WorldWideScience

Sample records for adaptive importance sampling

  1. Adaptive importance sampling for control and inference

    OpenAIRE

    Kappen, Hilbert Johan; Ruiz, Hans Christian

    2015-01-01

    Path integral (PI) control problems are a restricted class of non-linear control problems that can be solved formally as a Feyman-Kac path integral and can be estimated using Monte Carlo sampling. In this contribution we review path integral control theory in the finite horizon case. We subsequently focus on the problem how to compute and represent control solutions. Within the PI theory, the question of how to compute becomes the question of importance sampling. Efficient importance samplers...

  2. Adaptive importance sampling of random walks on continuous state spaces

    Energy Technology Data Exchange (ETDEWEB)

    Baggerly, K.; Cox, D.; Picard, R.

    1998-11-01

    The authors consider adaptive importance sampling for a random walk with scoring in a general state space. Conditions under which exponential convergence occurs to the zero-variance solution are reviewed. These results generalize previous work for finite, discrete state spaces in Kollman (1993) and in Kollman, Baggerly, Cox, and Picard (1996). This paper is intended for nonstatisticians and includes considerable explanatory material.

  3. AIS-BN: An Adaptive Importance Sampling Algorithm for Evidential Reasoning in Large Bayesian Networks

    CERN Document Server

    Cheng, J; 10.1613/jair.764

    2011-01-01

    Stochastic sampling algorithms, while an attractive alternative to exact algorithms in very large Bayesian network models, have been observed to perform poorly in evidential reasoning with extremely unlikely evidence. To address this problem, we propose an adaptive importance sampling algorithm, AIS-BN, that shows promising convergence rates even under extreme conditions and seems to outperform the existing sampling algorithms consistently. Three sources of this performance improvement are (1) two heuristics for initialization of the importance function that are based on the theoretical properties of importance sampling in finite-dimensional integrals and the structural advantages of Bayesian networks, (2) a smooth learning method for the importance function, and (3) a dynamic weighting function for combining samples from different stages of the algorithm. We tested the performance of the AIS-BN algorithm along with two state of the art general purpose sampling algorithms, likelihood weighting (Fung and Chang...

  4. An adaptive importance sampling algorithm for Bayesian inversion with multimodal distributions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weixuan [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Lin, Guang, E-mail: guanglin@purdue.edu [Department of Mathematics and School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States)

    2015-08-01

    Parametric uncertainties are encountered in the simulations of many physical systems, and may be reduced by an inverse modeling procedure that calibrates the simulation results to observations on the real system being simulated. Following Bayes' rule, a general approach for inverse modeling problems is to sample from the posterior distribution of the uncertain model parameters given the observations. However, the large number of repetitive forward simulations required in the sampling process could pose a prohibitive computational burden. This difficulty is particularly challenging when the posterior is multimodal. We present in this paper an adaptive importance sampling algorithm to tackle these challenges. Two essential ingredients of the algorithm are: 1) a Gaussian mixture (GM) model adaptively constructed as the proposal distribution to approximate the possibly multimodal target posterior, and 2) a mixture of polynomial chaos (PC) expansions, built according to the GM proposal, as a surrogate model to alleviate the computational burden caused by computational-demanding forward model evaluations. In three illustrative examples, the proposed adaptive importance sampling algorithm demonstrates its capabilities of automatically finding a GM proposal with an appropriate number of modes for the specific problem under study, and obtaining a sample accurately and efficiently representing the posterior with limited number of forward simulations.

  5. A Class of Adaptive Importance Sampling Weighted EM Algorithms for Efficient and Robust Posterior and Predictive Simulation

    OpenAIRE

    Hoogerheide, L.F.; Opschoor, A.; Dijk, van, Nico M.

    2012-01-01

    This discussion paper was published in the Journal of Econometrics (2012). Vol. 171(2), 101-120. A class of adaptive sampling methods is introduced for efficient posterior and predictive simulation. The proposed methods are robust in the sense that they can handle target distributions that exhibit non-elliptical shapes such as multimodality and skewness. The basic method makes use of sequences of importance weighted Expectation Maximization steps in order to efficiently construct a mixture of...

  6. Network and adaptive sampling

    CERN Document Server

    Chaudhuri, Arijit

    2014-01-01

    Combining the two statistical techniques of network sampling and adaptive sampling, this book illustrates the advantages of using them in tandem to effectively capture sparsely located elements in unknown pockets. It shows how network sampling is a reliable guide in capturing inaccessible entities through linked auxiliaries. The text also explores how adaptive sampling is strengthened in information content through subsidiary sampling with devices to mitigate unmanageable expanding sample sizes. Empirical data illustrates the applicability of both methods.

  7. ADAPTIVE ANNEALED IMPORTANCE SAMPLING FOR MULTIMODAL POSTERIOR EXPLORATION AND MODEL SELECTION WITH APPLICATION TO EXTRASOLAR PLANET DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin, E-mail: bins@ieee.org [School of Computer Science and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China)

    2014-07-01

    We describe an algorithm that can adaptively provide mixture summaries of multimodal posterior distributions. The parameter space of the involved posteriors ranges in size from a few dimensions to dozens of dimensions. This work was motivated by an astrophysical problem called extrasolar planet (exoplanet) detection, wherein the computation of stochastic integrals that are required for Bayesian model comparison is challenging. The difficulty comes from the highly nonlinear models that lead to multimodal posterior distributions. We resort to importance sampling (IS) to estimate the integrals, and thus translate the problem to be how to find a parametric approximation of the posterior. To capture the multimodal structure in the posterior, we initialize a mixture proposal distribution and then tailor its parameters elaborately to make it resemble the posterior to the greatest extent possible. We use the effective sample size (ESS) calculated based on the IS draws to measure the degree of approximation. The bigger the ESS is, the better the proposal resembles the posterior. A difficulty within this tailoring operation lies in the adjustment of the number of mixing components in the mixture proposal. Brute force methods just preset it as a large constant, which leads to an increase in the required computational resources. We provide an iterative delete/merge/add process, which works in tandem with an expectation-maximization step to tailor such a number online. The efficiency of our proposed method is tested via both simulation studies and real exoplanet data analysis.

  8. AND/OR Importance Sampling

    OpenAIRE

    Gogate, Vibhav; Dechter, Rina

    2012-01-01

    The paper introduces AND/OR importance sampling for probabilistic graphical models. In contrast to importance sampling, AND/OR importance sampling caches samples in the AND/OR space and then extracts a new sample mean from the stored samples. We prove that AND/OR importance sampling may have lower variance than importance sampling; thereby providing a theoretical justification for preferring it over importance sampling. Our empirical evaluation demonstrates that AND/OR importance sampling is ...

  9. Importance sampling for characterizing STAP detectors

    NARCIS (Netherlands)

    Srinivasan, R.; Rangaswamy, M.

    2007-01-01

    This paper describes the development of adaptive importance sampling techniques for estimating false alarm probabilities of detectors that use space-time adaptive processing (STAP) algorithms. Fast simulation using importance sampling methods has been notably successful in the study of conventional

  10. Adaptively biased sequential importance sampling for rare events in reaction networks with comparison to exact solutions from finite buffer dCME method.

    Science.gov (United States)

    Cao, Youfang; Liang, Jie

    2013-07-14

    Critical events that occur rarely in biological processes are of great importance, but are challenging to study using Monte Carlo simulation. By introducing biases to reaction selection and reaction rates, weighted stochastic simulation algorithms based on importance sampling allow rare events to be sampled more effectively. However, existing methods do not address the important issue of barrier crossing, which often arises from multistable networks and systems with complex probability landscape. In addition, the proliferation of parameters and the associated computing cost pose significant problems. Here we introduce a general theoretical framework for obtaining optimized biases in sampling individual reactions for estimating probabilities of rare events. We further describe a practical algorithm called adaptively biased sequential importance sampling (ABSIS) method for efficient probability estimation. By adopting a look-ahead strategy and by enumerating short paths from the current state, we estimate the reaction-specific and state-specific forward and backward moving probabilities of the system, which are then used to bias reaction selections. The ABSIS algorithm can automatically detect barrier-crossing regions, and can adjust bias adaptively at different steps of the sampling process, with bias determined by the outcome of exhaustively generated short paths. In addition, there are only two bias parameters to be determined, regardless of the number of the reactions and the complexity of the network. We have applied the ABSIS method to four biochemical networks: the birth-death process, the reversible isomerization, the bistable Schlögl model, and the enzymatic futile cycle model. For comparison, we have also applied the finite buffer discrete chemical master equation (dCME) method recently developed to obtain exact numerical solutions of the underlying discrete chemical master equations of these problems. This allows us to assess sampling results objectively

  11. Fuzzy adaptive importance sampling method based on MCMC%基于MCMC的模糊自适应重要抽样法

    Institute of Scientific and Technical Information of China (English)

    王进玲; 曾声奎; 马纪明

    2012-01-01

    The traditional adaptive importance sampling method based on Markov chain Monte Carlo (MC-MC) can only be applied to the system of determined failure domain but not to the gradual structure system of fuzzy failure domain. A new fuzzy adaptive importance sampling method based on MCMC is proposed. Firstly, the Markov chain samples are constructed according to Metropolis algorithm from the initial sample in the failure domain. Then a kernel sampling probability density function is obtained by adaptive kernel density estimation and the importance sampling is carried out. Finally, the fuzzy failure domain is discretized to compute the fuzzy failure probability. This approach solves the problems that the performance reliability of gradual structure systems is hard to be analyzed through simulation, and the efficiency of simulation is very low. The feasibility and effectiveness of this method are demonstrated by the case of the actuator system.%针对传统的基于马尔可夫链蒙特卡罗(Markov chain Monte Carlo,MCMC)的自适应重要抽样法只适用于失效边界确定的系统,而不适用于失效域模糊的渐变结构系统问题,提出基于MCMC的模糊自适应重要抽样法.首先从模糊失效域内的某个初始点出发,根据Metropolis准则构造马尔可夫模拟样本点;然后利用自适应核密度估计构建核抽样概率密度函数并进行重要抽样;最后离散化模糊失效域以计算系统的模糊失效概率.该方法合理地解决了以往渐变结构系统性能可靠性难以仿真分析及仿真效率低的难题,具有较高的仿真效率和精度.应用舵机案例对方法的适用性及高效性进行了验证.

  12. Adaptive sampling for noisy problems

    Energy Technology Data Exchange (ETDEWEB)

    Cantu-Paz, E

    2004-03-26

    The usual approach to deal with noise present in many real-world optimization problems is to take an arbitrary number of samples of the objective function and use the sample average as an estimate of the true objective value. The number of samples is typically chosen arbitrarily and remains constant for the entire optimization process. This paper studies an adaptive sampling technique that varies the number of samples based on the uncertainty of deciding between two individuals. Experiments demonstrate the effect of adaptive sampling on the final solution quality reached by a genetic algorithm and the computational cost required to find the solution. The results suggest that the adaptive technique can effectively eliminate the need to set the sample size a priori, but in many cases it requires high computational costs.

  13. 混合变量系统基于MCMC的自适应重要抽样法%Adaptive Importance Sampling of Hybrid Variable Systems Based on MCMC

    Institute of Scientific and Technical Information of China (English)

    王进玲; 曾声奎; 马纪明; 庞怡

    2012-01-01

    The occurrence of key failures in a system may cause the system to degrade into different discrete states of performance. The classical importance sampling method based on Markov chain Monte Carlo (MCMC) can only be applied to a continuous variable system and cannot resolve the problem of mixed systems including discrete variables. Therefore, an improved adaptive importance sampling method based on MCMC is proposed to support the efficient simulation of system performance reliability. First, a failure space is constructed by combining different failure domains, and Markov simulation samples are achieved by the initial sample wandering in the failure space. Second, with a comprehensive consideration of continuous and discrete variables, a hybrid sampling density function is obtained through kernel density evaluation. Then, importance sampling simulation is operated according to the last hybrid sampling density function and the performance reliability is computed. Finally, the simulation efficiency is analyzed in theory. The validity and high efficiency of the proposed method are demonstrated by the case of an electro-hydrostatic actuator (EHA) system.%系统关键故障的发生,会导致系统处于各种离散性能降级状态.针对传统的基于马尔可夫链蒙特卡罗( Markov chain Monte Carlo,MCMC)的自适应重要抽样法只适用于连续变量系统的不足,提出考虑混合变量的基于MCMC的自适应重要抽样法,以支持系统性能可靠性的高效仿真.该方法首先将由关键故障产生的不同失效域组成失效空间,并通过初始样本点在失效空间中随机游走构造马尔可夫链模拟样本;然后综合考虑连续变量与离散变量,利用核密度估计构建混合核抽样密度函数;再根据该密度函数进行重要抽样仿真并计算系统的性能可靠性;最后对该方法的仿真效率进行理论分析.通过电液舵机(Electro-Hydrostatic Actuator,EHA)案例对方法的正确性和仿真效率进行验证.

  14. Importance Sampling for the Infinite Sites Model*

    OpenAIRE

    Hobolth, Asger; Uyenoyama, Marcy K; Wiuf, Carsten

    2008-01-01

    Importance sampling or Markov Chain Monte Carlo sampling is required for state-of-the-art statistical analysis of population genetics data. The applicability of these sampling-based inference techniques depends crucially on the proposal distribution. In this paper, we discuss importance sampling for the infinite sites model. The infinite sites assumption is attractive because it constraints the number of possible genealogies, thereby allowing for the analysis of larger data sets. We recall th...

  15. Adaptive sampling algorithm for detection of superpoints

    Institute of Scientific and Technical Information of China (English)

    CHENG Guang; GONG Jian; DING Wei; WU Hua; QIANG ShiQiang

    2008-01-01

    The superpoints are the sources (or the destinations) that connect with a great deal of destinations (or sources) during a measurement time interval, so detecting the superpoints in real time is very important to network security and management. Previous algorithms are not able to control the usage of the memory and to deliver the desired accuracy, so it is hard to detect the superpoints on a high speed link in real time. In this paper, we propose an adaptive sampling algorithm to detect the superpoints in real time, which uses a flow sample and hold module to reduce the detection of the non-superpoints and to improve the measurement accuracy of the superpoints. We also design a data stream structure to maintain the flow records, which compensates for the flow Hash collisions statistically. An adaptive process based on different sampling probabilities is used to maintain the recorded IP ad dresses in the limited memory. This algorithm is compared with the other algo rithms by analyzing the real network trace data. Experiment results and mathematic analysis show that this algorithm has the advantages of both the limited memory requirement and high measurement accuracy.

  16. Importance sampling the Rayleigh phase function

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall

    2011-01-01

    Rayleigh scattering is used frequently in Monte Carlo simulation of multiple scattering. The Rayleigh phase function is quite simple, and one might expect that it should be simple to importance sample it efficiently. However, there seems to be no one good way of sampling it in the literature....... This paper provides the details of several different techniques for importance sampling the Rayleigh phase function, and it includes a comparison of their performance as well as hints toward efficient implementation....

  17. An Adaptive Importance Sampling Theory Based on The Generalized Genetic Algorithm%基于广义遗传算法的自适应重要抽样理论

    Institute of Scientific and Technical Information of China (English)

    董聪; 郭晓华

    2000-01-01

    In the present paper,using the generalized genetic algorithm,the problem of finding out all design points in the case of generalized multiple design point is solved,establishing recursion-type bound-and-classification algorithm,the problem of reducing and synthesizing generaliged multiple design points is also solved.The present paper shows that the adaptive importance sampling theory based on the generalized genetic algorithm is an more efficient tool for the reliability simulation of nonlinear sys-tems.

  18. Importance sampling for NMF class of STAP detectors

    NARCIS (Netherlands)

    Anitori, L.; Srinivasan, R.; Rangaswamy, M.

    2006-01-01

    Importance sampling (IS) techniques are applied to space-time adaptive processing (STAP) radar detection algorithms for performance characterization via fast estimation of false alarm probabilities (FAP’s). The work here builds on and extends the initial thrust in this area provided in a recent pape

  19. Better Confidence Intervals for Importance Sampling

    OpenAIRE

    HALIS SAK; WOLFGANG HÖRMANN; JOSEF LEYDOLD

    2010-01-01

    It is well known that for highly skewed distributions the standard method of using the t statistic for the confidence interval of the mean does not give robust results. This is an important problem for importance sampling (IS) as its final distribution is often skewed due to a heavy tailed weight distribution. In this paper, we first explain Hall's transformation and its variants to correct the confidence interval of the mean and then evaluate the performance of these methods for two numerica...

  20. Importance Sampling for Stochastic Timed Automata

    DEFF Research Database (Denmark)

    Jegourel, Cyrille; Larsen, Kim Guldstrand; Legay, Axel

    2016-01-01

    We present an importance sampling framework that combines symbolic analysis and simulation to estimate the probability of rare reachability properties in stochastic timed automata. By means of symbolic exploration, our framework first identifies states that cannot reach the goal. A state...

  1. Explaining Adaptive Radial-Based Direction Sampling

    NARCIS (Netherlands)

    L. Bauwens (Luc); C.S. Bos (Charles); H.K. van Dijk (Herman); R.D. van Oest (Rutger)

    2003-01-01

    textabstractIn this short paper we summarize the computational steps of Adaptive Radial-Based Direction Sampling (ARDS), which can be used for Bayesian analysis of ill behaved target densities. We consider one simulation experiment in order to illustrate the good performance of ARDS relative to the

  2. Sequential adaptive compressed sampling via Huffman codes

    CERN Document Server

    Aldroubi, Akram; Zarringhalam, Kourosh

    2008-01-01

    There are two main approaches in compressed sensing: the geometric approach and the combinatorial approach. In this paper we introduce an information theoretic approach and use results from the theory of Huffman codes to construct a sequence of binary sampling vectors to determine a sparse signal. Unlike other approaches, our approach is adaptive in the sense that each sampling vector depends on the previous sample. The number of measurements we need for a k-sparse vector in n-dimensional space is no more than O(k log n) and the reconstruction is O(k).

  3. Adaptive Rate Sampling and Filtering Based on Level Crossing Sampling

    Directory of Open Access Journals (Sweden)

    Saeed Mian Qaisar

    2009-01-01

    Full Text Available The recent sophistications in areas of mobile systems and sensor networks demand more and more processing resources. In order to maintain the system autonomy, energy saving is becoming one of the most difficult industrial challenges, in mobile computing. Most of efforts to achieve this goal are focused on improving the embedded systems design and the battery technology, but very few studies target to exploit the input signal time-varying nature. This paper aims to achieve power efficiency by intelligently adapting the processing activity to the input signal local characteristics. It is done by completely rethinking the processing chain, by adopting a non conventional sampling scheme and adaptive rate filtering. The proposed approach, based on the LCSS (Level Crossing Sampling Scheme presents two filtering techniques, able to adapt their sampling rate and filter order by online analyzing the input signal variations. Indeed, the principle is to intelligently exploit the signal local characteristics—which is usually never considered—to filter only the relevant signal parts, by employing the relevant order filters. This idea leads towards a drastic gain in the computational efficiency and hence in the processing power when compared to the classical techniques.

  4. HASE - The Helsinki adaptive sample preparation line

    Energy Technology Data Exchange (ETDEWEB)

    Palonen, V., E-mail: vesa.palonen@helsinki.fi [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 (Finland); Pesonen, A. [Laboratory of Chronology, Finnish Museum of Natural History, P.O. Box 64, FI-00014 (Finland); Herranen, T.; Tikkanen, P. [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 (Finland); Oinonen, M. [Laboratory of Chronology, Finnish Museum of Natural History, P.O. Box 64, FI-00014 (Finland)

    2013-01-15

    We have designed and built an adaptive sample preparation line with separate modules for combustion, molecular sieve handling, CO{sub 2} gas cleaning, CO{sub 2} storage, and graphitization. The line is also connected to an elemental analyzer. Operation of the vacuum equipment, a flow controller, pressure sensors, ovens, and graphitization reactors are automated with a reliable NI-cRIO real-time system. Stepped combustion can be performed in two ovens at temperatures up to 900 Degree-Sign C. Depending on the application, CuO or O{sub 2}-flow combustion can be used. A flow controller is used to adjust the O{sub 2} flow and pressure during combustion. For environmental samples, a module for molecular sieve regeneration and sample desorption is attached to the line replacing the combustion module. In the storage module, CO{sub 2} samples can be stored behind a gas-tight diaphragm valve and either stored for later graphitization or taken for measurements with separate equipment (AMS gas ion source or a separate mass spectrometer). The graphitization module consists of four automated reactors, capable of graphitizing samples with masses from 3 mg down to 50 {mu}g.

  5. Important ingredients for health adaptive information systems.

    Science.gov (United States)

    Senathirajah, Yalini; Bakken, Suzanne

    2011-01-01

    Healthcare information systems frequently do not truly meet clinician needs, due to the complexity, variability, and rapid change in medical contexts. Recently the internet world has been transformed by approaches commonly termed 'Web 2.0'. This paper proposes a Web 2.0 model for a healthcare adaptive architecture. The vision includes creating modular, user-composable systems which aim to make all necessary information from multiple internal and external sources available via a platform, for the user to use, arrange, recombine, author, and share at will, using rich interfaces where advisable. Clinicians can create a set of 'widgets' and 'views' which can transform data, reflect their domain knowledge and cater to their needs, using simple drag and drop interfaces without the intervention of programmers. We have built an example system, MedWISE, embodying the user-facing parts of the model. This approach to HIS is expected to have several advantages, including greater suitability to user needs (reflecting clinician rather than programmer concepts and priorities), incorporation of multiple information sources, agile reconfiguration to meet emerging situations and new treatment deployment, capture of user domain expertise and tacit knowledge, efficiencies due to workflow and human-computer interaction improvements, and greater user acceptance.

  6. A software sampling frequency adaptive algorithm for reducing spectral leakage

    Institute of Scientific and Technical Information of China (English)

    PAN Li-dong; WANG Fei

    2006-01-01

    Spectral leakage caused by synchronous error in a nonsynchronous sampling system is an important cause that reduces the accuracy of spectral analysis and harmonic measurement.This paper presents a software sampling frequency adaptive algorithm that can obtain the actual signal frequency more accurately,and then adjusts sampling interval base on the frequency calculated by software algorithm and modifies sampling frequency adaptively.It can reduce synchronous error and impact of spectral leakage;thereby improving the accuracy of spectral analysis and harmonic measurement for power system signal where frequency changes slowly.This algorithm has high precision just like the simulations show,and it can be a practical method in power system harmonic analysis since it can be implemented easily.

  7. Importance of sampling frequency when collecting diatoms

    KAUST Repository

    Wu, Naicheng

    2016-11-14

    There has been increasing interest in diatom-based bio-assessment but we still lack a comprehensive understanding of how to capture diatoms’ temporal dynamics with an appropriate sampling frequency (ASF). To cover this research gap, we collected and analyzed daily riverine diatom samples over a 1-year period (25 April 2013–30 April 2014) at the outlet of a German lowland river. The samples were classified into five clusters (1–5) by a Kohonen Self-Organizing Map (SOM) method based on similarity between species compositions over time. ASFs were determined to be 25 days at Cluster 2 (June-July 2013) and 13 days at Cluster 5 (February-April 2014), whereas no specific ASFs were found at Cluster 1 (April-May 2013), 3 (August-November 2013) (>30 days) and Cluster 4 (December 2013 - January 2014) (<1 day). ASFs showed dramatic seasonality and were negatively related to hydrological wetness conditions, suggesting that sampling interval should be reduced with increasing catchment wetness. A key implication of our findings for freshwater management is that long-term bio-monitoring protocols should be developed with the knowledge of tracking algal temporal dynamics with an appropriate sampling frequency.

  8. Adaptive sampling for mesh spectrum editing

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiang-jun; ZHANG Hong-xin; BAO Hu-jun

    2006-01-01

    A mesh editing framework is presented in this paper, which integrates Free-Form Deformation (FFD) and geometry signal processing. By using simplified model from original mesh, the editing task can be accomplished with a few operations. We take the deformation of the proxy and the position coordinates of the mesh models as geometry signal. Wavelet analysis is employed to separate local detail information gracefully. The crucial innovation of this paper is a new adaptive regular sampling approach for our signal analysis based editing framework. In our approach, an original mesh is resampled and then refined iteratively which reflects optimization of our proposed spectrum preserving energy. As an extension of our spectrum editing scheme,the editing principle is applied to geometry details transferring, which brings satisfying results.

  9. Importance of sampling frequency when collecting diatoms

    Science.gov (United States)

    Wu, Naicheng; Faber, Claas; Sun, Xiuming; Qu, Yueming; Wang, Chao; Ivetic, Snjezana; Riis, Tenna; Ulrich, Uta; Fohrer, Nicola

    2016-11-01

    There has been increasing interest in diatom-based bio-assessment but we still lack a comprehensive understanding of how to capture diatoms’ temporal dynamics with an appropriate sampling frequency (ASF). To cover this research gap, we collected and analyzed daily riverine diatom samples over a 1-year period (25 April 2013–30 April 2014) at the outlet of a German lowland river. The samples were classified into five clusters (1–5) by a Kohonen Self-Organizing Map (SOM) method based on similarity between species compositions over time. ASFs were determined to be 25 days at Cluster 2 (June-July 2013) and 13 days at Cluster 5 (February-April 2014), whereas no specific ASFs were found at Cluster 1 (April-May 2013), 3 (August-November 2013) (>30 days) and Cluster 4 (December 2013 - January 2014) (management is that long-term bio-monitoring protocols should be developed with the knowledge of tracking algal temporal dynamics with an appropriate sampling frequency.

  10. Importance sampling of severe wind gusts

    NARCIS (Netherlands)

    Bos, R.; Bierbooms, W.A.A.M.; Van Bussel, G.J.W.

    2015-01-01

    An important problem that arises during the design of wind turbines is estimating extreme loads with sufficient accuracy. This is especially difficult during iterative design phases when computational resources are scarce. Over the years, many methods have been proposed to extrapolate extreme load d

  11. Adaptive Sampling Algorithms for Probabilistic Risk Assessment of Nuclear Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Diego Mandelli; Dan Maljovec; Bei Wang; Valerio Pascucci; Peer-Timo Bremer

    2013-09-01

    Nuclear simulations are often computationally expensive, time-consuming, and high-dimensional with respect to the number of input parameters. Thus exploring the space of all possible simulation outcomes is infeasible using finite computing resources. During simulation-based probabilistic risk analysis, it is important to discover the relationship between a potentially large number of input parameters and the output of a simulation using as few simulation trials as possible. This is a typical context for performing adaptive sampling where a few observations are obtained from the simulation, a surrogate model is built to represent the simulation space, and new samples are selected based on the model constructed. The surrogate model is then updated based on the simulation results of the sampled points. In this way, we attempt to gain the most information possible with a small number of carefully selected sampled points, limiting the number of expensive trials needed to understand features of the simulation space. We analyze the specific use case of identifying the limit surface, i.e., the boundaries in the simulation space between system failure and system success. In this study, we explore several techniques for adaptively sampling the parameter space in order to reconstruct the limit surface. We focus on several adaptive sampling schemes. First, we seek to learn a global model of the entire simulation space using prediction models or neighborhood graphs and extract the limit surface as an iso-surface of the global model. Second, we estimate the limit surface by sampling in the neighborhood of the current estimate based on topological segmentations obtained locally. Our techniques draw inspirations from topological structure known as the Morse-Smale complex. We highlight the advantages and disadvantages of using a global prediction model versus local topological view of the simulation space, comparing several different strategies for adaptive sampling in both

  12. On Invertible Sampling and Adaptive Security

    DEFF Research Database (Denmark)

    Ishai, Yuval; Kumarasubramanian, Abishek; Orlandi, Claudio

    2011-01-01

    sampling algorithm A, obtain another sampling algorithm B such that the output of B is computationally indistinguishable from the output of A, but B can be efficiently inverted (even if A cannot). This invertible sampling problem is independently motivated by other cryptographic applications. We show...

  13. Autonomous spatially adaptive sampling in experiments based on curvature, statistical error and sample spacing with applications in LDA measurements

    Science.gov (United States)

    Theunissen, Raf; Kadosh, Jesse S.; Allen, Christian B.

    2015-06-01

    Spatially varying signals are typically sampled by collecting uniformly spaced samples irrespective of the signal content. For signals with inhomogeneous information content, this leads to unnecessarily dense sampling in regions of low interest or insufficient sample density at important features, or both. A new adaptive sampling technique is presented directing sample collection in proportion to local information content, capturing adequately the short-period features while sparsely sampling less dynamic regions. The proposed method incorporates a data-adapted sampling strategy on the basis of signal curvature, sample space-filling, variable experimental uncertainty and iterative improvement. Numerical assessment has indicated a reduction in the number of samples required to achieve a predefined uncertainty level overall while improving local accuracy for important features. The potential of the proposed method has been further demonstrated on the basis of Laser Doppler Anemometry experiments examining the wake behind a NACA0012 airfoil and the boundary layer characterisation of a flat plate.

  14. Adaptive bandwidth measurements of importance functions for speech intelligibility prediction.

    Science.gov (United States)

    Whitmal, Nathaniel A; DeRoy, Kristina

    2011-12-01

    The Articulation Index (AI) and Speech Intelligibility Index (SII) predict intelligibility scores from measurements of speech and hearing parameters. One component in the prediction is the "importance function," a weighting function that characterizes contributions of particular spectral regions of speech to speech intelligibility. Previous work with SII predictions for hearing-impaired subjects suggests that prediction accuracy might improve if importance functions for individual subjects were available. Unfortunately, previous importance function measurements have required extensive intelligibility testing with groups of subjects, using speech processed by various fixed-bandwidth low-pass and high-pass filters. A more efficient approach appropriate to individual subjects is desired. The purpose of this study was to evaluate the feasibility of measuring importance functions for individual subjects with adaptive-bandwidth filters. In two experiments, ten subjects with normal-hearing listened to vowel-consonant-vowel (VCV) nonsense words processed by low-pass and high-pass filters whose bandwidths were varied adaptively to produce specified performance levels in accordance with the transformed up-down rules of Levitt [(1971). J. Acoust. Soc. Am. 49, 467-477]. Local linear psychometric functions were fit to resulting data and used to generate an importance function for VCV words. Results indicate that the adaptive method is reliable and efficient, and produces importance function data consistent with that of the corresponding AI/SII importance function.

  15. 19 CFR 151.67 - Sampling by importer.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Sampling by importer. 151.67 Section 151.67 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... importer. The importer may be permitted after entry to draw samples under Customs supervision in...

  16. Domain Adaptation: Overfitting and Small Sample Statistics

    CERN Document Server

    Foster, Dean; Salakhutdinov, Ruslan

    2011-01-01

    We study the prevalent problem when a test distribution differs from the training distribution. We consider a setting where our training set consists of a small number of sample domains, but where we have many samples in each domain. Our goal is to generalize to a new domain. For example, we may want to learn a similarity function using only certain classes of objects, but we desire that this similarity function be applicable to object classes not present in our training sample (e.g. we might seek to learn that "dogs are similar to dogs" even though images of dogs were absent from our training set). Our theoretical analysis shows that we can select many more features than domains while avoiding overfitting by utilizing data-dependent variance properties. We present a greedy feature selection algorithm based on using T-statistics. Our experiments validate this theory showing that our T-statistic based greedy feature selection is more robust at avoiding overfitting than the classical greedy procedure.

  17. State-dependent importance sampling for a Jackson tandem network

    NARCIS (Netherlands)

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue – it is known that in this setting ‘traditional’ stateindependent importance-sampling distributions perfo

  18. State-dependent importance sampling for a Jackson tandem network

    NARCIS (Netherlands)

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue – it is known that in this setting ‘traditional’ state-independent importance-sampling distributions perf

  19. State-dependent importance sampling for a Jackson tandem network

    NARCIS (Netherlands)

    Miretskiy, Denis; Scheinhardt, Werner; Mandjes, Michel

    2010-01-01

    This article considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue; it is known that in this setting “traditional” state-independent importance-sampling distributions per

  20. State-dependent importance sampling for a Jackson tandem network

    NARCIS (Netherlands)

    D. Miretskiy; W. Scheinhardt; M. Mandjes

    2010-01-01

    This article considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue; it is known that in this setting "traditional" state-independent importance-sampling distributions per

  1. Irregular and adaptive sampling for automatic geophysic measure systems

    Science.gov (United States)

    Avagnina, Davide; Lo Presti, Letizia; Mulassano, Paolo

    2000-07-01

    In this paper a sampling method, based on an irregular and adaptive strategy, is described. It can be used as automatic guide for rovers designed to explore terrestrial and planetary environments. Starting from the hypothesis that a explorative vehicle is equipped with a payload able to acquire measurements of interesting quantities, the method is able to detect objects of interest from measured points and to realize an adaptive sampling, while badly describing the not interesting background.

  2. Time-Stampless Adaptive Nonuniform Sampling for Stochastic Signals

    Science.gov (United States)

    Feizi, Soheil; Goyal, Vivek K.; Medard, Muriel

    2012-10-01

    In this paper, we introduce a time-stampless adaptive nonuniform sampling (TANS) framework, in which time increments between samples are determined by a function of the $m$ most recent increments and sample values. Since only past samples are used in computing time increments, it is not necessary to save sampling times (time stamps) for use in the reconstruction process. We focus on two TANS schemes for discrete-time stochastic signals: a greedy method, and a method based on dynamic programming. We analyze the performances of these schemes by computing (or bounding) their trade-offs between sampling rate and expected reconstruction distortion for autoregressive and Markovian signals. Simulation results support the analysis of the sampling schemes. We show that, by opportunistically adapting to local signal characteristics, TANS may lead to improved power efficiency in some applications.

  3. Time-Stampless Adaptive Nonuniform Sampling for Stochastic Signals

    CERN Document Server

    Feizi, Soheil; Medard, Muriel

    2011-01-01

    In this paper, we introduce a time-stampless adaptive nonuniform sampling (TANS) framework, in which time increments between samples are determined by a function of the $m$ most recent increments and sample values. Since only past samples are used in computing time increments, it is not necessary to save sampling times (time stamps) for use in the reconstruction process. We focus on two TANS schemes for discrete-time stochastic signals: a greedy method, and a method based on dynamic programming. We analyze the performances of these schemes by computing (or bounding) their trade-offs between sampling rate and expected reconstruction distortion for autoregressive and Markovian signals. Simulation results support the analysis of the sampling schemes. We show that, by opportunistically adapting to local signal characteristics, TANS may lead to improved power efficiency in some applications.

  4. Adaptive sampling program support for expedited site characterization

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.

    1993-10-01

    Expedited site characterizations offer substantial savings in time and money when assessing hazardous waste sites. Key to some of these savings is the ability to adapt a sampling program to the ``real-time`` data generated by an expedited site characterization. This paper presents a two-prong approach to supporting adaptive sampling programs: a specialized object-oriented database/geographical information system for data fusion, management and display; and combined Bayesian/geostatistical methods for contamination extent estimation and sample location selection.

  5. Adaptive maximal poisson-disk sampling on surfaces

    KAUST Repository

    Yan, Dongming

    2012-01-01

    In this paper, we study the generation of maximal Poisson-disk sets with varying radii on surfaces. Based on the concepts of power diagram and regular triangulation, we present a geometric analysis of gaps in such disk sets on surfaces, which is the key ingredient of the adaptive maximal Poisson-disk sampling framework. Moreover, we adapt the presented sampling framework for remeshing applications. Several novel and efficient operators are developed for improving the sampling/meshing quality over the state-of-theart. © 2012 ACM.

  6. Identifying important nodes by adaptive LeaderRank

    Science.gov (United States)

    Xu, Shuang; Wang, Pei

    2017-03-01

    Spreading process is a common phenomenon in complex networks. Identifying important nodes in complex networks is of great significance in real-world applications. Based on the spreading process on networks, a lot of measures have been proposed to evaluate the importance of nodes. However, most of the existing measures are appropriate to static networks, which are fragile to topological perturbations. Many real-world complex networks are dynamic rather than static, meaning that the nodes and edges of such networks may change with time, which challenge numerous existing centrality measures. Based on a new weighted mechanism and the newly proposed H-index and LeaderRank (LR), this paper introduces a variant of the LR measure, called adaptive LeaderRank (ALR), which is a new member of the LR-family. Simulations on six real-world networks reveal that the new measure can well balance between prediction accuracy and robustness. More interestingly, the new measure can better adapt to the adjustment or local perturbations of network topologies, as compared with the existing measures. By discussing the detailed properties of the measures from the LR-family, we illustrate that the ALR has its competitive advantages over the other measures. The proposed algorithm enriches the measures to understand complex networks, and may have potential applications in social networks and biological systems.

  7. Adaptive Monte Carlo on multivariate binary sampling spaces

    CERN Document Server

    Schäfer, Christian

    2010-01-01

    A Monte Carlo algorithm is said to be adaptive if it can adjust automatically its current proposal distribution, using past simulations. The choice of the parametric family that defines the set of proposal distributions is critical for a good performance. We treat the problem of constructing such parametric families for adaptive sampling on multivariate binary spaces. A practical motivation for this problem is variable selection in a linear regression context, where we need to either find the best model, with respect to some criterion, or to sample from a Bayesian posterior distribution on the model space. In terms of adaptive algorithms, we focus on the Cross-Entropy (CE) method for optimisation, and the Sequential Monte Carlo (SMC) methods for sampling. Raw versions of both SMC and CE algorithms are easily implemented using binary vectors with independent components. However, for high-dimensional model choice problems, these straightforward proposals do not yields satisfactory results. The key to advanced a...

  8. Adaptive Sampling for High Throughput Data Using Similarity Measures

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sales, A. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-06

    The need for adaptive sampling arises in the context of high throughput data because the rates of data arrival are many orders of magnitude larger than the rates at which they can be analyzed. A very fast decision must therefore be made regarding the value of each incoming observation and its inclusion in the analysis. In this report we discuss one approach to adaptive sampling, based on the new data point’s similarity to the other data points being considered for inclusion. We present preliminary results for one real and one synthetic data set.

  9. Importance Sampling Simulations of Markovian Reliability Systems using Cross Entropy

    NARCIS (Netherlands)

    Ridder, Ad

    2004-01-01

    This paper reports simulation experiments, applying the cross entropy method suchas the importance sampling algorithm for efficient estimation of rare event probabilities in Markovian reliability systems. The method is compared to various failurebiasing schemes that have been proved to give estimato

  10. An importance sampling algorithm for estimating extremes of perpetuity sequences

    DEFF Research Database (Denmark)

    Collamore, Jeffrey F.

    2012-01-01

    In a wide class of problems in insurance and financial mathematics, it is of interest to study the extremal events of a perpetuity sequence. This paper addresses the problem of numerically evaluating these rare event probabilities. Specifically, an importance sampling algorithm is described which...

  11. Adaptation of the methodology of sample surveys for marketing researches

    Directory of Open Access Journals (Sweden)

    Kataev Andrey

    2015-08-01

    Full Text Available The article presents the results of the theory of adaptation of sample survey for the purposes of marketing, that allows to answer the fundamental question of any marketing research – how many objects should be studied for drawing adequate conclusions.

  12. Efficient computation of smoothing splines via adaptive basis sampling

    KAUST Repository

    Ma, Ping

    2015-06-24

    © 2015 Biometrika Trust. Smoothing splines provide flexible nonparametric regression estimators. However, the high computational cost of smoothing splines for large datasets has hindered their wide application. In this article, we develop a new method, named adaptive basis sampling, for efficient computation of smoothing splines in super-large samples. Except for the univariate case where the Reinsch algorithm is applicable, a smoothing spline for a regression problem with sample size n can be expressed as a linear combination of n basis functions and its computational complexity is generally O(n3). We achieve a more scalable computation in the multivariate case by evaluating the smoothing spline using a smaller set of basis functions, obtained by an adaptive sampling scheme that uses values of the response variable. Our asymptotic analysis shows that smoothing splines computed via adaptive basis sampling converge to the true function at the same rate as full basis smoothing splines. Using simulation studies and a large-scale deep earth core-mantle boundary imaging study, we show that the proposed method outperforms a sampling method that does not use the values of response variables.

  13. Stochastic seismic inversion using greedy annealed importance sampling

    Science.gov (United States)

    Xue, Yang; Sen, Mrinal K.

    2016-10-01

    A global optimization method called very fast simulated annealing (VFSA) inversion has been applied to seismic inversion. Here we address some of the limitations of VFSA by developing a new stochastic inference method, named greedy annealed importance sampling (GAIS). GAIS combines VFSA and greedy importance sampling (GIS), which uses a greedy search in the important regions located by VFSA, in order to attain fast convergence and provide unbiased estimation. We demonstrate the performance of GAIS with application to seismic inversion of field post- and pre-stack datasets. The results indicate that GAIS can improve lateral continuity of the inverted impedance profiles and provide better estimation of uncertainties than using VFSA alone. Thus this new hybrid method combining global and local optimization methods can be applied in seismic reservoir characterization and reservoir monitoring for accurate estimation of reservoir models and their uncertainties.

  14. An improved adaptive sampling and experiment design method for aerodynamic optimization

    Institute of Scientific and Technical Information of China (English)

    Huang Jiangtao; Gao Zhenghong; Zhou Zhu; Zhao Ke

    2015-01-01

    Experiment design method is a key to construct a highly reliable surrogate model for numerical optimization in large-scale project. Within the method, the experimental design criterion directly affects the accuracy of the surrogate model and the optimization efficient. According to the shortcomings of the traditional experimental design, an improved adaptive sampling method is pro-posed in this paper. The surrogate model is firstly constructed by basic sparse samples. Then the supplementary sampling position is detected according to the specified criteria, which introduces the energy function and curvature sampling criteria based on radial basis function (RBF) network. Sampling detection criteria considers both the uniformity of sample distribution and the description of hypersurface curvature so as to significantly improve the prediction accuracy of the surrogate model with much less samples. For the surrogate model constructed with sparse samples, the sample uniformity is an important factor to the interpolation accuracy in the initial stage of adaptive sam-pling and surrogate model training. Along with the improvement of uniformity, the curvature description of objective function surface gradually becomes more important. In consideration of these issues, crowdness enhance function and root mean square error (RMSE) feedback function are introduced in C criterion expression. Thus, a new sampling method called RMSE and crowd-ness enhance (RCE) adaptive sampling is established. The validity of RCE adaptive sampling method is studied through typical test function firstly and then the airfoil/wing aerodynamic opti-mization design problem, which has high-dimensional design space. The results show that RCE adaptive sampling method not only reduces the requirement for the number of samples, but also effectively improves the prediction accuracy of the surrogate model, which has a broad prospects for applications.

  15. Adaptation of a Digitally Predistorted RF Amplifier Using Selective Sampling

    Institute of Scientific and Technical Information of China (English)

    R. Neil Braithwaite

    2011-01-01

    In this paper, a reduced-cost method of measuring residual nonlinearities in an adaptive digitally predistorted amplifier is proposed. Measurements obtained by selective sampling of the amplifier output are integrated over the input envelope range to adapt a fourth-order polynomial predistorter with memory correction. Results for a WCDMA input with a 101 carrier configuration show that a transmitter using the proposed method can meet the adjacent channel leakage ratio (ACLR) specification. Inverse modeling of the nonlinearity is proposed as a future extension that will reduce the cost of the system further.

  16. Joint importance sampling of low-order volumetric scattering

    DEFF Research Database (Denmark)

    Georgiev, Iliyan; Křivánek, Jaroslav; Hachisuka, Toshiya

    2013-01-01

    Central to all Monte Carlo-based rendering algorithms is the construction of light transport paths from the light sources to the eye. Existing rendering approaches sample path vertices incrementally when constructing these light transport paths. The resulting probability density is thus a product...... of the conditional densities of each local sampling step, constructed without explicit control over the form of the final joint distribution of the complete path. We analyze why current incremental construction schemes often lead to high variance in the presence of participating media, and reveal...... that such approaches are an unnecessary legacy inherited from traditional surface-based rendering algorithms. We devise joint importance sampling of path vertices in participating media to construct paths that explicitly account for the product of all scattering and geometry terms along a sequence of vertices instead...

  17. Importance of accurate sampling techniques in microbiological diagnosis of endophthalmitis

    OpenAIRE

    Banu A.; Sriprakash KS; Nagaraj ER; Meundi M

    2011-01-01

    BackgroundEndophthalmitis is an ocular emergency and bacteria arethe commonest aetiological agents of infectiousendophthalmitis. Any delay in treatment will result inserious complications like complete loss of vision.Therefore, obtaining the most appropriate sample is ofparamount importance for a microbiologist to identify theaetiological agents that help the ophthalmologist inplanning treatment.ObjectiveThis study was undertaken to determine the intraocularspecimen that is most likely to yie...

  18. Importance of accurate sampling techniques in microbiological diagnosis of endophthalmitis

    Directory of Open Access Journals (Sweden)

    Banu A

    2011-05-01

    Full Text Available BackgroundEndophthalmitis is an ocular emergency and bacteria arethe commonest aetiological agents of infectiousendophthalmitis. Any delay in treatment will result inserious complications like complete loss of vision.Therefore, obtaining the most appropriate sample is ofparamount importance for a microbiologist to identify theaetiological agents that help the ophthalmologist inplanning treatment.ObjectiveThis study was undertaken to determine the intraocularspecimen that is most likely to yield a positive culture onmicrobiological examination.MethodsFrom 60 cases, intraocular samples were collected in theoperation theatre under anaesthesia. The samples obtainedwere aqueous humour and vitreous humour by vitreous tap,vitreous biopsy or pars plana vitrectomy. The specimenswere processed within half an hour, first by inoculating ontoculture media and then direct smear examination by Gram’sStainResultsEighty samples were obtained from 60 cases of which themost were vitreous fluid (vitreous biopsy/tap + vitrectomyfluid, i.e., 75%. Culture was positive in 88% vitrectomy fluidas compared to 74% in vitreous tap/biopsy followed by 20%in aqueous fluid.ConclusionsVitrectomy fluid appears to be the best sample for culturefrom clinically diagnosed endophthalmitis cases.

  19. Variance Analysis and Adaptive Sampling for Indirect Light Path Reuse

    Institute of Scientific and Technical Information of China (English)

    Hao Qin; Xin Sun; Jun Yan; Qi-Ming Hou; Zhong Ren; Kun Zhou

    2016-01-01

    In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes — in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the covariance of the reconstruction samples dominates the estimation variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the covariance. We also find that the covariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the covariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost.

  20. A cheap and quickly adaptable in situ electrical contacting TEM sample holder design.

    Science.gov (United States)

    Börrnert, Felix; Voigtländer, Ralf; Rellinghaus, Bernd; Büchner, Bernd; Rümmeli, Mark H; Lichte, Hannes

    2014-04-01

    In situ electrical characterization of nanostructures inside a transmission electron microscope provides crucial insight into the mechanisms of functioning micro- and nano-electronic devices. For such in situ investigations specialized sample holders are necessary. A simple and affordable but flexible design is important, especially, when sample geometries change, a holder should be adaptable with minimum effort. Atomic resolution imaging is standard nowadays, so a sample holder must ensure this capability. A sample holder design for on-chip samples is presented that fulfils these requisites. On-chip sample devices have the advantage that they can be manufactured via standard fabrication routes.

  1. Importance sampling for failure probabilities in computing and data transmission

    DEFF Research Database (Denmark)

    Asmussen, Søren

    2009-01-01

    In this paper we study efficient simulation algorithms for estimating P(X›x), where X is the total time of a job with ideal time $T$ that needs to be restarted after a failure. The main tool is importance sampling, where a good importance distribution is identified via an asymptotic description...... of the conditional distribution of T given X›x. If T≡t is constant, the problem reduces to the efficient simulation of geometric sums, and a standard algorithm involving a Cramér-type root, γ(t), is available. However, we also discuss an algorithm that avoids finding the root. If T is random, particular attention...... is given to T having either a gamma-like tail or a regularly varying tail, and to failures at Poisson times. Different types of conditional limit occur, in particular exponentially tilted Gumbel distributions and Pareto distributions. The algorithms based upon importance distributions for T using...

  2. Semigroups and sequential importance sampling for multiway tables

    CERN Document Server

    Yoshida, Ruriko; Wei, Shaoceng; Zhou, Feng; Haws, David

    2011-01-01

    When an interval of integers between the lower bound $l_i$ and the upper bound $u_i$ is the support of the marginal distribution $n_i|(n_{i-1}, ...,n_1)$, Chen et al, 2005 noticed that sampling from the interval at each step, for $n_i$ during a sequential importance sampling (SIS) procedure, always produces a table which satisfies the marginal constraints. However, in general, the interval may not be equal to the support of the marginal distribution. In this case, the SIS procedure may produce tables which do not satisfy the marginal constraints, leading to rejection Chen et al 2006. In this paper we consider the uniform distribution as the target distribution. First we show that if we fix the number of rows and columns of the design matrix of the model for contingency tables then there exists a polynomial time algorithm in terms of the input size to sample a table from the set of all tables satisfying all marginals defined by the given model via the SIS procedure without rejection. We then show experimentall...

  3. Distributed Database Kriging for Adaptive Sampling (D2 KAS)

    Science.gov (United States)

    Roehm, Dominic; Pavel, Robert S.; Barros, Kipton; Rouet-Leduc, Bertrand; McPherson, Allen L.; Germann, Timothy C.; Junghans, Christoph

    2015-07-01

    We present an adaptive sampling method supplemented by a distributed database and a prediction method for multiscale simulations using the Heterogeneous Multiscale Method. A finite-volume scheme integrates the macro-scale conservation laws for elastodynamics, which are closed by momentum and energy fluxes evaluated at the micro-scale. In the original approach, molecular dynamics (MD) simulations are launched for every macro-scale volume element. Our adaptive sampling scheme replaces a large fraction of costly micro-scale MD simulations with fast table lookup and prediction. The cloud database Redis provides the plain table lookup, and with locality aware hashing we gather input data for our prediction scheme. For the latter we use kriging, which estimates an unknown value and its uncertainty (error) at a specific location in parameter space by using weighted averages of the neighboring points. We find that our adaptive scheme significantly improves simulation performance by a factor of 2.5-25, while retaining high accuracy for various choices of the algorithm parameters.

  4. The Importance of Formalizing Computational Models of Face Adaptation Aftereffects

    Science.gov (United States)

    Ross, David A.; Palmeri, Thomas J.

    2016-01-01

    Face adaptation is widely used as a means to probe the neural representations that support face recognition. While the theories that relate face adaptation to behavioral aftereffects may seem conceptually simple, our work has shown that testing computational instantiations of these theories can lead to unexpected results. Instantiating a model of face adaptation not only requires specifying how faces are represented and how adaptation shapes those representations but also specifying how decisions are made, translating hidden representational states into observed responses. Considering the high-dimensionality of face representations, the parallel activation of multiple representations, and the non-linearity of activation functions and decision mechanisms, intuitions alone are unlikely to succeed. If the goal is to understand mechanism, not simply to examine the boundaries of a behavioral phenomenon or correlate behavior with brain activity, then formal computational modeling must be a component of theory testing. To illustrate, we highlight our recent computational modeling of face adaptation aftereffects and discuss how models can be used to understand the mechanisms by which faces are recognized. PMID:27378960

  5. Improving Wang-Landau sampling with adaptive windows.

    Science.gov (United States)

    Cunha-Netto, A G; Caparica, A A; Tsai, Shan-Ho; Dickman, Ronald; Landau, D P

    2008-11-01

    Wang-Landau sampling (WLS) of large systems requires dividing the energy range into "windows" and joining the results of simulations in each window. The resulting density of states (and associated thermodynamic functions) is shown to suffer from boundary effects in simulations of lattice polymers and the five-state Potts model. Here, we implement WLS using adaptive windows. Instead of defining fixed energy windows (or windows in the energy-magnetization plane for the Potts model), the boundary positions depend on the set of energy values on which the histogram is flat at a given stage of the simulation. Shifting the windows each time the modification factor f is reduced, we eliminate border effects that arise in simulations using fixed windows. Adaptive windows extend significantly the range of system sizes that may be studied reliably using WLS.

  6. Improving Wang-Landau sampling with adaptive windows

    Science.gov (United States)

    Cunha-Netto, A. G.; Caparica, A. A.; Tsai, Shan-Ho; Dickman, Ronald; Landau, D. P.

    2008-11-01

    Wang-Landau sampling (WLS) of large systems requires dividing the energy range into “windows” and joining the results of simulations in each window. The resulting density of states (and associated thermodynamic functions) is shown to suffer from boundary effects in simulations of lattice polymers and the five-state Potts model. Here, we implement WLS using adaptive windows. Instead of defining fixed energy windows (or windows in the energy-magnetization plane for the Potts model), the boundary positions depend on the set of energy values on which the histogram is flat at a given stage of the simulation. Shifting the windows each time the modification factor f is reduced, we eliminate border effects that arise in simulations using fixed windows. Adaptive windows extend significantly the range of system sizes that may be studied reliably using WLS.

  7. Importance Sampling for Failure Probabilities in Computing and Data Transmission

    DEFF Research Database (Denmark)

    Asmussen, Søren

    We study efficient simulation algorithms for estimating P(Χ > χ), where Χ is the total time of a job with ideal time T that needs to be restarted after a failure. The main tool is importance sampling where one tries to identify a good importance distribution via an asymptotic description...... of the conditional distribution of T given Χ > χ. If T ≡ t is constant, the problem reduces to the efficient simulation of geometric sums, and a standard algorithm involving a Cramér type root  γ(t) is available. However, we also discuss  an algorithm avoiding the rootfinding. If T is random, particular attention...... is given to T having either a gamma-like tail or a regularly varying tail, and to failures at Poisson times. Different type of conditional limits occur, in particular exponentially tilted Gumbel distributions and Pareto distributions. The algorithms based upon importance distributions for T using...

  8. Stochastic approximation Monte Carlo importance sampling for approximating exact conditional probabilities

    KAUST Repository

    Cheon, Sooyoung

    2013-02-16

    Importance sampling and Markov chain Monte Carlo methods have been used in exact inference for contingency tables for a long time, however, their performances are not always very satisfactory. In this paper, we propose a stochastic approximation Monte Carlo importance sampling (SAMCIS) method for tackling this problem. SAMCIS is a combination of adaptive Markov chain Monte Carlo and importance sampling, which employs the stochastic approximation Monte Carlo algorithm (Liang et al., J. Am. Stat. Assoc., 102(477):305-320, 2007) to draw samples from an enlarged reference set with a known Markov basis. Compared to the existing importance sampling and Markov chain Monte Carlo methods, SAMCIS has a few advantages, such as fast convergence, ergodicity, and the ability to achieve a desired proportion of valid tables. The numerical results indicate that SAMCIS can outperform the existing importance sampling and Markov chain Monte Carlo methods: It can produce much more accurate estimates in much shorter CPU time than the existing methods, especially for the tables with high degrees of freedom. © 2013 Springer Science+Business Media New York.

  9. Importance sampling. I. Computing multimodel p values in linkage analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kong, A.; Frigge, M.; Irwin, M.; Cox, N. (Univ. of Chicago, IL (United States))

    1992-12-01

    In linkage analysis, when the lod score is maximized over multiple genetic models, standard asymptotic approximation of the significance level does not apply. Monte Carlo methods can be used to estimate the p value, but procedures currently used are extremely inefficient. The authors propose a Monte Carlo procedure based on the concept of importance sampling, which can be thousands of times more efficient than current procedures. With a reasonable amount of computing time, extremely accurate estimates of the p values can be obtained. Both theoretical results and an example of maturity-onset diabetes of the young (MODY) are presented to illustrate the efficiency performance of their method. Relations between single-model and multimodel p values are explored. The new procedure is also used to investigate the performance of asymptotic approximations in a single model situation. 22 refs., 6 figs., 1 tab.

  10. Adaptation pathways of global wheat production: Importance of strategic adaptation to climate change.

    Science.gov (United States)

    Tanaka, Akemi; Takahashi, Kiyoshi; Masutomi, Yuji; Hanasaki, Naota; Hijioka, Yasuaki; Shiogama, Hideo; Yamanaka, Yasuhiro

    2015-09-16

    Agricultural adaptation is necessary to reduce the negative impacts of climate change on crop yields and to maintain food production. However, few studies have assessed the course of adaptation along with the progress of climate change in each of the current major food producing countries. Adaptation pathways, which describe the temporal sequences of adaptations, are helpful for illustrating the timing and intensity of the adaptation required. Here we present adaptation pathways in the current major wheat-producing countries, based on sequential introduction of the minimum adaptation measures necessary to maintain current wheat yields through the 21st century. We considered two adaptation options: (i) expanding irrigation infrastructure; and (ii) switching crop varieties and developing new heat-tolerant varieties. We find that the adaptation pathways differ markedly among the countries. The adaptation pathways are sensitive to both the climate model uncertainty and natural variability of the climate system, and the degree of sensitivity differs among countries. Finally, the negative impacts of climate change could be moderated by implementing adaptations steadily according to forecasts of the necessary future adaptations, as compared to missing the appropriate timing to implement adaptations.

  11. Semigroups and sequential importance sampling for multiway tables and beyond

    CERN Document Server

    Xi, Jing; Zhou, Feng; Yoshida, Ruriko; Haws, David

    2011-01-01

    When an interval of integers between the lower bound l_i and the upper bounds u_i is the support of the marginal distribution n_i|(n_{i-1}, ...,n_1), Chen et al. 2005 noticed that sampling from the interval at each step, for n_i during the sequential importance sampling (SIS) procedure, always produces a table which satisfies the marginal constraints. However, in general, the interval may not be equal to the support of the marginal distribution. In this case, the SIS procedure may produce tables which do not satisfy the marginal constraints, leading to rejection [Chen et al. 2006]. Rejecting tables is computationally expensive and incorrect proposal distributions result in biased estimators for the number of tables given its marginal sums. This paper has two focuses; (1) we propose a correction coefficient which corrects an interval of integers between the lower bound l_i and the upper bounds u_i to the support of the marginal distribution asymptotically even with rejections and with the same time complexity ...

  12. Gap processing for adaptive maximal Poisson-disk sampling

    KAUST Repository

    Yan, Dongming

    2013-09-01

    In this article, we study the generation of maximal Poisson-disk sets with varying radii. First, we present a geometric analysis of gaps in such disk sets. This analysis is the basis for maximal and adaptive sampling in Euclidean space and on manifolds. Second, we propose efficient algorithms and data structures to detect gaps and update gaps when disks are inserted, deleted, moved, or when their radii are changed.We build on the concepts of regular triangulations and the power diagram. Third, we show how our analysis contributes to the state-of-the-art in surface remeshing. © 2013 ACM.

  13. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    Science.gov (United States)

    Grace, J. M.; Verseux, C.; Gentry, D.; Moffet, A.; Thayabaran, R.; Wong, N.; Rothschild, L.

    2013-12-01

    The adaptation of micro-organisms to their environments is a complex process of interaction between the pressures of the environment and of competition. Reducing this multifactorial process to environmental exposure in the laboratory is a common tool for elucidating individual mechanisms of evolution, such as mutation rates[Wielgoss et al., 2013]. Although such studies inform fundamental questions about the way adaptation and even speciation occur, they are often limited by labor-intensive manual techniques[Wassmann et al., 2010]. Current methods for controlled study of microbial adaptation limit the length of time, the depth of collected data, and the breadth of applied environmental conditions. Small idiosyncrasies in manual techniques can have large effects on outcomes; for example, there are significant variations in induced radiation resistances following similar repeated exposure protocols[Alcántara-Díaz et al., 2004; Goldman and Travisano, 2011]. We describe here a project under development to allow rapid cycling of multiple types of microbial environmental exposure. The system allows continuous autonomous monitoring and data collection of both single species and sampled communities, independently and concurrently providing multiple types of controlled environmental pressure (temperature, radiation, chemical presence or absence, and so on) to a microbial community in dynamic response to the ecosystem's current status. When combined with DNA sequencing and extraction, such a controlled environment can cast light on microbial functional development, population dynamics, inter- and intra-species competition, and microbe-environment interaction. The project's goal is to allow rapid, repeatable iteration of studies of both natural and artificial microbial adaptation. As an example, the same system can be used both to increase the pH of a wet soil aliquot over time while periodically sampling it for genetic activity analysis, or to repeatedly expose a culture of

  14. Adaptive Sampling-Based Information Collection for Wireless Body Area Networks.

    Science.gov (United States)

    Xu, Xiaobin; Zhao, Fang; Wang, Wendong; Tian, Hui

    2016-08-31

    To collect important health information, WBAN applications typically sense data at a high frequency. However, limited by the quality of wireless link, the uploading of sensed data has an upper frequency. To reduce upload frequency, most of the existing WBAN data collection approaches collect data with a tolerable error. These approaches can guarantee precision of the collected data, but they are not able to ensure that the upload frequency is within the upper frequency. Some traditional sampling based approaches can control upload frequency directly, however, they usually have a high loss of information. Since the core task of WBAN applications is to collect health information, this paper aims to collect optimized information under the limitation of upload frequency. The importance of sensed data is defined according to information theory for the first time. Information-aware adaptive sampling is proposed to collect uniformly distributed data. Then we propose Adaptive Sampling-based Information Collection (ASIC) which consists of two algorithms. An adaptive sampling probability algorithm is proposed to compute sampling probabilities of different sensed values. A multiple uniform sampling algorithm provides uniform samplings for values in different intervals. Experiments based on a real dataset show that the proposed approach has higher performance in terms of data coverage and information quantity. The parameter analysis shows the optimized parameter settings and the discussion shows the underlying reason of high performance in the proposed approach.

  15. Peptide Backbone Sampling Convergence with the Adaptive Biasing Force Algorithm

    Science.gov (United States)

    Faller, Christina E.; Reilly, Kyle A.; Hills, Ronald D.; Guvench, Olgun

    2013-01-01

    Complete Boltzmann sampling of reaction coordinates in biomolecular systems continues to be a challenge for unbiased molecular dynamics simulations. A growing number of methods have been developed for applying biases to biomolecular systems to enhance sampling while enabling recovery of the unbiased (Boltzmann) distribution of states. The Adaptive Biasing Force (ABF) algorithm is one such method, and works by canceling out the average force along the desired reaction coordinate(s) using an estimate of this force progressively accumulated during the simulation. Upon completion of the simulation, the potential of mean force, and therefore Boltzmann distribution of states, is obtained by integrating this average force. In an effort to characterize the expected performance in applications such as protein loop sampling, ABF was applied to the full ranges of the Ramachandran ϕ/ψ backbone dihedral reaction coordinates for dipeptides of the 20 amino acids using all-atom explicit-water molecular dynamics simulations. Approximately half of the dipeptides exhibited robust and rapid convergence of the potential of mean force as a function of ϕ/ψ in triplicate 50-ns simulations, while the remainder exhibited varying degrees of less complete convergence. The greatest difficulties in achieving converged ABF sampling were seen in the branched-sidechain amino acids threonine and valine, as well as the special case of proline. Proline dipeptide sampling was further complicated by trans-to-cis peptide bond isomerization not observed in unbiased control molecular dynamics simulations. Overall, the ABF method was found to be a robust means of sampling the entire ϕ/ψ reaction coordinate for the 20 amino acids, including high free-energy regions typically inaccessible in standard molecular dynamics simulations. PMID:23215032

  16. Adaptive sampling for nonlinear dimensionality reduction based on manifold learning

    DEFF Research Database (Denmark)

    Franz, Thomas; Zimmermann, Ralf; Goertz, Stefan

    2017-01-01

    We make use of the non-intrusive dimensionality reduction method Isomap in order to emulate nonlinear parametric flow problems that are governed by the Reynolds-averaged Navier-Stokes equations. Isomap is a manifold learning approach that provides a low-dimensional embedding space...... that is approximately isometric to the manifold that is assumed to be formed by the high-fidelity Navier-Stokes flow solutions under smooth variations of the inflow conditions. The focus of the work at hand is the adaptive construction and refinement of the Isomap emulator: We exploit the non-Euclidean Isomap metric...... to detect and fill up gaps in the sampling in the embedding space. The performance of the proposed manifold filling method will be illustrated by numerical experiments, where we consider nonlinear parameter-dependent steady-state Navier-Stokes flows in the transonic regime....

  17. Multi-Scaling Sampling: An Adaptive Sampling Method for Discovering Approximate Association Rules

    Institute of Scientific and Technical Information of China (English)

    Cai-Yan Jia; Xie-Ping Gao

    2005-01-01

    One of the obstacles of the efficient association rule mining is the explosive expansion of data sets since it is costly or impossible to scan large databases, esp., for multiple times. A popular solution to improve the speed and scalability of the association rule mining is to do the algorithm on a random sample instead of the entire database. But how to effectively define and efficiently estimate the degree of error with respect to the outcome of the algorithm, and how to determine the sample size needed are entangling researches until now. In this paper, an effective and efficient algorithm is given based on the PAC (Probably Approximate Correct) learning theory to measure and estimate sample error. Then, a new adaptive, on-line, fast sampling strategy - multi-scaling sampling - is presented inspired by MRA (Multi-Resolution Analysis) and Shannon sampling theorem, for quickly obtaining acceptably approximate association rules at appropriate sample size. Both theoretical analysis and empirical study have showed that the sampling strategy can achieve a very good speed-accuracy trade-off.

  18. Temporally adaptive sampling: a case study in rare species survey design with marbled salamanders (Ambystoma opacum.

    Directory of Open Access Journals (Sweden)

    Noah D Charney

    Full Text Available Improving detection rates for elusive species with clumped distributions is often accomplished through adaptive sampling designs. This approach can be extended to include species with temporally variable detection probabilities. By concentrating survey effort in years when the focal species are most abundant or visible, overall detection rates can be improved. This requires either long-term monitoring at a few locations where the species are known to occur or models capable of predicting population trends using climatic and demographic data. For marbled salamanders (Ambystoma opacum in Massachusetts, we demonstrate that annual variation in detection probability of larvae is regionally correlated. In our data, the difference in survey success between years was far more important than the difference among the three survey methods we employed: diurnal surveys, nocturnal surveys, and dipnet surveys. Based on these data, we simulate future surveys to locate unknown populations under a temporally adaptive sampling framework. In the simulations, when pond dynamics are correlated over the focal region, the temporally adaptive design improved mean survey success by as much as 26% over a non-adaptive sampling design. Employing a temporally adaptive strategy costs very little, is simple, and has the potential to substantially improve the efficient use of scarce conservation funds.

  19. The importance of cooling of urine samples for doping analysis

    NARCIS (Netherlands)

    Kuenen, J. Gijs; Konings, Wil N.

    2010-01-01

    Storing and transporting of urine samples for doping analysis, as performed by the anti-doping organizations associated with the World Anti-Doping Agency, does not include a specific protocol for cooled transport from the place of urine sampling to the doping laboratory, although low cost cooling fa

  20. The importance of cooling of urine samples for doping analysis

    NARCIS (Netherlands)

    Kuenen, J.G.; Konings, W.N.

    2009-01-01

    Storing and transporting of urine samples for doping analysis, as performed by the anti-doping organizations associated with the World Anti-Doping Agency, does not include a specific protocol for cooled transport from the place of urine sampling to the doping laboratory, although low cost cooling fa

  1. Monte Carlo importance sampling for the MCNP{trademark} general source

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenstein, H.

    1996-01-09

    Research was performed to develop an importance sampling procedure for a radiation source. The procedure was developed for the MCNP radiation transport code, but the approach itself is general and can be adapted to other Monte Carlo codes. The procedure, as adapted to MCNP, relies entirely on existing MCNP capabilities. It has been tested for very complex descriptions of a general source, in the context of the design of spent-reactor-fuel storage casks. Dramatic improvements in calculation efficiency have been observed in some test cases. In addition, the procedure has been found to provide an acceleration to acceptable convergence, as well as the benefit of quickly identifying user specified variance-reduction in the transport that effects unstable convergence.

  2. Importance of eccentric actions in performance adaptations to resistance training

    Science.gov (United States)

    Dudley, Gary A.; Miller, Bruce J.; Buchanan, Paul; Tesch, Per A.

    1991-01-01

    The importance of eccentric (ecc) muscle actions in resistance training for the maintenance of muscle strength and mass in hypogravity was investigated in experiments in which human subjects, divided into three groups, were asked to perform four-five sets of 6 to 12 repetitions (rep) per set of three leg press and leg extension exercises, 2 days each weeks for 19 weeks. One group, labeled 'con', performed each rep with only concentric (con) actions, while group con/ecc with performed each rep with only ecc actions; the third group, con/con, performed twice as many sets with only con actions. Control subjects did not train. It was found that resistance training wih both con and ecc actions induced greater increases in muscle strength than did training with only con actions.

  3. Parallel importance sampling in conditional linear Gaussian networks

    DEFF Research Database (Denmark)

    Salmerón, Antonio; Ramos-López, Darío; Borchani, Hanen

    2015-01-01

    In this paper we analyse the problem of probabilistic inference in CLG networks when evidence comes in streams. In such situations, fast and scalable algorithms, able to provide accurate responses in a short time are required. We consider the instantiation of variational inference and importance ...

  4. Importance Nested Sampling and the MultiNest Algorithm

    CERN Document Server

    Feroz, F; Cameron, E; Pettitt, A N

    2013-01-01

    Bayesian inference involves two main computational challenges. First, in estimating the parameters of some model for the data, the posterior distribution may well be highly multi-modal: a regime in which the convergence to stationarity of traditional Markov Chain Monte Carlo (MCMC) techniques becomes incredibly slow. Second, in selecting between a set of competing models the necessary estimation of the Bayesian evidence for each is, by definition, a (possibly high-dimensional) integration over the entire parameter space; again this can be a daunting computational task, although new Monte Carlo (MC) integration algorithms offer solutions of ever increasing efficiency. Nested sampling (NS) is one such contemporary MC strategy targeted at calculation of the Bayesian evidence, but which also enables posterior inference as a by-product, thereby allowing simultaneous parameter estimation and model selection. The widely-used MultiNest algorithm presents a particularly efficient implementation of the NS technique for...

  5. Job performance ratings : The relative importance of mental ability, conscientiousness, and career adaptability

    NARCIS (Netherlands)

    Ohme, Melanie; Zacher, Hannes

    2015-01-01

    According to career construction theory, continuous adaptation to the work environment is crucial to achieve work and career success. In this study, we examined the relative importance of career adaptability for job performance ratings using an experimental policy-capturing design. Employees (N = 13

  6. State-independent importance sampling for random walks with regularly varying increments

    Directory of Open Access Journals (Sweden)

    Karthyek R. A. Murthy

    2015-03-01

    Full Text Available We develop importance sampling based efficient simulation techniques for three commonly encountered rare event probabilities associated with random walks having i.i.d. regularly varying increments; namely, 1 the large deviation probabilities, 2 the level crossing probabilities, and 3 the level crossing probabilities within a regenerative cycle. Exponential twisting based state-independent methods, which are effective in efficiently estimating these probabilities for light-tailed increments are not applicable when the increments are heavy-tailed. To address the latter case, more complex and elegant state-dependent efficient simulation algorithms have been developed in the literature over the last few years. We propose that by suitably decomposing these rare event probabilities into a dominant and further residual components, simpler state-independent importance sampling algorithms can be devised for each component resulting in composite unbiased estimators with desirable efficiency properties. When the increments have infinite variance, there is an added complexity in estimating the level crossing probabilities as even the well known zero-variance measures have an infinite expected termination time. We adapt our algorithms so that this expectation is finite while the estimators remain strongly efficient. Numerically, the proposed estimators perform at least as well, and sometimes substantially better than the existing state-dependent estimators in the literature.

  7. Sampling plant diversity and rarity at landscape scales: importance of sampling time in species detectability.

    Directory of Open Access Journals (Sweden)

    Jian Zhang

    Full Text Available Documenting and estimating species richness at regional or landscape scales has been a major emphasis for conservation efforts, as well as for the development and testing of evolutionary and ecological theory. Rarely, however, are sampling efforts assessed on how they affect detection and estimates of species richness and rarity. In this study, vascular plant richness was sampled in 356 quarter hectare time-unlimited survey plots in the boreal region of northeast Alberta. These surveys consisted of 15,856 observations of 499 vascular plant species (97 considered to be regionally rare collected by 12 observers over a 2 year period. Average survey time for each quarter-hectare plot was 82 minutes, ranging from 20 to 194 minutes, with a positive relationship between total survey time and total plant richness. When survey time was limited to a 20-minute search, as in other Alberta biodiversity methods, 61 species were missed. Extending the survey time to 60 minutes, reduced the number of missed species to 20, while a 90-minute cut-off time resulted in the loss of 8 species. When surveys were separated by habitat type, 60 minutes of search effort sampled nearly 90% of total observed richness for all habitats. Relative to rare species, time-unlimited surveys had ∼ 65% higher rare plant detections post-20 minutes than during the first 20 minutes of the survey. Although exhaustive sampling was attempted, observer bias was noted among observers when a subsample of plots was re-surveyed by different observers. Our findings suggest that sampling time, combined with sample size and observer effects, should be considered in landscape-scale plant biodiversity surveys.

  8. Robust Fusion of Irregularly Sampled Data Using Adaptive Normalized Convolution

    NARCIS (Netherlands)

    Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

    2006-01-01

    We present a novel algorithm for image fusion from irregularly sampled data. The method is based on the framework of normalized convolution (NC), in which the local signal is approximated through a projection onto a subspace. The use of polynomial basis functions in this paper makes NC equivalent to

  9. Climate variables explain neutral and adaptive variation within salmonid metapopulations: the importance of replication in landscape genetics.

    Science.gov (United States)

    Hand, Brian K; Muhlfeld, Clint C; Wade, Alisa A; Kovach, Ryan P; Whited, Diane C; Narum, Shawn R; Matala, Andrew P; Ackerman, Michael W; Garner, Brittany A; Kimball, John S; Stanford, Jack A; Luikart, Gordon

    2016-02-01

    Understanding how environmental variation influences population genetic structure is important for conservation management because it can reveal how human stressors influence population connectivity, genetic diversity and persistence. We used riverscape genetics modelling to assess whether climatic and habitat variables were related to neutral and adaptive patterns of genetic differentiation (population-specific and pairwise FST ) within five metapopulations (79 populations, 4583 individuals) of steelhead trout (Oncorhynchus mykiss) in the Columbia River Basin, USA. Using 151 putatively neutral and 29 candidate adaptive SNP loci, we found that climate-related variables (winter precipitation, summer maximum temperature, winter highest 5% flow events and summer mean flow) best explained neutral and adaptive patterns of genetic differentiation within metapopulations, suggesting that climatic variation likely influences both demography (neutral variation) and local adaptation (adaptive variation). However, we did not observe consistent relationships between climate variables and FST across all metapopulations, underscoring the need for replication when extrapolating results from one scale to another (e.g. basin-wide to the metapopulation scale). Sensitivity analysis (leave-one-population-out) revealed consistent relationships between climate variables and FST within three metapopulations; however, these patterns were not consistent in two metapopulations likely due to small sample sizes (N = 10). These results provide correlative evidence that climatic variation has shaped the genetic structure of steelhead populations and highlight the need for replication and sensitivity analyses in land and riverscape genetics.

  10. Adaptive Sampling for WSAN Control Applications Using Artificial Neural Networks

    OpenAIRE

    2012-01-01

    Wireless sensor actuator networks are becoming a solution for control applications. Reliable data transmission and real time constraints are the most significant challenges. Control applications will have some Quality of Service (QoS) requirements from the sensor network, such as minimum delay and guaranteed delivery of packets. We investigate variable sampling method to mitigate the effects of time delays in wireless networked control systems using an observer based control system model. Our...

  11. Adapting sampling plans to caribou distribution on calving grounds

    Directory of Open Access Journals (Sweden)

    Michel Crête

    1991-10-01

    Full Text Available Between 1984 and 1988, the size of the two caribou herds in northern Québec was derived by combining estimates of female numbers on calving grounds in June and composition counts during rut in autumn. Sampling with aerial photos was conducted on calving grounds to determine the number of animals per km2, telemetry served to estimate the proportion of females in the census area at the time of photography in addition to summer survival rate, and helicopter or ground observations were used for composition counts. Observers were able to detect on black and white negatives over 95 percent of caribou counted from a helicopter flying at low altitude over the same area; photo scale varied between = 1:3 600 and 1:6 000. Sampling units covering less than 15-20 ha were the best for sampling caribou distribution on calving grounds, where density generally averaged » 10 individuals-km"2. Around 90 percent of caribou on calving grounds were females; others were mostly yearling males. During the 1-2 day photographic census, 64 to 77 percent of the females were present on the calving areas. Summer survival exceeded 95 percent in three summers. In autumn, females composed between 45 and 54 percent of each herd. The Rivière George herd was estimated at 682 000 individuals (± 36%; alpha = 0.10 in 1988. This estimate was imprecise due to insufficiens sample size for measuring animal density on the calving ground and for determining proportion of females on the calving ground at the time of the photo census. To improve precision and reduce cost, it is proposed to estimate herd size of tundra caribou in one step, using only aerial photos in early June without telemetry.

  12. Long-term dynamics of adaptive evolution in a globally important phytoplankton species to ocean acidification

    Science.gov (United States)

    Schlüter, Lothar; Lohbeck, Kai T.; Gröger, Joachim P.; Riebesell, Ulf; Reusch, Thorsten B. H.

    2016-01-01

    Marine phytoplankton may adapt to ocean change, such as acidification or warming, because of their large population sizes and short generation times. Long-term adaptation to novel environments is a dynamic process, and phenotypic change can take place thousands of generations after exposure to novel conditions. We conducted a long-term evolution experiment (4 years = 2100 generations), starting with a single clone of the abundant and widespread coccolithophore Emiliania huxleyi exposed to three different CO2 levels simulating ocean acidification (OA). Growth rates as a proxy for Darwinian fitness increased only moderately under both levels of OA [+3.4% and +4.8%, respectively, at 1100 and 2200 μatm partial pressure of CO2 (Pco2)] relative to control treatments (ambient CO2, 400 μatm). Long-term adaptation to OA was complex, and initial phenotypic responses of ecologically important traits were later reverted. The biogeochemically important trait of calcification, in particular, that had initially been restored within the first year of evolution was later reduced to levels lower than the performance of nonadapted populations under OA. Calcification was not constitutively lost but returned to control treatment levels when high CO2–adapted isolates were transferred back to present-day control CO2 conditions. Selection under elevated CO2 exacerbated a general decrease of cell sizes under long-term laboratory evolution. Our results show that phytoplankton may evolve complex phenotypic plasticity that can affect biogeochemically important traits, such as calcification. Adaptive evolution may play out over longer time scales (>1 year) in an unforeseen way under future ocean conditions that cannot be predicted from initial adaptation responses. PMID:27419227

  13. Simulation of a Jackson tandem network using state-dependent importance sampling

    NARCIS (Netherlands)

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rareevent simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jackson twonode tandem queue. It is known that in this setting ‘traditional’ state-independent importance-sampling distributions perform po

  14. Simulation of a Jackson tandem network using state-dependent importance sampling

    NARCIS (Netherlands)

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jackson two-node tandem queue. It is known that in this setting `traditional' state-independent importance-sampling distributions perform

  15. Recruitment of hard-to-reach population subgroups via adaptations of the snowball sampling strategy.

    Science.gov (United States)

    Sadler, Georgia Robins; Lee, Hau-Chen; Lim, Rod Seung-Hwan; Fullerton, Judith

    2010-09-01

    Nurse researchers and educators often engage in outreach to narrowly defined populations. This article offers examples of how variations on the snowball sampling recruitment strategy can be applied in the creation of culturally appropriate, community-based information dissemination efforts related to recruitment to health education programs and research studies. Examples from the primary author's program of research are provided to demonstrate how adaptations of snowball sampling can be used effectively in the recruitment of members of traditionally underserved or vulnerable populations. The adaptation of snowball sampling techniques, as described in this article, helped the authors to gain access to each of the more-vulnerable population groups of interest. The use of culturally sensitive recruitment strategies is both appropriate and effective in enlisting the involvement of members of vulnerable populations. Adaptations of snowball sampling strategies should be considered when recruiting participants for education programs or for research studies when the recruitment of a population-based sample is not essential.

  16. Adaptive Biasing Combined with Hamiltonian Replica Exchange to Improve Umbrella Sampling Free Energy Simulations.

    Science.gov (United States)

    Zeller, Fabian; Zacharias, Martin

    2014-02-11

    The accurate calculation of potentials of mean force for ligand-receptor binding is one of the most important applications of molecular simulation techniques. Typically, the separation distance between ligand and receptor is chosen as a reaction coordinate along which a PMF can be calculated with the aid of umbrella sampling (US) techniques. In addition, restraints can be applied on the relative position and orientation of the partner molecules to reduce accessible phase space. An approach combining such phase space reduction with flattening of the free energy landscape and configurational exchanges has been developed, which significantly improves the convergence of PMF calculations in comparison with standard umbrella sampling. The free energy surface along the reaction coordinate is smoothened by iteratively adapting biasing potentials corresponding to previously calculated PMFs. Configurations are allowed to exchange between the umbrella simulation windows via the Hamiltonian replica exchange method. The application to a DNA molecule in complex with a minor groove binding ligand indicates significantly improved convergence and complete reversibility of the sampling along the pathway. The calculated binding free energy is in excellent agreement with experimental results. In contrast, the application of standard US resulted in large differences between PMFs calculated for association and dissociation pathways. The approach could be a useful alternative to standard US for computational studies on biomolecular recognition processes.

  17. RF Sub-sampling Receiver Architecture based on Milieu Adapting Techniques

    DEFF Research Database (Denmark)

    Behjou, Nastaran; Larsen, Torben; Jensen, Ole Kiel

    2012-01-01

    A novel sub-sampling based architecture is proposed which has the ability of reducing the problem of image distortion and improving the signal to noise ratio significantly. The technique is based on sensing the environment and adapting the sampling rate of the receiver to the best possible...

  18. Parks, people, and change: the importance of multistakeholder engagement in adaptation planning for conserved areas

    Directory of Open Access Journals (Sweden)

    Corrine N. Knapp

    2014-12-01

    Full Text Available Climate change challenges the traditional goals and conservation strategies of protected areas, necessitating adaptation to changing conditions. Denali National Park and Preserve (Denali in south central Alaska, USA, is a vast landscape that is responding to climate change in ways that will impact both ecological resources and local communities. Local observations help to inform understanding of climate change and adaptation planning, but whose knowledge is most important to consider? For this project we interviewed long-term Denali staff, scientists, subsistence community members, bus drivers, and business owners to assess what types of observations each can contribute, how climate change is impacting each, and what they think the National Park Service should do to adapt. The project shows that each type of long-term observer has different types of observations, but that those who depend more directly on natural resources for their livelihoods have more and different observations than those who do not. These findings suggest that engaging multiple groups of stakeholders who interact with the park in distinct ways adds substantially to the information provided by Denali staff and scientists and offers a broader foundation for adaptation planning. It also suggests that traditional protected area paradigms that fail to learn from and foster appropriate engagement of people may be maladaptive in the context of climate change.

  19. Hybrid algorithm of ensemble transform and importance sampling for assimilation of non-Gaussian observations

    Directory of Open Access Journals (Sweden)

    Shin'ya Nakano

    2014-05-01

    Full Text Available A hybrid algorithm that combines the ensemble transform Kalman filter (ETKF and the importance sampling approach is proposed. Since the ETKF assumes a linear Gaussian observation model, the estimate obtained by the ETKF can be biased in cases with nonlinear or non-Gaussian observations. The particle filter (PF is based on the importance sampling technique, and is applicable to problems with nonlinear or non-Gaussian observations. However, the PF usually requires an unrealistically large sample size in order to achieve a good estimation, and thus it is computationally prohibitive. In the proposed hybrid algorithm, we obtain a proposal distribution similar to the posterior distribution by using the ETKF. A large number of samples are then drawn from the proposal distribution, and these samples are weighted to approximate the posterior distribution according to the importance sampling principle. Since the importance sampling provides an estimate of the probability density function (PDF without assuming linearity or Gaussianity, we can resolve the bias due to the nonlinear or non-Gaussian observations. Finally, in the next forecast step, we reduce the sample size to achieve computational efficiency based on the Gaussian assumption, while we use a relatively large number of samples in the importance sampling in order to consider the non-Gaussian features of the posterior PDF. The use of the ETKF is also beneficial in terms of the computational simplicity of generating a number of random samples from the proposal distribution and in weighting each of the samples. The proposed algorithm is not necessarily effective in case that the ensemble is located distant from the true state. However, monitoring the effective sample size and tuning the factor for covariance inflation could resolve this problem. In this paper, the proposed hybrid algorithm is introduced and its performance is evaluated through experiments with non-Gaussian observations.

  20. Statistical evaluation of the New Zealand food safety authority sampling protocol for imported food.

    Science.gov (United States)

    Govindaraju, Kondaswamy; Bebbington, Mark; Wrathall, Thewaporn

    2010-05-01

    The New Zealand Food Safety Authority sampling protocol for compliance inspection of imported food products is evaluated for its ability to provide consumer protection. The sampling protocol involves both partial testing of imported consignments and complete skipping inspection of consignments based on the quality history. The risk posed by the strategies of partial testing and skipping inspection of imports is evaluated using the average outgoing quality limit and other performance measures. The cost dimension of sampling inspection is also considered. Suggestions for improvement, which include tightening the skipping inspection parameters, are made.

  1. Importance of Interaction between Integrin and Actin Cytoskeleton in Suspension Adaptation of CHO cells.

    Science.gov (United States)

    Walther, Christa G; Whitfield, Robert; James, David C

    2016-04-01

    The biopharmaceutical production process relies upon mammalian cell technology where single cells proliferate in suspension in a chemically defined synthetic environment. This environment lacks exogenous growth factors, usually contributing to proliferation of fibroblastic cell types such as Chinese hamster ovary (CHO) cells. Use of CHO cells for production hence requires a lengthy 'adaptation' process to select clones capable of proliferation as single cells in suspension. The underlying molecular changes permitting proliferation in suspension are not known. Comparison of the non-suspension-adapted clone CHO-AD and a suspension-adapted propriety cell line CHO-SA by flow cytometric analysis revealed a highly variable bi-modal expression pattern for cell-to-cell contact proteins in contrast to the expression pattern seen for integrins. Those have a uni-modal expression on suspension and adherent cells. Integrins showed a conformation distinguished by regularly distributed clusters forming a sphere on the cell membrane of suspension-adapted cells. Actin cytoskeleton analysis revealed reorganisation from the typical fibrillar morphology found in adherent cells to an enforced spherical subcortical actin sheath in suspension cells. The uni-modal expression and specific clustering of integrins could be confirmed for CHO-S, another suspension cell line. Cytochalasin D treatment resulted in breakdown of the actin sheath and the sphere-like integrin conformation demonstrating the link between integrins and actin in suspension-adapted CHO cells. The data demonstrates the importance of signalling changes, leading to an integrin rearrangement on the cell surface, and the necessity of the reinforcement of the actin cytoskeleton for proliferation in suspension conditions.

  2. Adaptive sampling based on the cumulative distribution function of order statistics to delineate heavy-metal contaminated soils using kriging

    Energy Technology Data Exchange (ETDEWEB)

    Juang, K.-W. [Department of Post-Modern Agriculture, MingDao University, Pitou, Changhua, Taiwan (China); Lee, D.-Y. [Graduate Institute of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan (China)]. E-mail: dylee@ccms.ntu.edu.tw; Teng, Y.-L. [Graduate Institute of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan (China)

    2005-11-15

    Correctly classifying 'contaminated' areas in soils, based on the threshold for a contaminated site, is important for determining effective clean-up actions. Pollutant mapping by means of kriging is increasingly being used for the delineation of contaminated soils. However, those areas where the kriged pollutant concentrations are close to the threshold have a high possibility for being misclassified. In order to reduce the misclassification due to the over- or under-estimation from kriging, an adaptive sampling using the cumulative distribution function of order statistics (CDFOS) was developed to draw additional samples for delineating contaminated soils, while kriging. A heavy-metal contaminated site in Hsinchu, Taiwan was used to illustrate this approach. The results showed that compared with random sampling, adaptive sampling using CDFOS reduced the kriging estimation errors and misclassification rates, and thus would appear to be a better choice than random sampling, as additional sampling is required for delineating the 'contaminated' areas. - A sampling approach was derived for drawing additional samples while kriging.

  3. Iterative Monte Carlo with bead-adapted sampling for complex-time correlation functions

    Science.gov (United States)

    Jadhao, Vikram; Makri, Nancy

    2010-03-01

    In a recent communication [V. Jadhao and N. Makri, J. Chem. Phys. 129, 161102 (2008)], we introduced an iterative Monte Carlo (IMC) path integral methodology for calculating complex-time correlation functions. This method constitutes a stepwise evaluation of the path integral on a grid selected by a Monte Carlo procedure, circumventing the exponential growth of statistical error with increasing propagation time, while realizing the advantageous scaling of importance sampling in the grid selection and integral evaluation. In the present paper, we present an improved formulation of IMC, which is based on a bead-adapted sampling procedure; thus leading to grid point distributions that closely resemble the absolute value of the integrand at each iteration. We show that the statistical error of IMC does not grow upon repeated iteration, in sharp contrast to the performance of the conventional path integral approach which leads to exponential increase in statistical uncertainty. Numerical results on systems with up to 13 degrees of freedom and propagation up to 30 times the "thermal" time ℏβ /2 illustrate these features.

  4. Implementation of time-efficient adaptive sampling function design for improved undersampled MRI reconstruction.

    Science.gov (United States)

    Choi, Jinhyeok; Kim, Hyeonjin

    2016-12-01

    To improve the efficacy of undersampled MRI, a method of designing adaptive sampling functions is proposed that is simple to implement on an MR scanner and yet effectively improves the performance of the sampling functions. An approximation of the energy distribution of an image (E-map) is estimated from highly undersampled k-space data acquired in a prescan and efficiently recycled in the main scan. An adaptive probability density function (PDF) is generated by combining the E-map with a modeled PDF. A set of candidate sampling functions are then prepared from the adaptive PDF, among which the one with maximum energy is selected as the final sampling function. To validate its computational efficiency, the proposed method was implemented on an MR scanner, and its robust performance in Fourier-transform (FT) MRI and compressed sensing (CS) MRI was tested by simulations and in a cherry tomato. The proposed method consistently outperforms the conventional modeled PDF approach for undersampling ratios of 0.2 or higher in both FT-MRI and CS-MRI. To fully benefit from undersampled MRI, it is preferable that the design of adaptive sampling functions be performed online immediately before the main scan. In this way, the proposed method may further improve the efficacy of the undersampled MRI.

  5. Coalescent: an open-science framework for importance sampling in coalescent theory.

    Science.gov (United States)

    Tewari, Susanta; Spouge, John L

    2015-01-01

    Background. In coalescent theory, computer programs often use importance sampling to calculate likelihoods and other statistical quantities. An importance sampling scheme can exploit human intuition to improve statistical efficiency of computations, but unfortunately, in the absence of general computer frameworks on importance sampling, researchers often struggle to translate new sampling schemes computationally or benchmark against different schemes, in a manner that is reliable and maintainable. Moreover, most studies use computer programs lacking a convenient user interface or the flexibility to meet the current demands of open science. In particular, current computer frameworks can only evaluate the efficiency of a single importance sampling scheme or compare the efficiencies of different schemes in an ad hoc manner. Results. We have designed a general framework (http://coalescent.sourceforge.net; language: Java; License: GPLv3) for importance sampling that computes likelihoods under the standard neutral coalescent model of a single, well-mixed population of constant size over time following infinite sites model of mutation. The framework models the necessary core concepts, comes integrated with several data sets of varying size, implements the standard competing proposals, and integrates tightly with our previous framework for calculating exact probabilities. For a given dataset, it computes the likelihood and provides the maximum likelihood estimate of the mutation parameter. Well-known benchmarks in the coalescent literature validate the accuracy of the framework. The framework provides an intuitive user interface with minimal clutter. For performance, the framework switches automatically to modern multicore hardware, if available. It runs on three major platforms (Windows, Mac and Linux). Extensive tests and coverage make the framework reliable and maintainable. Conclusions. In coalescent theory, many studies of computational efficiency consider only

  6. Cross-entropy optimisation of importance sampling parameters for statistical model checking

    CERN Document Server

    Jégourel, Cyrille; Sedwards, Sean

    2012-01-01

    Statistical model checking avoids the exponential growth of states associated with probabilistic model checking by estimating properties from multiple executions of a system and by giving results within confidence bounds. Rare properties are often very important but pose a particular challenge for simulation-based approaches, hence a key objective under these circumstances is to reduce the number and length of simulations necessary to produce a given level of confidence. Importance sampling is a well-established technique that achieves this, however to maintain the advantages of statistical model checking it is necessary to find good importance sampling distributions without considering the entire state space. Motivated by the above, we present a simple algorithm that uses the notion of cross-entropy to find the optimal parameters for an importance sampling distribution. In contrast to previous work, our algorithm uses a low dimensional vector of parameters to define this distribution and thus avoids the ofte...

  7. Data reduction in the ITMS system through a data acquisition model with self-adaptive sampling rate

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, M. [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid (UPM), Crta. Valencia Km-7, Madrid 28031 (Spain)], E-mail: mariano.ruiz@upm.es; Lopez, JM.; Arcas, G. de [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid (UPM), Crta. Valencia Km-7, Madrid 28031 (Spain); Barrera, E. [Departamento de Sistemas Electronicos y de Control, Universidad Politecnica de Madrid (UPM), Crta. Valencia Km-7, Madrid 28031 (Spain); Melendez, R. [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid (UPM), Crta. Valencia Km-7, Madrid 28031 (Spain); Vega, J. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain)

    2008-04-15

    Long pulse or steady state operation of fusion experiments require data acquisition and processing systems that reduce the volume of data involved. The availability of self-adaptive sampling rate systems and the use of real-time lossless data compression techniques can help solve these problems. The former is important for continuous adaptation of sampling frequency for experimental requirements. The latter allows the maintenance of continuous digitization under limited memory conditions. This can be achieved by permanent transmission of compressed data to other systems. The compacted transfer ensures the use of minimum bandwidth. This paper presents an implementation based on intelligent test and measurement system (ITMS), a data acquisition system architecture with multiprocessing capabilities that permits it to adapt the system's sampling frequency throughout the experiment. The sampling rate can be controlled depending on the experiment's specific requirements by using an external dc voltage signal or by defining user events through software. The system takes advantage of the high processing capabilities of the ITMS platform to implement a data reduction mechanism based in lossless data compression algorithms which are themselves based in periodic deltas.

  8. Estimating and Projecting Trends in HIV/AIDS Generalized Epidemics Using Incremental Mixture Importance Sampling.

    Science.gov (United States)

    Raftery, Adrian E; Bao, Le

    2010-12-01

    The Joint United Nations Programme on HIV/AIDS (UNAIDS) has decided to use Bayesian melding as the basis for its probabilistic projections of HIV prevalence in countries with generalized epidemics. This combines a mechanistic epidemiological model, prevalence data, and expert opinion. Initially, the posterior distribution was approximated by sampling-importance-resampling, which is simple to implement, easy to interpret, transparent to users, and gave acceptable results for most countries. For some countries, however, this is not computationally efficient because the posterior distribution tends to be concentrated around nonlinear ridges and can also be multimodal. We propose instead incremental mixture importance sampling (IMIS), which iteratively builds up a better importance sampling function. This retains the simplicity and transparency of sampling importance resampling, but is much more efficient computationally. It also leads to a simple estimator of the integrated likelihood that is the basis for Bayesian model comparison and model averaging. In simulation experiments and on real data, it outperformed both sampling importance resampling and three publicly available generic Markov chain Monte Carlo algorithms for this kind of problem.

  9. Career Adapt-Abilities Scale in a French-Speaking Swiss Sample: Psychometric Properties and Relationships to Personality and Work Engagement

    Science.gov (United States)

    Rossier, Jerome; Zecca, Gregory; Stauffer, Sarah D.; Maggiori, Christian; Dauwalder, Jean-Pierre

    2012-01-01

    The aim of this study was to analyze the psychometric properties of the Career Adapt-Abilities Scale (CAAS) in a French-speaking Swiss sample and its relationship with personality dimensions and work engagement. The heterogeneous sample of 391 participants (M[subscript age] = 39.59, SD = 12.30) completed the CAAS-International and a short version…

  10. Dynamically optimized Wang-Landau sampling with adaptive trial moves and modification factors.

    Science.gov (United States)

    Koh, Yang Wei; Lee, Hwee Kuan; Okabe, Yutaka

    2013-11-01

    The density of states of continuous models is known to span many orders of magnitudes at different energies due to the small volume of phase space near the ground state. Consequently, the traditional Wang-Landau sampling which uses the same trial move for all energies faces difficulties sampling the low-entropic states. We developed an adaptive variant of the Wang-Landau algorithm that very effectively samples the density of states of continuous models across the entire energy range. By extending the acceptance ratio method of Bouzida, Kumar, and Swendsen such that the step size of the trial move and acceptance rate are adapted in an energy-dependent fashion, the random walker efficiently adapts its sampling according to the local phase space structure. The Wang-Landau modification factor is also made energy dependent in accordance with the step size, enhancing the accumulation of the density of states. Numerical simulations show that our proposed method performs much better than the traditional Wang-Landau sampling.

  11. Sample based 3D face reconstruction from a single frontal image by adaptive locally linear embedding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; ZHUANG Yue-ting

    2007-01-01

    In this paper, we propose a highly automatic approach for 3D photorealistic face reconstruction from a single frontal image. The key point of our work is the implementation of adaptive manifold learning approach. Beforehand, an active appearance model (AAM) is trained for automatic feature extraction and adaptive locally linear embedding (ALLE) algorithm is utilized to reduce the dimensionality of the 3D database. Then, given an input frontal face image, the corresponding weights between 3D samples and the image are synthesized adaptively according to the AAM selected facial features. Finally, geometry reconstruction is achieved by linear weighted combination of adaptively selected samples. Radial basis function (RBF) is adopted to map facial texture from the frontal image to the reconstructed face geometry. The texture of invisible regions between the face and the ears is interpolated by sampling from the frontal image. This approach has several advantages: (1) Only a single frontal face image is needed for highly automatic face reconstruction; (2) Compared with former works, our reconstruction approach provides higher accuracy; (3) Constraint based RBF texture mapping provides natural appearance for reconstructed face.

  12. Local Adaptation in European Firs Assessed through Extensive Sampling across Altitudinal Gradients in Southern Europe

    Science.gov (United States)

    Postolache, Dragos; Lascoux, Martin; Drouzas, Andreas D.; Källman, Thomas; Leonarduzzi, Cristina; Liepelt, Sascha; Piotti, Andrea; Popescu, Flaviu; Roschanski, Anna M.; Zhelev, Peter; Fady, Bruno; Vendramin, Giovanni Giuseppe

    2016-01-01

    Background Local adaptation is a key driver of phenotypic and genetic divergence at loci responsible for adaptive traits variations in forest tree populations. Its experimental assessment requires rigorous sampling strategies such as those involving population pairs replicated across broad spatial scales. Methods A hierarchical Bayesian model of selection (HBM) that explicitly considers both the replication of the environmental contrast and the hierarchical genetic structure among replicated study sites is introduced. Its power was assessed through simulations and compared to classical ‘within-site’ approaches (FDIST, BAYESCAN) and a simplified, within-site, version of the model introduced here (SBM). Results HBM demonstrates that hierarchical approaches are very powerful to detect replicated patterns of adaptive divergence with low false-discovery (FDR) and false-non-discovery (FNR) rates compared to the analysis of different sites separately through within-site approaches. The hypothesis of local adaptation to altitude was further addressed by analyzing replicated Abies alba population pairs (low and high elevations) across the species’ southern distribution range, where the effects of climatic selection are expected to be the strongest. For comparison, a single population pair from the closely related species A. cephalonica was also analyzed. The hierarchical model did not detect any pattern of adaptive divergence to altitude replicated in the different study sites. Instead, idiosyncratic patterns of local adaptation among sites were detected by within-site approaches. Conclusion Hierarchical approaches may miss idiosyncratic patterns of adaptation among sites, and we strongly recommend the use of both hierarchical (multi-site) and classical (within-site) approaches when addressing the question of adaptation across broad spatial scales. PMID:27392065

  13. Profit based phase II sample size determination when adaptation by design is adopted

    OpenAIRE

    Martini, D.

    2014-01-01

    Background. Adaptation by design consists in conservatively estimating the phase III sample size on the basis of phase II data, and can be applied in almost all therapeutic areas; it is based on the assumption that the effect size of the drug is the same in phase II and phase III trials, that is a very common scenario assumed in product development. Adaptation by design reduces the probability on underpowered experiments and can improve the overall success probability of phase II and III tria...

  14. Rare-event simulation for tandem queues: A simple and efficient importance sampling scheme

    NARCIS (Netherlands)

    Miretskiy, D.; Scheinhardt, W.; Mandjes, M.

    2009-01-01

    This paper focuses on estimating the rare event of overflow in the downstream queue of a tandem Jackson queue, relying on importance sampling. It is known that in this setting ‘traditional’ state-independent schemes perform poorly. More sophisticated state-dependent schemes yield asymptotic efficien

  15. Efficient Importance Sampling Heuristics for the Simulation of Population Overflow in Feed-Forward Queueing Networks

    NARCIS (Netherlands)

    Nicola, Victor F.; Zaburnenko, Tatiana S.

    2006-01-01

    In this paper we propose a state-dependent importance sampling heuristic to estimate the probability of population overflow in feed-forward networks. This heuristic attempts to approximate the “optimal” state-dependent change of measure without the need for difficult analysis or costly optimization i

  16. Resampling: An improvement of importance sampling in varying population size models.

    Science.gov (United States)

    Merle, C; Leblois, R; Rousset, F; Pudlo, P

    2017-04-01

    Sequential importance sampling algorithms have been defined to estimate likelihoods in models of ancestral population processes. However, these algorithms are based on features of the models with constant population size, and become inefficient when the population size varies in time, making likelihood-based inferences difficult in many demographic situations. In this work, we modify a previous sequential importance sampling algorithm to improve the efficiency of the likelihood estimation. Our procedure is still based on features of the model with constant size, but uses a resampling technique with a new resampling probability distribution depending on the pairwise composite likelihood. We tested our algorithm, called sequential importance sampling with resampling (SISR) on simulated data sets under different demographic cases. In most cases, we divided the computational cost by two for the same accuracy of inference, in some cases even by one hundred. This study provides the first assessment of the impact of such resampling techniques on parameter inference using sequential importance sampling, and extends the range of situations where likelihood inferences can be easily performed.

  17. Importance Sampling Simulation of Population Overflow in Two-node Tandem Networks

    NARCIS (Netherlands)

    Nicola, Victor F.; Zaburnenko, Tatiana S.; Baier, C.; Chiola, G.; Smirni, E.

    2005-01-01

    In this paper we consider the application of importance sampling in simulations of Markovian tandem networks in order to estimate the probability of rare events, such as network population overflow. We propose a heuristic methodology to obtain a good approximation to the 'optimal' state-dependent ch

  18. Importance sampling for Lambda-coalescents in the infinitely many sites model

    CERN Document Server

    Birkner, Matthias; Steinruecken, Matthias; 10.1016/j.tpb.2011.01.005

    2011-01-01

    We present and discuss new importance sampling schemes for the approximate computation of the sample probability of observed genetic types in the infinitely many sites model from population genetics. More specifically, we extend the 'classical framework', where genealogies are assumed to be governed by Kingman's coalescent, to the more general class of Lambda-coalescents and develop further Hobolth et. al.'s (2008) idea of deriving importance sampling schemes based on 'compressed genetrees'. The resulting schemes extend earlier work by Griffiths and Tavar\\'e (1994), Stephens and Donnelly (2000), Birkner and Blath (2008) and Hobolth et. al. (2008). We conclude with a performance comparison of classical and new schemes for Beta- and Kingman coalescents.

  19. Adaptation to climate change and climate variability in European agriculture: The importance of farm level responses

    NARCIS (Netherlands)

    Reidsma, P.; Ewert, F.; Oude Lansink, A.G.J.M.; Leemans, R.

    2010-01-01

    Climatic conditions and hence climate change influence agriculture. Most studies that addressed the vulnerability of agriculture to climate change have focused on potential impacts without considering adaptation. When adaptation strategies are considered, socio-economic conditions and farm managemen

  20. Adaptation to climate change and climate variability:The importance of understanding agriculture as performance

    NARCIS (Netherlands)

    Crane, T.A.; Roncoli, C.; Hoogenboom, G.

    2011-01-01

    Most climate change studies that address potential impacts and potential adaptation strategies are largely based on modelling technologies. While models are useful for visualizing potential future outcomes and evaluating options for potential adaptation, they do not adequately represent and integrat

  1. FloodNet: Coupling Adaptive Sampling with Energy Aware Routing in a Flood Warning System

    Institute of Scientific and Technical Information of China (English)

    Jing Zhou; David De Roure

    2007-01-01

    We describe the design of FloodNet, a flood warning system, which uses a grid-based flood predictor model developed by environmental experts to make flood predictions based on readings of water level collected by a set of sensor nodes.To optimize battery consumption, the reporting frequency of sensor nodes is required to be adaptive to local conditions as well as the flood predictor model.We therefore propose an energy aware routing protocol which allows sensor nodes to consume energy according to this need.This system is notable both for the adaptive sampling regime and the methodology adopted in the design of the adaptive behavior, which involved development of simulation tools and very close collaboration with environmental experts.

  2. Improved Algorithms and Coupled Neutron-Photon Transport for Auto-Importance Sampling Method

    CERN Document Server

    Wang, Xin; Qiu, Rui; Li, Chun-Yan; Liang, Man-Chun; Zhang, Hui; Li, Jun-Li

    2016-01-01

    Auto-Importance Sampling (AIS) method is a Monte Carlo variance reduction technique proposed by Tsinghua University for deep penetration problem, which can improve computational efficiency significantly without pre-calculations for importance distribution. However AIS method is only validated with several basic deep penetration problems of simple geometries and cannot be used for coupled neutron-photon transport. This paper firstly presented the latest algorithm improvements for AIS method including particle transport, fictitious particles creation and adjustment, fictitious surface geometry, random number allocation and calculation of estimated relative error, which made AIS method applicable to complicated deep penetration problem. Then, a coupled Neutron-Photon Auto-Importance Sampling (NP-AIS) method was proposed to apply AIS method with the improved algorithms in coupled neutron-photon Monte Carlo transport. Finally, the NUREG/CR-6115 PWR benchmark model was calculated with the method of geometry splitti...

  3. Assessing employability capacities and career adaptability in a sample of human resource professionals

    Directory of Open Access Journals (Sweden)

    Melinde Coetzee

    2015-03-01

    Full Text Available Orientation: Employers have come to recognise graduates’ employability capacities and their ability to adapt to new work demands as important human capital resources for sustaining a competitive business advantage.Research purpose: The study sought (1 to ascertain whether a significant relationship exists between a set of graduate employability capacities and a set of career adaptability capacities and (2 to identify the variables that contributed the most to this relationship.Motivation for the study: Global competitive markets and technological advances are increasingly driving the demand for graduate knowledge and skills in a wide variety of jobs. Contemporary career theory further emphasises career adaptability across the lifespan as a critical skill for career management agency. Despite the apparent importance attached to employees’ employability and career adaptability, there seems to be a general lack of research investigating the association between these constructs.Research approach, design and method: A cross-sectional, quantitative research design approach was followed. Descriptive statistics, Pearson product-moment correlations and canonical correlation analysis were performed to achieve the objective of the study. The participants (N = 196 were employed in professional positions in the human resource field and were predominantly early career black people and women.Main findings: The results indicated positive multivariate relationships between the variables and showed that lifelong learning capacities and problem solving, decision-making and interactive skills contributed the most to explaining the participants’ career confidence, career curiosity and career control.Practical/managerial implications: The study suggests that developing professional graduates’ employability capacities may strengthen their career adaptability. These capacities were shown to explain graduates’ active engagement in career management strategies

  4. Sample selection and adaptive weight allocation for compressive MIMO UWB noise radar

    Science.gov (United States)

    Kwon, Yangsoo; Narayanan, Ram M.; Rangaswamy, Muralidhar

    2012-06-01

    In this paper, we propose a sample selection method for compressive multiple-input multiple-output (MIMO) ultra-wideband (UWB) noise radar imaging. The proposed sample selection is based on comparing norm values of the transmitted sequences, and selects the largest M samples among N candidates per antenna. Moreover, we propose an adaptive weight allocation which improves normalized mean-square error (NMSE) by maximizing the mutual information between target echoes and the transmitted signals. Further, this weighting scheme is applicable to both sample selection schemes, a conventional random sampling and the proposed selection. Simulations show that the proposed selection method can improve the multiple target detection probability and NMSE. Moreover, the proposed weight allocation scheme is applicable to those selection methods and obtains spatial diversity and signal-to-noise ratio (SNR) gains.

  5. Compact Ocean Models Enable Onboard AUV Autonomy and Decentralized Adaptive Sampling

    Science.gov (United States)

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Compact Ocean Models Enable Onboard AUV Autonomy and...Models Enable Onboard AUV Autonomy and Decentralized Adaptive Sampling 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...onboard autonomy of underwater vehicles”, in Proc. AGU Ocean Science Meeting, Salt Lake City, UT. [published] ● Frolov, S., R., Kudela, J., Bellingham

  6. Correlations for the Vineland Adaptive Behavior Scales with Kaufman Brief Intelligence Test in a forensic sample.

    Science.gov (United States)

    Hayes, Susan; Farnill, Douglas

    2003-04-01

    People with an intellectual disability are over-represented in the criminal justice system in many western countries. Identifying accused persons with intellectual disability is important if they are to receive protections available under the law. Accurate diagnosis is also relevant for correctional administrators, probation and parole services, and community services. Diagnosis of intellectual disability must be made on the basis of both cognitive skills (intelligence) and adaptive behavior. In this study, the Kaufman Brief Intelligence Test assessed intelligence, and the Vineland Adaptive Behavior Scales assessed adaptive behavior, through self-report. Tests were administered to 150 offenders, ranging in age from 13 to 53 years, in Australian prisons, juvenile detention centers, legal aid offices, and probation services. Pearson product-moment correlation coefficients calculated among all subtests and between total scores were significant. ROC curve analyses demonstrated that performance on each effectively predicted a standard score of less than 70 on the other one.

  7. Efficient adaptive designs with mid-course sample size adjustment in clinical trials

    CERN Document Server

    Bartroff, Jay

    2011-01-01

    Adaptive designs have been proposed for clinical trials in which the nuisance parameters or alternative of interest are unknown or likely to be misspecified before the trial. Whereas most previous works on adaptive designs and mid-course sample size re-estimation have focused on two-stage or group sequential designs in the normal case, we consider here a new approach that involves at most three stages and is developed in the general framework of multiparameter exponential families. Not only does this approach maintain the prescribed type I error probability, but it also provides a simple but asymptotically efficient sequential test whose finite-sample performance, measured in terms of the expected sample size and power functions, is shown to be comparable to the optimal sequential design, determined by dynamic programming, in the simplified normal mean case with known variance and prespecified alternative, and superior to the existing two-stage designs and also to adaptive group sequential designs when the al...

  8. Improved importance sampling technique for efficient simulation of digital communication systems

    Science.gov (United States)

    Lu, Dingqing; Yao, Kung

    1988-01-01

    A new, improved importance sampling (IIS) approach to simulation is considered. Some basic concepts of IS are introduced, and detailed evolutions of simulation estimation variances for Monte Carlo (MC) and IS simulations are given. The general results obtained from these evolutions are applied to the specific previously known conventional importance sampling (CIS) technique and the new IIS technique. The derivation for a linear system with no signal random memory is considered in some detail. For the CIS technique, the optimum input scaling parameter is found, while for the IIS technique, the optimum translation parameter is found. The results are generalized to a linear system with memory and signals. Specific numerical and simulation results are given which show the advantages of CIS over MC and IIS over CIS for simulations of digital communications systems.

  9. Burnout and Engagement: Relative Importance of Predictors and Outcomes in Two Health Care Worker Samples.

    Science.gov (United States)

    Fragoso, Zachary L; Holcombe, Kyla J; McCluney, Courtney L; Fisher, Gwenith G; McGonagle, Alyssa K; Friebe, Susan J

    2016-06-09

    This study's purpose was twofold: first, to examine the relative importance of job demands and resources as predictors of burnout and engagement, and second, the relative importance of engagement and burnout related to health, depressive symptoms, work ability, organizational commitment, and turnover intentions in two samples of health care workers. Nurse leaders (n = 162) and licensed emergency medical technicians (EMTs; n = 102) completed surveys. In both samples, job demands predicted burnout more strongly than job resources, and job resources predicted engagement more strongly than job demands. Engagement held more weight than burnout for predicting commitment, and burnout held more weight for predicting health outcomes, depressive symptoms, and work ability. Results have implications for the design, evaluation, and effectiveness of workplace interventions to reduce burnout and improve engagement among health care workers. Actionable recommendations for increasing engagement and decreasing burnout in health care organizations are provided.

  10. Self-organizing adaptive map: autonomous learning of curves and surfaces from point samples.

    Science.gov (United States)

    Piastra, Marco

    2013-05-01

    Competitive Hebbian Learning (CHL) (Martinetz, 1993) is a simple and elegant method for estimating the topology of a manifold from point samples. The method has been adopted in a number of self-organizing networks described in the literature and has given rise to related studies in the fields of geometry and computational topology. Recent results from these fields have shown that a faithful reconstruction can be obtained using the CHL method only for curves and surfaces. Within these limitations, these findings constitute a basis for defining a CHL-based, growing self-organizing network that produces a faithful reconstruction of an input manifold. The SOAM (Self-Organizing Adaptive Map) algorithm adapts its local structure autonomously in such a way that it can match the features of the manifold being learned. The adaptation process is driven by the defects arising when the network structure is inadequate, which cause a growth in the density of units. Regions of the network undergo a phase transition and change their behavior whenever a simple, local condition of topological regularity is met. The phase transition is eventually completed across the entire structure and the adaptation process terminates. In specific conditions, the structure thus obtained is homeomorphic to the input manifold. During the adaptation process, the network also has the capability to focus on the acquisition of input point samples in critical regions, with a substantial increase in efficiency. The behavior of the network has been assessed experimentally with typical data sets for surface reconstruction, including suboptimal conditions, e.g. with undersampling and noise.

  11. Importance of impacts scenarios for the adaptation of agriculture to climate change

    Science.gov (United States)

    Zullo, J.; Macedo, C.; Pinto, H. S.; Assad, E. D.; Koga Vicente, A.

    2012-12-01

    The great possibility that the climate is already changing, and the most drastic way possible, increases the challenge of agricultural engineering, especially in environmentally vulnerable areas and in regions where agriculture has a high economic and social importance. Knowledge of potential impacts that may be caused by changes in water and thermal regimes in coming decades is increasingly strategic, as they allow the development of techniques to adapt agriculture to climate change and therefore minimizes the risk of undesirable impacts, for example, in food and nutritional security. Thus, the main objective of this paper is to describe a way to generate impacts scenarios caused by anomalies of precipitation and temperature in the definition of climate risk zoning of an agricultural crop very important in the tropics, such as the sugar cane, especially in central-southern Brazil, which is one of its main world producers. A key point here is the choice of the climate model to be used, considering that 23 different models were used in the fourth IPCC report published in 2007. The number and range of available models requires the definition of criteria for choosing the most suitable for the preparation of the impacts scenarios. One way proposed and used in this work is based on the definition of two groups of models according to 27 technical attributes of them. The clustering of 23 models in two groups, with a model representing each group (UKMO_HadCM3 and MIROC3.2_medres), assists the generation and comparison of impacts scenarios, making them more representative and useful. Another important aspect in the generation of impacts scenarios is the estimate of the relative importance of the anomalies of precipitation and temperature, which are the most commonly used. To assess the relative importance of the anomalies are generated scenarios considering an anomaly at a time and both together. The impacts scenarios for a high emission of greenhouse gases (A2), from 2010

  12. Adapting chain referral methods to sample new migrants: Possibilities and limitations

    Directory of Open Access Journals (Sweden)

    Lucinda Platt

    2015-09-01

    Full Text Available Background: Demographic research on migration requires representative samples of migrant populations. Yet recent immigrants, who are particularly informative about current migrant flows, are difficult to capture even in specialist surveys. Respondent-driven sampling (RDS, a chain referral sampling and analysis technique, potentially offers the opportunity to achieve population-level inference of recently arrived migrant populations. Objective: We evaluate the attempt to use RDS to sample two groups of migrants, from Pakistan and Poland, who had arrived in the UK within the previous 18 months, and we present an alternative approach adapted to recent migrants. Methods: We discuss how connectedness, privacy, clustering, and motivation are expected to differ among recently arrived migrants, compared to typical applications of RDS. We develop a researcher-led chain referral approach, and compare success in recruitment and indicators of representativeness to standard RDS recruitment. Results: Our researcher-led approach led to higher rates of chain-referral, and enabled us to reach population members with smaller network sizes. The researcher-led approach resulted in similar recruiter-recruit transition probabilities to traditional RDS across many demographic and social characteristics. However, we did not succeed in building up long referral chains, largely due to the lack of connectedness of our target populations and some reluctance to refer. There were some differences between the two migrant groups, with less mobile and less hidden Pakistani men producing longer referral chains. Conclusions: Chain referral is difficult to implement for sampling newly arrived migrants. However, our researcher-led adaptation shows promise for less hidden and more stable recent immigrant populations. Contribution: The paper offers an evaluation of RDS for surveying recent immigrants and an adaptation that may be effective under certain conditions.

  13. Social Daydreaming and Adjustment: An Experience-Sampling Study of Socio-Emotional Adaptation During a Life Transition.

    Science.gov (United States)

    Poerio, Giulia L; Totterdell, Peter; Emerson, Lisa-Marie; Miles, Eleanor

    2016-01-01

    Estimates suggest that up to half of waking life is spent daydreaming; that is, engaged in thought that is independent of, and unrelated to, one's current task. Emerging research indicates that daydreams are predominately social suggesting that daydreams may serve socio-emotional functions. Here we explore the functional role of social daydreaming for socio-emotional adjustment during an important and stressful life transition (the transition to university) using experience-sampling with 103 participants over 28 days. Over time, social daydreams increased in their positive characteristics and positive emotional outcomes; specifically, participants reported that their daydreams made them feel more socially connected and less lonely, and that the content of their daydreams became less fanciful and involved higher quality relationships. These characteristics then predicted less loneliness at the end of the study, which, in turn was associated with greater social adaptation to university. Feelings of connection resulting from social daydreams were also associated with less emotional inertia in participants who reported being less socially adapted to university. Findings indicate that social daydreaming is functional for promoting socio-emotional adjustment to an important life event. We highlight the need to consider the social content of stimulus-independent cognitions, their characteristics, and patterns of change, to specify how social thoughts enable socio-emotional adaptation.

  14. Social daydreaming and adjustment: An experience-sampling study of socio-emotional adaptation during a life transition

    Directory of Open Access Journals (Sweden)

    Giulia Lara Poerio

    2016-01-01

    Full Text Available Estimates suggest that up to half of waking life is spent daydreaming; that is, engaged in thought that is independent of, and unrelated to, one’s current task. Emerging research indicates that daydreams are predominately social suggesting that daydreams may serve socio-emotional functions. Here we explore the functional role of social daydreaming for socio-emotional adjustment during an important and stressful life transition (the transition to university using experience-sampling with 103 participants over 28 days. Over time, social daydreams increased in their positive characteristics and positive emotional outcomes; specifically, participants reported that their daydreams made them feel more socially connected and less lonely, and that the content of their daydreams became less fanciful and involved higher quality relationships. These characteristics then predicted less loneliness at the end of the study, which, in turn was associated with greater social adaptation to university. Feelings of connection resulting from social daydreams were also associated with less emotional inertia in participants who reported being less socially adapted to university. Findings indicate that social daydreaming is functional for promoting socio-emotional adjustment to an important life event. We highlight the need to consider the social content of stimulus-independent cognitions, their characteristics, and patterns of change, to specify how social thoughts enable socio-emotional adaptation.

  15. Adaptive sampling strategy support for the unlined chromic acid pit, chemical waste landfill, Sandia National Laboratories, Albuquerque, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.L.

    1993-11-01

    Adaptive sampling programs offer substantial savings in time and money when assessing hazardous waste sites. Key to some of these savings is the ability to adapt a sampling program to the real-time data generated by an adaptive sampling program. This paper presents a two-prong approach to supporting adaptive sampling programs: a specialized object-oriented database/geographical information system (SitePlanner{trademark} ) for data fusion, management, and display and combined Bayesian/geostatistical methods (PLUME) for contamination-extent estimation and sample location selection. This approach is applied in a retrospective study of a subsurface chromium plume at Sandia National Laboratories` chemical waste landfill. Retrospective analyses suggest the potential for characterization cost savings on the order of 60% through a reduction in the number of sampling programs, total number of soil boreholes, and number of samples analyzed from each borehole.

  16. The importance of trabecular hypertrophy in right ventricular adaptation to chronic pressure overload.

    Science.gov (United States)

    van de Veerdonk, Mariëlle C; Dusoswa, Sophie A; Marcus, J Tim; Bogaard, Harm-Jan; Spruijt, Onno; Kind, Taco; Westerhof, Nico; Vonk-Noordegraaf, Anton

    2014-02-01

    To assess the contribution of right ventricular (RV) trabeculae and papillary muscles (TPM) to RV mass and volumes in controls and patients with pulmonary arterial hypertension (PAH). Furthermore, to evaluate whether TPM shows a similar response as the RV free wall (RVFW) to changes in pulmonary artery pressure (PAP) during follow-up. 50 patients underwent cardiac magnetic resonance (CMR) and right heart catheterization at baseline and after one-year follow-up. Furthermore 20 controls underwent CMR. RV masses were assessed with and without TPM. TPM constituted a larger proportion of total RV mass and RV end-diastolic volume (RVEDV) in PAH than in controls (Mass: 35 ± 7 vs. 25 ± 5 %; p TPM mass was related to the RVFW mass in patients (baseline: R = 0.65; p TPM from the assessment resulted in altered RV mass, volumes and function than when included (all p TPM mass (β = 0.44; p = 0.004) but not the changes in RVFW mass (p = 0.095) were independently related to changes in PAP during follow-up. RV TPM showed a larger contribution to total RV mass in PAH (~35 %) compared to controls (~25 %). Inclusion of TPM in the analyses significantly influenced the magnitude of the RV volumes and mass. Furthermore, TPM mass was stronger related to changes in PAP than RVFW mass. Our results implicate that TPM are important contributors to RV adaptation during pressure overload and cannot be neglected from the RV assessment.

  17. Adaptive Sampling approach to environmental site characterization at Joliet Army Ammunition Plant: Phase 2 demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Bujewski, G.E. [Sandia National Labs., Albuquerque, NM (United States). Environmental Restoration Technologies Dept.; Johnson, R.L. [Argonne National Lab., IL (United States)

    1996-04-01

    Adaptive sampling programs provide real opportunities to save considerable time and money when characterizing hazardous waste sites. This Strategic Environmental Research and Development Program (SERDP) project demonstrated two decision-support technologies, SitePlanner{trademark} and Plume{trademark}, that can facilitate the design and deployment of an adaptive sampling program. A demonstration took place at Joliet Army Ammunition Plant (JAAP), and was unique in that it was tightly coupled with ongoing Army characterization work at the facility, with close scrutiny by both state and federal regulators. The demonstration was conducted in partnership with the Army Environmental Center`s (AEC) Installation Restoration Program and AEC`s Technology Development Program. AEC supported researchers from Tufts University who demonstrated innovative field analytical techniques for the analysis of TNT and DNT. SitePlanner{trademark} is an object-oriented database specifically designed for site characterization that provides an effective way to compile, integrate, manage and display site characterization data as it is being generated. Plume{trademark} uses a combination of Bayesian analysis and geostatistics to provide technical staff with the ability to quantitatively merge soft and hard information for an estimate of the extent of contamination. Plume{trademark} provides an estimate of contamination extent, measures the uncertainty associated with the estimate, determines the value of additional sampling, and locates additional samples so that their value is maximized.

  18. Phylogeographic differentiation versus transcriptomic adaptation to warm temperatures in Zostera marina, a globally important seagrass

    NARCIS (Netherlands)

    Jueterbock, Alexander; Franssen, S. U.; Bergmann, N.; Gu, J.; Coyer, J. A.; Reusch, T. B. H.; Bornberg-Bauer, E.; Olsen, J. L.

    2016-01-01

    Populations distributed across a broad thermal cline are instrumental in addressing adaptation to increasing temperatures under global warming. Using a space-for-time substitution design, we tested for parallel adaptation to warm temperatures along two independent thermal clines in Zostera marina, t

  19. Mapping differential elemental accumulation in fish tissues: Importance of fish tissue sampling standardization

    Directory of Open Access Journals (Sweden)

    Jovičić Katarina

    2016-01-01

    Full Text Available The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn in the muscle, gills, liver and intestine of the wels catfish (Silurus glanis from the Danube River were analyzed by inductively coupled plasma mass spectrometry (ICP-MS. The aim of the study was to determine whether in complex muscle/skin, gill filament/gill arch, proximal/distal liver and proximal/median/distal intestine samples, particular components differ in concentrations of the analyzed elements. Results indicated that there were no differences in the accumulation of different elements between the proximal and distal liver segments and between the proximal and median intestine sections. Conversely, elemental accumulation patterns in muscle and skin differed significantly. Significant differences were also observed between the gill arch and filaments, as well as between the distal and the two upper intestine sections. Findings indicated the importance of detailed reporting of tissue sampling, i.e. whether the skin was included in the muscle sample, as well as if the gill arch and filaments were analyzed together. Due to a potential bias that can be produced by different muscle/skin or gill arch/filament ratios included in the sample, we strongly recommend that they should not be analyzed together. Results of the present study might be of interest to the scientific community and stakeholders involved in aquatic ecosystem monitoring programs. [Projekat Ministarstva nauke Republike Srbije, br. TR37009 i br. 173045

  20. Importance sampling method of correction for multiple testing in affected sib-pair linkage analysis

    OpenAIRE

    Klein, Alison P.; Kovac, Ilija; Sorant, Alexa JM; Baffoe-Bonnie, Agnes; Doan, Betty Q; Ibay, Grace; Lockwood, Erica; Mandal, Diptasri; Santhosh, Lekshmi; Weissbecker, Karen; Woo, Jessica; Zambelli-Weiner, April; Zhang, Jie; Naiman, Daniel Q.; Malley, James

    2003-01-01

    Using the Genetic Analysis Workshop 13 simulated data set, we compared the technique of importance sampling to several other methods designed to adjust p-values for multiple testing: the Bonferroni correction, the method proposed by Feingold et al., and naïve Monte Carlo simulation. We performed affected sib-pair linkage analysis for each of the 100 replicates for each of five binary traits and adjusted the derived p-values using each of the correction methods. The type I error rates for each...

  1. High-resolution in-depth imaging of optically cleared thick samples using an adaptive SPIM

    Science.gov (United States)

    Masson, Aurore; Escande, Paul; Frongia, Céline; Clouvel, Grégory; Ducommun, Bernard; Lorenzo, Corinne

    2015-11-01

    Today, Light Sheet Fluorescence Microscopy (LSFM) makes it possible to image fluorescent samples through depths of several hundreds of microns. However, LSFM also suffers from scattering, absorption and optical aberrations. Spatial variations in the refractive index inside the samples cause major changes to the light path resulting in loss of signal and contrast in the deepest regions, thus impairing in-depth imaging capability. These effects are particularly marked when inhomogeneous, complex biological samples are under study. Recently, chemical treatments have been developed to render a sample transparent by homogenizing its refractive index (RI), consequently enabling a reduction of scattering phenomena and a simplification of optical aberration patterns. One drawback of these methods is that the resulting RI of cleared samples does not match the working RI medium generally used for LSFM lenses. This RI mismatch leads to the presence of low-order aberrations and therefore to a significant degradation of image quality. In this paper, we introduce an original optical-chemical combined method based on an adaptive SPIM and a water-based clearing protocol enabling compensation for aberrations arising from RI mismatches induced by optical clearing methods and acquisition of high-resolution in-depth images of optically cleared complex thick samples such as Multi-Cellular Tumour Spheroids.

  2. Adaptive expertise in teamwork environment:the importance of social aspects in expert work and learning

    OpenAIRE

    Pihlaja, K. (Kaisa)

    2016-01-01

    Today’s society and modern working life is in a constant change which poses challenges for professional expertise as well as to educational systems that are expected to produce the future experts. Work tasks are becoming increasingly complex and multifaceted in which domain-specific knowledge and routine expertise may not suffice anymore, but calls for adaptive expertise: the ability to adapt in new and unfamiliar settings, use knowledge flexibly in creating high-quality, innovative solutions...

  3. Adaptive multi-sample-based photoacoustic tomography with imaging quality optimization

    Institute of Scientific and Technical Information of China (English)

    Yuxin Wang; Jie Yuan; Sidan Du; Xiaojun Liu; Guan Xu; Xueding Wang

    2015-01-01

    The energy of light exposed on human skin is compulsively limited for safety reasons which affects the power of photoacoustic (PA) signal and its signal-to-noise ratio (SNR) level.Thus,the final reconstructed PA image quality is degraded.This Letter proposes an adaptive multi-sample-based approach to enhance the SNR of PA signals and in addition,detailed information in rebuilt PA images that used to be buried in the noise can be distinguished.Both ex vivo and in vivo experiments are conducted to validate the effectiveness of our proposed method which provides its potential value in clinical trials.

  4. Future tendencies of climate indicators important for adaptation and mitigation strategies in forestry

    Science.gov (United States)

    Galos, Borbala; Hänsler, Andreas; Gulyas, Krisztina; Bidlo, Andras; Czimber, Kornel

    2014-05-01

    impact analyses and build an important basis of the future adaptation strategies in forestry, agriculture and water management. Funding: The research is supported by the TÁMOP-4.2.2.A-11/1/KONV-2012-0013 and TÁMOP-4.1.1.C-12/1/KONV-2012-0012 (ZENFE) joint EU-national research projects. Keywords: climate indices, climate change impacts, forestry, regional climate modelling

  5. Importance of anthropogenic climate impact, sampling error and urban development in sewer system design.

    Science.gov (United States)

    Egger, C; Maurer, M

    2015-04-15

    Urban drainage design relying on observed precipitation series neglects the uncertainties associated with current and indeed future climate variability. Urban drainage design is further affected by the large stochastic variability of precipitation extremes and sampling errors arising from the short observation periods of extreme precipitation. Stochastic downscaling addresses anthropogenic climate impact by allowing relevant precipitation characteristics to be derived from local observations and an ensemble of climate models. This multi-climate model approach seeks to reflect the uncertainties in the data due to structural errors of the climate models. An ensemble of outcomes from stochastic downscaling allows for addressing the sampling uncertainty. These uncertainties are clearly reflected in the precipitation-runoff predictions of three urban drainage systems. They were mostly due to the sampling uncertainty. The contribution of climate model uncertainty was found to be of minor importance. Under the applied greenhouse gas emission scenario (A1B) and within the period 2036-2065, the potential for urban flooding in our Swiss case study is slightly reduced on average compared to the reference period 1981-2010. Scenario planning was applied to consider urban development associated with future socio-economic factors affecting urban drainage. The impact of scenario uncertainty was to a large extent found to be case-specific, thus emphasizing the need for scenario planning in every individual case. The results represent a valuable basis for discussions of new drainage design standards aiming specifically to include considerations of uncertainty.

  6. The importance of training strategy adaptation: a learner-oriented approach for improving older adults' memory and transfer.

    Science.gov (United States)

    Bottiroli, Sara; Cavallini, Elena; Dunlosky, John; Vecchi, Tomaso; Hertzog, Christopher

    2013-09-01

    We investigated the benefits of strategy-adaptation training for promoting transfer effects. This learner-oriented approach--which directly encourages the learner to generalize strategic behavior to new tasks--helps older adults appraise new tasks and adapt trained strategies to them. In Experiment 1, older adults in a strategy-adaptation training group used 2 strategies (imagery and sentence generation) while practicing 2 tasks (list and associative learning); they were then instructed on how to do a simple task analysis to help them adapt the trained strategies for 2 different unpracticed tasks (place learning and text learning) that were discussed during training. Two additional criterion tasks (name-face associative learning and grocery-list learning) were never mentioned during training. Two other groups were included: A strategy training group (who received strategy training and transfer instructions but not strategy-adaptation training) and a waiting-list control group. Both training procedures enhanced older adults' performance on the trained tasks and those tasks that were discussed during training, but transfer was greatest after strategy-adaptation training. Experiment 2 found that strategy-adaptation training conducted via a manual that older adults used at home also promoted transfer. These findings demonstrate the importance of adopting a learner-oriented approach to promote transfer of strategy training.

  7. Improved algorithms and coupled neutron-photon transport for auto-importance sampling method

    Science.gov (United States)

    Wang, Xin; Li, Jun-Li; Wu, Zhen; Qiu, Rui; Li, Chun-Yan; Liang, Man-Chun; Zhang, Hui; Gang, Zhi; Xu, Hong

    2017-01-01

    The Auto-Importance Sampling (AIS) method is a Monte Carlo variance reduction technique proposed for deep penetration problems, which can significantly improve computational efficiency without pre-calculations for importance distribution. However, the AIS method is only validated with several simple examples, and cannot be used for coupled neutron-photon transport. This paper presents improved algorithms for the AIS method, including particle transport, fictitious particle creation and adjustment, fictitious surface geometry, random number allocation and calculation of the estimated relative error. These improvements allow the AIS method to be applied to complicated deep penetration problems with complex geometry and multiple materials. A Completely coupled Neutron-Photon Auto-Importance Sampling (CNP-AIS) method is proposed to solve the deep penetration problems of coupled neutron-photon transport using the improved algorithms. The NUREG/CR-6115 PWR benchmark was calculated by using the methods of CNP-AIS, geometry splitting with Russian roulette and analog Monte Carlo, respectively. The calculation results of CNP-AIS are in good agreement with those of geometry splitting with Russian roulette and the benchmark solutions. The computational efficiency of CNP-AIS for both neutron and photon is much better than that of geometry splitting with Russian roulette in most cases, and increased by several orders of magnitude compared with that of the analog Monte Carlo. Supported by the subject of National Science and Technology Major Project of China (2013ZX06002001-007, 2011ZX06004-007) and National Natural Science Foundation of China (11275110, 11375103)

  8. Adaptive Kalman Filter Based on Adjustable Sampling Interval in Burst Detection for Water Distribution System

    Directory of Open Access Journals (Sweden)

    Doo Yong Choi

    2016-04-01

    Full Text Available Rapid detection of bursts and leaks in water distribution systems (WDSs can reduce the social and economic costs incurred through direct loss of water into the ground, additional energy demand for water supply, and service interruptions. Many real-time burst detection models have been developed in accordance with the use of supervisory control and data acquisition (SCADA systems and the establishment of district meter areas (DMAs. Nonetheless, no consideration has been given to how frequently a flow meter measures and transmits data for predicting breaks and leaks in pipes. This paper analyzes the effect of sampling interval when an adaptive Kalman filter is used for detecting bursts in a WDS. A new sampling algorithm is presented that adjusts the sampling interval depending on the normalized residuals of flow after filtering. The proposed algorithm is applied to a virtual sinusoidal flow curve and real DMA flow data obtained from Jeongeup city in South Korea. The simulation results prove that the self-adjusting algorithm for determining the sampling interval is efficient and maintains reasonable accuracy in burst detection. The proposed sampling method has a significant potential for water utilities to build and operate real-time DMA monitoring systems combined with smart customer metering systems.

  9. Sheet metal hardening curve determined by laminated sample and its adaptability to sheet forming processes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The hardening curve for sheet metal can be determined from the load-displacement curve of tensilespecimen with rectangular cross-section. Therefore, uniaxial compression test on cylinder specimen made from laminated sample is put forward. Considering the influence of anisotropy on hardening properties and the stress state in popular forming process, plane strain compression test on cubic specimen made from laminated sample was advanced. Results show that the deformation range of hardening curves obtained from the presented methods is wide, which meets the need for the application in sheet metal forming processes. In view of the characteristics of methods presented in the paper and the stress strain state of various forming processes, the adaptability of the two methods presented in this paper is given.

  10. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors.

    Science.gov (United States)

    Srbinovski, Bruno; Magno, Michele; Edwards-Murphy, Fiona; Pakrashi, Vikram; Popovici, Emanuel

    2016-03-28

    Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN) are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA) for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind). Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA) in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources) and power hungry sensors (ultrasonic wind sensor and gas sensors). The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

  11. Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers.

    Science.gov (United States)

    Lu, George J; Opella, Stanley J

    2013-08-28

    One of the main applications of solid-state NMR is to study the structure and dynamics of biopolymers, such as membrane proteins, under physiological conditions where the polypeptides undergo global motions as they do in biological membranes. The effects of NMR radiofrequency irradiations on nuclear spins are strongly influenced by these motions. For example, we previously showed that the MSHOT-Pi4 pulse sequence yields spectra with resonance line widths about half of those observed using the conventional pulse sequence when applied to membrane proteins undergoing rapid uniaxial rotational diffusion in phospholipid bilayers. In contrast, the line widths were not changed in microcrystalline samples where the molecules did not undergo global motions. Here, we demonstrate experimentally and describe analytically how some Hamiltonian terms are susceptible to sample motions, and it is their removal through the critical π/2 Z-rotational symmetry that confers the "motion adapted" property to the MSHOT-Pi4 pulse sequence. This leads to the design of separated local field pulse sequence "Motion-adapted SAMPI4" and is generalized to an approach for the design of decoupling sequences whose performance is superior in the presence of molecular motions. It works by cancelling the spin interaction by explicitly averaging the reduced Wigner matrix to zero, rather than utilizing the 2π nutation to average spin interactions. This approach is applicable to both stationary and magic angle spinning solid-state NMR experiments.

  12. Estimation variance bounds of importance sampling simulations in digital communication systems

    Science.gov (United States)

    Lu, D.; Yao, K.

    1991-01-01

    In practical applications of importance sampling (IS) simulation, two basic problems are encountered, that of determining the estimation variance and that of evaluating the proper IS parameters needed in the simulations. The authors derive new upper and lower bounds on the estimation variance which are applicable to IS techniques. The upper bound is simple to evaluate and may be minimized by the proper selection of the IS parameter. Thus, lower and upper bounds on the improvement ratio of various IS techniques relative to the direct Monte Carlo simulation are also available. These bounds are shown to be useful and computationally simple to obtain. Based on the proposed technique, one can readily find practical suboptimum IS parameters. Numerical results indicate that these bounding techniques are useful for IS simulations of linear and nonlinear communication systems with intersymbol interference in which bit error rate and IS estimation variances cannot be obtained readily using prior techniques.

  13. A hybrid algorithm for reliability analysis combining Kriging and subset simulation importance sampling

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Cao; Sun, Zhili; Zhao, Qianli; Wang, Qibin [Northeastern University, Shenyang (China); Wang, Shuang [Jiangxi University of Science and Technology, Ganzhou (China)

    2015-08-15

    To solve the problem of large computation when failure probability with time-consuming numerical model is calculated, we propose an improved active learning reliability method called AK-SSIS based on AK-IS algorithm. First, an improved iterative stopping criterion in active learning is presented so that iterations decrease dramatically. Second, the proposed method introduces Subset simulation importance sampling (SSIS) into the active learning reliability calculation, and then a learning function suitable for SSIS is proposed. Finally, the efficiency of AK-SSIS is proved by two academic examples from the literature. The results show that AK-SSIS requires fewer calls to the performance function than AK-IS, and the failure probability obtained from AK-SSIS is very robust and accurate. Then this method is applied on a spur gear pair for tooth contact fatigue reliability analysis.

  14. Model reduction algorithms for optimal control and importance sampling of diffusions

    Science.gov (United States)

    Hartmann, Carsten; Schütte, Christof; Zhang, Wei

    2016-08-01

    We propose numerical algorithms for solving optimal control and importance sampling problems based on simplified models. The algorithms combine model reduction techniques for multiscale diffusions and stochastic optimization tools, with the aim of reducing the original, possibly high-dimensional problem to a lower dimensional representation of the dynamics, in which only a few relevant degrees of freedom are controlled or biased. Specifically, we study situations in which either a reaction coordinate onto which the dynamics can be projected is known, or situations in which the dynamics shows strongly localized behavior in the small noise regime. No explicit assumptions about small parameters or scale separation have to be made. We illustrate the approach with simple, but paradigmatic numerical examples.

  15. The jigsaw puzzle of sequence phenotype inference: Piecing together Shannon entropy, importance sampling, and Empirical Bayes.

    Science.gov (United States)

    Shreif, Zeina; Striegel, Deborah A; Periwal, Vipul

    2015-09-07

    A nucleotide sequence 35 base pairs long can take 1,180,591,620,717,411,303,424 possible values. An example of systems biology datasets, protein binding microarrays, contain activity data from about 40,000 such sequences. The discrepancy between the number of possible configurations and the available activities is enormous. Thus, albeit that systems biology datasets are large in absolute terms, they oftentimes require methods developed for rare events due to the combinatorial increase in the number of possible configurations of biological systems. A plethora of techniques for handling large datasets, such as Empirical Bayes, or rare events, such as importance sampling, have been developed in the literature, but these cannot always be simultaneously utilized. Here we introduce a principled approach to Empirical Bayes based on importance sampling, information theory, and theoretical physics in the general context of sequence phenotype model induction. We present the analytical calculations that underlie our approach. We demonstrate the computational efficiency of the approach on concrete examples, and demonstrate its efficacy by applying the theory to publicly available protein binding microarray transcription factor datasets and to data on synthetic cAMP-regulated enhancer sequences. As further demonstrations, we find transcription factor binding motifs, predict the activity of new sequences and extract the locations of transcription factor binding sites. In summary, we present a novel method that is efficient (requiring minimal computational time and reasonable amounts of memory), has high predictive power that is comparable with that of models with hundreds of parameters, and has a limited number of optimized parameters, proportional to the sequence length.

  16. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  17. Unified Importance Sampling Schemes for Efficient Simulation of Outage Capacity over Generalized Fading Channels

    KAUST Repository

    Rached, Nadhir B.

    2015-11-13

    The outage capacity (OC) is among the most important performance metrics of communication systems operating over fading channels. Of interest in the present paper is the evaluation of the OC at the output of the Equal Gain Combining (EGC) and the Maximum Ratio Combining (MRC) receivers. In this case, it can be seen that this problem turns out to be that of computing the Cumulative Distribution Function (CDF) for the sum of independent random variables. Since finding a closedform expression for the CDF of the sum distribution is out of reach for a wide class of commonly used distributions, methods based on Monte Carlo (MC) simulations take pride of price. In order to allow for the estimation of the operating range of small outage probabilities, it is of paramount importance to develop fast and efficient estimation methods as naive Monte Carlo (MC) simulations would require high computational complexity. In this line, we propose in this work two unified, yet efficient, hazard rate twisting Importance Sampling (IS) based approaches that efficiently estimate the OC of MRC or EGC diversity techniques over generalized independent fading channels. The first estimator is shown to possess the asymptotic optimality criterion and applies for arbitrary fading models, whereas the second one achieves the well-desired bounded relative error property for the majority of the well-known fading variates. Moreover, the second estimator is shown to achieve the asymptotic optimality property under the particular Log-normal environment. Some selected simulation results are finally provided in order to illustrate the substantial computational gain achieved by the proposed IS schemes over naive MC simulations.

  18. Terminological Importation for Adapting Reusable Knowledge Representation Components in the KSM Environment

    OpenAIRE

    Sierra, José Luis; Molina, Martin

    1998-01-01

    This paper describes the adaptation approach of reusable knowledge representation components used in the KSM environment for the formulation and operationalisation of structured knowledge models. Reusable knowledge representation components in KSM are called primitives of representation. A primitive of representation provides: (1) a knowledge representation formalism (2) a set of tasks that use this knowledge together with several problem-solving methods to carry out these tasks (3) a knowled...

  19. Rapid detection and differentiation of important Campylobacter spp. in poultry samples by dot blot and PCR.

    Science.gov (United States)

    Fontanot, Marco; Iacumin, Lucilla; Cecchini, Francesca; Comi, Giuseppe; Manzano, Marisa

    2014-10-01

    The detection of Campylobacter, the most commonly reported cause of foodborne gastroenteritis in the European Union, is very important for human health. The most commonly recognised risk factor for infection is the handling and/or consumption of undercooked poultry meat. The methods typically applied to evaluate the presence/absence of Campylobacter in food samples are direct plating and/or enrichment culture based on the Horizontal Method for Detection and Enumeration of Campylobacter spp. (ISO 10272-1B: 2006) and PCR. Molecular methods also allow for the detection of cells that are viable but cannot be cultivated on agar media and that decrease the time required for species identification. The current study proposes the use of two molecular methods for species identification: dot blot and PCR. The dot blot method had a sensitivity of 25 ng for detection of DNA extracted from a pure culture using a digoxigenin-labelled probe for hybridisation; the target DNA was extracted from the enrichment broth at 24 h. PCR was performed using a pair of sensitive and specific primers for the detection of Campylobacter jejuni and Campylobacter coli after 24 h of enrichment in Preston broth. The initial samples were contaminated by 5 × 10 C. jejuni cells/g and 1.5 × 10(2)C. coli cells/g, thus the number of cells present in the enrichment broth at 0 h was 1 or 3 cell/g, respectively.

  20. Component-adaptive up-sampling for inter layer interpolation in scalable video coding

    Institute of Scientific and Technical Information of China (English)

    WANG Zhang; ZHANG JiXian; LI HaiTao

    2009-01-01

    Scalable video coding (SVC) is a newly emerging standard to be finalized as an extension of H.264/AVC. The most attractive characters in SVC are the inter layer prediction techniques, such as Intra_BL mode. But in current SVC scheme, a uniform up-sampling filter (UUSF) is employed to magnify all components of an image, which will be very inefficient and result in a lot of redundant computational complexity. To overcome this, we propose an efficient component-adaptive up-sampling filter (CAUSF) for inter layer interpolation. In CAUSF, one character of human vision system is considered, and different up-sampling filters are assigned to different components. In particular, the six-tap FIR filter used in UUSF is kept and assigned for luminance component. But for chrominance components, a new four-tap FIR filter is used. Experimental results show that CAUSF maintains the performances of coded bit-rate and PSNR-Y without any noticeable loss, and provides significant reduction in computational complexity.

  1. PARALLEL ADAPTIVE MULTILEVEL SAMPLING ALGORITHMS FOR THE BAYESIAN ANALYSIS OF MATHEMATICAL MODELS

    KAUST Repository

    Prudencio, Ernesto

    2012-01-01

    In recent years, Bayesian model updating techniques based on measured data have been applied to many engineering and applied science problems. At the same time, parallel computational platforms are becoming increasingly more powerful and are being used more frequently by the engineering and scientific communities. Bayesian techniques usually require the evaluation of multi-dimensional integrals related to the posterior probability density function (PDF) of uncertain model parameters. The fact that such integrals cannot be computed analytically motivates the research of stochastic simulation methods for sampling posterior PDFs. One such algorithm is the adaptive multilevel stochastic simulation algorithm (AMSSA). In this paper we discuss the parallelization of AMSSA, formulating the necessary load balancing step as a binary integer programming problem. We present a variety of results showing the effectiveness of load balancing on the overall performance of AMSSA in a parallel computational environment.

  2. Accelerating the convergence of replica exchange simulations using Gibbs sampling and adaptive temperature sets

    CERN Document Server

    Vogel, Thomas

    2015-01-01

    We recently introduced a novel replica-exchange scheme in which an individual replica can sample from states encountered by other replicas at any previous time by way of a global configuration database, enabling the fast propagation of relevant states through the whole ensemble of replicas. This mechanism depends on the knowledge of global thermodynamic functions which are measured during the simulation and not coupled to the heat bath temperatures driving the individual simulations. Therefore, this setup also allows for a continuous adaptation of the temperature set. In this paper, we will review the new scheme and demonstrate its capability. The method is particularly useful for the fast and reliable estimation of the microcanonical temperature T(U) or, equivalently, of the density of states g(U) over a wide range of energies.

  3. Real-time nutrient monitoring in rivers: adaptive sampling strategies, technological challenges and future directions

    Science.gov (United States)

    Blaen, Phillip; Khamis, Kieran; Lloyd, Charlotte; Bradley, Chris

    2016-04-01

    Excessive nutrient concentrations in river waters threaten aquatic ecosystem functioning and can pose substantial risks to human health. Robust monitoring strategies are therefore required to generate reliable estimates of river nutrient loads and to improve understanding of the catchment processes that drive spatiotemporal patterns in nutrient fluxes. Furthermore, these data are vital for prediction of future trends under changing environmental conditions and thus the development of appropriate mitigation measures. In recent years, technological developments have led to an increase in the use of continuous in-situ nutrient analysers, which enable measurements at far higher temporal resolutions than can be achieved with discrete sampling and subsequent laboratory analysis. However, such instruments can be costly to run and difficult to maintain (e.g. due to high power consumption and memory requirements), leading to trade-offs between temporal and spatial monitoring resolutions. Here, we highlight how adaptive monitoring strategies, comprising a mixture of temporal sample frequencies controlled by one or more 'trigger variables' (e.g. river stage, turbidity, or nutrient concentration), can advance our understanding of catchment nutrient dynamics while simultaneously overcoming many of the practical and economic challenges encountered in typical in-situ river nutrient monitoring applications. We present examples of short-term variability in river nutrient dynamics, driven by complex catchment behaviour, which support our case for the development of monitoring systems that can adapt in real-time to rapid environmental changes. In addition, we discuss the advantages and disadvantages of current nutrient monitoring techniques, and suggest new research directions based on emerging technologies and highlight how these might improve: 1) monitoring strategies, and 2) understanding of linkages between catchment processes and river nutrient fluxes.

  4. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

    Directory of Open Access Journals (Sweden)

    Bruno Srbinovski

    2016-03-01

    Full Text Available Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind. Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources and power hungry sensors (ultrasonic wind sensor and gas sensors. The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

  5. [Attaching importance to study on acute health risk assessment and adaptation of air pollution and climate change].

    Science.gov (United States)

    Shi, X M

    2017-03-10

    Air pollution and climate change have become key environmental and public health problems around the world, which poses serious threat to human health. How to assess and mitigate the health risks and increase the adaptation of the public have become an urgent topic of research in this area. The six papers in this issue will provide important and rich information on design, analysis method, indicator selection and setting about acute health risk assessment and adaptation study of air pollution and climate change in China, reflecting the advanced conceptions of multi-center and area-specific study and multi-pollutant causing acute effect study. However, the number and type of the cities included in these studies were still limited. In future, researchers should further expand detailed multi-center and multi-area study coverage, conduct area specific predicting and early warning study and strengthen adaptation study.

  6. Estimation of failure probabilities of linear dynamic systems by importance sampling

    Indian Academy of Sciences (India)

    Anna Ivanova Olsen; Arvid Naess

    2006-08-01

    An iterative method for estimating the failure probability for certain time-variant reliability problems has been developed. In the paper, the focus is on the displacement response of a linear oscillator driven by white noise. Failure is then assumed to occur when the displacement response exceeds a critical threshold. The iteration procedure is a two-step method. On the first iteration, a simple control function promoting failure is constructed using the design point weighting principle. After time discretization, two points are chosen to construct a compound deterministic control function. It is based on the time point when the first maximum of the homogenous solution has occurred and on the point at the end of the considered time interval. An importance sampling technique is used in order to estimate the failure probability functional on a set of initial values of state space variables and time. On the second iteration, the concept of optimal control function can be implemented to construct a Markov control which allows much better accuracy in the failure probability estimate than the simple control function. On both iterations, the concept of changing the probability measure by the Girsanov transformation is utilized. As a result the CPU time is substantially reduced compared with the crude Monte Carlo procedure.

  7. Efficient estimation of abundance for patchily distributed populations via two-phase, adaptive sampling.

    Science.gov (United States)

    Conroy, M.J.; Runge, J.P.; Barker, R.J.; Schofield, M.R.; Fonnesbeck, C.J.

    2008-01-01

    Many organisms are patchily distributed, with some patches occupied at high density, others at lower densities, and others not occupied. Estimation of overall abundance can be difficult and is inefficient via intensive approaches such as capture-mark-recapture (CMR) or distance sampling. We propose a two-phase sampling scheme and model in a Bayesian framework to estimate abundance for patchily distributed populations. In the first phase, occupancy is estimated by binomial detection samples taken on all selected sites, where selection may be of all sites available, or a random sample of sites. Detection can be by visual surveys, detection of sign, physical captures, or other approach. At the second phase, if a detection threshold is achieved, CMR or other intensive sampling is conducted via standard procedures (grids or webs) to estimate abundance. Detection and CMR data are then used in a joint likelihood to model probability of detection in the occupancy sample via an abundance-detection model. CMR modeling is used to estimate abundance for the abundance-detection relationship, which in turn is used to predict abundance at the remaining sites, where only detection data are collected. We present a full Bayesian modeling treatment of this problem, in which posterior inference on abundance and other parameters (detection, capture probability) is obtained under a variety of assumptions about spatial and individual sources of heterogeneity. We apply the approach to abundance estimation for two species of voles (Microtus spp.) in Montana, USA. We also use a simulation study to evaluate the frequentist properties of our procedure given known patterns in abundance and detection among sites as well as design criteria. For most population characteristics and designs considered, bias and mean-square error (MSE) were low, and coverage of true parameter values by Bayesian credibility intervals was near nominal. Our two-phase, adaptive approach allows efficient estimation of

  8. Insights on antioxidant assays for biological samples based on the reduction of copper complexes-the importance of analytical conditions.

    Science.gov (United States)

    Marques, Sara S; Magalhães, Luís M; Tóth, Ildikó V; Segundo, Marcela A

    2014-06-25

    Total antioxidant capacity assays are recognized as instrumental to establish antioxidant status of biological samples, however the varying experimental conditions result in conclusions that may not be transposable to other settings. After selection of the complexing agent, reagent addition order, buffer type and concentration, copper reducing assays were adapted to a high-throughput scheme and validated using model biological antioxidant compounds of ascorbic acid, Trolox (a soluble analogue of vitamin E), uric acid and glutathione. A critical comparison was made based on real samples including NIST-909c human serum certified sample, and five study samples. The validated method provided linear range up to 100 µM Trolox, (limit of detection 2.3 µM; limit of quantification 7.7 µM) with recovery results above 85% and precision <5%. The validated developed method with an increased sensitivity is a sound choice for assessment of TAC in serum samples.

  9. Insights on Antioxidant Assays for Biological Samples Based on the Reduction of Copper Complexes—The Importance of Analytical Conditions

    Directory of Open Access Journals (Sweden)

    Sara S. Marques

    2014-06-01

    Full Text Available Total antioxidant capacity assays are recognized as instrumental to establish antioxidant status of biological samples, however the varying experimental conditions result in conclusions that may not be transposable to other settings. After selection of the complexing agent, reagent addition order, buffer type and concentration, copper reducing assays were adapted to a high-throughput scheme and validated using model biological antioxidant compounds of ascorbic acid, Trolox (a soluble analogue of vitamin E, uric acid and glutathione. A critical comparison was made based on real samples including NIST-909c human serum certified sample, and five study samples. The validated method provided linear range up to 100 µM Trolox, (limit of detection 2.3 µM; limit of quantification 7.7 µM with recovery results above 85% and precision <5%. The validated developed method with an increased sensitivity is a sound choice for assessment of TAC in serum samples.

  10. Flexible binding simulation by a novel and improved version of virtual-system coupled adaptive umbrella sampling

    Science.gov (United States)

    Dasgupta, Bhaskar; Nakamura, Haruki; Higo, Junichi

    2016-10-01

    Virtual-system coupled adaptive umbrella sampling (VAUS) enhances sampling along a reaction coordinate by using a virtual degree of freedom. However, VAUS and regular adaptive umbrella sampling (AUS) methods are yet computationally expensive. To decrease the computational burden further, improvements of VAUS for all-atom explicit solvent simulation are presented here. The improvements include probability distribution calculation by a Markov approximation; parameterization of biasing forces by iterative polynomial fitting; and force scaling. These when applied to study Ala-pentapeptide dimerization in explicit solvent showed advantage over regular AUS. By using improved VAUS larger biological systems are amenable.

  11. Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers

    Science.gov (United States)

    Lu, George J.; Opella, Stanley J.

    2013-01-01

    One of the main applications of solid-state NMR is to study the structure and dynamics of biopolymers, such as membrane proteins, under physiological conditions where the polypeptides undergo global motions as they do in biological membranes. The effects of NMR radiofrequency irradiations on nuclear spins are strongly influenced by these motions. For example, we previously showed that the MSHOT-Pi4 pulse sequence yields spectra with resonance line widths about half of those observed using the conventional pulse sequence when applied to membrane proteins undergoing rapid uniaxial rotational diffusion in phospholipid bilayers. In contrast, the line widths were not changed in microcrystalline samples where the molecules did not undergo global motions. Here, we demonstrate experimentally and describe analytically how some Hamiltonian terms are susceptible to sample motions, and it is their removal through the critical π/2 Z-rotational symmetry that confers the “motion adapted” property to the MSHOT-Pi4 pulse sequence. This leads to the design of separated local field pulse sequence “Motion-adapted SAMPI4” and is generalized to an approach for the design of decoupling sequences whose performance is superior in the presence of molecular motions. It works by cancelling the spin interaction by explicitly averaging the reduced Wigner matrix to zero, rather than utilizing the 2π nutation to average spin interactions. This approach is applicable to both stationary and magic angle spinning solid-state NMR experiments. PMID:24006989

  12. Adaptive Sampling-Based Information Collection for Wireless Body Area Networks

    OpenAIRE

    Xiaobin Xu; Fang Zhao; Wendong Wang; Hui Tian

    2016-01-01

    To collect important health information, WBAN applications typically sense data at a high frequency. However, limited by the quality of wireless link, the uploading of sensed data has an upper frequency. To reduce upload frequency, most of the existing WBAN data collection approaches collect data with a tolerable error. These approaches can guarantee precision of the collected data, but they are not able to ensure that the upload frequency is within the upper frequency. Some traditional sampl...

  13. Important aspects of residue sampling in drilling dikes; Aspectos importantes para a amostragem de residuos em diques de perfuracao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gilvan Ferreira da [PETROBRAS, Rio de Janeiro (Brazil). Centro de Pesquisas. Div. de Explotacao

    1989-12-31

    This paper describes the importance of sampling in the evaluation of physical and chemical properties of residues found in drilling dikes, considering the later selection of treatment methods or discard of these residues. We present the fundamental concepts of applied statistics, which are essential to the elaboration of sampling plans, with views of obtaining exact and precise results. Other types of samples are also presented, as well as sampling equipment and methods for storage and preservation of the samples. As a conclusion, we the example of the implementation of a sampling plan. (author) 3 refs., 9 figs., 3 tabs.

  14. Bandpass Sampling--An Opportunity to Stress the Importance of In-Depth Understanding

    Science.gov (United States)

    Stern, Harold P. E.

    2010-01-01

    Many bandpass signals can be sampled at rates lower than the Nyquist rate, allowing significant practical advantages. Illustrating this phenomenon after discussing (and proving) Shannon's sampling theorem provides a valuable opportunity for an instructor to reinforce the principle that innovation is possible when students strive to have a complete…

  15. Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations.

    Directory of Open Access Journals (Sweden)

    Oscar Vedder

    2013-07-01

    Full Text Available Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations.

  16. Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations.

    Science.gov (United States)

    Vedder, Oscar; Bouwhuis, Sandra; Sheldon, Ben C

    2013-07-01

    Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major) breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations.

  17. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadingson Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    This paper discusses the influence of wave load sampling frequency on calculated sliding distance in an overall stability analysis of a monolithic caisson. It is demonstrated by a specific example of caisson design that for this kind of analyses the sampling frequency in a small scale model could...... be as low as 100 Hz in model scale. However, for design of structure elements like the wave wall on the top of a caisson the wave load sampling frequency must be much higher, in the order of 1000 Hz in the model. Elastic-plastic deformations of foundation and structure were not included in the analysis....

  18. Blood Volume: Importance and Adaptations to Exercise Training, Environmental Stresses and Trauma/Sickness

    Science.gov (United States)

    Sawka, Michael N.; Convertino, Victor A.; Eichner, E. Randy; Schnieder, Suzanne M.; Young, Andrew J.

    2000-01-01

    This paper reviews the influence of several perturbations (physical exercise, heat stress, terrestrial altitude, microgravity, and trauma/sickness) on adaptations of blood volume (BV), erythrocyte volume (EV), and plasma volume (PV). Exercise training can induced BV expansion; PV expansion usually occurs immediately, but EV expansion takes weeks. EV and PV expansion contribute to aerobic power improvements associated with exercise training. Repeated heat exposure induces PV expansion but does not alter EV. PV expansion does not improve thermoregulation, but EV expansion improves thermoregulation during exercise in the heat. Dehydration decreases PV (and increases plasma tonicity) which elevates heat strain and reduces exercise performance. High altitude exposure causes rapid (hours) plasma loss. During initial weeks at altitude, EV is unaffected, but a gradual expansion occurs with extended acclimatization. BV adjustments contribute, but are not key, to altitude acclimatization. Microgravity decreases PV and EV which contribute to orthostatic intolerance and decreased exercise capacity in astronauts. PV decreases may result from lower set points for total body water and central venous pressure, which EV decrease bay result form increased erythrocyte destruction. Trauma, renal disease, and chronic diseases cause anemia from hemorrhage and immune activation, which suppressions erythropoiesis. The re-establishment of EV is associated with healing, improved life quality, and exercise capabilities for these injured/sick persons.

  19. What do we call Adaptive Management? A general characterization from a global sample

    Directory of Open Access Journals (Sweden)

    T. Espigares

    2008-03-01

    Full Text Available This study presents a characterisation of the implementation of Adaptive Management (AM from the analysis of 35 projects around the world. Our results reveal that AM projects are usually aimed at ecosystem management, conservation and restoration. Also, they mainly act upon forest or epicontinental water ecosystems and their goal is generally species exploitation and in most cases these projects act at a local scale. From a methodological point of view, most AM cases use an active approach and monitoring programs and were at the phase of problem identification. We found differences in the implementation of AM between developed and developing countries that were present in our samples in the following way: AM projects in developed countries were typically carried out by state agencies, and focused on solving problems concerning epicontinental waters and the public use of ecosystems. They had the support of national funds and used modelling techniques. In contrast, the AM projects from developing countries were mainly aimed at the conservation of natural protected areas and at the mitigation of environmental impacts derived from mining activities. The financial support of these projects was frequently provided by international organizations, and the use of modelling techniques was uncommon. For a better exploitation of all the possibilities of AM, we suggest the use of criteria to be customized to the specific needs of the socio-economic reality of every country and to monitor the results at a global scale to continuously improve this practice.

  20. French Adaptation of the Narcissistic Personality Inventory in a Belgian French-Speaking Sample.

    Science.gov (United States)

    Braun, Stéphanie; Kempenaers, Chantal; Linkowski, Paul; Loas, Gwenolé

    2016-01-01

    The Narcissistic Personality Inventory (NPI) is the most widely used self-report scale to assess the construct of narcissism, especially in its grandiosity expression. Over the years, several factor models have been proposed in order to improve the understanding of the multidimensional aspect of this construct. The available data are heterogeneous, suggesting one to at least seven factors. In this study, we propose a French adaptation of the NPI submitted to a sample of Belgian French-speaking students (n = 942). We performed a principal component analysis on a tetrachoric correlation matrix to explore its factor structure. Unlike previous studies, our study shows that a first factor explains the largest part of the variance. Internal consistency is excellent and we reproduced the sex differences reported when using the original scale. Correlations with social desirability are taken into account in the interpretation of our results. Altogether, the results of this study support a unidimensional structure for the NPI using the total score as a self-report measure of the Narcissistic Personality Disorder in its grandiose form. Future studies including confirmatory factor analysis and gender invariance measurement are also discussed.

  1. Interexaminer agreement dental caries epidemiological surveys: the importance of disease prevalence in the sample

    Directory of Open Access Journals (Sweden)

    Aline Sampieri Tonello

    Full Text Available Abstract: Objective: To identify desirable characteristics, including different sample sizes and dental caries prevalences, in virtual samples that allow, at the same time, higher values of general agreement percentage (GPA and Kappa coefficient (κ, under a low confidence interval (CI, in reproducibility studies. Method: A total of 384 statistical simulations of inter-examiner calibration, varying sample size (12, 15, 20, 60, 200 and 500 individuals, caries prevalence (30, 50, 60 and 90% and percentages of positive (PA and negative (NA agreement (30, 50, 60 and 90% were undertaken. GPA and κ were used to measure reproducibility and define deviation between them. Results: The sample of 60 individuals, under caries prevalence of 50%, PA and NA of 90%, presented a GPA and Kappa values of 90 and 80%, respectively, a relative small confidence interval (95%CI 0.65 - 0.95 and a GPA/Kappa deviation of 10.00. Conclusion: A virtual sample of 60 individuals, under caries prevalence of 50%, seems feasible to produce a satisfactory interexaminer agreement at epidemiological conditions. However, epidemiological studies to corroborate or refute this assertion are necessary.

  2. Monte Carlo sampling and multivariate adaptive regression splines as tools for QSAR modelling of HIV-1 reverse transcriptase inhibitors.

    Science.gov (United States)

    Alamdari, R F; Mani-Varnosfaderani, A; Asadollahi-Baboli, M; Khalafi-Nezhad, A

    2012-10-01

    The present work focuses on the development of an interpretable quantitative structure-activity relationship (QSAR) model for predicting the anti-HIV activities of 67 thiazolylthiourea derivatives. This set of molecules has been proposed as potent HIV-1 reverse transcriptase inhibitors (RT-INs). The molecules were encoded to a diverse set of molecular descriptors, spanning different physical and chemical properties. Monte Carlo (MC) sampling and multivariate adaptive regression spline (MARS) techniques were used to select the most important descriptors and to predict the activity of the molecules. The most important descriptor was found to be the aspherisity index. The analysis of variance (ANOVA) and interpretable spline equations showed that the geometrical shape of the molecules has considerable effect on their activities. It seems that the linear molecules are more active than symmetric top compounds. The final MARS model derived displayed a good predictive ability judging from the determination coefficient corresponding to the leave multiple out (LMO) cross-validation technique, i.e. r (2 )= 0.828 (M = 12) and r (2 )= 0.813 (M = 20). The results of this work showed that the developed spline model is robust, has a good predictive power, and can then be used as a reliable tool for designing novel HIV-1 RT-INs.

  3. Blood Volume: Importance and Adaptations to Exercise Training, Environmental Stresses and Trauma Sickness

    Science.gov (United States)

    2000-02-01

    the elevation of Hb concentration (from plasma loss) is the most important factor contributing to the performance improve- ment by facilitating O2...A., P. J. BROCK, L. C. KEIL, E. M. BERNAUER, and J. E. GREENLEAF. Exercise training-induced hypervolemia: role of plasma albumin, renin , and...mechanism of hypervol- emia. J. Appl. Physiol. 48:657–664, 1980. 27. CONVERTINO, V. A., L. C. KEIL, and J. E. GREENLEAF. Plasma volume, renin , and

  4. A Feedfordward Adaptive Controller to Reduce the Imaging Time of Large-Sized Biological Samples with a SPM-Based Multiprobe Station

    Directory of Open Access Journals (Sweden)

    Manel Puig-Vidal

    2012-01-01

    Full Text Available The time required to image large samples is an important limiting factor in SPM-based systems. In multiprobe setups, especially when working with biological samples, this drawback can make impossible to conduct certain experiments. In this work, we present a feedfordward controller based on bang-bang and adaptive controls. The controls are based in the difference between the maximum speeds that can be used for imaging depending on the flatness of the sample zone. Topographic images of Escherichia coli bacteria samples were acquired using the implemented controllers. Results show that to go faster in the flat zones, rather than using a constant scanning speed for the whole image, speeds up the imaging process of large samples by up to a 4x factor.

  5. A whole-path importance-sampling scheme for Feynman path integral calculations of absolute partition functions and free energies.

    Science.gov (United States)

    Mielke, Steven L; Truhlar, Donald G

    2016-01-21

    Using Feynman path integrals, a molecular partition function can be written as a double integral with the inner integral involving all closed paths centered at a given molecular configuration, and the outer integral involving all possible molecular configurations. In previous work employing Monte Carlo methods to evaluate such partition functions, we presented schemes for importance sampling and stratification in the molecular configurations that constitute the path centroids, but we relied on free-particle paths for sampling the path integrals. At low temperatures, the path sampling is expensive because the paths can travel far from the centroid configuration. We now present a scheme for importance sampling of whole Feynman paths based on harmonic information from an instantaneous normal mode calculation at the centroid configuration, which we refer to as harmonically guided whole-path importance sampling (WPIS). We obtain paths conforming to our chosen importance function by rejection sampling from a distribution of free-particle paths. Sample calculations on CH4 demonstrate that at a temperature of 200 K, about 99.9% of the free-particle paths can be rejected without integration, and at 300 K, about 98% can be rejected. We also show that it is typically possible to reduce the overhead associated with the WPIS scheme by sampling the paths using a significantly lower-order path discretization than that which is needed to converge the partition function.

  6. Intraspecific shape variation in horseshoe crabs: the importance of sexual and natural selection for local adaptation

    DEFF Research Database (Denmark)

    Faurby, Søren; Nielsen, Kasper Sauer Kollerup; Bussarawit, Somchai

    2011-01-01

    A morphometric analysis of the body shape of three species of horseshoe crabs was undertaken in order to infer the importance of natural and sexual selection. It was expected that natural selection would be most intense, leading to highest regional differentiation, in the American species Limulus...... from nine populations, representing three species, were analyzed using a digitizer to position sixty morphometric landmarks in a three-dimensional space. Discriminant analysis revealed strong regional structuring within a species, which suggests strong philopatry, and showed the existence...

  7. The two-component system CBO2306/CBO2307 is important for cold adaptation of Clostridium botulinum ATCC 3502.

    Science.gov (United States)

    Derman, Yağmur; Isokallio, Marita; Lindström, Miia; Korkeala, Hannu

    2013-10-01

    Clostridium botulinum is a notorious foodborne pathogen. Its ability to adapt to and grow at low temperatures is of interest for food safety. Two-component systems (TCSs) have been reported to be involved in cold-shock and growth at low temperatures. Here we show the importance of TCS CBO2306/CBO2307 in the cold-shock response of C. botulinum ATCC 3502. The relative expression levels of the cbo2306 and cbo2307 were up to 4.4-fold induced in the cold-shocked cultures but negatively regulated in the late-log and stationary growth phase in relation to early logarithmic growth phase in non-shocked cultures. Importance of the CBO2306/CBO2307 in the cold stress was further demonstrated by impaired growth of insertional cbo2306 or cbo2307 knockout mutants in relation to the wild-type strain ATCC 3502. The results suggest that the TCS CBO2306/CBO2307 is important for cold-shock response and adaptation of C. botulinum ATCC 3502 to low temperature.

  8. Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality

    DEFF Research Database (Denmark)

    Liu, Na; Nielsen, Henrik Kofoed; Jørgensen, Uffe

    2015-01-01

    Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow...... clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn......) in each section were determined. The results showed large spatial variation in the distribution of most elements along the length of the willow shoots. Concentrations of elements in 2-year old shoots of the willow clone Tordis were fairly stable within the range of 100–285 cm above ground and resembled...

  9. Importance of sample pH on recovery of mutagenicity from drinking water by XAD resins

    Energy Technology Data Exchange (ETDEWEB)

    Ringhand, H.P.; Meier, J.R.; Kopfler, F.C.; Schenck, K.M.; Kaylor, W.H.; Mitchell, D.E.

    1987-04-01

    Sample pH and the presence of a chlorine residual were evaluated for their effects of the recovery of mutagenicity in drinking water following concentration by XAD resins. The levels of mutagenicity in the pH 2 concentrates were 7-8-fold higher than those of the pH 8 concentrates, suggesting that acidic compounds accounted for the majority of the mutagenicity. The presence of a chlorine residual had little effect on the levels of mutagenicity at either pH. Comparisons of the mutagenic activity for the pH 2 resin concentrates vs. pH 8 concentrates prepared by lyophilization further indicated that the acidic mutagens were products of disinfection with chlorine and not artifacts of the sample acidification step in the concentration procedure. 27 references, 6 figures, 1 table.

  10. Importance of sampling design and analysis in animal population studies: a comment on Sergio et al

    Science.gov (United States)

    Kery, M.; Royle, J. Andrew; Schmid, Hans

    2008-01-01

    1. The use of predators as indicators and umbrellas in conservation has been criticized. In the Trentino region, Sergio et al. (2006; hereafter SEA) counted almost twice as many bird species in quadrats located in raptor territories than in controls. However, SEA detected astonishingly few species. We used contemporary Swiss Breeding Bird Survey data from an adjacent region and a novel statistical model that corrects for overlooked species to estimate the expected number of bird species per quadrat in that region. 2. There are two anomalies in SEA which render their results ambiguous. First, SEA detected on average only 6.8 species, whereas a value of 32 might be expected. Hence, they probably overlooked almost 80% of all species. Secondly, the precision of their mean species counts was greater in two-thirds of cases than in the unlikely case that all quadrats harboured exactly the same number of equally detectable species. This suggests that they detected consistently only a biased, unrepresentative subset of species. 3. Conceptually, expected species counts are the product of true species number and species detectability p. Plenty of factors may affect p, including date, hour, observer, previous knowledge of a site and mobbing behaviour of passerines in the presence of predators. Such differences in p between raptor and control quadrats could have easily created the observed effects. Without a method that corrects for such biases, or without quantitative evidence that species detectability was indeed similar between raptor and control quadrats, the meaning of SEA's counts is hard to evaluate. Therefore, the evidence presented by SEA in favour of raptors as indicator species for enhanced levels of biodiversity remains inconclusive. 4. Synthesis and application. Ecologists should pay greater attention to sampling design and analysis in animal population estimation. Species richness estimation means sampling a community. Samples should be representative for the

  11. The soft palate is an important site of adaptation for transmissible influenza viruses.

    Science.gov (United States)

    Lakdawala, Seema S; Jayaraman, Akila; Halpin, Rebecca A; Lamirande, Elaine W; Shih, Angela R; Stockwell, Timothy B; Lin, Xudong; Simenauer, Ari; Hanson, Christopher T; Vogel, Leatrice; Paskel, Myeisha; Minai, Mahnaz; Moore, Ian; Orandle, Marlene; Das, Suman R; Wentworth, David E; Sasisekharan, Ram; Subbarao, Kanta

    2015-10-01

    Influenza A viruses pose a major public health threat by causing seasonal epidemics and sporadic pandemics. Their epidemiological success relies on airborne transmission from person to person; however, the viral properties governing airborne transmission of influenza A viruses are complex. Influenza A virus infection is mediated via binding of the viral haemagglutinin (HA) to terminally attached α2,3 or α2,6 sialic acids on cell surface glycoproteins. Human influenza A viruses preferentially bind α2,6-linked sialic acids whereas avian influenza A viruses bind α2,3-linked sialic acids on complex glycans on airway epithelial cells. Historically, influenza A viruses with preferential association with α2,3-linked sialic acids have not been transmitted efficiently by the airborne route in ferrets. Here we observe efficient airborne transmission of a 2009 pandemic H1N1 (H1N1pdm) virus (A/California/07/2009) engineered to preferentially bind α2,3-linked sialic acids. Airborne transmission was associated with rapid selection of virus with a change at a single HA site that conferred binding to long-chain α2,6-linked sialic acids, without loss of α2,3-linked sialic acid binding. The transmissible virus emerged in experimentally infected ferrets within 24 hours after infection and was remarkably enriched in the soft palate, where long-chain α2,6-linked sialic acids predominate on the nasopharyngeal surface. Notably, presence of long-chain α2,6-linked sialic acids is conserved in ferret, pig and human soft palate. Using a loss-of-function approach with this one virus, we demonstrate that the ferret soft palate, a tissue not normally sampled in animal models of influenza, rapidly selects for transmissible influenza A viruses with human receptor (α2,6-linked sialic acids) preference.

  12. Adaptive geostatistical sampling enables efficient identification of malaria hotspots in repeated cross-sectional surveys in rural Malawi

    Science.gov (United States)

    Chipeta, Michael G.; McCann, Robert S.; Phiri, Kamija S.; van Vugt, Michèle; Takken, Willem; Diggle, Peter; Terlouw, Anja D.

    2017-01-01

    Introduction In the context of malaria elimination, interventions will need to target high burden areas to further reduce transmission. Current tools to monitor and report disease burden lack the capacity to continuously detect fine-scale spatial and temporal variations of disease distribution exhibited by malaria. These tools use random sampling techniques that are inefficient for capturing underlying heterogeneity while health facility data in resource-limited settings are inaccurate. Continuous community surveys of malaria burden provide real-time results of local spatio-temporal variation. Adaptive geostatistical design (AGD) improves prediction of outcome of interest compared to current random sampling techniques. We present findings of continuous malaria prevalence surveys using an adaptive sampling design. Methods We conducted repeated cross sectional surveys guided by an adaptive sampling design to monitor the prevalence of malaria parasitaemia and anaemia in children below five years old in the communities living around Majete Wildlife Reserve in Chikwawa district, Southern Malawi. AGD sampling uses previously collected data to sample new locations of high prediction variance or, where prediction exceeds a set threshold. We fitted a geostatistical model to predict malaria prevalence in the area. Findings We conducted five rounds of sampling, and tested 876 children aged 6–59 months from 1377 households over a 12-month period. Malaria prevalence prediction maps showed spatial heterogeneity and presence of hotspots—where predicted malaria prevalence was above 30%; predictors of malaria included age, socio-economic status and ownership of insecticide-treated mosquito nets. Conclusions Continuous malaria prevalence surveys using adaptive sampling increased malaria prevalence prediction accuracy. Results from the surveys were readily available after data collection. The tool can assist local managers to target malaria control interventions in areas with the

  13. Indigenizing or Adapting? Importing Buddhism into a Settler-colonial Society

    Directory of Open Access Journals (Sweden)

    Sally McAra

    2015-02-01

    Full Text Available In this paper I problematize the phrase "indigenization of Buddhism" (Spuler 2003, cf. Baumann 1997 through an investigation of a Buddhist project in a settler-colonial society. An international organization called the Foundation for the Preservation of the Mahayana Tradition (FPMT is constructing a forty-five-meter high stupa in rural Australia with the intention "to provide a refuge of peace and serenity for all." In 2003, a woman of Aboriginal descent met with the stupa developers to express her concern about the project. While her complaint does not represent local Aboriginal views about the stupa (other Aboriginal groups expressed support for it, it illustrates how in settler-colonial societies, Buddhist cultural imports that mark the land can have unexpected implications for indigenous people. This paper offers a glimpse of the multi-layered power relations that form the often invisible backdrop to the establishment of Buddhism in settler-colonial societies and suggests that we need to find terms other than "indigenization" when analyzing this.

  14. Eco-Physiologic studies an important tool for the adaptation of forestry to global changes.

    Directory of Open Access Journals (Sweden)

    HASAN CANI

    2014-06-01

    Full Text Available Forests are the dominant land use in Albania, occupying almost 1.5 million hectares [11], but c.a. 70% of the forest area belong coppices and shrub forests, as the results of unsustainable practices, intensive cutting and overgrazing. Forest ecosystems serve many ecological roles, including regulation of the planet's carbon and water cycles. Forests are also important components of economic systems. Research in the Forest Ecophysiology studies on the Faculty of Forestry Sciences is intended to produce biological knowledge that can be used to better manage forest resources for sustainable production of economic and non-economic values and aims to improve the understanding of past and current dynamics of Mediterranean and temperate forests. The overarching goal is to quantify the influence of genetics, climate, environmental stresses, and forest management inputs on forest productivity and carbon sequestration, and to understand the physiological mechanisms underlying these responses.Process-based models open the way to useful predictions of the future growth rate of forests and provide a means of assessing the probable effects of variations in climate and management on forest productivity. As such they have the potential to overcome the limitations of conventional forest growth and yield models. This paper discusses the basic physiological processes that determine the growth of plants, the way they are affected by environmental factors and how we can improve processes that are well-understood such as growth from leaf to stand level and productivity. The study trays to show a clear relationship between temperature and water relations and other factors affecting forest plant germination and growth that are often looked at separately. This integrated approach will provide the most comprehensive source for process-based modelling, which is valuable to ecologists, plant physiologists, forest planners and environmental scientists [10]. Actually the

  15. De novo mutations from sporadic schizophrenia cases highlight important signaling genes in an independent sample.

    Science.gov (United States)

    Kranz, Thorsten M; Harroch, Sheila; Manor, Orly; Lichtenberg, Pesach; Friedlander, Yechiel; Seandel, Marco; Harkavy-Friedman, Jill; Walsh-Messinger, Julie; Dolgalev, Igor; Heguy, Adriana; Chao, Moses V; Malaspina, Dolores

    2015-08-01

    Schizophrenia is a debilitating syndrome with high heritability. Genomic studies reveal more than a hundred genetic variants, largely nonspecific and of small effect size, and not accounting for its high heritability. De novo mutations are one mechanism whereby disease related alleles may be introduced into the population, although these have not been leveraged to explore the disease in general samples. This paper describes a framework to find high impact genes for schizophrenia. This study consists of two different datasets. First, whole exome sequencing was conducted to identify disruptive de novo mutations in 14 complete parent-offspring trios with sporadic schizophrenia from Jerusalem, which identified 5 sporadic cases with de novo gene mutations in 5 different genes (PTPRG, TGM5, SLC39A13, BTK, CDKN3). Next, targeted exome capture of these genes was conducted in 48 well-characterized, unrelated, ethnically diverse schizophrenia cases, recruited and characterized by the same research team in New York (NY sample), which demonstrated extremely rare and potentially damaging variants in three of the five genes (MAFgene they carried. Functional de novo mutations in protein-interaction domains in sporadic schizophrenia can illuminate risk genes that increase the propensity to develop schizophrenia across ethnicities.

  16. Numerical Study of φ4 Model by Potential Importance Sampling Method

    Institute of Scientific and Technical Information of China (English)

    YUAN Qing-Xin; DING Guo-Hui

    2006-01-01

    We investigate the phenomena of spontaneous symmetry breaking for φ4 modelon a square lattice in the parameter space by using the potential importance samplingmethod, which was proposed by Milchev, Heermann, and Binder [J. Stat. Phys. 44 (1986) 749]. The critical values of the parameters allow us to determine the phase diagram of the model. At the same time, some relevant quantities such as susceptibility and specific heat are also obtained.

  17. A comparison of adaptive sampling designs and binary spatial models: A simulation study using a census of Bromus inermis

    Science.gov (United States)

    Irvine, Kathryn M.; Thornton, Jamie; Backus, Vickie M.; Hohmann, Matthew G.; Lehnhoff, Erik A.; Maxwell, Bruce D.; Michels, Kurt; Rew, Lisa

    2013-01-01

    Commonly in environmental and ecological studies, species distribution data are recorded as presence or absence throughout a spatial domain of interest. Field based studies typically collect observations by sampling a subset of the spatial domain. We consider the effects of six different adaptive and two non-adaptive sampling designs and choice of three binary models on both predictions to unsampled locations and parameter estimation of the regression coefficients (species–environment relationships). Our simulation study is unique compared to others to date in that we virtually sample a true known spatial distribution of a nonindigenous plant species, Bromus inermis. The census of B. inermis provides a good example of a species distribution that is both sparsely (1.9 % prevalence) and patchily distributed. We find that modeling the spatial correlation using a random effect with an intrinsic Gaussian conditionally autoregressive prior distribution was equivalent or superior to Bayesian autologistic regression in terms of predicting to un-sampled areas when strip adaptive cluster sampling was used to survey B. inermis. However, inferences about the relationships between B. inermis presence and environmental predictors differed between the two spatial binary models. The strip adaptive cluster designs we investigate provided a significant advantage in terms of Markov chain Monte Carlo chain convergence when trying to model a sparsely distributed species across a large area. In general, there was little difference in the choice of neighborhood, although the adaptive king was preferred when transects were randomly placed throughout the spatial domain.

  18. Allergic contact dermatitis from exotic woods: importance of patch-testing with patient-provided samples.

    Science.gov (United States)

    Podjasek, Joshua O; Cook-Norris, Robert H; Richardson, Donna M; Drage, Lisa A; Davis, Mark D P

    2011-01-01

    Exotic woods from tropical and subtropical regions (eg, from South America, south Asia, and Africa) frequently are used occupationally and recreationally by woodworkers and hobbyists. These exotic woods more commonly provoke irritant contact dermatitis reactions, but they also can provoke allergic contact dermatitis reactions. We report three patients seen at Mayo Clinic (Rochester, MN) with allergic contact dermatitis reactions to exotic woods. Patch testing was performed and included patient-provided wood samples. Avoidance of identified allergens was recommended. For all patients, the dermatitis cleared or improved after avoidance of the identified allergens. Clinicians must be aware of the potential for allergic contact dermatitis reactions to compounds in exotic woods. Patch testing should be performed with suspected woods for diagnostic confirmation and allowance of subsequent avoidance of the allergens.

  19. Importance of long-time simulations for rare event sampling in zinc finger proteins.

    Science.gov (United States)

    Godwin, Ryan; Gmeiner, William; Salsbury, Freddie R

    2016-01-01

    Molecular dynamics (MD) simulation methods have seen significant improvement since their inception in the late 1950s. Constraints of simulation size and duration that once impeded the field have lessened with the advent of better algorithms, faster processors, and parallel computing. With newer techniques and hardware available, MD simulations of more biologically relevant timescales can now sample a broader range of conformational and dynamical changes including rare events. One concern in the literature has been under which circumstances it is sufficient to perform many shorter timescale simulations and under which circumstances fewer longer simulations are necessary. Herein, our simulations of the zinc finger NEMO (2JVX) using multiple simulations of length 15, 30, 1000, and 3000 ns are analyzed to provide clarity on this point.

  20. Study of a MEMS-based Shack-Hartmann wavefront sensor with adjustable pupil sampling for astronomical adaptive optics.

    Science.gov (United States)

    Baranec, Christoph; Dekany, Richard

    2008-10-01

    We introduce a Shack-Hartmann wavefront sensor for adaptive optics that enables dynamic control of the spatial sampling of an incoming wavefront using a segmented mirror microelectrical mechanical systems (MEMS) device. Unlike a conventional lenslet array, subapertures are defined by either segments or groups of segments of a mirror array, with the ability to change spatial pupil sampling arbitrarily by redefining the segment grouping. Control over the spatial sampling of the wavefront allows for the minimization of wavefront reconstruction error for different intensities of guide source and different atmospheric conditions, which in turn maximizes an adaptive optics system's delivered Strehl ratio. Requirements for the MEMS devices needed in this Shack-Hartmann wavefront sensor are also presented.

  1. A Modified Trap for Adult Sampling of Medically Important Flies (Insecta: Diptera

    Directory of Open Access Journals (Sweden)

    Kamran Akbarzadeh

    2012-12-01

    Full Text Available Background: Bait-trapping appears to be a generally useful method of studying fly populations. The aim of this study was to construct a new adult flytrap by some modifications in former versions and to evaluate its applicability in a subtropical zone in southern Iran.Methods: The traps were constructed with modification by adding some equipment to a polyethylene container (18× 20× 33 cm with lid. The fresh sheep meat was used as bait. Totally 27 adult modified traps were made and tested for their efficacies to attract adult flies. The experiment was carried out in a range of different topographic areas of Fars Province during June 2010.Results: The traps were able to attract various groups of adult flies belonging to families of: Calliphoridae, Sarcophagidae, Muscidae, and Faniidae. The species of Calliphora vicina (Diptera: Calliphoridae, Sarcophaga argyrostoma (Diptera: Sarcophagidae and Musca domestica (Diptera: Muscidae include the majority of the flies collected by this sheep-meat baited trap.Conclusion: This adult flytrap can be recommended for routine field sampling to study diversity and population dynamics of flies where conducting of daily collection is difficult.

  2. Importance of Sample Size for the Estimation of Repeater F Waves in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Jia Fang

    2015-01-01

    Full Text Available Background: In amyotrophic lateral sclerosis (ALS, repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size. Methods: We studied the F waves of left ulnar nerves in ALS patients. Based on the presence or absence of pyramidal signs in the left upper limb, the ALS patients were divided into two groups: One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group. The Index repeating neurons (RN and Index repeater F waves (Freps were compared among the P, NP and control groups following 20 and 100 stimuli respectively. For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared. Results: In the P group, the Index RN (P = 0.004 and Index Freps (P = 0.001 obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052 and Index Freps (P = 0.079; The Index RN (P < 0.001 and Index Freps (P < 0.001 of the P group were significantly higher than the control group; The Index RN (P = 0.002 of the NP group was significantly higher than the control group. For F waves obtained from 100 stimuli, the Index RN (P < 0.001 and Index Freps (P < 0.001 of the P group were significantly higher than the NP group; The Index RN (P < 0.001 and Index Freps (P < 0.001 of the P and NP groups were significantly higher than the control group. Conclusions: Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS. For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy, 100 stimuli would be required.

  3. Importance of Sample Size for the Estimation of Repeater F Waves in Amyotrophic Lateral Sclerosis

    Institute of Scientific and Technical Information of China (English)

    Jia Fang; Ming-Sheng Liu; Yu-Zhou Guan; Bo Cui; Li-Ying Cui

    2015-01-01

    Background:In amyotrophic lateral sclerosis (ALS),repeater F waves are increased.Accurate assessment of repeater F waves requires an adequate sample size.Methods:We studied the F waves of left ulnar nerves in ALS patients.Based on the presence or absence of pyramidal signs in the left upper limb,the ALS patients were divided into two groups:One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group.The Index repeating neurons (RN) and Index repeater F waves (Freps) were compared among the P,NP and control groups following 20 and 100 stimuli respectively.For each group,the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.Results:In the P group,the Index RN (P =0.004) and Index Freps (P =0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli.For F waves obtained from 20 stimuli,no significant differences were identified between the P and NP groups for Index RN (P =0.052) and Index Freps (P =0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P =0.002) of the NP group was significantly higher than the control group.For F waves obtained from 100 stimuli,the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P and NP groups were significantly higher than the control group.Conclusions:Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS.For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy,100 stimuli would be required.

  4. 76 FR 65165 - Importation of Plants for Planting; Risk-Based Sampling and Inspection Approach and Propagative...

    Science.gov (United States)

    2011-10-20

    ... plant part) for or capable of propagation, including a tree, a tissue culture, a plantlet culture... articles (other than seeds, bulbs, or sterile cultures of orchid plants) from any country or locality... Animal and Plant Health Inspection Service Importation of Plants for Planting; Risk-Based Sampling...

  5. Spatiotonal adaptivity in super-resolution of under-sampled image sequences

    NARCIS (Netherlands)

    Pham, T.Q.

    2006-01-01

    This thesis concerns the use of spatial and tonal adaptivity in improving the resolution of aliased image sequences under scene or camera motion. Each of the five content chapters focuses on a different subtopic of super-resolution: image registration (chapter 2), image fusion (chapter 3 and 4), sup

  6. Research on non-uniform sampling problem when adapting wavenumber algorithm to multiple-receiver synthetic aperture sonar

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The azimuth sampling of multiple-receiver SAS systems is non-uniform,which causes standard wavenumber algorithm(ω—κ) can't be applied to multiple-receiver SAS image reconstruction.To solve the problem,two methods are presented,which can adapt the standardω—κalgorithm to multiple-receiver SAS system.One method named Non-uniform Separate Fourier Transform(NSFFT) converts the Fourier Transform(FT) of the non-uniform samples in azimuth direction into several uniform FTs on the assumption that the sonar array...

  7. An adaptive sampling algorithm for Doppler-shift fluorescence velocimetry in high-speed flows

    Science.gov (United States)

    Le Page, Laurent M.; O'Byrne, Sean

    2017-03-01

    We present an approach to improving the efficiency of obtaining samples over a given domain for the peak location of Gaussian line-shapes. The method uses parameter estimates obtained from previous measurements to determine subsequent sampling locations. The method may be applied to determine the location of a spectral peak, where the monetary or time cost is too high to allow a less efficient search method, such as sampling at uniformly distributed domain locations, to be used. We demonstrate the algorithm using linear least-squares fitting of log-scaled planar laser-induced fluorescence data combined with Monte-Carlo simulation of measurements, to accurately determine the Doppler-shifted fluorescence peak frequency for each pixel of a fluorescence image. A simulated comparison between this approach and a uniformly spaced sampling approach is carried out using fits both for a single pixel and for a collection of pixels representing the fluorescence images that would be obtained in a hypersonic flow facility. In all cases, the peak location of Doppler-shifted line-shapes were determined to a similar precision with fewer samples than could be achieved using the more typical uniformly distributed sampling approach.

  8. THE IMPORTANCE OF THE MAGNETIC FIELD FROM AN SMA-CSO-COMBINED SAMPLE OF STAR-FORMING REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Patrick M.; Tang, Ya-Wen; Ho, Paul T. P.; Chen, Huei-Ru Vivien; Liu, Hau-Yu Baobab; Yen, Hsi-Wei; Lai, Shih-Ping [Academia Sinica, Institute of Astronomy and Astrophysics, Taipei, Taiwan (China); Zhang, Qizhou; Chen, How-Huan; Ching, Tao-Chung [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Girart, Josep M. [Institut de Ciències de l' Espai, CSIC-IEEC, Campus UAB, Facultat de Ciències, C5p 2, 08193 Bellaterra, Catalonia (Spain); Frau, Pau [Observatorio Astronómico Nacional, Alfonso XII, 3 E-28014 Madrid (Spain); Li, Hua-Bai [Department of Physics, The Chinese University of Hong Kong (Hong Kong); Li, Zhi-Yun [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Padovani, Marco [Laboratoire Univers et Particules de Montpellier, UMR 5299 du CNRS, Université de Montpellier II, place E. Bataillon, cc072, F-34095 Montpellier (France); Qiu, Keping [School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjiing 210093 (China); Rao, Ramprasad, E-mail: pmkoch@asiaa.sinica.edu.tw [Academia Sinica, Institute of Astronomy and Astrophysics, 645 N. Aohoku Place, Hilo, HI 96720 (United States)

    2014-12-20

    Submillimeter dust polarization measurements of a sample of 50 star-forming regions, observed with the Submillimeter Array (SMA) and the Caltech Submillimeter Observatory (CSO) covering parsec-scale clouds to milliparsec-scale cores, are analyzed in order to quantify the magnetic field importance. The magnetic field misalignment δ—the local angle between magnetic field and dust emission gradient—is found to be a prime observable, revealing distinct distributions for sources where the magnetic field is preferentially aligned with or perpendicular to the source minor axis. Source-averaged misalignment angles (|δ|) fall into systematically different ranges, reflecting the different source-magnetic field configurations. Possible bimodal (|δ|) distributions are found for the separate SMA and CSO samples. Combining both samples broadens the distribution with a wide maximum peak at small (|δ|) values. Assuming the 50 sources to be representative, the prevailing source-magnetic field configuration is one that statistically prefers small magnetic field misalignments |δ|. When interpreting |δ| together with a magnetohydrodynamics force equation, as developed in the framework of the polarization-intensity gradient method, a sample-based log-linear scaling fits the magnetic field tension-to-gravity force ratio (Σ {sub B}) versus (|δ|) with (Σ {sub B}) = 0.116 · exp (0.047 · (|δ|)) ± 0.20 (mean error), providing a way to estimate the relative importance of the magnetic field, only based on measurable field misalignments |δ|. The force ratio Σ {sub B} discriminates systems that are collapsible on average ((Σ {sub B}) < 1) from other molecular clouds where the magnetic field still provides enough resistance against gravitational collapse ((Σ {sub B}) > 1). The sample-wide trend shows a transition around (|δ|) ≈ 45°. Defining an effective gravitational force ∼1 – (Σ {sub B}), the average magnetic-field-reduced star formation efficiency is at least a

  9. Adaptive robust image registration approach based on adequately sampling polar transform and weighted angular projection function

    Science.gov (United States)

    Wei, Zhao; Tao, Feng; Jun, Wang

    2013-10-01

    An efficient, robust, and accurate approach is developed for image registration, which is especially suitable for large-scale change and arbitrary rotation. It is named the adequately sampling polar transform and weighted angular projection function (ASPT-WAPF). The proposed ASPT model overcomes the oversampling problem of conventional log-polar transform. Additionally, the WAPF presented as the feature descriptor is robust to the alteration in the fovea area of an image, and reduces the computational cost of the following registration process. The experimental results show two major advantages of the proposed method. First, it can register images with high accuracy even when the scale factor is up to 10 and the rotation angle is arbitrary. However, the maximum scaling estimated by the state-of-the-art algorithms is 6. Second, our algorithm is more robust to the size of the sampling region while not decreasing the accuracy of the registration.

  10. Efficient Bayes-Adaptive Reinforcement Learning using Sample-Based Search

    CERN Document Server

    Guez, Arthur; Dayan, Peter

    2012-01-01

    Bayesian model-based reinforcement learning is a formally elegant approach to learning optimal behaviour under model uncertainty. In this setting, a Bayes-optimal policy captures the ideal trade-off between exploration and exploitation. Unfortunately, finding Bayes-optimal policies is notoriously taxing due to the enormous search space in the augmented belief-state MDP. In this paper we exploit recent advances in sample-based planning, based on Monte-Carlo tree search, to introduce a tractable method for approximate Bayes-optimal planning. Unlike prior work in this area, we avoid expensive applications of Bayes rule within the search tree, by lazily sampling models from the current beliefs. Our approach outperformed prior Bayesian model-based RL algorithms by a significant margin on several well-known benchmark problems.

  11. SAMPLING ADAPTIVE STRATEGY AND SPATIAL ORGANISATION ESTIMATION OF SOIL ANIMAL COMMUNITIES AT VARIOUS HIERARCHICAL LEVELS OF URBANISED TERRITORIES

    Directory of Open Access Journals (Sweden)

    Baljuk J.A.

    2014-12-01

    Full Text Available In work the algorithm of adaptive strategy of optimum spatial sampling for studying of the spatial organisation of communities of soil animals in the conditions of an urbanization have been presented. As operating variables the principal components obtained as a result of the analysis of the field data on soil penetration resistance, soils electrical conductivity and density of a forest stand, collected on a quasiregular grid have been used. The locations of experimental polygons have been stated by means of program ESAP. The sampling has been made on a regular grid within experimental polygons. The biogeocoenological estimation of experimental polygons have been made on a basis of A.L.Belgard's ecomorphic analysis. The spatial configuration of biogeocoenosis types has been established on the basis of the data of earth remote sensing and the analysis of digital elevation model. The algorithm was suggested which allows to reveal the spatial organisation of soil animal communities at investigated point, biogeocoenosis, and landscape.

  12. Adaptation of ATI-R Scale to Turkish Samples: Validity and Reliability Analyses

    Science.gov (United States)

    Tezci, Erdogan

    2017-01-01

    Teachers' teaching approaches have become an important issue in the search of quality in education and teaching because of their effect on students' learning. Improvements in teachers' knowledge and awareness of their own teaching approaches enable them to adopt teaching process in accordance with their students' learning styles. The Approaches to…

  13. Preliminary Efficacy of Adapted Responsive Teaching for Infants at Risk of Autism Spectrum Disorder in a Community Sample

    Directory of Open Access Journals (Sweden)

    Grace T. Baranek

    2015-01-01

    Full Text Available This study examined the (a feasibility of enrolling 12-month-olds at risk of ASD from a community sample into a randomized controlled trial, (b subsequent utilization of community services, and (c potential of a novel parent-mediated intervention to improve outcomes. The First Year Inventory was used to screen and recruit 12-month-old infants at risk of ASD to compare the effects of 6–9 months of Adapted Responsive Teaching (ART versus referral to early intervention and monitoring (REIM. Eighteen families were followed for ~20 months. Assessments were conducted before randomization, after treatment, and at 6-month follow-up. Utilization of community services was highest for the REIM group. ART significantly outperformed REIM on parent-reported and observed measures of child receptive language with good linear model fit. Multiphase growth models had better fit for more variables, showing the greatest effects in the active treatment phase, where ART outperformed REIM on parental interactive style (less directive, child sensory responsiveness (less hyporesponsive, and adaptive behavior (increased communication and socialization. This study demonstrates the promise of a parent-mediated intervention for improving developmental outcomes for infants at risk of ASD in a community sample and highlights the utility of earlier identification for access to community services earlier than standard practice.

  14. Adaptive foveated single-pixel imaging with dynamic super-sampling

    CERN Document Server

    Phillips, David B; Taylor, Jonathan M; Edgar, Matthew P; Barnett, Stephen M; Gibson, Graham G; Padgett, Miles J

    2016-01-01

    As an alternative to conventional multi-pixel cameras, single-pixel cameras enable images to be recorded using a single detector that measures the correlations between the scene and a set of patterns. However, to fully sample a scene in this way requires at least the same number of correlation measurements as there are pixels in the reconstructed image. Therefore single-pixel imaging systems typically exhibit low frame-rates. To mitigate this, a range of compressive sensing techniques have been developed which rely on a priori knowledge of the scene to reconstruct images from an under-sampled set of measurements. In this work we take a different approach and adopt a strategy inspired by the foveated vision systems found in the animal kingdom - a framework that exploits the spatio-temporal redundancy present in many dynamic scenes. In our single-pixel imaging system a high-resolution foveal region follows motion within the scene, but unlike a simple zoom, every frame delivers new spatial information from acros...

  15. Focussing over the edge: adaptive subsurface laser fabrication up to the sample face.

    Science.gov (United States)

    Salter, P S; Booth, M J

    2012-08-27

    Direct laser writing is widely used for fabrication of subsurface, three dimensional structures in transparent media. However, the accessible volume is limited by distortion of the focussed beam at the sample edge. We determine the aberrated focal intensity distribution for light focused close to the edge of the substrate. Aberrations are modelled by dividing the pupil into two regions, each corresponding to light passing through the top and side facets. Aberration correction is demonstrated experimentally using a liquid crystal spatial light modulator for femtosecond microfabrication in fused silica. This technique allows controlled subsurface fabrication right up to the edge of the substrate. This can benefit a wide range of applications using direct laser writing, including the manufacture of waveguides and photonic crystals.

  16. Adaptation of the Thinking Styles Inventory (TSI within a Romanian student sample

    Directory of Open Access Journals (Sweden)

    Maricutoiu, L.P.

    2014-07-01

    Full Text Available The present paper presents the psychometric properties of the Thinking Styles Inventory (TSI in a sample of 543 Romanian undergraduate students. The TSI is a self-report questionnaire developed for the assessment of 13 types of preferences for problem solving (or thinking styles. The internal reliability analyses indicated that TSI scales have poor reliability (Cronbach's alphas between .26 and .72, with a median value of .62, and these values were slightly improved after we removed of 10 items from the original questionnaire. Confirmatory factor analyses failed to identify an appropriate solution for describing the relationships between the TSI items, indicating poor structural validity of the questionnaire. Further analyses indicated that the sex of the respondent has small effects on TSI scales. Also, results indicated that TSI scales can be used effectively to predict the academic specialization of the respondent.

  17. Evaluation of single and two-stage adaptive sampling designs for estimation of density and abundance of freshwater mussels in a large river

    Science.gov (United States)

    Smith, D.R.; Rogala, J.T.; Gray, B.R.; Zigler, S.J.; Newton, T.J.

    2011-01-01

    Reliable estimates of abundance are needed to assess consequences of proposed habitat restoration and enhancement projects on freshwater mussels in the Upper Mississippi River (UMR). Although there is general guidance on sampling techniques for population assessment of freshwater mussels, the actual performance of sampling designs can depend critically on the population density and spatial distribution at the project site. To evaluate various sampling designs, we simulated sampling of populations, which varied in density and degree of spatial clustering. Because of logistics and costs of large river sampling and spatial clustering of freshwater mussels, we focused on adaptive and non-adaptive versions of single and two-stage sampling. The candidate designs performed similarly in terms of precision (CV) and probability of species detection for fixed sample size. Both CV and species detection were determined largely by density, spatial distribution and sample size. However, designs did differ in the rate that occupied quadrats were encountered. Occupied units had a higher probability of selection using adaptive designs than conventional designs. We used two measures of cost: sample size (i.e. number of quadrats) and distance travelled between the quadrats. Adaptive and two-stage designs tended to reduce distance between sampling units, and thus performed better when distance travelled was considered. Based on the comparisons, we provide general recommendations on the sampling designs for the freshwater mussels in the UMR, and presumably other large rivers.

  18. Importance Sampling Based Decision Trees for Security Assessment and the Corresponding Preventive Control Schemes: the Danish Case Study

    DEFF Research Database (Denmark)

    Liu, Leo; Rather, Zakir Hussain; Chen, Zhe

    2013-01-01

    and adopts a methodology of importance sampling to maximize the information contained in the database so as to increase the accuracy of DT. Further, this paper also studies the effectiveness of DT by implementing its corresponding preventive control schemes. These approaches are tested on the detailed model......Decision Trees (DT) based security assessment helps Power System Operators (PSO) by providing them with the most significant system attributes and guiding them in implementing the corresponding emergency control actions to prevent system insecurity and blackouts. DT is obtained offline from time......-domain simulation and the process of data mining, which is then implemented online as guidelines for preventive control schemes. An algorithm named Classification and Regression Trees (CART) is used to train the DT and key to this approach lies on the accuracy of DT. This paper proposes contingency oriented DT...

  19. The Importance of Sample Return in Establishing Chemical Evidence for Life on Mars or Other Solar System Bodies

    Science.gov (United States)

    Glavin, D. P.; Conrad, P.; Dworkin, J. P.; Eigenbrode, J.; Mahaffy, P. R.

    2011-01-01

    The search for evidence of life on Mars and elsewhere will continue to be one of the primary goals of NASA s robotic exploration program over the next decade. NASA and ESA are currently planning a series of robotic missions to Mars with the goal of understanding its climate, resources, and potential for harboring past or present life. One key goal will be the search for chemical biomarkers including complex organic compounds important in life on Earth. These include amino acids, the monomer building blocks of proteins and enzymes, nucleobases and sugars which form the backbone of DNA and RNA, and lipids, the structural components of cell membranes. Many of these organic compounds can also be formed abiotically as demonstrated by their prevalence in carbonaceous meteorites [1], though, their molecular characteristics may distinguish a biological source [2]. It is possible that in situ instruments may reveal such characteristics, however, return of the right sample (i.e. one with biosignatures or having a high probability of biosignatures) to Earth would allow for more intensive laboratory studies using a broad array of powerful instrumentation for bulk characterization, molecular detection, isotopic and enantiomeric compositions, and spatially resolved chemistry that may be required for confirmation of extant or extinct Martian life. Here we will discuss the current analytical capabilities and strategies for the detection of organics on the Mars Science Laboratory (MSL) using the Sample Analysis at Mars (SAM) instrument suite and how sample return missions from Mars and other targets of astrobiological interest will help advance our understanding of chemical biosignatures in the solar system.

  20. Inferring the demographic history from DNA sequences: An importance sampling approach based on non-homogeneous processes.

    Science.gov (United States)

    Ait Kaci Azzou, S; Larribe, F; Froda, S

    2016-10-01

    In Ait Kaci Azzou et al. (2015) we introduced an Importance Sampling (IS) approach for estimating the demographic history of a sample of DNA sequences, the skywis plot. More precisely, we proposed a new nonparametric estimate of a population size that changes over time. We showed on simulated data that the skywis plot can work well in typical situations where the effective population size does not undergo very steep changes. In this paper, we introduce an iterative procedure which extends the previous method and gives good estimates under such rapid variations. In the iterative calibrated skywis plot we approximate the effective population size by a piecewise constant function, whose values are re-estimated at each step. These piecewise constant functions are used to generate the waiting times of non homogeneous Poisson processes related to a coalescent process with mutation under a variable population size model. Moreover, the present IS procedure is based on a modified version of the Stephens and Donnelly (2000) proposal distribution. Finally, we apply the iterative calibrated skywis plot method to a simulated data set from a rapidly expanding exponential model, and we show that the method based on this new IS strategy correctly reconstructs the demographic history.

  1. Low-discrepancy sampling of parametric surface using adaptive space-filling curves (SFC)

    Science.gov (United States)

    Hsu, Charles; Szu, Harold

    2014-05-01

    Space-Filling Curves (SFCs) are encountered in different fields of engineering and computer science, especially where it is important to linearize multidimensional data for effective and robust interpretation of the information. Examples of multidimensional data are matrices, images, tables, computational grids, and Electroencephalography (EEG) sensor data resulting from the discretization of partial differential equations (PDEs). Data operations like matrix multiplications, load/store operations and updating and partitioning of data sets can be simplified when we choose an efficient way of going through the data. In many applications SFCs present just this optimal manner of mapping multidimensional data onto a one dimensional sequence. In this report, we begin with an example of a space-filling curve and demonstrate how it can be used to find the most similarity using Fast Fourier transform (FFT) through a set of points. Next we give a general introduction to space-filling curves and discuss properties of them. Finally, we consider a discrete version of space-filling curves and present experimental results on discrete space-filling curves optimized for special tasks.

  2. Importance of Mobile Genetic Elements and Conjugal Gene Transfer for Subsurface Microbial Community Adaptation to Biotransformation of Metals

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, Soren J.

    2005-06-01

    The overall goal of this project is to investigate the effect of mobile genetic elements and conjugal gene transfer on subsurface microbial community adaptation to mercury and chromium stress and biotransformation. Our studies focus on the interaction between the fate of these metals in the subsurface and the microbial community structure and activity.

  3. Using adaptive sampling and triangular meshes for the processing and inversion of potential field data

    Science.gov (United States)

    Foks, Nathan Leon

    The interpretation of geophysical data plays an important role in the analysis of potential field data in resource exploration industries. Two categories of interpretation techniques are discussed in this thesis; boundary detection and geophysical inversion. Fault or boundary detection is a method to interpret the locations of subsurface boundaries from measured data, while inversion is a computationally intensive method that provides 3D information about subsurface structure. My research focuses on these two aspects of interpretation techniques. First, I develop a method to aid in the interpretation of faults and boundaries from magnetic data. These processes are traditionally carried out using raster grid and image processing techniques. Instead, I use unstructured meshes of triangular facets that can extract inferred boundaries using mesh edges. Next, to address the computational issues of geophysical inversion, I develop an approach to reduce the number of data in a data set. The approach selects the data points according to a user specified proxy for its signal content. The approach is performed in the data domain and requires no modification to existing inversion codes. This technique adds to the existing suite of compressive inversion algorithms. Finally, I develop an algorithm to invert gravity data for an interfacing surface using an unstructured mesh of triangular facets. A pertinent property of unstructured meshes is their flexibility at representing oblique, or arbitrarily oriented structures. This flexibility makes unstructured meshes an ideal candidate for geometry based interface inversions. The approaches I have developed provide a suite of algorithms geared towards large-scale interpretation of potential field data, by using an unstructured representation of both the data and model parameters.

  4. Predicting the impacts of climate change on animal distributions: the importance of local adaptation and species' traits

    Energy Technology Data Exchange (ETDEWEB)

    HELLMANN, J. J.; LOBO, N. F.

    2011-12-20

    The geographic range limits of many species are strongly affected by climate and are expected to change under global warming. For species that are able to track changing climate over broad geographic areas, we expect to see shifts in species distributions toward the poles and away from the equator. A number of ecological and evolutionary factors, however, could restrict this shifting or redistribution under climate change. These factors include restricted habitat availability, restricted capacity for or barriers to movement, or reduced abundance of colonists due the perturbation effect of climate change. This research project examined the last of these constraints - that climate change could perturb local conditions to which populations are adapted, reducing the likelihood that a species will shift its distribution by diminishing the number of potential colonists. In the most extreme cases, species ranges could collapse over a broad geographic area with no poleward migration and an increased risk of species extinction. Changes in individual species ranges are the processes that drive larger phenomena such as changes in land cover, ecosystem type, and even changes in carbon cycling. For example, consider the poleward range shift and population outbreaks of the mountain pine beetle that has decimated millions of acres of Douglas fir trees in the western US and Canada. Standing dead trees cause forest fires and release vast quantities of carbon to the atmosphere. The beetle likely shifted its range because it is not locally adapted across its range, and it appears to be limited by winter low temperatures that have steadily increased in the last decades. To understand range and abundance changes like the pine beetle, we must reveal the extent of adaptive variation across species ranges - and the physiological basis of that adaptation - to know if other species will change as readily as the pine beetle. Ecologists tend to assume that range shifts are the dominant

  5. [Study of the surface tear tension and evaluation of its importance for the retinal physiology and pathology in contact correction and in adaptation to soft contact lenses].

    Science.gov (United States)

    Cherepnin, A I; Smoliakova, G P; Sorokin, E L

    2003-01-01

    The surface lachrymal-fluid (LF) tension was investigated by teardrop dissection in 115 patients with myopia before they were prescribed soft contact lenses (SCL). Such tension was found to be of clinical importance for the development of SCL adaptation disorders. A longer adaptation period in patients with myopia was associated with a low surface LF tension. A high surface LF tension concurrent with the teardrop dissection mode of the destruction type was typical of the pathological nature of SCL adaptation (12.1% of patients). The obtained data are needed to detect timely the risk of dysadaptation disorders and corneal complications before SCL prescription for the purpose of undertaking the pathogenetically substantiated medication to prevent such complications.

  6. RESULTS FROM EPA FUNDED RESEARCH PROGRAMS ON THE IMPORTANCE OF PURGE VOLUME, SAMPLE VOLUME, SAMPLE FLOW RATE AND TEMPORAL VARIATIONS ON SOIL GAS CONCENTRATIONS

    Science.gov (United States)

    Two research studies funded and overseen by EPA have been conducted since October 2006 on soil gas sampling methods and variations in shallow soil gas concentrations with the purpose of improving our understanding of soil gas methods and data for vapor intrusion applications. Al...

  7. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus

    DEFF Research Database (Denmark)

    de Vries, Ronald P.; Riley, Robert; Wiebenga, Ad

    2017-01-01

    Background:  The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight...... here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi....

  8. "Best Practices in Using Large, Complex Samples: The Importance of Using Appropriate Weights and Design Effect Compensation"

    Directory of Open Access Journals (Sweden)

    Jason W. Osborne

    2011-09-01

    Full Text Available Large surveys often use probability sampling in order to obtain representative samples, and these data sets are valuable tools for researchers in all areas of science. Yet many researchers are not formally prepared to appropriately utilize these resources. Indeed, users of one popular dataset were generally found not to have modeled the analyses to take account of the complex sample (Johnson & Elliott, 1998 even when publishing in highly-regarded journals. It is well known that failure to appropriately model the complex sample can substantially bias the results of the analysis. Examples presented in this paper highlight the risk of error of inference and mis-estimation of parameters from failure to analyze these data sets appropriately.

  9. Methodological Adaptations for Investigating the Perceptions of Language-Impaired Adolescents Regarding the Relative Importance of Selected Communication Skills

    Science.gov (United States)

    Reed, Vicki A.; Brammall, Helen

    2006-01-01

    This article describes the systematic and detailed processes undertaken to modify a research methodology for use with language-impaired adolescents. The original methodology had been used previously with normally achieving adolescents and speech pathologists to obtain their opinions about the relative importance of selected communication skills…

  10. Bottom–up protein identifications from microliter quantities of individual human tear samples. Important steps towards clinical relevance.

    Directory of Open Access Journals (Sweden)

    Peter Raus

    2015-12-01

    With 375 confidently identified proteins in the healthy adult tear, the obtained results are comprehensive and in large agreement with previously published observations on pooled samples of multiple patients. We conclude that, to a limited extent, bottom–up tear protein identifications from individual patients may have clinical relevance.

  11. The importance of quality control in validating concentrations of contaminants of emerging concern in source and treated drinking water samples.

    Science.gov (United States)

    A national-scale survey of 247 contaminants of emerging concern (CECs), including organic and inorganic chemical compounds, and microbial contaminants, was conducted in source and treated drinking water samples from 25 treatment plants across the United States. Multiple methods w...

  12. Importance of Mobile Genetic Elements and Conjugal Gene Transfer for Subsurface Microbial Community Adaptation to Biotransformation of Metals

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, Soren J.

    2004-06-01

    Soils used in the present DOE project were obtained from the Field Research Center (FRC) through correspondence with FRC Manager David Watson. We obtained a total of six soils sampled at different distances from the surface: (A) Non-contaminated surface soil from Hinds Creek Floodplain (0 mbs (meter below surface)). (B) Mercury-contaminated surface soil from Lower East Fork Poplar Creek Floodplain (0 mbs). (C) Mercury-contaminated subsurface soil from Lower East Fork Poplar Creek Floodplain (0.5 mbs). (D) Mercury-contaminated subsurface soil from Lower East Fork Poplar Creek Floodplain (1.0 mbs). (E) Non-contaminated surface soil from Ish Creek Floodplain (0 mbs). (F) Non-contaminated surface soil from Ish Creek Floodplain (0.5 mbs).

  13. A Keck Adaptive Optics Survey of a Representative Sample of Gravitationally-Lensed Star-Forming Galaxies: High Spatial Resolution Studies of Kinematics and Metallicity Gradients

    CERN Document Server

    Leethochawalit, Nicha; Ellis, Richard S; Stark, Daniel P; Richard, Johan; Zitrin, Adi; Auger, Matthew

    2015-01-01

    We discuss spatially resolved emission line spectroscopy secured for a total sample of 15 gravitationally lensed star-forming galaxies at a mean redshift of $z\\simeq2$ based on Keck laser-assisted adaptive optics observations undertaken with the recently-improved OSIRIS integral field unit (IFU) spectrograph. By exploiting gravitationally lensed sources drawn primarily from the CASSOWARY survey, we sample these sub-L$^{\\ast}$ galaxies with source-plane resolutions of a few hundred parsecs ensuring well-sampled 2-D velocity data and resolved variations in the gas-phase metallicity. Such high spatial resolution data offers a critical check on the structural properties of larger samples derived with coarser sampling using multiple-IFU instruments. We demonstrate how serious errors of interpretation can only be revealed through better sampling. Although we include four sources from our earlier work, the present study provides a more representative sample unbiased with respect to emission line strength. Contrary t...

  14. Liver kinetics of glucose analogs measured in pigs by PET: importance of dual-input blood sampling

    DEFF Research Database (Denmark)

    Munk, O L; Bass, L; Roelsgaard, K;

    2001-01-01

    Metabolic processes studied by PET are quantified traditionally using compartmental models, which relate the time course of the tracer concentration in tissue to that in arterial blood. For liver studies, the use of arterial input may, however, cause systematic errors to the estimated kinetic....... Hepatic arterial and portal venous blood samples and flows were measured during the scan. The dual-input function was calculated as the flow-weighted input. RESULTS: For both MG and FDG, the compartmental analysis using arterial input led to systematic underestimation of the rate constants for rapid blood...... of conventional arterial sampling underestimated these parameters compared with independent measurements of hepatic flow and hepatic blood volume. In contrast, the linear Gjedde-Patlak analysis, being less informative but more robust, gave similar parameter estimates (K, V) with both input functions...

  15. Fast simulated annealing and adaptive Monte Carlo sampling based parameter optimization for dense optical-flow deformable image registration of 4DCT lung anatomy

    Science.gov (United States)

    Dou, Tai H.; Min, Yugang; Neylon, John; Thomas, David; Kupelian, Patrick; Santhanam, Anand P.

    2016-03-01

    Deformable image registration (DIR) is an important step in radiotherapy treatment planning. An optimal input registration parameter set is critical to achieve the best registration performance with the specific algorithm. Methods In this paper, we investigated a parameter optimization strategy for Optical-flow based DIR of the 4DCT lung anatomy. A novel fast simulated annealing with adaptive Monte Carlo sampling algorithm (FSA-AMC) was investigated for solving the complex non-convex parameter optimization problem. The metric for registration error for a given parameter set was computed using landmark-based mean target registration error (mTRE) between a given volumetric image pair. To reduce the computational time in the parameter optimization process, a GPU based 3D dense optical-flow algorithm was employed for registering the lung volumes. Numerical analyses on the parameter optimization for the DIR were performed using 4DCT datasets generated with breathing motion models and open-source 4DCT datasets. Results showed that the proposed method efficiently estimated the optimum parameters for optical-flow and closely matched the best registration parameters obtained using an exhaustive parameter search method.

  16. 40 CFR 80.583 - What alternative sampling and testing requirements apply to importers who transport motor vehicle...

    Science.gov (United States)

    2010-07-01

    ... requirements apply to importers who transport motor vehicle diesel fuel, NRLM diesel fuel, or ECA marine fuel by truck or rail car? 80.583 Section 80.583 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel...

  17. Cold shock genes cspA and cspB from Caulobacter crescentus are posttranscriptionally regulated and important for cold adaptation.

    Science.gov (United States)

    Mazzon, Ricardo R; Lang, Elza A S; Silva, Carolina A P T; Marques, Marilis V

    2012-12-01

    Cold shock proteins (CSPs) are nucleic acid binding chaperones, first described as being induced to solve the problem of mRNA stabilization after temperature downshift. Caulobacter crescentus has four CSPs: CspA and CspB, which are cold induced, and CspC and CspD, which are induced only in stationary phase. In this work we have determined that the synthesis of both CspA and CspB reaches the maximum levels early in the acclimation phase. The deletion of cspA causes a decrease in growth at low temperature, whereas the strain with a deletion of cspB has a very subtle and transient cold-related growth phenotype. The cspA cspB double mutant has a slightly more severe phenotype than that of the cspA mutant, suggesting that although CspA may be more important to cold adaptation than CspB, both proteins have a role in this process. Gene expression analyses were carried out using cspA and cspB regulatory fusions to the lacZ reporter gene and showed that both genes are regulated at the transcriptional and posttranscriptional levels. Deletion mapping of the long 5'-untranslated region (5'-UTR) of each gene identified a common region important for cold induction, probably via translation enhancement. In contrast to what was reported for other bacteria, these cold shock genes have no regulatory regions downstream from ATG that are important for cold induction. This work shows that the importance of CspA and CspB to C. crescentus cold adaptation, mechanisms of regulation, and pattern of expression during the acclimation phase apparently differs in many aspects from what has been described so far for other bacteria.

  18. Climate impacts on European agriculture and water management in the context of adaptation and mitigation--the importance of an integrated approach.

    Science.gov (United States)

    Falloon, Pete; Betts, Richard

    2010-11-01

    We review and qualitatively assess the importance of interactions and feedbacks in assessing climate change impacts on water and agriculture in Europe. We focus particularly on the impact of future hydrological changes on agricultural greenhouse gas (GHG) mitigation and adaptation options. Future projected trends in European agriculture include northward movement of crop suitability zones and increasing crop productivity in Northern Europe, but declining productivity and suitability in Southern Europe. This may be accompanied by a widening of water resource differences between the North and South, and an increase in extreme rainfall events and droughts. Changes in future hydrology and water management practices will influence agricultural adaptation measures and alter the effectiveness of agricultural mitigation strategies. These interactions are often highly complex and influenced by a number of factors which are themselves influenced by climate. Mainly positive impacts may be anticipated for Northern Europe, where agricultural adaptation may be shaped by reduced vulnerability of production, increased water supply and reduced water demand. However, increasing flood hazards may present challenges for agriculture, and summer irrigation shortages may result from earlier spring runoff peaks in some regions. Conversely, the need for effective adaptation will be greatest in Southern Europe as a result of increased production vulnerability, reduced water supply and increased demands for irrigation. Increasing flood and drought risks will further contribute to the need for robust management practices. The impacts of future hydrological changes on agricultural mitigation in Europe will depend on the balance between changes in productivity and rates of decomposition and GHG emission, both of which depend on climatic, land and management factors. Small increases in European soil organic carbon (SOC) stocks per unit land area are anticipated considering changes in climate

  19. Testing Set-Point Theory in a Swiss National Sample: Reaction and Adaptation to Major Life Events.

    Science.gov (United States)

    Anusic, Ivana; Yap, Stevie C Y; Lucas, Richard E

    2014-12-01

    Set-point theory posits that individuals react to the experience of major life events, but quickly adapt back to pre-event baseline levels of subjective well-being in the years following the event. A large, nationally representative panel study of Swiss households was used to examine set-point theory by investigating the extent of adaptation following the experience of marriage, childbirth, widowhood, unemployment, and disability. Our results demonstrate that major life events are associated with marked change in life satisfaction and, for some events (e.g., marriage, disability), these changes are relatively long lasting even when accounting for normative, age related change.

  20. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting.

    Science.gov (United States)

    Peterson, A Townsend; Moses, Lina M; Bausch, Daniel G

    2014-01-01

    Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.

  1. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting.

    Directory of Open Access Journals (Sweden)

    A Townsend Peterson

    Full Text Available Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.

  2. Optimizing trial design in pharmacogenetics research: comparing a fixed parallel group, group sequential, and adaptive selection design on sample size requirements.

    Science.gov (United States)

    Boessen, Ruud; van der Baan, Frederieke; Groenwold, Rolf; Egberts, Antoine; Klungel, Olaf; Grobbee, Diederick; Knol, Mirjam; Roes, Kit

    2013-01-01

    Two-stage clinical trial designs may be efficient in pharmacogenetics research when there is some but inconclusive evidence of effect modification by a genomic marker. Two-stage designs allow to stop early for efficacy or futility and can offer the additional opportunity to enrich the study population to a specific patient subgroup after an interim analysis. This study compared sample size requirements for fixed parallel group, group sequential, and adaptive selection designs with equal overall power and control of the family-wise type I error rate. The designs were evaluated across scenarios that defined the effect sizes in the marker positive and marker negative subgroups and the prevalence of marker positive patients in the overall study population. Effect sizes were chosen to reflect realistic planning scenarios, where at least some effect is present in the marker negative subgroup. In addition, scenarios were considered in which the assumed 'true' subgroup effects (i.e., the postulated effects) differed from those hypothesized at the planning stage. As expected, both two-stage designs generally required fewer patients than a fixed parallel group design, and the advantage increased as the difference between subgroups increased. The adaptive selection design added little further reduction in sample size, as compared with the group sequential design, when the postulated effect sizes were equal to those hypothesized at the planning stage. However, when the postulated effects deviated strongly in favor of enrichment, the comparative advantage of the adaptive selection design increased, which precisely reflects the adaptive nature of the design.

  3. Virulence characterisation of Salmonella enterica isolates of differing antimicrobial resistance recovered from UK livestock and imported meat samples.

    Directory of Open Access Journals (Sweden)

    Roderick eCard

    2016-05-01

    Full Text Available Salmonella enterica is a foodborne zoonotic pathogen of significant public health concern. We have characterised the virulence and antimicrobial resistance gene content of 95 Salmonella isolates from 11 serovars by DNA microarray recovered from UK livestock or imported meat. Genes encoding resistance to sulphonamides (sul1, sul2, tetracycline (tet(A, tet(B, streptomycin (strA, strB, aminoglycoside (aadA1, aadA2, beta-lactam (blaTEM, and trimethoprim (dfrA17 were common. Virulence gene content differed between serovars; S. Typhimurium formed two subclades based on virulence plasmid presence. Thirteen isolates were selected by their virulence profile for pathotyping using the Galleria mellonella pathogenesis model. Infection with a chicken invasive S. Enteritidis or S. Gallinarum isolate, a multidrug resistant S. Kentucky, or a S. Typhimurium DT104 isolate resulted in high mortality of the larvae; notably presence of the virulence plasmid in S. Typhimurium was not associated with increased larvae mortality. Histopathological examination showed that infection caused severe damage to the Galleria gut structure. Enumeration of intracellular bacteria in the larvae 24 hours post-infection showed increases of up to 7 log above the initial inoculum and transmission electron microscopy (TEM showed bacterial replication in the haemolymph. TEM also revealed the presence of vacuoles containing bacteria in the haemocytes, similar to Salmonella containing vacuoles observed in mammalian macrophages; although there was no evidence from our work of bacterial replication within vacuoles. This work shows that microarrays can be used for rapid virulence genotyping of S. enterica and that the Galleria animal model replicates some aspects of Salmonella infection in mammals. These procedures can be used to help inform on the pathogenicity of isolates that may be antibiotic resistant and have scope to aid the assessment of their potential public and animal health risk.

  4. FACE Analysis as a Fast and Reliable Methodology to Monitor the Sulfation and Total Amount of Chondroitin Sulfate in Biological Samples of Clinical Importance

    Directory of Open Access Journals (Sweden)

    Evgenia Karousou

    2014-06-01

    Full Text Available Glycosaminoglycans (GAGs due to their hydrophilic character and high anionic charge densities play important roles in various (pathophysiological processes. The identification and quantification of GAGs in biological samples and tissues could be useful prognostic and diagnostic tools in pathological conditions. Despite the noteworthy progress in the development of sensitive and accurate methodologies for the determination of GAGs, there is a significant lack in methodologies regarding sample preparation and reliable fast analysis methods enabling the simultaneous analysis of several biological samples. In this report, developed protocols for the isolation of GAGs in biological samples were applied to analyze various sulfated chondroitin sulfate- and hyaluronan-derived disaccharides using fluorophore-assisted carbohydrate electrophoresis (FACE. Applications to biologic samples of clinical importance include blood serum, lens capsule tissue and urine. The sample preparation protocol followed by FACE analysis allows quantification with an optimal linearity over the concentration range 1.0–220.0 µg/mL, affording a limit of quantitation of 50 ng of disaccharides. Validation of FACE results was performed by capillary electrophoresis and high performance liquid chromatography techniques.

  5. The Development and Application of Random Matrix Theory in Adaptive Signal Processing in the Sample Deficient Regime

    Science.gov (United States)

    2014-09-01

    and N00014-11-10426), and the National Science Foundation (NSF Grant ECCS-1102156) for their support. 6 Contents 1 Introduction 13 1.1 Adaptation...of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . 29 2 Random Matrix Theory Methods 33 2.1 Introduction ...Exponentially Weighted SCM . . . . . . 45 7 2.5.2 The Moments and Inverse of the Rectangularly Windowed SCM 49 2.5.3 White Noise Process

  6. Behavioral Regulation, Visual Spatial Maturity in Kindergarten, and the Relationship of School Adaptation in the First Grade for a Sample of Turkish Children.

    Science.gov (United States)

    Özer, Serap

    2016-04-01

    Behavioral regulation has recently become an important variable in research looking at kindergarten and first-grade achievement of children in private and public schools. The purpose of this study was to examine a measure of behavioral regulation, the Head Toes Knees Shoulders Task, and to evaluate its relationship with visual spatial maturity at the end of kindergarten. Later, in first grade, teachers were asked to rate the children (N = 82) in terms of academic and behavioral adaptation. Behavioral regulation and visual spatial maturity were significantly different between the two school types, but ratings by the teachers in the first grade were affected by children's visual spatial maturity rather than by behavioral regulation. Socioeducational opportunities provided by the two types of schools may be more important to school adaptation than behavioral regulation.

  7. Adaptation and evaluation of a rapid test for the diagnosis of sheep scrapie in samples of rectal mucosa.

    Science.gov (United States)

    González, Lorenzo; Horton, Robert; Ramsay, Drew; Toomik, Reet; Leathers, Valerie; Tonelli, Quentin; Dagleish, Mark P; Jeffrey, Martin; Terry, Linda

    2008-03-01

    In recent publications, it was shown that disease-associated prion protein (PrP(d)) accumulates in the lymphoid tissue of the rectal mucosa of a high proportion of scrapie-infected sheep at clinical and preclinical stages, regardless of several host factors; PrP(d) can also be detected in biopsy specimens of rectal mucosa, with an increased probability proportional to age or incubation period and with an efficiency almost identical to that of tonsil biopsies. Rectal biopsies have the advantages of providing higher numbers of lymphoid follicles and of being simpler to perform, which makes them suitable for scrapie screening in the field. In biopsy samples, PrP(d) could be demonstrated by immunohistochemical (IHC) and Western immunoblotting methods, and the purpose of the present study was to optimize and evaluate a "rapid test" for the diagnosis of scrapie in rectal biopsy samples. The HerdChek CWD (chronic wasting disease) antigen EIA (enzyme immunoassay) test was chosen and, once optimized, provided specificity and sensitivity figures of 99.2% and 93.5%, respectively, compared with IHC results in the same samples obtained at a postmortem. The sensitivity of the assay increased from 82.1%, when a single rectal mucosa sample was tested to 99.4% for those sheep in which 3 or more samples were analyzed. Similarly, sensitivity values of the HerdChek CWD antigen EIA test on biopsy samples increased from 95% to 100% for sheep subjected to 1 or 2 sequential biopsies 4 months apart, respectively. Thus, a preclinical diagnosis of scrapie in live sheep can be achieved by a combination of a simple sampling procedure, which can be repeated several times with no detrimental effect for the animals, and a rapid and efficient laboratory method.

  8. Mobile membrane introduction tandem mass spectrometry for on-the-fly measurements and adaptive sampling of VOCs around oil and gas projects in Alberta, Canada

    Science.gov (United States)

    Krogh, E.; Gill, C.; Bell, R.; Davey, N.; Martinsen, M.; Thompson, A.; Simpson, I. J.; Blake, D. R.

    2012-12-01

    The release of hydrocarbons into the environment can have significant environmental and economic consequences. The evolution of smaller, more portable mass spectrometers to the field can provide spatially and temporally resolved information for rapid detection, adaptive sampling and decision support. We have deployed a mobile platform membrane introduction mass spectrometer (MIMS) for the in-field simultaneous measurement of volatile and semi-volatile organic compounds. In this work, we report instrument and data handling advances that produce geographically referenced data in real-time and preliminary data where these improvements have been combined with high precision ultra-trace VOCs analysis to adaptively sample air plumes near oil and gas operations in Alberta, Canada. We have modified a commercially available ion-trap mass spectrometer (Griffin ICX 400) with an in-house temperature controlled capillary hollow fibre polydimethylsiloxane (PDMS) polymer membrane interface and in-line permeation tube flow cell for a continuously infused internal standard. The system is powered by 24 VDC for remote operations in a moving vehicle. Software modifications include the ability to run continuous, interlaced tandem mass spectrometry (MS/MS) experiments for multiple contaminants/internal standards. All data are time and location stamped with on-board GPS and meteorological data to facilitate spatial and temporal data mapping. Tandem MS/MS scans were employed to simultaneously monitor ten volatile and semi-volatile analytes, including benzene, toluene, ethylbenzene and xylene (BTEX), reduced sulfur compounds, halogenated organics and naphthalene. Quantification was achieved by calibrating against a continuously infused deuterated internal standard (toluene-d8). Time referenced MS/MS data were correlated with positional data and processed using Labview and Matlab to produce calibrated, geographical Google Earth data-visualizations that enable adaptive sampling protocols

  9. The two-sample problem for Poisson processes: adaptive tests with a non-asymptotic wild bootstrap approach

    CERN Document Server

    Reynaud-Bouret, Patricia; Laurent, Béatrice

    2012-01-01

    Considering two independent Poisson processes, we address the question of testing equality of their respective intensities. We construct multiple testing procedures from the aggregation of single tests whose testing statistics come from model selection, thresholding and/or kernel estimation methods. The corresponding critical values are computed through a non-asymptotic wild bootstrap approach. The obtained tests are proved to be exactly of level $\\alpha$, and to satisfy non-asymptotic oracle type inequalities. From these oracle type inequalities, we deduce that our tests are adaptive in the minimax sense over a large variety of classes of alternatives based on classical and weak Besov bodies in the univariate case, but also Sobolev and anisotropic Nikol'skii-Besov balls in the multivariate case. A simulation study furthermore shows that they strongly perform in practice.

  10. Factorial Validity and Internal Consistency of Malaysian Adapted Depression Anxiety Stress Scale - 21 in an Adolescent Sample

    Directory of Open Access Journals (Sweden)

    Hairul Anuar Hashim

    2011-01-01

    Full Text Available Background: Psychometrically sound measurement instrument is a fundamental requirement across broad range of research areas. In negative affect research, Depression Anxiety Stress Scale (DASS has been identified as a psychometrically sound instrument to measure depression, anxiety and stress, especially the 21-item version. However, its psychometric properties in adolescents have been less consistent. Objectives: Thus, the present study sought to examine the factorial validity and internal consistency of the adapted 21-item version of DASS in Malaysian adolescents. Method: Using cross-sectional study design, DASS-21 was administered to 750 Malaysian adolescents (Mean age = 13.40 ± 0.49. The data were then analyzed using Confirmatory factor analysis (CFA, in which the original DASS-21 factor structure (depression-stress-anxiety was compared to 8 other alternative models.Results: CFA results revealed a weak support for DASS-21 as a differentiated measure of depression, anxiety and stress in Malaysian adolescents. Extremely high latent factors intercorrelations were observed in the model reflecting original DASS factor structure. On the other hand, despite the best overall fit of a 4-factor model consisting of depression, anxiety, and stress, as well as a general negative affect factor, individual factor loadings for the specific factors were uninterpretable. Although model fit of 1-factor model was inferior when compared the other competing models, this model (1-factor exhibit reasonable model fit. Conclusion: We concluded that the use of Malaysian adapted DASS-21 as a differentiated measure stress, anxiety, and depression in Malaysian adolescent should proceed with caution and further refinement of the scale is necessary before a concrete conclusion can be made.

  11. Field-adapted sampling of whole blood to determine the levels of amodiaquine and its metabolite in children with uncomplicated malaria treated with amodiaquine plus artesunate combination

    Directory of Open Access Journals (Sweden)

    Gustafsson Lars L

    2009-03-01

    Full Text Available Abstract Background Artemisinin combination therapy (ACT has been widely adopted as first-line treatment for uncomplicated falciparum malaria. In Uganda, amodiaquine plus artesunate (AQ+AS, is the alternative first-line regimen to Coartem® (artemether + lumefantrine for the treatment of uncomplicated falciparum malaria. Currently, there are few field-adapted analytical techniques for monitoring amodiaquine utilization in patients. This study evaluates the field applicability of a new method to determine amodiaquine and its metabolite concentrations in whole blood dried on filter paper. Methods Twelve patients aged between 1.5 to 8 years with uncomplicated malaria received three standard oral doses of AQ+AS. Filter paper blood samples were collected before drug intake and at six different time points over 28 days period. A new field-adapted sampling procedure and liquid chromatographic method was used for quantitative determination of amodiaquine and its metabolite in whole blood. Results The sampling procedure was successively applied in the field. Amodiaquine could be quantified for at least three days and the metabolite up to 28 days. All parasites in all the 12 patients cleared within the first three days of treatment and no adverse drug effects were observed. Conclusion The methodology is suitable for field studies. The possibility to determine the concentration of the active metabolite of amodiaquine up to 28 days suggested that the method is sensitive enough to monitor amodiaquine utilization in patients. Amodiaquine plus artesunate seems effective for treatment of falciparum malaria.

  12. A novel β hyper-plane based importance sampling method%基于β面的截断重要抽样法

    Institute of Scientific and Technical Information of China (English)

    张峰; 吕震宙; 赵新攀

    2011-01-01

    A novel β hyper-plane based importance sampling method is presented to estimate failure probability of structure. Based on β section, a virtual hyper-plane tangent to the failure surface, the variable space is separated into the importance region R and the unimportance region S, on which the truncated importance sampling functions hR(x) and hS(x) sue established respectively. The sampling numbers generated from hR(x) and hS(x) are dependent on the contributions of R and S to the failure probability, and they are determined by the iterative simulations. The formulae of the failure probability estimation, the variance and the coefficient of variation are derived for the presented β hyper-plane importance sampling method. The presented method is suitable for the failure probability estimation of both a single failure mode and multiple failure modes in parallel. The examples show that the presented method is more efficient than the traditional importance sampling method.%提出一种基于β面的截断重要抽样法求解结构单失效模式的失效概率。该方法通过在设计点处作失效面的虚拟切面-β面,将变量空间分割成重要抽样区域R和非重要抽样区域S。在R和S区域分别建立相应的截断重要抽样密度函数hR(x)和hs(x),从hR(x)和hs(x)中抽取的样本量按照R和S区域对失效概率的贡献来分配,由迭代模拟计算得到。推导了基于β面截断重要抽样法的失效概率估计值的方差和变异系数计算公式,该方法还可推广应用到并联系统中。算例结果表明,在相同的计算精度下,基于β面的截断重要抽样法所需的样本数比传统重要抽样法计算量少。

  13. Adaptation and Validation of the Brief Sexual Opinion Survey (SOS) in a Colombian Sample and Factorial Equivalence with the Spanish Version

    Science.gov (United States)

    Sierra, Juan Carlos; Soler, Franklin

    2016-01-01

    Attitudes toward sexuality are a key variable for sexual health. It is really important for psychology and education to have adapted and validated questionnaires to evaluate these attitudes. Therefore, the objective of this research was to adapt, validate and calculate the equivalence of the Colombia Sexual Opinion Survey as compared to the same survey from Spain. To this end, a total of eight experts were consulted and 1,167 subjects from Colombia and Spain answered the Sexual Opinion Survey, the Sexual Assertiveness Scale, the Massachusetts General Hospital-Sexual Functioning Questionnaire, and the Sexuality Scale. The evaluation was conducted by online and the results show adequate qualitative and quantitative properties of the items, with adequate reliability and external validity and compliance with the strong invariance between the two countries. Consequently, the Colombia Sexual Opinion Survey is a valid and reliable scale and its scores can be compared with the ones from the Spain survey, with minimum bias. PMID:27627114

  14. Adaptation of the Participant Role Scale (PRS) in a Spanish youth sample: measurement invariance across gender and relationship with sociometric status.

    Science.gov (United States)

    Lucas-Molina, Beatriz; Williamson, Ariel A; Pulido, Rosa; Calderón, Sonsoles

    2014-11-01

    In recent years, bullying research has transitioned from investigating the characteristics of the bully-victim dyad to examining bullying as a group-level process, in which the majority of children play some kind of role. This study used a shortened adaptation of the Participant Role Scale (PRS) to identify these roles in a representative sample of 2,050 Spanish children aged 8 to 13 years. Confirmatory factor analysis revealed three different roles, indicating that the adapted scale remains a reliable way to distinguish the Bully, Defender, and Outsider roles. In addition, measurement invariance of the adapted scale was examined to analyze possible gender differences among the roles. Peer status was assessed separately by gender through two sociometric procedures: the nominations-based method and the ratings-based method. Across genders, children in the Bully role were more often rated as rejected, whereas Defenders were more popular. Results suggest that although the PRS can reveal several different peer roles in the bullying process, a more clear distinction between bullying roles (i.e., Bully, Assistant, and Reinforcer) could better inform strategies for bullying interventions.

  15. Whole genome resequencing of a laboratory-adapted Drosophila melanogaster population sample [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    William P. Gilks

    2016-11-01

    Full Text Available As part of a study into the molecular genetics of sexually dimorphic complex traits, we used next-generation sequencing to obtain data on genomic variation in an outbred laboratory-adapted fruit fly (Drosophila melanogaster population. We successfully resequenced the whole genome of 220 hemiclonal females that were heterozygous for the same Berkeley reference line genome (BDGP6/dm6, and a unique haplotype from the outbred base population (LHM. The use of a static and known genetic background enabled us to obtain sequences from whole genome phased haplotypes. We used a BWA-Picard-GATK pipeline for mapping sequence reads to the dm6 reference genome assembly, at a median depth of coverage of 31X, and have made the resulting data publicly-available in the NCBI Short Read Archive (Accession number SRP058502. We used Haplotype Caller to discover and genotype 1,726,931 small genomic variants (SNPs and indels, <200bp. Additionally we detected and genotyped 167 large structural variants (1-100Kb in size using GenomeStrip/2.0. Sequence and genotype data are publicly-available at the corresponding NCBI databases: Short Read Archive, dbSNP and dbVar (BioProject PRJNA282591. We have also released the unfiltered genotype data, and the code and logs for data processing and summary statistics (https://zenodo.org/communities/sussex_drosophila_sequencing/.

  16. The relative importance of Staphylococcus saprophyticus as a urinary tract pathogen: distribution of bacteria among urinary samples analysed during 1 year at a major Swedish laboratory.

    Science.gov (United States)

    Eriksson, Andreas; Giske, Christian G; Ternhag, Anders

    2013-01-01

    To determine the distribution of urinary tract pathogens with focus on Staphylococcus saprophyticus and analyse the seasonality, antibiotic susceptibility, and gender and age distributions in a large Swedish cohort. S. saprophyticus is considered an important causative agent of urinary tract infection (UTI) in young women, and some earlier studies have reported up to approximately 40% of UTIs in this patient group being caused by S. saprophyticus. We hypothesized that this may be true only in very specific outpatient settings. During the year 2010, 113,720 urine samples were sent for culture to the Karolinska University Hospital, from both clinics in the hospital and from primary care units. Patient age, gender and month of sampling were analysed for S. saprophyticus, Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. Species data were obtained for 42,633 (37%) of the urine samples. The most common pathogens were E. coli (57.0%), Enterococcus faecalis (6.5%), K. pneumoniae (5.9%), group B streptococci (5.7%), P. mirabilis (3.0%) and S. saprophyticus (1.8%). The majority of subjects with S. saprophyticus were women 15-29 years of age (63.8%). In this age group, S. saprophyticus constituted 12.5% of all urinary tract pathogens. S. saprophyticus is a common urinary tract pathogen in young women, but its relative importance is low compared with E. coli even in this patient group. For women in other ages and for men, growth of S. saprophyticus is a quite uncommon finding.

  17. Enhancing the Frequency Adaptability of Periodic Current Controllers with a Fixed Sampling Rate for Grid-Connected Power Converters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    the instantaneous grid information (e.g., frequency and phase of the grid voltage) for the current control, which is commonly performed by a Phase-Locked-Loop (PLL) system. Hence, harmonics and deviations in the estimated frequency by the PLL could lead to current tracking performance degradation, especially...... of the resonant controllers and by approximating the fractional delay using a Lagrange interpolating polynomial for the RC, respectively, the frequency-variation-immunity of these periodic current controllers with a fixed sampling rate is improved. Experiments on a single-phase grid-connected system are presented...

  18. Assessing an Adaptive Cycle in a Social System under External Pressure to Change: the Importance of Intergroup Relations in Recreational Fisheries Governance

    Directory of Open Access Journals (Sweden)

    Robert Arlinghaus

    2011-06-01

    Full Text Available The adaptive cycle constitutes a heuristic originally used to interpret the dynamics of complex ecosystems in response to disturbance and change. It is assumed that socially constructed governance systems go through similar phases (K, Ω [omega], α [alpha], r as evident in ecological adaptive cycles. Two key dimensions of change shaping the four phases of an adaptive cycle are the degree of connectedness and the range of potential in the system. Our purpose was to quantitatively assess the four phases of the adaptive cycle in a social system by measuring the potential and connectedness dimensions and their different levels in each of the four phases. We assessed these dimensions using quantitative data from content analysis of magazine articles describing the transition process of East German recreational fisheries governance after the fall of the Berlin Wall in 1989. This process was characterized by the discussion of two governance alternatives amendable for implementation: a central East German and a decentralized West German approach. Contrary to assumptions in the adaptive cycle heuristic, we were unable to identify the four phases of the adaptive cycle in our governance system based on quantitatively assessed levels of connectedness and potential alone. However, the insertion of in-group (East Germans and out-group (West Germans dimensions representing the two governance alternatives in our analysis enabled us to identify the specific time frames for all four phases of the adaptive cycle on a monthly basis. These findings suggest that an unmodified "figure-eight model" of the adaptive cycle may not necessarily hold in social systems. Inclusion of disciplinary theories such as intergroup relation theory will help in understanding adaptation processes in social systems.

  19. Slice Sampling

    CERN Document Server

    Neal, R M

    2000-01-01

    Markov chain sampling methods that automatically adapt to characteristics of the distribution being sampled can be constructed by exploiting the principle that one can sample from a distribution by sampling uniformly from the region under the plot of its density function. A Markov chain that converges to this uniform distribution can be constructed by alternating uniform sampling in the vertical direction with uniform sampling from the horizontal `slice' defined by the current vertical position, or more generally, with some update that leaves the uniform distribution over this slice invariant. Variations on such `slice sampling' methods are easily implemented for univariate distributions, and can be used to sample from a multivariate distribution by updating each variable in turn. This approach is often easier to implement than Gibbs sampling, and more efficient than simple Metropolis updates, due to the ability of slice sampling to adaptively choose the magnitude of changes made. It is therefore attractive f...

  20. AdBagging:自适应抽样参数在线装袋算法%AdBagging: adaptive sampling parameters online bagging algorithm

    Institute of Scientific and Technical Information of China (English)

    李小斌; 李世银

    2011-01-01

    By analyzing the concept drift problem in data stream classification, a new algorithm based on online bagging algorithm named adaptive lambda bagging algorithm (AdBagging) is introduced. The new algorithm dynamically adjusts the sampling parameters of Poisson distribution in online bagging algorithm based on the number of misclassified samples in data stream classification. Through this procedure the new algorithm could give more attention to the misclassified samples and give little attention to the right classified samples. At the same time the learning weight of samples for algorithm can be adjusted according to the temporal order. So the algorithm could solve the concept drift problem in data stream classification. Experiments on synthesize and real data sets prove that the algorithm is effective.%通过对数据流分类中的概念漂移问题的研究,提出了一种在线装袋(Online Bagging)算法的改进算法——自适应抽样参数的在线装袋算法AdBagging(adaptive lambda bagging).利用在分类过程中出现的误分样本数量来调整Online Bagging算法中的泊松(Poisson)分布的抽样参数,从而可以动态调整新样本在学习器中的权重,即对于数据流中的误分类样本给予较高的学习权重因子,而对于正确分类的样本给予较低的学习权重因子,同时结合样本出现的时间顺序调整权重因子,使得集成分类器可以动态调整其多样性(adversity).该算法具有Online Bagging算法的高效简洁优点,并能解决数据流中具有概念漂移的问题,人工数据集和实际数据集上的实验结果表明了该算法的有效性.

  1. Computationally efficient video restoration for Nyquist sampled imaging sensors combining an affine-motion-based temporal Kalman filter and adaptive Wiener filter.

    Science.gov (United States)

    Rucci, Michael; Hardie, Russell C; Barnard, Kenneth J

    2014-05-01

    In this paper, we present a computationally efficient video restoration algorithm to address both blur and noise for a Nyquist sampled imaging system. The proposed method utilizes a temporal Kalman filter followed by a correlation-model based spatial adaptive Wiener filter (AWF). The Kalman filter employs an affine background motion model and novel process-noise variance estimate. We also propose and demonstrate a new multidelay temporal Kalman filter designed to more robustly treat local motion. The AWF is a spatial operation that performs deconvolution and adapts to the spatially varying residual noise left in the Kalman filter stage. In image areas where the temporal Kalman filter is able to provide significant noise reduction, the AWF can be aggressive in its deconvolution. In other areas, where less noise reduction is achieved with the Kalman filter, the AWF balances the deconvolution with spatial noise reduction. In this way, the Kalman filter and AWF work together effectively, but without the computational burden of full joint spatiotemporal processing. We also propose a novel hybrid system that combines a temporal Kalman filter and BM3D processing. To illustrate the efficacy of the proposed methods, we test the algorithms on both simulated imagery and video collected with a visible camera.

  2. Estimation of number and density, and random distribution testing of important plant species in Ban Pong Forest, Sansai District, Chiang Mai Province, Thailand using T-Square sampling

    Directory of Open Access Journals (Sweden)

    Phahol Sakkatat

    Full Text Available A study by T-square sampling method was conducted to investigate importantplant species in Ban Pong Forest, Sansai district, Chiang Mai province by estimation of theirnumber and density, and testing of their random distribution. The result showed that, therewere 14 kinds of important plant species, viz. Dipterocarpus tuberculatus Roxb., Shoreaobtuse Wall. exBlume, Bridelia retusa (L. A. Juss, Derris scandens Benth., Thysostachyssiamensis, Parinari anamense Hance, Vitex pinnata L.f., Canarium subulatum Guill.,Litsea glutinosa C.B.Roxb., Alphonsea glabrifolia Craib., Pueraria mirifica, Vaticastapfiana van Slooten, Walsura robusta Rox. and Dipterocarpus alatus Roxb. By far,Dipterocarpus tuberculatus Roxb was greatest in number and density, and all of the specieshad random distribution, except Walsura robusta Roxb and Dipterocarpus alatus Roxb

  3. Improvement of near infrared spectroscopic (NIRS) analysis of caffeine in roasted Arabica coffee by variable selection method of stability competitive adaptive reweighted sampling (SCARS)

    Science.gov (United States)

    Zhang, Xuan; Li, Wei; Yin, Bin; Chen, Weizhong; Kelly, Declan P.; Wang, Xiaoxin; Zheng, Kaiyi; Du, Yiping

    2013-10-01

    Coffee is the most heavily consumed beverage in the world after water, for which quality is a key consideration in commercial trade. Therefore, caffeine content which has a significant effect on the final quality of the coffee products requires to be determined fast and reliably by new analytical techniques. The main purpose of this work was to establish a powerful and practical analytical method based on near infrared spectroscopy (NIRS) and chemometrics for quantitative determination of caffeine content in roasted Arabica coffees. Ground coffee samples within a wide range of roasted levels were analyzed by NIR, meanwhile, in which the caffeine contents were quantitative determined by the most commonly used HPLC-UV method as the reference values. Then calibration models based on chemometric analyses of the NIR spectral data and reference concentrations of coffee samples were developed. Partial least squares (PLS) regression was used to construct the models. Furthermore, diverse spectra pretreatment and variable selection techniques were applied in order to obtain robust and reliable reduced-spectrum regression models. Comparing the respective quality of the different models constructed, the application of second derivative pretreatment and stability competitive adaptive reweighted sampling (SCARS) variable selection provided a notably improved regression model, with root mean square error of cross validation (RMSECV) of 0.375 mg/g and correlation coefficient (R) of 0.918 at PLS factor of 7. An independent test set was used to assess the model, with the root mean square error of prediction (RMSEP) of 0.378 mg/g, mean relative error of 1.976% and mean relative standard deviation (RSD) of 1.707%. Thus, the results provided by the high-quality calibration model revealed the feasibility of NIR spectroscopy for at-line application to predict the caffeine content of unknown roasted coffee samples, thanks to the short analysis time of a few seconds and non

  4. The Importance of In Situ Measurements and Sample Return in the Search for Chemical Biosignatures on Mars or other Solar System Bodies (Invited)

    Science.gov (United States)

    Glavin, D. P.; Brinckerhoff, W. B.; Conrad, P. G.; Dworkin, J. P.; Eigenbrode, J. L.; Getty, S.; Mahaffy, P. R.

    2013-12-01

    The search for evidence of life on Mars and elsewhere will continue to be one of the primary goals of NASA's robotic exploration program for decades to come. NASA and ESA are currently planning a series of robotic missions to Mars with the goal of understanding its climate, resources, and potential for harboring past or present life. One key goal will be the search for chemical biomarkers including organic compounds important in life on Earth and their geological forms. These compounds include amino acids, the monomer building blocks of proteins and enzymes, nucleobases and sugars which form the backbone of DNA and RNA, and lipids, the structural components of cell membranes. Many of these organic compounds can also be formed abiotically as demonstrated by their prevalence in carbonaceous meteorites [1], though, their molecular characteristics may distinguish a biological source [2]. It is possible that in situ instruments may reveal such characteristics, however, return of the right samples to Earth (i.e. samples containing chemical biosignatures or having a high probability of biosignature preservation) would enable more intensive laboratory studies using a broad array of powerful instrumentation for bulk characterization, molecular detection, isotopic and enantiomeric compositions, and spatially resolved chemistry that may be required for confirmation of extant or extinct life on Mars or elsewhere. In this presentation we will review the current in situ analytical capabilities and strategies for the detection of organics on the Mars Science Laboratory (MSL) rover using the Sample Analysis at Mars (SAM) instrument suite [3] and discuss how both future advanced in situ instrumentation [4] and laboratory measurements of samples returned from Mars and other targets of astrobiological interest including the icy moons of Jupiter and Saturn will help advance our understanding of chemical biosignatures in the Solar System. References: [1] Cronin, J. R and Chang S. (1993

  5. Adaptive sampling by information maximization

    CERN Document Server

    Machens, C K

    2002-01-01

    The investigation of input-output systems often requires a sophisticated choice of test inputs to make best use of limited experimental time. Here we present an iterative algorithm that continuously adjusts an ensemble of test inputs online, subject to the data already acquired about the system under study. The algorithm focuses the input ensemble by maximizing the mutual information between input and output. We apply the algorithm to simulated neurophysiological experiments and show that it serves to extract the ensemble of stimuli that a given neural system ``expects'' as a result of its natural history.

  6. Face recognition with single training sample per person based on adaptive weighted LBP%自适应加权LBP的单样本人脸识别方法

    Institute of Scientific and Technical Information of China (English)

    赵汝哲; 房斌; 文静

    2012-01-01

    在面对单训练样本的人脸识别问题时,传统人脸识别方法识别率会下降很多,有的方法甚至不能使用.针对单样本人脸识别问题,提出了一种自适应加权LBP方法.方法既提取了纹理信息又包含了分块拓扑信息,更重要的是可以把这些特征用合适的权重融合起来.划分图像并用LBP提取纹理信息;利用方差来完成对特征的自适应加权融合;用最近邻分类器识别结果.在ORL人脸数据库上的实验结果表明,该方法可以有效地提高识别率.%Facing with the problem of face recognition with single training sample per person, the conventional methods will suffer serious performance drop or even fail to work. To solve this problem, this paper proposes an adaptive weighted Local Binary Pattern (LBP) method. It combines both texture feature and topological information with a novel weighted way involving the variance of sub-images. The paper partitions facial images and uses LBP to extract texture feature. It makes use of variance to implement the adaptive weighted fusion for features. The nearest neighbor classifier is adopted for further recognition. Experimental results show a better performance on ORL facial database.

  7. QR code sampling method based on adaptive match%基于自适应匹配的QR码取样方法

    Institute of Scientific and Technical Information of China (English)

    宋贤媛; 张多英

    2015-01-01

    The QR code acquired by camera always comes with some distortion, so it needs to be recognised to the standard QR code before decode. Aimming at the QR coderecognition, distortion and correction is analyzed and studied in this paper. Some inevitable distortion still existed based on the tilt correction and geometric correction;the traditional method can’t sample the QR code accurately. According to the problem, this paper proposes the adaptive match method, acquire the effective sampling region of QRcode by the matching rate of two adjacent pixel row(column). Experiment shows that the method is real-time with good stability, it can sampling the QR code fast and accurately.%通常由相机获取的QR码图像都带有一些失真,所以在译码前需要对获取的QR码图像进行识别以得到标准规格的QR码。针对QR码识别中的失真和校正进行了分析研究,解决了某些QR码经过倾斜校正和几何校正后仍存在一些无法避免的失真而无法被传统方法准确取样的问题,提出了一种自适应匹配取样法,根据相邻行(列)像素的匹配度准确获取QR码的模块有效取样区域。实验证明该方法稳定性好,能够快速准确地对QR码进行取样。

  8. The R Package MitISEM: Mixture of Student-t Distributions using Importance Sampling Weighted Expectation Maximization for Efficient and Robust Simulation

    NARCIS (Netherlands)

    N. Basturk (Nalan); L.F. Hoogerheide (Lennart); A. Opschoor (Anne); H.K. van Dijk (Herman)

    2012-01-01

    textabstractThis paper presents the R package MitISEM, which provides an automatic and flexible method to approximate a non-elliptical target density using adaptive mixtures of Student-t densities, where only a kernel of the target density is required. The approximation can be used as a candidate de

  9. Defining “Normophilic” and “Paraphilic” Sexual Fantasies in a Population‐Based Sample: On the Importance of Considering Subgroups

    Science.gov (United States)

    2015-01-01

    criteria for paraphilia are too inclusive. Suggestions are given to improve the definition of pathological sexual interests, and the crucial difference between SF and sexual interest is underlined. Joyal CC. Defining “normophilic” and “paraphilic” sexual fantasies in a population‐based sample: On the importance of considering subgroups. Sex Med 2015;3:321–330. PMID:26797067

  10. Stochastic Engine Final Report: Applying Markov Chain Monte Carlo Methods with Importance Sampling to Large-Scale Data-Driven Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R E; Johannesson, G; Sengupta, S; Kosovic, B; Carle, S; Franz, G A; Aines, R D; Nitao, J J; Hanley, W G; Ramirez, A L; Newmark, R L; Johnson, V M; Dyer, K M; Henderson, K A; Sugiyama, G A; Hickling, T L; Pasyanos, M E; Jones, D A; Grimm, R J; Levine, R A

    2004-03-11

    Accurate prediction of complex phenomena can be greatly enhanced through the use of data and observations to update simulations. The ability to create these data-driven simulations is limited by error and uncertainty in both the data and the simulation. The stochastic engine project addressed this problem through the development and application of a family of Markov Chain Monte Carlo methods utilizing importance sampling driven by forward simulators to minimize time spent search very large state spaces. The stochastic engine rapidly chooses among a very large number of hypothesized states and selects those that are consistent (within error) with all the information at hand. Predicted measurements from the simulator are used to estimate the likelihood of actual measurements, which in turn reduces the uncertainty in the original sample space via a conditional probability method called Bayesian inferencing. This highly efficient, staged Metropolis-type search algorithm allows us to address extremely complex problems and opens the door to solving many data-driven, nonlinear, multidimensional problems. A key challenge has been developing representation methods that integrate the local details of real data with the global physics of the simulations, enabling supercomputers to efficiently solve the problem. Development focused on large-scale problems, and on examining the mathematical robustness of the approach in diverse applications. Multiple data types were combined with large-scale simulations to evaluate systems with {approx}{sup 10}20,000 possible states (detecting underground leaks at the Hanford waste tanks). The probable uses of chemical process facilities were assessed using an evidence-tree representation and in-process updating. Other applications included contaminant flow paths at the Savannah River Site, locating structural flaws in buildings, improving models for seismic travel times systems used to monitor nuclear proliferation, characterizing the source

  11. Hemoglobina y testosterona: importancia en la aclimatación y adaptación a la altura Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation

    Directory of Open Access Journals (Sweden)

    Gustavo F. Gonzales

    2011-03-01

    Full Text Available Los diferentes tipos de mecanismos que emplea el organismo cuando se enfrenta a una situación de hipoxia incluyen la acomodación, la aclimatación y la adaptación. La acomodación es la respuesta inicial a la exposición aguda a la hipoxia de altura y se caracteriza por aumento de la ventilación y de la frecuencia cardiaca. La aclimatación se presenta en los individuos que están temporalmente expuestos a la altura y, que en cierto grado, les permite tolerar la altura. En esta fase hay un incremento en la eritropoyesis, se incrementa la concentración de hemoglobina y mejora la capacidad de transporte de oxígeno. La adaptación es el proceso de aclimatación natural donde entra en juego las variaciones genéticas y la aclimatación que les permiten a los individuos vivir sin dificultad en la altura. La testosterona es una hormona que regula la eritropoyesis y la ventilación, podría estar asociada con los procesos de aclimatación y adaptación a la altura. La eritrocitosis excesiva que conduce al mal de montaña crónico es causada por una baja saturación arterial de oxígeno, una ineficiencia ventilatoria y reducida respuesta ventilatoria a la hipoxia. La testosterona se incrementa en la exposición aguda en la altura y en los nativos de altura con eritrocitosis excesiva. Los resultados de las investigaciones actuales permitirían concluir que el incremento de la testosterona y de la hemoglobina son buenas para la aclimatación adquirida pues mejoran el transporte de oxígeno pero no para la adaptación a la altura, dado que valores altos de testosterona en suero se asocian con eritrocitosis excesiva.The different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals

  12. Thriving While Engaging in Risk? Examining Trajectories of Adaptive Functioning, Delinquency, and Substance Use in a Nationally Representative Sample of U.S. Adolescents

    Science.gov (United States)

    Warren, Michael T.; Wray-Lake, Laura; Rote, Wendy M.; Shubert, Jennifer

    2016-01-01

    Recent advances in positive youth development theory and research explicate complex associations between adaptive functioning and risk behavior, acknowledging that high levels of both co-occur in the lives of some adolescents. However, evidence on nuanced overlapping developmental trajectories of adaptive functioning and risk has been limited to 1…

  13. Low incidence of clonality in cold water corals revealed through the novel use of standardized protocol adapted to deep sea sampling

    Science.gov (United States)

    Becheler, Ronan; Cassone, Anne-Laure; Noel, Philippe; Mouchel, Olivier; Morrison, Cheryl; Arnaud-Haond, Sophie

    2016-01-01

    Sampling in the deep sea is a technical challenge, which has hindered the acquisition of robust datasets that are necessary to determine the fine-grained biological patterns and processes that may shape genetic diversity. Estimates of the extent of clonality in deep-sea species, despite the importance of clonality in shaping the local dynamics and evolutionary trajectories, have been largely obscured by such limitations. Cold-water coral reefs along European margins are formed mainly by two reef-building species, Lophelia pertusa and Madrepora oculata. Here we present a fine-grained analysis of the genotypic and genetic composition of reefs occurring in the Bay of Biscay, based on an innovative deep-sea sampling protocol. This strategy was designed to be standardized, random, and allowed the georeferencing of all sampled colonies. Clonal lineages discriminated through their Multi-Locus Genotypes (MLG) at 6–7 microsatellite markers could thus be mapped to assess the level of clonality and the spatial spread of clonal lineages. High values of clonal richness were observed for both species across all sites suggesting a limited occurrence of clonality, which likely originated through fragmentation. Additionally, spatial autocorrelation analysis underlined the possible occurrence of fine-grained genetic structure in several populations of both L. pertusa and M. oculata. The two cold-water coral species examined had contrasting patterns of connectivity among canyons, with among-canyon genetic structuring detected in M. oculata, whereas L. pertusa was panmictic at the canyon scale. This study exemplifies that a standardized, random and georeferenced sampling strategy, while challenging, can be applied in the deep sea, and associated benefits outlined here include improved estimates of fine grained patterns of clonality and dispersal that are comparable across sites and among species.

  14. Supporting Adaptive and Adaptable Hypermedia Presentation Semantics

    NARCIS (Netherlands)

    Bulterman, D.C.A.; Rutledge, L.; Hardman, L.; Ossenbruggen, J.R. van

    1999-01-01

    Having the content of a presentation adapt to the needs, resources and prior activities of a user can be an important benefit of electronic documents. While part of this adaptation is related to the encodings of individual data streams, much of the adaptation can/should be guided by the semantics in

  15. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  16. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  17. The importance of correcting for variable probe-sample interactions in AFM-IR spectroscopy: AFM-IR of dried bacteria on a polyurethane film.

    Science.gov (United States)

    Barlow, Daniel E; Biffinger, Justin C; Cockrell-Zugell, Allison L; Lo, Michael; Kjoller, Kevin; Cook, Debra; Lee, Woo Kyung; Pehrsson, Pehr E; Crookes-Goodson, Wendy J; Hung, Chia-Suei; Nadeau, Lloyd J; Russell, John N

    2016-08-02

    AFM-IR is a combined atomic force microscopy-infrared spectroscopy method that shows promise for nanoscale chemical characterization of biological-materials interactions. In an effort to apply this method to quantitatively probe mechanisms of microbiologically induced polyurethane degradation, we have investigated monolayer clusters of ∼200 nm thick Pseudomonas protegens Pf-5 bacteria (Pf) on a 300 nm thick polyether-polyurethane (PU) film. Here, the impact of the different biological and polymer mechanical properties on the thermomechanical AFM-IR detection mechanism was first assessed without the additional complication of polymer degradation. AFM-IR spectra of Pf and PU were compared with FTIR and showed good agreement. Local AFM-IR spectra of Pf on PU (Pf-PU) exhibited bands from both constituents, showing that AFM-IR is sensitive to chemical composition both at and below the surface. One distinct difference in local AFM-IR spectra on Pf-PU was an anomalous ∼4× increase in IR peak intensities for the probe in contact with Pf versus PU. This was attributed to differences in probe-sample interactions. In particular, significantly higher cantilever damping was observed for probe contact with PU, with a ∼10× smaller Q factor. AFM-IR chemical mapping at single wavelengths was also affected. We demonstrate ratioing of mapping data for chemical analysis as a simple method to cancel the extreme effects of the variable probe-sample interactions.

  18. How Stable Is the Personal Past? Stability of Most Important Autobiographical Memories and Life Narratives Across Eight Years in a Life Span Sample.

    Science.gov (United States)

    Köber, Christin; Habermas, Tilmann

    2017-03-23

    Considering life stories as the most individual layer of personality (McAdams, 2013) implies that life stories, similar to personality traits, exhibit some stability throughout life. Although stability of personality traits has been extensively investigated, only little is known about the stability of life stories. We therefore tested the influence of age, of the proportion of normative age-graded life events, and of global text coherence on the stability of the most important memories and of brief entire life narratives as 2 representations of the life story. We also explored whether normative age-graded life events form more stable parts of life narratives. In a longitudinal life span study covering up to 3 measurements across 8 years and 6 age groups (N = 164) the stability of important memories and of entire life narratives was measured as the percentage of events and narrative segments which were repeated in later tellings. Stability increased between ages 8 and 24, leveling off in middle adulthood. Beyond age, stability of life narratives was also predicted by proportion of normative age-graded life events and by causal-motivational text coherence in younger participants. Memories of normative developmental and social transitional life events were more stable than other memories. Stability of segments of life narratives exceeded the stability of single most important memories. Findings are discussed in terms of cognitive, personality, and narrative psychology and point to research questions in each of these fields. (PsycINFO Database Record

  19. Employee and job attributes as predictors of absenteeism in a national sample of workers: the importance of health and dangerous working conditions.

    Science.gov (United States)

    Leigh, J P

    1991-01-01

    This study reports on research which looks for employee and job characteristics which correlate with absenteeism. A large cross-sectional national probability sample of workers employed for at least 20 hr per week is analyzed (n = 1308). The dependent variable is the number of self-reported absences during the past 14 days. Thirty-seven independent variables are considered. Ordinary Least Squares (multiple regressions), two-limit Tobits, and two-part models are used to assess the statistical and practical significance of possible covariates. Statistically significant predictors included health variables such as being overweight, complaining of insomnia, and hazardous working conditions; job characteristics such as inflexible house; and personal variables such as being a mother with small children. Variables reflecting dangerous working conditions appear to be the strongest correlates of absenteeism. Notable variables which do not predict absenteeism include age, race, wages, and job satisfaction. Future research should direct attention toward workers' health and working conditions as covariates of absenteeism, since they are strongly significant in this study and have been neglected by most absenteeism investigators.

  20. Global dust attenuation in disc galaxies: strong variation with specific star formation and stellar mass, and the importance of sample selection

    Science.gov (United States)

    Devour, Brian M.; Bell, Eric F.

    2016-06-01

    We study the relative dust attenuation-inclination relation in 78 721 nearby galaxies using the axis ratio dependence of optical-near-IR colour, as measured by the Sloan Digital Sky Survey, the Two Micron All Sky Survey, and the Wide-field Infrared Survey Explorer. In order to avoid to the greatest extent possible attenuation-driven biases, we carefully select galaxies using dust attenuation-independent near- and mid-IR luminosities and colours. Relative u-band attenuation between face-on and edge-on disc galaxies along the star-forming main sequence varies from ˜0.55 mag up to ˜1.55 mag. The strength of the relative attenuation varies strongly with both specific star formation rate and galaxy luminosity (or stellar mass). The dependence of relative attenuation on luminosity is not monotonic, but rather peaks at M3.4 μm ≈ -21.5, corresponding to M* ≈ 3 × 1010 M⊙. This behaviour stands seemingly in contrast to some older studies; we show that older works failed to reliably probe to higher luminosities, and were insensitive to the decrease in attenuation with increasing luminosity for the brightest star-forming discs. Back-of-the-envelope scaling relations predict the strong variation of dust optical depth with specific star formation rate and stellar mass. More in-depth comparisons using the scaling relations to model the relative attenuation require the inclusion of star-dust geometry to reproduce the details of these variations (especially at high luminosities), highlighting the importance of these geometrical effects.

  1. Human Cytomegalovirus and Human Umbilical Vein Endothelial Cells: Restriction of Primary Isolation to Blood Samples and Susceptibilities of Clinical Isolates from Other Sources to Adaptation

    OpenAIRE

    2002-01-01

    In immunocompromised patients with disseminated infection, human cytomegalovirus (HCMV) is widespread in the microvascular endothelium of multiple organs. Human umbilical vein endothelial cells (HUVEC) were used in parallel to human embryonic lung fibroblasts (HELF) to recover HCMV from blood samples of immunocompromised patients. Using the shell vial technique, comparable median numbers of p72-positive HUVEC and HELF cells were found with the 26 HCMV-positive buffy coat samples out of 150 ex...

  2. Semantic Importance Sampling for Statistical Model Checking

    Science.gov (United States)

    2015-01-16

    approach called Statistical Model Checking (SMC) [16], which relies on Monte - Carlo -based simulations to solve this verification task more scalably...Conclusion Statistical model checking (SMC) is a prominent approach for rigorous analysis of stochastic systems using Monte - Carlo simulations. In this... Monte - Carlo simulations, for computing the bounded probability that a specific event occurs during a stochastic system’s execution. Estimating the

  3. Robust Adaptive Photon Tracing using Photon Path Visibility

    DEFF Research Database (Denmark)

    Hachisuka, Toshiya; Jensen, Henrik Wann

    2011-01-01

    We present a new adaptive photon tracing algorithm which can handle illumination settings that are considered difficult for photon tracing approaches such as outdoor scenes, close-ups of a small part of an illuminated region, and illumination coming through a small gap. The key contribution in our...... algorithm is the use of visibility of photon path as the importance function which ensures that our sampling algorithm focuses on paths that are visible from the given viewpoint. Our sampling algorithm builds on two recent developments in Markov chain Monte Carlo methods: adaptive Markov chain sampling...... and replica exchange. Using these techniques, each photon path is adaptively mutated and it explores the sampling space efficiently without being stuck at a local peak of the importance function. We have implemented this sampling approach in the progressive photon mapping algorithm which provides visibility...

  4. Adaptation and Psychometric Properties of the Self-Efficacy/Social Support for Activity for Persons with Intellectual Disability Scale (SE/SS-AID) in a Spanish Sample

    Science.gov (United States)

    Cuesta-Vargas, Antonio Ignacio; Paz-Lourido, Berta; Lee, Miyoung; Peterson-Besse, Jana J.

    2013-01-01

    Background: In this study we aimed to develop a Spanish version of the Self-Efficacy/Social Support Scales for Activity for persons with Intellectual Disability (SE/SS-AID). Method: A cross-sectional study was carried out in a sample of 117 individuals with intellectual disability (ID). The SE/SS-AID scales were translated into Spanish and their…

  5. 基于柯西不等式的结构可靠度取尾重要抽样法%INTERCEPTING TAIL IMPORTANCE SAMPLING METHOD OF STRUCTURAL RELIABILITY BASED ON CAUCHY-INEQUALITY

    Institute of Scientific and Technical Information of China (English)

    房艳峰; 高华喜

    2013-01-01

    Cauchy-inequality is utilized to analyze and evaluate the variance of the simulation result of the Monte Carlo method with importance sampling technique involved. The concept of medium probability is introduced and the relationship between medium probability and simulation result variance is deduced. And based on this conclusion, the sampling function which will minimum the simulation result variance is figured, and cirque and semi-cirque intercepting tail importance sampling methods, as importance sampling techniques, are built. Especially, the ratio between the sampling function to the original distribution function is constant in the methods and the sampling points distribute in a spherical space, which take the origin as a center and the distance from the origin to the limit state surface as a radius. Furthermore, the quantitative description for the reduction of variance of simulation results can be obtained. The results of example and analysis indicate that the variance of simulation results by cirque and semi-cirque intercepting tail importance sampling methods can be reduced to one tenth and one twentieth of that by a direct method.%该文采用柯西不等式对结构可靠度计算中Monte Carlo重要抽样法的模拟方差进行了分析与评价,提出了中间概率的概念并推导出其与模拟方差的函数关系.在此基础上得出使方差达到极小值的抽样函数具体形式,并建立了属于重要抽样技术的圆环和半圆环取尾抽样方法.与其他方法不同的是其抽样函数与原变量分布函数的比值是一常数,其分布区域是以原点为中心以原点到极限状态面距离为半径的圆形外部空间,模拟结果的方差可以定量描述.理论分析和例题模拟结果都表明:圆环取尾抽样方法可使模拟结果的方差缩减到直接模拟的1/10,而半圆环取尾抽样方法能缩减到1/20.

  6. Separation and enrichment of palladium and gold in biological and environmental samples, adapted to the determination by total reflection X-ray fluorescence.

    Science.gov (United States)

    Messerschmidt, J; von Bohlen, A; Alt, F; Klockenkämper, R

    2000-03-01

    The reductive co-precipitation of trace and ultra-trace elements together with mercury followed by complete evaporation of the mercury makes it possible to determine palladium and gold by total reflection X-ray fluorescence. Both elements can be detected without interferences at optimal sensitivity in the pg range. Thus, detection limits of, e.g., 2.5 ng L-1 for palladium and 2.0 ng L-1 for gold, in urine, were obtained. The precision was determined to 0.04 at a palladium concentration of about 200 ng L-1 urine and to 0.19 at a gold concentration of only 18 ng L-1. The recovery for a urine sample spiked with known amounts of palladium and gold amounted to > 95%. Results of the combined procedure are given for the determination of palladium and gold in the urine of non-exposed and occupationally exposed persons and in some other environmentally relevant samples.

  7. Technology transfer for adaptation

    Science.gov (United States)

    Biagini, Bonizella; Kuhl, Laura; Gallagher, Kelly Sims; Ortiz, Claudia

    2014-09-01

    Technology alone will not be able to solve adaptation challenges, but it is likely to play an important role. As a result of the role of technology in adaptation and the importance of international collaboration for climate change, technology transfer for adaptation is a critical but understudied issue. Through an analysis of Global Environment Facility-managed adaptation projects, we find there is significantly more technology transfer occurring in adaptation projects than might be expected given the pessimistic rhetoric surrounding technology transfer for adaptation. Most projects focused on demonstration and early deployment/niche formation for existing technologies rather than earlier stages of innovation, which is understandable considering the pilot nature of the projects. Key challenges for the transfer process, including technology selection and appropriateness under climate change, markets and access to technology, and diffusion strategies are discussed in more detail.

  8. Some challenges with statistical inference in adaptive designs.

    Science.gov (United States)

    Hung, H M James; Wang, Sue-Jane; Yang, Peiling

    2014-01-01

    Adaptive designs have generated a great deal of attention to clinical trial communities. The literature contains many statistical methods to deal with added statistical uncertainties concerning the adaptations. Increasingly encountered in regulatory applications are adaptive statistical information designs that allow modification of sample size or related statistical information and adaptive selection designs that allow selection of doses or patient populations during the course of a clinical trial. For adaptive statistical information designs, a few statistical testing methods are mathematically equivalent, as a number of articles have stipulated, but arguably there are large differences in their practical ramifications. We pinpoint some undesirable features of these methods in this work. For adaptive selection designs, the selection based on biomarker data for testing the correlated clinical endpoints may increase statistical uncertainty in terms of type I error probability, and most importantly the increased statistical uncertainty may be impossible to assess.

  9. Resilience through adaptation

    Science.gov (United States)

    van Voorn, George A. K.; Ligtenberg, Arend; Molenaar, Jaap

    2017-01-01

    Adaptation of agents through learning or evolution is an important component of the resilience of Complex Adaptive Systems (CAS). Without adaptation, the flexibility of such systems to cope with outside pressures would be much lower. To study the capabilities of CAS to adapt, social simulations with agent-based models (ABMs) provide a helpful tool. However, the value of ABMs for studying adaptation depends on the availability of methodologies for sensitivity analysis that can quantify resilience and adaptation in ABMs. In this paper we propose a sensitivity analysis methodology that is based on comparing time-dependent probability density functions of output of ABMs with and without agent adaptation. The differences between the probability density functions are quantified by the so-called earth-mover’s distance. We use this sensitivity analysis methodology to quantify the probability of occurrence of critical transitions and other long-term effects of agent adaptation. To test the potential of this new approach, it is used to analyse the resilience of an ABM of adaptive agents competing for a common-pool resource. Adaptation is shown to contribute positively to the resilience of this ABM. If adaptation proceeds sufficiently fast, it may delay or avert the collapse of this system. PMID:28196372

  10. 自适应采样间隔的无线传感器网络多目标跟踪算法%Multi-target tracking algorithm based on adaptive sampling interval in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    王建平; 赵高丽; 胡孟杰; 陈伟

    2014-01-01

    Multi-target tracking is a hot topic of current research on wireless sensor networks (WSN ). Based on adaptive sampling interval,we propose a multi-target tracking algorithm in order to save energy consumption and prevent tracking lost for WSN.We contrast the targets moving model by using the position metadata,and predicte the targets moving status based on extended Kalman filter (EKF).we adopt the probability density function (PDF )of the estimated targets to establish the tracking cluster.By defining the tracking center,we use Markov distance to quantify the election process of the main node (MN).We comput targets impact strength through the targets importance and the distance to MN node, and then use it to build tracking algorithm.We do the simulation experiment based on MATLAB,and the experiment results show that the proposed algorithm can accurate predict the trajectory of the targets,and adjust the sampling interval while the targets were moving.By analyzing the experiments data,we know that the proposed algorithm can improve the tracking precision and save the energy consumption of WSN obviously.%多目标跟踪是无线传感器网络当前研究的热点问题。针对多目标跟踪存在耗能较大,跟踪丢失等问题,提出了一种自适应采样间隔的多目标跟踪算法。采用跟踪目标的定位元数据来对目标的运动模式进行建模。基于扩展的卡尔曼滤波器来预测跟踪目标状态,采用预测目标定位的概率密度函数构建跟踪簇。通过定义跟踪目标中心,基于马氏距离来量化主节点 MN 的选举过程。通过跟踪目标重要性和其与MN之间的距离来量化目标的影响强度,并以此构建自适应采样间隔的多目标跟踪算法。基于MATLAB进行了仿真实验,实验结果显示,本文设计的跟踪算法能准确预测目标的运动轨迹,能随着运动目标的状态实时采用自适应的采样间隔。通过数据分析得知,本

  11. F-VIPGI: a new adapted version of VIPGI for FORS2 spectroscopy. Application to a sample of 16 X-ray selected galaxy clusters at 0.6 ≤ z ≤ 1.2

    Science.gov (United States)

    Nastasi, A.; Scodeggio, M.; Fassbender, R.; Böhringer, H.; Pierini, D.; Verdugo, M.; Garilli, B. M.; Franzetti, P.

    2013-02-01

    Aims: The goal of this paper is twofold. Firstly, we present F-VIPGI, a new version of the VIMOS Interactive Pipeline and Graphical Interface (VIPGI) adapted to handle FORS2 spectroscopic data taken with the standard instrument configuration. Secondly, we investigate the spectro-photometric properties of a sample of galaxies residing in distant X-ray selected galaxy clusters, the optical spectra of which were reduced with this new pipeline. Methods: We provide basic technical information about the innovations of the new software and refer the reader to the original VIPGI paper for a detailed description of the core functions and performances. As a demonstration of the capabilities of the new pipeline, we then show results obtained for 16 distant (0.65 ≤ z ≤ 1.25) X-ray luminous galaxy clusters selected within the XMM-Newton Distant Cluster Project. We performed a spectral indices analysis of the extracted optical spectra of their members, based on which we created a library of composite high signal-to-noise ratio spectra. We then compared the average spectra of the passive galaxies of our sample with those computed for the same class of objects that reside in the field at similar high redshift and in groups in the local Universe. Finally, We computed the "photometric" properties of our templates and compared them with those of the Coma Cluster galaxies, which we took as representative of the local cluster population. Results: We demonstrate the capabilities of F-VIPGI, whose strength is an increased efficiency and a simultaneous shortening of FORS2 spectroscopic data reduction time by a factor of ~10 w.r.t. the standard IRAF procedures. We then discuss the quality of the final stacked optical spectra and provide them in electronic form as high-quality spectral templates, representative of passive and star-forming galaxies residing in distant galaxy clusters. By comparing the spectro-photometric properties of our templates with the local and distant galaxy

  12. MOTIVATION IN ADAPTED SPORT

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Torralba

    2014-05-01

    Full Text Available This study examines the motivation for practice of sport of people with disabilities that form part to a federated sport.The sample was composed of 134 athletes of both genders and different disabilities.The “Participation Motivation Inventory Questionnaire” by Gill, Gross and Huddleston was used. The instrument was adapted to Paralympic sport and describes the main reasons that encourage the sports activity practice. The results haven´t found significant difference between men´s and women´s or between blind - visually impaired physical and motor disabilities. About the motivation of the practice of sport, worth highlighting the importance given to factors of fitness and health, like sport practice, improve the level, to compete, feel good and have fun, well above being popular, influenced by coaches or satisfy to parents.

  13. Validation of a simplified field-adapted procedure for routine determinations of methyl mercury at trace levels in natural water samples using species-specific isotope dilution mass spectrometry.

    Science.gov (United States)

    Lambertsson, Lars; Björn, Erik

    2004-12-01

    A field-adapted procedure based on species-specific isotope dilution (SSID) methodology for trace-level determinations of methyl mercury (CH(3)Hg(+)) in mire, fresh and sea water samples was developed, validated and applied in a field study. In the field study, mire water samples were filtered, standardised volumetrically with isotopically enriched CH(3) (200)Hg(+), and frozen on dry ice. The samples were derivatised in the laboratory without further pre-treatment using sodium tetraethyl borate (NaB(C(2)H(5))(4)) and the ethylated methyl mercury was purge-trapped on Tenax columns. The analyte was thermo-desorbed onto a GC-ICP-MS system for analysis. Investigations preceding field application of the method showed that when using SSID, for all tested matrices, identical results were obtained between samples that were freeze-preserved or analysed unpreserved. For DOC-rich samples (mire water) additional experiments showed no difference in CH(3)Hg(+) concentration between samples that were derivatised without pre-treatment or after liquid extraction. Extractions of samples for matrix-analyte separation prior to derivatisation are therefore not necessary. No formation of CH(3)Hg(+) was observed during sample storage and treatment when spiking samples with (198)Hg(2+). Total uncertainty budgets for the field application of the method showed that for analyte concentrations higher than 1.5 pg g(-1) (as Hg) the relative expanded uncertainty (REU) was approximately 5% and dominated by the uncertainty in the isotope standard concentration. Below 0.5 pg g(-1) (as Hg), the REU was >10% and dominated by variations in the field blank. The uncertainty of the method is sufficiently low to accurately determine CH(3)Hg(+) concentrations at trace levels. The detection limit was determined to be 4 fg g(-1) (as Hg) based on replicate analyses of laboratory blanks. The described procedure is reliable, considerably faster and simplified compared to non-SSID methods and thereby very

  14. Origins of adaptive immunity.

    Science.gov (United States)

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity.

  15. Adaptive Rationality, Adaptive Behavior and Institutions

    Directory of Open Access Journals (Sweden)

    Volchik Vyacheslav, V.

    2015-12-01

    Full Text Available The economic literature focused on understanding decision-making and choice processes reveals a vast collection of approaches to human rationality. Theorists’ attention has moved from absolutely rational, utility-maximizing individuals to boundedly rational and adaptive ones. A number of economists have criticized the concepts of adaptive rationality and adaptive behavior. One of the recent trends in the economic literature is to consider humans irrational. This paper offers an approach which examines adaptive behavior in the context of existing institutions and constantly changing institutional environment. It is assumed that adaptive behavior is a process of evolutionary adjustment to fundamental uncertainty. We emphasize the importance of actors’ engagement in trial and error learning, since if they are involved in this process, they obtain experience and are able to adapt to existing and new institutions. The paper aims at identifying relevant institutions, adaptive mechanisms, informal working rules and practices that influence actors’ behavior in the field of Higher Education in Russia (Rostov Region education services market has been taken as an example. The paper emphasizes the application of qualitative interpretative methods (interviews and discourse analysis in examining actors’ behavior.

  16. 非线性结构动力学系统的首次穿越%An important sampling procedure for estimating failure probabilities of non-linear dynamic systems

    Institute of Scientific and Technical Information of China (English)

    任丽梅; 徐伟; 李战国

    2013-01-01

    The failure probability is one of the most important reliability measures in structural reliability assessment of dynamical systems. Here, a procedure for estimating failure probabilities of non-linear systems based on the important sampling technique was presented. Firstly ,by using Rice formula,the equivalent linear version of the non-linear systems was derived. Using the equivalent linear equation, the design point of the equivalent linear systems was used to construct control function. Secondly, an important sampling technique was used to estimate the first excursion probabilities for the non-linear system. Finally, a Duffing oscillator was taken for example. The simulation results showed that the proposed method is correct and effective; the number of samples and the computational time are reduced significantly compared with those of direct Monte Carlo simulations.%在结构动力学系统的可靠性分析中,动力学系统的首次穿越失效一直是研究重点问题之一.基于重要抽样法基础上研究了非线性结构动力学系统的首次穿越.首先根据Rice公式,得到与非线性系统方程具有相同平均上穿率的等效线性化系统方程,利用此等效方程得到设计点的解析表达式,并用此解析式来构造控制函数,最后将此控制函数运用到非线性系统中,利用重要抽样法估计非线性系统的首穿失效概率.以Duffing振子为例,模拟结果显示了方法的正确性与有效性,与原始蒙特卡罗模拟方法相比较,样本数量、计算所需时间都有明显减小.

  17. IMPORTANT NOTIFICATION

    CERN Document Server

    HR Department

    2009-01-01

    Green plates, removals and importation of personal effects Please note that, as from 1 April 2009, formalities relating to K and CD special series French vehicle plates (green plates), removals and importation of personal effects into France and Switzerland will be dealt with by GS Department (Building 73/3-014, tel. 73683/74407). Importation and purchase of tax-free vehicles in Switzerland, as well as diplomatic privileges, will continue to be dealt with by the Installation Service of HR Department (Building 33/1-011, tel. 73962). HR and GS Departments

  18. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial lighting ceases...

  19. From equivalence to adaptation

    Directory of Open Access Journals (Sweden)

    Paulina Borowczyk

    2009-01-01

    Full Text Available The aim of this paper is to illustrate in which cases the translators use the adaptation when they are confronted with a term related to sociocultural aspects. We will discuss the notions of equivalence and adaptation and their limits in the translation. Some samples from Arte TV news and from the American film Shrek translated into Polish, German and French will be provided as a support for this article.

  20. Adaptive Sampling in Autonomous Marine Sensor Networks

    Science.gov (United States)

    2006-06-01

    left.perr > 180.0) left- perr - 360.0 - left.perr; double right.perr - fabs(evalCRS - rightabs); if (right.perr > 180.0) right.perr = 360.0 - right- perr ...if Cright..cerr > 180.0) right-.cerr - 360.0 - right-.cerr; if (left..cerr <- right..cerr) if (left.. perr < right.. perr ) mval - (CC200-left-. perr )/2.0...90.0-left...cerr)/2.0); else mval - (200-right.. perr )/2.0; I else if (right.. perr <- left.. perr ) mval - (CC200-right-. perr )/2.0) + (90.0 -right

  1. Adaptation: A Partially Automated Approach

    OpenAIRE

    Manjing, Tham; Bukhsh, F.A.; Weigand, H.

    2014-01-01

    This paper showcases the possibility of creating an adaptive auditing system. Adaptation in an audit environment need human intervention at some point. Based on a case study this paper focuses on automation of adaptation process. It is divided into solution design and validation parts. The artifact design is developed around import procedures of M-company. An overview of the artefact is discussed in detail to fully describes the adaptation mechanism with automatic adjustment for compliance re...

  2. Appraising Adaptive Management

    Directory of Open Access Journals (Sweden)

    Kai N. Lee

    1999-12-01

    Full Text Available Adaptive management is appraised as a policy implementation approach by examining its conceptual, technical, equity, and practical strengths and limitations. Three conclusions are drawn: (1 Adaptive management has been more influential, so far, as an idea than as a practical means of gaining insight into the behavior of ecosystems utilized and inhabited by humans. (2 Adaptive management should be used only after disputing parties have agreed to an agenda of questions to be answered using the adaptive approach; this is not how the approach has been used. (3 Efficient, effective social learning, of the kind facilitated by adaptive management, is likely to be of strategic importance in governing ecosystems as humanity searches for a sustainable economy.

  3. Adaptively Sharing Time-Series with Differential Privacy

    CERN Document Server

    Fan, Liyue

    2012-01-01

    Sharing real-time aggregate statistics of private data has given much benefit to the public to perform data mining for understanding important phenomena, such as Influenza outbreaks and traffic congestions. We propose an adaptive approach with sampling and estimation to release aggregated time series under differential privacy, the key innovation of which is that we utilize feedback loops based on observed (perturbed) values to dynamically adjust the estimation model as well as the sampling rate. To minimize the overall privacy cost, our solution uses the PID controller to adaptively sample long time-series according to detected data dynamics. To improve the accuracy of data release per timestamp, the Kalman filter is used to predict data values at non-sampling points and to estimate true values from perturbed query answers at sampling points. Our experiments with three real data sets show that it is beneficial to incorporate feedback into both the estimation model and the sampling process. The results confir...

  4. ADAPTATION DEBATE, AHMET VEFİK PAŞA AND ZORAKİ TABİB SAMPLE / ADAPTASYON MESELESİ, AHMET VEFİK PAŞA VE ZORAKİ TABİB ÖRNEĞİ

    Directory of Open Access Journals (Sweden)

    Dr. Bayram YILDIZ

    2007-08-01

    Full Text Available Adaptation, an item of theatre in Turkish literature beginning with Tanzimat, has been opposed since it would have negative effects on development of national theatre and on Turkish society structure. On the other hand adaptation was supported as it would benefit development of modern theatre. Though the common belief was against adaptation, adaptations of Ahmet Vefik Pasa from Moliere have found acceptance. This acceptance might be due to his preference of comedy and of its best performer in world literature, Moliere, and adaptation of plays consistent with Turkish society structure and moral virtues as in the case of Zoraki Tabip.

  5. ADAPT Dataset

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Diagnostics and Prognostics Testbed (ADAPT) Project Lead: Scott Poll Subject Fault diagnosis in electrical power systems Description The Advanced...

  6. Principal component importance sampling for bank credit portfolio risk management%银行信用组合风险多成分重要性抽样算法研究

    Institute of Scientific and Technical Information of China (English)

    龚朴; 邓洋; 胡祖辉

    2012-01-01

    银行信用组合违约风险的度量和计算对银行监管有着重要的意义.使蒙特卡洛研究信用组合违约概率时,为提高模拟效率,越来越多的学者采用了重要性抽样技术来实现.它主要通过条件独立性和“均值移动”两个步骤实现.本文基于前人研究结果的基础之上,提出了一种基于违约相关性矩阵的多因子变方差的重要性抽样算法.该算法通过主成分分析选择违约结构中的占优成分并扩大其方差来实现.数值算例证明了该方法在信用组合遭遇极值事件时,能够提高模拟效率及计算精度,具有一定的计算优势.%The bank credit portfolio risk measurement has great significance to bank supervision. One of the most popular methods to estimate the default probability of credit asset is Monte Carlo simulation. In order to improve the simulation efficiency, more and more studies have adopted the important sampling technique to deal with it. In this paper, we propose an importance sampling procedure which does not need the conditional independence which previous studies had to base on. The procedure we provide uses principal component a-nalysis to choose dominant factors. Numerical experiments are provided and the results show that our approach when a credit portfolio confronts extreme events, offers substantial variance reduction and outperforms plain Monte Carlo algorithm and Morokoff IS algorithm.

  7. 直接压印快速采样法在院内感染环境监测中的重要性分析%Direct Imprint Rapid Sampling Analysis of Importance of Environmental Monitoring of Infection in Hospital

    Institute of Scientific and Technical Information of China (English)

    刘素珍; 张甜; 欧阳琳

    2013-01-01

    目的:对直接压印快速采样法在院内感染环境监测中的重要性进行分析。方法:对2011年6月-2012年5月本院空气、医护人员手部、物体表面、器械、经高压消毒的物品等240份表面细菌数量进行检测,观察组采用直接压印快速采样法,对照组采用传统生理盐水棉拭子涂擦法,对两组的检测效果进行对比分析。结果:观察组细菌数量检出率明显高于对照组,比较差异具有统计学意义(P<0.05)。结论:和传统生理盐水棉拭子涂擦法相比,直接压印快速采样法在院内感染环境的检测采样中有着明显的优势,能够减少众多中间环节所导致的检测结果误差缩短采样到达培养箱中的时间,方便快捷、易操作、经济节约,值得在同级医疗机构中推广应用。%Objective:To analyze direct imprint rapid sampling method in the environmental monitoring of nosocomial infections importance. Method:June 2011 to May 2012 in our hospital air medical hands,surfaces,equipment,items such as autoclaved 240 parts surface bacteria were detected by direct observation group imprint fast sampling method,saline control group using a cotton swab rubbed traditional method,detection results of the two groups were compared. Result:The number of bacteria detection rate of the observation group was significantly higher than that of the control group,the difference was statistically significant(P<0.05). Conclusion:The traditional method compared to saline cotton swab rubbed directly imprint rapid sampling method in the detection of nosocomial infection environmental sampling has obvious advantages,can reduce the number of intermediate links caused by shortening the sampling error of test results arrive incubator time,convenient,easy to operate,economical,worthy of medical institutions at the same level application.

  8. Transformational adaptation when incremental adaptations to climate change are insufficient.

    Science.gov (United States)

    Kates, Robert W; Travis, William R; Wilbanks, Thomas J

    2012-05-08

    All human-environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations.

  9. [Imported histoplasmosis].

    Science.gov (United States)

    Stete, Katarina; Kern, Winfried V; Rieg, Siegbert; Serr, Annerose; Maurer, Christian; Tintelnot, Kathrin; Wagner, Dirk

    2015-06-01

    Infections with Histoplasma capsulatum are rare in Germany, and mostly imported from endemic areas. Infections can present as localized or disseminated diseases in immunocompromised as well as immunocompetent hosts. A travel history may be a major clue for diagnosing histoplasmosis. Diagnostic tools include histology, cultural and molecular detection as well as serology. Here we present four cases of patients diagnosed and treated in Freiburg between 2004 and 2013 that demonstrate the broad range of clinical manifestations of histoplasmosis: an immunocompetent patient with chronic basal meningitis; a patient with HIV infection and fatal disseminated disease; a patient with pulmonary and cutaneous disease and mediastinal and cervical lymphadenopathy; and an immunosuppressed patient with disseminated involvement of lung, bone marrow and adrenal glands.

  10. 基于重要样本法的结构动力学系统的首次穿越%FIRST EXCURSION PROBABILITIES OF DYNAMICAL SYSTEMS BY IMPORTANCE SAMPLING

    Institute of Scientific and Technical Information of China (English)

    任丽梅; 徐伟; 肖玉柱; 王文杰

    2012-01-01

    基于Gisranov定理,提出一种估计稳态高斯白噪声激励的结构动力学系统首穿失效概率的重要样本法.文章重点是构造控制函数,控制函数促使随机响应尽量集中在样本空间中最易导致首次穿越发生的部分.利用设计点构造控制函数,在线性系统场合,结合时不变系统的结构可靠性理论,通过解有约束的优化问题得到设计点;在非线性系统场合,利用Heonsang Koo提出的设计点激励,通过镜像法得到设计点.最后给出例子,将所提方法与原始蒙特卡罗法相比较,模拟结果显示方法的正确性与有效性.%Based on the Girsanov transformation, this paper develops a method for estimating the first excursion probability of dynamical systems with stationary gauss white noise. The focus is to construct control function that concentrates on the samples paths in the "most important part" of the sample space, to achieve the purpose of variance reduction. The paper uses design point to construct control function. For linear systems, the present approach combines with the time-invariant structure reliability theory to get design points by solving the problem of the optimization. For non-linear systems, the paper uses mirror-images method to get design points. Finally the paper gives two examples. The results show the method of this paper to be correct and effective by comparing with the primitive Monte Carlo method.

  11. Markov chain Monte Carlo and importance sampling for multiple targets tracking%马尔可夫链蒙特卡洛重要度采样与多目标跟踪

    Institute of Scientific and Technical Information of China (English)

    龙云利; 徐晖; 安玮

    2011-01-01

    针对强杂波环境下的多目标跟踪问题,提出一种基于马尔可夫链蒙特卡洛重要度采样的跟踪方法.通过马尔可夫链蒙特卡洛实现对联合关联事件的采样,据此计算目标可关联量测数据的边缘关联概率.在联合关联事件求解中利用单目标量测的概率密度进行重要度采样,提高采样效率.马尔可夫链蒙特卡洛重要度采样方法克服了联合概率数据关联中的“组合爆炸”问题,能够在强杂波干扰下较好地实现多目标实时跟踪.通过仿真实验对比分析了算法的跟踪精度和处理的时效性,验证了方法的有效性.%This paper presents an algorithm based on Markov chain Monte Carlo and importance sampling(MCMCIS) for tracking multi-target in a dense environment. The joint associated events are sampled by the Markov chain Monte Carlo and the marginal association probability of the measurement to the target is calculated. The probabilistic density is utilized when sampling the associated events as to improve the efficiency. Although the joint probabilistic data association(JPDA) is NP-hard, the MCMCIS provides the ability to track multi-target timely in a dense environment. The simulation experiments are implemented to analyze the tracking precision and processing time, which shows the effectiveness of the algorithm.

  12. Adaptive measurements of urban runoff quality

    Science.gov (United States)

    Wong, Brandon P.; Kerkez, Branko

    2016-11-01

    An approach to adaptively measure runoff water quality dynamics is introduced, focusing specifically on characterizing the timing and magnitude of urban pollutographs. Rather than relying on a static schedule or flow-weighted sampling, which can miss important water quality dynamics if parameterized inadequately, novel Internet-enabled sensor nodes are used to autonomously adapt their measurement frequency to real-time weather forecasts and hydrologic conditions. This dynamic approach has the potential to significantly improve the use of constrained experimental resources, such as automated grab samplers, which continue to provide a strong alternative to sampling water quality dynamics when in situ sensors are not available. Compared to conventional flow-weighted or time-weighted sampling schemes, which rely on preset thresholds, a major benefit of the approach is the ability to dynamically adapt to features of an underlying hydrologic signal. A 28 km2 urban watershed was studied to characterize concentrations of total suspended solids (TSS) and total phosphorus. Water quality samples were autonomously triggered in response to features in the underlying hydrograph and real-time weather forecasts. The study watershed did not exhibit a strong first flush and intraevent concentration variability was driven by flow acceleration, wherein the largest loadings of TSS and total phosphorus corresponded with the steepest rising limbs of the storm hydrograph. The scalability of the proposed method is discussed in the context of larger sensor network deployments, as well the potential to improving control of urban water quality.

  13. Venous Sampling

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Venous sampling Venous sampling is a diagnostic procedure that uses ... the limitations of venous sampling? What is venous sampling? Venous sampling is a diagnostic procedure that involves ...

  14. Postnatal Cardiovascular Adaptation

    Directory of Open Access Journals (Sweden)

    Ferda Ozlu

    2016-06-01

    Full Text Available Fetus depends on placental circulation in utero. A successful transition from intrauterin to extrauterine life depends on succesful physiological changes during labor. During delivery, fetus transfers from a liquid environment where oxygen comes via umbilical vein to air environement where oxygenation is supported via air breathing. Endocrinological changes are important for fetus to adapt to extrauterine life. In addition to these, cord clemping plays a crucial role in postnatal adaptation. Establishment of neonatal postnatal life and succesful overcome, the fetal cardiovascular transition period are important to stay on. [Archives Medical Review Journal 2016; 25(2.000: 181-190

  15. Adaptive regularization

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Rasmussen, Carl Edward; Svarer, C.

    1994-01-01

    Regularization, e.g., in the form of weight decay, is important for training and optimization of neural network architectures. In this work the authors provide a tool based on asymptotic sampling theory, for iterative estimation of weight decay parameters. The basic idea is to do a gradient descent...... in the estimated generalization error with respect to the regularization parameters. The scheme is implemented in the authors' Designer Net framework for network training and pruning, i.e., is based on the diagonal Hessian approximation. The scheme does not require essential computational overhead in addition...... to what is needed for training and pruning. The viability of the approach is demonstrated in an experiment concerning prediction of the chaotic Mackey-Glass series. The authors find that the optimized weight decays are relatively large for densely connected networks in the initial pruning phase, while...

  16. Adaptive digital filters

    CERN Document Server

    Kovačević, Branko; Milosavljević, Milan

    2013-01-01

    Adaptive Digital Filters” presents an important discipline applied to the domain of speech processing. The book first makes the reader acquainted with the basic terms of filtering and adaptive filtering, before introducing the field of advanced modern algorithms, some of which are contributed by the authors themselves. Working in the field of adaptive signal processing requires the use of complex mathematical tools. The book offers a detailed presentation of the mathematical models that is clear and consistent, an approach that allows everyone with a college level of mathematics knowledge to successfully follow the mathematical derivations and descriptions of algorithms.   The algorithms are presented in flow charts, which facilitates their practical implementation. The book presents many experimental results and treats the aspects of practical application of adaptive filtering in real systems, making it a valuable resource for both undergraduate and graduate students, and for all others interested in m...

  17. Toothbrush Adaptations.

    Science.gov (United States)

    Exceptional Parent, 1987

    1987-01-01

    Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)

  18. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    We investigate why some exchange relationships terminate prematurely. We argue that investments in informal governance structures induce premature termination in relationships already governed by formal contracts. The formalized adaptive behavior of formal governance structures and the flexible a...

  19. Hedonic "adaptation"

    OpenAIRE

    2008-01-01

    People live in a world in which they are surrounded by potential disgust elicitors such as ``used'' chairs, air, silverware, and money as well as excretory activities. People function in this world by ignoring most of these, by active avoidance, reframing, or adaptation. The issue is particularly striking for professions, such as morticians, surgeons, or sanitation workers, in which there is frequent contact with major disgust elicitors. In this study, we study the ``adaptation'' process to d...

  20. Strategic Adaptation

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    2015-01-01

    This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related...... concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation...

  1. Context-aware adaptive spelling in motor imagery BCI

    Science.gov (United States)

    Perdikis, S.; Leeb, R.; Millán, J. d. R.

    2016-06-01

    Objective. This work presents a first motor imagery-based, adaptive brain-computer interface (BCI) speller, which is able to exploit application-derived context for improved, simultaneous classifier adaptation and spelling. Online spelling experiments with ten able-bodied users evaluate the ability of our scheme, first, to alleviate non-stationarity of brain signals for restoring the subject’s performances, second, to guide naive users into BCI control avoiding initial offline BCI calibration and, third, to outperform regular unsupervised adaptation. Approach. Our co-adaptive framework combines the BrainTree speller with smooth-batch linear discriminant analysis adaptation. The latter enjoys contextual assistance through BrainTree’s language model to improve online expectation-maximization maximum-likelihood estimation. Main results. Our results verify the possibility to restore single-sample classification and BCI command accuracy, as well as spelling speed for expert users. Most importantly, context-aware adaptation performs significantly better than its unsupervised equivalent and similar to the supervised one. Although no significant differences are found with respect to the state-of-the-art PMean approach, the proposed algorithm is shown to be advantageous for 30% of the users. Significance. We demonstrate the possibility to circumvent supervised BCI recalibration, saving time without compromising the adaptation quality. On the other hand, we show that this type of classifier adaptation is not as efficient for BCI training purposes.

  2. Is adaptation. Truly an adaptation? Is adaptation. Truly an adaptation?

    Directory of Open Access Journals (Sweden)

    Thais Flores Nogueira Diniz

    2008-04-01

    Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning. The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition

  3. Genomics of local adaptation with gene flow.

    Science.gov (United States)

    Tigano, Anna; Friesen, Vicki L

    2016-05-01

    Gene flow is a fundamental evolutionary force in adaptation that is especially important to understand as humans are rapidly changing both the natural environment and natural levels of gene flow. Theory proposes a multifaceted role for gene flow in adaptation, but it focuses mainly on the disruptive effect that gene flow has on adaptation when selection is not strong enough to prevent the loss of locally adapted alleles. The role of gene flow in adaptation is now better understood due to the recent development of both genomic models of adaptive evolution and genomic techniques, which both point to the importance of genetic architecture in the origin and maintenance of adaptation with gene flow. In this review, we discuss three main topics on the genomics of adaptation with gene flow. First, we investigate selection on migration and gene flow. Second, we discuss the three potential sources of adaptive variation in relation to the role of gene flow in the origin of adaptation. Third, we explain how local adaptation is maintained despite gene flow: we provide a synthesis of recent genomic models of adaptation, discuss the genomic mechanisms and review empirical studies on the genomics of adaptation with gene flow. Despite predictions on the disruptive effect of gene flow in adaptation, an increasing number of studies show that gene flow can promote adaptation, that local adaptations can be maintained despite high gene flow, and that genetic architecture plays a fundamental role in the origin and maintenance of local adaptation with gene flow.

  4. Applying IRT_ΔB Procedure and Adapted LR Procedure to Detect DIF in Tests with Matrix Sampling%IRT_Δb法和修正LR法对矩阵取样DIF检验的有效性

    Institute of Scientific and Technical Information of China (English)

    张勋; 李凌艳; 刘红云; 孙研

    2013-01-01

    Matrix sampling is a useful technique widely used in large-scale educational assessments. In an assessment with matrix sampling design, each examinee takes one of the multiple booklets with partial items. A critical problem of detecting differential item functioning (DIF) in such scenario has gained a lot of attention in recent years, which is, it is not appropriate to take the observed total score obtained from individual booklet as the matching variable in detecting the DIF. Therefore, the traditional detecting methods, such as Mantel-Haenszel (MH), SIBTEST, as well as Logistic Regression (LR) are not suitable. IRT_Δb might be an alternative due to its abilities to provide valid matching variable. However, the DIF classification criterion of IRT_Δb was not well established yet. Thus, the purpose of this study were: 1) to investigate the efficiency and robustness of using ability parameters obtained from Item Response Theory (IRT) model as the matching variable, comparing with the way using traditional observed raw total scores;2) to further identify what factors will influence the abilities in detecting DIF of two methods;3) to propose a DIF classification criteria for IRT_Δb. Simulated and empirical data were both employed in this study to explore the robustness and the efficiency of the two prevailing DIF detecting methods, which were the IRT_Δb method and the adapted LR method with the estimation of group-level ability based on IRT model as the matching variable. In the Monte Carlo study, a matrix sampling test was generated, and various experimental conditions were simulated as follows:1) different proportions of DIF items;2) different actual examinee ability distributions;3) different sample sizes;4) different size of DIF. Two DIF detection methods were then applied and results were compared. In addition, power functions were established in order to derive DIF classification rule for IRT_Δb based on current rules for LR. In the empirical study, through

  5. Adaptive context exploitation

    Science.gov (United States)

    Steinberg, Alan N.; Bowman, Christopher L.

    2013-05-01

    This paper presents concepts and an implementation scheme to improve information exploitation processes and products by adaptive discovery and processing of contextual information. Context is used in data fusion - and in inferencing in general - to provide expectations and to constrain processing. It also is used to infer or refine desired information ("problem variables") on the basis of other available information ("context variables"). Contextual exploitation becomes critical in several classes of inferencing problems in which traditional information sources do not provide sufficient resolution between entity states or when such states are poorly or incompletely modeled. An adaptive evidence-accrual inference method - adapted from developments in target recognition and scene understanding - is presented; whereby context variables are selected on the basis of (a) their utility in refining explicit problem variables, (b) the probability of evaluating these variables to within a given accuracy, given candidate system actions (data collection, mining or processing), and (c) the cost of such actions. The Joint Directors of Laboratories (JDL) Data Fusion Model, with its extension to dual Resource Management functions, has been adapted to accommodate adaptive information exploitation, to include adaptive context exploitation. The interplay of Data Fusion and Resource Management (DF&RM) functionality in exploiting contextual information is illustrated in terms of the dual-node DF&RM architecture. An important advance is in the integration of data mining methods for data search/discovery and for abductive model refinement.

  6. Adaptive metric kernel regression

    DEFF Research Database (Denmark)

    Goutte, Cyril; Larsen, Jan

    2000-01-01

    regression by minimising a cross-validation estimate of the generalisation error. This allows to automatically adjust the importance of different dimensions. The improvement in terms of modelling performance is illustrated on a variable selection task where the adaptive metric kernel clearly outperforms...

  7. Adaptive Metric Kernel Regression

    DEFF Research Database (Denmark)

    Goutte, Cyril; Larsen, Jan

    1998-01-01

    by minimising a cross-validation estimate of the generalisation error. This allows one to automatically adjust the importance of different dimensions. The improvement in terms of modelling performance is illustrated on a variable selection task where the adaptive metric kernel clearly outperforms the standard...

  8. Adapting Bulls to Florida

    Science.gov (United States)

    The adaptation of bulls used for natural breeding purposes to the Gulf Coast region of the United States including all of Florida is an important topic. Nearly 40% of the U.S. cow/calf population resides in the Gulf Coast and Southeast. Thus, as A.I. is relatively rare, the number of bulls used for ...

  9. Image Sampling with Quasicrystals

    CERN Document Server

    Grundland, Mark; Masakova, Zuzana; Dodgson, Neil A; 10.3842/SIGMA.2009.075

    2009-01-01

    We investigate the use of quasicrystals in image sampling. Quasicrystals produce space-filling, non-periodic point sets that are uniformly discrete and relatively dense, thereby ensuring the sample sites are evenly spread out throughout the sampled image. Their self-similar structure can be attractive for creating sampling patterns endowed with a decorative symmetry. We present a brief general overview of the algebraic theory of cut-and-project quasicrystals based on the geometry of the golden ratio. To assess the practical utility of quasicrystal sampling, we evaluate the visual effects of a variety of non-adaptive image sampling strategies on photorealistic image reconstruction and non-photorealistic image rendering used in multiresolution image representations. For computer visualization of point sets used in image sampling, we introduce a mosaic rendering technique.

  10. Image Sampling with Quasicrystals

    Directory of Open Access Journals (Sweden)

    Mark Grundland

    2009-07-01

    Full Text Available We investigate the use of quasicrystals in image sampling. Quasicrystals produce space-filling, non-periodic point sets that are uniformly discrete and relatively dense, thereby ensuring the sample sites are evenly spread out throughout the sampled image. Their self-similar structure can be attractive for creating sampling patterns endowed with a decorative symmetry. We present a brief general overview of the algebraic theory of cut-and-project quasicrystals based on the geometry of the golden ratio. To assess the practical utility of quasicrystal sampling, we evaluate the visual effects of a variety of non-adaptive image sampling strategies on photorealistic image reconstruction and non-photorealistic image rendering used in multiresolution image representations. For computer visualization of point sets used in image sampling, we introduce a mosaic rendering technique.

  11. Adaptive Face Recognition via Structed Representation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-hua; ZENG Xiao-ming

    2014-01-01

    In this paper, we propose a face recognition approach-Structed Sparse Representation-based classification when the measurement of the test sample is less than the number training samples of each subject. When this condition is not satisfied, we exploit Nearest Subspace approach to classify the test sample. In order to adapt all the cases, we combine the two approaches to an adaptive classification method-Adaptive approach. The adaptive approach yields greater recognition accuracy than the SRC approach and CRC_RLS approach with low sample rate on the Extend Yale B dataset. And it is more efficient than other two approaches.

  12. Adaptive test

    DEFF Research Database (Denmark)

    Kjeldsen, Lars Peter; Rose, Mette

    2010-01-01

    Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale.......Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale....

  13. Procedures for Sampling Vegetation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines vegetation sampling procedures used on various refuges in Region 3. The importance of sampling the response of marsh vegetation to management...

  14. Intestinal mucosal adaptation

    Institute of Scientific and Technical Information of China (English)

    Laurie Drozdowski; Alan BR Thomson

    2006-01-01

    Intestinal failure is a condition characterized by malnutrition and/or dehydration as a result of the inadequate digestion and absorption of nutrients. The most common cause of intestinal failure is short bowel syndrome, which occurs when the functional gut mass is reduced below the level necessary for adequate nutrient and water absorption. This condition may be congenital, or may be acquired as a result of a massive resection of the small bowel. Following resection, the intestine is capable of adaptation in response to enteral nutrients as well as other trophic stimuli. Identifying factors that may enhance the process of intestinal adaptation is an exciting area of research with important potential clinical applications.

  15. STUDYING COMPLEX ADAPTIVE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    John H. Holland

    2006-01-01

    Complex adaptive systems (cas) - systems that involve many components that adapt or learn as they interact - are at the heart of important contemporary problems. The study of cas poses unique challenges: Some of our most powerful mathematical tools, particularly methods involving fixed points, attractors, and the like, are of limited help in understanding the development of cas. This paper suggests ways to modify research methods and tools, with an emphasis on the role of computer-based models, to increase our understanding of cas.

  16. Adaptive Playware in Physical Games

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop; Thorsteinsson, Arnar Tumi

    2011-01-01

    that the activity automatically will match the capability of the individual user. With small test groups, we investigate how different age groups and gender groups physically interact with some playware games, and find indications of differences between the groups. Despite the small test set, the results......We describe how playware and games may adapt to the interaction of the individual user. We hypothesize that in physical games there are individual differences in user interaction capabilities and styles, and that adaptive playware may adapt to the individual user’s capabilities, so...... are a proof of existence of differences and of the need for adaptation, and therefore we investigate adaptation as an important issue for playware. With simple playware games, we show that the adaptation will speed the physical game up and down to find the appropriate level that matches the reaction speed...

  17. Hedonic "adaptation"

    Directory of Open Access Journals (Sweden)

    Paul Rozin

    2008-02-01

    Full Text Available People live in a world in which they are surrounded by potential disgust elicitors such as ``used'' chairs, air, silverware, and money as well as excretory activities. People function in this world by ignoring most of these, by active avoidance, reframing, or adaptation. The issue is particularly striking for professions, such as morticians, surgeons, or sanitation workers, in which there is frequent contact with major disgust elicitors. In this study, we study the ``adaptation'' process to dead bodies as disgust elicitors, by measuring specific types of disgust sensitivity in medical students before and after they have spent a few months dissecting a cadaver. Using the Disgust Scale, we find a significant reduction in disgust responses to death and body envelope violation elicitors, but no significant change in any other specific type of disgust. There is a clear reduction in discomfort at touching a cold dead body, but not in touching a human body which is still warm after death.

  18. Adaptation Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Huq, Saleemul

    2011-11-15

    Efforts to help the world's poor will face crises in coming decades as climate change radically alters conditions. Action Research for Community Adapation in Bangladesh (ARCAB) is an action-research programme on responding to climate change impacts through community-based adaptation. Set in Bangladesh at 20 sites that are vulnerable to floods, droughts, cyclones and sea level rise, ARCAB will follow impacts and adaptation as they evolve over half a century or more. National and international 'research partners', collaborating with ten NGO 'action partners' with global reach, seek knowledge and solutions applicable worldwide. After a year setting up ARCAB, we share lessons on the programme's design and move into our first research cycle.

  19. Sample Design.

    Science.gov (United States)

    Ross, Kenneth N.

    1987-01-01

    This article considers various kinds of probability and non-probability samples in both experimental and survey studies. Throughout, how a sample is chosen is stressed. Size alone is not the determining consideration in sample selection. Good samples do not occur by accident; they are the result of a careful design. (Author/JAZ)

  20. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  1. What Drives Business Model Adaptation?

    DEFF Research Database (Denmark)

    Saebi, Tina; Lien, Lasse B.; Foss, Nicolai Juul

    2016-01-01

    Business models change as managers not only innovate business models, but also engage in more mundane adaptation in response to external changes, such as changes in the level or composition of demand. However, little is known about what causes such business model adaptation. We employ threat......-rigidity as well as prospect theory to examine business model adaptation in response to external threats and opportunities. Additionally, drawing on the behavioural theory of the firm, we argue that the past strategic orientation of a firm creates path dependencies that influence the propensity of the firm...... to adapt its business model. We test our hypotheses on a sample of 1196 Norwegian companies, and find that firms are more likely to adapt their business model under conditions of perceived threats than opportunities, and that strategic orientation geared towards market development is more conducive...

  2. Biological sample collector

    Science.gov (United States)

    Murphy, Gloria A.

    2010-09-07

    A biological sample collector is adapted to a collect several biological samples in a plurality of filter wells. A biological sample collector may comprise a manifold plate for mounting a filter plate thereon, the filter plate having a plurality of filter wells therein; a hollow slider for engaging and positioning a tube that slides therethrough; and a slide case within which the hollow slider travels to allow the tube to be aligned with a selected filter well of the plurality of filter wells, wherein when the tube is aligned with the selected filter well, the tube is pushed through the hollow slider and into the selected filter well to sealingly engage the selected filter well and to allow the tube to deposit a biological sample onto a filter in the bottom of the selected filter well. The biological sample collector may be portable.

  3. The Adaptation Gap Report - a Preliminary Assessment

    DEFF Research Database (Denmark)

    Alverson, Keith; Olhoff, Anne; Noble, Ian;

    This first Adaptation Gap report provides an equally sobering assessment of the gap between adaptation needs and reality, based on preliminary thinking on how baselines, future goals or targets, and gaps between them might be defined for climate change adaptation. The report focuses on gaps in de...... in developing countries in three important areas: finance, technology and knowledge....

  4. Capillary sample

    Science.gov (United States)

    ... several times a day using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a limited ... do not constitute endorsements of those other sites. Copyright 1997-2017, A.D.A.M., Inc. Duplication ...

  5. New competitive dendrimer-based and highly selective immunosensor for determination of atrazine in environmental, feed and food samples: the importance of antibody selectivity for discrimination among related triazinic metabolites.

    Science.gov (United States)

    Giannetto, Marco; Umiltà, Eleonora; Careri, Maria

    2014-01-01

    A new voltammetric competitive immunosensor selective for atrazine, based on the immobilization of a conjugate atrazine-bovine serum albumine on a nanostructured gold substrate previously functionalized with poliamidoaminic dendrimers, was realized, characterized, and validated in different real samples of environmental and food concern. Response of the sensor was reliable, highly selective and suitable for the detection and quantification of atrazine at trace levels in complex matrices such as territorial waters, corn-cultivated soils, corn-containing poultry and bovine feeds and corn flakes for human use. Selectivity studies were focused on desethylatrazine, the principal metabolite generated by long-term microbiological degradation of atrazine, terbutylazine-2-hydroxy and simazine as potential interferents. The response of the developed immunosensor for atrazine was explored over the 10(-2)-10(3) ng mL(-1) range. Good sensitivity was proved, as limit of detection and limit of quantitation of 1.2 and 5 ng mL(-1), respectively, were estimated for atrazine. RSD values <5% over the entire explored range attested a good precision of the device.

  6. Genetic structure of different cat populations in Europe and South America at a microgeographic level: importance of the choice of an adequate sampling level in the accuracy of population genetics interpretations

    Directory of Open Access Journals (Sweden)

    Manuel Ruiz-Garcia

    1999-12-01

    Full Text Available The phenotypic markers, coat color, pattern and hair length, of natural domestic cat populations observed in four cities (Barcelona, Catalonia; Palma Majorca, Balearic Islands; Rimini, Italy and Buenos Aires, Argentina were studied at a microgeographical level. Various population genetics techniques revealed that the degree of genetic differentiation between populations of Felis catus within these cities is relatively low, when compared with that found between populations of other mammals. Two different levels of sampling were used. One was that of "natural" colonies of cat families living together in specific points within the cities, and the other referred to "artificial" subpopulations, or groups of colonies, inhabiting the same district within a city. For the two sampling levels, some of the results were identical: 1 little genic heterogeneity, 2 existence of panmixia, 3 similar levels of expected heterozygosity in all populations analyzed, 4 no spatial autocorrelation, with certain differentiation in the Buenos Aires population compared to the others, and 5 very high correlations between colonies and subpopulations with the first factors from a Q factor analysis. Nevertheless, other population genetic statistics were greatly affected by the differential choice of sampling level. This was the case for: 1 the amount of heterogeneity of the FST and GST statistics between the cities, which was greater at the subpopulation level than at colony level, 2 the existence of correlations between genic differentiation statistics and size variables at subpopulation level, but not at the colony level, and 3 the relationships between the genetic variables and the principal factors of the R factorial analysis. This suggests that care should be taken in the choice of the sampling unit, for inferences on population genetics to be valid at the microgeographical level.Os marcadores fenotípicos cor da pelagem, padrão e comprimento dos pelos de popula

  7. Multi-Directional Motion Adaptation

    Directory of Open Access Journals (Sweden)

    David Patrick McGovern

    2012-05-01

    Full Text Available The direction aftereffect (DAE is a phenomenon whereby prolonged exposure to a moving stimulus biases the perceived direction of subsequent stimuli. It is believed to arise through a selective suppression of directionally tuned neurons in the visual cortex, causing shifts in the population response away from the adapted direction. Whereas most studies consider only unidirectional adaptation, here we examine how concurrent adaptation to multiple directions affects the DAE. Observers were required to judge whether a random dot kinematogram (RDK moved clockwise or counter-clockwise relative to upwards. In different conditions, observers adapted to a stimulus comprised of directions drawn from a distribution or to bidirectional motion. Increasing the variance of normally distributed directions reduced the magnitude of the peak DAE and broadened its tuning profile. Asymmetric sampling of Gaussian and uniform distributions resulted in shifts of DAE tuning profiles consistent with changes in the perceived global direction of the adapting stimulus. Discrimination thresholds were elevated by an amount that related to the magnitude of the bias. For bidirectional adaptors, adding dots in directions away from the adapting motion led to a pronounced reduction in the DAE. This reduction was observed when dots were added in opposite or orthogonal directions to the adaptor suggesting that it may arise via inhibition from a broadly tuned normalisation pool. Preliminary simulations with a population coding model, where the gain of a direction-selective neuron is inversely proportional to its response to the adapting stimulus, suggest that it provides a parsimonious account of these adaptation effects.

  8. Adaptive manifold learning.

    Science.gov (United States)

    Zhang, Zhenyue; Wang, Jing; Zha, Hongyuan

    2012-02-01

    Manifold learning algorithms seek to find a low-dimensional parameterization of high-dimensional data. They heavily rely on the notion of what can be considered as local, how accurately the manifold can be approximated locally, and, last but not least, how the local structures can be patched together to produce the global parameterization. In this paper, we develop algorithms that address two key issues in manifold learning: 1) the adaptive selection of the local neighborhood sizes when imposing a connectivity structure on the given set of high-dimensional data points and 2) the adaptive bias reduction in the local low-dimensional embedding by accounting for the variations in the curvature of the manifold as well as its interplay with the sampling density of the data set. We demonstrate the effectiveness of our methods for improving the performance of manifold learning algorithms using both synthetic and real-world data sets.

  9. GLOBALIZATION AND IMPORT RISKS

    Directory of Open Access Journals (Sweden)

    Popa Ioan

    2014-07-01

    Full Text Available Delocalization of production and diversification of the sources of offer in the global market place the issue of protection of consumer rights in major consumption centres, namely the European Union in a new light. A review of policies for the protection of consumer rights in the EU, USA and China, reveals major differences regarding the protection of consumer rights and the existence of gaps, and in particular the implementation of effective legislation in this regard. As such, the risks associated with imports have become a major concern in the European Union. The consumer has – one can say – a central role in the globalization process, which justifies the measures aimed at its protection. Although worldwide there are major differences in the degree of market regulation in matters of protection of consumer rights, the trend is the continuous adaptation of the offer to the requirements of global demand. However, one can still find significant gaps which translate into risks specific to the consumers in developed countries, namely in the EU. An important issue arises from this radical change of the localization of production centres in relation to the main consumption centres. While in the developed world, consumer rights protection has reached high levels both by creating an appropriate legislative framework and through consumer awareness and activism regarding their rights, in areas where much of the offer comes from the Western market (China, India, etc. modern mentality on the protection of consumer rights is just emerging. A major requirement is therefore the provision of a status of the consumer compatible with the benefits and risks of globalization, a status defined by safety and protection of imports. This paper confirms the thesis that, ultimately, the main factor counteracting the risks in matters of protection of consumer rights is the consumer, its awareness of its rights.

  10. Adaptive management

    DEFF Research Database (Denmark)

    Rist, Lucy; Campbell, Bruce Morgan; Frost, Peter

    2013-01-01

    in scientific articles, policy documents and management plans, but both understanding and application of the concept is mixed. This paper reviews recent literature from conservation and natural resource management journals to assess diversity in how the term is used, highlight ambiguities and consider how...... the concept might be further assessed. AM is currently being used to describe many different management contexts, scales and locations. Few authors define the term explicitly or describe how it offers a means to improve management outcomes in their specific management context. Many do not adhere to the idea......Adaptive management (AM) emerged in the literature in the mid-1970s in response both to a realization of the extent of uncertainty involved in management, and a frustration with attempts to use modelling to integrate knowledge and make predictions. The term has since become increasingly widely used...

  11. Sequencing of 50 human exomes reveals adaptation to high altitude

    DEFF Research Database (Denmark)

    Yi, Xin; Liang, Yu; Huerta-Sanchez, Emilia;

    2010-01-01

    Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which...... represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia. One single-nucleotide polymorphism (SNP) at EPAS1 shows a 78% frequency...... difference between Tibetan and Han samples, representing the fastest allele frequency change observed at any human gene to date. This SNP's association with erythrocyte abundance supports the role of EPAS1 in adaptation to hypoxia. Thus, a population genomic survey has revealed a functionally important locus...

  12. Kinetic Solvers with Adaptive Mesh in Phase Space

    CERN Document Server

    Arslanbekov, Robert R; Frolova, Anna A

    2013-01-01

    An Adaptive Mesh in Phase Space (AMPS) methodology has been developed for solving multi-dimensional kinetic equations by the discrete velocity method. A Cartesian mesh for both configuration (r) and velocity (v) spaces is produced using a tree of trees data structure. The mesh in r-space is automatically generated around embedded boundaries and dynamically adapted to local solution properties. The mesh in v-space is created on-the-fly for each cell in r-space. Mappings between neighboring v-space trees implemented for the advection operator in configuration space. We have developed new algorithms for solving the full Boltzmann and linear Boltzmann equations with AMPS. Several recent innovations were used to calculate the full Boltzmann collision integral with dynamically adaptive mesh in velocity space: importance sampling, multi-point projection method, and the variance reduction method. We have developed an efficient algorithm for calculating the linear Boltzmann collision integral for elastic and inelastic...

  13. Maternal Identity Formation in a Military Sample: A Longitudinal Perspective

    Science.gov (United States)

    2006-06-08

    sample comprised 20 high-risk primiparous adolescents. The theoretical framework for the project was based on maternal role theory. Importantly, the... primiparous mothers. The British Journal of Psychiatry, 146, 287- 293. Barnett, R. C. (2004). Women and multiple roles: Myths and reality. Harvard Review... primiparous women. Maternal Child Nursing Journal, 23, 90-100. Hamburg, D. A., Coelho, G. V., & Adams, J. E. (1974). Coping and adaptation: Steps

  14. Adaptive vehicle motion estimation and prediction

    Science.gov (United States)

    Zhao, Liang; Thorpe, Chuck E.

    1999-01-01

    Accurate motion estimation and reliable maneuver prediction enable an automated car to react quickly and correctly to the rapid maneuvers of the other vehicles, and so allow safe and efficient navigation. In this paper, we present a car tracking system which provides motion estimation, maneuver prediction and detection of the tracked car. The three strategies employed - adaptive motion modeling, adaptive data sampling, and adaptive model switching probabilities - result in an adaptive interacting multiple model algorithm (AIMM). The experimental results on simulated and real data demonstrate that our tracking system is reliable, flexible, and robust. The adaptive tracking makes the system intelligent and useful in various autonomous driving tasks.

  15. Language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik

    1998-01-01

    This article has two aims: [1] to present a revised version of the sampling method that was originally proposed in 1993 by Rijkhoff, Bakker, Hengeveld and Kahrel, and [2] to discuss a number of other approaches to language sampling in the light of our own method. We will also demonstrate how our...... sampling method is used with different genetic classifications (Voegelin & Voegelin 1977, Ruhlen 1987, Grimes ed. 1997) and argue that —on the whole— our sampling technique compares favourably with other methods, especially in the case of exploratory research....

  16. Social Importance Dynamics: A Model for Culturally-Adaptive Agents

    NARCIS (Netherlands)

    Mascarenhas, S.; Prada, R.; Paiva, A.; Hofstede, G.J.

    2013-01-01

    The unwritten rules of human cultures greatly affect social behaviour and as such should be considered in the development of socially intelligent agents. So far, there has been a large focus on modeling cultural aspects related to non-verbal behaviour such as gaze or body posture. However, culture a

  17. Taking Root in Foreign Soil: Adaptation Processes of Imported Universities

    Science.gov (United States)

    Graham, Terrece F.

    2016-01-01

    The fall of the Berlin Wall in 1989 ushered in a period of change in higher-education systems across the former Eastern bloc. Reform-minded leaders in the region sought to introduce western models and policies promoted by foreign development aid agendas. Private higher-education institutions emerged. This qualitative multiple case study examines…

  18. El Cuestionario de Necesidades de los Familiares de Pacientes de Cuidados Intensivos (CCFNI versión breve: adaptación y validación en población española The short version of Critical Care Family Needs Inventory (CCFNI: adaptation and validation for a Spanish sample

    Directory of Open Access Journals (Sweden)

    S. Gómez Martínez

    2011-12-01

    Full Text Available Los familiares son una parte muy importante en el proceso de la enfermedad y el cuidado de los pacientes ingresados en Unidades de Cuidados Intensivos (UCI. Por ello es fundamental conocer sus necesidades, para tratar de mejorar la adaptación a una situación tan difícil como es el ingreso en UCI. El objetivo del presente estudio es adaptar y validar la versión breve del Cuestionario de Necesidades de los Familiares de Pacientes de Cuidados Intensivos (CCFNI en una muestra española. Para ello se aplicó la adaptación del cuestionario, realizada conforme a las directrices internacionales, a 55 familiares de pacientes ingresados en la UCI del Hospital General Universitario de Castellón. Tras la eliminación de tres ítems por diversos motivos, se realizó un análisis factorial exploratorio con los 11 ítems restantes para obtener la estructura factorial del mismo. Se realizó un análisis descriptivo de los ítems y se calcularon la consistencia interna mediante α de Cronbach y la validez de constructo mediante el coeficiente de correlación de Pearson. El CCFNI obtuvo una estructura de cuatro factores que corresponden a: atención médica al paciente, atención personal al familiar, información y comunicación médico-paciente y posibles mejoras percibidas. Esta versión del CCFNI mostró una buena consistencia interna tanto para la escala total como para los factores. La versión del CCFNI validada en el presente estudio constituye una medida adecuada para la evaluación de las distintas necesidades que presentan los familiares de los pacientes ingresados en una UCI, mostrando una adecuada bondad psicométrica.Relatives play an important role in the disease process of patients admitted to Intensive Care Units (ICU. It is therefore important to know the needs of people close to the patient in order to try to improve their adaption to a situation as difficult as an ICU admission. The aim of this study was the adaptation and validation of

  19. Adaptive method of lines

    CERN Document Server

    Saucez, Ph

    2001-01-01

    The general Method of Lines (MOL) procedure provides a flexible format for the solution of all the major classes of partial differential equations (PDEs) and is particularly well suited to evolutionary, nonlinear wave PDEs. Despite its utility, however, there are relatively few texts that explore it at a more advanced level and reflect the method''s current state of development.Written by distinguished researchers in the field, Adaptive Method of Lines reflects the diversity of techniques and applications related to the MOL. Most of its chapters focus on a particular application but also provide a discussion of underlying philosophy and technique. Particular attention is paid to the concept of both temporal and spatial adaptivity in solving time-dependent PDEs. Many important ideas and methods are introduced, including moving grids and grid refinement, static and dynamic gridding, the equidistribution principle and the concept of a monitor function, the minimization of a functional, and the moving finite elem...

  20. Sampling Development

    Science.gov (United States)

    Adolph, Karen E.; Robinson, Scott R.

    2011-01-01

    Research in developmental psychology requires sampling at different time points. Accurate depictions of developmental change provide a foundation for further empirical studies and theories about developmental mechanisms. However, overreliance on widely spaced sampling intervals in cross-sectional and longitudinal designs threatens the validity of…

  1. Adaptation-Based Programming in Haskell

    CERN Document Server

    Bauer, Tim; Fern, Alan; Pinto, Jervis; 10.4204/EPTCS.66.1

    2011-01-01

    We present an embedded DSL to support adaptation-based programming (ABP) in Haskell. ABP is an abstract model for defining adaptive values, called adaptives, which adapt in response to some associated feedback. We show how our design choices in Haskell motivate higher-level combinators and constructs and help us derive more complicated compositional adaptives. We also show an important specialization of ABP is in support of reinforcement learning constructs, which optimize adaptive values based on a programmer-specified objective function. This permits ABP users to easily define adaptive values that express uncertainty anywhere in their programs. Over repeated executions, these adaptive values adjust to more efficient ones and enable the user's programs to self optimize. The design of our DSL depends significantly on the use of type classes. We will illustrate, along with presenting our DSL, how the use of type classes can support the gradual evolution of DSLs.

  2. Adaptation-Based Programming in Haskell

    Directory of Open Access Journals (Sweden)

    Tim Bauer

    2011-09-01

    Full Text Available We present an embedded DSL to support adaptation-based programming (ABP in Haskell. ABP is an abstract model for defining adaptive values, called adaptives, which adapt in response to some associated feedback. We show how our design choices in Haskell motivate higher-level combinators and constructs and help us derive more complicated compositional adaptives. We also show an important specialization of ABP is in support of reinforcement learning constructs, which optimize adaptive values based on a programmer-specified objective function. This permits ABP users to easily define adaptive values that express uncertainty anywhere in their programs. Over repeated executions, these adaptive values adjust to more efficient ones and enable the user's programs to self optimize. The design of our DSL depends significantly on the use of type classes. We will illustrate, along with presenting our DSL, how the use of type classes can support the gradual evolution of DSLs.

  3. Soil sampling kit and a method of sampling therewith

    Science.gov (United States)

    Thompson, Cyril V.

    1991-01-01

    A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allow an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds.

  4. Efficiency and accuracy of Monte Carlo (importance) sampling

    NARCIS (Netherlands)

    Waarts, P.H.

    2003-01-01

    Monte Carlo Analysis is often regarded as the most simple and accurate reliability method. Be-sides it is the most transparent method. The only problem is the accuracy in correlation with the efficiency. Monte Carlo gets less efficient or less accurate when very low probabilities are to be computed

  5. Performance evaluation of communication systems via importance sampling

    NARCIS (Netherlands)

    Remondo Bueno, D.

    2000-01-01

    In the design and development of telecommunication systems, the preparation of experiments can be made more effective by predicting the system performance and its dependence on the different system parameters. This can be done by modeling the system and using performance evaluation methods. This dis

  6. On Adaptive Optimal Input Design

    NARCIS (Netherlands)

    Stigter, J.D.; Vries, D.; Keesman, K.J.

    2003-01-01

    The problem of optimal input design (OID) for a fed-batch bioreactor case study is solved recursively. Here an adaptive receding horizon optimal control problem, involving the so-called E-criterion, is solved on-line, using the current estimate of the parameter vector at each sample instant {tk, k =

  7. Economics of adaptation to climate change; Economie de l'adaptation au changement climatique

    Energy Technology Data Exchange (ETDEWEB)

    Perthuis, Ch.; Hallegatte, St.; Lecocq, F.

    2010-02-15

    This report proposes a general economic framework for the issue of adaptation to climate change in order to help public and private actors to build up efficient adaptation strategies. It proposes a general definition of adaptation, identifies the major stakes for these strategies, and discusses the assessment of global costs of adaptation to climate change. It discusses the role and modalities of public action and gives some examples of possible adaptation measures in some important sectors (building and town planning, energy and transport infrastructures, water and agriculture, ecosystems, insurance). It examines the regional and national dimensions of adaptation and their relationship, and defines steps for implementing an adaptation strategy. It describes and discusses the use of economic tools in the elaboration of an adaptation strategy, i.e. how to take uncertainties into account, which scenarios to choose, how to use economic calculations to assess adaptation policies

  8. The Lunar Sample Compendium

    Science.gov (United States)

    Meyer, Charles

    2009-01-01

    The Lunar Sample Compendium is a succinct summary of the data obtained from 40 years of study of Apollo and Luna samples of the Moon. Basic petrographic, chemical and age information is compiled, sample-by-sample, in the form of an advanced catalog in order to provide a basic description of each sample. The LSC can be found online using Google. The initial allocation of lunar samples was done sparingly, because it was realized that scientific techniques would improve over the years and new questions would be formulated. The LSC is important because it enables scientists to select samples within the context of the work that has already been done and facilitates better review of proposed allocations. It also provides back up material for public displays, captures information found only in abstracts, grey literature and curatorial databases and serves as a ready access to the now-vast scientific literature.

  9. Adaptively robust filtering with classified adaptive factors

    Institute of Scientific and Technical Information of China (English)

    CUI Xianqiang; YANG Yuanxi

    2006-01-01

    The key problems in applying the adaptively robust filtering to navigation are to establish an equivalent weight matrix for the measurements and a suitable adaptive factor for balancing the contributions of the measurements and the predicted state information to the state parameter estimates. In this paper, an adaptively robust filtering with classified adaptive factors was proposed, based on the principles of the adaptively robust filtering and bi-factor robust estimation for correlated observations. According to the constant velocity model of Kalman filtering, the state parameter vector was divided into two groups, namely position and velocity. The estimator of the adaptively robust filtering with classified adaptive factors was derived, and the calculation expressions of the classified adaptive factors were presented. Test results show that the adaptively robust filtering with classified adaptive factors is not only robust in controlling the measurement outliers and the kinematic state disturbing but also reasonable in balancing the contributions of the predicted position and velocity, respectively, and its filtering accuracy is superior to the adaptively robust filter with single adaptive factor based on the discrepancy of the predicted position or the predicted velocity.

  10. Local adaptation in brown trout early life-history traits: implications for climate change adaptability

    DEFF Research Database (Denmark)

    Jensen, L.F.; Hansen, Michael Møller; Pertoldi, C.

    2008-01-01

    to adapt. Temperature-related adaptability in traits related to phenology and early life history are expected to be particularly important in salmonid fishes. We focused on the latter and investigated whether four populations of brown trout (Salmo trutta) are locally adapted in early life-history traits...... and heritable variation in phenotypic plasticity suggest that although increasing temperatures are likely to affect some populations negatively, they may have the potential to adapt to changing temperature regimes.  ...

  11. Personalized Adaptive Learning

    NARCIS (Netherlands)

    Kravcik, Milos; Specht, Marcus; Naeve, Ambjorn

    2009-01-01

    Kravcik, M., Specht, M., & Naeve, A. (2008). Personalized Adaptive Learning. Presentation of PROLEARN WP1 Personalized Adaptive Learning at the final review meeting. February, 27, 2008, Hannover, Germany.

  12. Sample size methodology

    CERN Document Server

    Desu, M M

    2012-01-01

    One of the most important problems in designing an experiment or a survey is sample size determination and this book presents the currently available methodology. It includes both random sampling from standard probability distributions and from finite populations. Also discussed is sample size determination for estimating parameters in a Bayesian setting by considering the posterior distribution of the parameter and specifying the necessary requirements. The determination of the sample size is considered for ranking and selection problems as well as for the design of clinical trials. Appropria

  13. Work sampling

    OpenAIRE

    Salas Bacalla, julio; FII-UNMSM

    2014-01-01

    Work sampling is a method of indirect measurement, which means instantaneous observations, to determine the amount of uptime or downtime in a production process El muestreo de trabajo es un método de medición indirecto, que mediante observaciones instantaneas, permite determinar la cantidad de tiempo en actividad o inactividad en un proceso productivo

  14. A method of language sampling

    DEFF Research Database (Denmark)

    Rijkhoff, Jan; Bakker, Dik; Hengeveld, Kees

    1993-01-01

    In recent years more attention is paid to the quality of language samples in typological work. Without an adequate sampling strategy, samples may suffer from various kinds of bias. In this article we propose a sampling method in which the genetic criterion is taken as the most important: samples...... to determine how many languages from each phylum should be selected, given any required sample size....

  15. Reverse transcription polymerase chain reaction (RT-PCR based detection and serotyping of FMD Virus from field samples of Gazipur, Bangladesh, and adaptation of the virus in BHK-21 cell

    Directory of Open Access Journals (Sweden)

    Mohammad Ashraful Alam

    2015-09-01

    Full Text Available The study aimed for the detection and serotyping of Foot and Mouth Disease virus (FMDV circulating in Kapasia Upazila, Gazipur district of Bangladesh during 2013. Twelve samples comprising of tongue epithelium (n=8 and inter digital tissue (n=4 were collected from suspected cattle, and inocula were prepared. The inocula were inoculated into confluent BHK-21 cell line for virus propagation. After 3 subsequent passages; progressive cytopathic effects (CPE specific for FMDV i.e., rounding and flattening of cells, breaking down of the intercellular bridge and finally cell death (almost 100% were observed; these were indicative of successful virus propagation in the cells. Viral RNA was extracted, and Reverse Transcription Polymerase Chain Reaction (RT-PCR was performed using three sets of primers corresponding to the serotype and lsquo;O', and lsquo;Asia-1' and and lsquo;A', respectively. Out of the 12 samples, 10 (83.33% were found to be positive for FMDV, and all of those were of serotype and lsquo;O'. It is concluded that FMDV serotype and lsquo;O' is circulating among the cattle of Gazipur district, Bangladesh. [J Adv Vet Anim Res 2015; 2(3.000: 291-295

  16. Adaptation and creativity in cultural context

    Directory of Open Access Journals (Sweden)

    Leonora M. Cohen

    2012-06-01

    Full Text Available Adaptation is the fit between the individual and the environment. The dynamic interplay between person, culture, and environment is one of the most important issues in analyzing creativity. Adaptation is defined as the fit or adjustment of the individual to external conditions, but adaptation can also mean moving from one environment to another more suitable, or even forcing the environment to adapt in response to creative efforts. Culture impacts creativity in limiting acceptable boundaries, yet providing the artifacts used in creating. Culture is impacted and changed by creative efforts. Tight conformity to confining environments or cultures can stifle. The creator must be aware of cultural values and not overstep these boundaries for work to be accepted. A developmental continuum of adaptive, creative behaviors suggests a shift from individual adaptation to the environment to adaptation by the world to the individual.

  17. Association of Adaptive and Maladaptive Narcissism with Personal Burnout: findings from a cross-sectional study.

    Science.gov (United States)

    Känel, Roland VON; Herr, Raphael M; Vianen, Annelies E M VAN; Schmidt, Burkhard

    2017-01-25

    Burnout is associated with poor mental and physical functioning and high costs for societies. Personality attributes may critically increase the risk of personal burnout. We specifically examined whether narcissism associates with personal burnout in a working population. We studied n=1461employees (mean age 41.3±9.4 years, 52% men) drawn from a random sample of a pharmaceutical company in Germany. All participants completed the personal burnout subscale of the Copenhagen Burnout Inventory and the Narcissistic Personality Inventory to assess maladaptive (entitlement/exploitativeness) and adaptive (leadership/authority) narcissism. In linear regression analysis, when mutually adjusting for the maladaptive and adaptive narcissism scales, higher adaptive narcissism was associated with lower burnout scores (ß=-0.04, pvalues personality attributes may play an important role in personal burnout. While maladaptive narcissism was associated with increased levels of burnout symptoms, adaptive narcissism was associated with fewer burnout symptoms.

  18. Bayesian analysis for exponential random graph models using the adaptive exchange sampler

    KAUST Repository

    Jin, Ick Hoon

    2013-01-01

    Exponential random graph models have been widely used in social network analysis. However, these models are extremely difficult to handle from a statistical viewpoint, because of the existence of intractable normalizing constants. In this paper, we consider a fully Bayesian analysis for exponential random graph models using the adaptive exchange sampler, which solves the issue of intractable normalizing constants encountered in Markov chain Monte Carlo (MCMC) simulations. The adaptive exchange sampler can be viewed as a MCMC extension of the exchange algorithm, and it generates auxiliary networks via an importance sampling procedure from an auxiliary Markov chain running in parallel. The convergence of this algorithm is established under mild conditions. The adaptive exchange sampler is illustrated using a few social networks, including the Florentine business network, molecule synthetic network, and dolphins network. The results indicate that the adaptive exchange algorithm can produce more accurate estimates than approximate exchange algorithms, while maintaining the same computational efficiency.

  19. Sampling Strategy

    Science.gov (United States)

    2008-01-01

    Three locations to the right of the test dig area are identified for the first samples to be delivered to the Thermal and Evolved Gas Analyzer (TEGA), the Wet Chemistry Lab (WCL), and the Optical Microscope (OM) on NASA's Phoenix Mars Lander. These sampling areas are informally labeled 'Baby Bear', 'Mama Bear', and 'Papa Bear' respectively. This image was taken on the seventh day of the Mars mission, or Sol 7 (June 1, 2008) by the Surface Stereo Imager aboard NASA's Phoenix Mars Lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  20. Candida albicans: adapting to succeed.

    Science.gov (United States)

    Kadosh, David; Lopez-Ribot, Jose L

    2013-11-13

    In this issue of Cell Host & Microbe, Lu et al. (2013) report on the redundancy of signaling pathways controlling Candida albicans filamentation and pathogenicity. In the process, they provide important insight into how this normal commensal of humans adapts to different host microenvironments to become a highly successful opportunistic pathogen.

  1. Adaptive Robust Variable Selection

    CERN Document Server

    Fan, Jianqing; Barut, Emre

    2012-01-01

    Heavy-tailed high-dimensional data are commonly encountered in various scientific fields and pose great challenges to modern statistical analysis. A natural procedure to address this problem is to use penalized least absolute deviation (LAD) method with weighted $L_1$-penalty, called weighted robust Lasso (WR-Lasso), in which weights are introduced to ameliorate the bias problem induced by the $L_1$-penalty. In the ultra-high dimensional setting, where the dimensionality can grow exponentially with the sample size, we investigate the model selection oracle property and establish the asymptotic normality of the WR-Lasso. We show that only mild conditions on the model error distribution are needed. Our theoretical results also reveal that adaptive choice of the weight vector is essential for the WR-Lasso to enjoy these nice asymptotic properties. To make the WR-Lasso practically feasible, we propose a two-step procedure, called adaptive robust Lasso (AR-Lasso), in which the weight vector in the second step is c...

  2. Systems and methods for self-synchronized digital sampling

    Science.gov (United States)

    Samson, Jr., John R. (Inventor)

    2008-01-01

    Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.

  3. A Bio-Inspired Robust Adaptive Random Search Algorithm for Distributed Beamforming

    CERN Document Server

    Tseng, Chia-Shiang; Lin, Che

    2010-01-01

    A bio-inspired robust adaptive random search algorithm (BioRARSA), designed for distributed beamforming for sensor and relay networks, is proposed in this work. It has been shown via a systematic framework that BioRARSA converges in probability and its convergence time scales linearly with the number of distributed transmitters. More importantly, extensive simulation results demonstrate that the proposed BioRARSA outperforms existing adaptive distributed beamforming schemes by as large as 29.8% on average. This increase in performance results from the fact that BioRARSA can adaptively adjust its sampling stepsize via the "swim" behavior inspired by the bacterial foraging mechanism. Hence, the convergence time of BioRARSA is insensitive to the initial sampling stepsize of the algorithm, which makes it robust against the dynamic nature of distributed wireless networks.

  4. Motion Tracking with Fast Adaptive Background Subtraction

    Institute of Scientific and Technical Information of China (English)

    Xiao; De-Gui; Yu; Sheng-sheng; 等

    2003-01-01

    To extract and track moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction algorithm and the motion tracking process using this algorithm. The algorithm uses only luminance components of sampled image sequence pixels and models every pixel in a statistical model.The algorithm is characterized by its ability of real time detecting sudden lighting changes, and extracting and tracking motion objects faster. It is shown that our algorithm can be realized with lower time and space complexity and adjustable object detection error rate with comparison to other background subtraction algorithms. Making use of the algorithm, an indoor monitoring system is also worked out and the motion tracking process is presented in this paper.Experimental results testify the algorithms' good performances when used in an indoor monitoring system.

  5. The Importance of Resilience for Well-Being in Retirement

    Directory of Open Access Journals (Sweden)

    Cristiane Pimentel Nalin

    2015-08-01

    Full Text Available The increase in the elderly population has prompted research on retirement. This study investigated the importance of resilience, economic satisfaction, the length of retirement, and planning to well-being during retirement of 270 participants. The majority of this sample were men (64%, and the mean age was 65 years (SD = 5.7. The participants were retired members of 10 public and private organizations in Rio de Janeiro. Factor analysis and hierarchical regression were performed. The results showed that determined resilience (mastery, adaptability, confidence and perseverance and socioeconomic satisfaction were the main predictors of well-being in retirement and explained 28% of this model. The findings suggest that well-being in retirement is closely related to socioeconomic satisfaction and determined resilience. Additional research should address the importance of resilience for the well-being of retirees who are or not members of retirement associations. Resilience attitudes should be promoted in Retirement Education Programs.

  6. Adaptation and initial validation of the Patient Health Questionnaire - 9 (PHQ-9) and the Generalized Anxiety Disorder - 7 Questionnaire (GAD-7) in an Arabic speaking Lebanese psychiatric outpatient sample.

    Science.gov (United States)

    Sawaya, Helen; Atoui, Mia; Hamadeh, Aya; Zeinoun, Pia; Nahas, Ziad

    2016-05-30

    The Patient Health Questionnaire - 9 (PHQ-9) and Generalized Anxiety Disorder - 7 (GAD-7) are short screening measures used in medical and community settings to assess depression and anxiety severity. The aim of this study is to translate the screening tools into Arabic and evaluate their psychometric properties in an Arabic-speaking Lebanese psychiatric outpatient sample. The patients completed the questionnaires, among others, prior to being evaluated by a clinical psychiatrist or psychologist. The scales' internal consistency and factor structure were measured and convergent and discriminant validity were established by comparing the scores with clinical diagnoses and the Psychiatric Diagnostic Screening Questionnaire - MDD subset (PDSQ - MDD). Results showed that the PHQ-9 and GAD-7 are reliable screening tools for depression and anxiety and their factor structures replicated those reported in the literature. Sensitivity and specificity analyses showed that the PHQ-9 is sensitive but not specific at capturing depressive symptoms when compared to clinician diagnoses whereas the GAD-7 was neither sensitive nor specific at capturing anxiety symptoms. The implications of these findings are discussed in reference to the scales themselves and the cultural specificity of the Lebanese population.

  7. Adaptive compressive sensing camera

    Science.gov (United States)

    Hsu, Charles; Hsu, Ming K.; Cha, Jae; Iwamura, Tomo; Landa, Joseph; Nguyen, Charles; Szu, Harold

    2013-05-01

    We have embedded Adaptive Compressive Sensing (ACS) algorithm on Charge-Coupled-Device (CCD) camera based on the simplest concept that each pixel is a charge bucket, and the charges comes from Einstein photoelectric conversion effect. Applying the manufactory design principle, we only allow altering each working component at a minimum one step. We then simulated what would be such a camera can do for real world persistent surveillance taking into account of diurnal, all weather, and seasonal variations. The data storage has saved immensely, and the order of magnitude of saving is inversely proportional to target angular speed. We did design two new components of CCD camera. Due to the matured CMOS (Complementary metal-oxide-semiconductor) technology, the on-chip Sample and Hold (SAH) circuitry can be designed for a dual Photon Detector (PD) analog circuitry for changedetection that predicts skipping or going forward at a sufficient sampling frame rate. For an admitted frame, there is a purely random sparse matrix [Φ] which is implemented at each bucket pixel level the charge transport bias voltage toward its neighborhood buckets or not, and if not, it goes to the ground drainage. Since the snapshot image is not a video, we could not apply the usual MPEG video compression and Hoffman entropy codec as well as powerful WaveNet Wrapper on sensor level. We shall compare (i) Pre-Processing FFT and a threshold of significant Fourier mode components and inverse FFT to check PSNR; (ii) Post-Processing image recovery will be selectively done by CDT&D adaptive version of linear programming at L1 minimization and L2 similarity. For (ii) we need to determine in new frames selection by SAH circuitry (i) the degree of information (d.o.i) K(t) dictates the purely random linear sparse combination of measurement data a la [Φ]M,N M(t) = K(t) Log N(t).

  8. Human Maternal Brain Plasticity: Adaptation to Parenting

    Science.gov (United States)

    Kim, Pilyoung

    2016-01-01

    New mothers undergo dynamic neural changes that support positive adaptation to parenting and the development of mother-infant relationships. In this article, I review important psychological adaptations that mothers experience during pregnancy and the early postpartum period. I then review evidence of structural and functional plasticity in human…

  9. Adaptation of Jobs for the Disabled.

    Science.gov (United States)

    International Labour Office, Geneva (Switzerland).

    The handbook provides an illustrated guide to ways of improving useful employment of the disabled by adapting jobs. How to increase employment opportunities by making simple adjustments (adaption or redesign of tools, machines, work places) is demonstrated. The nature of occupational handicap is discussed, stressing the importance of job and…

  10. The Economics of Adaptation: Concepts, Methods and Examples

    DEFF Research Database (Denmark)

    Callaway, John MacIntosh; Naswa, Prakriti; Trærup, Sara Lærke Meltofte;

    of the costs and benefits of climate change impacts and adaptation measures are important to inform future action. Despite the growth in the volume of research and studies on the economics of climate change adaptation over the past 10 years, there are still important gaps and weaknesses in the existing...... of climate change impacts and the costs and benefits of adaptation measures at local level, where the impacts of climate change will manifest themselves, and where many adaptation actions need to be taken....

  11. Adapting agriculture with traditional knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Swiderska, Krystyna; Reid, Hannah [IIED, London (United Kingdom); Song, Yiching; Li, Jingsong [Centre for Chinese Agriculutral Policy (China); Mutta, Doris [Kenya Forestry Research Institute (Kenya)

    2011-10-15

    Over the coming decades, climate change is likely to pose a major challenge to agriculture; temperatures are rising, rainfall is becoming more variable and extreme weather is becoming a more common event. Researchers and policymakers agree that adapting agriculture to these impacts is a priority for ensuring future food security. Strategies to achieve that in practice tend to focus on modern science. But evidence, both old and new, suggests that the traditional knowledge and crop varieties of indigenous peoples and local communities could prove even more important in adapting agriculture to climate change.

  12. Improved Reliability Sensitivity Estimation and its Variance Analysis by a Novel β Hyper-plane Based Importance Sampling Method%基于β面截断重要抽样法可靠性灵敏度估计及其方差分析

    Institute of Scientific and Technical Information of China (English)

    张峰; 吕震宙; 崔利杰

    2011-01-01

    基于β面的截断重要抽样法可以用来求解单失效模式可靠性灵敏度.该方法在设计点处作失效面的虚拟切面β面,而β面将变量空间分割成重要抽样区域R和非重要抽样区域S.在R和S区域分别建立相应的截断重要抽样密度函数hR(x)和hs(x),从hR(x)和hs(x)中抽取的样本量按照R和S区域对可靠性灵敏度的贡献来分配,并通过迭代模拟计算来得到.本文推导了基于β面截断重要抽样法的可靠性灵敏度估计值方差和变异系数的计算公式,并将该方法推广应用到并联系统中.算例结果表明:在估计值相对误差小于2%、可靠性灵敏度估计值变异系数相同时,基于β面的截断重要抽样法的可靠性灵敏度估计所需的样本数比传统重要抽样法、β球截断重要抽样法计算量少.%A novel β hyper-plane based importance sampling method is presented to estimate reliability sensitivity of a structure. By introducing a virtual hyper-plane tangent to the failure surface, the variable space is separated into an importance region R and a unimportance region S, on which the truncated importance sampling functions hR(x) and hs(x) are established, respectively. The sampling numbers generated from hR(x) and hs(x) are dependent on the contribution of the reliability sensitivity, which is determined by the iterative simulations. The formulae of the reliability sensitivity estimation, the variance and the coefficient of variation are derived for the presented β hyper-plane importance sampling method. The presented method is suitable for the reliability sensitivity estimation of both the single failure mode and the multiple failure mode in parallel. Examples show that the proposed method is more efficient than the traditional importance sampling method and the β hyper-sphere importance sampling method, in the case that the variation coefficients of three estimations keep the same quantity and the relative errors of the

  13. Brazilian Portuguese transcultural adaptation of Barkley Deficits in Executive Functioning Scale (BDEFS

    Directory of Open Access Journals (Sweden)

    Victor Polignano Godoy

    2015-12-01

    Full Text Available Abstract Background Considering the importance of Executive Functions to clinical and nonclinical situations, Barkley proposed a new theory of executive functioning based on an evolutionary neuropsychological perspective and clinical research using large samples of clinical and community identified adults and children as well as children with ADHD followed to adulthood. Objective The present study aims to adapt the Barkley Deficits in Executive Functions Scales (BDEFS to Brazilian Portuguese and also assess its construct validity in a sample of normal Brazilian adults. Methods The original version of scale was adapted to Brazilian Portuguese according to the guideline from the ISPOR Task Force. To assess the semantic equivalence between the original and adapted version, both of them were applied into a sample of 25 Brazilian bilingual adults. Finally, 60 Brazilian adults completed the BDEFS and the Brazilian versions of Barratt Impulsiveness Scale (BIS-11 and Adult Self-Report Scale (ASRS-18 to assess convergent validity. Results The BDEFS Brazilian Portuguese version has semantic correspondence with the original version indicating that the adaptation procedure was successful. The BDEFS correlated significantly with the impulsivity and attention scores from the BIS-11 and ASRS-18 supporting its construct validity. Cronbach’s alpha (α = 0.961 indicated that the BDEFS translated version has satisfactory internal consistency. Discussion Together, these findings indicate the successful adaptation of the BDEFS to Brazilian Portuguese and support its utility in that population.

  14. Expressing Adaptation Strategies Using Adaptation Patterns

    Science.gov (United States)

    Zemirline, N.; Bourda, Y.; Reynaud, C.

    2012-01-01

    Today, there is a real challenge to enable personalized access to information. Several systems have been proposed to address this challenge including Adaptive Hypermedia Systems (AHSs). However, the specification of adaptation strategies remains a difficult task for creators of such systems. In this paper, we consider the problem of the definition…

  15. Approximation of NURBS Curves and Surfaces Using Adaptive Equidistant Parameterizations

    Institute of Scientific and Technical Information of China (English)

    Aziguli Wulamu; GOETTING Marc; ZECKZER Dirk

    2005-01-01

    Non-uniform rational B-spline (NURBS) curves and surfaces are very important tools for modelling curves and surfaces. Several important details, such as the choice of the sample points, of the parameterization, and of the termination condition, are however not well described. These details have a great influence on the performance of the approximation algorithm, both in terms of quality as well as time and space usage. This paper described how to sample points, examining two standard parameterizations: equidistant and chordal. A new and local parameterization, namely an adaptive equidistant model, was proposed, which enhances the equidistant model. Localization can also be used to enhance the chordal parameterization. For NURBS surfaces, one must choose which direction will be approximated first and must pay special attention to surfaces of degree 1 which have to be handled as a special case.

  16. Localizing recent adaptive evolution in the human genome

    DEFF Research Database (Denmark)

    Williamson, Scott H; Hubisz, Melissa J; Clark, Andrew G;

    2007-01-01

    Identifying genomic locations that have experienced selective sweeps is an important first step toward understanding the molecular basis of adaptive evolution. Using statistical methods that account for the confounding effects of population demography, recombination rate variation, and single......-nucleotide polymorphism ascertainment, while also providing fine-scale estimates of the position of the selected site, we analyzed a genomic dataset of 1.2 million human single-nucleotide polymorphisms genotyped in African-American, European-American, and Chinese samples. We identify 101 regions of the human genome......, clusters of olfactory receptors, genes involved in nervous system development and function, immune system genes, and heat shock genes. We also observe consistent evidence of selective sweeps in centromeric regions. In general, we find that recent adaptation is strikingly pervasive in the human genome...

  17. Cardiovascular adaptations to exercise training

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Nyberg, Michael

    2016-01-01

    Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved...... demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance...... arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle...

  18. Special session on “adaptive systems”

    NARCIS (Netherlands)

    Smit, Gerard J.M.

    2011-01-01

    Adaptive applications form an increasingly important class of applications for the embedded systems domain. Such applications differ from conventional applications in requiring automatic configuration and dynamic reconfiguration in order to meet changing environmental (run-time) requirements (thus r

  19. Adaptive immunity to fungi.

    Science.gov (United States)

    Verma, Akash; Wüthrich, Marcel; Deepe, George; Klein, Bruce

    2014-11-06

    Life-threatening fungal infections have risen sharply in recent years, owing to the advances and intensity of medical care that may blunt immunity in patients. This emerging crisis has created the growing need to clarify immune defense mechanisms against fungi with the ultimate goal of therapeutic intervention. We describe recent insights in understanding the mammalian immune defenses that are deployed against pathogenic fungi. We focus on adaptive immunity to the major medically important fungi and emphasize three elements that coordinate the response: (1) dendritic cells and subsets that are mobilized against fungi in various anatomical compartments; (2) fungal molecular patterns and their corresponding receptors that signal responses and shape the differentiation of T-cell subsets and B cells; and, ultimately (3) the effector and regulatory mechanisms that eliminate these invaders while constraining collateral damage to vital tissue. These insights create a foundation for the development of new, immune-based strategies for prevention or enhanced clearance of systemic fungal diseases.

  20. Halophilic adaptation of enzymes.

    Science.gov (United States)

    Madern, D; Ebel, C; Zaccai, G

    2000-04-01

    It is now clear that the understanding of halophilic adaptation at a molecular level requires a strategy of complementary experiments, combining molecular biology, biochemistry, and cellular approaches with physical chemistry and thermodynamics. In this review, after a discussion of the definition and composition of halophilic enzymes, the effects of salt on their activity, solubility, and stability are reviewed. We then describe how thermodynamic observations, such as parameters pertaining to solvent-protein interactions or enzyme-unfolding kinetics, depend strongly on solvent composition and reveal the important role played by water and ion binding to halophilic proteins. The three high-resolution crystal structures now available for halophilic proteins are analyzed in terms of haloadaptation, and finally cellular response to salt stress is discussed briefly.

  1. ASIC DESIGN OF ADAPTIVE THRESHOLD DENOISE DWT CHIP

    Institute of Scientific and Technical Information of China (English)

    Luo Feng; Wu Shunjun; Jiao Licheng; ZhangLinrang

    2002-01-01

    According to the relationship of wavelet transform and perfect reconstructive FIR filter banks, this paper presents a real-time chip with adaptive Donoho's non-linear soft-threshold for denoising in different levels of multi-scale space through rearranging the input data during convolving, filtering and sub-sampling. And more important, it gives a simple iterative algorithm to calculate the variance of the noise in interregna with no signal. It works well whether the signal or noise is stationary or not.

  2. Sequential sampling: a novel method in farm animal welfare assessment.

    Science.gov (United States)

    Heath, C A E; Main, D C J; Mullan, S; Haskell, M J; Browne, W J

    2016-02-01

    Lameness in dairy cows is an important welfare issue. As part of a welfare assessment, herd level lameness prevalence can be estimated from scoring a sample of animals, where higher levels of accuracy are associated with larger sample sizes. As the financial cost is related to the number of cows sampled, smaller samples are preferred. Sequential sampling schemes have been used for informing decision making in clinical trials. Sequential sampling involves taking samples in stages, where sampling can stop early depending on the estimated lameness prevalence. When welfare assessment is used for a pass/fail decision, a similar approach could be applied to reduce the overall sample size. The sampling schemes proposed here apply the principles of sequential sampling within a diagnostic testing framework. This study develops three sequential sampling schemes of increasing complexity to classify 80 fully assessed UK dairy farms, each with known lameness prevalence. Using the Welfare Quality herd-size-based sampling scheme, the first 'basic' scheme involves two sampling events. At the first sampling event half the Welfare Quality sample size is drawn, and then depending on the outcome, sampling either stops or is continued and the same number of animals is sampled again. In the second 'cautious' scheme, an adaptation is made to ensure that correctly classifying a farm as 'bad' is done with greater certainty. The third scheme is the only scheme to go beyond lameness as a binary measure and investigates the potential for increasing accuracy by incorporating the number of severely lame cows into the decision. The three schemes are evaluated with respect to accuracy and average sample size by running 100 000 simulations for each scheme, and a comparison is made with the fixed size Welfare Quality herd-size-based sampling scheme. All three schemes performed almost as well as the fixed size scheme but with much smaller average sample sizes. For the third scheme, an overall

  3. Domain adaptation for semantic role labeling of clinical text

    Science.gov (United States)

    Zhang, Yaoyun; Tang, Buzhou; Jiang, Min; Wang, Jingqi

    2015-01-01

    Objective Semantic role labeling (SRL), which extracts a shallow semantic relation representation from different surface textual forms of free text sentences, is important for understanding natural language. Few studies in SRL have been conducted in the medical domain, primarily due to lack of annotated clinical SRL corpora, which are time-consuming and costly to build. The goal of this study is to investigate domain adaptation techniques for clinical SRL leveraging resources built from newswire and biomedical literature to improve performance and save annotation costs. Materials and Methods Multisource Integrated Platform for Answering Clinical Questions (MiPACQ), a manually annotated SRL clinical corpus, was used as the target domain dataset. PropBank and NomBank from newswire and BioProp from biomedical literature were used as source domain datasets. Three state-of-the-art domain adaptation algorithms were employed: instance pruning, transfer self-training, and feature augmentation. The SRL performance using different domain adaptation algorithms was evaluated by using 10-fold cross-validation on the MiPACQ corpus. Learning curves for the different methods were generated to assess the effect of sample size. Results and Conclusion When all three source domain corpora were used, the feature augmentation algorithm achieved statistically significant higher F-measure (83.18%), compared to the baseline with MiPACQ dataset alone (F-measure, 81.53%), indicating that domain adaptation algorithms may improve SRL performance on clinical text. To achieve a comparable performance to the baseline method that used 90% of MiPACQ training samples, the feature augmentation algorithm required <50% of training samples in MiPACQ, demonstrating that annotation costs of clinical SRL can be reduced significantly by leveraging existing SRL resources from other domains. PMID:26063745

  4. Principles of adaptive optics

    CERN Document Server

    Tyson, Robert

    2010-01-01

    History and BackgroundIntroductionHistoryPhysical OpticsTerms in Adaptive OpticsSources of AberrationsAtmospheric TurbulenceThermal BloomingNonatmospheric SourcesAdaptive Optics CompensationPhase ConjugationLimitations of Phase ConjugationArtificial Guide StarsLasers for Guide StarsCombining the LimitationsLinear AnalysisPartial Phase ConjugationAdaptive Optics SystemsAdaptive Optics Imaging SystemsBeam Propagation Syst

  5. Comparison of semi-automatized assays for anti-T. gondii IgG detection in low-reactivity serum samples: importance of the results in patient counseling Comparação de ensaios semi-automatizados para pesquisa de IgG anti-T. gondii em amostras de soros de baixa reatividade: importância dos resultados no aconselhamento do paciente

    Directory of Open Access Journals (Sweden)

    Paulo Guilherme Leser

    2003-06-01

    Full Text Available Toxoplasmosis is a disease which can cause severe congenital infection and is normally diagnosed by the detection of T. gondii specific antibodies in the serum of infected patients. Several different tests allow to distinguish recent from past infections and to quantify anti-T. gondii specific IgG, and the results can be used as markers for immunity. In the present study, we compare the performance of two different methodologies, the Elfa (bioMérieux S.A and the Meia (Abbott Laboratories in detecting T. gondii specific IgG in low-reactivity sera. Of 76 analyzed samples, three presented discrepant results, being positive in the Abbott AxSYM Toxo IgG assay, and negative in the bioMérieux Vidas Toxo IgG II assay. By using other tests, the three sera were confirmed to be negative. The results are discussed in the context of their importance for patient management, especially during pregnancy.Toxoplasmose, doença conhecida por sua severidade na infecção congênita é geralmente diagnosticada pela demonstração de anticorpos específicos contra antígenos de T. gondii, presentes no soro de indivíduos infectados. Diferentes testes são disponíveis para diferenciar infecção recente de infecção pregressa, para quantificar anticorpos IgG anti-T. gondii nos soros dos pacientes e utilizar os resultados como marcadores de imunidade. Neste trabalho apresentamos os resultados do estudo comparativo de duas tecnologias, Elfa (bioMérieux S.A. e Meia (Abbott Laboratories, para pesquisa de anticorpos IgG anti-T. gondii em amostras de soros de baixa reatividade. De 76 amostras processadas, três apresentaram resultados discrepantes, reagentes para AxSYM Toxo IgG e não-reagentes para Vidas Toxo IgG II. A confirmação dos resultados, feita por bateria de testes, mostrou que todas as três amostras eram não-reagentes. Os resultados são discutidos em sua importância e orientação clínica, principalmente para a paciente gestante.

  6. Adaptation to climate change

    NARCIS (Netherlands)

    Carmin, J.; Tierney, K.; Chu, E.; Hunter, L.M.; Roberts, J.T.; Shi, L.; Dunlap, R.E.; Brulle, R.J.

    2015-01-01

    Climate change adaptation involves major global and societal challenges such as finding adequate and equitable adaptation funding and integrating adaptation and development programs. Current funding is insufficient. Debates between the Global North and South center on how best to allocate the financ

  7. Sampling in audit

    Directory of Open Access Journals (Sweden)

    Luís Antonio Garavito Herrera

    2010-04-01

    Full Text Available One of the most important things in auditing project of technology development is guarantee that the products of the project are agreeing with specifications and the expectation of the owner. In some case is unpractical to examine all the component or documentation in the project. Then if that element for examine have some characteristic or properties, is possible to take a sample and make inferences about the work with a risk under control. In this document is combine the main elements for tke a sample in statistic point of view, and a standard process of defined the size of the sample, the methodology of selection and the way of make inferences about the population from the sample.

  8. Differences in adaptations between service and manufacturing firms

    Directory of Open Access Journals (Sweden)

    Melita Rant

    2007-12-01

    Full Text Available This paper studies the differences in adaptation to the environment of service, mixed, and manufacturing companies. Adaptations are contingent on the characteristics of the environment and technology. By them, companies try to manage environmental uncertainties. The latter are subjectively perceived amplifications of small scale multi-level, lagged, nested, and nonlinear changes. Companies intend to manage perceived environmental uncertainties. They facilitate adaptations that either reduce environmental uncertainties or make an efficient reaction to unexpected external developments possible. First type of adaptations is explained by resource dependence theory transaction-cost economics: the second one is explained by contingency theory. Strategic choice theory incorporates both types of adaptations. On the grounds of those four theoretical perspectives, we constructed a research model of organizational adaptations to environmental change. The focus is on exploration of differences in adaptations among service, mixed, and manufacturing companies. Organizational adaptations are studied from internal as well as external perspective. Research is based on a survey conducted on the sample of 236 medium and large companies in the period 2000–2005 in Slovenia. Findings confirmed that companies with different technology adapt differently. Mixed companies adapt mainly through external relationships, manufacturing companies adapt mainly internally, while service companies use both types of adaptations in congruent proportions. Adaptations of mixed companies are best explained by resource dependence theory, adaptations of manufacturing companies by environmental contingency theory, and adaptations of service companies are best explained by strategic choice theory.

  9. Sample size estimation and sampling techniques for selecting a representative sample

    Directory of Open Access Journals (Sweden)

    Aamir Omair

    2014-01-01

    Full Text Available Introduction: The purpose of this article is to provide a general understanding of the concepts of sampling as applied to health-related research. Sample Size Estimation: It is important to select a representative sample in quantitative research in order to be able to generalize the results to the target population. The sample should be of the required sample size and must be selected using an appropriate probability sampling technique. There are many hidden biases which can adversely affect the outcome of the study. Important factors to consider for estimating the sample size include the size of the study population, confidence level, expected proportion of the outcome variable (for categorical variables/standard deviation of the outcome variable (for numerical variables, and the required precision (margin of accuracy from the study. The more the precision required, the greater is the required sample size. Sampling Techniques: The probability sampling techniques applied for health related research include simple random sampling, systematic random sampling, stratified random sampling, cluster sampling, and multistage sampling. These are more recommended than the nonprobability sampling techniques, because the results of the study can be generalized to the target population.

  10. Contributions to sampling statistics

    CERN Document Server

    Conti, Pier; Ranalli, Maria

    2014-01-01

    This book contains a selection of the papers presented at the ITACOSM 2013 Conference, held in Milan in June 2013. ITACOSM is the bi-annual meeting of the Survey Sampling Group S2G of the Italian Statistical Society, intended as an international  forum of scientific discussion on the developments of theory and application of survey sampling methodologies and applications in human and natural sciences. The book gathers research papers carefully selected from both invited and contributed sessions of the conference. The whole book appears to be a relevant contribution to various key aspects of sampling methodology and techniques; it deals with some hot topics in sampling theory, such as calibration, quantile-regression and multiple frame surveys, and with innovative methodologies in important topics of both sampling theory and applications. Contributions cut across current sampling methodologies such as interval estimation for complex samples, randomized responses, bootstrap, weighting, modeling, imputati...

  11. [Individual adaptation strategies].

    Science.gov (United States)

    Aldasheva, A A

    2014-01-01

    The article looks at the relation between adaptation strategy and individual style of activity based on the doctrine of human adaptation of V.I. Medvedev that enables opening up characteristics of professional activity in diverse environments. It illustrates a role and the relation between physiological and psychological mechanisms, which can vary, depending on individual adaptation strategies of a person. Theoretical and practical studies based on activity paradigm allow us to look at the basic principles of human interaction with the environment from a new perspective. Based on the law on the conceptual model of adaptation proposed by V.I. Medvedev, the article illustrates that humans are active figures in adaptation situations, modeling their own adaption strategies, using different individual styles manifested in the programs of adaptive behaviour.

  12. Adaptive research supervision : Exploring expert thesis supervisors' practical knowledge

    NARCIS (Netherlands)

    de Kleijn, Renske A M; Meijer, Paulien C.; Brekelmans, Mieke; Pilot, Albert

    2015-01-01

    Several researchers have suggested the importance of being responsive to students' needs in research supervision. Adapting support strategies to students' needs in light of the goals of a task is referred to as adaptivity. In the present study, the practice of adaptivity is explored by interviewing

  13. Noli on TV: Adaptation Criticism as Metacritism

    Directory of Open Access Journals (Sweden)

    Patrick F. Campos

    2011-06-01

    Full Text Available The paper’s project is adaptation criticism. But the paper is also, more importantly, engaged in metacriticism. It is concerned with the broader discourse of nationalism, which finds unique poignancy in Rizalian adaptation. The components of the paper are mutually enabling: the transformation of Noli Me Tangere from print to screen problematizes the motivations, processes, and implications of adaptation; while adaptation criticism, in turn, seeks to contribute to the critical tradition which engages Rizal and his impact on Philippine history and nationalism. One can presume that the screen adaptations of Rizal and his works are produced because film is a “popular” and “mass” medium. If so, Rizal adaptations always presuppose the value of the original texts, especially in relation to their nationalist context, vis-à-vis a particular conception of what the popular or mass audience is like, needs, or can appreciate. It is, therefore, of great significance and interest to address the first and only screen adaptation of the Noli for television. The paper analyzes how the intervening historical gap between the original novel and the screen adaptation, a period which has seen the rise of the “Rizal industry” and the passing of the “Rizal bill,” has been textualized in the adaptation.

  14. Cognitive adaptation to nonmelanoma skin cancer.

    Science.gov (United States)

    Czajkowska, Zofia; Radiotis, George; Roberts, Nicole; Körner, Annett

    2013-01-01

    Taylor's (1983) cognitive adaptation theory posits that when people go through life transitions, such as being diagnosed with a chronic disease, they adjust to their new reality. The adjustment process revolves around three themes: search for positive meaning in the experience or optimism, attempt to regain a sense of mastery in life, as well as an effort to enhance self-esteem. In the sample of 57 patients with nonmelanoma skin cancer the Cognitive Adaptation Index successfully predicted participants' distress (p accounting for 60% of the variance and lending support for the Taylor's theory of cognitive adaptation in this population.

  15. Nutrition and training adaptations in aquatic sports.

    Science.gov (United States)

    Mujika, Iñigo; Stellingwerff, Trent; Tipton, Kevin

    2014-08-01

    The adaptive response to training is determined by the combination of the intensity, volume, and frequency of the training. Various periodized approaches to training are used by aquatic sports athletes to achieve performance peaks. Nutritional support to optimize training adaptations should take periodization into consideration; that is, nutrition should also be periodized to optimally support training and facilitate adaptations. Moreover, other aspects of training (e.g., overload training, tapering and detraining) should be considered when making nutrition recommendations for aquatic athletes. There is evidence, albeit not in aquatic sports, that restricting carbohydrate availability may enhance some training adaptations. More research needs to be performed, particularly in aquatic sports, to determine the optimal strategy for periodizing carbohydrate intake to optimize adaptations. Protein nutrition is an important consideration for optimal training adaptations. Factors other than the total amount of daily protein intake should be considered. For instance, the type of protein, timing and pattern of protein intake and the amount of protein ingested at any one time influence the metabolic response to protein ingestion. Body mass and composition are important for aquatic sport athletes in relation to power-to-mass and for aesthetic reasons. Protein may be particularly important for athletes desiring to maintain muscle while losing body mass. Nutritional supplements, such as b-alanine and sodium bicarbonate, may have particular usefulness for aquatic athletes' training adaptation.

  16. S3-2: Colorfulness Perception Adapting to Natural Scenes

    Directory of Open Access Journals (Sweden)

    Yoko Mizokami

    2012-10-01

    Full Text Available Our visual system has the ability to adapt to the color characteristics of environment and maintain stable color appearance. Many researches on chromatic adaptation and color constancy suggested that the different levels of visual processes involve the adaptation mechanism. In the case of colorfulness perception, it has been shown that the perception changes with adaptation to chromatic contrast modulation and to surrounding chromatic variance. However, it is still not clear how the perception changes in natural scenes and what levels of visual mechanisms contribute to the perception. Here, I will mainly present our recent work on colorfulness-adaptation in natural images. In the experiment, we examined whether the colorfulness perception of an image was influenced by the adaptation to natural images with different degrees of saturation. Natural and unnatural (shuffled or phase-scrambled images are used for adapting and test images, and all combinations of adapting and test images were tested (e.g., the combination of natural adapting images and a shuffled test image. The results show that colorfulness perception was influenced by adaptation to the saturation of images. A test image appeared less colorful after adaptation to saturated images, and vice versa. The effect of colorfulness adaptation was the strongest for the combination of natural adapting and natural test images. The fact that the naturalness of the spatial structure in an image affects the strength of the adaptation effect implies that the recognition of natural scene would play an important role in the adaptation mechanism.

  17. Dubbing: adapting cultures in the global communication era

    OpenAIRE

    Lidia Canu

    2012-01-01

    Adapting translation for dubbing is not a mere linguistic fact: it is mainly the adaptation of cultures. In fact, audiovisual translation and adaptation implicitly takes into account the importance of the historical background behind the multiplicity of languages and cultures, and by doing so, it becomes a means of cultural diffusion. That peculiarity enables what we can describe as the “socio-anthropological function” of the adaptation of translation for dubbing, which is the obj...

  18. Adaptive Control and Synchronization of the Shallow Water Model

    Directory of Open Access Journals (Sweden)

    P. Sangapate

    2012-01-01

    Full Text Available The shallow water model is one of the important models in dynamical systems. This paper investigates the adaptive chaos control and synchronization of the shallow water model. First, adaptive control laws are designed to stabilize the shallow water model. Then adaptive control laws are derived to chaos synchronization of the shallow water model. The sufficient conditions for the adaptive control and synchronization have been analyzed theoretically, and the results are proved using a Barbalat's Lemma.

  19. Psychometrics behind Computerized Adaptive Testing.

    Science.gov (United States)

    Chang, Hua-Hua

    2015-03-01

    The paper provides a survey of 18 years' progress that my colleagues, students (both former and current) and I made in a prominent research area in Psychometrics-Computerized Adaptive Testing (CAT). We start with a historical review of the establishment of a large sample foundation for CAT. It is worth noting that the asymptotic results were derived under the framework of Martingale Theory, a very theoretical perspective of Probability Theory, which may seem unrelated to educational and psychological testing. In addition, we address a number of issues that emerged from large scale implementation and show that how theoretical works can be helpful to solve the problems. Finally, we propose that CAT technology can be very useful to support individualized instruction on a mass scale. We show that even paper and pencil based tests can be made adaptive to support classroom teaching.

  20. Adaptive learning in moodle: three practical cases

    Directory of Open Access Journals (Sweden)

    Dolores LERÍS LÓPEZ

    2015-12-01

    Full Text Available One of the most important challenges that the education will have to face is the need to adapt the learning process to the student’s characteristics. Nowadays it is still noticed the weak technological support and the few personalised learning practices. Two main types of e-learning platforms have been developed for last years: Learning Management Systems (LMS and Adaptive Educational Hypermedia Systems. Both lines of development are converging so that the new versions of the LMS incorporate adaptive capacities that are allowing to design individualized or differentiated instruction. In this paper the adaptive functionalities available in Moodle are checked. It is explained how to implement three adaptive instructional designs in Moodle. Moreover, it is checked their effectiveness, in terms of the learning achieved by the student, and their efficiency, by reusing materials of previous learning experiences.

  1. Group adaptation, formal darwinism and contextual analysis.

    Science.gov (United States)

    Okasha, S; Paternotte, C

    2012-06-01

    We consider the question: under what circumstances can the concept of adaptation be applied to groups, rather than individuals? Gardner and Grafen (2009, J. Evol. Biol.22: 659-671) develop a novel approach to this question, building on Grafen's 'formal Darwinism' project, which defines adaptation in terms of links between evolutionary dynamics and optimization. They conclude that only clonal groups, and to a lesser extent groups in which reproductive competition is repressed, can be considered as adaptive units. We re-examine the conditions under which the selection-optimization links hold at the group level. We focus on an important distinction between two ways of understanding the links, which have different implications regarding group adaptationism. We show how the formal Darwinism approach can be reconciled with G.C. Williams' famous analysis of group adaptation, and we consider the relationships between group adaptation, the Price equation approach to multi-level selection, and the alternative approach based on contextual analysis.

  2. An overview of importance splitting for rare event simulation

    Energy Technology Data Exchange (ETDEWEB)

    Morio, Jerome; Pastel, Rudy [Office National d' Etudes et Recherches Aerospatiales, The French Aerospace Lab, Long-term Design and System Integration Department (ONERA-DPRS-SSD), BP72, 29 avenue de la Division Leclerc, FR-92322 Chatillon Cedex (France); Le Gland, Francois, E-mail: jerome.morio@onera.f [INRIA Rennes, ASPI Applications of Interacting Particle Systems to Statistics, Campus de Beaulieu 35042, Rennes (France)

    2010-09-15

    Monte Carlo simulations are a classical tool to analyse physical systems. When unlikely events are to be simulated, the importance sampling technique is often used instead of Monte Carlo. Importance sampling has some drawbacks when the problem dimensionality is high or when the optimal importance sampling density is complex to obtain. In this paper, we focus on a quite novel but somehow confidential alternative to importance sampling called importance splitting.

  3. Quantifying adaptive evolution in the Drosophila immune system.

    Directory of Open Access Journals (Sweden)

    Darren J Obbard

    2009-10-01

    Full Text Available It is estimated that a large proportion of amino acid substitutions in Drosophila have been fixed by natural selection, and as organisms are faced with an ever-changing array of pathogens and parasites to which they must adapt, we have investigated the role of parasite-mediated selection as a likely cause. To quantify the effect, and to identify which genes and pathways are most likely to be involved in the host-parasite arms race, we have re-sequenced population samples of 136 immunity and 287 position-matched non-immunity genes in two species of Drosophila. Using these data, and a new extension of the McDonald-Kreitman approach, we estimate that natural selection fixes advantageous amino acid changes in immunity genes at nearly double the rate of other genes. We find the rate of adaptive evolution in immunity genes is also more variable than other genes, with a small subset of immune genes evolving under intense selection. These genes, which are likely to represent hotspots of host-parasite coevolution, tend to share similar functions or belong to the same pathways, such as the antiviral RNAi pathway and the IMD signalling pathway. These patterns appear to be general features of immune system evolution in both species, as rates of adaptive evolution are correlated between the D. melanogaster and D. simulans lineages. In summary, our data provide quantitative estimates of the elevated rate of adaptive evolution in immune system genes relative to the rest of the genome, and they suggest that adaptation to parasites is an important force driving molecular evolution.

  4. Quantifying adaptive evolution in the Drosophila immune system.

    Science.gov (United States)

    Obbard, Darren J; Welch, John J; Kim, Kang-Wook; Jiggins, Francis M

    2009-10-01

    It is estimated that a large proportion of amino acid substitutions in Drosophila have been fixed by natural selection, and as organisms are faced with an ever-changing array of pathogens and parasites to which they must adapt, we have investigated the role of parasite-mediated selection as a likely cause. To quantify the effect, and to identify which genes and pathways are most likely to be involved in the host-parasite arms race, we have re-sequenced population samples of 136 immunity and 287 position-matched non-immunity genes in two species of Drosophila. Using these data, and a new extension of the McDonald-Kreitman approach, we estimate that natural selection fixes advantageous amino acid changes in immunity genes at nearly double the rate of other genes. We find the rate of adaptive evolution in immunity genes is also more variable than other genes, with a small subset of immune genes evolving under intense selection. These genes, which are likely to represent hotspots of host-parasite coevolution, tend to share similar functions or belong to the same pathways, such as the antiviral RNAi pathway and the IMD signalling pathway. These patterns appear to be general features of immune system evolution in both species, as rates of adaptive evolution are correlated between the D. melanogaster and D. simulans lineages. In summary, our data provide quantitative estimates of the elevated rate of adaptive evolution in immune system genes relative to the rest of the genome, and they suggest that adaptation to parasites is an important force driving molecular evolution.

  5. Inducible competitors and adaptive diversification

    Institute of Scientific and Technical Information of China (English)

    Beren W.ROBINSON; David W.PFENNIG

    2013-01-01

    Identifying the causes of diversification is central to evolutionary biology.The ecological theory of adaptive diversification holds that the evolution of phenotypic differences between populations and species-and the formation of new species-stems from divergent natural selection,often arising from competitive interactions.Although increasing evidence suggests that phenotypic plasticity can facilitate this process,it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place.Here,we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern.First,heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of"inducible competitors".Second,once such competitively induced plasticity evolves,its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification,as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources.Thus,competition plays two important roles in adaptive diversification--one well-known and the other only now emerging-mediated through its effect on the evolution of phenotypic plasticity.

  6. Inducible competitors and adaptive diversification

    Directory of Open Access Journals (Sweden)

    Beren W. ROBINSON, David W. PFENNIG

    2013-08-01

    Full Text Available Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversification holds that the evolution of phenotypic differences between populations and species––and the formation of new species––stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of “inducible competitors”. Second, once such competitively induced plasticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification––one well-known and the other only now emerging––mediated through its effect on the evolution of phenotypic plasticity [Current Zoology 59 (4: 537–552, 2013].

  7. Statistical Inference for Data Adaptive Target Parameters.

    Science.gov (United States)

    Hubbard, Alan E; Kherad-Pajouh, Sara; van der Laan, Mark J

    2016-05-01

    Consider one observes n i.i.d. copies of a random variable with a probability distribution that is known to be an element of a particular statistical model. In order to define our statistical target we partition the sample in V equal size sub-samples, and use this partitioning to define V splits in an estimation sample (one of the V subsamples) and corresponding complementary parameter-generating sample. For each of the V parameter-generating samples, we apply an algorithm that maps the sample to a statistical target parameter. We define our sample-split data adaptive statistical target parameter as the average of these V-sample specific target parameters. We present an estimator (and corresponding central limit theorem) of this type of data adaptive target parameter. This general methodology for generating data adaptive target parameters is demonstrated with a number of practical examples that highlight new opportunities for statistical learning from data. This new framework provides a rigorous statistical methodology for both exploratory and confirmatory analysis within the same data. Given that more research is becoming "data-driven", the theory developed within this paper provides a new impetus for a greater involvement of statistical inference into problems that are being increasingly addressed by clever, yet ad hoc pattern finding methods. To suggest such potential, and to verify the predictions of the theory, extensive simulation studies, along with a data analysis based on adaptively determined intervention rules are shown and give insight into how to structure such an approach. The results show that the data adaptive target parameter approach provides a general framework and resulting methodology for data-driven science.

  8. 基于响应曲面和重要性抽样方法的热力系统参数失效概率计算%Calculation of Parameter Failure Probability of Thermodynamic System by Response Surface and Importance Sampling Method

    Institute of Scientific and Technical Information of China (English)

    尚彦龙; 蔡琦; 陈力生; 张杨伟

    2012-01-01

    本文研究了将响应曲面与重要性抽样相结合的方法用于复杂热力系统参数失效概率的计算.建立了热力系统物理过程参数失效的数学模型,在此基础上研究了将响应曲面与重要性抽样相结合的算法模型,并给出了热力系统组成设备的性能退化模型和基于重要性抽样的仿真流程,进而对反应堆净化系统工作过程中参数失效问题进行了分析计算.研究表明,对于高维、非线性特性明显并考虑性能退化的复杂热力系统参数失效概率的计算,重要性抽样法较直接抽样能以较高效率获得满意精度的计算结果,而响应曲面法存在局限;响应曲面和重要性抽样相结合的方法是分析热力系统物理过程参数失效的有效方法.%In this paper, the combined method of response surface and importance sampling was applied for calculation of parameter failure probability of the thermodynamic system. The mathematics model was present for the parameter failure of physics process in the thermodynamic system, by which the combination arithmetic model of response surface and importance sampling was established, then the performance degradation model of the components and the simulation process of parameter failure in the physics process of thermodynamic system were also present. The parameter failure probability of the purification water system in nuclear reactor was obtained by the combination method. The results show that the combination method is an effective method for the calculation of the parameter failure probability of the thermodynamic system with high dimensionality and non-linear characteristics, because of the satisfactory precision with less computing time than the direct sampling method and the draw-backs of response surface method.

  9. A General Framework for Sequential and Adaptive Methods in Survival Studies

    CERN Document Server

    Luo, Xiaolong; Ying, Zhiliang

    2011-01-01

    Adaptive treatment allocation schemes based on interim responses have generated a great deal of recent interest in clinical trials and other follow-up studies. An important application of such schemes is in survival studies, where the response variable of interest is time to the occurrence of a certain event. Due to possible dependency structures inherited from the enrollment and allocation schemes, existing approaches to survival models, including those that handle staggered entry, cannot be applied directly. This paper develops a new general framework with its theoretical foundation for handling such adaptive designs. The new approach is based on marked point processes and differs from existing approaches in that it considers entry and calender times rather than survival and calender times. Large sample properties, which are essential for statistical inference, are established. Special attention is given to the Cox model and related score processes. Applications to adaptive and sequential designs are discus...

  10. Emergy and Its Importance

    Science.gov (United States)

    Emergy is an important quantity needed for public policy analysis that is based on a complex methodology. The intent of this Environmental Research Brief is to define emergy and its importance in a manner that is accessible to everyone with at least a high school education. Emer...

  11. Assessing institutional capacities to adapt to climate change - integrating psychological dimensions in the Adaptive Capacity Wheel

    Science.gov (United States)

    Grothmann, T.; Grecksch, K.; Winges, M.; Siebenhüner, B.

    2013-03-01

    Several case studies show that "soft social factors" (e.g. institutions, perceptions, social capital) strongly affect social capacities to adapt to climate change. Many soft social factors can probably be changed faster than "hard social factors" (e.g. economic and technological development) and are therefore particularly important for building social capacities. However, there are almost no methodologies for the systematic assessment of soft social factors. Gupta et al. (2010) have developed the Adaptive Capacity Wheel (ACW) for assessing the adaptive capacity of institutions. The ACW differentiates 22 criteria to assess six dimensions: variety, learning capacity, room for autonomous change, leadership, availability of resources, fair governance. To include important psychological factors we extended the ACW by two dimensions: "adaptation motivation" refers to actors' motivation to realise, support and/or promote adaptation to climate. "Adaptation belief" refers to actors' perceptions of realisability and effectiveness of adaptation measures. We applied the extended ACW to assess adaptive capacities of four sectors - water management, flood/coastal protection, civil protection and regional planning - in North Western Germany. The assessments of adaptation motivation and belief provided a clear added value. The results also revealed some methodological problems in applying the ACW (e.g. overlap of dimensions), for which we propose methodological solutions.

  12. Assessing institutional capacities to adapt to climate change: integrating psychological dimensions in the Adaptive Capacity Wheel

    Science.gov (United States)

    Grothmann, T.; Grecksch, K.; Winges, M.; Siebenhüner, B.

    2013-12-01

    Several case studies show that social factors like institutions, perceptions and social capital strongly affect social capacities to adapt to climate change. Together with economic and technological development they are important for building social capacities. However, there are almost no methodologies for the systematic assessment of social factors. After reviewing existing methodologies we identify the Adaptive Capacity Wheel (ACW) by Gupta et al. (2010), developed for assessing the adaptive capacity of institutions, as the most comprehensive and operationalised framework to assess social factors. The ACW differentiates 22 criteria to assess 6 dimensions: variety, learning capacity, room for autonomous change, leadership, availability of resources, fair governance. To include important psychological factors we extended the ACW by two dimensions: "adaptation motivation" refers to actors' motivation to realise, support and/or promote adaptation to climate; "adaptation belief" refers to actors' perceptions of realisability and effectiveness of adaptation measures. We applied the extended ACW to assess adaptive capacities of four sectors - water management, flood/coastal protection, civil protection and regional planning - in northwestern Germany. The assessments of adaptation motivation and belief provided a clear added value. The results also revealed some methodological problems in applying the ACW (e.g. overlap of dimensions), for which we propose methodological solutions.

  13. Adaptive Pairing Reversible Watermarking.

    Science.gov (United States)

    Dragoi, Ioan-Catalin; Coltuc, Dinu

    2016-05-01

    This letter revisits the pairwise reversible watermarking scheme of Ou et al., 2013. An adaptive pixel pairing that considers only pixels with similar prediction errors is introduced. This adaptive approach provides an increased number of pixel pairs where both pixels are embedded and decreases the number of shifted pixels. The adaptive pairwise reversible watermarking outperforms the state-of-the-art low embedding bit-rate schemes proposed so far.

  14. Cortisol profiles: A test for adaptive calibration of the stress response system in maltreated and nonmaltreated youth

    Science.gov (United States)

    PECKINS, MELISSA K.; SUSMAN, ELIZABETH J.; NEGRIFF, SONYA; NOLL, JENNIE; TRICKETT, PENELOPE K.

    2017-01-01

    Throughout the life span, exposure to chronic stress such as child maltreatment is thought to contribute to future dysfunction of the stress response system (SRS) through the process of adaptive calibration. Dysfunction of the SRS is associated with numerous health and behavior problems, so it is important to understand under what conditions and what time frame adaptive calibration occurs. The present study tested for adaptive calibration of the SRS in a sample of maltreated (n = 303) and nonmaltreated (n = 151) youth during the important developmental period of adolescence. Data were used from Waves 2, 3, and 4 of a larger study of the consequences of maltreatment on health and well-being. At each time point, participants underwent the Trier Social Stress Test for Children and provided a baseline and four poststressor saliva samples to measure cortisol reactivity. Adaptive calibration was tested by performing a latent profile analysis using the five samples of salivary cortisol provided at each time point, and testing whether maltreatment status predicted the likelihood of profile membership at Time 2, Time 3, and Time 4. Three cortisol profiles emerged from the data at each time point (blunted, moderate, and elevated), and results indicated that maltreated youth were more likely than nonmaltreated youth to present with the blunted cortisol profile compared to the moderate and elevated profiles at Time 2 and Time 3, even after controlling for recent exposure to violence and trauma. At Time 4, there was no longer a difference in profile membership between maltreated and nonmaltreated youth, suggesting adaptive calibration may be a lengthy process requiring a period of years to become evident. Overall, the findings provide support for adaptive calibration and offer insight into the conditions under which adaptive calibration occurs. PMID:26535937

  15. Quantifying the adaptive cycle

    Science.gov (United States)

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  16. Adapt or Become Extinct!

    DEFF Research Database (Denmark)

    Goumas, Georgios; McKee, Sally A.; Själander, Magnus

    2011-01-01

    during the execution of an application can be utilized to adapt the execution context and may lead to performance gains beyond those provided by static information and compile-time adaptation. We consider specialization based on dynamic information like user input, architectural characteristics...... static analysis (either during ahead-of-time or just-in-time) compilation. We extend the notion of information-driven adaptation and outline the architecture of an infrastructure designed to enable information ow and adaptation throughout the life-cycle of an application....

  17. Adaptive Wireless Transceiver Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Wireless technologies are an increasingly attractive means for spatial data, input, manipulation, and distribution. Mobitrum is proposing an innovative Adaptive...

  18. Chinese Immigrant Wealth: Heterogeneity in Adaptation

    Science.gov (United States)

    Agius Vallejo, Jody; Aronson, Brian

    2016-01-01

    Chinese immigrants are a diverse and growing group whose members provide a unique opportunity to examine within-immigrant group differences in adaptation. In this paper, we move beyond thinking of national-origin groups as homogenous and study variation among Chinese immigrants in wealth ownership, a critical indicator of adaptation that attracts relatively little attention in the immigration literature. We develop an analytical approach that considers national origin, tenure in the U.S., and age to examine heterogeneity in economic adaptation among the immigrant generation. Our results show that variations among Chinese immigrants explain within-group differences in net worth, asset ownership, and debt. These differences also account for important variation between Chinese immigrants, natives, and other immigrant groups and provide important, new insight into the processes that lead to immigrant adaptation and long-term class stability. PMID:27977737

  19. The HANARO neutron reflectometer with horizontal sample geometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chong Oh; Shin, Kwan Woo [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Lee, Jeong Soo; Lee, Chang Hee; Cho, Sang Jin; Hong, Kwang Pyo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    Recently, due to increased interest of Biotechnology (BT) and Nanotechnology (NT), measurement techniques for the interface characterization of the thin film structure and depth profiling are known to be extremely important. In fact, nanosize measurement and characterization techniques are mainly targeting development of the instruments for measurement method of nano structured materials, atomic/molecular structures and magnetic/chemical/physical characterization. Reflectivity measurement, which is located in center of these divisions, is a powerful technique for the study on surfaces and interfaces of materials due to its high spatial resolution perpendicular to the surface. Most of the reflectometers now in Korea have a vertical-sample geometry, and, as a result, are suitable only for solid samples. Hence, a reflectometer with a horizontal-sample geometry is currently in great demand for various frontier researches in Korea. Thus, if a neutron liquid spectrometer is constructed in HANARO then will it be a popular instrument for liquid samples. In this paper, preliminary conceptual designs for the new reflectometer with a horizontal sample geometry at the ST3 thermal port of HANARO (REF-H), and a MCSTAS simulation for the cold source-based reflectometer (BIO-REF) are addressed. The most important concern is the reinstallation of the machine, which was originally designed for the HFBR and utilized for several years, and to adapt its functions to maximize its capabilities under the specific environment of HANARO.

  20. Adaptability in CORBA: The Mobile Proxy Approach

    DEFF Research Database (Denmark)

    Aziz, B.; Jensen, Christian D.

    2000-01-01

    are inherently open, heterogeneous, and dynamic environments integrating a wide range of platforms, operating systems and applications from a number of different sources. In this paper, we propose to use mobile proxies to provide adaptability in distributed applications integrated using the CORBA technology......Adaptability is one of the most important challenges in modern distributed systems. It may be defined as the ease with which a software application satisfies the different system constraints and the requirements of users and other applications. Adaptability is needed because distributed systems...

  1. Pulse front control with adaptive optics

    Science.gov (United States)

    Sun, B.; Salter, P. S.; Booth, M. J.

    2016-03-01

    The focusing of ultrashort laser pulses is extremely important for processes including microscopy, laser fabrication and fundamental science. Adaptive optic elements, such as liquid crystal spatial light modulators or membrane deformable mirrors, are routinely used for the correction of aberrations in these systems, leading to improved resolution and efficiency. Here, we demonstrate that adaptive elements used with ultrashort pulses should not be considered simply in terms of wavefront modification, but that changes to the incident pulse front can also occur. We experimentally show how adaptive elements may be used to engineer pulse fronts with spatial resolution.

  2. Adaptation: resources now to plan and implement

    Energy Technology Data Exchange (ETDEWEB)

    Huq, Saleemul

    2011-11-15

    Wealthy nations have committed to support developing countries to establish National Adaptation Plans (NAPs) that identify long-term priorities for responding to climate change challenges. But how and when will this support be given? Past experience suggests that national adaptation planning in expectation of future international funding is fraught with difficulties. Contributors to fast-start climate finance should release funds to developing countries straight away. These funds must be sufficient to plan longer-term adaptation strategies as well as implement immediate priorities. Equally importantly, recipients of these funds must decide for themselves how best to spend it.

  3. Adaptive Immunity to Fungi

    Science.gov (United States)

    Verma, Akash; Wüthrich, Marcel; Deepe, George; Klein, Bruce

    2015-01-01

    Life-threatening fungal infections have risen sharply in recent years, owing to the advances and intensity of medical care that may blunt immunity in patients. This emerging crisis has created the growing need to clarify immune defense mechanisms against fungi with the ultimate goal of therapeutic intervention. We describe recent insights in understanding the mammalian immune defenses that are deployed against pathogenic fungi. We focus on adaptive immunity to the major medically important fungi and emphasize three elements that coordinate the response: (1) dendritic cells and subsets that are mobilized against fungi in various anatomical compartments; (2) fungal molecular patterns and their corresponding receptors that signal responses and shape the differentiation of T-cell subsets and B cells; and, ultimately (3) the effector and regulatory mechanisms that eliminate these invaders while constraining collateral damage to vital tissue. These insights create a foundation for the development of new, immune-based strategies for prevention or enhanced clearance of systemic fungal diseases. PMID:25377140

  4. Adaptive Multimedia Retrieval: Semantics, Context, and Adaptation

    DEFF Research Database (Denmark)

    This book constitutes the thoroughly refereed post-conference proceedings of the 10th International Conference on Adaptive Multimedia Retrieval, AMR 2012, held in Copenhagen, Denmark, in October 2012. The 17 revised full papers presented were carefully reviewed and selected from numerous submissi...

  5. Parallel Adaptive Mesh Refinement

    Energy Technology Data Exchange (ETDEWEB)

    Diachin, L; Hornung, R; Plassmann, P; WIssink, A

    2005-03-04

    As large-scale, parallel computers have become more widely available and numerical models and algorithms have advanced, the range of physical phenomena that can be simulated has expanded dramatically. Many important science and engineering problems exhibit solutions with localized behavior where highly-detailed salient features or large gradients appear in certain regions which are separated by much larger regions where the solution is smooth. Examples include chemically-reacting flows with radiative heat transfer, high Reynolds number flows interacting with solid objects, and combustion problems where the flame front is essentially a two-dimensional sheet occupying a small part of a three-dimensional domain. Modeling such problems numerically requires approximating the governing partial differential equations on a discrete domain, or grid. Grid spacing is an important factor in determining the accuracy and cost of a computation. A fine grid may be needed to resolve key local features while a much coarser grid may suffice elsewhere. Employing a fine grid everywhere may be inefficient at best and, at worst, may make an adequately resolved simulation impractical. Moreover, the location and resolution of fine grid required for an accurate solution is a dynamic property of a problem's transient features and may not be known a priori. Adaptive mesh refinement (AMR) is a technique that can be used with both structured and unstructured meshes to adjust local grid spacing dynamically to capture solution features with an appropriate degree of resolution. Thus, computational resources can be focused where and when they are needed most to efficiently achieve an accurate solution without incurring the cost of a globally-fine grid. Figure 1.1 shows two example computations using AMR; on the left is a structured mesh calculation of a impulsively-sheared contact surface and on the right is the fuselage and volume discretization of an RAH-66 Comanche helicopter [35]. Note the

  6. [Postvagotomy adaptation syndrome].

    Science.gov (United States)

    Shapovalov, V A

    1998-01-01

    It was established in experiment, that the changes of the natural resistance of organism indexes and of the peritoneal cavity cytology has compensatory-adaptational character while the denervation-adaptational syndrome occurrence and progress, which may be assessed as eustress. Vagotomy and operative trauma cause qualitatively different reactions of an organism.

  7. Adaptive Wavelet Transforms

    Energy Technology Data Exchange (ETDEWEB)

    Szu, H.; Hsu, C. [Univ. of Southwestern Louisiana, Lafayette, LA (United States)

    1996-12-31

    Human sensors systems (HSS) may be approximately described as an adaptive or self-learning version of the Wavelet Transforms (WT) that are capable to learn from several input-output associative pairs of suitable transform mother wavelets. Such an Adaptive WT (AWT) is a redundant combination of mother wavelets to either represent or classify inputs.

  8. Multi-decadal range changes vs. thermal adaptation for north east Atlantic oceanic copepods in the face of climate change.

    Science.gov (United States)

    Hinder, Stephanie L; Gravenor, Mike B; Edwards, Martin; Ostle, Clare; Bodger, Owen G; Lee, Patricia L M; Walne, Antony W; Hays, Graeme C

    2014-01-01

    Populations may potentially respond to climate change in various ways including moving to new areas or alternatively staying where they are and adapting as conditions shift. Traditional laboratory and mesocosm experiments last days to weeks and thus only give a limited picture of thermal adaptation, whereas ocean warming occurring over decades allows the potential for selection of new strains better adapted to warmer conditions. Evidence for adaptation in natural systems is equivocal. We used a 50-year time series comprising of 117 056 samples in the NE Atlantic, to quantify the abundance and distribution of two particularly important and abundant members of the ocean plankton (copepods of the genus Calanus) that play a key trophic role for fisheries. Abundance of C. finmarchicus, a cold-water species, and C. helgolandicus, a warm-water species, were negatively and positively related to sea surface temperature (SST) respectively. However, the abundance vs. SST relationships for neither species changed over time in a manner consistent with thermal adaptation. Accompanying the lack of evidence for thermal adaptation there has been an unabated range contraction for C. finmarchicus and range expansion for C. helgolandicus. Our evidence suggests that thermal adaptation has not mitigated the impacts of ocean warming for dramatic range changes of these key species and points to continued dramatic climate induced changes in the biology of the oceans.

  9. Correlates of depressive symptoms among North Korean refugees adapting to South Korean society: the moderating role of perceived discrimination.

    Science.gov (United States)

    Um, Mee Young; Chi, Iris; Kim, Hee Jin; Palinkas, Lawrence A; Kim, Jae Yop

    2015-04-01

    Although the prevalence of depressive disorders among North Korean (NK) refugees living in South Korea has been reported to be twice the rate of their South Korean counterparts, little is known about the correlates of depressive symptoms among this population. Despite their escape from a politically and economically repressive setting, NK refugees continue to face multidimensional hardships during their adaptation process in South Korea, which can adversely affect their mental health. However, to our knowledge, no empirical research exists to date on depressive symptoms in the context of adaptation or perceived discrimination among NK refugees. To fill this gap, this study used a sample of 261 NK refugees in South Korea from the 2010 National Survey on Family Violence to examine associations between sociocultural adaptation, perceived discrimination, and depressive symptoms, as well as the moderation effect of discrimination on adaptation to depressive symptoms. We found that poor sociocultural adaptation and perception of discrimination were associated with increased levels of depressive symptoms. Perception of discrimination attenuated the association between better adaptation and fewer depressive symptoms, when compared to no perception of discrimination. These findings highlight the need to improve NK refugees' adaptation and integration as well as their psychological well-being in a culturally sensitive and comprehensive manner. They also underscore the importance of educating South Koreans to become accepting hosts who value diversity, yet in a homogeneous society.

  10. 76 FR 65411 - Specialty Crops; Import Regulations; Proposed Pistachio Import Requirements

    Science.gov (United States)

    2011-10-21

    ... test the second sample or rework the lot and resubmit it for testing. If the importer chooses to... notification report to the importer, Customs, and USDA. If the importer chooses to rework the lot after the... associated with certifying a disposal would be paid by the importer. Rework Procedures Although reworking...

  11. User-Centered Evaluation of Adaptive and Adaptable Systems

    NARCIS (Netherlands)

    Velsen, van Lex; Geest, van der Thea M.; Klaassen, Rob F.

    2009-01-01

    Adaptive and adaptable systems provide tailored output to various users in various contexts. While adaptive systems base their output on implicit inferences, adaptable systems use explicitly provided information. Since the presentation or output of these systems is adapted, standard user-centered ev

  12. Financing climate change adaptation.

    Science.gov (United States)

    Bouwer, Laurens M; Aerts, Jeroen C J H

    2006-03-01

    This paper examines the topic of financing adaptation in future climate change policies. A major question is whether adaptation in developing countries should be financed under the 1992 United Nations Framework Convention on Climate Change (UNFCCC), or whether funding should come from other sources. We present an overview of financial resources and propose the employment of a two-track approach: one track that attempts to secure climate change adaptation funding under the UNFCCC; and a second track that improves mainstreaming of climate risk management in development efforts. Developed countries would need to demonstrate much greater commitment to the funding of adaptation measures if the UNFCCC were to cover a substantial part of the costs. The mainstreaming of climate change adaptation could follow a risk management path, particularly in relation to disaster risk reduction. 'Climate-proofing' of development projects that currently do not consider climate and weather risks could improve their sustainability.

  13. Adaptive noise cancellation

    CERN Document Server

    Akram, N

    1999-01-01

    In this report we describe the concept of adaptive noise canceling, an alternative method of estimating signals corrupted by additive noise of interference. The method uses 'primary' input containing the corrupted signal and a 'reference' input containing noise correlated in some unknown way with the primary noise, the reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. When the reference input is free of signal and certain other conditions are met then noise in the primary input can be essentially eliminated without signal distortion. It is further shown that the adaptive filter also acts as notch filter. Simulated results illustrate the usefulness of the adaptive noise canceling technique.

  14. Adaptation of brain functional and structural networks in aging.

    Science.gov (United States)

    Lee, Annie; Ratnarajah, Nagulan; Tuan, Ta Anh; Chen, Shen-Hsing Annabel; Qiu, Anqi

    2015-01-01

    The human brain, especially the prefrontal cortex (PFC), is functionally and anatomically reorganized in order to adapt to neuronal challenges in aging. This study employed structural MRI, resting-state fMRI (rs-fMRI), and high angular resolution diffusion imaging (HARDI), and examined the functional and structural reorganization of the PFC in aging using a Chinese sample of 173 subjects aged from 21 years and above. We found age-related increases in the structural connectivity between the PFC and posterior brain regions. Such findings were partially mediated by age-related increases in the structural connectivity of the occipital lobe within the posterior brain. Based on our findings, it is thought that the PFC reorganization in aging could be partly due to the adaptation to age-related changes in the structural reorganization of the posterior brain. This thus supports the idea derived from task-based fMRI that the PFC reorganization in aging may be adapted to the need of compensation for resolving less distinctive stimulus information from the posterior brain regions. In addition, we found that the structural connectivity of the PFC with the temporal lobe was fully mediated by the temporal cortical thickness, suggesting that the brain morphology plays an important role in the functional and structural reorganization with aging.

  15. Adaptation of brain functional and structural networks in aging.

    Directory of Open Access Journals (Sweden)

    Annie Lee

    Full Text Available The human brain, especially the prefrontal cortex (PFC, is functionally and anatomically reorganized in order to adapt to neuronal challenges in aging. This study employed structural MRI, resting-state fMRI (rs-fMRI, and high angular resolution diffusion imaging (HARDI, and examined the functional and structural reorganization of the PFC in aging using a Chinese sample of 173 subjects aged from 21 years and above. We found age-related increases in the structural connectivity between the PFC and posterior brain regions. Such findings were partially mediated by age-related increases in the structural connectivity of the occipital lobe within the posterior brain. Based on our findings, it is thought that the PFC reorganization in aging could be partly due to the adaptation to age-related changes in the structural reorganization of the posterior brain. This thus supports the idea derived from task-based fMRI that the PFC reorganization in aging may be adapted to the need of compensation for resolving less distinctive stimulus information from the posterior brain regions. In addition, we found that the structural connectivity of the PFC with the temporal lobe was fully mediated by the temporal cortical thickness, suggesting that the brain morphology plays an important role in the functional and structural reorganization with aging.

  16. Import vs. Imitation?

    DEFF Research Database (Denmark)

    Kölcze, Zsófia

    2012-01-01

    in producing, maintaining and reproducing social identities, communicating new ideas and technological innovations and creating ideologies and cosmologies. Our understanding of material culture has obtained a social dimension, and we as archaeologists have become aware of the importance of making this aspect....... Instead, we have to focus on the social life and role of an artifact - whether it is an original object, imported from a different cultural sphere, or an imitation, produced locally. Through my presentation I would like to stimulate the debate about this new approach, starting off with the hoard finds...

  17. Exports to Imports

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China covers ground as it attempts to balance imports and exports after a trade deficit in the first quarter As China gears up to rebalance its economy,a key factor will be weaning its reliance on exports.The vigorous efforts are paying off as the country reported a trade deficit in the first

  18. Partner Performs More Important

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Reporter: Would you please offer an introduction to exhibition development of Frankfurt? Michael von Zitzewitz: Mess Frankfurt GmbH has made great achievements in despite of dissatisfying economy in Europe. 364 million Euro of sales volume has made Mess Frankfurt GmbH become the 2nd largest world’s exhibition corporation, overseas sales is an important fortune resource for

  19. Minimal Pairs: Minimal Importance?

    Science.gov (United States)

    Brown, Adam

    1995-01-01

    This article argues that minimal pairs do not merit as much attention as they receive in pronunciation instruction. There are other aspects of pronunciation that are of greater importance, and there are other ways of teaching vowel and consonant pronunciation. (13 references) (VWL)

  20. The Importance of Ethos.

    Science.gov (United States)

    Oft-Rose, Nancy

    1989-01-01

    Discusses how studying the 1988 Presidential Debates reveals the importance of ethos in speaking and being elected to office. Asserts that the debates also offer an excellent opportunity to teach propaganda devices or fallacies. Provides two examples from the second Presidential Debate. (MM)

  1. Interrelations between psychosocial functioning and adaptive- and maladaptive-range personality traits.

    Science.gov (United States)

    Ro, Eunyoe; Clark, Lee Anna

    2013-08-01

    Decrements in one or more domains of psychosocial functioning (e.g., poor job performance, poor interpersonal relations) are commonly observed in psychiatric patients. The purpose of this study is to increase understanding of psychosocial functioning as a broad, multifaceted construct as well as its associations with both adaptive- and maladaptive-range personality traits in both nonclinical and psychiatric outpatient samples. The study was conducted in two phases. In Study 1, a nonclinical sample (N = 429) was administered seven psychosocial functioning and adaptive-range personality trait measures. In Study 2, psychiatric outpatients (N = 181) were administered the same psychosocial functioning measures, and maladaptive- as well as adaptive-range personality trait measures. Exploratory (both studies) and confirmatory (Study 2) factor analyses indicated a common three-factor, hierarchical structure of psychosocial functioning-Well Being, Social/Interpersonal Functioning, and Basic Functioning. These psychosocial functioning domains were closely--and differentially--linked with personality traits, especially strongly so in patients. Across samples, Well Being was associated with both Neuroticism/Negative Affectivity and Extraversion/Positive Affectivity, Social/Interpersonal Functioning was associated with both Agreeableness and Conscientiousness/Disinhibition, and Basic Functioning was associated with Conscientiousness/Disinhibition, although only modestly in the nonclinical sample. These relations generally were maintained even after partialing out current general dysphoric symptoms. These findings have implications for considering psychosocial functioning as an important third domain in a tripartite model together with personality and psychopathology.

  2. An Overview of Importance Splitting for Rare Event Simulation

    Science.gov (United States)

    Morio, Jerome; Pastel, Rudy; Le Gland, Francois

    2010-01-01

    Monte Carlo simulations are a classical tool to analyse physical systems. When unlikely events are to be simulated, the importance sampling technique is often used instead of Monte Carlo. Importance sampling has some drawbacks when the problem dimensionality is high or when the optimal importance sampling density is complex to obtain. In this…

  3. Building a Middle-Range Theory of Adaptive Spirituality.

    Science.gov (United States)

    Dobratz, Marjorie C

    2016-04-01

    The purpose of this article is to describe a Roy adaptation model based- research abstraction, the findings of which were synthesized into a middle-range theory (MRT) of adaptive spirituality. The published literature yielded 21 empirical studies that investigated religion/spirituality. Quantitative results supported the influence of spirituality on quality of life, psychosocial adjustment, well-being, adaptive coping, and the self-concept mode. Qualitative findings showed the importance of spiritual expressions, values, and beliefs in adapting to chronic illness, bereavement, death, and other life transitions. These findings were abstracted into six theoretical statements, a conceptual definition of adaptive spirituality, and three hypotheses for future testing.

  4. Advanced hierarchical distance sampling

    Science.gov (United States)

    Royle, Andy

    2016-01-01

    In this chapter, we cover a number of important extensions of the basic hierarchical distance-sampling (HDS) framework from Chapter 8. First, we discuss the inclusion of “individual covariates,” such as group size, in the HDS model. This is important in many surveys where animals form natural groups that are the primary observation unit, with the size of the group expected to have some influence on detectability. We also discuss HDS integrated with time-removal and double-observer or capture-recapture sampling. These “combined protocols” can be formulated as HDS models with individual covariates, and thus they have a commonality with HDS models involving group structure (group size being just another individual covariate). We cover several varieties of open-population HDS models that accommodate population dynamics. On one end of the spectrum, we cover models that allow replicate distance sampling surveys within a year, which estimate abundance relative to availability and temporary emigration through time. We consider a robust design version of that model. We then consider models with explicit dynamics based on the Dail and Madsen (2011) model and the work of Sollmann et al. (2015). The final major theme of this chapter is relatively newly developed spatial distance sampling models that accommodate explicit models describing the spatial distribution of individuals known as Point Process models. We provide novel formulations of spatial DS and HDS models in this chapter, including implementations of those models in the unmarked package using a hack of the pcount function for N-mixture models.

  5. Adaptive network countermeasures.

    Energy Technology Data Exchange (ETDEWEB)

    McClelland-Bane, Randy; Van Randwyk, Jamie A.; Carathimas, Anthony G.; Thomas, Eric D.

    2003-10-01

    This report describes the results of a two-year LDRD funded by the Differentiating Technologies investment area. The project investigated the use of countermeasures in protecting computer networks as well as how current countermeasures could be changed in order to adapt with both evolving networks and evolving attackers. The work involved collaboration between Sandia employees and students in the Sandia - California Center for Cyber Defenders (CCD) program. We include an explanation of the need for adaptive countermeasures, a description of the architecture we designed to provide adaptive countermeasures, and evaluations of the system.

  6. [Adaptive optics for ophthalmology].

    Science.gov (United States)

    Saleh, M

    2016-04-01

    Adaptive optics is a technology enhancing the visual performance of an optical system by correcting its optical aberrations. Adaptive optics have already enabled several breakthroughs in the field of visual sciences, such as improvement of visual acuity in normal and diseased eyes beyond physiologic limits, and the correction of presbyopia. Adaptive optics technology also provides high-resolution, in vivo imaging of the retina that may eventually help to detect the onset of retinal conditions at an early stage and provide better assessment of treatment efficacy.

  7. Adaptive Vertex Fitting

    CERN Document Server

    Frühwirth, R; Vanlaer, Pascal

    2007-01-01

    Vertex fitting frequently has to deal with both mis-associated tracks and mis-measured track errors. A robust, adaptive method is presented that is able to cope with contaminated data. The method is formulated as an iterative re-weighted Kalman filter. Annealing is introduced to avoid local minima in the optimization. For the initialization of the adaptive filter a robust algorithm is presented that turns out to perform well in a wide range of applications. The tuning of the annealing schedule and of the cut-off parameter is described, using simulated data from the CMS experiment. Finally, the adaptive property of the method is illustrated in two examples.

  8. Adaptation to and Recovery from Global Catastrophe

    Directory of Open Access Journals (Sweden)

    Seth D. Baum

    2013-03-01

    Full Text Available Global catastrophes, such as nuclear war, pandemics and ecological collapse threaten the sustainability of human civilization. To date, most work on global catastrophes has focused on preventing the catastrophes, neglecting what happens to any catastrophe survivors. To address this gap in the literature, this paper discusses adaptation to and recovery from global catastrophe. The paper begins by discussing the importance of global catastrophe adaptation and recovery, noting that successful adaptation/recovery could have value on even astronomical scales. The paper then discusses how the adaptation/recovery could proceed and makes connections to several lines of research. Research on resilience theory is considered in detail and used to develop a new method for analyzing the environmental and social stressors that global catastrophe survivors would face. This method can help identify options for increasing survivor resilience and promoting successful adaptation and recovery. A key point is that survivors may exist in small isolated communities disconnected from global trade and, thus, must be able to survive and rebuild on their own. Understanding the conditions facing isolated survivors can help promote successful adaptation and recovery. That said, the processes of global catastrophe adaptation and recovery are highly complex and uncertain; further research would be of great value.

  9. A diversified portfolio model of adaptability.

    Science.gov (United States)

    Chandra, Siddharth; Leong, Frederick T L

    2016-12-01

    A new model of adaptability, the diversified portfolio model (DPM) of adaptability, is introduced. In the 1950s, Markowitz developed the financial portfolio model by demonstrating that investors could optimize the ratio of risk and return on their portfolios through risk diversification. The DPM integrates attractive features of a variety of models of adaptability, including Linville's self-complexity model, the risk and resilience model, and Bandura's social cognitive theory. The DPM draws on the concept of portfolio diversification, positing that diversified investment in multiple life experiences, life roles, and relationships promotes positive adaptation to life's challenges. The DPM provides a new integrative model of adaptability across the biopsychosocial levels of functioning. More importantly, the DPM addresses a gap in the literature by illuminating the antecedents of adaptive processes studied in a broad array of psychological models. The DPM is described in relation to the biopsychosocial model and propositions are offered regarding its utility in increasing adaptiveness. Recommendations for future research are also offered. (PsycINFO Database Record

  10. Genomic evidence for adaptation by gene duplication.

    Science.gov (United States)

    Qian, Wenfeng; Zhang, Jianzhi

    2014-08-01

    Gene duplication is widely believed to facilitate adaptation, but unambiguous evidence for this hypothesis has been found in only a small number of cases. Although gene duplication may increase the fitness of the involved organisms by doubling gene dosage or neofunctionalization, it may also result in a simple division of ancestral functions into daughter genes, which need not promote adaptation. Hence, the general validity of the adaptation by gene duplication hypothesis remains uncertain. Indeed, a genome-scale experiment found similar fitness effects of deleting pairs of duplicate genes and deleting individual singleton genes from the yeast genome, leading to the conclusion that duplication rarely results in adaptation. Here we contend that the above comparison is unfair because of a known duplication bias among genes with different fitness contributions. To rectify this problem, we compare homologous genes from the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. We discover that simultaneously deleting a duplicate gene pair in S. cerevisiae reduces fitness significantly more than deleting their singleton counterpart in S. pombe, revealing post-duplication adaptation. The duplicates-singleton difference in fitness effect is not attributable to a potential increase in gene dose after duplication, suggesting that the adaptation is owing to neofunctionalization, which we find to be explicable by acquisitions of binary protein-protein interactions rather than gene expression changes. These results provide genomic evidence for the role of gene duplication in organismal adaptation and are important for understanding the genetic mechanisms of evolutionary innovation.

  11. Import, Offshoring and Wages

    DEFF Research Database (Denmark)

    Fosse, Henrik Barslund; Maitra, Madhura

    Offshoring firms are found to pay higher average wages than purely domestic firms. We provide a unifying empirical approach by capturing the different channels through which offshoring may explain this wage difference: (i) due to change in the composition of workers (skill composition effect) (ii......) because all existing workers get higher pay (rent sharing effect). Using Danish worker-firm data we explain how much each channel contributes to higher wages. To estimate the causal effect of offshoring on wages we use China’s accession to the WTO in December 2001 - and the soon after boom in Chinese...... exports - as positive exogenous shocks to the incentive to offshore to China. Both skill composition and rent sharing effects are found to be important in explaining the resultant gain in wages. We also show that the firm’s timing in the offshoring process determines the relative importance of a channel...

  12. Importance of Mangrove Ecosystem

    OpenAIRE

    Kathiresan, K.

    2012-01-01

    Mangrove forests are extremely important coastal resources, which are vital to our socio-economic development. Much of the ecological service of mangroves lies in protecting the coast from solar UV-B radiation, “green house” effects, and fury of cyclones, floods, sea level rise, wave action and coastal erosion. Mangroves contribute significantly to the global carbon cycle and produce large amounts of litter in the form of falling leaves, branches and other debris. Besides, mangrove habitats c...

  13. Calcium is important forus.

    Institute of Scientific and Technical Information of China (English)

    高利平

    2005-01-01

    Calcium is important for our health.We must have it in our diet to stay well.A good place to get it is from dairy products like milk, cheese and ice cream.One pound of cheese has fifty times the calcium we should have every day.Other foods have less.For example,a pound of beans also has calcium.But it has only three times the amount we ought to have daily.

  14. Imported Wines Widen Appeal

    Institute of Scientific and Technical Information of China (English)

    WAN LIXIN

    2006-01-01

    @@ "There are many factors contributing to the healthy growth of the wine market in China,"says Don St. Pierre, Jr., managing partner of ASC Fine Wines (Shanghai) Co Ltd, one of China's largest importers and distributors of fine wines. "The reduction in tariffs has helped - it has made wines more affordable. But also driving growth is the rise in Chinese people's incomes and their increasing interest in enjoying what is perceived as a socially and culturally sophisticated lifestyle."

  15. Risk factor selection in rate making: EM adaptive LASSO for zero-inflated poisson regression models.

    Science.gov (United States)

    Tang, Yanlin; Xiang, Liya; Zhu, Zhongyi

    2014-06-01

    Risk factor selection is very important in the insurance industry, which helps precise rate making and studying the features of high-quality insureds. Zero-inflated data are common in insurance, such as the claim frequency data, and zero-inflation makes the selection of risk factors quite difficult. In this article, we propose a new risk factor selection approach, EM adaptive LASSO, for a zero-inflated Poisson regression model, which combines the EM algorithm and adaptive LASSO penalty. Under some regularity conditions, we show that, with probability approaching 1, important factors are selected and the redundant factors are excluded. We investigate the finite sample performance of the proposed method through a simulation study and the analysis of car insurance data from SAS Enterprise Miner database.

  16. Adaptive designs based on the truncated product method

    Directory of Open Access Journals (Sweden)

    Neuhäuser Markus

    2005-09-01

    Full Text Available Abstract Background Adaptive designs are becoming increasingly important in clinical research. One approach subdivides the study into several (two or more stages and combines the p-values of the different stages using Fisher's combination test. Methods Alternatively to Fisher's test, the recently proposed truncated product method (TPM can be applied to combine the p-values. The TPM uses the product of only those p-values that do not exceed some fixed cut-off value. Here, these two competing analyses are compared. Results When an early termination due to insufficient effects is not appropriate, such as in dose-response analyses, the probability to stop the trial early with the rejection of the null hypothesis is increased when the TPM is applied. Therefore, the expected total sample size is decreased. This decrease in the sample size is not connected with a loss in power. The TPM turns out to be less advantageous, when an early termination of the study due to insufficient effects is possible. This is due to a decrease of the probability to stop the trial early. Conclusion It is recommended to apply the TPM rather than Fisher's combination test whenever an early termination due to insufficient effects is not suitable within the adaptive design.

  17. Emotional adaptation to limb loss.

    Science.gov (United States)

    Belon, Howard P; Vigoda, Diane F

    2014-02-01

    Individuals experience multiple changes as a result of amputation. These changes not only are physical in nature but also may include psychological, financial, and comfort changes across the spectrum of an individual's life. It is important to assess the emotional responses that an individual may experience postsurgery and throughout the rehabilitation process. Grieving is a natural and normal emotional response postamputation. Grief resolution is one of the primary areas of focus in counseling amputees. This article examines various factors and strategies used in the adaptation and recovery from amputation.

  18. Introducing the Adaptive Convex Enveloping

    CERN Document Server

    Yu, Sheng

    2011-01-01

    Convexity, though extremely important in mathematical programming, has not drawn enough attention in the field of dynamic programming. This paper gives conditions for verifying convexity of the cost-to-go functions, and introduces an accurate, fast and reliable algorithm for solving convex dynamic programs with multivariate continuous states and actions, called Adaptive Convex Enveloping. This is a short introduction of the core technique created and used in my dissertation, so it is less formal, and misses some parts, such as literature review and reference, compared to a full journal paper.

  19. Partial update least-square adaptive filtering

    CERN Document Server

    Xie, Bei

    2014-01-01

    Adaptive filters play an important role in the fields related to digital signal processing and communication, such as system identification, noise cancellation, channel equalization, and beamforming. In practical applications, the computational complexity of an adaptive filter is an important consideration. The Least Mean Square (LMS) algorithm is widely used because of its low computational complexity (O(N)) and simplicity in implementation. The least squares algorithms, such as Recursive Least Squares (RLS), Conjugate Gradient (CG), and Euclidean Direction Search (EDS), can converge faster a

  20. Sparse adaptive filters for echo cancellation

    CERN Document Server

    Paleologu, Constantin

    2011-01-01

    Adaptive filters with a large number of coefficients are usually involved in both network and acoustic echo cancellation. Consequently, it is important to improve the convergence rate and tracking of the conventional algorithms used for these applications. This can be achieved by exploiting the sparseness character of the echo paths. Identification of sparse impulse responses was addressed mainly in the last decade with the development of the so-called ``proportionate''-type algorithms. The goal of this book is to present the most important sparse adaptive filters developed for echo cancellati

  1. Better economics: supporting adaptation with stakeholder analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chambwera, Muyeye; Zou, Ye; Boughlala, Mohamed

    2011-11-15

    Across the developing world, decision makers understand the need to adapt to climate change — particularly in agriculture, which supports a large proportion of low-income groups who are especially vulnerable to impacts such as increasing water scarcity or more erratic weather. But policymakers are often less clear about what adaptation action to take. Cost-benefit analyses can provide information on the financial feasibility and economic efficiency of a given policy. But such methods fail to capture the non-monetary benefits of adaptation, which can be even more important than the monetary ones. Ongoing work in Morocco shows how combining cost-benefit analysis with a more participatory stakeholder analysis can support effective decision making by identifying cross-sector benefits, highlighting areas of mutual interest among different stakeholders and more effectively assessing impacts on adaptive capacity.

  2. Investigation on children's social adaptive capacity

    Institute of Scientific and Technical Information of China (English)

    WANG Ya-ping; WANG Bao-yan; CHEN Yun-qi; WANG Ai-rong; ZHANG Rong; NIU Xiao-lin

    2002-01-01

    Objective:To understand the present conditions of Children's social adaptive capacity. Methods:social viability and its influence factors were investigated on 628 Children in 7 kindergartens of 4 cities in China. Results: The general trend of development of Child's social adaptive capacity was fairly good. The relevance ratio on the edge level was 0.3%. Of them 16.4% and 7% were excellent and extraordinary intelligence respectively. The family environment had played a very important role in child's social adaptive capacity. Conclusion: The research revealed that in the respect of training a child's social adaptive ability, the initiative of each family should be brought into full play and we should surmount the negative influence, and solve the contradiction between releasing one's control and taking care of everything, and arouse the conscious activity of the child, and ensure the unity and balance between the child's own body and the living environment.

  3. Migration from atolls as climate change adaptation

    DEFF Research Database (Denmark)

    Birk, Thomas Ladegaard Kümmel; Rasmussen, Kjeld

    2014-01-01

    Adaptive strategies are important for reducing the vulnerability of atoll communities to climate change and sea level rise in both the short and long term. This paper seeks to contribute to the emerging discourse on migration as a form of adaptation to climate change based on empirical studies...... in the two atoll communities, Reef Islands and Ontong Java, which are located in the periphery of Solomon Islands. The paper will outline current migration patterns in the two island groups and discuss how some of this migration may contribute to adaptation to climate change and other stresses. It shows...... in adaptation to climate change in exposed atoll communities, addressing some of the barriers to migration seems logical. This may be done by efforts to stimulate migrant income opportunities, by improving migrant living conditions and by improving the transport services to the islands....

  4. Adaptive Submodular Optimization under Matroid Constraints

    CERN Document Server

    Golovin, Daniel

    2011-01-01

    Many important problems in discrete optimization require maximization of a monotonic submodular function subject to matroid constraints. For these problems, a simple greedy algorithm is guaranteed to obtain near-optimal solutions. In this article, we extend this classic result to a general class of adaptive optimization problems under partial observability, where each choice can depend on observations resulting from past choices. Specifically, we prove that a natural adaptive greedy algorithm provides a $1/(p+1)$ approximation for the problem of maximizing an adaptive monotone submodular function subject to $p$ matroid constraints, and more generally over arbitrary $p$-independence systems. We illustrate the usefulness of our result on a complex adaptive match-making application.

  5. Adaptive structures - Test hardware and experimental results

    Science.gov (United States)

    Wada, Ben K.; Fanson, James L.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The facilities and procedures used at JPL to test adaptive structures such as the large deployable reflector (LDR) are described and preliminary results are reported. The applications of adaptive structures in future NASA missions are outlined, and the techniques which are employed to modify damping, stiffness, and isolation characteristics, as well as geometric changes, are listed. The development of adaptive structures is shown to be effective as a result of new actuators and sensors, and examples are listed for categories such as fiber optics, shape-memory materials, piezoelectrics, and electrorheological fluids. Some ground test results are described for laboratory truss structures and truss test beds, which are shown to be efficient and easy to assemble in space. Adaptive structures are shown to be important for precision space structures such as the LDR, and can alleviate ground test requirements.

  6. Agricultural adaptation to climate change in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents the study on agriculture adaptation toclimate change by adopting the assumed land use change strategy to resist the water shortage and to build the capacity to adapt the expected climate change in the northern China. The cost-benefit analysis result shows that assumed land use change from high water consuming rice cultivation to other crops is very effective. Over 7 billions m3 of water can be saved. Potential conflicts between different social interest groups, different regions, demand and supply, and present and future interests have been analyzed for to form a policy to implement the adaptation strategy. Trade, usually taken as one of adaptation strategies, was suggested as a policy option for to support land use change, which not only meets the consumption demand, but also, in terms of resources, imports waterresources.

  7. Dynamic optimization and adaptive controller design

    Science.gov (United States)

    Inamdar, S. R.

    2010-10-01

    In this work I present a new type of controller which is an adaptive tracking controller which employs dynamic optimization for optimizing current value of controller action for the temperature control of nonisothermal continuously stirred tank reactor (CSTR). We begin with a two-state model of nonisothermal CSTR which are mass and heat balance equations and then add cooling system dynamics to eliminate input multiplicity. The initial design value is obtained using local stability of steady states where approach temperature for cooling action is specified as a steady state and a design specification. Later we make a correction in the dynamics where material balance is manipulated to use feed concentration as a system parameter as an adaptive control measure in order to avoid actuator saturation for the main control loop. The analysis leading to design of dynamic optimization based parameter adaptive controller is presented. The important component of this mathematical framework is reference trajectory generation to form an adaptive control measure.

  8. Mouse EEG spike detection based on the adapted continuous wavelet transform

    Science.gov (United States)

    Tieng, Quang M.; Kharatishvili, Irina; Chen, Min; Reutens, David C.

    2016-04-01

    Objective. Electroencephalography (EEG) is an important tool in the diagnosis of epilepsy. Interictal spikes on EEG are used to monitor the development of epilepsy and the effects of drug therapy. EEG recordings are generally long and the data voluminous. Thus developing a sensitive and reliable automated algorithm for analyzing EEG data is necessary. Approach. A new algorithm for detecting and classifying interictal spikes in mouse EEG recordings is proposed, based on the adapted continuous wavelet transform (CWT). The construction of the adapted mother wavelet is founded on a template obtained from a sample comprising the first few minutes of an EEG data set. Main Result. The algorithm was tested with EEG data from a mouse model of epilepsy and experimental results showed that the algorithm could distinguish EEG spikes from other transient waveforms with a high degree of sensitivity and specificity. Significance. Differing from existing approaches, the proposed approach combines wavelet denoising, to isolate transient signals, with adapted CWT-based template matching, to detect true interictal spikes. Using the adapted wavelet constructed from a predefined template, the adapted CWT is calculated on small EEG segments to fit dynamical changes in the EEG recording.

  9. Exploring Adaptive Program Behavior

    DEFF Research Database (Denmark)

    Bonnichsen, Lars Frydendal; Probst, Christian W.

    Modern computer systems are increasingly complex, with ever changing bottlenecks. This makes it difficult to ensure consistent performance when porting software, or even running it. Adaptivity, ie, switching between program variations, and dynamic recompilation have been suggested as solutions. B...

  10. The genomics of adaptation.

    Science.gov (United States)

    Radwan, Jacek; Babik, Wiesław

    2012-12-22

    The amount and nature of genetic variation available to natural selection affect the rate, course and outcome of evolution. Consequently, the study of the genetic basis of adaptive evolutionary change has occupied biologists for decades, but progress has been hampered by the lack of resolution and the absence of a genome-level perspective. Technological advances in recent years should now allow us to answer many long-standing questions about the nature of adaptation. The data gathered so far are beginning to challenge some widespread views of the way in which natural selection operates at the genomic level. Papers in this Special Feature of Proceedings of the Royal Society B illustrate various aspects of the broad field of adaptation genomics. This introductory article sets up a context and, on the basis of a few selected examples, discusses how genomic data can advance our understanding of the process of adaptation.

  11. Asimovian Adaptive Agents

    CERN Document Server

    Gordon, D F

    2011-01-01

    The goal of this research is to develop agents that are adaptive and predictable and timely. At first blush, these three requirements seem contradictory. For example, adaptation risks introducing undesirable side effects, thereby making agents' behavior less predictable. Furthermore, although formal verification can assist in ensuring behavioral predictability, it is known to be time-consuming. Our solution to the challenge of satisfying all three requirements is the following. Agents have finite-state automaton plans, which are adapted online via evolutionary learning (perturbation) operators. To ensure that critical behavioral constraints are always satisfied, agents' plans are first formally verified. They are then reverified after every adaptation. If reverification concludes that constraints are violated, the plans are repaired. The main objective of this paper is to improve the efficiency of reverification after learning, so that agents have a sufficiently rapid response time. We present two solutions: ...

  12. The Adaptive Organization

    DEFF Research Database (Denmark)

    Andersen, Torben Juul; Hallin, Carina Antonia

    2016-01-01

    Contemporary organizations operate under turbulent business conditions and must adapt their strategies to ongoing changes. This article argues that sustainable organizational performance is achieved when top management directs and coordinates interactive processes anchored in emerging organizatio......Contemporary organizations operate under turbulent business conditions and must adapt their strategies to ongoing changes. This article argues that sustainable organizational performance is achieved when top management directs and coordinates interactive processes anchored in emerging...... experiential insights from the fast response processes can be aggregated systematically from frontline employees and fed into the slow process of reasoning. When the fast and slow processes interact they form a dynamic system that adapts organizational activities to the changing conditions which identifies...... the adaptive organization....

  13. Neuropsychological presentation and adaptive skills in high-functioning adolescents with visual impairment: A preliminary investigation.

    Science.gov (United States)

    Greenaway, R; Pring, L; Schepers, A; Isaacs, D P; Dale, N J

    2017-01-01

    Studies in infants and young children with congenital visual impairment (VI) have indicated early developmental vulnerabilities, conversely research with older children and adults have highlighted areas of cognitive strength. A minimal amount is known, however, about the possible combination of strengths and weaknesses in adolescence, and this present study therefore aims to explore the neuropsychological presentation and adaptive behavior profile in high-functioning adolescents with congenital VI. Participants completed a battery of commonly used neuropsychological measures assessing memory, executive function, and attention. The measures utilized focused on auditory neuropsychological function, because only subtests that could be completed with auditory administration were suitable for this sample. Parents completed standardized measures of adaptive behavior, executive function, and social communication. Compared to aged-based norms for normal sight, adolescents with VI demonstrated strengths in aspects of working memory and verbal memory. Furthermore, performance across the neuropsychological battery was within or above the average range for the majority of the sample. In contrast, parent-report measures indicated areas of weakness in adaptive functioning, social communication, and behavioral executive functioning. Overall, this study provides preliminary evidence that relative to fully sighted peers, high-functioning adolescents with VI present with an uneven profile of cognitive and adaptive skills, which has important implications for assessment and intervention.

  14. Frustratingly Easy Domain Adaptation

    CERN Document Server

    Daumé, Hal

    2009-01-01

    We describe an approach to domain adaptation that is appropriate exactly in the case when one has enough ``target'' data to do slightly better than just using only ``source'' data. Our approach is incredibly simple, easy to implement as a preprocessing step (10 lines of Perl!) and outperforms state-of-the-art approaches on a range of datasets. Moreover, it is trivially extended to a multi-domain adaptation problem, where one has data from a variety of different domains.

  15. Adaptable DC offset correction

    Science.gov (United States)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  16. Adaptation through proportion

    Science.gov (United States)

    Xiong, Liyang; Shi, Wenjia; Tang, Chao

    2016-08-01

    Adaptation is a ubiquitous feature in biological sensory and signaling networks. It has been suggested that adaptive systems may follow certain simple design principles across diverse organisms, cells and pathways. One class of networks that can achieve adaptation utilizes an incoherent feedforward control, in which two parallel signaling branches exert opposite but proportional effects on the output at steady state. In this paper, we generalize this adaptation mechanism by establishing a steady-state proportionality relationship among a subset of nodes in a network. Adaptation can be achieved by using any two nodes in the sub-network to respectively regulate the output node positively and negatively. We focus on enzyme networks and first identify basic regulation motifs consisting of two and three nodes that can be used to build small networks with proportional relationships. Larger proportional networks can then be constructed modularly similar to LEGOs. Our method provides a general framework to construct and analyze a class of proportional and/or adaptation networks with arbitrary size, flexibility and versatile functional features.

  17. Applications of adaptive focused acoustics to compound management.

    Science.gov (United States)

    Nixon, Elizabeth; Holland-Crimmin, Sue; Lupotsky, Brian; Chan, James; Curtis, Jon; Dobbs, Karen; Blaxill, Zoe

    2009-06-01

    Since the introduction of lithotripsy kidney stone therapy, Focused Acoustics and its properties have been thoroughly utilized in medicine and exploration. More recently, Compound Management is exploring its applications and benefits to sample integrity. There are 2 forms of Focused Acoustics: Acoustic Droplet Ejection and Adaptive Focused Acoustics, which work by emitting high-powered acoustic waves through water toward a focused point. This focused power results in noncontact plate-to-plate sample transfer or sample dissolution, respectively. For the purposes of this article, only Adaptive Focused Acoustics will be addressed. Adaptive Focused Acoustics uses high-powered acoustic waves to mix, homogenize, dissolve, and thaw samples. It facilitates transferable samples through noncontact, closed-container, isothermal mixing. Experimental results show significantly reduced mixing times, limited degradation, and ideal use for heat-sensitive compounds. Upon implementation, acoustic dissolution has reduced the number of samples requiring longer mixing times as well as reducing the number impacted by incomplete compound dissolution. It has also helped in increasing the overall sample concentration from 6 to 8 mM to 8 to 10 mM by ensuring complete compound solubilization. The application of Adaptive Focused Acoustics, however, cannot be applied to all Compound Management processes, such as sample thawing and low-volume sample reconstitution. This article will go on to describe the areas where Adaptive Focused Acoustics adds value as well as areas in which it has shown no clear benefit.

  18. Methodology Series Module 5: Sampling Strategies

    OpenAIRE

    Maninder Singh Setia

    2016-01-01

    Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ‘ Sampling Method’. There are essentially two types of sampling methods: 1) probability sampling – based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling – based on researcher's choice, population that accessible & available. Some of the non-probabilit...

  19. Hand calculations for transport of radioactive aerosols through sampling systems.

    Science.gov (United States)

    Hogue, Mark; Thompson, Martha; Farfan, Eduardo; Hadlock, Dennis

    2014-05-01

    Workplace air monitoring programs for sampling radioactive aerosols in nuclear facilities sometimes must rely on sampling systems to move the air to a sample filter in a safe and convenient location. These systems may consist of probes, straight tubing, bends, contractions and other components. Evaluation of these systems for potential loss of radioactive aerosols is important because significant losses can occur. However, it can be very difficult to find fully described equations to model a system manually for a single particle size and even more difficult to evaluate total system efficiency for a polydispersed particle distribution. Some software methods are available, but they may not be directly applicable to the components being evaluated and they may not be completely documented or validated per current software quality assurance requirements. This paper offers a method to model radioactive aerosol transport in sampling systems that is transparent and easily updated with the most applicable models. Calculations are shown with the R Programming Language, but the method is adaptable to other scripting languages. The method has the advantage of transparency and easy verifiability. This paper shows how a set of equations from published aerosol science models may be applied to aspiration and transport efficiency of aerosols in common air sampling system components. An example application using R calculation scripts is demonstrated. The R scripts are provided as electronic attachments.

  20. Systematic sampling with errors in sample locations

    DEFF Research Database (Denmark)

    Ziegel, Johanna; Baddeley, Adrian; Dorph-Petersen, Karl-Anton

    2010-01-01

    Systematic sampling of points in continuous space is widely used in microscopy and spatial surveys. Classical theory provides asymptotic expressions for the variance of estimators based on systematic sampling as the grid spacing decreases. However, the classical theory assumes that the sample grid...... is exactly periodic; real physical sampling procedures may introduce errors in the placement of the sample points. This paper studies the effect of errors in sample positioning on the variance of estimators in the case of one-dimensional systematic sampling. First we sketch a general approach to variance...... analysis using point process methods. We then analyze three different models for the error process, calculate exact expressions for the variances, and derive asymptotic variances. Errors in the placement of sample points can lead to substantial inflation of the variance, dampening of zitterbewegung...