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.
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.
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.
Error Analysis in Mathematics. Technical Report #1012
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…
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
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
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)
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...
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.
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
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
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
Numeracy, Literacy and Newman's Error Analysis
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…
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)
Error analysis of stochastic gradient descent ranking.
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.
Error begat error: design error analysis and prevention in social infrastructure projects.
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.
Error Analysis of Determining Airplane Location by Global Positioning System
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.
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.
[Analysis of intrusion errors in free recall].
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.
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.
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
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.
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
Asteroid orbital error analysis: Theory and application
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).
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.)
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.
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.
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.
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
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.
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 ...
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
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
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
Sensitivity analysis of periodic errors in heterodyne interferometry
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.
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
Attitude Determination Error Analysis System (ADEAS) mathematical specifications document
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.
Comprehensive analysis of a medication dosing error related to CPOE.
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.
Data Analysis & Statistical Methods for Command File Errors
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.
Grinding Method and Error Analysis of Eccentric Shaft Parts
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.
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...
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)
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.
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.
QUALITATIVE DATA AND ERROR MEASUREMENT IN INPUT-OUTPUT-ANALYSIS
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
Understanding Teamwork in Trauma Resuscitation through Analysis of Team Errors
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…
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
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
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
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
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 ...
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.
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.
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.
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...
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.
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)
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
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...
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
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.
Accommodating error analysis in comparison and clustering of molecular fingerprints.
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 ...
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.)
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.
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)
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)
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.)
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.)
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.
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
Error performance analysis in downlink cellular networks with interference management
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.
Error Analysis for Fourier Methods for Option Pricing
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.
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.
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.
Error analysis of mathematical problems on TIMSS: A case of Indonesian secondary students
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.
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.
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
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
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)
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:.
Accommodating error analysis in comparison and clustering of molecular fingerprints.
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.
Error-rate performance analysis of opportunistic regenerative relaying
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.
Kitchen Physics: Lessons in Fluid Pressure and Error Analysis
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.
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
The error performance analysis over cyclic redundancy check codes
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.
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.
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
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
Analysis of error-correction constraints in an optical disk
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.
Analysis of the "naming game" with learning errors in communications.
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.
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
An error taxonomy system for analysis of haemodialysis incidents.
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.
Generalization error analysis: deep convolutional neural network in mammography
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.
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 ...
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.
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
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.
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.
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.
ERM model analysis for adaptation to hydrological model errors
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.
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.
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
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
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
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
Error Analysis for Fourier Methods for Option Pricing
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
Error Analysis of Inertial Navigation Systems Using Test Algorithms
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 ...
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.)
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
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.
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
Error Analysis of Brailled Instructional Materials Produced by Public School Personnel in Texas
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,…
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.)
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.
Error analysis in predictive modelling demonstrated on mould data.
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.
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
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)
Analysis and improvement of gas turbine blade temperature measurement error
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.
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
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
Human error in strabismus surgery: Quantification with a sensitivity analysis
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
Human error in strabismus surgery : Quantification with a sensitivity analysis
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
Linguistic Error Analysis on Students' Thesis Proposals
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…
Reading and Spelling Error Analysis of Native Arabic Dyslexic Readers
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…
Analysis of Students' Error in Learning of Quadratic Equations
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…
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.)
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.
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)
Error analysis of terrestrial laser scanning data by means of spherical statistics and 3D graphs.
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.
Spectral Analysis of Forecast Error Investigated with an Observing System Simulation Experiment
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.
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
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
Error analysis of pupils in calculating with fractions
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 ...
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.
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.
Slow Learner Errors Analysis in Solving Fractions Problems in Inclusive Junior High School Class
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.
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.)
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
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.
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.
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...
Analysis of Student Errors on Division of Fractions
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.
Error Probability Analysis of Hardware Impaired Systems with Asymmetric Transmission
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
Error Probability Analysis of Hardware Impaired Systems with Asymmetric Transmission
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
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.
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
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
Stochastic and sensitivity analysis of shape error of inflatable antenna reflectors
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.
Contribution of Error Analysis to Foreign Language Teaching
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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.
Study on analysis from sources of error for Airborne LIDAR
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.
Hebbian errors in learning: an analysis using the Oja model.
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.
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
Analysis of measured data of human body based on error correcting frequency
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.
Boundary error analysis and categorization in the TRECVID news story segmentation task
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
An Analysis of College Students' Attitudes towards Error Correction in EFL Context
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…
Analysis of Errors and Misconceptions in the Learning of Calculus by Undergraduate Students
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…
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)
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.
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)
Analysis technique for controlling system wavefront error with active/adaptive optics
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.
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.
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
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
Accounting for covariate measurement error in a Cox model analysis of recurrence of depression.
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.
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.
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.
Quality of IT service delivery — Analysis and framework for human error prevention
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.
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.
Error and Uncertainty Analysis for Ecological Modeling and Simulation
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
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...
Quality of IT service delivery — Analysis and framework for human error prevention
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
Ergodic Capacity Analysis of Free-Space Optical Links with Nonzero Boresight Pointing Errors
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
Diffraction analysis of sidelobe characteristics of optical elements with ripple error
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.
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.
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
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)
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.
Kinematic Analysis of Speech Sound Sequencing Errors Induced by Delayed Auditory Feedback.
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.
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.
Decimal Fraction Arithmetic: Logical Error Analysis and Its Validation.
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…
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.)
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)
A theoretical basis for the analysis of multiversion software subject to coincident errors
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.
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.
Covariance Analysis Tool (G-CAT) for Computing Ascent, Descent, and Landing Errors
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
Disasters of endoscopic surgery and how to avoid them: error analysis.
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.
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
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
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
Thermal error analysis and compensation for digital image/volume correlation
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.
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.
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.
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.
A stochastic dynamic model for human error analysis in nuclear power plants
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.
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)
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.
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.
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)
Wavefront-error evaluation by mathematical analysis of experimental Foucault-test data
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.
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.
Study on Network Error Analysis and Locating based on Integrated Information Decision System
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.
Component Analysis of Errors on PERSIANN Precipitation Estimates over Urmia Lake Basin, IRAN
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.
Detecting medication errors in the New Zealand pharmacovigilance database: a retrospective analysis.
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
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
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
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)
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.
Optical system error analysis and calibration method of high-accuracy star trackers.
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.
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.
Outcomes of a Failure Mode and Effects Analysis for medication errors in pediatric anesthesia.
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.
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.
LEARNING FROM MISTAKES Error Analysis in the English Speech of Indonesian Tertiary Students
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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.
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.
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)
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.
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.
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.
Statistical analysis with measurement error or misclassification strategy, method and application
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...
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.
A Posteriori Error Analysis of Stochastic Differential Equations Using Polynomial Chaos Expansions
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.
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.
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
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.
Analysis on optical heterodyne frequency error of full-field heterodyne interferometer
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.
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.)
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.
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
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...
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
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.
Error analysis of the crystal orientations obtained by the dictionary approach to EBSD indexing.
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.
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.
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
Calculating potential error in sodium MRI with respect to the analysis of small objects.
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.
An analysis of error patterns in children's backward digit recall in noise
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
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
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.
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
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...
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.
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.
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.
Error Ratio Analysis: Alternate Mathematics Assessment for General and Special Educators.
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…
Diction and Expression in Error Analysis Can Enhance Academic Writing of L2 University Students
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…
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 ...
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
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, ...
Advanced GIS Exercise: Performing Error Analysis in ArcGIS ModelBuilder
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,…
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
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.
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)
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.
Analysis of Statistical Methods and Errors in the Articles Published in the Korean Journal of Pain
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
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.
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
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
On the BER and capacity analysis of MIMO MRC systems with channel estimation error
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.
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.
Doctors' duty to disclose error: a deontological or Kantian ethical analysis.
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.
Error-correction coding and decoding bounds, codes, decoders, analysis and applications
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...
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)
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
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.
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.
Error Analysis Of Students Working About Word Problem Of Linear Program With NEA Procedure
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.
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.
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
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)
Covariate measurement error correction methods in mediation analysis with failure time data.
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.
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
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.
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...
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...
On Gait Analysis Estimation Errors Using Force Sensors on a Smart Rollator.
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.
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.
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...
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
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.
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)
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)
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.
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.
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)
Inclusive bit error rate analysis for coherent optical code-division multiple-access system
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.
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
Catching errors with patient-specific pretreatment machine log file analysis.
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.
Measurements and their uncertainties a practical guide to modern error analysis
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....
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.
Application of human error theory in case analysis of wrong procedures.
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.
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)
An Analysis of Ripple and Error Fields Induced by a Blanket in the CFETR
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)
Error Analysis and Calibration Method of a Multiple Field-of-View Navigation System
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...
Error Analysis of Explicit Partitioned Runge–Kutta Schemes for Conservation Laws
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.
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
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
Error Analysis of Explicit Partitioned Runge–Kutta Schemes for Conservation Laws
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.
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.
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
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
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.
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).
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)
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.)
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)
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)
A Preliminary ZEUS Lightning Location Error Analysis Using a Modified Retrieval Theory
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."
Analysis of S-box in Image Encryption Using Root Mean Square Error Method
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
Error analysis of filtering operations in pixel-duplicated images of diabetic retinopathy
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.
BEATBOX v1.0: Background Error Analysis Testbed with Box Models
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.
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.
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.
Error analysis of satellite attitude determination using a vision-based approach
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).
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
Residents' surgical performance during the laboratory years: an analysis of rule-based errors.
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
High‐resolution trench photomosaics from image‐based modeling: Workflow and error analysis
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.
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...
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.
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)
Error Analysis System for Spacecraft Navigation Using the Global Positioning System (GPS)
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
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
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.
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
English word frequency and recognition in bilinguals: Inter-corpus comparison and error analysis.
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.
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.
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
Fractional Order Differentiation by Integration and Error Analysis in Noisy Environment
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.
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
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
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
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.
Error analysis of motion correction method for laser scanning of moving objects
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.
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....
Infant search and object permanence: a meta-analysis of the A-not-B error.
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
Error analysis of numerical gravitational waveforms from coalescing binary black holes
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.
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
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.
Earth orientation from lunar laser ranging and an error analysis of polar motion services
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.
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.
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.
Secondary data analysis of large data sets in urology: successes and errors to avoid.
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
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
Teamwork and error in the operating room: analysis of skills and roles.
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.
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
A Simple Exact Error Rate Analysis for DS-CDMA with Arbitrary Pulse Shape in Flat Nakagami Fading
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).
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.
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.
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...
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.
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
Mobility and Position Error Analysis of a Complex Planar Mechanism with Redundant Constraints
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.
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
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....
Error performance analysis in K-tier uplink cellular networks using a stochastic geometric approach
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.
Analysis of family-wise error rates in statistical parametric mapping using random field theory.
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.
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
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.
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
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.
Bayesian analysis of data and model error in rainfall-runoff hydrological models
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
Errors Analysis of Students in Mathematics Department to Learn Plane Geometry
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.
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...
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)
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.
Analysis and compensation of synchronous measurement error for multi-channel laser interferometer
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.
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.
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
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
Review of U.S. Army Unmanned Aerial Systems Accident Reports: Analysis of Human Error Contributions
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
Height-Error Analysis for the FAA-Air Force Replacement Radar Program (FARR)
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
Analysis of the “naming game” with learning errors in communications
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 ...
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
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
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
An Analysis of Lexical Errors of Korean Language Learners: Some American College Learners' Case
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…
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.
Sources of Error and the Statistical Formulation of M S: m b Seismic Event Screening Analysis
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.
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
Ergodic Capacity Analysis of Free-Space Optical Links with Nonzero Boresight Pointing Errors
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.
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.
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.,
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.,.
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.
Prepopulated radiology report templates: a prospective analysis of error rate and turnaround time.
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.
Phase correction and error estimation in InSAR time series analysis
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
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)
Output Error Analysis of Planar 2-DOF Five-bar Mechanism
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.
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.
LENUS (Irish Health Repository)
2011-01-01
If VR-based medical training and assessment is to improve patient care and safety (i.e. a genuine health gain), it has to be based on clinically relevant measurement of performance. Metrics on errors are particularly useful for capturing and correcting undesired behaviors before they occur in the operating room. However, translating clinically relevant metrics and errors into meaningful system design is a challenging process. This paper discusses how an existing task and error analysis was translated into the system design of a VR-based training and assessment environment for Ultrasound Guided Regional Anesthesia (UGRA).
Directory of Open Access Journals (Sweden)
Cai Ligang
2017-01-01
Full Text Available Instead improving the accuracy of machine tool by increasing the precision of key components level blindly in the production process, the method of combination of SNR quality loss function and machine tool geometric error correlation analysis to optimize five-axis machine tool geometric errors will be adopted. Firstly, the homogeneous transformation matrix method will be used to build five-axis machine tool geometric error modeling. Secondly, the SNR quality loss function will be used for cost modeling. And then, machine tool accuracy optimal objective function will be established based on the correlation analysis. Finally, ISIGHT combined with MATLAB will be applied to optimize each error. The results show that this method is reasonable and appropriate to relax the range of tolerance values, so as to reduce the manufacturing cost of machine tools.
Fluid dynamic analysis and experimental study of a low radiation error temperature sensor
Energy Technology Data Exchange (ETDEWEB)
Yang, Jie, E-mail: yangjie396768@163.com [Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing 210044 (China); School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Liu, Qingquan, E-mail: andyucd@163.com [Jiangsu Key Laboratory of Meteorological Observation and Information Processing, Nanjing 210044 (China); Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology, Nanjing 210044 (China); Dai, Wei, E-mail: daiweiilove@163.com [Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing 210044 (China); School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Ding, Renhui, E-mail: drhabcd@sina.com [Jiangsu Meteorological Observation Center, Nanjing 210008 (China)
2017-01-30
To improve the air temperature observation accuracy, a low radiation error temperature sensor is proposed. A Computational Fluid Dynamics (CFD) method is implemented to obtain radiation errors under various environmental conditions. The low radiation error temperature sensor, a naturally ventilated radiation shield, a thermometer screen and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean radiation errors of the naturally ventilated radiation shield and the thermometer screen are 0.57 °C and 0.32 °C, respectively. In contrast, the mean radiation error of the low radiation error temperature sensor is 0.05 °C. The low radiation error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature measurement result. - Highlights: • A CFD method is applied to obtain a quantitative solution of radiation error. • A temperature sensor is proposed to minimize radiation error. • The radiation error of the temperature sensor is on the order of 0.05 °C.
Oh, Eric J; Shepherd, Bryan E; Lumley, Thomas; Shaw, Pamela A
2018-04-15
For time-to-event outcomes, a rich literature exists on the bias introduced by covariate measurement error in regression models, such as the Cox model, and methods of analysis to address this bias. By comparison, less attention has been given to understanding the impact or addressing errors in the failure time outcome. For many diseases, the timing of an event of interest (such as progression-free survival or time to AIDS progression) can be difficult to assess or reliant on self-report and therefore prone to measurement error. For linear models, it is well known that random errors in the outcome variable do not bias regression estimates. With nonlinear models, however, even random error or misclassification can introduce bias into estimated parameters. We compare the performance of 2 common regression models, the Cox and Weibull models, in the setting of measurement error in the failure time outcome. We introduce an extension of the SIMEX method to correct for bias in hazard ratio estimates from the Cox model and discuss other analysis options to address measurement error in the response. A formula to estimate the bias induced into the hazard ratio by classical measurement error in the event time for a log-linear survival model is presented. Detailed numerical studies are presented to examine the performance of the proposed SIMEX method under varying levels and parametric forms of the error in the outcome. We further illustrate the method with observational data on HIV outcomes from the Vanderbilt Comprehensive Care Clinic. Copyright © 2017 John Wiley & Sons, Ltd.
Li, S; Lu, M; Kim, J; Glide-Hurst, C; Chetty, I; Zhong, H
2012-06-01
Purpose Clinical implementation of adaptive treatment planning is limited by the lack of quantitative tools to assess deformable image registration errors (R-ERR). The purpose of this study was to develop a method, using finite element modeling (FEM), to estimate registration errors based on mechanical changes resulting from them. Methods An experimental platform to quantify the correlation between registration errors and their mechanical consequences was developed as follows: diaphragm deformation was simulated on the CT images in patients with lung cancer using a finite element method (FEM). The simulated displacement vector fields (F-DVF) were used to warp each CT image to generate a FEM image. B-Spline based (Elastix) registrations were performed from reference to FEM images to generate a registration DVF (R-DVF). The F- DVF was subtracted from R-DVF. The magnitude of the difference vector was defined as the registration error, which is a consequence of mechanically unbalanced energy (UE), computed using 'in-house-developed' FEM software. A nonlinear regression model was used based on imaging voxel data and the analysis considered clustered voxel data within images. Results A regression model analysis showed that UE was significantly correlated with registration error, DVF and the product of registration error and DVF respectively with R̂2=0.73 (R=0.854). The association was verified independently using 40 tracked landmarks. A linear function between the means of UE values and R- DVF*R-ERR has been established. The mean registration error (N=8) was 0.9 mm. 85.4% of voxels fit this model within one standard deviation. Conclusions An encouraging relationship between UE and registration error has been found. These experimental results suggest the feasibility of UE as a valuable tool for evaluating registration errors, thus supporting 4D and adaptive radiotherapy. The research was supported by NIH/NCI R01CA140341. © 2012 American Association of Physicists in
International Nuclear Information System (INIS)
Takagawa, Kenichi; Miyazaki, Takamasa; Gofuku, Akio; Iida, Hiroyasu
2007-01-01
Since many of the adverse events that have occurred in nuclear power plants in Japan and abroad have been related to maintenance or operation, it is necessary to plan preventive measures based on detailed analyses of human errors made by maintenance workers or operators. Therefore, before planning preventive measures, we developed a new method of analyzing human errors. Since each human error is an unsafe action caused by some misjudgement made by a person, we decided to classify them into six categories according to the stage in the judgment process in which the error was made. By further classifying each error into either an omission-type or commission-type, we produced 12 categories of errors. Then, we divided them into the two categories of basic error tendencies and individual error tendencies, and categorized background factors into four categories: imperfect planning; imperfect facilities or tools; imperfect environment; and imperfect instructions or communication. We thus defined the factors in each category to make it easy to identify factors that caused the error. Then using this method, we studied the characteristics of human errors that involved maintenance workers and planners since many maintenance errors have occurred. Among the human errors made by workers (worker errors) during the implementation stage, the following three types were prevalent with approximately 80%: commission-type 'projection errors', omission-type comprehension errors' and commission type 'action errors'. The most common among the individual factors of worker errors was 'repetition or habit' (schema), based on the assumption of a typical situation, and the half number of the 'repetition or habit' cases (schema) were not influenced by any background factors. The most common background factor that contributed to the individual factor was 'imperfect work environment', followed by 'insufficient knowledge'. Approximately 80% of the individual factors were 'repetition or habit' or
Analyse des erreurs dans les calculs sur ordinateurs Error Analysis in Computing
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Vignes J.
2006-11-01
Full Text Available La méthode présentée ici permet d'évaluer l'erreur sur les résultats d'algorithmes, erreurs dues à l'arithmétique à précision limitée de la machines L'idée de base de cette méthode est qu'à un algorithme donné fournissant un résultat algébrique unique r, correspond en informatique un ensemble R de résultats numériques qui sont tous représentatifs de résultat exact r. La méthode de permutation-perturbation que nous présentons ici permet d'obtenir les éléments de R. La perturbation agit sur les données et résultats de chaque opération élémentaire. La permutation agit sur l'ordre d'exécution des opérations. Une étude statistique des éléments de R permet d'estimer l'erreur commise. Dans la pratique, il suffit de 2 ou 3 éléments de R pour connaître cette erreur. This paper describes a new method for evaluating the error in the results of computation of an algorithm. The basic idea underlying the method is that while in algebra a given algorithm provides a single result r, this same algorithm carried out on a computer provides a set R of numerical results that are ail representative of the exact algebraic result r. The permutation-perturbation method described here can be used to obtain the elements of R. The perturbation acts on the data and results of each elementary operation, and the permutation acts on the order in which operations are carried out. A statistical analysis of the elements of R is performed to determine the error committed. In practice, 2 to 4 R elements are sufficient for determining the error.
Modeling coherent errors in quantum error correction
Greenbaum, Daniel; Dutton, Zachary
2018-01-01
Analysis of quantum error correcting codes is typically done using a stochastic, Pauli channel error model for describing the noise on physical qubits. However, it was recently found that coherent errors (systematic rotations) on physical data qubits result in both physical and logical error rates that differ significantly from those predicted by a Pauli model. Here we examine the accuracy of the Pauli approximation for noise containing coherent errors (characterized by a rotation angle ɛ) under the repetition code. We derive an analytic expression for the logical error channel as a function of arbitrary code distance d and concatenation level n, in the small error limit. We find that coherent physical errors result in logical errors that are partially coherent and therefore non-Pauli. However, the coherent part of the logical error is negligible at fewer than {ε }-({dn-1)} error correction cycles when the decoder is optimized for independent Pauli errors, thus providing a regime of validity for the Pauli approximation. Above this number of correction cycles, the persistent coherent logical error will cause logical failure more quickly than the Pauli model would predict, and this may need to be combated with coherent suppression methods at the physical level or larger codes.
Ansari, Imran Shafique; Yilmaz, Ferkan; Alouini, Mohamed-Slim
2015-01-01
In this work, we present a unified performance analysis of a free-space optical (FSO) link that accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection (IM/DD) as well as heterodyne detection). More specifically, we present unified exact closedform expressions for the cumulative distribution function, the probability density function, the moment generating function, and the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system, all in terms of the Meijer’s G function except for the moments that is in terms of simple elementary functions. We then capitalize on these unified results to offer unified exact closed-form expressions for various performance metrics of FSO link transmission systems, such as, the outage probability, the scintillation index (SI), the average error rate for binary and M-ary modulation schemes, and the ergodic capacity (except for IM/DD technique, where we present closed-form lower bound results), all in terms of Meijer’s G functions except for the SI that is in terms of simple elementary functions. Additionally, we derive the asymptotic results for all the expressions derived earlier in terms of Meijer’s G function in the high SNR regime in terms of simple elementary functions via an asymptotic expansion of the Meijer’s G function. We also derive new asymptotic expressions for the ergodic capacity in the low as well as high SNR regimes in terms of simple elementary functions via utilizing moments. All the presented results are verified via computer-based Monte-Carlo simulations.
Pertinence analysis of intensity-modulated radiation therapy dosimetry error and parameters of beams
International Nuclear Information System (INIS)
Chi Zifeng; Liu Dan; Cao Yankun; Li Runxiao; Han Chun
2012-01-01
Objective: To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification. Methods: Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria. The plans were copied to water-phantom, 0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose. The statistical data of the parameters of beams for the 43 cases were collected, and the relationships among them were analyzed. The statistical data of the dosimetry error were collected, and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results. Results: The parameters of beams were correlated among each other. Obvious affiliation existed between the dose accuracy and parameter settings. When the beam segment number of IMRT plan was more than 80, the dose deviation would be greater than 3%; however, if the beam segment number was less than 80, the dose deviation was smaller than 3%. When the beam segment number was more than 100, part of the dose deviation of this plan was greater than 4%. On the contrary, if the beam segment number was less than 100, the dose deviation was smaller than 4% definitely. Conclusions: In order to decrease the absolute dose verification error, less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80. (authors)
Ansari, Imran Shafique
2015-08-12
In this work, we present a unified performance analysis of a free-space optical (FSO) link that accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection (IM/DD) as well as heterodyne detection). More specifically, we present unified exact closedform expressions for the cumulative distribution function, the probability density function, the moment generating function, and the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system, all in terms of the Meijer’s G function except for the moments that is in terms of simple elementary functions. We then capitalize on these unified results to offer unified exact closed-form expressions for various performance metrics of FSO link transmission systems, such as, the outage probability, the scintillation index (SI), the average error rate for binary and M-ary modulation schemes, and the ergodic capacity (except for IM/DD technique, where we present closed-form lower bound results), all in terms of Meijer’s G functions except for the SI that is in terms of simple elementary functions. Additionally, we derive the asymptotic results for all the expressions derived earlier in terms of Meijer’s G function in the high SNR regime in terms of simple elementary functions via an asymptotic expansion of the Meijer’s G function. We also derive new asymptotic expressions for the ergodic capacity in the low as well as high SNR regimes in terms of simple elementary functions via utilizing moments. All the presented results are verified via computer-based Monte-Carlo simulations.
Phakic intraocular lenses for the treatment of refractive errors: an evidence-based analysis.
2009-01-01
The objective of this analysis is to review the effectiveness, safety, and cost-effectiveness of phakic intraocular lenses (pIOLs) for the treatment of myopia, hyperopia, and astigmatism. CONDITION AND TARGET POPULATION REFRACTIVE ERRORS: Refractive errors occur when the eye cannot focus light properly. In myopia (near- or short-sightedness), distant objects appear blurry because the axis of the eye is too long or the cornea is too steep, so light becomes focused in front of the retina. Hyperopia (far sightedness) occurs when light is focused behind the retina causing nearby objects to appear blurry. In astigmatism, blurred or distorted vision occurs when light is focused at two points rather than one due to an irregularly shaped cornea or lens. Refractive errors are common worldwide, but high refractive errors are less common. In the United States, the prevalence of high myopia (≤ -5 D) in people aged 20 to 39, 40 to 59, and 60 years and older is 7.4% (95% confidence interval [CI], 6.5% - 8.3%), 7.8% (95% CI, 6.4% - 8.6%), and 3.1% (95% CI, 2.2% - 3.9%), respectively. The prevalence of high hyperopia (≥ 3 D) is 1.0% (95% CI, .6% - 1.4%), 2.4% (95% CI, 1.7% - 3.0%), and 10.0% (95% CI, 9.1% - 10.9%) for the same age groupings. Finally, the prevalence of astigmatism (≥ 1 D cylinder) is 23.1% (95% CI, 21.6% - 24.5%), 27.6% (95% CI, 25.8% - 29.3%) and 50.1% (48.2% - 52.0%). LOW VISION: According to the Ontario Schedule of Benefits, low visual acuity is defined by a best spectacle corrected visual acuity (BSCVA) of 20/50 (6/15) or less in the better eye and not amenable to further medical and/or surgical treatment. Similarly, the Ontario Assistive Devices Program defines low vision as BSCVA in the better eye in the range of 20/70 or less that cannot be corrected medically, surgically, or with ordinary eyeglasses or contact lenses. Estimates of the prevalence of low vision vary. Using the criteria of BSCVA ranging from 20/70 to 20/160, one study estimated that 35
International Nuclear Information System (INIS)
Jong, E. de J. de; Bosch, J.J. ten
1985-01-01
The microradiographic method, used to measure the mineral content in slices of mineralised tissues as a function of position, is analysed. The total error in the measured mineral content is split into systematic errors per microradiogram and random noise errors. These errors are measured quantitatively. Predominant contributions to systematic errors appear to be x-ray beam inhomogeneity, the determination of the step wedge thickness and stray light in the densitometer microscope, while noise errors are under the influence of the choice of film, the value of the optical film transmission of the microradiographic image and the area of the densitometer window. Optimisation criteria are given. The authors used these criteria, together with the requirement that the method be fast and easy to build an optimised microradiographic system. (author)
International Nuclear Information System (INIS)
Varde, P. V.; Lee, D. Y.; Han, J. B.
2003-03-01
A case of study on human reliability analysis has been performed as part of reliability analysis of digital protection system of the reactor automatically actuates the shutdown system of the reactor when demanded. However, the safety analysis takes credit for operator action as a diverse mean for tripping the reactor for, though a low probability, ATWS scenario. Based on the available information two cases, viz., human error in tripping the reactor and calibration error for instrumentations in protection system, have been analyzed. Wherever applicable a parametric study has also been performed
Error Analysis of Ia Supernova and Query on Cosmic Dark Energy ...
Indian Academy of Sciences (India)
2007), we find that. 3.796% of the data is an outline of 2.6σ based on the average total observational error of the distance modulus of SNIa, 0.31 m . Obviously, the distance modulus error deviates Gaussian distribution seriously, and it is not suitable to calculate the system- atic error σsys of SNIa by the χ2 check test method.
Error analysis of the phase-shifting technique when applied to shadow moire
International Nuclear Information System (INIS)
Han, Changwoon; Han Bongtae
2006-01-01
An exact solution for the intensity distribution of shadow moire fringes produced by a broad spectrum light is presented. A mathematical study quantifies errors in fractional fringe orders determined by the phase-shifting technique, and its validity is corroborated experimentally. The errors vary cyclically as the distance between the reference grating and the specimen increases. The amplitude of the maximum error is approximately 0.017 fringe, which defines the theoretical limit of resolution enhancement offered by the phase-shifting technique
Water flux in animals: analysis of potential errors in the tritiated water method
Energy Technology Data Exchange (ETDEWEB)
Nagy, K.A.; Costa, D.
1979-03-01
Laboratory studies indicate that tritiated water measurements of water flux are accurate to within -7 to +4% in mammals, but errors are larger in some reptiles. However, under conditions that can occur in field studies, errors may be much greater. Influx of environmental water vapor via lungs and skin can cause errors exceeding +-50% in some circumstances. If water flux rates in an animal vary through time, errors approach +-15% in extreme situations, but are near +-3% in more typical circumstances. Errors due to fractional evaporation of tritiated water may approach -9%. This error probably varies between species. Use of an inappropriate equation for calculating water flux from isotope data can cause errors exceeding +-100%. The following sources of error are either negligible or avoidable: use of isotope dilution space as a measure of body water volume, loss of nonaqueous tritium bound to excreta, binding of tritium with nonaqueous substances in the body, radiation toxicity effects, and small analytical errors in isotope measurements. Water flux rates measured with tritiated water should be within +-10% of actual flux rates in most situations.
International Nuclear Information System (INIS)
Liu Xiaoxue; Li Ziqiang; Zhao Hongsheng; Zhang Kaihong; Tang Chunhe
2014-01-01
The thicknesses of four coatings of HTR coated fuel particle are very important parameters. It is indispensable to control the thickness of four coatings of coated fuel particles for the safety of HTR. A measurement method, ceramographic sample-microanalysis method, to analyze the thickness of coatings was developed. During the process of ceramographic sample-microanalysis, there are two main errors, including ceramographic sample preparation error and thickness measurement error. With the development of microscopic techniques, thickness measurement error can be easily controlled to meet the design requirements. While, due to the coated particles are spherical particles of different diameters ranged from 850 to 1000μm, the sample preparation process will introduce an error. And this error is different from one sample to another. It’s also different from one particle to another in the same sample. In this article, the error of the ceramographic sample preparation was calculated and analyzed. Results show that the error introduced by sample preparation is minor. The minor error of sample preparation guarantees the high accuracy of the mentioned method, which indicates this method is a proper method to measure the thickness of four coatings of coated particles. (author)
Directory of Open Access Journals (Sweden)
Yanrui Su
2015-01-01
Full Text Available As the position sensor, photoelectric angle encoder affects the accuracy and stability of telescope control system (TCS. A TCS-based subdivision error compensation method for encoder is proposed. Six types of subdivision error sources are extracted through mathematical expressions of subdivision signals first. Then the period length relationships between subdivision signals and subdivision errors are deduced. And the error compensation algorithm only utilizing the shaft position of TCS is put forward, along with two control models; Model I is that the algorithm applies only to the speed loop of TCS and Model II is applied to both speed loop and position loop. Combined with actual project, elevation jittering phenomenon of the telescope is discussed to decide the necessity of DC-type subdivision error compensation. Low-speed elevation performance before and after error compensation is compared to help decide that Model II is preferred. In contrast to original performance, the maximum position error of the elevation with DC subdivision error compensation is reduced by approximately 47.9% from 1.42″ to 0.74″. The elevation gets a huge decrease in jitters. This method can compensate the encoder subdivision errors effectively and improve the stability of TCS.
Water flux in animals: analysis of potential errors in the tritiated water method
International Nuclear Information System (INIS)
Nagy, K.A.; Costa, D.
1979-03-01
Laboratory studies indicate that tritiated water measurements of water flux are accurate to within -7 to +4% in mammals, but errors are larger in some reptiles. However, under conditions that can occur in field studies, errors may be much greater. Influx of environmental water vapor via lungs and skin can cause errors exceeding +-50% in some circumstances. If water flux rates in an animal vary through time, errors approach +-15% in extreme situations, but are near +-3% in more typical circumstances. Errors due to fractional evaporation of tritiated water may approach -9%. This error probably varies between species. Use of an inappropriate equation for calculating water flux from isotope data can cause errors exceeding +-100%. The following sources of error are either negligible or avoidable: use of isotope dilution space as a measure of body water volume, loss of nonaqueous tritium bound to excreta, binding of tritium with nonaqueous substances in the body, radiation toxicity effects, and small analytical errors in isotope measurements. Water flux rates measured with tritiated water should be within +-10% of actual flux rates in most situations
Error analysis of dimensionless scaling experiments with multiple points using linear regression
International Nuclear Information System (INIS)
Guercan, Oe.D.; Vermare, L.; Hennequin, P.; Bourdelle, C.
2010-01-01
A general method of error estimation in the case of multiple point dimensionless scaling experiments, using linear regression and standard error propagation, is proposed. The method reduces to the previous result of Cordey (2009 Nucl. Fusion 49 052001) in the case of a two-point scan. On the other hand, if the points follow a linear trend, it explains how the estimated error decreases as more points are added to the scan. Based on the analytical expression that is derived, it is argued that for a low number of points, adding points to the ends of the scanned range, rather than the middle, results in a smaller error estimate. (letter)
Directory of Open Access Journals (Sweden)
Pang Fubin
2015-09-01
Full Text Available In this paper the origin problem of data synchronization is analyzed first, and then three common interpolation methods are introduced to solve the problem. Allowing for the most general situation, the paper divides the interpolation error into harmonic and transient interpolation error components, and the error expression of each method is derived and analyzed. Besides, the interpolation errors of linear, quadratic and cubic methods are computed at different sampling rates, harmonic orders and transient components. Further, the interpolation accuracy and calculation amount of each method are compared. The research results provide theoretical guidance for selecting the interpolation method in the data synchronization application of electronic transformer.
International Nuclear Information System (INIS)
Vignes, J.
1986-01-01
Any result of algorithms provided by a computer always contains an error resulting from floating-point arithmetic round-off error propagation. Furthermore signal processing algorithms are also generally performed with data containing errors. The permutation-perturbation method, also known under the name CESTAC (controle et estimation stochastique d'arrondi de calcul) is a very efficient practical method for evaluating these errors and consequently for estimating the exact significant decimal figures of any result of algorithms performed on a computer. The stochastic approach of this method, its probabilistic proof, and the perfect agreement between the theoretical and practical aspects are described in this paper [fr
A method for local transport analysis in tokamaks with error calculation
International Nuclear Information System (INIS)
Hogeweij, G.M.D.; Hordosy, G.; Lopes Cardozo, N.J.
1989-01-01
Global transport studies have revealed that heat transport in a tokamak is anomalous, but cannot provide information about the nature of the anomaly. Therefore, local transport analysis is essential for the study of anomalous transport. However, the determination of local transport coefficients is not a trivial affair. Generally speaking one can either directly measure the heat diffusivity, χ, by means of heat pulse propagation analysis, or deduce the profile of χ from measurements of the profiles of the temperature, T, and the power deposition. Here we are concerned only with the latter method, the local power balance analysis. For the sake of clarity heat diffusion only is considered: ρ=-gradT/q (1) where ρ=κ -1 =(nχ) -1 is the heat resistivity and q is the heat flux per unit area. It is assumed that the profiles T(r) and q(r) are given with some experimental error. In practice T(r) is measured directly, e.g. from ECE spectroscopy, while q(r) is deduced from the power deposition and loss profiles. The latter cannot be measured directly and is partly determined on the basis of models. This complication will not be considered here. Since in eq. (1) the gradient of T appears, noise on T can severely affect the solution ρ. This means that in general some form of smoothing must be applied. A criterion is needed to select the optimal smoothing. Too much smoothing will wipe out the details, whereas with too little smoothing the noise will distort the reconstructed profile of ρ. Here a new method to solve eq. (1) is presented which expresses ρ(r) as a cosine-series. The coefficients of this series are given as linear combinations of the Fourier coefficients of the measured T- and q-profiles. This formulation allows 1) the stable and accurate calculation of the ρ-profile, and 2) the analytical calculation of the error in this profile. (author) 5 refs., 3 figs
Melnychuk, O; Grassellino, A; Romanenko, A
2014-12-01
In this paper, we discuss error analysis for intrinsic quality factor (Q0) and accelerating gradient (Eacc) measurements in superconducting radio frequency (SRF) resonators. The analysis is applicable for cavity performance tests that are routinely performed at SRF facilities worldwide. We review the sources of uncertainties along with the assumptions on their correlations and present uncertainty calculations with a more complete procedure for treatment of correlations than in previous publications [T. Powers, in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27]. Applying this approach to cavity data collected at Vertical Test Stand facility at Fermilab, we estimated total uncertainty for both Q0 and Eacc to be at the level of approximately 4% for input coupler coupling parameter β1 in the [0.5, 2.5] range. Above 2.5 (below 0.5) Q0 uncertainty increases (decreases) with β1 whereas Eacc uncertainty, in contrast with results in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27], is independent of β1. Overall, our estimated Q0 uncertainty is approximately half as large as that in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24-27].
International Nuclear Information System (INIS)
Erdtmann, G.
1993-08-01
A sufficiently accurate characterization of the neutron flux and spectrum, i.e. the determination of the thermal flux, the flux ratio and the epithermal flux spectrum shape factor, α, is a prerequisite for all types of absolute and monostandard methods of reactor neutron activation analysis. A convenient method for these measurements is the bare triple monitor method. However, the results of this method, are very imprecise, because there are high error propagation factors form the counting errors of the monitor activities. Procedures are described to calculate the errors of the flux parameters, the α-dependent cross-section ratios, and of the analytical results from the errors of the activities of the monitor isotopes. They are included in FORTRAN programs which also allow a graphical representation of the results. A great number of examples were calculated for ten different irradiation facilities in four reactors and for 28 elements. Plots of the results are presented and discussed. (orig./HP) [de
Hincapie, Ana L; Slack, Marion; Malone, Daniel C; MacKinnon, Neil J; Warholak, Terri L
2016-01-01
Patients may be the most reliable reporters of some aspects of the health care process; their perspectives should be considered when pursuing changes to improve patient safety. The authors evaluated the association between patients' perceived health care quality and self-reported medical, medication, and laboratory errors in a multinational sample. The analysis was conducted using the 2010 Commonwealth Fund International Health Policy Survey, a multinational consumer survey conducted in 11 countries. Quality of care was measured by a multifaceted construct developed using Rasch techniques. After adjusting for potentially important confounding variables, an increase in respondents' perceptions of care coordination decreased the odds of self-reporting medical errors, medication errors, and laboratory errors (P < .001). As health care stakeholders continue to search for initiatives that improve care experiences and outcomes, this study's results emphasize the importance of guaranteeing integrated care.
Li, Xingxing
2014-05-01
displacements is accompanied by a drift due to the potential uncompensated errors. Li et al. (2013) presented a temporal point positioning (TPP) method to quickly capture coseismic displacements with a single GPS receiver in real-time. The TPP approach can overcome the convergence problem of precise point positioning (PPP), and also avoids the integration and de-trending process of the variometric approach. The performance of TPP is demonstrated to be at few centimeters level of displacement accuracy for even twenty minutes interval with real-time precise orbit and clock products. In this study, we firstly present and compare the observation models and processing strategies of the current existing single-receiver methods for real-time GPS seismology. Furthermore, we propose several refinements to the variometric approach in order to eliminate the drift trend in the integrated coseismic displacements. The mathematical relationship between these methods is discussed in detail and their equivalence is also proved. The impact of error components such as satellite ephemeris, ionospheric delay, tropospheric delay, and geometry change on the retrieved displacements are carefully analyzed and investigated. Finally, the performance of these single-receiver approaches for real-time GPS seismology is validated using 1 Hz GPS data collected during the Tohoku-Oki earthquake (Mw 9.0, March 11, 2011) in Japan. It is shown that few centimeters accuracy of coseismic displacements is achievable. Keywords: High-rate GPS; real-time GPS seismology; a single receiver; PPP; variometric approach; temporal point positioning; error analysis; coseismic displacement; fault slip inversion;
An analysis of anatomic landmark mobility and setup errors in radiotherapy for lung cancer
International Nuclear Information System (INIS)
Samson, M.J.; Soernsen de Koste, J.R. van; Boer, J.C.J. de; Tankink, J.J.; Verstraate, M.B.J.; Essers, M.; Visser, A.G.; Senan, S.
1997-01-01
case for the SD of the translations in the cranial direction of the clavicle, aortic arch and upper thoracic wall. The carina was found to be relatively mobile (up to 6 mm) in both directions. The SD for in-plane rotations was negligible (<0.5 deg.) for all structures. The interpatient variation was very small (SD < 0.5 mm). In a preliminary analysis of patient setup, the random errors for translations are 2.0 mm in the lateral direction and 2.4 mm in the cranial direction (1 SD). The standard deviations of systematic errors are about 3 mm in both directions. In plane rotations were found to be negligible. Conclusions: We have identified a number of structures which exhibit little internal motion in the frontal plane, and recommend that a combination of these structures be used as anatomic landmarks for setup verification during radiotherapy of thoracic tumors. Preliminary results indicate that setup errors of patients with lung cancer in our center appear to be acceptable, even though no specific immobilization devices were used
Liu, Yan; Salvendy, Gavriel
2009-05-01
This paper aims to demonstrate the effects of measurement errors on psychometric measurements in ergonomics studies. A variety of sources can cause random measurement errors in ergonomics studies and these errors can distort virtually every statistic computed and lead investigators to erroneous conclusions. The effects of measurement errors on five most widely used statistical analysis tools have been discussed and illustrated: correlation; ANOVA; linear regression; factor analysis; linear discriminant analysis. It has been shown that measurement errors can greatly attenuate correlations between variables, reduce statistical power of ANOVA, distort (overestimate, underestimate or even change the sign of) regression coefficients, underrate the explanation contributions of the most important factors in factor analysis and depreciate the significance of discriminant function and discrimination abilities of individual variables in discrimination analysis. The discussions will be restricted to subjective scales and survey methods and their reliability estimates. Other methods applied in ergonomics research, such as physical and electrophysiological measurements and chemical and biomedical analysis methods, also have issues of measurement errors, but they are beyond the scope of this paper. As there has been increasing interest in the development and testing of theories in ergonomics research, it has become very important for ergonomics researchers to understand the effects of measurement errors on their experiment results, which the authors believe is very critical to research progress in theory development and cumulative knowledge in the ergonomics field.
Human Error Analysis Project (HEAP) - The Fourth Pilot Study: Scoring and Analysis of Raw Data Types
International Nuclear Information System (INIS)
Hollnagel, Erik; Braarud; Per Oeyvind; Droeivoldsmo, Asgeir; Follesoe; Knut; Helgar, Stein; Kaarstad, Magnhild
1996-01-01
Pilot study No. 4 rounded off the series of pilot studies by looking at the important issue of the quality of the various data sources. The preceding experiments had clearly shown that that it was necessary to use both concurrent and interrupted verbal protocols, and also that information about eye movements was very valuable. The effort and resources needed to analyse a combination of the different data sources is, however, significant, and it was therefore important to find out whether one or more of the data sources could replace another. In order to determine this issue, pilot study No. 4 looked specifically at the quality of information provided by different data sources. The main hypotheses were that information about operators' diagnosis and decision making would be provided by verbal protocols, expert commentators, and auto-confrontation protocols, that the data sources would be valid, and that they would complement each other. The study used three main data sources: (1) concurrent verbal protocols, which were the operators' verbalisations during the experiment; (2) expert commentator reports, which were descriptions by process experts of the operators' performance; and (3) auto-confrontation, which were the operators' comments on their performance based on a replay of the performance recording minus the concurrent verbal protocol. Additional data sources were eye movement recordings, process data, alarms, etc. The three main data sources were treated as independent variables and applied according to an experimental design that facilitated the test of the main hypotheses. The pilot study produced altogether 59 verbal protocols, some of which were in Finnish. After a translation into English, each protocol was analysed and scored according to a specific scheme. The scoring was designed to facilitate the evaluation of the experimental hypotheses. Due to the considerable work involved, the analysis process has only been partly completed, and no firm results
SBUV version 8.6 Retrieval Algorithm: Error Analysis and Validation Technique
Kramarova, N. A.; Bhartia, P. K.; Frith, P. K.; McPeters, S. M.; Labow, R. D.; Taylor, G.; Fisher, S.; DeLand, M.
2012-01-01
SBUV version 8.6 algorithm was used to reprocess data from the Back Scattered Ultra Violet (BUV), the Solar Back Scattered Ultra Violet (SBUV) and a number of SBUV/2 instruments, which 'span a 41-year period from 1970 to 2011 (except a 5-year gap in the 1970s)[see Bhartia et al, 2012]. In the new version Daumont et al. [1992] ozone cross section were used, and new ozone [McPeters et ai, 2007] and cloud climatologies Doiner and Bhartia, 1995] were implemented. The algorithm uses the Optimum Estimation technique [Rodgers, 2000] to retrieve ozone profiles as ozone layer (partial column, DU) on 21 pressure layers. The corresponding total ozone values are calculated by summing ozone columns at individual layers. The algorithm is optimized to accurately retrieve monthly zonal mean (mzm) profiles rather than an individual profile, since it uses monthly zonal mean ozone climatology as the A Priori. Thus, the SBUV version 8.6 ozone dataset is better suited for long-term trend analysis and monitoring ozone changes rather than for studying short-term ozone variability. Here we discuss some characteristics of the SBUV algorithm and sources of error in the SBUV profile and total ozone retrievals. For the first time the Averaging Kernels, smoothing errors and weighting functions (or Jacobians) are included in the SBUV metadata. The Averaging Kernels (AK) represent the sensitivity of the retrieved profile to the true state and contain valuable information about the retrieval algorithm, such as Vertical Resolution, Degrees of Freedom for Signals (DFS) and Retrieval Efficiency [Rodgers, 2000]. Analysis of AK for mzm ozone profiles shows that the total number of DFS for ozone profiles varies from 4.4 to 5.5 out of 6-9 wavelengths used for retrieval. The number of wavelengths in turn depends on solar zenith angles. Between 25 and 0.5 hPa, where SBUV vertical resolution is the highest, DFS for individual layers are about 0.5.
Analysis of error type and frequency in apraxia of speech among Portuguese speakers
Directory of Open Access Journals (Sweden)
Maysa Luchesi Cera
Full Text Available Abstract Most studies characterizing errors in the speech of patients with apraxia involve English language. Objectives: To analyze the types and frequency of errors produced by patients with apraxia of speech whose mother tongue was Brazilian Portuguese. Methods: 20 adults with apraxia of speech caused by stroke were assessed. The types of error committed by patients were analyzed both quantitatively and qualitatively, and frequencies compared. Results: We observed the presence of substitution, omission, trial-and-error, repetition, self-correction, anticipation, addition, reiteration and metathesis, in descending order of frequency, respectively. Omission type errors were one of the most commonly occurring whereas addition errors were infrequent. These findings differed to those reported in English speaking patients, probably owing to differences in the methodologies used for classifying error types; the inclusion of speakers with apraxia secondary to aphasia; and the difference in the structure of Portuguese language to English in terms of syllable onset complexity and effect on motor control. Conclusions: The frequency of omission and addition errors observed differed to the frequency reported for speakers of English.
Running Records and First Grade English Learners: An Analysis of Language Related Errors
Briceño, Allison; Klein, Adria F.
2018-01-01
The purpose of this study was to determine if first-grade English Learners made patterns of language related errors when reading, and if so, to identify those patterns and how teachers coded language related errors when analyzing English Learners' running records. Using research from the fields of both literacy and Second Language Acquisition, we…
Analysis of errors in spectral reconstruction with a Laplace transform pair model
International Nuclear Information System (INIS)
Archer, B.R.; Bushong, S.C.
1985-01-01
The sensitivity of a Laplace transform pair model for spectral reconstruction to random errors in attenuation measurements of diagnostic x-ray units has been investigated. No spectral deformation or significant alteration resulted from the simulated attenuation errors. It is concluded that the range of spectral uncertainties to be expected from the application of this model is acceptable for most scientific applications. (author)
Analysis on the dynamic error for optoelectronic scanning coordinate measurement network
Shi, Shendong; Yang, Linghui; Lin, Jiarui; Guo, Siyang; Ren, Yongjie
2018-01-01
Large-scale dynamic three-dimension coordinate measurement technique is eagerly demanded in equipment manufacturing. Noted for advantages of high accuracy, scale expandability and multitask parallel measurement, optoelectronic scanning measurement network has got close attention. It is widely used in large components jointing, spacecraft rendezvous and docking simulation, digital shipbuilding and automated guided vehicle navigation. At present, most research about optoelectronic scanning measurement network is focused on static measurement capacity and research about dynamic accuracy is insufficient. Limited by the measurement principle, the dynamic error is non-negligible and restricts the application. The workshop measurement and positioning system is a representative which can realize dynamic measurement function in theory. In this paper we conduct deep research on dynamic error resources and divide them two parts: phase error and synchronization error. Dynamic error model is constructed. Based on the theory above, simulation about dynamic error is carried out. Dynamic error is quantized and the rule of volatility and periodicity has been found. Dynamic error characteristics are shown in detail. The research result lays foundation for further accuracy improvement.
Analysis of error type and frequency in apraxia of speech among Portuguese speakers.
Cera, Maysa Luchesi; Minett, Thaís Soares Cianciarullo; Ortiz, Karin Zazo
2010-01-01
Most studies characterizing errors in the speech of patients with apraxia involve English language. To analyze the types and frequency of errors produced by patients with apraxia of speech whose mother tongue was Brazilian Portuguese. 20 adults with apraxia of speech caused by stroke were assessed. The types of error committed by patients were analyzed both quantitatively and qualitatively, and frequencies compared. We observed the presence of substitution, omission, trial-and-error, repetition, self-correction, anticipation, addition, reiteration and metathesis, in descending order of frequency, respectively. Omission type errors were one of the most commonly occurring whereas addition errors were infrequent. These findings differed to those reported in English speaking patients, probably owing to differences in the methodologies used for classifying error types; the inclusion of speakers with apraxia secondary to aphasia; and the difference in the structure of Portuguese language to English in terms of syllable onset complexity and effect on motor control. The frequency of omission and addition errors observed differed to the frequency reported for speakers of English.
On the BER and capacity analysis of MIMO MRC systems with channel estimation error
Yang, Liang; Alouini, Mohamed-Slim
2011-01-01
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
SLC beam line error analysis using a model-based expert system
International Nuclear Information System (INIS)
Lee, M.; Kleban, S.
1988-02-01
Commissioning particle beam line is usually a very time-consuming and labor-intensive task for accelerator physicists. To aid in commissioning, we developed a model-based expert system that identifies error-free regions, as well as localizing beam line errors. This paper will give examples of the use of our system for the SLC commissioning. 8 refs., 5 figs
Analysis on two technologic errors of color separation grating used for ICF
International Nuclear Information System (INIS)
Chen Dewei; Li Yongping
2003-01-01
In this paper, the depth of color separation grating applied in ICF system is optimized firstly for good separating effect. After this, duty cycle error and the trapezoid structure are analyzed. A probable scope of technologic error that make the color separation grating have good effect is given in the end
CT for suspected appendicitis in children: an analysis of diagnostic errors
International Nuclear Information System (INIS)
Taylor, George A.; Callahan, Michael J.; Rodriguez, Diana; Smink, Douglas S.
2006-01-01
Mistakes have been made by the use of CT in diagnosing children with suspected appendicitis. Although others have reported the frequency of diagnostic errors, we were unable to find any studies that addressed the specific situations in which diagnostic errors occurred in children with suspected appendicitis. To investigate the frequency and type of diagnostic errors resulting from CT of children with suspected appendicitis when compared to surgical and pathological diagnosis. We reviewed imaging, clinical and pathological data on 1,207 consecutive pediatric patients who underwent CT examination for suspected appendicitis. Imaging findings were categorized as false-positive, false-negative, or indeterminate. Errors were classified as interpretative, technical or unavoidable. Concordance between surgical and pathological findings was also evaluated. The imaging findings of 34 patients (2.8%) were discrepant with the pathological examination or clinical follow-up. The errors in 23 cases were classified as interpretive (68%) and 11 as unavoidable (32%), and no errors were classified as technical. There were 23 false-positive errors (68%), 6 false-negative errors (18%), and 5 indeterminate imaging studies (15%). Isolated CT findings of an enlarged (greater than 6 mm) appendix, fat stranding, thickened bowel or non-visualization of the distal appendix were the most common false-positive CT findings. Of these 34 patients, 22 underwent appendectomy, with 10 (45%) having discordant surgical and pathological findings. (orig.)
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)
Error Consistency in Acquired Apraxia of Speech with Aphasia: Effects of the Analysis Unit
Haley, Katarina L.; Cunningham, Kevin T.; Eaton, Catherine Torrington; Jacks, Adam
2018-01-01
Purpose: Diagnostic recommendations for acquired apraxia of speech (AOS) have been contradictory concerning whether speech sound errors are consistent or variable. Studies have reported divergent findings that, on face value, could argue either for or against error consistency as a diagnostic criterion. The purpose of this study was to explain…
Wrong decisions in radiology. Analysis of causes and strategies for error prevention
International Nuclear Information System (INIS)
Lackner, Klaus-Juergen; Krug, Kathrin Barbara
2009-01-01
The book covers observations on errors concerning radiological decisions within a ten-year period. The compiled information is supposed to prevent similar errors in the future. The case studies cover the following issues: cranium, thorax, mamma, abdomen (liver, pancreas, colon), (gastrointestinal tract, urogenital tract), spinal cord, skeleton and blood vessels.
Error rates in forensic DNA analysis: Definition, numbers, impact and communication
Kloosterman, A.; Sjerps, M.; Quak, A.
2014-01-01
Forensic DNA casework is currently regarded as one of the most important types of forensic evidence, and important decisions in intelligence and justice are based on it. However, errors occasionally occur and may have very serious consequences. In other domains, error rates have been defined and
The common mode failures analysis of the redundent system with dependent human error
International Nuclear Information System (INIS)
Kim, M.K.; Chang, S.H.
1983-01-01
Common mode failures (CMFs) have been a serious concern in the nuclear power plant. Thereis a broad category of the failure mechanisms that can cause common mode failures. This paper is a theoretical investigation of the CMFs on the unavailability of the redundent system. It is assumed that the total CMFs consist of the potential CMFs and the dependent human error CMFs. As the human error dependency is higher, the total CMFs are more effected by the dependent human error. If the human error dependence is lower, the system unavailability strongly depends on the potential CMFs, rather than the mechanical failure or the dependent human error. And it is shown that the total CMFs are dominant factor to the unavailability of the redundent system. (Author)
The dose distribution and DVH change analysis wing to effect of the patient setup error
International Nuclear Information System (INIS)
Kim, Kyung Tae; Ju, Sang Gyu; Ahn, Jae Hong; Park, Young Hwan
2004-01-01
The setup error due to the patient and the staff from radiation treatment as the reason which is important the treatment record could be decided is a possibility of effect. The SET-UP ERROR of the patient analyzes the effect of dose distribution and DVH from radiation treatment of the patient. This test uses human phantom and when C-T scan doing, It rotated the Left direction of the human phantom and it made SET-UP ERROR, Standard plan and 3 mm, 5 mm, 7 mm, 10 mm, 15 mm, 20 mm with to distinguish, it made the C-T scan error. With the result, The SET-UP ERROR got each C-T image Using RTP equipment It used the plan which is used generally from clinical - Box plan, 3 Dimension plan( identical angle 5beam plan) Also, ( CTV+1cm margin, CTV+0.5cm margin, CTV+0.3,cm margin = PTV) it distinguished the standard plan and each set-up error plan and the plan used a dose distribution and the DVH and it analyzed. The Box 4 the plan and 3 Dimension plan which it bites it got similar an dose distribution and DVH in 3 mm, 5 mm From rotation error and Rectilinear movement (0%-2%). Rotation error and rectilinear error 7 mm, 10 mm, 15 mm, 20 mm appeared effect it will go mad to a enough change in treatment (2%-11%) The diminishes the effect of the SET-UP ERROR must reduce move with tension of the patient Also, we are important accessory development and the supply that it reducing of reproducibility and the move.
Energy Technology Data Exchange (ETDEWEB)
Kang, Daeil; Kim, J. H.; Jang, S. C
2007-03-15
Korea Atomic Energy Research Institute, using the ANS low power and shutdown (LPSD) probabilistic risk assessment (PRA) Standard, evaluated the LPSD PSA model of the KSNP, Yonggwang Units 5 and 6, and identified the items to be improved. The evaluation results of human reliability analysis (HRA) of the post-accident human errors in the LPSD PSA model for the KSNP showed that 10 items among 19 items of supporting requirements for those in the ANS PRA Standard were identified as them to be improved. Thus, we newly carried out a HRA for post-accident human errors in the LPSD PSA model for the KSNP. Following tasks are the improvements in the HRA of post-accident human errors of the LPSD PSA model for the KSNP compared with the previous one: Interviews with operators in the interpretation of the procedure, modeling of operator actions, and the quantification results of human errors, site visit. Applications of limiting value to the combined post-accident human errors. Documentation of information of all the input and bases for the detailed quantifications and the dependency analysis using the quantification sheets The assessment results for the new HRA results of post-accident human errors using the ANS LPSD PRA Standard show that above 80% items of its supporting requirements for post-accident human errors were graded as its Category II. The number of the re-estimated human errors using the LPSD Korea Standard HRA method is 385. Among them, the number of individual post-accident human errors is 253. The number of dependent post-accident human errors is 135. The quantification results of the LPSD PSA model for the KSNP with new HEPs show that core damage frequency (CDF) is increased by 5.1% compared with the previous baseline CDF It is expected that this study results will be greatly helpful to improve the PSA quality for the domestic nuclear power plants because they have sufficient PSA quality to meet the Category II of Supporting Requirements for the post
International Nuclear Information System (INIS)
Kang, Daeil; Kim, J. H.; Jang, S. C.
2007-03-01
Korea Atomic Energy Research Institute, using the ANS low power and shutdown (LPSD) probabilistic risk assessment (PRA) Standard, evaluated the LPSD PSA model of the KSNP, Yonggwang Units 5 and 6, and identified the items to be improved. The evaluation results of human reliability analysis (HRA) of the post-accident human errors in the LPSD PSA model for the KSNP showed that 10 items among 19 items of supporting requirements for those in the ANS PRA Standard were identified as them to be improved. Thus, we newly carried out a HRA for post-accident human errors in the LPSD PSA model for the KSNP. Following tasks are the improvements in the HRA of post-accident human errors of the LPSD PSA model for the KSNP compared with the previous one: Interviews with operators in the interpretation of the procedure, modeling of operator actions, and the quantification results of human errors, site visit. Applications of limiting value to the combined post-accident human errors. Documentation of information of all the input and bases for the detailed quantifications and the dependency analysis using the quantification sheets The assessment results for the new HRA results of post-accident human errors using the ANS LPSD PRA Standard show that above 80% items of its supporting requirements for post-accident human errors were graded as its Category II. The number of the re-estimated human errors using the LPSD Korea Standard HRA method is 385. Among them, the number of individual post-accident human errors is 253. The number of dependent post-accident human errors is 135. The quantification results of the LPSD PSA model for the KSNP with new HEPs show that core damage frequency (CDF) is increased by 5.1% compared with the previous baseline CDF It is expected that this study results will be greatly helpful to improve the PSA quality for the domestic nuclear power plants because they have sufficient PSA quality to meet the Category II of Supporting Requirements for the post
Operating personnel error analysis during operation failures in the Kozloduj NPP
International Nuclear Information System (INIS)
Jonkova, A.
1990-01-01
The failures due to personnel errors are analyzed for 10 years period (1977-1986). Most of the results are presented in absolute values and are considered in dynamics. The indices for relative shares are compared by alternative analysis. One of the most important causes is the fluctuation of manpower. The failures distribution by months within the year and by hours of the day is given. The biggest number of failures occurred in the period April-October (without August - the month of the leaves), when the refueling and repair were taken place, and in January-February, due to heavy meteorological conditions and some fatigue and disconcentration because of multiple holidays. The failures during the day shifts had the greatest relative share - 42%, during the afternoon shifts - 26% and during the night shifts - 32% The most 'dangerous' time periods happened to be 11-12 h and 13-14 h (deteriorated attention after lunch), 20-22 h (physiological drop of the psychological activity), 0-3 h (the lowest level of physiological and psychological activity) and in the first and last hours of every shift. Three groups of causes are pointed out as the most frequent: improper actions connected with orders; improper independent actions; uncoordinated teamwork. The following measures are proposed for reducing the effect of the human factor: setting up the training centre; preliminary evaluation of the professional qualification of the operators; current dynamic control of their neuro-psychological fitness and occupational reliability. 1 fig, 2 tabs, 5 refs
International Nuclear Information System (INIS)
Barriere, M.T.; Luckas, W.J.; Wreathall, J.; Cooper, S.E.; Bley, D.C.; Ramey-Smith, A.
1995-08-01
Since the early 1970s, human reliability analysis (HRA) has been considered to be an integral part of probabilistic risk assessments (PRAs). Nuclear power plant (NPP) events, from Three Mile Island through the mid-1980s, showed the importance of human performance to NPP risk. Recent events demonstrate that human performance continues to be a dominant source of risk. In light of these observations, the current limitations of existing HRA approaches become apparent when the role of humans is examined explicitly in the context of real NPP events. The development of new or improved HRA methodologies to more realistically represent human performance is recognized by the Nuclear Regulatory Commission (NRC) as a necessary means to increase the utility of PRAS. To accomplish this objective, an Improved HRA Project, sponsored by the NRC's Office of Nuclear Regulatory Research (RES), was initiated in late February, 1992, at Brookhaven National Laboratory (BNL) to develop an improved method for HRA that more realistically assesses the human contribution to plant risk and can be fully integrated with PRA. This report describes the research efforts including the development of a multidisciplinary HRA framework, the characterization and representation of errors of commission, and an approach for addressing human dependencies. The implications of the research and necessary requirements for further development also are discussed
Huan, Xun; Safta, Cosmin; Sargsyan, Khachik; Geraci, Gianluca; Eldred, Michael S.; Vane, Zachary P.; Lacaze, Guilhem; Oefelein, Joseph C.; Najm, Habib N.
2018-03-01
The development of scramjet engines is an important research area for advancing hypersonic and orbital flights. Progress toward optimal engine designs requires accurate flow simulations together with uncertainty quantification. However, performing uncertainty quantification for scramjet simulations is challenging due to the large number of uncertain parameters involved and the high computational cost of flow simulations. These difficulties are addressed in this paper by developing practical uncertainty quantification algorithms and computational methods, and deploying them in the current study to large-eddy simulations of a jet in crossflow inside a simplified HIFiRE Direct Connect Rig scramjet combustor. First, global sensitivity analysis is conducted to identify influential uncertain input parameters, which can help reduce the systems stochastic dimension. Second, because models of different fidelity are used in the overall uncertainty quantification assessment, a framework for quantifying and propagating the uncertainty due to model error is presented. These methods are demonstrated on a nonreacting jet-in-crossflow test problem in a simplified scramjet geometry, with parameter space up to 24 dimensions, using static and dynamic treatments of the turbulence subgrid model, and with two-dimensional and three-dimensional geometries.
Directory of Open Access Journals (Sweden)
Shaowei Ning
2017-01-01
Full Text Available The present study comprehensively analyzes error characteristics and performance of the two latest GPM-era satellite precipitation products over eastern China from April 2014 to March 2016. Analysis results indicate that the two products have totally different spatial distributions of total bias. Many of the underestimations for the GSMap-gauged could be traced to significant hit bias, with a secondary contribution from missed precipitation. For IMERG, total bias illustrates significant overestimation over most of the eastern part of China, except upper reaches of Yangtze and Yellow River basins. GSMap-gauged tends to overestimate light precipitation (<16 mm/day and underestimate precipitation with rain rate larger than 16 mm/day; however, IMERG underestimates precipitation at rain rate between 8 and 64 mm/day and overestimates precipitation at rain rate more than 64 mm/day. IMERG overestimates extreme precipitation indices (RR99P and R20TOT, with relative bias values of 17.9% and 11.5%, respectively. But GSMap-gauged shows significant underestimation of these indices. In addition, both products performed well in the Huaihe, Liaohe, and Yangtze River basins for extreme precipitation detection. At basin scale comparisons, the GSMap-gauged data has a relatively higher accuracy than IMERG, especially at the Haihe, Huaihe, Liaohe, and Yellow River basins.
Beragoui, Manel; Aguir, Chadlia; Khalfaoui, Mohamed; Enciso, Eduardo; Torralvo, Maria José; Duclaux, Laurent; Reinert, Laurence; Vayer, Marylène; Ben Lamine, Abdelmottaleb
2015-03-01
The present work involves the study of bovine serum albumin adsorption onto five functionalized polystyrene lattices. The adsorption measurements have been carried out using a quartz crystal microbalance. Poly(styrene-co-itaconic acid) was found to be an effective adsorbent for bovine serum albumin molecule adsorption. The experimental isotherm data were analyzed using theoretical models based on a statistical physics approach, namely monolayer, double layer with two successive energy levels, finite multilayer, and modified Brunauer-Emmet-Teller. The equilibrium data were then analyzed using five different non-linear error analysis methods and it was found that the finite multilayer model best describes the protein adsorption data. Surface characteristics, i.e., surface charge density and number density of surface carboxyl groups, were used to investigate their effect on the adsorption capacity. The combination of the results obtained from the number of adsorbed layers, the number of adsorbed molecules per site, and the thickness of the adsorbed bovine serum albumin layer allows us to predict that the adsorption of this protein molecule can also be distinguished by monolayer or multilayer adsorption with end-on, side-on, and overlap conformations. The magnitudes of the calculated adsorption energy indicate that bovine serum albumin molecules are physisorbed onto the adsorbent lattices.
Quantifying the predictive consequences of model error with linear subspace analysis
White, Jeremy T.; Doherty, John E.; Hughes, Joseph D.
2014-01-01
All computer models are simplified and imperfect simulators of complex natural systems. The discrepancy arising from simplification induces bias in model predictions, which may be amplified by the process of model calibration. This paper presents a new method to identify and quantify the predictive consequences of calibrating a simplified computer model. The method is based on linear theory, and it scales efficiently to the large numbers of parameters and observations characteristic of groundwater and petroleum reservoir models. The method is applied to a range of predictions made with a synthetic integrated surface-water/groundwater model with thousands of parameters. Several different observation processing strategies and parameterization/regularization approaches are examined in detail, including use of the Karhunen-Loève parameter transformation. Predictive bias arising from model error is shown to be prediction specific and often invisible to the modeler. The amount of calibration-induced bias is influenced by several factors, including how expert knowledge is applied in the design of parameterization schemes, the number of parameters adjusted during calibration, how observations and model-generated counterparts are processed, and the level of fit with observations achieved through calibration. Failure to properly implement any of these factors in a prediction-specific manner may increase the potential for predictive bias in ways that are not visible to the calibration and uncertainty analysis process.
Energy Technology Data Exchange (ETDEWEB)
Barriere, M.T.; Luckas, W.J. [Brookhaven National Lab., Upton, NY (United States); Wreathall, J. [Wreathall (John) and Co., Dublin, OH (United States); Cooper, S.E. [Science Applications International Corp., Reston, VA (United States); Bley, D.C. [PLG, Inc., Newport Beach, CA (United States); Ramey-Smith, A. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Technology
1995-08-01
Since the early 1970s, human reliability analysis (HRA) has been considered to be an integral part of probabilistic risk assessments (PRAs). Nuclear power plant (NPP) events, from Three Mile Island through the mid-1980s, showed the importance of human performance to NPP risk. Recent events demonstrate that human performance continues to be a dominant source of risk. In light of these observations, the current limitations of existing HRA approaches become apparent when the role of humans is examined explicitly in the context of real NPP events. The development of new or improved HRA methodologies to more realistically represent human performance is recognized by the Nuclear Regulatory Commission (NRC) as a necessary means to increase the utility of PRAS. To accomplish this objective, an Improved HRA Project, sponsored by the NRC`s Office of Nuclear Regulatory Research (RES), was initiated in late February, 1992, at Brookhaven National Laboratory (BNL) to develop an improved method for HRA that more realistically assesses the human contribution to plant risk and can be fully integrated with PRA. This report describes the research efforts including the development of a multidisciplinary HRA framework, the characterization and representation of errors of commission, and an approach for addressing human dependencies. The implications of the research and necessary requirements for further development also are discussed.
Energy Technology Data Exchange (ETDEWEB)
Huan, Xun [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Safta, Cosmin [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sargsyan, Khachik [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Geraci, Gianluca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eldred, Michael S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vane, Zachary P. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Lacaze, Guilhem [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Oefelein, Joseph C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Najm, Habib N. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2018-02-09
The development of scramjet engines is an important research area for advancing hypersonic and orbital flights. Progress toward optimal engine designs requires accurate flow simulations together with uncertainty quantification. However, performing uncertainty quantification for scramjet simulations is challenging due to the large number of uncertain parameters involved and the high computational cost of flow simulations. These difficulties are addressed in this paper by developing practical uncertainty quantification algorithms and computational methods, and deploying them in the current study to large-eddy simulations of a jet in crossflow inside a simplified HIFiRE Direct Connect Rig scramjet combustor. First, global sensitivity analysis is conducted to identify influential uncertain input parameters, which can help reduce the system’s stochastic dimension. Second, because models of different fidelity are used in the overall uncertainty quantification assessment, a framework for quantifying and propagating the uncertainty due to model error is presented. Finally, these methods are demonstrated on a nonreacting jet-in-crossflow test problem in a simplified scramjet geometry, with parameter space up to 24 dimensions, using static and dynamic treatments of the turbulence subgrid model, and with two-dimensional and three-dimensional geometries.
Positioning performance analysis of the time sum of arrival algorithm with error features
Gong, Feng-xun; Ma, Yan-qiu
2018-03-01
The theoretical positioning accuracy of multilateration (MLAT) with the time difference of arrival (TDOA) algorithm is very high. However, there are some problems in practical applications. Here we analyze the location performance of the time sum of arrival (TSOA) algorithm from the root mean square error ( RMSE) and geometric dilution of precision (GDOP) in additive white Gaussian noise (AWGN) environment. The TSOA localization model is constructed. Using it, the distribution of location ambiguity region is presented with 4-base stations. And then, the location performance analysis is started from the 4-base stations with calculating the RMSE and GDOP variation. Subsequently, when the location parameters are changed in number of base stations, base station layout and so on, the performance changing patterns of the TSOA location algorithm are shown. So, the TSOA location characteristics and performance are revealed. From the RMSE and GDOP state changing trend, the anti-noise performance and robustness of the TSOA localization algorithm are proved. The TSOA anti-noise performance will be used for reducing the blind-zone and the false location rate of MLAT systems.
Measurement-based analysis of error latency. [in computer operating system
Chillarege, Ram; Iyer, Ravishankar K.
1987-01-01
This paper demonstrates a practical methodology for the study of error latency under a real workload. The method is illustrated with sampled data on the physical memory activity, gathered by hardware instrumentation on a VAX 11/780 during the normal workload cycle of the installation. These data are used to simulate fault occurrence and to reconstruct the error discovery process in the system. The technique provides a means to study the system under different workloads and for multiple days. An approach to determine the percentage of undiscovered errors is also developed and a verification of the entire methodology is performed. This study finds that the mean error latency, in the memory containing the operating system, varies by a factor of 10 to 1 (in hours) between the low and high workloads. It is found that of all errors occurring within a day, 70 percent are detected in the same day, 82 percent within the following day, and 91 percent within the third day. The increase in failure rate due to latency is not so much a function of remaining errors but is dependent on whether or not there is a latent error.
Directory of Open Access Journals (Sweden)
Marek Rejman
2013-03-01
Full Text Available 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
Directory of Open Access Journals (Sweden)
Jun Yang
2014-01-01
Full Text Available To improve the CNC machine tools precision, a thermal error modeling for the motorized spindle was proposed based on time series analysis, considering the length of cutting tools and thermal declined angles, and the real-time error compensation was implemented. A five-point method was applied to measure radial thermal declinations and axial expansion of the spindle with eddy current sensors, solving the problem that the three-point measurement cannot obtain the radial thermal angle errors. Then the stationarity of the thermal error sequences was determined by the Augmented Dickey-Fuller Test Algorithm, and the autocorrelation/partial autocorrelation function was applied to identify the model pattern. By combining both Yule-Walker equations and information criteria, the order and parameters of the models were solved effectively, which improved the prediction accuracy and generalization ability. The results indicated that the prediction accuracy of the time series model could reach up to 90%. In addition, the axial maximum error decreased from 39.6 μm to 7 μm after error compensation, and the machining accuracy was improved by 89.7%. Moreover, the X/Y-direction accuracy can reach up to 77.4% and 86%, respectively, which demonstrated that the proposed methods of measurement, modeling, and compensation were effective.
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...
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
Error Analysis and Calibration Method of a Multiple Field-of-View Navigation System.
Shi, Shuai; Zhao, Kaichun; You, Zheng; Ouyang, Chenguang; Cao, Yongkui; Wang, Zhenzhou
2017-03-22
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 novel method based on the geometrical constraints in object space, called checkerboard-fixed post-processing calibration (CPC), is proposed to solve the problem of simultaneously obtaining the intrinsic parameters of the cameras integrated in the MFNS and the transformation between the MFNS coordinate and the cameras' coordinates. This method utilizes a two-axis turntable and a prior alignment of the coordinates is needed. Theoretical derivation and practical operation of the CPC method are introduced. The calibration experiment results of the MFNS indicate that the extrinsic parameter accuracy of the CPC reaches 0.1° for each Euler angle and 0.6 mm for each position vector component (1σ). A navigation experiment verifies the calibration result and the performance of the MFNS. The MFNS is found to work properly, and the accuracy of the position vector components and Euler angle reaches 1.82 mm and 0.17° (1σ) respectively. The basic mechanism of the MFNS may be utilized as a reference for the design and analysis of multiple-camera systems. Moreover, the calibration method proposed has practical value for its convenience for use and potential for integration into a toolkit.
Directory of Open Access Journals (Sweden)
David M Williams
Full Text Available Advances in animal tracking technologies have reduced but not eliminated positional error. While aware of such inherent error, scientists often proceed with analyses that assume exact locations. The results of such analyses then represent one realization in a distribution of possible outcomes. Evaluating results within the context of that distribution can strengthen or weaken our confidence in conclusions drawn from the analysis in question. We evaluated the habitat-specific positional error of stationary GPS collars placed under a range of vegetation conditions that produced a gradient of canopy cover. We explored how variation of positional error in different vegetation cover types affects a researcher's ability to discern scales of movement in analyses of first-passage time for white-tailed deer (Odocoileus virginianus. We placed 11 GPS collars in 4 different vegetative canopy cover types classified as the proportion of cover above the collar (0-25%, 26-50%, 51-75%, and 76-100%. We simulated the effect of positional error on individual movement paths using cover-specific error distributions at each location. The different cover classes did not introduce any directional bias in positional observations (1 m≤mean≤6.51 m, 0.24≤p≤0.47, but the standard deviation of positional error of fixes increased significantly with increasing canopy cover class for the 0-25%, 26-50%, 51-75% classes (SD = 2.18 m, 3.07 m, and 4.61 m, respectively and then leveled off in the 76-100% cover class (SD = 4.43 m. We then added cover-specific positional errors to individual deer movement paths and conducted first-passage time analyses on the noisy and original paths. First-passage time analyses were robust to habitat-specific error in a forest-agriculture landscape. For deer in a fragmented forest-agriculture environment, and species that move across similar geographic extents, we suggest that first-passage time analysis is robust with regard to
National Research Council Canada - National Science Library
Pfleiderer, Elaine M; Scroggins, Cheryl L; Manning, Carol A
2009-01-01
Two separate logistic regression analyses were conducted for low- and high-altitude sectors to determine whether a set of dynamic sector characteristics variables could reliably discriminate between operational error (OE...
Sinha, Samiran; Mallick, Bani K.; Kipnis, Victor; Carroll, Raymond J.
2009-01-01
We propose a semiparametric Bayesian method for handling measurement error in nutritional epidemiological data. Our goal is to estimate nonparametrically the form of association between a disease and exposure variable while the true values
Time-discrete higher order ALE formulations: a priori error analysis
Bonito, Andrea; Kyza, Irene; Nochetto, Ricardo H.
2013-01-01
We derive optimal a priori error estimates for discontinuous Galerkin (dG) time discrete schemes of any order applied to an advection-diffusion model defined on moving domains and written in the Arbitrary Lagrangian Eulerian (ALE) framework. Our
The accuracy of webcams in 2D motion analysis: sources of error and their control
International Nuclear Information System (INIS)
Page, A; Candelas, P; Belmar, F; Moreno, R
2008-01-01
In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost
The accuracy of webcams in 2D motion analysis: sources of error and their control
Energy Technology Data Exchange (ETDEWEB)
Page, A; Candelas, P; Belmar, F [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Valencia (Spain); Moreno, R [Instituto de Biomecanica de Valencia, Valencia (Spain)], E-mail: alvaro.page@ibv.upv.es
2008-07-15
In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost.
Saccades to remembered target locations: an analysis of systematic and variable errors.
White, J M; Sparks, D L; Stanford, T R
1994-01-01
We studied the effects of varying delay interval on the accuracy and velocity of saccades to the remembered locations of visual targets. Remembered saccades were less accurate than control saccades. Both systematic and variable errors contributed to the loss of accuracy. Systematic errors were similar in size for delay intervals ranging from 400 msec to 5.6 sec, but variable errors increased monotonically as delay intervals were lengthened. Compared to control saccades, remembered saccades were slower and the peak velocities were more variable. However, neither peak velocity nor variability in peak velocity was related to the duration of the delay interval. Our findings indicate that a memory-related process is not the major source of the systematic errors observed on memory trials.
Analysis of errors during medical and computerized diagnostics of spherical lung neoplasms
International Nuclear Information System (INIS)
Pozmogov, A.I.; Petruk, D.A.
1985-01-01
Reasons for errors in medical and computerized diagnostics of spherical lung neoplasms are studied based on material of 212 case records and clinicoroentgenological data; it should promote improvement of their diagnostics
Human Error and General Aviation Accidents: A Comprehensive, Fine-Grained Analysis Using HFACS
National Research Council Canada - National Science Library
Wiegmann, Douglas; Faaborg, Troy; Boquet, Albert; Detwiler, Cristy; Holcomb, Kali; Shappell, Scott
2005-01-01
... of both commercial and general aviation (GA) accidents. These analyses have helped to identify general trends in the types of human factors issues and aircrew errors that have contributed to civil aviation accidents...
Error analysis in Fourier methods for option pricing for exponential Lévy processes
Crocce, Fabian; Hä ppö lä , Juho; Keissling, Jonas; Tempone, Raul
2015-01-01
We derive an error bound for utilising the discrete Fourier transform method for solving Partial Integro-Differential Equations (PIDE) that describe european option prices for exponential Lévy driven asset prices. We give sufficient conditions
Statistical analysis of lifetime determinations in the presence of large errors
International Nuclear Information System (INIS)
Yost, G.P.
1984-01-01
The lifetimes of the new particles are very short, and most of the experiments which measure decay times are subject to measurement errors which are not negligible compared with the decay times themselves. Bartlett has analyzed the problem of lifetime estimation if the error on each event is small or zero. For the case of non-negligible measurement errors, σsub(i), on each event, we are interested in a few basic questions: How well does maximum likelihood work. That is, (a) are the errors reasonable, (b) is the answer unbiased, and (c) are there other estimators with superior performance. We concentrate on the results of our Monte Carlo investigation for the case in which the experiment is sensitive over all times -infinity< xsub(i)< infinity
The design and analysis of single flank transmission error testor for loaded gears
Houser, D. R.; Bassett, D. E.
1985-01-01
Due to geometrical imperfections in gears and finite tooth stiffnesses, the motion transmitted from an input gear shaft to an output gear shaft will not have conjugate action. In order to strengthen the understanding of transmission error and to verify mathematical models of gear transmission error, a test stand that will measure the transmission error of a gear pair at operating loads, but at reduced speeds would be desirable. This document describes the design and development of a loaded transmission error tester. For a gear box with a gear ratio of one, few tooth meshing combinations will occur during a single test. In order to observe the effects of different tooth mesh combinations and to increase the ability to load test gear pairs with higher gear ratios, the system was designed around a gear box with a gear ratio of two.
Cause analysis and preventives for human error events in Daya Bay NPP
International Nuclear Information System (INIS)
Huang Weigang; Zhang Li
1998-01-01
Daya Bay Nuclear Power Plant is put into commercial operation in 1994 Until 1996, there are 368 human error events in operating and maintenance area, occupying 39% of total events. These events occurred mainly in the processes of maintenance, test equipment isolation and system on-line, in particular in refuelling and maintenance. The author analyses root causes for human errorievents, which are mainly operator omission or error procedure deficiency; procedure not followed; lack of training; communication failures; work management inadequacy. The protective measures and treatment principle for human error events are also discussed, and several examples applying them are given. Finally, it is put forward that key to prevent human error event lies in the coordination and management, person in charge of work, and good work habits of staffs
Error rates in forensic DNA analysis: definition, numbers, impact and communication.
Kloosterman, Ate; Sjerps, Marjan; Quak, Astrid
2014-09-01
Forensic DNA casework is currently regarded as one of the most important types of forensic evidence, and important decisions in intelligence and justice are based on it. However, errors occasionally occur and may have very serious consequences. In other domains, error rates have been defined and published. The forensic domain is lagging behind concerning this transparency for various reasons. In this paper we provide definitions and observed frequencies for different types of errors at the Human Biological Traces Department of the Netherlands Forensic Institute (NFI) over the years 2008-2012. Furthermore, we assess their actual and potential impact and describe how the NFI deals with the communication of these numbers to the legal justice system. We conclude that the observed relative frequency of quality failures is comparable to studies from clinical laboratories and genetic testing centres. Furthermore, this frequency is constant over the five-year study period. The most common causes of failures related to the laboratory process were contamination and human error. Most human errors could be corrected, whereas gross contamination in crime samples often resulted in irreversible consequences. Hence this type of contamination is identified as the most significant source of error. Of the known contamination incidents, most were detected by the NFI quality control system before the report was issued to the authorities, and thus did not lead to flawed decisions like false convictions. However in a very limited number of cases crucial errors were detected after the report was issued, sometimes with severe consequences. Many of these errors were made in the post-analytical phase. The error rates reported in this paper are useful for quality improvement and benchmarking, and contribute to an open research culture that promotes public trust. However, they are irrelevant in the context of a particular case. Here case-specific probabilities of undetected errors are needed
DEFF Research Database (Denmark)
Rabøl, Louise Isager; Andersen, Mette Lehmann; Østergaard, Doris
2011-01-01
incidents. The objective of this study is to review RCA reports (RCAR) for characteristics of verbal communication errors between hospital staff in an organisational perspective. Method Two independent raters analysed 84 RCARs, conducted in six Danish hospitals between 2004 and 2006, for descriptions......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...
Kuselman, Ilya; Pennecchi, Francesca; Epstein, Malka; Fajgelj, Ales; Ellison, Stephen L R
2014-12-01
Monte Carlo simulation of expert judgments on human errors in a chemical analysis was used for determination of distributions of the error quantification scores (scores of likelihood and severity, and scores of effectiveness of a laboratory quality system in prevention of the errors). The simulation was based on modeling of an expert behavior: confident, reasonably doubting and irresolute expert judgments were taken into account by means of different probability mass functions (pmfs). As a case study, 36 scenarios of human errors which may occur in elemental analysis of geological samples by ICP-MS were examined. Characteristics of the score distributions for three pmfs of an expert behavior were compared. Variability of the scores, as standard deviation of the simulated score values from the distribution mean, was used for assessment of the score robustness. A range of the score values, calculated directly from elicited data and simulated by a Monte Carlo method for different pmfs, was also discussed from the robustness point of view. It was shown that robustness of the scores, obtained in the case study, can be assessed as satisfactory for the quality risk management and improvement of a laboratory quality system against human errors. Copyright © 2014 Elsevier B.V. All rights reserved.
Multipole error analysis using local 3-bump orbit data in Fermilab Recycler
International Nuclear Information System (INIS)
Yang, M.J.; Xiao, M.
2005-01-01
The magnetic harmonic errors of the Fermilab Recycler ring were examined using circulating beam data taken with closed local orbit bumps. Data was first parsed into harmonic orbits of first, second, and third order. Each of which was analyzed for sources of magnetic errors of corresponding order. This study was made possible only with the incredible resolution of a new BPM system that was commissioned after June of 2003
An Analysis of Students Error in Solving PISA 2012 and Its Scaffolding
Sari, Yurizka Melia; Valentino, Erik
2016-01-01
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 PI...
Semenov, Z. V.; Labusov, V. A.
2017-11-01
Results of studying the errors of indirect monitoring by means of computer simulations are reported. The monitoring method is based on measuring spectra of reflection from additional monitoring substrates in a wide spectral range. Special software (Deposition Control Simulator) is developed, which allows one to estimate the influence of the monitoring system parameters (noise of the photodetector array, operating spectral range of the spectrometer and errors of its calibration in terms of wavelengths, drift of the radiation source intensity, and errors in the refractive index of deposited materials) on the random and systematic errors of deposited layer thickness measurements. The direct and inverse problems of multilayer coatings are solved using the OptiReOpt library. Curves of the random and systematic errors of measurements of the deposited layer thickness as functions of the layer thickness are presented for various values of the system parameters. Recommendations are given on using the indirect monitoring method for the purpose of reducing the layer thickness measurement error.
Local blur analysis and phase error correction method for fringe projection profilometry systems.
Rao, Li; Da, Feipeng
2018-05-20
We introduce a flexible error correction method for fringe projection profilometry (FPP) systems in the presence of local blur phenomenon. Local blur caused by global light transport such as camera defocus, projector defocus, and subsurface scattering will cause significant systematic errors in FPP systems. Previous methods, which adopt high-frequency patterns to separate the direct and global components, fail when the global light phenomenon occurs locally. In this paper, the influence of local blur on phase quality is thoroughly analyzed, and a concise error correction method is proposed to compensate the phase errors. For defocus phenomenon, this method can be directly applied. With the aid of spatially varying point spread functions and local frontal plane assumption, experiments show that the proposed method can effectively alleviate the system errors and improve the final reconstruction accuracy in various scenes. For a subsurface scattering scenario, if the translucent object is dominated by multiple scattering, the proposed method can also be applied to correct systematic errors once the bidirectional scattering-surface reflectance distribution function of the object material is measured.
Nevo, Daniel; Zucker, David M; Tamimi, Rulla M; Wang, Molin
2016-12-30
A common paradigm in dealing with heterogeneity across tumors in cancer analysis is to cluster the tumors into subtypes using marker data on the tumor, and then to analyze each of the clusters separately. A more specific target is to investigate the association between risk factors and specific subtypes and to use the results for personalized preventive treatment. This task is usually carried out in two steps-clustering and risk factor assessment. However, two sources of measurement error arise in these problems. The first is the measurement error in the biomarker values. The second is the misclassification error when assigning observations to clusters. We consider the case with a specified set of relevant markers and propose a unified single-likelihood approach for normally distributed biomarkers. As an alternative, we consider a two-step procedure with the tumor type misclassification error taken into account in the second-step risk factor analysis. We describe our method for binary data and also for survival analysis data using a modified version of the Cox model. We present asymptotic theory for the proposed estimators. Simulation results indicate that our methods significantly lower the bias with a small price being paid in terms of variance. We present an analysis of breast cancer data from the Nurses' Health Study to demonstrate the utility of our method. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
A model-based and computer-aided approach to analysis of human errors in nuclear power plants
International Nuclear Information System (INIS)
Yoon, Wan C.; Lee, Yong H.; Kim, Young S.
1996-01-01
Since the operator's mission in NPPs is increasingly defined by cognitive tasks such as monitoring, diagnosis and planning, the focus of human error analysis should also move from external actions to internal decision-making processes. While more elaborate analysis of cognitive aspects of human errors will help understand their causes and derive effective countermeasures, a lack of framework and an arbitrary resolution of description may hamper the effectiveness of such analysis. This paper presents new model-based schemes of event description and error classification as well as an interactive computerized support system. The schemes and the support system were produced in an effort to develop an improved version of HPES. The use of a decision-making model enables the analyst to document cognitive aspects of human performance explicitly and in a proper resolution. The stage-specific terms used in the proposed schemes make the task of characterizing human errors easier and confident for field analysts. The support system was designed to help the analyst achieve a contextually well-integrated analysis throughout the different parts of HPES
Through the comparison of several regional-scale chemistry transport modelling systems that simulate meteorology and air quality over the European and American continents, this study aims at i) apportioning the error to the responsible processes using time-scale analysis, ii) hel...
Taha, Haitham; Ibrahim, Raphiq; Khateb, Asaid
2014-01-01
The dominant error types were investigated as a function of phonological processing (PP) deficit severity in four groups of impaired readers. For this aim, an error analysis paradigm distinguishing between four error types was used. The findings revealed that the different types of impaired readers were characterized by differing predominant error…
Directory of Open Access Journals (Sweden)
Jeane Barcelos Soriano
2007-12-01
and generate an increasing search for better professional education and responsibility for tasks specifi c to the area, as well as a concern with the ethical factors of professional intervention in physical education. The purpose of this study was to understand how physical education professionals describe and interpret the consequences of their professional intervention, based on the error perspective. Information was obtained by means of a semi-structure interview, conducted with 11 professionals who were not part of the school system, and who had 7 – 25 years of professional education. The data treatment followed the characteristics of the content analysis, establishing later the analysis categories, namely: 1 Academic Education and Professional Identity, which includes the characteristics and circumstances of professional education, identity and culture and 2 Professional intervention and Accreditation, which includes aspects connected to professional legitimacy and the accreditation process. This study allowed us to consider that, while Physical Education professionals are concerned with the quality of the services offered in the area, they do not clearly defi ne what constitutes a professional error in the area, and neither do they evaluate the consequences of their professional intervention based on this perspective.
Errors in accident data, its types, causes and methods of rectification-analysis of the literature.
Ahmed, Ashar; Sadullah, Ahmad Farhan Mohd; Yahya, Ahmad Shukri
2017-07-29
Most of the decisions taken to improve road safety are based on accident data, which makes it the back bone of any country's road safety system. Errors in this data will lead to misidentification of black spots and hazardous road segments, projection of false estimates pertinent to accidents and fatality rates, and detection of wrong parameters responsible for accident occurrence, thereby making the entire road safety exercise ineffective. Its extent varies from country to country depending upon various factors. Knowing the type of error in the accident data and the factors causing it enables the application of the correct method for its rectification. Therefore there is a need for a systematic literature review that addresses the topic at a global level. This paper fulfils the above research gap by providing a synthesis of literature for the different types of errors found in the accident data of 46 countries across the six regions of the world. The errors are classified and discussed with respect to each type and analysed with respect to income level; assessment with regard to the magnitude for each type is provided; followed by the different causes that result in their occurrence, and the various methods used to address each type of error. Among high-income countries the extent of error in reporting slight, severe, non-fatal and fatal injury accidents varied between 39-82%, 16-52%, 12-84%, and 0-31% respectively. For middle-income countries the error for the same categories varied between 93-98%, 32.5-96%, 34-99% and 0.5-89.5% respectively. The only four studies available for low-income countries showed that the error in reporting non-fatal and fatal accidents varied between 69-80% and 0-61% respectively. The logistic relation of error in accident data reporting, dichotomised at 50%, indicated that as the income level of a country increases the probability of having less error in accident data also increases. Average error in recording information related to the
Analysis of Point Based Image Registration Errors With Applications in Single Molecule Microscopy.
Cohen, E A K; Ober, R J
2013-12-15
We present an asymptotic treatment of errors involved in point-based image registration where control point (CP) localization is subject to heteroscedastic noise; a suitable model for image registration in fluorescence microscopy. Assuming an affine transform, CPs are used to solve a multivariate regression problem. With measurement errors existing for both sets of CPs this is an errors-in-variable problem and linear least squares is inappropriate; the correct method being generalized least squares. To allow for point dependent errors the equivalence of a generalized maximum likelihood and heteroscedastic generalized least squares model is achieved allowing previously published asymptotic results to be extended to image registration. For a particularly useful model of heteroscedastic noise where covariance matrices are scalar multiples of a known matrix (including the case where covariance matrices are multiples of the identity) we provide closed form solutions to estimators and derive their distribution. We consider the target registration error (TRE) and define a new measure called the localization registration error (LRE) believed to be useful, especially in microscopy registration experiments. Assuming Gaussianity of the CP localization errors, it is shown that the asymptotic distribution for the TRE and LRE are themselves Gaussian and the parameterized distributions are derived. Results are successfully applied to registration in single molecule microscopy to derive the key dependence of the TRE and LRE variance on the number of CPs and their associated photon counts. Simulations show asymptotic results are robust for low CP numbers and non-Gaussianity. The method presented here is shown to outperform GLS on real imaging data.
CO2 production in animals: analysis of potential errors in the doubly labeled water method
International Nuclear Information System (INIS)
Nagy, K.A.
1979-03-01
Laboratory validation studies indicate that doubly labeled water ( 3 HH 18 O and 2 HH 18 O) measurements of CO 2 production are accurate to within +-9% in nine species of mammals and reptiles, a bird, and an insect. However, in field studies, errors can be much larger under certain circumstances. Isotopic fraction of labeled water can cause large errors in animals whose evaporative water loss comprises a major proportion of total water efflux. Input of CO 2 across lungs and skin caused errors exceeding +80% in kangaroo rats exposed to air containing 3.4% unlabeled CO 2 . Analytical errors of +-1% in isotope concentrations can cause calculated rates of CO 2 production to contain errors exceeding +-70% in some circumstances. These occur: 1) when little decline in isotope concentractions has occured during the measurement period; 2) when final isotope concentrations closely approach background levels; and 3) when the rate of water flux in an animal is high relative to its rate of CO 2 production. The following sources of error are probably negligible in most situations: 1) use of an inappropriate equation for calculating CO 2 production, 2) variations in rates of water or CO 2 flux through time, 3) use of H 2 O-18 dilution space as a measure of body water volume, 4) exchange of 0-18 between water and nonaqueous compounds in animals (including excrement), 5) incomplete mixing of isotopes in the animal, and 6) input of unlabeled water via lungs and skin. Errors in field measurements of CO 2 production can be reduced to acceptable levels (< 10%) by appropriate selection of study subjects and recapture intervals
Learning from errors: analysis of medication order voiding in CPOE systems.
Kannampallil, Thomas G; Abraham, Joanna; Solotskaya, Anna; Philip, Sneha G; Lambert, Bruce L; Schiff, Gordon D; Wright, Adam; Galanter, William L
2017-07-01
Medication order voiding allows clinicians to indicate that an existing order was placed in error. We explored whether the order voiding function could be used to record and study medication ordering errors. We examined medication orders from an academic medical center for a 6-year period (2006-2011; n = 5 804 150). We categorized orders based on status (void, not void) and clinician-provided reasons for voiding. We used multivariable logistic regression to investigate the association between order voiding and clinician, patient, and order characteristics. We conducted chart reviews on a random sample of voided orders ( n = 198) to investigate the rate of medication ordering errors among voided orders, and the accuracy of clinician-provided reasons for voiding. We found that 0.49% of all orders were voided. Order voiding was associated with clinician type (physician, pharmacist, nurse, student, other) and order type (inpatient, prescription, home medications by history). An estimated 70 ± 10% of voided orders were due to medication ordering errors. Clinician-provided reasons for voiding were reasonably predictive of the actual cause of error for duplicate orders (72%), but not for other reasons. Medication safety initiatives require availability of error data to create repositories for learning and training. The voiding function is available in several electronic health record systems, so order voiding could provide a low-effort mechanism for self-reporting of medication ordering errors. Additional clinician training could help increase the quality of such reporting. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com
Directory of Open Access Journals (Sweden)
Sean Patrick Clifford MD
2016-05-01
Full Text Available A 28-year-old man presented emergently to the operating room following a gun-shot injury to his right groin. Our hospital’s Massive Transfusion Protocol was initiated as the patient entered the operating room actively hemorrhaging and severely hypotensive. During the aggressive resuscitation efforts, the patient was inadvertently transfused 2 units of packed red blood cells intended for another patient due to a series of errors. Fortunately, the incorrect product was compatible, and the patient recovered from his near-fatal injuries. Root cause analysis was used to review the transfusion error and develop an action plan to help prevent future occurrences.
Clifford, Sean Patrick; Mick, Paul Brian; Derhake, Brian Matthew
2016-01-01
A 28-year-old man presented emergently to the operating room following a gun-shot injury to his right groin. Our hospital's Massive Transfusion Protocol was initiated as the patient entered the operating room actively hemorrhaging and severely hypotensive. During the aggressive resuscitation efforts, the patient was inadvertently transfused 2 units of packed red blood cells intended for another patient due to a series of errors. Fortunately, the incorrect product was compatible, and the patient recovered from his near-fatal injuries. Root cause analysis was used to review the transfusion error and develop an action plan to help prevent future occurrences.
A method for the estimation of the residual error in the SALP approach for fault tree analysis
International Nuclear Information System (INIS)
Astolfi, M.; Contini, S.
1980-01-01
The aim of this report is the illustration of the algorithms implemented in the SALP-MP code for the estimation of the residual error. These algorithms are of more general use, and it would be possible to implement them on all codes of the series SALP previously developed, as well as, with minor modifications, to analysis procedures based on 'top-down' approaches. At the time, combined 'top-down' - 'bottom up' procedures are being studied in order to take advantage from both approaches for further reduction of computer time and better estimation of the residual error, for which the developed algorithms are still applicable
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.
Pan, B.
2016-03-22
Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work. © 2016 Elsevier Ltd. All rights reserved.
Bhargava, K.; Kalnay, E.; Carton, J.; Yang, F.
2017-12-01
Systematic forecast errors, arising from model deficiencies, form a significant portion of the total forecast error in weather prediction models like the Global Forecast System (GFS). While much effort has been expended to improve models, substantial model error remains. The aim here is to (i) estimate the model deficiencies in the GFS that lead to systematic forecast errors, (ii) implement an online correction (i.e., within the model) scheme to correct GFS following the methodology of Danforth et al. [2007] and Danforth and Kalnay [2008, GRL]. Analysis Increments represent the corrections that new observations make on, in this case, the 6-hr forecast in the analysis cycle. Model bias corrections are estimated from the time average of the analysis increments divided by 6-hr, assuming that initial model errors grow linearly and first ignoring the impact of observation bias. During 2012-2016, seasonal means of the 6-hr model bias are generally robust despite changes in model resolution and data assimilation systems, and their broad continental scales explain their insensitivity to model resolution. The daily bias dominates the sub-monthly analysis increments and consists primarily of diurnal and semidiurnal components, also requiring a low dimensional correction. Analysis increments in 2015 and 2016 are reduced over oceans, which is attributed to improvements in the specification of the SSTs. These results encourage application of online correction, as suggested by Danforth and Kalnay, for mean, seasonal and diurnal and semidiurnal model biases in GFS to reduce both systematic and random errors. As the error growth in the short-term is still linear, estimated model bias corrections can be added as a forcing term in the model tendency equation to correct online. Preliminary experiments with GFS, correcting temperature and specific humidity online show reduction in model bias in 6-hr forecast. This approach can then be used to guide and optimize the design of sub
Clarke, William L; Anderson, Stacey; Farhy, Leon; Breton, Marc; Gonder-Frederick, Linda; Cox, Daniel; Kovatchev, Boris
2005-10-01
To compare the clinical accuracy of two different continuous glucose sensors (CGS) during euglycemia and hypoglycemia using continuous glucose-error grid analysis (CG-EGA). FreeStyle Navigator (Abbott Laboratories, Alameda, CA) and MiniMed CGMS (Medtronic, Northridge, CA) CGSs were applied to the abdomens of 16 type 1 diabetic subjects (age 42 +/- 3 years) 12 h before the initiation of the study. Each system was calibrated according to the manufacturer's recommendations. Each subject underwent a hyperinsulinemic-euglycemic clamp (blood glucose goal 110 mg/dl) for 70-210 min followed by a 1-mg.dl(-1).min(-1) controlled reduction in blood glucose toward a nadir of 40 mg/dl. Arterialized blood glucose was determined every 5 min using a Beckman Glucose Analyzer (Fullerton, CA). CGS glucose recordings were matched to the reference blood glucose with 30-s precision, and rates of glucose change were calculated for 5-min intervals. CG-EGA was used to quantify the clinical accuracy of both systems by estimating combined point and rate accuracy of each system in the euglycemic (70-180 mg/dl) and hypoglycemic (<70 mg/dl) ranges. A total of 1,104 data pairs were recorded in the euglycemic range and 250 data pairs in the hypoglycemic range. Overall correlation between CGS and reference glucose was similar for both systems (Navigator, r = 0.84; CGMS, r = 0.79, NS). During euglycemia, both CGS systems had similar clinical accuracy (Navigator zones A + B, 88.8%; CGMS zones A + B, 89.3%, NS). However, during hypoglycemia, the Navigator was significantly more clinically accurate than the CGMS (zones A + B = 82.4 vs. 61.6%, Navigator and CGMS, respectively, P < 0.0005). CG-EGA is a helpful tool for evaluating and comparing the clinical accuracy of CGS systems in different blood glucose ranges. CG-EGA provides accuracy details beyond other methods of evaluation, including correlational analysis and the original EGA.
Testolin, C G; Gore, R; Rivkin, T; Horlick, M; Arbo, J; Wang, Z; Chiumello, G; Heymsfield, S B
2000-12-01
Dual-energy X-ray absorptiometry (DXA) percent (%) fat estimates may be inaccurate in young children, who typically have high tissue hydration levels. This study was designed to provide a comprehensive analysis of pediatric tissue hydration effects on DXA %fat estimates. Phase 1 was experimental and included three in vitro studies to establish the physical basis of DXA %fat-estimation models. Phase 2 extended phase 1 models and consisted of theoretical calculations to estimate the %fat errors emanating from previously reported pediatric hydration effects. Phase 1 experiments supported the two-compartment DXA soft tissue model and established that pixel ratio of low to high energy (R values) are a predictable function of tissue elemental content. In phase 2, modeling of reference body composition values from birth to age 120 mo revealed that %fat errors will arise if a "constant" adult lean soft tissue R value is applied to the pediatric population; the maximum %fat error, approximately 0.8%, would be present at birth. High tissue hydration, as observed in infants and young children, leads to errors in DXA %fat estimates. The magnitude of these errors based on theoretical calculations is small and may not be of clinical or research significance.
Hallez, Hans; Staelens, Steven; Lemahieu, Ignace
2009-10-01
EEG source analysis is a valuable tool for brain functionality research and for diagnosing neurological disorders, such as epilepsy. It requires a geometrical representation of the human head or a head model, which is often modeled as an isotropic conductor. However, it is known that some brain tissues, such as the skull or white matter, have an anisotropic conductivity. Many studies reported that the anisotropic conductivities have an influence on the calculated electrode potentials. However, few studies have assessed the influence of anisotropic conductivities on the dipole estimations. In this study, we want to determine the dipole estimation errors due to not taking into account the anisotropic conductivities of the skull and/or brain tissues. Therefore, head models are constructed with the same geometry, but with an anisotropically conducting skull and/or brain tissue compartment. These head models are used in simulation studies where the dipole location and orientation error is calculated due to neglecting anisotropic conductivities of the skull and brain tissue. Results show that not taking into account the anisotropic conductivities of the skull yields a dipole location error between 2 and 25 mm, with an average of 10 mm. When the anisotropic conductivities of the brain tissues are neglected, the dipole location error ranges between 0 and 5 mm. In this case, the average dipole location error was 2.3 mm. In all simulations, the dipole orientation error was smaller than 10°. We can conclude that the anisotropic conductivities of the skull have to be incorporated to improve the accuracy of EEG source analysis. The results of the simulation, as presented here, also suggest that incorporation of the anisotropic conductivities of brain tissues is not necessary. However, more studies are needed to confirm these suggestions.
International Nuclear Information System (INIS)
Hallez, Hans; Staelens, Steven; Lemahieu, Ignace
2009-01-01
EEG source analysis is a valuable tool for brain functionality research and for diagnosing neurological disorders, such as epilepsy. It requires a geometrical representation of the human head or a head model, which is often modeled as an isotropic conductor. However, it is known that some brain tissues, such as the skull or white matter, have an anisotropic conductivity. Many studies reported that the anisotropic conductivities have an influence on the calculated electrode potentials. However, few studies have assessed the influence of anisotropic conductivities on the dipole estimations. In this study, we want to determine the dipole estimation errors due to not taking into account the anisotropic conductivities of the skull and/or brain tissues. Therefore, head models are constructed with the same geometry, but with an anisotropically conducting skull and/or brain tissue compartment. These head models are used in simulation studies where the dipole location and orientation error is calculated due to neglecting anisotropic conductivities of the skull and brain tissue. Results show that not taking into account the anisotropic conductivities of the skull yields a dipole location error between 2 and 25 mm, with an average of 10 mm. When the anisotropic conductivities of the brain tissues are neglected, the dipole location error ranges between 0 and 5 mm. In this case, the average dipole location error was 2.3 mm. In all simulations, the dipole orientation error was smaller than 10 deg. We can conclude that the anisotropic conductivities of the skull have to be incorporated to improve the accuracy of EEG source analysis. The results of the simulation, as presented here, also suggest that incorporation of the anisotropic conductivities of brain tissues is not necessary. However, more studies are needed to confirm these suggestions.
Giuliani, Manuel; Mirnig, Nicole; Stollnberger, Gerald; Stadler, Susanne; Buchner, Roland; Tscheligi, Manfred
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 that there are two types of error situations: social norm violations and technical failures. Social norm violations are situations in which the robot does not adhere to the underlying social script of the interaction. Technical failures are caused by technical shortcomings of the robot. The results of the video analysis show that the study participants use many head movements and very few gestures, but they often smile, when in an error situation with the robot. Another result is that the participants sometimes stop moving at the beginning of error situations. We also found that the participants talked more in the case of social norm violations and less during technical failures. Finally, the participants use fewer non-verbal social signals (for example smiling, nodding, and head shaking), when they are interacting with the robot alone and no experimenter or other human is present. The results suggest that participants do not see the robot as a social interaction partner with comparable communication skills. Our findings have implications for builders and evaluators of human–robot interaction systems. The builders need to consider including modules for recognition and classification of head movements to the robot input channels. The evaluators need to make sure that the presence of an experimenter does not skew the results of their user studies. PMID:26217266
Giuliani, Manuel; Mirnig, Nicole; Stollnberger, Gerald; Stadler, Susanne; Buchner, Roland; Tscheligi, Manfred
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 that there are two types of error situations: social norm violations and technical failures. Social norm violations are situations in which the robot does not adhere to the underlying social script of the interaction. Technical failures are caused by technical shortcomings of the robot. The results of the video analysis show that the study participants use many head movements and very few gestures, but they often smile, when in an error situation with the robot. Another result is that the participants sometimes stop moving at the beginning of error situations. We also found that the participants talked more in the case of social norm violations and less during technical failures. Finally, the participants use fewer non-verbal social signals (for example smiling, nodding, and head shaking), when they are interacting with the robot alone and no experimenter or other human is present. The results suggest that participants do not see the robot as a social interaction partner with comparable communication skills. Our findings have implications for builders and evaluators of human-robot interaction systems. The builders need to consider including modules for recognition and classification of head movements to the robot input channels. The evaluators need to make sure that the presence of an experimenter does not skew the results of their user studies.
International Nuclear Information System (INIS)
Jang, Inseok; Kim, Ar Ryum; Jung, Wondea; Seong, Poong Hyun
2016-01-01
Highlights: • The operation environment of MCRs in NPPs has changed by adopting new HSIs. • The operation action in NPP Advanced MCRs is performed by soft control. • New HRA framework should be considered in the HRA for advanced MCRs. • HRA framework for evaluation of soft control execution human error is suggested. • Suggested method will be helpful to analyze human reliability in advance MCRs. - Abstract: Since the Three Mile Island (TMI)-2 accident, human error has been recognized as one of the main causes of Nuclear Power Plant (NPP) accidents, and numerous studies related to Human Reliability Analysis (HRA) have been carried out. Most of these methods were developed considering the conventional type of Main Control Rooms (MCRs). However, the operating environment of MCRs in NPPs has changed with the adoption of new Human-System Interfaces (HSIs) that are based on computer-based technologies. The MCRs that include these digital 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 operating actions in NPP advanced MCRs are performed by soft control. Due to the differences in interfaces between soft control and hardwired conventional type control, different Human Error Probabilities (HEPs) and a new HRA framework should be considered in the HRA for advanced MCRs. To this end, a new framework of a HRA method for evaluating soft control execution human error is suggested by performing a soft control task analysis and the literature regarding widely accepted human error taxonomies is reviewed. Moreover, since most current HRA databases deal with operation in conventional MCRs and are not explicitly designed to deal with digital HSIs, empirical analysis of human error and error recovery considering soft controls under an advanced MCR mockup are carried out to collect human error data, which is
International Nuclear Information System (INIS)
Jung, Won Dea; Kim, Jae Whan; Ha, Jae Joo; Yoon, Wan C.
1999-01-01
This study was performed to comparatively evaluate selected Human Reliability Analysis (HRA) methods which mainly focus on cognitive error analysis, and to derive the requirement of a new human error analysis (HEA) framework for Accident Management (AM) in nuclear power plants(NPPs). In order to achieve this goal, we carried out a case study of human error analysis on an AM task in NPPs. In the study we evaluated three cognitive HEA methods, HRMS, CREAM and PHECA, which were selected through the review of the currently available seven cognitive HEA methods. The task of reactor cavity flooding was chosen for the application study as one of typical tasks of AM in NPPs. From the study, we derived seven requirement items for a new HEA method of AM in NPPs. We could also evaluate the applicability of three cognitive HEA methods to AM tasks. CREAM is considered to be more appropriate than others for the analysis of AM tasks. But, PHECA is regarded less appropriate for the predictive HEA technique as well as for the analysis of AM tasks. In addition to these, the advantages and disadvantages of each method are described. (author)
Analysis of quantum error-correcting codes: Symplectic lattice codes and toric codes
Harrington, James William
Quantum information theory is concerned with identifying how quantum mechanical resources (such as entangled quantum states) can be utilized for a number of information processing tasks, including data storage, computation, communication, and cryptography. Efficient quantum algorithms and protocols have been developed for performing some tasks (e.g. , factoring large numbers, securely communicating over a public channel, and simulating quantum mechanical systems) that appear to be very difficult with just classical resources. In addition to identifying the separation between classical and quantum computational power, much of the theoretical focus in this field over the last decade has been concerned with finding novel ways of encoding quantum information that are robust against errors, which is an important step toward building practical quantum information processing devices. In this thesis I present some results on the quantum error-correcting properties of oscillator codes (also described as symplectic lattice codes) and toric codes. Any harmonic oscillator system (such as a mode of light) can be encoded with quantum information via symplectic lattice codes that are robust against shifts in the system's continuous quantum variables. I show the existence of lattice codes whose achievable rates match the one-shot coherent information over the Gaussian quantum channel. Also, I construct a family of symplectic self-dual lattices and search for optimal encodings of quantum information distributed between several oscillators. Toric codes provide encodings of quantum information into two-dimensional spin lattices that are robust against local clusters of errors and which require only local quantum operations for error correction. Numerical simulations of this system under various error models provide a calculation of the accuracy threshold for quantum memory using toric codes, which can be related to phase transitions in certain condensed matter models. I also present
Self-test web-based pure-tone audiometry: validity evaluation and measurement error analysis.
Masalski, Marcin; Kręcicki, Tomasz
2013-04-12
Potential methods of application of self-administered Web-based pure-tone audiometry conducted at home on a PC with a sound card and ordinary headphones depend on the value of measurement error in such tests. The aim of this research was to determine the measurement error of the hearing threshold determined in the way described above and to identify and analyze factors influencing its value. The evaluation of the hearing threshold was made in three series: (1) tests on a clinical audiometer, (2) self-tests done on a specially calibrated computer under the supervision of an audiologist, and (3) self-tests conducted at home. The research was carried out on the group of 51 participants selected from patients of an audiology outpatient clinic. From the group of 51 patients examined in the first two series, the third series was self-administered at home by 37 subjects (73%). The average difference between the value of the hearing threshold determined in series 1 and in series 2 was -1.54dB with standard deviation of 7.88dB and a Pearson correlation coefficient of .90. Between the first and third series, these values were -1.35dB±10.66dB and .84, respectively. In series 3, the standard deviation was most influenced by the error connected with the procedure of hearing threshold identification (6.64dB), calibration error (6.19dB), and additionally at the frequency of 250Hz by frequency nonlinearity error (7.28dB). The obtained results confirm the possibility of applying Web-based pure-tone audiometry in screening tests. In the future, modifications of the method leading to the decrease in measurement error can broaden the scope of Web-based pure-tone audiometry application.
Energy Technology Data Exchange (ETDEWEB)
Josset-Gaudaire, S.; Lisbona, A.; Llagostera, C.; Delpon, G.; Chiavassa, S.; Brunet, G. [Service de physique medicale, ICO Rene-Gauducheau, Saint Herblain (France); Rousset, S.; Nerriere, E.; Leblanc, M. [Service de radiotherapie, ICO Rene-Gauducheau, Saint Herblain (France)
2011-10-15
Within the frame of a study of control imagery management in radiotherapy, the authors report the study of positioning errors associated with control imagery in order to give an overview of practice and to help the adjustment or definition of action levels for clinical practice. Twenty groups of patients have been defined by considering tumour locations (head, ENT, thorax, breast, abdomen, and pelvis), treatment positions, immobilization systems and imagery systems. Positioning errors have thus been analyzed for 340 patients. Aspects and practice to be improved are identified. Short communication
Performance Analysis for Bit Error Rate of DS- CDMA Sensor Network Systems with Source Coding
Directory of Open Access Journals (Sweden)
Haider M. AlSabbagh
2012-03-01
Full Text Available The minimum energy (ME coding combined with DS-CDMA wireless sensor network is analyzed in order to reduce energy consumed and multiple access interference (MAI with related to number of user(receiver. Also, the minimum energy coding which exploits redundant bits for saving power with utilizing RF link and On-Off-Keying modulation. The relations are presented and discussed for several levels of errors expected in the employed channel via amount of bit error rates and amount of the SNR for number of users (receivers.
Hoede, C.; Li, Z.
2001-01-01
In coding theory the problem of decoding focuses on error vectors. In the simplest situation code words are $(0,1)$-vectors, as are the received messages and the error vectors. Comparison of a received word with the code words yields a set of error vectors. In deciding on the original code word,
Analysis Of The Effect Of Fuel Enrichment Error On Neutronic Properties Of The RSG-GAS Core
International Nuclear Information System (INIS)
Saragih, Tukiran; Pinem, Surian
2002-01-01
The analysis of the fuel enrichment error effect on neutronic properties has been carried out. The fuel enrichment could be improperly done because of wrong fabrication. Therefore it is necessary to analyze the fuel enrichment error effect to determine how many percents the fuel enrichment maximum can be accepted in the core. The analysis was done by simulation method The RSG-GAS core was simulated with 5 standard fuels and 1 control element having wrong enrichment when inserted into the core. Fuel enrichment error was then simulated from 20%, 25% and 30% and the simulation was done using WIMSD/4 and Batan-2DIFF codes. The cross section of core material of the RSG-GAS was generated by WIMSD/4 code in 1-D, X-Y geometry and 10 energy neutron group. Two dimensions, diffusion calculation based on finite element method was done by using Batan-2DIFF code. Five fuel elements and one control element changed the enrichment was finally arranged as a new core of the RSG-Gas reactor. The neutronic properties can be seen from eigenvalues (k eff ) as well as from the kinetic properties based on moderator void reactivity coefficient. The calculated results showed that the error are still acceptable by k eff 1,097 even until 25% fuel enrichment but not more than 25,5%