Systematic Error Study for ALICE charged-jet v2 Measurement

Energy Technology Data Exchange (ETDEWEB)

Heinz, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-07-18

We study the treatment of systematic errors in the determination of v₂ for charged jets in √ sNN = 2:76 TeV Pb-Pb collisions by the ALICE Collaboration. Working with the reported values and errors for the 0-5% centrality data we evaluate the Χ² according to the formulas given for the statistical and systematic errors, where the latter are separated into correlated and shape contributions. We reproduce both the Χ² and p-values relative to a null (zero) result. We then re-cast the systematic errors into an equivalent co-variance matrix and obtain identical results, demonstrating that the two methods are equivalent.

A Corpus-based Study of EFL Learners’ Errors in IELTS Essay Writing

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Hoda Divsar

2017-03-01

Full Text Available The present study analyzed different types of errors in the EFL learners’ IELTS essays. In order to determine the major types of errors, a corpus of 70 IELTS examinees’ writings were collected, and their errors were extracted and categorized qualitatively. Errors were categorized based on a researcher-developed error-coding scheme into 13 aspects. Based on the descriptive statistical analyses, the frequency of each error type was calculated and the commonest errors committed by the EFL learners in IELTS essays were identified. The results indicated that the two most frequent errors that IELTS candidates committed were related to word choice and verb forms. Based on the research results, pedagogical implications highlight analyzing EFL learners’ writing errors as a useful basis for instructional purposes including creating pedagogical teaching materials that are in line with learners’ linguistic strengths and weaknesses.

Coherent error study in a retarding field energy analyzer

International Nuclear Information System (INIS)

Cui, Y.; Zou, Y.; Reiser, M.; Kishek, R.A.; Haber, I.; Bernal, S.; O'Shea, P.G.

2005-01-01

A novel cylindrical retarding electrostatic field energy analyzer for low-energy beams has been designed, simulated, and tested with electron beams of several keV, in which space charge effects play an important role. A cylindrical focusing electrode is used to overcome the beam expansion inside the device due to space-charge forces, beam emittance, etc. In this paper, we present the coherent error analysis for this energy analyzer with beam envelope equation including space charge and emittance effects. The study shows that this energy analyzer can achieve very high resolution (with relative error of around 10 -5 ) if taking away the coherent errors by using proper focusing voltages. The theoretical analysis is compared with experimental results

Dissociable genetic contributions to error processing: a multimodal neuroimaging study.

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Yigal Agam

Full Text Available Neuroimaging studies reliably identify two markers of error commission: the error-related negativity (ERN, an event-related potential, and functional MRI activation of the dorsal anterior cingulate cortex (dACC. While theorized to reflect the same neural process, recent evidence suggests that the ERN arises from the posterior cingulate cortex not the dACC. Here, we tested the hypothesis that these two error markers also have different genetic mediation.We measured both error markers in a sample of 92 comprised of healthy individuals and those with diagnoses of schizophrenia, obsessive-compulsive disorder or autism spectrum disorder. Participants performed the same task during functional MRI and simultaneously acquired magnetoencephalography and electroencephalography. We examined the mediation of the error markers by two single nucleotide polymorphisms: dopamine D4 receptor (DRD4 C-521T (rs1800955, which has been associated with the ERN and methylenetetrahydrofolate reductase (MTHFR C677T (rs1801133, which has been associated with error-related dACC activation. We then compared the effects of each polymorphism on the two error markers modeled as a bivariate response.We replicated our previous report of a posterior cingulate source of the ERN in healthy participants in the schizophrenia and obsessive-compulsive disorder groups. The effect of genotype on error markers did not differ significantly by diagnostic group. DRD4 C-521T allele load had a significant linear effect on ERN amplitude, but not on dACC activation, and this difference was significant. MTHFR C677T allele load had a significant linear effect on dACC activation but not ERN amplitude, but the difference in effects on the two error markers was not significant.DRD4 C-521T, but not MTHFR C677T, had a significant differential effect on two canonical error markers. Together with the anatomical dissociation between the ERN and error-related dACC activation, these findings suggest that

Error or "act of God"? A study of patients' and operating room team members' perceptions of error definition, reporting, and disclosure.

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Espin, Sherry; Levinson, Wendy; Regehr, Glenn; Baker, G Ross; Lingard, Lorelei

2006-01-01

Calls abound for a culture change in health care to improve patient safety. However, effective change cannot proceed without a clear understanding of perceptions and beliefs about error. In this study, we describe and compare operative team members' and patients' perceptions of error, reporting of error, and disclosure of error. Thirty-nine interviews of team members (9 surgeons, 9 nurses, 10 anesthesiologists) and patients (11) were conducted at 2 teaching hospitals using 4 scenarios as prompts. Transcribed responses to open questions were analyzed by 2 researchers for recurrent themes using the grounded-theory method. Yes/no answers were compared across groups using chi-square analyses. Team members and patients agreed on what constitutes an error. Deviation from standards and negative outcome were emphasized as definitive features. Patients and nurse professionals differed significantly in their perception of whether errors should be reported. Nurses were willing to report only events within their disciplinary scope of practice. Although most patients strongly advocated full disclosure of errors (what happened and how), team members preferred to disclose only what happened. When patients did support partial disclosure, their rationales varied from that of team members. Both operative teams and patients define error in terms of breaking the rules and the concept of "no harm no foul." These concepts pose challenges for treating errors as system failures. A strong culture of individualism pervades nurses' perception of error reporting, suggesting that interventions are needed to foster collective responsibility and a constructive approach to error identification.

Error floor behavior study of LDPC codes for concatenated codes design

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Chen, Weigang; Yin, Liuguo; Lu, Jianhua

2007-11-01

Error floor behavior of low-density parity-check (LDPC) codes using quantized decoding algorithms is statistically studied with experimental results on a hardware evaluation platform. The results present the distribution of the residual errors after decoding failure and reveal that the number of residual error bits in a codeword is usually very small using quantized sum-product (SP) algorithm. Therefore, LDPC code may serve as the inner code in a concatenated coding system with a high code rate outer code and thus an ultra low error floor can be achieved. This conclusion is also verified by the experimental results.

Proportion of medication error reporting and associated factors among nurses: a cross sectional study.

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Jember, Abebaw; Hailu, Mignote; Messele, Anteneh; Demeke, Tesfaye; Hassen, Mohammed

2018-01-01

A medication error (ME) is any preventable event that may cause or lead to inappropriate medication use or patient harm. Voluntary reporting has a principal role in appreciating the extent and impact of medication errors. Thus, exploration of the proportion of medication error reporting and associated factors among nurses is important to inform service providers and program implementers so as to improve the quality of the healthcare services. Institution based quantitative cross-sectional study was conducted among 397 nurses from March 6 to May 10, 2015. Stratified sampling followed by simple random sampling technique was used to select the study participants. The data were collected using structured self-administered questionnaire which was adopted from studies conducted in Australia and Jordan. A pilot study was carried out to validate the questionnaire before data collection for this study. Bivariate and multivariate logistic regression models were fitted to identify factors associated with the proportion of medication error reporting among nurses. An adjusted odds ratio with 95% confidence interval was computed to determine the level of significance. The proportion of medication error reporting among nurses was found to be 57.4%. Regression analysis showed that sex, marital status, having made a medication error and medication error experience were significantly associated with medication error reporting. The proportion of medication error reporting among nurses in this study was found to be higher than other studies.

Numerical study of the systematic error in Monte Carlo schemes for semiconductors

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Muscato, Orazio [Univ. degli Studi di Catania (Italy). Dipt. di Matematica e Informatica; Di Stefano, Vincenza [Univ. degli Studi di Messina (Italy). Dipt. di Matematica; Wagner, Wolfgang [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany)

2008-07-01

The paper studies the convergence behavior of Monte Carlo schemes for semiconductors. A detailed analysis of the systematic error with respect to numerical parameters is performed. Different sources of systematic error are pointed out and illustrated in a spatially one-dimensional test case. The error with respect to the number of simulation particles occurs during the calculation of the internal electric field. The time step error, which is related to the splitting of transport and electric field calculations, vanishes sufficiently fast. The error due to the approximation of the trajectories of particles depends on the ODE solver used in the algorithm. It is negligible compared to the other sources of time step error, when a second order Runge-Kutta solver is used. The error related to the approximate scattering mechanism is the most significant source of error with respect to the time step. (orig.)

Study of systematic errors in the luminosity measurement

International Nuclear Information System (INIS)

Arima, Tatsumi

1993-01-01

The experimental systematic error in the barrel region was estimated to be 0.44 %. This value is derived considering the systematic uncertainties from the dominant sources but does not include uncertainties which are being studied. In the end cap region, the study of shower behavior and clustering effect is under way in order to determine the angular resolution at the low angle edge of the Liquid Argon Calorimeter. We also expect that the systematic error in this region will be less than 1 %. The technical precision of theoretical uncertainty is better than 0.1 % comparing the Tobimatsu-Shimizu program and BABAMC modified by ALEPH. To estimate the physical uncertainty we will use the ALIBABA [9] which includes O(α 2 ) QED correction in leading-log approximation. (J.P.N.)

Study of systematic errors in the luminosity measurement

Energy Technology Data Exchange (ETDEWEB)

Arima, Tatsumi [Tsukuba Univ., Ibaraki (Japan). Inst. of Applied Physics

1993-04-01

The experimental systematic error in the barrel region was estimated to be 0.44 %. This value is derived considering the systematic uncertainties from the dominant sources but does not include uncertainties which are being studied. In the end cap region, the study of shower behavior and clustering effect is under way in order to determine the angular resolution at the low angle edge of the Liquid Argon Calorimeter. We also expect that the systematic error in this region will be less than 1 %. The technical precision of theoretical uncertainty is better than 0.1 % comparing the Tobimatsu-Shimizu program and BABAMC modified by ALEPH. To estimate the physical uncertainty we will use the ALIBABA [9] which includes O({alpha}{sup 2}) QED correction in leading-log approximation. (J.P.N.).

Operator errors

International Nuclear Information System (INIS)

Knuefer; Lindauer

1980-01-01

Besides that at spectacular events a combination of component failure and human error is often found. Especially the Rasmussen-Report and the German Risk Assessment Study show for pressurised water reactors that human error must not be underestimated. Although operator errors as a form of human error can never be eliminated entirely, they can be minimized and their effects kept within acceptable limits if a thorough training of personnel is combined with an adequate design of the plant against accidents. Contrary to the investigation of engineering errors, the investigation of human errors has so far been carried out with relatively small budgets. Intensified investigations in this field appear to be a worthwhile effort. (orig.)

A second study of the prediction of cognitive errors using the 'CREAM' technique

International Nuclear Information System (INIS)

Collier, Steve; Andresen, Gisle

2000-03-01

Some human errors, such as errors of commission and knowledge-based errors, are not adequately modelled in probabilistic safety assessments. Even qualitative methods for handling these sorts of errors are comparatively underdeveloped. The 'Cognitive Reliability and Error Analysis Method' (CREAM) was recently developed for prediction of cognitive error modes. It has not yet been comprehensively established how reliable, valid and generally useful it could be to researchers and practitioners. A previous study of CREAM at Halden was promising, showing a relationship between errors predicted in advance and those that actually occurred in simulated fault scenarios. The present study continues this work. CREAM was used to make predictions of cognitive error modes throughout two rather difficult fault scenarios. Predictions were made of the most likely cognitive error mode, were one to occur at all, at several points throughout the expected scenarios, based upon the scenario design and description. Each scenario was then run 15 times with different operators. Error modes occurring during simulations were later scored using the task description for the scenario, videotapes of operator actions, eye-track recording, operators' verbal protocols and an expert's concurrent commentary. The scoring team had no previous substantive knowledge of the experiment or the techniques used, so as to provide a more stringent test of the data and knowledge needed for scoring. The scored error modes were then compared with the CREAM predictions to assess the degree of agreement. Some cognitive error modes were predicted successfully, but the results were generally not so encouraging as the previous study. Several problems were found with both the CREAM technique and the data needed to complete the analysis. It was felt that further development was needed before this kind of analysis can be reliable and valid, either in a research setting or as a practitioner's tool in a safety assessment

Characteristics of pediatric chemotherapy medication errors in a national error reporting database.

Science.gov (United States)

Rinke, Michael L; Shore, Andrew D; Morlock, Laura; Hicks, Rodney W; Miller, Marlene R

2007-07-01

Little is known regarding chemotherapy medication errors in pediatrics despite studies suggesting high rates of overall pediatric medication errors. In this study, the authors examined patterns in pediatric chemotherapy errors. The authors queried the United States Pharmacopeia MEDMARX database, a national, voluntary, Internet-accessible error reporting system, for all error reports from 1999 through 2004 that involved chemotherapy medications and patients aged error reports, 85% reached the patient, and 15.6% required additional patient monitoring or therapeutic intervention. Forty-eight percent of errors originated in the administering phase of medication delivery, and 30% originated in the drug-dispensing phase. Of the 387 medications cited, 39.5% were antimetabolites, 14.0% were alkylating agents, 9.3% were anthracyclines, and 9.3% were topoisomerase inhibitors. The most commonly involved chemotherapeutic agents were methotrexate (15.3%), cytarabine (12.1%), and etoposide (8.3%). The most common error types were improper dose/quantity (22.9% of 327 cited error types), wrong time (22.6%), omission error (14.1%), and wrong administration technique/wrong route (12.2%). The most common error causes were performance deficit (41.3% of 547 cited error causes), equipment and medication delivery devices (12.4%), communication (8.8%), knowledge deficit (6.8%), and written order errors (5.5%). Four of the 5 most serious errors occurred at community hospitals. Pediatric chemotherapy errors often reached the patient, potentially were harmful, and differed in quality between outpatient and inpatient areas. This study indicated which chemotherapeutic agents most often were involved in errors and that administering errors were common. Investigation is needed regarding targeted medication administration safeguards for these high-risk medications. Copyright (c) 2007 American Cancer Society.

Errors in translation made by English major students: A study on types and causes

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Pattanapong Wongranu

2017-05-01

Full Text Available Many Thai English major students have problems when they translate Thai texts into English, as numerous errors can be found. Therefore, a study of translation errors is needed to find solutions to these problems. The objectives of this research were: 1 to examine types of translation errors in translation from Thai into English, 2 to determine the types of translation errors that are most common, and 3 to find possible explanations for the causes of errors. The results of this study will be used to improve translation teaching and the course “Translation from Thai into English”. The participants were 26 third-year, English major students at Kasetsart University. The data were collected from the students' exercises and examinations. Interviews and stimulated recall were also used to determine translation problems and causes of errors. The data were analyzed by considering the frequency and percentage, and by content analysis. The results shows that the most frequent translation errors were syntactic errors (65%, followed by semantic errors (26.5% and miscellaneous errors (8.5%, respectively. The causes of errors found in this study included translation procedures, carelessness, low self-confidence, and anxiety. It is recommended that more class time be spent to address the problematic points. In addition, more authentic translation and group work should be implemented to increase self-confidence and decrease anxiety.

Decreasing scoring errors on Wechsler Scale Vocabulary, Comprehension, and Similarities subtests: a preliminary study.

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Linger, Michele L; Ray, Glen E; Zachar, Peter; Underhill, Andrea T; LoBello, Steven G

2007-10-01

Studies of graduate students learning to administer the Wechsler scales have generally shown that training is not associated with the development of scoring proficiency. Many studies report on the reduction of aggregated administration and scoring errors, a strategy that does not highlight the reduction of errors on subtests identified as most prone to error. This study evaluated the development of scoring proficiency specifically on the Wechsler (WISC-IV and WAIS-III) Vocabulary, Comprehension, and Similarities subtests during training by comparing a set of 'early test administrations' to 'later test administrations.' Twelve graduate students enrolled in an intelligence-testing course participated in the study. Scoring errors (e.g., incorrect point assignment) were evaluated on the students' actual practice administration test protocols. Errors on all three subtests declined significantly when scoring errors on 'early' sets of Wechsler scales were compared to those made on 'later' sets. However, correcting these subtest scoring errors did not cause significant changes in subtest scaled scores. Implications for clinical instruction and future research are discussed.

Error-related anterior cingulate cortex activity and the prediction of conscious error awareness

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Catherine eOrr

2012-06-01

Full Text Available Research examining the neural mechanisms associated with error awareness has consistently identified dorsal anterior cingulate activity (ACC as necessary but not predictive of conscious error detection. Two recent studies (Steinhauser and Yeung, 2010; Wessel et al. 2011 have found a contrary pattern of greater dorsal ACC activity (in the form of the error-related negativity during detected errors, but suggested that the greater activity may instead reflect task influences (e.g., response conflict, error probability and or individual variability (e.g., statistical power. We re-analyzed fMRI BOLD data from 56 healthy participants who had previously been administered the Error Awareness Task, a motor Go/No-go response inhibition task in which subjects make errors of commission of which they are aware (Aware errors, or unaware (Unaware errors. Consistent with previous data, the activity in a number of cortical regions was predictive of error awareness, including bilateral inferior parietal and insula cortices, however in contrast to previous studies, including our own smaller sample studies using the same task, error-related dorsal ACC activity was significantly greater during aware errors when compared to unaware errors. While the significantly faster RT for aware errors (compared to unaware was consistent with the hypothesis of higher response conflict increasing ACC activity, we could find no relationship between dorsal ACC activity and the error RT difference. The data suggests that individual variability in error awareness is associated with error-related dorsal ACC activity, and therefore this region may be important to conscious error detection, but it remains unclear what task and individual factors influence error awareness.

Error-related brain activity and error awareness in an error classification paradigm.

Science.gov (United States)

Di Gregorio, Francesco; Steinhauser, Marco; Maier, Martin E

2016-10-01

Error-related brain activity has been linked to error detection enabling adaptive behavioral adjustments. However, it is still unclear which role error awareness plays in this process. Here, we show that the error-related negativity (Ne/ERN), an event-related potential reflecting early error monitoring, is dissociable from the degree of error awareness. Participants responded to a target while ignoring two different incongruent distractors. After responding, they indicated whether they had committed an error, and if so, whether they had responded to one or to the other distractor. This error classification paradigm allowed distinguishing partially aware errors, (i.e., errors that were noticed but misclassified) and fully aware errors (i.e., errors that were correctly classified). The Ne/ERN was larger for partially aware errors than for fully aware errors. Whereas this speaks against the idea that the Ne/ERN foreshadows the degree of error awareness, it confirms the prediction of a computational model, which relates the Ne/ERN to post-response conflict. This model predicts that stronger distractor processing - a prerequisite of error classification in our paradigm - leads to lower post-response conflict and thus a smaller Ne/ERN. This implies that the relationship between Ne/ERN and error awareness depends on how error awareness is related to response conflict in a specific task. Our results further indicate that the Ne/ERN but not the degree of error awareness determines adaptive performance adjustments. Taken together, we conclude that the Ne/ERN is dissociable from error awareness and foreshadows adaptive performance adjustments. Our results suggest that the relationship between the Ne/ERN and error awareness is correlative and mediated by response conflict. Copyright © 2016 Elsevier Inc. All rights reserved.

Calculation of track and vertex errors for detector design studies

International Nuclear Information System (INIS)

Harr, R.

1995-01-01

The Kalman Filter technique has come into wide use for charged track reconstruction in high-energy physics experiments. It is also well suited for detector design studies, allowing for the efficient estimation of optimal track covariance matrices without the need of a hit level Monte Carlo simulation. Although much has been published about the Kalman filter equations, there is a lack of previous literature explaining how to implement the equations. In this paper, the operators necessary to implement the Kalman filter equations for two common detector configurations are worked out: a central detector in a uniform solenoidal magnetic field, and a fixed-target detector with no magnetic field in the region of the interactions. With the track covariance matrices in hand, vertex and invariant mass errors are readily calculable. These quantities are particularly interesting for evaluating experiments designed to study weakly decaying particles which give rise to displaced vertices. The optimal vertex errors are obtained via a constrained vertex fit. Solutions are presented to the constrained vertex problem with and without kinematic constraints. Invariant mass errors are obtained via propagation of errors; the use of vertex constrained track parameters is discussed. Many of the derivations are new or previously unpublished

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

How Do Simulated Error Experiences Impact Attitudes Related to Error Prevention?

Science.gov (United States)

Breitkreuz, Karen R; Dougal, Renae L; Wright, Melanie C

2016-10-01

The objective of this project was to determine whether simulated exposure to error situations changes attitudes in a way that may have a positive impact on error prevention behaviors. Using a stratified quasi-randomized experiment design, we compared risk perception attitudes of a control group of nursing students who received standard error education (reviewed medication error content and watched movies about error experiences) to an experimental group of students who reviewed medication error content and participated in simulated error experiences. Dependent measures included perceived memorability of the educational experience, perceived frequency of errors, and perceived caution with respect to preventing errors. Experienced nursing students perceived the simulated error experiences to be more memorable than movies. Less experienced students perceived both simulated error experiences and movies to be highly memorable. After the intervention, compared with movie participants, simulation participants believed errors occurred more frequently. Both types of education increased the participants' intentions to be more cautious and reported caution remained higher than baseline for medication errors 6 months after the intervention. This study provides limited evidence of an advantage of simulation over watching movies describing actual errors with respect to manipulating attitudes related to error prevention. Both interventions resulted in long-term impacts on perceived caution in medication administration. Simulated error experiences made participants more aware of how easily errors can occur, and the movie education made participants more aware of the devastating consequences of errors.

Prediction-error variance in Bayesian model updating: a comparative study

Science.gov (United States)

Asadollahi, Parisa; Li, Jian; Huang, Yong

2017-04-01

In Bayesian model updating, the likelihood function is commonly formulated by stochastic embedding in which the maximum information entropy probability model of prediction error variances plays an important role and it is Gaussian distribution subject to the first two moments as constraints. The selection of prediction error variances can be formulated as a model class selection problem, which automatically involves a trade-off between the average data-fit of the model class and the information it extracts from the data. Therefore, it is critical for the robustness in the updating of the structural model especially in the presence of modeling errors. To date, three ways of considering prediction error variances have been seem in the literature: 1) setting constant values empirically, 2) estimating them based on the goodness-of-fit of the measured data, and 3) updating them as uncertain parameters by applying Bayes' Theorem at the model class level. In this paper, the effect of different strategies to deal with the prediction error variances on the model updating performance is investigated explicitly. A six-story shear building model with six uncertain stiffness parameters is employed as an illustrative example. Transitional Markov Chain Monte Carlo is used to draw samples of the posterior probability density function of the structure model parameters as well as the uncertain prediction variances. The different levels of modeling uncertainty and complexity are modeled through three FE models, including a true model, a model with more complexity, and a model with modeling error. Bayesian updating is performed for the three FE models considering the three aforementioned treatments of the prediction error variances. The effect of number of measurements on the model updating performance is also examined in the study. The results are compared based on model class assessment and indicate that updating the prediction error variances as uncertain parameters at the model

Uncorrected refractive errors.

Science.gov (United States)

Naidoo, Kovin S; Jaggernath, Jyoti

2012-01-01

Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC), were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR) Development, Service Development and Social Entrepreneurship.

Uncorrected refractive errors

Directory of Open Access Journals (Sweden)

Kovin S Naidoo

2012-01-01

Full Text Available Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC, were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR Development, Service Development and Social Entrepreneurship.

Learning from Errors: An Exploratory Study Among Dutch Auditors

NARCIS (Netherlands)

Gold, A.H.; van Mourik, O.; Van Dyck, Cathy; Wallage, P.

2017-01-01

Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

Learning from Errors: An Exploratory Study Among Dutch Auditors

NARCIS (Netherlands)

Gold, A.H.; Van Dyck, Cathy; Wallage, P.

Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

Learning from Errors: An Exploratory Study Among Dutch Auditors

NARCIS (Netherlands)

Gold, A.H.; Van Dyck, Cathy; Wallage, P.

2016-01-01

Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

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.

Empirical study of the GARCH model with rational errors

International Nuclear Information System (INIS)

Chen, Ting Ting; Takaishi, Tetsuya

2013-01-01

We use the GARCH model with a fat-tailed error distribution described by a rational function and apply it to stock price data on the Tokyo Stock Exchange. To determine the model parameters we perform Bayesian inference to the model. Bayesian inference is implemented by the Metropolis-Hastings algorithm with an adaptive multi-dimensional Student's t-proposal density. In order to compare our model with the GARCH model with the standard normal errors, we calculate the information criteria AIC and DIC, and find that both criteria favor the GARCH model with a rational error distribution. We also calculate the accuracy of the volatility by using the realized volatility and find that a good accuracy is obtained for the GARCH model with a rational error distribution. Thus we conclude that the GARCH model with a rational error distribution is superior to the GARCH model with the normal errors and it can be used as an alternative GARCH model to those with other fat-tailed distributions

Predictive error detection in pianists: A combined ERP and motion capture study

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Clemens eMaidhof

2013-09-01

Full Text Available Performing a piece of music involves the interplay of several cognitive and motor processes and requires extensive training to achieve a high skill level. However, even professional musicians commit errors occasionally. Previous event-related potential (ERP studies have investigated the neurophysiological correlates of pitch errors during piano performance, and reported pre-error negativity already occurring approximately 70-100 ms before the error had been committed and audible. It was assumed that this pre-error negativity reflects predictive control processes that compare predicted consequences with actual consequences of one’s own actions. However, in previous investigations, correct and incorrect pitch events were confounded by their different tempi. In addition, no data about the underlying movements were available. In the present study, we exploratively recorded the ERPs and 3D movement data of pianists’ fingers simultaneously while they performed fingering exercises from memory. Results showed a pre-error negativity for incorrect keystrokes when both correct and incorrect keystrokes were performed with comparable tempi. Interestingly, even correct notes immediately preceding erroneous keystrokes elicited a very similar negativity. In addition, we explored the possibility of computing ERPs time-locked to a kinematic landmark in the finger motion trajectories defined by when a finger makes initial contact with the key surface, that is, at the onset of tactile feedback. Results suggest that incorrect notes elicited a small difference after the onset of tactile feedback, whereas correct notes preceding incorrect ones elicited negativity before the onset of tactile feedback. The results tentatively suggest that tactile feedback plays an important role in error-monitoring during piano performance, because the comparison between predicted and actual sensory (tactile feedback may provide the information necessary for the detection of an

Action errors, error management, and learning in organizations.

Science.gov (United States)

Frese, Michael; Keith, Nina

2015-01-03

Every organization is confronted with errors. Most errors are corrected easily, but some may lead to negative consequences. Organizations often focus on error prevention as a single strategy for dealing with errors. Our review suggests that error prevention needs to be supplemented by error management--an approach directed at effectively dealing with errors after they have occurred, with the goal of minimizing negative and maximizing positive error consequences (examples of the latter are learning and innovations). After defining errors and related concepts, we review research on error-related processes affected by error management (error detection, damage control). Empirical evidence on positive effects of error management in individuals and organizations is then discussed, along with emotional, motivational, cognitive, and behavioral pathways of these effects. Learning from errors is central, but like other positive consequences, learning occurs under certain circumstances--one being the development of a mind-set of acceptance of human error.

Modeling coherent errors in quantum error correction

Science.gov (United States)

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.

Errors in causal inference: an organizational schema for systematic error and random error.

Science.gov (United States)

Suzuki, Etsuji; Tsuda, Toshihide; Mitsuhashi, Toshiharu; Mansournia, Mohammad Ali; Yamamoto, Eiji

2016-11-01

To provide an organizational schema for systematic error and random error in estimating causal measures, aimed at clarifying the concept of errors from the perspective of causal inference. We propose to divide systematic error into structural error and analytic error. With regard to random error, our schema shows its four major sources: nondeterministic counterfactuals, sampling variability, a mechanism that generates exposure events and measurement variability. Structural error is defined from the perspective of counterfactual reasoning and divided into nonexchangeability bias (which comprises confounding bias and selection bias) and measurement bias. Directed acyclic graphs are useful to illustrate this kind of error. Nonexchangeability bias implies a lack of "exchangeability" between the selected exposed and unexposed groups. A lack of exchangeability is not a primary concern of measurement bias, justifying its separation from confounding bias and selection bias. Many forms of analytic errors result from the small-sample properties of the estimator used and vanish asymptotically. Analytic error also results from wrong (misspecified) statistical models and inappropriate statistical methods. Our organizational schema is helpful for understanding the relationship between systematic error and random error from a previously less investigated aspect, enabling us to better understand the relationship between accuracy, validity, and precision. Copyright © 2016 Elsevier Inc. All rights reserved.

Errors and discrepancies in the administration of intravenous infusions: a mixed methods multihospital observational study

OpenAIRE

Lyons, I.; Furniss, D.; Blandford, A.; Chumbley, G.; Iacovides, I.; Wei, L.; Cox, A.; Mayer, A.; Vos, J.; Galal-Edeen, G. H.; Schnock, K. O.; Dykes, P. C.; Bates, D. W.; Franklin, B. D.

2018-01-01

INTRODUCTION: Intravenous medication administration has traditionally been regarded as error prone, with high potential for harm. A recent US multisite study revealed few potentially harmful errors despite a high overall error rate. However, there is limited evidence about infusion practices in England and how they relate to prevalence and types of error. OBJECTIVES: To determine the prevalence, types and severity of errors and discrepancies in infusion administration in English hospitals, an...

Quantification and handling of sampling errors in instrumental measurements: a case study

DEFF Research Database (Denmark)

Andersen, Charlotte Møller; Bro, R.

2004-01-01

in certain situations, the effect of systematic errors is also considerable. The relevant errors contributing to the prediction error are: error in instrumental measurements (x-error), error in reference measurements (y-error), error in the estimated calibration model (regression coefficient error) and model...

Awareness of Diagnostic Error among Japanese Residents: a Nationwide Study.

Science.gov (United States)

Nishizaki, Yuji; Shinozaki, Tomohiro; Kinoshita, Kensuke; Shimizu, Taro; Tokuda, Yasuharu

2018-04-01

Residents' understanding of diagnostic error may differ between countries. We sought to explore the relationship between diagnostic error knowledge and self-study, clinical knowledge, and experience. Our nationwide study involved postgraduate year 1 and 2 (PGY-1 and -2) Japanese residents. The Diagnostic Error Knowledge Assessment Test (D-KAT) and General Medicine In-Training Examination (GM-ITE) were administered at the end of the 2014 academic year. D-KAT scores were compared with the benchmark scores of US residents. Associations between D-KAT score and gender, PGY, emergency department (ED) rotations per month, mean number of inpatients handled at any given time, and mean daily minutes of self-study were also analyzed, both with and without adjusting for GM-ITE scores. Student's t test was used for comparisons with linear mixed models and structural equation models (SEM) to explore associations with D-KAT or GM-ITE scores. The mean D-KAT score among Japanese PGY-2 residents was significantly lower than that of their US PGY-2 counterparts (6.2 vs. 8.3, p ITE scores correlated with ED rotations (≥6 rotations: 2.14; 0.16-4.13; p = 0.03), inpatient caseloads (5-9 patients: 1.79; 0.82-2.76; p ITE scores (ß = 0.37, 95% CI: 0.34-0.41) and indirectly associated with ED rotations (ß = 0.06, 95% CI: 0.02-0.10), inpatient caseload (ß = 0.04, 95% CI: 0.003-0.08), and average daily minutes of study (ß = 0.13, 95% CI: 0.09-0.17). Knowledge regarding diagnostic error among Japanese residents was poor compared with that among US residents. D-KAT scores correlated strongly with GM-ITE scores, and the latter scores were positively associated with a greater number of ED rotations, larger caseload (though only up to 15 patients), and more time spent studying.

Correcting the Standard Errors of 2-Stage Residual Inclusion Estimators for Mendelian Randomization Studies.

Science.gov (United States)

Palmer, Tom M; Holmes, Michael V; Keating, Brendan J; Sheehan, Nuala A

2017-11-01

Mendelian randomization studies use genotypes as instrumental variables to test for and estimate the causal effects of modifiable risk factors on outcomes. Two-stage residual inclusion (TSRI) estimators have been used when researchers are willing to make parametric assumptions. However, researchers are currently reporting uncorrected or heteroscedasticity-robust standard errors for these estimates. We compared several different forms of the standard error for linear and logistic TSRI estimates in simulations and in real-data examples. Among others, we consider standard errors modified from the approach of Newey (1987), Terza (2016), and bootstrapping. In our simulations Newey, Terza, bootstrap, and corrected 2-stage least squares (in the linear case) standard errors gave the best results in terms of coverage and type I error. In the real-data examples, the Newey standard errors were 0.5% and 2% larger than the unadjusted standard errors for the linear and logistic TSRI estimators, respectively. We show that TSRI estimators with modified standard errors have correct type I error under the null. Researchers should report TSRI estimates with modified standard errors instead of reporting unadjusted or heteroscedasticity-robust standard errors. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

Medication Errors in an Internal Intensive Care Unit of a Large Teaching Hospital: A Direct Observation Study

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Saadat Delfani

2012-06-01

Full Text Available Medication errors account for about 78% of serious medical errors in intensive care unit (ICU. So far no study has been performed in Iran to evaluate all type of possible medication errors in ICU. Therefore the objective of this study was to reveal the frequency, type and consequences of all type of errors in an ICU of a large teaching hospital. The prospective observational study was conducted in an 11 bed internal ICU of a university hospital in Shiraz. In each shift all processes that were performed on one selected patient was observed and recorded by a trained pharmacist. Observer would intervene only if medication error would cause substantial harm. The data was evaluated and then were entered in a form that was designed for this purpose. The study continued for 38 shifts. During this period, a total of 442 errors per 5785 opportunities for errors (7.6% occurred. Of those, there were 9.8% administration errors, 6.8% prescribing errors, 3.3% transcription errors and, 2.3% dispensing errors. Totally 45 interventions were made, 40% of interventions result in the correction of errors. The most common causes of errors were observed to be: rule violations, slip and memory lapses and lack of drug knowledge. According to our results, the rate of errors is alarming and requires implementation of a serious solution. Since our system lacks a well-organize detection and reporting mechanism, there is no means for preventing errors in the first place. Hence, as the first step we must implement a system where errors are routinely detected and reported.

Assessment of the uncertainty associated with systematic errors in digital instruments: an experimental study on offset errors

International Nuclear Information System (INIS)

Attivissimo, F; Giaquinto, N; Savino, M; Cataldo, A

2012-01-01

This paper deals with the assessment of the uncertainty due to systematic errors, particularly in A/D conversion-based instruments. The problem of defining and assessing systematic errors is briefly discussed, and the conceptual scheme of gauge repeatability and reproducibility is adopted. A practical example regarding the evaluation of the uncertainty caused by the systematic offset error is presented. The experimental results, obtained under various ambient conditions, show that modelling the variability of systematic errors is more problematic than suggested by the ISO 5725 norm. Additionally, the paper demonstrates the substantial difference between the type B uncertainty evaluation, obtained via the maximum entropy principle applied to manufacturer's specifications, and the type A (experimental) uncertainty evaluation, which reflects actually observable reality. Although it is reasonable to assume a uniform distribution of the offset error, experiments demonstrate that the distribution is not centred and that a correction must be applied. In such a context, this work motivates a more pragmatic and experimental approach to uncertainty, with respect to the directions of supplement 1 of GUM. (paper)

The causes of prescribing errors in English general practices: a qualitative study.

Science.gov (United States)

Slight, Sarah P; Howard, Rachel; Ghaleb, Maisoon; Barber, Nick; Franklin, Bryony Dean; Avery, Anthony J

2013-10-01

Few detailed studies exist of the underlying causes of prescribing errors in the UK. To examine the causes of prescribing and monitoring errors in general practice and provide recommendations for how they may be overcome. Qualitative interview and focus group study with purposive sampling of English general practices. General practice staff from 15 general practices across three PCTs in England participated in a combination of semi-structured interviews (n = 34) and six focus groups (n = 46). Thematic analysis informed by Reason's Accident Causation Model was used. Seven categories of high-level error-producing conditions were identified: the prescriber, the patient, the team, the working environment, the task, the computer system, and the primary-secondary care interface. These were broken down to reveal various error-producing conditions: the prescriber's therapeutic training, drug knowledge and experience, knowledge of the patient, perception of risk, and their physical and emotional health; the patient's characteristics and the complexity of the individual clinical case; the importance of feeling comfortable within the practice team was highlighted, as well as the safety implications of GPs signing prescriptions generated by nurses when they had not seen the patient for themselves; the working environment with its extensive workload, time pressures, and interruptions; and computer-related issues associated with mis-selecting drugs from electronic pick-lists and overriding alerts were all highlighted as possible causes of prescribing errors and were often interconnected. Complex underlying causes of prescribing and monitoring errors in general practices were highlighted, several of which are amenable to intervention.

Error Detection and Error Classification: Failure Awareness in Data Transfer Scheduling

Energy Technology Data Exchange (ETDEWEB)

Louisiana State University; Balman, Mehmet; Kosar, Tevfik

2010-10-27

Data transfer in distributed environment is prone to frequent failures resulting from back-end system level problems, like connectivity failure which is technically untraceable by users. Error messages are not logged efficiently, and sometimes are not relevant/useful from users point-of-view. Our study explores the possibility of an efficient error detection and reporting system for such environments. Prior knowledge about the environment and awareness of the actual reason behind a failure would enable higher level planners to make better and accurate decisions. It is necessary to have well defined error detection and error reporting methods to increase the usability and serviceability of existing data transfer protocols and data management systems. We investigate the applicability of early error detection and error classification techniques and propose an error reporting framework and a failure-aware data transfer life cycle to improve arrangement of data transfer operations and to enhance decision making of data transfer schedulers.

Medication errors with the use of allopurinol and colchicine: a retrospective study of a national, anonymous Internet-accessible error reporting system.

Science.gov (United States)

Mikuls, Ted R; Curtis, Jeffrey R; Allison, Jeroan J; Hicks, Rodney W; Saag, Kenneth G

2006-03-01

To more closely assess medication errors in gout care, we examined data from a national, Internet-accessible error reporting program over a 5-year reporting period. We examined data from the MEDMARX database, covering the period from January 1, 1999 through December 31, 2003. For allopurinol and colchicine, we examined error severity, source, type, contributing factors, and healthcare personnel involved in errors, and we detailed errors resulting in patient harm. Causes of error and the frequency of other error characteristics were compared for gout medications versus other musculoskeletal treatments using the chi-square statistic. Gout medication errors occurred in 39% (n = 273) of facilities participating in the MEDMARX program. Reported errors were predominantly from the inpatient hospital setting and related to the use of allopurinol (n = 524), followed by colchicine (n = 315), probenecid (n = 50), and sulfinpyrazone (n = 2). Compared to errors involving other musculoskeletal treatments, allopurinol and colchicine errors were more often ascribed to problems with physician prescribing (7% for other therapies versus 23-39% for allopurinol and colchicine, p < 0.0001) and less often due to problems with drug administration or nursing error (50% vs 23-27%, p < 0.0001). Our results suggest that inappropriate prescribing practices are characteristic of errors occurring with the use of allopurinol and colchicine. Physician prescribing practices are a potential target for quality improvement interventions in gout care.

Water displacement leg volumetry in clinical studies - A discussion of error sources

Science.gov (United States)

2010-01-01

Background Water displacement leg volumetry is a highly reproducible method, allowing the confirmation of efficacy of vasoactive substances. Nevertheless errors of its execution and the selection of unsuitable patients are likely to negatively affect the outcome of clinical studies in chronic venous insufficiency (CVI). Discussion Placebo controlled double-blind drug studies in CVI were searched (Cochrane Review 2005, MedLine Search until December 2007) and assessed with regard to efficacy (volume reduction of the leg), patient characteristics, and potential methodological error sources. Almost every second study reported only small drug effects (≤ 30 mL volume reduction). As the most relevant error source the conduct of volumetry was identified. Because the practical use of available equipment varies, volume differences of more than 300 mL - which is a multifold of a potential treatment effect - have been reported between consecutive measurements. Other potential error sources were insufficient patient guidance or difficulties with the transition from the Widmer CVI classification to the CEAP (Clinical Etiological Anatomical Pathophysiological) grading. Summary Patients should be properly diagnosed with CVI and selected for stable oedema and further clinical symptoms relevant for the specific study. Centres require a thorough training on the use of the volumeter and on patient guidance. Volumetry should be performed under constant conditions. The reproducibility of short term repeat measurements has to be ensured. PMID:20070899

Sensitivity of risk parameters to human errors in reactor safety study for a PWR

International Nuclear Information System (INIS)

Samanta, P.K.; Hall, R.E.; Swoboda, A.L.

1981-01-01

Sensitivities of the risk parameters, emergency safety system unavailabilities, accident sequence probabilities, release category probabilities and core melt probability were investigated for changes in the human error rates within the general methodological framework of the Reactor Safety Study (RSS) for a Pressurized Water Reactor (PWR). Impact of individual human errors were assessed both in terms of their structural importance to core melt and reliability importance on core melt probability. The Human Error Sensitivity Assessment of a PWR (HESAP) computer code was written for the purpose of this study. The code employed point estimate approach and ignored the smoothing technique applied in RSS. It computed the point estimates for the system unavailabilities from the median values of the component failure rates and proceeded in terms of point values to obtain the point estimates for the accident sequence probabilities, core melt probability, and release category probabilities. The sensitivity measure used was the ratio of the top event probability before and after the perturbation of the constituent events. Core melt probability per reactor year showed significant increase with the increase in the human error rates, but did not show similar decrease with the decrease in the human error rates due to the dominance of the hardware failures. When the Minimum Human Error Rate (M.H.E.R.) used is increased to 10 -3 , the base case human error rates start sensitivity to human errors. This effort now allows the evaluation of new error rate data along with proposed changes in the man machine interface

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

Science.gov (United States)

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

2012-09-01

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

Heuristic errors in clinical reasoning.

Science.gov (United States)

Rylander, Melanie; Guerrasio, Jeannette

2016-08-01

Errors in clinical reasoning contribute to patient morbidity and mortality. The purpose of this study was to determine the types of heuristic errors made by third-year medical students and first-year residents. This study surveyed approximately 150 clinical educators inquiring about the types of heuristic errors they observed in third-year medical students and first-year residents. Anchoring and premature closure were the two most common errors observed amongst third-year medical students and first-year residents. There was no difference in the types of errors observed in the two groups. Errors in clinical reasoning contribute to patient morbidity and mortality Clinical educators perceived that both third-year medical students and first-year residents committed similar heuristic errors, implying that additional medical knowledge and clinical experience do not affect the types of heuristic errors made. Further work is needed to help identify methods that can be used to reduce heuristic errors early in a clinician's education. © 2015 John Wiley & Sons Ltd.

Diagnostic errors in pediatric radiology

International Nuclear Information System (INIS)

Taylor, George A.; Voss, Stephan D.; Melvin, Patrice R.; Graham, Dionne A.

2011-01-01

Little information is known about the frequency, types and causes of diagnostic errors in imaging children. Our goals were to describe the patterns and potential etiologies of diagnostic error in our subspecialty. We reviewed 265 cases with clinically significant diagnostic errors identified during a 10-year period. Errors were defined as a diagnosis that was delayed, wrong or missed; they were classified as perceptual, cognitive, system-related or unavoidable; and they were evaluated by imaging modality and level of training of the physician involved. We identified 484 specific errors in the 265 cases reviewed (mean:1.8 errors/case). Most discrepancies involved staff (45.5%). Two hundred fifty-eight individual cognitive errors were identified in 151 cases (mean = 1.7 errors/case). Of these, 83 cases (55%) had additional perceptual or system-related errors. One hundred sixty-five perceptual errors were identified in 165 cases. Of these, 68 cases (41%) also had cognitive or system-related errors. Fifty-four system-related errors were identified in 46 cases (mean = 1.2 errors/case) of which all were multi-factorial. Seven cases were unavoidable. Our study defines a taxonomy of diagnostic errors in a large academic pediatric radiology practice and suggests that most are multi-factorial in etiology. Further study is needed to define effective strategies for improvement. (orig.)

Medication Errors in a Swiss Cardiovascular Surgery Department: A Cross-Sectional Study Based on a Novel Medication Error Report Method

Directory of Open Access Journals (Sweden)

Kaspar Küng

2013-01-01

Full Text Available The purpose of this study was (1 to determine frequency and type of medication errors (MEs, (2 to assess the number of MEs prevented by registered nurses, (3 to assess the consequences of ME for patients, and (4 to compare the number of MEs reported by a newly developed medication error self-reporting tool to the number reported by the traditional incident reporting system. We conducted a cross-sectional study on ME in the Cardiovascular Surgery Department of Bern University Hospital in Switzerland. Eligible registered nurses ( involving in the medication process were included. Data on ME were collected using an investigator-developed medication error self reporting tool (MESRT that asked about the occurrence and characteristics of ME. Registered nurses were instructed to complete a MESRT at the end of each shift even if there was no ME. All MESRTs were completed anonymously. During the one-month study period, a total of 987 MESRTs were returned. Of the 987 completed MESRTs, 288 (29% indicated that there had been an ME. Registered nurses reported preventing 49 (5% MEs. Overall, eight (2.8% MEs had patient consequences. The high response rate suggests that this new method may be a very effective approach to detect, report, and describe ME in hospitals.

Detected-jump-error-correcting quantum codes, quantum error designs, and quantum computation

International Nuclear Information System (INIS)

Alber, G.; Mussinger, M.; Beth, Th.; Charnes, Ch.; Delgado, A.; Grassl, M.

2003-01-01

The recently introduced detected-jump-correcting quantum codes are capable of stabilizing qubit systems against spontaneous decay processes arising from couplings to statistically independent reservoirs. These embedded quantum codes exploit classical information about which qubit has emitted spontaneously and correspond to an active error-correcting code embedded in a passive error-correcting code. The construction of a family of one-detected-jump-error-correcting quantum codes is shown and the optimal redundancy, encoding, and recovery as well as general properties of detected-jump-error-correcting quantum codes are discussed. By the use of design theory, multiple-jump-error-correcting quantum codes can be constructed. The performance of one-jump-error-correcting quantum codes under nonideal conditions is studied numerically by simulating a quantum memory and Grover's algorithm

In-plant reliability data base for nuclear plant components: a feasibility study on human error information

International Nuclear Information System (INIS)

Borkowski, R.J.; Fragola, J.R.; Schurman, D.L.; Johnson, J.W.

1984-03-01

This report documents the procedure and final results of a feasibility study which examined the usefulness of nuclear plant maintenance work requests in the IPRDS as tools for understanding human error and its influence on component failure and repair. Developed in this study were (1) a set of criteria for judging the quality of a plant maintenance record set for studying human error; (2) a scheme for identifying human errors in the maintenance records; and (3) two taxonomies (engineering-based and psychology-based) for categorizing and coding human error-related events

Learning from Errors

Directory of Open Access Journals (Sweden)

MA. Lendita Kryeziu

2015-06-01

Full Text Available “Errare humanum est”, a well known and widespread Latin proverb which states that: to err is human, and that people make mistakes all the time. However, what counts is that people must learn from mistakes. On these grounds Steve Jobs stated: “Sometimes when you innovate, you make mistakes. It is best to admit them quickly, and get on with improving your other innovations.” Similarly, in learning new language, learners make mistakes, thus it is important to accept them, learn from them, discover the reason why they make them, improve and move on. The significance of studying errors is described by Corder as: “There have always been two justifications proposed for the study of learners' errors: the pedagogical justification, namely that a good understanding of the nature of error is necessary before a systematic means of eradicating them could be found, and the theoretical justification, which claims that a study of learners' errors is part of the systematic study of the learners' language which is itself necessary to an understanding of the process of second language acquisition” (Corder, 1982; 1. Thus the importance and the aim of this paper is analyzing errors in the process of second language acquisition and the way we teachers can benefit from mistakes to help students improve themselves while giving the proper feedback.

Medication error detection in two major teaching hospitals: What are the types of errors?

Directory of Open Access Journals (Sweden)

Fatemeh Saghafi

2014-01-01

Full Text Available Background: Increasing number of reports on medication errors and relevant subsequent damages, especially in medical centers has become a growing concern for patient safety in recent decades. Patient safety and in particular, medication safety is a major concern and challenge for health care professionals around the world. Our prospective study was designed to detect prescribing, transcribing, dispensing, and administering medication errors in two major university hospitals. Materials and Methods: After choosing 20 similar hospital wards in two large teaching hospitals in the city of Isfahan, Iran, the sequence was randomly selected. Diagrams for drug distribution were drawn by the help of pharmacy directors. Direct observation technique was chosen as the method for detecting the errors. A total of 50 doses were studied in each ward to detect prescribing, transcribing and administering errors in each ward. The dispensing error was studied on 1000 doses dispensed in each hospital pharmacy. Results: A total of 8162 number of doses of medications were studied during the four stages, of which 8000 were complete data to be analyzed. 73% of prescribing orders were incomplete and did not have all six parameters (name, dosage form, dose and measuring unit, administration route, and intervals of administration. We found 15% transcribing errors. One-third of administration of medications on average was erroneous in both hospitals. Dispensing errors ranged between 1.4% and 2.2%. Conclusion: Although prescribing and administrating compromise most of the medication errors, improvements are needed in all four stages with regard to medication errors. Clear guidelines must be written and executed in both hospitals to reduce the incidence of medication errors.

A prospective, multicenter study of pharmacist activities resulting in medication error interception in the emergency department.

Science.gov (United States)

Patanwala, Asad E; Sanders, Arthur B; Thomas, Michael C; Acquisto, Nicole M; Weant, Kyle A; Baker, Stephanie N; Merritt, Erica M; Erstad, Brian L

2012-05-01

The primary objective of this study is to determine the activities of pharmacists that lead to medication error interception in the emergency department (ED). This was a prospective, multicenter cohort study conducted in 4 geographically diverse academic and community EDs in the United States. Each site had clinical pharmacy services. Pharmacists at each site recorded their medication error interceptions for 250 hours of cumulative time when present in the ED (1,000 hours total for all 4 sites). Items recorded included the activities of the pharmacist that led to medication error interception, type of orders, phase of medication use process, and type of error. Independent evaluators reviewed all medication errors. Descriptive analyses were performed for all variables. A total of 16,446 patients presented to the EDs during the study, resulting in 364 confirmed medication error interceptions by pharmacists. The pharmacists' activities that led to medication error interception were as follows: involvement in consultative activities (n=187; 51.4%), review of medication orders (n=127; 34.9%), and other (n=50; 13.7%). The types of orders resulting in medication error interceptions were written or computerized orders (n=198; 54.4%), verbal orders (n=119; 32.7%), and other (n=47; 12.9%). Most medication error interceptions occurred during the prescribing phase of the medication use process (n=300; 82.4%) and the most common type of error was wrong dose (n=161; 44.2%). Pharmacists' review of written or computerized medication orders accounts for only a third of medication error interceptions. Most medication error interceptions occur during consultative activities. Copyright © 2011. Published by Mosby, Inc.

Effects of Lexico-syntactic Errors on Teaching Materials: A Study of Textbooks Written by Nigerians

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Peace Chinwendu Israel

2014-01-01

Full Text Available This study examined lexico-syntactic errors in selected textbooks written by Nigerians. Our focus was on the educated bilinguals (acrolect who acquired their primary, secondary and tertiary education in Nigeria and the selected textbooks were textbooks published by Vanity Publishers/Press. The participants (authors cut across the three major ethnic groups in Nigeria – Hausa, Igbo and Yoruba and the selection of the textbooks covered the major disciplines of study. We adopted the descriptive research design and specifically employed the survey method to accomplish the purpose of our exploratory research.  The lexico-syntactic errors in the selected textbooks were identified and classified into various categories. These errors were not different from those identified over the years in students’ essays and exam scripts. This buttressed our argument that students are merely the conveyor belt of errors contained in the teaching material and that we can analyse the students’ lexico-syntactic errors in tandem with errors contained in the material used in teaching.

Dose variations caused by setup errors in intracranial stereotactic radiotherapy: A PRESAGE study

International Nuclear Information System (INIS)

Teng, Kieyin; Gagliardi, Frank; Alqathami, Mamdooh; Ackerly, Trevor; Geso, Moshi

2014-01-01

Stereotactic radiotherapy (SRT) requires tight margins around the tumor, thus producing a steep dose gradient between the tumor and the surrounding healthy tissue. Any setup errors might become clinically significant. To date, no study has been performed to evaluate the dosimetric variations caused by setup errors with a 3-dimensional dosimeter, the PRESAGE. This research aimed to evaluate the potential effect that setup errors have on the dose distribution of intracranial SRT. Computed tomography (CT) simulation of a CIRS radiosurgery head phantom was performed with 1.25-mm slice thickness. An ideal treatment plan was generated using Brainlab iPlan. A PRESAGE was made for every treatment with and without errors. A prescan using the optical CT scanner was carried out. Before treatment, the phantom was imaged using Brainlab ExacTrac. Actual radiotherapy treatments with and without errors were carried out with the Novalis treatment machine. Postscan was performed with an optical CT scanner to analyze the dose irradiation. The dose variation between treatments with and without errors was determined using a 3-dimensional gamma analysis. Errors are clinically insignificant when the passing ratio of the gamma analysis is 95% and above. Errors were clinically significant when the setup errors exceeded a 0.7-mm translation and a 0.5° rotation. The results showed that a 3-mm translation shift in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions and 2° couch rotation produced a passing ratio of 53.1%. Translational and rotational errors of 1.5 mm and 1°, respectively, generated a passing ratio of 62.2%. Translation shift of 0.7 mm in the directions of SI, RL, and AP and a 0.5° couch rotation produced a passing ratio of 96.2%. Preventing the occurrences of setup errors in intracranial SRT treatment is extremely important as errors greater than 0.7 mm and 0.5° alter the dose distribution. The geometrical displacements affect dose delivery

A prospective three-step intervention study to prevent medication errors in drug handling in paediatric care.

Science.gov (United States)

Niemann, Dorothee; Bertsche, Astrid; Meyrath, David; Koepf, Ellen D; Traiser, Carolin; Seebald, Katja; Schmitt, Claus P; Hoffmann, Georg F; Haefeli, Walter E; Bertsche, Thilo

2015-01-01

To prevent medication errors in drug handling in a paediatric ward. One in five preventable adverse drug events in hospitalised children is caused by medication errors. Errors in drug prescription have been studied frequently, but data regarding drug handling, including drug preparation and administration, are scarce. A three-step intervention study including monitoring procedure was used to detect and prevent medication errors in drug handling. After approval by the ethics committee, pharmacists monitored drug handling by nurses on an 18-bed paediatric ward in a university hospital prior to and following each intervention step. They also conducted a questionnaire survey aimed at identifying knowledge deficits. Each intervention step targeted different causes of errors. The handout mainly addressed knowledge deficits, the training course addressed errors caused by rule violations and slips, and the reference book addressed knowledge-, memory- and rule-based errors. The number of patients who were subjected to at least one medication error in drug handling decreased from 38/43 (88%) to 25/51 (49%) following the third intervention, and the overall frequency of errors decreased from 527 errors in 581 processes (91%) to 116/441 (26%). The issue of the handout reduced medication errors caused by knowledge deficits regarding, for instance, the correct 'volume of solvent for IV drugs' from 49-25%. Paediatric drug handling is prone to errors. A three-step intervention effectively decreased the high frequency of medication errors by addressing the diversity of their causes. Worldwide, nurses are in charge of drug handling, which constitutes an error-prone but often-neglected step in drug therapy. Detection and prevention of errors in daily routine is necessary for a safe and effective drug therapy. Our three-step intervention reduced errors and is suitable to be tested in other wards and settings. © 2014 John Wiley & Sons Ltd.

Prevalence of refractive errors in the European adult population: the Gutenberg Health Study (GHS).

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Wolfram, Christian; Höhn, René; Kottler, Ulrike; Wild, Philipp; Blettner, Maria; Bühren, Jens; Pfeiffer, Norbert; Mirshahi, Alireza

2014-07-01

To study the distribution of refractive errors among adults of European descent. Population-based eye study in Germany with 15010 participants aged 35-74 years. The study participants underwent a detailed ophthalmic examination according to a standardised protocol. Refractive error was determined by an automatic refraction device (Humphrey HARK 599) without cycloplegia. Definitions for the analysis were myopia +0.5 D, astigmatism >0.5 cylinder D and anisometropia >1.0 D difference in the spherical equivalent between the eyes. Exclusion criterion was previous cataract or refractive surgery. 13959 subjects were eligible. Refractive errors ranged from -21.5 to +13.88 D. Myopia was present in 35.1% of this study sample, hyperopia in 31.8%, astigmatism in 32.3% and anisometropia in 13.5%. The prevalence of myopia decreased, while the prevalence of hyperopia, astigmatism and anisometropia increased with age. 3.5% of the study sample had no refractive correction for their ametropia. Refractive errors affect the majority of the population. The Gutenberg Health Study sample contains more myopes than other study cohorts in adult populations. Our findings do not support the hypothesis of a generally lower prevalence of myopia among adults in Europe as compared with East Asia.

The use of adaptive radiation therapy to reduce setup error: a prospective clinical study

International Nuclear Information System (INIS)

Yan Di; Wong, John; Vicini, Frank; Robertson, John; Horwitz, Eric; Brabbins, Donald; Cook, Carla; Gustafson, Gary; Stromberg, Jannifer; Martinez, Alvaro

1996-01-01

Purpose: Adaptive Radiation Therapy (ART) is a closed-loop feedback process where each patients treatment is adaptively optimized according to the individual variation information measured during the course of treatment. The process aims to maximize the benefits of treatment for the individual patient. A prospective study is currently being conducted to test the feasibility and effectiveness of ART for clinical use. The present study is limited to compensating the effects of systematic setup error. Methods and Materials: The study includes 20 patients treated on a linear accelerator equipped with a computer controlled multileaf collimator (MLC) and a electronic portal imaging device (EPID). Alpha cradles are used to immobilize those patients treated for disease in the thoracic and abdominal regions, and thermal plastic masks for the head and neck. Portal images are acquired daily. Setup error of each treatment field is quantified off-line every day. As determined from an earlier retrospective study of different clinical sites, the measured setup variation from the first 4 to 9 days, are used to estimate systematic setup error and the standard deviation of random setup error for each field. Setup adjustment is made if estimated systematic setup error of the treatment field was larger than or equal to 2 mm. Instead of the conventional approach of repositioning the patient, setup correction is implemented by reshaping MLC to compensate for the estimated systematic error. The entire process from analysis of portal images to the implementation of the modified MLC field is performed via computer network. Systematic and random setup errors of the treatment after adjustment are compared with those prior to adjustment. Finally, the frequency distributions of block overlap cumulated throughout the treatment course are evaluated. Results: Sixty-seven percent of all treatment fields were reshaped to compensate for the estimated systematic errors. At the time of this writing

[Responsibility due to medication errors in France: a study based on SHAM insurance data].

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Theissen, A; Orban, J-C; Fuz, F; Guerin, J-P; Flavin, P; Albertini, S; Maricic, S; Saquet, D; Niccolai, P

2015-03-01

The safe medication practices at the hospital constitute a major public health problem. Drug supply chain is a complex process, potentially source of errors and damages for the patient. SHAM insurances are the biggest French provider of medical liability insurances and a relevant source of data on the health care complications. The main objective of the study was to analyze the type and cause of medication errors declared to SHAM and having led to a conviction by a court. We did a retrospective study on insurance claims provided by SHAM insurances with a medication error and leading to a condemnation over a 6-year period (between 2005 and 2010). Thirty-one cases were analysed, 21 for scheduled activity and 10 for emergency activity. Consequences of claims were mostly serious (12 deaths, 14 serious complications, 5 simple complications). The types of medication errors were a drug monitoring error (11 cases), an administration error (5 cases), an overdose (6 cases), an allergy (4 cases), a contraindication (3 cases) and an omission (2 cases). Intravenous route of administration was involved in 19 of 31 cases (61%). The causes identified by the court expert were an error related to service organization (11), an error related to medical practice (11) or nursing practice (13). Only one claim was due to the hospital pharmacy. The claim related to drug supply chain is infrequent but potentially serious. These data should help strengthen quality approach in risk management. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Medication errors in home care: a qualitative focus group study.

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Berland, Astrid; Bentsen, Signe Berit

2017-11-01

To explore registered nurses' experiences of medication errors and patient safety in home care. The focus of care for older patients has shifted from institutional care towards a model of home care. Medication errors are common in this situation and can result in patient morbidity and mortality. An exploratory qualitative design with focus group interviews was used. Four focus group interviews were conducted with 20 registered nurses in home care. The data were analysed using content analysis. Five categories were identified as follows: lack of information, lack of competence, reporting medication errors, trade name products vs. generic name products, and improving routines. Medication errors occur frequently in home care and can threaten the safety of patients. Insufficient exchange of information and poor communication between the specialist and home-care health services, and between general practitioners and healthcare workers can lead to medication errors. A lack of competence in healthcare workers can also lead to medication errors. To prevent these, it is important that there should be up-to-date information and communication between healthcare workers during the transfer of patients from specialist to home care. Ensuring competence among healthcare workers with regard to medication is also important. In addition, there should be openness and accurate reporting of medication errors, as well as in setting routines for the preparation, alteration and administration of medicines. To prevent medication errors in home care, up-to-date information and communication between healthcare workers is important when patients are transferred from specialist to home care. It is also important to ensure adequate competence with regard to medication, and that there should be openness when medication errors occur, as well as in setting routines for the preparation, alteration and administration of medications. © 2017 John Wiley & Sons Ltd.

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

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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.

Modeling misidentification errors in capture-recapture studies using photographic identification of evolving marks

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Yoshizaki, J.; Pollock, K.H.; Brownie, C.; Webster, R.A.

2009-01-01

Misidentification of animals is potentially important when naturally existing features (natural tags) are used to identify individual animals in a capture-recapture study. Photographic identification (photoID) typically uses photographic images of animals' naturally existing features as tags (photographic tags) and is subject to two main causes of identification errors: those related to quality of photographs (non-evolving natural tags) and those related to changes in natural marks (evolving natural tags). The conventional methods for analysis of capture-recapture data do not account for identification errors, and to do so requires a detailed understanding of the misidentification mechanism. Focusing on the situation where errors are due to evolving natural tags, we propose a misidentification mechanism and outline a framework for modeling the effect of misidentification in closed population studies. We introduce methods for estimating population size based on this model. Using a simulation study, we show that conventional estimators can seriously overestimate population size when errors due to misidentification are ignored, and that, in comparison, our new estimators have better properties except in cases with low capture probabilities (<0.2) or low misidentification rates (<2.5%). ?? 2009 by the Ecological Society of America.

Learning from Errors

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Metcalfe, Janet

2017-01-01

Although error avoidance during learning appears to be the rule in American classrooms, laboratory studies suggest that it may be a counterproductive strategy, at least for neurologically typical students. Experimental investigations indicate that errorful learning followed by corrective feedback is beneficial to learning. Interestingly, the…

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

Science.gov (United States)

Yang, F.; Dong, Z. H.

2017-10-01

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

Error-related potentials during continuous feedback: using EEG to detect errors of different type and severity

Science.gov (United States)

Spüler, Martin; Niethammer, Christian

2015-01-01

When a person recognizes an error during a task, an error-related potential (ErrP) can be measured as response. It has been shown that ErrPs can be automatically detected in tasks with time-discrete feedback, which is widely applied in the field of Brain-Computer Interfaces (BCIs) for error correction or adaptation. However, there are only a few studies that concentrate on ErrPs during continuous feedback. With this study, we wanted to answer three different questions: (i) Can ErrPs be measured in electroencephalography (EEG) recordings during a task with continuous cursor control? (ii) Can ErrPs be classified using machine learning methods and is it possible to discriminate errors of different origins? (iii) Can we use EEG to detect the severity of an error? To answer these questions, we recorded EEG data from 10 subjects during a video game task and investigated two different types of error (execution error, due to inaccurate feedback; outcome error, due to not achieving the goal of an action). We analyzed the recorded data to show that during the same task, different kinds of error produce different ErrP waveforms and have a different spectral response. This allows us to detect and discriminate errors of different origin in an event-locked manner. By utilizing the error-related spectral response, we show that also a continuous, asynchronous detection of errors is possible. Although the detection of error severity based on EEG was one goal of this study, we did not find any significant influence of the severity on the EEG. PMID:25859204

Error-related potentials during continuous feedback: using EEG to detect errors of different type and severity

Directory of Open Access Journals (Sweden)

Martin eSpüler

2015-03-01

Full Text Available When a person recognizes an error during a task, an error-related potential (ErrP can be measured as response. It has been shown that ErrPs can be automatically detected in tasks with time-discrete feedback, which is widely applied in the field of Brain-Computer Interfaces (BCIs for error correction or adaptation. However, there are only a few studies that concentrate on ErrPs during continuous feedback.With this study, we wanted to answer three different questions: (i Can ErrPs be measured in electroencephalography (EEG recordings during a task with continuous cursor control? (ii Can ErrPs be classified using machine learning methods and is it possible to discriminate errors of different origins? (iii Can we use EEG to detect the severity of an error? To answer these questions, we recorded EEG data from 10 subjects during a video game task and investigated two different types of error (execution error, due to inaccurate feedback; outcome error, due to not achieving the goal of an action. We analyzed the recorded data to show that during the same task, different kinds of error produce different ErrP waveforms and have a different spectral response. This allows us to detect and discriminate errors of different origin in an event-locked manner. By utilizing the error-related spectral response, we show that also a continuous, asynchronous detection of errors is possible.Although the detection of error severity based on EEG was one goal of this study, we did not find any significant influence of the severity on the EEG.

Barriers to medical error reporting

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Jalal Poorolajal

2015-01-01

Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

Learning time-dependent noise to reduce logical errors: real time error rate estimation in quantum error correction

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Huo, Ming-Xia; Li, Ying

2017-12-01

Quantum error correction is important to quantum information processing, which allows us to reliably process information encoded in quantum error correction codes. Efficient quantum error correction benefits from the knowledge of error rates. We propose a protocol for monitoring error rates in real time without interrupting the quantum error correction. Any adaptation of the quantum error correction code or its implementation circuit is not required. The protocol can be directly applied to the most advanced quantum error correction techniques, e.g. surface code. A Gaussian processes algorithm is used to estimate and predict error rates based on error correction data in the past. We find that using these estimated error rates, the probability of error correction failures can be significantly reduced by a factor increasing with the code distance.

Human Errors in Decision Making

OpenAIRE

Mohamad, Shahriari; Aliandrina, Dessy; Feng, Yan

2005-01-01

The aim of this paper was to identify human errors in decision making process. The study was focused on a research question such as: what could be the human error as a potential of decision failure in evaluation of the alternatives in the process of decision making. Two case studies were selected from the literature and analyzed to find the human errors contribute to decision fail. Then the analysis of human errors was linked with mental models in evaluation of alternative step. The results o...

Pilotaje en la detección de errores de prescripción de citostáticos Pilot study in the detection of errors in cytostatics prescription

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María Antonieta Arbesú Michelena

2004-12-01

Full Text Available Dada la alta toxicidad de los citostáticos, resulta importante conocer la prevalencia de los errores de medicación ya que pueden provocar graves consecuencias en la respuesta al tratamiento de cada paciente. Con el objetivo de trazar una estrategia relacionada con la disminución de los posibles errores de prescripción se realizó un estudio piloto durante la semana comprendida entre el 15 y el 21 de diciembre de 2003, en el Servicio Quimioterapia Oncológica del Instituto de Oncología y Radiobiología, en 43 órdenes médicas. Los errores para el presente trabajo se clasificaron en errores por omisión (que dificultan la comprobación por parte del farmacéutico y errores de incorrección (que pueden ser potencialmente graves para el paciente. El total de errores fue de 299; en el caso de los errores por omisión, se destacan la no firma por el facultativo en las 43 prescripciones, así como el uso de abreviaturas, siglas o nombres comerciales en el 88,4 %. En relación con los errores graves se aprecia la no inclusión del peso y la talla en ninguna orden médica, la superficie corporal (sc errónea por encima en 15 casos (34,8 %, la subdosificación en 41 ocasiones (47,7 % y la no correspondencia del Protocolo según las Normas Institucionales con 17 incorrecciones. Se pudo conocer que la ocurrencia de errores de prescripción es alta en el Servicio, lo que demuestra que es importante protocolizar las órdenes médicas, lo que permitirá la disminución en el porcentaje de errores detectados en este estudio piloto y continuar profundizando al respecto.Due to the high toxicity of cytostatics it is important to know the prevalence of errors in medication, since they can cause serious consequences in the reponse to the treatment of every patient. In order to lay down a strategy related to the reduction of the possible errors in prescription, a pilot study was conducted in December 15-21, 2003, at the Oncological Chemotherapy Service of the

Awareness of technology-induced errors and processes for identifying and preventing such errors.

Science.gov (United States)

Bellwood, Paule; Borycki, Elizabeth M; Kushniruk, Andre W

2015-01-01

There is a need to determine if organizations working with health information technology are aware of technology-induced errors and how they are addressing and preventing them. The purpose of this study was to: a) determine the degree of technology-induced error awareness in various Canadian healthcare organizations, and b) identify those processes and procedures that are currently in place to help address, manage, and prevent technology-induced errors. We identified a lack of technology-induced error awareness among participants. Participants identified there was a lack of well-defined procedures in place for reporting technology-induced errors, addressing them when they arise, and preventing them.

Study of on-machine error identification and compensation methods for micro machine tools

International Nuclear Information System (INIS)

Wang, Shih-Ming; Yu, Han-Jen; Lee, Chun-Yi; Chiu, Hung-Sheng

2016-01-01

Micro machining plays an important role in the manufacturing of miniature products which are made of various materials with complex 3D shapes and tight machining tolerance. To further improve the accuracy of a micro machining process without increasing the manufacturing cost of a micro machine tool, an effective machining error measurement method and a software-based compensation method are essential. To avoid introducing additional errors caused by the re-installment of the workpiece, the measurement and compensation method should be on-machine conducted. In addition, because the contour of a miniature workpiece machined with a micro machining process is very tiny, the measurement method should be non-contact. By integrating the image re-constructive method, camera pixel correction, coordinate transformation, the error identification algorithm, and trajectory auto-correction method, a vision-based error measurement and compensation method that can on-machine inspect the micro machining errors and automatically generate an error-corrected numerical control (NC) program for error compensation was developed in this study. With the use of the Canny edge detection algorithm and camera pixel calibration, the edges of the contour of a machined workpiece were identified and used to re-construct the actual contour of the work piece. The actual contour was then mapped to the theoretical contour to identify the actual cutting points and compute the machining errors. With the use of a moving matching window and calculation of the similarity between the actual and theoretical contour, the errors between the actual cutting points and theoretical cutting points were calculated and used to correct the NC program. With the use of the error-corrected NC program, the accuracy of a micro machining process can be effectively improved. To prove the feasibility and effectiveness of the proposed methods, micro-milling experiments on a micro machine tool were conducted, and the results

Medication errors: prescribing faults and prescription errors.

Science.gov (United States)

Velo, Giampaolo P; Minuz, Pietro

2009-06-01

1. Medication errors are common in general practice and in hospitals. Both errors in the act of writing (prescription errors) and prescribing faults due to erroneous medical decisions can result in harm to patients. 2. Any step in the prescribing process can generate errors. Slips, lapses, or mistakes are sources of errors, as in unintended omissions in the transcription of drugs. Faults in dose selection, omitted transcription, and poor handwriting are common. 3. Inadequate knowledge or competence and incomplete information about clinical characteristics and previous treatment of individual patients can result in prescribing faults, including the use of potentially inappropriate medications. 4. An unsafe working environment, complex or undefined procedures, and inadequate communication among health-care personnel, particularly between doctors and nurses, have been identified as important underlying factors that contribute to prescription errors and prescribing faults. 5. Active interventions aimed at reducing prescription errors and prescribing faults are strongly recommended. These should be focused on the education and training of prescribers and the use of on-line aids. The complexity of the prescribing procedure should be reduced by introducing automated systems or uniform prescribing charts, in order to avoid transcription and omission errors. Feedback control systems and immediate review of prescriptions, which can be performed with the assistance of a hospital pharmacist, are also helpful. Audits should be performed periodically.

Perceptual learning eases crowding by reducing recognition errors but not position errors.

Science.gov (United States)

Xiong, Ying-Zi; Yu, Cong; Zhang, Jun-Yun

2015-08-01

When an observer reports a letter flanked by additional letters in the visual periphery, the response errors (the crowding effect) may result from failure to recognize the target letter (recognition errors), from mislocating a correctly recognized target letter at a flanker location (target misplacement errors), or from reporting a flanker as the target letter (flanker substitution errors). Crowding can be reduced through perceptual learning. However, it is not known how perceptual learning operates to reduce crowding. In this study we trained observers with a partial-report task (Experiment 1), in which they reported the central target letter of a three-letter string presented in the visual periphery, or a whole-report task (Experiment 2), in which they reported all three letters in order. We then assessed the impact of training on recognition of both unflanked and flanked targets, with particular attention to how perceptual learning affected the types of errors. Our results show that training improved target recognition but not single-letter recognition, indicating that training indeed affected crowding. However, training did not reduce target misplacement errors or flanker substitution errors. This dissociation between target recognition and flanker substitution errors supports the view that flanker substitution may be more likely a by-product (due to response bias), rather than a cause, of crowding. Moreover, the dissociation is not consistent with hypothesized mechanisms of crowding that would predict reduced positional errors.

(How) do we learn from errors? A prospective study of the link between the ward's learning practices and medication administration errors.

Science.gov (United States)

Drach-Zahavy, A; Somech, A; Admi, H; Peterfreund, I; Peker, H; Priente, O

2014-03-01

Attention in the ward should shift from preventing medication administration errors to managing them. Nevertheless, little is known in regard with the practices nursing wards apply to learn from medication administration errors as a means of limiting them. To test the effectiveness of four types of learning practices, namely, non-integrated, integrated, supervisory and patchy learning practices in limiting medication administration errors. Data were collected from a convenient sample of 4 hospitals in Israel by multiple methods (observations and self-report questionnaires) at two time points. The sample included 76 wards (360 nurses). Medication administration error was defined as any deviation from prescribed medication processes and measured by a validated structured observation sheet. Wards' use of medication administration technologies, location of the medication station, and workload were observed; learning practices and demographics were measured by validated questionnaires. Results of the mixed linear model analysis indicated that the use of technology and quiet location of the medication cabinet were significantly associated with reduced medication administration errors (estimate=.03, perrors (estimate=.04, plearning practices, supervisory learning was the only practice significantly linked to reduced medication administration errors (estimate=-.04, plearning were significantly linked to higher levels of medication administration errors (estimate=-.03, plearning was not associated with it (p>.05). How wards manage errors might have implications for medication administration errors beyond the effects of typical individual, organizational and technology risk factors. Head nurse can facilitate learning from errors by "management by walking around" and monitoring nurses' medication administration behaviors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reward positivity: Reward prediction error or salience prediction error?

Science.gov (United States)

Heydari, Sepideh; Holroyd, Clay B

2016-08-01

The reward positivity is a component of the human ERP elicited by feedback stimuli in trial-and-error learning and guessing tasks. A prominent theory holds that the reward positivity reflects a reward prediction error signal that is sensitive to outcome valence, being larger for unexpected positive events relative to unexpected negative events (Holroyd & Coles, 2002). Although the theory has found substantial empirical support, most of these studies have utilized either monetary or performance feedback to test the hypothesis. However, in apparent contradiction to the theory, a recent study found that unexpected physical punishments also elicit the reward positivity (Talmi, Atkinson, & El-Deredy, 2013). The authors of this report argued that the reward positivity reflects a salience prediction error rather than a reward prediction error. To investigate this finding further, in the present study participants navigated a virtual T maze and received feedback on each trial under two conditions. In a reward condition, the feedback indicated that they would either receive a monetary reward or not and in a punishment condition the feedback indicated that they would receive a small shock or not. We found that the feedback stimuli elicited a typical reward positivity in the reward condition and an apparently delayed reward positivity in the punishment condition. Importantly, this signal was more positive to the stimuli that predicted the omission of a possible punishment relative to stimuli that predicted a forthcoming punishment, which is inconsistent with the salience hypothesis. © 2016 Society for Psychophysiological Research.

Study of maintenance skill-work based on PSFs and error category

International Nuclear Information System (INIS)

Nagata, Manabu; Yukimachi, Takeo; Hasegawa, Toshio

2001-01-01

In this investigation, the skill-types of skill-work are clarified according to the human error data on the maintenance works at nuclear power plants. At first, the causal PSFs of the errors are extracted from the data and some of the skill-types are characterized as results from factor analysis. Moreover, the skill-work model is reexamined on the basis of the contents of the human error data and the error category corresponding to the data. Furthermore, integrating the tendency of the causal PSFs and the actual error category concerning each skill-type, an extended skill-work model was developed with a flow-chart representation as a tentative stage of the investigation. (author)

The Errors of Our Ways: Understanding Error Representations in Cerebellar-Dependent Motor Learning.

Science.gov (United States)

Popa, Laurentiu S; Streng, Martha L; Hewitt, Angela L; Ebner, Timothy J

2016-04-01

The cerebellum is essential for error-driven motor learning and is strongly implicated in detecting and correcting for motor errors. Therefore, elucidating how motor errors are represented in the cerebellum is essential in understanding cerebellar function, in general, and its role in motor learning, in particular. This review examines how motor errors are encoded in the cerebellar cortex in the context of a forward internal model that generates predictions about the upcoming movement and drives learning and adaptation. In this framework, sensory prediction errors, defined as the discrepancy between the predicted consequences of motor commands and the sensory feedback, are crucial for both on-line movement control and motor learning. While many studies support the dominant view that motor errors are encoded in the complex spike discharge of Purkinje cells, others have failed to relate complex spike activity with errors. Given these limitations, we review recent findings in the monkey showing that complex spike modulation is not necessarily required for motor learning or for simple spike adaptation. Also, new results demonstrate that the simple spike discharge provides continuous error signals that both lead and lag the actual movements in time, suggesting errors are encoded as both an internal prediction of motor commands and the actual sensory feedback. These dual error representations have opposing effects on simple spike discharge, consistent with the signals needed to generate sensory prediction errors used to update a forward internal model.

Calculation errors of Set-up in patients with tumor location of prostate. Exploratory study; Calculo de errores de Set-up en pacientes con localizacion tumoral de prostata. Estudio exploratorio

Energy Technology Data Exchange (ETDEWEB)

Donis Gil, S.; Robayna Duque, B. E.; Jimenez Sosa, A.; Hernandez Armas, O.; Gonzalez Martin, A. E.; Hernandez Armas, J.

2013-07-01

The calculation of SM is done from errors in positioning (set-up). These errors are calculated from movements in 3D of the patient. This paper is an exploratory study of 20 patients with tumor location of prostate in which errors of set-up for two protocols of work are evaluated. (Author)

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

On the importance of Task 1 and error performance measures in PRP dual-task studies

Science.gov (United States)

Strobach, Tilo; Schütz, Anja; Schubert, Torsten

2015-01-01

The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects. PMID:25904890

On the importance of Task 1 and error performance measures in PRP dual-task studies.

Science.gov (United States)

Strobach, Tilo; Schütz, Anja; Schubert, Torsten

2015-01-01

The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

On the importance of Task 1 and error performance measures in PRP dual-task studies

Directory of Open Access Journals (Sweden)

Tilo eStrobach

2015-04-01

Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

Scaling prediction errors to reward variability benefits error-driven learning in humans.

Science.gov (United States)

Diederen, Kelly M J; Schultz, Wolfram

2015-09-01

Effective error-driven learning requires individuals to adapt learning to environmental reward variability. The adaptive mechanism may involve decays in learning rate across subsequent trials, as shown previously, and rescaling of reward prediction errors. The present study investigated the influence of prediction error scaling and, in particular, the consequences for learning performance. Participants explicitly predicted reward magnitudes that were drawn from different probability distributions with specific standard deviations. By fitting the data with reinforcement learning models, we found scaling of prediction errors, in addition to the learning rate decay shown previously. Importantly, the prediction error scaling was closely related to learning performance, defined as accuracy in predicting the mean of reward distributions, across individual participants. In addition, participants who scaled prediction errors relative to standard deviation also presented with more similar performance for different standard deviations, indicating that increases in standard deviation did not substantially decrease "adapters'" accuracy in predicting the means of reward distributions. However, exaggerated scaling beyond the standard deviation resulted in impaired performance. Thus efficient adaptation makes learning more robust to changing variability. Copyright © 2015 the American Physiological Society.

Abnormal error monitoring in math-anxious individuals: evidence from error-related brain potentials.

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Macarena Suárez-Pellicioni

Full Text Available This study used event-related brain potentials to investigate whether math anxiety is related to abnormal error monitoring processing. Seventeen high math-anxious (HMA and seventeen low math-anxious (LMA individuals were presented with a numerical and a classical Stroop task. Groups did not differ in terms of trait or state anxiety. We found enhanced error-related negativity (ERN in the HMA group when subjects committed an error on the numerical Stroop task, but not on the classical Stroop task. Groups did not differ in terms of the correct-related negativity component (CRN, the error positivity component (Pe, classical behavioral measures or post-error measures. The amplitude of the ERN was negatively related to participants' math anxiety scores, showing a more negative amplitude as the score increased. Moreover, using standardized low resolution electromagnetic tomography (sLORETA we found greater activation of the insula in errors on a numerical task as compared to errors in a non-numerical task only for the HMA group. The results were interpreted according to the motivational significance theory of the ERN.

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.

Human Error Analysis in a Permit to Work System: A Case Study in a Chemical Plant

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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.

[Medical errors: inevitable but preventable].

Science.gov (United States)

Giard, R W

2001-10-27

Medical errors are increasingly reported in the lay press. Studies have shown dramatic error rates of 10 percent or even higher. From a methodological point of view, studying the frequency and causes of medical errors is far from simple. Clinical decisions on diagnostic or therapeutic interventions are always taken within a clinical context. Reviewing outcomes of interventions without taking into account both the intentions and the arguments for a particular action will limit the conclusions from a study on the rate and preventability of errors. The interpretation of the preventability of medical errors is fraught with difficulties and probably highly subjective. Blaming the doctor personally does not do justice to the actual situation and especially the organisational framework. Attention for and improvement of the organisational aspects of error are far more important then litigating the person. To err is and will remain human and if we want to reduce the incidence of faults we must be able to learn from our mistakes. That requires an open attitude towards medical mistakes, a continuous effort in their detection, a sound analysis and, where feasible, the institution of preventive measures.

SIMulation of Medication Error induced by Clinical Trial drug labeling: the SIMME-CT study.

Science.gov (United States)

Dollinger, Cecile; Schwiertz, Vérane; Sarfati, Laura; Gourc-Berthod, Chloé; Guédat, Marie-Gabrielle; Alloux, Céline; Vantard, Nicolas; Gauthier, Noémie; He, Sophie; Kiouris, Elena; Caffin, Anne-Gaelle; Bernard, Delphine; Ranchon, Florence; Rioufol, Catherine

2016-06-01

To assess the impact of investigational drug labels on the risk of medication error in drug dispensing. A simulation-based learning program focusing on investigational drug dispensing was conducted. The study was undertaken in an Investigational Drugs Dispensing Unit of a University Hospital of Lyon, France. Sixty-three pharmacy workers (pharmacists, residents, technicians or students) were enrolled. Ten risk factors were selected concerning label information or the risk of confusion with another clinical trial. Each risk factor was scored independently out of 5: the higher the score, the greater the risk of error. From 400 labels analyzed, two groups were selected for the dispensing simulation: 27 labels with high risk (score ≥3) and 27 with low risk (score ≤2). Each question in the learning program was displayed as a simulated clinical trial prescription. Medication error was defined as at least one erroneous answer (i.e. error in drug dispensing). For each question, response times were collected. High-risk investigational drug labels correlated with medication error and slower response time. Error rates were significantly 5.5-fold higher for high-risk series. Error frequency was not significantly affected by occupational category or experience in clinical trials. SIMME-CT is the first simulation-based learning tool to focus on investigational drug labels as a risk factor for medication error. SIMME-CT was also used as a training tool for staff involved in clinical research, to develop medication error risk awareness and to validate competence in continuing medical education. © The Author 2016. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

Challenge and Error: Critical Events and Attention-Related Errors

Science.gov (United States)

Cheyne, James Allan; Carriere, Jonathan S. A.; Solman, Grayden J. F.; Smilek, Daniel

2011-01-01

Attention lapses resulting from reactivity to task challenges and their consequences constitute a pervasive factor affecting everyday performance errors and accidents. A bidirectional model of attention lapses (error [image omitted] attention-lapse: Cheyne, Solman, Carriere, & Smilek, 2009) argues that errors beget errors by generating attention…

Error forecasting schemes of error correction at receiver

International Nuclear Information System (INIS)

Bhunia, C.T.

2007-08-01

To combat error in computer communication networks, ARQ (Automatic Repeat Request) techniques are used. Recently Chakraborty has proposed a simple technique called the packet combining scheme in which error is corrected at the receiver from the erroneous copies. Packet Combining (PC) scheme fails: (i) when bit error locations in erroneous copies are the same and (ii) when multiple bit errors occur. Both these have been addressed recently by two schemes known as Packet Reversed Packet Combining (PRPC) Scheme, and Modified Packet Combining (MPC) Scheme respectively. In the letter, two error forecasting correction schemes are reported, which in combination with PRPC offer higher throughput. (author)

Apology in cases of medical error disclosure: Thoughts based on a preliminary study.

Science.gov (United States)

Dahan, Sonia; Ducard, Dominique; Caeymaex, Laurence

2017-01-01

Disclosing medical errors is considered necessary by patients, ethicists, and health care professionals. Literature insists on the framing of this disclosure and describes the apology as appropriate and necessary. However, this policy seems difficult to put into practice. Few works have explored the function and meaning of the apology. The aim of this study was to explore the role ascribed to apology in communication between healthcare professionals and patients when disclosing a medical error, and to discuss these findings using a linguistic and philosophical perspective. Qualitative exploratory study, based on face-to-face semi-structured interviews, with seven physicians in a neonatal unit in France. Discourse analysis. Four themes emerged. Difference between apology in everyday life and in the medical encounter; place of the apology in the process of disclosure together with explanations, regrets, empathy and ways to avoid repeating the error; effects of the apology were to allow the patient-physician relationship undermined by the error, to be maintained, responsibility to be accepted, the first steps towards forgiveness to be taken, and a less hierarchical doctor-patient relationship to be created; ways of expressing apology ("I am sorry") reflected regrets and empathy more than an explicit apology. This study highlights how the act of apology can be seen as a "language act" as described by philosophers Austin and Searle, and how it functions as a technique for making amends following a wrongdoing and as an action undertaken in order that neither party should lose face, thus echoing the sociologist Goffmann's interaction theory. This interpretation also accords with the views of Lazare, for whom the function of apology is a restoration of dignity after the humiliation of the error. This approach to the apology illustrates how meaning and impact of real-life language acts can be clarified by philosophical and sociological ideas.

Neural Bases of Unconscious Error Detection in a Chinese Anagram Solution Task: Evidence from ERP Study.

Directory of Open Access Journals (Sweden)

Hua-Zhan Yin

Full Text Available In everyday life, error monitoring and processing are important for improving ongoing performance in response to a changing environment. However, detecting an error is not always a conscious process. The temporal activation patterns of brain areas related to cognitive control in the absence of conscious awareness of an error remain unknown. In the present study, event-related potentials (ERPs in the brain were used to explore the neural bases of unconscious error detection when subjects solved a Chinese anagram task. Our ERP data showed that the unconscious error detection (UED response elicited a more negative ERP component (N2 than did no error (NE and detect error (DE responses in the 300-400-ms time window, and the DE elicited a greater late positive component (LPC than did the UED and NE in the 900-1200-ms time window after the onset of the anagram stimuli. Taken together with the results of dipole source analysis, the N2 (anterior cingulate cortex might reflect unconscious/automatic conflict monitoring, and the LPC (superior/medial frontal gyrus might reflect conscious error recognition.

Thermodynamics of Error Correction

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Pablo Sartori

2015-12-01

Full Text Available Information processing at the molecular scale is limited by thermal fluctuations. This can cause undesired consequences in copying information since thermal noise can lead to errors that can compromise the functionality of the copy. For example, a high error rate during DNA duplication can lead to cell death. Given the importance of accurate copying at the molecular scale, it is fundamental to understand its thermodynamic features. In this paper, we derive a universal expression for the copy error as a function of entropy production and work dissipated by the system during wrong incorporations. Its derivation is based on the second law of thermodynamics; hence, its validity is independent of the details of the molecular machinery, be it any polymerase or artificial copying device. Using this expression, we find that information can be copied in three different regimes. In two of them, work is dissipated to either increase or decrease the error. In the third regime, the protocol extracts work while correcting errors, reminiscent of a Maxwell demon. As a case study, we apply our framework to study a copy protocol assisted by kinetic proofreading, and show that it can operate in any of these three regimes. We finally show that, for any effective proofreading scheme, error reduction is limited by the chemical driving of the proofreading reaction.

Prevalence and risk factors of undercorrected refractive errors among Singaporean Malay adults: the Singapore Malay Eye Study.

Science.gov (United States)

Rosman, Mohamad; Wong, Tien Y; Tay, Wan-Ting; Tong, Louis; Saw, Seang-Mei

2009-08-01

To describe the prevalence and the risk factors of undercorrected refractive error in an adult urban Malay population. This population-based, cross-sectional study was conducted in Singapore in 3280 Malay adults, aged 40 to 80 years. All individuals were examined at a centralized clinic and underwent standardized interviews and assessment of refractive errors and presenting and best corrected visual acuities. Distance presenting visual acuity was monocularly measured by using a logarithm of the minimum angle of resolution (logMAR) number chart at a distance of 4 m, with the participants wearing their "walk-in" optical corrections (spectacles or contact lenses), if any. Refraction was determined by subjective refraction by trained, certified study optometrists. Best corrected visual acuity was monocularly assessed and recorded in logMAR scores using the same test protocol as was used for presenting visual acuity. Undercorrected refractive error was defined as an improvement of at least 0.2 logMAR (2 lines equivalent) in the best corrected visual acuity compared with the presenting visual acuity in the better eye. The mean age of the subjects included in our study was 58 +/- 11 years, and 52% of the subjects were women. The prevalence rate of undercorrected refractive error among Singaporean Malay adults in our study (n = 3115) was 20.4% (age-standardized prevalence rate, 18.3%). More of the women had undercorrected refractive error than the men (21.8% vs. 18.8%, P = 0.04). Undercorrected refractive error was also more common in subjects older than 50 years than in subjects aged 40 to 49 years (22.6% vs. 14.3%, P Malay adults with refractive errors was higher than that of the Singaporean Chinese adults with refractive errors. Undercorrected refractive error is a significant cause of correctable visual impairment among Singaporean Malay adults, affecting one in five persons.

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.

Statistical errors in Monte Carlo estimates of systematic errors

Energy Technology Data Exchange (ETDEWEB)

Roe, Byron P. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)]. E-mail: byronroe@umich.edu

2007-01-01

For estimating the effects of a number of systematic errors on a data sample, one can generate Monte Carlo (MC) runs with systematic parameters varied and examine the change in the desired observed result. Two methods are often used. In the unisim method, the systematic parameters are varied one at a time by one standard deviation, each parameter corresponding to a MC run. In the multisim method (see ), each MC run has all of the parameters varied; the amount of variation is chosen from the expected distribution of each systematic parameter, usually assumed to be a normal distribution. The variance of the overall systematic error determination is derived for each of the two methods and comparisons are made between them. If one focuses not on the error in the prediction of an individual systematic error, but on the overall error due to all systematic errors in the error matrix element in data bin m, the number of events needed is strongly reduced because of the averaging effect over all of the errors. For simple models presented here the multisim model was far better if the statistical error in the MC samples was larger than an individual systematic error, while for the reverse case, the unisim model was better. Exact formulas and formulas for the simple toy models are presented so that realistic calculations can be made. The calculations in the present note are valid if the errors are in a linear region. If that region extends sufficiently far, one can have the unisims or multisims correspond to k standard deviations instead of one. This reduces the number of events required by a factor of k{sup 2}.

Statistical errors in Monte Carlo estimates of systematic errors

International Nuclear Information System (INIS)

Roe, Byron P.

2007-01-01

For estimating the effects of a number of systematic errors on a data sample, one can generate Monte Carlo (MC) runs with systematic parameters varied and examine the change in the desired observed result. Two methods are often used. In the unisim method, the systematic parameters are varied one at a time by one standard deviation, each parameter corresponding to a MC run. In the multisim method (see ), each MC run has all of the parameters varied; the amount of variation is chosen from the expected distribution of each systematic parameter, usually assumed to be a normal distribution. The variance of the overall systematic error determination is derived for each of the two methods and comparisons are made between them. If one focuses not on the error in the prediction of an individual systematic error, but on the overall error due to all systematic errors in the error matrix element in data bin m, the number of events needed is strongly reduced because of the averaging effect over all of the errors. For simple models presented here the multisim model was far better if the statistical error in the MC samples was larger than an individual systematic error, while for the reverse case, the unisim model was better. Exact formulas and formulas for the simple toy models are presented so that realistic calculations can be made. The calculations in the present note are valid if the errors are in a linear region. If that region extends sufficiently far, one can have the unisims or multisims correspond to k standard deviations instead of one. This reduces the number of events required by a factor of k 2

Magnetic Nanoparticle Thermometer: An Investigation of Minimum Error Transmission Path and AC Bias Error

Directory of Open Access Journals (Sweden)

Zhongzhou Du

2015-04-01

Full Text Available The signal transmission module of a magnetic nanoparticle thermometer (MNPT was established in this study to analyze the error sources introduced during the signal flow in the hardware system. The underlying error sources that significantly affected the precision of the MNPT were determined through mathematical modeling and simulation. A transfer module path with the minimum error in the hardware system was then proposed through the analysis of the variations of the system error caused by the significant error sources when the signal flew through the signal transmission module. In addition, a system parameter, named the signal-to-AC bias ratio (i.e., the ratio between the signal and AC bias, was identified as a direct determinant of the precision of the measured temperature. The temperature error was below 0.1 K when the signal-to-AC bias ratio was higher than 80 dB, and other system errors were not considered. The temperature error was below 0.1 K in the experiments with a commercial magnetic fluid (Sample SOR-10, Ocean Nanotechnology, Springdale, AR, USA when the hardware system of the MNPT was designed with the aforementioned method.

Predictors of Errors of Novice Java Programmers

Science.gov (United States)

Bringula, Rex P.; Manabat, Geecee Maybelline A.; Tolentino, Miguel Angelo A.; Torres, Edmon L.

2012-01-01

This descriptive study determined which of the sources of errors would predict the errors committed by novice Java programmers. Descriptive statistics revealed that the respondents perceived that they committed the identified eighteen errors infrequently. Thought error was perceived to be the main source of error during the laboratory programming…

Preventing Errors in Laterality

OpenAIRE

Landau, Elliot; Hirschorn, David; Koutras, Iakovos; Malek, Alexander; Demissie, Seleshie

2014-01-01

An error in laterality is the reporting of a finding that is present on the right side as on the left or vice versa. While different medical and surgical specialties have implemented protocols to help prevent such errors, very few studies have been published that describe these errors in radiology reports and ways to prevent them. We devised a system that allows the radiologist to view reports in a separate window, displayed in a simple font and with all terms of laterality highlighted in sep...

Field error lottery

Energy Technology Data Exchange (ETDEWEB)

Elliott, C.J.; McVey, B. (Los Alamos National Lab., NM (USA)); Quimby, D.C. (Spectra Technology, Inc., Bellevue, WA (USA))

1990-01-01

The level of field errors in an FEL is an important determinant of its performance. We have computed 3D performance of a large laser subsystem subjected to field errors of various types. These calculations have been guided by simple models such as SWOOP. The technique of choice is utilization of the FELEX free electron laser code that now possesses extensive engineering capabilities. Modeling includes the ability to establish tolerances of various types: fast and slow scale field bowing, field error level, beam position monitor error level, gap errors, defocusing errors, energy slew, displacement and pointing errors. Many effects of these errors on relative gain and relative power extraction are displayed and are the essential elements of determining an error budget. The random errors also depend on the particular random number seed used in the calculation. The simultaneous display of the performance versus error level of cases with multiple seeds illustrates the variations attributable to stochasticity of this model. All these errors are evaluated numerically for comprehensive engineering of the system. In particular, gap errors are found to place requirements beyond mechanical tolerances of {plus minus}25{mu}m, and amelioration of these may occur by a procedure utilizing direct measurement of the magnetic fields at assembly time. 4 refs., 12 figs.

Study of errors in absolute flux density measurements of Cassiopeia A

International Nuclear Information System (INIS)

Kanda, M.

1975-10-01

An error analysis for absolute flux density measurements of Cassiopeia A is discussed. The lower-bound quadrature-accumulation error for state-of-the-art measurements of the absolute flux density of Cas A around 7 GHz is estimated to be 1.71% for 3 sigma limits. The corresponding practicable error for the careful but not state-of-the-art measurement is estimated to be 4.46% for 3 sigma limits

Quantile Regression With Measurement Error

KAUST Repository

Wei, Ying

2009-08-27

Regression quantiles can be substantially biased when the covariates are measured with error. In this paper we propose a new method that produces consistent linear quantile estimation in the presence of covariate measurement error. The method corrects the measurement error induced bias by constructing joint estimating equations that simultaneously hold for all the quantile levels. An iterative EM-type estimation algorithm to obtain the solutions to such joint estimation equations is provided. The finite sample performance of the proposed method is investigated in a simulation study, and compared to the standard regression calibration approach. Finally, we apply our methodology to part of the National Collaborative Perinatal Project growth data, a longitudinal study with an unusual measurement error structure. © 2009 American Statistical Association.

Errors in clinical laboratories or errors in laboratory medicine?

Science.gov (United States)

Plebani, Mario

2006-01-01

Laboratory testing is a highly complex process and, although laboratory services are relatively safe, they are not as safe as they could or should be. Clinical laboratories have long focused their attention on quality control methods and quality assessment programs dealing with analytical aspects of testing. However, a growing body of evidence accumulated in recent decades demonstrates that quality in clinical laboratories cannot be assured by merely focusing on purely analytical aspects. The more recent surveys on errors in laboratory medicine conclude that in the delivery of laboratory testing, mistakes occur more frequently before (pre-analytical) and after (post-analytical) the test has been performed. Most errors are due to pre-analytical factors (46-68.2% of total errors), while a high error rate (18.5-47% of total errors) has also been found in the post-analytical phase. Errors due to analytical problems have been significantly reduced over time, but there is evidence that, particularly for immunoassays, interference may have a serious impact on patients. A description of the most frequent and risky pre-, intra- and post-analytical errors and advice on practical steps for measuring and reducing the risk of errors is therefore given in the present paper. Many mistakes in the Total Testing Process are called "laboratory errors", although these may be due to poor communication, action taken by others involved in the testing process (e.g., physicians, nurses and phlebotomists), or poorly designed processes, all of which are beyond the laboratory's control. Likewise, there is evidence that laboratory information is only partially utilized. A recent document from the International Organization for Standardization (ISO) recommends a new, broader definition of the term "laboratory error" and a classification of errors according to different criteria. In a modern approach to total quality, centered on patients' needs and satisfaction, the risk of errors and mistakes

Laboratory errors and patient safety.

Science.gov (United States)

Miligy, Dawlat A

2015-01-01

Laboratory data are extensively used in medical practice; consequently, laboratory errors have a tremendous impact on patient safety. Therefore, programs designed to identify and reduce laboratory errors, as well as, setting specific strategies are required to minimize these errors and improve patient safety. The purpose of this paper is to identify part of the commonly encountered laboratory errors throughout our practice in laboratory work, their hazards on patient health care and some measures and recommendations to minimize or to eliminate these errors. Recording the encountered laboratory errors during May 2008 and their statistical evaluation (using simple percent distribution) have been done in the department of laboratory of one of the private hospitals in Egypt. Errors have been classified according to the laboratory phases and according to their implication on patient health. Data obtained out of 1,600 testing procedure revealed that the total number of encountered errors is 14 tests (0.87 percent of total testing procedures). Most of the encountered errors lay in the pre- and post-analytic phases of testing cycle (representing 35.7 and 50 percent, respectively, of total errors). While the number of test errors encountered in the analytic phase represented only 14.3 percent of total errors. About 85.7 percent of total errors were of non-significant implication on patients health being detected before test reports have been submitted to the patients. On the other hand, the number of test errors that have been already submitted to patients and reach the physician represented 14.3 percent of total errors. Only 7.1 percent of the errors could have an impact on patient diagnosis. The findings of this study were concomitant with those published from the USA and other countries. This proves that laboratory problems are universal and need general standardization and bench marking measures. Original being the first data published from Arabic countries that

Repeated speech errors: evidence for learning.

Science.gov (United States)

Humphreys, Karin R; Menzies, Heather; Lake, Johanna K

2010-11-01

Three experiments elicited phonological speech errors using the SLIP procedure to investigate whether there is a tendency for speech errors on specific words to reoccur, and whether this effect can be attributed to implicit learning of an incorrect mapping from lemma to phonology for that word. In Experiment 1, when speakers made a phonological speech error in the study phase of the experiment (e.g. saying "beg pet" in place of "peg bet") they were over four times as likely to make an error on that same item several minutes later at test. A pseudo-error condition demonstrated that the effect is not simply due to a propensity for speakers to repeat phonological forms, regardless of whether or not they have been made in error. That is, saying "beg pet" correctly at study did not induce speakers to say "beg pet" in error instead of "peg bet" at test. Instead, the effect appeared to be due to learning of the error pathway. Experiment 2 replicated this finding, but also showed that after 48 h, errors made at study were no longer more likely to reoccur. As well as providing constraints on the longevity of the effect, this provides strong evidence that the error reoccurrences observed are not due to item-specific difficulty that leads individual speakers to make habitual mistakes on certain items. Experiment 3 showed that the diminishment of the effect 48 h later is not due to specific extra practice at the task. We discuss how these results fit in with a larger view of language as a dynamic system that is constantly adapting in response to experience. Copyright © 2010 Elsevier B.V. All rights reserved.

ERF/ERFC, Calculation of Error Function, Complementary Error Function, Probability Integrals

International Nuclear Information System (INIS)

Vogel, J.E.

1983-01-01

1 - Description of problem or function: ERF and ERFC are used to compute values of the error function and complementary error function for any real number. They may be used to compute other related functions such as the normal probability integrals. 4. Method of solution: The error function and complementary error function are approximated by rational functions. Three such rational approximations are used depending on whether - x .GE.4.0. In the first region the error function is computed directly and the complementary error function is computed via the identity erfc(x)=1.0-erf(x). In the other two regions the complementary error function is computed directly and the error function is computed from the identity erf(x)=1.0-erfc(x). The error function and complementary error function are real-valued functions of any real argument. The range of the error function is (-1,1). The range of the complementary error function is (0,2). 5. Restrictions on the complexity of the problem: The user is cautioned against using ERF to compute the complementary error function by using the identity erfc(x)=1.0-erf(x). This subtraction may cause partial or total loss of significance for certain values of x

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.

A methodology for translating positional error into measures of attribute error, and combining the two error sources

Science.gov (United States)

Yohay Carmel; Curtis Flather; Denis Dean

2006-01-01

This paper summarizes our efforts to investigate the nature, behavior, and implications of positional error and attribute error in spatiotemporal datasets. Estimating the combined influence of these errors on map analysis has been hindered by the fact that these two error types are traditionally expressed in different units (distance units, and categorical units,...

Wind Power Forecasting Error Frequency Analyses for Operational Power System Studies: Preprint

Energy Technology Data Exchange (ETDEWEB)

Florita, A.; Hodge, B. M.; Milligan, M.

2012-08-01

The examination of wind power forecasting errors is crucial for optimal unit commitment and economic dispatch of power systems with significant wind power penetrations. This scheduling process includes both renewable and nonrenewable generators, and the incorporation of wind power forecasts will become increasingly important as wind fleets constitute a larger portion of generation portfolios. This research considers the Western Wind and Solar Integration Study database of wind power forecasts and numerical actualizations. This database comprises more than 30,000 locations spread over the western United States, with a total wind power capacity of 960 GW. Error analyses for individual sites and for specific balancing areas are performed using the database, quantifying the fit to theoretical distributions through goodness-of-fit metrics. Insights into wind-power forecasting error distributions are established for various levels of temporal and spatial resolution, contrasts made among the frequency distribution alternatives, and recommendations put forth for harnessing the results. Empirical data are used to produce more realistic site-level forecasts than previously employed, such that higher resolution operational studies are possible. This research feeds into a larger work of renewable integration through the links wind power forecasting has with various operational issues, such as stochastic unit commitment and flexible reserve level determination.

An overview of intravenous-related medication administration errors as reported to MEDMARX, a national medication error-reporting program.

Science.gov (United States)

Hicks, Rodney W; Becker, Shawn C

2006-01-01

Medication errors can be harmful, especially if they involve the intravenous (IV) route of administration. A mixed-methodology study using a 5-year review of 73,769 IV-related medication errors from a national medication error reporting program indicates that between 3% and 5% of these errors were harmful. The leading type of error was omission, and the leading cause of error involved clinician performance deficit. Using content analysis, three themes-product shortage, calculation errors, and tubing interconnectivity-emerge and appear to predispose patients to harm. Nurses often participate in IV therapy, and these findings have implications for practice and patient safety. Voluntary medication error-reporting programs afford an opportunity to improve patient care and to further understanding about the nature of IV-related medication errors.

An Analysis of Errors Committed by Saudi Non-English Major Students in the English Paragraph Writing: A Study of Comparisons

Directory of Open Access Journals (Sweden)

Mohammed Nuruzzaman

2018-01-01

Full Text Available The present study investigates the writing errors of ninety Saudi non-English major undergraduate students of different proficiency levels from three faculties, who studied English as a foundation course at the English Language Center in the College of Languages &Translation at King Khalid University, Saudi Arabia in the academic year 2016-17. The findings reveal that the common errors the Saudi EFL students make in writing English paragraphs fall under four categories namely grammar, lexis, semantics and mechanics. Then it compares the categories, types and frequency of errors committed by these three groups of students. Among these categories, grammar has been observed as the most error-prone area where students commit errors the most. The study also posits that among the three groups, the students of the College of Medicine make the minimum errors in all the types and the highest number of errors is committed by the students of Engineering College. The College of Computer Science is in the second position in making errors. The frequency of error types is also found different among these three groups.

Valuing Errors for Learning: Espouse or Enact?

Science.gov (United States)

Grohnert, Therese; Meuwissen, Roger H. G.; Gijselaers, Wim H.

2017-01-01

Purpose: This study aims to investigate how organisations can discourage covering up and instead encourage learning from errors through a supportive learning from error climate. In explaining professionals' learning from error behaviour, this study distinguishes between espoused (verbally expressed) and enacted (behaviourally expressed) values…

A simulation study on the variation of virtual NMR signals by winding, bobbin, spacer error of HTS magnet

Energy Technology Data Exchange (ETDEWEB)

Kim, Jun Seong; Lee, Woo Seung; Kim, Jin Sub; Song, Seung Hyun; Nam, Seok Ho; Jeon, Hae Ryong; Beak, Geon Woo; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

2016-09-15

Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

Statistical errors in Monte Carlo estimates of systematic errors

Science.gov (United States)

Roe, Byron P.

2007-01-01

For estimating the effects of a number of systematic errors on a data sample, one can generate Monte Carlo (MC) runs with systematic parameters varied and examine the change in the desired observed result. Two methods are often used. In the unisim method, the systematic parameters are varied one at a time by one standard deviation, each parameter corresponding to a MC run. In the multisim method (see ), each MC run has all of the parameters varied; the amount of variation is chosen from the expected distribution of each systematic parameter, usually assumed to be a normal distribution. The variance of the overall systematic error determination is derived for each of the two methods and comparisons are made between them. If one focuses not on the error in the prediction of an individual systematic error, but on the overall error due to all systematic errors in the error matrix element in data bin m, the number of events needed is strongly reduced because of the averaging effect over all of the errors. For simple models presented here the multisim model was far better if the statistical error in the MC samples was larger than an individual systematic error, while for the reverse case, the unisim model was better. Exact formulas and formulas for the simple toy models are presented so that realistic calculations can be made. The calculations in the present note are valid if the errors are in a linear region. If that region extends sufficiently far, one can have the unisims or multisims correspond to k standard deviations instead of one. This reduces the number of events required by a factor of k2. The specific terms unisim and multisim were coined by Peter Meyers and Steve Brice, respectively, for the MiniBooNE experiment. However, the concepts have been developed over time and have been in general use for some time.

Comparison between calorimeter and HLNC errors

International Nuclear Information System (INIS)

Goldman, A.S.; De Ridder, P.; Laszlo, G.

1991-01-01

This paper summarizes an error analysis that compares systematic and random errors of total plutonium mass estimated for high-level neutron coincidence counter (HLNC) and calorimeter measurements. This task was part of an International Atomic Energy Agency (IAEA) study on the comparison of the two instruments to determine if HLNC measurement errors met IAEA standards and if the calorimeter gave ''significantly'' better precision. Our analysis was based on propagation of error models that contained all known sources of errors including uncertainties associated with plutonium isotopic measurements. 5 refs., 2 tabs

Comparing Absolute Error with Squared Error for Evaluating Empirical Models of Continuous Variables: Compositions, Implications, and Consequences

Science.gov (United States)

Gao, J.

2014-12-01

Reducing modeling error is often a major concern of empirical geophysical models. However, modeling errors can be defined in different ways: When the response variable is continuous, the most commonly used metrics are squared (SQ) and absolute (ABS) errors. For most applications, ABS error is the more natural, but SQ error is mathematically more tractable, so is often used as a substitute with little scientific justification. Existing literature has not thoroughly investigated the implications of using SQ error in place of ABS error, especially not geospatially. This study compares the two metrics through the lens of bias-variance decomposition (BVD). BVD breaks down the expected modeling error of each model evaluation point into bias (systematic error), variance (model sensitivity), and noise (observation instability). It offers a way to probe the composition of various error metrics. I analytically derived the BVD of ABS error and compared it with the well-known SQ error BVD, and found that not only the two metrics measure the characteristics of the probability distributions of modeling errors differently, but also the effects of these characteristics on the overall expected error are different. Most notably, under SQ error all bias, variance, and noise increase expected error, while under ABS error certain parts of the error components reduce expected error. Since manipulating these subtractive terms is a legitimate way to reduce expected modeling error, SQ error can never capture the complete story embedded in ABS error. I then empirically compared the two metrics with a supervised remote sensing model for mapping surface imperviousness. Pair-wise spatially-explicit comparison for each error component showed that SQ error overstates all error components in comparison to ABS error, especially variance-related terms. Hence, substituting ABS error with SQ error makes model performance appear worse than it actually is, and the analyst would more likely accept a

Organizational Climate, Stress, and Error in Primary Care: The MEMO Study

National Research Council Canada - National Science Library

Linzer, Mark; Manwell, Linda B; Mundt, Marlon; Williams, Eric; Maguire, Ann; McMurray, Julia; Plane, Mary B

2005-01-01

.... Physician surveys assessed office environment and organizational climate (OC). Stress was measured using a 4-item scale, past errors were self reported, and the likelihood of future errors was self-assessed using the OSPRE...

Measuring the relationship between interruptions, multitasking and prescribing errors in an emergency department: a study protocol.

Science.gov (United States)

Raban, Magdalena Z; Walter, Scott R; Douglas, Heather E; Strumpman, Dana; Mackenzie, John; Westbrook, Johanna I

2015-10-13

Interruptions and multitasking are frequent in clinical settings, and have been shown in the cognitive psychology literature to affect performance, increasing the risk of error. However, comparatively less is known about their impact on errors in clinical work. This study will assess the relationship between prescribing errors, interruptions and multitasking in an emergency department (ED) using direct observations and chart review. The study will be conducted in an ED of a 440-bed teaching hospital in Sydney, Australia. Doctors will be shadowed at proximity by observers for 2 h time intervals while they are working on day shift (between 0800 and 1800). Time stamped data on tasks, interruptions and multitasking will be recorded on a handheld computer using the validated Work Observation Method by Activity Timing (WOMBAT) tool. The prompts leading to interruptions and multitasking will also be recorded. When doctors prescribe medication, type of chart and chart sections written on, along with the patient's medical record number (MRN) will be recorded. A clinical pharmacist will access patient records and assess the medication orders for prescribing errors. The prescribing error rate will be calculated per prescribing task and is defined as the number of errors divided by the number of medication orders written during the prescribing task. The association between prescribing error rates, and rates of prompts, interruptions and multitasking will be assessed using statistical modelling. Ethics approval has been obtained from the hospital research ethics committee. Eligible doctors will be provided with written information sheets and written consent will be obtained if they agree to participate. Doctor details and MRNs will be kept separate from the data on prescribing errors, and will not appear in the final data set for analysis. Study results will be disseminated in publications and feedback to the ED. Published by the BMJ Publishing Group Limited. For permission

The impact of a closed-loop electronic prescribing and administration system on prescribing errors, administration errors and staff time: a before-and-after study.

Science.gov (United States)

Franklin, Bryony Dean; O'Grady, Kara; Donyai, Parastou; Jacklin, Ann; Barber, Nick

2007-08-01

To assess the impact of a closed-loop electronic prescribing, automated dispensing, barcode patient identification and electronic medication administration record (EMAR) system on prescribing and administration errors, confirmation of patient identity before administration, and staff time. Before-and-after study in a surgical ward of a teaching hospital, involving patients and staff of that ward. Closed-loop electronic prescribing, automated dispensing, barcode patient identification and EMAR system. Percentage of new medication orders with a prescribing error, percentage of doses with medication administration errors (MAEs) and percentage given without checking patient identity. Time spent prescribing and providing a ward pharmacy service. Nursing time on medication tasks. Prescribing errors were identified in 3.8% of 2450 medication orders pre-intervention and 2.0% of 2353 orders afterwards (pMedical staff required 15 s to prescribe a regular inpatient drug pre-intervention and 39 s afterwards (p = 0.03; t test). Time spent providing a ward pharmacy service increased from 68 min to 98 min each weekday (p = 0.001; t test); 22% of drug charts were unavailable pre-intervention. Time per drug administration round decreased from 50 min to 40 min (p = 0.006; t test); nursing time on medication tasks outside of drug rounds increased from 21.1% to 28.7% (p = 0.006; chi(2) test). A closed-loop electronic prescribing, dispensing and barcode patient identification system reduced prescribing errors and MAEs, and increased confirmation of patient identity before administration. Time spent on medication-related tasks increased.

Modeling and Experimental Study of Soft Error Propagation Based on Cellular Automaton

Directory of Open Access Journals (Sweden)

Wei He

2016-01-01

Full Text Available Aiming to estimate SEE soft error performance of complex electronic systems, a soft error propagation model based on cellular automaton is proposed and an estimation methodology based on circuit partitioning and error propagation is presented. Simulations indicate that different fault grade jamming and different coupling factors between cells are the main parameters influencing the vulnerability of the system. Accelerated radiation experiments have been developed to determine the main parameters for raw soft error vulnerability of the module and coupling factors. Results indicate that the proposed method is feasible.

Medication Errors - A Review

OpenAIRE

Vinay BC; Nikhitha MK; Patel Sunil B

2015-01-01

In this present review article, regarding medication errors its definition, medication error problem, types of medication errors, common causes of medication errors, monitoring medication errors, consequences of medication errors, prevention of medication error and managing medication errors have been explained neatly and legibly with proper tables which is easy to understand.

Economic impact of medication error: a systematic review.

Science.gov (United States)

Walsh, Elaine K; Hansen, Christina Raae; Sahm, Laura J; Kearney, Patricia M; Doherty, Edel; Bradley, Colin P

2017-05-01

Medication error is a significant source of morbidity and mortality among patients. Clinical and cost-effectiveness evidence are required for the implementation of quality of care interventions. Reduction of error-related cost is a key potential benefit of interventions addressing medication error. The aim of this review was to describe and quantify the economic burden associated with medication error. PubMed, Cochrane, Embase, CINAHL, EconLit, ABI/INFORM, Business Source Complete were searched. Studies published 2004-2016 assessing the economic impact of medication error were included. Cost values were expressed in Euro 2015. A narrative synthesis was performed. A total of 4572 articles were identified from database searching, and 16 were included in the review. One study met all applicable quality criteria. Fifteen studies expressed economic impact in monetary terms. Mean cost per error per study ranged from €2.58 to €111 727.08. Healthcare costs were used to measure economic impact in 15 of the included studies with one study measuring litigation costs. Four studies included costs incurred in primary care with the remaining 12 measuring hospital costs. Five studies looked at general medication error in a general population with 11 studies reporting the economic impact of an individual type of medication error or error within a specific patient population. Considerable variability existed between studies in terms of financial cost, patients, settings and errors included. Many were of poor quality. Assessment of economic impact was conducted predominantly in the hospital setting with little assessment of primary care impact. Limited parameters were used to establish economic impact. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Error Patterns

NARCIS (Netherlands)

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,

Average beta-beating from random errors

CERN Document Server

Tomas Garcia, Rogelio; Langner, Andy Sven; Malina, Lukas; Franchi, Andrea; CERN. Geneva. ATS Department

2018-01-01

The impact of random errors on average β-beating is studied via analytical derivations and simulations. A systematic positive β-beating is expected from random errors quadratic with the sources or, equivalently, with the rms β-beating. However, random errors do not have a systematic effect on the tune.

Learning from Errors: Effects of Teachers Training on Students' Attitudes towards and Their Individual Use of Errors

Science.gov (United States)

Rach, Stefanie; Ufer, Stefan; Heinze, Aiso

2013-01-01

Constructive error handling is considered an important factor for individual learning processes. In a quasi-experimental study with Grades 6 to 9 students, we investigate effects on students' attitudes towards errors as learning opportunities in two conditions: an error-tolerant classroom culture, and the first condition along with additional…

Quantification of human errors in level-1 PSA studies in NUPEC/JINS

International Nuclear Information System (INIS)

Hirano, M.; Hirose, M.; Sugawara, M.; Hashiba, T.

1991-01-01

THERP (Technique for Human Error Rate Prediction) method is mainly adopted to evaluate the pre-accident and post-accident human error rates. Performance shaping factors are derived by taking Japanese operational practice into account. Several examples of human error rates with calculational procedures are presented. The important human interventions of typical Japanese NPPs are also presented. (orig./HP)

The error in total error reduction.

Science.gov (United States)

Witnauer, James E; Urcelay, Gonzalo P; Miller, Ralph R

2014-02-01

Most models of human and animal learning assume that learning is proportional to the discrepancy between a delivered outcome and the outcome predicted by all cues present during that trial (i.e., total error across a stimulus compound). This total error reduction (TER) view has been implemented in connectionist and artificial neural network models to describe the conditions under which weights between units change. Electrophysiological work has revealed that the activity of dopamine neurons is correlated with the total error signal in models of reward learning. Similar neural mechanisms presumably support fear conditioning, human contingency learning, and other types of learning. Using a computational modeling approach, we compared several TER models of associative learning to an alternative model that rejects the TER assumption in favor of local error reduction (LER), which assumes that learning about each cue is proportional to the discrepancy between the delivered outcome and the outcome predicted by that specific cue on that trial. The LER model provided a better fit to the reviewed data than the TER models. Given the superiority of the LER model with the present data sets, acceptance of TER should be tempered. Copyright © 2013 Elsevier Inc. All rights reserved.

Investigating Medication Errors in Educational Health Centers of Kermanshah

Directory of Open Access Journals (Sweden)

Mohsen Mohammadi

2015-08-01

Full Text Available Background and objectives : Medication errors can be a threat to the safety of patients. Preventing medication errors requires reporting and investigating such errors. The present study was conducted with the purpose of investigating medication errors in educational health centers of Kermanshah. Material and Methods: The present research is an applied, descriptive-analytical study and is done as a survey. Error Report of Ministry of Health and Medical Education was used for data collection. The population of the study included all the personnel (nurses, doctors, paramedics of educational health centers of Kermanshah. Among them, those who reported the committed errors were selected as the sample of the study. The data analysis was done using descriptive statistics and Chi 2 Test using SPSS version 18. Results: The findings of the study showed that most errors were related to not using medication properly, the least number of errors were related to improper dose, and the majority of errors occurred in the morning. The most frequent reason for errors was staff negligence and the least frequent was the lack of knowledge. Conclusion: The health care system should create an environment for detecting and reporting errors by the personnel, recognizing related factors causing errors, training the personnel and create a good working environment and standard workload.

Haplotype reconstruction error as a classical misclassification problem: introducing sensitivity and specificity as error measures.

Directory of Open Access Journals (Sweden)

Claudia Lamina

Full Text Available BACKGROUND: Statistically reconstructing haplotypes from single nucleotide polymorphism (SNP genotypes, can lead to falsely classified haplotypes. This can be an issue when interpreting haplotype association results or when selecting subjects with certain haplotypes for subsequent functional studies. It was our aim to quantify haplotype reconstruction error and to provide tools for it. METHODS AND RESULTS: By numerous simulation scenarios, we systematically investigated several error measures, including discrepancy, error rate, and R(2, and introduced the sensitivity and specificity to this context. We exemplified several measures in the KORA study, a large population-based study from Southern Germany. We find that the specificity is slightly reduced only for common haplotypes, while the sensitivity was decreased for some, but not all rare haplotypes. The overall error rate was generally increasing with increasing number of loci, increasing minor allele frequency of SNPs, decreasing correlation between the alleles and increasing ambiguity. CONCLUSIONS: We conclude that, with the analytical approach presented here, haplotype-specific error measures can be computed to gain insight into the haplotype uncertainty. This method provides the information, if a specific risk haplotype can be expected to be reconstructed with rather no or high misclassification and thus on the magnitude of expected bias in association estimates. We also illustrate that sensitivity and specificity separate two dimensions of the haplotype reconstruction error, which completely describe the misclassification matrix and thus provide the prerequisite for methods accounting for misclassification.

Impact of Stewardship Interventions on Antiretroviral Medication Errors in an Urban Medical Center: A 3-Year, Multiphase Study.

Science.gov (United States)

Zucker, Jason; Mittal, Jaimie; Jen, Shin-Pung; Cheng, Lucy; Cennimo, David

2016-03-01

There is a high prevalence of HIV infection in Newark, New Jersey, with University Hospital admitting approximately 600 HIV-infected patients per year. Medication errors involving antiretroviral therapy (ART) could significantly affect treatment outcomes. The goal of this study was to evaluate the effectiveness of various stewardship interventions in reducing the prevalence of prescribing errors involving ART. This was a retrospective review of all inpatients receiving ART for HIV treatment during three distinct 6-month intervals over a 3-year period. During the first year, the baseline prevalence of medication errors was determined. During the second year, physician and pharmacist education was provided, and a computerized order entry system with drug information resources and prescribing recommendations was implemented. Prospective audit of ART orders with feedback was conducted in the third year. Analyses and comparisons were made across the three phases of this study. Of the 334 patients with HIV admitted in the first year, 45% had at least one antiretroviral medication error and 38% had uncorrected errors at the time of discharge. After education and computerized order entry, significant reductions in medication error rates were observed compared to baseline rates; 36% of 315 admissions had at least one error and 31% had uncorrected errors at discharge. While the prevalence of antiretroviral errors in year 3 was similar to that of year 2 (37% of 276 admissions), there was a significant decrease in the prevalence of uncorrected errors at discharge (12%) with the use of prospective review and intervention. Interventions, such as education and guideline development, can aid in reducing ART medication errors, but a committed stewardship program is necessary to elicit the greatest impact. © 2016 Pharmacotherapy Publications, Inc.

Errorful and errorless learning: The impact of cue-target constraint in learning from errors.

Science.gov (United States)

Bridger, Emma K; Mecklinger, Axel

2014-08-01

The benefits of testing on learning are well described, and attention has recently turned to what happens when errors are elicited during learning: Is testing nonetheless beneficial, or can errors hinder learning? Whilst recent findings have indicated that tests boost learning even if errors are made on every trial, other reports, emphasizing the benefits of errorless learning, have indicated that errors lead to poorer later memory performance. The possibility that this discrepancy is a function of the materials that must be learned-in particular, the relationship between the cues and targets-was addressed here. Cued recall after either a study-only errorless condition or an errorful learning condition was contrasted across cue-target associations, for which the extent to which the target was constrained by the cue was either high or low. Experiment 1 showed that whereas errorful learning led to greater recall for low-constraint stimuli, it led to a significant decrease in recall for high-constraint stimuli. This interaction is thought to reflect the extent to which retrieval is constrained by the cue-target association, as well as by the presence of preexisting semantic associations. The advantage of errorful retrieval for low-constraint stimuli was replicated in Experiment 2, and the interaction with stimulus type was replicated in Experiment 3, even when guesses were randomly designated as being either correct or incorrect. This pattern provides support for inferences derived from reports in which participants made errors on all learning trials, whilst highlighting the impact of material characteristics on the benefits and disadvantages that accrue from errorful learning in episodic memory.

Error management process for power stations

International Nuclear Information System (INIS)

Hirotsu, Yuko; Takeda, Daisuke; Fujimoto, Junzo; Nagasaka, Akihiko

2016-01-01

The purpose of this study is to establish 'error management process for power stations' for systematizing activities for human error prevention and for festering continuous improvement of these activities. The following are proposed by deriving concepts concerning error management process from existing knowledge and realizing them through application and evaluation of their effectiveness at a power station: an entire picture of error management process that facilitate four functions requisite for maraging human error prevention effectively (1. systematizing human error prevention tools, 2. identifying problems based on incident reports and taking corrective actions, 3. identifying good practices and potential problems for taking proactive measures, 4. prioritizeng human error prevention tools based on identified problems); detail steps for each activity (i.e. developing an annual plan for human error prevention, reporting and analyzing incidents and near misses) based on a model of human error causation; procedures and example of items for identifying gaps between current and desired levels of executions and outputs of each activity; stages for introducing and establishing the above proposed error management process into a power station. By giving shape to above proposals at a power station, systematization and continuous improvement of activities for human error prevention in line with the actual situation of the power station can be expected. (author)

[Medication errors in a hospital emergency department: study of the current situation and critical points for improving patient safety].

Science.gov (United States)

Pérez-Díez, Cristina; Real-Campaña, José Manuel; Noya-Castro, María Carmen; Andrés-Paricio, Felicidad; Reyes Abad-Sazatornil, María; Bienvenido Povar-Marco, Javier

2017-01-01

To determine the frequency of medication errors and incident types in a tertiary-care hospital emergency department. To quantify and classify medication errors and identify critical points where measures should be implemented to improve patient safety. Prospective direct-observation study to detect errors made in June and July 2016. The overall error rate was 23.7%. The most common errors were made while medications were administered (10.9%). We detected 1532 incidents: 53.6% on workdays (P=.001), 43.1% during the afternoon/evening shift (P=.004), and 43.1% in observation areas (P=.004). The medication error rate was significant. Most errors and incidents occurred during the afternoon/evening shift and in the observation area. Most errors were related to administration of medications.

Learning from Errors at Work: A Replication Study in Elder Care Nursing

Science.gov (United States)

Leicher, Veronika; Mulder, Regina H.; Bauer, Johannes

2013-01-01

Learning from errors is an important way of learning at work. In this article, we analyse conditions under which elder care nurses use errors as a starting point for the engagement in social learning activities (ESLA) in the form of joint reflection with colleagues on potential causes of errors and ways to prevent them in future. The goal of our…

Error characterization for asynchronous computations: Proxy equation approach

Science.gov (United States)

Sallai, Gabriella; Mittal, Ankita; Girimaji, Sharath

2017-11-01

Numerical techniques for asynchronous fluid flow simulations are currently under development to enable efficient utilization of massively parallel computers. These numerical approaches attempt to accurately solve time evolution of transport equations using spatial information at different time levels. The truncation error of asynchronous methods can be divided into two parts: delay dependent (EA) or asynchronous error and delay independent (ES) or synchronous error. The focus of this study is a specific asynchronous error mitigation technique called proxy-equation approach. The aim of this study is to examine these errors as a function of the characteristic wavelength of the solution. Mitigation of asynchronous effects requires that the asynchronous error be smaller than synchronous truncation error. For a simple convection-diffusion equation, proxy-equation error analysis identifies critical initial wave-number, λc. At smaller wave numbers, synchronous error are larger than asynchronous errors. We examine various approaches to increase the value of λc in order to improve the range of applicability of proxy-equation approach.

Friendship at work and error disclosure

Directory of Open Access Journals (Sweden)

Hsiao-Yen Mao

2017-10-01

Full Text Available Organizations rely on contextual factors to promote employee disclosure of self-made errors, which induces a resource dilemma (i.e., disclosure entails costing one's own resources to bring others resources and a friendship dilemma (i.e., disclosure is seemingly easier through friendship, yet the cost of friendship is embedded. This study proposes that friendship at work enhances error disclosure and uses conservation of resources theory as underlying explanation. A three-wave survey collected data from 274 full-time employees with a variety of occupational backgrounds. Empirical results indicated that friendship enhanced error disclosure partially through relational mechanisms of employees’ attitudes toward coworkers (i.e., employee engagement and of coworkers’ attitudes toward employees (i.e., perceived social worth. Such effects hold when controlling for established predictors of error disclosure. This study expands extant perspectives on employee error and the theoretical lenses used to explain the influence of friendship at work. We propose that, while promoting error disclosure through both contextual and relational approaches, organizations should be vigilant about potential incongruence.

Positive Beliefs about Errors as an Important Element of Adaptive Individual Dealing with Errors during Academic Learning

Science.gov (United States)

Tulis, Maria; Steuer, Gabriele; Dresel, Markus

2018-01-01

Research on learning from errors gives reason to assume that errors provide a high potential to facilitate deep learning if students are willing and able to take these learning opportunities. The first aim of this study was to analyse whether beliefs about errors as learning opportunities can be theoretically and empirically distinguished from…

Organizational Climate, Stress, and Error in Primary Care: The MEMO Study

Science.gov (United States)

2005-05-01

quality, and errors. This model was derived from our earlier work, the Physician Worklife Study14,15 as well as the pioneering work of Lazarus and... Worklife Study instrument,14, 15 and included our five-item global job satisfaction measure and a newly implemented four-item job stress measure.21...measures of practice emphasis with respect to issues such as work–home balance , professionalism, and diversity in office staff, as well as single

Correcting for multivariate measurement error by regression calibration in meta-analyses of epidemiological studies

DEFF Research Database (Denmark)

Tybjærg-Hansen, Anne

2009-01-01

Within-person variability in measured values of multiple risk factors can bias their associations with disease. The multivariate regression calibration (RC) approach can correct for such measurement error and has been applied to studies in which true values or independent repeat measurements...... of the risk factors are observed on a subsample. We extend the multivariate RC techniques to a meta-analysis framework where multiple studies provide independent repeat measurements and information on disease outcome. We consider the cases where some or all studies have repeat measurements, and compare study......-specific, averaged and empirical Bayes estimates of RC parameters. Additionally, we allow for binary covariates (e.g. smoking status) and for uncertainty and time trends in the measurement error corrections. Our methods are illustrated using a subset of individual participant data from prospective long-term studies...

Study of Error Propagation in the Transformations of Dynamic Thermal Models of Buildings

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Loïc Raillon

2017-01-01

Full Text Available Dynamic behaviour of a system may be described by models with different forms: thermal (RC networks, state-space representations, transfer functions, and ARX models. These models, which describe the same process, are used in the design, simulation, optimal predictive control, parameter identification, fault detection and diagnosis, and so on. Since more forms are available, it is interesting to know which one is the most suitable by estimating the sensitivity of the model to transform into a physical model, which is represented by a thermal network. A procedure for the study of error by Monte Carlo simulation and of factor prioritization is exemplified on a simple, but representative, thermal model of a building. The analysis of the propagation of errors and of the influence of the errors on the parameter estimation shows that the transformation from state-space representation to transfer function is more robust than the other way around. Therefore, if only one model is chosen, the state-space representation is preferable.

Prevalence of Refractive Error in Singaporean Chinese Children: The Strabismus, Amblyopia, and Refractive Error in Young Singaporean Children (STARS) Study

OpenAIRE

Dirani, Mohamed; Chan, Yiong-Huak; Gazzard, Gus; Hornbeak, Dana Marie; Leo, Seo-Wei; Selvaraj, Prabakaran; Zhou, Brendan; Young, Terri L.; Mitchell, Paul; Varma, Rohit; Wong, Tien Yin; Saw, Seang-Mei

2010-01-01

Using population-based data, the authors report, for the first time, the prevalence of refractive error in Singaporean Chinese children aged 6 to 72 months. In selected regions of Singapore, myopia has been shown to affect more than 80% of adults; therefore, this paper provides insights into the development of refractive error at a very young age.

Two-dimensional errors

International Nuclear Information System (INIS)

Anon.

1991-01-01

This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

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

Science.gov (United States)

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

2016-08-24

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

Analysis of errors in forensic science

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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.

Modeling and Experimental Study of Soft Error Propagation Based on Cellular Automaton

OpenAIRE

He, Wei; Wang, Yueke; Xing, Kefei; Yang, Jianwei

2016-01-01

Aiming to estimate SEE soft error performance of complex electronic systems, a soft error propagation model based on cellular automaton is proposed and an estimation methodology based on circuit partitioning and error propagation is presented. Simulations indicate that different fault grade jamming and different coupling factors between cells are the main parameters influencing the vulnerability of the system. Accelerated radiation experiments have been developed to determine the main paramet...

Perceptions and Attitudes towards Medication Error Reporting in Primary Care Clinics: A Qualitative Study in Malaysia.

Science.gov (United States)

Samsiah, A; Othman, Noordin; Jamshed, Shazia; Hassali, Mohamed Azmi

2016-01-01

To explore and understand participants' perceptions and attitudes towards the reporting of medication errors (MEs). A qualitative study using in-depth interviews of 31 healthcare practitioners from nine publicly funded, primary care clinics in three states in peninsular Malaysia was conducted for this study. The participants included family medicine specialists, doctors, pharmacists, pharmacist assistants, nurses and assistant medical officers. The interviews were audiotaped and transcribed verbatim. Analysis of the data was guided by the framework approach. Six themes and 28 codes were identified. Despite the availability of a reporting system, most of the participants agreed that MEs were underreported. The nature of the error plays an important role in determining the reporting. The reporting system, organisational factors, provider factors, reporter's burden and benefit of reporting also were identified. Healthcare practitioners in primary care clinics understood the importance of reporting MEs to improve patient safety. Their perceptions and attitudes towards reporting of MEs were influenced by many factors which affect the decision-making process of whether or not to report. Although the process is complex, it primarily is determined by the severity of the outcome of the errors. The participants voluntarily report the errors if they are familiar with the reporting system, what error to report, when to report and what form to use.

A vignette study to examine health care professionals' attitudes towards patient involvement in error prevention.

Science.gov (United States)

Schwappach, David L B; Frank, Olga; Davis, Rachel E

2013-10-01

Various authorities recommend the participation of patients in promoting patient safety, but little is known about health care professionals' (HCPs') attitudes towards patients' involvement in safety-related behaviours. To investigate how HCPs evaluate patients' behaviours and HCP responses to patient involvement in the behaviour, relative to different aspects of the patient, the involved HCP and the potential error. Cross-sectional fractional factorial survey with seven factors embedded in two error scenarios (missed hand hygiene, medication error). Each survey included two randomized vignettes that described the potential error, a patient's reaction to that error and the HCP response to the patient. Twelve hospitals in Switzerland. A total of 1141 HCPs (response rate 45%). Approval of patients' behaviour, HCP response to the patient, anticipated effects on the patient-HCP relationship, HCPs' support for being asked the question, affective response to the vignettes. Outcomes were measured on 7-point scales. Approval of patients' safety-related interventions was generally high and largely affected by patients' behaviour and correct identification of error. Anticipated effects on the patient-HCP relationship were much less positive, little correlated with approval of patients' behaviour and were mainly determined by the HCP response to intervening patients. HCPs expressed more favourable attitudes towards patients intervening about a medication error than about hand sanitation. This study provides the first insights into predictors of HCPs' attitudes towards patient engagement in safety. Future research is however required to assess the generalizability of the findings into practice before training can be designed to address critical issues. © 2012 John Wiley & Sons Ltd.

Correcting AUC for Measurement Error.

Science.gov (United States)

Rosner, Bernard; Tworoger, Shelley; Qiu, Weiliang

2015-12-01

Diagnostic biomarkers are used frequently in epidemiologic and clinical work. The ability of a diagnostic biomarker to discriminate between subjects who develop disease (cases) and subjects who do not (controls) is often measured by the area under the receiver operating characteristic curve (AUC). The diagnostic biomarkers are usually measured with error. Ignoring measurement error can cause biased estimation of AUC, which results in misleading interpretation of the efficacy of a diagnostic biomarker. Several methods have been proposed to correct AUC for measurement error, most of which required the normality assumption for the distributions of diagnostic biomarkers. In this article, we propose a new method to correct AUC for measurement error and derive approximate confidence limits for the corrected AUC. The proposed method does not require the normality assumption. Both real data analyses and simulation studies show good performance of the proposed measurement error correction method.

Errors in otology.

Science.gov (United States)

Kartush, J M

1996-11-01

Practicing medicine successfully requires that errors in diagnosis and treatment be minimized. Malpractice laws encourage litigators to ascribe all medical errors to incompetence and negligence. There are, however, many other causes of unintended outcomes. This article describes common causes of errors and suggests ways to minimize mistakes in otologic practice. Widespread dissemination of knowledge about common errors and their precursors can reduce the incidence of their occurrence. Consequently, laws should be passed to allow for a system of non-punitive, confidential reporting of errors and "near misses" that can be shared by physicians nationwide.

SPACE-BORNE LASER ALTIMETER GEOLOCATION ERROR ANALYSIS

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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.

Human errors in NPP operations

International Nuclear Information System (INIS)

Sheng Jufang

1993-01-01

Based on the operational experiences of nuclear power plants (NPPs), the importance of studying human performance problems is described. Statistical analysis on the significance or frequency of various root-causes and error-modes from a large number of human-error-related events demonstrate that the defects in operation/maintenance procedures, working place factors, communication and training practices are primary root-causes, while omission, transposition, quantitative mistake are the most frequent among the error-modes. Recommendations about domestic research on human performance problem in NPPs are suggested

The Impact of Error-Management Climate, Error Type and Error Originator on Auditors’ Reporting Errors Discovered on Audit Work Papers

NARCIS (Netherlands)

A.H. Gold-Nöteberg (Anna); U. Gronewold (Ulfert); S. Salterio (Steve)

2010-01-01

textabstractWe examine factors affecting the auditor’s willingness to report their own or their peers’ self-discovered errors in working papers subsequent to detailed working paper review. Prior research has shown that errors in working papers are detected in the review process; however, such

Learning from Errors

OpenAIRE

Martínez-Legaz, Juan Enrique; Soubeyran, Antoine

2003-01-01

We present a model of learning in which agents learn from errors. If an action turns out to be an error, the agent rejects not only that action but also neighboring actions. We find that, keeping memory of his errors, under mild assumptions an acceptable solution is asymptotically reached. Moreover, one can take advantage of big errors for a faster learning.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-06-15

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

Medication errors with the use of allopurinol and colchicine : A retrospective study of a national, anonymous Internet-accessible error reporting system

NARCIS (Netherlands)

Mikuls, TR; Curtis, [No Value; Allison, JJ; Hicks, RW; Saag, KG

Objectives. To more closely assess medication errors in gout care, we examined data from a national, Internet-accessible error reporting program over a 5-year reporting period. Methods. We examined data from the MEDMARX (TM) database, covering the period from January 1, 1999 through December 31,

Relating Complexity and Error Rates of Ontology Concepts. More Complex NCIt Concepts Have More Errors.

Science.gov (United States)

Min, Hua; Zheng, Ling; Perl, Yehoshua; Halper, Michael; De Coronado, Sherri; Ochs, Christopher

2017-05-18

Ontologies are knowledge structures that lend support to many health-information systems. A study is carried out to assess the quality of ontological concepts based on a measure of their complexity. The results show a relation between complexity of concepts and error rates of concepts. A measure of lateral complexity defined as the number of exhibited role types is used to distinguish between more complex and simpler concepts. Using a framework called an area taxonomy, a kind of abstraction network that summarizes the structural organization of an ontology, concepts are divided into two groups along these lines. Various concepts from each group are then subjected to a two-phase QA analysis to uncover and verify errors and inconsistencies in their modeling. A hierarchy of the National Cancer Institute thesaurus (NCIt) is used as our test-bed. A hypothesis pertaining to the expected error rates of the complex and simple concepts is tested. Our study was done on the NCIt's Biological Process hierarchy. Various errors, including missing roles, incorrect role targets, and incorrectly assigned roles, were discovered and verified in the two phases of our QA analysis. The overall findings confirmed our hypothesis by showing a statistically significant difference between the amounts of errors exhibited by more laterally complex concepts vis-à-vis simpler concepts. QA is an essential part of any ontology's maintenance regimen. In this paper, we reported on the results of a QA study targeting two groups of ontology concepts distinguished by their level of complexity, defined in terms of the number of exhibited role types. The study was carried out on a major component of an important ontology, the NCIt. The findings suggest that more complex concepts tend to have a higher error rate than simpler concepts. These findings can be utilized to guide ongoing efforts in ontology QA.

The impact of a closed‐loop electronic prescribing and administration system on prescribing errors, administration errors and staff time: a before‐and‐after study

Science.gov (United States)

Franklin, Bryony Dean; O'Grady, Kara; Donyai, Parastou; Jacklin, Ann; Barber, Nick

2007-01-01

Objectives To assess the impact of a closed‐loop electronic prescribing, automated dispensing, barcode patient identification and electronic medication administration record (EMAR) system on prescribing and administration errors, confirmation of patient identity before administration, and staff time. Design, setting and participants Before‐and‐after study in a surgical ward of a teaching hospital, involving patients and staff of that ward. Intervention Closed‐loop electronic prescribing, automated dispensing, barcode patient identification and EMAR system. Main outcome measures Percentage of new medication orders with a prescribing error, percentage of doses with medication administration errors (MAEs) and percentage given without checking patient identity. Time spent prescribing and providing a ward pharmacy service. Nursing time on medication tasks. Results Prescribing errors were identified in 3.8% of 2450 medication orders pre‐intervention and 2.0% of 2353 orders afterwards (pMedical staff required 15 s to prescribe a regular inpatient drug pre‐intervention and 39 s afterwards (p = 0.03; t test). Time spent providing a ward pharmacy service increased from 68 min to 98 min each weekday (p = 0.001; t test); 22% of drug charts were unavailable pre‐intervention. Time per drug administration round decreased from 50 min to 40 min (p = 0.006; t test); nursing time on medication tasks outside of drug rounds increased from 21.1% to 28.7% (p = 0.006; χ2 test). Conclusions A closed‐loop electronic prescribing, dispensing and barcode patient identification system reduced prescribing errors and MAEs, and increased confirmation of patient identity before administration. Time spent on medication‐related tasks increased. PMID:17693676

CORRECTING ERRORS: THE RELATIVE EFFICACY OF DIFFERENT FORMS OF ERROR FEEDBACK IN SECOND LANGUAGE WRITING

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Chitra Jayathilake

2013-01-01

Full Text Available Error correction in ESL (English as a Second Language classes has been a focal phenomenon in SLA (Second Language Acquisition research due to some controversial research results and diverse feedback practices. This paper presents a study which explored the relative efficacy of three forms of error correction employed in ESL writing classes: focusing on the acquisition of one grammar element both for immediate and delayed language contexts, and collecting data from university undergraduates, this study employed an experimental research design with a pretest-treatment-posttests structure. The research revealed that the degree of success in acquiring L2 (Second Language grammar through error correction differs according to the form of the correction and to learning contexts. While the findings are discussed in relation to the previous literature, this paper concludes creating a cline of error correction forms to be promoted in Sri Lankan L2 writing contexts, particularly in ESL contexts in Universities.

Collection of offshore human error probability data

International Nuclear Information System (INIS)

Basra, Gurpreet; Kirwan, Barry

1998-01-01

Accidents such as Piper Alpha have increased concern about the effects of human errors in complex systems. Such accidents can in theory be predicted and prevented by risk assessment, and in particular human reliability assessment (HRA), but HRA ideally requires qualitative and quantitative human error data. A research initiative at the University of Birmingham led to the development of CORE-DATA, a Computerised Human Error Data Base. This system currently contains a reasonably large number of human error data points, collected from a variety of mainly nuclear-power related sources. This article outlines a recent offshore data collection study, concerned with collecting lifeboat evacuation data. Data collection methods are outlined and a selection of human error probabilities generated as a result of the study are provided. These data give insights into the type of errors and human failure rates that could be utilised to support offshore risk analyses

Visual acuity measures do not reliably detect childhood refractive error--an epidemiological study.

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Lisa O'Donoghue

Full Text Available PURPOSE: To investigate the utility of uncorrected visual acuity measures in screening for refractive error in white school children aged 6-7-years and 12-13-years. METHODS: The Northern Ireland Childhood Errors of Refraction (NICER study used a stratified random cluster design to recruit children from schools in Northern Ireland. Detailed eye examinations included assessment of logMAR visual acuity and cycloplegic autorefraction. Spherical equivalent refractive data from the right eye were used to classify significant refractive error as myopia of at least 1DS, hyperopia as greater than +3.50DS and astigmatism as greater than 1.50DC, whether it occurred in isolation or in association with myopia or hyperopia. RESULTS: Results are presented from 661 white 12-13-year-old and 392 white 6-7-year-old school-children. Using a cut-off of uncorrected visual acuity poorer than 0.20 logMAR to detect significant refractive error gave a sensitivity of 50% and specificity of 92% in 6-7-year-olds and 73% and 93% respectively in 12-13-year-olds. In 12-13-year-old children a cut-off of poorer than 0.20 logMAR had a sensitivity of 92% and a specificity of 91% in detecting myopia and a sensitivity of 41% and a specificity of 84% in detecting hyperopia. CONCLUSIONS: Vision screening using logMAR acuity can reliably detect myopia, but not hyperopia or astigmatism in school-age children. Providers of vision screening programs should be cognisant that where detection of uncorrected hyperopic and/or astigmatic refractive error is an aspiration, current UK protocols will not effectively deliver.

Medication knowledge, certainty, and risk of errors in health care: a cross-sectional study

Directory of Open Access Journals (Sweden)

Johansson Inger

2011-07-01

Full Text Available Abstract Background Medication errors are often involved in reported adverse events. Drug therapy, prescribed by physicians, is mostly carried out by nurses, who are expected to master all aspects of medication. Research has revealed the need for improved knowledge in drug dose calculation, and medication knowledge as a whole is poorly investigated. The purpose of this survey was to study registered nurses' medication knowledge, certainty and estimated risk of errors, and to explore factors associated with good results. Methods Nurses from hospitals and primary health care establishments were invited to carry out a multiple-choice test in pharmacology, drug management and drug dose calculations (score range 0-14. Self-estimated certainty in each answer was recorded, graded from 0 = very uncertain to 3 = very certain. Background characteristics and sense of coping were recorded. Risk of error was estimated by combining knowledge and certainty scores. The results are presented as mean (±SD. Results Two-hundred and three registered nurses participated (including 16 males, aged 42.0 (9.3 years with a working experience of 12.4 (9.2 years. Knowledge scores in pharmacology, drug management and drug dose calculations were 10.3 (1.6, 7.5 (1.6, and 11.2 (2.0, respectively, and certainty scores were 1.8 (0.4, 1.9 (0.5, and 2.0 (0.6, respectively. Fifteen percent of the total answers showed a high risk of error, with 25% in drug management. Independent factors associated with high medication knowledge were working in hospitals (p Conclusions Medication knowledge was found to be unsatisfactory among practicing nurses, with a significant risk for medication errors. The study revealed a need to improve the nurses' basic knowledge, especially when referring to drug management.

Study of dosimetry errors in the framework of a concerted international study about the risk of cancer in nuclear industry workers. Study of the errors made on dose estimations of 100 to 3000 keV photons

International Nuclear Information System (INIS)

Thierry Chef, I.

2000-01-01

Ionizing radiations are uncontested factors of cancer risk and the radioprotection standards are defined on the basis of epidemiological studies of persons exposed to high doses of radiations (atomic bombs and therapeutic medical exposures). An epidemiological study of cancer risk has been carried out on nuclear industry workers from 17 countries in order to check these standards and to directly evaluate the risk linked with long duration exposures to low doses. The techniques used to measure the workers' doses have changed with time and these evolutions have been different in the different countries considered. The study of dosimetry errors aims at estimating the compatibility of the doses with respect to the periods of time and to the countries, and at quantifying the errors that could have disturbed the dose measurements during the first years and their consideration in the risk estimation. A compilation of the information available about dosimetry in the participating countries has been performed and the main sources of errors have been identified. Experiments have been carried out to test the response of the dosimeters used and to evaluate the conditions of exposure inside the companies. The biases and uncertainties have been estimated per company and per period of time and the most important correspond to the oldest measurements performed. This study contributes also to improve the knowledge of the working conditions and of the preciseness of dose estimations. (J.S.)

Wind power error estimation in resource assessments.

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Osvaldo Rodríguez

Full Text Available Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies.

Wind power error estimation in resource assessments.

Science.gov (United States)

Rodríguez, Osvaldo; Del Río, Jesús A; Jaramillo, Oscar A; Martínez, Manuel

2015-01-01

Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies.

Human errors related to maintenance and modifications

International Nuclear Information System (INIS)

Laakso, K.; Pyy, P.; Reiman, L.

1998-01-01

The focus in human reliability analysis (HRA) relating to nuclear power plants has traditionally been on human performance in disturbance conditions. On the other hand, some studies and incidents have shown that also maintenance errors, which have taken place earlier in plant history, may have an impact on the severity of a disturbance, e.g. if they disable safety related equipment. Especially common cause and other dependent failures of safety systems may significantly contribute to the core damage risk. The first aim of the study was to identify and give examples of multiple human errors which have penetrated the various error detection and inspection processes of plant safety barriers. Another objective was to generate numerical safety indicators to describe and forecast the effectiveness of maintenance. A more general objective was to identify needs for further development of maintenance quality and planning. In the first phase of this operational experience feedback analysis, human errors recognisable in connection with maintenance were looked for by reviewing about 4400 failure and repair reports and some special reports which cover two nuclear power plant units on the same site during 1992-94. A special effort was made to study dependent human errors since they are generally the most serious ones. An in-depth root cause analysis was made for 14 dependent errors by interviewing plant maintenance foremen and by thoroughly analysing the errors. A more simple treatment was given to maintenance-related single errors. The results were shown as a distribution of errors among operating states i.a. as regards the following matters: in what operational state the errors were committed and detected; in what operational and working condition the errors were detected, and what component and error type they were related to. These results were presented separately for single and dependent maintenance-related errors. As regards dependent errors, observations were also made

An Experimental Study of Medical Error Explanations: Do Apology, Empathy, Corrective Action, and Compensation Alter Intentions and Attitudes?

Science.gov (United States)

Nazione, Samantha; Pace, Kristin

2015-01-01

Medical malpractice lawsuits are a growing problem in the United States, and there is much controversy regarding how to best address this problem. The medical error disclosure framework suggests that apologizing, expressing empathy, engaging in corrective action, and offering compensation after a medical error may improve the provider-patient relationship and ultimately help reduce the number of medical malpractice lawsuits patients bring to medical providers. This study provides an experimental examination of the medical error disclosure framework and its effect on amount of money requested in a lawsuit, negative intentions, attitudes, and anger toward the provider after a medical error. Results suggest empathy may play a large role in providing positive outcomes after a medical error.

Barriers to the medication error reporting process within the Irish National Ambulance Service, a focus group study.

Science.gov (United States)

Byrne, Eamonn; Bury, Gerard

2018-02-08

Incident reporting is vital to identifying pre-hospital medication safety issues because literature suggests that the majority of errors pre-hospital are self-identified. In 2016, the National Ambulance Service (NAS) reported 11 medication errors to the national body with responsibility for risk management and insurance cover. The Health Information and Quality Authority in 2014 stated that reporting of clinical incidents, of which medication errors are a subset, was not felt to be representative of the actual events occurring. Even though reporting systems are in place, the levels appear to be well below what might be expected. Little data is available to explain this apparent discrepancy. To identify, investigate and document the barriers to medication error reporting within the NAS. An independent moderator led four focus groups in March of 2016. A convenience sample of 18 frontline Paramedics and Advanced Paramedics from Cork City and County discussed medication errors and the medication error reporting process. The sessions were recorded and anonymised, and the data was analysed using a process of thematic analysis. Practitioners understood the value of reporting errors. Barriers to reporting included fear of consequences and ridicule, procedural ambiguity, lack of feedback and a perceived lack of both consistency and confidentiality. The perceived consequences for making an error included professional, financial, litigious and psychological. Staff appeared willing to admit errors in a psychologically safe environment. Barriers to reporting are in line with international evidence. Time constraints prevented achievement of thematic saturation. Further study is warranted.

Error and discrepancy in radiology: inevitable or avoidable?

Science.gov (United States)

Brady, Adrian P

2017-02-01

Errors and discrepancies in radiology practice are uncomfortably common, with an estimated day-to-day rate of 3-5% of studies reported, and much higher rates reported in many targeted studies. Nonetheless, the meaning of the terms "error" and "discrepancy" and the relationship to medical negligence are frequently misunderstood. This review outlines the incidence of such events, the ways they can be categorized to aid understanding, and potential contributing factors, both human- and system-based. Possible strategies to minimise error are considered, along with the means of dealing with perceived underperformance when it is identified. The inevitability of imperfection is explained, while the importance of striving to minimise such imperfection is emphasised. • Discrepancies between radiology reports and subsequent patient outcomes are not inevitably errors. • Radiologist reporting performance cannot be perfect, and some errors are inevitable. • Error or discrepancy in radiology reporting does not equate negligence. • Radiologist errors occur for many reasons, both human- and system-derived. • Strategies exist to minimise error causes and to learn from errors made.

Conflict monitoring in speech processing : An fMRI study of error detection in speech production and perception

NARCIS (Netherlands)

Gauvin, Hanna; De Baene, W.; Brass, Marcel; Hartsuiker, Robert

2016-01-01

To minimize the number of errors in speech, and thereby facilitate communication, speech is monitored before articulation. It is, however, unclear at which level during speech production monitoring takes place, and what mechanisms are used to detect and correct errors. The present study investigated

Generalized Gaussian Error Calculus

CERN Document Server

Grabe, Michael

2010-01-01

For the first time in 200 years Generalized Gaussian Error Calculus addresses a rigorous, complete and self-consistent revision of the Gaussian error calculus. Since experimentalists realized that measurements in general are burdened by unknown systematic errors, the classical, widespread used evaluation procedures scrutinizing the consequences of random errors alone turned out to be obsolete. As a matter of course, the error calculus to-be, treating random and unknown systematic errors side by side, should ensure the consistency and traceability of physical units, physical constants and physical quantities at large. The generalized Gaussian error calculus considers unknown systematic errors to spawn biased estimators. Beyond, random errors are asked to conform to the idea of what the author calls well-defined measuring conditions. The approach features the properties of a building kit: any overall uncertainty turns out to be the sum of a contribution due to random errors, to be taken from a confidence inter...

Technology and medication errors: impact in nursing homes.

Science.gov (United States)

Baril, Chantal; Gascon, Viviane; St-Pierre, Liette; Lagacé, Denis

2014-01-01

The purpose of this paper is to study a medication distribution technology's (MDT) impact on medication errors reported in public nursing homes in Québec Province. The work was carried out in six nursing homes (800 patients). Medication error data were collected from nursing staff through a voluntary reporting process before and after MDT was implemented. The errors were analysed using: totals errors; medication error type; severity and patient consequences. A statistical analysis verified whether there was a significant difference between the variables before and after introducing MDT. The results show that the MDT detected medication errors. The authors' analysis also indicates that errors are detected more rapidly resulting in less severe consequences for patients. MDT is a step towards safer and more efficient medication processes. Our findings should convince healthcare administrators to implement technology such as electronic prescriber or bar code medication administration systems to improve medication processes and to provide better healthcare to patients. Few studies have been carried out in long-term healthcare facilities such as nursing homes. The authors' study extends what is known about MDT's impact on medication errors in nursing homes.

Medication errors : the impact of prescribing and transcribing errors on preventable harm in hospitalised patients

NARCIS (Netherlands)

van Doormaal, J.E.; van der Bemt, P.M.L.A.; Mol, P.G.M.; Egberts, A.C.G.; Haaijer-Ruskamp, F.M.; Kosterink, J.G.W.; Zaal, Rianne J.

Background: Medication errors (MEs) affect patient safety to a significant extent. Because these errors can lead to preventable adverse drug events (pADEs), it is important to know what type of ME is the most prevalent cause of these pADEs. This study determined the impact of the various types of

[Errors in Peruvian medical journals references].

Science.gov (United States)

Huamaní, Charles; Pacheco-Romero, José

2009-01-01

References are fundamental in our studies; an adequate selection is asimportant as an adequate description. To determine the number of errors in a sample of references found in Peruvian medical journals. We reviewed 515 scientific papers references selected by systematic randomized sampling and corroborated reference information with the original document or its citation in Pubmed, LILACS or SciELO-Peru. We found errors in 47,6% (245) of the references, identifying 372 types of errors; the most frequent were errors in presentation style (120), authorship (100) and title (100), mainly due to spelling mistakes (91). References error percentage was high, varied and multiple. We suggest systematic revision of references in the editorial process as well as to extend the discussion on this theme. references, periodicals, research, bibliometrics.

Study of wavefront error and polarization of a side mounted infrared window

Science.gov (United States)

Liu, Jiaguo; Li, Lin; Hu, Xinqi; Yu, Xin

2008-03-01

The wavefront error and polarization of a side mounted infrared window made of ZnS are studied. The Infrared windows suffer from temperature gradient and stress during their launch process. Generally, the gradient in temperature changes the refractive index of the material whereas stress produces deformation and birefringence. In this paper, a thermal finite element analysis (FEA) of an IR window is presented. For this purpose, we employed an FEA program Ansys to obtain the time-varying temperature field. The deformation and stress of the window are derived from a structural FEA with the aerodynamic force and the temperature field previously obtained as being the loads. The deformation, temperature field, stress field, ray tracing and Jones Calculus are used to calculate the wavefront error and the change of polarization state.

The northern European geoid: a case study on long-wavelength geoid errors

DEFF Research Database (Denmark)

Omang, O.C.D.; Forsberg, René

2002-01-01

. This method of removing lower-order terms in the Stokes kernel appears to improve the geoid. The best fit to the global positioning system (GPS) leveling points is obtained with a degree of modification of approximately 30. In addition to the study of modification errors, the results of different methods...

An adaptive orienting theory of error processing.

Science.gov (United States)

Wessel, Jan R

2018-03-01

The ability to detect and correct action errors is paramount to safe and efficient goal-directed behaviors. Existing work on the neural underpinnings of error processing and post-error behavioral adaptations has led to the development of several mechanistic theories of error processing. These theories can be roughly grouped into adaptive and maladaptive theories. While adaptive theories propose that errors trigger a cascade of processes that will result in improved behavior after error commission, maladaptive theories hold that error commission momentarily impairs behavior. Neither group of theories can account for all available data, as different empirical studies find both impaired and improved post-error behavior. This article attempts a synthesis between the predictions made by prominent adaptive and maladaptive theories. Specifically, it is proposed that errors invoke a nonspecific cascade of processing that will rapidly interrupt and inhibit ongoing behavior and cognition, as well as orient attention toward the source of the error. It is proposed that this cascade follows all unexpected action outcomes, not just errors. In the case of errors, this cascade is followed by error-specific, controlled processing, which is specifically aimed at (re)tuning the existing task set. This theory combines existing predictions from maladaptive orienting and bottleneck theories with specific neural mechanisms from the wider field of cognitive control, including from error-specific theories of adaptive post-error processing. The article aims to describe the proposed framework and its implications for post-error slowing and post-error accuracy, propose mechanistic neural circuitry for post-error processing, and derive specific hypotheses for future empirical investigations. © 2017 Society for Psychophysiological Research.

Prevalence, Nature, Severity and Risk Factors for Prescribing Errors in Hospital Inpatients: Prospective Study in 20 UK Hospitals.

Science.gov (United States)

Ashcroft, Darren M; Lewis, Penny J; Tully, Mary P; Farragher, Tracey M; Taylor, David; Wass, Valerie; Williams, Steven D; Dornan, Tim

2015-09-01

It has been suggested that doctors in their first year of post-graduate training make a disproportionate number of prescribing errors. This study aimed to compare the prevalence of prescribing errors made by first-year post-graduate doctors with that of errors by senior doctors and non-medical prescribers and to investigate the predictors of potentially serious prescribing errors. Pharmacists in 20 hospitals over 7 prospectively selected days collected data on the number of medication orders checked, the grade of prescriber and details of any prescribing errors. Logistic regression models (adjusted for clustering by hospital) identified factors predicting the likelihood of prescribing erroneously and the severity of prescribing errors. Pharmacists reviewed 26,019 patients and 124,260 medication orders; 11,235 prescribing errors were detected in 10,986 orders. The mean error rate was 8.8 % (95 % confidence interval [CI] 8.6-9.1) errors per 100 medication orders. Rates of errors for all doctors in training were significantly higher than rates for medical consultants. Doctors who were 1 year (odds ratio [OR] 2.13; 95 % CI 1.80-2.52) or 2 years in training (OR 2.23; 95 % CI 1.89-2.65) were more than twice as likely to prescribe erroneously. Prescribing errors were 70 % (OR 1.70; 95 % CI 1.61-1.80) more likely to occur at the time of hospital admission than when medication orders were issued during the hospital stay. No significant differences in severity of error were observed between grades of prescriber. Potentially serious errors were more likely to be associated with prescriptions for parenteral administration, especially for cardiovascular or endocrine disorders. The problem of prescribing errors in hospitals is substantial and not solely a problem of the most junior medical prescribers, particularly for those errors most likely to cause significant patient harm. Interventions are needed to target these high-risk errors by all grades of staff and hence

A Hybrid Unequal Error Protection / Unequal Error Resilience ...

African Journals Online (AJOL)

The quality layers are then assigned an Unequal Error Resilience to synchronization loss by unequally allocating the number of headers available for synchronization to them. Following that Unequal Error Protection against channel noise is provided to the layers by the use of Rate Compatible Punctured Convolutional ...

Comprehensive Anti-error Study on Power Grid Dispatching Based on Regional Regulation and Integration

Science.gov (United States)

Zhang, Yunju; Chen, Zhongyi; Guo, Ming; Lin, Shunsheng; Yan, Yinyang

2018-01-01

With the large capacity of the power system, the development trend of the large unit and the high voltage, the scheduling operation is becoming more frequent and complicated, and the probability of operation error increases. This paper aims at the problem of the lack of anti-error function, single scheduling function and low working efficiency for technical support system in regional regulation and integration, the integrated construction of the error prevention of the integrated architecture of the system of dispatching anti - error of dispatching anti - error of power network based on cloud computing has been proposed. Integrated system of error prevention of Energy Management System, EMS, and Operation Management System, OMS have been constructed either. The system architecture has good scalability and adaptability, which can improve the computational efficiency, reduce the cost of system operation and maintenance, enhance the ability of regional regulation and anti-error checking with broad development prospects.

Error field considerations for BPX

International Nuclear Information System (INIS)

LaHaye, R.J.

1992-01-01

Irregularities in the position of poloidal and/or toroidal field coils in tokamaks produce resonant toroidal asymmetries in the vacuum magnetic fields. Otherwise stable tokamak discharges become non-linearly unstable to disruptive locked modes when subjected to low level error fields. Because of the field errors, magnetic islands are produced which would not otherwise occur in tearing mode table configurations; a concomitant reduction of the total confinement can result. Poloidal and toroidal asymmetries arise in the heat flux to the divertor target. In this paper, the field errors from perturbed BPX coils are used in a field line tracing code of the BPX equilibrium to study these deleterious effects. Limits on coil irregularities for device design and fabrication are computed along with possible correcting coils for reducing such field errors

Pediatric Nurses' Perceptions of Medication Safety and Medication Error: A Mixed Methods Study.

Science.gov (United States)

Alomari, Albara; Wilson, Val; Solman, Annette; Bajorek, Beata; Tinsley, Patricia

2017-05-30

This study aims to outline the current workplace culture of medication practice in a pediatric medical ward. The objective is to explore the perceptions of nurses in a pediatric clinical setting as to why medication administration errors occur. As nurses have a central role in the medication process, it is essential to explore nurses' perceptions of the factors influencing the medication process. Without this understanding, it is difficult to develop effective prevention strategies aimed at reducing medication administration errors. Previous studies were limited to exploring a single and specific aspect of medication safety. The methods used in these studies were limited to survey designs which may lead to incomplete or inadequate information being provided. This study is phase 1 on an action research project. Data collection included a direct observation of nurses during medication preparation and administration, audit based on the medication policy, and guidelines and focus groups with nursing staff. A thematic analysis was undertaken by each author independently to analyze the observation notes and focus group transcripts. Simple descriptive statistics were used to analyze the audit data. The study was conducted in a specialized pediatric medical ward. Four key themes were identified from the combined quantitative and qualitative data: (1) understanding medication errors, (2) the busy-ness of nurses, (3) the physical environment, and (4) compliance with medication policy and practice guidelines. Workload, frequent interruptions to process, poor physical environment design, lack of preparation space, and impractical medication policies are identified as barriers to safe medication practice. Overcoming these barriers requires organizations to review medication process policies and engage nurses more in medication safety research and in designing clinical guidelines for their own practice.

Naming game with learning errors in communications

OpenAIRE

Lou, Yang; Chen, Guanrong

2014-01-01

Naming game simulates the process of naming an objective by a population of agents organized in a certain communication network topology. By pair-wise iterative interactions, the population reaches a consensus state asymptotically. In this paper, we study naming game with communication errors during pair-wise conversations, where errors are represented by error rates in a uniform probability distribution. First, a model of naming game with learning errors in communications (NGLE) is proposed....

Study on the methodology for predicting and preventing errors to improve reliability of maintenance task in nuclear power plant

International Nuclear Information System (INIS)

Hanafusa, Hidemitsu; Iwaki, Toshio; Embrey, D.

2000-01-01

The objective of this study was to develop and effective methodology for predicting and preventing errors in nuclear power plant maintenance tasks. A method was established by which chief maintenance personnel can predict and reduce errors when reviewing the maintenance procedures and while referring to maintenance supporting systems and methods in other industries including aviation and chemical plant industries. The method involves the following seven steps: 1. Identification of maintenance tasks. 2. Specification of important tasks affecting safety. 3. Assessment of human errors occurring during important tasks. 4. Identification of Performance Degrading Factors. 5. Dividing important tasks into sub-tasks. 6. Extraction of errors using Predictive Human Error Analysis (PHEA). 7. Development of strategies for reducing errors and for recovering from errors. By way of a trial, this method was applied to the pump maintenance procedure in nuclear power plants. This method is believed to be capable of identifying the expected errors in important tasks and supporting the development of error reduction measures. By applying this method, the number of accidents resulting form human errors during maintenance can be reduced. Moreover, the maintenance support base using computers was developed. (author)

Learning from prescribing errors

OpenAIRE

Dean, B

2002-01-01



 The importance of learning from medical error has recently received increasing emphasis. This paper focuses on prescribing errors and argues that, while learning from prescribing errors is a laudable goal, there are currently barriers that can prevent this occurring. Learning from errors can take place on an individual level, at a team level, and across an organisation. Barriers to learning from prescribing errors include the non-discovery of many prescribing errors, lack of feedback to th...

Everyday memory errors in older adults.

Science.gov (United States)

Ossher, Lynn; Flegal, Kristin E; Lustig, Cindy

2013-01-01

Despite concern about cognitive decline in old age, few studies document the types and frequency of memory errors older adults make in everyday life. In the present study, 105 healthy older adults completed the Everyday Memory Questionnaire (EMQ; Sunderland, Harris, & Baddeley, 1983 , Journal of Verbal Learning and Verbal Behavior, 22, 341), indicating what memory errors they had experienced in the last 24 hours, the Memory Self-Efficacy Questionnaire (MSEQ; West, Thorn, & Bagwell, 2003 , Psychology and Aging, 18, 111), and other neuropsychological and cognitive tasks. EMQ and MSEQ scores were unrelated and made separate contributions to variance on the Mini Mental State Exam (MMSE; Folstein, Folstein, & McHugh, 1975 , Journal of Psychiatric Research, 12, 189), suggesting separate constructs. Tip-of-the-tongue errors were the most commonly reported, and the EMQ Faces/Places and New Things subscales were most strongly related to MMSE. These findings may help training programs target memory errors commonly experienced by older adults, and suggest which types of memory errors could indicate cognitive declines of clinical concern.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

Barriers to medication error reporting among hospital nurses.

Science.gov (United States)

Rutledge, Dana N; Retrosi, Tina; Ostrowski, Gary

2018-03-01

The study purpose was to report medication error reporting barriers among hospital nurses, and to determine validity and reliability of an existing medication error reporting barriers questionnaire. Hospital medication errors typically occur between ordering of a medication to its receipt by the patient with subsequent staff monitoring. To decrease medication errors, factors surrounding medication errors must be understood; this requires reporting by employees. Under-reporting can compromise patient safety by disabling improvement efforts. This 2017 descriptive study was part of a larger workforce engagement study at a faith-based Magnet ® -accredited community hospital in California (United States). Registered nurses (~1,000) were invited to participate in the online survey via email. Reported here are sample demographics (n = 357) and responses to the 20-item medication error reporting barriers questionnaire. Using factor analysis, four factors that accounted for 67.5% of the variance were extracted. These factors (subscales) were labelled Fear, Cultural Barriers, Lack of Knowledge/Feedback and Practical/Utility Barriers; each demonstrated excellent internal consistency. The medication error reporting barriers questionnaire, originally developed in long-term care, demonstrated good validity and excellent reliability among hospital nurses. Substantial proportions of American hospital nurses (11%-48%) considered specific factors as likely reporting barriers. Average scores on most barrier items were categorised "somewhat unlikely." The highest six included two barriers concerning the time-consuming nature of medication error reporting and four related to nurses' fear of repercussions. Hospitals need to determine the presence of perceived barriers among nurses using questionnaires such as the medication error reporting barriers and work to encourage better reporting. Barriers to medication error reporting make it less likely that nurses will report medication

A Study of Trial and Error Learning in Technology, Engineering, and Design Education

Science.gov (United States)

Franzen, Marissa Marie Sloan

2016-01-01

The purpose of this research study was to determine if trial and error learning was an effective, practical, and efficient learning method for Technology, Engineering, and Design Education students at the post-secondary level. A mixed methods explanatory research design was used to measure the viability of the learning source. The study sample was…

Random and Systematic Errors Share in Total Error of Probes for CNC Machine Tools

Directory of Open Access Journals (Sweden)

Adam Wozniak

2018-03-01

Full Text Available Probes for CNC machine tools, as every measurement device, have accuracy limited by random errors and by systematic errors. Random errors of these probes are described by a parameter called unidirectional repeatability. Manufacturers of probes for CNC machine tools usually specify only this parameter, while parameters describing systematic errors of the probes, such as pre-travel variation or triggering radius variation, are used rarely. Systematic errors of the probes, linked to the differences in pre-travel values for different measurement directions, can be corrected or compensated, but it is not a widely used procedure. In this paper, the share of systematic errors and random errors in total error of exemplary probes are determined. In the case of simple, kinematic probes, systematic errors are much greater than random errors, so compensation would significantly reduce the probing error. Moreover, it shows that in the case of kinematic probes commonly specified unidirectional repeatability is significantly better than 2D performance. However, in the case of more precise strain-gauge probe systematic errors are of the same order as random errors, which means that errors correction or compensation, in this case, would not yield any significant benefits.

Quantum error-correcting code for ternary logic

Science.gov (United States)

Majumdar, Ritajit; Basu, Saikat; Ghosh, Shibashis; Sur-Kolay, Susmita

2018-05-01

Ternary quantum systems are being studied because they provide more computational state space per unit of information, known as qutrit. A qutrit has three basis states, thus a qubit may be considered as a special case of a qutrit where the coefficient of one of the basis states is zero. Hence both (2 ×2 ) -dimensional and (3 ×3 ) -dimensional Pauli errors can occur on qutrits. In this paper, we (i) explore the possible (2 ×2 ) -dimensional as well as (3 ×3 ) -dimensional Pauli errors in qutrits and show that any pairwise bit swap error can be expressed as a linear combination of shift errors and phase errors, (ii) propose a special type of error called a quantum superposition error and show its equivalence to arbitrary rotation, (iii) formulate a nine-qutrit code which can correct a single error in a qutrit, and (iv) provide its stabilizer and circuit realization.

Acoustic Evidence for Phonologically Mismatched Speech Errors

Science.gov (United States)

Gormley, Andrea

2015-01-01

Speech errors are generally said to accommodate to their new phonological context. This accommodation has been validated by several transcription studies. The transcription methodology is not the best choice for detecting errors at this level, however, as this type of error can be difficult to perceive. This paper presents an acoustic analysis of…

The relationship between automation complexity and operator error

International Nuclear Information System (INIS)

Ogle, Russell A.; Morrison, Delmar 'Trey'; Carpenter, Andrew R.

2008-01-01

One of the objectives of process automation is to improve the safety of plant operations. Manual operation, it is often argued, provides too many opportunities for operator error. By this argument, process automation should decrease the risk of accidents caused by operator error. However, some accident theorists have argued that while automation may eliminate some types of operator error, it may create new varieties of error. In this paper we present six case studies of explosions involving operator error in an automated process facility. Taken together, these accidents resulted in six fatalities, 30 injuries and hundreds of millions of dollars in property damage. The case studies are divided into two categories: low and high automation complexity (three case studies each). The nature of the operator error was dependent on the level of automation complexity. For each case study, we also consider the contribution of the existing engineering controls such as safety instrumented systems (SIS) or safety critical devices (SCD) and explore why they were insufficient to prevent, or mitigate, the severity of the explosion

[Medication error management climate and perception for system use according to construction of medication error prevention system].

Science.gov (United States)

Kim, Myoung Soo

2012-08-01

The purpose of this cross-sectional study was to examine current status of IT-based medication error prevention system construction and the relationships among system construction, medication error management climate and perception for system use. The participants were 124 patient safety chief managers working for 124 hospitals with over 300 beds in Korea. The characteristics of the participants, construction status and perception of systems (electric pharmacopoeia, electric drug dosage calculation system, computer-based patient safety reporting and bar-code system) and medication error management climate were measured in this study. The data were collected between June and August 2011. Descriptive statistics, partial Pearson correlation and MANCOVA were used for data analysis. Electric pharmacopoeia were constructed in 67.7% of participating hospitals, computer-based patient safety reporting systems were constructed in 50.8%, electric drug dosage calculation systems were in use in 32.3%. Bar-code systems showed up the lowest construction rate at 16.1% of Korean hospitals. Higher rates of construction of IT-based medication error prevention systems resulted in greater safety and a more positive error management climate prevailed. The supportive strategies for improving perception for use of IT-based systems would add to system construction, and positive error management climate would be more easily promoted.

Advancing the research agenda for diagnostic error reduction.

Science.gov (United States)

Zwaan, Laura; Schiff, Gordon D; Singh, Hardeep

2013-10-01

Diagnostic errors remain an underemphasised and understudied area of patient safety research. We briefly summarise the methods that have been used to conduct research on epidemiology, contributing factors and interventions related to diagnostic error and outline directions for future research. Research methods that have studied epidemiology of diagnostic error provide some estimate on diagnostic error rates. However, there appears to be a large variability in the reported rates due to the heterogeneity of definitions and study methods used. Thus, future methods should focus on obtaining more precise estimates in different settings of care. This would lay the foundation for measuring error rates over time to evaluate improvements. Research methods have studied contributing factors for diagnostic error in both naturalistic and experimental settings. Both approaches have revealed important and complementary information. Newer conceptual models from outside healthcare are needed to advance the depth and rigour of analysis of systems and cognitive insights of causes of error. While the literature has suggested many potentially fruitful interventions for reducing diagnostic errors, most have not been systematically evaluated and/or widely implemented in practice. Research is needed to study promising intervention areas such as enhanced patient involvement in diagnosis, improving diagnosis through the use of electronic tools and identification and reduction of specific diagnostic process 'pitfalls' (eg, failure to conduct appropriate diagnostic evaluation of a breast lump after a 'normal' mammogram). The last decade of research on diagnostic error has made promising steps and laid a foundation for more rigorous methods to advance the field.

The Nature of Error in Adolescent Student Writing

Science.gov (United States)

Wilcox, Kristen Campbell; Yagelski, Robert; Yu, Fang

2014-01-01

This study examined the nature and frequency of error in high school native English speaker (L1) and English learner (L2) writing. Four main research questions were addressed: Are there significant differences in students' error rates in English language arts (ELA) and social studies? Do the most common errors made by students differ in ELA…

Numerical optimization with computational errors

CERN Document Server

Zaslavski, Alexander J

2016-01-01

This book studies the approximate solutions of optimization problems in the presence of computational errors. A number of results are presented on the convergence behavior of algorithms in a Hilbert space; these algorithms are examined taking into account computational errors. The author illustrates that algorithms generate a good approximate solution, if computational errors are bounded from above by a small positive constant. Known computational errors are examined with the aim of determining an approximate solution. Researchers and students interested in the optimization theory and its applications will find this book instructive and informative. This monograph contains 16 chapters; including a chapters devoted to the subgradient projection algorithm, the mirror descent algorithm, gradient projection algorithm, the Weiszfelds method, constrained convex minimization problems, the convergence of a proximal point method in a Hilbert space, the continuous subgradient method, penalty methods and Newton’s meth...

[Medication errors in Spanish intensive care units].

Science.gov (United States)

Merino, P; Martín, M C; Alonso, A; Gutiérrez, I; Alvarez, J; Becerril, F

2013-01-01

To estimate the incidence of medication errors in Spanish intensive care units. Post hoc study of the SYREC trial. A longitudinal observational study carried out during 24 hours in patients admitted to the ICU. Spanish intensive care units. Patients admitted to the intensive care unit participating in the SYREC during the period of study. Risk, individual risk, and rate of medication errors. The final study sample consisted of 1017 patients from 79 intensive care units; 591 (58%) were affected by one or more incidents. Of these, 253 (43%) had at least one medication-related incident. The total number of incidents reported was 1424, of which 350 (25%) were medication errors. The risk of suffering at least one incident was 22% (IQR: 8-50%) while the individual risk was 21% (IQR: 8-42%). The medication error rate was 1.13 medication errors per 100 patient-days of stay. Most incidents occurred in the prescription (34%) and administration (28%) phases, 16% resulted in patient harm, and 82% were considered "totally avoidable". Medication errors are among the most frequent types of incidents in critically ill patients, and are more common in the prescription and administration stages. Although most such incidents have no clinical consequences, a significant percentage prove harmful for the patient, and a large proportion are avoidable. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Common Errors in Ecological Data Sharing

Directory of Open Access Journals (Sweden)

Robert B. Cook

2013-04-01

Full Text Available Objectives: (1 to identify common errors in data organization and metadata completeness that would preclude a “reader” from being able to interpret and re-use the data for a new purpose; and (2 to develop a set of best practices derived from these common errors that would guide researchers in creating more usable data products that could be readily shared, interpreted, and used.Methods: We used directed qualitative content analysis to assess and categorize data and metadata errors identified by peer reviewers of data papers published in the Ecological Society of America’s (ESA Ecological Archives. Descriptive statistics provided the relative frequency of the errors identified during the peer review process.Results: There were seven overarching error categories: Collection & Organization, Assure, Description, Preserve, Discover, Integrate, and Analyze/Visualize. These categories represent errors researchers regularly make at each stage of the Data Life Cycle. Collection & Organization and Description errors were some of the most common errors, both of which occurred in over 90% of the papers.Conclusions: Publishing data for sharing and reuse is error prone, and each stage of the Data Life Cycle presents opportunities for mistakes. The most common errors occurred when the researcher did not provide adequate metadata to enable others to interpret and potentially re-use the data. Fortunately, there are ways to minimize these mistakes through carefully recording all details about study context, data collection, QA/ QC, and analytical procedures from the beginning of a research project and then including this descriptive information in the metadata.

Comparing classifiers for pronunciation error detection

NARCIS (Netherlands)

Strik, H.; Truong, K.; Wet, F. de; Cucchiarini, C.

2007-01-01

Providing feedback on pronunciation errors in computer assisted language learning systems requires that pronunciation errors be detected automatically. In the present study we compare four types of classifiers that can be used for this purpose: two acoustic-phonetic classifiers (one of which employs

Prescribing errors in a Brazilian neonatal intensive care unit

Directory of Open Access Journals (Sweden)

Ana Paula Cezar Machado

2015-12-01

Full Text Available Abstract Pediatric patients, especially those admitted to the neonatal intensive care unit (ICU, are highly vulnerable to medication errors. This study aimed to measure the prescription error rate in a university hospital neonatal ICU and to identify susceptible patients, types of errors, and the medicines involved. The variables related to medicines prescribed were compared to the Neofax prescription protocol. The study enrolled 150 newborns and analyzed 489 prescription order forms, with 1,491 medication items, corresponding to 46 drugs. Prescription error rate was 43.5%. Errors were found in dosage, intervals, diluents, and infusion time, distributed across 7 therapeutic classes. Errors were more frequent in preterm newborns. Diluent and dosing were the most frequent sources of errors. The therapeutic classes most involved in errors were antimicrobial agents and drugs that act on the nervous and cardiovascular systems.

Medication Administration Errors Involving Paediatric In-Patients in a ...

African Journals Online (AJOL)

The drug mostly associated with error was gentamicin with 29 errors (1.2 %). Conclusion: During the study, a high frequency of error was observed. There is a need to modify the way information is handled and shared by professionals as wrong time error was the most implicated error. Attention should also be given to IV ...

Medication Errors: New EU Good Practice Guide on Risk Minimisation and Error Prevention.

Science.gov (United States)

Goedecke, Thomas; Ord, Kathryn; Newbould, Victoria; Brosch, Sabine; Arlett, Peter

2016-06-01

A medication error is an unintended failure in the drug treatment process that leads to, or has the potential to lead to, harm to the patient. Reducing the risk of medication errors is a shared responsibility between patients, healthcare professionals, regulators and the pharmaceutical industry at all levels of healthcare delivery. In 2015, the EU regulatory network released a two-part good practice guide on medication errors to support both the pharmaceutical industry and regulators in the implementation of the changes introduced with the EU pharmacovigilance legislation. These changes included a modification of the 'adverse reaction' definition to include events associated with medication errors, and the requirement for national competent authorities responsible for pharmacovigilance in EU Member States to collaborate and exchange information on medication errors resulting in harm with national patient safety organisations. To facilitate reporting and learning from medication errors, a clear distinction has been made in the guidance between medication errors resulting in adverse reactions, medication errors without harm, intercepted medication errors and potential errors. This distinction is supported by an enhanced MedDRA(®) terminology that allows for coding all stages of the medication use process where the error occurred in addition to any clinical consequences. To better understand the causes and contributing factors, individual case safety reports involving an error should be followed-up with the primary reporter to gather information relevant for the conduct of root cause analysis where this may be appropriate. Such reports should also be summarised in periodic safety update reports and addressed in risk management plans. Any risk minimisation and prevention strategy for medication errors should consider all stages of a medicinal product's life-cycle, particularly the main sources and types of medication errors during product development. This article

Association of medication errors with drug classifications, clinical units, and consequence of errors: Are they related?

Science.gov (United States)

Muroi, Maki; Shen, Jay J; Angosta, Alona

2017-02-01

Registered nurses (RNs) play an important role in safe medication administration and patient safety. This study examined a total of 1276 medication error (ME) incident reports made by RNs in hospital inpatient settings in the southwestern region of the United States. The most common drug class associated with MEs was cardiovascular drugs (24.7%). Among this class, anticoagulants had the most errors (11.3%). The antimicrobials was the second most common drug class associated with errors (19.1%) and vancomycin was the most common antimicrobial that caused errors in this category (6.1%). MEs occurred more frequently in the medical-surgical and intensive care units than any other hospital units. Ten percent of MEs reached the patients with harm and 11% reached the patients with increased monitoring. Understanding the contributing factors related to MEs, addressing and eliminating risk of errors across hospital units, and providing education and resources for nurses may help reduce MEs. Copyright © 2016 Elsevier Inc. All rights reserved.

The error performance analysis over cyclic redundancy check codes

Science.gov (United States)

Yoon, Hee B.

1991-06-01

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

The study of CD side to side error in line/space pattern caused by post-exposure bake effect

Science.gov (United States)

Huang, Jin; Guo, Eric; Ge, Haiming; Lu, Max; Wu, Yijun; Tian, Mingjing; Yan, Shichuan; Wang, Ran

2016-10-01

In semiconductor manufacturing, as the design rule has decreased, the ITRS roadmap requires crucial tighter critical dimension (CD) control. CD uniformity is one of the necessary parameters to assure good performance and reliable functionality of any integrated circuit (IC) [1] [2], and towards the advanced technology nodes, it is a challenge to control CD uniformity well. The study of corresponding CD Uniformity by tuning Post-Exposure bake (PEB) and develop process has some significant progress[3], but CD side to side error happening to some line/space pattern are still found in practical application, and the error has approached to over the uniformity tolerance. After details analysis, even though use several developer types, the CD side to side error has not been found significant relationship to the developing. In addition, it is impossible to correct the CD side to side error by electron beam correction as such error does not appear in all Line/Space pattern masks. In this paper the root cause of CD side to side error is analyzed and the PEB module process are optimized as a main factor for improvement of CD side to side error.

Error suppression and error correction in adiabatic quantum computation: non-equilibrium dynamics

International Nuclear Information System (INIS)

Sarovar, Mohan; Young, Kevin C

2013-01-01

While adiabatic quantum computing (AQC) has some robustness to noise and decoherence, it is widely believed that encoding, error suppression and error correction will be required to scale AQC to large problem sizes. Previous works have established at least two different techniques for error suppression in AQC. In this paper we derive a model for describing the dynamics of encoded AQC and show that previous constructions for error suppression can be unified with this dynamical model. In addition, the model clarifies the mechanisms of error suppression and allows the identification of its weaknesses. In the second half of the paper, we utilize our description of non-equilibrium dynamics in encoded AQC to construct methods for error correction in AQC by cooling local degrees of freedom (qubits). While this is shown to be possible in principle, we also identify the key challenge to this approach: the requirement of high-weight Hamiltonians. Finally, we use our dynamical model to perform a simplified thermal stability analysis of concatenated-stabilizer-code encoded many-body systems for AQC or quantum memories. This work is a companion paper to ‘Error suppression and error correction in adiabatic quantum computation: techniques and challenges (2013 Phys. Rev. X 3 041013)’, which provides a quantum information perspective on the techniques and limitations of error suppression and correction in AQC. In this paper we couch the same results within a dynamical framework, which allows for a detailed analysis of the non-equilibrium dynamics of error suppression and correction in encoded AQC. (paper)

Retinal dysfunction and refractive errors: an electrophysiological study of children

Science.gov (United States)

Flitcroft, D I; Adams, G G W; Robson, A G; Holder, G E

2005-01-01

Aims: To evaluate the relation between refractive error and electrophysiological retinal abnormalities in children referred for investigation of reduced vision. Methods: The study group comprised 123 consecutive patients referred over a 14 month period from the paediatric service of Moorfields Eye Hospital for electrophysiological investigation of reduced vision. Subjects were divided into five refractive categories according to their spectacle correction: high myopia (⩽−6D), low myopia (>−6D and ⩽−0.75D), emmetropia (>−0.75 and 1.5D) and ERG abnormalities (18/35 with high astigmatism v 20/88 without, χ2 test, p = 0.002). There was no significant variation in frequency of abnormalities between low myopes, emmetropes, and low hyperopes. The rate of abnormalities was very similar in both high myopes (8/15) and high hyperopes (5/10). Conclusions: High ametropia and astigmatism in children being investigated for poor vision are associated with a higher rate of retinal electrophysiological abnormalities. An increased rate of refractive errors in the presence of retinal pathology is consistent with the hypothesis that the retina is involved in the process of emmetropisation. Electrophysiological testing should be considered in cases of high ametropia in childhood to rule out associated retinal pathology. PMID:15774929

Comparison of Prediction-Error-Modelling Criteria

DEFF Research Database (Denmark)

Jørgensen, John Bagterp; Jørgensen, Sten Bay

2007-01-01

Single and multi-step prediction-error-methods based on the maximum likelihood and least squares criteria are compared. The prediction-error methods studied are based on predictions using the Kalman filter and Kalman predictors for a linear discrete-time stochastic state space model, which is a r...

Error and uncertainty in scientific practice

NARCIS (Netherlands)

Boumans, M.; Hon, G.; Petersen, A.C.

2014-01-01

Assessment of error and uncertainty is a vital component of both natural and social science. Empirical research involves dealing with all kinds of errors and uncertainties, yet there is significant variance in how such results are dealt with. Contributors to this volume present case studies of

Errors generated with the use of rectangular collimation

International Nuclear Information System (INIS)

Parks, E.T.

1991-01-01

This study was designed to determine whether various techniques for achieving rectangular collimation generate different numbers and types of errors and remakes and to determine whether operator skill level influences errors and remakes. Eighteen students exposed full-mouth series of radiographs on manikins with the use of six techniques. The students were grouped according to skill level. The radiographs were evaluated for errors and remakes resulting from errors in the following categories: cone cutting, vertical angulation, and film placement. Significant differences were found among the techniques in cone cutting errors and remakes, vertical angulation errors and remakes, and total errors and remakes. Operator skill did not appear to influence the number or types of errors or remakes generated. Rectangular collimation techniques produced more errors than did the round collimation techniques. However, only one rectangular collimation technique generated significantly more remakes than the other techniques

Methods for Estimation of Radiation Risk in Epidemiological Studies Accounting for Classical and Berkson Errors in Doses

KAUST Repository

Kukush, Alexander

2011-01-16

With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

Methods for estimation of radiation risk in epidemiological studies accounting for classical and Berkson errors in doses.

Science.gov (United States)

Kukush, Alexander; Shklyar, Sergiy; Masiuk, Sergii; Likhtarov, Illya; Kovgan, Lina; Carroll, Raymond J; Bouville, Andre

2011-02-16

With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

Errors in laboratory medicine: practical lessons to improve patient safety.

Science.gov (United States)

Howanitz, Peter J

2005-10-01

Patient safety is influenced by the frequency and seriousness of errors that occur in the health care system. Error rates in laboratory practices are collected routinely for a variety of performance measures in all clinical pathology laboratories in the United States, but a list of critical performance measures has not yet been recommended. The most extensive databases describing error rates in pathology were developed and are maintained by the College of American Pathologists (CAP). These databases include the CAP's Q-Probes and Q-Tracks programs, which provide information on error rates from more than 130 interlaboratory studies. To define critical performance measures in laboratory medicine, describe error rates of these measures, and provide suggestions to decrease these errors, thereby ultimately improving patient safety. A review of experiences from Q-Probes and Q-Tracks studies supplemented with other studies cited in the literature. Q-Probes studies are carried out as time-limited studies lasting 1 to 4 months and have been conducted since 1989. In contrast, Q-Tracks investigations are ongoing studies performed on a yearly basis and have been conducted only since 1998. Participants from institutions throughout the world simultaneously conducted these studies according to specified scientific designs. The CAP has collected and summarized data for participants about these performance measures, including the significance of errors, the magnitude of error rates, tactics for error reduction, and willingness to implement each of these performance measures. A list of recommended performance measures, the frequency of errors when these performance measures were studied, and suggestions to improve patient safety by reducing these errors. Error rates for preanalytic and postanalytic performance measures were higher than for analytic measures. Eight performance measures were identified, including customer satisfaction, test turnaround times, patient identification

Report from LHC MDs 1391 and 1483: Tests of new methods for study of nonlinear errors in the LHC experimental insertions

CERN Document Server

Maclean, Ewen Hamish; Fuchsberger, Kajetan; Giovannozzi, Massimo; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

2017-01-01

Nonlinear errors in experimental insertions can pose a significant challenge to the operability of low-β∗ colliders. Previously such errors in the LHC have been studied via their feed-down to tune and coupling under the influence of the nominal crossing angle bumps. This method has proved useful in validating various components of the magnetic model. To understand and correct those errors where significant discrepancies exist with the magnetic model however, will require further development of this technique, in addition to the application of novel methods. In 2016 studies were performed to test new methods for the study of the IR-nonlinear errors.

Team errors: definition and taxonomy

International Nuclear Information System (INIS)

Sasou, Kunihide; Reason, James

1999-01-01

In error analysis or error management, the focus is usually upon individuals who have made errors. In large complex systems, however, most people work in teams or groups. Considering this working environment, insufficient emphasis has been given to 'team errors'. This paper discusses the definition of team errors and its taxonomy. These notions are also applied to events that have occurred in the nuclear power industry, aviation industry and shipping industry. The paper also discusses the relations between team errors and Performance Shaping Factors (PSFs). As a result, the proposed definition and taxonomy are found to be useful in categorizing team errors. The analysis also reveals that deficiencies in communication, resource/task management, excessive authority gradient, excessive professional courtesy will cause team errors. Handling human errors as team errors provides an opportunity to reduce human errors

Medication administration errors in Eastern Saudi Arabia

International Nuclear Information System (INIS)

Mir Sadat-Ali

2010-01-01

To assess the prevalence and characteristics of medication errors (ME) in patients admitted to King Fahd University Hospital, Alkhobar, Kingdom of Saudi Arabia. Medication errors are documented by the nurses and physicians standard reporting forms (Hospital Based Incident Report). The study was carried out in King Fahd University Hospital, Alkhobar, Kingdom of Saudi Arabia and all the incident reports were collected during the period from January 2008 to December 2009. The incident reports were analyzed for age, gender, nationality, nursing unit, and time where ME was reported. The data were analyzed and the statistical significance differences between groups were determined by Student's t-test, and p-values of <0.05 using confidence interval of 95% were considered significant. There were 38 ME reported for the study period. The youngest patient was 5 days and the oldest 70 years. There were 31 Saudis, and 7 non-Saudi patients involved. The most common error was missed medication, which was seen in 15 (39.5%) patients. Over 15 (39.5%) of errors occurred in 2 units (pediatric medicine, and obstetrics and gynecology). Nineteen (50%) of the errors occurred during the 3-11 pm shift. Our study shows that the prevalence of ME in our institution is low, in comparison with the world literature. This could be due to under reporting of the errors, and we believe that ME reporting should be made less punitive so that ME can be studied and preventive measures implemented (Author).

Nurses' attitude and intention of medication administration error reporting.

Science.gov (United States)

Hung, Chang-Chiao; Chu, Tsui-Ping; Lee, Bih-O; Hsiao, Chia-Chi

2016-02-01

The Aims of this study were to explore the effects of nurses' attitudes and intentions regarding medication administration error reporting on actual reporting behaviours. Underreporting of medication errors is still a common occurrence. Whether attitude and intention towards medication administration error reporting connect to actual reporting behaviours remain unclear. This study used a cross-sectional design with self-administered questionnaires, and the theory of planned behaviour was used as the framework for this study. A total of 596 staff nurses who worked in general wards and intensive care units in a hospital were invited to participate in this study. The researchers used the instruments measuring nurses' attitude, nurse managers' and co-workers' attitude, report control, and nurses' intention to predict nurses' actual reporting behaviours. Data were collected from September-November 2013. Path analyses were used to examine the hypothesized model. Of the 596 nurses invited to participate, 548 (92%) completed and returned a valid questionnaire. The findings indicated that nurse managers' and co-workers' attitudes are predictors for nurses' attitudes towards medication administration error reporting. Nurses' attitudes also influenced their intention to report medication administration errors; however, no connection was found between intention and actual reporting behaviour. The findings reflected links among colleague perspectives, nurses' attitudes, and intention to report medication administration errors. The researchers suggest that hospitals should increase nurses' awareness and recognition of error occurrence. Regardless of nurse managers' and co-workers' attitudes towards medication administration error reporting, nurses are likely to report medication administration errors if they detect them. Management of medication administration errors should focus on increasing nurses' awareness and recognition of error occurrence. © 2015 John Wiley & Sons Ltd.

A dose error evaluation study for 4D dose calculations

Science.gov (United States)

Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

2014-10-01

Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

Eliminating US hospital medical errors.

Science.gov (United States)

Kumar, Sameer; Steinebach, Marc

2008-01-01

Healthcare costs in the USA have continued to rise steadily since the 1980s. Medical errors are one of the major causes of deaths and injuries of thousands of patients every year, contributing to soaring healthcare costs. The purpose of this study is to examine what has been done to deal with the medical-error problem in the last two decades and present a closed-loop mistake-proof operation system for surgery processes that would likely eliminate preventable medical errors. The design method used is a combination of creating a service blueprint, implementing the six sigma DMAIC cycle, developing cause-and-effect diagrams as well as devising poka-yokes in order to develop a robust surgery operation process for a typical US hospital. In the improve phase of the six sigma DMAIC cycle, a number of poka-yoke techniques are introduced to prevent typical medical errors (identified through cause-and-effect diagrams) that may occur in surgery operation processes in US hospitals. It is the authors' assertion that implementing the new service blueprint along with the poka-yokes, will likely result in the current medical error rate to significantly improve to the six-sigma level. Additionally, designing as many redundancies as possible in the delivery of care will help reduce medical errors. Primary healthcare providers should strongly consider investing in adequate doctor and nurse staffing, and improving their education related to the quality of service delivery to minimize clinical errors. This will lead to an increase in higher fixed costs, especially in the shorter time frame. This paper focuses additional attention needed to make a sound technical and business case for implementing six sigma tools to eliminate medical errors that will enable hospital managers to increase their hospital's profitability in the long run and also ensure patient safety.

Accurate recapture identification for genetic mark–recapture studies with error-tolerant likelihood-based match calling and sample clustering

Science.gov (United States)

Sethi, Suresh; Linden, Daniel; Wenburg, John; Lewis, Cara; Lemons, Patrick R.; Fuller, Angela K.; Hare, Matthew P.

2016-01-01

Error-tolerant likelihood-based match calling presents a promising technique to accurately identify recapture events in genetic mark–recapture studies by combining probabilities of latent genotypes and probabilities of observed genotypes, which may contain genotyping errors. Combined with clustering algorithms to group samples into sets of recaptures based upon pairwise match calls, these tools can be used to reconstruct accurate capture histories for mark–recapture modelling. Here, we assess the performance of a recently introduced error-tolerant likelihood-based match-calling model and sample clustering algorithm for genetic mark–recapture studies. We assessed both biallelic (i.e. single nucleotide polymorphisms; SNP) and multiallelic (i.e. microsatellite; MSAT) markers using a combination of simulation analyses and case study data on Pacific walrus (Odobenus rosmarus divergens) and fishers (Pekania pennanti). A novel two-stage clustering approach is demonstrated for genetic mark–recapture applications. First, repeat captures within a sampling occasion are identified. Subsequently, recaptures across sampling occasions are identified. The likelihood-based matching protocol performed well in simulation trials, demonstrating utility for use in a wide range of genetic mark–recapture studies. Moderately sized SNP (64+) and MSAT (10–15) panels produced accurate match calls for recaptures and accurate non-match calls for samples from closely related individuals in the face of low to moderate genotyping error. Furthermore, matching performance remained stable or increased as the number of genetic markers increased, genotyping error notwithstanding.

Video Error Correction Using Steganography

Science.gov (United States)

Robie, David L.; Mersereau, Russell M.

2002-12-01

The transmission of any data is always subject to corruption due to errors, but video transmission, because of its real time nature must deal with these errors without retransmission of the corrupted data. The error can be handled using forward error correction in the encoder or error concealment techniques in the decoder. This MPEG-2 compliant codec uses data hiding to transmit error correction information and several error concealment techniques in the decoder. The decoder resynchronizes more quickly with fewer errors than traditional resynchronization techniques. It also allows for perfect recovery of differentially encoded DCT-DC components and motion vectors. This provides for a much higher quality picture in an error-prone environment while creating an almost imperceptible degradation of the picture in an error-free environment.

An empirical study on the human error recovery failure probability when using soft controls in NPP advanced MCRs

International Nuclear Information System (INIS)

Jang, Inseok; Kim, Ar Ryum; Jung, Wondea; Seong, Poong Hyun

2014-01-01

Highlights: • Many researchers have tried to understand human recovery process or step. • Modeling human recovery process is not sufficient to be applied to HRA. • The operation environment of MCRs in NPPs has changed by adopting new HSIs. • Recovery failure probability in a soft control operation environment is investigated. • Recovery failure probability here would be important evidence for expert judgment. - Abstract: It is well known that probabilistic safety assessments (PSAs) today consider not just hardware failures and environmental events that can impact upon risk, but also human error contributions. Consequently, the focus on reliability and performance management has been on the prevention of human errors and failures rather than the recovery of human errors. However, the recovery of human errors is as important as the prevention of human errors and failures for the safe operation of nuclear power plants (NPPs). For this reason, many researchers have tried to find a human recovery process or step. However, modeling the human recovery process is not sufficient enough to be applied to human reliability analysis (HRA), which requires human error and recovery probabilities. In this study, therefore, human error recovery failure probabilities based on predefined human error modes were investigated by conducting experiments in the operation mockup of advanced/digital main control rooms (MCRs) in NPPs. To this end, 48 subjects majoring in nuclear engineering participated in the experiments. In the experiments, using the developed accident scenario based on tasks from the standard post trip action (SPTA), the steam generator tube rupture (SGTR), and predominant soft control tasks, which are derived from the loss of coolant accident (LOCA) and the excess steam demand event (ESDE), all error detection and recovery data based on human error modes were checked with the performance sheet and the statistical analysis of error recovery/detection was then

Normalization of Deviation: Quotation Error in Human Factors.

Science.gov (United States)

Lock, Jordan; Bearman, Chris

2018-05-01

Objective The objective of this paper is to examine quotation error in human factors. Background Science progresses through building on the work of previous research. This requires accurate quotation. Quotation error has a number of adverse consequences: loss of credibility, loss of confidence in the journal, and a flawed basis for academic debate and scientific progress. Quotation error has been observed in a number of domains, including marine biology and medicine, but there has been little or no previous study of this form of error in human factors, a domain that specializes in the causes and management of error. Methods A study was conducted examining quotation accuracy of 187 extracts from 118 published articles that cited a control article (Vaughan's 1996 book: The Challenger Launch Decision: Risky Technology, Culture, and Deviance at NASA). Results Of extracts studied, 12.8% ( n = 24) were classed as inaccurate, with 87.2% ( n = 163) being classed as accurate. A second dimension of agreement was examined with 96.3% ( n = 180) agreeing with the control article and only 3.7% ( n = 7) disagreeing. The categories of accuracy and agreement form a two by two matrix. Conclusion Rather than simply blaming individuals for quotation error, systemic factors should also be considered. Vaughan's theory, normalization of deviance, is one systemic theory that can account for quotation error. Application Quotation error is occurring in human factors and should receive more attention. According to Vaughan's theory, the normal everyday systems that promote scholarship may also allow mistakes, mishaps, and quotation error to occur.

Rotational error in path integration: encoding and execution errors in angle reproduction.

Science.gov (United States)

Chrastil, Elizabeth R; Warren, William H

2017-06-01

Path integration is fundamental to human navigation. When a navigator leaves home on a complex outbound path, they are able to keep track of their approximate position and orientation and return to their starting location on a direct homebound path. However, there are several sources of error during path integration. Previous research has focused almost exclusively on encoding error-the error in registering the outbound path in memory. Here, we also consider execution error-the error in the response, such as turning and walking a homebound trajectory. In two experiments conducted in ambulatory virtual environments, we examined the contribution of execution error to the rotational component of path integration using angle reproduction tasks. In the reproduction tasks, participants rotated once and then rotated again to face the original direction, either reproducing the initial turn or turning through the supplementary angle. One outstanding difficulty in disentangling encoding and execution error during a typical angle reproduction task is that as the encoding angle increases, so does the required response angle. In Experiment 1, we dissociated these two variables by asking participants to report each encoding angle using two different responses: by turning to walk on a path parallel to the initial facing direction in the same (reproduction) or opposite (supplementary angle) direction. In Experiment 2, participants reported the encoding angle by turning both rightward and leftward onto a path parallel to the initial facing direction, over a larger range of angles. The results suggest that execution error, not encoding error, is the predominant source of error in angular path integration. These findings also imply that the path integrator uses an intrinsic (action-scaled) rather than an extrinsic (objective) metric.

A STUDY OF ERRORS IN THE THIRD SINGULAR PRONOUNS OF SIMPLE PRESENT TENSE BY USING INTERLANGUAGE ANALYSIS AS AN APPROACH. A CASE STUDY

Directory of Open Access Journals (Sweden)

Salmon Pandarangga

2015-03-01

Full Text Available The purpose of this study is to analyze factors contributing to errors made in learning English as a target language (TL. Employing a case study research, the participant was interviewed for approximately 30 minutes about daily activities and experiences in learning English. This research focuses in analysing the participant‟s use of third singular pronoun in simple present tense. The findings revealed that errors made by TL learners are mainly influenced by some factorsrelated to their TL‟s and native language‟s (NL knowledge, systems and rules. These factors are coexisted and interconnected in TL learners‟ minds. This is against Robert Lado‟s argument which mentioned that learner made errors in TL learning because of the interference from NL. The study provides pedagogical implications that TL teachers should perceive errors made by the learners as a sign of language learning and development; therefore they should not be discouraged to learn. Also, TL teachers should be aware of their very important roles to help, to guide and to lead the learners‟ progress in learning the TL. The future subsequent studies should consider of involving more sample size over a longer period of time as to obtain to a more generalized finding.

Energy efficiency of error correction on wireless systems

NARCIS (Netherlands)

Havinga, Paul J.M.

1999-01-01

Since high error rates are inevitable to the wireless environment, energy-efficient error-control is an important issue for mobile computing systems. We have studied the energy efficiency of two different error correction mechanisms and have measured the efficiency of an implementation in software.

Beyond hypercorrection: remembering corrective feedback for low-confidence errors.

Science.gov (United States)

Griffiths, Lauren; Higham, Philip A

2018-02-01

Correcting errors based on corrective feedback is essential to successful learning. Previous studies have found that corrections to high-confidence errors are better remembered than low-confidence errors (the hypercorrection effect). The aim of this study was to investigate whether corrections to low-confidence errors can also be successfully retained in some cases. Participants completed an initial multiple-choice test consisting of control, trick and easy general-knowledge questions, rated their confidence after answering each question, and then received immediate corrective feedback. After a short delay, they were given a cued-recall test consisting of the same questions. In two experiments, we found high-confidence errors to control questions were better corrected on the second test compared to low-confidence errors - the typical hypercorrection effect. However, low-confidence errors to trick questions were just as likely to be corrected as high-confidence errors. Most surprisingly, we found that memory for the feedback and original responses, not confidence or surprise, were significant predictors of error correction. We conclude that for some types of material, there is an effortful process of elaboration and problem solving prior to making low-confidence errors that facilitates memory of corrective feedback.

Spacecraft and propulsion technician error

Science.gov (United States)

Schultz, Daniel Clyde

Commercial aviation and commercial space similarly launch, fly, and land passenger vehicles. Unlike aviation, the U.S. government has not established maintenance policies for commercial space. This study conducted a mixed methods review of 610 U.S. space launches from 1984 through 2011, which included 31 failures. An analysis of the failure causal factors showed that human error accounted for 76% of those failures, which included workmanship error accounting for 29% of the failures. With the imminent future of commercial space travel, the increased potential for the loss of human life demands that changes be made to the standardized procedures, training, and certification to reduce human error and failure rates. Several recommendations were made by this study to the FAA's Office of Commercial Space Transportation, space launch vehicle operators, and maintenance technician schools in an effort to increase the safety of the space transportation passengers.

Video Error Correction Using Steganography

Directory of Open Access Journals (Sweden)

Robie David L

2002-01-01

Full Text Available The transmission of any data is always subject to corruption due to errors, but video transmission, because of its real time nature must deal with these errors without retransmission of the corrupted data. The error can be handled using forward error correction in the encoder or error concealment techniques in the decoder. This MPEG-2 compliant codec uses data hiding to transmit error correction information and several error concealment techniques in the decoder. The decoder resynchronizes more quickly with fewer errors than traditional resynchronization techniques. It also allows for perfect recovery of differentially encoded DCT-DC components and motion vectors. This provides for a much higher quality picture in an error-prone environment while creating an almost imperceptible degradation of the picture in an error-free environment.

Temperature-dependent errors in nuclear lattice simulations

International Nuclear Information System (INIS)

Lee, Dean; Thomson, Richard

2007-01-01

We study the temperature dependence of discretization errors in nuclear lattice simulations. We find that for systems with strong attractive interactions the predominant error arises from the breaking of Galilean invariance. We propose a local 'well-tempered' lattice action which eliminates much of this error. The well-tempered action can be readily implemented in lattice simulations for nuclear systems as well as cold atomic Fermi systems

Part two: Error propagation

International Nuclear Information System (INIS)

Picard, R.R.

1989-01-01

Topics covered in this chapter include a discussion of exact results as related to nuclear materials management and accounting in nuclear facilities; propagation of error for a single measured value; propagation of error for several measured values; error propagation for materials balances; and an application of error propagation to an example of uranium hexafluoride conversion process

Error monitoring and empathy: Explorations within a neurophysiological context.

Science.gov (United States)

Amiruddin, Azhani; Fueggle, Simone N; Nguyen, An T; Gignac, Gilles E; Clunies-Ross, Karen L; Fox, Allison M

2017-06-01

Past literature has proposed that empathy consists of two components: cognitive and affective empathy. Error monitoring mechanisms indexed by the error-related negativity (ERN) have been associated with empathy. Studies have found that a larger ERN is associated with higher levels of empathy. We aimed to expand upon previous work by investigating how error monitoring relates to the independent theoretical domains of cognitive and affective empathy. Study 1 (N = 24) explored the relationship between error monitoring mechanisms and subcomponents of empathy using the Questionnaire of Cognitive and Affective Empathy and found no relationship. Study 2 (N = 38) explored the relationship between the error monitoring mechanisms and overall empathy. Contrary to past findings, there was no evidence to support a relationship between error monitoring mechanisms and scores on empathy measures. A subsequent meta-analysis (Study 3, N = 125) summarizing the relationship across previously published studies together with the two studies reported in the current paper indicated that overall there was no significant association between ERN and empathy and that there was significant heterogeneity across studies. Future investigations exploring the potential variables that may moderate these relationships are discussed. © 2017 Society for Psychophysiological Research.

Dual processing and diagnostic errors.

Science.gov (United States)

Norman, Geoff

2009-09-01

In this paper, I review evidence from two theories in psychology relevant to diagnosis and diagnostic errors. "Dual Process" theories of thinking, frequently mentioned with respect to diagnostic error, propose that categorization decisions can be made with either a fast, unconscious, contextual process called System 1 or a slow, analytical, conscious, and conceptual process, called System 2. Exemplar theories of categorization propose that many category decisions in everyday life are made by unconscious matching to a particular example in memory, and these remain available and retrievable individually. I then review studies of clinical reasoning based on these theories, and show that the two processes are equally effective; System 1, despite its reliance in idiosyncratic, individual experience, is no more prone to cognitive bias or diagnostic error than System 2. Further, I review evidence that instructions directed at encouraging the clinician to explicitly use both strategies can lead to consistent reduction in error rates.

On the Correspondence between Mean Forecast Errors and Climate Errors in CMIP5 Models

Energy Technology Data Exchange (ETDEWEB)

Ma, H. -Y.; Xie, S.; Klein, S. A.; Williams, K. D.; Boyle, J. S.; Bony, S.; Douville, H.; Fermepin, S.; Medeiros, B.; Tyteca, S.; Watanabe, M.; Williamson, D.

2014-02-01

The present study examines the correspondence between short- and long-term systematic errors in five atmospheric models by comparing the 16 five-day hindcast ensembles from the Transpose Atmospheric Model Intercomparison Project II (Transpose-AMIP II) for July–August 2009 (short term) to the climate simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5) and AMIP for the June–August mean conditions of the years of 1979–2008 (long term). Because the short-term hindcasts were conducted with identical climate models used in the CMIP5/AMIP simulations, one can diagnose over what time scale systematic errors in these climate simulations develop, thus yielding insights into their origin through a seamless modeling approach. The analysis suggests that most systematic errors of precipitation, clouds, and radiation processes in the long-term climate runs are present by day 5 in ensemble average hindcasts in all models. Errors typically saturate after few days of hindcasts with amplitudes comparable to the climate errors, and the impacts of initial conditions on the simulated ensemble mean errors are relatively small. This robust bias correspondence suggests that these systematic errors across different models likely are initiated by model parameterizations since the atmospheric large-scale states remain close to observations in the first 2–3 days. However, biases associated with model physics can have impacts on the large-scale states by day 5, such as zonal winds, 2-m temperature, and sea level pressure, and the analysis further indicates a good correspondence between short- and long-term biases for these large-scale states. Therefore, improving individual model parameterizations in the hindcast mode could lead to the improvement of most climate models in simulating their climate mean state and potentially their future projections.

Prediction-error of Prediction Error (PPE)-based Reversible Data Hiding

OpenAIRE

Wu, Han-Zhou; Wang, Hong-Xia; Shi, Yun-Qing

2016-01-01

This paper presents a novel reversible data hiding (RDH) algorithm for gray-scaled images, in which the prediction-error of prediction error (PPE) of a pixel is used to carry the secret data. In the proposed method, the pixels to be embedded are firstly predicted with their neighboring pixels to obtain the corresponding prediction errors (PEs). Then, by exploiting the PEs of the neighboring pixels, the prediction of the PEs of the pixels can be determined. And, a sorting technique based on th...

Error Analysis for Arithmetic Word Problems--A Case Study of Primary Three Students in One Singapore School

Science.gov (United States)

Cheng, Lu Pien

2015-01-01

In this study, ways in which 9-year old students from one Singapore school solved 1-step and 2-step word problems based on the three semantic structures were examined. The students' work and diagrams provided insights into the range of errors in word problem solving for 1- step and 2-step word problems. In particular, the errors provided some…

Barriers to Medical Error Reporting for Physicians and Nurses.

Science.gov (United States)

Soydemir, Dilek; Seren Intepeler, Seyda; Mert, Hatice

2017-10-01

The purpose of the study was to determine what barriers to error reporting exist for physicians and nurses. The study, of descriptive qualitative design, was conducted with physicians and nurses working at a training and research hospital. In-depth interviews were held with eight physicians and 15 nurses, a total of 23 participants. Physicians and nurses do not choose to report medical errors that they experience or witness. When barriers to error reporting were examined, it was seen that there were four main themes involved: fear, the attitude of administration, barriers related to the system, and the employees' perceptions of error. It is important in terms of preventing medical errors to identify the barriers that keep physicians and nurses from reporting errors.

Simulation study on heterogeneous variance adjustment for observations with different measurement error variance

DEFF Research Database (Denmark)

Pitkänen, Timo; Mäntysaari, Esa A; Nielsen, Ulrik Sander

2013-01-01

of variance correction is developed for the same observations. As automated milking systems are becoming more popular the current evaluation model needs to be enhanced to account for the different measurement error variances of observations from automated milking systems. In this simulation study different...... models and different approaches to account for heterogeneous variance when observations have different measurement error variances were investigated. Based on the results we propose to upgrade the currently applied models and to calibrate the heterogeneous variance adjustment method to yield same genetic......The Nordic Holstein yield evaluation model describes all available milk, protein and fat test-day yields from Denmark, Finland and Sweden. In its current form all variance components are estimated from observations recorded under conventional milking systems. Also the model for heterogeneity...

Errors in the administration of intravenous medication in Brazilian hospitals.

Science.gov (United States)

Anselmi, Maria Luiza; Peduzzi, Marina; Dos Santos, Claudia Benedita

2007-10-01

To verify the frequency of errors in the preparation and administration of intravenous medication in three Brazilian hospitals in the State of Bahia. The administration of intravenous medications constitutes a central activity in Brazilian nursing. Errors in performing this activity may result in irreparable damage to patients and may compromise the quality of care. Cross-sectional study, conducted in three hospitals in the State of Bahia, Brazil. Direct observation of the nursing staff (nurse technicians, auxiliary nurses and nurse attendants), preparing and administering intravenous medication. When preparing medication, wrong patient error did not occur in any of the three hospitals, whereas omission dose was the most frequent error in all study sites. When administering medication, the most frequent errors in the three hospitals were wrong dose and omission dose. The rates of error found are considered low compared with similar studies. The most frequent types of errors were wrong dose and omission dose. The hospitals studied showed different results with the smallest rates of errors occurring in hospital 1 that presented the best working conditions. Relevance to clinical practice. Studies such as this one have the potential to improve the quality of care.

Medical Error Types and Causes Made by Nurses in Turkey

Directory of Open Access Journals (Sweden)

Dilek Kucuk Alemdar

2013-06-01

Full Text Available AIM: This study was carried out as a descriptive study in order to determine types, causes and prevalence of medical errors made by nurses in Turkey. METHOD: Seventy eight (78 nurses who have worked in a randomly selected hospital from five hospitals in Giresun city centre were enrolled in the study. The data was collected by the researchers using the ‘Information Form for Nurses’ and ‘Medical Error Form’. The Medical Error Form consists of 2 parts and 40 items including types and causes of medical errors. Nurses’ socio-demographic variables, medical error types and causes were evaluated using the percentage distribution and mean. RESULTS: The mean age of the nurses was 25.5 years, with a standard deviation 6.03 years. 50% of the nurses graduated health professional high school in the study. 53.8% of the nurses are single, 63.1% worked between 1-5 years, 71.8% day and night shifts and 42.3% in medical clinics. The common types of medical errors were hospital infection rate of 15.4%, diagnostic errors 12.8%, needle or cutting tool injuries and problems related to drug usage which has side effects 10.3%. In the study 38.5% of the nurses reported that they thought the cause of medical error highly was tiredness, 36.4% increased workload and 34.6% long working hours. CONCLUSION: As a result of the present study, nurses mentioned hospital infection, diagnostic errors, needle or cutting tool injuries as the most common medical errors and fatigue, over work load and long working hours as the most common medical error reasons. [TAF Prev Med Bull 2013; 12(3.000: 307-314

Preventing Medication Error Based on Knowledge Management Against Adverse Event

OpenAIRE

Hastuti, Apriyani Puji; Nursalam, Nursalam; Triharini, Mira

2017-01-01

Introductions: Medication error is one of many types of errors that could decrease the quality and safety of healthcare. Increasing number of adverse events (AE) reflects the number of medication errors. This study aimed to develop a model of medication error prevention based on knowledge management. This model is expected to improve knowledge and skill of nurses to prevent medication error which is characterized by the decrease of adverse events (AE). Methods: This study consisted of two sta...

Medication administration errors in an intensive care unit in Ethiopia

Directory of Open Access Journals (Sweden)

Agalu Asrat

2012-05-01

Full Text Available Abstract Background Medication administration errors in patient care have been shown to be frequent and serious. Such errors are particularly prevalent in highly technical specialties such as the intensive care unit (ICU. In Ethiopia, the prevalence of medication administration errors in the ICU is not studied. Objective To assess medication administration errors in the intensive care unit of Jimma University Specialized Hospital (JUSH, Southwest Ethiopia. Methods Prospective observation based cross-sectional study was conducted in the ICU of JUSH from February 7 to March 24, 2011. All medication interventions administered by the nurses to all patients admitted to the ICU during the study period were included in the study. Data were collected by directly observing drug administration by the nurses supplemented with review of medication charts. Data was edited, coded and entered in to SPSS for windows version 16.0. Descriptive statistics was used to measure the magnitude and type of the problem under study. Results Prevalence of medication administration errors in the ICU of JUSH was 621 (51.8%. Common administration errors were attributed to wrong timing (30.3%, omission due to unavailability (29.0% and missed doses (18.3% among others. Errors associated with antibiotics took the lion's share in medication administration errors (36.7%. Conclusion Medication errors at the administration phase were highly prevalent in the ICU of Jimma University Specialized Hospital. Supervision to the nurses administering medications by more experienced ICU nurses or other relevant professionals in regular intervals is helpful in ensuring that medication errors don’t occur as frequently as observed in this study.

Modelling and mitigation of soft-errors in CMOS processors

NARCIS (Netherlands)

Rohani, A.

2014-01-01

The topic of this thesis is about soft-errors in digital systems. Different aspects of soft-errors have been addressed here, including an accurate simulation model to emulate soft-errors in a gate-level net list, a simulation framework to study the impact of soft-errors in a VHDL design and an

Medication errors of nurses and factors in refusal to report medication errors among nurses in a teaching medical center of iran in 2012.

Science.gov (United States)

Mostafaei, Davoud; Barati Marnani, Ahmad; Mosavi Esfahani, Haleh; Estebsari, Fatemeh; Shahzaidi, Shiva; Jamshidi, Ensiyeh; Aghamiri, Seyed Samad

2014-10-01

About one third of unwanted reported medication consequences are due to medication errors, resulting in one-fifth of hospital injuries. The aim of this study was determined formal and informal medication errors of nurses and the level of importance of factors in refusal to report medication errors among nurses. The cross-sectional study was done on the nursing staff of Shohada Tajrish Hospital, Tehran, Iran in 2012. The data was gathered through a questionnaire, made by the researchers. The questionnaires' face and content validity was confirmed by experts and for measuring its reliability test-retest was used. The data was analyzed by descriptive statistics. We used SPSS for related statistical analyses. The most important factors in refusal to report medication errors respectively were: lack of medication error recording and reporting system in the hospital (3.3%), non-significant error reporting to hospital authorities and lack of appropriate feedback (3.1%), and lack of a clear definition for a medication error (3%). There were both formal and informal reporting of medication errors in this study. Factors pertaining to management in hospitals as well as the fear of the consequences of reporting are two broad fields among the factors that make nurses not report their medication errors. In this regard, providing enough education to nurses, boosting the job security for nurses, management support and revising related processes and definitions are some factors that can help decreasing medication errors and increasing their report in case of occurrence.

Monte Carlo simulation of expert judgments on human errors in chemical analysis--a case study of ICP-MS.

Science.gov (United States)

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.

Random and correlated errors in gold standards used in nutritional epidemiology: implications for validation studies

Science.gov (United States)

The measurement error correction de-attenuation factor was estimated from two studies using recovery biomarkers. One study, the Observing Protein and Energy Nutrition (OPEN), was unable to adequately account for within-person variation in protein and energy intake estimated by recovery biomarkers, ...

Refractive error, ocular biometry, and lens opalescence in an adult population: the Los Angeles Latino Eye Study.

Science.gov (United States)

Shufelt, Chrisandra; Fraser-Bell, Samantha; Ying-Lai, Mei; Torres, Mina; Varma, Rohit

2005-12-01

To characterize age- and gender-related differences in refractive error, ocular biometry, and lens opalescence (NOP) in a population-based sample of adult Latinos. Also assessed were the determinants of age-related refractive differences. Participants in the Los Angeles Latino Eye Study (LALES), a population-based study of Latinos aged 40 years and more, underwent an ophthalmic examination, including ultrasonic measurements of axial length (AL), vitreous chamber depth (VCD), anterior chamber depth (ACD), lens thickness (LT), and noncycloplegic automated and subjective refraction. Corneal curvature/power (CP) was measured using an autorefractor. NOP was graded at the slit lamp by an ophthalmologist using the Lens Opacity Classification System II. Age- and gender-related differences were calculated. Multiple regression models were used to identify the determinants of age-related refractive differences. Of the 6357 LALES participants, 5588 phakic individuals with biometric data were included in this analysis. Older individuals had shallower ACDs, thicker lenses, more NOP, and more hyperopia compared to younger individuals (P or = 0.05). Women had significantly shorter AL, shallower ACD and VCD, than did men (P < or = 0.01). The strongest determinants of refractive error were AL (primarily VCD) and CP. NOP was a small but significant determinant of refractive error in older individuals. Age- and gender-related differences in ocular biometric, refractive error, and NOP measurements are present in adult Latinos. While the relative contribution of NOP in determining refractive error is small, it is greater in older persons compared to younger individuals.

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

Science.gov (United States)

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

2011-03-01

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

The Applicability of Standard Error of Measurement and Minimal Detectable Change to Motor Learning Research-A Behavioral Study.

Science.gov (United States)

Furlan, Leonardo; Sterr, Annette

2018-01-01

Motor learning studies face the challenge of differentiating between real changes in performance and random measurement error. While the traditional p -value-based analyses of difference (e.g., t -tests, ANOVAs) provide information on the statistical significance of a reported change in performance scores, they do not inform as to the likely cause or origin of that change, that is, the contribution of both real modifications in performance and random measurement error to the reported change. One way of differentiating between real change and random measurement error is through the utilization of the statistics of standard error of measurement (SEM) and minimal detectable change (MDC). SEM is estimated from the standard deviation of a sample of scores at baseline and a test-retest reliability index of the measurement instrument or test employed. MDC, in turn, is estimated from SEM and a degree of confidence, usually 95%. The MDC value might be regarded as the minimum amount of change that needs to be observed for it to be considered a real change, or a change to which the contribution of real modifications in performance is likely to be greater than that of random measurement error. A computer-based motor task was designed to illustrate the applicability of SEM and MDC to motor learning research. Two studies were conducted with healthy participants. Study 1 assessed the test-retest reliability of the task and Study 2 consisted in a typical motor learning study, where participants practiced the task for five consecutive days. In Study 2, the data were analyzed with a traditional p -value-based analysis of difference (ANOVA) and also with SEM and MDC. The findings showed good test-retest reliability for the task and that the p -value-based analysis alone identified statistically significant improvements in performance over time even when the observed changes could in fact have been smaller than the MDC and thereby caused mostly by random measurement error, as opposed

Learning a locomotor task: with or without errors?

Science.gov (United States)

Marchal-Crespo, Laura; Schneider, Jasmin; Jaeger, Lukas; Riener, Robert

2014-03-04

Robotic haptic guidance is the most commonly used robotic training strategy to reduce performance errors while training. However, research on motor learning has emphasized that errors are a fundamental neural signal that drive motor adaptation. Thus, researchers have proposed robotic therapy algorithms that amplify movement errors rather than decrease them. However, to date, no study has analyzed with precision which training strategy is the most appropriate to learn an especially simple task. In this study, the impact of robotic training strategies that amplify or reduce errors on muscle activation and motor learning of a simple locomotor task was investigated in twenty two healthy subjects. The experiment was conducted with the MAgnetic Resonance COmpatible Stepper (MARCOS) a special robotic device developed for investigations in the MR scanner. The robot moved the dominant leg passively and the subject was requested to actively synchronize the non-dominant leg to achieve an alternating stepping-like movement. Learning with four different training strategies that reduce or amplify errors was evaluated: (i) Haptic guidance: errors were eliminated by passively moving the limbs, (ii) No guidance: no robot disturbances were presented, (iii) Error amplification: existing errors were amplified with repulsive forces, (iv) Noise disturbance: errors were evoked intentionally with a randomly-varying force disturbance on top of the no guidance strategy. Additionally, the activation of four lower limb muscles was measured by the means of surface electromyography (EMG). Strategies that reduce or do not amplify errors limit muscle activation during training and result in poor learning gains. Adding random disturbing forces during training seems to increase attention, and therefore improve motor learning. Error amplification seems to be the most suitable strategy for initially less skilled subjects, perhaps because subjects could better detect their errors and correct them

ERM model analysis for adaptation to hydrological model errors

Science.gov (United States)

Baymani-Nezhad, M.; Han, D.

2018-05-01

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

Can human error theory explain non-adherence?

Science.gov (United States)

Barber, Nick; Safdar, A; Franklin, Bryoney D

2005-08-01

To apply human error theory to explain non-adherence and examine how well it fits. Patients who were taking chronic medication were telephoned and asked whether they had been adhering to their medicine, and if not the reasons were explored and analysed according to a human error theory. Of 105 patients, 87 were contacted by telephone and they took part in the study. Forty-two recalled being non-adherent, 17 of them in the last 7 days; 11 of the 42 were intentionally non-adherent. The errors could be described by human error theory, and it explained unintentional non-adherence well, however, the application of 'rules' was difficult when considering mistakes. The consideration of error producing conditions and latent failures also revealed useful contributing factors. Human error theory offers a new and valuable way of understanding non-adherence, and could inform interventions. However, the theory needs further development to explain intentional non-adherence.

Medication Errors in the Southeast Asian Countries: A Systematic Review.

Directory of Open Access Journals (Sweden)

Shahrzad Salmasi

Full Text Available Medication error (ME is a worldwide issue, but most studies on ME have been undertaken in developed countries and very little is known about ME in Southeast Asian countries. This study aimed systematically to identify and review research done on ME in Southeast Asian countries in order to identify common types of ME and estimate its prevalence in this region.The literature relating to MEs in Southeast Asian countries was systematically reviewed in December 2014 by using; Embase, Medline, Pubmed, ProQuest Central and the CINAHL. Inclusion criteria were studies (in any languages that investigated the incidence and the contributing factors of ME in patients of all ages.The 17 included studies reported data from six of the eleven Southeast Asian countries: five studies in Singapore, four in Malaysia, three in Thailand, three in Vietnam, one in the Philippines and one in Indonesia. There was no data on MEs in Brunei, Laos, Cambodia, Myanmar and Timor. Of the seventeen included studies, eleven measured administration errors, four focused on prescribing errors, three were done on preparation errors, three on dispensing errors and two on transcribing errors. There was only one study of reconciliation error. Three studies were interventional.The most frequently reported types of administration error were incorrect time, omission error and incorrect dose. Staff shortages, and hence heavy workload for nurses, doctor/nurse distraction, and misinterpretation of the prescription/medication chart, were identified as contributing factors of ME. There is a serious lack of studies on this topic in this region which needs to be addressed if the issue of ME is to be fully understood and addressed.

Systematic Analysis of Video Data from Different Human-Robot Interaction Studies: A Categorisation of Social Signals During Error Situations

OpenAIRE

Manuel eGiuliani; Nicole eMirnig; Gerald eStollnberger; Susanne eStadler; Roland eBuchner; Manfred eTscheligi

2015-01-01

Human?robot interactions are often affected by error situations that are caused by either the robot or the human. Therefore, robots would profit from the ability to recognize when error situations occur. We investigated the verbal and non-verbal social signals that humans show when error situations occur in human?robot interaction experiments. For that, we analyzed 201 videos of five human?robot interaction user studies with varying tasks from four independent projects. The analysis shows tha...

Subject-verb agreement: Error production by Tourism undergraduate students

Directory of Open Access Journals (Sweden)

Ana Paula Correia

2014-11-01

Full Text Available The aim of this paper, which is part of a more extensive research on verb tense errors, is to investigate the subject-verb agreement errors in the simple present in the texts of a group of Tourism undergraduate students. Based on the concept of interlanguage and following the error analysis model, this descriptive non-experimental study applies qualitative and quantitative procedures. Three types of instruments were used to collect data: a sociolinguistic questionnaire (to define the learners’ profile; the Dialang test (to establish their proficiency level in English; and our own learner corpus (140 texts. Errors were identified and classified by an expert panel in accordance with a verb error taxonomy developed for this study based on the taxonomy established by the Cambridge Learner Corpus. The Markin software was used to code errors in the corpus and the Wordsmith Tools software to analyze the data. Subject-verb agreement errors and their relation with the learners’ proficiency levels are described.

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.

Errors in Neonatology

OpenAIRE

Antonio Boldrini; Rosa T. Scaramuzzo; Armando Cuttano

2013-01-01

Introduction: Danger and errors are inherent in human activities. In medical practice errors can lean to adverse events for patients. Mass media echo the whole scenario. Methods: We reviewed recent published papers in PubMed database to focus on the evidence and management of errors in medical practice in general and in Neonatology in particular. We compared the results of the literature with our specific experience in Nina Simulation Centre (Pisa, Italy). Results: In Neonatology the main err...

Medication errors in anaesthetic practice: a report of two cases and ...

African Journals Online (AJOL)

EB

2013-09-03

Sep 3, 2013 ... Key words: Medication errors, anaesthetic practice, vigilance, safety .... reports in the Australian Incident Monitoring Study. (AIMS). ... contribute to systems failure and prescription errors were most ... being due to equipment error.17 Previous studies have ... errors reported occurred during day shifts and they.

A Simulation Study on Patient Setup Errors in External Beam Radiotherapy Using an Anthropomorphic 4D Phantom

Directory of Open Access Journals (Sweden)

Payam Samadi Miandoab

2016-12-01

Full Text Available Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate patient geometrical setup using 4-dimensional (4D XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion of dynamic organs, a phantom employs non-uniform rational B-splines (NURBS-based Cardiac-Torso method with spline-based model to generate 4D computed tomography (CT images. First, to generate all the possible roto-translation positions, the 4D CT images were imported to Medical Image Data Examiner (AMIDE. Then, for automatic, real time verification of geometrical setup, an artificial neural network (ANN was proposed to estimate patient displacement, using training sets. Moreover, three external motion markers were synchronized with a patient couch position as reference points. In addition, the technique was validated through simulated activities by using reference 4D CT data acquired from five patients. Results The results indicated that patient geometrical set-up is highly depended on the comprehensiveness of training set. By using ANN model, the average patient setup error in XCAT phantom was reduced from 17.26 mm to 0.50 mm. In addition, in the five real patients, these average errors were decreased from 18.26 mm to 1.48 mm various breathing phases ranging from inhalation to exhalation were taken into account for patient setup. Uncertainty error assessment and different setup errors were obtained from each respiration phase. Conclusion This study proposed a new method for alignment of patient setup error using ANN model. Additionally, our correlation model (ANN could estimate true patient position with less error.

Error Cost Escalation Through the Project Life Cycle

Science.gov (United States)

Stecklein, Jonette M.; Dabney, Jim; Dick, Brandon; Haskins, Bill; Lovell, Randy; Moroney, Gregory

2004-01-01

It is well known that the costs to fix errors increase as the project matures, but how fast do those costs build? A study was performed to determine the relative cost of fixing errors discovered during various phases of a project life cycle. This study used three approaches to determine the relative costs: the bottom-up cost method, the total cost breakdown method, and the top-down hypothetical project method. The approaches and results described in this paper presume development of a hardware/software system having project characteristics similar to those used in the development of a large, complex spacecraft, a military aircraft, or a small communications satellite. The results show the degree to which costs escalate, as errors are discovered and fixed at later and later phases in the project life cycle. If the cost of fixing a requirements error discovered during the requirements phase is defined to be 1 unit, the cost to fix that error if found during the design phase increases to 3 - 8 units; at the manufacturing/build phase, the cost to fix the error is 7 - 16 units; at the integration and test phase, the cost to fix the error becomes 21 - 78 units; and at the operations phase, the cost to fix the requirements error ranged from 29 units to more than 1500 units

Putting a face on medical errors: a patient perspective.

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Kooienga, Sarah; Stewart, Valerie T

2011-01-01

Knowledge of the patient's perspective on medical error is limited. Research efforts have centered on how best to disclose error and how patients desire to have medical error disclosed. On the basis of a qualitative descriptive component of a mixed method study, a purposive sample of 30 community members told their stories of medical error. Their experiences focused on lack of communication, missed communication, or provider's poor interpersonal style of communication, greatly contrasting with the formal definition of error as failure to follow a set standard of care. For these participants, being a patient was more important than error or how an error is disclosed. The patient's understanding of error must be a key aspect of any quality improvement strategy. © 2010 National Association for Healthcare Quality.

A simulation study to quantify the impacts of exposure measurement error on air pollution health risk estimates in copollutant time-series models.

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Dionisio, Kathie L; Chang, Howard H; Baxter, Lisa K

2016-11-25

Exposure measurement error in copollutant epidemiologic models has the potential to introduce bias in relative risk (RR) estimates. A simulation study was conducted using empirical data to quantify the impact of correlated measurement errors in time-series analyses of air pollution and health. ZIP-code level estimates of exposure for six pollutants (CO, NO x , EC, PM 2.5 , SO 4 , O 3 ) from 1999 to 2002 in the Atlanta metropolitan area were used to calculate spatial, population (i.e. ambient versus personal), and total exposure measurement error. Empirically determined covariance of pollutant concentration pairs and the associated measurement errors were used to simulate true exposure (exposure without error) from observed exposure. Daily emergency department visits for respiratory diseases were simulated using a Poisson time-series model with a main pollutant RR = 1.05 per interquartile range, and a null association for the copollutant (RR = 1). Monte Carlo experiments were used to evaluate the impacts of correlated exposure errors of different copollutant pairs. Substantial attenuation of RRs due to exposure error was evident in nearly all copollutant pairs studied, ranging from 10 to 40% attenuation for spatial error, 3-85% for population error, and 31-85% for total error. When CO, NO x or EC is the main pollutant, we demonstrated the possibility of false positives, specifically identifying significant, positive associations for copollutants based on the estimated type I error rate. The impact of exposure error must be considered when interpreting results of copollutant epidemiologic models, due to the possibility of attenuation of main pollutant RRs and the increased probability of false positives when measurement error is present.

Study of principle error sources in gamma spectrometry. Application to cross sections measurement

International Nuclear Information System (INIS)

Majah, M. Ibn.

1985-01-01

The principle error sources in gamma spectrometry have been studied in purpose to measure cross sections with great precision. Three error sources have been studied: dead time and pile up which depend on counting rate, and coincidence effect that depends on the disintegration scheme of the radionuclide in question. A constant frequency pulse generator has been used to correct the counting loss due to dead time and pile up in cases of long and short disintegration periods. The loss due to coincidence effect can reach 25% and over, depending on the disintegration scheme and on the distance source-detector. After establishing the correction formula and verifying its validity for four examples: iron 56, scandium 48, antimony 120 and gold 196 m, an application has been done by measuring cross sections of nuclear reactions that lead to long disintegration periods which need short distance source-detector counting and thus correcting the loss due to dead time effect, pile up and coincidence effect. 16 refs., 45 figs., 25 tabs. (author)

Errors in abdominal computed tomography

International Nuclear Information System (INIS)

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

1989-01-01

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

Compensation of kinematic geometric parameters error and comparative study of accuracy testing for robot

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Du, Liang; Shi, Guangming; Guan, Weibin; Zhong, Yuansheng; Li, Jin

2014-12-01

Geometric error is the main error of the industrial robot, and it plays a more significantly important fact than other error facts for robot. The compensation model of kinematic error is proposed in this article. Many methods can be used to test the robot accuracy, therefore, how to compare which method is better one. In this article, a method is used to compare two methods for robot accuracy testing. It used Laser Tracker System (LTS) and Three Coordinate Measuring instrument (TCM) to test the robot accuracy according to standard. According to the compensation result, it gets the better method which can improve the robot accuracy apparently.

Dependence of fluence errors in dynamic IMRT on leaf-positional errors varying with time and leaf number

International Nuclear Information System (INIS)

Zygmanski, Piotr; Kung, Jong H.; Jiang, Steve B.; Chin, Lee

2003-01-01

ALPO is an Average Leaf Pair Opening (the concept of ALPO was previously introduced by us in Med. Phys. 28, 2220-2226 (2001). Therefore, dose errors associated with RLP errors are larger for fields requiring small leaf gaps. For an N-field IMRT plan, we demonstrate that the total fluence error (if we neglect inhomogeneities and scatter) is proportional to 1/√(N), where N is the number of fields, which slightly reduces the impact of RLP errors of individual fields on the total fluence error. We tested and applied the analytical apparatus in the context of commercial inverse treatment planning systems used in our clinics (Helios TM and BrainScan TM ). We determined the actual distribution of leaf-positional errors by studying MLC controller (Varian Mark II and Brainlab Novalis MLCs) log files created by the controller after each field delivery. The analytically derived relationship between fluence error and RLP errors was confirmed by numerical simulations. The equivalence of relative fluence error to relative dose error was verified by a direct dose calculation. We also experimentally verified the truthfulness of fluences derived from the log file data by comparing them to film data

Drug dispensing errors in a ward stock system

DEFF Research Database (Denmark)

Andersen, Stig Ejdrup

2010-01-01

. Multivariable analysis showed that surgical and psychiatric settings were more susceptible to involvement in dispensing errors and that polypharmacy was a risk factor. In this ward stock system, dispensing errors are relatively common, they depend on speciality and are associated with polypharmacy......The aim of this study was to determine the frequency of drug dispensing errors in a traditional ward stock system operated by nurses and to investigate the effect of potential contributing factors. This was a descriptive study conducted in a teaching hospital from January 2005 to June 2007. In five....... These results indicate that strategies to reduce dispensing errors should address polypharmacy and focus on high-risk units. This should, however, be substantiated by a future trial....

Students’ Errors in Geometry Viewed from Spatial Intelligence

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Riastuti, N.; Mardiyana, M.; Pramudya, I.

2017-09-01

Geometry is one of the difficult materials because students must have ability to visualize, describe images, draw shapes, and know the kind of shapes. This study aim is to describe student error based on Newmans’ Error Analysis in solving geometry problems viewed from spatial intelligence. This research uses descriptive qualitative method by using purposive sampling technique. The datas in this research are the result of geometri material test and interview by the 8th graders of Junior High School in Indonesia. The results of this study show that in each category of spatial intelligence has a different type of error in solving the problem on the material geometry. Errors are mostly made by students with low spatial intelligence because they have deficiencies in visual abilities. Analysis of student error viewed from spatial intelligence is expected to help students do reflection in solving the problem of geometry.

Correcting for multivariate measurement error by regression calibration in meta-analyses of epidemiological studies.

NARCIS (Netherlands)

Kromhout, D.

2009-01-01

Within-person variability in measured values of multiple risk factors can bias their associations with disease. The multivariate regression calibration (RC) approach can correct for such measurement error and has been applied to studies in which true values or independent repeat measurements of the

On the a priori estimation of collocation error covariance functions: a feasibility study

DEFF Research Database (Denmark)

Arabelos, D.N.; Forsberg, René; Tscherning, C.C.

2007-01-01

and the associated error covariance functions were conducted in the Arctic region north of 64 degrees latitude. The correlation between the known features of the data and the parameters variance and correlation length of the computed error covariance functions was estimated using multiple regression analysis...

Measurement error in epidemiologic studies of air pollution based on land-use regression models.

Science.gov (United States)

Basagaña, Xavier; Aguilera, Inmaculada; Rivera, Marcela; Agis, David; Foraster, Maria; Marrugat, Jaume; Elosua, Roberto; Künzli, Nino

2013-10-15

Land-use regression (LUR) models are increasingly used to estimate air pollution exposure in epidemiologic studies. These models use air pollution measurements taken at a small set of locations and modeling based on geographical covariates for which data are available at all study participant locations. The process of LUR model development commonly includes a variable selection procedure. When LUR model predictions are used as explanatory variables in a model for a health outcome, measurement error can lead to bias of the regression coefficients and to inflation of their variance. In previous studies dealing with spatial predictions of air pollution, bias was shown to be small while most of the effect of measurement error was on the variance. In this study, we show that in realistic cases where LUR models are applied to health data, bias in health-effect estimates can be substantial. This bias depends on the number of air pollution measurement sites, the number of available predictors for model selection, and the amount of explainable variability in the true exposure. These results should be taken into account when interpreting health effects from studies that used LUR models.

Research trend on human error reduction

International Nuclear Information System (INIS)

Miyaoka, Sadaoki

1990-01-01

Human error has been the problem in all industries. In 1988, the Bureau of Mines, Department of the Interior, USA, carried out the worldwide survey on the human error in all industries in relation to the fatal accidents in mines. There was difference in the results according to the methods of collecting data, but the proportion that human error took in the total accidents distributed in the wide range of 20∼85%, and was 35% on the average. The rate of occurrence of accidents and troubles in Japanese nuclear power stations is shown, and the rate of occurrence of human error is 0∼0.5 cases/reactor-year, which did not much vary. Therefore, the proportion that human error took in the total tended to increase, and it has become important to reduce human error for lowering the rate of occurrence of accidents and troubles hereafter. After the TMI accident in 1979 in USA, the research on man-machine interface became active, and after the Chernobyl accident in 1986 in USSR, the problem of organization and management has been studied. In Japan, 'Safety 21' was drawn up by the Advisory Committee for Energy, and also the annual reports on nuclear safety pointed out the importance of human factors. The state of the research on human factors in Japan and abroad and three targets to reduce human error are reported. (K.I.)

Medication errors reported to the National Medication Error Reporting System in Malaysia: a 4-year retrospective review (2009 to 2012).

Science.gov (United States)

Samsiah, A; Othman, Noordin; Jamshed, Shazia; Hassali, Mohamed Azmi; Wan-Mohaina, W M

2016-12-01

Reporting and analysing the data on medication errors (MEs) is important and contributes to a better understanding of the error-prone environment. This study aims to examine the characteristics of errors submitted to the National Medication Error Reporting System (MERS) in Malaysia. A retrospective review of reports received from 1 January 2009 to 31 December 2012 was undertaken. Descriptive statistics method was applied. A total of 17,357 MEs reported were reviewed. The majority of errors were from public-funded hospitals. Near misses were classified in 86.3 % of the errors. The majority of errors (98.1 %) had no harmful effects on the patients. Prescribing contributed to more than three-quarters of the overall errors (76.1 %). Pharmacists detected and reported the majority of errors (92.1 %). Cases of erroneous dosage or strength of medicine (30.75 %) were the leading type of error, whilst cardiovascular (25.4 %) was the most common category of drug found. MERS provides rich information on the characteristics of reported MEs. Low contribution to reporting from healthcare facilities other than government hospitals and non-pharmacists requires further investigation. Thus, a feasible approach to promote MERS among healthcare providers in both public and private sectors needs to be formulated and strengthened. Preventive measures to minimise MEs should be directed to improve prescribing competency among the fallible prescribers identified.

Error Resilient Video Compression Using Behavior Models

Directory of Open Access Journals (Sweden)

Jacco R. Taal

2004-03-01

Full Text Available Wireless and Internet video applications are inherently subjected to bit errors and packet errors, respectively. This is especially so if constraints on the end-to-end compression and transmission latencies are imposed. Therefore, it is necessary to develop methods to optimize the video compression parameters and the rate allocation of these applications that take into account residual channel bit errors. In this paper, we study the behavior of a predictive (interframe video encoder and model the encoders behavior using only the statistics of the original input data and of the underlying channel prone to bit errors. The resulting data-driven behavior models are then used to carry out group-of-pictures partitioning and to control the rate of the video encoder in such a way that the overall quality of the decoded video with compression and channel errors is optimized.

Electronic prescribing reduces prescribing error in public hospitals.

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Shawahna, Ramzi; Rahman, Nisar-Ur; Ahmad, Mahmood; Debray, Marcel; Yliperttula, Marjo; Declèves, Xavier

2011-11-01

To examine the incidence of prescribing errors in a main public hospital in Pakistan and to assess the impact of introducing electronic prescribing system on the reduction of their incidence. Medication errors are persistent in today's healthcare system. The impact of electronic prescribing on reducing errors has not been tested in developing world. Prospective review of medication and discharge medication charts before and after the introduction of an electronic inpatient record and prescribing system. Inpatient records (n = 3300) and 1100 discharge medication sheets were reviewed for prescribing errors before and after the installation of electronic prescribing system in 11 wards. Medications (13,328 and 14,064) were prescribed for inpatients, among which 3008 and 1147 prescribing errors were identified, giving an overall error rate of 22·6% and 8·2% throughout paper-based and electronic prescribing, respectively. Medications (2480 and 2790) were prescribed for discharge patients, among which 418 and 123 errors were detected, giving an overall error rate of 16·9% and 4·4% during paper-based and electronic prescribing, respectively. Electronic prescribing has a significant effect on the reduction of prescribing errors. Prescribing errors are commonplace in Pakistan public hospitals. The study evaluated the impact of introducing electronic inpatient records and electronic prescribing in the reduction of prescribing errors in a public hospital in Pakistan. © 2011 Blackwell Publishing Ltd.

Counting OCR errors in typeset text

Science.gov (United States)

Sandberg, Jonathan S.

1995-03-01

Frequently object recognition accuracy is a key component in the performance analysis of pattern matching systems. In the past three years, the results of numerous excellent and rigorous studies of OCR system typeset-character accuracy (henceforth OCR accuracy) have been published, encouraging performance comparisons between a variety of OCR products and technologies. These published figures are important; OCR vendor advertisements in the popular trade magazines lead readers to believe that published OCR accuracy figures effect market share in the lucrative OCR market. Curiously, a detailed review of many of these OCR error occurrence counting results reveals that they are not reproducible as published and they are not strictly comparable due to larger variances in the counts than would be expected by the sampling variance. Naturally, since OCR accuracy is based on a ratio of the number of OCR errors over the size of the text searched for errors, imprecise OCR error accounting leads to similar imprecision in OCR accuracy. Some published papers use informal, non-automatic, or intuitively correct OCR error accounting. Still other published results present OCR error accounting methods based on string matching algorithms such as dynamic programming using Levenshtein (edit) distance but omit critical implementation details (such as the existence of suspect markers in the OCR generated output or the weights used in the dynamic programming minimization procedure). The problem with not specifically revealing the accounting method is that the number of errors found by different methods are significantly different. This paper identifies the basic accounting methods used to measure OCR errors in typeset text and offers an evaluation and comparison of the various accounting methods.

Radiologic errors, past, present and future.

Science.gov (United States)

Berlin, Leonard

2014-01-01

During the 10-year period beginning in 1949 with publication of five articles in two radiology journals and UKs The Lancet, a California radiologist named L.H. Garland almost single-handedly shocked the entire medical and especially the radiologic community. He focused their attention on the fact now known and accepted by all, but at that time not previously recognized and acknowledged only with great reluctance, that a substantial degree of observer error was prevalent in radiologic interpretation. In the more than half-century that followed, Garland's pioneering work has been affirmed and reaffirmed by numerous researchers. Retrospective studies disclosed then and still disclose today that diagnostic errors in radiologic interpretations of plain radiographic (as well as CT, MR, ultrasound, and radionuclide) images hover in the 30% range, not too dissimilar to the error rates in clinical medicine. Seventy percent of these errors are perceptual in nature, i.e., the radiologist does not "see" the abnormality on the imaging exam, perhaps due to poor conspicuity, satisfaction of search, or simply the "inexplicable psycho-visual phenomena of human perception." The remainder are cognitive errors: the radiologist sees an abnormality but fails to render a correct diagnoses by attaching the wrong significance to what is seen, perhaps due to inadequate knowledge, or an alliterative or judgmental error. Computer-assisted detection (CAD), a technology that for the past two decades has been utilized primarily in mammographic interpretation, increases sensitivity but at the same time decreases specificity; whether it reduces errors is debatable. Efforts to reduce diagnostic radiological errors continue, but the degree to which they will be successful remains to be determined.

Refractive errors in children and adolescents in Bucaramanga (Colombia).

Science.gov (United States)

Galvis, Virgilio; Tello, Alejandro; Otero, Johanna; Serrano, Andrés A; Gómez, Luz María; Castellanos, Yuly

2017-01-01

The aim of this study was to establish the frequency of refractive errors in children and adolescents aged between 8 and 17 years old, living in the metropolitan area of Bucaramanga (Colombia). This study was a secondary analysis of two descriptive cross-sectional studies that applied sociodemographic surveys and assessed visual acuity and refraction. Ametropias were classified as myopic errors, hyperopic errors, and mixed astigmatism. Eyes were considered emmetropic if none of these classifications were made. The data were collated using free software and analyzed with STATA/IC 11.2. One thousand two hundred twenty-eight individuals were included in this study. Girls showed a higher rate of ametropia than boys. Hyperopic refractive errors were present in 23.1% of the subjects, and myopic errors in 11.2%. Only 0.2% of the eyes had high myopia (≤-6.00 D). Mixed astigmatism and anisometropia were uncommon, and myopia frequency increased with age. There were statistically significant steeper keratometric readings in myopic compared to hyperopic eyes. The frequency of refractive errors that we found of 36.7% is moderate compared to the global data. The rates and parameters statistically differed by sex and age groups. Our findings are useful for establishing refractive error rate benchmarks in low-middle-income countries and as a baseline for following their variation by sociodemographic factors.

Refractive errors in children and adolescents in Bucaramanga (Colombia

Directory of Open Access Journals (Sweden)

Virgilio Galvis

Full Text Available ABSTRACT Purpose: The aim of this study was to establish the frequency of refractive errors in children and adolescents aged between 8 and 17 years old, living in the metropolitan area of Bucaramanga (Colombia. Methods: This study was a secondary analysis of two descriptive cross-sectional studies that applied sociodemographic surveys and assessed visual acuity and refraction. Ametropias were classified as myopic errors, hyperopic errors, and mixed astigmatism. Eyes were considered emmetropic if none of these classifications were made. The data were collated using free software and analyzed with STATA/IC 11.2. Results: One thousand two hundred twenty-eight individuals were included in this study. Girls showed a higher rate of ametropia than boys. Hyperopic refractive errors were present in 23.1% of the subjects, and myopic errors in 11.2%. Only 0.2% of the eyes had high myopia (≤-6.00 D. Mixed astigmatism and anisometropia were uncommon, and myopia frequency increased with age. There were statistically significant steeper keratometric readings in myopic compared to hyperopic eyes. Conclusions: The frequency of refractive errors that we found of 36.7% is moderate compared to the global data. The rates and parameters statistically differed by sex and age groups. Our findings are useful for establishing refractive error rate benchmarks in low-middle-income countries and as a baseline for following their variation by sociodemographic factors.

Spelling Errors of Dyslexic Children in Bosnian Language with Transparent Orthography

Science.gov (United States)

Duranovic, Mirela

2017-01-01

The purpose of this study was to explore the nature of spelling errors made by children with dyslexia in Bosnian language with transparent orthography. Three main error categories were distinguished: phonological, orthographic, and grammatical errors. An analysis of error type showed 86% of phonological errors, 10% of orthographic errors, and 4%…

Einstein's error

International Nuclear Information System (INIS)

Winterflood, A.H.

1980-01-01

In discussing Einstein's Special Relativity theory it is claimed that it violates the principle of relativity itself and that an anomalous sign in the mathematics is found in the factor which transforms one inertial observer's measurements into those of another inertial observer. The apparent source of this error is discussed. Having corrected the error a new theory, called Observational Kinematics, is introduced to replace Einstein's Special Relativity. (U.K.)

Study of the Switching Errors in an RSFQ Switch by Using a Computerized Test Setup

International Nuclear Information System (INIS)

Kim, Se Hoon; Baek, Seung Hun; Yang, Jung Kuk; Kim, Jun Ho; Kang, Joon Hee

2005-01-01

The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been a very important issue. In this work, we calculated the bit error rate of an RSFQ switch used in superconductive arithmetic logic unit (ALU). RSFQ switch should have a very low error rate in the optimal bias. Theoretical estimates of the RSFQ error rate are on the order of 10 -50 per bit operation. In this experiment, we prepared two identical circuits placed in parallel. Each circuit was composed of 10 Josephson transmission lines (JTLs) connected in series with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to both circuits. The outputs of the two circuits were compared with an RSFQ exclusive OR (XOR) to measure the bit error rate of the RSFQ switch. By using a computerized bit-error-rate test setup, we measured the bit error rate of 2.18 x 10 -12 when the bias to the RSFQ switch was 0.398 mA that was quite off from the optimum bias of 0.6 mA.

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Comparative study of anatomical normalization errors in SPM and 3D-SSP using digital brain phantom.

Science.gov (United States)

Onishi, Hideo; Matsutake, Yuki; Kawashima, Hiroki; Matsutomo, Norikazu; Amijima, Hizuru

2011-01-01

In single photon emission computed tomography (SPECT) cerebral blood flow studies, two major algorithms are widely used statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP). The aim of this study is to compare an SPM algorithm-based easy Z score imaging system (eZIS) and a 3D-SSP system in the errors of anatomical standardization using 3D-digital brain phantom images. We developed a 3D-brain digital phantom based on MR images to simulate the effects of head tilt, perfusion defective region size, and count value reduction rate on the SPECT images. This digital phantom was used to compare the errors of anatomical standardization by the eZIS and the 3D-SSP algorithms. While the eZIS allowed accurate standardization of the images of the phantom simulating a head in rotation, lateroflexion, anteflexion, or retroflexion without angle dependency, the standardization by 3D-SSP was not accurate enough at approximately 25° or more head tilt. When the simulated head contained perfusion defective regions, one of the 3D-SSP images showed an error of 6.9% from the true value. Meanwhile, one of the eZIS images showed an error as large as 63.4%, revealing a significant underestimation. When required to evaluate regions with decreased perfusion due to such causes as hemodynamic cerebral ischemia, the 3D-SSP is desirable. In a statistical image analysis, we must reconfirm the image after anatomical standardization by all means.

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

Radiation risk estimation based on measurement error models

CERN Document Server

Masiuk, Sergii; Shklyar, Sergiy; Chepurny, Mykola; Likhtarov, Illya

2017-01-01

This monograph discusses statistics and risk estimates applied to radiation damage under the presence of measurement errors. The first part covers nonlinear measurement error models, with a particular emphasis on efficiency of regression parameter estimators. In the second part, risk estimation in models with measurement errors is considered. Efficiency of the methods presented is verified using data from radio-epidemiological studies.

Controlling errors in unidosis carts

Directory of Open Access Journals (Sweden)

Inmaculada Díaz Fernández

2010-01-01

Full Text Available Objective: To identify errors in the unidosis system carts. Method: For two months, the Pharmacy Service controlled medication either returned or missing from the unidosis carts both in the pharmacy and in the wards. Results: Uncorrected unidosis carts show a 0.9% of medication errors (264 versus 0.6% (154 which appeared in unidosis carts previously revised. In carts not revised, the error is 70.83% and mainly caused when setting up unidosis carts. The rest are due to a lack of stock or unavailability (21.6%, errors in the transcription of medical orders (6.81% or that the boxes had not been emptied previously (0.76%. The errors found in the units correspond to errors in the transcription of the treatment (3.46%, non-receipt of the unidosis copy (23.14%, the patient did not take the medication (14.36%or was discharged without medication (12.77%, was not provided by nurses (14.09%, was withdrawn from the stocks of the unit (14.62%, and errors of the pharmacy service (17.56% . Conclusions: It is concluded the need to redress unidosis carts and a computerized prescription system to avoid errors in transcription.Discussion: A high percentage of medication errors is caused by human error. If unidosis carts are overlooked before sent to hospitalization units, the error diminishes to 0.3%.

Reliability and error analysis on xenon/CT CBF

International Nuclear Information System (INIS)

Zhang, Z.

2000-01-01

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

Error-diffusion binarization for joint transform correlators

Science.gov (United States)

Inbar, Hanni; Mendlovic, David; Marom, Emanuel

1993-02-01

A normalized nonlinearly scaled binary joint transform image correlator (JTC) based on a 1D error-diffusion binarization method has been studied. The behavior of the error-diffusion method is compared with hard-clipping, the most widely used method of binarized JTC approaches, using a single spatial light modulator. Computer simulations indicate that the error-diffusion method is advantageous for the production of a binarized power spectrum interference pattern in JTC configurations, leading to better definition of the correlation location. The error-diffusion binary JTC exhibits autocorrelation characteristics which are superior to those of the high-clipping binary JTC over the whole nonlinear scaling range of the Fourier-transform interference intensity for all noise levels considered.

A national physician survey of diagnostic error in paediatrics.

Science.gov (United States)

Perrem, Lucy M; Fanshawe, Thomas R; Sharif, Farhana; Plüddemann, Annette; O'Neill, Michael B

2016-10-01

This cross-sectional survey explored paediatric physician perspectives regarding diagnostic errors. All paediatric consultants and specialist registrars in Ireland were invited to participate in this anonymous online survey. The response rate for the study was 54 % (n = 127). Respondents had a median of 9-year clinical experience (interquartile range (IQR) 4-20 years). A diagnostic error was reported at least monthly by 19 (15.0 %) respondents. Consultants reported significantly less diagnostic errors compared to trainees (p value = 0.01). Cognitive error was the top-ranked contributing factor to diagnostic error, with incomplete history and examination considered to be the principal cognitive error. Seeking a second opinion and close follow-up of patients to ensure that the diagnosis is correct were the highest-ranked, clinician-based solutions to diagnostic error. Inadequate staffing levels and excessive workload were the most highly ranked system-related and situational factors. Increased access to and availability of consultants and experts was the most highly ranked system-based solution to diagnostic error. We found a low level of self-perceived diagnostic error in an experienced group of paediatricians, at variance with the literature and warranting further clarification. The results identify perceptions on the major cognitive, system-related and situational factors contributing to diagnostic error and also key preventative strategies. • Diagnostic errors are an important source of preventable patient harm and have an estimated incidence of 10-15 %. • They are multifactorial in origin and include cognitive, system-related and situational factors. What is New: • We identified a low rate of self-perceived diagnostic error in contrast to the existing literature. • Incomplete history and examination, inadequate staffing levels and excessive workload are cited as the principal contributing factors to diagnostic error in this study.

Errors in chest x-ray interpretation

International Nuclear Information System (INIS)

Woznitza, N.; Piper, K.

2015-01-01

Full text: Reporting of adult chest x-rays by appropriately trained radiographers is frequently used in the United Kingdom as one method to maintain a patient focused radiology service in times of increasing workload. With models of advanced practice being developed in Australia, New Zealand and Canada, the spotlight is on the evidence base which underpins radiographer reporting. It is essential that any radiographer who extends their scope of practice to incorporate definitive clinical reporting perform at a level comparable to a consultant radiologist. In any analysis of performance it is important to quantify levels of sensitivity and specificity and to evaluate areas of error and variation. A critical review of the errors made by reporting radiographers in the interpretation of adult chest x-rays will be performed, examining performance in structured clinical examinations, clinical audit and a diagnostic accuracy study from research undertaken by the authors, and including studies which have compared the performance of reporting radiographers and consultant radiologists. overall performance will be examined and common errors discussed using a case based approach. Methods of error reduction, including multidisciplinary team meetings and ongoing learning will be considered

Errors and violations

International Nuclear Information System (INIS)

Reason, J.

1988-01-01

This paper is in three parts. The first part summarizes the human failures responsible for the Chernobyl disaster and argues that, in considering the human contribution to power plant emergencies, it is necessary to distinguish between: errors and violations; and active and latent failures. The second part presents empirical evidence, drawn from driver behavior, which suggest that errors and violations have different psychological origins. The concluding part outlines a resident pathogen view of accident causation, and seeks to identify the various system pathways along which errors and violations may be propagated

Quasi-eccentricity error modeling and compensation in vision metrology

Science.gov (United States)

Shen, Yijun; Zhang, Xu; Cheng, Wei; Zhu, Limin

2018-04-01

Circular targets are commonly used in vision applications for its detection accuracy and robustness. The eccentricity error of the circular target caused by perspective projection is one of the main factors of measurement error which needs to be compensated in high-accuracy measurement. In this study, the impact of the lens distortion on the eccentricity error is comprehensively investigated. The traditional eccentricity error turns to a quasi-eccentricity error in the non-linear camera model. The quasi-eccentricity error model is established by comparing the quasi-center of the distorted ellipse with the true projection of the object circle center. Then, an eccentricity error compensation framework is proposed which compensates the error by iteratively refining the image point to the true projection of the circle center. Both simulation and real experiment confirm the effectiveness of the proposed method in several vision applications.

A posteriori error estimates in voice source recovery

Science.gov (United States)

Leonov, A. S.; Sorokin, V. N.

2017-12-01

The inverse problem of voice source pulse recovery from a segment of a speech signal is under consideration. A special mathematical model is used for the solution that relates these quantities. A variational method of solving inverse problem of voice source recovery for a new parametric class of sources, that is for piecewise-linear sources (PWL-sources), is proposed. Also, a technique for a posteriori numerical error estimation for obtained solutions is presented. A computer study of the adequacy of adopted speech production model with PWL-sources is performed in solving the inverse problems for various types of voice signals, as well as corresponding study of a posteriori error estimates. Numerical experiments for speech signals show satisfactory properties of proposed a posteriori error estimates, which represent the upper bounds of possible errors in solving the inverse problem. The estimate of the most probable error in determining the source-pulse shapes is about 7-8% for the investigated speech material. It is noted that a posteriori error estimates can be used as a criterion of the quality for obtained voice source pulses in application to speaker recognition.

Heuristics and Cognitive Error in Medical Imaging.

Science.gov (United States)

Itri, Jason N; Patel, Sohil H

2018-05-01

The field of cognitive science has provided important insights into mental processes underlying the interpretation of imaging examinations. Despite these insights, diagnostic error remains a major obstacle in the goal to improve quality in radiology. In this article, we describe several types of cognitive bias that lead to diagnostic errors in imaging and discuss approaches to mitigate cognitive biases and diagnostic error. Radiologists rely on heuristic principles to reduce complex tasks of assessing probabilities and predicting values into simpler judgmental operations. These mental shortcuts allow rapid problem solving based on assumptions and past experiences. Heuristics used in the interpretation of imaging studies are generally helpful but can sometimes result in cognitive biases that lead to significant errors. An understanding of the causes of cognitive biases can lead to the development of educational content and systematic improvements that mitigate errors and improve the quality of care provided by radiologists.

Imagery of Errors in Typing

Science.gov (United States)

Rieger, Martina; Martinez, Fanny; Wenke, Dorit

2011-01-01

Using a typing task we investigated whether insufficient imagination of errors and error corrections is related to duration differences between execution and imagination. In Experiment 1 spontaneous error imagination was investigated, whereas in Experiment 2 participants were specifically instructed to imagine errors. Further, in Experiment 2 we…

A phantom-based study for assessing the error and uncertainty of a neuronavigation system

OpenAIRE

Natalia Izquierdo-Cifuentes; Genaro Daza-Santacoloma; Walter Serna-Serna

2017-01-01

This document describes a calibration protocol with the intention to introduce a guide to standardize the metrological vocabulary among manufacturers of image-guided surgery systems. Two stages were developed to measure the errors and estimate the uncertainty of a neuronavigator in different situations, on the first one it was determined a mechanical error on a virtual model of an acrylic phantom, on the second it was determined a coordinate error on the computerized axial tomography scan of ...

Enhancing Intervention for Residual Rhotic Errors Via App-Delivered Biofeedback: A Case Study.

Science.gov (United States)

Byun, Tara McAllister; Campbell, Heather; Carey, Helen; Liang, Wendy; Park, Tae Hong; Svirsky, Mario

2017-06-22

Recent research suggests that visual-acoustic biofeedback can be an effective treatment for residual speech errors, but adoption remains limited due to barriers including high cost and lack of familiarity with the technology. This case study reports results from the first participant to complete a course of visual-acoustic biofeedback using a not-for-profit iOS app, Speech Therapist's App for /r/ Treatment. App-based biofeedback treatment for rhotic misarticulation was provided in weekly 30-min sessions for 20 weeks. Within-treatment progress was documented using clinician perceptual ratings and acoustic measures. Generalization gains were assessed using acoustic measures of word probes elicited during baseline, treatment, and maintenance sessions. Both clinician ratings and acoustic measures indicated that the participant significantly improved her rhotic production accuracy in trials elicited during treatment sessions. However, these gains did not transfer to generalization probes. This study provides a proof-of-concept demonstration that app-based biofeedback is a viable alternative to costlier dedicated systems. Generalization of gains to contexts without biofeedback remains a challenge that requires further study. App-delivered biofeedback could enable clinician-research partnerships that would strengthen the evidence base while providing enhanced treatment for children with residual rhotic errors. https://doi.org/10.23641/asha.5116318.

Common Positioning Errors in Digital Panoramic Radiographies Taken In Mashhad Dental School

Directory of Open Access Journals (Sweden)

Ali Bagherpour

2018-06-01

Full Text Available Introduction: The present study was aimed at evaluating common positioning errors on panoramic radiographs taken in the Radiology Department of Mashhad Dental School. Materials and methods: The study sample included 1,990 digital panoramic radiographs taken in the Radiology Department of Mashhad Dental School by a Planmeca Promax (Planmeca Oy, Helsinki, Finland, during a 2-year period (2010–2012. All radiographs, according to dentition and sex, were evaluated for positioning errors. Results: There were 1,927 (96.8% panoramic radiographs with one or more errors. While the number of errors in each image varied between one and five, most images had one error (48.4%. The most common error was that the tongue was not in contact with the hard palate (94.8%. "Open lips" was an error not seen in any patients. Conclusions:positioning errors are common in panoramic radiographies. The most common error observed in this study was a failure to place the tongue on the palate. This error and the other errors reported in this study can be reduced by training the technicians and spending little more time for patient positioning and more effective communication with the patients.

The computation of equating errors in international surveys in education.

Science.gov (United States)

Monseur, Christian; Berezner, Alla

2007-01-01

Since the IEA's Third International Mathematics and Science Study, one of the major objectives of international surveys in education has been to report trends in achievement. The names of the two current IEA surveys reflect this growing interest: Trends in International Mathematics and Science Study (TIMSS) and Progress in International Reading Literacy Study (PIRLS). Similarly a central concern of the OECD's PISA is with trends in outcomes over time. To facilitate trend analyses these studies link their tests using common item equating in conjunction with item response modelling methods. IEA and PISA policies differ in terms of reporting the error associated with trends. In IEA surveys, the standard errors of the trend estimates do not include the uncertainty associated with the linking step while PISA does include a linking error component in the standard errors of trend estimates. In other words, PISA implicitly acknowledges that trend estimates partly depend on the selected common items, while the IEA's surveys do not recognise this source of error. Failing to recognise the linking error leads to an underestimation of the standard errors and thus increases the Type I error rate, thereby resulting in reporting of significant changes in achievement when in fact these are not significant. The growing interest of policy makers in trend indicators and the impact of the evaluation of educational reforms appear to be incompatible with such underestimation. However, the procedure implemented by PISA raises a few issues about the underlying assumptions for the computation of the equating error. After a brief introduction, this paper will describe the procedure PISA implemented to compute the linking error. The underlying assumptions of this procedure will then be discussed. Finally an alternative method based on replication techniques will be presented, based on a simulation study and then applied to the PISA 2000 data.

Grammar Errors in the Writing of Iraqi English Language Learners

Directory of Open Access Journals (Sweden)

Yasir Bdaiwi Jasim Al-Shujairi

2017-10-01

Full Text Available Several studies have been conducted to investigate the grammatical errors of Iraqi postgraduates and undergraduates in their academic writing. However, few studies have focused on the writing challenges that Iraqi pre-university students face. This research aims at examining the written discourse of Iraqi high school students and the common grammatical errors they make in their writing. The study had a mixed methods design. Through convenience sampling method, 112 compositions were collected from Iraqi pre-university students. For purpose of triangulation, an interview was conducted. The data was analyzed using Corder’s (1967 error analysis model and James’ (1998 framework of grammatical errors. Furthermore, Brown’s (2000 taxonomy was adopted to classify the types of errors. The result showed that Iraqi high school students have serious problems with the usage of verb tenses, articles, and prepositions. Moreover, the most frequent types of errors were Omission and Addition. Furthermore, it was found that intralanguage was the dominant source of errors. These findings may enlighten Iraqi students on the importance of correct grammar use for writing efficacy.

Sensation seeking and error processing.

Science.gov (United States)

Zheng, Ya; Sheng, Wenbin; Xu, Jing; Zhang, Yuanyuan

2014-09-01

Sensation seeking is defined by a strong need for varied, novel, complex, and intense stimulation, and a willingness to take risks for such experience. Several theories propose that the insensitivity to negative consequences incurred by risks is one of the hallmarks of sensation-seeking behaviors. In this study, we investigated the time course of error processing in sensation seeking by recording event-related potentials (ERPs) while high and low sensation seekers performed an Eriksen flanker task. Whereas there were no group differences in ERPs to correct trials, sensation seeking was associated with a blunted error-related negativity (ERN), which was female-specific. Further, different subdimensions of sensation seeking were related to ERN amplitude differently. These findings indicate that the relationship between sensation seeking and error processing is sex-specific. Copyright © 2014 Society for Psychophysiological Research.

Prioritising interventions against medication errors

DEFF Research Database (Denmark)

Lisby, Marianne; Pape-Larsen, Louise; Sørensen, Ann Lykkegaard

errors are therefore needed. Development of definition: A definition of medication errors including an index of error types for each stage in the medication process was developed from existing terminology and through a modified Delphi-process in 2008. The Delphi panel consisted of 25 interdisciplinary......Abstract Authors: Lisby M, Larsen LP, Soerensen AL, Nielsen LP, Mainz J Title: Prioritising interventions against medication errors – the importance of a definition Objective: To develop and test a restricted definition of medication errors across health care settings in Denmark Methods: Medication...... errors constitute a major quality and safety problem in modern healthcare. However, far from all are clinically important. The prevalence of medication errors ranges from 2-75% indicating a global problem in defining and measuring these [1]. New cut-of levels focusing the clinical impact of medication...

A Study on Large Display Panel Design for the Countermeasures against Team Errors within the Main Control Room of APR-1400

Energy Technology Data Exchange (ETDEWEB)

Kim, Sa Kil; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The personal aspect of human errors has been mainly overcome by virtue of the education and training. However, in the system aspect, the education and training system needs to be reconsidered for more effective reduction of human errors affected from various systems hazards. Traditionally the education and training systems are mainly not focused on team skills such as communication, situational awareness, and coordination, etc. but individual knowledge, skill, and attitude. However, the team factor is one of the crucial issues to reduce the human errors in most industries. In this study, we identify the emerging types of team errors, especially, in digitalized control room of nuclear power plants such as the APR-1400 main control room. Most works in nuclear industry are to be performed by a team of more than two persons. Even though the individual errors can be detected and recovered by the qualified others and/or the well trained team, it is rather seldom that the errors by team could be easily detected and properly recovered by the team itself. Note that the team is defined as two or more people who are appropriately interacting with each other, and the team is a dependent aggregate, which accomplishes a valuable goal. Team error is one of the typical organizational errors that may occur during performing operations in nuclear power plants. The large display panel is a representative feature of digitalized control room. As a group-view display, the large display panel provides plant overview to the operators. However, in terms of team performance and team errors, the large display panel is on a discussion board still because the large display panel was designed just a concept of passive display. In this study, we will propose revised large display panel which is integrated with several alternative interfaces against feasible team errors.

A Study on Large Display Panel Design for the Countermeasures against Team Errors within the Main Control Room of APR-1400

International Nuclear Information System (INIS)

Kim, Sa Kil; Lee, Yong Hee

2015-01-01

The personal aspect of human errors has been mainly overcome by virtue of the education and training. However, in the system aspect, the education and training system needs to be reconsidered for more effective reduction of human errors affected from various systems hazards. Traditionally the education and training systems are mainly not focused on team skills such as communication, situational awareness, and coordination, etc. but individual knowledge, skill, and attitude. However, the team factor is one of the crucial issues to reduce the human errors in most industries. In this study, we identify the emerging types of team errors, especially, in digitalized control room of nuclear power plants such as the APR-1400 main control room. Most works in nuclear industry are to be performed by a team of more than two persons. Even though the individual errors can be detected and recovered by the qualified others and/or the well trained team, it is rather seldom that the errors by team could be easily detected and properly recovered by the team itself. Note that the team is defined as two or more people who are appropriately interacting with each other, and the team is a dependent aggregate, which accomplishes a valuable goal. Team error is one of the typical organizational errors that may occur during performing operations in nuclear power plants. The large display panel is a representative feature of digitalized control room. As a group-view display, the large display panel provides plant overview to the operators. However, in terms of team performance and team errors, the large display panel is on a discussion board still because the large display panel was designed just a concept of passive display. In this study, we will propose revised large display panel which is integrated with several alternative interfaces against feasible team errors

A comparative study of voluntarily reported medication errors among ...

African Journals Online (AJOL)

errors among adult patients in intensive care (IC) and non-. IC settings in Riyadh, ... safety “To err is human: Building a safer health care system” .... regression analysis was used to identify factors affecting the .... that work in non-ICU areas are less likely to report such ... ve.org/read), which permit unrestricted use, distribution ...

Crystalline lens power and refractive error.

Science.gov (United States)

Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

2012-02-01

To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

Science.gov (United States)

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-04-01

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al2O3:C dosimetry and a novel statistical error decision criterion

International Nuclear Information System (INIS)

Kertzscher, Gustavo; Andersen, Claus E.; Siebert, Frank-Andre; Nielsen, Soren Kynde; Lindegaard, Jacob C.; Tanderup, Kari

2011-01-01

Background and purpose: The feasibility of a real-time in vivo dosimeter to detect errors has previously been demonstrated. The purpose of this study was to: (1) quantify the sensitivity of the dosimeter to detect imposed treatment errors under well controlled and clinically relevant experimental conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Materials and methods: Phantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed treatment errors, including interchanged pairs of afterloader guide tubes and 2-20 mm source displacements, were monitored using a real-time fiber-coupled carbon doped aluminum oxide (Al 2 O 3 :C) crystal dosimeter that was positioned in the reconstructed tumor region. The error detection capacity was evaluated at three dose levels: dwell position, source channel, and fraction. The error criterion incorporated the correlated source position uncertainties and other sources of uncertainty, and it was applied both for the specific phantom patient plans and for a general case (source-detector distance 5-90 mm and position uncertainty 1-4 mm). Results: Out of 20 interchanged guide tube errors, time-resolved analysis identified 17 while fraction level analysis identified two. Channel and fraction level comparisons could leave 10 mm dosimeter displacement errors unidentified. Dwell position dose rate comparisons correctly identified displacements ≥5 mm. Conclusion: This phantom study demonstrates that Al 2 O 3 :C real-time dosimetry can identify applicator displacements ≥5 mm and interchanged guide tube errors during PDR and HDR brachytherapy. The study demonstrates the shortcoming of a constant error criterion and the advantage of a statistical error criterion.

Metering error quantification under voltage and current waveform distortion

Science.gov (United States)

Wang, Tao; Wang, Jia; Xie, Zhi; Zhang, Ran

2017-09-01

With integration of more and more renewable energies and distortion loads into power grid, the voltage and current waveform distortion results in metering error in the smart meters. Because of the negative effects on the metering accuracy and fairness, it is an important subject to study energy metering combined error. In this paper, after the comparing between metering theoretical value and real recorded value under different meter modes for linear and nonlinear loads, a quantification method of metering mode error is proposed under waveform distortion. Based on the metering and time-division multiplier principles, a quantification method of metering accuracy error is proposed also. Analyzing the mode error and accuracy error, a comprehensive error analysis method is presented which is suitable for new energy and nonlinear loads. The proposed method has been proved by simulation.

Financial impact of errors in business forecasting: a comparative study of linear models and neural networks

Directory of Open Access Journals (Sweden)

Claudimar Pereira da Veiga

2012-08-01

Full Text Available The importance of demand forecasting as a management tool is a well documented issue. However, it is difficult to measure costs generated by forecasting errors and to find a model that assimilate the detailed operation of each company adequately. In general, when linear models fail in the forecasting process, more complex nonlinear models are considered. Although some studies comparing traditional models and neural networks have been conducted in the literature, the conclusions are usually contradictory. In this sense, the objective was to compare the accuracy of linear methods and neural networks with the current method used by the company. The results of this analysis also served as input to evaluate influence of errors in demand forecasting on the financial performance of the company. The study was based on historical data from five groups of food products, from 2004 to 2008. In general, one can affirm that all models tested presented good results (much better than the current forecasting method used, with mean absolute percent error (MAPE around 10%. The total financial impact for the company was 6,05% on annual sales.

An Investigation of effective factors on nurses\\' speech errors

Directory of Open Access Journals (Sweden)

Maryam Tafaroji yeganeh

2017-03-01

Full Text Available Background : Speech errors are a branch of psycholinguistic science. Speech error or slip of tongue is a natural process that happens to everyone. The importance of this research is because of sensitivity and importance of nursing in which the speech errors may be interfere in the treatment of patients, but unfortunately no research has been done yet in this field.This research has been done to study the factors (personality, stress, fatigue and insomnia which cause speech errors happen to nurses of Ilam province. Materials and Methods: The sample of this correlation-descriptive research consists of 50 nurses working in Mustafa Khomeini Hospital of Ilam province who were selected randomly. Our data were collected using The Minnesota Multiphasic Personality Inventory, NEO-Five Factor Inventory and Expanded Nursing Stress Scale, and were analyzed using SPSS version 20, descriptive, inferential and multivariate linear regression or two-variable statistical methods (with significant level: p≤0. 05. Results: 30 (60% of nurses participating in the study were female and 19 (38% were male. In this study, all three factors (type of personality, stress and fatigue have significant effects on nurses' speech errors Conclusion: 30 (60% of nurses participating in the study were female and 19 (38% were male. In this study, all three factors (type of personality, stress and fatigue have significant effects on nurses' speech errors.

Error-information in tutorial documentation: Supporting users' errors to facilitate initial skill learning

NARCIS (Netherlands)

Lazonder, Adrianus W.; van der Meij, Hans

1995-01-01

Novice users make many errors when they first try to learn how to work with a computer program like a spreadsheet or wordprocessor. No matter how user-friendly the software or the training manual, errors can and will occur. The current view on errors is that they can be helpful or disruptive,

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)

Medical Errors in Cyprus: The 2005 Eurobarometer Survey

Directory of Open Access Journals (Sweden)

Andreas Pavlakis

2012-01-01

Full Text Available Background: Medical errors have been highlighted in recent years by different agencies, scientific bodies and research teams alike. We sought to explore the issue of medical errors in Cyprus using data from the Eurobarometer survey.Methods: Data from the special Eurobarometer survey conducted in 2005 across all European Union countries (EU-25 and the acceding countries were obtained from the corresponding EU office. Statisticalanalyses including logistic regression models were performed using SPSS.Results: A total of 502 individuals participated in the Cyprus survey. About 90% reported that they had often or sometimes heard about medical errors, while 22% reported that a family member or they had suffered a serious medical error in a local hospital. In addition, 9.4% reported a serious problem from a prescribed medicine. We also found statistically significant differences across different ages and gender and in rural versus urban residents. Finally, using multivariable-adjusted logistic regression models, wefound that residents in rural areas were more likely to have suffered a serious medical error in a local hospital or from a prescribed medicine.Conclusion: Our study shows that the vast majority of residents in Cyprus in parallel with the other Europeans worry about medical errors and a significant percentage report having suffered a serious medical error at a local hospital or from a prescribed medicine. The results of our study could help the medical community in Cyprus and the society at large to enhance its vigilance with respect to medical errors in order to improve medical care.

Recognition of medical errors' reporting system dimensions in educational hospitals.

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Yarmohammadian, Mohammad H; Mohammadinia, Leila; Tavakoli, Nahid; Ghalriz, Parvin; Haghshenas, Abbas

2014-01-01

Nowadays medical errors are one of the serious issues in the health-care system and carry to account of the patient's safety threat. The most important step for achieving safety promotion is identifying errors and their causes in order to recognize, correct and omit them. Concerning about repeating medical errors and harms, which were received via theses errors concluded to designing and establishing medical error reporting systems for hospitals and centers that are presenting therapeutic services. The aim of this study is the recognition of medical errors' reporting system dimensions in educational hospitals. This research is a descriptive-analytical and qualities' study, which has been carried out in Shahid Beheshti educational therapeutic center in Isfahan during 2012. In this study, relevant information was collected through 15 face to face interviews. That each of interviews take place in about 1hr and creation of five focused discussion groups through 45 min for each section, they were composed of Metron, educational supervisor, health officer, health education, and all of the head nurses. Concluded data interviews and discussion sessions were coded, then achieved results were extracted in the presence of clear-sighted persons and after their feedback perception, they were categorized. In order to make sure of information correctness, tables were presented to the research's interviewers and final the corrections were confirmed based on their view. The extracted information from interviews and discussion groups have been divided into nine main categories after content analyzing and subject coding and their subsets have been completely expressed. Achieved dimensions are composed of nine domains of medical error concept, error cases according to nurses' prospection, medical error reporting barriers, employees' motivational factors for error reporting, purposes of medical error reporting system, error reporting's challenges and opportunities, a desired system

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

Learning mechanisms to limit medication administration errors.

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Drach-Zahavy, Anat; Pud, Dorit

2010-04-01

This paper is a report of a study conducted to identify and test the effectiveness of learning mechanisms applied by the nursing staff of hospital wards as a means of limiting medication administration errors. Since the influential report ;To Err Is Human', research has emphasized the role of team learning in reducing medication administration errors. Nevertheless, little is known about the mechanisms underlying team learning. Thirty-two hospital wards were randomly recruited. Data were collected during 2006 in Israel by a multi-method (observations, interviews and administrative data), multi-source (head nurses, bedside nurses) approach. Medication administration error was defined as any deviation from procedures, policies and/or best practices for medication administration, and was identified using semi-structured observations of nurses administering medication. Organizational learning was measured using semi-structured interviews with head nurses, and the previous year's reported medication administration errors were assessed using administrative data. The interview data revealed four learning mechanism patterns employed in an attempt to learn from medication administration errors: integrated, non-integrated, supervisory and patchy learning. Regression analysis results demonstrated that whereas the integrated pattern of learning mechanisms was associated with decreased errors, the non-integrated pattern was associated with increased errors. Supervisory and patchy learning mechanisms were not associated with errors. Superior learning mechanisms are those that represent the whole cycle of team learning, are enacted by nurses who administer medications to patients, and emphasize a system approach to data analysis instead of analysis of individual cases.

Examining the link between burnout and medical error: A checklist approach

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Evangelia Tsiga

2017-09-01

Conclusions: The Medical Error Checklists developed in this study advance the study of medical errors by proposing a comprehensive, valid and reliable self-assessment tool. The results highlight the importance of hospital organizational factors in preventing medical errors.

Prescribing Errors in Cardiovascular Diseases in a Tertiary Health ...

African Journals Online (AJOL)

Prescription errors are now known to be contributing to a large number of deaths during the treatment of cardiovascular diseases. However, there is paucity of information about these errors occurring in health facilities in Nigeria. The objective of this study was to investigate the prevalence of prescribing errors in ...

Medication errors in outpatient care in Colombia, 2005-2013.

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Machado-Alba, Jorge E; Moncada, Juan Carlos; Moreno-Gutiérrez, Paula Andrea

2016-06-03

Medication errors outside the hospital have been poorly studied despite representing an important threat to patient safety. To describe the characteristics of medication errors in outpatient dispensing pharmacists reported in a pharmaco-surveillance system between 2005 and 2013 in Colombia. We conducted a descriptive study by reviewing and categorizing medication error reports from outpatient pharmacy services to a national medication dispensing company between January, 2005 and September, 2013. Variables considered included: process involved (administration, dispensing, prescription and transcription), wrong drug, time delay for the report, error type, cause and severity. The analysis was conducted in the SPSS® software, version 22.0. A total of 14,873 medication errors were reviewed, of which 67.2% in fact occurred, 15.5% reached the patient and 0.7% caused harm. Administration (OR=93.61, CI 95%: 48.510-180.655, perrors (OR=5.64; CI 95%: 3.488-9.142, perror reaching the patient. It is necessary to develop surveillance systems for medication errors in ambulatory care, focusing on the prescription, transcription and dispensation processes. Special strategies are needed for the prevention of medication errors related to anti-infective drugs.

Meniscal tear. Diagnostic errors in MR imaging

International Nuclear Information System (INIS)

Barrera, M. C.; Recondo, J. A.; Gervas, C.; Fernandez, E.; Villanua, J. A.M.; Salvador, E.

2003-01-01

To analyze diagnostic discrepancies found between magnetic resonance (MR) and arthroscopy, and the determine the reasons that they occur. Two-hundred and forty-eight MR knee explorations were retrospectively checked. Forty of these showed diagnostic discrepancies between MR and arthroscopy. Two radiologists independently re-analyzed the images from 29 of the 40 studies without knowing which diagnosis had resulted from which of the two techniques. Their interpretations were correlated with the initial MR diagnosis, MR images and arthroscopic results. Initial errors in MR imaging were classified as either unavoidable, interpretive, or secondary to equivocal findings. Eleven MR examinations could not be checked since their corresponding imaging results could not be located. Of 34 errors found in the original diagnoses, 12 (35.5%)were classified as unavoidable, 14 (41.2%) as interpretative and 8 (23.5%) as secondary to equivocal findings. 41.2% of the errors were avoided in the retrospective study probably due to our department having greater experience in interpreting MR images, 25.5% were unavailable even in the retrospective study. A small percentage of diagnostic errors were due to the presence of subtle equivocal findings. (Author) 15 refs

Systematic analysis of video data from different human–robot interaction studies: a categorization of social signals during error situations

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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

Systematic analysis of video data from different human-robot interaction studies: a categorization of social signals during error situations.

Science.gov (United States)

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.

Comparative study of anatomical normalization errors in SPM and 3D-SSP using digital brain phantom

International Nuclear Information System (INIS)

Onishi, Hideo; Matsutomo, Norikazu; Matsutake, Yuki; Kawashima, Hiroki; Amijima, Hizuru

2011-01-01

In single photon emission computed tomography (SPECT) cerebral blood flow studies, two major algorithms are widely used statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP). The aim of this study is to compare an SPM algorithm-based easy Z score imaging system (eZIS) and a 3D-SSP system in the errors of anatomical standardization using 3D-digital brain phantom images. We developed a 3D-brain digital phantom based on MR images to simulate the effects of head tilt, perfusion defective region size, and count value reduction rate on the SPECT images. This digital phantom was used to compare the errors of anatomical standardization by the eZIS and the 3D-SSP algorithms. While the eZIS allowed accurate standardization of the images of the phantom simulating a head in rotation, lateroflexion, anteflexion, or retroflexion without angle dependency, the standardization by 3D-SSP was not accurate enough at approximately 25 deg or more head tilt. When the simulated head contained perfusion defective regions, one of the 3D-SSP images showed an error of 6.9% from the true value. Meanwhile, one of the eZIS images showed an error as large as 63.4%, revealing a significant underestimation. When required to evaluate regions with decreased perfusion due to such causes as hemodynamic cerebral ischemia, the 3D-SSP is desirable. In a statistical image analysis, we must reconfirm the image after anatomical standardization by all means. (author)

Incorporating Measurement Error from Modeled Air Pollution Exposures into Epidemiological Analyses.

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Samoli, Evangelia; Butland, Barbara K

2017-12-01

Outdoor air pollution exposures used in epidemiological studies are commonly predicted from spatiotemporal models incorporating limited measurements, temporal factors, geographic information system variables, and/or satellite data. Measurement error in these exposure estimates leads to imprecise estimation of health effects and their standard errors. We reviewed methods for measurement error correction that have been applied in epidemiological studies that use model-derived air pollution data. We identified seven cohort studies and one panel study that have employed measurement error correction methods. These methods included regression calibration, risk set regression calibration, regression calibration with instrumental variables, the simulation extrapolation approach (SIMEX), and methods under the non-parametric or parameter bootstrap. Corrections resulted in small increases in the absolute magnitude of the health effect estimate and its standard error under most scenarios. Limited application of measurement error correction methods in air pollution studies may be attributed to the absence of exposure validation data and the methodological complexity of the proposed methods. Future epidemiological studies should consider in their design phase the requirements for the measurement error correction method to be later applied, while methodological advances are needed under the multi-pollutants setting.

Evaluation of drug administration errors in a teaching hospital

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Berdot Sarah

2012-03-01

Full Text Available Abstract Background Medication errors can occur at any of the three steps of the medication use process: prescribing, dispensing and administration. We aimed to determine the incidence, type and clinical importance of drug administration errors and to identify risk factors. Methods Prospective study based on disguised observation technique in four wards in a teaching hospital in Paris, France (800 beds. A pharmacist accompanied nurses and witnessed the preparation and administration of drugs to all patients during the three drug rounds on each of six days per ward. Main outcomes were number, type and clinical importance of errors and associated risk factors. Drug administration error rate was calculated with and without wrong time errors. Relationship between the occurrence of errors and potential risk factors were investigated using logistic regression models with random effects. Results Twenty-eight nurses caring for 108 patients were observed. Among 1501 opportunities for error, 415 administrations (430 errors with one or more errors were detected (27.6%. There were 312 wrong time errors, ten simultaneously with another type of error, resulting in an error rate without wrong time error of 7.5% (113/1501. The most frequently administered drugs were the cardiovascular drugs (425/1501, 28.3%. The highest risks of error in a drug administration were for dermatological drugs. No potentially life-threatening errors were witnessed and 6% of errors were classified as having a serious or significant impact on patients (mainly omission. In multivariate analysis, the occurrence of errors was associated with drug administration route, drug classification (ATC and the number of patient under the nurse's care. Conclusion Medication administration errors are frequent. The identification of its determinants helps to undertake designed interventions.

Dependence of the compensation error on the error of a sensor and corrector in an adaptive optics phase-conjugating system

International Nuclear Information System (INIS)

Kiyko, V V; Kislov, V I; Ofitserov, E N

2015-01-01

In the framework of a statistical model of an adaptive optics system (AOS) of phase conjugation, three algorithms based on an integrated mathematical approach are considered, each of them intended for minimisation of one of the following characteristics: the sensor error (in the case of an ideal corrector), the corrector error (in the case of ideal measurements) and the compensation error (with regard to discreteness and measurement noises and to incompleteness of a system of response functions of the corrector actuators). Functional and statistical relationships between the algorithms are studied and a relation is derived to ensure calculation of the mean-square compensation error as a function of the errors of the sensor and corrector with an accuracy better than 10%. Because in adjusting the AOS parameters, it is reasonable to proceed from the equality of the sensor and corrector errors, in the case the Hartmann sensor is used as a wavefront sensor, the required number of actuators in the absence of the noise component in the sensor error turns out 1.5 – 2.5 times less than the number of counts, and that difference grows with increasing measurement noise. (adaptive optics)

Dependence of the compensation error on the error of a sensor and corrector in an adaptive optics phase-conjugating system

Energy Technology Data Exchange (ETDEWEB)

Kiyko, V V; Kislov, V I; Ofitserov, E N [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2015-08-31

In the framework of a statistical model of an adaptive optics system (AOS) of phase conjugation, three algorithms based on an integrated mathematical approach are considered, each of them intended for minimisation of one of the following characteristics: the sensor error (in the case of an ideal corrector), the corrector error (in the case of ideal measurements) and the compensation error (with regard to discreteness and measurement noises and to incompleteness of a system of response functions of the corrector actuators). Functional and statistical relationships between the algorithms are studied and a relation is derived to ensure calculation of the mean-square compensation error as a function of the errors of the sensor and corrector with an accuracy better than 10%. Because in adjusting the AOS parameters, it is reasonable to proceed from the equality of the sensor and corrector errors, in the case the Hartmann sensor is used as a wavefront sensor, the required number of actuators in the absence of the noise component in the sensor error turns out 1.5 – 2.5 times less than the number of counts, and that difference grows with increasing measurement noise. (adaptive optics)

Evaluating Method Engineer Performance: an error classification and preliminary empirical study

Directory of Open Access Journals (Sweden)

Steven Kelly

1998-11-01

Full Text Available We describe an approach to empirically test the use of metaCASE environments to model methods. Both diagrams and matrices have been proposed as a means for presenting the methods. These different paradigms may have their own effects on how easily and well users can model methods. We extend Batra's classification of errors in data modelling to cover metamodelling, and use it to measure the performance of a group of metamodellers using either diagrams or matrices. The tentative results from this pilot study confirm the usefulness of the classification, and show some interesting differences between the paradigms.

Social aspects of clinical errors.

Science.gov (United States)

Richman, Joel; Mason, Tom; Mason-Whitehead, Elizabeth; McIntosh, Annette; Mercer, Dave

2009-08-01

Clinical errors, whether committed by doctors, nurses or other professions allied to healthcare, remain a sensitive issue requiring open debate and policy formulation in order to reduce them. The literature suggests that the issues underpinning errors made by healthcare professionals involve concerns about patient safety, professional disclosure, apology, litigation, compensation, processes of recording and policy development to enhance quality service. Anecdotally, we are aware of narratives of minor errors, which may well have been covered up and remain officially undisclosed whilst the major errors resulting in damage and death to patients alarm both professionals and public with resultant litigation and compensation. This paper attempts to unravel some of these issues by highlighting the historical nature of clinical errors and drawing parallels to contemporary times by outlining the 'compensation culture'. We then provide an overview of what constitutes a clinical error and review the healthcare professional strategies for managing such errors.

Speech Errors in Progressive Non-Fluent Aphasia

Science.gov (United States)

Ash, Sharon; McMillan, Corey; Gunawardena, Delani; Avants, Brian; Morgan, Brianna; Khan, Alea; Moore, Peachie; Gee, James; Grossman, Murray

2010-01-01

The nature and frequency of speech production errors in neurodegenerative disease have not previously been precisely quantified. In the present study, 16 patients with a progressive form of non-fluent aphasia (PNFA) were asked to tell a story from a wordless children's picture book. Errors in production were classified as either phonemic,…

Medication errors in the Middle East countries: a systematic review of the literature.

Science.gov (United States)

Alsulami, Zayed; Conroy, Sharon; Choonara, Imti

2013-04-01

Medication errors are a significant global concern and can cause serious medical consequences for patients. Little is known about medication errors in Middle Eastern countries. The objectives of this systematic review were to review studies of the incidence and types of medication errors in Middle Eastern countries and to identify the main contributory factors involved. A systematic review of the literature related to medication errors in Middle Eastern countries was conducted in October 2011 using the following databases: Embase, Medline, Pubmed, the British Nursing Index and the Cumulative Index to Nursing & Allied Health Literature. The search strategy included all ages and languages. Inclusion criteria were that the studies assessed or discussed the incidence of medication errors and contributory factors to medication errors during the medication treatment process in adults or in children. Forty-five studies from 10 of the 15 Middle Eastern countries met the inclusion criteria. Nine (20 %) studies focused on medication errors in paediatric patients. Twenty-one focused on prescribing errors, 11 measured administration errors, 12 were interventional studies and one assessed transcribing errors. Dispensing and documentation errors were inadequately evaluated. Error rates varied from 7.1 % to 90.5 % for prescribing and from 9.4 % to 80 % for administration. The most common types of prescribing errors reported were incorrect dose (with an incidence rate from 0.15 % to 34.8 % of prescriptions), wrong frequency and wrong strength. Computerised physician rder entry and clinical pharmacist input were the main interventions evaluated. Poor knowledge of medicines was identified as a contributory factor for errors by both doctors (prescribers) and nurses (when administering drugs). Most studies did not assess the clinical severity of the medication errors. Studies related to medication errors in the Middle Eastern countries were relatively few in number and of poor quality

Assessing type I error and power of multistate Markov models for panel data-A simulation study.

Science.gov (United States)

Cassarly, Christy; Martin, Renee' H; Chimowitz, Marc; Peña, Edsel A; Ramakrishnan, Viswanathan; Palesch, Yuko Y

2017-01-01

Ordinal outcomes collected at multiple follow-up visits are common in clinical trials. Sometimes, one visit is chosen for the primary analysis and the scale is dichotomized amounting to loss of information. Multistate Markov models describe how a process moves between states over time. Here, simulation studies are performed to investigate the type I error and power characteristics of multistate Markov models for panel data with limited non-adjacent state transitions. The results suggest that the multistate Markov models preserve the type I error and adequate power is achieved with modest sample sizes for panel data with limited non-adjacent state transitions.

Abstract probabilistic CNOT gate model based on double encoding: study of the errors and physical realizability

Science.gov (United States)

Gueddana, Amor; Attia, Moez; Chatta, Rihab

2015-03-01

In this work, we study the error sources standing behind the non-perfect linear optical quantum components composing a non-deterministic quantum CNOT gate model, which performs the CNOT function with a success probability of 4/27 and uses a double encoding technique to represent photonic qubits at the control and the target. We generalize this model to an abstract probabilistic CNOT version and determine the realizability limits depending on a realistic range of the errors. Finally, we discuss physical constraints allowing the implementation of the Asymmetric Partially Polarizing Beam Splitter (APPBS), which is at the heart of correctly realizing the CNOT function.

Sleep quality, posttraumatic stress, depression, and human errors in train drivers: a population-based nationwide study in South Korea.

Science.gov (United States)

Jeon, Hong Jin; Kim, Ji-Hae; Kim, Bin-Na; Park, Seung Jin; Fava, Maurizio; Mischoulon, David; Kang, Eun-Ho; Roh, Sungwon; Lee, Dongsoo

2014-12-01

Human error is defined as an unintended error that is attributable to humans rather than machines, and that is important to avoid to prevent accidents. We aimed to investigate the association between sleep quality and human errors among train drivers. Cross-sectional. Population-based. A sample of 5,480 subjects who were actively working as train drivers were recruited in South Korea. The participants were 4,634 drivers who completed all questionnaires (response rate 84.6%). None. The Pittsburgh Sleep Quality Index (PSQI), the Center for Epidemiologic Studies Depression Scale (CES-D), the Impact of Event Scale-Revised (IES-R), the State-Trait Anxiety Inventory (STAI), and the Korean Occupational Stress Scale (KOSS). Of 4,634 train drivers, 349 (7.5%) showed more than one human error per 5 y. Human errors were associated with poor sleep quality, higher PSQI total scores, short sleep duration at night, and longer sleep latency. Among train drivers with poor sleep quality, those who experienced severe posttraumatic stress showed a significantly higher number of human errors than those without. Multiple logistic regression analysis showed that human errors were significantly associated with poor sleep quality and posttraumatic stress, whereas there were no significant associations with depression, trait and state anxiety, and work stress after adjusting for age, sex, education years, marital status, and career duration. Poor sleep quality was found to be associated with more human errors in train drivers, especially in those who experienced severe posttraumatic stress. © 2014 Associated Professional Sleep Societies, LLC.

Passive quantum error correction of linear optics networks through error averaging

Science.gov (United States)

Marshman, Ryan J.; Lund, Austin P.; Rohde, Peter P.; Ralph, Timothy C.

2018-02-01

We propose and investigate a method of error detection and noise correction for bosonic linear networks using a method of unitary averaging. The proposed error averaging does not rely on ancillary photons or control and feedforward correction circuits, remaining entirely passive in its operation. We construct a general mathematical framework for this technique and then give a series of proof of principle examples including numerical analysis. Two methods for the construction of averaging are then compared to determine the most effective manner of implementation and probe the related error thresholds. Finally we discuss some of the potential uses of this scheme.

The selective power of causality on memory errors.

Science.gov (United States)

Marsh, Jessecae K; Kulkofsky, Sarah

2015-01-01

We tested the influence of causal links on the production of memory errors in a misinformation paradigm. Participants studied a set of statements about a person, which were presented as either individual statements or pairs of causally linked statements. Participants were then provided with causally plausible and causally implausible misinformation. We hypothesised that studying information connected with causal links would promote representing information in a more abstract manner. As such, we predicted that causal information would not provide an overall protection against memory errors, but rather would preferentially help in the rejection of misinformation that was causally implausible, given the learned causal links. In two experiments, we measured whether the causal linkage of information would be generally protective against all memory errors or only selectively protective against certain types of memory errors. Causal links helped participants reject implausible memory lures, but did not protect against plausible lures. Our results suggest that causal information may promote an abstract storage of information that helps prevent only specific types of memory errors.

Accounting for response misclassification and covariate measurement error improves power and reduces bias in epidemiologic studies.

Science.gov (United States)

Cheng, Dunlei; Branscum, Adam J; Stamey, James D

2010-07-01

To quantify the impact of ignoring misclassification of a response variable and measurement error in a covariate on statistical power, and to develop software for sample size and power analysis that accounts for these flaws in epidemiologic data. A Monte Carlo simulation-based procedure is developed to illustrate the differences in design requirements and inferences between analytic methods that properly account for misclassification and measurement error to those that do not in regression models for cross-sectional and cohort data. We found that failure to account for these flaws in epidemiologic data can lead to a substantial reduction in statistical power, over 25% in some cases. The proposed method substantially reduced bias by up to a ten-fold margin compared to naive estimates obtained by ignoring misclassification and mismeasurement. We recommend as routine practice that researchers account for errors in measurement of both response and covariate data when determining sample size, performing power calculations, or analyzing data from epidemiological studies. 2010 Elsevier Inc. All rights reserved.

Decreasing patient identification band errors by standardizing processes.

Science.gov (United States)

Walley, Susan Chu; Berger, Stephanie; Harris, Yolanda; Gallizzi, Gina; Hayes, Leslie

2013-04-01

Patient identification (ID) bands are an essential component in patient ID. Quality improvement methodology has been applied as a model to reduce ID band errors although previous studies have not addressed standardization of ID bands. Our specific aim was to decrease ID band errors by 50% in a 12-month period. The Six Sigma DMAIC (define, measure, analyze, improve, and control) quality improvement model was the framework for this study. ID bands at a tertiary care pediatric hospital were audited from January 2011 to January 2012 with continued audits to June 2012 to confirm the new process was in control. After analysis, the major improvement strategy implemented was standardization of styles of ID bands and labels. Additional interventions included educational initiatives regarding the new ID band processes and disseminating institutional and nursing unit data. A total of 4556 ID bands were audited with a preimprovement ID band error average rate of 9.2%. Significant variation in the ID band process was observed, including styles of ID bands. Interventions were focused on standardization of the ID band and labels. The ID band error rate improved to 5.2% in 9 months (95% confidence interval: 2.5-5.5; P error rates. This decrease in ID band error rates was maintained over the subsequent 8 months.

A study of the effect of measurement error in predictor variables in nondestructive assay

International Nuclear Information System (INIS)

Burr, Tom L.; Knepper, Paula L.

2000-01-01

It is not widely known that ordinary least squares estimates exhibit bias if there are errors in the predictor variables. For example, enrichment measurements are often fit to two predictors: Poisson-distributed count rates in the region of interest and in the background. Both count rates have at least random variation due to counting statistics. Therefore, the parameter estimates will be biased. In this case, the effect of bias is a minor issue because there is almost no interest in the parameters themselves. Instead, the parameters will be used to convert count rates into estimated enrichment. In other cases, this bias source is potentially more important. For example, in tomographic gamma scanning, there is an emission stage which depends on predictors (the 'system matrix') that are estimated with error during the transmission stage. In this paper, we provide background information for the impact and treatment of errors in predictors, present results of candidate methods of compensating for the effect, review some of the nondestructive assay situations where errors in predictors occurs, and provide guidance for when errors in predictors should be considered in nondestructive assay

Apologies and Medical Error

Science.gov (United States)

2008-01-01

One way in which physicians can respond to a medical error is to apologize. Apologies—statements that acknowledge an error and its consequences, take responsibility, and communicate regret for having caused harm—can decrease blame, decrease anger, increase trust, and improve relationships. Importantly, apologies also have the potential to decrease the risk of a medical malpractice lawsuit and can help settle claims by patients. Patients indicate they want and expect explanations and apologies after medical errors and physicians indicate they want to apologize. However, in practice, physicians tend to provide minimal information to patients after medical errors and infrequently offer complete apologies. Although fears about potential litigation are the most commonly cited barrier to apologizing after medical error, the link between litigation risk and the practice of disclosure and apology is tenuous. Other barriers might include the culture of medicine and the inherent psychological difficulties in facing one’s mistakes and apologizing for them. Despite these barriers, incorporating apology into conversations between physicians and patients can address the needs of both parties and can play a role in the effective resolution of disputes related to medical error. PMID:18972177

Errors in Neonatology

Directory of Open Access Journals (Sweden)

Antonio Boldrini

2013-06-01

Full Text Available Introduction: Danger and errors are inherent in human activities. In medical practice errors can lean to adverse events for patients. Mass media echo the whole scenario. Methods: We reviewed recent published papers in PubMed database to focus on the evidence and management of errors in medical practice in general and in Neonatology in particular. We compared the results of the literature with our specific experience in Nina Simulation Centre (Pisa, Italy. Results: In Neonatology the main error domains are: medication and total parenteral nutrition, resuscitation and respiratory care, invasive procedures, nosocomial infections, patient identification, diagnostics. Risk factors include patients’ size, prematurity, vulnerability and underlying disease conditions but also multidisciplinary teams, working conditions providing fatigue, a large variety of treatment and investigative modalities needed. Discussion and Conclusions: In our opinion, it is hardly possible to change the human beings but it is likely possible to change the conditions under they work. Voluntary errors report systems can help in preventing adverse events. Education and re-training by means of simulation can be an effective strategy too. In Pisa (Italy Nina (ceNtro di FormazIone e SimulazioNe NeonAtale is a simulation center that offers the possibility of a continuous retraining for technical and non-technical skills to optimize neonatological care strategies. Furthermore, we have been working on a novel skill trainer for mechanical ventilation (MEchatronic REspiratory System SImulator for Neonatal Applications, MERESSINA. Finally, in our opinion national health policy indirectly influences risk for errors. Proceedings of the 9th International Workshop on Neonatology · Cagliari (Italy · October 23rd-26th, 2013 · Learned lessons, changing practice and cutting-edge research

Perceived Effects of Prevalent Errors in Contract Documents on Construction Projects

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Oluwaseun Sunday Dosumu

2018-03-01

Full Text Available One of the highly rated causes of poor performance is errors in contract documents. The objectives of this study are to investigate the prevalent errors in contract documents and their effects on construction projects. Questionnaire survey and 51 case study projects (mixed method were adopted for the study. The study also involved the use of Delphi technique to extract the possible errors that may be contained in contract documents; it did not however constitute the empirical data for the study. The sample of the study consists of 985 consulting and 275 contracting firms that engaged in the construction of building projects that were completed between 2013 and 2016 and were above the ground floor. The two-stage stratified random sampling technique was adopted for the study. The data for the study were analysed with descriptive and inferential statistics (based on Shapiro-Wilk’s test. The results of the study indicate that errors in contract documents were moderately prevalent. However, overmeasurement in bill of quantities was prevalent in private, institutional and management procured projects. Traditionally procured projects contain 68% of the errors in contract documents among the procurement methods. Drawings contain the highest number of errors, followed by bill of quantities and specifications. The severe effects of errors in contract documents were structural collapse, deterioration of buildings and contractors’ claims among others. The result of the study implies that, management procurement method is the route to error minimization in developing countries, but it may need to be backed by law and guarded against overmeasurement.

Cultural differences in categorical memory errors persist with age.

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Gutchess, Angela; Boduroglu, Aysecan

2018-01-02

This cross-sectional experiment examined the influence of aging on cross-cultural differences in memory errors. Previous research revealed that Americans committed more categorical memory errors than Turks; we tested whether the cognitive constraints associated with aging impacted the pattern of memory errors across cultures. Furthermore, older adults are vulnerable to memory errors for semantically-related information, and we assessed whether this tendency occurs across cultures. Younger and older adults from the US and Turkey studied word pairs, with some pairs sharing a categorical relationship and some unrelated. Participants then completed a cued recall test, generating the word that was paired with the first. These responses were scored for correct responses or different types of errors, including categorical and semantic. The tendency for Americans to commit more categorical memory errors emerged for both younger and older adults. In addition, older adults across cultures committed more memory errors, and these were for semantically-related information (including both categorical and other types of semantic errors). Heightened vulnerability to memory errors with age extends across cultural groups, and Americans' proneness to commit categorical memory errors occurs across ages. The findings indicate some robustness in the ways that age and culture influence memory errors.

Human errors and mistakes

International Nuclear Information System (INIS)

Wahlstroem, B.

1993-01-01

Human errors have a major contribution to the risks for industrial accidents. Accidents have provided important lesson making it possible to build safer systems. In avoiding human errors it is necessary to adapt the systems to their operators. The complexity of modern industrial systems is however increasing the danger of system accidents. Models of the human operator have been proposed, but the models are not able to give accurate predictions of human performance. Human errors can never be eliminated, but their frequency can be decreased by systematic efforts. The paper gives a brief summary of research in human error and it concludes with suggestions for further work. (orig.)

Measurement-based analysis of error latency. [in computer operating system

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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.

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

International Nuclear Information System (INIS)

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

2000-01-01

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

An Empirical State Error Covariance Matrix Orbit Determination Example

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Frisbee, Joseph H., Jr.

2015-01-01

is suspect. In its most straight forward form, the technique only requires supplemental calculations to be added to existing batch estimation algorithms. In the current problem being studied a truth model making use of gravity with spherical, J2 and J4 terms plus a standard exponential type atmosphere with simple diurnal and random walk components is used. The ability of the empirical state error covariance matrix to account for errors is investigated under four scenarios during orbit estimation. These scenarios are: exact modeling under known measurement errors, exact modeling under corrupted measurement errors, inexact modeling under known measurement errors, and inexact modeling under corrupted measurement errors. For this problem a simple analog of a distributed space surveillance network is used. The sensors in this network make only range measurements and with simple normally distributed measurement errors. The sensors are assumed to have full horizon to horizon viewing at any azimuth. For definiteness, an orbit at the approximate altitude and inclination of the International Space Station is used for the study. The comparison analyses of the data involve only total vectors. No investigation of specific orbital elements is undertaken. The total vector analyses will look at the chisquare values of the error in the difference between the estimated state and the true modeled state using both the empirical and theoretical error covariance matrices for each of scenario.

Deductive Error Diagnosis and Inductive Error Generalization for Intelligent Tutoring Systems.

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Hoppe, H. Ulrich

1994-01-01

Examines the deductive approach to error diagnosis for intelligent tutoring systems. Topics covered include the principles of the deductive approach to diagnosis; domain-specific heuristics to solve the problem of generalizing error patterns; and deductive diagnosis and the hypertext-based learning environment. (Contains 26 references.) (JLB)

GY SAMPLING THEORY IN ENVIRONMENTAL STUDIES 2: SUBSAMPLING ERROR MEASUREMENTS

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Sampling can be a significant source of error in the measurement process. The characterization and cleanup of hazardous waste sites require data that meet site-specific levels of acceptable quality if scientifically supportable decisions are to be made. In support of this effort,...

Hospital medication errors in a pharmacovigilance system in Colombia

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Jorge Enrique Machado-Alba

2015-11-01

Full Text Available Objective: this study analyzes the medication errors reported to a pharmacovigilance system by 26 hospitals for patients in the healthcare system of Colombia. Methods: this retrospective study analyzed the medication errors reported to a systematized database between 1 January 2008 and 12 September 2013. The medication is dispensed by the company Audifarma S.A. to hospitals and clinics around Colombia. Data were classified according to the taxonomy of the National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP. The data analysis was performed using SPSS 22.0 for Windows, considering p-values < 0.05 significant. Results: there were 9 062 medication errors in 45 hospital pharmacies. Real errors accounted for 51.9% (n = 4 707, of which 12.0% (n = 567 reached the patient (Categories C to I and caused harm (Categories E to I to 17 subjects (0.36%. The main process involved in errors that occurred (categories B to I was prescription (n = 1 758, 37.3%, followed by dispensation (n = 1 737, 36.9%, transcription (n = 970, 20.6% and administration (n = 242, 5.1%. The errors in the administration process were 45.2 times more likely to reach the patient (CI 95%: 20.2–100.9. Conclusions: medication error reporting systems and prevention strategies should be widespread in hospital settings, prioritizing efforts to address the administration process.

Task errors by emergency physicians are associated with interruptions, multitasking, fatigue and working memory capacity: a prospective, direct observation study.

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Westbrook, Johanna I; Raban, Magdalena Z; Walter, Scott R; Douglas, Heather

2018-01-09

Interruptions and multitasking have been demonstrated in experimental studies to reduce individuals' task performance. These behaviours are frequently used by clinicians in high-workload, dynamic clinical environments, yet their effects have rarely been studied. To assess the relative contributions of interruptions and multitasking by emergency physicians to prescribing errors. 36 emergency physicians were shadowed over 120 hours. All tasks, interruptions and instances of multitasking were recorded. Physicians' working memory capacity (WMC) and preference for multitasking were assessed using the Operation Span Task (OSPAN) and Inventory of Polychronic Values. Following observation, physicians were asked about their sleep in the previous 24 hours. Prescribing errors were used as a measure of task performance. We performed multivariate analysis of prescribing error rates to determine associations with interruptions and multitasking, also considering physician seniority, age, psychometric measures, workload and sleep. Physicians experienced 7.9 interruptions/hour. 28 clinicians were observed prescribing 239 medication orders which contained 208 prescribing errors. While prescribing, clinicians were interrupted 9.4 times/hour. Error rates increased significantly if physicians were interrupted (rate ratio (RR) 2.82; 95% CI 1.23 to 6.49) or multitasked (RR 1.86; 95% CI 1.35 to 2.56) while prescribing. Having below-average sleep showed a >15-fold increase in clinical error rate (RR 16.44; 95% CI 4.84 to 55.81). WMC was protective against errors; for every 10-point increase on the 75-point OSPAN, a 19% decrease in prescribing errors was observed. There was no effect of polychronicity, workload, physician gender or above-average sleep on error rates. Interruptions, multitasking and poor sleep were associated with significantly increased rates of prescribing errors among emergency physicians. WMC mitigated the negative influence of these factors to an extent. These

VOLUMETRIC ERROR COMPENSATION IN FIVE-AXIS CNC MACHINING CENTER THROUGH KINEMATICS MODELING OF GEOMETRIC ERROR