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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Is the High Probability of Type II Error an Issue in Error Awareness ERP Studies?

Dalile, Boushra January 2016 (has links)
When researchers began addressing the electrophysiology of conscious error awareness more than a decade ago, the role of the error-related negativity (ERN), alongside the subsequently occurring error positivity (Pe), was an obvious locus of attention given the fact that they are taken as indices of cortical error processing. In contrast to the clear-cut findings that link the amplitude of the Pe to error awareness, the association between the ERN amplitude and error awareness is vastly unclear, with a range of studies reporting significant differences in the ERN amplitude with respect to error awareness, while others observing no modulation of the ERN amplitude. One problem in the studies obtaining null findings is the fact that conclusions are drawn based on small sample sizes, increasing the probability of type II error, especially given the fact that the ERN elicited using various error awareness paradigms tends to be small. The aim of the present study was to therefore address the issue of type II error in order to draw more certain conclusions about the modulation of the ERN amplitude by conscious error awareness. Forty participants performed a manual response inhibition task optimised to examine error awareness. While the early and late Pe amplitudes showed the expected sensitivity to error awareness, the ERN results depicted a more complex picture. The ERN amplitude for unaware errors appeared more negative than that of aware errors, both numerically and on the grand average ERP. The unexpected findings were explained in terms of (a) latency issues in the present data, (b) characteristics of the manual response inhibition task used and the possibility that it elicits variation in neurocognitive processing, and (c), in relation to possible contamination by the contingent negative variation (CNV), an ERP component elicited during response preparation. Suggestions for future research on how to address the issues raised in the present paper are also discussed.
12

Using task network modeling to predict human error

Pop, Vlad L. 07 January 2016 (has links)
Human error taxonomies have been implemented in numerous safety critical industries. These taxonomies have provided invaluable insight into understanding the underlying causes of human error; however, their utility for actually predicting future errors remains in question. A need has been identified for another approach to supplement what we can extrapolate from taxonomies and better predict human error. Task network modeling is a promising approach to human error prediction that had yet to be empirically evaluated. This study tested a task network modeling approach to predicting human error in the context of automotive assembly. The task network modeling architecture was expanded to include a set of predictors from the human error literature, and used to model part of an operational automotive assembly plant. This manuscript contains three studies. Study 1 tested separate task network models for two different target areas of an active automotive assembly line. Study 2 tested the validity of predictions made by the models from Study 1, both within and across samples. Study 3 tested predictions across both models on a larger sample of vehicles. The expanded architecture accounted for 21.9% to 36.5% of the variance in human error and identified 12 explanatory variables that significantly predicted the occurrence of human error. Model outputs were used to compute prediction equations that were tested using binary logistic regression and then cross-validated twice using both split-half and cross-sample validation. The predictors of Time Pressure, Visual Workload, Auditory Workload, Cognitive Workload, Psychomotor Workload, Task Frequency, Information Flow, Teamwork, and Equipment Feedback were significant predictors of human error in all three models that were tested. The variables of Information Presentation and Task Dependency varied in significance across samples, but both were significant in two out of the three models. The variables of Shift and Hour into Shift were never significant in any of the three models. The variables that were greatly stable across studies were all related to the tasks being performed by each worker at each station. The variables related to the timing of errors, on the other hand, were never significant. The results indicate that an expanded task network architecture is a great tool for predicting the situations and circumstances in which human errors will occur, but not the timing of when they will occur. Nevertheless, task network modeling demonstrated to provide useful, valid, and accurate predictions of human error and should continue to be developed as an error prediction tool.
13

Predicting realistic performance rate and optimum inspection rate in construction

Saha, Swapan, University of Western Sydney, College of Law and Business, School of Construction, Property and Planning January 2002 (has links)
This study has been concerned with investigating several aspects of error, including human error, and the underlying causes in construction.It has attempted to calculate the realistic error rate and as a result has identified the optimum inspection rate in construction.Error prediction in construction is a new field of study, particularly with regard to repetitive construction processes.Several methodologies and probalistic approaches have been considered.Case studies have been presented and the findings shown. The results from several publications suggest that the learning rate varies with experience and with the skill of the worker, task complexity, environmental factors and interruptions due to inclement weather, inspection delays, and equipment breakdowns.A learning theory using a Straight-Line Power model was used to predict future performances,and the descrete event simulation model using 'iThink' simulation software,in conjunction with CPM, was developed in this study to calculate project durations.A simulation model was developed using the Event Tree Analysis (ETA) to calculate a more realistic error rate for the repetitive tasks. / Doctor of Philosophy (PhD)
14

Relationen och beteendets inverkan på observatörens skattningar av aktörens beteende : Skattas vännen alltid som vänligare än främlingen?

Klinga, Karolina January 2008 (has links)
<p><!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --><p>Människan har en tydlig tendens att begå det fundamentala attributionsfelet, det vill säga överskatta personlighetsbundna faktorer vid förklarandet av andras beteende. Den aktuella undersökningen genomfördes på en högskola i Mellansverige. Deltagarna fick besvara en enkät utformad i sex olika varianter där betingelserna beteende och person manipulerades. Den aktuella studien visade att fundamentala attributionsfelet till en viss del påverkas av relationer och typ av beteende. En person som utför ett positivt beteende skattas som vänligare och snällare än en person som utför ett negativt beteende. Likaså skattas en väns personlighet som vänligare än en ej omtyckt bekants och en främlings personlighet. Dessa resultat väcker intresset för ytterligare studier om hur relationer påverkar människans uppfattning om individen i andra situationer.</p></p>
15

Relationen och beteendets inverkan på observatörens skattningar av aktörens beteende : Skattas vännen alltid som vänligare än främlingen?

Klinga, Karolina January 2008 (has links)
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->Människan har en tydlig tendens att begå det fundamentala attributionsfelet, det vill säga överskatta personlighetsbundna faktorer vid förklarandet av andras beteende. Den aktuella undersökningen genomfördes på en högskola i Mellansverige. Deltagarna fick besvara en enkät utformad i sex olika varianter där betingelserna beteende och person manipulerades. Den aktuella studien visade att fundamentala attributionsfelet till en viss del påverkas av relationer och typ av beteende. En person som utför ett positivt beteende skattas som vänligare och snällare än en person som utför ett negativt beteende. Likaså skattas en väns personlighet som vänligare än en ej omtyckt bekants och en främlings personlighet. Dessa resultat väcker intresset för ytterligare studier om hur relationer påverkar människans uppfattning om individen i andra situationer.
16

Measurement Error in Designed Experiments for Second Order Models

McMahan, Angela Renee 11 April 1997 (has links)
Measurement error (ME) in the factor levels of designed experiments is often overlooked in the planning and analysis of experimental designs. A familiar model for this type of ME, called the Berkson error model, is discussed at length. Previous research has examined the effect of Berkson error on two-level factorial and fractional factorial designs. This dissertation extends the examination to designs for second order models. The results are used to suggest optimal values for axial points in Central Composite Designs. The proper analysis for experimental data including ME is outlined for first and second order models. A comparison of this analysis to a typical Ordinary Least Squares analysis is made for second order models. The comparison is used to quantify the difference in performance of the two methods, both of which yield unbiased coefficient estimates. Robustness to misspecification of the ME variance is also explored. A solution for experimental planning is also suggested. A design optimality criterion, called the DME criterion, is used to create a second-stage design when ME is present. The performance of the criterion is compared to a D-optimal design augmentation. A final comparison is made between methods accounting for ME and methods ignoring ME. / Ph. D.
17

Residual-Based Discretization Error Estimation for Unsteady Flows

Gautham, Tejaswini 10 January 2020 (has links)
Computational fluid dynamics (CFD) is a tool that is widely used in most industries today. It is important to have rigorous techniques to estimate the error produced when using CFD. This thesis develops techniques to estimate discretization error for unsteady flows using the unsteady error transport equation (ETE) as well as defect correction. A framework to obtain exact truncation error and estimated truncation error is also presented. The technique and results for the steady-state cases are given and the algorithm used for the steady case is extended for the unsteady case. Numerical results are presented for the steady viscous Burgers' equation, unsteady viscous Burgers' equation, steady quasi-1D Euler equations, and unsteady 1D Euler equations when applied to a shock tube. Cases using either defect correction or ETE are shown to give higher orders of accuracy for the corrected discretization error estimates when compared to the discretization error of the primal solution. / Master of Science / Computational fluid dynamics (CFD) is a tool that is widely used in most industries today. It is used to understand complex flows that are difficult to replicate using experimental techniques or by theoretical methods. It is important to have rigorous techniques to estimate the error produced when using CFD even when the exact solution is not available for comparison. This paper develops techniques to estimate discretization error for unsteady flows. Discretization error has one of the largest error magnitudes in CFD solutions. The exact physics dictates the use of continuous equations but to apply CFD techniques, the continuous equations have to be converted to discrete equations. Truncation error is, the error obtained when converting the continuous equations to discrete equations. This truncation error is in turn, the local source term for discretization error. To reduce the discretization error in the discrete equations, the exact or estimated truncation error is either added as a source term to the discrete equations or is used along with the error transport equation to get a better estimate of the solutions. A framework to obtain exact truncation error and estimated truncation error is also presented. The framework is first applied to the steady equations and is verified with results from previous studies and is then extended to the unsteady flows.
18

The error in moral discourse and what to do about it

Brown, Philip Daniel January 2011 (has links)
Moral error theory is the thesis that statements attributing moral properties to objects are always untrue. In my thesis I have two aims: to argue for error theory and defend it from a number of objections (chapters 1 and 2); and to consider whether and how we should go on with moral discourse, if we come to accept error theory (chapters 3 and 4). In the first chapter I argue for error theory by defending a number of metaethical theses which taken together reveal that sincere utterances of indicative moral sentences commit us to ‘objectively prescriptive values’. I then go on to defend the arguments of J.L. Mackie and Richard Joyce that such values do not exist, and thus indicative moral sentences are systematically untrue. In the second chapter I deal with five objections to error theory: (i) error theory is self-undermining; (ii) error theory defies commonsense; (iii) error theory is defeated by a modal counter argument; (iv) moral error theory entails an absurd epistemic error theory; (v) the error theorist’s denial that there are any categorical imperatives is untenable, as it is constitutive of being a rational agent that one is guided by certain categorical norms. I show how each of these objections can be dealt with. In the third chapter I begin to look at what we should do with moral discourse once we have accepted error theory. The main foci of this chapter are eliminativism (the thesis that we ought to stop engaging in moral discourse) and reformist realism (the thesis that we should modify the semantics of moral discourse so that our moral terms can successfully refer). I argue that the rationales that have been provided for eliminativism, such as that moral societies are harmful to most of their members, and that it always harmful to make untrue judgements, are unpersuasive. I consider the most plausible way of being a reformist realist is to argue that we should become moral relativists, but I argue that such a move would be unstable and we would revert to non-relativist type. In the fourth chapter I focus on moral fictionalism (the thesis that we should continue to use indicative moral sentences, while adopting some attitude to them other than belief). One of the more interesting motivations that has been offered for moral fictionalism is that moral discourse either facilitates or is essential for some non-moral description. I find no evidence for the stronger claim, but argue that there is some plausibility in the weaker claim. Another interesting suggestion (made by Joyce) is that pretending that certain actions are morally required or forbidden will help motivate prudent behaviour. I argue that although it is very plausible that thinking in moral terms can motivate prudent behaviour, Joyce fails to provide a convincing argument that we can retain these positive motivational effects if we abandon moral belief. In light of this, I argue that the only way for error theorists to retain the positive motivational aspect of moral discourse is by becoming conservationists. The conservationist argues that we can and should continue to form and be guided by genuine moral beliefs, even if we have become convinced of the error theory. Naturally, conservationism is open to a variety of objections, and I deal with the ones that seem most pressing.
19

Design of run-length limited partial unit memory codes for digital magnetic recording and trellis coded quantisation based on PUM codes

Thayananthan, V. January 1998 (has links)
No description available.
20

Trellis decoding techniques for array codes

Kaya, Lami January 1993 (has links)
No description available.

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