Core Reactor Calculation Using the Adaptive Remeshing with a Current Error Estimator

With the objective to improve the reactor physics calculation on a 2D and 3D nuclear reactor via the Diffusion Equation, an adaptive automatic finite element remeshing method, based on the elementary area (2D) or volume (3D) constraints, has been developed. The adaptive remeshing technique, guided by a posteriori error estimator, makes use of two external mesh generator programs: Triangle and TetGen. The use of these free external finite element mesh generators and an adaptive remeshing technique based on the current field continuity show that they are powerful tools to improve the neutron flux distribution calculation and by consequence the power solution of the reactor core even though they have a minor influence on the critical coefficient of the calculated reactor core examples. Two numerical examples are presented: the 2D IAEA reactor core numerical benchmark and the 3D model of the Argonauta research reactor, built in Brasil.

Error Recovery Performance: The Impact of Leader Behavioral Integrity and Job Satisfaction

This article introduces the concept of error recovery performance, followed by the development and validation of an instrument to measure it. The first objective of this article is to broaden the current concept of service recovery to be relevant to the back-of-house operations. The second objective is to examine the influence of leader behavioral integrity (BI) on error recovery performance. Moreover, the study examines the mediating effect of job satisfaction between BI and error recovery performance. Finally, the study links error management performance with work-unit effectiveness. Data for Study 1 were collected from 369 hotel employees in Turkey. The same relationships were tested again in Study 2 to validate the findings of Study 1 with a different sample. Data for Study 2 were collected from 33 departmental managers from the same hotels. Linear regression analysis was used to test the direct effects. The mediating effects were tested using the mediation test suggested by Preacher and Hayes. In addition, in Study 2, general managers of the hotels were asked to rate the effectiveness of each manager and their respective department. Results from Study 1 indicate that BI drives error recovery performance, and this impact is mediated by employee job satisfaction. Results of Study 2 confirm this model and finds further that managers’ self-rated error recovery performance was associated with their general managers’ assessment of their deliverables and of their department’s overall performance.

Designing Out Medical Error, WCDH Boston 2011

This talk is about using research and design to reduce medical errors. It doesn’t matter whether you deliver healthcare in the old-fashioned pathogenic way, or salutogenically, it all falls apart if systems and protocols let the patient down, and harm them.

A posteriori error estimation for discontinuous Galerkin discretizations of H(curl)-elliptic partial differential equations

We develop the a posteriori error estimation of interior penalty discontinuous Galerkin discretizations for H(curl)-elliptic problems that arise in eddy current models. Computable upper and lower bounds on the error measured in terms of a natural (mesh-dependent) energy norm are derived. The proposed a posteriori error estimator is validated by numerical experiments, illustrating its reliability and efficiency for a range of test problems.

Symmetric Interior Penalty DG Methods for the Compressible Navier-Stokes Equations II: Goal--Oriented A Posteriori Error Estimation

In this article we consider the application of the generalization of the symmetric version of the interior penalty discontinuous Galerkin finite element method to the numerical approximation of the compressible Navier--Stokes equations. In particular, we consider the a posteriori error analysis and adaptive mesh design for the underlying discretization method. Indeed, by employing a duality argument (weighted) Type I a posteriori bounds are derived for the estimation of the error measured in terms of general target functionals of the solution; these error estimates involve the product of the finite element residuals with local weighting terms involving the solution of a certain dual problem that must be numerically approximated. This general approach leads to the design of economical finite element meshes specifically tailored to the computation of the target functional of interest, as well as providing efficient error estimation. Numerical experiments demonstrating the performance of the proposed approach will be presented.

El error en el uso de los números racionales e irracionales, como evidencia de obstáculo epistemológico, en estudiantes del grado noveno

En este trabajo se hace una reflexión crítica acerca de los errores en el uso y manejo de los números racionales e irracionales, en estudiantes del grado noveno de dos instituciones educativas de Antioquia, y las consecuentes dificultades que estos generan en la construcción de los números reales, se hace necesaria para detectarlos, identificarlos y categorizarlos de manera sistemática con la taxonomía realizada por Radatz, esto con el propósito de generar reflexiones en vía de la comprensión del aprendizaje y de la enseñanza de los mismos, en la etapa escolar y de futuras propuestas didácticas. La reflexión se fundamenta en la noción de obstáculo epistemológico dada por Gastón Bachelard y extrapolada a la Didáctica de la matemática por Guy Brousseau y Luis Rico entre otros, dando cuenta de lo problemático que resulta el aprendizaje de los números racionales e irracionales, no como resultado de la incapacidad o ignorancia manifiesta en los estudiantes; sino más bien, como evidencia de posibles obstáculos epistemológicos, propios de la construcción conceptual de dichos números, que pueden ser rastreados a lo largo de la historia y que fueron detectados en el presente trabajo por errores repetitivos y persistentes en el uso que hacen los estudiantes de ellos cuando realizan actividades específicas con ellos en el aula de clase, sin descartar que en muchas ocasiones se encuentran entremezclados con obstáculos de tipo didáctico.

Error correcting codes for visible light communication systems

Over the past few years, the number of wireless networks users has been increasing. Until now, Radio-Frequency (RF) used to be the dominant technology. However, the electromagnetic spectrum in these region is being saturated, demanding for alternative wireless technologies. Recently, with the growing market of LED lighting, the Visible Light Communications has been drawing attentions from the research community. First, it is an eficient device for illumination. Second, because of its easy modulation and high bandwidth. Finally, it can combine illumination and communication in the same device, in other words, it allows to implement highly eficient wireless communication systems. One of the most important aspects in a communication system is its reliability when working in noisy channels. In these scenarios, the received data can be afected by errors. In order to proper system working, it is usually employed a Channel Encoder in the system. Its function is to code the data to be transmitted in order to increase system performance. It commonly uses ECC, which appends redundant information to the original data. At the receiver side, the redundant information is used to recover the erroneous data. This dissertation presents the implementation steps of a Channel Encoder for VLC. It was consider several techniques such as Reed-Solomon and Convolutional codes, Block and Convolutional Interleaving, CRC and Puncturing. A detailed analysis of each technique characteristics was made in order to choose the most appropriate ones. Simulink models were created in order to simulate how diferent codes behave in diferent scenarios. Later, the models were implemented in a FPGA and simulations were performed. Hardware co-simulations were also implemented to faster simulation results. At the end, diferent techniques were combined to create a complete Channel Encoder capable of detect and correct random and burst errors, due to the usage of a RS(255,213) code with a Block Interleaver. Furthermore, after the decoding process, the proposed system can identify uncorrectable errors in the decoded data due to the CRC-32 algorithm.

Social Influences of Error Monitoring

Adolescence is characterized by dramatic hormonal, physical, and psychological changes, and is a period of risk for affective and anxiety disorders. Pubertal development during adolescence plays a major role in the emergence of these disorders, particularly among girls. Thus, it is critical to identify early biomarkers of risk. One potential biomarker, the error-related negativity (ERN), is an event-related potential following an erroneous response. Individuals with an anxiety disorder demonstrate a greater ERN than healthy comparisons, an association which is stronger in adolescence, suggesting that pubertal development may play a role in the ERN as a predictor of anxiety. One form of anxiety often observed in adolescence, particularly among girls, is social anxiety, which is defined as anxiety elicited by social-evaluative contexts. In adults, enhancements of the ERN in social-evaluative contexts is positively related to social anxiety symptoms, suggesting that the ERN in social contexts may serve as a biomarker for social anxiety. This dissertation examined the ERN in and its relation with puberty and social anxiety among 76 adolescent girls. Adolescent girls completed a flanker task in two different

Development of error correction techniques for nitrate-N load estimation models

Excess nutrient loads carried by streams and rivers are a great concern for environmental resource managers. In agricultural regions, excess loads are transported downstream to receiving water bodies, potentially causing algal blooms, which could lead to numerous ecological problems. To better understand nutrient load transport, and to develop appropriate water management plans, it is important to have accurate estimates of annual nutrient loads. This study used a Monte Carlo sub-sampling method and error-corrected statistical models to estimate annual nitrate-N loads from two watersheds in central Illinois. The performance of three load estimation methods (the seven-parameter log-linear model, the ratio estimator, and the flow-weighted averaging estimator) applied at one-, two-, four-, six-, and eight-week sampling frequencies were compared. Five error correction techniques; the existing composite method, and four new error correction techniques developed in this study; were applied to each combination of sampling frequency and load estimation method. On average, the most accurate error reduction technique, (proportional rectangular) resulted in 15% and 30% more accurate load estimates when compared to the most accurate uncorrected load estimation method (ratio estimator) for the two watersheds. Using error correction methods, it is possible to design more cost-effective monitoring plans by achieving the same load estimation accuracy with fewer observations. Finally, the optimum combinations of monitoring threshold and sampling frequency that minimizes the number of samples required to achieve specified levels of accuracy in load estimation were determined. For one- to three-weeks sampling frequencies, combined threshold/fixed-interval monitoring approaches produced the best outcomes, while fixed-interval-only approaches produced the most accurate results for four- to eight-weeks sampling frequencies.