurement. A model proposed by Rocke and Lorenzato assumes two error components, one additive and one multiplicative, to deal with lower and higher concentration values in a single model. In this communication, an application of this method for re-evaluation of the errors reported in a large set of results of total alpha measurements in a environmental sample is presented. The results show that the mean values calculated taking into account the new errors is higher than as obtained with the original errors, being an indicative that the analytical errors reported before were underestimated in the region of lower concentrations. (author)

  1. Analysis of 3D crack propagation by microfocus computed tomography

    International Nuclear Information System (INIS)

    Ao Bo; Chen Fuxing; Deng Cuizhen; Zeng Yabin

    2014-01-01

    The three-point bending test of notched specimens of 2A50 forging aluminum was performed by high frequency fatigue tester, and the surface cracks of different stages were analyzed and contrasted by SEM. The crack was reconstructed by microfocus computed tomography, and its size, position and distribution were visually displayed through 3D visualization. The crack propagation behaviors were researched through gray value and position of crack front of 2D CT images in two adjacent stages, and the results show that crack propagation is irregular. The projection image of crack was obtained if crack of two stages projected onto the reference plane respectively, a significant increase of new crack propagation was observed compared with the previous projection of crack, and the distribution curve of crack front of two stages was displayed. The 3D increment distribution of the crack front propagation was obtained through the 3D crack analysis of two stages. (authors)

  2. Analysis technique for controlling system wavefront error with active/adaptive optics

    Science.gov (United States)

    Genberg, Victor L.; Michels, Gregory J.

    2017-08-01

    The ultimate goal of an active mirror system is to control system level wavefront error (WFE). In the past, the use of this technique was limited by the difficulty of obtaining a linear optics model. In this paper, an automated method for controlling system level WFE using a linear optics model is presented. An error estimate is included in the analysis output for both surface error disturbance fitting and actuator influence function fitting. To control adaptive optics, the technique has been extended to write system WFE in state space matrix form. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

  3. Detection method of nonlinearity errors by statistical signal analysis in heterodyne Michelson interferometer.

    Science.gov (United States)

    Hu, Juju; Hu, Haijiang; Ji, Yinghua

    2010-03-15

    Periodic nonlinearity that ranges from tens of nanometers to a few nanometers in heterodyne interferometer limits its use in high accuracy measurement. A novel method is studied to detect the nonlinearity errors based on the electrical subdivision and the analysis method of statistical signal in heterodyne Michelson interferometer. Under the movement of micropositioning platform with the uniform velocity, the method can detect the nonlinearity errors by using the regression analysis and Jackknife estimation. Based on the analysis of the simulations, the method can estimate the influence of nonlinearity errors and other noises for the dimensions measurement in heterodyne Michelson interferometer.

  4. Optimization of sample absorbance for quantitative analysis in the presence of pathlength error in the IR and NIR regions

    International Nuclear Information System (INIS)

    Hirschfeld, T.; Honigs, D.; Hieftje, G.

    1985-01-01

    Optical absorbance levels for quantiative analysis in the presence of photometric error have been described in the past. In newer instrumentation, such as FT-IR and NIRA spectrometers, the photometric error is no longer limiting. In these instruments, pathlength error due to cell or sampling irreproducibility is often a major concern. One can derive optimal absorbance by taking both pathlength and photometric errors into account. This paper analyzes the cases of pathlength error >> photometric error (trivial) and various cases in which the pathlength errors and the photometric error are of the same order: adjustable concentration (trivial until dilution errors are considered), constant relative pathlength error (trivial), and constant absolute pathlength error. The latter, in particular, is analyzed in detail to give the behavior of the error, the behavior of the optimal absorbance in its presence, and the total error levels attainable

  5. Knowledge-base for the new human reliability analysis method, A Technique for Human Error Analysis (ATHEANA)

    International Nuclear Information System (INIS)

    Cooper, S.E.; Wreathall, J.; Thompson, C.M., Drouin, M.; Bley, D.C.

    1996-01-01

    This paper describes the knowledge base for the application of the new human reliability analysis (HRA) method, a ''A Technique for Human Error Analysis'' (ATHEANA). Since application of ATHEANA requires the identification of previously unmodeled human failure events, especially errors of commission, and associated error-forcing contexts (i.e., combinations of plant conditions and performance shaping factors), this knowledge base is an essential aid for the HRA analyst

  6. Accounting for covariate measurement error in a Cox model analysis of recurrence of depression.

    Science.gov (United States)

    Liu, K; Mazumdar, S; Stone, R A; Dew, M A; Houck, P R; Reynolds, C F

    2001-01-01

    When a covariate measured with error is used as a predictor in a survival analysis using the Cox model, the parameter estimate is usually biased. In clinical research, covariates measured without error such as treatment procedure or sex are often used in conjunction with a covariate measured with error. In a randomized clinical trial of two types of treatments, we account for the measurement error in the covariate, log-transformed total rapid eye movement (REM) activity counts, in a Cox model analysis of the time to recurrence of major depression in an elderly population. Regression calibration and two variants of a likelihood-based approach are used to account for measurement error. The likelihood-based approach is extended to account for the correlation between replicate measures of the covariate. Using the replicate data decreases the standard error of the parameter estimate for log(total REM) counts while maintaining the bias reduction of the estimate. We conclude that covariate measurement error and the correlation between replicates can affect results in a Cox model analysis and should be accounted for. In the depression data, these methods render comparable results that have less bias than the results when measurement error is ignored.

  7. An error analysis in the early grades mathematics – a learning opportunity?

    Directory of Open Access Journals (Sweden)

    Roelien Herholdt

    2014-07-01

    Full Text Available Error analysis is the study of errors in learners’ work with a view to looking for possible explanations for these errors. It is a multifaceted activity involving analysis of correct, partially correct and incorrect processes and thinking about possible remediating strategies. This paper reports on such an analysis of learner tests. The tests were administered as part of the evaluation of an intervention project that aimed to teach mathematical problem solving skills to grade 1-4 learners. Quantitative error analysis was carried out using a coding sheet for each grade. A reliability coefficient was found for each test, as were item means and discrimination indexes for each item. The analysis provided some insight into the more common procedural and conceptual errors evidenced in the learners’ scripts. Findings showed similar difficulties across intervention and control schools and highlighted particular areas of difficulty. The authors argue that this analysis is an example of large-scale error analysis, but that the analysis method could be adopted by teachers of grades 1-4.

  8. Research on Human-Error Factors of Civil Aircraft Pilots Based On Grey Relational Analysis

    Directory of Open Access Journals (Sweden)

    Guo Yundong

    2018-01-01

    Full Text Available In consideration of the situation that civil aviation accidents involve many human-error factors and show the features of typical grey systems, an index system of civil aviation accident human-error factors is built using human factor analysis and classification system model. With the data of accidents happened worldwide between 2008 and 2011, the correlation between human-error factors can be analyzed quantitatively using the method of grey relational analysis. Research results show that the order of main factors affecting pilot human-error factors is preconditions for unsafe acts, unsafe supervision, organization and unsafe acts. The factor related most closely with second-level indexes and pilot human-error factors is the physical/mental limitations of pilots, followed by supervisory violations. The relevancy between the first-level indexes and the corresponding second-level indexes and the relevancy between second-level indexes can also be analyzed quantitatively.

  9. Quality of IT service delivery — Analysis and framework for human error prevention

    KAUST Repository

    Shwartz, L.

    2010-12-01

    In this paper, we address the problem of reducing the occurrence of Human Errors that cause service interruptions in IT Service Support and Delivery operations. Analysis of a large volume of service interruption records revealed that more than 21% of interruptions were caused by human error. We focus on Change Management, the process with the largest risk of human error, and identify the main instances of human errors as the 4 Wrongs: request, time, configuration item, and command. Analysis of change records revealed that the humanerror prevention by partial automation is highly relevant. We propose the HEP Framework, a framework for execution of IT Service Delivery operations that reduces human error by addressing the 4 Wrongs using content integration, contextualization of operation patterns, partial automation of command execution, and controlled access to resources.

  10. A GENERAL STUDY OF THE INFLUENCE OF CATASTROPHIC PHOTOMETRIC REDSHIFT ERRORS ON COSMOLOGY WITH COSMIC SHEAR TOMOGRAPHY

    International Nuclear Information System (INIS)

    Hearin, Andrew P.; Zentner, Andrew R.; Ma Zhaoming; Huterer, Dragan

    2010-01-01

    A goal of forthcoming imaging surveys is to use weak gravitational lensing shear measurements to constrain dark energy. A challenge to this program is that redshifts to the lensed, source galaxies must be determined using photometric, rather than spectroscopic, information. We quantify the importance of uncalibrated photometric redshift outliers to the dark energy goals of forthcoming imaging surveys in a manner that does not assume any particular photometric redshift technique or template. In so doing, we provide an approximate blueprint for computing the influence of specific outlier populations on dark energy constraints. We find that outlier populations whose photo-z distributions are tightly localized about a significantly biased redshift must be controlled to a per-galaxy rate of (1-3) x 10 -3 to insure that systematic errors on dark energy parameters are rendered negligible. In the complementary limit, a subset of imaged galaxies with uncalibrated photometric redshifts distributed over a broad range must be limited to fewer than a per-galaxy error rate of F cat ∼ -4 . Additionally, we explore the relative importance of calibrating the photo-z's of a core set of relatively well-understood galaxies as compared to the need to identify potential catastrophic photo-z outliers. We discuss the degradation of the statistical constraints on dark energy parameters induced by excising source galaxies at high- and low-photometric redshifts, concluding that removing galaxies with photometric redshifts z ph ∼> 2.4 and z ph ∼< 0.3 may mitigate damaging catastrophic redshift outliers at a relatively small (∼<20%) cost in statistical error. In an Appendix, we show that forecasts for the degradation in dark energy parameter constraints due to uncertain photometric redshifts depend sensitively on the treatment of the nonlinear matter power spectrum. In particular, previous work using Peacock and Dodds may have overestimated the photo-z calibration requirements of

  11. Error sensitivity analysis in 10-30-day extended range forecasting by using a nonlinear cross-prediction error model

    Science.gov (United States)

    Xia, Zhiye; Xu, Lisheng; Chen, Hongbin; Wang, Yongqian; Liu, Jinbao; Feng, Wenlan

    2017-06-01

    Extended range forecasting of 10-30 days, which lies between medium-term and climate prediction in terms of timescale, plays a significant role in decision-making processes for the prevention and mitigation of disastrous meteorological events. The sensitivity of initial error, model parameter error, and random error in a nonlinear crossprediction error (NCPE) model, and their stability in the prediction validity period in 10-30-day extended range forecasting, are analyzed quantitatively. The associated sensitivity of precipitable water, temperature, and geopotential height during cases of heavy rain and hurricane is also discussed. The results are summarized as follows. First, the initial error and random error interact. When the ratio of random error to initial error is small (10-6-10-2), minor variation in random error cannot significantly change the dynamic features of a chaotic system, and therefore random error has minimal effect on the prediction. When the ratio is in the range of 10-1-2 (i.e., random error dominates), attention should be paid to the random error instead of only the initial error. When the ratio is around 10-2-10-1, both influences must be considered. Their mutual effects may bring considerable uncertainty to extended range forecasting, and de-noising is therefore necessary. Second, in terms of model parameter error, the embedding dimension m should be determined by the factual nonlinear time series. The dynamic features of a chaotic system cannot be depicted because of the incomplete structure of the attractor when m is small. When m is large, prediction indicators can vanish because of the scarcity of phase points in phase space. A method for overcoming the cut-off effect ( m > 4) is proposed. Third, for heavy rains, precipitable water is more sensitive to the prediction validity period than temperature or geopotential height; however, for hurricanes, geopotential height is most sensitive, followed by precipitable water.

  12. Error and Uncertainty Analysis for Ecological Modeling and Simulation

    Science.gov (United States)

    2001-12-01

    nitrate flux to the Gulf of Mexico. Nature (Brief Communication) 414: 166-167. (Uncertainty analysis done with SERDP software) Gertner, G., G...D. Goolsby 2001. Relating N inputs to the Mississippi River Basin and nitrate flux in the Lower Mississippi River: A comparison of approaches...Journal of Remote Sensing, 25(4):367-380. Wu, J., D.E. Jelinski, M. Luck, and P.T. Tueller, 2000. Multiscale analysis of landscape heterogeneity: scale

  13. Iterative reconstruction for quantitative computed tomography analysis of emphysema: consistent results using different tube currents

    Directory of Open Access Journals (Sweden)

    Yamashiro T

    2015-02-01

    Full Text Available Tsuneo Yamashiro,1 Tetsuhiro Miyara,1 Osamu Honda,2 Noriyuki Tomiyama,2 Yoshiharu Ohno,3 Satoshi Noma,4 Sadayuki Murayama1 On behalf of the ACTIve Study Group 1Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan; 2Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 4Department of Radiology, Tenri Hospital, Tenri, Nara, Japan Purpose: To assess the advantages of iterative reconstruction for quantitative computed tomography (CT analysis of pulmonary emphysema. Materials and methods: Twenty-two patients with pulmonary emphysema underwent chest CT imaging using identical scanners with three different tube currents: 240, 120, and 60 mA. Scan data were converted to CT images using Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D and a conventional filtered-back projection mode. Thus, six scans with and without AIDR3D were generated per patient. All other scanning and reconstruction settings were fixed. The percent low attenuation area (LAA%; < -950 Hounsfield units and the lung density 15th percentile were automatically measured using a commercial workstation. Comparisons of LAA% and 15th percentile results between scans with and without using AIDR3D were made by Wilcoxon signed-rank tests. Associations between body weight and measurement errors among these scans were evaluated by Spearman rank correlation analysis. Results: Overall, scan series without AIDR3D had higher LAA% and lower 15th percentile values than those with AIDR3D at each tube current (P<0.0001. For scan series without AIDR3D, lower tube currents resulted in higher LAA% values and lower 15th percentiles. The extent of emphysema was significantly different between each pair among scans when not using AIDR3D (LAA%, P<0.0001; 15th percentile, P<0.01, but was not

  14. Mixed Methods Analysis of Medical Error Event Reports: A Report from the ASIPS Collaborative

    National Research Council Canada - National Science Library

    Harris, Daniel M; Westfall, John M; Fernald, Douglas H; Duclos, Christine W; West, David R; Niebauer, Linda; Marr, Linda; Quintela, Javan; Main, Deborah S

    2005-01-01

    .... This paper presents a mixed methods approach to analyzing narrative error event reports. Mixed methods studies integrate one or more qualitative and quantitative techniques for data collection and analysis...

  15. Quality of IT service delivery — Analysis and framework for human error prevention

    KAUST Repository

    Shwartz, L.; Rosu, D.; Loewenstern, D.; Buco, M. J.; Guo, S.; Lavrado, Rafael Coelho; Gupta, M.; De, P.; Madduri, V.; Singh, J. K.

    2010-01-01

    In this paper, we address the problem of reducing the occurrence of Human Errors that cause service interruptions in IT Service Support and Delivery operations. Analysis of a large volume of service interruption records revealed that more than 21

  16. Ergodic Capacity Analysis of Free-Space Optical Links with Nonzero Boresight Pointing Errors

    KAUST Repository

    Ansari, Imran Shafique; Alouini, Mohamed-Slim; Cheng, Julian

    2015-01-01

    A unified capacity analysis of a free-space optical (FSO) link that accounts for nonzero boresight pointing errors and both types of detection techniques (i.e. intensity modulation/ direct detection as well as heterodyne detection) is addressed

  17. Diffraction analysis of sidelobe characteristics of optical elements with ripple error

    Science.gov (United States)

    Zhao, Lei; Luo, Yupeng; Bai, Jian; Zhou, Xiangdong; Du, Juan; Liu, Qun; Luo, Yujie

    2018-03-01

    The ripple errors of the lens lead to optical damage in high energy laser system. The analysis of sidelobe on the focal plane, caused by ripple error, provides a reference to evaluate the error and the imaging quality. In this paper, we analyze the diffraction characteristics of sidelobe of optical elements with ripple errors. First, we analyze the characteristics of ripple error and build relationship between ripple error and sidelobe. The sidelobe results from the diffraction of ripple errors. The ripple error tends to be periodic due to fabrication method on the optical surface. The simulated experiments are carried out based on angular spectrum method by characterizing ripple error as rotationally symmetric periodic structures. The influence of two major parameter of ripple including spatial frequency and peak-to-valley value to sidelobe is discussed. The results indicate that spatial frequency and peak-to-valley value both impact sidelobe at the image plane. The peak-tovalley value is the major factor to affect the energy proportion of the sidelobe. The spatial frequency is the major factor to affect the distribution of the sidelobe at the image plane.

  18. Analysis of Employee's Survey for Preventing Human-Errors

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Chanho; Kim, Younggab; Joung, Sanghoun [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Human errors in nuclear power plant can cause large and small events or incidents. These events or incidents are one of main contributors of reactor trip and might threaten the safety of nuclear plants. To prevent human-errors, KHNP(nuclear power plants) introduced 'Human-error prevention techniques' and have applied the techniques to main parts such as plant operation, operation support, and maintenance and engineering. This paper proposes the methods to prevent and reduce human-errors in nuclear power plants through analyzing survey results which includes the utilization of the human-error prevention techniques and the employees' awareness of preventing human-errors. With regard to human-error prevention, this survey analysis presented the status of the human-error prevention techniques and the employees' awareness of preventing human-errors. Employees' understanding and utilization of the techniques was generally high and training level of employee and training effect on actual works were in good condition. Also, employees answered that the root causes of human-error were due to working environment including tight process, manpower shortage, and excessive mission rather than personal negligence or lack of personal knowledge. Consideration of working environment is certainly needed. At the present time, based on analyzing this survey, the best methods of preventing human-error are personal equipment, training/education substantiality, private mental health check before starting work, prohibit of multiple task performing, compliance with procedures, and enhancement of job site review. However, the most important and basic things for preventing human-error are interests of workers and organizational atmosphere such as communication between managers and workers, and communication between employees and bosses.

  19. Spectroscopic Doppler analysis for visible-light optical coherence tomography

    Science.gov (United States)

    Shu, Xiao; Liu, Wenzhong; Duan, Lian; Zhang, Hao F.

    2017-12-01

    Retinal oxygen metabolic rate can be effectively measured by visible-light optical coherence tomography (vis-OCT), which simultaneously quantifies oxygen saturation and blood flow rate in retinal vessels through spectroscopic analysis and Doppler measurement, respectively. Doppler OCT relates phase variation between sequential A-lines to the axial flow velocity of the scattering medium. The detectable phase shift is between -π and π due to its periodicity, which limits the maximum measurable unambiguous velocity without phase unwrapping. Using shorter wavelengths, vis-OCT is more vulnerable to phase ambiguity since flow induced phase variation is linearly related to the center wavenumber of the probing light. We eliminated the need for phase unwrapping using spectroscopic Doppler analysis. We split the whole vis-OCT spectrum into a series of narrow subbands and reconstructed vis-OCT images to extract corresponding Doppler phase shifts in all the subbands. Then, we quantified flow velocity by analyzing subband-dependent phase shift using linear regression. In the phantom experiment, we showed that spectroscopic Doppler analysis extended the measurable absolute phase shift range without conducting phase unwrapping. We also tested this method to quantify retinal blood flow in rodents in vivo.

  20. A posteriori error analysis of multiscale operator decomposition methods for multiphysics models

    International Nuclear Information System (INIS)

    Estep, D; Carey, V; Tavener, S; Ginting, V; Wildey, T

    2008-01-01

    Multiphysics, multiscale models present significant challenges in computing accurate solutions and for estimating the error in information computed from numerical solutions. In this paper, we describe recent advances in extending the techniques of a posteriori error analysis to multiscale operator decomposition solution methods. While the particulars of the analysis vary considerably with the problem, several key ideas underlie a general approach being developed to treat operator decomposition multiscale methods. We explain these ideas in the context of three specific examples

  1. Application of grey incidence analysis to connection between human errors and root cause

    International Nuclear Information System (INIS)

    Ren Yinxiang; Yu Ren; Zhou Gang; Chen Dengke

    2008-01-01

    By introducing grey incidence analysis, the relatively important impact of root cause upon human errors was researched in the paper. On the basis of WANO statistic data and grey incidence analysis, lack of alternate examine, bad basic operation, short of theoretical knowledge, relaxation of organization and management and deficiency of regulations are the important influence of root cause on human err ors. Finally, the question to reduce human errors was discussed. (authors)

  2. Solution-verified reliability analysis and design of bistable MEMS using error estimation and adaptivity.

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Michael Scott; Subia, Samuel Ramirez; Neckels, David; Hopkins, Matthew Morgan; Notz, Patrick K.; Adams, Brian M.; Carnes, Brian; Wittwer, Jonathan W.; Bichon, Barron J.; Copps, Kevin D.

    2006-10-01

    This report documents the results for an FY06 ASC Algorithms Level 2 milestone combining error estimation and adaptivity, uncertainty quantification, and probabilistic design capabilities applied to the analysis and design of bistable MEMS. Through the use of error estimation and adaptive mesh refinement, solution verification can be performed in an automated and parameter-adaptive manner. The resulting uncertainty analysis and probabilistic design studies are shown to be more accurate, efficient, reliable, and convenient.

  3. Kinematic Analysis of Speech Sound Sequencing Errors Induced by Delayed Auditory Feedback.

    Science.gov (United States)

    Cler, Gabriel J; Lee, Jackson C; Mittelman, Talia; Stepp, Cara E; Bohland, Jason W

    2017-06-22

    Delayed auditory feedback (DAF) causes speakers to become disfluent and make phonological errors. Methods for assessing the kinematics of speech errors are lacking, with most DAF studies relying on auditory perceptual analyses, which may be problematic, as errors judged to be categorical may actually represent blends of sounds or articulatory errors. Eight typical speakers produced nonsense syllable sequences under normal and DAF (200 ms). Lip and tongue kinematics were captured with electromagnetic articulography. Time-locked acoustic recordings were transcribed, and the kinematics of utterances with and without perceived errors were analyzed with existing and novel quantitative methods. New multivariate measures showed that for 5 participants, kinematic variability for productions perceived to be error free was significantly increased under delay; these results were validated by using the spatiotemporal index measure. Analysis of error trials revealed both typical productions of a nontarget syllable and productions with articulatory kinematics that incorporated aspects of both the target and the perceived utterance. This study is among the first to characterize articulatory changes under DAF and provides evidence for different classes of speech errors, which may not be perceptually salient. New methods were developed that may aid visualization and analysis of large kinematic data sets. https://doi.org/10.23641/asha.5103067.

  4. A New Error Analysis and Accuracy Synthesis Method for Shoe Last Machine

    Directory of Open Access Journals (Sweden)

    Bian Xiangjuan

    2014-05-01

    Full Text Available In order to improve the manufacturing precision of the shoe last machine, a new error-computing model has been put forward to. At first, Based on the special topological structure of the shoe last machine and multi-rigid body system theory, a spatial error-calculating model of the system was built; Then, the law of error distributing in the whole work space was discussed, and the maximum error position of the system was found; At last, The sensitivities of error parameters were analyzed at the maximum position and the accuracy synthesis was conducted by using Monte Carlo method. Considering the error sensitivities analysis, the accuracy of the main parts was distributed. Results show that the probability of the maximal volume error less than 0.05 mm of the new scheme was improved from 0.6592 to 0.7021 than the probability of the old scheme, the precision of the system was improved obviously, the model can be used for the error analysis and accuracy synthesis of the complex multi- embranchment motion chain system, and to improve the system precision of manufacturing.

  5. Decimal Fraction Arithmetic: Logical Error Analysis and Its Validation.

    Science.gov (United States)

    Standiford, Sally N.; And Others

    This report illustrates procedures of item construction for addition and subtraction examples involving decimal fractions. Using a procedural network of skills required to solve such examples, an item characteristic matrix of skills analysis was developed to describe the characteristics of the content domain by projected student difficulties. Then…

  6. Errors in instumental neutron activation analysis caused by matrix absorption

    International Nuclear Information System (INIS)

    Croudace, I.W.

    1979-01-01

    Instrumental neutron activation analysis of the geochemically important rare earth elements, together with Ta, Hf and U involves energies below 150 keV where absorption of radiation by the sample becomes inceasingly important. Determinations of the total mass absorption coefficients have been made. (C.F.)

  7. Non-destructive analysis and detection of internal characteristics of spruce logs through X computerized tomography

    International Nuclear Information System (INIS)

    Longuetaud, F.

    2005-10-01

    Computerized tomography allows a direct access to internal features of scanned logs on the basis of density and moisture content variations. The objective of this work is to assess the feasibility of an automatic detection of internal characteristics with the final aim of conducting scientific analyses. The database is constituted by CT images of 24 spruces obtained with a medical CT scanner. Studied trees are representative of several social status and are coming from four stands located in North-Eastern France, themselves are representative of several age, density and fertility classes. The automatic processing developed are the following. First, pith detection in logs dealing with the problem of knot presence and ring eccentricity. The accuracy of the localisation was less than one mm. Secondly, the detection of the sapwood/heart-wood limit in logs dealing with the problem of knot presence (main source of difficulty). The error on the diameter was 1.8 mm which corresponds to a relative error of 1.3 per cent. Thirdly, the detection of the whorls location and comparison with an optical method. Fourthly the detection of individualized knots. This process allows to count knots and to locate them in a log (longitudinal position and azimuth); however, the validation of the method and extraction of branch diameter and inclination are still to be developed. An application of this work was a variability analysis of the sapwood content in the trunk: at the within-tree level, the sapwood width was found to be constant under the living crown; at the between-tree level, a strong correlation was found with the amount of living branches. A great number of analyses are possible from our work results, among others: architectural analysis with the pith tracking and the apex death occurrence; analysis of radial variations of the heart-wood shape; analysis of the knot distribution in logs. (author)

  8. Dosimetric Effect of Intrafraction Motion and Residual Setup Error for Hypofractionated Prostate Intensity-Modulated Radiotherapy With Online Cone Beam Computed Tomography Image Guidance

    International Nuclear Information System (INIS)

    Adamson, Justus; Wu Qiuwen; Yan Di

    2011-01-01

    Purpose: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. Methods and Materials: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D 99 ). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D 99 reduction to 1%. Results: For 3-mm margins, D 99 reduction was ≤5% for 29/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by ∼47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D 99 could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were ≤2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. Conclusions: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.

  9. Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.

    LENUS (Irish Health Repository)

    Adamson, Justus

    2012-02-01

    PURPOSE: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D(99)). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D(99) reduction to 1%. RESULTS: For 3-mm margins, D(99) reduction was <\\/=5% for 29\\/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by ~47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D(99) could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were <\\/=2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. CONCLUSIONS: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.

  10. The recovery factors analysis of the human errors for research reactors

    International Nuclear Information System (INIS)

    Farcasiu, M.; Nitoi, M.; Apostol, M.; Turcu, I.; Florescu, Ghe.

    2006-01-01

    The results of many Probabilistic Safety Assessment (PSA) studies show a very significant contribution of human errors to systems unavailability of the nuclear installations. The treatment of human interactions is considered one of the major limitations in the context of PSA. To identify those human actions that can have an effect on system reliability or availability applying the Human Reliability Analysis (HRA) is necessary. The recovery factors analysis of the human action is an important step in HRA. This paper presents how can be reduced the human errors probabilities (HEP) using those elements that have the capacity to recovery human error. The recovery factors modeling is marked to identify error likelihood situations or situations that conduct at development of the accident. This analysis is realized by THERP method. The necessary information was obtained from the operating experience of the research reactor TRIGA of the INR Pitesti. The required data were obtained from generic databases. (authors)

  11. A theoretical basis for the analysis of multiversion software subject to coincident errors

    Science.gov (United States)

    Eckhardt, D. E., Jr.; Lee, L. D.

    1985-01-01

    Fundamental to the development of redundant software techniques (known as fault-tolerant software) is an understanding of the impact of multiple joint occurrences of errors, referred to here as coincident errors. A theoretical basis for the study of redundant software is developed which: (1) provides a probabilistic framework for empirically evaluating the effectiveness of a general multiversion strategy when component versions are subject to coincident errors, and (2) permits an analytical study of the effects of these errors. An intensity function, called the intensity of coincident errors, has a central role in this analysis. This function describes the propensity of programmers to introduce design faults in such a way that software components fail together when executing in the application environment. A condition under which a multiversion system is a better strategy than relying on a single version is given.

  12. Phonological analysis of substitution errors of patients with apraxia of speech

    Directory of Open Access Journals (Sweden)

    Maysa Luchesi Cera

    Full Text Available Abstract The literature on apraxia of speech describes the types and characteristics of phonological errors in this disorder. In general, phonemes affected by errors are described, but the distinctive features involved have not yet been investigated. Objective: To analyze the features involved in substitution errors produced by Brazilian-Portuguese speakers with apraxia of speech. Methods: 20 adults with apraxia of speech were assessed. Phonological analysis of the distinctive features involved in substitution type errors was carried out using the protocol for the evaluation of verbal and non-verbal apraxia. Results: The most affected features were: voiced, continuant, high, anterior, coronal, posterior. Moreover, the mean of the substitutions of marked to markedness features was statistically greater than the markedness to marked features. Conclusions: This study contributes toward a better characterization of the phonological errors found in apraxia of speech, thereby helping to diagnose communication disorders and the selection criteria of phonemes for rehabilitation in these patients.

  13. Covariance Analysis Tool (G-CAT) for Computing Ascent, Descent, and Landing Errors

    Science.gov (United States)

    Boussalis, Dhemetrios; Bayard, David S.

    2013-01-01

    G-CAT is a covariance analysis tool that enables fast and accurate computation of error ellipses for descent, landing, ascent, and rendezvous scenarios, and quantifies knowledge error contributions needed for error budgeting purposes. Because GCAT supports hardware/system trade studies in spacecraft and mission design, it is useful in both early and late mission/ proposal phases where Monte Carlo simulation capability is not mature, Monte Carlo simulation takes too long to run, and/or there is a need to perform multiple parametric system design trades that would require an unwieldy number of Monte Carlo runs. G-CAT is formulated as a variable-order square-root linearized Kalman filter (LKF), typically using over 120 filter states. An important property of G-CAT is that it is based on a 6-DOF (degrees of freedom) formulation that completely captures the combined effects of both attitude and translation errors on the propagated trajectories. This ensures its accuracy for guidance, navigation, and control (GN&C) analysis. G-CAT provides the desired fast turnaround analysis needed for error budgeting in support of mission concept formulations, design trade studies, and proposal development efforts. The main usefulness of a covariance analysis tool such as G-CAT is its ability to calculate the performance envelope directly from a single run. This is in sharp contrast to running thousands of simulations to obtain similar information using Monte Carlo methods. It does this by propagating the "statistics" of the overall design, rather than simulating individual trajectories. G-CAT supports applications to lunar, planetary, and small body missions. It characterizes onboard knowledge propagation errors associated with inertial measurement unit (IMU) errors (gyro and accelerometer), gravity errors/dispersions (spherical harmonics, masscons), and radar errors (multiple altimeter beams, multiple Doppler velocimeter beams). G-CAT is a standalone MATLAB- based tool intended to

  14. Disasters of endoscopic surgery and how to avoid them: error analysis.

    Science.gov (United States)

    Troidl, H

    1999-08-01

    For every innovation there are two sides to consider. For endoscopic surgery the positive side is more comfort for the patient, and the negative side is new complications, even disasters, such as injuries to organs (e.g., the bowel), vessels, and the common bile duct. These disasters are rare and seldom reported in the scientific world, as at conferences, at symposiums, and in publications. Today there are many methods for testing an innovation (controlled clinical trials, consensus conferences, audits, and confidential inquiries). Reporting "complications," however, does not help to avoid them. We need real methods for avoiding negative failures. The failure analysis is the method of choice in industry. If an airplane crashes, error analysis starts immediately. Humans make errors, and making errors means punishment. Failure analysis means rigorously and objectively investigating a clinical situation to find clinical relevant information for avoiding these negative events in the future. Error analysis has four important steps: (1) What was the clinical situation? (2) What has happened? (3) Most important: Why did it happen? (4) How do we avoid the negative event or disaster in the future. Error analysis has decisive advantages. It is easy to perform; it supplies clinically relevant information to help avoid it; and there is no need for money. It can be done everywhere; and the information is available in a short time. The other side of the coin is that error analysis is of course retrospective, it may not be objective, and most important it will probably have legal consequences. To be more effective in medicine and surgery we must handle our errors using a different approach. According to Sir Karl Popper: "The consituation is that we have to learn from our errors. To cover up failure is therefore the biggest intellectual sin.

  15. Use of error files in uncertainty analysis and data adjustment

    International Nuclear Information System (INIS)

    Chestnutt, M.M.; McCracken, A.K.; McCracken, A.K.

    1979-01-01

    Some results are given from uncertainty analyses on Pressurized Water Reactor (PWR) and Fast Reactor Theoretical Benchmarks. Upper limit estimates of calculated quantities are shown to be significantly reduced by the use of ENDF/B data covariance files and recently published few-group covariance matrices. Some problems in the analysis of single-material benchmark experiments are discussed with reference to the Winfrith iron benchmark experiment. Particular attention is given to the difficulty of making use of very extensive measurements which are likely to be a feature of this type of experiment. Preliminary results of an adjustment in iron are shown

  16. Minimizing treatment planning errors in proton therapy using failure mode and effects analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yuanshui, E-mail: yuanshui.zheng@okc.procure.com [ProCure Proton Therapy Center, 5901 W Memorial Road, Oklahoma City, Oklahoma 73142 and Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078-3072 (United States); Johnson, Randall; Larson, Gary [ProCure Proton Therapy Center, 5901 W Memorial Road, Oklahoma City, Oklahoma 73142 (United States)

    2016-06-15

    Purpose: Failure mode and effects analysis (FMEA) is a widely used tool to evaluate safety or reliability in conventional photon radiation therapy. However, reports about FMEA application in proton therapy are scarce. The purpose of this study is to apply FMEA in safety improvement of proton treatment planning at their center. Methods: The authors performed an FMEA analysis of their proton therapy treatment planning process using uniform scanning proton beams. The authors identified possible failure modes in various planning processes, including image fusion, contouring, beam arrangement, dose calculation, plan export, documents, billing, and so on. For each error, the authors estimated the frequency of occurrence, the likelihood of being undetected, and the severity of the error if it went undetected and calculated the risk priority number (RPN). The FMEA results were used to design their quality management program. In addition, the authors created a database to track the identified dosimetric errors. Periodically, the authors reevaluated the risk of errors by reviewing the internal error database and improved their quality assurance program as needed. Results: In total, the authors identified over 36 possible treatment planning related failure modes and estimated the associated occurrence, detectability, and severity to calculate the overall risk priority number. Based on the FMEA, the authors implemented various safety improvement procedures into their practice, such as education, peer review, and automatic check tools. The ongoing error tracking database provided realistic data on the frequency of occurrence with which to reevaluate the RPNs for various failure modes. Conclusions: The FMEA technique provides a systematic method for identifying and evaluating potential errors in proton treatment planning before they result in an error in patient dose delivery. The application of FMEA framework and the implementation of an ongoing error tracking system at their

  17. Minimizing treatment planning errors in proton therapy using failure mode and effects analysis

    International Nuclear Information System (INIS)

    Zheng, Yuanshui; Johnson, Randall; Larson, Gary

    2016-01-01

    Purpose: Failure mode and effects analysis (FMEA) is a widely used tool to evaluate safety or reliability in conventional photon radiation therapy. However, reports about FMEA application in proton therapy are scarce. The purpose of this study is to apply FMEA in safety improvement of proton treatment planning at their center. Methods: The authors performed an FMEA analysis of their proton therapy treatment planning process using uniform scanning proton beams. The authors identified possible failure modes in various planning processes, including image fusion, contouring, beam arrangement, dose calculation, plan export, documents, billing, and so on. For each error, the authors estimated the frequency of occurrence, the likelihood of being undetected, and the severity of the error if it went undetected and calculated the risk priority number (RPN). The FMEA results were used to design their quality management program. In addition, the authors created a database to track the identified dosimetric errors. Periodically, the authors reevaluated the risk of errors by reviewing the internal error database and improved their quality assurance program as needed. Results: In total, the authors identified over 36 possible treatment planning related failure modes and estimated the associated occurrence, detectability, and severity to calculate the overall risk priority number. Based on the FMEA, the authors implemented various safety improvement procedures into their practice, such as education, peer review, and automatic check tools. The ongoing error tracking database provided realistic data on the frequency of occurrence with which to reevaluate the RPNs for various failure modes. Conclusions: The FMEA technique provides a systematic method for identifying and evaluating potential errors in proton treatment planning before they result in an error in patient dose delivery. The application of FMEA framework and the implementation of an ongoing error tracking system at their

  18. Error analysis of marker-based object localization using a single-plane XRII

    International Nuclear Information System (INIS)

    Habets, Damiaan F.; Pollmann, Steven I.; Yuan, Xunhua; Peters, Terry M.; Holdsworth, David W.

    2009-01-01

    The role of imaging and image guidance is increasing in surgery and therapy, including treatment planning and follow-up. Fluoroscopy is used for two-dimensional (2D) guidance or localization; however, many procedures would benefit from three-dimensional (3D) guidance or localization. Three-dimensional computed tomography (CT) using a C-arm mounted x-ray image intensifier (XRII) can provide high-quality 3D images; however, patient dose and the required acquisition time restrict the number of 3D images that can be obtained. C-arm based 3D CT is therefore limited in applications for x-ray based image guidance or dynamic evaluations. 2D-3D model-based registration, using a single-plane 2D digital radiographic system, does allow for rapid 3D localization. It is our goal to investigate - over a clinically practical range - the impact of x-ray exposure on the resulting range of 3D localization precision. In this paper it is assumed that the tracked instrument incorporates a rigidly attached 3D object with a known configuration of markers. A 2D image is obtained by a digital fluoroscopic x-ray system and corrected for XRII distortions (±0.035 mm) and mechanical C-arm shift (±0.080 mm). A least-square projection-Procrustes analysis is then used to calculate the 3D position using the measured 2D marker locations. The effect of x-ray exposure on the precision of 2D marker localization and on 3D object localization was investigated using numerical simulations and x-ray experiments. The results show a nearly linear relationship between 2D marker localization precision and the 3D localization precision. However, a significant amplification of error, nonuniformly distributed among the three major axes, occurs, and that is demonstrated. To obtain a 3D localization error of less than ±1.0 mm for an object with 20 mm marker spacing, the 2D localization precision must be better than ±0.07 mm. This requirement was met for all investigated nominal x-ray exposures at 28 cm FOV, and

  19. Thermal error analysis and compensation for digital image/volume correlation

    Science.gov (United States)

    Pan, Bing

    2018-02-01

    Digital image/volume correlation (DIC/DVC) rely on the digital images acquired by digital cameras and x-ray CT scanners to extract the motion and deformation of test samples. Regrettably, these imaging devices are unstable optical systems, whose imaging geometry may undergo unavoidable slight and continual changes due to self-heating effect or ambient temperature variations. Changes in imaging geometry lead to both shift and expansion in the recorded 2D or 3D images, and finally manifest as systematic displacement and strain errors in DIC/DVC measurements. Since measurement accuracy is always the most important requirement in various experimental mechanics applications, these thermal-induced errors (referred to as thermal errors) should be given serious consideration in order to achieve high accuracy, reproducible DIC/DVC measurements. In this work, theoretical analyses are first given to understand the origin of thermal errors. Then real experiments are conducted to quantify thermal errors. Three solutions are suggested to mitigate or correct thermal errors. Among these solutions, a reference sample compensation approach is highly recommended because of its easy implementation, high accuracy and in-situ error correction capability. Most of the work has appeared in our previously published papers, thus its originality is not claimed. Instead, this paper aims to give a comprehensive overview and more insights of our work on thermal error analysis and compensation for DIC/DVC measurements.

  20. National survey on dose data analysis in computed tomography.

    Science.gov (United States)

    Heilmaier, Christina; Treier, Reto; Merkle, Elmar Max; Alkhadi, Hatem; Weishaupt, Dominik; Schindera, Sebastian

    2018-05-28

    A nationwide survey was performed assessing current practice of dose data analysis in computed tomography (CT). All radiological departments in Switzerland were asked to participate in the on-line survey composed of 19 questions (16 multiple choice, 3 free text). It consisted of four sections: (1) general information on the department, (2) dose data analysis, (3) use of a dose management software (DMS) and (4) radiation protection activities. In total, 152 out of 241 Swiss radiological departments filled in the whole questionnaire (return rate, 63%). Seventy-nine per cent of the departments (n = 120/152) analyse dose data on a regular basis with considerable heterogeneity in the frequency (1-2 times per year, 45%, n = 54/120; every month, 35%, n = 42/120) and method of analysis. Manual analysis is carried out by 58% (n = 70/120) compared with 42% (n = 50/120) of departments using a DMS. Purchase of a DMS is planned by 43% (n = 30/70) of the departments with manual analysis. Real-time analysis of dose data is performed by 42% (n = 21/50) of the departments with a DMS; however, residents can access the DMS in clinical routine only in 20% (n = 10/50) of the departments. An interdisciplinary dose team, which among other things communicates dose data internally (63%, n = 76/120) and externally, is already implemented in 57% (n = 68/120) departments. Swiss radiological departments are committed to radiation safety. However, there is high heterogeneity among them regarding the frequency and method of dose data analysis as well as the use of DMS and radiation protection activities. • Swiss radiological departments are committed to and interest in radiation safety as proven by a 63% return rate of the survey. • Seventy-nine per cent of departments analyse dose data on a regular basis with differences in the frequency and method of analysis: 42% use a dose management software, while 58% currently perform manual dose data analysis. Of the latter, 43% plan to buy a dose

  1. Soft error modeling and analysis of the Neutron Intercepting Silicon Chip (NISC)

    International Nuclear Information System (INIS)

    Celik, Cihangir; Unlue, Kenan; Narayanan, Vijaykrishnan; Irwin, Mary J.

    2011-01-01

    Soft errors are transient errors caused due to excess charge carriers induced primarily by external radiations in the semiconductor devices. Soft error phenomena could be used to detect thermal neutrons with a neutron monitoring/detection system by enhancing soft error occurrences in the memory devices. This way, one can convert all semiconductor memory devices into neutron detection systems. Such a device is being developed at The Pennsylvania State University and named Neutron Intercepting Silicon Chip (NISC). The NISC is envisioning a miniature, power efficient, and active/passive operation neutron sensor/detector system. NISC aims to achieve this goal by introducing 10 B-enriched Borophosphosilicate Glass (BPSG) insulation layers in the semiconductor memories. In order to model and analyze the NISC, an analysis tool using Geant4 as the transport and tracking engine is developed for the simulation of the charged particle interactions in the semiconductor memory model, named NISC Soft Error Analysis Tool (NISCSAT). A simple model with 10 B-enriched layer on top of the lumped silicon region is developed in order to represent the semiconductor memory node. Soft error probability calculations were performed via the NISCSAT with both single node and array configurations to investigate device scaling by using different node dimensions in the model. Mono-energetic, mono-directional thermal and fast neutrons are used as the neutron sources. Soft error contribution due to the BPSG layer is also investigated with different 10 B contents and the results are presented in this paper.

  2. Development of safety analysis and constraint detection techniques for process interaction errors

    International Nuclear Information System (INIS)

    Fan, Chin-Feng; Tsai, Shang-Lin; Tseng, Wan-Hui

    2011-01-01

    Among the new failure modes introduced by computer into safety systems, the process interaction error is the most unpredictable and complicated failure mode, which may cause disastrous consequences. This paper presents safety analysis and constraint detection techniques for process interaction errors among hardware, software, and human processes. Among interaction errors, the most dreadful ones are those that involve run-time misinterpretation from a logic process. We call them the 'semantic interaction errors'. Such abnormal interaction is not adequately emphasized in current research. In our static analysis, we provide a fault tree template focusing on semantic interaction errors by checking conflicting pre-conditions and post-conditions among interacting processes. Thus, far-fetched, but highly risky, interaction scenarios involve interpretation errors can be identified. For run-time monitoring, a range of constraint types is proposed for checking abnormal signs at run time. We extend current constraints to a broader relational level and a global level, considering process/device dependencies and physical conservation rules in order to detect process interaction errors. The proposed techniques can reduce abnormal interactions; they can also be used to assist in safety-case construction.

  3. Development of safety analysis and constraint detection techniques for process interaction errors

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Chin-Feng, E-mail: csfanc@saturn.yzu.edu.tw [Computer Science and Engineering Dept., Yuan-Ze University, Taiwan (China); Tsai, Shang-Lin; Tseng, Wan-Hui [Computer Science and Engineering Dept., Yuan-Ze University, Taiwan (China)

    2011-02-15

    Among the new failure modes introduced by computer into safety systems, the process interaction error is the most unpredictable and complicated failure mode, which may cause disastrous consequences. This paper presents safety analysis and constraint detection techniques for process interaction errors among hardware, software, and human processes. Among interaction errors, the most dreadful ones are those that involve run-time misinterpretation from a logic process. We call them the 'semantic interaction errors'. Such abnormal interaction is not adequately emphasized in current research. In our static analysis, we provide a fault tree template focusing on semantic interaction errors by checking conflicting pre-conditions and post-conditions among interacting processes. Thus, far-fetched, but highly risky, interaction scenarios involve interpretation errors can be identified. For run-time monitoring, a range of constraint types is proposed for checking abnormal signs at run time. We extend current constraints to a broader relational level and a global level, considering process/device dependencies and physical conservation rules in order to detect process interaction errors. The proposed techniques can reduce abnormal interactions; they can also be used to assist in safety-case construction.

  4. A stochastic dynamic model for human error analysis in nuclear power plants

    Science.gov (United States)

    Delgado-Loperena, Dharma

    Nuclear disasters like Three Mile Island and Chernobyl indicate that human performance is a critical safety issue, sending a clear message about the need to include environmental press and competence aspects in research. This investigation was undertaken to serve as a roadmap for studying human behavior through the formulation of a general solution equation. The theoretical model integrates models from two heretofore-disassociated disciplines (behavior specialists and technical specialists), that historically have independently studied the nature of error and human behavior; including concepts derived from fractal and chaos theory; and suggests re-evaluation of base theory regarding human error. The results of this research were based on comprehensive analysis of patterns of error, with the omnipresent underlying structure of chaotic systems. The study of patterns lead to a dynamic formulation, serving for any other formula used to study human error consequences. The search for literature regarding error yielded insight for the need to include concepts rooted in chaos theory and strange attractors---heretofore unconsidered by mainstream researchers who investigated human error in nuclear power plants or those who employed the ecological model in their work. The study of patterns obtained from the rupture of a steam generator tube (SGTR) event simulation, provided a direct application to aspects of control room operations in nuclear power plant operations. In doing so, the conceptual foundation based in the understanding of the patterns of human error analysis can be gleaned, resulting in reduced and prevent undesirable events.

  5. Estimation of the human error probabilities in the human reliability analysis

    International Nuclear Information System (INIS)

    Liu Haibin; He Xuhong; Tong Jiejuan; Shen Shifei

    2006-01-01

    Human error data is an important issue of human reliability analysis (HRA). Using of Bayesian parameter estimation, which can use multiple information, such as the historical data of NPP and expert judgment data to modify the human error data, could get the human error data reflecting the real situation of NPP more truly. This paper, using the numeric compute program developed by the authors, presents some typical examples to illustrate the process of the Bayesian parameter estimation in HRA and discusses the effect of different modification data on the Bayesian parameter estimation. (authors)

  6. SYNTACTIC ERRORS ANALYSIS IN THE CASUAL CONVERSATION 60 COMMITED BY TWO SENIOR HIGH STUDENTS

    Directory of Open Access Journals (Sweden)

    Anjar Setiawan

    2017-12-01

    Full Text Available Syntactic structures are the base of English grammar. This study was aimed to analyze the syntactic errors in the casual conversation commited by two senior high students of MAN 2 Semarang. The researcher used qualitative approach to analyze and interpret the meaning of casual conversation. Furthermore, the data collection had been transcribed and analyzed based on the areas of syntactic errors analysis. The findings of the study showed that all areas of syntactic errors happened during the conversation, included auxiliaries, tenses, article, preposition, and conjunction. Both speakers also had a relatively weak vocabulary and their sentences which were sometimes incomprehensible by the interlocutor.

  7. Classification of Error-Diffused Halftone Images Based on Spectral Regression Kernel Discriminant Analysis

    Directory of Open Access Journals (Sweden)

    Zhigao Zeng

    2016-01-01

    Full Text Available This paper proposes a novel algorithm to solve the challenging problem of classifying error-diffused halftone images. We firstly design the class feature matrices, after extracting the image patches according to their statistics characteristics, to classify the error-diffused halftone images. Then, the spectral regression kernel discriminant analysis is used for feature dimension reduction. The error-diffused halftone images are finally classified using an idea similar to the nearest centroids classifier. As demonstrated by the experimental results, our method is fast and can achieve a high classification accuracy rate with an added benefit of robustness in tackling noise.

  8. Human error analysis project (HEAP) - The fourth pilot study: verbal data for analysis of operator performance

    International Nuclear Information System (INIS)

    Braarud, Per Oeyvind; Droeyvoldsmo, Asgeir; Hollnagel, Erik

    1997-06-01

    This report is the second report from the Pilot study No. 4 within the Human Error Analyses Project (HEAP). The overall objective of HEAP is to provide a better understanding and explicit modelling of how and why ''cognitive errors'' occur. This study investigated the contribution from different verbal data sources for analysis of control room operator's performance. Operator's concurrent verbal report, retrospective verbal report, and process expert's comments were compared for their contribution to an operator performance measure. This study looked into verbal protocols for single operator and for team. The main findings of the study were that all the three verbal data sources could be used to study performance. There was a relative high overlap between the data sources, but also a unique contribution from each source. There was a common pattern in the types of operator activities the data sources gave information about. The operator's concurrent protocol overall contained slightly more information on the operator's activities than the other two verbal sources. The study also showed that concurrent verbal protocol is feasible and useful for analysis of team's activities during a scenario. (author)

  9. Wavefront-error evaluation by mathematical analysis of experimental Foucault-test data

    Science.gov (United States)

    Wilson, R. G.

    1975-01-01

    The diffraction theory of the Foucault test provides an integral formula expressing the complex amplitude and irradiance distribution in the Foucault pattern of a test mirror (lens) as a function of wavefront error. Recent literature presents methods of inverting this formula to express wavefront error in terms of irradiance in the Foucault pattern. The present paper describes a study in which the inversion formulation was applied to photometric Foucault-test measurements on a nearly diffraction-limited mirror to determine wavefront errors for direct comparison with ones determined from scatter-plate interferometer measurements. The results affirm the practicability of the Foucault test for quantitative wavefront analysis of very small errors, and they reveal the fallacy of the prevalent belief that the test is limited to qualitative use only. Implications of the results with regard to optical testing and the potential use of the Foucault test for wavefront analysis in orbital space telescopes are discussed.

  10. Error of semiclassical eigenvalues in the semiclassical limit - an asymptotic analysis of the Sinai billiard

    Science.gov (United States)

    Dahlqvist, Per

    1999-10-01

    We estimate the error in the semiclassical trace formula for the Sinai billiard under the assumption that the largest source of error is due to penumbra diffraction: namely, diffraction effects for trajectories passing within a distance Ricons/Journals/Common/cdot" ALT="cdot" ALIGN="TOP"/>O((kR)-2/3) to the disc and trajectories being scattered in very forward directions. Here k is the momentum and R the radius of the scatterer. The semiclassical error is estimated by perturbing the Berry-Keating formula. The analysis necessitates an asymptotic analysis of very long periodic orbits. This is obtained within an approximation originally due to Baladi, Eckmann and Ruelle. We find that the average error, for sufficiently large values of kR, will exceed the mean level spacing.

  11. Study on Network Error Analysis and Locating based on Integrated Information Decision System

    Science.gov (United States)

    Yang, F.; Dong, Z. H.

    2017-10-01

    Integrated information decision system (IIDS) integrates multiple sub-system developed by many facilities, including almost hundred kinds of software, which provides with various services, such as email, short messages, drawing and sharing. Because the under-layer protocols are different, user standards are not unified, many errors are occurred during the stages of setup, configuration, and operation, which seriously affect the usage. Because the errors are various, which may be happened in different operation phases, stages, TCP/IP communication protocol layers, sub-system software, it is necessary to design a network error analysis and locating tool for IIDS to solve the above problems. This paper studies on network error analysis and locating based on IIDS, which provides strong theory and technology supports for the running and communicating of IIDS.

  12. Analysis of the of bones through 3D computerized tomography

    International Nuclear Information System (INIS)

    Lima, I.; Lopes, R.T.; Oliveira, L.F.; Alves, J.M.

    2009-01-01

    This work shows the analysis of the internal structure of the bones samples through 3D micro tomography technique (3D-μTC). The comprehension of the bone structure is particularly important when related to osteoporosis diagnosis because this implies in a deterioration of the trabecular bone architecture, which increases the fragility and the possibility to have bone fractures. Two bone samples (human calcaneous and Wistar rat femur) were used, and the method was a radiographic system in real time with an X Ray microfocus tube. The quantifications parameters are based on stereological principles and they are five: a bone volume fraction, trabecular number, the ratio between surface and bone volume, the trabecular thickness and the trabecular separation. The quantifications were done with a program developed especially for this purpose in Nuclear Instrumentation Laboratory - COPPE/UFRJ. This program uses as input the 3D reconstructions images and generates a table with the quantifications. The results of the human calcaneous quantifications are presented in tables 1 and 2, and the 3D reconstructions are illustrated in Figure 5. The Figure 6 illustrate the 2D reconstructed image and the Figure 7 the 3D visualization respectively of the Wistar femur sample. The obtained results show that the 3D-μTC is a powerful technique that can be used to analyze bone microstructures. (author)

  13. STEM tomography analysis of the trypanosome transition zone.

    Science.gov (United States)

    Trépout, Sylvain; Tassin, Anne-Marie; Marco, Sergio; Bastin, Philippe

    2018-04-01

    The protist Trypanosoma brucei is an emerging model for the study of cilia and flagella. Here, we used scanning transmission electron microscopy (STEM) tomography to describe the structure of the trypanosome transition zone (TZ). At the base of the TZ, nine transition fibres irradiate from the B microtubule of each doublet towards the membrane. The TZ adopts a 9 + 0 structure throughout its length of ∼300 nm and its lumen contains an electron-dense structure. The proximal portion of the TZ has an invariant length of 150 nm and is characterised by a collarette surrounding the membrane and the presence of electron-dense material between the membrane and the doublets. The distal portion exhibits more length variation (from 55 to 235 nm) and contains typical Y-links. STEM analysis revealed a more complex organisation of the Y-links compared to what was reported by conventional transmission electron microscopy. Observation of the very early phase of flagellum assembly demonstrated that the proximal portion and the collarette are assembled early during construction. The presence of the flagella connector that maintains the tip of the new flagellum to the side of the old was confirmed and additional filamentous structures making contact with the membrane of the flagellar pocket were also detected. The structure and potential functions of the TZ in trypanosomes are discussed, as well as its mode of assembly. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Component Analysis of Errors on PERSIANN Precipitation Estimates over Urmia Lake Basin, IRAN

    Science.gov (United States)

    Ghajarnia, N.; Daneshkar Arasteh, P.; Liaghat, A. M.; Araghinejad, S.

    2016-12-01

    this product. Overall, we believe that different error component's analysis performed in this study, can substantially help any further local studies for post-calibration and bias reduction of PERSIANN estimations.

  15. Detecting medication errors in the New Zealand pharmacovigilance database: a retrospective analysis.

    Science.gov (United States)

    Kunac, Desireé L; Tatley, Michael V

    2011-01-01

    Despite the traditional focus being adverse drug reactions (ADRs), pharmacovigilance centres have recently been identified as a potentially rich and important source of medication error data. To identify medication errors in the New Zealand Pharmacovigilance database (Centre for Adverse Reactions Monitoring [CARM]), and to describe the frequency and characteristics of these events. A retrospective analysis of the CARM pharmacovigilance database operated by the New Zealand Pharmacovigilance Centre was undertaken for the year 1 January-31 December 2007. All reports, excluding those relating to vaccines, clinical trials and pharmaceutical company reports, underwent a preventability assessment using predetermined criteria. Those events deemed preventable were subsequently classified to identify the degree of patient harm, type of error, stage of medication use process where the error occurred and origin of the error. A total of 1412 reports met the inclusion criteria and were reviewed, of which 4.3% (61/1412) were deemed preventable. Not all errors resulted in patient harm: 29.5% (18/61) were 'no harm' errors but 65.5% (40/61) of errors were deemed to have been associated with some degree of patient harm (preventable adverse drug events [ADEs]). For 5.0% (3/61) of events, the degree of patient harm was unable to be determined as the patient outcome was unknown. The majority of preventable ADEs (62.5% [25/40]) occurred in adults aged 65 years and older. The medication classes most involved in preventable ADEs were antibacterials for systemic use and anti-inflammatory agents, with gastrointestinal and respiratory system disorders the most common adverse events reported. For both preventable ADEs and 'no harm' events, most errors were incorrect dose and drug therapy monitoring problems consisting of failures in detection of significant drug interactions, past allergies or lack of necessary clinical monitoring. Preventable events were mostly related to the prescribing and

  16. Review of human error analysis methodologies and case study for accident management

    International Nuclear Information System (INIS)

    Jung, Won Dae; Kim, Jae Whan; Lee, Yong Hee; Ha, Jae Joo

    1998-03-01

    In this research, we tried to establish the requirements for the development of a new human error analysis method. To achieve this goal, we performed a case study as following steps; 1. review of the existing HEA methods 2. selection of those methods which are considered to be appropriate for the analysis of operator's tasks in NPPs 3. choice of tasks for the application, selected for the case study: HRMS (Human reliability management system), PHECA (Potential Human Error Cause Analysis), CREAM (Cognitive Reliability and Error Analysis Method). And, as the tasks for the application, 'bleed and feed operation' and 'decision-making for the reactor cavity flooding' tasks are chosen. We measured the applicability of the selected methods to the NPP tasks, and evaluated the advantages and disadvantages between each method. The three methods are turned out to be applicable for the prediction of human error. We concluded that both of CREAM and HRMS are equipped with enough applicability for the NPP tasks, however, compared two methods. CREAM is thought to be more appropriate than HRMS from the viewpoint of overall requirements. The requirements for the new HEA method obtained from the study can be summarized as follows; firstly, it should deal with cognitive error analysis, secondly, it should have adequate classification system for the NPP tasks, thirdly, the description on the error causes and error mechanisms should be explicit, fourthly, it should maintain the consistency of the result by minimizing the ambiguity in each step of analysis procedure, fifty, it should be done with acceptable human resources. (author). 25 refs., 30 tabs., 4 figs

  17. Analysis of human error and organizational deficiency in events considering risk significance

    International Nuclear Information System (INIS)

    Lee, Yong Suk; Kim, Yoonik; Kim, Say Hyung; Kim, Chansoo; Chung, Chang Hyun; Jung, Won Dea

    2004-01-01

    In this study, we analyzed human and organizational deficiencies in the trip events of Korean nuclear power plants. K-HPES items were used in human error analysis, and the organizational factors by Jacobs and Haber were used for organizational deficiency analysis. We proposed the use of CCDP as a risk measure to consider risk information in prioritizing K-HPES items and organizational factors. Until now, the risk significance of events has not been considered in human error and organizational deficiency analysis. Considering the risk significance of events in the process of analysis is necessary for effective enhancement of nuclear power plant safety by focusing on causes of human error and organizational deficiencies that are associated with significant risk

  18. A human error analysis methodology, AGAPE-ET, for emergency tasks in nuclear power plants and its application

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Whan; Jung, Won Dea [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-03-01

    This report presents a procedurised human reliability analysis (HRA) methodology, AGAPE-ET (A Guidance And Procedure for Human Error Analysis for Emergency Tasks), for both qualitative error analysis and quantification of human error probability (HEP) of emergency tasks in nuclear power plants. The AGAPE-ET is based on the simplified cognitive model. By each cognitive function, error causes or error-likely situations have been identified considering the characteristics of the performance of each cognitive function and influencing mechanism of PIFs on the cognitive function. Then, error analysis items have been determined from the identified error causes or error-likely situations to help the analysts cue or guide overall human error analysis. A human error analysis procedure based on the error analysis items is organised. The basic scheme for the quantification of HEP consists in the multiplication of the BHEP assigned by the error analysis item and the weight from the influencing factors decision tree (IFDT) constituted by cognitive function. The method can be characterised by the structured identification of the weak points of the task required to perform and the efficient analysis process that the analysts have only to carry out with the necessary cognitive functions. The report also presents the the application of AFAPE-ET to 31 nuclear emergency tasks and its results. 42 refs., 7 figs., 36 tabs. (Author)

  19. Optical System Error Analysis and Calibration Method of High-Accuracy Star Trackers

    Directory of Open Access Journals (Sweden)

    Zheng You

    2013-04-01

    Full Text Available The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  20. Optical system error analysis and calibration method of high-accuracy star trackers.

    Science.gov (United States)

    Sun, Ting; Xing, Fei; You, Zheng

    2013-04-08

    The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  1. Error analysis and algorithm implementation for an improved optical-electric tracking device based on MEMS

    Science.gov (United States)

    Sun, Hong; Wu, Qian-zhong

    2013-09-01

    In order to improve the precision of optical-electric tracking device, proposing a kind of improved optical-electric tracking device based on MEMS, in allusion to the tracking error of gyroscope senor and the random drift, According to the principles of time series analysis of random sequence, establish AR model of gyro random error based on Kalman filter algorithm, then the output signals of gyro are multiple filtered with Kalman filter. And use ARM as micro controller servo motor is controlled by fuzzy PID full closed loop control algorithm, and add advanced correction and feed-forward links to improve response lag of angle input, Free-forward can make output perfectly follow input. The function of lead compensation link is to shorten the response of input signals, so as to reduce errors. Use the wireless video monitor module and remote monitoring software (Visual Basic 6.0) to monitor servo motor state in real time, the video monitor module gathers video signals, and the wireless video module will sent these signals to upper computer, so that show the motor running state in the window of Visual Basic 6.0. At the same time, take a detailed analysis to the main error source. Through the quantitative analysis of the errors from bandwidth and gyro sensor, it makes the proportion of each error in the whole error more intuitive, consequently, decrease the error of the system. Through the simulation and experiment results shows the system has good following characteristic, and it is very valuable for engineering application.

  2. The effect of decreasing computed tomography dosage on radiostereometric analysis (RSA) accuracy at the glenohumeral joint.

    Science.gov (United States)

    Fox, Anne-Marie V; Kedgley, Angela E; Lalone, Emily A; Johnson, James A; Athwal, George S; Jenkyn, Thomas R

    2011-11-10

    Standard, beaded radiostereometric analysis (RSA) and markerless RSA often use computed tomography (CT) scans to create three-dimensional (3D) bone models. However, ethical concerns exist due to risks associated with CT radiation exposure. Therefore, the aim of this study was to investigate the effect of decreasing CT dosage on RSA accuracy. Four cadaveric shoulder specimens were scanned using a normal-dose CT protocol and two low-dose protocols, where the dosage was decreased by 89% and 98%. 3D computer models of the humerus and scapula were created using each CT protocol. Bi-planar fluoroscopy was used to image five different static glenohumeral positions and two dynamic glenohumeral movements, of which a total of five static and four dynamic poses were selected for analysis. For standard RSA, negligible differences were found in bead (0.21±0.31mm) and bony landmark (2.31±1.90mm) locations when the CT dosage was decreased by 98% (p-values>0.167). For markerless RSA kinematic results, excellent agreement was found between the normal-dose and lowest-dose protocol, with all Spearman rank correlation coefficients greater than 0.95. Average root mean squared errors of 1.04±0.68mm and 2.42±0.81° were also found at this reduced dosage for static positions. In summary, CT dosage can be markedly reduced when performing shoulder RSA to minimize the risks of radiation exposure. Standard RSA accuracy was negligibly affected by the 98% CT dose reduction and for markerless RSA, the benefits of decreasing CT dosage to the subject outweigh the introduced errors. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Outcomes of a Failure Mode and Effects Analysis for medication errors in pediatric anesthesia.

    Science.gov (United States)

    Martin, Lizabeth D; Grigg, Eliot B; Verma, Shilpa; Latham, Gregory J; Rampersad, Sally E; Martin, Lynn D

    2017-06-01

    The Institute of Medicine has called for development of strategies to prevent medication errors, which are one important cause of preventable harm. Although the field of anesthesiology is considered a leader in patient safety, recent data suggest high medication error rates in anesthesia practice. Unfortunately, few error prevention strategies for anesthesia providers have been implemented. Using Toyota Production System quality improvement methodology, a multidisciplinary team observed 133 h of medication practice in the operating room at a tertiary care freestanding children's hospital. A failure mode and effects analysis was conducted to systematically deconstruct and evaluate each medication handling process step and score possible failure modes to quantify areas of risk. A bundle of five targeted countermeasures were identified and implemented over 12 months. Improvements in syringe labeling (73 to 96%), standardization of medication organization in the anesthesia workspace (0 to 100%), and two-provider infusion checks (23 to 59%) were observed. Medication error reporting improved during the project and was subsequently maintained. After intervention, the median medication error rate decreased from 1.56 to 0.95 per 1000 anesthetics. The frequency of medication error harm events reaching the patient also decreased. Systematic evaluation and standardization of medication handling processes by anesthesia providers in the operating room can decrease medication errors and improve patient safety. © 2017 John Wiley & Sons Ltd.

  4. Error Analysis of Satellite Precipitation-Driven Modeling of Flood Events in Complex Alpine Terrain

    Directory of Open Access Journals (Sweden)

    Yiwen Mei

    2016-03-01

    Full Text Available The error in satellite precipitation-driven complex terrain flood simulations is characterized in this study for eight different global satellite products and 128 flood events over the Eastern Italian Alps. The flood events are grouped according to two flood types: rain floods and flash floods. The satellite precipitation products and runoff simulations are evaluated based on systematic and random error metrics applied on the matched event pairs and basin-scale event properties (i.e., rainfall and runoff cumulative depth and time series shape. Overall, error characteristics exhibit dependency on the flood type. Generally, timing of the event precipitation mass center and dispersion of the time series derived from satellite precipitation exhibits good agreement with the reference; the cumulative depth is mostly underestimated. The study shows a dampening effect in both systematic and random error components of the satellite-driven hydrograph relative to the satellite-retrieved hyetograph. The systematic error in shape of the time series shows a significant dampening effect. The random error dampening effect is less pronounced for the flash flood events and the rain flood events with a high runoff coefficient. This event-based analysis of the satellite precipitation error propagation in flood modeling sheds light on the application of satellite precipitation in mountain flood hydrology.

  5. LEARNING FROM MISTAKES Error Analysis in the English Speech of Indonesian Tertiary Students

    Directory of Open Access Journals (Sweden)

    Imelda Gozali

    2017-12-01

    Full Text Available This study is part of a series of Classroom Action Research conducted with the aim of improving the English speech of students in one of the tertiary institutes in Indonesia. After some years of teaching English conversation, the writer noted that students made various types of errors in their speech, which can be classified generally into morphological, phonological, and lexical. While some of the errors are still generally acceptable, some others elicit laughter or inhibit comprehension altogether. Therefore, the writer is keen to analyze the more common errors made by the students, so as to be able to compile a teaching material that could be utilized to address those errors more effectively in future classes. This research used Error Analysis by Richards (1971 as the basis of classification. It was carried out in five classes with a total number of 80 students for a period of one semester (14 weeks. The results showed that most of the errors were phonological (errors in pronunciation, while others were morphological or grammatical in nature. This prompted the writer to design simple Phonics lessons for future classes.

  6. Adjustment of Measurements with Multiplicative Errors: Error Analysis, Estimates of the Variance of Unit Weight, and Effect on Volume Estimation from LiDAR-Type Digital Elevation Models

    Directory of Open Access Journals (Sweden)

    Yun Shi

    2014-01-01

    Full Text Available Modern observation technology has verified that measurement errors can be proportional to the true values of measurements such as GPS, VLBI baselines and LiDAR. Observational models of this type are called multiplicative error models. This paper is to extend the work of Xu and Shimada published in 2000 on multiplicative error models to analytical error analysis of quantities of practical interest and estimates of the variance of unit weight. We analytically derive the variance-covariance matrices of the three least squares (LS adjustments, the adjusted measurements and the corrections of measurements in multiplicative error models. For quality evaluation, we construct five estimators for the variance of unit weight in association of the three LS adjustment methods. Although LiDAR measurements are contaminated with multiplicative random errors, LiDAR-based digital elevation models (DEM have been constructed as if they were of additive random errors. We will simulate a model landslide, which is assumed to be surveyed with LiDAR, and investigate the effect of LiDAR-type multiplicative error measurements on DEM construction and its effect on the estimate of landslide mass volume from the constructed DEM.

  7. Optical coherence tomography signal analysis: LIDAR like equation and inverse methods

    International Nuclear Information System (INIS)

    Amaral, Marcello Magri

    2012-01-01

    Optical Coherence Tomography (OCT) is based on the media backscattering properties in order to obtain tomographic images. In a similar way, LIDAR (Light Detection and Range) technique uses these properties to determine atmospheric characteristics, specially the signal extinction coefficient. Exploring this similarity allowed the application of signal inversion methods to the OCT images, allowing to construct images based in the extinction coefficient, original result until now. The goal of this work was to study, propose, develop and implement algorithms based on OCT signal inversion methodologies with the aim of determine the extinction coefficient as a function of depth. Three inversion methods were used and implemented in LABView R : slope, boundary point and optical depth. Associated errors were studied and real samples (homogeneous and stratified) were used for two and three dimension analysis. The extinction coefficient images obtained from the optical depth method were capable to differentiate air from the sample. The images were studied applying PCA and cluster analysis that established the methodology strength in determining the sample's extinction coefficient value. Moreover, the optical depth methodology was applied to study the hypothesis that there is some correlation between signal extinction coefficient and the enamel teeth demineralization during a cariogenic process. By applying this methodology, it was possible to observe the variation of the extinction coefficient as depth function and its correlation with microhardness variation, showing that in deeper layers its values tends to a healthy tooth values, behaving as the same way that the microhardness. (author)

  8. Detailed semantic analyses of human error incidents occurring at nuclear power plants. Extraction of periodical transition of error occurrence patterns by applying multivariate analysis

    International Nuclear Information System (INIS)

    Hirotsu, Yuko; Suzuki, Kunihiko; Takano, Kenichi; Kojima, Mitsuhiro

    2000-01-01

    It is essential for preventing the recurrence of human error incidents to analyze and evaluate them with the emphasis on human factor. Detailed and structured analyses of all incidents at domestic nuclear power plants (NPPs) reported during last 31 years have been conducted based on J-HPES, in which total 193 human error cases are identified. Results obtained by the analyses have been stored into the J-HPES database. In the previous study, by applying multivariate analysis to above case studies, it was suggested that there were several occurrence patterns identified of how errors occur at NPPs. It was also clarified that the causes related to each human error are different depending on age of their occurrence. This paper described the obtained results in respects of periodical transition of human error occurrence patterns. By applying multivariate analysis to the above data, it was suggested there were two types of error occurrence patterns as to each human error type. First type is common occurrence patterns, not depending on the age, and second type is the one influenced by periodical characteristics. (author)

  9. CUSUM-Logistic Regression analysis for the rapid detection of errors in clinical laboratory test results.

    Science.gov (United States)

    Sampson, Maureen L; Gounden, Verena; van Deventer, Hendrik E; Remaley, Alan T

    2016-02-01

    The main drawback of the periodic analysis of quality control (QC) material is that test performance is not monitored in time periods between QC analyses, potentially leading to the reporting of faulty test results. The objective of this study was to develop a patient based QC procedure for the more timely detection of test errors. Results from a Chem-14 panel measured on the Beckman LX20 analyzer were used to develop the model. Each test result was predicted from the other 13 members of the panel by multiple regression, which resulted in correlation coefficients between the predicted and measured result of >0.7 for 8 of the 14 tests. A logistic regression model, which utilized the measured test result, the predicted test result, the day of the week and time of day, was then developed for predicting test errors. The output of the logistic regression was tallied by a daily CUSUM approach and used to predict test errors, with a fixed specificity of 90%. The mean average run length (ARL) before error detection by CUSUM-Logistic Regression (CSLR) was 20 with a mean sensitivity of 97%, which was considerably shorter than the mean ARL of 53 (sensitivity 87.5%) for a simple prediction model that only used the measured result for error detection. A CUSUM-Logistic Regression analysis of patient laboratory data can be an effective approach for the rapid and sensitive detection of clinical laboratory errors. Published by Elsevier Inc.

  10. Linear and nonlinear magnetic error measurements using action and phase jump analysis

    Directory of Open Access Journals (Sweden)

    Javier F. Cardona

    2009-01-01

    Full Text Available “Action and phase jump” analysis is presented—a beam based method that uses amplitude and phase knowledge of a particle trajectory to locate and measure magnetic errors in an accelerator lattice. The expected performance of the method is first tested using single-particle simulations in the optical lattice of the Relativistic Heavy Ion Collider (RHIC. Such simulations predict that under ideal conditions typical quadrupole errors can be estimated within an uncertainty of 0.04%. Other simulations suggest that sextupole errors can be estimated within a 3% uncertainty. Then the action and phase jump analysis is applied to real RHIC orbits with known quadrupole errors, and to real Super Proton Synchrotron (SPS orbits with known sextupole errors. It is possible to estimate the strength of a skew quadrupole error from measured RHIC orbits within a 1.2% uncertainty, and to estimate the strength of a strong sextupole component from the measured SPS orbits within a 7% uncertainty.

  11. On Kolmogorov asymptotics of estimators of the misclassification error rate in linear discriminant analysis

    KAUST Repository

    Zollanvari, Amin

    2013-05-24

    We provide a fundamental theorem that can be used in conjunction with Kolmogorov asymptotic conditions to derive the first moments of well-known estimators of the actual error rate in linear discriminant analysis of a multivariate Gaussian model under the assumption of a common known covariance matrix. The estimators studied in this paper are plug-in and smoothed resubstitution error estimators, both of which have not been studied before under Kolmogorov asymptotic conditions. As a result of this work, we present an optimal smoothing parameter that makes the smoothed resubstitution an unbiased estimator of the true error. For the sake of completeness, we further show how to utilize the presented fundamental theorem to achieve several previously reported results, namely the first moment of the resubstitution estimator and the actual error rate. We provide numerical examples to show the accuracy of the succeeding finite sample approximations in situations where the number of dimensions is comparable or even larger than the sample size.

  12. Statistical analysis with measurement error or misclassification strategy, method and application

    CERN Document Server

    Yi, Grace Y

    2017-01-01

    This monograph on measurement error and misclassification covers a broad range of problems and emphasizes unique features in modeling and analyzing problems arising from medical research and epidemiological studies. Many measurement error and misclassification problems have been addressed in various fields over the years as well as with a wide spectrum of data, including event history data (such as survival data and recurrent event data), correlated data (such as longitudinal data and clustered data), multi-state event data, and data arising from case-control studies. Statistical Analysis with Measurement Error or Misclassification: Strategy, Method and Application brings together assorted methods in a single text and provides an update of recent developments for a variety of settings. Measurement error effects and strategies of handling mismeasurement for different models are closely examined in combination with applications to specific problems. Readers with diverse backgrounds and objectives can utilize th...

  13. Writing Skill and Categorical Error Analysis: A Study of First Year Undergraduate University Students

    Directory of Open Access Journals (Sweden)

    Adnan Satariyan

    2014-09-01

    Full Text Available Abstract This study identifies and analyses the common errors in writing skill of the first year students of Azad University of South Tehran Branch in relation to their first language (L1, the type of high school they graduated, and their exposure to media and technology in order to learn English. It also determines the categories in which the errors are committed (content, organisation/discourse, vocabulary, mechanics, or syntax and whether or not there is a significant difference in the percentage of errors committed and these categories. Participants of this study are 190 first year students that are asked to write an essay. An error analysis model adapted from Brown (2001 and Gayeta (2002 is then used to evaluate the essay writings in terms of content, organisation, vocabulary, mechanics, and syntax or language use. The results of the study show that the students have greater difficulties in organisation, content, and vocabulary and experience less difficulties in mechanics and syntax.

  14. A Posteriori Error Analysis of Stochastic Differential Equations Using Polynomial Chaos Expansions

    KAUST Repository

    Butler, T.; Dawson, C.; Wildey, T.

    2011-01-01

    We develop computable a posteriori error estimates for linear functionals of a solution to a general nonlinear stochastic differential equation with random model/source parameters. These error estimates are based on a variational analysis applied to stochastic Galerkin methods for forward and adjoint problems. The result is a representation for the error estimate as a polynomial in the random model/source parameter. The advantage of this method is that we use polynomial chaos representations for the forward and adjoint systems to cheaply produce error estimates by simple evaluation of a polynomial. By comparison, the typical method of producing such estimates requires repeated forward/adjoint solves for each new choice of random parameter. We present numerical examples showing that there is excellent agreement between these methods. © 2011 Society for Industrial and Applied Mathematics.

  15. On Kolmogorov asymptotics of estimators of the misclassification error rate in linear discriminant analysis

    KAUST Repository

    Zollanvari, Amin; Genton, Marc G.

    2013-01-01

    We provide a fundamental theorem that can be used in conjunction with Kolmogorov asymptotic conditions to derive the first moments of well-known estimators of the actual error rate in linear discriminant analysis of a multivariate Gaussian model under the assumption of a common known covariance matrix. The estimators studied in this paper are plug-in and smoothed resubstitution error estimators, both of which have not been studied before under Kolmogorov asymptotic conditions. As a result of this work, we present an optimal smoothing parameter that makes the smoothed resubstitution an unbiased estimator of the true error. For the sake of completeness, we further show how to utilize the presented fundamental theorem to achieve several previously reported results, namely the first moment of the resubstitution estimator and the actual error rate. We provide numerical examples to show the accuracy of the succeeding finite sample approximations in situations where the number of dimensions is comparable or even larger than the sample size.

  16. Learning about Expectation Violation from Prediction Error Paradigms – A Meta-Analysis on Brain Processes Following a Prediction Error

    Directory of Open Access Journals (Sweden)

    Lisa D’Astolfo

    2017-07-01

    Full Text Available Modifying patients’ expectations by exposing them to expectation violation situations (thus maximizing the difference between the expected and the actual situational outcome is proposed to be a crucial mechanism for therapeutic success for a variety of different mental disorders. However, clinical observations suggest that patients often maintain their expectations regardless of experiences contradicting their expectations. It remains unclear which information processing mechanisms lead to modification or persistence of patients’ expectations. Insight in the processing could be provided by Neuroimaging studies investigating prediction error (PE, i.e., neuronal reactions to non-expected stimuli. Two methods are often used to investigate the PE: (1 paradigms, in which participants passively observe PEs (”passive” paradigms and (2 paradigms, which encourage a behavioral adaptation following a PE (“active” paradigms. These paradigms are similar to the methods used to induce expectation violations in clinical settings: (1 the confrontation with an expectation violation situation and (2 an enhanced confrontation in which the patient actively challenges his expectation. We used this similarity to gain insight in the different neuronal processing of the two PE paradigms. We performed a meta-analysis contrasting neuronal activity of PE paradigms encouraging a behavioral adaptation following a PE and paradigms enforcing passiveness following a PE. We found more neuronal activity in the striatum, the insula and the fusiform gyrus in studies encouraging behavioral adaptation following a PE. Due to the involvement of reward assessment and avoidance learning associated with the striatum and the insula we propose that the deliberate execution of action alternatives following a PE is associated with the integration of new information into previously existing expectations, therefore leading to an expectation change. While further research is needed

  17. Soft error evaluation and vulnerability analysis in Xilinx Zynq-7010 system-on chip

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xuecheng; He, Chaohui; Liu, Shuhuan, E-mail: liushuhuan@mail.xjtu.edu.cn; Zhang, Yao; Li, Yonghong; Xiong, Ceng; Tan, Pengkang

    2016-09-21

    Radiation-induced soft errors are an increasingly important threat to the reliability of modern electronic systems. In order to evaluate system-on chip's reliability and soft error, the fault tree analysis method was used in this work. The system fault tree was constructed based on Xilinx Zynq-7010 All Programmable SoC. Moreover, the soft error rates of different components in Zynq-7010 SoC were tested by americium-241 alpha radiation source. Furthermore, some parameters that used to evaluate the system's reliability and safety were calculated using Isograph Reliability Workbench 11.0, such as failure rate, unavailability and mean time to failure (MTTF). According to fault tree analysis for system-on chip, the critical blocks and system reliability were evaluated through the qualitative and quantitative analysis.

  18. Analysis on optical heterodyne frequency error of full-field heterodyne interferometer

    Science.gov (United States)

    Li, Yang; Zhang, Wenxi; Wu, Zhou; Lv, Xiaoyu; Kong, Xinxin; Guo, Xiaoli

    2017-06-01

    The full-field heterodyne interferometric measurement technology is beginning better applied by employing low frequency heterodyne acousto-optical modulators instead of complex electro-mechanical scanning devices. The optical element surface could be directly acquired by synchronously detecting the received signal phases of each pixel, because standard matrix detector as CCD and CMOS cameras could be used in heterodyne interferometer. Instead of the traditional four-step phase shifting phase calculating, Fourier spectral analysis method is used for phase extracting which brings lower sensitivity to sources of uncertainty and higher measurement accuracy. In this paper, two types of full-field heterodyne interferometer are described whose advantages and disadvantages are also specified. Heterodyne interferometer has to combine two different frequency beams to produce interference, which brings a variety of optical heterodyne frequency errors. Frequency mixing error and beat frequency error are two different kinds of inescapable heterodyne frequency errors. In this paper, the effects of frequency mixing error to surface measurement are derived. The relationship between the phase extraction accuracy and the errors are calculated. :: The tolerance of the extinction ratio of polarization splitting prism and the signal-to-noise ratio of stray light is given. The error of phase extraction by Fourier analysis that caused by beat frequency shifting is derived and calculated. We also propose an improved phase extraction method based on spectrum correction. An amplitude ratio spectrum correction algorithm with using Hanning window is used to correct the heterodyne signal phase extraction. The simulation results show that this method can effectively suppress the degradation of phase extracting caused by beat frequency error and reduce the measurement uncertainty of full-field heterodyne interferometer.

  19. Error Analysis: How Precise is Fused Deposition Modeling in Fabrication of Bone Models in Comparison to the Parent Bones?

    Science.gov (United States)

    Reddy, M V; Eachempati, Krishnakiran; Gurava Reddy, A V; Mugalur, Aakash

    2018-01-01

    Rapid prototyping (RP) is used widely in dental and faciomaxillary surgery with anecdotal uses in orthopedics. The purview of RP in orthopedics is vast. However, there is no error analysis reported in the literature on bone models generated using office-based RP. This study evaluates the accuracy of fused deposition modeling (FDM) using standard tessellation language (STL) files and errors generated during the fabrication of bone models. Nine dry bones were selected and were computed tomography (CT) scanned. STL files were procured from the CT scans and three-dimensional (3D) models of the bones were printed using our in-house FDM based 3D printer using Acrylonitrile Butadiene Styrene (ABS) filament. Measurements were made on the bone and 3D models according to data collection procedures for forensic skeletal material. Statistical analysis was performed to establish interobserver co-relation for measurements on dry bones and the 3D bone models. Statistical analysis was performed using SPSS version 13.0 software to analyze the collected data. The inter-observer reliability was established using intra-class coefficient for both the dry bones and the 3D models. The mean of absolute difference is 0.4 that is very minimal. The 3D models are comparable to the dry bones. STL file dependent FDM using ABS material produces near-anatomical 3D models. The high 3D accuracy hold a promise in the clinical scenario for preoperative planning, mock surgery, and choice of implants and prostheses, especially in complicated acetabular trauma and complex hip surgeries.

  20. Error analysis: How precise is fused deposition modeling in fabrication of bone models in comparison to the parent bones?

    Directory of Open Access Journals (Sweden)

    M V Reddy

    2018-01-01

    Full Text Available Background: Rapid prototyping (RP is used widely in dental and faciomaxillary surgery with anecdotal uses in orthopedics. The purview of RP in orthopedics is vast. However, there is no error analysis reported in the literature on bone models generated using office-based RP. This study evaluates the accuracy of fused deposition modeling (FDM using standard tessellation language (STL files and errors generated during the fabrication of bone models. Materials and Methods: Nine dry bones were selected and were computed tomography (CT scanned. STL files were procured from the CT scans and three-dimensional (3D models of the bones were printed using our in-house FDM based 3D printer using Acrylonitrile Butadiene Styrene (ABS filament. Measurements were made on the bone and 3D models according to data collection procedures for forensic skeletal material. Statistical analysis was performed to establish interobserver co-relation for measurements on dry bones and the 3D bone models. Statistical analysis was performed using SPSS version 13.0 software to analyze the collected data. Results: The inter-observer reliability was established using intra-class coefficient for both the dry bones and the 3D models. The mean of absolute difference is 0.4 that is very minimal. The 3D models are comparable to the dry bones. Conclusions: STL file dependent FDM using ABS material produces near-anatomical 3D models. The high 3D accuracy hold a promise in the clinical scenario for preoperative planning, mock surgery, and choice of implants and prostheses, especially in complicated acetabular trauma and complex hip surgeries.

  1. Theory of error for target factor analysis with applications to mass spectrometry and nuclear magnetic resonance spectrometry

    International Nuclear Information System (INIS)

    Malinowski, E.R.

    1978-01-01

    Based on the theory of error for abstract factor analysis described earlier, a theory of error for target factor analysis is developed. The theory shows how the error in the data matrix mixes with the error in the target test vector. The apparent error in a target test is found to be a vector sum of the real error in the target vector and the real error in the predicted vector. The theory predicts the magnitudes of these errors without requiring any a priori knowledge of the error in the data matrix or the target vector. A reliability function and a spoil function are developed for the purpose of assessing the validity and the worthiness of a target vector. Examples from model data, mass spectrometry and nuclear magnetic resonance spectrometry are presented. (Auth.)

  2. Analysis of concrete material through gamma ray computerized tomography

    International Nuclear Information System (INIS)

    Oliveira Junior, J.M. de

    2004-01-01

    Computerized Tomography (CT) refers to the cross sectional imaging of an object from both transmission or reflection data collected by illuminating the object from many different directions. The most important contribution of CT is to greatly improve abilities to distinguish regions with different gamma ray transmittance and to separate over-lying structures. The mathematical problem of the CT imaging is that of estimating an image from its projections. These projections can represent, for example, the linear attenuation coefficient of γ-rays along the path of the ray. In this work we will present some new results obtained by using tomographic techniques to analyze column samples of concrete to check the distribution of various materials and structural problems. These concrete samples were made using different proportions of stone, sand and cement. Another set of samples with different proportions of sand and cement were also used to verify the outcome from the CT analysis and the differences between them. Those samples were prepared at the Material Laboratory of Faculdade de Engenharia de Sorocaba, following the same procedures used in real case of concrete tests. The projections used in this work was obtained by Mini Computerized Tomograph of Uniso (MTCU), located at the Experimental Nuclear Physics Laboratory at University of Sorocaba. This tomograph operates with a gamma ray source of 241 Am (photons of 60 keV and 100 mCi of intensity) and a NaI(Tl) solid state detector. The system features translation and rotation scanning modes, a 100 mm effective field of view, and 1 mm spatial resolution. The image reconstruction problem is solved using Discrete Filtered Backprojection (FBP). (author)

  3. Error Analysis in a Written Composition Análisis de errores en una composición escrita

    Directory of Open Access Journals (Sweden)

    David Alberto Londoño Vásquez

    2008-12-01

    Full Text Available Learners make errors in both comprehension and production. Some theoreticians have pointed out the difficulty of assigning the cause of failures in comprehension to an inadequate knowledge of a particular syntactic feature of a misunderstood utterance. Indeed, an error can be defined as a deviation from the norms of the target language. In this investigation, based on personal and professional experience, a written composition entitled "My Life in Colombia" will be analyzed based on clinical elicitation (CE research. CE involves getting the informant to produce data of any sort, for example, by means of a general interview or by asking the learner to write a composition. Some errors produced by a foreign language learner in her acquisition process will be analyzed, identifying the possible sources of these errors. Finally, four kinds of errors are classified: omission, addition, misinformation, and misordering.Los aprendices comenten errores tanto en la comprensión como en la producción. Algunos teóricos han identificado que la dificultad para clasificar las diferentes fallas en comprensión se debe al conocimiento inadecuado de una característica sintáctica particular. Por tanto, el error puede definirse como una desviación de las normas del idioma objetivo. En esta experiencia profesional se analizará una composición escrita sobre "Mi vida en Colombia" con base en la investigación a través de la elicitación clínica (EC. Esta se centra en cómo el informante produce datos de cualquier tipo, por ejemplo, a través de una entrevista general o solicitándole al aprendiz una composición escrita. Se analizarán algunos errores producidos por un aprendiz de una lengua extranjera en su proceso de adquisición, identificando sus posibles causas. Finalmente, se clasifican cuatro tipos de errores: omisión, adición, desinformación y yuxtaposición sintáctica.

  4. A Human Error Analysis Procedure for Identifying Potential Error Modes and Influencing Factors for Test and Maintenance Activities

    International Nuclear Information System (INIS)

    Kim, Jae Whan; Park, Jin Kyun

    2010-01-01

    Periodic or non-periodic test and maintenance (T and M) activities in large, complex systems such as nuclear power plants (NPPs) are essential for sustaining stable and safe operation of the systems. On the other hand, it also has been raised that human erroneous actions that might occur during T and M activities has the possibility of incurring unplanned reactor trips (RTs) or power derate, making safety-related systems unavailable, or making the reliability of components degraded. Contribution of human errors during normal and abnormal activities of NPPs to the unplanned RTs is known to be about 20% of the total events. This paper introduces a procedure for predictively analyzing human error potentials when maintenance personnel perform T and M tasks based on a work procedure or their work plan. This procedure helps plant maintenance team prepare for plausible human errors. The procedure to be introduced is focusing on the recurrent error forms (or modes) in execution-based errors such as wrong object, omission, too little, and wrong action

  5. Human error and the problem of causality in analysis of accidents

    DEFF Research Database (Denmark)

    Rasmussen, Jens

    1990-01-01

    , designers or managers have played a major role. There are, however, several basic problems in analysis of accidents and identification of human error. This paper addresses the nature of causal explanations and the ambiguity of the rules applied for identification of the events to include in analysis......Present technology is characterized by complexity, rapid change and growing size of technical systems. This has caused increasing concern with the human involvement in system safety. Analyses of the major accidents during recent decades have concluded that human errors on part of operators...

  6. Optical Coherence Tomography in Alzheimer's Disease: A Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Gianluca Coppola

    Full Text Available Alzheimer's disease (AD is a neurodegenerative disorder, which is likely to start as mild cognitive impairment (MCI several years before the its full-blown clinical manifestation. Optical coherence tomography (OCT has been used to detect a loss in peripapillary retina nerve fiber layer (RNFL and a reduction in macular thickness and volume of people affected by MCI or AD. Here, we performed an aggregate meta-analysis combining results from different studies.Data sources were case-control studies published between January 2001 and August 2014 (identified through PubMed and Google Scholar databases that examined the RNFL thickness by means of OCT in AD and MCI patients compared with cognitively healthy controls.11 studies were identified, including 380 patients with AD, 68 with MCI and 293 healthy controls (HC. The studies suggest that the mean RNFL thickness is reduced in MCI (weighted mean differences in μm, WMD = -13.39, 95% CI: -17.34 to -9.45, p = 0.031 and, even more so, in AD (WMD = -15.95, 95% CI: -21.65 to -10.21, p<0.0001 patients compared to HC. RNFL in the 4 quadrants were all significantly thinner in AD superior (superior WMD = -24.0, 95% CI: -34.9 to -13.1, p<0.0001; inferior WMD = -20.8, 95% CI: -32.0 to -9.7, p<0.0001; nasal WMD = -14.7, 95% CI: -23.9 to -5.5, p<0.0001; and temporal WMD = -10.7, 95% CI: -19.9 to -1.4, p<0.0001; the same significant reduction in quadrant RNFL was observed in MCI patients compared with HC (Inferior WMD = -20.22, 95% CI: -30.41 to -10.03, p = 0.0001; nasal WMD = -7.4, 95% CI: -10.08 to -4.7, p = 0.0000; and temporal WMD = -6.88, 95% CI: -12.62 to -1.13, p = 0.01, with the exception of superior quadrant (WMD = -19.45, 95% CI: -40.23 to 1.32, p = 0.06.Results from the meta-analysis support the important role of OCT for RNFL analysis in monitoring the progression of AD and in assessing the effectiveness of purported AD treatments.

  7. The error analysis of the determination of the activity coefficients via the isopiestic method

    International Nuclear Information System (INIS)

    Zhou Jun; Chen Qiyuan; Fang Zheng; Liang Yizeng; Liu Shijun; Zhou Yong

    2005-01-01

    Error analysis is very important to experimental designs. The error analysis of the determination of activity coefficients for a binary system via the isopiestic method shows that the error sources include not only the experimental errors of the analyzed molalities and the measured osmotic coefficients, but also the deviation of the regressed values from the experimental data when the regression function is used. It also shows that the accurate chemical analysis of the molality of the test solution is important, and it is preferable to keep the error of the measured osmotic coefficients changeless in all isopiestic experiments including those experiments on the very dilute solutions. The isopiestic experiments on the dilute solutions are very important, and the lowest molality should be low enough so that a theoretical method can be used below the lowest molality. And it is necessary that the isopiestic experiment should be done on the test solutions of lower than 0.1 mol . kg -1 . For most electrolytes solutions, it is usually preferable to require the lowest molality to be less than 0.05 mol . kg -1 . Moreover, the experimental molalities of the test solutions should be firstly arranged by keeping the interval of the logarithms of the molalities nearly constant, and secondly more number of high molalities should be arranged, and we propose to arrange the experimental molalities greater than 1 mol . kg -1 according to some kind of the arithmetical progression of the intervals of the molalities. After experiments, the error of the calculated activity coefficients of the solutes could be calculated from the actually values of the errors of the measured isopiestic molalities and the deviations of the regressed values from the experimental values with our obtained equations

  8. Bit error rate analysis of free-space optical communication over general Malaga turbulence channels with pointing error

    KAUST Repository

    Alheadary, Wael Ghazy

    2016-12-24

    In this work, we present a bit error rate (BER) and achievable spectral efficiency (ASE) performance of a freespace optical (FSO) link with pointing errors based on intensity modulation/direct detection (IM/DD) and heterodyne detection over general Malaga turbulence channel. More specifically, we present exact closed-form expressions for adaptive and non-adaptive transmission. The closed form expressions are presented in terms of generalized power series of the Meijer\\'s G-function. Moreover, asymptotic closed form expressions are provided to validate our work. In addition, all the presented analytical results are illustrated using a selected set of numerical results.

  9. Error analysis of the crystal orientations obtained by the dictionary approach to EBSD indexing.

    Science.gov (United States)

    Ram, Farangis; Wright, Stuart; Singh, Saransh; De Graef, Marc

    2017-10-01

    The efficacy of the dictionary approach to Electron Back-Scatter Diffraction (EBSD) indexing was evaluated through the analysis of the error in the retrieved crystal orientations. EBSPs simulated by the Callahan-De Graef forward model were used for this purpose. Patterns were noised, distorted, and binned prior to dictionary indexing. Patterns with a high level of noise, with optical distortions, and with a 25 × 25 pixel size, when the error in projection center was 0.7% of the pattern width and the error in specimen tilt was 0.8°, were indexed with a 0.8° mean error in orientation. The same patterns, but 60 × 60 pixel in size, were indexed by the standard 2D Hough transform based approach with almost the same orientation accuracy. Optimal detection parameters in the Hough space were obtained by minimizing the orientation error. It was shown that if the error in detector geometry can be reduced to 0.1% in projection center and 0.1° in specimen tilt, the dictionary approach can retrieve a crystal orientation with a 0.2° accuracy. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. An analysis of error patterns in children′s backward digit recall in noise

    Directory of Open Access Journals (Sweden)

    Homira Osman

    2015-01-01

    Full Text Available The purpose of the study was to determine whether perceptual masking or cognitive processing accounts for a decline in working memory performance in the presence of competing speech. The types and patterns of errors made on the backward digit span in quiet and multitalker babble at -5 dB signal-to-noise ratio (SNR were analyzed. The errors were classified into two categories: item (if digits that were not presented in a list were repeated and order (if correct digits were repeated but in an incorrect order. Fifty five children with normal hearing were included. All the children were aged between 7 years and 10 years. Repeated measures of analysis of variance (RM-ANOVA revealed the main effects for error type and digit span length. In terms of listening condition interaction, it was found that the order errors occurred more frequently than item errors in the degraded listening condition compared to quiet. In addition, children had more difficulty recalling the correct order of intermediate items, supporting strong primacy and recency effects. Decline in children′s working memory performance was not primarily related to perceptual difficulties alone. The majority of errors was related to the maintenance of sequential order information, which suggests that reduced performance in competing speech may result from increased cognitive processing demands in noise.

  11. A Method and Support Tool for the Analysis of Human Error Hazards in Digital Devices

    International Nuclear Information System (INIS)

    Lee, Yong Hee; Kim, Seon Soo; Lee, Yong Hee

    2012-01-01

    In recent years, many nuclear power plants have adopted modern digital I and C technologies since they are expected to significantly improve their performance and safety. Modern digital technologies were expected to significantly improve both the economical efficiency and safety of nuclear power plants. However, the introduction of an advanced main control room (MCR) is accompanied with lots of changes in forms and features and differences through virtue of new digital devices. Many user-friendly displays and new features in digital devices are not enough to prevent human errors in nuclear power plants (NPPs). It may be an urgent to matter find the human errors potentials due to digital devices, and their detailed mechanisms. We can then consider them during the design of digital devices and their interfaces. The characteristics of digital technologies and devices may give many opportunities to the interface management, and can be integrated into a compact single workstation in an advanced MCR, such that workers can operate the plant with minimum burden under any operating condition. However, these devices may introduce new types of human errors, and thus we need a means to evaluate and prevent such errors, especially within digital devices for NPPs. This research suggests a new method named HEA-BIS (Human Error Analysis based on Interaction Segment) to confirm and detect human errors associated with digital devices. This method can be facilitated by support tools when used to ensure the safety when applying digital devices in NPPs

  12. Calculating potential error in sodium MRI with respect to the analysis of small objects.

    Science.gov (United States)

    Stobbe, Robert W; Beaulieu, Christian

    2018-06-01

    To facilitate correct interpretation of sodium MRI measurements, calculation of error with respect to rapid signal decay is introduced and combined with that of spatially correlated noise to assess volume-of-interest (VOI) 23 Na signal measurement inaccuracies, particularly for small objects. Noise and signal decay-related error calculations were verified using twisted projection imaging and a specially designed phantom with different sized spheres of constant elevated sodium concentration. As a demonstration, lesion signal measurement variation (5 multiple sclerosis participants) was compared with that predicted from calculation. Both theory and phantom experiment showed that VOI signal measurement in a large 10-mL, 314-voxel sphere was 20% less than expected on account of point-spread-function smearing when the VOI was drawn to include the full sphere. Volume-of-interest contraction reduced this error but increased noise-related error. Errors were even greater for smaller spheres (40-60% less than expected for a 0.35-mL, 11-voxel sphere). Image-intensity VOI measurements varied and increased with multiple sclerosis lesion size in a manner similar to that predicted from theory. Correlation suggests large underestimation of 23 Na signal in small lesions. Acquisition-specific measurement error calculation aids 23 Na MRI data analysis and highlights the limitations of current low-resolution methodologies. Magn Reson Med 79:2968-2977, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  13. An analysis of error patterns in children's backward digit recall in noise

    Science.gov (United States)

    Osman, Homira; Sullivan, Jessica R.

    2015-01-01

    The purpose of the study was to determine whether perceptual masking or cognitive processing accounts for a decline in working memory performance in the presence of competing speech. The types and patterns of errors made on the backward digit span in quiet and multitalker babble at -5 dB signal-to-noise ratio (SNR) were analyzed. The errors were classified into two categories: item (if digits that were not presented in a list were repeated) and order (if correct digits were repeated but in an incorrect order). Fifty five children with normal hearing were included. All the children were aged between 7 years and 10 years. Repeated measures of analysis of variance (RM-ANOVA) revealed the main effects for error type and digit span length. In terms of listening condition interaction it was found that the order errors occurred more frequently than item errors in the degraded listening condition compared to quiet. In addition, children had more difficulty recalling the correct order of intermediate items, supporting strong primacy and recency effects. Decline in children's working memory performance was not primarily related to perceptual difficulties alone. The majority of errors was related to the maintenance of sequential order information, which suggests that reduced performance in competing speech may result from increased cognitive processing demands in noise. PMID:26168949

  14. Medication errors in residential aged care facilities: a distributed cognition analysis of the information exchange process.

    Science.gov (United States)

    Tariq, Amina; Georgiou, Andrew; Westbrook, Johanna

    2013-05-01

    Medication safety is a pressing concern for residential aged care facilities (RACFs). Retrospective studies in RACF settings identify inadequate communication between RACFs, doctors, hospitals and community pharmacies as the major cause of medication errors. Existing literature offers limited insight about the gaps in the existing information exchange process that may lead to medication errors. The aim of this research was to explicate the cognitive distribution that underlies RACF medication ordering and delivery to identify gaps in medication-related information exchange which lead to medication errors in RACFs. The study was undertaken in three RACFs in Sydney, Australia. Data were generated through ethnographic field work over a period of five months (May-September 2011). Triangulated analysis of data primarily focused on examining the transformation and exchange of information between different media across the process. The findings of this study highlight the extensive scope and intense nature of information exchange in RACF medication ordering and delivery. Rather than attributing error to individual care providers, the explication of distributed cognition processes enabled the identification of gaps in three information exchange dimensions which potentially contribute to the occurrence of medication errors namely: (1) design of medication charts which complicates order processing and record keeping (2) lack of coordination mechanisms between participants which results in misalignment of local practices (3) reliance on restricted communication bandwidth channels mainly telephone and fax which complicates the information processing requirements. The study demonstrates how the identification of these gaps enhances understanding of medication errors in RACFs. Application of the theoretical lens of distributed cognition can assist in enhancing our understanding of medication errors in RACFs through identification of gaps in information exchange. Understanding

  15. Quantization error of CCD cameras and their influence on phase calculation in fringe pattern analysis.

    Science.gov (United States)

    Skydan, Oleksandr A; Lilley, Francis; Lalor, Michael J; Burton, David R

    2003-09-10

    We present an investigation into the phase errors that occur in fringe pattern analysis that are caused by quantization effects. When acquisition devices with a limited value of camera bit depth are used, there are a limited number of quantization levels available to record the signal. This may adversely affect the recorded signal and adds a potential source of instrumental error to the measurement system. Quantization effects also determine the accuracy that may be achieved by acquisition devices in a measurement system. We used the Fourier fringe analysis measurement technique. However, the principles can be applied equally well for other phase measuring techniques to yield a phase error distribution that is caused by the camera bit depth.

  16. Quantitative analysis of left ventricular strain using cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Buss, Sebastian J., E-mail: sebastian.buss@med.uni-heidelberg.de [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Schulz, Felix; Mereles, Derliz [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Hosch, Waldemar [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Galuschky, Christian; Schummers, Georg; Stapf, Daniel [TomTec Imaging Systems GmbH, Munich (Germany); Hofmann, Nina; Giannitsis, Evangelos; Hardt, Stefan E. [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Katus, Hugo A.; Korosoglou, Grigorios [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany)

    2014-03-15

    Objectives: To investigate whether cardiac computed tomography (CCT) can determine left ventricular (LV) radial, circumferential and longitudinal myocardial deformation in comparison to two-dimensional echocardiography in patients with congestive heart failure. Background: Echocardiography allows for accurate assessment of strain with high temporal resolution. A reduced strain is associated with a poor prognosis in cardiomyopathies. However, strain imaging is limited in patients with poor echogenic windows, so that, in selected cases, tomographic imaging techniques may be preferable for the evaluation of myocardial deformation. Methods: Consecutive patients (n = 27) with congestive heart failure who underwent a clinically indicated ECG-gated contrast-enhanced 64-slice dual-source CCT for the evaluation of the cardiac veins prior to cardiac resynchronization therapy (CRT) were included. All patients underwent additional echocardiography. LV radial, circumferential and longitudinal strain and strain rates were analyzed in identical midventricular short axis, 4-, 2- and 3-chamber views for both modalities using the same prototype software algorithm (feature tracking). Time for analysis was assessed for both modalities. Results: Close correlations were observed for both techniques regarding global strain (r = 0.93, r = 0.87 and r = 0.84 for radial, circumferential and longitudinal strain, respectively, p < 0.001 for all). Similar trends were observed for regional radial, longitudinal and circumferential strain (r = 0.88, r = 0.84 and r = 0.94, respectively, p < 0.001 for all). The number of non-diagnostic myocardial segments was significantly higher with echocardiography than with CCT (9.6% versus 1.9%, p < 0.001). In addition, the required time for complete quantitative strain analysis was significantly shorter for CCT compared to echocardiography (877 ± 119 s per patient versus 1105 ± 258 s per patient, p < 0.001). Conclusion: Quantitative assessment of LV strain

  17. Error analysis and system improvements in phase-stepping methods for photoelasticity

    International Nuclear Information System (INIS)

    Wenyan Ji

    1997-11-01

    In the past automated photoelasticity has been demonstrated to be one of the most efficient technique for determining the complete state of stress in a 3-D component. However, the measurement accuracy, which depends on many aspects of both the theoretical foundations and experimental procedures, has not been studied properly. The objective of this thesis is to reveal the intrinsic properties of the errors, provide methods for reducing them and finally improve the system accuracy. A general formulation for a polariscope with all the optical elements in an arbitrary orientation was deduced using the method of Mueller Matrices. The deduction of this formulation indicates an inherent connectivity among the optical elements and gives a knowledge of the errors. In addition, this formulation also shows a common foundation among the photoelastic techniques, consequently, these techniques share many common error sources. The phase-stepping system proposed by Patterson and Wang was used as an exemplar to analyse the errors and provide the proposed improvements. This system can be divided into four parts according to their function, namely the optical system, light source, image acquisition equipment and image analysis software. All the possible error sources were investigated separately and the methods for reducing the influence of the errors and improving the system accuracy are presented. To identify the contribution of each possible error to the final system output, a model was used to simulate the errors and analyse their consequences. Therefore the contribution to the results from different error sources can be estimated quantitatively and finally the accuracy of the systems can be improved. For a conventional polariscope, the system accuracy can be as high as 99.23% for the fringe order and the error less than 5 degrees for the isoclinic angle. The PSIOS system is limited to the low fringe orders. For a fringe order of less than 1.5, the accuracy is 94.60% for fringe

  18. M/T method based incremental encoder velocity measurement error analysis and self-adaptive error elimination algorithm

    DEFF Research Database (Denmark)

    Chen, Yangyang; Yang, Ming; Long, Jiang

    2017-01-01

    For motor control applications, the speed loop performance is largely depended on the accuracy of speed feedback signal. M/T method, due to its high theoretical accuracy, is the most widely used in incremental encoder adopted speed measurement. However, the inherent encoder optical grating error...

  19. Radiographic analysis of body composition by computerized axial tomography

    International Nuclear Information System (INIS)

    Heymsfield, S.B.

    1986-01-01

    Radiographic methods of evaluating body composition have been applied for over five decades. A marked improvement in this approach occurred in the mid-nineteen-seventies with the introduction of computerized axial tomography. High image contrast, cross-sectional imaging and rapid computerized data processing make this technique a sophisticated clinically applicable tool. (author)

  20. Circular Array of Magnetic Sensors for Current Measurement: Analysis for Error Caused by Position of Conductor.

    Science.gov (United States)

    Yu, Hao; Qian, Zheng; Liu, Huayi; Qu, Jiaqi

    2018-02-14

    This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of a circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as it is low-cost, light-weight, has a large linear range, wide bandwidth, and low noise. Especially, it has been claimed that such structure has excellent reduction ability for errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross-section, and the Earth's magnetic field. However, the positions of the current-carrying conductor-including un-centeredness and un-perpendicularity-have not been analyzed in detail until now. In this paper, for the purpose of having minimum measurement error, a theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle, and the number of magnetic sensors are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. Tunnel magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the details of the circular array of magnetic sensors for current measurement in practical situations.

  1. Identification of 'Point A' as the prevalent source of error in cephalometric analysis of lateral radiographs.

    Science.gov (United States)

    Grogger, P; Sacher, C; Weber, S; Millesi, G; Seemann, R

    2018-04-10

    Deviations in measuring dentofacial components in a lateral X-ray represent a major hurdle in the subsequent treatment of dysgnathic patients. In a retrospective study, we investigated the most prevalent source of error in the following commonly used cephalometric measurements: the angles Sella-Nasion-Point A (SNA), Sella-Nasion-Point B (SNB) and Point A-Nasion-Point B (ANB); the Wits appraisal; the anteroposterior dysplasia indicator (APDI); and the overbite depth indicator (ODI). Preoperative lateral radiographic images of patients with dentofacial deformities were collected and the landmarks digitally traced by three independent raters. Cephalometric analysis was automatically performed based on 1116 tracings. Error analysis identified the x-coordinate of Point A as the prevalent source of error in all investigated measurements, except SNB, in which it is not incorporated. In SNB, the y-coordinate of Nasion predominated error variance. SNB showed lowest inter-rater variation. In addition, our observations confirmed previous studies showing that landmark identification variance follows characteristic error envelopes in the highest number of tracings analysed up to now. Variance orthogonal to defining planes was of relevance, while variance parallel to planes was not. Taking these findings into account, orthognathic surgeons as well as orthodontists would be able to perform cephalometry more accurately and accomplish better therapeutic results. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  2. On the Relationship Between Anxiety and Error Monitoring: A meta-analysis and conceptual framework

    Directory of Open Access Journals (Sweden)

    Jason eMoser

    2013-08-01

    Full Text Available Research involving event-related brain potentials has revealed that anxiety is associated with enhanced error monitoring, as reflected in increased amplitude of the error-related negativity (ERN. The nature of the relationship between anxiety and error monitoring is unclear, however. Through meta-analysis and a critical review of the literature, we argue that anxious apprehension/worry is the dimension of anxiety most closely associated with error monitoring. Although, overall, anxiety demonstrated a robust, small-to-medium relationship with enhanced ERN (r = -.25, studies employing measures of anxious apprehension show a threefold greater effect size estimate (r = -.35 than those utilizing other measures of anxiety (r = -.09. Our conceptual framework helps explain this more specific relationship between anxiety and enhanced ERN and delineates the unique roles of worry, conflict processing, and modes of cognitive control. Collectively, our analysis suggests that enhanced ERN in anxiety results from the interplay of a decrease in processes supporting active goal maintenance and a compensatory increase in processes dedicated to transient reactivation of task goals on an as-needed basis when salient events (i.e., errors occur.

  3. Error Ratio Analysis: Alternate Mathematics Assessment for General and Special Educators.

    Science.gov (United States)

    Miller, James H.; Carr, Sonya C.

    1997-01-01

    Eighty-seven elementary students in grades four, five, and six, were administered a 30-item multiplication instrument to assess performance in computation across grade levels. An interpretation of student performance using error ratio analysis is provided and the use of this method with groups of students for instructional decision making is…

  4. Diction and Expression in Error Analysis Can Enhance Academic Writing of L2 University Students

    Science.gov (United States)

    Sajid, Muhammad

    2016-01-01

    Without proper linguistic competence in English language, academic writing is one of the most challenging tasks, especially, in various genre specific disciplines by L2 novice writers. This paper examines the role of diction and expression through error analysis in English language of L2 novice writers' academic writing in interdisciplinary texts…

  5. Error Analysis of Ia Supernova and Query on Cosmic Dark Energy

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Error Analysis of Ia Supernova and Query on Cosmic Dark Energy. Qiuhe Peng Yiming Hu Kun ... https://www.ias.ac.in/article/fulltext/joaa/035/03/0253-0256 ... Articles are also visible in Web of Science immediately. All these ...

  6. Error analysis of some Galerkin - least squares methods for the elasticity equations

    International Nuclear Information System (INIS)

    Franca, L.P.; Stenberg, R.

    1989-05-01

    We consider the recent technique of stabilizing mixed finite element methods by augmenting the Galerkin formulation with least squares terms calculated separately on each element. The error analysis is performed in a unified manner yielding improved results for some methods introduced earlier. In addition, a new formulation is introduced and analyzed [pt

  7. Time-series analysis of Nigeria rice supply and demand: Error ...

    African Journals Online (AJOL)

    The study examined a time-series analysis of Nigeria rice supply and demand with a view to determining any long-run equilibrium between them using the Error Correction Model approach (ECM). The data used for the study represents the annual series of 1960-2007 (47 years) for rice supply and demand in Nigeria, ...

  8. Advanced GIS Exercise: Performing Error Analysis in ArcGIS ModelBuilder

    Science.gov (United States)

    Hall, Steven T.; Post, Christopher J.

    2009-01-01

    Knowledge of Geographic Information Systems is quickly becoming an integral part of the natural resource professionals' skill set. With the growing need of professionals with these skills, we created an advanced geographic information systems (GIS) exercise for students at Clemson University to introduce them to the concept of error analysis,…

  9. Electric capacitance tomography and two-phase flow for the nuclear reactor safety analysis

    International Nuclear Information System (INIS)

    Lee, Jae Young

    2008-01-01

    Recently electric capacitance tomography has been developed to be used in the analysis of two-phase flow. Although its electric field is not focused as the hard ray tomography such as the X-ray or gamma ray, its convenience of easy access to the system and easy maintenance due to no requirement of radiation shielding benefits us in its application in the two-phase flow study, one of important area in the nuclear safety analysis. In the present paper, the practical technologies in the electric capacitance tomography are represented in both parts of hardware and software. In the software part, both forward problem and inverse problem are discussed and the method of regularization. In the hardware part, the brief discussion of the electronics circuits is made which provides femto farad resolution with a reasonable speed (150 frame/sec for 16 electrodes). Some representative ideal cases are studied to demonstrate its potential capability for the two-phase flow analysis. Also, some variations of the tomography such as axial tomography, and three dimensional tomography are discussed. It was found that the present ECT is expected to become a useful tool to understand the complicated three dimensional two-phase flow which may be an important feature to be equipped by the safety analysis codes. (author)

  10. Prevalence of technical errors and periapical lesions in a sample of endodontically treated teeth: a CBCT analysis.

    Science.gov (United States)

    Nascimento, Eduarda Helena Leandro; Gaêta-Araujo, Hugo; Andrade, Maria Fernanda Silva; Freitas, Deborah Queiroz

    2018-01-21

    The aims of this study are to identify the most frequent technical errors in endodontically treated teeth and to determine which root canals were most often associated with those errors, as well as to relate endodontic technical errors and the presence of coronal restorations with periapical status by means of cone-beam computed tomography images. Six hundred eighteen endodontically treated teeth (1146 root canals) were evaluated for the quality of their endodontic treatment and for the presence of coronal restorations and periapical lesions. Each root canal was classified according to dental groups, and the endodontic technical errors were recorded. Chi-square's test and descriptive analyses were performed. Six hundred eighty root canals (59.3%) had periapical lesions. Maxillary molars and anterior teeth showed higher prevalence of periapical lesions (p technical error in all root canals, except for the second mesiobuccal root canal of maxillary molars and the distobuccal root canal of mandibular molars, which were non-filled in 78.4 and 30% of the cases, respectively. There is a high prevalence of apical radiolucencies, which increased in the presence of poor coronal restorations, endodontic technical errors, and when both conditions were concomitant. Underfilling was the most frequent technical error, followed by non-homogeneous and non-filled canals. Evaluation of endodontic treatment quality that considers every single root canal aims on warning dental practitioners of the prevalence of technical errors that could be avoided with careful treatment planning and execution.

  11. Nondestructive analysis of urinary calculi using micro computed tomography

    Directory of Open Access Journals (Sweden)

    Lingeman James E

    2004-12-01

    Full Text Available Abstract Background Micro computed tomography (micro CT has been shown to provide exceptionally high quality imaging of the fine structural detail within urinary calculi. We tested the idea that micro CT might also be used to identify the mineral composition of urinary stones non-destructively. Methods Micro CT x-ray attenuation values were measured for mineral that was positively identified by infrared microspectroscopy (FT-IR. To do this, human urinary stones were sectioned with a diamond wire saw. The cut surface was explored by FT-IR and regions of pure mineral were evaluated by micro CT to correlate x-ray attenuation values with mineral content. Additionally, intact stones were imaged with micro CT to visualize internal morphology and map the distribution of specific mineral components in 3-D. Results Micro CT images taken just beneath the cut surface of urinary stones showed excellent resolution of structural detail that could be correlated with structure visible in the optical image mode of FT-IR. Regions of pure mineral were not difficult to find by FT-IR for most stones and such regions could be localized on micro CT images of the cut surface. This was not true, however, for two brushite stones tested; in these, brushite was closely intermixed with calcium oxalate. Micro CT x-ray attenuation values were collected for six minerals that could be found in regions that appeared to be pure, including uric acid (3515 – 4995 micro CT attenuation units, AU, struvite (7242 – 7969 AU, cystine (8619 – 9921 AU, calcium oxalate dihydrate (13815 – 15797 AU, calcium oxalate monohydrate (16297 – 18449 AU, and hydroxyapatite (21144 – 23121 AU. These AU values did not overlap. Analysis of intact stones showed excellent resolution of structural detail and could discriminate multiple mineral types within heterogeneous stones. Conclusions Micro CT gives excellent structural detail of urinary stones, and these results demonstrate the feasibility

  12. Error analysis of isotope dilution mass spectrometry method with internal standard

    International Nuclear Information System (INIS)

    Rizhinskii, M.W.; Vitinskii, M.Y.

    1989-02-01

    The computation algorithms of the normalized isotopic ratios and element concentration by isotope dilution mass spectrometry with internal standard are presented. A procedure based on the Monte-Carlo calculation is proposed for predicting the magnitude of the errors to be expected. The estimation of systematic and random errors is carried out in the case of the certification of uranium and plutonium reference materials as well as for the use of those reference materials in the analysis of irradiated nuclear fuels. 4 refs, 11 figs, 2 tabs

  13. Estimating the approximation error when fixing unessential factors in global sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sobol' , I.M. [Institute for Mathematical Modelling of the Russian Academy of Sciences, Moscow (Russian Federation); Tarantola, S. [Joint Research Centre of the European Commission, TP361, Institute of the Protection and Security of the Citizen, Via E. Fermi 1, 21020 Ispra (Italy)]. E-mail: stefano.tarantola@jrc.it; Gatelli, D. [Joint Research Centre of the European Commission, TP361, Institute of the Protection and Security of the Citizen, Via E. Fermi 1, 21020 Ispra (Italy)]. E-mail: debora.gatelli@jrc.it; Kucherenko, S.S. [Imperial College London (United Kingdom); Mauntz, W. [Department of Biochemical and Chemical Engineering, Dortmund University (Germany)

    2007-07-15

    One of the major settings of global sensitivity analysis is that of fixing non-influential factors, in order to reduce the dimensionality of a model. However, this is often done without knowing the magnitude of the approximation error being produced. This paper presents a new theorem for the estimation of the average approximation error generated when fixing a group of non-influential factors. A simple function where analytical solutions are available is used to illustrate the theorem. The numerical estimation of small sensitivity indices is discussed.

  14. A human error taxonomy and its application to an automatic method accident analysis

    International Nuclear Information System (INIS)

    Matthews, R.H.; Winter, P.W.

    1983-01-01

    Commentary is provided on the quantification aspects of human factors analysis in risk assessment. Methods for quantifying human error in a plant environment are discussed and their application to system quantification explored. Such a programme entails consideration of the data base and a taxonomy of factors contributing to human error. A multi-levelled approach to system quantification is proposed, each level being treated differently drawing on the advantages of different techniques within the fault/event tree framework. Management, as controller of organization, planning and procedure, is assigned a dominant role. (author)

  15. Human errors identification using the human factors analysis and classification system technique (HFACS

    Directory of Open Access Journals (Sweden)

    G. A. Shirali

    2013-12-01

    .Result: In this study, 158 reports of accident in Ahvaz steel industry were analyzed by HFACS technique. This analysis showed that most of the human errors were: in the first level was related to the skill-based errors, in the second to the physical environment, in the third level to the inadequate supervision and in the fourth level to the management of resources. .Conclusion: Studying and analyzing of past events using the HFACS technique can identify the major and root causes of accidents and can be effective on prevent repetitions of such mishaps. Also, it can be used as a basis for developing strategies to prevent future events in steel industries.

  16. Analysis of Statistical Methods and Errors in the Articles Published in the Korean Journal of Pain

    Science.gov (United States)

    Yim, Kyoung Hoon; Han, Kyoung Ah; Park, Soo Young

    2010-01-01

    Background Statistical analysis is essential in regard to obtaining objective reliability for medical research. However, medical researchers do not have enough statistical knowledge to properly analyze their study data. To help understand and potentially alleviate this problem, we have analyzed the statistical methods and errors of articles published in the Korean Journal of Pain (KJP), with the intention to improve the statistical quality of the journal. Methods All the articles, except case reports and editorials, published from 2004 to 2008 in the KJP were reviewed. The types of applied statistical methods and errors in the articles were evaluated. Results One hundred and thirty-nine original articles were reviewed. Inferential statistics and descriptive statistics were used in 119 papers and 20 papers, respectively. Only 20.9% of the papers were free from statistical errors. The most commonly adopted statistical method was the t-test (21.0%) followed by the chi-square test (15.9%). Errors of omission were encountered 101 times in 70 papers. Among the errors of omission, "no statistics used even though statistical methods were required" was the most common (40.6%). The errors of commission were encountered 165 times in 86 papers, among which "parametric inference for nonparametric data" was the most common (33.9%). Conclusions We found various types of statistical errors in the articles published in the KJP. This suggests that meticulous attention should be given not only in the applying statistical procedures but also in the reviewing process to improve the value of the article. PMID:20552071

  17. Analysis of strain error sources in micro-beam Laue diffraction

    International Nuclear Information System (INIS)

    Hofmann, Felix; Eve, Sophie; Belnoue, Jonathan; Micha, Jean-Sébastien; Korsunsky, Alexander M.

    2011-01-01

    Micro-beam Laue diffraction is an experimental method that allows the measurement of local lattice orientation and elastic strain within individual grains of engineering alloys, ceramics, and other polycrystalline materials. Unlike other analytical techniques, e.g. based on electron microscopy, it is not limited to surface characterisation or thin sections, but rather allows non-destructive measurements in the material bulk. This is of particular importance for in situ loading experiments where the mechanical response of a material volume (rather than just surface) is studied and it is vital that no perturbation/disturbance is introduced by the measurement technique. Whilst the technique allows lattice orientation to be determined to a high level of precision, accurate measurement of elastic strains and estimating the errors involved is a significant challenge. We propose a simulation-based approach to assess the elastic strain errors that arise from geometrical perturbations of the experimental setup. Using an empirical combination rule, the contributions of different geometrical uncertainties to the overall experimental strain error are estimated. This approach was applied to the micro-beam Laue diffraction setup at beamline BM32 at the European Synchrotron Radiation Facility (ESRF). Using a highly perfect germanium single crystal, the mechanical stability of the instrument was determined and hence the expected strain errors predicted. Comparison with the actual strain errors found in a silicon four-point beam bending test showed good agreement. The simulation-based error analysis approach makes it possible to understand the origins of the experimental strain errors and thus allows a directed improvement of the experimental geometry to maximise the benefit in terms of strain accuracy.

  18. A Human Error Analysis with Physiological Signals during Utilizing Digital Devices

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Hee; Oh, Yeon Ju; Shin, Kwang Hyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The introduction of advanced MCR is accompanied with lots of changes and different forms and features through the virtue of new digital technologies. There are various kinds of digital devices such as flat panel displays, touch screens, and so on. The characteristics of these digital devices give many chances to the interface management, and can be integrated into a compact single workstation in an advanced MCR so that workers can operate the plant with minimum burden during any operating condition. However, these devices may introduce new types of human errors, and thus we need a means to evaluate and prevent such error, especially those related to the digital devices. Human errors have been retrospectively assessed for accident reviews and quantitatively evaluated through HRA for PSA. However, the ergonomic verification and validation is an important process to defend all human error potential in the NPP design. HRA is a crucial part of a PSA, and helps in preparing a countermeasure for design by drawing potential human error items that affect the overall safety of NPPs. Various HRA techniques are available however: they reveal shortages of the HMI design in the digital era. - HRA techniques depend on PSFs: this means that the scope dealing with human factors is previously limited, and thus all attributes of new digital devices may not be considered in HRA. - The data used to HRA are not close to the evaluation items. So, human error analysis is not easy to apply to design by several individual experiments and cases. - The results of HRA are not statistically meaningful because accidents including human errors in NPPs are rare and have been estimated as having an extremely low probability

  19. Analysis of the orbit errors in the CERN accelerators using model simulation

    International Nuclear Information System (INIS)

    Lee, M.; Kleban, S.; Clearwater, S.

    1987-09-01

    This paper will describe the use of the PLUS program to find various types of machine and beam errors such as, quadrupole strength, dipole strength, beam position monitors (BPMs), energy profile, and beam launch. We refer to this procedure as the GOLD (Generic Orbit and Lattice Debugger) Method which is a general technique that can be applied to analysis of errors in storage rings and transport lines. One useful feature of the Method is that it analyzes segments of a machine at a time so that the application and efficiency is independent of the size of the overall machine. Because the techniques are the same for all the types of problems it solves, the user need learn only how to find one type of error in order to use the program

  20. On the BER and capacity analysis of MIMO MRC systems with channel estimation error

    KAUST Repository

    Yang, Liang

    2011-10-01

    In this paper, we investigate the effect of channel estimation error on the capacity and bit-error rate (BER) of a multiple-input multiple-output (MIMO) transmit maximal ratio transmission (MRT) and receive maximal ratio combining (MRC) systems over uncorrelated Rayleigh fading channels. We first derive the ergodic (average) capacity expressions for such systems when power adaptation is applied at the transmitter. The exact capacity expression for the uniform power allocation case is also presented. Furthermore, to investigate the diversity order of MIMO MRT-MRC scheme, we derive the BER performance under a uniform power allocation policy. We also present an asymptotic BER performance analysis for the MIMO MRT-MRC system with multiuser diversity. The numerical results are given to illustrate the sensitivity of the main performance to the channel estimation error and the tightness of the approximate cutoff value. © 2011 IEEE.

  1. Equilibrium arsenic adsorption onto metallic oxides : Isotherm models, error analysis and removal mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Simsek, Esra Bilgin [Yalova University, Yalova (Turkmenistan); Beker, Ulker [Yldz Technical University, Istanbul (Turkmenistan)

    2014-11-15

    Arsenic adsorption properties of mono- (Fe or Al) and binary (Fe-Al) metal oxides supported on natural zeolite were investigated at three levels of temperature (298, 318 and 338 K). All data obtained from equilibrium experiments were analyzed by Freundlich, Langmuir, Dubinin-Radushkevich, Sips, Toth and Redlich-Peterson isotherms, and error functions were used to predict the best fitting model. The error analysis demonstrated that the As(Ⅴ) adsorption processes were best described by the Dubinin-Raduskevich model with the lowest sum of normalized error values. According to results, the presence of iron and aluminum oxides in the zeolite network improved the As(Ⅴ) adsorption capacity of the raw zeolite (ZNa). The X-ray photoelectron spectroscopy (XPS) analyses of ZNa-Fe and ZNa-AlFe samples suggested that the redox reactions are the postulated mechanisms for the adsorption onto them while the adsorption process is followed by surface complexation reactions for ZNa-Al.

  2. Doctors' duty to disclose error: a deontological or Kantian ethical analysis.

    Science.gov (United States)

    Bernstein, Mark; Brown, Barry

    2004-05-01

    Medical (surgical) error is being talked about more openly and besides being the subject of retrospective reviews, is now the subject of prospective research. Disclosure of error has been a difficult issue because of fear of embarrassment for doctors in the eyes of their peers, and fear of punitive action by patients, consisting of medicolegal action and/or complaints to doctors' governing bodies. This paper examines physicians' and surgeons' duty to disclose error, from an ethical standpoint; specifically by applying the moral philosophical theory espoused by Immanuel Kant (ie. deontology). The purpose of this discourse is to apply moral philosophical analysis to a delicate but important issue which will be a matter all physicians and surgeons will have to confront, probably numerous times, in their professional careers.

  3. Error-correction coding and decoding bounds, codes, decoders, analysis and applications

    CERN Document Server

    Tomlinson, Martin; Ambroze, Marcel A; Ahmed, Mohammed; Jibril, Mubarak

    2017-01-01

    This book discusses both the theory and practical applications of self-correcting data, commonly known as error-correcting codes. The applications included demonstrate the importance of these codes in a wide range of everyday technologies, from smartphones to secure communications and transactions. Written in a readily understandable style, the book presents the authors’ twenty-five years of research organized into five parts: Part I is concerned with the theoretical performance attainable by using error correcting codes to achieve communications efficiency in digital communications systems. Part II explores the construction of error-correcting codes and explains the different families of codes and how they are designed. Techniques are described for producing the very best codes. Part III addresses the analysis of low-density parity-check (LDPC) codes, primarily to calculate their stopping sets and low-weight codeword spectrum which determines the performance of these codes. Part IV deals with decoders desi...

  4. PRA (probabilistic risk analysis) in the nuclear sector. Quantifying human error and human malice

    International Nuclear Information System (INIS)

    Heyes, A.G.

    1995-01-01

    Regardless of the regulatory style chosen ('command and control' or 'functional') a vital prerequisite for coherent safety regulations in the nuclear power industry is the ability to assess accident risk. In this paper we present a critical analysis of current techniques of probabilistic risk analysis applied in the industry, with particular regard to the problems of quantifying risks arising from, or exacerbated by, human risk and/or human error. (Author)

  5. Working group of experts on rare events in human error analysis and quantification

    International Nuclear Information System (INIS)

    Goodstein, L.P.

    1977-01-01

    In dealing with the reference problem of rare events in nuclear power plants, the group has concerned itself with the man-machine system and, in particular, with human error analysis and quantification. The Group was requested to review methods of human reliability prediction, to evaluate the extent to which such analyses can be formalized and to establish criteria to be met by task conditions and system design which would permit a systematic, formal analysis. Recommendations are given on the Fessenheim safety system

  6. BANK CAPITAL AND MACROECONOMIC SHOCKS: A PRINCIPAL COMPONENTS ANALYSIS AND VECTOR ERROR CORRECTION MODEL

    Directory of Open Access Journals (Sweden)

    Christian NZENGUE PEGNET

    2011-07-01

    Full Text Available The recent financial turmoil has clearly highlighted the potential role of financial factors on amplification of macroeconomic developments and stressed the importance of analyzing the relationship between banks’ balance sheets and economic activity. This paper assesses the impact of the bank capital channel in the transmission of schocks in Europe on the basis of bank's balance sheet data. The empirical analysis is carried out through a Principal Component Analysis and in a Vector Error Correction Model.

  7. Analysis of radiation fields in tomography on diffusion gaseous sound

    International Nuclear Information System (INIS)

    Bekman, I.N.

    1999-01-01

    Perspectives of application of equilibrium and stationary variants of diffusion tomography with radioactive gaseous sounds for spatial reconstruction of heterogeneous media in materials technology were considered. The basic attention were allocated to creation of simple algorithms of detection of sound accumulation on the background of monotonically varying concentration field. Algorithms of transformation of two-dimensional radiation field in three-dimensional distribution of radiation sources were suggested. The methods of analytical elongation of concentration field permitting separation of regional anomalies on the background of local ones and vice verse were discussed. It was shown that both equilibrium and stationary variants of diffusion tomography detect the heterogeneity of testing material, provide reduction of spatial distribution of elements of its structure and give an estimation of relative degree of defectiveness

  8. Model selection for marginal regression analysis of longitudinal data with missing observations and covariate measurement error.

    Science.gov (United States)

    Shen, Chung-Wei; Chen, Yi-Hau

    2015-10-01

    Missing observations and covariate measurement error commonly arise in longitudinal data. However, existing methods for model selection in marginal regression analysis of longitudinal data fail to address the potential bias resulting from these issues. To tackle this problem, we propose a new model selection criterion, the Generalized Longitudinal Information Criterion, which is based on an approximately unbiased estimator for the expected quadratic error of a considered marginal model accounting for both data missingness and covariate measurement error. The simulation results reveal that the proposed method performs quite well in the presence of missing data and covariate measurement error. On the contrary, the naive procedures without taking care of such complexity in data may perform quite poorly. The proposed method is applied to data from the Taiwan Longitudinal Study on Aging to assess the relationship of depression with health and social status in the elderly, accommodating measurement error in the covariate as well as missing observations. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Error Analysis Of Students Working About Word Problem Of Linear Program With NEA Procedure

    Science.gov (United States)

    Santoso, D. A.; Farid, A.; Ulum, B.

    2017-06-01

    Evaluation and assessment is an important part of learning. In evaluation process of learning, written test is still commonly used. However, the tests usually do not following-up by further evaluation. The process only up to grading stage not to evaluate the process and errors which done by students. Whereas if the student has a pattern error and process error, actions taken can be more focused on the fault and why is that happen. NEA procedure provides a way for educators to evaluate student progress more comprehensively. In this study, students’ mistakes in working on some word problem about linear programming have been analyzed. As a result, mistakes are often made students exist in the modeling phase (transformation) and process skills (process skill) with the overall percentage distribution respectively 20% and 15%. According to the observations, these errors occur most commonly due to lack of precision of students in modeling and in hastiness calculation. Error analysis with students on this matter, it is expected educators can determine or use the right way to solve it in the next lesson.

  10. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs in logarithmic received signal strength (RSS varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  11. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Science.gov (United States)

    Tian, Zengshan; Xu, Kunjie; Yu, Xiang

    2014-01-01

    This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs) in logarithmic received signal strength (RSS) varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs) as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future. PMID:24683349

  12. Discontinuous Galerkin methods and a posteriori error analysis for heterogenous diffusion problems

    International Nuclear Information System (INIS)

    Stephansen, A.F.

    2007-12-01

    In this thesis we analyse a discontinuous Galerkin (DG) method and two computable a posteriori error estimators for the linear and stationary advection-diffusion-reaction equation with heterogeneous diffusion. The DG method considered, the SWIP method, is a variation of the Symmetric Interior Penalty Galerkin method. The difference is that the SWIP method uses weighted averages with weights that depend on the diffusion. The a priori analysis shows optimal convergence with respect to mesh-size and robustness with respect to heterogeneous diffusion, which is confirmed by numerical tests. Both a posteriori error estimators are of the residual type and control the energy (semi-)norm of the error. Local lower bounds are obtained showing that almost all indicators are independent of heterogeneities. The exception is for the non-conforming part of the error, which has been evaluated using the Oswald interpolator. The second error estimator is sharper in its estimate with respect to the first one, but it is slightly more costly. This estimator is based on the construction of an H(div)-conforming Raviart-Thomas-Nedelec flux using the conservativeness of DG methods. Numerical results show that both estimators can be used for mesh-adaptation. (author)

  13. Covariate measurement error correction methods in mediation analysis with failure time data.

    Science.gov (United States)

    Zhao, Shanshan; Prentice, Ross L

    2014-12-01

    Mediation analysis is important for understanding the mechanisms whereby one variable causes changes in another. Measurement error could obscure the ability of the potential mediator to explain such changes. This article focuses on developing correction methods for measurement error in the mediator with failure time outcomes. We consider a broad definition of measurement error, including technical error, and error associated with temporal variation. The underlying model with the "true" mediator is assumed to be of the Cox proportional hazards model form. The induced hazard ratio for the observed mediator no longer has a simple form independent of the baseline hazard function, due to the conditioning event. We propose a mean-variance regression calibration approach and a follow-up time regression calibration approach, to approximate the partial likelihood for the induced hazard function. Both methods demonstrate value in assessing mediation effects in simulation studies. These methods are generalized to multiple biomarkers and to both case-cohort and nested case-control sampling designs. We apply these correction methods to the Women's Health Initiative hormone therapy trials to understand the mediation effect of several serum sex hormone measures on the relationship between postmenopausal hormone therapy and breast cancer risk. © 2014, The International Biometric Society.

  14. Error Analysis in a Device to Test Optical Systems by Using Ronchi Test and Phase Shifting

    International Nuclear Information System (INIS)

    Cabrera-Perez, Brasilia; Castro-Ramos, Jorge; Gordiano-Alvarado, Gabriel; Vazquez y Montiel, Sergio

    2008-01-01

    In optical workshops, Ronchi test is used to determine the optical quality of any concave surface, while it is in the polishing process its quality is verified. The Ronchi test is one of the simplest and most effective methods used for evaluating and measuring aberrations. In this work, we describe a device to test converging mirrors and lenses either with small F/numbers or large F/numbers, using LED (Light-Emitting Diode) that has been adapted in the Ronchi testing as source of illumination. With LED used the radiation angle is bigger than common LED. It uses external power supplies to have well stability intensity to avoid error during the phase shift. The setup also has the advantage to receive automatic input and output data, this is possible because phase shifting interferometry and a square Ronchi ruling with a variable intensity LED were used. Error analysis of the different parameters involved in the test of Ronchi was made. For example, we analyze the error in the shifting of phase, the error introduced by the movement of the motor, misalignments of x-axis, y-axis and z-axis of the surface under test, error in the period of the grid used

  15. Error Analysis of Deep Sequencing of Phage Libraries: Peptides Censored in Sequencing

    Directory of Open Access Journals (Sweden)

    Wadim L. Matochko

    2013-01-01

    Full Text Available Next-generation sequencing techniques empower selection of ligands from phage-display libraries because they can detect low abundant clones and quantify changes in the copy numbers of clones without excessive selection rounds. Identification of errors in deep sequencing data is the most critical step in this process because these techniques have error rates >1%. Mechanisms that yield errors in Illumina and other techniques have been proposed, but no reports to date describe error analysis in phage libraries. Our paper focuses on error analysis of 7-mer peptide libraries sequenced by Illumina method. Low theoretical complexity of this phage library, as compared to complexity of long genetic reads and genomes, allowed us to describe this library using convenient linear vector and operator framework. We describe a phage library as N×1 frequency vector n=ni, where ni is the copy number of the ith sequence and N is the theoretical diversity, that is, the total number of all possible sequences. Any manipulation to the library is an operator acting on n. Selection, amplification, or sequencing could be described as a product of a N×N matrix and a stochastic sampling operator (Sa. The latter is a random diagonal matrix that describes sampling of a library. In this paper, we focus on the properties of Sa and use them to define the sequencing operator (Seq. Sequencing without any bias and errors is Seq=Sa IN, where IN is a N×N unity matrix. Any bias in sequencing changes IN to a nonunity matrix. We identified a diagonal censorship matrix (CEN, which describes elimination or statistically significant downsampling, of specific reads during the sequencing process.

  16. Information Management System Development for the Investigation, Reporting, and Analysis of Human Error in Naval Aviation Maintenance

    National Research Council Canada - National Science Library

    Nelson, Douglas

    2001-01-01

    The purpose of this research is to evaluate and refine a safety information management system that will facilitate data collection, organization, query, analysis and reporting of maintenance errors...

  17. Information Management System Development for the Characterization and Analysis of Human Error in Naval Aviation Maintenance Related Mishaps

    National Research Council Canada - National Science Library

    Wood, Brian

    2000-01-01

    .... The Human Factors Analysis and Classification System-Maintenance Extension taxonomy, an effective framework for classifying and analyzing the presence of maintenance errors that lead to mishaps...

  18. On Gait Analysis Estimation Errors Using Force Sensors on a Smart Rollator.

    Science.gov (United States)

    Ballesteros, Joaquin; Urdiales, Cristina; Martinez, Antonio B; van Dieën, Jaap H

    2016-11-10

    Gait analysis can provide valuable information on a person's condition and rehabilitation progress. Gait is typically captured using external equipment and/or wearable sensors. These tests are largely constrained to specific controlled environments. In addition, gait analysis often requires experts for calibration, operation and/or to place sensors on volunteers. Alternatively, mobility support devices like rollators can be equipped with onboard sensors to monitor gait parameters, while users perform their Activities of Daily Living. Gait analysis in rollators may use odometry and force sensors in the handlebars. However, force based estimation of gait parameters is less accurate than traditional methods, especially when rollators are not properly used. This paper presents an evaluation of force based gait analysis using a smart rollator on different groups of users to determine when this methodology is applicable. In a second stage, the rollator is used in combination with two lab-based gait analysis systems to assess the rollator estimation error. Our results show that: (i) there is an inverse relation between the variance in the force difference between handlebars and support on the handlebars-related to the user condition-and the estimation error; and (ii) this error is lower than 10% when the variation in the force difference is above 7 N. This lower limit was exceeded by the 95.83% of our challenged volunteers. In conclusion, rollators are useful for gait characterization as long as users really need the device for ambulation.

  19. On Gait Analysis Estimation Errors Using Force Sensors on a Smart Rollator

    Directory of Open Access Journals (Sweden)

    Joaquin Ballesteros

    2016-11-01

    Full Text Available Gait analysis can provide valuable information on a person’s condition and rehabilitation progress. Gait is typically captured using external equipment and/or wearable sensors. These tests are largely constrained to specific controlled environments. In addition, gait analysis often requires experts for calibration, operation and/or to place sensors on volunteers. Alternatively, mobility support devices like rollators can be equipped with onboard sensors to monitor gait parameters, while users perform their Activities of Daily Living. Gait analysis in rollators may use odometry and force sensors in the handlebars. However, force based estimation of gait parameters is less accurate than traditional methods, especially when rollators are not properly used. This paper presents an evaluation of force based gait analysis using a smart rollator on different groups of users to determine when this methodology is applicable. In a second stage, the rollator is used in combination with two lab-based gait analysis systems to assess the rollator estimation error. Our results show that: (i there is an inverse relation between the variance in the force difference between handlebars and support on the handlebars—related to the user condition—and the estimation error; and (ii this error is lower than 10% when the variation in the force difference is above 7 N. This lower limit was exceeded by the 95.83% of our challenged volunteers. In conclusion, rollators are useful for gait characterization as long as users really need the device for ambulation.

  20. Republished error management: Descriptions of verbal communication errors between staff. An analysis of 84 root cause analysis-reports from Danish hospitals

    DEFF Research Database (Denmark)

    Rabøl, Louise Isager; Andersen, Mette Lehmann; Østergaard, Doris

    2011-01-01

    Introduction Poor teamwork and communication between healthcare staff are correlated to patient safety incidents. However, the organisational factors responsible for these issues are unexplored. Root cause analyses (RCA) use human factors thinking to analyse the systems behind severe patient safety...... and characteristics of verbal communication errors such as handover errors and error during teamwork. Results Raters found description of verbal communication errors in 44 reports (52%). These included handover errors (35 (86%)), communication errors between different staff groups (19 (43%)), misunderstandings (13...... (30%)), communication errors between junior and senior staff members (11 (25%)), hesitance in speaking up (10 (23%)) and communication errors during teamwork (8 (18%)). The kappa values were 0.44-0.78. Unproceduralized communication and information exchange via telephone, related to transfer between...

  1. Monte-Carlo error analysis in x-ray spectral deconvolution

    International Nuclear Information System (INIS)

    Shirk, D.G.; Hoffman, N.M.

    1985-01-01

    The deconvolution of spectral information from sparse x-ray data is a widely encountered problem in data analysis. An often-neglected aspect of this problem is the propagation of random error in the deconvolution process. We have developed a Monte-Carlo approach that enables us to attach error bars to unfolded x-ray spectra. Our Monte-Carlo error analysis has been incorporated into two specific deconvolution techniques: the first is an iterative convergent weight method; the second is a singular-value-decomposition (SVD) method. These two methods were applied to an x-ray spectral deconvolution problem having m channels of observations with n points in energy space. When m is less than n, this problem has no unique solution. We discuss the systematics of nonunique solutions and energy-dependent error bars for both methods. The Monte-Carlo approach has a particular benefit in relation to the SVD method: It allows us to apply the constraint of spectral nonnegativity after the SVD deconvolution rather than before. Consequently, we can identify inconsistencies between different detector channels

  2. Preanalytical errors in medical laboratories: a review of the available methodologies of data collection and analysis.

    Science.gov (United States)

    West, Jamie; Atherton, Jennifer; Costelloe, Seán J; Pourmahram, Ghazaleh; Stretton, Adam; Cornes, Michael

    2017-01-01

    Preanalytical errors have previously been shown to contribute a significant proportion of errors in laboratory processes and contribute to a number of patient safety risks. Accreditation against ISO 15189:2012 requires that laboratory Quality Management Systems consider the impact of preanalytical processes in areas such as the identification and control of non-conformances, continual improvement, internal audit and quality indicators. Previous studies have shown that there is a wide variation in the definition, repertoire and collection methods for preanalytical quality indicators. The International Federation of Clinical Chemistry Working Group on Laboratory Errors and Patient Safety has defined a number of quality indicators for the preanalytical stage, and the adoption of harmonized definitions will support interlaboratory comparisons and continual improvement. There are a variety of data collection methods, including audit, manual recording processes, incident reporting mechanisms and laboratory information systems. Quality management processes such as benchmarking, statistical process control, Pareto analysis and failure mode and effect analysis can be used to review data and should be incorporated into clinical governance mechanisms. In this paper, The Association for Clinical Biochemistry and Laboratory Medicine PreAnalytical Specialist Interest Group review the various data collection methods available. Our recommendation is the use of the laboratory information management systems as a recording mechanism for preanalytical errors as this provides the easiest and most standardized mechanism of data capture.

  3. Soft error rate analysis methodology of multi-Pulse-single-event transients

    International Nuclear Information System (INIS)

    Zhou Bin; Huo Mingxue; Xiao Liyi

    2012-01-01

    As transistor feature size scales down, soft errors in combinational logic because of high-energy particle radiation is gaining more and more concerns. In this paper, a combinational logic soft error analysis methodology considering multi-pulse-single-event transients (MPSETs) and re-convergence with multi transient pulses is proposed. In the proposed approach, the voltage pulse produced at the standard cell output is approximated by a triangle waveform, and characterized by three parameters: pulse width, the transition time of the first edge, and the transition time of the second edge. As for the pulse with the amplitude being smaller than the supply voltage, the edge extension technique is proposed. Moreover, an efficient electrical masking model comprehensively considering transition time, delay, width and amplitude is proposed, and an approach using the transition times of two edges and pulse width to compute the amplitude of pulse is proposed. Finally, our proposed firstly-independently-propagating-secondly-mutually-interacting (FIP-SMI) is used to deal with more practical re-convergence gate with multi transient pulses. As for MPSETs, a random generation model of MPSETs is exploratively proposed. Compared to the estimates obtained using circuit level simulations by HSpice, our proposed soft error rate analysis algorithm has 10% errors in SER estimation with speed up of 300 when the single-pulse-single-event transient (SPSET) is considered. We have also demonstrated the runtime and SER decrease with the increment of P0 using designs from the ISCAS-85 benchmarks. (authors)

  4. Systematic analysis of dependent human errors from the maintenance history at finnish NPPs - A status report

    Energy Technology Data Exchange (ETDEWEB)

    Laakso, K. [VTT Industrial Systems (Finland)

    2002-12-01

    Operating experience has shown missed detection events, where faults have passed inspections and functional tests to operating periods after the maintenance activities during the outage. The causes of these failures have often been complex event sequences, involving human and organisational factors. Especially common cause and other dependent failures of safety systems may significantly contribute to the reactor core damage risk. The topic has been addressed in the Finnish studies of human common cause failures, where experiences on latent human errors have been searched and analysed in detail from the maintenance history. The review of the bulk of the analysis results of the Olkiluoto and Loviisa plant sites shows that the instrumentation and control and electrical equipment is more prone to human error caused failure events than the other maintenance and that plant modifications and also predetermined preventive maintenance are significant sources of common cause failures. Most errors stem from the refuelling and maintenance outage period at the both sites, and less than half of the dependent errors were identified during the same outage. The dependent human errors originating from modifications could be reduced by a more tailored specification and coverage of their start-up testing programs. Improvements could also be achieved by a more case specific planning of the installation inspection and functional testing of complicated maintenance works or work objects of higher plant safety and availability importance. A better use and analysis of condition monitoring information for maintenance steering could also help. The feedback from discussions of the analysis results with plant experts and professionals is still crucial in developing the final conclusions and recommendations that meet the specific development needs at the plants. (au)

  5. Error analysis for determination of accuracy of an ultrasound navigation system for head and neck surgery.

    Science.gov (United States)

    Kozak, J; Krysztoforski, K; Kroll, T; Helbig, S; Helbig, M

    2009-01-01

    The use of conventional CT- or MRI-based navigation systems for head and neck surgery is unsatisfactory due to tissue shift. Moreover, changes occurring during surgical procedures cannot be visualized. To overcome these drawbacks, we developed a novel ultrasound-guided navigation system for head and neck surgery. A comprehensive error analysis was undertaken to determine the accuracy of this new system. The evaluation of the system accuracy was essentially based on the method of error definition for well-established fiducial marker registration methods (point-pair matching) as used in, for example, CT- or MRI-based navigation. This method was modified in accordance with the specific requirements of ultrasound-guided navigation. The Fiducial Localization Error (FLE), Fiducial Registration Error (FRE) and Target Registration Error (TRE) were determined. In our navigation system, the real error (the TRE actually measured) did not exceed a volume of 1.58 mm(3) with a probability of 0.9. A mean value of 0.8 mm (standard deviation: 0.25 mm) was found for the FRE. The quality of the coordinate tracking system (Polaris localizer) could be defined with an FLE of 0.4 +/- 0.11 mm (mean +/- standard deviation). The quality of the coordinates of the crosshairs of the phantom was determined with a deviation of 0.5 mm (standard deviation: 0.07 mm). The results demonstrate that our newly developed ultrasound-guided navigation system shows only very small system deviations and therefore provides very accurate data for practical applications.

  6. Chronology of prescribing error during the hospital stay and prediction of pharmacist's alerts overriding: a prospective analysis

    Directory of Open Access Journals (Sweden)

    Bruni Vanida

    2010-01-01

    Full Text Available Abstract Background Drug prescribing errors are frequent in the hospital setting and pharmacists play an important role in detection of these errors. The objectives of this study are (1 to describe the drug prescribing errors rate during the patient's stay, (2 to find which characteristics for a prescribing error are the most predictive of their reproduction the next day despite pharmacist's alert (i.e. override the alert. Methods We prospectively collected all medication order lines and prescribing errors during 18 days in 7 medical wards' using computerized physician order entry. We described and modelled the errors rate according to the chronology of hospital stay. We performed a classification and regression tree analysis to find which characteristics of alerts were predictive of their overriding (i.e. prescribing error repeated. Results 12 533 order lines were reviewed, 117 errors (errors rate 0.9% were observed and 51% of these errors occurred on the first day of the hospital stay. The risk of a prescribing error decreased over time. 52% of the alerts were overridden (i.e error uncorrected by prescribers on the following day. Drug omissions were the most frequently taken into account by prescribers. The classification and regression tree analysis showed that overriding pharmacist's alerts is first related to the ward of the prescriber and then to either Anatomical Therapeutic Chemical class of the drug or the type of error. Conclusions Since 51% of prescribing errors occurred on the first day of stay, pharmacist should concentrate his analysis of drug prescriptions on this day. The difference of overriding behavior between wards and according drug Anatomical Therapeutic Chemical class or type of error could also guide the validation tasks and programming of electronic alerts.

  7. The industrial computerized tomography applied to the rock analysis

    International Nuclear Information System (INIS)

    Tetzner, Guaraciaba de Campos

    2008-01-01

    This work is a study of the possibilities of the technical applications of Computerized Tomography (CT) by using a device developed in the Radiation Technology Center (CTR), Institute for Energy and Nuclear Research (IPEN-CNEN/SP). The equipment consists of a gamma radiation source ( 60 Co), a scintillation detector of sodium iodide doped with thallium (NaI (Tl)), a mechanical system to move the object (rotation and translation) and a computer system. This operating system has been designed and developed by the CTR-IPEN-CNEN/SP team using national resources and technology. The first validation test of the equipment was carried out using a cylindrical sample of polypropylene (phantom) with two cylindrical cavities (holes) of 5 x 25 cm (diameter and length). In these tests, the holes were filled with materials of different density (air, oil and metal), whose attenuation coefficients are well known. The goal of this first test was to assess the response quality of the equipment. The present report is a study comparing computerized tomography equipment CTR-IPEN-CNEN/SP which uses a source of gamma radiation ( 60 Co) and other equipment provided by the Department of Geosciences in the University of Texas (CTUT), which uses an X-ray source (450 kV and 3.2 mA). As a result, the images obtained and the comprehensive study of the usefulness of the equipment developed here strengthened the proposition that the development of industrial computerized tomography is an important step toward consolidating the national technology. (author)

  8. ATHEANA: A Technique for Human Error Analysis: An Overview of Its Methodological Basis

    International Nuclear Information System (INIS)

    Wreathall, John; Ramey-Smith, Ann

    1998-01-01

    The U.S. NRC has developed a new human reliability analysis (HRA) method, called A Technique for Human Event Analysis (ATHEANA), to provide a way of modeling the so-called 'errors of commission' - that is, situations in which operators terminate or disable engineered safety features (ESFs) or similar equipment during accident conditions, thereby putting the plant at an increased risk of core damage. In its reviews of operational events, NRC has found that these errors of commission occur with a relatively high frequency (as high as 2 or 3 per year), but are noticeably missing from the scope of most current probabilistic risk assessments (PRAs). This new method was developed through a formalized approach that describes what can occur when operators behave rationally but have inadequate knowledge or poor judgement. In particular, the method is based on models of decision-making and response planning that have been used extensively in the aviation field, and on the analysis of major accidents in both the nuclear and non-nuclear fields. Other papers at this conference present summaries of these event analyses in both the nuclear and non-nuclear fields. This paper presents an overview of ATHEANA and summarizes how the method structures the analysis of operationally significant events, and helps HRA analysts identify and model potentially risk-significant errors of commission in plant PRAs. (authors)

  9. Multi-scale analysis of lung computed tomography images

    CERN Document Server

    Gori, I; Fantacci, M E; Preite Martinez, A; Retico, A; De Mitri, I; Donadio, S; Fulcheri, C

    2007-01-01

    A computer-aided detection (CAD) system for the identification of lung internal nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 project. The three modules of our lung CAD system, a segmentation algorithm for lung internal region identification, a multi-scale dot-enhancement filter for nodule candidate selection and a multi-scale neural technique for false positive finding reduction, are described. The results obtained on a dataset of low-dose and thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

  10. Inclusive bit error rate analysis for coherent optical code-division multiple-access system

    Science.gov (United States)

    Katz, Gilad; Sadot, Dan

    2002-06-01

    Inclusive noise and bit error rate (BER) analysis for optical code-division multiplexing (OCDM) using coherence techniques is presented. The analysis contains crosstalk calculation of the mutual field variance for different number of users. It is shown that the crosstalk noise depends deeply on the receiver integration time, the laser coherence time, and the number of users. In addition, analytical results of the power fluctuation at the received channel due to the data modulation at the rejected channels are presented. The analysis also includes amplified spontaneous emission (ASE)-related noise effects of in-line amplifiers in a long-distance communication link.

  11. Mars gravity field error analysis from simulated radio tracking of Mars Observer

    International Nuclear Information System (INIS)

    Smith, D.E.; Lerch, F.J.; Chan, J.C.; Chinn, D.S.; Iz, H.B.; Mallama, A.; Patel, G.B.

    1990-01-01

    The Mars Observer (MO) Mission, in a near-polar orbit at 360-410 km altitude for nearly a 2-year observing period, will greatly improve our understanding of the geophysics of Mars, including its gravity field. To assess the expected improvement of the gravity field, the authors have conducted an error analysis based upon the mission plan for the Mars Observer radio tracking data from the Deep Space Network. Their results indicate that it should be possible to obtain a high-resolution model (spherical harmonics complete to degree and order 50 corresponding to a 200-km horizontal resolution) for the gravitational field of the planet. This model, in combination with topography from MO altimetry, should provide for an improved determination of the broad scale density structure and stress state of the Martian crust and upper mantle. The mathematical model for the error analysis is based on the representation of doppler tracking data as a function of the Martian gravity field in spherical harmonics, solar radiation pressure, atmospheric drag, angular momentum desaturation residual acceleration (AMDRA) effects, tracking station biases, and the MO orbit parameters. Two approaches are employed. In the first case, the error covariance matrix of the gravity model is estimated including the effects from all the nongravitational parameters (noise-only case). In the second case, the gravity recovery error is computed as above but includes unmodelled systematic effects from atmospheric drag, AMDRA, and solar radiation pressure (biased case). The error spectrum of gravity shows an order of magnitude of improvement over current knowledge based on doppler data precision from a single station of 0.3 mm s -1 noise for 1-min integration intervals during three 60-day periods

  12. Catching errors with patient-specific pretreatment machine log file analysis.

    Science.gov (United States)

    Rangaraj, Dharanipathy; Zhu, Mingyao; Yang, Deshan; Palaniswaamy, Geethpriya; Yaddanapudi, Sridhar; Wooten, Omar H; Brame, Scott; Mutic, Sasa

    2013-01-01

    A robust, efficient, and reliable quality assurance (QA) process is highly desired for modern external beam radiation therapy treatments. Here, we report the results of a semiautomatic, pretreatment, patient-specific QA process based on dynamic machine log file analysis clinically implemented for intensity modulated radiation therapy (IMRT) treatments delivered by high energy linear accelerators (Varian 2100/2300 EX, Trilogy, iX-D, Varian Medical Systems Inc, Palo Alto, CA). The multileaf collimator machine (MLC) log files are called Dynalog by Varian. Using an in-house developed computer program called "Dynalog QA," we automatically compare the beam delivery parameters in the log files that are generated during pretreatment point dose verification measurements, with the treatment plan to determine any discrepancies in IMRT deliveries. Fluence maps are constructed and compared between the delivered and planned beams. Since clinical introduction in June 2009, 912 machine log file analyses QA were performed by the end of 2010. Among these, 14 errors causing dosimetric deviation were detected and required further investigation and intervention. These errors were the result of human operating mistakes, flawed treatment planning, and data modification during plan file transfer. Minor errors were also reported in 174 other log file analyses, some of which stemmed from false positives and unreliable results; the origins of these are discussed herein. It has been demonstrated that the machine log file analysis is a robust, efficient, and reliable QA process capable of detecting errors originating from human mistakes, flawed planning, and data transfer problems. The possibility of detecting these errors is low using point and planar dosimetric measurements. Copyright © 2013 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  13. Measurements and their uncertainties a practical guide to modern error analysis

    CERN Document Server

    Hughes, Ifan G

    2010-01-01

    This hands-on guide is primarily intended to be used in undergraduate laboratories in the physical sciences and engineering. It assumes no prior knowledge of statistics. It introduces the necessary concepts where needed, with key points illustrated with worked examples and graphic illustrations. In contrast to traditional mathematical treatments it uses a combination of spreadsheet and calculus-based approaches, suitable as a quick and easy on-the-spot reference. The emphasisthroughout is on practical strategies to be adopted in the laboratory. Error analysis is introduced at a level accessible to school leavers, and carried through to research level. Error calculation and propagation is presented though a series of rules-of-thumb, look-up tables and approaches amenable to computer analysis. The general approach uses the chi-square statistic extensively. Particular attention is given to hypothesis testing and extraction of parameters and their uncertainties by fitting mathematical models to experimental data....

  14. Error tolerance analysis of wave diagnostic based on coherent modulation imaging in high power laser system

    Science.gov (United States)

    Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

    2018-02-01

    Coherent modulation imaging providing fast convergence speed and high resolution with single diffraction pattern is a promising technique to satisfy the urgent demands for on-line multiple parameter diagnostics with single setup in high power laser facilities (HPLF). However, the influence of noise on the final calculated parameters concerned has not been investigated yet. According to a series of simulations with twenty different sampling beams generated based on the practical parameters and performance of HPLF, the quantitative analysis based on statistical results was first investigated after considering five different error sources. We found the background noise of detector and high quantization error will seriously affect the final accuracy and different parameters have different sensitivity to different noise sources. The simulation results and the corresponding analysis provide the potential directions to further improve the final accuracy of parameter diagnostics which is critically important to its formal applications in the daily routines of HPLF.

  15. Application of human error theory in case analysis of wrong procedures.

    Science.gov (United States)

    Duthie, Elizabeth A

    2010-06-01

    The goal of this study was to contribute to the emerging body of literature about the role of human behaviors and cognitive processes in the commission of wrong procedures. Case analysis of 5 wrong procedures in operative and nonoperative settings using James Reason's human error theory was performed. The case analysis showed that cognitive underspecification, cognitive flips, automode processing, and skill-based errors were contributory to wrong procedures. Wrong-site procedures accounted for the preponderance of the cases. Front-line supervisory staff used corrective actions that focused on the performance of the individual without taking into account cognitive factors. System fixes using human cognition concepts have a greater chance of achieving sustainable safety outcomes than those that are based on the traditional approach of counseling, education, and disciplinary action for staff.

  16. Analysis of Human Errors in Japanese Nuclear Power Plants using JHPES/JAESS

    International Nuclear Information System (INIS)

    Kojima, Mitsuhiro; Mimura, Masahiro; Yamaguchi, Osamu

    1998-01-01

    CRIEPI (Central Research Institute for Electric Power Industries) / HFC (Human Factors research Center) developed J-HPES (Japanese version of Human Performance Enhancement System) based on the HPES which was originally developed by INPO to analyze events resulted from human errors. J-HPES was systematized into a computer program named JAESS (J-HPES Analysis and Evaluation Support System) and both systems were distributed to all Japanese electric power companies to analyze events by themselves. CRIEPI / HFC also analyzed the incidents in Japanese nuclear power plants (NPPs) which were officially reported and identified as human error related with J-HPES / JAESS. These incidents have numbered up to 188 cases over the last 30 years. An outline of this analysis is given, and some preliminary findings are shown. (authors)

  17. An Analysis of Ripple and Error Fields Induced by a Blanket in the CFETR

    Science.gov (United States)

    Yu, Guanying; Liu, Xufeng; Liu, Songlin

    2016-10-01

    The Chinese Fusion Engineering Tokamak Reactor (CFETR) is an important intermediate device between ITER and DEMO. The Water Cooled Ceramic Breeder (WCCB) blanket whose structural material is mainly made of Reduced Activation Ferritic/Martensitic (RAFM) steel, is one of the candidate conceptual blanket design. An analysis of ripple and error field induced by RAFM steel in WCCB is evaluated with the method of static magnetic analysis in the ANSYS code. Significant additional magnetic field is produced by blanket and it leads to an increased ripple field. Maximum ripple along the separatrix line reaches 0.53% which is higher than 0.5% of the acceptable design value. Simultaneously, one blanket module is taken out for heating purpose and the resulting error field is calculated to be seriously against the requirement. supported by National Natural Science Foundation of China (No. 11175207) and the National Magnetic Confinement Fusion Program of China (No. 2013GB108004)

  18. Quantitative analysis of cholesteatoma using high resolution computed tomography

    International Nuclear Information System (INIS)

    Kikuchi, Shigeru; Yamasoba, Tatsuya; Iinuma, Toshitaka.

    1992-01-01

    Seventy-three cases of adult cholesteatoma, including 52 cases of pars flaccida type cholesteatoma and 21 of pars tensa type cholesteatoma, were examined using high resolution computed tomography, in both axial (lateral semicircular canal plane) and coronal sections (cochlear, vestibular and antral plane). These cases were classified into two subtypes according to the presence of extension of cholesteatoma into the antrum. Sixty cases of chronic otitis media with central perforation (COM) were also examined as controls. Various locations of the middle ear cavity were measured in terms of size in comparison with pars flaccida type cholesteatoma, pars tensa type cholesteatoma and COM. The width of the attic was significantly larger in both pars flaccida type and pars tensa type cholesteatoma than in COM. With pars flaccida type cholesteatoma there was a significantly larger distance between the malleus and lateral wall of the attic than with COM. In contrast, the distance between the malleus and medial wall of the attic was significantly larger with pars tensa type cholesteatoma than with COM. With cholesteatoma extending into the antrum, regardless of the type of cholesteatoma, there were significantly larger distances than with COM at the following sites: the width and height of the aditus ad antrum, and the width, height and anterior-posterior diameter of the antrum. However, these distances were not significantly different between cholesteatoma without extension into the antrum and COM. The hitherto demonstrated qualitative impressions of bone destruction in cholesteatoma were quantitatively verified in detail using high resolution computed tomography. (author)

  19. Error Analysis and Calibration Method of a Multiple Field-of-View Navigation System

    OpenAIRE

    Shi, Shuai; Zhao, Kaichun; You, Zheng; Ouyang, Chenguang; Cao, Yongkui; Wang, Zhenzhou

    2017-01-01

    The Multiple Field-of-view Navigation System (MFNS) is a spacecraft subsystem built to realize the autonomous navigation of the Spacecraft Inside Tiangong Space Station. This paper introduces the basics of the MFNS, including its architecture, mathematical model and analysis, and numerical simulation of system errors. According to the performance requirement of the MFNS, the calibration of both intrinsic and extrinsic parameters of the system is assumed to be essential and pivotal. Hence, a n...

  20. Error Analysis of Explicit Partitioned Runge–Kutta Schemes for Conservation Laws

    KAUST Repository

    Hundsdorfer, Willem

    2014-08-27

    An error analysis is presented for explicit partitioned Runge–Kutta methods and multirate methods applied to conservation laws. The interfaces, across which different methods or time steps are used, lead to order reduction of the schemes. Along with cell-based decompositions, also flux-based decompositions are studied. In the latter case mass conservation is guaranteed, but it will be seen that the accuracy may deteriorate.

  1. Error analysis of the finite element and finite volume methods for some viscoelastic fluids

    Czech Academy of Sciences Publication Activity Database

    Lukáčová-Medviďová, M.; Mizerová, H.; She, B.; Stebel, Jan

    2016-01-01

    Roč. 24, č. 2 (2016), s. 105-123 ISSN 1570-2820 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : error analysis * Oldroyd-B type models * viscoelastic fluids Subject RIV: BA - General Mathematics Impact factor: 0.405, year: 2016 http://www.degruyter.com/view/j/jnma.2016.24.issue-2/jnma-2014-0057/jnma-2014-0057. xml

  2. Schur Complement Reduction in the Mixed-Hybrid Approximation of Darcy's Law: Rounding Error Analysis

    Czech Academy of Sciences Publication Activity Database

    Maryška, Jiří; Rozložník, Miroslav; Tůma, Miroslav

    2000-01-01

    Roč. 117, - (2000), s. 159-173 ISSN 0377-0427 R&D Projects: GA AV ČR IAA2030706; GA ČR GA201/98/P108 Institutional research plan: AV0Z1030915 Keywords : potential fluid flow problem * symmetric indefinite linear systems * Schur complement reduction * iterative methods * rounding error analysis Subject RIV: BA - General Mathematics Impact factor: 0.455, year: 2000

  3. Error Analysis of Explicit Partitioned Runge–Kutta Schemes for Conservation Laws

    KAUST Repository

    Hundsdorfer, Willem; Ketcheson, David I.; Savostianov, Igor

    2014-01-01

    An error analysis is presented for explicit partitioned Runge–Kutta methods and multirate methods applied to conservation laws. The interfaces, across which different methods or time steps are used, lead to order reduction of the schemes. Along with cell-based decompositions, also flux-based decompositions are studied. In the latter case mass conservation is guaranteed, but it will be seen that the accuracy may deteriorate.

  4. Proactive error analysis of ultrasound-guided axillary brachial plexus block performance.

    LENUS (Irish Health Repository)

    O'Sullivan, Owen

    2012-07-13

    Detailed description of the tasks anesthetists undertake during the performance of a complex procedure, such as ultrasound-guided peripheral nerve blockade, allows elements that are vulnerable to human error to be identified. We have applied 3 task analysis tools to one such procedure, namely, ultrasound-guided axillary brachial plexus blockade, with the intention that the results may form a basis to enhance training and performance of the procedure.

  5. A Posteriori Error Analysis and Uncertainty Quantification for Adaptive Multiscale Operator Decomposition Methods for Multiphysics Problems

    Science.gov (United States)

    2014-04-01

    Integral Role in Soft Tissue Mechanics, K. Troyer, D. Estep, and C. Puttlitz, Acta Biomaterialia 8 (201 2), 234-244 • A posteriori analysis of multi rate...2013, submitted • A posteriori error estimation for the Lax -Wendroff finite difference scheme, J. B. Collins, D. Estep, and S. Tavener, Journal of...oped over neArly six decades of activity and the major developments form a highly inter- connected web. We do not. ətternpt to review the history of

  6. A Conceptual Framework of Human Reliability Analysis for Execution Human Error in NPP Advanced MCRs

    International Nuclear Information System (INIS)

    Jang, In Seok; Kim, Ar Ryum; Seong, Poong Hyun; Jung, Won Dea

    2014-01-01

    The operation environment of Main Control Rooms (MCRs) in Nuclear Power Plants (NPPs) has changed with the adoption of new human-system interfaces that are based on computer-based technologies. The MCRs that include these digital and computer technologies, such as large display panels, computerized procedures, and soft controls, are called Advanced MCRs. Among the many features of Advanced MCRs, soft controls are a particularly important feature because the operation action in NPP Advanced MCRs is performed by soft control. Using soft controls such as mouse control, and touch screens, operators can select a specific screen, then choose the controller, and finally manipulate the given devices. Due to the different interfaces between soft control and hardwired conventional type control, different human error probabilities and a new Human Reliability Analysis (HRA) framework should be considered in the HRA for advanced MCRs. In other words, new human error modes should be considered for interface management tasks such as navigation tasks, and icon (device) selection tasks in monitors and a new framework of HRA method taking these newly generated human error modes into account should be considered. In this paper, a conceptual framework for a HRA method for the evaluation of soft control execution human error in advanced MCRs is suggested by analyzing soft control tasks

  7. A Conceptual Framework of Human Reliability Analysis for Execution Human Error in NPP Advanced MCRs

    Energy Technology Data Exchange (ETDEWEB)

    Jang, In Seok; Kim, Ar Ryum; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of); Jung, Won Dea [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-08-15

    The operation environment of Main Control Rooms (MCRs) in Nuclear Power Plants (NPPs) has changed with the adoption of new human-system interfaces that are based on computer-based technologies. The MCRs that include these digital and computer technologies, such as large display panels, computerized procedures, and soft controls, are called Advanced MCRs. Among the many features of Advanced MCRs, soft controls are a particularly important feature because the operation action in NPP Advanced MCRs is performed by soft control. Using soft controls such as mouse control, and touch screens, operators can select a specific screen, then choose the controller, and finally manipulate the given devices. Due to the different interfaces between soft control and hardwired conventional type control, different human error probabilities and a new Human Reliability Analysis (HRA) framework should be considered in the HRA for advanced MCRs. In other words, new human error modes should be considered for interface management tasks such as navigation tasks, and icon (device) selection tasks in monitors and a new framework of HRA method taking these newly generated human error modes into account should be considered. In this paper, a conceptual framework for a HRA method for the evaluation of soft control execution human error in advanced MCRs is suggested by analyzing soft control tasks.

  8. Morphometric analysis - Cone beam computed tomography to predict bone quality and quantity.

    Science.gov (United States)

    Hohlweg-Majert, B; Metzger, M C; Kummer, T; Schulze, D

    2011-07-01

    Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. MATERIALS AND PROCEDURES: Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality. 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  9. Evaluating the prevalence and impact of examiner errors on the Wechsler scales of intelligence: A meta-analysis.

    Science.gov (United States)

    Styck, Kara M; Walsh, Shana M

    2016-01-01

    The purpose of the present investigation was to conduct a meta-analysis of the literature on examiner errors for the Wechsler scales of intelligence. Results indicate that a mean of 99.7% of protocols contained at least 1 examiner error when studies that included a failure to record examinee responses as an error were combined and a mean of 41.2% of protocols contained at least 1 examiner error when studies that ignored errors of omission were combined. Furthermore, graduate student examiners were significantly more likely to make at least 1 error on Wechsler intelligence test protocols than psychologists. However, psychologists made significantly more errors per protocol than graduate student examiners regardless of the inclusion or exclusion of failure to record examinee responses as errors. On average, 73.1% of Full-Scale IQ (FSIQ) scores changed as a result of examiner errors, whereas 15.8%-77.3% of scores on the Verbal Comprehension Index (VCI), Perceptual Reasoning Index (PRI), Working Memory Index (WMI), and Processing Speed Index changed as a result of examiner errors. In addition, results suggest that examiners tend to overestimate FSIQ scores and underestimate VCI scores. However, no strong pattern emerged for the PRI and WMI. It can be concluded that examiner errors occur frequently and impact index and FSIQ scores. Consequently, current estimates for the standard error of measurement of popular IQ tests may not adequately capture the variance due to the examiner. (c) 2016 APA, all rights reserved).

  10. Analysis of the computed tomography in the acute abdomen; Analise da tomografia computadorizada no abdome agudo

    Energy Technology Data Exchange (ETDEWEB)

    Hochhegger, Bruno [Complexo Hospitalar Santa Casa de Porto Alegre, RS (Brazil); Moraes, Everton [Universidade Federal de Santa Maria (UFSM), RS (Brazil); Haygert, Carlos Jesus Pereira; Antunes, Paulo Sergio Pase [Hospital Universitario de Santa Maria, RS (Brazil); Gazzoni, Fernando [Pontificia Universidade Catolica de Porto Alegre (PUC-RS), Porto Alegre, RS (Brazil). Hospital Sao Lucas; Andrade, Rubens Gabriel Feijo [Fundacao Universitaria de Cardiologia de Porto Alegre, RS (Brazil). Inst. de Cardiologia; Bueno, Leticia Rossi [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil); Lopes, Luis Felipe Dias [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Estatistica]. E-mail: brunorgs@pop.com.br

    2007-07-01

    Introduction: This study tends to test the capacity of the computed tomography in assist in the diagnosis and the approach of the acute abdomen. Material and method: This is a longitudinal and prospective study, in which were analyzed the patients with the diagnosis of acute abdomen. There were obtained 105 cases of acute abdomen and after the application of the exclusions criteria were included 28 patients in the study. Results: Computed tomography changed the diagnostic hypothesis of the physicians in 50% of the cases (p < 0.05), and the confidence index in 85.71% of the cases (p 0.014). Computed tomography also altered the management in 46.43% of the cases (p > 0.05), where 78.57% of the patients had surgical indication before computed tomography and 67.86% after computed tomography (p = 0.0546). The index of accurate diagnosis of computed tomography, when compared to the anatomopathologic examination and the final diagnosis, was observed in 82.14% of the cases (p = 0.013). When the analysis was done dividing the patients in surgical and nonsurgical group, were obtained an accuracy of 89.28% (p 0.0001). The difference of 7.2 days of hospitalization (p = 0.003) was obtained compared with the mean of the acute abdomen without use the computed tomography. Conclusion: The computed tomography is correlative with the anatomopathology and has great accuracy in the surgical indication, associated with the capacity of increase the confident index of the physicians, reduces the hospitalization time, reduces the number of surgeries and is cost-effective. (author)

  11. Safety analysis methodology with assessment of the impact of the prediction errors of relevant parameters

    International Nuclear Information System (INIS)

    Galia, A.V.

    2011-01-01

    The best estimate plus uncertainty approach (BEAU) requires the use of extensive resources and therefore it is usually applied for cases in which the available safety margin obtained with a conservative methodology can be questioned. Outside the BEAU methodology, there is not a clear approach on how to deal with the issue of considering the uncertainties resulting from prediction errors in the safety analyses performed for licensing submissions. However, the regulatory document RD-310 mentions that the analysis method shall account for uncertainties in the analysis data and models. A possible approach is presented, that is simple and reasonable, representing just the author's views, to take into account the impact of prediction errors and other uncertainties when performing safety analysis in line with regulatory requirements. The approach proposes taking into account the prediction error of relevant parameters. Relevant parameters would be those plant parameters that are surveyed and are used to initiate the action of a mitigating system or those that are representative of the most challenging phenomena for the integrity of a fission barrier. Examples of the application of the methodology are presented involving a comparison between the results with the new approach and a best estimate calculation during the blowdown phase for two small breaks in a generic CANDU 6 station. The calculations are performed with the CATHENA computer code. (author)

  12. A Monte Carlo error simulation applied to calibration-free X-ray diffraction phase analysis

    International Nuclear Information System (INIS)

    Braun, G.E.

    1986-01-01

    Quantitative phase analysis of a system of n phases can be effected without the need for calibration standards provided at least n different mixtures of these phases are available. A series of linear equations relating diffracted X-ray intensities, weight fractions and quantitation factors coupled with mass balance relationships can be solved for the unknown weight fractions and factors. Uncertainties associated with the measured X-ray intensities, owing to counting of random X-ray quanta, are used to estimate the errors in the calculated parameters utilizing a Monte Carlo simulation. The Monte Carlo approach can be generalized and applied to any quantitative X-ray diffraction phase analysis method. Two examples utilizing mixtures of CaCO 3 , Fe 2 O 3 and CaF 2 with an α-SiO 2 (quartz) internal standard illustrate the quantitative method and corresponding error analysis. One example is well conditioned; the other is poorly conditioned and, therefore, very sensitive to errors in the measured intensities. (orig.)

  13. Trend analysis of human error events and assessment of their proactive prevention measure at Rokkasho reprocessing plant

    International Nuclear Information System (INIS)

    Yamazaki, Satoru; Tanaka, Izumi; Wakabayashi, Toshio

    2012-01-01

    A trend analysis of human error events is important for preventing the recurrence of human error events. We propose a new method for identifying the common characteristics from results of trend analysis, such as the latent weakness of organization, and a management process for strategic error prevention. In this paper, we describe a trend analysis method for human error events that have been accumulated in the organization and the utilization of the results of trend analysis to prevent accidents proactively. Although the systematic analysis of human error events, the monitoring of their overall trend, and the utilization of the analyzed results have been examined for the plant operation, such information has never been utilized completely. Sharing information on human error events and analyzing their causes lead to the clarification of problems in the management and human factors. This new method was applied to the human error events that occurred in the Rokkasho reprocessing plant from 2010 October. Results revealed that the output of this method is effective in judging the error prevention plan and that the number of human error events is reduced to about 50% those observed in 2009 and 2010. (author)

  14. A trend analysis of human error events for proactive prevention of accidents. Methodology development and effective utilization

    International Nuclear Information System (INIS)

    Hirotsu, Yuko; Ebisu, Mitsuhiro; Aikawa, Takeshi; Matsubara, Katsuyuki

    2006-01-01

    This paper described methods for analyzing human error events that has been accumulated in the individual plant and for utilizing the result to prevent accidents proactively. Firstly, a categorization framework of trigger action and causal factors of human error events were reexamined, and the procedure to analyze human error events was reviewed based on the framework. Secondly, a method for identifying the common characteristics of trigger action data and of causal factor data accumulated by analyzing human error events was clarified. In addition, to utilize the results of trend analysis effectively, methods to develop teaching material for safety education, to develop the checkpoints for the error prevention and to introduce an error management process for strategic error prevention were proposed. (author)

  15. A Preliminary ZEUS Lightning Location Error Analysis Using a Modified Retrieval Theory

    Science.gov (United States)

    Elander, Valjean; Koshak, William; Phanord, Dieudonne

    2004-01-01

    The ZEUS long-range VLF arrival time difference lightning detection network now covers both Europe and Africa, and there are plans for further expansion into the western hemisphere. In order to fully optimize and assess ZEUS lightning location retrieval errors and to determine the best placement of future receivers expected to be added to the network, a software package is being developed jointly between the NASA Marshall Space Flight Center (MSFC) and the University of Nevada Las Vegas (UNLV). The software package, called the ZEUS Error Analysis for Lightning (ZEAL), will be used to obtain global scale lightning location retrieval error maps using both a Monte Carlo approach and chi-squared curvature matrix theory. At the core of ZEAL will be an implementation of an Iterative Oblate (IO) lightning location retrieval method recently developed at MSFC. The IO method will be appropriately modified to account for variable wave propagation speed, and the new retrieval results will be compared with the current ZEUS retrieval algorithm to assess potential improvements. In this preliminary ZEAL work effort, we defined 5000 source locations evenly distributed across the Earth. We then used the existing (as well as potential future ZEUS sites) to simulate arrival time data between source and ZEUS site. A total of 100 sources were considered at each of the 5000 locations, and timing errors were selected from a normal distribution having a mean of 0 seconds and a standard deviation of 20 microseconds. This simulated "noisy" dataset was analyzed using the IO algorithm to estimate source locations. The exact locations were compared with the retrieved locations, and the results are summarized via several color-coded "error maps."

  16. An analysis of regional cerebral blood flow in impulsive murderers using single photon emission computed tomography.

    Science.gov (United States)

    Amen, Daniel G; Hanks, Chris; Prunella, Jill R; Green, Aisa

    2007-01-01

    The authors explored differences in regional cerebral blood flow in 11 impulsive murderers and 11 healthy comparison subjects using single photon emission computed tomography. The authors assessed subjects at rest and during a computerized go/no-go concentration task. Using statistical parametric mapping software, the authors performed voxel-by-voxel t tests to assess significant differences, making family-wide error corrections for multiple comparisons. Murderers were found to have significantly lower relative rCBF during concentration, particularly in areas associated with concentration and impulse control. These results indicate that nonemotionally laden stimuli may result in frontotemporal dysregulation in people predisposed to impulsive violence.

  17. Analysis of S-box in Image Encryption Using Root Mean Square Error Method

    Science.gov (United States)

    Hussain, Iqtadar; Shah, Tariq; Gondal, Muhammad Asif; Mahmood, Hasan

    2012-07-01

    The use of substitution boxes (S-boxes) in encryption applications has proven to be an effective nonlinear component in creating confusion and randomness. The S-box is evolving and many variants appear in literature, which include advanced encryption standard (AES) S-box, affine power affine (APA) S-box, Skipjack S-box, Gray S-box, Lui J S-box, residue prime number S-box, Xyi S-box, and S8 S-box. These S-boxes have algebraic and statistical properties which distinguish them from each other in terms of encryption strength. In some circumstances, the parameters from algebraic and statistical analysis yield results which do not provide clear evidence in distinguishing an S-box for an application to a particular set of data. In image encryption applications, the use of S-boxes needs special care because the visual analysis and perception of a viewer can sometimes identify artifacts embedded in the image. In addition to existing algebraic and statistical analysis already used for image encryption applications, we propose an application of root mean square error technique, which further elaborates the results and enables the analyst to vividly distinguish between the performances of various S-boxes. While the use of the root mean square error analysis in statistics has proven to be effective in determining the difference in original data and the processed data, its use in image encryption has shown promising results in estimating the strength of the encryption method. In this paper, we show the application of the root mean square error analysis to S-box image encryption. The parameters from this analysis are used in determining the strength of S-boxes

  18. Analysis of ring enhancement in the cranial computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seung Jae; Chung, Yong In; Chang, Kee Hyun [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1980-12-15

    A total of 83 cases with ring enhancement in the cranial computed tomography were radiologically analyzed to determine the specific CT findings of the primary and metastatic brain tumor, inflammatory disease, resolving hematoma, and cerebral infarction. The brief results are as follows. Glioblastoma multiform show a characteristic thick or thin irregular ring enhancement with significant mass effect and surrounding edema. Most of the metastatic tumors also show irregular thick or thin walled ring enhancement with significant surrounding edema. Tumoral hemorrhage was observed in the metastatic melanoma, breast cancer, and lung cancer. The brain abscess usually show characteristic thin regular and smooth ring enhancement with moderate peripheral edema. The parasitic cysts also show thin regular ring enhancement with different degree of surrounding edema. Ring enhancement in resolving hematomas and cerebral infarctions usually occurs about 10-30 days after the onset of symptoms, which shows thin and regular ring pattern without significant surrounding edema.

  19. Analysis of ring enhancement in the cranial computed tomography

    International Nuclear Information System (INIS)

    Huh, Seung Jae; Chung, Yong In; Chang, Kee Hyun

    1980-01-01

    A total of 83 cases with ring enhancement in the cranial computed tomography were radiologically analyzed to determine the specific CT findings of the primary and metastatic brain tumor, inflammatory disease, resolving hematoma, and cerebral infarction. The brief results are as follows. Glioblastoma multiform show a characteristic thick or thin irregular ring enhancement with significant mass effect and surrounding edema. Most of the metastatic tumors also show irregular thick or thin walled ring enhancement with significant surrounding edema. Tumoral hemorrhage was observed in the metastatic melanoma, breast cancer, and lung cancer. The brain abscess usually show characteristic thin regular and smooth ring enhancement with moderate peripheral edema. The parasitic cysts also show thin regular ring enhancement with different degree of surrounding edema. Ring enhancement in resolving hematomas and cerebral infarctions usually occurs about 10-30 days after the onset of symptoms, which shows thin and regular ring pattern without significant surrounding edema

  20. Analysis of dental abfractions by optical coherence tomography

    Science.gov (United States)

    Demjan, Enikö; Mărcăuţeanu, Corina; Bratu, Dorin; Sinescu, Cosmin; Negruţiu, Meda; Ionita, Ciprian; Topală, Florin; Hughes, Michael; Bradu, Adrian; Dobre, George; Podoleanu, Adrian Gh.

    2010-02-01

    Aim and objectives. Abfraction is the pathological loss of cervical hard tooth substance caused by biomechanical overload. High horizontal occlusal forces result in large stress concentrations in the cervical region of the teeth. These stresses may be high enough to cause microfractures in the dental hard tissues, eventually resulting in the loss of cervical enamel and dentin. The present study proposes the microstructural characterization of these cervical lesions by en face optical coherence tomography (eFOCT). Material and methods: 31 extracted bicuspids were investigated using eFOCT. 24 teeth derived from patients with active bruxism and occlusal interferences; they presented deep buccal abfractions and variable degrees of occlusal pathological attrition. The other 7 bicuspids were not exposed to occlusal overload and had a normal morphology of the dental crowns. The dental samples were investigated using an eFOCT system operating at 1300 nm (B-scan at 1 Hz and C-scan mode at 2 Hz). The system has a lateral resolution better than 5 μm and a depth resolution of 9 μm in tissue. OCT images were further compared with micro - computer tomography images. Results. The eFOCT investigation of bicuspids with a normal morphology revealed a homogeneous structure of the buccal cervical enamel. The C-scan and B-scan images obtained from the occlusal overloaded bicuspids visualized the wedge-shaped loss of cervical enamel and damage in the microstructure of the underlaying dentin. The high occlusal forces produced a characteristic pattern of large cracks, which reached the tooth surface. Conclusions: eFOCT is a promising imaging method for dental abfractions and it may offer some insight on the etiological mechanism of these noncarious cervical lesions.

  1. Three-dimensional structural analysis of eukaryotic flagella/cilia by electron cryo-tomography

    International Nuclear Information System (INIS)

    Bui, Khanh Huy; Pigino, Gaia; Ishikawa, Takashi

    2011-01-01

    Based on the molecular architecture revealed by electron cryo-tomography, the mechanism of the bending motion of eukaryotic flagella/cilia is discussed. Electron cryo-tomography is a potential approach to analyzing the three-dimensional conformation of frozen hydrated biological macromolecules using electron microscopy. Since projections of each individual object illuminated from different orientations are merged, electron tomography is capable of structural analysis of such heterogeneous environments as in vivo or with polymorphism, although radiation damage and the missing wedge are severe problems. Here, recent results on the structure of eukaryotic flagella, which is an ATP-driven bending organelle, from green algae Chlamydomonas are presented. Tomographic analysis reveals asymmetric molecular arrangements, especially that of the dynein motor proteins, in flagella, giving insight into the mechanism of planar asymmetric bending motion. Methodological challenges to obtaining higher-resolution structures from this technique are also discussed

  2. Error analysis of filtering operations in pixel-duplicated images of diabetic retinopathy

    Science.gov (United States)

    Mehrubeoglu, Mehrube; McLauchlan, Lifford

    2010-08-01

    In this paper, diabetic retinopathy is chosen for a sample target image to demonstrate the effectiveness of image enlargement through pixel duplication in identifying regions of interest. Pixel duplication is presented as a simpler alternative to data interpolation techniques for detecting small structures in the images. A comparative analysis is performed on different image processing schemes applied to both original and pixel-duplicated images. Structures of interest are detected and and classification parameters optimized for minimum false positive detection in the original and enlarged retinal pictures. The error analysis demonstrates the advantages as well as shortcomings of pixel duplication in image enhancement when spatial averaging operations (smoothing filters) are also applied.

  3. BEATBOX v1.0: Background Error Analysis Testbed with Box Models

    Science.gov (United States)

    Knote, Christoph; Barré, Jérôme; Eckl, Max

    2018-02-01

    The Background Error Analysis Testbed (BEATBOX) is a new data assimilation framework for box models. Based on the BOX Model eXtension (BOXMOX) to the Kinetic Pre-Processor (KPP), this framework allows users to conduct performance evaluations of data assimilation experiments, sensitivity analyses, and detailed chemical scheme diagnostics from an observation simulation system experiment (OSSE) point of view. The BEATBOX framework incorporates an observation simulator and a data assimilation system with the possibility of choosing ensemble, adjoint, or combined sensitivities. A user-friendly, Python-based interface allows for the tuning of many parameters for atmospheric chemistry and data assimilation research as well as for educational purposes, for example observation error, model covariances, ensemble size, perturbation distribution in the initial conditions, and so on. In this work, the testbed is described and two case studies are presented to illustrate the design of a typical OSSE experiment, data assimilation experiments, a sensitivity analysis, and a method for diagnosing model errors. BEATBOX is released as an open source tool for the atmospheric chemistry and data assimilation communities.

  4. BEATBOX v1.0: Background Error Analysis Testbed with Box Models

    Directory of Open Access Journals (Sweden)

    C. Knote

    2018-02-01

    Full Text Available The Background Error Analysis Testbed (BEATBOX is a new data assimilation framework for box models. Based on the BOX Model eXtension (BOXMOX to the Kinetic Pre-Processor (KPP, this framework allows users to conduct performance evaluations of data assimilation experiments, sensitivity analyses, and detailed chemical scheme diagnostics from an observation simulation system experiment (OSSE point of view. The BEATBOX framework incorporates an observation simulator and a data assimilation system with the possibility of choosing ensemble, adjoint, or combined sensitivities. A user-friendly, Python-based interface allows for the tuning of many parameters for atmospheric chemistry and data assimilation research as well as for educational purposes, for example observation error, model covariances, ensemble size, perturbation distribution in the initial conditions, and so on. In this work, the testbed is described and two case studies are presented to illustrate the design of a typical OSSE experiment, data assimilation experiments, a sensitivity analysis, and a method for diagnosing model errors. BEATBOX is released as an open source tool for the atmospheric chemistry and data assimilation communities.

  5. Timing analysis for embedded systems using non-preemptive EDF scheduling under bounded error arrivals

    Directory of Open Access Journals (Sweden)

    Michael Short

    2017-07-01

    Full Text Available Embedded systems consist of one or more processing units which are completely encapsulated by the devices under their control, and they often have stringent timing constraints associated with their functional specification. Previous research has considered the performance of different types of task scheduling algorithm and developed associated timing analysis techniques for such systems. Although preemptive scheduling techniques have traditionally been favored, rapid increases in processor speeds combined with improved insights into the behavior of non-preemptive scheduling techniques have seen an increased interest in their use for real-time applications such as multimedia, automation and control. However when non-preemptive scheduling techniques are employed there is a potential lack of error confinement should any timing errors occur in individual software tasks. In this paper, the focus is upon adding fault tolerance in systems using non-preemptive deadline-driven scheduling. Schedulability conditions are derived for fault-tolerant periodic and sporadic task sets experiencing bounded error arrivals under non-preemptive deadline scheduling. A timing analysis algorithm is presented based upon these conditions and its run-time properties are studied. Computational experiments show it to be highly efficient in terms of run-time complexity and competitive ratio when compared to previous approaches.

  6. Error analysis of satellite attitude determination using a vision-based approach

    Science.gov (United States)

    Carozza, Ludovico; Bevilacqua, Alessandro

    2013-09-01

    Improvements in communication and processing technologies have opened the doors to exploit on-board cameras to compute objects' spatial attitude using only the visual information from sequences of remote sensed images. The strategies and the algorithmic approach used to extract such information affect the estimation accuracy of the three-axis orientation of the object. This work presents a method for analyzing the most relevant error sources, including numerical ones, possible drift effects and their influence on the overall accuracy, referring to vision-based approaches. The method in particular focuses on the analysis of the image registration algorithm, carried out through on-purpose simulations. The overall accuracy has been assessed on a challenging case study, for which accuracy represents the fundamental requirement. In particular, attitude determination has been analyzed for small satellites, by comparing theoretical findings to metric results from simulations on realistic ground-truth data. Significant laboratory experiments, using a numerical control unit, have further confirmed the outcome. We believe that our analysis approach, as well as our findings in terms of error characterization, can be useful at proof-of-concept design and planning levels, since they emphasize the main sources of error for visual based approaches employed for satellite attitude estimation. Nevertheless, the approach we present is also of general interest for all the affine applicative domains which require an accurate estimation of three-dimensional orientation parameters (i.e., robotics, airborne stabilization).

  7. Suppressing carrier removal error in the Fourier transform method for interferogram analysis

    International Nuclear Information System (INIS)

    Fan, Qi; Yang, Hongru; Li, Gaoping; Zhao, Jianlin

    2010-01-01

    A new carrier removal method for interferogram analysis using the Fourier transform is presented. The proposed method can be used to suppress the carrier removal error as well as the spectral leakage error. First, the carrier frequencies are estimated with the spectral centroid of the up sidelobe of the apodized interferogram, and then the up sidelobe can be shifted to the origin in the frequency domain by multiplying the original interferogram by a constructed plane reference wave. The influence of the carrier frequencies without an integer multiple of the frequency interval and the window function for apodization of the interferogram can be avoided in our work. The simulation and experimental results show that this method is effective for phase measurement with a high accuracy from a single interferogram

  8. Residents' surgical performance during the laboratory years: an analysis of rule-based errors.

    Science.gov (United States)

    Nathwani, Jay N; Wise, Brett J; Garren, Margaret E; Mohamadipanah, Hossein; Van Beek, Nicole; DiMarco, Shannon M; Pugh, Carla M

    2017-11-01

    Nearly one-third of surgical residents will enter into academic development during their surgical residency by dedicating time to a research fellowship for 1-3 y. Major interest lies in understanding how laboratory residents' surgical skills are affected by minimal clinical exposure during academic development. A widely held concern is that the time away from clinical exposure results in surgical skills decay. This study examines the impact of the academic development years on residents' operative performance. We hypothesize that the use of repeated, annual assessments may result in learning even without individual feedback on participants simulated performance. Surgical performance data were collected from laboratory residents (postgraduate years 2-5) during the summers of 2014, 2015, and 2016. Residents had 15 min to complete a shortened, simulated laparoscopic ventral hernia repair procedure. Final hernia repair skins from all participants were scored using a previously validated checklist. An analysis of variance test compared the mean performance scores of repeat participants to those of first time participants. Twenty-seven (37% female) laboratory residents provided 2-year assessment data over the 3-year span of the study. Second time performance revealed improvement from a mean score of 14 (standard error = 1.0) in the first year to 17.2 (SD = 0.9) in the second year, (F[1, 52] = 5.6, P = 0.022). Detailed analysis demonstrated improvement in performance for 3 grading criteria that were considered to be rule-based errors. There was no improvement in operative strategy errors. Analysis of longitudinal performance of laboratory residents shows higher scores for repeat participants in the category of rule-based errors. These findings suggest that laboratory residents can learn from rule-based mistakes when provided with annual performance-based assessments. This benefit was not seen with operative strategy errors and has important implications for

  9. High‐resolution trench photomosaics from image‐based modeling: Workflow and error analysis

    Science.gov (United States)

    Reitman, Nadine G.; Bennett, Scott E. K.; Gold, Ryan D.; Briggs, Richard; Duross, Christopher

    2015-01-01

    Photomosaics are commonly used to construct maps of paleoseismic trench exposures, but the conventional process of manually using image‐editing software is time consuming and produces undesirable artifacts and distortions. Herein, we document and evaluate the application of image‐based modeling (IBM) for creating photomosaics and 3D models of paleoseismic trench exposures, illustrated with a case‐study trench across the Wasatch fault in Alpine, Utah. Our results include a structure‐from‐motion workflow for the semiautomated creation of seamless, high‐resolution photomosaics designed for rapid implementation in a field setting. Compared with conventional manual methods, the IBM photomosaic method provides a more accurate, continuous, and detailed record of paleoseismic trench exposures in approximately half the processing time and 15%–20% of the user input time. Our error analysis quantifies the effect of the number and spatial distribution of control points on model accuracy. For this case study, an ∼87  m2 exposure of a benched trench photographed at viewing distances of 1.5–7 m yields a model with <2  cm root mean square error (rmse) with as few as six control points. Rmse decreases as more control points are implemented, but the gains in accuracy are minimal beyond 12 control points. Spreading control points throughout the target area helps to minimize error. We propose that 3D digital models and corresponding photomosaics should be standard practice in paleoseismic exposure archiving. The error analysis serves as a guide for future investigations that seek balance between speed and accuracy during photomosaic and 3D model construction.

  10. Systematic Analysis of Video Data from Different Human-Robot Interaction Studies: A Categorisation of Social Signals During Error Situations

    OpenAIRE

    Manuel eGiuliani; Nicole eMirnig; Gerald eStollnberger; Susanne eStadler; Roland eBuchner; Manfred eTscheligi

    2015-01-01

    Human?robot interactions are often affected by error situations that are caused by either the robot or the human. Therefore, robots would profit from the ability to recognize when error situations occur. We investigated the verbal and non-verbal social signals that humans show when error situations occur in human?robot interaction experiments. For that, we analyzed 201 videos of five human?robot interaction user studies with varying tasks from four independent projects. The analysis shows tha...

  11. Technology-related medication errors in a tertiary hospital: a 5-year analysis of reported medication incidents.

    Science.gov (United States)

    Samaranayake, N R; Cheung, S T D; Chui, W C M; Cheung, B M Y

    2012-12-01

    Healthcare technology is meant to reduce medication errors. The objective of this study was to assess unintended errors related to technologies in the medication use process. Medication incidents reported from 2006 to 2010 in a main tertiary care hospital were analysed by a pharmacist and technology-related errors were identified. Technology-related errors were further classified as socio-technical errors and device errors. This analysis was conducted using data from medication incident reports which may represent only a small proportion of medication errors that actually takes place in a hospital. Hence, interpretation of results must be tentative. 1538 medication incidents were reported. 17.1% of all incidents were technology-related, of which only 1.9% were device errors, whereas most were socio-technical errors (98.1%). Of these, 61.2% were linked to computerised prescription order entry, 23.2% to bar-coded patient identification labels, 7.2% to infusion pumps, 6.8% to computer-aided dispensing label generation and 1.5% to other technologies. The immediate causes for technology-related errors included, poor interface between user and computer (68.1%), improper procedures or rule violations (22.1%), poor interface between user and infusion pump (4.9%), technical defects (1.9%) and others (3.0%). In 11.4% of the technology-related incidents, the error was detected after the drug had been administered. A considerable proportion of all incidents were technology-related. Most errors were due to socio-technical issues. Unintended and unanticipated errors may happen when using technologies. Therefore, when using technologies, system improvement, awareness, training and monitoring are needed to minimise medication errors. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Error analysis of supercritical water correlations using ATHLET system code under DHT conditions

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, J., E-mail: jeffrey.samuel@uoit.ca [Univ. of Ontario Inst. of Tech., Oshawa, ON (Canada)

    2014-07-01

    The thermal-hydraulic computer code ATHLET (Analysis of THermal-hydraulics of LEaks and Transients) is used for analysis of anticipated and abnormal plant transients, including safety analysis of Light Water Reactors (LWRs) and Russian Graphite-Moderated High Power Channel-type Reactors (RBMKs). The range of applicability of ATHLET has been extended to supercritical water by updating the fluid-and transport-properties packages, thus enabling the code to the used in analysis of SuperCritical Water-cooled Reactors (SCWRs). Several well-known heat-transfer correlations for supercritical fluids were added to the ATHLET code and a numerical model was created to represent an experimental test section. In this work, the error in the Heat Transfer Coefficient (HTC) calculation by the ATHLET model is studied along with the ability of the various correlations to predict different heat transfer regimes. (author)

  13. Error Analysis System for Spacecraft Navigation Using the Global Positioning System (GPS)

    Science.gov (United States)

    Truong, S. H.; Hart, R. C.; Hartman, K. R.; Tomcsik, T. L.; Searl, J. E.; Bernstein, A.

    1997-01-01

    The Flight Dynamics Division (FDD) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing improved space-navigation filtering algorithms to use the Global Positioning System (GPS) for autonomous real-time onboard orbit determination. In connection with a GPS technology demonstration on the Small Satellite Technology Initiative (SSTI)/Lewis spacecraft, FDD analysts and programmers have teamed with the GSFC Guidance, Navigation, and Control Branch to develop the GPS Enhanced Orbit Determination Experiment (GEODE) system. The GEODE system consists of a Kalman filter operating as a navigation tool for estimating the position, velocity, and additional states required to accurately navigate the orbiting Lewis spacecraft by using astrodynamic modeling and GPS measurements from the receiver. A parallel effort at the FDD is the development of a GPS Error Analysis System (GEAS) that will be used to analyze and improve navigation filtering algorithms during development phases and during in-flight calibration. For GEAS, the Kalman filter theory is extended to estimate the errors in position, velocity, and other error states of interest. The estimation of errors in physical variables at regular intervals will allow the time, cause, and effect of navigation system weaknesses to be identified. In addition, by modeling a sufficient set of navigation system errors, a system failure that causes an observed error anomaly can be traced and accounted for. The GEAS software is formulated using Object Oriented Design (OOD) techniques implemented in the C++ programming language on a Sun SPARC workstation. The Phase 1 of this effort is the development of a basic system to be used to evaluate navigation algorithms implemented in the GEODE system. This paper presents the GEAS mathematical methodology, systems and operations concepts, and software design and implementation. Results from the use of the basic system to evaluate

  14. Frame-based safety analysis approach for decision-based errors

    International Nuclear Information System (INIS)

    Fan, Chin-Feng; Yihb, Swu

    1997-01-01

    A frame-based approach is proposed to analyze decision-based errors made by automatic controllers or human operators due to erroneous reference frames. An integrated framework, Two Frame Model (TFM), is first proposed to model the dynamic interaction between the physical process and the decision-making process. Two important issues, consistency and competing processes, are raised. Consistency between the physical and logic frames makes a TFM-based system work properly. Loss of consistency refers to the failure mode that the logic frame does not accurately reflect the state of the controlled processes. Once such failure occurs, hazards may arise. Among potential hazards, the competing effect between the controller and the controlled process is the most severe one, which may jeopardize a defense-in-depth design. When the logic and physical frames are inconsistent, conventional safety analysis techniques are inadequate. We propose Frame-based Fault Tree; Analysis (FFTA) and Frame-based Event Tree Analysis (FETA) under TFM to deduce the context for decision errors and to separately generate the evolution of the logical frame as opposed to that of the physical frame. This multi-dimensional analysis approach, different from the conventional correctness-centred approach, provides a panoramic view in scenario generation. Case studies using the proposed techniques are also given to demonstrate their usage and feasibility

  15. Phase analysis in gated blood pool tomography. Detection of accessory conduction pathway

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kenichi; Bunko, Hisashi; Tada, Akira; Taki, Junichi; Nanbu, Ichiro (Kanazawa Univ. (Japan). School of Medicine)

    1984-02-01

    Phase analysis of gated blood pool study has been applied to detect the site of accessory conduction pathway (ACP) in the Wolff-Parkinson-White (WPW) syndrome; however, there was a limitation to detect the precise location of ACP by phase analysis alone. In this study, we applied phase analysis to gated blood pool tomography using seven pin hole tomography (7PT) and gated emission computed tomography (GECT) in 21 patients with WPW syndrome and 3 normal subjects. In 17 patients, the sites of ACPs were confirmed by epicardial mapping and the result of the surgical division of ACP. In 7PT, the site of ACP grossly agreed to the abnormal initial phase in phase image in 5 out of 6 patients with left cardiac type. In GECT, phase images were generated in short axial, vertical and horizontal long axial sections. In 8 out of 9 patients, the site of ACP was correctly identified by phase images, and in a patient who had two ACPs, initial phase corresponded to one of the two locations. Phase analysis of gated blood pool tomography has advantages for avoiding overlap of blood pools and for estimating three-dimensional propagation of the contraction, and can be a good adjunctive method in patients with WPW syndrome.

  16. Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

    Science.gov (United States)

    Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

    2016-01-01

    After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

  17. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

    NARCIS (Netherlands)

    Bosschaart, Nienke; van Leeuwen, Ton; Aalders, Maurice C.G.; Faber, Dirk

    2014-01-01

    We reply to the comment by Kraszewski et al on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography.” We present additional simulations evaluating the proposed window function. We conclude that our simulations show good qualitative agreement with the results of

  18. Analysis of human cerebral functions using positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Shibasaki, Takashi

    1984-01-01

    Positron emission tomography has two major advantages to analyse human cerebral functions in vivo. First, we can see the distribution of a variety of substance in the living (and doing something) human brain. Positron emitters, 11 C, 13 N, 15 O and 18 F, are made by medical cyclotron and are elements of natural substrates or easily tagged to substrate. Second, the distribution of the tracer is calculated to make a quantitative functional map in a reasonable spatial resolution over the entire brain in the same time. Not only cortical areas but also deeper structures show regional cerebral blood flow (rCBF) or local cerebral metabolic rates (LCMRs). Nowadays, PET is put to practical use for determination of mainly rCBF, LCMR for glucose (LCMRsub(glu)), LCMR for oxygen (LCMRsub(o2)) and regional cerebral blood volume (rCBV). There have been many other pilot studies, such as estimation of distribution of given neurotransmitters or modulators in the brain which also confirms the substances' role in the neuronal function, and observation of protein synthesis relating to memory function. (J.P.N.)

  19. Adaptive Green-Kubo estimates of transport coefficients from molecular dynamics based on robust error analysis

    Science.gov (United States)

    Jones, Reese E.; Mandadapu, Kranthi K.

    2012-04-01

    We present a rigorous Green-Kubo methodology for calculating transport coefficients based on on-the-fly estimates of: (a) statistical stationarity of the relevant process, and (b) error in the resulting coefficient. The methodology uses time samples efficiently across an ensemble of parallel replicas to yield accurate estimates, which is particularly useful for estimating the thermal conductivity of semi-conductors near their Debye temperatures where the characteristic decay times of the heat flux correlation functions are large. Employing and extending the error analysis of Zwanzig and Ailawadi [Phys. Rev. 182, 280 (1969)], 10.1103/PhysRev.182.280 and Frenkel [in Proceedings of the International School of Physics "Enrico Fermi", Course LXXV (North-Holland Publishing Company, Amsterdam, 1980)] to the integral of correlation, we are able to provide tight theoretical bounds for the error in the estimate of the transport coefficient. To demonstrate the performance of the method, four test cases of increasing computational cost and complexity are presented: the viscosity of Ar and water, and the thermal conductivity of Si and GaN. In addition to producing accurate estimates of the transport coefficients for these materials, this work demonstrates precise agreement of the computed variances in the estimates of the correlation and the transport coefficient with the extended theory based on the assumption that fluctuations follow a Gaussian process. The proposed algorithm in conjunction with the extended theory enables the calculation of transport coefficients with the Green-Kubo method accurately and efficiently.

  20. On the effects of systematic errors in analysis of nuclear scattering data

    International Nuclear Information System (INIS)

    Bennett, M.T.; Steward, C.; Amos, K.; Allen, L.J.

    1995-01-01

    The effects of systematic errors on elastic scattering differential cross-section data upon the assessment of quality fits to that data have been studied. Three cases are studied, namely the differential cross-section data sets from elastic scattering of 200 MeV protons from 12 C, of 350 MeV 16 O- 16 O scattering and of 288.6 MeV 12 C- 12 C scattering. First, to estimate the probability of any unknown systematic errors, select sets of data have been processed using the method of generalized cross validation; a method based upon the premise that any data set should satisfy an optimal smoothness criterion. In another case, the S function that provided a statistically significant fit to data, upon allowance for angle variation, became overdetermined. A far simpler S function form could then be found to describe the scattering process. The S functions so obtained have been used in a fixed energy inverse scattering study to specify effective, local, Schroedinger potentials for the collisions. An error analysis has been performed on the results to specify confidence levels for those interactions. 19 refs., 6 tabs., 15 figs

  1. English word frequency and recognition in bilinguals: Inter-corpus comparison and error analysis.

    Science.gov (United States)

    Shi, Lu-Feng

    2015-01-01

    This study is the second of a two-part investigation on lexical effects on bilinguals' performance on a clinical English word recognition test. Focus is on word-frequency effects using counts provided by four corpora. Frequency of occurrence was obtained for 200 NU-6 words from the Hoosier mental lexicon (HML) and three contemporary corpora, American National Corpora, Hyperspace analogue to language (HAL), and SUBTLEX(US). Correlation analysis was performed between word frequency and error rate. Ten monolinguals and 30 bilinguals participated. Bilinguals were further grouped according to their age of English acquisition and length of schooling/working in English. Word frequency significantly affected word recognition in bilinguals who acquired English late and had limited schooling/working in English. When making errors, bilinguals tended to replace the target word with a word of a higher frequency. Overall, the newer corpora outperformed the HML in predicting error rate. Frequency counts provided by contemporary corpora predict bilinguals' recognition of English monosyllabic words. Word frequency also helps explain top replacement words for misrecognized targets. Word-frequency effects are especially prominent for bilinguals foreign born and educated.

  2. Error Ellipsoid Analysis for the Diameter Measurement of Cylindroid Components Using a Laser Radar Measurement System

    Directory of Open Access Journals (Sweden)

    Zhengchun Du

    2016-05-01

    Full Text Available The use of three-dimensional (3D data in the industrial measurement field is becoming increasingly popular because of the rapid development of laser scanning techniques based on the time-of-flight principle. However, the accuracy and uncertainty of these types of measurement methods are seldom investigated. In this study, a mathematical uncertainty evaluation model for the diameter measurement of standard cylindroid components has been proposed and applied to a 3D laser radar measurement system (LRMS. First, a single-point error ellipsoid analysis for the LRMS was established. An error ellipsoid model and algorithm for diameter measurement of cylindroid components was then proposed based on the single-point error ellipsoid. Finally, four experiments were conducted using the LRMS to measure the diameter of a standard cylinder in the laboratory. The experimental results of the uncertainty evaluation consistently matched well with the predictions. The proposed uncertainty evaluation model for cylindrical diameters can provide a reliable method for actual measurements and support further accuracy improvement of the LRMS.

  3. Review of advances in human reliability analysis of errors of commission-Part 2: EOC quantification

    International Nuclear Information System (INIS)

    Reer, Bernhard

    2008-01-01

    In close connection with examples relevant to contemporary probabilistic safety assessment (PSA), a review of advances in human reliability analysis (HRA) of post-initiator errors of commission (EOCs), i.e. inappropriate actions under abnormal operating conditions, has been carried out. The review comprises both EOC identification (part 1) and quantification (part 2); part 2 is presented in this article. Emerging HRA methods in this field are: ATHEANA, MERMOS, the EOC HRA method developed by Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS), the MDTA method and CREAM. The essential advanced features are on the conceptual side, especially to envisage the modeling of multiple contexts for an EOC to be quantified (ATHEANA, MERMOS and MDTA), in order to explicitly address adverse conditions. There is promising progress in providing systematic guidance to better account for cognitive demands and tendencies (GRS, CREAM), and EOC recovery (MDTA). Problematic issues are associated with the implementation of multiple context modeling and the assessment of context-specific error probabilities. Approaches for task or error opportunity scaling (CREAM, GRS) and the concept of reference cases (ATHEANA outlook) provide promising orientations for achieving progress towards data-based quantification. Further development work is needed and should be carried out in close connection with large-scale applications of existing approaches

  4. Fractional Order Differentiation by Integration and Error Analysis in Noisy Environment

    KAUST Repository

    Liu, Dayan

    2015-03-31

    The integer order differentiation by integration method based on the Jacobi orthogonal polynomials for noisy signals was originally introduced by Mboup, Join and Fliess. We propose to extend this method from the integer order to the fractional order to estimate the fractional order derivatives of noisy signals. Firstly, two fractional order differentiators are deduced from the Jacobi orthogonal polynomial filter, using the Riemann-Liouville and the Caputo fractional order derivative definitions respectively. Exact and simple formulae for these differentiators are given by integral expressions. Hence, they can be used for both continuous-time and discrete-time models in on-line or off-line applications. Secondly, some error bounds are provided for the corresponding estimation errors. These bounds allow to study the design parameters\\' influence. The noise error contribution due to a large class of stochastic processes is studied in discrete case. The latter shows that the differentiator based on the Caputo fractional order derivative can cope with a class of noises, whose mean value and variance functions are polynomial time-varying. Thanks to the design parameters analysis, the proposed fractional order differentiators are significantly improved by admitting a time-delay. Thirdly, in order to reduce the calculation time for on-line applications, a recursive algorithm is proposed. Finally, the proposed differentiator based on the Riemann-Liouville fractional order derivative is used to estimate the state of a fractional order system and numerical simulations illustrate the accuracy and the robustness with respect to corrupting noises.

  5. Human reliability analysis of errors of commission: a review of methods and applications

    Energy Technology Data Exchange (ETDEWEB)

    Reer, B

    2007-06-15

    Illustrated by specific examples relevant to contemporary probabilistic safety assessment (PSA), this report presents a review of human reliability analysis (HRA) addressing post initiator errors of commission (EOCs), i.e. inappropriate actions under abnormal operating conditions. The review addressed both methods and applications. Emerging HRA methods providing advanced features and explicit guidance suitable for PSA are: A Technique for Human Event Analysis (ATHEANA, key publications in 1998/2000), Methode d'Evaluation de la Realisation des Missions Operateur pour la Surete (MERMOS, 1998/2000), the EOC HRA method developed by the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS, 2003), the Misdiagnosis Tree Analysis (MDTA) method (2005/2006), the Cognitive Reliability and Error Analysis Method (CREAM, 1998), and the Commission Errors Search and Assessment (CESA) method (2002/2004). As a result of a thorough investigation of various PSA/HRA applications, this paper furthermore presents an overview of EOCs (termination of safety injection, shutdown of secondary cooling, etc.) referred to in predictive studies and a qualitative review of cases of EOC quantification. The main conclusions of the review of both the methods and the EOC HRA cases are: (1) The CESA search scheme, which proceeds from possible operator actions to the affected systems to scenarios, may be preferable because this scheme provides a formalized way for identifying relatively important scenarios with EOC opportunities; (2) an EOC identification guidance like CESA, which is strongly based on the procedural guidance and important measures of systems or components affected by inappropriate actions, however should pay some attention to EOCs associated with familiar but non-procedural actions and EOCs leading to failures of manually initiated safety functions. (3) Orientations of advanced EOC quantification comprise a) modeling of multiple contexts for a given scenario, b) accounting for

  6. Human reliability analysis of errors of commission: a review of methods and applications

    International Nuclear Information System (INIS)

    Reer, B.

    2007-06-01

    Illustrated by specific examples relevant to contemporary probabilistic safety assessment (PSA), this report presents a review of human reliability analysis (HRA) addressing post initiator errors of commission (EOCs), i.e. inappropriate actions under abnormal operating conditions. The review addressed both methods and applications. Emerging HRA methods providing advanced features and explicit guidance suitable for PSA are: A Technique for Human Event Analysis (ATHEANA, key publications in 1998/2000), Methode d'Evaluation de la Realisation des Missions Operateur pour la Surete (MERMOS, 1998/2000), the EOC HRA method developed by the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS, 2003), the Misdiagnosis Tree Analysis (MDTA) method (2005/2006), the Cognitive Reliability and Error Analysis Method (CREAM, 1998), and the Commission Errors Search and Assessment (CESA) method (2002/2004). As a result of a thorough investigation of various PSA/HRA applications, this paper furthermore presents an overview of EOCs (termination of safety injection, shutdown of secondary cooling, etc.) referred to in predictive studies and a qualitative review of cases of EOC quantification. The main conclusions of the review of both the methods and the EOC HRA cases are: (1) The CESA search scheme, which proceeds from possible operator actions to the affected systems to scenarios, may be preferable because this scheme provides a formalized way for identifying relatively important scenarios with EOC opportunities; (2) an EOC identification guidance like CESA, which is strongly based on the procedural guidance and important measures of systems or components affected by inappropriate actions, however should pay some attention to EOCs associated with familiar but non-procedural actions and EOCs leading to failures of manually initiated safety functions. (3) Orientations of advanced EOC quantification comprise a) modeling of multiple contexts for a given scenario, b) accounting for

  7. Ultrastructural Analysis of Urinary Stones by Microfocus Computed Tomography and Comparison with Chemical Analysis

    Directory of Open Access Journals (Sweden)

    Tolga Karakan

    2016-06-01

    Full Text Available Objective: To investigate the ultra-structure of urinary system stones using micro-focus computed tomography (MCT, which makes non-destructive analysis and to compare with wet chemical analysis. Methods: This study was carried out at the Ankara Train­ing and Research hospital. Renal stones, removed from 30 patients during percutaneous nephrolithotomy (PNL surgery, were included in the study. The stones were blindly evaluated by the specialists with MCT and chemi­cal analysis. Results: The comparison of the stone components be­tween chemical analysis and MCT, showed that the rate of consistence was very low (p0.05. It was also seen that there was no significant relation between its 3D structure being heterogeneous or homogenous. Conclusion: The stone analysis with MCT is a time con­suming and costly method. This method is useful to un­derstand the mechanisms of stone formation and an im­portant guide to develop the future treatment modalities.

  8. Numerical analysis of modal tomography for solar multi-conjugate adaptive optics

    International Nuclear Information System (INIS)

    Dong Bing; Ren Deqing; Zhang Xi

    2012-01-01

    Multi-conjugate adaptive optics (MCAO) can considerably extend the corrected field of view with respect to classical adaptive optics, which will benefit solar observation in many aspects. In solar MCAO, the Sun structure is utilized to provide multiple guide stars and a modal tomography approach is adopted to implement three-dimensional wavefront restorations. The principle of modal tomography is briefly reviewed and a numerical simulation model is built with three equivalent turbulent layers and a different number of guide stars. Our simulation results show that at least six guide stars are required for an accurate wavefront reconstruction in the case of three layers, and only three guide stars are needed in the two layer case. Finally, eigenmode analysis results are given to reveal the singular modes that cannot be precisely retrieved in the tomography process.

  9. A basic framework for the analysis of the human error potential due to the computerization in nuclear power plants

    International Nuclear Information System (INIS)

    Lee, Y. H.

    1999-01-01

    Computerization and its vivid benefits expected in the nuclear power plant design cannot be realized without verifying the inherent safety problems. Human error aspect is also included in the verification issues. The verification spans from the perception of the changes in operation functions such as automation to the unfamiliar experience of operators due to the interface change. Therefore, a new framework for human error analysis might capture both the positive and the negative effect of the computerization. This paper suggest a basic framework for error identification through the review of the existing human error studies and the experience of computerizations in nuclear power plants

  10. Accuracy improvement of the H-drive air-levitating wafer inspection stage based on error analysis and compensation

    Science.gov (United States)

    Zhang, Fan; Liu, Pinkuan

    2018-04-01

    In order to improve the inspection precision of the H-drive air-bearing stage for wafer inspection, in this paper the geometric error of the stage is analyzed and compensated. The relationship between the positioning errors and error sources are initially modeled, and seven error components are identified that are closely related to the inspection accuracy. The most effective factor that affects the geometric error is identified by error sensitivity analysis. Then, the Spearman rank correlation method is applied to find the correlation between different error components, aiming at guiding the accuracy design and error compensation of the stage. Finally, different compensation methods, including the three-error curve interpolation method, the polynomial interpolation method, the Chebyshev polynomial interpolation method, and the B-spline interpolation method, are employed within the full range of the stage, and their results are compared. Simulation and experiment show that the B-spline interpolation method based on the error model has better compensation results. In addition, the research result is valuable for promoting wafer inspection accuracy and will greatly benefit the semiconductor industry.

  11. Error analysis of motion correction method for laser scanning of moving objects

    Science.gov (United States)

    Goel, S.; Lohani, B.

    2014-05-01

    The limitation of conventional laser scanning methods is that the objects being scanned should be static. The need of scanning moving objects has resulted in the development of new methods capable of generating correct 3D geometry of moving objects. Limited literature is available showing development of very few methods capable of catering to the problem of object motion during scanning. All the existing methods utilize their own models or sensors. Any studies on error modelling or analysis of any of the motion correction methods are found to be lacking in literature. In this paper, we develop the error budget and present the analysis of one such `motion correction' method. This method assumes availability of position and orientation information of the moving object which in general can be obtained by installing a POS system on board or by use of some tracking devices. It then uses this information along with laser scanner data to apply correction to laser data, thus resulting in correct geometry despite the object being mobile during scanning. The major application of this method lie in the shipping industry to scan ships either moving or parked in the sea and to scan other objects like hot air balloons or aerostats. It is to be noted that the other methods of "motion correction" explained in literature can not be applied to scan the objects mentioned here making the chosen method quite unique. This paper presents some interesting insights in to the functioning of "motion correction" method as well as a detailed account of the behavior and variation of the error due to different sensor components alone and in combination with each other. The analysis can be used to obtain insights in to optimal utilization of available components for achieving the best results.

  12. Republished error management: Descriptions of verbal communication errors between staff. An analysis of 84 root cause analysis-reports from Danish hospitals

    DEFF Research Database (Denmark)

    Rabøl, Louise Isager; Andersen, Mette Lehmann; Østergaard, Doris

    2011-01-01

    Introduction Poor teamwork and communication between healthcare staff are correlated to patient safety incidents. However, the organisational factors responsible for these issues are unexplored. Root cause analyses (RCA) use human factors thinking to analyse the systems behind severe patient safety...... (30%)), communication errors between junior and senior staff members (11 (25%)), hesitance in speaking up (10 (23%)) and communication errors during teamwork (8 (18%)). The kappa values were 0.44-0.78. Unproceduralized communication and information exchange via telephone, related to transfer between...... incidents. The RCARs rich descriptions of the incidents revealed the organisational factors and needs related to these errors....

  13. Infant search and object permanence: a meta-analysis of the A-not-B error.

    Science.gov (United States)

    Wellman, H M; Cross, D; Bartsch, K

    1987-01-01

    Research on Piaget's stage 4 object concept has failed to reveal a clear or consistent pattern of results. Piaget found that 8-12-month-old infants would make perserverative errors; his explanation for this phenomenon was that the infant's concept of the object was contextually dependent on his or her actions. Some studies designed to test Piaget's explanation have replicated Piaget's basic finding, yet many have found no preference for the A location or the B location or an actual preference for the B location. More recently, researchers have attempted to uncover the causes for these results concerning the A-not-B error. Again, however, different studies have yielded different results, and qualitative reviews have failed to yield a consistent explanation for the results of the individual studies. This state of affairs suggests that the phenomenon may simply be too complex to be captured by individual studies varying 1 factor at a time and by reviews based on similar qualitative considerations. Therefore, the current investigation undertook a meta-analysis, a synthesis capturing the quantitative information across the now sizable number of studies. We entered several important factors into the meta-analysis, including the effects of age, the number of A trials, the length of delay between hiding and search, the number of locations, the distances between locations, and the distinctive visual properties of the hiding arrays. Of these, the analysis consistently indicated that age, delay, and number of hiding locations strongly influence infants' search. The pattern of specific findings also yielded new information about infant search. A general characterization of the results is that, at every age, both above-chance and below-chance performance was observed. That is, at each age at least 1 combination of delay and number of locations yielded above-chance A-not-B errors or significant perseverative search. At the same time, at each age at least 1 alternative

  14. Error analysis of numerical gravitational waveforms from coalescing binary black holes

    Science.gov (United States)

    Fong, Heather; Chu, Tony; Kumar, Prayush; Pfeiffer, Harald; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela; SXS Collaboration

    2016-03-01

    The Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) has finished a successful first observation run and will commence its second run this summer. Detection of compact object binaries utilizes matched-filtering, which requires a vast collection of highly accurate gravitational waveforms. This talk will present a set of about 100 new aligned-spin binary black hole simulations. I will discuss their properties, including a detailed error analysis, which demonstrates that the numerical waveforms are sufficiently accurate for gravitational wave detection purposes, as well as for parameter estimation purposes.

  15. Review of advances in human reliability analysis of errors of commission, Part 1: EOC identification

    International Nuclear Information System (INIS)

    Reer, Bernhard

    2008-01-01

    In close connection with examples relevant to contemporary probabilistic safety assessment (PSA), a review of advances in human reliability analysis (HRA) of post-initiator errors of commission (EOCs), i.e. inappropriate actions under abnormal operating conditions, has been carried out. The review comprises both EOC identification (part 1) and quantification (part 2); part 1 is presented in this article. Emerging HRA methods addressing the problem of EOC identification are: A Technique for Human Event Analysis (ATHEANA), the EOC HRA method developed by Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS), the Misdiagnosis Tree Analysis (MDTA) method, and the Commission Errors Search and Assessment (CESA) method. Most of the EOCs referred to in predictive studies comprise the stop of running or the inhibition of anticipated functions; a few comprise the start of a function. The CESA search scheme-which proceeds from possible operator actions to the affected systems to scenarios and uses procedures and importance measures as key sources of input information-provides a formalized way for identifying relatively important scenarios with EOC opportunities. In the implementation however, attention should be paid regarding EOCs associated with familiar but non-procedural actions and EOCs leading to failures of manually initiated safety functions

  16. Flight Technical Error Analysis of the SATS Higher Volume Operations Simulation and Flight Experiments

    Science.gov (United States)

    Williams, Daniel M.; Consiglio, Maria C.; Murdoch, Jennifer L.; Adams, Catherine H.

    2005-01-01

    This paper provides an analysis of Flight Technical Error (FTE) from recent SATS experiments, called the Higher Volume Operations (HVO) Simulation and Flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with today s system (baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to today s system. In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative Human in the Loop (HITL) studies of SATS HVO and Baseline operations.

  17. Earth orientation from lunar laser ranging and an error analysis of polar motion services

    Science.gov (United States)

    Dickey, J. O.; Newhall, X. X.; Williams, J. G.

    1985-01-01

    Lunar laser ranging (LLR) data are obtained on the basis of the timing of laser pulses travelling from observatories on earth to retroreflectors placed on the moon's surface during the Apollo program. The modeling and analysis of the LLR data can provide valuable insights into earth's dynamics. The feasibility to model accurately the lunar orbit over the full 13-year observation span makes it possible to conduct relatively long-term studies of variations in the earth's rotation. A description is provided of general analysis techniques, and the calculation of universal time (UT1) from LLR is discussed. Attention is also given to a summary of intercomparisons with different techniques, polar motion results and intercomparisons, and a polar motion error analysis.

  18. AN ANALYSIS OF ACEHNESE EFL STUDENTS’ GRAMMATICAL ERRORS IN WRITING RECOUNT TEXTS

    Directory of Open Access Journals (Sweden)

    Qudwatin Nisak M. Isa

    2017-11-01

    Full Text Available This study aims at finding empirical evidence of the most common types of grammatical errors and sources of errors in recount texts written by the first-year students of SMAS Babul Maghfirah, Aceh Besar. The subject of the study was a collection of students’ personal writing documents of recount texts about their lives experience. The students’ recount texts were analyzed by referring to Betty S. Azar classification and Richard’s theory on sources of errors. The findings showed that the total number of error is 436. Two frequent types of grammatical errors were Verb Tense and Word Choice. The major sources of error were Intralingual Error, Interference Error and Developmental Error respectively. Furthermore, the findings suggest that it is necessary for EFL teachers to apply appropriate techniques and strategies in teaching recount texts, which focus on past tense and language features of the text in order to reduce the possible errors to be made by the students.

  19. Analysis of the Mean Absolute Error (MAE) and the Root Mean Square Error (RMSE) in Assessing Rounding Model

    Science.gov (United States)

    Wang, Weijie; Lu, Yanmin

    2018-03-01

    Most existing Collaborative Filtering (CF) algorithms predict a rating as the preference of an active user toward a given item, which is always a decimal fraction. Meanwhile, the actual ratings in most data sets are integers. In this paper, we discuss and demonstrate why rounding can bring different influences to these two metrics; prove that rounding is necessary in post-processing of the predicted ratings, eliminate of model prediction bias, improving the accuracy of the prediction. In addition, we also propose two new rounding approaches based on the predicted rating probability distribution, which can be used to round the predicted rating to an optimal integer rating, and get better prediction accuracy compared to the Basic Rounding approach. Extensive experiments on different data sets validate the correctness of our analysis and the effectiveness of our proposed rounding approaches.

  20. Secondary data analysis of large data sets in urology: successes and errors to avoid.

    Science.gov (United States)

    Schlomer, Bruce J; Copp, Hillary L

    2014-03-01

    Secondary data analysis is the use of data collected for research by someone other than the investigator. In the last several years there has been a dramatic increase in the number of these studies being published in urological journals and presented at urological meetings, especially involving secondary data analysis of large administrative data sets. Along with this expansion, skepticism for secondary data analysis studies has increased for many urologists. In this narrative review we discuss the types of large data sets that are commonly used for secondary data analysis in urology, and discuss the advantages and disadvantages of secondary data analysis. A literature search was performed to identify urological secondary data analysis studies published since 2008 using commonly used large data sets, and examples of high quality studies published in high impact journals are given. We outline an approach for performing a successful hypothesis or goal driven secondary data analysis study and highlight common errors to avoid. More than 350 secondary data analysis studies using large data sets have been published on urological topics since 2008 with likely many more studies presented at meetings but never published. Nonhypothesis or goal driven studies have likely constituted some of these studies and have probably contributed to the increased skepticism of this type of research. However, many high quality, hypothesis driven studies addressing research questions that would have been difficult to conduct with other methods have been performed in the last few years. Secondary data analysis is a powerful tool that can address questions which could not be adequately studied by another method. Knowledge of the limitations of secondary data analysis and of the data sets used is critical for a successful study. There are also important errors to avoid when planning and performing a secondary data analysis study. Investigators and the urological community need to strive to use

  1. Results of a nuclear power plant Application of a new technique for human error analysis (ATHEANA)

    International Nuclear Information System (INIS)

    Forester, J.A.; Whitehead, D.W.; Kolaczkowski, A.M.; Thompson, C.M.

    1997-01-01

    A new method to analyze human errors has been demonstrated at a pressurized water reactor (PWR) nuclear power plant. This was the first application of the new method referred to as A Technique for Human Error Analysis (ATHEANA). The main goals of the demonstration were to test the ATHEANA process as described in the frame-of-reference manual and the implementation guideline, test a training package developed for the method, test the hypothesis that plant operators and trainers have significant insight into the error-forcing-contexts (EFCs) that can make unsafe actions (UAs) more likely, and to identify ways to improve the method and its documentation. A set of criteria to evaluate the open-quotes successclose quotes of the ATHEANA method as used in the demonstration was identified. A human reliability analysis (HRA) team was formed that consisted of an expert in probabilistic risk assessment (PRA) with some background in HRA (not ATHEANA) and four personnel from the nuclear power plant. Personnel from the plant included two individuals from their PRA staff and two individuals from their training staff. Both individuals from training are currently licensed operators and one of them was a senior reactor operator open-quotes on shiftclose quotes until a few months before the demonstration. The demonstration was conducted over a 5 month period and was observed by members of the Nuclear Regulatory Commission's ATHEANA development team, who also served as consultants to the HRA team when necessary. Example results of the demonstration to date, including identified human failure events (HFEs), UAs, and EFCs are discussed. Also addressed is how simulator exercises are used in the ATHEANA demonstration project

  2. Teamwork and error in the operating room: analysis of skills and roles.

    Science.gov (United States)

    Catchpole, K; Mishra, A; Handa, A; McCulloch, P

    2008-04-01

    To analyze the effects of surgical, anesthetic, and nursing teamwork skills on technical outcomes. The value of team skills in reducing adverse events in the operating room is presently receiving considerable attention. Current work has not yet identified in detail how the teamwork and communication skills of surgeons, anesthetists, and nurses affect the course of an operation. Twenty-six laparoscopic cholecystectomies and 22 carotid endarterectomies were studied using direct observation methods. For each operation, teams' skills were scored for the whole team, and for nursing, surgical, and anesthetic subteams on 4 dimensions (leadership and management [LM]; teamwork and cooperation; problem solving and decision making; and situation awareness). Operating time, errors in surgical technique, and other procedural problems and errors were measured as outcome parameters for each operation. The relationships between teamwork scores and these outcome parameters within each operation were examined using analysis of variance and linear regression. Surgical (F(2,42) = 3.32, P = 0.046) and anesthetic (F(2,42) = 3.26, P = 0.048) LM had significant but opposite relationships with operating time in each operation: operating time increased significantly with higher anesthetic but decreased with higher surgical LM scores. Errors in surgical technique had a strong association with surgical situation awareness (F(2,42) = 7.93, P skills of the nurses (F(5,1) = 3.96, P = 0.027). Detailed analysis of team interactions and dimensions is feasible and valuable, yielding important insights into relationships between nontechnical skills, technical performance, and operative duration. These results support the concept that interventions designed to improve teamwork and communication may have beneficial effects on technical performance and patient outcome.

  3. Inversion, error analysis, and validation of GPS/MET occultation data

    Directory of Open Access Journals (Sweden)

    A. K. Steiner

    Full Text Available The global positioning system meteorology (GPS/MET experiment was the first practical demonstration of global navigation satellite system (GNSS-based active limb sounding employing the radio occultation technique. This method measures, as principal observable and with millimetric accuracy, the excess phase path (relative to propagation in vacuum of GNSS-transmitted radio waves caused by refraction during passage through the Earth's neutral atmosphere and ionosphere in limb geometry. It shows great potential utility for weather and climate system studies in providing an unique combination of global coverage, high vertical resolution and accuracy, long-term stability, and all-weather capability. We first describe our GPS/MET data processing scheme from excess phases via bending angles to the neutral atmospheric parameters refractivity, density, pressure and temperature. Special emphasis is given to ionospheric correction methodology and the inversion of bending angles to refractivities, where we introduce a matrix inversion technique (instead of the usual integral inversion. The matrix technique is shown to lead to identical results as integral inversion but is more directly extendable to inversion by optimal estimation. The quality of GPS/MET-derived profiles is analyzed with an error estimation analysis employing a Monte Carlo technique. We consider statistical errors together with systematic errors due to upper-boundary initialization of the retrieval by a priori bending angles. Perfect initialization and properly smoothed statistical errors allow for better than 1 K temperature retrieval accuracy up to the stratopause. No initialization and statistical errors yield better than 1 K accuracy up to 30 km but less than 3 K accuracy above 40 km. Given imperfect initialization, biases >2 K propagate down to below 30 km height in unfavorable realistic cases. Furthermore, results of a statistical validation of GPS/MET profiles through comparison

  4. A Simple Exact Error Rate Analysis for DS-CDMA with Arbitrary Pulse Shape in Flat Nakagami Fading

    Science.gov (United States)

    Rahman, Mohammad Azizur; Sasaki, Shigenobu; Kikuchi, Hisakazu; Harada, Hiroshi; Kato, Shuzo

    A simple exact error rate analysis is presented for random binary direct sequence code division multiple access (DS-CDMA) considering a general pulse shape and flat Nakagami fading channel. First of all, a simple model is developed for the multiple access interference (MAI). Based on this, a simple exact expression of the characteristic function (CF) of MAI is developed in a straight forward manner. Finally, an exact expression of error rate is obtained following the CF method of error rate analysis. The exact error rate so obtained can be much easily evaluated as compared to the only reliable approximate error rate expression currently available, which is based on the Improved Gaussian Approximation (IGA).

  5. SU-E-I-83: Error Analysis of Multi-Modality Image-Based Volumes of Rodent Solid Tumors Using a Preclinical Multi-Modality QA Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y [University of Kansas Hospital, Kansas City, KS (United States); Fullerton, G; Goins, B [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    2015-06-15

    Purpose: In our previous study a preclinical multi-modality quality assurance (QA) phantom that contains five tumor-simulating test objects with 2, 4, 7, 10 and 14 mm diameters was developed for accurate tumor size measurement by researchers during cancer drug development and testing. This study analyzed the errors during tumor volume measurement from preclinical magnetic resonance (MR), micro-computed tomography (micro- CT) and ultrasound (US) images acquired in a rodent tumor model using the preclinical multi-modality QA phantom. Methods: Using preclinical 7-Tesla MR, US and micro-CT scanners, images were acquired of subcutaneous SCC4 tumor xenografts in nude rats (3–4 rats per group; 5 groups) along with the QA phantom using the same imaging protocols. After tumors were excised, in-air micro-CT imaging was performed to determine reference tumor volume. Volumes measured for the rat tumors and phantom test objects were calculated using formula V = (π/6)*a*b*c where a, b and c are the maximum diameters in three perpendicular dimensions determined by the three imaging modalities. Then linear regression analysis was performed to compare image-based tumor volumes with the reference tumor volume and known test object volume for the rats and the phantom respectively. Results: The slopes of regression lines for in-vivo tumor volumes measured by three imaging modalities were 1.021, 1.101 and 0.862 for MRI, micro-CT and US respectively. For phantom, the slopes were 0.9485, 0.9971 and 0.9734 for MRI, micro-CT and US respectively. Conclusion: For both animal and phantom studies, random and systematic errors were observed. Random errors were observer-dependent and systematic errors were mainly due to selected imaging protocols and/or measurement method. In the animal study, there were additional systematic errors attributed to ellipsoidal assumption for tumor shape. The systematic errors measured using the QA phantom need to be taken into account to reduce measurement

  6. Instanton-based techniques for analysis and reduction of error floors of LDPC codes

    International Nuclear Information System (INIS)

    Chertkov, Michael; Chilappagari, Shashi K.; Stepanov, Mikhail G.; Vasic, Bane

    2008-01-01

    We describe a family of instanton-based optimization methods developed recently for the analysis of the error floors of low-density parity-check (LDPC) codes. Instantons are the most probable configurations of the channel noise which result in decoding failures. We show that the general idea and the respective optimization technique are applicable broadly to a variety of channels, discrete or continuous, and variety of sub-optimal decoders. Specifically, we consider: iterative belief propagation (BP) decoders, Gallager type decoders, and linear programming (LP) decoders performing over the additive white Gaussian noise channel (AWGNC) and the binary symmetric channel (BSC). The instanton analysis suggests that the underlying topological structures of the most probable instanton of the same code but different channels and decoders are related to each other. Armed with this understanding of the graphical structure of the instanton and its relation to the decoding failures, we suggest a method to construct codes whose Tanner graphs are free of these structures, and thus have less significant error floors.

  7. Instanton-based techniques for analysis and reduction of error floor of LDPC codes

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Chilappagari, Shashi K [Los Alamos National Laboratory; Stepanov, Mikhail G [Los Alamos National Laboratory; Vasic, Bane [SENIOR MEMBER, IEEE

    2008-01-01

    We describe a family of instanton-based optimization methods developed recently for the analysis of the error floors of low-density parity-check (LDPC) codes. Instantons are the most probable configurations of the channel noise which result in decoding failures. We show that the general idea and the respective optimization technique are applicable broadly to a variety of channels, discrete or continuous, and variety of sub-optimal decoders. Specifically, we consider: iterative belief propagation (BP) decoders, Gallager type decoders, and linear programming (LP) decoders performing over the additive white Gaussian noise channel (AWGNC) and the binary symmetric channel (BSC). The instanton analysis suggests that the underlying topological structures of the most probable instanton of the same code but different channels and decoders are related to each other. Armed with this understanding of the graphical structure of the instanton and its relation to the decoding failures, we suggest a method to construct codes whose Tanner graphs are free of these structures, and thus have less significant error floors.

  8. Wavelet analysis enables system-independent texture analysis of optical coherence tomography images

    Science.gov (United States)

    Lingley-Papadopoulos, Colleen A.; Loew, Murray H.; Zara, Jason M.

    2009-07-01

    Texture analysis for tissue characterization is a current area of optical coherence tomography (OCT) research. We discuss some of the differences between OCT systems and the effects those differences have on the resulting images and subsequent image analysis. In addition, as an example, two algorithms for the automatic recognition of bladder cancer are compared: one that was developed on a single system with no consideration for system differences, and one that was developed to address the issues associated with system differences. The first algorithm had a sensitivity of 73% and specificity of 69% when tested using leave-one-out cross-validation on data taken from a single system. When tested on images from another system with a different central wavelength, however, the method classified all images as cancerous regardless of the true pathology. By contrast, with the use of wavelet analysis and the removal of system-dependent features, the second algorithm reported sensitivity and specificity values of 87 and 58%, respectively, when trained on images taken with one imaging system and tested on images taken with another.

  9. Wavelet analysis enables system-independent texture analysis of optical coherence tomography images.

    Science.gov (United States)

    Lingley-Papadopoulos, Colleen A; Loew, Murray H; Zara, Jason M

    2009-01-01

    Texture analysis for tissue characterization is a current area of optical coherence tomography (OCT) research. We discuss some of the differences between OCT systems and the effects those differences have on the resulting images and subsequent image analysis. In addition, as an example, two algorithms for the automatic recognition of bladder cancer are compared: one that was developed on a single system with no consideration for system differences, and one that was developed to address the issues associated with system differences. The first algorithm had a sensitivity of 73% and specificity of 69% when tested using leave-one-out cross-validation on data taken from a single system. When tested on images from another system with a different central wavelength, however, the method classified all images as cancerous regardless of the true pathology. By contrast, with the use of wavelet analysis and the removal of system-dependent features, the second algorithm reported sensitivity and specificity values of 87 and 58%, respectively, when trained on images taken with one imaging system and tested on images taken with another.

  10. Web-Based Information Management System for the Investigation, Reporting, and Analysis of Human Error in Naval Aviation Maintenance

    National Research Council Canada - National Science Library

    Boex, Anthony

    2001-01-01

    .... The Human Factors Analysis and Classification System-Maintenance Extension (HFACS-ME) taxonomy, a framework for classifying and analyzing the presence of maintenance errors that lead to mishaps, is the foundation of this tool...

  11. Multimodal imaging analysis of single-photon emission computed tomography and magnetic resonance tomography for improving diagnosis of Parkinson's disease

    International Nuclear Information System (INIS)

    Barthel, H.; Georgi, P.; Slomka, P.; Dannenberg, C.; Kahn, T.

    2000-01-01

    Parkinson's disease (PD) is characterized by a degeneration of nigrostriated dopaminergic neurons, which can be imaged with 123 I-labeled 2β-carbomethoxy-3β-(4-iodophenyl) tropane ([ 123 I]β-CIT) and single-photon emission computed tomography (SPECT). However, the quality of the region of interest (ROI) technique used for quantitative analysis of SPECT data is compromised by limited anatomical information in the images. We investigated whether the diagnosis of PD can be improved by combining the use of SPECT images with morphological image data from magnetic resonance imaging (MRI)/computed tomography (CT). We examined 27 patients (8 men, 19 women; aged 55±13 years) with PD (Hoehn and Yahr stage 2.1±0.8) by high-resolution [ 123 I]β-CIT SPECT (185-200 MBq, Ceraspect camera). SPECT images were analyzed both by a unimodal technique (ROIs defined directly within the SPECT studies) and a multimodal technique (ROIs defined within individual MRI/CT studies and transferred to the corresponding interactively coregistered SPECT studies). [ 123 I]β-CIT binding ratios (cerebellum as reference), which were obtained for heads of caudate nuclei (CA), putamina (PU), and global striatal structures were compared with clinical parameters. Differences between contra- and ipsilateral (related to symptom dominance) striatal [ 123 I]β-CIT binding ratios proved to be larger in the multimodal ROI technique than in the unimodal approach (e.g., for PU: 1.2*** vs. 0.7**). Binding ratios obtained by the unimodal ROI technique were significantly correlated with those of the multimodal technique (e.g., for CA: y=0.97x+2.8; r=0.70; P com subscore (r=-0.49* vs. -0.32). These results show that the impact of [ 123 I]β-CIT SPECT for diagnosing PD is affected by the method used to analyze the SPECT images. The described multimodal approach, which is based on coregistration of SPECT and morphological imaging data, leads to improved determination of the degree of this dopaminergic disorder

  12. Analysis of the effects of Eye-Tracker performance on the pulse positioning errors during refractive surgery☆

    Science.gov (United States)

    Arba-Mosquera, Samuel; Aslanides, Ioannis M.

    2012-01-01

    Purpose To analyze the effects of Eye-Tracker performance on the pulse positioning errors during refractive surgery. Methods A comprehensive model, which directly considers eye movements, including saccades, vestibular, optokinetic, vergence, and miniature, as well as, eye-tracker acquisition rate, eye-tracker latency time, scanner positioning time, laser firing rate, and laser trigger delay have been developed. Results Eye-tracker acquisition rates below 100 Hz correspond to pulse positioning errors above 1.5 mm. Eye-tracker latency times to about 15 ms correspond to pulse positioning errors of up to 3.5 mm. Scanner positioning times to about 9 ms correspond to pulse positioning errors of up to 2 mm. Laser firing rates faster than eye-tracker acquisition rates basically duplicate pulse-positioning errors. Laser trigger delays to about 300 μs have minor to no impact on pulse-positioning errors. Conclusions The proposed model can be used for comparison of laser systems used for ablation processes. Due to the pseudo-random nature of eye movements, positioning errors of single pulses are much larger than observed decentrations in the clinical settings. There is no single parameter that ‘alone’ minimizes the positioning error. It is the optimal combination of the several parameters that minimizes the error. The results of this analysis are important to understand the limitations of correcting very irregular ablation patterns.

  13. Analysis of Relationships between the Level of Errors in Leg and Monofin Movement and Stroke Parameters in Monofin Swimming

    Science.gov (United States)

    Rejman, Marek

    2013-01-01

    The aim of this study was to analyze the error structure in propulsive movements with regard to its influence on monofin swimming speed. The random cycles performed by six swimmers were filmed during a progressive test (900m). An objective method to estimate errors committed in the area of angular displacement of the feet and monofin segments was employed. The parameters were compared with a previously described model. Mutual dependences between the level of errors, stroke frequency, stroke length and amplitude in relation to swimming velocity were analyzed. The results showed that proper foot movements and the avoidance of errors, arising at the distal part of the fin, ensure the progression of swimming speed. The individual stroke parameters distribution which consists of optimally increasing stroke frequency to the maximal possible level that enables the stabilization of stroke length leads to the minimization of errors. Identification of key elements in the stroke structure based on the analysis of errors committed should aid in improving monofin swimming technique. Key points The monofin swimming technique was evaluated through the prism of objectively defined errors committed by the swimmers. The dependences between the level of errors, stroke rate, stroke length and amplitude in relation to swimming velocity were analyzed. Optimally increasing stroke rate to the maximal possible level that enables the stabilization of stroke length leads to the minimization of errors. Propriety foot movement and the avoidance of errors arising at the distal part of fin, provide for the progression of swimming speed. The key elements improving monofin swimming technique, based on the analysis of errors committed, were designated. PMID:24149742

  14. Mobility and Position Error Analysis of a Complex Planar Mechanism with Redundant Constraints

    Science.gov (United States)

    Sun, Qipeng; Li, Gangyan

    2018-03-01

    Nowadays mechanisms with redundant constraints have been created and attracted much attention for their merits. The mechanism of the redundant constraints in a mechanical system is analyzed in this paper. A analysis method of Planar Linkage with a repetitive structure is proposed to get the number and type of constraints. According to the difference of applications and constraint characteristics, the redundant constraints are divided into the theoretical planar redundant constraints and the space-planar redundant constraints. And the calculation formula for the number of redundant constraints and type of judging method are carried out. And a complex mechanism with redundant constraints is analyzed of the influence about redundant constraints on mechanical performance. With the combination of theoretical derivation and simulation research, a mechanism analysis method is put forward about the position error of complex mechanism with redundant constraints. It points out the direction on how to eliminate or reduce the influence of redundant constraints.

  15. Error analysis of supersonic air-to-air ejector schlieren pictures

    Directory of Open Access Journals (Sweden)

    Kolář J.

    2013-04-01

    Full Text Available The scope of this article is focused on general analysis of errors and uncertainties possibly arising from CFD-to-schlieren pictures matching. Analysis is based on classic analytical equations. These are firstly evaluated with the presumption of constant density gradient along the ray course. In other words, the deflection of light-ray caused by density gradient is negligible in compare to the cross size of constant gradient area. It is the aim of this work to determine, whether this presumption is applicable in case of supersonic air-to-air ejector. The colour and black and white schlieren pictures are carried out and compared to CFD results. Simulations had covered various eddy viscosities. Computed pressure gradients are transformed into deflection angles and further to ray displacement. Resulting computed light- ray deflection is matched to experimental results

  16. Fault Analysis of Wind Turbines Based on Error Messages and Work Orders

    DEFF Research Database (Denmark)

    Borchersen, Anders Bech; Larsen, Jesper Abildgaard; Stoustrup, Jakob

    2012-01-01

    describing the service performed at the individual turbines. The auto generated alarms are analysed by applying a cleaning procedure to identify the alarms related to components. A severity, occurrence, and detection analysis is performed on the work orders. The outcome of the two analyses are then compared......In this paper data describing the operation and maintenance of an offshore wind farm is presented and analysed. Two different sets of data is presented; the first is auto generated error messages from the Supervisory Control and Data Acquisition (SCADA) system, the other is the work orders...... to identify common fault types and areas where further data analysis would be beneficial for improving the operation and maintenance of wind turbines in the future....

  17. Error performance analysis in K-tier uplink cellular networks using a stochastic geometric approach

    KAUST Repository

    Afify, Laila H.

    2015-09-14

    In this work, we develop an analytical paradigm to analyze the average symbol error probability (ASEP) performance of uplink traffic in a multi-tier cellular network. The analysis is based on the recently developed Equivalent-in-Distribution approach that utilizes stochastic geometric tools to account for the network geometry in the performance characterization. Different from the other stochastic geometry models adopted in the literature, the developed analysis accounts for important communication system parameters and goes beyond signal-to-interference-plus-noise ratio characterization. That is, the presented model accounts for the modulation scheme, constellation type, and signal recovery techniques to model the ASEP. To this end, we derive single integral expressions for the ASEP for different modulation schemes due to aggregate network interference. Finally, all theoretical findings of the paper are verified via Monte Carlo simulations.

  18. Analysis of family-wise error rates in statistical parametric mapping using random field theory.

    Science.gov (United States)

    Flandin, Guillaume; Friston, Karl J

    2017-11-01

    This technical report revisits the analysis of family-wise error rates in statistical parametric mapping-using random field theory-reported in (Eklund et al. []: arXiv 1511.01863). Contrary to the understandable spin that these sorts of analyses attract, a review of their results suggests that they endorse the use of parametric assumptions-and random field theory-in the analysis of functional neuroimaging data. We briefly rehearse the advantages parametric analyses offer over nonparametric alternatives and then unpack the implications of (Eklund et al. []: arXiv 1511.01863) for parametric procedures. Hum Brain Mapp, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  19. Human error data collection analysis program undertaken since 1982 by Electricite de France with INPO

    International Nuclear Information System (INIS)

    Ghertman, F.; Dietz, P.

    1985-01-01

    The preoccupation for reducing in frequency and importance events which harm at various degrees the availability, the safety and the security of nuclear power plants lead Electricite de France, in cooperation with INPO (Institute of Nuclear Power Operations) to launch a Human Error Collection and Analysis Program. On account with the difficulties met to develop such a program, it has been decided to begin with a pilot data collection limited to a six months period (October 1982 to April 1983) and three nuclear power plants (three US units and two French units). This pilot data collection followed four steps: (1) elaboration of the collection methodology; (2) sensitization and related training of the power plant personnel; (3) data collection in the power plant; and (4) analysis of the data and results. Each of the steps are discussed in the paper

  20. Manufacturing error sensitivity analysis and optimal design method of cable-network antenna structures

    Science.gov (United States)

    Zong, Yali; Hu, Naigang; Duan, Baoyan; Yang, Guigeng; Cao, Hongjun; Xu, Wanye

    2016-03-01

    Inevitable manufacturing errors and inconsistency between assumed and actual boundary conditions can affect the shape precision and cable tensions of a cable-network antenna, and even result in failure of the structure in service. In this paper, an analytical sensitivity analysis method of the shape precision and cable tensions with respect to the parameters carrying uncertainty was studied. Based on the sensitivity analysis, an optimal design procedure was proposed to alleviate the effects of the parameters that carry uncertainty. The validity of the calculated sensitivities is examined by those computed by a finite difference method. Comparison with a traditional design method shows that the presented design procedure can remarkably reduce the influence of the uncertainties on the antenna performance. Moreover, the results suggest that especially slender front net cables, thick tension ties, relatively slender boundary cables and high tension level can improve the ability of cable-network antenna structures to resist the effects of the uncertainties on the antenna performance.

  1. An Analysis and Quantification Method of Human Errors of Soft Controls in Advanced MCRs

    International Nuclear Information System (INIS)

    Lee, Seung Jun; Kim, Jae Whan; Jang, Seung Cheol

    2011-01-01

    In this work, a method was proposed for quantifying human errors that may occur during operation executions using soft control. Soft controls of advanced main control rooms (MCRs) have totally different features from conventional controls, and thus they may have different human error modes and occurrence probabilities. It is important to define the human error modes and to quantify the error probability for evaluating the reliability of the system and preventing errors. This work suggests a modified K-HRA method for quantifying error probability

  2. Characterization and error analysis of an N×N unfolding procedure applied to filtered, photoelectric x-ray detector arrays. II. Error analysis and generalization

    Directory of Open Access Journals (Sweden)

    D. L. Fehl

    2010-12-01

    Full Text Available A five-channel, filtered-x-ray-detector (XRD array has been used to measure time-dependent, soft-x-ray flux emitted by z-pinch plasmas at the Z pulsed-power accelerator (Sandia National Laboratories, Albuquerque, New Mexico, USA. The preceding, companion paper [D. L. Fehl et al., Phys. Rev. ST Accel. Beams 13, 120402 (2010PRABFM1098-4402] describes an algorithm for spectral reconstructions (unfolds and spectrally integrated flux estimates from data obtained by this instrument. The unfolded spectrum S_{unfold}(E,t is based on (N=5 first-order B-splines (histograms in contiguous unfold bins j=1,…,N; the recovered x-ray flux F_{unfold}(t is estimated as ∫S_{unfold}(E,tdE, where E is x-ray energy and t is time. This paper adds two major improvements to the preceding unfold analysis: (a Error analysis.—Both data noise and response-function uncertainties are propagated into S_{unfold}(E,t and F_{unfold}(t. Noise factors ν are derived from simulations to quantify algorithm-induced changes in the noise-to-signal ratio (NSR for S_{unfold} in each unfold bin j and for F_{unfold} (ν≡NSR_{output}/NSR_{input}: for S_{unfold}, 1≲ν_{j}≲30, an outcome that is strongly spectrally dependent; for F_{unfold}, 0.6≲ν_{F}≲1, a result that is less spectrally sensitive and corroborated independently. For nominal z-pinch experiments, the combined uncertainty (noise and calibrations in F_{unfold}(t at peak is estimated to be ∼15%. (b Generalization of the unfold method.—Spectral sensitivities (called here passband functions are constructed for S_{unfold} and F_{unfold}. Predicting how the unfold algorithm reconstructs arbitrary spectra is thereby reduced to quadratures. These tools allow one to understand and quantitatively predict algorithmic distortions (including negative artifacts, to identify potentially troublesome spectra, and to design more useful response functions.

  3. Frequency and analysis of non-clinical errors made in radiology reports using the National Integrated Medical Imaging System voice recognition dictation software.

    Science.gov (United States)

    Motyer, R E; Liddy, S; Torreggiani, W C; Buckley, O

    2016-11-01

    Voice recognition (VR) dictation of radiology reports has become the mainstay of reporting in many institutions worldwide. Despite benefit, such software is not without limitations, and transcription errors have been widely reported. Evaluate the frequency and nature of non-clinical transcription error using VR dictation software. Retrospective audit of 378 finalised radiology reports. Errors were counted and categorised by significance, error type and sub-type. Data regarding imaging modality, report length and dictation time was collected. 67 (17.72 %) reports contained ≥1 errors, with 7 (1.85 %) containing 'significant' and 9 (2.38 %) containing 'very significant' errors. A total of 90 errors were identified from the 378 reports analysed, with 74 (82.22 %) classified as 'insignificant', 7 (7.78 %) as 'significant', 9 (10 %) as 'very significant'. 68 (75.56 %) errors were 'spelling and grammar', 20 (22.22 %) 'missense' and 2 (2.22 %) 'nonsense'. 'Punctuation' error was most common sub-type, accounting for 27 errors (30 %). Complex imaging modalities had higher error rates per report and sentence. Computed tomography contained 0.040 errors per sentence compared to plain film with 0.030. Longer reports had a higher error rate, with reports >25 sentences containing an average of 1.23 errors per report compared to 0-5 sentences containing 0.09. These findings highlight the limitations of VR dictation software. While most error was deemed insignificant, there were occurrences of error with potential to alter report interpretation and patient management. Longer reports and reports on more complex imaging had higher error rates and this should be taken into account by the reporting radiologist.

  4. Bayesian analysis of data and model error in rainfall-runoff hydrological models

    Science.gov (United States)

    Kavetski, D.; Franks, S. W.; Kuczera, G.

    2004-12-01

    A major unresolved issue in the identification and use of conceptual hydrologic models is realistic description of uncertainty in the data and model structure. In particular, hydrologic parameters often cannot be measured directly and must be inferred (calibrated) from observed forcing/response data (typically, rainfall and runoff). However, rainfall varies significantly in space and time, yet is often estimated from sparse gauge networks. Recent work showed that current calibration methods (e.g., standard least squares, multi-objective calibration, generalized likelihood uncertainty estimation) ignore forcing uncertainty and assume that the rainfall is known exactly. Consequently, they can yield strongly biased and misleading parameter estimates. This deficiency confounds attempts to reliably test model hypotheses, to generalize results across catchments (the regionalization problem) and to quantify predictive uncertainty when the hydrologic model is extrapolated. This paper continues the development of a Bayesian total error analysis (BATEA) methodology for the calibration and identification of hydrologic models, which explicitly incorporates the uncertainty in both the forcing and response data, and allows systematic model comparison based on residual model errors and formal Bayesian hypothesis testing (e.g., using Bayes factors). BATEA is based on explicit stochastic models for both forcing and response uncertainty, whereas current techniques focus solely on response errors. Hence, unlike existing methods, the BATEA parameter equations directly reflect the modeler's confidence in all the data. We compare several approaches to approximating the parameter distributions: a) full Markov Chain Monte Carlo methods and b) simplified approaches based on linear approximations. Studies using synthetic and real data from the US and Australia show that BATEA systematically reduces the parameter bias, leads to more meaningful model fits and allows model comparison taking

  5. Computer tomography, magnetic resonance imaging, and positron emission tomography or positron emission tomography/computer tomography for detection of metastatic lymph nodes in patients with ovarian cancer: A meta-analysis

    International Nuclear Information System (INIS)

    Yuan Ying; Gu Zhaoxiang; Tao Xiaofeng; Liu Shiyuan

    2012-01-01

    Objectives: To compare the diagnostic performances of computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET or PET/CT) for detection of metastatic lymph nodes in patients with ovarian cancer. Methods: Relevant studies were identified with MEDLINE and EMBASE from January 1990 to July 2010. We estimated the weighted summary sensitivities, specificities, OR (odds ratio), and summary receiver operating characteristic (sROC) curves of each imaging technique and conducted pair-wise comparisons using the two-sample Z-test. Meta-regression, subgroup analysis, and funnel plots were also performed to explain the between-study heterogeneity. Results: Eighteen eligible studies were included, with a total of 882 patients. PET or PET/CT was a more accurate modality (sensitivity, 73.2%; specificity, 96.7%; OR [odds ratio], 90.32). No significant difference was detected between CT (sensitivity, 42.6%; specificity, 95.0%; OR, 19.87) and MR imaging (sensitivity, 54.7%; specificity, 88.3%; OR, 12.38). Meta-regression analyses and subgroup analyses revealed no statistical difference. Funnel plots with marked asymmetry suggested a publication bias. Conclusion: FDG-PET or FDG-PET/CT is more accurate than CT and MR imaging in the detection of lymph node metastasis in patients with ovarian cancer.

  6. Errors Analysis of Students in Mathematics Department to Learn Plane Geometry

    Science.gov (United States)

    Mirna, M.

    2018-04-01

    This article describes the results of qualitative descriptive research that reveal the locations, types and causes of student error in answering the problem of plane geometry at the problem-solving level. Answers from 59 students on three test items informed that students showed errors ranging from understanding the concepts and principles of geometry itself to the error in applying it to problem solving. Their type of error consists of concept errors, principle errors and operational errors. The results of reflection with four subjects reveal the causes of the error are: 1) student learning motivation is very low, 2) in high school learning experience, geometry has been seen as unimportant, 3) the students' experience using their reasoning in solving the problem is very less, and 4) students' reasoning ability is still very low.

  7. Error Analysis in the Joint Event Location/Seismic Calibration Inverse Problem

    National Research Council Canada - National Science Library

    Rodi, William L

    2006-01-01

    This project is developing new mathematical and computational techniques for analyzing the uncertainty in seismic event locations, as induced by observational errors and errors in travel-time models...

  8. Analysis and compensation of synchronous measurement error for multi-channel laser interferometer

    International Nuclear Information System (INIS)

    Du, Shengwu; Hu, Jinchun; Zhu, Yu; Hu, Chuxiong

    2017-01-01

    Dual-frequency laser interferometer has been widely used in precision motion system as a displacement sensor, to achieve nanoscale positioning or synchronization accuracy. In a multi-channel laser interferometer synchronous measurement system, signal delays are different in the different channels, which will cause asynchronous measurement, and then lead to measurement error, synchronous measurement error (SME). Based on signal delay analysis of the measurement system, this paper presents a multi-channel SME framework for synchronous measurement, and establishes the model between SME and motion velocity. Further, a real-time compensation method for SME is proposed. This method has been verified in a self-developed laser interferometer signal processing board (SPB). The experiment result showed that, using this compensation method, at a motion velocity 0.89 m s −1 , the max SME between two measuring channels in the SPB is 1.1 nm. This method is more easily implemented and applied to engineering than the method of directly testing smaller signal delay. (paper)

  9. Symbol and Bit Error Rates Analysis of Hybrid PIM-CDMA

    Directory of Open Access Journals (Sweden)

    Ghassemlooy Z

    2005-01-01

    Full Text Available A hybrid pulse interval modulation code-division multiple-access (hPIM-CDMA scheme employing the strict optical orthogonal code (SOCC with unity and auto- and cross-correlation constraints for indoor optical wireless communications is proposed. In this paper, we analyse the symbol error rate (SER and bit error rate (BER of hPIM-CDMA. In the analysis, we consider multiple access interference (MAI, self-interference, and the hybrid nature of the hPIM-CDMA signal detection, which is based on the matched filter (MF. It is shown that the BER/SER performance can only be evaluated if the bit resolution conforms to the condition set by the number of consecutive false alarm pulses that might occur and be detected, so that one symbol being divided into two is unlikely to occur. Otherwise, the probability of SER and BER becomes extremely high and indeterminable. We show that for a large number of users, the BER improves when increasing the code weight . The results presented are compared with other modulation schemes.

  10. Analysis and compensation of synchronous measurement error for multi-channel laser interferometer

    Science.gov (United States)

    Du, Shengwu; Hu, Jinchun; Zhu, Yu; Hu, Chuxiong

    2017-05-01

    Dual-frequency laser interferometer has been widely used in precision motion system as a displacement sensor, to achieve nanoscale positioning or synchronization accuracy. In a multi-channel laser interferometer synchronous measurement system, signal delays are different in the different channels, which will cause asynchronous measurement, and then lead to measurement error, synchronous measurement error (SME). Based on signal delay analysis of the measurement system, this paper presents a multi-channel SME framework for synchronous measurement, and establishes the model between SME and motion velocity. Further, a real-time compensation method for SME is proposed. This method has been verified in a self-developed laser interferometer signal processing board (SPB). The experiment result showed that, using this compensation method, at a motion velocity 0.89 m s-1, the max SME between two measuring channels in the SPB is 1.1 nm. This method is more easily implemented and applied to engineering than the method of directly testing smaller signal delay.

  11. Bayesian linear regression with skew-symmetric error distributions with applications to survival analysis

    KAUST Repository

    Rubio, Francisco J.

    2016-02-09

    We study Bayesian linear regression models with skew-symmetric scale mixtures of normal error distributions. These kinds of models can be used to capture departures from the usual assumption of normality of the errors in terms of heavy tails and asymmetry. We propose a general noninformative prior structure for these regression models and show that the corresponding posterior distribution is proper under mild conditions. We extend these propriety results to cases where the response variables are censored. The latter scenario is of interest in the context of accelerated failure time models, which are relevant in survival analysis. We present a simulation study that demonstrates good frequentist properties of the posterior credible intervals associated with the proposed priors. This study also sheds some light on the trade-off between increased model flexibility and the risk of over-fitting. We illustrate the performance of the proposed models with real data. Although we focus on models with univariate response variables, we also present some extensions to the multivariate case in the Supporting Information.

  12. Efficient thermal error prediction in a machine tool using finite element analysis

    International Nuclear Information System (INIS)

    Mian, Naeem S; Fletcher, Simon; Longstaff, Andrew P; Myers, Alan

    2011-01-01

    Thermally induced errors have a major significance on the positional accuracy of a machine tool. Heat generated during the machining process produces thermal gradients that flow through the machine structure causing linear and nonlinear thermal expansions and distortions of associated complex discrete structures, producing deformations that adversely affect structural stability. The heat passes through structural linkages and mechanical joints where interfacial parameters such as the roughness and form of the contacting surfaces affect the thermal resistance and thus the heat transfer coefficients. This paper presents a novel offline technique using finite element analysis (FEA) to simulate the effects of the major internal heat sources such as bearings, motors and belt drives of a small vertical milling machine (VMC) and the effects of ambient temperature pockets that build up during the machine operation. Simplified models of the machine have been created offline using FEA software and evaluated experimental results applied for offline thermal behaviour simulation of the full machine structure. The FEA simulated results are in close agreement with the experimental results ranging from 65% to 90% for a variety of testing regimes and revealed a maximum error range of 70 µm reduced to less than 10 µm

  13. The error analysis of coke moisture measured by neutron moisture gauge

    International Nuclear Information System (INIS)

    Tian Huixing

    1995-01-01

    The error of coke moisture measured by neutron method in the iron and steel industry is analyzed. The errors are caused by inaccurate sampling location in the calibration procedure on site. By comparison, the instrument error and the statistical fluctuation error are smaller. So the sampling proportion should be increased as large as possible in the calibration procedure on site, and a satisfied calibration effect can be obtained on a suitable size hopper

  14. Review of U.S. Army Unmanned Aerial Systems Accident Reports: Analysis of Human Error Contributions

    Science.gov (United States)

    2018-03-20

    within report documents. The information presented was obtained through a request to use the U.S. Army Combat Readiness Center’s Risk Management ...controlled flight into terrain (13 accidents), fueling errors by improper techniques (7 accidents), and a variety of maintenance errors (10 accidents). The...and 9 of the 10 maintenance accidents. Table 4. Frequencies Based on Source of Human Error Human error source Presence Poor Planning

  15. Height-Error Analysis for the FAA-Air Force Replacement Radar Program (FARR)

    Science.gov (United States)

    1991-08-01

    7719 Figure 1-7 CLIMATOLOGY ERRORS BY MONWTH PERCENT FREQUENCY TABLE OF ERROR BY MONTH ERROR MONTH Col Pc IJAl IFEB )MA IA R IAY JJ’N IJUL JAUG (SEP...MONTH Col Pct IJAN IFEB IMPJ JAPR 1 MM IJUN IJUL JAUG ISEP J--T IN~ IDEC I Total ----- -- - - --------------------------.. . -.. 4...MONTH ERROR MONTH Col Pct IJAN IFEB IM4AR IAPR IMAY jJum IJU JAUG ISEP JOCT IN JDEC I Total . .- 4

  16. Analysis of the “naming game” with learning errors in communications

    OpenAIRE

    Yang Lou; Guanrong Chen

    2015-01-01

    Naming game simulates the process of naming an objective by a population of agents organized in a certain communication network. By pair-wise iterative interactions, the population reaches consensus asymptotically. We study naming game with communication errors during pair-wise conversations, with error rates in a uniform probability distribution. First, a model of naming game with learning errors in communications (NGLE) is proposed. Then, a strategy for agents to prevent learning errors is ...

  17. Two-dimensional errors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

  18. Analysis of liquid medication dose errors made by patients and caregivers using alternative measuring devices.

    Science.gov (United States)

    Ryu, Gyeong Suk; Lee, Yu Jeung

    2012-01-01

    Patients use several types of devices to measure liquid medication. Using a criterion ranging from a 10% to 40% variation from a target 5 mL for a teaspoon dose, previous studies have found that a considerable proportion of patients or caregivers make errors when dosing liquid medication with measuring devices. To determine the rate and magnitude of liquid medication dose errors that occur with patient/caregiver use of various measuring devices in a community pharmacy. Liquid medication measurements by patients or caregivers were observed in a convenience sample of community pharmacy patrons in Korea during a 2-week period in March 2011. Participants included all patients or caregivers (N = 300) who came to the pharmacy to buy over-the-counter liquid medication or to have a liquid medication prescription filled during the study period. The participants were instructed by an investigator who was also a pharmacist to select their preferred measuring devices from 6 alternatives (etched-calibration dosing cup, printed-calibration dosing cup, dosing spoon, syringe, dispensing bottle, or spoon with a bottle adapter) and measure a 5 mL dose of Coben (chlorpheniramine maleate/phenylephrine HCl, Daewoo Pharm. Co., Ltd) syrup using the device of their choice. The investigator used an ISOLAB graduated cylinder (Germany, blue grad, 10 mL) to measure the amount of syrup dispensed by the study participants. Participant characteristics were recorded including gender, age, education level, and relationship to the person for whom the medication was intended. Of the 300 participants, 257 (85.7%) were female; 286 (95.3%) had at least a high school education; and 282 (94.0%) were caregivers (parent or grandparent) for the patient. The mean (SD) measured dose was 4.949 (0.378) mL for the 300 participants. In analysis of variance of the 6 measuring devices, the greatest difference from the 5 mL target was a mean 5.552 mL for 17 subjects who used the regular (etched) dosing cup and 4

  19. Analysis of operator splitting errors for near-limit flame simulations

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Zhen; Zhou, Hua [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Li, Shan [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); School of Aerospace Engineering, Tsinghua University, Beijing 100084 (China); Ren, Zhuyin, E-mail: zhuyinren@tsinghua.edu.cn [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); School of Aerospace Engineering, Tsinghua University, Beijing 100084 (China); Lu, Tianfeng [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269-3139 (United States); Law, Chung K. [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2017-04-15

    High-fidelity simulations of ignition, extinction and oscillatory combustion processes are of practical interest in a broad range of combustion applications. Splitting schemes, widely employed in reactive flow simulations, could fail for stiff reaction–diffusion systems exhibiting near-limit flame phenomena. The present work first employs a model perfectly stirred reactor (PSR) problem with an Arrhenius reaction term and a linear mixing term to study the effects of splitting errors on the near-limit combustion phenomena. Analysis shows that the errors induced by decoupling of the fractional steps may result in unphysical extinction or ignition. The analysis is then extended to the prediction of ignition, extinction and oscillatory combustion in unsteady PSRs of various fuel/air mixtures with a 9-species detailed mechanism for hydrogen oxidation and an 88-species skeletal mechanism for n-heptane oxidation, together with a Jacobian-based analysis for the time scales. The tested schemes include the Strang splitting, the balanced splitting, and a newly developed semi-implicit midpoint method. Results show that the semi-implicit midpoint method can accurately reproduce the dynamics of the near-limit flame phenomena and it is second-order accurate over a wide range of time step size. For the extinction and ignition processes, both the balanced splitting and midpoint method can yield accurate predictions, whereas the Strang splitting can lead to significant shifts on the ignition/extinction processes or even unphysical results. With an enriched H radical source in the inflow stream, a delay of the ignition process and the deviation on the equilibrium temperature are observed for the Strang splitting. On the contrary, the midpoint method that solves reaction and diffusion together matches the fully implicit accurate solution. The balanced splitting predicts the temperature rise correctly but with an over-predicted peak. For the sustainable and decaying oscillatory

  20. An Analysis of Lexical Errors of Korean Language Learners: Some American College Learners' Case

    Science.gov (United States)

    Kang, Manjin

    2014-01-01

    There has been a huge amount of research on errors of language learners. However, most of them have focused on syntactic errors and those about lexical errors are not found easily despite the importance of lexical learning for the language learners. The case is even rarer for Korean language. In line with this background, this study was designed…

  1. Human Error Analysis in a Permit to Work System: A Case Study in a Chemical Plant

    Directory of Open Access Journals (Sweden)

    Mehdi Jahangiri

    2016-03-01

    Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

  2. Analysis of irregular opacities of silicosis using computed tomography

    International Nuclear Information System (INIS)

    Maeda, Atsushi; Shida, Hisao; Chiyotani, Keizo; Saito, Kenichi; Mishina, Michihito

    1983-01-01

    Classification in used to codify Chest CT images of abnormalities of the lung in a simple reproducible manner. Simbols to record CT features of importance are listed. We applied CT to 92 cases of silicosis and roentgenological analysis was performed. Bullae, honeycombing, cavity, emphysema, pleural thickning and calcification were more clearly demonstrated in CT images than routine chest roentgenograms. Irregular opacities were considered to be a combined profusion of small round and streak or strand. (author)

  3. Sources of Error and the Statistical Formulation of M S: m b Seismic Event Screening Analysis

    Science.gov (United States)

    Anderson, D. N.; Patton, H. J.; Taylor, S. R.; Bonner, J. L.; Selby, N. D.

    2014-03-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT), a global ban on nuclear explosions, is currently in a ratification phase. Under the CTBT, an International Monitoring System (IMS) of seismic, hydroacoustic, infrasonic and radionuclide sensors is operational, and the data from the IMS is analysed by the International Data Centre (IDC). The IDC provides CTBT signatories basic seismic event parameters and a screening analysis indicating whether an event exhibits explosion characteristics (for example, shallow depth). An important component of the screening analysis is a statistical test of the null hypothesis H 0: explosion characteristics using empirical measurements of seismic energy (magnitudes). The established magnitude used for event size is the body-wave magnitude (denoted m b) computed from the initial segment of a seismic waveform. IDC screening analysis is applied to events with m b greater than 3.5. The Rayleigh wave magnitude (denoted M S) is a measure of later arriving surface wave energy. Magnitudes are measurements of seismic energy that include adjustments (physical correction model) for path and distance effects between event and station. Relative to m b, earthquakes generally have a larger M S magnitude than explosions. This article proposes a hypothesis test (screening analysis) using M S and m b that expressly accounts for physical correction model inadequacy in the standard error of the test statistic. With this hypothesis test formulation, the 2009 Democratic Peoples Republic of Korea announced nuclear weapon test fails to reject the null hypothesis H 0: explosion characteristics.

  4. An SEU analysis approach for error propagation in digital VLSI CMOS ASICs

    International Nuclear Information System (INIS)

    Baze, M.P.; Bartholet, W.G.; Dao, T.A.; Buchner, S.

    1995-01-01

    A critical issue in the development of ASIC designs is the ability to achieve first pass fabrication success. Unsuccessful fabrication runs have serious impact on ASIC costs and schedules. The ability to predict an ASICs radiation response prior to fabrication is therefore a key issue when designing ASICs for military and aerospace systems. This paper describes an analysis approach for calculating static bit error propagation in synchronous VLSI CMOS circuits developed as an aid for predicting the SEU response of ASIC's. The technique is intended for eventual application as an ASIC development simulation tool which can be used by circuit design engineers for performance evaluation during the pre-fabrication design process in much the same way that logic and timing simulators are used

  5. Ergodic Capacity Analysis of Free-Space Optical Links with Nonzero Boresight Pointing Errors

    KAUST Repository

    Ansari, Imran Shafique

    2015-04-01

    A unified capacity analysis of a free-space optical (FSO) link that accounts for nonzero boresight pointing errors and both types of detection techniques (i.e. intensity modulation/ direct detection as well as heterodyne detection) is addressed in this work. More specifically, an exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system is presented in terms of well-known elementary functions. Capitalizing on these new moments expressions, we present approximate and simple closedform results for the ergodic capacity at high and low SNR regimes. All the presented results are verified via computer-based Monte-Carlo simulations.

  6. Bit Error Rate Analysis for MC-CDMA Systems in Nakagami- Fading Channels

    Directory of Open Access Journals (Sweden)

    Li Zexian

    2004-01-01

    Full Text Available Multicarrier code division multiple access (MC-CDMA is a promising technique that combines orthogonal frequency division multiplexing (OFDM with CDMA. In this paper, based on an alternative expression for the -function, characteristic function and Gaussian approximation, we present a new practical technique for determining the bit error rate (BER of multiuser MC-CDMA systems in frequency-selective Nakagami- fading channels. The results are applicable to systems employing coherent demodulation with maximal ratio combining (MRC or equal gain combining (EGC. The analysis assumes that different subcarriers experience independent fading channels, which are not necessarily identically distributed. The final average BER is expressed in the form of a single finite range integral and an integrand composed of tabulated functions which can be easily computed numerically. The accuracy of the proposed approach is demonstrated with computer simulations.

  7. Problems of accuracy and sources of error in trace analysis of elements

    International Nuclear Information System (INIS)

    Porat, Ze'ev.

    1995-07-01

    The technological developments in the field of analytical chemistry in recent years facilitates trace analysis of materials in sub-ppb levels. This provides important information regarding the presence of various trace elements in the human body, in drinking water and in the environment. However, it also exposes the measurements to more severe problems of contamination and inaccuracy due to the high sensitivity of the analytical methods. The sources of error are numerous and can be included in three main groups: (a) impurities of various sources; (b) loss of material during sample processing; (c) problems of calibration and interference. These difficulties are discussed here in detail, together with some practical solutions and examples.(authors) 8 figs., 2 tabs., 18 refs.,

  8. Problems of accuracy and sources of error in trace analysis of elements

    Energy Technology Data Exchange (ETDEWEB)

    Porat, Ze` ev

    1995-07-01

    The technological developments in the field of analytical chemistry in recent years facilitates trace analysis of materials in sub-ppb levels. This provides important information regarding the presence of various trace elements in the human body, in drinking water and in the environment. However, it also exposes the measurements to more severe problems of contamination and inaccuracy due to the high sensitivity of the analytical methods. The sources of error are numerous and can be included in three main groups: (a) impurities of various sources; (b) loss of material during sample processing; (c) problems of calibration and interference. These difficulties are discussed here in detail, together with some practical solutions and examples.(authors) 8 figs., 2 tabs., 18 refs.,.

  9. X-ray computed tomography datasets for forensic analysis of vertebrate fossils

    Science.gov (United States)

    Rowe, Timothy B.; Luo, Zhe-Xi; Ketcham, Richard A.; Maisano, Jessica A.; Colbert, Matthew W.

    2016-01-01

    We describe X-ray computed tomography (CT) datasets from three specimens recovered from Early Cretaceous lakebeds of China that illustrate the forensic interpretation of CT imagery for paleontology. Fossil vertebrates from thinly bedded sediments often shatter upon discovery and are commonly repaired as amalgamated mosaics grouted to a solid backing slab of rock or plaster. Such methods are prone to inadvertent error and willful forgery, and once required potentially destructive methods to identify mistakes in reconstruction. CT is an efficient, nondestructive alternative that can disclose many clues about how a specimen was handled and repaired. These annotated datasets illustrate the power of CT in documenting specimen integrity and are intended as a reference in applying CT more broadly to evaluating the authenticity of comparable fossils. PMID:27272251

  10. Positron-emission tomography as a new direction in radiation medicine development (scientometric analysis)

    International Nuclear Information System (INIS)

    Artamonova, N.O.; Masyich, O.V.; Pavlyichenko, Yu.V.; Shepeljev, A.G.; Kuryilo, Yu.P.; Ponomarenko, T.O.

    2009-01-01

    The contemporary state and prospects of positron-emission tomography (PET) application in diagnosis of cancer diseases are investigated. The comparative analysis of the image of the topical field in Medline and INIS allowed to allocate the zones of intensive investigation of PET efficacy at cancer diseases, investigations of the brain, lungs, heart as well as to establish the peculiarities of the search depending on the features of their search interfaces

  11. Computer-tomography and its use in failure analysis; Computertomographie und deren Anwendung in der Schadensanalytik

    Energy Technology Data Exchange (ETDEWEB)

    Panzenboeck, Michael; Freitag, Caroline [Montanuniv. Leoben (Austria). Dept. Metallkunde und Werkstoffpruefung; Borchert, Marlies [Materials Center Leoben (Austria)

    2017-04-15

    In the last fifteen years computer-tomography has proven to be a valuable aid in the fields of medicine, materials technology and forensics. Nowadays it is hard to image non-destructive testing being carried out without its use. This article serves to demonstrate the power of the technique within the field of failure analysis with reference to two chosen case studies. The first case concerns the failure of magnetic valves, the second case focusses on the failure of corrosion resistant screws.

  12. Positron Emission Tomography in Prostate Cancer: Summary of Systematic Reviews and Meta-Analysis

    OpenAIRE

    Jadvar, Hossein

    2015-01-01

    Prostate cancer is a prevalent public health problem worldwide. Over the past decade, there has been tremendous research activity in the potential use of positron emission tomography with a number of radiotracers targeted to various biological aspects of this complex tumor. Systematic reviews and meta-analysis are important contributions to the relevant literature that summarize the evidence while reducing the effect of various sources of bias in the published data. The accumulation of releva...

  13. Hardware Design of Tuber Electrical Resistance Tomography System Based on the Soil Impedance Test and Analysis

    OpenAIRE

    Liu Shuyi; Deng Xiang; Jiang Zili; Tang Yu

    2016-01-01

    The hardware design of tuber electrical resistance tomography (TERT) system is one of the key research problems of TERT data acquisition system. The TERT system can be applied to the tuber growth process monitoring in agriculture, i.e., the TERT data acquisition system can realize the real imaging of tuber plants in soil. In TERT system, the imaging tuber and soil multiphase medium is quite complexity. So, the impedance test and analysis of soil multiphase medium is very important to the desi...

  14. Analysis and Compensation for Gear Accuracy with Setting Error in Form Grinding

    Directory of Open Access Journals (Sweden)

    Chenggang Fang

    2015-01-01

    Full Text Available In the process of form grinding, gear setting error was the main factor that influenced the form grinding accuracy; we proposed an effective method to improve form grinding accuracy that corrected the error by controlling the machine operations. Based on establishing the geometry model of form grinding and representing the gear setting errors as homogeneous coordinate, tooth mathematic model was obtained and simplified under the gear setting error. Then, according to the gear standard of ISO1328-1: 1997 and the ANSI/AGMA 2015-1-A01: 2002, the relationship was investigated by changing the gear setting errors with respect to tooth profile deviation, helix deviation, and cumulative pitch deviation, respectively, under the condition of gear eccentricity error, gear inclination error, and gear resultant error. An error compensation method was proposed based on solving sensitivity coefficient matrix of setting error in a five-axis CNC form grinding machine; simulation and experimental results demonstrated that the method can effectively correct the gear setting error, as well as further improving the forming grinding accuracy.

  15. Prepopulated radiology report templates: a prospective analysis of error rate and turnaround time.

    Science.gov (United States)

    Hawkins, C M; Hall, S; Hardin, J; Salisbury, S; Towbin, A J

    2012-08-01

    Current speech recognition software allows exam-specific standard reports to be prepopulated into the dictation field based on the radiology information system procedure code. While it is thought that prepopulating reports can decrease the time required to dictate a study and the overall number of errors in the final report, this hypothesis has not been studied in a clinical setting. A prospective study was performed. During the first week, radiologists dictated all studies using prepopulated standard reports. During the second week, all studies were dictated after prepopulated reports had been disabled. Final radiology reports were evaluated for 11 different types of errors. Each error within a report was classified individually. The median time required to dictate an exam was compared between the 2 weeks. There were 12,387 reports dictated during the study, of which, 1,173 randomly distributed reports were analyzed for errors. There was no difference in the number of errors per report between the 2 weeks; however, radiologists overwhelmingly preferred using a standard report both weeks. Grammatical errors were by far the most common error type, followed by missense errors and errors of omission. There was no significant difference in the median dictation time when comparing studies performed each week. The use of prepopulated reports does not alone affect the error rate or dictation time of radiology reports. While it is a useful feature for radiologists, it must be coupled with other strategies in order to decrease errors.

  16. Phase correction and error estimation in InSAR time series analysis

    Science.gov (United States)

    Zhang, Y.; Fattahi, H.; Amelung, F.

    2017-12-01

    During the last decade several InSAR time series approaches have been developed in response to the non-idea acquisition strategy of SAR satellites, such as large spatial and temporal baseline with non-regular acquisitions. The small baseline tubes and regular acquisitions of new SAR satellites such as Sentinel-1 allows us to form fully connected networks of interferograms and simplifies the time series analysis into a weighted least square inversion of an over-determined system. Such robust inversion allows us to focus more on the understanding of different components in InSAR time-series and its uncertainties. We present an open-source python-based package for InSAR time series analysis, called PySAR (https://yunjunz.github.io/PySAR/), with unique functionalities for obtaining unbiased ground displacement time-series, geometrical and atmospheric correction of InSAR data and quantifying the InSAR uncertainty. Our implemented strategy contains several features including: 1) improved spatial coverage using coherence-based network of interferograms, 2) unwrapping error correction using phase closure or bridging, 3) tropospheric delay correction using weather models and empirical approaches, 4) DEM error correction, 5) optimal selection of reference date and automatic outlier detection, 6) InSAR uncertainty due to the residual tropospheric delay, decorrelation and residual DEM error, and 7) variance-covariance matrix of final products for geodetic inversion. We demonstrate the performance using SAR datasets acquired by Cosmo-Skymed and TerraSAR-X, Sentinel-1 and ALOS/ALOS-2, with application on the highly non-linear volcanic deformation in Japan and Ecuador (figure 1). Our result shows precursory deformation before the 2015 eruptions of Cotopaxi volcano, with a maximum uplift of 3.4 cm on the western flank (fig. 1b), with a standard deviation of 0.9 cm (fig. 1a), supporting the finding by Morales-Rivera et al. (2017, GRL); and a post-eruptive subsidence on the same

  17. Practical Insights from Initial Studies Related to Human Error Analysis Project (HEAP)

    International Nuclear Information System (INIS)

    Follesoe, Knut; Kaarstad, Magnhild; Droeivoldsmo, Asgeir; Hollnagel, Erik; Kirwan; Barry

    1996-01-01

    This report presents practical insights made from an analysis of the three initial studies in the Human Error Analysis Project (HEAP), and the first study in the US NRC Staffing Project. These practical insights relate to our understanding of diagnosis in Nuclear Power Plant (NPP) emergency scenarios and, in particular, the factors that influence whether a diagnosis will succeed or fail. The insights reported here focus on three inter-related areas: (1) the diagnostic strategies and styles that have been observed in single operator and team-based studies; (2) the qualitative aspects of the key operator support systems, namely VDU interfaces, alarms, training and procedures, that have affected the outcome of diagnosis; and (3) the overall success rates of diagnosis and the error types that have been observed in the various studies. With respect to diagnosis, certain patterns have emerged from the various studies, depending on whether operators were alone or in teams, and on their familiarity with the process. Some aspects of the interface and alarm systems were found to contribute to diagnostic failures while others supported performance and recovery. Similar results were found for training and experience. Furthermore, the availability of procedures did not preclude the need for some diagnosis. With respect to HRA and PSA, it was possible to record the failure types seen in the studies, and in some cases to give crude estimates of the failure likelihood for certain scenarios. Although these insights are interim in nature, they do show the type of information that can be derived from these studies. More importantly, they clarify aspects of our understanding of diagnosis in NPP emergencies, including implications for risk assessment, operator support systems development, and for research into diagnosis in a broader range of fields than the nuclear power industry. (author)

  18. Output Error Analysis of Planar 2-DOF Five-bar Mechanism

    Science.gov (United States)

    Niu, Kejia; Wang, Jun; Ting, Kwun-Lon; Tao, Fen; Cheng, Qunchao; Wang, Quan; Zhang, Kaiyang

    2018-03-01

    Aiming at the mechanism error caused by clearance of planar 2-DOF Five-bar motion pair, the method of equivalent joint clearance of kinematic pair to virtual link is applied. The structural error model of revolute joint clearance is established based on the N-bar rotation laws and the concept of joint rotation space, The influence of the clearance of the moving pair is studied on the output error of the mechanis. and the calculation method and basis of the maximum error are given. The error rotation space of the mechanism under the influence of joint clearance is obtained. The results show that this method can accurately calculate the joint space error rotation space, which provides a new way to analyze the planar parallel mechanism error caused by joint space.

  19. Data on analysis of coronary atherosclerosis on computed tomography and 18F-sodium fluoride positron emission tomography

    Directory of Open Access Journals (Sweden)

    Toshiro Kitagawa

    2017-08-01

    Full Text Available This article contains the data showing illustrative examples of plaque classification on coronary computed tomography angiography (CCTA and measurement of 18F-sodium fluoride (18F-NaF uptake in coronary atherosclerotic lesions on positron emission tomography (PET. We divided the lesions into one of three plaque types on CCTA (calcified plaque, non-calcified plaque, partially calcified plaque. Focal 18F-NaF uptake of each lesion was quantified using maximum tissue-to-background ratio. This article also provides a representative case with a non-calcified coronary plaque detected on CCTA and identified on 18F-NaF PET/non-contrast computed tomography based on a location of a vessel branch as a landmark. These complement the data reported by Kitagawa et al. (2017 [1].

  20. Analysis of the effects of Eye-Tracker performance on the pulse positioning errors during refractive surgery

    Directory of Open Access Journals (Sweden)

    Samuel Arba-Mosquera

    2012-01-01

    Conclusions: The proposed model can be used for comparison of laser systems used for ablation processes. Due to the pseudo-random nature of eye movements, positioning errors of single pulses are much larger than observed decentrations in the clinical settings. There is no single parameter that ‘alone’ minimizes the positioning error. It is the optimal combination of the several parameters that minimizes the error. The results of this analysis are important to understand the limitations of correcting very irregular ablation patterns.