Liquefied Bleed for Stability and Efficiency of High Speed Inlets

NASA Technical Reports Server (NTRS)

Saunders, J. David; Davis, David; Barsi, Stephen J.; Deans, Matthew C.; Weir, Lois J.; Sanders, Bobby W.

2014-01-01

A mission analysis code was developed to perform a trade study on the effectiveness of liquefying bleed for the inlet of the first stage of a TSTO vehicle. By liquefying bleed, the vehicle weight (TOGW) could be reduced by 7 to 23%. Numerous simplifying assumptions were made and lessons were learned. Increased accuracy in future analyses can be achieved by: Including a higher fidelity model to capture the effect of rescaling (variable vehicle TOGW). Refining specific thrust and impulse models ( T m a and Isp) to preserve fuel-to-air ratio. Implementing LH2 for T m a and Isp. Correlating baseline design to other mission analyses and correcting vehicle design elements. Implementing angle-of-attack effects on inlet characteristics. Refining aerodynamic performance (to improve L/D ratio at higher Mach numbers). Examining the benefit with partial cooling or densification of the bleed air stream. Incorporating higher fidelity weight estimates for the liquefied bleed system (heat exchange and liquid storage versus bleed duct weights) could be added when more fully developed. Adding trim drag or 6-degree-of-freedom trajectory analysis for higher fidelity. Investigating vehicle optimization for each of the bleed configurations.

The Lévy flight foraging hypothesis: forgetting about memory may lead to false verification of Brownian motion.

PubMed

Gautestad, Arild O; Mysterud, Atle

2013-01-01

The Lévy flight foraging hypothesis predicts a transition from scale-free Lévy walk (LW) to scale-specific Brownian motion (BM) as an animal moves from resource-poor towards resource-rich environment. However, the LW-BM continuum implies a premise of memory-less search, which contradicts the cognitive capacity of vertebrates. We describe methods to test if apparent support for LW-BM transitions may rather be a statistical artifact from movement under varying intensity of site fidelity. A higher frequency of returns to previously visited patches (stronger site fidelity) may erroneously be interpreted as a switch from LW towards BM. Simulations of scale-free, memory-enhanced space use illustrate how the ratio between return events and scale-free exploratory movement translates to varying strength of site fidelity. An expanded analysis of GPS data of 18 female red deer, Cervus elaphus, strengthens previous empirical support of memory-enhanced and scale-free space use in a northern forest ecosystem. A statistical mechanical model architecture that describes foraging under environment-dependent variation of site fidelity may allow for higher realism of optimal search models and movement ecology in general, in particular for vertebrates with high cognitive capacity.

First-Order Model Management With Variable-Fidelity Physics Applied to Multi-Element Airfoil Optimization

NASA Technical Reports Server (NTRS)

Alexandrov, N. M.; Nielsen, E. J.; Lewis, R. M.; Anderson, W. K.

2000-01-01

First-order approximation and model management is a methodology for a systematic use of variable-fidelity models or approximations in optimization. The intent of model management is to attain convergence to high-fidelity solutions with minimal expense in high-fidelity computations. The savings in terms of computationally intensive evaluations depends on the ability of the available lower-fidelity model or a suite of models to predict the improvement trends for the high-fidelity problem, Variable-fidelity models can be represented by data-fitting approximations, variable-resolution models. variable-convergence models. or variable physical fidelity models. The present work considers the use of variable-fidelity physics models. We demonstrate the performance of model management on an aerodynamic optimization of a multi-element airfoil designed to operate in the transonic regime. Reynolds-averaged Navier-Stokes equations represent the high-fidelity model, while the Euler equations represent the low-fidelity model. An unstructured mesh-based analysis code FUN2D evaluates functions and sensitivity derivatives for both models. Model management for the present demonstration problem yields fivefold savings in terms of high-fidelity evaluations compared to optimization done with high-fidelity computations alone.

Gravity Modeling for Variable Fidelity Environments

NASA Technical Reports Server (NTRS)

Madden, Michael M.

2006-01-01

Aerospace simulations can model worlds, such as the Earth, with differing levels of fidelity. The simulation may represent the world as a plane, a sphere, an ellipsoid, or a high-order closed surface. The world may or may not rotate. The user may select lower fidelity models based on computational limits, a need for simplified analysis, or comparison to other data. However, the user will also wish to retain a close semblance of behavior to the real world. The effects of gravity on objects are an important component of modeling real-world behavior. Engineers generally equate the term gravity with the observed free-fall acceleration. However, free-fall acceleration is not equal to all observers. To observers on the sur-face of a rotating world, free-fall acceleration is the sum of gravitational attraction and the centrifugal acceleration due to the world's rotation. On the other hand, free-fall acceleration equals gravitational attraction to an observer in inertial space. Surface-observed simulations (e.g. aircraft), which use non-rotating world models, may choose to model observed free fall acceleration as the gravity term; such a model actually combines gravitational at-traction with centrifugal acceleration due to the Earth s rotation. However, this modeling choice invites confusion as one evolves the simulation to higher fidelity world models or adds inertial observers. Care must be taken to model gravity in concert with the world model to avoid denigrating the fidelity of modeling observed free fall. The paper will go into greater depth on gravity modeling and the physical disparities and synergies that arise when coupling specific gravity models with world models.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glascoe, Lee; Gowardhan, Akshay; Lennox, Kristin

In the interest of promoting the international exchange of technical expertise, the US Department of Energy’s Office of Emergency Operations (NA-40) and the French Commissariat à l'Energie Atomique et aux énergies alternatives (CEA) requested that the National Atmospheric Release Advisory Center (NARAC) of Lawrence Livermore National Laboratory (LLNL) in Livermore, California host a joint table top exercise with experts in emergency management and atmospheric transport modeling. In this table top exercise, LLNL and CEA compared each other’s flow and dispersion models. The goal of the comparison is to facilitate the exchange of knowledge, capabilities, and practices, and to demonstrate themore » utility of modeling dispersal at different levels of computational fidelity. Two modeling approaches were examined, a regional scale modeling approach, appropriate for simple terrain and/or very large releases, and an urban scale modeling approach, appropriate for small releases in a city environment. This report is a summary of LLNL and CEA modeling efforts from this exercise. Two different types of LLNL and CEA models were employed in the analysis: urban-scale models (Aeolus CFD at LLNL/NARAC and Parallel- Micro-SWIFT-SPRAY, PMSS, at CEA) for analysis of a 5,000 Ci radiological release and Lagrangian Particle Dispersion Models (LODI at LLNL/NARAC and PSPRAY at CEA) for analysis of a much larger (500,000 Ci) regional radiological release. Two densely-populated urban locations were chosen: Chicago with its high-rise skyline and gridded street network and Paris with its more consistent, lower building height and complex unaligned street network. Each location was considered under early summer daytime and nighttime conditions. Different levels of fidelity were chosen for each scale: (1) lower fidelity mass-consistent diagnostic, intermediate fidelity Navier-Stokes RANS models, and higher fidelity Navier-Stokes LES for urban-scale analysis, and (2) lower-fidelity single-profile meteorology versus higher-fidelity three-dimensional gridded weather forecast for regional-scale analysis. Tradeoffs between computation time and the fidelity of the results are discussed for both scales. LES, for example, requires nearly 100 times more processor time than the mass-consistent diagnostic model or the RANS model, and seems better able to capture flow entrainment behind tall buildings. As anticipated, results obtained by LLNL and CEA at regional scale around Chicago and Paris look very similar in terms of both atmospheric dispersion of the radiological release and total effective dose. Both LLNL and CEA used the same meteorological data, Lagrangian particle dispersion models, and the same dose coefficients. LLNL and CEA urban-scale modeling results show consistent phenomenological behavior and predict similar impacted areas even though the detailed 3D flow patterns differ, particularly for the Chicago cases where differences in vertical entrainment behind tall buildings are particularly notable. Although RANS and LES (LLNL) models incorporate more detailed physics than do mass-consistent diagnostic flow models (CEA), it is not possible to reach definite conclusions about the prediction fidelity of the various models as experimental measurements were not available for comparison. Stronger conclusions about the relative performances of the models involved and evaluation of the tradeoffs involved in model simplification could be made with a systematic benchmarking of urban-scale modeling. This could be the purpose of a future US / French collaborative exercise.« less

A multi-fidelity framework for physics based rotor blade simulation and optimization

NASA Astrophysics Data System (ADS)

Collins, Kyle Brian

New helicopter rotor designs are desired that offer increased efficiency, reduced vibration, and reduced noise. Rotor Designers in industry need methods that allow them to use the most accurate simulation tools available to search for these optimal designs. Computer based rotor analysis and optimization have been advanced by the development of industry standard codes known as "comprehensive" rotorcraft analysis tools. These tools typically use table look-up aerodynamics, simplified inflow models and perform aeroelastic analysis using Computational Structural Dynamics (CSD). Due to the simplified aerodynamics, most design studies are performed varying structural related design variables like sectional mass and stiffness. The optimization of shape related variables in forward flight using these tools is complicated and results are viewed with skepticism because rotor blade loads are not accurately predicted. The most accurate methods of rotor simulation utilize Computational Fluid Dynamics (CFD) but have historically been considered too computationally intensive to be used in computer based optimization, where numerous simulations are required. An approach is needed where high fidelity CFD rotor analysis can be utilized in a shape variable optimization problem with multiple objectives. Any approach should be capable of working in forward flight in addition to hover. An alternative is proposed and founded on the idea that efficient hybrid CFD methods of rotor analysis are ready to be used in preliminary design. In addition, the proposed approach recognizes the usefulness of lower fidelity physics based analysis and surrogate modeling. Together, they are used with high fidelity analysis in an intelligent process of surrogate model building of parameters in the high fidelity domain. Closing the loop between high and low fidelity analysis is a key aspect of the proposed approach. This is done by using information from higher fidelity analysis to improve predictions made with lower fidelity models. This thesis documents the development of automated low and high fidelity physics based rotor simulation frameworks. The low fidelity framework uses a comprehensive code with simplified aerodynamics. The high fidelity model uses a parallel processor capable CFD/CSD methodology. Both low and high fidelity frameworks include an aeroacoustic simulation for prediction of noise. A synergistic process is developed that uses both the low and high fidelity frameworks together to build approximate models of important high fidelity metrics as functions of certain design variables. To test the process, a 4-bladed hingeless rotor model is used as a baseline. The design variables investigated include tip geometry and spanwise twist distribution. Approximation models are built for metrics related to rotor efficiency and vibration using the results from 60+ high fidelity (CFD/CSD) experiments and 400+ low fidelity experiments. Optimization using the approximation models found the Pareto Frontier anchor points, or the design having maximum rotor efficiency and the design having minimum vibration. Various Pareto generation methods are used to find designs on the frontier between these two anchor designs. When tested in the high fidelity framework, the Pareto anchor designs are shown to be very good designs when compared with other designs from the high fidelity database. This provides evidence that the process proposed has merit. Ultimately, this process can be utilized by industry rotor designers with their existing tools to bring high fidelity analysis into the preliminary design stage of rotors. In conclusion, the methods developed and documented in this thesis have made several novel contributions. First, an automated high fidelity CFD based forward flight simulation framework has been built for use in preliminary design optimization. The framework was built around an integrated, parallel processor capable CFD/CSD/AA process. Second, a novel method of building approximate models of high fidelity parameters has been developed. The method uses a combination of low and high fidelity results and combines Design of Experiments, statistical effects analysis, and aspects of approximation model management. And third, the determination of rotor blade shape variables through optimization using CFD based analysis in forward flight has been performed. This was done using the high fidelity CFD/CSD/AA framework and method mentioned above. While the low and high fidelity predictions methods used in the work still have inaccuracies that can affect the absolute levels of the results, a framework has been successfully developed and demonstrated that allows for an efficient process to improve rotor blade designs in terms of a selected choice of objective function(s). Using engineering judgment, this methodology could be applied today to investigate opportunities to improve existing designs. With improvements in the low and high fidelity prediction components that will certainly occur, this framework could become a powerful tool for future rotorcraft design work. (Abstract shortened by UMI.)

Initial Integration of Noise Prediction Tools for Acoustic Scattering Effects

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Burley, Casey L.; Tinetti, Ana; Rawls, John W.

2008-01-01

This effort provides an initial glimpse at NASA capabilities available in predicting the scattering of fan noise from a non-conventional aircraft configuration. The Aircraft NOise Prediction Program, Fast Scattering Code, and the Rotorcraft Noise Model were coupled to provide increased fidelity models of scattering effects on engine fan noise sources. The integration of these codes led to the identification of several keys issues entailed in applying such multi-fidelity approaches. In particular, for prediction at noise certification points, the inclusion of distributed sources leads to complications with the source semi-sphere approach. Computational resource requirements limit the use of the higher fidelity scattering code to predict radiated sound pressure levels for full scale configurations at relevant frequencies. And, the ability to more accurately represent complex shielding surfaces in current lower fidelity models is necessary for general application to scattering predictions. This initial step in determining the potential benefits/costs of these new methods over the existing capabilities illustrates a number of the issues that must be addressed in the development of next generation aircraft system noise prediction tools.

High-Fidelity Micromechanics Model Developed for the Response of Multiphase Materials

NASA Technical Reports Server (NTRS)

Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, Steven M.

2002-01-01

A new high-fidelity micromechanics model has been developed under funding from the NASA Glenn Research Center for predicting the response of multiphase materials with arbitrary periodic microstructures. The model's analytical framework is based on the homogenization technique, but the method of solution for the local displacement and stress fields borrows concepts previously employed in constructing the higher order theory for functionally graded materials. The resulting closed-form macroscopic and microscopic constitutive equations, valid for both uniaxial and multiaxial loading of periodic materials with elastic and inelastic constitutive phases, can be incorporated into a structural analysis computer code. Consequently, this model now provides an alternative, accurate method.

High fidelity simulations of infrared imagery with animated characters

NASA Astrophysics Data System (ADS)

Näsström, F.; Persson, A.; Bergström, D.; Berggren, J.; Hedström, J.; Allvar, J.; Karlsson, M.

2012-06-01

High fidelity simulations of IR signatures and imagery tend to be slow and do not have effective support for animation of characters. Simplified rendering methods based on computer graphics methods can be used to overcome these limitations. This paper presents a method to combine these tools and produce simulated high fidelity thermal IR data of animated people in terrain. Infrared signatures for human characters have been calculated using RadThermIR. To handle multiple character models, these calculations use a simplified material model for the anatomy and clothing. Weather and temperature conditions match the IR-texture used in the terrain model. The calculated signatures are applied to the animated 3D characters that, together with the terrain model, are used to produce high fidelity IR imagery of people or crowds. For high level animation control and crowd simulations, HLAS (High Level Animation System) has been developed. There are tools available to create and visualize skeleton based animations, but tools that allow control of the animated characters on a higher level, e.g. for crowd simulation, are usually expensive and closed source. We need the flexibility of HLAS to add animation into an HLA enabled sensor system simulation framework.

Nonlinear information fusion algorithms for data-efficient multi-fidelity modelling.

PubMed

Perdikaris, P; Raissi, M; Damianou, A; Lawrence, N D; Karniadakis, G E

2017-02-01

Multi-fidelity modelling enables accurate inference of quantities of interest by synergistically combining realizations of low-cost/low-fidelity models with a small set of high-fidelity observations. This is particularly effective when the low- and high-fidelity models exhibit strong correlations, and can lead to significant computational gains over approaches that solely rely on high-fidelity models. However, in many cases of practical interest, low-fidelity models can only be well correlated to their high-fidelity counterparts for a specific range of input parameters, and potentially return wrong trends and erroneous predictions if probed outside of their validity regime. Here we put forth a probabilistic framework based on Gaussian process regression and nonlinear autoregressive schemes that is capable of learning complex nonlinear and space-dependent cross-correlations between models of variable fidelity, and can effectively safeguard against low-fidelity models that provide wrong trends. This introduces a new class of multi-fidelity information fusion algorithms that provide a fundamental extension to the existing linear autoregressive methodologies, while still maintaining the same algorithmic complexity and overall computational cost. The performance of the proposed methods is tested in several benchmark problems involving both synthetic and real multi-fidelity datasets from computational fluid dynamics simulations.

Gaussian functional regression for output prediction: Model assimilation and experimental design

NASA Astrophysics Data System (ADS)

Nguyen, N. C.; Peraire, J.

2016-03-01

In this paper, we introduce a Gaussian functional regression (GFR) technique that integrates multi-fidelity models with model reduction to efficiently predict the input-output relationship of a high-fidelity model. The GFR method combines the high-fidelity model with a low-fidelity model to provide an estimate of the output of the high-fidelity model in the form of a posterior distribution that can characterize uncertainty in the prediction. A reduced basis approximation is constructed upon the low-fidelity model and incorporated into the GFR method to yield an inexpensive posterior distribution of the output estimate. As this posterior distribution depends crucially on a set of training inputs at which the high-fidelity models are simulated, we develop a greedy sampling algorithm to select the training inputs. Our approach results in an output prediction model that inherits the fidelity of the high-fidelity model and has the computational complexity of the reduced basis approximation. Numerical results are presented to demonstrate the proposed approach.

Multi-Disciplinary, Multi-Fidelity Discrete Data Transfer Using Degenerate Geometry Forms

NASA Technical Reports Server (NTRS)

Olson, Erik D.

2016-01-01

In a typical multi-fidelity design process, different levels of geometric abstraction are used for different analysis methods, and transitioning from one phase of design to the next often requires a complete re-creation of the geometry. To maintain consistency between lower-order and higher-order analysis results, Vehicle Sketch Pad (OpenVSP) recently introduced the ability to generate and export several degenerate forms of the geometry, representing the type of abstraction required to perform low- to medium-order analysis for a range of aeronautical disciplines. In this research, the functionality of these degenerate models was extended, so that in addition to serving as repositories for the geometric information that is required as input to an analysis, the degenerate models can also store the results of that analysis mapped back onto the geometric nodes. At the same time, the results are also mapped indirectly onto the nodes of lower-order degenerate models using a process called aggregation, and onto higher-order models using a process called disaggregation. The mapped analysis results are available for use by any subsequent analysis in an integrated design and analysis process. A simple multi-fidelity analysis process for a single-aisle subsonic transport aircraft is used as an example case to demonstrate the value of the approach.

Development of Adaptive Model Refinement (AMoR) for Multiphysics and Multifidelity Problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turinsky, Paul

This project investigated the development and utilization of Adaptive Model Refinement (AMoR) for nuclear systems simulation applications. AMoR refers to utilization of several models of physical phenomena which differ in prediction fidelity. If the highest fidelity model is judged to always provide or exceeded the desired fidelity, than if one can determine the difference in a Quantity of Interest (QoI) between the highest fidelity model and lower fidelity models, one could utilize the fidelity model that would just provide the magnitude of the QoI desired. Assuming lower fidelity models require less computational resources, in this manner computational efficiency can bemore » realized provided the QoI value can be accurately and efficiently evaluated. This work utilized Generalized Perturbation Theory (GPT) to evaluate the QoI, by convoluting the GPT solution with the residual of the highest fidelity model determined using the solution from lower fidelity models. Specifically, a reactor core neutronics problem and thermal-hydraulics problem were studied to develop and utilize AMoR. The highest fidelity neutronics model was based upon the 3D space-time, two-group, nodal diffusion equations as solved in the NESTLE computer code. Added to the NESTLE code was the ability to determine the time-dependent GPT neutron flux. The lower fidelity neutronics model was based upon the point kinetics equations along with utilization of a prolongation operator to determine the 3D space-time, two-group flux. The highest fidelity thermal-hydraulics model was based upon the space-time equations governing fluid flow in a closed channel around a heat generating fuel rod. The Homogenous Equilibrium Mixture (HEM) model was used for the fluid and Finite Difference Method was applied to both the coolant and fuel pin energy conservation equations. The lower fidelity thermal-hydraulic model was based upon the same equations as used for the highest fidelity model but now with coarse spatial meshing, corrected somewhat by employing effective fuel heat conduction values. The effectiveness of switching between the highest fidelity model and lower fidelity model as a function of time was assessed using the neutronics problem. Based upon work completed to date, one concludes that the time switching is effective in annealing out differences between the highest and lower fidelity solutions. The effectiveness of using a lower fidelity GPT solution, along with a prolongation operator, to estimate the QoI was also assessed. The utilization of a lower fidelity GPT solution was done in an attempt to avoid the high computational burden associated with solving for the highest fidelity GPT solution. Based upon work completed to date, one concludes that the lower fidelity adjoint solution is not sufficiently accurate with regard to estimating the QoI; however, a formulation has been revealed that may provide a path for addressing this shortcoming.« less

Multi-fidelity stochastic collocation method for computation of statistical moments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xueyu, E-mail: xueyu-zhu@uiowa.edu; Linebarger, Erin M., E-mail: aerinline@sci.utah.edu; Xiu, Dongbin, E-mail: xiu.16@osu.edu

We present an efficient numerical algorithm to approximate the statistical moments of stochastic problems, in the presence of models with different fidelities. The method extends the multi-fidelity approximation method developed in . By combining the efficiency of low-fidelity models and the accuracy of high-fidelity models, our method exhibits fast convergence with a limited number of high-fidelity simulations. We establish an error bound of the method and present several numerical examples to demonstrate the efficiency and applicability of the multi-fidelity algorithm.

Zero-Fidelity Simulation: Engaging Team Coordination without Physical, Functional, or Psychological Re-Creation

NASA Technical Reports Server (NTRS)

Toups, Zachary O.; Hamilton, William A.; Kerne, Andruid

2012-01-01

Team coordination is essential across domains, enabling efficiency and safety. As technology improves, our temptation is to simulate with ever-higher fidelity, by making simulators re-create reality through their physical interfaces, functionality, and by making participants believe they are undertaking the simulated task. However, high-fidelity simulations often miss salient human-human work practices. We introduce the concept of zero-fidelity simulation (ZFS), a move away from literal high-fidelity mimesis of the concrete environment. ZFS alternatively models cooperation and communication as the basis of simulation. The ZFS Team Coordination Game (TeC) is developed from observation of fire emergency response work practice. We identify ways in which team members are mutually dependent on one another for information, and use these as the basis for the ZFS game design. The design creates a need for cooperation by restricting individual activity and requiring communication. The present research analyzes the design of interdependence in the validated ZFS TeC game. We successfully simulate interdependence between roles in emergency response without simulating the concrete environment.

The effect of bench model fidelity on fluoroscopy-guided transforaminal epidural injection training: a randomized control study.

PubMed

Gonzalez-Cota, Alan; Chiravuri, Srinivas; Stansfield, R Brent; Brummett, Chad M; Hamstra, Stanley J

2013-01-01

The purpose of this study was to determine whether high-fidelity simulators provide greater benefit than low-fidelity models in training fluoroscopy-guided transforaminal epidural injection. This educational study was a single-center, prospective, randomized 3-arm pretest-posttest design with a control arm. Eighteen anesthesia and physical medicine and rehabilitation residents were instructed how to perform a fluoroscopy-guided transforaminal epidural injection and assessed by experts on a reusable injectable phantom cadaver. The high- and low-fidelity groups received 30 minutes of supervised hands-on practice according to group assignment, and the control group received 30 minutes of didactic instruction from an expert. We found no differences at posttest between the high- and low-fidelity groups on global ratings of performance (P = 0.17) or checklist scores (P = 0.81). Participants who received either form of hands-on training significantly outperformed the control group on both the global rating of performance (control vs low-fidelity, P = 0.0048; control vs high-fidelity, P = 0.0047) and the checklist (control vs low-fidelity, P = 0.0047; control vs high-fidelity, P = 0.0047). Training an epidural procedure using a low-fidelity model may be equally effective as training on a high-fidelity model. These results are consistent with previous research on a variety of interventional procedures and further demonstrate the potential impact of simple, low-fidelity training models.

Implementation fidelity trajectories of a health promotion program in multidisciplinary settings: managing tensions in rehabilitation care.

PubMed

Hoekstra, Femke; van Offenbeek, Marjolein A G; Dekker, Rienk; Hettinga, Florentina J; Hoekstra, Trynke; van der Woude, Lucas H V; van der Schans, Cees P

2017-12-01

Although the importance of evaluating implementation fidelity is acknowledged, little is known about heterogeneity in fidelity over time. This study aims to generate insight into the heterogeneity in implementation fidelity trajectories of a health promotion program in multidisciplinary settings and the relationship with changes in patients' health behavior. This study used longitudinal data from the nationwide implementation of an evidence-informed physical activity promotion program in Dutch rehabilitation care. Fidelity scores were calculated based on annual surveys filled in by involved professionals (n = ± 70). Higher fidelity scores indicate a more complete implementation of the program's core components. A hierarchical cluster analysis was conducted on the implementation fidelity scores of 17 organizations at three different time points. Quantitative and qualitative data were used to explore organizational and professional differences between identified trajectories. Regression analyses were conducted to determine differences in patient outcomes. Three trajectories were identified as the following: 'stable high fidelity' (n = 9), 'moderate and improving fidelity' (n = 6), and 'unstable fidelity' (n = 2). The stable high fidelity organizations were generally smaller, started earlier, and implemented the program in a more structured way compared to moderate and improving fidelity organizations. At the implementation period's start and end, support from physicians and physiotherapists, professionals' appreciation, and program compatibility were rated more positively by professionals working in stable high fidelity organizations as compared to the moderate and improving fidelity organizations (p < .05). Qualitative data showed that the stable high fidelity organizations had often an explicit vision and strategy about the implementation of the program. Intriguingly, the trajectories were not associated with patients' self-reported physical activity outcomes (adjusted model β = - 651.6, t(613) = - 1032, p = .303). Differences in organizational-level implementation fidelity trajectories did not result in outcome differences at patient-level. This suggests that an effective implementation fidelity trajectory is contingent on the local organization's conditions. More specifically, achieving stable high implementation fidelity required the management of tensions: realizing a localized change vision, while safeguarding the program's standardized core components and engaging the scarce physicians throughout the process. When scaling up evidence-informed health promotion programs, we propose to tailor the management of implementation tensions to local organizations' starting position, size, and circumstances. The Netherlands National Trial Register NTR3961 . Registered 18 April 2013.

High fidelity, low cost moulage as a valid simulation tool to improve burns education.

PubMed

Pywell, M J; Evgeniou, E; Highway, K; Pitt, E; Estela, C M

2016-06-01

Simulation allows the opportunity for repeated practice in controlled, safe conditions. Moulage uses materials such as makeup to simulate clinical presentations. Moulage fidelity can be assessed by face validity (realism) and content validity (appropriateness). The aim of this project is to compare the fidelity of professional moulage to non-professional moulage in the context of a burns management course. Four actors were randomly assigned to a professional make-up artist or a course faculty member for moulage preparation such that two actors were in each group. Participants completed the actor-based burn management scenarios and answered a ten-question Likert-scale questionnaire on face and content validity. Mean scores and a linear mixed effects model were used to compare professional and non-professional moulage. Cronbach's alpha assessed internal consistency. Twenty participants experienced three out of four scenarios and at the end of the course completed a total of 60 questionnaires. Professional moulage had higher average ratings for face (4.30 v 3.80; p=0.11) and content (4.30 v 4.00; p=0.06) validity. Internal consistency of face (α=0.91) and content (α=0.85) validity questions was very good. The fidelity of professionally prepared moulage, as assessed by content validity, was higher than non-professionally prepared moulage. We have shown that using professional techniques and low cost materials we can prepare quality high fidelity moulage simulations. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Impact and Crashworthiness Characteristics of Venera Type Landers for Future Venus Missions

NASA Technical Reports Server (NTRS)

Schroeder, Kevin; Bayandor, Javid; Samareh, Jamshid

2016-01-01

In this paper an in-depth investigation of the structural design of the Venera 9-14 landers is explored. A complete reverse engineering of the Venera lander was required. The lander was broken down into its fundamental components and analyzed. This provided in-sights into the hidden features of the design. A trade study was performed to find the sensitivity of the lander's overall mass to the variation of several key parameters. For the lander's legs, the location, length, configuration, and number are all parameterized. The size of the impact ring, the radius of the drag plate, and other design features are also parameterized, and all of these features were correlated to the change of mass of the lander. A multi-fidelity design tool used for further investigation of the parameterized lander was developed. As a design was passed down from one level to the next, the fidelity, complexity, accuracy, and run time of the model increased. The low-fidelity model was a highly nonlinear analytical model developed to rapidly predict the mass of each design. The medium and high fidelity models utilized an explicit finite element framework to investigate the performance of various landers upon impact with the surface under a range of landing conditions. This methodology allowed for a large variety of designs to be investigated by the analytical model, which identified designs with the optimum structural mass to payload ratio. As promising designs emerged, investigations in the following higher fidelity models were focused on establishing their reliability and crashworthiness. The developed design tool efficiently modelled and tested the best concepts for any scenario based on critical Venusian mission requirements and constraints. Through this program, the strengths and weaknesses inherent in the Venera-Type landers were thoroughly investigated. Key features identified for the design of robust landers will be used as foundations for the development of the next generation of landers for future exploration missions to Venus.

Promoting Teachers' Implementation of Classroom-Based Prevention Programming Through Coaching: The Mediating Role of the Coach-Teacher Relationship.

PubMed

Johnson, Stacy R; Pas, Elise T; Bradshaw, Catherine P; Ialongo, Nicholas S

2018-05-01

There is growing awareness of the importance of implementation fidelity and the supports, such as coaching, to optimize it. This study examined how coaching activities (i.e., check-ins, needs assessment, modeling, and technical assistance) related directly and indirectly to implementation dosage and quality of the PAX Good Behavior Game, via a mediating pathway through working relationship. Mediation analyses of 138 teachers revealed direct effects of modeling and working relationship on implementation dosage, whereas needs assessment was associated with greater dosage indirectly, by higher ratings of the working relationship. Understanding how coaching activities promote implementation fidelity elements has implications for improving program effectiveness.

A unified, multifidelity quasi-newton optimization method with application to aero-structural designa

NASA Astrophysics Data System (ADS)

Bryson, Dean Edward

A model's level of fidelity may be defined as its accuracy in faithfully reproducing a quantity or behavior of interest of a real system. Increasing the fidelity of a model often goes hand in hand with increasing its cost in terms of time, money, or computing resources. The traditional aircraft design process relies upon low-fidelity models for expedience and resource savings. However, the reduced accuracy and reliability of low-fidelity tools often lead to the discovery of design defects or inadequacies late in the design process. These deficiencies result either in costly changes or the acceptance of a configuration that does not meet expectations. The unknown opportunity cost is the discovery of superior vehicles that leverage phenomena unknown to the designer and not illuminated by low-fidelity tools. Multifidelity methods attempt to blend the increased accuracy and reliability of high-fidelity models with the reduced cost of low-fidelity models. In building surrogate models, where mathematical expressions are used to cheaply approximate the behavior of costly data, low-fidelity models may be sampled extensively to resolve the underlying trend, while high-fidelity data are reserved to correct inaccuracies at key locations. Similarly, in design optimization a low-fidelity model may be queried many times in the search for new, better designs, with a high-fidelity model being exercised only once per iteration to evaluate the candidate design. In this dissertation, a new multifidelity, gradient-based optimization algorithm is proposed. It differs from the standard trust region approach in several ways, stemming from the new method maintaining an approximation of the inverse Hessian, that is the underlying curvature of the design problem. Whereas the typical trust region approach performs a full sub-optimization using the low-fidelity model at every iteration, the new technique finds a suitable descent direction and focuses the search along it, reducing the number of low-fidelity evaluations required. This narrowing of the search domain also alleviates the burden on the surrogate model corrections between the low- and high-fidelity data. Rather than requiring the surrogate to be accurate in a hyper-volume bounded by the trust region, the model needs only to be accurate along the forward-looking search direction. Maintaining the approximate inverse Hessian also allows the multifidelity algorithm to revert to high-fidelity optimization at any time. In contrast, the standard approach has no memory of the previously-computed high-fidelity data. The primary disadvantage of the proposed algorithm is that it may require modifications to the optimization software, whereas standard optimizers may be used as black-box drivers in the typical trust region method. A multifidelity, multidisciplinary simulation of aeroelastic vehicle performance is developed to demonstrate the optimization method. The numerical physics models include body-fitted Euler computational fluid dynamics; linear, panel aerodynamics; linear, finite-element computational structural mechanics; and reduced, modal structural bases. A central element of the multifidelity, multidisciplinary framework is a shared parametric, attributed geometric representation that ensures the analysis inputs are consistent between disciplines and fidelities. The attributed geometry also enables the transfer of data between disciplines. The new optimization algorithm, a standard trust region approach, and a single-fidelity quasi-Newton method are compared for a series of analytic test functions, using both polynomial chaos expansions and kriging to correct discrepancies between fidelity levels of data. In the aggregate, the new method requires fewer high-fidelity evaluations than the trust region approach in 51% of cases, and the same number of evaluations in 18%. The new approach also requires fewer low-fidelity evaluations, by up to an order of magnitude, in almost all cases. The efficacy of both multifidelity methods compared to single-fidelity optimization depends significantly on the behavior of the high-fidelity model and the quality of the low-fidelity approximation, though savings are realized in a large number of cases. The multifidelity algorithm is also compared to the single-fidelity quasi-Newton method for complex aeroelastic simulations. The vehicle design problem includes variables for planform shape, structural sizing, and cruise condition with constraints on trim and structural stresses. Considering the objective function reduction versus computational expenditure, the multifidelity process performs better in three of four cases in early iterations. However, the enforcement of a contracting trust region slows the multifidelity progress. Even so, leveraging the approximate inverse Hessian, the optimization can be seamlessly continued using high-fidelity data alone. Ultimately, the proposed new algorithm produced better designs in all four cases. Investigating the return on investment in terms of design improvement per computational hour confirms that the multifidelity advantage is greatest in early iterations, and managing the transition to high-fidelity optimization is critical.

Strengthening organizations to implement evidence-based clinical practices.

PubMed

VanDeusen Lukas, Carol; Engle, Ryann L; Holmes, Sally K; Parker, Victoria A; Petzel, Robert A; Nealon Seibert, Marjorie; Shwartz, Michael; Sullivan, Jennifer L

2010-01-01

Despite recognition that implementation of evidence-based clinical practices (EBPs) usually depends on the structure and processes of the larger health care organizational context, the dynamics of implementation are not well understood. This project's aim was to deepen that understanding by implementing and evaluating an organizational model hypothesized to strengthen the ability of health care organizations to facilitate EBPs. CONCEPTUAL MODEL: The model posits that implementation of EBPs will be enhanced through the presence of three interacting components: active leadership commitment to quality, robust clinical process redesign incorporating EBPs into routine operations, and use of management structures and processes to support and align redesign. In a mixed-methods longitudinal comparative case study design, seven medical centers in one network in the Department of Veterans Affairs participated in an intervention to implement the organizational model over 3 years. The network was selected randomly from three interested in using the model. The target EBP was hand-hygiene compliance. Measures included ratings of implementation fidelity, observed hand-hygiene compliance, and factors affecting model implementation drawn from interviews. Analyses support the hypothesis that greater fidelity to the organizational model was associated with higher compliance with hand-hygiene guidelines. High-fidelity sites showed larger effect sizes for improvement in hand-hygiene compliance than lower-fidelity sites. Adherence to the organizational model was in turn affected by factors in three categories: urgency to improve, organizational environment, and improvement climate. Implementation of EBPs, particularly those that cut across multiple processes of care, is a complex process with many possibilities for failure. The results provide the basis for a refined understanding of relationships among components of the organizational model and factors in the organizational context affecting them. This understanding suggests practical lessons for future implementation efforts and contributes to theoretical understanding of the dynamics of the implementation of EBPs.

Examining the association between implementation and outcomes : state-wide scale-up of school-wide positive behavior intervention and supports.

PubMed

Pas, Elise T; Bradshaw, Catherine P

2012-10-01

Although there is an established literature supporting the efficacy of a variety of prevention programs, there has been less empirical work on the translation of such research to everyday practice or when scaled-up state-wide. There is a considerable need for more research on factors that enhance implementation of programs and optimize outcomes, particularly in school settings. The current paper examines how the implementation fidelity of an increasingly popular and widely disseminated prevention model called, School-wide Positive Behavioral Interventions and Supports (SW-PBIS), relates to student outcomes within the context of a state-wide scale-up effort. Data come from a scale-up effort of SW-PBIS in Maryland; the sample included 421 elementary and middle schools trained in SW-PBIS. SW-PBIS fidelity, as measured by one of three fidelity measures, was found to be associated with higher math achievement, higher reading achievement, and lower truancy. School contextual factors were related to implementation levels and outcomes. Implications for scale-up efforts of behavioral and mental health interventions and measurement considerations are discussed.

Examining the Association Between Implementation and Outcomes

PubMed Central

Pas, Elise T.; Bradshaw, Catherine P.

2012-01-01

Although there is an established literature supporting the efficacy of a variety of prevention programs, there has been less empirical work on the tran of such research to everyday practice or when scaled-up state-wide. There is a considerable need for more research on factors that enhance implementation of programs and optimize outcomes, particularly in school settings. The current paper examines how the implementation fidelity of an increasingly popular and widely disseminated prevention model called, School-wide Positive Behavioral Interventions and Supports (SW-PBIS), relates to student outcomes within the context of a state-wide scale-up effort. Data come from a scale-up effort of SW-PBIS in Maryland; the sample included 421 elementary and middle schools trained in SW-PBIS. SW-PBIS fidelity, as measured by one of three fidelity measures, was found to be associated with higher math achievement, higher reading achievement, and lower truancy. School contextual factors were related to implementation levels and outcomes. Implications for scale-up efforts of behavioral and mental health interventions and measurement considerations are discussed. PMID:22836758

`Inverse Crime' and Model Integrity in Lightcurve Inversion applied to unresolved Space Object Identification

NASA Astrophysics Data System (ADS)

Henderson, Laura S.; Subbarao, Kamesh

2017-12-01

This work presents a case wherein the selection of models when producing synthetic light curves affects the estimation of the size of unresolved space objects. Through this case, "inverse crime" (using the same model for the generation of synthetic data and data inversion), is illustrated. This is done by using two models to produce the synthetic light curve and later invert it. It is shown here that the choice of model indeed affects the estimation of the shape/size parameters. When a higher fidelity model (henceforth the one that results in the smallest error residuals after the crime is committed) is used to both create, and invert the light curve model the estimates of the shape/size parameters are significantly better than those obtained when a lower fidelity model (in comparison) is implemented for the estimation. It is therefore of utmost importance to consider the choice of models when producing synthetic data, which later will be inverted, as the results might be misleadingly optimistic.

Teaching elliptical excision skills to novice medical students: a randomized controlled study comparing low- and high-fidelity bench models.

PubMed

Denadai, Rafael; Oshiiwa, Marie; Saad-Hossne, Rogério

2014-03-01

The search for alternative and effective forms of training simulation is needed due to ethical and medico-legal aspects involved in training surgical skills on living patients, human cadavers and living animals. To evaluate if the bench model fidelity interferes in the acquisition of elliptical excision skills by novice medical students. Forty novice medical students were randomly assigned to 5 practice conditions with instructor-directed elliptical excision skills' training (n = 8): didactic materials (control); organic bench model (low-fidelity); ethylene-vinyl acetate bench model (low-fidelity); chicken legs' skin bench model (high-fidelity); or pig foot skin bench model (high-fidelity). Pre- and post-tests were applied. Global rating scale, effect size, and self-perceived confidence based on Likert scale were used to evaluate all elliptical excision performances. The analysis showed that after training, the students practicing on bench models had better performance based on Global rating scale (all P < 0.0000) and felt more confident to perform elliptical excision skills (all P < 0.0000) when compared to the control. There was no significant difference (all P > 0.05) between the groups that trained on bench models. The magnitude of the effect (basic cutaneous surgery skills' training) was considered large (>0.80) in all measurements. The acquisition of elliptical excision skills after instructor-directed training on low-fidelity bench models was similar to the training on high-fidelity bench models; and there was a more substantial increase in elliptical excision performances of students that trained on all simulators compared to the learning on didactic materials.

Data Association Algorithms for Tracking Satellites

DTIC Science & Technology

2013-03-27

validation of the new tools. The description provided here includes the mathematical back ground and description of the models implemented, as well as a...simulation development. This work includes the addition of higher-fidelity models in CU-TurboProp and validation of the new tools. The description...ode45(), used in Ananke, and (3) provide the necessary inputs to the bidirectional reflectance distribution function ( BRDF ) model provided by Pacific

Modal identities for multibody elastic spacecraft: An aid to selecting modes for simulation

NASA Technical Reports Server (NTRS)

Hablani, Hari B.

1989-01-01

The question: Which set of modes furnishes a higher fidelity math model of dynamics of a multibody, deformable spacecraft (hinges-free or hinges-locked vehicle modes) is answered. Two sets of general, discretized, linear equations of motion of a spacecraft with an arbitrary number of deformable appendages, each articulated directly to the core body, are obtained using the above two families of modes. By a comparison of these equations, ten sets of modal identities are constructed which involve modal momenta coefficients and frequencies associated with both classes of modes. The sums of infinite series that appear in the identities are obtained in terms of mass, and first and second moments of inertia of the appendages, core body, and vehicle by using certain basic identities concerning appendage modes. Applying the above identities to a four-body spacecraft, the hinges-locked vehicle modes are found to yield a higher fidelity model than hinges-free modes, because the latter modes have nonconverging modal coefficients; a characteristic proved and illustrated.

Flight simulator fidelity assessment in a rotorcraft lateral translation maneuver

NASA Technical Reports Server (NTRS)

Hess, R. A.; Malsbury, T.; Atencio, A., Jr.

1992-01-01

A model-based methodology for assessing flight simulator fidelity in closed-loop fashion is exercised in analyzing a rotorcraft low-altitude maneuver for which flight test and simulation results were available. The addition of a handling qualities sensitivity function to a previously developed model-based assessment criteria allows an analytical comparison of both performance and handling qualities between simulation and flight test. Model predictions regarding the existence of simulator fidelity problems are corroborated by experiment. The modeling approach is used to assess analytically the effects of modifying simulator characteristics on simulator fidelity.

Learning nursing procedures: the influence of simulator fidelity and student gender on teaching effectiveness.

PubMed

Grady, Janet L; Kehrer, Rosemary G; Trusty, Carole E; Entin, Eileen B; Entin, Elliot E; Brunye, Tad T

2008-09-01

Simulation technologies are gaining widespread acceptance across a variety of educational domains and applications. The current research examines whether basic nursing procedure training with high-fidelity versus low-fidelity mannequins results in differential skill acquisition and perceptions of simulator utility. Fifty-two first-year students were taught nasogastric tube and indwelling urinary catheter insertion in one of two ways. The first group learned nasogastric tube and urinary catheter insertion using high-fidelity and low-fidelity mannequins, respectively, and the second group learned nasogastric tube and urinary catheter insertion using low-fidelity and high-fidelity mannequins, respectively. The dependent measures included student performance on nasogastric tube and urinary catheter insertion testing, as measured by observer-based instruments, and self-report questionnaires probing student attitudes about the use of simulation in nursing education. Results demonstrated higher performance with high-fidelity than with low-fidelity mannequin training. In response to a self-report posttraining questionnaire, participants expressed a more positive attitude toward the high-fidelity mannequin, especially regarding its responsiveness and realism.

Fidelity of Simulation for Pilot Training

DTIC Science & Technology

1980-12-01

is worthwhile emphasizing at this point that the study is focused on fidelity of simulators for pilot training. It does not consider simulation for...significantly higher cost than low fidelity. Motivation for 0~is study is to obtain background information on the effect of simulator fidel- ity on ...bottom of the diagram is the recom- mended approach. In practice, however, it is often the case that emphasis is placed on work in the bottom segment of

A systematic review of evidence for education and training interventions in microsurgery.

PubMed

Ghanem, Ali M; Hachach-Haram, Nadine; Leung, Clement Chi Ming; Myers, Simon Richard

2013-07-01

Over the past decade, driven by advances in educational theory and pressures for efficiency in the clinical environment, there has been a shift in surgical education and training towards enhanced simulation training. Microsurgery is a technical skill with a steep competency learning curve on which the clinical outcome greatly depends. This paper investigates the evidence for educational and training interventions of traditional microsurgical skills courses in order to establish the best evidence practice in education and training and curriculum design. A systematic review of MEDLINE, EMBASE, and PubMed databases was performed to identify randomized control trials looking at educational and training interventions that objectively improved microsurgical skill acquisition, and these were critically appraised using the BestBETs group methodology. The databases search yielded 1,148, 1,460, and 2,277 citations respectively. These were then further limited to randomized controlled trials from which abstract reviews reduced the number to 5 relevant randomised controlled clinical trials. The best evidence supported a laboratory based low fidelity model microsurgical skills curriculum. There was strong evidence that technical skills acquired on low fidelity models transfers to improved performance on higher fidelity human cadaver models and that self directed practice leads to improved technical performance. Although there is significant paucity in the literature to support current microsurgical education and training practices, simulated training on low fidelity models in microsurgery is an effective intervention that leads to acquisition of transferable skills and improved technical performance. Further research to identify educational interventions associated with accelerated skill acquisition is required.

An Investigation of the Impact of Aerodynamic Model Fidelity on Close-In Combat Effectiveness Prediction in Piloted Simulation

NASA Technical Reports Server (NTRS)

Persing, T. Ray; Bellish, Christine A.; Brandon, Jay; Kenney, P. Sean; Carzoo, Susan; Buttrill, Catherine; Guenther, Arlene

2005-01-01

Several aircraft airframe modeling approaches are currently being used in the DoD community for acquisition, threat evaluation, training, and other purposes. To date there has been no clear empirical study of the impact of airframe simulation fidelity on piloted real-time aircraft simulation study results, or when use of a particular level of fidelity is indicated. This paper documents a series of piloted simulation studies using three different levels of airframe model fidelity. This study was conducted using the NASA Langley Differential Maneuvering Simulator. Evaluations were conducted with three pilots for scenarios requiring extensive maneuvering of the airplanes during air combat. In many cases, a low-fidelity modified point-mass model may be sufficient to evaluate the combat effectiveness of the aircraft. However, in cases where high angle-of-attack flying qualities and aerodynamic performance are a factor or when precision tracking ability of the aircraft must be represented, use of high-fidelity models is indicated.

Fidelity of the representation of value in decision-making

PubMed Central

Dowding, Ben A.

2017-01-01

The ability to make optimal decisions depends on evaluating the expected rewards associated with different potential actions. This process is critically dependent on the fidelity with which reward value information can be maintained in the nervous system. Here we directly probe the fidelity of value representation following a standard reinforcement learning task. The results demonstrate a previously-unrecognized bias in the representation of value: extreme reward values, both low and high, are stored significantly more accurately and precisely than intermediate rewards. The symmetry between low and high rewards pertained despite substantially higher frequency of exposure to high rewards, resulting from preferential exploitation of more rewarding options. The observed variation in fidelity of value representation retrospectively predicted performance on the reinforcement learning task, demonstrating that the bias in representation has an impact on decision-making. A second experiment in which one or other extreme-valued option was omitted from the learning sequence showed that representational fidelity is primarily determined by the relative position of an encoded value on the scale of rewards experienced during learning. Both variability and guessing decreased with the reduction in the number of options, consistent with allocation of a limited representational resource. These findings have implications for existing models of reward-based learning, which typically assume defectless representation of reward value. PMID:28248958

Optimal control of universal quantum gates in a double quantum dot

NASA Astrophysics Data System (ADS)

Castelano, Leonardo K.; de Lima, Emanuel F.; Madureira, Justino R.; Degani, Marcos H.; Maialle, Marcelo Z.

2018-06-01

We theoretically investigate electron spin operations driven by applied electric fields in a semiconductor double quantum dot (DQD) formed in a nanowire with longitudinal potential modulated by local gating. We develop a model that describes the process of loading and unloading the DQD taking into account the overlap between the electron wave function and the leads. Such a model considers the spatial occupation and the spin Pauli blockade in a time-dependent fashion due to the highly mixed states driven by the external electric field. Moreover, we present a road map based on the quantum optimal control theory (QOCT) to find a specific electric field that performs two-qubit quantum gates on a faster timescale and with higher possible fidelity. By employing the QOCT, we demonstrate the possibility of performing within high efficiency a universal set of quantum gates {cnot, H, and T } , where cnot is the controlled-not gate, H is the Hadamard gate, and T is the π /8 gate, even in the presence of the loading/unloading process and charge noise effects. Furthermore, by varying the intensity of the applied magnetic field B , the optimized fidelity of the gates oscillates with a period inversely proportional to the gate operation time tf. This behavior can be useful to attain higher fidelity for fast gate operations (>1 GHz) by appropriately choosing B and tf to produce a maximum of the oscillation.

Unbiased multi-fidelity estimate of failure probability of a free plane jet

NASA Astrophysics Data System (ADS)

Marques, Alexandre; Kramer, Boris; Willcox, Karen; Peherstorfer, Benjamin

2017-11-01

Estimating failure probability related to fluid flows is a challenge because it requires a large number of evaluations of expensive models. We address this challenge by leveraging multiple low fidelity models of the flow dynamics to create an optimal unbiased estimator. In particular, we investigate the effects of uncertain inlet conditions in the width of a free plane jet. We classify a condition as failure when the corresponding jet width is below a small threshold, such that failure is a rare event (failure probability is smaller than 0.001). We estimate failure probability by combining the frameworks of multi-fidelity importance sampling and optimal fusion of estimators. Multi-fidelity importance sampling uses a low fidelity model to explore the parameter space and create a biasing distribution. An unbiased estimate is then computed with a relatively small number of evaluations of the high fidelity model. In the presence of multiple low fidelity models, this framework offers multiple competing estimators. Optimal fusion combines all competing estimators into a single estimator with minimal variance. We show that this combined framework can significantly reduce the cost of estimating failure probabilities, and thus can have a large impact in fluid flow applications. This work was funded by DARPA.

Teaching Elliptical Excision Skills to Novice Medical Students: A Randomized Controlled Study Comparing Low- and High-Fidelity Bench Models

PubMed Central

Denadai, Rafael; Oshiiwa, Marie; Saad-Hossne, Rogério

2014-01-01

Background: The search for alternative and effective forms of training simulation is needed due to ethical and medico-legal aspects involved in training surgical skills on living patients, human cadavers and living animals. Aims: To evaluate if the bench model fidelity interferes in the acquisition of elliptical excision skills by novice medical students. Materials and Methods: Forty novice medical students were randomly assigned to 5 practice conditions with instructor-directed elliptical excision skills’ training (n = 8): didactic materials (control); organic bench model (low-fidelity); ethylene-vinyl acetate bench model (low-fidelity); chicken legs’ skin bench model (high-fidelity); or pig foot skin bench model (high-fidelity). Pre- and post-tests were applied. Global rating scale, effect size, and self-perceived confidence based on Likert scale were used to evaluate all elliptical excision performances. Results: The analysis showed that after training, the students practicing on bench models had better performance based on Global rating scale (all P < 0.0000) and felt more confident to perform elliptical excision skills (all P < 0.0000) when compared to the control. There was no significant difference (all P > 0.05) between the groups that trained on bench models. The magnitude of the effect (basic cutaneous surgery skills’ training) was considered large (>0.80) in all measurements. Conclusion: The acquisition of elliptical excision skills after instructor-directed training on low-fidelity bench models was similar to the training on high-fidelity bench models; and there was a more substantial increase in elliptical excision performances of students that trained on all simulators compared to the learning on didactic materials. PMID:24700937

Evaluating display fidelity and interaction fidelity in a virtual reality game.

PubMed

McMahan, Ryan P; Bowman, Doug A; Zielinski, David J; Brady, Rachael B

2012-04-01

In recent years, consumers have witnessed a technological revolution that has delivered more-realistic experiences in their own homes through high-definition, stereoscopic televisions and natural, gesture-based video game consoles. Although these experiences are more realistic, offering higher levels of fidelity, it is not clear how the increased display and interaction aspects of fidelity impact the user experience. Since immersive virtual reality (VR) allows us to achieve very high levels of fidelity, we designed and conducted a study that used a six-sided CAVE to evaluate display fidelity and interaction fidelity independently, at extremely high and low levels, for a VR first-person shooter (FPS) game. Our goal was to gain a better understanding of the effects of fidelity on the user in a complex, performance-intensive context. The results of our study indicate that both display and interaction fidelity significantly affect strategy and performance, as well as subjective judgments of presence, engagement, and usability. In particular, performance results were strongly in favor of two conditions: low-display, low-interaction fidelity (representative of traditional FPS games) and high-display, high-interaction fidelity (similar to the real world).

Fidelity and breeding probability related to population density and individual quality in black brent geese Branta bernicla nigricans

USGS Publications Warehouse

Sedinger, J.S.; Chelgren, N.D.; Ward, D.H.; Lindberg, M.S.

2008-01-01

1. Patterns of temporary emigration (associated with non-breeding) are important components of variation in individual quality. Permanent emigration from the natal area has important implications for both individual fitness and local population dynamics. 2. We estimated both permanent and temporary emigration of black brent geese (Branta bernicla nigricans Lawrence) from the Tutakoke River colony, using observations of marked brent geese on breeding and wintering areas, and recoveries of ringed individuals by hunters. We used the likelihood developed by Lindberg, Kendall, Hines & Anderson 2001 (Combining band recovery data and Pollock's robust design to model temporary and permanent emigration. Biometrics, 57, 273-281) to assess hypotheses and estimate parameters. 3. Temporary emigration (the converse of breeding) varied among age classes up to age 5, and differed between individuals that bred in the previous years vs. those that did not. Consistent with the hypothesis of variation in individual quality, individuals with a higher probability of breeding in one year also had a higher probability of breeding the next year. 4. Natal fidelity of females ranged from 0.70 ?? 0.07-0.96 ?? 0.18 and averaged 0.83. In contrast to Lindberg et al. (1998), we did not detect a relationship between fidelity and local population density. Natal fidelity was negatively correlated with first-year survival, suggesting that competition among individuals of the same age for breeding territories influenced dispersal. Once females nested at the Tutakoke River, colony breeding fidelity was 1.0. 5. Our analyses show substantial variation in individual quality associated with fitness, which other analyses suggest is strongly influenced by early environment. Our analyses also suggest substantial interchange among breeding colonies of brent geese, as first shown by Lindberg et al. (1998).

Fidelity to the housing first model and effectiveness of permanent supported housing programs in California.

PubMed

Gilmer, Todd P; Stefancic, Ana; Katz, Marian L; Sklar, Marisa; Tsemberis, Sam; Palinkas, Lawrence A

2014-11-01

Permanent supported housing programs are being implemented throughout the United States. This study examined the relationship between fidelity to the Housing First model and residential outcomes among clients of full service partnerships (FSPs) in California. This study had a mixed-methods design. Quantitative administrative and survey data were used to describe FSP practices and to examine the association between fidelity to Housing First and residential outcomes in the year before and after enrollment of 6,584 FSP clients in 86 programs. Focus groups at 20 FSPs provided qualitative data to enhance the understanding of these findings with actual accounts of housing-related experiences in high- and low-fidelity programs. Prior to enrollment, the mean days of homelessness were greater at high- versus low-fidelity (101 versus 46 days) FSPs. After adjustment for individual characteristics, the analysis found that days spent homeless after enrollment declined by 87 at high-fidelity programs and by 34 at low-fidelity programs. After adjustment for days spent homeless before enrollment, days spent homeless after enrollment declined by 63 at high-fidelity programs and by 53 at low-fidelity programs. After enrollment, clients at high-fidelity programs spent more than 60 additional days in apartments than clients at low-facility programs. Differences were found between high- and low-fidelity FSPs in client choice in housing and how much clients' goals were considered in housing placement. Programs with greater fidelity to the Housing First model enrolled clients with longer histories of homelessness and placed most of them in apartments.

Optimal control of hybrid qubits: Implementing the quantum permutation algorithm

NASA Astrophysics Data System (ADS)

Rivera-Ruiz, C. M.; de Lima, E. F.; Fanchini, F. F.; Lopez-Richard, V.; Castelano, L. K.

2018-03-01

The optimal quantum control theory is employed to determine electric pulses capable of producing quantum gates with a fidelity higher than 0.9997, when noise is not taken into account. Particularly, these quantum gates were chosen to perform the permutation algorithm in hybrid qubits in double quantum dots (DQDs). The permutation algorithm is an oracle based quantum algorithm that solves the problem of the permutation parity faster than a classical algorithm without the necessity of entanglement between particles. The only requirement for achieving the speedup is the use of a one-particle quantum system with at least three levels. The high fidelity found in our results is closely related to the quantum speed limit, which is a measure of how fast a quantum state can be manipulated. Furthermore, we model charge noise by considering an average over the optimal field centered at different values of the reference detuning, which follows a Gaussian distribution. When the Gaussian spread is of the order of 5 μ eV (10% of the correct value), the fidelity is still higher than 0.95. Our scheme also can be used for the practical realization of different quantum algorithms in DQDs.

Construction of nested maximin designs based on successive local enumeration and modified novel global harmony search algorithm

NASA Astrophysics Data System (ADS)

Yi, Jin; Li, Xinyu; Xiao, Mi; Xu, Junnan; Zhang, Lin

2017-01-01

Engineering design often involves different types of simulation, which results in expensive computational costs. Variable fidelity approximation-based design optimization approaches can realize effective simulation and efficiency optimization of the design space using approximation models with different levels of fidelity and have been widely used in different fields. As the foundations of variable fidelity approximation models, the selection of sample points of variable-fidelity approximation, called nested designs, is essential. In this article a novel nested maximin Latin hypercube design is constructed based on successive local enumeration and a modified novel global harmony search algorithm. In the proposed nested designs, successive local enumeration is employed to select sample points for a low-fidelity model, whereas the modified novel global harmony search algorithm is employed to select sample points for a high-fidelity model. A comparative study with multiple criteria and an engineering application are employed to verify the efficiency of the proposed nested designs approach.

Recommendations on Model Fidelity for Wind Turbine Gearbox Simulations; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, J.; Lacava, W.; Austin, J.

2015-02-01

This work investigates the minimum level of fidelity required to accurately simulate wind turbine gearboxes using state-of-the-art design tools. Excessive model fidelity including drivetrain complexity, gearbox complexity, excitation sources, and imperfections, significantly increases computational time, but may not provide a commensurate increase in the value of the results. Essential designparameters are evaluated, including the planetary load-sharing factor, gear tooth load distribution, and sun orbit motion. Based on the sensitivity study results, recommendations for the minimum model fidelities are provided.

Limited genetic differentiation among breeding, molting, and wintering groups of the threatened Steller's eider: The role of historic and contemporary factors

USGS Publications Warehouse

Pearce, J.M.; Talbot, S.L.; Petersen, M.R.; Rearick, J.R.

2005-01-01

Due to declines in the Alaska breeding population, the Steller's eider (Polysticta stelleri) was listed as threatened in North America in 1997. Periodic non-breeding in Russia and Alaska has hampered field-based assessments of behavioral patterns critical to recovery plans, such as levels of breeding site fidelity and movements among three regional populations: Atlantic-Russia, Pacific-Russia and Alaska. Therefore, we analyzed samples from across the species range with seven nuclear microsatellite DNA loci and cytochrome b mitochondrial (mt)DNA sequence data to infer levels of interchange among sampling areas and patterns of site fidelity. Results demonstrated low levels of population differentiation within Atlantic and Pacific nesting areas, with higher levels observed between these regions, but only for mtDNA. Bayesian analysis of microsatellite data from wintering and molting birds showed no signs of sub-population structure, even though band-recovery data suggests multiple breeding areas are present. We observed higher estimates of F-statistics for female mtDNA data versus male data, suggesting female-biased natal site fidelity. Summary statistics for mtDNA were consistent with models of historic population expansion. Lack of spatial structure in Steller's eiders may result largely from insufficient time since historic population expansions for behaviors, such as natal site fidelity, to isolate breeding areas genetically. However, other behaviors such as the periodic non-breeding observed in Steller's eiders may also play a more contemporary role in genetic homogeneity, especially for microsatellite loci. 

High Fidelity System Simulation of Multiple Components in Support of the UEET Program

NASA Technical Reports Server (NTRS)

Plybon, Ronald C.; VanDeWall, Allan; Sampath, Rajiv; Balasubramaniam, Mahadevan; Mallina, Ramakrishna; Irani, Rohinton

2006-01-01

The High Fidelity System Simulation effort has addressed various important objectives to enable additional capability within the NPSS framework. The scope emphasized High Pressure Turbine and High Pressure Compressor components. Initial effort was directed at developing and validating intermediate fidelity NPSS model using PD geometry and extended to high-fidelity NPSS model by overlaying detailed geometry to validate CFD against rig data. Both "feedforward" and feedback" approaches of analysis zooming was employed to enable system simulation capability in NPSS. These approaches have certain benefits and applicability in terms of specific applications "feedback" zooming allows the flow-up of information from high-fidelity analysis to be used to update the NPSS model results by forcing the NPSS solver to converge to high-fidelity analysis predictions. This apporach is effective in improving the accuracy of the NPSS model; however, it can only be used in circumstances where there is a clear physics-based strategy to flow up the high-fidelity analysis results to update the NPSS system model. "Feed-forward" zooming approach is more broadly useful in terms of enabling detailed analysis at early stages of design for a specified set of critical operating points and using these analysis results to drive design decisions early in the development process.

Replication fidelity improvement of PMMA microlens array based on weight evaluation and optimization

NASA Astrophysics Data System (ADS)

Jiang, Bing-yan; Shen, Long-jiang; Peng, Hua-jiang; Yin, Xiang-lin

2007-12-01

High replication fidelity is a prerequisite of high quality plastic microlens array in injection molding. But, there's not an economical and practical method to evaluate and improve the replication fidelity until now. Based on part weight evaluation and optimization, this paper presents a new method of replication fidelity improvement. Firstly, a simplified analysis model of PMMA micro columns arrays (5×16) with 200μm diameter was set up. And then, Flow (3D) module of Moldflow MPI6.0 based on Navier-Stokes equations was used to calculate the weight of the micro columns arrays in injection molding. The effects of processing parameters (melt temperature, mold temperature, injection time, packing pressure and packing time) on the part weight were investigated in the simulations. The simulation results showed that the mold temperature and the injection time have important effects on the filling of micro columns; the optimal mold temperature and injection time for better replication fidelity could be determined by the curves of mold temperature vs part weight and injection time vs part weight. At last, the effects of processing parameters on part weight of micro columns array were studied experimentally. The experimental results showed that the increase of melt temperature and mold temperature can make the packing pressure transfer to micro cavity more effectively through runner system, and increase the part weight. From the observation results of the image measuring apparatus, it was discovered that the higher the part weight, the better the filling of the microstructures. In conclusion, part weight can be used to evaluate the replication fidelity of micro-feature structured parts primarily; which is an economical and practical method to improve the replication fidelity of microlens arrays based on weight evaluation and optimization.

Numerical study of phase conjugation in stimulated Brillouin scattering from an optical waveguide

NASA Astrophysics Data System (ADS)

Lehmberg, R. H.

1983-05-01

Stimulated Brillouin scattering (SBS) in a multimode optical waveguide is examined, and the parameters that affect the wavefront conjugation fidelity are studied. The nonlinear propagation code is briefly described and the calculated quantities are defined. The parameter study in the low reflectivity limit is described, and the effects of pump depletion are considered. The waveguide produced significantly higher fidelities than the focused configuration, in agreement with several experimental studies. The light scattered back through the phase aberrator exhibited a farfield intenstiy profile closely matching that of the incident beam; however, the nearfield intensity exhibited large and rapid spatial inhomogeneities across the entire aberrator, even for conjugation fidelities as high as 98 percent. In the absence of pump depletion, the fidelity increased with average pump intensity for amplitude gains up to around e to the 10th and then decreased slowly and monotonically with higher intensity. For all cases, pump depletion significantly enhanced the fidelity of the wavefront conjugation by inhibiting the small-scale pulling effect.

First-Order Frameworks for Managing Models in Engineering Optimization

NASA Technical Reports Server (NTRS)

Alexandrov, Natlia M.; Lewis, Robert Michael

2000-01-01

Approximation/model management optimization (AMMO) is a rigorous methodology for attaining solutions of high-fidelity optimization problems with minimal expense in high- fidelity function and derivative evaluation. First-order AMMO frameworks allow for a wide variety of models and underlying optimization algorithms. Recent demonstrations with aerodynamic optimization achieved three-fold savings in terms of high- fidelity function and derivative evaluation in the case of variable-resolution models and five-fold savings in the case of variable-fidelity physics models. The savings are problem dependent but certain trends are beginning to emerge. We give an overview of the first-order frameworks, current computational results, and an idea of the scope of the first-order framework applicability.

How to teach emergency procedural skills in an outdoor environment using low-fidelity simulation.

PubMed

Saxon, Kathleen D; Kapadia, Alison P R; Juneja, Nadia S; Bassin, Benjamin S

2014-03-01

Teaching emergency procedural skills in a wilderness setting can be logistically challenging. To teach these skills as part of a wilderness medicine elective for medical students, we designed an outdoor simulation session with low-fidelity models. The session involved 6 stations in which procedural skills were taught using homemade low-fidelity simulators. At each station, the students encountered a "victim," who required an emergency procedure that was performed using the low-fidelity model. The models are easy and inexpensive to construct, and their design and implementation in the session is described here. Using low-fidelity simulation models in an outdoor setting is an effective teaching tool for emergency wilderness medicine procedures and can easily be reproduced in future wilderness medicine courses. © 2014 Wilderness Medical Society Published by Wilderness Medical Society All rights reserved.

Approaches and possible improvements in the area of multibody dynamics modeling

NASA Technical Reports Server (NTRS)

Lips, K. W.; Singh, R.

1987-01-01

A wide ranging look is taken at issues involved in the dynamic modeling of complex, multibodied orbiting space systems. Capabilities and limitations of two major codes (DISCOS, TREETOPS) are assessed and possible extensions to the CONTOPS software are outlined. In addition, recommendations are made concerning the direction future development should take in order to achieve higher fidelity, more computationally efficient multibody software solutions.

Numerical exploration of dissimilar supersonic coaxial jets mixing

NASA Astrophysics Data System (ADS)

Dharavath, Malsur; Manna, P.; Chakraborty, Debasis

2015-06-01

Mixing of two coaxial supersonic dissimilar gases in free jet environment is numerically explored. Three dimensional RANS equations with a k-ε turbulence model are solved using commercial CFD software. Two important experimental cases (RELIEF experiments) representing compressible mixing flow phenomenon under scramjet operating conditions for which detail profiles of thermochemical variables are available are taken as validation cases. Two different convective Mach numbers 0.16 and 0.70 are considered for simulations. The computed growth rate, pitot pressure and mass fraction profiles for both these cases match extremely well with experimental values and results of other high fidelity numerical results both in far field and near field regions. For higher convective Mach number predicted growth rate matches nicely with empirical Dimotakis curve; whereas for lower convective Mach number, predicted growth rate is higher. It is shown that well resolved RANS calculation can capture the mixing of two supersonic dissimilar gases better than high fidelity LES calculations.

State resolved vibrational relaxation modeling for strongly nonequilibrium flows

NASA Astrophysics Data System (ADS)

Boyd, Iain D.; Josyula, Eswar

2011-05-01

Vibrational relaxation is an important physical process in hypersonic flows. Activation of the vibrational mode affects the fundamental thermodynamic properties and finite rate relaxation can reduce the degree of dissociation of a gas. Low fidelity models of vibrational activation employ a relaxation time to capture the process at a macroscopic level. High fidelity, state-resolved models have been developed for use in continuum gas dynamics simulations based on computational fluid dynamics (CFD). By comparison, such models are not as common for use with the direct simulation Monte Carlo (DSMC) method. In this study, a high fidelity, state-resolved vibrational relaxation model is developed for the DSMC technique. The model is based on the forced harmonic oscillator approach in which multi-quantum transitions may become dominant at high temperature. Results obtained for integrated rate coefficients from the DSMC model are consistent with the corresponding CFD model. Comparison of relaxation results obtained with the high-fidelity DSMC model shows significantly less excitation of upper vibrational levels in comparison to the standard, lower fidelity DSMC vibrational relaxation model. Application of the new DSMC model to a Mach 7 normal shock wave in carbon monoxide provides better agreement with experimental measurements than the standard DSMC relaxation model.

Nurses' fidelity to theory-based core components when implementing Family Health Conversations - a qualitative inquiry.

PubMed

Östlund, Ulrika; Bäckström, Britt; Lindh, Viveca; Sundin, Karin; Saveman, Britt-Inger

2015-09-01

A family systems nursing intervention, Family Health Conversation, has been developed in Sweden by adapting the Calgary Family Assessment and Intervention Models and the Illness Beliefs Model. The intervention has several theoretical assumptions, and one way translate the theory into practice is to identify core components. This may produce higher levels of fidelity to the intervention. Besides information about how to implement an intervention in accordance to how it was developed, evaluating whether it was actually implemented as intended is important. Accordingly, we describe the nurses' fidelity to the identified core components of Family Health Conversation. Six nurses, working in alternating pairs, conducted Family Health Conversations with seven families in which a family member younger than 65 had suffered a stroke. The intervention contained a series of three-1-hour conversations held at 2-3 week intervals. The nurses followed a conversation structure based on 12 core components identified from theoretical assumptions. The transcripts of the 21 conversations were analysed using manifest qualitative content analysis with a deductive approach. The 'core components' seemed to be useful even if nurses' fidelity varied among the core components. Some components were followed relatively well, but others were not. This indicates that the process for achieving fidelity to the intervention can be improved, and that it is necessary for nurses to continually learn theory and to practise family systems nursing. We suggest this can be accomplished through reflections, role play and training on the core components. Furthermore, as in this study, joint reflections on how the core components have been implemented can lead to deeper understanding and knowledge of how Family Health Conversation can be delivered as intended. © 2014 Nordic College of Caring Science.

Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

PubMed

Massey, Steven M; Spring, Justin B; Russell, Timothy H

2008-07-21

Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

Efficient critical design load case identification for floating offshore wind turbines with a reduced nonlinear model

NASA Astrophysics Data System (ADS)

Matha, Denis; Sandner, Frank; Schlipf, David

2014-12-01

Design verification of wind turbines is performed by simulation of design load cases (DLC) defined in the IEC 61400-1 and -3 standards or equivalent guidelines. Due to the resulting large number of necessary load simulations, here a method is presented to reduce the computational effort for DLC simulations significantly by introducing a reduced nonlinear model and simplified hydro- and aerodynamics. The advantage of the formulation is that the nonlinear ODE system only contains basic mathematic operations and no iterations or internal loops which makes it very computationally efficient. Global turbine extreme and fatigue loads such as rotor thrust, tower base bending moment and mooring line tension, as well as platform motions are outputs of the model. They can be used to identify critical and less critical load situations to be then analysed with a higher fidelity tool and so speed up the design process. Results from these reduced model DLC simulations are presented and compared to higher fidelity models. Results in frequency and time domain as well as extreme and fatigue load predictions demonstrate that good agreement between the reduced and advanced model is achieved, allowing to efficiently exclude less critical DLC simulations, and to identify the most critical subset of cases for a given design. Additionally, the model is applicable for brute force optimization of floater control system parameters.

NDARC-NASA Design and Analysis of Rotorcraft Theoretical Basis and Architecture

NASA Technical Reports Server (NTRS)

Johnson, Wayne

2010-01-01

The theoretical basis and architecture of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are described. The principal tasks of NDARC are to design (or size) a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated. The aircraft attributes are obtained from the sum of the component attributes. NDARC provides a capability to model general rotorcraft configurations, and estimate the performance and attributes of advanced rotor concepts. The software has been implemented with low-fidelity models, typical of the conceptual design environment. Incorporation of higher-fidelity models will be possible, as the architecture of the code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis and optimization.

Scaling up the evaluation of psychotherapy: evaluating motivational interviewing fidelity via statistical text classification

PubMed Central

2014-01-01

Background Behavioral interventions such as psychotherapy are leading, evidence-based practices for a variety of problems (e.g., substance abuse), but the evaluation of provider fidelity to behavioral interventions is limited by the need for human judgment. The current study evaluated the accuracy of statistical text classification in replicating human-based judgments of provider fidelity in one specific psychotherapy—motivational interviewing (MI). Method Participants (n = 148) came from five previously conducted randomized trials and were either primary care patients at a safety-net hospital or university students. To be eligible for the original studies, participants met criteria for either problematic drug or alcohol use. All participants received a type of brief motivational interview, an evidence-based intervention for alcohol and substance use disorders. The Motivational Interviewing Skills Code is a standard measure of MI provider fidelity based on human ratings that was used to evaluate all therapy sessions. A text classification approach called a labeled topic model was used to learn associations between human-based fidelity ratings and MI session transcripts. It was then used to generate codes for new sessions. The primary comparison was the accuracy of model-based codes with human-based codes. Results Receiver operating characteristic (ROC) analyses of model-based codes showed reasonably strong sensitivity and specificity with those from human raters (range of area under ROC curve (AUC) scores: 0.62 – 0.81; average AUC: 0.72). Agreement with human raters was evaluated based on talk turns as well as code tallies for an entire session. Generated codes had higher reliability with human codes for session tallies and also varied strongly by individual code. Conclusion To scale up the evaluation of behavioral interventions, technological solutions will be required. The current study demonstrated preliminary, encouraging findings regarding the utility of statistical text classification in bridging this methodological gap. PMID:24758152

Value centric approaches to the design, operations and maintenance of wind turbines

NASA Astrophysics Data System (ADS)

Khadabadi, Madhur Aravind

Wind turbine maintenance is emerging as an unexpectedly high component of turbine operating cost, and there is an increasing interest in managing this cost. This thesis presents an alternative view of maintenance as a value-driver, and develops an optimization algorithm to evaluate the value delivered by different maintenance techniques. I view maintenance as an operation that moves the turbine to an improved state in which it can generate more power and, thus, earn more revenue. To implement this approach, I model the stochastic deterioration of the turbine in two dimensions: the deterioration rate, and the extent of deterioration, and then use maintenance to improve the state of the turbine. The value of the turbine is the difference between the revenue from to the power generation and the costs incurred in operation and maintenance. With a focus on blade deterioration, I evaluate the value delivered by implementing two different maintenance schemes, predictive maintenance and scheduled maintenance. An example of predictive maintenance technique is the use of Condition Monitoring Systems to precisely detect deterioration. I model Condition Monitoring System (CMS) of different degrees of fidelity, where a higher fidelity CMS would allow the blade state to be determined with a higher precision. The same model is then applied for the scheduled maintenance technique. The improved state information obtained from these techniques is then used to derive an optimal maintenance strategy. The difference between the value of the turbine with and without the inspection type can be interpreted as the value of the inspection. The results indicate that a higher fidelity (and more expensive) inspection method does not necessarily yield the highest value, and, that there is an optimal level of fidelity that results in maximum value. The results also aim to inform the operator of the impact of regional parameters such as wind speed, variance and maintenance costs to the optimal maintenance strategy. The contributions of this work are twofold. First, I present a practical approach to wind turbine valuation that takes operating and market conditions into account. This work should therefore be useful to wind farm operators, investors and decision makers. Second, I show how the value of a maintenance scheme can be explicitly assessed for different conditions.

Evaluation of the CORDEX-Africa multi-RCM hindcast: systematic model errors

NASA Astrophysics Data System (ADS)

Kim, J.; Waliser, Duane E.; Mattmann, Chris A.; Goodale, Cameron E.; Hart, Andrew F.; Zimdars, Paul A.; Crichton, Daniel J.; Jones, Colin; Nikulin, Grigory; Hewitson, Bruce; Jack, Chris; Lennard, Christopher; Favre, Alice

2014-03-01

Monthly-mean precipitation, mean (TAVG), maximum (TMAX) and minimum (TMIN) surface air temperatures, and cloudiness from the CORDEX-Africa regional climate model (RCM) hindcast experiment are evaluated for model skill and systematic biases. All RCMs simulate basic climatological features of these variables reasonably, but systematic biases also occur across these models. All RCMs show higher fidelity in simulating precipitation for the west part of Africa than for the east part, and for the tropics than for northern Sahara. Interannual variation in the wet season rainfall is better simulated for the western Sahel than for the Ethiopian Highlands. RCM skill is higher for TAVG and TMAX than for TMIN, and regionally, for the subtropics than for the tropics. RCM skill in simulating cloudiness is generally lower than for precipitation or temperatures. For all variables, multi-model ensemble (ENS) generally outperforms individual models included in ENS. An overarching conclusion in this study is that some model biases vary systematically for regions, variables, and metrics, posing difficulties in defining a single representative index to measure model fidelity, especially for constructing ENS. This is an important concern in climate change impact assessment studies because most assessment models are run for specific regions/sectors with forcing data derived from model outputs. Thus, model evaluation and ENS construction must be performed separately for regions, variables, and metrics as required by specific analysis and/or assessments. Evaluations using multiple reference datasets reveal that cross-examination, quality control, and uncertainty estimates of reference data are crucial in model evaluations.

Efficient High-Fidelity, Geometrically Exact, Multiphysics Structural Models

DTIC Science & Technology

2011-10-14

fuctionally graded core. International Journal for Numerical Methods in Engineering, 68:940– 966, 2006. 7F. Shang, Z. Wang, and Z. Li. Analysis of...normal deformable plate theory and MLPG method with radial basis fuctions . Composite Structures, 80:539– 552, 2007. 17W. Zhen and W. Chen. A higher-order...functionally graded plates by using higher-order shear and normal deformable plate theory and MLPG method with radial basis fuctions . Composite Structures, 80

Enhanced fidelity of an educational intervention on skin self-examination through surveillance and standardization

PubMed Central

Gaber, Rikki; Mallett, Kimberly A.; Hultgren, Brittney; Turrisi, Rob; Gilbertsen, Margaret L.; Martini, Mary C.; Robinson, June K.

2014-01-01

Background Melanoma can metastasize but is often successfully treated when discovered in an early stage. Melanoma patients and their skin check partners can learn skin self-examination (SSE) skills and these skills can be improved by practice. The purpose of this study is to determine the degree of fidelity with which educational in-person SSE intervention can be delivered by trained research coordinators to patients at risk of developing another melanoma and their skin check partners. Methods The in-person intervention was performed in two iterations. In phase 1 (2006-2008), the research coordinators were trained to perform the intervention using a written script. In phase 2 (2011-2013), the research coordinators were trained to perform the intervention with a PowerPoint aid. Each research coordinator was individually counseled by one of the authors (KM) to insure standardization and enhance fidelity of intervention delivery. Phase 1 and Phase 2 were compared on 16 fidelity components. Further, Phase 2 fidelity was assessed by comparing mean scores of fidelity across the five research coordinators who delivered the intervention. Results Phase 2, which utilized a PowerPoint aid, was delivered with a higher degree of fidelity compared to phase 1with four fidelity components with significantly higher fidelity than Phase 1: 1) Explained details of melanoma, χ2 (1, n = 199)= 96.31, p < .001, 2) Discussed when to call doctor, χ2 (1, n = 199) = 53.68, p < .001 3) Explained assessment at month 1, χ2 (1, n = 199)= 12.39, p < .01, and 4) Explained assessment at month 2, χ2 (1, n = 199) = 117.75, p < .001. Further, no significant differences on mean fidelity were found across research coordinators in Phase 2. Discussion When using the PowerPoint aide, the research coordinators delivered the intervention with high fidelity (all scores >14) and there were no mean differences in fidelity across research coordinators, indicating consistency in fidelity. This can be attributed to the standardization and cueing that the PowerPoint program offered. Supervision was also a key component in establishing and maintaining fidelity of the patient educational process. This method of intervention delivery enables trained healthcare professionals to deliver an educational intervention in an effective, consistent manner. PMID:25414761

Enhanced fidelity of an educational intervention on skin self-examination through surveillance and standardization.

PubMed

Gaber, Rikki; Mallett, Kimberly A; Hultgren, Brittney; Turrisi, Rob; Gilbertsen, Margaret L; Martini, Mary C; Robinson, June K

2014-01-01

Melanoma can metastasize but is often successfully treated when discovered in an early stage. Melanoma patients and their skin check partners can learn skin self-examination (SSE) skills and these skills can be improved by practice. The purpose of this study is to determine the degree of fidelity with which educational in-person SSE intervention can be delivered by trained research coordinators to patients at risk of developing another melanoma and their skin check partners. The in-person intervention was performed in two iterations. In phase 1 (2006-2008), the research coordinators were trained to perform the intervention using a written script. In phase 2 (2011-2013), the research coordinators were trained to perform the intervention with a PowerPoint aid. Each research coordinator was individually counseled by one of the authors (KM) to insure standardization and enhance fidelity of intervention delivery. Phase 1 and Phase 2 were compared on 16 fidelity components. Further, Phase 2 fidelity was assessed by comparing mean scores of fidelity across the five research coordinators who delivered the intervention. Phase 2, which utilized a PowerPoint aid, was delivered with a higher degree of fidelity compared to phase 1with four fidelity components with significantly higher fidelity than Phase 1: 1) Explained details of melanoma, χ 2 (1, n = 199)= 96.31, p < .001, 2) Discussed when to call doctor, χ 2 (1, n = 199) = 53.68, p < .001 3) Explained assessment at month 1, χ 2 (1, n = 199)= 12.39, p < .01, and 4) Explained assessment at month 2, χ 2 (1, n = 199) = 117.75, p < .001. Further, no significant differences on mean fidelity were found across research coordinators in Phase 2. When using the PowerPoint aide, the research coordinators delivered the intervention with high fidelity (all scores >14) and there were no mean differences in fidelity across research coordinators, indicating consistency in fidelity. This can be attributed to the standardization and cueing that the PowerPoint program offered. Supervision was also a key component in establishing and maintaining fidelity of the patient educational process. This method of intervention delivery enables trained healthcare professionals to deliver an educational intervention in an effective, consistent manner.

Hybrid surrogate-model-based multi-fidelity efficient global optimization applied to helicopter blade design

NASA Astrophysics Data System (ADS)

Ariyarit, Atthaphon; Sugiura, Masahiko; Tanabe, Yasutada; Kanazaki, Masahiro

2018-06-01

A multi-fidelity optimization technique by an efficient global optimization process using a hybrid surrogate model is investigated for solving real-world design problems. The model constructs the local deviation using the kriging method and the global model using a radial basis function. The expected improvement is computed to decide additional samples that can improve the model. The approach was first investigated by solving mathematical test problems. The results were compared with optimization results from an ordinary kriging method and a co-kriging method, and the proposed method produced the best solution. The proposed method was also applied to aerodynamic design optimization of helicopter blades to obtain the maximum blade efficiency. The optimal shape obtained by the proposed method achieved performance almost equivalent to that obtained using the high-fidelity, evaluation-based single-fidelity optimization. Comparing all three methods, the proposed method required the lowest total number of high-fidelity evaluation runs to obtain a converged solution.

Return rate, fidelity, and dispersal in a breeding population of flammulated owls (Otus flammeolus)

Treesearch

Brian D. Linkhart; Richard T. Reynolds

2007-01-01

We estimated annual return rate, fidelity, and breeding dispersal in a migratory population of Flammulated Owls (Otus flammeolus) in central Colorado. Return rates, based on capture-recapture histories of 39 males and 52 females from 1981 to 2003, were higher for males (84%) than for females (45%). Annual recapture probability was higher for females...

An adaptive sampling method for variable-fidelity surrogate models using improved hierarchical kriging

NASA Astrophysics Data System (ADS)

Hu, Jiexiang; Zhou, Qi; Jiang, Ping; Shao, Xinyu; Xie, Tingli

2018-01-01

Variable-fidelity (VF) modelling methods have been widely used in complex engineering system design to mitigate the computational burden. Building a VF model generally includes two parts: design of experiments and metamodel construction. In this article, an adaptive sampling method based on improved hierarchical kriging (ASM-IHK) is proposed to refine the improved VF model. First, an improved hierarchical kriging model is developed as the metamodel, in which the low-fidelity model is varied through a polynomial response surface function to capture the characteristics of a high-fidelity model. Secondly, to reduce local approximation errors, an active learning strategy based on a sequential sampling method is introduced to make full use of the already required information on the current sampling points and to guide the sampling process of the high-fidelity model. Finally, two numerical examples and the modelling of the aerodynamic coefficient for an aircraft are provided to demonstrate the approximation capability of the proposed approach, as well as three other metamodelling methods and two sequential sampling methods. The results show that ASM-IHK provides a more accurate metamodel at the same simulation cost, which is very important in metamodel-based engineering design problems.

Parametrics on 2D Navier-Stokes analysis of a Mach 2.68 bifurcated rectangular mixed-compression inlet

NASA Technical Reports Server (NTRS)

Mizukami, M.; Saunders, J. D.

1995-01-01

The supersonic diffuser of a Mach 2.68 bifurcated, rectangular, mixed-compression inlet was analyzed using a two-dimensional (2D) Navier-Stokes flow solver. Parametric studies were performed on turbulence models, computational grids and bleed models. The computer flowfield was substantially different from the original inviscid design, due to interactions of shocks, boundary layers, and bleed. Good agreement with experimental data was obtained in many aspects. Many of the discrepancies were thought to originate primarily from 3D effects. Therefore, a balance should be struck between expending resources on a high fidelity 2D simulation, and the inherent limitations of 2D analysis. The solutions were fairly insensitive to turbulence models, grids and bleed models. Overall, the k-e turbulence model, and the bleed models based on unchoked bleed hole discharge coefficients or uniform velocity are recommended. The 2D Navier-Stokes methods appear to be a useful tool for the design and analysis of supersonic inlets, by providing a higher fidelity simulation of the inlet flowfield than inviscid methods, in a reasonable turnaround time.

Measurement of Pressure Responses in a Physical Model of a Human Head with High Shape Fidelity Based on Ct/mri Data

NASA Astrophysics Data System (ADS)

Miyazaki, Yusuke; Tachiya, Hiroshi; Anata, Kenji; Hojo, Akihiro

This study discusses a head injury mechanism in case of a human head subjected to impact, from results of impact experiments by using a physical model of a human head with high-shape fidelity. The physical model was constructed by using rapid prototyping technology from the three-dimensional CAD data, which obtained from CT/MRI images of a subject's head. As results of the experiments, positive pressure responses occurred at the impacted site, whereas negative pressure responses occurred at opposite the impacted site. Moreover, the absolute maximum value of pressure occurring at the frontal region of the intracranial space of the head model resulted in same or higher than that at the occipital site in each case that the impact force was imposed on frontal or occipital region. This result has not been showed in other study using simple shape physical models. And, the result corresponds with clinical evidences that brain contusion mainly occurs at the frontal part in each impact direction. Thus, physical model with accurate skull shape is needed to clarify the mechanism of brain contusion.

Aerodynamic design applying automatic differentiation and using robust variable fidelity optimization

NASA Astrophysics Data System (ADS)

Takemiya, Tetsushi

In modern aerospace engineering, the physics-based computational design method is becoming more important, as it is more efficient than experiments and because it is more suitable in designing new types of aircraft (e.g., unmanned aerial vehicles or supersonic business jets) than the conventional design method, which heavily relies on historical data. To enhance the reliability of the physics-based computational design method, researchers have made tremendous efforts to improve the fidelity of models. However, high-fidelity models require longer computational time, so the advantage of efficiency is partially lost. This problem has been overcome with the development of variable fidelity optimization (VFO). In VFO, different fidelity models are simultaneously employed in order to improve the speed and the accuracy of convergence in an optimization process. Among the various types of VFO methods, one of the most promising methods is the approximation management framework (AMF). In the AMF, objective and constraint functions of a low-fidelity model are scaled at a design point so that the scaled functions, which are referred to as "surrogate functions," match those of a high-fidelity model. Since scaling functions and the low-fidelity model constitutes surrogate functions, evaluating the surrogate functions is faster than evaluating the high-fidelity model. Therefore, in the optimization process, in which gradient-based optimization is implemented and thus many function calls are required, the surrogate functions are used instead of the high-fidelity model to obtain a new design point. The best feature of the AMF is that it may converge to a local optimum of the high-fidelity model in much less computational time than the high-fidelity model. However, through literature surveys and implementations of the AMF, the author xx found that (1) the AMF is very vulnerable when the computational analysis models have numerical noise, which is very common in high-fidelity models, and that (2) the AMF terminates optimization erroneously when the optimization problems have constraints. The first problem is due to inaccuracy in computing derivatives in the AMF, and the second problem is due to erroneous treatment of the trust region ratio, which sets the size of the domain for an optimization in the AMF. In order to solve the first problem of the AMF, automatic differentiation (AD) technique, which reads the codes of analysis models and automatically generates new derivative codes based on some mathematical rules, is applied. If derivatives are computed with the generated derivative code, they are analytical, and the required computational time is independent of the number of design variables, which is very advantageous for realistic aerospace engineering problems. However, if analysis models implement iterative computations such as computational fluid dynamics (CFD), which solves system partial differential equations iteratively, computing derivatives through the AD requires a massive memory size. The author solved this deficiency by modifying the AD approach and developing a more efficient implementation with CFD, and successfully applied the AD to general CFD software. In order to solve the second problem of the AMF, the governing equation of the trust region ratio, which is very strict against the violation of constraints, is modified so that it can accept the violation of constraints within some tolerance. By accepting violations of constraints during the optimization process, the AMF can continue optimization without terminating immaturely and eventually find the true optimum design point. With these modifications, the AMF is referred to as "Robust AMF," and it is applied to airfoil and wing aerodynamic design problems using Euler CFD software. The former problem has 21 design variables, and the latter 64. In both problems, derivatives computed with the proposed AD method are first compared with those computed with the finite differentiation (FD) method, and then, the Robust AMF is implemented along with the sequential quadratic programming (SQP) optimization method with only high-fidelity models. The proposed AD method computes derivatives more accurately and faster than the FD method, and the Robust AMF successfully optimizes shapes of the airfoil and the wing in a much shorter time than SQP with only high-fidelity models. These results clearly show the effectiveness of the Robust AMF. Finally, the feasibility of reducing computational time for calculating derivatives and the necessity of AMF with an optimum design point always in the feasible region are discussed as future work.

Uncertainty quantification for PZT bimorph actuators

NASA Astrophysics Data System (ADS)

Bravo, Nikolas; Smith, Ralph C.; Crews, John

2018-03-01

In this paper, we discuss the development of a high fidelity model for a PZT bimorph actuator used for micro-air vehicles, which includes the Robobee. We developed a high-fidelity model for the actuator using the homogenized energy model (HEM) framework, which quantifies the nonlinear, hysteretic, and rate-dependent behavior inherent to PZT in dynamic operating regimes. We then discussed an inverse problem on the model. We included local and global sensitivity analysis of the parameters in the high-fidelity model. Finally, we will discuss the results of Bayesian inference and uncertainty quantification on the HEM.

What Is Essential in Developmental Evaluation? On Integrity, Fidelity, Adultery, Abstinence, Impotence, Long-Term Commitment, Integrity, and Sensitivity in Implementing Evaluation Models

ERIC Educational Resources Information Center

Patton, Michael Quinn

2016-01-01

Fidelity concerns the extent to which a specific evaluation sufficiently incorporates the core characteristics of the overall approach to justify labeling that evaluation by its designated name. Fidelity has traditionally meant implementing a model in exactly the same way each time following the prescribed steps and procedures. The essential…

Effects of chromatic image statistics on illumination induced color differences.

PubMed

Lucassen, Marcel P; Gevers, Theo; Gijsenij, Arjan; Dekker, Niels

2013-09-01

We measure the color fidelity of visual scenes that are rendered under different (simulated) illuminants and shown on a calibrated LCD display. Observers make triad illuminant comparisons involving the renderings from two chromatic test illuminants and one achromatic reference illuminant shown simultaneously. Four chromatic test illuminants are used: two along the daylight locus (yellow and blue), and two perpendicular to it (red and green). The observers select the rendering having the best color fidelity, thereby indirectly judging which of the two test illuminants induces the smallest color differences compared to the reference. Both multicolor test scenes and natural scenes are studied. The multicolor scenes are synthesized and represent ellipsoidal distributions in CIELAB chromaticity space having the same mean chromaticity but different chromatic orientations. We show that, for those distributions, color fidelity is best when the vector of the illuminant change (pointing from neutral to chromatic) is parallel to the major axis of the scene's chromatic distribution. For our selection of natural scenes, which generally have much broader chromatic distributions, we measure a higher color fidelity for the yellow and blue illuminants than for red and green. Scrambled versions of the natural images are also studied to exclude possible semantic effects. We quantitatively predict the average observer response (i.e., the illuminant probability) with four types of models, differing in the extent to which they incorporate information processing by the visual system. Results show different levels of performance for the models, and different levels for the multicolor scenes and the natural scenes. Overall, models based on the scene averaged color difference have the best performance. We discuss how color constancy algorithms may be improved by exploiting knowledge of the chromatic distribution of the visual scene.

Fiscal loss and program fidelity: impact of the economic downturn on HIV/STI prevention program fidelity.

PubMed

Catania, Joseph A; Dolcini, M Margaret; Gandelman, Alice A; Narayanan, Vasudha; McKay, Virginia R

2014-03-01

The economic downturn of 2007 created significant fiscal losses for public and private agencies conducting behavioral prevention. Such macro-economic changes may influence program implementation and sustainability. We examined how public and private agencies conducting RESPECT, a brief HIV/STI (sexually transmitted infection) counseling and testing intervention, adapted to fiscal loss and how these adaptations impacted program fidelity. We collected qualitative and quantitative data in a national sample of 15 agencies experiencing fiscal loss. Using qualitative analyses, we examined how program fidelity varied with different types of adaptations. Agencies reported three levels of adaptation: agency-level, program-level, and direct fiscal remedies. Private agencies tended to use direct fiscal remedies, which were associated with higher fidelity. Some agency-level adaptations contributed to reductions in procedural fit, leading to negative staff morale and decreased confidence in program effectiveness, which in turn, contributed to poor fidelity. Findings describe a "work stress pathway" that links program fiscal losses to poor staff morale and low program fidelity.

Engagement in Training as a Mechanism to Understanding Fidelity of Implementation of the Responsive Classroom Approach.

PubMed

Wanless, Shannon B; Rimm-Kaufman, Sara E; Abry, Tashia; Larsen, Ross A; Patton, Christine L

2015-11-01

Fidelity of implementation of classroom interventions varies greatly, a reality that is concerning because higher fidelity of implementation relates to greater effectiveness of the intervention. We analyzed 126 fourth and fifth grade teachers from the treatment group of a randomized controlled trial of the Responsive Classroom® (RC) approach. Prior to training in the intervention, we assessed factors that had the potential to represent a teacher's readiness to implement with fidelity. These included teachers' observed emotional support, teacher-rated use of intervention practices, teacher-rated self-efficacy, teacher-rated collective responsibility, education level, and years of experience, and they were not directly related to observed fidelity of implementation 2 years later. Further analyses indicated, however, that RC trainers' ratings of teachers' engagement in the initial weeklong RC training mediated the relation between initial observed emotional support and later observed fidelity of implementation. We discuss these findings as a way to advance understanding of teachers' readiness to implement new interventions with fidelity.

Obtaining higher-accuracy estimates of water-rich rocks and water-poor sand dunes on Mars in active neutron experiments

NASA Astrophysics Data System (ADS)

Gabriel, T. S. J.; Hardgrove, C.; Litvak, M. L.; Nowicki, S.; Mitrofanov, I. G.; Boynton, W. V.; Fedosov, F.; Golovin, D.; Jun, I.; Mischna, M.; Tate, C. G.; Moersch, J.; Harshman, K.; Kozyrev, A.; Malakhov, A. V.; Mokrousov, M.; Nikiforov, S.; Sanin, A. B.; Vostrukhin, A.; Thompson, L. M.

2017-12-01

The Dynamic Albedo of Neutrons (DAN) experiment on the Mars Science Laboratory Curiosity Rover delivers high-energy (14.1 MeV) pulses of neutrons into the surface when operating in "active" mode. Neutrons are moderated in the subsurface and return to two detectors to provide a time-of-flight profile in 64 time-bins in epithermal and thermal energy ranges. Results are compared to simulations of the experiment in the Monte Carlo N-Particle Transport Code where several aspects are modeled including the DAN detectors, neutron source, rover components, and underlying rock. Models can be improved by increasing the fidelity of the rock geochemistry as informed by instruments including the Alpha Particle X-Ray Spectrometer (APXS). Furthermore, increasing the fidelity of the rock morphology in models is enabled by the suite of imaging instruments on the rover.To rapidly interpret DAN data a set of pre-simulated generic rock density and bulk geochemistry models are compared to several DAN active observations. While, to first order, this methodology provides an indication of significant geochemical changes in the subsurface, higher-fidelity models should be used to provide accurate constraints on water content, depth of geologic layers, or abundance of neutron absorbers. For example, in high-silicon, low-iron rocks observed along the rover's traverse, generic models can differ by several wt%H2O from models that use APXS measurements of nearby drill samples. Accurate measurements of high-silicon targets are necessary in outlining the extent of aqueous alteration and hydrothermal activity in Gale Crater. Additionally, we find that for DAN active experiments over sand dunes best-fit models can differ by greater than 0.5 wt%HO when the upper layer density is reduced by 0.6 g/cm3 to account for the low-bulk density of sand. In areas where the rock geochemistry differs little from generic models the difference in results is expectedly less disparate. We report refined wt%HO values for high-silicon, aqueously-altered rock and comparatively dry sand dunes along the rover traverse. We also outline the methodology for providing accurate geochemical and morphological constraints using DAN active measurements.

Development and Implementation of CFD-Informed Models for the Advanced Subchannel Code CTF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blyth, Taylor S.; Avramova, Maria

The research described in this PhD thesis contributes to the development of efficient methods for utilization of high-fidelity models and codes to inform low-fidelity models and codes in the area of nuclear reactor core thermal-hydraulics. The objective is to increase the accuracy of predictions of quantities of interests using high-fidelity CFD models while preserving the efficiency of low-fidelity subchannel core calculations. An original methodology named Physics- based Approach for High-to-Low Model Information has been further developed and tested. The overall physical phenomena and corresponding localized effects, which are introduced by the presence of spacer grids in light water reactor (LWR)more » cores, are dissected in corresponding four building basic processes, and corresponding models are informed using high-fidelity CFD codes. These models are a spacer grid-directed cross-flow model, a grid-enhanced turbulent mixing model, a heat transfer enhancement model, and a spacer grid pressure loss model. The localized CFD-models are developed and tested using the CFD code STAR-CCM+, and the corresponding global model development and testing in sub-channel formulation is performed in the thermal- hydraulic subchannel code CTF. The improved CTF simulations utilize data-files derived from CFD STAR-CCM+ simulation results covering the spacer grid design desired for inclusion in the CTF calculation. The current implementation of these models is examined and possibilities for improvement and further development are suggested. The validation experimental database is extended by including the OECD/NRC PSBT benchmark data. The outcome is an enhanced accuracy of CTF predictions while preserving the computational efficiency of a low-fidelity subchannel code.« less

Development and Implementation of CFD-Informed Models for the Advanced Subchannel Code CTF

NASA Astrophysics Data System (ADS)

Blyth, Taylor S.

The research described in this PhD thesis contributes to the development of efficient methods for utilization of high-fidelity models and codes to inform low-fidelity models and codes in the area of nuclear reactor core thermal-hydraulics. The objective is to increase the accuracy of predictions of quantities of interests using high-fidelity CFD models while preserving the efficiency of low-fidelity subchannel core calculations. An original methodology named Physics-based Approach for High-to-Low Model Information has been further developed and tested. The overall physical phenomena and corresponding localized effects, which are introduced by the presence of spacer grids in light water reactor (LWR) cores, are dissected in corresponding four building basic processes, and corresponding models are informed using high-fidelity CFD codes. These models are a spacer grid-directed cross-flow model, a grid-enhanced turbulent mixing model, a heat transfer enhancement model, and a spacer grid pressure loss model. The localized CFD-models are developed and tested using the CFD code STAR-CCM+, and the corresponding global model development and testing in sub-channel formulation is performed in the thermal-hydraulic subchannel code CTF. The improved CTF simulations utilize data-files derived from CFD STAR-CCM+ simulation results covering the spacer grid design desired for inclusion in the CTF calculation. The current implementation of these models is examined and possibilities for improvement and further development are suggested. The validation experimental database is extended by including the OECD/NRC PSBT benchmark data. The outcome is an enhanced accuracy of CTF predictions while preserving the computational efficiency of a low-fidelity subchannel code.

Feasibility and fidelity of practising surgical fixation on a virtual ulna bone

PubMed Central

LeBlanc, Justin; Hutchison, Carol; Hu, Yaoping; Donnon, Tyrone

2013-01-01

Background Surgical simulators provide a safe environment to learn and practise psychomotor skills. A goal for these simulators is to achieve high levels of fidelity. The purpose of this study was to develop a reliable surgical simulator fidelity questionnaire and to assess whether a newly developed virtual haptic simulator for fixation of an ulna has comparable levels of fidelity as Sawbones. Methods Simulator fidelity questionnaires were developed. We performed a stratified randomized study with surgical trainees. They performed fixation of the ulna using a virtual simulator and Sawbones. They completed the fidelity questionnaires after each procedure. Results Twenty-two trainees participated in the study. The reliability of the fidelity questionnaire for each separate domain (environment, equipment, psychological) was Cronbach α greater than 0.70, except for virtual environment. The Sawbones had significantly higher levels of fidelity than the virtual simulator (p < 0.001) with a large effect size difference (Cohen d < 1.3). Conclusion The newly developed fidelity questionnaire is a reliable tool that can potentially be used to determine the fidelity of other surgical simulators. Increasing the fidelity of this virtual simulator is required before its use as a training tool for surgical fixation. The virtual simulator brings with it the added benefits of repeated, independent safe use with immediate, objective feedback and the potential to alter the complexity of the skill. PMID:23883510

Challenges of Applying a Comprehensive Model of Intervention Fidelity

PubMed Central

Bosak, Kelly; Pozehl, Bunny; Yates, Bernice

2014-01-01

Applying a comprehensive model of fidelity to interventions delivered by Information and Communication Technology (ICT) has multiple challenges. Fidelity must be considered in the design, implementation, evaluation, and reporting of the intervention. The fidelity strategies must address the unique aspects of the technology, including training providers to instruct participants to use the technology and to provide standardized feedback, rather than deliver the intervention in-person. Other challenges include the nonspecific effects resulting from participants accessing unintended content in interventions delivered by the Internet. ICT allows participant receipt and enactment of intervention skills to be assessed by electronic evidence, rather than in-person observation. Interventions using ICT, such as the Internet are unique, and there is less control of participant interaction with various electronic components. Monitoring participant use and providing standardized feedback for receipt and enactment of intervention skills is key to ensuring intervention fidelity. The final challenges involve evaluating and reporting fidelity. PMID:21474676

Effects of simulation fidelity on user experience in virtual fear of public speaking training - an experimental study.

PubMed

Poeschl, Sandra; Doering, Nicola

2014-01-01

Realistic models in virtual reality training applications are considered to positively influence presence and performance. The experimental study presented, analyzed the effect of simulation fidelity (static vs. animated audience) on presence as a prerequisite for performance in a prototype virtual fear of public speaking application with a sample of N = 40 academic non-phobic users. Contrary to the state of research, no influence was shown on virtual presence and perceived realism, but an animated audience led to significantly higher effects in anxiety during giving a talk. Although these findings could be explained by an application that might not have been realistic enough, they still question the role of presence as a mediating factor in virtual exposure applications.

Gearbox Reliability Collaborative Investigation of High-Speed-Shaft Bearing Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, Jonathan; Guo, Yi

2016-06-01

The loads and contact stresses in the bearings of the high speed shaft section of the Gearbox Reliability Collaborative gearbox are examined in this paper. The loads were measured though strain gauges installed on the bearing outer races during dynamometer testing of the gearbox. Loads and stresses were also predicted with a simple analytical model and higher-fidelity commercial models. The experimental data compared favorably to each model, and bearing stresses were below thresholds for contact fatigue and axial cracking.

The relationship between school-level characteristics and implementation fidelity of a coordinated school health childhood obesity prevention intervention.

PubMed

Lederer, Alyssa M; King, Mindy H; Sovinski, Danielle; Seo, Dong-Chul; Kim, Nayoung

2015-01-01

Curtailing childhood obesity is a public health imperative. Although multicomponent school-based programs reduce obesity among children, less is known about the implementation fidelity of these interventions. This study examines process evaluation findings for the Healthy, Energetic Ready, Outstanding, Enthusiastic, Schools (HEROES) Initiative, a tri-state school-based childhood obesity prevention intervention based on the coordinated school health (CSH) model. Site visits were conducted that included key stakeholder interviews, observation, and document review. Scores were given for 8 domains, and a total implementation score was calculated. Two-way analyses of variance were conducted to examine the relationship of 4 school-level characteristics: elementary vs. middle/high schools, public vs. private schools, district vs. building level implementation, and socioeconomic status on each implementation area. Overall, schools had high fidelity scores, although some domains were implemented more successfully than others. Three school-level characteristics were associated with 1 or more domains, with elementary schools and schools implementing at the building level consistently having higher implementation scores than their counterparts. Process evaluation findings provide insight into successes and challenges schools implementing the CSH approach may encounter. Although preliminary, these findings on school-level characteristics establish a new area of research related to school-based childhood obesity prevention programs' implementation fidelity. © 2014, American School Health Association.

Surrogate based wind farm layout optimization using manifold mapping

NASA Astrophysics Data System (ADS)

Kaja Kamaludeen, Shaafi M.; van Zuijle, Alexander; Bijl, Hester

2016-09-01

High computational cost associated with the high fidelity wake models such as RANS or LES serves as a primary bottleneck to perform a direct high fidelity wind farm layout optimization (WFLO) using accurate CFD based wake models. Therefore, a surrogate based multi-fidelity WFLO methodology (SWFLO) is proposed. The surrogate model is built using an SBO method referred as manifold mapping (MM). As a verification, optimization of spacing between two staggered wind turbines was performed using the proposed surrogate based methodology and the performance was compared with that of direct optimization using high fidelity model. Significant reduction in computational cost was achieved using MM: a maximum computational cost reduction of 65%, while arriving at the same optima as that of direct high fidelity optimization. The similarity between the response of models, the number of mapping points and its position, highly influences the computational efficiency of the proposed method. As a proof of concept, realistic WFLO of a small 7-turbine wind farm is performed using the proposed surrogate based methodology. Two variants of Jensen wake model with different decay coefficients were used as the fine and coarse model. The proposed SWFLO method arrived at the same optima as that of the fine model with very less number of fine model simulations.

Utilizing Three-Dimensional Printing Technology to Assess the Feasibility of High-Fidelity Synthetic Ventricular Septal Defect Models for Simulation in Medical Education.

PubMed

Costello, John P; Olivieri, Laura J; Krieger, Axel; Thabit, Omar; Marshall, M Blair; Yoo, Shi-Joon; Kim, Peter C; Jonas, Richard A; Nath, Dilip S

2014-07-01

The current educational approach for teaching congenital heart disease (CHD) anatomy to students involves instructional tools and techniques that have significant limitations. This study sought to assess the feasibility of utilizing present-day three-dimensional (3D) printing technology to create high-fidelity synthetic heart models with ventricular septal defect (VSD) lesions and applying these models to a novel, simulation-based educational curriculum for premedical and medical students. Archived, de-identified magnetic resonance images of five common VSD subtypes were obtained. These cardiac images were then segmented and built into 3D computer-aided design models using Mimics Innovation Suite software. An Objet500 Connex 3D printer was subsequently utilized to print a high-fidelity heart model for each VSD subtype. Next, a simulation-based educational curriculum using these heart models was developed and implemented in the instruction of 29 premedical and medical students. Assessment of this curriculum was undertaken with Likert-type questionnaires. High-fidelity VSD models were successfully created utilizing magnetic resonance imaging data and 3D printing. Following instruction with these high-fidelity models, all students reported significant improvement in knowledge acquisition (P < .0001), knowledge reporting (P < .0001), and structural conceptualization (P < .0001) of VSDs. It is feasible to use present-day 3D printing technology to create high-fidelity heart models with complex intracardiac defects. Furthermore, this tool forms the foundation for an innovative, simulation-based educational approach to teach students about CHD and creates a novel opportunity to stimulate their interest in this field. © The Author(s) 2014.

A simple, analytical, axisymmetric microburst model for downdraft estimation

NASA Technical Reports Server (NTRS)

Vicroy, Dan D.

1991-01-01

A simple analytical microburst model was developed for use in estimating vertical winds from horizontal wind measurements. It is an axisymmetric, steady state model that uses shaping functions to satisfy the mass continuity equation and simulate boundary layer effects. The model is defined through four model variables: the radius and altitude of the maximum horizontal wind, a shaping function variable, and a scale factor. The model closely agrees with a high fidelity analytical model and measured data, particularily in the radial direction and at lower altitudes. At higher altitudes, the model tends to overestimate the wind magnitude relative to the measured data.

Hydropower Optimization Using Artificial Neural Network Surrogate Models of a High-Fidelity Hydrodynamics and Water Quality Model

NASA Astrophysics Data System (ADS)

Shaw, Amelia R.; Smith Sawyer, Heather; LeBoeuf, Eugene J.; McDonald, Mark P.; Hadjerioua, Boualem

2017-11-01

Hydropower operations optimization subject to environmental constraints is limited by challenges associated with dimensionality and spatial and temporal resolution. The need for high-fidelity hydrodynamic and water quality models within optimization schemes is driven by improved computational capabilities, increased requirements to meet specific points of compliance with greater resolution, and the need to optimize operations of not just single reservoirs but systems of reservoirs. This study describes an important advancement for computing hourly power generation schemes for a hydropower reservoir using high-fidelity models, surrogate modeling techniques, and optimization methods. The predictive power of the high-fidelity hydrodynamic and water quality model CE-QUAL-W2 is successfully emulated by an artificial neural network, then integrated into a genetic algorithm optimization approach to maximize hydropower generation subject to constraints on dam operations and water quality. This methodology is applied to a multipurpose reservoir near Nashville, Tennessee, USA. The model successfully reproduced high-fidelity reservoir information while enabling 6.8% and 6.6% increases in hydropower production value relative to actual operations for dissolved oxygen (DO) limits of 5 and 6 mg/L, respectively, while witnessing an expected decrease in power generation at more restrictive DO constraints. Exploration of simultaneous temperature and DO constraints revealed capability to address multiple water quality constraints at specified locations. The reduced computational requirements of the new modeling approach demonstrated an ability to provide decision support for reservoir operations scheduling while maintaining high-fidelity hydrodynamic and water quality information as part of the optimization decision support routines.

Hydropower Optimization Using Artificial Neural Network Surrogate Models of a High-Fidelity Hydrodynamics and Water Quality Model

DOE PAGES

Shaw, Amelia R.; Sawyer, Heather Smith; LeBoeuf, Eugene J.; ...

2017-10-24

Hydropower operations optimization subject to environmental constraints is limited by challenges associated with dimensionality and spatial and temporal resolution. The need for high-fidelity hydrodynamic and water quality models within optimization schemes is driven by improved computational capabilities, increased requirements to meet specific points of compliance with greater resolution, and the need to optimize operations of not just single reservoirs but systems of reservoirs. This study describes an important advancement for computing hourly power generation schemes for a hydropower reservoir using high-fidelity models, surrogate modeling techniques, and optimization methods. The predictive power of the high-fidelity hydrodynamic and water quality model CE-QUAL-W2more » is successfully emulated by an artificial neural network, then integrated into a genetic algorithm optimization approach to maximize hydropower generation subject to constraints on dam operations and water quality. This methodology is applied to a multipurpose reservoir near Nashville, Tennessee, USA. The model successfully reproduced high-fidelity reservoir information while enabling 6.8% and 6.6% increases in hydropower production value relative to actual operations for dissolved oxygen (DO) limits of 5 and 6 mg/L, respectively, while witnessing an expected decrease in power generation at more restrictive DO constraints. Exploration of simultaneous temperature and DO constraints revealed capability to address multiple water quality constraints at specified locations. Here, the reduced computational requirements of the new modeling approach demonstrated an ability to provide decision support for reservoir operations scheduling while maintaining high-fidelity hydrodynamic and water quality information as part of the optimization decision support routines.« less

Hydropower Optimization Using Artificial Neural Network Surrogate Models of a High-Fidelity Hydrodynamics and Water Quality Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaw, Amelia R.; Sawyer, Heather Smith; LeBoeuf, Eugene J.

Hydropower operations optimization subject to environmental constraints is limited by challenges associated with dimensionality and spatial and temporal resolution. The need for high-fidelity hydrodynamic and water quality models within optimization schemes is driven by improved computational capabilities, increased requirements to meet specific points of compliance with greater resolution, and the need to optimize operations of not just single reservoirs but systems of reservoirs. This study describes an important advancement for computing hourly power generation schemes for a hydropower reservoir using high-fidelity models, surrogate modeling techniques, and optimization methods. The predictive power of the high-fidelity hydrodynamic and water quality model CE-QUAL-W2more » is successfully emulated by an artificial neural network, then integrated into a genetic algorithm optimization approach to maximize hydropower generation subject to constraints on dam operations and water quality. This methodology is applied to a multipurpose reservoir near Nashville, Tennessee, USA. The model successfully reproduced high-fidelity reservoir information while enabling 6.8% and 6.6% increases in hydropower production value relative to actual operations for dissolved oxygen (DO) limits of 5 and 6 mg/L, respectively, while witnessing an expected decrease in power generation at more restrictive DO constraints. Exploration of simultaneous temperature and DO constraints revealed capability to address multiple water quality constraints at specified locations. Here, the reduced computational requirements of the new modeling approach demonstrated an ability to provide decision support for reservoir operations scheduling while maintaining high-fidelity hydrodynamic and water quality information as part of the optimization decision support routines.« less

High fidelity quantum gates with vibrational qubits.

PubMed

Berrios, Eduardo; Gruebele, Martin; Shyshlov, Dmytro; Wang, Lei; Babikov, Dmitri

2012-11-26

Physical implementation of quantum gates acting on qubits does not achieve a perfect fidelity of 1. The actual output qubit may not match the targeted output of the desired gate. According to theoretical estimates, intrinsic gate fidelities >99.99% are necessary so that error correction codes can be used to achieve perfect fidelity. Here we test what fidelity can be accomplished for a CNOT gate executed by a shaped ultrafast laser pulse interacting with vibrational states of the molecule SCCl(2). This molecule has been used as a test system for low-fidelity calculations before. To make our test more stringent, we include vibrational levels that do not encode the desired qubits but are close enough in energy to interfere with population transfer by the laser pulse. We use two complementary approaches: optimal control theory determines what the best possible pulse can do; a more constrained physical model calculates what an experiment likely can do. Optimal control theory finds pulses with fidelity >0.9999, in excess of the quantum error correction threshold with 8 × 10(4) iterations. On the other hand, the physical model achieves only 0.9992 after 8 × 10(4) iterations. Both calculations converge as an inverse power law toward unit fidelity after >10(2) iterations/generations. In principle, the fidelities necessary for quantum error correction are reachable with qubits encoded by molecular vibrations. In practice, it will be challenging with current laboratory instrumentation because of slow convergence past fidelities of 0.99.

Testing the Predictive Capability of the High-Fidelity Generalized Method of Cells Using an Efficient Reformulation

NASA Technical Reports Server (NTRS)

Arnold, Steven M. (Technical Monitor); Bansal, Yogesh; Pindera, Marek-Jerzy

2004-01-01

The High-Fidelity Generalized Method of Cells is a new micromechanics model for unidirectionally reinforced periodic multiphase materials that was developed to overcome the original model's shortcomings. The high-fidelity version predicts the local stress and strain fields with dramatically greater accuracy relative to the original model through the use of a better displacement field representation. Herein, we test the high-fidelity model's predictive capability in estimating the elastic moduli of periodic composites characterized by repeating unit cells obtained by rotation of an infinite square fiber array through an angle about the fiber axis. Such repeating unit cells may contain a few or many fibers, depending on the rotation angle. In order to analyze such multi-inclusion repeating unit cells efficiently, the high-fidelity micromechanics model's framework is reformulated using the local/global stiffness matrix approach. The excellent agreement with the corresponding results obtained from the standard transformation equations confirms the new model's predictive capability for periodic composites characterized by multi-inclusion repeating unit cells lacking planes of material symmetry. Comparison of the effective moduli and local stress fields with the corresponding results obtained from the original Generalized Method of Cells dramatically highlights the original model's shortcomings for certain classes of unidirectional composites.

The Role of School Context in Implementing a Statewide Anti-Bullying Policy and Protecting Students

PubMed Central

Hall, William J.; Chapman, Mimi V.

2016-01-01

Bullying is a significant problem in U.S. schools. Policies have been developed to reduce bullying, yet policy implementation by educators is an essential yet difficult and complex process. Few studies have investigated factors that act as barriers to or facilitators of bullying policy implementation and teacher protection of students. This study examined the influence of school context on educators’ capacity to implement a statewide bullying law and protect students from bullying following the enactment of the policy. Data were collected from 505 educators in 324 schools. School administrators tended to rate fidelity of policy implementation and teacher protection of students higher than teachers, education support professionals, and student service professionals. Policy implementation fidelity scores were higher in high schools than elementary schools. School size and the prevalence of student suspensions were inversely related to implementation fidelity. Higher levels of teacher protection were reported in elementary schools.

The Role of School Context in Implementing a Statewide Anti-Bullying Policy and Protecting Students.

PubMed

Hall, William J; Chapman, Mimi V

2018-06-01

Bullying is a significant problem in U.S. schools. Policies have been developed to reduce bullying, yet policy implementation by educators is an essential yet difficult and complex process. Few studies have investigated factors that act as barriers to or facilitators of bullying policy implementation and teacher protection of students. This study examined the influence of school context on educators' capacity to implement a statewide bullying law and protect students from bullying following the enactment of the policy. Data were collected from 505 educators in 324 schools. School administrators tended to rate fidelity of policy implementation and teacher protection of students higher than teachers, education support professionals, and student service professionals. Policy implementation fidelity scores were higher in high schools than elementary schools. School size and the prevalence of student suspensions were inversely related to implementation fidelity. Higher levels of teacher protection were reported in elementary schools.

Focus on Implementation: Assessing and Promoting Treatment Fidelity

ERIC Educational Resources Information Center

Collier-Meek, Melissa A.; Fallon, Lindsay M.; Sanetti, Lisa M. H.; Maggin, Daniel M.

2013-01-01

Implementation, or treatment fidelity, is the link between evidence-based interventions and changes in student outcomes. Although higher levels of implementation are generally associated with more efficient improvements in student outcomes, research indicates that many adults struggle to consistently implement student interventions. As school…

Assessing the competing roles of model resolution and meteorological forcing fidelity in hyperresolution simulations of snowpack and streamflow in the southern Rocky Mountains

NASA Astrophysics Data System (ADS)

Gochis, D. J.; Dugger, A. L.; Karsten, L. R.; Barlage, M. J.; Sampson, K. M.; Yu, W.; Pan, L.; McCreight, J. L.; Howard, K.; Busto, J.; Deems, J. S.

2017-12-01

Hydrometeorological processes vary over comparatively short length scales in regions of complex terrain such as the southern Rocky Mountains. Changes in temperature, precipitation, wind and solar radiation can vary significantly across elevation gradients, terrain landform and land cover conditions throughout the region. Capturing such variability in hydrologic models can necessitate the utilization of so-called `hyper-resolution' spatial meshes with effective element spacings of less than 100m. However, it is often difficult to obtain meteorological forcings of high quality in such regions at those resolutions which can result in significant uncertainty in fundamental in hydrologic model inputs. In this study we examine the comparative influences of meteorological forcing data fidelity and spatial resolution on seasonal simulations of snowpack evolution, runoff and streamflow in a set of high mountain watersheds in southern Colorado. We utilize the operational, NOAA National Water Model configuration of the community WRF-Hydro system as a baseline and compare against it, additional model scenarios with differing specifications of meteorological forcing data, with and without topographic downscaling adjustments applied, with and without experimental high resolution radar derived precipitation estimates and with WRF-Hydro configurations of progressively finer spatial resolution. The results suggest significant influence from and importance of meteorological downscaling techniques in controlling spatial distributions of meltout and runoff timing. The use of radar derived precipitation exhibits clear sensitivity on hydrologic simulation skill compared with the use of coarser resolution, background precipitation analyses. Advantages and disadvantages of the utilization of progressively higher resolution model configurations both in terms of computational requirements and model fidelity are also discussed.

Orbit Stability of OSIRIS-REx in the Vicinity of Bennu Using a High-Fidelity Solar Radiation Model

NASA Technical Reports Server (NTRS)

Williams, Trevor; Hughes, Kyle; Mashiku, Alinda; Longuski, James

2015-01-01

The OSIRIS-REx mission (Origins Spectral Interpretation Resource Identification Security Regolith EXPlorer) is an asteroid sample return mission to Bennu (RQ36) that is scheduled to launch in 2016. The planned science operations precluding the small retrieval involve operations in terminator orbits (orbit plane is perpendicular to the sun). Over longer durations the solar radiation pressure (SRP) perturbs the orbit causing it to precess. Our work involves: modeling high fidelity SRP model to capture the perturbations during attitude changes; design a stable orbit from the high fidelity models to analyze the stability over time.

An Analysis Technique/Automated Tool for Comparing and Tracking Analysis Modes of Different Finite Element Models

NASA Technical Reports Server (NTRS)

Towner, Robert L.; Band, Jonathan L.

2012-01-01

An analysis technique was developed to compare and track mode shapes for different Finite Element Models. The technique may be applied to a variety of structural dynamics analyses, including model reduction validation (comparing unreduced and reduced models), mode tracking for various parametric analyses (e.g., launch vehicle model dispersion analysis to identify sensitivities to modal gain for Guidance, Navigation, and Control), comparing models of different mesh fidelity (e.g., a coarse model for a preliminary analysis compared to a higher-fidelity model for a detailed analysis) and mode tracking for a structure with properties that change over time (e.g., a launch vehicle from liftoff through end-of-burn, with propellant being expended during the flight). Mode shapes for different models are compared and tracked using several numerical indicators, including traditional Cross-Orthogonality and Modal Assurance Criteria approaches, as well as numerical indicators obtained by comparing modal strain energy and kinetic energy distributions. This analysis technique has been used to reliably identify correlated mode shapes for complex Finite Element Models that would otherwise be difficult to compare using traditional techniques. This improved approach also utilizes an adaptive mode tracking algorithm that allows for automated tracking when working with complex models and/or comparing a large group of models.

High-Fidelity Simulations of Electromagnetic Propagation and RF Communication Systems

DTIC Science & Technology

2017-05-01

addition to high -fidelity RF propagation modeling, lower-fidelity mod- els, which are less computationally burdensome, are available via a C++ API...expensive to perform, requiring roughly one hour of computer time with 36 available cores and ray tracing per- formed by a single high -end GPU...ER D C TR -1 7- 2 Military Engineering Applied Research High -Fidelity Simulations of Electromagnetic Propagation and RF Communication

DDDAMS-based Urban Surveillance and Crowd Control via UAVs and UGVs

DTIC Science & Technology

2015-12-04

for crowd dynamics modeling by incorporating multi-resolution data, where a grid-based method is used to model crowd motion with UAVs’ low -resolution...information and more computational intensive (and time-consuming). Given that the deployment of fidelity selection results in simulation faces computational... low fidelity information FOV y (A) DR x (A) DR y (A) Not detected high fidelity information Table 1: Parameters for UAV and UGV for their detection

Physiological Based Simulator Fidelity Design Guidance

NASA Technical Reports Server (NTRS)

Schnell, Thomas; Hamel, Nancy; Postnikov, Alex; Hoke, Jaclyn; McLean, Angus L. M. Thom, III

2012-01-01

The evolution of the role of flight simulation has reinforced assumptions in aviation that the degree of realism in a simulation system directly correlates to the training benefit, i.e., more fidelity is always better. The construct of fidelity has several dimensions, including physical fidelity, functional fidelity, and cognitive fidelity. Interaction of different fidelity dimensions has an impact on trainee immersion, presence, and transfer of training. This paper discusses research results of a recent study that investigated if physiological-based methods could be used to determine the required level of simulator fidelity. Pilots performed a relatively complex flight task consisting of mission task elements of various levels of difficulty in a fixed base flight simulator and a real fighter jet trainer aircraft. Flight runs were performed using one forward visual channel of 40 deg. field of view for the lowest level of fidelity, 120 deg. field of view for the middle level of fidelity, and unrestricted field of view and full dynamic acceleration in the real airplane. Neuro-cognitive and physiological measures were collected under these conditions using the Cognitive Avionics Tool Set (CATS) and nonlinear closed form models for workload prediction were generated based on these data for the various mission task elements. One finding of the work described herein is that simple heart rate is a relatively good predictor of cognitive workload, even for short tasks with dynamic changes in cognitive loading. Additionally, we found that models that used a wide range of physiological and neuro-cognitive measures can further boost the accuracy of the workload prediction.

Investigating variations in implementation fidelity of an organizational-level occupational health intervention.

PubMed

Augustsson, Hanna; von Thiele Schwarz, Ulrica; Stenfors-Hayes, Terese; Hasson, Henna

2015-06-01

The workplace has been suggested as an important arena for health promotion, but little is known about how the organizational setting influences the implementation of interventions. The aims of this study are to evaluate implementation fidelity in an organizational-level occupational health intervention and to investigate possible explanations for variations in fidelity between intervention units. The intervention consisted of an integration of health promotion, occupational health and safety, and a system for continuous improvements (Kaizen) and was conducted in a quasi-experimental design at a Swedish hospital. Implementation fidelity was evaluated with the Conceptual Framework for Implementation Fidelity and implementation factors used to investigate variations in fidelity with the Framework for Evaluating Organizational-level Interventions. A multi-method approach including interviews, Kaizen notes, and questionnaires was applied. Implementation fidelity differed between units even though the intervention was introduced and supported in the same way. Important differences in all elements proposed in the model for evaluating organizational-level interventions, i.e., context, intervention, and mental models, were found to explain the differences in fidelity. Implementation strategies may need to be adapted depending on the local context. Implementation fidelity, as well as pre-intervention implementation elements, is likely to affect the implementation success and needs to be assessed in intervention research. The high variation in fidelity across the units indicates the need for adjustments to the type of designs used to assess the effects of interventions. Thus, rather than using designs that aim to control variation, it may be necessary to use those that aim at exploring and explaining variation, such as adapted study designs.

Modeling movement and fidelity of American black ducks

USGS Publications Warehouse

Zimpfer, N.L.; Conroy, M.J.

2006-01-01

Spatial relationships among stocks of breeding waterfowl can be an important component of harvest management. Prediction and optimal harvest management under adaptive harvest management (AHM) requires information on the spatial relationships among breeding populations (fidelity and inter-year exchange), as well as rates of movements from breeding to harvest regions. We used band-recovery data to develop a model to estimate probabilities of movement for American black ducks (Anas rubripes) among 3 Canadian breeding strata and 6 harvest regions (3 in Canada, and 3 in the United States) over the period 1965-1998. Model selection criteria suggested that models containing area-, year-, and age-specific recovery rates with area- and sex-specific movement rates were the best for modeling movement. Movement by males to southern harvest areas was variable depending on the originating area. Males from the western breeding area predominantly moved to the Mississippi Flyway or southern Atlantic Flyway (??ij = 0.353, SE = 0.0187 and ??ij = 0.473, SE = 0.037, respectively), whereas males that originated in the eastern and central breeding strata moved to the northern Atlantic flyway (??ij = 0.842, SE = 0.010 and ??ij = 0.578, SE = 0.0222, respectively). We used combined recoveries and recaptures in Program MARK to estimate fidelity to the 3 Canadian breeding strata. Information criteria identified a model containing sex- and age-specific fidelity for black ducks. Estimates of fidelity were 0.9695 (SE = 0.0249) and 0.9554 (SE = 0.0434) for adult males and females, respectively. Estimates of fidelity for juveniles were slightly lower at 0.9210 (SE = 0.0931) and 0.8870 (SE = 0.0475) for males and females, respectively. These models have application to the development of spatially stratified black duck harvest management models for use in AHM.

Fidelity Moderates the Association Between Negative Condom Attitudes and Outcome Behavior in an Evidence-Based Sexual Risk Reduction Intervention for Female Sex Workers.

PubMed

Pitpitan, Eileen V; Chavarin, Claudia V; Semple, Shirley J; Mendoza, Doroteo; Rodriguez, Carlos Magis; Staines, Hugo; Aarons, Gregory A; Patterson, Thomas L

2017-06-01

Intervention fidelity and participant-level variables, such as negative attitudes towards condoms, are important variables to consider in the successful implementation of evidence-based HIV prevention interventions. Mujer Segura is an intervention that has been shown to be efficacious at reducing condomless sex for female sex workers (FSWs) in Mexico [1]. We examined main effects of fidelity, negative condom attitudes, and their interaction on the effectiveness of the Mujer Segura intervention at reducing condomless sex at intervention follow-up. Of the FSWs recruited from 13 cities across Mexico, 528 participated in the Mujer Segura intervention. We measured negative condom attitudes at baseline (comprising of beliefs and outcome evaluations) and condomless sex with clients at baseline and 6-month follow-up. Fidelity was measured by a fidelity checklist completed by independent raters; the sum of potentially 43 total elements completed by the counselor constituted fidelity. Complete fidelity was found in only 15.1% (n = 73) of sessions. There was no significant main effect of intervention fidelity on condomless sex with clients at follow-up. There was a significant and positive main effect of negative condom attitudes and a significant two-way interaction. At lower levels of fidelity, negative condom attitudes predicted greater condomless sex acts, whereas at higher levels of fidelity, the effect of condom attitudes became weaker. The results also indicated that the interaction between negative condom attitudes and fidelity were driven primarily by negative condom beliefs, as opposed to negative condom outcome evaluations. Ensuring treatment fidelity in an HIV prevention intervention is particularly important when participants have negative attitudes towards condoms.

A Kinematic Calibration Process for Flight Robotic Arms

NASA Technical Reports Server (NTRS)

Collins, Curtis L.; Robinson, Matthew L.

2013-01-01

The Mars Science Laboratory (MSL) robotic arm is ten times more massive than any Mars robotic arm before it, yet with similar accuracy and repeatability positioning requirements. In order to assess and validate these requirements, a higher-fidelity model and calibration processes were needed. Kinematic calibration of robotic arms is a common and necessary process to ensure good positioning performance. Most methodologies assume a rigid arm, high-accuracy data collection, and some kind of optimization of kinematic parameters. A new detailed kinematic and deflection model of the MSL robotic arm was formulated in the design phase and used to update the initial positioning and orientation accuracy and repeatability requirements. This model included a higher-fidelity link stiffness matrix representation, as well as a link level thermal expansion model. In addition, it included an actuator backlash model. Analytical results highlighted the sensitivity of the arm accuracy to its joint initialization methodology. Because of this, a new technique for initializing the arm joint encoders through hardstop calibration was developed. This involved selecting arm configurations to use in Earth-based hardstop calibration that had corresponding configurations on Mars with the same joint torque to ensure repeatability in the different gravity environment. The process used to collect calibration data for the arm included the use of multiple weight stand-in turrets with enough metrology targets to reconstruct the full six-degree-of-freedom location of the rover and tool frames. The follow-on data processing of the metrology data utilized a standard differential formulation and linear parameter optimization technique.

Assessment of synthetic image fidelity

NASA Astrophysics Data System (ADS)

Mitchell, Kevin D.; Moorhead, Ian R.; Gilmore, Marilyn A.; Watson, Graham H.; Thomson, Mitch; Yates, T.; Troscianko, Tomasz; Tolhurst, David J.

2000-07-01

Computer generated imagery is increasingly used for a wide variety of purposes ranging from computer games to flight simulators to camouflage and sensor assessment. The fidelity required for this imagery is dependent on the anticipated use - for example when used for camouflage design it must be physically correct spectrally and spatially. The rendering techniques used will also depend upon the waveband being simulated, spatial resolution of the sensor and the required frame rate. Rendering of natural outdoor scenes is particularly demanding, because of the statistical variation in materials and illumination, atmospheric effects and the complex geometric structures of objects such as trees. The accuracy of the simulated imagery has tended to be assessed subjectively in the past. First and second order statistics do not capture many of the essential characteristics of natural scenes. Direct pixel comparison would impose an unachievable demand on the synthetic imagery. For many applications, such as camouflage design, it is important that nay metrics used will work in both visible and infrared wavebands. We are investigating a variety of different methods of comparing real and synthetic imagery and comparing synthetic imagery rendered to different levels of fidelity. These techniques will include neural networks (ICA), higher order statistics and models of human contrast perception. This paper will present an overview of the analyses we have carried out and some initial results along with some preliminary conclusions regarding the fidelity of synthetic imagery.

An Agent-Based Model for Analyzing Control Policies and the Dynamic Service-Time Performance of a Capacity-Constrained Air Traffic Management Facility

NASA Technical Reports Server (NTRS)

Conway, Sheila R.

2006-01-01

Simple agent-based models may be useful for investigating air traffic control strategies as a precursory screening for more costly, higher fidelity simulation. Of concern is the ability of the models to capture the essence of the system and provide insight into system behavior in a timely manner and without breaking the bank. The method is put to the test with the development of a model to address situations where capacity is overburdened and potential for propagation of the resultant delay though later flights is possible via flight dependencies. The resultant model includes primitive representations of principal air traffic system attributes, namely system capacity, demand, airline schedules and strategy, and aircraft capability. It affords a venue to explore their interdependence in a time-dependent, dynamic system simulation. The scope of the research question and the carefully-chosen modeling fidelity did allow for the development of an agent-based model in short order. The model predicted non-linear behavior given certain initial conditions and system control strategies. Additionally, a combination of the model and dimensionless techniques borrowed from fluid systems was demonstrated that can predict the system s dynamic behavior across a wide range of parametric settings.

Low Fidelity Imitation of Atypical Biological Kinematics in Autism Spectrum Disorders Is Modulated by Self-Generated Selective Attention

ERIC Educational Resources Information Center

Hayes, Spencer J.; Andrew, Matthew; Elliott, Digby; Gowen, Emma; Bennett, Simon J.

2016-01-01

We examined whether adults with autism had difficulty imitating atypical biological kinematics. To reduce the impact that higher-order processes have on imitation we used a non-human agent model to control social attention, and removed end-state target goals in half of the trials to minimise goal-directed attention. Findings showed that only…

Teaching Veterinary Anesthesia: A Survey-Based Evaluation of Two High-Fidelity Models and Live-Animal Experience for Undergraduate Veterinary Students.

PubMed

Musk, Gabrielle C; Collins, Teresa; Hosgood, Giselle

In veterinary medical education, reduction, replacement, and refinement (the three Rs) must be considered. Three clinical skills in anesthesia were identified as challenging to students: endotracheal intubation, intravenous catheterization, and drug dose calculations. The aims of this project were to evaluate students' perception of their level of confidence in performing these three clinical skills in veterinary anesthesia, to document the extent of students' previous experience in performing these three tasks, and to describe students' emotional states during this training. Veterinary students completed a series of four surveys over the period of their pre-clinical training to evaluate the usefulness of high-fidelity models for skill acquisition in endotracheal intubation and intravenous catheterization. In addition, practice and ongoing assessment in drug dose calculations were performed. The curriculum during this period of training progressed from lectures and non-animal training, to anesthesia of pigs undergoing surgery from which they did not recover, and finally to anesthesia of dogs and cats in a neutering clinic. The level of confidence for each of the three clinical skills increased over the study period. For each skill, the number of students with no confidence decreased to zero and the proportion of students with higher levels of confidence increased. The high-fidelity models for endotracheal intubation and intravenous catheterization used to complement the live-animal teaching were considered a useful adjunct to the teaching of clinical skills in veterinary anesthesia. With practice, students became more confident performing drug dose calculations.

A Comparative Study of High and Low Fidelity Fan Models for Turbofan Engine System Simulation

NASA Technical Reports Server (NTRS)

Reed, John A.; Afjeh, Abdollah A.

1991-01-01

In this paper, a heterogeneous propulsion system simulation method is presented. The method is based on the formulation of a cycle model of a gas turbine engine. The model includes the nonlinear characteristics of the engine components via use of empirical data. The potential to simulate the entire engine operation on a computer without the aid of data is demonstrated by numerically generating "performance maps" for a fan component using two flow models of varying fidelity. The suitability of the fan models were evaluated by comparing the computed performance with experimental data. A discussion of the potential benefits and/or difficulties in connecting simulations solutions of differing fidelity is given.

Multi-fidelity machine learning models for accurate bandgap predictions of solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab

Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned model that enables low-cost accurate predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelitymore » quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.« less

Multi-fidelity machine learning models for accurate bandgap predictions of solids

DOE PAGES

Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab

2016-12-28

Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned model that enables low-cost accurate predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelitymore » quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.« less

Fidelity and outcomes in six integrated dual disorders treatment programs.

PubMed

Chandler, Daniel W

2011-02-01

Fidelity scores and outcomes were measured in six outpatient programs in California which implemented Integrated Dual Disorders Treatment (IDDT). Outcomes were measured for 1 year in four sites and 2 years in two sites; fidelity was assessed at 6 month intervals. Three of the six sites achieved high fidelity (at least a 4 on a 5 point fidelity scale) and three moderate fidelity (at least a 3). Retention in treatment, mental health functioning, stage of substance abuse treatment, abstinence, and psychiatric hospitalization were measured. Outcomes for individual programs were generally positive but not consistent within programs or across programs. Using pooled data in a longitudinal regression model with random effects at person level and adjustment of standard errors for clustering by site, change over time was not statistically significant for the primary outcomes. Fidelity scores had limited association with positive outcomes.

Multifunctional Collaborative Modeling and Analysis Methods in Engineering Science

NASA Technical Reports Server (NTRS)

Ransom, Jonathan B.; Broduer, Steve (Technical Monitor)

2001-01-01

Engineers are challenged to produce better designs in less time and for less cost. Hence, to investigate novel and revolutionary design concepts, accurate, high-fidelity results must be assimilated rapidly into the design, analysis, and simulation process. This assimilation should consider diverse mathematical modeling and multi-discipline interactions necessitated by concepts exploiting advanced materials and structures. Integrated high-fidelity methods with diverse engineering applications provide the enabling technologies to assimilate these high-fidelity, multi-disciplinary results rapidly at an early stage in the design. These integrated methods must be multifunctional, collaborative, and applicable to the general field of engineering science and mechanics. Multifunctional methodologies and analysis procedures are formulated for interfacing diverse subdomain idealizations including multi-fidelity modeling methods and multi-discipline analysis methods. These methods, based on the method of weighted residuals, ensure accurate compatibility of primary and secondary variables across the subdomain interfaces. Methods are developed using diverse mathematical modeling (i.e., finite difference and finite element methods) and multi-fidelity modeling among the subdomains. Several benchmark scalar-field and vector-field problems in engineering science are presented with extensions to multidisciplinary problems. Results for all problems presented are in overall good agreement with the exact analytical solution or the reference numerical solution. Based on the results, the integrated modeling approach using the finite element method for multi-fidelity discretization among the subdomains is identified as most robust. The multiple-method approach is advantageous when interfacing diverse disciplines in which each of the method's strengths are utilized. The multifunctional methodology presented provides an effective mechanism by which domains with diverse idealizations are interfaced. This capability rapidly provides the high-fidelity results needed in the early design phase. Moreover, the capability is applicable to the general field of engineering science and mechanics. Hence, it provides a collaborative capability that accounts for interactions among engineering analysis methods.

Calculating Launch Vehicle Flight Performance Reserve

NASA Technical Reports Server (NTRS)

Hanson, John M.; Pinson, Robin M.; Beard, Bernard B.

2011-01-01

This paper addresses different methods for determining the amount of extra propellant (flight performance reserve or FPR) that is necessary to reach orbit with a high probability of success. One approach involves assuming that the various influential parameters are independent and that the result behaves as a Gaussian. Alternatively, probabilistic models may be used to determine the vehicle and environmental models that will be available (estimated) for a launch day go/no go decision. High-fidelity closed-loop Monte Carlo simulation determines the amount of propellant used with each random combination of parameters that are still unknown at the time of launch. Using the results of the Monte Carlo simulation, several methods were used to calculate the FPR. The final chosen solution involves determining distributions for the pertinent outputs and running a separate Monte Carlo simulation to obtain a best estimate of the required FPR. This result differs from the result obtained using the other methods sufficiently that the higher fidelity is warranted.

A multisite study of implementing supported employment in the Netherlands.

PubMed

van Erp, Nicole H J; Giesen, Femke B M; van Weeghel, Jaap; Kroon, Hans; Michon, Harry W C; Becker, Deborah; McHugo, Gregory J; Drake, Robert E

2007-11-01

This article reports on the implementation of the individual placement and support model of supported employment in four Dutch regions. The authors used structured site visits, employment data, and semistructured interviews to assess fidelity, employment outcomes, and facilitators of and barriers to successful implementation. At 24 months, the four sites reached a mean+/-SD fidelity score of 4.1+/-.3 (possible scores range from 1 to 5, with higher scores indicating closer adherence to the model). Of the 316 persons with mental illnesses, 57 (18%) obtained competitive jobs. Barriers to implementation included lack of organizational standards, loss of vocational staff, funding problems, insufficient time for program leaders, and inadequate cooperation between the involved organizations. Important facilitators were the skills and commitment of the vocational team members and the integration of vocational and mental health staff. To implement evidence-based supported employment in the Netherlands will require changes in financing, organizational structures, attitudes, cultural beliefs, and labor and disability regulations.

Within-subjects comparison of the HiRes and Fidelity120 speech processing strategies: speech perception and its relation to place-pitch sensitivity.

PubMed

Donaldson, Gail S; Dawson, Patricia K; Borden, Lamar Z

2011-01-01

Previous studies have confirmed that current steering can increase the number of discriminable pitches available to many cochlear implant (CI) users; however, the ability to perceive additional pitches has not been linked to improved speech perception. The primary goals of this study were to determine (1) whether adult CI users can achieve higher levels of spectral cue transmission with a speech processing strategy that implements current steering (Fidelity120) than with a predecessor strategy (HiRes) and, if so, (2) whether the magnitude of improvement can be predicted from individual differences in place-pitch sensitivity. A secondary goal was to determine whether Fidelity120 supports higher levels of speech recognition in noise than HiRes. A within-subjects repeated measures design evaluated speech perception performance with Fidelity120 relative to HiRes in 10 adult CI users. Subjects used the novel strategy (either HiRes or Fidelity120) for 8 wks during the main study; a subset of five subjects used Fidelity120 for three additional months after the main study. Speech perception was assessed for the spectral cues related to vowel F1 frequency, vowel F2 frequency, and consonant place of articulation; overall transmitted information for vowels and consonants; and sentence recognition in noise. Place-pitch sensitivity was measured for electrode pairs in the apical, middle, and basal regions of the implanted array using a psychophysical pitch-ranking task. With one exception, there was no effect of strategy (HiRes versus Fidelity120) on the speech measures tested, either during the main study (N = 10) or after extended use of Fidelity120 (N = 5). The exception was a small but significant advantage for HiRes over Fidelity120 for consonant perception during the main study. Examination of individual subjects' data revealed that 3 of 10 subjects demonstrated improved perception of one or more spectral cues with Fidelity120 relative to HiRes after 8 wks or longer experience with Fidelity120. Another three subjects exhibited initial decrements in spectral cue perception with Fidelity120 at the 8-wk time point; however, evidence from one subject suggested that such decrements may resolve with additional experience. Place-pitch thresholds were inversely related to improvements in vowel F2 frequency perception with Fidelity120 relative to HiRes. However, no relationship was observed between place-pitch thresholds and the other spectral measures (vowel F1 frequency or consonant place of articulation). Findings suggest that Fidelity120 supports small improvements in the perception of spectral speech cues in some Advanced Bionics CI users; however, many users show no clear benefit. Benefits are more likely to occur for vowel spectral cues (related to F1 and F2 frequency) than for consonant spectral cues (related to place of articulation). There was an inconsistent relationship between place-pitch sensitivity and improvements in spectral cue perception with Fidelity120 relative to HiRes. This may partly reflect the small number of sites at which place-pitch thresholds were measured. Contrary to some previous reports, there was no clear evidence that Fidelity120 supports improved sentence recognition in noise.

Economical Unsteady High-Fidelity Aerodynamics for Structural Optimization with a Flutter Constraint

NASA Technical Reports Server (NTRS)

Bartels, Robert E.; Stanford, Bret K.

2017-01-01

Structural optimization with a flutter constraint for a vehicle designed to fly in the transonic regime is a particularly difficult task. In this speed range, the flutter boundary is very sensitive to aerodynamic nonlinearities, typically requiring high-fidelity Navier-Stokes simulations. However, the repeated application of unsteady computational fluid dynamics to guide an aeroelastic optimization process is very computationally expensive. This expense has motivated the development of methods that incorporate aspects of the aerodynamic nonlinearity, classical tools of flutter analysis, and more recent methods of optimization. While it is possible to use doublet lattice method aerodynamics, this paper focuses on the use of an unsteady high-fidelity aerodynamic reduced order model combined with successive transformations that allows for an economical way of utilizing high-fidelity aerodynamics in the optimization process. This approach is applied to the common research model wing structural design. As might be expected, the high-fidelity aerodynamics produces a heavier wing than that optimized with doublet lattice aerodynamics. It is found that the optimized lower skin of the wing using high-fidelity aerodynamics differs significantly from that using doublet lattice aerodynamics.

Evolving Storage and Cyber Infrastructure at the NASA Center for Climate Simulation

NASA Technical Reports Server (NTRS)

Salmon, Ellen; Duffy, Daniel; Spear, Carrie; Sinno, Scott; Vaughan, Garrison; Bowen, Michael

2018-01-01

This talk will describe recent developments at the NASA Center for Climate Simulation, which is funded by NASAs Science Mission Directorate, and supports the specialized data storage and computational needs of weather, ocean, and climate researchers, as well as astrophysicists, heliophysicists, and planetary scientists. To meet requirements for higher-resolution, higher-fidelity simulations, the NCCS augments its High Performance Computing (HPC) and storage retrieval environment. As the petabytes of model and observational data grow, the NCCS is broadening data services offerings and deploying and expanding virtualization resources for high performance analytics.

Influence of imaging resolution on color fidelity in digital archiving.

PubMed

Zhang, Pengchang; Toque, Jay Arre; Ide-Ektessabi, Ari

2015-11-01

Color fidelity is of paramount importance in digital archiving. In this paper, the relationship between color fidelity and imaging resolution was explored by calculating the color difference of an IT8.7/2 color chart with a CIELAB color difference formula for scanning and simulation images. Microscopic spatial sampling was used in selecting the image pixels for the calculations to highlight the loss of color information. A ratio, called the relative imaging definition (RID), was defined to express the correlation between image resolution and color fidelity. The results show that in order for color differences to remain unrecognizable, the imaging resolution should be at least 10 times higher than the physical dimension of the smallest feature in the object being studied.

The Development of the Simulation Thinking Rubric

ERIC Educational Resources Information Center

Doolen, Jessica

2012-01-01

High fidelity simulation has become a widespread and costly learning strategy in nursing education because it can fill the gap left by a shortage of clinical sites. In addition, high fidelity simulation is an active learning strategy that is thought to increase higher order thinking such as clinical reasoning and judgment skills in nursing…

Further Validation of the Pathways Housing First Fidelity Scale.

PubMed

Goering, Paula; Veldhuizen, Scott; Nelson, Geoffrey B; Stefancic, Ana; Tsemberis, Sam; Adair, Carol E; Distasio, Jino; Aubry, Tim; Stergiopoulos, Vicky; Streiner, David L

2016-01-01

This study examined whether Housing First fidelity ratings correspond to program operation descriptions from administrative data and predict client outcomes. A multisite, randomized controlled trial (At Home/Chez Soi) in five Canadian cities included two assessments of 12 programs over two years. Outcomes for 1,158 clients were measured every six months. Associations between fidelity ratings and administrative data (Spearman correlations) and participant outcomes (mixed-effects modeling) were examined. Fidelity ratings were generally good (mean ± SD=136.6 ± 10.3 out of a possible range of 38-152; 87% of maximum value). Fidelity was significantly associated with three of four measures of program operation, with correlations between .55 and .60. Greater program fidelity was associated with improvement in housing stability, community functioning, and quality of life. Variation in program fidelity was associated with operations and outcomes, supporting scale validity and intervention effectiveness. These findings reinforced the value of using fidelity monitoring to conduct quality assurance and technical assistance activities.

Ensuring treatment fidelity in a multi-site behavioral intervention study: implementing NIH Behavior Change Consortium recommendations in the SMART trial.

PubMed

Robb, Sheri L; Burns, Debra S; Docherty, Sharron L; Haase, Joan E

2011-11-01

The Stories and Music for Adolescent/Young Adult Resilience during Transplant (SMART) study (R01NR008583; U10CA098543; U10CA095861) is an ongoing multi-site Children's Oncology Group randomized clinical trial testing the efficacy of a therapeutic music video intervention for adolescents/young adults (11-24 years of age) with cancer undergoing stem cell transplant. Treatment fidelity strategies from our trial are consistent with the National Institutes of Health (NIH) Behavior Change Consortium Treatment Fidelity Workgroup (BCC) recommendations and provide a successful working model for treatment fidelity implementation in a large, multi-site behavioral intervention study. In this paper, we summarize 20 specific treatment fidelity strategies used in the SMART trial and how these strategies correspond with NIH BCC recommendations in five specific areas: (1) study design, (2) training providers, (3) delivery of treatment, (4) receipt of treatment, and (5) enactment of treatment skills. Increased use and reporting of treatment fidelity procedures is essential in advancing the reliability and validity of behavioral intervention research. The SMART trial provides a strong model for the application of fidelity strategies to improve scientific findings and addresses the absence of published literature, illustrating the application of BCC recommendations in behavioral intervention studies. Copyright © 2010 John Wiley & Sons, Ltd.

A methodology for the assessment of manned flight simulator fidelity

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; Malsbury, Terry N.

1989-01-01

A relatively simple analytical methodology for assessing the fidelity of manned flight simulators for specific vehicles and tasks is offered. The methodology is based upon an application of a structural model of the human pilot, including motion cue effects. In particular, predicted pilot/vehicle dynamic characteristics are obtained with and without simulator limitations. A procedure for selecting model parameters can be implemented, given a probable pilot control strategy. In analyzing a pair of piloting tasks for which flight and simulation data are available, the methodology correctly predicted the existence of simulator fidelity problems. The methodology permitted the analytical evaluation of a change in simulator characteristics and indicated that a major source of the fidelity problems was a visual time delay in the simulation.

A Planar Quasi-Static Constraint Mode Tire Model

DTIC Science & Technology

2015-07-10

strikes a balance between simple tire models that lack the fidelity to make accurate chassis load predictions and computationally intensive models that...strikes a balance between heuristic tire models (such as a linear point-follower) that lack the fidelity to make accurate chassis load predictions...UNCLASSIFIED: Distribution Statement A. Cleared for public release A PLANAR QUASI-STATIC CONSTRAINT MODE TIRE MODEL Rui Maa John B. Ferris

An Analysis of the Educational Value of Low-Fidelity Anatomy Models as External Representations

ERIC Educational Resources Information Center

Chan, Lap Ki; Cheng, Maurice M. W.

2011-01-01

Although high-fidelity digital models of human anatomy based on actual cross-sectional images of the human body have been developed, reports on the use of physical models in anatomy teaching continue to appear. This article aims to examine the common features shared by these physical models and analyze their educational value based on the…

Attenuation of Foot-and-Mouth Disease Virus by Engineered Viral Polymerase Fidelity.

PubMed

Rai, Devendra K; Diaz-San Segundo, Fayna; Campagnola, Grace; Keith, Anna; Schafer, Elizabeth A; Kloc, Anna; de Los Santos, Teresa; Peersen, Olve; Rieder, Elizabeth

2017-08-01

Foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase (RdRp) (3D pol ) catalyzes viral RNA synthesis. Its characteristic low fidelity and absence of proofreading activity allow FMDV to rapidly mutate and adapt to dynamic environments. In this study, we used the structure of FMDV 3D pol in combination with previously reported results from similar picornaviral polymerases to design point mutations that would alter replication fidelity. In particular, we targeted Trp237 within conserved polymerase motif A because of the low reversion potential inherent in the single UGG codon. Using biochemical and genetic tools, we show that the replacement of tryptophan 237 with phenylalanine imparts higher fidelity, but replacements with isoleucine and leucine resulted in lower-fidelity phenotypes. Viruses containing these W237 substitutions show in vitro growth kinetics and plaque morphologies similar to those of the wild-type (WT) A 24 Cruzeiro strain in BHK cells, and both high- and low-fidelity variants retained fitness during coinfection with the wild-type virus. The higher-fidelity W237F (W237F HF ) mutant virus was more resistant to the mutagenic nucleoside analogs ribavirin and 5-fluorouracil than the WT virus, whereas the lower-fidelity W237I (W237I LF ) and W237L LF mutant viruses exhibited lower ribavirin resistance. Interestingly, the variant viruses showed heterogeneous and slightly delayed growth kinetics in primary porcine kidney cells, and they were significantly attenuated in mouse infection experiments. These data demonstrate, for a single virus, that either increased or decreased RdRp fidelity attenuates virus growth in animals, which is a desirable feature for the development of safer and genetically more stable vaccine candidates. IMPORTANCE Foot-and-mouth disease (FMD) is the most devastating disease affecting livestock worldwide. Here, using structural and biochemical analyses, we have identified FMDV 3D pol mutations that affect polymerase fidelity. Recombinant FMDVs containing substitutions at 3D pol tryptophan residue 237 were genetically stable and displayed plaque phenotypes and growth kinetics similar to those of the wild-type virus in cell culture. We further demonstrate that viruses harboring either a W237F HF substitution or W237I LF and W237L LF mutations were highly attenuated in animals. Our study shows that obtaining 3D pol fidelity variants by protein engineering based on polymerase structure and function could be exploited for the development of attenuated FMDV vaccine candidates that are safer and more stable than strains obtained by selective pressure via mutagenic nucleotides or adaptation approaches. Copyright © 2017 American Society for Microbiology.

Attenuation of Foot-and-Mouth Disease Virus by Engineered Viral Polymerase Fidelity

PubMed Central

Rai, Devendra K.; Diaz-San Segundo, Fayna; Campagnola, Grace; Keith, Anna; Schafer, Elizabeth A.; Kloc, Anna; de los Santos, Teresa; Peersen, Olve

2017-01-01

ABSTRACT Foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase (RdRp) (3Dpol) catalyzes viral RNA synthesis. Its characteristic low fidelity and absence of proofreading activity allow FMDV to rapidly mutate and adapt to dynamic environments. In this study, we used the structure of FMDV 3Dpol in combination with previously reported results from similar picornaviral polymerases to design point mutations that would alter replication fidelity. In particular, we targeted Trp237 within conserved polymerase motif A because of the low reversion potential inherent in the single UGG codon. Using biochemical and genetic tools, we show that the replacement of tryptophan 237 with phenylalanine imparts higher fidelity, but replacements with isoleucine and leucine resulted in lower-fidelity phenotypes. Viruses containing these W237 substitutions show in vitro growth kinetics and plaque morphologies similar to those of the wild-type (WT) A24 Cruzeiro strain in BHK cells, and both high- and low-fidelity variants retained fitness during coinfection with the wild-type virus. The higher-fidelity W237F (W237FHF) mutant virus was more resistant to the mutagenic nucleoside analogs ribavirin and 5-fluorouracil than the WT virus, whereas the lower-fidelity W237I (W237ILF) and W237LLF mutant viruses exhibited lower ribavirin resistance. Interestingly, the variant viruses showed heterogeneous and slightly delayed growth kinetics in primary porcine kidney cells, and they were significantly attenuated in mouse infection experiments. These data demonstrate, for a single virus, that either increased or decreased RdRp fidelity attenuates virus growth in animals, which is a desirable feature for the development of safer and genetically more stable vaccine candidates. IMPORTANCE Foot-and-mouth disease (FMD) is the most devastating disease affecting livestock worldwide. Here, using structural and biochemical analyses, we have identified FMDV 3Dpol mutations that affect polymerase fidelity. Recombinant FMDVs containing substitutions at 3Dpol tryptophan residue 237 were genetically stable and displayed plaque phenotypes and growth kinetics similar to those of the wild-type virus in cell culture. We further demonstrate that viruses harboring either a W237FHF substitution or W237ILF and W237LLF mutations were highly attenuated in animals. Our study shows that obtaining 3Dpol fidelity variants by protein engineering based on polymerase structure and function could be exploited for the development of attenuated FMDV vaccine candidates that are safer and more stable than strains obtained by selective pressure via mutagenic nucleotides or adaptation approaches. PMID:28515297

Development and validation of a Housing First fidelity survey.

PubMed

Gilmer, Todd P; Stefancic, Ana; Sklar, Marisa; Tsemberis, Sam

2013-09-01

Programs that use the Housing First model are being implemented throughout the United States and internationally. The authors describe the development and validation of a Housing First fidelity survey. A 46-item survey was developed to measure fidelity across five domains: housing process and structure, separation of housing and services, service philosophy, service array, and team structure. The survey was administered to staff and clients of 93 supported-housing programs in California. Exploratory and confirmatory factor analyses were used to identify the items and model structure that best fit the data. Sixteen items were retained in a two-factor model, one related to approach to housing, separation of housing and services, and service philosophy and one related to service array and team structure. Our survey mapped program practices by using a common metric that captured variation in fidelity to Housing First across a large-scale implementation of supported-housing programs.

High-fidelity data embedding for image annotation.

PubMed

He, Shan; Kirovski, Darko; Wu, Min

2009-02-01

High fidelity is a demanding requirement for data hiding, especially for images with artistic or medical value. This correspondence proposes a high-fidelity image watermarking for annotation with robustness to moderate distortion. To achieve the high fidelity of the embedded image, we introduce a visual perception model that aims at quantifying the local tolerance to noise for arbitrary imagery. Based on this model, we embed two kinds of watermarks: a pilot watermark that indicates the existence of the watermark and an information watermark that conveys a payload of several dozen bits. The objective is to embed 32 bits of metadata into a single image in such a way that it is robust to JPEG compression and cropping. We demonstrate the effectiveness of the visual model and the application of the proposed annotation technology using a database of challenging photographic and medical images that contain a large amount of smooth regions.

GIS Data Based Automatic High-Fidelity 3D Road Network Modeling

NASA Technical Reports Server (NTRS)

Wang, Jie; Shen, Yuzhong

2011-01-01

3D road models are widely used in many computer applications such as racing games and driving simulations_ However, almost all high-fidelity 3D road models were generated manually by professional artists at the expense of intensive labor. There are very few existing methods for automatically generating 3D high-fidelity road networks, especially those existing in the real world. This paper presents a novel approach thai can automatically produce 3D high-fidelity road network models from real 2D road GIS data that mainly contain road. centerline in formation. The proposed method first builds parametric representations of the road centerlines through segmentation and fitting . A basic set of civil engineering rules (e.g., cross slope, superelevation, grade) for road design are then selected in order to generate realistic road surfaces in compliance with these rules. While the proposed method applies to any types of roads, this paper mainly addresses automatic generation of complex traffic interchanges and intersections which are the most sophisticated elements in the road networks

Measuring Fidelity of Implementation--Methodological and Conceptual Issues and Challenges. CRESST Report 811

ERIC Educational Resources Information Center

Osmundson, Ellen; Herman, Joan; Ringstaff, Cathy; Dai, Yunyun; Timms, Mike

2012-01-01

A central challenge in efficacy studies centers on the issue of "fidelity of implementation," that is, the extent to which participants use the curriculum specified by curriculum developers. In this study, we describe and discuss a "fidelity of implementation" model using multiple methods and instruments to compare two versions of a science…

Applying the Five-Step Model of Fidelity Assessment to a Randomized Experiment of a High School STEM Intervention

ERIC Educational Resources Information Center

Kopp, Jason P.; Hulleman, Chris S.; Harackiewicz, Judith M.; Rozek, Chris

2012-01-01

Assessing fidelity of implementation is becoming increasingly important in education research, in particular as a tool for understanding variations in treatment effectiveness. Fidelity of implementation is defined as "the determination of how well an intervention is implemented in comparison with the original program design during an efficacy…

Enhancing Therapeutic Gains: Examination of Fidelity to the Model for the Intensive Mental Health Program

ERIC Educational Resources Information Center

Randall, Camille J.; Biggs, Bridget K.

2008-01-01

Given that the development of treatment fidelity assessment protocol is an integral but too frequently ignored aspect of clinical trials for psychological treatments, the Intensive Mental Health Program (IMHP) sought to build fidelity activities into training, program evaluation, and clinical recordkeeping from the outset of a 3 year study period.…

Relationship between Systems Coaching and Problem-Solving Implementation Fidelity in a Response-to-Intervention Model

ERIC Educational Resources Information Center

March, Amanda L.; Castillo, Jose M.; Batsche, George M.; Kincaid, Donald

2016-01-01

The literature on RTI has indicated that professional development and coaching are critical to facilitating problem-solving implementation with fidelity. This study examined the extent to which systems coaching related to the fidelity of problem-solving implementation in 31 schools from six districts. Schools participated in three years of a…

Diagnosing the impact of alternative calibration strategies on coupled hydrologic models

NASA Astrophysics Data System (ADS)

Smith, T. J.; Perera, C.; Corrigan, C.

2017-12-01

Hydrologic models represent a significant tool for understanding, predicting, and responding to the impacts of water on society and society on water resources and, as such, are used extensively in water resources planning and management. Given this important role, the validity and fidelity of hydrologic models is imperative. While extensive focus has been paid to improving hydrologic models through better process representation, better parameter estimation, and better uncertainty quantification, significant challenges remain. In this study, we explore a number of competing model calibration scenarios for simple, coupled snowmelt-runoff models to better understand the sensitivity / variability of parameterizations and its impact on model performance, robustness, fidelity, and transferability. Our analysis highlights the sensitivity of coupled snowmelt-runoff model parameterizations to alterations in calibration approach, underscores the concept of information content in hydrologic modeling, and provides insight into potential strategies for improving model robustness / fidelity.

A Comparison of Natural Language Processing Methods for Automated Coding of Motivational Interviewing.

PubMed

Tanana, Michael; Hallgren, Kevin A; Imel, Zac E; Atkins, David C; Srikumar, Vivek

2016-06-01

Motivational interviewing (MI) is an efficacious treatment for substance use disorders and other problem behaviors. Studies on MI fidelity and mechanisms of change typically use human raters to code therapy sessions, which requires considerable time, training, and financial costs. Natural language processing techniques have recently been utilized for coding MI sessions using machine learning techniques, rather than human coders, and preliminary results have suggested these methods hold promise. The current study extends this previous work by introducing two natural language processing models for automatically coding MI sessions via computer. The two models differ in the way they semantically represent session content, utilizing either 1) simple discrete sentence features (DSF model) and 2) more complex recursive neural networks (RNN model). Utterance- and session-level predictions from these models were compared to ratings provided by human coders using a large sample of MI sessions (N=341 sessions; 78,977 clinician and client talk turns) from 6 MI studies. Results show that the DSF model generally had slightly better performance compared to the RNN model. The DSF model had "good" or higher utterance-level agreement with human coders (Cohen's kappa>0.60) for open and closed questions, affirm, giving information, and follow/neutral (all therapist codes); considerably higher agreement was obtained for session-level indices, and many estimates were competitive with human-to-human agreement. However, there was poor agreement for client change talk, client sustain talk, and therapist MI-inconsistent behaviors. Natural language processing methods provide accurate representations of human derived behavioral codes and could offer substantial improvements to the efficiency and scale in which MI mechanisms of change research and fidelity monitoring are conducted. Copyright © 2016 Elsevier Inc. All rights reserved.

Using mixed methods to assess fidelity of delivery and its influencing factors in a complex self-management intervention for people with osteoarthritis and low back pain.

PubMed

Toomey, Elaine; Matthews, James; Hurley, Deirdre A

2017-08-04

Despite an increasing awareness of the importance of fidelity of delivery within complex behaviour change interventions, it is often poorly assessed. This mixed methods study aimed to establish the fidelity of delivery of a complex self-management intervention and explore the reasons for these findings using a convergent/triangulation design. Feasibility trial of the Self-management of Osteoarthritis and Low back pain through Activity and Skills (SOLAS) intervention (ISRCTN49875385), delivered in primary care physiotherapy. 60 SOLAS sessions were delivered across seven sites by nine physiotherapists. Fidelity of delivery of prespecified intervention components was evaluated using (1) audio-recordings (n=60), direct observations (n=24) and self-report checklists (n=60) and (2) individual interviews with physiotherapists (n=9). Quantitatively, fidelity scores were calculated using percentage means and SD of components delivered. Associations between fidelity scores and physiotherapist variables were analysed using Spearman's correlations. Interviews were analysed using thematic analysis to explore potential reasons for fidelity scores. Integration of quantitative and qualitative data occurred at an interpretation level using triangulation. Quantitatively, fidelity scores were high for all assessment methods; with self-report (92.7%) consistently higher than direct observations (82.7%) or audio-recordings (81.7%). There was significant variation between physiotherapists' individual scores (69.8% - 100%). Both qualitative and quantitative data (from physiotherapist variables) found that physiotherapists' knowledge (Spearman's association at p=0.003) and previous experience (p=0.008) were factors that influenced their fidelity. The qualitative data also postulated participant-level (eg, individual needs) and programme-level factors (eg, resources) as additional elements that influenced fidelity. The intervention was delivered with high fidelity. This study contributes to the limited evidence regarding fidelity assessment methods within complex behaviour change interventions. The findings suggest a combination of quantitative methods is suitable for the assessment of fidelity of delivery. A mixed methods approach provided a more insightful understanding of fidelity and its influencing factors. ISRCTN49875385; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Site fidelity, territory fidelity, and natal philopatry in Willow Flycatchers (Empidonax traillii)

USGS Publications Warehouse

Sedgwick, James A.

2004-01-01

I investigated the causes and consequences of adult breeding-site fidelity, territory fidelity, and natal philopatry in Willow Flycatchers (Empidonax traillii) in southeastern Oregon over a 10-year period, testing the general hypothesis that fidelity and dispersal distances are influenced by previous breeding performance. Willow Flycatchers adhered to the generally observed tendencies of passerine birds for low natal philopatry and high breedingsite fidelity. Site fidelity (return to the study area) of adult males (52.0%) and females (51.3%), and median dispersal distances between seasons (16 m vs. 19 m) were similar. Previous breeding performance and residency (age-experience), but not study-site quality, explained site fidelity in females. Site fidelity of females rearing 4–5 young (64.4%) exceeded that of unsuccessful females (40.0%), breeding dispersal was less (successful: 15 m; unsuccessful: 33 m), and novice residents were more site-faithful than former residents. Probability of site fidelity was higher for previously successful females (odds ratio = 4.76), those with greater seasonal fecundity (odds ratio = 1.58), novice residents (odds ratio = 1.41), and unparasitized females (odds ratio = 2.76). Male site fidelity was not related to residency, site quality, or previous breeding performance. Territory fidelity (return to the previous territory) in females was best explained by previous breeding performance, but not by site quality or residency. Previously successful females were more likely to return to their territory of the previous season than either unsuccessful (odds ratio = 14.35) or parasitized birds (odds ratio = 6.38). Male territory fidelity was not related to residency, site quality, or previous breeding performance. Natal philopatry was low (7.8%) and similar for males and females. Site quality appeared to influence philopatry, given that no birds reared at a low-quality study site returned there to breed, and birds reared there dispersed farther than birds reared at two other study sites. My results partially support the hypothesis that site fidelity is an adaptive response: (1) previously successful females that switched territories underperformed those that did not switch (P = 0.01); and (2) previously unsuccessful females that switched territories outperformed those that did not switch, but not significantly (P = 0.22).

Using mixed methods to assess fidelity of delivery and its influencing factors in a complex self-management intervention for people with osteoarthritis and low back pain

PubMed Central

Toomey, Elaine; Matthews, James; Hurley, Deirdre A

2017-01-01

Objectives and design Despite an increasing awareness of the importance of fidelity of delivery within complex behaviour change interventions, it is often poorly assessed. This mixed methods study aimed to establish the fidelity of delivery of a complex self-management intervention and explore the reasons for these findings using a convergent/triangulation design. Setting Feasibility trial of the Self-management of Osteoarthritis and Low back pain through Activity and Skills (SOLAS) intervention (ISRCTN49875385), delivered in primary care physiotherapy. Methods and outcomes 60 SOLAS sessions were delivered across seven sites by nine physiotherapists. Fidelity of delivery of prespecified intervention components was evaluated using (1) audio-recordings (n=60), direct observations (n=24) and self-report checklists (n=60) and (2) individual interviews with physiotherapists (n=9). Quantitatively, fidelity scores were calculated using percentage means and SD of components delivered. Associations between fidelity scores and physiotherapist variables were analysed using Spearman’s correlations. Interviews were analysed using thematic analysis to explore potential reasons for fidelity scores. Integration of quantitative and qualitative data occurred at an interpretation level using triangulation. Results Quantitatively, fidelity scores were high for all assessment methods; with self-report (92.7%) consistently higher than direct observations (82.7%) or audio-recordings (81.7%). There was significant variation between physiotherapists’ individual scores (69.8% - 100%). Both qualitative and quantitative data (from physiotherapist variables) found that physiotherapists’ knowledge (Spearman’s association at p=0.003) and previous experience (p=0.008) were factors that influenced their fidelity. The qualitative data also postulated participant-level (eg, individual needs) and programme-level factors (eg, resources) as additional elements that influenced fidelity. Conclusion The intervention was delivered with high fidelity. This study contributes to the limited evidence regarding fidelity assessment methods within complex behaviour change interventions. The findings suggest a combination of quantitative methods is suitable for the assessment of fidelity of delivery. A mixed methods approach provided a more insightful understanding of fidelity and its influencing factors. Trial registration number ISRCTN49875385; Pre-results. PMID:28780544

Instrumental and Conventional Interpretations of Behavior Are Associated with Distinct Outcomes in Early Childhood

ERIC Educational Resources Information Center

Clegg, Jennifer M.; Legare, Cristine H.

2016-01-01

Four tasks (N = 191, 3- to 6-year-olds) examined the effect of instrumental versus conventional language cues on children's imitative fidelity of a necklace-making activity, their memory and transmission of the activity, and their perceptions of functional fixedness. Children in the conventional condition imitated with higher fidelity, transmitted…

Within-subjects comparison of the HiRes and Fidelity120 speech processing strategies: Speech perception and its relation to place-pitch sensitivity

PubMed Central

Donaldson, Gail S.; Dawson, Patricia K.; Borden, Lamar Z.

2010-01-01

Objectives Previous studies have confirmed that current steering can increase the number of discriminable pitches available to many CI users; however, the ability to perceive additional pitches has not been linked to improved speech perception. The primary goals of this study were to determine (1) whether adult CI users can achieve higher levels of spectral-cue transmission with a speech processing strategy that implements current steering (Fidelity120) than with a predecessor strategy (HiRes) and, if so, (2) whether the magnitude of improvement can be predicted from individual differences in place-pitch sensitivity. A secondary goal was to determine whether Fidelity120 supports higher levels of speech recognition in noise than HiRes. Design A within-subjects repeated measures design evaluated speech perception performance with Fidelity120 relative to HiRes in 10 adult CI users. Subjects used the novel strategy (either HiRes or Fidelity120) for 8 weeks during the main study; a subset of five subjects used Fidelity120 for 3 additional months following the main study. Speech perception was assessed for the spectral cues related to vowel F1 frequency (Vow F1), vowel F2 frequency (Vow F2) and consonant place of articulation (Con PLC); overall transmitted information for vowels (Vow STIM) and consonants (Con STIM); and sentence recognition in noise. Place-pitch sensitivity was measured for electrode pairs in the apical, middle and basal regions of the implanted array using a psychophysical pitch-ranking task. Results With one exception, there was no effect of strategy (HiRes vs. Fidelity120) on the speech measures tested, either during the main study (n=10) or after extended use of Fidelity120 (n=5). The exception was a small but significant advantage for HiRes over Fidelity120 for the Con STIM measure during the main study. Examination of individual subjects' data revealed that 3 of 10 subjects demonstrated improved perception of one or more spectral cues with Fidelity120 relative to HiRes after 8 weeks or longer experience with Fidelity120. Another 3 subjects exhibited initial decrements in spectral cue perception with Fidelity120 at the 8 week time point; however, evidence from one subject suggested that such decrements may resolve with additional experience. Place-pitch thresholds were inversely related to improvements in Vow F2 perception with Fidelity120 relative to HiRes. However, no relationship was observed between place-pitch thresholds and the other spectral measures (Vow F1 or Con PLC). Conclusions Findings suggest that Fidelity120 supports small improvements in the perception of spectral speech cues in some Advanced Bionics CI users; however, many users show no clear benefit. Benefits are more likely to occur for vowel spectral cues (related to F1 and F2 frequency) than for consonant spectral cues (related to place of articulation). There was an inconsistent relationship between place-pitch sensitivity and improvements in spectral cue perception with Fidelity120 relative to HiRes. This may partly reflect the small number of sites at which place-pitch thresholds were measured. Contrary to some previous reports, there was no clear evidence that Fidelity120 supports improved sentence recognition in noise. PMID:21084987

An Integrated Approach to Modeling Solar Electric Propulsion Vehicles During Long Duration, Near-Earth Orbit Transfers

NASA Technical Reports Server (NTRS)

Smith, David A.; Hojnicki, Jeffrey S.; Sjauw, Waldy K.

2014-01-01

Recent NASA interest in utilizing solar electronic propulsion (SEP) technology to transfer payloads, e.g. from low-Earth orbit (LEO) to higher energy geostationary-Earth orbit (GEO) or to Earth escape, has necessitated the development of high fidelity SEP vehicle models and simulations. These models and simulations need to be capable of capturing vehicle dynamics and sub-system interactions experienced during the transfer trajectories which are typically accomplished with continuous-burn (potentially interrupted by solar eclipse), long duration "spiral out" maneuvers taking several months or more to complete. This paper presents details of an integrated simulation approach achieved by combining a high fidelity vehicle simulation code with a detailed solar array model. The combined simulation tool gives researchers the functionality to study the integrated effects of various vehicle sub-systems (e.g. vehicle guidance, navigation and control (GN&C), electric propulsion system (EP)) with time varying power production. Results from a simulation model of a vehicle with a 50 kW class SEP system using the integrated tool are presented and compared to the results from another simulation model employing a 50 kW end-of-life (EOL) fixed power level assumption. These models simulate a vehicle under three degree of freedom dynamics (i.e. translational dynamics only) and include the effects of a targeting guidance algorithm (providing a "near optimal" transfer) during a LEO to near Earth escape (C (sub 3) = -2.0 km (sup 2) / sec (sup -2) spiral trajectory. The presented results include the impact of the fully integrated, time-varying solar array model (e.g. cumulative array degradation from traversing the Van Allen belts, impact of solar eclipses on the vehicle and the related temperature responses in the solar arrays due to operating in the Earth's thermal environment, high fidelity array power module, etc.); these are used to assess the impact on vehicle performance (i.e. propellant consumption) and transit times.

Machine Learning for Discriminating Quantum Measurement Trajectories and Improving Readout.

PubMed

Magesan, Easwar; Gambetta, Jay M; Córcoles, A D; Chow, Jerry M

2015-05-22

Current methods for classifying measurement trajectories in superconducting qubit systems produce fidelities systematically lower than those predicted by experimental parameters. Here, we place current classification methods within the framework of machine learning (ML) algorithms and improve on them by investigating more sophisticated ML approaches. We find that nonlinear algorithms and clustering methods produce significantly higher assignment fidelities that help close the gap to the fidelity possible under ideal noise conditions. Clustering methods group trajectories into natural subsets within the data, which allows for the diagnosis of systematic errors. We find large clusters in the data associated with T1 processes and show these are the main source of discrepancy between our experimental and ideal fidelities. These error diagnosis techniques help provide a path forward to improve qubit measurements.

Site fidelity of the declining amphibian Rana sierrae (Sierra Nevada yellow-legged frog)

Treesearch

Kathleen Matthews; Haiganoush Preisler

2010-01-01

From 1997 to 2006, we used mark–recapture models to estimate the site fidelity of 1250 Sierra Nevada yellow-legged frogs (Rana sierrae) in Kings Canyon National Park, California, USA, during their three main activity periods of overwintering, breeding, and feeding. To quantify site fidelity, the tendency to return to and reuse previously occupied...

NASA Ames Sonic Boom Testing

NASA Technical Reports Server (NTRS)

Durston, Donald A.; Kmak, Francis J.

2009-01-01

Multiple sonic boom wind tunnel models were tested in the NASA Ames Research Center 9-by 7-Foot Supersonic Wind Tunnel to reestablish related test techniques in this facility. The goal of the testing was to acquire higher fidelity sonic boom signatures with instrumentation that is significantly more sensitive than that used during previous wind tunnel entries and to compare old and new data from established models. Another objective was to perform tunnel-to-tunnel comparisons of data from a Gulfstream sonic boom model tested at the NASA Langley Research Center 4-foot by 4-foot Unitary Plan Wind Tunnel.

Finite grid instability and spectral fidelity of the electrostatic Particle-In-Cell algorithm

DOE PAGES

Huang, C. -K.; Zeng, Y.; Wang, Y.; ...

2016-10-01

The origin of the Finite Grid Instability (FGI) is studied by resolving the dynamics in the 1D electrostatic Particle-In-Cell (PIC) model in the spectral domain at the single particle level and at the collective motion level. The spectral fidelity of the PIC model is contrasted with the underlying physical system or the gridless model. The systematic spectral phase and amplitude errors from the charge deposition and field interpolation are quantified for common particle shapes used in the PIC models. Lastly, it is shown through such analysis and in simulations that the lack of spectral fidelity relative to the physical systemmore » due to the existence of aliased spatial modes is the major cause of the FGI in the PIC model.« less

Finite grid instability and spectral fidelity of the electrostatic Particle-In-Cell algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, C. -K.; Zeng, Y.; Wang, Y.

The origin of the Finite Grid Instability (FGI) is studied by resolving the dynamics in the 1D electrostatic Particle-In-Cell (PIC) model in the spectral domain at the single particle level and at the collective motion level. The spectral fidelity of the PIC model is contrasted with the underlying physical system or the gridless model. The systematic spectral phase and amplitude errors from the charge deposition and field interpolation are quantified for common particle shapes used in the PIC models. Lastly, it is shown through such analysis and in simulations that the lack of spectral fidelity relative to the physical systemmore » due to the existence of aliased spatial modes is the major cause of the FGI in the PIC model.« less

Orbit Stability of OSIRIS-REx in the Vicinity of Bennu Using a High-Fidelity Solar Radiation Model

NASA Technical Reports Server (NTRS)

Williams, Trevor W.; Hughes, Kyle M.; Mashiku, Alinda K.; Longuski, James M.

2015-01-01

Solar radiation pressure is one of the largest perturbing forces on the OSIRISRex trajectory as it orbits the asteroid Bennu. In this work, we investigate how forces due to solar radiation perturb the OSIRIS-REx trajectory in a high-fidelity model. The model accounts for Bennu's non-spherical gravity field, third-body gravity forces from the Sun and Jupiter, as well as solar radiation forces acting on a simplified spacecraft model. Such high-fidelity simulations indicate significant solar radiation pressure perturbations from the nominal orbit. Modifications to the initial design of the nominal orbit are found using a variation of parameters approach that reduce the perturbation in eccentricity by a factor of one-half.

Multi-level of Fidelity Multi-Disciplinary Design Optimization of Small, Solid-Propellant Launch Vehicles

NASA Astrophysics Data System (ADS)

Roshanian, Jafar; Jodei, Jahangir; Mirshams, Mehran; Ebrahimi, Reza; Mirzaee, Masood

A new automated multi-level of fidelity Multi-Disciplinary Design Optimization (MDO) methodology has been developed at the MDO Laboratory of K.N. Toosi University of Technology. This paper explains a new design approach by formulation of developed disciplinary modules. A conceptual design for a small, solid-propellant launch vehicle was considered at two levels of fidelity structure. Low and medium level of fidelity disciplinary codes were developed and linked. Appropriate design and analysis codes were defined according to their effect on the conceptual design process. Simultaneous optimization of the launch vehicle was performed at the discipline level and system level. Propulsion, aerodynamics, structure and trajectory disciplinary codes were used. To reach the minimum launch weight, the Low LoF code first searches the whole design space to achieve the mission requirements. Then the medium LoF code receives the output of the low LoF and gives a value near the optimum launch weight with more details and higher fidelity.

A High-Order, Linear Time-Invariant Model for Application to Higher Harmonic Control and Flight Control System Interaction

NASA Technical Reports Server (NTRS)

Cheng, Rendy P.; Tischler, Mark B.; Celi, Roberto

2006-01-01

This research describes a new methodology for the extraction of a high-order, linear time invariant model, which allows the periodicity of the helicopter response to be accurately captured. This model provides the needed level of dynamic fidelity to permit an analysis and optimization of the AFCS and HHC algorithms. The key results of this study indicate that the closed-loop HHC system has little influence on the AFCS or on the vehicle handling qualities, which indicates that the AFCS does not need modification to work with the HHC system. However, the results show that the vibration response to maneuvers must be considered during the HHC design process, and this leads to much higher required HHC loop crossover frequencies. This research also demonstrates that the transient vibration responses during maneuvers can be reduced by optimizing the closed-loop higher harmonic control algorithm using conventional control system analyses.

A randomized controlled study of manikin simulator fidelity on neonatal resuscitation program learning outcomes.

PubMed

Curran, Vernon; Fleet, Lisa; White, Susan; Bessell, Clare; Deshpandey, Akhil; Drover, Anne; Hayward, Mark; Valcour, James

2015-03-01

The neonatal resuscitation program (NRP) has been developed to educate physicians and other health care providers about newborn resuscitation and has been shown to improve neonatal resuscitation skills. Simulation-based training is recommended as an effective modality for instructing neonatal resuscitation and both low and high-fidelity manikin simulators are used. There is limited research that has compared the effect of low and high-fidelity manikin simulators for NRP learning outcomes, and more specifically on teamwork performance and confidence. The purpose of this study was to examine the effect of using low versus high-fidelity manikin simulators in NRP instruction. A randomized posttest-only control group study design was conducted. Third year undergraduate medical students participated in NRP instruction and were assigned to an experimental group (high-fidelity manikin simulator) or control group (low-fidelity manikin simulator). Integrated skills station (megacode) performance, participant satisfaction, confidence and teamwork behaviour scores were compared between the study groups. Participants in the high-fidelity manikin simulator instructional group reported significantly higher total scores in overall satisfaction (p = 0.001) and confidence (p = 0.001). There were no significant differences in teamwork behaviour scores, as observed by two independent raters, nor differences on mandatory integrated skills station performance items at the p < 0.05 level. Medical students' reported greater satisfaction and confidence with high-fidelity manikin simulators, but did not demonstrate overall significantly improved teamwork or integrated skills station performance. Low and high-fidelity manikin simulators facilitate similar levels of objectively measured NRP outcomes for integrated skills station and teamwork performance.

End of Life Disposal for Three Libration Point Missions through Manipulation of the Jacobi Constant and Zero Velocity Curves

NASA Technical Reports Server (NTRS)

Peterson, Jeremy D.; Brown, Jonathan M.

2015-01-01

The aim of this investigation is to determine the feasibility of mission disposal by inserting the spacecraft into a heliocentric orbit along the unstable manifold and then manipulating the Jacobi constant to prevent the spacecraft from returning to the Earth-Moon system. This investigation focuses around L1 orbits representative of ACE, WIND, and SOHO. It will model the impulsive delta-V necessary to close the zero velocity curves after escape through the L1 gateway in the circular restricted three body model and also include full ephemeris force models and higher fidelity finite maneuver models for the three spacecraft.

Modeling Contamination Migration on the Chandra X-ray Observatory - II

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexey A.; Tennant, Allyn F.

2013-01-01

During its first 14 years of operation, the cold (about -60C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon temperature data, and a refined model of the molecular transport.

A Supervisor-Targeted Implementation Approach to Promote System Change: The R3 Model.

PubMed

Saldana, Lisa; Chamberlain, Patricia; Chapman, Jason

2016-11-01

Opportunities to evaluate strategies to create system-wide change in the child welfare system (CWS) and the resulting public health impact are rare. Leveraging a real-world, system-initiated effort to infuse the use of evidence-based principles throughout a CWS workforce, a pilot of the R 3 model and supervisor-targeted implementation approach is described. The development of R 3 and its associated fidelity monitoring was a collaboration between the CWS and model developers. Outcomes demonstrate implementation feasibility, strong fidelity scale measurement properties, improved supervisor fidelity over time, and the acceptability and perception of positive change by agency leadership. The value of system-initiated collaborations is discussed.

Value-based payment in implementing evidence-based care: the Mental Health Integration Program in Washington state.

PubMed

Bao, Yuhua; McGuire, Thomas G; Chan, Ya-Fen; Eggman, Ashley A; Ryan, Andrew M; Bruce, Martha L; Pincus, Harold Alan; Hafer, Erin; Unützer, Jürgen

2017-01-01

To assess the role of value-based payment (VBP) in improving fidelity and patient outcomes in community implementation of an evidence-based mental health intervention, the Collaborative Care Model (CCM). Retrospective study based on a natural experiment. We used the clinical tracking data of 1806 adult patients enrolled in a large implementation of the CCM in community health clinics in Washington state. VBP was initiated in year 2 of the program, creating a natural experiment. We compared implementation fidelity (measured by 3 process-of-care elements of the CCM) between patient-months exposed to VBP and patient-months not exposed to VBP. A series of regressions were estimated to check robustness of findings. We estimated a Cox proportional hazard model to assess the effect of VBP on time to achieving clinically significant improvement in depression (measured based on changes in depression symptom scores over time). Estimated marginal effects of VBP on fidelity ranged from 9% to 30% of the level of fidelity had there been no exposure to VBP (P <.05 for every fidelity measure). Improvement in fidelity in response to VBP was greater among providers with a larger patient panel and among providers with a lower level of fidelity at baseline. Exposure to VBP was associated with an adjusted hazard ratio of 1.45 (95% confidence interval, 1.04-2.03) for achieving clinically significant improvement in depression. VBP improved fidelity to key elements of the CCM, both directly incentivized and not explicitly incentivized by the VBP, and improved patient depression outcomes.

An Experimental Study of Procedures to Enhance Ratings of Fidelity to an Evidence-Based Family Intervention.

PubMed

Smith, Justin D; Dishion, Thomas J; Brown, Kimbree; Ramos, Karina; Knoble, Naomi B; Shaw, Daniel S; Wilson, Melvin N

2016-01-01

The valid and reliable assessment of fidelity is critical at all stages of intervention research and is particularly germane to interpreting the results of efficacy and implementation trials. Ratings of protocol adherence typically are reliable, but ratings of therapist competence are plagued by low reliability. Because family context and case conceptualization guide the therapist's delivery of interventions, the reliability of fidelity ratings might be improved if the coder is privy to client context in the form of an ecological assessment. We conducted a randomized experiment to test this hypothesis. A subsample of 46 families with 5-year-old children from a multisite randomized trial who participated in the feedback session of the Family Check-Up (FCU) intervention were selected. We randomly assigned FCU feedback sessions to be rated for fidelity to the protocol using the COACH rating system either after the coder reviewed the results of a recent ecological assessment or had not. Inter-rater reliability estimates of fidelity ratings were meaningfully higher for the assessment information condition compared to the no-information condition. Importantly, the reliability of the COACH mean score was found to be statistically significantly higher in the information condition. These findings suggest that the reliability of observational ratings of fidelity, particularly when the competence or quality of delivery is considered, could be improved by providing assessment data to the coders. Our findings might be most applicable to assessment-driven interventions, where assessment data explicitly guides therapist's selection of intervention strategies tailored to the family's context and needs, but they could also apply to other intervention programs and observational coding of context-dependent therapy processes, such as the working alliance.

An Experimental Study of Procedures to Enhance Ratings of Fidelity to an Evidence-Based Family Intervention

PubMed Central

Smith, Justin D.; Dishion, Thomas J.; Brown, Kimbree; Ramos, Karina; Knoble, Naomi B.; Shaw, Daniel S.; Wilson, Melvin N.

2015-01-01

The valid and reliable assessment of fidelity is critical at all stages of intervention research and is particularly germane to interpreting the results of efficacy and implementation trials. Ratings of protocol adherence typically are reliable, but ratings of therapist competence are plagued by low reliability. Because family context and case conceptualization guide the therapist's delivery of interventions, the reliability of fidelity ratings might be improved if the coder is privy to client context in the form of an ecological assessment. We conducted a randomized experiment to test this hypothesis. A subsample of 46 families with 5-year-old children from a multisite randomized trial who participated in the feedback session of the Family Check-Up (FCU) intervention were selected. We randomly assigned FCU feedback sessions to be rated for fidelity to the protocol using the COACH rating system either after the coder reviewed the results of a recent ecological assessment or had not. Inter-rater reliability estimates of fidelity ratings were meaningfully higher for the assessment information condition compared to the no-information condition. Importantly, the reliability of the COACH mean score was found to be statistically significantly higher in the information condition. These findings suggest that the reliability of observational ratings of fidelity, particularly when the competence or quality of delivery is considered, could be improved by providing assessment data to the coders. Our findings might be most applicable to assessment-driven interventions, where assessment data explicitly guides therapist's selection of intervention strategies tailored to the family's context and needs, but they could also apply to other intervention programs and observational coding of context-dependent therapy processes, such as the working alliance. PMID:26271300

Design and Analysis Tool for External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2012-01-01

A computational tool named SUPIN has been developed to design and analyze external-compression supersonic inlets for aircraft at cruise speeds from Mach 1.6 to 2.0. The inlet types available include the axisymmetric outward-turning, two-dimensional single-duct, two-dimensional bifurcated-duct, and streamline-traced Busemann inlets. The aerodynamic performance is characterized by the flow rates, total pressure recovery, and drag. The inlet flowfield is divided into parts to provide a framework for the geometry and aerodynamic modeling and the parts are defined in terms of geometric factors. The low-fidelity aerodynamic analysis and design methods are based on analytic, empirical, and numerical methods which provide for quick analysis. SUPIN provides inlet geometry in the form of coordinates and surface grids useable by grid generation methods for higher-fidelity computational fluid dynamics (CFD) analysis. SUPIN is demonstrated through a series of design studies and CFD analyses were performed to verify some of the analysis results.

Mixed-state fidelity susceptibility through iterated commutator series expansion

NASA Astrophysics Data System (ADS)

Tonchev, N. S.

2014-11-01

We present a perturbative approach to the problem of computation of mixed-state fidelity susceptibility (MFS) for thermal states. The mathematical techniques used provide an analytical expression for the MFS as a formal expansion in terms of the thermodynamic mean values of successively higher commutators of the Hamiltonian with the operator involved through the control parameter. That expression is naturally divided into two parts: the usual isothermal susceptibility and a constituent in the form of an infinite series of thermodynamic mean values which encodes the noncommutativity in the problem. If the symmetry properties of the Hamiltonian are given in terms of the generators of some (finite-dimensional) algebra, the obtained expansion may be evaluated in a closed form. This issue is tested on several popular models, for which it is shown that the calculations are much simpler if they are based on the properties from the representation theory of the Heisenberg or SU(1, 1) Lie algebra.

Ground-state fidelity and bipartite entanglement in the Bose-Hubbard model.

PubMed

Buonsante, P; Vezzani, A

2007-03-16

We analyze the quantum phase transition in the Bose-Hubbard model borrowing two tools from quantum-information theory, i.e., the ground-state fidelity and entanglement measures. We consider systems at unitary filling comprising up to 50 sites and show for the first time that a finite-size scaling analysis of these quantities provides excellent estimates for the quantum critical point. We conclude that fidelity is particularly suited for revealing a quantum phase transition and pinning down the critical point thereof, while the success of entanglement measures depends on the mechanisms governing the transition.

Administrator Strategies that Support High Fidelity Implementation of the Pyramid Model for Promoting Social-Emotional Competence & Addressing Challenging Behavior

ERIC Educational Resources Information Center

Mincic, Melissa; Smith, Barbara J.; Strain, Phil

2009-01-01

Implementing the Pyramid Model with fidelity and achieving positive outcomes for children and their families requires that administrators understand their roles in the implementation process. Every administrative decision impacts program quality and sustainability. This Policy Brief underscores the importance of facilitative administrative…

Multi-fidelity Gaussian process regression for prediction of random fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parussini, L.; Venturi, D., E-mail: venturi@ucsc.edu; Perdikaris, P.

We propose a new multi-fidelity Gaussian process regression (GPR) approach for prediction of random fields based on observations of surrogate models or hierarchies of surrogate models. Our method builds upon recent work on recursive Bayesian techniques, in particular recursive co-kriging, and extends it to vector-valued fields and various types of covariances, including separable and non-separable ones. The framework we propose is general and can be used to perform uncertainty propagation and quantification in model-based simulations, multi-fidelity data fusion, and surrogate-based optimization. We demonstrate the effectiveness of the proposed recursive GPR techniques through various examples. Specifically, we study the stochastic Burgersmore » equation and the stochastic Oberbeck–Boussinesq equations describing natural convection within a square enclosure. In both cases we find that the standard deviation of the Gaussian predictors as well as the absolute errors relative to benchmark stochastic solutions are very small, suggesting that the proposed multi-fidelity GPR approaches can yield highly accurate results.« less

An empirical study of multidimensional fidelity of COMPASS consultation.

PubMed

Wong, Venus; Ruble, Lisa A; McGrew, John H; Yu, Yue

2018-06-01

Consultation is essential to the daily practice of school psychologists (National Association of School Psychologist, 2010). Successful consultation requires fidelity at both the consultant (implementation) and consultee (intervention) levels. We applied a multidimensional, multilevel conception of fidelity (Dunst, Trivette, & Raab, 2013) to a consultative intervention called the Collaborative Model for Promoting Competence and Success (COMPASS) for students with autism. The study provided 3 main findings. First, multidimensional, multilevel fidelity is a stable construct and increases over time with consultation support. Second, mediation analyses revealed that implementation-level fidelity components had distant, indirect effects on student Individualized Education Program (IEP) outcomes. Third, 3 fidelity components correlated with IEP outcomes: teacher coaching responsiveness at the implementation level, and teacher quality of delivery and student responsiveness at the intervention levels. Implications and future directions are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Crystal plasticity modeling of β phase deformation in Ti-6Al-4V

NASA Astrophysics Data System (ADS)

Moore, John A.; Barton, Nathan R.; Florando, Jeff; Mulay, Rupalee; Kumar, Mukul

2017-10-01

Ti-6Al-4V is an alloy of titanium that dominates titanium usage in applications ranging from mass-produced consumer goods to high-end aerospace parts. The material’s structure on a microscale is known to affect its mechanical properties but these effects are not fully understood. Specifically, this work will address the effects of low volume fraction intergranular β phase on Ti-6Al-4V’s mechanical response during the transition from elastic to plastic deformation. A crystal plasticity-based finite element model is used to fully resolve the deformation of the β phase for the first time. This high fidelity model captures mechanisms difficult to access via experiments or lower fidelity models. The results are used to assess lower fidelity modeling assumptions and identify phenomena that have ramifications for failure of the material.

Improving Mixed Variable Optimization of Computational and Model Parameters Using Multiple Surrogate Functions

DTIC Science & Technology

2008-03-01

multiplicative corrections as well as space mapping transformations for models defined over a lower dimensional space. A corrected surrogate model for the...correction functions used in [72]. If the low fidelity model g(x̃) is defined over a lower dimensional space then a space mapping transformation is...required. As defined in [21, 72], space mapping is a method of mapping between models of different dimensionality or fidelity. Let P denote the space

Sources of variation in breeding-ground fidelity of mallards (Anas platyrhynchos)

USGS Publications Warehouse

Doherty, P.F.; Nichols, J.D.; Tautin, J.; Voelzer, J.E.; Smith, G.W.; Benning, D.S.; Bentley, V.R.; Bidwell, J.K.; Bollinger, K.S.; Brazda, A.R.; Buelna, E.K.; Goldsberry, J.R.; King, R.J.; Roetker, F.H.; Solberg, J.W.; Thorpe, P.P.; Wortham, J.S.

2002-01-01

Generalizations used to support hypotheses about the evolution of fidelity to breeding areas in birds include the tendency for fidelity to be greater in adult birds than in yearlings. In ducks, in contrast to most bird species, fidelity is thought to be greater among females than males. Researchers have suggested that fidelity in ducks is positively correlated with pond availability. However, most estimates of fidelity on which these inferences have been based represent functions of survival and recapture-resighting probabilities in addition to fidelity. We applied the modeling approach developed by Burnham to recapture and band recovery data of mallard ducks to test the above hypotheses about fidelity. We found little evidence of sex differences in adult philopatry, with females being slightly more philopatric than males in one study area, but not in a second study area. However, yearling females were more philopatric than yearling males in both study areas. We found that adults were generally more philopatric than yearlings. We could find no relationship between fidelity and pond availability. Our results, while partially supporting current theory concerning sex and age differences in philopatry, suggest that adult male mallards are more philopatric than once thought, and we recommend that other generalizations about philopatry be revisited with proper estimation techniques.

Modeling of Passive Acoustic Liners from High Fidelity Numerical Simulations

NASA Astrophysics Data System (ADS)

Ferrari, Marcello do Areal Souto

Noise reduction in aviation has been an important focus of study in the last few decades. One common solution is setting up acoustic liners in the internal walls of the engines. However, measurements in the laboratory with liners are expensive and time consuming. The present work proposes a nonlinear physics-based time domain model to predict the acoustic behavior of a given liner in a defined flow condition. The parameters of the model are defined by analysis of accurate numerical solutions of the flow obtained from a high-fidelity numerical code. The length of the cavity is taken into account by using an analytical procedure to account for internal reflections in the interior of the cavity. Vortices and jets originated from internal flow separations are confirmed to be important mechanisms of sound absorption, which defines the overall efficiency of the liner. Numerical simulations at different frequency, geometry and sound pressure level are studied in detail to define the model parameters. Comparisons with high-fidelity numerical simulations show that the proposed model is accurate, robust, and can be used to define a boundary condition simulating a liner in a high-fidelity code.

SUPIN: A Computational Tool for Supersonic Inlet Design

NASA Technical Reports Server (NTRS)

Slater, John W.

2016-01-01

A computational tool named SUPIN is being developed to design and analyze the aerodynamic performance of supersonic inlets. The inlet types available include the axisymmetric pitot, three-dimensional pitot, axisymmetric outward-turning, two-dimensional single-duct, two-dimensional bifurcated-duct, and streamline-traced inlets. The aerodynamic performance is characterized by the flow rates, total pressure recovery, and drag. The inlet flow-field is divided into parts to provide a framework for the geometry and aerodynamic modeling. Each part of the inlet is defined in terms of geometric factors. The low-fidelity aerodynamic analysis and design methods are based on analytic, empirical, and numerical methods which provide for quick design and analysis. SUPIN provides inlet geometry in the form of coordinates, surface angles, and cross-sectional areas. SUPIN can generate inlet surface grids and three-dimensional, structured volume grids for use with higher-fidelity computational fluid dynamics (CFD) analysis. Capabilities highlighted in this paper include the design and analysis of streamline-traced external-compression inlets, modeling of porous bleed, and the design and analysis of mixed-compression inlets. CFD analyses are used to verify the SUPIN results.

Population coding in sparsely connected networks of noisy neurons.

PubMed

Tripp, Bryan P; Orchard, Jeff

2012-01-01

This study examines the relationship between population coding and spatial connection statistics in networks of noisy neurons. Encoding of sensory information in the neocortex is thought to require coordinated neural populations, because individual cortical neurons respond to a wide range of stimuli, and exhibit highly variable spiking in response to repeated stimuli. Population coding is rooted in network structure, because cortical neurons receive information only from other neurons, and because the information they encode must be decoded by other neurons, if it is to affect behavior. However, population coding theory has often ignored network structure, or assumed discrete, fully connected populations (in contrast with the sparsely connected, continuous sheet of the cortex). In this study, we modeled a sheet of cortical neurons with sparse, primarily local connections, and found that a network with this structure could encode multiple internal state variables with high signal-to-noise ratio. However, we were unable to create high-fidelity networks by instantiating connections at random according to spatial connection probabilities. In our models, high-fidelity networks required additional structure, with higher cluster factors and correlations between the inputs to nearby neurons.

High-Fidelity Single-Shot Readout for a Spin Qubit via an Enhanced Latching Mechanism

NASA Astrophysics Data System (ADS)

Harvey-Collard, Patrick; D'Anjou, Benjamin; Rudolph, Martin; Jacobson, N. Tobias; Dominguez, Jason; Ten Eyck, Gregory A.; Wendt, Joel R.; Pluym, Tammy; Lilly, Michael P.; Coish, William A.; Pioro-Ladrière, Michel; Carroll, Malcolm S.

2018-04-01

The readout of semiconductor spin qubits based on spin blockade is fast but suffers from a small charge signal. Previous work suggested large benefits from additional charge mapping processes; however, uncertainties remain about the underlying mechanisms and achievable fidelity. In this work, we study the single-shot fidelity and limiting mechanisms for two variations of an enhanced latching readout. We achieve average single-shot readout fidelities greater than 99.3% and 99.86% for the conventional and enhanced readout, respectively, the latter being the highest to date for spin blockade. The signal amplitude is enhanced to a full one-electron signal while preserving the readout speed. Furthermore, layout constraints are relaxed because the charge sensor signal is no longer dependent on being aligned with the conventional (2,0)-(1,1) charge dipole. Silicon donor-quantum-dot qubits are used for this study, for which the dipole insensitivity substantially relaxes donor placement requirements. One of the readout variations also benefits from a parametric lifetime enhancement by replacing the spin-relaxation process with a charge-metastable one. This provides opportunities to further increase the fidelity. The relaxation mechanisms in the different regimes are investigated. This work demonstrates a readout that is fast, has a one-electron signal, and results in higher fidelity. It further predicts that going beyond 99.9% fidelity in a few microseconds of measurement time is within reach.

CTF (Subchannel) Calculations and Validation L3:VVI.H2L.P15.01

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, Natalie

The goal of the Verification and Validation Implementation (VVI) High to Low (Hi2Lo) process is utilizing a validated model in a high resolution code to generate synthetic data for improvement of the same model in a lower resolution code. This process is useful in circumstances where experimental data does not exist or it is not sufficient in quantity or resolution. Data from the high-fidelity code is treated as calibration data (with appropriate uncertainties and error bounds) which can be used to train parameters that affect solution accuracy in the lower-fidelity code model, thereby reducing uncertainty. This milestone presents a demonstrationmore » of the Hi2Lo process derived in the VVI focus area. The majority of the work performed herein describes the steps of the low-fidelity code used in the process with references to the work detailed in the companion high-fidelity code milestone (Reference 1). The CASL low-fidelity code used to perform this work was Cobra Thermal Fluid (CTF) and the high-fidelity code was STAR-CCM+ (STAR). The master branch version of CTF (pulled May 5, 2017 – Reference 2) was utilized for all CTF analyses performed as part of this milestone. The statistical and VVUQ components of the Hi2Lo framework were performed using Dakota version 6.6 (release date May 15, 2017 – Reference 3). Experimental data from Westinghouse Electric Company (WEC – Reference 4) was used throughout the demonstrated process to compare with the high-fidelity STAR results. A CTF parameter called Beta was chosen as the calibration parameter for this work. By default, Beta is defined as a constant mixing coefficient in CTF and is essentially a tuning parameter for mixing between subchannels. Since CTF does not have turbulence models like STAR, Beta is the parameter that performs the most similar function to the turbulence models in STAR. The purpose of the work performed in this milestone is to tune Beta to an optimal value that brings the CTF results closer to those measured in the WEC experiments.« less

FAST TRACK COMMUNICATION: Ground-state fidelity and entanglement entropy for the quantum three-state Potts model in one spatial dimension

NASA Astrophysics Data System (ADS)

Dai, Yan-Wei; Hu, Bing-Quan; Zhao, Jian-Hui; Zhou, Huan-Qiang

2010-09-01

The ground-state fidelity per lattice site is computed for the quantum three-state Potts model in a transverse magnetic field on an infinite-size lattice in one spatial dimension in terms of the infinite matrix product state algorithm. It is found that, on the one hand, a pinch point is identified on the fidelity surface around the critical point, and on the other hand, the ground-state fidelity per lattice site exhibits bifurcations at pseudo critical points for different values of the truncation dimension, which in turn approach the critical point as the truncation dimension becomes large. This implies that the ground-state fidelity per lattice site enables us to capture spontaneous symmetry breaking when the control parameter crosses the critical value. In addition, a finite-entanglement scaling of the von Neumann entropy is performed with respect to the truncation dimension, resulting in a precise determination of the central charge at the critical point. Finally, we compute the transverse magnetization, from which the critical exponent β is extracted from the numerical data.

Teacher Fidelity to a Physical Education Curricular Model and Physical Activity Outcomes

ERIC Educational Resources Information Center

Stylianou, Michalis; Kloeppel, Tiffany; Kulinna, Pamela; van der Mars, Han

2016-01-01

Background: This study was informed by the bodies of literature emphasizing the role of physical education in promoting physical activity (PA) and addressing teacher fidelity to curricular models. Purpose: The purpose of this study was to compare student PA levels, lesson context, and teacher PA promotion behavior among classes where teachers were…

Injury representation against ballistic threats using three novel numerical models.

PubMed

Breeze, Johno; Fryer, R; Pope, D; Clasper, J

2017-06-01

Injury modelling of ballistic threats is a valuable tool for informing policy on personal protective equipment and other injury mitigation methods. Currently, the Ministry of Defence (MoD) and Centre for Protection of National Infrastructure (CPNI) are focusing on the development of three interlinking numerical models, each of a different fidelity, to answer specific questions on current threats. High-fidelity models simulate the physical events most realistically, and will be used in the future to test the medical effectiveness of personal armour systems. They are however generally computationally intensive, slow running and much of the experimental data to base their algorithms on do not yet exist. Medium fidelity models, such as the personnel vulnerability simulation (PVS), generally use algorithms based on physical or engineering estimations of interaction. This enables a reasonable representation of reality and greatly speeds up runtime allowing full assessments of the entire body area to be undertaken. Low-fidelity models such as the human injury predictor (HIP) tool generally use simplistic algorithms to make injury predictions. Individual scenarios can be run very quickly and hence enable statistical casualty assessments of large groups, where significant uncertainty concerning the threat and affected population exist. HIP is used to simulate the blast and penetrative fragmentation effects of a terrorist detonation of an improvised explosive device within crowds of people in metropolitan environments. This paper describes the collaboration between MoD and CPNI using an example of all three fidelities of injury model and to highlight future areas of research that are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Modeling and Simulation of Upset-Inducing Disturbances for Digital Systems in an Electromagnetic Reverberation Chamber

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo

2014-01-01

This report describes a modeling and simulation approach for disturbance patterns representative of the environment experienced by a digital system in an electromagnetic reverberation chamber. The disturbance is modeled by a multi-variate statistical distribution based on empirical observations. Extended versions of the Rejection Samping and Inverse Transform Sampling techniques are developed to generate multi-variate random samples of the disturbance. The results show that Inverse Transform Sampling returns samples with higher fidelity relative to the empirical distribution. This work is part of an ongoing effort to develop a resilience assessment methodology for complex safety-critical distributed systems.

Crystal plasticity modeling of β phase deformation in Ti-6Al-4V

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, John A.; Barton, Nathan R.; Florando, Jeff

Ti-6Al-4V is an alloy of titanium that dominates titanium usage in applications ranging from mass-produced consumer goods to high-end aerospace parts. The material's structure on a microscale is known to affect its mechanical properties but these effects are not fully understood. Specifically, this work will address the effects of low volume fraction intergranular β phase on Ti-6Al-4V's mechanical response during the transition from elastic to plastic deformation. A crystal plasticity-based finite element model is used to fully resolve the deformation of the β phase for the first time. This high fidelity model captures mechanisms difficult to access via experiments ormore » lower fidelity models. Lastly, the results are used to assess lower fidelity modeling assumptions and identify phenomena that have ramifications for failure of the material.« less

Crystal plasticity modeling of β phase deformation in Ti-6Al-4V

DOE PAGES

Moore, John A.; Barton, Nathan R.; Florando, Jeff; ...

2017-08-24

Ti-6Al-4V is an alloy of titanium that dominates titanium usage in applications ranging from mass-produced consumer goods to high-end aerospace parts. The material's structure on a microscale is known to affect its mechanical properties but these effects are not fully understood. Specifically, this work will address the effects of low volume fraction intergranular β phase on Ti-6Al-4V's mechanical response during the transition from elastic to plastic deformation. A crystal plasticity-based finite element model is used to fully resolve the deformation of the β phase for the first time. This high fidelity model captures mechanisms difficult to access via experiments ormore » lower fidelity models. Lastly, the results are used to assess lower fidelity modeling assumptions and identify phenomena that have ramifications for failure of the material.« less

Strong homing does not predict high site fidelity in juvenile reef fishes

NASA Astrophysics Data System (ADS)

Streit, Robert P.; Bellwood, David R.

2018-03-01

After being displaced, juvenile reef fishes are able to return home over large distances. This strong homing behaviour is extraordinary and may allow insights into the longer-term spatial ecology of fish communities. For example, it appears intuitive that strong homing behaviour should be indicative of long-term site fidelity. However, this connection has rarely been tested. We quantified the site fidelity of juvenile fishes of four species after returning home following displacement. Two species, parrotfishes and Pomacentrus moluccensis, showed significantly reduced site fidelity after returning home. On average, they disappeared from their home sites almost 3 d earlier than expected. Mortality or competitive exclusion does not seem to be the main reasons for their disappearance. Rather, we suggest an increased propensity to relocate after encountering alternative reef locations while homing. It appears that some juvenile fishes may have a higher innate spatial flexibility than their strict homing drive suggests.

Experimental purification of two-atom entanglement.

PubMed

Reichle, R; Leibfried, D; Knill, E; Britton, J; Blakestad, R B; Jost, J D; Langer, C; Ozeri, R; Seidelin, S; Wineland, D J

2006-10-19

Entanglement is a necessary resource for quantum applications--entanglement established between quantum systems at different locations enables private communication and quantum teleportation, and facilitates quantum information processing. Distributed entanglement is established by preparing an entangled pair of quantum particles in one location, and transporting one member of the pair to another location. However, decoherence during transport reduces the quality (fidelity) of the entanglement. A protocol to achieve entanglement 'purification' has been proposed to improve the fidelity after transport. This protocol uses separate quantum operations at each location and classical communication to distil high-fidelity entangled pairs from lower-fidelity pairs. Proof-of-principle experiments distilling entangled photon pairs have been carried out. However, these experiments obtained distilled pairs with a low probability of success and required destruction of the entangled pairs, rendering them unavailable for further processing. Here we report efficient and non-destructive entanglement purification with atomic quantum bits. Two noisy entangled pairs were created and distilled into one higher-fidelity pair available for further use. Success probabilities were above 35 per cent. The many applications of entanglement purification make it one of the most important techniques in quantum information processing.

Telemetry-Determined Habitat Use Informs Multi-Species Habitat Management in an Urban Harbour

NASA Astrophysics Data System (ADS)

Rous, Andrew M.; Midwood, Jonathon D.; Gutowsky, Lee F. G.; Lapointe, Nicolas W. R.; Portiss, Rick; Sciscione, Thomas; Wells, Mathew G.; Doka, Susan E.; Cooke, Steven J.

2017-01-01

Widespread human development has led to impairment of freshwater coastal wetlands and embayments, which provide critical and unique habitat for many freshwater fish species. This is particularly evident in the Laurentian Great Lakes, where such habitats have been severely altered over the last century as a result of industrial activities, urbanization, dredging and infilling. In Toronto Harbour, extensive restoration efforts have been directed towards improving the amount and quality of aquatic habitat, especially for fishes. To evaluate the effectiveness of this restoration work, use of the restored area by both target species and the fish community as a whole must be assessed. Individuals from four species (Common Carp, Largemouth Bass, Northern Pike and Yellow Perch) were tagged and tracked continuously for 1 year using an acoustic telemetry array in Toronto Harbour area of Lake Ontario. Daily site fidelity was estimated using a mixed-effects logistic regression model. Daily site fidelity was influenced by habitat restoration and its interactions with species and body size, as well as season and its interactions with species and body size. Daily site fidelity was higher in restored sites compared to non-restored sites for Yellow Perch and Northern Pike, but lower for Largemouth Bass and Common Carp. For all species, daily site fidelity estimates were highest during the summer and lowest during autumn. The approach used here has merit for evaluating restoration success and informing future habitat management activities. Creating diverse habitats that serve multiple functions and species are more desirable than single-function-oriented or single-species-oriented designs.

Telemetry-Determined Habitat Use Informs Multi-Species Habitat Management in an Urban Harbour.

PubMed

Rous, Andrew M; Midwood, Jonathon D; Gutowsky, Lee F G; Lapointe, Nicolas W R; Portiss, Rick; Sciscione, Thomas; Wells, Mathew G; Doka, Susan E; Cooke, Steven J

2017-01-01

Widespread human development has led to impairment of freshwater coastal wetlands and embayments, which provide critical and unique habitat for many freshwater fish species. This is particularly evident in the Laurentian Great Lakes, where such habitats have been severely altered over the last century as a result of industrial activities, urbanization, dredging and infilling. In Toronto Harbour, extensive restoration efforts have been directed towards improving the amount and quality of aquatic habitat, especially for fishes. To evaluate the effectiveness of this restoration work, use of the restored area by both target species and the fish community as a whole must be assessed. Individuals from four species (Common Carp, Largemouth Bass, Northern Pike and Yellow Perch) were tagged and tracked continuously for 1 year using an acoustic telemetry array in Toronto Harbour area of Lake Ontario. Daily site fidelity was estimated using a mixed-effects logistic regression model. Daily site fidelity was influenced by habitat restoration and its interactions with species and body size, as well as season and its interactions with species and body size. Daily site fidelity was higher in restored sites compared to non-restored sites for Yellow Perch and Northern Pike, but lower for Largemouth Bass and Common Carp. For all species, daily site fidelity estimates were highest during the summer and lowest during autumn. The approach used here has merit for evaluating restoration success and informing future habitat management activities. Creating diverse habitats that serve multiple functions and species are more desirable than single-function-oriented or single-species-oriented designs.

The coupling of the neutron transport application RATTLESNAKE to the nuclear fuels performance application BISON under the MOOSE framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gleicher, Frederick N.; Williamson, Richard L.; Ortensi, Javier

The MOOSE neutron transport application RATTLESNAKE was coupled to the fuels performance application BISON to provide a higher fidelity tool for fuel performance simulation. This project is motivated by the desire to couple a high fidelity core analysis program (based on the self-adjoint angular flux equations) to a high fidelity fuel performance program, both of which can simulate on unstructured meshes. RATTLESNAKE solves self-adjoint angular flux transport equation and provides a sub-pin level resolution of the multigroup neutron flux with resonance treatment during burnup or a fast transient. BISON solves the coupled thermomechanical equations for the fuel on a sub-millimetermore » scale. Both applications are able to solve their respective systems on aligned and unaligned unstructured finite element meshes. The power density and local burnup was transferred from RATTLESNAKE to BISON with the MOOSE Multiapp transfer system. Multiple depletion cases were run with one-way data transfer from RATTLESNAKE to BISON. The eigenvalues are shown to agree well with values obtained from the lattice physics code DRAGON. The one-way data transfer of power density is shown to agree with the power density obtained from an internal Lassman-style model in BISON.« less

Landsat multispectral sharpening using a sensor system model and panchromatic image

USGS Publications Warehouse

Lemeshewsky, G.P.; ,

2003-01-01

The thematic mapper (TM) sensor aboard Landsats 4, 5 and enhanced TM plus (ETM+) on Landsat 7 collect imagery at 30-m sample distance in six spectral bands. New with ETM+ is a 15-m panchromatic (P) band. With image sharpening techniques, this higher resolution P data, or as an alternative, the 10-m (or 5-m) P data of the SPOT satellite, can increase the spatial resolution of the multispectral (MS) data. Sharpening requires that the lower resolution MS image be coregistered and resampled to the P data before high spatial frequency information is transferred to the MS data. For visual interpretation and machine classification tasks, it is important that the sharpened data preserve the spectral characteristics of the original low resolution data. A technique was developed for sharpening (in this case, 3:1 spatial resolution enhancement) visible spectral band data, based on a model of the sensor system point spread function (PSF) in order to maintain spectral fidelity. It combines high-pass (HP) filter sharpening methods with iterative image restoration to reduce degradations caused by sensor-system-induced blurring and resembling. Also there is a spectral fidelity requirement: sharpened MS when filtered by the modeled degradations should reproduce the low resolution source MS. Quantitative evaluation of sharpening performance was made by using simulated low resolution data generated from digital color-IR aerial photography. In comparison to the HP-filter-based sharpening method, results for the technique in this paper with simulated data show improved spectral fidelity. Preliminary results with TM 30-m visible band data sharpened with simulated 10-m panchromatic data are promising but require further study.

Multifamily Group Psychoeducation in New York State: Implementation and Fidelity Outcomes.

PubMed

Kealey, Edith M; Leckman-Westin, Emily; Jewell, Thomas C; Finnerty, Molly T

2015-11-01

The study examined implementation outcomes from a large state initiative to support dissemination of multifamily group (MFG) psychoeducation in outpatient mental health settings. Thirty-one sites participated in the project. Baseline training in the MFG model was followed by monthly expert consultation delivered in either a group (16 sites) or individual format (15 sites). Research staff assessed fidelity to the MFG model by telephone at baseline and 12, 18, and 24 months and documented time to completion of three key milestones: holding a family joining session, a family educational workshop, and an MFG meeting. Intent-to-train analyses found that 12 sites (39%) achieved high fidelity to the MFG model, and 20 (65%) achieved moderate or high fidelity. Mean scores on the Family Psychoeducation Fidelity Assessment Scale increased over time. Twenty-five sites (81%) conducted at least one joining session, and 20 (65%) conducted at least one MFG. Mean±SD time from baseline to the first group was 11.75±4.78 months. Programs that held the first joining session within four to 12 months after training were significantly more likely than programs that did not to conduct a group (p<.05). No significant differences were found by consultation format. Implementation of moderate- to high-fidelity MFG programs in routine outpatient mental health settings is feasible. Sites that moved very quickly or very slowly in early implementation stages were less likely to be successful in conducting an MFG. More research on the efficiency and effectiveness of consultation formats is needed to guide future implementation efforts.

EBT Fidelity Trajectories Across Training Cohorts Using the Interagency Collaborative Team Strategy

PubMed Central

Hecht, Debra; Aarons, Greg; Fettes, Danielle; Hurlburt, Michael; Ledesma, Karla

2015-01-01

The Interdisciplinary Collaborative Team (ICT) strategy uses front-line providers as adaptation, training and quality control agents for multi-agency EBT implementation. This study tests whether an ICT transmits fidelity to subsequent provider cohorts. SafeCare was implemented by home visitors from multiple community-based agencies contracting with child welfare. Client-reported fidelity trajectories for 5,769 visits, 957 clients and 45 providers were compared using three-level growth models. Provider cohorts trained and live-coached by the ICT attained benchmark fidelity after 12 weeks, and this was sustained. Hispanic clients reported high cultural competency, supporting a cultural adaptation crafted by the ICT. PMID:25586878

EBT Fidelity Trajectories Across Training Cohorts Using the Interagency Collaborative Team Strategy.

PubMed

Chaffin, Mark; Hecht, Debra; Aarons, Greg; Fettes, Danielle; Hurlburt, Michael; Ledesma, Karla

2016-03-01

The Interdisciplinary Collaborative Team (ICT) strategy uses front-line providers as adaptation, training and quality control agents for multi-agency EBT implementation. This study tests whether an ICT transmits fidelity to subsequent provider cohorts. SafeCare was implemented by home visitors from multiple community-based agencies contracting with child welfare. Client-reported fidelity trajectories for 5,769 visits, 957 clients and 45 providers were compared using three-level growth models. Provider cohorts trained and live-coached by the ICT attained benchmark fidelity after 12 weeks, and this was sustained. Hispanic clients reported high cultural competency, supporting a cultural adaptation crafted by the ICT.

Facilitating higher-fidelity simulations of axial compressor instability and other turbomachinery flow conditions

NASA Astrophysics Data System (ADS)

Herrick, Gregory Paul

The quest to accurately capture flow phenomena with length-scales both short and long and to accurately represent complex flow phenomena within disparately sized geometry inspires a need for an efficient, high-fidelity, multi-block structured computational fluid dynamics (CFD) parallel computational scheme. This research presents and demonstrates a more efficient computational method by which to perform multi-block structured CFD parallel computational simulations, thus facilitating higher-fidelity solutions of complicated geometries (due to the inclusion of grids for "small'' flow areas which are often merely modeled) and their associated flows. This computational framework offers greater flexibility and user-control in allocating the resource balance between process count and wall-clock computation time. The principal modifications implemented in this revision consist of a "multiple grid block per processing core'' software infrastructure and an analytic computation of viscous flux Jacobians. The development of this scheme is largely motivated by the desire to simulate axial compressor stall inception with more complete gridding of the flow passages (including rotor tip clearance regions) than has been previously done while maintaining high computational efficiency (i.e., minimal consumption of computational resources), and thus this paradigm shall be demonstrated with an examination of instability in a transonic axial compressor. However, the paradigm presented herein facilitates CFD simulation of myriad previously impractical geometries and flows and is not limited to detailed analyses of axial compressor flows. While the simulations presented herein were technically possible under the previous structure of the subject software, they were much less computationally efficient and thus not pragmatically feasible; the previous research using this software to perform three-dimensional, full-annulus, time-accurate, unsteady, full-stage (with sliding-interface) simulations of rotating stall inception in axial compressors utilized tip clearance periodic models, while the scheme here is demonstrated by a simulation of axial compressor stall inception utilizing gridded rotor tip clearance regions. As will be discussed, much previous research---experimental, theoretical, and computational---has suggested that understanding clearance flow behavior is critical to understanding stall inception, and previous computational research efforts which have used tip clearance models have begged the question, "What about the clearance flows?''. This research begins to address that question.

Utilizing Adjoint-Based Error Estimates for Surrogate Models to Accurately Predict Probabilities of Events

DOE PAGES

Butler, Troy; Wildey, Timothy

2018-01-01

In thist study, we develop a procedure to utilize error estimates for samples of a surrogate model to compute robust upper and lower bounds on estimates of probabilities of events. We show that these error estimates can also be used in an adaptive algorithm to simultaneously reduce the computational cost and increase the accuracy in estimating probabilities of events using computationally expensive high-fidelity models. Specifically, we introduce the notion of reliability of a sample of a surrogate model, and we prove that utilizing the surrogate model for the reliable samples and the high-fidelity model for the unreliable samples gives preciselymore » the same estimate of the probability of the output event as would be obtained by evaluation of the original model for each sample. The adaptive algorithm uses the additional evaluations of the high-fidelity model for the unreliable samples to locally improve the surrogate model near the limit state, which significantly reduces the number of high-fidelity model evaluations as the limit state is resolved. Numerical results based on a recently developed adjoint-based approach for estimating the error in samples of a surrogate are provided to demonstrate (1) the robustness of the bounds on the probability of an event, and (2) that the adaptive enhancement algorithm provides a more accurate estimate of the probability of the QoI event than standard response surface approximation methods at a lower computational cost.« less

Utilizing Adjoint-Based Error Estimates for Surrogate Models to Accurately Predict Probabilities of Events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, Troy; Wildey, Timothy

In thist study, we develop a procedure to utilize error estimates for samples of a surrogate model to compute robust upper and lower bounds on estimates of probabilities of events. We show that these error estimates can also be used in an adaptive algorithm to simultaneously reduce the computational cost and increase the accuracy in estimating probabilities of events using computationally expensive high-fidelity models. Specifically, we introduce the notion of reliability of a sample of a surrogate model, and we prove that utilizing the surrogate model for the reliable samples and the high-fidelity model for the unreliable samples gives preciselymore » the same estimate of the probability of the output event as would be obtained by evaluation of the original model for each sample. The adaptive algorithm uses the additional evaluations of the high-fidelity model for the unreliable samples to locally improve the surrogate model near the limit state, which significantly reduces the number of high-fidelity model evaluations as the limit state is resolved. Numerical results based on a recently developed adjoint-based approach for estimating the error in samples of a surrogate are provided to demonstrate (1) the robustness of the bounds on the probability of an event, and (2) that the adaptive enhancement algorithm provides a more accurate estimate of the probability of the QoI event than standard response surface approximation methods at a lower computational cost.« less

Intermediate Fidelity Closed Brayton Cycle Power Conversion Model

NASA Technical Reports Server (NTRS)

Lavelle, Thomas M.; Khandelwal, Suresh; Owen, Albert K.

2006-01-01

This paper describes the implementation of an intermediate fidelity model of a closed Brayton Cycle power conversion system (Closed Cycle System Simulation). The simulation is developed within the Numerical Propulsion Simulation System architecture using component elements from earlier models. Of particular interest, and power, is the ability of this new simulation system to initiate a more detailed analysis of compressor and turbine components automatically and to incorporate the overall results into the general system simulation.

Systematic evaluation of implementation fidelity of complex interventions in health and social care

PubMed Central

2010-01-01

Background Evaluation of an implementation process and its fidelity can give insight into the 'black box' of interventions. However, a lack of standardized methods for studying fidelity and implementation process have been reported, which might be one reason for the fact that few prior studies in the field of health service research have systematically evaluated interventions' implementation processes. The aim of this project is to systematically evaluate implementation fidelity and possible factors influencing fidelity of complex interventions in health and social care. Methods A modified version of The Conceptual Framework for Implementation Fidelity will be used as a conceptual model for the evaluation. The modification implies two additional moderating factors: context and recruitment. A systematic evaluation process was developed. Multiple case study method is used to investigate implementation of three complex health service interventions. Each case will be investigated in depth and longitudinally, using both quantitative and qualitative methods. Discussion This study is the first attempt to empirically test The Conceptual Framework for Implementation Fidelity. The study can highlight mechanism and factors of importance when implementing complex interventions. Especially the role of the moderating factors on implementation fidelity can be clarified. Trial Registration Supported Employment, SE, among people with severe mental illness -- a randomized controlled trial: NCT00960024. PMID:20815872

Thermal Protection System Mass Estimating Relationships for Blunt-Body, Earth Entry Spacecraft

NASA Technical Reports Server (NTRS)

Sepka, Steven A.; Samareh, Jamshid A.

2015-01-01

System analysis and design of any entry system must balance the level fidelity for each discipline against the project timeline. One way to inject high fidelity analysis earlier in the design effort is to develop surrogate models for the high-fidelity disciplines. Surrogate models for the Thermal Protection System (TPS) are formulated as Mass Estimating Relationships (MERs). The TPS MERs are presented that predict the amount of TPS necessary for safe Earth entry for blunt-body spacecraft using simple correlations that closely match estimates from NASA's high-fidelity ablation modeling tool, the Fully Implicit Ablation and Thermal Analysis Program (FIAT). These MERs provide a first order estimate for rapid feasibility studies. There are 840 different trajectories considered in this study, and each TPS MER has a peak heating limit. MERs for the vehicle forebody include the ablators Phenolic Impregnated Carbon Ablator (PICA) and Carbon Phenolic atop Advanced Carbon-Carbon. For the aftbody, the materials are Silicone Impregnated Reusable Ceramic Ablator (SIRCA), Acusil II, SLA-561V, and LI-900. The MERs are accurate to within 14% (at one standard deviation) of FIAT prediction, and the most any MER under predicts FIAT TPS thickness is 18.7%. This work focuses on the development of these MERs, the resulting equations, model limitations, and model accuracy.

The Effect of Tow Shearing on Reinforcement Positional Fidelity in the Manufacture of a Continuous Fiber Reinforced Thermoplastic Matrix Composite via Pultrusion-Like Processing of Commingled Feedstock

NASA Astrophysics Data System (ADS)

Warlick, Kent M.

While the addition of short fiber to 3D printed articles has increased structural performance, ultimate gains will only be realized through the introduction of continuous reinforcement placed along pre-planned load paths. Most additive manufacturing research focusing on the addition of continuous reinforcement has revolved around utilization of a prefrabricated composite filament or a fiber and matrix mixed within a hot end prior to deposition on a printing surface such that conventional extrusion based FDM can be applied. Although stronger 3D printed parts can be made in this manner, high quality homogenous composites are not possible due to fiber dominated regions, matrix dominated regions, and voids present between adjacent filaments. Conventional composite manufacturing processes are much better at creating homogeneous composites; however, the layer by layer approach in which they are made is inhibiting the alignment of reinforcement with loads. Automated Fiber Placement techniques utilize in plane bending deformation of the tow to facilitate tow steering. Due to buckling fibers on the inner radius of curves, manufacturers recommend a minimum curvature for path placement with this technique. A method called continuous tow shearing has shown promise to enable the placement of tows in complex patterns without tow buckling, spreading, and separation inherent in conventional forms of automated reinforcement positioning. The current work employs fused deposition modeling hardware and the continuous tow shearing technique to manufacture high quality fiber reinforced composites with high positional fidelity, varying continuous reinforcement orientations within a layer, and plastic elements incorporated enabling the ultimate gains in structural performance possible. A mechanical system combining concepts of additive manufacturing with fiber placement via filament winding was developed. Paths with and without tension inherent in filament winding were analyzed through microscopy in order to examine best and worst case scenarios. High quality fiber reinforced composite materials, in terms of low void content, high fiber volume fractions and homogeneity in microstructure, were manufactured in both of these scenarios. In order to improve fidelity and quality in fiber path transition regions, a forced air cooling manifold was designed, printed, and implemented into the current system. To better understand the composite performance that results from varying pertinent manufacturing parameters, the effect of feed rate, hot end temperature, forced air cooling, and deposition surface (polypropylene and previously deposited glass polypropylene commingled tow) on interply performance, microstructure, and positional fidelity were analyzed. Interply performance, in terms of average maximum load and average peel strength, was quantified through a t-peel test of the bonding quality between two surfaces. With use of forced air cooling, minor decreases in average peel strength were present due to a reduction in tow deposition temperature which was found to be the variable most indicative of performance. Average maximum load was comparable between the forced air cooled and non-air cooled samples. Microstructure was evaluated through characterization of composite area, void content, and flash percentage. Low void contents mostly between five to seven percent were attained. Further reduction of this void content to two percent is possible through higher processing temperatures; however, reduced composite area, low average peel strength performance, and the presence of smoke during manufacturing implied thermal degradation of the polypropylene matrix occurred in these samples with higher processing temperatures. Positional fidelity was measured through calculations of shear angle, shift width, and error of a predefined path. While positional fidelity variation was low with a polypropylene deposition surface, forced air cooling is necessary to achieve fidelity on top of an already deposited tow surface as evident by the fifty-six percent reduction in error tolerance profile achieved. Lastly, proof of concept articles with unique fiber paths and neat plastic elements incorporated were produced to demonstrate fiber placement along pre-planned load paths and the ability to achieve greater structural efficiency through the use of less material. The results show that high positional fidelity and high quality composites can be produced through the use of the tow shearing technique implemented in the developed mechanical system. The implementation of forced air cooling was critical in achieving fidelity and quality in transition regions. Alignment of continuous reinforcement with pre-planned load paths was demonstrated in the proof of concept article with varying fiber orientations within a layer. Combining fused deposition modeling of plastic with the placement of continuous reinforcement enabled a honeycomb composite to be produced with higher specific properties than traditional composites. Thus, the current system demonstrated a greater capability of achieving ultimate gains in structural performance than previously possible.

Fidelity and moderating factors in complex interventions: a case study of a continuum of care program for frail elderly people in health and social care

PubMed Central

2012-01-01

Background Prior studies measuring fidelity of complex interventions have mainly evaluated adherence, and not taken factors affecting adherence into consideration. A need for studies that clarify the concept of fidelity and the function of factors moderating fidelity has been emphasized. The aim of the study was to systematically evaluate implementation fidelity and possible factors influencing fidelity of a complex care continuum intervention for frail elderly people. Methods The intervention was a systematization of the collaboration between a nurse with geriatric expertise situated at the emergency department, the hospital ward staff, and a multi-professional team with a case manager in the municipal care services for older people. Implementation was evaluated between September 2008 and May 2010 with observations of work practices, stakeholder interviews, and document analysis according to a modified version of The Conceptual Framework for Implementation Fidelity. Results A total of 16 of the 18 intervention components were to a great extent delivered as planned, while some new components were added to the model. No changes in the frequency or duration of the 18 components were observed, but the dose of the added components varied over time. Changes in fidelity were caused in a complex, interrelated fashion by all the moderating factors in the framework, i.e., context, staff and participant responsiveness, facilitation, recruitment, and complexity. Discussion The Conceptual Framework for Implementation Fidelity was empirically useful and included comprehensive measures of factors affecting fidelity. Future studies should focus on developing the framework with regard to how to investigate relationships between the moderating factors and fidelity over time. Trial registration ClinicalTrials.gov, NCT01260493. PMID:22436121

The Cascading Effects of Multiple Dimensions of Implementation on Program Outcomes: a Test of a Theoretical Model.

PubMed

Berkel, Cady; Mauricio, Anne M; Sandler, Irwin N; Wolchik, Sharlene A; Gallo, Carlos G; Brown, C Hendricks

2017-12-14

This study tests a theoretical cascade model in which multiple dimensions of facilitator delivery predict indicators of participant responsiveness, which in turn lead to improvements in targeted program outcomes. An effectiveness trial of the 10-session New Beginnings Program for divorcing families was implemented in partnership with four county-level family courts. This study included 366 families assigned to the intervention condition who attended at least one session. Independent observers provided ratings of program delivery (i.e., fidelity to the curriculum and process quality). Facilitators reported on parent attendance and parents' competence in home practice of program skills. At pretest and posttest, children reported on parenting and parents reported child mental health. We hypothesized effects of quality on attendance, fidelity and attendance on home practice, and home practice on improvements in parenting and child mental health. Structural Equation Modeling with mediation and moderation analyses were used to test these associations. Results indicated quality was significantly associated with attendance, and attendance moderated the effect of fidelity on home practice. Home practice was a significant mediator of the links between fidelity and improvements in parent-child relationship quality and child externalizing and internalizing problems. Findings provide support for fidelity to the curriculum, process quality, attendance, and home practice as valid predictors of program outcomes for mothers and fathers. Future directions for assessing implementation in community settings are discussed.

On Multifunctional Collaborative Methods in Engineering Science

NASA Technical Reports Server (NTRS)

Ransom, Jonathan B.

2001-01-01

Multifunctional methodologies and analysis procedures are formulated for interfacing diverse subdomain idealizations including multi-fidelity modeling methods and multi-discipline analysis methods. These methods, based on the method of weighted residuals, ensure accurate compatibility of primary and secondary variables across the subdomain interfaces. Methods are developed using diverse mathematical modeling (i.e., finite difference and finite element methods) and multi-fidelity modeling among the subdomains. Several benchmark scalar-field and vector-field problems in engineering science are presented with extensions to multidisciplinary problems. Results for all problems presented are in overall good agreement with the exact analytical solution or the reference numerical solution. Based on the results, the integrated modeling approach using the finite element method for multi-fidelity discretization among the subdomains is identified as most robust. The multiple method approach is advantageous when interfacing diverse disciplines in which each of the method's strengths are utilized.

A High-Order, Time Invariant, Linearized Model for Application to HHCIAFCS Interaction Studies

NASA Technical Reports Server (NTRS)

Cheng, Rendy P.; Tischler, Mark B.; Celi, Roberto

2003-01-01

This paper describes a methodology for the extraction of a linear time invariant model from a nonlinear helicopter model, and followed by an examination of the interactions of the Higher Harmonic Control (HHC) and the Automatic Flight Control System (AFCS). This new method includes an embedded harmonic analyzer inside a linear time invariant model, which allows the periodicity of the helicopter response to be captured. The: coupled high-order model provides the needed level of dynamic fidelity to permit an analysis and optimization of the AFCS and HHC loops. Results of this study indicate that the closed-loop HHC system has little influence on the AFCS or on the vehicle handling qualities, which indicates that the AFCS does not need modification to work with the HHC system. The results also show that the vibration response to maneuvers must be considered during the HHC design process, which leads to much higher required HHC loop crossover frequencies. This research also demonstrates that the transient vibration response during maneuvers can be reduced by optimizing the closed-loop higher harmonic control laws using conventional control system analyses.

Tidal Energy Resource Assessment for McMurdo Station, Antarctica

DTIC Science & Technology

2016-12-01

highest power coefficient possible, only to provide a high- fidelity data set for a simple geometry turbine model at reasonably high blade chord Reynolds...highest power coefficient possible, only to provide a high-fidelity data set for a simple geometry turbine model at reasonably high blade chord...Reynolds numbers. Tip speed ratio, , is defined as = where is the anglular velocity of the blade and is the

Fidelity assessment of a UH-60A simulation on the NASA Ames vertical motion simulator

NASA Technical Reports Server (NTRS)

Atencio, Adolph, Jr.

1993-01-01

Helicopter handling qualities research requires that a ground-based simulation be a high-fidelity representation of the actual helicopter, especially over the frequency range of the investigation. This experiment was performed to assess the current capability to simulate the UH-60A Black Hawk helicopter on the Vertical Motion Simulator (VMS) at NASA Ames, to develop a methodology for assessing the fidelity of a simulation, and to find the causes for lack of fidelity. The approach used was to compare the simulation to the flight vehicle for a series of tasks performed in flight and in the simulator. The results show that subjective handling qualities ratings from flight to simulator overlap, and the mathematical model matches the UH-60A helicopter very well over the range of frequencies critical to handling qualities evaluation. Pilot comments, however, indicate a need for improvement in the perceptual fidelity of the simulation in the areas of motion and visual cuing. The methodology used to make the fidelity assessment proved useful in showing differences in pilot work load and strategy, but additional work is needed to refine objective methods for determining causes of lack of fidelity.

Solar Sail Spaceflight Simulation

NASA Technical Reports Server (NTRS)

Lisano, Michael; Evans, James; Ellis, Jordan; Schimmels, John; Roberts, Timothy; Rios-Reyes, Leonel; Scheeres, Daniel; Bladt, Jeff; Lawrence, Dale; Piggott, Scott

2007-01-01

The Solar Sail Spaceflight Simulation Software (S5) toolkit provides solar-sail designers with an integrated environment for designing optimal solar-sail trajectories, and then studying the attitude dynamics/control, navigation, and trajectory control/correction of sails during realistic mission simulations. Unique features include a high-fidelity solar radiation pressure model suitable for arbitrarily-shaped solar sails, a solar-sail trajectory optimizer, capability to develop solar-sail navigation filter simulations, solar-sail attitude control models, and solar-sail high-fidelity force models.

Low fidelity, high quality: a model for e-learning.

PubMed

Gordon, Morris; Chandratilake, Madawa; Baker, Paul

2013-08-01

E-learning continues to proliferate as a method to deliver continuing medical education. The effectiveness of e-learning has been widely studied, showing that it is as effective as traditional forms of education. However, most reports focus on whether the e-learning is effective, rather than discussing innovations to allow clinical educators to ask 'how' and 'why' it is effective, and to facilitate local reproduction. Previous work has set out a number of barriers to the introduction of e-learning interventions. Cost, the time to produce interventions, and the training requirements for educators and trainees have all been identified as barriers. We set out to design an e-learning intervention on paediatric prescribing that could address these issues using a low-fidelity approach, and report our methods so as to allow interested readers to use a similar approach. Using low-cost, readily accessible tools and applying appropriate educational theory, the intervention was produced in a short period of time. As part of a randomised controlled trial, long-term retention of prescribing skills was demonstrated, with significantly higher prescribing skill scores in the e-learning group at 4 and 12 weeks (p < 0.0001). Feedback was universally positive, with Likert responses suggesting that it was useful, convenient and easy to use. A low-fidelity approach to designing can successfully overcome many of the barriers to the introduction of e-learning. The design model described is simple and can be used by clinical teachers to support local development. Further research could investigate the experiences of these clinicians using this method of instructional design. © 2013 John Wiley & Sons Ltd.

Movements of four native Hawaiian birds across a naturally fragmented landscape

USGS Publications Warehouse

Knowlton, Jessie L.; Flaspohler, David J.; Paxton, Eben H.; Fukami, Tadashi; Giardina, Christian P.; Gruner, Daniel S.; Wilson Rankin, Erin E.

2017-01-01

Animals often increase their fitness by moving across space in response to temporal variation in habitat quality and resource availability, and as a result of intra and inter-specific interactions. The long-term persistence of populations and even whole species depends on the collective patterns of individual movements, yet animal movements have been poorly studied at the landscape level. We quantified movement behavior within four native species of Hawaiian forest birds in a complex lava-fragmented landscape: Hawai‛i ‘amakihi Chlorodrepanis virens, ‘oma‘o Myadestes obscurus, ‘apapane Himatione sanguinea, and ‘i‘iwi Drepanis coccinea. We evaluated the relative importance of six potential intrinsic and extrinsic drivers of movement behavior and patch fidelity: 1) forest fragment size, 2) the presence or absence of invasive rats (Rattus sp.), 3) season, 4) species, 5) age, and 6) sex. The study was conducted across a landscape of 34 forest fragments varying in size from 0.07 to 12.37 ha, of which 16 had rats removed using a treatment-control design. We found the largest movements in the nectivorous ‘apapane and ‘i‘iwi, intermediate levels in the generalist Hawai‛i ‘amakihi, and shortest average movement for the ‘oma‘o, a frugivore. We found evidence for larger patch sizes increasing patch fidelity only in the ‘oma‘o, and an effect of rat-removal increasing patch fidelity of Hawai‛i ‘amakihi only after two years of rat-removal. Greater movement during the non-breeding season was observed in all species, and season was an important factor in explaining higher patch fidelity in the breeding season for ‘apapane and ‘i‘iwi. Sex was important in explaining patch fidelity in ‘oma‘o only, with males showing higher patch fidelity. Our results provide new insights into how these native Hawaiian species will respond to a changing environment, including habitat fragmentation and changing distribution of threats from climate change.

Controlling the transmitted information of a multi-photon interacting with a single-Cooper pair box

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadry, Heba, E-mail: hkadry1@yahoo.com; Abdel-Aty, Abdel-Haleem, E-mail: hkadry1@yahoo.com; Zakaria, Nordin, E-mail: hkadry1@yahoo.com

2014-10-24

We study a model of a multi-photon interaction of a single Cooper pair box with a cavity field. The exchange of the information using this system is studied. We quantify the fidelity of the transmitted information. The effect of the system parameters (detuning parameter, field photons, state density and mean photon number) in the fidelity of the transmitted information is investigated. We found that the fidelity of the transmitted information can be controlled using the system parameters.

Three-dimensional brain arteriovenous malformation models for clinical use and resident training.

PubMed

Dong, Mengqi; Chen, Guangzhong; Li, Jianyi; Qin, Kun; Ding, Xiaowen; Peng, Chao; Zhou, Dong; Lin, Xiaofeng

2018-01-01

To fabricate three-dimensional (3D) models of brain arteriovenous malformation (bAVM) and report our experience with customized 3D printed models of patients with bAVM as an educational and clinical tool for patients, doctors, and surgical residents. Using computerized tomography angiography (CTA) or digital subtraction angiography (DSA) images, the rapid prototyping process was completed with specialized software and "in-house" 3D printing service. Intraoperative validation of model fidelity was performed by comparing to DSA images of the same patient during the endovascular treatment process. 3D bAVM models were used for preoperative patient education and consultation, surgical planning, and resident training. 3D printed bAVM models were successful made. By neurosurgeons' evaluation, the printed models precisely replicated the actual bAVM structure of the same patients (n = 7, 97% concordance, range 95%-99% with average of < 2 mm variation). The use of 3D models was associated shorter time for preoperative patient education and consultation, higher acceptable of the procedure for patients and relatives, shorter time between obtaining intraoperative DSA data and the start of endovascular treatment. Thirty surgical residents from residency programs tested the bAVM models and provided feedback on their resemblance to real bAVM structures and the usefulness of printed solid model as an educational tool. Patient-specific 3D printed models of bAVM can be constructed with high fidelity. 3D printed bAVM models were proven to be helpful in preoperative patient consultation, surgical planning, and resident training. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Promoting Afterschool Quality and Positive Youth Development: Cluster Randomized Trial of the Pax Good Behavior Game.

PubMed

Smith, Emilie Phillips; Osgood, D Wayne; Oh, Yoonkyung; Caldwell, Linda C

2018-02-01

This randomized trial tested a strategy originally developed for school settings, the Pax Good Behavior Game (PAX GBG), in the new context of afterschool programs. We examined this approach in afterschool since 70% of all juvenile crime occurs between the hours of 3-6 pm, making afterschool an important setting for prevention and promotion. Dual-career and working families need monitoring and supervision for their children in quality settings that are safe and appropriately structured. While substantial work has identified important features of afterschool programs, increasing attention is being given to how to foster quality. PAX GBG, with its focus on shared norms, cooperative teams, contingent activity rewards, and liberal praise, could potentially enhance not only appropriate structure and supportive relationships, but also youth self-regulation, co-regulation, and socio-emotional development. This study examined the PAX GBG among 76 afterschool programs, serving 811 youth ages 5-12, who were diverse in race-ethnicity, socio-economic status, and geographic locale. Demographically matched pairs of afterschool programs were randomized to PAX GBG or treatment-as-usual. Independent observers conducted ratings of implementation fidelity and program quality across time; along with surveys of children's problem and prosocial behavior. Interaction effects were found using hierarchical linear models such that experimental programs evidencing higher implementation fidelity demonstrated better program quality than controls, (i.e., less harshness, increased appropriate structure, support, and engagement), as well as reduced child-reported hyperactivity and intent-to-treat effects on prosocial behavior. This study demonstrates that best practices fostered by PAX GBG and implemented with fidelity in afterschool result in higher quality contexts for positive youth development.

Biochemical analysis of DNA polymerase η fidelity in the presence of replication protein A.

PubMed

Suarez, Samuel C; Toffton, Shannon M; McCulloch, Scott D

2014-01-01

DNA polymerase η (pol η) synthesizes across from damaged DNA templates in order to prevent deleterious consequences like replication fork collapse and double-strand breaks. This process, termed translesion synthesis (TLS), is an overall positive for the cell, as cells deficient in pol η display higher mutation rates. This outcome occurs despite the fact that the in vitro fidelity of bypass by pol η alone is moderate to low, depending on the lesion being copied. One possible means of increasing the fidelity of pol η is interaction with replication accessory proteins present at the replication fork. We have previously utilized a bacteriophage based screening system to measure the fidelity of bypass using purified proteins. Here we report on the fidelity effects of a single stranded binding protein, replication protein A (RPA), when copying the oxidative lesion 7,8-dihydro-8-oxo-guanine(8-oxoG) and the UV-induced cis-syn thymine-thymine cyclobutane pyrimidine dimer (T-T CPD). We observed no change in fidelity dependent on RPA when copying these damaged templates. This result is consistent in multiple position contexts. We previously identified single amino acid substitution mutants of pol η that have specific effects on fidelity when copying both damaged and undamaged templates. In order to confirm our results, we examined the Q38A and Y52E mutants in the same full-length construct. We again observed no difference when RPA was added to the bypass reaction, with the mutant forms of pol η displaying similar fidelity regardless of RPA status. We do, however, observe some slight effects when copying undamaged DNA, similar to those we have described previously. Our results indicate that RPA by itself does not affect pol η dependent lesion bypass fidelity when copying either 8-oxoG or T-T CPD lesions.

Roseate Tern breeding dispersal and fidelity: Responses to two newly restored colony sites

USGS Publications Warehouse

Spendelow, Jeffrey A.; Monticelli, David; Nichols, James D.; Hines, James; Nisbet, Ian; Cormons, Grace; Hays, Helen; Hatch, Jeremy; Mostello, Carolyn

2016-01-01

We used 22 yr of capture–mark–reencounter (CMR) data collected from 1988 to 2009 on about 12,500 birds at what went from three to five coastal colony sites in Massachusetts, New York, and Connecticut, United States, to examine spatial and temporal variation in breeding dispersal/fidelity rates of adult Roseate Terns (Sterna dougallii). At the start of our study, Roseate Terns nested at only one site (Bird Island) in Buzzards Bay, Massachusetts, but two more sites in this bay (Ram and Penikese Islands) were subsequently recolonized and became incorporated into our CMR metapopulation study. We examined four major hypotheses about factors we thought might influence colony-site fidelity and movement rates in the restructured system. We found some evidence that colony-site fidelity remained higher at long-established sites compared with newer ones and that breeding dispersal was more likely to occur among nearby sites than distant ones. Sustained predation at Falkner Island, Connecticut, did not result in a sustained drop in fidelity rates of breeders. Patterns of breeding dispersal differed substantially at the two restored sites. The fidelity of Roseate Terns at Bird dropped quickly after nearby Ram was recolonized in 1994, and fidelity rates for Ram soon approached those for Bird. After an oil spill in Buzzards Bay in April 2003, hazing (deliberate disturbance) of the terns at Ram prior to the start of egg-laying resulted in lowering of fidelity at this site, a decrease in immigration from Bird, and recolonization of Penikese by Roseate Terns. Annual fidelity rates at Penikese increased somewhat several years after the initial recolonization, but they remained much lower there than at all the other sites throughout the study period. The sustained high annual rates of emigration from Penikese resulted in the eventual failure of the restoration effort there, and in 2013, no Roseate Terns nested at this site.

Implementation of a Smeared Crack Band Model in a Micromechanics Framework

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Bednarcyk, Brett A.; Waas, Anthony M.; Arnold, Steven M.

2012-01-01

The smeared crack band theory is implemented within the generalized method of cells and high-fidelity generalized method of cells micromechanics models to capture progressive failure within the constituents of a composite material while retaining objectivity with respect to the size of the discretization elements used in the model. An repeating unit cell containing 13 randomly arranged fibers is modeled and subjected to a combination of transverse tension/compression and transverse shear loading. The implementation is verified against experimental data (where available), and an equivalent finite element model utilizing the same implementation of the crack band theory. To evaluate the performance of the crack band theory within a repeating unit cell that is more amenable to a multiscale implementation, a single fiber is modeled with generalized method of cells and high-fidelity generalized method of cells using a relatively coarse subcell mesh which is subjected to the same loading scenarios as the multiple fiber repeating unit cell. The generalized method of cells and high-fidelity generalized method of cells models are validated against a very refined finite element model.

Modeling and Simulation of Phased Array Antennas to Support Next-Generation Satellite Design

NASA Technical Reports Server (NTRS)

Tchorowski, Nicole; Murawski, Robert; Manning, Robert; Fuentes, Michael

2016-01-01

Developing enhanced simulation capabilities has become a significant priority for the Space Communications and Navigation (SCaN) project at NASA as new space communications technologies are proposed to replace aging NASA communications assets, such as the Tracking and Data Relay Satellite System (TDRSS). When developing the architecture for these new space communications assets, it is important to develop updated modeling and simulation methodologies, such that competing architectures can be weighed against one another and the optimal path forward can be determined. There have been many simulation tools developed here at NASA for the simulation of single RF link budgets, or for the modeling and simulation of an entire network of spacecraft and their supporting SCaN network elements. However, the modeling capabilities are never fully complete and as new technologies are proposed, gaps are identified. One such gap is the ability to rapidly develop high fidelity simulation models of electronically steerable phased array systems. As future relay satellite architectures are proposed that include optical communications links, electronically steerable antennas will become more desirable due to the reduction in platform vibration introduced by mechanically steerable devices. In this research, we investigate how modeling of these antennas can be introduced into out overall simulation and modeling structure. The ultimate goal of this research is two-fold. First, to enable NASA engineers to model various proposed simulation architectures and determine which proposed architecture meets the given architectural requirements. Second, given a set of communications link requirements for a proposed satellite architecture, determine the optimal configuration for a phased array antenna. There is a variety of tools available that can be used to model phased array antennas. To meet our stated goals, the first objective of this research is to compare the subset of tools available to us, trading-off modeling fidelity of the tool with simulation performance. When comparing several proposed architectures, higher- fidelity modeling may be desirable, however, when iterating a proposed set of communication link requirements across ranges of phased array configuration parameters, the practicality of performance becomes a significant requirement. In either case, a minimum simulation - fidelity must be met, regardless of performance considerations, which will be discussed in this research. Given a suitable set of phased array modeling tools, this research then focuses on integration with current SCaN modeling and simulation tools. While properly modeling the antenna elements of a system are vital, this is only a small part of the end-to-end communication path between a satellite and the supporting ground station and/or relay satellite assets. To properly model a proposed simulation architecture, this toolset must be integrated with other commercial and government development tools, such that the overall architecture can be examined in terms of communications, reliability, and cost. In this research, integration with previously developed communication tools is investigated.

Autonomous Aerobraking: Thermal Analysis and Response Surface Development

NASA Technical Reports Server (NTRS)

Dec, John A.; Thornblom, Mark N.

2011-01-01

A high-fidelity thermal model of the Mars Reconnaissance Orbiter was developed for use in an autonomous aerobraking simulation study. Response surface equations were derived from the high-fidelity thermal model and integrated into the autonomous aerobraking simulation software. The high-fidelity thermal model was developed using the Thermal Desktop software and used in all phases of the analysis. The use of Thermal Desktop exclusively, represented a change from previously developed aerobraking thermal analysis methodologies. Comparisons were made between the Thermal Desktop solutions and those developed for the previous aerobraking thermal analyses performed on the Mars Reconnaissance Orbiter during aerobraking operations. A variable sensitivity screening study was performed to reduce the number of variables carried in the response surface equations. Thermal analysis and response surface equation development were performed for autonomous aerobraking missions at Mars and Venus.

Development of high-fidelity multiphysics system for light water reactor analysis

NASA Astrophysics Data System (ADS)

Magedanz, Jeffrey W.

There has been a tendency in recent years toward greater heterogeneity in reactor cores, due to the use of mixed-oxide (MOX) fuel, burnable absorbers, and longer cycles with consequently higher fuel burnup. The resulting asymmetry of the neutron flux and energy spectrum between regions with different compositions causes a need to account for the directional dependence of the neutron flux, instead of the traditional diffusion approximation. Furthermore, the presence of both MOX and high-burnup fuel in the core increases the complexity of the heat conduction. The heat transfer properties of the fuel pellet change with irradiation, and the thermal and mechanical expansion of the pellet and cladding strongly affect the size of the gap between them, and its consequent thermal resistance. These operational tendencies require higher fidelity multi-physics modeling capabilities, and this need is addressed by the developments performed within this PhD research. The dissertation describes the development of a High-Fidelity Multi-Physics System for Light Water Reactor Analysis. It consists of three coupled codes -- CTF for Thermal Hydraulics, TORT-TD for Neutron Kinetics, and FRAPTRAN for Fuel Performance. It is meant to address these modeling challenges in three ways: (1) by resolving the state of the system at the level of each fuel pin, rather than homogenizing entire fuel assemblies, (2) by using the multi-group Discrete Ordinates method to account for the directional dependence of the neutron flux, and (3) by using a fuel-performance code, rather than a Thermal Hydraulics code's simplified fuel model, to account for the material behavior of the fuel and its feedback to the hydraulic and neutronic behavior of the system. While the first two are improvements, the third, the use of a fuel-performance code for feedback, constitutes an innovation in this PhD project. Also important to this work is the manner in which such coupling is written. While coupling involves combining codes into a single executable, they are usually still developed and maintained separately. It should thus be a design objective to minimize the changes to those codes, and keep the changes to each code free of dependence on the details of the other codes. This will ease the incorporation of new versions of the code into the coupling, as well as re-use of parts of the coupling to couple with different codes. In order to fulfill this objective, an interface for each code was created in the form of an object-oriented abstract data type. Object-oriented programming is an effective method for enforcing a separation between different parts of a program, and clarifying the communication between them. The interfaces enable the main program to control the codes in terms of high-level functionality. This differs from the established practice of a master/slave relationship, in which the slave code is incorporated into the master code as a set of subroutines. While this PhD research continues previous work with a coupling between CTF and TORT-TD, it makes two major original contributions: (1) using a fuel-performance code, instead of a thermal-hydraulics code's simplified built-in models, to model the feedback from the fuel rods, and (2) the design of an object-oriented interface as an innovative method to interact with a coupled code in a high-level, easily-understandable manner. The resulting code system will serve as a tool to study the question of under what conditions, and to what extent, these higher-fidelity methods will provide benefits to reactor core analysis. (Abstract shortened by UMI.)

The efficacy of high-fidelity simulation on psychomotor clinical performance improvement of undergraduate nursing students.

PubMed

Vincent, Mary Anne; Sheriff, Susan; Mellott, Susan

2015-02-01

High-fidelity simulation has become a growing educational modality among institutions of higher learning ever since the Institute of Medicine recommended that it be used to improve patient safety in 2000. However, there is limited research on the effect of high-fidelity simulation on psychomotor clinical performance improvement of undergraduate nursing students being evaluated by experts using reliable and valid appraisal instruments. The purpose of this integrative review and meta-analysis is to explore what researchers have established about the impact of high-fidelity simulation on improving the psychomotor clinical performance of undergraduate nursing students. Only eight of the 1120 references met inclusion criteria. A meta-analysis using Hedges' g to compute the effect size and direction of impact yielded a range of -0.26 to +3.39. A positive effect was shown in seven of eight studies; however, there were five different research designs and six unique appraisal instruments used among these studies. More research is necessary to determine if high-fidelity simulation improves psychomotor clinical performance in undergraduate nursing students. Nursing programs from multiple sites having a standardized curriculum and using the same appraisal instruments with established reliability and validity are ideal for this work.

F-14 modeling study

NASA Technical Reports Server (NTRS)

Levison, William H.

1988-01-01

This study explored application of a closed loop pilot/simulator model to the analysis of some simulator fidelity issues. The model was applied to two data bases: (1) a NASA ground based simulation of an air-to-air tracking task in which nonvisual cueing devices were explored, and (2) a ground based and inflight study performed by the Calspan Corporation to explore the effects of simulator delay on attitude tracking performance. The model predicted the major performance trends obtained in both studies. A combined analytical and experimental procedure for exploring simulator fidelity issues is outlined.

Development of Ku-band rendezvous radar tracking and acquisition simulation programs

NASA Technical Reports Server (NTRS)

1986-01-01

The fidelity of the Space Shuttle Radar tracking simulation model was improved. The data from the Shuttle Orbiter Radar Test and Evaluation (SORTE) program experiments performed at the White Sands Missile Range (WSMR) were reviewed and analyzed. The selected flight rendezvous radar data was evaluated. Problems with the Inertial Line-of-Sight (ILOS) angle rate tracker were evaluated using the improved fidelity angle rate tracker simulation model.

Aerodynamic Simulation of Ice Accretion on Airfoils

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Addy, Harold E., Jr.; Bragg, Michael B.; Busch, Greg T.; Montreuil, Emmanuel

2011-01-01

This report describes recent improvements in aerodynamic scaling and simulation of ice accretion on airfoils. Ice accretions were classified into four types on the basis of aerodynamic effects: roughness, horn, streamwise, and spanwise ridge. The NASA Icing Research Tunnel (IRT) was used to generate ice accretions within these four types using both subscale and full-scale models. Large-scale, pressurized windtunnel testing was performed using a 72-in.- (1.83-m-) chord, NACA 23012 airfoil model with high-fidelity, three-dimensional castings of the IRT ice accretions. Performance data were recorded over Reynolds numbers from 4.5 x 10(exp 6) to 15.9 x 10(exp 6) and Mach numbers from 0.10 to 0.28. Lower fidelity ice-accretion simulation methods were developed and tested on an 18-in.- (0.46-m-) chord NACA 23012 airfoil model in a small-scale wind tunnel at a lower Reynolds number. The aerodynamic accuracy of the lower fidelity, subscale ice simulations was validated against the full-scale results for a factor of 4 reduction in model scale and a factor of 8 reduction in Reynolds number. This research has defined the level of geometric fidelity required for artificial ice shapes to yield aerodynamic performance results to within a known level of uncertainty and has culminated in a proposed methodology for subscale iced-airfoil aerodynamic simulation.

Measuring Implementation Fidelity in a Community-Based Parenting Intervention

PubMed Central

Breitenstein, Susan M.; Fogg, Louis; Garvey, Christine; Hill, Carri; Resnick, Barbara; Gross, Deborah

2012-01-01

Background Establishing the feasibility and validity of implementation fidelity monitoring strategies is an important methodological step in implementing evidence-based interventions on a large scale. Objectives The objective of the study was to examine the reliability and validity of the Fidelity Checklist, a measure designed to assess group leader adherence and competence delivering a parent training intervention (the Chicago Parent Program) in child care centers serving low-income families. Method The sample included 9 parent groups (12 group sessions each), 12 group leaders, and 103 parents. Independent raters reviewed 106 audiotaped parent group sessions and coded group leaders’ fidelity on the Adherence and Competence Scales of the Fidelity Checklist. Group leaders completed self-report adherence checklists and a measure of parent engagement in the intervention. Parents completed measures of consumer satisfaction and child behavior. Results High interrater agreement (Adherence Scale = 94%, Competence Scale = 85%) and adequate intraclass correlation coefficients (Adherence Scale = .69, Competence Scale = .91) were achieved for the Fidelity Checklist. Group leader adherence changed over time, but competence remained stable. Agreement between group leader self-report and independent ratings on the Adherence Scale was 85%; disagreements were more frequently due to positive bias in group leader self-report. Positive correlations were found between group leader adherence and parent attendance and engagement in the intervention and between group leader competence and parent satisfaction. Although child behavior problems improved, improvements were not related to fidelity. Discussion The results suggest that the Fidelity Checklist is a feasible, reliable, and valid measure of group leader implementation fidelity in a group-based parenting intervention. Future research will be focused on testing the Fidelity Checklist with diverse and larger samples and generalizing to other group-based interventions using a similar intervention model. PMID:20404777

Assessing intervention fidelity in a multi-level, multi-component, multi-site program: the Children's Healthy Living (CHL) program.

PubMed

Butel, Jean; Braun, Kathryn L; Novotny, Rachel; Acosta, Mark; Castro, Rose; Fleming, Travis; Powers, Julianne; Nigg, Claudio R

2015-12-01

Addressing complex chronic disease prevention, like childhood obesity, requires a multi-level, multi-component culturally relevant approach with broad reach. Models are lacking to guide fidelity monitoring across multiple levels, components, and sites engaged in such interventions. The aim of this study is to describe the fidelity-monitoring approach of The Children's Healthy Living (CHL) Program, a multi-level multi-component intervention in five Pacific jurisdictions. A fidelity-monitoring rubric was developed. About halfway during the intervention, community partners were randomly selected and interviewed independently by local CHL staff and by Coordinating Center representatives to assess treatment fidelity. Ratings were compared and discussed by local and Coordinating Center staff. There was good agreement between the teams (Kappa = 0.50, p < 0.001), and intervention improvement opportunities were identified through data review and group discussion. Fidelity for the multi-level, multi-component, multi-site CHL intervention was successfully assessed, identifying adaptations as well as ways to improve intervention delivery prior to the end of the intervention.

Peridynamic Theory as a New Paradigm for Multiscale Modeling of Sintering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silling, Stewart A.; Abdeljawad, Fadi; Ford, Kurtis Ross

2017-09-01

Sintering is a component fabrication process in which powder is compacted by pressing or some other means and then held at elevated temperature for a period of hours. The powder grains bond with each other, leading to the formation of a solid component with much lower porosity, and therefore higher density and higher strength, than the original powder compact. In this project, we investigated a new way of computationally modeling sintering at the length scale of grains. The model uses a high-fidelity, three-dimensional representation with a few hundred nodes per grain. The numerical model solves the peridynamic equations, in whichmore » nonlocal forces allow representation of the attraction, adhesion, and mass diffusion between grains. The deformation of the grains is represented through a viscoelastic material model. The project successfully demonstrated the use of this method to reproduce experimentally observed features of material behavior in sintering, including densification, the evolution of microstructure, and the occurrence of random defects in the sintered solid.« less

Progressive Failure of a Unidirectional Fiber-Reinforced Composite Using the Method of Cells: Discretization Objective Computational Results

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Bednarcyk, Brett A.; Waas, Anthony M.; Arnold, Steven M.

2012-01-01

The smeared crack band theory is implemented within the generalized method of cells and high-fidelity generalized method of cells micromechanics models to capture progressive failure within the constituents of a composite material while retaining objectivity with respect to the size of the discretization elements used in the model. An repeating unit cell containing 13 randomly arranged fibers is modeled and subjected to a combination of transverse tension/compression and transverse shear loading. The implementation is verified against experimental data (where available), and an equivalent finite element model utilizing the same implementation of the crack band theory. To evaluate the performance of the crack band theory within a repeating unit cell that is more amenable to a multiscale implementation, a single fiber is modeled with generalized method of cells and high-fidelity generalized method of cells using a relatively coarse subcell mesh which is subjected to the same loading scenarios as the multiple fiber repeating unit cell. The generalized method of cells and high-fidelity generalized method of cells models are validated against a very refined finite element model.

Survival, site and mate fidelity in south polar skuas Catharacta maccormicki at Anvers Island, Antarctica

USGS Publications Warehouse

Pietz, P.J.; Parmelee, D.F.

1993-01-01

In 1974-1975, 34 adult South Polar Skuas Catharacta maccormicki were colour-ringed on 18 nest territories at Bonaparte Point, Anvers Island, near Palmer Station along the Antarctic Peninsula. Subsequently, the area was searched for these birds during the austral summers of 1975-1976 to 1984-1985 and in 1987-1988 and 1989-1990. Fifty-three percent were seen in 1984-1985, 32% in 1987-1988 and 21% in 1989-1990. Annual survival rate averaged 95% from 1974-1975 to 1984-1985; no sexual differences were detected (n = 28 of known sex). Strong territory and mate fidelity were apparent; 34 skuas averaged 1.1 nest territories and 1.7 mates each in 16 years. Only 4 of 34 individuals (all females) were known to change territories, and each territory change involved a change of mates. Although males showed higher territory fidelity than females (P < 0.01), most females (four of five) retained their territories when previous mates failed to return. Seventeen of 34 birds changed mates a total of 24 times; at least 20 mate changes followed the death or disappearance of the former mate. Males showed slightly higher mate fidelity than females (P < 0.04). Female South Polar and Brown Skuas Catharacta lonnbergi did not differ in territory or mate fidelity. From 1974-1975 to 1984-1985, 120 South Polar Skua chicks were ringed on 18 nest territories on Bonaparte Point; 17 were resighted in the Palmer area when they were 3-10 years old. All 17 returnees were found within 3 km of their natal nest sites, and four of them occupied nest territories on Bonaparte Point.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, D.R.; Hutchinson, J.L.

Eagle 11 is a prototype analytic model derived from the integration of the low resolution Eagle model with the high resolution SIMNET model. This integration promises a new capability to allow for a more effective examination of proposed or existing combat systems that could not be easily evaluated using either Eagle or SIMNET alone. In essence, Eagle II becomes a multi-resolution combat model in which simulated combat units can exhibit both high and low fidelity behavior at different times during model execution. This capability allows a unit to behave in a highly manner only when required, thereby reducing the overallmore » computational and manpower requirements for a given study. In this framework, the SIMNET portion enables a highly credible assessment of the performance of individual combat systems under consideration, encompassing both engineering performance and crew capabilities. However, when the assessment being conducted goes beyond system performance and extends to questions of force structure balance and sustainment, then SISMNET results can be used to ``calibrate`` the Eagle attrition process appropriate to the study at hand. Advancing technologies, changes in the world-wide threat, requirements for flexible response, declining defense budgets, and down-sizing of military forces motivate the development of manpower-efficient, low-cost, responsive tools for combat development studies. Eagle and SIMNET both serve as credible and useful tools. The integration of these two models promises enhanced capabilities to examine the broader, deeper, more complex battlefield of the future with higher fidelity, greater responsiveness and low overall cost.« less

Development of a Higher Fidelity Model for the Cascade Distillation Subsystem (CDS)

NASA Technical Reports Server (NTRS)

Perry, Bruce; Anderson, Molly

2014-01-01

Significant improvements have been made to the ACM model of the CDS, enabling accurate predictions of dynamic operations with fewer assumptions. The model has been utilized to predict how CDS performance would be impacted by changing operating parameters, revealing performance trade-offs and possibilities for improvement. CDS efficiency is driven by the THP coefficient of performance, which in turn is dependent on heat transfer within the system. Based on the remaining limitations of the simulation, priorities for further model development include: center dot Relaxing the assumption of total condensation center dot Incorporating dynamic simulation capability for the buildup of dissolved inert gasses in condensers center dot Examining CDS operation with more complex feeds center dot Extending heat transfer analysis to all surfaces

Probabilistic Fatigue Damage Prognosis Using a Surrogate Model Trained Via 3D Finite Element Analysis

NASA Technical Reports Server (NTRS)

Leser, Patrick E.; Hochhalter, Jacob D.; Newman, John A.; Leser, William P.; Warner, James E.; Wawrzynek, Paul A.; Yuan, Fuh-Gwo

2015-01-01

Utilizing inverse uncertainty quantification techniques, structural health monitoring can be integrated with damage progression models to form probabilistic predictions of a structure's remaining useful life. However, damage evolution in realistic structures is physically complex. Accurately representing this behavior requires high-fidelity models which are typically computationally prohibitive. In the present work, a high-fidelity finite element model is represented by a surrogate model, reducing computation times. The new approach is used with damage diagnosis data to form a probabilistic prediction of remaining useful life for a test specimen under mixed-mode conditions.

A high-fidelity airbus benchmark for system fault detection and isolation and flight control law clearance

NASA Astrophysics Data System (ADS)

Goupil, Ph.; Puyou, G.

2013-12-01

This paper presents a high-fidelity generic twin engine civil aircraft model developed by Airbus for advanced flight control system research. The main features of this benchmark are described to make the reader aware of the model complexity and representativeness. It is a complete representation including the nonlinear rigid-body aircraft model with a full set of control surfaces, actuator models, sensor models, flight control laws (FCL), and pilot inputs. Two applications of this benchmark in the framework of European projects are presented: FCL clearance using optimization and advanced fault detection and diagnosis (FDD).

Validation of NASCAP-2K Spacecraft-Environment Interactions Calculations

NASA Technical Reports Server (NTRS)

Davis, V. A.; Mandell, M. J.; Gardner, B. M.; Mikellides, I. G.; Neergaard, L. F.; Cooke, D. L.; Minor, J.

2004-01-01

The recently released Nascap-2k, version 2.0, three-dimensional computer code models interactions between spacecraft surfaces and low-earth-orbit, geosynchronous, auroral, and interplanetary plasma environments. It replaces the earlier three-dimensional spacecraft interactions codes NASCAP/GEO, NASCAP/LEO, POLAR, and DynaPAC. Nascap-2k has improved numeric techniques, a modern user interface, and a simple, interactive satellite surface definition module (Object ToolKit). We establish the accuracy of Nascap-2k both by comparing computed currents and potentials with analytic results and by comparing Nascap-2k results with published calculations using the earlier codes. Nascap-2k predicts Langmuir-Blodgett or Parker-Murphy current collection for a nearly spherical (100 surfaces) satellite in a short Debye length plasma depending on the absence or presence of a magnetic field. A low fidelity (in geometry and time) Nascap-2k geosynchronous charging calculation gives the same results as the corresponding low fidelity NASCAP/GEO calculation. A high fidelity calculation (using the Nascap-2k improved geometry and time stepping capabilities) gives higher potentials, which are more consistent with typical observations. Nascap-2k predicts the same current as a function of applied potential as was observed and calculated by NASCAP/LEO for the SPEAR I rocket with a bipolar sheath. A Nascap-2k DMSP charging calculation gives results similar to those obtained using POLAR and consistent with observation.

High-Fidelity Roadway Modeling and Simulation

NASA Technical Reports Server (NTRS)

Wang, Jie; Papelis, Yiannis; Shen, Yuzhong; Unal, Ozhan; Cetin, Mecit

2010-01-01

Roads are an essential feature in our daily lives. With the advances in computing technologies, 2D and 3D road models are employed in many applications, such as computer games and virtual environments. Traditional road models were generated by professional artists manually using modeling software tools such as Maya and 3ds Max. This approach requires both highly specialized and sophisticated skills and massive manual labor. Automatic road generation based on procedural modeling can create road models using specially designed computer algorithms or procedures, reducing the tedious manual editing needed for road modeling dramatically. But most existing procedural modeling methods for road generation put emphasis on the visual effects of the generated roads, not the geometrical and architectural fidelity. This limitation seriously restricts the applicability of the generated road models. To address this problem, this paper proposes a high-fidelity roadway generation method that takes into account road design principles practiced by civil engineering professionals, and as a result, the generated roads can support not only general applications such as games and simulations in which roads are used as 3D assets, but also demanding civil engineering applications, which requires accurate geometrical models of roads. The inputs to the proposed method include road specifications, civil engineering road design rules, terrain information, and surrounding environment. Then the proposed method generates in real time 3D roads that have both high visual and geometrical fidelities. This paper discusses in details the procedures that convert 2D roads specified in shape files into 3D roads and civil engineering road design principles. The proposed method can be used in many applications that have stringent requirements on high precision 3D models, such as driving simulations and road design prototyping. Preliminary results demonstrate the effectiveness of the proposed method.

Intervention Fidelity in Family-Based Prevention Counseling for Adolescent Problem Behaviors

ERIC Educational Resources Information Center

Hogue, Aaron; Liddle, Howard A.; Singer, Alisa; Leckrone, Jodi

2005-01-01

This study examined fidelity in multidimensional family prevention (MDFP), a family-based prevention counseling model for adolescents at high risk for substance abuse and related behavior problems, in comparison to two empirically based treatments for adolescent drug abuse: multidimensional family therapy (MDFT) and cognitive-behavioral therapy…

A "Common Factors" Approach to Developing Culturally Tailored HIV Prevention Interventions

ERIC Educational Resources Information Center

Owczarzak, Jill; Phillips, Sarah D.; Filippova, Olga; Alpatova, Polina; Mazhnaya, Alyona; Zub, Tatyana; Aleksanyan, Ruzanna

2016-01-01

The current dominant model of HIV prevention intervention dissemination involves packaging interventions developed in one context, training providers to implement that specific intervention, and evaluating the extent to which providers implement it with fidelity. Research shows that providers rarely implement these programs with fidelity due to…

ARC integration into the NEAMS Workbench

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stauff, N.; Gaughan, N.; Kim, T.

2017-01-01

One of the objectives of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Integration Product Line (IPL) is to facilitate the deployment of the high-fidelity codes developed within the program. The Workbench initiative was launched in FY-2017 by the IPL to facilitate the transition from conventional tools to high fidelity tools. The Workbench provides a common user interface for model creation, real-time validation, execution, output processing, and visualization for integrated codes.

Adolescent and parent motivation for change affects psychotherapy outcomes among youth with poorly controlled diabetes.

PubMed

Ellis, Deborah A; Berio, Heidi; Carcone, April Idalski; Naar-King, Sylvie

2012-01-01

Investigate effect of baseline motivation for change on treatment fidelity, therapeutic alliance, treatment dose, and treatment outcome in a randomized controlled trial of family therapy for youth with poorly controlled diabetes. Seventy-four adolescents and caregivers completed measures of motivation for change. Measures of fidelity, alliance, dose, and youth health status were collected. Structural equation modeling was used to test the direct and indirect effects of motivation on treatment outcomes. Parent motivation was significantly related to alliance and fidelity. Only alliance was significantly related to posttreatment metabolic control. In adolescent models, only motivation was significantly related to alliance. In both models, motivation had a significant indirect effect on metabolic control through alliance. Findings demonstrate the importance of parent and youth initial motivational status and treatment alliance to treatment outcome among youth with poorly controlled diabetes. Additional research on treatment techniques that promote motivation for change is needed.

Vertical structure and physical processes of the Madden-Julian oscillation: Linking hindcast fidelity to simulated diabatic heating and moistening

DOE PAGES

Klingaman, Nicholas P.; Woolnough, Steven J.; Jiang, Xianan; ...

2015-04-10

Here, many theories for the Madden-Julian oscillation (MJO) focus on diabatic processes, particularly the evolution of vertical heating and moistening. Poor MJO performance in weather and climate models is often blamed on biases in these processes and their interactions with the large-scale circulation. We introduce one of the three components of a model evaluation project, which aims to connect MJO fidelity in models to their representations of several physical processes, focusing on diabatic heating and moistening. This component consists of 20 day hindcasts, initialized daily during two MJO events in winter 2009–2010. The 13 models exhibit a range of skill:more » several have accurate forecasts to 20 days lead, while others perform similarly to statistical models (8–11 days). Models that maintain the observed MJO amplitude accurately predict propagation, but not vice versa. We find no link between hindcast fidelity and the precipitation-moisture relationship, in contrast to other recent studies. There is also no relationship between models' performance and the evolution of their diabatic heating profiles with rain rate. A more robust association emerges between models' fidelity and net moistening: the highest-skill models show a clear transition from low-level moistening for light rainfall to midlevel moistening at moderate rainfall and upper level moistening for heavy rainfall. The midlevel moistening, arising from both dynamics and physics, may be most important. Accurately representing many processes may be necessary but not sufficient for capturing the MJO, which suggests that models fail to predict the MJO for a broad range of reasons and limits the possibility of finding a panacea.« less

Benefits to the Simulation Training Community of a New ANSI Standard for the Exchange of Aero Simulation Models

NASA Technical Reports Server (NTRS)

Hildreth, Bruce L.; Jackson, E. Bruce

2009-01-01

The American Institute of Aeronautics Astronautics (AIAA) Modeling and Simulation Technical Committee is in final preparation of a new standard for the exchange of flight dynamics models. The standard will become an ANSI standard and is under consideration for submission to ISO for acceptance by the international community. The standard has some a spects that should provide benefits to the simulation training community. Use of the new standard by the training simulation community will reduce development, maintenance and technical refresh investment on each device. Furthermore, it will significantly lower the cost of performing model updates to improve fidelity or expand the envelope of the training device. Higher flight fidelity should result in better transfer of training, a direct benefit to the pilots under instruction. Costs of adopting the standard are minimal and should be paid back within the cost of the first use for that training device. The standard achie ves these advantages by making it easier to update the aerodynamic model. It provides a standard format for the model in a custom eXtensible Markup Language (XML) grammar, the Dynamic Aerospace Vehicle Exchange Markup Language (DAVE-ML). It employs an existing XML grammar, MathML, to describe the aerodynamic model in an input data file, eliminating the requirement for actual software compilation. The major components of the aero model become simply an input data file, and updates are simply new XML input files. It includes naming and axis system conventions to further simplify the exchange of information.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demkowicz-Dobrzanski, Rafal; Lewenstein, Maciej; Institut fuer Theoretische Physik, Universitaet Hannover, D-30167 Hannover

We solve the problem of the optimal cloning of pure entangled two-qubit states with a fixed degree of entanglement using local operations and classical communication. We show that, amazingly, classical communication between the parties can improve the fidelity of local cloning if and only if the initial entanglement is higher than a certain critical value. It is completely useless for weakly entangled states. We also show that bound entangled states with positive partial transpose are not useful as a resource to improve the best local cloning fidelity.

Sobriety Treatment and Recovery Teams: Implementation Fidelity and Related Outcomes.

PubMed

Huebner, Ruth A; Posze, Lynn; Willauer, Tina M; Hall, Martin T

2015-01-01

Although integrated programs between child welfare and substance abuse treatment are recommended for families with co-occurring child maltreatment and substance use disorders, implementing integrated service delivery strategies with fidelity is a challenging process. This study of the first five years of the Sobriety Treatment and Recovery Team (START) program examines implementation fidelity using a model proposed by Carroll et al. (2007). The study describes the process of strengthening moderators of implementation fidelity, trends in adherence to START service delivery standards, and trends in parent and child outcomes. Qualitative and quantitative measures were used to prospectively study three START sites serving 341 families with 550 parents and 717 children. To achieve implementation fidelity to service delivery standards required a pre-service year and two full years of operation, persistent leadership, and facilitative actions that challenged the existing paradigm. Over four years of service delivery, the time from the child protective services report to completion of five drug treatment sessions was reduced by an average of 75 days. This trend was associated with an increase in parent retention, parental sobriety, and parent retention of child custody. Conclusions/Importance: Understanding the implementation processes necessary to establish complex integrated programs may support realistic allocation of resources. Although implementation fidelity is a moderator of program outcome, complex inter-agency interventions may benefit from innovative measures of fidelity that promote improvement without extensive cost and data collection burden. The implementation framework applied in this study was useful in examining implementation processes, fidelity, and related outcomes.

Enforcing elemental mass and energy balances for reduced order models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, J.; Agarwal, K.; Sharma, P.

2012-01-01

Development of economically feasible gasification and carbon capture, utilization and storage (CCUS) technologies requires a variety of software tools to optimize the designs of not only the key devices involved (e., g., gasifier, CO{sub 2} adsorber) but also the entire power generation system. High-fidelity models such as Computational Fluid Dynamics (CFD) models are capable of accurately simulating the detailed flow dynamics, heat transfer, and chemistry inside the key devices. However, the integration of CFD models within steady-state process simulators, and subsequent optimization of the integrated system, still presents significant challenges due to the scale differences in both time and length,more » as well the high computational cost. A reduced order model (ROM) generated from a high-fidelity model can serve as a bridge between the models of different scales. While high-fidelity models are built upon the principles of mass, momentum, and energy conservations, ROMs are usually developed based on regression-type equations and hence their predictions may violate the mass and energy conservation laws. A high-fidelity model may also have the mass and energy balance problem if it is not tightly converged. Conservations of mass and energy are important when a ROM is integrated to a flowsheet for the process simulation of the entire chemical or power generation system, especially when recycle streams are connected to the modeled device. As a part of the Carbon Capture Simulation Initiative (CCSI) project supported by the U.S. Department of Energy, we developed a software framework for generating ROMs from CFD simulations and integrating them with Process Modeling Environments (PMEs) for system-wide optimization. This paper presents a method to correct the results of a high-fidelity model or a ROM such that the elemental mass and energy are conserved perfectly. Correction factors for the flow rates of individual species in the product streams are solved using a minimization algorithm based on Lagrangian multiplier method. Enthalpies of product streams are also modified to enforce the energy balance. The approach is illustrated for two ROMs, one based on a CFD model of an entrained-flow gasifier and the other based on the CFD model of a multiphase CO{sub 2} adsorber.« less

Experimental magic state distillation for fault-tolerant quantum computing.

PubMed

Souza, Alexandre M; Zhang, Jingfu; Ryan, Colm A; Laflamme, Raymond

2011-01-25

Any physical quantum device for quantum information processing (QIP) is subject to errors in implementation. In order to be reliable and efficient, quantum computers will need error-correcting or error-avoiding methods. Fault-tolerance achieved through quantum error correction will be an integral part of quantum computers. Of the many methods that have been discovered to implement it, a highly successful approach has been to use transversal gates and specific initial states. A critical element for its implementation is the availability of high-fidelity initial states, such as |0〉 and the 'magic state'. Here, we report an experiment, performed in a nuclear magnetic resonance (NMR) quantum processor, showing sufficient quantum control to improve the fidelity of imperfect initial magic states by distilling five of them into one with higher fidelity.

Synthetic Air Data Estimation: A case study of model-aided estimation

NASA Astrophysics Data System (ADS)

Lie, F. Adhika Pradipta

A method for estimating airspeed, angle of attack, and sideslip without using conventional, pitot-static airdata system is presented. The method relies on measurements from GPS, an inertial measurement unit (IMU) and a low-fidelity model of the aircraft's dynamics which are fused using two, cascaded Extended Kalman Filters. In the cascaded architecture, the first filter uses information from the IMU and GPS to estimate the aircraft's absolute velocity and attitude. These estimates are used as the measurement updates for the second filter where they are fused with the aircraft dynamics model to generate estimates of airspeed, angle of attack and sideslip. Methods for dealing with the time and inter-state correlation in the measurements coming from the first filter are discussed. Simulation and flight test results of the method are presented. Simulation results using high fidelity nonlinear model show that airspeed, angle of attack, and sideslip angle estimation errors are less than 0.5 m/s, 0.1 deg, and 0.2 deg RMS, respectively. Factors that affect the accuracy including the implication and impact of using a low fidelity aircraft model are discussed. It is shown using flight tests that a single linearized aircraft model can be used in lieu of a high-fidelity, non-linear model to provide reasonably accurate estimates of airspeed (less than 2 m/s error), angle of attack (less than 3 deg error), and sideslip angle (less than 5 deg error). This performance is shown to be relatively insensitive to off-trim attitudes but very sensitive to off-trim velocity.

Comprehensive modeling and control of flexible flapping wing micro air vehicles

NASA Astrophysics Data System (ADS)

Nogar, Stephen Michael

Flapping wing micro air vehicles hold significant promise due to the potential for improved aerodynamic efficiency, enhanced maneuverability and hover capability compared to fixed and rotary configurations. However, significant technical challenges exist to due the lightweight, highly integrated nature of the vehicle and coupling between the actuators, flexible wings and control system. Experimental and high fidelity analysis has demonstrated that aeroelastic effects can change the effective kinematics of the wing, reducing vehicle stability. However, many control studies for flapping wing vehicles do not consider these effects, and instead validate the control strategy with simple assumptions, including rigid wings, quasi-steady aerodynamics and no consideration of actuator dynamics. A control evaluation model that includes aeroelastic effects and actuator dynamics is developed. The structural model accounts for geometrically nonlinear behavior using an implicit condensation technique and the aerodynamic loads are found using a time accurate approach that includes quasi-steady, rotational, added mass and unsteady effects. Empirically based parameters in the model are fit using data obtained from a higher fidelity solver. The aeroelastic model and its ingredients are compared to experiments and computations using models of higher fidelity, and indicate reasonable agreement. The developed control evaluation model is implemented in a previously published, baseline controller that maintains stability using an asymmetric wingbeat, known as split-cycle, along with changing the flapping frequency and wing bias. The model-based controller determines the control inputs using a cycle-averaged, linear control design model, which assumes a rigid wing and no actuator dynamics. The introduction of unaccounted for dynamics significantly degrades the ability of the controller to track a reference trajectory, and in some cases destabilizes the vehicle. This demonstrates the importance of considering coupled aeroelastic and actuator dynamics in closed-loop control of flapping wings. A controller is developed that decouples the normal form of the vehicle dynamics, which accounts for coupling of the forces and moments acting on the vehicle and enables enhanced tuning capabilities. This controller, using the same control design model as the baseline controller, stabilizes the system despite the uncertainty between the control design and evaluation models. The controller is able to stabilize cases with significant wing flexibility and limited actuator capabilities, despite a reduction in control effectiveness. Additionally, to achieve a minimally actuated vehicle, the wing bias mechanism is removed. Using the same control design methodology, increased performance is observed compared to the baseline controller. However, due to the dependence on the split-cycle mechanism to generate a pitching moment instead of wing bias, the controller is more susceptible to instability from wing flexibility and limited actuator capacity. This work highlights the importance of coupled dynamics in the design and control of flapping wing micro air vehicles. Future enhancements to this work should focus on the reduced order structural and aerodynamics models. Applications include using the developed dynamics model to evaluate other kinematics and control schemes, ultimately enabling improved vehicle and control design.

[Acquiring skills in malignant hyperthermia crisis management: comparison of high-fidelity simulation versus computer-based case study].

PubMed

Mejía, Vilma; Gonzalez, Carlos; Delfino, Alejandro E; Altermatt, Fernando R; Corvetto, Marcia A

The primary purpose of this study was to compare the effect of high fidelity simulation versus a computer-based case solving self-study, in skills acquisition about malignant hyperthermia on first year anesthesiology residents. After institutional ethical committee approval, 31 first year anesthesiology residents were enrolled in this prospective randomized single-blinded study. Participants were randomized to either a High Fidelity Simulation Scenario or a computer-based Case Study about malignant hyperthermia. After the intervention, all subjects' performance in was assessed through a high fidelity simulation scenario using a previously validated assessment rubric. Additionally, knowledge tests and a satisfaction survey were applied. Finally, a semi-structured interview was done to assess self-perception of reasoning process and decision-making. 28 first year residents finished successfully the study. Resident's management skill scores were globally higher in High Fidelity Simulation versus Case Study, however they were significant in 4 of the 8 performance rubric elements: recognize signs and symptoms (p = 0.025), prioritization of initial actions of management (p = 0.003), recognize complications (p = 0.025) and communication (p = 0.025). Average scores from pre- and post-test knowledge questionnaires improved from 74% to 85% in the High Fidelity Simulation group, and decreased from 78% to 75% in the Case Study group (p = 0.032). Regarding the qualitative analysis, there was no difference in factors influencing the student's process of reasoning and decision-making with both teaching strategies. Simulation-based training with a malignant hyperthermia high-fidelity scenario was superior to computer-based case study, improving knowledge and skills in malignant hyperthermia crisis management, with a very good satisfaction level in anesthesia residents. Copyright © 2018 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Coupled Solid Rocket Motor Ballistics and Trajectory Modeling for Higher Fidelity Launch Vehicle Design

NASA Technical Reports Server (NTRS)

Ables, Brett

2014-01-01

Multi-stage launch vehicles with solid rocket motors (SRMs) face design optimization challenges, especially when the mission scope changes frequently. Significant performance benefits can be realized if the solid rocket motors are optimized to the changing requirements. While SRMs represent a fixed performance at launch, rapid design iterations enable flexibility at design time, yielding significant performance gains. The streamlining and integration of SRM design and analysis can be achieved with improved analysis tools. While powerful and versatile, the Solid Performance Program (SPP) is not conducive to rapid design iteration. Performing a design iteration with SPP and a trajectory solver is a labor intensive process. To enable a better workflow, SPP, the Program to Optimize Simulated Trajectories (POST), and the interfaces between them have been improved and automated, and a graphical user interface (GUI) has been developed. The GUI enables real-time visual feedback of grain and nozzle design inputs, enforces parameter dependencies, removes redundancies, and simplifies manipulation of SPP and POST's numerous options. Automating the analysis also simplifies batch analyses and trade studies. Finally, the GUI provides post-processing, visualization, and comparison of results. Wrapping legacy high-fidelity analysis codes with modern software provides the improved interface necessary to enable rapid coupled SRM ballistics and vehicle trajectory analysis. Low cost trade studies demonstrate the sensitivities of flight performance metrics to propulsion characteristics. Incorporating high fidelity analysis from SPP into vehicle design reduces performance margins and improves reliability. By flying an SRM designed with the same assumptions as the rest of the vehicle, accurate comparisons can be made between competing architectures. In summary, this flexible workflow is a critical component to designing a versatile launch vehicle model that can accommodate a volatile mission scope.

Comparison of fresh-frozen cadaver and high-fidelity virtual reality simulator as methods of laparoscopic training.

PubMed

Sharma, Mitesh; Horgan, Alan

2012-08-01

The aim of this study was to compare fresh-frozen cadavers (FFC) with a high-fidelity virtual reality simulator (VRS) as training tools in minimal access surgery for complex and relatively simple procedures. A prospective comparative face validity study between FFC and VRS (LAP Mentor(™)) was performed. Surgeons were recruited to perform tasks on both FFC and VRS appropriately paired to their experience level. Group A (senior) performed a laparoscopic sigmoid colectomy, Group B (intermediate) performed a laparoscopic incisional hernia repair, and Group C (junior) performed basic laparoscopic tasks (BLT) (camera manipulation, hand-eye coordination, tissue dissection and hand-transferring skills). Each subject completed a 5-point Likert-type questionnaire rating the training modalities in nine domains. Data were analysed using nonparametric tests. Forty-five surgeons were recruited to participate (15 per skill group). Median scores for subjects in Group A were significantly higher for evaluation of FFC in all nine domains compared to VRS (p < 0.01). Group B scored FFC significantly better (p < 0.05) in all domains except task replication (p = 0.06). Group C scored FFC significantly better (p < 0.01) in eight domains but not on performance feedback (p = 0.09). When compared across groups, juniors accepted VRS as a training model more than did intermediate and senior groups on most domains (p < 0.01) except team work. Fresh-frozen cadaver is perceived as a significantly overall better model for laparoscopic training than the high-fidelity VRS by all training grades, irrespective of the complexity of the operative procedure performed. VRS is still useful when training junior trainees in BLT.

Quantum phase transitions in a two-dimensional quantum XYX model: ground-state fidelity and entanglement.

PubMed

Li, Bo; Li, Sheng-Hao; Zhou, Huan-Qiang

2009-06-01

A systematic analysis is performed for quantum phase transitions in a two-dimensional anisotropic spin-1/2 antiferromagnetic XYX model in an external magnetic field. With the help of an innovative tensor network algorithm, we compute the fidelity per lattice site to demonstrate that the field-induced quantum phase transition is unambiguously characterized by a pinch point on the fidelity surface, marking a continuous phase transition. We also compute an entanglement estimator, defined as a ratio between the one-tangle and the sum of squared concurrences, to identify both the factorizing field and the critical point, resulting in a quantitative agreement with quantum Monte Carlo simulation. In addition, the local order parameter is "derived" from the tensor network representation of the system's ground-state wave functions.

Evaluating the Implementation Fidelity of Technology Immersion and Its Relationship with Student Achievement

ERIC Educational Resources Information Center

Shapley, Kelly S.; Sheehan, Daniel; Maloney, Catherine; Caranikas-Walker, Fanny

2010-01-01

In a pilot study of the Technology Immersion model, high-need middle schools were "immersed" in technology by providing a laptop for each student and teacher, wireless Internet access, curricular and assessment resources, professional development, and technical and pedagogical support. This article examines the fidelity of model…

Nursing Simulation: A Review of the Past 40 Years

ERIC Educational Resources Information Center

Nehring, Wendy M.; Lashley, Felissa R.

2009-01-01

Simulation, in its many forms, has been a part of nursing education and practice for many years. The use of games, computer-assisted instruction, standardized patients, virtual reality, and low-fidelity to high-fidelity mannequins have appeared in the past 40 years, whereas anatomical models, partial task trainers, and role playing were used…

Colonization and extinction in dynamic habitats: an occupancy approach for a Great Plains stream fish assemblage.

PubMed

Falke, Jeffrey A; Bailey, Larissa L; Fausch, Kurt D; Bestgen, Kevin R

2012-04-01

Despite the importance of habitat in determining species distribution and persistence, habitat dynamics are rarely modeled in studies of metapopulations. We used an integrated habitat-occupancy model to simultaneously quantify habitat change, site fidelity, and local colonization and extinction rates for larvae of a suite of Great Plains stream fishes in the Arikaree River, eastern Colorado, USA, across three years. Sites were located along a gradient of flow intermittency and groundwater connectivity. Hydrology varied across years: the first and third being relatively wet and the second dry. Despite hydrologic variation, our results indicated that site suitability was random from one year to the next. Occupancy probabilities were also independent of previous habitat and occupancy state for most species, indicating little site fidelity. Climate and groundwater connectivity were important drivers of local extinction and colonization, but the importance of groundwater differed between periods. Across species, site extinction probabilities were highest during the transition from wet to dry conditions (range: 0.52-0.98), and the effect of groundwater was apparent with higher extinction probabilities for sites not fed by groundwater. Colonization probabilities during this period were relatively low for both previously dry sites (range: 0.02-0.38) and previously wet sites (range: 0.02-0.43). In contrast, no sites dried or remained dry during the transition from dry to wet conditions, yielding lower but still substantial extinction probabilities (range: 0.16-0.63) and higher colonization probabilities (range: 0.06-0.86), with little difference among sites with and without groundwater. This approach of jointly modeling both habitat change and species occupancy will likely be useful to incorporate effects of dynamic habitat on metapopulation processes and to better inform appropriate conservation actions.

Features that contribute to the usefulness of low-fidelity models for surgical skills training.

PubMed

Langebæk, R; Berendt, M; Pedersen, L T; Jensen, A L; Eika, B

2012-04-07

For practical, ethical and economic reasons, veterinary surgical education is becoming increasingly dependent on models for training. The limited availability and high cost of commercially produced surgical models has increased the need for useful, low-cost alternatives. For this reason, a number of models were developed to be used in a basic surgical skills course for veterinary students. The models were low fidelity, having limited resemblance to real animals. The aim of the present study was to describe the students' learning experience with the models and to report their perception of the usefulness of the models in applying the trained skills to live animal surgery. One hundred and forty-six veterinary fourth-year students evaluated the models on a four-point Likert scale. Of these, 26 additionally participated in individual semistructured interviews. The survey results showed that 75 per cent of the students rated the models 'useful'/'very useful'. Interviews revealed that tactile, dimensional, visual, situational and emotional features are important to students' perception of a successful translation of skills from models to live animal. In conclusion, low-fidelity models are useful educational tools in preparation for live animal surgery. However, there are specific features to take into account when developing models in order for students to perceive them as useful.

Spawning site fidelity of wild and hatchery lake trout (Salvelinus namaycush) in northern Lake Huron

USGS Publications Warehouse

Binder, Thomas; Riley, Stephen C.; Holbrook, Christopher; Hansen, Michael J.; Bergstedt, Roger A.; Bronte, Charles R.; He, Ji; Krueger, Charles C.

2016-01-01

Fidelity to high-quality spawning sites helps ensure that adults repeatedly spawn at sites that maximize reproductive success. Fidelity is also an important behavioural characteristic to consider when hatchery-reared individuals are stocked for species restoration, because artificial rearing environments may interfere with cues that guide appropriate spawning site selection. Acoustic telemetry was used in conjunction with Cormack–Jolly–Seber capture–recapture models to compare degree of spawning site fidelity of wild and hatchery-reared lake trout (Salvelinus namaycush) in northern Lake Huron. Annual survival was estimated to be between 77% and 81% and did not differ among wild and hatchery males and females. Site fidelity estimates were high in both wild and hatchery-reared lake trout (ranging from 0.78 to 0.94, depending on group and time filter), but were slightly lower in hatchery-reared fish than in wild fish. The ecological implication of the small difference in site fidelity between wild and hatchery-reared lake trout is unclear, but similarities in estimates suggest that many hatchery-reared fish use similar spawning sites to wild fish and that most return to those sites annually for spawning.

Dynamic Response Testing in an Electrically Heated Reactor Test Facility

NASA Astrophysics Data System (ADS)

Bragg-Sitton, Shannon M.; Morton, T. J.

2006-01-01

Non-nuclear testing can be a valuable tool in the development of a space nuclear power or propulsion system. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Standard testing allows one to fully assess thermal, heat transfer, and stress related attributes of a given system, but fails to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. The integration of thermal hydraulic hardware tests with simulated neutronic response provides a bridge between electrically heated testing and fueled nuclear testing. By implementing a neutronic response model to simulate the dynamic response that would be expected in a fueled reactor system, one can better understand system integration issues, characterize integrated system response times and response characteristics, and assess potential design improvements at a relatively small fiscal investment. Initial system dynamic response testing was demonstrated on the integrated SAFE-100a heat pipe (HP) cooled, electrically heated reactor and heat exchanger hardware, utilizing a one-group solution to the point kinetics equations to simulate the expected neutronic response of the system. Reactivity feedback calculations were then based on a bulk reactivity feedback coefficient and measured average core temperature. This paper presents preliminary results from similar dynamic testing of a direct drive gas cooled reactor system (DDG), demonstrating the applicability of the testing methodology to any reactor type and demonstrating the variation in system response characteristics in different reactor concepts. Although the HP and DDG designs both utilize a fast spectrum reactor, the method of cooling the reactor differs significantly, leading to a variable system response that can be demonstrated and assessed in a non-nuclear test facility. Planned system upgrades to allow implementation of higher fidelity dynamic testing are also discussed. Proposed DDG testing will utilize a higher fidelity point kinetics model to control core power transients, and reactivity feedback will be based on localized feedback coefficients and several independent temperature measurements taken within the core block. This paper presents preliminary test results and discusses the methodology that will be implemented in follow-on DDG testing and the additional instrumentation required to implement high fidelity dynamic testing.

A stochastic wind turbine wake model based on new metrics for wake characterization: A stochastic wind turbine wake model based on new metrics for wake characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doubrawa, Paula; Barthelmie, Rebecca J.; Wang, Hui

Understanding the detailed dynamics of wind turbine wakes is critical to predicting the performance and maximizing the efficiency of wind farms. This knowledge requires atmospheric data at a high spatial and temporal resolution, which are not easily obtained from direct measurements. Therefore, research is often based on numerical models, which vary in fidelity and computational cost. The simplest models produce axisymmetric wakes and are only valid beyond the near wake. Higher-fidelity results can be obtained by solving the filtered Navier-Stokes equations at a resolution that is sufficient to resolve the relevant turbulence scales. This work addresses the gap between thesemore » two extremes by proposing a stochastic model that produces an unsteady asymmetric wake. The model is developed based on a large-eddy simulation (LES) of an offshore wind farm. Because there are several ways of characterizing wakes, the first part of this work explores different approaches to defining global wake characteristics. From these, a model is developed that captures essential features of a LES-generated wake at a small fraction of the cost. The synthetic wake successfully reproduces the mean characteristics of the original LES wake, including its area and stretching patterns, and statistics of the mean azimuthal radius. The mean and standard deviation of the wake width and height are also reproduced. This preliminary study focuses on reproducing the wake shape, while future work will incorporate velocity deficit and meandering, as well as different stability scenarios.« less

TESTING AN INTEGRATED MODEL OF PROGRAM IMPLEMENTATION: THE FOOD, HEALTH & CHOICES SCHOOL-BASED CHILDHOOD OBESITY PREVENTION INTERVENTION PROCESS EVALUATION

PubMed Central

Gray, Heewon Lee; Tipton, Elizabeth; Contento, Isobel; Koch, Pamela

2016-01-01

Childhood obesity is a complex, worldwide problem. Significant resources are invested in its prevention, and high-quality evaluations of these efforts are important. Conducting trials in school settings is complicated, making process evaluations useful for explaining results. Intervention fidelity has been demonstrated to influence outcomes, but others have suggested that other aspects of implementation, including participant responsiveness, should be examined more systematically. During Food, Health & Choices (FHC), a school-based childhood obesity prevention trial designed to test a curriculum and wellness policy taught by trained FHC instructors to fifth grade students in 20 schools during 2012–2013, we assessed relationships among facilitator behaviors (i.e., fidelity and teacher interest), participant behaviors (i.e., student satisfaction and recall), and program outcomes (i.e., energy balance-related behaviors) using hierarchical linear models, controlling for student, class, and school characteristics. We found positive relationships between student satisfaction and recall and program outcomes, but not fidelity and program outcomes. We also found relationships between teacher interest and fidelity when teachers participated in implementation. Finally, we found a significant interaction between fidelity and satisfaction on behavioral outcomes. These findings suggest that individual students in the same class responded differently to the same intervention. They also suggest the importance of teacher buy-in for successful intervention implementation. Future studies should examine how facilitator and participant behaviors together are related to both outcomes and implementation. Assessing multiple aspects of implementation using models that account for contextual influences on behavioral outcomes is an important step forward for prevention intervention process evaluations. PMID:27921200

Testing an Integrated Model of Program Implementation: the Food, Health & Choices School-Based Childhood Obesity Prevention Intervention Process Evaluation.

PubMed

Burgermaster, Marissa; Gray, Heewon Lee; Tipton, Elizabeth; Contento, Isobel; Koch, Pamela

2017-01-01

Childhood obesity is a complex, worldwide problem. Significant resources are invested in its prevention, and high-quality evaluations of these efforts are important. Conducting trials in school settings is complicated, making process evaluations useful for explaining results. Intervention fidelity has been demonstrated to influence outcomes, but others have suggested that other aspects of implementation, including participant responsiveness, should be examined more systematically. During Food, Health & Choices (FHC), a school-based childhood obesity prevention trial designed to test a curriculum and wellness policy taught by trained FHC instructors to fifth grade students in 20 schools during 2012-2013, we assessed relationships among facilitator behaviors (i.e., fidelity and teacher interest); participant behaviors (i.e., student satisfaction and recall); and program outcomes (i.e., energy balance-related behaviors) using hierarchical linear models, controlling for student, class, and school characteristics. We found positive relationships between student satisfaction and recall and program outcomes, but not fidelity and program outcomes. We also found relationships between teacher interest and fidelity when teachers participated in implementation. Finally, we found a significant interaction between fidelity and satisfaction on behavioral outcomes. These findings suggest that individual students in the same class responded differently to the same intervention. They also suggest the importance of teacher buy-in for successful intervention implementation. Future studies should examine how facilitator and participant behaviors together are related to both outcomes and implementation. Assessing multiple aspects of implementation using models that account for contextual influences on behavioral outcomes is an important step forward for prevention intervention process evaluations.

High-fidelity simulation of transcutaneous cardiac pacing: characteristics and limitations of available high-fidelity simulators, and description of an alternative two-mannequin model.

PubMed

Robitaille, Arnaud; Perron, Roger; Germain, Jean-François; Tanoubi, Issam; Georgescu, Mihai

2015-04-01

Transcutaneous cardiac pacing (TCP) is a potentially lifesaving technique that is part of the recommended treatment for symptomatic bradycardia. Transcutaneous cardiac pacing however is used uncommonly, and its successful application is not straightforward. Simulation could, therefore, play an important role in the teaching and assessment of TCP competence. However, even the highest-fidelity mannequins available on the market have important shortcomings, which limit the potential of simulation. Six criteria defining clinical competency in TCP were established and used as a starting point in the creation of an improved TCP simulator. The goal was a model that could be used to assess experienced clinicians, an objective that justifies the additional effort required by the increased fidelity. The proposed 2-mannequin model (TMM) combines a highly modified Human Patient Simulator with a SimMan 3G, the latter being used solely to provide the electrocardiography (ECG) tracing. The TMM improves the potential of simulation to assess experienced clinicians (1) by reproducing key features of TCP, like using the same multifunctional pacing electrodes used clinically, allowing dual ECG monitoring, and responding with upper body twitching when stimulated, but equally importantly (2) by reproducing key pitfalls of the technique, like allowing pacing electrode misplacement and reproducing false signs of ventricular capture, commonly, but erroneously, used clinically to establish that effective pacing has been achieved (like body twitching, electrical artifact on the ECG, and electrical capture without ventricular capture). The proposed TMM uses a novel combination of 2 high-fidelity mannequins to improve TCP simulation until upgraded mannequins become commercially available.

The effects of model composition design choices on high-fidelity simulations of motoneuron recruitment and firing behaviors

NASA Astrophysics Data System (ADS)

Allen, John M.; Elbasiouny, Sherif M.

2018-06-01

Objective. Computational models often require tradeoffs, such as balancing detail with efficiency; yet optimal balance should incorporate sound design features that do not bias the results of the specific scientific question under investigation. The present study examines how model design choices impact simulation results. Approach. We developed a rigorously-validated high-fidelity computational model of the spinal motoneuron pool to study three long-standing model design practices which have yet to be examined for their impact on motoneuron recruitment, firing rate, and force simulations. The practices examined were the use of: (1) generic cell models to simulate different motoneuron types, (2) discrete property ranges for different motoneuron types, and (3) biological homogeneity of cell properties within motoneuron types. Main results. Our results show that each of these practices accentuates conditions of motoneuron recruitment based on the size principle, and minimizes conditions of mixed and reversed recruitment orders, which have been observed in animal and human recordings. Specifically, strict motoneuron orderly size recruitment occurs, but in a compressed range, after which mixed and reverse motoneuron recruitment occurs due to the overlap in electrical properties of different motoneuron types. Additionally, these practices underestimate the motoneuron firing rates and force data simulated by existing models. Significance. Our results indicate that current modeling practices increase conditions of motoneuron recruitment based on the size principle, and decrease conditions of mixed and reversed recruitment order, which, in turn, impacts the predictions made by existing models on motoneuron recruitment, firing rate, and force. Additionally, mixed and reverse motoneuron recruitment generated higher muscle force than orderly size motoneuron recruitment in these simulations and represents one potential scheme to increase muscle efficiency. The examined model design practices, as well as the present results, are applicable to neuronal modeling throughout the nervous system.

The effects of model composition design choices on high-fidelity simulations of motoneuron recruitment and firing behaviors.

PubMed

Allen, John M; Elbasiouny, Sherif M

2018-06-01

Computational models often require tradeoffs, such as balancing detail with efficiency; yet optimal balance should incorporate sound design features that do not bias the results of the specific scientific question under investigation. The present study examines how model design choices impact simulation results. We developed a rigorously-validated high-fidelity computational model of the spinal motoneuron pool to study three long-standing model design practices which have yet to be examined for their impact on motoneuron recruitment, firing rate, and force simulations. The practices examined were the use of: (1) generic cell models to simulate different motoneuron types, (2) discrete property ranges for different motoneuron types, and (3) biological homogeneity of cell properties within motoneuron types. Our results show that each of these practices accentuates conditions of motoneuron recruitment based on the size principle, and minimizes conditions of mixed and reversed recruitment orders, which have been observed in animal and human recordings. Specifically, strict motoneuron orderly size recruitment occurs, but in a compressed range, after which mixed and reverse motoneuron recruitment occurs due to the overlap in electrical properties of different motoneuron types. Additionally, these practices underestimate the motoneuron firing rates and force data simulated by existing models. Our results indicate that current modeling practices increase conditions of motoneuron recruitment based on the size principle, and decrease conditions of mixed and reversed recruitment order, which, in turn, impacts the predictions made by existing models on motoneuron recruitment, firing rate, and force. Additionally, mixed and reverse motoneuron recruitment generated higher muscle force than orderly size motoneuron recruitment in these simulations and represents one potential scheme to increase muscle efficiency. The examined model design practices, as well as the present results, are applicable to neuronal modeling throughout the nervous system.

A cross-cultural comparison of children's imitative flexibility.

PubMed

Clegg, Jennifer M; Legare, Cristine H

2016-09-01

Recent research with Western populations has demonstrated that children use imitation flexibly to engage in both instrumental and conventional learning. Evidence for children's imitative flexibility in non-Western populations is limited, however, and has only assessed imitation of instrumental tasks. This study (N = 142, 6- to 8-year-olds) demonstrates both cultural continuity and cultural variation in imitative flexibility. Children engage in higher imitative fidelity for conventional tasks than for instrumental tasks in both an industrialized, Western culture (United States), and a subsistence-based, non-Western culture (Vanuatu). Children in Vanuatu engage in higher imitative fidelity of instrumental tasks than in the United States, a potential consequence of cultural variation in child socialization for conformity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

From concept to content: assessing the implementation fidelity of a chronic care model for frail, older people who live at home.

PubMed

Muntinga, Maaike E; Van Leeuwen, Karen M; Schellevis, François G; Nijpels, Giel; Jansen, Aaltje P D

2015-01-22

Implementation fidelity, the degree to which a care program is implemented as intended, can influence program impact. Since results of trials that aim to implement comprehensive care programs for frail, older people have been conflicting, assessing implementation fidelity alongside these trials is essential to differentiate between flaws inherent to the program and implementation issues. This study demonstrates how a theory-based assessment of fidelity can increase insight in the implementation process of a complex intervention in primary elderly care. The Geriatric Care Model was implemented among 35 primary care practices in the Netherlands. During home visits, practice nurses conducted a comprehensive geriatric assessment and wrote a tailored care plan. Multidisciplinary team consultations were organized with the aim to enhance the coordination between professionals caring for a single patient with complex needs. To assess fidelity, we identified 5 key intervention components and formulated corresponding research questions using Carroll's framework for fidelity. Adherence (coverage, frequency, duration, content) was assessed per intervention component during and at the end of the intervention period. Two moderating factors (participant responsiveness and facilitation strategies) were assessed at the end of the intervention. Adherence to the geriatric assessments and care plans was high, but decreased over time. Adherence to multidisciplinary consultations was initially poor, but increased over time. We found that individual differences in adherence between practice nurses and primary care physicians were moderate, while differences in participant responsiveness (satisfaction, involvement) were more distinct. Nurses deviated from protocol due to contextual factors and personal work routines. Adherence to the Geriatric Care Model was high for most of the essential intervention components. Study limitations include the limited number of assessed moderating factors. We argue that a longitudinal investigation of adherence per intervention component is essential for a complete understanding of the implementation process, but that such investigations may be complicated by practical and methodological challenges. The Netherlands National Trial Register (NTR). 2160 .

Effects of VR system fidelity on analyzing isosurface visualization of volume datasets.

PubMed

Laha, Bireswar; Bowman, Doug A; Socha, John J

2014-04-01

Volume visualization is an important technique for analyzing datasets from a variety of different scientific domains. Volume data analysis is inherently difficult because volumes are three-dimensional, dense, and unfamiliar, requiring scientists to precisely control the viewpoint and to make precise spatial judgments. Researchers have proposed that more immersive (higher fidelity) VR systems might improve task performance with volume datasets, and significant results tied to different components of display fidelity have been reported. However, more information is needed to generalize these results to different task types, domains, and rendering styles. We visualized isosurfaces extracted from synchrotron microscopic computed tomography (SR-μCT) scans of beetles, in a CAVE-like display. We ran a controlled experiment evaluating the effects of three components of system fidelity (field of regard, stereoscopy, and head tracking) on a variety of abstract task categories that are applicable to various scientific domains, and also compared our results with those from our prior experiment using 3D texture-based rendering. We report many significant findings. For example, for search and spatial judgment tasks with isosurface visualization, a stereoscopic display provides better performance, but for tasks with 3D texture-based rendering, displays with higher field of regard were more effective, independent of the levels of the other display components. We also found that systems with high field of regard and head tracking improve performance in spatial judgment tasks. Our results extend existing knowledge and produce new guidelines for designing VR systems to improve the effectiveness of volume data analysis.

Modelling the CDK-dependent transcription cycle in fission yeast.

PubMed

Sansó, Miriam; Fisher, Robert P

2013-12-01

CDKs (cyclin-dependent kinases) ensure directionality and fidelity of the eukaryotic cell division cycle. In a similar fashion, the transcription cycle is governed by a conserved subfamily of CDKs that phosphorylate Pol II (RNA polymerase II) and other substrates. A genetic model organism, the fission yeast Schizosaccharomyces pombe, has yielded robust models of cell-cycle control, applicable to higher eukaryotes. From a similar approach combining classical and chemical genetics, fundamental principles of transcriptional regulation by CDKs are now emerging. In the present paper, we review the current knowledge of each transcriptional CDK with respect to its substrate specificity, function in transcription and effects on chromatin modifications, highlighting the important roles of CDKs in ensuring quantity and quality control over gene expression in eukaryotes.

A quasi-3D wire approach to model pulmonary airflow in human airways.

PubMed

Kannan, Ravishekar; Chen, Z J; Singh, Narender; Przekwas, Andrzej; Delvadia, Renishkumar; Tian, Geng; Walenga, Ross

2017-07-01

The models used for modeling the airflow in the human airways are either 0-dimensional compartmental or full 3-dimensional (3D) computational fluid dynamics (CFD) models. In the former, airways are treated as compartments, and the computations are performed with several assumptions, thereby generating a low-fidelity solution. The CFD method displays extremely high fidelity since the solution is obtained by solving the conservation equations in a physiologically consistent geometry. However, CFD models (1) require millions of degrees of freedom to accurately describe the geometry and to reduce the discretization errors, (2) have convergence problems, and (3) require several days to simulate a few breathing cycles. In this paper, we present a novel, fast-running, and robust quasi-3D wire model for modeling the airflow in the human lung airway. The wire mesh is obtained by contracting the high-fidelity lung airway surface mesh to a system of connected wires, with well-defined radii. The conservation equations are then solved in each wire. These wire meshes have around O(1000) degrees of freedom and hence are 3000 to 25 000 times faster than their CFD counterparts. The 3D spatial nature is also preserved since these wires are contracted out of the actual lung STL surface. The pressure readings between the 2 approaches showed minor difference (maximum error = 15%). In general, this formulation is fast and robust, allows geometric changes, and delivers high-fidelity solutions. Hence, this approach has great potential for more complicated problems including modeling of constricted/diseased lung sections and for calibrating the lung flow resistances through parameter inversion. Copyright © 2016 John Wiley & Sons, Ltd.

Aerodynamic Optimization of Rocket Control Surface Geometry Using Cartesian Methods and CAD Geometry

NASA Technical Reports Server (NTRS)

Nelson, Andrea; Aftosmis, Michael J.; Nemec, Marian; Pulliam, Thomas H.

2004-01-01

Aerodynamic design is an iterative process involving geometry manipulation and complex computational analysis subject to physical constraints and aerodynamic objectives. A design cycle consists of first establishing the performance of a baseline design, which is usually created with low-fidelity engineering tools, and then progressively optimizing the design to maximize its performance. Optimization techniques have evolved from relying exclusively on designer intuition and insight in traditional trial and error methods, to sophisticated local and global search methods. Recent attempts at automating the search through a large design space with formal optimization methods include both database driven and direct evaluation schemes. Databases are being used in conjunction with surrogate and neural network models as a basis on which to run optimization algorithms. Optimization algorithms are also being driven by the direct evaluation of objectives and constraints using high-fidelity simulations. Surrogate methods use data points obtained from simulations, and possibly gradients evaluated at the data points, to create mathematical approximations of a database. Neural network models work in a similar fashion, using a number of high-fidelity database calculations as training iterations to create a database model. Optimal designs are obtained by coupling an optimization algorithm to the database model. Evaluation of the current best design then gives either a new local optima and/or increases the fidelity of the approximation model for the next iteration. Surrogate methods have also been developed that iterate on the selection of data points to decrease the uncertainty of the approximation model prior to searching for an optimal design. The database approximation models for each of these cases, however, become computationally expensive with increase in dimensionality. Thus the method of using optimization algorithms to search a database model becomes problematic as the number of design variables is increased.

Explaining outcomes in major system change: a qualitative study of implementing centralised acute stroke services in two large metropolitan regions in England.

PubMed

Fulop, Naomi J; Ramsay, Angus I G; Perry, Catherine; Boaden, Ruth J; McKevitt, Christopher; Rudd, Anthony G; Turner, Simon J; Tyrrell, Pippa J; Wolfe, Charles D A; Morris, Stephen

2016-06-03

Implementing major system change in healthcare is not well understood. This gap may be addressed by analysing change in terms of interrelated components identified in the implementation literature, including decision to change, intervention selection, implementation approaches, implementation outcomes, and intervention outcomes. We conducted a qualitative study of two cases of major system change: the centralisation of acute stroke services in Manchester and London, which were associated with significantly different implementation outcomes (fidelity to referral pathway) and intervention outcomes (provision of evidence-based care, patient mortality). We interviewed stakeholders at national, pan-regional, and service-levels (n = 125) and analysed 653 documents. Using a framework developed for this study from the implementation science literature, we examined factors influencing implementation approaches; how these approaches interacted with the models selected to influence implementation outcomes; and their relationship to intervention outcomes. London and Manchester's differing implementation outcomes were influenced by the different service models selected and implementation approaches used. Fidelity to the referral pathway was higher in London, where a 'simpler', more inclusive model was used, implemented with a 'big bang' launch and 'hands-on' facilitation by stroke clinical networks. In contrast, a phased approach of a more complex pathway was used in Manchester, and the network acted more as a platform to share learning. Service development occurred more uniformly in London, where service specifications were linked to financial incentives, and achieving standards was a condition of service launch, in contrast to Manchester. 'Hands-on' network facilitation, in the form of dedicated project management support, contributed to achievement of these standards in London; such facilitation processes were less evident in Manchester. Using acute stroke service centralisation in London and Manchester as an example, interaction between model selected and implementation approaches significantly influenced fidelity to the model. The contrasting implementation outcomes may have affected differences in provision of evidence-based care and patient mortality. The framework used in this analysis may support planning and evaluating major system changes, but would benefit from application in different healthcare contexts.

Microwave fidelity studies by varying antenna coupling

NASA Astrophysics Data System (ADS)

Köber, B.; Kuhl, U.; Stöckmann, H.-J.; Gorin, T.; Savin, D. V.; Seligman, T. H.

2010-09-01

The fidelity decay in a microwave billiard is considered, where the coupling to an attached antenna is varied. The resulting quantity, coupling fidelity, is experimentally studied for three different terminators of the varied antenna: a hard-wall reflection, an open wall reflection, and a 50Ω load, corresponding to a totally open channel. The model description in terms of an effective Hamiltonian with a complex coupling constant is given. Quantitative agreement is found with the theory obtained from a modified VWZ approach [J. J. M. Verbaarschot , Phys. Rep. 129, 367 (1985)10.1016/0370-1573(85)90070-5].

Modeling and Uncertainty Quantification of Vapor Sorption and Diffusion in Heterogeneous Polymers

DOE PAGES

Sun, Yunwei; Harley, Stephen J.; Glascoe, Elizabeth A.

2015-08-13

A high-fidelity model of kinetic and equilibrium sorption and diffusion is developed and exercised. The gas-diffusion model is coupled with a triple-sorption mechanism: Henry’s law absorption, Langmuir adsorption, and pooling or clustering of molecules at higher partial pressures. Sorption experiments are conducted and span a range of relative humidities (0-95%) and temperatures (30-60°C). Kinetic and equilibrium sorption properties and effective diffusivity are determined by minimizing the absolute difference between measured and modeled uptakes. Uncertainty quantification and sensitivity analysis methods are described and exercised herein to demonstrate the capability of this modeling approach. Water uptake in silica-filled and unfilled poly(dimethylsiloxane) networksmore » is investigated; however, the model is versatile enough to be used with a wide range of materials and vapors.« less

Simulation System Fidelity Assessment at the Vertical Motion Simulator

NASA Technical Reports Server (NTRS)

Beard, Steven D.; Reardon, Scott E.; Tobias, Eric L.; Aponso, Bimal L.

2013-01-01

Fidelity is a word that is often used but rarely understood when talking about groundbased simulation. Assessing the cueing fidelity of a ground based flight simulator requires a comparison to actual flight data either directly or indirectly. Two experiments were conducted at the Vertical Motion Simulator using the GenHel UH-60A Black Hawk helicopter math model that was directly compared to flight data. Prior to the experiment the simulator s motion and visual system frequency responses were measured, the aircraft math model was adjusted to account for the simulator motion system delays, and the motion system gains and washouts were tuned for the individual tasks. The tuned motion system fidelity was then assessed against the modified Sinacori criteria. The first experiments showed similar handling qualities ratings (HQRs) to actual flight for a bob-up and sidestep maneuvers. The second experiment showed equivalent HQRs between flight and simulation for the ADS33 slalom maneuver for the two pilot participants. The ADS33 vertical maneuver HQRs were mixed with one pilot rating the flight and simulation the same while the second pilot rated the simulation worse. In addition to recording HQRs on the second experiment, an experimental Simulation Fidelity Rating (SFR) scale developed by the University of Liverpool was tested for applicability to engineering simulators. A discussion of the SFR scale for use on the Vertical Motion Simulator is included in this paper.

Aerodynamic Simulation of Runback Ice Accretion

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Whalen, Edward A.; Busch, Greg T.; Bragg, Michael B.

2010-01-01

This report presents the results of recent investigations into the aerodynamics of simulated runback ice accretion on airfoils. Aerodynamic tests were performed on a full-scale model using a high-fidelity, ice-casting simulation at near-flight Reynolds (Re) number. The ice-casting simulation was attached to the leading edge of a 72-in. (1828.8-mm ) chord NACA 23012 airfoil model. Aerodynamic performance tests were conducted at the ONERA F1 pressurized wind tunnel over a Reynolds number range of 4.7?10(exp 6) to 16.0?10(exp 6) and a Mach (M) number ran ge of 0.10 to 0.28. For Re = 16.0?10(exp 6) and M = 0.20, the simulated runback ice accretion on the airfoil decreased the maximum lift coe fficient from 1.82 to 1.51 and decreased the stalling angle of attack from 18.1deg to 15.0deg. The pitching-moment slope was also increased and the drag coefficient was increased by more than a factor of two. In general, the performance effects were insensitive to Reynolds numb er and Mach number changes over the range tested. Follow-on, subscale aerodynamic tests were conducted on a quarter-scale NACA 23012 model (18-in. (457.2-mm) chord) at Re = 1.8?10(exp 6) and M = 0.18, using low-fidelity, geometrically scaled simulations of the full-scale castin g. It was found that simple, two-dimensional simulations of the upper- and lower-surface runback ridges provided the best representation of the full-scale, high Reynolds number iced-airfoil aerodynamics, whereas higher-fidelity simulations resulted in larger performance degrada tions. The experimental results were used to define a new subclassification of spanwise ridge ice that distinguishes between short and tall ridges. This subclassification is based upon the flow field and resulting aerodynamic characteristics, regardless of the physical size of the ridge and the ice-accretion mechanism.

Modeling Contamination Migration on the Chandra X-ray Observatory II

NASA Technical Reports Server (NTRS)

O'Dell, Steve; Swartz, Doug; Tice, Neil; Plucinsky, Paul; Grant, Catherine; Marshall, Herman; Vikhlinin, Alexey

2013-01-01

During its first 14 years of operation, the cold (about -60degC) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition may have changed, perhaps partially related to changes in the operating temperature of the ACIS housing. This evolution of the accumulation of the molecular contamination has motivated further analysis of contamination migration on the Chandra X-ray Observatory, particularly within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon monitored temperature data, and an accordingly refined model of the molecular transport.

END-DIASTOLIC FLOW REVERSAL LIMITS THE EFFICACY OF PEDIATRIC INTRAAORTIC BALLOON PUMP COUNTERPULSATION

PubMed Central

Bartoli, Carlo R.; Rogers, Benjamin D.; Ionan, Constantine E.; Koenig, Steven C.; Pantalos, George M.

2013-01-01

OBJECTIVE Counterpulsation with an intraaortic balloon pump (IABP) has not achieved the same successes or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. METHODS In Yorkshire piglets (n=19, 13.0±0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7cc) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. RESULTS Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105±3bmp, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. CONCLUSIONS Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. PMID:24139614

End-diastolic flow reversal limits the efficacy of pediatric intra-aortic balloon pump counterpulsation.

PubMed

Bartoli, Carlo R; Rogers, Benjamin D; Ionan, Constantine E; Pantalos, George M

2014-05-01

Counterpulsation with an intra-aortic balloon pump (IABP) has not achieved the same success or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. In Yorkshire piglets (n = 19; weight, 13.0 ± 0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7 mL) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105 ± 3 beats per minute, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Fidelity Failures in Brief Strategic Family Therapy for Adolescent Drug Abuse: A Clinical Analysis.

PubMed

Lebensohn-Chialvo, Florencia; Rohrbaugh, Michael J; Hasler, Brant P

2018-04-30

As evidence-based family treatments for adolescent substance use and conduct problems gain traction, cutting edge research moves beyond randomized efficacy trials to address questions such as how these treatments work and how best to disseminate them to community settings. A key factor in effective dissemination is treatment fidelity, which refers to implementing an intervention in a manner consistent with an established manual. While most fidelity research is quantitative, this study offers a qualitative clinical analysis of fidelity failures in a large, multisite effectiveness trial of Brief Strategic Family Therapy (BSFT) for adolescent drug abuse, where BSFT developers trained community therapists to administer this intervention in their own agencies. Using case notes and video recordings of therapy sessions, an independent expert panel first rated 103 cases on quantitative fidelity scales grounded in the BSFT manual and the broader structural-strategic framework that informs BSFT intervention. Because fidelity was generally low, the panel reviewed all cases qualitatively to identify emergent types or categories of fidelity failure. Ten categories of failures emerged, characterized by therapist omissions (e.g., failure to engage key family members, failure to think in threes) and commissions (e.g., off-model, nonsystemic formulations/interventions). Of these, "failure to think in threes" appeared basic and particularly problematic, reflecting the central place of this idea in structural theory and therapy. Although subject to possible bias, our observations highlight likely stumbling blocks in exporting a complex family treatment like BSFT to community settings. These findings also underscore the importance of treatment fidelity in family therapy research. © 2018 Family Process Institute.

Aeroacoustic Study of a High-Fidelity Aircraft Model. Part 2; Unsteady Surface Pressures

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R.; Neuhart, Danny H.

2012-01-01

In this paper, we present unsteady surface pressure measurements for an 18%-scale, semi-span Gulfstream aircraft model. This high-fidelity model is being used to perform detailed studies of airframe noise associated with main landing gear, flap components, and gear-flap interaction noise, as well as to evaluate novel noise reduction concepts. The aerodynamic segment of the tests, conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel, was completed in November 2010. To discern the characteristics of the surface pressure fluctuations in the vicinity of the prominent noise sources, unsteady sensors were installed on the inboard and outboard flap edges, and on the main gear wheels, struts, and door. Various configurations were tested, including flap deflections of 0?, 20?, and 39?, with and without the main landing gear. The majority of unsteady surface pressure measurements were acquired for the nominal landing configuration where the main gear was deployed and the flap was deflected 39?. To assess the Mach number variation of the surface pressure amplitudes, measurements were obtained at Mach numbers of 0.16, 0.20, and 0.24. Comparison of the unsteady surface pressures with the main gear on and off shows significant interaction between the gear wake and the inboard flap edge, resulting in higher amplitude fluctuations when the gear is present.

Low-fidelity bench models for basic surgical skills training during undergraduate medical education.

PubMed

Denadai, Rafael; Saad-Hossne, Rogério; Todelo, Andréia Padilha; Kirylko, Larissa; Souto, Luís Ricardo Martinhão

2014-01-01

It is remarkable the reduction in the number of medical students choosing general surgery as a career. In this context, new possibilities in the field of surgical education should be developed to combat this lack of interest. In this study, a program of surgical training based on learning with models of low-fidelity bench is designed as a complementary alternative to the various methodologies in the teaching of basic surgical skills during medical education, and to develop personal interests in career choice.

Multi-Fidelity Uncertainty Propagation for Cardiovascular Modeling

NASA Astrophysics Data System (ADS)

Fleeter, Casey; Geraci, Gianluca; Schiavazzi, Daniele; Kahn, Andrew; Marsden, Alison

2017-11-01

Hemodynamic models are successfully employed in the diagnosis and treatment of cardiovascular disease with increasing frequency. However, their widespread adoption is hindered by our inability to account for uncertainty stemming from multiple sources, including boundary conditions, vessel material properties, and model geometry. In this study, we propose a stochastic framework which leverages three cardiovascular model fidelities: 3D, 1D and 0D models. 3D models are generated from patient-specific medical imaging (CT and MRI) of aortic and coronary anatomies using the SimVascular open-source platform, with fluid structure interaction simulations and Windkessel boundary conditions. 1D models consist of a simplified geometry automatically extracted from the 3D model, while 0D models are obtained from equivalent circuit representations of blood flow in deformable vessels. Multi-level and multi-fidelity estimators from Sandia's open-source DAKOTA toolkit are leveraged to reduce the variance in our estimated output quantities of interest while maintaining a reasonable computational cost. The performance of these estimators in terms of computational cost reductions is investigated for a variety of output quantities of interest, including global and local hemodynamic indicators. Sandia National Labs is a multimission laboratory managed and operated by NTESS, LLC, for the U.S. DOE under contract DE-NA0003525. Funding for this project provided by NIH-NIBIB R01 EB018302.

High-Fidelity Modelng and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

DOE PAGES

Betzler, Benjamin R.; Chandler, David; Davidson, Eva E.; ...

2017-05-08

A high-fidelity model of the High Flux Isotope Reactor (HFIR) with a low-enriched uranium (LEU) fuel design and a representative experiment loading has been developed to serve as a new reference model for LEU conversion studies. With the exception of the fuel elements, this HFIR LEU model is completely consistent with the current highly enriched uranium HFIR model. Results obtained with the new LEU model provide a baseline for analysis of alternate LEU fuel designs and further optimization studies. The newly developed HFIR LEU model has an explicit representation of the HFIR-specific involute fuel plate geometry, including the within-plate fuelmore » meat contouring, and a detailed geometry model of the fuel element side plates. Such high-fidelity models are necessary to accurately account for the self-shielding from 238U and the depletion of absorber materials present in the side plates. In addition, a method was developed to account for fuel swelling in the high-density LEU fuel plates during the depletion simulation. In conclusion, calculated time-dependent metrics for the HFIR LEU model include fission rate and cumulative fission density distributions, flux and reaction rates for relevant experiment locations, point kinetics data, and reactivity coefficients.« less

High-Fidelity Modelng and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betzler, Benjamin R.; Chandler, David; Davidson, Eva E.

A high-fidelity model of the High Flux Isotope Reactor (HFIR) with a low-enriched uranium (LEU) fuel design and a representative experiment loading has been developed to serve as a new reference model for LEU conversion studies. With the exception of the fuel elements, this HFIR LEU model is completely consistent with the current highly enriched uranium HFIR model. Results obtained with the new LEU model provide a baseline for analysis of alternate LEU fuel designs and further optimization studies. The newly developed HFIR LEU model has an explicit representation of the HFIR-specific involute fuel plate geometry, including the within-plate fuelmore » meat contouring, and a detailed geometry model of the fuel element side plates. Such high-fidelity models are necessary to accurately account for the self-shielding from 238U and the depletion of absorber materials present in the side plates. In addition, a method was developed to account for fuel swelling in the high-density LEU fuel plates during the depletion simulation. In conclusion, calculated time-dependent metrics for the HFIR LEU model include fission rate and cumulative fission density distributions, flux and reaction rates for relevant experiment locations, point kinetics data, and reactivity coefficients.« less

Synergia: an accelerator modeling tool with 3-D space charge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amundson, James F.; Spentzouris, P.; /Fermilab

2004-07-01

High precision modeling of space-charge effects, together with accurate treatment of single-particle dynamics, is essential for designing future accelerators as well as optimizing the performance of existing machines. We describe Synergia, a high-fidelity parallel beam dynamics simulation package with fully three dimensional space-charge capabilities and a higher order optics implementation. We describe the computational techniques, the advanced human interface, and the parallel performance obtained using large numbers of macroparticles. We also perform code benchmarks comparing to semi-analytic results and other codes. Finally, we present initial results on particle tune spread, beam halo creation, and emittance growth in the Fermilab boostermore » accelerator.« less

Turbomachinery CFD on parallel computers

NASA Technical Reports Server (NTRS)

Blech, Richard A.; Milner, Edward J.; Quealy, Angela; Townsend, Scott E.

1992-01-01

The role of multistage turbomachinery simulation in the development of propulsion system models is discussed. Particularly, the need for simulations with higher fidelity and faster turnaround time is highlighted. It is shown how such fast simulations can be used in engineering-oriented environments. The use of parallel processing to achieve the required turnaround times is discussed. Current work by several researchers in this area is summarized. Parallel turbomachinery CFD research at the NASA Lewis Research Center is then highlighted. These efforts are focused on implementing the average-passage turbomachinery model on MIMD, distributed memory parallel computers. Performance results are given for inviscid, single blade row and viscous, multistage applications on several parallel computers, including networked workstations.

An Investigation of State-Space Model Fidelity for SSME Data

NASA Technical Reports Server (NTRS)

Martin, Rodney Alexander

2008-01-01

In previous studies, a variety of unsupervised anomaly detection techniques for anomaly detection were applied to SSME (Space Shuttle Main Engine) data. The observed results indicated that the identification of certain anomalies were specific to the algorithmic method under consideration. This is the reason why one of the follow-on goals of these previous investigations was to build an architecture to support the best capabilities of all algorithms. We appeal to that goal here by investigating a cascade, serial architecture for the best performing and most suitable candidates from previous studies. As a precursor to a formal ROC (Receiver Operating Characteristic) curve analysis for validation of resulting anomaly detection algorithms, our primary focus here is to investigate the model fidelity as measured by variants of the AIC (Akaike Information Criterion) for state-space based models. We show that placing constraints on a state-space model during or after the training of the model introduces a modest level of suboptimality. Furthermore, we compare the fidelity of all candidate models including those embodying the cascade, serial architecture. We make recommendations on the most suitable candidates for application to subsequent anomaly detection studies as measured by AIC-based criteria.

A Reduced-Order Model For Zero-Mass Synthetic Jet Actuators

NASA Technical Reports Server (NTRS)

Yamaleev, Nail K.; Carpenter, Mark H.; Vatsa, Veer S.

2007-01-01

Accurate details of the general performance of fluid actuators is desirable over a range of flow conditions, within some predetermined error tolerance. Designers typically model actuators with different levels of fidelity depending on the acceptable level of error in each circumstance. Crude properties of the actuator (e.g., peak mass rate and frequency) may be sufficient for some designs, while detailed information is needed for other applications (e.g., multiple actuator interactions). This work attempts to address two primary objectives. The first objective is to develop a systematic methodology for approximating realistic 3-D fluid actuators, using quasi-1-D reduced-order models. Near full fidelity can be achieved with this approach at a fraction of the cost of full simulation and only a modest increase in cost relative to most actuator models used today. The second objective, which is a direct consequence of the first, is to determine the approximate magnitude of errors committed by actuator model approximations of various fidelities. This objective attempts to identify which model (ranging from simple orifice exit boundary conditions to full numerical simulations of the actuator) is appropriate for a given error tolerance.

Automatic 3D high-fidelity traffic interchange modeling using 2D road GIS data

NASA Astrophysics Data System (ADS)

Wang, Jie; Shen, Yuzhong

2011-03-01

3D road models are widely used in many computer applications such as racing games and driving simulations. However, almost all high-fidelity 3D road models were generated manually by professional artists at the expense of intensive labor. There are very few existing methods for automatically generating 3D high-fidelity road networks, especially for those existing in the real world. Real road network contains various elements such as road segments, road intersections and traffic interchanges. Among them, traffic interchanges present the most challenges to model due to their complexity and the lack of height information (vertical position) of traffic interchanges in existing road GIS data. This paper proposes a novel approach that can automatically produce 3D high-fidelity road network models, including traffic interchange models, from real 2D road GIS data that mainly contain road centerline information. The proposed method consists of several steps. The raw road GIS data are first preprocessed to extract road network topology, merge redundant links, and classify road types. Then overlapped points in the interchanges are detected and their elevations are determined based on a set of level estimation rules. Parametric representations of the road centerlines are then generated through link segmentation and fitting, and they have the advantages of arbitrary levels of detail with reduced memory usage. Finally a set of civil engineering rules for road design (e.g., cross slope, superelevation) are selected and used to generate realistic road surfaces. In addition to traffic interchange modeling, the proposed method also applies to other more general road elements. Preliminary results show that the proposed method is highly effective and useful in many applications.

Towards multiscale modeling of influenza infection

PubMed Central

Murillo, Lisa N.; Murillo, Michael S.; Perelson, Alan S.

2013-01-01

Aided by recent advances in computational power, algorithms, and higher fidelity data, increasingly detailed theoretical models of infection with influenza A virus are being developed. We review single scale models as they describe influenza infection from intracellular to global scales, and, in particular, we consider those models that capture details specific to influenza and can be used to link different scales. We discuss the few multiscale models of influenza infection that have been developed in this emerging field. In addition to discussing modeling approaches, we also survey biological data on influenza infection and transmission that is relevant for constructing influenza infection models. We envision that, in the future, multiscale models that capitalize on technical advances in experimental biology and high performance computing could be used to describe the large spatial scale epidemiology of influenza infection, evolution of the virus, and transmission between hosts more accurately. PMID:23608630

A Theoretical Solid Oxide Fuel Cell Model for Systems Controls and Stability Design

NASA Technical Reports Server (NTRS)

Kopasakis, George; Brinson, Thomas; Credle, Sydni

2008-01-01

As the aviation industry moves toward higher efficiency electrical power generation, all electric aircraft, or zero emissions and more quiet aircraft, fuel cells are sought as the technology that can deliver on these high expectations. The hybrid solid oxide fuel cell system combines the fuel cell with a micro-turbine to obtain up to 70% cycle efficiency, and then distributes the electrical power to the loads via a power distribution system. The challenge is to understand the dynamics of this complex multidiscipline system and the design distributed controls that take the system through its operating conditions in a stable and safe manner while maintaining the system performance. This particular system is a power generation and a distribution system, and the fuel cell and micro-turbine model fidelity should be compatible with the dynamics of the power distribution system in order to allow proper stability and distributed controls design. The novelty in this paper is that, first, the case is made why a high fidelity fuel cell mode is needed for systems control and stability designs. Second, a novel modeling approach is proposed for the fuel cell that will allow the fuel cell and the power system to be integrated and designed for stability, distributed controls, and other interface specifications. This investigation shows that for the fuel cell, the voltage characteristic should be modeled but in addition, conservation equation dynamics, ion diffusion, charge transfer kinetics, and the electron flow inherent impedance should also be included.

High-Fidelity Modeling for Health Monitoring in Honeycomb Sandwich Structures

NASA Technical Reports Server (NTRS)

Luchinsky, Dimitry G.; Hafiychuk, Vasyl; Smelyanskiy, Vadim; Tyson, Richard W.; Walker, James L.; Miller, Jimmy L.

2011-01-01

High-Fidelity Model of the sandwich composite structure with real geometry is reported. The model includes two composite facesheets, honeycomb core, piezoelectric actuator/sensors, adhesive layers, and the impactor. The novel feature of the model is that it includes modeling of the impact and wave propagation in the structure before and after the impact. Results of modeling of the wave propagation, impact, and damage detection in sandwich honeycomb plates using piezoelectric actuator/sensor scheme are reported. The results of the simulations are compared with the experimental results. It is shown that the model is suitable for analysis of the physics of failure due to the impact and for testing structural health monitoring schemes based on guided wave propagation.

Can we teach core clinical obstetrics and gynaecology skills using low fidelity simulation in an interprofessional setting?

PubMed

Kumar, Arunaz; Gilmour, Carole; Nestel, Debra; Aldridge, Robyn; McLelland, Gayle; Wallace, Euan

2014-12-01

Core clinical skills acquisition is an essential component of undergraduate medical and midwifery education. Although interprofessional education is an increasingly common format for learning efficient teamwork in clinical medicine, its value in undergraduate education is less clear. We present a collaborative effort from the medical and midwifery schools of Monash University, Melbourne, towards the development of an educational package centred around a core skills-based workshop using low fidelity simulation models in an interprofessional setting. Detailed feedback on the package was positive with respect to the relevance of the teaching content, whether the topic was well taught by task trainers and simulation models used, pitch of level of teaching and perception of confidence gained in performing the skill on a real patient after attending the workshop. Overall, interprofessional core skills training using low fidelity simulation models introduced at an undergraduate level in medicine and midwifery had a good acceptance. © 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

Developing Capture Mechanisms and High-Fidelity Dynamic Models for the MXER Tether System

NASA Technical Reports Server (NTRS)

Canfield, Steven L.

2007-01-01

A team consisting of collaborators from Tennessee Technological University (TTU), Marshall Space Flight Center, BD Systems, and the University of Delaware (herein called the TTU team) conducted specific research and development activities in MXER tether systems during the base period of May 15, 2004 through September 30, 2006 under contract number NNM04AB13C. The team addressed two primary topics related to the MXER tether system: 1) Development of validated high-fidelity dynamic models of an elastic rotating tether and 2) development of feasible mechanisms to enable reliable rendezvous and capture. This contractor report will describe in detail the activities that were performed during the base period of this cycle-2 MXER tether activity and will summarize the results of this funded activity. The primary deliverables of this project were the quad trap, a robust capture mechanism proposed, developed, tested, and demonstrated with a high degree of feasibility and the detailed development of a validated high-fidelity elastic tether dynamic model provided through multiple formulations.

Simulations of High Speed Fragment Trajectories

NASA Astrophysics Data System (ADS)

Yeh, Peter; Attaway, Stephen; Arunajatesan, Srinivasan; Fisher, Travis

2017-11-01

Flying shrapnel from an explosion are capable of traveling at supersonic speeds and distances much farther than expected due to aerodynamic interactions. Predicting the trajectories and stable tumbling modes of arbitrary shaped fragments is a fundamental problem applicable to range safety calculations, damage assessment, and military technology. Traditional approaches rely on characterizing fragment flight using a single drag coefficient, which may be inaccurate for fragments with large aspect ratios. In our work we develop a procedure to simulate trajectories of arbitrary shaped fragments with higher fidelity using high performance computing. We employ a two-step approach in which the force and moment coefficients are first computed as a function of orientation using compressible computational fluid dynamics. The force and moment data are then input into a six-degree-of-freedom rigid body dynamics solver to integrate trajectories in time. Results of these high fidelity simulations allow us to further understand the flight dynamics and tumbling modes of a single fragment. Furthermore, we use these results to determine the validity and uncertainty of inexpensive methods such as the single drag coefficient model.

Models and methods for assessing the value of HVDC and MVDC technologies in modern power grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makarov, Yuri V.; Elizondo, Marcelo A.; O'Brien, James G.

This report reflects the results of U.S. Department of Energy’s (DOE) Grid Modernization project 0074 “Models and methods for assessing the value of HVDC [high-voltage direct current] and MTDC [multi-terminal direct current] technologies in modern power grids.” The work was done by the Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) in cooperation with Mid-Continent Independent System Operator (MISO) and Siemens. The main motivation of this study was to show the benefit of using direct current (DC) systems larger than those in existence today as they overlap with the alternating current (AC) systems. Proper use of theirmore » flexibility in terms of active/reactive power control and fast response can provide much-needed services to the grid at the same time as moving large blocks of energy to take advantage of cost diversity. Ultimately, the project’s success will enable decision-makers and investors to make well-informed decisions regarding this use of DC systems. This project showed the technical feasibility of HVDC macrogrid for frequency control and congestion relief in addition to bulk power transfers. Industry-established models for commonly used technologies were employed, along with high-fidelity models for recently developed HVDC converter technologies; like the modular multilevel converters (MMCs), a voltage source converters (VSC). Models for General Electric Positive Sequence Load Flow (GE PSLF) and Siemens Power System Simulator (PSS/E), widely used analysis programs, were for the first time adapted to include at the same time both Western Electricity Coordinating Council (WECC) and Eastern Interconnection (EI), the two largest North American interconnections. The high-fidelity models and their control were developed in detail for MMC system and extended to HVDC systems in point-to-point and in three-node multi-terminal configurations. Using a continental-level mixed AC-DC grid model, and using a HVDC macrogrid power flow and transient stability model, the results showed that the HVDC macrogrid relieved congestion and mitigated loop flows in AC networks, and provided up to 24% improvement in frequency responses. These are realistic studies, based on the 2025 heavy summer and EI multi-regional modeling working group (MMWG) 2026 summer peak cases. This work developed high-fidelity models and simulation algorithms to understand the dynamics of MMC. The developed models and simulation algorithms are up to 25 times faster than the existing algorithms. Models and control algorithms for high-fidelity models were designed and tested for point-to-point and multi-terminal configurations. The multi-terminal configuration was tested connecting simplified models of EI, WI, and Electric Reliability Council of Texas (ERCOT). The developed models showed up to 45% improvement in frequency response with the connection of all the three asynchronous interconnections in the United States using fast and advanced DC technologies like the multi-terminal MMC-DC system. Future work will look into developing high-fidelity models of other advanced DC technologies, combining high-fidelity models with the continental-level model, incorporating additional services. More scenarios involving large-scale HVDC and MTDC will be evaluated.« less

Overview of High-Fidelity Modeling Activities in the Numerical Propulsion System Simulations (NPSS) Project

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

2002-01-01

A high-fidelity simulation of a commercial turbofan engine has been created as part of the Numerical Propulsion System Simulation Project. The high-fidelity computer simulation utilizes computer models that were developed at NASA Glenn Research Center in cooperation with turbofan engine manufacturers. The average-passage (APNASA) Navier-Stokes based viscous flow computer code is used to simulate the 3D flow in the compressors and turbines of the advanced commercial turbofan engine. The 3D National Combustion Code (NCC) is used to simulate the flow and chemistry in the advanced aircraft combustor. The APNASA turbomachinery code and the NCC combustor code exchange boundary conditions at the interface planes at the combustor inlet and exit. This computer simulation technique can evaluate engine performance at steady operating conditions. The 3D flow models provide detailed knowledge of the airflow within the fan and compressor, the high and low pressure turbines, and the flow and chemistry within the combustor. The models simulate the performance of the engine at operating conditions that include sea level takeoff and the altitude cruise condition.

Comparison of the PHISICS/RELAP5-3D ring and block model results for phase I of the OECD/NEA MHTGR-350 benchmark

DOE PAGES

Strydom, G.; Epiney, A. S.; Alfonsi, Andrea; ...

2015-12-02

The PHISICS code system has been under development at INL since 2010. It consists of several modules providing improved coupled core simulation capability: INSTANT (3D nodal transport core calculations), MRTAU (depletion and decay heat generation) and modules performing criticality searches, fuel shuffling and generalized perturbation. Coupling of the PHISICS code suite to the thermal hydraulics system code RELAP5-3D was finalized in 2013, and as part of the verification and validation effort the first phase of the OECD/NEA MHTGR-350 Benchmark has now been completed. The theoretical basis and latest development status of the coupled PHISICS/RELAP5-3D tool are described in more detailmore » in a concurrent paper. This paper provides an overview of the OECD/NEA MHTGR-350 Benchmark and presents the results of Exercises 2 and 3 defined for Phase I. Exercise 2 required the modelling of a stand-alone thermal fluids solution at End of Equilibrium Cycle for the Modular High Temperature Reactor (MHTGR). The RELAP5-3D results of four sub-cases are discussed, consisting of various combinations of coolant bypass flows and material thermophysical properties. Exercise 3 required a coupled neutronics and thermal fluids solution, and the PHISICS/RELAP5-3D code suite was used to calculate the results of two sub-cases. The main focus of the paper is a comparison of results obtained with the traditional RELAP5-3D “ring” model approach against a much more detailed model that include kinetics feedback on individual block level and thermal feedbacks on a triangular sub-mesh. The higher fidelity that can be obtained by this “block” model is illustrated with comparison results on the temperature, power density and flux distributions. Furthermore, it is shown that the ring model leads to significantly lower fuel temperatures (up to 10%) when compared with the higher fidelity block model, and that the additional model development and run-time efforts are worth the gains obtained in the improved spatial temperature and flux distributions.« less

Neural correlates of individual differences in manual imitation fidelity

PubMed Central

Braadbaart, Lieke; Waiter, Gordon D.; Williams, Justin H. G.

2012-01-01

Imitation is crucial for social learning, and so it is important to identify what determines between-subject variability in imitation fidelity. This might help explain what makes some people, like those with social difficulties such as in autism spectrum disorder (ASD), significantly worse at performance on these tasks than others. A novel paradigm was developed to provide objective measures of imitation fidelity in which participants used a touchscreen to imitate videos of a model drawing different shapes. Comparisons between model and participants' kinematic data provided three measures of imitative fidelity. We hypothesized that imitative ability would predict variation in BOLD signal whilst performing a simple imitation task in the MRI-scanner. In particular, an overall measure of accuracy (correlation between model and imitator) would predict activity in the overarching imitation system, whereas bias would be subject to more general aspects of motor control. Participants lying in the MRI-scanner were instructed to imitate different grips on a handle, or to watch someone or a circle moving the handle. Our hypothesis was partly confirmed as correlation between model and imitator was mediated by somatosensory cortex but also ventromedial prefrontal cortex, and bias was mediated mainly by cerebellum but also by the medial frontal and parietal cortices and insula. We suggest that this variance differentially reflects cognitive functions such as feedback-sensitivity and reward-dependent learning, contributing significantly to variability in individuals' imitative abilities as characterized by objective kinematic measures. PMID:23087625

Low-fidelity Venezuelan equine encephalitis virus polymerase mutants to improve live-attenuated vaccine safety and efficacy

PubMed Central

Kautz, Tiffany F; Guerbois, Mathilde; Khanipov, Kamil; Yun, Ruimei; Warmbrod, Kelsey L; Fofanov, Yuriy; Weaver, Scott C; Forrester, Naomi L

2018-01-01

Abstract During RNA virus replication, there is the potential to incorporate mutations that affect virulence or pathogenesis. For live-attenuated vaccines, this has implications for stability, as replication may result in mutations that either restore the wild-type phenotype via reversion or compensate for the attenuating mutations by increasing virulence (pseudoreversion). Recent studies have demonstrated that altering the mutation rate of an RNA virus is an effective attenuation tool. To validate the safety of low-fidelity mutations to increase vaccine attenuation, several mutations in the RNA-dependent RNA-polymerase (RdRp) were tested in the live-attenuated Venezuelan equine encephalitis virus vaccine strain, TC-83. Next generation sequencing after passage in the presence of mutagens revealed a mutant containing three mutations in the RdRp, TC-83 3x, to have decreased replication fidelity, while a second mutant, TC-83 4x displayed no change in fidelity, but shared many phenotypic characteristics with TC-83 3x. Both mutants exhibited increased, albeit inconsistent attenuation in an infant mouse model, as well as increased immunogenicity and complete protection against lethal challenge of an adult murine model compared with the parent TC-83. During serial passaging in a highly permissive model, the mutants increased in virulence but remained less virulent than the parent TC-83. These results suggest that the incorporation of low-fidelity mutations into the RdRp of live-attenuated vaccines for RNA viruses can confer increased immunogenicity whilst showing some evidence of increased attenuation. However, while in theory such constructs may result in more effective vaccines, the instability of the vaccine phenotype decreases the likelihood of this being an effective vaccine strategy. PMID:29593882

The effects of using high-fidelity simulators and standardized patients on the thorax, lung, and cardiac examination skills of undergraduate nursing students.

PubMed

Tuzer, Hilal; Dinc, Leyla; Elcin, Melih

2016-10-01

Existing research literature indicates that the use of various simulation techniques in the training of physical examination skills develops students' cognitive and psychomotor abilities in a realistic learning environment while improving patient safety. The study aimed to compare the effects of the use of a high-fidelity simulator and standardized patients on the knowledge and skills of students conducting thorax-lungs and cardiac examinations, and to explore the students' views and learning experiences. A mixed-method explanatory sequential design. The study was conducted in the Simulation Laboratory of a Nursing School, the Training Center at the Faculty of Medicine, and in the inpatient clinics of the Education and Research Hospital. Fifty-two fourth-year nursing students. Students were randomly assigned to Group I and Group II. The students in Group 1 attended the thorax-lungs and cardiac examination training using a high-fidelity simulator, while the students in Group 2 using standardized patients. After the training sessions, all students practiced their skills on real patients in the clinical setting under the supervision of the investigator. Knowledge and performance scores of all students increased following the simulation activities; however, the students that worked with standardized patients achieved significantly higher knowledge scores than those that worked with the high-fidelity simulator; however, there was no significant difference in performance scores between the groups. The mean performance scores of students on real patients were significantly higher compared to the post-simulation assessment scores (p<0.001). Results of this study revealed that use of standardized patients was more effective than the use of a high-fidelity simulator in increasing the knowledge scores of students on thorax-lungs and cardiac examinations; however, practice on real patients increased performance scores of all students without any significant difference in two groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fidelity considerations in translational research: Eating As Treatment - a stepped wedge, randomised controlled trial of a dietitian delivered behaviour change counselling intervention for head and neck cancer patients undergoing radiotherapy.

PubMed

Beck, Alison Kate; Baker, Amanda; Britton, Ben; Wratten, Chris; Bauer, Judith; Wolfenden, Luke; Carter, Gregory

2015-10-15

The confidence with which researchers can comment on intervention efficacy relies on evaluation and consideration of intervention fidelity. Accordingly, there have been calls to increase the transparency with which fidelity methodology is reported. Despite this, consideration and/or reporting of fidelity methods remains poor. We seek to address this gap by describing the methodology for promoting and facilitating the evaluation of intervention fidelity in The EAT (Eating As Treatment) project: a multi-site stepped wedge randomised controlled trial of a dietitian delivered behaviour change counselling intervention to improve nutrition (primary outcome) in head and neck cancer patients undergoing radiotherapy. In accordance with recommendations from the National Institutes of Health Behaviour Change Consortium Treatment Fidelity Workgroup, we sought to maximise fidelity in this stepped wedge randomised controlled trial via strategies implemented from study design through to provider training, intervention delivery and receipt. As the EAT intervention is designed to be incorporated into standard dietetic consultations, we also address unique challenges for translational research. We offer a strong model for improving the quality of translational findings via real world application of National Institutes of Health Behaviour Change Consortium recommendations. Greater transparency in the reporting of behaviour change research is an important step in improving the progress and quality of behaviour change research. ACTRN12613000320752 (Date of registration 21 March 2013).

A Hybrid Process Fidelity Assessment in a Home-based Randomized Clinical Trial

PubMed Central

WILDE, MARY H.; LIEBEL, DIANNE; FAIRBANKS, EILEEN; WILSON, PAULA; LASH, MARGARET; SHAH, SHIVANI; McDONALD, MARGARET V.; BRASCH, JUDITH; ZHANG, FENG; SCHEID, EILEEN; McMAHON, JAMES M.

2016-01-01

A process fidelity assessment was conducted as a nested study within a home-based randomized clinical trial teaching self-management to 101 long-term indwelling urinary catheter users in the treatment group. Our hybrid model combined external assessments (outside observations and tape recordings) with internal evaluation methods (through study nurse forms and notes) for a comprehensive process fidelity assessment. Barriers, patient-related issues, and nurse perspectives were identified demonstrating the complexity in home care intervention research. The complementary and synergistic approaches provided in depth information about the context of the delivery and the impact of the intervention on study outcomes. PMID:25894688

High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits.

PubMed

Ballance, C J; Harty, T P; Linke, N M; Sepiol, M A; Lucas, D M

2016-08-05

We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed-fidelity trade-off for the two-qubit gate, for gate times between 3.8  μs and 520  μs, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.

A Case Study with Green Dot Public Schools on Managing the Tension between Fidelity and Adaptation When Scaling-Up

ERIC Educational Resources Information Center

Cevallos, Pedro F., Jr.

2009-01-01

This dissertation was a single case study with Green Dot Public Schools (GDPS) describing their rapid scale-up process. Specifically, it investigates the phenomenon of the inherent tension between maintaining the fidelity of the original model school's design, culture and values with local adaptation of the brand by stakeholders at the expansion…

A Case Study with Green Dot Public Schools on Managing the Tension between Fidelity and Adaptation when Scaling-Up

ERIC Educational Resources Information Center

Cevallos, Pedro Felipe, Jr.

2009-01-01

This dissertation was a single case study with Green Dot Public Schools (GDPS) describing their rapid scale-up process. Specifically, it investigates the phenomenon of the inherent tension between maintaining the fidelity of the original model school's design, culture and values with local adaptation of the brand by stakeholders at the expansion…

Exploring the Impact of Engaged Teachers on Implementation Fidelity and Reading Skill Gains in a Blended Learning Reading Program

ERIC Educational Resources Information Center

Schechter, Rachel L.; Kazakoff, Elizabeth R.; Bundschuh, Kristine; Prescott, Jen Elise; Macaruso, Paul

2017-01-01

The number of K-12 classrooms adopting blended learning models is rapidly increasing and represents a cultural shift in teaching and learning; however, fidelity of implementation of these new blended learning programs varies widely. This study aimed to examine the role of teacher engagement in student motivation and achievement in a blended…

High-Fidelity Multidisciplinary Design Optimization of Aircraft Configurations

NASA Technical Reports Server (NTRS)

Martins, Joaquim R. R. A.; Kenway, Gaetan K. W.; Burdette, David; Jonsson, Eirikur; Kennedy, Graeme J.

2017-01-01

To evaluate new airframe technologies we need design tools based on high-fidelity models that consider multidisciplinary interactions early in the design process. The overarching goal of this NRA is to develop tools that enable high-fidelity multidisciplinary design optimization of aircraft configurations, and to apply these tools to the design of high aspect ratio flexible wings. We develop a geometry engine that is capable of quickly generating conventional and unconventional aircraft configurations including the internal structure. This geometry engine features adjoint derivative computation for efficient gradient-based optimization. We also added overset capability to a computational fluid dynamics solver, complete with an adjoint implementation and semiautomatic mesh generation. We also developed an approach to constraining buffet and started the development of an approach for constraining utter. On the applications side, we developed a new common high-fidelity model for aeroelastic studies of high aspect ratio wings. We performed optimal design trade-o s between fuel burn and aircraft weight for metal, conventional composite, and carbon nanotube composite wings. We also assessed a continuous morphing trailing edge technology applied to high aspect ratio wings. This research resulted in the publication of 26 manuscripts so far, and the developed methodologies were used in two other NRAs. 1

Demonstration of a High-Fidelity Predictive/Preview Display Technique for Telerobotic Servicing in Space

NASA Technical Reports Server (NTRS)

Kim, Won S.; Bejczy, Antal K.

1993-01-01

A highly effective predictive/preview display technique for telerobotic servicing in space under several seconds communication time delay has been demonstrated on a large laboratory scale in May 1993, involving the Jet Propulsion Laboratory as the simulated ground control station and, 2500 miles away, the Goddard Space Flight Center as the simulated satellite servicing set-up. The technique is based on a high-fidelity calibration procedure that enables a high-fidelity overlay of 3-D graphics robot arm and object models over given 2-D TV camera images of robot arm and objects. To generate robot arm motions, the operator can confidently interact in real time with the graphics models of the robot arm and objects overlaid on an actual camera view of the remote work site. The technique also enables the operator to generate high-fidelity synthetic TV camera views showing motion events that are hidden in a given TV camera view or for which no TV camera views are available. The positioning accuracy achieved by this technique for a zoomed-in camera setting was about +/-5 mm, well within the allowable +/-12 mm error margin at the insertion of a 45 cm long tool in the servicing task.

Operational fidelity to an evidence-based HIV prevention intervention for people living with HIV/AIDS.

PubMed

Kalichman, Seth C; Hudd, Katie; Diberto, Giorgio

2010-08-01

Evidence-based interventions are often disseminated in public health education with little known about their operational fidelity. This study examined the delivery of intervention components (operational fidelity) of a widely disseminated HIV prevention program designed for people living with HIV/AIDS named Healthy Relationships. Two hundred ninety-nine agencies that had been trained in the intervention by the Centers for Disease Control and Prevention were contacted, and 122 (41%) completed confidential interviews. Among the 93 agencies that implemented the program, 39 (40%) adapted at least one core element activity, and 21 (23%) dropped an activity. Most adaptations were intended to improve the community fit of the intervention. Agencies believed that funders demand that they implement the intervention with fidelity. Models of technology transfer that emphasize behavior change processes rather than specific curriculum content may advance prevention program dissemination.

Dynamical phase transitions at finite temperature from fidelity and interferometric Loschmidt echo induced metrics

NASA Astrophysics Data System (ADS)

Mera, Bruno; Vlachou, Chrysoula; Paunković, Nikola; Vieira, Vítor R.; Viyuela, Oscar

2018-03-01

We study finite-temperature dynamical quantum phase transitions (DQPTs) by means of the fidelity and the interferometric Loschmidt echo (LE) induced metrics. We analyze the associated dynamical susceptibilities (Riemannian metrics), and derive analytic expressions for the case of two-band Hamiltonians. At zero temperature, the two quantities are identical, nevertheless, at finite temperatures they behave very differently. Using the fidelity LE, the zero-temperature DQPTs are gradually washed away with temperature, while the interferometric counterpart exhibits finite-temperature phase transitions. We analyze the physical differences between the two finite-temperature LE generalizations, and argue that, while the interferometric one is more sensitive and can therefore provide more information when applied to genuine quantum (microscopic) systems, when analyzing many-body macroscopic systems, the fidelity-based counterpart is a more suitable quantity to study. Finally, we apply the previous results to two representative models of topological insulators in one and two dimensions.

Implementation fidelity of Multidimensional Family Therapy in an international trial.

PubMed

Rowe, Cynthia; Rigter, Henk; Henderson, Craig; Gantner, Andreas; Mos, Kees; Nielsen, Philip; Phan, Olivier

2013-04-01

Implementation fidelity, a critical aspect of clinical trials research that establishes adequate delivery of the treatment as prescribed in treatment manuals and protocols, is also essential to the successful implementation of effective programs into new practice settings. Although infrequently studied in the drug abuse field, stronger implementation fidelity has been linked to better outcomes in practice but appears to be more difficult to achieve with greater distance from model developers. In the INternational CAnnabis Need for Treatment (INCANT) multi-national randomized clinical trial, investigators tested the effectiveness of Multidimensional Family Therapy (MDFT) in comparison to individual psychotherapy (IP) in Brussels, Berlin, Paris, The Hague, and Geneva with 450 adolescents with a cannabis use disorder and their parents. This study reports on the implementation fidelity of MDFT across these five Western European sites in terms of treatment adherence, dose and program differentiation, and discusses possible implications for international implementation efforts. Copyright © 2013 Elsevier Inc. All rights reserved.

Simulation Assisted Risk Assessment: Blast Overpressure Modeling

NASA Technical Reports Server (NTRS)

Lawrence, Scott L.; Gee, Ken; Mathias, Donovan; Olsen, Michael

2006-01-01

A probabilistic risk assessment (PRA) approach has been developed and applied to the risk analysis of capsule abort during ascent. The PRA is used to assist in the identification of modeling and simulation applications that can significantly impact the understanding of crew risk during this potentially dangerous maneuver. The PRA approach is also being used to identify the appropriate level of fidelity for the modeling of those critical failure modes. The Apollo launch escape system (LES) was chosen as a test problem for application of this approach. Failure modes that have been modeled and/or simulated to date include explosive overpressure-based failure, explosive fragment-based failure, land landing failures (range limits exceeded either near launch or Mode III trajectories ending on the African continent), capsule-booster re-contact during separation, and failure due to plume-induced instability. These failure modes have been investigated using analysis tools in a variety of technical disciplines at various levels of fidelity. The current paper focuses on the development and application of a blast overpressure model for the prediction of structural failure due to overpressure, including the application of high-fidelity analysis to predict near-field and headwinds effects.

Toward fidelity between specification and implementation

NASA Technical Reports Server (NTRS)

Callahan, John R.; Montgomery, Todd L.; Morrison, Jeff; Wu, Yunqing

1994-01-01

This paper describes the methods used to specify and implement a complex communications protocol that provides reliable delivery of data in multicast-capable, packet-switching telecommunication networks. The protocol, called the Reliable Multicasting Protocol (RMP), was developed incrementally by two complementary teams using a combination of formal and informal techniques in an attempt to ensure the correctness of the protocol implementation. The first team, called the Design team, initially specified protocol requirements using a variant of SCR requirements tables and implemented a prototype solution. The second team, called the V&V team, developed a state model based on the requirements tables and derived test cases from these tables to exercise the implementation. In a series of iterative steps, the Design team added new functionality to the implementation while the V&V team kept the state model in fidelity with the implementation through testing. Test cases derived from state transition paths in the formal model formed the dialogue between teams during development and served as the vehicles for keeping the model and implementation in fidelity with each other. This paper describes our experiences in developing our process model, details of our approach, and some example problems found during the development of RMP.

Point-of-care ultrasound education: the increasing role of simulation and multimedia resources.

PubMed

Lewiss, Resa E; Hoffmann, Beatrice; Beaulieu, Yanick; Phelan, Mary Beth

2014-01-01

This article reviews the current technology, literature, teaching models, and methods associated with simulation-based point-of-care ultrasound training. Patient simulation appears particularly well suited for learning point-of-care ultrasound, which is a required core competency for emergency medicine and other specialties. Work hour limitations have reduced the opportunities for clinical practice, and simulation enables practicing a skill multiple times before it may be used on patients. Ultrasound simulators can be categorized into 2 groups: low and high fidelity. Low-fidelity simulators are usually static simulators, meaning that they have nonchanging anatomic examples for sonographic practice. Advantages are that the model may be reused over time, and some simulators can be homemade. High-fidelity simulators are usually high-tech and frequently consist of many computer-generated cases of virtual sonographic anatomy that can be scanned with a mock probe. This type of equipment is produced commercially and is more expensive. High-fidelity simulators provide students with an active and safe learning environment and make a reproducible standardized assessment of many different ultrasound cases possible. The advantages and disadvantages of using low- versus high-fidelity simulators are reviewed. An additional concept used in simulation-based ultrasound training is blended learning. Blended learning may include face-to-face or online learning often in combination with a learning management system. Increasingly, with simulation and Web-based learning technologies, tools are now available to medical educators for the standardization of both ultrasound skills training and competency assessment.

High Fidelity, “Faster than Real-Time” Simulator for Predicting Power System Dynamic Behavior - Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flueck, Alex

The “High Fidelity, Faster than Real­Time Simulator for Predicting Power System Dynamic Behavior” was designed and developed by Illinois Institute of Technology with critical contributions from Electrocon International, Argonne National Laboratory, Alstom Grid and McCoy Energy. Also essential to the project were our two utility partners: Commonwealth Edison and AltaLink. The project was a success due to several major breakthroughs in the area of large­scale power system dynamics simulation, including (1) a validated faster than real­ time simulation of both stable and unstable transient dynamics in a large­scale positive sequence transmission grid model, (2) a three­phase unbalanced simulation platform formore » modeling new grid devices, such as independently controlled single­phase static var compensators (SVCs), (3) the world’s first high fidelity three­phase unbalanced dynamics and protection simulator based on Electrocon’s CAPE program, and (4) a first­of­its­ kind implementation of a single­phase induction motor model with stall capability. The simulator results will aid power grid operators in their true time of need, when there is a significant risk of cascading outages. The simulator will accelerate performance and enhance accuracy of dynamics simulations, enabling operators to maintain reliability and steer clear of blackouts. In the long­term, the simulator will form the backbone of the newly conceived hybrid real­time protection and control architecture that will coordinate local controls, wide­area measurements, wide­area controls and advanced real­time prediction capabilities. The nation’s citizens will benefit in several ways, including (1) less down time from power outages due to the faster­than­real­time simulator’s predictive capability, (2) higher levels of reliability due to the detailed dynamics plus protection simulation capability, and (3) more resiliency due to the three­ phase unbalanced simulator’s ability to model three­phase and single­ phase networks and devices.« less

Multi-Fidelity Simulation of a Turbofan Engine With Results Zoomed Into Mini-Maps for a Zero-D Cycle Simulation

NASA Technical Reports Server (NTRS)

Turner, Mark G.; Reed, John A.; Ryder, Robert; Veres, Joseph P.

2004-01-01

A Zero-D cycle simulation of the GE90-94B high bypass turbofan engine has been achieved utilizing mini-maps generated from a high-fidelity simulation. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled 3D computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the 3D component models are integrated into the cycle model via partial performance maps generated from the CFD flow solutions using one-dimensional mean line turbomachinery programs. This paper highlights the generation of the high-pressure compressor, booster, and fan partial performance maps, as well as turbine maps for the high pressure and low pressure turbine. These are actually "mini-maps" in the sense that they are developed only for a narrow operating range of the component. Results are compared between actual cycle data at a take-off condition and the comparable condition utilizing these mini-maps. The mini-maps are also presented with comparison to actual component data where possible.

Territoriality, site fidelity, and survivorship of willow flycatchers wintering in Costa Rica

USGS Publications Warehouse

Koronkiewicz, T.J.; Sogge, M.K.; van Riper, Charles; Paxton, E.H.

2006-01-01

We studied wintering Willow Flycatchers (Empidonax traillii) in two seasonal freshwater wetland habitats in northwestern Costa Rica during five boreal winters, to determine habitat occupancy, overwinter and between-year site and territory fidelity, and the degree to which the sexes maintain and defend winter territories. Both males and females used agonistic displays, song, and other vocalizations to maintain and defend mutually exclusive winter territories. Males were generally more abundant than females, but this varied by site and year. There was no significant difference in male and female territory size, nor any indication of sexual habitat segregation. Similarity in morphology and aggressiveness between the sexes may account for the lack of habitat segregation and the ability of females to maintain territories at wintering sites. Each year, 80%-92% of banded flycatchers that were present in midwinter remained at the site until late winter; of these, 86%-100% of individuals maintained the same territories throughout the entire period. We also observed nonterritorial floaters that subsequently established and held winter territories. Between-year site fidelity averaged 68%, and almost all returning birds established territories with boundaries similar to the previous year. Between-year apparent survivorship estimates ranged annually from 54%-72%, with no difference between sites but weak support for higher survivorship of males compared to females. Values for winter site and territory fidelity were generally higher than those reported for other species and for Willow Flycatchers on the breeding grounds; between-year survivorship estimates were similar to those reported for breeding flycatchers. ?? The Cooper Ornithological Society 2006.

Integration of Engine, Plume, and CFD Analyses in Conceptual Design of Low-Boom Supersonic Aircraft

NASA Technical Reports Server (NTRS)

Li, Wu; Campbell, Richard; Geiselhart, Karl; Shields, Elwood; Nayani, Sudheer; Shenoy, Rajiv

2009-01-01

This paper documents an integration of engine, plume, and computational fluid dynamics (CFD) analyses in the conceptual design of low-boom supersonic aircraft, using a variable fidelity approach. In particular, the Numerical Propulsion Simulation System (NPSS) is used for propulsion system cycle analysis and nacelle outer mold line definition, and a low-fidelity plume model is developed for plume shape prediction based on NPSS engine data and nacelle geometry. This model provides a capability for the conceptual design of low-boom supersonic aircraft that accounts for plume effects. Then a newly developed process for automated CFD analysis is presented for CFD-based plume and boom analyses of the conceptual geometry. Five test cases are used to demonstrate the integrated engine, plume, and CFD analysis process based on a variable fidelity approach, as well as the feasibility of the automated CFD plume and boom analysis capability.

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry: Spray Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutland, Christopher J.

2009-04-26

The Terascale High-Fidelity Simulations of Turbulent Combustion (TSTC) project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of the approach is direct numerical simulation (DNS) featuring the highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. Under this component of the TSTC program the simulation code named S3D, developed and shared with coworkers at Sandia National Laboratories, has been enhanced with newmore » numerical algorithms and physical models to provide predictive capabilities for turbulent liquid fuel spray dynamics. Major accomplishments include improved fundamental understanding of mixing and auto-ignition in multi-phase turbulent reactant mixtures and turbulent fuel injection spray jets.« less

Analysis procedures and subjective flight results of a simulator validation and cue fidelity experiment

NASA Technical Reports Server (NTRS)

Carr, Peter C.; Mckissick, Burnell T.

1988-01-01

A joint experiment to investigate simulator validation and cue fidelity was conducted by the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden) and NASA Langley Research Center. The primary objective was to validate the use of a closed-loop pilot-vehicle mathematical model as an analytical tool for optimizing the tradeoff between simulator fidelity requirements and simulator cost. The validation process includes comparing model predictions with simulation and flight test results to evaluate various hypotheses for differences in motion and visual cues and information transfer. A group of five pilots flew air-to-air tracking maneuvers in the Langley differential maneuvering simulator and visual motion simulator and in an F-14 aircraft at Ames-Dryden. The simulators used motion and visual cueing devices including a g-seat, a helmet loader, wide field-of-view horizon, and a motion base platform.

Plasma Model V&V of Collisionless Electrostatic Shock

NASA Astrophysics Data System (ADS)

Martin, Robert; Le, Hai; Bilyeu, David; Gildea, Stephen

2014-10-01

A simple 1D electrostatic collisionless shock was selected as an initial validation and verification test case for a new plasma modeling framework under development at the Air Force Research Laboratory's In-Space Propulsion branch (AFRL/RQRS). Cross verification between PIC, Vlasov, and Fluid plasma models within the framework along with expected theoretical results will be shown. The non-equilibrium velocity distributions (VDF) captured by PIC and Vlasov will be compared to each other and the assumed VDF of the fluid model at selected points. Validation against experimental data from the University of California, Los Angeles double-plasma device will also be presented along with current work in progress at AFRL/RQRS towards reproducing the experimental results using higher fidelity diagnostics to help elucidate differences between model results and between the models and original experiment. DISTRIBUTION A: Approved for public release; unlimited distribution; PA (Public Affairs) Clearance Number 14332.

Design of Quasi-Terminator Orbits near Primitive Bodies

NASA Technical Reports Server (NTRS)

Lantoine, Gregory; Broschart, Stephen B.; Grebow, Daniel J.

2013-01-01

Quasi-terminator orbits are a class of quasi-periodic orbits around a primitive body that exist in the vicinity of the well-known terminator orbits. The inherent stability of quasi-terminator trajectories and their wide variety of viewing geometries make them a very compelling option for primitive body mapping missions. In this paper, we discuss orbit design methodologies for selection of an appropriate quasi-terminator orbit that would meet the needs of a specific mission. Convergence of these orbits in an eccentric, higher-fidelity model is also discussed with an example case at Bennu, the target of the upcoming NASA's OSIRIS-REx mission.

General misincorporation frequency: Re-evaluation of the fidelity of DNA polymerases.

PubMed

Yang, Jie; Li, Bianbian; Liu, Xiaoying; Tang, Hong; Zhuang, Xiyao; Yang, Mingqi; Xu, Ying; Zhang, Huidong; Yang, Chun

2018-02-19

DNA replication in cells is performed in the presence of four dNTPs and four rNTPs. In this study, we re-evaluated the fidelity of DNA polymerases using the general misincorporation frequency consisting of three incorrect dNTPs and four rNTPs but not using the traditional special misincorporation frequency with only the three incorrect dNTPs. We analyzed both the general and special misincorporation frequencies of nucleotide incorporation opposite dG, rG, or 8-oxoG by Pseudomonas aeruginosa phage 1 (PaP1) DNA polymerase Gp90 or Sulfolobus solfataricus DNA polymerase Dpo4. Both misincorporation frequencies of other DNA polymerases published were also summarized and analyzed. The general misincorporation frequency is obviously higher than the special misincorporation frequency for many DNA polymerases, indicating the real fidelity of a DNA polymerase should be evaluated using the general misincorporation frequency. Copyright © 2018 Elsevier Inc. All rights reserved.

Teleportation of a two-mode entangled coherent state encoded with two-qubit information

NASA Astrophysics Data System (ADS)

Mishra, Manoj K.; Prakash, Hari

2010-09-01

We propose a scheme to teleport a two-mode entangled coherent state encoded with two-qubit information, which is better than the two schemes recently proposed by Liao and Kuang (2007 J. Phys. B: At. Mol. Opt. Phys. 40 1183) and by Phien and Nguyen (2008 Phys. Lett. A 372 2825) in that our scheme gives higher value of minimum assured fidelity and minimum average fidelity without using any nonlinear interactions. For involved coherent states | ± αrang, minimum average fidelity in our case is >=0.99 for |α| >= 1.6 (i.e. |α|2 >= 2.6), while previously proposed schemes referred above report the same for |α| >= 5 (i.e. |α|2 >= 25). Since it is very challenging to produce superposed coherent states of high coherent amplitude (|α|), our teleportation scheme is at the reach of modern technology.

Advancing methods for reliably assessing motivational interviewing fidelity using the Motivational Interviewing Skills Code

PubMed Central

Lord, Sarah Peregrine; Can, Doğan; Yi, Michael; Marin, Rebeca; Dunn, Christopher W.; Imel, Zac E.; Georgiou, Panayiotis; Narayanan, Shrikanth; Steyvers, Mark; Atkins, David C.

2014-01-01

The current paper presents novel methods for collecting MISC data and accurately assessing reliability of behavior codes at the level of the utterance. The MISC 2.1 was used to rate MI interviews from five randomized trials targeting alcohol and drug use. Sessions were coded at the utterance-level. Utterance-based coding reliability was estimated using three methods and compared to traditional reliability estimates of session tallies. Session-level reliability was generally higher compared to reliability using utterance-based codes, suggesting that typical methods for MISC reliability may be biased. These novel methods in MI fidelity data collection and reliability assessment provided rich data for therapist feedback and further analyses. Beyond implications for fidelity coding, utterance-level coding schemes may elucidate important elements in the counselor-client interaction that could inform theories of change and the practice of MI. PMID:25242192

Advancing methods for reliably assessing motivational interviewing fidelity using the motivational interviewing skills code.

PubMed

Lord, Sarah Peregrine; Can, Doğan; Yi, Michael; Marin, Rebeca; Dunn, Christopher W; Imel, Zac E; Georgiou, Panayiotis; Narayanan, Shrikanth; Steyvers, Mark; Atkins, David C

2015-02-01

The current paper presents novel methods for collecting MISC data and accurately assessing reliability of behavior codes at the level of the utterance. The MISC 2.1 was used to rate MI interviews from five randomized trials targeting alcohol and drug use. Sessions were coded at the utterance-level. Utterance-based coding reliability was estimated using three methods and compared to traditional reliability estimates of session tallies. Session-level reliability was generally higher compared to reliability using utterance-based codes, suggesting that typical methods for MISC reliability may be biased. These novel methods in MI fidelity data collection and reliability assessment provided rich data for therapist feedback and further analyses. Beyond implications for fidelity coding, utterance-level coding schemes may elucidate important elements in the counselor-client interaction that could inform theories of change and the practice of MI. Copyright © 2015 Elsevier Inc. All rights reserved.

Study on validation method for femur finite element model under multiple loading conditions

NASA Astrophysics Data System (ADS)

Guan, Fengjiao; Zhang, Guanjun; Liu, Jie; Wang, Shujing; Luo, Xu

2018-03-01

Acquisition of accurate and reliable constitutive parameters related to bio-tissue materials was beneficial to improve biological fidelity of a Finite Element (FE) model and predict impact damages more effectively. In this paper, a femur FE model was established under multiple loading conditions with diverse impact positions. Then, based on sequential response surface method and genetic algorithms, the material parameters identification was transformed to a multi-response optimization problem. Finally, the simulation results successfully coincided with force-displacement curves obtained by numerous experiments. Thus, computational accuracy and efficiency of the entire inverse calculation process were enhanced. This method was able to effectively reduce the computation time in the inverse process of material parameters. Meanwhile, the material parameters obtained by the proposed method achieved higher accuracy.

Cortical Representations of Speech in a Multitalker Auditory Scene.

PubMed

Puvvada, Krishna C; Simon, Jonathan Z

2017-09-20

The ability to parse a complex auditory scene into perceptual objects is facilitated by a hierarchical auditory system. Successive stages in the hierarchy transform an auditory scene of multiple overlapping sources, from peripheral tonotopically based representations in the auditory nerve, into perceptually distinct auditory-object-based representations in the auditory cortex. Here, using magnetoencephalography recordings from men and women, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in distinct hierarchical stages of the auditory cortex. Using systems-theoretic methods of stimulus reconstruction, we show that the primary-like areas in the auditory cortex contain dominantly spectrotemporal-based representations of the entire auditory scene. Here, both attended and ignored speech streams are represented with almost equal fidelity, and a global representation of the full auditory scene with all its streams is a better candidate neural representation than that of individual streams being represented separately. We also show that higher-order auditory cortical areas, by contrast, represent the attended stream separately and with significantly higher fidelity than unattended streams. Furthermore, the unattended background streams are more faithfully represented as a single unsegregated background object rather than as separated objects. Together, these findings demonstrate the progression of the representations and processing of a complex acoustic scene up through the hierarchy of the human auditory cortex. SIGNIFICANCE STATEMENT Using magnetoencephalography recordings from human listeners in a simulated cocktail party environment, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in separate hierarchical stages of the auditory cortex. We show that the primary-like areas in the auditory cortex use a dominantly spectrotemporal-based representation of the entire auditory scene, with both attended and unattended speech streams represented with almost equal fidelity. We also show that higher-order auditory cortical areas, by contrast, represent an attended speech stream separately from, and with significantly higher fidelity than, unattended speech streams. Furthermore, the unattended background streams are represented as a single undivided background object rather than as distinct background objects. Copyright © 2017 the authors 0270-6474/17/379189-08$15.00/0.

Assessing the link between implementation fidelity and health outcomes for a trial of intensive case management by community health workers: a mixed methods study protocol.

PubMed

Schmidt, Barbara; Watt, Kerrianne; McDermott, Robyn; Mills, Jane

2017-07-17

Better systems of care are required to address chronic disease in Indigenous people to ensure they can access all their care needs. Health research has produced evidence about effective models of care and chronic disease strategies to address Indigenous health, however the transfer of research findings into routine clinical practice has proven challenging. Complex interventions, such as those related to chronic disease, have many components that are often poorly implemented and hence rarely achieve implementation fidelity. Implementation fidelity is "the degree to which programs are implemented as intended by the program developer". Knowing if an intervention was implemented as planned is fundamental to knowing what has contributed to the success of an intervention. The aim of this study is to adapt the implementation fidelity framework developed by Keith et al. and apply it to the intervention implemented in phase 1 of the Getting Better at Chronic Care in North Queensland study. The objectives are to quantify the level of implementation fidelity achieved during phase 1 of the study, measure the association between implementation fidelity and health outcomes and to explore the features of the primary health care system that contributed to improved health outcomes. A convergent parallel mixed methods study design will be used to develop a process for assessing implementation fidelity. Information collected via a questionnaire and routine data generated during phase 1 of the study will be used to explain the context for the intervention in each site and develop an implementation fidelity score for each component of the intervention. A weighting will be applied to each component of the intervention to calculate the overall implementation score for each participating community. Statistical analysis will assess the level of association between implementation fidelity scores and health outcomes. Health services research seeks to find solutions to social and technical problems to improve health outcomes. The development of a tool and methodology for assessing implementation fidelity in the Indigenous primary health care context will help address some of the barriers to the translation of research into practice. ACTRN12610000812099 : 29.9.2010.

Effects of Low- Versus High-Fidelity Simulations on the Cognitive Burden and Performance of Entry-Level Paramedicine Students: A Mixed-Methods Comparison Trial Using Eye-Tracking, Continuous Heart Rate, Difficulty Rating Scales, Video Observation and Interviews.

PubMed

Mills, Brennen W; Carter, Owen B-J; Rudd, Cobie J; Claxton, Louise A; Ross, Nathan P; Strobel, Natalie A

2016-02-01

High-fidelity simulation-based training is often avoided for early-stage students because of the assumption that while practicing newly learned skills, they are ill suited to processing multiple demands, which can lead to "cognitive overload" and poorer learning outcomes. We tested this assumption using a mixed-methods experimental design manipulating psychological immersion. Thirty-nine randomly assigned first-year paramedicine students completed low- or high-environmental fidelity simulations [low-environmental fidelity simulations (LF(en)S) vs. high-environmental fidelity simulation (HF(en)S)] involving a manikin with obstructed airway (SimMan3G). Psychological immersion and cognitive burden were determined via continuous heart rate, eye tracking, self-report questionnaire (National Aeronautics and Space Administration Task Load Index), independent observation, and postsimulation interviews. Performance was assessed by successful location of obstruction and time-to-termination. Eye tracking confirmed that students attended to multiple, concurrent stimuli in HF(en)S and interviews consistently suggested that they experienced greater psychological immersion and cognitive burden than their LF(en)S counterparts. This was confirmed by significantly higher mean heart rate (P < 0.001) and National Aeronautics and Space Administration Task Load Index mental demand (P < 0.05). Although group allocation did not influence the proportion of students who ultimately revived the patient (58% vs. 30%, P < 0.10), the HF(en)S students did so significantly more quickly (P < 0.01). The LF(en)S students had low immersion resulting in greater assessment anxiety. High-environmental fidelity simulation engendered immersion and a sense of urgency in students, whereas LF(en)S created assessment anxiety and slower performance. We conclude that once early-stage students have learned the basics of a clinical skill, throwing them in the "deep end" of high-fidelity simulation creates significant additional cognitive burden but this has considerable educational merit.

Training for shoulder dystocia: a trial of simulation using low-fidelity and high-fidelity mannequins.

PubMed

Crofts, Joanna F; Bartlett, Christine; Ellis, Denise; Hunt, Linda P; Fox, Robert; Draycott, Timothy J

2006-12-01

To evaluate the effectiveness of simulation training for shoulder dystocia management and compare training using a high-fidelity mannequin with that using traditional devices. Training was undertaken in six hospitals and a medical simulation center in the United Kingdom. Midwives and obstetricians working for participating hospitals were eligible for inclusion. One hundred forty participants (45 doctors, 95 midwives) were randomized to training with a high-fidelity training mannequin (incorporating force perception training) or traditional low-fidelity mannequins. Performance was assessed pre- and posttraining, using a videoed, standardized shoulder dystocia simulation. Outcome measures were delivery, head-to-body delivery time, use of appropriate and inappropriate actions, force applied, and communication. One hundred thirty-two participants completed the posttraining assessment. All training was associated with improved performance: use of basic maneuvers 114 of 140 (81.4%) to 125 of 132 (94.7%) (P=.002), successful deliveries 60 of 140 (42.9%) to 110 of 132 (83.3%) (P<.001), good communication with the patient 79 of 139 (56.8%) to 109 of 132 (82.6%) (P<.001), pre- and posttraining, respectively. Training with the high-fidelity mannequin was associated with a higher successful delivery rate than training with traditional devices: 94% compared with 72% (odds ratio 6.53, 95% confidence interval 2.05-20.81; P=.002). Total applied force was significantly lower for those who had undergone force training (2,030 Newton seconds versus 2,916 Newton seconds; P=.006) but there was no significant difference in the peak applied force 102 Newtons versus 112 Newtons (P=.242). This study verifies the need for shoulder dystocia training; before training only 43% participants could achieve delivery. All training with mannequins improved the management of simulated shoulder dystocia. Training on a high-fidelity mannequin, including force perception teaching, offered additional training benefits. I.

Ecological correlates of mate fidelity in two Arctic-breeding sandpipers

USGS Publications Warehouse

Sandercock, Brett K.; Lank, David B.; Lanctot, Richard B.; Kempenaers, Bart; Cooke, Fred

2000-01-01

Monogamous birds exhibit considerable interspecific variation in rates of mate fidelity between years, but the reasons for this variation are still poorly understood. In a 4-year study carried out in western Alaska, mate-fidelity rates in Semipalmated Sandpipers (Calidris pusilla; mate fidelity was 47% among pairs where at least one mate returned and 94% among pairs where both mates returned) were substantially higher than in Western Sandpipers (Calidris mauri; 25 and 67%, respectively), despite the similar breeding biology of these sibling species. Divorce was not a response to nesting failure in Western Sandpipers, and mate change had no effect on the reproductive performance of either species. Nor were mate-fidelity rates related to differential rates of breeding dispersal, because the species did not differ in site fidelity. Reunited pairs and males that changed mates showed strong site tenacity, while females that changed mates moved farther. Differences in local survival rates or habitat are also unlikely to explain mate fidelity, since the two species did not differ in local survival rates, ϕ (Western Sandpipers: ϕ –hat = 0.57 ± 0.05 (mean ± SE), Semipalmated Sandpipers: ϕ –hat = 0.66 ± 0.06), and they bred in the same area, sometimes using the same nest cups. Although we were able to reject the above explanations, it was not possible to determine whether mate retention was lower in Western Sandpipers than in Semipalmated Sandpipers because of interspecific differences in mating tactics, time constraints imposed by migration distance, or a combination of these factors. Western Sandpipers exhibited greater sexual size dimorphism, but also migrated for shorter distances and tended to nest earlier and more asynchronously than Semipalmated Sandpipers. Finally, we show that conventional methods underestimate divorce rates, and interspecific comparisons may be biased if breeding-dispersal and recapture rates are not considered.

Multifidelity, Multidisciplinary Design Under Uncertainty with Non-Intrusive Polynomial Chaos

NASA Technical Reports Server (NTRS)

West, Thomas K., IV; Gumbert, Clyde

2017-01-01

The primary objective of this work is to develop an approach for multifidelity uncertainty quantification and to lay the framework for future design under uncertainty efforts. In this study, multifidelity is used to describe both the fidelity of the modeling of the physical systems, as well as the difference in the uncertainty in each of the models. For computational efficiency, a multifidelity surrogate modeling approach based on non-intrusive polynomial chaos using the point-collocation technique is developed for the treatment of both multifidelity modeling and multifidelity uncertainty modeling. Two stochastic model problems are used to demonstrate the developed methodologies: a transonic airfoil model and multidisciplinary aircraft analysis model. The results of both showed the multifidelity modeling approach was able to predict the output uncertainty predicted by the high-fidelity model as a significant reduction in computational cost.

Human dynamic orientation model applied to motion simulation. M.S. Thesis

NASA Technical Reports Server (NTRS)

Borah, J. D.

1976-01-01

The Ormsby model of dynamic orientation, in the form of a discrete time computer program was used to predict non-visually induced sensations during an idealized coordinated aircraft turn. To predict simulation fidelity, the Ormsby model was used to assign penalties for incorrect attitude and angular rate perceptions. It was determined that a three rotational degree of freedom simulation should remain faithful to attitude perception even at the expense of incorrect angular rate sensations. Implementing this strategy, a simulation profile for the idealized turn was designed for a Link GAT-1 trainer. A simple optokinetic display was added to improve the fidelity of roll rate sensations.

A high fidelity real-time simulation of a small turboshaft engine

NASA Technical Reports Server (NTRS)

Ballin, Mark G.

1988-01-01

A high-fidelity component-type model and real-time digital simulation of the General Electric T700-GE-700 turboshaft engine were developed for use with current generation real-time blade-element rotor helicopter simulations. A control system model based on the specification fuel control system used in the UH-60A Black Hawk helicopter is also presented. The modeling assumptions and real-time digital implementation methods particular to the simulation of small turboshaft engines are described. The validity of the simulation is demonstrated by comparison with analysis-oriented simulations developed by the manufacturer, available test data, and flight-test time histories.

Prospectus: towards the development of high-fidelity models of wall turbulence at large Reynolds number

PubMed Central

Klewicki, J. C.; Chini, G. P.; Gibson, J. F.

2017-01-01

Recent and on-going advances in mathematical methods and analysis techniques, coupled with the experimental and computational capacity to capture detailed flow structure at increasingly large Reynolds numbers, afford an unprecedented opportunity to develop realistic models of high Reynolds number turbulent wall-flow dynamics. A distinctive attribute of this new generation of models is their grounding in the Navier–Stokes equations. By adhering to this challenging constraint, high-fidelity models ultimately can be developed that not only predict flow properties at high Reynolds numbers, but that possess a mathematical structure that faithfully captures the underlying flow physics. These first-principles models are needed, for example, to reliably manipulate flow behaviours at extreme Reynolds numbers. This theme issue of Philosophical Transactions of the Royal Society A provides a selection of contributions from the community of researchers who are working towards the development of such models. Broadly speaking, the research topics represented herein report on dynamical structure, mechanisms and transport; scale interactions and self-similarity; model reductions that restrict nonlinear interactions; and modern asymptotic theories. In this prospectus, the challenges associated with modelling turbulent wall-flows at large Reynolds numbers are briefly outlined, and the connections between the contributing papers are highlighted. This article is part of the themed issue ‘Toward the development of high-fidelity models of wall turbulence at large Reynolds number’. PMID:28167585

Prospectus: towards the development of high-fidelity models of wall turbulence at large Reynolds number.

PubMed

Klewicki, J C; Chini, G P; Gibson, J F

2017-03-13

Recent and on-going advances in mathematical methods and analysis techniques, coupled with the experimental and computational capacity to capture detailed flow structure at increasingly large Reynolds numbers, afford an unprecedented opportunity to develop realistic models of high Reynolds number turbulent wall-flow dynamics. A distinctive attribute of this new generation of models is their grounding in the Navier-Stokes equations. By adhering to this challenging constraint, high-fidelity models ultimately can be developed that not only predict flow properties at high Reynolds numbers, but that possess a mathematical structure that faithfully captures the underlying flow physics. These first-principles models are needed, for example, to reliably manipulate flow behaviours at extreme Reynolds numbers. This theme issue of Philosophical Transactions of the Royal Society A provides a selection of contributions from the community of researchers who are working towards the development of such models. Broadly speaking, the research topics represented herein report on dynamical structure, mechanisms and transport; scale interactions and self-similarity; model reductions that restrict nonlinear interactions; and modern asymptotic theories. In this prospectus, the challenges associated with modelling turbulent wall-flows at large Reynolds numbers are briefly outlined, and the connections between the contributing papers are highlighted.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).

Implementing a Primary Prevention Social Skills Intervention in Urban Preschools: Factors Associated with Quality and Fidelity

PubMed Central

Wenz-Gross, Melodie; Upshur, Carole

2012-01-01

Research Findings Preschool behavior problems are of increasing concern to early childhood educators. Preventive interventions are being developed, but implementation in under-resourced child care programs is challenging. This study describes the implementation of an adapted Second Step curriculum to increase children’s social skills and decrease behavior problems in preschool classrooms. Teacher training/coaching, organizational supports, and procedures for sustainability are described. Measures included baseline classroom characteristics, lesson completion and fidelity, and teacher satisfaction. Teachers completed 88% of the lessons across two years. Follow-up monitoring in Year 3, once all training was terminated, found 95% of lessons were delivered with higher fidelity than the first two years. Teachers were satisfied with training, felt the curriculum improved children’s social skills, and stated they would continue to use the curriculum. Lesson completion and fidelity were associated with various teacher characteristics, training attendance, classroom characteristics, teacher and child turnover, and the percent of children with developmental delays in the classroom. Practice Results support the implementation strategy and suggest that paying attention to teacher morale, general skill development, and a period of on-going support for training is important and will lead to sustainable and high implementation rates. PMID:22791957

Fidelity of Implementation in Project Towards No Drug Abuse (TND): A Comparison of Classroom Teachers and Program Specialists

PubMed Central

Dent, Clyde W.; Skara, Silvana; Sun, Ping; Sussman, Steve

2011-01-01

This paper presents the results of an effectiveness trial of Project Towards No Drug Abuse [TND], in which we compared program delivery by regular classroom teachers and program specialists within the same high schools. Within 18 schools that were randomly assigned to the program or control conditions, health classrooms were assigned to program delivery by teachers or (outside) specialists. Classroom sessions were observed by pairs of observers to assess three domains of implementation fidelity: adherence, classroom process, and perceived student acceptance of the program. Pre- and immediate posttest survey data were collected from 2331 students. Of the four composite indexes of implementation fidelity that were examined, only one (quality of delivery) showed a difference between specialists and teachers, with marginally higher ratings of specialists (p < .10). Both teachers and program specialists achieved effects on three of the five immediate outcome measures, including program-specific knowledge, addiction concern, and social self-control. Students’ posttest ratings of the program overall and the quality of program delivery failed to reveal differences between the teacher- and specialist-led classrooms. These results suggest that motivated, trained classroom teachers can implement evidence-based prevention programs with fidelity and achieve immediate effects. PMID:17180722

Assessing the Implementation Fidelity of a School-Based Teaching Personal and Social Responsibility Program in Physical Education and Other Subject Areas

ERIC Educational Resources Information Center

Escartí, Amparo; Liops-Goig, Ramon; Wright, Paul M.

2018-01-01

Purpose: The Teaching Personal and Social Responsibility (TPSR) model was developed to foster responsibility and teach life skills that transfer to various settings. The purpose of this study was to assess the implementation fidelity of a school-based TPSR program in physical education and other subject areas. Method: Systematic observation was…

Evidence-Based Programming within Cooperative Extension: How Can We Maintain Program Fidelity While Adapting to Meet Local Needs?

ERIC Educational Resources Information Center

Olson, Jonathan R.; Welsh, Janet A.; Perkins, Daniel F.

2015-01-01

In this article, we describe how the recent movement towards evidence-based programming has impacted Extension. We review how the emphasis on implementing such programs with strict fidelity to an underlying program model may be at odds with Extension's strong history of adapting programming to meet the unique needs of children, youth, families,…

Validation of Survivability Validation Protocols

DTIC Science & Technology

1993-05-01

simu- lation fidelityl. Physical testing of P.i SOS, in either aboveground tests (AGTs) or underground test ( UGTs ), will usually be impossible, due...with some simulation fidelity compromises) are possible in UGTs and/orAGTs. Hence proof tests, if done in statistically significant numbers, can...level. Simulation fidelity and AGT/ UGT /threat correlation will be validation issues here. Extrapolation to threat environments will be done via modeling

An experimental study on the effects of a simulation game on students' clinical cognitive skills and motivation.

PubMed

Dankbaar, Mary E W; Alsma, Jelmer; Jansen, Els E H; van Merrienboer, Jeroen J G; van Saase, Jan L C M; Schuit, Stephanie C E

2016-08-01

Simulation games are becoming increasingly popular in education, but more insight in their critical design features is needed. This study investigated the effects of fidelity of open patient cases in adjunct to an instructional e-module on students' cognitive skills and motivation. We set up a three-group randomized post-test-only design: a control group working on an e-module; a cases group, combining the e-module with low-fidelity text-based patient cases, and a game group, combining the e-module with a high-fidelity simulation game with the same cases. Participants completed questionnaires on cognitive load and motivation. After a 4-week study period, blinded assessors rated students' cognitive emergency care skills in two mannequin-based scenarios. In total 61 students participated and were assessed; 16 control group students, 20 cases students and 25 game students. Learning time was 2 h longer for the cases and game groups than for the control group. Acquired cognitive skills did not differ between groups. The game group experienced higher intrinsic and germane cognitive load than the cases group (p = 0.03 and 0.01) and felt more engaged (p < 0.001). Students did not profit from working on open cases (in adjunct to an e-module), which nonetheless challenged them to study longer. The e-module appeared to be very effective, while the high-fidelity game, although engaging, probably distracted students and impeded learning. Medical educators designing motivating and effective skills training for novices should align case complexity and fidelity with students' proficiency level. The relation between case-fidelity, motivation and skills development is an important field for further study.

Mate fidelity and breeding site tenacity in a monogamous sandpiper, the black turnstone

USGS Publications Warehouse

Handel, Colleen M.; Gill, Robert E.

2000-01-01

We examined the relationship between mate fidelity and breeding site tenacity during a 5-year study of the black turnstone, Arenaria melanocephala, a socially monogamous sandpiper breeding in subarctic Alaska. We tested the predictions of several hypotheses regarding the incidence of divorce and the benefits of fidelity to mate and breeding site. Interannual return rates to the breeding grounds (88% for males, 79% for females) were among the highest yet recorded for any scolopacid sandpiper, and 88% of returning birds nested on their previous year's territory. The annual divorce rate was only 11%, and mate fidelity was significantly linked to fidelity to territory but independent of sex and year. Males arrived in spring significantly earlier than their mates and interannual fidelity was influenced by the relative timing of arrival of pair members. Reunited pairs had significantly higher fledging success than new pairs formed after death or divorce. The incidence of divorce was unrelated to reproductive success the previous year, although birds nested significantly further away after failure than after a successful nesting attempt. Sightings of marked individuals suggested that members of pairs do not winter together, and breeding site tenacity provides a mechanism through which pair members can reunite. We reject the 'incompatibility' hypothesis for divorce in turnstones, and our data contradict predictions of the 'better option' hypothesis. Alternatively, we propose the 'bet-hedging' hypothesis to explain the occurrence of divorce, which transpires when an individual pairs with a new mate to avoid the cost of waiting for a previous mate to return. Such costs can include remaining unmated, if the former mate has died, or experiencing lower reproductive success because of delayed breeding.

Conceptual design and analysis of a dynamic scale model of the Space Station Freedom

NASA Technical Reports Server (NTRS)

Davis, D. A.; Gronet, M. J.; Tan, M. K.; Thorne, J.

1994-01-01

This report documents the conceptual design study performed to evaluate design options for a subscale dynamic test model which could be used to investigate the expected on-orbit structural dynamic characteristics of the Space Station Freedom early build configurations. The baseline option was a 'near-replica' model of the SSF SC-7 pre-integrated truss configuration. The approach used to develop conceptual design options involved three sets of studies: evaluation of the full-scale design and analysis databases, conducting scale factor trade studies, and performing design sensitivity studies. The scale factor trade study was conducted to develop a fundamental understanding of the key scaling parameters that drive design, performance and cost of a SSF dynamic scale model. Four scale model options were estimated: 1/4, 1/5, 1/7, and 1/10 scale. Prototype hardware was fabricated to assess producibility issues. Based on the results of the study, a 1/4-scale size is recommended based on the increased model fidelity associated with a larger scale factor. A design sensitivity study was performed to identify critical hardware component properties that drive dynamic performance. A total of 118 component properties were identified which require high-fidelity replication. Lower fidelity dynamic similarity scaling can be used for non-critical components.

Neural network submodel as an abstraction tool: relating network performance to combat outcome

NASA Astrophysics Data System (ADS)

Jablunovsky, Greg; Dorman, Clark; Yaworsky, Paul S.

2000-06-01

Simulation of Command and Control (C2) networks has historically emphasized individual system performance with little architectural context or credible linkage to `bottom- line' measures of combat outcomes. Renewed interest in modeling C2 effects and relationships stems from emerging network intensive operational concepts. This demands improved methods to span the analytical hierarchy between C2 system performance models and theater-level models. Neural network technology offers a modeling approach that can abstract the essential behavior of higher resolution C2 models within a campaign simulation. The proposed methodology uses off-line learning of the relationships between network state and campaign-impacting performance of a complex C2 architecture and then approximation of that performance as a time-varying parameter in an aggregated simulation. Ultimately, this abstraction tool offers an increased fidelity of C2 system simulation that captures dynamic network dependencies within a campaign context.

Detailed Measurement of ORSC Main Chamber Injector Dynamics

NASA Astrophysics Data System (ADS)

Bedard, Michael J.

Improving fidelity in simulation of combustion dynamics in rocket combustors requires an increase in experimental measurement fidelity for validation. In a model rocket combustor, a chemiluminescence based spectroscopy technique was used to capture flame light emissions for direct comparison to a computational simulation of the production of chemiluminescent species. The comparison indicated that high fidelity models of rocket combustors can predict spatio-temporal distribution of chemiluminescent species with trend-wise accuracy. The comparison also indicated the limited ability of OH* and CH* emission to indicate flame heat release. Based on initial spectroscopy experiments, a photomultiplier based chemiluminescence sensor was designed to increase the temporal resolution of flame emission measurements. To apply developed methodologies, an experiment was designed to investigate the flow and combustion dynamics associated with main chamber injector elements typical of the RD-170 rocket engine. A unique feature of the RD-170 injector element is the beveled expansion between the injector recess and combustion chamber. To investigate effects of this geometry, a scaling methodology was applied to increase the physical scale of a single injector element while maintaining traceability to the RD-170 design. Two injector configurations were tested, one including a beveled injector face and the other a flat injector face. This design enabled improved spatial resolution of pressure and light emission measurements densely arranged in the injector recess and near-injector region of the chamber. Experimental boundary conditions were designed to closely replicate boundary conditions in simulations. Experimental results showed that the beveled injector face had a damping effect on pressure fluctuations occurring near the longitudinal resonant acoustic modes of the chamber, implying a mechanism for improved overall combustion stability. Near the injector, the beveled geometry resulted in more acoustic energy into higher frequency modes, while the flat-face geometry excited modes closer to the fundamental longitudinal mode frequency and its harmonics. Multi-scale analysis techniques were used to investigate intermittency and the range of physical scales present in measured signals. Flame light emission measurements confirmed the presence of flame holding in the injector recess in both configurations. Analysis of dynamics in light emission signals showed flame response at the chamber acoustic resonance frequency in addition to non-acoustic modes associated with mixing shear layer dynamics in the injector recess. The first known benchmark quality data sets of such injector dynamics were recorded in each configuration to enable pressure-based validation of high fidelity models of gas-centered swirl coaxial injectors. This work presents a critical contribution to development of validated combustion dynamics predictive tools and to the understanding of gas-centered swirl coaxial injector elements.

Computational Fluid Dynamic Investigation of Loss Mechanisms in a Pulse-Tube Refrigerator

NASA Astrophysics Data System (ADS)

Martin, K.; Esguerra, J.; Dodson, C.; Razani, A.

2015-12-01

In predicting Pulse-Tube Cryocooler (PTC) performance, One-Dimensional (1-D) PTR design and analysis tools such as Gedeon Associates SAGE® typically include models for performance degradation due to thermodynamically irreversible processes. SAGE®, in particular, accounts for convective loss, turbulent conductive loss and numerical diffusion “loss” via correlation functions based on analysis and empirical testing. In this study, we compare CFD and SAGE® estimates of PTR refrigeration performance for four distinct pulse-tube lengths. Performance predictions from PTR CFD models are compared to SAGE® predictions for all four cases. Then, to further demonstrate the benefits of higher-fidelity and multidimensional CFD simulation, the PTR loss mechanisms are characterized in terms of their spatial and temporal locations.

Information theoretic approach for assessing image fidelity in photon-counting arrays.

PubMed

Narravula, Srikanth R; Hayat, Majeed M; Javidi, Bahram

2010-02-01

The method of photon-counting integral imaging has been introduced recently for three-dimensional object sensing, visualization, recognition and classification of scenes under photon-starved conditions. This paper presents an information-theoretic model for the photon-counting imaging (PCI) method, thereby providing a rigorous foundation for the merits of PCI in terms of image fidelity. This, in turn, can facilitate our understanding of the demonstrated success of photon-counting integral imaging in compressive imaging and classification. The mutual information between the source and photon-counted images is derived in a Markov random field setting and normalized by the source-image's entropy, yielding a fidelity metric that is between zero and unity, which respectively corresponds to complete loss of information and full preservation of information. Calculations suggest that the PCI fidelity metric increases with spatial correlation in source image, from which we infer that the PCI method is particularly effective for source images with high spatial correlation; the metric also increases with the reduction in photon-number uncertainty. As an application to the theory, an image-classification problem is considered showing a congruous relationship between the fidelity metric and classifier's performance.

The mechanism of untargeted mutagenesis in UV-irradiated yeast.

PubMed

Lawrence, C W; Christensen, R B

1982-01-01

The SOS error-prone repair hypothesis proposes that untargeted and targeted mutations in E. coli both result from the inhibition of polymerase functions that normally maintain fidelity, and that this is a necessary precondition for translesion synthesis. Using mating experiments with excision deficient strains of Bakers' yeast, Saccharomyces cerevisiae, we find that up to 40% of cycl-91 revertants induced by UV are untargeted, showing that a reduction in fidelity is also found in irradiated cells of this organism. We are, however, unable to detect the induction or activation of any diffusible factor capable of inhibiting fidelity, and therefore suggest that untargeted and targeted mutations are the consequence of largely different processes. We propose that these observations are best explained in terms of a limited fidelity model. Untargeted mutations are thought to result from the limited capacity of processes which normally maintain fidelity, which are active during replication on both irradiated and unirradiated templates. Even moderate UV fluences saturate this capacity, leading to competition for the limited resource. Targeted mutations are believed to result from the limited, though far from negligible, capacity of lesions like pyrimidine dimers to form Watson-Crick base pairs.

Variable fidelity robust optimization of pulsed laser orbital debris removal under epistemic uncertainty

NASA Astrophysics Data System (ADS)

Hou, Liqiang; Cai, Yuanli; Liu, Jin; Hou, Chongyuan

2016-04-01

A variable fidelity robust optimization method for pulsed laser orbital debris removal (LODR) under uncertainty is proposed. Dempster-shafer theory of evidence (DST), which merges interval-based and probabilistic uncertainty modeling, is used in the robust optimization. The robust optimization method optimizes the performance while at the same time maximizing its belief value. A population based multi-objective optimization (MOO) algorithm based on a steepest descent like strategy with proper orthogonal decomposition (POD) is used to search robust Pareto solutions. Analytical and numerical lifetime predictors are used to evaluate the debris lifetime after the laser pulses. Trust region based fidelity management is designed to reduce the computational cost caused by the expensive model. When the solutions fall into the trust region, the analytical model is used to reduce the computational cost. The proposed robust optimization method is first tested on a set of standard problems and then applied to the removal of Iridium 33 with pulsed lasers. It will be shown that the proposed approach can identify the most robust solutions with minimum lifetime under uncertainty.

Multi-Compartmentalisation in the MAPK Signalling Pathway Contributes to the Emergence of Oscillatory Behaviour and to Ultrasensitivity

PubMed Central

Shuaib, Aban; Hartwell, Adam; Kiss-Toth, Endre; Holcombe, Mike

2016-01-01

Signal transduction through the Mitogen Activated Protein Kinase (MAPK) pathways is evolutionarily highly conserved. Many cells use these pathways to interpret changes to their environment and respond accordingly. The pathways are central to triggering diverse cellular responses such as survival, apoptosis, differentiation and proliferation. Though the interactions between the different MAPK pathways are complex, nevertheless, they maintain a high level of fidelity and specificity to the original signal. There are numerous theories explaining how fidelity and specificity arise within this complex context; spatio-temporal regulation of the pathways and feedback loops are thought to be very important. This paper presents an agent based computational model addressing multi-compartmentalisation and how this influences the dynamics of MAPK cascade activation. The model suggests that multi-compartmentalisation coupled with periodic MAPK kinase (MAPKK) activation may be critical factors for the emergence of oscillation and ultrasensitivity in the system. Finally, the model also establishes a link between the spatial arrangements of the cascade components and temporal activation mechanisms, and how both contribute to fidelity and specificity of MAPK mediated signalling. PMID:27243235

High Fidelity BWR Fuel Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, Su Jong

This report describes the Consortium for Advanced Simulation of Light Water Reactors (CASL) work conducted for completion of the Thermal Hydraulics Methods (THM) Level 3 milestone THM.CFD.P13.03: High Fidelity BWR Fuel Simulation. High fidelity computational fluid dynamics (CFD) simulation for Boiling Water Reactor (BWR) was conducted to investigate the applicability and robustness performance of BWR closures. As a preliminary study, a CFD model with simplified Ferrule spacer grid geometry of NUPEC BWR Full-size Fine-mesh Bundle Test (BFBT) benchmark has been implemented. Performance of multiphase segregated solver with baseline boiling closures has been evaluated. Although the mean values of void fractionmore » and exit quality of CFD result for BFBT case 4101-61 agreed with experimental data, the local void distribution was not predicted accurately. The mesh quality was one of the critical factors to obtain converged result. The stability and robustness of the simulation was mainly affected by the mesh quality, combination of BWR closure models. In addition, the CFD modeling of fully-detailed spacer grid geometry with mixing vane is necessary for improving the accuracy of CFD simulation.« less

Model inversion via multi-fidelity Bayesian optimization: a new paradigm for parameter estimation in haemodynamics, and beyond.

PubMed

Perdikaris, Paris; Karniadakis, George Em

2016-05-01

We present a computational framework for model inversion based on multi-fidelity information fusion and Bayesian optimization. The proposed methodology targets the accurate construction of response surfaces in parameter space, and the efficient pursuit to identify global optima while keeping the number of expensive function evaluations at a minimum. We train families of correlated surrogates on available data using Gaussian processes and auto-regressive stochastic schemes, and exploit the resulting predictive posterior distributions within a Bayesian optimization setting. This enables a smart adaptive sampling procedure that uses the predictive posterior variance to balance the exploration versus exploitation trade-off, and is a key enabler for practical computations under limited budgets. The effectiveness of the proposed framework is tested on three parameter estimation problems. The first two involve the calibration of outflow boundary conditions of blood flow simulations in arterial bifurcations using multi-fidelity realizations of one- and three-dimensional models, whereas the last one aims to identify the forcing term that generated a particular solution to an elliptic partial differential equation. © 2016 The Author(s).

Model inversion via multi-fidelity Bayesian optimization: a new paradigm for parameter estimation in haemodynamics, and beyond

PubMed Central

Perdikaris, Paris; Karniadakis, George Em

2016-01-01

We present a computational framework for model inversion based on multi-fidelity information fusion and Bayesian optimization. The proposed methodology targets the accurate construction of response surfaces in parameter space, and the efficient pursuit to identify global optima while keeping the number of expensive function evaluations at a minimum. We train families of correlated surrogates on available data using Gaussian processes and auto-regressive stochastic schemes, and exploit the resulting predictive posterior distributions within a Bayesian optimization setting. This enables a smart adaptive sampling procedure that uses the predictive posterior variance to balance the exploration versus exploitation trade-off, and is a key enabler for practical computations under limited budgets. The effectiveness of the proposed framework is tested on three parameter estimation problems. The first two involve the calibration of outflow boundary conditions of blood flow simulations in arterial bifurcations using multi-fidelity realizations of one- and three-dimensional models, whereas the last one aims to identify the forcing term that generated a particular solution to an elliptic partial differential equation. PMID:27194481

High-Fidelity Flash Lidar Model Development

NASA Technical Reports Server (NTRS)

Hines, Glenn D.; Pierrottet, Diego F.; Amzajerdian, Farzin

2014-01-01

NASA's Autonomous Landing and Hazard Avoidance Technologies (ALHAT) project is currently developing the critical technologies to safely and precisely navigate and land crew, cargo and robotic spacecraft vehicles on and around planetary bodies. One key element of this project is a high-fidelity Flash Lidar sensor that can generate three-dimensional (3-D) images of the planetary surface. These images are processed with hazard detection and avoidance and hazard relative navigation algorithms, and then are subsequently used by the Guidance, Navigation and Control subsystem to generate an optimal navigation solution. A complex, high-fidelity model of the Flash Lidar was developed in order to evaluate the performance of the sensor and its interaction with the interfacing ALHAT components on vehicles with different configurations and under different flight trajectories. The model contains a parameterized, general approach to Flash Lidar detection and reflects physical attributes such as range and electronic noise sources, and laser pulse temporal and spatial profiles. It also provides the realistic interaction of the laser pulse with terrain features that include varying albedo, boulders, craters slopes and shadows. This paper gives a description of the Flash Lidar model and presents results from the Lidar operating under different scenarios.

Thermodynamic Basis for the Emergence of Genomes during Prebiotic Evolution

PubMed Central

Woo, Hyung-June; Vijaya Satya, Ravi; Reifman, Jaques

2012-01-01

The RNA world hypothesis views modern organisms as descendants of RNA molecules. The earliest RNA molecules must have been random sequences, from which the first genomes that coded for polymerase ribozymes emerged. The quasispecies theory by Eigen predicts the existence of an error threshold limiting genomic stability during such transitions, but does not address the spontaneity of changes. Following a recent theoretical approach, we applied the quasispecies theory combined with kinetic/thermodynamic descriptions of RNA replication to analyze the collective behavior of RNA replicators based on known experimental kinetics data. We find that, with increasing fidelity (relative rate of base-extension for Watson-Crick versus mismatched base pairs), replications without enzymes, with ribozymes, and with protein-based polymerases are above, near, and below a critical point, respectively. The prebiotic evolution therefore must have crossed this critical region. Over large regions of the phase diagram, fitness increases with increasing fidelity, biasing random drifts in sequence space toward ‘crystallization.’ This region encloses the experimental nonenzymatic fidelity value, favoring evolutions toward polymerase sequences with ever higher fidelity, despite error rates above the error catastrophe threshold. Our work shows that experimentally characterized kinetics and thermodynamics of RNA replication allow us to determine the physicochemical conditions required for the spontaneous crystallization of biological information. Our findings also suggest that among many potential oligomers capable of templated replication, RNAs may have evolved to form prebiotic genomes due to the value of their nonenzymatic fidelity. PMID:22693440

Just-in-Time Teaching in undergraduate physics courses: Implementation, learning, and perceptions

NASA Astrophysics Data System (ADS)

Dwyer, Jessica Hewitt

Regardless of discipline, a decades-long battle has ensued within nearly every classroom in higher education: instructors getting students to come to class prepared to learn. In response to this clash between teacher expectations and frequent student neglect, a group of four physics education researchers developed a reformed instructional strategy called Just-in-Time Teaching (JiTT). This dissertation investigates the following three areas: 1) the fidelity with which undergraduate physics instructors implement JiTT, 2) whether student performance predicts student perception of their instructor's fidelity of JiTT implementation, and 3) whether student perception of their instructor's fidelity of JiTT implementation correlates with student views of their physics course. A blend of quantitative data (e.g., students grades, inventory scores, and questionnaire responses) are integrated with qualitative data (e.g., individual faculty interviews, student focus group discussions, and classroom observations). This study revealed no statistically significant relationship between instructors who spent time on a predefined JiTT critical component and their designation as a JiTT user or non-user. While JiTT users implemented the pedagogy in accordance with the creators' intended ideal vision, many also had trouble reconciling personal concerns about their role as a JiTT adopter and the anticipated demand of the innovation. I recommend that this population of faculty members can serve as a JiTT model for other courses, disciplines, and/or institutions. Student performance was not a predictor of student perception instructor fidelity of JiTT implementation. Additionally, the majority of students in this study reported they read their textbook prior to class and that JiTT assignments helped them prepare for in-class learning. I found evidence that exposure to the JiTT strategy may correlate with a more favorable student view of their physics course. Finally, according to students, favorable JiTT implementation occurred when instructors reviewed all questions contained within the JiTT assignment during class and when instructors clearly connected JiTT questions to the textbook reading, lesson discussion, and other assignments. The impact of this work rests in its possibility to set the stage for future education studies on the fidelity of implementation of other research-based instructional strategies in various disciplines and how they affect student performance and perceptions.

WE-FG-207B-02: Material Reconstruction for Spectral Computed Tomography with Detector Response Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, J; Gao, H

2016-06-15

Purpose: Different from the conventional computed tomography (CT), spectral CT based on energy-resolved photon-counting detectors is able to provide the unprecedented material composition. However, an important missing piece for accurate spectral CT is to incorporate the detector response function (DRF), which is distorted by factors such as pulse pileup and charge-sharing. In this work, we propose material reconstruction methods for spectral CT with DRF. Methods: The polyenergetic X-ray forward model takes the DRF into account for accurate material reconstruction. Two image reconstruction methods are proposed: a direct method based on the nonlinear data fidelity from DRF-based forward model; a linear-data-fidelitymore » based method that relies on the spectral rebinning so that the corresponding DRF matrix is invertible. Then the image reconstruction problem is regularized with the isotropic TV term and solved by alternating direction method of multipliers. Results: The simulation results suggest that the proposed methods provided more accurate material compositions than the standard method without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Conclusion: We have proposed material reconstruction methods for spectral CT with DRF, whichprovided more accurate material compositions than the standard methods without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Jiulong Liu and Hao Gao were partially supported by the NSFC (#11405105), the 973 Program (#2015CB856000), and the Shanghai Pujiang Talent Program (#14PJ1404500).« less

Implementation of integrated dual disorders treatment: a qualitative analysis of facilitators and barriers.

PubMed

Brunette, Mary F; Asher, Dianne; Whitley, Rob; Lutz, Wilma J; Wieder, Barbara L; Jones, Amanda M; McHugo, Gregory J

2008-09-01

Approximately half of the people who have serious mental illnesses experience a co-occurring substance use disorder at some point in their lifetime. Integrated dual disorders treatment, a program to treat persons with co-occurring disorders, improves outcomes but is not widely available in public mental health settings. This report describes the extent to which this intervention was implemented by 11 community mental health centers participating in a large study of practice implementation. Facilitators and barriers to implementation are described. Trained implementation monitors conducted regular site visits over two years. During visits, monitors interviewed key informants, conducted ethnographic observations of implementation efforts, and assessed fidelity to the practice model. These data were coded and used as a basis for detailed site reports summarizing implementation processes. The authors reviewed the reports and distilled the three top facilitators and barriers for each site. The most prominent cross-site facilitators and barriers were identified. Two sites reached high fidelity, six sites reached moderate fidelity, and three sites remained at low fidelity over the two years. Prominent facilitators and barriers to implementation with moderate to high fidelity were administrative leadership, consultation and training, supervisor mastery and supervision, chronic staff turnover, and finances. Common facilitators and barriers to implementation of integrated dual disorders treatment emerged across sites. The results confirmed the importance of the use of the consultant-trainer in the model of implementation, as well as the need for intensive activities at multiple levels to facilitate implementation. Further research on service implementation is needed, including but not limited to clarifying strategies to overcome barriers.

Heterogeneous oxygen availability affects the titer and topology but not the fidelity of plasmid DNA produced by Escherichia coli.

PubMed

Jaén, Karim E; Sigala, Juan-Carlos; Olivares-Hernández, Roberto; Niehaus, Karsten; Lara, Alvaro R

2017-07-04

Dissolved oxygen tension (DOT) is hardly constant and homogenously distributed in a bioreactor, which can have a negative impact in the metabolism and product synthesis. However, the effects of DOT on plasmid DNA (pDNA) production and quality have not been thoroughly investigated. In the present study, the effects of aerobic (DOT ≥30% air sat.), microaerobic (constant DOT = 3% air sat.) and oscillatory DOT (from 0 to 100% air sat.) conditions on pDNA production, quality and host performance were characterized. Microaerobic conditions had little effect on pDNA production, supercoiled fraction and sequence fidelity. By contrast, oscillatory DOT caused a 22% decrease in pDNA production compared with aerobic cultures. Although in aerobic cultures the pDNA supercoiled fraction was 98%, it decreased to 80% under heterogeneous DOT conditions. The different oxygen availabilities had no effect on the fidelity of the produced pDNA. The estimated metabolic fluxes indicated substantial differences at the level of the pentose phosphate pathway and TCA cycle under different conditions. Cyclic changes in fermentative pathway fluxes, as well as fast shifts in the fluxes through cytochromes, were also estimated. Model-based genetic modifications that can potentially improve the process performance are suggested. DOT heterogeneities strongly affected cell performance, pDNA production and topology. This should be considered when operating or scaling-up a bioreactor with deficient mixing. Constant microaerobic conditions affected the bacterial metabolism but not the amount or quality of pDNA. Therefore, pDNA production in microaerobic cultures may be an alternative for bioreactor operation at higher oxygen transfer rates.

Measuring partner choice in plant-pollinator networks: using null models to separate rewiring and fidelity from chance.

PubMed

MacLeod, Molly; Genung, Mark A; Ascher, John S; Winfree, Rachael

2016-11-01

Recent studies of mutualistic networks show that interactions between partners change across years. Both biological mechanisms and chance could drive these patterns, but the relative importance of these factors has not been separated. We established a field experiment consisting of 102 monospecific plots of 17 native plant species, from which we collected 6713 specimens of 52 bee species over four years. We used these data and a null model to determine whether bee species' foraging choices varied more or less over time beyond the variation expected by chance. Thus we provide the first quantitative definition of rewiring and fidelity as these terms are used in the literature on interaction networks. All 52 bee species varied in plant partner choice across years, but for 27 species this variation was indistinguishable from random partner choice. Another 11 species showed rewiring, varying more across years than expected by chance, while 14 species showed fidelity, indicating that they both prefer certain plant species and are consistent in those preferences across years. Our study shows that rewiring and fidelity both exist in mutualist networks, but that once sampling effects have been accounted for, they are less common than has been reported in the ecological literature. © 2016 by the Ecological Society of America.

Multi-fidelity uncertainty quantification in large-scale predictive simulations of turbulent flow

NASA Astrophysics Data System (ADS)

Geraci, Gianluca; Jofre-Cruanyes, Lluis; Iaccarino, Gianluca

2017-11-01

The performance characterization of complex engineering systems often relies on accurate, but computationally intensive numerical simulations. It is also well recognized that in order to obtain a reliable numerical prediction the propagation of uncertainties needs to be included. Therefore, Uncertainty Quantification (UQ) plays a fundamental role in building confidence in predictive science. Despite the great improvement in recent years, even the more advanced UQ algorithms are still limited to fairly simplified applications and only moderate parameter dimensionality. Moreover, in the case of extremely large dimensionality, sampling methods, i.e. Monte Carlo (MC) based approaches, appear to be the only viable alternative. In this talk we describe and compare a family of approaches which aim to accelerate the convergence of standard MC simulations. These methods are based on hierarchies of generalized numerical resolutions (multi-level) or model fidelities (multi-fidelity), and attempt to leverage the correlation between Low- and High-Fidelity (HF) models to obtain a more accurate statistical estimator without introducing additional HF realizations. The performance of these methods are assessed on an irradiated particle laden turbulent flow (PSAAP II solar energy receiver). This investigation was funded by the United States Department of Energy's (DoE) National Nuclear Security Administration (NNSA) under the Predicitive Science Academic Alliance Program (PSAAP) II at Stanford University.

Modeling human pilot cue utilization with applications to simulator fidelity assessment.

PubMed

Zeyada, Y; Hess, R A

2000-01-01

An analytical investigation to model the manner in which pilots perceive and utilize visual, proprioceptive, and vestibular cues in a ground-based flight simulator was undertaken. Data from a NASA Ames Research Center vertical motion simulator study of a simple, single-degree-of-freedom rotorcraft bob-up/down maneuver were employed in the investigation. The study was part of a larger research effort that has the creation of a methodology for determining flight simulator fidelity requirements as its ultimate goal. The study utilized a closed-loop feedback structure of the pilot/simulator system that included the pilot, the cockpit inceptor, the dynamics of the simulated vehicle, and the motion system. With the exception of time delays that accrued in visual scene production in the simulator, visual scene effects were not included in this study. Pilot/vehicle analysis and fuzzy-inference identification were employed to study the changes in fidelity that occurred as the characteristics of the motion system were varied over five configurations. The data from three of the five pilots who participated in the experimental study were analyzed in the fuzzy-inference identification. Results indicate that both the analytical pilot/vehicle analysis and the fuzzy-inference identification can be used to identify changes in simulator fidelity for the task examined.

Vestibular models for design and evaluation of flight simulator motion

NASA Technical Reports Server (NTRS)

Bussolari, S. R.; Sullivan, R. B.; Young, L. R.

1986-01-01

The use of spatial orientation models in the design and evaluation of control systems for motion-base flight simulators is investigated experimentally. The development of a high-fidelity motion drive controller using an optimal control approach based on human vestibular models is described. The formulation and implementation of the optimal washout system are discussed. The effectiveness of the motion washout system was evaluated by studying the response of six motion washout systems to the NASA/AMES Vertical Motion Simulator for a single dash-quick-stop maneuver. The effects of the motion washout system on pilot performance and simulator acceptability are examined. The data reveal that human spatial orientation models are useful for the design and evaluation of flight simulator motion fidelity.

Incorporating Non-Linear Sorption into High Fidelity Subsurface Reactive Transport Models

NASA Astrophysics Data System (ADS)

Matott, L. S.; Rabideau, A. J.; Allen-King, R. M.

2014-12-01

A variety of studies, including multiple NRC (National Research Council) reports, have stressed the need for simulation models that can provide realistic predictions of contaminant behavior during the groundwater remediation process, most recently highlighting the specific technical challenges of "back diffusion and desorption in plume models". For a typically-sized remediation site, a minimum of about 70 million grid cells are required to achieve desired cm-level thickness among low-permeability lenses responsible for driving the back-diffusion phenomena. Such discretization is nearly three orders of magnitude more than is typically seen in modeling practice using public domain codes like RT3D (Reactive Transport in Three Dimensions). Consequently, various extensions have been made to the RT3D code to support efficient modeling of recently proposed dual-mode non-linear sorption processes (e.g. Polanyi with linear partitioning) at high-fidelity scales of grid resolution. These extensions have facilitated development of exploratory models in which contaminants are introduced into an aquifer via an extended multi-decade "release period" and allowed to migrate under natural conditions for centuries. These realistic simulations of contaminant loading and migration provide high fidelity representation of the underlying diffusion and sorption processes that control remediation. Coupling such models with decision support processes is expected to facilitate improved long-term management of complex remediation sites that have proven intractable to conventional remediation strategies.

The dynamics of fidelity over the time course of long-term memory.

PubMed

Persaud, Kimele; Hemmer, Pernille

2016-08-01

Bayesian models of cognition assume that prior knowledge about the world influences judgments. Recent approaches have suggested that the loss of fidelity from working to long-term (LT) memory is simply due to an increased rate of guessing (e.g. Brady, Konkle, Gill, Oliva, & Alvarez, 2013). That is, recall is the result of either remembering (with some noise) or guessing. This stands in contrast to Bayesian models of cognition while assume that prior knowledge about the world influences judgments, and that recall is a combination of expectations learned from the environment and noisy memory representations. Here, we evaluate the time course of fidelity in LT episodic memory, and the relative contribution of prior category knowledge and guessing, using a continuous recall paradigm. At an aggregate level, performance reflects a high rate of guessing. However, when aggregate data is partitioned by lag (i.e., the number of presentations from study to test), or is un-aggregated, performance appears to be more complex than just remembering with some noise and guessing. We implemented three models: the standard remember-guess model, a three-component remember-guess model, and a Bayesian mixture model and evaluated these models against the data. The results emphasize the importance of taking into account the influence of prior category knowledge on memory. Copyright © 2016 Elsevier Inc. All rights reserved.

Reef Sharks Exhibit Site-Fidelity and Higher Relative Abundance in Marine Reserves on the Mesoamerican Barrier Reef

PubMed Central

Bond, Mark E.; Babcock, Elizabeth A.; Pikitch, Ellen K.; Abercrombie, Debra L.; Lamb, Norlan F.; Chapman, Demian D.

2012-01-01

Carcharhinid sharks can make up a large fraction of the top predators inhabiting tropical marine ecosystems and have declined in many regions due to intense fishing pressure. There is some support for the hypothesis that carcharhinid species that complete their life-cycle within coral reef ecosystems, hereafter referred to as “reef sharks”, are more abundant inside no-take marine reserves due to a reduction in fishing pressure (i.e., they benefit from marine reserves). Key predictions of this hypothesis are that (a) individual reef sharks exhibit high site-fidelity to these protected areas and (b) their relative abundance will generally be higher in these areas compared to fished reefs. To test this hypothesis for the first time in Caribbean coral reef ecosystems we combined acoustic monitoring and baited remote underwater video (BRUV) surveys to measure reef shark site-fidelity and relative abundance, respectively. We focused on the Caribbean reef shark (Carcharhinus perezi), the most common reef shark in the Western Atlantic, at Glover's Reef Marine Reserve (GRMR), Belize. Acoustically tagged sharks (N = 34) were detected throughout the year at this location and exhibited strong site-fidelity. Shark presence or absence on 200 BRUVs deployed at GRMR and three other sites (another reserve site and two fished reefs) showed that the factor “marine reserve” had a significant positive effect on reef shark presence. We rejected environmental factors or site-environment interactions as predominant drivers of this pattern. These results are consistent with the hypothesis that marine reserves can benefit reef shark populations and we suggest new hypotheses to determine the underlying mechanism(s) involved: reduced fishing mortality or enhanced prey availability. PMID:22412965

High Fidelity Simulation Experience in Emergency settings: doctors and nurses satisfaction levels.

PubMed

Calamassi, Diletta; Nannelli, Tiziana; Guazzini, Andrea; Rasero, Laura; Bambi, Stefano

2016-11-22

Lots of studies describe High Fidelity Simulation (HFS) as an experience well-accepted by the learners. This study has explored doctors and nurses satisfaction levels during HFS sessions, searching the associations with the setting of simulation events (simulation center or on the field simulation). Moreover, we studied the correlation between HFS experience satisfaction levels and the socio-demographic features of the participants. Mixed method study, using the Satisfaction of High-Fidelity Simulation Experience (SESAF) questionnaire through an online survey. SESAF was administered to doctors and nurses who previously took part to HFS sessions in a simulation center or in the field. Quantitative data were analyzed through descriptive and inferential statistics methods; qualitative data was performed through the Giorgi method. 143 doctors and 94 nurses filled the questionnaire. The satisfaction level was high: on a 10 points scale, the mean score was 8.17 (SD±1.924). There was no significant difference between doctors and nurses satisfaction levels in almost all the SESAF factors. We didn't find any correlation between gender and HFS experience satisfaction levels. The knowledge of theoretical aspects of the simulated case before the HFS experience is related to a higher general satisfaction (r=0.166 p=0.05), a higher effectiveness of debriefing (r=0,143 p=0,05), and a higher professional impact (r=0.143 p=0.05). The respondents that performed a HFS on the field, were more satisfied than the others, and experienced a higher "professional impact", "clinical reasoning and self efficacy", and "team dynamics" (p< 0,01). Narrative data suggest that HFS facilitators should improve their behaviors during the debriefing. Healthcare managers should extend the HFS to all kind of healthcare workers in real clinical settings. There is the need to improve and implement the communication competences of HFS facilitators.

Finite-size effects in Anderson localization of one-dimensional Bose-Einstein condensates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cestari, J. C. C.; Foerster, A.; Gusmao, M. A.

We investigate the disorder-induced localization transition in Bose-Einstein condensates for the Anderson and Aubry-Andre models in the noninteracting limit using exact diagonalization. We show that, in addition to the standard superfluid fraction, other tools such as the entanglement and fidelity can provide clear signatures of the transition. Interestingly, the fidelity exhibits good sensitivity even for small lattices. Effects of the system size on these quantities are analyzed in detail, including the determination of a finite-size-scaling law for the critical disorder strength in the case of the Anderson model.

The Kepler End-to-End Model: Creating High-Fidelity Simulations to Test Kepler Ground Processing

NASA Technical Reports Server (NTRS)

Bryson, Stephen T.; Jenkins, Jon M.; Peters, Dan J.; Tenenbaum, Peter P.; Klaus, Todd C.; Gunter, Jay P.; Cote, Miles T.; Caldwell, Douglas A.

2010-01-01

The Kepler mission is designed to detect the transit of Earth-like planets around Sun-like stars by observing 100,000 stellar targets. Developing and testing the Kepler ground-segment processing system, in particular the data analysis pipeline, requires high-fidelity simulated data. This simulated data is provided by the Kepler End-to-End Model (ETEM). ETEM simulates the astrophysics of planetary transits and other phenomena, properties of the Kepler spacecraft and the format of the downlinked data. Major challenges addressed by ETEM include the rapid production of large amounts of simulated data, extensibility and maintainability.

Flexible aircraft dynamic modeling for dynamic analysis and control synthesis

NASA Technical Reports Server (NTRS)

Schmidt, David K.

1989-01-01

The linearization and simplification of a nonlinear, literal model for flexible aircraft is highlighted. Areas of model fidelity that are critical if the model is to be used for control system synthesis are developed and several simplification techniques that can deliver the necessary model fidelity are discussed. These techniques include both numerical and analytical approaches. An analytical approach, based on first-order sensitivity theory is shown to lead not only to excellent numerical results, but also to closed-form analytical expressions for key system dynamic properties such as the pole/zero factors of the vehicle transfer-function matrix. The analytical results are expressed in terms of vehicle mass properties, vibrational characteristics, and rigid-body and aeroelastic stability derivatives, thus leading to the underlying causes for critical dynamic characteristics.

High fidelity simulation based team training in urology: a preliminary interdisciplinary study of technical and nontechnical skills in laparoscopic complications management.

PubMed

Lee, Jason Y; Mucksavage, Phillip; Canales, Cecilia; McDougall, Elspeth M; Lin, Sharon

2012-04-01

Simulation based team training provides an opportunity to develop interdisciplinary communication skills and address potential medical errors in a high fidelity, low stakes environment. We evaluated the implementation of a novel simulation based team training scenario and assessed the technical and nontechnical performance of urology and anesthesiology residents. Urology residents were randomly paired with anesthesiology residents to participate in a simulation based team training scenario involving the management of 2 scripted critical events during laparoscopic radical nephrectomy, including the vasovagal response to pneumoperitoneum and renal vein injury during hilar dissection. A novel kidney surgical model and a high fidelity mannequin simulator were used for the simulation. A debriefing session followed each simulation based team training scenario. Assessments of technical and nontechnical performance were made using task specific checklists and global rating scales. A total of 16 residents participated, of whom 94% rated the simulation based team training scenario as useful for communication skill training. Also, 88% of urology residents believed that the kidney surgical model was useful for technical skill training. Urology resident training level correlated with technical performance (p=0.004) and blood loss during renal vein injury management (p=0.022) but not with nontechnical performance. Anesthesia resident training level correlated with nontechnical performance (p=0.036). Urology residents consistently rated themselves higher on nontechnical performance than did faculty (p=0.033). Anesthesia residents did not differ in the self-assessment of nontechnical performance compared to faculty assessments. Residents rated the simulation based team training scenario as useful for interdisciplinary communication skill training. Urology resident training level correlated with technical performance but not with nontechnical performance. Urology residents consistently overestimated their nontechnical performance. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Coordinating DNA polymerase traffic during high and low fidelity synthesis.

PubMed

Sutton, Mark D

2010-05-01

With the discovery that organisms possess multiple DNA polymerases (Pols) displaying different fidelities, processivities, and activities came the realization that mechanisms must exist to manage the actions of these diverse enzymes to prevent gratuitous mutations. Although many of the Pols encoded by most organisms are largely accurate, and participate in DNA replication and DNA repair, a sizeable fraction display a reduced fidelity, and act to catalyze potentially error-prone translesion DNA synthesis (TLS) past lesions that persist in the DNA. Striking the proper balance between use of these different enzymes during DNA replication, DNA repair, and TLS is essential for ensuring accurate duplication of the cell's genome. This review highlights mechanisms that organisms utilize to manage the actions of their different Pols. A particular emphasis is placed on discussion of current models for how different Pols switch places with each other at the replication fork during high fidelity replication and potentially error-pone TLS. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Illustrating the multiple facets and levels of fidelity of implementation to a teacher classroom management intervention.

PubMed

Reinke, Wendy M; Herman, Keith C; Stormont, Melissa; Newcomer, Lori; David, Kimberly

2013-11-01

Many school-based interventions to promote student mental health rely on teachers as implementers. Thus, understanding the interplay between the multiple domains of fidelity to the intervention and intervention support systems such as coaching and teacher implementation of new skills is an important aspect of implementation science. This study describes a systematic process for assessing multiple domains of fidelity. Data from a larger efficacy trial of the Incredible Years Teacher Classroom Management (IY TCM) program are utilized. Data on fidelity to the IY TCM workshop training sessions and onsite weekly coaching indicate that workshop leaders and the IY TCM coach implemented the training and coaching model with adequate adherence. Further, workshop leaders' ratings of engagement were associated with teacher implementation of specific praise, following training on this content. Lastly, the IY TCM coach differentiation of teacher exposure to coaching was evaluated and found to be associated with teacher implementation of classroom management practices and student disruptive behavior.

Automating Initial Guess Generation for High Fidelity Trajectory Optimization Tools

NASA Technical Reports Server (NTRS)

Villa, Benjamin; Lantoine, Gregory; Sims, Jon; Whiffen, Gregory

2013-01-01

Many academic studies in spaceflight dynamics rely on simplified dynamical models, such as restricted three-body models or averaged forms of the equations of motion of an orbiter. In practice, the end result of these preliminary orbit studies needs to be transformed into more realistic models, in particular to generate good initial guesses for high-fidelity trajectory optimization tools like Mystic. This paper reviews and extends some of the approaches used in the literature to perform such a task, and explores the inherent trade-offs of such a transformation with a view toward automating it for the case of ballistic arcs. Sample test cases in the libration point regimes and small body orbiter transfers are presented.

Predictors of outcomes of assertive outreach teams: a 3-year follow-up study in North East England.

PubMed

Carpenter, John; Luce, Anna; Wooff, David

2011-06-01

Assertive outreach (AO) is a required component of services for people with severe mental illness in England. However, the claims to its effectiveness have been contested and the relationships between team organisation, including model fidelity, the use of mental health interventions and outcomes for service users remain unclear. Three-year follow up of 33 AO teams was conducted using standardised measures of model fidelity and mental health interventions, and of current location and a range of outcomes for service users (n = 628). Predictors of the number of hospital admissions, mental health and social functioning at T2, and discharge from the team as 'improved' were modelled using multivariate regression analyses. Teams had moderate mean ratings of fidelity to the AO model. All rated highly on the core intervention modalities of engagement, assessment and care co-ordination, but ratings for psychosocial interventions were comparatively low. Two-thirds (462) of service users were still in AO and data were returned on 400 (87%). There was evidence of small improvements in mental health and social functioning and a reduction in the mean number of hospital admissions in the previous 2 years (from 2.09 to 1.39). Poor outcomes were predicted variously by service users' characteristics, previous psychiatric history, poor collaboration with services, homelessness and dual diagnosis. Fidelity to the AO model did not emerge as a predictor of outcome, but the team working for extended hours was associated with more frequent in-patient admissions and less likelihood of discharge from AO. Supportive interventions in daily living, together with the team's use of family and psychological interventions were also associated with poorer outcomes. Possible explanations for these unexpected findings are considered. AO appears to have been quite successful in keeping users engaged over a substantial period and to have an impact in supporting many people to live in the community and to avoid the necessity of psychiatric hospital admission. However, teams should focus on those with a history of hospital admissions, who do not engage well with services and for whom outcomes are less good. Psychosocial interventions should be applied. The relationship between model fidelity, team organisation, mental health interventions and outcomes is not straightforward and deserves further study.

A Transfer of Training Study of Control Loader Dynamics

NASA Technical Reports Server (NTRS)

Cardullo, Frank M.; Stanco, Anthony A.; Kelly, Lon C.; Houck, Jacob A.; Grube, Richard C.

2011-01-01

The control inceptor used in a simulated vehicle is an important part in maintaining the fidelity of a simulation. The force feedback provided by the control inceptor gives the operator important cues to maintain adequate performance. The dynamics of a control inceptor are typically based on a second order spring mass damper system with damping, force gradient, breakout force, and natural frequency parameters. Changing these parameters can have a great effect on pilot or driver control of the vehicle. The neuromuscular system has a very important role in manipulating the control inceptor within a vehicle. Many studies by McRuer, Aponso, and Hess have dealt with modeling the neuromuscular system and quantifying the effects of a high fidelity control loader as compared to a low fidelity control loader. Humans are adaptive in nature and their control behavior changes based on different control loader dynamics. Humans will change their control behavior to maintain tracking bandwidth and minimize tracking error. This paper reports on a quasi-transfer of training experiment which was performed at the NASA Langley Research Center. The quasi transfer of training study used a high fidelity control loader and a low fidelity control loader. Subjects trained in both simulations and then were transferred to the high fidelity control loader simulation. The parameters for the high fidelity control loader were determined from the literature. The low fidelity control loader parameters were found through testing of a simple computer joystick. A disturbance compensatory task is employed. The compensatory task involves implementing a simple horizon out the window display. A disturbance consisting of a sum of sines is used. The task consists of the subject compensating for the disturbance on the roll angle of the aircraft. The vehicle dynamics are represented as 1/s and 1/s2. The subject will try to maintain level flight throughout the experiment. The subjects consist of non-pilots to remove any effects of pilot experience. First, this paper discusses the implementation of the disturbance compensation task. Second, the high and low fidelity parameters used within the experiment are presented. Finally, an explanation of results from the experiments is presented.

Contributions of the stochastic shape wake model to predictions of aerodynamic loads and power under single wake conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doubrawa, P.; Barthelmie, R. J.; Wang, H.

The contribution of wake meandering and shape asymmetry to load and power estimates is quantified by comparing aeroelastic simulations initialized with different inflow conditions: an axisymmetric base wake, an unsteady stochastic shape wake, and a large-eddy simulation with rotating actuator-line turbine representation. Time series of blade-root and tower base bending moments are analyzed. We find that meandering has a large contribution to the fluctuation of the loads. Moreover, considering the wake edge intermittence via the stochastic shape model improves the simulation of load and power fluctuations and of the fatigue damage equivalent loads. Furthermore, these results indicate that the stochasticmore » shape wake simulator is a valuable addition to simplified wake models when seeking to obtain higher-fidelity computationally inexpensive predictions of loads and power.« less

Hybrid transport and diffusion modeling using electron thermal transport Monte Carlo SNB in DRACO

NASA Astrophysics Data System (ADS)

Chenhall, Jeffrey; Moses, Gregory

2017-10-01

The iSNB (implicit Schurtz Nicolai Busquet) multigroup diffusion electron thermal transport method is adapted into an Electron Thermal Transport Monte Carlo (ETTMC) transport method to better model angular and long mean free path non-local effects. Previously, the ETTMC model had been implemented in the 2D DRACO multiphysics code and found to produce consistent results with the iSNB method. Current work is focused on a hybridization of the computationally slower but higher fidelity ETTMC transport method with the computationally faster iSNB diffusion method in order to maximize computational efficiency. Furthermore, effects on the energy distribution of the heat flux divergence are studied. Work to date on the hybrid method will be presented. This work was supported by Sandia National Laboratories and the Univ. of Rochester Laboratory for Laser Energetics.

Contributions of the stochastic shape wake model to predictions of aerodynamic loads and power under single wake conditions

DOE PAGES

Doubrawa, P.; Barthelmie, R. J.; Wang, H.; ...

2016-10-03

The contribution of wake meandering and shape asymmetry to load and power estimates is quantified by comparing aeroelastic simulations initialized with different inflow conditions: an axisymmetric base wake, an unsteady stochastic shape wake, and a large-eddy simulation with rotating actuator-line turbine representation. Time series of blade-root and tower base bending moments are analyzed. We find that meandering has a large contribution to the fluctuation of the loads. Moreover, considering the wake edge intermittence via the stochastic shape model improves the simulation of load and power fluctuations and of the fatigue damage equivalent loads. Furthermore, these results indicate that the stochasticmore » shape wake simulator is a valuable addition to simplified wake models when seeking to obtain higher-fidelity computationally inexpensive predictions of loads and power.« less

Comments on papers by Reichert and Wong. [information theory for molecular taxonomy

NASA Technical Reports Server (NTRS)

Gatlin, L. L.

1974-01-01

Papers of Reichert and Wong (1971) and Reichert (1972) are referred to as erroneous in stating that in their work with cytochrome c sequences they demonstrated that vertebrates have achieved a higher organized genetic message with a higher fidelity in the DNA-to-protein information processing channel. Arguments are given to contest that statement.

Local-Scale Simulations of Nucleate Boiling on Micrometer Featured Surfaces: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sitaraman, Hariswaran; Moreno, Gilberto; Narumanchi, Sreekant V

2017-08-03

A high-fidelity computational fluid dynamics (CFD)-based model for bubble nucleation of the refrigerant HFE7100 on micrometer-featured surfaces is presented in this work. The single-fluid incompressible Navier-Stokes equations, along with energy transport and natural convection effects are solved on a featured surface resolved grid. An a priori cavity detection method is employed to convert raw profilometer data of a surface into well-defined cavities. The cavity information and surface morphology are represented in the CFD model by geometric mesh deformations. Surface morphology is observed to initiate buoyancy-driven convection in the liquid phase, which in turn results in faster nucleation of cavities. Simulationsmore » pertaining to a generic rough surface show a trend where smaller size cavities nucleate with higher wall superheat. This local-scale model will serve as a self-consistent connection to larger device scale continuum models where local feature representation is not possible.« less

Local-Scale Simulations of Nucleate Boiling on Micrometer-Featured Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sitaraman, Hariswaran; Moreno, Gilberto; Narumanchi, Sreekant V

2017-07-12

A high-fidelity computational fluid dynamics (CFD)-based model for bubble nucleation of the refrigerant HFE7100 on micrometer-featured surfaces is presented in this work. The single-fluid incompressible Navier-Stokes equations, along with energy transport and natural convection effects are solved on a featured surface resolved grid. An a priori cavity detection method is employed to convert raw profilometer data of a surface into well-defined cavities. The cavity information and surface morphology are represented in the CFD model by geometric mesh deformations. Surface morphology is observed to initiate buoyancy-driven convection in the liquid phase, which in turn results in faster nucleation of cavities. Simulationsmore » pertaining to a generic rough surface show a trend where smaller size cavities nucleate with higher wall superheat. This local-scale model will serve as a self-consistent connection to larger device scale continuum models where local feature representation is not possible.« less

Revisiting low-fidelity two-fluid models for gas-solids transport

NASA Astrophysics Data System (ADS)

Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

2016-08-01

Two-phase gas-solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas-solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe-Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

Inadequacy representation of flamelet-based RANS model for turbulent non-premixed flame

NASA Astrophysics Data System (ADS)

Lee, Myoungkyu; Oliver, Todd; Moser, Robert

2017-11-01

Stochastic representations for model inadequacy in RANS-based models of non-premixed jet flames are developed and explored. Flamelet-based RANS models are attractive for engineering applications relative to higher-fidelity methods because of their low computational costs. However, the various assumptions inherent in such models introduce errors that can significantly affect the accuracy of computed quantities of interest. In this work, we develop an approach to represent the model inadequacy of the flamelet-based RANS model. In particular, we pose a physics-based, stochastic PDE for the triple correlation of the mixture fraction. This additional uncertain state variable is then used to construct perturbations of the PDF for the instantaneous mixture fraction, which is used to obtain an uncertain perturbation of the flame temperature. A hydrogen-air non-premixed jet flame is used to demonstrate the representation of the inadequacy of the flamelet-based RANS model. This work was supported by DARPA-EQUiPS(Enabling Quantification of Uncertainty in Physical Systems) program.

Participatory ergonomics simulation of hospital work systems: The influence of simulation media on simulation outcome.

PubMed

Andersen, Simone Nyholm; Broberg, Ole

2015-11-01

Current application of work system simulation in participatory ergonomics (PE) design includes a variety of different simulation media. However, the actual influence of the media attributes on the simulation outcome has received less attention. This study investigates two simulation media: full-scale mock-ups and table-top models. The aim is to compare, how the media attributes of fidelity and affordance influence the ergonomics identification and evaluation in PE design of hospital work systems. The results illustrate, how the full-scale mock-ups' high fidelity of room layout and affordance of tool operation support ergonomics identification and evaluation related to the work system entities space and technologies & tools. The table-top models' high fidelity of function relations and affordance of a helicopter view support ergonomics identification and evaluation related to the entity organization. Furthermore, the study addresses the form of the identified and evaluated conditions, being either identified challenges or tangible design criteria. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Strategies to balance fidelity to Housing First principles with local realities: lessons from a large urban centre.

PubMed

O'Campo, Patricia; Zerger, Suzanne; Gozdzik, Agnes; Jeyaratnam, Jeyagobi; Stergiopoulos, Vicky

2015-05-01

The importance of program implementation in achieving desired outcomes is well-documented, but there remains a need for concrete guidance on how to achieve fidelity to evidence-based models within dynamic local contexts. Housing First (HF), an evidence-based model for people experiencing homelessness and mental illness, provides an important test-case for such guidance; it targets a uniquely underserved subpopulation with complex needs, and is delivered by practitioners with varying knowledge and skill levels. Scientific evidence affirms HF's effectiveness, but its rapid dissemination has outpaced the ability to monitor not only whether it is being implemented with fidelity, but also how this can be achieved within variable local contexts and challenges. This qualitative study contributes to this need by capturing insights from practitioners on implementation challenges and specific strategies developed to overcome them. Findings reinforce the importance of developing HF-specific implementation guidelines, and of engaging relevant stakeholders throughout all phases of that development.

Regression-based reduced-order models to predict transient thermal output for enhanced geothermal systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mudunuru, Maruti Kumar; Karra, Satish; Harp, Dylan Robert

Reduced-order modeling is a promising approach, as many phenomena can be described by a few parameters/mechanisms. An advantage and attractive aspect of a reduced-order model is that it is computational inexpensive to evaluate when compared to running a high-fidelity numerical simulation. A reduced-order model takes couple of seconds to run on a laptop while a high-fidelity simulation may take couple of hours to run on a high-performance computing cluster. The goal of this paper is to assess the utility of regression-based reduced-order models (ROMs) developed from high-fidelity numerical simulations for predicting transient thermal power output for an enhanced geothermal reservoirmore » while explicitly accounting for uncertainties in the subsurface system and site-specific details. Numerical simulations are performed based on equally spaced values in the specified range of model parameters. Key sensitive parameters are then identified from these simulations, which are fracture zone permeability, well/skin factor, bottom hole pressure, and injection flow rate. We found the fracture zone permeability to be the most sensitive parameter. The fracture zone permeability along with time, are used to build regression-based ROMs for the thermal power output. The ROMs are trained and validated using detailed physics-based numerical simulations. Finally, predictions from the ROMs are then compared with field data. We propose three different ROMs with different levels of model parsimony, each describing key and essential features of the power production curves. The coefficients in the proposed regression-based ROMs are developed by minimizing a non-linear least-squares misfit function using the Levenberg–Marquardt algorithm. The misfit function is based on the difference between numerical simulation data and reduced-order model. ROM-1 is constructed based on polynomials up to fourth order. ROM-1 is able to accurately reproduce the power output of numerical simulations for low values of permeabilities and certain features of the field-scale data. ROM-2 is a model with more analytical functions consisting of polynomials up to order eight, exponential functions and smooth approximations of Heaviside functions, and accurately describes the field-data. At higher permeabilities, ROM-2 reproduces numerical results better than ROM-1, however, there is a considerable deviation from numerical results at low fracture zone permeabilities. ROM-3 consists of polynomials up to order ten, and is developed by taking the best aspects of ROM-1 and ROM-2. ROM-1 is relatively parsimonious than ROM-2 and ROM-3, while ROM-2 overfits the data. ROM-3 on the other hand, provides a middle ground for model parsimony. Based on R 2-values for training, validation, and prediction data sets we found that ROM-3 is better model than ROM-2 and ROM-1. For predicting thermal drawdown in EGS applications, where high fracture zone permeabilities (typically greater than 10 –15 m 2) are desired, ROM-2 and ROM-3 outperform ROM-1. As per computational time, all the ROMs are 10 4 times faster when compared to running a high-fidelity numerical simulation. In conclusion, this makes the proposed regression-based ROMs attractive for real-time EGS applications because they are fast and provide reasonably good predictions for thermal power output.« less

Regression-based reduced-order models to predict transient thermal output for enhanced geothermal systems

DOE PAGES

Mudunuru, Maruti Kumar; Karra, Satish; Harp, Dylan Robert; ...

2017-07-10

Reduced-order modeling is a promising approach, as many phenomena can be described by a few parameters/mechanisms. An advantage and attractive aspect of a reduced-order model is that it is computational inexpensive to evaluate when compared to running a high-fidelity numerical simulation. A reduced-order model takes couple of seconds to run on a laptop while a high-fidelity simulation may take couple of hours to run on a high-performance computing cluster. The goal of this paper is to assess the utility of regression-based reduced-order models (ROMs) developed from high-fidelity numerical simulations for predicting transient thermal power output for an enhanced geothermal reservoirmore » while explicitly accounting for uncertainties in the subsurface system and site-specific details. Numerical simulations are performed based on equally spaced values in the specified range of model parameters. Key sensitive parameters are then identified from these simulations, which are fracture zone permeability, well/skin factor, bottom hole pressure, and injection flow rate. We found the fracture zone permeability to be the most sensitive parameter. The fracture zone permeability along with time, are used to build regression-based ROMs for the thermal power output. The ROMs are trained and validated using detailed physics-based numerical simulations. Finally, predictions from the ROMs are then compared with field data. We propose three different ROMs with different levels of model parsimony, each describing key and essential features of the power production curves. The coefficients in the proposed regression-based ROMs are developed by minimizing a non-linear least-squares misfit function using the Levenberg–Marquardt algorithm. The misfit function is based on the difference between numerical simulation data and reduced-order model. ROM-1 is constructed based on polynomials up to fourth order. ROM-1 is able to accurately reproduce the power output of numerical simulations for low values of permeabilities and certain features of the field-scale data. ROM-2 is a model with more analytical functions consisting of polynomials up to order eight, exponential functions and smooth approximations of Heaviside functions, and accurately describes the field-data. At higher permeabilities, ROM-2 reproduces numerical results better than ROM-1, however, there is a considerable deviation from numerical results at low fracture zone permeabilities. ROM-3 consists of polynomials up to order ten, and is developed by taking the best aspects of ROM-1 and ROM-2. ROM-1 is relatively parsimonious than ROM-2 and ROM-3, while ROM-2 overfits the data. ROM-3 on the other hand, provides a middle ground for model parsimony. Based on R 2-values for training, validation, and prediction data sets we found that ROM-3 is better model than ROM-2 and ROM-1. For predicting thermal drawdown in EGS applications, where high fracture zone permeabilities (typically greater than 10 –15 m 2) are desired, ROM-2 and ROM-3 outperform ROM-1. As per computational time, all the ROMs are 10 4 times faster when compared to running a high-fidelity numerical simulation. In conclusion, this makes the proposed regression-based ROMs attractive for real-time EGS applications because they are fast and provide reasonably good predictions for thermal power output.« less

Regularized maximum pure-state input-output fidelity of a quantum channel

NASA Astrophysics Data System (ADS)

Ernst, Moritz F.; Klesse, Rochus

2017-12-01

As a toy model for the capacity problem in quantum information theory we investigate finite and asymptotic regularizations of the maximum pure-state input-output fidelity F (N ) of a general quantum channel N . We show that the asymptotic regularization F ˜(N ) is lower bounded by the maximum output ∞ -norm ν∞(N ) of the channel. For N being a Pauli channel, we find that both quantities are equal.

Modeling Fault Diagnosis Performance on a Marine Powerplant Simulator.

DTIC Science & Technology

1985-08-01

two definitions are very similar. They emphasize that fidelity is a two dimensional -:oncept. They also pointed out the measurement prob- lems. Tasks...simulator duplicares cne enscr-: ztimulation, 4. . rnamic motion cues , visual :ues, ec. ?svcno ogicai fidelity is simply the degree to which the trainee...functions is only acceptable if the performance is paced by tne system, i.e., cues from the system serve to initiate elementary, skilled sub-routines

Imperfect construction of microclusters

NASA Astrophysics Data System (ADS)

Schneider, E.; Zhou, K.; Gilbert, G.; Weinstein, Y. S.

2014-01-01

Microclusters are the basic building blocks used to construct cluster states capable of supporting fault-tolerant quantum computation. In this paper, we explore the consequences of errors on microcluster construction using two error models. To quantify the effect of the errors we calculate the fidelity of the constructed microclusters and the fidelity with which two such microclusters can be fused together. Such simulations are vital for gauging the capability of an experimental system to achieve fault tolerance.

Advanced Computational Methods for Thermal Radiative Heat Transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tencer, John; Carlberg, Kevin Thomas; Larsen, Marvin E.

2016-10-01

Participating media radiation (PMR) in weapon safety calculations for abnormal thermal environments are too costly to do routinely. This cost may be s ubstantially reduced by applying reduced order modeling (ROM) techniques. The application of ROM to PMR is a new and unique approach for this class of problems. This approach was investigated by the authors and shown to provide significant reductions in the computational expense associated with typical PMR simulations. Once this technology is migrated into production heat transfer analysis codes this capability will enable the routine use of PMR heat transfer in higher - fidelity simulations of weaponmore » resp onse in fire environments.« less

Overview of the Development for a Suite of Low-Thrust Trajectory Analysis Tools

NASA Technical Reports Server (NTRS)

Kos, Larry D.; Polsgrove, Tara; Hopkins, Randall; Thomas, Dan; Sims, Jon A.

2006-01-01

A NASA intercenter team has developed a suite of low-thrust trajectory analysis tools to make a significant improvement in three major facets of low-thrust trajectory and mission analysis. These are: 1) ease of use, 2) ability to more robustly converge to solutions, and 3) higher fidelity modeling and accuracy of results. Due mostly to the short duration of the development, the team concluded that a suite of tools was preferred over having one integrated tool. This tool-suite, their characteristics, and their applicability will be described. Trajectory analysts can read this paper and determine which tool is most appropriate for their problem.

Quiet geomagnetic field representation for all days and latitudes

USGS Publications Warehouse

Campbell, W.H.; Schiffmacher, E.R.; Arora, B.R.

1992-01-01

Describes a technique for obtaining the quiet-time geomagnetic field variation expected for all days of the year and distribution of latitudes from a limited set of selected quiet days within a year at a discrete set of locations. A data set of observatories near 75??E longitude was used as illustration. The method relies upon spatial smoothing of the decomposed spectral components. An evaluation of the fidelity of the resulting model shows correlation coefficients usually above 0.9 at the lower latitudes and near 0.7 at the higher latitudes with variations identified as dependent upon season and field element. -from Authors

State-transfer simulation in integrated waveguide circuits

NASA Astrophysics Data System (ADS)

Latmiral, L.; Di Franco, C.; Mennea, P. L.; Kim, M. S.

2015-08-01

Spin-chain models have been widely studied in terms of quantum information processes, for instance for the faithful transmission of quantum states. Here, we investigate the limitations of mapping this process to an equivalent one through a bosonic chain. In particular, we keep in mind experimental implementations, which the progress in integrated waveguide circuits could make possible in the very near future. We consider the feasibility of exploiting the higher dimensionality of the Hilbert space of the chain elements for the transmission of a larger amount of information, and the effects of unwanted excitations during the process. Finally, we exploit the information-flux method to provide bounds to the transfer fidelity.

Realistic and affordable lo-fidelity model for learning bronchoscopic transbronchial needle aspiration.

PubMed

Goldberg, Robert; Colt, Henri G; Davoudi, Mohsen; Cherrison, Larry

2009-09-01

Transbronchial needle aspiration (TBNA) is used to sample mediastinal abnormalities and lymph node stations for diagnostic purposes and lung cancer staging. The procedure is underused, operator dependent, and reputed to have a steep learning curve. Other difficulties arise from a bronchoscopist's failure to insert the needle satisfactorily into the target node. The purpose of this study was to evaluate the realism and helpfulness of a lo-fidelity, easily constructed hybrid model used for learning and practicing TBNA. The model is constructed by attaching a porcine tracheobronchial tree to a Laerdal Airway Model mounted on polyvinyl chloride (PVC) piping. Twelve individuals with various levels of bronchoscopy training and experience were given a 15-min introductory PowerPoint presentation on TBNA strategy and planning, execution, and response to complications. Participants then practiced TBNA alone and with guidance, aided by an assistant, as many times as individually necessary to feel comfortable with the procedure. A five-point Likert scale 8-item questionnaire was then completed. Participants were unanimously positive about their experience (mean scores 4.25-4.91). The model was realistic, provided increased comfort with TBNA techniques, and allowed practice of communication skills. This realistic, affordable, and easily constructed hybrid lo-fidelity airway model allows beginner and experienced bronchoscopists opportunities to learn and practice basic TBNA techniques and team communication skills without placing patients at risk.

Resolution dependence of precipitation statistical fidelity in hindcast simulations

DOE PAGES

O'Brien, Travis A.; Collins, William D.; Kashinath, Karthik; ...

2016-06-19

This article is a U.S. Government work and is in the public domain in the USA. Numerous studies have shown that atmospheric models with high horizontal resolution better represent the physics and statistics of precipitation in climate models. While it is abundantly clear from these studies that high-resolution increases the rate of extreme precipitation, it is not clear whether these added extreme events are “realistic”; whether they occur in simulations in response to the same forcings that drive similar events in reality. In order to understand whether increasing horizontal resolution results in improved model fidelity, a hindcast-based, multiresolution experimental designmore » has been conceived and implemented: the InitiaLIzed-ensemble, Analyze, and Develop (ILIAD) framework. The ILIAD framework allows direct comparison between observed and simulated weather events across multiple resolutions and assessment of the degree to which increased resolution improves the fidelity of extremes. Analysis of 5 years of daily 5 day hindcasts with the Community Earth System Model at horizontal resolutions of 220, 110, and 28 km shows that: (1) these hindcasts reproduce the resolution-dependent increase of extreme precipitation that has been identified in longer-duration simulations, (2) the correspondence between simulated and observed extreme precipitation improves as resolution increases; and (3) this increase in extremes and precipitation fidelity comes entirely from resolved-scale precipitation. Evidence is presented that this resolution-dependent increase in precipitation intensity can be explained by the theory of Rauscher et al. (), which states that precipitation intensifies at high resolution due to an interaction between the emergent scaling (spectral) properties of the wind field and the constraint of fluid continuity.« less

Resolution dependence of precipitation statistical fidelity in hindcast simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, Travis A.; Collins, William D.; Kashinath, Karthik

This article is a U.S. Government work and is in the public domain in the USA. Numerous studies have shown that atmospheric models with high horizontal resolution better represent the physics and statistics of precipitation in climate models. While it is abundantly clear from these studies that high-resolution increases the rate of extreme precipitation, it is not clear whether these added extreme events are “realistic”; whether they occur in simulations in response to the same forcings that drive similar events in reality. In order to understand whether increasing horizontal resolution results in improved model fidelity, a hindcast-based, multiresolution experimental designmore » has been conceived and implemented: the InitiaLIzed-ensemble, Analyze, and Develop (ILIAD) framework. The ILIAD framework allows direct comparison between observed and simulated weather events across multiple resolutions and assessment of the degree to which increased resolution improves the fidelity of extremes. Analysis of 5 years of daily 5 day hindcasts with the Community Earth System Model at horizontal resolutions of 220, 110, and 28 km shows that: (1) these hindcasts reproduce the resolution-dependent increase of extreme precipitation that has been identified in longer-duration simulations, (2) the correspondence between simulated and observed extreme precipitation improves as resolution increases; and (3) this increase in extremes and precipitation fidelity comes entirely from resolved-scale precipitation. Evidence is presented that this resolution-dependent increase in precipitation intensity can be explained by the theory of Rauscher et al. (), which states that precipitation intensifies at high resolution due to an interaction between the emergent scaling (spectral) properties of the wind field and the constraint of fluid continuity.« less

HIGH-FIDELITY SIMULATION-DRIVEN MODEL DEVELOPMENT FOR COARSE-GRAINED COMPUTATIONAL FLUID DYNAMICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanna, Botros N.; Dinh, Nam T.; Bolotnov, Igor A.

Nuclear reactor safety analysis requires identifying various credible accident scenarios and determining their consequences. For a full-scale nuclear power plant system behavior, it is impossible to obtain sufficient experimental data for a broad range of risk-significant accident scenarios. In single-phase flow convective problems, Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) can provide us with high fidelity results when physical data are unavailable. However, these methods are computationally expensive and cannot be afforded for simulation of long transient scenarios in nuclear accidents despite extraordinary advances in high performance scientific computing over the past decades. The major issue is themore » inability to make the transient computation parallel, thus making number of time steps required in high-fidelity methods unaffordable for long transients. In this work, we propose to apply a high fidelity simulation-driven approach to model sub-grid scale (SGS) effect in Coarse Grained Computational Fluid Dynamics CG-CFD. This approach aims to develop a statistical surrogate model instead of the deterministic SGS model. We chose to start with a turbulent natural convection case with volumetric heating in a horizontal fluid layer with a rigid, insulated lower boundary and isothermal (cold) upper boundary. This scenario of unstable stratification is relevant to turbulent natural convection in a molten corium pool during a severe nuclear reactor accident, as well as in containment mixing and passive cooling. The presented approach demonstrates how to create a correction for the CG-CFD solution by modifying the energy balance equation. A global correction for the temperature equation proves to achieve a significant improvement to the prediction of steady state temperature distribution through the fluid layer.« less

Development and Implementation: B’More Healthy Communities for Kid’s Store and Wholesaler Intervention

PubMed Central

Schwendler, Teresa; Shipley, Cara; Budd, Nadine; Trude, Angela; Surkan, Pamela J.; Steeves, Elizabeth Anderson; de Morais Sato, Priscila; Eckmann, Thomas; Loh, Hong; Gittelsohn, Joel

2017-01-01

Higher rates of obesity and obesity-related chronic disease are prevalent in communities where there is limited access to affordable, healthy food. The B’More Healthy Communities for Kids (BHCK) trial worked at multiple levels of the food environment including food wholesalers and corner stores to improve the surrounding community’s access to healthy food. The objective of this article is to describe the development and implementation of BHCK’s corner store and wholesaler interventions through formal process evaluation. Researchers evaluated each level of the intervention to assess reach, dose delivered, and fidelity. Corner store and wholesaler reach, dose delivered, and fidelity were measured by number of interactions, promotional materials distributed, and maintenance of study materials, respectively. Overall, the corner store implementation showed moderate reach, dose delivered, and high fidelity. The wholesaler intervention was implemented with high reach, dose, and fidelity. The program held 355 corner store interactive sessions and had 9,347 community member interactions, 21% of which were with children between the ages of 10 and 14 years. There was a 15% increase in corner store promoted food stocking during Wave 1 and a 17% increase during Wave 2. These findings demonstrate a successfully implemented food retailer intervention in a low-income urban setting. PMID:28343413

High-Fidelity Simulation in Biomedical and Aerospace Engineering

NASA Technical Reports Server (NTRS)

Kwak, Dochan

2005-01-01

Contents include the following: Introduction / Background. Modeling and Simulation Challenges in Aerospace Engineering. Modeling and Simulation Challenges in Biomedical Engineering. Digital Astronaut. Project Columbia. Summary and Discussion.

The effect of model fidelity on prediction of char burnout for single-particle coal combustion

DOE PAGES

McConnell, Josh; Sutherland, James C.

2016-07-09

In this study, practical simulation of industrial-scale coal combustion relies on the ability to accurately capture the dynamics of coal subprocesses while also ensuring the computational cost remains reasonable. The majority of the residence time occurs post-devolatilization, so it is of great importance that a balance between the computational efficiency and accuracy of char combustion models is carefully considered. In this work, we consider the importance of model fidelity during char combustion by comparing combinations of simple and complex gas and particle-phase chemistry models. Detailed kinetics based on the GRI 3.0 mechanism and infinitely-fast chemistry are considered in the gas-phase.more » The Char Conversion Kinetics model and nth-Order Langmuir–Hinshelwood model are considered for char consumption. For devolatilization, the Chemical Percolation and Devolatilization and Kobayashi-Sarofim models are employed. The relative importance of gasification versus oxidation reactions in air and oxyfuel environments is also examined for various coal types. Results are compared to previously published experimental data collected under laminar, single-particle conditions. Calculated particle temperature histories are strongly dependent on the choice of gas phase and char chemistry models, but only weakly dependent on the chosen devolatilization model. Particle mass calculations were found to be very sensitive to the choice of devolatilization model, but only somewhat sensitive to the choice of gas chemistry and char chemistry models. High-fidelity models for devolatilization generally resulted in particle temperature and mass calculations that were closer to experimentally observed values.« less

The effect of model fidelity on prediction of char burnout for single-particle coal combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnell, Josh; Sutherland, James C.

In this study, practical simulation of industrial-scale coal combustion relies on the ability to accurately capture the dynamics of coal subprocesses while also ensuring the computational cost remains reasonable. The majority of the residence time occurs post-devolatilization, so it is of great importance that a balance between the computational efficiency and accuracy of char combustion models is carefully considered. In this work, we consider the importance of model fidelity during char combustion by comparing combinations of simple and complex gas and particle-phase chemistry models. Detailed kinetics based on the GRI 3.0 mechanism and infinitely-fast chemistry are considered in the gas-phase.more » The Char Conversion Kinetics model and nth-Order Langmuir–Hinshelwood model are considered for char consumption. For devolatilization, the Chemical Percolation and Devolatilization and Kobayashi-Sarofim models are employed. The relative importance of gasification versus oxidation reactions in air and oxyfuel environments is also examined for various coal types. Results are compared to previously published experimental data collected under laminar, single-particle conditions. Calculated particle temperature histories are strongly dependent on the choice of gas phase and char chemistry models, but only weakly dependent on the chosen devolatilization model. Particle mass calculations were found to be very sensitive to the choice of devolatilization model, but only somewhat sensitive to the choice of gas chemistry and char chemistry models. High-fidelity models for devolatilization generally resulted in particle temperature and mass calculations that were closer to experimentally observed values.« less

Tolerance for audiovisual asynchrony is enhanced by the spectrotemporal fidelity of the speaker's mouth movements and speech.

PubMed

Shahin, Antoine J; Shen, Stanley; Kerlin, Jess R

2017-01-01

We examined the relationship between tolerance for audiovisual onset asynchrony (AVOA) and the spectrotemporal fidelity of the spoken words and the speaker's mouth movements. In two experiments that only varied in the temporal order of sensory modality, visual speech leading (exp1) or lagging (exp2) acoustic speech, participants watched intact and blurred videos of a speaker uttering trisyllabic words and nonwords that were noise vocoded with 4-, 8-, 16-, and 32-channels. They judged whether the speaker's mouth movements and the speech sounds were in-sync or out-of-sync . Individuals perceived synchrony (tolerated AVOA) on more trials when the acoustic speech was more speech-like (8 channels and higher vs. 4 channels), and when visual speech was intact than blurred (exp1 only). These findings suggest that enhanced spectrotemporal fidelity of the audiovisual (AV) signal prompts the brain to widen the window of integration promoting the fusion of temporally distant AV percepts.

Quantum teleportation via noisy bipartite and tripartite accelerating quantum states: beyond the single mode approximation

NASA Astrophysics Data System (ADS)

Zounia, M.; Shamirzaie, M.; Ashouri, A.

2017-09-01

In this paper quantum teleportation of an unknown quantum state via noisy maximally bipartite (Bell) and maximally tripartite (Greenberger-Horne-Zeilinger (GHZ)) entangled states are investigated. We suppose that one of the observers who would receive the sent state accelerates uniformly with respect to the sender. The interactions of the quantum system with its environment during the teleportation process impose noises. These (unital and nonunital) noises are: phase damping, phase flip, amplitude damping and bit flip. In expressing the modes of the Dirac field used as qubits, in the accelerating frame, the so-called single mode approximation is not imposed. We calculate the fidelities of teleportation, and discuss their behaviors using suitable plots. The effects of noise, acceleration and going beyond the single mode approximation are discussed. Although the Bell states bring higher fidelities than GHZ states, the global behaviors of the two quantum systems with respect to some noise types, and therefore their fidelities, are different.

Updates on measurements and modeling techniques for expendable countermeasures

NASA Astrophysics Data System (ADS)

Gignilliat, Robert; Tepfer, Kathleen; Wilson, Rebekah F.; Taczak, Thomas M.

2016-10-01

The potential threat of recently-advertised anti-ship missiles has instigated research at the United States (US) Naval Research Laboratory (NRL) into the improvement of measurement techniques for visual band countermeasures. The goal of measurements is the collection of radiometric imagery for use in the building and validation of digital models of expendable countermeasures. This paper will present an overview of measurement requirements unique to the visual band and differences between visual band and infrared (IR) band measurements. A review of the metrics used to characterize signatures in the visible band will be presented and contrasted to those commonly used in IR band measurements. For example, the visual band measurements require higher fidelity characterization of the background, including improved high-transmittance measurements and better characterization of solar conditions to correlate results more closely with changes in the environment. The range of relevant engagement angles has also been expanded to include higher altitude measurements of targets and countermeasures. In addition to the discussion of measurement techniques, a top-level qualitative summary of modeling approaches will be presented. No quantitative results or data will be presented.

Observational learning from tool using models by human-reared and mother-reared capuchin monkeys (Cebus apella).

PubMed

Fredman, Tamar; Whiten, Andrew

2008-04-01

Studies of wild capuchins suggest an important role for social learning, but experiments with captive subjects have generally not supported this. Here we report social learning in two quite different populations of capuchin monkeys (Cebus apella). In experiment 1, human-raised monkeys observed a familiar human model open a foraging box using a tool in one of two alternative ways: levering versus poking. In experiment 2, mother-raised monkeys viewed similar techniques demonstrated by monkey models. A control group in each population saw no model. In both experiments, independent coders detected which technique experimental subjects had seen, thus confirming social learning. Further analyses examined fidelity of copying at three levels of resolution. The human-raised monkeys exhibited fidelity at the highest level, the specific tool use technique witnessed. The lever technique was seen only in monkeys exposed to a levering model, by contrast with controls and those witnessing poke. Mother-reared monkeys instead typically ignored the tool and exhibited fidelity at a lower level, tending only to re-create whichever result the model had achieved by either levering or poking. Nevertheless this level of social learning was associated with significantly greater levels of success in monkeys witnessing a model than in controls, an effect absent in the human-reared population. Results in both populations are consistent with a process of canalization of the repertoire in the direction of the approach witnessed, producing a narrower, socially shaped behavioural profile than among controls who saw no model.

The chicken foot digital replant training model.

PubMed

Athanassopoulos, Thanassi; Loh, Charles Yuen Yung

2015-01-01

A simple, readily available digital replantation model in the chicken foot is described. This high fidelity model will hopefully allow trainees in hand surgery to gain further experience in replant surgery prior to clinical application.

Objective Fidelity Evaluation in Multisensory Virtual Environments: Auditory Cue Fidelity in Flight Simulation

PubMed Central

Meyer, Georg F.; Wong, Li Ting; Timson, Emma; Perfect, Philip; White, Mark D.

2012-01-01

We argue that objective fidelity evaluation of virtual environments, such as flight simulation, should be human-performance-centred and task-specific rather than measure the match between simulation and physical reality. We show how principled experimental paradigms and behavioural models to quantify human performance in simulated environments that have emerged from research in multisensory perception provide a framework for the objective evaluation of the contribution of individual cues to human performance measures of fidelity. We present three examples in a flight simulation environment as a case study: Experiment 1: Detection and categorisation of auditory and kinematic motion cues; Experiment 2: Performance evaluation in a target-tracking task; Experiment 3: Transferrable learning of auditory motion cues. We show how the contribution of individual cues to human performance can be robustly evaluated for each task and that the contribution is highly task dependent. The same auditory cues that can be discriminated and are optimally integrated in experiment 1, do not contribute to target-tracking performance in an in-flight refuelling simulation without training, experiment 2. In experiment 3, however, we demonstrate that the auditory cue leads to significant, transferrable, performance improvements with training. We conclude that objective fidelity evaluation requires a task-specific analysis of the contribution of individual cues. PMID:22957068

The Fundamentals of Laparoscopic Surgery and LapVR evaluation metrics may not correlate with operative performance in a novice cohort

PubMed Central

Steigerwald, Sarah N.; Park, Jason; Hardy, Krista M.; Gillman, Lawrence; Vergis, Ashley S.

2015-01-01

Background Considerable resources have been invested in both low- and high-fidelity simulators in surgical training. The purpose of this study was to investigate if the Fundamentals of Laparoscopic Surgery (FLS, low-fidelity box trainer) and LapVR (high-fidelity virtual reality) training systems correlate with operative performance on the Global Operative Assessment of Laparoscopic Skills (GOALS) global rating scale using a porcine cholecystectomy model in a novice surgical group with minimal laparoscopic experience. Methods Fourteen postgraduate year 1 surgical residents with minimal laparoscopic experience performed tasks from the FLS program and the LapVR simulator as well as a live porcine laparoscopic cholecystectomy. Performance was evaluated using standardized FLS metrics, automatic computer evaluations, and a validated global rating scale. Results Overall, FLS score did not show an association with GOALS global rating scale score on the porcine cholecystectomy. None of the five LapVR task scores were significantly associated with GOALS score on the porcine cholecystectomy. Conclusions Neither the low-fidelity box trainer or the high-fidelity virtual simulator demonstrated significant correlation with GOALS operative scores. These findings offer caution against the use of these modalities for brief assessments of novice surgical trainees, especially for predictive or selection purposes. PMID:26641071

[Low Fidelity Simulation of a Zero-Y Robot

NASA Technical Reports Server (NTRS)

Sweet, Adam

2001-01-01

The item to be cleared is a low-fidelity software simulation model of a hypothetical freeflying robot designed for use in zero gravity environments. This simulation model works with the HCC simulation system that was developed by Xerox PARC and NASA Ames Research Center. HCC has been previously cleared for distribution. When used with the HCC software, the model computes the location and orientation of the simulated robot over time. Failures (such as a broken motor) can be injected into the simulation to produce simulated behavior corresponding to the failure. Release of this simulation will allow researchers to test their software diagnosis systems by attempting to diagnose the simulated failure from the simulated behavior. This model does not contain any encryption software nor can it perform any control tasks that might be export controlled.

Intervention Fidelity: Aspects of Complementary and Alternative Medicine (CAM) Research

PubMed Central

Wyatt, Gwen; Sikorskii, Alla; Rahbar, Mohammad Hossein; Victorson, David; Adams, Lora

2010-01-01

Background The Treatment Fidelity Workgroup (TFW) established by the National Institutes of Health (NIH) provides a 5-point structure for intervention fidelity: dosing, interventionists’ consistency, intervention delivery, receipt and enactment of the intervention. Using our reflexology trial, we apply the first three points. Objectives Study objectives are to: 1) evaluate key dosage dimensions associated with CAM research; 2) evaluate approaches to interventionists’ consistency of delivery of CAM protocols; and 3) evaluate and discuss data that reflect CAM intervention fidelity. Intervention Women with late stage breast cancer (N=318) were randomly assigned to either 4 weeks of reflexology, placebo, or standard care. Results Dosing consists of three dimensions: frequency (4-sessions), duration (30 minutes), and interval between sessions (5–9 days). Interventionist consistency revealed over a 90% accuracy rate in following the protocol; 84% and 89% completion rate of the 4 session in the reflexology and placebo groups respectively; and no differences in attrition after randomization between reflexology and placebo groups (17% and 15%, respectively). Intervention delivery, examined through debriefing data, indicated a significantly higher rate of correct guesses on group assignment in the reflexology group as compared to the placebo (82% versus 46%, p-value=.0002). Conclusions This study points out the relevance of dosing, interventionists’ consistency, and delivery data within a CAM clinical trial, as well as the challenges of blinding. Implications Monitoring intervention fidelity by using the key areas identified by the BCC ensures that findings from a clinical trial are meaningful and have the potential to be translated to clinical practice. PMID:20467309

Numerics and subgrid-scale modeling in large eddy simulations of stratocumulus clouds.

PubMed

Pressel, Kyle G; Mishra, Siddhartha; Schneider, Tapio; Kaul, Colleen M; Tan, Zhihong

2017-06-01

Stratocumulus clouds are the most common type of boundary layer cloud; their radiative effects strongly modulate climate. Large eddy simulations (LES) of stratocumulus clouds often struggle to maintain fidelity to observations because of the sharp gradients occurring at the entrainment interfacial layer at the cloud top. The challenge posed to LES by stratocumulus clouds is evident in the wide range of solutions found in the LES intercomparison based on the DYCOMS-II field campaign, where simulated liquid water paths for identical initial and boundary conditions varied by a factor of nearly 12. Here we revisit the DYCOMS-II RF01 case and show that the wide range of previous LES results can be realized in a single LES code by varying only the numerical treatment of the equations of motion and the nature of subgrid-scale (SGS) closures. The simulations that maintain the greatest fidelity to DYCOMS-II observations are identified. The results show that using weighted essentially non-oscillatory (WENO) numerics for all resolved advective terms and no explicit SGS closure consistently produces the highest-fidelity simulations. This suggests that the numerical dissipation inherent in WENO schemes functions as a high-quality, implicit SGS closure for this stratocumulus case. Conversely, using oscillatory centered difference numerical schemes for momentum advection, WENO numerics for scalars, and explicitly modeled SGS fluxes consistently produces the lowest-fidelity simulations. We attribute this to the production of anomalously large SGS fluxes near the cloud tops through the interaction of numerical error in the momentum field with the scalar SGS model.

Numerics and subgrid‐scale modeling in large eddy simulations of stratocumulus clouds

PubMed Central

Mishra, Siddhartha; Schneider, Tapio; Kaul, Colleen M.; Tan, Zhihong

2017-01-01

Abstract Stratocumulus clouds are the most common type of boundary layer cloud; their radiative effects strongly modulate climate. Large eddy simulations (LES) of stratocumulus clouds often struggle to maintain fidelity to observations because of the sharp gradients occurring at the entrainment interfacial layer at the cloud top. The challenge posed to LES by stratocumulus clouds is evident in the wide range of solutions found in the LES intercomparison based on the DYCOMS‐II field campaign, where simulated liquid water paths for identical initial and boundary conditions varied by a factor of nearly 12. Here we revisit the DYCOMS‐II RF01 case and show that the wide range of previous LES results can be realized in a single LES code by varying only the numerical treatment of the equations of motion and the nature of subgrid‐scale (SGS) closures. The simulations that maintain the greatest fidelity to DYCOMS‐II observations are identified. The results show that using weighted essentially non‐oscillatory (WENO) numerics for all resolved advective terms and no explicit SGS closure consistently produces the highest‐fidelity simulations. This suggests that the numerical dissipation inherent in WENO schemes functions as a high‐quality, implicit SGS closure for this stratocumulus case. Conversely, using oscillatory centered difference numerical schemes for momentum advection, WENO numerics for scalars, and explicitly modeled SGS fluxes consistently produces the lowest‐fidelity simulations. We attribute this to the production of anomalously large SGS fluxes near the cloud tops through the interaction of numerical error in the momentum field with the scalar SGS model. PMID:28943997

Tool for Generation of MAC/GMC Representative Unit Cell for CMC/PMC Analysis

NASA Technical Reports Server (NTRS)

Murthy, Pappu L. N.; Pineda, Evan J.

2016-01-01

This document describes a recently developed analysis tool that enhances the resident capabilities of the Micromechanics Analysis Code with the Generalized Method of Cells (MAC/GMC) 4.0. This tool is especially useful in analyzing ceramic matrix composites (CMCs), where higher fidelity with improved accuracy of local response is needed. The tool, however, can be used for analyzing polymer matrix composites (PMCs) as well. MAC/GMC 4.0 is a composite material and laminate analysis software developed at NASA Glenn Research Center. The software package has been built around the concept of the generalized method of cells (GMC). The computer code is developed with a user friendly framework, along with a library of local inelastic, damage, and failure models. Further, application of simulated thermomechanical loading, generation of output results, and selection of architectures to represent the composite material have been automated to increase the user friendliness, as well as to make it more robust in terms of input preparation and code execution. Finally, classical lamination theory has been implemented within the software, wherein GMC is used to model the composite material response of each ply. Thus, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. The primary focus of the current effort is to provide a graphical user interface (GUI) capability that generates a number of different user-defined repeating unit cells (RUCs). In addition, the code has provisions for generation of a MAC/GMC-compatible input text file that can be merged with any MAC/GMC input file tailored to analyze composite materials. Although the primary intention was to address the three different constituents and phases that are usually present in CMCs-namely, fibers, matrix, and interphase-it can be easily modified to address two-phase polymer matrix composite (PMC) materials where an interphase is absent. Currently, the tool capability includes generation of RUCs for square packing, hexagonal packing, and random fiber packing as well as RUCs based on actual composite micrographs. All these options have the fibers modeled as having a circular cross-sectional area. In addition, a simplified version of RUC is provided where the fibers are treated as having a square cross section and are distributed randomly. This RUC facilitates a speedy analysis using the higher fidelity version of GMC known as HFGMC. The first four mentioned options above support uniform subcell discretization. The last one has variable subcell sizes due to the primary intention of keeping the RUC size to a minimum to gain the speed ups using the higher fidelity version of MAC. The code is implemented within the MATLAB (The Mathworks, Inc., Natick, MA) developmental framework; however, a standalone application that does not need a priori MATLAB installation is also created with the aid of the MATLAB compiler.

High Fidelity Measurement and Modeling of Interactions between Acoustics and Heat Release in Highly-Compact, High-Pressure Flames

DTIC Science & Technology

2016-05-24

experimental data. However, the time and length scales, and energy deposition rates in the canonical laboratory flames that have been studied over the...is to obtain high-fidelity experimental data critically needed to validate research codes at relevant conditions, and to develop systematic and...validated with experimental data. However, the time and length scales, and energy deposition rates in the canonical laboratory flames that have been

High-Fidelity Computational Aerodynamics of the Elytron 4S UAV

NASA Technical Reports Server (NTRS)

Ventura Diaz, Patricia; Yoon, Seokkwan; Theodore, Colin R.

2018-01-01

High-fidelity Computational Fluid Dynamics (CFD) have been carried out for the Elytron 4S Unmanned Aerial Vehicle (UAV), also known as the converticopter "proto12". It is the scaled wind tunnel model of the Elytron 4S, an Urban Air Mobility (UAM) concept, a tilt-wing, box-wing rotorcraft capable of Vertical Take-Off and Landing (VTOL). The three-dimensional unsteady Navier-Stokes equations are solved on overset grids employing high-order accurate schemes, dual-time stepping, and a hybrid turbulence model using NASA's CFD code OVERFLOW. The Elytron 4S UAV has been simulated in airplane mode and in helicopter mode.

Application of a High-Fidelity Icing Analysis Method to a Model-Scale Rotor in Forward Flight

NASA Technical Reports Server (NTRS)

Narducci, Robert; Orr, Stanley; Kreeger, Richard E.

2012-01-01

An icing analysis process involving the loose coupling of OVERFLOW-RCAS for rotor performance prediction and with LEWICE3D for thermal analysis and ice accretion is applied to a model-scale rotor for validation. The process offers high-fidelity rotor analysis for the noniced and iced rotor performance evaluation that accounts for the interaction of nonlinear aerodynamics with blade elastic deformations. Ice accumulation prediction also involves loosely coupled data exchanges between OVERFLOW and LEWICE3D to produce accurate ice shapes. Validation of the process uses data collected in the 1993 icing test involving Sikorsky's Powered Force Model. Non-iced and iced rotor performance predictions are compared to experimental measurements as are predicted ice shapes.

Hand ultrasound: a high-fidelity simulation of lung sliding.

PubMed

Shokoohi, Hamid; Boniface, Keith

2012-09-01

Simulation training has been effectively used to integrate didactic knowledge and technical skills in emergency and critical care medicine. In this article, we introduce a novel model of simulating lung ultrasound and the features of lung sliding and pneumothorax by performing a hand ultrasound. The simulation model involves scanning the palmar aspect of the hand to create normal lung sliding in varying modes of scanning and to mimic ultrasound features of pneumothorax, including "stratosphere/barcode sign" and "lung point." The simple, reproducible, and readily available simulation model we describe demonstrates a high-fidelity simulation surrogate that can be used to rapidly illustrate the signs of normal and abnormal lung sliding at the bedside. © 2012 by the Society for Academic Emergency Medicine.

Modeling challenges and approaches in simulating the Jovian synchrotron radiation belts from an in-situ perspective

NASA Astrophysics Data System (ADS)

Adumitroaie, V.; Oyafuso, F. A.; Levin, S.; Gulkis, S.; Janssen, M. A.; Santos-Costa, D.; Bolton, S. J.

2017-12-01

In order to obtain credible atmospheric composition retrieval values from Jupiter's observed radiative signature via Juno's MWR instrument, it is necessary to separate as robustly as possible the contributions from three emission sources: CMB, planet and synchrotron radiation belts. The numerical separation requires a refinement, based on the in-situ data, of a higher fidelity model for the synchrotron emission, namely the multi-parameter, multi-zonal model of Levin at al. (2001). This model employs an empirical electron energy distribution, which prior to the Juno mission, has been adjusted exclusively from VLA observations. At minimum 8 sets of perijove observations (i.e. by PJ9) have to be delivered to an inverse model for retrieval of the electron distribution parameters with the goal of matching the synchrotron emission observed along MWR's lines of sight. The challenges and approaches taken to perform this task are discussed here. The model will be continuously improved with the availability of additional information, both from the MWR and magnetometer instruments.

A comparison of homogeneous equilibrium and relaxation model for CO2 expansion inside the two-phase ejector

NASA Astrophysics Data System (ADS)

Palacz, M.; Haida, M.; Smolka, J.; Nowak, A. J.; Hafner, A.

2016-09-01

In this study, the comparison of the accuracy of the homogeneous equilibrium model (HEM) and homogeneous relaxation model (HRM) is presented. Both models were applied to simulate the CO2 expansion inside the two-phase ejectors. Moreover, the mentioned models were implemented in the robust and efficient computational tool ejectorPL. That tool guarantees the fully automated computational process and the repeatable computations for the various ejector shapes and operating conditions. The simulated motive nozzle mass flow rates were compared to the experimentally measured mass flow rates. That comparison was made for both, HEM and HRM. The results showed the unsatisfying fidelity of the HEM for the operating regimes far from the carbon dioxide critical point. On the other hand, the HRM accuracy for such conditions was slightly higher. The approach presented in this paper, showed the limitation of applicability of both two-phase models for the expansion phenomena inside the ejectors.

The effect of visual and interaction fidelity on spatial cognition in immersive virtual environments.

PubMed

Mania, Katerina; Wooldridge, Dave; Coxon, Matthew; Robinson, Andrew

2006-01-01

Accuracy of memory performance per se is an imperfect reflection of the cognitive activity (awareness states) that underlies performance in memory tasks. The aim of this research is to investigate the effect of varied visual and interaction fidelity of immersive virtual environments on memory awareness states. A between groups experiment was carried out to explore the effect of rendering quality on location-based recognition memory for objects and associated states of awareness. The experimental space, consisting of two interconnected rooms, was rendered either flat-shaded or using radiosity rendering. The computer graphics simulations were displayed on a stereo head-tracked Head Mounted Display. Participants completed a recognition memory task after exposure to the experimental space and reported one of four states of awareness following object recognition. These reflected the level of visual mental imagery involved during retrieval, the familiarity of the recollection, and also included guesses. Experimental results revealed variations in the distribution of participants' awareness states across conditions while memory performance failed to reveal any. Interestingly, results revealed a higher proportion of recollections associated with mental imagery in the flat-shaded condition. These findings comply with similar effects revealed in two earlier studies summarized here, which demonstrated that the less "naturalistic" interaction interface or interface of low interaction fidelity provoked a higher proportion of recognitions based on visual mental images.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ragan, Eric D.; Bowman, Doug A.; Kopper, Regis

Virtual reality training systems are commonly used in a variety of domains, and it is important to understand how the realism of a training simulation influences training effectiveness. The paper presents a framework for evaluating the effects of virtual reality fidelity based on an analysis of a simulation’s display, interaction, and scenario components. Following this framework, we conducted a controlled experiment to test the effects of fidelity on training effectiveness for a visual scanning task. The experiment varied the levels of field of view and visual realism during a training phase and then evaluated scanning performance with the simulator’s highestmore » level of fidelity. To assess scanning performance, we measured target detection and adherence to a prescribed strategy. The results show that both field of view and visual realism significantly affected target detection during training; higher field of view led to better performance and higher visual realism worsened performance. Additionally, the level of visual realism during training significantly affected learning of the prescribed visual scanning strategy, providing evidence that high visual realism was important for learning the technique. The results also demonstrate that task performance during training was not always a sufficient measure of mastery of an instructed technique. That is, if learning a prescribed strategy or skill is the goal of a training exercise, performance in a simulation may not be an appropriate indicator of effectiveness outside of training—evaluation in a more realistic setting may be necessary.« less

PHYSICS OF ECLIPSING BINARIES. II. TOWARD THE INCREASED MODEL FIDELITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prša, A.; Conroy, K. E.; Horvat, M.

The precision of photometric and spectroscopic observations has been systematically improved in the last decade, mostly thanks to space-borne photometric missions and ground-based spectrographs dedicated to finding exoplanets. The field of eclipsing binary stars strongly benefited from this development. Eclipsing binaries serve as critical tools for determining fundamental stellar properties (masses, radii, temperatures, and luminosities), yet the models are not capable of reproducing observed data well, either because of the missing physics or because of insufficient precision. This led to a predicament where radiative and dynamical effects, insofar buried in noise, started showing up routinely in the data, but weremore » not accounted for in the models. PHOEBE (PHysics Of Eclipsing BinariEs; http://phoebe-project.org) is an open source modeling code for computing theoretical light and radial velocity curves that addresses both problems by incorporating missing physics and by increasing the computational fidelity. In particular, we discuss triangulation as a superior surface discretization algorithm, meshing of rotating single stars, light travel time effects, advanced phase computation, volume conservation in eccentric orbits, and improved computation of local intensity across the stellar surfaces that includes the photon-weighted mode, the enhanced limb darkening treatment, the better reflection treatment, and Doppler boosting. Here we present the concepts on which PHOEBE is built and proofs of concept that demonstrate the increased model fidelity.« less

Creation of a High-fidelity, Low-cost Pediatric Skull Fracture Ultrasound Phantom.

PubMed

Soucy, Zachary P; Mills, Lisa; Rose, John S; Kelley, Kenneth; Ramirez, Francisco; Kuppermann, Nathan

2015-08-01

Over the past decade, point-of-care ultrasound has become a common tool used for both procedures and diagnosis. Developing high-fidelity phantoms is critical for training in new and novel point-of-care ultrasound applications. Detecting skull fractures on ultrasound imaging in the younger-than-2-year-old patient is an emerging area of point-of-care ultrasound research. Identifying a skull fracture on ultrasound imaging in this age group requires knowledge of the appearance and location of sutures to distinguish them from fractures. There are currently no commercially available pediatric skull fracture models. We outline a novel approach to building a cost-effective, simple, high-fidelity pediatric skull fracture phantom to meet a unique training requirement. © 2015 by the American Institute of Ultrasound in Medicine.

Dynamic Behavior of Sand: Annual Report FY 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antoun, T; Herbold, E; Johnson, S

2012-03-15

Currently, design of earth-penetrating munitions relies heavily on empirical relationships to estimate behavior, making it difficult to design novel munitions or address novel target situations without expensive and time-consuming full-scale testing with relevant system and target characteristics. Enhancing design through numerical studies and modeling could help reduce the extent and duration of full-scale testing if the models have enough fidelity to capture all of the relevant parameters. This can be separated into three distinct problems: that of the penetrator structural and component response, that of the target response, and that of the coupling between the two. This project focuses onmore » enhancing understanding of the target response, specifically granular geomaterials, where the temporal and spatial multi-scale nature of the material controls its response. As part of the overarching goal of developing computational capabilities to predict the performance of conventional earth-penetrating weapons, this project focuses specifically on developing new models and numerical capabilities for modeling sand response in ALE3D. There is general recognition that granular materials behave in a manner that defies conventional continuum approaches which rely on response locality and which degrade in the presence of strong response nonlinearities, localization, and phase gradients. There are many numerical tools available to address parts of the problem. However, to enhance modeling capability, this project is pursuing a bottom-up approach of building constitutive models from higher fidelity, smaller spatial scale simulations (rather than from macro-scale observations of physical behavior as is traditionally employed) that are being augmented to address the unique challenges of mesoscale modeling of dynamically loaded granular materials. Through understanding response and sensitivity at the grain-scale, it is expected that better reduced order representations of response can be formulated at the continuum scale as illustrated in Figure 1 and Figure 2. The final result of this project is to implement such reduced order models in the ALE3D material library for general use.« less

Comparison of Multiscale Method of Cells-Based Models for Predicting Elastic Properties of Filament Wound C/C-SiC

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Fassin, Marek; Bednarcyk, Brett A.; Reese, Stefanie; Simon, Jaan-Willem

2017-01-01

Three different multiscale models, based on the method of cells (generalized and high fidelity) micromechanics models were developed and used to predict the elastic properties of C/C-SiC composites. In particular, the following multiscale modeling strategies were employed: Concurrent multiscale modeling of all phases using the generalized method of cells, synergistic (two-way coupling in space) multiscale modeling with the generalized method of cells, and hierarchical (one-way coupling in space) multiscale modeling with the high fidelity generalized method of cells. The three models are validated against data from a hierarchical multiscale finite element model in the literature for a repeating unit cell of C/C-SiC. Furthermore, the multiscale models are used in conjunction with classical lamination theory to predict the stiffness of C/C-SiC plates manufactured via a wet filament winding and liquid silicon infiltration process recently developed by the German Aerospace Institute.

Stable isotopes suggest low site fidelity in Bar-Headed Geese (Anser indicus) in Mongolia: Implications for disease transmission

USGS Publications Warehouse

Bridge, Eli S.; Kelly, Jeffrey F.; Xiangming Xiao,; Batbayar, Nyambayar; Natsagdorj, Tseveenmyadag; Hill, Nichola J.; Takekawa, John Y.; Hawkes, Lucy A.; Bishop, Charles M.; Butler, Patrick J.; Newman, Scott H.

2015-01-01

Population connectivity is an important consideration in studies of disease transmission and biological conservation, especially with regard to migratory species. Determining how and when different subpopulations intermingle during different phases of the annual cycle can help identify important geographical regions or features as targets for conservation efforts and can help inform our understanding of continental-scale disease transmission. In this study, stable isotopes of hydrogen and carbon in contour feathers were used to assess the degree of molt-site fidelity among Bar-headed Geese (Anser indicus) captured in north-central Mongolia. Samples were collected from actively molting Bar-headed Geese (n = 61), and some individual samples included both a newly grown feather (still in sheath) and an old, worn feather from the bird's previous molt (n = 21). Although there was no difference in mean hydrogen isotope ratios for the old and new feathers, the isotopic variance in old feathers was approximately three times higher than that of the new feathers, which suggests that these birds use different and geographically distant molting locations from year to year. To further test this conclusion, online data and modeling tools from the isoMAP website were used to generate probability landscapes for the origin of each feather. Likely molting locations were much more widespread for old feathers than for new feathers, which supports the prospect of low molt-site fidelity. This finding indicates that population connectivity would be greater than expected based on data from a single annual cycle, and that disease spread can be rapid even in areas like Mongolia where Bar-headed Geese generally breed in small isolated groups.

Spacecraft Internal Acoustic Environment Modeling

NASA Technical Reports Server (NTRS)

Chu, Shao-Sheng R.; Allen Christopher S.

2010-01-01

Acoustic modeling can be used to identify key noise sources, determine/analyze sub-allocated requirements, keep track of the accumulation of minor noise sources, and to predict vehicle noise levels at various stages in vehicle development, first with estimates of noise sources, later with experimental data. This paper describes the implementation of acoustic modeling for design purposes by incrementally increasing model fidelity and validating the accuracy of the model while predicting the noise of sources under various conditions. During FY 07, a simple-geometry Statistical Energy Analysis (SEA) model was developed and validated using a physical mockup and acoustic measurements. A process for modeling the effects of absorptive wall treatments and the resulting reverberation environment were developed. During FY 08, a model with more complex and representative geometry of the Orion Crew Module (CM) interior was built, and noise predictions based on input noise sources were made. A corresponding physical mockup was also built. Measurements were made inside this mockup, and comparisons were made with the model and showed excellent agreement. During FY 09, the fidelity of the mockup and corresponding model were increased incrementally by including a simple ventilation system. The airborne noise contribution of the fans was measured using a sound intensity technique, since the sound power levels were not known beforehand. This is opposed to earlier studies where Reference Sound Sources (RSS) with known sound power level were used. Comparisons of the modeling result with the measurements in the mockup showed excellent results. During FY 10, the fidelity of the mockup and the model were further increased by including an ECLSS (Environmental Control and Life Support System) wall, associated closeout panels, and the gap between ECLSS wall and mockup wall. The effect of sealing the gap and adding sound absorptive treatment to ECLSS wall were also modeled and validated.

Nucleobase but not Sugar Fidelity is Maintained in the Sabin I RNA-Dependent RNA Polymerase.

PubMed

Liu, Xinran; Musser, Derek M; Lee, Cheri A; Yang, Xiaorong; Arnold, Jamie J; Cameron, Craig E; Boehr, David D

2015-10-26

The Sabin I poliovirus live, attenuated vaccine strain encodes for four amino acid changes (i.e., D53N, Y73H, K250E, and T362I) in the RNA-dependent RNA polymerase (RdRp). We have previously shown that the T362I substitution leads to a lower fidelity RdRp, and viruses encoding this variant are attenuated in a mouse model of poliovirus. Given these results, it was surprising that the nucleotide incorporation rate and nucleobase fidelity of the Sabin I RdRp is similar to that of wild-type enzyme, although the Sabin I RdRp is less selective against nucleotides with modified sugar groups. We suggest that the other Sabin amino acid changes (i.e., D53N, Y73H, K250E) help to re-establish nucleotide incorporation rates and nucleotide discrimination near wild-type levels, which may be a requirement for the propagation of the virus and its efficacy as a vaccine strain. These results also suggest that the nucleobase fidelity of the Sabin I RdRp likely does not contribute to viral attenuation.

Comparison of Low-Thrust Control Laws for Application in Planetocentric Space

NASA Technical Reports Server (NTRS)

Falck, Robert D.; Sjauw, Waldy K.; Smith, David A.

2014-01-01

Recent interest at NASA for the application of solar electric propulsion for the transfer of significant payloads in cislunar space has led to the development of high-fidelity simulations of such missions. With such transfers involving transfer times on the order of months, simulation time can be significant. In the past, the examination of such missions typically began with the use of lower-fidelity trajectory optimization tools such as SEPSPOT to develop and tune guidance laws which delivered optimal or near- optimal trajectories, where optimal is generally defined as minimizing propellant expenditure or time of flight. The transfer of these solutions to a high-fidelity simulation is typically an iterative process whereby the initial solution may nearly, but not precisely, meet mission objectives. Further tuning of the guidance algorithm is typically necessary when accounting for high-fidelity perturbations such as those due to more detailed gravity models, secondary-body effects, solar radiation pressure, etc. While trajectory optimization is a useful method for determining optimal performance metrics, algorithms which deliver nearly optimal performance with minimal tuning are an attractive alternative.

High-Fidelity Buckling Analysis of Composite Cylinders Using the STAGS Finite Element Code

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.

2014-01-01

Results from previous shell buckling studies are presented that illustrate some of the unique and powerful capabilities in the STAGS finite element analysis code that have made it an indispensable tool in structures research at NASA over the past few decades. In particular, prototypical results from the development and validation of high-fidelity buckling simulations are presented for several unstiffened thin-walled compression-loaded graphite-epoxy cylindrical shells along with a discussion on the specific methods and user-defined subroutines in STAGS that are used to carry out the high-fidelity simulations. These simulations accurately account for the effects of geometric shell-wall imperfections, shell-wall thickness variations, local shell-wall ply-gaps associated with the fabrication process, shell-end geometric imperfections, nonuniform applied end loads, and elastic boundary conditions. The analysis procedure uses a combination of nonlinear quasi-static and transient dynamic solution algorithms to predict the prebuckling and unstable collapse response characteristics of the cylinders. Finally, the use of high-fidelity models in the development of analysis-based shell-buckling knockdown (design) factors is demonstrated.

Modeling Pilot Behavior for Assessing Integrated Alert and Notification Systems on Flight Decks

NASA Technical Reports Server (NTRS)

Cover, Mathew; Schnell, Thomas

2010-01-01

Numerous new flight deck configurations for caution, warning, and alerts can be conceived; yet testing them with human-in-the-Ioop experiments to evaluate each one would not be practical. New sensors, instruments, and displays are being put into cockpits every day and this is particularly true as we enter the dawn of the Next Generation Air Transportation System (NextGen). By modeling pilot behavior in a computer simulation, an unlimited number of unique caution, warning, and alert configurations can be evaluated 24/7 by a computer. These computer simulations can then identify the most promising candidate formats to further evaluate in higher fidelity, but more costly, Human-in-the-Ioop (HITL) simulations. Evaluations using batch simulations with human performance models saves time, money, and enables a broader consideration of possible caution, warning, and alerting configurations for future flight decks.

Thermal Analysis of Small Re-Entry Probe

NASA Technical Reports Server (NTRS)

Agrawal, Parul; Prabhu, Dinesh K.; Chen, Y. K.

2012-01-01

The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test.

Extension of HCDstruct for Transonic Aeroservoelastic Analysis of Unconventional Aircraft Concepts

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; Gern, Frank H.

2017-01-01

A substantial effort has been made to implement an enhanced aerodynamic modeling capability in the Higher-fidelity Conceptual Design and structural optimization tool. This additional capability is needed for a rapid, physics-based method of modeling advanced aircraft concepts at risk of structural failure due to dynamic aeroelastic instabilities. To adequately predict these instabilities, in particular for transonic applications, a generalized aerodynamic matching algorithm was implemented to correct the doublet-lattice model available in Nastran using solution data from a priori computational fluid dynamics anal- ysis. This new capability is demonstrated for two tube-and-wing aircraft configurations, including a Boeing 737-200 for implementation validation and the NASA D8 as a first use case. Results validate the current implementation of the aerodynamic matching utility and demonstrate the importance of using such a method for aircraft configurations featuring fuselage-wing aerodynamic interaction.

Experimental Evaluation of Tuned Chamber Core Panels for Payload Fairing Noise Control

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Allen, Albert R.; Herlan, Jonathan W.; Rosenthal, Bruce N.

2015-01-01

Analytical models have been developed to predict the sound absorption and sound transmission loss of tuned chamber core panels. The panels are constructed of two facesheets sandwiching a corrugated core. When ports are introduced through one facesheet, the long chambers within the core can be used as an array of low-frequency acoustic resonators. To evaluate the accuracy of the analytical models, absorption and sound transmission loss tests were performed on flat panels. Measurements show that the acoustic resonators embedded in the panels improve both the absorption and transmission loss of the sandwich structure at frequencies near the natural frequency of the resonators. Analytical predictions for absorption closely match measured data. However, transmission loss predictions miss important features observed in the measurements. This suggests that higher-fidelity analytical or numerical models will be needed to supplement transmission loss predictions in the future.

Further Investigations of Gravity Modeling on Surface-Interacting Vehicle Simulations

NASA Technical Reports Server (NTRS)

Madden, Michael M.

2009-01-01

A vehicle simulation is "surface-interacting" if the state of the vehicle (position, velocity, and acceleration) relative to the surface is important. Surface-interacting simulations perform ascent, entry, descent, landing, surface travel, or atmospheric flight. The dynamics of surface-interacting simulations are influenced by the modeling of gravity. Gravity is the sum of gravitation and the centrifugal acceleration due to the world s rotation. Both components are functions of position relative to the world s center and that position for a given set of geodetic coordinates (latitude, longitude, and altitude) depends on the world model (world shape and dynamics). Thus, gravity fidelity depends on the fidelities of the gravitation model and the world model and on the interaction of the gravitation and world model. A surface-interacting simulation cannot treat the gravitation separately from the world model. This paper examines the actual performance of different pairs of world and gravitation models (or direct gravity models) on the travel of a subsonic civil transport in level flight under various starting conditions.

Comparison of the UAF Ionosphere Model with Incoherent-Scatter Radar Data

NASA Astrophysics Data System (ADS)

McAllister, J.; Maurits, S.; Kulchitsky, A.; Watkins, B.

2004-12-01

The UAF Eulerian Parallel Polar Ionosphere Model (UAF EPPIM) is a first-principles three-dimensional time-dependent representation of the northern polar ionosphere (>50 degrees north latitude). The model routinely generates short-term (~2 hours) ionospheric forecasts in real-time. It may also be run in post-processing/batch mode for specific time periods, including long-term (multi-year) simulations. The model code has been extensively validated (~100k comparisons/model year) against ionosonde foF2 data during quiet and moderate solar activity in 2002-2004 with reasonable fidelity (typical relative RMS 10-20% for summer daytime, 30-50% winter nighttime). However, ionosonde data is frequently not available during geomagnetic disturbances. The objective of the work reported here is to compare model outputs with available incoherent-scatter radar data during the storm period of October-November 2003. Model accuracy is examined for this period and compared to model performance during geomagnetically quiet and moderate circumstances. Possible improvements are suggested which are likely to boost model fidelity during storm conditions.

Gravity Modeling Effects on Surface-Interacting Vehicles in Supersonic Flight

NASA Technical Reports Server (NTRS)

Madden, Michael M.

2010-01-01

A vehicle simulation is "surface-interacting" if the state of the vehicle (position, velocity, and acceleration) relative to the surface is important. Surface-interacting simulations per-form ascent, entry, descent, landing, surface travel, or atmospheric flight. The dynamics of surface-interacting simulations are influenced by the modeling of gravity. Gravity is the sum of gravitation and the centrifugal acceleration due to the world s rotation. Both components are functions of position relative to the world s center and that position for a given set of geodetic coordinates (latitude, longitude, and altitude) depends on the world model (world shape and dynamics). Thus, gravity fidelity depends on the fidelities of the gravitation model and the world model and on the interaction of these two models. A surface-interacting simulation cannot treat gravitation separately from the world model. This paper examines the actual performance of different pairs of world and gravitation models (or direct gravity models) on the travel of a supersonic aircraft in level flight under various start-ing conditions.

Wind Farm Flow Modeling using an Input-Output Reduced-Order Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Gebraad, Pieter; Seiler, Peter

Wind turbines in a wind farm operate individually to maximize their own power regardless of the impact of aerodynamic interactions on neighboring turbines. There is the potential to increase power and reduce overall structural loads by properly coordinating turbines. To perform control design and analysis, a model needs to be of low computational cost, but retains the necessary dynamics seen in high-fidelity models. The objective of this work is to obtain a reduced-order model that represents the full-order flow computed using a high-fidelity model. A variety of methods, including proper orthogonal decomposition and dynamic mode decomposition, can be used tomore » extract the dominant flow structures and obtain a reduced-order model. In this paper, we combine proper orthogonal decomposition with a system identification technique to produce an input-output reduced-order model. This technique is used to construct a reduced-order model of the flow within a two-turbine array computed using a large-eddy simulation.« less

A Modular Approach to Model Oscillating Control Surfaces Using Navier Stokes Equations

NASA Technical Reports Server (NTRS)

Guruswamy, Guru P.; Lee, Henry

2014-01-01

The use of active controls for rotorcraft is becoming more important for modern aerospace configurations. Efforts to reduce the vibrations of helicopter blades with use of active-controls are in progress. Modeling oscillating control surfaces using the linear aerodynamics theory is well established. However, higher-fidelity methods are needed to account for nonlinear effects, such as those that occur in transonic flow. The aeroelastic responses of a wing with an oscillating control surface, computed using the transonic small perturbation (TSP) theory, have been shown to cause important transonic flow effects such as a reversal of control surface effectiveness that occurs as the shock wave crosses the hinge line. In order to account for flow complexities such as blade-vortex interactions of rotor blades higher-fidelity methods based on the Navier-Stokes equations are used. Reference 6 presents a procedure that uses the Navier-Stokes equations with moving-sheared grids and demonstrates up to 8 degrees of control-surface amplitude, using a single grid. Later, this procedure was extended to accommodate larger amplitudes, based on sliding grid zones. The sheared grid method implemented in EulerlNavier-Stokes-based aeroelastic code ENS AERO was successfully applied to active control design by industry. Recently there are several papers that present results for oscillating control surface using Reynolds Averaged Navier-Stokes (RANS) equations. References 9 and 10 report 2-D cases by filling gaps with overset grids. Reference 9 compares integrated forces with the experiment at low oscillating frequencies whereas Ref. 10 reports parametric studies but with no validation. Reference II reports results for a 3D case by modeling the gap region with a deformed grid and compares force results with the experiment only at the mid-span of flap. In Ref. II grid is deformed to match the control surface deflections at the section where the measurements are made. However, there is no indication in Ref. II that the gaps are explicitly modeled as in Ref. 6. Computations using overset grids are reported in Ref. 12 for a case by adding moving control surface to an existing blade but with no validation either with an experiment or another computation.

Validation of a Low-Thrust Mission Design Tool Using Operational Navigation Software

NASA Technical Reports Server (NTRS)

Englander, Jacob A.; Knittel, Jeremy M.; Williams, Ken; Stanbridge, Dale; Ellison, Donald H.

2017-01-01

Design of flight trajectories for missions employing solar electric propulsion requires a suitably high-fidelity design tool. In this work, the Evolutionary Mission Trajectory Generator (EMTG) is presented as a medium-high fidelity design tool that is suitable for mission proposals. EMTG is validated against the high-heritage deep-space navigation tool MIRAGE, demonstrating both the accuracy of EMTG's model and an operational mission design and navigation procedure using both tools. The validation is performed using a benchmark mission to the Jupiter Trojans.

Persistent model order reduction for complex dynamical systems using smooth orthogonal decomposition

NASA Astrophysics Data System (ADS)

Ilbeigi, Shahab; Chelidze, David

2017-11-01

Full-scale complex dynamic models are not effective for parametric studies due to the inherent constraints on available computational power and storage resources. A persistent reduced order model (ROM) that is robust, stable, and provides high-fidelity simulations for a relatively wide range of parameters and operating conditions can provide a solution to this problem. The fidelity of a new framework for persistent model order reduction of large and complex dynamical systems is investigated. The framework is validated using several numerical examples including a large linear system and two complex nonlinear systems with material and geometrical nonlinearities. While the framework is used for identifying the robust subspaces obtained from both proper and smooth orthogonal decompositions (POD and SOD, respectively), the results show that SOD outperforms POD in terms of stability, accuracy, and robustness.

Virtual Reality Compared with Bench-Top Simulation in the Acquisition of Arthroscopic Skill: A Randomized Controlled Trial.

PubMed

Banaszek, Daniel; You, Daniel; Chang, Justues; Pickell, Michael; Hesse, Daniel; Hopman, Wilma M; Borschneck, Daniel; Bardana, Davide

2017-04-05

Work-hour restrictions as set forth by the Accreditation Council for Graduate Medical Education (ACGME) and other governing bodies have forced training programs to seek out new learning tools to accelerate acquisition of both medical skills and knowledge. As a result, competency-based training has become an important part of residency training. The purpose of this study was to directly compare arthroscopic skill acquisition in both high-fidelity and low-fidelity simulator models and to assess skill transfer from either modality to a cadaveric specimen, simulating intraoperative conditions. Forty surgical novices (pre-clerkship-level medical students) voluntarily participated in this trial. Baseline demographic data, as well as data on arthroscopic knowledge and skill, were collected prior to training. Subjects were randomized to 5-week independent training sessions on a high-fidelity virtual reality arthroscopic simulator or on a bench-top arthroscopic setup, or to an untrained control group. Post-training, subjects were asked to perform a diagnostic arthroscopy on both simulators and in a simulated intraoperative environment on a cadaveric knee. A more difficult surprise task was also incorporated to evaluate skill transfer. Subjects were evaluated using the Global Rating Scale (GRS), the 14-point arthroscopic checklist, and a timer to determine procedural efficiency (time per task). Secondary outcomes focused on objective measures of virtual reality simulator motion analysis. Trainees on both simulators demonstrated a significant improvement (p < 0.05) in arthroscopic skills compared with baseline scores and untrained controls, both in and ex vivo. The virtual reality simulation group consistently outperformed the bench-top model group in the diagnostic arthroscopy crossover tests and in the simulated cadaveric setup. Furthermore, the virtual reality group demonstrated superior skill transfer in the surprise skill transfer task. Both high-fidelity and low-fidelity simulation trainings were effective in arthroscopic skill acquisition. High-fidelity virtual reality simulation was superior to bench-top simulation in the acquisition of arthroscopic skills, both in the laboratory and in vivo. Further clinical investigation is needed to interpret the importance of these results.

WEC3: Wave Energy Converter Code Comparison Project: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combourieu, Adrien; Lawson, Michael; Babarit, Aurelien

This paper describes the recently launched Wave Energy Converter Code Comparison (WEC3) project and present preliminary results from this effort. The objectives of WEC3 are to verify and validate numerical modelling tools that have been developed specifically to simulate wave energy conversion devices and to inform the upcoming IEA OES Annex VI Ocean Energy Modelling Verification and Validation project. WEC3 is divided into two phases. Phase 1 consists of a code-to-code verification and Phase II entails code-to-experiment validation. WEC3 focuses on mid-fidelity codes that simulate WECs using time-domain multibody dynamics methods to model device motions and hydrodynamic coefficients to modelmore » hydrodynamic forces. Consequently, high-fidelity numerical modelling tools, such as Navier-Stokes computational fluid dynamics simulation, and simple frequency domain modelling tools were not included in the WEC3 project.« less

Revisiting low-fidelity two-fluid models for gas–solids transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeleke, Najeem, E-mail: najm@psu.edu; Adewumi, Michael, E-mail: m2a@psu.edu; Ityokumbul, Thaddeus

Two-phase gas–solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas–solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The modelmore » equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe–Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.« less

Rectal Carcinoma Model: A Novel Simulation in Pathology Training.

PubMed

Pongpaibul, Ananya; Chiravirakul, Prattana; Leksrisakul, Piyawadee; Silakorn, Phadungsak; Chumtap, Wangcha; Chongpipatchaipron, Somchai; Jaitrong, Peerasak; Jitvichai, Ekachai

2017-06-01

Until now, the apprenticeship training model is used to train pathology residents. Pathology residents are trained using patient specimens that are received during the course of normal daily pathology service. However, this training method could result in inconsistency in knowledge and experience among trainees because of variation in specimens that are received for analysis. The use of simulated specimens in pathology residency training could help ensure that all pathology residents receive consistent knowledge and experience. The aim of this study was to develop prototype rectal carcinoma model to be used as a simulation tool and to evaluate its effectiveness in pathology training. Five units of a prototype rectal carcinoma model were produced in latex rubber. The model was used as a simulation tool for training in 12 pathology residents and 7 pathologist assistants. Pretesting and posttesting of each participant was conducted by multiple choice question test. A questionnaire was also given to study participants to elicit their views regarding the fidelity of the model and the model's efficacy and usefulness relative to the gross examination technique. Among the 19 participants, the mean pretest score was 79.24% and the mean posttest score was 88.54% (P = 0.045). The fidelity of the model was rated as moderate to marked by all participants. Most participants (94.74%) rated the models efficacy and usefulness relative to the gross examination technique as being moderate to marked. The rectal carcinoma model introduced in this study was found to be an effective simulation tool for pathology training. The model had good fidelity on appearance and good efficacy as well as usefulness relative to the gross examination technique.

Contextual Compression of Large-Scale Wind Turbine Array Simulations: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruchalla, Kenny M; Brunhart-Lupo, Nicholas J; Potter, Kristin C

Data sizes are becoming a critical issue particularly for HPC applications. We have developed a user-driven lossy wavelet-based storage model to facilitate the analysis and visualization of large-scale wind turbine array simulations. The model stores data as heterogeneous blocks of wavelet coefficients, providing high-fidelity access to user-defined data regions believed the most salient, while providing lower-fidelity access to less salient regions on a block-by-block basis. In practice, by retaining the wavelet coefficients as a function of feature saliency, we have seen data reductions in excess of 94 percent, while retaining lossless information in the turbine-wake regions most critical to analysismore » and providing enough (low-fidelity) contextual information in the upper atmosphere to track incoming coherent turbulent structures. Our contextual wavelet compression approach has allowed us to deliver interactive visual analysis while providing the user control over where data loss, and thus reduction in accuracy, in the analysis occurs. We argue this reduced but contexualized representation is a valid approach and encourages contextual data management.« less

Contextual Compression of Large-Scale Wind Turbine Array Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruchalla, Kenny M; Brunhart-Lupo, Nicholas J; Potter, Kristin C

Data sizes are becoming a critical issue particularly for HPC applications. We have developed a user-driven lossy wavelet-based storage model to facilitate the analysis and visualization of large-scale wind turbine array simulations. The model stores data as heterogeneous blocks of wavelet coefficients, providing high-fidelity access to user-defined data regions believed the most salient, while providing lower-fidelity access to less salient regions on a block-by-block basis. In practice, by retaining the wavelet coefficients as a function of feature saliency, we have seen data reductions in excess of 94 percent, while retaining lossless information in the turbine-wake regions most critical to analysismore » and providing enough (low-fidelity) contextual information in the upper atmosphere to track incoming coherent turbulent structures. Our contextual wavelet compression approach has allowed us to deliver interative visual analysis while providing the user control over where data loss, and thus reduction in accuracy, in the analysis occurs. We argue this reduced but contextualized representation is a valid approach and encourages contextual data management.« less

Monogamy relation in multipartite continuous-variable quantum teleportation

NASA Astrophysics Data System (ADS)

Lee, Jaehak; Ji, Se-Wan; Park, Jiyong; Nha, Hyunchul

2016-12-01

Quantum teleportation (QT) is a fundamentally remarkable communication protocol that also finds many important applications for quantum informatics. Given a quantum entangled resource, it is crucial to know to what extent one can accomplish the QT. This is usually assessed in terms of output fidelity, which can also be regarded as an operational measure of entanglement. In the case of multipartite communication when each communicator possesses a part of an N -partite entangled state, not all pairs of communicators can achieve a high fidelity due to the monogamy property of quantum entanglement. We here investigate how such a monogamy relation arises in multipartite continuous-variable (CV) teleportation, particularly when using a Gaussian entangled state. We show a strict monogamy relation, i.e., a sender cannot achieve a fidelity higher than optimal cloning limit with more than one receiver. While this seems rather natural owing to the no-cloning theorem, a strict monogamy relation still holds even if the sender is allowed to individually manipulate the reduced state in collaboration with each receiver to improve fidelity. The local operations are further extended to non-Gaussian operations such as photon subtraction and addition, and we demonstrate that the Gaussian cloning bound cannot be beaten by more than one pair of communicators. Furthermore, we investigate a quantitative form of monogamy relation in terms of teleportation capability, for which we show that a faithful monogamy inequality does not exist.

Minimally complex ion traps as modules for quantum communication and computing

NASA Astrophysics Data System (ADS)

Nigmatullin, Ramil; Ballance, Christopher J.; de Beaudrap, Niel; Benjamin, Simon C.

2016-10-01

Optically linked ion traps are promising as components of network-based quantum technologies, including communication systems and modular computers. Experimental results achieved to date indicate that the fidelity of operations within each ion trap module will be far higher than the fidelity of operations involving the links; fortunately internal storage and processing can effectively upgrade the links through the process of purification. Here we perform the most detailed analysis to date on this purification task, using a protocol which is balanced to maximise fidelity while minimising the device complexity and the time cost of the process. Moreover we ‘compile down’ the quantum circuit to device-level operations including cooling and shuttling events. We find that a linear trap with only five ions (two of one species, three of another) can support our protocol while incorporating desirable features such as global control, i.e. laser control pulses need only target an entire zone rather than differentiating one ion from its neighbour. To evaluate the capabilities of such a module we consider its use both as a universal communications node for quantum key distribution, and as the basic repeating unit of a quantum computer. For the latter case we evaluate the threshold for fault tolerant quantum computing using the surface code, finding acceptable fidelities for the ‘raw’ entangling link as low as 83% (or under 75% if an additional ion is available).

Ribosomal protein methyltransferases in the yeast Saccharomyces cerevisiae: Roles in ribosome biogenesis and translation.

PubMed

Al-Hadid, Qais; White, Jonelle; Clarke, Steven

2016-02-12

A significant percentage of the methyltransferasome in Saccharomyces cerevisiae and higher eukaryotes is devoted to methylation of the translational machinery. Methylation of the RNA components of the translational machinery has been studied extensively and is important for structure stability, ribosome biogenesis, and translational fidelity. However, the functional effects of ribosomal protein methylation by their cognate methyltransferases are still largely unknown. Previous work has shown that the ribosomal protein Rpl3 methyltransferase, histidine protein methyltransferase 1 (Hpm1), is important for ribosome biogenesis and translation elongation fidelity. In this study, yeast strains deficient in each of the ten ribosomal protein methyltransferases in S. cerevisiae were examined for potential defects in ribosome biogenesis and translation. Like Hpm1-deficient cells, loss of four of the nine other ribosomal protein methyltransferases resulted in defects in ribosomal subunit synthesis. All of the mutant strains exhibited resistance to the ribosome inhibitors anisomycin and/or cycloheximide in plate assays, but not in liquid culture. Translational fidelity assays measuring stop codon readthrough, amino acid misincorporation, and programmed -1 ribosomal frameshifting, revealed that eight of the ten enzymes are important for translation elongation fidelity and the remaining two are necessary for translation termination efficiency. Altogether, these results demonstrate that ribosomal protein methyltransferases in S. cerevisiae play important roles in ribosome biogenesis and translation. Copyright © 2016 Elsevier Inc. All rights reserved.

Investigation of Control Inceptor Dynamics and Effect on Human Subject Performance

NASA Technical Reports Server (NTRS)

Stanco, Anthony A.; Cardullo, Frank M.; Houck, Jacob A.; Grube, Richard C.; Kelly, Lon C.

2013-01-01

The control inceptor used in a vehicle simulation is an important part of adequately representing the dynamics of the vehicle. The inceptor characteristics are typically based on a second order spring mass damper system with damping, force gradient, breakout force, and natural frequency parameters. Changing these parameters can have a great effect on pilot control of the vehicle. A quasi transfer of training experiment was performed employing a high fidelity and a low fidelity control inceptor. A disturbance compensatory task was employed which involved a simple horizon line disturbed in roll by a sum of sinusoids presented in an out-the-window display. Vehicle dynamics were modeled as 1/s and 1/s2. The task was to maintain level flight. Twenty subjects were divided between the high and the low fidelity training groups. Each group was trained to a performance asymptote, and then transferred to the high fidelity simulation. RMS tracking error, a PSD analysis, and a workload analysis were performed to quantify the transfer of training effect. Quantitative results of the experiments show that there is no significant difference between the high and low fidelity training groups for 1/s plant dynamics. For 1/s2 plant dynamics there is a greater difference in tracking performance and PSD; and the subjects are less correlated with the input disturbance function

A Prenatal Coparenting Intervention With Unmarried Father-Mother Dyads: Fidelity of Intervention Delivery by Male-Female Community Mentor Teams.

PubMed

Salman-Engin, Selin; Little, Tara; Gaskin-Butler, Vikki; McHale, James P

2017-06-01

Most prenatal preventive interventions for unmarried mothers do not integrate fathers or help the parents plan for the development of a functional coparenting alliance after the baby's arrival. Furthermore, properly trained professionals have only rarely examined the fidelity of these interventions. This report examines whether experienced community interventionists (home visitors, health educators, fatherhood service personnel) with no formal couples' therapy training are capable of pairing together to deliver with adequate fidelity a manualized dyadic intervention designed for expectant unmarried mothers and fathers. Three male and four female mentors (home visitors, health educators, fatherhood personnel) working in paired male-female co-mentor teams delivered a seven-session "Figuring It Out for the Child" curriculum (six prenatal sessions, one booster) to 14 multirisk, unmarried African American families (parent age ranging from 14 to 40). Parental well-being and views of fatherhood were assessed before the intervention and again 3 months after the baby's birth. Quality assurance analysts evaluated mentor fidelity (adherence to the curriculum, competence in engaging couples with specified curricular content) through a review of the transcripts and audiotapes from the sessions. Mentors also rated their own adherence. Although the mentors overestimated adherence, quality assurance analyst ratings found acceptable levels of adherence and competence, with no significant male-female differences in fidelity. Adherence and competence were marginally higher in sessions that required fewer direct couples' interventions. Parents reported satisfaction with the interventions and showed statistically significant improvement in the family dimensions of interest at 3-4 months posttreatment. Findings support the wisdom of engaging men both as interventionists and as recipients of prenatal coparenting interventions-even in families where the parents are uncoupled and non-co-residential.

Structure, Function, and Propagation of Information across Living Two, Four, and Eight Node Degree Topologies.

PubMed

Alagapan, Sankaraleengam; Franca, Eric; Pan, Liangbin; Leondopulos, Stathis; Wheeler, Bruce C; DeMarse, Thomas B

2016-01-01

In this study, we created four network topologies composed of living cortical neurons and compared resultant structural-functional dynamics including the nature and quality of information transmission. Each living network was composed of living cortical neurons and were created using microstamping of adhesion promoting molecules and each was "designed" with different levels of convergence embedded within each structure. Networks were cultured over a grid of electrodes that permitted detailed measurements of neural activity at each node in the network. Of the topologies we tested, the "Random" networks in which neurons connect based on their own intrinsic properties transmitted information embedded within their spike trains with higher fidelity relative to any other topology we tested. Within our patterned topologies in which we explicitly manipulated structure, the effect of convergence on fidelity was dependent on both topology and time-scale (rate vs. temporal coding). A more detailed examination using tools from network analysis revealed that these changes in fidelity were also associated with a number of other structural properties including a node's degree, degree-degree correlations, path length, and clustering coefficients. Whereas information transmission was apparent among nodes with few connections, the greatest transmission fidelity was achieved among the few nodes possessing the highest number of connections (high degree nodes or putative hubs). These results provide a unique view into the relationship between structure and its affect on transmission fidelity, at least within these small neural populations with defined network topology. They also highlight the potential role of tools such as microstamp printing and microelectrode array recordings to construct and record from arbitrary network topologies to provide a new direction in which to advance the study of structure-function relationships.

Three-dimensional fuel pin model validation by prediction of hydrogen distribution in cladding and comparison with experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aly, A.; Avramova, Maria; Ivanov, Kostadin

To correctly describe and predict this hydrogen distribution there is a need for multi-physics coupling to provide accurate three-dimensional azimuthal, radial, and axial temperature distributions in the cladding. Coupled high-fidelity reactor-physics codes with a sub-channel code as well as with a computational fluid dynamics (CFD) tool have been used to calculate detailed temperature distributions. These high-fidelity coupled neutronics/thermal-hydraulics code systems are coupled further with the fuel-performance BISON code with a kernel (module) for hydrogen. Both hydrogen migration and precipitation/dissolution are included in the model. Results from this multi-physics analysis is validated utilizing calculations of hydrogen distribution using models informed bymore » data from hydrogen experiments and PIE data.« less

Evaluating Fidelity: Predictive Validity for a Measure of Competent Adherence to the Oregon Model of Parent Management Training

PubMed Central

Forgatch, Marion S.; Patterson, Gerald R.; DeGarmo, David S.

2006-01-01

When efficacious interventions are implemented in real-world conditions, it is important to evaluate whether or not the programs are practiced as intended. This article presents the Fidelity of Implementation Rating System (FIMP), an observation-based measure assessing competent adherence to the Oregon model of Parent Management Training (PMTO). FIMP evaluates 5 dimensions of competent adherence to PMTO (i.e., knowledge, structure, teaching skill, clinical skill, and overall effectiveness) specified in the intervention model. Predictive validity for FIMP was evaluated with a subsample of stepfamilies participating in a preventive PMTO intervention. As hypothesized, high FIMP ratings predicted change in observed parenting practices from baseline to 12 months. The rigor and scope of adherence measures are discussed. PMID:16718302

Waste IPSC : Thermal-Hydrologic-Chemical-Mechanical (THCM) modeling and simulation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeze, Geoffrey A.; Wang, Yifeng; Arguello, Jose Guadalupe, Jr.

2010-10-01

Waste IPSC Objective is to develop an integrated suite of high performance computing capabilities to simulate radionuclide movement through the engineered components and geosphere of a radioactive waste storage or disposal system: (1) with robust thermal-hydrologic-chemical-mechanical (THCM) coupling; (2) for a range of disposal system alternatives (concepts, waste form types, engineered designs, geologic settings); (3) for long time scales and associated large uncertainties; (4) at multiple model fidelities (sub-continuum, high-fidelity continuum, PA); and (5) in accordance with V&V and software quality requirements. THCM Modeling collaborates with: (1) Other Waste IPSC activities: Sub-Continuum Processes (and FMM), Frameworks and Infrastructure (and VU,more » ECT, and CT); (2) Waste Form Campaign; (3) Used Fuel Disposition (UFD) Campaign; and (4) ASCEM.« less

Aeroelastic Optimization of Generalized Tube and Wing Aircraft Concepts Using HCDstruct Version 2.0

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; Gern, Frank H.

2017-01-01

Major enhancements were made to the Higher-fidelity Conceptual Design and structural optimization (HCDstruct) tool developed at NASA Langley Research Center (LaRC). Whereas previous versions were limited to hybrid wing body (HWB) configurations, the current version of HCDstruct now supports the analysis of generalized tube and wing (TW) aircraft concepts. Along with significantly enhanced user input options for all air- craft configurations, these enhancements represent HCDstruct version 2.0. Validation was performed using a Boeing 737-200 aircraft model, for which primary structure weight estimates agreed well with available data. Additionally, preliminary analysis of the NASA D8 (ND8) aircraft concept was performed, highlighting several new features of the tool.

Fidelity study of superconductivity in extended Hubbard models

NASA Astrophysics Data System (ADS)

Plonka, N.; Jia, C. J.; Wang, Y.; Moritz, B.; Devereaux, T. P.

2015-07-01

The Hubbard model with local on-site repulsion is generally thought to possess a superconducting ground state for appropriate parameters, but the effects of more realistic long-range Coulomb interactions have not been studied extensively. We study the influence of these interactions on superconductivity by including nearest- and next-nearest-neighbor extended Hubbard interactions in addition to the usual on-site terms. Utilizing numerical exact diagonalization, we analyze the signatures of superconductivity in the ground states through the fidelity metric of quantum information theory. We find that nearest and next-nearest neighbor interactions have thresholds above which they destabilize superconductivity regardless of whether they are attractive or repulsive, seemingly due to competing charge fluctuations.

Fidelity of Majorana-based quantum operations

NASA Astrophysics Data System (ADS)

Tanhayi Ahari, Mostafa; Ortiz, Gerardo; Seradjeh, Babak

2015-03-01

It is well known that one-dimensional p-wave superconductor, the so-called Kitaev model, has topologically distinct phases that are distinguished by the presence of Majorana fermions. Owing to their topological protection, these Majorana fermions have emerged as candidates for fault-tolerant quantum computation. They furnish the operation of such a computation via processes that produce, braid, and annihilate them in pairs. In this work we study some of these processes from the dynamical perspective. In particular, we determine the fidelity of the Majorana fermions when they are produced or annihilated by tuning the system through the corresponding topological phase transition. For a simple linear protocol, we derive analytical expressions for fidelity and test various perturbative schemes. For more general protocols, we present exact numerics. Our results are relevant for the operation of Majorana-based quantum gates and quantum memories.

Implications of Simulation Conceptual Model Development for Simulation Management and Uncertainty Assessment

NASA Technical Reports Server (NTRS)

Pace, Dale K.

2000-01-01

A simulation conceptual model is a simulation developers way of translating modeling requirements (i. e., what is to be represented by the simulation or its modification) into a detailed design framework (i. e., how it is to be done), from which the software, hardware, networks (in the case of distributed simulation), and systems/equipment that will make up the simulation can be built or modified. A conceptual model is the collection of information which describes a simulation developers concept about the simulation and its pieces. That information consists of assumptions, algorithms, characteristics, relationships, and data. Taken together, these describe how the simulation developer understands what is to be represented by the simulation (entities, actions, tasks, processes, interactions, etc.) and how that representation will satisfy the requirements to which the simulation responds. Thus the conceptual model is the basis for judgment about simulation fidelity and validity for any condition that is not specifically tested. The more perspicuous and precise the conceptual model, the more likely it is that the simulation development will both fully satisfy requirements and allow demonstration that the requirements are satisfied (i. e., validation). Methods used in simulation conceptual model development have significant implications for simulation management and for assessment of simulation uncertainty. This paper suggests how to develop and document a simulation conceptual model so that the simulation fidelity and validity can be most effectively determined. These ideas for conceptual model development apply to all simulation varieties. The paper relates these ideas to uncertainty assessments as they relate to simulation fidelity and validity. The paper also explores implications for simulation management from conceptual model development methods, especially relative to reuse of simulation components.

Transfer of laparoscopic radical prostatectomy skills from bench model to animal model: a prospective, single-blind, randomized, controlled study.

PubMed

Sabbagh, Robert; Chatterjee, Suman; Chawla, Arun; Hoogenes, Jen; Kapoor, Anil; Matsumoto, Edward D

2012-05-01

Learning laparoscopic urethrovesical anastomosis is a crucial step in laparoscopic radical prostatectomy. Previously we noted that practice on a low fidelity urethrovesical model was more effective for trainees than basic suturing drills on a foam pad when learning laparoscopic urethrovesical anastomosis skills. We evaluated learner transfer of skills, specifically whether skills learned on the urethrovesical model would transfer to a high fidelity, live animal model. A total of 28 senior residents, fellows and staff surgeons in urology, general surgery and gynecology were randomized to 2 hours of laparoscopic urethrovesical anastomosis training on a urethrovesical model (group 1) or to basic laparoscopic suturing and knot tying on foam pads (group 2). All participants then performed timed laparoscopic urethrovesical anastomosis on anesthetized female pigs. A blinded urologist scored subject videotaped performance using checklist, global rating scale and end product rating scores. Group 1 was significantly more adept than group 2 at the laparoscopic urethrovesical anastomosis pig task when measured by the checklist, global rating scale and end product rating (each p <0.05). Time to completion was similar in the 2 groups. No statistically significant difference was noted in global rating scale and checklist scores for laparoscopic urethrovesical anastomosis performed on the urethrovesical model vs the pig. Training on a urethrovesical model is superior to training with basic laparoscopic suturing on a foam pad for performing laparoscopic urethrovesical anastomosis skills on an anesthetized female pig. Skills learned on a urethrovesical model transfer to a high fidelity, live animal model. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Estimates of movement and site fidelity using mark-resight data of wintering Canada geese

USGS Publications Warehouse

Hestbeck, J.B.; Nichols, J.D.; Malecki, R.A.

1991-01-01

Population ecologists have devoted disproportionate attention to the estimation and study of birth and death rates and far less effort to rates of movement. Movement and fidelity to wintering areas have important ecological and evolutionary implications for avian populations. Previous inferences about movement among and fidelity to wintering areas have been restricted by limitations of data and methodology. We use multiple observation data from a large-scale capture-resighting study of Canada Geese in the Atlantic flyway to estimate probabilities of returning to previous wintering locations and moving to new locations. Mark-resight data from 28,849 Canada Geese (Branta canadensis) banded woth individually coded neck bands in the mid-Atlantic (New York, Pennsylvania, New Jersey), Chesapeake (Delaware, Maryland, Virginia), and Carolinas (North and South Carolina) were used to estimate movement and site-fidelity. Two three-sample mark-resight models were developed and programmed using SURVIV to estimate the probability of moving among or remaining within these three wintering regions. The model (MV2) that incorporated tradition' or memory of previous wintering regions fit the data better than the model (MV1) that assumes that a first-order Markov chain described movement among regions. Considerable levels of movement occured among regions of the Atlantic flyway. The annual probability of remaining in the same region for two successive winters, used as a measure of site fidelity, was 0.710 plus or minus 0.016 (estimated mean plus or minus SE, 0.889 plus or minus 0.006, and 0.562 plus or minus 0.025, for the mid-Atlantic, Chesapeake, and Carolinas, respectively. The estimated probability of moving between years corresponded to changes in winter harshness. In warm years, geese moved north and in cold years, they moved south. Geese had a high probability of moving to and remaining in the Chesapeake. Annual changes in the movement probabilities did not correspond to annual changes in the United States Fish and Wildlife midwinter survey. Considerable numbers of geese from the Carolinas appeared to be wintering in more northerly locations (short-stopped) in subsequent winters.

Modeling Instruction: The Impact of Professional Development on Instructional Practices

ERIC Educational Resources Information Center

Barlow, Angela T.; Frick, Tasha M.; Barker, Heather L.; Phelps, Amy J.

2014-01-01

Modeling Instruction holds the potential for transforming science instruction and improving student achievement. Key to the success of Modeling Instruction, however, is the fidelity of implementation of its curriculum. This qualitative study examined the impact of Modeling Instruction professional development on participating teachers'…

SSME structural dynamic model development

NASA Technical Reports Server (NTRS)

Foley, M. J.; Tilley, D. M.; Welch, C. T.

1983-01-01

A mathematical model of the Space Shuttle Main Engine (SSME) as a complete assembly, with detailed emphasis on LOX and High Fuel Turbopumps is developed. The advantages of both complete engine dynamics, and high fidelity modeling are incorporated. Development of this model, some results, and projected applications are discussed.

Comparison of simulator fidelity model predictions with in-simulator evaluation data

NASA Technical Reports Server (NTRS)

Parrish, R. V.; Mckissick, B. T.; Ashworth, B. R.

1983-01-01

A full factorial in simulator experiment of a single axis, multiloop, compensatory pitch tracking task is described. The experiment was conducted to provide data to validate extensions to an analytic, closed loop model of a real time digital simulation facility. The results of the experiment encompassing various simulation fidelity factors, such as visual delay, digital integration algorithms, computer iteration rates, control loading bandwidths and proprioceptive cues, and g-seat kinesthetic cues, are compared with predictions obtained from the analytic model incorporating an optimal control model of the human pilot. The in-simulator results demonstrate more sensitivity to the g-seat and to the control loader conditions than were predicted by the model. However, the model predictions are generally upheld, although the predicted magnitudes of the states and of the error terms are sometimes off considerably. Of particular concern is the large sensitivity difference for one control loader condition, as well as the model/in-simulator mismatch in the magnitude of the plant states when the other states match.

Evaluation of Drogue Parachute Damping Effects Utilizing the Apollo Legacy Parachute Model

NASA Technical Reports Server (NTRS)

Currin, Kelly M.; Gamble, Joe D.; Matz, Daniel A.; Bretz, David R.

2011-01-01

Drogue parachute damping is required to dampen the Orion Multi Purpose Crew Vehicle (MPCV) crew module (CM) oscillations prior to deployment of the main parachutes. During the Apollo program, drogue parachute damping was modeled on the premise that the drogue parachute force vector aligns with the resultant velocity of the parachute attach point on the CM. Equivalent Cm(sub q) and Cm(sub alpha) equations for drogue parachute damping resulting from the Apollo legacy parachute damping model premise have recently been developed. The MPCV computer simulations ANTARES and Osiris have implemented high fidelity two-body parachute damping models. However, high-fidelity model-based damping motion predictions do not match the damping observed during wind tunnel and full-scale free-flight oscillatory motion. This paper will present the methodology for comparing and contrasting the Apollo legacy parachute damping model with full-scale free-flight oscillatory motion. The analysis shows an agreement between the Apollo legacy parachute damping model and full-scale free-flight oscillatory motion.

Long-distance entanglement and quantum teleportation in XX spin chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campos Venuti, L.; Giampaolo, S. M.; CNR-INFM Coherentia, Napoli

2007-11-15

Isotropic XX models of one-dimensional spin-1/2 chains are investigated with the aim to elucidate the formal structure and the physical properties that allow these systems to act as channels for long-distance, high-fidelity quantum teleportation. We introduce two types of models: (i) open, dimerized XX chains, and (ii) open XX chains with small end bonds. For both models we obtain the exact expressions for the end-to-end correlations and the scaling of the energy gap with the length of the chain. We determine the end-to-end concurrence and show that model (i) supports true long-distance entanglement at zero temperature, while model (ii) supportsmore » 'quasi-long-distance' entanglement that slowly falls off with the size of the chain. Due to the different scalings of the gaps, respectively exponential for model (i) and algebraic in model (ii), we demonstrate that the latter allows for efficient qubit teleportation with high fidelity in sufficiently long chains even at moderately low temperatures.« less

Towards an Automated Full-Turbofan Engine Numerical Simulation

NASA Technical Reports Server (NTRS)

Reed, John A.; Turner, Mark G.; Norris, Andrew; Veres, Joseph P.

2003-01-01

The objective of this study was to demonstrate the high-fidelity numerical simulation of a modern high-bypass turbofan engine. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled three-dimensional computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady-state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the three-dimensional component models are integrated into the cycle model via partial performance maps generated automatically from the CFD flow solutions using one-dimensional meanline turbomachinery programs. This paper reports on the progress made towards the full-engine simulation of the GE90-94B engine, highlighting the generation of the high-pressure compressor partial performance map. The ongoing work will provide a system to evaluate the steady and unsteady aerodynamic and mechanical interactions between engine components at design and off-design operating conditions.

Response of Honeycomb Core Sandwich Panel with Minimum Gage GFRP Face-Sheets to Compression Loading After Impact

NASA Technical Reports Server (NTRS)

McQuigg, Thomas D.; Kapania, Rakesh K.; Scotti, Stephen J.; Walker, Sandra P.

2011-01-01

A compression after impact study has been conducted to determine the residual strength of three sandwich panel constructions with two types of thin glass fiber reinforced polymer face-sheets and two hexagonal honeycomb Nomex core densities. Impact testing is conducted to first determine the characteristics of damage resulting from various impact energy levels. Two modes of failure are found during compression after impact tests with the density of the core precipitating the failure mode present for a given specimen. A finite element analysis is presented for prediction of the residual compressive strength of the impacted specimens. The analysis includes progressive damage modeling in the face-sheets. Preliminary analysis results were similar to the experimental results; however, a higher fidelity core material model is expected to improve the correlation.

The joint measurement entanglement can significantly offset the effect of a noisy channel in teleportation

NASA Astrophysics Data System (ADS)

Roa, Luis; Ladrón de Guevara, María L.; Soto-Moscoso, Matias; Catalán, Pamela

2018-05-01

In our work we consider the following problem in the context of teleportation: an unknown pure state has to be teleported and there are two laboratories which can perform the task. One laboratory uses a pure non-maximally entangled channel but has a capability of performing the joint measurement on bases with a constrained degree of entanglement; the other lab makes use of a mixed X-state channel but can perform a joint measurement on bases with higher entanglement degrees. We compare the average teleportation fidelity achieved in both cases, finding that the fidelity achieved with the X-state can surpass the obtained with a pure channel, even though the X-state is less entangled than the latter. We find the conditions under which this effect occurs. Our results evidence that the entanglement of the joint measurement plays a role as important as the entanglement of the channel in order to optimize the teleportation process. We include an example showing that the average fidelity of teleportation obtained with a Werner state channel can be greater than that obtained with a Bell state channel.

Fidelity of northern pine snakes (Pituophis m. melanoleucus) to natural and artificial hibernation sites in the New Jersey Pine Barrens.

PubMed

Zappalorti, Robert T; Burger, Joanna; Burkett, David W; Schneider, David W; McCort, Matthew P; Golden, David M

2014-01-01

Environmental managers require information on whether human-made hibernacula are used by rare snakes before constructing large numbers of them as mitigation measures. Fidelity of northern pine snakes (Pituophis m. melanoleucus) was examined in a 6-year study in the New Jersey Pine Barrens to determine whether they used natural and artificial hibernacula equally. Pine snakes used both artificial (human-made) and natural (snake-adapted) hibernacula. Most natural hibernacula were in abandoned burrows of large mammals. Occupancy rates were similar between natural and artificial hibernacula. Only 6 of 27 radio-tracked snakes did not shift hibernacula between years, whereas 78% shifted sites at least once, and fidelity from one year to the next was 42%. For snakes that switched hibernacula (n = 21), one switched among artificial hibernacula, 14 (65%) switched among natural hibernacula, and 6 (29%) switched from artificial to natural hibernacula. Data indicate that most pine snakes switch among hibernacula, mainly selecting natural hibernacula, suggesting that artificial dens are used, but protecting natural hibernacula should be a higher conservation priority.

Hinge residue I174 is critical for proper dNTP selection by DNA polymerase beta.

PubMed

Yamtich, Jen; Starcevic, Daniela; Lauper, Julia; Smith, Elenoe; Shi, Idina; Rangarajan, Sneha; Jaeger, Joachim; Sweasy, Joann B

2010-03-23

DNA polymerase beta (pol beta) is the key gap-filling polymerase in base excision repair, the DNA repair pathway responsible for repairing up to 20000 endogenous lesions per cell per day. Pol beta is also widely used as a model polymerase for structure and function studies, and several structural regions have been identified as being critical for the fidelity of the enzyme. One of these regions is the hydrophobic hinge, a network of hydrophobic residues located between the palm and fingers subdomains. Previous work by our lab has shown that hinge residues Y265, I260, and F272 are critical for polymerase fidelity by functioning in discrimination of the correct from incorrect dNTP during ground state binding. Our work aimed to elucidate the role of hinge residue I174 in polymerase fidelity. To study this residue, we conducted a genetic screen to identify mutants with a substitution at residue I174 that resulted in a mutator polymerase. We then chose the mutator mutant I174S for further study and found that it follows the same general kinetic pathway as and has an overall protein folding similar to that of wild-type (WT) pol beta. Using single-turnover kinetic analysis, we found that I174S exhibits decreased fidelity when inserting a nucleotide opposite a template base G, and this loss of fidelity is due primarily to a loss of discrimination during ground state dNTP binding. Molecular dynamics simulations show that mutation of residue I174 to serine results in an overall tightening of the hinge region, resulting in aberrant protein dynamics and fidelity. These results point to the hinge region as being critical in the maintenance of the proper geometry of the dNTP binding pocket.

Paper prototypes for the detection of stereotype violations in (medical) device operation - are they good enough?

PubMed

Hallbeck, M Susan; Koneczny, Sonja; Smith, Justine

2009-01-01

Controls for most technologies, including medical devices, are becoming increasingly complex, difficult to intuitively understand and don't necessarily follow population stereotypes. The resulting delays and errors are unacceptable when seconds can mean the difference between life and death. In this study participants were asked to "control" a system using a paper prototype (color photographs of controls) and then with a higher fidelity prototype of the same physical controls to determine performance differences among ethnicities and genders. No ethnic nor gender differences were found, and the comparison of paper versus higher fidelity prototypes also showed no significant differences. Thus, paper prototypes can be employed as an early device design usability tool to illustrate stereotype violations long before the first physical prototype. This will not only save money in the development and design processes, but also makes sure that even the most complex devices are intuitively understandable and operable for their basic functions.

Exploiting current-generation graphics hardware for synthetic-scene generation

NASA Astrophysics Data System (ADS)

Tanner, Michael A.; Keen, Wayne A.

2010-04-01

Increasing seeker frame rate and pixel count, as well as the demand for higher levels of scene fidelity, have driven scene generation software for hardware-in-the-loop (HWIL) and software-in-the-loop (SWIL) testing to higher levels of parallelization. Because modern PC graphics cards provide multiple computational cores (240 shader cores for a current NVIDIA Corporation GeForce and Quadro cards), implementation of phenomenology codes on graphics processing units (GPUs) offers significant potential for simultaneous enhancement of simulation frame rate and fidelity. To take advantage of this potential requires algorithm implementation that is structured to minimize data transfers between the central processing unit (CPU) and the GPU. In this paper, preliminary methodologies developed at the Kinetic Hardware In-The-Loop Simulator (KHILS) will be presented. Included in this paper will be various language tradeoffs between conventional shader programming, Compute Unified Device Architecture (CUDA) and Open Computing Language (OpenCL), including performance trades and possible pathways for future tool development.

Relationship Between Implementation of Collaborative Strategic Reading and Student Outcomes for Adolescents With Disabilities.

PubMed

Boardman, Alison G; Buckley, Pamela; Vaughn, Sharon; Roberts, Gregory; Scornavacco, Karla; Klingner, Janette K

2016-11-01

This study examines the interaction between the fidelity of implementation of a set of research-based strategies-Collaborative Strategic Reading (CSR)-and outcomes for students with mild to moderate disabilities using data from two nonoverlapping studies in middle school language arts and reading classrooms (Study 1) and middle school social studies and science classrooms (Study 2). The authors use a definition of fidelity that includes both the amount of CSR instruction delivered by teachers and the quality of implementation. Although there were no main effects for quality or amount of CSR instruction, in both studies there was an interaction effect between quality of implementation and special education status. The study used a within-groups design and multilevel analyses, and the results demonstrate that higher quality CSR instruction was associated with higher reading outcomes for students with disabilities. This finding was consistent across Study 1 and Study 2. Implications for practice and future research are discussed. © Hammill Institute on Disabilities 2016.

Chromium reduces the in vitro activity and fidelity of DNA replication mediated by the human cell DNA synthesome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai Heqiao; Liu Jianying; Malkas, Linda H.

2009-04-15

Hexavalent chromium Cr(VI) is known to be a carcinogenic metal ion, with a complicated mechanism of action. It can be found within our environment in soil and water contaminated by manufacturing processes. Cr(VI) ion is readily taken up by cells, and is recognized to be both genotoxic and cytotoxic; following its reduction to the stable trivalent form of the ion, chromium(Cr(III)), within cells. This form of the ion is known to impede the activity of cellular DNA polymerase and polymerase-mediated DNA replication. Here, we report the effects of chromium on the activity and fidelity of the DNA replication process mediatedmore » by the human cell DNA synthesome. The DNA synthesome is a functional multiprotein complex that is fully competent to carry-out each phase of the DNA replication process. The IC{sub 50} of Cr(III) toward the activity of DNA synthesome-associated DNA polymerases {alpha}, {delta} and {epsilon} is 15, 45 and 125 {mu}M, respectively. Cr(III) inhibits synthesome-mediated DNA synthesis (IC{sub 50} = 88 {mu}M), and significantly reduces the fidelity of synthesome-mediated DNA replication. The mutation frequency induced by the different concentrations of Cr(III) ion used in our assays ranges from 2-13 fold higher than that which occurs spontaneously, and the types of mutations include single nucleotide substitutions, insertions, and deletions. Single nucleotide substitutions are the predominant type of mutation, and they occur primarily at GC base-pairs. Cr(III) ion produces a lower number of transition and a higher number of transversion mutations than occur spontaneously. Unlike Cr(III), Cr(VI) ion has little effect on the in vitro DNA synthetic activity and fidelity of the DNA synthesome, but does significantly inhibit DNA synthesis in intact cells. Cell growth and proliferation is also arrested by increasing concentrations of Cr(VI) ion. Our studies provide evidence indicating that the chromium ion induced decrease in the fidelity and activity of synthesome mediated DNA replication correlates with the genotoxic and cytotoxic effects of this metal ion; and promotes cell killing via inhibition of the DNA polymerase activity mediating the DNA replication and repair processes utilized by human cells.« less

Chromium reduces the in vitro activity and fidelity of DNA replication mediated by the human cell DNA synthesome

PubMed Central

Dai, Heqiao; Liu, Jianying; Malkas, Linda H.; Catalano, Jennifer; Alagharu, Srilakshmi; Hickey, Robert J.

2009-01-01

Hexavalent chromium Cr(VI) is known to be a carcinogenic metal ion, with a complicated mechanism of action. It can be found within our environment in soil and water contaminated by manufacturing processes. Cr(VI) ion is readily taken up by cells, and is recognized to be both genotoxic and cytotoxic; following its reduction to the stable trivalent form of the ion, chromium(Cr(III)), within cells. This form of the ion is known to impede the activity of cellular DNA polymerase and polymerase-mediated DNA replication. Here, we report the effects of chromium on the activity and fidelity of the DNA replication process mediated by the human cell DNA synthesome. The DNA synthesome is a functional multiprotein complex that is fully competent to carry-out each phase of the DNA replication process. The IC50 of Cr(III) toward the activity of DNA synthesome-associated DNA polymerases α, δ and ε is 15, 45 and 125 μM, respectively. Cr(III) inhibits synthesome-mediated DNA synthesis (IC50 =88 μM), and significantly reduces the fidelity of synthesome-mediated DNA replication. The mutation frequency induced by the different concentrations of Cr(III) ion used in our assays ranges from 2–13 fold higher than that which occurs spontaneously, and the types of mutations include single nucleotide substitutions, insertions, and deletions. Single nucleotide substitutions are the predominant type of mutation, and they occur primarily at GC base-pairs. Cr(III) ion produces a lower number of transition and a higher number of transversion mutations than occur spontaneously. Unlike Cr (III), Cr(VI) ion has little effect on the in vitro DNA synthetic activity and fidelity of the DNA synthesome, but does significantly inhibit DNA synthesis in intact cells. Cell growth and proliferation is also arrested by increasing concentrations of Cr(VI) ion. Our studies provide evidence indicating that the chromium ion induced decrease in the fidelity and activity of synthesome mediated DNA replication correlates with the genotoxic and cytotoxic effects of this metal ion; and promotes cell killing via inhibition of the DNA polymerase activity mediating the DNA replication and repair processes utilized by human cells. PMID:19371627

Kinetic measurement of 2-aminopurine X cytosine and 2-aminopurine X thymine base pairs as a test of DNA polymerase fidelity mechanisms.

PubMed Central

Watanabe, S M; Goodman, M F

1982-01-01

Enzyme kinetic measurements are presented showing that Km rather than maximum velocity (Vmax) discrimination governs the frequency of forming 2-aminopurine X cytosine base mispairs by DNA polymerase alpha. An in vitro system is used in which incorporation of dTMP or dCMP occurs opposite a template 2-aminopurine, and values for Km and Vmax are obtained. Results from a previous study in which dTTP and dCTP were competing simultaneously for insertion opposite 2-aminopurine indicated that dTMP is inserted 22 times more frequently than dCMP. We now report that the ratio of Km values KCm/KTm = 25 +/- 6, which agrees quantitatively with the dTMP/dCMP incorporation ratio obtained previously. We also report that VCmax is indistinguishable from VTmax. These Km and Vmax data are consistent with predictions from a model, the Km discrimination model, in which replication fidelity is determined by free energy differences between matched and mismatched base pairs. Central to this model is the prediction that the ratio of Km values for insertion of correct and incorrect nucleotides specifies the insertion fidelity, and the maximum velocities of insertion are the same for both nucleotides. PMID:6959128

The use of high fidelity CAD models as the basis for training on complex systems

NASA Technical Reports Server (NTRS)

Miller, Kellie; Tanner, Steve

1993-01-01

During the design phases of large and complex systems such as NASA's Space Station Freedom (SSF), there are few, if any physical prototypes built. This is often due to their expense and the realization that the design is likely to change. This poses a problem for training, maintainability, and operations groups who are tasked to lay the foundation of plans for using these systems. The Virtual Reality and Visualization Laboratory at the Boeing Advanced Computing Group's Huntsville facility is supporting the use of high fidelity, detailed design models that are generated during the initial design phases, for use in training, maintainability and operations exercises. This capability was used in its non-immersive form to great effect at the SSF Critical Design Review (CDR) during February, 1993. Allowing the user to move about within a CAD design supports many efforts, including training and scenario study. We will demonstrate via a video of the Maintainability SSF CDR how this type of approach can be used and why it is so effective in conveying large amounts of information quickly and concisely. We will also demonstrate why high fidelity models are so important for this type of training system and how it's immersive aspects may be exploited as well.

Slot-like capacity and resource-like coding in a neural model of multiple-item working memory.

PubMed

Standage, Dominic; Pare, Martin

2018-06-27

For the past decade, research on the storage limitations of working memory has been dominated by two fundamentally different hypotheses. On the one hand, the contents of working memory may be stored in a limited number of `slots', each with a fixed resolution. On the other hand, any number of items may be stored, but with decreasing resolution. These two hypotheses have been invaluable in characterizing the computational structure of working memory, but neither provides a complete account of the available experimental data, nor speaks to the neural basis of the limitations it characterizes. To address these shortcomings, we simulated a multiple-item working memory task with a cortical network model, the cellular resolution of which allowed us to quantify the coding fidelity of memoranda as a function of memory load, as measured by the discriminability, regularity and reliability of simulated neural spiking. Our simulations account for a wealth of neural and behavioural data from human and non-human primate studies, and they demonstrate that feedback inhibition lowers both capacity and coding fidelity. Because the strength of inhibition scales with the number of items stored by the network, increasing this number progressively lowers fidelity until capacity is reached. Crucially, the model makes specific, testable predictions for neural activity on multiple-item working memory tasks.

Lapses, infidelities, and creative adaptations: lessons from evaluation of a participatory market development approach in the Andes.

PubMed

Horton, Douglas; Rotondo, Emma; Paz Ybarnegaray, Rodrigo; Hareau, Guy; Devaux, André; Thiele, Graham

2013-08-01

Participatory approaches are frequently recommended for international development programs, but few have been evaluated. From 2007 to 2010 the Andean Change Alliance evaluated an agricultural research and development approach known as the "Participatory Market Chain Approach" (PMCA). Based on a study of four cases, this paper examines the fidelity of implementation, the factors that influenced implementation and results, and the PMCA change model. We identify three types of deviation from the intervention protocol (lapses, creative adaptations, and true infidelities) and five groups of variables that influenced PMCA implementation and results (attributes of the macro context, the market chain, the key actors, rules in use, and the capacity development strategy). There was insufficient information to test the validity of the PMCA change model, but results were greatest where the PMCA was implemented with highest fidelity. Our analysis suggests that the single most critical component of the PMCA is engagement of market agents - not just farmers - throughout the exercise. We present four lessons for planning and evaluating participatory approaches related to the use of action and change models, the importance of monitoring implementation fidelity, the limits of baseline survey data for outcome evaluation, and the importance of capacity development for implementers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Seasonality of Precipitation over Himalayan Watersheds in CORDEX South Asia and their Driving CMIP5 Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

ul Hasson, Shabeh

Since the Coupled Model Intercomparison Project Phase 5 (CMIP5) experiments exhibit limited skill in reproducing the statistical properties of prevailing precipitation regimes over the major Himalayan watersheds (Indus, Ganges, Brahmaputra and Mekong), this study evaluates the anticipated added skill of their dynamically refined simulations performed under the framework of Coordinated Regional Climate Downscaling Experiments for South Asia (CX-SA). For this, the fidelity of eight CX-SA experiments against their six driving CMIP5 experiments is assessed for the historical period (1971–2005) in terms of time-dependent statistical properties (onset/retreat timings and rapid fractional accumulation—RFA) of the dominant summer monsoonal precipitation regime (MPR). Further,more » a self-defining seasonality index (SI), which is a product of precipitation and the distance of its actual distribution relative to its uniform distribution (relative entropy—RE), has been computed for MPR, westerly precipitation regime (WPR) and annual precipitation. The time evolution of precipitation, RE and SI has also been analyzed. Results suggest that CX-SA experiments simulate even higher wet biases than their driving CMIP5 experiments over all study basins, mainly due to higher wet biases simulated over the Himalayas and Tibetan Plateau. Most of the CX-SA experiments suggest unrealistic timings of the monsoon onset that are far earlier than their driving CMIP5 experiments for all basins. Generally, CX-SA experiments feature higher underestimation of RFA slope, RE and SI, distancing their driving CMIP5 experiments farther from observations. Interestingly, regardless of the diverse skill of CMIP5 experiments, their fine scale CX-SA experiments exhibit quite a similar skill when downscaled by the same regional climate model (RCM), indicating RCM’s ability to considerably alter the driving datasets. Lastly, these findings emphasize on improving the fidelity of simulated precipitation regimes over the Himalayan watersheds by exploiting the potential of RCMs in term of microphysics, resolutions and convective closures, and preferably, on resolving the crucial fine scale processes further down to their representative (meso-to-local) scales.« less

Seasonality of Precipitation over Himalayan Watersheds in CORDEX South Asia and their Driving CMIP5 Experiments

DOE PAGES

ul Hasson, Shabeh

2016-10-02

Since the Coupled Model Intercomparison Project Phase 5 (CMIP5) experiments exhibit limited skill in reproducing the statistical properties of prevailing precipitation regimes over the major Himalayan watersheds (Indus, Ganges, Brahmaputra and Mekong), this study evaluates the anticipated added skill of their dynamically refined simulations performed under the framework of Coordinated Regional Climate Downscaling Experiments for South Asia (CX-SA). For this, the fidelity of eight CX-SA experiments against their six driving CMIP5 experiments is assessed for the historical period (1971–2005) in terms of time-dependent statistical properties (onset/retreat timings and rapid fractional accumulation—RFA) of the dominant summer monsoonal precipitation regime (MPR). Further,more » a self-defining seasonality index (SI), which is a product of precipitation and the distance of its actual distribution relative to its uniform distribution (relative entropy—RE), has been computed for MPR, westerly precipitation regime (WPR) and annual precipitation. The time evolution of precipitation, RE and SI has also been analyzed. Results suggest that CX-SA experiments simulate even higher wet biases than their driving CMIP5 experiments over all study basins, mainly due to higher wet biases simulated over the Himalayas and Tibetan Plateau. Most of the CX-SA experiments suggest unrealistic timings of the monsoon onset that are far earlier than their driving CMIP5 experiments for all basins. Generally, CX-SA experiments feature higher underestimation of RFA slope, RE and SI, distancing their driving CMIP5 experiments farther from observations. Interestingly, regardless of the diverse skill of CMIP5 experiments, their fine scale CX-SA experiments exhibit quite a similar skill when downscaled by the same regional climate model (RCM), indicating RCM’s ability to considerably alter the driving datasets. Lastly, these findings emphasize on improving the fidelity of simulated precipitation regimes over the Himalayan watersheds by exploiting the potential of RCMs in term of microphysics, resolutions and convective closures, and preferably, on resolving the crucial fine scale processes further down to their representative (meso-to-local) scales.« less

What Was Learned in Predicting Slender Airframe Aerodynamics with the F-16XL Aircraft

NASA Technical Reports Server (NTRS)

Rizzi, Arthur; Luckring, James M.

2016-01-01

The second Cranked-Arrow Wing Aerodynamics Project, International, coordinated project has been underway to improve high-fidelity computational-fluid-dynamics predictions of slender airframe aerodynamics. The work is focused on two flow conditions and leverages a unique flight data set obtained with the F-16XL aircraft for comparison and validation. These conditions, a low-speed high-angle-of-attack case and a transonic low-angle-of-attack case, were selected from a prior prediction campaign wherein the computational fluid dynamics failed to provide acceptable results. In revisiting these two cases, approaches for improved results include better, denser grids using more grid adaptation to local flow features as well as unsteady higher-fidelity physical modeling like hybrid Reynolds-averaged Navier-Stokes/unsteady Reynolds-averaged Navier-Stokes/large-eddy simulation methods. The work embodies predictions from multiple numerical formulations that are contributed from multiple organizations where some authors investigate other possible factors that could explain the discrepancies in agreement (e.g., effects due to deflected control surfaces during the flight tests as well as static aeroelastic deflection of the outer wing). This paper presents the synthesis of all the results and findings and draws some conclusions that lead to an improved understanding of the underlying flow physics, finally making the connections between the physics and aircraft features.

Progress Toward Affordable High Fidelity Combustion Simulations Using Filtered Density Functions for Hypersonic Flows in Complex Geometries

NASA Technical Reports Server (NTRS)

Drozda, Tomasz G.; Quinlan, Jesse R.; Pisciuneri, Patrick H.; Yilmaz, S. Levent

2012-01-01

Significant progress has been made in the development of subgrid scale (SGS) closures based on a filtered density function (FDF) for large eddy simulations (LES) of turbulent reacting flows. The FDF is the counterpart of the probability density function (PDF) method, which has proven effective in Reynolds averaged simulations (RAS). However, while systematic progress is being made advancing the FDF models for relatively simple flows and lab-scale flames, the application of these methods in complex geometries and high speed, wall-bounded flows with shocks remains a challenge. The key difficulties are the significant computational cost associated with solving the FDF transport equation and numerically stiff finite rate chemistry. For LES/FDF methods to make a more significant impact in practical applications a pragmatic approach must be taken that significantly reduces the computational cost while maintaining high modeling fidelity. An example of one such ongoing effort is at the NASA Langley Research Center, where the first generation FDF models, namely the scalar filtered mass density function (SFMDF) are being implemented into VULCAN, a production-quality RAS and LES solver widely used for design of high speed propulsion flowpaths. This effort leverages internal and external collaborations to reduce the overall computational cost of high fidelity simulations in VULCAN by: implementing high order methods that allow reduction in the total number of computational cells without loss in accuracy; implementing first generation of high fidelity scalar PDF/FDF models applicable to high-speed compressible flows; coupling RAS/PDF and LES/FDF into a hybrid framework to efficiently and accurately model the effects of combustion in the vicinity of the walls; developing efficient Lagrangian particle tracking algorithms to support robust solutions of the FDF equations for high speed flows; and utilizing finite rate chemistry parametrization, such as flamelet models, to reduce the number of transported reactive species and remove numerical stiffness. This paper briefly introduces the SFMDF model (highlighting key benefits and challenges), and discusses particle tracking for flows with shocks, the hybrid coupled RAS/PDF and LES/FDF model, flamelet generated manifolds (FGM) model, and the Irregularly Portioned Lagrangian Monte Carlo Finite Difference (IPLMCFD) methodology for scalable simulation of high-speed reacting compressible flows.

Medium Fidelity Simulation of Oxygen Tank Venting

NASA Technical Reports Server (NTRS)

Sweet, Adam; Kurien, James; Lau, Sonie (Technical Monitor)

2001-01-01

The item to he cleared is a medium-fidelity software simulation model of a vented cryogenic tank. Such tanks are commonly used to transport cryogenic liquids such as liquid oxygen via truck, and have appeared on liquid-fueled rockets for decades. This simulation model works with the HCC simulation system that was developed by Xerox PARC and NASA Ames Research Center. HCC has been previously cleared for distribution. When used with the HCC software, the model generates simulated readings for the tank pressure and temperature as the simulated cryogenic liquid boils off and is vented. Failures (such as a broken vent valve) can be injected into the simulation to produce readings corresponding to the failure. Release of this simulation will allow researchers to test their software diagnosis systems by attempting to diagnose the simulated failure from the simulated readings. This model does not contain any encryption software nor can it perform any control tasks that might be export controlled.

Surrogate Modeling of High-Fidelity Fracture Simulations for Real-Time Residual Strength Predictions

NASA Technical Reports Server (NTRS)

Spear, Ashley D.; Priest, Amanda R.; Veilleux, Michael G.; Ingraffea, Anthony R.; Hochhalter, Jacob D.

2011-01-01

A surrogate model methodology is described for predicting in real time the residual strength of flight structures with discrete-source damage. Starting with design of experiment, an artificial neural network is developed that takes as input discrete-source damage parameters and outputs a prediction of the structural residual strength. Target residual strength values used to train the artificial neural network are derived from 3D finite element-based fracture simulations. A residual strength test of a metallic, integrally-stiffened panel is simulated to show that crack growth and residual strength are determined more accurately in discrete-source damage cases by using an elastic-plastic fracture framework rather than a linear-elastic fracture mechanics-based method. Improving accuracy of the residual strength training data would, in turn, improve accuracy of the surrogate model. When combined, the surrogate model methodology and high-fidelity fracture simulation framework provide useful tools for adaptive flight technology.