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Sample records for based sequential dynamic

  1. Sequential memory: Binding dynamics

    NASA Astrophysics Data System (ADS)

    Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

    2015-10-01

    Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories—episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities.

  2. Sequential memory: Binding dynamics.

    PubMed

    Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

    2015-10-01

    Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories-episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities. PMID:26520084

  3. Dynamic Compressed HRRP Generation for Random Stepped-Frequency Radar Based on Complex-Valued Fast Sequential Homotopy

    PubMed Central

    You, Peng; Liu, Zhen; Wang, Hongqiang; Wei, Xizhang; Li, Xiang

    2014-01-01

    Compressed sensing has been applied to achieve high resolution range profiles (HRRPs) using a stepped-frequency radar. In this new scheme, much fewer pulses are required to recover the target's strong scattering centers, which can greatly reduce the coherent processing interval (CPI) and improve the anti-jamming capability. For practical applications, however, the required number of pulses is difficult to determine in advance and any reduction of the transmitted pulses is attractive. In this paper, a dynamic compressed sensing strategy for HRRP generation is proposed, in which the estimated HRRP is updated with sequentially transmitted and received pulses until the proper stopping rules are satisfied. To efficiently implement the sequential update, a complex-valued fast sequential homotopy (CV-FSH) algorithm is developed based on group sparse recovery. This algorithm performs as an efficient recursive procedure of sparse recovery, thus avoiding solving a new optimization problem from scratch. Furthermore, the proper stopping rules are presented according to the special characteristics of HRRP. Therefore, the optimal number of pulses required in each CPI can be sought adapting to the echo signal. The results using simulated and real data show the effectiveness of the proposed approach and demonstrate that the established dynamic strategy is more suitable for uncooperative targets. PMID:24815679

  4. A physiology-based inverse dynamic analysis of human gait using sequential convex programming: a comparative study.

    PubMed

    De Groote, F; Demeulenaere, B; Swevers, J; De Schutter, J; Jonkers, I

    2012-01-01

    This paper presents an enhanced version of the previously proposed physiological inverse approach (PIA) to calculate musculotendon (MT) forces and evaluates the proposed methodology in a comparative study. PIA combines an inverse dynamic analysis with an optimisation approach that imposes muscle physiology and optimises performance over the entire motion. To solve the resulting large-scale, nonlinear optimisation problem, we neglected muscle fibre contraction speed and an approximate quadratic optimisation problem (PIA-QP) was formulated. Conversely, the enhanced version of PIA proposed in this paper takes into account muscle fibre contraction speed. The optimisation problem is solved using a sequential convex programing procedure (PIA-SCP). The comparative study includes PIA-SCP, PIA-QP and two commonly used approaches from the literature: static optimisation (SO) and computed muscle control (CMC). SO and CMC make simplifying assumptions to limit the computational time. Both methods minimise an instantaneous performance criterion. Furthermore, SO does not impose muscle physiology. All methods are applied to a gait cycle of six control subjects. The relative root mean square error averaged over all subjects, ε(RMS), between the joint torques simulated from the optimised activations and the joint torques obtained from the inverse dynamic analysis was about twice as large for SO (ε(RMS) = 86) as compared with CMC (ε(RMS) = 39) and PIA-SCP (ε(RMS) = 50). ε(RMS) was at least twice as large for PIA-QP (ε(RMS) = 197) than for all other methods. As compared with CMC, muscle activation patterns predicted by PIA-SCP better agree with experimental electromyography (EMG). This study shows that imposing muscle physiology as well as globally optimising performance is important to accurately calculate MT forces underlying gait. PMID:21878002

  5. Sequential dynamical systems with threshold functions.

    SciTech Connect

    Barrett, C. L.; Hunt, H. B.; Marathe, M. V.; Ravi, S. S.; Rosenkrantz, D. J.; Stearns, R. E.

    2001-01-01

    A sequential dynamical system (SDS) (see [BH+01] and the references therein) consists of an undirected graph G(V,E) where each node {nu} {epsilon} V is associated with a Boolean state (s{sub {nu}}) and a symmetric Boolean function f{sub {nu}} (called the local transition function at {nu}). The inputs to f{sub {nu}} are s{sub {nu}} and the states of all the nodes adjacent to {nu}. In each step of the SDS, the nodes update their state values using their local transition functions in the order specified by a given permutation {pi} of the nodes. A configuration of the SDS is an n-tuple (b{sub 1}, b{sub 2}...,b{sub n}) where n = |V| and b{sub i} {epsilon} {l_brace}0,1{r_brace} is the state value of node {nu}{sub i}. The system starts in a specified initial configuration and each step of the SDS produces a (possibly new) configuration.

  6. Sequential composition of dynamically dexterous robot behaviors

    SciTech Connect

    Burridge, R.R.; Rizzi, A.A.; Koditschek, D.E.

    1999-06-01

    The authors report on efforts to develop a sequential robot controller-composition technique in the context of dexterous batting maneuvers. A robot with a flat paddle is required to strike repeatedly at a thrown ball until the ball is brought to rest on the paddle at a specified location. The robot`s reachable workspace is blocked by an obstacle that disconnects the free space formed when the ball and paddle remain in contact, forcing the machine to let go for a time to bring the ball to the desired state. The controller compositions the authors create guarantee that a ball introduced in the safe workspace remains there and is ultimately brought to the goal. They report on experimental results from an implementation of these formal composition methods, and present descriptive statistics characterizing the experiments.

  7. Structural Drift: The Population Dynamics of Sequential Learning

    PubMed Central

    Crutchfield, James P.; Whalen, Sean

    2012-01-01

    We introduce a theory of sequential causal inference in which learners in a chain estimate a structural model from their upstream “teacher” and then pass samples from the model to their downstream “student”. It extends the population dynamics of genetic drift, recasting Kimura's selectively neutral theory as a special case of a generalized drift process using structured populations with memory. We examine the diffusion and fixation properties of several drift processes and propose applications to learning, inference, and evolution. We also demonstrate how the organization of drift process space controls fidelity, facilitates innovations, and leads to information loss in sequential learning with and without memory. PMID:22685387

  8. Sequential Bayesian Detection: A Model-Based Approach

    SciTech Connect

    Sullivan, E J; Candy, J V

    2007-08-13

    Sequential detection theory has been known for a long time evolving in the late 1940's by Wald and followed by Middleton's classic exposition in the 1960's coupled with the concurrent enabling technology of digital computer systems and the development of sequential processors. Its development, when coupled to modern sequential model-based processors, offers a reasonable way to attack physics-based problems. In this chapter, the fundamentals of the sequential detection are reviewed from the Neyman-Pearson theoretical perspective and formulated for both linear and nonlinear (approximate) Gauss-Markov, state-space representations. We review the development of modern sequential detectors and incorporate the sequential model-based processors as an integral part of their solution. Motivated by a wealth of physics-based detection problems, we show how both linear and nonlinear processors can seamlessly be embedded into the sequential detection framework to provide a powerful approach to solving non-stationary detection problems.

  9. Sequential Bayesian Detection: A Model-Based Approach

    SciTech Connect

    Candy, J V

    2008-12-08

    Sequential detection theory has been known for a long time evolving in the late 1940's by Wald and followed by Middleton's classic exposition in the 1960's coupled with the concurrent enabling technology of digital computer systems and the development of sequential processors. Its development, when coupled to modern sequential model-based processors, offers a reasonable way to attack physics-based problems. In this chapter, the fundamentals of the sequential detection are reviewed from the Neyman-Pearson theoretical perspective and formulated for both linear and nonlinear (approximate) Gauss-Markov, state-space representations. We review the development of modern sequential detectors and incorporate the sequential model-based processors as an integral part of their solution. Motivated by a wealth of physics-based detection problems, we show how both linear and nonlinear processors can seamlessly be embedded into the sequential detection framework to provide a powerful approach to solving non-stationary detection problems.

  10. A mathematical programming approach for sequential clustering of dynamic networks

    NASA Astrophysics Data System (ADS)

    Silva, Jonathan C.; Bennett, Laura; Papageorgiou, Lazaros G.; Tsoka, Sophia

    2016-02-01

    A common analysis performed on dynamic networks is community structure detection, a challenging problem that aims to track the temporal evolution of network modules. An emerging area in this field is evolutionary clustering, where the community structure of a network snapshot is identified by taking into account both its current state as well as previous time points. Based on this concept, we have developed a mixed integer non-linear programming (MINLP) model, SeqMod, that sequentially clusters each snapshot of a dynamic network. The modularity metric is used to determine the quality of community structure of the current snapshot and the historical cost is accounted for by optimising the number of node pairs co-clustered at the previous time point that remain so in the current snapshot partition. Our method is tested on social networks of interactions among high school students, college students and members of the Brazilian Congress. We show that, for an adequate parameter setting, our algorithm detects the classes that these students belong more accurately than partitioning each time step individually or by partitioning the aggregated snapshots. Our method also detects drastic discontinuities in interaction patterns across network snapshots. Finally, we present comparative results with similar community detection methods for time-dependent networks from the literature. Overall, we illustrate the applicability of mathematical programming as a flexible, adaptable and systematic approach for these community detection problems. Contribution to the Topical Issue "Temporal Network Theory and Applications", edited by Petter Holme.

  11. Sequential reconstruction of driving-forces from nonlinear nonstationary dynamics

    NASA Astrophysics Data System (ADS)

    Güntürkün, Ulaş

    2010-07-01

    This paper describes a functional analysis-based method for the estimation of driving-forces from nonlinear dynamic systems. The driving-forces account for the perturbation inputs induced by the external environment or the secular variations in the internal variables of the system. The proposed algorithm is applicable to the problems for which there is too little or no prior knowledge to build a rigorous mathematical model of the unknown dynamics. We derive the estimator conditioned on the differentiability of the unknown system’s mapping, and smoothness of the driving-force. The proposed algorithm is an adaptive sequential realization of the blind prediction error method, where the basic idea is to predict the observables, and retrieve the driving-force from the prediction error. Our realization of this idea is embodied by predicting the observables one-step into the future using a bank of echo state networks (ESN) in an online fashion, and then extracting the raw estimates from the prediction error and smoothing these estimates in two adaptive filtering stages. The adaptive nature of the algorithm enables to retrieve both slowly and rapidly varying driving-forces accurately, which are illustrated by simulations. Logistic and Moran-Ricker maps are studied in controlled experiments, exemplifying chaotic state and stochastic measurement models. The algorithm is also applied to the estimation of a driving-force from another nonlinear dynamic system that is stochastic in both state and measurement equations. The results are judged by the posterior Cramer-Rao lower bounds. The method is finally put into test on a real-world application; extracting sun’s magnetic flux from the sunspot time series.

  12. Constraint-based evaluation of sequential procedures

    NASA Technical Reports Server (NTRS)

    Barry, Matthew R.

    1990-01-01

    Constraining the operation of an agent requires knowledge of the restrictions to physical and temporal capabilities of that agent, as well as an inherent understanding of the desires being processed by that agent. Usually a set of constraints are available that must be adhered to in order to foster safe operations. In the worst case, violation of a constraint may be cause to terminate operation. If the agent is carrying out a plan, then a method for predicting the agent's desires, and therefore possible constraint violations, is required. The conceptualization of constraint-based reasoning used herein assumes that a system knows how to select a constraint for application as well as how to apply that constraint once it is selected. The application of constraint-based reasoning for evaluating certain kinds of plans known as sequential procedures is discussed. By decomposing these plans, it is possible to apply context dependent constraints in production system fashion without incorporating knowledge of the original planning process.

  13. Bursts and Heavy Tails in Temporal and Sequential Dynamics of Foraging Decisions

    PubMed Central

    Jung, Kanghoon; Jang, Hyeran; Kralik, Jerald D.; Jeong, Jaeseung

    2014-01-01

    A fundamental understanding of behavior requires predicting when and what an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. In the current study, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding when choices were made, we found bursts of rapidly occurring actions, separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding what was chosen, we found sequential dynamics in affective choices characterized by two key features: (a) a highly biased choice distribution; and (b) preferential attachment, in which the animals were more likely to choose what they had previously chosen. To capture the temporal dynamics, we propose a dual-state model consisting of active and inactive states. We also introduce a satiation-attainment process for bursty activity, and a non-homogeneous Poisson process for longer inactivity between bursts. For the sequential dynamics, we propose a dual-control model consisting of goal-directed and habit systems, based on outcome valuation and choice history, respectively. This study provides insights into how the bursty nature of behavior emerges from the interaction of different underlying systems, leading to heavy tails in the distribution of behavior over time and choices. PMID:25122498

  14. Sequential activation of metabolic pathways: a dynamic optimization approach.

    PubMed

    Oyarzún, Diego A; Ingalls, Brian P; Middleton, Richard H; Kalamatianos, Dimitrios

    2009-11-01

    The regulation of cellular metabolism facilitates robust cellular operation in the face of changing external conditions. The cellular response to this varying environment may include the activation or inactivation of appropriate metabolic pathways. Experimental and numerical observations of sequential timing in pathway activation have been reported in the literature. It has been argued that such patterns can be rationalized by means of an underlying optimal metabolic design. In this paper we pose a dynamic optimization problem that accounts for time-resource minimization in pathway activation under constrained total enzyme abundance. The optimized variables are time-dependent enzyme concentrations that drive the pathway to a steady state characterized by a prescribed metabolic flux. The problem formulation addresses unbranched pathways with irreversible kinetics. Neither specific reaction kinetics nor fixed pathway length are assumed.In the optimal solution, each enzyme follows a switching profile between zero and maximum concentration, following a temporal sequence that matches the pathway topology. This result provides an analytic justification of the sequential activation previously described in the literature. In contrast with the existent numerical approaches, the activation sequence is proven to be optimal for a generic class of monomolecular kinetics. This class includes, but is not limited to, Mass Action, Michaelis-Menten, Hill, and some Power-law models. This suggests that sequential enzyme expression may be a common feature of metabolic regulation, as it is a robust property of optimal pathway activation. PMID:19412635

  15. Relating the sequential dynamics of excitatory neural networks to synaptic cellular automata.

    PubMed

    Nekorkin, V I; Dmitrichev, A S; Kasatkin, D V; Afraimovich, V S

    2011-12-01

    We have developed a new approach for the description of sequential dynamics of excitatory neural networks. Our approach is based on the dynamics of synapses possessing the short-term plasticity property. We suggest a model of such synapses in the form of a second-order system of nonlinear ODEs. In the framework of the model two types of responses are realized-the fast and the slow ones. Under some relations between their timescales a cellular automaton (CA) on the graph of connections is constructed. Such a CA has only a finite number of attractors and all of them are periodic orbits. The attractors of the CA determine the regimes of sequential dynamics of the original neural network, i.e., itineraries along the network and the times of successive firing of neurons in the form of bunches of spikes. We illustrate our approach on the example of a Morris-Lecar neural network. PMID:22225361

  16. Dynamic stability of sequential stimulus representations in adapting neuronal networks

    PubMed Central

    Duarte, Renato C. F.; Morrison, Abigail

    2014-01-01

    The ability to acquire and maintain appropriate representations of time-varying, sequential stimulus events is a fundamental feature of neocortical circuits and a necessary first step toward more specialized information processing. The dynamical properties of such representations depend on the current state of the circuit, which is determined primarily by the ongoing, internally generated activity, setting the ground state from which input-specific transformations emerge. Here, we begin by demonstrating that timing-dependent synaptic plasticity mechanisms have an important role to play in the active maintenance of an ongoing dynamics characterized by asynchronous and irregular firing, closely resembling cortical activity in vivo. Incoming stimuli, acting as perturbations of the local balance of excitation and inhibition, require fast adaptive responses to prevent the development of unstable activity regimes, such as those characterized by a high degree of population-wide synchrony. We establish a link between such pathological network activity, which is circumvented by the action of plasticity, and a reduced computational capacity. Additionally, we demonstrate that the action of plasticity shapes and stabilizes the transient network states exhibited in the presence of sequentially presented stimulus events, allowing the development of adequate and discernible stimulus representations. The main feature responsible for the increased discriminability of stimulus-driven population responses in plastic networks is shown to be the decorrelating action of inhibitory plasticity and the consequent maintenance of the asynchronous irregular dynamic regime both for ongoing activity and stimulus-driven responses, whereas excitatory plasticity is shown to play only a marginal role. PMID:25374534

  17. Transcriptome dynamics of Arabidopsis during sequential biotic and abiotic stresses.

    PubMed

    Coolen, Silvia; Proietti, Silvia; Hickman, Richard; Davila Olivas, Nelson H; Huang, Ping-Ping; Van Verk, Marcel C; Van Pelt, Johan A; Wittenberg, Alexander H J; De Vos, Martin; Prins, Marcel; Van Loon, Joop J A; Aarts, Mark G M; Dicke, Marcel; Pieterse, Corné M J; Van Wees, Saskia C M

    2016-05-01

    In nature, plants have to cope with a wide range of stress conditions that often occur simultaneously or in sequence. To investigate how plants cope with multi-stress conditions, we analyzed the dynamics of whole-transcriptome profiles of Arabidopsis thaliana exposed to six sequential double stresses inflicted by combinations of: (i) infection by the necrotrophic fungus Botrytis cinerea, (ii) herbivory by chewing larvae of Pieris rapae, and (iii) drought stress. Each of these stresses induced specific expression profiles over time, in which one-third of all differentially expressed genes was shared by at least two single stresses. Of these, 394 genes were differentially expressed during all three stress conditions, albeit often in opposite directions. When two stresses were applied in sequence, plants displayed transcriptome profiles that were very similar to the second stress, irrespective of the nature of the first stress. Nevertheless, significant first-stress signatures could be identified in the sequential stress profiles. Bioinformatic analysis of the dynamics of co-expressed gene clusters highlighted specific clusters and biological processes of which the timing of activation or repression was altered by a prior stress. The first-stress signatures in second stress transcriptional profiles were remarkably often related to responses to phytohormones, strengthening the notion that hormones are global modulators of interactions between different types of stress. Because prior stresses can affect the level of tolerance against a subsequent stress (e.g. prior herbivory strongly affected resistance to B. cinerea), the first-stress signatures can provide important leads for the identification of molecular players that are decisive in the interactions between stress response pathways. PMID:26991768

  18. Sequential experimental design based generalised ANOVA

    NASA Astrophysics Data System (ADS)

    Chakraborty, Souvik; Chowdhury, Rajib

    2016-07-01

    Over the last decade, surrogate modelling technique has gained wide popularity in the field of uncertainty quantification, optimization, model exploration and sensitivity analysis. This approach relies on experimental design to generate training points and regression/interpolation for generating the surrogate. In this work, it is argued that conventional experimental design may render a surrogate model inefficient. In order to address this issue, this paper presents a novel distribution adaptive sequential experimental design (DA-SED). The proposed DA-SED has been coupled with a variant of generalised analysis of variance (G-ANOVA), developed by representing the component function using the generalised polynomial chaos expansion. Moreover, generalised analytical expressions for calculating the first two statistical moments of the response, which are utilized in predicting the probability of failure, have also been developed. The proposed approach has been utilized in predicting probability of failure of three structural mechanics problems. It is observed that the proposed approach yields accurate and computationally efficient estimate of the failure probability.

  19. Jointly Learning Multiple Sequential Dynamics for Human Action Recognition

    PubMed Central

    Liu, An-An; Su, Yu-Ting; Nie, Wei-Zhi; Yang, Zhao-Xuan

    2015-01-01

    Discovering visual dynamics during human actions is a challenging task for human action recognition. To deal with this problem, we theoretically propose the multi-task conditional random fields model and explore its application on human action recognition. For visual representation, we propose the part-induced spatiotemporal action unit sequence to represent each action sample with multiple partwise sequential feature subspaces. For model learning, we propose the multi-task conditional random fields (MTCRFs) model to discover the sequence-specific structure and the sequence-shared relationship. Specifically, the multi-chain graph structure and the corresponding probabilistic model are designed to represent the interaction among multiple part-induced action unit sequences. Moreover we propose the model learning and inference methods to discover temporal context within individual action unit sequence and the latent correlation among different body parts. Extensive experiments are implemented to demonstrate the superiority of the proposed method on two popular RGB human action datasets, KTH & TJU, and the depth dataset in MSR Daily Activity 3D. PMID:26147979

  20. Analysis problems for sequential dynamical systems and communicating state machines

    SciTech Connect

    Barrett, C. L.; Hunt, H. B.; Marathe, M. V.; Ravi, S. S.; Rosenkrantz, D. J.; Stearns, R. E.

    2001-01-01

    A simple sequential dynamical system (SDS) is a triple (G, F, {pi}), where (i) G(V, E) is an undirected graph with n nodes with each node having a 1-bit state, (ii) F = {l_brace} f{sub 1},f{sub 2},...,f{sub n}{r_brace} is a set of local transition functions with f{sub i} denoting a Boolean function associated with node Vv{sub i} and (iii) {pi} is a fixed permutation of (i.e., a total order on) the nodes in V. A single SDS transition is obtained by updating the states of the nodes in V by evaluating the function associated with each of them in the order given by {pi}. Such a (finite) SDS is a mathematical abstraction of simulation systems [BMR99, BR99]. In this paper, we characterize the computational complexity of determining several phase space properties of SDSs. The properties considered are t-REACHABILITY ('Can a given SDS starting from configuration I reach configuration B in t or fewer transitions?'), REACHABILITY('Can a given SDS starting from configuration I ever reach configuration B?') and FIXED POINT REACHABILITY ('Can a given SDS starting from configuration I ever reach configuration in which it stays for ever?'). Our main result is a sharp dichotomy between classes of SDSs whose behavior is 'easy' to predict and those whose behavior is 'hard' to predict. Specifically, we show the following. (1) The t-REACHABILITY, REACHABILITY and the FIXED POINT REACHABILITY problems for SDSs are PSPACE-complete, even when restricted to graphs of bounded bandwidth (and hence of bounded pathwidth and treewidth) and when the function associated with each node is symmetric. The result holds even for regular graphs of constant degree where all the nodes compute the same symmetric Boolean function. (2) In contrast, the t-REACHABILITYm REACHABILITY and FIXED POINT REACHABILITY problems are solvable in polynomial time for SDSs when the Boolean function associated with each node is symmetric and monotone. Two important consequences of our results are the following: (i) The

  1. STRUCTURAL ANALYSES OF FUEL CASKS SUBJECTED TO BOLT PRELOAD, INTERNAL PRESSURE AND SEQUENTIAL DYNAMIC IMPACTS

    SciTech Connect

    Wu, T

    2009-06-25

    Large fuel casks subjected to the combined loads of closure bolt tightening, internal pressure and sequential dynamic impacts present challenges when evaluating their performance in the Hypothetical Accident Conditions (HAC) specified in the Code of Federal Regulations Title 10 Part 71 (10CFR71). Testing is often limited by cost, difficulty in preparing test units and the limited availability of facilities which can carry out such tests. In the past, many casks were evaluated without testing by using simplified analytical methods. In addition, there are no realistic analyses of closure bolt stresses for HAC conditions reported in the open literature. This paper presents a numerical technique for analyzing the accumulated damages of a large fuel cask caused by the sequential loads of the closure bolt tightening and the internal pressure as well as the drop and crash dynamic loads. The bolt preload and the internal pressure are treated as quasi-static loads so that the finite element method with explicit numerical integration scheme based on the theory of wave propagation can be applied. The dynamic impacts with short durations such as the 30-foot drop and the 40-inch puncture for the hypothetical accident conditions specified in 10CFR71 are also analyzed by using the finite-element method with explicit numerical integration scheme.

  2. Predecessor and permutation existence problems for sequential dynamical systems

    SciTech Connect

    Barrett, C. L.; Hunt, H. B.; Marathe, M. V.; Rosenkrantz, D. J.; Stearns, R. E.

    2002-01-01

    A class of finite discrete dynamical systems, called Sequential Dynamical Systems (SDSs), was introduced in BMR99, BR991 as a formal model for analyzing simulation systems. An SDS S is a triple (G, F,n ),w here (i) G(V,E ) is an undirected graph with n nodes with each node having a state, (ii) F = (fi, fi, . . ., fn), with fi denoting a function associated with node ui E V and (iii) A is a permutation of (or total order on) the nodes in V, A configuration of an SDS is an n-vector ( b l, bz, . . ., bn), where bi is the value of the state of node vi. A single SDS transition from one configuration to another is obtained by updating the states of the nodes by evaluating the function associated with each of them in the order given by n. Here, we address the complexity of two basic problems and their generalizations for SDSs. Given an SDS S and a configuration C, the PREDECESSOR EXISTENCE (or PRE) problem is to determine whether there is a configuration C' such that S has a transition from C' to C. (If C has no predecessor, C is known as a garden of Eden configuration.) Our results provide separations between efficiently solvable and computationally intractable instances of the PRE problem. For example, we show that the PRE problem can be solved efficiently for SDSs with Boolean state values when the node functions are symmetric and the underlying graph is of bounded treewidth. In contrast, we show that allowing just one non-symmetric node function renders the problem NP-complete even when the underlying graph is a tree (which has a treewidth of 1). We also show that the PRE problem is efficiently solvable for SDSs whose state values are from a field and whose node functions are linear. Some of the polynomial algorithms also extend to the case where we want to find an ancestor configuration that precedes a given configuration by a logarithmic number of steps. Our results extend some of the earlier results by Sutner [Su95] and Green [@87] on the complexity of the

  3. Predecessor and permutation existence problems for sequential dynamical systems

    SciTech Connect

    Barrett, C. L.; Hunt, H. B.; Marathe, M. V.; Ravi, S. S.; Rosenkrantz, D. J.; Stearns, R. E.

    2001-01-01

    Motivated by the aim to build computer simulations for large scale systems [BMR99, BR99], we study a class of finite discrete dynamical systems called Sequential Dynamical Systems (SDSs). An SDS S is a triple (G, F, {pi}), where (i) G(V, E) is an undirected graph with n nodes with each node having a 1-bit state, (ii) F = {l_brace}f{sub 1}, f{sub 2}, ..., f{sub n}{r_brace}, with f{sub i} denoting a symmetric Boolean function associated with node v{sub i} and (iii) {pi} is a permutation of (or total order on) the nodes in V. A configuration of an SDS is a bit vector (b{sub 1}, b{sub 2}, ..., b{sub n}), where b{sub i} is the value of the state of node v{sub i}. A single SDS transition from one configuration to another is obtained by updating the states of the nodes by evaluating the function associated with each of them in the order given by {pi}. Here, we address the complexity of two problems for SDSs. Given an SDS S and a configuration C, the PREDECESSOR EXISTENCE (or PRE) problem is to determine whether there is a configuration C{prime} such that S goes from C{prime} to C in one step. We show that the PRE problem NP-complete for several simple classes of SDSs (e.g. SDSs for which the set of node functions is {l_brace}AND, OR{r_brace}, SDSs whose underlying graphs are planar). We also identify several classes of SDSs for which the PRE problem can be solved efficiently (e.g. SDSs where each node function is from {l_brace}OR, NOR{r_brace} or {l_brace}AND, NAND{r_brace} or {l_brace}XOR, XNOR{r_brace}). We also show that the PRE problem is solvable in polynomial time when the function at each node is linear or when the underlying graph G is of bounded treewidth. Many of the easiness results extend to the case where we want to find an ancestor configuration that precedes a given configuration by a polynomial number of steps. Given the underlying graph G(V, E), and two configurations C and C{prime} of an SDS S, the PERMUTATION EXISTENCE (or PME) problem is to determine

  4. DYNAMIC ANALYSIS OF HANFORD UNIRRADIATED FUEL PACKAGE SUBJECTED TO SEQUENTIAL LATERAL LOADS IN HYPOTHETICAL ACCIDENT CONDITIONS

    SciTech Connect

    Wu, T

    2008-04-30

    Large fuel casks present challenges when evaluating their performance in the Hypothetical Accident Conditions (HAC) specified in the Code of Federal Regulations Title 10 part 71 (10CFR71). Testing is often limited by cost, difficulty in preparing test units and the limited availability of facilities which can carry out such tests. In the past, many casks were evaluated without testing by using simplified analytical methods. This paper presents a numerical technique for evaluating the dynamic responses of large fuel casks subjected to sequential HAC loading. A nonlinear dynamic analysis was performed for a Hanford Unirradiated Fuel Package (HUFP) [1] to evaluate the cumulative damage after the hypothetical accident Conditions of a 30-foot lateral drop followed by a 40-inch lateral puncture as specified in 10CFR71. The structural integrity of the containment vessel is justified based on the analytical results in comparison with the stress criteria, specified in the ASME Code, Section III, Appendix F [2], for Level D service loads. The analyzed cumulative damages caused by the sequential loading of a 30-foot lateral drop and a 40-inch lateral puncture are compared with the package test data. The analytical results are in good agreement with the test results.

  5. Indications of de Sitter spacetime from classical sequential growth dynamics of causal sets

    SciTech Connect

    Ahmed, Maqbool; Rideout, David

    2010-04-15

    A large class of the dynamical laws for causal sets described by a classical process of sequential growth yields a cyclic universe, whose cycles of expansion and contraction are punctuated by single 'origin elements' of the causal set. We present evidence that the effective dynamics of the immediate future of one of these origin elements, within the context of the sequential growth dynamics, yields an initial period of de Sitter-like exponential expansion, and argue that the resulting picture has many attractive features as a model of the early universe, with the potential to solve some of the standard model puzzles without any fine-tuning.

  6. Colloid deposition in granular porous media based on random sequential adsorption mechanics

    SciTech Connect

    Johnson, P.R.; Elimelech, M.

    1995-12-01

    A theoretical model is presented for describing one-dimensional colloid transport in granular porous media. The model depicts irreversible, monolayer deposition of colloidal particles onto oppositely-charged collectors of spherical geometry. A dynamic blocking function based on random sequential adsorption (RSA) mechanics is implemented to account for the dynamic aspects of particle deposition. The RSA dynamic blocking function is modified to consider the excluded area effects arising from diffuse double-layer interactions of particles. The RSA blocking function exhibits a nonlinear power law dependence on surface coverage, in contrast to the linear Langmuirian blocking function utilized in previous dynamic deposition models for porous media. A comparison of theoretical model predictions based on RSA and Langmuirian blocking with experimental particle breakthrough curves demonstrates the superiority of RSA mechanics as a means of describing the transient nature of colloid deposition in granular porous media.

  7. A MEMS lamination technology based on sequential multilayer electrodeposition

    SciTech Connect

    Kim, M; Kim, J; Herrault, F; Schafer, R; Allen, MG

    2013-08-06

    A MEMS lamination technology based on sequential multilayer electrodeposition is presented. The process comprises three main steps: (1) automated sequential electrodeposition of permalloy (Ni80Fe20) structural and copper sacrificial layers to form multilayer structures of significant total thickness; (2) fabrication of polymeric anchor structures through the thickness of the multilayer structures and (3) selective removal of copper. The resulting structure is a set of air-insulated permalloy laminations, the separation of which is sustained by insulating polymeric anchor structures. Individual laminations have precisely controllable thicknesses ranging from 500 nm to 5 mu m, and each lamination layer is electrically isolated from adjacent layers by narrow air gaps of similar scale. In addition to air, interlamination insulators based on polymers are investigated. Interlamination air gaps with very high aspect ratio (>1:100) can be filled with polyvinylalcohol and polydimethylsiloxane. The laminated structures are characterized using scanning electron microscopy and atomic force microscopy to directly examine properties such as the roughness and the thickness uniformity of the layers. In addition, the quality of the electrical insulation between the laminations is evaluated by quantifying the eddy current within the sample as a function of frequency. Fabricated laminations are comprised of uniform, smooth (surface roughness < 100 nm) layers with effective electrical insulation for all layer thicknesses and insulator approaches studied. Such highly laminated structures have potential uses ranging from energy conversion to applications where composite materials with highly anisotropic mechanical or thermal properties are required.

  8. Asymmetric sequential Landau-Zener dynamics of Bose-condensed atoms in a cavity

    NASA Astrophysics Data System (ADS)

    Huang, Jiahao; Gong, Pu; Qin, Xizhou; Zhong, Honghua; Lee, Chaohong

    2016-08-01

    We explore the asymmetric sequential Landau-Zener (LZ) dynamics in an ensemble of interacting Bose-condensed two-level atoms coupled with a cavity field. Assuming the couplings between all atoms and the cavity field are identical, the interplay between atom-atom interaction and detuning may lead to a series of LZ transitions. Unlike the conventional sequential LZ transitions, which are symmetric to the zero detuning, the LZ transitions of Bose-condensed atoms in a cavity field are asymmetric and sensitively depend on the photon number distribution of the cavity. In LZ processes involving single excitation numbers, both the variance of the relative atom number and the step slope of the sequential population ladder are asymmetric, and the asymmetry becomes more significant for smaller excitation numbers. Furthermore, in LZ processes involving multiple excitation numbers, there may appear asymmetric population ladders with decreasing step heights. During a dynamical LZ process, due to the atom-cavity coupling, the cavity field shows dynamical collapses and revivals. In comparison with the symmetric LZ transitions in a classical field, the asymmetric LZ transitions in a cavity field originate from the photon-number-dependent Rabi frequency. The asymmetric sequential LZ dynamics of Bose-condensed atoms in a cavity field may open up a way to explore the fundamental many-body physics in coupled atom-photon systems.

  9. Sequential damage detection based on the continuous wavelet transform

    NASA Astrophysics Data System (ADS)

    Liao, Yizheng; Balafas, Konstantinos; Rajagopal, Ram; Kiremidjian, Anne S.

    2015-03-01

    This paper presents a sequential structural damage detection algorithm that is based on a statistical model for the wavelet transform of the structural responses. The detector uses the coefficients of the wavelet model and does not require prior knowledge of the structural properties. Principal Component Analysis is applied to select and extract the most sensitive features from the wavelet coefficients as the damage sensitive features. The damage detection algorithm is validated using the simulation data collected from a four-story steel moment frame. Various features have been explored and the detection algorithm was able to identify damage. Additionally, we show that for a desired probability of false alarm, the proposed detector is asymptotically optimal on the expected delay.

  10. A Fast and Precise Indoor Localization Algorithm Based on an Online Sequential Extreme Learning Machine †

    PubMed Central

    Zou, Han; Lu, Xiaoxuan; Jiang, Hao; Xie, Lihua

    2015-01-01

    Nowadays, developing indoor positioning systems (IPSs) has become an attractive research topic due to the increasing demands on location-based service (LBS) in indoor environments. WiFi technology has been studied and explored to provide indoor positioning service for years in view of the wide deployment and availability of existing WiFi infrastructures in indoor environments. A large body of WiFi-based IPSs adopt fingerprinting approaches for localization. However, these IPSs suffer from two major problems: the intensive costs of manpower and time for offline site survey and the inflexibility to environmental dynamics. In this paper, we propose an indoor localization algorithm based on an online sequential extreme learning machine (OS-ELM) to address the above problems accordingly. The fast learning speed of OS-ELM can reduce the time and manpower costs for the offline site survey. Meanwhile, its online sequential learning ability enables the proposed localization algorithm to adapt in a timely manner to environmental dynamics. Experiments under specific environmental changes, such as variations of occupancy distribution and events of opening or closing of doors, are conducted to evaluate the performance of OS-ELM. The simulation and experimental results show that the proposed localization algorithm can provide higher localization accuracy than traditional approaches, due to its fast adaptation to various environmental dynamics. PMID:25599427

  11. A fast and precise indoor localization algorithm based on an online sequential extreme learning machine.

    PubMed

    Zou, Han; Lu, Xiaoxuan; Jiang, Hao; Xie, Lihua

    2015-01-01

    Nowadays, developing indoor positioning systems (IPSs) has become an attractive research topic due to the increasing demands on location-based service (LBS) in indoor environments. WiFi technology has been studied and explored to provide indoor positioning service for years in view of the wide deployment and availability of existing WiFi infrastructures in indoor environments. A large body of WiFi-based IPSs adopt fingerprinting approaches for localization. However, these IPSs suffer from two major problems: the intensive costs of manpower and time for offline site survey and the inflexibility to environmental dynamics. In this paper, we propose an indoor localization algorithm based on an online sequential extreme learning machine (OS-ELM) to address the above problems accordingly. The fast learning speed of OS-ELM can reduce the time and manpower costs for the offline site survey. Meanwhile, its online sequential learning ability enables the proposed localization algorithm to adapt in a timely manner to environmental dynamics. Experiments under specific environmental changes, such as variations of occupancy distribution and events of opening or closing of doors, are conducted to evaluate the performance of OS-ELM. The simulation and experimental results show that the proposed localization algorithm can provide higher localization accuracy than traditional approaches, due to its fast adaptation to various environmental dynamics. PMID:25599427

  12. Control of water distribution networks with dynamic DMA topology using strictly feasible sequential convex programming

    NASA Astrophysics Data System (ADS)

    Wright, Robert; Abraham, Edo; Parpas, Panos; Stoianov, Ivan

    2015-12-01

    The operation of water distribution networks (WDN) with a dynamic topology is a recently pioneered approach for the advanced management of District Metered Areas (DMAs) that integrates novel developments in hydraulic modeling, monitoring, optimization, and control. A common practice for leakage management is the sectorization of WDNs into small zones, called DMAs, by permanently closing isolation valves. This facilitates water companies to identify bursts and estimate leakage levels by measuring the inlet flow for each DMA. However, by permanently closing valves, a number of problems have been created including reduced resilience to failure and suboptimal pressure management. By introducing a dynamic topology to these zones, these disadvantages can be eliminated while still retaining the DMA structure for leakage monitoring. In this paper, a novel optimization method based on sequential convex programming (SCP) is outlined for the control of a dynamic topology with the objective of reducing average zone pressure (AZP). A key attribute for control optimization is reliable convergence. To achieve this, the SCP method we propose guarantees that each optimization step is strictly feasible, resulting in improved convergence properties. By using a null space algorithm for hydraulic analyses, the computations required are also significantly reduced. The optimized control is actuated on a real WDN operated with a dynamic topology. This unique experimental program incorporates a number of technologies set up with the objective of investigating pioneering developments in WDN management. Preliminary results indicate AZP reductions for a dynamic topology of up to 6.5% over optimally controlled fixed topology DMAs. This article was corrected on 12 JAN 2016. See the end of the full text for details.

  13. CFD simulation of hemodynamics in sequential and individual coronary bypass grafts based on multislice CT scan datasets.

    PubMed

    Hajati, Omid; Zarrabi, Khalil; Karimi, Reza; Hajati, Azadeh

    2012-01-01

    There is still controversy over the differences in the patency rates of the sequential and individual coronary artery bypass grafting (CABG) techniques. The purpose of this paper was to non-invasively evaluate hemodynamic parameters using complete 3D computational fluid dynamics (CFD) simulations of the sequential and the individual methods based on the patient-specific data extracted from computed tomography (CT) angiography. For CFD analysis, the geometric model of coronary arteries was reconstructed using an ECG-gated 64-detector row CT. Modeling the sequential and individual bypass grafting, this study simulates the flow from the aorta to the occluded posterior descending artery (PDA) and the posterior left ventricle (PLV) vessel with six coronary branches based on the physiologically measured inlet flow as the boundary condition. The maximum calculated wall shear stress (WSS) in the sequential and the individual models were estimated to be 35.1 N/m(2) and 36.5 N/m(2), respectively. Compared to the individual bypass method, the sequential graft has shown a higher velocity at the proximal segment and lower spatial wall shear stress gradient (SWSSG) due to the flow splitting caused by the side-to-side anastomosis. Simulated results combined with its surgical benefits including the requirement of shorter vein length and fewer anastomoses advocate the sequential method as a more favorable CABG method. PMID:23365974

  14. Sequential dynamics in the motif of excitatory coupled elements

    NASA Astrophysics Data System (ADS)

    Korotkov, Alexander G.; Kazakov, Alexey O.; Osipov, Grigory V.

    2015-11-01

    In this article a new model of motif (small ensemble) of neuron-like elements is proposed. It is built with the use of the generalized Lotka-Volterra model with excitatory couplings. The main motivation for this work comes from the problems of neuroscience where excitatory couplings are proved to be the predominant type of interaction between neurons of the brain. In this paper it is shown that there are two modes depending on the type of coupling between the elements: the mode with a stable heteroclinic cycle and the mode with a stable limit cycle. Our second goal is to examine the chaotic dynamics of the generalized three-dimensional Lotka-Volterra model.

  15. Laser-subcycle control of sequential double-ionization dynamics of helium

    NASA Astrophysics Data System (ADS)

    Schöffler, Markus S.; Xie, Xinhua; Wustelt, Philipp; Möller, Max; Roither, Stefan; Kartashov, Daniil; Sayler, A. Max; Baltuska, Andrius; Paulus, Gerhard G.; Kitzler, Markus

    2016-06-01

    We present measured momentum distributions on the double ionization of helium with intense, near-circularly-polarized few-cycle laser pulses with a known carrier-envelope offset phase (CEP). The capability of obtaining CEP-resolved momentum distributions enables us to observe signatures of the various combinations of laser-half-cycle two-electron emissions. By comparison to semiclassical trajectory simulations, we succeed in assigning the corresponding structures in the measured distributions to certain two-electron emission dynamics. Based on this possibility, we demonstrate that the sequential double-ionization dynamics can be sensitively controlled with the pulse duration and the laser peak intensity. For the shortest pulse durations and not too high intensities we find that the two electrons are dominantly emitted with a delay of roughly a laser half cycle. For a just slightly increased intensity we find evidence that at least one of the two electrons is surprisingly likely emitted in between the peaks of the laser field oscillations rather than at the field maxima. The simulations reproduce the signatures of these kinds of two-electron emissions overall relatively well.

  16. On theoretical issues of computer simulations sequential dynamical systems

    SciTech Connect

    Barrett, C.L.; Mortveit, H.S.; Reidys, C.M.

    1998-12-01

    The authors study a class of discrete dynamical systems that is motivated by the generic structure of simulations. The systems consist of the following data: (a) a finite graph Y with vertex set {l_brace}1,...,n{r_brace} where each vertex has a binary state, (b) functions F{sub i}:F{sub 2}{sup n} {r_arrow} F{sub 2}{sup n} and (c) an update ordering {pi}. The functions F{sub i} update the binary state of vertex i as a function of the state of vertex i and its Y-neighbors and leave the states of all other vertices fixed. The update ordering is a permutation of the Y-vertices. They derive a decomposition result, characterize invertible SDS and study fixed points. In particular they analyze how many different SDS that can be obtained by reordering a given multiset of update functions and give a criterion for when one can derive concentration results on this number. Finally, some specific SDS are investigated.

  17. Spatiotemporal Mining of Time-Series Remote Sensing Images Based on Sequential Pattern Mining

    NASA Astrophysics Data System (ADS)

    Liu, H. C.; He, G. J.; Zhang, X. M.; Jiang, W.; Ling, S. G.

    2015-07-01

    With the continuous development of satellite techniques, it is now possible to acquire a regular series of images concerning a given geographical zone with both high accuracy and low cost. Research on how best to effectively process huge volumes of observational data obtained on different dates for a specific geographical zone, and to exploit the valuable information regarding land cover contained in these images has received increasing interest from the remote sensing community. In contrast to traditional land cover change measures using pair-wise comparisons that emphasize the compositional or configurational changes between dates, this research focuses on the analysis of the temporal sequence of land cover dynamics, which refers to the succession of land cover types for a given area over more than two observational periods. Using a time series of classified Landsat images, ranging from 2006 to 2011, a sequential pattern mining method was extended to this spatiotemporal context to extract sets of connected pixels sharing similar temporal evolutions. The resultant sequential patterns could be selected (or not) based on the range of support values. These selected patterns were used to explore the spatial compositions and temporal evolutions of land cover change within the study region. Experimental results showed that continuous patterns that represent consistent land cover over time appeared as quite homogeneous zones, which agreed with our domain knowledge. Discontinuous patterns that represent land cover change trajectories were dominated by the transition from vegetation to bare land, especially during 2009-2010. This approach quantified land cover changes in terms of the percentage area affected and mapped the spatial distribution of these changes. Sequential pattern mining has been used for string mining or itemset mining in transactions analysis. The expected novel significance of this study is the generalization of the application of the sequential pattern

  18. Sequential Model-Based Detection in a Shallow Ocean Acoustic Environment

    SciTech Connect

    Candy, J V

    2002-03-26

    A model-based detection scheme is developed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an embedded model-based processor and a reference model in a sequential likelihood detection scheme. The monitor is therefore called a sequential reference detector. The underlying theory for the design is developed and discussed in detail.

  19. DYNAMIC ANALYSIS OF THE BULK TRITIUM SHIPPING PACKAGE SUBJECTED TO CLOSURE TORQUES AND SEQUENTIAL IMPACTS

    SciTech Connect

    Wu, T; Paul Blanton, P; Kurt Eberl, K

    2007-07-09

    This paper presents a finite-element technique to simulate the structural responses and to evaluate the cumulative damage of a radioactive material packaging requiring bolt closure-tightening torque and subjected to the scenarios of the Hypothetical Accident Conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR71). Existing finite-element methods for modeling closure stresses from bolt pre-load are not readily adaptable to dynamic analyses. The HAC events are required to occur sequentially per 10CFR71 and thus the evaluation of the cumulative damage is desirable. Generally, each HAC event is analyzed separately and the cumulative damage is partially addressed by superposition. This results in relying on additional physical testing to comply with 10CFR71 requirements for assessment of cumulative damage. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage. This methodology provides improved numerical solutions in compliance with the 10CFR71 requirements for sequential HAC tests. Analyses were performed for the Bulk Tritium Shipping Package (BTSP) designed by Savannah River National Laboratory to demonstrate the applications of the technique. The methodology proposed simulates the closure bolt torque preload followed by the sequential HAC events, the 30-foot drop and the 30-foot dynamic crush. The analytical results will be compared to the package test data.

  20. Dynamic Modelling of Aquifer Level Using Space-Time Kriging and Sequential Gaussian Simulation

    NASA Astrophysics Data System (ADS)

    Varouchakis, Emmanouil A.; Hristopulos, Dionisis T.

    2016-04-01

    Geostatistical models are widely used in water resources management projects to represent and predict the spatial variability of aquifer levels. In addition, they can be applied as surrogate to numerical hydrological models if the hydrogeological data needed to calibrate the latter are not available. For space-time data, spatiotemporal geostatistical approaches can model the aquifer level variability by incorporating complex space-time correlations. A major advantage of such models is that they can improve the reliability of predictions compared to purely spatial or temporal models in areas with limited spatial and temporal data availability. The identification and incorporation of a spatiotemporal trend model can further increase the accuracy of groundwater level predictions. Our goal is to derive a geostatistical model of dynamic aquifer level changes in a sparsely gauged basin on the island of Crete (Greece). The available data consist of bi-annual (dry and wet hydrological period) groundwater level measurements at 11 monitoring locations for the time period 1981 to 2010. We identify a spatiotemporal trend function that follows the overall drop of the aquifer level over the study period. The correlation of the residuals is modeled using a non-separable space-time variogram function based on the Spartan covariance family. The space-time Residual Kriging (STRK) method is then applied to combine the estimated trend and the residuals into dynamic predictions of groundwater level. Sequential Gaussian Simulation is also employed to determine the uncertainty of the spatiotemporal model (trend and covariance) parameters. This stochastic modelling approach produces multiple realizations, ranks the prediction results on the basis of specified criteria, and captures the range of the uncertainty. The model projections recommend that in 2032 a part of the basin will be under serious threat as the aquifer level will approximate the sea level boundary.

  1. Use of solid phase extraction for the sequential injection determination of alkaline phosphatase activity in dynamic water systems.

    PubMed

    Santos, Inês C; Mesquita, Raquel B R; Bordalo, Adriano A; Rangel, António O S S

    2012-08-30

    In this work, a solid phase extraction sequential injection methodology for the determination of alkaline phosphatase activity in dynamic water systems was developed. The determination of the enzymatic activity was based on the spectrophotometric detection of a coloured product, p-nitrophenol, at 405 nm. The p-nitrophenol is the product of the catalytic decomposition of p-nitrophenyl phosphate, a non-coloured substrate. Considering the low levels expected in natural waters and exploiting the fact of alkaline phosphatase being a metalloprotein, the enzyme was pre-concentrated in-line using a NTA Superflow resin charged with Zn(2+) ions. The developed sequential injection method enabled a quantification range of 0.044-0.441 unit mL(-1) of enzyme activity with a detection limit of 0.0082 unit mL(-1) enzyme activity (1.9 μmol L(-1) of pNP) and a determination rate of 17 h(-1). Recovery tests confirmed the accuracy of the developed sequential injection method and it was effectively applied to different natural waters and to plant root extracts. PMID:22939148

  2. Non-sequential Recursive Pair Substitutions and Numerical Entropy Estimates in Symbolic Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Calcagnile, Lucio M.; Galatolo, Stefano; Menconi, Giulia

    2010-12-01

    We numerically test the method of non-sequential recursive pair substitutions to estimate the entropy of an ergodic source. We compare its performance with other classical methods to estimate the entropy (empirical frequencies, return times, and Lyapunov exponent). We have considered as a benchmark for the methods several systems with different statistical properties: renewal processes, dynamical systems provided and not provided with a Markov partition, and slow or fast decay of correlations. Most experiments are supported by rigorous mathematical results, which are explained in the paper.

  3. Developing a Self-Report-Based Sequential Analysis Method for Educational Technology Systems: A Process-Based Usability Evaluation

    ERIC Educational Resources Information Center

    Lin, Yi-Chun; Hsieh, Ya-Hui; Hou, Huei-Tse

    2015-01-01

    The development of a usability evaluation method for educational systems or applications, called the self-report-based sequential analysis, is described herein. The method aims to extend the current practice by proposing self-report-based sequential analysis as a new usability method, which integrates the advantages of self-report in survey…

  4. A Sequential Dynamic Bayesian Network for Pore Pressure Prediction and Quantification of Uncertainty.

    NASA Astrophysics Data System (ADS)

    Oughton, R. H.; Wooff, D. A.; Hobbs, R. W.; Swarbrick, R. E.

    2014-12-01

    Pore pressure prediction is vital when drilling a well, as unexpected overpressure can cause drilling challenges and uncontrolled hydrocarbon leakage. One cause of overpressure is when pore fluid is trapped during burial and takes on part of the lithostatic load. Predictions often use porosity-based techniques, such as the Eaton Ratio method and equivalent depth method. These rely on an idealised compaction trend and use a single wireline log as a proxy for porosity. Such methods do not account for the many sources of uncertainty, or for the multivariate nature of the system. We propose a sequential dynamic Bayesian network (SDBN) as a solution to these issues. The SDBN models the quantities in the system (such as pressures, porosity, lithology, wireline logs, fluid properties and so on) using conditional probability distributions to capture their joint behaviour. A compaction model is central to the SDBN, relating porosity to vertical effective stress, with uncertainty in the relationship, so that the logic is similar to that of the equivalent depth method. The probability distribution for porosity depends on VES and lithology, with much more uncertainty in sandstone-like rocks than in shales to reflect a general lack of understanding of sandstone compaction. The distributions of the wireline logs depend on porosity and lithology, along with other quantities, and so when they are observed the SDBN learns about porosity and lithology and in turn VES and pore pressure, using Bayes theorem. The probability distribution for each quantity in the SDBN is updated in light of any data, so that rather than giving a single-valued prediction for pore pressure, the SDBN gives a prediction with uncertainty that takes into account the whole system, knowledge and data. The dynamic nature of the SDBN enables it to use the bulk density to calculate total vertical stress, and to account for the dissipation of pore pressure. The vertical correlation in the SDBN means it is suited to

  5. Coordinated Action of Fast and Slow Reserves for Optimal Sequential and Dynamic Emergency Reserve Activation

    NASA Astrophysics Data System (ADS)

    Salkuti, Surender Reddy; Bijwe, P. R.; Abhyankar, A. R.

    2016-04-01

    This paper proposes an optimal dynamic reserve activation plan after the occurrence of an emergency situation (generator/transmission line outage, load increase or both). An optimal plan is developed to handle the emergency situation, using coordinated action of fast and slow reserves, for secure operation with minimum overall cost. This paper considers the reserves supplied by generators (spinning reserves) and loads (demand-side reserves). The optimal backing down of costly/fast reserves and bringing up of slow reserves in each sub-interval in an integrated manner is proposed. The simulation studies are performed on IEEE 30, 57 and 300 bus test systems to demonstrate the advantage of proposed integrated/dynamic reserve activation plan over the conventional/sequential approach.

  6. SPMBR: a scalable algorithm for mining sequential patterns based on bitmaps

    NASA Astrophysics Data System (ADS)

    Xu, Xiwei; Zhang, Changhai

    2013-12-01

    Now some sequential patterns mining algorithms generate too many candidate sequences, and increase the processing cost of support counting. Therefore, we present an effective and scalable algorithm called SPMBR (Sequential Patterns Mining based on Bitmap Representation) to solve the problem of mining the sequential patterns for large databases. Our method differs from previous related works of mining sequential patterns. The main difference is that the database of sequential patterns is represented by bitmaps, and a simplified bitmap structure is presented firstly. In this paper, First the algorithm generate candidate sequences by SE(Sequence Extension) and IE(Item Extension), and then obtain all frequent sequences by comparing the original bitmap and the extended item bitmap .This method could simplify the problem of mining the sequential patterns and avoid the high processing cost of support counting. Both theories and experiments indicate that the performance of SPMBR is predominant for large transaction databases, the required memory size for storing temporal data is much less during mining process, and all sequential patterns can be mined with feasibility.

  7. Sequential interpenetrating polymer networks produced from vegetable oil based polyurethane and poly(methyl methacrylate).

    PubMed

    Kong, Xiaohua; Narine, Suresh S

    2008-08-01

    Sequential interpenetrating polymer networks (IPNs) were prepared using polyurethane produced from a canola oil based polyol with primary terminal functional groups and poly(methyl methacrylate) (PMMA). The properties of the material were studied and compared to the IPNs made from commercial castor oil using dynamic mechanical analysis, differential scanning calorimetry, as well as tensile measurements. The morphology of the IPNs was investigated using scanning electron microscopy and transmission electron microscopy. The chemical diversity of the starting materials allowed the evaluation of the effects of dangling chains and graftings on the properties of the IPNs. The polymerization process of canola oil based IPNs was accelerated because of the utilization of polyol with primary functional groups, which efficiently lessened the effect of dangling chains and yielded a higher degree of phase mixing. The mechanical properties of canola oil based IPNs containing more than 75 wt % PMMA were comparable to the corresponding castor oil based IPNs; both were superior to those of the constituent polymers due to the finely divided rubber and plastic combination structures in these IPNs. However, when PMMA content was less than 65 wt %, canola oil based IPNs exhibited a typical mechanical behavior of rigid plastics, whereas castor oil based IPNs showed a typical mechanical behavior of soft rubber. It is proposed that these new IPN materials with high performance prepared from alternative renewable resources can prove to be valuable substitutes for existing materials in various applications. PMID:18624453

  8. Physics-based, Bayesian sequential detection method and system for radioactive contraband

    DOEpatents

    Candy, James V; Axelrod, Michael C; Breitfeller, Eric F; Chambers, David H; Guidry, Brian L; Manatt, Douglas R; Meyer, Alan W; Sale, Kenneth E

    2014-03-18

    A distributed sequential method and system for detecting and identifying radioactive contraband from highly uncertain (noisy) low-count, radionuclide measurements, i.e. an event mode sequence (EMS), using a statistical approach based on Bayesian inference and physics-model-based signal processing based on the representation of a radionuclide as a monoenergetic decomposition of monoenergetic sources. For a given photon event of the EMS, the appropriate monoenergy processing channel is determined using a confidence interval condition-based discriminator for the energy amplitude and interarrival time and parameter estimates are used to update a measured probability density function estimate for a target radionuclide. A sequential likelihood ratio test is then used to determine one of two threshold conditions signifying that the EMS is either identified as the target radionuclide or not, and if not, then repeating the process for the next sequential photon event of the EMS until one of the two threshold conditions is satisfied.

  9. Tuning the Brake While Raising the Stake: Network Dynamics during Sequential Decision-Making

    PubMed Central

    Meder, David; Haagensen, Brian Numelin; Hulme, Oliver; Morville, Tobias; Gelskov, Sofie; Herz, Damian Marc; Diomsina, Beata; Christensen, Mark Schram; Madsen, Kristoffer Hougaard

    2016-01-01

    When gathering valued goods, risk and reward are often coupled and escalate over time, for instance, during foraging, trading, or gambling. This escalating frame requires agents to continuously balance expectations of reward against those of risk. To address how the human brain dynamically computes these tradeoffs, we performed whole-brain fMRI while healthy young individuals engaged in a sequential gambling task. Participants were repeatedly confronted with the option to continue with throwing a die to accumulate monetary reward under escalating risk, or the alternative option to stop to bank the current balance. Within each gambling round, the accumulation of gains gradually increased reaction times for “continue” choices, indicating growing uncertainty in the decision to continue. Neural activity evoked by “continue” choices was associated with growing activity and connectivity of a cortico-subcortical “braking” network that positively scaled with the accumulated gains, including pre-supplementary motor area (pre-SMA), inferior frontal gyrus, caudate, and subthalamic nucleus (STN). The influence of the STN on continue-evoked activity in the pre-SMA was predicted by interindividual differences in risk-aversion attitudes expressed during the gambling task. Furthermore, activity in dorsal anterior cingulate cortex (ACC) reflected individual choice tendencies by showing increased activation when subjects made nondefault “continue” choices despite an increasing tendency to stop, but ACC activity did not change in proportion with subjective choice uncertainty. Together, the results implicate a key role of dorsal ACC, pre-SMA, inferior frontal gyrus, and STN in computing the trade-off between escalating reward and risk in sequential decision-making. SIGNIFICANCE STATEMENT Using a paradigm where subjects experienced increasing potential rewards coupled with increasing risk, this study addressed two unresolved questions in the field of decision

  10. A stacked sequential learning method for investigator name recognition from web-based medical articles

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoli; Zou, Jie; Le, Daniel X.; Thoma, George

    2010-01-01

    "Investigator Names" is a newly required field in MEDLINE citations. It consists of personal names listed as members of corporate organizations in an article. Extracting investigator names automatically is necessary because of the increasing volume of articles reporting collaborative biomedical research in which a large number of investigators participate. In this paper, we present an SVM-based stacked sequential learning method in a novel application - recognizing named entities such as the first and last names of investigators from online medical journal articles. Stacked sequential learning is a meta-learning algorithm which can boost any base learner. It exploits contextual information by adding the predicted labels of the surrounding tokens as features. We apply this method to tag words in text paragraphs containing investigator names, and demonstrate that stacked sequential learning improves the performance of a nonsequential base learner such as an SVM classifier.

  11. Sequential or superexchange mechanism in bridged electron transfer distinguished by dynamics at a bridging molecule.

    PubMed

    Saito, Keisuke; Kikuchi, Tomoaki; Mukai, Koichiro; Sumi, Hitoshi

    2009-07-14

    Two kinds of mechanisms are well known for electron transfer (ET) in the system DMA where a donor D and an acceptor A are fixed in a close distance by a bridging molecule M. When the free energy DeltaG(m) of the intermediate state |m of DM(-)A is much higher than the thermal energy k(B)T above the initial state of D(-)MA, the ET occurs unistep from D to A by the superexchange (SX) mechanism, passing |m as a quantum-mechanical virtual state. However, when DeltaG(m) becomes not much higher than k(B)T, the ordinary sequential (OS) ET may manifest itself, where the second ET from |m to the final state of DMA(-) takes place after thermalization of phonons in |m. Recently, much interest has been aroused in how the SX mechanism switches to the OS one as DeltaG(m) is lowered. This subject has often been described conventionally by summation of the rate constant for the SX mechanism and that for the OS one. However, such convention cannot be justified, since these mechanisms are realized in mutually opposite limits concerned with dynamics in mediation of ET by a bridging molecule, hence they cannot both be realized simultaneously in a single system. An observation of such a bridged ET by Paulson, Miller, Gan and Closs (J. Am. Chem. Soc. 2005, 127, 4860) provides a good example of this feature. Describing their observation in a unified framework for the ET, it is shown that the switch occurs at DeltaG(m) congruent with-0.5 eV, which is much lower than 0.3 eV reported by them, where the hot-sequential ET reveals itself, taking place during thermalization of phonons in |m. PMID:19551196

  12. Dynamic Simulation of Shipping Package Subjected to Torque Load and Sequential Impacts

    SciTech Connect

    Wu, T

    2006-04-17

    A numerical technique has been developed to simulate the structural responses of radioactive material packaging components requiring closure-tightening torque to the scenarios of the hypothetical accident conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR 71). A rigorous solution to this type of problem poses a considerable mathematical challenge. Conventional methods for evaluating the residue stresses due to the torque load are either inaccurate or not applicable to dynamic analyses. In addition, the HAC events occur sequentially and the cumulative damage to the package needs to be evaluated. Commonly, individual HAC events are analyzed separately and the cumulative damage is not addressed. As a result, strict compliance of the package with the requirements specified in 10CFR 71 is usually demonstrated by physical testing. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage in numerical solutions. The analyses demonstrating use of this technique were performed to determine the cumulative damage of torque preload, a 30-foot drop, a 30-foot dynamic crush and a 40-inch free fall onto a mild steel pipe.

  13. Multi-volatile method for aroma analysis using sequential dynamic headspace sampling with an application to brewed coffee.

    PubMed

    Ochiai, Nobuo; Tsunokawa, Jun; Sasamoto, Kikuo; Hoffmann, Andreas

    2014-12-01

    A novel multi-volatile method (MVM) using sequential dynamic headspace (DHS) sampling for analysis of aroma compounds in aqueous sample was developed. The MVM consists of three different DHS method parameters sets including choice of the replaceable adsorbent trap. The first DHS sampling at 25 °C using a carbon-based adsorbent trap targets very volatile solutes with high vapor pressure (>20 kPa). The second DHS sampling at 25 °C using the same type of carbon-based adsorbent trap targets volatile solutes with moderate vapor pressure (1-20 kPa). The third DHS sampling using a Tenax TA trap at 80 °C targets solutes with low vapor pressure (<1 kPa) and/or hydrophilic characteristics. After the 3 sequential DHS samplings using the same HS vial, the three traps are sequentially desorbed with thermal desorption in reverse order of the DHS sampling and the desorbed compounds are trapped and concentrated in a programmed temperature vaporizing (PTV) inlet and subsequently analyzed in a single GC-MS run. Recoveries of the 21 test aroma compounds for each DHS sampling and the combined MVM procedure were evaluated as a function of vapor pressure in the range of 0.000088-120 kPa. The MVM provided very good recoveries in the range of 91-111%. The method showed good linearity (r2>0.9910) and high sensitivity (limit of detection: 1.0-7.5 ng mL(-1)) even with MS scan mode. The feasibility and benefit of the method was demonstrated with analysis of a wide variety of aroma compounds in brewed coffee. Ten potent aroma compounds from top-note to base-note (acetaldehyde, 2,3-butanedione, 4-ethyl guaiacol, furaneol, guaiacol, 3-methyl butanal, 2,3-pentanedione, 2,3,5-trimethyl pyrazine, vanillin, and 4-vinyl guaiacol) could be identified together with an additional 72 aroma compounds. Thirty compounds including 9 potent aroma compounds were quantified in the range of 74-4300 ng mL(-1) (RSD<10%, n=5). PMID:25456588

  14. A novel anticancer theranostic pro-prodrug based on hypoxia and photo sequential control.

    PubMed

    Feng, Weipei; Gao, Chunyue; Liu, Wei; Ren, Huihui; Wang, Chao; Ge, Kun; Li, Shenghui; Zhou, Guoqiang; Li, Hongyan; Wang, Shuxiang; Jia, Guang; Li, Zhenhua; Zhang, Jinchao

    2016-08-01

    A novel anticancer pro-prodrug (GMC-CAE-NO2) with diagnosis and therapy functions based on hypoxia and photo sequential control was designed. It provides a platform for constructing theranostic pro-prodrugs to release active drugs controlled by hypoxic status and UV illumination. PMID:27379361

  15. Sequential Processes in Palladium-Catalyzed Silicon-Based Cross-Coupling

    PubMed Central

    Denmark, Scott E.; Liu, Jack H.-C.

    2012-01-01

    Although developed somewhat later, silicon-based cross-coupling has become a viable alternative to the more conventional Suzuki-Miyaura, Stille-Kosugi-Migita, and Negishi cross-coupling reactions because of its broad substrate scope, high stability of silicon-containing reagents, and low toxicity of waste streams. An empowering and yet underappreciated feature unique to silicon-based cross-coupling is the wide range of sequential processes available. In these processes, simple precursors are first converted to complex silicon-containing cross-coupling substrates, and the subsequent silicon-based cross-coupling reaction affords an even more highly functionalized product in a stereoselective fashion. In so doing, structurally simple and inexpensive starting materials are quickly transformed into value-added and densely substituted products. Therefore, sequential processes are often useful in constructing the carbon backbones of natural products. In this review, studies of sequential processes involving silicon-based cross-coupling are discussed. Additionally, the total syntheses that utilize these sequential processes are also presented. PMID:23293392

  16. Multidimensional treatment of stochastic solvent dynamics in photoinduced proton-coupled electron transfer processes: sequential, concerted, and complex branching mechanisms.

    PubMed

    Soudackov, Alexander V; Hazra, Anirban; Hammes-Schiffer, Sharon

    2011-10-14

    A theoretical approach for the multidimensional treatment of photoinduced proton-coupled electron transfer (PCET) processes in solution is presented. This methodology is based on the multistate continuum theory with an arbitrary number of diabatic electronic states representing the relevant charge distributions in a general PCET system. The active electrons and transferring proton(s) are treated quantum mechanically, and the electron-proton vibronic free energy surfaces are represented as functions of multiple scalar solvent coordinates corresponding to the single electron and proton transfer reactions involved in the PCET process. A dynamical formulation of the dielectric continuum theory is used to derive a set of coupled generalized Langevin equations of motion describing the time evolution of these collective solvent coordinates. The parameters in the Langevin equations depend on the solvent properties, such as the dielectric constants, relaxation time, and molecular moment of inertia, as well as the solute properties. The dynamics of selected intramolecular nuclear coordinates, such as the proton donor-acceptor distance or a torsional angle within the PCET complex, may also be included in this formulation. A surface hopping method in conjunction with the Langevin equations of motion is used to simulate the nonadiabatic dynamics on the multidimensional electron-proton vibronic free energy surfaces following photoexcitation. This theoretical treatment enables the description of both sequential and concerted mechanisms, as well as more complex processes involving a combination of these mechanisms. The application of this methodology to a series of model systems corresponding to collinear and orthogonal PCET illustrates fundamental aspects of these different mechanisms and elucidates the significance of proton vibrational relaxation and nonequilibrium solvent dynamics. PMID:22010706

  17. On-line dynamic fractionation and automatic determination of inorganic phosphorus in environmental solid substrates exploiting sequential injection microcolumn extraction and flow injection analysis.

    PubMed

    Buanuam, Janya; Miró, Manuel; Hansen, Elo Harald; Shiowatana, Juwadee

    2006-06-16

    Sequential injection microcolumn extraction (SI-MCE) based on the implementation of a soil-containing microcartridge as external reactor in a sequential injection network is, for the first time, proposed for dynamic fractionation of macronutrients in environmental solids, as exemplified by the partitioning of inorganic phosphorus in agricultural soils. The on-line fractionation method capitalises on the accurate metering and sequential exposure of the various extractants to the solid sample by application of programmable flow as precisely coordinated by a syringe pump. Three different soil phase associations for phosphorus, that is, exchangeable, Al- and Fe-bound, and Ca-bound fractions, were elucidated by accommodation in the flow manifold of the three steps of the Hieltjes-Lijklema (HL) scheme involving the use of 1.0M NH4Cl, 0.1M NaOH and 0.5M HCl, respectively, as sequential leaching reagents. The precise timing and versatility of SI for tailoring various operational extraction modes were utilized for investigating the extractability and the extent of phosphorus re-distribution for variable partitioning times. Automatic spectrophotometric determination of soluble reactive phosphorus in soil extracts was performed by a flow injection (FI) analyser based on the Molybdenum Blue (MB) chemistry. The 3sigma detection limit was 0.02 mg P L(-1) while the linear dynamic range extended up to 20 mg P L(-1) regardless of the extracting media. Despite the variable chemical composition of the HL extracts, a single FI set-up was assembled with no need for either manifold re-configuration or modification of chemical composition of reagents. The mobilization of trace elements, such as Cd, often present in grazed pastures as a result of the application of phosphate fertilizers, was also explored in the HL fractions by electrothermal atomic absorption spectrometry. PMID:17723403

  18. Organizational Readiness for Stage-Based Dynamics of Innovation Implementation

    ERIC Educational Resources Information Center

    Simpson, D. Dwayne

    2009-01-01

    Implementing innovations in social and health-related service programs is a dynamic stage-based process. This article discusses training, adoption, implementation, and practice as sequential elements of a conceptual framework for effective preparation and implementation of evidence-based innovations. However, systems need to be prepared for change…

  19. A deterministic sequential maximin Latin hypercube design method using successive local enumeration for metamodel-based optimization

    NASA Astrophysics Data System (ADS)

    Long, Teng; Wu, Di; Chen, Xin; Guo, Xiaosong; Liu, Li

    2016-06-01

    Space-filling and projective properties of design of computer experiments methods are desired features for metamodelling. To enable the production of high-quality sequential samples, this article presents a novel deterministic sequential maximin Latin hypercube design (LHD) method using successive local enumeration, notated as sequential-successive local enumeration (S-SLE). First, a mesh-mapping algorithm is proposed to map the positions of existing points into the new hyper-chessboard to ensure the projective property. According to the maximin distance criterion, new sequential samples are generated through successive local enumeration iterations to improve the space-filling uniformity. Through a number of comparative studies, several appealing merits of S-SLE are demonstrated: (1) S-SLE outperforms several existing LHD methods in terms of sequential sampling quality; (2) it is flexible and robust enough to produce high-quality multiple-stage sequential samples; and (3) the proposed method can improve the overall performance of sequential metamodel-based optimization algorithms. Thus, S-SLE is a promising sequential LHD method for metamodel-based optimization.

  20. An anomaly detection and isolation scheme with instance-based learning and sequential analysis

    SciTech Connect

    Yoo, T. S.; Garcia, H. E.

    2006-07-01

    This paper presents an online anomaly detection and isolation (FDI) technique using an instance-based learning method combined with a sequential change detection and isolation algorithm. The proposed method uses kernel density estimation techniques to build statistical models of the given empirical data (null hypothesis). The null hypothesis is associated with the set of alternative hypotheses modeling the abnormalities of the systems. A decision procedure involves a sequential change detection and isolation algorithm. Notably, the proposed method enjoys asymptotic optimality as the applied change detection and isolation algorithm is optimal in minimizing the worst mean detection/isolation delay for a given mean time before a false alarm or a false isolation. Applicability of this methodology is illustrated with redundant sensor data set and its performance. (authors)

  1. Development of New Lipid-Based Paclitaxel Nanoparticles Using Sequential Simplex Optimization

    PubMed Central

    Dong, Xiaowei; Mattingly, Cynthia A.; Tseng, Michael; Cho, Moo; Adams, Val R.; Mumper, Russell J.

    2008-01-01

    The objective of these studies was to develop Cremophor-free lipid-based paclitaxel (PX) nanoparticle formulations prepared from warm microemulsion precursors. To identify and optimize new nanoparticles, experimental design was performed combining Taguchi array and sequential simplex optimization. The combination of Taguchi array and sequential simplex optimization efficiently directed the design of paclitaxel nanoparticles. Two optimized paclitaxel nanoparticles (NPs) were obtained: G78 NPs composed of glyceryl tridodecanoate (GT) and polyoxyethylene 20-stearyl ether (Brij 78), and BTM NPs composed of Miglyol 812, Brij 78 and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS). Both nanoparticles successfully entrapped paclitaxel at a final concentration of 150 μg/ml (over 6% drug loading) with particle sizes less than 200 nm and over 85% of entrapment efficiency. These novel paclitaxel nanoparticles were stable at 4°C over three months and in PBS at 37°C over 102 hours as measured by physical stability. Release of paclitaxel was slow and sustained without initial burst release. Cytotoxicity studies in MDA-MB-231 cancer cells showed that both nanoparticles have similar anticancer activities compared to Taxol®. Interestingly, PX BTM nanocapsules could be lyophilized without cryoprotectants. The lyophilized powder comprised only of PX BTM NPs in water could be rapidly rehydrated with complete retention of original physicochemical properties, in-vitro release properties, and cytotoxicity profile. Sequential Simplex Optimization has been utilized to identify promising new lipid-based paclitaxel nanoparticles having useful attributes. PMID:19111929

  2. Aliphatic and aromatic plant biopolymer dynamics in soil particles isolated from sequential density fractionation

    NASA Astrophysics Data System (ADS)

    Caldwell, B.; Filley, T.; Sollins, P.; Lajtha, K.; Swanston, C.; Kleber, M.; Kramer, M.

    2007-12-01

    A recent multi-layer-based soil organic matter-mineral interaction mechanistic model to describe the nature of soil organic matter-mineral surface mechanism for soil organic matter stabilization predicts that proteinaceous and aliphatic materials establish the core of strong binding-interactions upon which other organic matter is layered. A key methodology providing data underpinning this hypothesis is sequential density fractionation where soil is partitioned into particles of increasing density with the assumption that a partial control on organic matter distribution through density series is the thickness of its layering. Four soils of varying mineralogy and texture were investigated for their biopolymer, isotopic, and mineralogical properties. Light fractions (<1.8 g/cm3), although dominanted by organic detritus, did not always contain the highest concentration of lignin and substituted fatty acids from cutin and suberin while heavier fractions, 1.8-2.6 g/cm3, exhibited a progressive decrease in concentration in plant derived biopolymers with density. Extractable lignin phenols exhibited a progressive oxidation state with density. The concentration of biopolymers roughly mirrored the C:N ratio of soil particles which dropped consistently with increasing particle density. Although, in all soils, both lignin phenols and SFA concentration generally decreased with increasing density the ratio SFA/lignin varied with density and depending upon the soil. All soils, except the oxisol, exhibited an increase in SFA with respect to lignin suggesting a selective stabilization of those material with respect to lignin. In the oxisol, which showed little variation in its hematite dominated mineralogy across density, SFA/lignin remained constant, potentially indicating a greater capacity to stabilize lignin in that system. Interestingly, the lignin oxidation state increased with density in the oxisol. Given the variation in soil character, the consistency in these trends it

  3. Dynamic fractionation of trace metals in soil and sediment samples using rotating coiled column extraction and sequential injection microcolumn extraction: a comparative study.

    PubMed

    Rosende, Maria; Savonina, Elena Yu; Fedotov, Petr S; Miró, Manuel; Cerdà, Víctor; Wennrich, Rainer

    2009-09-15

    Dynamic fractionation has been recognized as an appealing alternative to conventional equilibrium-based sequential extraction procedures (SEPs) for partitioning of trace elements (TE) in environmental solid samples. This paper reports the first attempt for harmonization of flow-through dynamic fractionation using two novel methods, the so-called sequential injection microcolumn (SIMC) extraction and rotating coiled column (RCC) extraction. In SIMC extraction, a column packed with the solid sample is clustered in a sequential injection system, while in RCC, the particulate matter is retained under the action of centrifugal forces. In both methods, the leachants are continuously pumped through the solid substrates by the use of either peristaltic or syringe pumps. A five-step SEP was selected for partitioning of Cu, Pb and Zn in water soluble/exchangeable, acid-soluble, easily reducible, easily oxidizable and moderately reducible fractions from 0.2 to 0.5 g samples at an extractant flow rate of 1.0 mL min(-1) prior to leachate analysis by inductively coupled plasma-atomic emission spectrometry. Similarities and discrepancies between both dynamic approaches were ascertained by fractionation of TE in certified reference materials, namely, SRM 2711 Montana Soil and GBW 07311 sediment, and two real soil samples as well. Notwithstanding the different extraction conditions set by both methods, similar trends of metal distribution were in generally found. The most critical parameters for reliable assessment of mobilizable pools of TE in worse-case scenarios are the size-distribution of sample particles, the density of particles, the content of organic matter and the concentration of major elements. For reference materials and a soil rich in organic matter, the extraction in RCC results in slightly higher recoveries of environmentally relevant fractions of TE, whereas SIMC leaching is more effective for calcareous soils. PMID:19615513

  4. The sequential encoding of competing action goals involves dynamic restructuring of motor plans in working memory.

    PubMed

    Gallivan, Jason P; Bowman, Natasha A R; Chapman, Craig S; Wolpert, Daniel M; Flanagan, J Randall

    2016-06-01

    Recent neural and behavioral findings provide support for the influential idea that in situations in which multiple action options are presented simultaneously, we prepare action plans for each competing option before deciding between and executing one of those plans. However, in natural, everyday environments, our available action options frequently change from one moment to the next, and there is often uncertainty as to whether additional options will become available before having to select a particular course of action. Here, with the use of a target-directed reaching task, we show that in this situation, the brain specifies a competing action for each new, sequentially presented potential target and that recently formed action plans can be revisited and updated so as to conform with separate, more newly developed, plans. These findings indicate that the brain forms labile motor plans for sequentially arising target options that can be flexibly restructured to accommodate new motor plans. PMID:27030738

  5. Portable sequential multicolor thermal imager based on a MCT 384 x 288 focal plane array

    NASA Astrophysics Data System (ADS)

    Breiter, Rainer; Cabanski, Wolfgang A.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann

    2001-10-01

    AIM has developed a sequential multicolor thermal imager to provide customers with a test system to realize real-time spectral selective thermal imaging. In contrast to existing PC based laboratory units, the system is miniaturized with integrated signal processing like non-uniformity correction and post processing functions such as image subtraction of different colors to allow field tests in military applications like detection of missile plumes or camouflaged targets as well as commercial applications like detection of chemical agents, pollution control, etc. The detection module used is a 384 X 288 mercury cadmium telluride (MCT) focal plane array (FPA) available in the mid wave (MWIR) or long wave spectral band LWIR). A compact command and control electronics (CCE) provides clock and voltage supply for the detector as well as 14 bit deep digital conversion of the analog detector output. A continuous rotating wheel with four facets for filters provides spectral selectivity. The customer can choose between various types of filter characteristics, e.g. a 4.2 micrometer bandpass filter for CO2 detection in the MWIR band. The rotating wheel can be synchronized to an external source giving the rotation speed, typical 25 l/s. A position sensor generates the four frame start signals for synchronous operation of the detector -- 100 Hz framerate for the four frames per rotation. The rotating wheel is exchangeable for different configurations and also plates for a microscanner operation to improve geometrical resolution are available instead of a multicolor operation. AIM's programmable MVIP image processing unit is used for signal processing like non- uniformity correction and controlling the detector parameters. The MVIP allows to output the four subsequent images as four quarters of the video screen to prior to any observation task set the integration time for each color individually for comparable performance in each spectral color and after that also to determine

  6. Plane-based sampling for ray casting algorithm in sequential medical images.

    PubMed

    Lin, Lili; Chen, Shengyong; Shao, Yan; Gu, Zichun

    2013-01-01

    This paper proposes a plane-based sampling method to improve the traditional Ray Casting Algorithm (RCA) for the fast reconstruction of a three-dimensional biomedical model from sequential images. In the novel method, the optical properties of all sampling points depend on the intersection points when a ray travels through an equidistant parallel plan cluster of the volume dataset. The results show that the method improves the rendering speed at over three times compared with the conventional algorithm and the image quality is well guaranteed. PMID:23424608

  7. Comprehensive Risk-Based Diagnostically Driven Treatment Planning: Developing Sequentially Generated Treatment.

    PubMed

    Kois, Dean E; Kois, John C

    2015-07-01

    The clinical example presented in this article demonstrates a risk-based, diagnostically driven treatment planning approach by focusing on 4 key categories: periodontal, biomechanical, functional, dentofacial. In addition, our unique approach allowed the comprehensive clinical management of a patient with complex restorative needs. A full-mouth rehabilitation was completed sequentially without sacrificing the amount of dentistry necessary to restore health, comfort, function, and esthetics. The result exceeded the patient's expectation and was made financially possible by extending treatment over numerous years. PMID:26140967

  8. Sequential Model-Based Parameter Optimization: an Experimental Investigation of Automated and Interactive Approaches

    NASA Astrophysics Data System (ADS)

    Hutter, Frank; Bartz-Beielstein, Thomas; Hoos, Holger H.; Leyton-Brown, Kevin; Murphy, Kevin P.

    This work experimentally investigates model-based approaches for optimizing the performance of parameterized randomized algorithms. Such approaches build a response surface model and use this model for finding good parameter settings of the given algorithm. We evaluated two methods from the literature that are based on Gaussian process models: sequential parameter optimization (SPO) (Bartz-Beielstein et al. 2005) and sequential Kriging optimization (SKO) (Huang et al. 2006). SPO performed better "out-of-the-box," whereas SKO was competitive when response values were log transformed. We then investigated key design decisions within the SPO paradigm, characterizing the performance consequences of each. Based on these findings, we propose a new version of SPO, dubbed SPO+, which extends SPO with a novel intensification procedure and a log-transformed objective function. In a domain for which performance results for other (modelfree) parameter optimization approaches are available, we demonstrate that SPO+ achieves state-of-the-art performance. Finally, we compare this automated parameter tuning approach to an interactive, manual process that makes use of classical

  9. Auditory-induced neural dynamics in sensory-motor circuitry predict learned temporal and sequential statistics of birdsong

    PubMed Central

    Bouchard, Kristofer E.; Brainard, Michael S.

    2016-01-01

    Predicting future events is a critical computation for both perception and behavior. Despite the essential nature of this computation, there are few studies demonstrating neural activity that predicts specific events in learned, probabilistic sequences. Here, we test the hypotheses that the dynamics of internally generated neural activity are predictive of future events and are structured by the learned temporal–sequential statistics of those events. We recorded neural activity in Bengalese finch sensory-motor area HVC in response to playback of sequences from individuals’ songs, and examined the neural activity that continued after stimulus offset. We found that the strength of response to a syllable in the sequence depended on the delay at which that syllable was played, with a maximal response when the delay matched the intersyllable gap normally present for that specific syllable during song production. Furthermore, poststimulus neural activity induced by sequence playback resembled the neural response to the next syllable in the sequence when that syllable was predictable, but not when the next syllable was uncertain. Our results demonstrate that the dynamics of internally generated HVC neural activity are predictive of the learned temporal–sequential structure of produced song and that the strength of this prediction is modulated by uncertainty. PMID:27506786

  10. Exposure assessment of mobile phone base station radiation in an outdoor environment using sequential surrogate modeling.

    PubMed

    Aerts, Sam; Deschrijver, Dirk; Joseph, Wout; Verloock, Leen; Goeminne, Francis; Martens, Luc; Dhaene, Tom

    2013-05-01

    Human exposure to background radiofrequency electromagnetic fields (RF-EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF-EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04 km(2) for Global System for Mobile Communications (GSM) technology at 900 MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling. PMID:23315952

  11. Sequential fuzzy diagnosis method for motor roller bearing in variable operating conditions based on vibration analysis.

    PubMed

    Li, Ke; Ping, Xueliang; Wang, Huaqing; Chen, Peng; Cao, Yi

    2013-01-01

    A novel intelligent fault diagnosis method for motor roller bearings which operate under unsteady rotating speed and load is proposed in this paper. The pseudo Wigner-Ville distribution (PWVD) and the relative crossing information (RCI) methods are used for extracting the feature spectra from the non-stationary vibration signal measured for condition diagnosis. The RCI is used to automatically extract the feature spectrum from the time-frequency distribution of the vibration signal. The extracted feature spectrum is instantaneous, and not correlated with the rotation speed and load. By using the ant colony optimization (ACO) clustering algorithm, the synthesizing symptom parameters (SSP) for condition diagnosis are obtained. The experimental results shows that the diagnostic sensitivity of the SSP is higher than original symptom parameter (SP), and the SSP can sensitively reflect the characteristics of the feature spectrum for precise condition diagnosis. Finally, a fuzzy diagnosis method based on sequential inference and possibility theory is also proposed, by which the conditions of the machine can be identified sequentially as well. PMID:23793021

  12. Sequential Fuzzy Diagnosis Method for Motor Roller Bearing in Variable Operating Conditions Based on Vibration Analysis

    PubMed Central

    Li, Ke; Ping, Xueliang; Wang, Huaqing; Chen, Peng; Cao, Yi

    2013-01-01

    A novel intelligent fault diagnosis method for motor roller bearings which operate under unsteady rotating speed and load is proposed in this paper. The pseudo Wigner-Ville distribution (PWVD) and the relative crossing information (RCI) methods are used for extracting the feature spectra from the non-stationary vibration signal measured for condition diagnosis. The RCI is used to automatically extract the feature spectrum from the time-frequency distribution of the vibration signal. The extracted feature spectrum is instantaneous, and not correlated with the rotation speed and load. By using the ant colony optimization (ACO) clustering algorithm, the synthesizing symptom parameters (SSP) for condition diagnosis are obtained. The experimental results shows that the diagnostic sensitivity of the SSP is higher than original symptom parameter (SP), and the SSP can sensitively reflect the characteristics of the feature spectrum for precise condition diagnosis. Finally, a fuzzy diagnosis method based on sequential inference and possibility theory is also proposed, by which the conditions of the machine can be identified sequentially as well. PMID:23793021

  13. A simple, universal, efficient PCR-based gene synthesis method: sequential OE-PCR gene synthesis.

    PubMed

    Zhang, Pingping; Ding, Yingying; Liao, Wenting; Chen, Qiuli; Zhang, Huaqun; Qi, Peipei; He, Ting; Wang, Jinhong; Deng, Songhua; Pan, Tianyue; Ren, Hao; Pan, Wei

    2013-07-25

    Herein we present a simple, universal, efficient gene synthesis method based on sequential overlap extension polymerase chain reactions (OE-PCRs). This method involves four key steps: (i) the design of paired complementary 54-mer oligonucleotides with 18 bp overlaps, (ii) the utilisation of sequential OE-PCR to synthesise full-length genes, (iii) the cloning and sequencing of four positive T-clones of the synthesised genes and (iv) the resynthesis of target genes by OE-PCR with correct templates. Mispriming and secondary structure were found to be the principal obstacles preventing successful gene synthesis and were easily identified and solved in this method. Compensating for the disadvantages of being laborious and time-consuming, this method has many attractive advantages, such as the ability to guarantee successful gene synthesis in most cases and good allowance for Taq polymerase, oligonucleotides, PCR conditions and a high error rate. Thus, this method provides an alternative tool for individual gene synthesis without strict needs of the high-specialised experience. PMID:23597923

  14. Complexity-Measure-Based Sequential Hypothesis Testing for Real-Time Detection of Lethal Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Chen, Szi-Wen

    2006-12-01

    A novel approach that employs a complexity-based sequential hypothesis testing (SHT) technique for real-time detection of ventricular fibrillation (VF) and ventricular tachycardia (VT) is presented. A dataset consisting of a number of VF and VT electrocardiogram (ECG) recordings drawn from the MIT-BIH database was adopted for such an analysis. It was split into two smaller datasets for algorithm training and testing, respectively. Each ECG recording was measured in a 10-second interval. For each recording, a number of overlapping windowed ECG data segments were obtained by shifting a 5-second window by a step of 1 second. During the windowing process, the complexity measure (CM) value was calculated for each windowed segment and the task of pattern recognition was then sequentially performed by the SHT procedure. A preliminary test conducted using the database produced optimal overall predictive accuracy of[InlineEquation not available: see fulltext.]. The algorithm was also implemented on a commercial embedded DSP controller, permitting a hardware realization of real-time ventricular arrhythmia detection.

  15. Bismaleimide and cyanate ester based sequential interpenetrating polymer networks for high temperature application

    NASA Astrophysics Data System (ADS)

    Geng, Xing

    2005-07-01

    A research area of high activity in connection with aerospace engineering has been the development of polymer thermosetting resins that can withstand temperature as high as 300°C while maintaining adequate toughness and providing ease of processing to enable low temperature and low cost composite fabrication methods. In order to meet such requirements, sequential interpenetrating polymer networks (IPNs) based on bismaleimide (BMI) and cyanate ester (CE) monomers were investigated. In these systems, a polycyanurate network is first formed in the presence of BMI and appropriate reactive diluent monomers and, in a second step, a network based on the BMI is created in the presence of a fully formed polycyanurate network. The materials developed can be processed at relatively low temperature (<150°C) and with the aid of electron beam (EB) curing. Of major importance to the success of this work was the identification of a reactive diluent that improves ease of processing and has tailored reactivity to allow for the controlled synthesis of CE-BMI sequential IPNs. Based on solubility and reactivity of a number of reactive diluents, N-acryloylmorpholine (AMP) was selected as a co-monomer for BMI copolymerization. A donor-acceptor reaction mechanism was suggested to explain the relative reactivity of a variety of reactive diluents towards maleimide functionality. The optimum processing parameters for the formation of the first network were determined through the study of metal catalyzed cure and hydrolysis of cyanate esters, whereas the reaction behavior for second network formation in terms of the influence of EB dose rate and temperature was elucidated through an in-situ kinetics study of maleimide and AMP copolymerization. Structure-property relationships were developed which allowed for the design of improved resin systems. In particular, an appropriate network coupler possessing cyanate ester and maleimide functionality was synthesized to link the polycyanurate first

  16. Characterization of deep aquifer dynamics using principal component analysis of sequential multilevel data

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Netzer, L.; Weisbrod, N.; Nasser, A.; Graber, E. R.; Ronen, D.

    2012-03-01

    Two sequential multilevel profiles were obtained in an observation well opened to a 130-m thick, unconfined, contaminated aquifer in Tel Aviv, Israel. While the general profile characteristics of major ions, trace elements, and volatile organic compounds were maintained in the two sampling campaigns conducted 295 days apart, the vertical locations of high concentration gradients were shifted between the two profiles. Principal component analysis (PCA) of the chemical variables resulted in a first principal component which was responsible for ∼60% of the variability, and was highly correlated with depth. PCA revealed three distinct depth-dependent water bodies in both multilevel profiles, which were found to have shifted vertically between the sampling events. This shift cut across a clayey bed which separated the top and intermediate water bodies in the first profile, and was located entirely within the intermediate water body in the second profile. Continuous electrical conductivity monitoring in a packed-off section of the observation well revealed an event in which a distinct water body flowed through the monitored section (v ∼ 150 m yr-1). It was concluded that the observed changes in the profiles result from dominantly lateral flow of water bodies in the aquifer rather than vertical flow. The significance of this study is twofold: (a) it demonstrates the utility of sequential multilevel observations from deep wells and the efficacy of PCA for evaluating the data; (b) the fact that distinct water bodies of 10 to 100 m vertical and horizontal dimensions flow under contaminated sites, which has implications for monitoring and remediation.

  17. Regeneration of strong-base anion-exchange resins by sequential chemical displacement

    SciTech Connect

    Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V.

    2002-01-01

    A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.

  18. Sequential Model Selection based Segmentation to Detect DNA Copy Number Variation

    PubMed Central

    Hu, Jianhua; Zhang, Liwen; Wang, Huixia Judy

    2016-01-01

    Summary Array-based CGH experiments are designed to detect genomic aberrations or regions of DNA copy-number variation that are associated with an outcome, typically a state of disease. Most of the existing statistical methods target on detecting DNA copy number variations in a single sample or array. We focus on the detection of group effect variation, through simultaneous study of multiple samples from multiple groups. Rather than using direct segmentation or smoothing techniques, as commonly seen in existing detection methods, we develop a sequential model selection procedure that is guided by a modified Bayesian information criterion. This approach improves detection accuracy by accumulatively utilizing information across contiguous clones, and has computational advantage over the existing popular detection methods. Our empirical investigation suggests that the performance of the proposed method is superior to that of the existing detection methods, in particular, in detecting small segments or separating neighboring segments with differential degrees of copy-number variation. PMID:26954760

  19. Automated IR determination of petroleum products in water based on sequential injection analysis.

    PubMed

    Falkova, Marina; Vakh, Christina; Shishov, Andrey; Zubakina, Ekaterina; Moskvin, Aleksey; Moskvin, Leonid; Bulatov, Andrey

    2016-02-01

    The simple and easy performed automated method for the IR determination of petroleum products (PP) in water using extraction-chromatographic cartridges has been developed. The method assumes two stages: on-site extraction of PP during a sampling by using extraction-chromatographic cartridges and subsequent determination of the extracted PP using sequential injection analysis (SIA) with IR detection. The appropriate experimental conditions for extraction of the dissolved in water PP and for automated SIA procedure were investigated. The calibration plot constructed using the developed procedure was linear in the range of 3-200 μg L(-1). The limit of detection (LOD), calculated from a blank test based on 3σ was 1 µg L(-1). The sample volume was 1L. The system throughput was found to be 12 h(-1). PMID:26653498

  20. Conversion of lignocellulosic biomass into its molecular components by sequential combination of organic acid and base

    NASA Astrophysics Data System (ADS)

    Noda, Yu

    The primary objective of this research is to explore a new concept of converting lignocellulosic biomass into liquid organic products via hydrolysis by sequentially combining acid and base treatments. The concept was examined by studying two-step hydrolytic reactions of biomass (spruce) using oxialic acid (OA) and tetramethylammonium hydroxide (TMAH) at moderate reaction temperatures below 200 °C. Different selectivity of C-O bond cleavage of hemicellulose, cellulose, and lignin between the reactions with OA and TMAH was demonstrated, and the sequential combination of OA and TMAH treatments exhibited an enhancing effect on conversion of biomass, which proves the promise of the proposed concept. A similar enhancing effect of combination was further confirmed in the reactions with mineral acid and base. Interestingly, characterization of solid residue from reactions of biomass and further investigation of the reactions of commercial cellulose revealed that the A-B sequence (the first reaction with OA and the second with TMAH) enhanced the conversion of cellulose at the second step with TMAH. It was suggested from the NMR and XRD study of solid residues that this enhancement was caused by the reduction of crystallinity of cellulose by the first reaction with OA. This effect was shown to be an interesting feature of A-B treatment sequence for converting lignocellulosic biomass. To improve the yield of monomeric sugars, the effect of adding organic solvents to the system was also studied. No improvement on sugar yield was observed under the explored conditions. However, it was shown that some furans and phenols can be directly formed from the reactions of biomass in the binary solvent system, which may be beneficial for producing more value-added chemicals from biomass.

  1. Physical properties of sequential interpenetrating polymer networks produced from canola oil-based polyurethane and poly(methyl methacrylate).

    PubMed

    Kong, Xiaohua; Narine, Suresh S

    2008-05-01

    Sequential interpenetrating polymer networks (IPNs) were prepared using polyurethane (PUR) synthesized from canola oil-based polyol with terminal primary functional groups and poly(methyl methacrylate) (PMMA). The properties of the material were evaluated by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and modulated differential scanning calorimetry (MDSC), as well as tensile properties measurements. The morphology of the IPNs was investigated using scanning electron microscopy (SEM) and MDSC. A five-phase morphology, that is, sol phase, PUR-rich phase, PUR-rich interphase, PMMA-rich interphase, and PMMA-rich phase, was observed for all the IPNs by applying a new quantitative method based on the measurement of the differential of reversing heat capacity versus temperature from MDSC, although not confirmed by SEM, most likely due to resolution restrictions. NCO/OH molar ratios (cross-linking density) and compositional variations of PUR/PMMA both affected the thermal properties and phase behaviors of the IPNs. Higher degrees of mixing occurred for the IPN with higher NCO/OH molar ratio (2.0/1.0) at PUR concentration of 25 wt %, whereas for the IPN with lower NCO/OH molar ratio (1.6/1.0), higher degrees of mixing occurred at PUR concentration of 35 wt %. The mechanical properties of the IPNs were superior to those of the constituent polymers due to the finely divided rubber and plastic combination structures in these IPNs. PMID:18410139

  2. Sequentially aerated membrane biofilm reactors for autotrophic nitrogen removal: microbial community composition and dynamics

    PubMed Central

    Pellicer-Nàcher, Carles; Franck, Stéphanie; Gülay, Arda; Ruscalleda, Maël; Terada, Akihiko; Al-Soud, Waleed Abu; Hansen, Martin Asser; Sørensen, Søren J; Smets, Barth F

    2014-01-01

    Membrane-aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration can bring the rapid and long-term suppression of NOB and the onset of the activity of anaerobic ammonium oxidizing bacteria (AnAOB). Real-time quantitative polymerase chain reaction analyses confirmed that such shift in performance was mirrored by a change in population densities, with a very drastic reduction of the NOB Nitrospira and Nitrobacter and a 10-fold increase in AnAOB numbers. The study of biofilm sections with relevant 16S rRNA fluorescent probes revealed strongly stratified biofilm structures fostering aerobic ammonium oxidizing bacteria (AOB) in biofilm areas close to the membrane surface (rich in oxygen) and AnAOB in regions neighbouring the liquid phase. Both communities were separated by a transition region potentially populated by denitrifying heterotrophic bacteria. AOB and AnAOB bacterial groups were more abundant and diverse than NOB, and dominated by the r-strategists Nitrosomonas europaea and Ca. Brocadia anammoxidans, respectively. Taken together, the present work presents tools to better engineer, monitor and control the microbial communities that support robust, sustainable and efficient nitrogen removal. PMID:24112350

  3. Sequentially aerated membrane biofilm reactors for autotrophic nitrogen removal: microbial community composition and dynamics.

    PubMed

    Pellicer-Nàcher, Carles; Franck, Stéphanie; Gülay, Arda; Ruscalleda, Maël; Terada, Akihiko; Al-Soud, Waleed Abu; Hansen, Martin Asser; Sørensen, Søren J; Smets, Barth F

    2014-01-01

    Membrane-aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration can bring the rapid and long-term suppression of NOB and the onset of the activity of anaerobic ammonium oxidizing bacteria (AnAOB). Real-time quantitative polymerase chain reaction analyses confirmed that such shift in performance was mirrored by a change in population densities, with a very drastic reduction of the NOB Nitrospira and Nitrobacter and a 10-fold increase in AnAOB numbers. The study of biofilm sections with relevant 16S rRNA fluorescent probes revealed strongly stratified biofilm structures fostering aerobic ammonium oxidizing bacteria (AOB) in biofilm areas close to the membrane surface (rich in oxygen) and AnAOB in regions neighbouring the liquid phase. Both communities were separated by a transition region potentially populated by denitrifying heterotrophic bacteria. AOB and AnAOB bacterial groups were more abundant and diverse than NOB, and dominated by the r-strategists Nitrosomonas europaea and Ca. Brocadia anammoxidans, respectively. Taken together, the present work presents tools to better engineer, monitor and control the microbial communities that support robust, sustainable and efficient nitrogen removal. PMID:24112350

  4. Quantifying subpopulation synergy for antibiotic combinations via mechanism-based modeling and a sequential dosing design.

    PubMed

    Landersdorfer, Cornelia B; Ly, Neang S; Xu, Hongmei; Tsuji, Brian T; Bulitta, Jürgen B

    2013-05-01

    Quantitative modeling of combination therapy can describe the effects of each antibiotic against multiple bacterial populations. Our aim was to develop an efficient experimental and modeling strategy that evaluates different synergy mechanisms using a rapidly killing peptide antibiotic (nisin) combined with amikacin or linezolid as probe drugs. Serial viable counts over 48 h were obtained in time-kill experiments with all three antibiotics in monotherapy against a methicillin-resistant Staphylococcus aureus USA300 strain (inoculum, 10(8) CFU/ml). A sequential design (initial dosing of 8 or 32 mg/liter nisin, switched to amikacin or linezolid at 1.5 h) assessed the rate of killing by amikacin and linezolid against nisin-intermediate and nisin-resistant populations. Simultaneous combinations were additionally studied and all viable count profiles comodeled in S-ADAPT and NONMEM. A mechanism-based model with six populations (three for nisin times two for amikacin) yielded unbiased and precise (r = 0.99, slope = 1.00; S-ADAPT) individual fits. The second-order killing rate constants for nisin against the three populations were 5.67, 0.0664, and 0.00691 liter/(mg · h). For amikacin, the maximum killing rate constants were 10.1 h(-1) against its susceptible and 0.771 h(-1) against its less-susceptible populations, with 14.7 mg/liter amikacin causing half-maximal killing. After incorporating the effects of nisin and amikacin against each population, no additional synergy function was needed. Linezolid inhibited successful bacterial replication but did not efficiently kill populations less susceptible to nisin. Nisin plus amikacin achieved subpopulation synergy. The proposed sequential and simultaneous dosing design offers an efficient approach to quantitatively characterize antibiotic synergy over time and prospectively evaluate antibiotic combination dosing strategies. PMID:23478962

  5. An automatic system for acidity determination based on sequential injection titration and the monosegmented flow approach.

    PubMed

    Kozak, Joanna; Wójtowicz, Marzena; Gawenda, Nadzieja; Kościelniak, Paweł

    2011-06-15

    An automatic sequential injection system, combining monosegmented flow analysis, sequential injection analysis and sequential injection titration is proposed for acidity determination. The system enables controllable sample dilution and generation of standards of required concentration in a monosegmented sequential injection manner, sequential injection titration of the prepared solutions, data collecting, and handling. It has been tested on spectrophotometric determination of acetic, citric and phosphoric acids with sodium hydroxide used as a titrant and phenolphthalein or thymolphthalein (in the case of phosphoric acid determination) as indicators. Accuracy better than |4.4|% (RE) and repeatability better than 2.9% (RSD) have been obtained. It has been applied to the determination of total acidity in vinegars and various soft drinks. The system provides low sample (less than 0.3 mL) consumption. On average, analysis of a sample takes several minutes. PMID:21641455

  6. Sequential addition of aprepitant in patients receiving carboplatin-based chemotherapy.

    PubMed

    Suzuki, Seiichiro; Karayama, Masato; Inui, Naoki; Kuroishi, Shigeki; Fujisawa, Tomoyuki; Enomoto, Noriyuki; Nakamura, Yutaro; Yokomura, Koshi; Toyoshima, Mikio; Imokawa, Shiro; Asada, Kazuhiro; Masuda, Masafumi; Yamada, Takashi; Watanabe, Hiroshi; Hayakawa, Hiroshi; Suda, Takafumi

    2016-07-01

    Chemotherapy-induced nausea and vomiting is a challenging issue. Although aprepitant is sometimes used as a therapeutic option in patients receiving moderately emetogenic chemotherapy, the potential benefit of sequential addition of aprepitant to dexamethasone and a 5-hydroxytryptamine-3 (5-HT3) receptor antagonist during the second cycle of carboplatin-based chemotherapy remains unclear. Chemo-naïve patients with advanced non-small cell lung cancer (NSCLC) who received carboplatin-based chemotherapy were treated with doublet antiemetic therapy with dexamethasone and a 5-HT3 receptor antagonist during the first cycle of chemotherapy. Aprepitant was then added during the second cycle of chemotherapy. The primary endpoint was overall complete response rate, defined as no vomiting and no rescue therapy during the 120 h after administration of chemotherapy. Sixty-seven patients were enrolled, 63 of whom were eligible after two cycles of chemotherapy. The overall complete response rate was significantly improved in the second cycle [87.3 %, 95 % confidence interval (CI) 76.5-94.4 %] compared with the first cycle (65.1 %, 95 % CI 52.0-76.7 %; p < 0.001). Improvement was observed in the delayed phase, but not in the acute phase. Subsequent addition of aprepitant significantly improved the overall complete response rate in NSCLC patients receiving a second cycle of carboplatin-based chemotherapy. PMID:27235141

  7. How Cognitive Styles Affect the Learning Behaviors of Online Problem-Solving Based Discussion Activity: A Lag Sequential Analysis

    ERIC Educational Resources Information Center

    Wu, Sheng-Yi; Hou, Huei-Tse

    2015-01-01

    Cognitive styles play an important role in influencing the learning process, but to date no relevant study has been conducted using lag sequential analysis to assess knowledge construction learning patterns based on different cognitive styles in computer-supported collaborative learning activities in online collaborative discussions. This study…

  8. Sequential UV- and chlorine-based disinfection to mitigate Escherichia coli in drinking water biofilms.

    PubMed

    Murphy, H M; Payne, S J; Gagnon, G A

    2008-04-01

    This study was designed to examine the potential downstream benefits of sequential disinfection to control the persistence of Escherichia coli under conditions relevant to drinking water distribution systems. Eight annular reactors (four polycarbonate and four cast iron) were setup in parallel to address various factors that could influence biofilm growth in distribution systems. Eight reactors were treated with chlorine, chlorine dioxide and monochloramine alone or in combination with UV to examine the effects on Escherichia coli growth and persistence in both the effluent and biofilm. In general, UV-treated systems in combination with chlorine or chlorine dioxide and monochloramine achieved greater log reductions in both effluent and biofilm than systems treated with chlorine-based disinfectants alone. However, during UV-low chlorine disinfection, E. coli was found to persist at low levels, suggesting that the UV treatment had instigated an adaptive mutation. During UV-chlorine-dioxide treatment, the E. coli that was initially below the detection limit reappeared during a low level of disinfection (0.2 mg/L) in the cast iron systems. Chloramine was shown to be effective in disinfecting suspended E. coli in the effluent but was unable to reduce biofilm counts to below the detection limit. Issues such as repair mechanism of E. coli and nitrification could help explain some of these aberrations. Improved understanding of the ability of chlorine-based disinfectant in combination with UV to provide sufficient disinfection will ultimately effect in improved management and safety of drinking water. PMID:18242660

  9. Using sequential Gaussian simulation to quantify uncertainties in interpolated gauge based precipitation

    NASA Astrophysics Data System (ADS)

    Ehlers, Lennart; Refsgaard, Jens Christian; Sonnenborg, Torben O.; He, Xin; Jensen, Karsten H.

    2016-04-01

    Precipitation is a key input to hydrological models. Spatially distributed rainfall used in hydrological modelling is commonly based on the interpolation of gauge rainfall using conventional geostatistical techniques such as kriging, e.g. Salamon and Feyen [2009], Stisen et al. [2011]. While being effective point interpolators [Moulin et al., 2009], these techniques are unable to reproduce the spatial variability inherent in the rainfall process at unsampled locations. Stochastic simulation approaches provide the means to better capture this variability and hence to quantify the associated spatial uncertainty [McMillan et al., 2011]. The objective of this study is to quantify uncertainties in interpolated gauge based rainfall by employing sequential Gaussian simulation (SGS) coupled with ordinary kriging (OK) to generate realizations of daily precipitation at a 2x2 km2 grid. The rainfall gauge data was collected in a 1055 km2 subcatchment within the HOBE catchment (Jutland, Denmark) [Jensen and Illangasekare, 2011]. The following uncertainties are considered: i) interpolation uncertainty ii) uncertainty on the point measurement iii) location uncertainty. Results from using different numbers of SGS realizations and different lengths of the simulated period as well as different assumptions on the underlying uncertainties will be presented and discussed with regard to mean annual catchment rainfall. Jensen, K. H., and T. H. Illangasekare (2011), HOBE: A Hydrological Observatory, Vadose Zone J, 10(1), 1-7. McMillan, H., B. Jackson, M. Clark, D. Kavetski, and R. Woods (2011), Rainfall uncertainty in hydrological modelling: An evaluation of multiplicative error models, J Hydrol, 400(1-2), 83-94. Moulin, L., E. Gaume, and C. Obled (2009), Uncertainties on mean areal precipitation: assessment and impact on streamflow simulations, Hydrol Earth Syst Sc, 13(2), 99-114. Salamon, P., and L. Feyen (2009), Assessing parameter, precipitation, and predictive uncertainty in a

  10. Robust sequential working memory recall in heterogeneous cognitive networks

    PubMed Central

    Rabinovich, Mikhail I.; Sokolov, Yury; Kozma, Robert

    2014-01-01

    Psychiatric disorders are often caused by partial heterogeneous disinhibition in cognitive networks, controlling sequential and spatial working memory (SWM). Such dynamic connectivity changes suggest that the normal relationship between the neuronal components within the network deteriorates. As a result, competitive network dynamics is qualitatively altered. This dynamics defines the robust recall of the sequential information from memory and, thus, the SWM capacity. To understand pathological and non-pathological bifurcations of the sequential memory dynamics, here we investigate the model of recurrent inhibitory-excitatory networks with heterogeneous inhibition. We consider the ensemble of units with all-to-all inhibitory connections, in which the connection strengths are monotonically distributed at some interval. Based on computer experiments and studying the Lyapunov exponents, we observed and analyzed the new phenomenon—clustered sequential dynamics. The results are interpreted in the context of the winnerless competition principle. Accordingly, clustered sequential dynamics is represented in the phase space of the model by two weakly interacting quasi-attractors. One of them is similar to the sequential heteroclinic chain—the regular image of SWM, while the other is a quasi-chaotic attractor. Coexistence of these quasi-attractors means that the recall of the normal information sequence is intermittently interrupted by episodes with chaotic dynamics. We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions. PMID:25452717

  11. Glycogenome expression dynamics during mouse C2C12 myoblast differentiation suggests a sequential reorganization of membrane glycoconjugates

    PubMed Central

    Janot, Mathilde; Audfray, Aymeric; Loriol, Céline; Germot, Agnès; Maftah, Abderrahman; Dupuy, Fabrice

    2009-01-01

    Background Several global transcriptomic and proteomic approaches have been applied in order to obtain new molecular insights on skeletal myogenesis, but none has generated any specific data on glycogenome expression, and thus on the role of glycan structures in this process, despite the involvement of glycoconjugates in various biological events including differentiation and development. In the present study, a quantitative real-time RT-PCR technology was used to profile the dynamic expression of 375 glycogenes during the differentiation of C2C12 myoblasts into myotubes. Results Of the 276 genes expressed, 95 exhibited altered mRNA expression when C2C12 cells differentiated and 37 displayed more than 4-fold up- or down-regulations. Principal Component Analysis and Hierarchical Component Analysis of the expression dynamics identified three groups of coordinately and sequentially regulated genes. The first group included 12 down-regulated genes, the second group four genes with an expression peak at 24 h of differentiation, and the last 21 up-regulated genes. These genes mainly encode cell adhesion molecules and key enzymes involved in the biosynthesis of glycosaminoglycans and glycolipids (neolactoseries, lactoseries and ganglioseries), providing a clearer indication of how the plasma membrane and extracellular matrix may be modified prior to cell fusion. In particular, an increase in the quantity of ganglioside GM3 at the cell surface of myoblasts is suggestive of its potential role during the initial steps of myogenic differentiation. Conclusion For the first time, these results provide a broad description of the expression dynamics of glycogenes during C2C12 differentiation. Among the 37 highly deregulated glycogenes, 29 had never been associated with myogenesis. Their biological functions suggest new roles for glycans in skeletal myogenesis. PMID:19843320

  12. A sequential classification rule based on multiple quantitative tests in the absence of a gold standard.

    PubMed

    Zhang, Jingyang; Zhang, Ying; Chaloner, Kathryn; Stapleton, Jack T

    2016-04-15

    In many medical applications, combining information from multiple biomarkers could yield a better diagnosis than any single one on its own. When there is a lack of a gold standard, an algorithm of classifying subjects into the case and non-case status is necessary for combining multiple markers. The aim of this paper is to develop a method to construct a composite test from multiple applicable tests and derive an optimal classification rule under the absence of a gold standard. Rather than combining the tests, we treat the tests as a sequence. This sequential composite test is based on a mixture of two multivariate normal latent models for the distribution of the test results in case and non-case groups, and the optimal classification rule is derived returning the greatest sensitivity at a given specificity. This method is applied to a real-data example and simulation studies have been carried out to assess the statistical properties and predictive accuracy of the proposed composite test. This method is also attainable to implement nonparametrically. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26522690

  13. A Method for Optimizing Lightweight-Gypsum Design Based on Sequential Measurements of Physical Parameters

    NASA Astrophysics Data System (ADS)

    Vimmrová, Alena; Kočí, Václav; Krejsová, Jitka; Černý, Robert

    2016-06-01

    A method for lightweight-gypsum material design using waste stone dust as the foaming agent is described. The main objective is to reach several physical properties which are inversely related in a certain way. Therefore, a linear optimization method is applied to handle this task systematically. The optimization process is based on sequential measurement of physical properties. The results are subsequently point-awarded according to a complex point criterion and new composition is proposed. After 17 trials the final mixture is obtained, having the bulk density equal to (586 ± 19) kg/m3 and compressive strength (1.10 ± 0.07) MPa. According to a detailed comparative analysis with reference gypsum, the newly developed material can be used as excellent thermally insulating interior plaster with the thermal conductivity of (0.082 ± 0.005) W/(m·K). In addition, its practical application can bring substantial economic and environmental benefits as the material contains 25 % of waste stone dust.

  14. Moving Sound Source Localization Based on Sequential Subspace Estimation in Actual Room Environments

    NASA Astrophysics Data System (ADS)

    Tsuji, Daisuke; Suyama, Kenji

    This paper presents a novel method for moving sound source localization and its performance evaluation in actual room environments. The method is based on the MUSIC (MUltiple SIgnal Classification) which is one of the most high resolution localization methods. When using the MUSIC, a computation of eigenvectors of correlation matrix is required for the estimation. It needs often a high computational costs. Especially, in the situation of moving source, it becomes a crucial drawback because the estimation must be conducted at every the observation time. Moreover, since the correlation matrix varies its characteristics due to the spatial-temporal non-stationarity, the matrix have to be estimated using only a few observed samples. It makes the estimation accuracy degraded. In this paper, the PAST (Projection Approximation Subspace Tracking) is applied for sequentially estimating the eigenvectors spanning the subspace. In the PAST, the eigen-decomposition is not required, and therefore it is possible to reduce the computational costs. Several experimental results in the actual room environments are shown to present the superior performance of the proposed method.

  15. A cascading activity-based probe sequentially targets E1-E2-E3 ubiquitin enzymes.

    PubMed

    Mulder, Monique P C; Witting, Katharina; Berlin, Ilana; Pruneda, Jonathan N; Wu, Kuen-Phon; Chang, Jer-Gung; Merkx, Remco; Bialas, Johanna; Groettrup, Marcus; Vertegaal, Alfred C O; Schulman, Brenda A; Komander, David; Neefjes, Jacques; El Oualid, Farid; Ovaa, Huib

    2016-07-01

    Post-translational modifications of proteins with ubiquitin (Ub) and ubiquitin-like modifiers (Ubls), orchestrated by a cascade of specialized E1, E2 and E3 enzymes, control a wide range of cellular processes. To monitor catalysis along these complex reaction pathways, we developed a cascading activity-based probe, UbDha. Similarly to the native Ub, upon ATP-dependent activation by the E1, UbDha can travel downstream to the E2 (and subsequently E3) enzymes through sequential trans-thioesterifications. Unlike the native Ub, at each step along the cascade, UbDha has the option to react irreversibly with active site cysteine residues of target enzymes, thus enabling their detection. We show that our cascading probe 'hops' and 'traps' catalytically active Ub-modifying enzymes (but not their substrates) by a mechanism diversifiable to Ubls. Our founder methodology, amenable to structural studies, proteome-wide profiling and monitoring of enzymatic activity in living cells, presents novel and versatile tools to interrogate Ub and Ubl cascades. PMID:27182664

  16. Location Prediction Based on Transition Probability Matrices Constructing from Sequential Rules for Spatial-Temporal K-Anonymity Dataset

    PubMed Central

    Liu, Zhao; Zhu, Yunhong; Wu, Chenxue

    2016-01-01

    Spatial-temporal k-anonymity has become a mainstream approach among techniques for protection of users’ privacy in location-based services (LBS) applications, and has been applied to several variants such as LBS snapshot queries and continuous queries. Analyzing large-scale spatial-temporal anonymity sets may benefit several LBS applications. In this paper, we propose two location prediction methods based on transition probability matrices constructing from sequential rules for spatial-temporal k-anonymity dataset. First, we define single-step sequential rules mined from sequential spatial-temporal k-anonymity datasets generated from continuous LBS queries for multiple users. We then construct transition probability matrices from mined single-step sequential rules, and normalize the transition probabilities in the transition matrices. Next, we regard a mobility model for an LBS requester as a stationary stochastic process and compute the n-step transition probability matrices by raising the normalized transition probability matrices to the power n. Furthermore, we propose two location prediction methods: rough prediction and accurate prediction. The former achieves the probabilities of arriving at target locations along simple paths those include only current locations, target locations and transition steps. By iteratively combining the probabilities for simple paths with n steps and the probabilities for detailed paths with n-1 steps, the latter method calculates transition probabilities for detailed paths with n steps from current locations to target locations. Finally, we conduct extensive experiments, and correctness and flexibility of our proposed algorithm have been verified. PMID:27508502

  17. Location Prediction Based on Transition Probability Matrices Constructing from Sequential Rules for Spatial-Temporal K-Anonymity Dataset.

    PubMed

    Zhang, Haitao; Chen, Zewei; Liu, Zhao; Zhu, Yunhong; Wu, Chenxue

    2016-01-01

    Spatial-temporal k-anonymity has become a mainstream approach among techniques for protection of users' privacy in location-based services (LBS) applications, and has been applied to several variants such as LBS snapshot queries and continuous queries. Analyzing large-scale spatial-temporal anonymity sets may benefit several LBS applications. In this paper, we propose two location prediction methods based on transition probability matrices constructing from sequential rules for spatial-temporal k-anonymity dataset. First, we define single-step sequential rules mined from sequential spatial-temporal k-anonymity datasets generated from continuous LBS queries for multiple users. We then construct transition probability matrices from mined single-step sequential rules, and normalize the transition probabilities in the transition matrices. Next, we regard a mobility model for an LBS requester as a stationary stochastic process and compute the n-step transition probability matrices by raising the normalized transition probability matrices to the power n. Furthermore, we propose two location prediction methods: rough prediction and accurate prediction. The former achieves the probabilities of arriving at target locations along simple paths those include only current locations, target locations and transition steps. By iteratively combining the probabilities for simple paths with n steps and the probabilities for detailed paths with n-1 steps, the latter method calculates transition probabilities for detailed paths with n steps from current locations to target locations. Finally, we conduct extensive experiments, and correctness and flexibility of our proposed algorithm have been verified. PMID:27508502

  18. Comparison of two ways for representation of the forecast probability density function in ensemble-based sequential data assimilation

    NASA Astrophysics Data System (ADS)

    Nakano, Shinya

    2013-04-01

    In the ensemble-based sequential data assimilation, the probability density function (PDF) at each time step is represented by ensemble members. These ensemble members are usually assumed to be Monte Carlo samples drawn from the PDF, and the probability density is associated with the concentration of the ensemble members. On the basis of the Monte Carlo approximation, the forecast ensemble, which is obtained by applying the dynamical model to each ensemble member, provides an approximation of the forecast PDF on the basis of the Chapman-Kolmogorov integral. In practical cases, however, the ensemble size is limited by available computational resources, and it is typically much less than the system dimension. In such situations, the Monte Carlo approximation would not well work. When the ensemble size is less than the system dimension, the ensemble would form a simplex in a subspace. The simplex can not represent the third or higher-order moments of the PDF, but it can represent only the Gaussian features of the PDF. As noted by Wang et al. (2004), the forecast ensemble, which is obtained by applying the dynamical model to each member of the simplex ensemble, provides an approximation of the mean and covariance of the forecast PDF where the Taylor expansion of the dynamical model up to the second-order is considered except that the uncertainties which can not represented by the ensemble members are ignored. Since the third and higher-order nonlinearity is discarded, the forecast ensemble would provide some bias to the forecast. Using a small nonlinear model, the Lorenz 63 model, we also performed the experiment of the state estimation with both the simplex representation and the Monte Carlo representation, which corresponds to the limited-sized ensemble case and the large-sized ensemble case, respectively. If we use the simplex representation, it is found that the estimates tend to have some bias which is likely to be caused by the nonlinearity of the system rather

  19. Dynamics of changes in electrical activity in the rabbit cerebral cortex during sequential sessions of "animal hypnosis".

    PubMed

    Rusinova, E V; Davydov, V I

    2010-06-01

    The dynamics of changes in individual electrical activity rhythms in the premotor, sensorimotor, and temporal-parietal areas of the cortex in both hemispheres were studied in chronic experiments in rabbits during sequential sessions of "animal hypnosis." These experiments showed that during the first session of "animal hypnosis," significant changes in electrical activity occurred only in the premotor area of the cortex of the right hemisphere, where there were increases in spectral power in the delta-1 and delta-2 ranges and decreases in spectral power in other ranges of electrical activity. Subsequent sessions of "animal hypnosis" formed increasing changes in electrical activity, which were particularly marked in cortical areas in the right hemisphere. Significant changes in spectral power in the delta and theta ranges of electrical activity in cortical areas did not arise at the beginning of the hypnotic state, but after 4-6 min. During the third session of "animal hypnosis," the course of electrical activity in the alpha and beta rhythms in the premotor and sensorimotor areas of the cortex became wave-like in nature. PMID:20490695

  20. Study of ion flow dynamics in an inertial electrostatic confinement device through sequential grid construction

    SciTech Connect

    Murali, S. Krupakar; Kulcinski, G. L.; Santarius, J. F.

    2008-12-15

    Experiments were performed to understand the dynamics of the ion flow in an inertial electrostatic confinement (IEC) device. This was done by monitoring the fusion rate as the symmetry of the grid was increased starting with a single loop all the way until the entire grid is constructed. The fusion rate was observed to increase with grid symmetry and eventually saturate. A single loop grid was observed to generate a cylindrical ({approx}line) fusion source. The ion flow distribution was measured by introducing fine wires across a single loop of the grid in the form of a chord of a circle (chord wires). This study revealed that with increased symmetry of the cathode grid wires the convergence of the ions improves. The chord wires provided electrons for ionization even at low pressures ({approx}6.67 mPa) and helped sustain the plasma. The impinging ions heat these wires locally and the temperature of the wires was measured using an infrared thermometer that was used to understand the ion flow distribution across the cathode grid. The presence of the grid wires seems to affect the fusion rate more drastically than previously thought (was assumed to be uniform around the central grid). Most of the fusion reactions were observed to occur in the ion microchannels that form in gaps between the cathode wires. This work helps understand the fusion source regimes and calibrate the IEC device.

  1. Sequential cytokine dynamics in chronic rejection of rat renal allografts: roles for cytokines RANTES and MCP-1.

    PubMed Central

    Nadeau, K C; Azuma, H; Tilney, N L

    1995-01-01

    Chronic rejection, the most important cause of long-term graft failure, is thought to result from both alloantigen-dependent and -independent factors. To examine these influences, cytokine dynamics were assessed by semiquantitative competitive reverse transcriptase-PCR and by immunohistology in an established rat model of chronic rejection lf renal allografts. Isograft controls develop morphologic and immunohistologic changes that are similar to renal allograft changes, although quantitatively less intense and at a delayed speed; these are thought to occur secondary to antigen-independent events. Sequential cytokine expression was determined throughout the process. During an early reversible allograft rejection episode, both T-cell associated [interleukin (IL) 2, IL-2 receptor, IL-4, and interferon gamma] and macrophage (IL-1 alpha, tumor necrosis factor alpha, and IL-6) products were up-regulated despite transient immunosuppression. RANTES (regulated upon activation, normal T-cell expressed and secreted) peaked at 2 weeks; intercellular adhesion molecule (ICAM-1) was maximally expressed at 6 weeks. Macrophage products such as monocyte chemoattractant protein (MCP-1) increased dramatically (to 10 times), presaging intense peak macrophage infiltration at 16 weeks. In contrast, in isografts, ICAM-1 peaked at 24 weeks. MCP-1 was maximally expressed at 52 weeks, commensurate with a progressive increase in infiltrating macrophages. Cytokine expression in the spleen of allograft and isograft recipients was insignificant. We conclude that chronic rejection of kidney allografts in rats is predominantly a local macrophage-dependent event with intense up-regulation of macrophage products such as MCP-1, IL-6, and inducible nitric oxide synthase. The cytokine expression in isografts emphasizes the contribution of antigen-independent events. The dynamics of RANTES expression between early and late phases of chronic rejection suggest a key role in mediating the events of the

  2. Off-line experiments on radionuclide detection based on the sequential Bayesian approach

    NASA Astrophysics Data System (ADS)

    Qingpei, Xiang; Dongfeng, Tian; Fanhua, Hao; Ge, Ding; Jun, Zeng; Fei, Luo

    2013-11-01

    The sequential Bayesian approach proposed by Candy et al. for radioactive materials detection has aroused increasing interest in radiation detection research and is potentially a useful tool for prevention of the transportation of radioactive materials by terrorists. In our previous work, the performance of the sequential Bayesian approach was studied numerically through a simulation experiment platform. In this paper, a sequential Bayesian processor incorporating a LaBr3(Ce) detector, and using the energy, decay rate and emission probability of the radionuclide, is fully developed. Off-line experiments for the performance of the sequential Bayesian approach in radionuclide detection are developed by placing 60Co, 137Cs, 133Ba and 152Eu at various distances from the front face of the LaBr3(Ce) detector. The off-line experiment results agree well with the results of previous numerical experiments. The maximum detection distance is introduced to evaluate the processor‧s ability to detect radionuclides with a specific level of activity.

  3. MRI Based Preterm White Matter Injury Classification: The Importance of Sequential Imaging in Determining Severity of Injury

    PubMed Central

    Martinez-Biarge, Miriam; Groenendaal, Floris; Kersbergen, Karina J.; Benders, Manon J. N. L.; Foti, Francesca; Cowan, Frances M.; de Vries, Linda S.

    2016-01-01

    Background The evolution of non-hemorrhagic white matter injury (WMI) based on sequential magnetic resonance imaging (MRI) has not been well studied. Our aim was to describe sequential MRI findings in preterm infants with non-hemorrhagic WMI and to develop an MRI classification system for preterm WMI based on these findings. Methods Eighty-two preterm infants (gestation ≤35 weeks) were retrospectively included. WMI was diagnosed and classified based on sequential cranial ultrasound (cUS) and confirmed on MRI. Results 138 MRIs were obtained at three time-points: early (<2 weeks; n = 32), mid (2–6 weeks; n = 30) and term equivalent age (TEA; n = 76). 63 infants (77%) had 2 MRIs during the neonatal period. WMI was non-cystic in 35 and cystic in 47 infants. In infants with cystic-WMI early MRI showed extensive restricted diffusion abnormalities, cysts were already present in 3 infants; mid MRI showed focal or extensive cysts, without acute diffusion changes. A significant reduction in the size and/or extent of the cysts was observed in 32% of the infants between early/mid and TEA MRI. In 4/9 infants previously seen focal cysts were no longer identified at TEA. All infants with cystic WMI showed ≥2 additional findings at TEA: significant reduction in WM volume, mild-moderate irregular ventriculomegaly, several areas of increased signal intensity on T1-weighted-images, abnormal myelination of the PLIC, small thalami. Conclusion In infants with extensive WM cysts at 2–6 weeks, cysts may be reduced in number or may even no longer be seen at TEA. A single MRI at TEA, without taking sequential cUS data and pre-TEA MRI findings into account, may underestimate the extent of WMI; based on these results we propose a new MRI classification for preterm non-hemorrhagic WMI. PMID:27257863

  4. Sequential Application of Ligand and Structure Based Modeling Approaches to Index Chemicals for Their hH4R Antagonism

    PubMed Central

    Basile, Livia; Milardi, Danilo; Zeidan, Mouhammed; Raiyn, Jamal; Guccione, Salvatore; Rayan, Anwar

    2014-01-01

    The human histamine H4 receptor (hH4R), a member of the G-protein coupled receptors (GPCR) family, is an increasingly attractive drug target. It plays a key role in many cell pathways and many hH4R ligands are studied for the treatment of several inflammatory, allergic and autoimmune disorders, as well as for analgesic activity. Due to the challenging difficulties in the experimental elucidation of hH4R structure, virtual screening campaigns are normally run on homology based models. However, a wealth of information about the chemical properties of GPCR ligands has also accumulated over the last few years and an appropriate combination of these ligand-based knowledge with structure-based molecular modeling studies emerges as a promising strategy for computer-assisted drug design. Here, two chemoinformatics techniques, the Intelligent Learning Engine (ILE) and Iterative Stochastic Elimination (ISE) approach, were used to index chemicals for their hH4R bioactivity. An application of the prediction model on external test set composed of more than 160 hH4R antagonists picked from the chEMBL database gave enrichment factor of 16.4. A virtual high throughput screening on ZINC database was carried out, picking ∼4000 chemicals highly indexed as H4R antagonists' candidates. Next, a series of 3D models of hH4R were generated by molecular modeling and molecular dynamics simulations performed in fully atomistic lipid membranes. The efficacy of the hH4R 3D models in discrimination between actives and non-actives were checked and the 3D model with the best performance was chosen for further docking studies performed on the focused library. The output of these docking studies was a consensus library of 11 highly active scored drug candidates. Our findings suggest that a sequential combination of ligand-based chemoinformatics approaches with structure-based ones has the potential to improve the success rate in discovering new biologically active GPCR drugs and increase the

  5. Camera-Based Online Signature Verification with Sequential Marginal Likelihood Change Detector

    NASA Astrophysics Data System (ADS)

    Muramatsu, Daigo; Yasuda, Kumiko; Shirato, Satoshi; Matsumoto, Takashi

    Several online signature verification systems that use cameras have been proposed. These systems obtain online signature data from video images by tracking the pen tip. Such systems are very useful because special devices such as pen-operated digital tablets are not necessary. One drawback, however, is that if the captured images are blurred, pen tip tracking may fail, which causes performance degradation. To solve this problem, here we propose a scheme to detect such images and re-estimate the pen tip position associated with the blurred images. Our pen tracking algorithm is implemented by using the sequential Monte Carlo method, and a sequential marginal likelihood is used for blurred image detection. Preliminary experiments were performed using private data consisting of 390 genuine signatures and 1560 forged signatures. The experimental results show that the proposed algorithm improved performance in terms of verification accuracy.

  6. Determination of ambroxol hydrochloride, methylparaben and benzoic acid in pharmaceutical preparations based on sequential injection technique coupled with monolithic column.

    PubMed

    Satínský, Dalibor; Huclová, Jitka; Ferreira, Raquel L C; Montenegro, Maria Conceição B S M; Solich, Petr

    2006-02-13

    The porous monolithic columns show high performance at relatively low pressure. The coupling of short monoliths with sequential injection technique (SIA) results in a new approach to implementation of separation step to non-separation low-pressure method. In this contribution, a new separation method for simultaneous determination of ambroxol, methylparaben and benzoic acid was developed based on a novel reversed-phase sequential injection chromatography (SIC) technique with UV detection. A Chromolith SpeedROD RP-18e, 50-4.6 mm column with 10 mm precolumn and a FIAlab 3000 system with a six-port selection valve and 5 ml syringe were used for sequential injection chromatographic separations in our study. The mobile phase used was acetonitrile-tetrahydrofuran-0.05M acetic acid (10:10:90, v/v/v), pH 3.75 adjusted with triethylamine, flow rate 0.48 mlmin(-1), UV-detection was at 245 nm. The analysis time was <11 min. A new SIC method was validated and compared with HPLC. The method was found to be useful for the routine analysis of the active compounds ambroxol and preservatives (methylparaben or benzoic acid) in various pharmaceutical syrups and drops. PMID:16165338

  7. A Soft Sensor for Bioprocess Control Based on Sequential Filtering of Metabolic Heat Signals

    PubMed Central

    Paulsson, Dan; Gustavsson, Robert; Mandenius, Carl-Fredrik

    2014-01-01

    Soft sensors are the combination of robust on-line sensor signals with mathematical models for deriving additional process information. Here, we apply this principle to a microbial recombinant protein production process in a bioreactor by exploiting bio-calorimetric methodology. Temperature sensor signals from the cooling system of the bioreactor were used for estimating the metabolic heat of the microbial culture and from that the specific growth rate and active biomass concentration were derived. By applying sequential digital signal filtering, the soft sensor was made more robust for industrial practice with cultures generating low metabolic heat in environments with high noise level. The estimated specific growth rate signal obtained from the three stage sequential filter allowed controlled feeding of substrate during the fed-batch phase of the production process. The biomass and growth rate estimates from the soft sensor were also compared with an alternative sensor probe and a capacitance on-line sensor, for the same variables. The comparison showed similar or better sensitivity and lower variability for the metabolic heat soft sensor suggesting that using permanent temperature sensors of a bioreactor is a realistic and inexpensive alternative for monitoring and control. However, both alternatives are easy to implement in a soft sensor, alone or in parallel. PMID:25264951

  8. Numerical evaluation of sequential bone drilling strategies based on thermal damage.

    PubMed

    Tai, Bruce L; Palmisano, Andrew C; Belmont, Barry; Irwin, Todd A; Holmes, James; Shih, Albert J

    2015-09-01

    Sequentially drilling multiple holes in bone is used clinically for surface preparation to aid in fusion of a joint, typically under non-irrigated conditions. Drilling induces a significant amount of heat and accumulates after multiple passes, which can result in thermal osteonecrosis and various complications. To understand the heat propagation over time, a 3D finite element model was developed to simulate sequential bone drilling. By incorporating proper material properties and a modified bone necrosis criteria, this model can visualize the propagation of damaged areas. For this study, comparisons between a 2.0 mm Kirschner wire and 2.0 mm twist drill were conducted with their heat sources determined using an inverse method and experimentally measured bone temperatures. Three clinically viable solutions to reduce thermally-induced bone damage were evaluated using finite element analysis, including tool selection, time interval between passes, and different drilling sequences. Results show that the ideal solution would be using twist drills rather than Kirschner wires if the situation allows. A shorter time interval between passes was also found to be beneficial as it reduces the total heat exposure time. Lastly, optimizing the drilling sequence reduced the thermal damage of bone, but the effect may be limited. This study demonstrates the feasibility of using the proposed model to study clinical issues and find potential solutions prior to clinical trials. PMID:26163230

  9. A soft sensor for bioprocess control based on sequential filtering of metabolic heat signals.

    PubMed

    Paulsson, Dan; Gustavsson, Robert; Mandenius, Carl-Fredrik

    2014-01-01

    Soft sensors are the combination of robust on-line sensor signals with mathematical models for deriving additional process information. Here, we apply this principle to a microbial recombinant protein production process in a bioreactor by exploiting bio-calorimetric methodology. Temperature sensor signals from the cooling system of the bioreactor were used for estimating the metabolic heat of the microbial culture and from that the specific growth rate and active biomass concentration were derived. By applying sequential digital signal filtering, the soft sensor was made more robust for industrial practice with cultures generating low metabolic heat in environments with high noise level. The estimated specific growth rate signal obtained from the three stage sequential filter allowed controlled feeding of substrate during the fed-batch phase of the production process. The biomass and growth rate estimates from the soft sensor were also compared with an alternative sensor probe and a capacitance on-line sensor, for the same variables. The comparison showed similar or better sensitivity and lower variability for the metabolic heat soft sensor suggesting that using permanent temperature sensors of a bioreactor is a realistic and inexpensive alternative for monitoring and control. However, both alternatives are easy to implement in a soft sensor, alone or in parallel. PMID:25264951

  10. Preparation of 2,3-Disubstituted Indoles by Sequential Larock Heteroannulation and Silicon-Based Cross-Coupling Reactions

    PubMed Central

    Baird, John D.

    2009-01-01

    A simple and convergent synthesis of 2,3-disubstituted indoles has been developed using a sequential Larock indole synthesis and silicon-based, cross-coupling reaction. Substituted 2-iodoanilines reacted with an alkynyldimethylsilyl tert-butyl ether to afford indole-2-silanols under the Larock heteroannulation conditions after hydrolysis. The corresponding sodium 2-indolylsilanolate salts successfully engaged in cross-coupling with aryl bromides and chlorides to afford multi-substituted indoles. The development of an alkynyldimethylsilyl tert-butyl ether as a masked silanol equivalent enabled a smooth heteroannulation process and the identification of a suitable catalyst/ligand combination provided for a facile cross-coupling reaction. PMID:19784400

  11. A new strategy for sequential assignment of intrinsically unstructured proteins based on 15N single isotope labelling

    NASA Astrophysics Data System (ADS)

    Lopez, Juan; Ahuja, Puneet; Gerard, Melanie; Wieruszeski, Jean-Michel; Lippens, Guy

    2013-11-01

    We describe a new efficient strategy for the sequential assignment of amide resonances of a conventional 15N-1H HSQC spectrum of intrinsically unfolded proteins, based on composite NOESY-TOCSY and TOCSY-NOESY mixing times. These composite mixing times lead to a Hα-proton mediated unidirectional transfer of amide to amide proton. We have implemented the composite mixing times in an HSQC-NOESY-HSQC manner to obtain directional connectivity between amides of neighbouring residues. We experimentally determine the optimal mixing times for both transfer schemes, and demonstrate its use in the assignment for both a fragment of the neuronal tau protein and for α-synuclein.

  12. Effects of sequentially released BMP-2 and BMP-7 from PELA microcapsule-based scaffolds on the bone regeneration

    PubMed Central

    Li, Xialin; Yi, Weihong; Jin, Anmin; Duan, Yang; Min, Shaoxiong

    2015-01-01

    Osteoinductive biomaterials are helpful for the therapy of large bone defects and provide an alternative to autogenous bone and allografts. Recently, multiple growth factors are delivered to mimic the natural process of bone healing in the bone tissue engineering. Herein, we investigated the effects of sequential released bone morphogenetic protein-2 (BMP-2) and bone morphogenetic protein-7 (BMP-7) from polylactide-poly (ethylene glycol)-polylactide (PELA) microcapsule-based scaffolds on the bone regeneration. Through improving the double emulsion/solvent evaporation technique, BMP-7 was encapsulated in PELA microcapsules, to the surface of which BMP-2 was attached. Then, the scaffold (BMP-2/PELA/BMP-7) was fused by these microcapsules with dichloromethane vapor method. In vitro, it sequentially delivered bioactive BMP-2 and BMP-7 and partially imitated the profile of BMPs expression during the fracture healing. To determine the bioactivity of released BMP-2 and BMP-7, alkaline phosphatase (AKP) activity was analyzed in MC3T3-E1 cells. When compared with simple BMP-2 plus BMP-7group and pure PELA group, the AKP activity in BMP-2/PELA/BMP-7 group significantly increased. MTT assay indicated the BMP-loaded PELA scaffold had no adverse effects on cell activity. In addition, the effects of BMP-loaded scaffolds were also investigated in a rat femoral defect model by micro-computed tomographic (mCT) and histological examination. At 4 and 8 weeks post-implantation, BMP-2/PELA/BMP-7 significantly promoted osteogenesis as compared to other groups. The scaffold underwent gradual degradation and replacement by new bones at 8 weeks. Our findings suggest that the sequential release of BMP-2 and BMP-7from PELA microcapsule-based scaffolds is promising for the therapy of bone defects. PMID:26396672

  13. Sequential quadratic programming-based fast path planning algorithm subject to no-fly zone constraints

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Ma, Shunjian; Sun, Mingwei; Yi, Haidong; Wang, Zenghui; Chen, Zengqiang

    2016-08-01

    Path planning plays an important role in aircraft guided systems. Multiple no-fly zones in the flight area make path planning a constrained nonlinear optimization problem. It is necessary to obtain a feasible optimal solution in real time. In this article, the flight path is specified to be composed of alternate line segments and circular arcs, in order to reformulate the problem into a static optimization one in terms of the waypoints. For the commonly used circular and polygonal no-fly zones, geometric conditions are established to determine whether or not the path intersects with them, and these can be readily programmed. Then, the original problem is transformed into a form that can be solved by the sequential quadratic programming method. The solution can be obtained quickly using the Sparse Nonlinear OPTimizer (SNOPT) package. Mathematical simulations are used to verify the effectiveness and rapidity of the proposed algorithm.

  14. Sequential Learning and Recognition of Comprehensive Behavioral Patterns Based on Flow of People

    NASA Astrophysics Data System (ADS)

    Gibo, Tatsuya; Aoki, Shigeki; Miyamoto, Takao; Iwata, Motoi; Shiozaki, Akira

    Recently, surveillance cameras have been set up everywhere, for example, in streets and public places, in order to detect irregular situations. In the existing surveillance systems, as only a handful of surveillance agents watch a large number of images acquired from surveillance cameras, there is a possibility that they may miss important scenes such as accidents or abnormal incidents. Therefore, we propose a method for sequential learning and the recognition of comprehensive behavioral patterns in crowded places. First, we comprehensively extract a flow of people from input images by using optical flow. Second, we extract behavioral patterns on the basis of change-point detection of the flow of people. Finally, in order to recognize an observed behavioral pattern, we draw a comparison between the behavioral pattern and previous behavioral patterns in the database. We verify the effectiveness of our approach by placing a surveillance camera on a campus.

  15. Sequential determination of trace 4-aminoazobenzene in multiple textiles based on nanoarrayed functionalized polystyrene substrate by surface enhanced Raman spectroscopy.

    PubMed

    Zhang, Zhuomin; Zhao, Cheng; Li, Gongke

    2016-07-01

    Achieving reproducible signals is a key point to improve the analytical precision and accuracy of surface enhanced Raman scattering (SERS) technique and further expand the application scope of SERS for on-site and rapid analysis of real sample with complex matrice. In this work, a novel Au@hydroxyl-functionalized polystyrene (Au@PS-OH) substrate was prepared by atom transfer radical polymerization and chemical assembly method, which possessed promised potential for the rapid and sequential analysis of multisamples coupling with SERS technique. Au@PS-OH substrate with regular nanoarrayed morphology possessed excellent anti-agglomeration capability even for testing solutions with strong basicity or acidity, mechanic and chemical stability due to the large amount of Au nanoparticles homogeneously and stably fixed on substrate surface. Moreover, excellent hydrophobicity of Au@PS-OH substrate could keep testing droplets of multiple samples stable and uniform spherical shape with similar contact angles to substrate, which guaranteed the reproducible SERS light paths and SERS signals during real sequential analysis. Then, an Au@PS-OH based SERS analytical method was developed and practically applied for the sequential determination of trace 4-aminoazobenzene in various textiles. It was satisfactory that the contents of trace 4-aminoazobenzene in black woolen, green woolen and yellow fiber cloth could be actually found and calculated to be 106.4, 120.9 and 140.8mg/kg with good recoveries of 76.0-118.9% and relative standard deviations of 1.6-5.1%. It is expected that this SERS method is suitable for on-site and rapid analysis of multiple samples in a short period. PMID:27154685

  16. Firefly Luciferase-Based Sequential Bioluminescence Resonance Energy Transfer (BRET)-Fluorescence Resonance Energy Transfer (FRET) Protease Assays.

    PubMed

    Branchini, Bruce

    2016-01-01

    We describe here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyzes yellow-green (560 nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-Infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41 nM for caspase 3, 1.0 nM for thrombin, and 58 nM for factor Xa were realized with a scanning fluorometer. This method successfully employs an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence to assay physiologically important protease activities and should be generally applicable to the measurement of any endoprotease lacking accessible cysteine residues. PMID:27424898

  17. Individually addressable electrode array for multianalyte electrochemiluminescent immunoassay based on a sequential triggering strategy.

    PubMed

    Wang, Lin; Wei, Wei; Han, Jing; Fu, Zhifeng

    2012-02-01

    Multianalyte immunoassay in a single run is often necessary to monitor or quantitate several components in a complex sample matrix for various purposes. In this paper we present a novel, individually addressable electrode array for sequential electrochemiluminescent (ECL) immunoassay using a non-array detector. An immunosensor array was fabricated by site-selectively immobilizing multiple antigens on different electrodes. With a competitive immunoassay format, the amounts of the bound Ru(bpy)(3)(2+) derivative labeled antibodies decreased with the increase of the antigens in the sample, and the ECL signals from different immunosensors were collected in turn by a photomultiplier with the aid of a home-made single-pore-three-throw switch. Using human IgG and rat IgG as model analytes, this multianalyte immunoassay showed detection limits down to 8.9 and 7.2 ng mL(-1) for them, respectively. The results for real sample analysis demonstrated that this strategy can provide a simple, sensitive, low-cost and high-throughput ECL immunosensor array for clinical diagnosis. PMID:22159267

  18. Design of LabVIEW®-based software for the control of sequential injection analysis instrumentation for the determination of morphine

    PubMed Central

    Lenehan, Claire E.; Lewis, Simon W.

    2002-01-01

    LabVIEW®-based software for the automation of a sequential injection analysis instrument for the determination of morphine is presented. Detection was based on its chemiluminescence reaction with acidic potassium permanganate in the presence of sodium polyphosphate. The calibration function approximated linearity (range 5 × 10-10 to 5 × 10-6 M) with a line of best fit of y=1.05x+8.9164 (R2 =0.9959), where y is the log10 signal (mV) and x is the log10 morphine concentration (M). Precision, as measured by relative standard deviation, was 0.7% for five replicate analyses of morphine standard (5 × 10-8 M). The limit of detection (3σ) was determined as 5 × 10-11 M morphine. PMID:18924729

  19. Cryptosystems based on chaotic dynamics

    SciTech Connect

    McNees, R.A.; Protopopescu, V.; Santoro, R.T.; Tolliver, J.S.

    1993-08-01

    An encryption scheme based on chaotic dynamics is presented. This scheme makes use of the efficient and reproducible generation of cryptographically secure pseudo random numbers from chaotic maps. The result is a system which encrypts quickly and possesses a large keyspace, even in small precision implementations. This system offers an excellent solution to several problems including the dissemination of key material, over the air rekeying, and other situations requiring the secure management of information.

  20. Modality-specific spectral dynamics in response to visual and tactile sequential shape information processing tasks: An MEG study using multivariate pattern classification analysis.

    PubMed

    Gohel, Bakul; Lee, Peter; Jeong, Yong

    2016-08-01

    Brain regions that respond to more than one sensory modality are characterized as multisensory regions. Studies on the processing of shape or object information have revealed recruitment of the lateral occipital cortex, posterior parietal cortex, and other regions regardless of input sensory modalities. However, it remains unknown whether such regions show similar (modality-invariant) or different (modality-specific) neural oscillatory dynamics, as recorded using magnetoencephalography (MEG), in response to identical shape information processing tasks delivered to different sensory modalities. Modality-invariant or modality-specific neural oscillatory dynamics indirectly suggest modality-independent or modality-dependent participation of particular brain regions, respectively. Therefore, this study investigated the modality-specificity of neural oscillatory dynamics in the form of spectral power modulation patterns in response to visual and tactile sequential shape-processing tasks that are well-matched in terms of speed and content between the sensory modalities. Task-related changes in spectral power modulation and differences in spectral power modulation between sensory modalities were investigated at source-space (voxel) level, using a multivariate pattern classification (MVPC) approach. Additionally, whole analyses were extended from the voxel level to the independent-component level to take account of signal leakage effects caused by inverse solution. The modality-specific spectral dynamics in multisensory and higher-order brain regions, such as the lateral occipital cortex, posterior parietal cortex, inferior temporal cortex, and other brain regions, showed task-related modulation in response to both sensory modalities. This suggests modality-dependency of such brain regions on the input sensory modality for sequential shape-information processing. PMID:27134037

  1. A new approach for improving flood model predictions based on the sequential assimilation of SAR-derived flood extent maps

    NASA Astrophysics Data System (ADS)

    Hostache, Renaud; Corato, Giovanni; Chini, Marco; Wood, Melissa; Giustarini, Laura; Matgen, Patrick

    2015-04-01

    Hydrodynamic models represent an important component in flood prediction systems. However, providing reliable model predictions and reducing the associated uncertainties remain challenging, especially in poorly gauged river basins. As Synthetic Aperture Radar-derived flood image databases are significant (and expected to grow rapidly with contributions from new satellites such as Sentinel-1) there are emerging opportunities for using these data collections to improve model predictions. In this context our aim is to contribute to the development of a global and near real-time remote sensing-based service that delivers flood predictions to support flood management. The study takes advantage of recently developed efficient, rapid and automatic algorithms for the delineation of flood extent using SAR images. The main objective of the study is to show how near real-time sequential assimilation of SAR derived flood extents can improve model predictions. As a test case we use the July 2007 flood event of the river Severn (UK) and the February 2007 flood event of the lower Zambezi (Mozambique). We use the Lisflood-FP hydraulic model and we adopt a particle filter-based assimilation scheme. An important issue in the framework of the assimilation of remote sensing-derived information is to quantify observation uncertainty. To do so we introduce for the first time an image processing approach that assigns to each pixel a 'probability to be flooded' based on its backscatter values. The sequential assimilation of SAR-derived flood extent maps shows a significant improvement in the hydraulic model predictions. The main achievement of the study is that model predictions are clearly improved by the assimilation of SAR-derived flood extent not only in terms of predicted flooded areas but also in terms of predicted discharge and water level surface elevation hydrographs.

  2. Substrate-independent sequential deposition process to obtain the lotus effect based on mussel-inspired polydopamine

    NASA Astrophysics Data System (ADS)

    Ou, Junfei; Pan, Bing; Chen, Yiwei; Xie, Chan; Xue, Mingshan; Wang, Fajun; Li, Wen

    2015-02-01

    A substrate-independent route to achieve the lotus effect on a variety of substrates is proposed based on mussel-inspired polydopamine (PDA), and was tested on titanium alloy, polypropylene and silicon substrates. The substrates were firstly coated with PDA and then sequentially transferred to aqueous CuCl2 and AgNO3 solutions for copper and silver deposition. Finally, the samples were passivated by the low-surface-energy molecules of 1-dodecanethiol, and surface superhydrophobicity (contact angle > 160°; sliding angle between 1° and 2°) could be obtained. Due to the strong adhesion of PDA to a wide range of materials, it is expected that this deposition process can be applied to a variety of other substrates including metal, polymer, and inorganic-nonmetallic materials.

  3. Personalized Recommendation of Learning Material Using Sequential Pattern Mining and Attribute Based Collaborative Filtering

    ERIC Educational Resources Information Center

    Salehi, Mojtaba; Nakhai Kamalabadi, Isa; Ghaznavi Ghoushchi, Mohammad Bagher

    2014-01-01

    Material recommender system is a significant part of e-learning systems for personalization and recommendation of appropriate materials to learners. However, in the existing recommendation algorithms, dynamic interests and multi-preference of learners and multidimensional-attribute of materials are not fully considered simultaneously. Moreover,…

  4. Mechanochemical solid-state synthesis of 2-aminothiazoles, quinoxalines and benzoylbenzofurans from ketones by one-pot sequential acid- and base-mediated reactions.

    PubMed

    Nagarajaiah, Honnappa; Mishra, Abhaya Kumar; Moorthy, Jarugu Narasimha

    2016-04-26

    α-Chloroketones - obtained by the atom-economical chlorination of ketones with trichloroisocyanuric acid (TCCA) in the presence of p-TSA under ball-milling conditions - were set up for a sequential base-mediated condensation reaction with thiourea/thiosemicarbazides, o-phenylenediamine and salicylaldehyde to afford 2-aminothiazoles, 2-hydrazinylthiazoles, quinoxalines and benzoylbenzofurans, respectively, in respectable yields. The viability of one-pot sequential acid- and base-mediated reactions in the solid state under ball-milling conditions is thus demonstrated. PMID:27072599

  5. Sequential RBF surrogate-based efficient optimization method for engineering design problems with expensive black-box functions

    NASA Astrophysics Data System (ADS)

    Peng, Lei; Liu, Li; Long, Teng; Guo, Xiaosong

    2014-11-01

    As a promising technique, surrogate-based design and optimization(SBDO) has been widely used in modern engineering design optimizations. Currently, static surrogate-based optimization methods have been successfully applied to expensive optimization problems. However, due to the low efficiency and poor flexibility, static surrogate-based optimization methods are difficult to efficiently solve practical engineering cases. At the aim of enhancing efficiency, a novel surrogate-based efficient optimization method is developed by using sequential radial basis function(SEO-SRBF). Moreover, augmented Lagrangian multiplier method is adopted to solve the problems involving expensive constraints. In order to study the performance of SEO-SRBF, several numerical benchmark functions and engineering problems are solved by SEO-SRBF and other well-known surrogate-based optimization methods including EGO, MPS, and IARSM. The optimal solutions, number of function evaluations, and algorithm execution time are recorded for comparison. The comparison results demonstrate that SEO-SRBF shows satisfactory performance in both optimization efficiency and global convergence capability. The CPU time required for running SEO-SRBF is dramatically less than that of other algorithms. In the torque arm optimization case using FEA simulation, SEO-SRBF further reduces 21% of the material volume compared with the solution from static-RBF subject to the stress constraint. This study provides the efficient strategy to solve expensive constrained optimization problems.

  6. Nonlinear dynamics based digital logic and circuits

    PubMed Central

    Kia, Behnam; Lindner, John. F.; Ditto, William L.

    2015-01-01

    We discuss the role and importance of dynamics in the brain and biological neural networks and argue that dynamics is one of the main missing elements in conventional Boolean logic and circuits. We summarize a simple dynamics based computing method, and categorize different techniques that we have introduced to realize logic, functionality, and programmability. We discuss the role and importance of coupled dynamics in networks of biological excitable cells, and then review our simple coupled dynamics based method for computing. In this paper, for the first time, we show how dynamics can be used and programmed to implement computation in any given base, including but not limited to base two. PMID:26029096

  7. Nonlinear dynamics based digital logic and circuits.

    PubMed

    Kia, Behnam; Lindner, John F; Ditto, William L

    2015-01-01

    We discuss the role and importance of dynamics in the brain and biological neural networks and argue that dynamics is one of the main missing elements in conventional Boolean logic and circuits. We summarize a simple dynamics based computing method, and categorize different techniques that we have introduced to realize logic, functionality, and programmability. We discuss the role and importance of coupled dynamics in networks of biological excitable cells, and then review our simple coupled dynamics based method for computing. In this paper, for the first time, we show how dynamics can be used and programmed to implement computation in any given base, including but not limited to base two. PMID:26029096

  8. A new approach for improving flood model predictions based on the sequential assimilation of SAR-derived flood extent maps

    NASA Astrophysics Data System (ADS)

    Hostache, R.; Corato, G.; Chini, M.; Wood, M.; Giustarini, L.; Matgen, P.

    2014-12-01

    Hydrodynamic models represent an important component in flood prediction systems. Unfortunately, providing reliable model predictions and reducing the associated uncertainties remain challenging; especially for poorly gauged river basins. As SAR flood image databases are significant (and expected to grow rapidly with contributions from new satellites such as Sentinel-1) there are obvious opportunities to use these flood images to improve model predictions. In this context our aim is to contribute to the development of a global and near real-time remote sensing service that delivers flood predictions to support flood management around the globe. The study takes advantage of recently developed efficient, rapid and automatic algorithms for the delineation of flood extent using SAR images. The main objective of the study is to show how near real-time sequential assimilation of SAR derived flood extents can improve model predictions. As a test case we use the July 2007 flood event of the river Severn (UK) and the February 2007 flood event of the lower river Zambezi (Mozambique). We use the Lisflood-FP hydraulic model and we adopt the particle filter as assimilation technique. An important issue in the framework of the assimilation of remote sensing-derived information is to quantify observation uncertainty. To do so we introduce an original image processing approach that assigns to each pixel a 'probability to be flooded' based on its backscatter values. The sequential assimilation of SAR-derived flood extent maps show a significant improvement in the hydraulic model predictions although the addition of sequences of images with similar flood extents has some limit. The main achievement of the study is that model predictions are clearly improved by the assimilation of SAR derived flood extent not only in terms of predicted flooded areas but also in terms of predicted discharge and water level hydrographs.

  9. Femtosecond molecular dynamics of tautomerization in model base pairs

    NASA Astrophysics Data System (ADS)

    Douhal, A.; Kim, S. K.; Zewail, A. H.

    1995-11-01

    HYDROGEN bonds commonly lend robustness and directionality to molecular recognition processes and supramolecular structures1,2. In particular, the two or three hydrogen bonds in Watson-Crick base pairs bind the double-stranded DNA helix and determine the complementarity of the pairing. Watson and Crick pointed out3, however, that the possible tautomers of base pairs, in which hydrogen atoms become attached to the donor atom of the hydrogen bond, might disturb the genetic code, as the tautomer is capable of pairing with different partners. But the dynamics of hydrogen bonds in general, and of this tautomerization process in particular, are not well understood. Here we report observations of the femtosecond dynamics of tautomerization in model base pairs (7-azaindole dimers) containing two hydrogen bonds. Because of the femtosecond resolution of proton motions, we are able to examine the cooperativity of formation of the tautomer (in which the protons on each base are shifted sequentially to the other base), and to determine the characteristic timescales of the motions in a solvent-free environment. We find that the first step occurs on a timescale of a few hundred femtoseconds, whereas the second step, to form the full tautomer, is much slower, taking place within several picoseconds; the timescales are changed significantly by replacing hydrogen with deuterium. These results establish the molecular basis of the dynamics and the role of quantum tunnelling.

  10. On the Use of Adaptive Instructional Images Based on the Sequential-Global Dimension of the Felder-Silverman Learning Style Theory

    ERIC Educational Resources Information Center

    Filippidis, Stavros K.; Tsoukalas, Ioannis A.

    2009-01-01

    An adaptive educational system that uses adaptive presentation is presented. In this system fragments of different images present the same content and the system can choose the one most relevant to the user based on the sequential-global dimension of Felder-Silverman's learning style theory. In order to retrieve the learning style of each student…

  11. Scheduling satellite-based SAR acquisition for sequential assimilation of water level observations into flood modelling

    NASA Astrophysics Data System (ADS)

    García-Pintado, Javier; Neal, Jeff C.; Mason, David C.; Dance, Sarah L.; Bates, Paul D.

    2013-07-01

    Satellite-based Synthetic Aperture Radar (SAR) has proved useful for obtaining information on flood extent, which, when intersected with a Digital Elevation Model (DEM) of the floodplain, provides water level observations that can be assimilated into a hydrodynamic model to decrease forecast uncertainty. With an increasing number of operational satellites with SAR capability, information on the relationship between satellite first visit and revisit time and forecast performance is required to optimise the operational scheduling of satellite imagery. By using an Ensemble Transform Kalman Filter (ETKF) and a synthetic analysis with the 2D hydrodynamic model LISFLOOD-FP based on a real flooding case affecting an urban area (summer 2007, Tewkesbury, Southwest UK), we evaluate the sensitivity of the forecast performance to visit parameters. We emulate a generic hydrologic-hydrodynamic modelling cascade by imposing a bias and spatiotemporal correlations to the inflow error ensemble into the hydrodynamic domain. First, in agreement with previous research, estimation and correction for this bias leads to a clear improvement in keeping the forecast on track. Second, imagery obtained early in the flood is shown to have a large influence on forecast statistics. Revisit interval is most influential for early observations. The results are promising for the future of remote sensing-based water level observations for real-time flood forecasting in complex scenarios.

  12. Dynamic holographic three-dimensional projection based on liquid crystal spatial light modulator and cylindrical fog screen

    NASA Astrophysics Data System (ADS)

    Zeng, Zhenxiang; Zheng, Huadong; Lu, Xiaoqian; Gao, Hongyue; Yu, Yingjie

    2015-10-01

    A dynamic holographic three-dimensional (3D) projection based on phase-only liquid crystal spatial light modulator (LC-SLM) and cylindrical fog 3D screen is introduced. Sequential kinoforms of a 3D real existing object are calculated from sixty viewing angles using the slice-based fresnel diffraction algorithm. To suppress speckle noise of reconstructed images, sub-kinoforms for each viewing angle are calculated by adding dynamic pseudorandom initial phase factor into each object plane. The sequential kinoforms are reconstructed by a holographic reconstruction system based on phase-only LC-SLM. A specially designed cylindrical fog 3D screen is used as the scattered carrying medium to project the dynamic 3D images. Through our holographic 3D projection system, a vivid dynamic holographic reconstructed projection image can be observed by some observers at the same time.

  13. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling.

    PubMed

    Aerts, Sam; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

    2013-10-01

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information-inside hotspots or in search of them-based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km2. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. PMID:23759207

  14. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling

    SciTech Connect

    Aerts, Sam Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

    2013-10-15

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information—inside hotspots or in search of them—based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km{sup 2}. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2 dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. -- Highlights: • We present an

  15. Sequential design of a novel PVA-based crosslinked ethylenic homopolymer for extended drug delivery.

    PubMed

    Pillay, Viness; Sibanda, Wilbert; Danckwerts, Michael P

    2005-09-14

    A Box-Behnken Design was employed to study the influence of boric acid, sodium sulfate, ammonia and n-propanol in the formulation of crosslinked ethylenic homopolymeric (CEH) gelispheres from native polyvinyl alcohol (PVA). The dependent variables studied included the size of the spherical gelispheres, drug encapsulation efficiency, in vitro dissolution after 30 min and textural parameters, namely fracture force and matrix rupture energy. Based on these responses, an optimized CEH gelisphere matrix was formulated and thereafter incorporated as a powder into a candidate crosslinked zinc-pectinate multiple-unit device to assess its effect on modifying drug release. In the case of the CEH-loaded zinc-pectinate gelispheres, it was determined via constrained optimization that a maximum drug encapsulation efficiency of 28.63% could be obtained under the conditions of 0% (w/v) CEH, 13 h of crosslinking and drying temperature of 60 degrees C. On the other hand, initial drug release could be significantly retarded when 0.10% (w/v) of CEH was included in the formulation and crosslinked for 24 h at 40 degrees C. In this regard, CEH induced a 4 h lag phase. Furthermore, zero-order drug release was produced and could be maintained over several weeks. Kinetic analysis of drug release further supported that CEH inhibits polymer relaxation (k2Based on these results, the CEH-zinc-pectinate drug delivery system appears to be a suitable carrier that may be employed for long-term administration for, e.g. via subcutaneous implantation. PMID:16023807

  16. Time-sequential autostereoscopic 3-D display with a novel directional backlight system based on volume-holographic optical elements.

    PubMed

    Hwang, Yong Seok; Bruder, Friedrich-Karl; Fäcke, Thomas; Kim, Seung-Cheol; Walze, Günther; Hagen, Rainer; Kim, Eun-Soo

    2014-04-21

    A novel directional backlight system based on volume-holographic optical elements (VHOEs) is demonstrated for time-sequential autostereoscopic three-dimensional (3-D) flat-panel displays. Here, VHOEs are employed to control the direction of light for a time-multiplexed display for each of the left and the right view. Those VHOEs are fabricated by recording interference patterns between collimated reference beams and diverging object beams for each of the left and right eyes on the volume holographic recording material. For this, self-developing photopolymer films (Bayfol® HX) were used, since those simplify the manufacturing process of VHOEs substantially. Here, the directional lights are similar to the collimated reference beams that were used to record the VHOEs and create two diffracted beams similar to the object beams used for recording the VHOEs. Then, those diffracted beams read the left and right images alternately shown on the LCD panel and form two converging viewing zones in front of the user's eyes. By this he can perceive the 3-D image. Theoretical predictions and experimental results are presented and the performance of the developed prototype is shown. PMID:24787867

  17. Sequential Monte Carlo filter for state estimation of LiFePO4 batteries based on an online updated model

    NASA Astrophysics Data System (ADS)

    Li, Jiahao; Klee Barillas, Joaquin; Guenther, Clemens; Danzer, Michael A.

    2014-02-01

    Battery state monitoring is one of the key techniques in battery management systems e.g. in electric vehicles. An accurate estimation can help to improve the system performance and to prolong the battery remaining useful life. Main challenges for the state estimation for LiFePO4 batteries are the flat characteristic of open-circuit-voltage over battery state of charge (SOC) and the existence of hysteresis phenomena. Classical estimation approaches like Kalman filtering show limitations to handle nonlinear and non-Gaussian error distribution problems. In addition, uncertainties in the battery model parameters must be taken into account to describe the battery degradation. In this paper, a novel model-based method combining a Sequential Monte Carlo filter with adaptive control to determine the cell SOC and its electric impedance is presented. The applicability of this dual estimator is verified using measurement data acquired from a commercial LiFePO4 cell. Due to a better handling of the hysteresis problem, results show the benefits of the proposed method against the estimation with an Extended Kalman filter.

  18. Sequential approximate optimization-based robust design of SiC-Si3N4 nanocomposite microstructures

    NASA Astrophysics Data System (ADS)

    Mejía-Rodríguez, Gilberto; Renaud, John E.; Kim, Han Sung; Tomar, Vikas

    2013-03-01

    A simulation-based robust design optimization methodology to predict the most suitable microstructures of SiC-Si 3N 4 nanocomposites for desired high-temperature toughness is presented. The focus is on finding robust nanocomposite microstructures with maximum toughness at two temperatures: 1500°C and 1600°C. Within this context a sequential approximate optimization algorithm under uncertainty is applied to six different test problems addressing different aspects of robust microstructure generation. During optimization, statistical uncertainties inherent to the computational microstructural generation are quantified and introduced in the optimization framework. The results show that the SiC volume fraction, the number of Si 3N 4 grains, the grain size distribution of the Si 3N 4 grains, and the grain size of the SiC particles have varied effects on the microstructure toughness at different temperatures. At 1500°C, the preferred microstructure is the one with higher Si 3N 4 volume fraction, whereas at 1600°C, the preferred microstructure is the one with higher SiC volume fraction.

  19. Deciding when to decide: time-variant sequential sampling models explain the emergence of value-based decisions in the human brain.

    PubMed

    Gluth, Sebastian; Rieskamp, Jörg; Büchel, Christian

    2012-08-01

    The cognitive and neuronal mechanisms of perceptual decision making have been successfully linked to sequential sampling models. These models describe the decision process as a gradual accumulation of sensory evidence over time. The temporal evolution of economic choices, however, remains largely unexplored. We tested whether sequential sampling models help to understand the formation of value-based decisions in terms of behavior and brain responses. We used functional magnetic resonance imaging (fMRI) to measure brain activity while human participants performed a buying task in which they freely decided upon how and when to choose. Behavior was accurately predicted by a time-variant sequential sampling model that uses a decreasing rather than fixed decision threshold to estimate the time point of the decision. Presupplementary motor area, caudate nucleus, and anterior insula activation was associated with the accumulation of evidence over time. Furthermore, at the beginning of the decision process the fMRI signal in these regions accounted for trial-by-trial deviations from behavioral model predictions: relatively high activation preceded relatively early responses. The updating of value information was correlated with signals in the ventromedial prefrontal cortex, left and right orbitofrontal cortex, and ventral striatum but also in the primary motor cortex well before the response itself. Our results support a view of value-based decisions as emerging from sequential sampling of evidence and suggest a close link between the accumulation process and activity in the motor system when people are free to respond at any time. PMID:22855817

  20. Multicell state estimation using variation based sequential Monte Carlo filter for automotive battery packs

    NASA Astrophysics Data System (ADS)

    Li, Jiahao; Klee Barillas, Joaquin; Guenther, Clemens; Danzer, Michael A.

    2015-03-01

    Accurate state monitoring is required for the high performance of battery management systems (BMS) in electric vehicles. By using model-based observation methods, state estimation of a single cell can be achieved with non-linear filtering algorithms e.g. Kalman filtering and Particle filtering. Considering the limited computational capability of a BMS and its real-time constraint, duplication of this approach to a multicell system is very time consuming and can hardly be implemented for a large number of cells in a battery pack. Several possible solutions have been reported in recent years. In this work, an extended two-step estimation approach is studied. At first, the mean value of the battery state of charge is determined in the form of a probability density function (PDF). Secondly, the intrinsic variations in cell SOC and resistance are identified simultaneously in an extended framework using a recursive least squares (RLS) algorithm. The on-board reliability and estimation accuracy of the proposed method is validated by experiment and simulation using an NMC/graphite battery module.

  1. A Silicon-Based, Sequential Coat-and-Etch Process to Fabricate Nearly Perfect Substrate Surfaces

    SciTech Connect

    Mirkarimi, P B; Spiller, E; Baker, S L; Stearns, D G; Robinson, J C; Olynick, D L; Salmassi, F; Liddle, J A; Liang, T; Stivers, A R

    2005-07-05

    For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to {approx} 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize {approx}70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of {approx} 70{sup o} from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize {approx}70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.

  2. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task

    PubMed Central

    Laubacher, Marco; Aksöz, Efe A.; Binder-Macleod, Stuart; Hunt, Kenneth J.

    2016-01-01

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable. PMID:27478563

  3. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task.

    PubMed

    Laubacher, Marco; Aksöz, Efe A; Binder-Macleod, Stuart; Hunt, Kenneth J

    2016-06-13

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable. PMID:27478563

  4. Novel sequential process for enhanced dye synergistic degradation based on nano zero-valent iron and potassium permanganate.

    PubMed

    Wang, Xiangyu; Liu, Peng; Fu, Minglai; Ma, Jun; Ning, Ping

    2016-07-01

    A novel synergistic technology based on nano zero-valent iron (NZVI) and potassium permanganate (KMnO4) was developed for treatment of dye wastewater. The synergistic technology was significantly superior, where above 99% of methylene blue (MB) was removed, comparatively, removal efficiencies of MB with the sole technology of NZVI and KMnO4 at pH 6.39 being 52.9% and 63.1%, respectively. The advantages of this technology include (1) the in situ formed materials (manganese (hydr)oxides, iron hydroxides and MnFe oxide), resulting in the stable and high removal efficiency of MB and (2) high removal capacity in a wide range of pH value. Compared with simultaneous addition system of NZVI and KMnO4, MB removal was remarkably improved by sequential addition system, especially when KMnO4 addition time was optimized at 20 min. Analyses of crystal structure (XRD), morphological difference (FE-SEM), element valence and chemical groups (XPS) of NZVI before and after reaction had confirmed the formation of in situ materials, which obviously enhanced removal of MB by oxidation and adsorption. More importantly, the roles of in situ formed materials and degradation mechanism were innovatively investigated, and the results suggested that NCH3 bond of MB molecule was attacked by oxidants (KMnO4 and in situ manganese (hydr)oxides) at position C1 and C9, resulting in cleavage of chromophore. This study provides new insights about an applicable technology for treatment of dye wastewater. PMID:27105151

  5. Studying dynamic chaos in microwave ring generators based on normally magnetized ferromagnetic film

    NASA Astrophysics Data System (ADS)

    Kondrashov, A. V.; Ustinov, A. B.; Kalinikos, B. A.

    2016-02-01

    We present results of an experimental investigation of the transition to a microwave dynamic chaos regime in ring oscillators based on normally magnetized yttrium iron garnet (YIG) films. It is established that an increase in the ring gain leads to the sequential generation of monochromatic, periodic, quasi-periodic, and chaotic signals. The quasi-periodic regime is characterized by the appearance of secondary modulation of the signal amplitude. In the regime of dynamic chaos generation, the parameters can be controlled by gain of the ring.

  6. Asymmetric azidation-cycloaddition with open-chain peptide-based catalysts. A sequential enantioselective route to triazoles.

    PubMed

    Guerin, David J; Miller, Scott J

    2002-03-13

    A family of beta-substituted histidine-containing peptides has been synthesized to probe the effect of noncovalent conformational rigidification on catalyst enantioselectivity. Unambiguous enhancement of enantioselectivity in the conjugate addition of azide to alpha,beta-unsaturated carboxylate derivatives has been achieved, enabling application to a sequential asymmetric azidation/cycloaddition for the synthesis of optically enriched triazoles and triazolines. PMID:11878965

  7. Conformation-sensitive antibody-based point-of-care immunosensor for serum Ca(2+) using two-dimensional sequential binding reactions.

    PubMed

    Park, Ji-Na; Paek, Sung-Ho; Kim, Dong-Hyung; Seo, Sung-Min; Lim, Guei-Sam; Kang, Ju-Hee; Paek, Sung-Pil; Cho, Il-Hoon; Paek, Se-Hwan

    2016-11-15

    To assess the homeostasis of Ca(2+) metabolism, we have developed a rapid immunosensor for ionic calcium using a membrane chromatographic technique. As calcium-binding protein (CBP) is available for the recognition and undergone conformation change upon Ca(2+) binding, a monoclonal antibody sensitive to the altered structure of CBP has been employed. The sequential binding scheme was mathematically simulated and shown to match with the experimental results. At the initial stage, the rapid analytical system using lateral flow was constructed by immobilizing the antibody on the immuno-strip nitrocellulose membrane and labeling CBP with colloidal gold as a tracer. A major problem with this system in measuring ionic calcium levels was retarded migration of the gold tracer along the immuno-strip. It was conceivable that the divalent cation at a high concentration caused a change in the physical properties of the tracer, resulting in a non-specific interaction with the membrane surface. This problem was circumvented by first eluting a sample containing biotinylated CBP along the immuno-strip and then supplying the gold coupled to streptavidin across the signal generation pad of the strip. The color signal was then generated via biotin-SA linkage and measured using a smartphone-based detector developed in our laboratory. This two-dimensional chromatographic format completed the Ca(2+) analysis within 15min, the analytical performance covered the clinical dynamic range (0.25-2.5mM) and highly correlated with that of the reference system, i-STAT. These results inspired us to eventually investigate a dual-immunoassay system that measures simultaneously ionic calcium and parathyroid hormone, which regulates the ionic calcium level in serum. This will significantly simplify the current diagnostic protocols, which involve separate devices. PMID:27236727

  8. MRNet-based Dynamic Probe Class Library

    Energy Science and Technology Software Center (ESTSC)

    2006-12-19

    The Dynamic Probe Class Library (DPCL) is an API that allows for the modification of running code, or dynamic instrumentation. Dynamic instruction is an attractive technique for implementing performance analysis tools, debugging, or process steering because this method doesn't require the modification of the application's source code and hence avoids recompiling, re-linking, and restarting the application. The DPCL API is machine independent; hence DPCL-based tools built on one platform will work on another platform

  9. Sequential selection of economic good and action in medial frontal cortex of macaques during value-based decisions.

    PubMed

    Chen, Xiaomo; Stuphorn, Veit

    2015-01-01

    Value-based decisions could rely either on the selection of desired economic goods or on the selection of the actions that will obtain the goods. We investigated this question by recording from the supplementary eye field (SEF) of monkeys during a gambling task that allowed us to distinguish chosen good from chosen action signals. Analysis of the individual neuron activity, as well as of the population state-space dynamic, showed that SEF encodes first the chosen gamble option (the desired economic good) and only ~100 ms later the saccade that will obtain it (the chosen action). The action selection is likely driven by inhibitory interactions between different SEF neurons. Our results suggest that during value-based decisions, the selection of economic goods precedes and guides the selection of actions. The two selection steps serve different functions and can therefore not compensate for each other, even when information guiding both processes is given simultaneously. PMID:26613409

  10. A cross-sectional study to compare intraocular pressure measurement by sequential use of Goldman applanation tonometry, dynamic contour tonometry, ocular response analyzer, and Corvis ST

    PubMed Central

    Tejwani, Sushma; Dinakaran, Shoruba; Joshi, Anuja; Shetty, Rohit; Roy, Abhijit Sinha

    2015-01-01

    Objective: To study the correlation and effect of sequential measurement of intraocular pressure (IOP) with Goldmann applanation tonometer (GAT), ocular response analyzer (ORA), dynamic contour tonometer (DCT), and Corvis ST. Setting and Design: Observational cross-sectional series from the comprehensive clinic of a tertiary eye care center seen during December 2012. Methods: One hundred and twenty-five study eyes of 125 patients with normal IOP and biomechanical properties underwent IOP measurement on GAT, DCT, ORA, and Corvis ST; in four different sequences. Patients with high refractive errors, recent surgeries, glaucoma, and corneal disorders were excluded so as to rule out patients with evident altered corneal biomechanics. Statistical Analysis: Linear regression and Bland–Altman using MedCalc software. Results: Multivariate analysis of variance with repeated measures showed no influence of sequence of device use on IOP (P = 0.85). Linear regression r2 between GAT and Corvis ST, Corvis ST and Goldmann-correlated IOP (IOPg), and DCT and Corvis ST were 0.37 (P = 0.675), 0.63 (P = 0.607), and 0.19 (P = 0.708), respectively. The Bland–Altman agreement of Corvis ST with GAT, corneal compensated IOP, and IOPg was 2 mmHg (−5.0 to + 10.3), −0.5 mmHg (−8.1 to 7.1), and 0.5 mmHg (−6.2 to 7.1), respectively. Intraclass correlation coefficient for repeatability ranged from 0.81 to 0.96. Conclusions: Correlation between Corvis ST and ORA was found to be good and not so with GAT. However, agreement between the devices was statistically insignificant, and no influence of sequence was observed. PMID:26669331

  11. Accelerating PS model-based dynamic cardiac MRI using compressed sensing.

    PubMed

    Zhang, Xiaoyong; Xie, Guoxi; Shi, Caiyun; Su, Shi; Zhang, Yongqin; Liu, Xin; Qiu, Bensheng

    2016-02-01

    High spatiotemporal resolution MRI is a challenging topic in dynamic MRI field. Partial separability (PS) model has been successfully applied to dynamic cardiac MRI by exploiting data redundancy. However, the model requires substantial preprocessing data to accurately estimate the model parameters before image reconstruction. Since compressed sensing (CS) is a potential technique to accelerate MRI by reducing the number of acquired data, the combination of PS and CS, named as Stepped-SparsePS, was introduced to accelerate the preprocessing data acquisition of PS in this work. The proposed Stepped-SparsePS method sequentially reconstructs a set of aliased dynamic images in each channel based on PS model and then the final dynamic images from the aliased images using CS. The results from numerical simulations and in vivo experiments demonstrate that Stepped-SparsePS could significantly reduce data acquisition time while preserving high spatiotemporal resolution. PMID:26552006

  12. Sequential extractions for the study of radiocesium and radiostrontium dynamics in mineral and organic soils from Western Europe and Chernobyl areas

    SciTech Connect

    Rigol, A.; Roig, M.; Vidal, M.; Rauret, G.

    1999-03-15

    To study radiostrontium (RSr) and radiocesium (RCs) aging in soils, three sequential extraction schemes were used on Mediterranean loamy and loam-sandy soils, podsols and peaty podsols from the area near Chernobyl, and peats from Western Europe. Aging was quantified by changes in radionuclide distribution. Two factors were thought to affect radionuclide distribution: time elapsed since contamination and drying-wetting cycles. Changes in radionuclide distribution were of low significance in Mediterranean loamy and loam-sandy soils in the short term, even after drying-wetting cycles. In the short term, podsols and peaty podsols showed a decrease in the RSr exchangeable fraction in the laboratory samples, whereas samples taken 6 years after contamination did not show any further decrease. For RCs in podsols and peaty-podsols, the application of drying-wetting cycles for 9 months led to observe a 2--3-fold decrease in the exchangeable fraction, whereas time alone did not lead to any change. No RCs aging was observed in peats with a low or almost negligible content of mineral matter, low base saturation and low interception potential for RCs, even after drying-wetting cycles. Finally, changes in the radionuclide exchangeable fraction over time in these soils corresponded to changes in transfer factors over a similar period.

  13. Effects of a Web-Based Tailored Multiple-Lifestyle Intervention for Adults: A Two-Year Randomized Controlled Trial Comparing Sequential and Simultaneous Delivery Modes

    PubMed Central

    Kremers, Stef PJ; Vandelanotte, Corneel; van Adrichem, Mathieu JG; Schneider, Francine; Candel, Math JJM; de Vries, Hein

    2014-01-01

    Background Web-based computer-tailored interventions for multiple health behaviors can have a significant public health impact. Yet, few randomized controlled trials have tested this assumption. Objective The objective of this paper was to test the effects of a sequential and simultaneous Web-based tailored intervention on multiple lifestyle behaviors. Methods A randomized controlled trial was conducted with 3 tailoring conditions (ie, sequential, simultaneous, and control conditions) in the Netherlands in 2009-2012. Follow-up measurements took place after 12 and 24 months. The intervention content was based on the I-Change model. In a health risk appraisal, all respondents (N=5055) received feedback on their lifestyle behaviors that indicated whether they complied with the Dutch guidelines for physical activity, vegetable consumption, fruit consumption, alcohol intake, and smoking. Participants in the sequential (n=1736) and simultaneous (n=1638) conditions received tailored motivational feedback to change unhealthy behaviors one at a time (sequential) or all at the same time (simultaneous). Mixed model analyses were performed as primary analyses; regression analyses were done as sensitivity analyses. An overall risk score was used as outcome measure, then effects on the 5 individual lifestyle behaviors were assessed and a process evaluation was performed regarding exposure to and appreciation of the intervention. Results Both tailoring strategies were associated with small self-reported behavioral changes. The sequential condition had the most significant effects compared to the control condition after 12 months (T1, effect size=0.28). After 24 months (T2), the simultaneous condition was most effective (effect size=0.18). All 5 individual lifestyle behaviors changed over time, but few effects differed significantly between the conditions. At both follow-ups, the sequential condition had significant changes in smoking abstinence compared to the simultaneous

  14. Map-based models in neuronal dynamics

    NASA Astrophysics Data System (ADS)

    Ibarz, B.; Casado, J. M.; Sanjuán, M. A. F.

    2011-04-01

    Ever since the pioneering work of Hodgkin and Huxley, biological neuron models have consisted of ODEs representing the evolution of the transmembrane voltage and the dynamics of ionic conductances. It is only recently that discrete dynamical systems-also known as maps-have begun to receive attention as valid phenomenological neuron models. The present review tries to provide a coherent perspective of map-based biological neuron models, describing their dynamical properties; stressing the similarities and differences, both among them and in relation to continuous-time models; exploring their behavior in networks; and examining their wide-ranging possibilities of application in computational neuroscience.

  15. Evolutionary history of the endangered fish Zoogoneticus quitzeoensis (Bean, 1898) (Cyprinodontiformes: Goodeidae) using a sequential approach to phylogeography based on mitochondrial and nuclear DNA data

    PubMed Central

    2008-01-01

    Background Tectonic, volcanic and climatic events that produce changes in hydrographic systems are the main causes of diversification and speciation of freshwater fishes. Elucidate the evolutionary history of freshwater fishes permits to infer theories on the biotic and geological evolution of a region, which can further be applied to understand processes of population divergence, speciation and for conservation purposes. The freshwater ecosystems in Central Mexico are characterized by their genesis dynamism, destruction, and compartmentalization induced by intense geologic activity and climatic changes since the early Miocene. The endangered goodeid Zoogoneticus quitzeoensis is widely distributed across Central México, thus making it a good model for phylogeographic analyses in this area. Results We addressed the phylogeography, evolutionary history and genetic structure of populations of Z. quitzeoensis through a sequential approach, based on both microsatellite and mitochondrial cytochrome b sequences. Most haplotypes were private to particular locations. All the populations analysed showed a remarkable number of haplotypes. The level of gene diversity within populations was H¯d = 0.987 (0.714 – 1.00). However, in general the nucleotide diversity was low, π = 0.0173 (0.0015 – 0.0049). Significant genetic structure was found among populations at the mitochondrial and nuclear level (ΦST = 0.836 and FST = 0.262, respectively). We distinguished two well-defined mitochondrial lineages that were separated ca. 3.3 million years ago (Mya). The time since expansion was ca. 1.5 × 106 years ago for Lineage I and ca. 860,000 years ago for Lineage II. Also, genetic patterns of differentiation, between and within lineages, are described at different historical timescales. Conclusion Our mtDNA data indicates that the evolution of the different genetic groups is more related to ancient geological and climatic events (Middle Pliocene, ca. 3.3 Mya) than to the current

  16. Fluorescence 'on-off-on' chemosensor for sequential recognition of Fe(3+) and Hg(2+) in water based on tetraphenylethylene motif.

    PubMed

    Yan, Yuanyuan; Che, Zhiping; Yu, Xiang; Zhi, Xiaoyan; Wang, Juanjuan; Xu, Hui

    2013-01-15

    A novel selective and sensitive fluorescence 'on-off-on' probe based on tetraphenylethylene (TPE) motif for sequential recognition of Fe(3+) and Hg(2+) in water has been developed. Especially the complex 6-Fe(3+) could behave as a 'turn on' fluorescent sensor over a wide-range pH value for detection of Hg(2+). The selectivity of this complex for Hg(2+) over other heavy and transition metal ions is excellent, and its sensitivity for Hg(2+) is at 2 ppb in water. PMID:23218869

  17. Immunoreceptor tyrosine-based inhibitory motif (ITIM)-mediated inhibitory signaling is regulated by sequential phosphorylation mediated by distinct nonreceptor tyrosine kinases: a case study involving PECAM-1.

    PubMed

    Tourdot, Benjamin E; Brenner, Michelle K; Keough, Kathleen C; Holyst, Trudy; Newman, Peter J; Newman, Debra K

    2013-04-16

    The activation state of many blood and vascular cells is tightly controlled by a delicate balance between receptors that contain immunoreceptor tyrosine-based activation motifs (ITAMs) and those that contain immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Precisely how the timing of cellular activation by ITAM-coupled receptors is regulated by ITIM-containing receptors is, however, poorly understood. Using platelet endothelial cell adhesion molecule 1 (PECAM-1) as a prototypical ITIM-bearing receptor, we demonstrate that initiation of inhibitory signaling occurs via a novel, sequential process in which Src family kinases phosphorylate the C-terminal ITIM, thereby enabling phosphorylation of the N-terminal ITIM of PECAM-1 by other Src homology 2 domain-containing nonreceptor tyrosine kinases (NRTKs). NRTKs capable of mediating the second phosphorylation event include C-terminal Src kinase (Csk) and Bruton's tyrosine kinase (Btk). Btk and Csk function downstream of phosphatidylinositol 3-kinase (PI3K) activation during ITAM-dependent platelet activation. In ITAM-activated platelets that were treated with a PI3K inhibitor, PECAM-1 was phosphorylated but did not bind the tandem SH2 domain-containing tyrosine phosphatase SHP-2, indicating that it was not phosphorylated on its N-terminal ITIM. Csk bound to and phosphorylated PECAM-1 more efficiently than did Btk and required its SH2 domain to perform these functions. Additionally, the phosphorylation of the N-terminal ITIM of Siglec-9 by Csk is enhanced by the prior phosphorylation of its C-terminal ITIM, providing evidence that the ITIMs of other dual ITIM-containing receptors are also sequentially phosphorylated. On the basis of these findings, we propose that sequential ITIM phosphorylation provides a general mechanism for precise temporal control over the recruitment and activation of tandem SH2 domain-containing tyrosine phosphatases that dampen ITAM-dependent signals. PMID:23418871

  18. Grouped frequent sequential patterns derived from terrestrial image time series to monitor landslide behaviour - Application to the dynamics of the Sanières/Roche Plombée rockslide.

    NASA Astrophysics Data System (ADS)

    Péricault, Youen; Pothier, Catherine; Méger, Nicolas; Trouvé, Emmanuel; Vernier, Flavien; Rigotti, Christophe; Malet, Jean-Philippe

    2016-04-01

    Image time series acquired with remote sensing methods based on optical terrestrial photogrammetry have great potential for understanding and monitoring the Earth surface dynamics at local scale, and are particularly interesting for landslide monitoring. Image correlation techniques can be applied to calculate the displacement fields, in either the image geometry or the terrain geometry if orthorectification procedures are applied. The resulting products are times series of displacement vectors for each epoch in which knowledge extraction techniques can be applied to discover relevant movement patterns in space and time. We used an unsupervised method (Grouped Frequent Sequential patterns / GFS-patterns) based on the mining of the displacement field. The method was originally developed for the analysis of time series of satellite images. It involves the extraction of trends / sub-trends affecting each pixel covering at least a minimum surface area and sufficiently connected to each other. The results of the mining are presented in spatio-temporal location maps (STL-map) of each GFS-pattern. In these maps, the spatial information is given by the pixel locations and the time information is displayed using a color ramp. The method is tested on a time series of 36 optical terrestrial images of the Sanières/Roche Plombée rockslide (South East French Alps) from 28 of July to 1 September 2014. From this series 35 2D displacement fields were calculated for epochs of three days, and the time series of vector magnitude and direction were analysed with GFS-patterns / STL-map. The method allowed identifying several patterns corresponding to different kinematical behaviour of the rockslide (long-term creep at the top of the slope, surficial movement of the debris at the base of the slope). The unsupervised knowledge extraction method GFS-pattern / STL-map, originally developed to analyse time series of satellite images showed in this study real possibilities of use for

  19. Sequential selection of economic good and action in medial frontal cortex of macaques during value-based decisions

    PubMed Central

    Chen, Xiaomo; Stuphorn, Veit

    2015-01-01

    Value-based decisions could rely either on the selection of desired economic goods or on the selection of the actions that will obtain the goods. We investigated this question by recording from the supplementary eye field (SEF) of monkeys during a gambling task that allowed us to distinguish chosen good from chosen action signals. Analysis of the individual neuron activity, as well as of the population state-space dynamic, showed that SEF encodes first the chosen gamble option (the desired economic good) and only ~100 ms later the saccade that will obtain it (the chosen action). The action selection is likely driven by inhibitory interactions between different SEF neurons. Our results suggest that during value-based decisions, the selection of economic goods precedes and guides the selection of actions. The two selection steps serve different functions and can therefore not compensate for each other, even when information guiding both processes is given simultaneously. DOI: http://dx.doi.org/10.7554/eLife.09418.001 PMID:26613409

  20. Fluorescence spectra shape based dynamic thermometry

    NASA Astrophysics Data System (ADS)

    Liu, Liwang; Creten, Sebastiaan; Firdaus, Yuliar; Agustin Flores Cuautle, Jose Jesus; Kouyaté, Mansour; Van der Auweraer, Mark; Glorieux, Christ

    2014-01-01

    An entirely optical, dynamic thermometry technique based on the temperature dependence of a fluorescence spectrum is presented. Different from conventional intensity-based fluorescence thermometry, in this work, neural network recognition is employed to extract the sample temperature from the magnitude and shape of recorded fluorescence spectra. As a demonstration to determine the depth profile of dynamical temperature variations and of the thermal and optical properties of semitransparent samples, in-depth photothermally induced periodical temperature oscillations of a rhodamine B and copper chloride dyed glycerol sample were measured with an accuracy of 4.2 mK.Hz-1/2 and fitted well by a 1D thermal diffusion model.

  1. Sequential effects: Superstition or rational behavior?

    PubMed Central

    Yu, Angela J.; Cohen, Jonathan D.

    2012-01-01

    In a variety of behavioral tasks, subjects exhibit an automatic and apparently suboptimal sequential effect: they respond more rapidly and accurately to a stimulus if it reinforces a local pattern in stimulus history, such as a string of repetitions or alternations, compared to when it violates such a pattern. This is often the case even if the local trends arise by chance in the context of a randomized design, such that stimulus history has no real predictive power. In this work, we use a normative Bayesian framework to examine the hypothesis that such idiosyncrasies may reflect the inadvertent engagement of mechanisms critical for adapting to a changing environment. We show that prior belief in non-stationarity can induce experimentally observed sequential effects in an otherwise Bayes-optimal algorithm. The Bayesian algorithm is shown to be well approximated by linear-exponential filtering of past observations, a feature also apparent in the behavioral data. We derive an explicit relationship between the parameters and computations of the exact Bayesian algorithm and those of the approximate linear-exponential filter. Since the latter is equivalent to a leaky-integration process, a commonly used model of neuronal dynamics underlying perceptual decision-making and trial-to-trial dependencies, our model provides a principled account of why such dynamics are useful. We also show that parameter-tuning of the leaky-integration process is possible, using stochastic gradient descent based only on the noisy binary inputs. This is a proof of concept that not only can neurons implement near-optimal prediction based on standard neuronal dynamics, but that they can also learn to tune the processing parameters without explicitly representing probabilities. PMID:26412953

  2. Inference for the median residual life function in sequential multiple assignment randomized trials

    PubMed Central

    Kidwell, Kelley M.; Ko, Jin H.; Wahed, Abdus S.

    2014-01-01

    In survival analysis, median residual lifetime is often used as a summary measure to assess treatment effectiveness; it is not clear, however, how such a quantity could be estimated for a given dynamic treatment regimen using data from sequential randomized clinical trials. We propose a method to estimate a dynamic treatment regimen-specific median residual life (MERL) function from sequential multiple assignment randomized trials. We present the MERL estimator, which is based on inverse probability weighting, as well as, two variance estimates for the MERL estimator. One variance estimate follows from Lunceford, Davidian and Tsiatis’ 2002 survival function-based variance estimate and the other uses the sandwich estimator. The MERL estimator is evaluated, and its two variance estimates are compared through simulation studies, showing that the estimator and both variance estimates produce approximately unbiased results in large samples. To demonstrate our methods, the estimator has been applied to data from a sequentially randomized leukemia clinical trial. PMID:24254496

  3. Sequential visibility-graph motifs

    NASA Astrophysics Data System (ADS)

    Iacovacci, Jacopo; Lacasa, Lucas

    2016-04-01

    Visibility algorithms transform time series into graphs and encode dynamical information in their topology, paving the way for graph-theoretical time series analysis as well as building a bridge between nonlinear dynamics and network science. In this work we introduce and study the concept of sequential visibility-graph motifs, smaller substructures of n consecutive nodes that appear with characteristic frequencies. We develop a theory to compute in an exact way the motif profiles associated with general classes of deterministic and stochastic dynamics. We find that this simple property is indeed a highly informative and computationally efficient feature capable of distinguishing among different dynamics and robust against noise contamination. We finally confirm that it can be used in practice to perform unsupervised learning, by extracting motif profiles from experimental heart-rate series and being able, accordingly, to disentangle meditative from other relaxation states. Applications of this general theory include the automatic classification and description of physical, biological, and financial time series.

  4. Haptics-based dynamic implicit solid modeling.

    PubMed

    Hua, Jing; Qin, Hong

    2004-01-01

    This paper systematically presents a novel, interactive solid modeling framework, Haptics-based Dynamic Implicit Solid Modeling, which is founded upon volumetric implicit functions and powerful physics-based modeling. In particular, we augment our modeling framework with a haptic mechanism in order to take advantage of additional realism associated with a 3D haptic interface. Our dynamic implicit solids are semi-algebraic sets of volumetric implicit functions and are governed by the principles of dynamics, hence responding to sculpting forces in a natural and predictable manner. In order to directly manipulate existing volumetric data sets as well as point clouds, we develop a hierarchical fitting algorithm to reconstruct and represent discrete data sets using our continuous implicit functions, which permit users to further design and edit those existing 3D models in real-time using a large variety of haptic and geometric toolkits, and visualize their interactive deformation at arbitrary resolution. The additional geometric and physical constraints afford more sophisticated control of the dynamic implicit solids. The versatility of our dynamic implicit modeling enables the user to easily modify both the geometry and the topology of modeled objects, while the inherent physical properties can offer an intuitive haptic interface for direct manipulation with force feedback. PMID:15794139

  5. Numerical simulation of the spreading dynamic responses of the multibody system with a floating base

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaobing; Shao, Luzhong; Shao, Fei

    2015-07-01

    To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a four-body system with a floating base and the motions are analyzed when the upper parts are spread sequentially or synchronously. The rolling, swaying and heaving temporal variations are obtained when the multibody system is under the conditions of the static water along with the wave loads and the mean wind loads or the single pulse wind loads, respectively. The moment variations of each joint under the single pulse wind load are also gained. The numerical results showed that the swaying of the floating base is almost not influenced by the spreading time or form when the upper parts spread sequentially or synchronously, while the rolling and the heaving mainly depend on the spreading time and forms. The swaying and heaving motions are influenced significantly by the mean wind loads. The single pulse wind load also has influences on the dynamic responses. The torque of joint 3 and joint 4 in the single pulse wind environment may be twice that in the windless environment when the system spreads with 60 s duration.

  6. Monitoring variations of dimethyl sulfide and dimethylsulfoniopropionate in seawater and the atmosphere based on sequential vapor generation and ion molecule reaction mass spectrometry.

    PubMed

    Iyadomi, Satoshi; Ezoe, Kentaro; Ohira, Shin-Ichi; Toda, Kei

    2016-04-20

    To monitor the fluctuations of dimethyl sulfur compounds at the seawater/atmosphere interface, an automated system was developed based on sequential injection analysis coupled with vapor generation-ion molecule reaction mass spectrometry (SIA-VG-IMRMS). Using this analytical system, dissolved dimethyl sulfide (DMSaq) and dimethylsulfoniopropionate (DMSP), a precursor to DMS in seawater, were monitored together sequentially with atmospheric dimethyl sulfide (DMSg). A shift from the equilibrium point between DMSaq and DMSg results in the emission of DMS to the atmosphere. Atmospheric DMS emitted from seawater plays an important role as a source of cloud condensation nuclei, which influences the oceanic climate. Water samples were taken periodically and dissolved DMSaq was vaporized for analysis by IMRMS. After that, DMSP was hydrolyzed to DMS and acrylic acid, and analyzed in the same manner as DMSaq. The vaporization behavior and hydrolysis of DMSP to DMS were investigated to optimize these conditions. Frequent (every 30 min) determination of the three components, DMSaq/DMSP (nanomolar) and DMSg (ppbv), was carried out by SIA-VG-IMRMS. Field analysis of the dimethyl sulfur compounds was undertaken at a coastal station, which succeeded in showing detailed variations of the compounds in a natural setting. Observed concentrations of the dimethyl sulfur compounds both in the atmosphere and seawater largely changed with time and similar variations were repeatedly observed over several days, suggesting diurnal variations in the DMS flux at the seawater/atmosphere interface. PMID:27046734

  7. Sequential fragmentation/transport theory, pyroclast size-density relationships, and the emplacement dynamics of pyroclastic density currents — A case study on the Mt. St. Helens (USA) 1980 eruption

    NASA Astrophysics Data System (ADS)

    Mackaman-Lofland, Chelsea; Brand, Brittany D.; Taddeucci, Jacopo; Wohletz, Kenneth

    2014-04-01

    Pyroclastic density currents (PDCs) are the most dangerous hazard associated with explosive volcanic eruptions. Despite recent advancements in the general understanding of PDC dynamics, limited direct observation and/or outcrop scarcity often hinder the interpretation of specific transport and depositional processes at many volcanoes. This study explores the potential of sequential fragmentation/transport theory (SFT; cf. Wohletz et al., 1989), a modeling method capable of predicting particle mass distributions based on the physical principles of fragmentation and transport, to retrieve the transport and depositional dynamics of well-characterized PDCs from the size and density distributions of individual components within the deposits. The extensive vertical and lateral exposures through the May 18th, 1980 PDC deposits at Mt. St. Helens (MSH) provide constraints on PDC regimes and flow boundary conditions at specific locations across the depositional area. Application to MSH deposits suggests that SFT parameter distributions can be effectively used to characterize flow boundary conditions and emplacement processes for a variety of PDC lithofacies and deposit locations. Results demonstrate that (1) the SFT approach reflects particle fragmentation and transport mechanisms regardless of variations in initial component distributions, consistent with results from previous studies; (2) SFT analysis reveals changes in particle characteristics that are not directly observable in grain size and fabric data; and (3) SFT parameters are more sensitive to regional transport conditions than local (outcrop-scale) depositional processes. The particle processing trends produced using SFT analysis are consistent with the degree of particle processing inferred from lithofacies architectures: for all lithofacies examined in this study, suspension sedimentation products exhibit much better processing than concentrated current deposits. Integrated field observations and SFT results

  8. Sequential injection analysis of lead using time-based colorimetric detection and preconcentration on an anionic-exchange resin.

    PubMed

    Aracama, Nestor Zárate; Araújo, Alberto N; Perez-Olmos, Ricardo

    2004-04-01

    The development of a sequential injection analysis manifold for the colorimetric determination of lead in water samples is described The concentration of lead was assessed from its catalytic effect on the reaction of resazurine reduction caused by sulfide in an alkali medium. To that effect, the reaction zone was stopped at the detector, and the time interval required for the attainment of an absorbance decrease of 0.800 at the wavelength of 610 nm was estimated. Interference of other transition metals of the samples was minimized by adding potassium iodide to the sample and retaining the iodocomplexes formed in an on-line anionic resin (AGI X8). Elution was made with a 2 mol/L sodium hydroxide solution. The relationship [SIA] microg/L = 0.99 (+/- 0.11) x [ETAAS] microg/L + 0 (+/- 4) was obtained upon comparing the results given by the proposed system and by electrothermal atomization atomic absorption spectrometry (ETAAS) after the analysis of ten water samples. PMID:15116968

  9. Early prediction of pathological response in locally advanced rectal cancer based on sequential 18F-FDG PET

    PubMed Central

    HATT, MATHIEU; VAN STIPHOUT, RUUD; LE POGAM, ADRIEN; LAMMERING, GUIDO; VISVIKIS, DIMITRIS; LAMBIN, PHILIPPE

    2016-01-01

    Background The objectives of this study were to investigate the predictive value of sequential 18F-FDG PET scans for pathological tumor response grade (TRG) after preoperative chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC) and the impact of partial volume effects correction (PVC). Methods Twenty-eight LARC patients were included. Responders and non-responders status were determined in histopathology. PET indices [SUV max and mean, volume and total lesion glycolysis (TLG)] at baseline and their evolution after one and two weeks of PCRT were extracted by delineation of the PET images, with or without PVC. Their predictive value was investigated using Mann-Whitney-U tests and ROC analysis. Results Within baseline parameters, only SUVmean was correlated with response. No evolution after one week was predictive of the response, whereas after two weeks all the parameters except volume were, the best prediction being obtained with TLG (AUC 0.79, sensitivity 63%, specificity 92%). PVC had no significant impact on these results. Conclusion Several PET indices at baseline and their evolution after two weeks of PCRT are good predictors of response in LARC, with or without PVC, whereas results after one week are suboptimal. Best predictor was TLG reduction after two weeks, although baseline SUVmean had smaller but similar predictive power. PMID:22873767

  10. A general sequential Monte Carlo method based optimal wavelet filter: A Bayesian approach for extracting bearing fault features

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Sun, Shilong; Tse, Peter W.

    2015-02-01

    A general sequential Monte Carlo method, particularly a general particle filter, attracts much attention in prognostics recently because it is able to on-line estimate posterior probability density functions of the state functions used in a state space model without making restrictive assumptions. In this paper, the general particle filter is introduced to optimize a wavelet filter for extracting bearing fault features. The major innovation of this paper is that a joint posterior probability density function of wavelet parameters is represented by a set of random particles with their associated weights, which is seldom reported. Once the joint posterior probability density function of wavelet parameters is derived, the approximately optimal center frequency and bandwidth can be determined and be used to perform an optimal wavelet filtering for extracting bearing fault features. Two case studies are investigated to illustrate the effectiveness of the proposed method. The results show that the proposed method provides a Bayesian approach to extract bearing fault features. Additionally, the proposed method can be generalized by using different wavelet functions and metrics and be applied more widely to any other situation in which the optimal wavelet filtering is required.

  11. Rapid Access to 2,2'-Bithiazole-Based Copolymers via Sequential Palladium-Catalyzed C-H/C-X and C-H/C-H Coupling Reactions.

    PubMed

    Guo, Qiang; Jiang, Ruyong; Wu, Di; You, Jingsong

    2016-05-01

    A rapid access to 2,2'-bithiazole-based copolymers has been developed on the basis of the sequential palladium-catalyzed CH/CX and CH/CH coupling reactions. To assemble a "copolymer" through homopolymerization, a type of symmetric A-B-A-type building block is designed as the monomer and prepared via the regioselective C5H arylation of thiazole. A PdCl2 /CuCl-cocatalyzed oxidative CH/CH homopolymerization has been established to afford the 2,2'-bithiazole-based copolymers with high Mn (up to 69400). The current protocol features atom- and step-economy and exhibits a potential in the highly efficient construction of conjugated copolymers. PMID:27000723

  12. Classification of CMEs Based on Their Dynamics

    NASA Astrophysics Data System (ADS)

    Nicewicz, J.; Michalek, G.

    2016-05-01

    A large set of coronal mass ejections CMEs (6621) has been selected to study their dynamics seen with the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) field of view (LFOV). These events were selected based on having at least six height-time measurements so that their dynamic properties, in the LFOV, can be evaluated with reasonable accuracy. Height-time measurements (in the SOHO/LASCO catalog) were used to determine the velocities and accelerations of individual CMEs at successive distances from the Sun. Linear and quadratic functions were fitted to these data points. On the basis of the best fits to the velocity data points, we were able to classify CMEs into four groups. The types of CMEs do not only have different dynamic behaviors but also different masses, widths, velocities, and accelerations. We also show that these groups of events are initiated by different onset mechanisms. The results of our study allow us to present a consistent classification of CMEs based on their dynamics.

  13. Motif-Optimized Subtype A HIV Envelope-based DNA Vaccines Rapidly Elicit Neutralizing Antibodies When Delivered Sequentially

    PubMed Central

    Pissani, Franco; Malherbe, Delphine C.; Robins, Harlan; DeFilippis, Victor R.; Park, Byung; Sellhorn, George; Stamatatos, Leonidas; Overbaugh, Julie; Haigwood, Nancy L.

    2012-01-01

    HIV-1 infection results in the development of a diverging quasispecies unique to each infected individual. Envelope (Env)-specific neutralizing antibodies (NAbs) typically develop over months to years after infection and initially are limited to the infecting virus. In some subjects, antibody responses develop that neutralize heterologous isolates (HNAbs), a phenomenon termed broadening of the NAb response. Studies of co-crystalized antibodies and proteins have facilitated the identification of some targets of broadly neutralizing monoclonal antibodies (NmAbs) capable of neutralizing many or most heterologous viruses; however, the ontogeny of these antibodies in vivo remains elusive. We hypothesize that Env protein escape variants stimulate broad NAb development in vivo and could generate such NAbs when used as immunogens. Here we test this hypothesis in rabbits using HIV Env vaccines featuring: (1) use of individual quasispecies env variants derived from an HIV-1 subtype A-infected subject exhibiting high levels of NAbs within the first year of infection that increased and broadened with time; (2) motif optimization of envs to enhance in vivo expression of DNA formulated as vaccines; and (3) a combined DNA plus protein boosting regimen. Vaccines consisted of multiple env variants delivered sequentially and a simpler regimen that utilized only the least and most divergent clones. The simpler regimen was as effective as the more complex approach in generating modest HNAbs and was more efficient when modified, motif-optimized DNA was used in combination with trimeric gp140 protein. This is a rationally designed strategy that facilitates future vaccine design by addressing the difficult problem of generating HNAbs to HIV by empirically testing the immunogenicity of naturally occurring quasispecies env variants. PMID:22749601

  14. Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps.

    PubMed

    Singharoy, Abhishek; Teo, Ivan; McGreevy, Ryan; Stone, John E; Zhao, Jianhua; Schulten, Klaus

    2016-01-01

    Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services. PMID:27383269

  15. Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps

    PubMed Central

    Singharoy, Abhishek; Teo, Ivan; McGreevy, Ryan; Stone, John E; Zhao, Jianhua; Schulten, Klaus

    2016-01-01

    Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services. DOI: http://dx.doi.org/10.7554/eLife.16105.001 PMID:27383269

  16. Keystroke Dynamics-Based Credential Hardening Systems

    NASA Astrophysics Data System (ADS)

    Bartlow, Nick; Cukic, Bojan

    abstract Keystroke dynamics are becoming a well-known method for strengthening username- and password-based credential sets. The familiarity and ease of use of these traditional authentication schemes combined with the increased trustworthiness associated with biometrics makes them prime candidates for application in many web-based scenarios. Our keystroke dynamics system uses Breiman’s random forests algorithm to classify keystroke input sequences as genuine or imposter. The system is capable of operating at various points on a traditional ROC curve depending on application-specific security needs. As a username/password authentication scheme, our approach decreases the system penetration rate associated with compromised passwords up to 99.15%. Beyond presenting results demonstrating the credential hardening effect of our scheme, we look into the notion that a user’s familiarity to components of a credential set can non-trivially impact error rates.

  17. Automated microbial metabolism laboratory. [design of advanced labeled release experiment based on single addition of soil and multiple sequential additions of media into test chambers

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The design and rationale of an advanced labeled release experiment based on single addition of soil and multiple sequential additions of media into each of four test chambers are outlined. The feasibility for multiple addition tests was established and various details of the methodology were studied. The four chamber battery of tests include: (1) determination of the effect of various atmospheric gases and selection of that gas which produces an optimum response; (2) determination of the effect of incubation temperature and selection of the optimum temperature for performing Martian biochemical tests; (3) sterile soil is dosed with a battery of C-14 labeled substrates and subjected to experimental temperature range; and (4) determination of the possible inhibitory effects of water on Martian organisms is performed initially by dosing with 0.01 ml and 0.5 ml of medium, respectively. A series of specifically labeled substrates are then added to obtain patterns in metabolic 14CO2 (C-14)O2 evolution.

  18. Synthesis, physical characterization, and biological performance of sequential homointerpenetrating polymer network sponges based on poly(2-hydroxyethyl methacrylate).

    PubMed

    Lou, X; Vijayasekaran, S; Chirila, T V; Maley, M A; Hicks, C R; Constable, I J

    1999-12-01

    A limitation in the use of hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) sponges as implantable devices is their inherently poor mechanical strength. This precludes proper surgical manipulation, especially in the eye where the size of the implant is usually small. In this study a new method was developed to produce mechanically stronger PHEMA sponges. Sequential homointerpenetrating polymer network (homo-IPN) sponges were made by using HEMA as the precursor for generating both the first network and the successive interpenetrated networks. Following the formation of network I, the sponge was squeezed to remove the interstitial water, soaked in the second monomer (also HEMA), and squeezed again to remove the excess monomer from the pores before being subjected to the second polymerization leading to the formation of network II. Two two-component IPN sponges (K2 and K4) with increasing HEMA content in the network II and a three-component IPN sponge (K3) were produced, and their properties were compared to those of a homopolymer PHEMA sponge (control). Apart from elongation, the tensile properties were all significantly enhanced in the IPN sponges; the water content was the same as in the control sponge, except for sponge K4, which was lower. Light microscopy revealed similar pore morphologies of the control and IPN sponges K2 and K3, and the majority of the pores were around 25 microm. Sponge K4 displayed smaller pores of around 10 microm. Cellular invasion into the sponges was examined in vitro (incubation with 3T3 fibroblasts) and in vivo (implantation in rabbit corneas). Although the in vitro assay detected a change in the cell behavior in the early stage of invasion, which was probably due to the formation of IPNs, such changes were not reflected in the longer term in vivo experiment. There was a proper integration of sponges K2 and K3 with the corneal stroma, but much less cellular invasion and no neovascularization in sponge K4. We concluded that IPN

  19. Exploring the Behavioural Patterns in Project-Based Learning with Online Discussion: Quantitative Content Analysis and Progressive Sequential Analysis

    ERIC Educational Resources Information Center

    Hou, Huei-Tse

    2010-01-01

    Project-based learning using online learning environments is becoming increasingly popular. To in-depth explore the behavioural patterns and limitations faced by students in project-based learning where online forums are used. This study conducted an empirical case study of an online project-based learning activity in a management course, in which…

  20. Quantum union bounds for sequential projective measurements

    NASA Astrophysics Data System (ADS)

    Gao, Jingliang

    2015-11-01

    We present two quantum union bounds for sequential projective measurements. These bounds estimate the disturbance accumulation and probability of outcomes when the measurements are performed sequentially. These results are based on a trigonometric representation of quantum states and should have wide application in quantum information theory for information-processing tasks such as communication and state discrimination, and perhaps even in the analysis of quantum algorithms.

  1. Passive Baited Sequential Filth Fly Trap

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Filth fly control measures may be optimized with a better understanding of fly population dynamics measured throughout the day. We describe the modification of a commercial motorized sequential mosquito trap to accept liquid odorous bait and leverage a classic inverted cone design to passively confi...

  2. Sequential inductive learning

    SciTech Connect

    Gratch, J.

    1996-12-31

    This article advocates a new model for inductive learning. Called sequential induction, it helps bridge classical fixed-sample learning techniques (which are efficient but difficult to formally characterize), and worst-case approaches (which provide strong statistical guarantees but are too inefficient for practical use). Learning proceeds as a sequence of decisions which are informed by training data. By analyzing induction at the level of these decisions, and by utilizing the only enough data to make each decision, sequential induction provides statistical guarantees but with substantially less data than worst-case methods require. The sequential inductive model is also useful as a method for determining a sufficient sample size for inductive learning and as such, is relevant to learning problems where the preponderance of data or the cost of gathering data precludes the use of traditional methods.

  3. Optimal caching algorithm based on dynamic programming

    NASA Astrophysics Data System (ADS)

    Guo, Changjie; Xiang, Zhe; Zhong, Yuzhuo; Long, Jidong

    2001-07-01

    With the dramatic growth of multimedia streams, the efficient distribution of stored videos has become a major concern. There are two basic caching strategies: the whole caching strategy and the caching strategy based on layered encoded video, the latter can satisfy the requirement of the highly heterogeneous access to the Internet. Conventional caching strategies assign each object a cache gain by calculating popularity or density popularity, and determine which videos and which layers should be cached. In this paper, we first investigate the delivery model of stored video based on proxy, and propose two novel caching algorithms, DPLayer (for layered encoded caching scheme) and DPWhole (for whole caching scheme) for multimedia proxy caching. The two algorithms are based on the resource allocation model of dynamic programming to select the optimal subset of objects to be cached in proxy. Simulation proved that our algorithms achieve better performance than other existing schemes. We also analyze the computational complexity and space complexity of the algorithms, and introduce a regulative parameter to compress the states space of the dynamic programming problem and reduce the complexity of algorithms.

  4. Dynamics-based centrality for directed networks

    NASA Astrophysics Data System (ADS)

    Masuda, Naoki; Kori, Hiroshi

    2010-11-01

    Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

  5. Sequential elution process

    DOEpatents

    Kingsley, Ilse S.

    1987-01-01

    A process and apparatus for the separation of complex mixtures of carbonaceous material by sequential elution with successively stronger solvents. In the process, a column containing glass beads is maintained in a fluidized state by a rapidly flowing stream of a weak solvent, and the sample is injected into this flowing stream such that a portion of the sample is dissolved therein and the remainder of the sample is precipitated therein and collected as a uniform deposit on the glass beads. Successively stronger solvents are then passed through the column to sequentially elute less soluble materials.

  6. Sequential elution process

    DOEpatents

    Kingsley, I.S.

    1987-01-06

    A process and apparatus are disclosed for the separation of complex mixtures of carbonaceous material by sequential elution with successively stronger solvents. In the process, a column containing glass beads is maintained in a fluidized state by a rapidly flowing stream of a weak solvent, and the sample is injected into this flowing stream such that a portion of the sample is dissolved therein and the remainder of the sample is precipitated therein and collected as a uniform deposit on the glass beads. Successively stronger solvents are then passed through the column to sequentially elute less soluble materials. 1 fig.

  7. Dynamic Digital Channelizer Based on Spectrum Sensing.

    PubMed

    Hu, Junpeng; Zuo, Zhen; Huang, Zhiping; Dong, Zhi

    2015-01-01

    The ability to efficiently channelize a received signal with dynamic sub-channel bandwidths is a key requirement of software defined radio (SDR) systems. The digital channelizer, which is used to split the received signal into a number of sub-channels, plays an important role in SDR systems. In this paper, a design of dynamic digital channelizer is presented. The proposed method is novel in that it employs a cosine modulated filter bank (CMFB) to divide the received signal into multiple frequency sub-bands and a spectrum sensing technique, which is mostly used in cognitive radio, is introduced to detect the presence of signal of each sub-band. The method of spectrum sensing is carried out based on the eigenvalues of covariance matrix of received signal. The ratio of maximum-minimum eigenvalue of each sub-band is vulnerable to noise fluctuation. This paper suggests an optimized method to calculate the ratio of maximum-minimum eigenvalue. The simulation results imply that the design of digital channelizer can effectively separate the received signal with dynamically changeable sub-channel signals. PMID:26308210

  8. Skyrmion-Based Dynamic Magnonic Crystal.

    PubMed

    Ma, Fusheng; Zhou, Yan; Braun, H B; Lew, W S

    2015-06-10

    A linear array of periodically spaced and individually controllable skyrmions is introduced as a magnonic crystal. It is numerically demonstrated that skyrmion nucleation and annihilation can be accurately controlled by a nanosecond spin polarized current pulse through a nanocontact. Arranged in a periodic array, such nanocontacts allow the creation of a skyrmion lattice that causes a periodic modulation of the waveguide's magnetization, which can be dynamically controlled by changing either the strength of an applied external magnetic field or the density of the injected spin current through the nanocontacts. The skyrmion diameter is highly dependent on both the applied field and the injected current. This implies tunability of the lowest band gap as the skyrmion diameter directly affects the strength of the pinning potential. The calculated magnonic spectra thus exhibit tunable allowed frequency bands and forbidden frequency bandgaps analogous to that of conventional magnonic crystals where, in contrast, the periodicity is structurally induced and static. In the dynamic magnetic crystal studied here, it is possible to dynamically turn on and off the artificial periodic structure, which allows switching between full rejection and full transmission of spin waves in the waveguide. These findings should stimulate further research activities on multiple functionalities offered by magnonic crystals based on periodic skyrmion lattices. PMID:25989181

  9. Sequential growth and monitoring of a polypyrrole actuator system

    NASA Astrophysics Data System (ADS)

    Sarrazin, J. C.; Mascaro, Stephen A.

    2014-03-01

    Electroactive polymers (EAPs) have emerged as viable materials in sensing and actuating applications, but the capability to mimic the structure and function of natural muscle is increased due to their ability to permit additional, sequential synthesis steps between stages of actuation. Current work is improving upon the mechanical performance in terms of achievable stresses, strains, and strain rates, but issues still remain with actuator lifetime and adaptability. This work seeks to create a bioinspired polymer actuation system that can be monitored using state estimation and adjusted in vivo during operation. The novel, time-saving process of sequential growth was applied to polymer actuator systems for the initial growth, as well as additional growth steps after actuation cycles. Synthesis of conducting polymers on a helical metal electrode directs polymer shape change during actuation, assists in charge distribution along the polymer for actuation, and as is described in this work, constructs a constant working electrode/polymer connection during operation which allows sequential polymer growth based on a performance need. The polymer system is monitored by means of a reduced-order, state estimation model that works between growth and actuation cycles. In this case, actuator stress is improved between growth cycles. The ability for additional synthesis of the polymer actuator not only creates an actuator system that can be optimized based on demand, but creates a dynamic actuator system that more closely mimics natural muscle capability.

  10. Passive Baited Sequential Filth Fly Trap.

    PubMed

    Aldridge, Robert L; Britch, Seth C; Snelling, Melissa; Gutierez, Arturo; White, Gregory; Linthicum, Kenneth J

    2015-09-01

    Filth fly control measures may be optimized with a better understanding of fly population dynamics measured throughout the day. We describe the modification of a commercial motorized sequential mosquito trap to accept liquid odorous bait and leverage a classic inverted-cone design to passively confine flies in 8 modified collection bottles corresponding to 8 intervals. Efficacy trials in a hot-arid desert environment indicate no significant difference (P  =  0.896) between the modified sequential trap and a Rid-Max® fly trap. PMID:26375911

  11. Dynamic plasmapause model based on THEMIS measurements

    NASA Astrophysics Data System (ADS)

    Liu, X.; Liu, W.; Cao, J. B.; Fu, H. S.; Yu, J.; Li, X.

    2015-12-01

    This paper presents a dynamic plasmapause location model established based on 5 years of Time History of Events and Macroscale Interactions during Substorms (THEMIS) measurements from 2009 to 2013. In total, 5878 plasmapause crossing events are identified, sufficiently covering all 24 magnetic local time (MLT) sectors. Based on this plasmapause crossing database, we investigate the correlations between plasmapause locations with solar wind parameters and geomagnetic indices. Input parameters for the best fits are obtained for different MLT sectors, and finally, we choose five input parameters to build a plasmapause location model, including 5 min-averaged SYM-H, AL, and AU indices as well as hourly-averaged AE and Kp indices. two out-of-sample comparisons on the evolution of the plasmapause is shown during two magnetic storms, demonstrating good agreement between model results and observations. Two major advantages are achieved by this model. First, this model provides plasmapause locations at 24 MLT sectors, still providing good consistency with observations. Second, this model is able to reproduce dynamic variations of the plasmapause on timescales as short as 5 min.

  12. Motion detection based on recurrent network dynamics

    PubMed Central

    Joukes, Jeroen; Hartmann, Till S.; Krekelberg, Bart

    2014-01-01

    The detection of visual motion requires temporal delays to compare current with earlier visual input. Models of motion detection assume that these delays reside in separate classes of slow and fast thalamic cells, or slow and fast synaptic transmission. We used a data-driven modeling approach to generate a model that instead uses recurrent network dynamics with a single, fixed temporal integration window to implement the velocity computation. This model successfully reproduced the temporal response dynamics of a population of motion sensitive neurons in macaque middle temporal area (MT) and its constituent parts matched many of the properties found in the motion processing pathway (e.g., Gabor-like receptive fields (RFs), simple and complex cells, spatially asymmetric excitation and inhibition). Reverse correlation analysis revealed that a simplified network based on first and second order space-time correlations of the recurrent model behaved much like a feedforward motion energy (ME) model. The feedforward model, however, failed to capture the full speed tuning and direction selectivity properties based on higher than second order space-time correlations typically found in MT. These findings support the idea that recurrent network connectivity can create temporal delays to compute velocity. Moreover, the model explains why the motion detection system often behaves like a feedforward ME network, even though the anatomical evidence strongly suggests that this network should be dominated by recurrent feedback. PMID:25565992

  13. The sequential trauma score - a new instrument for the sequential mortality prediction in major trauma*

    PubMed Central

    2010-01-01

    Background There are several well established scores for the assessment of the prognosis of major trauma patients that all have in common that they can be calculated at the earliest during intensive care unit stay. We intended to develop a sequential trauma score (STS) that allows prognosis at several early stages based on the information that is available at a particular time. Study design In a retrospective, multicenter study using data derived from the Trauma Registry of the German Trauma Society (2002-2006), we identified the most relevant prognostic factors from the patients basic data (P), prehospital phase (A), early (B1), and late (B2) trauma room phase. Univariate and logistic regression models as well as score quality criteria and the explanatory power have been calculated. Results A total of 2,354 patients with complete data were identified. From the patients basic data (P), logistic regression showed that age was a significant predictor of survival (AUCmodel p, area under the curve = 0.63). Logistic regression of the prehospital data (A) showed that blood pressure, pulse rate, Glasgow coma scale (GCS), and anisocoria were significant predictors (AUCmodel A = 0.76; AUCmodel P + A = 0.82). Logistic regression of the early trauma room phase (B1) showed that peripheral oxygen saturation, GCS, anisocoria, base excess, and thromboplastin time to be significant predictors of survival (AUCmodel B1 = 0.78; AUCmodel P +A + B1 = 0.85). Multivariate analysis of the late trauma room phase (B2) detected cardiac massage, abbreviated injury score (AIS) of the head ≥ 3, the maximum AIS, the need for transfusion or massive blood transfusion, to be the most important predictors (AUCmodel B2 = 0.84; AUCfinal model P + A + B1 + B2 = 0.90). The explanatory power - a tool for the assessment of the relative impact of each segment to mortality - is 25% for P, 7% for A, 17% for B1 and 51% for B2. A spreadsheet for the easy calculation of the sequential trauma score is

  14. Sequential Dependencies in Driving

    ERIC Educational Resources Information Center

    Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

    2012-01-01

    The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

  15. A high-performance ground-based prototype of horn-type sequential vegetable production facility for life support system in space

    NASA Astrophysics Data System (ADS)

    Fu, Yuming; Liu, Hui; Shao, Lingzhi; Wang, Minjuan; Berkovich, Yu A.; Erokhin, A. N.; Liu, Hong

    2013-07-01

    Vegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight. Here we developed a ground-based prototype of horn-type sequential vegetable production facility, named Horn-type Producer (HTP), which was capable of simulating the microgravity effect and the continuous cultivation of leaf-vegetables on root modules. The growth chamber of the facility had a volume of 0.12 m3, characterized by a three-stage space expansion with plant growth. The planting surface of 0.154 m2 was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved forward with plant growth. The total illuminated crop area of 0.567 m2 was provided by a combination of red and white light emitting diodes on the internal surfaces. In tests with a 24-h photoperiod, the productivity of the HTP at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week. Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent. Furthermore, the efficiency of the HTP, based on the Q-criterion, was 7 × 10-4 g2 m-3 J-1. These results show that the HTP exhibited high productivity, stable quality, and good efficiency in the process of planting lettuce, indicative of an interesting design for space vegetable production.

  16. An Approach to Characterizing the Complicated Sequential Metabolism of Salidroside in Rats.

    PubMed

    Luo, Zhiqiang; Ma, Xiaoyun; Liu, Yang; Lu, Lina; Yang, Ruirui; Yu, Guohua; Sun, Mohan; Xin, Shaokun; Tian, Simin; Chen, Xinjing; Zhao, Haiyu

    2016-01-01

    Metabolic study of bioactive compounds that undergo a dynamic and sequential process of metabolism is still a great challenge. Salidroside, one of the most active ingredients of Rhodiola crenulata, can be metabolized in different sites before being absorbed into the systemic blood stream. This study proposed an approach for describing the sequential biotransformation process of salidroside based on comparative analysis. In vitro incubation, in situ closed-loop and in vivo blood sampling were used to determine the relative contribution of each site to the total metabolism of salidroside. The results showed that salidroside was stable in digestive juice, and it was metabolized primarily by the liver and the intestinal flora and to a lesser extent by the gut wall. The sequential metabolism method described in this study could be a general approach to characterizing the metabolic routes in the digestive system for natural products. PMID:27248984

  17. Spatiotemporal-atlas-based dynamic speech imaging

    NASA Astrophysics Data System (ADS)

    Fu, Maojing; Woo, Jonghye; Liang, Zhi-Pei; Sutton, Bradley P.

    2016-03-01

    Dynamic magnetic resonance imaging (DS-MRI) has been recognized as a promising method for visualizing articulatory motion of speech in scientific research and clinical applications. However, characterization of the gestural and acoustical properties of the vocal tract remains a challenging task for DS-MRI because it requires: 1) reconstructing high-quality spatiotemporal images by incorporating stronger prior knowledge; and 2) quantitatively interpreting the reconstructed images that contain great motion variability. This work presents a novel imaging method that simultaneously meets both requirements by integrating a spatiotemporal atlas into a Partial Separability (PS) model-based imaging framework. Through the use of an atlas-driven sparsity constraint, this method is capable of capturing high-quality articulatory dynamics at an imaging speed of 102 frames per second and a spatial resolution of 2.2 × 2.2 mm2. Moreover, the proposed method enables quantitative characterization of variability of speech motion, compared to the generic motion pattern across all subjects, through the spatial residual components.

  18. Floc-based sequential partial nitritation and anammox at full scale with contrasting N2O emissions.

    PubMed

    Desloover, Joachim; De Clippeleir, Haydée; Boeckx, Pascal; Du Laing, Gijs; Colsen, Joop; Verstraete, Willy; Vlaeminck, Siegfried E

    2011-04-01

    New Activated Sludge (NAS(®)) is a hybrid, floc-based nitrogen removal process without carbon addition, based on the control of sludge retention times (SRT) and dissolved oxygen (DO) levels. The aim of this study was to examine the performance of a retrofitted four-stage NAS(®) plant, including on-line measurements of greenhouse gas emissions (N(2)O and CH(4)). The plant treated anaerobically digested industrial wastewater, containing 264 mg N L(-1), 1154 mg chemical oxygen demand (COD) L(-1) and an inorganic carbon alkalinity of 34 meq L(-1). The batch-fed partial nitritation step received an overall nitrogen loading rate of 0.18-0.22 kg N m(-3) d(-1), thereby oxidized nitrogen to nitrite (45-47%) and some nitrate (13-15%), but also to N(2)O (5.1-6.6%). This was achieved at a SRT of 1.7 d and DO around 1.0 mg O(2) L(-1). Subsequently, anammox, denitrification and nitrification compartments were followed by a final settler, at an overall SRT of 46 d. None of the latter three reactors emitted N(2)O. In the anammox step, 0.26 kg N m(-3) d(-1) was removed, with an estimated contribution of 71% by the genus Kuenenia, which constituted 3.1% of the biomass. Overall, a nitrogen removal efficiency of 95% was obtained, yielding a dischargeable effluent. Retrofitting floc-based nitrification/denitrification with carbon addition to NAS(®) allowed to save 40% of the operational wastewater treatment costs. Yet, a decrease of the N(2)O emissions by about 50% is necessary in order to obtain a CO(2) neutral footprint. The impact of emitted CH(4) was 20 times lower. PMID:21440280

  19. Sequential digital elevation models of active lava flows from ground-based stereo time-lapse imagery

    NASA Astrophysics Data System (ADS)

    James, M. R.; Robson, S.

    2014-11-01

    We describe a framework for deriving sequences of digital elevation models (DEMs) for the analysis of active lava flows using oblique stereo-pair time-lapse imagery. A photo-based technique was favoured over laser-based alternatives due to low equipment cost, high portability and capability for network expansion, with images of advancing flows captured by digital SLR cameras over durations of up to several hours. However, under typical field scale scenarios, relative camera orientations cannot be rigidly maintained (e.g. through the use of a stereo bar), preventing the use of standard stereo time-lapse processing software. Thus, we trial semi-automated DEM-sequence workflows capable of handling the small camera motions, variable image quality and restricted photogrammetric control that result from the practicalities of data collection at remote and hazardous sites. The image processing workflows implemented either link separate close-range photogrammetry and traditional stereo-matching software, or are integrated in a single software package based on structure-from-motion (SfM). We apply these techniques in contrasting case studies from Kilauea volcano, Hawaii and Mount Etna, Sicily, which differ in scale, duration and image texture. On Kilauea, the advance direction of thin fluid lava lobes was difficult to forecast, preventing good distribution of control. Consequently, volume changes calculated through the different workflows differed by ∼10% for DEMs (over ∼30 m2) that were captured once a minute for 37 min. On Mt. Etna, more predictable advance (∼3 m h-1 for ∼3 h) of a thicker, more viscous lava allowed robust control to be deployed and volumetric change results were generally within 5% (over ∼500 m2). Overall, the integrated SfM software was more straightforward to use and, under favourable conditions, produced results comparable to those from the close-range photogrammetry pipeline. However, under conditions with limited options for photogrammetric

  20. Dynamic visual cryptography based on chaotic oscillations

    NASA Astrophysics Data System (ADS)

    Petrauskiene, Vilma; Palivonaite, Rita; Aleksa, Algiment; Ragulskis, Minvydas

    2014-01-01

    Dynamic visual cryptography scheme based on chaotic oscillations is proposed in this paper. Special computational algorithms are required for hiding the secret image in the cover moiré grating, but the decryption of the secret is completely visual. The secret image is leaked in the form of time-averaged geometric moiré fringes when the cover image is oscillated by a chaotic law. The relationship among the standard deviation of the stochastic time variable, the pitch of the moiré grating and the pixel size ensuring visual decryption of the secret is derived. The parameters of these chaotic oscillations must be carefully preselected before the secret image is leaked from the cover image. Several computational experiments are used to illustrate the functionality and the applicability of the proposed image hiding technique.

  1. Partial discharge localization in power transformers based on the sequential quadratic programming-genetic algorithm adopting acoustic emission techniques

    NASA Astrophysics Data System (ADS)

    Liu, Hua-Long; Liu, Hua-Dong

    2014-10-01

    Partial discharge (PD) in power transformers is one of the prime reasons resulting in insulation degradation and power faults. Hence, it is of great importance to study the techniques of the detection and localization of PD in theory and practice. The detection and localization of PD employing acoustic emission (AE) techniques, as a kind of non-destructive testing, plus due to the advantages of powerful capability of locating and high precision, have been paid more and more attention. The localization algorithm is the key factor to decide the localization accuracy in AE localization of PD. Many kinds of localization algorithms exist for the PD source localization adopting AE techniques including intelligent and non-intelligent algorithms. However, the existed algorithms possess some defects such as the premature convergence phenomenon, poor local optimization ability and unsuitability for the field applications. To overcome the poor local optimization ability and easily caused premature convergence phenomenon of the fundamental genetic algorithm (GA), a new kind of improved GA is proposed, namely the sequence quadratic programming-genetic algorithm (SQP-GA). For the hybrid optimization algorithm, SQP-GA, the sequence quadratic programming (SQP) algorithm which is used as a basic operator is integrated into the fundamental GA, so the local searching ability of the fundamental GA is improved effectively and the premature convergence phenomenon is overcome. Experimental results of the numerical simulations of benchmark functions show that the hybrid optimization algorithm, SQP-GA, is better than the fundamental GA in the convergence speed and optimization precision, and the proposed algorithm in this paper has outstanding optimization effect. At the same time, the presented SQP-GA in the paper is applied to solve the ultrasonic localization problem of PD in transformers, then the ultrasonic localization method of PD in transformers based on the SQP-GA is proposed. And

  2. Sequential fractionation of grape seeds into oils, polyphenols, and procyanidins via a single system employing CO2-based fluids.

    PubMed

    Ashraf-Khorassani, Mehdi; Taylor, Larry Thomas

    2004-05-01

    Pure supercritical CO(2) was used to remove >95% of the oil from the grape seeds. Subcritical CO(2) modified with methanol was used for the extraction of monomeric polyphenols, whereas pure methanol was used for the extraction of polyphenolic dimers/trimers and procyanidins from grape seed. At optimum conditions, 40% methanol-modified CO(2) removed >79% of catechin and epicatechin from the grape seed. This extract was light yellow in color, and no higher molecular weight procyanidins were detected. Extraction of the same sample after removal of the oils and polyphenols, but now under enhanced solvent extraction conditions using methanol as a solvent, provided a dark red solution shown via electrospray ionization HPLC-MS to contain a relatively high concentration of procyanidins. The uniqueness of the study is attested to by the use of CO(2)-based fluids and the employment of a single instrumental extraction system. PMID:15113138

  3. Antidepressant Monotherapy versus Sequential Pharmacotherapy and Mindfulness-Based Cognitive Therapy, or Placebo, for Relapse Prophylaxis in Recurrent Depression

    PubMed Central

    Segal, Zindel V.; Bieling, Peter; Young, Trevor; MacQueen, Glenda; Cooke, Robert; Martin, Lawrence; Bloch, Richard; Levitan, Robert

    2012-01-01

    Context Mindfulness Based Cognitive Therapy (MBCT) is a group-based psychosocial intervention designed to enhance self-management of prodromal symptoms associated with depressive relapse. Objective To compare rates of relapse in remitted depressed patients receiving MBCT against maintenance antidepressant pharmacotherapy, the current standard of care Design Patients who met remission criteria following 8 months of algorithm informed antidepressant treatment were randomized to either: Maintenance Antidepressant Medication (M-ADM), MBCT or placebo (PLA) and were followed for 18 months. Setting Outpatient clinics at the Centre for Addiction and Mental Health, Toronto and St. Joseph’s Healthcare, Hamilton. Participants One hundred sixty patients aged 18 to 65 meeting DSM-IV for major depressive disorder with a minimum of 2 past episodes. Of these, 84 achieved remission (52.5%) and were assigned to one of the 3 study conditions. Interventions Remitted patients either discontinued their antidepressants and attended eight weekly group sessions of MBCT, continued on their therapeutic dose of antidepressant medication or discontinued active medication onto placebo. Main Outcome Measure Relapse was defined as a return, for at least 2 weeks, of symptoms sufficient to meet the criteria for major depression on Module A of the SCID. Results Intention to treat analyses revealed a significant interaction between the quality of acute phase remission and subsequent prevention of relapse in randomized patients (p = .03). Among unstable remitters (defined as 1 or more HRSD >7 during remission) patients in both MBCT and M-ADM showed a 73% decrease in hazard compared to PLA (p = .03), whereas for stable remitters (all HRSD ≤ 7 during remission) there were no group differences in survival. Findings remained significant after accounting for the effects of past depressive episodes on relapse. Conclusion For depressed patients who are unwilling or unable to tolerate long term

  4. Beyond evidence-based data: scientific rationale and tumor behavior to drive sequential and personalized therapeutic strategies for the treatment of metastatic renal cell carcinoma

    PubMed Central

    Badalamenti, Giuseppe; Rizzo, Sergio; Pantuso, Gianni; Natoli, Clara; Russo, Antonio

    2016-01-01

    The recent advances in identification of the molecular mechanisms related to tumorigenesis and angiogenesis, along with the understanding of molecular alterations involved in renal cell carcinoma (RCC) pathogenesis, has allowed the development of several new drugs which have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). This process has resulted in clinically significant improvements in median overall survival and an increasing number of patients undergoes two or even three lines of therapy. Therefore, it is necessary a long-term perspective of the treatment: planning a sequential and personalized therapeutic strategy to improve clinical outcome, the potential to achieve long-term response, and to preserve quality of life (QOL), minimizing treatment-related toxicity and transforming mRCC into a chronically treatable condition. Because of the challenges still encountered to draw an optimal therapeutic sequence, the main focus of this article will be to propose the optimal sequencing of existing, approved, oral targeted agents for the treatment of mRCC using evidence-based data along with the knowledge available on the tumor behavior and mechanisms of resistance to anti-angiogenic treatment to provide complementary information and to help the clinicians to maximize the effectiveness of targeted agents in the treatment of mRCC. PMID:26872372

  5. Synthesis and Application of an Aldazine-Based Fluorescence Chemosensor for the Sequential Detection of Cu2+ and Biological Thiols in Aqueous Solution and Living Cells

    PubMed Central

    Jia, Hongmin; Yang, Ming; Meng, Qingtao; He, Guangjie; Wang, Yue; Hu, Zhizhi; Zhang, Run; Zhang, Zhiqiang

    2016-01-01

    A fluorescence chemosensor, 2-hydroxy-1-naphthaldehyde azine (HNA) was designed and synthesized for sequential detection of Cu2+ and biothiols. It was found that HNA can specifically bind to Cu2+ with 1:1 stoichiometry, accompanied with a dramatic fluorescence quenching and a remarkable bathochromic-shift of the absorbance peak in HEPES buffer. The generated HNA-Cu2+ ensemble displayed a “turn-on” fluorescent response specific for biothiols (Hcy, Cys and GSH) based on the displacement approach, giving a remarkable recovery of fluorescence and UV-Vis spectra. The detection limits of HNA-Cu2+ to Hcy, Cys and GSH were estimated to be 1.5 μM, 1.0 μM and 0.8 μM, respectively, suggesting that HNA-Cu2+ is sensitive enough for the determination of thiols in biological systems. The biocompatibility of HNA towards A549 human lung carcinoma cell, was evaluated by an MTT assay. The capability of HNA-Cu2+ to detect biothiols in live A549 cells was then demonstrated by a microscopy fluorescence imaging assay. PMID:26761012

  6. Dynamics of Random Sequential Adsorption (RSA) of linear chains consisting of n circular discs - Role of aspect ratio and departure from convexity

    NASA Astrophysics Data System (ADS)

    Shelke, Pradip B.; Limaye, A. V.

    2015-07-01

    We study Random Sequential Adsorption (RSA) of linear chains consisting of n circular discs on a two-dimensional continuum substrate. The study has been carried out for n = 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 50, 70, 100 and 300. For all values of n, instantaneous coverage, Θ(t), in late time regime, is found to approach to jammed state coverage, Θ(∞), in a power law fashion, Θ(∞) - Θ(t) ~ t- p. It is observed that, with the increase in n, the exponent p goes on decreasing from the value 0.33 for n = 2 to the value 0.20 for n = 20 and then again starts rising to reach the value of 0.33 for large n. It is also found that for n ≤ 20, the exponent p has near perfect correlation with the coefficient of departure from convexity. On the other hand the jammed state coverage Θ(∞) is found to depend both on the coefficient of departure from convexity as well as on the aspect ratio of the chain.

  7. Sequential cloning of chromosomes

    SciTech Connect

    Lacks, S.A.

    1991-12-31

    A method for sequential cloning of chromosomal DNA and chromosomal DNA cloned by this method are disclosed. The method includes the selection of a target organism having a segment of chromosomal DNA to be sequentially cloned. A first DNA segment, having a first restriction enzyme site on either side. homologous to the chromosomal DNA to be sequentially cloned is isolated. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes.

  8. Batch sequential designs for computer experiments

    SciTech Connect

    Moore, Leslie M; Williams, Brian J; Loeppky, Jason L

    2009-01-01

    Computer models simulating a physical process are used in many areas of science. Due to the complex nature of these codes it is often necessary to approximate the code, which is typically done using a Gaussian process. In many situations the number of code runs available to build the Guassian process approximation is limited. When the initial design is small or the underlying response surface is complicated this can lead to poor approximations of the code output. In order to improve the fit of the model, sequential design strategies must be employed. In this paper we introduce two simple distance based metrics that can be used to augment an initial design in a batch sequential manner. In addition we propose a sequential updating strategy to an orthogonal array based Latin hypercube sample. We show via various real and simulated examples that the distance metrics and the extension of the orthogonal array based Latin hypercubes work well in practice.

  9. Sequential cloning of chromosomes

    DOEpatents

    Lacks, Sanford A.

    1995-07-18

    A method for sequential cloning of chromosomal DNA of a target organism is disclosed. A first DNA segment homologous to the chromosomal DNA to be sequentially cloned is isolated. The first segment has a first restriction enzyme site on either side. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism's chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction (class IIS) enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes.

  10. Sequential cloning of chromosomes

    DOEpatents

    Lacks, S.A.

    1995-07-18

    A method for sequential cloning of chromosomal DNA of a target organism is disclosed. A first DNA segment homologous to the chromosomal DNA to be sequentially cloned is isolated. The first segment has a first restriction enzyme site on either side. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction (class IIS) enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes. 9 figs.

  11. Visual vs Fully Automatic Histogram-Based Assessment of Idiopathic Pulmonary Fibrosis (IPF) Progression Using Sequential Multidetector Computed Tomography (MDCT)

    PubMed Central

    Colombi, Davide; Dinkel, Julien; Weinheimer, Oliver; Obermayer, Berenike; Buzan, Teodora; Nabers, Diana; Bauer, Claudia; Oltmanns, Ute; Palmowski, Karin; Herth, Felix; Kauczor, Hans Ulrich; Sverzellati, Nicola

    2015-01-01

    Objectives To describe changes over time in extent of idiopathic pulmonary fibrosis (IPF) at multidetector computed tomography (MDCT) assessed by semi-quantitative visual scores (VSs) and fully automatic histogram-based quantitative evaluation and to test the relationship between these two methods of quantification. Methods Forty IPF patients (median age: 70 y, interquartile: 62-75 years; M:F, 33:7) that underwent 2 MDCT at different time points with a median interval of 13 months (interquartile: 10-17 months) were retrospectively evaluated. In-house software YACTA quantified automatically lung density histogram (10th-90th percentile in 5th percentile steps). Longitudinal changes in VSs and in the percentiles of attenuation histogram were obtained in 20 untreated patients and 20 patients treated with pirfenidone. Pearson correlation analysis was used to test the relationship between VSs and selected percentiles. Results In follow-up MDCT, visual overall extent of parenchymal abnormalities (OE) increased in median by 5 %/year (interquartile: 0 %/y; +11 %/y). Substantial difference was found between treated and untreated patients in HU changes of the 40th and of the 80th percentiles of density histogram. Correlation analysis between VSs and selected percentiles showed higher correlation between the changes (Δ) in OE and Δ 40th percentile (r=0.69; p<0.001) as compared to Δ 80th percentile (r=0.58; p<0.001); closer correlation was found between Δ ground-glass extent and Δ 40th percentile (r=0.66, p<0.001) as compared to Δ 80th percentile (r=0.47, p=0.002), while the Δ reticulations correlated better with the Δ 80th percentile (r=0.56, p<0.001) in comparison to Δ 40th percentile (r=0.43, p=0.003). Conclusions There is a relevant and fully automatically measurable difference at MDCT in VSs and in histogram analysis at one year follow-up of IPF patients, whether treated or untreated: Δ 40th percentile might reflect the change in overall extent of lung

  12. FRF based joint dynamics modeling and identification

    NASA Astrophysics Data System (ADS)

    Mehrpouya, Majid; Graham, Eldon; Park, Simon S.

    2013-08-01

    Complex structures, such as machine tools, are comprised of several substructures connected to each other through joints to form the assembled structures. Joints can have significant contributions on the behavior of the overall assembly and ignoring joint effects in the design stage may result in considerable deviations from the actual dynamic behavior. The identification of joint dynamics enables us to accurately predict overall assembled dynamics by mathematically combining substructure dynamics through the equilibrium and compatibility conditions at the joint. The essence of joint identification is the determination of the difference between the measured overall dynamics and the rigidly coupled substructure dynamics. In this study, we investigate the inverse receptance coupling (IRC) method and the point-mass joint model, which considers the joint as lumped mass, damping and stiffness elements. The dynamic properties of the joint are investigated using both methods through a finite element (FE) simulation and experimental tests. `100

  13. Novel and dynamic evolution of equine infectious anemia virus genomic quasispecies associated with sequential disease cycles in an experimentally infected pony.

    PubMed Central

    Leroux, C; Issel, C J; Montelaro, R C

    1997-01-01

    We have investigated the genetic evolution of three functionally distinct regions of the equine infectious anemia virus (EIAV) genome (env, rev, and long terminal repeat) during recurring febrile episodes in a pony experimentally infected with a well-characterized reference biological clone designated EIAV(PV). Viral populations present in the plasma of an EIAV(PV)-infected pony during sequential febrile episodes (18, 34, 80, 106, and 337 days postinfection) were amplified from viral RNA, analyzed, and compared to the inoculated strain. The comparison of the viral quasispecies showed that the inoculated EIAV(PV) quasispecies were all represented during the first febrile episode, but entirely replaced at the time of the second febrile episode, and that new predominant quasispecies were associated with each subsequent cycle of disease. One of the more surprising results was the in vivo generation of large deletion (up to 15 amino acids) in the principal neutralizing domain (PND) of gp90 during the third febrile episode. This deletion did not alter the competence for in vitro replication as shown by the analysis of a env chimeric clone with a partially deleted PND and did not altered the fitness of the virus in vivo, since this partially deleted envelope became the major population during the fourth febrile episode. Finally, we showed that the amino acid mutations were not randomly distributed but delineated eight variables regions, V1 to V8, with V3 containing the PND region. These studies provide the first detailed description of the evolution of EIAV genomic quasispecies during persistent infection and reveal new insights into the genetics and potential mechanisms of lentivirus genomic variation. PMID:9371627

  14. Dynamic guide–target interactions contribute to sequential 2′-O-methylation by a unique archaeal dual guide box C/D sRNP

    PubMed Central

    Singh, Sanjay K.; Gurha, Priyatansh; Gupta, Ramesh

    2008-01-01

    Assembly and guide–target interaction of an archaeal box C/D-guide sRNP was investigated under various conditions by analyzing the lead (II)-induced cleavage of the guide RNA. Guide and target RNAs derived from Haloferax volcanii pre-tRNATrp were used with recombinant Methanocaldococcus jannaschii core proteins in the reactions. Core protein L7Ae binds differentially to C/D and C′/D′ motifs of the guide RNA, and interchanging the two motifs relative to the termini of the guide RNA did not affect L7Ae binding or sRNA function. L7Ae binding to the guide RNA exposes its D′-guide sequence first followed by the D guide. These exposures are reduced when aNop5p and aFib proteins are added. The exposed guide sequences did not pair with the target sequences in the presence of L7Ae alone. The D-guide sequence could pair with the target in the presence of L7Ae and aNop5p, suggesting a role of aNop5p in target recruitment and rearrangement of sRNA structure. aFib binding further stabilizes this pairing. After box C/D-guided modification, target–guide pairing at the D-guide sequence is disrupted, suggesting that each round of methylation may require some conformational change or reassembly of the RNP. Asymmetric RNPs containing only one L7Ae at either of the two box motifs can be assembled, but a functional RNP requires L7Ae at the box C/D motif. This arrangement resembles the asymmetric eukaryal snoRNP. Observations of initial D-guide–target pairing and the functional requirement for L7Ae at the box C/D motif are consistent with our previous report of the sequential 2′-O-methylations of the target RNA. PMID:18515549

  15. Development of Decision Making: Sequential versus Integrative Rules

    ERIC Educational Resources Information Center

    Jansen, Brenda R. J.; van Duijvenvoorde, Anna C. K.; Huizenga, Hilde M.

    2012-01-01

    Decisions can be made by applying a variety of decision-making rules--sequential rules in which decisions are based on a sequential evaluation of choice dimensions and the integrative normative rule in which decisions are based on an integration of choice dimensions. In this study, we investigated the developmental trajectory of such…

  16. Sequential products on effect algebras

    NASA Astrophysics Data System (ADS)

    Gudder, Stan; Greechie, Richard

    2002-02-01

    A sequential effect algebra (SEA) is an effect algebra on which a sequential product with natural properties is defined. The properties of sequential products on Hilbert space effect algebras are discussed. For a general SEA, relationships between sequential independence, coexistence and compatibility are given. It is shown that the sharp elements of a SEA form an orthomodular poset. The sequential center of a SEA is discussed and a characterization of when the sequential center is isomorphic to a fuzzy set system is presented. It is shown that the existence, of a sequential product is a strong restriction that eliminates many effect algebras from being SEA's. For example, there are no finite nonboolean SEA's, A measure of sharpness called the sharpness index is studied. The existence of horizontal sums of SEA's is characterized and examples of horizontal sums and tensor products are presented.

  17. Beyond Problem-Based Learning: Using Dynamic PBL in Chemistry

    ERIC Educational Resources Information Center

    Overton, Tina L.; Randles, Christopher A.

    2015-01-01

    This paper describes the development and implementation of a novel pedagogy, dynamic problem-based learning. The pedagogy utilises real-world problems that evolve throughout the problem-based learning activity and provide students with choice and different data sets. This new dynamic problem-based learning approach was utilised to teach…

  18. Reliable VLSI sequential controllers

    NASA Technical Reports Server (NTRS)

    Whitaker, S.; Maki, G.; Shamanna, M.

    1990-01-01

    A VLSI architecture for synchronous sequential controllers is presented that has attractive qualities for producing reliable circuits. In these circuits, one hardware implementation can realize any flow table with a maximum of 2(exp n) internal states and m inputs. Also all design equations are identical. A real time fault detection means is presented along with a strategy for verifying the correctness of the checking hardware. This self check feature can be employed with no increase in hardware. The architecture can be modified to achieve fail safe designs. With no increase in hardware, an adaptable circuit can be realized that allows replacement of faulty transitions with fault free transitions.

  19. Three-dimensional stochastic estimation of porosity distribution: Benefits of using ground-penetrating radar velocity tomograms in simulated-annealing-based or Bayesian sequential simulation approaches

    NASA Astrophysics Data System (ADS)

    Dafflon, B.; Barrash, W.

    2012-05-01

    Estimation of the three-dimensional (3-D) distribution of hydrologic properties and related uncertainty is a key for improved predictions of hydrologic processes in the subsurface. However it is difficult to gain high-quality and high-density hydrologic information from the subsurface. In this regard a promising strategy is to use high-resolution geophysical data (that are relatively sensitive to variations of a hydrologic parameter of interest) to supplement direct hydrologic information from measurements in wells (e.g., logs, vertical profiles) and then generate stochastic simulations of the distribution of the hydrologic property conditioned on the hydrologic and geophysical data. In this study we develop and apply this strategy for a 3-D field experiment in the heterogeneous aquifer at the Boise Hydrogeophysical Research Site and we evaluate how much benefit the geophysical data provide. We run high-resolution 3-D conditional simulations of porosity with both simulated-annealing-based and Bayesian sequential approaches using information from multiple intersecting crosshole gound-penetrating radar (GPR) velocity tomograms and neutron porosity logs. The benefit of using GPR data is assessed by investigating their ability, when included in conditional simulation, to predict porosity log data withheld from the simulation. Results show that the use of crosshole GPR data can significantly improve the estimation of porosity spatial distribution and reduce associated uncertainty compared to using only well log measurements for the estimation. The amount of benefit depends primarily on the strength of the petrophysical relation between the GPR and porosity data, the variability of this relation throughout the investigated site, and lateral structural continuity at the site.

  20. Clinical Utility of Sequential Minimal Residual Disease Measurements in the Context of Risk-based Therapy in Childhood Acute Lymphoblastic Leukemia: a Prospective Study

    PubMed Central

    Pui, Ching-Hon; Pei, Deqing; Coustan-Smith, Elaine; Jeha, Sima; Cheng, Cheng; Bowman, W Paul; Sandlund, John T; Ribeiro, Raul C; Rubnitz, Jeffrey E; Inaba, Hiroto; Bhojwani, Deepa; Gruber, Tanja A; Leung, Wing H; Downing, James R; Evans, William E; Relling, Mary V; Campana, Dario

    2015-01-01

    Summary Background The level of minimal residual disease (MRD) during remission induction is the most important prognostic indicator in acute lymphoblastic leukemia (ALL). We determined the clinical significance of MRD in the context of a prospective clinical study in which sequential MRD measurements were used to guide treatment decisions. Methods Between 2000 and 2007, 498 evaluable patients with newly diagnosed ALL were enrolled in St. Jude Study XV. Risk of relapse was provisionally classified as low, standard or high according to presenting clinical and laboratory features. Final risk assignment to determine treatment intensity was based mainly on MRD levels measured on days 19 and 46 of remission induction, and on week 7 of continuation treatment. Additional MRD determinations were made on weeks 17, 48 and 120 (end of therapy). Findings Regardless of the provisional risk classification, 10-year event-free survival was significantly inferior for patients with MRD ≥1% on day 19 compared with that of patients having lower MRD levels: 69.2% (95% CI 49.6–82.4, n=36) versus 95.5% (91.7–97.5, n=244) (p<0.001) for the provisional low-risk group and 65.1% (50.7–76.2, n=56) versus 82.9% (75.6–88.2, n=142) (p=0.008) for the provisional standard-risk group. Twelve patients with provisional low-risk ALL and MRD ≥1% on day 19 but negative MRD (<0.01%) on day 46 were treated for standard-risk ALL and had a 10-year event-free survival of 88.9% (43.3–98.4). For the 244 provisional low-risk patients, an MRD level of <1% on day 19 predicted a superior outcome, regardless of the MRD level on day 46. Among provisional standard-risk patients with MRD <1% on day 19, the 15 with persistent MRD on day 46 tended to have an inferior 10-year event-free survival compared with the 126 lacking detectable MRD (72.7% [42.5–88.8] versus 84.0% [76.3–89.4], p=0.06) after receiving the same post-remission treatment for standard-risk ALL. Among patients attaining MRD

  1. Optimal sequential Bayesian analysis for degradation tests.

    PubMed

    Rodríguez-Narciso, Silvia; Christen, J Andrés

    2016-07-01

    Degradation tests are especially difficult to conduct for items with high reliability. Test costs, caused mainly by prolonged item duration and item destruction costs, establish the necessity of sequential degradation test designs. We propose a methodology that sequentially selects the optimal observation times to measure the degradation, using a convenient rule that maximizes the inference precision and minimizes test costs. In particular our objective is to estimate a quantile of the time to failure distribution, where the degradation process is modelled as a linear model using Bayesian inference. The proposed sequential analysis is based on an index that measures the expected discrepancy between the estimated quantile and its corresponding prediction, using Monte Carlo methods. The procedure was successfully implemented for simulated and real data. PMID:26307336

  2. Multi-scale structural and chemical analysis of sugarcane bagasse in the process of sequential acid–base pretreatment and ethanol production by Scheffersomyces shehatae and Saccharomyces cerevisiae

    PubMed Central

    2014-01-01

    Background Heavy usage of gasoline, burgeoning fuel prices, and environmental issues have paved the way for the exploration of cellulosic ethanol. Cellulosic ethanol production technologies are emerging and require continued technological advancements. One of the most challenging issues is the pretreatment of lignocellulosic biomass for the desired sugars yields after enzymatic hydrolysis. We hypothesized that consecutive dilute sulfuric acid-dilute sodium hydroxide pretreatment would overcome the native recalcitrance of sugarcane bagasse (SB) by enhancing cellulase accessibility of the embedded cellulosic microfibrils. Results SB hemicellulosic hydrolysate after concentration by vacuum evaporation and detoxification showed 30.89 g/l xylose along with other products (0.32 g/l glucose, 2.31 g/l arabinose, and 1.26 g/l acetic acid). The recovered cellulignin was subsequently delignified by sodium hydroxide mediated pretreatment. The acid–base pretreated material released 48.50 g/l total reducing sugars (0.91 g sugars/g cellulose amount in SB) after enzymatic hydrolysis. Ultra-structural mapping of acid–base pretreated and enzyme hydrolyzed SB by microscopic analysis (scanning electron microcopy (SEM), transmitted light microscopy (TLM), and spectroscopic analysis (X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy) elucidated the molecular changes in hemicellulose, cellulose, and lignin components of bagasse. The detoxified hemicellulosic hydrolysate was fermented by Scheffersomyces shehatae (syn. Candida shehatae UFMG HM 52.2) and resulted in 9.11 g/l ethanol production (yield 0.38 g/g) after 48 hours of fermentation. Enzymatic hydrolysate when fermented by Saccharomyces cerevisiae 174 revealed 8.13 g/l ethanol (yield 0.22 g/g) after 72 hours of fermentation. Conclusions Multi-scale structural studies of SB after sequential acid–base

  3. Laser-Based Slam with Efficient Occupancy Likelihood Map Learning for Dynamic Indoor Scenes

    NASA Astrophysics Data System (ADS)

    Li, Li; Yao, Jian; Xie, Renping; Tu, Jinge; Feng, Chen

    2016-06-01

    Location-Based Services (LBS) have attracted growing attention in recent years, especially in indoor environments. The fundamental technique of LBS is the map building for unknown environments, this technique also named as simultaneous localization and mapping (SLAM) in robotic society. In this paper, we propose a novel approach for SLAMin dynamic indoor scenes based on a 2D laser scanner mounted on a mobile Unmanned Ground Vehicle (UGV) with the help of the grid-based occupancy likelihood map. Instead of applying scan matching in two adjacent scans, we propose to match current scan with the occupancy likelihood map learned from all previous scans in multiple scales to avoid the accumulation of matching errors. Due to that the acquisition of the points in a scan is sequential but not simultaneous, there unavoidably exists the scan distortion at different extents. To compensate the scan distortion caused by the motion of the UGV, we propose to integrate a velocity of a laser range finder (LRF) into the scan matching optimization framework. Besides, to reduce the effect of dynamic objects such as walking pedestrians often existed in indoor scenes as much as possible, we propose a new occupancy likelihood map learning strategy by increasing or decreasing the probability of each occupancy grid after each scan matching. Experimental results in several challenged indoor scenes demonstrate that our proposed approach is capable of providing high-precision SLAM results.

  4. Adaptive sequential testing for multiple comparisons.

    PubMed

    Gao, Ping; Liu, Lingyun; Mehta, Cyrus

    2014-01-01

    We propose a Markov process theory-based adaptive sequential testing procedure for multiple comparisons. The procedure can be used for confirmative trials involving multi-comparisons, including dose selection or population enrichment. Dose or subpopulation selection and sample size modification can be made at any interim analysis. Type I error control is exact. PMID:24926848

  5. Terminating Sequential Delphi Survey Data Collection

    ERIC Educational Resources Information Center

    Kalaian, Sema A.; Kasim, Rafa M.

    2012-01-01

    The Delphi survey technique is an iterative mail or electronic (e-mail or web-based) survey method used to obtain agreement or consensus among a group of experts in a specific field on a particular issue through a well-designed and systematic multiple sequential rounds of survey administrations. Each of the multiple rounds of the Delphi survey…

  6. Lag Sequential Analysis: Taking Consultation Communication Research to the Movies.

    ERIC Educational Resources Information Center

    Benes, Kathryn M.; Gutkin, Terry B.; Kramer, Jack J.

    1995-01-01

    Describes lag-sequential analysis and its unique contributions to research literature, addressing communication processes in school-based consultation. For purposes of demonstrating the application and potential utility of lag-sequential analysis, article analyzes the communication behaviors of two consultants. Considers directions for future…

  7. A sequential decision-theoretic model for medical diagnostic system.

    PubMed

    Li, Aiping; Jin, Songchang; Zhang, Lumin; Jia, Yan

    2015-01-01

    Although diagnostic expert systems using a knowledge base which models decision-making of traditional experts can provide important information to non-experts, they tend to duplicate the errors made by experts. Decision-Theoretic Model (DTM) is therefore very useful in expert system since they prevent experts from incorrect reasoning under uncertainty. For the diagnostic expert system, corresponding DTM and arithmetic are studied and a sequential diagnostic decision-theoretic model based on Bayesian Network is given. In the model, the alternative features are categorized into two classes (including diseases features and test features), then an arithmetic for prior of test is provided. The different features affect other features weights are also discussed. Bayesian Network is adopted to solve uncertainty presentation and propagation. The model can help knowledge engineers model the knowledge involved in sequential diagnosis and decide evidence alternative priority. A practical example of the models is also presented: at any time of the diagnostic process the expert is provided with a dynamically updated list of suggested tests in order to support him in the decision-making problem about which test to execute next. The results show it is better than the traditional diagnostic model which is based on experience. PMID:26410326

  8. The structure of sequential effects.

    PubMed

    Gökaydin, Dinis; Navarro, Daniel J; Ma-Wyatt, Anna; Perfors, Amy

    2016-01-01

    There is a long history of research into sequential effects, extending more than one hundred years. The pattern of sequential effects varies widely with both experimental conditions as well as for different individuals performing the same experiment. Yet this great diversity of results is poorly understood, particularly with respect to individual variation, which save for some passing mentions has largely gone unreported in the literature. Here we seek to understand the way in which sequential effects vary by identifying the causes underlying the differences observed in sequential effects. In order to achieve this goal we perform principal component analysis on a dataset of 158 individual results from participants performing different experiments with the aim of identifying hidden variables responsible for sequential effects. We find a latent structure consisting of 3 components related to sequential effects-2 main and 1 minor. A relationship between the 2 main components and the separate processing of stimuli and of responses is proposed on the basis of previous empirical evidence. It is further speculated that the minor component of sequential effects arises as the consequence of processing delays. Independently of the explanation for the latent variables encountered, this work provides a unified descriptive model for a wide range of different types of sequential effects previously identified in the literature. In addition to explaining individual differences themselves, it is demonstrated how the latent structure uncovered here is useful in understanding the classical problem of the dependence of sequential effects on the interval between successive stimuli. PMID:26523425

  9. [The possibilities for determining the passenger position inside the car passenger compartment based on the injuries to the extremities estimated with the use of the sequential mathematical analysis].

    PubMed

    Smirenin, S A; Khabova, Z S; Fetisov, V A

    2015-01-01

    The objective of the present study was to determine the diagnostic coefficients (DC) of injuries to the upper and lower extremities of the passengers inside the car passenger compartment based on the analysis of 599 archival expert documents available from 45 regional state bureaus of forensic medical examination of the Russian federation for the period from 1995 till 2014. These materials included the data obtained by the examination of 200 corpses and 300 live persons involved in the traffic accidents. The statistical and mathematical treatment of these materials with the use the sequential analysis method based on the Byes and Wald formulas yielded the diagnostic coefficients that made it possible to identify the most important signs characterizing the risk of injuries for the passenger occupying the front seat of the vehicle. In the case of the lethal outcome, such injuries include fractures of the right femur (DC -8.9), bleeding (DC -7.1), wounds in the soft tissues of the right thigh (DC -5.0) with the injurious force applied to its anterior surface, bruises on the posterior surface of the right shoulder (DC -6.2), the right deltoid region (DC -5.9), and the posterior surface of the right forearm (DC -5.5), fractures of the right humerus (DC -5.), etc. When both the driver and the passengers survive, the most informative signs in the latter are bleeding and scratches (DC -14.5 and 11.5 respectively) in the soft tissues at the posterior surface of the right shoulder, fractures of the right humerus (DC -10.0), bruises on the anterior surface of the right thigh (DC -13.0), the posterior surface of the right forearm (DC -10.0) and the fontal region of the right lower leg (DC -10.0), bleeding in the posterior region of the right forearm (DC -9.0) and the anterior region of the left thigh (DC -8.6), fractures of the right femur (DG -8.1), etc. It is concluded that the knowledge of diagnostic coefficients helps to draw attention of the experts to the analysis of the

  10. Sequentially Executed Model Evaluation Framework

    SciTech Connect

    2015-10-20

    Provides a message passing framework between generic input, model and output drivers, and specifies an API for developing such drivers. Also provides batch and real-time controllers which step the model and I/O through the time domain (or other discrete domain), and sample I/O drivers. This is a library framework, and does not, itself, solve any problems or execute any modeling. The SeMe framework aids in development of models which operate on sequential information, such as time-series, where evaluation is based on prior results combined with new data for this iteration. Has applications in quality monitoring, and was developed as part of the CANARY-EDS software, where real-time water quality data is being analyzed for anomalies.

  11. Sequentially Executed Model Evaluation Framework

    SciTech Connect

    2014-02-14

    Provides a message passing framework between generic input, model and output drivers, and specifies an API for developing such drivers. Also provides batch and real-time controllers which step the model and 1/0 through the time domain (or other discrete domain), and sample 1/0 drivers. This is a Framework library framework, and does not, itself, solve any problems or execute any modelling. The SeMe framework aids in development of models which operate on sequential information, such as time-series, where evaluation is based on prior results combined with new data for this iteration. Ha) applications in quality monitoring, and was developed as part of the CANARY-EDS software, where real-time water quality data is being analyzed

  12. Sequentially Executed Model Evaluation Framework

    Energy Science and Technology Software Center (ESTSC)

    2014-02-14

    Provides a message passing framework between generic input, model and output drivers, and specifies an API for developing such drivers. Also provides batch and real-time controllers which step the model and 1/0 through the time domain (or other discrete domain), and sample 1/0 drivers. This is a Framework library framework, and does not, itself, solve any problems or execute any modelling. The SeMe framework aids in development of models which operate on sequential information, suchmore » as time-series, where evaluation is based on prior results combined with new data for this iteration. Ha) applications in quality monitoring, and was developed as part of the CANARY-EDS software, where real-time water quality data is being analyzed« less

  13. Sequentially Executed Model Evaluation Framework

    Energy Science and Technology Software Center (ESTSC)

    2015-10-20

    Provides a message passing framework between generic input, model and output drivers, and specifies an API for developing such drivers. Also provides batch and real-time controllers which step the model and I/O through the time domain (or other discrete domain), and sample I/O drivers. This is a library framework, and does not, itself, solve any problems or execute any modeling. The SeMe framework aids in development of models which operate on sequential information, such asmore » time-series, where evaluation is based on prior results combined with new data for this iteration. Has applications in quality monitoring, and was developed as part of the CANARY-EDS software, where real-time water quality data is being analyzed for anomalies.« less

  14. A quantum mechanics-based approach to model incident-induced dynamic driver behavior

    NASA Astrophysics Data System (ADS)

    Sheu, Jiuh-Biing

    2008-08-01

    A better understanding of the psychological factors influencing drivers, and the resulting driving behavior responding to incident-induced lane traffic phenomena while passing by an incident site is vital to the improvement of road safety. This paper presents a microscopic driver behavior model to explain the dynamics of the instantaneous driver decision process under lane-blocking incidents on adjacent lanes. The proposed conceptual framework decomposes the corresponding driver decision process into three sequential phases: (1) initial stimulus, (2) glancing-around car-following, and (3) incident-induced driving behavior. The theorem of quantum mechanics in optical flows is applied in the first phase to explain the motion-related perceptual phenomena while vehicles approach the incident site in adjacent lanes, followed by the incorporation of the effect of quantum optical flows in modeling the induced glancing-around car-following behavior in the second phase. Then, an incident-induced driving behavior model is formulated to reproduce the dynamics of driver behavior conducted in the process of passing by an incident site in the adjacent lanes. Numerical results of model tests using video-based incident data indicate the validity of the proposed traffic behavior model in analyzing the incident-induced lane traffic phenomena. It is also expected that such a proposed quantum-mechanics based methodology can throw more light if applied to driver psychology and response in anomalous traffic environments in order to improve road safety.

  15. A Web-Based Peer-Modeling Intervention Aimed at Lifestyle Changes in Patients With Coronary Heart Disease and Chronic Back Pain: Sequential Controlled Trial

    PubMed Central

    Romppel, Matthias; Richter, Cynthia; Hoberg, Eike; Hahmann, Harry; Scherwinski, Inge; Kosmützky, Gregor; Grande, Gesine

    2014-01-01

    Background Traditional secondary prevention programs often fail to produce sustainable behavioral changes in everyday life. Peer-modeling interventions and integration of peer experiences in health education are a promising way to improve long-term effects in behavior modification. However, effects of peer support modeling on behavioral change have not been evaluated yet. Therefore, we implemented and evaluated a website featuring patient narratives about successful lifestyle changes. Objective Our aim is to examine the effects of using Web-based patient narratives about successful lifestyle change on improvements in physical activity and eating behavior for patients with coronary heart disease and chronic back pain 3 months after participation in a rehabilitation program. Methods The lebensstil-aendern (“lifestyle-change”) website is a nonrestricted, no-cost, German language website that provides more than 1000 video, audio, and text clips from interviews with people with coronary heart disease and chronic back pain. To test efficacy, we conducted a sequential controlled trial and recruited patients with coronary heart disease and chronic back pain from 7 inpatient rehabilitation centers in Germany. The intervention group attended a presentation on the website; the control group did not. Physical activity and eating behavior were assessed by questionnaire during the rehabilitation program and 12 weeks later. Analyses were conducted based on an intention-to-treat and an as-treated protocol. Results A total of 699 patients were enrolled and 571 cases were included in the analyses (control: n=313, intervention: n=258; female: 51.1%, 292/571; age: mean 53.2, SD 8.6 years; chronic back pain: 62.5%, 357/571). Website usage in the intervention group was 46.1% (119/258). In total, 141 trial participants used the website. Independent t tests based on the intention-to-treat protocol only demonstrated nonsignificant trends in behavioral change related to physical

  16. One-pot synthesis of 1H-isochromenes and 1,2-dihydroisoquinolines by a sequential isocyanide-based multicomponent/Wittig reaction.

    PubMed

    Wang, Long; Guan, Zhi-Rong; Ding, Ming-Wu

    2016-02-28

    A one-pot synthesis of 1H-isochromenes and 1,2-dihydroisoquinolines by a I-MCR/Wittig sequence was developed. The reaction of phosphonium salt , an acid, an amine (or without), and an isocyanide gave the 1H-isochromenes or 1,2-dihydroisoquinolines in good yields by a sequential Passerini or Ugi condensation and an intramolecular Wittig reaction in the presence of K2CO3. PMID:26810599

  17. Discrete filtering techniques applied to sequential GPS range measurements

    NASA Technical Reports Server (NTRS)

    Vangraas, Frank

    1987-01-01

    The basic navigation solution is described for position and velocity based on range and delta range (Doppler) measurements from NAVSTAR Global Positioning System satellites. The application of discrete filtering techniques is examined to reduce the white noise distortions on the sequential range measurements. A second order (position and velocity states) Kalman filter is implemented to obtain smoothed estimates of range by filtering the dynamics of the signal from each satellite separately. Test results using a simulated GPS receiver show a steady-state noise reduction, the input noise variance divided by the output noise variance, of a factor of four. Recommendations for further noise reduction based on higher order Kalman filters or additional delta range measurements are included.

  18. Multi-Attribute Sequential Search

    ERIC Educational Resources Information Center

    Bearden, J. Neil; Connolly, Terry

    2007-01-01

    This article describes empirical and theoretical results from two multi-attribute sequential search tasks. In both tasks, the DM sequentially encounters options described by two attributes and must pay to learn the values of the attributes. In the "continuous" version of the task the DM learns the precise numerical value of an attribute when she…

  19. Student Storytelling through Sequential Art

    ERIC Educational Resources Information Center

    Fay, David

    2007-01-01

    If you are interested in using sequential art forms such as comic books in your EFL classroom, this article is full of helpful advice. Reading sequential art is beneficial because students can work with authentic texts with real language and graphic support. Students can also apply research and cultural knowledge to the creation of their own…

  20. Giant intracranial aneurysms: rapid sequential computed tomography

    SciTech Connect

    Pinto, R.S.; Cohen, W.A.; Kricheff, I.I.; Redington, R.W.; Berninger, W.H.

    1982-11-01

    Giant intracranial aneurysms often present as mass lesions rather than with subarachnoid hemorrhage. Routine computed tomographic (CT) scans with contrast material will generally detect them, but erroneous diagnosis of basal meningioma is possible. Rapid sequential scanning (dynamic CT) after bolus injection of 40 ml of Renografin-76 can conclusively demonstrate an intracranial aneurysm, differentiating it from other lesions by transit-time analysis of the passage of contrast medium. In five patients, the dynamics of contrast bolus transit in aneurysms were consistently different from the dynamics in pituitary tumors, craniopharyngiomas, and meningiomas, thereby allowing a specific diagnosis. Dynamic CT was also useful after treatment of the aneurysms by carotid artery ligation and may be used as an alternative to angiographic evaluation in determining luminal patency or thrombosis.

  1. Sparse decomposition learning based dynamic MRI reconstruction

    NASA Astrophysics Data System (ADS)

    Zhu, Peifei; Zhang, Qieshi; Kamata, Sei-ichiro

    2015-02-01

    Dynamic MRI is widely used for many clinical exams but slow data acquisition becomes a serious problem. The application of Compressed Sensing (CS) demonstrated great potential to increase imaging speed. However, the performance of CS is largely depending on the sparsity of image sequence in the transform domain, where there are still a lot to be improved. In this work, the sparsity is exploited by proposed Sparse Decomposition Learning (SDL) algorithm, which is a combination of low-rank plus sparsity and Blind Compressed Sensing (BCS). With this decomposition, only sparsity component is modeled as a sparse linear combination of temporal basis functions. This enables coefficients to be sparser and remain more details of dynamic components comparing learning the whole images. A reconstruction is performed on the undersampled data where joint multicoil data consistency is enforced by combing Parallel Imaging (PI). The experimental results show the proposed methods decrease about 15~20% of Mean Square Error (MSE) compared to other existing methods.

  2. Eradication of Ebola Based on Dynamic Programming.

    PubMed

    Zhu, Jia-Ming; Wang, Lu; Liu, Jia-Bao

    2016-01-01

    This paper mainly studies the eradication of the Ebola virus, proposing a scientific system, including three modules for the eradication of Ebola virus. Firstly, we build a basic model combined with nonlinear incidence rate and maximum treatment capacity. Secondly, we use the dynamic programming method and the Dijkstra Algorithm to set up M-S (storage) and several delivery locations in West Africa. Finally, we apply the previous results to calculate the total cost, production cost, storage cost, and shortage cost. PMID:27313655

  3. Eradication of Ebola Based on Dynamic Programming

    PubMed Central

    Zhu, Jia-Ming; Wang, Lu; Liu, Jia-Bao

    2016-01-01

    This paper mainly studies the eradication of the Ebola virus, proposing a scientific system, including three modules for the eradication of Ebola virus. Firstly, we build a basic model combined with nonlinear incidence rate and maximum treatment capacity. Secondly, we use the dynamic programming method and the Dijkstra Algorithm to set up M-S (storage) and several delivery locations in West Africa. Finally, we apply the previous results to calculate the total cost, production cost, storage cost, and shortage cost. PMID:27313655

  4. A Blackboard-Based Dynamic Instructional Planner. ONR Final Report.

    ERIC Educational Resources Information Center

    Murray, William R.

    Dynamic instructional planning was explored as a control mechanism for intelligent tutoring systems through the development of the Blackboard Instructional Planner--a blackboard software-based dynamic planner for computerized intelligent tutoring systems. The planner, designed to be generic to tutors teaching troubleshooting for complex physical…

  5. The Effect of Dynamic Assessment Based Instruction on Children's Learning

    ERIC Educational Resources Information Center

    Baek, Sun-Geun; Kim, Kyoung Jin

    2003-01-01

    The purpose of this study is to demonstrate that dynamic assessment based instruction increases children's learning by using a quasi-experimental research design in Korea. In this study, dynamic assessment is defined as a measurement method of the zone of proximal development (ZPD) as well as the qualitative and quantitative diagnostic information…

  6. A Dynamic Usage Based Perspective on L2 Writing

    ERIC Educational Resources Information Center

    Verspoor, Marjolijn; Schmid, Monika S.; Xu, Xiaoyan

    2012-01-01

    The goal of this study was to explore the contribution that a dynamic usage based (DUB) perspective can bring to the establishment of objective measures to assess L2 learners' written texts and at the same time to gain insight into the dynamic process of language development. Four hundred and thirty seven texts written by Dutch learners of English…

  7. Continuity of the sequential product of sequential quantum effect algebras

    NASA Astrophysics Data System (ADS)

    Lei, Qiang; Su, Xiaochao; Wu, Junde

    2016-04-01

    In order to study quantum measurement theory, sequential product defined by A∘B = A1/2BA1/2 for any two quantum effects A, B has been introduced. Physically motivated conditions ask the sequential product to be continuous with respect to the strong operator topology. In this paper, we study the continuity problems of the sequential product A∘B = A1/2BA1/2 with respect to other important topologies, such as norm topology, weak operator topology, order topology, and interval topology.

  8. Adaptive sequential controller

    DOEpatents

    El-Sharkawi, Mohamed A.; Xing, Jian; Butler, Nicholas G.; Rodriguez, Alonso

    1994-01-01

    An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

  9. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    SciTech Connect

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  10. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    PubMed Central

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  11. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser.

    PubMed

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  12. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  13. A Jini-based dynamic service WebGIS model

    NASA Astrophysics Data System (ADS)

    Xuan, Wenling; Chen, Xiuwan; Huang, Zhaoqiang; Zhao, Gang

    2007-06-01

    The development of current GIS technology has evolved from single platform GIS system into WebGIS. However, The Geographic Information Services (GIServices) provision and application manner cannot meet the requirement of pervasive computing environment. Jini/JAVA technique, a dynamic distributed architecture for providing spontaneous network of services, might be a tool/solution to improve the GIService performance of current WebGIS. This paper studies and analyses Jini infrastructure and its dynamic service mechanism, designs a new WebGIS architecture with Jini-based dynamic service model. The experiment shows that Jini technique can be integrated into WebGIS and to realize the dynamic services organization and management.

  14. NRC PAGE. Sequential Analysis Materials Balance

    SciTech Connect

    Picard, R.

    1992-01-13

    NRCPAGE is used in safeguards applications to detect a recurring loss of special nuclear material by frequent evaluation (sequential analysis) of accountability data. Standard sequential testing procedures are traditionally based on sequences of independent and normally distributed measurements. This same approach can be applied to materials balance (MB) data. Here, the term materials balance has a meaning similar to inventory difference and represents a materials loss indicator localized in time and space. However, distinct MBs cannot be reasonably treated as statistically independent and may not always be reasonably treated as normally distributed. Furthermore, the covariance structure associated with a given MB sequence is not known and must be estimated. Nonindependence is treated by converting the MB sequence to the innovation sequence, sometimes called the ITMUF sequence or the sequence of MUF residuals, which are statistically independent and amenable to sequential test procedures. A one-sided page`s test, effective for a wide range of recurring loss scenarios, is applied to the standardized innovation sequence. The program can be easily modified to suit particular needs; the models for the assumption of multivariate normality for MBs when computing the innovation sequence or the test procedure can be changed as can the input/output format, dimensioning, local error checking, and simulation work. Input files can be sequentially constructed using local text editors to update existing files. Output files can be read by graphics, report writer, or other stand-alone utility routines.

  15. Dynamic Culture Conditions to Generate Silk-Based Tissue-Engineered Vascular Grafts

    PubMed Central

    Zhang, Xiaohui; Wang, Xiuli; Keshav, Vinny; Wang, Xiaoqin; Johanas, Jacqueline; Leisk, Gary; Kaplan, David L

    2009-01-01

    Tissue engineering is an alternative approach for the preparation of small-diameter (<6 mm) vascular grafts due to the potential to control thrombosis, anastomotic cellular hyperplasia and matrix production. This control also requires the maintenance of graft patency in vivo, appropriate mechanical properties and the formation of a functional endothelium. As a first step in generating such tissue-engineered vascular grafts (TEVG), our objective was to develop a tissue-engineered construct that mimicked the structure of blood vessels using tubular electrospun silk fibroin scaffolds (ESFS) with suitable mechanical properties. Human coronary artery smooth muscle cells (HCASMCs) and human aortic endothelial cells (HAECs) were sequentially seeded onto the luminal surface of the tubular scaffolds and cultivated under physiological pulsatile flow. The results demonstrated that TEVGs under dynamic flow conditions had better outcome than static culture controls in terms of cell proliferation and alignment, ECM production and cell phenotype based on transcript and protein level assessments. The metabolic activity of HCASMCs present in the TEGs indicated the advantage of dynamic flow over static culture in effective nutrient and oxygen distribution to the cells. A matrigel coating as a basement membrane mimic for ECM significantly improved endothelium coverage and retention under physiological shear forces. The results demonstrate the successful integration of vascular cells into silk electrospun tubular scaffolds as a step toward the development of a TEVG similar to native vessels in terms of vascular cell outcomes and mechanical properties. PMID:19232717

  16. Robust dynamical recurrences based on Floquet spectrum

    NASA Astrophysics Data System (ADS)

    Ayub, M.; Naseer, K.; Saif, F.

    2011-10-01

    Robust recurrence behavior of wave packets in periodically driven systems and coupled higher dimensional systems is analyzed, which takes place in the realm of higher coupling/modulation strength. We analyze the wave packet dynamics close to nonlinear resonances developed in the systems and provide the analytical understanding of recurrence times. We apply these analytical results to investigate the recurrence times of matter waves in optical lattice in the presence of external periodic forcing. The obtained analytical results can experimentally be observed using currently available experimental setups.

  17. Model based control of dynamic atomic force microscope

    SciTech Connect

    Lee, Chibum; Salapaka, Srinivasa M.

    2015-04-15

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H{sub ∞} control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments.

  18. Model based control of dynamic atomic force microscope.

    PubMed

    Lee, Chibum; Salapaka, Srinivasa M

    2015-04-01

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H(∞) control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments. PMID:25933864

  19. Dynamic based damage detection in composite structures

    NASA Astrophysics Data System (ADS)

    Banerjee, Sauvik; Ricci, Fabrizio; Baid, Harsh; Mal, Ajit K.

    2009-03-01

    Advanced composites are being used increasingly in state-of-the-art aircraft and aerospace structures. In spite of their many advantages, composite materials are highly susceptible to hidden flaws that may occur at any time during the life cycle of a structure, and if undetected, may cause sudden and catastrophic failure of the entire structure. This paper is concerned with the detection and characterization of hidden defects in composite structures before they grow to a critical size. A methodology for automatic damage identification and localization is developed using a combination of vibration and wave propagation data. The structure is assumed to be instrumented with an array of actuators and sensors to excite and record its dynamic response, including vibration and wave propagation effects. A damage index, calculated from the measured dynamical response of the structure in a previous (reference) state and the current state, is introduced as a determinant of structural damage. The indices are used to identify low velocity impact damages in increasingly complex composite structural components. The potential application of the approach in developing health monitoring systems in defects-critical structures is indicated.

  20. Dynamic Inversion based Control of a Docking Mechanism

    NASA Technical Reports Server (NTRS)

    Kulkarni, Nilesh V.; Ippolito, Corey; Krishnakumar, Kalmanje

    2006-01-01

    The problem of position and attitude control of the Stewart platform based docking mechanism is considered motivated by its future application in space missions requiring the autonomous docking capability. The control design is initiated based on the framework of the intelligent flight control architecture being developed at NASA Ames Research Center. In this paper, the baseline position and attitude control system is designed using dynamic inversion with proportional-integral augmentation. The inverse dynamics uses a Newton-Euler formulation that includes the platform dynamics, the dynamics of the individual legs along with viscous friction in the joints. Simulation results are presented using forward dynamics simulated by a commercial physics engine that builds the system as individual elements with appropriate joints and uses constrained numerical integration,

  1. Feasibility of atomic layer etching of polymer material based on sequential O{sub 2} exposure and Ar low-pressure plasma-etching

    SciTech Connect

    Vogli, Evelina; Metzler, Dominik; Oehrlein, Gottlieb S.

    2013-06-24

    We describe controlled, self-limited etching of a polystyrene polymer using a composite etching cycle consisting of sequential deposition of a thin reactive layer from precursors produced from a polymer-coated electrode within the etching chamber, modification using O{sub 2} exposure, and subsequent low-pressure Ar plasma etching, which removes the oxygen-modified deposited reactive layer along with Almost-Equal-To 0.1 nm unmodified polymer. Deposition prevents net etching of the unmodified polymer during the etching step and enables self-limited etch rates of 0.1 nm/cycle.

  2. Implementation of Temperature Sequential Controller on Variable Speed Drive

    NASA Astrophysics Data System (ADS)

    Cheong, Z. X.; Barsoum, N. N.

    2008-10-01

    There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

  3. Silver-mediated base pairings: towards dynamic DNA nanostructures with enhanced chemical and thermal stability

    NASA Astrophysics Data System (ADS)

    Swasey, Steven M.; Gwinn, Elisabeth G.

    2016-04-01

    The thermal and chemical fragility of DNA nanomaterials assembled by Watson–Crick (WC) pairing constrain the settings in which these materials can be used and how they can be functionalized. Here we investigate use of the silver cation, Ag+, as an agent for more robust, metal-mediated self-assembly, focusing on the simplest duplex building blocks that would be required for more elaborate Ag+–DNA nanostructures. Our studies of Ag+-induced assembly of non-complementary DNA oligomers employ strands of 2–24 bases, with varied base compositions, and use electrospray ionization mass spectrometry to determine product compositions. High yields of duplex products containing narrowly distributed numbers of Ag+ can be achieved by optimizing solution conditions. These Ag+-mediated duplexes are stable to at least 60 mM Mg2+, higher than is necessary for WC nanotechnology schemes such as tile assemblies and DNA origami, indicating that sequential stages of Ag+-mediated and WC-mediated assembly may be feasible. Circular dichroism spectroscopy suggests simple helical structures for Ag+-mediated duplexes with lengths to at least 20 base pairs, and further indicates that the structure of cytosine-rich duplexes is preserved at high urea concentrations. We therefore propose an approach towards dynamic DNA nanomaterials with enhanced thermal and chemical stability through designs that combine sturdy silver-mediated ‘frames’ with WC paired ‘pictures’.

  4. Coherent versus incoherent sequential quantum measurements

    SciTech Connect

    Filip, Radim

    2011-03-15

    We compare a trade-off between knowledge and decoherence for the incoherent and coherent partial sequential compatible measurements on single-qubit systems. The individual partial measurement nondestructively monitors basis states of the system by single-qubit meter. For the same decoherence caused by this unbiased measurement, the individual coherent measurement gives more knowledge than the incoherent one. For identical sequential coherent measurements, knowledge accumulated not additively increases more slowly than for the incoherent measurements. The overall knowledge can be accumulated using an adaptive measurement strategy on the meters if the single-qubit coherence of meters is kept. On the other hand, preservation of the mutual qubit coherence between the meters necessary for the collective measurement strategy is not required. A loss of single-qubit coherence degrades the coherent measurements back to the incoherent ones. Since the decoherence caused by the measurement process is a quadratic function of knowledge extracted by the individual measurement, Zeno-like behavior can be observed for repetitive weak compatible measurements. This unconditional universal effect does not depend on any dynamics of the qubit and it is a direct consequence of optimally controlled sequential evolution of quantum information.

  5. Dynamic projecting IR zoom-based systems

    NASA Astrophysics Data System (ADS)

    Sturlesi, Benjamin E.; Mangoubi, Samuel; Ben-David, Emanuel

    1995-09-01

    An IR target simulating projector system may sometimes require zooming lenses to simulate continuously the target's increasing size as a missile closes the range. In addition, special opto-mechanical layouts may sometimes be needed to allow cascaded action of two or more zooms to increase the zooming range, or to present the missile simultaneously two or more spectral regions. The zooms in these systems may differ in some important characteristics from the more conventional types: (1) The maximum speed and acceleration of their moving parts, as required by the dynamics of the missile-target approach scenario, are to be limited by the performance of commercially available stages carrying those parts, and (2) the motion control system must assure strict adherence to the 'zoom function' (relative position of the zoom's moving parts) to avoid defocusing during the zooming phase. In this paper we describe the implications of complying with these requirements on implementations actually designed and executed.

  6. Modeling of a Sequential Two-Stage Combustor, Supplement

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Liu, N.-S.; Gallagher, J. R.; Ryder, R. C.; Brankovic, A.; Hendricks, J. A.

    2005-01-01

    A sequential two-stage, natural gas fueled power generation combustion system is modeled to examine the fundamental aerodynamic and combustion characteristics of the system. The modeling methodology includes CAD-based geometry definition, and combustion computational fluid dynamics analysis. Graphical analysis is used to examine the complex vortical patterns in each component, identifying sources of pressure loss. The simulations demonstrate the importance of including the rotating high-pressure turbine blades in the computation, as this results in direct computation of combustion within the first turbine stage, and accurate simulation of the flow in the second combustion stage. The direct computation of hot-streaks through the rotating high-pressure turbine stage leads to improved understanding of the aerodynamic relationships between the primary and secondary combustors and the turbomachinery.

  7. Modeling of a Sequential Two-Stage Combustor

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Liu, N.-S.; Gallagher, J. R.; Ryder, R. C.; Brankovic, A.; Hendricks, J. A.

    2005-01-01

    A sequential two-stage, natural gas fueled power generation combustion system is modeled to examine the fundamental aerodynamic and combustion characteristics of the system. The modeling methodology includes CAD-based geometry definition, and combustion computational fluid dynamics analysis. Graphical analysis is used to examine the complex vortical patterns in each component, identifying sources of pressure loss. The simulations demonstrate the importance of including the rotating high-pressure turbine blades in the computation, as this results in direct computation of combustion within the first turbine stage, and accurate simulation of the flow in the second combustion stage. The direct computation of hot-streaks through the rotating high-pressure turbine stage leads to improved understanding of the aerodynamic relationships between the primary and secondary combustors and the turbomachinery.

  8. Dynamics of plant DNA replication based on PCNA visualization.

    PubMed

    Yokoyama, Ryohei; Hirakawa, Takeshi; Hayashi, Seri; Sakamoto, Takuya; Matsunaga, Sachihiro

    2016-01-01

    DNA replication is an essential process for the copying of genomic information in living organisms. Imaging of DNA replication in tissues and organs is mainly performed using fixed cells after incorporation of thymidine analogs. To establish a useful marker line to measure the duration of DNA replication and analyze the dynamics of DNA replication, we focused on the proliferating cell nuclear antigen (PCNA), which functions as a DNA sliding clamp for replicative DNA polymerases and is an essential component of replisomes. In this study we produced an Arabidopsis thaliana line expressing PCNA1 fused with the green fluorescent protein under the control of its own promoter (pAtPCNA1::AtPCNA1-EGFP). The duration of the S phase measured using the expression line was consistent with that measured after incorporation of a thymidine analog. Live cell imaging revealed that three distinct nuclear localization patterns (whole, dotted, and speckled) were sequentially observable. These whole, dotted, and speckled patterns of subnuclear AtPCNA1 signals were indicative of the G1 or G2 phase, early S phase and late S phase, respectively. The results indicate that the pAtPCNA1::AtPCNA1-EGFP line is a useful marker line for visualization of S-phase progression in live plant organs. PMID:27417498

  9. Dynamics of plant DNA replication based on PCNA visualization

    PubMed Central

    Yokoyama, Ryohei; Hirakawa, Takeshi; Hayashi, Seri; Sakamoto, Takuya; Matsunaga, Sachihiro

    2016-01-01

    DNA replication is an essential process for the copying of genomic information in living organisms. Imaging of DNA replication in tissues and organs is mainly performed using fixed cells after incorporation of thymidine analogs. To establish a useful marker line to measure the duration of DNA replication and analyze the dynamics of DNA replication, we focused on the proliferating cell nuclear antigen (PCNA), which functions as a DNA sliding clamp for replicative DNA polymerases and is an essential component of replisomes. In this study we produced an Arabidopsis thaliana line expressing PCNA1 fused with the green fluorescent protein under the control of its own promoter (pAtPCNA1::AtPCNA1-EGFP). The duration of the S phase measured using the expression line was consistent with that measured after incorporation of a thymidine analog. Live cell imaging revealed that three distinct nuclear localization patterns (whole, dotted, and speckled) were sequentially observable. These whole, dotted, and speckled patterns of subnuclear AtPCNA1 signals were indicative of the G1 or G2 phase, early S phase and late S phase, respectively. The results indicate that the pAtPCNA1::AtPCNA1-EGFP line is a useful marker line for visualization of S-phase progression in live plant organs. PMID:27417498

  10. Ultrasonic Periodontal Probing Based on the Dynamic Wavelet Fingerprint

    NASA Astrophysics Data System (ADS)

    Hinders, Mark K.; Hou, Jidong

    2005-04-01

    Manual pocket depth probing has been widely used as a retrospective diagnosis method in periodontics. However, numerous studies have questioned its ability to accurately measure the anatomic pocket depth. In this paper, an ultrasonic periodontal probing method is described, which involves using a hollow water-filled probe to focus a narrow beam of ultrasound energy into and out of the periodontal pocket, followed by automatic processing of pulse-echo signals to obtain the periodontal pocket depth. The signal processing algorithm consists of three steps: peak detection/characterization, peak classification and peak identification. A dynamic wavelet fingerprint (DWFP) technique was first applied to detect suspected scatterers in the A-scan signal and generate a two-dimensional black and white pattern to characterize the local transient signal corresponding to each scatterer. These DWFP patterns were then classified by a two-dimensional FFT procedure and mapped to an inclination index curve. The location of the pocket bottom was identified as the third broad peak in the inclination index curve. The algorithm was tested on full mouth probing data from two sequential visits of 14 patients. Its performance was evaluated by comparing ultrasonic probing results with that of full-mouth manual probing at the same sites, which was taken as the `gold standard'.

  11. Ultrasonic Periodontal Probing Based on the Dynamic Wavelet Fingerprint

    NASA Astrophysics Data System (ADS)

    Hou, Jidong; Rose, S. Timothy; Hinders, Mark K.

    2005-12-01

    Manual pocket depth probing has been widely used as a retrospective diagnosis method in periodontics. However, numerous studies have questioned its ability to accurately measure the anatomic pocket depth. In this paper, an ultrasonic periodontal probing method is described, which involves using a hollow water-filled probe to focus a narrow beam of ultrasound energy into and out of the periodontal pocket, followed by automatic processing of pulse-echo signals to obtain the periodontal pocket depth. The signal processing algorithm consists of three steps: peak detection/characterization, peak classification, and peak identification. A dynamic wavelet fingerprint (DWFP) technique is first applied to detect suspected scatterers in the A-scan signal and generate a two-dimensional black and white pattern to characterize the local transient signal corresponding to each scatterer. These DWFP patterns are then classified by a two-dimensional FFT procedure and mapped to an inclination index curve. The location of the pocket bottom was identified as the third broad peak in the inclination index curve. The algorithm is tested on full-mouth probing data from two sequential visits of 14 patients. Its performance is evaluated by comparing ultrasonic probing results with that of full-mouth manual probing at the same sites, which is taken as the "gold standard."

  12. An Extension Dynamic Model Based on BDI Agent

    NASA Astrophysics Data System (ADS)

    Yu, Wang; Feng, Zhu; Hua, Geng; WangJing, Zhu

    this paper's researching is based on the model of BDI Agent. Firstly, This paper analyze the deficiencies of the traditional BDI Agent model, Then propose an extension dynamic model of BDI Agent based on the traditional ones. It can quickly achieve the internal interaction of the tradition model of BDI Agent, deal with complex issues under dynamic and open environment and achieve quick reaction of the model. The new model is a natural and reasonable model by verifying the origin of civilization using the model of monkeys to eat sweet potato based on the design of the extension dynamic model. It is verified to be feasible by comparing the extended dynamic BDI Agent model with the traditional BDI Agent Model uses the SWARM, it has important theoretical significance.

  13. A suite of pulse sequences based on multiple sequential acquisitions at one and two radiofrequency channels for solid-state magic-angle spinning NMR studies of proteins.

    PubMed

    Sharma, Kshama; Madhu, Perunthiruthy K; Mote, Kaustubh R

    2016-08-01

    One of the fundamental challenges in the application of solid-state NMR is its limited sensitivity, yet a majority of experiments do not make efficient use of the limited polarization available. The loss in polarization in a single acquisition experiment is mandated by the need to select out a single coherence pathway. In contrast, sequential acquisition strategies can encode more than one pathway in the same experiment or recover unused polarization to supplement a standard experiment. In this article, we present pulse sequences that implement sequential acquisition strategies on one and two radiofrequency channels with a combination of proton and carbon detection to record multiple experiments under magic-angle spinning. We show that complementary 2D experiments such as [Formula: see text] and [Formula: see text] or DARR and [Formula: see text], and 3D experiments such as [Formula: see text] and [Formula: see text], or [Formula: see text] and [Formula: see text]  can be combined in a single experiment to ensure time savings of at least 40 %. These experiments can be done under fast or slow-moderate magic-angle spinning frequencies aided by windowed [Formula: see text] acquisition and homonulcear decoupling. The pulse sequence suite is further expanded by including pathways that allow the recovery of residual polarization, the so-called 'afterglow' pathways, to encode a number of pulse sequences to aid in assignments and chemical-shift mapping. PMID:27364976

  14. Sequential on-line C-terminal sequencing of peptides based on carboxypeptidase Y digestion and optically gated capillary electrophoresis with laser-induced fluorescence detection.

    PubMed

    Tian, Miaomiao; Zhang, Ning; Liu, Xiaoxia; Guo, Liping; Yang, Li

    2016-08-12

    We report a novel method for sequential on-line C-terminal sequencing of peptides, which combines carboxypeptidase Y (CPY) digestion with on-line derivatization and optically gated capillary electrophoresis with laser-induced fluorescence detection (OGCE-LIF). Various factors that may affect the C-terminal sequencing were investigated and optimized. High repeatability of on-line derivatization and the sequential OGCE-LIF assay of amino acids (AAs) was achieved with relative standard deviation (RSD) (n=20) less than 1.5% and 3.2% for migration time and peak height, respectively. A total of 13 AAs was efficiently separated in the present study, indicating that the method can be used for sequencing of peptides consisting of the 13 AAs studied. Using two synthesized N-terminally blocked peptides as test examples, we show that the present method can on-line monitor the released AAs with a temporal resolution of 50s during the entire CPY digestion process. The rates of AA release as a function of digestion time were easily measured; thus, the AA sequence of the peptide was determined with just one OGCE assay. Our study indicates the present approach is an effective, reliable, and convenient method for rapid analysis of the C-terminal sequence of peptides, with potential application in peptide analysis and proteome research. PMID:27425760

  15. Sequentially pulsed traveling wave accelerator

    DOEpatents

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  16. Hybrid Computerized Adaptive Testing: From Group Sequential Design to Fully Sequential Design

    ERIC Educational Resources Information Center

    Wang, Shiyu; Lin, Haiyan; Chang, Hua-Hua; Douglas, Jeff

    2016-01-01

    Computerized adaptive testing (CAT) and multistage testing (MST) have become two of the most popular modes in large-scale computer-based sequential testing. Though most designs of CAT and MST exhibit strength and weakness in recent large-scale implementations, there is no simple answer to the question of which design is better because different…

  17. Managing numerical errors in random sequential adsorption

    NASA Astrophysics Data System (ADS)

    Cieśla, Michał; Nowak, Aleksandra

    2016-09-01

    Aim of this study is to examine the influence of a finite surface size and a finite simulation time on a packing fraction estimated using random sequential adsorption simulations. The goal of particular interest is providing hints on simulation setup to achieve desired level of accuracy. The analysis is based on properties of saturated random packing of disks on continuous and flat surfaces of different sizes.

  18. Sequential and Parallel Algorithms for Spherical Interpolation

    NASA Astrophysics Data System (ADS)

    De Rossi, Alessandra

    2007-09-01

    Given a large set of scattered points on a sphere and their associated real values, we analyze sequential and parallel algorithms for the construction of a function defined on the sphere satisfying the interpolation conditions. The algorithms we implemented are based on a local interpolation method using spherical radial basis functions and the Inverse Distance Weighted method. Several numerical results show accuracy and efficiency of the algorithms.

  19. Parameterizing Coefficients of a POD-Based Dynamical System

    NASA Technical Reports Server (NTRS)

    Kalb, Virginia L.

    2010-01-01

    A method of parameterizing the coefficients of a dynamical system based of a proper orthogonal decomposition (POD) representing the flow dynamics of a viscous fluid has been introduced. (A brief description of POD is presented in the immediately preceding article.) The present parameterization method is intended to enable construction of the dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers. The need for this or a similar method arises as follows: A procedure that includes direct numerical simulation followed by POD, followed by Galerkin projection to a dynamical system has been proven to enable representation of flow dynamics by a low-dimensional model at the Reynolds number of the simulation. However, a more difficult task is to obtain models that are valid over a range of Reynolds numbers. Extrapolation of low-dimensional models by use of straightforward Reynolds-number-based parameter continuation has proven to be inadequate for successful prediction of flows. A key part of the problem of constructing a dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers is the problem of understanding and providing for the variation of the coefficients of the dynamical system with the Reynolds number. Prior methods do not enable capture of temporal dynamics over ranges of Reynolds numbers in low-dimensional models, and are not even satisfactory when large numbers of modes are used. The basic idea of the present method is to solve the problem through a suitable parameterization of the coefficients of the dynamical system. The parameterization computations involve utilization of the transfer of kinetic energy between modes as a function of Reynolds number. The thus-parameterized dynamical system accurately predicts the flow dynamics and is applicable to a range of flow problems in the dynamical regime around the Hopf bifurcation. Parameter

  20. A Blog-Based Dynamic Learning Map

    ERIC Educational Resources Information Center

    Wang, Kun Te; Huang, Yueh-Min; Jeng, Yu-Lin; Wang, Tzone-I

    2008-01-01

    Problem-based learning is a goal directed and constructive process for learners. When meeting problems, learners usually force themselves to form work groups in order to find a solution. Currently, blogs are becoming more popular and in fact has formed a community wherein people can share their learning experiences with others. Many pedagogical…

  1. Loads and low frequency dynamics - An ENVIRONET data base

    NASA Technical Reports Server (NTRS)

    Garba, John A.

    1988-01-01

    The loads and low frequency dynamics data base, part of Environet, is described with particular attention given to its development and contents. The objective of the data base is to provide the payload designer with design approaches and design data to meet STS safety requirements. Currently the data base consists of the following sections: abstract, scope, glossary, requirements, interaction with other environments, summary of the loads analysis process, design considerations, guidelines for payload design loads, information data base, and references.

  2. Dynamic Evolution Model Based on Social Network Services

    NASA Astrophysics Data System (ADS)

    Xiong, Xi; Gou, Zhi-Jian; Zhang, Shi-Bin; Zhao, Wen

    2013-11-01

    Based on the analysis of evolutionary characteristics of public opinion in social networking services (SNS), in the paper we propose a dynamic evolution model, in which opinions are coupled with topology. This model shows the clustering phenomenon of opinions in dynamic network evolution. The simulation results show that the model can fit the data from a social network site. The dynamic evolution of networks accelerates the opinion, separation and aggregation. The scale and the number of clusters are influenced by confidence limit and rewiring probability. Dynamic changes of the topology reduce the number of isolated nodes, while the increased confidence limit allows nodes to communicate more sufficiently. The two effects make the distribution of opinion more neutral. The dynamic evolution of networks generates central clusters with high connectivity and high betweenness, which make it difficult to control public opinions in SNS.

  3. Scale-invariant entropy-based theory for dynamic ordering

    SciTech Connect

    Mahulikar, Shripad P. E-mail: spm@aero.iitb.ac.in; Kumari, Priti

    2014-09-01

    Dynamically Ordered self-organized dissipative structure exists in various forms and at different scales. This investigation first introduces the concept of an isolated embedding system, which embeds an open system, e.g., dissipative structure and its mass and/or energy exchange with its surroundings. Thereafter, scale-invariant theoretical analysis is presented using thermodynamic principles for Order creation, existence, and destruction. The sustainability criterion for Order existence based on its structured mass and/or energy interactions with the surroundings is mathematically defined. This criterion forms the basis for the interrelationship of physical parameters during sustained existence of dynamic Order. It is shown that the sufficient condition for dynamic Order existence is approached if its sustainability criterion is met, i.e., its destruction path is blocked. This scale-invariant approach has the potential to unify the physical understanding of universal dynamic ordering based on entropy considerations.

  4. Dynamic Strategic Planning in a Professional Knowledge-Based Organization

    ERIC Educational Resources Information Center

    Olivarius, Niels de Fine; Kousgaard, Marius Brostrom; Reventlow, Susanne; Quelle, Dan Grevelund; Tulinius, Charlotte

    2010-01-01

    Professional, knowledge-based institutions have a particular form of organization and culture that makes special demands on the strategic planning supervised by research administrators and managers. A model for dynamic strategic planning based on a pragmatic utilization of the multitude of strategy models was used in a small university-affiliated…

  5. A fast dynamic mode in rare earth based glasses

    NASA Astrophysics Data System (ADS)

    Zhao, L. Z.; Xue, R. J.; Zhu, Z. G.; Ngai, K. L.; Wang, W. H.; Bai, H. Y.

    2016-05-01

    Metallic glasses (MGs) usually exhibit only slow β-relaxation peak, and the signature of the fast dynamic is challenging to be observed experimentally in MGs. We report a general and unusual fast dynamic mode in a series of rare earth based MGs manifested as a distinct fast β'-relaxation peak in addition to slow β-relaxation and α-relaxation peaks. We show that the activation energy of the fast β'-relaxation is about 12RTg and is equivalent to the activation of localized flow event. The coupling of these dynamic processes as well as their relationship with glass transition and structural heterogeneity is discussed.

  6. A fast dynamic mode in rare earth based glasses.

    PubMed

    Zhao, L Z; Xue, R J; Zhu, Z G; Ngai, K L; Wang, W H; Bai, H Y

    2016-05-28

    Metallic glasses (MGs) usually exhibit only slow β-relaxation peak, and the signature of the fast dynamic is challenging to be observed experimentally in MGs. We report a general and unusual fast dynamic mode in a series of rare earth based MGs manifested as a distinct fast β'-relaxation peak in addition to slow β-relaxation and α-relaxation peaks. We show that the activation energy of the fast β'-relaxation is about 12RTg and is equivalent to the activation of localized flow event. The coupling of these dynamic processes as well as their relationship with glass transition and structural heterogeneity is discussed. PMID:27250316

  7. Kinematic and dynamic analysis of an anatomically based knee joint.

    PubMed

    Lee, Kok-Meng; Guo, Jiajie

    2010-05-01

    This paper presents a knee-joint model to provide a better understanding on the interaction between natural joints and artificial mechanisms for design and control of rehabilitation exoskeletons. The anatomically based knee model relaxes several commonly made assumptions that approximate a human knee as engineering pin-joint in exoskeleton design. Based on published MRI data, we formulate the kinematics of a knee-joint and compare three mathematical approximations; one model bases on two sequential circles rolling a flat plane; and the other two are mathematically differentiable ellipses-based models with and without sliding at the contact. The ellipses-based model taking sliding contact into accounts shows that the rolling-sliding ratio of a knee-joint is not a constant but has an average value consistent with published measurements. This knee-joint kinematics leads to a physically more accurate contact-point trajectory than methods based on multiple circles or lines, and provides a basis to derive a knee-joint kinetic model upon which the effects of a planar exoskeleton mechanism on the internal joint forces and torque during flexion can be numerically investigated. Two different knee-joint kinetic models (pin-joint approximation and anatomically based model) are compared against a condition with no exoskeleton. The leg and exoskeleton form a closed kinematic chain that has a significant effect on the joint forces in the knee. Human knee is more tolerant than pin-joint in negotiating around a singularity but its internal forces increase with the exoskeleton mass-to-length ratio. An oversimplifying pin-joint approximation cannot capture the finite change in the knee forces due to the singularity effect. PMID:20189182

  8. A Cumulant-based Analysis of Nonlinear Magnetospheric Dynamics

    SciTech Connect

    Jay R. Johnson; Simon Wing

    2004-01-28

    Understanding magnetospheric dynamics and predicting future behavior of the magnetosphere is of great practical interest because it could potentially help to avert catastrophic loss of power and communications. In order to build good predictive models it is necessary to understand the most critical nonlinear dependencies among observed plasma and electromagnetic field variables in the coupled solar wind/magnetosphere system. In this work, we apply a cumulant-based information dynamical measure to characterize the nonlinear dynamics underlying the time evolution of the Dst and Kp geomagnetic indices, given solar wind magnetic field and plasma input. We examine the underlying dynamics of the system, the temporal statistical dependencies, the degree of nonlinearity, and the rate of information loss. We find a significant solar cycle dependence in the underlying dynamics of the system with greater nonlinearity for solar minimum. The cumulant-based approach also has the advantage that it is reliable even in the case of small data sets and therefore it is possible to avoid the assumption of stationarity, which allows for a measure of predictability even when the underlying system dynamics may change character. Evaluations of several leading Kp prediction models indicate that their performances are sub-optimal during active times. We discuss possible improvements of these models based on this nonparametric approach.

  9. Sequential Syndrome Decoding of Convolutional Codes

    NASA Technical Reports Server (NTRS)

    Reed, I. S.; Truong, T. K.

    1984-01-01

    The algebraic structure of convolutional codes are reviewed and sequential syndrome decoding is applied to those codes. These concepts are then used to realize by example actual sequential decoding, using the stack algorithm. The Fano metric for use in sequential decoding is modified so that it can be utilized to sequentially find the minimum weight error sequence.

  10. Sequential injection immunoassay for environmental measurements.

    PubMed

    Soh, Nobuaki; Tanaka, Mayumi; Hirakawa, Koji; Zhang, RuiQi; Nakajima, Hizuru; Nakano, Koji; Imato, Toshihiko

    2011-01-01

    Sequential injection immunoassay systems for environmental measurements based on the selective immunoreaction between antigen and antibody were described. A sequential injection analysis (SIA) technique is suitable to be applied for the procedure of enzyme-linked immunosorbent assay (ELISA), because the washing and the addition of reagent solutions can be automated by using a computer-controlled syringe pump and switching valve. We selected vitellogenin (Vg), which is a biomarker for evaluating environmental risk caused by endocrine-disrupting chemicals in the hydrosphere, and linear alkylbenzene sulfonates (LAS) and alkylphenol polyethoxylates (APEO), which are versatile surfactants, as target analytes in the flow immunoassay systems. For Vg monitoring, SIA systems based on spectrophotometric, chemiluminescence, and electrochemical determinations were constructed. On the other hand, chemiluminescence determination was applied to the detection of LAS and APEO. For APEO, an SIA system combined with surface plasmon resonance (SPR) sensor was also developed. These new sequential injection immunoassay systems are expected to be useful systems for environmental analysis. PMID:22076332

  11. Dynamic molecules: molecular dynamics for everyone. An internet-based access to molecular dynamic simulations: basic concepts.

    PubMed

    Frank, Martin; Gutbrod, Peter; Hassayoun, Chokri; von Der Lieth, Claus-W

    2003-10-01

    Molecular dynamics is a rapidly developing field of science and has become an established tool for studying the dynamic behavior of biomolecules. Although several high quality programs for performing molecular dynamic simulations are freely available, only well-trained scientists are currently able to make use of the broad scientific potential that molecular dynamic simulations offer to gain insight into structural questions at an atomic level. The "Dynamic Molecules" approach is the first internet portal that provides an interactive access to set up, perform and analyze molecular dynamic simulations. It is completely based on standard web technologies and uses only publicly available software. The aim is to open molecular dynamics techniques to a broader range of users including undergraduate students, teachers and scientists outside the bioinformatics field. The time-limiting factors are the availability of free capacity on the computing server to run the simulations and the time required to transport the history file through the internet for the animation mode. The interactive access mode of the portal is acceptable for animations of molecules having up to about 500 atoms. PMID:12908101

  12. Dynamic frequency feature selection based approach for classification of motor imageries.

    PubMed

    Luo, Jing; Feng, Zuren; Zhang, Jun; Lu, Na

    2016-08-01

    Electroencephalography (EEG) is one of the most popular techniques to record the brain activities such as motor imagery, which is of low signal-to-noise ratio and could lead to high classification error. Therefore, selection of the most discriminative features could be crucial to improve the classification performance. However, the traditional feature selection methods employed in brain-computer interface (BCI) field (e.g. Mutual Information-based Best Individual Feature (MIBIF), Mutual Information-based Rough Set Reduction (MIRSR) and cross-validation) mainly focus on the overall performance on all the trials in the training set, and thus may have very poor performance on some specific samples, which is not acceptable. To address this problem, a novel sequential forward feature selection approach called Dynamic Frequency Feature Selection (DFFS) is proposed in this paper. The DFFS method emphasized the importance of the samples that got misclassified while only pursuing high overall classification performance. In the DFFS based classification scheme, the EEG data was first transformed to frequency domain using Wavelet Packet Decomposition (WPD), which is then employed as the candidate set for further discriminatory feature selection. The features are selected one by one in a boosting manner. After one feature being selected, the importance of the correctly classified samples based on the feature will be decreased, which is equivalent to increasing the importance of the misclassified samples. Therefore, a complement feature to the current features could be selected in the next run. The selected features are then fed to a classifier trained by random forest algorithm. Finally, a time series voting-based method is utilized to improve the classification performance. Comparisons between the DFFS-based approach and state-of-art methods on BCI competition IV data set 2b have been conducted, which have shown the superiority of the proposed algorithm. PMID:27253616

  13. Random sequential adsorption of n-star objects

    NASA Astrophysics Data System (ADS)

    Shelke, Pradip B.

    2016-02-01

    Random sequential adsorption (RSA) of n-star objects (consisting of n arms of equal lengths l, originating radially outward from the center with a uniform angular spacing of 2π/n) on a two-dimensional continuum substrate is studied. For all the values of n ranging from 3 to 200, the dynamics of adsorption is found to follow a power law ρ(∞) - ρ(t) ∼ t- p, where ρ(∞) and ρ(t) are respectively saturated and instantaneous number densities of the adsorbed objects. The exponent p is found to increase monotonically with n but still remains significantly lower than 0.5, the exponent for RSA of circular discs, indicating that RSA dynamics of this class of objects is totally different than that of circular discs. The exponent p does not follow the law p = 1/df, where df is degrees of freedom of the object. Also ρ(∞) reveals a systematic n dependence and an attempt is made to understand the same. Analytical and simulation results are found to be in fair agreement, however the treatment given is based on crude approximation and more profound theory is to be sought for better understanding of the dynamics of the process.

  14. Dynamic brittle material response based on a continuum damage model

    SciTech Connect

    Chen, E.P.

    1994-12-31

    The response of brittle materials to dynamic loads was studied in this investigation based on a continuum damage model. Damage mechanism was selected to be interaction and growth of subscale cracks. Briefly, the cracks are activated by bulk tension and the density of activated cracks are described by a Weibull statistical distribution. The moduli of a cracked solid derived by Budiansky and O`Connell are then used to represent the global material degradation due to subscale cracking. This continuum damage model was originally developed to study rock fragmentation and was modified in the present study to improve on the post-limit structural response. The model was implemented into a transient dynamic explicit finite element code PRONTO 2D and then used for a numerical study involving the sudden stretching of a plate with a centrally located hole. Numerical results characterizing the dynamic responses of the material were presented. The effect of damage on dynamic material behavior was discussed.

  15. An Individual-Based Model of Zebrafish Population Dynamics Accounting for Energy Dynamics

    PubMed Central

    Beaudouin, Rémy; Goussen, Benoit; Piccini, Benjamin; Augustine, Starrlight; Devillers, James; Brion, François; Péry, Alexandre R. R.

    2015-01-01

    Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model) was coupled to an individual based model of zebrafish population dynamics (IBM model). Next, we fitted the DEB model to new experimental data on zebrafish growth and reproduction thus improving existing models. We further analysed the DEB-model and DEB-IBM using a sensitivity analysis. Finally, the predictions of the DEB-IBM were compared to existing observations on natural zebrafish populations and the predicted population dynamics are realistic. While our zebrafish DEB-IBM model can still be improved by acquiring new experimental data on the most uncertain processes (e.g. survival or feeding), it can already serve to predict the impact of compounds at the population level. PMID:25938409

  16. Perspective: A Dynamics-Based Classification of Ventricular Arrhythmias

    PubMed Central

    Weiss, James N.; Garfinkel, Alan; Karagueuzian, Hrayr S.; Nguyen, Thao P.; Olcese, Riccardo; Chen, Peng-Sheng; Qu, Zhilin

    2015-01-01

    Despite key advances in the clinical management of life-threatening ventricular arrhythmias, culminating with the development of implantable cardioverter-defibrillators and catheter ablation techniques, pharmacologic/biologic therapeutics have lagged behind. The fundamental issue is that biological targets are molecular factors. Diseases, however, represent emergent properties at the scale of the organism that result from dynamic interactions between multiple constantly changing molecular factors. For a pharmacologic/biologic therapy to be effective, it must target the dynamic processes that underlie the disease. Here we propose a classification of ventricular arrhythmias that is based on our current understanding of the dynamics occurring at the subcellular, cellular, tissue and organism scales, which cause arrhythmias by simultaneously generating arrhythmia triggers and exacerbating tissue vulnerability. The goal is to create a framework that systematically links these key dynamic factors together with fixed factors (structural and electrophysiological heterogeneity) synergistically promoting electrical dispersion and increased arrhythmia risk to molecular factors that can serve as biological targets. We classify ventricular arrhythmias into three primary dynamic categories related generally to unstable Ca cycling, reduced repolarization, and excess repolarization, respectively. The clinical syndromes, arrhythmia mechanisms, dynamic factors and what is known about their molecular counterparts are discussed. Based on this framework, we propose a computational-experimental strategy for exploring the links between molecular factors, fixed factors and dynamic factors that underlie life-threatening ventricular arrhythmias. The ultimate objective is to facilitate drug development by creating an in silico platform to evaluate and predict comprehensively how molecular interventions affect not only a single targeted arrhythmia, but all primary arrhythmia dynamics

  17. A bit serial sequential circuit

    NASA Technical Reports Server (NTRS)

    Hu, S.; Whitaker, S.

    1990-01-01

    Normally a sequential circuit with n state variables consists of n unique hardware realizations, one for each state variable. All variables are processed in parallel. This paper introduces a new sequential circuit architecture that allows the state variables to be realized in a serial manner using only one next state logic circuit. The action of processing the state variables in a serial manner has never been addressed before. This paper presents a general design procedure for circuit construction and initialization. Utilizing pass transistors to form the combinational next state forming logic in synchronous sequential machines, a bit serial state machine can be realized with a single NMOS pass transistor network connected to shift registers. The bit serial state machine occupies less area than other realizations which perform parallel operations. Moreover, the logical circuit of the bit serial state machine can be modified by simply changing the circuit input matrix to develop an adaptive state machine.

  18. Sequential analysis of uncommon adverse outcomes.

    PubMed

    Morton, A; Mengersen, K; Waterhouse, M; Steiner, S; Looke, D

    2010-10-01

    Sequential analysis of uncommon adverse outcomes (AEs) such as surgical site infections (SSIs) is desirable. Short postoperative lengths of stay (LOS) result in many SSIs occurring after discharge and they are often superficial. Deep and organ space (complex) SSIs occur less frequently but are detected more reliably and are suitable for monitoring wound care. Those occurring post-discharge usually require readmissison and can be counted accurately. Sequential analysis of meticillin-resistant Staphylococcus aureus bacteraemia is also needed. The key to prevention is to implement systems based on evidence, e.g. using 'bundles' and checklists. Regular mortality and morbidity audit meetings are required and these may need to be followed by independent audits. Sequential statistical analysis is desirable for data presentation, to detect changes, and to discourage tampering with processes when occasional AEs occur in a reliable system. Tabulations and cumulative observed minus expected (O-E) charts and funnel plots are valuable, supplemented in the presence of apparent 'runs' of AEs by cumulative sum analysis. Used prospectively, they may enable staff to visualise and detect patterns or shifts in rates and counts that might not otherwise be apparent. PMID:20656377

  19. Universality of sequential quantum measurements

    NASA Astrophysics Data System (ADS)

    Heinosaari, Teiko; Miyadera, Takayuki

    2015-02-01

    We show that any jointly measurable pair of quantum observables can be obtained in a sequential measurement scheme, even if the second observable will be decided after the first measurement. This means that it is possible to perform a measurement of any quantum observable in a way that does not disturb the subsequent measurements more than is dictated by joint measurability. Only measurements with a specific structure have this universality feature. As a supplementing result, we provide a characterization of all possible joint measurements obtained from a sequential measurement lacking universality.

  20. Altazimuth mount based dynamic calibration method for GNSS attitude measurement

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; He, Tao; Sun, Shaohua; Gu, Qing

    2015-02-01

    As the key process to ensure the test accuracy and quality, the dynamic calibration of the GNSS attitude measuring instrument is often embarrassed by the lack of the rigid enough test platform and an accurate enough calibration reference. To solve the problems, a novel dynamic calibration method for GNSS attitude measurement based on altazimuth mount is put forward in this paper. The principle and implementation of this method are presented, and then the feasibility and usability of the method are analyzed in detail involving the applicability of the mount, calibrating precision, calibrating range, base line rigidity and the satellite signal involved factors. Furthermore, to verify and test the method, a confirmatory experiment is carried out with the survey ship GPS attitude measuring instrument, and the experimental results prove that it is a feasible way to the dynamic calibration for GNSS attitude measurement.

  1. Quantum Dynamics with Gaussian Bases Defined by the Quantum Trajectories.

    PubMed

    Gu, Bing; Garashchuk, Sophya

    2016-05-19

    Development of a general approach to construction of efficient high-dimensional bases is an outstanding challenge in quantum dynamics describing large amplitude motion of molecules and fragments. A number of approaches, proposed over the years, utilize Gaussian bases whose parameters are somehow-usually by propagating classical trajectories or by solving coupled variational equations-tailored to the shape of a wave function evolving in time. In this paper we define the time-dependent Gaussian bases through an ensemble of quantum or Bohmian trajectories, known to provide a very compact representation of a wave function due to conservation of the probability density associated with each trajectory. Though the exact numerical implementation of the quantum trajectory dynamics itself is, generally, impractical, the quantum trajectories can be obtained from the wave function expanded in a basis. The resulting trajectories are used to guide compact Gaussian bases, as illustrated on several model problems. PMID:26735750

  2. AN INDIVIDUAL-BASED MODEL OF COTTUS POPULATION DYNAMICS

    EPA Science Inventory

    We explored population dynamics of a southern Appalachian population of Cottus bairdi using a spatially-explicit, individual-based model. The model follows daily growth, mortality, and spawning of individuals as a function of flow and temperature. We modeled movement of juveniles...

  3. Sequential Processes In Image Generation.

    ERIC Educational Resources Information Center

    Kosslyn, Stephen M.; And Others

    1988-01-01

    Results of three experiments are reported, which indicate that images of simple two-dimensional patterns are formed sequentially. The subjects included 48 undergraduates and 16 members of the Harvard University (Cambridge, Mass.) community. A new objective methodology indicates that images of complex letters require more time to generate. (TJH)

  4. Sequential Effects in Essay Ratings

    ERIC Educational Resources Information Center

    Attali, Yigal

    2011-01-01

    Contrary to previous research on sequential ratings of student performance, this study found that professional essay raters of a large-scale standardized testing program produced ratings that were drawn toward previous ratings, creating an assimilation effect. Longer intervals between the two adjacent ratings and higher degree of agreement with…

  5. Molecular spectroscopy and dynamics: a polyad-based perspective.

    PubMed

    Herman, Michel; Perry, David S

    2013-07-01

    The efficiency and insight of global, polyad-based modeling in overtone spectroscopy and dynamics is demonstrated. Both vibration and vibration-rotation polyads are considered. The spectroscopic implications of polyad Hamiltonians derive from their ability to account for the detailed line positions and intensities of spectral features and their unique predictive power. The dynamical implications of polyad Hamiltonians include classical bifurcations that lead to the birth of new vibrational modes and intramolecular vibrational-rotational energy redistribution over multiple timescales. The literature is reviewed, with emphasis on acetylene results. PMID:23646355

  6. Panoramic dynamic data acquisition system based on unmanned helicopter

    NASA Astrophysics Data System (ADS)

    Yao, Yigang; Zhao, Shuguang; Lin, Zhaorong; Wen, Gaojin; Zhang, Qian; Zhang, Weiwei

    2012-10-01

    In recent years, the archaeological tourism has rapidly been developed all over the world, and it has become more and more popular. However, the scope of the human activities has been restricted by complicated geographical terrain, and the popularization of archaeological tourism has been hampered. For the purpose of solving the above problem, the archaeological tourism system of the panoramic dynamic data acquisition system based on unmanned helicopter is designed, and we got the image of the Chinese Ming Dynasty Great Wall realtime 360˚ panoramic dynamic monitor. The applying of this system will increase the scope of the archaeological tourism activities.

  7. Characterizing cerebrovascular dynamics with the wavelet-based multifractal formalism

    NASA Astrophysics Data System (ADS)

    Pavlov, A. N.; Abdurashitov, A. S.; Sindeeva, O. A.; Sindeev, S. S.; Pavlova, O. N.; Shihalov, G. M.; Semyachkina-Glushkovskaya, O. V.

    2016-01-01

    Using the wavelet-transform modulus maxima (WTMM) approach we study the dynamics of cerebral blood flow (CBF) in rats aiming to reveal responses of macro- and microcerebral circulations to changes in the peripheral blood pressure. We show that the wavelet-based multifractal formalism allows quantifying essentially different reactions in the CBF-dynamics at the level of large and small cerebral vessels. We conclude that unlike the macrocirculation that is nearly insensitive to increased peripheral blood pressure, the microcirculation is characterized by essential changes of the CBF-complexity.

  8. Dynamic Co-Operative Scheduling Based on HLA

    NASA Astrophysics Data System (ADS)

    Shirase, Keiichi; Wakamatsu, Hidefumi; Tsumaya, Akira; Arai, Eiji

    In an advanced factory, higher and higher flexibility is required to meet a great variety of customers' requirements. In this environment, a dynamic management architecture is required for distributed production system. In this paper, a newly distributed simulation architecture called HLA (High Level Architecture) is utilized to achieve a distributed scheduling simulation for dynamic work assignment and flexible working group configuration in a distributed production system. It is verified that the distributed scheduling simulation based on HLA is effective to achieve higher flexibility for a distributed production system, by some case studies.

  9. Evaluation of energy expenditure in adult spring Chinook salmon migrating upstream in the Columbia River Basin: an assessment based on sequential proximate analysis

    USGS Publications Warehouse

    Mesa, M.G.; Magie, C.D.

    2006-01-01

    The upstream migration of adult anadromous salmonids in the Columbia River Basin (CRB) has been dramatically altered and fish may be experiencing energetically costly delays at dams. To explore this notion, we estimated the energetic costs of migration and reproduction of Yakima River-bound spring Chinook salmon Oncorhynchus tshawytscha using a sequential analysis of their proximate composition (i.e., percent water, fat, protein, and ash). Tissues (muscle, viscera, and gonad) were sampled from fish near the start of their migration (Bonneville Dam), at a mid point (Roza Dam, 510 km upstream from Bonneville Dam) and from fresh carcasses on the spawning grounds (about 100 km above Roza Dam). At Bonneville Dam, the energy reserves of these fish were remarkably high, primarily due to the high percentage of fat in the muscle (18-20%; energy content over 11 kJ g-1). The median travel time for fish from Bonneville to Roza Dam was 27 d and ranged from 18 to 42 d. Fish lost from 6 to 17% of their energy density in muscle, depending on travel time. On average, fish taking a relatively long time for migration between dams used from 5 to 8% more energy from the muscle than faster fish. From the time they passed Bonneville Dam to death, these fish, depending on gender, used 95-99% of their muscle and 73-86% of their viscera lipid stores. Also, both sexes used about 32% of their muscular and very little of their visceral protein stores. However, we were unable to relate energy use and reproductive success to migration history. Our results suggest a possible influence of the CRB hydroelectric system on adult salmonid energetics.

  10. MIMO radar 3D imaging based on combined amplitude and total variation cost function with sequential order one negative exponential form.

    PubMed

    Ma, Changzheng; Yeo, Tat Soon; Zhao, Yongbo; Feng, Junjie

    2014-05-01

    In inverse synthetic aperture radar (ISAR) imaging, a target is usually regarded as consist of a few strong (specular) scatterers and the distribution of these strong scatterers is sparse in the imaging volume. In this paper, we propose to incorporate the sparse signal recovery method in 3D multiple-input multiple-output radar imaging algorithm. Sequential order one negative exponential (SOONE) function, which forms homotopy between 1 and 0 norms, is proposed to measure the sparsity. Gradient projection is used to solve a constrained nonconvex SOONE function minimization problem and recover the sparse signal. However, while the gradient projection method is computationally simple, it is not robust when a matrix in the algorithm is ill conditioned. We thus further propose using diagonal loading and singular value decomposition methods to improve the robustness of the algorithm. In order to handle targets with large flat surfaces, a combined amplitude and total-variation objective function is also proposed to regularize the shapes of the flat surfaces. Simulation results show that the proposed gradient projection of SOONE function method is better than orthogonal matching pursuit, CoSaMp, l1-magic, Bayesian method with Laplace prior, smoothed l0 method, and l1-ls in high SNR cases for recovery of ± 1 random spikes sparse signal. The quality of the simulated 3D images and real data ISAR images obtained using the new method is better than that of the conventional correlation method and minimum l2 norm method, and competitive to the aforementioned sparse signal recovery algorithms. PMID:24818240

  11. Middleware for Processing Message Queues with Elasticity Support and Sequential Integrity of Asynchronous Message Processing

    NASA Astrophysics Data System (ADS)

    Henrique Teixeira, Eduardo; Patrícia Favacho de Araújo, Aletéia

    2015-10-01

    Elasticity in computing refers to dynamically adjusting the amount of allocated resources to process a distributed application. In order to achieve this, mechanisms are needed to avoid the phenomenon of the elasticity threshold detection moving constantly up or down. The existing work fails to deliver sequential integrity of asynchronous messages processing and the asymmetries of data distribution to achieve parallel consumption. This paper fills this gaps and proposes a middleware solution to dynamically analyze the flow of message queue, and a mechanism to increase the parallelized consumption based on the output behavior. An architecture for IOD (Increase On Demand) middleware is presented, with support for the increase and decrease of thread's to cope with the growth of message queues, using the technique of limit-based heuristics over a given period of time and grouping messages into sub-queues based on classification criteria.

  12. Mosquito population dynamics from cellular automata-based simulation

    NASA Astrophysics Data System (ADS)

    Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

    2016-02-01

    In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

  13. Rule-based reasoning for system dynamics in cell systems.

    PubMed

    Jeong, Euna; Nagasaki, Masao; Miyano, Satoru

    2008-01-01

    A system-dynamics-centered ontology, called the Cell System Ontology (CSO), has been developed for representation of diverse biological pathways. Many of the pathway data based on the ontology have been created from databases via data conversion or curated by expert biologists. It is essential to validate the pathway data which may cause unexpected issues such as semantic inconsistency and incompleteness. This paper discusses three criteria for validating the pathway data based on CSO as follows: (1) structurally correct models in terms of Petri nets, (2) biologically correct models to capture biological meaning, and (3) systematically correct models to reflect biological behaviors. Simultaneously, we have investigated how logic-based rules can be used for the ontology to extend its expressiveness and to complement the ontology by reasoning, which aims at qualifying pathway knowledge. Finally, we show how the proposed approach helps exploring dynamic modeling and simulation tasks without prior knowledge. PMID:19425120

  14. Sequential and combined acceleration tests for crystalline Si photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Masuda, Atsushi; Yamamoto, Chizuko; Uchiyama, Naomi; Ueno, Kiyoshi; Yamazaki, Toshiharu; Mitsuhashi, Kazunari; Tsutsumida, Akihiro; Watanabe, Jyunichi; Shirataki, Jyunko; Matsuda, Keiko

    2016-04-01

    The sequential combination test for photovoltaic modules is effective for accelerating degradation to shorten the test time and for reproducing degradation phenomena observed in modules exposed outdoors for a long time. The damp-heat (DH) test, thermal-cycle (TC) test, humidity-freeze (HF) test or dynamic mechanical load (DML) test is combined for the test modules. It was confirmed that chemical corrosion degradation or physical mechanical degradation is reproduced by the combination of the above tests. Cracks on the back sheet and delamination, often observed upon outdoor exposure, were well reproduced by the combination of DH and TC tests and TC and HF tests, respectively. Sequential DH and TC tests and DML and TC tests accelerated the degradation. These sequential tests are expected to be effective in reducing the required time of indoor testing for ensuring long-term reliability.

  15. Dynamic contact angle of water-based titanium oxide nanofluid

    PubMed Central

    2013-01-01

    This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO2-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading, the wedge film viscosity is the dominant dissipative mechanism. A theoretical model based on combination of molecular kinetic theory and hydrodynamic theory which incorporates non-Newtonian viscosity of solutions is used. The model agreement with experimental data is reasonable. Complex interparticle interactions, local pinning of the contact line, and variations in solid–liquid interfacial tension are attributed to errors. PMID:23759071

  16. Broadband optical switch based on liquid crystal dynamic scattering.

    PubMed

    Geis, M W; Bos, P J; Liberman, V; Rothschild, M

    2016-06-27

    This work demonstrates a novel broadband optical switch, based on dynamic-scattering effect in liquid crystals (LCs). Dynamic-scattering-mode technology was developed for display applications over four decades ago, but was displaced in favor of the twisted-nematic LCs. However, with the recent development of more stable LCs, dynamic scattering provides advantages over other technologies for optical switching. We demonstrate broadband polarization-insensitive attenuation of light directly passing thought the cell by 4 to 5 orders of magnitude at 633 nm. The attenuation is accomplished by light scattering to higher angles. Switching times of 150 μs to 10% transmission have been demonstrated. No degradation of devices is found after hundreds of switching cycles. The light-rejection mechanism is due to scattering, induced by disruption of LC director orientation with dopant ion motion with an applied electric field. Angular dependence of scattering is characterized as a function of bias voltage. PMID:27410544

  17. Momentum-Based Dynamics for Spacecraft with Chained Revolute Appendages

    NASA Technical Reports Server (NTRS)

    Queen, Steven; London, Ken; Gonzalez, Marcelo

    2005-01-01

    An efficient formulation is presented for a sub-class of multi-body dynamics problems that involve a six degree-of-freedom base body and a chain of N rigid linkages connected in series by single degree-of-freedom revolute joints. This general method is particularly well suited for simulations of spacecraft dynamics and control that include the modeling of an orbiting platform with or without internal degrees of freedom such as reaction wheels, dampers, and/or booms. In the present work, particular emphasis is placed on dynamic simulation of multi-linkage robotic manipulators. The differential equations of motion are explicitly given in terms of linear and angular momentum states, which can be evaluated recursively along a serial chain of linkages for an efficient real-time solution on par with the best of the O(N3) methods.

  18. Tunable dynamics of microtubule-based active isotropic gels

    PubMed Central

    Henkin, Gil; DeCamp, Stephen J.; Chen, Daniel T. N.; Sanchez, Tim; Dogic, Zvonimir

    2014-01-01

    We investigate the dynamics of an active gel of bundled microtubules (MTs) that is driven by clusters of kinesin molecular motors. Upon the addition of ATP, the coordinated action of thousands of molecular motors drives the gel to a highly dynamical turbulent-like state that persists for hours and is only limited by the stability of constituent proteins and the availability of the chemical fuel. We characterize how enhanced transport and emergent macroscopic flows of active gels depend on relevant molecular parameters, including ATP, kinesin motor and depletant concentrations, MT volume fraction, as well as the stoichiometry of the constituent motor clusters. Our results show that the dynamical and structural properties of MT-based active gels are highly tunable. They also indicate existence of an optimal concentration of molecular motors that maximize far-from-equilibrium activity of active isotropic MT gels. PMID:25332391

  19. Hippocampal Attractor Dynamics Predict Memory-Based Decision Making.

    PubMed

    Steemers, Ben; Vicente-Grabovetsky, Alejandro; Barry, Caswell; Smulders, Peter; Schröder, Tobias Navarro; Burgess, Neil; Doeller, Christian F

    2016-07-11

    Memories are thought to be retrieved by attractor dynamics if a given input is sufficiently similar to a stored attractor state [1-5]. The hippocampus, a region crucial for spatial navigation [6-12] and episodic memory [13-18], has been associated with attractor-based computations [5, 9], receiving support from the way rodent place cells "remap" nonlinearly between spatial representations [19-22]. In humans, nonlinear response patterns have been reported in perceptual categorization tasks [23-25]; however, it remains elusive whether human memory retrieval is driven by attractor dynamics and what neural mechanisms might underpin them. To test this, we used a virtual reality [7, 11, 26-28] task where participants learned object-location associations within two distinct virtual reality environments. Participants were subsequently exposed to four novel intermediate environments, generated by linearly morphing the background landscapes of the familiar environments, while tracking fMRI activity. We show that linear changes in environmental context cause linear changes in activity patterns in sensory cortex but cause dynamic, nonlinear changes in both hippocampal activity pattern and remembered locations. Furthermore, the sigmoidal response in the hippocampus scaled with the strength of the sigmoidal pattern in spatial memory. These results indicate that mnemonic decisions in an ambiguous novel context relate to putative attractor dynamics in the hippocampus, which support the dynamic remapping of memories. PMID:27345167

  20. Prediction-based dynamic load-sharing heuristics

    NASA Technical Reports Server (NTRS)

    Goswami, Kumar K.; Devarakonda, Murthy; Iyer, Ravishankar K.

    1993-01-01

    The authors present dynamic load-sharing heuristics that use predicted resource requirements of processes to manage workloads in a distributed system. A previously developed statistical pattern-recognition method is employed for resource prediction. While nonprediction-based heuristics depend on a rapidly changing system status, the new heuristics depend on slowly changing program resource usage patterns. Furthermore, prediction-based heuristics can be more effective since they use future requirements rather than just the current system state. Four prediction-based heuristics, two centralized and two distributed, are presented. Using trace driven simulations, they are compared against random scheduling and two effective nonprediction based heuristics. Results show that the prediction-based centralized heuristics achieve up to 30 percent better response times than the nonprediction centralized heuristic, and that the prediction-based distributed heuristics achieve up to 50 percent improvements relative to their nonprediction counterpart.

  1. Sequential decision rules for failure detection

    NASA Technical Reports Server (NTRS)

    Chow, E. Y.; Willsky, A. S.

    1981-01-01

    The formulation of the decision making of a failure detection process as a Bayes sequential decision problem (BSDP) provides a simple conceptualization of the decision rule design problem. As the optimal Bayes rule is not computable, a methodology that is based on the Baysian approach and aimed at a reduced computational requirement is developed for designing suboptimal rules. A numerical algorithm is constructed to facilitate the design and performance evaluation of these suboptimal rules. The result of applying this design methodology to an example shows that this approach is a useful one.

  2. Dynamic reasoning in a knowledge-based system

    NASA Technical Reports Server (NTRS)

    Rao, Anand S.; Foo, Norman Y.

    1988-01-01

    Any space based system, whether it is a robot arm assembling parts in space or an onboard system monitoring the space station, has to react to changes which cannot be foreseen. As a result, apart from having domain-specific knowledge as in current expert systems, a space based AI system should also have general principles of change. This paper presents a modal logic which can not only represent change but also reason with it. Three primitive operations, expansion, contraction and revision are introduced and axioms which specify how the knowledge base should change when the external world changes are also specified. Accordingly the notion of dynamic reasoning is introduced, which unlike the existing forms of reasoning, provide general principles of change. Dynamic reasoning is based on two main principles, namely minimize change and maximize coherence. A possible-world semantics which incorporates the above two principles is also discussed. The paper concludes by discussing how the dynamic reasoning system can be used to specify actions and hence form an integral part of an autonomous reasoning and planning system.

  3. Hybrid Model Predictive Control for Sequential Decision Policies in Adaptive Behavioral Interventions

    PubMed Central

    Dong, Yuwen; Deshpande, Sunil; Rivera, Daniel E.; Downs, Danielle S.; Savage, Jennifer S.

    2015-01-01

    Control engineering offers a systematic and efficient method to optimize the effectiveness of individually tailored treatment and prevention policies known as adaptive or “just-in-time” behavioral interventions. The nature of these interventions requires assigning dosages at categorical levels, which has been addressed in prior work using Mixed Logical Dynamical (MLD)-based hybrid model predictive control (HMPC) schemes. However, certain requirements of adaptive behavioral interventions that involve sequential decision making have not been comprehensively explored in the literature. This paper presents an extension of the traditional MLD framework for HMPC by representing the requirements of sequential decision policies as mixed-integer linear constraints. This is accomplished with user-specified dosage sequence tables, manipulation of one input at a time, and a switching time strategy for assigning dosages at time intervals less frequent than the measurement sampling interval. A model developed for a gestational weight gain (GWG) intervention is used to illustrate the generation of these sequential decision policies and their effectiveness for implementing adaptive behavioral interventions involving multiple components. PMID:25635157

  4. TDRSS-user orbit determination using batch least-squares and sequential methods

    NASA Technical Reports Server (NTRS)

    Oza, D. H.; Jones, T. L.; Hakimi, M.; Samii, Mina V.; Doll, C. E.; Mistretta, G. D.; Hart, R. C.

    1993-01-01

    The Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) commissioned Applied Technology Associates, Incorporated, to develop the Real-Time Orbit Determination/Enhanced (RTOD/E) system on a Disk Operating System (DOS)-based personal computer (PC) as a prototype system for sequential orbit determination of spacecraft. This paper presents the results of a study to compare the orbit determination accuracy for a Tracking and Data Relay Satellite System (TDRSS) user spacecraft, Landsat-4, obtained using RTOD/E, operating on a PC, with the accuracy of an established batch least-squares system, the Goddard Trajectory Determination System (GTDS), and operating on a mainframe computer. The results of Landsat-4 orbit determination will provide useful experience for the Earth Observing System (EOS) series of satellites. The Landsat-4 ephemerides were estimated for the January 17-23, 1991, timeframe, during which intensive TDRSS tracking data for Landsat-4 were available. Independent assessments were made of the consistencies (overlap comparisons for the batch case and covariances and the first measurement residuals for the sequential case) of solutions produced by the batch and sequential methods. The forward-filtered RTOD/E orbit solutions were compared with the definitive GTDS orbit solutions for Landsat-4; the solution differences were less than 40 meters after the filter had reached steady state.

  5. Evaluation of Landsat-4 orbit determination accuracy using batch least-squares and sequential methods

    NASA Technical Reports Server (NTRS)

    Oza, D. H.; Jones, T. L.; Feiertag, R.; Samii, M. V.; Doll, C. E.; Mistretta, G. D.; Hart, R. C.

    1993-01-01

    The Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) commissioned Applied Technology Associates, Incorporated, to develop the Real-Time Orbit Determination/Enhanced (RTOD/E) system on a Disk Operating System (DOS)-based personal computer (PC) as a prototype system for sequential orbit determination of spacecraft. This paper presents the results of a study to compare the orbit determination accuracy for a Tracking and Data Relay Satellite (TDRS) System (TDRSS) user spacecraft, Landsat-4, obtained using RTOD/E, operating on a PC, with the accuracy of an established batch least-squares system, the Goddard Trajectory Determination System (GTDS), operating on a mainframe computer. The results of Landsat-4 orbit determination will provide useful experience for the Earth Observing System (EOS) series of satellites. The Landsat-4 ephemerides were estimated for the May 18-24, 1992, timeframe, during which intensive TDRSS tracking data for Landsat-4 were available. During this period, there were two separate orbit-adjust maneuvers on one of the TDRSS spacecraft (TDRS-East) and one small orbit-adjust maneuver for Landsat-4. Independent assessments were made of the consistencies (overlap comparisons for the batch case and covariances and the first measurement residuals for the sequential case) of solutions produced by the batch and sequential methods. The forward-filtered RTOD/E orbit solutions were compared with the definitive GTDS orbit solutions for Landsat-4; the solution differences were generally less than 30 meters after the filter had reached steady state.

  6. Comparison of ERBS orbit determination accuracy using batch least-squares and sequential methods

    NASA Technical Reports Server (NTRS)

    Oza, D. H.; Jones, T. L.; Fabien, S. M.; Mistretta, G. D.; Hart, R. C.; Doll, C. E.

    1991-01-01

    The Flight Dynamics Div. (FDD) at NASA-Goddard commissioned a study to develop the Real Time Orbit Determination/Enhanced (RTOD/E) system as a prototype system for sequential orbit determination of spacecraft on a DOS based personal computer (PC). An overview is presented of RTOD/E capabilities and the results are presented of a study to compare the orbit determination accuracy for a Tracking and Data Relay Satellite System (TDRSS) user spacecraft obtained using RTOS/E on a PC with the accuracy of an established batch least squares system, the Goddard Trajectory Determination System (GTDS), operating on a mainframe computer. RTOD/E was used to perform sequential orbit determination for the Earth Radiation Budget Satellite (ERBS), and the Goddard Trajectory Determination System (GTDS) was used to perform the batch least squares orbit determination. The estimated ERBS ephemerides were obtained for the Aug. 16 to 22, 1989, timeframe, during which intensive TDRSS tracking data for ERBS were available. Independent assessments were made to examine the consistencies of results obtained by the batch and sequential methods. Comparisons were made between the forward filtered RTOD/E orbit solutions and definitive GTDS orbit solutions for ERBS; the solution differences were less than 40 meters after the filter had reached steady state.

  7. Sequential Estimation of Terrestrial Reference Frame using Information Filter for a Singular System

    NASA Astrophysics Data System (ADS)

    Chin, T. M.; Wu, X.; Gross, R. S.; Heflin, M. B.; Abbondanza, C.; Parker, J. W.

    2013-12-01

    At present, the solution of the International Terrestrial Reference Frame (ITRF) is computed through direct inversion of a single large-scale normal equation. The merits of performing the inversion by an alternative, sequential computational method include: (i) shorter computation time, and (ii) flexibility to incorporate empirical stochastic models for station motion and time-dependent noise processes. KALREF, an ITRF-like formulation implemented using the Kalman filter and a newly developed formulas for the RTS smoother, has been shown to be able to perform a significant portion of the computation sequentially in time. In this presentation, we present a sequential algorithm based on the "information filter", a well-documented variant of the Kalman filter. Unlike the standard Kalman filter, the information filter is able to handle under-constrained state variables and is hence particularly suitable for the "long-term solution" stage of ITRF, where the normal equation remains rank-deficient until an appropriate amount of data is collected ("stacked") over time. However, the ITRF "internal/intrinsic constraint" applied to the Helmert transformation parameters leads to a singularity in temporal dynamics, requiring some significant modifications in the filtering algorithm to avoid numerical degeneracy. We will present such developments in computational algorithms as well as evaluation of their numerical performances using actual data.

  8. Biological effects of fulvestrant on estrogen receptor positive human breast cancer: short, medium and long‐term effects based on sequential biopsies

    PubMed Central

    Robertson, John F.R.; Cheung, Kwok L.; Gutteridge, Eleanor; Ellis, Ian O.; Nicholson, Robert I.

    2015-01-01

    We report the first study of the biological effect of fulvestrant on ER positive clinical breast cancer using sequential biopsies through to progression. Thirty‐two locally/systemically advanced breast cancers treated with first‐line fulvestrant (250 mg/month) were biopsied at therapy initiation, 6 weeks, 6 months and progression and immunohistochemically‐analyzed for Ki67, ER, EGFR and HER2 expression/signaling activity. This series showed good fulvestrant responses (duration of response [DoR] = 25.8 months; clinical benefit = 81%). Ki67 fell (p < 0.001) in 79% of tumours by 6 months and lower Ki67 at all preprogression time‐points predicted for longer DoR. ER and PR significantly decreased in all tumours by 6 months (p < 0.001), with some declines in ER (serine 118) phosphorylation and Bcl‐2 (p = 0.007). There were modest HER2 increases (p = 0.034, 29% tumours) and loss of any detectable EGFR phosphorylation (p = 0.024, 50% tumours) and MAP kinase (ERK1/2) phosphorylation (p = 0.019, 65% tumours) by 6 months. While ER remained low, there was some recovery of Ki67, Bcl‐2 and (weakly) EGFR/MAPK activity in 45–67% patients at progression. Fulvestrant's anti‐proliferative impact is related to DoR, but while commonly downregulating ER and indicators of its signaling and depleting EGFR/MAPK signaling in some patients, additional elements must determine response duration. Residual ER at fulvestrant relapse explains reported sensitivity to further endocrine therapies. Occasional modest treatment‐induced HER2 and weakly detectable EGFR/HER2/MAPK signaling at relapse suggests targeting of such activity might have value alongside fulvestrant in some patients. However, unknown pathways must drive relapse in most. Ki67 has biomarker potential to predict fulvestrant outcome and as a quantitative measure of response. PMID:26178788

  9. Optimizing legacy molecular dynamics software with directive-based offload

    SciTech Connect

    Michael Brown, W.; Carrillo, Jan-Michael Y.; Gavhane, Nitin; Thakkar, Foram M.; Plimpton, Steven J.

    2015-05-14

    The directive-based programming models are one solution for exploiting many-core coprocessors to increase simulation rates in molecular dynamics. They offer the potential to reduce code complexity with offload models that can selectively target computations to run on the CPU, the coprocessor, or both. In our paper, we describe modifications to the LAMMPS molecular dynamics code to enable concurrent calculations on a CPU and coprocessor. We also demonstrate that standard molecular dynamics algorithms can run efficiently on both the CPU and an x86-based coprocessor using the same subroutines. As a consequence, we demonstrate that code optimizations for the coprocessor also result in speedups on the CPU; in extreme cases up to 4.7X. We provide results for LAMMAS benchmarks and for production molecular dynamics simulations using the Stampede hybrid supercomputer with both Intel (R) Xeon Phi (TM) coprocessors and NVIDIA GPUs: The optimizations presented have increased simulation rates by over 2X for organic molecules and over 7X for liquid crystals on Stampede. The optimizations are available as part of the "Intel package" supplied with LAMMPS. (C) 2015 Elsevier B.V. All rights reserved.

  10. Optimizing legacy molecular dynamics software with directive-based offload

    DOE PAGESBeta

    Michael Brown, W.; Carrillo, Jan-Michael Y.; Gavhane, Nitin; Thakkar, Foram M.; Plimpton, Steven J.

    2015-05-14

    The directive-based programming models are one solution for exploiting many-core coprocessors to increase simulation rates in molecular dynamics. They offer the potential to reduce code complexity with offload models that can selectively target computations to run on the CPU, the coprocessor, or both. In our paper, we describe modifications to the LAMMPS molecular dynamics code to enable concurrent calculations on a CPU and coprocessor. We also demonstrate that standard molecular dynamics algorithms can run efficiently on both the CPU and an x86-based coprocessor using the same subroutines. As a consequence, we demonstrate that code optimizations for the coprocessor also resultmore » in speedups on the CPU; in extreme cases up to 4.7X. We provide results for LAMMAS benchmarks and for production molecular dynamics simulations using the Stampede hybrid supercomputer with both Intel (R) Xeon Phi (TM) coprocessors and NVIDIA GPUs: The optimizations presented have increased simulation rates by over 2X for organic molecules and over 7X for liquid crystals on Stampede. The optimizations are available as part of the "Intel package" supplied with LAMMPS. (C) 2015 Elsevier B.V. All rights reserved.« less

  11. Droplet-based microfluidics and the dynamics of emulsions

    NASA Astrophysics Data System (ADS)

    Baret, Jean-Christophe; Brosseau, Quentin; Semin, Benoit; Qu, Xiaopeng

    2012-02-01

    Emulsions are complex fluids already involved for a long time in a wide-range of industrial processes, such as, for example, food, cosmetics or materials synthesis [1]. More recently, applications of emulsions have been extended to new fields like biotechnology or biochemistry where the compartmentalization of compounds in emulsion droplets is used to parallelise (bio-) chemical reactions [2]. Interestingly, these applications pinpoint to fundamental questions dealing with surfactant dynamics, dynamic surface tension, hydrodynamic interactions and electrohydrodynamics. Droplet-based microfluidics is a very powerful tool to quantitatively study the dynamics of emulsions at the single droplet level or even at the single interface level: well-controlled emulsions are produced and manipulated using hydrodynamics, electrical forces, optical actuation and combination of these effects. We will describe here how droplet-based microfluidics is used to extract quantitative informations on the physical-chemistry of emulsions for a better understanding and control of the dynamics of these systems [3].[4pt] [1] J. Bibette et al. Rep. Prog. Phys., 62, 969-1033 (1999)[0pt] [2] A. Theberge et al., Angewandte Chemie Int. Ed. 49, 5846 (2010)[0pt] [3] J.-C. Baret et al., Langmuir, 25, 6088 (2009)

  12. Optimizing legacy molecular dynamics software with directive-based offload

    NASA Astrophysics Data System (ADS)

    Michael Brown, W.; Carrillo, Jan-Michael Y.; Gavhane, Nitin; Thakkar, Foram M.; Plimpton, Steven J.

    2015-10-01

    Directive-based programming models are one solution for exploiting many-core coprocessors to increase simulation rates in molecular dynamics. They offer the potential to reduce code complexity with offload models that can selectively target computations to run on the CPU, the coprocessor, or both. In this paper, we describe modifications to the LAMMPS molecular dynamics code to enable concurrent calculations on a CPU and coprocessor. We demonstrate that standard molecular dynamics algorithms can run efficiently on both the CPU and an x86-based coprocessor using the same subroutines. As a consequence, we demonstrate that code optimizations for the coprocessor also result in speedups on the CPU; in extreme cases up to 4.7X. We provide results for LAMMPS benchmarks and for production molecular dynamics simulations using the Stampede hybrid supercomputer with both Intel®  Xeon Phi™ coprocessors and NVIDIA GPUs. The optimizations presented have increased simulation rates by over 2X for organic molecules and over 7X for liquid crystals on Stampede. The optimizations are available as part of the "Intel package" supplied with LAMMPS.

  13. Rumor diffusion in an interests-based dynamic social network.

    PubMed

    Tang, Mingsheng; Mao, Xinjun; Guessoum, Zahia; Zhou, Huiping

    2013-01-01

    To research rumor diffusion in social friend network, based on interests, a dynamic friend network is proposed, which has the characteristics of clustering and community, and a diffusion model is also proposed. With this friend network and rumor diffusion model, based on the zombie-city model, some simulation experiments to analyze the characteristics of rumor diffusion in social friend networks have been conducted. The results show some interesting observations: (1) positive information may evolve to become a rumor through the diffusion process that people may modify the information by word of mouth; (2) with the same average degree, a random social network has a smaller clustering coefficient and is more beneficial for rumor diffusion than the dynamic friend network; (3) a rumor is spread more widely in a social network with a smaller global clustering coefficient than in a social network with a larger global clustering coefficient; and (4) a network with a smaller clustering coefficient has a larger efficiency. PMID:24453911

  14. Rumor Diffusion in an Interests-Based Dynamic Social Network

    PubMed Central

    Mao, Xinjun; Guessoum, Zahia; Zhou, Huiping

    2013-01-01

    To research rumor diffusion in social friend network, based on interests, a dynamic friend network is proposed, which has the characteristics of clustering and community, and a diffusion model is also proposed. With this friend network and rumor diffusion model, based on the zombie-city model, some simulation experiments to analyze the characteristics of rumor diffusion in social friend networks have been conducted. The results show some interesting observations: (1) positive information may evolve to become a rumor through the diffusion process that people may modify the information by word of mouth; (2) with the same average degree, a random social network has a smaller clustering coefficient and is more beneficial for rumor diffusion than the dynamic friend network; (3) a rumor is spread more widely in a social network with a smaller global clustering coefficient than in a social network with a larger global clustering coefficient; and (4) a network with a smaller clustering coefficient has a larger efficiency. PMID:24453911

  15. Ultrafast dynamics in DNA base pairs following ultraviolet excitation.

    NASA Astrophysics Data System (ADS)

    Orr-Ewing, Andrew

    2015-03-01

    Photo-protective mechanisms in DNA are essential to maintain the integrity of the genetic code by preventing damage from absorption of solar ultraviolet (UV) radiation. We have used time-resolved infra-red (TRIR) spectroscopy to observe the dynamics of Watson-Crick nucleobase pairs following absorption of femtosecond UV laser pulses. The base pairs are prepared as nucleosides in solution, and photo-induced dynamics are probed in the carbonyl and N-H bond stretching regions using broadband IR pulses with picosecond time resolution. Results will be presented for the guanine-cytosine (G-C) base pair, contrasting the rapid recovery of ground-state products (the photo-protection pathway) with formation of other photoproducts which might represent photo-damage mechanisms. This work is a collaboration with the group of Prof F. Temps (Christian-Albrechts-Universitat zu Kiel). This research is supported by ERC Advanced Grant 290966 CAPRI.

  16. Tensor-based dictionary learning for dynamic tomographic reconstruction

    NASA Astrophysics Data System (ADS)

    Tan, Shengqi; Zhang, Yanbo; Wang, Ge; Mou, Xuanqin; Cao, Guohua; Wu, Zhifang; Yu, Hengyong

    2015-04-01

    In dynamic computed tomography (CT) reconstruction, the data acquisition speed limits the spatio-temporal resolution. Recently, compressed sensing theory has been instrumental in improving CT reconstruction from far few-view projections. In this paper, we present an adaptive method to train a tensor-based spatio-temporal dictionary for sparse representation of an image sequence during the reconstruction process. The correlations among atoms and across phases are considered to capture the characteristics of an object. The reconstruction problem is solved by the alternating direction method of multipliers. To recover fine or sharp structures such as edges, the nonlocal total variation is incorporated into the algorithmic framework. Preclinical examples including a sheep lung perfusion study and a dynamic mouse cardiac imaging demonstrate that the proposed approach outperforms the vectorized dictionary-based CT reconstruction in the case of few-view reconstruction.

  17. Percolation-based precursors of transitions in dynamical systems

    NASA Astrophysics Data System (ADS)

    Rodriguez Mendez, Victor Manuel; Eguiluz, Victor M.; Ramasco, Jose J.; Hernandez-Garcia, Emilio

    2015-04-01

    Transitions in complex dynamical systems are ubiquitous in nature. Finding leading indicators in such systems is a fundamental task in many areas of science, such as financial markets, the extinction of species or climate change studies. Here we propose a new framework to study systems close to a bifurcation point by analyzing topological properties, based on clusters and percolation, of functional networks defined from the time series. The use of networks allows us for a global parametrization of the system going far beyond simple two-point relations (classical correlations). The generality and versatility of the cluster-based method to forecast transitions is shown in two different kinds of data. In one hand, three theoretical dynamical systems displaying very different transitions and crossovers were used as a test bed. On the other hand, we have used the field of surface air temperature in the NINO 3.4 zone. In this new approach, critical transitions are identified before they occur.

  18. Tensor-based Dictionary Learning for Dynamic Tomographic Reconstruction

    PubMed Central

    Tan, Shengqi; Zhang, Yanbo; Wang, Ge; Mou, Xuanqin; Cao, Guohua; Wu, Zhifang; Yu, Hengyong

    2015-01-01

    In dynamic computed tomography (CT) reconstruction, the data acquisition speed limits the spatio-temporal resolution. Recently, compressed sensing theory has been instrumental in improving CT reconstruction from far few-view projections. In this paper, we present an adaptive method to train a tensor-based spatio-temporal dictionary for sparse representation of an image sequence during the reconstruction process. The correlations among atoms and across phases are considered to capture the characteristics of an object. The reconstruction problem is solved by the alternating direction method of multipliers. To recover fine or sharp structures such as edges, the nonlocal total variation is incorporated into the algorithmic framework. Preclinical examples including a sheep lung perfusion study and a dynamic mouse cardiac imaging demonstrate that the proposed approach outperforms the vectorized dictionary-based CT reconstruction in the case of few-view reconstruction. PMID:25779991

  19. Multiplexed protein profiling by sequential affinity capture.

    PubMed

    Ayoglu, Burcu; Birgersson, Elin; Mezger, Anja; Nilsson, Mats; Uhlén, Mathias; Nilsson, Peter; Schwenk, Jochen M

    2016-04-01

    Antibody microarrays enable parallelized and miniaturized analysis of clinical samples, and have proven to provide novel insights for the analysis of different proteomes. However, there are concerns that the performance of such direct labeling and single antibody assays are prone to off-target binding due to the sample context. To improve selectivity and sensitivity while maintaining the possibility to conduct multiplexed protein profiling, we developed a multiplexed and semi-automated sequential capture assay. This novel bead-based procedure encompasses a first antigen capture, labeling of captured protein targets on magnetic particles, combinatorial target elution and a read-out by a secondary capture bead array. We demonstrate in a proof-of-concept setting that target detection via two sequential affinity interactions reduced off-target contribution, while lowered background and noise levels, improved correlation to clinical values compared to single binder assays. We also compared sensitivity levels with single binder and classical sandwich assays, explored the possibility for DNA-based signal amplification, and demonstrate the applicability of the dual capture bead-based antibody microarray for biomarker analysis. Hence, the described concept enhances the possibilities for antibody array assays to be utilized for protein profiling in body fluids and beyond. PMID:26935855

  20. Modeling of Magma Dynamics Based on Two-Fluid Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Perepechko, Y. V.; Sorokin, K.

    2012-12-01

    Multi-velocity multi-porous models are often used as a hydrodynamic basis to describe dynamics of fluid-magma systems. These models cover such problems as fast acoustic processes or large-scaled dynamics of magma systems having non-compressible magma. Nonlinear dynamics of magma as multiphase compressible medium has not been studied sufficiently. In this work we study nonlinear thermodynamically consistent two-liquid model of magma system dynamics, based on conservation law method. The model is restricted by short times of local heat balance between phases. Pressure balance between phases is absent. Two-fluid magma model have various rheological properties of the composing phases: viscous liquid and viscoelastic Maxwell medium. The dynamics of magna flows have been studied for two types of magma systems: magma channels and intraplate intermediate magma chambers. Numerical problem of the dynamics for such media is solved using the control volume method ensuring physical correctness of the solution. The solutions are successfully verified for benchmark one-velocity models. In this work we give the results of numerical modeling using CVM for a number of non-stationary problems of nonlinear liquid filtering through granulated medium in magma channels and problems two-liquid system convection in intraplate magma chambers for various parameters. In the last case the convection regimes vary depending on non-dimensional Rayleigh and Darcy numbers and the parameter field, where compressibility effects appear, is located. The given model can be used as a hydrodynamic basis to model the evolution of magma, fluid-magma systems to study thermo-acoustic influence on hydrodynamic flows in such systems. This work was financially supported by the Russian Foundation for Basic Research, Grant #12-05-00625.

  1. Nonequilibrium structure in sequential assembly

    NASA Astrophysics Data System (ADS)

    Popov, Alexander V.; Craven, Galen T.; Hernandez, Rigoberto

    2015-11-01

    The assembly of monomeric constituents into molecular superstructures through sequential-arrival processes has been simulated and theoretically characterized. When the energetic interactions allow for complete overlap of the particles, the model is equivalent to that of the sequential absorption of soft particles on a surface. In the present work, we consider more general cases by including arbitrary aggregating geometries and varying prescriptions of the connectivity network. The resulting theory accounts for the evolution and final-state configurations through a system of equations governing structural generation. We find that particle geometries differ significantly from those in equilibrium. In particular, variations of structural rigidity and morphology tune particle energetics and result in significant variation in the nonequilibrium distributions of the assembly in comparison to the corresponding equilibrium case.

  2. Jamming transitions in force-based models for pedestrian dynamics.

    PubMed

    Chraibi, Mohcine; Ezaki, Takahiro; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin

    2015-10-01

    Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in the form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a force-based model which produces realistic jam dynamics without the appearance of unrealistic negative speeds for empirical desired walking speeds. PMID:26565291

  3. Jamming transitions in force-based models for pedestrian dynamics

    NASA Astrophysics Data System (ADS)

    Chraibi, Mohcine; Ezaki, Takahiro; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin

    2015-10-01

    Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in the form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a force-based model which produces realistic jam dynamics without the appearance of unrealistic negative speeds for empirical desired walking speeds.

  4. Blocking for Sequential Political Experiments

    PubMed Central

    Moore, Sally A.

    2013-01-01

    In typical political experiments, researchers randomize a set of households, precincts, or individuals to treatments all at once, and characteristics of all units are known at the time of randomization. However, in many other experiments, subjects “trickle in” to be randomized to treatment conditions, usually via complete randomization. To take advantage of the rich background data that researchers often have (but underutilize) in these experiments, we develop methods that use continuous covariates to assign treatments sequentially. We build on biased coin and minimization procedures for discrete covariates and demonstrate that our methods outperform complete randomization, producing better covariate balance in simulated data. We then describe how we selected and deployed a sequential blocking method in a clinical trial and demonstrate the advantages of our having done so. Further, we show how that method would have performed in two larger sequential political trials. Finally, we compare causal effect estimates from differences in means, augmented inverse propensity weighted estimators, and randomization test inversion. PMID:24143061

  5. Molecular Dynamics and Energy Minimization Based on Embedded Atom Method

    Energy Science and Technology Software Center (ESTSC)

    1995-03-01

    This program performs atomic scale computer simulations of the structure and dynamics of metallic system using energetices based on the Embedded Atom Method. The program performs two types of calculations. First, it performs local energy minimization of all atomic positions to determine ground state and saddle point energies and structures. Second, it performs molecular dynamics simulations to determine thermodynamics or miscroscopic dynamics of the system. In both cases, various constraints can be applied to themore » system. The volume of the system can be varied automatically to achieve any desired external pressure. The temperature in molecular dynamics simulations can be controlled by a variety of methods. Further, the temperature control can be applied either to the entire system or just a subset of the atoms that would act as a thermal source/sink. The motion of one or more of the atoms can be constrained to either simulate the effects of bulk boundary conditions or to facilitate the determination of saddle point configurations. The simulations are performed with periodic boundary conditions.« less

  6. Analysis of filter tuning techniques for sequential orbit determination

    NASA Technical Reports Server (NTRS)

    Lee, T.; Yee, C.; Oza, D.

    1995-01-01

    This paper examines filter tuning techniques for a sequential orbit determination (OD) covariance analysis. Recently, there has been a renewed interest in sequential OD, primarily due to the successful flight qualification of the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) using Doppler data extracted onboard the Extreme Ultraviolet Explorer (EUVE) spacecraft. TONS computes highly accurate orbit solutions onboard the spacecraft in realtime using a sequential filter. As the result of the successful TONS-EUVE flight qualification experiment, the Earth Observing System (EOS) AM-1 Project has selected TONS as the prime navigation system. In addition, sequential OD methods can be used successfully for ground OD. Whether data are processed onboard or on the ground, a sequential OD procedure is generally favored over a batch technique when a realtime automated OD system is desired. Recently, OD covariance analyses were performed for the TONS-EUVE and TONS-EOS missions using the sequential processing options of the Orbit Determination Error Analysis System (ODEAS). ODEAS is the primary covariance analysis system used by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD). The results of these analyses revealed a high sensitivity of the OD solutions to the state process noise filter tuning parameters. The covariance analysis results show that the state estimate error contributions from measurement-related error sources, especially those due to the random noise and satellite-to-satellite ionospheric refraction correction errors, increase rapidly as the state process noise increases. These results prompted an in-depth investigation of the role of the filter tuning parameters in sequential OD covariance analysis. This paper analyzes how the spacecraft state estimate errors due to dynamic and measurement-related error sources are affected by the process noise level used. This information is then used to establish

  7. Process-based Principles for Restoring Dynamic River Ecosystems

    NASA Astrophysics Data System (ADS)

    Pess, G. R.; Beechie, T. J.; Pollock, M. M.

    2006-12-01

    Process-based restoration focuses on re-establishing natural rates and magnitudes of geomorphological, hydrological, and biological processes that sustain biodiversity and biological productivity in dynamic river ecosystems. It contrasts with traditional restoration practices, which focus on creating specific habitat characteristics that meet perceived "good" or "minimum" habitat conditions or standards. Process-based restoration relies on the understanding that habitat-forming processes are dynamic and comprise a shifting mosaic of diverse habitats. Local animal populations or communities are adapted to this dynamic habitat mosaic. Fundamental principles underlying process-based restoration are: (1) restoration must address biophysical processes that drive ecosystem change, and (2) the scale of restoration must be relevant to the appropriate landscape and biological process scales. Restoration efforts that re-establish natural rates and magnitudes of system processes promote ecosystem recovery, and help avoid common pitfalls of traditional restoration practices such as creating habitats that are outside the range of a site's natural potential, fixing habitats in space and time, and building habitats that are ultimately overwhelmed by untreated or uncontrollable system drivers. Restoring such processes also allows dynamic riverine ecosystems to express their natural potential, which generates the natural range of habitat conditions to which biological communities are adapted. Non-point processes such as erosion often require restoration at the scale of watersheds to effectively restore river ecosystems, whereas reach-level processes such as the maintenance of connected floodplain habitats can be effective at smaller spatial scales. Flow restoration in regulated rivers should consider the full range of environmentally important flows (e.g., low flow to floods). Biological processes such as the life-history scales of migratory animals (e.g., anadromous salmon) may be

  8. Sequential estimation and satellite data assimilation in meteorology and oceanography

    NASA Technical Reports Server (NTRS)

    Ghil, M.

    1986-01-01

    The role of dynamics in estimating the state of the atmosphere and ocean from incomplete and noisy data is discussed and the classical applications of four-dimensional data assimilation to large-scale atmospheric dynamics are presented. It is concluded that sequential updating of a forecast model with continuously incoming conventional and remote-sensing data is the most natural way of extracting the maximum amount of information from the imperfectly known dynamics, on the one hand, and the inaccurate and incomplete observations, on the other.

  9. Inverse sequential simulation: Performance and implementation details

    NASA Astrophysics Data System (ADS)

    Xu, Teng; Gómez-Hernández, J. Jaime

    2015-12-01

    For good groundwater flow and solute transport numerical modeling, it is important to characterize the formation properties. In this paper, we analyze the performance and important implementation details of a new approach for stochastic inverse modeling called inverse sequential simulation (iSS). This approach is capable of characterizing conductivity fields with heterogeneity patterns difficult to capture by standard multiGaussian-based inverse approaches. The method is based on the multivariate sequential simulation principle, but the covariances and cross-covariances used to compute the local conditional probability distributions are computed by simple co-kriging which are derived from an ensemble of conductivity and piezometric head fields, in a similar manner as the experimental covariances are computed in an ensemble Kalman filtering. A sensitivity analysis is performed on a synthetic aquifer regarding the number of members of the ensemble of realizations, the number of conditioning data, the number of piezometers at which piezometric heads are observed, and the number of nodes retained within the search neighborhood at the moment of computing the local conditional probabilities. The results show the importance of having a sufficiently large number of all of the mentioned parameters for the algorithm to characterize properly hydraulic conductivity fields with clear non-multiGaussian features.

  10. The Sequential Probability Ratio Test and Binary Item Response Models

    ERIC Educational Resources Information Center

    Nydick, Steven W.

    2014-01-01

    The sequential probability ratio test (SPRT) is a common method for terminating item response theory (IRT)-based adaptive classification tests. To decide whether a classification test should stop, the SPRT compares a simple log-likelihood ratio, based on the classification bound separating two categories, to prespecified critical values. As has…

  11. Reduced bases for nonlinear structural dynamic systems: A comparative study

    NASA Astrophysics Data System (ADS)

    Lülf, Fritz Adrian; Tran, Duc-Minh; Ohayon, Roger

    2013-07-01

    The presented work provides an overview of some commonly used approaches for generating reduced bases for discrete nonlinear dynamic systems. It investigates the performance and the robustness of these bases if they are applied in a reduction-by-projection procedure on different test cases. The bases are created from the Linear Normal Modes, the Ritz-vectors, the Proper and the Smooth Orthogonal Decomposition method, the A Priori Reduction, the Centroidal Voronoi Tessellation and the Local Equivalent Linear Stiffness Method. Second-Order Terms and an Enhanced Proper Orthogonal Decomposition formulation are included as variants. The test cases are small dimensional, locally or entirely nonlinear system subjected to a harmonic or an impulse force excitation. The double objective of this numerical study is, first, to determine which bases are most adequate for a given combination of nonlinearity and excitation and, second, to which extend the bases exhibit an inherent robustness if the parameterisation of the excitation is changed. A specific multicriteria decision analysis score is developed to assess the bases' performance. As a major result, a strong dependence of the performance of the bases on the type of excitation is established and thus some bases become more adequate for a certain situation than others. Also a lack of robustness for all considered bases can be observed. This situation improves in most cases if the basis is generated with the most critical values of the parameter.

  12. MME-based attitude dynamics identification and estimation for SAMPEX

    NASA Astrophysics Data System (ADS)

    Depena, Juan; Crassidis, John L.; McPartland, Michael D.; Meyer, Thomas J.; Mook, D. Joseph

    1994-05-01

    A method is described for obtaining optimal attitude estimation algorithms for spacecraft lacking attitude rate measurement devices (rate gyros), and then demonstrated using actual flight data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. SAMPEX does not have on-board rate sensing, and relies on sun sensors and a three-axis magnetometer for attitude determination. Problems arise since typical attitude estimation is accomplished by filtering measurements of both attitude and attitude rates. Rates are nearly always sampled much more densely than are attitudes. Thus, the absence/loss of rate data normally reduces both the total amount of data available and the sampling density (in time) by a substantial fraction. As a result, the sensitivity of the estimates to model uncertainty and to measurement noise increases. In order to maintain accuracy in the attitude estimates, there is increased need for accurate models of the rotational dynamics. The proposed approach is based on the minimum model error (MME) optimal estimation strategy, which has been successfully applied to estimation of poorly modeled dynamic systems which are relatively sparsely and/or noisily measured. The MME estimates may be used to construct accurate models of the system dynamics (i.e. perform system model identification). Thus, an MME-based approach directly addresses the problems created by absence of attitude rate measurements.

  13. Available Instruments for Analyzing Molecular Dynamics Trajectories

    PubMed Central

    Likhachev, I. V.; Balabaev, N. K.; Galzitskaya, O. V.

    2016-01-01

    Molecular dynamics trajectories are the result of molecular dynamics simulations. Trajectories are sequential snapshots of simulated molecular system which represents atomic coordinates at specific time periods. Based on the definition, in a text format trajectory files are characterized by their simplicity and uselessness. To obtain information from such files, special programs and information processing techniques are applied: from molecular dynamics animation to finding characteristics along the trajectory (versus time). In this review, we describe different programs for processing molecular dynamics trajectories. The performance of these programs, usefulness for analyses of molecular dynamics trajectories, strong and weak aspects are discussed. PMID:27053964

  14. A Dynamic Attitude Measurement System Based on LINS

    PubMed Central

    Li, Hanzhou; Pan, Quan; Wang, Xiaoxu; Zhang, Juanni; Li, Jiang; Jiang, Xiangjun

    2014-01-01

    A dynamic attitude measurement system (DAMS) is developed based on a laser inertial navigation system (LINS). Three factors of the dynamic attitude measurement error using LINS are analyzed: dynamic error, time synchronization and phase lag. An optimal coning errors compensation algorithm is used to reduce coning errors, and two-axis wobbling verification experiments are presented in the paper. The tests indicate that the attitude accuracy is improved 2-fold by the algorithm. In order to decrease coning errors further, the attitude updating frequency is improved from 200 Hz to 2000 Hz. At the same time, a novel finite impulse response (FIR) filter with three notches is designed to filter the dither frequency of the ring laser gyro (RLG). The comparison tests suggest that the new filter is five times more effective than the old one. The paper indicates that phase-frequency characteristics of FIR filter and first-order holder of navigation computer constitute the main sources of phase lag in LINS. A formula to calculate the LINS attitude phase lag is introduced in the paper. The expressions of dynamic attitude errors induced by phase lag are derived. The paper proposes a novel synchronization mechanism that is able to simultaneously solve the problems of dynamic test synchronization and phase compensation. A single-axis turntable and a laser interferometer are applied to verify the synchronization mechanism. The experiments results show that the theoretically calculated values of phase lag and attitude error induced by phase lag can both match perfectly with testing data. The block diagram of DAMS and physical photos are presented in the paper. The final experiments demonstrate that the real-time attitude measurement accuracy of DAMS can reach up to 20″ (1σ) and the synchronization error is less than 0.2 ms on the condition of three axes wobbling for 10 min. PMID:25177802

  15. A dynamic attitude measurement system based on LINS.

    PubMed

    Li, Hanzhou; Pan, Quan; Wang, Xiaoxu; Zhang, Juanni; Li, Jiang; Jiang, Xiangjun

    2014-01-01

    A dynamic attitude measurement system (DAMS) is developed based on a laser inertial navigation system (LINS). Three factors of the dynamic attitude measurement error using LINS are analyzed: dynamic error, time synchronization and phase lag. An optimal coning errors compensation algorithm is used to reduce coning errors, and two-axis wobbling verification experiments are presented in the paper. The tests indicate that the attitude accuracy is improved 2-fold by the algorithm. In order to decrease coning errors further, the attitude updating frequency is improved from 200 Hz to 2000 Hz. At the same time, a novel finite impulse response (FIR) filter with three notches is designed to filter the dither frequency of the ring laser gyro (RLG). The comparison tests suggest that the new filter is five times more effective than the old one. The paper indicates that phase-frequency characteristics of FIR filter and first-order holder of navigation computer constitute the main sources of phase lag in LINS. A formula to calculate the LINS attitude phase lag is introduced in the paper. The expressions of dynamic attitude errors induced by phase lag are derived. The paper proposes a novel synchronization mechanism that is able to simultaneously solve the problems of dynamic test synchronization and phase compensation. A single-axis turntable and a laser interferometer are applied to verify the synchronization mechanism. The experiments results show that the theoretically calculated values of phase lag and attitude error induced by phase lag can both match perfectly with testing data. The block diagram of DAMS and physical photos are presented in the paper. The final experiments demonstrate that the real-time attitude measurement accuracy of DAMS can reach up to 20″ (1σ) and the synchronization error is less than 0.2 ms on the condition of three axes wobbling for 10 min. PMID:25177802

  16. Dynamic Network-Based Epistasis Analysis: Boolean Examples

    PubMed Central

    Azpeitia, Eugenio; Benítez, Mariana; Padilla-Longoria, Pablo; Espinosa-Soto, Carlos; Alvarez-Buylla, Elena R.

    2011-01-01

    In this article we focus on how the hierarchical and single-path assumptions of epistasis analysis can bias the inference of gene regulatory networks. Here we emphasize the critical importance of dynamic analyses, and specifically illustrate the use of Boolean network models. Epistasis in a broad sense refers to gene interactions, however, as originally proposed by Bateson, epistasis is defined as the blocking of a particular allelic effect due to the effect of another allele at a different locus (herein, classical epistasis). Classical epistasis analysis has proven powerful and useful, allowing researchers to infer and assign directionality to gene interactions. As larger data sets are becoming available, the analysis of classical epistasis is being complemented with computer science tools and system biology approaches. We show that when the hierarchical and single-path assumptions are not met in classical epistasis analysis, the access to relevant information and the correct inference of gene interaction topologies is hindered, and it becomes necessary to consider the temporal dynamics of gene interactions. The use of dynamical networks can overcome these limitations. We particularly focus on the use of Boolean networks that, like classical epistasis analysis, relies on logical formalisms, and hence can complement classical epistasis analysis and relax its assumptions. We develop a couple of theoretical examples and analyze them from a dynamic Boolean network model perspective. Boolean networks could help to guide additional experiments and discern among alternative regulatory schemes that would be impossible or difficult to infer without the elimination of these assumption from the classical epistasis analysis. We also use examples from the literature to show how a Boolean network-based approach has resolved ambiguities and guided epistasis analysis. Our article complements previous accounts, not only by focusing on the implications of the hierarchical and

  17. First Principles Dynamics of Photoexcited DNA and RNA Bases

    SciTech Connect

    Hudock, Hanneli R.; Levine, Benjamin G.; Thompson, Alexis L.; Martinez, Todd J.

    2007-12-26

    The reaction dynamics of excited electronic states in nucleic acid bases is a key process in DNA photodamage. Recent ultrafast spectroscopy experiments have shown multi-component decays of excited uracil and thymine, tentatively assigned to nonadiabatic transitions involving multiple electronic states. Using both quantum chemistry and first principles quantum molecular dynamics methods we show that a true minimum on the bright S{sub 2} electronic state is responsible for the first step which occurs on a femtosecond timescale. Thus the observed femtosecond decay does not correspond to surface crossing as previously thought. We suggest that subsequent barrier crossing to the minimal energy S{sub 2}/S{sub 1} conical intersection is responsible for the picosecond decay.

  18. Voronoi Diagram Based Optimization of Dynamic Reactive Power Sources

    SciTech Connect

    Huang, Weihong; Sun, Kai; Qi, Junjian; Xu, Yan

    2015-01-01

    Dynamic var sources can effectively mitigate fault-induced delayed voltage recovery (FIDVR) issues or even voltage collapse. This paper proposes a new approach to optimization of the sizes of dynamic var sources at candidate locations by a Voronoi diagram based algorithm. It first disperses sample points of potential solutions in a searching space, evaluates a cost function at each point by barycentric interpolation for the subspaces around the point, and then constructs a Voronoi diagram about cost function values over the entire space. Accordingly, the final optimal solution can be obtained. Case studies on the WSCC 9-bus system and NPCC 140-bus system have validated that the new approach can quickly identify the boundary of feasible solutions in searching space and converge to the global optimal solution.

  19. Opinion dynamics in a group-based society

    NASA Astrophysics Data System (ADS)

    Gargiulo, F.; Huet, S.

    2010-09-01

    Many models have been proposed to analyze the evolution of opinion structure due to the interaction of individuals in their social environment. Such models analyze the spreading of ideas both in completely interacting backgrounds and on social networks, where each person has a finite set of interlocutors. In this paper we analyze the reciprocal feedback between the opinions of the individuals and the structure of the interpersonal relationships at the level of community structures. For this purpose we define a group-based random network and we study how this structure co-evolves with opinion dynamics processes. We observe that the adaptive network structure affects the opinion dynamics process helping the consensus formation. The results also show interesting behaviors in regards to the size distribution of the groups and their correlation with opinion structure.

  20. Dynamic Mechanical Behavior of Boron Carbide Based Composites

    NASA Astrophysics Data System (ADS)

    Hayun, S.; Frage, N.; Dariel, M. P.; Zaretsky, E.

    2007-12-01

    The dynamic response of two boron carbide-based composites was studied in planar impact experiments (impact velocities 100-1000 m/sec) using a 25 mm gas gun. The composites were fabricated by infiltration of compacted B4C and partially sintered B4C preforms by molten Si. In the course of the infiltration process, the liquid silicon reacts with the B4C phase resulting in the formation of the SiC and B12(B,C,Si)3 phases along with some residual silicon present in the infiltrated composites. The velocities of the sample-PMMA window interface were monitored continuously by VISAR. The composites display a relatively high HEL (12-14 GPa) and spall strength (about 1 GPa) values. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to characterize the fracture surface. The correlation between the microstructure of the infiltrated composites and their dynamic response is discussed.

  1. Dynamic positioning system based on active disturbance rejection technology

    NASA Astrophysics Data System (ADS)

    Lei, Zhengling; Guo, Chen; Fan, Yunsheng

    2015-08-01

    A dynamically positioned vessel, by the International Maritime Organization (IMO) and the certifying class societies (DNV, ABS, LR, etc.), is defined as a vessel that maintains its position and heading (fixed location or pre-determined track) exclusively by means of active thrusters. The development of control technology promotes the upgrading of dynamic positioning (DP) systems. Today there are two different DP systems solutions available on the market: DP system based on PID regulator and that based on model-based control. Both systems have limited disturbance rejection capability due to their design principle. In this paper, a new DP system solution is proposed based on Active Disturbance Rejection Control (ADRC) technology. This technology is composed of Tracking-Differentiator (TD), Extended State Observer (ESO) and Nonlinear Feedback Combination. On one hand, both TD and ESO can act as filters and can be used in place of conventional filters; on the other hand, the total disturbance of the system can be estimated and compensated by ESO, which therefore enhances the system's disturbance rejection capability. This technology's advantages over other methods lie in two aspects: 1) This method itself can not only achieve control objectives but also filter noisy measurements without other specialized filters; 2) This method offers a new useful approach to suppress the ocean disturbance. The simulation results demonstrate the effectiveness of the proposed method.

  2. Susceptibility-Based Analysis Of Dynamic Gadolinium Bolus Perfusion MRI

    PubMed Central

    Bonekamp, David; Barker, Peter B.; Leigh, Richard; van Zijl, Peter C.M.; Li, Xu

    2014-01-01

    Purpose An algorithm is developed for the reconstruction of dynamic, gadolinium (Gd) bolus MR perfusion images of the human brain, based on quantitative susceptibility mapping (QSM). Methods The method is evaluated in 5 perfusion scans obtained from 4 different patients scanned at 3T, and compared to the conventional analysis based on changes in the transverse relaxation rate ΔR2* and to theoretical predictions. QSM images were referenced to ventricular CSF for each dynamic of the perfusion sequence. Results Images of cerebral blood flow and blood volume were successfully reconstructed from the QSM-analysis, and were comparable to those reconstructed using ΔR2*. The magnitudes of the Gd-associated susceptibility effects in gray and white matter were consistent with theoretical predictions. Conclusion QSM-based analysis may have some theoretical advantages compared to ΔR2*, including a simpler relationship between signal change and Gd concentration. However, disadvantages are its much lower contrast-to-noise ratio, artifacts due to respiration and other effects, and more complicated reconstruction methods. More work is required to optimize data acquisition protocols for QSM-based perfusion imaging. PMID:24604343

  3. A Bayesian sequential processor approach to spectroscopic portal system decisions

    SciTech Connect

    Sale, K; Candy, J; Breitfeller, E; Guidry, B; Manatt, D; Gosnell, T; Chambers, D

    2007-07-31

    The development of faster more reliable techniques to detect radioactive contraband in a portal type scenario is an extremely important problem especially in this era of constant terrorist threats. Towards this goal the development of a model-based, Bayesian sequential data processor for the detection problem is discussed. In the sequential processor each datum (detector energy deposit and pulse arrival time) is used to update the posterior probability distribution over the space of model parameters. The nature of the sequential processor approach is that a detection is produced as soon as it is statistically justified by the data rather than waiting for a fixed counting interval before any analysis is performed. In this paper the Bayesian model-based approach, physics and signal processing models and decision functions are discussed along with the first results of our research.

  4. Monte Carlo-based simulation of dynamic jaws tomotherapy

    SciTech Connect

    Sterpin, E.; Chen, Y.; Chen, Q.; Lu, W.; Mackie, T. R.; Vynckier, S.

    2011-09-15

    Purpose: Original TomoTherapy systems may involve a trade-off between conformity and treatment speed, the user being limited to three slice widths (1.0, 2.5, and 5.0 cm). This could be overcome by allowing the jaws to define arbitrary fields, including very small slice widths (<1 cm), which are challenging for a beam model. The aim of this work was to incorporate the dynamic jaws feature into a Monte Carlo (MC) model called TomoPen, based on the MC code PENELOPE, previously validated for the original TomoTherapy system. Methods: To keep the general structure of TomoPen and its efficiency, the simulation strategy introduces several techniques: (1) weight modifiers to account for any jaw settings using only the 5 cm phase-space file; (2) a simplified MC based model called FastStatic to compute the modifiers faster than pure MC; (3) actual simulation of dynamic jaws. Weight modifiers computed with both FastStatic and pure MC were compared. Dynamic jaws simulations were compared with the convolution/superposition (C/S) of TomoTherapy in the ''cheese'' phantom for a plan with two targets longitudinally separated by a gap of 3 cm. Optimization was performed in two modes: asymmetric jaws-constant couch speed (''running start stop,'' RSS) and symmetric jaws-variable couch speed (''symmetric running start stop,'' SRSS). Measurements with EDR2 films were also performed for RSS for the formal validation of TomoPen with dynamic jaws. Results: Weight modifiers computed with FastStatic were equivalent to pure MC within statistical uncertainties (0.5% for three standard deviations). Excellent agreement was achieved between TomoPen and C/S for both asymmetric jaw opening/constant couch speed and symmetric jaw opening/variable couch speed, with deviations well within 2%/2 mm. For RSS procedure, agreement between C/S and measurements was within 2%/2 mm for 95% of the points and 3%/3 mm for 98% of the points, where dose is greater than 30% of the prescription dose (gamma analysis

  5. Physics of base-pairing dynamics in DNA

    NASA Astrophysics Data System (ADS)

    Manghi, Manoel; Destainville, Nicolas

    2016-05-01

    As a key molecule of life, Deoxyribo-Nucleic Acid (DNA) is the focus of numbers of investigations with the help of biological, chemical and physical techniques. From a physical point of view, both experimental and theoretical works have brought quantitative insights into DNA base-pairing dynamics that we review in this Report, putting emphasis on theoretical developments. We discuss the dynamics at the base-pair scale and its pivotal coupling with the polymer one, with a polymerization index running from a few nucleotides to tens of kilo-bases. This includes opening and closure of short hairpins and oligomers as well as zipping and unwinding of long macromolecules. We review how different physical mechanisms are either used by Nature or utilized in biotechnological processes to separate the two intertwined DNA strands, by insisting on quantitative results. They go from thermally-assisted denaturation bubble nucleation to force- or torque-driven mechanisms. We show that the helical character of the molecule, possibly supercoiled, can play a key role in many denaturation and renaturation processes. We categorize the mechanisms according to the relative timescales associated with base-pairing and chain orientational degrees of freedom such as bending and torsional elastic ones. In some specific situations, these chain orientational degrees of freedom can be integrated out, and the quasi-static approximation is valid. The complex dynamics then reduces to the diffusion in a low-dimensional free-energy landscape. In contrast, some important cases of experimental interest necessarily appeal to far-from-equilibrium statistical mechanics and hydrodynamics.

  6. Quantification of cardiorespiratory interactions based on joint symbolic dynamics.

    PubMed

    Kabir, Muammar M; Saint, David A; Nalivaiko, Eugene; Abbott, Derek; Voss, Andreas; Baumert, Mathias

    2011-10-01

    Cardiac and respiratory rhythms are highly nonlinear and nonstationary. As a result traditional time-domain techniques are often inadequate to characterize their complex dynamics. In this article, we introduce a novel technique to investigate the interactions between R-R intervals and respiratory phases based on their joint symbolic dynamics. To evaluate the technique, electrocardiograms (ECG) and respiratory signals were recorded in 13 healthy subjects in different body postures during spontaneous and controlled breathing. Herein, the R-R time series were extracted from ECG and respiratory phases were obtained from abdomen impedance belts using the Hilbert transform. Both time series were transformed into ternary symbol vectors based on the changes between two successive R-R intervals or respiratory phases. Subsequently, words of different symbol lengths were formed and the correspondence between the two series of words was determined to quantify the interaction between cardiac and respiratory cycles. To validate our results, respiratory sinus arrhythmia (RSA) was further studied using the phase-averaged characterization of the RSA pattern. The percentage of similarity of the sequence of symbols, between the respective words of the two series determined by joint symbolic dynamics, was significantly reduced in the upright position compared to the supine position (26.4 ± 4.7 vs. 20.5 ± 5.4%, p < 0.01). Similarly, RSA was also reduced during upright posture, but the difference was less significant (0.11 ± 0.02 vs. 0.08 ± 0.01 s, p < 0.05). In conclusion, joint symbolic dynamics provides a new efficient technique for the analysis of cardiorespiratory interaction that is highly sensitive to the effects of orthostatic challenge. PMID:21618043

  7. A Sequential Monte Carlo Approach for Streamflow Forecasting

    NASA Astrophysics Data System (ADS)

    Hsu, K.; Sorooshian, S.

    2008-12-01

    As alternatives to traditional physically-based models, Artificial Neural Network (ANN) models offer some advantages with respect to the flexibility of not requiring the precise quantitative mechanism of the process and the ability to train themselves from the data directly. In this study, an ANN model was used to generate one-day-ahead streamflow forecasts from the precipitation input over a catchment. Meanwhile, the ANN model parameters were trained using a Sequential Monte Carlo (SMC) approach, namely Regularized Particle Filter (RPF). The SMC approaches are known for their capabilities in tracking the states and parameters of a nonlinear dynamic process based on the Baye's rule and the proposed effective sampling and resampling strategies. In this study, five years of daily rainfall and streamflow measurement were used for model training. Variable sample sizes of RPF, from 200 to 2000, were tested. The results show that, after 1000 RPF samples, the simulation statistics, in terms of correlation coefficient, root mean square error, and bias, were stabilized. It is also shown that the forecasted daily flows fit the observations very well, with the correlation coefficient of higher than 0.95. The results of RPF simulations were also compared with those from the popular back-propagation ANN training approach. The pros and cons of using SMC approach and the traditional back-propagation approach will be discussed.

  8. On trajectory-based nonadiabatic dynamics: Bohmian dynamics versus trajectory surface hopping

    NASA Astrophysics Data System (ADS)

    Curchod, Basile F. E.; Tavernelli, Ivano

    2013-05-01

    In this work, we present a complete derivation of the NonAdiabatic Bohmian DYnamics (NABDY) equations of motion. This approach naturally emerges from a transformation of the molecular time-dependent Schrödinger equation in the adiabatic representation of the electronic states. The numerical implementation of the method is discussed while simple nonadiabatic models are employed to address the accuracy of NABDY and to reveal its ability to capture nuclear quantum effects that are missed in trajectory surface hopping (TSH) due to the independent trajectory approximation. A careful comparison of the correlated, NABDY, and the uncorrelated, TSH, propagation is also given together with a description of the main approximations and assumptions underlying the "derivation" of a nonadiabatic molecular dynamics scheme based on classical trajectories.

  9. Extended follow-up of the CYCLOFA-LUNE trial comparing two sequential induction and maintenance treatment regimens for proliferative lupus nephritis based either on cyclophosphamide or on cyclosporine A.

    PubMed

    Závada, J; Sinikka Pesicková, S; Rysavá, R; Horák, P; Hrncír, Z; Lukác, J; Rovensky, J; Vítová, J; Havrda, M; Rychlík, I; Böhmova, J; Vlasáková, V; Slatinská, J; Zadrazil, J; Olejárová, M; Tegzova, D; Tesar, V

    2014-01-01

    Objective To evaluate the extended follow-up of the CYCLOFA-LUNE trial, a randomized prospective trial comparing two sequential induction and maintenance treatment regimens for proliferative lupus nephritis based either on cyclophosphamide (CPH) or cyclosporine A (CyA). Patients and methods Data for kidney function and adverse events were collected by a cross-sectional survey for 38 of 40 patients initially randomized in the CYCLOFA-LUNE trial. Results The median follow-up time was 7.7 years (range 5.0-10.3). Rates of renal impairment and end-stage renal disease, adverse events (death, cardiovascular event, tumor, premature menopause) did not differ between the CPH and CyA group, nor did mean serum creatinine, 24 h proteinuria and SLICC damage score at last follow-up. Most patients in both groups were still treated with glucocorticoids, other immunosuppressant agents and blood pressure lowering drugs. Conclusion An immunosuppressive regimen based on CyA achieved similar clinical results to that based on CPH in the very long term. PMID:24213308

  10. A Bayesian Theory of Sequential Causal Learning and Abstract Transfer.

    PubMed

    Lu, Hongjing; Rojas, Randall R; Beckers, Tom; Yuille, Alan L

    2016-03-01

    Two key research issues in the field of causal learning are how people acquire causal knowledge when observing data that are presented sequentially, and the level of abstraction at which learning takes place. Does sequential causal learning solely involve the acquisition of specific cause-effect links, or do learners also acquire knowledge about abstract causal constraints? Recent empirical studies have revealed that experience with one set of causal cues can dramatically alter subsequent learning and performance with entirely different cues, suggesting that learning involves abstract transfer, and such transfer effects involve sequential presentation of distinct sets of causal cues. It has been demonstrated that pre-training (or even post-training) can modulate classic causal learning phenomena such as forward and backward blocking. To account for these effects, we propose a Bayesian theory of sequential causal learning. The theory assumes that humans are able to consider and use several alternative causal generative models, each instantiating a different causal integration rule. Model selection is used to decide which integration rule to use in a given learning environment in order to infer causal knowledge from sequential data. Detailed computer simulations demonstrate that humans rely on the abstract characteristics of outcome variables (e.g., binary vs. continuous) to select a causal integration rule, which in turn alters causal learning in a variety of blocking and overshadowing paradigms. When the nature of the outcome variable is ambiguous, humans select the model that yields the best fit with the recent environment, and then apply it to subsequent learning tasks. Based on sequential patterns of cue-outcome co-occurrence, the theory can account for a range of phenomena in sequential causal learning, including various blocking effects, primacy effects in some experimental conditions, and apparently abstract transfer of causal knowledge. PMID:25902728

  11. Process tomography via sequential measurements on a single quantum system

    NASA Astrophysics Data System (ADS)

    Bassa, Humairah; Goyal, Sandeep K.; Choudhary, Sujit K.; Uys, Hermann; Diósi, Lajos; Konrad, Thomas

    2015-09-01

    We utilize a discrete (sequential) measurement protocol to investigate quantum process tomography of a single two-level quantum system, with an unknown initial state, undergoing Rabi oscillations. The ignorance of the dynamical parameters is encoded into a continuous-variable classical system which is coupled to the two-level quantum system via a generalized Hamiltonian. This combined estimate of the quantum state and dynamical parameters is updated by using the information obtained from sequential measurements on the quantum system and, after a sufficient waiting period, faithful state monitoring and parameter determination is obtained. Numerical evidence is used to demonstrate the convergence of the state estimate to the true state of the hybrid system.

  12. Gradient-based adaptation of continuous dynamic model structures

    NASA Astrophysics Data System (ADS)

    La Cava, William G.; Danai, Kourosh

    2016-01-01

    A gradient-based method of symbolic adaptation is introduced for a class of continuous dynamic models. The proposed model structure adaptation method starts with the first-principles model of the system and adapts its structure after adjusting its individual components in symbolic form. A key contribution of this work is its introduction of the model's parameter sensitivity as the measure of symbolic changes to the model. This measure, which is essential to defining the structural sensitivity of the model, not only accommodates algebraic evaluation of candidate models in lieu of more computationally expensive simulation-based evaluation, but also makes possible the implementation of gradient-based optimisation in symbolic adaptation. The proposed method is applied to models of several virtual and real-world systems that demonstrate its potential utility.

  13. Sequential ranging: How it works

    NASA Technical Reports Server (NTRS)

    Baugh, Harold W.

    1993-01-01

    This publication is directed to the users of data from the Sequential Ranging Assembly (SRA), and to others who have a general interest in range measurements. It covers the hardware, the software, and the processes used in acquiring range data; it does not cover analytical aspects such as the theory of modulation, detection, noise spectral density, and other highly technical subjects. In other words, it covers how ranging is done, but not the details of why it works. The publication also includes an appendix that gives a brief discussion of PN ranging, a capability now under development.

  14. A high speed sequential decoder

    NASA Technical Reports Server (NTRS)

    Lum, H., Jr.

    1972-01-01

    The performance and theory of operation for the High Speed Hard Decision Sequential Decoder are delineated. The decoder is a forward error correction system which is capable of accepting data from binary-phase-shift-keyed and quadriphase-shift-keyed modems at input data rates up to 30 megabits per second. Test results show that the decoder is capable of maintaining a composite error rate of 0.00001 at an input E sub b/N sub o of 5.6 db. This performance has been obtained with minimum circuit complexity.

  15. Random sequential adsorption on fractals

    NASA Astrophysics Data System (ADS)

    Ciesla, Michal; Barbasz, Jakub

    2012-07-01

    Irreversible adsorption of spheres on flat collectors having dimension d < 2 is studied. Molecules are adsorbed on Sierpinski's triangle and carpet-like fractals (1 < d < 2), and on general Cantor set (d < 1). Adsorption process is modeled numerically using random sequential adsorption (RSA) algorithm. The paper concentrates on measurement of fundamental properties of coverages, i.e., maximal random coverage ratio and density autocorrelation function, as well as RSA kinetics. Obtained results allow to improve phenomenological relation between maximal random coverage ratio and collector dimension. Moreover, simulations show that, in general, most of known dimensional properties of adsorbed monolayers are valid for non-integer dimensions.

  16. Random sequential adsorption of tetramers

    NASA Astrophysics Data System (ADS)

    Cieśla, Michał

    2013-07-01

    Adsorption of a tetramer built of four identical spheres was studied numerically using the random sequential adsorption (RSA) algorithm. Tetramers were adsorbed on a two-dimensional, flat and homogeneous surface. Two different models of the adsorbate were investigated: a rhomboid and a square one; monomer centres were put on vertices of rhomboids and squares, respectively. Numerical simulations allow us to establish the maximal random coverage ratio as well as the available surface function (ASF), which is crucial for determining kinetics of the adsorption process. These results were compared with data obtained experimentally for KfrA plasmid adsorption. Additionally, the density autocorrelation function was measured.

  17. Random sequential adsorption on fractals.

    PubMed

    Ciesla, Michal; Barbasz, Jakub

    2012-07-28

    Irreversible adsorption of spheres on flat collectors having dimension d < 2 is studied. Molecules are adsorbed on Sierpinski's triangle and carpet-like fractals (1 < d < 2), and on general Cantor set (d < 1). Adsorption process is modeled numerically using random sequential adsorption (RSA) algorithm. The paper concentrates on measurement of fundamental properties of coverages, i.e., maximal random coverage ratio and density autocorrelation function, as well as RSA kinetics. Obtained results allow to improve phenomenological relation between maximal random coverage ratio and collector dimension. Moreover, simulations show that, in general, most of known dimensional properties of adsorbed monolayers are valid for non-integer dimensions. PMID:22852643

  18. A thorough investigation of the progressive reset dynamics in HfO{sub 2}-based resistive switching structures

    SciTech Connect

    Lorenzi, P. Rao, R.; Irrera, F.; Suñé, J.; Miranda, E.

    2015-09-14

    According to previous reports, filamentary electron transport in resistive switching HfO{sub 2}-based metal-insulator-metal structures can be modeled using a diode-like conduction mechanism with a series resistance. Taking the appropriate limits, the model allows simulating the high (HRS) and low (LRS) resistance states of the devices in terms of exponential and linear current-voltage relationships, respectively. In this letter, we show that this simple equivalent circuit approach can be extended to represent the progressive reset transition between the LRS and HRS if a generalized logistic growth model for the pre-exponential diode current factor is considered. In this regard, it is demonstrated here that a Verhulst logistic model does not provide accurate results. The reset dynamics is interpreted as the sequential deactivation of multiple conduction channels spanning the dielectric film. Fitting results for the current-voltage characteristics indicate that the voltage sweep rate only affects the deactivation rate of the filaments without altering the main features of the switching dynamics.

  19. Self-consistency based control scheme for magnetization dynamics

    SciTech Connect

    Albuquerque, G.; Miltat, J.; Thiaville, A.

    2001-06-01

    A numerical framework is presented for the solution of the Landau{endash}Lifshitz{endash}Gilbert equation of magnetization motion using a semi-implicit Crank{endash}Nicholson integration scheme. Along with the details of both space and time domain discretizations, we report on the development of a physically based self-consistency criterion that allows for a quantitative measurement of error in dynamic micromagnetic simulations. In essence, this criterion relies in recalculating from actual magnetization motion the imposed phenomenological damping constant. Test calculations were performed with special attention paid to the determination of suitable integration time steps. {copyright} 2001 American Institute of Physics.

  20. Dynamically adjustable annular laser trapping based on axicons

    SciTech Connect

    Shao, Bing; Esener, Sadik C.; Nascimento, Jaclyn M.; Botvinick, Elliot L.; Berns, Michael W

    2006-09-01

    To study the chemotactic response of sperm to an egg and to characterize sperm motility, an annular laser trap based on axicons is designed, simulated with the ray-tracing tool, and implemented. The diameter of the trapping ring can be adjusted dynamically for a range of over 400 {mu}m by simply translating one axicon along the optical axis. Trapping experiments with microspheres and dog sperm demonstrate the feasibility of the system,and the power requirement agrees with theoretical expectation. This new type of laser trapping could provide a prototype of a parallel, objective, and quantitative tool for animal fertility and biotropism study.

  1. An immunity-based model for dynamic distributed intrusion detection

    NASA Astrophysics Data System (ADS)

    Qiao, Peili; Wang, Tong; Su, Jie

    2008-03-01

    The traditional intrusion detection systems mostly adopt the analysis engine of the concentrating type, so the misinformation rate is higher and lack of self-adaptability, which is already difficult to meet increasing extensive security demand of the distributed network environment. An immunity-based model combining immune theory, data mining and data fusion technique for dynamic distributed intrusion detection is proposed in this paper. This system presents the method of establishing and evolving the set of early gene, and defines the sets of Self, Nonself and Immunity cells. Moreover, a detailed description is given to the architecture and work mechanism of the model, and the characters of the model are analyzed.

  2. Anharmonic densities of states: A general dynamics-based solution.

    PubMed

    Jellinek, Julius; Aleinikava, Darya

    2016-06-01

    Density of states is a fundamental physical characteristic that lies at the foundation of statistical mechanics and theoretical constructs that derive from them (e.g., kinetic rate theories, phase diagrams, and others). Even though most real physical systems are anharmonic, the vibrational density of states is customarily treated within the harmonic approximation, or with some partial, often limited, account for anharmonicity. The reason for this is that the problem of anharmonic densities of states stubbornly resisted a general and exact, yet convenient and straightforward in applications, solution. Here we formulate such a solution within both classical and quantum mechanics. It is based on actual dynamical behavior of systems as a function of energy and as observed, or monitored, on a chosen time scale, short or long. As a consequence, the resulting anharmonic densities of states are fully dynamically informed and, in general, time-dependent. As such, they lay the ground for formulation of new statistical mechanical frameworks that incorporate time and are ergodic, by construction, with respect to actual dynamical behavior of systems. PMID:27276941

  3. Anharmonic densities of states: A general dynamics-based solution

    NASA Astrophysics Data System (ADS)

    Jellinek, Julius; Aleinikava, Darya

    2016-06-01

    Density of states is a fundamental physical characteristic that lies at the foundation of statistical mechanics and theoretical constructs that derive from them (e.g., kinetic rate theories, phase diagrams, and others). Even though most real physical systems are anharmonic, the vibrational density of states is customarily treated within the harmonic approximation, or with some partial, often limited, account for anharmonicity. The reason for this is that the problem of anharmonic densities of states stubbornly resisted a general and exact, yet convenient and straightforward in applications, solution. Here we formulate such a solution within both classical and quantum mechanics. It is based on actual dynamical behavior of systems as a function of energy and as observed, or monitored, on a chosen time scale, short or long. As a consequence, the resulting anharmonic densities of states are fully dynamically informed and, in general, time-dependent. As such, they lay the ground for formulation of new statistical mechanical frameworks that incorporate time and are ergodic, by construction, with respect to actual dynamical behavior of systems.

  4. Algorithm for Stabilizing a POD-Based Dynamical System

    NASA Technical Reports Server (NTRS)

    Kalb, Virginia L.

    2010-01-01

    This algorithm provides a new way to improve the accuracy and asymptotic behavior of a low-dimensional system based on the proper orthogonal decomposition (POD). Given a data set representing the evolution of a system of partial differential equations (PDEs), such as the Navier-Stokes equations for incompressible flow, one may obtain a low-dimensional model in the form of ordinary differential equations (ODEs) that should model the dynamics of the flow. Temporal sampling of the direct numerical simulation of the PDEs produces a spatial time series. The POD extracts the temporal and spatial eigenfunctions of this data set. Truncated to retain only the most energetic modes followed by Galerkin projection of these modes onto the PDEs obtains a dynamical system of ordinary differential equations for the time-dependent behavior of the flow. In practice, the steps leading to this system of ODEs entail numerically computing first-order derivatives of the mean data field and the eigenfunctions, and the computation of many inner products. This is far from a perfect process, and often results in the lack of long-term stability of the system and incorrect asymptotic behavior of the model. This algorithm describes a new stabilization method that utilizes the temporal eigenfunctions to derive correction terms for the coefficients of the dynamical system to significantly reduce these errors.

  5. Osmosis-Based Pressure Generation: Dynamics and Application

    PubMed Central

    Li, Suyi; Billeh, Yazan N.; Wang, K. W.; Mayer, Michael

    2014-01-01

    This paper describes osmotically-driven pressure generation in a membrane-bound compartment while taking into account volume expansion, solute dilution, surface area to volume ratio, membrane hydraulic permeability, and changes in osmotic gradient, bulk modulus, and degree of membrane fouling. The emphasis lies on the dynamics of pressure generation; these dynamics have not previously been described in detail. Experimental results are compared to and supported by numerical simulations, which we make accessible as an open source tool. This approach reveals unintuitive results about the quantitative dependence of the speed of pressure generation on the relevant and interdependent parameters that will be encountered in most osmotically-driven pressure generators. For instance, restricting the volume expansion of a compartment allows it to generate its first 5 kPa of pressure seven times faster than without a restraint. In addition, this dynamics study shows that plants are near-ideal osmotic pressure generators, as they are composed of many small compartments with large surface area to volume ratios and strong cell wall reinforcements. Finally, we demonstrate two applications of an osmosis-based pressure generator: actuation of a soft robot and continuous volume delivery over long periods of time. Both applications do not need an external power source but rather take advantage of the energy released upon watering the pressure generators. PMID:24614529

  6. Dynamic mechanical behavior of boron carbide-based composites

    NASA Astrophysics Data System (ADS)

    Hayun, Shmulik; Frage, Nahum; Dariel, Moshe; Zaretsky, Eugene

    2007-06-01

    This presentation is concerned with the dynamic response of two types of boron carbide-based composites. The composites were fabricated by infiltration of compacted but unsintered B4C preforms and of partially sintered B4C skeletons by liquid Si. During the infiltration process, molten silicon reacts with the B4C phase resulting in the formation of the SiC and B12(B,C,Si)3 phases. Some residual silicon is also present in the infiltrated composites. The dynamic behavior was studied in planar impact experiments (impact velocities 100-1000 m/sec) using a 25 mm gas gun. The velocities of the sample-PMMA window interface were monitored continuously by VISAR. The composites failed completely in compression, at loads above their HEL (17-18 GPa). The spall strength, deduced from low-velocity impacts, ranged from 0.5 to 1.1 GPa, depending on the tensile strain rate. Scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) were used to analyze the fracture surface. The correlation between the microstructure of the infiltrated composites and their dynamic response is discussed.

  7. Dynamic Chest Image Analysis: Model-Based Perfusion Analysis in Dynamic Pulmonary Imaging

    NASA Astrophysics Data System (ADS)

    Liang, Jianming; Järvi, Timo; Kiuru, Aaro; Kormano, Martti; Svedström, Erkki

    2003-12-01

    The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion analysis. According to perfusion properties, we first devise a novel mathematical function to form a perfusion model. A simple yet accurate approach is further introduced to extract cardiac systolic and diastolic phases from the heart, so that this cardiac information may be utilized to accelerate the perfusion analysis and improve its sensitivity in detecting pulmonary perfusion abnormalities. This makes perfusion analysis not only fast but also robust in computation; consequently, perfusion analysis becomes computationally feasible without using contrast media. Our clinical case studies with 52 patients show that this technique is effective for pulmonary embolism even without using contrast media, demonstrating consistent correlations with computed tomography (CT) and nuclear medicine (NM) studies. This fluoroscopical examination takes only about 2 seconds for perfusion study with only low radiation dose to patient, involving no preparation, no radioactive isotopes, and no contrast media.

  8. RFID Student Educational Experiences at the UNT College of Engineering: A Sequential Approach to Creating a Project-Based RFID Course

    ERIC Educational Resources Information Center

    Vaidyanathan, V. V.; Varanasi, M. R.; Kougianos, E.; Wang, Shuping; Raman, H.

    2009-01-01

    This paper describes radio frequency identification (RFID) projects, designed and implemented by students in the College of Engineering at the University of North Texas, as part of their senior-design project requirement. The paper also describes an RFID-based project implemented at Rice Middle School in Plano, TX, which went on to win multiple…

  9. Delay test generation for synchronous sequential circuits

    NASA Astrophysics Data System (ADS)

    Devadas, Srinivas

    1989-05-01

    We address the problem of generating tests for delay faults in non-scan synchronous sequential circuits. Delay test generation for sequential circuits is a considerably more difficult problem than delay testing of combinational circuits and has received much less attention. In this paper, we present a method for generating test sequences to detect delay faults in sequential circuits using the stuck-at fault sequential test generator STALLION. The method is complete in that it will generate a delay test sequence for a targeted fault given sufficient CPU time, if such a sequence exists. We term faults for which no delay test sequence exists, under out test methodology, sequentially delay redundant. We describe means of eliminating sequential delay redundancies in logic circuits. We present a partial-scan methodology for enhancing the testability of difficult-to-test of untestable sequential circuits, wherein a small number of flip-flops are selected and made controllable/observable. The selection process guarantees the elimination of all sequential delay redundancies. We show that an intimate relationship exists between state assignment and delay testability of a sequential machine. We describe a state assignment algorithm for the synthesis of sequential machines with maximal delay fault testability. Preliminary experimental results using the test generation, partial-scan and synthesis algorithm are presented.

  10. A New Curb Detection Method for Unmanned Ground Vehicles Using 2D Sequential Laser Data

    PubMed Central

    Liu, Zhao; Wang, Jinling; Liu, Daxue

    2013-01-01

    Curb detection is an important research topic in environment perception, which is an essential part of unmanned ground vehicle (UGV) operations. In this paper, a new curb detection method using a 2D laser range finder in a semi-structured environment is presented. In the proposed method, firstly, a local Digital Elevation Map (DEM) is built using 2D sequential laser rangefinder data and vehicle state data in a dynamic environment and a probabilistic moving object deletion approach is proposed to cope with the effect of moving objects. Secondly, the curb candidate points are extracted based on the moving direction of the vehicle in the local DEM. Finally, the straight and curved curbs are detected by the Hough transform and the multi-model RANSAC algorithm, respectively. The proposed method can detect the curbs robustly in both static and typical dynamic environments. The proposed method has been verified in real vehicle experiments. PMID:23325170

  11. A new curb detection method for unmanned ground vehicles using 2D sequential laser data.

    PubMed

    Liu, Zhao; Wang, Jinling; Liu, Daxue

    2013-01-01

    Curb detection is an important research topic in environment perception, which is an essential part of unmanned ground vehicle (UGV) operations. In this paper, a new curb detection method using a 2D laser range finder in a semi-structured environment is presented. In the proposed method, firstly, a local Digital Elevation Map (DEM) is built using 2D sequential laser rangefinder data and vehicle state data in a dynamic environment and a probabilistic moving object deletion approach is proposed to cope with the effect of moving objects. Secondly, the curb candidate points are extracted based on the moving direction of the vehicle in the local DEM. Finally, the straight and curved curbs are detected by the Hough transform and the multi-model RANSAC algorithm, respectively. The proposed method can detect the curbs robustly in both static and typical dynamic environments. The proposed method has been verified in real vehicle experiments. PMID:23325170

  12. Mitral paravalvular leak closure by antegrade percutaneous approach: three-dimensional transesophageal echocardiographic guided multiple Amplatzer implantation by a modified sequential anchoring-based technique.

    PubMed

    Tarantini, Giuseppe; Mojoli, Marco; Napodano, Massimo

    2013-10-01

    We describe the technical aspects and the possible advantages of a modified anchoring-based technique for the implantation of multiple Amplatzer devices, in a case of large anteroseptal mitral paravalvular leak causing massive regurgitation, which was manaed by antegrade transseptal, single-stage, percutaneous approach. Real-time three-dimensional transesophageal echocardiographic guidance was crucial to ensure successful recrossings of the target defect and the optimal anatomical closure. PMID:23613380

  13. Sequentially evolved bilateral epidural haematomas.

    PubMed

    Rochat, P; Johannesen, H H; Poulsgård, L; Bøgeskov, L

    2002-12-01

    Sequentially evolved bilateral epidural haematomas, where the second haematoma evolves after surgical removal of the first haematoma, are rarely reported. We report two cases of this entity. One patient was involved in a road traffic accident and the other was suffering from a head injury after an assault. CT scans showed that both patients had an unilateral epidural haematoma with a thin presumably epidural haemorrhage on the opposite side. Both patients were operated for their epidural haematomas, but did not improve after surgical treatment, and postoperative CT scans revealed evolving of an epidural haematoma on the opposite side. After evacuation of the second epidural haematoma both patients recovered quickly. Sequentially evolved bilateral epidural haematomas are rare, but must be considered in the postoperative intensive care treatment in patients with epidural haematomas. Both cases emphasize the need for intensive care monitoring after an operation for an epidural haematoma and the need for CT scans if the patient does not improve quickly after removal of the haematoma. This is especially important if a small contralateral haematoma is seen on the initial CT scan. PMID:12445923

  14. Quantum estimation via sequential measurements

    NASA Astrophysics Data System (ADS)

    Burgarth, Daniel; Giovannetti, Vittorio; Kato, Airi N.; Yuasa, Kazuya

    2015-11-01

    The problem of estimating a parameter of a quantum system through a series of measurements performed sequentially on a quantum probe is analyzed in the general setting where the underlying statistics is explicitly non-i.i.d. We present a generalization of the central limit theorem in the present context, which under fairly general assumptions shows that as the number N of measurement data increases the probability distribution of functionals of the data (e.g., the average of the data) through which the target parameter is estimated becomes asymptotically normal and independent of the initial state of the probe. At variance with the previous studies (Guţă M 2011 Phys. Rev. A 83 062324; van Horssen M and Guţă M 2015 J. Math. Phys. 56 022109) we take a diagrammatic approach, which allows one to compute not only the leading orders in N of the moments of the average of the data but also those of the correlations among subsequent measurement outcomes. In particular our analysis points out that the latter, which are not available in usual i.i.d. data, can be exploited in order to improve the accuracy of the parameter estimation. An explicit application of our scheme is discussed by studying how the temperature of a thermal reservoir can be estimated via sequential measurements on a quantum probe in contact with the reservoir.

  15. Fluorescence sensor for sequential detection of zinc and phosphate ions.

    PubMed

    An, Miran; Kim, Bo-Yeon; Seo, Hansol; Helal, Aasif; Kim, Hong-Seok

    2016-12-01

    A new, highly selective turn-on fluorescent chemosensor based on 2-(2'-tosylamidophenyl)thiazole (1) for the detection of zinc and phosphate ions in ethanol was synthesized and characterized. Sensor 1 showed a high selectivity for zinc compared to other cations and sequentially detected hydrogen pyrophosphate and hydrogen phosphate. The fluorescence mechanism can be explained by two different mechanisms: (i) the inhibition of excited-state intramolecular proton transfer (ESIPT) and (ii) chelation-induced enhanced fluorescence by binding with Zn(2+). The sequential detection of phosphate anions was achieved by the quenching and subsequent revival of ESIPT. PMID:27343439

  16. Fluorescence sensor for sequential detection of zinc and phosphate ions

    NASA Astrophysics Data System (ADS)

    An, Miran; Kim, Bo-Yeon; Seo, Hansol; Helal, Aasif; Kim, Hong-Seok

    2016-12-01

    A new, highly selective turn-on fluorescent chemosensor based on 2-(2‧-tosylamidophenyl)thiazole (1) for the detection of zinc and phosphate ions in ethanol was synthesized and characterized. Sensor 1 showed a high selectivity for zinc compared to other cations and sequentially detected hydrogen pyrophosphate and hydrogen phosphate. The fluorescence mechanism can be explained by two different mechanisms: (i) the inhibition of excited-state intramolecular proton transfer (ESIPT) and (ii) chelation-induced enhanced fluorescence by binding with Zn2 +. The sequential detection of phosphate anions was achieved by the quenching and subsequent revival of ESIPT.

  17. Satellite-based Observation of Arctic River Dynamics

    NASA Astrophysics Data System (ADS)

    Overeem, I.; Brakenridge, R.; Hudson, B.

    2015-12-01

    One of the indicators of a warming Arctic region is an intensification of the hydrological cycle, with increasing permafrost and glacial melt and possibly more precipitation resulting in higher river runoff. Indeed, a significant increase of nearly 10% in annual river flux has been observed in 13 major rivers throughout the entire Arctic region over the last 30 years. However, direct measurements are extremely sparse for 100's of smaller-scale tundra river systems, as well as for proglacial rivers around the Greenland Ice Sheet margin. Observations at in-situ gauging stations are hampered by seasonal ice coverage, break-up and freeze-up dynamics, unstable banks, and difficult access. To overcome such difficulties, we develop remote-sensing based river discharge measurement techniques using a variety of satellite sensors, including reflectance in the near-infrared band of MODIS, LANDSAT, and brightness temperature from the passive microwave sensors AMSR-E and AMSR-2. We use varying inundation of the river channel and floodplain throughout a season to quantify the changing Arctic river flux. A new approach to detect river ice break up in spring has been developed, and is now undergoing validation. To calibrate the remote sensing signal to daily river discharge, we employ either in-situ short observation records, or a numerical distributed hydrological model driven by daily reanalysis climate data. Quantitative reconstructions of meltwater fluxes in rivers along the Greenland Ice Sheet margin obtained so far show a dampened response of these rivers to Greenland Ice Sheet melt. Techniques are now deployed to map river dynamics along the Chukchi Sea and Beaufort Sea coasts, and show shifts in break-up dynamics and flooding patterns. Once calibrated, satellite-based reconstructions have the potential to lengthen short observational records to a ~15 year timespan.

  18. Finding a Path for Segmentation Through Sequential Learning.

    PubMed

    Wang, Hongzhi; Cao, Yu; Syed-Mahmood, Tanveer F

    2015-01-01

    Sequential learning techniques, such as auto-context, that applies the output of an intermediate classifier as contextual features for its subsequent classifier has shown impressive performance for semantic segmentation. We show that these methods can be interpreted as an approximation technique derived from a Bayesian formulation. To improve the effectiveness of applying this approximation technique, we propose a new sequential learning approach for semantic segmentation that solves a segmentation problem by breaking it into a series of simplified segmentation problems. Sequentially solving each of the simplified problems along the path leads to a more effective way for solving the original segmentation problem. To achieve this goal, we also propose a learning-based method to generate simplified segmentation problems by explicitly controlling the complexities of the modeling classifiers. We report promising results on the 2013 SATA canine leg muscle segmentation dataset. PMID:26221697

  19. A dynamic bead-based microarray for parallel DNA detection

    NASA Astrophysics Data System (ADS)

    Sochol, R. D.; Casavant, B. P.; Dueck, M. E.; Lee, L. P.; Lin, L.

    2011-05-01

    A microfluidic system has been designed and constructed by means of micromachining processes to integrate both microfluidic mixing of mobile microbeads and hydrodynamic microbead arraying capabilities on a single chip to simultaneously detect multiple bio-molecules. The prototype system has four parallel reaction chambers, which include microchannels of 18 × 50 µm2 cross-sectional area and a microfluidic mixing section of 22 cm length. Parallel detection of multiple DNA oligonucleotide sequences was achieved via molecular beacon probes immobilized on polystyrene microbeads of 16 µm diameter. Experimental results show quantitative detection of three distinct DNA oligonucleotide sequences from the Hepatitis C viral (HCV) genome with single base-pair mismatch specificity. Our dynamic bead-based microarray offers an effective microfluidic platform to increase parallelization of reactions and improve microbead handling for various biological applications, including bio-molecule detection, medical diagnostics and drug screening.

  20. A network-based dynamical ranking system for competitive sports

    NASA Astrophysics Data System (ADS)

    Motegi, Shun; Masuda, Naoki

    2012-12-01

    From the viewpoint of networks, a ranking system for players or teams in sports is equivalent to a centrality measure for sports networks, whereby a directed link represents the result of a single game. Previously proposed network-based ranking systems are derived from static networks, i.e., aggregation of the results of games over time. However, the score of a player (or team) fluctuates over time. Defeating a renowned player in the peak performance is intuitively more rewarding than defeating the same player in other periods. To account for this factor, we propose a dynamic variant of such a network-based ranking system and apply it to professional men's tennis data. We derive a set of linear online update equations for the score of each player. The proposed ranking system predicts the outcome of the future games with a higher accuracy than the static counterparts.

  1. A network-based dynamical ranking system for competitive sports

    PubMed Central

    Motegi, Shun; Masuda, Naoki

    2012-01-01

    From the viewpoint of networks, a ranking system for players or teams in sports is equivalent to a centrality measure for sports networks, whereby a directed link represents the result of a single game. Previously proposed network-based ranking systems are derived from static networks, i.e., aggregation of the results of games over time. However, the score of a player (or team) fluctuates over time. Defeating a renowned player in the peak performance is intuitively more rewarding than defeating the same player in other periods. To account for this factor, we propose a dynamic variant of such a network-based ranking system and apply it to professional men's tennis data. We derive a set of linear online update equations for the score of each player. The proposed ranking system predicts the outcome of the future games with a higher accuracy than the static counterparts. PMID:23226590

  2. Knowledge-based zonal grid generation for computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Andrews, Alison E.

    1988-01-01

    Automation of flow field zoning in two dimensions is an important step towards reducing the difficulty of three-dimensional grid generation in computational fluid dynamics. Using a knowledge-based approach makes sense, but problems arise which are caused by aspects of zoning involving perception, lack of expert consensus, and design processes. These obstacles are overcome by means of a simple shape and configuration language, a tunable zoning archetype, and a method of assembling plans from selected, predefined subplans. A demonstration system for knowledge-based two-dimensional flow field zoning has been successfully implemented and tested on representative aerodynamic configurations. The results show that this approach can produce flow field zonings that are acceptable to experts with differing evaluation criteria.

  3. Dynamic mechanical characterization and modelling of polypropylene based organoclay nanocomposite

    NASA Astrophysics Data System (ADS)

    Wang, Kui; Matadi Boumbimba, Rodrigue; Bahlouli, Nadia; Ahzi, Said; Muller, René

    2015-09-01

    In order to investigate the dynamic behaviour of polypropylene based organoclay nanocomposite, the polypropylene matrix and a master batch of polypropylene modified anhydrid maleic were mixed by means of melt mixing technique. The experimental characterization was performed by using split Hopkinson pressure bars (SHPB), at different strain rates and temperatures. A significant increase of the yield stress of nanocomposite was shown with the present of organoclay, comparing to neat PP. A three-phase approach based on the micromechanical formulation of the cooperative model is proposed to model the yield behaviour of the polymer nanocomposite. Our proposed approach accounts for strain rate and temperature effects as well as the organoclay exfoliation effect. The predictions of models for the nanocomposite yield behaviour showed a good agreement with experimental data.

  4. High-dynamic range DMD-based IR scene projector

    NASA Astrophysics Data System (ADS)

    Dupuis, Julia R.; Mansur, David J.; Vaillancourt, Robert; Benedict-Gill, Ryan; Newbry, Scott P.

    2013-03-01

    OPTRA is developing a next-generation digital micromirror device (DMD) based two-band infrared scene projector (IRSP) with infinite bit-depth independent of frame rate and an order of magnitude improvement in contrast over the state of the art. Traditionally DMD-based IRSPs have offered larger format and superior uniformity and pixel operability relative to resistive and diode arrays, however, they have been limited in contrast and also by the inherent bitdepth / frame rate tradeoff imposed by pulse width modulation (PWM). OPTRA's high dynamic range IRSP (HIDRA SP) has broken this dependency with a dynamic structured illumination solution. The HIDRA SP uses a source conditioning DMD to impose the structured illumination on two projector DMDs - one for each spectral band. The source conditioning DMD is operated in binary mode, and the relay optics which form the structured illumination act as a low pass spatial filter. The structured illumination is therefore spatially grayscaled and more importantly is analog with no PWM. In addition, the structured illumination concentrates energy where bright object will be projected and extinguishes energy in dark regions; the result is a significant improvement in contrast. The projector DMDs are operated with 8-bit PWM, however the total projected image is analog with no bit-depth / frame rate dependency. In this paper we describe our progress towards the development, build, and test of a prototype HIDRA SP.

  5. High-dynamic range DMD-based infrared scene projector

    NASA Astrophysics Data System (ADS)

    Mansur, David J.; Vaillancourt, Robert; Benedict-Gill, Ryan; Newbry, Scott P.; Rentz Dupuis, Julia

    2013-05-01

    OPTRA is developing a next-generation digital micromirror device (DMD) based two-band infrared scene projector (IRSP) with infinite bit-depth independent of frame rate and an order of magnitude improvement in contrast over the state of the art. Traditionally DMD-based IRSPs have offered larger format and superior uniformity and pixel operability relative to resistive and diode arrays, however, they have been limited in contrast and also by the inherent bitdepth / frame rate tradeoff imposed by pulse width modulation (PWM). OPTRA's high dynamic range IRSP (HIDRA SP) has broken this dependency with a dynamic structured illumination solution. The HIDRA SP uses a source conditioning DMD to impose the structured illumination on two projector DMDs - one for each spectral band. The source conditioning DMD is operated in binary mode, and the relay optics which form the structured illumination act as a low pass spatial filter. The structured illumination is therefore spatially grayscaled and more importantly is analog with no PWM. In addition, the structured illumination concentrates energy where bright object will be projected and extinguishes energy in dark regions; the result is a significant improvement in contrast. The projector DMDs are operated with 8-bit PWM, however the total projected image is analog with no bit-depth / frame rate dependency. In this paper we describe our progress towards the development, build, and test of a prototype HIDRA SP.

  6. Transcriptome dynamics-based operon prediction in prokaryotes

    PubMed Central

    2014-01-01

    Background Inferring operon maps is crucial to understanding the regulatory networks of prokaryotic genomes. Recently, RNA-seq based transcriptome studies revealed that in many bacterial species the operon structure vary with the change of environmental conditions. Therefore, new computational solutions that use both static and dynamic data are necessary to create condition specific operon predictions. Results In this work, we propose a novel classification method that integrates RNA-seq based transcriptome profiles with genomic sequence features to accurately identify the operons that are expressed under a measured condition. The classifiers are trained on a small set of confirmed operons and then used to classify the remaining gene pairs of the organism studied. Finally, by linking consecutive gene pairs classified as operons, our computational approach produces condition-dependent operon maps. We evaluated our approach on various RNA-seq expression profiles of the bacteria Haemophilus somni, Porphyromonas gingivalis, Escherichia coli and Salmonella enterica. Our results demonstrate that, using features depending on both transcriptome dynamics and genome sequence characteristics, we can identify operon pairs with high accuracy. Moreover, the combination of DNA sequence and expression data results in more accurate predictions than each one alone. Conclusion We present a computational strategy for the comprehensive analysis of condition-dependent operon maps in prokaryotes. Our method can be used to generate condition specific operon maps of many bacterial organisms for which high-resolution transcriptome data is available. PMID:24884724

  7. Medical applications of model-based dynamic thermography

    NASA Astrophysics Data System (ADS)

    Nowakowski, Antoni; Kaczmarek, Mariusz; Ruminski, Jacek; Hryciuk, Marcin; Renkielska, Alicja; Grudzinski, Jacek; Siebert, Janusz; Jagielak, Dariusz; Rogowski, Jan; Roszak, Krzysztof; Stojek, Wojciech

    2001-03-01

    The proposal to use active thermography in medical diagnostics is promising in some applications concerning investigation of directly accessible parts of the human body. The combination of dynamic thermograms with thermal models of investigated structures gives attractive possibility to make internal structure reconstruction basing on different thermal properties of biological tissues. Measurements of temperature distribution synchronized with external light excitation allow registration of dynamic changes of local temperature dependent on heat exchange conditions. Preliminary results of active thermography applications in medicine are discussed. For skin and under- skin tissues an equivalent thermal model may be determined. For the assumed model its effective parameters may be reconstructed basing on the results of transient thermal processes. For known thermal diffusivity and conductivity of specific tissues the local thickness of a two or three layer structure may be calculated. Results of some medical cases as well as reference data of in vivo study on animals are presented. The method was also applied to evaluate the state of the human heart during the open chest cardio-surgical interventions. Reference studies of evoked heart infarct in pigs are referred, too. We see the proposed new in medical applications technique as a promising diagnostic tool. It is a fully non-invasive, clean, handy, fast and affordable method giving not only qualitative view of investigated surfaces but also an objective quantitative measurement result, accurate enough for many applications including fast screening of affected tissues.

  8. Identification of Cross-Linked Peptides after Click-Based Enrichment Using Sequential Collision-Induced Dissociation and Electron Transfer Dissociation Tandem Mass Spectrometry

    SciTech Connect

    Chowdhury, Saiful M.; Du, Xiuxia; Tolic, Nikola; Wu, Si; Moore, Ronald J.; Mayer, M. Uljana; Smith, Richard D.; Adkins, Joshua N.

    2009-07-01

    Chemical cross-linking combined with mass spectrometric analysis is emerging as a powerful technique for protein-protein interaction and protein structure elucidation studies.1 Cross-linkers covalently link two interacting proteins, often with chemistries specific to certain amino acid side chains. After enzymatic digestion of the proteins, the resulting cross-linked peptides can be subjected to analysis by LC-MS(/MS) to identify cross-linked species.2,3 For studying protein interactions using chemical cross-linking towards global discovery-based applications, the critical needs are the development of cross-linkers that are highly specific, amenable to LC-MS/MS, and resulting spectra are interpretable by bioinformatics tools to automatically assign cross-linked peptides with high confidence.4-10 As recently mentioned by Aebersold and co-workers, due to the low relative abundances of cross-linking products compared to their unmodified counterparts, enrichment of cross-linked species is also highly desirable to improve the likelihood of unambiguous identification of cross-linked peptides.6 Most of the currently available enrichable cross-linkers are bulky and are not amenable to studying protein-protein interactions in vivo. To discover protein-protein interactions with high confidence, there is a need for chemical cross-linkers that can effectively label protein complexes, utilize mass spectrometry based bottom-up proteomics analysis pipelines and also contains enrichment functionality.

  9. Approaches to Modelling the Dynamical Activity of Brain Function Based on the Electroencephalogram

    NASA Astrophysics Data System (ADS)

    Liley, David T. J.; Frascoli, Federico

    The brain is arguably the quintessential complex system as indicated by the patterns of behaviour it produces. Despite many decades of concentrated research efforts, we remain largely ignorant regarding the essential processes that regulate and define its function. While advances in functional neuroimaging have provided welcome windows into the coarse organisation of the neuronal networks that underlie a range of cognitive functions, they have largely ignored the fact that behaviour, and by inference brain function, unfolds dynamically. Modelling the brain's dynamics is therefore a critical step towards understanding the underlying mechanisms of its functioning. To date, models have concentrated on describing the sequential organisation of either abstract mental states (functionalism, hard AI) or the objectively measurable manifestations of the brain's ongoing activity (rCBF, EEG, MEG). While the former types of modelling approach may seem to better characterise brain function, they do so at the expense of not making a definite connection with the actual physical brain. Of the latter, only models of the EEG (or MEG) offer a temporal resolution well matched to the anticipated temporal scales of brain (mental processes) function. This chapter will outline the most pertinent of these modelling approaches, and illustrate, using the electrocortical model of Liley et al, how the detailed application of the methods of nonlinear dynamics and bifurcation theory is central to exploring and characterising their various dynamical features. The rich repertoire of dynamics revealed by such dynamical systems approaches arguably represents a critical step towards an understanding of the complexity of brain function.

  10. Spike Inference from Calcium Imaging Using Sequential Monte Carlo Methods

    PubMed Central

    Vogelstein, Joshua T.; Watson, Brendon O.; Packer, Adam M.; Yuste, Rafael; Jedynak, Bruno; Paninski, Liam

    2009-01-01

    Abstract As recent advances in calcium sensing technologies facilitate simultaneously imaging action potentials in neuronal populations, complementary analytical tools must also be developed to maximize the utility of this experimental paradigm. Although the observations here are fluorescence movies, the signals of interest—spike trains and/or time varying intracellular calcium concentrations—are hidden. Inferring these hidden signals is often problematic due to noise, nonlinearities, slow imaging rate, and unknown biophysical parameters. We overcome these difficulties by developing sequential Monte Carlo methods (particle filters) based on biophysical models of spiking, calcium dynamics, and fluorescence. We show that even in simple cases, the particle filters outperform the optimal linear (i.e., Wiener) filter, both by obtaining better estimates and by providing error bars. We then relax a number of our model assumptions to incorporate nonlinear saturation of the fluorescence signal, as well external stimulus and spike history dependence (e.g., refractoriness) of the spike trains. Using both simulations and in vitro fluorescence observations, we demonstrate temporal superresolution by inferring when within a frame each spike occurs. Furthermore, the model parameters may be estimated using expectation maximization with only a very limited amount of data (e.g., ∼5–10 s or 5–40 spikes), without the requirement of any simultaneous electrophysiology or imaging experiments. PMID:19619479

  11. Linear multistep methods, particle filtering and sequential Monte Carlo

    NASA Astrophysics Data System (ADS)

    Arnold, Andrea; Calvetti, Daniela; Somersalo, Erkki

    2013-08-01

    Numerical integration is the main bottleneck in particle filter methodologies for dynamic inverse problems to estimate model parameters, initial values, and non-observable components of an ordinary differential equation (ODE) system from partial, noisy observations, because proposals may result in stiff systems which first slow down or paralyze the time integration process, then end up being discarded. The immediate advantage of formulating the problem in a sequential manner is that the integration is carried out on shorter intervals, thus reducing the risk of long integration processes followed by rejections. We propose to solve the ODE systems within a particle filter framework with higher order numerical integrators which can handle stiffness and to base the choice of the variance of the innovation on estimates of the discretization errors. The application of linear multistep methods to particle filters gives a handle on the stability and accuracy of the propagation, and linking the innovation variance to the accuracy estimate helps keep the variance of the estimate as low as possible. The effectiveness of the methodology is demonstrated with a simple ODE system similar to those arising in biochemical applications.

  12. Characterization and Modeling of Segmental Dynamics in Silicone Based Nanocomposites

    SciTech Connect

    Maxwell, R S; Baumann, T; Gee, R; Maiti, A; Patel, M; Lewicki, J

    2009-03-27

    content on a number of silicone based nanocomposite systems. This data is providing improved insight into the structural contributions to the changes in segmental dynamics. Here we provide an overview of our ongoing work toward understanding the influence of the network structure on the physical and chemical properties of advanced composite elastomers, including material performance in severe environments (high temperature, high strains, high radiation fluxes).

  13. Making Career Decisions--A Sequential Elimination Approach.

    ERIC Educational Resources Information Center

    Gati, Itamar

    1986-01-01

    Presents a model for career decision making based on the sequential elimination of occupational alternatives, an adaptation for career decisions of Tversky's (1972) elimination-by-aspects theory of choice. The expected utility approach is reviewed as a representative compensatory model for career decisions. Advantages, disadvantages, and…

  14. Health-Related Quality of Life, Self-Efficacy and Enjoyment Keep the Socially Vulnerable Physically Active in Community-Based Physical Activity Programs: A Sequential Cohort Study

    PubMed Central

    Herens, Marion; Bakker, Evert Jan; van Ophem, Johan; Wagemakers, Annemarie; Koelen, Maria

    2016-01-01

    Physical inactivity is most commonly found in socially vulnerable groups. Dutch policies target these groups through community-based health-enhancing physical activity (CBHEPA) programs. As robust evidence on the effectiveness of this approach is limited, this study investigated whether CBHEPA programs contribute to an increase in and the maintenance of physical activity in socially vulnerable groups. In four successive cohorts, starting at a six-month interval, 268 participants from 19 groups were monitored for twelve months in seven CBHEPA programs. Data collection was based on repeated questionnaires. Socio-economic indicators, program participation and coping ability were measured at baseline. Physical activity, health-related quality of life and on-going program participation were measured three times. Self-efficacy and enjoyment were measured at baseline and at twelve months. Statistical analyses were based on a quasi-RCT design (independent t-tests), a comparison of participants and dropouts (Mann-Whitney test), and multilevel modelling to assess change in individual physical activity, including group level characteristics. Participants of CBHEPA programs are socially vulnerable in terms of low education (48.6%), low income (52.4%), non-Dutch origin (64.6%) and health-related quality of life outcomes. Physical activity levels were not below the Dutch average. No increase in physical activity levels over time was observed. The multilevel models showed significant positive associations between health-related quality of life, self-efficacy and enjoyment, and leisure-time physical activity over time. Short CBHEPA programs (10–13 weeks) with multiple trainers and gender-homogeneous groups were associated with lower physical activity levels over time. At twelve months, dropouts' leisure-time physical activity levels were significantly lower compared to continuing participants, as were health-related quality of life, self-efficacy and enjoyment outcomes. BMI and

  15. Smart designing of new hybrid materials based on brushite-alginate and monetite-alginate microspheres: bio-inspired for sequential nucleation and growth.

    PubMed

    Amer, Walid; Abdelouahdi, Karima; Ramananarivo, Hugo Ronald; Fihri, Aziz; El Achaby, Mounir; Zahouily, Mohamed; Barakat, Abdellatif; Djessas, Kamal; Clark, James; Solhy, Abderrahim

    2014-02-01

    In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX). PMID:24411386

  16. Secure sequential transmission of quantum information

    NASA Astrophysics Data System (ADS)

    Jeong, Kabgyun; Kim, Jaewan

    2015-09-01

    We propose a quantum communication protocol that can be used to transmit any quantum state, one party to another via several intermediate nodes, securely on quantum communication network. The scheme makes use of the sequentially chained and approximate version of private quantum channels satisfying certain commutation relation of n-qubit Pauli operations. In this paper, we study the sequential structure, security analysis, and efficiency of the quantum sequential transmission protocol in depth.

  17. Speciation of arsenic (III) and arsenic (V) based on quenching of CdS quantum dots fluorescence using hybrid sequential injection-stopped flow injection gas-diffusion system

    NASA Astrophysics Data System (ADS)

    Butwong, Nutthaya; Srijaranai, Supalax; Ngeontae, Wittaya; Burakham, Rodjana

    2012-11-01

    A hybrid sequential injection-stopped flow injection system was developed for the speciation of arsenic based on the quenching of mercaptoacetic acid capped cadmium sulfide quantum dots (CdS-MAA QDs) fluorescence intensity. The analytical procedure involves the generation of arsine from As(III) by sodium borohydride in acetate buffer medium pH 6.0. The generated arsine (donor stream) diffuses across the PTFE membrane of the gas-diffusion unit into an acceptor stream and then interacts with CdS-MAA QDs. Total arsenic was determined after pre-reduction of As(V) to As(III) with 1% (m/v) mercaptoacetic acid. Concentration of As(V) in the sample solutions can be deduced from the difference of total arsenic and As(III). Optimization of the experimental conditions and instrumental parameters were investigated. Under optimal conditions, limits of detection were 20 μg L-1 for As(III) and 40 μg L-1 for As(V). Recoveries in the range 84-103% were obtained from sediment sample.

  18. Structural features of sequential weak measurements

    NASA Astrophysics Data System (ADS)

    Diósi, Lajos

    2016-07-01

    We discuss the abstract structure of sequential weak measurement (WM) of general observables. In all orders, the sequential WM correlations without postselection yield the corresponding correlations of the Wigner function, offering direct quantum tomography through the moments of the canonical variables. Correlations in spin-1/2 sequential weak measurements coincide with those in strong measurements, they are constrained kinematically, and they are equivalent with single measurements. In sequential WMs with postselection, an anomaly occurs, different from the weak value anomaly of single WMs. In particular, the spread of polarization σ ̂ as measured in double WMs of σ ̂ will diverge for certain orthogonal pre- and postselected states.

  19. 1H nuclear magnetic resonance of modified bases of valine transfer ribonucleic acid (Escherichia coli). A direct monitor of sequential thermal unfolding.

    PubMed

    Kastrup, R V; Schmidt, P G

    1975-08-12

    Proton magnetic resonances at 220 MHz from three nucleotide residues of valine I tRNA (Escherichia coli) serve as intrinsic probes of local molecular structure. Resonances from the methyl group of ribothymidine, the methyl group of N6-methyladenosine, and the C-5 methylene of dihydrouridine monitor separate conformational transitions in the TpsiC, anticodon, and dihydrouridine loops, respectively. As the temperature is raised in a solution containing 0.23 M Na+ and no Mg2+, the dihydrouridine region melts with a Tm of 55 degrees, the anticodon region at 58 degrees, and the TpsiC region at 67 degrees. The dihydrouridine nuclear magnetic resonance (NMR) transition correlates with the major change in absorbance monitored in the uv at 330 nm which is ascribed to structural pertubations near the 4-thiouracil moiety. On the NMR time scale slow exchange is seen throughout the temperature range for dihydrouridine and below the apparent Tm for the ribothymidine methyl group. Chemical shift and line width differences between folded and unfolded forms of the polynucleotide indicate that, in the native structure, ribothymidine is in a highly structured region and N6-methyladenosine is in a somewhat less restricted environment. Narrow line widths for the C-5 methylene triplet are found over the whole temperature range indicating that this base is undergoing rapid internal reorientation relative to the overall macromolecule. PMID:1100098

  20. The P300-based, complex trial protocol for concealed information detection resists any number of sequential countermeasures against up to five irrelevant stimuli.

    PubMed

    Labkovsky, Elena; Rosenfeld, J Peter

    2012-03-01

    We previously tested the P300-based Complex Trial protocol for deception detection against 2 and 4 countered of 4 irrelevant stimuli. The protocol detected 90-100% of these subjects with <10% false positives. We have also shown that Reaction Time (RT) to the first trial stimulus is increased (group effect) with countermeasure use. We also reported a new P900 component associated with countermeasure use when 2 of 4 irrelevants are countered. In the present study we report data from 4 new groups and re-present for comparison previously collected data to have 7 groups: an innocent control, a guilty group not using countermeasures, and 5 guilty/countermeasure groups who counter from 1 to all 5 stimuli presented (4 irrelevants plus a probe). Subjects were detected at rates varying from 92 to 100% in the 6 guilty groups (n = 12 or 13 per group). There was 1 false positive in 13 innocent subjects. Additionally, 41 of 60 CM users were identified with RT as using countermeasures. P900 appeared in the 2 groups using 2 and 3 countermeasures. PMID:21965119

  1. Integrated Turbine-Based Combined Cycle Dynamic Simulation Model

    NASA Technical Reports Server (NTRS)

    Haid, Daniel A.; Gamble, Eric J.

    2011-01-01

    A Turbine-Based Combined Cycle (TBCC) dynamic simulation model has been developed to demonstrate all modes of operation, including mode transition, for a turbine-based combined cycle propulsion system. The High Mach Transient Engine Cycle Code (HiTECC) is a highly integrated tool comprised of modules for modeling each of the TBCC systems whose interactions and controllability affect the TBCC propulsion system thrust and operability during its modes of operation. By structuring the simulation modeling tools around the major TBCC functional modes of operation (Dry Turbojet, Afterburning Turbojet, Transition, and Dual Mode Scramjet) the TBCC mode transition and all necessary intermediate events over its entire mission may be developed, modeled, and validated. The reported work details the use of the completed model to simulate a TBCC propulsion system as it accelerates from Mach 2.5, through mode transition, to Mach 7. The completion of this model and its subsequent use to simulate TBCC mode transition significantly extends the state-of-the-art for all TBCC modes of operation by providing a numerical simulation of the systems, interactions, and transient responses affecting the ability of the propulsion system to transition from turbine-based to ramjet/scramjet-based propulsion while maintaining constant thrust.

  2. IMPaCT Back study protocol. Implementation of subgrouping for targeted treatment systems for low back pain patients in primary care: a prospective population-based sequential comparison

    PubMed Central

    2010-01-01

    Background Prognostic assessment tools to identify subgroups of patients at risk of persistent low back pain who may benefit from targeted treatments have been developed and validated in primary care. The IMPaCT Back study is investigating the effects of introducing and supporting a subgrouping for targeted treatment system in primary care. Methods/Design A prospective, population-based, quality improvement study in one Primary Care Trust in England with a before and after design. Phases 1 and 3 collect data on current practice, attitudes and behaviour of health care practitioners, patients' outcomes and health care costs. Phase 2 introduces and supports the subgrouping for targeted treatment system, via a multi-component, quality improvement intervention that includes educational courses and outreach visits led by opinion leaders, audit/feedback, mentoring and organisational support to embed the subgrouping tools within IT and clinical management systems. We aim to recruit 1000 low back pain patients aged 18 years and over consulting 7 GP practices within one Primary Care Trust in England, UK. The study includes GPs in participating practices and physiotherapists in associated services. The primary objective is to determine the effect of the subgrouping for targeted treatment system on back pain related disability and catastrophising at 2 and 6 months, comparing data from phase 1 with phase 3. Key secondary objectives are to determine the impact on: a) GPs' and physiotherapists' attitudes and behaviour regarding low back pain; b) The process of care that patients receive; c) The cost-effectiveness and sustainability of the new clinical system. Discussion This paper details the rationale, design, methods, planned analysis and operational aspects of the IMPaCT Back study. We aim to determine whether the new subgrouping for targeted treatment system is implemented and sustained in primary care, and evaluate its impact on clinical decision-making, patient outcomes and

  3. Generic sequential sampling for metamodel approximations

    SciTech Connect

    Turner, C. J.; Campbell, M. I.

    2003-01-01

    Metamodels approximate complex multivariate data sets from simulations and experiments. These data sets often are not based on an explicitly defined function. The resulting metamodel represents a complex system's behavior for subsequent analysis or optimization. Often an exhaustive data search to obtain the data for the metalnodel is impossible, so an intelligent sampling strategy is necessary. While inultiple approaches have been advocated, the majority of these approaches were developed in support of a particular class of metamodel, known as a Kriging. A more generic, cotninonsense approach to this problem allows sequential sampling techniques to be applied to other types of metamodeis. This research compares recent search techniques for Kriging inetamodels with a generic, inulti-criteria approach combined with a new type of B-spline metamodel. This B-spline metamodel is competitive with prior results obtained with a Kriging metamodel. Furthermore, the results of this research highlight several important features necessary for these techniques to be extended to more complex domains.

  4. Collaborative, Sequential and Isolated Decisions in Design

    NASA Technical Reports Server (NTRS)

    Lewis, Kemper; Mistree, Farrokh

    1997-01-01

    The Massachusetts Institute of Technology (MIT) Commission on Industrial Productivity, in their report Made in America, found that six recurring weaknesses were hampering American manufacturing industries. The two weaknesses most relevant to product development were 1) technological weakness in development and production, and 2) failures in cooperation. The remedies to these weaknesses are considered the essential twin pillars of CE: 1) improved development process, and 2) closer cooperation. In the MIT report, it is recognized that total cooperation among teams in a CE environment is rare in American industry, while the majority of the design research in mathematically modeling CE has assumed total cooperation. In this paper, we present mathematical constructs, based on game theoretic principles, to model degrees of collaboration characterized by approximate cooperation, sequential decision making and isolation. The design of a pressure vessel and a passenger aircraft are included as illustrative examples.

  5. Towards chemiluminescence detection in micro-sequential injection lab-on-valve format: a proof of concept based on the reaction between Fe(II) and luminol in seawater.

    PubMed

    Oliveira, Hugo M; Grand, Maxime M; Ruzicka, Jaromir; Measures, Christopher I

    2015-02-01

    Micro-sequential injection lab-on-valve (µSI-LOV) is a well-established analytical platform for absorbance and fluorescence based assays but its applicability to chemiluminescence detection remains largely unexplored. In this work, we describe a novel fluidic protocol and two distinct strategies for photon collection that enable chemiluminescence detection using µSI-LOV for the first time. To illustrate this proof of concept, we selected the reaction between Fe(II) and luminol and developed a preliminary protocol for Fe(II) determinations in acidified seawater. The optimized fluidic strategy consists of holding 100 µL of the luminol reagent in a confined zone of the LOV and then displacing it with 50 µL of sample while monitoring the chemiluminescent product. Detection is achieved using two strategies: one based on a bifurcated optical fiber and the other based on a customized detection window created by mounting a photomultiplier tube atop of the LOV device. We show that detection is possible using both strategies but that the window strategy yields significantly enhanced sensitivity (355×) due to the larger detection area. In our final experimental conditions and using window detection, it was possible to achieve a limit of detection (LOD) of 1 nmol L(-1) and to quantify Fe(II) in acidified seawater samples up to 20.00 nmol L(-1) with high precision (RSD<6%). These analytical features combined with the long-term stability of luminol solution and the full automation and low reagent consumption make this approach a promising analytical tool for shipboard analysis of Fe(II). The intrinsic capacity of the LOV to operate at a low microliter level and to handle solid phases also opens up a new avenue for chemiluminescence applications. Moreover, this contribution shows that LOV can be a universal platform for optical detection, capable of absorbance, fluorescence and luminescence measurements in a single instrument setup. PMID:25435235

  6. Sequential detection of web defects

    DOEpatents

    Eichel, Paul H.; Sleefe, Gerard E.; Stalker, K. Terry; Yee, Amy A.

    2001-01-01

    A system for detecting defects on a moving web having a sequential series of identical frames uses an imaging device to form a real-time camera image of a frame and a comparitor to comparing elements of the camera image with corresponding elements of an image of an exemplar frame. The comparitor provides an acceptable indication if the pair of elements are determined to be statistically identical; and a defective indication if the pair of elements are determined to be statistically not identical. If the pair of elements is neither acceptable nor defective, the comparitor recursively compares the element of said exemplar frame with corresponding elements of other frames on said web until one of the acceptable or defective indications occur.

  7. Sequential power-up circuit

    DOEpatents

    Kronberg, James W.

    1992-01-01

    A sequential power-up circuit for starting several electrical load elements in series to avoid excessive current surge, comprising a voltage ramp generator and a set of voltage comparators, each comparator having a different reference voltage and interfacing with a switch that is capable of turning on one of the load elements. As the voltage rises, it passes the reference voltages one at a time and causes the switch corresponding to that voltage to turn on its load element. The ramp is turned on and off by a single switch or by a logic-level electrical signal. The ramp rate for turning on the load element is relatively slow and the rate for turning the elements off is relatively fast. Optionally, the duration of each interval of time between the turning on of the load elements is programmable.

  8. Sequential power-up circuit

    DOEpatents

    Kronberg, J.W.

    1992-06-02

    A sequential power-up circuit for starting several electrical load elements in series to avoid excessive current surge, comprising a voltage ramp generator and a set of voltage comparators, each comparator having a different reference voltage and interfacing with a switch that is capable of turning on one of the load elements. As the voltage rises, it passes the reference voltages one at a time and causes the switch corresponding to that voltage to turn on its load element. The ramp is turned on and off by a single switch or by a logic-level electrical signal. The ramp rate for turning on the load element is relatively slow and the rate for turning the elements off is relatively fast. Optionally, the duration of each interval of time between the turning on of the load elements is programmable. 2 figs.

  9. Modeling apple surface temperature dynamics based on weather data.

    PubMed

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

  10. Gradient-based MCMC samplers for dynamic causal modelling

    PubMed Central

    Sengupta, Biswa; Friston, Karl J.; Penny, Will D.

    2016-01-01

    In this technical note, we derive two MCMC (Markov chain Monte Carlo) samplers for dynamic causal models (DCMs). Specifically, we use (a) Hamiltonian MCMC (HMC-E) where sampling is simulated using Hamilton’s equation of motion and (b) Langevin Monte Carlo algorithm (LMC-R and LMC-E) that simulates the Langevin diffusion of samples using gradients either on a Euclidean (E) or on a Riemannian (R) manifold. While LMC-R requires minimal tuning, the implementation of HMC-E is heavily dependent on its tuning parameters. These parameters are therefore optimised by learning a Gaussian process model of the time-normalised sample correlation matrix. This allows one to formulate an objective function that balances tuning parameter exploration and exploitation, furnishing an intervention-free inference scheme. Using neural mass models (NMMs)—a class of biophysically motivated DCMs—we find that HMC-E is statistically more efficient than LMC-R (with a Riemannian metric); yet both gradient-based samplers are far superior to the random walk Metropolis algorithm, which proves inadequate to steer away from dynamical instability. PMID:26213349

  11. Nanoscale dynamics and aging of fibrous peptide-based gels

    SciTech Connect

    Dudukovic, Nikola A.; Zukoski, Charles F.

    2014-10-28

    Solutions of the aromatic dipeptide derivative molecule fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) in dimethyl sulfoxide produce fibrous gels when mixed with water. We study the evolution of density fluctuations of this three-component system using X-ray photon correlation spectroscopy (XPCS) and compare these results to the macroscopic rheology of the gels and optical observations of the microstructure evolution. At the investigated scattering angles, the intensity autocorrelation functions do not follow behavior expected for simple diffusion of individual Fmoc-FF molecules localized within cages of nearest neighbors. Instead, the dynamics are associated with density fluctuations on length scales of ∼10–100 nm arising from disaggregation and reformation of fibers, leading to an increasingly uniform network. This process is correlated with the growth of the elastic modulus, which saturates at long times. Autocorrelation functions and relaxation times acquired from XPCS measurements are consistent with relaxation rates of structures at dynamic equilibrium. This study provides further support to the concept of exploring peptide-based gelators as valence-limited patchy particles capable of forming equilibrium gels.

  12. Residential Consumption Scheduling Based on Dynamic User Profiling

    NASA Astrophysics Data System (ADS)

    Mangiatordi, Federica; Pallotti, Emiliano; Del Vecchio, Paolo; Capodiferro, Licia

    Deployment of household appliances and of electric vehicles raises the electricity demand in the residential areas and the impact of the building's electrical power. The variations of electricity consumption across the day, may affect both the design of the electrical generation facilities and the electricity bill, mainly when a dynamic pricing is applied. This paper focuses on an energy management system able to control the day-ahead electricity demand in a residential area, taking into account both the variability of the energy production costs and the profiling of the users. The user's behavior is dynamically profiled on the basis of the tasks performed during the previous days and of the tasks foreseen for the current day. Depending on the size and on the flexibility in time of the user tasks, home inhabitants are grouped in, one over N, energy profiles, using a k-means algorithm. For a fixed energy generation cost, each energy profile is associated to a different hourly energy cost. The goal is to identify any bad user profile and to make it pay a highest bill. A bad profile example is when a user applies a lot of consumption tasks and low flexibility in task reallocation time. The proposed energy management system automatically schedules the tasks, solving a multi-objective optimization problem based on an MPSO strategy. The goals, when identifying bad users profiles, are to reduce the peak to average ratio in energy demand, and to minimize the energy costs, promoting virtuous behaviors.

  13. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    PubMed Central

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

  14. Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers

    DOE PAGESBeta

    Bachand, George D.; Stevens, Mark J.; Spoerke, Erik David

    2015-04-09

    For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. In addition, one intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are onemore » of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.« less

  15. Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers

    SciTech Connect

    Bachand, George D.; Stevens, Mark J.; Spoerke, Erik David

    2015-04-09

    For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. In addition, one intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are one of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.

  16. Dynamic calibration of agent-based models using data assimilation.

    PubMed

    Ward, Jonathan A; Evans, Andrew J; Malleson, Nicolas S

    2016-04-01

    A widespread approach to investigating the dynamical behaviour of complex social systems is via agent-based models (ABMs). In this paper, we describe how such models can be dynamically calibrated using the ensemble Kalman filter (EnKF), a standard method of data assimilation. Our goal is twofold. First, we want to present the EnKF in a simple setting for the benefit of ABM practitioners who are unfamiliar with it. Second, we want to illustrate to data assimilation experts the value of using such methods in the context of ABMs of complex social systems and the new challenges these types of model present. We work towards these goals within the context of a simple question of practical value: how many people are there in Leeds (or any other major city) right now? We build a hierarchy of exemplar models that we use to demonstrate how to apply the EnKF and calibrate these using open data of footfall counts in Leeds. PMID:27152214

  17. Fast content-based image retrieval using dynamic cluster tree

    NASA Astrophysics Data System (ADS)

    Chen, Jinyan; Sun, Jizhou; Wu, Rongteng; Zhang, Yaping

    2008-03-01

    A novel content-based image retrieval data structure is developed in present work. It can improve the searching efficiency significantly. All images are organized into a tree, in which every node is comprised of images with similar features. Images in a children node have more similarity (less variance) within themselves in relative to its parent. It means that every node is a cluster and each of its children nodes is a sub-cluster. Information contained in a node includes not only the number of images, but also the center and the variance of these images. Upon the addition of new images, the tree structure is capable of dynamically changing to ensure the minimization of total variance of the tree. Subsequently, a heuristic method has been designed to retrieve the information from this tree. Given a sample image, the probability of a tree node that contains the similar images is computed using the center of the node and its variance. If the probability is higher than a certain threshold, this node will be recursively checked to locate the similar images. So will its children nodes if their probability is also higher than that threshold. If no sufficient similar images were founded, a reduced threshold value would be adopted to initiate a new seeking from the root node. The search terminates when it found sufficient similar images or the threshold value is too low to give meaningful sense. Experiments have shown that the proposed dynamic cluster tree is able to improve the searching efficiency notably.

  18. Tyre pressure monitoring using a dynamical model-based estimator

    NASA Astrophysics Data System (ADS)

    Reina, Giulio; Gentile, Angelo; Messina, Arcangelo

    2015-04-01

    In the last few years, various control systems have been investigated in the automotive field with the aim of increasing the level of safety and stability, avoid roll-over, and customise handling characteristics. One critical issue connected with their integration is the lack of state and parameter information. As an example, vehicle handling depends to a large extent on tyre inflation pressure. When inflation pressure drops, handling and comfort performance generally deteriorate. In addition, it results in an increase in fuel consumption and in a decrease in lifetime. Therefore, it is important to keep tyres within the normal inflation pressure range. This paper introduces a model-based approach to estimate online tyre inflation pressure. First, basic vertical dynamic modelling of the vehicle is discussed. Then, a parameter estimation framework for dynamic analysis is presented. Several important vehicle parameters including tyre inflation pressure can be estimated using the estimated states. This method aims to work during normal driving using information from standard sensors only. On the one hand, the driver is informed about the inflation pressure and he is warned for sudden changes. On the other hand, accurate estimation of the vehicle states is available as possible input to onboard control systems.

  19. Nanoscale dynamics and aging of fibrous peptide-based gels.

    PubMed

    Dudukovic, Nikola A; Zukoski, Charles F

    2014-10-28

    Solutions of the aromatic dipeptide derivative molecule fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) in dimethyl sulfoxide produce fibrous gels when mixed with water. We study the evolution of density fluctuations of this three-component system using X-ray photon correlation spectroscopy (XPCS) and compare these results to the macroscopic rheology of the gels and optical observations of the microstructure evolution. At the investigated scattering angles, the intensity autocorrelation functions do not follow behavior expected for simple diffusion of individual Fmoc-FF molecules localized within cages of nearest neighbors. Instead, the dynamics are associated with density fluctuations on length scales of ~10-100 nm arising from disaggregation and reformation of fibers, leading to an increasingly uniform network. This process is correlated with the growth of the elastic modulus, which saturates at long times. Autocorrelation functions and relaxation times acquired from XPCS measurements are consistent with relaxation rates of structures at dynamic equilibrium. This study provides further support to the concept of exploring peptide-based gelators as valence-limited patchy particles capable of forming equilibrium gels. PMID:25362339

  20. Nanoscale dynamics and aging of fibrous peptide-based gels

    NASA Astrophysics Data System (ADS)

    Dudukovic, Nikola A.; Zukoski, Charles F.

    2014-10-01

    Solutions of the aromatic dipeptide derivative molecule fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) in dimethyl sulfoxide produce fibrous gels when mixed with water. We study the evolution of density fluctuations of this three-component system using X-ray photon correlation spectroscopy (XPCS) and compare these results to the macroscopic rheology of the gels and optical observations of the microstructure evolution. At the investigated scattering angles, the intensity autocorrelation functions do not follow behavior expected for simple diffusion of individual Fmoc-FF molecules localized within cages of nearest neighbors. Instead, the dynamics are associated with density fluctuations on length scales of ˜10-100 nm arising from disaggregation and reformation of fibers, leading to an increasingly uniform network. This process is correlated with the growth of the elastic modulus, which saturates at long times. Autocorrelation functions and relaxation times acquired from XPCS measurements are consistent with relaxation rates of structures at dynamic equilibrium. This study provides further support to the concept of exploring peptide-based gelators as valence-limited patchy particles capable of forming equilibrium gels.

  1. Autonomous Navigation of Small Uavs Based on Vehicle Dynamic Model

    NASA Astrophysics Data System (ADS)

    Khaghani, M.; Skaloud, J.

    2016-03-01

    This paper presents a novel approach to autonomous navigation for small UAVs, in which the vehicle dynamic model (VDM) serves as the main process model within the navigation filter. The proposed method significantly increases the accuracy and reliability of autonomous navigation, especially for small UAVs with low-cost IMUs on-board. This is achieved with no extra sensor added to the conventional INS/GNSS setup. This improvement is of special interest in case of GNSS outages, where inertial coasting drifts very quickly. In the proposed architecture, the solution to VDM equations provides the estimate of position, velocity, and attitude, which is updated within the navigation filter based on available observations, such as IMU data or GNSS measurements. The VDM is also fed with the control input to the UAV, which is available within the control/autopilot system. The filter is capable of estimating wind velocity and dynamic model parameters, in addition to navigation states and IMU sensor errors. Monte Carlo simulations reveal major improvements in navigation accuracy compared to conventional INS/GNSS navigation system during the autonomous phase, when satellite signals are not available due to physical obstruction or electromagnetic interference for example. In case of GNSS outages of a few minutes, position and attitude accuracy experiences improvements of orders of magnitude compared to inertial coasting. It means that during such scenario, the position-velocity-attitude (PVA) determination is sufficiently accurate to navigate the UAV to a home position without any signal that depends on vehicle environment.

  2. Dynamic calibration of agent-based models using data assimilation

    PubMed Central

    Ward, Jonathan A.; Evans, Andrew J.; Malleson, Nicolas S.

    2016-01-01

    A widespread approach to investigating the dynamical behaviour of complex social systems is via agent-based models (ABMs). In this paper, we describe how such models can be dynamically calibrated using the ensemble Kalman filter (EnKF), a standard method of data assimilation. Our goal is twofold. First, we want to present the EnKF in a simple setting for the benefit of ABM practitioners who are unfamiliar with it. Second, we want to illustrate to data assimilation experts the value of using such methods in the context of ABMs of complex social systems and the new challenges these types of model present. We work towards these goals within the context of a simple question of practical value: how many people are there in Leeds (or any other major city) right now? We build a hierarchy of exemplar models that we use to demonstrate how to apply the EnKF and calibrate these using open data of footfall counts in Leeds. PMID:27152214

  3. Dynamic optimization of a copolymerization reactor using tabu search.

    PubMed

    Anand, P; Rao, M Bhagvanth; Venkateswarlu, Ch

    2015-03-01

    A novel multistage dynamic optimization strategy based on meta-heuristic tabu search (TS) is proposed and evaluated through sequential and simultaneous implementation procedures by applying it to a semi-batch styrene-acrylonitrile (SAN) copolymerization reactor. The adaptive memory and responsive exploration features of TS are exploited to design the dynamic optimization strategy and compute the optimal control policies for temperature and monomer addition rate so as to achieve the desired product quality parameters expressed in terms of single and multiple objectives. The dynamic optimization results of TS sequential and TS simultaneous implementation strategies are analyzed and compared with those of a conventional optimization technique based on iterative dynamic programming (IDP). The simulation results demonstrate the usefulness of TS for optimal control of transient dynamic systems. PMID:25466914

  4. Development of an empirically based dynamic biomechanical strength model

    NASA Technical Reports Server (NTRS)

    Pandya, A.; Maida, J.; Aldridge, A.; Hasson, S.; Woolford, B.

    1992-01-01

    The focus here is on the development of a dynamic strength model for humans. Our model is based on empirical data. The shoulder, elbow, and wrist joints are characterized in terms of maximum isolated torque, position, and velocity in all rotational planes. This information is reduced by a least squares regression technique into a table of single variable second degree polynomial equations determining the torque as a function of position and velocity. The isolated joint torque equations are then used to compute forces resulting from a composite motion, which in this case is a ratchet wrench push and pull operation. What is presented here is a comparison of the computed or predicted results of the model with the actual measured values for the composite motion.

  5. Dynamic infrared scene projectors based upon the DMD

    NASA Astrophysics Data System (ADS)

    Beasley, D. Brett; Bender, Matt; Crosby, Jay; Messer, Tim

    2009-02-01

    The Micromirror Array Projector System (MAPS) is an advanced dynamic scene projector system developed by Optical Sciences Corporation (OSC) for Hardware-In-the-Loop (HWIL) simulation and sensor test applications. The MAPS is based upon the Texas Instruments Digital Micromirror Device (DMD) which has been modified to project high resolution, realistic imagery suitable for testing sensors and seekers operating in the UV, visible, NIR, and IR wavebands. Since the introduction of the first MAPS in 2001, OSC has continued to improve the technology and develop systems for new projection and Electro-Optical (E-O) test applications. This paper reviews the basic MAPS design and performance capabilities. We also present example projectors and E-O test sets designed and fabricated by OSC in the last 7 years. Finally, current research efforts and new applications of the MAPS technology are discussed.

  6. Motor Schema-Based Cellular Automaton Model for Pedestrian Dynamics

    NASA Astrophysics Data System (ADS)

    Weng, Wenguo; Hasemi, Yuji; Fan, Weicheng

    A new cellular automaton model for pedestrian dynamics based on motor schema is presented. Each pedestrian is treated as an intelligent mobile robot, and motor schemas including move-to-goal, avoid-away and avoid-around drive pedestrians to interact with their environment. We investigate the phenomenon of many pedestrians with different move velocities escaping from a room. The results show that the pedestrian with high velocity have predominance in competitive evacuation, if we only consider repulsion from or avoiding around other pedestrians, and interaction with each other leads to disordered evacuation, i.e., decreased evacuation efficiency. Extensions of the model using learning algorithms for controlling pedestrians, i.e., reinforcement learning, neural network and genetic algorithms, etc. are noted.

  7. Fluorescent protein-based biosensors: resolving spatiotemporal dynamics of signaling

    PubMed Central

    DiPilato, Lisa M.; Zhang, Jin

    2009-01-01

    Summary Cellular processes are orchestrated by the precise coordination and regulation of molecular events in the cell. Fluorescent protein-based biosensors coupled with live-cell imaging have enabled the visualization of these events in real time and helped shape some of the current concepts of signal transduction, such as spatial compartmentation. The quantitative information produced by these tools has been incorporated into mathematical models that are capable of predicting highly complex and dynamic behaviors of cellular signaling networks, thus providing a systems level understanding of how pathways interact to produce a functional response. Finally, with technological advances in high throughput and in vivo imaging, these molecular tools promise to continually engender significant contributions to our understanding of cellular processes under normal and diseased conditions. PMID:19910237

  8. A consensus-based dynamics for market volumes

    NASA Astrophysics Data System (ADS)

    Sabatelli, Lorenzo; Richmond, Peter

    2004-12-01

    We develop a model of trading orders based on opinion dynamics. The agents may be thought as the share holders of a major mutual fund rather than as direct traders. The balance between their buy and sell orders determines the size of the fund order (volume) and has an impact on prices and indexes. We assume agents interact simultaneously to each other through a Sznajd-like interaction. Their degree of connection is determined by the probability of changing opinion independently of what their neighbours are doing. We assume that such a probability may change randomly, after each transaction, of an amount proportional to the relative difference between the volatility then measured and a benchmark that we assume to be an exponential moving average of the past volume values. We show how this simple model is compatible with some of the main statistical features observed for the asset volumes in financial markets.

  9. Identification of dynamical biological systems based on random effects models.

    PubMed

    Batista, Levy; Bastogne, Thierry; Djermoune, El-Hadi

    2015-01-01

    System identification is a data-driven modeling approach more and more used in biology and biomedicine. In this application context, each assay is always repeated to estimate the response variability. The inference of the modeling conclusions to the whole population requires to account for the inter-individual variability within the modeling procedure. One solution consists in using random effects models but up to now no similar approach exists in the field of dynamical system identification. In this article, we propose a new solution based on an ARX (Auto Regressive model with eXternal inputs) structure using the EM (Expectation-Maximisation) algorithm for the estimation of the model parameters. Simulations show the relevance of this solution compared with a classical procedure of system identification repeated for each subject. PMID:26736981

  10. Grid-based representation and dynamic visualization of ionospheric tomography

    NASA Astrophysics Data System (ADS)

    He, L. M.; Yang, Y.; Su, C.; Yu, J. Q.; Yang, F.; Wu, L. X.

    2013-10-01

    The ionosphere is a dynamic system with complex structures. With the development of abundant global navigation satellite systems, the ionospheric electron density in different altitudes and its time variations can be obtained by ionospheric tomography technique using GNSS observations collected by the continuously operating GNSS tracking stations distributed over globe. However, it is difficult to represent and analyze global and local ionospheric electron density variations in three-dimensional (3D) space due to its complex structures. In this paper, we introduce a grid-based system to overcome this constraint. First, we give the principles, algorithms and procedures of GNSS-based ionospheric tomography technique. Then, the earth system spatial grid (ESSG) based on the spheroid degenerated octree grid (SDOG) is introduced in detail. Finally, more than 400 continuously operating GNSS receivers from the International GNSS Service are utilized to realize global ionospheric tomography, and then the ESSG is used to organize and express the tomography results in 4D, including 3 spatial dimensions and time.

  11. Human insulin dynamics in women: a physiologically based model.

    PubMed

    Weiss, Michael; Tura, Andrea; Kautzky-Willer, Alexandra; Pacini, Giovanni; D'Argenio, David Z

    2016-02-01

    Currently available models of insulin dynamics are mostly based on the classical compartmental structure and, thus, their physiological utility is limited. In this work, we describe the development of a physiologically based model and its application to data from 154 patients who underwent an insulin-modified intravenous glucose tolerance test (IM-IVGTT). To determine the time profile of endogenous insulin delivery without using C-peptide data and to evaluate the transcapillary transport of insulin, the hepatosplanchnic, renal, and peripheral beds were incorporated into the circulatory model as separate subsystems. Physiologically reasonable population mean estimates were obtained for all estimated model parameters, including plasma volume, interstitial volume of the peripheral circulation (mainly skeletal muscle), uptake clearance into the interstitial space, hepatic and renal clearance, as well as total insulin delivery into plasma. The results indicate that, at a population level, the proposed physiologically based model provides a useful description of insulin disposition, which allows for the assessment of muscle insulin uptake. PMID:26608654

  12. Dynamic functional connectivity using state-based dynamic community structure: method and application to opioid analgesia.

    PubMed

    Robinson, Lucy F; Atlas, Lauren Y; Wager, Tor D

    2015-03-01

    We present a new method, State-based Dynamic Community Structure, that detects time-dependent community structure in networks of brain regions. Most analyses of functional connectivity assume that network behavior is static in time, or differs between task conditions with known timing. Our goal is to determine whether brain network topology remains stationary over time, or if changes in network organization occur at unknown time points. Changes in network organization may be related to shifts in neurological state, such as those associated with learning, drug uptake or experimental conditions. Using a hidden Markov stochastic blockmodel, we define a time-dependent community structure. We apply this approach to data from a functional magnetic resonance imaging experiment examining how contextual factors influence drug-induced analgesia. Results reveal that networks involved in pain, working memory, and emotion show distinct profiles of time-varying connectivity. PMID:25534114

  13. Self-organizing Symbol Acquisition and Motion Generation based on Dynamics-based Information Processing System

    NASA Astrophysics Data System (ADS)

    Okada, Masafumi; Nakamura, Daisuke; Nakamura, Yoshihiko

    The symbol acquisition and manipulation abilities are one of the inherent characteristics of human beings comparing with other creatures. In this paper, based on recurrent self-organizing map and dynamics-based information processing system, we propose a dynamics based self-organizing map (DBSOM). This method enables designing a topological map using time sequence data, which causes recognition and generation of the robot motion. Using this method, we design the self-organizing symbol acquisition system and robot motion generation system for a humanoid robot. By implementing DBSOM to the robot in the real world, we realize the symbol acquisition from the experimental data and investigate the spatial property of the obtained DBSOM.

  14. Evaluation of Quantitative Performance of Sequential Immobilized Metal Affinity Chromatographic Enrichment for Phosphopeptides

    PubMed Central

    Sun, Zeyu; Hamilton, Karyn L.; Reardon, Kenneth F.

    2014-01-01

    We evaluated a sequential elution protocol from immobilized metal affinity chromatography (SIMAC) employing gallium-based immobilized metal affinity chromatography (IMAC) in conjunction with titanium-dioxide-based metal oxide affinity chromatography (MOAC). The quantitative performance of this SIMAC enrichment approach, assessed in terms of repeatability, dynamic range, and linearity, was evaluated using a mixture composed of tryptic peptides from caseins, bovine serum albumin, and phosphopeptide standards. While our data demonstrate the overall consistent performance of the SIMAC approach under various loading conditions, the results also revealed that the method had limited repeatability and linearity for most phosphopeptides tested, and different phosphopeptides were found to have different linear ranges. These data suggest that, unless additional strategies are used, SIMAC should be regarded as a semi-quantitative method when used in large-scale phosphoproteomics studies in complex backgrounds. PMID:24096195

  15. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    DOE PAGESBeta

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; et al

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

  16. Estrogen, testosterone, and sequential movement in men.

    PubMed

    Siegel, Jessica A; Young, Laura A; Neiss, Michelle B; Samuels, Mary H; Roselli, Charles E; Janowsky, Jeri S

    2008-10-01

    Behavioral and physiological data suggest that the striatal dopaminergic system is important in the production and execution of sequential movements. Striatal function is also modulated by sex hormones, and previous studies show that estradiol is related to sequential movement in women. The authors examined whether sex hormones are involved in the production of sequential movement in healthy older and younger men. Testosterone was modified for a 6-week period such that levels in older men matched those of younger men, the conversion of testosterone to estradiol was blocked, the production of testosterone was blocked, or the men received no treatment (placebo). Sequential movement was measured before and after hormone treatment. Older men were slower and more accurate than younger men on the sequential movement task pre- and posttreatment. Hormone manipulation had no effect on movement speed. Hormone levels were not correlated with sequential movement performance in either older or younger men, suggesting that sex hormones do not modulate sequential movement in men, and hormone replacement may not restore a loss of sequential movement ability in elderly men or men with Parkinson's disease. PMID:18823152

  17. Measuring Sequential Processing Skills in Young Children.

    ERIC Educational Resources Information Center

    McDaniel, Ernest D.

    This study investigates (1) the relationship of two potentially valuable measures of sequential processing to each other and to a measure of digit span, and (2) the relationships among tests of sequential processing and other measures of cognitive functioning. Subjects were 188 first grade students who had been screened in kindergarten for risk of…

  18. Web-based dynamic Delphi: a new survey instrument

    NASA Astrophysics Data System (ADS)

    Yao, JingTao; Liu, Wei-Ning

    2006-04-01

    We present a mathematical model for a dynamic Delphi survey method which takes advantages of Web technology. A comparative study on the performance of the conventional Delphi method and the dynamic Delphi instrument is conducted. It is suggested that a dynamic Delphi survey may form a consensus quickly. However, the result may not be robust due to the judgement leaking issues.

  19. Sequential estimation and satellite data assimilation in meteorology and oceanography

    NASA Technical Reports Server (NTRS)

    Ghil, M.

    1986-01-01

    The central theme of this review article is the role that dynamics plays in estimating the state of the atmosphere and of the ocean from incomplete and noisy data. Objective analysis and inverse methods represent an attempt at relying mostly on the data and minimizing the role of dynamics in the estimation. Four-dimensional data assimilation tries to balance properly the roles of dynamical and observational information. Sequential estimation is presented as the proper framework for understanding this balance, and the Kalman filter as the ideal, optimal procedure for data assimilation. The optimal filter computes forecast error covariances of a given atmospheric or oceanic model exactly, and hence data assimilation should be closely connected with predictability studies. This connection is described, and consequences drawn for currently active areas of the atmospheric and oceanic sciences, namely, mesoscale meteorology, medium and long-range forecasting, and upper-ocean dynamics.

  20. Synthesizing genetic sequential logic circuit with clock pulse generator

    PubMed Central

    2014-01-01

    Background Rhythmic clock widely occurs in biological systems which controls several aspects of cell physiology. For the different cell types, it is supplied with various rhythmic frequencies. How to synthesize a specific clock signal is a preliminary but a necessary step to further development of a biological computer in the future. Results This paper presents a genetic sequential logic circuit with a clock pulse generator based on a synthesized genetic oscillator, which generates a consecutive clock signal whose frequency is an inverse integer multiple to that of the genetic oscillator. An analogous electronic waveform-shaping circuit is constructed by a series of genetic buffers to shape logic high/low levels of an oscillation input in a basic sinusoidal cycle and generate a pulse-width-modulated (PWM) output with various duty cycles. By controlling the threshold level of the genetic buffer, a genetic clock pulse signal with its frequency consistent to the genetic oscillator is synthesized. A synchronous genetic counter circuit based on the topology of the digital sequential logic circuit is triggered by the clock pulse to synthesize the clock signal with an inverse multiple frequency to the genetic oscillator. The function acts like a frequency divider in electronic circuits which plays a key role in the sequential logic circuit with specific operational frequency. Conclusions A cascaded genetic logic circuit generating clock pulse signals is proposed. Based on analogous implement of digital sequential logic circuits, genetic sequential logic circuits can be constructed by the proposed approach to generate various clock signals from an oscillation signal. PMID:24884665

  1. F-k Domain Imaging for Synthetic Aperture Sequential Beamforming.

    PubMed

    Vos, Hendrik J; van Neer, Paul L M J; Mota, Mariana Melo; Verweij, Martin D; van der Steen, Antonius F W; Volker, Arno W F

    2016-01-01

    Spatial resolution in medical ultrasound images is a key component in image quality and an important factor for clinical diagnosis. In early systems, the lateral resolution was optimal in the focus but rapidly decreased outside the focal region. Improvements have been found in, e.g., dynamic-receive beamforming, in which the entire image is focused in receive, but this requires complex processing of element data and is not applicable for mechanical scanning of single-element images. This paper exploits the concept of two-stage beamforming based on virtual source-receivers, which reduces the front-end computational load while maintaining a similar data rate and frame rate compared to dynamic-receive beamforming. We introduce frequency-wavenumber domain data processing to obtain fast second-stage data processing while having similarly high lateral resolution as dynamic-receive beamforming and processing in time-space domain. The technique is very suitable in combination with emerging technologies such as application-specific integrated circuits (ASICs), hand-held devices, and wireless data transfer. The suggested method consists of three steps. In the first step, single-focused RF line data are shifted in time to relocate the focal point to a new origin t' = 0, z' = 0. This new origin is considered as an array of virtual source/receiver pairs, as has been suggested previously in literature. In the second step, the dataset is efficiently processed in the wavenumber-frequency domain to form an image that is in focus throughout its entire depth. In the third step, the data shift is undone to obtain a correct depth axis in the image. The method has been tested first with a single-element scanning system and second in a tissue-mimicking phantom using a linear array. In both setups, the method resulted in a −6-dB lateral point spread function (PSF) which was constant over the entire depth range, and similar to dynamic-receive beamforming and synthetic aperture sequential

  2. Magnetization Dynamics of Organic-based Magnetic Heterostructures

    NASA Astrophysics Data System (ADS)

    Chilcote, Michael; Lu, Yu; Wang, Hailong; Yang, Fengyuan; Johnston-Halperin, Ezekiel

    We present temperature dependent ferromagnetic resonance measurements of both isolated magnetic films and bilayers, including all organic and organic/inorganic hybrid magnetic heterostructures. These results establish organic magnetic heterostructures as an exciting new materials platform for the exploration of the fundamental mechanisms driving magnetic ordering in organic-based materials and promise the extension of organic spintronics into the regime of dynamically-driven spin currents, such as those found in spin pumping. The low cost, low-temperature conformal deposition of organic-based thin film magnets makes them an attractive class of materials for device applications. For example, they offer the potential for novel applications in high frequency magnetoelectronics on flexible substrates. Our materials are of the form M[Acceptor]x (M = transition metal, x ~ 2), exhibit room temperature magnetic ordering, and provide the opportunity to tailor magnetic properties through the selection of the transition metal ions and organic ligands. In particular, we focus on ferrimagnetic films and heterostructures where M = vanadium and the organic ligands are tetracyanoethylene (TCNE), ethyl tricyanoethylene carboxylate (ETCEC), and methyl tricyanoethylene carboxylate (MeTCEC).

  3. Maintain rigid structures in Verlet based Cartesian molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Tao, Peng; Wu, Xiongwu; Brooks, Bernard R.

    2012-10-01

    An algorithm is presented to maintain rigid structures in Verlet based Cartesian molecular dynamics (MD) simulations. After each unconstrained MD step, the coordinates of selected particles are corrected to maintain rigid structures through an iterative procedure of rotation matrix computation. This algorithm, named as SHAPE and implemented in CHARMM program suite, avoids the calculations of Lagrange multipliers, so that the complexity of computation does not increase with the number of particles in a rigid structure. The implementation of this algorithm does not require significant modification of propagation integrator, and can be plugged into any Cartesian based MD integration scheme. A unique feature of the SHAPE method is that it is interchangeable with SHAKE for any object that can be constrained as a rigid structure using multiple SHAKE constraints. Unlike SHAKE, the SHAPE method can be applied to large linear (with three or more centers) and planar (with four or more centers) rigid bodies. Numerical tests with four model systems including two proteins demonstrate that the accuracy and reliability of the SHAPE method are comparable to the SHAKE method, but with much more applicability and efficiency.

  4. Finite-difference-based dynamic modeling of MEMS bridge

    NASA Astrophysics Data System (ADS)

    Michael, Aron; Yu, Kevin; Kwok, Chee Yee

    2005-02-01

    In this paper, we present a finite difference based one-dimensional dynamic modeling, which includes electro-thermal coupled with thermo-mechanical behavior of a multi-layered micro-bridge. The electro-thermal model includes the heat transfer from the joule-heated layer to the other layers, and establishes the transient temperature gradient through the thickness of the bridge. The thermal moment and axial load resulting from the transient temperature gradient are used to couple electro-thermal with thermo-mechanical behavior. The dynamic modeling takes into account buckling, and damping effects, asymmetry residual stresses in the layers, and lateral movement at the support ends. The proposed model is applied to a tri-layer micro-bridge of 1000μm length, made of 2μm silicon dioxide sandwiched in between 2μm thick epi-silicon, and 2μm thick poly silicon, with four 400μm long legs, and springs at the four corners the bridge. The beam, and legs are 40μm, and 10μm wide respectively. Results demonstrate the bi-stability of the structure, and a large movement of 40μm between the up and down stable states can easily be obtained. Application of only 21mA electrical current for 15μs to the legs is required to switch buckled-up position to buckled-down position. An additional trapezoidal waveform electrical current of 100mA amplitude for 4μs, and 100μs falling time needs to be applied for the reverse actuation. The switching speed in both cases is less than 500μs.

  5. Sequentially firing neurons confer flexible timing in neural pattern generators

    SciTech Connect

    Urban, Alexander; Ermentrout, Bard

    2011-05-15

    Neuronal networks exhibit a variety of complex spatiotemporal patterns that include sequential activity, synchrony, and wavelike dynamics. Inhibition is the primary means through which such patterns are implemented. This behavior is dependent on both the intrinsic dynamics of the individual neurons as well as the connectivity patterns. Many neural circuits consist of networks of smaller subcircuits (motifs) that are coupled together to form the larger system. In this paper, we consider a particularly simple motif, comprising purely inhibitory interactions, which generates sequential periodic dynamics. We first describe the dynamics of the single motif both for general balanced coupling (all cells receive the same number and strength of inputs) and then for a specific class of balanced networks: circulant systems. We couple these motifs together to form larger networks. We use the theory of weak coupling to derive phase models which, themselves, have a certain structure and symmetry. We show that this structure endows the coupled system with the ability to produce arbitrary timing relationships between symmetrically coupled motifs and that the phase relationships are robust over a wide range of frequencies. The theory is applicable to many other systems in biology and physics.

  6. Modeling of dynamic hysteresis for grain-oriented laminations using a viscosity-based modified dynamic Jiles-Atherton model

    NASA Astrophysics Data System (ADS)

    Baghel, A. P. S.; Shekhawat, S. K.; Kulkarni, S. V.; Samajdar, I.

    2014-09-01

    Grain-oriented (GO) materials exhibit arbitrary frequency-loss behaviors and anomalies in dynamic hysteresis loop shapes. Significant attempts have been made in the literature to approximate dynamic hysteresis loops using the dynamic Jiles-Atherton (JA) model based Bertotti's approach. Such a model is inefficient in accurate loss computation over a wide range of frequencies and in predictions of correct loop shapes. Moreover, the original static JA model also needs to be improved for accurate prediction of highly steep, gooseneck, and narrow-waist static loops of GO materials. An alternative approach based on magnetic viscosity provides flexibilities to handle indefinite frequency dependence of the losses and to control the anomalous loop shapes. This paper proposes a viscosity-based dynamic JA model which gives accurate prediction of dynamic loops of GO materials. A modified static JA model which considers crystalline and textured structures of GO materials is used to predict static hysteresis loops. The dynamic losses are included in the modified model using the field separation approach. The proposed model is validated using experimental measurements. The computed and measured dynamic loops are in close agreement in the frequency range of 1-200 Hz.

  7. Sequential provisional implant prosthodontics therapy.

    PubMed

    Zinner, Ira D; Markovits, Stanley; Jansen, Curtis E; Reid, Patrick E; Schnader, Yale E; Shapiro, Herbert J

    2012-01-01

    The fabrication and long-term use of first- and second-stage provisional implant prostheses is critical to create a favorable prognosis for function and esthetics of a fixed-implant supported prosthesis. The fixed metal and acrylic resin cemented first-stage prosthesis, as reviewed in Part I, is needed for prevention of adjacent and opposing tooth movement, pressure on the implant site as well as protection to avoid micromovement of the freshly placed implant body. The second-stage prosthesis, reviewed in Part II, should be used following implant uncovering and abutment installation. The patient wears this provisional prosthesis until maturation of the bone and healing of soft tissues. The second-stage provisional prosthesis is also a fail-safe mechanism for possible early implant failures and also can be used with late failures and/or for the necessity to repair the definitive prosthesis. In addition, the screw-retained provisional prosthesis is used if and when an implant requires removal or other implants are to be placed as in a sequential approach. The creation and use of both first- and second-stage provisional prostheses involve a restorative dentist, dental technician, surgeon, and patient to work as a team. If the dentist alone cannot do diagnosis and treatment planning, surgery, and laboratory techniques, he or she needs help by employing the expertise of a surgeon and a laboratory technician. This team approach is essential for optimum results. PMID:23220306

  8. Sequential dehalogenation of chlorinated ethenes

    SciTech Connect

    Barrio-Lage, G.; Parsons, F.Z.; Nassar, R.S.; Lorenzo, P.A.

    1986-01-01

    Reductive dehalogenation of tetra- and trichloroethene to cis- and trans-1,2-dichloroethene in microcosms simulating groundwater environment has previously been demonstrated. In this study, anoxic microcosms containing organic sediment and water were spiked to contain 5 mg/L of one of the following compounds: 1,1-dichloroethene (1,1-DCE), cis-1,2-dichloroethene (CIS), or trans-1,2-dichloroethene (TRANS). After incubation in the dark at 25/sup 0/ C for up to 6 months, contents were analyzed by gas chromatography and verified by gas chromatography/mass spectrometry in an attempt to identify sequential steps in the transformation process. Vinyl chloride (VC) was produced after 1-2 weeks of incubation in all spiked microcosms, but none was observed in sterile and unspiked controls. Chloroethane (CE) was produced only in microcosms spiked with CIS, indicating isomer specificity and the occurrence of mechanisms other than reductive dechlorination. Kinetic parameters associated with the microbial dehalogenation of 1,1-DCE, CIS, and TRANS were calculated. 11 references, 5 figures, 1 table.

  9. Multilevel sequential Monte Carlo samplers

    DOE PAGESBeta

    Beskos, Alexandros; Jasra, Ajay; Law, Kody; Tempone, Raul; Zhou, Yan

    2016-08-24

    Here, we study the approximation of expectations w.r.t. probability distributions associated to the solution of partial differential equations (PDEs); this scenario appears routinely in Bayesian inverse problems. In practice, one often has to solve the associated PDE numerically, using, for instance finite element methods and leading to a discretisation bias, with the step-size level hL. In addition, the expectation cannot be computed analytically and one often resorts to Monte Carlo methods. In the context of this problem, it is known that the introduction of the multilevel Monte Carlo (MLMC) method can reduce the amount of computational effort to estimate expectations, for a given level of error. This is achieved via a telescoping identity associated to a Monte Carlo approximation of a sequence of probability distributions with discretisation levelsmore » $${\\infty}$$ >h0>h1 ...>hL. In many practical problems of interest, one cannot achieve an i.i.d. sampling of the associated sequence of probability distributions. A sequential Monte Carlo (SMC) version of the MLMC method is introduced to deal with this problem. In conclusion, it is shown that under appropriate assumptions, the attractive property of a reduction of the amount of computational effort to estimate expectations, for a given level of error, can be maintained within the SMC context.« less

  10. Sequentially deployable maneuverable tetrahedral beam

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Crawford, R. F. (Inventor)

    1985-01-01

    A tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure is comprised of a number of repeating units of tandem tetralhedral sharing common sides. Fixed length battens are jointed into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons having a mid-point folding hinge. Joints, comprised of gussets pivotabley connected by links, permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The beam is suited to remote actuation. Longerons may be provided with powered mid-point hinges enabling beam erection and packaging under remote control. Providing one or more longerons with powered telescoping segments permits the shape of the beam central axis to be remotely manipulated so that the beam may function as a remote manipulator arm.

  11. Sequentially deployable maneuverable tetrahedral beam

    NASA Astrophysics Data System (ADS)

    Mikulas, M. M., Jr.; Crawford, R. F.

    1985-12-01

    A tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure is comprised of a number of repeating units of tandem tetralhedral sharing common sides. Fixed length battens are jointed into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons having a mid-point folding hinge. Joints, comprised of gussets pivotabley connected by links, permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The beam is suited to remote actuation. Longerons may be provided with powered mid-point hinges enabling beam erection and packaging under remote control. Providing one or more longerons with powered telescoping segments permits the shape of the beam central axis to be remotely manipulated so that the beam may function as a remote manipulator arm.

  12. Ridge-based bias potentials to accelerate molecular dynamics.

    PubMed

    Xiao, Penghao; Duncan, Juliana; Zhang, Liang; Henkelman, Graeme

    2015-12-28

    An effective way to accelerate rare events in molecular dynamics simulations is to apply a bias potential which destabilizes minima without biasing the transitions between stable states. This approach, called hyperdynamics, is limited by our ability to construct general bias potentials without having to understand the reaction mechanisms available to the system, a priori. Current bias potentials are typically constructed in terms of a metric which quantifies the distance that a trajectory deviates from the reactant state minimum. Such metrics include detection of negative curvatures of the potential, an energy increase, or deviations in bond lengths from the minimum. When one of these properties exceeds a critical value, the bias potentials are constructed to approach zero. A problem common to each of these schemes is that their effectiveness decreases rapidly with system size. We attribute this problem to a diminishing volume defined by the metrics around a reactant minimum as compared to the total volume of the reactant state basin. In this work, we mitigate the dimensionality scaling problem by constructing bias potentials that are based upon the distance to the boundary of the reactant basin. This distance is quantified in two ways: (i) by following the minimum mode direction to the reactant boundary and (ii) by training a machine learning algorithm to give an analytic expression for the boundary to which the distance can be calculated. Both of these ridge-based bias potentials are demonstrated to scale qualitatively better with dimensionality than the existing methods. We attribute this improvement to a greater filling fraction of the reactant state using the ridge-based bias potentials as compared to the standard potentials. PMID:26723648

  13. The sequential structure of brain activation predicts skill.

    PubMed

    Anderson, John R; Bothell, Daniel; Fincham, Jon M; Moon, Jungaa

    2016-01-29

    In an fMRI study, participants were trained to play a complex video game. They were scanned early and then again after substantial practice. While better players showed greater activation in one region (right dorsal striatum) their relative skill was better diagnosed by considering the sequential structure of whole brain activation. Using a cognitive model that played this game, we extracted a characterization of the mental states that are involved in playing a game and the statistical structure of the transitions among these states. There was a strong correspondence between this measure of sequential structure and the skill of different players. Using multi-voxel pattern analysis, it was possible to recognize, with relatively high accuracy, the cognitive states participants were in during particular scans. We used the sequential structure of these activation-recognized states to predict the skill of individual players. These findings indicate that important features about information-processing strategies can be identified from a model-based analysis of the sequential structure of brain activation. PMID:26707716

  14. Sequential decision plans, benthic macroinvertebrates, and biological monitoring programs

    NASA Astrophysics Data System (ADS)

    Jackson, John K.; Resh, Vincent H.

    1989-07-01

    A common obstacle to the inclusion of benthic macroinvertebrates in water quality monitoring programs is that numerous sample units must be examined in order to distinguish between impacted and unimpacted conditions, which can add significantly to the total cost of a monitoring program. Sequential decision plans can be used to reduce this cost because the number of sample units needed to classify a site as impacted or unimpacted is reduced by an average of 50%. A plan is created using definitions of unimpacted and impacted conditions, a description of the mathematical distribution of the data, and definitions of acceptable risks of type I and II errors. The applicability of using sequential decision plans and benthic macroinvertebrates in water quality monitoring programs is illustrated with several examples (e.g., identifying moderate and extreme changes in species richness in response to acid mine drainage; assessing the impact of a crude oil contamination on the density of two benthic populations; monitoring the effect of geothermal effluents on species diversity). These examples use data conforming to the negative binomial, Poisson, and normal distributions and define impact as changes in population density, species richness, or species diversity based on empirical data or the economic feasibility of the sequential decision plan. All mathematical formulae and intermediate values are provided for the step-by-step calculation of each sequential decision plan.

  15. Linear State-Space Representation of the Dynamics of Relative Motion, Based on Restricted Three Body Dynamics

    NASA Technical Reports Server (NTRS)

    Luquette, Richard J.; Sanner, Robert M.

    2004-01-01

    Precision Formation Flying is an enabling technology for a variety of proposed space- based observatories, including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), Stellar Imager (SI) and the Terrestrial Planet Finder (TPF). An essential element of the technology is the control algorithm, requiring a clear understanding of the dynamics of relative motion. This paper examines the dynamics of relative motion in the context of the Restricted Three Body Problem (RTBP). The natural dynamics of relative motion are presented in their full nonlinear form. Motivated by the desire to apply linear control methods, the dynamics equations are linearized and presented in state-space form. The stability properties are explored for regions in proximity to each of the libration points in the Earth/Moon - Sun rotating frame. The dynamics of relative motion are presented in both the inertial and rotating coordinate frames.

  16. Linear State-Space Representation of the Dynamics of Relative Motion, Based on Restricted Three Body Dynamics

    NASA Technical Reports Server (NTRS)

    Luquette,Richard J.; Sanner, Robert M.

    2004-01-01

    Precision Formation Flying is an enabling technology for a variety of proposed space-based observatories, including the Micro-Arcsecond X-ray Imaging Mission (MAXIM) , the associated MAXIM pathfinder mission, Stellar Imager (SI) and the Terrestrial Planet Finder (TPF). An essential element of the technology is the control algorithm, requiring a clear understanding of the dynamics of relative motion. This paper examines the dynamics of relative motion in the context of the Restricted Three Body Problem (RTBP). The natural dynamics of relative motion are presented in their full nonlinear form. Motivated by the desire to apply linear control methods, the dynamics equations are linearized and presented in state-space form. The stability properties are explored for regions in proximity to each of the libration points in the Earth/Moon - Sun rotating frame. The dynamics of relative motion are presented in both the inertial and rotating coordinate frames.

  17. Theoretical Shaping of Femtosecond Laser Pulses for Molecular Photodissociation with Control Techniques Based on Ehrenfest's Dynamics and Time-Dependent Density Functional Theory.

    PubMed

    Castro, Alberto

    2016-06-01

    The combination of nonadiabatic Ehrenfest-path molecular dynamics (EMD) based on time-dependent density functional theory (TDDFT) and quantum optimal control formalism (QOCT) was used to optimize the shape of ultra-short laser pulses to achieve photodissociation of a hydrogen molecule and the trihydrogen cation H3 (+) . This work completes a previous one [A. Castro, ChemPhysChem, 2013, 14, 1488-1495], in which the same objective was achieved by demonstrating the combination of QOCT and TDDFT for many-electron systems on static nuclear potentials. The optimization model, therefore, did not include the nuclear movement and the obtained dissociation mechanism could only be sequential: fast laser-assisted electronic excitation to nonbonding states (during which the nuclei are considered to be static), followed by field-free dissociation. Here, in contrast, the optimization was performed with the QOCT constructed on top of the full dynamic model comprised of both electrons and nuclei, as described within EMD based on TDDFT. This is the first numerical demonstration of an optimal control formalism for a hybrid quantum-classical model, that is, a molecular dynamics method. PMID:26945807

  18. Using a Mixed Methods Sequential Design to Identify Factors Associated with African American Mothers' Intention to Vaccinate Their Daughters Aged 9 to 12 for HPV with a Purpose of Informing a Culturally-Relevant, Theory-Based Intervention

    ERIC Educational Resources Information Center

    Cunningham, Jennifer L.

    2013-01-01

    The purpose of this sequential, explanatory mixed methods research study was to understand what factors influenced African American maternal intentions to get their daughters aged 9 years to 12 years vaccinated in Alabama. In the first, quantitative phase of the study, the research questions focused on identifying the predictive power of eleven…

  19. Electron accommodation dynamics in the DNA base thymine

    SciTech Connect

    King, Sarah B.; Yandell, Margaret A.; Kunin, Alice; Stephansen, Anne B.; Yokoi, Yuki; Takayanagi, Toshiyuki; Neumark, Daniel M.

    2015-07-14

    The dynamics of electron attachment to the DNA base thymine are investigated using femtosecond time-resolved photoelectron imaging of the gas phase iodide-thymine (I{sup −}T) complex. An ultraviolet pump pulse ejects an electron from the iodide and prepares an iodine-thymine temporary negative ion that is photodetached with a near-IR probe pulse. The resulting photoelectrons are analyzed with velocity-map imaging. At excitation energies ranging from −120 meV to +90 meV with respect to the vertical detachment energy (VDE) of 4.05 eV for I{sup −}T, both the dipole-bound and valence-bound negative ions of thymine are observed. A slightly longer rise time for the valence-bound state than the dipole-bound state suggests that some of the dipole-bound anions convert to valence-bound species. No evidence is seen for a dipole-bound anion of thymine at higher excitation energies, in the range of 0.6 eV above the I{sup −}T VDE, which suggests that if the dipole-bound anion acts as a “doorway” to the valence-bound anion, it only does so at excitation energies near the VDE of the complex.

  20. Self-diagnosis of smart structures based on dynamical properties

    NASA Astrophysics Data System (ADS)

    Fritzen, C.-P.; Kraemer, P.

    2009-08-01

    When we talk about "smart structures" we can think about different properties and capabilities which make a structure "intelligent" in a certain sense. Originally, the expression "smart" was used in the context that a structure can react and adapt to certain environmental conditions, such as change of shape, compensation of deformations, active vibration damping, etc. Over the last year, the expression "smart" has been extended to the field of structural health monitoring (SHM), where sensor networks, actuators and computational capabilities are used to enable a structure to perform a self-diagnosis with the goal that this structure can release early warnings about a critical health state, locate and classify damage or even to forecast the remaining life-time. This paper intends to give an overview and point out recent developments of vibration-based methods for SHM. All these methods have in common that a structural change due to a damage results in a more or less significant change of the dynamic behavior. For the diagnosis an inverse problem has to be solved. We discuss the use of modal information as well as the direct use of forced and ambient vibrations in the time and frequency domain. Examples from civil and aerospace engineering as well as off-shore wind energy plants show the applicability of these methods.

  1. Molecular dynamics study of surfactant-like peptide based nanostructures.

    PubMed

    Colherinhas, Guilherme; Fileti, Eudes

    2014-10-23

    Surfactant-like peptide (SLP) based nanostructures are investigated using all-atomistic molecular dynamics (MD) simulations. We report structure properties of nanostructures belonging to the ANK peptide group. In particular, the mathematical models for the two A3K membranes, A6K nanotube, and A9K nanorod were developed. Our MD simulation results are consistent with the experimental data, indicating that A3K membranes are stable in two different configurations: (1) SLPs are tilted relative to the normal membrane plane; (2) SLPs are interdigitated. The former configuration is energetically more stable. The cylindrical nanostructures feature a certain order of the A6K peptides. In turn, the A9K nanorod does not exhibit any long-range ordering. Both nanotube and nanorod structure contain large amounts of water inside. Consequently, these nanostructures behave similar to hydrogels. This property may be important in the context of biotechnology. Binding energy analysis-in terms of Coulomb and van der Waals contributions-unveils an increase as the peptide size increases. The electrostatic interaction constitutes 70-75% of the noncovalent attraction energy between SLPs. The nanotubular structures are notably stable, confirming that A6K peptides preferentially form nanotubes and A9K peptides preferentially form nanorods. PMID:25264942

  2. Dynamic response of reverse Taylor impact based on DIC technology

    NASA Astrophysics Data System (ADS)

    Liu, Jiancheng; Pi, Aiguo; Wu, Haijun; Huang, Fenglei

    2015-09-01

    Reverse ballistic impact test, which can obtain the response data of rod/projectile more comprehensive and quantitative than forward impact test, was widely used for the measurement of material dynamic and structure response. Based on the DIC technology and traditional optical measurement (high-speed camera measurement), the Taylor experiment of reverse ballistic with different length-diameter ratio and different impact velocities were carried out by 57 mm compression-shear type light-gas gun, which provides the instantaneous response data of the Taylor rod in microsecond level. Then, the transient structural deformation of the specimen and the characteristics of plastic wave propagation were analysed by DIC technology and compared with traditional optical measurement. Applying the theory of reverse Taylor impact deformation and combining with the simulation results by LS-DYNA, the rules of structure deformation and plastic wave propagation were obtained. The method above can be applied for the structure response of penetrator under the condition of reverse ballistic penetration.

  3. Applicability of random sequential adsorption algorithm for simulation of surface plasma polishing kinetics

    NASA Astrophysics Data System (ADS)

    Minárik, Stanislav; Vaňa, Dušan

    2015-11-01

    Applicability of random sequential adsorption (RSA) model for the material removal during a surface plasma polishing is discussed. The mechanical nature of plasma polishing process is taken into consideration in modified version of RSA model. During the plasma polishing the surface layer is aligned such that molecules of material are removed from the surface mechanically as a consequence of the surface deformation induced by plasma particles impact. We propose modification of RSA technique to describe the reduction of material on the surface provided that sequential character of molecules release from the surface is maintained throughout the polishing process. This empirical model is able to estimate depth profile of material density on the surface during the plasma polishing. We have shown that preliminary results obtained from this model are in good agreement with experimental results. We believe that molecular dynamics simulation of the polishing process, possibly also other types of surface treatment, can be based on this model. However influence of material parameters and processing conditions (including plasma characteristics) must be taken into account using appropriate model variables.

  4. The nth root of sequential effect algebras

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Wu, Junde

    2010-06-01

    In 2005, Gudder [Int. J. Theor. Phys. 44, 2219 (2005)] presented 25 problems of sequential effect algebras, the 20th problem asked: In a sequential effect algebra, if the square root of some element exists, is it unique? In this paper, we show that for each given positive integer n >1, there is a sequential effect algebra such that the nth root of its some element c is not unique, and the nth root of c is not the kth root of c (k

  5. Dynamic Light Scattering Based Microelectrophoresis: Main Prospects and Limitations

    PubMed Central

    Uskoković, Vuk

    2013-01-01

    Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation averaging, are revisited in this work. Along with that, the main prospects of these two analytical methods are mentioned. A detailed review of the role of zeta potential in processes of biochemical nature is given too. It is argued that although zeta potential has been used as one of the main parameters in controlling the stability of colloidal dispersions, its application potentials are much broader. Manipulating surface charges of interacting species in designing complex soft matter morphologies using the concept of zeta potential, intensively investigated recently, is given as one of the examples. Branching out from the field of colloid chemistry, DLS and zeta potential analyses are now increasingly finding application in drug delivery, biotechnologies, physical chemistry of nanoscale phenomena and other research fields that stand on the frontier of the contemporary science. Coupling the DLS-based microelectrophoretic systems with complementary characterization methods is mentioned as one of the prosperous paths for increasing the information output of these two analytical techniques. PMID:23904690

  6. Modeled F region response to auroral dynamics based up dynamics explorer auroral observations

    SciTech Connect

    Sojka, J.J.; Schunk, R.W. ); Craven, J.D.; Frank, L.A.; Sharber, J.; Winningham, J.D.

    1989-07-01

    Auroral images from the Dynamiccs Explorer 1 (DE 1) scanning auroral imager have been combined with in situ auroral precipitation data from the DE 2 low altitude plasma instrument to form a time-dependent global auroral energy flux model. This model has both good time (12 min) and spatial (100 km) resolution compared to that currently available for global scale ionospheric and thermospheric modeling. The development and comparison of this model with others are discussed. Data from an aurorally active period, November 25, 1981, are presented and used as a case study for this model. Using a global ionospheric model, the effect of the DE auroral model is contrasted with that of a conventional empirical auroral energy flux model. Major differences in the modeled {ital F} region ionosphere are predicted from this comparative study. Specifically, {ital F} region densities differ by factors of two to four, while density boundary locations differ by up to 5{degree} in latitude. The results indicate that pixel size'' auroral fine-structure must be included in the global ionosphere and thermosphere models when they are tested against specific ground-based or satellite data sets if an unambiguous result is to be obtained. The longer time constants of the {ital F} region are not enough to smooth-out the auroral (spatial and temporal) dynamics. {copyright} American Geophysical Union 1989

  7. Dynamic biogas upgrading based on the Sabatier process: thermodynamic and dynamic process simulation.

    PubMed

    Jürgensen, Lars; Ehimen, Ehiaze Augustine; Born, Jens; Holm-Nielsen, Jens Bo

    2015-02-01

    This study aimed to investigate the feasibility of substitute natural gas (SNG) generation using biogas from anaerobic digestion and hydrogen from renewable energy systems. Using thermodynamic equilibrium analysis, kinetic reactor modeling and transient simulation, an integrated approach for the operation of a biogas-based Sabatier process was put forward, which was then verified using a lab scale heterogenous methanation reactor. The process simulation using a kinetic reactor model demonstrated the feasibility of the production of SNG at gas grid standards using a single reactor setup. The Wobbe index, CO2 content and calorific value were found to be controllable by the H2/CO2 ratio fed the methanation reactor. An optimal H2/CO2 ratio of 3.45-3.7 was seen to result in a product gas with high calorific value and Wobbe index. The dynamic reactor simulation verified that the process start-up was feasible within several minutes to facilitate surplus electricity use from renewable energy systems. PMID:25453430

  8. Dynamic optimization methodology based on subgrid-scale dissipation for large eddy simulation

    NASA Astrophysics Data System (ADS)

    Yu, Changping; Xiao, Zuoli; Li, Xinliang

    2016-01-01

    A dynamic procedure based on subgrid-scale dissipation is proposed for large eddy simulation of turbulent flows. In the new method, the model coefficients are determined by minimizing the square error of the resolved dissipation rate based on the Germano identity. A dynamic two-term mixed model is tested and evaluated both a priori and a posteriori in simulations of homogeneous and isotropic turbulence. The new dynamic procedure proves to be more effective to optimize the model coefficients as compared with traditional method. The corresponding dynamic mixed model can predict the physical quantities more accurately than traditional dynamic mixed model.

  9. Endogenous Sequential Cortical Activity Evoked by Visual Stimuli

    PubMed Central

    Miller, Jae-eun Kang; Hamm, Jordan P.; Jackson, Jesse; Yuste, Rafael

    2015-01-01

    Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

  10. Finger Tendon Travel Associated with Sequential Trigger Nail Gun Use

    PubMed Central

    Lowe, Brian; Albers, James; Hudock, Stephen; Krieg, Edward

    2015-01-01

    TECHNICAL ABSTRACT Background Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers have been shown to be a safer alternative to contact actuation triggers because they reduce traumatic injury risk. However, the sequential actuation trigger must be depressed for each individual nail fired as opposed to the contact actuation trigger, which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the sequential actuation trigger. Purpose This study developed a method to predict cumulative finger flexor tendon travel associated with the sequential actuation trigger nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood-frame construction tasks. Methods Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks–wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. Results Finger flexor tendon travel was attributable mostly to proximal interphalangeal and distal interphalangeal joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high-production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1700 trigger presses/day). Conclusion and Applications These results suggest that exposure to finger tendon travel from sequential actuation trigger nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk. PMID

  11. Research on parallel algorithm for sequential pattern mining

    NASA Astrophysics Data System (ADS)

    Zhou, Lijuan; Qin, Bai; Wang, Yu; Hao, Zhongxiao

    2008-03-01

    Sequential pattern mining is the mining of frequent sequences related to time or other orders from the sequence database. Its initial motivation is to discover the laws of customer purchasing in a time section by finding the frequent sequences. In recent years, sequential pattern mining has become an important direction of data mining, and its application field has not been confined to the business database and has extended to new data sources such as Web and advanced science fields such as DNA analysis. The data of sequential pattern mining has characteristics as follows: mass data amount and distributed storage. Most existing sequential pattern mining algorithms haven't considered the above-mentioned characteristics synthetically. According to the traits mentioned above and combining the parallel theory, this paper puts forward a new distributed parallel algorithm SPP(Sequential Pattern Parallel). The algorithm abides by the principal of pattern reduction and utilizes the divide-and-conquer strategy for parallelization. The first parallel task is to construct frequent item sets applying frequent concept and search space partition theory and the second task is to structure frequent sequences using the depth-first search method at each processor. The algorithm only needs to access the database twice and doesn't generate the candidated sequences, which abates the access time and improves the mining efficiency. Based on the random data generation procedure and different information structure designed, this paper simulated the SPP algorithm in a concrete parallel environment and implemented the AprioriAll algorithm. The experiments demonstrate that compared with AprioriAll, the SPP algorithm had excellent speedup factor and efficiency.

  12. An object-based compression system for a class of dynamic image-based representations

    NASA Astrophysics Data System (ADS)

    Wu, Qing; Ng, King-To; Chan, Shing-Chow; Shum, Heung-Yeung

    2005-07-01

    This paper proposes a new object-based compression system for a class of dynamic image-based representations called plenoptic videos (PVs). PVs are simplified dynamic light fields, where the videos are taken at regularly spaced locations along line segments instead of a 2-D plane. The proposed system employs an object-based approach, where objects at different depth values are segmented to improve the rendering quality as in the pop-up light fields. Furthermore, by coding the plenoptic video at the object level, desirable functionalities such as scalability of contents, error resilience, and interactivity with individual IBR objects can be achieved. Besides supporting the coding of the texture and binary shape maps for IBR objects with arbitrary shapes, the proposed system also supports the coding of gray-scale alpha maps as well as geometry information in the form of depth maps to respectively facilitate the matting and rendering of the IBR objects. To improve the coding performance, the proposed compression system exploits both the temporal redundancy and spatial redundancy among the video object streams in the PV by employing disparity-compensated prediction or spatial prediction in its texture, shape and depth coding processes. To demonstrate the principle and effectiveness of the proposed system, a multiple video camera system was built and experimental results show that considerable improvements in coding performance are obtained for both synthetic scene and real scene, while supporting the stated object-based functionalities.

  13. Bilingual control: sequential memory in language switching.

    PubMed

    Declerck, Mathieu; Philipp, Andrea M; Koch, Iring

    2013-11-01

    To investigate bilingual language control, prior language switching studies presented visual objects, which had to be named in different languages, typically indicated by a visual cue. The present study examined language switching of predictable responses by introducing a novel sequence-based language switching paradigm. In 4 experiments, sequential responses (i.e., weekdays, numbers or new sequences) and an alternating language sequence (e.g., L1-L1-L2-L2) were implemented, both of which were memory based. Our data revealed switch costs, showing that a language switch is associated with worse performance compared with a language repetition, and mixing costs, which constitutes the performance difference between pure and mixed language blocks, even while producing entirely predictable responses (i.e., language and concept). Additionally, we found these switch costs with overlearned and new sequences and found that switch costs were reduced with longer preparation time. The obtained data are consistent with a proactive interference account, such as the inhibitory control model. PMID:23773181

  14. Sequential Changepoint Approach for Online Community Detection

    NASA Astrophysics Data System (ADS)

    Marangoni-Simonsen, David; Xie, Yao

    2015-08-01

    We present new algorithms for detecting the emergence of a community in large networks from sequential observations. The networks are modeled using Erdos-Renyi random graphs with edges forming between nodes in the community with higher probability. Based on statistical changepoint detection methodology, we develop three algorithms: the Exhaustive Search (ES), the mixture, and the Hierarchical Mixture (H-Mix) methods. Performance of these methods is evaluated by the average run length (ARL), which captures the frequency of false alarms, and the detection delay. Numerical comparisons show that the ES method performs the best; however, it is exponentially complex. The mixture method is polynomially complex by exploiting the fact that the size of the community is typically small in a large network. However, it may react to a group of active edges that do not form a community. This issue is resolved by the H-Mix method, which is based on a dendrogram decomposition of the network. We present an asymptotic analytical expression for ARL of the mixture method when the threshold is large. Numerical simulation verifies that our approximation is accurate even in the non-asymptotic regime. Hence, it can be used to determine a desired threshold efficiently. Finally, numerical examples show that the mixture and the H-Mix methods can both detect a community quickly with a lower complexity than the ES method.

  15. Multistability for Delayed Neural Networks via Sequential Contracting.

    PubMed

    Cheng, Chang-Yuan; Lin, Kuang-Hui; Shih, Chih-Wen; Tseng, Jui-Pin

    2015-12-01

    In this paper, we explore a variety of new multistability scenarios in the general delayed neural network system. Geometric structure embedded in equations is exploited and incorporated into the analysis to elucidate the underlying dynamics. Criteria derived from different geometric configurations lead to disparate numbers of equilibria. A new approach named sequential contracting is applied to conclude the global convergence to multiple equilibrium points of the system. The formulation accommodates both smooth sigmoidal and piecewise-linear activation functions. Several numerical examples illustrate the present analytic theory. PMID:25751881

  16. Multiple fault condition recognition of gearbox with sequential hypothesis test

    NASA Astrophysics Data System (ADS)

    Chen, Hanxin; Shang, Yunfei; Sun, Kui

    2013-11-01

    A novel method for the fault condition recognition in which the recognition system interrogates a propagation channel adaptively and intelligently by using the available data is proposed based on sequential hypothesis testing. The waveform of the data in the propagation channel for the fault condition recognition is designed with the kurtosis of the measured data in time domain. The sequential hypothesis testing framework is proposed when hard decisions are made with adequate confidence. The distinguished characteristic of the channel recognition is that it operates in a closed loop and makes constant optimization in response to its changing understanding of the channel. The fault condition recognition of the gearbox is to update the multiple target hypothesis/class based on the measured data, customize waveform as the class probabilities changes, and make conclusion when the sufficient understanding of the propagation channel is achieved.

  17. Adaptive Methods within a Sequential Bayesian Approach for Structural Health Monitoring

    NASA Astrophysics Data System (ADS)

    Huff, Daniel W.

    Structural integrity is an important characteristic of performance for critical components used in applications such as aeronautics, materials, construction and transportation. When appraising the structural integrity of these components, evaluation methods must be accurate. In addition to possessing capability to perform damage detection, the ability to monitor the level of damage over time can provide extremely useful information in assessing the operational worthiness of a structure and in determining whether the structure should be repaired or removed from service. In this work, a sequential Bayesian approach with active sensing is employed for monitoring crack growth within fatigue-loaded materials. The monitoring approach is based on predicting crack damage state dynamics and modeling crack length observations. Since fatigue loading of a structural component can change while in service, an interacting multiple model technique is employed to estimate probabilities of different loading modes and incorporate this information in the crack length estimation problem. For the observation model, features are obtained from regions of high signal energy in the time-frequency plane and modeled for each crack length damage condition. Although this observation model approach exhibits high classification accuracy, the resolution characteristics can change depending upon the extent of the damage. Therefore, several different transmission waveforms and receiver sensors are considered to create multiple modes for making observations of crack damage. Resolution characteristics of the different observation modes are assessed using a predicted mean squared error criterion and observations are obtained using the predicted, optimal observation modes based on these characteristics. Calculation of the predicted mean square error metric can be computationally intensive, especially if performed in real time, and an approximation method is proposed. With this approach, the real time

  18. Partition algebraic design of asynchronous sequential circuits

    NASA Technical Reports Server (NTRS)

    Maki, Gary K.; Chen, Kristen Q.; Gopalakrishnan, Suresh K.

    1993-01-01

    Tracey's Theorem has long been recognized as essential in generating state assignments for asynchronous sequential circuits. This paper shows that partitioning variables derived from Tracey's Theorem also has a significant impact in generating the design equations. Moreover, this theorem is important to the fundamental understanding of asynchronous sequential operation. The results of this work simplify asynchronous logic design. Moreover, detection of safe circuits is made easier.

  19. Automated ILA design for synchronous sequential circuits

    NASA Technical Reports Server (NTRS)

    Liu, M. N.; Liu, K. Z.; Maki, G. K.; Whitaker, S. R.

    1991-01-01

    An iterative logic array (ILA) architecture for synchronous sequential circuits is presented. This technique utilizes linear algebra to produce the design equations. The ILA realization of synchronous sequential logic can be fully automated with a computer program. A programmable design procedure is proposed to fullfill the design task and layout generation. A software algorithm in the C language has been developed and tested to generate 1 micron CMOS layouts using the Hewlett-Packard FUNGEN module generator shell.

  20. Ultrafast image-based dynamic light scattering for nanoparticle sizing.

    PubMed

    Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu

    2015-11-01

    An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing. PMID:26628172