Gauging Metallicity of Diffuse Gas under an Uncertain Ionizing Radiation Field

NASA Astrophysics Data System (ADS)

Chen, Hsiao-Wen; Johnson, Sean D.; Zahedy, Fakhri S.; Rauch, Michael; Mulchaey, John S.

2017-06-01

Gas metallicity is a key quantity used to determine the physical conditions of gaseous clouds in a wide range of astronomical environments, including interstellar and intergalactic space. In particular, considerable effort in circumgalactic medium (CGM) studies focuses on metallicity measurements because gas metallicity serves as a critical discriminator for whether the observed heavy ions in the CGM originate in chemically enriched outflows or in more chemically pristine gas accreted from the intergalactic medium. However, because the gas is ionized, a necessary first step in determining CGM metallicity is to constrain the ionization state of the gas which, in addition to gas density, depends on the ultraviolet background radiation field (UVB). While it is generally acknowledged that both the intensity and spectral slope of the UVB are uncertain, the impact of an uncertain spectral slope has not been properly addressed in the literature. This Letter shows that adopting a different spectral slope can result in an order of magnitude difference in the inferred CGM metallicity. Specifically, a harder UVB spectrum leads to a higher estimated gas metallicity for a given set of observed ionic column densities. Therefore, such systematic uncertainties must be folded into the error budget for metallicity estimates of ionized gas. An initial study shows that empirical diagnostics are available for discriminating between hard and soft ionizing spectra. Applying these diagnostics helps reduce the systematic uncertainties in CGM metallicity estimates.

Gauging Metallicity of Diffuse Gas under an Uncertain Ionizing Radiation Field

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

Chen, Hsiao-Wen; Zahedy, Fakhri S.; Johnson, Sean D.

Gas metallicity is a key quantity used to determine the physical conditions of gaseous clouds in a wide range of astronomical environments, including interstellar and intergalactic space. In particular, considerable effort in circumgalactic medium (CGM) studies focuses on metallicity measurements because gas metallicity serves as a critical discriminator for whether the observed heavy ions in the CGM originate in chemically enriched outflows or in more chemically pristine gas accreted from the intergalactic medium. However, because the gas is ionized, a necessary first step in determining CGM metallicity is to constrain the ionization state of the gas which, in addition tomore » gas density, depends on the ultraviolet background radiation field (UVB). While it is generally acknowledged that both the intensity and spectral slope of the UVB are uncertain, the impact of an uncertain spectral slope has not been properly addressed in the literature. This Letter shows that adopting a different spectral slope can result in an order of magnitude difference in the inferred CGM metallicity. Specifically, a harder UVB spectrum leads to a higher estimated gas metallicity for a given set of observed ionic column densities. Therefore, such systematic uncertainties must be folded into the error budget for metallicity estimates of ionized gas. An initial study shows that empirical diagnostics are available for discriminating between hard and soft ionizing spectra. Applying these diagnostics helps reduce the systematic uncertainties in CGM metallicity estimates.« less

Estimation in Linear Systems Featuring Correlated Uncertain Observations Coming from Multiple Sensors

NASA Astrophysics Data System (ADS)

Caballero-Águila, R.; Hermoso-Carazo, A.; Linares-Pérez, J.

2009-08-01

In this paper, the state least-squares linear estimation problem from correlated uncertain observations coming from multiple sensors is addressed. It is assumed that, at each sensor, the state is measured in the presence of additive white noise and that the uncertainty in the observations is characterized by a set of Bernoulli random variables which are only correlated at consecutive time instants. Assuming that the statistical properties of such variables are not necessarily the same for all the sensors, a recursive filtering algorithm is proposed, and the performance of the estimators is illustrated by a numerical simulation example wherein a signal is estimated from correlated uncertain observations coming from two sensors with different uncertainty characteristics.

Estimating the Uncertain Mathematical Structure of Hydrological Model via Bayesian Data Assimilation

NASA Astrophysics Data System (ADS)

Bulygina, N.; Gupta, H.; O'Donell, G.; Wheater, H.

2008-12-01

The structure of hydrological model at macro scale (e.g. watershed) is inherently uncertain due to many factors, including the lack of a robust hydrological theory at the macro scale. In this work, we assume that a suitable conceptual model for the hydrologic system has already been determined - i.e., the system boundaries have been specified, the important state variables and input and output fluxes to be included have been selected, and the major hydrological processes and geometries of their interconnections have been identified. The structural identification problem then is to specify the mathematical form of the relationships between the inputs, state variables and outputs, so that a computational model can be constructed for making simulations and/or predictions of system input-state-output behaviour. We show how Bayesian data assimilation can be used to merge both prior beliefs in the form of pre-assumed model equations with information derived from the data to construct a posterior model. The approach, entitled Bayesian Estimation of Structure (BESt), is used to estimate a hydrological model for a small basin in England, at hourly time scales, conditioned on the assumption of 3-dimensional state - soil moisture storage, fast and slow flow stores - conceptual model structure. Inputs to the system are precipitation and potential evapotranspiration, and outputs are actual evapotranspiration and streamflow discharge. Results show the difference between prior and posterior mathematical structures, as well as provide prediction confidence intervals that reflect three types of uncertainty: due to initial conditions, due to input and due to mathematical structure.

Estimation of Community Land Model parameters for an improved assessment of net carbon fluxes at European sites

NASA Astrophysics Data System (ADS)

Post, Hanna; Vrugt, Jasper A.; Fox, Andrew; Vereecken, Harry; Hendricks Franssen, Harrie-Jan

2017-03-01

The Community Land Model (CLM) contains many parameters whose values are uncertain and thus require careful estimation for model application at individual sites. Here we used Bayesian inference with the DiffeRential Evolution Adaptive Metropolis (DREAM(zs)) algorithm to estimate eight CLM v.4.5 ecosystem parameters using 1 year records of half-hourly net ecosystem CO2 exchange (NEE) observations of four central European sites with different plant functional types (PFTs). The posterior CLM parameter distributions of each site were estimated per individual season and on a yearly basis. These estimates were then evaluated using NEE data from an independent evaluation period and data from "nearby" FLUXNET sites at 600 km distance to the original sites. Latent variables (multipliers) were used to treat explicitly uncertainty in the initial carbon-nitrogen pools. The posterior parameter estimates were superior to their default values in their ability to track and explain the measured NEE data of each site. The seasonal parameter values reduced with more than 50% (averaged over all sites) the bias in the simulated NEE values. The most consistent performance of CLM during the evaluation period was found for the posterior parameter values of the forest PFTs, and contrary to the C3-grass and C3-crop sites, the latent variables of the initial pools further enhanced the quality-of-fit. The carbon sink function of the forest PFTs significantly increased with the posterior parameter estimates. We thus conclude that land surface model predictions of carbon stocks and fluxes require careful consideration of uncertain ecological parameters and initial states.

Prediction-based control for LTI systems with uncertain time-varying delays and partial state knowledge

NASA Astrophysics Data System (ADS)

Léchappé, V.; Moulay, E.; Plestan, F.

2018-06-01

The stability of a prediction-based controller for linear time-invariant (LTI) systems is studied in the presence of time-varying input and output delays. The uncertain delay case is treated as well as the partial state knowledge case. The reduction method is used in order to prove the convergence of the closed-loop system including the state observer, the predictor and the plant. Explicit conditions that guarantee the closed-loop stability are given, thanks to a Lyapunov-Razumikhin analysis. Simulations illustrate the theoretical results.

Investigation of resonances in 20Mg: Implications for astrophysics and nuclear forces

NASA Astrophysics Data System (ADS)

Randhawa, Jaspreet; Kanungo, Rituparna; Alcorta, Martin; Burbadge, Christina; Burke, Devin; Christian, Greg; Davids, Barry; Even, Julia; Hackman, Greg; Henderson, Jack; Ishimoto, Shigeru; Kaur, Satbir; Keefe, Matthew; Kruecken, Reiner; Lighthall, Jon; Moukaddam, Mohamad; Padilla-Rodal, Elizabeth; Smith, Jenna; Turko, Joseph; Workman, Orry

2016-09-01

18Ne(2p, γ)20Mg provides a possible pathway for breakout from the hot CNO cycles to the rp-process in type I X-ray bursts. This reaction rate is uncertain due to lack of any experimental information on the resonant states in 20Mg above proton emission threshold. Recent calculations using nuclear forces from chiral perturbation theory predict quite a different level structure for 20Mg with and without inclusion of three nucleon forces. These differences make study of 20Mg states important to constraint both nuclear theory and this reaction rate. We have investigated the excited states in 20Mg through inelastic deuteron scattering. The experiment was performed using the IRIS facility at TRIUMF, Canada. The 20Mg beam with an average intensity of 500 pps and energy of 8.5A MeV was directed at novel thin windowless solid deuteron target. Experiment and initial observations will be discussed.

Fuzzy Adaptive Output Feedback Control of Uncertain Nonlinear Systems With Prescribed Performance.

PubMed

Zhang, Jin-Xi; Yang, Guang-Hong

2018-05-01

This paper investigates the tracking control problem for a family of strict-feedback systems in the presence of unknown nonlinearities and immeasurable system states. A low-complexity adaptive fuzzy output feedback control scheme is proposed, based on a backstepping method. In the control design, a fuzzy adaptive state observer is first employed to estimate the unmeasured states. Then, a novel error transformation approach together with a new modification mechanism is introduced to guarantee the finite-time convergence of the output error to a predefined region and ensure the closed-loop stability. Compared with the existing methods, the main advantages of our approach are that: 1) without using extra command filters or auxiliary dynamic surface control techniques, the problem of explosion of complexity can still be addressed and 2) the design procedures are independent of the initial conditions. Finally, two practical examples are performed to further illustrate the above theoretic findings.

Synchronization between uncertain nonidentical networks with quantum chaotic behavior

NASA Astrophysics Data System (ADS)

Li, Wenlin; Li, Chong; Song, Heshan

2016-11-01

Synchronization between uncertain nonidentical networks with quantum chaotic behavior is researched. The identification laws of unknown parameters in state equations of network nodes, the adaptive laws of configuration matrix elements and outer coupling strengths are determined based on Lyapunov theorem. The conditions of realizing synchronization between uncertain nonidentical networks are discussed and obtained. Further, Jaynes-Cummings model in physics are taken as the nodes of two networks and simulation results show that the synchronization performance between networks is very stable.

Combined Uncertainty and A-Posteriori Error Bound Estimates for CFD Calculations: Theory and Implementation

NASA Technical Reports Server (NTRS)

Barth, Timothy J.

2014-01-01

Simulation codes often utilize finite-dimensional approximation resulting in numerical error. Some examples include, numerical methods utilizing grids and finite-dimensional basis functions, particle methods using a finite number of particles. These same simulation codes also often contain sources of uncertainty, for example, uncertain parameters and fields associated with the imposition of initial and boundary data,uncertain physical model parameters such as chemical reaction rates, mixture model parameters, material property parameters, etc.

Rational selection of experimental readout and intervention sites for reducing uncertainties in computational model predictions.

PubMed

Flassig, Robert J; Migal, Iryna; der Zalm, Esther van; Rihko-Struckmann, Liisa; Sundmacher, Kai

2015-01-16

Understanding the dynamics of biological processes can substantially be supported by computational models in the form of nonlinear ordinary differential equations (ODE). Typically, this model class contains many unknown parameters, which are estimated from inadequate and noisy data. Depending on the ODE structure, predictions based on unmeasured states and associated parameters are highly uncertain, even undetermined. For given data, profile likelihood analysis has been proven to be one of the most practically relevant approaches for analyzing the identifiability of an ODE structure, and thus model predictions. In case of highly uncertain or non-identifiable parameters, rational experimental design based on various approaches has shown to significantly reduce parameter uncertainties with minimal amount of effort. In this work we illustrate how to use profile likelihood samples for quantifying the individual contribution of parameter uncertainty to prediction uncertainty. For the uncertainty quantification we introduce the profile likelihood sensitivity (PLS) index. Additionally, for the case of several uncertain parameters, we introduce the PLS entropy to quantify individual contributions to the overall prediction uncertainty. We show how to use these two criteria as an experimental design objective for selecting new, informative readouts in combination with intervention site identification. The characteristics of the proposed multi-criterion objective are illustrated with an in silico example. We further illustrate how an existing practically non-identifiable model for the chlorophyll fluorescence induction in a photosynthetic organism, D. salina, can be rendered identifiable by additional experiments with new readouts. Having data and profile likelihood samples at hand, the here proposed uncertainty quantification based on prediction samples from the profile likelihood provides a simple way for determining individual contributions of parameter uncertainties to uncertainties in model predictions. The uncertainty quantification of specific model predictions allows identifying regions, where model predictions have to be considered with care. Such uncertain regions can be used for a rational experimental design to render initially highly uncertain model predictions into certainty. Finally, our uncertainty quantification directly accounts for parameter interdependencies and parameter sensitivities of the specific prediction.

Robust stabilization of the Space Station in the presence of inertia matrix uncertainty

NASA Technical Reports Server (NTRS)

Wie, Bong; Liu, Qiang; Sunkel, John

1993-01-01

This paper presents a robust H-infinity full-state feedback control synthesis method for uncertain systems with D11 not equal to 0. The method is applied to the robust stabilization problem of the Space Station in the face of inertia matrix uncertainty. The control design objective is to find a robust controller that yields the largest stable hypercube in uncertain parameter space, while satisfying the nominal performance requirements. The significance of employing an uncertain plant model with D11 not equal 0 is demonstrated.

A linear quadratic regulator approach to the stabilization of uncertain linear systems

NASA Technical Reports Server (NTRS)

Shieh, L. S.; Sunkel, J. W.; Wang, Y. J.

1990-01-01

This paper presents a linear quadratic regulator approach to the stabilization of uncertain linear systems. The uncertain systems under consideration are described by state equations with the presence of time-varying unknown-but-bounded uncertainty matrices. The method is based on linear quadratic regulator (LQR) theory and Liapunov stability theory. The robust stabilizing control law for a given uncertain system can be easily constructed from the symmetric positive-definite solution of the associated augmented Riccati equation. The proposed approach can be applied to matched and/or mismatched systems with uncertainty matrices in which only their matrix norms are bounded by some prescribed values and/or their entries are bounded by some prescribed constraint sets. Several numerical examples are presented to illustrate the results.

Valuing Initial Teacher Education at Master's Level

ERIC Educational Resources Information Center

Brooks, Clare; Brant, Jacek; Abrahams, Ian; Yandell, John

2012-01-01

The future of Master's-level work in initial teacher education (ITE) in England seems uncertain. Whilst the coalition government has expressed support for Master's-level work, its recent White Paper focuses on teaching skills as the dominant form of professional development. This training discourse is in tension with the view of professional…

Robust decentralized hybrid adaptive output feedback fuzzy control for a class of large-scale MIMO nonlinear systems and its application to AHS.

PubMed

Huang, Yi-Shao; Liu, Wel-Ping; Wu, Min; Wang, Zheng-Wu

2014-09-01

This paper presents a novel observer-based decentralized hybrid adaptive fuzzy control scheme for a class of large-scale continuous-time multiple-input multiple-output (MIMO) uncertain nonlinear systems whose state variables are unmeasurable. The scheme integrates fuzzy logic systems, state observers, and strictly positive real conditions to deal with three issues in the control of a large-scale MIMO uncertain nonlinear system: algorithm design, controller singularity, and transient response. Then, the design of the hybrid adaptive fuzzy controller is extended to address a general large-scale uncertain nonlinear system. It is shown that the resultant closed-loop large-scale system keeps asymptotically stable and the tracking error converges to zero. The better characteristics of our scheme are demonstrated by simulations. Copyright © 2014. Published by Elsevier Ltd.

Uncertainty quantification for discrimination of nuclear events as violations of the comprehensive nuclear-test-ban treaty.

PubMed

Sloan, Jamison; Sun, Yunwei; Carrigan, Charles

2016-05-01

Enforcement of the Comprehensive Nuclear Test Ban Treaty (CTBT) will involve monitoring for radiologic indicators of underground nuclear explosions (UNEs). A UNE produces a variety of radioisotopes which then decay through connected radionuclide chains. A particular species of interest is xenon, namely the four isotopes (131m)Xe, (133m)Xe, (133)Xe, and (135)Xe. Due to their half lives, some of these isotopes can exist in the subsurface for more than 100 days. This convenient timescale, combined with modern detection capabilities, makes the xenon family a desirable candidate for UNE detection. Ratios of these isotopes as a function of time have been studied in the past for distinguishing nuclear explosions from civilian nuclear applications. However, the initial yields from UNEs have been treated as fixed values. In reality, these independent yields are uncertain to a large degree. This study quantifies the uncertainty in xenon ratios as a result of these uncertain initial conditions to better bound the values that xenon ratios can assume. We have successfully used a combination of analytical and sampling based statistical methods to reliably bound xenon isotopic ratios. We have also conducted a sensitivity analysis and found that xenon isotopic ratios are primarily sensitive to only a few of many uncertain initial conditions. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Finite-time output feedback control of uncertain switched systems via sliding mode design

NASA Astrophysics Data System (ADS)

Zhao, Haijuan; Niu, Yugang; Song, Jun

2018-04-01

The problem of sliding mode control (SMC) is investigated for a class of uncertain switched systems subject to unmeasurable state and assigned finite (possible short) time constraint. A key issue is how to ensure the finite-time boundedness (FTB) of system state during reaching phase and sliding motion phase. To this end, a state observer is constructed to estimate the unmeasured states. And then, a state estimate-based SMC law is designed such that the state trajectories can be driven onto the specified integral sliding surface during the assigned finite time interval. By means of partitioning strategy, the corresponding FTB over reaching phase and sliding motion phase are guaranteed and the sufficient conditions are derived via average dwell time technique. Finally, an illustrative example is given to illustrate the proposed method.

Single-axis gyroscopic motion with uncertain angular velocity about spin axis

NASA Technical Reports Server (NTRS)

Singh, S. N.

1977-01-01

A differential game approach is presented for studying the response of a gyro by treating the controlled angular velocity about the input axis as the evader, and the bounded but uncertain angular velocity about the spin axis as the pursuer. When the uncertain angular velocity about the spin axis desires to force the gyro to saturation a differential game problem with two terminal surfaces results, whereas when the evader desires to attain the equilibrium state the usual game with single terminal manifold arises. A barrier, delineating the capture zone (CZ) in which the gyro can attain saturation and the escape zone (EZ) in which the evader avoids saturation is obtained. The CZ is further delineated into two subregions such that the states in each subregion can be forced on a definite target manifold. The application of the game theoretic approach to Control Moment Gyro is briefly discussed.

Deterministic physical systems under uncertain initial conditions: the case of maximum entropy applied to projectile motion

NASA Astrophysics Data System (ADS)

Montecinos, Alejandra; Davis, Sergio; Peralta, Joaquín

2018-07-01

The kinematics and dynamics of deterministic physical systems have been a foundation of our understanding of the world since Galileo and Newton. For real systems, however, uncertainty is largely present via external forces such as friction or lack of precise knowledge about the initial conditions of the system. In this work we focus on the latter case and describe the use of inference methodologies in solving the statistical properties of classical systems subject to uncertain initial conditions. In particular we describe the application of the formalism of maximum entropy (MaxEnt) inference to the problem of projectile motion, given information about the average horizontal range over many realizations. By using MaxEnt we can invert the problem and use the provided information on the average range to reduce the original uncertainty in the initial conditions. Also, additional insight into the initial condition's probabilities, and the projectile path distribution itself, can be achieved based on the value of the average horizontal range. The wide applicability of this procedure, as well as its ease of use, reveals a useful tool with which to revisit a large number of physics problems, from classrooms to frontier research.

Synchronization transmission of laser pattern signal within uncertain switched network

NASA Astrophysics Data System (ADS)

Lü, Ling; Li, Chengren; Li, Gang; Sun, Ao; Yan, Zhe; Rong, Tingting; Gao, Yan

2017-06-01

We propose a new technology for synchronization transmission of laser pattern signal within uncertain network with controllable topology. In synchronization process, the connection of dynamic network can vary at all time according to different demands. Especially, we construct the Lyapunov function of network through designing a special semi-positive definite function, and the synchronization transmission of laser pattern signal within uncertain network with controllable topology can be realized perfectly, which effectively avoids the complicated calculation for solving the second largest eignvalue of the coupling matrix of the dynamic network in order to obtain the network synchronization condition. At the same time, the uncertain parameters in dynamic equations belonging to network nodes can also be identified accurately via designing the identification laws of uncertain parameters. In addition, there are not any limitations for the synchronization target of network in the new technology, in other words, the target can either be a state variable signal of an arbitrary node within the network or an exterior signal.

Probability-based constrained MPC for structured uncertain systems with state and random input delays

NASA Astrophysics Data System (ADS)

Lu, Jianbo; Li, Dewei; Xi, Yugeng

2013-07-01

This article is concerned with probability-based constrained model predictive control (MPC) for systems with both structured uncertainties and time delays, where a random input delay and multiple fixed state delays are included. The process of input delay is governed by a discrete-time finite-state Markov chain. By invoking an appropriate augmented state, the system is transformed into a standard structured uncertain time-delay Markov jump linear system (MJLS). For the resulting system, a multi-step feedback control law is utilised to minimise an upper bound on the expected value of performance objective. The proposed design has been proved to stabilise the closed-loop system in the mean square sense and to guarantee constraints on control inputs and system states. Finally, a numerical example is given to illustrate the proposed results.

Adaptive fixed-time control for cluster synchronisation of coupled complex networks with uncertain disturbances

NASA Astrophysics Data System (ADS)

Jiang, Shengqin; Lu, Xiaobo; Cai, Guoliang; Cai, Shuiming

2017-12-01

This paper focuses on the cluster synchronisation problem of coupled complex networks with uncertain disturbances under an adaptive fixed-time control strategy. To begin with, complex dynamical networks with community structure which are subject to uncertain disturbances are taken into account. Then, a novel adaptive control strategy combined with fixed-time techniques is proposed to guarantee the nodes in the communities to desired states in a settling time. In addition, the stability of complex error systems is theoretically proved based on Lyapunov stability theorem. At last, two examples are presented to verify the effectiveness of the proposed adaptive fixed-time control.

Statement Testimony of The Honorable Zachary J. Lemnios Director, Defense Research and Engineering Before the United States House of Representatives Committee on Armed Services Subcommittee on Terrorism, Unconventional Threats and Capabilities

DTIC Science & Technology

2010-03-23

nationwide virtual science libary adapted for Afghanistan’s needs. Prepare for an Uncertain Future In preparing for an uncertain future, a...to assess the military implications of the ubiquitous availability of high performance analog, digital , electro-optical, radio frequency and signal

A new framework for quantifying uncertainties in modelling studies for future climates - how more certain are CMIP5 precipitation and temperature simulations compared to CMIP3?

NASA Astrophysics Data System (ADS)

Sharma, A.; Woldemeskel, F. M.; Sivakumar, B.; Mehrotra, R.

2014-12-01

We outline a new framework for assessing uncertainties in model simulations, be they hydro-ecological simulations for known scenarios, or climate simulations for assumed scenarios representing the future. This framework is illustrated here using GCM projections for future climates for hydrologically relevant variables (precipitation and temperature), with the uncertainty segregated into three dominant components - model uncertainty, scenario uncertainty (representing greenhouse gas emission scenarios), and ensemble uncertainty (representing uncertain initial conditions and states). A novel uncertainty metric, the Square Root Error Variance (SREV), is used to quantify the uncertainties involved. The SREV requires: (1) Interpolating raw and corrected GCM outputs to a common grid; (2) Converting these to percentiles; (3) Estimating SREV for model, scenario, initial condition and total uncertainty at each percentile; and (4) Transforming SREV to a time series. The outcome is a spatially varying series of SREVs associated with each model that can be used to assess how uncertain the system is at each simulated point or time. This framework, while illustrated in a climate change context, is completely applicable for assessment of uncertainties any modelling framework may be subject to. The proposed method is applied to monthly precipitation and temperature from 6 CMIP3 and 13 CMIP5 GCMs across the world. For CMIP3, B1, A1B and A2 scenarios whereas for CMIP5, RCP2.6, RCP4.5 and RCP8.5 representing low, medium and high emissions are considered. For both CMIP3 and CMIP5, model structure is the largest source of uncertainty, which reduces significantly after correcting for biases. Scenario uncertainly increases, especially for temperature, in future due to divergence of the three emission scenarios analysed. While CMIP5 precipitation simulations exhibit a small reduction in total uncertainty over CMIP3, there is almost no reduction observed for temperature projections. Estimation of uncertainty in both space and time sheds lights on the spatial and temporal patterns of uncertainties in GCM outputs, providing an effective platform for risk-based assessments of any alternate plans or decisions that may be formulated using GCM simulations.

Regional robust stabilisation and domain-of-attraction estimation for MIMO uncertain nonlinear systems with input saturation

NASA Astrophysics Data System (ADS)

Azizi, S.; Torres, L. A. B.; Palhares, R. M.

2018-01-01

The regional robust stabilisation by means of linear time-invariant state feedback control for a class of uncertain MIMO nonlinear systems with parametric uncertainties and control input saturation is investigated. The nonlinear systems are described in a differential algebraic representation and the regional stability is handled considering the largest ellipsoidal domain-of-attraction (DOA) inside a given polytopic region in the state space. A novel set of sufficient Linear Matrix Inequality (LMI) conditions with new auxiliary decision variables are developed aiming to design less conservative linear state feedback controllers with corresponding larger DOAs, by considering the polytopic description of the saturated inputs. A few examples are presented showing favourable comparisons with recently published similar control design methodologies.

A Robust Adaptive Unscented Kalman Filter for Nonlinear Estimation with Uncertain Noise Covariance.

PubMed

Zheng, Binqi; Fu, Pengcheng; Li, Baoqing; Yuan, Xiaobing

2018-03-07

The Unscented Kalman filter (UKF) may suffer from performance degradation and even divergence while mismatch between the noise distribution assumed as a priori by users and the actual ones in a real nonlinear system. To resolve this problem, this paper proposes a robust adaptive UKF (RAUKF) to improve the accuracy and robustness of state estimation with uncertain noise covariance. More specifically, at each timestep, a standard UKF will be implemented first to obtain the state estimations using the new acquired measurement data. Then an online fault-detection mechanism is adopted to judge if it is necessary to update current noise covariance. If necessary, innovation-based method and residual-based method are used to calculate the estimations of current noise covariance of process and measurement, respectively. By utilizing a weighting factor, the filter will combine the last noise covariance matrices with the estimations as the new noise covariance matrices. Finally, the state estimations will be corrected according to the new noise covariance matrices and previous state estimations. Compared with the standard UKF and other adaptive UKF algorithms, RAUKF converges faster to the actual noise covariance and thus achieves a better performance in terms of robustness, accuracy, and computation for nonlinear estimation with uncertain noise covariance, which is demonstrated by the simulation results.

A Robust Adaptive Unscented Kalman Filter for Nonlinear Estimation with Uncertain Noise Covariance

PubMed Central

Zheng, Binqi; Yuan, Xiaobing

2018-01-01

The Unscented Kalman filter (UKF) may suffer from performance degradation and even divergence while mismatch between the noise distribution assumed as a priori by users and the actual ones in a real nonlinear system. To resolve this problem, this paper proposes a robust adaptive UKF (RAUKF) to improve the accuracy and robustness of state estimation with uncertain noise covariance. More specifically, at each timestep, a standard UKF will be implemented first to obtain the state estimations using the new acquired measurement data. Then an online fault-detection mechanism is adopted to judge if it is necessary to update current noise covariance. If necessary, innovation-based method and residual-based method are used to calculate the estimations of current noise covariance of process and measurement, respectively. By utilizing a weighting factor, the filter will combine the last noise covariance matrices with the estimations as the new noise covariance matrices. Finally, the state estimations will be corrected according to the new noise covariance matrices and previous state estimations. Compared with the standard UKF and other adaptive UKF algorithms, RAUKF converges faster to the actual noise covariance and thus achieves a better performance in terms of robustness, accuracy, and computation for nonlinear estimation with uncertain noise covariance, which is demonstrated by the simulation results. PMID:29518960

Long-time uncertainty propagation using generalized polynomial chaos and flow map composition

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

Luchtenburg, Dirk M., E-mail: dluchten@cooper.edu; Brunton, Steven L.; Rowley, Clarence W.

2014-10-01

We present an efficient and accurate method for long-time uncertainty propagation in dynamical systems. Uncertain initial conditions and parameters are both addressed. The method approximates the intermediate short-time flow maps by spectral polynomial bases, as in the generalized polynomial chaos (gPC) method, and uses flow map composition to construct the long-time flow map. In contrast to the gPC method, this approach has spectral error convergence for both short and long integration times. The short-time flow map is characterized by small stretching and folding of the associated trajectories and hence can be well represented by a relatively low-degree basis. The compositionmore » of these low-degree polynomial bases then accurately describes the uncertainty behavior for long integration times. The key to the method is that the degree of the resulting polynomial approximation increases exponentially in the number of time intervals, while the number of polynomial coefficients either remains constant (for an autonomous system) or increases linearly in the number of time intervals (for a non-autonomous system). The findings are illustrated on several numerical examples including a nonlinear ordinary differential equation (ODE) with an uncertain initial condition, a linear ODE with an uncertain model parameter, and a two-dimensional, non-autonomous double gyre flow.« less

Appropriateness of early management of newly diagnosed Crohn's disease in a European population-based cohort.

PubMed

Juillerat, Pascal; Pittet, Valérie; Mottet, Christian; Felley, Christian; Gonvers, Jean-Jacques; Vader, John-Paul; Burnand, Bernard; Froehlich, Florian; Wolters, Frank L; Stockbrügger, Reinhold W; Michetti, Pierre

2010-12-01

The European Panel on the Appropriateness of Crohn's disease Therapy (EPACT) has developed appropriateness criteria. We have applied these criteria retrospectively to the population-based inception cohort of Crohn's disease (CD) patients of the European Collaborative Study Group on Inflammatory Bowel Disease (EC-IBD). A total of 426 diagnosed CD patients from 13 European centers were enrolled at the time of diagnosis (first flare, naive patients). We used the EPACT definitions to identify 247 patients with active luminal CD. We then assessed the appropriateness of the initial drug prescription according to the EPACT criteria. Among the cohort patients 163 suffered from mild-to-moderate CD and 84 from severe CD. Among the mild-to-moderate disease group, 96 patients (59%) received an appropriate treatment, whereas for 66 patients (40%) the treatment was uncertain and in one case (1%) inappropriate. Among the severe disease group, 86% were treated medically and 14% required surgery. 59 (70%) were appropriately treated, whereas for one patient (1%) the procedure was considered uncertain and for 24 patients (29%) inappropriate. Initial treatment was appropriate in the majority of cases for non-complicated luminal CD. Inappropriate or uncertain treatment was given in a significant minority of patients, with an increased potential risk of adverse events.

Decentralized Adaptive Control of Systems with Uncertain Interconnections, Plant-Model Mismatch and Actuator Failures

NASA Technical Reports Server (NTRS)

Patre, Parag; Joshi, Suresh M.

2011-01-01

Decentralized adaptive control is considered for systems consisting of multiple interconnected subsystems. It is assumed that each subsystem s parameters are uncertain and the interconnection parameters are not known. In addition, mismatch can exist between each subsystem and its reference model. A strictly decentralized adaptive control scheme is developed, wherein each subsystem has access only to its own state but has the knowledge of all reference model states. The mismatch is estimated online for each subsystem and the mismatch estimates are used to adaptively modify the corresponding reference models. The adaptive control scheme is extended to the case with actuator failures in addition to mismatch.

Data Assimilation - Advances and Applications

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

Williams, Brian J.

2014-07-30

This presentation provides an overview of data assimilation (model calibration) for complex computer experiments. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Utilization of surrogate models and empirical adjustment for model form error in code calibration form the basis for the statistical methodology considered. The role of probabilistic code calibration in supporting code validation is discussed. Incorporation of model form uncertainty in rigorous uncertainty quantification (UQ) analyses is also addressed. Design criteria used within a batchmore » sequential design algorithm are introduced for efficiently achieving predictive maturity and improved code calibration. Predictive maturity refers to obtaining stable predictive inference with calibrated computer codes. These approaches allow for augmentation of initial experiment designs for collecting new physical data. A standard framework for data assimilation is presented and techniques for updating the posterior distribution of the state variables based on particle filtering and the ensemble Kalman filter are introduced.« less

Non-specific effects of vaccines: plausible and potentially important, but implications uncertain.

PubMed

Pollard, Andrew J; Finn, Adam; Curtis, Nigel

2017-11-01

Non-specific effects (NSE) or heterologous effects of vaccines are proposed to explain observations in some studies that certain vaccines have an impact beyond the direct protection against infection with the specific pathogen for which the vaccines were designed. The importance and implications of such effects remain controversial. There are several known immunological mechanisms which could lead to NSE, since it is widely recognised that the generation of specific immunity is initiated by non-specific innate immune mechanisms that may also have wider effects on adaptive immune function. However, there are no published studies that demonstrate a mechanistic link between such immunological phenomena and clinically relevant NSE in humans. While it is highly plausible that some vaccines do have NSE, their magnitude and duration, and thus importance, remain uncertain. Although the WHO recently concluded that current evidence does not justify changes to immunisation policy, further studies of sufficient size and quality are needed to assess the importance of NSE for all-cause mortality. This could provide insights into vaccine immunobiology with important implications for infant health and survival. © 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.

Robust passive control for a class of uncertain neutral systems based on sliding mode observer.

PubMed

Liu, Zhen; Zhao, Lin; Kao, Yonggui; Gao, Cunchen

2017-01-01

The passivity-based sliding mode control (SMC) problem for a class of uncertain neutral systems with unmeasured states is investigated. Firstly, a particular non-fragile state observer is designed to generate the estimations of the system states, based upon which a novel integral-type sliding surface function is established for the control process. Secondly, a new sufficient condition for robust asymptotic stability and passivity of the resultant sliding mode dynamics (SMDs) is obtained in terms of linear matrix inequalities (LMIs). Thirdly, the finite-time reachability of the predesigned sliding surface is ensured by resorting to a novel adaptive SMC law. Finally, the validity and superiority of the scheme are justified via several examples. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Robot Path Planning in Uncertain Environments: A Language Measure-theoretic Approach

DTIC Science & Technology

2014-01-01

Paper DS-14-1028 to appear in the Special Issue on Stochastic Models, Control and Algorithms in Robotics, ASME Journal of Dynamic Systems...Measurement and Control Robot Path Planning in Uncertain Environments: A Language Measure-theoretic Approach⋆ Devesh K. Jha† Yue Li† Thomas A. Wettergren‡† Asok...algorithm, called ν⋆, that was formulated in the framework of probabilistic finite state automata (PFSA) and language measure from a control -theoretic

Quantifying potential health impacts of cadmium in cigarettes on smoker risk of lung cancer: a portfolio-of-mechanisms approach.

PubMed

Cox, Louis Anthony Tony

2006-12-01

This article introduces an approach to estimating the uncertain potential effects on lung cancer risk of removing a particular constituent, cadmium (Cd), from cigarette smoke, given the useful but incomplete scientific information available about its modes of action. The approach considers normal cell proliferation; DNA repair inhibition in normal cells affected by initiating events; proliferation, promotion, and progression of initiated cells; and death or sparing of initiated and malignant cells as they are further transformed to become fully tumorigenic. Rather than estimating unmeasured model parameters by curve fitting to epidemiological or animal experimental tumor data, we attempt rough estimates of parameters based on their biological interpretations and comparison to corresponding genetic polymorphism data. The resulting parameter estimates are admittedly uncertain and approximate, but they suggest a portfolio approach to estimating impacts of removing Cd that gives usefully robust conclusions. This approach views Cd as creating a portfolio of uncertain health impacts that can be expressed as biologically independent relative risk factors having clear mechanistic interpretations. Because Cd can act through many distinct biological mechanisms, it appears likely (subjective probability greater than 40%) that removing Cd from cigarette smoke would reduce smoker risks of lung cancer by at least 10%, although it is possible (consistent with what is known) that the true effect could be much larger or smaller. Conservative estimates and assumptions made in this calculation suggest that the true impact could be greater for some smokers. This conclusion appears to be robust to many scientific uncertainties about Cd and smoking effects.

Possible world based consistency learning model for clustering and classifying uncertain data.

PubMed

Liu, Han; Zhang, Xianchao; Zhang, Xiaotong

2018-06-01

Possible world has shown to be effective for handling various types of data uncertainty in uncertain data management. However, few uncertain data clustering and classification algorithms are proposed based on possible world. Moreover, existing possible world based algorithms suffer from the following issues: (1) they deal with each possible world independently and ignore the consistency principle across different possible worlds; (2) they require the extra post-processing procedure to obtain the final result, which causes that the effectiveness highly relies on the post-processing method and the efficiency is also not very good. In this paper, we propose a novel possible world based consistency learning model for uncertain data, which can be extended both for clustering and classifying uncertain data. This model utilizes the consistency principle to learn a consensus affinity matrix for uncertain data, which can make full use of the information across different possible worlds and then improve the clustering and classification performance. Meanwhile, this model imposes a new rank constraint on the Laplacian matrix of the consensus affinity matrix, thereby ensuring that the number of connected components in the consensus affinity matrix is exactly equal to the number of classes. This also means that the clustering and classification results can be directly obtained without any post-processing procedure. Furthermore, for the clustering and classification tasks, we respectively derive the efficient optimization methods to solve the proposed model. Experimental results on real benchmark datasets and real world uncertain datasets show that the proposed model outperforms the state-of-the-art uncertain data clustering and classification algorithms in effectiveness and performs competitively in efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stability of uncertain impulsive complex-variable chaotic systems with time-varying delays.

PubMed

Zheng, Song

2015-09-01

In this paper, the robust exponential stabilization of uncertain impulsive complex-variable chaotic delayed systems is considered with parameters perturbation and delayed impulses. It is assumed that the considered complex-variable chaotic systems have bounded parametric uncertainties together with the state variables on the impulses related to the time-varying delays. Based on the theories of adaptive control and impulsive control, some less conservative and easily verified stability criteria are established for a class of complex-variable chaotic delayed systems with delayed impulses. Some numerical simulations are given to validate the effectiveness of the proposed criteria of impulsive stabilization for uncertain complex-variable chaotic delayed systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Regenerating yellow birch in the Lake States

Treesearch

Richard M. Godman; Gayne G. Erdmann

1992-01-01

The future of the yellow birch supply in the Lake States is uncertain. Growing-stock volume has declined more than one third since 1963, prompting the search for better ways to handle the difficult job of regenerating the species.

Towards adjoint-based inversion of time-dependent mantle convection with nonlinear viscosity

NASA Astrophysics Data System (ADS)

Li, Dunzhu; Gurnis, Michael; Stadler, Georg

2017-04-01

We develop and study an adjoint-based inversion method for the simultaneous recovery of initial temperature conditions and viscosity parameters in time-dependent mantle convection from the current mantle temperature and historic plate motion. Based on a realistic rheological model with temperature-dependent and strain-rate-dependent viscosity, we formulate the inversion as a PDE-constrained optimization problem. The objective functional includes the misfit of surface velocity (plate motion) history, the misfit of the current mantle temperature, and a regularization for the uncertain initial condition. The gradient of this functional with respect to the initial temperature and the uncertain viscosity parameters is computed by solving the adjoint of the mantle convection equations. This gradient is used in a pre-conditioned quasi-Newton minimization algorithm. We study the prospects and limitations of the inversion, as well as the computational performance of the method using two synthetic problems, a sinking cylinder and a realistic subduction model. The subduction model is characterized by the migration of a ridge toward a trench whereby both plate motions and subduction evolve. The results demonstrate: (1) for known viscosity parameters, the initial temperature can be well recovered, as in previous initial condition-only inversions where the effective viscosity was given; (2) for known initial temperature, viscosity parameters can be recovered accurately, despite the existence of trade-offs due to ill-conditioning; (3) for the joint inversion of initial condition and viscosity parameters, initial condition and effective viscosity can be reasonably recovered, but the high dimension of the parameter space and the resulting ill-posedness may limit recovery of viscosity parameters.

Fasting, but Not Aging, Dramatically Alters the Redox Status of Cysteine Residues on Proteins in Drosophila melanogaster

PubMed Central

Menger, Katja E.; James, Andrew M.; Cochemé, Helena M.; Harbour, Michael E.; Chouchani, Edward T.; Ding, Shujing; Fearnley, Ian M.; Partridge, Linda; Murphy, Michael P.

2015-01-01

Summary Altering the redox state of cysteine residues on protein surfaces is an important response to environmental challenges. Although aging and fasting alter many redox processes, the role of cysteine residues is uncertain. To address this, we used a redox proteomic technique, oxidative isotope-coded affinity tags (OxICAT), to assess cysteine-residue redox changes in Drosophila melanogaster during aging and fasting. This approach enabled us to simultaneously identify and quantify the redox state of several hundred cysteine residues in vivo. Cysteine residues within young flies had a bimodal distribution with peaks at ∼10% and ∼85% reversibly oxidized. Surprisingly, these cysteine residues did not become more oxidized with age. In contrast, 24 hr of fasting dramatically oxidized cysteine residues that were reduced under fed conditions while also reducing cysteine residues that were initially oxidized. We conclude that fasting, but not aging, dramatically alters cysteine-residue redox status in D. melanogaster. PMID:26095360

An industry perspective on commercial radioactive waste disposal conditions and trends.

PubMed

Romano, Stephen A

2006-11-01

The United States is presently served by Class-A, -B and -C low-level radioactive waste and naturally-occurring and accelerator-produced radioactive material disposal sites in Washington and South Carolina; a Class-A and mixed waste disposal site in Utah that also accepts naturally-occurring radioactive material; and hazardous and solid waste facilities and uranium mill tailings sites that accept certain radioactive materials on a site-specific basis. The Washington site only accepts low-level radioactive waste from 11 western states due to interstate Compact restrictions on waste importation. The South Carolina site will be subject to geographic service area restrictions beginning 1 July 2008, after which only three states will have continued access. The Utah site dominates the commercial Class-A and mixed waste disposal market due to generally lower state fees than apply in South Carolina. To expand existing commercial services, an existing hazardous waste site in western Texas is seeking a Class-A, -B and -C and mixed waste disposal license. With that exception, no new Compact facilities are proposed. This fluid, uncertain situation has inspired national level rulemaking initiatives and policy studies, as well as alternative disposal practices for certain low-activity materials.

Observer-Based Adaptive NN Control for a Class of Uncertain Nonlinear Systems With Nonsymmetric Input Saturation.

PubMed

Yong-Feng Gao; Xi-Ming Sun; Changyun Wen; Wei Wang

2017-07-01

This paper is concerned with the problem of adaptive tracking control for a class of uncertain nonlinear systems with nonsymmetric input saturation and immeasurable states. The radial basis function of neural network (NN) is employed to approximate unknown functions, and an NN state observer is designed to estimate the immeasurable states. To analyze the effect of input saturation, an auxiliary system is employed. By the aid of adaptive backstepping technique, an adaptive tracking control approach is developed. Under the proposed adaptive tracking controller, the boundedness of all the signals in the closed-loop system is achieved. Moreover, distinct from most of the existing references, the tracking error can be bounded by an explicit function of design parameters and saturation input error. Finally, an example is given to show the effectiveness of the proposed method.

Petitioning for Involuntary Commitment for Chemical Dependency by Medical Services.

PubMed

Lamoureux, Ian C; Schutt, Paul E; Rasmussen, Keith G

2017-09-01

Patients who have chemical dependency (CD) are commonly encountered on medical and surgical wards, often for illnesses and injuries sustained as a direct result of their substance abuse. When these patients are repeatedly admitted to the hospital in certain states that provide a legal framework to commit chemically dependent persons to a treatment facility, clinicians often wonder whether they should initiate that process. Should consulting psychiatrists choose to initiate the commitment process, they put into motion a resource-intensive, time-consuming mechanism, with uncertain outcomes, both in the courtroom and at the bedside. Petitioning for involuntary commitment to chemical dependency treatment of a patient from medical and surgical services is poorly understood. In this study, we examined a series of patients for whom petitions for judicial commitment in the state of Minnesota were entered over a 12-month period, and evaluated the likelihood of commitment to treatment, the demographics of patients involved, and the outcomes for this series of patients. Three vignettes are presented to illustrate the severity of these patients' illnesses and potential outcomes of the process. We further describe potential limitations of the commitment system and alternatives to CD commitment that could be explored further. © 2017 American Academy of Psychiatry and the Law.

Non-fragile observer-based output feedback control for polytopic uncertain system under distributed model predictive control approach

NASA Astrophysics Data System (ADS)

Zhu, Kaiqun; Song, Yan; Zhang, Sunjie; Zhong, Zhaozhun

2017-07-01

In this paper, a non-fragile observer-based output feedback control problem for the polytopic uncertain system under distributed model predictive control (MPC) approach is discussed. By decomposing the global system into some subsystems, the computation complexity is reduced, so it follows that the online designing time can be saved.Moreover, an observer-based output feedback control algorithm is proposed in the framework of distributed MPC to deal with the difficulties in obtaining the states measurements. In this way, the presented observer-based output-feedback MPC strategy is more flexible and applicable in practice than the traditional state-feedback one. What is more, the non-fragility of the controller has been taken into consideration in favour of increasing the robustness of the polytopic uncertain system. After that, a sufficient stability criterion is presented by using Lyapunov-like functional approach, meanwhile, the corresponding control law and the upper bound of the quadratic cost function are derived by solving an optimisation subject to convex constraints. Finally, some simulation examples are employed to show the effectiveness of the method.

Output Feedback-Based Boundary Control of Uncertain Coupled Semilinear Parabolic PDE Using Neurodynamic Programming.

PubMed

Talaei, Behzad; Jagannathan, Sarangapani; Singler, John

2018-04-01

In this paper, neurodynamic programming-based output feedback boundary control of distributed parameter systems governed by uncertain coupled semilinear parabolic partial differential equations (PDEs) under Neumann or Dirichlet boundary control conditions is introduced. First, Hamilton-Jacobi-Bellman (HJB) equation is formulated in the original PDE domain and the optimal control policy is derived using the value functional as the solution of the HJB equation. Subsequently, a novel observer is developed to estimate the system states given the uncertain nonlinearity in PDE dynamics and measured outputs. Consequently, the suboptimal boundary control policy is obtained by forward-in-time estimation of the value functional using a neural network (NN)-based online approximator and estimated state vector obtained from the NN observer. Novel adaptive tuning laws in continuous time are proposed for learning the value functional online to satisfy the HJB equation along system trajectories while ensuring the closed-loop stability. Local uniformly ultimate boundedness of the closed-loop system is verified by using Lyapunov theory. The performance of the proposed controller is verified via simulation on an unstable coupled diffusion reaction process.

Models and mechanisms of anxiety: evidence from startle studies

PubMed Central

Grillon, Christian

2009-01-01

Rationale Preclinical data indicates that threat stimuli elicit two classes of defensive behaviors, those that are associated with imminent danger and are characterized by avoidance or fight (fear), and those that are associated with temporally uncertain danger and are characterized by sustained apprehension and hypervigilance (anxiety). Objective To 1) review evidence for a distinction between fear and anxiety in animal and human experimental models using the startle reflex as an operational measure of aversive states, 2) describe experimental models of anxiety, as opposed to fear, in humans, 3) examine the relevance of these models to clinical anxiety. Results The distinction between phasic fear to imminent threat and sustained anxiety to temporally uncertain danger is suggested by psychopharmacological and behavioral evidence from ethological studies and can be traced back to distinct neuroanatomical systems, the amygdala and the bed nucleus of the stria terminalis. Experimental models of anxiety, not fear, are relevant to non-phobic anxiety disorders. Conclusions Progress in our understanding of normal and abnormal anxiety is critically dependent on our ability to model sustained aversive states to temporally uncertain threat. PMID:18058089

On the modeling of the 2010 Gulf of Mexico Oil Spill

NASA Astrophysics Data System (ADS)

Mariano, A. J.; Kourafalou, V. H.; Srinivasan, A.; Kang, H.; Halliwell, G. R.; Ryan, E. H.; Roffer, M.

2011-09-01

Two oil particle trajectory forecasting systems were developed and applied to the 2010 Deepwater Horizon Oil Spill in the Gulf of Mexico. Both systems use ocean current fields from high-resolution numerical ocean circulation model simulations, Lagrangian stochastic models to represent unresolved sub-grid scale variability to advect oil particles, and Monte Carlo-based schemes for representing uncertain biochemical and physical processes. The first system assumes two-dimensional particle motion at the ocean surface, the oil is in one state, and the particle removal is modeled as a Monte Carlo process parameterized by a one number removal rate. Oil particles are seeded using both initial conditions based on observations and particles released at the location of the Maconda well. The initial conditions (ICs) of oil particle location for the two-dimensional surface oil trajectory forecasts are based on a fusing of all available information including satellite-based analyses. The resulting oil map is digitized into a shape file within which a polygon filling software generates longitude and latitude with variable particle density depending on the amount of oil present in the observations for the IC. The more complex system assumes three (light, medium, heavy) states for the oil, each state has a different removal rate in the Monte Carlo process, three-dimensional particle motion, and a particle size-dependent oil mixing model. Simulations from the two-dimensional forecast system produced results that qualitatively agreed with the uncertain "truth" fields. These simulations validated the use of our Monte Carlo scheme for representing oil removal by evaporation and other weathering processes. Eulerian velocity fields for predicting particle motion from data-assimilative models produced better particle trajectory distributions than a free running model with no data assimilation. Monte Carlo simulations of the three-dimensional oil particle trajectory, whose ensembles were generated by perturbing the size of the oil particles and the fraction in a given size range that are released at depth, the two largest unknowns in this problem. 36 realizations of the model were run with only subsurface oil releases. An average of these results yields that after three months, about 25% of the oil remains in the water column and that most of the oil is below 800 m.

Communicating Uncertain Experimental Evidence

ERIC Educational Resources Information Center

Davis, Alexander L.; Fischhoff, Baruch

2014-01-01

Four experiments examined when laypeople attribute unexpected experimental outcomes to error, in foresight and in hindsight, along with their judgments of whether the data should be published. Participants read vignettes describing hypothetical experiments, along with the result of the initial observation, considered as either a possibility…

Use of the Coronary Artery Calcium Score in Discussion of Initiation of Statin Therapy in Primary Prevention.

PubMed

Michos, Erin D; Blaha, Michael J; Blumenthal, Roger S

2017-12-01

Clinical guidelines for instituting pharmacotherapy for the primary prevention of atherosclerotic cardiovascular disease (ASCVD), specifically lipid management and aspirin, have long been based on absolute risk. However, lipid management in the current era remains challenging to both patients and clinicians in the setting of somewhat discordant recommendations from various organizations. All guidelines endorse the use of statins for primary prevention for those at sufficient absolute risk, and treatment recommendations are generally "risk-based" rather than exclusively targeting specific low-density lipoprotein cholesterol levels. Nonetheless, guidelines differ in relation to the risk threshold for initiation and the intensity of statin treatment. The key concept of the clinician-patient risk discussion introduced in the 2013 American College of Cardiology/American Heart Association cholesterol guidelines is a process that addresses the potential for ASCVD risk reduction with statin treatment, potential for adverse treatment effects, patient preferences, encouragement of heart-healthy lifestyle, and management of other risk factors. However, operationalizing the clinician-patient risk discussion requires effective communication of the most accurate and personalized risk information. In this article, we review our treatment approach for the appropriate use of coronary artery calcium testing in the intermediate-risk patient to guide shared decision making. The decision to initiate or intensify statin therapy may be uncertain across a broad range of estimated 10-year ASCVD risk of 5% to 20%, and coronary artery calcium testing can reclassify risk upward or downward in approximately 50% of this group to inform the risk discussion. We conclude with 2 case-based examples of uncertain risk and uncertain statin therapeutic benefit to illustrate execution of the clinician-patient risk discussion. Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

An approach to quantifying the efficiency of a Bayesian filter

USDA-ARS?s Scientific Manuscript database

Data assimilation is defined as the Bayesian conditioning of uncertain model simulations on observations for the purpose of reducing uncertainty about model states. Practical data assimilation applications require that simplifying assumptions be made about the prior and posterior state distributions...

Learning to integrate reactivity and deliberation in uncertain planning and scheduling problems

NASA Technical Reports Server (NTRS)

Chien, Steve A.; Gervasio, Melinda T.; Dejong, Gerald F.

1992-01-01

This paper describes an approach to planning and scheduling in uncertain domains. In this approach, a system divides a task on a goal by goal basis into reactive and deliberative components. Initially, a task is handled entirely reactively. When failures occur, the system changes the reactive/deliverative goal division by moving goals into the deliberative component. Because our approach attempts to minimize the number of deliberative goals, we call our approach Minimal Deliberation (MD). Because MD allows goals to be treated reactively, it gains some of the advantages of reactive systems: computational efficiency, the ability to deal with noise and non-deterministic effects, and the ability to take advantage of unforseen opportunities. However, because MD can fall back upon deliberation, it can also provide some of the guarantees of classical planning, such as the ability to deal with complex goal interactions. This paper describes the Minimal Deliberation approach to integrating reactivity and deliberation and describe an ongoing application of the approach to an uncertain planning and scheduling domain.

Nonparametric Discrete Survival Function Estimation with Uncertain Endpoints Using an Internal Validation Subsample

PubMed Central

Zee, Jarcy; Xie, Sharon X.

2015-01-01

Summary When a true survival endpoint cannot be assessed for some subjects, an alternative endpoint that measures the true endpoint with error may be collected, which often occurs when obtaining the true endpoint is too invasive or costly. We develop an estimated likelihood function for the situation where we have both uncertain endpoints for all participants and true endpoints for only a subset of participants. We propose a nonparametric maximum estimated likelihood estimator of the discrete survival function of time to the true endpoint. We show that the proposed estimator is consistent and asymptotically normal. We demonstrate through extensive simulations that the proposed estimator has little bias compared to the naïve Kaplan-Meier survival function estimator, which uses only uncertain endpoints, and more efficient with moderate missingness compared to the complete-case Kaplan-Meier survival function estimator, which uses only available true endpoints. Finally, we apply the proposed method to a dataset for estimating the risk of developing Alzheimer's disease from the Alzheimer's Disease Neuroimaging Initiative. PMID:25916510

Resource utilization and outcomes management: opportunities for the entrepreneurial pathologist.

PubMed

Vance, R P

1997-01-01

Pathologists and laboratory managers are facing an increasingly uncertain place in the emerging managed care marketplace. Among the various opportunities available is outcomes management. The role of benchmarking in outcomes management and the initial steps in developing outcomes management programs are presented.

AN AMMONIA EMISSION INVENTORY FOR FERTILIZER APPLICATION IN THE UNITED STATES. (R826371C006)

EPA Science Inventory

Fertilizer application represents a significant fraction of ammonia emissions from all sources in the United States. Previously published ammonia inventories have generally suffered from poor spatial and temporal resolution, erroneous activity levels, and highly uncertain emis...

Robot Path Planning in Uncertain Environments: A Language-Measure-Theoretic Approach

DTIC Science & Technology

2015-03-01

in the framework of probabilistic finite state automata (PFSA) and language measure from a control-theoretic perspective. The proposed concept has been...DOI: 10.1115/1.4027876] Keywords: path planning, language measure, probabilistic finite state automata 1 Motivation and Introduction In general

The impact of uncertain threat on affective bias: Individual differences in response to ambiguity.

PubMed

Neta, Maital; Cantelon, Julie; Haga, Zachary; Mahoney, Caroline R; Taylor, Holly A; Davis, F Caroline

2017-12-01

Individuals who operate under highly stressful conditions (e.g., military personnel and first responders) are often faced with the challenge of quickly interpreting ambiguous information in uncertain and threatening environments. When faced with ambiguity, it is likely adaptive to view potentially dangerous stimuli as threatening until contextual information proves otherwise. One laboratory-based paradigm that can be used to simulate uncertain threat is known as threat of shock (TOS), in which participants are told that they might receive mild but unpredictable electric shocks while performing an unrelated task. The uncertainty associated with this potential threat induces a state of emotional arousal that is not overwhelmingly stressful, but has widespread-both adaptive and maladaptive-effects on cognitive and affective function. For example, TOS is thought to enhance aversive processing and abolish positivity bias. Importantly, in certain situations (e.g., when walking home alone at night), this anxiety can promote an adaptive state of heightened vigilance and defense mobilization. In the present study, we used TOS to examine the effects of uncertain threat on valence bias, or the tendency to interpret ambiguous social cues as positive or negative. As predicted, we found that heightened emotional arousal elicited by TOS was associated with an increased tendency to interpret ambiguous cues negatively. Such negative interpretations are likely adaptive in situations in which threat detection is critical for survival and should override an individual's tendency to interpret ambiguity positively in safe contexts. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

State-dependent resource harvesting with lagged information about system states

USGS Publications Warehouse

Johnson, Fred A.; Fackler, Paul L.; Boomer, G Scott; Zimmerman, Guthrie S.; Williams, Byron K.; Nichols, James D.; Dorazio, Robert

2016-01-01

Markov decision processes (MDPs), which involve a temporal sequence of actions conditioned on the state of the managed system, are increasingly being applied in natural resource management. This study focuses on the modification of a traditional MDP to account for those cases in which an action must be chosen after a significant time lag in observing system state, but just prior to a new observation. In order to calculate an optimal decision policy under these conditions, possible actions must be conditioned on the previous observed system state and action taken. We show how to solve these problems when the state transition structure is known and when it is uncertain. Our focus is on the latter case, and we show how actions must be conditioned not only on the previous system state and action, but on the probabilities associated with alternative models of system dynamics. To demonstrate this framework, we calculated and simulated optimal, adaptive policies for MDPs with lagged states for the problem of deciding annual harvest regulations for mallards (Anas platyrhynchos) in the United States. In this particular example, changes in harvest policy induced by the use of lagged information about system state were sufficient to maintain expected management performance (e.g. population size, harvest) even in the face of an uncertain system state at the time of a decision.

Correlates of vulnerability in Chiricahua fox squirrels

Treesearch

Bret S. Pasch; John L. Koprowski

2005-01-01

Chiricahua fox squirrels (Sciurus nayaritensis chiricahuae) are endemic to the Chiricahua Mountains of southeastern Arizona. A paucity of natural history information and uncertain conservation status served as impetus for us to initiate a descriptive ecological study of the species. We examined reproductive and population ecology of Chiricahua fox...

Stochastic Modeling of Laminar-Turbulent Transition

NASA Technical Reports Server (NTRS)

Rubinstein, Robert; Choudhari, Meelan

2002-01-01

Stochastic versions of stability equations are developed in order to develop integrated models of transition and turbulence and to understand the effects of uncertain initial conditions on disturbance growth. Stochastic forms of the resonant triad equations, a high Reynolds number asymptotic theory, and the parabolized stability equations are developed.

Issues in Financing School-Based Health Centers: A Guide for State Officials.

ERIC Educational Resources Information Center

George Washington Univ., Washington, DC.

Despite the recent, unprecedented growth of school-based health centers and the related increased support from state government, the future of school-based health centers is uncertain. Since they can no longer rely on federal support, private insurance, or other commercial sources, each state must develop its own approach to supporting the…

Secure estimation, control and optimization of uncertain cyber-physical systems with applications to power networks

NASA Astrophysics Data System (ADS)

Taha, Ahmad Fayez

Transportation networks, wearable devices, energy systems, and the book you are reading now are all ubiquitous cyber-physical systems (CPS). These inherently uncertain systems combine physical phenomena with communication, data processing, control and optimization. Many CPSs are controlled and monitored by real-time control systems that use communication networks to transmit and receive data from systems modeled by physical processes. Existing studies have addressed a breadth of challenges related to the design of CPSs. However, there is a lack of studies on uncertain CPSs subject to dynamic unknown inputs and cyber-attacks---an artifact of the insertion of communication networks and the growing complexity of CPSs. The objective of this dissertation is to create secure, computational foundations for uncertain CPSs by establishing a framework to control, estimate and optimize the operation of these systems. With major emphasis on power networks, the dissertation deals with the design of secure computational methods for uncertain CPSs, focusing on three crucial issues---(1) cyber-security and risk-mitigation, (2) network-induced time-delays and perturbations and (3) the encompassed extreme time-scales. The dissertation consists of four parts. In the first part, we investigate dynamic state estimation (DSE) methods and rigorously examine the strengths and weaknesses of the proposed routines under dynamic attack-vectors and unknown inputs. In the second part, and utilizing high-frequency measurements in smart grids and the developed DSE methods in the first part, we present a risk mitigation strategy that minimizes the encountered threat levels, while ensuring the continual observability of the system through available, safe measurements. The developed methods in the first two parts rely on the assumption that the uncertain CPS is not experiencing time-delays, an assumption that might fail under certain conditions. To overcome this challenge, networked unknown input observers---observers/estimators for uncertain CPSs---are designed such that the effect of time-delays and cyber-induced perturbations are minimized, enabling secure DSE and risk mitigation in the first two parts. The final part deals with the extreme time-scales encompassed in CPSs, generally, and smart grids, specifically. Operational decisions for long time-scales can adversely affect the security of CPSs for faster time-scales. We present a model that jointly describes steady-state operation and transient stability by combining convex optimal power flow with semidefinite programming formulations of an optimal control problem. This approach can be jointly utilized with the aforementioned parts of the dissertation work, considering time-delays and DSE. The research contributions of this dissertation furnish CPS stakeholders with insights on the design and operation of uncertain CPSs, whilst guaranteeing the system's real-time safety. Finally, although many of the results of this dissertation are tailored to power systems, the results are general enough to be applied for a variety of uncertain CPSs.

Physical examination prior to initiating hormonal contraception: a systematic review.

PubMed

Tepper, Naomi K; Curtis, Kathryn M; Steenland, Maria W; Marchbanks, Polly A

2013-05-01

Provision of contraception is often linked with physical examination, including clinical breast examination (CBE) and pelvic examination. This review was conducted to evaluate the evidence regarding outcomes among women with and without physical examination prior to initiating hormonal contraceptives. The PubMed database was searched from database inception through March 2012 for all peer-reviewed articles in any language concerning CBE and pelvic examination prior to initiating hormonal contraceptives. The quality of each study was assessed using the United States Preventive Services Task Force grading system. The search did not identify any evidence regarding outcomes among women screened versus not screened with CBE prior to initiation of hormonal contraceptives. The search identified two case-control studies of fair quality which compared women who did or did not undergo pelvic examination prior to initiating oral contraceptives (OCs) or depot medroxyprogesterone acetate (DMPA). No differences in risk factors for cervical neoplasia, incidence of sexually transmitted infections, incidence of abnormal Pap smears or incidence of abnormal wet mount findings were observed. Although women with breast cancer should not use hormonal contraceptives, there is little utility in screening prior to initiation, due to the low incidence of breast cancer and uncertain value of CBE among women of reproductive age. Two fair quality studies demonstrated no differences between women who did or did not undergo pelvic examination prior to initiating OCs or DMPA with respect to risk factors or clinical outcomes. In addition, pelvic examination is not likely to detect any conditions for which hormonal contraceptives would be unsafe. Published by Elsevier Inc.

Controllable uncertain opinion diffusion under confidence bound and unpredicted diffusion probability

NASA Astrophysics Data System (ADS)

Yan, Fuhan; Li, Zhaofeng; Jiang, Yichuan

2016-05-01

The issues of modeling and analyzing diffusion in social networks have been extensively studied in the last few decades. Recently, many studies focus on uncertain diffusion process. The uncertainty of diffusion process means that the diffusion probability is unpredicted because of some complex factors. For instance, the variety of individuals' opinions is an important factor that can cause uncertainty of diffusion probability. In detail, the difference between opinions can influence the diffusion probability, and then the evolution of opinions will cause the uncertainty of diffusion probability. It is known that controlling the diffusion process is important in the context of viral marketing and political propaganda. However, previous methods are hardly feasible to control the uncertain diffusion process of individual opinion. In this paper, we present suitable strategy to control this diffusion process based on the approximate estimation of the uncertain factors. We formulate a model in which the diffusion probability is influenced by the distance between opinions, and briefly discuss the properties of the diffusion model. Then, we present an optimization problem at the background of voting to show how to control this uncertain diffusion process. In detail, it is assumed that each individual can choose one of the two candidates or abstention based on his/her opinion. Then, we present strategy to set suitable initiators and their opinions so that the advantage of one candidate will be maximized at the end of diffusion. The results show that traditional influence maximization algorithms are not applicable to this problem, and our algorithm can achieve expected performance.

Estimation for the Linear Model With Uncertain Covariance Matrices

NASA Astrophysics Data System (ADS)

Zachariah, Dave; Shariati, Nafiseh; Bengtsson, Mats; Jansson, Magnus; Chatterjee, Saikat

2014-03-01

We derive a maximum a posteriori estimator for the linear observation model, where the signal and noise covariance matrices are both uncertain. The uncertainties are treated probabilistically by modeling the covariance matrices with prior inverse-Wishart distributions. The nonconvex problem of jointly estimating the signal of interest and the covariance matrices is tackled by a computationally efficient fixed-point iteration as well as an approximate variational Bayes solution. The statistical performance of estimators is compared numerically to state-of-the-art estimators from the literature and shown to perform favorably.

Has Lean improved organizational decision making?

PubMed

Simons, Pascale; Benders, Jos; Bergs, Jochen; Marneffe, Wim; Vandijck, Dominique

2016-06-13

Purpose - Sustainable improvement is likely to be hampered by ambiguous objectives and uncertain cause-effect relations in care processes (the organization's decision-making context). Lean management can improve implementation results because it decreases ambiguity and uncertainties. But does it succeed? Many quality improvement (QI) initiatives are appropriate improvement strategies in organizational contexts characterized by low ambiguity and uncertainty. However, most care settings do not fit this context. The purpose of this paper is to investigate whether a Lean-inspired change program changed the organization's decision-making context, making it more amenable for QI initiatives. Design/methodology/approach - In 2014, 12 professionals from a Dutch radiotherapy institute were interviewed regarding their perceptions of a Lean program in their organization and the perceived ambiguous objectives and uncertain cause-effect relations in their clinical processes. A survey (25 questions), addressing the same concepts, was conducted among the interviewees in 2011 and 2014. The structured interviews were analyzed using a deductive approach. Quantitative data were analyzed using appropriate statistics. Findings - Interviewees experienced improved shared visions and the number of uncertain cause-effect relations decreased. Overall, more positive (99) than negative Lean effects (18) were expressed. The surveys revealed enhanced process predictability and standardization, and improved shared visions. Practical implications - Lean implementation has shown to lead to greater transparency and increased shared visions. Originality/value - Lean management decreased ambiguous objectives and reduced uncertainties in clinical process cause-effect relations. Therefore, decision making benefitted from Lean increasing QI's sustainability.

Interpreting energy scenarios

NASA Astrophysics Data System (ADS)

Iyer, Gokul; Edmonds, James

2018-05-01

Quantitative scenarios from energy-economic models inform decision-making about uncertain futures. Now, research shows the different ways these scenarios are subsequently used by users not involved in their initial development. In the absence of clear guidance from modellers, users may place too much or too little confidence in scenario assumptions and results.

Modeled Watershed Runoff Associated with Variations in Precipitation Data, with Implications for Contaminant Fluxes: Initial Results

EPA Science Inventory

Precipitation is one of the primary forcing functions of hydrologic and watershed fate and transport models; however, in light of advances in precipitation estimates across watersheds, data remain highly uncertain. A wide variety of simulated and observed precipitation data are a...

Nuclear modification factor in an anisotropic quark-gluon plasma

NASA Astrophysics Data System (ADS)

Mandal, Mahatsab; Bhattacharya, Lusaka; Roy, Pradip

2011-10-01

We calculate the nuclear modification factor (RAA) of light hadrons by taking into account the initial state momentum anisotropy of the quark-gluon plasma (QGP) expected to be formed in relativistic heavy ion collisions. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter. A phenomenological model for the space-time evolution of the anisotropic QGP is used to obtain the time dependence of the anisotropy parameter ξ and the hard momentum scale, phard. The result is then compared with the PHENIX experimental data to constrain the isotropization time scale, τiso for fixed initial conditions (FIC). It is shown that the extracted value of τiso lies in the range 0.5⩽τiso⩽1.5. However, using a fixed final multiplicity (FFM) condition does not lead to any firm conclusion about the extraction of the isotropization time. The present calculation is also extended to contrast with the recent measurement of nuclear modification factor by the ALICE collaboration at s=2.76 TeV. It is argued that in the present approach, the extraction of τiso at this energy is uncertain and, therefore, refinement of the model is necessary. The sensitivity of the results on the initial conditions has been discussed. We also present the nuclear modification factor at Large Hadron Collider (LHC) energies with s=5.5 TeV.

Cooperative learning neural network output feedback control of uncertain nonlinear multi-agent systems under directed topologies

NASA Astrophysics Data System (ADS)

Wang, W.; Wang, D.; Peng, Z. H.

2017-09-01

Without assuming that the communication topologies among the neural network (NN) weights are to be undirected and the states of each agent are measurable, the cooperative learning NN output feedback control is addressed for uncertain nonlinear multi-agent systems with identical structures in strict-feedback form. By establishing directed communication topologies among NN weights to share their learned knowledge, NNs with cooperative learning laws are employed to identify the uncertainties. By designing NN-based κ-filter observers to estimate the unmeasurable states, a new cooperative learning output feedback control scheme is proposed to guarantee that the system outputs can track nonidentical reference signals with bounded tracking errors. A simulation example is given to demonstrate the effectiveness of the theoretical results.

Switching State-Feedback LPV Control with Uncertain Scheduling Parameters

NASA Technical Reports Server (NTRS)

He, Tianyi; Al-Jiboory, Ali Khudhair; Swei, Sean Shan-Min; Zhu, Guoming G.

2017-01-01

This paper presents a new method to design Robust Switching State-Feedback Gain-Scheduling (RSSFGS) controllers for Linear Parameter Varying (LPV) systems with uncertain scheduling parameters. The domain of scheduling parameters are divided into several overlapped subregions to undergo hysteresis switching among a family of simultaneously designed LPV controllers over the corresponding subregion with the guaranteed H-infinity performance. The synthesis conditions are given in terms of Parameterized Linear Matrix Inequalities that guarantee both stability and performance at each subregion and associated switching surfaces. The switching stability is ensured by descent parameter-dependent Lyapunov function on switching surfaces. By solving the optimization problem, RSSFGS controller can be obtained for each subregion. A numerical example is given to illustrate the effectiveness of the proposed approach over the non-switching controllers.

Regional and national significance of biological nitrogen fixation by crops in the United States

EPA Science Inventory

Background/Questions/Methods Biological nitrogen fixation by crops (C-BNF) represents one of the largest anthropogenic inputs of reactive nitrogen (N) to land surfaces around the world. In the United States (US), existing estimates of C-BNF are uncertain because of incomplete o...

Mesoscale Predictability and Error Growth in Short Range Ensemble Forecasts

NASA Astrophysics Data System (ADS)

Gingrich, Mark

Although it was originally suggested that small-scale, unresolved errors corrupt forecasts at all scales through an inverse error cascade, some authors have proposed that those mesoscale circulations resulting from stationary forcing on the larger scale may inherit the predictability of the large-scale motions. Further, the relative contributions of large- and small-scale uncertainties in producing error growth in the mesoscales remain largely unknown. Here, 100 member ensemble forecasts are initialized from an ensemble Kalman filter (EnKF) to simulate two winter storms impacting the East Coast of the United States in 2010. Four verification metrics are considered: the local snow water equivalence, total liquid water, and 850 hPa temperatures representing mesoscale features; and the sea level pressure field representing a synoptic feature. It is found that while the predictability of the mesoscale features can be tied to the synoptic forecast, significant uncertainty existed on the synoptic scale at lead times as short as 18 hours. Therefore, mesoscale details remained uncertain in both storms due to uncertainties at the large scale. Additionally, the ensemble perturbation kinetic energy did not show an appreciable upscale propagation of error for either case. Instead, the initial condition perturbations from the cycling EnKF were maximized at large scales and immediately amplified at all scales without requiring initial upscale propagation. This suggests that relatively small errors in the synoptic-scale initialization may have more importance in limiting predictability than errors in the unresolved, small-scale initial conditions.

Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters

PubMed Central

Liu, Fei; Heiner, Monika; Yang, Ming

2016-01-01

Stochastic Petri nets (SPNs) have been widely used to model randomness which is an inherent feature of biological systems. However, for many biological systems, some kinetic parameters may be uncertain due to incomplete, vague or missing kinetic data (often called fuzzy uncertainty), or naturally vary, e.g., between different individuals, experimental conditions, etc. (often called variability), which has prevented a wider application of SPNs that require accurate parameters. Considering the strength of fuzzy sets to deal with uncertain information, we apply a specific type of stochastic Petri nets, fuzzy stochastic Petri nets (FSPNs), to model and analyze biological systems with uncertain kinetic parameters. FSPNs combine SPNs and fuzzy sets, thereby taking into account both randomness and fuzziness of biological systems. For a biological system, SPNs model the randomness, while fuzzy sets model kinetic parameters with fuzzy uncertainty or variability by associating each parameter with a fuzzy number instead of a crisp real value. We introduce a simulation-based analysis method for FSPNs to explore the uncertainties of outputs resulting from the uncertainties associated with input parameters, which works equally well for bounded and unbounded models. We illustrate our approach using a yeast polarization model having an infinite state space, which shows the appropriateness of FSPNs in combination with simulation-based analysis for modeling and analyzing biological systems with uncertain information. PMID:26910830

Neural-network-based online HJB solution for optimal robust guaranteed cost control of continuous-time uncertain nonlinear systems.

PubMed

Liu, Derong; Wang, Ding; Wang, Fei-Yue; Li, Hongliang; Yang, Xiong

2014-12-01

In this paper, the infinite horizon optimal robust guaranteed cost control of continuous-time uncertain nonlinear systems is investigated using neural-network-based online solution of Hamilton-Jacobi-Bellman (HJB) equation. By establishing an appropriate bounded function and defining a modified cost function, the optimal robust guaranteed cost control problem is transformed into an optimal control problem. It can be observed that the optimal cost function of the nominal system is nothing but the optimal guaranteed cost of the original uncertain system. A critic neural network is constructed to facilitate the solution of the modified HJB equation corresponding to the nominal system. More importantly, an additional stabilizing term is introduced for helping to verify the stability, which reinforces the updating process of the weight vector and reduces the requirement of an initial stabilizing control. The uniform ultimate boundedness of the closed-loop system is analyzed by using the Lyapunov approach as well. Two simulation examples are provided to verify the effectiveness of the present control approach.

NegBio: a high-performance tool for negation and uncertainty detection in radiology reports.

PubMed

Peng, Yifan; Wang, Xiaosong; Lu, Le; Bagheri, Mohammadhadi; Summers, Ronald; Lu, Zhiyong

2018-01-01

Negative and uncertain medical findings are frequent in radiology reports, but discriminating them from positive findings remains challenging for information extraction. Here, we propose a new algorithm, NegBio, to detect negative and uncertain findings in radiology reports. Unlike previous rule-based methods, NegBio utilizes patterns on universal dependencies to identify the scope of triggers that are indicative of negation or uncertainty. We evaluated NegBio on four datasets, including two public benchmarking corpora of radiology reports, a new radiology corpus that we annotated for this work, and a public corpus of general clinical texts. Evaluation on these datasets demonstrates that NegBio is highly accurate for detecting negative and uncertain findings and compares favorably to a widely-used state-of-the-art system NegEx (an average of 9.5% improvement in precision and 5.1% in F1-score). https://github.com/ncbi-nlp/NegBio.

Adaptive fuzzy predictive sliding control of uncertain nonlinear systems with bound-known input delay.

PubMed

Khazaee, Mostafa; Markazi, Amir H D; Omidi, Ehsan

2015-11-01

In this paper, a new Adaptive Fuzzy Predictive Sliding Mode Control (AFP-SMC) is presented for nonlinear systems with uncertain dynamics and unknown input delay. The control unit consists of a fuzzy inference system to approximate the ideal linearization control, together with a switching strategy to compensate for the estimation errors. Also, an adaptive fuzzy predictor is used to estimate the future values of the system states to compensate for the time delay. The adaptation laws are used to tune the controller and predictor parameters, which guarantee the stability based on a Lyapunov-Krasovskii functional. To evaluate the method effectiveness, the simulation and experiment on an overhead crane system are presented. According to the obtained results, AFP-SMC can effectively control the uncertain nonlinear systems, subject to input delays of known bound. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive output feedback control of uncertain nonlinear systems using single-hidden-layer neural networks.

PubMed

Hovakimyan, N; Nardi, F; Calise, A; Kim, Nakwan

2002-01-01

We consider adaptive output feedback control of uncertain nonlinear systems, in which both the dynamics and the dimension of the regulated system may be unknown. However, the relative degree of the regulated output is assumed to be known. Given a smooth reference trajectory, the problem is to design a controller that forces the system measurement to track it with bounded errors. The classical approach requires a state observer. Finding a good observer for an uncertain nonlinear system is not an obvious task. We argue that it is sufficient to build an observer for the output tracking error. Ultimate boundedness of the error signals is shown through Lyapunov's direct method. The theoretical results are illustrated in the design of a controller for a fourth-order nonlinear system of relative degree two and a high-bandwidth attitude command system for a model R-50 helicopter.

Record-Breaking Early Flowering in the Eastern United States

PubMed Central

Ellwood, Elizabeth R.; Temple, Stanley A.; Primack, Richard B.; Davis, Charles C.

2013-01-01

Flowering times are well-documented indicators of the ecological effects of climate change and are linked to numerous ecosystem processes and trophic interactions. Dozens of studies have shown that flowering times for many spring-flowering plants have become earlier as a result of recent climate change, but it is uncertain if flowering times will continue to advance as temperatures rise. Here, we used long-term flowering records initiated by Henry David Thoreau in 1852 and Aldo Leopold in 1935 to investigate this question. Our analyses demonstrate that record-breaking spring temperatures in 2010 and 2012 in Massachusetts, USA, and 2012 in Wisconsin, USA, resulted in the earliest flowering times in recorded history for dozens of spring-flowering plants of the eastern United States. These dramatic advances in spring flowering were successfully predicted by historical relationships between flowering and spring temperature spanning up to 161 years of ecological change. These results demonstrate that numerous temperate plant species have yet to show obvious signs of physiological constraints on phenological advancement in the face of climate change. PMID:23342001

Capture-recapture methodology

USGS Publications Warehouse

Gould, William R.; Kendall, William L.

2013-01-01

Capture-recapture methods were initially developed to estimate human population abundance, but since that time have seen widespread use for fish and wildlife populations to estimate and model various parameters of population, metapopulation, and disease dynamics. Repeated sampling of marked animals provides information for estimating abundance and tracking the fate of individuals in the face of imperfect detection. Mark types have evolved from clipping or tagging to use of noninvasive methods such as photography of natural markings and DNA collection from feces. Survival estimation has been emphasized more recently as have transition probabilities between life history states and/or geographical locations, even where some states are unobservable or uncertain. Sophisticated software has been developed to handle highly parameterized models, including environmental and individual covariates, to conduct model selection, and to employ various estimation approaches such as maximum likelihood and Bayesian approaches. With these user-friendly tools, complex statistical models for studying population dynamics have been made available to ecologists. The future will include a continuing trend toward integrating data types, both for tagged and untagged individuals, to produce more precise and robust population models.

Integrating Health into Local Climate Response: Lessons from the U.S. CDC Climate-Ready States and Cities Initiative

PubMed Central

Fox, Mary A.; Kaye, Charlotte; Resnick, Beth

2017-01-01

Summary: Public health has potential to serve as a frame to convey the urgency of behavior change needed to adapt to a changing climate and reduce greenhouse gas emissions. Local governments form the backbone of climate-related public health preparedness. Yet local health agencies are often inadequately prepared and poorly integrated into climate change assessments and plans. We reviewed the climate health profiles of 16 states and two cities participating in the U.S. Centers for Disease Control and Prevention (CDC)’s Climate-Ready States and Cities Initiative (CRSCI) that aims to build local capacity to assess and respond to the health impacts of climate change. Following recommendations from a recent expert panel strategic review, we present illustrations of emerging promising practice and future directions. We found that CRSCI has strengthened climate preparedness and response in local public health agencies by identifying critical climate-health impacts and vulnerable populations, and has helped integrate health more fully into broader climate planning. Promising practice was found in all three recommendation areas identified by the expert panel (leveraging partnerships, refining assessment methodologies and enhancing communications), particularly with regard to health impacts of extreme heat. Vast needs remain, however, suggesting the need to disseminate CRSCI experience to non-grantees. In conclusion, the CRSCI program approach and selected activities illustrate a way forward toward robust, targeted local preparedness and response that may serve as a useful example for public health departments in the United States and internationally, particularly at a time of uncertain commitment to climate change agreements at the national level. https://doi.org/10.1289/EHP1838 PMID:28934724

Delays and Uncertain Energy Savings in Program to Promote State Energy Conservation. Report to the Congress by the Comptroller General of the United States.

ERIC Educational Resources Information Center

Comptroller General of the U.S., Washington, DC.

Presented is a study and assessment of the United States Department of Energy State Energy Conservation Program (SECP). The goal of the SECP is to reduce energy consumption in each state by 5% by 1980. However, it is unlikely that this goal will be attained or that the savings reported for 1978 are a valid measure of the program's impact on energy…

An optimization approach for observation association with systemic uncertainty applied to electro-optical systems

NASA Astrophysics Data System (ADS)

Worthy, Johnny L.; Holzinger, Marcus J.; Scheeres, Daniel J.

2018-06-01

The observation to observation measurement association problem for dynamical systems can be addressed by determining if the uncertain admissible regions produced from each observation have one or more points of intersection in state space. An observation association method is developed which uses an optimization based approach to identify local Mahalanobis distance minima in state space between two uncertain admissible regions. A binary hypothesis test with a selected false alarm rate is used to assess the probability that an intersection exists at the point(s) of minimum distance. The systemic uncertainties, such as measurement uncertainties, timing errors, and other parameter errors, define a distribution about a state estimate located at the local Mahalanobis distance minima. If local minima do not exist, then the observations are not associated. The proposed method utilizes an optimization approach defined on a reduced dimension state space to reduce the computational load of the algorithm. The efficacy and efficiency of the proposed method is demonstrated on observation data collected from the Georgia Tech Space Object Research Telescope.

Quantum uncertainty switches on or off the error-disturbance tradeoff

NASA Astrophysics Data System (ADS)

Zhang, Yu-Xiang; Su, Zu-En; Zhu, Xuanmin; Wu, Shengjun; Chen, Zeng-Bing

2016-06-01

The indeterminacy of quantum mechanics was originally presented by Heisenberg through the tradeoff between the measuring error of the observable A and the consequential disturbance to the value of another observable B. This tradeoff now has become a popular interpretation of the uncertainty principle. However, the historic idea has never been exactly formulated previously and is recently called into question. A theory built upon operational and state-relevant definitions of error and disturbance is called for to rigorously reexamine the relationship. Here by putting forward such natural definitions, we demonstrate both theoretically and experimentally that there is no tradeoff if the outcome of measuring B is more uncertain than that of A. Otherwise, the tradeoff will be switched on and well characterized by the Jensen-Shannon divergence. Our results reveal the hidden effect of the uncertain nature possessed by the measured state, and conclude that the state-relevant relation between error and disturbance is not almosteverywhere a tradeoff as people usually believe.

Honey bees (Hymenoptera: Apidae) of African origin exist in non-africanized areas of the southern United States: evidence from mitochondrial DNA

Treesearch

M.A. Pinto; W.S. Sheppard; J.S. Johnston; W.L. Rubink; R.N. Coulson; N.M. Schiff; I. Kandemir; J.C. Patton

2007-01-01

Descendents of Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) (the Africanized honey bee) arrived in the United States in 1990. Whether this was the first introduction is uncertain. A survey of feral honey bees from non-Africanized areas of the southern United States revealed three colonies (from Georgia, Texas, and New Mexico) with a...

Formal Consistency Verification of Deliberative Agents with Respect to Communication Protocols

NASA Technical Reports Server (NTRS)

Ramirez, Jaime; deAntonio, Angelica

2004-01-01

The aim of this paper is to show a method that is able to detect inconsistencies in the reasoning carried out by a deliberative agent. The agent is supposed to be provided with a hybrid Knowledge Base expressed in a language called CCR-2, based on production rules and hierarchies of frames, which permits the representation of non-monotonic reasoning, uncertain reasoning and arithmetic constraints in the rules. The method can give a specification of the scenarios in which the agent would deduce an inconsistency. We define a scenario to be a description of the initial agent s state (in the agent life cycle), a deductive tree of rule firings, and a partially ordered set of messages and/or stimuli that the agent must receive from other agents and/or the environment. Moreover, the method will make sure that the scenarios will be valid w.r.t. the communication protocols in which the agent is involved.

Novel framework for assessing epidemiologic effects of influenza epidemics and pandemics.

PubMed

Reed, Carrie; Biggerstaff, Matthew; Finelli, Lyn; Koonin, Lisa M; Beauvais, Denise; Uzicanin, Amra; Plummer, Andrew; Bresee, Joe; Redd, Stephen C; Jernigan, Daniel B

2013-01-01

The effects of influenza on a population are attributable to the clinical severity of illness and the number of persons infected, which can vary greatly between seasons or pandemics. To create a systematic framework for assessing the public health effects of an emerging pandemic, we reviewed data from past influenza seasons and pandemics to characterize severity and transmissibility (based on ranges of these measures in the United States) and outlined a formal assessment of the potential effects of a novel virus. The assessment was divided into 2 periods. Because early in a pandemic, measurement of severity and transmissibility is uncertain, we used a broad dichotomous scale in the initial assessment to divide the range of historic values. In the refined assessment, as more data became available, we categorized those values more precisely. By organizing and prioritizing data collection, this approach may inform an evidence-based assessment of pandemic effects and guide decision making.

Novel Framework for Assessing Epidemiologic Effects of Influenza Epidemics and Pandemics

PubMed Central

Biggerstaff, Matthew; Finelli, Lyn; Koonin, Lisa M.; Beauvais, Denise; Uzicanin, Amra; Plummer, Andrew; Bresee, Joe; Redd, Stephen C.; Jernigan, Daniel B.

2013-01-01

The effects of influenza on a population are attributable to the clinical severity of illness and the number of persons infected, which can vary greatly between seasons or pandemics. To create a systematic framework for assessing the public health effects of an emerging pandemic, we reviewed data from past influenza seasons and pandemics to characterize severity and transmissibility (based on ranges of these measures in the United States) and outlined a formal assessment of the potential effects of a novel virus. The assessment was divided into 2 periods. Because early in a pandemic, measurement of severity and transmissibility is uncertain, we used a broad dichotomous scale in the initial assessment to divide the range of historic values. In the refined assessment, as more data became available, we categorized those values more precisely. By organizing and prioritizing data collection, this approach may inform an evidence-based assessment of pandemic effects and guide decision making. PMID:23260039

Composite Robust $$H_\\infty$$ Control for Uncertain Stochastic Nonlinear Systems with State Delay via Disturbance Observer

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

Liu, Yunlong; Wang, Hong; Guo, Lei

Here in this note, the robust stochastic stabilization and robust H_infinity control problems are investigated for uncertain stochastic time-delay systems with nonlinearity and multiple disturbances. By estimating the disturbance, which can be described by an exogenous model, a composite hierarchical control scheme is proposed that integrates the output of the disturbance observer with state feedback control law. Sufficient conditions for the existence of the disturbance observer and composite hierarchical controller are established in terms of linear matrix inequalities, which ensure the mean-square asymptotic stability of the resulting closed-loop system and the disturbance attenuation. It has been shown that the disturbancemore » rejection performance can also be achieved. A numerical example is provided to show the potential of the proposed techniques and encouraging results have been obtained.« less

Robust decentralised stabilisation of uncertain large-scale interconnected nonlinear descriptor systems via proportional plus derivative feedback

NASA Astrophysics Data System (ADS)

Li, Jian; Zhang, Qingling; Ren, Junchao; Zhang, Yanhao

2017-10-01

This paper studies the problem of robust stability and stabilisation for uncertain large-scale interconnected nonlinear descriptor systems via proportional plus derivative state feedback or proportional plus derivative output feedback. The basic idea of this work is to use the well-known differential mean value theorem to deal with the nonlinear model such that the considered nonlinear descriptor systems can be transformed into linear parameter varying systems. By using a parameter-dependent Lyapunov function, a decentralised proportional plus derivative state feedback controller and decentralised proportional plus derivative output feedback controller are designed, respectively such that the closed-loop system is quadratically normal and quadratically stable. Finally, a hypersonic vehicle practical simulation example and numerical example are given to illustrate the effectiveness of the results obtained in this paper.

Global tracking for a class of uncertain nonlinear systems with unknown sign-switching control direction by output feedback

NASA Astrophysics Data System (ADS)

Roux Oliveira, Tiago; Jacoud Peixoto, Alessandro; Hsu, Liu

2015-09-01

This paper addresses the design of a sliding mode controller for a class of high-order uncertain nonlinear plants with unmatched state-dependent nonlinearities and unknown sign of the high frequency gain, i.e., the control direction is assumed unknown. Differently from most previous studies, the control direction is allowed to switch its sign. We show that it is possible to obtain global exact tracking using only output-feedback by coupling a relay periodic switching function with a norm state observer. One significant advantage of the new scheme is its robustness and improved transient response under arbitrary changes of the control direction which have been theoretically demonstrated for jump variations and successfully tested by simulations. The proposed controller is also evaluated with a DC motor control experiment.

Composite Robust $$H_\\infty$$ Control for Uncertain Stochastic Nonlinear Systems with State Delay via Disturbance Observer

DOE PAGES

Liu, Yunlong; Wang, Hong; Guo, Lei

2018-03-26

Here in this note, the robust stochastic stabilization and robust H_infinity control problems are investigated for uncertain stochastic time-delay systems with nonlinearity and multiple disturbances. By estimating the disturbance, which can be described by an exogenous model, a composite hierarchical control scheme is proposed that integrates the output of the disturbance observer with state feedback control law. Sufficient conditions for the existence of the disturbance observer and composite hierarchical controller are established in terms of linear matrix inequalities, which ensure the mean-square asymptotic stability of the resulting closed-loop system and the disturbance attenuation. It has been shown that the disturbancemore » rejection performance can also be achieved. A numerical example is provided to show the potential of the proposed techniques and encouraging results have been obtained.« less

Particle filter based hybrid prognostics for health monitoring of uncertain systems in bond graph framework

NASA Astrophysics Data System (ADS)

Jha, Mayank Shekhar; Dauphin-Tanguy, G.; Ould-Bouamama, B.

2016-06-01

The paper's main objective is to address the problem of health monitoring of system parameters in Bond Graph (BG) modeling framework, by exploiting its structural and causal properties. The system in feedback control loop is considered uncertain globally. Parametric uncertainty is modeled in interval form. The system parameter is undergoing degradation (prognostic candidate) and its degradation model is assumed to be known a priori. The detection of degradation commencement is done in a passive manner which involves interval valued robust adaptive thresholds over the nominal part of the uncertain BG-derived interval valued analytical redundancy relations (I-ARRs). The latter forms an efficient diagnostic module. The prognostics problem is cast as joint state-parameter estimation problem, a hybrid prognostic approach, wherein the fault model is constructed by considering the statistical degradation model of the system parameter (prognostic candidate). The observation equation is constructed from nominal part of the I-ARR. Using particle filter (PF) algorithms; the estimation of state of health (state of prognostic candidate) and associated hidden time-varying degradation progression parameters is achieved in probabilistic terms. A simplified variance adaptation scheme is proposed. Associated uncertainties which arise out of noisy measurements, parametric degradation process, environmental conditions etc. are effectively managed by PF. This allows the production of effective predictions of the remaining useful life of the prognostic candidate with suitable confidence bounds. The effectiveness of the novel methodology is demonstrated through simulations and experiments on a mechatronic system.

Geostatistics and Bayesian updating for transmissivity estimation in a multiaquifer system in Manitoba, Canada.

PubMed

Kennedy, Paula L; Woodbury, Allan D

2002-01-01

In ground water flow and transport modeling, the heterogeneous nature of porous media has a considerable effect on the resulting flow and solute transport. Some method of generating the heterogeneous field from a limited dataset of uncertain measurements is required. Bayesian updating is one method that interpolates from an uncertain dataset using the statistics of the underlying probability distribution function. In this paper, Bayesian updating was used to determine the heterogeneous natural log transmissivity field for a carbonate and a sandstone aquifer in southern Manitoba. It was determined that the transmissivity in m2/sec followed a natural log normal distribution for both aquifers with a mean of -7.2 and - 8.0 for the carbonate and sandstone aquifers, respectively. The variograms were calculated using an estimator developed by Li and Lake (1994). Fractal nature was not evident in the variogram from either aquifer. The Bayesian updating heterogeneous field provided good results even in cases where little data was available. A large transmissivity zone in the sandstone aquifer was created by the Bayesian procedure, which is not a reflection of any deterministic consideration, but is a natural outcome of updating a prior probability distribution function with observations. The statistical model returns a result that is very reasonable; that is homogeneous in regions where little or no information is available to alter an initial state. No long range correlation trends or fractal behavior of the log-transmissivity field was observed in either aquifer over a distance of about 300 km.

A Probabilistic Asteroid Impact Risk Model

NASA Technical Reports Server (NTRS)

Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

2016-01-01

Asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data has little effect on the metrics of interest.

Anxiety associated with diagnostic uncertainty in early pregnancy.

PubMed

Richardson, A; Raine-Fenning, N; Deb, S; Campbell, B; Vedhara, K

2017-08-01

To determine anxiety levels of women presenting to an early pregnancy assessment unit (EPAU) with abdominal pain and/or vaginal bleeding and to assess how these levels change over time and according to ultrasonographic diagnosis. We undertook a prospective cohort study in an EPAU in a large UK teaching hospital. Women with abdominal pain and/or vaginal bleeding in early pregnancy (< 12 weeks' gestation) presenting for the first time were eligible for inclusion in the study. State anxiety levels were assessed using the standardized short form of Spielberger's state-trait anxiety inventory (STAI) on three occasions (before, immediately after and 48-72 hours after an ultrasound scan). Scores were correlated with ultrasonographic diagnosis. The diagnosis was either certain or uncertain. Certain diagnoses were either positive, i.e. a viable intrauterine pregnancy (IUP), or negative, i.e. a non-viable IUP or ectopic pregnancy. Uncertain diagnoses included pregnancy of unknown location and pregnancy of uncertain viability. Statistical analysis involved mixed ANOVAs and the post-hoc Tukey-Kramer test. A total of 160 women were included in the study. Anxiety levels decreased over time for women with a certain diagnosis (n = 128), even when negative (n = 64), and increased over time for women with an uncertain diagnosis (n = 32). Before the ultrasound examination, anxiety levels were high (STAI value, 21.96 ± 1.11) and there was no significant difference between the five groups. Immediately after the ultrasound examination, anxiety levels were lower in the viable IUP group (n = 64; 7.75 ± 1.13) than in any other group. The difference between the five groups was significant (P < 0.005). After 48-72 hours, women with a certain diagnosis had significantly lower anxiety levels than had those with an uncertain diagnosis (10.77 ± 4.30 vs 22.94 ± 1.65; P < 0.005). The experience of abdominal pain and/or vaginal bleeding in early pregnancy is highly anxiogenic. Following an ultrasound examination, the certainty of the diagnosis affects anxiety levels more than does the positive or negative connotations associated with the diagnosis per se. Healthcare providers should be aware of this when communicating uncertain diagnoses. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Multiple point statistical simulation using uncertain (soft) conditional data

NASA Astrophysics Data System (ADS)

Hansen, Thomas Mejer; Vu, Le Thanh; Mosegaard, Klaus; Cordua, Knud Skou

2018-05-01

Geostatistical simulation methods have been used to quantify spatial variability of reservoir models since the 80s. In the last two decades, state of the art simulation methods have changed from being based on covariance-based 2-point statistics to multiple-point statistics (MPS), that allow simulation of more realistic Earth-structures. In addition, increasing amounts of geo-information (geophysical, geological, etc.) from multiple sources are being collected. This pose the problem of integration of these different sources of information, such that decisions related to reservoir models can be taken on an as informed base as possible. In principle, though difficult in practice, this can be achieved using computationally expensive Monte Carlo methods. Here we investigate the use of sequential simulation based MPS simulation methods conditional to uncertain (soft) data, as a computational efficient alternative. First, it is demonstrated that current implementations of sequential simulation based on MPS (e.g. SNESIM, ENESIM and Direct Sampling) do not account properly for uncertain conditional information, due to a combination of using only co-located information, and a random simulation path. Then, we suggest two approaches that better account for the available uncertain information. The first make use of a preferential simulation path, where more informed model parameters are visited preferentially to less informed ones. The second approach involves using non co-located uncertain information. For different types of available data, these approaches are demonstrated to produce simulation results similar to those obtained by the general Monte Carlo based approach. These methods allow MPS simulation to condition properly to uncertain (soft) data, and hence provides a computationally attractive approach for integration of information about a reservoir model.

Evidence-based risk assessment and communication: a new global dengue-risk map for travellers and clinicians#

PubMed Central

Lash, R. Ryan; Johansson, Michael A.; Sharp, Tyler M.; Henry, Ronnie; Brady, Oliver J.; Sotir, Mark J.; Hay, Simon I.; Margolis, Harold S.; Brunette, Gary W.

2016-01-01

Abstract Background: International travel can expose travellers to pathogens not commonly found in their countries of residence, like dengue virus. Travellers and the clinicians who advise and treat them have unique needs for understanding the geographic extent of risk for dengue. Specifically, they should assess the need for prevention measures before travel and ensure appropriate treatment of illness post-travel. Previous dengue-risk maps published in the Centers for Disease Control and Prevention’s Yellow Book lacked specificity, as there was a binary (risk, no risk) classification. We developed a process to compile evidence, evaluate it and apply more informative risk classifications. Methods: We collected more than 839 observations from official reports, ProMED reports and published scientific research for the period 2005–2014. We classified each location as frequent/continuous risk if there was evidence of more than 10 dengue cases in at least three of the previous 10 years. For locations that did not fit this criterion, we classified locations as sporadic/uncertain risk if the location had evidence of at least one locally acquired dengue case during the last 10 years. We used expert opinion in limited instances to augment available data in areas where data were sparse. Results: Initial categorizations classified 134 areas as frequent/continuous and 140 areas as sporadic/uncertain. CDC subject matter experts reviewed all initial frequent/continuous and sporadic/uncertain categorizations and the previously uncategorized areas. From this review, most categorizations stayed the same; however, 11 categorizations changed from the initial determinations. Conclusions: These new risk classifications enable detailed consideration of dengue risk, with clearer meaning and a direct link to the evidence that supports the specific classification. Since many infectious diseases have dynamic risk, strong geographical heterogeneities and varying data quality and availability, using this approach for other diseases can improve the accuracy, clarity and transparency of risk communication. PMID:27625400

Evidence-based risk assessment and communication: a new global dengue-risk map for travellers and clinicians.

PubMed

Jentes, Emily S; Lash, R Ryan; Johansson, Michael A; Sharp, Tyler M; Henry, Ronnie; Brady, Oliver J; Sotir, Mark J; Hay, Simon I; Margolis, Harold S; Brunette, Gary W

2016-06-01

International travel can expose travellers to pathogens not commonly found in their countries of residence, like dengue virus. Travellers and the clinicians who advise and treat them have unique needs for understanding the geographic extent of risk for dengue. Specifically, they should assess the need for prevention measures before travel and ensure appropriate treatment of illness post-travel. Previous dengue-risk maps published in the Centers for Disease Control and Prevention's Yellow Book lacked specificity, as there was a binary (risk, no risk) classification. We developed a process to compile evidence, evaluate it and apply more informative risk classifications. We collected more than 839 observations from official reports, ProMED reports and published scientific research for the period 2005-2014. We classified each location as frequent/continuous risk if there was evidence of more than 10 dengue cases in at least three of the previous 10 years. For locations that did not fit this criterion, we classified locations as sporadic/uncertain risk if the location had evidence of at least one locally acquired dengue case during the last 10 years. We used expert opinion in limited instances to augment available data in areas where data were sparse. Initial categorizations classified 134 areas as frequent/continuous and 140 areas as sporadic/uncertain. CDC subject matter experts reviewed all initial frequent/continuous and sporadic/uncertain categorizations and the previously uncategorized areas. From this review, most categorizations stayed the same; however, 11 categorizations changed from the initial determinations. These new risk classifications enable detailed consideration of dengue risk, with clearer meaning and a direct link to the evidence that supports the specific classification. Since many infectious diseases have dynamic risk, strong geographical heterogeneities and varying data quality and availability, using this approach for other diseases can improve the accuracy, clarity and transparency of risk communication. Published by Oxford University Press 2016. This work is written by US Government employees and is in the public domain in the US.

Resolving structural uncertainty in natural resources management using POMDP approaches

USGS Publications Warehouse

Williams, B.K.

2011-01-01

In recent years there has been a growing focus on the uncertainties of natural resources management, and the importance of accounting for uncertainty in assessing management effectiveness. This paper focuses on uncertainty in resource management in terms of discrete-state Markov decision processes (MDP) under structural uncertainty and partial observability. It describes the treatment of structural uncertainty with approaches developed for partially observable resource systems. In particular, I show how value iteration for partially observable MDPs (POMDP) can be extended to structurally uncertain MDPs. A key difference between these process classes is that structurally uncertain MDPs require the tracking of system state as well as a probability structure for the structure uncertainty, whereas with POMDPs require only a probability structure for the observation uncertainty. The added complexity of the optimization problem under structural uncertainty is compensated by reduced dimensionality in the search for optimal strategy. A solution algorithm for structurally uncertain processes is outlined for a simple example in conservation biology. By building on the conceptual framework developed for POMDPs, natural resource analysts and decision makers who confront structural uncertainties in natural resources can take advantage of the rapid growth in POMDP methods and approaches, and thereby produce better conservation strategies over a larger class of resource problems. ?? 2011.

Impact of soil moisture deficit on ecosystem function across the United States

Treesearch

Susan Moran; Morgan Ross; Mallory Burns

2016-01-01

The cumulative effect of recent prolonged warm drought on regional ecosystem function is still uncertain. Large regions of the United States are experiencing new hydroclimatic conditions with extreme variability in climate drivers such as total precipitation, precipitation patterns (e.g., storm size, intensity and frequency), and seasonal temperatures.

Neural correlates of uncertain decision making: ERP evidence from the Iowa Gambling Task

PubMed Central

Cui, Ji-fang; Chen, Ying-he; Wang, Ya; Shum, David H. K.; Chan, Raymond C. K.

2013-01-01

In our daily life, it is very common to make decisions in uncertain situations. The Iowa Gambling Task (IGT) has been widely used in laboratory studies because of its good simulation of uncertainty in real life activities. The present study aimed to examine the neural correlates of uncertain decision making with the IGT. Twenty-six university students completed this study. An adapted IGT was administered to them, and the EEG data were recorded. The adapted IGT we used allowed us to analyze the choice evaluation, response selection, and feedback evaluation stages of uncertain decision making within the same paradigm. In the choice evaluation stage, the advantageous decks evoked larger P3 amplitude in the left hemisphere, while the disadvantageous decks evoked larger P3 in the right hemisphere. In the response selection stage, the response of “pass” (the card was not turned over; the participants neither won nor lost money) evoked larger negativity preceding the response compared to that of “play” (the card was turned over; the participant either won or lost money). In the feedback evaluation stage, feedback-related negativity (FRN) was only sensitive to the valence (win/loss) but not the magnitude (large/small) of the outcome, and P3 was sensitive to both the valence and the magnitude of the outcome. These results were consistent with the notion that a positive somatic state was represented in the left hemisphere and a negative somatic state was represented in the right hemisphere. There were also anticipatory ERP effects that guided the participants' responses and provided evidence for the somatic marker hypothesis with more precise timing. PMID:24298248

She's My Second Mum: Young People Building Relationships in Uncertain Circumstances

ERIC Educational Resources Information Center

Philip, Kate

2008-01-01

Youth mentoring has become a key element of UK youth policy in recent years and is now integrated into a range of policy initiatives aiming to tackle social exclusion. It is claimed by proponents of planned mentoring that the introduction of a mentor enhances resilience through the provision of a consistent, caring relationship that transcends…

The Influence of Item Response Indecision on the Self-Directed Search

ERIC Educational Resources Information Center

Sampson, James P., Jr.; Shy, Jonathan D.; Hartley, Sarah Lucas; Reardon, Robert C.; Peterson, Gary W.

2009-01-01

Students (N = 247) responded to Self-Directed Search (SDS) per the standard response format and were also instructed to record a question mark (?) for items about which they were uncertain (item response indecision [IRI]). The initial responses of the 114 participants with a (?) were then reversed and a second SDS summary code was obtained and…

Spatial synchrony propagates through a forest food web via consumer-resource interactions

Treesearch

Kyle J. ​Haynes; Andrew M. Liebhold; Todd M. Fearer; Guiming Wang; Gary W. Norman; Derek M. Johnson

2009-01-01

In many study systems, populations fluctuate synchronously across large regions. Several mechanisms have been advanced to explain this, but their importance in nature is often uncertain. Theoretical studies suggest that spatial synchrony initiated in one species through Moran effects may propagate among trophically linked species, but evidence for this in nature is...

Compartmentalization of the yeast meiotic nucleus revealed by analysis of ectopic recombination.

PubMed

Schlecht, Hélène B; Lichten, Michael; Goldman, Alastair S H

2004-11-01

As yeast cells enter meiosis, chromosomes move from a centromere-clustered (Rabl) to a telomere-clustered (bouquet) configuration and then to states of progressive homolog pairing where telomeres are more dispersed. It is uncertain at which stage of this process sequences commit to recombine with each other. Previous analyses using recombination between dispersed homologous sequences (ectopic recombination) support the view that, on average, homologs are aligned end to end by the time of commitment to recombination. We have undertaken further analyses incorporating new inserts, chromosome rearrangements, an alternate mode of recombination initiation, and mutants that disrupt nuclear structure or telomere metabolism. Our findings support previous conclusions and reveal that distance from the nearest telomere is an important parameter influencing recombination between dispersed sequences. In general, the farther dispersed sequences are from their nearest telomere, the less likely they are to engage in ectopic recombination. Neither the mode of initiating recombination nor the formation of the bouquet appears to affect this relationship. We suggest that aspects of telomere localization and behavior influence the organization and mobility of chromosomes along their entire length, during a critical period of meiosis I prophase that encompasses the homology search.

Path planning in uncertain flow fields using ensemble method

NASA Astrophysics Data System (ADS)

Wang, Tong; Le Maître, Olivier P.; Hoteit, Ibrahim; Knio, Omar M.

2016-10-01

An ensemble-based approach is developed to conduct optimal path planning in unsteady ocean currents under uncertainty. We focus our attention on two-dimensional steady and unsteady uncertain flows, and adopt a sampling methodology that is well suited to operational forecasts, where an ensemble of deterministic predictions is used to model and quantify uncertainty. In an operational setting, much about dynamics, topography, and forcing of the ocean environment is uncertain. To address this uncertainty, the flow field is parametrized using a finite number of independent canonical random variables with known densities, and the ensemble is generated by sampling these variables. For each of the resulting realizations of the uncertain current field, we predict the path that minimizes the travel time by solving a boundary value problem (BVP), based on the Pontryagin maximum principle. A family of backward-in-time trajectories starting at the end position is used to generate suitable initial values for the BVP solver. This allows us to examine and analyze the performance of the sampling strategy and to develop insight into extensions dealing with general circulation ocean models. In particular, the ensemble method enables us to perform a statistical analysis of travel times and consequently develop a path planning approach that accounts for these statistics. The proposed methodology is tested for a number of scenarios. We first validate our algorithms by reproducing simple canonical solutions, and then demonstrate our approach in more complex flow fields, including idealized, steady and unsteady double-gyre flows.

Always Gamble on an Empty Stomach: Hunger Is Associated with Advantageous Decision Making

PubMed Central

de Ridder, Denise; Kroese, Floor; Adriaanse, Marieke; Evers, Catharine

2014-01-01

Three experimental studies examined the counterintuitive hypothesis that hunger improves strategic decision making, arguing that people in a hot state are better able to make favorable decisions involving uncertain outcomes. Studies 1 and 2 demonstrated that participants with more hunger or greater appetite made more advantageous choices in the Iowa Gambling Task compared to sated participants or participants with a smaller appetite. Study 3 revealed that hungry participants were better able to appreciate future big rewards in a delay discounting task; and that, in spite of their perception of increased rewarding value of both food and monetary objects, hungry participants were not more inclined to take risks to get the object of their desire. Together, these studies for the first time provide evidence that hot states improve decision making under uncertain conditions, challenging the conventional conception of the detrimental role of impulsivity in decision making. PMID:25340399

Always gamble on an empty stomach: hunger is associated with advantageous decision making.

PubMed

de Ridder, Denise; Kroese, Floor; Adriaanse, Marieke; Evers, Catharine

2014-01-01

Three experimental studies examined the counterintuitive hypothesis that hunger improves strategic decision making, arguing that people in a hot state are better able to make favorable decisions involving uncertain outcomes. Studies 1 and 2 demonstrated that participants with more hunger or greater appetite made more advantageous choices in the Iowa Gambling Task compared to sated participants or participants with a smaller appetite. Study 3 revealed that hungry participants were better able to appreciate future big rewards in a delay discounting task; and that, in spite of their perception of increased rewarding value of both food and monetary objects, hungry participants were not more inclined to take risks to get the object of their desire. Together, these studies for the first time provide evidence that hot states improve decision making under uncertain conditions, challenging the conventional conception of the detrimental role of impulsivity in decision making.

Distributed neural network control for adaptive synchronization of uncertain dynamical multiagent systems.

PubMed

Peng, Zhouhua; Wang, Dan; Zhang, Hongwei; Sun, Gang

2014-08-01

This paper addresses the leader-follower synchronization problem of uncertain dynamical multiagent systems with nonlinear dynamics. Distributed adaptive synchronization controllers are proposed based on the state information of neighboring agents. The control design is developed for both undirected and directed communication topologies without requiring the accurate model of each agent. This result is further extended to the output feedback case where a neighborhood observer is proposed based on relative output information of neighboring agents. Then, distributed observer-based synchronization controllers are derived and a parameter-dependent Riccati inequality is employed to prove the stability. This design has a favorable decouple property between the observer and the controller designs for nonlinear multiagent systems. For both cases, the developed controllers guarantee that the state of each agent synchronizes to that of the leader with bounded residual errors. Two illustrative examples validate the efficacy of the proposed methods.

Observer-based state tracking control of uncertain stochastic systems via repetitive controller

NASA Astrophysics Data System (ADS)

Sakthivel, R.; Susana Ramya, L.; Selvaraj, P.

2017-08-01

This paper develops the repetitive control scheme for state tracking control of uncertain stochastic time-varying delay systems via equivalent-input-disturbance approach. The main purpose of this work is to design a repetitive controller to guarantee the tracking performance under the effects of unknown disturbances with bounded frequency and parameter variations. Specifically, a new set of linear matrix inequality (LMI)-based conditions is derived based on the suitable Lyapunov-Krasovskii functional theory for designing a repetitive controller which guarantees stability and desired tracking performance. More precisely, an equivalent-input-disturbance estimator is incorporated into the control design to reduce the effect of the external disturbances. Simulation results are provided to demonstrate the desired control system stability and their tracking performance. A practical stream water quality preserving system is also provided to show the effectiveness and advantage of the proposed approach.

"The impact of uncertain threat on affective bias: Individual differences in response to ambiguity": Correction.

PubMed

2018-04-01

Reports an error in "The impact of uncertain threat on affective bias: Individual differences in response to ambiguity" by Maital Neta, Julie Cantelon, Zachary Haga, Caroline R. Mahoney, Holly A. Taylor and F. Caroline Davis ( Emotion , 2017[Dec], Vol 17[8], 1137-1143). In this article, the copyright attribution was incorrectly listed under the Creative Commons CC-BY license due to production-related error. The correct copyright should be "In the public domain." The online version of this article has been corrected. (The following abstract of the original article appeared in record 2017-40275-001.) Individuals who operate under highly stressful conditions (e.g., military personnel and first responders) are often faced with the challenge of quickly interpreting ambiguous information in uncertain and threatening environments. When faced with ambiguity, it is likely adaptive to view potentially dangerous stimuli as threatening until contextual information proves otherwise. One laboratory-based paradigm that can be used to simulate uncertain threat is known as threat of shock (TOS), in which participants are told that they might receive mild but unpredictable electric shocks while performing an unrelated task. The uncertainty associated with this potential threat induces a state of emotional arousal that is not overwhelmingly stressful, but has widespread-both adaptive and maladaptive-effects on cognitive and affective function. For example, TOS is thought to enhance aversive processing and abolish positivity bias. Importantly, in certain situations (e.g., when walking home alone at night), this anxiety can promote an adaptive state of heightened vigilance and defense mobilization. In the present study, we used TOS to examine the effects of uncertain threat on valence bias, or the tendency to interpret ambiguous social cues as positive or negative. As predicted, we found that heightened emotional arousal elicited by TOS was associated with an increased tendency to interpret ambiguous cues negatively. Such negative interpretations are likely adaptive in situations in which threat detection is critical for survival and should override an individual's tendency to interpret ambiguity positively in safe contexts. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A Perspective on Multiple Waves of Influenza Pandemics

PubMed Central

Mummert, Anna; Weiss, Howard; Long, Li-Ping; Amigó, José M.; Wan, Xiu-Feng

2013-01-01

Background A striking characteristic of the past four influenza pandemic outbreaks in the United States has been the multiple waves of infections. However, the mechanisms responsible for the multiple waves of influenza or other acute infectious diseases are uncertain. Understanding these mechanisms could provide knowledge for health authorities to develop and implement prevention and control strategies. Materials and Methods We exhibit five distinct mechanisms, each of which can generate two waves of infections for an acute infectious disease. The first two mechanisms capture changes in virus transmissibility and behavioral changes. The third mechanism involves population heterogeneity (e.g., demography, geography), where each wave spreads through one sub-population. The fourth mechanism is virus mutation which causes delayed susceptibility of individuals. The fifth mechanism is waning immunity. Each mechanism is incorporated into separate mathematical models, and outbreaks are then simulated. We use the models to examine the effects of the initial number of infected individuals (e.g., border control at the beginning of the outbreak) and the timing of and amount of available vaccinations. Results Four models, individually or in any combination, reproduce the two waves of the 2009 H1N1 pandemic in the United States, both qualitatively and quantitatively. One model reproduces the two waves only qualitatively. All models indicate that significantly reducing or delaying the initial numbers of infected individuals would have little impact on the attack rate. Instead, this reduction or delay results in a single wave as opposed to two waves. Furthermore, four of these models also indicate that a vaccination program started earlier than October 2009 (when the H1N1 vaccine was initially distributed) could have eliminated the second wave of infection, while more vaccine available starting in October would not have eliminated the second wave. PMID:23637746

A perspective on multiple waves of influenza pandemics.

PubMed

Mummert, Anna; Weiss, Howard; Long, Li-Ping; Amigó, José M; Wan, Xiu-Feng

2013-01-01

A striking characteristic of the past four influenza pandemic outbreaks in the United States has been the multiple waves of infections. However, the mechanisms responsible for the multiple waves of influenza or other acute infectious diseases are uncertain. Understanding these mechanisms could provide knowledge for health authorities to develop and implement prevention and control strategies. We exhibit five distinct mechanisms, each of which can generate two waves of infections for an acute infectious disease. The first two mechanisms capture changes in virus transmissibility and behavioral changes. The third mechanism involves population heterogeneity (e.g., demography, geography), where each wave spreads through one sub-population. The fourth mechanism is virus mutation which causes delayed susceptibility of individuals. The fifth mechanism is waning immunity. Each mechanism is incorporated into separate mathematical models, and outbreaks are then simulated. We use the models to examine the effects of the initial number of infected individuals (e.g., border control at the beginning of the outbreak) and the timing of and amount of available vaccinations. Four models, individually or in any combination, reproduce the two waves of the 2009 H1N1 pandemic in the United States, both qualitatively and quantitatively. One model reproduces the two waves only qualitatively. All models indicate that significantly reducing or delaying the initial numbers of infected individuals would have little impact on the attack rate. Instead, this reduction or delay results in a single wave as opposed to two waves. Furthermore, four of these models also indicate that a vaccination program started earlier than October 2009 (when the H1N1 vaccine was initially distributed) could have eliminated the second wave of infection, while more vaccine available starting in October would not have eliminated the second wave.

Stronger steerability criterion for more uncertain continuous-variable systems

NASA Astrophysics Data System (ADS)

Chowdhury, Priyanka; Pramanik, Tanumoy; Majumdar, A. S.

2015-10-01

We derive a fine-grained uncertainty relation for the measurement of two incompatible observables on a single quantum system of continuous variables, and show that continuous-variable systems are more uncertain than discrete-variable systems. Using the derived fine-grained uncertainty relation, we formulate a stronger steering criterion that is able to reveal the steerability of NOON states that has hitherto not been possible using other criteria. We further obtain a monogamy relation for our steering inequality which leads to an, in principle, improved lower bound on the secret key rate of a one-sided device independent quantum key distribution protocol for continuous variables.

The locus of word frequency effects in skilled spelling-to-dictation.

PubMed

Chua, Shi Min; Liow, Susan J Rickard

2014-01-01

In spelling-to-dictation tasks, skilled spellers consistently initiate spelling of high-frequency words faster than that of low-frequency words. Tainturier and Rapp's model of spelling shows three possible loci for this frequency effect: spoken word recognition, orthographic retrieval, and response execution of the first letter. Thus far, researchers have attributed the effect solely to orthographic retrieval without considering spoken word recognition or response execution. To investigate word frequency effects at each of these three loci, Experiment 1 involved a delayed spelling-to-dictation task and Experiment 2 involved a delayed/uncertain task. In Experiment 1, no frequency effect was found in the 1200-ms delayed condition, suggesting that response execution is not affected by word frequency. In Experiment 2, no frequency effect was found in the delayed/uncertain task that reflects the orthographic retrieval, whereas a frequency effect was found in the comparison immediate/uncertain task that reflects both spoken word recognition and orthographic retrieval. The results of this two-part study suggest that frequency effects in spoken word recognition play a substantial role in skilled spelling-to-dictation. Discrepancies between these findings and previous research, and the limitations of the present study, are discussed.

Modeling Archean Subduction Initiation from Continental Spreading with a Free-Surface

NASA Astrophysics Data System (ADS)

Adams, A.; Thielmann, M.; Golabek, G.

2017-12-01

Earth is the only planet known to have plate tectonics, however the onset of plate tectonics and Earth's early tectonic environment are highly uncertain. Modern plate tectonics are characterized by the sinking of dense lithosphere at subduction zones; however this process may not have been feasible if Earth's interior was hotter in the Archean, resulting in thicker and more buoyant oceanic lithosphere than observed at present [van Hunen and van den Berg, 2008]. Previous studies have proposed gravitational spreading of early continents at passive margins as a mechanism to trigger early episodes of plate subduction using numerical simulations with a free-slip upper boundary condition [Rey et al., 2014]. This study utilizes 2D thermo-mechanical numerical experiments using the finite element code MVEP2 [Kaus, 2010; Thielmann et al., 2014] to investigate the viability of this mechanism for subduction initiation in an Archean mantle for both free-slip and free-surface models. Radiogenic heating, strain weakening, and eclogitization were systematically implemented to determine critical factors for modeling subduction initiation. In free-slip models, results show episodes of continent spreading and subduction initiation of oceanic lithosphere for low limiting yield stresses (100-150 MPa) and increasing continent width with no dependency on radiogenic heating, strain weakening, or eclogitization. For models with a free-surface, subduction initiation was observed at low limiting yield stresses (100-225 MPa) with increasing continent width and only in models with eclogitization. Initial lithospheric stress states were studied as a function of density and viscosity ratios between continent and oceanic lithosphere, and results indicate the magnitude of lithospheric stresses increases with increasing continental buoyancy. This work suggests continent spreading may trigger episodes of subduction in models with a free-surface with critical factors being low limiting yield stresses and eclogitization.

Adaptive Neural Network-Based Event-Triggered Control of Single-Input Single-Output Nonlinear Discrete-Time Systems.

PubMed

Sahoo, Avimanyu; Xu, Hao; Jagannathan, Sarangapani

2016-01-01

This paper presents a novel adaptive neural network (NN) control of single-input and single-output uncertain nonlinear discrete-time systems under event sampled NN inputs. In this control scheme, the feedback signals are transmitted, and the NN weights are tuned in an aperiodic manner at the event sampled instants. After reviewing the NN approximation property with event sampled inputs, an adaptive state estimator (SE), consisting of linearly parameterized NNs, is utilized to approximate the unknown system dynamics in an event sampled context. The SE is viewed as a model and its approximated dynamics and the state vector, during any two events, are utilized for the event-triggered controller design. An adaptive event-trigger condition is derived by using both the estimated NN weights and a dead-zone operator to determine the event sampling instants. This condition both facilitates the NN approximation and reduces the transmission of feedback signals. The ultimate boundedness of both the NN weight estimation error and the system state vector is demonstrated through the Lyapunov approach. As expected, during an initial online learning phase, events are observed more frequently. Over time with the convergence of the NN weights, the inter-event times increase, thereby lowering the number of triggered events. These claims are illustrated through the simulation results.

Using a State Birth Registry as a Quality Improvement Tool.

PubMed

Lannon, Carole; Kaplan, Heather C; Friar, Kelly; Fuller, Sandra; Ford, Susan; White, Beth; Besl, John; Paulson, John; Marcotte, Michael; Krew, Michael; Bailit, Jennifer; Iams, Jay

2017-08-01

Background  Birth registry data are universally collected, generating large administrative datasets. However, these data are typically not used for quality improvement (QI) initiatives in perinatal medicine because the quality and timeliness of the information is uncertain. Objective  We sought to identify and address causes of inaccuracy in recording birth registry information so that birth registry data could support statewide obstetrical quality initiatives in Ohio. Study Design  The Ohio Perinatal Quality Collaborative and the Ohio Department of Health Vital Statistics used QI techniques in 15 medium-sized maternity hospitals to identify and remove systemic sources of inaccuracy in birth registry data. The primary outcome was the rate of scheduled deliveries without medical indication between 37 0/7 and 38 6/7 weeks at participating hospitals from birth registry data. Results  Inaccurate birth registry data most commonly resulted from limited communication between clinical and medical record staff. The rate of scheduled births between 37 0/7 and 38 6/7 weeks' gestation without a documented medical indication as recorded in the birth registry declined by 35%. Conclusion  A QI initiative aimed at increasing the accuracy of birth registry information demonstrated the utility of these data for surveillance of perinatal outcomes and has led to ongoing efforts to support birth registrars in submitting accurate data. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Robust preview control for a class of uncertain discrete-time systems with time-varying delay.

PubMed

Li, Li; Liao, Fucheng

2018-02-01

This paper proposes a concept of robust preview tracking control for uncertain discrete-time systems with time-varying delay. Firstly, a model transformation is employed for an uncertain discrete system with time-varying delay. Then, the auxiliary variables related to the system state and input are introduced to derive an augmented error system that includes future information on the reference signal. This leads to the tracking problem being transformed into a regulator problem. Finally, for the augmented error system, a sufficient condition of asymptotic stability is derived and the preview controller design method is proposed based on the scaled small gain theorem and linear matrix inequality (LMI) technique. The method proposed in this paper not only solves the difficulty problem of applying the difference operator to the time-varying matrices but also simplifies the structure of the augmented error system. The numerical simulation example also illustrates the effectiveness of the results presented in the paper. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Encoding dependence in Bayesian causal networks

USDA-ARS?s Scientific Manuscript database

Bayesian networks (BNs) represent complex, uncertain spatio-temporal dynamics by propagation of conditional probabilities between identifiable states with a testable causal interaction model. Typically, they assume random variables are discrete in time and space with a static network structure that ...

Approximate Reasoning: Past, Present, Future

DTIC Science & Technology

1990-06-27

This note presents a personal view of the state of the art in the representation and manipulation of imprecise and uncertain information by automated ... processing systems. To contrast their objectives and characteristics with the sound deductive procedures of classical logic, methodologies developed

Sampling-based real-time motion planning under state uncertainty for autonomous micro-aerial vehicles in GPS-denied environments.

PubMed

Li, Dachuan; Li, Qing; Cheng, Nong; Song, Jingyan

2014-11-18

This paper presents a real-time motion planning approach for autonomous vehicles with complex dynamics and state uncertainty. The approach is motivated by the motion planning problem for autonomous vehicles navigating in GPS-denied dynamic environments, which involves non-linear and/or non-holonomic vehicle dynamics, incomplete state estimates, and constraints imposed by uncertain and cluttered environments. To address the above motion planning problem, we propose an extension of the closed-loop rapid belief trees, the closed-loop random belief trees (CL-RBT), which incorporates predictions of the position estimation uncertainty, using a factored form of the covariance provided by the Kalman filter-based estimator. The proposed motion planner operates by incrementally constructing a tree of dynamically feasible trajectories using the closed-loop prediction, while selecting candidate paths with low uncertainty using efficient covariance update and propagation. The algorithm can operate in real-time, continuously providing the controller with feasible paths for execution, enabling the vehicle to account for dynamic and uncertain environments. Simulation results demonstrate that the proposed approach can generate feasible trajectories that reduce the state estimation uncertainty, while handling complex vehicle dynamics and environment constraints.

Sampling-Based Real-Time Motion Planning under State Uncertainty for Autonomous Micro-Aerial Vehicles in GPS-Denied Environments

PubMed Central

Li, Dachuan; Li, Qing; Cheng, Nong; Song, Jingyan

2014-01-01

This paper presents a real-time motion planning approach for autonomous vehicles with complex dynamics and state uncertainty. The approach is motivated by the motion planning problem for autonomous vehicles navigating in GPS-denied dynamic environments, which involves non-linear and/or non-holonomic vehicle dynamics, incomplete state estimates, and constraints imposed by uncertain and cluttered environments. To address the above motion planning problem, we propose an extension of the closed-loop rapid belief trees, the closed-loop random belief trees (CL-RBT), which incorporates predictions of the position estimation uncertainty, using a factored form of the covariance provided by the Kalman filter-based estimator. The proposed motion planner operates by incrementally constructing a tree of dynamically feasible trajectories using the closed-loop prediction, while selecting candidate paths with low uncertainty using efficient covariance update and propagation. The algorithm can operate in real-time, continuously providing the controller with feasible paths for execution, enabling the vehicle to account for dynamic and uncertain environments. Simulation results demonstrate that the proposed approach can generate feasible trajectories that reduce the state estimation uncertainty, while handling complex vehicle dynamics and environment constraints. PMID:25412217

A global parallel model based design of experiments method to minimize model output uncertainty.

PubMed

Bazil, Jason N; Buzzard, Gregory T; Rundell, Ann E

2012-03-01

Model-based experiment design specifies the data to be collected that will most effectively characterize the biological system under study. Existing model-based design of experiment algorithms have primarily relied on Fisher Information Matrix-based methods to choose the best experiment in a sequential manner. However, these are largely local methods that require an initial estimate of the parameter values, which are often highly uncertain, particularly when data is limited. In this paper, we provide an approach to specify an informative sequence of multiple design points (parallel design) that will constrain the dynamical uncertainty of the biological system responses to within experimentally detectable limits as specified by the estimated experimental noise. The method is based upon computationally efficient sparse grids and requires only a bounded uncertain parameter space; it does not rely upon initial parameter estimates. The design sequence emerges through the use of scenario trees with experimental design points chosen to minimize the uncertainty in the predicted dynamics of the measurable responses of the system. The algorithm was illustrated herein using a T cell activation model for three problems that ranged in dimension from 2D to 19D. The results demonstrate that it is possible to extract useful information from a mathematical model where traditional model-based design of experiments approaches most certainly fail. The experiments designed via this method fully constrain the model output dynamics to within experimentally resolvable limits. The method is effective for highly uncertain biological systems characterized by deterministic mathematical models with limited data sets. Also, it is highly modular and can be modified to include a variety of methodologies such as input design and model discrimination.

Sensor fault diagnosis of singular delayed LPV systems with inexact parameters: an uncertain system approach

NASA Astrophysics Data System (ADS)

Hassanabadi, Amir Hossein; Shafiee, Masoud; Puig, Vicenc

2018-01-01

In this paper, sensor fault diagnosis of a singular delayed linear parameter varying (LPV) system is considered. In the considered system, the model matrices are dependent on some parameters which are real-time measurable. The case of inexact parameter measurements is considered which is close to real situations. Fault diagnosis in this system is achieved via fault estimation. For this purpose, an augmented system is created by including sensor faults as additional system states. Then, an unknown input observer (UIO) is designed which estimates both the system states and the faults in the presence of measurement noise, disturbances and uncertainty induced by inexact measured parameters. Error dynamics and the original system constitute an uncertain system due to inconsistencies between real and measured values of the parameters. Then, the robust estimation of the system states and the faults are achieved with H∞ performance and formulated with a set of linear matrix inequalities (LMIs). The designed UIO is also applicable for fault diagnosis of singular delayed LPV systems with unmeasurable scheduling variables. The efficiency of the proposed approach is illustrated with an example.

Modeling uncertainty in requirements engineering decision support

NASA Technical Reports Server (NTRS)

Feather, Martin S.; Maynard-Zhang, Pedrito; Kiper, James D.

2005-01-01

One inherent characteristic of requrements engineering is a lack of certainty during this early phase of a project. Nevertheless, decisions about requirements must be made in spite of this uncertainty. Here we describe the context in which we are exploring this, and some initial work to support elicitation of uncertain requirements, and to deal with the combination of such information from multiple stakeholders.

Initial Results of Multigene Panel Testing for Hereditary Breast and Ovarian Cancer and Lynch Syndrome.

PubMed

Howarth, Dt R; Lum, Sharon S; Esquivel, Pamela; Garberoglio, Carlos A; Senthil, Maheswari; Solomon, Naveenraj L

2015-10-01

Multigene panel testing for hereditary cancer risk has recently become commercially available; however, the impact of its use on patient care is undefined. We sought to evaluate results from implementation of panel testing in a multidisciplinary cancer center. We performed a retrospective review of consecutive patients undergoing genetic testing after initiating use of multigene panel testing at Loma Linda University Medical Center. From February 13 to August 25, 2014, 92 patients were referred for genetic testing based on National Comprehensive Cancer Network guidelines. Testing was completed in 90 patients. Overall, nine (10%) pathogenic mutations were identified: five BRCA1/2, and four in non-BRCA loci. Single-site testing identified one BRCA1 and one BRCA2 mutation. The remaining mutations were identified by use of panel testing for hereditary breast and ovarian cancer. There were 40 variants of uncertain significance identified in 34 patients. The use of panel testing more than doubled the identification rate of clinically significant pathogenic mutations that would have been missed with BRCA testing alone. The large number of variants of uncertain significance identified will require long-term follow-up for potential reclassification. Multigene panel testing provides additional information that may improve patient outcomes.

Effects of Heterogeneity and Uncertainties in Sources and Initial and Boundary Conditions on Spatiotemporal Variations of Groundwater Levels

NASA Astrophysics Data System (ADS)

Zhang, Y. K.; Liang, X.

2014-12-01

Effects of aquifer heterogeneity and uncertainties in source/sink, and initial and boundary conditions in a groundwater flow model on the spatiotemporal variations of groundwater level, h(x,t), were investigated. Analytical solutions for the variance and covariance of h(x, t) in an unconfined aquifer described by a linearized Boussinesq equation with a white noise source/sink and a random transmissivity field were derived. It was found that in a typical aquifer the error in h(x,t) in early time is mainly caused by the random initial condition and the error reduces as time goes to reach a constant error in later time. The duration during which the effect of the random initial condition is significant may last a few hundred days in most aquifers. The constant error in groundwater in later time is due to the combined effects of the uncertain source/sink and flux boundary: the closer to the flux boundary, the larger the error. The error caused by the uncertain head boundary is limited in a narrow zone near the boundary but it remains more or less constant over time. The effect of the heterogeneity is to increase the variation of groundwater level and the maximum effect occurs close to the constant head boundary because of the linear mean hydraulic gradient. The correlation of groundwater level decreases with temporal interval and spatial distance. In addition, the heterogeneity enhances the correlation of groundwater level, especially at larger time intervals and small spatial distances.

Connectivity-Preserving Approach for Distributed Adaptive Synchronized Tracking of Networked Uncertain Nonholonomic Mobile Robots.

PubMed

Yoo, Sung Jin; Park, Bong Seok

2017-09-06

This paper addresses a distributed connectivity-preserving synchronized tracking problem of multiple uncertain nonholonomic mobile robots with limited communication ranges. The information of the time-varying leader robot is assumed to be accessible to only a small fraction of follower robots. The main contribution of this paper is to introduce a new distributed nonlinear error surface for dealing with both the synchronized tracking and the preservation of the initial connectivity patterns among nonholonomic robots. Based on this nonlinear error surface, the recursive design methodology is presented to construct the approximation-based local adaptive tracking scheme at the robot dynamic level. Furthermore, a technical lemma is established to analyze the stability and the connectivity preservation of the total closed-loop control system in the Lyapunov sense. An example is provided to illustrate the effectiveness of the proposed methodology.

Robust Economic Control Decision Method of Uncertain System on Urban Domestic Water Supply.

PubMed

Li, Kebai; Ma, Tianyi; Wei, Guo

2018-03-31

As China quickly urbanizes, urban domestic water generally presents the circumstances of both rising tendency and seasonal cycle fluctuation. A robust economic control decision method for dynamic uncertain systems is proposed in this paper. It is developed based on the internal model principle and pole allocation method, and it is applied to an urban domestic water supply system with rising tendency and seasonal cycle fluctuation. To achieve this goal, first a multiplicative model is used to describe the urban domestic water demand. Then, a capital stock and a labor stock are selected as the state vector, and the investment and labor are designed as the control vector. Next, the compensator subsystem is devised in light of the internal model principle. Finally, by using the state feedback control strategy and pole allocation method, the multivariable robust economic control decision method is implemented. The implementation with this model can accomplish the urban domestic water supply control goal, with the robustness for the variation of parameters. The methodology presented in this study may be applied to the water management system in other parts of the world, provided all data used in this study are available. The robust control decision method in this paper is also applicable to deal with tracking control problems as well as stabilization control problems of other general dynamic uncertain systems.

Robust Economic Control Decision Method of Uncertain System on Urban Domestic Water Supply

PubMed Central

Li, Kebai; Ma, Tianyi; Wei, Guo

2018-01-01

As China quickly urbanizes, urban domestic water generally presents the circumstances of both rising tendency and seasonal cycle fluctuation. A robust economic control decision method for dynamic uncertain systems is proposed in this paper. It is developed based on the internal model principle and pole allocation method, and it is applied to an urban domestic water supply system with rising tendency and seasonal cycle fluctuation. To achieve this goal, first a multiplicative model is used to describe the urban domestic water demand. Then, a capital stock and a labor stock are selected as the state vector, and the investment and labor are designed as the control vector. Next, the compensator subsystem is devised in light of the internal model principle. Finally, by using the state feedback control strategy and pole allocation method, the multivariable robust economic control decision method is implemented. The implementation with this model can accomplish the urban domestic water supply control goal, with the robustness for the variation of parameters. The methodology presented in this study may be applied to the water management system in other parts of the world, provided all data used in this study are available. The robust control decision method in this paper is also applicable to deal with tracking control problems as well as stabilization control problems of other general dynamic uncertain systems. PMID:29614749

I saw the sign: the new federal menu-labeling law and lessons from local experience.

PubMed

Banker, Michelle I

2010-01-01

Following the lead of several state and local governments, Congress recently imposed menu-labeling requirements on chain restaurants as part of the federal health care reform bill signed into law in March 2010. Section 4205 of the Patient Protection and Affordable Care Act requires restaurant chains with 20 or more locations nationwide to display calorie information for standard menu items on menus, menu boards, and drive-thru displays. This paper examines the new federal law in light of existing state and local regulations and considers the arguments for and against mandatory calorie labeling at restaurants as a federal tool for preventing obesity. Specifically, this paper examines the provisions of the new federal law, highlights how it differs from the municipal and state menu-labeling laws already in effect, reviews early studies of the effectiveness of these state and local laws, and considers the propriety of requiring restaurants to disclose calorie information on menus by discussing arguments for and against menu labeling generally and calorie labeling in particular. This paper finds that based on initial studies of state and local menu-labeling regulations, the efficacy of compulsory menu labeling as a tool to combat obesity remains uncertain. Finally, this paper raises practical considerations associated with the new federal law, including implementation issues, potential collateral effects of the law, a survey of legal challenges that may arise, and a discussion of the Food and Drug Administration's competence to enforce a menu-labeling requirement against restaurants.

A probabilistic asteroid impact risk model: assessment of sub-300 m impacts

NASA Astrophysics Data System (ADS)

Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

2017-06-01

A comprehensive asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain input parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions for objects up to 300 m in diameter. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data have little effect on the metrics of interest.

Event-Triggered Distributed Control of Nonlinear Interconnected Systems Using Online Reinforcement Learning With Exploration.

PubMed

Narayanan, Vignesh; Jagannathan, Sarangapani

2017-09-07

In this paper, a distributed control scheme for an interconnected system composed of uncertain input affine nonlinear subsystems with event triggered state feedback is presented by using a novel hybrid learning scheme-based approximate dynamic programming with online exploration. First, an approximate solution to the Hamilton-Jacobi-Bellman equation is generated with event sampled neural network (NN) approximation and subsequently, a near optimal control policy for each subsystem is derived. Artificial NNs are utilized as function approximators to develop a suite of identifiers and learn the dynamics of each subsystem. The NN weight tuning rules for the identifier and event-triggering condition are derived using Lyapunov stability theory. Taking into account, the effects of NN approximation of system dynamics and boot-strapping, a novel NN weight update is presented to approximate the optimal value function. Finally, a novel strategy to incorporate exploration in online control framework, using identifiers, is introduced to reduce the overall cost at the expense of additional computations during the initial online learning phase. System states and the NN weight estimation errors are regulated and local uniformly ultimately bounded results are achieved. The analytical results are substantiated using simulation studies.

Forecasting seasonal influenza with a state-space SIR model.

PubMed

Osthus, Dave; Hickmann, Kyle S; Caragea, Petruţa C; Higdon, Dave; Del Valle, Sara Y

2017-03-01

Seasonal influenza is a serious public health and societal problem due to its consequences resulting from absenteeism, hospitalizations, and deaths. The overall burden of influenza is captured by the Centers for Disease Control and Prevention's influenza-like illness network, which provides invaluable information about the current incidence. This information is used to provide decision support regarding prevention and response efforts. Despite the relatively rich surveillance data and the recurrent nature of seasonal influenza, forecasting the timing and intensity of seasonal influenza in the U.S. remains challenging because the form of the disease transmission process is uncertain, the disease dynamics are only partially observed, and the public health observations are noisy. Fitting a probabilistic state-space model motivated by a deterministic mathematical model [a susceptible-infectious-recovered (SIR) model] is a promising approach for forecasting seasonal influenza while simultaneously accounting for multiple sources of uncertainty. A significant finding of this work is the importance of thoughtfully specifying the prior, as results critically depend on its specification. Our conditionally specified prior allows us to exploit known relationships between latent SIR initial conditions and parameters and functions of surveillance data. We demonstrate advantages of our approach relative to alternatives via a forecasting comparison using several forecast accuracy metrics.

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

Deshmukh, Ranjit; Bharvirkar, Ranjit; Gambhir, Ashwin

Although solar costs are dropping rapidly, solar power is still more expensive than conventional and other renewable energy options. The solar sector still needs continuing government policy support. These policies are driven by objectives that go beyond the goal of achieving grid parity. The need to achieve multiple objectives and ensure sufficient political support for solar power makes it diffi cult for policy makers to design the optimal solar power policy. The dynamic and uncertain nature of the solar industry, combined with the constraints offered by broader economic, political and social conditions further complicates the task of policy making. Thismore » report presents an analysis of solar promotion policies in seven countries - Germany, Spain, the United States, Japan, China, Taiwan, and India - in terms of their outlook, objectives, policy mechanisms and outcomes. The report presents key insights, primarily in qualitative terms, and recommendations for two distinct audiences. The first audience consists of global policy makers who are exploring various mechanisms to increase the penetration of solar power in markets to mitigate climate change. The second audience consists of key Indian policy makers who are developing a long-term implementation plan under the Jawaharlal Nehru National Solar Mission and various state initiatives.« less

Guided by Principles. Shaping the State of California's Role in K-12 Public School Facility Funding. Full Policy Research Working Paper

ERIC Educational Resources Information Center

Vincent, Jeffrey M.; Gross, Liz S.

2015-01-01

K-12 public school facilities need regular investment to ensure student health and safety and support educational programming. Yet, the future of K-12 school facility funding in California is uncertain. A strong state-local partnership has existed that funded new construction, modernization, and other investments in public school facilities across…

Projected tree species redistribution under climate change: Implications for ecosystem vulnerability across protected areas in the eastern United States

Treesearch

Scott G. Zolkos; Patrick Jantz; Tina Cormier; Louis R. Iverson; Daniel W. McKenney; Scott J. Goetz

2015-01-01

The degree to which tree species will shift in response to climate change is uncertain yet critical to understand for assessing ecosystem vulnerability. We analyze results from recent studies that model potential tree species habitat across the eastern United States during the coming century. Our goals were to quantify and spatially analyze habitat projections and...

Streamflow forecasting and data assimilation: bias in precipitation, soil moisture states, and groundwater fluxes.

NASA Astrophysics Data System (ADS)

McCreight, J. L.; Gochis, D. J.; Hoar, T.; Dugger, A. L.; Yu, W.

2014-12-01

Uncertainty in precipitation forcing, soil moisture states, and model groundwater fluxes are first-order sources of error in streamflow forecasting. While near-surface estimates of soil moisture are now available from satellite, very few soil moisture observations below 5 cm depth or groundwater discharge estimates are available for operational forecasting. Radar precipitation estimates are subject to large biases, particularly during extreme events (e.g. Steiner et al., 2010) and their correction is not typically available in real-time. Streamflow data, however, are readily available in near-real-time and can be assimilated operationally to help constrain uncertainty in these uncertain states and improve streamflow forecasts. We examine the ability of streamflow observations to diagnose bias in the three most uncertain variables: precipitation forcing, soil moisture states, and groundwater fluxes. We investigate strategies for their subsequent bias correction. These include spinup and calibration strategies with and without the use of data assimilation and the determination of the proper spinup timescales. Global and spatially distributed multipliers on the uncertain states included in the assimilation state vector (e.g. Seo et al., 2003) will also be evaluated. We examine real cases and observing system simulation experiments for both normal and extreme rainfall events. One of our test cases considers the Colorado Front Range flood of September 2013 where the range of disagreement amongst five precipitation estimates spanned a factor of five with only one exhibiting appreciable positive bias (Gochis et al, submitted). Our experiments are conducted using the WRF-Hydro model with the NoahMP land surface component and the data assimilation research testbed (DART). A variety of ensemble data assimilation approaches (filters) are considered. ReferencesGochis, DJ, et al. "The Great Colorado Flood of September 2013" BAMS (Submitted 4-7-14). Seo, DJ, V Koren, and N Cajina. "Real-time variational assimilation of hydrologic and hydrometeorological data into operational hydrologic forecasting." J Hydromet (2003). Steiner, Matthias, JA Smith, SJ Burges, CV Alonso, and RW Darden. "Effect of bias adjustment and rain gauge data quality control on radar rainfall estimation." WRR (1999).

Identifying Model-Based Reconfiguration Goals through Functional Deficiencies

NASA Technical Reports Server (NTRS)

Benazera, Emmanuel; Trave-Massuyes, Louise

2004-01-01

Model-based diagnosis is now advanced to the point autonomous systems face some uncertain and faulty situations with success. The next step toward more autonomy is to have the system recovering itself after faults occur, a process known as model-based reconfiguration. After faults occur, given a prediction of the nominal behavior of the system and the result of the diagnosis operation, this paper details how to automatically determine the functional deficiencies of the system. These deficiencies are characterized in the case of uncertain state estimates. A methodology is then presented to determine the reconfiguration goals based on the deficiencies. Finally, a recovery process interleaves planning and model predictive control to restore the functionalities in prioritized order.

Making certain progress in uncertain times : the Transportation Research Board's 2008 Field Visit Program

DOT National Transportation Integrated Search

2009-01-01

Each year, TRBs Technical Activities Division staff visit state departments of transportation, as well as selected universities, transit and other modal agencies, and industry organizations, to determine the issues they are facing and how TRB can ...

A critical needs assessment for collaborative ecotourism development linked to protected areas in Cross River State, Nigeria

Treesearch

Jeffrey J. Brooks; John Neary; Blessing E. Asuquo

2007-01-01

Nigeria has abundant natural resources, and the nation, working with its partners over the years, has made large strides toward conservation of this natural wealth, but the future of Nigeria's natural resources remains uncertain.

Immune thrombocytopenia: No longer ‘idiopathic’

PubMed Central

McCRAE, KEITH

2012-01-01

Immune thrombocytopenia (ITP) is a common hematologic disorder. Its pathogenesis involves both accelerated platelet destruction and impaired platelet production. First-line agents are usually effective initially but do not provide long-term responses. Splenectomy remains an effective long-term therapy, as does rituximab (Rituxan) in a subset of patients. Thrombopoietic agents offer a new alternative, although their place in the overall management of ITP remains uncertain. PMID:21632906

Autonomous Vehicle Systems Laboratory Research Capability Expansion Program

DTIC Science & Technology

2017-12-03

currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. University of the Incarnate Word 4301 Broadway, Box #T-2 San Antonio...autonomous control , collaboration, and decision-making in unstructured, dynamic, and uncertain nonlinear environments for autonomous ground and air...vehicle systems. To fulfill the research goal, the PI has initiated fundamental research in the areas of autonomous rotorcraft control and

Uranium/Thorium Dating and Growth Laminae Counting of Stalagmites Reveal a Record of Major Earthquakes in the Midwestern US

NASA Astrophysics Data System (ADS)

Zhang, Z.; Lundstrom, C.; Panno, S.; Hackley, K. C.; Fouke, B. W.; Curry, B.

2009-12-01

The recurrence interval of large New Madrid Seismic Zone (NMSZ) earthquakes is uncertain because of the limited number and likely incomplete nature of the record of dated seismic events. Data on paleoseismicity in this area is necessary for refining estimates of a recurrence interval for these earthquakes and for characterizing the geophysical nature of the NMSZ. Studies of the paleoseismic history of the NMSZ have previously used liquefaction features and flood plain deposits along the Mississippi River to estimate recurrence interval with considerable uncertainties. More precise estimates of the number and ages of paleoseismic events would enhance the ability of federal, state, and local agencies to make critical preparedness decisions. Initiation of new speleothems (cave deposits) has been shown in several localities to record large earthquake events. Our ongoing work in caves of southwestern Illinois, Missouri, Indiana and Arkansas has used both U/Th age dating techniques and growth laminae counting of actively growing stalagmites to determine the age of initiation of stalagmites in caves across the Midwestern U.S. These age initiations cluster around two known events, the great NMSZ earthquakes of 1811-1812 and the Missouri earthquake of 1917, suggesting that cave deposits in this region constitute a unique record of paleo-seismic history of the NMSZ. Furthermore, the U-Th disequilibria growth laminae ages of young, white stalagmites and of older stalagmites on which they grew, plus published Holocene stalagmite ages of initiation and regrowth from Missouri caves, are all coincident with suspected NMSZ earthquakes based on liquefaction and other paleoseimic techniques. We hypothesize that these speleothems were initiated by earthquake-induced opening/closing of fracture-controlled flowpaths in the ceilings of cave passages.

State-space self-tuner for on-line adaptive control

NASA Technical Reports Server (NTRS)

Shieh, L. S.

1994-01-01

Dynamic systems, such as flight vehicles, satellites and space stations, operating in real environments, constantly face parameter and/or structural variations owing to nonlinear behavior of actuators, failure of sensors, changes in operating conditions, disturbances acting on the system, etc. In the past three decades, adaptive control has been shown to be effective in dealing with dynamic systems in the presence of parameter uncertainties, structural perturbations, random disturbances and environmental variations. Among the existing adaptive control methodologies, the state-space self-tuning control methods, initially proposed by us, are shown to be effective in designing advanced adaptive controllers for multivariable systems. In our approaches, we have embedded the standard Kalman state-estimation algorithm into an online parameter estimation algorithm. Thus, the advanced state-feedback controllers can be easily established for digital adaptive control of continuous-time stochastic multivariable systems. A state-space self-tuner for a general multivariable stochastic system has been developed and successfully applied to the space station for on-line adaptive control. Also, a technique for multistage design of an optimal momentum management controller for the space station has been developed and reported in. Moreover, we have successfully developed various digital redesign techniques which can convert a continuous-time controller to an equivalent digital controller. As a result, the expensive and unreliable continuous-time controller can be implemented using low-cost and high performance microprocessors. Recently, we have developed a new hybrid state-space self tuner using a new dual-rate sampling scheme for on-line adaptive control of continuous-time uncertain systems.

Developing the Safety of Atrial Fibrillation Ablation Registry Initiative (SAFARI) as a collaborative pan-stakeholder critical path registry model: a Cardiac Safety Research Consortium "Incubator" Think Tank.

PubMed

Al-Khatib, Sana M; Calkins, Hugh; Eloff, Benjamin C; Kowey, Peter; Hammill, Stephen C; Ellenbogen, Kenneth A; Marinac-Dabic, Danica; Waldo, Albert L; Brindis, Ralph G; Wilbur, David J; Jackman, Warren M; Yaross, Marcia S; Russo, Andrea M; Prystowsky, Eric; Varosy, Paul D; Gross, Thomas; Pinnow, Ellen; Turakhia, Mintu P; Krucoff, Mitchell W

2010-10-01

Although several randomized clinical trials have demonstrated the safety and efficacy of catheter ablation of atrial fibrillation (AF) in experienced centers, the outcomes of this procedure in routine clinical practice and in patients with persistent and long-standing persistent AF remain uncertain. Brisk adoption of this therapy by physicians with diverse training and experience highlights potential concerns regarding the safety and effectiveness of this procedure. Some of these concerns could be addressed by a national registry of AF ablation procedures such as the Safety of Atrial Fibrillation Ablation Registry Initiative that was initially proposed at a Cardiac Safety Research Consortium Think Tank meeting in April 2009. In January 2010, the Cardiac Safety Research Consortium, in collaboration with the Duke Clinical Research Institute, the US Food and Drug Administration, the American College of Cardiology, and the Heart Rhythm Society, held a follow-up meeting of experts in the field to review the construct and progress to date. Other participants included the National Heart, Lung, and Blood Institute; the Centers for Medicare and Medicaid Services; the Agency for Healthcare Research and Quality; the AdvaMed AF working group; and additional industry representatives. This article summarizes the discussions that occurred at the meeting of the state of the Safety of Atrial Fibrillation Ablation Registry Initiative, the identification of a clear pathway for its implementation, and the exploration of solutions to potential issues in the execution of this registry. Copyright © 2010 Mosby, Inc. All rights reserved.

Price, carbon and generation profiles: how partisan differences make the future of climate change uncertain

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

Sautter, John A.; Sautter, Christopher A.

America is very much a divided nation when it comes to politics. That polarization is reflected in the environmental and energy realities currently at play in many states, creating a remarkable divide between more conservative Red States and more liberal Blue States when it comes to the amount of CO{sub 2} emitted into the atmosphere and the price of electricity. These differences pose an enormous obstacle in passing climate change legislation. (author)

Summary of Research Report

NASA Technical Reports Server (NTRS)

Elishakoff, Isaac

1998-01-01

Ten papers, published in various publications, on buckling, and the effects of imperfections on various structures are presented. These papers are: (1) Buckling mode localization in elastic plates due to misplacement in the stiffner location; (2) On vibrational imperfection sensitivity on Augusti's model structure in the vicinity of a non-linear static state; (3) Imperfection sensitivity due to elastic moduli in the Roorda Koiter frame; (4) Buckling mode localization in a multi-span periodic structure with a disorder in a single span; (5) Prediction of natural frequency and buckling load variability due to uncertainty in material properties by convex modeling; (6) Derivation of multi-dimensional ellipsoidal convex model for experimental data; (7) Passive control of buckling deformation via Anderson localization phenomenon; (8)Effect of the thickness and initial im perfection on buckling on composite cylindrical shells: asymptotic analysis and numerical results by BOSOR4 and PANDA2; (9) Worst case estimation of homology design by convex analysis; (10) Buckling of structures with uncertain imperfections - Personal perspective.

Don't "Short Circuit" STEM Instruction

ERIC Educational Resources Information Center

Bruxvoort, Crystal; Jadrich, James

2016-01-01

Science students should undertake engineering design projects and carry out scientific investigations, as recommended by the "Next Generation Science Standards" (NGSS Lead States 2013). However, studies show that students misconstrue the goals of science and engineering and are uncertain about their respective practices (Gilbert and Wade…

Toward Sustainable Water Resource Management: Challenges and Opportunities

EPA Science Inventory

The United States has derived significant economic benefit from an abundant and high-quality water supply. The ability of the nation to continue this pace into the future is uncertain because of a number of significant challenges. These include increasing water demand because of ...

Finite-time adaptive sliding mode force control for electro-hydraulic load simulator based on improved GMS friction model

NASA Astrophysics Data System (ADS)

Kang, Shuo; Yan, Hao; Dong, Lijing; Li, Changchun

2018-03-01

This paper addresses the force tracking problem of electro-hydraulic load simulator under the influence of nonlinear friction and uncertain disturbance. A nonlinear system model combined with the improved generalized Maxwell-slip (GMS) friction model is firstly derived to describe the characteristics of load simulator system more accurately. Then, by using particle swarm optimization (PSO) algorithm ​combined with the system hysteresis characteristic analysis, the GMS friction parameters are identified. To compensate for nonlinear friction and uncertain disturbance, a finite-time adaptive sliding mode control method is proposed based on the accurate system model. This controller has the ability to ensure that the system state moves along the nonlinear sliding surface to steady state in a short time as well as good dynamic properties under the influence of parametric uncertainties and disturbance, which further improves the force loading accuracy and rapidity. At the end of this work, simulation and experimental results are employed to demonstrate the effectiveness of the proposed sliding mode control strategy.

Adaptive Neural Networks Prescribed Performance Control Design for Switched Interconnected Uncertain Nonlinear Systems.

PubMed

Li, Yongming; Tong, Shaocheng

2017-06-28

In this paper, an adaptive neural networks (NNs)-based decentralized control scheme with the prescribed performance is proposed for uncertain switched nonstrict-feedback interconnected nonlinear systems. It is assumed that nonlinear interconnected terms and nonlinear functions of the concerned systems are unknown, and also the switching signals are unknown and arbitrary. A linear state estimator is constructed to solve the problem of unmeasured states. The NNs are employed to approximate unknown interconnected terms and nonlinear functions. A new output feedback decentralized control scheme is developed by using the adaptive backstepping design technique. The control design problem of nonlinear interconnected switched systems with unknown switching signals can be solved by the proposed scheme, and only a tuning parameter is needed for each subsystem. The proposed scheme can ensure that all variables of the control systems are semi-globally uniformly ultimately bounded and the tracking errors converge to a small residual set with the prescribed performance bound. The effectiveness of the proposed control approach is verified by some simulation results.

Rescattering effects on intensity interferometry and initial conditions in relativistic heavy ion collisions

NASA Astrophysics Data System (ADS)

Li, Yang

The properties of the quark-gluon plasma are being thoroughly studied by utilizing relativistic heavy ion collisions. After its invention in astronomy in the 1950s, intensity interferometry was found to be a robust method to probe the spatial and temporal information of the nuclear collisions also. Although rescattering effects are negligible in elementary particle collisions, it may be very important for heavy ion collisions at RHIC and in the future LHC. Rescattering after production will modify the measured correlation function and make it harder to extract the dynamical information from data. To better understand the data which are dimmed by this final state process, we derive a general formula for intensity interferometry which can calculate rescattering effects easily. The formula can be used both non-relativistically and relativistically. Numerically, we found that rescattering effects on kaon interferometry for RHIC experiments can modify the measured ratio of the outward radius to the sideward radius, which is a sensitive probe to the equation of state, by as large as 15%. It is a nontrivial contribution which should be included to understand the data more accurately. The second part of this thesis is on the initial conditions in relativistic heavy ion collisions. Although relativistic hydrodynamics is successful in explaining many aspects of the data, it is only valid after some finite time after nuclear contact. The results depend on the choice of initial conditions which, so far, have been very uncertain. I describe a formula based on the McLerran-Venugopalan model to compute the initial energy density. The soft gluon fields produced immediately after the overlap of the nuclei can be expanded as a power series of the proper time t. Solving Yang-Mills equations with color current conservation can give us the analytical formulas for the fields. The local color charges on the transverse plane are stochastic variables and have to be taken care of by random walks. It is found that the fields are mainly longitudinal at early time. The initial energy densities are computed both for RHIC and LHC.

Uncertain Recovery: Access and Funding Issues in Public Higher Education. Findings from the 2010 Survey of the National Council of State Directors of Community Colleges

ERIC Educational Resources Information Center

Katsinas, Stephen G.; Friedel, Janice N.

2010-01-01

There are growing pressures for community colleges and regional universities to accommodate the rise in student enrollment. The purpose of this study was to evaluate access and funding issues across public higher education institutions in the United States. Responses to a survey, conducted by the Education Policy Center at the University of…

Online K-12 Schooling in the U.S.: Uncertain Private Ventures in Need of Public Regulation

ERIC Educational Resources Information Center

Glass, Gene V.; Welner, Kevin G.

2011-01-01

Over just the past decade, online learning at the K-12 level has grown from a novelty to a movement. Often using the authority and mechanism of state charters, and in league with home schoolers and other allies, private companies and some state entities are now providing full-time online schooling to a rapidly increasing number of students in the…

The Effect of Mandatory Furloughs on Self-Determination, Financial Strain, and Decision to Leave the California State University System in Social Work Faculty

ERIC Educational Resources Information Center

Hohman, Melinda; Packard, Thomas; Finnegan, Daniel; Jones, Loring

2013-01-01

In uncertain economic times, universities have taken steps to address financial problems by including the use of business models. In 2009, the California State University (CSU) system implemented furloughs of a 10% pay reduction and 18 days removed from the academic calendar. Faculty in 16 CSU schools of social work participated in a Web-based…

Interstitial cystitis intravesical therapy

PubMed Central

2017-01-01

Interstitial cystitis (IC) is a progressive bladder disorder that presents with symptoms of bladder urgency, frequency and pain. The aetiology of the disease remains uncertain, but it is postulated that there is an initial infective insult which damages the glycosaminoglycan (GAG) layer of the bladder urothelium. This defect allows an influx of ions, particularly potassium, which initiates an inflammatory reaction in the bladder wall, which incites the symptoms described above. Treatment initially involves behavioural and oral medication, with second line being intravesical instillation therapy. Treatment strategies focus on restoring lower urinary tract epithelial function, inhibiting neural activation, controlling allergies and relieving symptoms. In this review, current intravesical therapy will be discussed, as well as what lies on the horizon for intravesical therapy in IC. PMID:28791236

Adaptive NN Control Using Integral Barrier Lyapunov Functionals for Uncertain Nonlinear Block-Triangular Constraint Systems.

PubMed

Liu, Yan-Jun; Tong, Shaocheng; Chen, C L Philip; Li, Dong-Juan

2017-11-01

A neural network (NN) adaptive control design problem is addressed for a class of uncertain multi-input-multi-output (MIMO) nonlinear systems in block-triangular form. The considered systems contain uncertainty dynamics and their states are enforced to subject to bounded constraints as well as the couplings among various inputs and outputs are inserted in each subsystem. To stabilize this class of systems, a novel adaptive control strategy is constructively framed by using the backstepping design technique and NNs. The novel integral barrier Lyapunov functionals (BLFs) are employed to overcome the violation of the full state constraints. The proposed strategy can not only guarantee the boundedness of the closed-loop system and the outputs are driven to follow the reference signals, but also can ensure all the states to remain in the predefined compact sets. Moreover, the transformed constraints on the errors are used in the previous BLF, and accordingly it is required to determine clearly the bounds of the virtual controllers. Thus, it can relax the conservative limitations in the traditional BLF-based controls for the full state constraints. This conservatism can be solved in this paper and it is for the first time to control this class of MIMO systems with the full state constraints. The performance of the proposed control strategy can be verified through a simulation example.

Teacher Education in the United States of America, 2011

ERIC Educational Resources Information Center

Imig, David; Wiseman, Donna; Imig, Scott

2011-01-01

Teacher education in the USA is faced with an uncertain future. Unprecedented efforts on the part of government, philanthropic foundations, social entrepreneurs, professional societies and others are reshaping the enterprise. Warring camps have emerged to promote decidedly different visions for teacher education, with university-based teacher…

Growing and Funding Experiential Learning Programs: A Recipe for Success

ERIC Educational Resources Information Center

Cowart, Monica R.

2010-01-01

While numerous professors and administrators can agree upon the benefits of infusing the curriculum with experiential learning, a commonly stated obstacle to widespread curricular reform is funding. Specifically, given that external institutional support can be difficult to procure, especially in uncertain economic times, institutions might…

U.S. Fruit and Vegetable Processing Industries.

ERIC Educational Resources Information Center

Buckley, Katharine C.; And Others

Because of shifts in consumer tastes and preferences, demographics, technology, government regulation, and the expanding interdependence of world markets, the United States fruit and vegetable processing industries must operate in a constantly changing and uncertain economic environment. U.S. per capita use of processed fruits and vegetables is…

Decision Topology Assessment in Engineering Design Under Uncertainity

DTIC Science & Technology

2014-01-01

those of the United States Government or the DoA, and shall not be used for advertising or product endorsement purposes. REFERENCES 1. Clemen ...Raiffa, H., 1994, Decisions with Multiple Objectives, Cambridge University Press, Cambridge, United Kingdom. 6. Lewis, K., W. Chen, and L.C. Schmidt

Quantitative local analysis of nonlinear systems

NASA Astrophysics Data System (ADS)

Topcu, Ufuk

This thesis investigates quantitative methods for local robustness and performance analysis of nonlinear dynamical systems with polynomial vector fields. We propose measures to quantify systems' robustness against uncertainties in initial conditions (regions-of-attraction) and external disturbances (local reachability/gain analysis). S-procedure and sum-of-squares relaxations are used to translate Lyapunov-type characterizations to sum-of-squares optimization problems. These problems are typically bilinear/nonconvex (due to local analysis rather than global) and their size grows rapidly with state/uncertainty space dimension. Our approach is based on exploiting system theoretic interpretations of these optimization problems to reduce their complexity. We propose a methodology incorporating simulation data in formal proof construction enabling more reliable and efficient search for robustness and performance certificates compared to the direct use of general purpose solvers. This technique is adapted both to region-of-attraction and reachability analysis. We extend the analysis to uncertain systems by taking an intentionally simplistic and potentially conservative route, namely employing parameter-independent rather than parameter-dependent certificates. The conservatism is simply reduced by a branch-and-hound type refinement procedure. The main thrust of these methods is their suitability for parallel computing achieved by decomposing otherwise challenging problems into relatively tractable smaller ones. We demonstrate proposed methods on several small/medium size examples in each chapter and apply each method to a benchmark example with an uncertain short period pitch axis model of an aircraft. Additional practical issues leading to a more rigorous basis for the proposed methodology as well as promising further research topics are also addressed. We show that stability of linearized dynamics is not only necessary but also sufficient for the feasibility of the formulations in region-of-attraction analysis. Furthermore, we generalize an upper bound refinement procedure in local reachability/gain analysis which effectively generates non-polynomial certificates from polynomial ones. Finally, broader applicability of optimization-based tools stringently depends on the availability of scalable/hierarchial algorithms. As an initial step toward this direction, we propose a local small-gain theorem and apply to stability region analysis in the presence of unmodeled dynamics.

Earthquakes, Cancer and Cultures of Fear: Qualifying as a Skills for Life Teacher in an Uncertain Economic Climate

ERIC Educational Resources Information Center

O'Leary, Matt; Smith, Rob

2012-01-01

The Skills for Life (SfL) initiative followed the Moser Report (1999) and incarnated a Third Way agenda that sought to address England's perceived adult skills deficit. SfL marked a large investment in adult education but also a distinct shift to a more focused, instrumentalist role for Further Education (FE) in England. A new structure of teacher…

Back from the Future: The Impact of Change on Airpower in the Decades Ahead

DTIC Science & Technology

2009-01-01

generic/story_generic.jsp?channel= awst &id=news/aw021108p2.xml&headline=Fate%20of%20F -22,%20C-17%20Lines%20Uncertain%20in%20Fiscal%202009; Pierre Sprey...second lot of low-rate initial production aircraft was announced on 22 May 2008 as $2.2 billion for 12 aircraft, and Maj Gen Charles R . Davis, USAF, the

Uncertainty-Sensitive Heterogeneous Information Fusion: Assessing Threat with Soft, Uncertain, and Conflicting Evidence

DTIC Science & Technology

2016-01-01

planning exercises and wargaming. Initial Experimentation Late in the research , the prototype platform and the various fusion methods came together. This...Chapter Four points to prior research 2 Uncertainty-Sensitive Heterogeneous Information Fusion in mind multimethod fusing of complex information...our research is assessing the threat of terrorism posed by individuals or groups under scrutiny. Broadly, the ultimate objec- tives, which go well

The Framework for Life Cycle Cost Management,

DTIC Science & Technology

1982-01-01

in the early phases of system development before full- scale development and initial production, O&S cost projections are too un- certain to...Ensure that each increment of cost and schedule investment in R&M contributes significantly to the above objectives. DoDD 5000.40, Reliability and...Major systems are characterized by large investments of time and resources in the uncertain periods of development, production, and deployment and in

Portfolio theory and cost-effectiveness analysis: a further discussion.

PubMed

Sendi, Pedram; Al, Maiwenn J; Rutten, Frans F H

2004-01-01

Portfolio theory has been suggested as a means to improve the risk-return characteristics of investments in health-care programs through diversification when costs and effects are uncertain. This approach is based on the assumption that the investment proportions are not subject to uncertainty and that the budget can be invested in toto in health-care programs. In the present paper we develop an algorithm that accounts for the fact that investment proportions in health-care programs may be uncertain (due to the uncertainty associated with costs) and limited (due to the size of the programs). The initial budget allocation across programs may therefore be revised at the end of the investment period to cover the extra costs of some programs with the leftover budget of other programs in the portfolio. Once the total budget is equivalent to or exceeds the expected costs of the programs in the portfolio, the initial budget allocation policy does not impact the risk-return characteristics of the combined portfolio, i.e., there is no benefit from diversification anymore. The applicability of portfolio methods to improve the risk-return characteristics of investments in health care is limited to situations where the available budget is much smaller than the expected costs of the programs to be funded.

Finite-time master-slave synchronization and parameter identification for uncertain Lurie systems.

PubMed

Wang, Tianbo; Zhao, Shouwei; Zhou, Wuneng; Yu, Weiqin

2014-07-01

This paper investigates the finite-time master-slave synchronization and parameter identification problem for uncertain Lurie systems based on the finite-time stability theory and the adaptive control method. The finite-time master-slave synchronization means that the state of a slave system follows with that of a master system in finite time, which is more reasonable than the asymptotical synchronization in applications. The uncertainties include the unknown parameters and noise disturbances. An adaptive controller and update laws which ensures the synchronization and parameter identification to be realized in finite time are constructed. Finally, two numerical examples are given to show the effectiveness of the proposed method. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive output-feedback control for switched stochastic uncertain nonlinear systems with time-varying delay.

PubMed

Song, Zhibao; Zhai, Junyong

2018-04-01

This paper addresses the problem of adaptive output-feedback control for a class of switched stochastic time-delay nonlinear systems with uncertain output function, where both the control coefficients and time-varying delay are unknown. The drift and diffusion terms are subject to unknown homogeneous growth condition. By virtue of adding a power integrator technique, an adaptive output-feedback controller is designed to render that the closed-loop system is bounded in probability, and the state of switched stochastic nonlinear system can be globally regulated to the origin almost surely. A numerical example is provided to demonstrate the validity of the proposed control method. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Anti-windup adaptive PID control design for a class of uncertain chaotic systems with input saturation.

PubMed

Tahoun, A H

2017-01-01

In this paper, the stabilization problem of actuators saturation in uncertain chaotic systems is investigated via an adaptive PID control method. The PID control parameters are auto-tuned adaptively via adaptive control laws. A multi-level augmented error is designed to account for the extra terms appearing due to the use of PID and saturation. The proposed control technique uses both the state-feedback and the output-feedback methodologies. Based on Lyapunov׳s stability theory, new anti-windup adaptive controllers are proposed. Demonstrative examples with MATLAB simulations are studied. The simulation results show the efficiency of the proposed adaptive PID controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

The Effects of the Previous Outcome on Probabilistic Choice in Rats

PubMed Central

Marshall, Andrew T.; Kirkpatrick, Kimberly

2014-01-01

This study examined the effects of previous outcomes on subsequent choices in a probabilistic-choice task. Twenty-four rats were trained to choose between a certain outcome (1 or 3 pellets) versus an uncertain outcome (3 or 9 pellets), delivered with a probability of .1, .33, .67, and .9 in different phases. Uncertain outcome choices increased with the probability of uncertain food. Additionally, uncertain choices increased with the probability of uncertain food following both certain-choice outcomes and unrewarded uncertain choices. However, following uncertain-choice food outcomes, there was a tendency to choose the uncertain outcome in all cases, indicating that the rats continued to “gamble” after successful uncertain choices, regardless of the overall probability or magnitude of food. A subsequent manipulation, in which the probability of uncertain food varied within each session as a function of the previous uncertain outcome, examined how the previous outcome and probability of uncertain food affected choice in a dynamic environment. Uncertain-choice behavior increased with the probability of uncertain food. The rats exhibited increased sensitivity to probability changes and a greater degree of win–stay/lose–shift behavior than in the static phase. Simulations of two sequential choice models were performed to explore the possible mechanisms of reward value computations. The simulation results supported an exponentially decaying value function that updated as a function of trial (rather than time). These results emphasize the importance of analyzing global and local factors in choice behavior and suggest avenues for the future development of sequential-choice models. PMID:23205915

Report on Activities and Programs for Countering Proliferation and NBC Terrorism. Volume 1, Executive Summary, Addendum to 2011 Report

DTIC Science & Technology

2013-06-01

Executive Branch report on research , development, and acquisition (RDA) programs to Combat Weapons of Mass Destruction (WMD). Other interagency committees...characterize, secure, disable , and/or destroy a state or non-state actor’s WMD programs and related capabilities in hostile or uncertain environments. Threat...special operations, and security operations to defend against conventionally and unconventionally delivered WMD. WMD Consequence Management. Actions

Strategic Positioning of United States Air Force Civil Engineer Contingency Equipment within the Supply Chain

DTIC Science & Technology

2014-03-27

discussed. Background In a dynamic world full of uncertain threats, the United States military is constantly required to evolve and enhance its...capabilities to effectively defend the nation. One of the military capabilities requiring continuous improvement to ensure pursuit of American...force the right personnel, equipment, and supplies in the right place, at the right time, and in the right quantity, across the full range of military

Where We Are Now

ERIC Educational Resources Information Center

Guth, Douglas J.

2017-01-01

In 2012, the American Association of Community Colleges (AACC) released a report stating, in no uncertain terms, that "the American dream is imperiled." Data supporting this declaration highlighted a sagging economy and a record number of Americans who had fallen into poverty. A product of the 21st-Century Commission on the Future of…

Altered humin compositions under organic and inorganic fertilization on an intensively cultivated sandy loam soil

USDA-ARS?s Scientific Manuscript database

Humin is the largest and also the least understood fraction of soil organic matter. The humin structure and its correlation with microbiological properties are particularly uncertain. We applied advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to investigate the structural chan...

Does Mother Nature Really Sell Margarine?: The Uncertain Rural Future.

ERIC Educational Resources Information Center

Schwartz, Peter

There exists a question as to whether United States society and its agricultural system will continue to follow the long-term trend of Western civilization or move in a new direction. The "modernization trend" of Western civilization has 4 components: scientification of knowledge, secularization of human values, industrialization of…

School Reform: Past and Present.

ERIC Educational Resources Information Center

Parker, Franklin

United States educational history is full of uncertain reform attempts beginning with colonial New England's school reform goal of salvation in this world as a preparation for eternal life in the next. A more practical type of education characterized the Early National Period. Monitorial schools and communal schools, as in New Harmony, Indiana,…

Long-term thinning alters ponderosa pine reproduction in northern Arizona

Treesearch

Kelsey N. Flathers; Thomas E. Kolb; John B. Bradford; Kristen M. Waring; W. Keith Moser

2016-01-01

The future of ponderosa pine (Pinus ponderosa var. scopulorum) forests in the southwestern United States is uncertain because climate-change-induced stresses are expected to increase tree mortality and place greater constraints on regeneration. Silvicultural treatments, which include thinning, are increasingly being used to address forest health concerns by...

Funding the Plan: Integration of Strategic Planning and Resource Allocation

ERIC Educational Resources Information Center

Pagel, Richard T.

2011-01-01

California Community Colleges are facing increased accountability while at the same time experiencing reduced and uncertain state funding. When resources are not properly allocated there is waste, public criticism, and ultimately increased oversight. A review of the Accrediting Commission for Community and Junior Colleges (ACCJC) sanction letters…

Sustainable lettuce: Adaptability to uncertain production conditions

USDA-ARS?s Scientific Manuscript database

Lettuce is a popular and widely consumed leafy vegetable. California and Arizona annually produce more than 250,000 acres of iceberg, romaine, leaf, and specialty types of lettuce, supplying more than 95% of the U.S market as well as exports to Canada and other countries. These states have dominat...

Introducing a buddying scheme for first year pre-registration students.

PubMed

Campbell, Anne

Student buddying schemes have been found to be helpful for a variety of different university students. This article describes a scheme where first year pre-registration child nursing students are buddied with second-year students, which was first initiated in the academic year 2012/2013. The first year students were aware that peer support was available but contact was only maintained by a minority of students. At present it is uncertain what impact the scheme has had on attrition figures, particularly in the first year. Initial evaluation indicates that students found the scheme helpful and would like it to continue to be available to first-year students.

Kernel-based least squares policy iteration for reinforcement learning.

PubMed

Xu, Xin; Hu, Dewen; Lu, Xicheng

2007-07-01

In this paper, we present a kernel-based least squares policy iteration (KLSPI) algorithm for reinforcement learning (RL) in large or continuous state spaces, which can be used to realize adaptive feedback control of uncertain dynamic systems. By using KLSPI, near-optimal control policies can be obtained without much a priori knowledge on dynamic models of control plants. In KLSPI, Mercer kernels are used in the policy evaluation of a policy iteration process, where a new kernel-based least squares temporal-difference algorithm called KLSTD-Q is proposed for efficient policy evaluation. To keep the sparsity and improve the generalization ability of KLSTD-Q solutions, a kernel sparsification procedure based on approximate linear dependency (ALD) is performed. Compared to the previous works on approximate RL methods, KLSPI makes two progresses to eliminate the main difficulties of existing results. One is the better convergence and (near) optimality guarantee by using the KLSTD-Q algorithm for policy evaluation with high precision. The other is the automatic feature selection using the ALD-based kernel sparsification. Therefore, the KLSPI algorithm provides a general RL method with generalization performance and convergence guarantee for large-scale Markov decision problems (MDPs). Experimental results on a typical RL task for a stochastic chain problem demonstrate that KLSPI can consistently achieve better learning efficiency and policy quality than the previous least squares policy iteration (LSPI) algorithm. Furthermore, the KLSPI method was also evaluated on two nonlinear feedback control problems, including a ship heading control problem and the swing up control of a double-link underactuated pendulum called acrobot. Simulation results illustrate that the proposed method can optimize controller performance using little a priori information of uncertain dynamic systems. It is also demonstrated that KLSPI can be applied to online learning control by incorporating an initial controller to ensure online performance.

Causal uncertainty, claimed and behavioural self-handicapping.

PubMed

Thompson, Ted; Hepburn, Jonathan

2003-06-01

Causal uncertainty beliefs involve doubts about the causes of events, and arise as a consequence of non-contingent evaluative feedback: feedback that leaves the individual uncertain about the causes of his or her achievement outcomes. Individuals high in causal uncertainty are frequently unable to confidently attribute their achievement outcomes, experience anxiety in achievement situations and as a consequence are likely to engage in self-handicapping behaviour. Accordingly, we sought to establish links between trait causal uncertainty, claimed and behavioural self-handicapping. Participants were N=72 undergraduate students divided equally between high and low causally uncertain groups. We used a 2 (causal uncertainty status: high, low) x 3 (performance feedback condition: success, non-contingent success, non-contingent failure) between-subjects factorial design to examine the effects of causal uncertainty on achievement behaviour. Following performance feedback, participants completed 20 single-solution anagrams and 12 remote associate tasks serving as performance measures, and 16 unicursal tasks to assess practice effort. Participants also completed measures of claimed handicaps, state anxiety and attributions. Relative to low causally uncertain participants, high causally uncertain participants claimed more handicaps prior to performance on the anagrams and remote associates, reported higher anxiety, attributed their failure to internal, stable factors, and reduced practice effort on the unicursal tasks, evident in fewer unicursal tasks solved. These findings confirm links between trait causal uncertainty and claimed and behavioural self-handicapping, highlighting the need for educators to facilitate means by which students can achieve surety in the manner in which they attribute the causes of their achievement outcomes.

Initial uncertainty in Pavlovian reward prediction persistently elevates incentive salience and extends sign-tracking to normally unattractive cues.

PubMed

Robinson, Mike J F; Anselme, Patrick; Fischer, Adam M; Berridge, Kent C

2014-06-01

Uncertainty is a component of many gambling games and may play a role in incentive motivation and cue attraction. Uncertainty can increase the attractiveness for predictors of reward in the Pavlovian procedure of autoshaping, visible as enhanced sign-tracking (or approach and nibbles) by rats of a metal lever whose sudden appearance acts as a conditioned stimulus (CS+) to predict sucrose pellets as an unconditioned stimulus (UCS). Here we examined how reward uncertainty might enhance incentive salience as sign-tracking both in intensity and by broadening the range of attractive CS+s. We also examined whether initially induced uncertainty enhancements of CS+ attraction can endure beyond uncertainty itself, and persist even when Pavlovian prediction becomes 100% certain. Our results show that uncertainty can broaden incentive salience attribution to make CS cues attractive that would otherwise not be (either because they are too distal from reward or too risky to normally attract sign-tracking). In addition, uncertainty enhancement of CS+ incentive salience, once induced by initial exposure, persisted even when Pavlovian CS-UCS correlations later rose toward 100% certainty in prediction. Persistence suggests an enduring incentive motivation enhancement potentially relevant to gambling, which in some ways resembles incentive-sensitization. Higher motivation to uncertain CS+s leads to more potent attraction to these cues when they predict the delivery of uncertain rewards. In humans, those cues might possibly include the sights and sounds associated with gambling, which contribute a major component of the play immersion experienced by problematic gamblers. Copyright © 2014 Elsevier B.V. All rights reserved.

Initial uncertainty in Pavlovian reward prediction persistently elevates incentive salience and extends sign-tracking to normally unattractive cues

PubMed Central

Robinson, Mike J. F.; Anselme, Patrick; Fischer, Adam M.; Berridge, Kent C.

2014-01-01

Uncertainty is a component of many gambling games and may play a role in incentive motivation and cue attraction. Uncertainty can increase the attractiveness for predictors of reward in the Pavlovian procedure of autoshaping, visible as enhanced sign-tracking (or approach and nibbles) by rats of a metal lever whose sudden appearance acts as a conditioned stimulus (CS+) to predict sucrose pellets as an unconditioned stimulus (UCS). Here we examined how reward uncertainty might enhance incentive salience as sign-tracking both in intensity and by broadening the range of attractive CS+s. We also examined whether initially-induced uncertainty enhancements of CS+ attraction can endure beyond uncertainty itself, and persist even when Pavlovian prediction becomes 100% certain. Our results show that uncertainty can broaden incentive salience attribution to make CS cues attractive that would otherwise not be (either because they are too distal from reward or too risky to normally attract sign-tracking). In addition, uncertainty enhancement of CS+ incentive salience, once induced by initial exposure, persisted even when Pavlovian CS-UCS correlations later rose toward 100% certainty in prediction. Persistence suggests an enduring incentive motivation enhancement potentially relevant to gambling, which in some ways resembles incentive-sensitization. Higher motivation to uncertain CS+s leads to more potent attraction to these cues when they predict the delivery of uncertain rewards. In humans, those cues might possibly include the sights and sounds associated with gambling, which contribute a major component of the play immersion experienced by problematic gamblers. PMID:24631397

Stochastic Forecasting of Algae Blooms in Lakes

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

Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

We consider the development of harmful algae blooms (HABs) in a lake with uncertain nutrients inflow. Two general frameworks, Fokker-Planck equation and the PDF methods, are developed to quantify the resultant concentration uncertainty of various algae groups, via deriving a deterministic equation of their joint probability density function (PDF). A computational example is examined to study the evolution of cyanobacteria (the blue-green algae) and the impacts of initial concentration and inflow-outflow ratio.

Mutually Assured Deletion: The Uncertain Future of Mass Destruction In Cyberspace

DTIC Science & Technology

2013-06-01

an indelible impression on practitioners and prognosticators alike. Its integration was initially quiet, seeping into the collective consciousness ...rivals anything before witnessed in the history of warfare, a “ quantum leap forward in the level of threat.” 1 Like a wolf in sheep’s clothing, cyber...tendency toward consistency often leads to neglect ( consciously or not) of stimuli that do not fit pre-existing notions.32 Analogies, then, and

Buckling of structures with uncertain imperfections - Personal perspective

NASA Technical Reports Server (NTRS)

Elishakoff, Isaac

1998-01-01

The previous review on stochastic buckling of structures was written by Amazigo in 1976. This review summarizes some of the developments which took place in recent two decades. A brief overview is given of the effect on uncertainty in the initial geometric imperfections, elastic moduli, applied forces, and thickness variation. For the benefit of the thinking reader, the review has a critical nature. It should be noted that this manuscript has yet to be completed.

Mixed-Initiative Human-Robot Interaction: Definition, Taxonomy, and Survey

DTIC Science & Technology

2015-01-01

response situations (i.e., harmful for human lives) that range from natural disasters (e.g., Fukushima nuclear plant meltdown [1]) to terrorist attacks... Fukushima Daiichi Nuclear Power Plants using mobile rescue robots," Journal of Field Robotics, vol. 30, pp. 44-63, 2013. [2] A. Davids, "Urban search...operating environment can be uncertain, unstructured, and hostile. The damaged Fukushima nuclear plant‟s high radiation level not only posed danger to

Feasibility of Mind-Body Intervention to Promote Wellness in Injured Soldiers

DTIC Science & Technology

2012-11-06

feeling tired or low energy (78.3%), nausea (69.57%) and headaches (69.57%). The most frequent symptoms endorsed as “bothered a lot” included trouble...sleeping (n=10); feeling tired (n=10), pain in arms, legs or joints (n=11), and headaches (n=11). Satisfaction. Seven participants completed the...totally new experience”. Their initial reactions included feeling skeptical (002,008, 022), finding it challenging (009, 016, 017), feeling uncertain

Fuzzy adaptive strong tracking scaled unscented Kalman filter for initial alignment of large misalignment angles

NASA Astrophysics Data System (ADS)

Li, Jing; Song, Ningfang; Yang, Gongliu; Jiang, Rui

2016-07-01

In the initial alignment process of strapdown inertial navigation system (SINS), large misalignment angles always bring nonlinear problem, which can usually be processed using the scaled unscented Kalman filter (SUKF). In this paper, the problem of large misalignment angles in SINS alignment is further investigated, and the strong tracking scaled unscented Kalman filter (STSUKF) is proposed with fixed parameters to improve convergence speed, while these parameters are artificially constructed and uncertain in real application. To further improve the alignment stability and reduce the parameters selection, this paper proposes a fuzzy adaptive strategy combined with STSUKF (FUZZY-STSUKF). As a result, initial alignment scheme of large misalignment angles based on FUZZY-STSUKF is designed and verified by simulations and turntable experiment. The results show that the scheme improves the accuracy and convergence speed of SINS initial alignment compared with those based on SUKF and STSUKF.

Forecasting seasonal influenza with a state-space SIR model

DOE PAGES

Osthus, Dave; Hickmann, Kyle S.; Caragea, Petruţa C.; ...

2017-04-08

Seasonal influenza is a serious public health and societal problem due to its consequences resulting from absenteeism, hospitalizations, and deaths. The overall burden of influenza is captured by the Centers for Disease Control and Prevention’s influenza-like illness network, which provides invaluable information about the current incidence. This information is used to provide decision support regarding prevention and response efforts. Despite the relatively rich surveillance data and the recurrent nature of seasonal influenza, forecasting the timing and intensity of seasonal influenza in the U.S. remains challenging because the form of the disease transmission process is uncertain, the disease dynamics are onlymore » partially observed, and the public health observations are noisy. Fitting a probabilistic state-space model motivated by a deterministic mathematical model [a susceptible-infectious-recovered (SIR) model] is a promising approach for forecasting seasonal influenza while simultaneously accounting for multiple sources of uncertainty. A significant finding of this work is the importance of thoughtfully specifying the prior, as results critically depend on its specification. Our conditionally specified prior allows us to exploit known relationships between latent SIR initial conditions and parameters and functions of surveillance data. We demonstrate advantages of our approach relative to alternatives via a forecasting comparison using several forecast accuracy metrics.« less

Forecasting seasonal influenza with a state-space SIR model

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

Osthus, Dave; Hickmann, Kyle S.; Caragea, Petruţa C.

Seasonal influenza is a serious public health and societal problem due to its consequences resulting from absenteeism, hospitalizations, and deaths. The overall burden of influenza is captured by the Centers for Disease Control and Prevention’s influenza-like illness network, which provides invaluable information about the current incidence. This information is used to provide decision support regarding prevention and response efforts. Despite the relatively rich surveillance data and the recurrent nature of seasonal influenza, forecasting the timing and intensity of seasonal influenza in the U.S. remains challenging because the form of the disease transmission process is uncertain, the disease dynamics are onlymore » partially observed, and the public health observations are noisy. Fitting a probabilistic state-space model motivated by a deterministic mathematical model [a susceptible-infectious-recovered (SIR) model] is a promising approach for forecasting seasonal influenza while simultaneously accounting for multiple sources of uncertainty. A significant finding of this work is the importance of thoughtfully specifying the prior, as results critically depend on its specification. Our conditionally specified prior allows us to exploit known relationships between latent SIR initial conditions and parameters and functions of surveillance data. We demonstrate advantages of our approach relative to alternatives via a forecasting comparison using several forecast accuracy metrics.« less

The Mexican Social Security counterreform: pensions for profit.

PubMed

Laurell, A C

1999-01-01

The social security counterreform, initiated in 1997, forms part of the neoliberal reorganization of Mexican society. The reform implies a profound change in the guiding principles of social security, as the public model based on integrality, solidarity, and redistribution is replaced by a model based on private administration of funds and services, individualization of entitlement, and reduction of rights. Its economic purpose is to move social services and benefits into the direct sphere of private capital accumulation. Although these changes will involve the whole social security system--old-age and disability pensions, health care, child care, and workers' compensation--they are most immediately evident in the pension scheme. The pay-as-you-go scheme is being replaced by privately managed individual retirement accounts which especially favor the big financial groups. These groups are gaining control over huge amounts of capital, are authorized to charge a high commission, and run no financial risks. The privatization of the system requires decisive state intervention with a legal change and a sizable state subsidy (1 to 1.5 percent of GNP) over five decades. The supposed positive impact on economic growth and employment is uncertain. A review of the new law and of the estimates of future annuities reveals shrinking pension coverage and inadequate incomes from pensions.

Preconception management of thyroid dysfunction.

PubMed

Okosieme, Onyebuchi E; Khan, Ishrat; Taylor, Peter N

2018-04-29

Uncorrected thyroid dysfunction in pregnancy has well-recognized deleterious effects on foetal and maternal health. The early gestation period is one of the critical foetal vulnerability during which maternal thyroid dysfunction may have lasting repercussions. Accordingly, a pragmatic preconception strategy is key for ensuring optimal thyroid disease outcomes in pregnancy. Preconception planning in women with hypothyroidism should pre-empt and mirror the adaptive changes in the thyroid gland by careful levothyroxine dose adjustments to ensure adequate foetal thyroid hormone delivery in pregnancy. In hyperthyroidism, the goal of preconception therapy is to control hyperthyroidism while curtailing the unwanted side effects of foetal and maternal exposure to antithyroid drugs. Thus, pregnancy should be deferred until a stable euthyroid state is achieved, and definitive therapy with radioiodine or surgery should be considered in women with Graves' disease planning future pregnancy. Women with active disease who are imminently trying to conceive should be switched to propylthiouracil either preconception or at conception in order to minimize the risk of birth defects from carbimazole or methimazole exposure. Optimal strategies for women with borderline states of thyroid dysfunction namely subclinical hypothyroidism, isolated hypothyroxinaemia and thyroid autoimmunity remain uncertain due to the dearth of controlled interventional trials. Future trial designs should aspire to recruit and initiate therapy before conception or as early as possible in pregnancy. © 2018 John Wiley & Sons Ltd.

Multimodality Inferring of Human Cognitive States Based on Integration of Neuro-Fuzzy Network and Information Fusion Techniques

NASA Astrophysics Data System (ADS)

Yang, G.; Lin, Y.; Bhattacharya, P.

2007-12-01

To achieve an effective and safe operation on the machine system where the human interacts with the machine mutually, there is a need for the machine to understand the human state, especially cognitive state, when the human's operation task demands an intensive cognitive activity. Due to a well-known fact with the human being, a highly uncertain cognitive state and behavior as well as expressions or cues, the recent trend to infer the human state is to consider multimodality features of the human operator. In this paper, we present a method for multimodality inferring of human cognitive states by integrating neuro-fuzzy network and information fusion techniques. To demonstrate the effectiveness of this method, we take the driver fatigue detection as an example. The proposed method has, in particular, the following new features. First, human expressions are classified into four categories: (i) casual or contextual feature, (ii) contact feature, (iii) contactless feature, and (iv) performance feature. Second, the fuzzy neural network technique, in particular Takagi-Sugeno-Kang (TSK) model, is employed to cope with uncertain behaviors. Third, the sensor fusion technique, in particular ordered weighted aggregation (OWA), is integrated with the TSK model in such a way that cues are taken as inputs to the TSK model, and then the outputs of the TSK are fused by the OWA which gives outputs corresponding to particular cognitive states under interest (e.g., fatigue). We call this method TSK-OWA. Validation of the TSK-OWA, performed in the Northeastern University vehicle drive simulator, has shown that the proposed method is promising to be a general tool for human cognitive state inferring and a special tool for the driver fatigue detection.

The demand for health with uncertainty and insurance.

PubMed

Liljas, B

1998-04-01

This paper develops Michael Grossman's demand-for-health model by letting the depreciation rate depend upon the level of health, by letting the incidence and size of illness be uncertain and by investigating how the individual's demand for health would be affected by the introduction of insurance. Beside the more theoretical results, there are also some results with important policy implications. When formulating the hypothetical scenario in willingness to pay (WTP) studies it is important whether the individual believes that the level of health is uncertain or not. The existence of insurance could also affect the stated WTP amount. Taking this into account could therefore explain some of the differences in the WTP for seemingly identical health care programs in different countries or different areas in the same country.

19. Photocopy of photograph (source uncertain; probably Bucks County Historical ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Photocopy of photograph (source uncertain; probably Bucks County Historical Society) ca. 1916, photographer unknown SHOWING CONSTRUCTION ESSENTIALLY COMPLETED. MERCER'S CAPTION READS: 'ON SATURDAY EVENING, NOVEMBER 13th AT 5: 15 P.M. THE WORKMEN HAVING AT FIVE O'CLOCK FINISHED THE CONSTRUCTION OF THE NEW BUILDING OF THE MUSEUM OF THE BUCKS COUNTY HISTORICAL SOCIETY AT DOYLESTOWN, A BAND OF TRAVELLING MUSICIANS STOPPED UNASKED AT NO. 196 GREEN STREET OPPOSITE THE SOUTHEAST GABLE OF THE BUILDING AND I HEARD THEM PLAY THE GERMAN SONG SHOWN BELOW, TRANSLATED 'WE HAD BUILT A STATELY HOUSE, AND DEDICATED IT TO GOD, AGAINST RAIN, STORM AND DISASTER' I CALLED THEM BACK TO PLAY IT AGAIN, BUT THEY MISUNDERSTOOD ME AND WENT AWAY. HENRY C. MERCER' - Mercer Museum, Pine & Ashland Streets, Doylestown, Bucks County, PA

Multilateral Telecoordinated Control of Multiple Robots With Uncertain Kinematics.

PubMed

Zhai, Di-Hua; Xia, Yuanqing

2017-06-06

This paper addresses the telecoordinated control of multiple robots in the simultaneous presence of asymmetric time-varying delays, nonpassive external forces, and uncertain kinematics/dynamics. To achieve the control objective, a neuroadaptive controller with utilizing prescribed performance control and switching control technique is developed, where the basic idea is to employ the concept of motion synchronization in each pair of master-slave robots and among all slave robots. By using the multiple Lyapunov-Krasovskii functionals method, the state-independent input-to-output practical stability of the closed-loop system is established. Compared with the previous approaches, the new design is straightforward and easier to implement and is applicable to a wider area. Simulation results on three pairs of three degrees-of-freedom robots confirm the theoretical findings.

SOARCA Peach Bottom Atomic Power Station Long-Term Station Blackout Uncertainty Analysis: Knowledge Advancement.

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

Gauntt, Randall O.; Mattie, Patrick D.; Bixler, Nathan E.

2014-02-01

This paper describes the knowledge advancements from the uncertainty analysis for the State-of- the-Art Reactor Consequence Analyses (SOARCA) unmitigated long-term station blackout accident scenario at the Peach Bottom Atomic Power Station. This work assessed key MELCOR and MELCOR Accident Consequence Code System, Version 2 (MACCS2) modeling uncertainties in an integrated fashion to quantify the relative importance of each uncertain input on potential accident progression, radiological releases, and off-site consequences. This quantitative uncertainty analysis provides measures of the effects on consequences, of each of the selected uncertain parameters both individually and in interaction with other parameters. The results measure the modelmore » response (e.g., variance in the output) to uncertainty in the selected input. Investigation into the important uncertain parameters in turn yields insights into important phenomena for accident progression and off-site consequences. This uncertainty analysis confirmed the known importance of some parameters, such as failure rate of the Safety Relief Valve in accident progression modeling and the dry deposition velocity in off-site consequence modeling. The analysis also revealed some new insights, such as dependent effect of cesium chemical form for different accident progressions. (auth)« less

Education for Sustainable Development: Enhancing Climate Change Adaptation Expertise in Developing Countries

ERIC Educational Resources Information Center

Fahey, Shireen; Verstraten, Luke; Berry, Ashton J.

2016-01-01

This article presents the results of an innovative education capacity assessment and delivery project to promote sustainable development in large ocean states in the Western Indian Ocean (WIO) region. Science education can help prepare the present and coming generations for stability in an uncertain future. Limited financial, geographical and…

The Role of the Teacher in an Uncertain World.

ERIC Educational Resources Information Center

Shapiro, Leo J.; Rodin, Mimi

This paper presents the results of a series of surveys designed to determine the attitudes of parents of school-aged children and other adults toward schools and their children's future, with a view toward offering encouragement to beginning teachers. Cross sections of the population were sampled nationwide, throughout the state of Illinois, and…

Rationales for Indirect Speech: The Theory of the Strategic Speaker

ERIC Educational Resources Information Center

Lee, James J.; Pinker, Steven

2010-01-01

Speakers often do not state requests directly but employ innuendos such as "Would you like to see my etchings?" Though such indirectness seems puzzlingly inefficient, it can be explained by a theory of the "strategic speaker", who seeks plausible deniability when he or she is uncertain of whether the hearer is cooperative or…

Spatial patterns of development drive water use

Treesearch

G. M. Sanchez; J. W. Smith; A. Terando; G. Sun; R. K. Meentemeyer

2018-01-01

Water availability is becoming more uncertain as human populations grow, cities expand into rural regions and the climate changes. In this study, we examine the functional relationship between water use and the spatial patterns of developed land across the rapidly growing region of the southeastern United States. We quantified the spatial pattern of developed land...

Carbon sequestration and greenhouse gas fluxes in agriculture: Challenges and opportunities

USDA-ARS?s Scientific Manuscript database

Globally, agriculture accounts for 13.5% of GHG emissions. In the United States, agriculture is a small but significant component of the country’s and world’s GHG emissions. We are moving into an uncertain and changing climate pattern that could affect agriculture production, sea levels, and human h...

Have Intellectual Freedom and Privacy Questions? Help Is on the Way!

ERIC Educational Resources Information Center

Adams, Helen R.

2015-01-01

School librarians are experiencing upheaval and controversy in education today. They are coping with the implementation of (and battles over) the Common Core State Standards, the uncertain future of their jobs, and the rapidly changing nature of school libraries. Despite the flux and instability in education, the importance of intellectual freedom…

Beyond Jefferson: The Rhetoric of Meritocracy and the Funding of Public Education

ERIC Educational Resources Information Center

Nicholson, Barbara

2003-01-01

This article presents an excerpt of a declaration from the United States Department of Education's "Strategic Plan: 2002-2007." The declaration signifies in no uncertain terms that the battle waged by critics of alternative research methods continues, and is likely to intensify. The denigration of research methods which decline to adhere…

Teacher Preparation: Reforming the Uncertain Profession

ERIC Educational Resources Information Center

Duncan, Arne

2010-01-01

In this paper, the Arne Duncan, the United States Secretary of Education, discusses the need for a sea change in America's schools of education, and focuses on the need to improve teacher preparation programs. Many schools of education have provided high-quality preparation programs for aspiring teachers for years. In the last decade, many…

The Uncertain Connection: Free Trade and Rural Mexican Migration to the United States.

ERIC Educational Resources Information Center

Cornelius, Wayne A.; Martin, Philip L.

1993-01-01

Argues that it is easy to overestimate the additional emigration from rural Mexico that could occur as a result of North American Free Trade Agreement (NAFTA) related economic restructuring in Mexico. Four major reasons why Mexican emigration may not increase dramatically are suggested. Phase-in recommendations related to implementation are…

Trimming the Budget: How to Make the Cuts

ERIC Educational Resources Information Center

Cortner-Castro, Christy

2009-01-01

The fiscal problems of today's school districts are a reflection of the national economy. Taxpayers are struggling to make mortgage payments and are reluctant--or unwilling--to pass bonds and levies that will raise property taxes. Local, state, and federal grants have dwindled, and the effect of the education stimulus dollars is uncertain. The…

Student Expression: The Uncertain Future

ERIC Educational Resources Information Center

Bathon, Justin M.; McCarthy, Martha M.

2008-01-01

On June 25, 2007, the United States Supreme Court rendered its decision in "Morse v. Frederick", a long-awaited ruling regarding student speech in public schools. For nearly twenty years, the Supreme Court had been silent on the issue while lower courts attempted to apply the rules announced in previous Supreme Court decisions. It is…

From point-wise stress data to a continuous description of the 3D crustal in situ stress state

NASA Astrophysics Data System (ADS)

Heidbach, O.; Ziegler, M.; Reiter, K.; Hergert, T.

2017-12-01

The in situ stress is a key parameter for the safe and sustainable management of geo-reservoirs or storage of waste and energy in deep geological repositories. It is also an essential initial condition for thermo-hydro-mechanical (THM) models that investigate man-made induced processes e.g. seismicity due to fluid injection/extraction, reservoir depletion or storage of heat producing high-level radioactive waste. Without a reasonable assumption on the initial stress condition it is not possible to assess if a man-made process is pushing the system into a critical state or not. However, modelling the initial 3D stress state on reservoir scale is challenging since data are hardly available before drilling in the area of interest. This is in particular the case for the stress magnitude data which are a prerequisite for a reliable model calibration. Here, we present a multi-stage 3D geomechani­cal-numerical model approach to estimate for a reservoir-scale volume the 3D in situ stress state. First, we set up a large-scale model which is calibrated by stress data and use the modelled stress field subsequently to calibrate a small-scale model located within the large-scale model. The local model contains a significantly higher resolution representation of the subsurface geometry around boreholes of a projected geothermal power plant. This approach incorporates two models and is an alternative to the required trade-off between resolution, computational cost and calibration data which is inevitable for a single model; an extension to a three-stage approach would be straight forward. We exemplify the two-stage approach for the area around Munich in the German Molasse Basin. The results of the reservoir-scale model are presented in terms of values for slip tendency as a measure for the criticality of fault reactivation. The model results show that variations due to uncertainties in the input data are mainly introduced by the uncertain material properties and missing estimates for the magnitude of the maximum horizontal stress SHmax, needed for a more reliable model calibration. This leads to the conclusion that at this stage the model's reliability depends only on the amount and quality of input data records such as available stress information rather than on the modelling technique itself.

Stratigraphic response and mammalian dispersal during initial India-Asia collision: Evidence from the Ghazij Formation, Balochistan, Pakistan

NASA Astrophysics Data System (ADS)

Clyde, William C.; Khan, Intizar H.; Gingerich, Philip D.

2003-12-01

Initial continental collision between India and Asia is thought to have caused significant changes to global climate and biota, yet its timing and biogeographic consequences are uncertain. Structural and geophysical evidence indicates initial collision during the early Paleogene, but sedimentary evidence of this has been controversial owing to the intense deformation and metamorphism along the suture zone. Modern orders of mammals that appeared abruptly on northern continents coincident with the global warming event marking the Paleocene-Eocene boundary are hypothesized to have originated on the Indian subcontinent, but no relevant paleontological information has been available to test this idea. Here we present new paleomagnetic, sedimentologic, and paleontologic evidence to show that the lower Eocene Ghazij Formation of western Pakistan records continental sedimentation and mammalian dispersal associated with initial India-Asia collision. Our results are consistent with the initial collision occurring near the Paleocene-Eocene boundary, but modern orders of mammals appeared later in Indo-Pakistan and thus did not likely originate on the Indian subcontinent.

Comparison of surface freshwater fluxes from different climate forecasts produced through different ensemble generation schemes.

NASA Astrophysics Data System (ADS)

Romanova, Vanya; Hense, Andreas; Wahl, Sabrina; Brune, Sebastian; Baehr, Johanna

2016-04-01

The decadal variability and its predictability of the surface net freshwater fluxes is compared in a set of retrospective predictions, all using the same model setup, and only differing in the implemented ocean initialisation method and ensemble generation method. The basic aim is to deduce the differences between the initialization/ensemble generation methods in view of the uncertainty of the verifying observational data sets. The analysis will give an approximation of the uncertainties of the net freshwater fluxes, which up to now appear to be one of the most uncertain products in observational data and model outputs. All ensemble generation methods are implemented into the MPI-ESM earth system model in the framework of the ongoing MiKlip project (www.fona-miklip.de). Hindcast experiments are initialised annually between 2000-2004, and from each start year 10 ensemble members are initialized for 5 years each. Four different ensemble generation methods are compared: (i) a method based on the Anomaly Transform method (Romanova and Hense, 2015) in which the initial oceanic perturbations represent orthogonal and balanced anomaly structures in space and time and between the variables taken from a control run, (ii) one-day-lagged ocean states from the MPI-ESM-LR baseline system (iii) one-day-lagged of ocean and atmospheric states with preceding full-field nudging to re-analysis in both the atmospheric and the oceanic component of the system - the baseline one MPI-ESM-LR system, (iv) an Ensemble Kalman Filter (EnKF) implemented into oceanic part of MPI-ESM (Brune et al. 2015), assimilating monthly subsurface oceanic temperature and salinity (EN3) using the Parallel Data Assimilation Framework (PDAF). The hindcasts are evaluated probabilistically using fresh water flux data sets from four different reanalysis data sets: MERRA, NCEP-R1, GFDL ocean reanalysis and GECCO2. The assessments show no clear differences in the evaluations scores on regional scales. However, on the global scale the physically motivated methods (i) and (iv) provide probabilistic hindcasts with a consistently higher reliability than the lagged initialization methods (ii)/(iii) despite the large uncertainties in the verifying observations and in the simulations.

Probable Diagnosis of a Patient with Niemann-Pick Disease Type C: Managing Pitfalls of Exome Sequencing.

PubMed

Zeiger, William A; Jamal, Nasheed I; Scheuner, Maren T; Pittman, Patricia; Raymond, Kimiyo M; Morra, Massimo; Mishra, Shri K

2018-02-17

Here, we present a case of a 31-year-old man with progressive cognitive decline, ataxia, and dystonia. Extensive laboratory, radiographic, and targeted genetic studies over the course of several years failed to yield a diagnosis. Initial whole exome sequencing through a commercial laboratory identified several variants of uncertain significance; however, follow-up clinical examination and testing ruled each of these out. Eventually, repeat whole exome sequencing identified a known pathogenic intronic variant in the NPC1 gene (NM_000271.4, c.1554-1009G>A) and an additional heterozygous exonic variant of uncertain significance in the NPC1 gene (NM_000271.4, c.2524T>C). Follow-up biochemical testing was consistent with a diagnosis of probable Niemann-Pick disease Type C (NP-C). This case illustrates the potential of whole exome sequencing for diagnosing rare complex neurologic diseases. It also identifies several potential common pitfalls that must be navigated by clinicians when interpreting commercial whole exome sequencing results.

Adaptive critic designs for optimal control of uncertain nonlinear systems with unmatched interconnections.

PubMed

Yang, Xiong; He, Haibo

2018-05-26

In this paper, we develop a novel optimal control strategy for a class of uncertain nonlinear systems with unmatched interconnections. To begin with, we present a stabilizing feedback controller for the interconnected nonlinear systems by modifying an array of optimal control laws of auxiliary subsystems. We also prove that this feedback controller ensures a specified cost function to achieve optimality. Then, under the framework of adaptive critic designs, we use critic networks to solve the Hamilton-Jacobi-Bellman equations associated with auxiliary subsystem optimal control laws. The critic network weights are tuned through the gradient descent method combined with an additional stabilizing term. By using the newly established weight tuning rules, we no longer need the initial admissible control condition. In addition, we demonstrate that all signals in the closed-loop auxiliary subsystems are stable in the sense of uniform ultimate boundedness by using classic Lyapunov techniques. Finally, we provide an interconnected nonlinear plant to validate the present control scheme. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aerodynamic Levitation Reactor Studies of Fluorine Reactions with Refractory Ceramics

DTIC Science & Technology

1981-05-01

Melting Points of Rare-Earth Metals and Rare-Earth Trifluorides . 14 3. Aerodynamic Lavitation Flow Reactor. 15 4 Lanthanutm-Boron-Carbon Ternary Phase...the least volatile fluorides (CaF , SrT and rare-earth trifluorides ) would yield a 10% increase in w* (initially O.O cam) in about 1 hour at 1300K...measurement, and are, therefore, somewhat uncertain. The melting points of the rare-earth metals and their trifluorides are illustrated in Fig. 2. The melting

Defense Management: Actions Needed to Improve Management of Air Force’s Food Transformation Initiative

DTIC Science & Technology

2011-07-01

nonappropriated fund food and beverage operations, such as clubs and snack bars, accepted jobs with the new contractor, but their job security remains uncertain...operate the nonappropriated fund food and beverage operations, such as clubs and bowling center snack bars, because many of these facilities were...center and golf course snack bars and officers’ and enlisted members’ clubs, to Aramark in a commission-based contract.11 Table 1 lists the pilot

Percutaneous transhepatic vs. endoscopic retrograde biliary drainage for suspected malignant hilar obstruction: study protocol for a randomized controlled trial.

PubMed

Al-Kawas, Firas; Aslanian, Harry; Baillie, John; Banovac, Filip; Buscaglia, Jonathan M; Buxbaum, James; Chak, Amitabh; Chong, Bradford; Coté, Gregory A; Draganov, Peter V; Dua, Kulwinder; Durkalski, Valerie; Elmunzer, B Joseph; Foster, Lydia D; Gardner, Timothy B; Geller, Brian S; Jamidar, Priya; Jamil, Laith H; Keswani, Rajesh N; Khashab, Mouen A; Lang, Gabriel D; Law, Ryan; Lichtenstein, David; Lo, Simon K; McCarthy, Sean; Melo, Silvio; Mullady, Daniel; Nieto, Jose; Bayne Selby, J; Singh, Vikesh K; Spitzer, Rebecca L; Strife, Brian; Tarnaksy, Paul; Taylor, Jason R; Tokar, Jeffrey; Wang, Andrew Y; Williams, April; Willingham, Field; Yachimski, Patrick

2018-02-14

The optimal approach to the drainage of malignant obstruction at the liver hilum remains uncertain. We aim to compare percutaneous transhepatic biliary drainage (PTBD) to endoscopic retrograde cholangiography (ERC) as the first intervention in patients with cholestasis due to suspected malignant hilar obstruction (MHO). The INTERCPT trial is a multi-center, comparative effectiveness, randomized, superiority trial of PTBD vs. ERC for decompression of suspected MHO. One hundred and eighty-four eligible patients across medical centers in the United States, who provide informed consent, will be randomly assigned in 1:1 fashion via a web-based electronic randomization system to either ERC or PTBD as the initial drainage and, if indicated, diagnostic procedure. All subsequent clinical interventions, including crossover to the alternative procedure, will be dictated by treating physicians per usual clinical care. Enrolled subjects will be assessed for successful biliary drainage (primary outcome measure), adequate tissue diagnosis, adverse events, the need for additional procedures, hospitalizations, and oncological outcomes over a 6-month follow-up period. Subjects, treating clinicians and outcome assessors will not be blinded. The INTERCPT trial is designed to determine whether PTBD or ERC is the better initial approach when managing a patient with suspected MHO, a common clinical dilemma that has never been investigated in a randomized trial. ClinicalTrials.gov, Identifier: NCT03172832 . Registered on 1 June 2017.

Panic disorder with agoraphobia from a behavioral neuroscience perspective: Applying the research principles formulated by the Research Domain Criteria (RDoC) initiative.

PubMed

Hamm, Alfons O; Richter, Jan; Pané-Farré, Christiane; Westphal, Dorte; Wittchen, Hans-Ulrich; Vossbeck-Elsebusch, Anna N; Gerlach, Alexander L; Gloster, Andrew T; Ströhle, Andreas; Lang, Thomas; Kircher, Tilo; Gerdes, Antje B M; Alpers, Georg W; Reif, Andreas; Deckert, Jürgen

2016-03-01

In the current review, we reconceptualize a categorical diagnosis-panic disorder and agoraphobia-in terms of two constructs within the domain "negative valence systems" suggested by the Research Domain Criteria initiative. Panic attacks are considered as abrupt and intense fear responses to acute threat arising from inside the body, while anxious apprehension refers to anxiety responses to potential harm and more distant or uncertain threat. Taking a dimensional view, panic disorder with agoraphobia is defined with the threat-imminence model stating that defensive responses are dynamically organized along the dimension of the proximity of the threat. We tested this model within a large group of patients with panic disorder and agoraphobia (N = 369 and N = 124 in a replication sample) and found evidence that panic attacks are indeed instances of circa strike defense. This component of the defensive reactivity was related to genetic modulators within the serotonergic system. In contrast, anxious apprehension-characterized by attentive freezing during postencounter defense-was related to general distress and depressive mood, as well as to genetic modulations within the hypothalamic-pituitary-adrenal (HPA) axis. Patients with a strong behavioral tendency for active and passive avoidance responded better to exposure treatment if the therapist guides the patient through the exposure exercises. © 2016 Society for Psychophysiological Research.

Climate Change and Human Health Impacts in the United States: An Update on the Results of the U.S. National Assessment

PubMed Central

Ebi, Kristie L.; Mills, David M.; Smith, Joel B.; Grambsch, Anne

2006-01-01

The health sector component of the first U.S. National Assessment, published in 2000, synthesized the anticipated health impacts of climate variability and change for five categories of health outcomes: impacts attributable to temperature, extreme weather events (e.g., storms and floods), air pollution, water- and food-borne diseases, and vector- and rodent-borne diseases. The Health Sector Assessment (HSA) concluded that climate variability and change are likely to increase morbidity and mortality risks for several climate-sensitive health outcomes, with the net impact uncertain. The objective of this study was to update the first HSA based on recent publications that address the potential impacts of climate variability and change in the United States for the five health outcome categories. The literature published since the first HSA supports the initial conclusions, with new data refining quantitative exposure–response relationships for several health end points, particularly for extreme heat events and air pollution. The United States continues to have a very high capacity to plan for and respond to climate change, although relatively little progress has been noted in the literature on implementing adaptive strategies and measures. Large knowledge gaps remain, resulting in a substantial need for additional research to improve our understanding of how weather and climate, both directly and indirectly, can influence human health. Filling these knowledge gaps will help better define the potential health impacts of climate change and identify specific public health adaptations to increase resilience. PMID:16966082

The Value of Wind Technology Innovation: Implications for the U.S. Power System, Wind Industry, Electricity Consumers, and Environment

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

Mai, Trieu T; Lantz, Eric J; Mowers, Matthew

Improvements to wind technologies have, in part, led to substantial deployment of U.S. wind power in recent years. The degree to which technology innovation will continue is highly uncertain adding to uncertainties in future wind deployment. We apply electric sector modeling to estimate the potential wind deployment opportunities across a range of technology advancement projections. The suite of projections considered span a wide range of possible cost and technology innovation trajectories, including those from a recent expert elicitation of wind energy experts, a projection based on the broader literature, and one reflecting estimates based on a U.S. DOE research initiative.more » In addition, we explore how these deployment pathways may impact the electricity system, electricity consumers, the environment, and the wind-related workforce. Overall, our analysis finds that wind technology innovation can have consequential implications for future wind power development throughout the United States, impact the broader electricity system, lower electric system and consumer costs, provide potential environmental benefits, and grow the U.S. wind workforce.« less

Orbiting space debris: Dangers, measurement and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-06-01

Space debris is a growing environmental problem. Accumulation of objects in earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, United States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical and diplomatic components. Actions need to be taken now to: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the loss of critical space systems such as the space shuttle or the space station.

The Load of Lightning-induced Nitrogen Oxides and Its Impact on the Ground-level Ozone during Summertime over the Mountain West States

EPA Science Inventory

Lightning-induced nitrogen oxides (LNOX), in the presence of sunlight, volatile organic compounds and water, can be a relatively large but uncertain source for ozone (O3) and hydroxyl radical (OH) in the atmosphere. Using lightning flash data from the National Lightning Detection...

Behavior and sensitivity of an optimal tree diameter growth model under data uncertainty

Treesearch

Don C. Bragg

2005-01-01

Using loblolly pine, shortleaf pine, white oak, and northern red oak as examples, this paper considers the behavior of potential relative increment (PRI) models of optimal tree diameter growth under data uncertainity. Recommendations on intial sample size and the PRI iteractive curve fitting process are provided. Combining different state inventories prior to PRI model...

Vulnerability of forests of the Midwest and Northeast United States to climate change

Treesearch

Chris Swanston; Leslie A. Brandt; Maria K. Janowiak; Stephen D. Handler; Patricia Butler-Leopold; Louis Iverson; Frank R. Thompson; Todd A. Ontl; P. Danielle Shannon

2018-01-01

Forests of the Midwest and Northeast significantly define the character, culture, and economy of this large region but face an uncertain future as the climate continues to change. Forests vary widely across the region, and vulnerabilities are strongly influenced by regional differences in climate impacts and adaptive capacity. Not all forests are vulnerable; longer...

Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the southeast United States and co-benefit of SO2 emission controls

EPA Science Inventory

Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for...

Family forest owners rule!

Treesearch

Brett J. Butler

2011-01-01

The largest issues facing forests in the United States are no longer about public lands. The public still wants the same things envisioned by the Weeks Act—water protection, timber supply, aesthetics, and recreational opportunities (U.S. Forest Service 1913)—but the focus must now be on the lands whose fate is more uncertain. We have entered a new era...

Silvicultural decisionmaking in an uncertain climate future: a workshop-based exploration of considerations, strategies, and approaches

Treesearch

Maria K. Janowiak; Christopher W. Swanston; Linda M. Nagel; Christopher R. Webster; Brian J. Palik; Mark J. Twery; John B. Bradford; Linda R. Parker; Andrea T. Hille; Sheela M. Johnson

2011-01-01

Land managers across the country face the immense challenge of developing and applying appropriate management strategies as forests respond to climate change. We hosted a workshop to explore silvicultural strategies for addressing the uncertainties surrounding climate change and forest response in the northeastern and north-central United States. Outcomes of this...

Essential Not Optional: A Strategic Approach to Fund-Raising for Endowments

ERIC Educational Resources Information Center

Griswold, John S.; Jarvis, William F.

2012-01-01

This overview of the state of endowment giving comes at a time of urgent need in the nonprofit sector. With market returns uncertain, and spending restraint difficult, the moderate but measurable increase in donations in the previous year invites institutions to consider elevating fund-raising to a more strategic position within the organization.…

Analysis of the timber situation in Florida, 1995- 2025

Treesearch

Roger C. Conner; Raymond M. Sheffield

2005-01-01

The demand for wood fiber nationwide is expected to increase in the foreseeable future. Harvesting restrictions on forest lands in the West have increased pressure on the South's forest resources to provide more wood. The ability of Florida and other Southern States to respond is uncertain. The authors describe the current extent, condition, and availability of...

School Leaders Facing Real Change: Shifting Geography, Uncertain Paths

ERIC Educational Resources Information Center

Louis, Karen Seashore

2003-01-01

A central problem for school leadership in the United States is to create settings in which success for students motivates teachers. Meeting this objective is becoming more difficult as teachers, except the most brilliant, struggle to cope with the diversity of students in a changing socio-economic climate and a context in which there is a…

Prevalence of Diagnosed Tourette Syndrome in Persons Aged 6-17 Years--United States, 2007

ERIC Educational Resources Information Center

Centers for Disease Control and Prevention, 2009

2009-01-01

Tourette syndrome (TS) is an inheritable, childhood-onset neurologic disorder marked by persistent multiple motor tics and at least one vocal tic. Tics are involuntary, repetitive, stereotypic movements or vocalizations that are usually sudden and rapid and often can be suppressed for short periods. The prevalence of TS is uncertain; the broad…

Antioch College: A Celebrated History and an Uncertain Future

ERIC Educational Resources Information Center

Hayford, Elizabeth R.

2011-01-01

On June 7, 2007, the Antioch University board of trustees declared that Antioch College, an independent liberal arts college in Yellow Springs, Ohio, was in a state of financial exigency, and, two days later, voted to suspend college operations after the next academic year. After that year, the board oversaw the closing of the college while…

Blocked Paths, Uncertain Futures: The Postsecondary Education and Labor Market Prospects of Undocumented Latino Youth

ERIC Educational Resources Information Center

Abrego, Leisy J.; Gonzales, Roberto G.

2010-01-01

Over the past few decades, undocumented settlement in the United States has grown to unprecedented numbers. Among the nearly 12 million undocumented immigrants, a substantial portion of undocumented youth is growing up with legal access to public education through high school but facing legal restrictions and economic barriers to higher education…

Does intolerance of uncertainty predict anticipatory startle responses to uncertain threat?

PubMed

Nelson, Brady D; Shankman, Stewart A

2011-08-01

Intolerance of uncertainty (IU) has been proposed to be an important maintaining factor in several anxiety disorders, including generalized anxiety disorder, obsessive-compulsive disorder, and social phobia. While IU has been shown to predict subjective ratings and decision-making during uncertain/ambiguous situations, few studies have examined whether IU also predicts emotional responding to uncertain threat. The present study examined whether IU predicted aversive responding (startle and subjective ratings) during the anticipation of temporally uncertain shocks. Sixty-nine participants completed three experimental conditions during which they received: no shocks, temporally certain/predictable shocks, and temporally uncertain shocks. Results indicated that IU was negatively associated with startle during the uncertain threat condition in that those with higher IU had a smaller startle response. IU was also only related to startle during the uncertain (and not the certain/predictable) threat condition, suggesting that it was not predictive of general aversive responding, but specific to responses to uncertain aversiveness. Perceived control over anxiety-related events mediated the relation between IU and startle to uncertain threat, such that high IU led to lowered perceived control, which in turn led to a smaller startle response. We discuss several potential explanations for these findings, including the inhibitory qualities of IU. Overall, our results suggest that IU is associated with attenuated aversive responding to uncertain threat. Copyright © 2011 Elsevier B.V. All rights reserved.

Cerulean Warbler Occurrence Atlas for Military Installations

DTIC Science & Technology

2010-04-01

Army Ammuniton Plant (Closed) IN NO 2009 Army IOWA ARMY AMMUNITION PLANT IA UNCERTAIN 2009 USACE J. Percy Priest Lake TN UNCERTAIN 2009 USACE J...Stonewall Jackson Lake WV UNCERTAIN 2009 USACE Summersville Lake WV no POC Army Sunflower Army Ammunition Plant KS no POC USACE Sutton Lake WV UNCERTAIN

Assessing the near-term risk of climate uncertainty : interdependencies among the U.S. states.

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

Loose, Verne W.; Lowry, Thomas Stephen; Malczynski, Leonard A.

2010-04-01

Policy makers will most likely need to make decisions about climate policy before climate scientists have resolved all relevant uncertainties about the impacts of climate change. This study demonstrates a risk-assessment methodology for evaluating uncertain future climatic conditions. We estimate the impacts of climate change on U.S. state- and national-level economic activity from 2010 to 2050. To understand the implications of uncertainty on risk and to provide a near-term rationale for policy interventions to mitigate the course of climate change, we focus on precipitation, one of the most uncertain aspects of future climate change. We use results of the climate-modelmore » ensemble from the Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report 4 (AR4) as a proxy for representing climate uncertainty over the next 40 years, map the simulated weather from the climate models hydrologically to the county level to determine the physical consequences on economic activity at the state level, and perform a detailed 70-industry analysis of economic impacts among the interacting lower-48 states. We determine the industry-level contribution to the gross domestic product and employment impacts at the state level, as well as interstate population migration, effects on personal income, and consequences for the U.S. trade balance. We show that the mean or average risk of damage to the U.S. economy from climate change, at the national level, is on the order of $1 trillion over the next 40 years, with losses in employment equivalent to nearly 7 million full-time jobs.« less

Preparing Capable Decision Makers for an Uncertain Future within Underdeveloped, Degraded and Denied Operational Environments

DTIC Science & Technology

2013-06-01

later in life’ (post primary education ) development effort, but also one which should – nea must – be initiated quite early. This might actually be...and thinker, Thomas Hobbes. (Interestingly, Hobbes apparently was the source for the tiger’s name within the comic strip ‘Calvin and Hobbes’; while...BROAD-BASED EDUCATION – T. HOBBES’ PHILOSOPHIES SCIENCE, that is, Kno wledg e of Con se- qu en ces ; which is called also PHILO- SOPHY Con seq uences

Army Logistician. Volume 40, Issue 3, May-June 2008

DTIC Science & Technology

2008-06-01

accessible only with a common access card to mitigate security concerns. A link to the “Unit Special Products” site should be a standard fixture...out how to work it. Initially, she was a little uncertain about how to use it or the accompanying soft- ware, iTunes . But she slowly started to...explore both the iPod and iTunes , and, surprisingly, within a few hours, she was confidently rocking out and downloading music! How did she do it

USAF 1990 Research Initiation Program. Volume 3

DTIC Science & Technology

1992-06-25

the reinforcement outward, both on the entrance and exit sides. The reinforcement was bent outward like a membrane under internal prressure. This led...potential of a neuron. C: cell capacitance. R: membrane resistance. w: synaptic weight. h(x): sigmoidal function describing the firing rate. y: external...Proof: The uncertain closed loop plant may be written as x(t)=(A+AA)x(t)+(Ao+ AAo )x(t-T) (B+AB)F(C AC)x(t) =(A+BFC)x(t)+(AA+ABFC+BFAC+ABFAC)x(t)+(Ao+Ao)X(t

Influence of uncertain identification of triggering rainfall on the assessment of landslide early warning thresholds

NASA Astrophysics Data System (ADS)

Peres, David J.; Cancelliere, Antonino; Greco, Roberto; Bogaard, Thom A.

2018-03-01

Uncertainty in rainfall datasets and landslide inventories is known to have negative impacts on the assessment of landslide-triggering thresholds. In this paper, we perform a quantitative analysis of the impacts of uncertain knowledge of landslide initiation instants on the assessment of rainfall intensity-duration landslide early warning thresholds. The analysis is based on a synthetic database of rainfall and landslide information, generated by coupling a stochastic rainfall generator and a physically based hydrological and slope stability model, and is therefore error-free in terms of knowledge of triggering instants. This dataset is then perturbed according to hypothetical reporting scenarios that allow simulation of possible errors in landslide-triggering instants as retrieved from historical archives. The impact of these errors is analysed jointly using different criteria to single out rainfall events from a continuous series and two typical temporal aggregations of rainfall (hourly and daily). The analysis shows that the impacts of the above uncertainty sources can be significant, especially when errors exceed 1 day or the actual instants follow the erroneous ones. Errors generally lead to underestimated thresholds, i.e. lower than those that would be obtained from an error-free dataset. Potentially, the amount of the underestimation can be enough to induce an excessive number of false positives, hence limiting possible landslide mitigation benefits. Moreover, the uncertain knowledge of triggering rainfall limits the possibility to set up links between thresholds and physio-geographical factors.

Communicating uncertainty in hydrological forecasts: mission impossible?

NASA Astrophysics Data System (ADS)

Ramos, Maria-Helena; Mathevet, Thibault; Thielen, Jutta; Pappenberger, Florian

2010-05-01

Cascading uncertainty in meteo-hydrological modelling chains for forecasting and integrated flood risk assessment is an essential step to improve the quality of hydrological forecasts. Although the best methodology to quantify the total predictive uncertainty in hydrology is still debated, there is a common agreement that one must avoid uncertainty misrepresentation and miscommunication, as well as misinterpretation of information by users. Several recent studies point out that uncertainty, when properly explained and defined, is no longer unwelcome among emergence response organizations, users of flood risk information and the general public. However, efficient communication of uncertain hydro-meteorological forecasts is far from being a resolved issue. This study focuses on the interpretation and communication of uncertain hydrological forecasts based on (uncertain) meteorological forecasts and (uncertain) rainfall-runoff modelling approaches to decision-makers such as operational hydrologists and water managers in charge of flood warning and scenario-based reservoir operation. An overview of the typical flow of uncertainties and risk-based decisions in hydrological forecasting systems is presented. The challenges related to the extraction of meaningful information from probabilistic forecasts and the test of its usefulness in assisting operational flood forecasting are illustrated with the help of two case-studies: 1) a study on the use and communication of probabilistic flood forecasting within the European Flood Alert System; 2) a case-study on the use of probabilistic forecasts by operational forecasters from the hydroelectricity company EDF in France. These examples show that attention must be paid to initiatives that promote or reinforce the active participation of expert forecasters in the forecasting chain. The practice of face-to-face forecast briefings, focusing on sharing how forecasters interpret, describe and perceive the model output forecasted scenarios, is essential. We believe that the efficient communication of uncertainty in hydro-meteorological forecasts is not a mission impossible. Questions remaining unanswered in probabilistic hydrological forecasting should not neutralize the goal of such a mission, and the suspense kept should instead act as a catalyst for overcoming the remaining challenges.

Global sensitivity analysis in stochastic simulators of uncertain reaction networks.

PubMed

Navarro Jimenez, M; Le Maître, O P; Knio, O M

2016-12-28

Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol's decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes that the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. A sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.

Global sensitivity analysis in stochastic simulators of uncertain reaction networks

DOE PAGES

Navarro Jimenez, M.; Le Maître, O. P.; Knio, O. M.

2016-12-23

Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol’s decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes thatmore » the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. Here, a sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.« less

Likelihood of achieving air quality targets under model uncertainties.

PubMed

Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

2011-01-01

Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses.

Global sensitivity analysis in stochastic simulators of uncertain reaction networks

NASA Astrophysics Data System (ADS)

Navarro Jimenez, M.; Le Maître, O. P.; Knio, O. M.

2016-12-01

Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol's decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes that the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. A sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.

The Summer Food Service Program and the Ongoing Hunger Crisis in Mississippi.

PubMed

Cobern, Jade A; Shell, Kathryn J; Henderson, Everett R; Beech, Bettina M; Batlivala, Sarosh P

2015-10-01

Food insecurity is simply defined as uncertain access to adequate food. Nearly 50 million Americans, 16 million of whom are children, are food insecure. Mississippi has 21% food insecure citizens, and has the most food insecure county in the nation. Our state's school system's National Breakfast and Lunch Programs help combat food insecurity, but a gap still exists. This gap widens during the summer. In this paper, we describe the Mississippi Summer Food Service Program. While the program has had success in our state, it still faces challenges. Organized action by physicians in Mississippi and the Mississippi State Medical Association could significantly increase participation in these programs that are vital to our state.

Strategic Defense Initiative Organization adaptive structures program overview

NASA Astrophysics Data System (ADS)

Obal, Michael; Sater, Janet M.

In the currently envisioned architecture none of the Strategic Defense System (SDS) elements to be deployed will receive scheduled maintenance. Assessments of performance capability due to changes caused by the uncertain effects of environments will be difficult, at best. In addition, the system will have limited ability to adjust in order to maintain its required performance levels. The Materials and Structures Office of the Strategic Defense Initiative Organization (SDIO) has begun to address solutions to these potential difficulties via an adaptive structures technology program that combines health and environment monitoring with static and dynamic structural control. Conceivable system benefits include improved target tracking and hit-to-kill performance, on-orbit system health monitoring and reporting, and threat attack warning and assessment.

Examining Law & Policy for Undocumented Immigrant Students through the PK-20 Pipeline. Equity by Design

ERIC Educational Resources Information Center

Nguyen, David H. K.

2017-01-01

The purpose of this Equity Brief is to provide some guidance for educators with regard to the challenges around supporting undocumented students in the midst of uncertain times and continued concerns surrounding Deferred Action for Childhood Arrivals (DACA). Many youth in the DACA Program have made the United States their home and have lived in…

76 FR 14069 - Notice of Inventory Completion: Office of the State Archaeologist, Michigan Historical Center...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

... mid-19th century Supervisor's House, a historic building in the park. In 2001, one additional bone was... House. It is uncertain if these remains are from the same individual, but the single additional bone may... that the 1986 fragments and 2001 bone belong to one individual. No known individual was identified. No...

Preparing for the '90s: Thrust for Quality in Higher Education [and] Thrust for Quality in Public Schools.

ERIC Educational Resources Information Center

Louisiana Association of Businss and Industry, Baton Rouge.

Examined in the first report is the need for educational improvement in higher education in Louisiana. Discussion focuses on the state of the economy: half of Louisiana's economy (production and manufacturing) is in decline, while the other half (production jobs) is uncertain. Cooperation between higher education and business offers hope for the…

Developmental Education and Student Debt: Remediation's Uncertain Impact on Financial and Academic Outcomes. Research Report

ERIC Educational Resources Information Center

Fernandez, Chris; Barone, Sandra; Klepfer, Kasey

2014-01-01

Developmental education is integral to higher education in the United States. In academic year (AY) 2011-12, about one-third of all first-year undergraduates and 40 percent of first-year community college students were enrolled in at least one developmental course (NPSAS:12). Generally, students who fail to achieve adequate scores on placement…

The Inconsistent Past and Uncertain Future of Human Rights Education in the United States

ERIC Educational Resources Information Center

Sirota, Sandra

2017-01-01

This article examines how the U.S. government's stance on human rights and human rights education has shifted from leading the creation of the 1948 Universal Declaration of Human Rights through the United Nations Human Rights Commission, with Eleanor Roosevelt as chair of the Commission, to one in which human rights education has only a minimal…

Non-industrial private forests: timber supply for an uncertain future.

Treesearch

Ralph J. Alig

1990-01-01

According to U.S. Forest Service estimates (in press), annual timber harvest volume in the United States will have to increase from the 18 billion cubic feet of 1986 to 27 billion cubic feet by 2040 to satisfy increasing demand (Figure 1). It's doubtful that public forest lands can provide much of this additional timber, primarily because of increasing calls for...

What Employers Need to Know: Frequently Asked Questions about High School Students in Workplaces

ERIC Educational Resources Information Center

Jobs For the Future, 2015

2015-01-01

Employers may not know the best way to reach out or how to structure opportunities for young people to explore careers within their organization. In addition, employers may be uncertain about liability, privacy policies, and safety regulations for employees under the age of 18. State and federal laws and policies pertaining to youth employment can…

Thoughts and Speculations on the Possible Decline of Higher Education in the United States.

ERIC Educational Resources Information Center

Corso, Emanuele

The future of higher education is more uncertain now than it has ever been and it is interesting to examine and speculate as to causes and possible results. Values and sanctions that have previously motivated unquestioned acceptance of the legitimacy of higher education are, like many other values and sanctions in our society, presently undergoing…

A Study of Late Funding of Elementary and Secondary Education Programs. Final Report.

ERIC Educational Resources Information Center

Peat, Marwick, Mitchell and Co., Washington, DC.

This publication presents findings of a nationwide study of the impact of late or uncertain funding on elementary secondary educational programs funded by the U.S. Office of Education (USOE). Emphasis of the report is on detailed documentation of the problems created by current funding flow patterns to state and local education agencies. In phase…

My Attitudes toward Science (MATS): The Development of a Multidimensional Instrument Measuring Students' Science Attitudes

ERIC Educational Resources Information Center

Hillman, Susan J.; Zeeman, Stephan I.; Tilburg, Charles E.; List, Henrietta E.

2016-01-01

The number of students in the United States choosing science, technology, engineering or mathematics careers is declining at a time when demand for these occupations is rapidly increasing. Numerous efforts have been undertaken to reverse this trend, yet results are uncertain. One's attitude is key to many choices one makes, and this includes, for…

How to Assess the Real Payoff of a College Degree

ERIC Educational Resources Information Center

Carlson, Scott

2013-01-01

Just listen to Dimitrius Graham sing. As a music major at Morgan State University, he seems keenly aware of certain realities about his life: His talent is undeniable and probably innate, and his future is promising but uncertain. He could make a career singing on Broadway or climbing the charts as a Billboard phenomenon. Because he went to…

A set-theoretic model reference adaptive control architecture for disturbance rejection and uncertainty suppression with strict performance guarantees

NASA Astrophysics Data System (ADS)

Arabi, Ehsan; Gruenwald, Benjamin C.; Yucelen, Tansel; Nguyen, Nhan T.

2018-05-01

Research in adaptive control algorithms for safety-critical applications is primarily motivated by the fact that these algorithms have the capability to suppress the effects of adverse conditions resulting from exogenous disturbances, imperfect dynamical system modelling, degraded modes of operation, and changes in system dynamics. Although government and industry agree on the potential of these algorithms in providing safety and reducing vehicle development costs, a major issue is the inability to achieve a-priori, user-defined performance guarantees with adaptive control algorithms. In this paper, a new model reference adaptive control architecture for uncertain dynamical systems is presented to address disturbance rejection and uncertainty suppression. The proposed framework is predicated on a set-theoretic adaptive controller construction using generalised restricted potential functions.The key feature of this framework allows the system error bound between the state of an uncertain dynamical system and the state of a reference model, which captures a desired closed-loop system performance, to be less than a-priori, user-defined worst-case performance bound, and hence, it has the capability to enforce strict performance guarantees. Examples are provided to demonstrate the efficacy of the proposed set-theoretic model reference adaptive control architecture.

Reduced-order dynamic output feedback control of uncertain discrete-time Markov jump linear systems

NASA Astrophysics Data System (ADS)

Morais, Cecília F.; Braga, Márcio F.; Oliveira, Ricardo C. L. F.; Peres, Pedro L. D.

2017-11-01

This paper deals with the problem of designing reduced-order robust dynamic output feedback controllers for discrete-time Markov jump linear systems (MJLS) with polytopic state space matrices and uncertain transition probabilities. Starting from a full order, mode-dependent and polynomially parameter-dependent dynamic output feedback controller, sufficient linear matrix inequality based conditions are provided for the existence of a robust reduced-order dynamic output feedback stabilising controller with complete, partial or none mode dependency assuring an upper bound to the ? or the ? norm of the closed-loop system. The main advantage of the proposed method when compared to the existing approaches is the fact that the dynamic controllers are exclusively expressed in terms of the decision variables of the problem. In other words, the matrices that define the controller realisation do not depend explicitly on the state space matrices associated with the modes of the MJLS. As a consequence, the method is specially suitable to handle order reduction or cluster availability constraints in the context of ? or ? dynamic output feedback control of discrete-time MJLS. Additionally, as illustrated by means of numerical examples, the proposed approach can provide less conservative results than other conditions in the literature.

Predicting the response of seven Asian glaciers to future climate scenarios using a simple linear glacier model

NASA Astrophysics Data System (ADS)

Ren, Diandong; Karoly, David J.

2008-03-01

Observations from seven Central Asian glaciers (35-55°N; 70-95°E) are used, together with regional temperature data, to infer uncertain parameters for a simple linear model of the glacier length variations. The glacier model is based on first order glacier dynamics and requires the knowledge of reference states of forcing and glacier perturbation magnitude. An adjoint-based variational method is used to optimally determine the glacier reference states in 1900 and the uncertain glacier model parameters. The simple glacier model is then used to estimate the glacier length variations until 2060 using regional temperature projections from an ensemble of climate model simulations for a future climate change scenario (SRES A2). For the period 2000-2060, all glaciers are projected to experience substantial further shrinkage, especially those with gentle slopes (e.g., Glacier Chogo Lungma retreats ˜4 km). Although nearly one-third of the year 2000 length will be reduced for some small glaciers, the existence of the glaciers studied here is not threatened by year 2060. The differences between the individual glacier responses are large. No straightforward relationship is found between glacier size and the projected fractional change of its length.

Memory conformity affects inaccurate memories more than accurate memories.

PubMed

Wright, Daniel B; Villalba, Daniella K

2012-01-01

After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

Citizenship struggles in Soviet successor states.

PubMed

Brubaker, W R

1992-01-01

"The breakup of the Soviet Union has transformed yesterday's internal migrants, secure in their Soviet citizenship, into today's international migrants of contested legitimacy and uncertain membership. This transformation has touched Russians in particular, of whom some 25 million live in non-Russian successor states. This article examines the politics of citizenship vis-a-vis Russian immigrants in the successor states, focusing on the Baltic states, where citizenship has been a matter of sustained and heated controversy." The author concludes that "formal citizenship cannot be divorced from broader questions of substantive belonging. Successor states' willingness to accept Russian immigrants as citizens, and immigrants' readiness to adopt a new state as their state, will depend on the terms of membership for national minorities and the organization of public life in the successor states." Data are from a variety of published sources. excerpt

Proton threshold states in the Na22(p,γ)Mg23 reaction and astrophysical implications

NASA Astrophysics Data System (ADS)

Comisel, H.; Hategan, C.; Graw, G.; Wolter, H. H.

2007-04-01

Proton threshold states in Mg23 are important for the astrophysically relevant proton capture reaction Na22(p,γ)Mg23. In the indirect determination of the resonance strength of the lowest states, which were not accessible by direct methods, some of the spin-parity-assignments remained experimentally uncertain. We have investigated these states with shell model, Coulomb displacement, and Thomas-Ehrman shift calculations. From the comparison of calculated and observed properties, we relate the lowest relevant resonance state at Ex=7643 keV to an excited 3/2+ state in accordance with a recent experimental determination by Jenkins From this we deduce significantly improved values for the Na22(p,γ)Mg23 reaction rate at stellar temperatures below T9=0.1 K.

Historic surface faulting in continental United States and adjacent parts of Mexico

USGS Publications Warehouse

Bonilla, M.G.

1967-01-01

This report summarizes geometric aspects of approximately 35 instances of historic faulting of the ground surface in the continental United States and adjacent parts of Mexico. This information is of immediate importance in the selection and evaluation of sites for vital structures such as nuclear power plants. The data are presented in a table and graphs which show the quantitative relations between various aspects of the faulting. Certain items in the table that are uncertain, poorly known, or not in the published literature are briefly described in the text.

Control of linear uncertain systems utilizing mismatched state observers

NASA Technical Reports Server (NTRS)

Goldstein, B.

1972-01-01

The control of linear continuous dynamical systems is investigated as a problem of limited state feedback control. The equations which describe the structure of an observer are developed constrained to time-invarient systems. The optimal control problem is formulated, accounting for the uncertainty in the design parameters. Expressions for bounds on closed loop stability are also developed. The results indicate that very little uncertainty may be tolerated before divergence occurs in the recursive computation algorithms, and the derived stability bound yields extremely conservative estimates of regions of allowable parameter variations.

Structure of the exotic He 9 nucleus from the no-core shell model with continuum

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

Vorabbi, Matteo; Calci, Angelo; Navratil, Petr

2018-03-13

Here, the exotic 9He nucleus, which presents one of the most extreme neutron-to-proton ratios, belongs to the N = 7 isotonic chain famous for the phenomenon of ground-state parity inversion with decreasing number of protons. Consequently, it would be expected to have an unnatural (positive) parity ground state similar to 11Be and 10Li. Despite many experimental and theoretical investigations, its structure remains uncertain. Apart from the fact that it is unbound, other properties including the spin and parity of its ground state, and the very existence of additional low-lying resonances are still a matter of debate

L1 adaptive control of uncertain gear transmission servo systems with deadzone nonlinearity.

PubMed

Zuo, Zongyu; Li, Xiao; Shi, Zhiguang

2015-09-01

This paper deals with the adaptive control problem of Gear Transmission Servo (GTS) systems in the presence of unknown deadzone nonlinearity and viscous friction. A global differential homeomorphism based on a novel differentiable deadzone model is proposed first. Since there exist both matched and unmatched state-dependent unknown nonlinearities, a full-state feedback L1 adaptive controller is constructed to achieve uniformly bounded transient response in addition to steady-state performance. Finally, simulation results are included to show the elimination of limit cycles, in addition to demonstrating the main results in this paper. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Learning accurate very fast decision trees from uncertain data streams

NASA Astrophysics Data System (ADS)

Liang, Chunquan; Zhang, Yang; Shi, Peng; Hu, Zhengguo

2015-12-01

Most existing works on data stream classification assume the streaming data is precise and definite. Such assumption, however, does not always hold in practice, since data uncertainty is ubiquitous in data stream applications due to imprecise measurement, missing values, privacy protection, etc. The goal of this paper is to learn accurate decision tree models from uncertain data streams for classification analysis. On the basis of very fast decision tree (VFDT) algorithms, we proposed an algorithm for constructing an uncertain VFDT tree with classifiers at tree leaves (uVFDTc). The uVFDTc algorithm can exploit uncertain information effectively and efficiently in both the learning and the classification phases. In the learning phase, it uses Hoeffding bound theory to learn from uncertain data streams and yield fast and reasonable decision trees. In the classification phase, at tree leaves it uses uncertain naive Bayes (UNB) classifiers to improve the classification performance. Experimental results on both synthetic and real-life datasets demonstrate the strong ability of uVFDTc to classify uncertain data streams. The use of UNB at tree leaves has improved the performance of uVFDTc, especially the any-time property, the benefit of exploiting uncertain information, and the robustness against uncertainty.

Implications for the dynamic health of a glacier from comparison of conventional and reference-surface balances

USGS Publications Warehouse

Harrison, W.D.; Cox, L.H.; Hock, R.; March, R.S.; Pettit, E.C.

2009-01-01

Conventional and reference-surface mass-balance data from Gulkana and Wolverine Glaciers, Alaska, USA, are used to address the questions of how rapidly these glaciers are adjusting (or 'responding') to climate, whether their responses are stable, and whether the glaciers are likely to survive in today's climate. Instability means that a glacier will eventually vanish, or at least become greatly reduced in volume, if the climate stabilizes at its present state. A simple non-linear theory of response is presented for the analysis. The response of Gulkana Glacier is characterized by a timescale of several decades, but its stability and therefore its survival in today's climate are uncertain. Wolverine seems to be responding to climate more slowly, on the timescale of one to several centuries. Its stability is also uncertain, but a slower response time would make it more susceptible to climate changes.

H∞ control for uncertain linear system over networks with Bernoulli data dropout and actuator saturation.

PubMed

Yu, Jimin; Yang, Chenchen; Tang, Xiaoming; Wang, Ping

2018-03-01

This paper investigates the H ∞ control problems for uncertain linear system over networks with random communication data dropout and actuator saturation. The random data dropout process is modeled by a Bernoulli distributed white sequence with a known conditional probability distribution and the actuator saturation is confined in a convex hull by introducing a group of auxiliary matrices. By constructing a quadratic Lyapunov function, effective conditions for the state feedback-based H ∞ controller and the observer-based H ∞ controller are proposed in the form of non-convex matrix inequalities to take the random data dropout and actuator saturation into consideration simultaneously, and the problem of non-convex feasibility is solved by applying cone complementarity linearization (CCL) procedure. Finally, two simulation examples are given to demonstrate the effectiveness of the proposed new design techniques. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Uncertainty Quantification in Aeroelasticity

NASA Astrophysics Data System (ADS)

Beran, Philip; Stanford, Bret; Schrock, Christopher

2017-01-01

Physical interactions between a fluid and structure, potentially manifested as self-sustained or divergent oscillations, can be sensitive to many parameters whose values are uncertain. Of interest here are aircraft aeroelastic interactions, which must be accounted for in aircraft certification and design. Deterministic prediction of these aeroelastic behaviors can be difficult owing to physical and computational complexity. New challenges are introduced when physical parameters and elements of the modeling process are uncertain. By viewing aeroelasticity through a nondeterministic prism, where key quantities are assumed stochastic, one may gain insights into how to reduce system uncertainty, increase system robustness, and maintain aeroelastic safety. This article reviews uncertainty quantification in aeroelasticity using traditional analytical techniques not reliant on computational fluid dynamics; compares and contrasts this work with emerging methods based on computational fluid dynamics, which target richer physics; and reviews the state of the art in aeroelastic optimization under uncertainty. Barriers to continued progress, for example, the so-called curse of dimensionality, are discussed.

A novel adaptive switching function on fault tolerable sliding mode control for uncertain stochastic systems.

PubMed

Zahiripour, Seyed Ali; Jalali, Ali Akbar

2014-09-01

A novel switching function based on an optimization strategy for the sliding mode control (SMC) method has been provided for uncertain stochastic systems subject to actuator degradation such that the closed-loop system is globally asymptotically stable with probability one. In the previous researches the focus on sliding surface has been on proportional or proportional-integral function of states. In this research, from a degree of freedom that depends on designer choice is used to meet certain objectives. In the design of the switching function, there is a parameter which the designer can regulate for specified objectives. A sliding-mode controller is synthesized to ensure the reachability of the specified switching surface, despite actuator degradation and uncertainties. Finally, the simulation results demonstrate the effectiveness of the proposed method. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive Output-Feedback Neural Control of Switched Uncertain Nonlinear Systems With Average Dwell Time.

PubMed

Long, Lijun; Zhao, Jun

2015-07-01

This paper investigates the problem of adaptive neural tracking control via output-feedback for a class of switched uncertain nonlinear systems without the measurements of the system states. The unknown control signals are approximated directly by neural networks. A novel adaptive neural control technique for the problem studied is set up by exploiting the average dwell time method and backstepping. A switched filter and different update laws are designed to reduce the conservativeness caused by adoption of a common observer and a common update law for all subsystems. The proposed controllers of subsystems guarantee that all closed-loop signals remain bounded under a class of switching signals with average dwell time, while the output tracking error converges to a small neighborhood of the origin. As an application of the proposed design method, adaptive output feedback neural tracking controllers for a mass-spring-damper system are constructed.

Fuzzy Adaptive Control Design and Discretization for a Class of Nonlinear Uncertain Systems.

PubMed

Zhao, Xudong; Shi, Peng; Zheng, Xiaolong

2016-06-01

In this paper, tracking control problems are investigated for a class of uncertain nonlinear systems in lower triangular form. First, a state-feedback controller is designed by using adaptive backstepping technique and the universal approximation ability of fuzzy logic systems. During the design procedure, a developed method with less computation is proposed by constructing one maximum adaptive parameter. Furthermore, adaptive controllers with nonsymmetric dead-zone are also designed for the systems. Then, a sampled-data control scheme is presented to discretize the obtained continuous-time controller by using the forward Euler method. It is shown that both proposed continuous and discrete controllers can ensure that the system output tracks the target signal with a small bounded error and the other closed-loop signals remain bounded. Two simulation examples are presented to verify the effectiveness and applicability of the proposed new design techniques.

Cluster synchronization transmission of different external signals in discrete uncertain network

NASA Astrophysics Data System (ADS)

Li, Chengren; Lü, Ling; Chen, Liansong; Hong, Yixuan; Zhou, Shuang; Yang, Yiming

2018-07-01

We research cluster synchronization transmissions of different external signals in discrete uncertain network. Based on the Lyapunov theorem, the network controller and the identification law of uncertain adjustment parameter are designed, and they are efficiently used to achieve the cluster synchronization and the identification of uncertain adjustment parameter. In our technical scheme, the network nodes in each cluster and the transmitted external signal can be different, and they allow the presence of uncertain parameters in the network. Especially, we are free to choose the clustering topologies, the cluster number and the node number in each cluster.

A Hierarchical Multi-Model Approach for Uncertainty Segregation, Prioritization and Comparative Evaluation of Competing Modeling Propositions

NASA Astrophysics Data System (ADS)

Tsai, F. T.; Elshall, A. S.; Hanor, J. S.

2012-12-01

Subsurface modeling is challenging because of many possible competing propositions for each uncertain model component. How can we judge that we are selecting the correct proposition for an uncertain model component out of numerous competing propositions? How can we bridge the gap between synthetic mental principles such as mathematical expressions on one hand, and empirical observation such as observation data on the other hand when uncertainty exists on both sides? In this study, we introduce hierarchical Bayesian model averaging (HBMA) as a multi-model (multi-proposition) framework to represent our current state of knowledge and decision for hydrogeological structure modeling. The HBMA framework allows for segregating and prioritizing different sources of uncertainty, and for comparative evaluation of competing propositions for each source of uncertainty. We applied the HBMA to a study of hydrostratigraphy and uncertainty propagation of the Southern Hills aquifer system in the Baton Rouge area, Louisiana. We used geophysical data for hydrogeological structure construction through indictor hydrostratigraphy method and used lithologic data from drillers' logs for model structure calibration. However, due to uncertainty in model data, structure and parameters, multiple possible hydrostratigraphic models were produced and calibrated. The study considered four sources of uncertainties. To evaluate mathematical structure uncertainty, the study considered three different variogram models and two geological stationarity assumptions. With respect to geological structure uncertainty, the study considered two geological structures with respect to the Denham Springs-Scotlandville fault. With respect to data uncertainty, the study considered two calibration data sets. These four sources of uncertainty with their corresponding competing modeling propositions resulted in 24 calibrated models. The results showed that by segregating different sources of uncertainty, HBMA analysis provided insights on uncertainty priorities and propagation. In addition, it assisted in evaluating the relative importance of competing modeling propositions for each uncertain model component. By being able to dissect the uncertain model components and provide weighted representation of the competing propositions for each uncertain model component based on the background knowledge, the HBMA functions as an epistemic framework for advancing knowledge about the system under study.

Civil Military Operations In Ecuador

DTIC Science & Technology

2003-03-01

3455 This process of "re-democratization" meant more than the establishment of simple " electoral democracies඀. The return to democracy meant, for...representation, uncertain electoral outcomes, control of the state by political elected officials, and military subordination to the authority of elected...Abadalá Bucarám won the presidential elections with 54% of the electoral vote. Michael L. Conniff describes the elite reaction to his election

A Portfolio of the Identities of Young People of the South of Russia under the Conditions of Civilizational Choice

ERIC Educational Resources Information Center

Avksent'ev, V. A.; Aksiumov, B. V.

2012-01-01

The problem of civilizational choice is one of the most timely and relevant problems of the entire postcommunist world. Most of the states of the former Soviet Union, including Russia, still find themselves in an uncertain zone of transition. The crisis of civilizational identity, far from being overcome, has even deepened as the Soviet past…

Invasive Species - A Threat to the Homeland?

DTIC Science & Technology

2003-04-07

sharpshooter, an invasive insect that hosts the bacterium Xylella Fastidiosa . The insect was first detected in California in 1990. Although it is...uncertain how it arrived in California, it is believed to have arrived on plants imported from an infected area. The bacterium Xylella Fastidiosa causes...United States may modify the genetics of an invasive species to increase its competitiveness, virulence , lethality, or resistance to control measures

Complex forest dynamics indicate potential for slowing carbon accumulation in the southeastern United States

Treesearch

John W. Coulston; David N. Wear; James M. Vose

2015-01-01

Over the past century forest regrowth in Europe and North America expanded forest carbon (C) sinks and offset C emissions but future C accumulation is uncertain. Policy makers need insights into forest C dynamics as they anticipate emissions futures and goals. We used land use and forest inventory data to estimate how forest C dynamics have changed in the southeastern...

Allocating conservation resources between areas where persistence of a species is uncertain.

PubMed

McDonald-Madden, Eve; Chadès, Iadine; McCarthy, Michael A; Linkie, Matthew; Possingham, Hugh P

2011-04-01

Research on the allocation of resources to manage threatened species typically assumes that the state of the system is completely observable; for example whether a species is present or not. The majority of this research has converged on modeling problems as Markov decision processes (MDP), which give an optimal strategy driven by the current state of the system being managed. However, the presence of threatened species in an area can be uncertain. Typically, resource allocation among multiple conservation areas has been based on the biggest expected benefit (return on investment) but fails to incorporate the risk of imperfect detection. We provide the first decision-making framework for confronting the trade-off between information and return on investment, and we illustrate the approach for populations of the Sumatran tiger (Panthera tigris sumatrae) in Kerinci Seblat National Park. The problem is posed as a partially observable Markov decision process (POMDP), which extends MDP to incorporate incomplete detection and allows decisions based on our confidence in particular states. POMDP has previously been used for making optimal management decisions for a single population of a threatened species. We extend this work by investigating two populations, enabling us to explore the importance of variation in expected return on investment between populations on how we should act. We compare the performance of optimal strategies derived assuming complete (MDP) and incomplete (POMDP) observability. We find that uncertainty about the presence of a species affects how we should act. Further, we show that assuming full knowledge of a species presence will deliver poorer strategic outcomes than if uncertainty about a species status is explicitly considered. MDP solutions perform up to 90% worse than the POMDP for highly cryptic species, and they only converge in performance when we are certain of observing the species during management: an unlikely scenario for many threatened species. This study illustrates an approach to allocating limited resources to threatened species where the conservation status of the species in different areas is uncertain. The results highlight the importance of including partial observability in future models of optimal species management when the species of concern is cryptic in nature.

Development of Gridded Ensemble Precipitation and Temperature Datasets for the Contiguous United States Plus Hawai'i and Alaska

NASA Astrophysics Data System (ADS)

Newman, A. J.; Clark, M. P.; Nijssen, B.; Wood, A.; Gutmann, E. D.; Mizukami, N.; Longman, R. J.; Giambelluca, T. W.; Cherry, J.; Nowak, K.; Arnold, J.; Prein, A. F.

2016-12-01

Gridded precipitation and temperature products are inherently uncertain due to myriad factors. These include interpolation from a sparse observation network, measurement representativeness, and measurement errors. Despite this inherent uncertainty, uncertainty is typically not included, or is a specific addition to each dataset without much general applicability across different datasets. A lack of quantitative uncertainty estimates for hydrometeorological forcing fields limits their utility to support land surface and hydrologic modeling techniques such as data assimilation, probabilistic forecasting and verification. To address this gap, we have developed a first of its kind gridded, observation-based ensemble of precipitation and temperature at a daily increment for the period 1980-2012 over the United States (including Alaska and Hawaii). A longer, higher resolution version (1970-present, 1/16th degree) has also been implemented to support real-time hydrologic- monitoring and prediction in several regional US domains. We will present the development and evaluation of the dataset, along with initial applications of the dataset for ensemble data assimilation and probabilistic evaluation of high resolution regional climate model simulations. We will also present results on the new high resolution products for Alaska and Hawaii (2 km and 250 m respectively), to complete the first ensemble observation based product suite for the entire 50 states. Finally, we will present plans to improve the ensemble dataset, focusing on efforts to improve the methods used for station interpolation and ensemble generation, as well as methods to fuse station data with numerical weather prediction model output.

Characterizing traffic under uncertain disruptions : an experimental approach.

DOT National Transportation Integrated Search

2013-03-01

The objective of the research is to study long-term traffic patterns under uncertain disruptions using : data collected from human subjects who simultaneously make route choices in controlled PC-based : laboratory experiments. Uncertain disruptions t...

Econometric models for predicting confusion crop ratios

NASA Technical Reports Server (NTRS)

Umberger, D. E.; Proctor, M. H.; Clark, J. E.; Eisgruber, L. M.; Braschler, C. B. (Principal Investigator)

1979-01-01

Results for both the United States and Canada show that econometric models can provide estimates of confusion crop ratios that are more accurate than historical ratios. Whether these models can support the LACIE 90/90 accuracy criterion is uncertain. In the United States, experimenting with additional model formulations could provide improved methods models in some CRD's, particularly in winter wheat. Improved models may also be possible for the Canadian CD's. The more aggressive province/state models outperformed individual CD/CRD models. This result was expected partly because acreage statistics are based on sampling procedures, and the sampling precision declines from the province/state to the CD/CRD level. Declining sampling precision and the need to substitute province/state data for the CD/CRD data introduced measurement error into the CD/CRD models.

Planetesimal Formation through the Streaming Instability

NASA Astrophysics Data System (ADS)

Yang, Chao-Chin; Johansen, Anders; Schäfer, Urs

2015-12-01

The streaming instability is a promising mechanism to circumvent the barriers in direct dust growth and lead to the formation of planetesimals, as demonstrated by many previous studies. In order to resolve the thin layer of solids, however, most of these studies were focused on a local region of a protoplanetary disk with a limited simulation domain. It remains uncertain how the streaming instability is affected by the disk gas on large scales, and models that have sufficient dynamical range to capture both the thin particle layer and the large-scale disk dynamics are required.We hereby systematically push the limits of the computational domain up to more than the gas scale height, and study the particle-gas interaction on large scales in the saturated state of the streaming instability and the initial mass function of the resulting planetesimals. To overcome the numerical challenges posed by this kind of models, we have developed a new technique to simultaneously relieve the stringent time step constraints due to small-sized particles and strong local solid concentrations. Using these models, we demonstrate that the streaming instability can drive multiple radial, filamentary concentrations of solids, implying that planetesimals are born in well separated belt-like structures. We also find that the initial mass function of planetesimals via the streaming instability has a characteristic exponential form, which is robust against computational domain as well as resolution. These findings will help us further constrain the cosmochemical history of the Solar system as well as the planet formation theory in general.

[An examination of "Minamata disease general investigation and research liaison council"--The process of making uncertain the organic mercury causal theory].

PubMed

Nakano, Hiroshi

2010-01-01

Minamata disease occurred because inhabitants consumed the polluted seafood. The official confirmation of Minamata disease was in 1956. However, the material cause of that disease was uncertain at that time. The Minamata Food Poisoning Sub-committee, under authority of the Food Hygiene Investigation Committee of the Ministry of Health and Welfare, determined the material cause of Minamata disease to be a certain kind of organic mercury in 1959. The sub-committee was dissolved after their report. The discussion about the investigation of the cause was performed in a conference initiated by the Economic Planning Agency, which was titled "Minamata Disease General Investigation and Research Liaison Council". The Participants were eight scientists; four fishery scientists, two chemists, and only two medical scientists, which implied that only examination of the organic mercury was to be discussion. The conference was held four times from 1960 to 1961. In the first and second conferences, the organic mercury research from a medical perspective progressed in cooperation with fishery sciences. In the third conference, it was reported that UCHIDA Makio, professor of Kumamoto University, had found organic mercury crystal in the shellfish found in Minamata-bay. Authorities of biochemistry and medicine in the third conference criticized UCHIDA's research. At the fourth conference, reports contradicting his research were presented. Although those anti-UCHIDA reports were not verified, AKAHORI Shiro, the highest authority of biochemistry, not only accepted them, but also expressed doubt in the organic mercury causal theory. Therefore, this theory was recognized as uncertain.

Minimizing the regrets of long-term urban floodplain management decisions under deeply uncertain climate change

NASA Astrophysics Data System (ADS)

Hecht, J. S.; Kirshen, P. H.; Vogel, R. M.

2016-12-01

Making long-term floodplain management decisions under uncertain climate change is a major urban planning challenge of the 21stcentury. To support these efforts, we introduce a screening-level optimization model that identifies adaptation portfolios by minimizing the regrets associated with their flood-control and damage costs under different climate change trajectories that are deeply uncertain, i.e. have probabilities that cannot be specified plausibly. This mixed integer program explicitly considers the coupled damage-reduction impacts of different floodwall designs and property-scale investments (first-floor elevation, wet floodproofing of basements, permanent retreat and insurance), recommends implementation schedules, and assesses impacts to stakeholders residing in three types of homes. An application to a stylized municipality illuminates many nonlinear system dynamics stemming from large fixed capital costs, infrastructure design thresholds, and discharge-depth-damage relationships. If stakeholders tolerate mild damage, floodwalls that fully protect a community from large design events are less cost-effective than portfolios featuring both smaller floodwalls and property-scale measures. Potential losses of property tax revenue from permanent retreat motivate municipal property-tax initiatives for adaptation financing. Yet, insurance incentives for first-floor elevation may discourage locally financed floodwalls, in turn making lower-income residents more vulnerable to severe flooding. A budget constraint analysis underscores the benefits of flexible floodwall designs with low incremental expansion costs while near-optimal solutions demonstrate the scheduling flexibility of many property-scale measures. Finally, an equity analysis shows the importance of evaluating the overpayment and under-design regrets of recommended adaptation portfolios for each stakeholder and contrasts them to single-scenario model results.

A novel medical information management and decision model for uncertain demand optimization.

PubMed

Bi, Ya

2015-01-01

Accurately planning the procurement volume is an effective measure for controlling the medicine inventory cost. Due to uncertain demand it is difficult to make accurate decision on procurement volume. As to the biomedicine sensitive to time and season demand, the uncertain demand fitted by the fuzzy mathematics method is obviously better than general random distribution functions. To establish a novel medical information management and decision model for uncertain demand optimization. A novel optimal management and decision model under uncertain demand has been presented based on fuzzy mathematics and a new comprehensive improved particle swarm algorithm. The optimal management and decision model can effectively reduce the medicine inventory cost. The proposed improved particle swarm optimization is a simple and effective algorithm to improve the Fuzzy interference and hence effectively reduce the calculation complexity of the optimal management and decision model. Therefore the new model can be used for accurate decision on procurement volume under uncertain demand.

Some properties of the filamentary nebula at 1723 - 46

NASA Technical Reports Server (NTRS)

Bedford, D. K.; Elliott, K. H.; Ramsey, B.; Meaburn, J.

1984-01-01

High resolution spectra of the interstellar NaI D2 absorption line have been obtained for seven B-type stars aligned with an extensive filamentary nebula. Very fine filaments have now been found on a high contrast print of a deep H-alpha and forbidden N II plate, making identification as a fossilized remnant probable but uncertain. The inferred age is about 20,000 yr, the distance less than 200 pc, the diameter less than 17.5 pec, but the initial energy is only about 2 x 10 to the 47th erg.

Embryonic Mutant Huntingtin Aggregate Formation in Mouse Models of Huntington's Disease.

PubMed

Osmand, Alexander P; Bichell, Terry Jo; Bowman, Aaron B; Bates, Gillian P

2016-12-15

The role of aggregate formation in the pathophysiology of Huntington's disease (HD) remains uncertain. However, the temporal appearance of aggregates tends to correlate with the onset of symptoms and the numbers of neuropil aggregates correlate with the progression of clinical disease. Using highly sensitive immunohistochemical methods we have detected the appearance of diffuse aggregates during embryonic development in the R6/2 and YAC128 mouse models of HD. These are initially seen in developing axonal tracts and appear to spread throughout the cerebrum in the early neonate.

Price-cap Regulation, Uncertainty and the Price Evolution of New Pharmaceuticals.

PubMed

Shajarizadeh, Ali; Hollis, Aidan

2015-08-01

This paper examines the effect of the regulations restricting price increases on the evolution of pharmaceutical prices. A novel theoretical model shows that this policy leads firms to price new drugs with uncertain demand above the expected value initially. Price decreases after drug launch are more likely, the higher the uncertainty. We empirically test the model's predictions using data from the Canadian pharmaceutical market. The level of uncertainty is shown to play a crucial role in drug pricing strategies. © 2014 The Authors. Health Economics Published by John Wiley & Sons Ltd.

A self-agency bias in preschoolers' causal inferences

PubMed Central

Kushnir, Tamar; Wellman, Henry M.; Gelman, Susan A.

2013-01-01

Preschoolers' causal learning from intentional actions – causal interventions – is subject to a self-agency bias. We propose that this bias is evidence-based; it is responsive to causal uncertainty. In the current studies, two causes (one child-controlled, one experimenter-controlled) were associated with one or two effects, first independently, then simultaneously. When initial independent effects were probabilistic, and thus subsequent simultaneous actions were causally ambiguous, children showed a self-agency bias. Children showed no bias when initial effects were deterministic. Further controls establish that children's self-agency bias is not a wholesale preference but rather is influenced by uncertainty in causal evidence. These results demonstrate that children's own experience of action influences their causal learning, and suggest possible benefits in uncertain and ambiguous everyday learning contexts. PMID:19271843

Effect of chemical kinetics uncertainties on calculated constituents in a tropospheric photochemical model

NASA Technical Reports Server (NTRS)

Thompson, Anne M.; Stewart, Richard W.

1991-01-01

Random photochemical reaction rates are employed in a 1D photochemical model to examine uncertainties in tropospheric concentrations and thereby determine critical kinetic processes and significant correlations. Monte Carlo computations are used to simulate different chemical environments and their related imprecisions. The most critical processes are the primary photodissociation of O3 (which initiates ozone destruction) and NO2 (which initiates ozone formation), and the OH/methane reaction is significant. Several correlations and anticorrelations between species are discussed, and the ozone/transient OH correlation is examined in detail. One important result of the modeling is that estimates of global OH are generally about 25 percent uncertain, limiting the precision of photochemical models. Techniques for reducing the imprecision are discussed which emphasize the use of species and radical species measurements.

Altered subjective reward valuation among female heavy marijuana users.

PubMed

Hefner, Kathryn R; Starr, Mark J

2017-02-01

Maladaptive decision-making is a cardinal feature of drug use, contributing to ongoing use, and reflecting alterations in how drug users assess uncertain reward value. Accumulating evidence indicates the consequences of heavy marijuana use are worse for female versus male animals and humans, but research assessing sex differences in reward-related decision-making among marijuana users remains scarce. We examined sex differences in the subjective valuation of certain and uncertain rewards among heavy marijuana users (52; 26 male and 26 female) and controls (52; 26 male and 26 female). We offered male and female heavy marijuana users and controls monetary rewards of certain and uncertain (probabilistic) values. We measured how preferences for uncertain rewards varied by the objective value of those rewards, moderators of reward uncertainty, Marijuana Group and Sex. Men were more sensitive to changes in the objective value of uncertain rewards than women. However, this effect of Sex differed by Marijuana Group. Female heavy marijuana users were more sensitive to changes in uncertain reward value, particularly when the "stakes" were high (i.e., greater difference between potential uncertain rewards), than female controls. Female heavy marijuana users' sensitivity to changes in the value of high stakes uncertain rewards was comparable to male marijuana users and controls. In contrast, male marijuana users' sensitivity to changes in the value of high stakes uncertain rewards did not differ from male controls. These results suggest sex differences in sensitivity to high risk rewards may be one pathway contributing to severer consequences of heavy marijuana use among women. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Altered subjective reward valuation among female heavy marijuana users

PubMed Central

Hefner, Kathryn R.; Starr, Mark. J.

2016-01-01

Maladaptive decision-making is a cardinal feature of drug use, contributing to ongoing use, and reflecting alterations in how drug users assess uncertain reward value. Accumulating evidence indicates the consequences of heavy marijuana use are worse for female versus male animals and humans, but research assessing sex differences in reward-related decision-making among marijuana users remains scarce. We examined sex differences in the subjective valuation of certain and uncertain rewards among heavy marijuana users (52; 26 male and 26 female) and controls (52; 26 male and 26 female). We offered male and female heavy marijuana users and controls monetary rewards of certain and uncertain (probabilistic) values. We measured how preferences for uncertain rewards varied by the objective value of those rewards, moderators of reward uncertainty, marijuana use, and sex. Men were more sensitive to changes in the objective value of uncertain rewards than women. However, this effect of sex differed by marijuana group. Female heavy marijuana users were more sensitive to changes in uncertain reward value, particularly when the ‘stakes’ were high (i.e., greater difference between potential uncertain rewards), than female controls. Female heavy marijuana users’ sensitivity to changes in the value of high stakes uncertain rewards was comparable to male marijuana users and controls. In contrast, male marijuana users’ sensitivity to changes in the value of high stakes uncertain rewards did not differ from male controls. These results suggest sex differences in sensitivity to high risk rewards may be one pathway contributing to severer consequences of heavy marijuana use among women. PMID:27936816

The Absolute Stability Analysis in Fuzzy Control Systems with Parametric Uncertainties and Reference Inputs

NASA Astrophysics Data System (ADS)

Wu, Bing-Fei; Ma, Li-Shan; Perng, Jau-Woei

This study analyzes the absolute stability in P and PD type fuzzy logic control systems with both certain and uncertain linear plants. Stability analysis includes the reference input, actuator gain and interval plant parameters. For certain linear plants, the stability (i.e. the stable equilibriums of error) in P and PD types is analyzed with the Popov or linearization methods under various reference inputs and actuator gains. The steady state errors of fuzzy control systems are also addressed in the parameter plane. The parametric robust Popov criterion for parametric absolute stability based on Lur'e systems is also applied to the stability analysis of P type fuzzy control systems with uncertain plants. The PD type fuzzy logic controller in our approach is a single-input fuzzy logic controller and is transformed into the P type for analysis. In our work, the absolute stability analysis of fuzzy control systems is given with respect to a non-zero reference input and an uncertain linear plant with the parametric robust Popov criterion unlike previous works. Moreover, a fuzzy current controlled RC circuit is designed with PSPICE models. Both numerical and PSPICE simulations are provided to verify the analytical results. Furthermore, the oscillation mechanism in fuzzy control systems is specified with various equilibrium points of view in the simulation example. Finally, the comparisons are also given to show the effectiveness of the analysis method.

Impact of Data Assimilation on Cost-Accuracy Tradeoff in Multi-Fidelity Models at the Example of an Infiltration Problem

NASA Astrophysics Data System (ADS)

Sinsbeck, Michael; Tartakovsky, Daniel

2015-04-01

Infiltration into top soil can be described by alternative models with different degrees of fidelity: Richards equation and the Green-Ampt model. These models typically contain uncertain parameters and forcings, rendering predictions of the state variables uncertain as well. Within the probabilistic framework, solutions of these models are given in terms of their probability density functions (PDFs) that, in the presence of data, can be treated as prior distributions. The assimilation of soil moisture data into model predictions, e.g., via a Bayesian updating of solution PDFs, poses a question of model selection: Given a significant difference in computational cost, is a lower-fidelity model preferable to its higher-fidelity counter-part? We investigate this question in the context of heterogeneous porous media, whose hydraulic properties are uncertain. While low-fidelity (reduced-complexity) models introduce a model error, their moderate computational cost makes it possible to generate more realizations, which reduces the (e.g., Monte Carlo) sampling or stochastic error. The ratio between these two errors determines the model with the smallest total error. We found assimilation of measurements of a quantity of interest (the soil moisture content, in our example) to decrease the model error, increasing the probability that the predictive accuracy of a reduced-complexity model does not fall below that of its higher-fidelity counterpart.

A new adaptive estimation method of spacecraft thermal mathematical model with an ensemble Kalman filter

NASA Astrophysics Data System (ADS)

Akita, T.; Takaki, R.; Shima, E.

2012-04-01

An adaptive estimation method of spacecraft thermal mathematical model is presented. The method is based on the ensemble Kalman filter, which can effectively handle the nonlinearities contained in the thermal model. The state space equations of the thermal mathematical model is derived, where both temperature and uncertain thermal characteristic parameters are considered as the state variables. In the method, the thermal characteristic parameters are automatically estimated as the outputs of the filtered state variables, whereas, in the usual thermal model correlation, they are manually identified by experienced engineers using trial-and-error approach. A numerical experiment of a simple small satellite is provided to verify the effectiveness of the presented method.

DDT acceleration of mammary gland tumors induced in the male Sprague-Dawley rat by 2-acetamidophenanthrene.

PubMed

Scribner, J D; Mottet, N K

1981-01-01

2-Acetamidophenanthrene (AAP) yields adducts to rat liver DNA and RNA in amounts comparable to those found for the potent hepatocarcinogen 2-acetamidofluorene, but is not hepatocarcinogenic. This suggested that AAP might initiate liver tumors, but was incapable of causing their progression to a detectable state. To test this hypothesis, the protocol devised by Peraino was used, in which 21-day-old male Sprague-Dawley rats were fed 0.02% AAP in a grain diet for three weeks. this was followed by long-term feeding of 0.05% 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT). The mean latent period of all tumors (primarily mammary tumors) was reduced about six months by the DDT feeding. No tumors were found in rats treated with DDT only. Livers in all animals appeared normal at autopsy or on laparotomy, and showed barely detectable signs of toxicity upon histological examination. Thus, we have found that a once wide-spread environmental chemical acts as a tumor accelerator on a major target for human tumors. Because this finding is in the male rat, the significance of this result for breast cancer in women is uncertain.

Missing great earthquakes

USGS Publications Warehouse

Hough, Susan E.

2013-01-01

The occurrence of three earthquakes with moment magnitude (Mw) greater than 8.8 and six earthquakes larger than Mw 8.5, since 2004, has raised interest in the long-term global rate of great earthquakes. Past studies have focused on the analysis of earthquakes since 1900, which roughly marks the start of the instrumental era in seismology. Before this time, the catalog is less complete and magnitude estimates are more uncertain. Yet substantial information is available for earthquakes before 1900, and the catalog of historical events is being used increasingly to improve hazard assessment. Here I consider the catalog of historical earthquakes and show that approximately half of all Mw ≥ 8.5 earthquakes are likely missing or underestimated in the 19th century. I further present a reconsideration of the felt effects of the 8 February 1843, Lesser Antilles earthquake, including a first thorough assessment of felt reports from the United States, and show it is an example of a known historical earthquake that was significantly larger than initially estimated. The results suggest that incorporation of best available catalogs of historical earthquakes will likely lead to a significant underestimation of seismic hazard and/or the maximum possible magnitude in many regions, including parts of the Caribbean.

Orbiting space debris: Dangers, measurement, and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-01-01

Space debris is a growing environmental problem. Accumulation of objects in Earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, Unites States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-Earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical, and diplomatic components. Actions need to be taken now for the following reasons: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the the loss of critical space systems such as the Space Shuttle or the Space Station.

Neural basis of uncertain cue processing in trait anxiety.

PubMed

Zhang, Meng; Ma, Chao; Luo, Yanyan; Li, Ji; Li, Qingwei; Liu, Yijun; Ding, Cody; Qiu, Jiang

2016-02-19

Individuals with high trait anxiety form a non-clinical group with a predisposition for an anxiety-related bias in emotional and cognitive processing that is considered by some to be a prerequisite for psychiatric disorders. Anxious individuals tend to experience more worry under uncertainty, and processing uncertain information is an important, but often overlooked factor in anxiety. So, we decided to explore the brain correlates of processing uncertain information in individuals with high trait anxiety using the learn-test paradigm. Behaviorally, the percentages on memory test and the likelihood ratios of identifying novel stimuli under uncertainty were similar to the certain fear condition, but different from the certain neutral condition. The brain results showed that the visual cortex, bilateral fusiform gyrus, and right parahippocampal gyrus were active during the processing of uncertain cues. Moreover, we found that trait anxiety was positively correlated with the BOLD signal of the right parahippocampal gyrus during the processing of uncertain cues. No significant results were found in the amygdala during uncertain cue processing. These results suggest that memory retrieval is associated with uncertain cue processing, which is underpinned by over-activation of the right parahippocampal gyrus, in individuals with high trait anxiety.

Adaptive route choice modeling in uncertain traffic networks with real-time information.

DOT National Transportation Integrated Search

2013-03-01

The objective of the research is to study travelers' route choice behavior in uncertain traffic networks : with real-time information. The research is motivated by two observations of the traffic system: 1) : the system is inherently uncertain with r...

Technology Proliferation: Acquisition Strategies and Opportunities for an Uncertain Future

DTIC Science & Technology

2018-04-20

The large programs of record characteristic of federal acquisition consist of rigorous research, development, testing, and evaluation (RDT&E...and evaluation (IOT&E) activities drive the program toward the decision to enter full rate production (FRP). Finally, in the sustainment phase, the...the new feature by a full release at a later date, or halt the development altogether. As stated by the Director of Operational Test and Evaluation

Mexican Civil-Military Relations: Stability and Strength in an Uncertain Environment

DTIC Science & Technology

2011-10-28

colonial rule ended in 1821, Mexico was an unstable yet independent state until General Porfirio Diaz established a dictatorship in 1876, running the...ruthlessness that he ruled for 34 years. The Mexican people needed stability, and Diaz’ approach to governance offered economic reforms...Factbook (Washington: CSIS Americas Program, 1999), 3. transformed the ruling party’s structure6 by establishing four “corporate sectors” within

U.S. and South Korean Cooperation in the World Nuclear Energy Market: Major Policy Considerations

DTIC Science & Technology

2010-01-21

a laboratory-scale research program on reprocessing spent fuel with an advanced pyroprocessing technique. However, the level of consensus over the... pyroprocessing option among government agencies, Korean electric utilities, and the public remains uncertain. The current U.S.-Korea 123 agreement...permission. KAERI’s pyroprocessing technology would partially separate plutonium and uranium from spent fuel, but the United States has not allowed the

Potential Impacts of Climate Change in the United States

DTIC Science & Technology

2009-05-01

could experience what are now considered 100-year floods every three to four years by the end of the 21st century.75 Ocean Acidification . The world’s...could be particularly harmful.81 In addition, shellfish, plankton, and corals face a highly uncertain threat from acidification of the world’s...eds., Climate Change 2007: Impacts, Adaptation and Vulnerability, p. 213; Raven and others, Ocean Acidification Due to Increasing Atmospheric

Generalized Distributed Consensus-based Algorithms for Uncertain Systems and Networks

DTIC Science & Technology

2010-01-01

time linear systems with markovian jumping parameters and additive disturbances. SIAM Journal on Control and Optimization, 44(4):1165– 1191, 2005... time marko- vian jump linear systems , in the presence of delayed mode observations. Proceed- ings of the 2008 IEEE American Control Conference, pages...Markovian Jump Linear System state estimation . . . . 147 6 Conclusions 152 A Discrete- Time Coupled Matrix Equations 156 A.1 Properties of a special

Extensions of output variance constrained controllers to hard constraints

NASA Technical Reports Server (NTRS)

Skelton, R.; Zhu, G.

1989-01-01

Covariance Controllers assign specified matrix values to the state covariance. A number of robustness results are directly related to the covariance matrix. The conservatism in known upperbounds on the H infinity, L infinity, and L (sub 2) norms for stability and disturbance robustness of linear uncertain systems using covariance controllers is illustrated with examples. These results are illustrated for continuous and discrete time systems. **** ONLY 2 BLOCK MARKERS FOUND -- RETRY *****

Probability-based hazard avoidance guidance for planetary landing

NASA Astrophysics Data System (ADS)

Yuan, Xu; Yu, Zhengshi; Cui, Pingyuan; Xu, Rui; Zhu, Shengying; Cao, Menglong; Luan, Enjie

2018-03-01

Future landing and sample return missions on planets and small bodies will seek landing sites with high scientific value, which may be located in hazardous terrains. Autonomous landing in such hazardous terrains and highly uncertain planetary environments is particularly challenging. Onboard hazard avoidance ability is indispensable, and the algorithms must be robust to uncertainties. In this paper, a novel probability-based hazard avoidance guidance method is developed for landing in hazardous terrains on planets or small bodies. By regarding the lander state as probabilistic, the proposed guidance algorithm exploits information on the uncertainty of lander position and calculates the probability of collision with each hazard. The collision probability serves as an accurate safety index, which quantifies the impact of uncertainties on the lander safety. Based on the collision probability evaluation, the state uncertainty of the lander is explicitly taken into account in the derivation of the hazard avoidance guidance law, which contributes to enhancing the robustness to the uncertain dynamics of planetary landing. The proposed probability-based method derives fully analytic expressions and does not require off-line trajectory generation. Therefore, it is appropriate for real-time implementation. The performance of the probability-based guidance law is investigated via a set of simulations, and the effectiveness and robustness under uncertainties are demonstrated.

Error tracking control for underactuated overhead cranes against arbitrary initial payload swing angles

NASA Astrophysics Data System (ADS)

Zhang, Menghua; Ma, Xin; Rong, Xuewen; Tian, Xincheng; Li, Yibin

2017-02-01

This paper exploits an error tracking control method for overhead crane systems for which the error trajectories for the trolley and the payload swing can be pre-specified. The proposed method does not require that the initial payload swing angle remains zero, whereas this requirement is usually assumed in conventional methods. The significant feature of the proposed method is its superior control performance as well as its strong robustness over different or uncertain rope lengths, payload masses, desired positions, initial payload swing angles, and external disturbances. Owing to the same attenuation behavior, the desired error trajectory for the trolley for each traveling distance is not needed to be reset, which is easy to implement in practical applications. By converting the error tracking overhead crane dynamics to the objective system, we obtain the error tracking control law for arbitrary initial payload swing angles. Lyapunov techniques and LaSalle's invariance theorem are utilized to prove the convergence and stability of the closed-loop system. Simulation and experimental results are illustrated to validate the superior performance of the proposed error tracking control method.

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance American College of Chest Physicians.

PubMed

Douglas, Pamela S; Garcia, Mario J; Haines, David E; Lai, Wyman W; Manning, Warren J; Patel, Ayan R; Picard, Michael H; Polk, Donna M; Ragosta, Michael; Parker Ward, R; Weiner, Rory B

2011-03-01

The American College of Cardiology Foundation (ACCF), in partnership with the American Society of Echocardiography (ASE) and along with key specialty and subspecialty societies, conducted a review of common clinical scenarios where echocardiography is frequently considered. This document combines and updates the original transthoracic and transesophageal echocardiography appropriateness criteria published in 2007 (1) and the original stress echocardiography appropriateness criteria published in 2008 (2). This revision reflects new clinical data, reflects changes in test utilization patterns,and clarifies echocardiography use where omissions or lack of clarity existed in the original criteria.The indications (clinical scenarios)were derived from common applications or anticipated uses, as well as from current clinical practice guidelines and results of studies examining the implementation of the original appropriate use criteria (AUC).The 202 indications in this document were developed by a diverse writing group and scored by a separate independent technical panel on a scale of 1 to 9,to designate appropriate use(median 7 to 9), uncertain use(median 4 to 6), and inappropriate use (median 1 to 3). Ninety-seven indications were rated as appropriate, 34 were rated as uncertain, and 71 were rated as inappropriate. In general,the use of echocardiography for initial diagnosis when there is a change in clinical status or when the results of the echocardiogram are anticipated to change patient management were rated appropriate. Routine testing when there was no change in clinical status or when results of testing were unlikely to modify management were more likely to be inappropriate than appropriate/uncertain.The AUC for echocardiography have the potential to impact physician decision making,healthcare delivery, and reimbursement policy. Furthermore,recognition of uncertain clinical scenarios facilitates identification of areas that would benefit from future research.

Diversified models for portfolio selection based on uncertain semivariance

NASA Astrophysics Data System (ADS)

Chen, Lin; Peng, Jin; Zhang, Bo; Rosyida, Isnaini

2017-02-01

Since the financial markets are complex, sometimes the future security returns are represented mainly based on experts' estimations due to lack of historical data. This paper proposes a semivariance method for diversified portfolio selection, in which the security returns are given subjective to experts' estimations and depicted as uncertain variables. In the paper, three properties of the semivariance of uncertain variables are verified. Based on the concept of semivariance of uncertain variables, two types of mean-semivariance diversified models for uncertain portfolio selection are proposed. Since the models are complex, a hybrid intelligent algorithm which is based on 99-method and genetic algorithm is designed to solve the models. In this hybrid intelligent algorithm, 99-method is applied to compute the expected value and semivariance of uncertain variables, and genetic algorithm is employed to seek the best allocation plan for portfolio selection. At last, several numerical examples are presented to illustrate the modelling idea and the effectiveness of the algorithm.

The treatment of mixing in core helium-burning models - III. Suppressing core breathing pulses with a new constraint on overshoot

NASA Astrophysics Data System (ADS)

Constantino, Thomas; Campbell, Simon W.; Lattanzio, John C.

2017-12-01

Theoretical predictions for the core helium burning phase of stellar evolution are highly sensitive to the uncertain treatment of mixing at convective boundaries. In the last few years, interest in constraining the uncertain structure of their deep interiors has been renewed by insights from asteroseismology. Recently, Spruit proposed a limit for the rate of growth of helium-burning convective cores based on the higher buoyancy of material ingested from outside the convective core. In this paper we test the implications of such a limit for stellar models with a range of initial mass and metallicity. We find that the constraint on mixing beyond the Schwarzschild boundary has a significant effect on the evolution late in core helium burning, when core breathing pulses occur and the ingestion rate of helium is fastest. Ordinarily, core breathing pulses prolong the core helium burning lifetime to such an extent that models are at odds with observations of globular cluster populations. Across a wide range of initial stellar masses (0.83 ≤ M/M⊙ ≤ 5), applying the Spruit constraint reduces the core helium burning lifetime because core breathing pulses are either avoided or their number and severity reduced. The constraint suggested by Spruit therefore helps to resolve significant discrepancies between observations and theoretical predictions. Specifically, we find improved agreement for R2 (the observed ratio of asymptotic giant branch to horizontal branch stars in globular clusters), the luminosity difference between these two groups, and in asteroseismology, the mixed-mode period spacing detected in red clump stars in the Kepler field.

Public Response to a Near-Miss Nuclear Accident Scenario Varying in Causal Attributions and Outcome Uncertainty.

PubMed

Cui, Jinshu; Rosoff, Heather; John, Richard S

2018-05-01

Many studies have investigated public reactions to nuclear accidents. However, few studies focused on more common events when a serious accident could have happened but did not. This study evaluated public response (emotional, cognitive, and behavioral) over three phases of a near-miss nuclear accident. Simulating a loss-of-coolant accident (LOCA) scenario, we manipulated (1) attribution for the initial cause of the incident (software failure vs. cyber terrorist attack vs. earthquake), (2) attribution for halting the incident (fail-safe system design vs. an intervention by an individual expert vs. a chance coincidence), and (3) level of uncertainty (certain vs. uncertain) about risk of a future radiation leak after the LOCA is halted. A total of 773 respondents were sampled using a 3 × 3 × 2 between-subjects design. Results from both MANCOVA and structural equation modeling (SEM) indicate that respondents experienced more negative affect, perceived more risk, and expressed more avoidance behavioral intention when the near-miss event was initiated by an external attributed source (e.g., earthquake) compared to an internally attributed source (e.g., software failure). Similarly, respondents also indicated greater negative affect, perceived risk, and avoidance behavioral intentions when the future impact of the near-miss incident on people and the environment remained uncertain. Results from SEM analyses also suggested that negative affect predicted risk perception, and both predicted avoidance behavior. Affect, risk perception, and avoidance behavior demonstrated high stability (i.e., reliability) from one phase to the next. © 2017 Society for Risk Analysis.

The Clinical Significance of Occult Gastrointestinal Primary Tumours in Metastatic Cancer: A Population Retrospective Cohort Study.

PubMed

Hannouf, Malek B; Winquist, Eric; Mahmud, Salaheddin M; Brackstone, Muriel; Sarma, Sisira; Rodrigues, George; Rogan, Peter K; Hoch, Jeffrey S; Zaric, Gregory S

2018-01-01

The purpose of this study was to estimate the incidence of occult gastrointestinal (GI) primary tumours in patients with metastatic cancer of uncertain primary origin and evaluate their influence on treatments and overall survival (OS). We used population heath data from Manitoba, Canada to identify all patients initially diagnosed with metastatic cancer between 2002 and 2011. We defined patients to have "occult" primary tumour if the primary was found at least 6 months after initial diagnosis. Otherwise, we considered primary tumours as "obvious." We used propensity-score methods to match each patient with occult GI tumour to four patients with obvious GI tumour on all known clinicopathologic features. We compared treatments and 2-year survival data between the two patient groups and assessed treatment effect on OS using Cox regression adjustment. Eighty-three patients had occult GI primary tumours, accounting for 17.6% of men and 14% of women with metastatic cancer of uncertain primary. A 1:4 matching created a matched group of 332 patients with obvious GI primary tumour. Occult cases compared to the matched group were less likely to receive surgical interventions and targeted biological therapy, and more likely to receive cytotoxic empiric chemotherapeutic agents. Having an occult GI tumour was associated with reduced OS and appeared to be a nonsignificant independent predictor of OS when adjusting for treatment differences. GI tumours are the most common occult primary tumours in men and the second most common in women. Patients with occult GI primary tumours are potentially being undertreated with available GI site-specific and targeted therapies.

Slowness in Movement Initiation is Associated with Proactive Inhibitory Network Dysfunction in Parkinson's Disease.

PubMed

Criaud, Marion; Poisson, Alice; Thobois, Stéphane; Metereau, Elise; Redouté, Jérôme; Ibarrola, Danièle; Baraduc, Pierre; Broussolle, Emmanuel; Strafella, Antonio P; Ballanger, Bénédicte; Boulinguez, Philippe

2016-04-02

Impairment in initiating movements in PD might be related to executive dysfunction associated with abnormal proactive inhibitory control, a pivotal mechanism consisting in gating movement initiation in uncertain contexts. Testing this hypothesis on the basis of direct neural-based evidence. Twelve PD patients on antiparkinsonian medication and fifteen matched healthy controls performed a simple reaction time task during event-related functional MRI scanning. For all subjects, the level of activation of SMA was found to predict RT on a trial-by-trial basis. The increase in movement initiation latency observed in PD patients with regard to controls was associated with pre-stimulus BOLD increases within several nodes of the proactive inhibitory network (caudate nucleus, precuneus, thalamus). These results provide physiological data consistent with impaired control of proactive inhibition over motor initiation in PD. Patients would be locked into a mode of control maintaining anticipated inhibition over willed movements even when the situation does not require action restraint. The functional and neurochemical bases of brain activity associated with executive settings need to be addressed thoroughly in future studies to better understand disabling symptoms that have few therapeutic options like akinesia.

DUAL STATE-PARAMETER UPDATING SCHEME ON A CONCEPTUAL HYDROLOGIC MODEL USING SEQUENTIAL MONTE CARLO FILTERS

NASA Astrophysics Data System (ADS)

Noh, Seong Jin; Tachikawa, Yasuto; Shiiba, Michiharu; Kim, Sunmin

Applications of data assimilation techniques have been widely used to improve upon the predictability of hydrologic modeling. Among various data assimilation techniques, sequential Monte Carlo (SMC) filters, known as "particle filters" provide the capability to handle non-linear and non-Gaussian state-space models. This paper proposes a dual state-parameter updating scheme (DUS) based on SMC methods to estimate both state and parameter variables of a hydrologic model. We introduce a kernel smoothing method for the robust estimation of uncertain model parameters in the DUS. The applicability of the dual updating scheme is illustrated using the implementation of the storage function model on a middle-sized Japanese catchment. We also compare performance results of DUS combined with various SMC methods, such as SIR, ASIR and RPF.

Accuracy of the initial endoscopic diagnosis in the discrimination of gastric ulcers: is endoscopic follow-up study always needed?

PubMed

Bustamante, Marco; Devesa, Francesc; Borghol, Abdul; Ortuño, Juan; Ferrando, Maria Jose

2002-07-01

Endoscopic follow-up study of gastric ulcers has been recommended routinely because of the possibility that a gastric neoplasm will be missed in the initial endoscopy. Some authors, most of them reporting data from areas of low gastric carcinoma incidence, have questioned this policy because of the low numbers of curable cancers detected and the high cost of such a program. To assess the accuracy of endoscopy diagnosis of gastric ulcers, and to evaluate the efficacy and cost of a gastric ulcer follow-up endoscopic program in an area with an intermediate incidence rate of gastric cancer. A retrospective study was used to identify all the gastroscopies in which a gastric ulcer had been diagnosed during a 6-year period. The endoscopic impression was compared with the histologic diagnosis, sensitivity, specificity, positive and negative predictive values, and the likelihood ratio. Patients who completed a follow-up program also were reviewed. For each neoplasm discovered, the number of endoscopies and global cost were calculated. In the 741 gastroscopies performed, 547 gastric ulcers were diagnosed in 529 patients. Biopsies were taken in 330 patients, in whom 341 gastric ulcers were found. At the index endoscopy, 41 gastric neoplasms (12.4%) were diagnosed. The accuracy of endoscopic malignancy diagnosis was as follows: positive predictive value of 0.68, negative predictive value of 0.98, sensitivity of 0.82, and specificity of 0.95. The likelihood ratio was 16. A total of 117 patients completed the follow-up program. Three new cases of gastric cancer (2.6%) were identified. In these three cases, the initial opinion of the endoscopist was uncertain. In the authors' experience, the cost of each gastric cancer diagnosed has been $4.653 (U.S. dollars). The endoscopic impression correlates with the histologic diagnosis even in a area of intermediate gastric cancer incidence. Endoscopic follow-up study may be restricted to cases of uncertain or malignant endoscopic impression.

Proton threshold states in the {sup 22}Na(p,{gamma}){sup 23}Mg reaction and astrophysical implications

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

Comisel, H.; Hategan, C.; Graw, G.

Proton threshold states in {sup 23}Mg are important for the astrophysically relevant proton capture reaction {sup 22}Na(p,{gamma}){sup 23}Mg. In the indirect determination of the resonance strength of the lowest states, which were not accessible by direct methods, some of the spin-parity-assignments remained experimentally uncertain. We have investigated these states with shell model, Coulomb displacement, and Thomas-Ehrman shift calculations. From the comparison of calculated and observed properties, we relate the lowest relevant resonance state at E{sub x}=7643 keV to an excited 3/2{sup +} state in accordance with a recent experimental determination by Jenkins et al. From this we deduce significantly improvedmore » values for the {sup 22}Na(p,{gamma}){sup 23}Mg reaction rate at stellar temperatures below T{sub 9}=0.1 K.« less

The early Earth atmosphere and early life catalysts.

PubMed

Ramírez Jiménez, Sandra Ignacia

2014-01-01

Homochirality is a property of living systems on Earth. The time, the place, and the way in which it appeared are uncertain. In a prebiotic scenario two situations are of interest: either an initial small bias for handedness of some biomolecules arouse and progressed with life, or an initial slight excess led to the actual complete dominance of the known chiral molecules. A definitive answer can probably never be given, neither from the fields of physics and chemistry nor biology. Some arguments can be advanced to understand if homochirality is necessary for the initiation of a prebiotic homochiral polymer chemistry, if this homochirality is suggesting a unique origin of life, or if a chiral template such as a mineral surface is always required to result in an enantiomeric excess. A general description of the early Earth scenario will be presented in this chapter, followed by a general description of some clays, and their role as substrates to allow the concentration and amplification of some of the building blocks of life.

Radiosensitivity of cancer-initiating cells and normal stem cells (or what the Heisenberg uncertainly principle has to do with biology).

PubMed

Woodward, Wendy Ann; Bristow, Robert Glen

2009-04-01

Mounting evidence suggests that parallels between normal stem cell biology and cancer biology may provide new targets for cancer therapy. Prospective identification and isolation of cancer-initiating cells from solid tumors has promoted the descriptive and functional identification of these cells allowing for characterization of their response to contemporary cancer therapies, including chemotherapy and radiation. In clinical radiation therapy, the failure to clinically eradicate all tumor cells (eg, a lack of response, partial response, or nonpermanent complete response by imaging) is considered a treatment failure. As such, biologists have explored the characteristics of the small population of clonogenic cancer cells that can survive and are capable of repopulating the tumor after subcurative therapy. Herein, we discuss the convergence of these clonogenic studies with contemporary radiosensitivity studies that use cell surface markers to identify cancer-initiating cells. Implications for and uncertainties regarding incorporation of these concepts into the practice of modern radiation oncology are discussed.

Scenario Planning to Identify Science Needs for the Management of Energy and Resource Development in the Arctic

NASA Astrophysics Data System (ADS)

Lassuy, D.

2013-12-01

The North Slope Science Initiative (NSSI) is an intergovernmental science collaboration forum in Arctic Alaska (USA). NSSI has initiated a 'Scenario Planning' effort with the focal question: 'What is the future of energy development, resource extraction, and associated support activities on the North Slope and adjacent seas through 2040?' With over 500 thousand square kilometers of land and sea, the area of the North Slope and adjacent seas is believed to have some of the largest oil, gas, and coal potential remaining in the United States, but it is also home to a diverse array of fish, wildlife, and plant resources that support a vibrant subsistence culture. Our scenario planning will involve a full and collaborative dialogue among a wide range of U.S. Arctic stakeholders, including Alaska Native subsistence users, local communities, academia, non-governmental organizations, and a variety of industries (oil and gas, mining, transportation, etc.) and government agencies (federal, state, local). The formulation of development scenarios and an understanding of their implications will provide a practical context for NSSI member agencies to make informed decisions about the research and monitoring that will be needed to sustain these resources and to plan for safe energy and resource development in the face of impending changes. The future of Arctic America is difficult to accurately predict, particularly in an era of intense pressures from both energy development and climate warming. However, it will almost surely be characterized by highly consequential and unprecedented changes. Complex and uncertain are appropriate descriptors of the Arctic and its future; and scenario planning has proven an effective tool to help engage diverse stakeholders in a focused dialogue and systematic thinking about plausible futures in complex and uncertain settings. The NSSI leadership recognized the critical need for this dialogue and has begun a scenario planning effort for the North Slope of Alaska and the adjacent Beaufort and Chukchi Seas. As currently designed, this NSSI scenario planning effort will encompass two broadly defined steps. We will engage local communities along with resource agencies, industry, non-governmental organizations, academia, and others with Arctic interests in exploring plausible future development activity (scenarios). Then we will undertake science- and traditional knowledge-informed explorations of the relevant research and monitoring that will be needed to detect, assess, and respond to the identified range of plausible development-driven changes on the North Slope and adjacent seas (strategies). The intent is for these strategies to then inform agency decisions about future investment in research and monitoring, and particularly to identify opportunities to collaborate in a manner that will benefit all involved parties. However, it is also important to note that the most important short- and long-term benefit of this scenario planning exercise may in fact be the strengthening of an involved and informed community of stakeholder participants, regardless of specific informational or strategic outcomes.

75 FR 60371 - Requirements of a Statement Disclosing Uncertain Tax Positions; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-30

... Requirements of a Statement Disclosing Uncertain Tax Positions; Correction AGENCY: Internal Revenue Service... the IRS to require corporations to file a schedule disclosing uncertain tax positions related to the tax return as required by the IRS. FOR FURTHER INFORMATION CONTACT: Kathryn Zuba, (202) 622-3400 (not...

Uncertain Times 2012: Afterschool Programs Still Struggling in Today's Economy

ERIC Educational Resources Information Center

Afterschool Alliance, 2012

2012-01-01

"Uncertain Times 2012," conducted by the Afterschool Alliance between April 25 and June 8, 2012, assesses the impact of economic conditions on afterschool programs. While many studies have evaluated the impact of programs, "Uncertain Times" is the only research to examine the fiscal health of afterschool programs and their…

Effect of risperidone versus haloperidol on emotional responding in schizophrenic patients.

PubMed

Fakra, E; Khalfa, S; Da Fonseca, D; Besnier, N; Delaveau, P; Azorin, J M; Blin, O

2008-10-01

Studies on emotional processing report that schizophrenic patients present a specific pattern of emotional responding that usually includes deficits in emotional expressiveness, increased feelings of unpleasant emotion but decreased feelings of pleasant emotion, and increased physiological reactivity. However, studies have rarely controlled the nature of antipsychotic medication. Yet, the influence of these drugs on emotional response is uncertain and could vary depending on their pharmacological profile. This prospective and randomized study aimed to compare the effects of an atypical antipsychotic, risperidone, to a typical one, haloperidol, on patients' emotional responding during an emotional induction task. Twenty-five schizophrenic patients underwent two emotional and clinical evaluations: one before treatment initiation and a second 4 weeks after. Emotional states of fear, sadness, anger, joy, and disgust were induced, as well as a neutral baseline state. Video recordings of patients during the induction task allowed for assessment of emotional expressiveness. Self-reports and measures of skin conductance and heart rate were performed to determine both subjective and physiological reactions to emotional experience. Compared to haloperidol, risperidone did not reduce patients' facial expressiveness, decreased physiological reactivity, and decreased experience of unpleasant emotion but maintained experience of pleasant emotion. Emotional expressiveness was negatively correlated to parkisonism. Our preliminary results suggest that atypical antipsychotics allow for better-adapted patterns of emotional responding than typical ones do. We suggest that this effect is due to reduced striatal D2 blockade, therefore, attenuating akinesia, coupled with increased 5HT and DA levels in prefrontal cortex, which improves emotional regulation.

Volumetric Properties and Fluid Phase Equilibria of CO2 + H2O

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

Capobianco, Ryan; Gruszkiewicz, Miroslaw; Wesolowski, David J

2013-01-01

The need for accurate modeling of fluid-mineral processes over wide ranges of temperature, pressure and composition highlighted considerable uncertainties of available property data and equations of state, even for the CO2 + H2O binary system. In particular, the solubility, activity, and ionic dissociation equilibrium data for the CO2-rich phase, which are essential for understanding dissolution/precipitation, fluid-matrix reactions, and solute transport, are uncertain or missing. In this paper we report the results of a new experimental study of volumetric and phase equilibrium properties of CO2 + H2O, to be followed by measurements for bulk and confined multicomponent fluid mixtures. Mixture densitiesmore » were measured by vibrating tube densimetry (VTD) over the entire composition range at T = 200 and 250 C and P = 20, 40, 60, and 80 MPa. Initial analysis of the mutual solubilities, determined from volumetric data, shows good agreement with earlier results for the aqueous phase, but finds that the data of Takenouchi and Kennedy (1964) significantly overestimated the solubility of water in supercritical CO2 (by a factor of more than two at 200 C). Resolving this well-known discrepancy will have a direct impact on the accuracy of predictive modeling of CO2 injection in geothermal reservoirs and geological carbon sequestration through improved equations of state, needed for calibration of predictive molecular-scale models and large-scale reactive transport simulations.« less

Alcohol's effects on emotionally motivated attention, defensive reactivity and subjective anxiety during uncertain threats.

PubMed

Bradford, Daniel E; Motschman, Courtney A; Starr, Mark J; Curtin, John J

2017-11-01

Developing a better understanding of how and under what circumstances alcohol affects the emotions, cognitions and neural functions that precede and contribute to dangerous behaviors during intoxication may help to reduce their occurrence. Alcohol intoxication has recently been shown to reduce defensive reactivity and anxiety more during uncertain vs certain threat. However, alcohol's effects on emotionally motivated attention to these threats are unknown. Alcohol may disrupt both affective response to and attentional processing of uncertain threats making intoxicated individuals less able to avoid dangerous and costly behaviors. To test this possibility, we examined the effects of a broad range of blood alcohol concentrations on 96 participants' sub-cortically mediated defensive reactivity (startle potentiation), retrospective subjective anxiety (self-report) and cortically assessed emotionally motivated attention (probe P3 event related potential) while they experienced visually cued uncertain and certain location electric shock threat. As predicted, alcohol decreased defensive reactivity and subjective anxiety more during uncertain vs certain threat. In a novel finding, alcohol dampened emotionally motivated attention during uncertain but not certain threat. This effect appeared independent of alcohol's effects on defensive reactivity and subjective anxiety. These results suggest that alcohol intoxication dampens processing of uncertain threats while leaving processing of certain threats intact. © The Author (2017). Published by Oxford University Press.

Performance recovery of a class of uncertain non-affine systems with unmodelled dynamics: an indirect dynamic inversion method

NASA Astrophysics Data System (ADS)

Yi, Bowen; Lin, Shuyi; Yang, Bo; Zhang, Weidong

2018-02-01

This paper presents an output feedback indirect dynamic inversion (IDI) approach for a class of uncertain nonaffine systems with input unmodelled dynamics. Compared with previous approaches to achieve performance recovery, the proposed method aims at dealing with a broader class of nonaffine-in-control systems with triangular structure. An IDI state feedback law is designed first, in which less knowledge of the model plant is needed compared to earlier approximate dynamic inversion methods, thus yielding more robust performance. After that, an extended high-gain observer is designed to accomplish the task with output feedback. Finally, we prove that the designed IDI controller is equivalent to an adaptive proportional-integral (PI) controller, with respect to both time response equivalence and robustness equivalence. The conclusion implies that for the studied strict-feedback non-affine systems with unmodelled dynamics, there always exits a PI controller to stabilise the systems. The effectiveness and benefits of the designed approach are verified by three examples.

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.

Future hotspots of increasing temperature variability in tropical countries

NASA Astrophysics Data System (ADS)

Bathiany, S.; Dakos, V.; Scheffer, M.; Lenton, T. M.

2017-12-01

Resolving how climate variability will change in future is crucial to determining how challenging it will be for societies and ecosystems to adapt to climate change. We show that the largest increases in temperature variability - that are robust between state-of-the art climate models - are concentrated in tropical countries. On average, temperature variability increases by 15% per degree of global warming in Amazonia and Southern Africa during austral summer, and by up to 10% °C-1 in the Sahel, India and South East Asia. Southern hemisphere changes can be explained by drying soils, whereas shifts in atmospheric structure play a more important role in the Northern hemisphere. These robust regional changes in variability are associated with monthly timescale events, whereas uncertain changes in inter-annual modes of variability make the response of global temperature variability uncertain. Our results suggest that regional changes in temperature variability will create new inequalities in climate change impacts between rich and poor nations.

Improved prescribed performance control for air-breathing hypersonic vehicles with unknown deadzone input nonlinearity.

PubMed

Wang, Yingyang; Hu, Jianbo

2018-05-19

An improved prescribed performance controller is proposed for the longitudinal model of an air-breathing hypersonic vehicle (AHV) subject to uncertain dynamics and input nonlinearity. Different from the traditional non-affine model requiring non-affine functions to be differentiable, this paper utilizes a semi-decomposed non-affine model with non-affine functions being locally semi-bounded and possibly in-differentiable. A new error transformation combined with novel prescribed performance functions is proposed to bypass complex deductions caused by conventional error constraint approaches and circumvent high frequency chattering in control inputs. On the basis of backstepping technique, the improved prescribed performance controller with low structural and computational complexity is designed. The methodology guarantees the altitude and velocity tracking error within transient and steady state performance envelopes and presents excellent robustness against uncertain dynamics and deadzone input nonlinearity. Simulation results demonstrate the efficacy of the proposed method. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Tendency to occupy a statistically dominant spatial state of the flow as a driving force for turbulent transition.

PubMed

Chekmarev, Sergei F

2013-03-01

The transition from laminar to turbulent fluid motion occurring at large Reynolds numbers is generally associated with the instability of the laminar flow. On the other hand, since the turbulent flow characteristically appears in the form of spatially localized structures (e.g., eddies) filling the flow field, a tendency to occupy such a structured state of the flow cannot be ruled out as a driving force for turbulent transition. To examine this possibility, we propose a simple analytical model that treats the flow as a collection of localized spatial structures, each of which consists of elementary cells in which the behavior of the particles (atoms or molecules) is uncorrelated. This allows us to introduce the Reynolds number, associating it with the ratio between the total phase volume for the system and that for the elementary cell. Using the principle of maximum entropy to calculate the most probable size distribution of the localized structures, we show that as the Reynolds number increases, the elementary cells group into the localized structures, which successfully explains turbulent transition and some other general properties of turbulent flows. An important feature of the present model is that a bridge between the spatial-statistical description of the flow and hydrodynamic equations is established. We show that the basic assumptions underlying the model, i.e., that the particles are indistinguishable and elementary volumes of phase space exist in which the state of the particles is uncertain, are involved in the derivation of the Navier-Stokes equation. Taking into account that the model captures essential features of turbulent flows, this suggests that the driving force for the turbulent transition is basically the same as in the present model, i.e., the tendency of the system to occupy a statistically dominant state plays a key role. The instability of the flow at high Reynolds numbers can then be a mechanism to initiate structural rearrangement of the flow to find this state.

Controls on SOC across space and time: Models with different acclimation schemes make similar spatial predictions but divergent warming predictions

NASA Astrophysics Data System (ADS)

Abramoff, R. Z.; Torn, M. S.; Georgiou, K.; Tang, J.; Riley, W. J.

2017-12-01

Researchers use spatial gradients to estimate long-term ecosystem responses to perturbations. This approach is commonly applied to soil organic carbon (SOC) stocks which change slowly but store the majority of terrestrial carbon. Climate warming may reduce SOC stocks if higher temperatures increase decomposition rates. Yet, it is uncertain how vulnerable SOC is to warming, and whether the same factors - such as organo-mineral associations, climate, or plant inputs - determine SOC stocks across space and time. In order to test the "space for time" concept, we developed two versions of the Substrate-Mineral-Microbe Soil (SuMMS) model - one with microbial temperature acclimation and one without - to analyze observed SOC stocks at 24 sites spanning a wide range of soil types and climate. Both model predictions of SOC were strongly correlated with observations (R2 > 0.9), because mineral sorption capacity was the dominant control over steady-state SOC stock as determined by a Random Forest model. However, the two model versions made fundamentally different predictions of the change in SOC following 5°C soil warming from 2016 to 2100 because the initial mean annual temperature (MAT) was the dominant control over the SOC response. The model with microbial acclimation predicted that SOC would decline 10% at all sites along the transect, while the model with no acclimation predicted large surface SOC losses at high latitude sites and SOC gains at low latitude sites where microbial exoenzymes were already at or near their temperature optimum. These simulations suggest that gradient studies cannot be used to infer site-level responses to warming, because the dominant controls on SOC at steady state (i.e., mineral sorption capacity) are different than the dominant controls on the SOC response to a warming perturbation (i.e., initial MAT, capacity for acclimation).

Hydromechanical Modeling of Fluid Flow in the Lower Crust

NASA Astrophysics Data System (ADS)

Connolly, J.

2011-12-01

The lower crust lies within an ambiguous rheological regime between the brittle upper crust and ductile sub-lithospheric mantle. This ambiguity has allowed two schools of thought to develop concerning the nature of fluid flow in the lower crust. The classical school holds that lower crustal rocks are inviscid and that any fluid generated by metamorphic devolatilization is squeezed out of rocks as rapidly as it is produced. According to this school, permeability is a dynamic property and fluid flow is upward. In contrast, the modern school uses concepts from upper crustal hydrology that presume implicitly, if not explicitly, that rocks are rigid or, at most, brittle. For the modern school, the details of crustal permeability determine fluid flow and as these details are poorly known almost anything is possible. Reality, to the extent that it is reflected by inference from field studies, offers some support to both schools. In particular, evidence of significant lateral and channelized fluid flow are consistent with flow in rigid media, while evidence for short (104 - 105 y) grain-scale fluid-rock interaction during much longer metamorphic events, suggests that reaction-generated grain-scale permeability is sealed rapidly by compaction; a phenomenon that is also essential to prevent extensive retrograde metamorphism. These observations provide a compelling argument for recognizing in conceptual models of lower crustal fluid flow that rocks are neither inviscid nor rigid, but compact by viscous mechanisms on a finite time-scale. This presentation will review the principle consequences of, and obstacles to, incorporating compaction in such models. The role of viscous compaction in the lower crust is extraordinarily uncertain, but ignoring this uncertainty in models of lower crustal fluid flow does not make the models any more certain. Models inevitably invoke an initial steady state hydraulic regime. This initial steady state is critical to model outcomes because it determines the compaction time and length scales and, thereby, the response of the system to perturbations. Unfortunately, because metamorphic devolatilization is the most probable source of lower crustal fluids, the assumption of an initial steady state leaves much to be desired. In truth, in the modeling of lower crustal fluid flow, less is known about the initial state than is known about possible perturbations to it, e.g., metamorphic fluid production. Compaction is a bad and good news story. The bad news is that local flow patterns may be influenced by unknowable details; the good news is that compaction-driven fluid flow has a tendency to self-organize. Self-organization eliminates the dependence on details that are present on spatial or temporal scales that are smaller than the compaction length and time scales. Porosity waves are the mechanism for this self-organization, through which dilational deformation is localized in time and space to create pathways for fluid expulsion. The resulting flow patterns are sensitive to material properties and initial state, thus, inversion of natural flow patterns offers the greatest hope for constraining the compaction scales. Knowledge of these scales is also important because they limit the influence of external forcings on flow patterns, e.g., a shear zone may induce lateral or downward fluid flow, but only on the compaction time and length scales.

Appropriate Use Criteria in Dermatopathology: Initial Recommendations from the American Society of Dermatopathology.

PubMed

Vidal, Claudia I; Armbrect, Eric A; Andea, Aleodor A; Bohlke, Angela K; Comfere, Nneka I; Hughes, Sarah R; Kim, Jinah; Kozel, Jessica A; Lee, Jason B; Linos, Konstantinos; Litzner, Brandon R; Missall, Tricia A; Novoa, Roberto A; Sundram, Uma; Swick, Brian L; Hurley, M Yadira; Alam, Murad; Argenyi, Zsolt; Duncan, Lyn M; Elston, Dirk M; Emanuel, Patrick O; Ferringer, Tammie; Fung, Maxwell A; Hosler, Gregory A; Lazar, Alexander J; Lowe, Lori; Plaza, Jose A; Prieto, Victor G; Robinson, June K; Schaffer, Andras; Subtil, Antonio; Wang, Wei-Lien

2018-04-21

Appropriate use criteria (AUC) provide physicians guidance in test selection, can affect health care delivery, reimbursement policy, and physician decision-making. The American Society of Dermatopathology (ASDP), with input from the American Academy of Dermatology (AAD) and the College of American Pathologists (CAP), sought to develop AUC in dermatopathology. The RAND/UCLA appropriateness methodology, which combines evidence-based medicine, clinical experience and expert judgment, was used to develop AUC in dermatopathology. With the number of ratings predetermined at 3, AUC were developed for 211 clinical scenarios (CS) involving 12 ancillary studies (AS). Consensus was reached for 188 (89%) CS, with 93 (44%) considered "usually appropriate", 52 (25%) "rarely appropriate", and 43 (20%) "uncertain appropriateness". The methodology requires a focus on appropriateness without comparison between tests and irrespective of cost. The ultimate decision of when to order specific test rests with the physician and is one where the expected benefit exceeds the negative consequences. This publication outlines the recommendation of appropriateness - AUC for 12 tests used in dermatopathology. Importantly, these recommendations may change considering new evidence. Results deemed "uncertain appropriateness" and where consensus was not reached may benefit from further research. Copyright © 2018. Published by Elsevier Inc.

Waterway Shielding System and Method

DTIC Science & Technology

2003-04-30

In early October 12 2002, A French VLCC (Very Large Crude Carrier) chartered by 13 Malaysian state oil company Petronas was attacked by terrorist 14...Combiner 72 may provide a 11 processor with algorithms that are used to add candidates when 12 uncertain and delete candidates when analysis data is fairly...commercial interests that normally have a need to know where 18 shipments of interest on any particular ship are presently 19 located, where competitor

JPRS Report, Science & Technology, USSR: Science & Technology Policy

DTIC Science & Technology

1988-11-07

progressive taxation to the payments to the centralized fund and to the reserves of the ministry. In addition to deductions from the accounting profit... taxation ." As we see, the decree in no uncertain terms asserted the priority of the state right to the use of inventions. A compulsory procedure of its...corresponding prob- lems and tasks, requiring the receptivity and elasticity of the international socialist division of labor with respect to the new

Russia's Uncertain Transition: Challenges for U.S. Policy. Fifth Edition. Teacher Resource Book [and Student Text]. Public Policy Debate in the Classroom. Choices for the 21st Century.

ERIC Educational Resources Information Center

Fox, Sarah Cleveland

Since the end of the Cold War, and more recently since September 11, 2001, relations between the United States and Russia have reached new levels of cooperation and accommodation. At the same time, many important developments in Russia remain cloaked by government intrigue or obscured by the complexity of Russia's political and cultural past. This…

Hollow Force, Hollow Metaphor: Assessing the Current Defense Drawdown

DTIC Science & Technology

2016-04-04

better prioritized. Army Readiness Secretary of the Army John McHugh and Chief of Staff of the Army (CSA), General Raymond Odierno, assessed in...forming the Army’s readiness narrative— Army leaders see the cuts as inconsistent with an uncertain and volatile strategic environment. McHugh and...John M. McHugh and Raymond T. Odierno, statement made on the Posture of the United States Army, on March 18, 2015, to the Senate Armed Services

Hollow Force, Hollow Metaphor: Assessing The Current Defense Drawdown

DTIC Science & Technology

2016-04-04

better prioritized. Army Readiness Secretary of the Army John McHugh and Chief of Staff of the Army (CSA), General Raymond Odierno, assessed in...forming the Army’s readiness narrative— Army leaders see the cuts as inconsistent with an uncertain and volatile strategic environment. McHugh and...John M. McHugh and Raymond T. Odierno, statement made on the Posture of the United States Army, on March 18, 2015, to the Senate Armed Services

A Qualitative Study of Affordability: Virginia and San Antonio Class Programs

DTIC Science & Technology

2014-06-01

that actual costs and operational tempos resemble original assumptions is the most uncertain aspect of sustainment costs. Operators must respond to a...SSN 774 through SSN 787; this represents 47% of the total inventory, a typical variation for ships from the acquisition standard of 10%. Even... Goldberg , M., … MacKinnon, M. (1994). The U.S. submarine production base (MR-456-OSD). Santa Monica, CA: RAND. Blickstein, I. United States. Department

21 CFR 20.47 - Situations in which confidentiality is uncertain.

Code of Federal Regulations, 2011 CFR

2011-04-01

... submitted or divulged the data or information or who would be affected by disclosure before determining whether or not such data or information is available for public disclosure. [42 FR 15616, Mar. 22, 1977... uncertain. In situations where the confidentiality of data or information is uncertain and there is a...

21 CFR 20.47 - Situations in which confidentiality is uncertain.

Code of Federal Regulations, 2014 CFR

2014-04-01

... submitted or divulged the data or information or who would be affected by disclosure before determining whether or not such data or information is available for public disclosure. [42 FR 15616, Mar. 22, 1977... uncertain. In situations where the confidentiality of data or information is uncertain and there is a...

21 CFR 20.47 - Situations in which confidentiality is uncertain.

Code of Federal Regulations, 2012 CFR

2012-04-01

... submitted or divulged the data or information or who would be affected by disclosure before determining whether or not such data or information is available for public disclosure. [42 FR 15616, Mar. 22, 1977... uncertain. In situations where the confidentiality of data or information is uncertain and there is a...

21 CFR 20.47 - Situations in which confidentiality is uncertain.

Code of Federal Regulations, 2013 CFR

2013-04-01

... submitted or divulged the data or information or who would be affected by disclosure before determining whether or not such data or information is available for public disclosure. [42 FR 15616, Mar. 22, 1977... uncertain. In situations where the confidentiality of data or information is uncertain and there is a...

21 CFR 20.47 - Situations in which confidentiality is uncertain.

Code of Federal Regulations, 2010 CFR

2010-04-01

... submitted or divulged the data or information or who would be affected by disclosure before determining whether or not such data or information is available for public disclosure. [42 FR 15616, Mar. 22, 1977... uncertain. In situations where the confidentiality of data or information is uncertain and there is a...

Millennial Teachers and Multiculturalism: Considerations for Teaching in Uncertain Times

ERIC Educational Resources Information Center

Hallman, Heidi L.

2017-01-01

Purpose: This paper aims to explore the intersection of generational traits of millennial teachers, multiculturalism and teaching in an era of Uncertain Times. Uncertain Times, as a framework for the paper, characterizes changing aspects of the current era in which we live, such as the rise of the internet and interconnectivity, globalization and…

Six sigma for revenue retrieval.

PubMed

Plonien, Cynthia

2013-01-01

Deficiencies in revenue retrieval due to failures in obtaining charges have contributed to a negative bottom line for numerous hospitals. Improving documentation practices through a Six Sigma process improvement initiative can minimize opportunities for errors through reviews and instill structure for compliance and consistency. Commitment to the Six Sigma principles with continuous monitoring of outcomes and constant communication of results to departments, management, and payers is a strong approach to reducing the financial impact of denials on an organization's revenues and expenses. Using Six Sigma tools can help improve the organization's financial performance not only for today, but also for health care's uncertain future.

Simple bone cyst of mandible mimicking periapical cyst.

PubMed

Hs, Charan Babu; Rai, Bhagawan Das; Nair, Manju A; Astekar, Madhusudan S

2012-05-29

Simple bone cysts (SBC) are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient.

Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET) Measurements

NASA Technical Reports Server (NTRS)

Schuster, Gregory L.; Dubovik, Oleg; Holben, Brent N.; Clothiaux, Eugene E.

2006-01-01

The carbon emissions inventories used to initialize transport models and general circulation models are highly parameterized, and created on the basis of multiple sparse datasets (such as fuel use inventories and emission factors). The resulting inventories are uncertain by at least a factor of 2, and this uncertainty is carried forward to the model output. [Bond et al., 1998, Bond et al., 2004, Cooke et al., 1999, Streets et al., 2001] Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output on a continuous basis.

CKD of Uncertain Etiology: A Systematic Review

PubMed Central

Mohottige, Dinushika; Isenburg, Megan Von; Jeuland, Marc; Patel, Uptal D.; Stanifer, John W.

2016-01-01

Background and objectives Epidemics of CKD of uncertain etiology (CKDu) are emerging around the world. Highlighting common risk factors for CKD of uncertain etiology across various regions and populations may be important for health policy and public health responses. Design, setting, participants, & measurements We searched PubMed, Embase, Scopus and Web of Science databases to identify published studies on CKDu. The search was generated in January of 2015; no language or date limits were used. We used a vote-counting method to evaluate exposures across all studies. Results We identified 1607 articles, of which 26 met inclusion criteria. Eighteen (69%) were conducted in known CKDu–endemic countries: Sri Lanka (38%), Nicaragua (19%), and El Salvador (12%). The other studies were from India, Japan, Australia, Mexico, Sweden, Tunisia, Tanzania, and the United States. Heavy metals, heat stress, and dietary exposures were reported across all geographic regions. In south Asia, family history, agrochemical use, and heavy metal exposures were reported most frequently, whereas altitude and temperature were reported only in studies from Central America. Across all regions, CKDu was most frequently associated with a family history of CKDu, agricultural occupation, men, middle age, snake bite, and heavy metal exposure. Conclusions Studies examining etiologies of CKDu have reported many exposures that are heterogeneous and vary by region. To identify etiologies of CKDu, designing consistent and comparative multisite studies across high-risk populations may help elucidate the importance of region–specific versus global risk factors. PMID:26712810

CKD of Uncertain Etiology: A Systematic Review.

PubMed

Lunyera, Joseph; Mohottige, Dinushika; Von Isenburg, Megan; Jeuland, Marc; Patel, Uptal D; Stanifer, John W

2016-03-07

Epidemics of CKD of uncertain etiology (CKDu) are emerging around the world. Highlighting common risk factors for CKD of uncertain etiology across various regions and populations may be important for health policy and public health responses. We searched PubMed, Embase, Scopus and Web of Science databases to identify published studies on CKDu. The search was generated in January of 2015; no language or date limits were used. We used a vote-counting method to evaluate exposures across all studies. We identified 1607 articles, of which 26 met inclusion criteria. Eighteen (69%) were conducted in known CKDu-endemic countries: Sri Lanka (38%), Nicaragua (19%), and El Salvador (12%). The other studies were from India, Japan, Australia, Mexico, Sweden, Tunisia, Tanzania, and the United States. Heavy metals, heat stress, and dietary exposures were reported across all geographic regions. In south Asia, family history, agrochemical use, and heavy metal exposures were reported most frequently, whereas altitude and temperature were reported only in studies from Central America. Across all regions, CKDu was most frequently associated with a family history of CKDu, agricultural occupation, men, middle age, snake bite, and heavy metal exposure. Studies examining etiologies of CKDu have reported many exposures that are heterogeneous and vary by region. To identify etiologies of CKDu, designing consistent and comparative multisite studies across high-risk populations may help elucidate the importance of region-specific versus global risk factors. Copyright © 2016 by the American Society of Nephrology.

Characterisation of Black Carbon (BC) mixing state and flux in Beijing using single particle measurements.

NASA Astrophysics Data System (ADS)

Joshi, Rutambhara; Liu, Dantong; Allan, James; Coe, Hugh; Flynn, Michael; Broda, Kurtis; Olfert, Jason; Irwin, Martin; Sun, Yele; Fu, Pingqing; Wang, Junfeng; Ge, Xinlei; Langford, Ben; Nemitz, Eiko; Mullinger, Neil

2017-04-01

BC is generated by the incomplete combustion of carbonaceous fuels and it is an important component of fine PM2.5. In the atmosphere BC particles have a complex structure and its mixing state has crucial impact on optical properties. Quantifying the sources and emissions of black carbon in urban environments is important and presently uncertain, particularly in megacities undergoing rapid growth and change in emissions. During the winter of 2016 (10th Nov-10th Dec) the BC was characterised as part of a large joint UK-China field experiment in Beijing. This paper focuses on understanding the mixing state of BC as well as identification and quantification of BC sources. We used a combination of a Centrifugal Particle Mass Analyser (CPMA) and a Single Particle Soot Photometer (SP2) to uniquely quantify the morphology independent mass of single refractory BC particles and their coating content. The CPMA allows us to select pre-charged aerosol particles according to their mass to charge ratio and the SP2 provides information on the mass of refractory BC through a laser-induced incandescence method. Furthermore, another SP2 was used to measure the BC flux at 100m height using the Eddy Covariance method. We have successfully gathered 4 weeks of continuous measurements which include several severe pollution events in Beijing. Here we present preliminary results, characterising the distribution of coating mass on BC particles in Beijing and linking this to the main sources of BC in the city. We will provide initial estimates of the BC flux over a several kilometre footprint. Such analysis will provide important information for the further investigation of source distribution, emission, lifetime and optical properties of BC under complex environments in Beijing.

Reliability-Based Control Design for Uncertain Systems

NASA Technical Reports Server (NTRS)

Crespo, Luis G.; Kenny, Sean P.

2005-01-01

This paper presents a robust control design methodology for systems with probabilistic parametric uncertainty. Control design is carried out by solving a reliability-based multi-objective optimization problem where the probability of violating design requirements is minimized. Simultaneously, failure domains are optimally enlarged to enable global improvements in the closed-loop performance. To enable an efficient numerical implementation, a hybrid approach for estimating reliability metrics is developed. This approach, which integrates deterministic sampling and asymptotic approximations, greatly reduces the numerical burden associated with complex probabilistic computations without compromising the accuracy of the results. Examples using output-feedback and full-state feedback with state estimation are used to demonstrate the ideas proposed.

JHPPL workshop on Medicaid fiscal and governance issues: objectives and themes.

PubMed

Long, Peter V; Campbell, Andrea Louise

2013-08-01

At a November 2012 workshop, state health policy officials, other Medicaid and insurance exchange practitioners, and health policy researchers discussed issues surrounding the implementation and sustainability of Medicaid expansion and insurance exchange coordination under the Patient Protection and Affordable Care Act (PPACA). Foremost were concerns about (1) intergovernmental relations (states experiencing uncertain information, lack of coordination among federal agencies, and limited resources to take on new responsibilities under the PPACA), and (2) policy design (new issues such as Medicaid exchange coordination on top of preexisting Medicaid challenges). JHPPL has proposed the creation of a research network to develop policy options and share strategies and best practices.

Formal Verification of Safety Buffers for Sate-Based Conflict Detection and Resolution

NASA Technical Reports Server (NTRS)

Herencia-Zapana, Heber; Jeannin, Jean-Baptiste; Munoz, Cesar A.

2010-01-01

The information provided by global positioning systems is never totally exact, and there are always errors when measuring position and velocity of moving objects such as aircraft. This paper studies the effects of these errors in the actual separation of aircraft in the context of state-based conflict detection and resolution. Assuming that the state information is uncertain but that bounds on the errors are known, this paper provides an analytical definition of a safety buffer and sufficient conditions under which this buffer guarantees that actual conflicts are detected and solved. The results are presented as theorems, which were formally proven using a mechanical theorem prover.

Space biology initiative program definition review. Trade study 2: Prototype utilization in the development of space biology hardware

NASA Technical Reports Server (NTRS)

Jackson, L. Neal; Crenshaw, John, Sr.; Schulze, Arthur E.; Wood, H. J., Jr.

1989-01-01

The objective was to define the factors which space flight hardware developers and planners should consider when determining: (1) the number of hardware units required to support program; (2) design level of the units; and (3) most efficient means of utilization of the units. The analysis considered technology risk, maintainability, reliability, and safety design requirements for achieving the delivery of highest quality flight hardware. Relative cost impacts of the utilization of prototyping were identified. The development of Space Biology Initiative research hardware will involve intertwined hardware/software activities. Experience has shown that software development can be an expensive portion of a system design program. While software prototyping could imply the development of a significantly different end item, an operational system prototype must be considered to be a combination of software and hardware. Hundreds of factors were identified that could be considered in determining the quantity and types of prototypes that should be constructed. In developing the decision models, these factors were combined and reduced by approximately ten-to-one in order to develop a manageable structure based on the major determining factors. The Baseline SBI hardware list of Appendix D was examined and reviewed in detail; however, from the facts available it was impossible to identify the exact types and quantities of prototypes required for each of these items. Although the factors that must be considered could be enumerated for each of these pieces of equipment, the exact status and state of development of the equipment is variable and uncertain at this time.

Comparison of the epidemiologic features and patterns of initial care for prostate cancer between public and private institutions: a survey by the Brazilian Society of Urology.

PubMed

Nardi, Aguinaldo Cesar; Reis, Rodolfo Borges dos; Zequi, Stenio de Cassio; Nardozza, Archimedes

2012-01-01

To describe the epidemiological features and patterns of initial care for prostate cancer at public and private institutions in the State of Sao Paulo, Brazil. A total of 1,082 physicians affiliated to the Sao Paulo Section of the Brazilian Society of Urology were invited to participate in this cross-sectional, web-based survey. Between September 2004 and September 2005, participating urologists entered data on demographic, clinical and pathological characteristics of patients diagnosed with prostate cancer in their practice. Data on patients attended at public institutions were analyzed and compared with those patients attended at private practice. One hundred and ten society members contributed with data from 1915 patients, 1026 (53.6%) of whom from public institutions. When compared with patients attended at private institutions, those attended at public institutions were older and more likely to be black, had higher serum prostate specific antigen (PSA) levels, had a higher probability of being diagnosed with metastatic disease, but were less likely to undergo prostatectomy (all P < 0.001). In multivariate analysis, age, biopsy Gleason score, and being attended at a public institution were independently associated with metastatic disease upon diagnosis. The significant predictors of nonsurgical treatment were age, black race, and higher serum levels of PSA. A statewide registry provides valuable information regarding patient demographics, clinical features, and patterns of care. The results of this study suggest that significant disparities exist for patients with prostate cancer attended at different health-care systems. The relative contribution of biological versus socioeconomic features remains uncertain.

Reconciling newborn screening and a novel splice variant in BTD associated with partial biotinidase deficiency: A BabySeq Project case report.

PubMed

Murry, Jaclyn B; Machini, Kalotina; Ceyhan-Birsoy, Ozge; Kritzer, Amy; Krier, Joel B; Lebo, Matthew S; Fayer, Shawn; Genetti, Casie A; Vannoy, Grace E; Yu, Timothy W; Agrawal, Pankaj B; Parad, Richard B; Holm, Ingrid A; McGuire, Amy L; Green, Robert C; Beggs, Alan H; Rehm, Heidi L; Project, The BabySeq

2018-05-04

Here, we report a newborn female infant from the well-baby cohort of the BabySeq Project who was identified with compound heterozygous BTD gene variants. The two identified variants included a well-established pathogenic variant (c.1612C>T, p.Arg538Cys) that causes profound biotinidase deficiency (BTD) in homozygosity. In addition, a novel splice variant (c.44+1G>A, p.?) was identified in the invariant splice donor region of intron 1, potentially predictive of loss of function. The novel variant was predicted to impact splicing of exon 1; however, given the absence of any reported pathogenic variants in exon 1 and the presence of alternative splicing with exon 1 absent in most tissues in the GTEx database, we assigned an initial classification of uncertain significance. Follow-up medical record review of state mandated newborn screen (NBS) results revealed an initial out-of-range biotinidase activity level. Levels from a repeat NBS sample barely passed cut-off into the normal range. To determine whether the infant was biotinidase deficient, subsequent diagnostic enzyme activity testing was performed, confirming partial BTD, and resulted in a change of management for this patient. This led to reclassification of the novel splice variant based on these results. In conclusion, combining the genetic and NBS results together prompted clinical follow-up that confirmed partial biotinidase deficiency, and informed this novel splice site's reclassification emphasizing the importance of combining iterative genetic and phenotypic evaluations. Cold Spring Harbor Laboratory Press.

State Estimation for Tensegrity Robots

NASA Technical Reports Server (NTRS)

Caluwaerts, Ken; Bruce, Jonathan; Friesen, Jeffrey M.; Sunspiral, Vytas

2016-01-01

Tensegrity robots are a class of compliant robots that have many desirable traits when designing mass efficient systems that must interact with uncertain environments. Various promising control approaches have been proposed for tensegrity systems in simulation. Unfortunately, state estimation methods for tensegrity robots have not yet been thoroughly studied. In this paper, we present the design and evaluation of a state estimator for tensegrity robots. This state estimator will enable existing and future control algorithms to transfer from simulation to hardware. Our approach is based on the unscented Kalman filter (UKF) and combines inertial measurements, ultra wideband time-of-flight ranging measurements, and actuator state information. We evaluate the effectiveness of our method on the SUPERball, a tensegrity based planetary exploration robotic prototype. In particular, we conduct tests for evaluating both the robot's success in estimating global position in relation to fixed ranging base stations during rolling maneuvers as well as local behavior due to small-amplitude deformations induced by cable actuation.

40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

Code of Federal Regulations, 2010 CFR

2010-07-01

... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to conduct... on the Inventory, in § 725.239 or in subpart M of this part. (1) Confidential identity or use. In...

40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

Code of Federal Regulations, 2012 CFR

2012-07-01

... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to conduct... on the Inventory, in § 725.239 or in subpart M of this part. (1) Confidential identity or use. In...

40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

Code of Federal Regulations, 2014 CFR

2014-07-01

... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to conduct... on the Inventory, in § 725.239 or in subpart M of this part. (1) Confidential identity or use. In...

40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

Code of Federal Regulations, 2013 CFR

2013-07-01

... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to conduct... on the Inventory, in § 725.239 or in subpart M of this part. (1) Confidential identity or use. In...

40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

Code of Federal Regulations, 2011 CFR

2011-07-01

... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to conduct... on the Inventory, in § 725.239 or in subpart M of this part. (1) Confidential identity or use. In...

Uncertain programming models for portfolio selection with uncertain returns

NASA Astrophysics Data System (ADS)

Zhang, Bo; Peng, Jin; Li, Shengguo

2015-10-01

In an indeterminacy economic environment, experts' knowledge about the returns of securities consists of much uncertainty instead of randomness. This paper discusses portfolio selection problem in uncertain environment in which security returns cannot be well reflected by historical data, but can be evaluated by the experts. In the paper, returns of securities are assumed to be given by uncertain variables. According to various decision criteria, the portfolio selection problem in uncertain environment is formulated as expected-variance-chance model and chance-expected-variance model by using the uncertainty programming. Within the framework of uncertainty theory, for the convenience of solving the models, some crisp equivalents are discussed under different conditions. In addition, a hybrid intelligent algorithm is designed in the paper to provide a general method for solving the new models in general cases. At last, two numerical examples are provided to show the performance and applications of the models and algorithm.

Low cloud properties influenced by cosmic rays

PubMed

Marsh; Svensmark

2000-12-04

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (

Flight control application of new stability robustness bounds for linear uncertain systems

NASA Technical Reports Server (NTRS)

Yedavalli, Rama K.

1993-01-01

This paper addresses the issue of obtaining bounds on the real parameter perturbations of a linear state-space model for robust stability. Based on Kronecker algebra, new, easily computable sufficient bounds are derived that are much less conservative than the existing bounds since the technique is meant for only real parameter perturbations (in contrast to specializing complex variation case to real parameter case). The proposed theory is illustrated with application to several flight control examples.

Adaptive integral feedback controller for pitch and yaw channels of an AUV with actuator saturations.

PubMed

Sarhadi, Pouria; Noei, Abolfazl Ranjbar; Khosravi, Alireza

2016-11-01

Input saturations and uncertain dynamics are among the practical challenges in control of autonomous vehicles. Adaptive control is known as a proper method to deal with the uncertain dynamics of these systems. Therefore, incorporating the ability to confront with input saturation in adaptive controllers can be valuable. In this paper, an adaptive autopilot is presented for the pitch and yaw channels of an autonomous underwater vehicle (AUV) in the presence of input saturations. This will be performed by combination of a model reference adaptive control (MRAC) with integral state feedback with a modern anti-windup (AW) compensator. MRAC with integral state feedback is commonly used in autonomous vehicles. However, some proper modifications need to be taken into account in order to cope with the saturation problem. To this end, a Riccati-based anti-windup (AW) compensator is employed. The presented technique is applied to the non-linear six degrees of freedom (DOF) model of an AUV and the obtained results are compared with that of its baseline method. Several simulation scenarios are executed in the pitch and yaw channels to evaluate the controller performance. Moreover, effectiveness of proposed adaptive controller is comprehensively investigated by implementing Monte Carlo simulations. The obtained results verify the performance of proposed method. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive suboptimal second-order sliding mode control for microgrids

NASA Astrophysics Data System (ADS)

Incremona, Gian Paolo; Cucuzzella, Michele; Ferrara, Antonella

2016-09-01

This paper deals with the design of adaptive suboptimal second-order sliding mode (ASSOSM) control laws for grid-connected microgrids. Due to the presence of the inverter, of unpredicted load changes, of switching among different renewable energy sources, and of electrical parameters variations, the microgrid model is usually affected by uncertain terms which are bounded, but with unknown upper bounds. To theoretically frame the control problem, the class of second-order systems in Brunovsky canonical form, characterised by the presence of matched uncertain terms with unknown bounds, is first considered. Four adaptive strategies are designed, analysed and compared to select the most effective ones to be applied to the microgrid case study. In the first two strategies, the control amplitude is continuously adjusted, so as to arrive at dominating the effect of the uncertainty on the controlled system. When a suitable control amplitude is attained, the origin of the state space of the auxiliary system becomes attractive. In the other two strategies, a suitable blend between two components, one mainly working during the reaching phase, the other being the predominant one in a vicinity of the sliding manifold, is generated, so as to reduce the control amplitude in steady state. The microgrid system in a grid-connected operation mode, controlled via the selected ASSOSM control strategies, exhibits appreciable stability properties, as proved theoretically and shown in simulation.

Seeing through the Smoke: A collaborative, multidisciplinary effort to address the interplay between wildfire, climate, air quality, and health

NASA Astrophysics Data System (ADS)

Brey, S. J.; Fischer, E. V.; Pierce, J. R.; Ford, B.; Lassman, W.; Pfister, G.; Volckens, J.; Gan, R.; Magzamen, S.; Barnes, E. A.

2015-12-01

Exposure to wildfire smoke plumes represents an episodic, uncertain, and potentially growing threat to public health in the western United States. The area burned by wildfires in this region has increased over recent decades, and the future of fires within this region is largely unknown. Future fire emissions are intimately linked to future meteorological conditions, which are uncertain due to the variability of climate model outputs and differences between representative concentration pathways (RCP) scenarios. We know that exposure to wildfire smoke is harmful, particularly for vulnerable populations. However the literature on the heath effects of wildfire smoke exposure is thin, particularly when compared to the depth of information we have on the effects of exposure to smoke of anthropogenic origin. We are exploring the relationships between climate, fires, air quality and public health through multiple interdisciplinary collaborations. We will present several examples from these projects including 1) an analysis of the influence of fire on ozone abundances over the United States, and 2) efforts to use a high-resolution weather forecasting model to nail down exposure within specific smoke plumes. We will also highlight how our team works together. This discussion will include examples of the university structure that facilitates our current collaborations, and the lessons we have learned by seeking stakeholder input to make our science more useful.

Robust synergetic control design under inputs and states constraints

NASA Astrophysics Data System (ADS)

Rastegar, Saeid; Araújo, Rui; Sadati, Jalil

2018-03-01

In this paper, a novel robust-constrained control methodology for discrete-time linear parameter-varying (DT-LPV) systems is proposed based on a synergetic control theory (SCT) approach. It is shown that in DT-LPV systems without uncertainty, and for any unmeasured bounded additive disturbance, the proposed controller accomplishes the goal of stabilising the system by asymptotically driving the error of the controlled variable to a bounded set containing the origin and then maintaining it there. Moreover, given an uncertain DT-LPV system jointly subject to unmeasured and constrained additive disturbances, and constraints in states, input commands and reference signals (set points), then invariant set theory is used to find an appropriate polyhedral robust invariant region in which the proposed control framework is guaranteed to robustly stabilise the closed-loop system. Furthermore, this is achieved even for the case of varying non-zero control set points in such uncertain DT-LPV systems. The controller is characterised to have a simple structure leading to an easy implementation, and a non-complex design process. The effectiveness of the proposed method and the implications of the controller design on feasibility and closed-loop performance are demonstrated through application examples on the temperature control on a continuous-stirred tank reactor plant, on the control of a real-coupled DC motor plant, and on an open-loop unstable system example.

Optimal Decision Making in a Class of Uncertain Systems Based on Uncertain Variables

NASA Astrophysics Data System (ADS)

Bubnicki, Z.

2006-06-01

The paper is concerned with a class of uncertain systems described by relational knowledge representations with unknown parameters which are assumed to be values of uncertain variables characterized by a user in the form of certainty distributions. The first part presents the basic optimization problem consisting in finding the decision maximizing the certainty index that the requirement given by a user is satisfied. The main part is devoted to the description of the optimization problem with the given certainty threshold. It is shown how the approach presented in the paper may be applied to some problems for anticipatory systems.

Uncertain sightings and the extinction of the Ivory-billed Woodpecker.

PubMed

Solow, Andrew; Smith, Woollcott; Burgman, Mark; Rout, Tracy; Wintle, Brendan; Roberts, David

2012-02-01

The extinction of a species can be inferred from a record of its sightings. Existing methods for doing so assume that all sightings in the record are valid. Often, however, there are sightings of uncertain validity. To date, uncertain sightings have been treated in an ad hoc way, either excluding them from the record or including them as if they were certain. We developed a Bayesian method that formally accounts for such uncertain sightings. The method assumes that valid and invalid sightings follow independent Poisson processes and use noninformative prior distributions for the rate of valid sightings and for a measure of the quality of uncertain sightings. We applied the method to a recently published record of sightings of the Ivory-billed Woodpecker (Campephilus principalis). This record covers the period 1897-2010 and contains 39 sightings classified as certain and 29 classified as uncertain. The Bayes factor in favor of extinction was 4.03, which constitutes substantial support for extinction. The posterior distribution of the time of extinction has 3 main modes in 1944, 1952, and 1988. The method can be applied to sighting records of other purportedly extinct species. ©2011 Society for Conservation Biology.

Pinatubo Emulation in Multiple Models (POEMs): co-ordinated experiments in the ISA-MIP model intercomparison activity component of the SPARC Stratospheric Sulphur and it's Role in Climate initiative (SSiRC)

NASA Astrophysics Data System (ADS)

Lee, Lindsay; Mann, Graham; Carslaw, Ken; Toohey, Matthew; Aquila, Valentina

2016-04-01

The World Climate Research Program's SPARC initiative has a new international activity "Stratospheric Sulphur and its Role in Climate" (SSiRC) to better understand changes in stratospheric aerosol and precursor gaseous sulphur species. One component of SSiRC involves an intercomparison "ISA-MIP" of composition-climate models that simulate the stratospheric aerosol layer interactively. Within PoEMS each modelling group will run a "perturbed physics ensemble" (PPE) of interactive stratospheric aerosol (ISA) simulations of the Pinatubo eruption, varying several uncertain parameters associated with the eruption's SO2 emissions and model processes. A powerful new technique to quantify and attribute sources of uncertainty in complex global models is described by Lee et al. (2011, ACP). The analysis uses Gaussian emulation to derive a probability density function (pdf) of predicted quantities, essentially interpolating the PPE results in multi-dimensional parameter space. Once trained on the ensemble, a Monte Carlo simulation with the fast Gaussian emulator enabling a full variance-based sensitivity analysis. The approach has already been used effectively by Carslaw et al., (2013, Nature) to quantify the uncertainty in the cloud albedo effect forcing from a 3D global aerosol-microphysics model allowing to compare the sensitivy of different predicted quantities to uncertainties in natural and anthropogenic emissions types, and structural parameters in the models. Within ISA-MIP, each group will carry out a PPE of runs, with the subsequent analysis with the emulator assessing the uncertainty in the volcanic forcings predicted by each model. In this poster presentation we will give an outline of the "PoEMS" analysis, describing the uncertain parameters to be varied and the relevance to further understanding differences identified in previous international stratospheric aerosol assessments.

The clinical significance of occult gynecologic primary tumours in metastatic cancer.

PubMed

Hannouf, M B; Winquist, E; Mahmud, S M; Brackstone, M; Sarma, S; Rodrigues, G; Rogan, P K; Hoch, J S; Zaric, G S

2017-10-01

We estimated the frequency of occult gynecologic primary tumours (gpts) in patients with metastatic cancer from an uncertain primary and evaluated the effect on disease management and overall survival (os). We used Manitoba administrative health databases to identify all patients initially diagnosed with metastatic cancer during 2002-2011. We defined patients as having an "occult" primary tumour if the primary was classified at least 6 months after the initial diagnosis. Otherwise, we considered patients to have "obvious" primaries. We then compared clinicopathologic and treatment characteristics and 2-year os for women with occult and with obvious gpts. We used Cox regression adjustment and propensity score methods to assess the effect on os of having an occult gpt. Among the 5953 patients diagnosed with metastatic cancer, occult primary tumours were more common in women ( n = 285 of 2552, 11.2%) than in men ( n = 244 of 3401, 7.2%). In women, gpts were the most frequent occult primary tumours ( n = 55 of 285, 19.3%). Compared with their counterparts having obvious gpts, women with occult gpts ( n = 55) presented with similar histologic and metastatic patterns but received fewer gynecologic diagnostic examinations during diagnostic work-up. Women with occult gpts were less likely to undergo surgery, waited longer for radiotherapy, and received a lesser variety of chemotherapeutic agents. Having an occult compared with an obvious gpt was associated with decreased os (hazard ratio: 1.62; 95% confidence interval: 1.2 to 2.35). Similar results were observed in adjusted analyses. In women with metastatic cancer from an uncertain primary, gpts constitute the largest clinical entity. Accurate diagnosis of occult gpts early in the course of metastatic cancer might lead to more effective treatment decisions and improved survival outcomes.

The clinical significance of occult gynecologic primary tumours in metastatic cancer

PubMed Central

Hannouf, M.B.; Winquist, E.; Mahmud, S.M.; Brackstone, M.; Sarma, S.; Rodrigues, G.; Rogan, P.K.; Hoch, J.S.; Zaric, G.S.

2017-01-01

Objective We estimated the frequency of occult gynecologic primary tumours (gpts) in patients with metastatic cancer from an uncertain primary and evaluated the effect on disease management and overall survival (os). Methods We used Manitoba administrative health databases to identify all patients initially diagnosed with metastatic cancer during 2002–2011. We defined patients as having an “occult” primary tumour if the primary was classified at least 6 months after the initial diagnosis. Otherwise, we considered patients to have “obvious” primaries. We then compared clinicopathologic and treatment characteristics and 2-year os for women with occult and with obvious gpts. We used Cox regression adjustment and propensity score methods to assess the effect on os of having an occult gpt. Results Among the 5953 patients diagnosed with metastatic cancer, occult primary tumours were more common in women (n = 285 of 2552, 11.2%) than in men (n = 244 of 3401, 7.2%). In women, gpts were the most frequent occult primary tumours (n = 55 of 285, 19.3%). Compared with their counterparts having obvious gpts, women with occult gpts (n = 55) presented with similar histologic and metastatic patterns but received fewer gynecologic diagnostic examinations during diagnostic work-up. Women with occult gpts were less likely to undergo surgery, waited longer for radiotherapy, and received a lesser variety of chemotherapeutic agents. Having an occult compared with an obvious gpt was associated with decreased os (hazard ratio: 1.62; 95% confidence interval: 1.2 to 2.35). Similar results were observed in adjusted analyses. Conclusions In women with metastatic cancer from an uncertain primary, gpts constitute the largest clinical entity. Accurate diagnosis of occult gpts early in the course of metastatic cancer might lead to more effective treatment decisions and improved survival outcomes. PMID:29089807

Eco-innovations in the functioning of companies.

PubMed

Ociepa-Kubicka, A; Pachura, P

2017-07-01

The development of entrepreneurships in the 21st century cannot occur without taking care of the natural environment. The article presents issues related to eco-innovation. Despite the opportunities offered by eco-innovations, implementation of such initiatives remains to lead to various difficulties. They vary across countries and sectors. The insufficient number of enterprises in Poland and other European countries implement adequate level of eco-innovations. The main aim of this paper is to indicate the causes of this status and activities aimed to develop eco-innovativeness. The benefits and risks connected with implementation of innovative products and technologies were also discussed. Furthermore, the advantages of and barriers to their implementation into companies were analysed. The entrepreneurs from the least eco-innovative countries emphasize serious barriers, including uncertain demand from the market, uncertain return on investment or too long a payback period for eco-innovation, lack of funds within the enterprise, insufficient access to existing subsidies and fiscal incentive. They are especially afraid of the financial risks, which raises uncertainty and leads to refraining from innovative initiatives. The possibilities were indicated for the entrepreneurs who face problems with the implementation of innovative solutions. Particular attention was paid to the European Union activities for the development of eco-innovations. Numerous programs supporting their implementation were indicated. The article also presents examples of eco-innovation in water and sewage enterprises. It was emphasized that planning of eco-innovative solutions should be based on comprehensive information about actual benefits and possibility of threats to the environment which can be caused by implementation of eco-innovations. The study presents the example of threats resulting from different methods of sewage sludge management. Copyright © 2017 Elsevier Inc. All rights reserved.

Cooperative path planning for multi-USV based on improved artificial bee colony algorithm

NASA Astrophysics Data System (ADS)

Cao, Lu; Chen, Qiwei

2018-03-01

Due to the complex constraints, more uncertain factors and critical real-time demand of path planning for multiple unmanned surface vehicle (multi-USV), an improved artificial bee colony (I-ABC) algorithm were proposed to solve the model of cooperative path planning for multi-USV. First the Voronoi diagram of battle field space is conceived to generate the optimal area of USVs paths. Then the chaotic searching algorithm is used to initialize the collection of paths, which is regard as foods of the ABC algorithm. With the limited data, the initial collection can search the optimal area of paths perfectly. Finally simulations of the multi-USV path planning under various threats have been carried out. Simulation results verify that the I-ABC algorithm can improve the diversity of nectar source and the convergence rate of algorithm. It can increase the adaptability of dynamic battlefield and unexpected threats for USV.

Infection rate of Leptospira interrogans in the field rodent, Apodemus agrarius, in Korea.

PubMed Central

Cho, M. K.; Kee, S. H.; Song, H. J.; Kim, K. H.; Song, K. J.; Baek, L. J.; Kim, H. H.; Oh, H. B.; Kim, Y. W.; Chang, W. H.

1998-01-01

Leptospirosis has significantly decreased in Korea since 1988, following the leptospiral vaccination programme initiated in 1988. Whether this wholly explains the decreased incidence is uncertain. As an initial step to answer this question, infection rates of Leptospira interrogans in field rodents, Apodemis agrarius, were examined and compared with previous data. Two hundred and twenty-two A. agrarius were captured during October-December 1996. Spirochaetes were isolated from 22 (9.9%) and leptospiral DNA was detected in an additional 6 rodents (12.6%). Subsequent microscopic agglutination tests (MAT) classified all these isolates as L. interrogans serogroup Icterohaemorrhagiae serovar lai. The above data did not significantly differ from previous surveys in 1984-7. There was no significant change of L. interrogans infection in field rodents following the introduction of the vaccination programme in Korea. Further studies are needed to determine the role of human vaccination in reducing incidence. PMID:10030719

Marital crises in oncology patients. An approach to initial intervention by primary clinicians.

PubMed

Peteet, J; Greenberg, B

1995-05-01

Life-threatening illnesses such as cancer may precipitate marital crises in vulnerable relationships, and oncology clinicians often feel uncertain about how to approach them. This paper presents a framework for initial intervention based on the nature of the principal threat to the relationship. Immature relationships need distance and support for their identity as a couple; hostile dependent couples need to find consensus in order to structure communication; physically abusive relationships require monitoring in order to promote safety; and estranged couples need help in understanding their disappointment and identifying available support. Clinicians working in oncology can help couples in crisis by promoting a realistic balance of independence and dependence, clarifying the complexity of factors contributing to the crisis, considering referral for couples treatment, communicating with the team while respecting patients' confidences, and by choosing clear and compatible clinical roles. Primary clinicians can stabilize and treat marital crises, but need access to medically knowledgeable couples' therapists.

A new look at the Y tetraquarks and Ω _c baryons in the diquark model

NASA Astrophysics Data System (ADS)

Ali, Ahmed; Maiani, Luciano; Borisov, Anatoly V.; Ahmed, Ishtiaq; Aslam, M. Jamil; Parkhomenko, Alexander Ya.; Polosa, Antonio D.; Rehman, Abdur

2018-01-01

We analyze the hidden charm P-wave tetraquarks in the diquark model, using an effective Hamiltonian incorporating the dominant spin-spin, spin-orbit and tensor interactions. We compare with other P-wave systems such as P-wave charmonia and the newly discovered Ω _c baryons, analysed recently in this framework. Given the uncertain experimental situation on the Y states, we allow for different spectra and discuss the related parameters in the diquark model. In addition to the presently observed ones, we expect many more states in the supermultiplet of L=1 diquarkonia, whose J^{PC} quantum numbers and masses are worked out, using the parameters from the currently preferred Y-states pattern. The existence of these new resonances would be a decisive footprint of the underlying diquark dynamics.

Retrospective economic evaluation of childhood 7-valent pneumococcal conjugate vaccination in Australia: Uncertain herd impact on pneumonia critical.

PubMed

Newall, A T; Reyes, J F; McIntyre, P; Menzies, R; Beutels, P; Wood, J G

2016-01-12

Retrospective cost-effectiveness analyses of vaccination programs using routinely collected post-implementation data are sparse by comparison with pre-program analyses. We performed a retrospective economic evaluation of the childhood 7-valent pneumococcal conjugate vaccine (PCV7) program in Australia. We developed a deterministic multi-compartment model that describes health states related to invasive and non-invasive pneumococcal disease. Costs (Australian dollars, A$) and health effects (quality-adjusted life years, QALYs) were attached to model states. The perspective for costs was that of the healthcare system and government. Where possible, we used observed changes in the disease rates from national surveillance and healthcare databases to estimate the impact of the PCV7 program (2005-2010). We stratified our cost-effectiveness results into alternative scenarios which differed by the outcome states included. Parameter uncertainty was explored using probabilistic sensitivity analysis. The PCV7 program was estimated to have prevented ∼5900 hospitalisations and ∼160 deaths from invasive pneumococcal disease (IPD). Approximately half of these were prevented in adults via herd protection. The incremental cost-effectiveness ratio was ∼A$161,000 per QALY gained when including only IPD-related outcomes. The cost-effectiveness of PCV7 remained in the range A$88,000-$122,000 when changes in various non-invasive disease states were included. The inclusion of observed changes in adult non-invasive pneumonia deaths substantially improved cost-effectiveness (∼A$9000 per QALY gained). Using the initial vaccine price negotiated for Australia, the PCV7 program was unlikely to have been cost-effective (at conventional thresholds) unless observed reductions in non-invasive pneumonia deaths in the elderly are attributed to it. Further analyses are required to explore this finding, which has significant implications for the incremental benefit achievable by adult PCV programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Adjoint Force-restore Model for Glacier Terminus Fluctuations

NASA Astrophysics Data System (ADS)

Ren, D.; Leslie, L.; Karoly, D.

2006-12-01

A linear inverse formula comprises the basis for an individual treatment of 7 central Asian (25-55°N; 70-95°E) glaciers. The linear forward model is based on first order glacier dynamics, and requires the knowledge of reference states of forcing and glacier perturbation magnitude. In this study, the adjoint based 4D-var method was applied to optimally determine the reference states and make it possible to start the integration at an arbitrarily chosen time, and thus suitable to use the availability of the coupled general circulation model (CGCM) predictions of future temperature scenarios. Two sensitive yet uncertain glacier parameters and reference states at year 1900 are inferred from observed glacier length records distributed irregularly over the 20th century and the regional mean annual temperature anomaly (against 1961-1990 reference) time series. We rotated the temperature forcing for the Hadley Centre- Climatic Research Unit of the University of East Anglia (HadCRUT2), the Global Historical Climatology Network (GHCN) observations, and the ensemble mean of multiple CGCM runs and compared the retrieval results. Because of the high resemblance between the three data sources after 1960, it was decided practicable to use the observed temperature as forcing in retrieving the model parameters and initial states and then run an extended period with forcing from ensemble mean CGCM temperature of the next century. The length fluctuation is estimated for the transient climate period with 9 CGCM simulations under SRES A2 (a strong emission scenario from the Special report on Emissions Scenarios). For the 60-year period 2000- 2060, all glaciers experienced salient shrinkage, especially those with gentle slopes. Although nearly one-third the year 2000 length will be reduced for some small glaciers, the very existence of the glaciers studied here is not threatened by year 2060. The differences in individual glacier responses are very large. No straightforward relationship is found between glacier size and fractional change of its length.

Making the case for OWTS management: lessons from case studies and research

NASA Astrophysics Data System (ADS)

Rahm, B.; Woods, F.; Hwang, S.; Walter, M. T.; Grantham, D. G.; Riha, S. J.

2016-12-01

On-site wastewater treatment systems (OWTS) are used in 20-25% of homes in the United States and can be an efficient and cost-effective alternative to conventional centralized systems. However, OWTS also represent a source of non-point nutrient, pathogen, and micro-contaminant pollution to surface and groundwater if they are poorly designed, sited and/or maintained. Despite their ubiquity and potential to negatively impact water resources, the contribution of OWTS to local and regional water contamination issues is poorly understood. There are no federal regulations or uniform standards for the operation, maintenance, and management of these systems. The effectiveness of educational programs and best management practices developed by the US Environmental Protection Agency, along with local and regional governments, remains uncertain. Here we describe attempts to increase our knowledge of the state of OWTS in relation to water resources and their management. Specifically, we summarize 1) efforts to modernize a NY State-wide inventory of residential OWTS using GIS-based tools; 2) research aimed at better understanding the impact of OWTS on surface and ground water in 5 upstate NY counties across a gradient of land uses; 3) lessons learned from 13 case studies of municipal OWTS management programs across the US; and 4) observations on the roles of data, education and policy in creating and evaluating successful municipal OWTS management programs. Initial results show that total numbers of OWTS in NY State continue to grow, particularly in areas associated with ex-urban migration. Research into the relationship between OWTS and nutrient and pathogen contamination in ground and surface waters, respectively, suggests location-specific variation. This has implications for management approaches: preventing failure of any individual OWTS may be just as effective as programs attempting to bring all OWTS up to a high level of performance. Case studies of management programs, which we assess using a set of policy-related criteria, suggest that approaches differ according to local regulations, stakeholder values, and other environmental, economic, and social factors.

Set-theoretic estimation of hybrid system configurations.

PubMed

Benazera, Emmanuel; Travé-Massuyès, Louise

2009-10-01

Hybrid systems serve as a powerful modeling paradigm for representing complex continuous controlled systems that exhibit discrete switches in their dynamics. The system and the models of the system are nondeterministic due to operation in uncertain environment. Bayesian belief update approaches to stochastic hybrid system state estimation face a blow up in the number of state estimates. Therefore, most popular techniques try to maintain an approximation of the true belief state by either sampling or maintaining a limited number of trajectories. These limitations can be avoided by using bounded intervals to represent the state uncertainty. This alternative leads to splitting the continuous state space into a finite set of possibly overlapping geometrical regions that together with the system modes form configurations of the hybrid system. As a consequence, the true system state can be captured by a finite number of hybrid configurations. A set of dedicated algorithms that can efficiently compute these configurations is detailed. Results are presented on two systems of the hybrid system literature.

Considerations and challenges in defining optimal iron utilization in hemodialysis.

PubMed

Charytan, David M; Pai, Amy Barton; Chan, Christopher T; Coyne, Daniel W; Hung, Adriana M; Kovesdy, Csaba P; Fishbane, Steven

2015-06-01

Trials raising concerns about erythropoiesis-stimulating agents, revisions to their labeling, and changes to practice guidelines and dialysis payment systems have provided strong stimuli to decrease erythropoiesis-stimulating agent use and increase intravenous iron administration in recent years. These factors have been associated with a rise in iron utilization, particularly among hemodialysis patients, and an unprecedented increase in serum ferritin concentrations. The mean serum ferritin concentration among United States dialysis patients in 2013 exceeded 800 ng/ml, with 18% of patients exceeding 1200 ng/ml. Although these changes are broad based, the wisdom of these practices is uncertain. Herein, we examine influences on and trends in intravenous iron utilization and assess the clinical trial, epidemiologic, and experimental evidence relevant to its safety and efficacy in the setting of maintenance dialysis. These data suggest a potential for harm from increasing use of parenteral iron in dialysis-dependent patients. In the absence of well powered, randomized clinical trials, available evidence will remain inadequate for making reliable conclusions about the effect of a ubiquitous therapy on mortality or other outcomes of importance to dialysis patients. Nephrology stakeholders have an urgent obligation to initiate well designed investigations of intravenous iron in order to ensure the safety of the dialysis population. Copyright © 2015 by the American Society of Nephrology.

Competition for water vapour results in suppression of ice formation in mixed-phase clouds

NASA Astrophysics Data System (ADS)

Simpson, Emma L.; Connolly, Paul J.; McFiggans, Gordon

2018-05-01

The formation of ice in clouds can initiate precipitation and influence a cloud's reflectivity and lifetime, affecting climate to a highly uncertain degree. Nucleation of ice at elevated temperatures requires an ice nucleating particle (INP), which results in so-called heterogeneous freezing. Previously reported measurements for the ability of a particle to nucleate ice have been made in the absence of other aerosol which will act as cloud condensation nuclei (CCN) and are ubiquitous in the atmosphere. Here we show that CCN can outcompete INPs for available water vapour thus suppressing ice formation, which has the potential to significantly affect the Earth's radiation budget. The magnitude of this suppression is shown to be dependent on the mass of condensed water required for freezing. Here we show that ice formation in a state-of-the-art cloud parcel model is strongly dependent on the criteria for heterogeneous freezing selected from those previously hypothesised. We have developed an alternative criteria which agrees well with observations from cloud chamber experiments. This study demonstrates the dominant role that competition for water vapour can play in ice formation, highlighting both a need for clarity in the requirements for heterogeneous freezing and for measurements under atmospherically appropriate conditions.

Developing and applying metamodels of high resolution ...

EPA Pesticide Factsheets

As defined by Wikipedia (https://en.wikipedia.org/wiki/Metamodeling), “(a) metamodel or surrogate model is a model of a model, and metamodeling is the process of generating such metamodels.” The goals of metamodeling include, but are not limited to (1) developing functional or statistical relationships between a model’s input and output variables for model analysis, interpretation, or information consumption by users’ clients; (2) quantifying a model’s sensitivity to alternative or uncertain forcing functions, initial conditions, or parameters; and (3) characterizing the model’s response or state space. Using five existing models developed by US Environmental Protection Agency, we generate a metamodeling database of the expected environmental and biological concentrations of 644 organic chemicals released into nine US rivers from wastewater treatment works (WTWs) assuming multiple loading rates and sizes of populations serviced. The chemicals of interest have log n-octanol/water partition coefficients ( ) ranging from 3 to 14, and the rivers of concern have mean annual discharges ranging from 1.09 to 3240 m3/s. Log linear regression models are derived to predict mean annual dissolved and total water concentrations and total sediment concentrations of chemicals of concern based on their , Henry’s Law Constant, and WTW loading rate and on the mean annual discharges of the receiving rivers. Metamodels are also derived to predict mean annual chemical

Adaptive nonsingular fast terminal sliding-mode control for the tracking problem of uncertain dynamical systems.

PubMed

Boukattaya, Mohamed; Mezghani, Neila; Damak, Tarak

2018-06-01

In this paper, robust and adaptive nonsingular fast terminal sliding-mode (NFTSM) control schemes for the trajectory tracking problem are proposed with known or unknown upper bound of the system uncertainty and external disturbances. The developed controllers take the advantage of the NFTSM theory to ensure fast convergence rate, singularity avoidance, and robustness against uncertainties and external disturbances. First, a robust NFTSM controller is proposed which guarantees that sliding surface and equilibrium point can be reached in a short finite-time from any initial state. Then, in order to cope with the unknown upper bound of the system uncertainty which may be occurring in practical applications, a new adaptive NFTSM algorithm is developed. One feature of the proposed control law is their adaptation techniques where the prior knowledge of parameters uncertainty and disturbances is not needed. However, the adaptive tuning law can estimate the upper bound of these uncertainties using only position and velocity measurements. Moreover, the proposed controller eliminates the chattering effect without losing the robustness property and the precision. Stability analysis is performed using the Lyapunov stability theory, and simulation studies are conducted to verify the effectiveness of the developed control schemes. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Parental monitoring at age 11 and smoking initiation up to age 17 among Blacks and Whites: a prospective investigation.

PubMed

Bohnert, Kipling M; Ríos-Bedoya, Carlos F; Breslau, Naomi

2009-12-01

Parental monitoring has been identified as a predictor of adolescent smoking initiation. However, it is uncertain if the association is uniform across different racial groups. Random samples of low birth-weight and normal birth-weight children were drawn from newborn discharge lists (1983-1985) of two major hospitals in southeast Michigan, one serving an inner city and the other serving suburbs. Assessments occurred at ages 6, 11, and 17 years. Statistical analysis was conducted on children with data on parent monitoring at age 11 and tobacco use at age 17 who had never smoked a cigarette up to age 11 (n = 572). Multiple logistic regression was used to examine the association between parent monitoring and children's smoking initiation. Two-way interactions were tested. The relationship between parent monitoring at age 11 and child smoking initiation from ages 11 to 17 varied by race. Among White children, an increase of 1 point on the parent monitoring scale signaled an 11% reduction in the odds of initiating smoking by age 17. In contrast, parent monitoring was not significantly associated with smoking initiation among Black children. The results suggest a differential influence of parent monitoring on adolescent smoking between White and Black children. Future research would benefit from close attention to parental goals and concerns and to extra-familial factors that shape smoking behavior across racially and socially disparate communities.

Equilibrium sensitivities of the Greenland ice sheet inferred from the adjoint of the three- dimensional thermo-mechanical model SICOPOLIS

NASA Astrophysics Data System (ADS)

Heimbach, P.; Bugnion, V.

2008-12-01

We present a new and original approach to understanding the sensitivity of the Greenland ice sheet to key model parameters and environmental conditions. At the heart of this approach is the use of an adjoint ice sheet model. MacAyeal (1992) introduced adjoints in the context of applying control theory to estimate basal sliding parameters (basal shear stress, basal friction) of an ice stream model which minimize a least-squares model vs. observation misfit. Since then, this method has become widespread to fit ice stream models to the increasing number and diversity of satellite observations, and to estimate uncertain model parameters. However, no attempt has been made to extend this method to comprehensive ice sheet models. Here, we present a first step toward moving beyond limiting the use of control theory to ice stream models. We have generated an adjoint of the three-dimensional thermo-mechanical ice sheet model SICOPOLIS of Greve (1997). The adjoint was generated using the automatic differentiation (AD) tool TAF. TAF generates exact source code representing the tangent linear and adjoint model of the parent model provided. Model sensitivities are given by the partial derivatives of a scalar-valued model diagnostic or "cost function" with respect to the controls, and can be efficiently calculated via the adjoint. An effort to generate an efficient adjoint with the newly developed open-source AD tool OpenAD is also under way. To gain insight into the adjoint solutions, we explore various cost functions, such as local and domain-integrated ice temperature, total ice volume or the velocity of ice at the margins of the ice sheet. Elements of our control space include initial cold ice temperatures, surface mass balance, as well as parameters such as appear in Glen's flow law, or in the surface degree-day or basal sliding parameterizations. Sensitivity maps provide a comprehensive view, and allow a quantification of where and to which variables the ice sheet model is most sensitive to. The model used in the present study includes simplifications in the model physics, parameterizations which rely on uncertain empirical constants, and is unable to capture fast ice streams. Nevertheless, as a proof-of-concept, this method can readily be extended to incorporate higher-order physics or parameterizations (or be applied to other models). It also opens the door to ice sheet state estimation: using the model's physics jointly with field and satellite observations to estimate a best estimate of the state of the ice sheets.

Coupled hydrological and geochemical process evolution at the Landscape Evolution Observatory

NASA Astrophysics Data System (ADS)

Troch, P. A. A.

2015-12-01

Predictions of hydrologic and biogeochemical responses to natural and anthropogenic forcing at the landscape scale are highly uncertain due to the effects of heterogeneity on the scaling of reaction, flow and transport phenomena. The physical, chemical and biological structures and processes controlling reaction, flow and transport in natural landscapes interact at multiple space and time scales and are difficult to quantify. The current paradigm of hydrological and geochemical theory is that process descriptions derived from observations at small scales in controlled systems can be applied to predict system response at much larger scales, as long as some 'equivalent' or 'effective' values of the scale-dependent parameters can be identified. Furthermore, natural systems evolve in time in a way that is hard to observe in short-run laboratory experiments or in natural landscapes with unknown initial conditions and time-variant forcing. The spatial structure of flow pathways along hillslopes determines the rate, extent and distribution of geochemical reactions (and biological colonization) that drive weathering, the transport and precipitation of solutes and sediments, and the further evolution of soil structure. The resulting evolution of structures and processes, in turn, produces spatiotemporal variability of hydrological states and flow pathways. There is thus a need for experimental research to improve our understanding of hydrology-biogeochemistry interactions and feedbacks at appropriate spatial scales larger than laboratory soil column experiments. Such research is complicated in real-world settings because of poorly constrained impacts of initial conditions, climate variability, ecosystems dynamics, and geomorphic evolution. The Landscape Evolution Observatory (LEO) at Biosphere 2 offers a unique research facility that allows real-time observations of incipient hydrologic and biogeochemical response under well-constrained initial conditions and climate forcing. The LEO allows to close the water, carbon and energy budgets at hillslope scales, thereby enabling elucidation of the tight coupling between the time water spends along subsurface flow paths and geochemical weathering reactions, including the feedbacks between flow and pedogenesis.

Megacities and the United States Army: Preparing for a Complex and Uncertain Future

DTIC Science & Technology

2014-06-01

NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Office of the Chief of Staff of the Army,Strategic...problems found in megacities (explosive growth rates, vast and growing income disparity and a security envi- ronment that is increasingly attractive to the ...that growth oc- curring almost entirely in developing world. 5 As re- sources become constrained, illicit networks could po- tentially fill the gap left

The Growing Nexus: Energy, Environmental Causes and Sovereignty

DTIC Science & Technology

2012-03-22

unalienable human rights, the world’s best and most advanced health care , an exemplary free enterprise business foundation, and a proactive approach towards...stated that he’s an agnostic on the science of global warming. “I don’t know if the CO2 zealots are right, but I don’t care , because we simply cannot...the DOE propagates politically correct pet projects at the expense of the American people.97 35 The Way Ahead Today’s volatile and uncertain

Estrellas Be en cúmulos abiertos

NASA Astrophysics Data System (ADS)

Aidelman, Y. J.; Cidale, L. S.; Zorec, J.

Be stars are non-supergiant B-type stars which show or have shown once the line H in emission. This emission is attributed to the formation of a circumstellar envelope. The evolutionary state of the Be stars still is a big question because the phase in which the disk formation process takes place is uncertain. To address this problem; we have begun a study of Be stars in galactic open clusters. In this paper we show some preliminary results. FULL TEXT IN SPANISH

The Coast Artillery Journal. Volume 60, Number 1, January 1924

DTIC Science & Technology

1924-01-01

mainmast toppled just befol’e the ship turned turtle . Of the total of twenty-four 600 lb. bombs which were dropped from 10.000 feet, seventeen functioned...eighteen minutes after being ,truck, the rirg;lIia turned turtle to port and began to settle. The (’onfined air burst the sealllS along her keel. At 12 :2...generally as- sumed, not stated, and is for that reason nebulous and uncertain. 2. Economy of force--concentration of effectives, avoidance of dissemination

Setting the Context: Suppression of Enemy Air Defenses and Joint War Fighting in an Uncertain World

DTIC Science & Technology

1994-06-01

indicate, ironically, that the greatest suppression element the Wild Weasel possessed was psychological .9 As much as 95 percent of its effectiveness may...extravagant spending on the latest Soviet LAD systems-made them invulnerable to attack by the Americans, or a belief that the United States was bluffing . What...ARMS may have on the enemy that outweigh system Pk (i.e ., psychological warfare against enemy site operators via intimidation). Methods ofAnalysis In

Soviet Policy in the Post-Tito Balkans. Volume 4. Studies in Communist Affairs

DTIC Science & Technology

1979-01-01

with the West-was pioneered by these two communist states. The 1948 split with the Soviets forced President Tito and the Yugoslav leadership to search...power factor itself, the military strategist must be con- cerned with the geography and demography of the area in which he is to meet his opponent. In...day Yugoslavia as well as from their political longevity . Bakaric and Kardelj are in uncertain health; in Tito’s case, age alone constitutes a hazard

U.S. Policy and the Uncertain State of Military Usage of Riot Control Agents.

DTIC Science & Technology

1998-04-30

capsicum, a naturally occurring oily resin found in the cayenne pepper . Known as pepper spray or OC, it is different from CS, 23 CN, and other RCA...Non-Lethals 7 Riot Control Agents 11 The U.S. Army and CS 13 The RCA Policy Debate: Seventy Years of Uncertainty 15 Non-Chemical Pepper Spray: A...of the crowd to use their recently-issued pepper spray, but two soldiers were quickly injured by flying debris. The mob seemed

The Cramér-Rao Bounds and Sensor Selection for Nonlinear Systems with Uncertain Observations.

PubMed

Wang, Zhiguo; Shen, Xiaojing; Wang, Ping; Zhu, Yunmin

2018-04-05

This paper considers the problems of the posterior Cramér-Rao bound and sensor selection for multi-sensor nonlinear systems with uncertain observations. In order to effectively overcome the difficulties caused by uncertainty, we investigate two methods to derive the posterior Cramér-Rao bound. The first method is based on the recursive formula of the Cramér-Rao bound and the Gaussian mixture model. Nevertheless, it needs to compute a complex integral based on the joint probability density function of the sensor measurements and the target state. The computation burden of this method is relatively high, especially in large sensor networks. Inspired by the idea of the expectation maximization algorithm, the second method is to introduce some 0-1 latent variables to deal with the Gaussian mixture model. Since the regular condition of the posterior Cramér-Rao bound is unsatisfied for the discrete uncertain system, we use some continuous variables to approximate the discrete latent variables. Then, a new Cramér-Rao bound can be achieved by a limiting process of the Cramér-Rao bound of the continuous system. It avoids the complex integral, which can reduce the computation burden. Based on the new posterior Cramér-Rao bound, the optimal solution of the sensor selection problem can be derived analytically. Thus, it can be used to deal with the sensor selection of a large-scale sensor networks. Two typical numerical examples verify the effectiveness of the proposed methods.

Integrated Personal Health Records: Transformative Tools for Consumer-Centric Care

PubMed Central

Detmer, Don; Bloomrosen, Meryl; Raymond, Brian; Tang, Paul

2008-01-01

Background Integrated personal health records (PHRs) offer significant potential to stimulate transformational changes in health care delivery and self-care by patients. In 2006, an invitational roundtable sponsored by Kaiser Permanente Institute, the American Medical Informatics Association, and the Agency for Healthcare Research and Quality was held to identify the transformative potential of PHRs, as well as barriers to realizing this potential and a framework for action to move them closer to the health care mainstream. This paper highlights and builds on the insights shared during the roundtable. Discussion While there is a spectrum of dominant PHR models, (standalone, tethered, integrated), the authors state that only the integrated model has true transformative potential to strengthen consumers' ability to manage their own health care. Integrated PHRs improve the quality, completeness, depth, and accessibility of health information provided by patients; enable facile communication between patients and providers; provide access to health knowledge for patients; ensure portability of medical records and other personal health information; and incorporate auto-population of content. Numerous factors impede widespread adoption of integrated PHRs: obstacles in the health care system/culture; issues of consumer confidence and trust; lack of technical standards for interoperability; lack of HIT infrastructure; the digital divide; uncertain value realization/ROI; and uncertain market demand. Recent efforts have led to progress on standards for integrated PHRs, and government agencies and private companies are offering different models to consumers, but substantial obstacles remain to be addressed. Immediate steps to advance integrated PHRs should include sharing existing knowledge and expanding knowledge about them, building on existing efforts, and continuing dialogue among public and private sector stakeholders. Summary Integrated PHRs promote active, ongoing patient collaboration in care delivery and decision making. With some exceptions, however, the integrated PHR model is still a theoretical framework for consumer-centric health care. The authors pose questions that need to be answered so that the field can move forward to realize the potential of integrated PHRs. How can integrated PHRs be moved from concept to practical application? Would a coordinating body expedite this progress? How can existing initiatives and policy levers serve as catalysts to advance integrated PHRs? PMID:18837999

Weight bearing cone beam CT scan versus gravity stress radiography for analysis of supination external rotation injuries of the ankle.

PubMed

Marzo, John M; Kluczynski, Melissa A; Clyde, Corey; Anders, Mark J; Mutty, Christopher E; Ritter, Christopher A

2017-12-01

For AO 44-B2 ankle fractures of uncertain stability, the current diagnostic standard is to obtain a gravity stress radiograph, but some have advocated for the use of weight-bearing radiographs. The primary aim was to compare measures of medial clear space (MCS) on weight-bearing cone beam computed tomography (CBCT) scans versus gravity stress radiographs for determining the state of stability of ankle fractures classified as AO SER 44-B2 or Weber B. The secondary aim was to evaluate the details offered by CBCT scans with respect to other findings that may be relevant to patient care. Nine patients were enrolled in this cross-sectional study between April 2016 and February 2017 if they had an AO SER 44-B2 fracture of uncertain stability, had a gravity stress radiograph, and were able to undergo CT scan within seven days. The width of the MCS was measured at the level of the talar dome on all radiographs and at the mid coronal slice on CT. Wilcoxon signed-ranks tests were used to compare MCS between initial radiographs, gravity stress radiographs and weight-bearing CBCT scans. MCS on weight-bearing CBCT scan (1.41±0.41 mm) was significantly less than standard radiographs (3.28±1.63 mm, P=0.004) and gravity stress radiographs (5.82±1.93 mm, P=0.02). There was no statistically significant difference in MCS measured on standard radiographs versus gravity stress radiographs (P=0.11). Detailed review of the multiplanar CT images revealed less than perfect anatomical reduction of the fractures, with residual fibular shortening, posterior displacement, and fracture fragments in the incisura as typical findings. Similar to weight-bearing radiographs, weight-bearing CBCT scan can predict stability of AO 44-B2 ankle fractures by showing restoration of the MCS, and might be used to indicate patients for non-operative treatment. None of the fractures imaged in this study were perfectly reduced however, and further clinical research is necessary to determine if any of the detailed weight-bearing CBCT findings are related to patient outcomes.

A methodology for stochastic analysis of share prices as Markov chains with finite states.

PubMed

Mettle, Felix Okoe; Quaye, Enoch Nii Boi; Laryea, Ravenhill Adjetey

2014-01-01

Price volatilities make stock investments risky, leaving investors in critical position when uncertain decision is made. To improve investor evaluation confidence on exchange markets, while not using time series methodology, we specify equity price change as a stochastic process assumed to possess Markov dependency with respective state transition probabilities matrices following the identified state pace (i.e. decrease, stable or increase). We established that identified states communicate, and that the chains are aperiodic and ergodic thus possessing limiting distributions. We developed a methodology for determining expected mean return time for stock price increases and also establish criteria for improving investment decision based on highest transition probabilities, lowest mean return time and highest limiting distributions. We further developed an R algorithm for running the methodology introduced. The established methodology is applied to selected equities from Ghana Stock Exchange weekly trading data.

Robust adaptive controller design for a class of uncertain nonlinear systems using online T-S fuzzy-neural modeling approach.

PubMed

Chien, Yi-Hsing; Wang, Wei-Yen; Leu, Yih-Guang; Lee, Tsu-Tian

2011-04-01

This paper proposes a novel method of online modeling and control via the Takagi-Sugeno (T-S) fuzzy-neural model for a class of uncertain nonlinear systems with some kinds of outputs. Although studies about adaptive T-S fuzzy-neural controllers have been made on some nonaffine nonlinear systems, little is known about the more complicated uncertain nonlinear systems. Because the nonlinear functions of the systems are uncertain, traditional T-S fuzzy control methods can model and control them only with great difficulty, if at all. Instead of modeling these uncertain functions directly, we propose that a T-S fuzzy-neural model approximates a so-called virtual linearized system (VLS) of the system, which includes modeling errors and external disturbances. We also propose an online identification algorithm for the VLS and put significant emphasis on robust tracking controller design using an adaptive scheme for the uncertain systems. Moreover, the stability of the closed-loop systems is proven by using strictly positive real Lyapunov theory. The proposed overall scheme guarantees that the outputs of the closed-loop systems asymptotically track the desired output trajectories. To illustrate the effectiveness and applicability of the proposed method, simulation results are given in this paper.

Adaptive Control Allocation in the Presence of Actuator Failures

NASA Technical Reports Server (NTRS)

Liu, Yu; Crespo, Luis G.

2010-01-01

In this paper, a novel adaptive control allocation framework is proposed. In the adaptive control allocation structure, cooperative actuators are grouped and treated as an equivalent control effector. A state feedback adaptive control signal is designed for the equivalent effector and allocated to the member actuators adaptively. Two adaptive control allocation algorithms are proposed, which guarantee closed-loop stability and asymptotic state tracking in the presence of uncertain loss of effectiveness and constant-magnitude actuator failures. The proposed algorithms can be shown to reduce the controller complexity with proper grouping of the actuators. The proposed adaptive control allocation schemes are applied to two linearized aircraft models, and the simulation results demonstrate the performance of the proposed algorithms.

Chronic inflammatory demyelinating polyneuropathy-like neuropathy as an initial presentation of Crohn's disease.

PubMed

Kim, Suji; Kang, Seok-Jae; Oh, Ki-Wook; Ahn, Byung Kyu; Lee, Hang Lak; Han, Dong Soo; Jang, Kiseok; Kim, Young Seo

2015-03-28

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare complication of Crohn's disease (CD), and it is uncertain whether it is associated with CD itself or with its treatment. We describe a case of CIDP-like neuropathy as an initial symptom of CD. The neurologic symptoms of the patient which responded partially to intravenous immunoglobulin (IVIG) recovered after resection of the appendiceal CD. A 17-year-old male had experienced three separate attacks of motor weakness and paresthesia of all four extremities over a period of 7 months. The electrophysiologic findings revealed a demyelinating sensory-motor polyneuropathy which was compatible with CIDP. However, repeated intravenous IVIG (2 g/kg) treatment gave only a partial response. Four days after the last discharge, he was diagnosed as appendiceal CD after surgical resection of a periappendiceal abscess. His neurologic symptoms and electrophysiologic findings recovered without any maintenance therapy. CIDP-like neuropathy can be an initial presentation of CD, and recovery of the CIDP symptoms may result from resection of the CD. Clinicians should be aware of the possibility of CD in patients with intractable CIDP symptoms.

White Dwarf Asteroseismology and the 12C(α,γ)16O Rate

NASA Astrophysics Data System (ADS)

Metcalfe, Travis S.

2003-04-01

Due to a new global analysis method, it is now possible to measure the internal composition of pulsating white dwarf stars, even with relatively simple theoretical models. The precise internal mixture of carbon and oxygen is the largest single source of uncertainty in ages derived from white dwarf cosmochronometry, and it contains information about the rate of the astrophysically important, but experimentally uncertain, 12C(α,γ)16O nuclear reaction. Recent determinations of the internal composition and structure of two helium-atmosphere variable (DBV) white dwarf stars, GD 358 and CBS 114, initially led to conflicting implied rates for the 12C(α,γ)16O reaction. If both stars were formed through single-star evolution, then the initial analyses of their pulsation frequencies must have differed in some systematic way. I present improved fits to the two sets of pulsation data, resolving the tension between the initial results and leading to a value for the 12C(α,γ)16O reaction rate that is consistent with recent laboratory measurements.

Long-range strategic planning: a case study.

PubMed

Moller-Tiger, D

1999-05-01

In highly competitive healthcare markets, integrated delivery systems (IDSs) that have exhausted traditional means of maintaining market competitiveness are challenged to identify effective new strategies that will ensure market success in an uncertain future. Finding itself facing this challenge, Legacy Health System, a Portland, Oregon-based IDS, undertook an innovative, long-range, strategic-planning initiative based on an evaluation of key market trends. Legacy discovered that it might benefit from making some changes in the way it approached its mission. These changes included focusing on specific customer segments, developing products and services aimed at those customers, and broadening physician and insurer relationships to enhance service and improve customers' access to health care.

Variety in planetary systems

NASA Technical Reports Server (NTRS)

Wetherill, George W.

1993-01-01

Observation of circumstellar disks, regular satellite systems of outer planets, and planet-size objects orbiting pulsars support the supposition that formation of planetary systems is a robust, rather than a fragile, byproduct of the formation and evolution of stars. The extent to which these systems may be expected to resemble one another and our Solar System, either in overall structure or in detail remains uncertain. When the full range of possible stellar masses, disk masses, and initial specific angular momenta are considered, the possible variety of planetary configurations is very large. Numerical modeling indicates a difference between the formation of small, inner, terrestrial planets and the outer planets.

Myxedema coma.

PubMed

Wartofsky, Leonard

2006-12-01

Myxedema coma is the term given to the most severe presentation of profound hypothyroidism and is often fatal in spite of therapy. Decompensation of the hypothyroid patient into a coma may be precipitated by a number of drugs, systemic illnesses (eg, pneumonia), and other causes. It typically presents in older women in the winter months and is associated with signs of hypothyroidism, hypothermia, hyponatremia, hypercarbia, and hypoxemia. Treatment must be initiated promptly in an intensive care unit setting. Although thyroid hormone therapy is critical to survival, it remains uncertain whether it should be administered as thyroxine, triiodothyronine, or both. Adjunctive measures, such as ventilation, warming, fluids, antibiotics, pressors, and corticosteroids, may be essential for survival.

A gaseous metal disk around a white dwarf.

PubMed

Gänsicke, B T; Marsh, T R; Southworth, J; Rebassa-Mansergas, A

2006-12-22

The destiny of planetary systems through the late evolution of their host stars is very uncertain. We report a metal-rich gas disk around a moderately hot and young white dwarf. A dynamical model of the double-peaked emission lines constrains the outer disk radius to just 1.2 solar radii. The likely origin of the disk is a tidally disrupted asteroid, which has been destabilized from its initial orbit at a distance of more than 1000 solar radii by the interaction with a relatively massive planetesimal object or a planet. The white dwarf mass of 0.77 solar mass implies that planetary systems may form around high-mass stars.

Simple bone cyst of mandible mimicking periapical cyst

PubMed Central

HS, Charan Babu; Rai, Bhagawan Das; Nair, Manju A.; Astekar, Madhusudan S.

2012-01-01

Simple bone cysts (SBC) are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient. PMID:24765458

Altered subjective reward valuation among drug-deprived heavy marijuana users: Aversion to uncertainty

PubMed Central

Hefner, Kathryn R.; Starr, Mark. J.; Curtin, John. J.

2015-01-01

Marijuana is the most commonly used illicit drug in the United States and its use is rising. Nonetheless, scientific efforts to clarify the risk for addiction and other harm associated with marijuana use have been lacking. Maladaptive decision-making is a cardinal feature of addiction that is likely to emerge in heavy users. In particular, distorted subjective reward valuation related to homeostatic or allostatic processes has been implicated for many drugs of abuse. Selective changes in responses to uncertainty have been observed in response to intoxication and deprivation from various drugs of abuse. To assess for these potential neuroadaptive changes in reward valuation associated with marijuana deprivation, we examined the subjective value of uncertain and certain rewards among deprived and non-deprived heavy marijuana users in a behavioral economics decision-making task. Deprived users displayed reduced valuation of uncertain rewards, particularly when these rewards were more objectively valuable. This uncertainty aversion increased with increasing quantity of marijuana use. These results suggest comparable decision-making vulnerability from marijuana use as other drugs of abuse, and highlights targets for intervention. PMID:26595464

Boundary Control of Linear Uncertain 1-D Parabolic PDE Using Approximate Dynamic Programming.

PubMed

Talaei, Behzad; Jagannathan, Sarangapani; Singler, John

2018-04-01

This paper develops a near optimal boundary control method for distributed parameter systems governed by uncertain linear 1-D parabolic partial differential equations (PDE) by using approximate dynamic programming. A quadratic surface integral is proposed to express the optimal cost functional for the infinite-dimensional state space. Accordingly, the Hamilton-Jacobi-Bellman (HJB) equation is formulated in the infinite-dimensional domain without using any model reduction. Subsequently, a neural network identifier is developed to estimate the unknown spatially varying coefficient in PDE dynamics. Novel tuning law is proposed to guarantee the boundedness of identifier approximation error in the PDE domain. A radial basis network (RBN) is subsequently proposed to generate an approximate solution for the optimal surface kernel function online. The tuning law for near optimal RBN weights is created, such that the HJB equation error is minimized while the dynamics are identified and closed-loop system remains stable. Ultimate boundedness (UB) of the closed-loop system is verified by using the Lyapunov theory. The performance of the proposed controller is successfully confirmed by simulation on an unstable diffusion-reaction process.

Robust optimization of supersonic ORC nozzle guide vanes

NASA Astrophysics Data System (ADS)

Bufi, Elio A.; Cinnella, Paola

2017-03-01

An efficient Robust Optimization (RO) strategy is developed for the design of 2D supersonic Organic Rankine Cycle turbine expanders. The dense gas effects are not-negligible for this application and they are taken into account describing the thermodynamics by means of the Peng-Robinson-Stryjek-Vera equation of state. The design methodology combines an Uncertainty Quantification (UQ) loop based on a Bayesian kriging model of the system response to the uncertain parameters, used to approximate statistics (mean and variance) of the uncertain system output, a CFD solver, and a multi-objective non-dominated sorting algorithm (NSGA), also based on a Kriging surrogate of the multi-objective fitness function, along with an adaptive infill strategy for surrogate enrichment at each generation of the NSGA. The objective functions are the average and variance of the isentropic efficiency. The blade shape is parametrized by means of a Free Form Deformation (FFD) approach. The robust optimal blades are compared to the baseline design (based on the Method of Characteristics) and to a blade obtained by means of a deterministic CFD-based optimization.

Using Markov Models of Fault Growth Physics and Environmental Stresses to Optimize Control Actions

NASA Technical Reports Server (NTRS)

Bole, Brian; Goebel, Kai; Vachtsevanos, George

2012-01-01

A generalized Markov chain representation of fault dynamics is presented for the case that available modeling of fault growth physics and future environmental stresses can be represented by two independent stochastic process models. A contrived but representatively challenging example will be presented and analyzed, in which uncertainty in the modeling of fault growth physics is represented by a uniformly distributed dice throwing process, and a discrete random walk is used to represent uncertain modeling of future exogenous loading demands to be placed on the system. A finite horizon dynamic programming algorithm is used to solve for an optimal control policy over a finite time window for the case that stochastic models representing physics of failure and future environmental stresses are known, and the states of both stochastic processes are observable by implemented control routines. The fundamental limitations of optimization performed in the presence of uncertain modeling information are examined by comparing the outcomes obtained from simulations of an optimizing control policy with the outcomes that would be achievable if all modeling uncertainties were removed from the system.

Adaptive control of nonlinear uncertain active suspension systems with prescribed performance.

PubMed

Huang, Yingbo; Na, Jing; Wu, Xing; Liu, Xiaoqin; Guo, Yu

2015-01-01

This paper proposes adaptive control designs for vehicle active suspension systems with unknown nonlinear dynamics (e.g., nonlinear spring and piece-wise linear damper dynamics). An adaptive control is first proposed to stabilize the vertical vehicle displacement and thus to improve the ride comfort and to guarantee other suspension requirements (e.g., road holding and suspension space limitation) concerning the vehicle safety and mechanical constraints. An augmented neural network is developed to online compensate for the unknown nonlinearities, and a novel adaptive law is developed to estimate both NN weights and uncertain model parameters (e.g., sprung mass), where the parameter estimation error is used as a leakage term superimposed on the classical adaptations. To further improve the control performance and simplify the parameter tuning, a prescribed performance function (PPF) characterizing the error convergence rate, maximum overshoot and steady-state error is used to propose another adaptive control. The stability for the closed-loop system is proved and particular performance requirements are analyzed. Simulations are included to illustrate the effectiveness of the proposed control schemes. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Combined Retrievals of Boreal Forest Fire Aerosol Properties with a Polarimeter and Lidar

NASA Technical Reports Server (NTRS)

Knobelspiesse, K.; Cairns, B.; Ottaviani, M.; Ferrare, R.; Haire, J.; Hostetler, C.; Obland, M.; Rogers, R.; Redemann, J.; Shinozuka, Y.;

Common-envelope ejection in massive binary stars. Implications for the progenitors of GW150914 and GW151226

NASA Astrophysics Data System (ADS)

Kruckow, M. U.; Tauris, T. M.; Langer, N.; Szécsi, D.; Marchant, P.; Podsiadlowski, Ph.

2016-11-01

Context. The recently detected gravitational wave signals (GW150914 and GW151226) of the merger event of a pair of relatively massive stellar-mass black holes (BHs) calls for an investigation of the formation of such progenitor systems in general. Aims: We analyse the common-envelope (CE) stage of the traditional formation channel in binaries where the first-formed compact object undergoes an in-spiral inside the envelope of its evolved companion star and ejects the envelope in this process. Methods: We calculated envelope binding energies of donor stars with initial masses between 4 and 115M⊙ for metallicities of Z = ZMilky Way ≃ Z⊙/ 2 and Z = Z⊙/ 50, and derived minimum masses of in-spiralling objects needed to eject these envelopes. Results: In addition to producing double white dwarf and double neutron star binaries, CE evolution may also produce massive BH-BH systems with individual BH component masses of up to 50 - 60M⊙, in particular for donor stars evolved to giants beyond the Hertzsprung gap. However, the physics of envelope ejection of massive stars remains uncertain. We discuss the applicability of the energy-budget formalism, the location of the bifurcation point, the recombination energy, and the accretion energy during in-spiral as possible energy sources, and also comment on the effect of inflated helium cores. Conclusions: Massive stars in a wide range of metallicities and with initial masses of up to at least 115M⊙ may shed their envelopes and survive CE evolution, depending on their initial orbital parameters, similarly to the situation for intermediate- and low-mass stars with degenerate cores. In addition to being dependent on stellar radius, the envelope binding energies and λ-values also depend on the applied convective core-overshooting parameter, whereas these structure parameters are basically independent of metallicity for stars with initial masses below 60M⊙. Metal-rich stars ≳60M⊙ become luminous blue variables and do not evolve to reach the red giant stage. We conclude that based on stellar structure calculations, and in the view of the usual simple energy budget analysis, events like GW150914 and GW151226 might be produced by the CE channel. Calculations of post-CE orbital separations, however, and thus the estimated LIGO detection rates, remain highly uncertain.

Altered brain activation and connectivity during anticipation of uncertain threat in trait anxiety.

PubMed

Geng, Haiyang; Wang, Yi; Gu, Ruolei; Luo, Yue-Jia; Xu, Pengfei; Huang, Yuxia; Li, Xuebing

2018-06-08

In the research field of anxiety, previous studies generally focus on emotional responses following threat. A recent model of anxiety proposes that altered anticipation prior to uncertain threat is related with the development of anxiety. Behavioral findings have built the relationship between anxiety and distinct anticipatory processes including attention, estimation of threat, and emotional responses. However, few studies have characterized the brain organization underlying anticipation of uncertain threat and its role in anxiety. In the present study, we used an emotional anticipation paradigm with functional magnetic resonance imaging (fMRI) to examine the aforementioned topics by employing brain activation and general psychophysiological interactions (gPPI) analysis. In the activation analysis, we found that high trait anxious individuals showed significantly increased activation in the thalamus, middle temporal gyrus (MTG), and dorsomedial prefrontal cortex (dmPFC), as well as decreased activation in the precuneus, during anticipation of uncertain threat compared to the certain condition. In the gPPI analysis, the key regions including the amygdala, dmPFC, and precuneus showed altered connections with distributed brain areas including the ventromedial prefrontal cortex (vmPFC), dorsolateral prefrontal cortex (dlPFC), inferior parietal sulcus (IPS), insula, para-hippocampus gyrus (PHA), thalamus, and MTG involved in anticipation of uncertain threat in anxious individuals. Taken together, our findings indicate that during the anticipation of uncertain threat, anxious individuals showed altered activations and functional connectivity in widely distributed brain areas, which may be critical for abnormal perception, estimation, and emotion reactions during the anticipation of uncertain threat. © 2018 Wiley Periodicals, Inc.

Is the whole the sum of its parts? Agent-based modelling of wastewater treatment systems.

PubMed

Schuler, A J; Majed, N; Bucci, V; Hellweger, F L; Tu, Y; Gu, A Z

2011-01-01

Agent-based models (ABMS) simulate individual units within a system, such as the bacteria in a biological wastewater treatment system. This paper outlines past, current and potential future applications of ABMs to wastewater treatment. ABMs track heterogeneities within microbial populations, and this has been demonstrated to yield different predictions of bulk behaviors than the conventional, "lumped" approaches for enhanced biological phosphorus removal (EBPR) completely mixed reactors systems. Current work included the application of the ABM approach to bacterial adaptation/evolution, using the model system of individual EBPR bacteria that are allowed to evolve a kinetic parameter (maximum glycogen storage) in a competitive environment. The ABM approach was successfully implemented to a simple anaerobic-aerobic system and it was found the differing initial states converged to the same optimal solution under uncertain hydraulic residence times associated with completely mixed hydraulics. In another study, an ABM was developed and applied to simulate the heterogeneity in intracellular polymer storage compounds, including polyphosphate (PP), in functional microbial populations in enhanced biological phosphorus removal (EBPR) process. The simulation results were compared to the experimental measurements of single-cell abundance of PP in polyphosphate accumulating organisms (PAOs), performed using Raman microscopy. The model-predicted heterogeneity was generally consistent with observations, and it was used to investigate the relative contribution of external (different life histories) and internal (biological) mechanisms leading to heterogeneity. In the future, ABMs could be combined with computational fluid dynamics (CFD) models to understand incomplete mixing, more intracellular states and mechanisms can be incorporated, and additional experimental verification is needed.

Sustainable Water Resources for Communities under Climate Change: Can State-of-the-Art Forecasting Inform Decision-Making in Data Sparse Regions?

NASA Astrophysics Data System (ADS)

Mayer, A.; Vivoni, E.; Halvorsen, K.; Robles-Morua, A.; Dana, K.; Che, D.; Mirchi, A.; Kossak, D.; Casteneda, M.

2013-05-01

In this project, we are studying decision-making for water resources management in anticipation of climate change in the Sonora River Basin, Mexico as a case study for the broader arid and semiarid southwestern North America. The goal of the proposed project is to determine whether water resources systems modeling, developed within a participatory framework, can contribute to the building of management strategies in a context of water scarcity, conflicting water uses and highly variable and changing climate conditions. The participatory modeling approach will be conducted through a series of three workshops, designed to encourage substantive participation from a broad range of actors, including representatives from federal and local government agencies, water use sectors, non-governmental organizations, and academics. Participants will guide the design of supply- and demand-side management strategies and selection of climate change and infrastructure management scenarios using state-of-the-art engineering tools. These tools include a water resources systems framework, a spatially-explicit hydrologic model, the use of forecasted climate scenarios under 21st century climate change, and observations obtained from field and satellite sensors. Through the theory of planned behavior, the participatory modeling process will be evaluated to understand if, and to what extent, the engineering tools are useful in the uncertain and politically-complex setting. Pre- and post-workshop surveys will be used in this evaluation. For this contribution, we present the results of the first collaborative modeling workshop that will be held in March 2013, where we will develop the initial modeling framework in collaboration with workshop participants.

Robust LS-SVM-based adaptive constrained control for a class of uncertain nonlinear systems with time-varying predefined performance

NASA Astrophysics Data System (ADS)

Luo, Jianjun; Wei, Caisheng; Dai, Honghua; Yuan, Jianping

2018-03-01

This paper focuses on robust adaptive control for a class of uncertain nonlinear systems subject to input saturation and external disturbance with guaranteed predefined tracking performance. To reduce the limitations of classical predefined performance control method in the presence of unknown initial tracking errors, a novel predefined performance function with time-varying design parameters is first proposed. Then, aiming at reducing the complexity of nonlinear approximations, only two least-square-support-vector-machine-based (LS-SVM-based) approximators with two design parameters are required through norm form transformation of the original system. Further, a novel LS-SVM-based adaptive constrained control scheme is developed under the time-vary predefined performance using backstepping technique. Wherein, to avoid the tedious analysis and repeated differentiations of virtual control laws in the backstepping technique, a simple and robust finite-time-convergent differentiator is devised to only extract its first-order derivative at each step in the presence of external disturbance. In this sense, the inherent demerit of backstepping technique-;explosion of terms; brought by the recursive virtual controller design is conquered. Moreover, an auxiliary system is designed to compensate the control saturation. Finally, three groups of numerical simulations are employed to validate the effectiveness of the newly developed differentiator and the proposed adaptive constrained control scheme.

Planetary micro-rover operations on Mars using a Bayesian framework for inference and control

NASA Astrophysics Data System (ADS)

Post, Mark A.; Li, Junquan; Quine, Brendan M.

2016-03-01

With the recent progress toward the application of commercially-available hardware to small-scale space missions, it is now becoming feasible for groups of small, efficient robots based on low-power embedded hardware to perform simple tasks on other planets in the place of large-scale, heavy and expensive robots. In this paper, we describe design and programming of the Beaver micro-rover developed for Northern Light, a Canadian initiative to send a small lander and rover to Mars to study the Martian surface and subsurface. For a small, hardware-limited rover to handle an uncertain and mostly unknown environment without constant management by human operators, we use a Bayesian network of discrete random variables as an abstraction of expert knowledge about the rover and its environment, and inference operations for control. A framework for efficient construction and inference into a Bayesian network using only the C language and fixed-point mathematics on embedded hardware has been developed for the Beaver to make intelligent decisions with minimal sensor data. We study the performance of the Beaver as it probabilistically maps a simple outdoor environment with sensor models that include uncertainty. Results indicate that the Beaver and other small and simple robotic platforms can make use of a Bayesian network to make intelligent decisions in uncertain planetary environments.

Applied estimation for hybrid dynamical systems using perceptional information

NASA Astrophysics Data System (ADS)

Plotnik, Aaron M.

This dissertation uses the motivating example of robotic tracking of mobile deep ocean animals to present innovations in robotic perception and estimation for hybrid dynamical systems. An approach to estimation for hybrid systems is presented that utilizes uncertain perceptional information about the system's mode to improve tracking of its mode and continuous states. This results in significant improvements in situations where previously reported methods of estimation for hybrid systems perform poorly due to poor distinguishability of the modes. The specific application that motivates this research is an automatic underwater robotic observation system that follows and films individual deep ocean animals. A first version of such a system has been developed jointly by the Stanford Aerospace Robotics Laboratory and Monterey Bay Aquarium Research Institute (MBARI). This robotic observation system is successfully fielded on MBARI's ROVs, but agile specimens often evade the system. When a human ROV pilot performs this task, one advantage that he has over the robotic observation system in these situations is the ability to use visual perceptional information about the target, immediately recognizing any changes in the specimen's behavior mode. With the approach of the human pilot in mind, a new version of the robotic observation system is proposed which is extended to (a) derive perceptional information (visual cues) about the behavior mode of the tracked specimen, and (b) merge this dissimilar, discrete and uncertain information with more traditional continuous noisy sensor data by extending existing algorithms for hybrid estimation. These performance enhancements are enabled by integrating techniques in hybrid estimation, computer vision and machine learning. First, real-time computer vision and classification algorithms extract a visual observation of the target's behavior mode. Existing hybrid estimation algorithms are extended to admit this uncertain but discrete observation, complementing the information available from more traditional sensors. State tracking is achieved using a new form of Rao-Blackwellized particle filter called the mode-observed Gaussian Particle Filter. Performance is demonstrated using data from simulation and data collected on actual specimens in the ocean. The framework for estimation using both traditional and perceptional information is easily extensible to other stochastic hybrid systems with mode-related perceptional observations available.

Genetic purgatory and the cardiac channelopathies: Exposing the variants of uncertain/unknown significance issue.

PubMed

Ackerman, Michael J

2015-11-01

Merriam-Webster's online dictionary defines purgatory as "an intermediate state after death for expiatory purification" or more specifically as "a place or state of punishment wherein according to Roman Catholic doctrine the souls of those who die in God׳s grace may make satisfaction for past sins and so become fit for heaven." Alternatively, it is defined as "a place or state of temporary suffering or misery." Either way, purgatory is a place where you are stuck, and you don't want to be stuck there. It is in this context that the term genetic purgatory is introduced. Genetic purgatory is a place where the genetic test-ordering physician and patients and their families are stuck when a variant of uncertain/unknown significance (VUS) has been elucidated. It is in this dark place where suffering and misery are occurring because of unenlightened handling of a VUS, which includes using the VUS for predictive genetic testing and making radical treatment recommendations based on the presence or absence of a so-called maybe mutation. Before one can escape from this miserable place, one must first recognize that one is stuck there. Hence, the purpose of this review article is to fully expose the VUS issue as it relates to the cardiac channelopathies and make the cardiologists/geneticists/genetic counselors who order such genetic tests believers in genetic purgatory. Only then can one meaningfully attempt to get out of that place and seek to promote a VUS to disease-causative mutation status or demote it to an utterly innocuous and irrelevant variant. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

A Gompertz population model with Allee effect and fuzzy initial values

NASA Astrophysics Data System (ADS)

Amarti, Zenia; Nurkholipah, Nenden Siti; Anggriani, Nursanti; Supriatna, Asep K.

2018-03-01

Growth and population dynamics models are important tools used in preparing a good management for society to predict the future of population or species. This has been done by various known methods, one among them is by developing a mathematical model that describes population growth. Models are usually formed into differential equations or systems of differential equations, depending on the complexity of the underlying properties of the population. One example of biological complexity is Allee effect. It is a phenomenon showing a high correlation between very small population size and the mean individual fitness of the population. In this paper the population growth model used is the Gompertz equation model by considering the Allee effect on the population. We explore the properties of the solution to the model numerically using the Runge-Kutta method. Further exploration is done via fuzzy theoretical approach to accommodate uncertainty of the initial values of the model. It is known that an initial value greater than the Allee threshold will cause the solution rises towards carrying capacity asymptotically. However, an initial value smaller than the Allee threshold will cause the solution decreases towards zero asymptotically, which means the population is eventually extinct. Numerical solutions show that modeling uncertain initial value of the critical point A (the Allee threshold) with a crisp initial value could cause the extinction of population of a certain possibilistic degree, depending on the predetermined membership function of the initial value.

Analysis of Implicit Uncertain Systems. Part 1: Theoretical Framework

DTIC Science & Technology

1994-12-07

Analysis of Implicit Uncertain Systems Part I: Theoretical Framework Fernando Paganini * John Doyle 1 December 7, 1994 Abst rac t This paper...Analysis of Implicit Uncertain Systems Part I: Theoretical Framework 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...model and a number of constraints relevant to the analysis problem under consideration. In Part I of this paper we propose a theoretical framework which

Research of Uncertainty Reasoning in Pineapple Disease Identification System

NASA Astrophysics Data System (ADS)

Liu, Liqun; Fan, Haifeng

In order to deal with the uncertainty of evidences mostly existing in pineapple disease identification system, a reasoning model based on evidence credibility factor was established. The uncertainty reasoning method is discussed,including: uncertain representation of knowledge, uncertain representation of rules, uncertain representation of multi-evidences and update of reasoning rules. The reasoning can fully reflect the uncertainty in disease identification and reduce the influence of subjective factors on the accuracy of the system.

Scheduling in the Face of Uncertain Resource Consumption and Utility

NASA Technical Reports Server (NTRS)

Frank, Jeremy; Dearden, Richard

2003-01-01

We discuss the problem of scheduling tasks that consume uncertain amounts of a resource with known capacity and where the tasks have uncertain utility. In these circumstances, we would like to find schedules that exceed a lower bound on the expected utility when executed. We show that the problems are NP- complete, and present some results that characterize the behavior of some simple heuristics over a variety of problem classes.

Quaternary tectonic faulting in the Eastern United States

USGS Publications Warehouse

Wheeler, R.L.

2006-01-01

Paleoseismological study of geologic features thought to result from Quaternary tectonic faulting can characterize the frequencies and sizes of large prehistoric and historical earthquakes, thereby improving the accuracy and precision of seismic-hazard assessments. Greater accuracy and precision can reduce the likelihood of both underprotection and unnecessary design and construction costs. Published studies proposed Quaternary tectonic faulting at 31 faults, folds, seismic zones, and fields of earthquake-induced liquefaction phenomena in the Appalachian Mountains and Coastal Plain. Of the 31 features, seven are of known origin. Four of the seven have nontectonic origins and the other three features are liquefaction fields caused by moderate to large historical and Holocene earthquakes in coastal South Carolina, including Charleston; the Central Virginia Seismic Zone; and the Newbury, Massachusetts, area. However, the causal faults of the three liquefaction fields remain unclear. Charleston has the highest hazard because of large Holocene earthquakes in that area, but the hazard is highly uncertain because the earthquakes are uncertainly located. Of the 31 features, the remaining 24 are of uncertain origin. They require additional work before they can be clearly attributed either to Quaternary tectonic faulting or to nontectonic causes. Of these 24, 14 features, most of them faults, have little or no published geologic evidence of Quaternary tectonic faulting that could indicate the likely occurrence of earthquakes larger than those observed historically. Three more features of the 24 were suggested to have had Quaternary tectonic faulting, but paleoseismological and other studies of them found no evidence of large prehistoric earthquakes. The final seven features of uncertain origin require further examination because all seven are in or near urban areas. They are the Moodus Seismic Zone (Hartford, Connecticut), Dobbs Ferry fault zone and Mosholu fault (New York City), Lancaster Seismic Zone and the epicenter of the shallow Cacoosing Valley earthquake (Lancaster and Reading, Pennsylvania), Kingston fault (central New Jersey between New York and Philadelphia), and Everona fault-Mountain Run fault zone (Washington, D.C., and Arlington and Alexandria, Virginia). ?? 2005 Elsevier B.V. All rights reserved.

Joint estimation over multiple individuals improves behavioural state inference from animal movement data.

PubMed

Jonsen, Ian

2016-02-08

State-space models provide a powerful way to scale up inference of movement behaviours from individuals to populations when the inference is made across multiple individuals. Here, I show how a joint estimation approach that assumes individuals share identical movement parameters can lead to improved inference of behavioural states associated with different movement processes. I use simulated movement paths with known behavioural states to compare estimation error between nonhierarchical and joint estimation formulations of an otherwise identical state-space model. Behavioural state estimation error was strongly affected by the degree of similarity between movement patterns characterising the behavioural states, with less error when movements were strongly dissimilar between states. The joint estimation model improved behavioural state estimation relative to the nonhierarchical model for simulated data with heavy-tailed Argos location errors. When applied to Argos telemetry datasets from 10 Weddell seals, the nonhierarchical model estimated highly uncertain behavioural state switching probabilities for most individuals whereas the joint estimation model yielded substantially less uncertainty. The joint estimation model better resolved the behavioural state sequences across all seals. Hierarchical or joint estimation models should be the preferred choice for estimating behavioural states from animal movement data, especially when location data are error-prone.

Modeling the Near-Term Risk of Climate Uncertainty: Interdependencies among the U.S. States

NASA Astrophysics Data System (ADS)

Lowry, T. S.; Backus, G.; Warren, D.

2010-12-01

Decisions made to address climate change must start with an understanding of the risk of an uncertain future to human systems, which in turn means understanding both the consequence as well as the probability of a climate induced impact occurring. In other words, addressing climate change is an exercise in risk-informed policy making, which implies that there is no single correct answer or even a way to be certain about a single answer; the uncertainty in future climate conditions will always be present and must be taken as a working-condition for decision making. In order to better understand the implications of uncertainty on risk and to provide a near-term rationale for policy interventions, this study estimates the impacts from responses to climate change on U.S. state- and national-level economic activity by employing a risk-assessment methodology for evaluating uncertain future climatic conditions. Using the results from the Intergovernmental Panel on Climate Change’s (IPCC) Fourth Assessment Report (AR4) as a proxy for climate uncertainty, changes in hydrology over the next 40 years were mapped and then modeled to determine the physical consequences on economic activity and to perform a detailed 70-industry analysis of the economic impacts among the interacting lower-48 states. The analysis determines industry-level effects, employment impacts at the state level, interstate population migration, consequences to personal income, and ramifications for the U.S. trade balance. The conclusions show that the average risk of damage to the U.S. economy from climate change is on the order of $1 trillion over the next 40 years, with losses in employment equivalent to nearly 7 million full-time jobs. Further analysis shows that an increase in uncertainty raises this risk. This paper will present the methodology behind the approach, a summary of the underlying models, as well as the path forward for improving the approach.

Gill Na+,K+-ATPase of Atlantic salmon smolts in freshwater is not a predictor of long-term growth in seawater

USGS Publications Warehouse

Zydlewski, Gayle B.; Zydlewski, Joseph D.

2012-01-01

Gill Na+,K+-ATPase activity is a widely used measure of osmoregulatory preparedness in salmonid smolts. The degree to which this measure may predict long term performance is uncertain. In order to assess the relationship of this enzyme to long term growth and ion homeostasis, a cohort of Atlantic salmon hatchery smolts was used in a controlled environment with no salinity perturbations. In May 2006, gill Na+,K+-ATPase activity from 940 individually PIT tagged, Penobscot River smolts (USFWS, Green Lake National Fish Hatchery, Maine, United States) was measured immediately prior to isothermal transfer from freshwater to 32 ppt seawater. From the observed range of activities, individuals were classified as having “low”, “middle”, or “high” enzyme activity levels. Individual size (fork length and mass) was recorded on days 0, 1, 3, and 14 and monthly for four months. Growth rates over four time periods were calculated for individual fish maintained until the end of the experiment. Gill Na+,K+-ATPase activities were also measured from a subset of sampled fish. All groups effectively osmoregulated as evidenced by minor perturbations in plasma osmolyte levels. Apart from initial weight loss on transfer, fish grew throughout the experiment, however, there were no differences (fish size, growth rate, and gill Na+,K+-ATPase activity in seawater) among groups with initially different gill Na+,K+-ATPase activities (prior to seawater entry). While gill Na+,K+-ATPase activity may be predictive of performance during the acute phase of acclimation (first few days), typical variation in this enzyme, expressed in freshwater at the peak of smolting, does not appear to be predictive of long-term growth in seawater.

A Community Standard Format for the Representation of Protein Affinity Reagents*

PubMed Central

Gloriam, David E.; Orchard, Sandra; Bertinetti, Daniela; Björling, Erik; Bongcam-Rudloff, Erik; Borrebaeck, Carl A. K.; Bourbeillon, Julie; Bradbury, Andrew R. M.; de Daruvar, Antoine; Dübel, Stefan; Frank, Ronald; Gibson, Toby J.; Gold, Larry; Haslam, Niall; Herberg, Friedrich W.; Hiltke, Tara; Hoheisel, Jörg D.; Kerrien, Samuel; Koegl, Manfred; Konthur, Zoltán; Korn, Bernhard; Landegren, Ulf; Montecchi-Palazzi, Luisa; Palcy, Sandrine; Rodriguez, Henry; Schweinsberg, Sonja; Sievert, Volker; Stoevesandt, Oda; Taussig, Michael J.; Ueffing, Marius; Uhlén, Mathias; van der Maarel, Silvère; Wingren, Christer; Woollard, Peter; Sherman, David J.; Hermjakob, Henning

2010-01-01

Protein affinity reagents (PARs), most commonly antibodies, are essential reagents for protein characterization in basic research, biotechnology, and diagnostics as well as the fastest growing class of therapeutics. Large numbers of PARs are available commercially; however, their quality is often uncertain. In addition, currently available PARs cover only a fraction of the human proteome, and their cost is prohibitive for proteome scale applications. This situation has triggered several initiatives involving large scale generation and validation of antibodies, for example the Swedish Human Protein Atlas and the German Antibody Factory. Antibodies targeting specific subproteomes are being pursued by members of Human Proteome Organisation (plasma and liver proteome projects) and the United States National Cancer Institute (cancer-associated antigens). ProteomeBinders, a European consortium, aims to set up a resource of consistently quality-controlled protein-binding reagents for the whole human proteome. An ultimate PAR database resource would allow consumers to visit one on-line warehouse and find all available affinity reagents from different providers together with documentation that facilitates easy comparison of their cost and quality. However, in contrast to, for example, nucleotide databases among which data are synchronized between the major data providers, current PAR producers, quality control centers, and commercial companies all use incompatible formats, hindering data exchange. Here we propose Proteomics Standards Initiative (PSI)-PAR as a global community standard format for the representation and exchange of protein affinity reagent data. The PSI-PAR format is maintained by the Human Proteome Organisation PSI and was developed within the context of ProteomeBinders by building on a mature proteomics standard format, PSI-molecular interaction, which is a widely accepted and established community standard for molecular interaction data. Further information and documentation are available on the PSI-PAR web site. PMID:19674966

The Source Inversion Validation (SIV) Initiative: A Collaborative Study on Uncertainty Quantification in Earthquake Source Inversions

NASA Astrophysics Data System (ADS)

Mai, P. M.; Schorlemmer, D.; Page, M.

2012-04-01

Earthquake source inversions image the spatio-temporal rupture evolution on one or more fault planes using seismic and/or geodetic data. Such studies are critically important for earthquake seismology in general, and for advancing seismic hazard analysis in particular, as they reveal earthquake source complexity and help (i) to investigate earthquake mechanics; (ii) to develop spontaneous dynamic rupture models; (iii) to build models for generating rupture realizations for ground-motion simulations. In applications (i - iii), the underlying finite-fault source models are regarded as "data" (input information), but their uncertainties are essentially unknown. After all, source models are obtained from solving an inherently ill-posed inverse problem to which many a priori assumptions and uncertain observations are applied. The Source Inversion Validation (SIV) project is a collaborative effort to better understand the variability between rupture models for a single earthquake (as manifested in the finite-source rupture model database) and to develop robust uncertainty quantification for earthquake source inversions. The SIV project highlights the need to develop a long-standing and rigorous testing platform to examine the current state-of-the-art in earthquake source inversion, and to develop and test novel source inversion approaches. We will review the current status of the SIV project, and report the findings and conclusions of the recent workshops. We will briefly discuss several source-inversion methods, how they treat uncertainties in data, and assess the posterior model uncertainty. Case studies include initial forward-modeling tests on Green's function calculations, and inversion results for synthetic data from spontaneous dynamic crack-like strike-slip earthquake on steeply dipping fault, embedded in a layered crustal velocity-density structure.

A new large initial condition ensemble to assess avoided impacts in a climate mitigation scenario

NASA Astrophysics Data System (ADS)

Sanderson, B. M.; Tebaldi, C.; Knutti, R.; Oleson, K. W.

2014-12-01

It has recently been demonstrated that when considering timescales of up to 50 years, natural variability may play an equal role to anthropogenic forcing on subcontinental trends for a variety of climate indicators. Thus, for many questions assessing climate impacts on such time and spatial scales, it has become clear that a significant number of ensemble members may be required to produce robust statistics (and especially so for extreme events). However, large ensemble experiments to date have considered the role of variability in a single scenario, leaving uncertain the relationship between the forced climate trajectory and the variability about that path. To address this issue, we present a new, publicly available, 15 member initial condition ensemble of 21st century climate projections for the RCP 4.5 scenario using the CESM1.1 Earth System Model, which we propose as a companion project to the existing 40 member CESM large ensemble which uses the higher greenhouse gas emission future of RCP8.5. This provides a valuable data set for assessing what societal and ecological impacts might be avoided through a moderate mitigation strategy in contrast to a fossil fuel intensive future. We present some early analyses of these combined ensembles to assess to what degree the climate variability can be considered to combine linearly with the underlying forced response. In regions where there is no detectable relationship between the mean state and the variability about the mean trajectory, then linear assumptions can be trivially exploited to utilize a single ensemble or control simulation to characterize the variability in any scenario of interest. We highlight regions where there is a detectable nonlinearity in extreme event frequency, how far in the future they will be manifested and propose mechanisms to account for these effects.

A modified hybrid uncertain analysis method for dynamic response field of the LSOAAC with random and interval parameters

NASA Astrophysics Data System (ADS)

Zi, Bin; Zhou, Bin

2016-07-01

For the prediction of dynamic response field of the luffing system of an automobile crane (LSOAAC) with random and interval parameters, a hybrid uncertain model is introduced. In the hybrid uncertain model, the parameters with certain probability distribution are modeled as random variables, whereas, the parameters with lower and upper bounds are modeled as interval variables instead of given precise values. Based on the hybrid uncertain model, the hybrid uncertain dynamic response equilibrium equation, in which different random and interval parameters are simultaneously included in input and output terms, is constructed. Then a modified hybrid uncertain analysis method (MHUAM) is proposed. In the MHUAM, based on random interval perturbation method, the first-order Taylor series expansion and the first-order Neumann series, the dynamic response expression of the LSOAAC is developed. Moreover, the mathematical characteristics of extrema of bounds of dynamic response are determined by random interval moment method and monotonic analysis technique. Compared with the hybrid Monte Carlo method (HMCM) and interval perturbation method (IPM), numerical results show the feasibility and efficiency of the MHUAM for solving the hybrid LSOAAC problems. The effects of different uncertain models and parameters on the LSOAAC response field are also investigated deeply, and numerical results indicate that the impact made by the randomness in the thrust of the luffing cylinder F is larger than that made by the gravity of the weight in suspension Q . In addition, the impact made by the uncertainty in the displacement between the lower end of the lifting arm and the luffing cylinder a is larger than that made by the length of the lifting arm L .

State of the states on brownfields programs for cleanup and reuse of contaminated sites

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

NONE

Brownfields consist of land and/or buildings that are abandoned or underutilized where expansion or redevelopment is complicated, in part, because of the threat of known or potential contamination. Federal and state laws governing the treatment of these sites may require remediation (cleanup) of property before redevelopment and can contribute to uncertain liability for property owners or users. Congress, in considering the reauthorization of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), commonly known as Superfund, is interested in the issue of brownfields and in their potential return to productive use. As a result, the House Subcommittee on Commerce, Trademore » and Hazardous Materials of the Committee on Commerce requested the Office of Technology Assessment (OTA) to prepare a background paper on issues surrounding cleanup and redevelopment of brownfields.« less

Iterative LQG Controller Design Through Closed-Loop Identification

NASA Technical Reports Server (NTRS)

Hsiao, Min-Hung; Huang, Jen-Kuang; Cox, David E.

1996-01-01

This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from the previous cycle. Then the identified open-loop model is used to redesign the state feedback. The state feedback and the identified Kalman filter gain are used to form an updated LQC controller for the next cycle. This iterative process continues until the updated controller converges. The proposed controller design is demonstrated by numerical simulations and experiments on a highly unstable large-gap magnetic suspension system.

Trait and state anxiety reduce the mere exposure effect

PubMed Central

Ladd, Sandra L.; Gabrieli, John D. E.

2015-01-01

The mere exposure effect refers to an affective preference elicited by exposure to previously unfamiliar items. Although it is a well-established finding, its mechanism remains uncertain, with some positing that it reflects affective processes and others positing that it reflects perceptual or motor fluency with repeated items. Here we examined whether individual differences in trait and state anxiety, which have been associated with the experience of emotion, influence the mere exposure effect. Participants’ trait (Study 1) and state (Study 2) anxiety were characterized with the State-Trait Anxiety Inventory. Greater trait and state anxiety correlated with greater negative affect and lesser positive affect. In both experiments, greater anxiety was associated with a reduced mere exposure effect. Measures of fluency (response times at study and test) were unrelated to the mere exposure effect. These findings support the role of affective processes in the mere exposure effect, and offer a new insight into the nature of anxiety such that anxiety is associated with a reduced experience of positive affect typically associated with familiarity. PMID:26074851

Trait and state anxiety reduce the mere exposure effect.

PubMed

Ladd, Sandra L; Gabrieli, John D E

2015-01-01

The mere exposure effect refers to an affective preference elicited by exposure to previously unfamiliar items. Although it is a well-established finding, its mechanism remains uncertain, with some positing that it reflects affective processes and others positing that it reflects perceptual or motor fluency with repeated items. Here we examined whether individual differences in trait and state anxiety, which have been associated with the experience of emotion, influence the mere exposure effect. Participants' trait (Study 1) and state (Study 2) anxiety were characterized with the State-Trait Anxiety Inventory. Greater trait and state anxiety correlated with greater negative affect and lesser positive affect. In both experiments, greater anxiety was associated with a reduced mere exposure effect. Measures of fluency (response times at study and test) were unrelated to the mere exposure effect. These findings support the role of affective processes in the mere exposure effect, and offer a new insight into the nature of anxiety such that anxiety is associated with a reduced experience of positive affect typically associated with familiarity.

MAGDM linear-programming models with distinct uncertain preference structures.

PubMed

Xu, Zeshui S; Chen, Jian

2008-10-01

Group decision making with preference information on alternatives is an interesting and important research topic which has been receiving more and more attention in recent years. The purpose of this paper is to investigate multiple-attribute group decision-making (MAGDM) problems with distinct uncertain preference structures. We develop some linear-programming models for dealing with the MAGDM problems, where the information about attribute weights is incomplete, and the decision makers have their preferences on alternatives. The provided preference information can be represented in the following three distinct uncertain preference structures: 1) interval utility values; 2) interval fuzzy preference relations; and 3) interval multiplicative preference relations. We first establish some linear-programming models based on decision matrix and each of the distinct uncertain preference structures and, then, develop some linear-programming models to integrate all three structures of subjective uncertain preference information provided by the decision makers and the objective information depicted in the decision matrix. Furthermore, we propose a simple and straightforward approach in ranking and selecting the given alternatives. It is worth pointing out that the developed models can also be used to deal with the situations where the three distinct uncertain preference structures are reduced to the traditional ones, i.e., utility values, fuzzy preference relations, and multiplicative preference relations. Finally, we use a practical example to illustrate in detail the calculation process of the developed approach.

Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment.

PubMed

Schnakers, Caroline; Vanhaudenhuyse, Audrey; Giacino, Joseph; Ventura, Manfredi; Boly, Melanie; Majerus, Steve; Moonen, Gustave; Laureys, Steven

2009-07-21

Previously published studies have reported that up to 43% of patients with disorders of consciousness are erroneously assigned a diagnosis of vegetative state (VS). However, no recent studies have investigated the accuracy of this grave clinical diagnosis. In this study, we compared consensus-based diagnoses of VS and MCS to those based on a well-established standardized neurobehavioral rating scale, the JFK Coma Recovery Scale-Revised (CRS-R). We prospectively followed 103 patients (55 +/- 19 years) with mixed etiologies and compared the clinical consensus diagnosis provided by the physician on the basis of the medical staff's daily observations to diagnoses derived from CRS-R assessments performed by research staff. All patients were assigned a diagnosis of 'VS', 'MCS' or 'uncertain diagnosis.' Of the 44 patients diagnosed with VS based on the clinical consensus of the medical team, 18 (41%) were found to be in MCS following standardized assessment with the CRS-R. In the 41 patients with a consensus diagnosis of MCS, 4 (10%) had emerged from MCS, according to the CRS-R. We also found that the majority of patients assigned an uncertain diagnosis by clinical consensus (89%) were in MCS based on CRS-R findings. Despite the importance of diagnostic accuracy, the rate of misdiagnosis of VS has not substantially changed in the past 15 years. Standardized neurobehavioral assessment is a more sensitive means of establishing differential diagnosis in patients with disorders of consciousness when compared to diagnoses determined by clinical consensus.

Exploring Representativeness and Informativeness for Active Learning.

PubMed

Du, Bo; Wang, Zengmao; Zhang, Lefei; Zhang, Liangpei; Liu, Wei; Shen, Jialie; Tao, Dacheng

2017-01-01

How can we find a general way to choose the most suitable samples for training a classifier? Even with very limited prior information? Active learning, which can be regarded as an iterative optimization procedure, plays a key role to construct a refined training set to improve the classification performance in a variety of applications, such as text analysis, image recognition, social network modeling, etc. Although combining representativeness and informativeness of samples has been proven promising for active sampling, state-of-the-art methods perform well under certain data structures. Then can we find a way to fuse the two active sampling criteria without any assumption on data? This paper proposes a general active learning framework that effectively fuses the two criteria. Inspired by a two-sample discrepancy problem, triple measures are elaborately designed to guarantee that the query samples not only possess the representativeness of the unlabeled data but also reveal the diversity of the labeled data. Any appropriate similarity measure can be employed to construct the triple measures. Meanwhile, an uncertain measure is leveraged to generate the informativeness criterion, which can be carried out in different ways. Rooted in this framework, a practical active learning algorithm is proposed, which exploits a radial basis function together with the estimated probabilities to construct the triple measures and a modified best-versus-second-best strategy to construct the uncertain measure, respectively. Experimental results on benchmark datasets demonstrate that our algorithm consistently achieves superior performance over the state-of-the-art active learning algorithms.

Processing uncertain RFID data in traceability supply chains.

PubMed

Xie, Dong; Xiao, Jie; Guo, Guangjun; Jiang, Tong

2014-01-01

Radio Frequency Identification (RFID) is widely used to track and trace objects in traceability supply chains. However, massive uncertain data produced by RFID readers are not effective and efficient to be used in RFID application systems. Following the analysis of key features of RFID objects, this paper proposes a new framework for effectively and efficiently processing uncertain RFID data, and supporting a variety of queries for tracking and tracing RFID objects. We adjust different smoothing windows according to different rates of uncertain data, employ different strategies to process uncertain readings, and distinguish ghost, missing, and incomplete data according to their apparent positions. We propose a comprehensive data model which is suitable for different application scenarios. In addition, a path coding scheme is proposed to significantly compress massive data by aggregating the path sequence, the position, and the time intervals. The scheme is suitable for cyclic or long paths. Moreover, we further propose a processing algorithm for group and independent objects. Experimental evaluations show that our approach is effective and efficient in terms of the compression and traceability queries.

Processing Uncertain RFID Data in Traceability Supply Chains

PubMed Central

Xie, Dong; Xiao, Jie

2014-01-01

Radio Frequency Identification (RFID) is widely used to track and trace objects in traceability supply chains. However, massive uncertain data produced by RFID readers are not effective and efficient to be used in RFID application systems. Following the analysis of key features of RFID objects, this paper proposes a new framework for effectively and efficiently processing uncertain RFID data, and supporting a variety of queries for tracking and tracing RFID objects. We adjust different smoothing windows according to different rates of uncertain data, employ different strategies to process uncertain readings, and distinguish ghost, missing, and incomplete data according to their apparent positions. We propose a comprehensive data model which is suitable for different application scenarios. In addition, a path coding scheme is proposed to significantly compress massive data by aggregating the path sequence, the position, and the time intervals. The scheme is suitable for cyclic or long paths. Moreover, we further propose a processing algorithm for group and independent objects. Experimental evaluations show that our approach is effective and efficient in terms of the compression and traceability queries. PMID:24737978

An Artificial Bee Colony Algorithm for Uncertain Portfolio Selection

PubMed Central

Chen, Wei

2014-01-01

Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts' evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is used to measure investment return, the uncertain variance of the return is used to measure investment risk, and the entropy is used to measure diversification degree of portfolio. In order to solve the proposed model, a modified artificial bee colony (ABC) algorithm is designed. Finally, a numerical example is given to illustrate the modelling idea and the effectiveness of the proposed algorithm. PMID:25089292

An artificial bee colony algorithm for uncertain portfolio selection.

PubMed

Chen, Wei

2014-01-01

Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts' evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is used to measure investment return, the uncertain variance of the return is used to measure investment risk, and the entropy is used to measure diversification degree of portfolio. In order to solve the proposed model, a modified artificial bee colony (ABC) algorithm is designed. Finally, a numerical example is given to illustrate the modelling idea and the effectiveness of the proposed algorithm.

Induction of belief decision trees from data

NASA Astrophysics Data System (ADS)

AbuDahab, Khalil; Xu, Dong-ling; Keane, John

2012-09-01

In this paper, a method for acquiring belief rule-bases by inductive inference from data is described and evaluated. Existing methods extract traditional rules inductively from data, with consequents that are believed to be either 100% true or 100% false. Belief rules can capture uncertain or incomplete knowledge using uncertain belief degrees in consequents. Instead of using singled-value consequents, each belief rule deals with a set of collectively exhaustive and mutually exclusive consequents. The proposed method extracts belief rules from data which contain uncertain or incomplete knowledge.

The Patient Protection and Affordable Care Act, public health, and the elusive target of human rights.

PubMed

Gable, Lance

2011-01-01

The Patient Protection and Affordable Care Act (ACA) sets in motion a wide range of programs that substantially affected the health system in the United States and signify a moderate but important regulatory shift in the role of the federal government in public health. This article briefly addresses two interesting policy paradoxes about the ACA. First, while the legislation primarily addresses health care financing and insurance and establishes only a few initiatives directly targeting public health, the ACA nevertheless has the potential to produce extensive public health benefits across the United States population by improving access to health care and services and reducing cost. Essentially, the ACA does not take the explicit form of a public health law but instead strives to advance public health indirectly through its effects. Second, while the ACA does not establish a right to health - or even a right to health insurance - in the United States, it does set in motion a number of significant structural and normative changes to United States law that comport with the attainment of the right to health. Most significantly, key provisions of the bill are designed to improve availability, accessibility, acceptability, and quality of conditions necessary for health, and to prompt the government to respect, protect, and fulfill these conditions. These developments mean that, to a degree, the United States essentially has undertaken the same types of legal and policy steps that a country would be required to take to uphold the right to health without actually recognizing the right to health in any formal or legally binding way. Despite these dual paradoxes and the upside potential for public health improvements resulting from the ACA, the public health impact of the law remains uncertain and will be decided by numerous subsequent regulatory and implementation decisions. The ACA authorizes multiple federal agencies to engage in rulemaking, a process that will largely dictate the systemic and health impacts that will become its legacy. This reality opens up ample opportunity to bolster public health aspects and interpretations of the law, and to simultaneously augment the corresponding components of the right to health. © 2011 American Society of Law, Medicine & Ethics, Inc.

The heterogeneous management of pediatric ankle traumas: A retrospective descriptive study.

PubMed

Voizard, Philippe; Moore, James; Leduc, Stéphane; Nault, Marie-Lyne

2018-06-01

Frequent misdiagnosis of pediatric ankle traumas leads to inappropriate management, which may result in residual pain, instability, slower return to physical activity, and long-term degenerative changes. The purpose of this study was to evaluate the consistency of diagnosis, management, and the treatment of acute lateral pediatric ankle trauma in a tertiary care pediatric hospital. The hypothesis was that the initial diagnosis is often incorrect, and the treatment varies considerably amongst orthopedic surgeons.We conducted a retrospective study of all cases of ankle sprains and Salter-Harris one (SH1) fractures referred to our orthopedic surgery service between May and August 2014. Exclusion criteria included ankle fractures other than SH1 types, and cases where treatment was initially undertaken elsewhere before referral to our service. Primary outcome was the difference between initial and final diagnosis.Among 3047 cases reviewed, 31 matched our inclusion criteria. Initial diagnosis was 20 SH1 fractures, 8 acute ankle sprains, and 3 uncertain, with a change in diagnosis for 48.5% at follow-up.Accurate diagnosis can be difficult in pediatric ankle trauma, with case management and specific treatments varying considerably. This study reinforces the need to evaluate the safety of a general treatment algorithm for all lateral ankle trauma with normal radiographs.Level of evidence III.

Meanings of care in health promotion.

PubMed

Falcón, Gladys Carmela Santos; Erdmann, Alacoque Lorenzini; Backes, Dirce Stein

2008-01-01

The objective of the study is to understand the meaning built by students and professors on health promotion in the teaching and learning process of health care in Nursing. It is a qualitative study using ground theory as a methodological reference. Data was collected through interviews, with three samples groups, 13 students and four professors, by classroom observation, and through meetings with nursing professors. The central subject resulting from this analysis was: constructing teaching and learning in order, disorder and self organization for a new way of caring promoting health. The teaching/learning process directed at health promotion develops in a stage of crisis, going from a state of order to a state of disorder that is uncertain and contradictory regarding what society understands about health.

Operational tools to help stakeholders to protect and alert municipalities facing uncertainties and changes in karst flash floods

NASA Astrophysics Data System (ADS)

Borrell Estupina, V.; Raynaud, F.; Bourgeois, N.; Kong-A-Siou, L.; Collet, L.; Haziza, E.; Servat, E.

2015-06-01

Flash floods are often responsible for many deaths and involve many material damages. Regarding Mediterranean karst aquifers, the complexity of connections, between surface and groundwater, as well as weather non-stationarity patterns, increase difficulties in understanding the basins behaviour and thus warning and protecting people. Furthermore, given the recent changes in land use and extreme rainfall events, knowledge of the past floods is no longer sufficient to manage flood risks. Therefore the worst realistic flood that could occur should be considered. Physical and processes-based hydrological models are considered among the best ways to forecast floods under diverse conditions. However, they rarely match with the stakeholders' needs. In fact, the forecasting services, the municipalities, and the civil security have difficulties in running and interpreting data-consuming models in real-time, above all if data are uncertain or non-existent. To face these social and technical difficulties and help stakeholders, this study develops two operational tools derived from these models. These tools aim at planning real-time decisions given little, changing, and uncertain information available, which are: (i) a hydrological graphical tool (abacus) to estimate flood peak discharge from the karst past state and the forecasted but uncertain intense rainfall; (ii) a GIS-based method (MARE) to estimate the potential flooded pathways and areas, accounting for runoff and karst contributions and considering land use changes. Then, outputs of these tools are confronted to past and recent floods and municipalities observations, and the impacts of uncertainties and changes on planning decisions are discussed. The use of these tools on the recent 2014 events demonstrated their reliability and interest for stakeholders. This study was realized on French Mediterranean basins, in close collaboration with the Flood Forecasting Services (SPC Med-Ouest, SCHAPI, municipalities).

Stochastic Order Redshift Technique (SORT): a simple, efficient and robust method to improve cosmological redshift measurements

NASA Astrophysics Data System (ADS)

Tejos, Nicolas; Rodríguez-Puebla, Aldo; Primack, Joel R.

2018-01-01

We present a simple, efficient and robust approach to improve cosmological redshift measurements. The method is based on the presence of a reference sample for which a precise redshift number distribution (dN/dz) can be obtained for different pencil-beam-like sub-volumes within the original survey. For each sub-volume we then impose that: (i) the redshift number distribution of the uncertain redshift measurements matches the reference dN/dz corrected by their selection functions and (ii) the rank order in redshift of the original ensemble of uncertain measurements is preserved. The latter step is motivated by the fact that random variables drawn from Gaussian probability density functions (PDFs) of different means and arbitrarily large standard deviations satisfy stochastic ordering. We then repeat this simple algorithm for multiple arbitrary pencil-beam-like overlapping sub-volumes; in this manner, each uncertain measurement has multiple (non-independent) 'recovered' redshifts which can be used to estimate a new redshift PDF. We refer to this method as the Stochastic Order Redshift Technique (SORT). We have used a state-of-the-art N-body simulation to test the performance of SORT under simple assumptions and found that it can improve the quality of cosmological redshifts in a robust and efficient manner. Particularly, SORT redshifts (zsort) are able to recover the distinctive features of the so-called 'cosmic web' and can provide unbiased measurement of the two-point correlation function on scales ≳4 h-1Mpc. Given its simplicity, we envision that a method like SORT can be incorporated into more sophisticated algorithms aimed to exploit the full potential of large extragalactic photometric surveys.

Reducing regional drought vulnerabilities and multi-city robustness conflicts using many-objective optimization under deep uncertainty

NASA Astrophysics Data System (ADS)

Trindade, B. C.; Reed, P. M.; Herman, J. D.; Zeff, H. B.; Characklis, G. W.

2017-06-01

Emerging water scarcity concerns in many urban regions are associated with several deeply uncertain factors, including rapid population growth, limited coordination across adjacent municipalities and the increasing risks for sustained regional droughts. Managing these uncertainties will require that regional water utilities identify coordinated, scarcity-mitigating strategies that trigger the appropriate actions needed to avoid water shortages and financial instabilities. This research focuses on the Research Triangle area of North Carolina, seeking to engage the water utilities within Raleigh, Durham, Cary and Chapel Hill in cooperative and robust regional water portfolio planning. Prior analysis of this region through the year 2025 has identified significant regional vulnerabilities to volumetric shortfalls and financial losses. Moreover, efforts to maximize the individual robustness of any of the mentioned utilities also have the potential to strongly degrade the robustness of the others. This research advances a multi-stakeholder Many-Objective Robust Decision Making (MORDM) framework to better account for deeply uncertain factors when identifying cooperative drought management strategies. Our results show that appropriately designing adaptive risk-of-failure action triggers required stressing them with a comprehensive sample of deeply uncertain factors in the computational search phase of MORDM. Search under the new ensemble of states-of-the-world is shown to fundamentally change perceived performance tradeoffs and substantially improve the robustness of individual utilities as well as the overall region to water scarcity. Search under deep uncertainty enhanced the discovery of how cooperative water transfers, financial risk mitigation tools, and coordinated regional demand management must be employed jointly to improve regional robustness and decrease robustness conflicts between the utilities. Insights from this work have general merit for regions where adjacent municipalities can benefit from cooperative regional water portfolio planning.

Adaptive neural output-feedback control for nonstrict-feedback time-delay fractional-order systems with output constraints and actuator nonlinearities.

PubMed

Zouari, Farouk; Ibeas, Asier; Boulkroune, Abdesselem; Cao, Jinde; Mehdi Arefi, Mohammad

2018-06-01

This study addresses the issue of the adaptive output tracking control for a category of uncertain nonstrict-feedback delayed incommensurate fractional-order systems in the presence of nonaffine structures, unmeasured pseudo-states, unknown control directions, unknown actuator nonlinearities and output constraints. Firstly, the mean value theorem and the Gaussian error function are introduced to eliminate the difficulties that arise from the nonaffine structures and the unknown actuator nonlinearities, respectively. Secondly, the immeasurable tracking error variables are suitably estimated by constructing a fractional-order linear observer. Thirdly, the neural network, the Razumikhin Lemma, the variable separation approach, and the smooth Nussbaum-type function are used to deal with the uncertain nonlinear dynamics, the unknown time-varying delays, the nonstrict feedback and the unknown control directions, respectively. Fourthly, asymmetric barrier Lyapunov functions are employed to overcome the violation of the output constraints and to tune online the parameters of the adaptive neural controller. Through rigorous analysis, it is proved that the boundedness of all variables in the closed-loop system and the semi global asymptotic tracking are ensured without transgression of the constraints. The principal contributions of this study can be summarized as follows: (1) based on Caputo's definitions and new lemmas, methods concerning the controllability, observability and stability analysis of integer-order systems are extended to fractional-order ones, (2) the output tracking objective for a relatively large class of uncertain systems is achieved with a simple controller and less tuning parameters. Finally, computer-simulation studies from the robotic field are given to demonstrate the effectiveness of the proposed controller. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multi-Agent Many-Objective Robust Decision Making: Supporting Cooperative Regional Water Portfolio Planning in the Eastern United States

NASA Astrophysics Data System (ADS)

Herman, J. D.; Zeff, H. B.; Reed, P. M.; Characklis, G. W.

2013-12-01

In the Eastern United States, water infrastructure and institutional frameworks have evolved in a historically water-rich environment. However, large regional droughts over the past decade combined with continuing population growth have marked a transition to a state of water scarcity, for which current planning paradigms are ill-suited. Significant opportunities exist to improve the efficiency of water infrastructure via regional coordination, namely, regional 'portfolios' of water-related assets such as reservoirs, conveyance, conservation measures, and transfer agreements. Regional coordination offers the potential to improve reliability, cost, and environmental impact in the expected future state of the world, and, with informed planning, to improve robustness to future uncertainty. In support of this challenge, this study advances a multi-agent many-objective robust decision making (multi-agent MORDM) framework that blends novel computational search and uncertainty analysis tools to discover flexible, robust regional portfolios. Our multi-agent MORDM framework is demonstrated for four water utilities in the Research Triangle region of North Carolina, USA. The utilities supply nearly two million customers and have the ability to interact with one another via transfer agreements and shared infrastructure. We show that strategies for this region which are Pareto-optimal in the expected future state of the world remain vulnerable to performance degradation under alternative scenarios of deeply uncertain hydrologic and economic factors. We then apply the Patient Rule Induction Method (PRIM) to identify which of these uncertain factors drives the individual and collective vulnerabilities for the four cooperating utilities. Our results indicate that clear multi-agent tradeoffs emerge for attaining robustness across the utilities. Furthermore, the key factor identified for improving the robustness of the region's water supply is cooperative demand reduction. This type of approach is critically important given the risks and challenges posed by rising supply development costs, limits on new infrastructure, growing water demands and the underlying uncertainties associated with climate change. The proposed framework serves as a planning template for other historically water-rich regions which must now confront the reality of impending water scarcity.

Initializing carbon cycle predictions from the Community Land Model by assimilating global biomass observations

NASA Astrophysics Data System (ADS)

Fox, A. M.; Hoar, T. J.; Smith, W. K.; Moore, D. J.

2017-12-01

The locations and longevity of terrestrial carbon sinks remain uncertain, however it is clear that in order to predict long-term climate changes the role of the biosphere in surface energy and carbon balance must be understood and incorporated into earth system models (ESMs). Aboveground biomass, the amount of carbon stored in vegetation, is a key component of the terrestrial carbon cycle, representing the balance of uptake through gross primary productivity (GPP), losses from respiration, senescence and mortality over hundreds of years. The best predictions of current and future land-atmosphere fluxes are likely from the integration of process-based knowledge contained in models and information from observations of changes in carbon stocks using data assimilation (DA). By exploiting long times series, it is possible to accurately detect variability and change in carbon cycle dynamics through monitoring ecosystem states, for example biomass derived from vegetation optical depth (VOD), and use this information to initialize models before making predictions. To make maximum use of information about the current state of global ecosystems when using models we have developed a system that combines the Community Land Model (CLM) with the Data Assimilation Research Testbed (DART), a community tool for ensemble DA. This DA system is highly innovative in its complexity, completeness and capabilities. Here we described a series of activities, using both Observation System Simulation Experiments (OSSEs) and real observations, that have allowed us to quantify the potential impact of assimilating VOD data into CLM-DART on future land-atmosphere fluxes. VOD data are particularly suitable to use in this activity due to their long temporal coverage and appropriate scale when combined with CLM, but their absolute values rely on many assumptions. Therefore, we have had to assess the implications of the VOD retrieval algorithms, with an emphasis on detecting uncertainty due to assumptions and inputs in the algorithms that are incompatible with those encoded within CLM. It is probable that VOD describes changes in biomass more accurately than absolute values, so in additional to sequential assimilation of observations, we have tested alternative filter algorithms, and assimilating VOD anomalies.

"Improving Native American elder access to and use of health care through effective health system navigation".

PubMed

Willging, Cathleen E; Sommerfeld, David H; Jaramillo, Elise Trott; Lujan, Erik; Bly, Roxane Spruce; Debenport, Erin K; Verney, Steven P; Lujan, Ron

2018-06-18

Public insurance reforms of the past two decades have failed to substantively address the healthcare needs of American Indians in general, let alone the particular needs of American Indian elders, ages 55 years and older. Historically, this population is more likely to be uninsured and to suffer from greater morbidities, poorer health outcomes and quality of life, and lower life expectancies compared to all other United States aging populations, representing a neglected group within the healthcare system. Despite the pervasive belief that the Indian Health Service will address all their health-related needs, American Indian elders are negatively affected by gaps in insurance and lack of access to health care. While the 2010 Patient Protection and Affordable Care Act included provisions to ameliorate disparities for American Indians, its future is uncertain. In this context, American Indian elders with variable health literacy must navigate a complex and unstable healthcare system, regardless of where they seek care. This community-driven study features a mixed-method, participatory design to examine help-seeking behavior and healthcare experiences of American Indian elders in New Mexico, in order to develop and evaluate a tailored intervention to enhance knowledge of, access to, and use of insurance and available services to reduce healthcare disparities. This study includes qualitative and quantitative interviews combined with concept mapping and focus groups with American Indian elders and other key stakeholders. The information gathered will generate new practical knowledge, grounded in actual perspectives of American Indian elders and other relevant stakeholders, to improve healthcare practices and policies for a population that has been largely excluded from national and state discussions of healthcare reform. Study data will inform development and evaluation of culturally tailored programming to enhance understanding and facilitate negotiation of the changing landscape of health care by American Indian elders. This work will fill a gap in research on public insurance initiatives, which do not typically focus on this population, and will offer a replicable model for enhancing the effects of such initiatives on other underserved groups affected by healthcare inequities. This protocol does not include the collection of health outcome data. Clinicaltrials.gov, NCT03550404 . Registered June 6, 2018.

Robust control for uncertain structures

NASA Technical Reports Server (NTRS)

Douglas, Joel; Athans, Michael

1991-01-01

Viewgraphs on robust control for uncertain structures are presented. Topics covered include: robust linear quadratic regulator (RLQR) formulas; mismatched LQR design; RLQR design; interpretations of RLQR design; disturbance rejection; and performance comparisons: RLQR vs. mismatched LQR.

Cutting Force Predication Based on Integration of Symmetric Fuzzy Number and Finite Element Method

PubMed Central

Wang, Zhanli; Hu, Yanjuan; Wang, Yao; Dong, Chao; Pang, Zaixiang

2014-01-01

In the process of turning, pointing at the uncertain phenomenon of cutting which is caused by the disturbance of random factors, for determining the uncertain scope of cutting force, the integrated symmetric fuzzy number and the finite element method (FEM) are used in the prediction of cutting force. The method used symmetric fuzzy number to establish fuzzy function between cutting force and three factors and obtained the uncertain interval of cutting force by linear programming. At the same time, the change curve of cutting force with time was directly simulated by using thermal-mechanical coupling FEM; also the nonuniform stress field and temperature distribution of workpiece, tool, and chip under the action of thermal-mechanical coupling were simulated. The experimental result shows that the method is effective for the uncertain prediction of cutting force. PMID:24790556

Angiogenic factors and pregnant woman with new onset seizures.

PubMed

Quant, Hayley; Arden, Deborah; Takoudes, Tamara; Rana, Sarosh

2012-01-01

In patients with new onset seizures during pregnancy, it can be challenging to differentiate between eclampsia and other etiologies. Soluble fms-like tyrosine kinase (sFlt1) is an antiangiogenic protein that is elevated in preeclampsia and eclampsia. A multiparous woman presented at 22 weeks gestation with seizures. The initial presentation was highly suspicious for eclampsia, but blood pressure and laboratory data were equivocal. Further investigation suggested primary seizure disorder. Serum sFlt1 was normal for gestational age, supporting the exclusion of eclampsia. History, physical exam, and traditional laboratory data are the mainstays of eclampsia diagnosis; however, sFlt1 may help clinicians when the diagnosis is uncertain at preterm gestational ages.

Review of Reliability-Based Design Optimization Approach and Its Integration with Bayesian Method

NASA Astrophysics Data System (ADS)

Zhang, Xiangnan

2018-03-01

A lot of uncertain factors lie in practical engineering, such as external load environment, material property, geometrical shape, initial condition, boundary condition, etc. Reliability method measures the structural safety condition and determine the optimal design parameter combination based on the probabilistic theory. Reliability-based design optimization (RBDO) is the most commonly used approach to minimize the structural cost or other performance under uncertainty variables which combines the reliability theory and optimization. However, it cannot handle the various incomplete information. The Bayesian approach is utilized to incorporate this kind of incomplete information in its uncertainty quantification. In this paper, the RBDO approach and its integration with Bayesian method are introduced.

What motivates researchers in times of economic uncertainty.

NASA Technical Reports Server (NTRS)

Bucher, G. C.; Reece, J. E.

1972-01-01

Results of a study initiated late in 1970 to obtain both a measure of on-and-around-the-job factors which were 'motivating' to engineers and scientists, and to obtain an indication of how the relative importance of these factors changes as a result of the uncertain economic environment. A questionnaire, 'The Jackman Job Satisfaction Schedule,' was used to satisfy the needs of the study. It is concluded that managers can enhance the feeling of motivation by making individual job assignments interesting and challenging, by formulating significant milestones and end points into job content, and by assigning ample rewards with corresponding responsibility. In times of economic uncertainty increased emphasis should be given to security-related aspects of employment.

Physicians' Religious Topic Avoidance during Clinical Interactions.

PubMed

Villagran, Melinda M; MacArthur, Brenda L; Lee, Lauren E; Ledford, Christy J W; Canzona, Mollie R

2017-05-08

Religious and spiritual (R/S) conversations at the end-of-life function to help patients and their families find comfort in difficult circumstances. Physicians who feel uncertain about how to discuss topics related to religious beliefs may seek to avoid R/S conversations with their patients. This study utilized a two-group objective structured clinical examination with a standardized patient to explore differences in physicians' use of R/S topic avoidance tactics during a clinical interaction. Results indicated that physicians used more topic avoidance tactics in response to patients' R/S inquiries than patients' R/S disclosures; however, the use of topic avoidance tactics did not eliminate the need to engage in patient-initiated R/S interactions.

Moving the science data quality dialogue forward

NASA Astrophysics Data System (ADS)

Robinson, Erin; Meyer, Carol B.; Lenhardt, W. Christopher

2012-05-01

Federation of Earth Science Information Partners Summer 2011 Meeting; Santa Fe, New Mexico, 12-15 July 2011 Scientific data quality is important to scientists, archivists, decision makers, and the public. Uncertain quality costs valuable research dollars and has impacts beyond the initial science. The Federation of Earth Science Information Partners (ESIP) is a consortium of Earth science data and technology professionals spanning the government (NASA, National Oceanic and Atmospheric Administration, U.S. Environmental Protection Agency, U.S. Geological Survey (USGS), National Science Foundation), academia, and private sectors (both commercial and nonprofit). The organization is dedicated to transforming research data and information into useful and usable data and information products for decision makers, policy makers, and the public.

Physicians’ Religious Topic Avoidance during Clinical Interactions

PubMed Central

Villagran, Melinda M.; MacArthur, Brenda L.; Lee, Lauren E.; Ledford, Christy J. W.; Canzona, Mollie R.

2017-01-01

Religious and spiritual (R/S) conversations at the end-of-life function to help patients and their families find comfort in difficult circumstances. Physicians who feel uncertain about how to discuss topics related to religious beliefs may seek to avoid R/S conversations with their patients. This study utilized a two-group objective structured clinical examination with a standardized patient to explore differences in physicians’ use of R/S topic avoidance tactics during a clinical interaction. Results indicated that physicians used more topic avoidance tactics in response to patients’ R/S inquiries than patients’ R/S disclosures; however, the use of topic avoidance tactics did not eliminate the need to engage in patient-initiated R/S interactions. PMID:28481290

Pulmonary Paragonimiasis: The Detection of a Worm Migration Track as a Diagnostic Clue for Uncertain Eosinophilic Pleural Effusion.

PubMed

Akaba, Tomohiro; Takeyama, Kiyoshi; Toriyama, Midori; Kubo, Ayako; Mizobuchi, Rie; Yamada, Takeshi; Tagaya, Etsuko; Kondo, Mitsuko; Sakai, Shuji; Tamaoki, Jun

2016-01-01

A 38-year-old woman with sustained right chest pain was referred to our hospital. She showed pleural effusion and peripheral blood eosinophilia. Thoracentesis revealed eosinophilic pleural effusion in which the smear, culture and cytological examinations were all negative. Although she had no notable dietary history, chest CT revealed linear opacities, which suggested the migration tracks of paragonimiasis. The diagnosis was confirmed using enzyme-linked immunosorbent assays, which showed elevated Paragonimus westermani and Paragonimus miyazakii antibody levels. After the initiation of praziquantel therapy, all clinical findings were promptly improved. The detection of a migration track may therefore be useful in the diagnosis of paragonimiasis.

Herpes simplex virus type 2 recurrent meningitis (Mollaret's meningitis): a consideration for the recurrent pathogenesis.

PubMed

Sato, Rumi; Ayabe, Mitsuyoshi; Shoji, Hiroshi; Ichiyama, Takashi; Saito, Yumiko; Hondo, Ryo; Eizuru, Yoshito

2005-11-01

We report a 44-year-old Japanese woman with herpes simplex virus (HSV) type 2 recurrent meningitis (Mollaret's meningitis). The diagnosis was confirmed by nested polymerase chain reaction in her cerebrospinal fluid, but the patient's conventional HSV antibodies by complement fixation, neutralizing test or enzyme immunoassay showed low titres with low lymphoproliferative response. Several similar cases are discussed. Although the reason for the recurrent pathogenesis is uncertain, our report suggests that the low immune response including immune evasion may be involved in the pathogenesis of HSV type 2 recurrent meningitis. For this patient, long-term suppressive and patient-initiated therapies were conducted to prevent the recurrence of meningitis.

Opinion & Special Articles: A guide from fellowship to faculty

PubMed Central

2012-01-01

The role of the physician scientist in biomedical research is increasingly threatened. Despite a clear role in clinical advances in translational medicine, the percentage of physicians engaged in research has steadily declined. Several programmatic efforts have been initiated to address this problem by providing time and financial resources to the motivated resident or fellow. However, this decline in physician scientists is due not only to a lack of time and resources but also a reflection of the uncertain path in moving from residency or postdoctoral training toward junior faculty. This article is a practical guide to the milestones and barriers to successful faculty achievement after residency or fellowship training. PMID:23033506

Opinion & special articles: a guide from fellowship to faculty: Nietzsche and the academic neurologist.

PubMed

Carmichael, S Thomas

2012-10-02

The role of the physician scientist in biomedical research is increasingly threatened. Despite a clear role in clinical advances in translational medicine, the percentage of physicians engaged in research has steadily declined. Several programmatic efforts have been initiated to address this problem by providing time and financial resources to the motivated resident or fellow. However, this decline in physician scientists is due not only to a lack of time and resources but also a reflection of the uncertain path in moving from residency or postdoctoral training toward junior faculty. This article is a practical guide to the milestones and barriers to successful faculty achievement after residency or fellowship training.

Engineers on the Twin Rivers: A History of the Nashville District Corps of Engineers United States Army

DTIC Science & Technology

1978-01-01

Kentucky, near the present site of Barkley Dam. The schooners Fanny and Maria and Con- cordia were built by James Winchester, William Cage, James Cage...Cumber- land Valley. Many farmers hoped to abandon the uncertain business of farm- ing and get rich by feeding the produc- tive worms. Acres were planted ...frequently attempt to capture the entire plant , careless of any damage inflicted on the lock masonry, lock gates, lever of sluices, &c." To curb this "in