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Sample records for density phd filter

  1. The multisensor PHD filter: II. Erroneous solution via Poisson magic

    Science.gov (United States)

    Mahler, Ronald

    2009-05-01

    The theoretical foundation for the probability hypothesis density (PHD) filter is the FISST multitarget differential and integral calculus. The "core" PHD filter presumes a single sensor. Theoretically rigorous formulas for the multisensor PHD filter can be derived using the FISST calculus, but are computationally intractable. A less theoretically desirable solution-the iterated-corrector approximation-must be used instead. Recently, it has been argued that an "elementary" methodology, the "Poisson-intensity approach," renders FISST obsolete. It has further been claimed that the iterated-corrector approximation is suspect, and in its place an allegedly superior "general multisensor intensity filter" has been proposed. In this and a companion paper I demonstrate that it is these claims which are erroneous. The companion paper introduces formulas for the actual "general multisensor intensity filter." In this paper I demonstrate that (1) the "general multisensor intensity filter" fails in important special cases; (2) it will perform badly in even the easiest multitarget tracking problems; and (3) these rather serious missteps suggest that the "Poisson-intensity approach" is inherently faulty.

  2. Multi-Target Detection from Full-Waveform Airborne Laser Scanner Using Phd Filter

    Science.gov (United States)

    Fuse, T.; Hiramatsu, D.; Nakanishi, W.

    2016-06-01

    We propose a new technique to detect multiple targets from full-waveform airborne laser scanner. We introduce probability hypothesis density (PHD) filter, a type of Bayesian filtering, by which we can estimate the number of targets and their positions simultaneously. PHD filter overcomes some limitations of conventional Gaussian decomposition method; PHD filter doesn't require a priori knowledge on the number of targets, assumption of parametric form of the intensity distribution. In addition, it can take a similarity between successive irradiations into account by modelling relative positions of the same targets spatially. Firstly we explain PHD filter and particle filter implementation to it. Secondly we formulate the multi-target detection problem on PHD filter by modelling components and parameters within it. At last we conducted the experiment on real data of forest and vegetation, and confirmed its ability and accuracy.

  3. Improved Bearings-Only Multi-Target Tracking with GM-PHD Filtering

    Science.gov (United States)

    Zhang, Qian; Song, Taek Lyul

    2016-01-01

    In this paper, an improved nonlinear Gaussian mixture probability hypothesis density (GM-PHD) filter is proposed to address bearings-only measurements in multi-target tracking. The proposed method, called the Gaussian mixture measurements-probability hypothesis density (GMM-PHD) filter, not only approximates the posterior intensity using a Gaussian mixture, but also models the likelihood function with a Gaussian mixture instead of a single Gaussian distribution. Besides, the target birth model of the GMM-PHD filter is assumed to be partially uniform instead of a Gaussian mixture. Simulation results show that the proposed filter outperforms the GM-PHD filter embedded with the extended Kalman filter (EKF) and the unscented Kalman filter (UKF). PMID:27626423

  4. Improved Bearings-Only Multi-Target Tracking with GM-PHD Filtering

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2016-09-01

    Full Text Available In this paper, an improved nonlinear Gaussian mixture probability hypothesis density (GM-PHD filter is proposed to address bearings-only measurements in multi-target tracking. The proposed method, called the Gaussian mixture measurements-probability hypothesis density (GMM-PHD filter, not only approximates the posterior intensity using a Gaussian mixture, but also models the likelihood function with a Gaussian mixture instead of a single Gaussian distribution. Besides, the target birth model of the GMM-PHD filter is assumed to be partially uniform instead of a Gaussian mixture. Simulation results show that the proposed filter outperforms the GM-PHD filter embedded with the extended Kalman filter (EKF and the unscented Kalman filter (UKF.

  5. GM-PHD Filter Combined with Track-Estimate Association and Numerical Interpolation

    Directory of Open Access Journals (Sweden)

    Jinguang Chen

    2015-01-01

    Full Text Available For the standard Gaussian mixture probability hypothesis density (GM-PHD filter, the number of targets can be overestimated if the clutter rate is too high or underestimated if the detection rate is too low. These problems seriously affect the accuracy of multitarget tracking for the number and the value of measurements and clutters cannot be distinguished and recognized. Therefore, we proposed an improved GM-PHD filter to tackle these problems. Firstly, a track-estimate association was implemented in the filtering process to detect and remove false-alarm targets. Secondly, a numerical interpolation technique was used to compensate the missing targets caused by low detection rate. At the end of this paper, simulation results were presented to demonstrate the proposed GM-PHD algorithm is more effective in estimating the number and state of targets than the previous ones.

  6. Particle filters for probability hypothesis density filter with the presence of unknown measurement noise covariance

    Institute of Scientific and Technical Information of China (English)

    Wu Xinhui; Huang Gaoming; Gao Jun

    2013-01-01

    In Bayesian multi-target filtering, knowledge of measurement noise variance is very important. Significant mismatches in noise parameters will result in biased estimates. In this paper, a new particle filter for a probability hypothesis density (PHD) filter handling unknown measure-ment noise variances is proposed. The approach is based on marginalizing the unknown parameters out of the posterior distribution by using variational Bayesian (VB) methods. Moreover, the sequential Monte Carlo method is used to approximate the posterior intensity considering non-lin-ear and non-Gaussian conditions. Unlike other particle filters for this challenging class of PHD fil-ters, the proposed method can adaptively learn the unknown and time-varying noise variances while filtering. Simulation results show that the proposed method improves estimation accuracy in terms of both the number of targets and their states.

  7. Adaptive Measurement Partitioning Algorithm for a Gaussian Inverse Wishart PHD Filter that Tracks Closely Spaced Extended Targets

    Directory of Open Access Journals (Sweden)

    P. Li

    2017-06-01

    Full Text Available Use of the Gaussian inverse Wishart probability hypothesis density (GIW-PHD filter has demonstrated promise as an approach to track an unknown number of extended targets. However, when targets of various sizes are spaced closely together and performing maneuvers, estimation errors will occur because measurement partitioning algorithms fail to provide the correct partitions. Specifically, the sub-partitioning algorithm fails to handle cases in which targets are of different sizes, while other partitioning approaches are sensitive to target maneuvers. This paper presents an improved partitioning algorithm for a GIW-PHD filter in order to solve the above problems. The sub-partitioning algorithm is improved by considering target extension information and by employing Mahalanobis distances to distinguish among measurement cells of different sizes. Thus, the improved approach is not sensitive to either differences in target sizes or target maneuvering. Simulation results show that the use of the proposed partitioning approach can improve the tracking performance of a GIW-PHD filter when target are spaced closely together.

  8. Kernel density estimation and marginalized-particle based probability hypothesis density filter for multi-target tracking

    Institute of Scientific and Technical Information of China (English)

    张路平; 王鲁平; 李飚; 赵明

    2015-01-01

    In order to improve the performance of the probability hypothesis density (PHD) algorithm based particle filter (PF) in terms of number estimation and states extraction of multiple targets, a new probability hypothesis density filter algorithm based on marginalized particle and kernel density estimation is proposed, which utilizes the idea of marginalized particle filter to enhance the estimating performance of the PHD. The state variables are decomposed into linear and non-linear parts. The particle filter is adopted to predict and estimate the nonlinear states of multi-target after dimensionality reduction, while the Kalman filter is applied to estimate the linear parts under linear Gaussian condition. Embedding the information of the linear states into the estimated nonlinear states helps to reduce the estimating variance and improve the accuracy of target number estimation. The meanshift kernel density estimation, being of the inherent nature of searching peak value via an adaptive gradient ascent iteration, is introduced to cluster particles and extract target states, which is independent of the target number and can converge to the local peak position of the PHD distribution while avoiding the errors due to the inaccuracy in modeling and parameters estimation. Experiments show that the proposed algorithm can obtain higher tracking accuracy when using fewer sampling particles and is of lower computational complexity compared with the PF-PHD.

  9. Vehicle Detection Based on Probability Hypothesis Density Filter

    Directory of Open Access Journals (Sweden)

    Feihu Zhang

    2016-04-01

    Full Text Available In the past decade, the developments of vehicle detection have been significantly improved. By utilizing cameras, vehicles can be detected in the Regions of Interest (ROI in complex environments. However, vision techniques often suffer from false positives and limited field of view. In this paper, a LiDAR based vehicle detection approach is proposed by using the Probability Hypothesis Density (PHD filter. The proposed approach consists of two phases: the hypothesis generation phase to detect potential objects and the hypothesis verification phase to classify objects. The performance of the proposed approach is evaluated in complex scenarios, compared with the state-of-the-art.

  10. Gaussian Sum PHD Filtering Algorithm for Nonlinear Non-Gaussian Models

    Institute of Scientific and Technical Information of China (English)

    Yin Jianjun; Zhang Jianqiu; Zhuang Zesen

    2008-01-01

    A new multi-target filtering algorithm, termed as the Gaussian sum probability hypothesis density (GSPHD) filter, is proposed for nonlinear non-Gaussian tracking models. Provided that the initial prior intensity of the states is Gaussian or can be identified as a Gaussiaa sum, the analytical results of the algorithm show that the posterior intensity at any subsequent time step remains a Gaussian sum under the assumption that the state noise, the measurement noise, target spawn intensity, new target birth intensity, target survival probability, and detection probability are all Gaussian sums. The analysis also shows that the existing Gaassian mixture probability hypothesis density (GMPHD) filter, which is unsuitable for handling the non-Gaussian noise cases, is no more than a special ease of the proposed algorithm, which fills the shortage of incapability of treating non-Gaussian noise. The multi-target tracking simulation results verify the effectiveness of the proposed GSPHD.

  11. Effects of PhD examination stress on allopregnanolone and cortisol plasma levels and peripheral benzodiazepine receptor density.

    NARCIS (Netherlands)

    Droogleever Fortuyn, H.A.; Broekhoven, F. van; Span, P.N.; Backstrom, T.; Zitman, F.G.; Verkes, R.J.

    2004-01-01

    Peripheral benzodiazepine receptor (PBR) density in blood platelets and plasma allopregnanolone concentration in humans were determined following acute stress as represented by PhD examination. Fifteen healthy PhD students participated. Heart rate, blood pressure, plasma allopregnanolone, plasma cor

  12. Probability-hypothesis-density filter for multitarget visual tracking with trajectory recognition

    Science.gov (United States)

    Wu, Jingjing; Hu, Shiqiang; Wang, Yang

    2010-12-01

    The probability-hypothesis-density (PHD) filter as a multitarget recursive Bayes filter has generated substantial interest in the visual tracking field due to its ability to handle a time-varying number of targets. But the target's trajectory cannot be identified within its own framework. To complement the ability of PHD, the auction algorithm is combined to calculate the object trajectories automatically. We present a motion detection, dynamic, and measurement equation, as well as visual multitarget tracking algorithm based on Gaussian mixture probability hypothesis density with trajectory computation in detail. Experimental results on a large video surveillance dataset show that the proposed multitarget tracking framework improves the tracker and recognizes tracks when a variable number of targets appear, merge, split, and disappear, even in cluttered scenes.

  13. A measurement-driven adaptive probability hypothesis density filter for multitarget tracking

    Institute of Scientific and Technical Information of China (English)

    Si Weijian; Wang Liwei; Qu Zhiyu

    2015-01-01

    This paper studies the dynamic estimation problem for multitarget tracking. A novel gat-ing strategy that is based on the measurement likelihood of the target state space is proposed to improve the overall effectiveness of the probability hypothesis density (PHD) filter. Firstly, a measurement-driven mechanism based on this gating technique is designed to classify the measure-ments. In this mechanism, only the measurements for the existing targets are considered in the update step of the existing targets while the measurements of newborn targets are used for exploring newborn targets. Secondly, the gating strategy enables the development of a heuristic state estima-tion algorithm when sequential Monte Carlo (SMC) implementation of the PHD filter is investi-gated, where the measurements are used to drive the particle clustering within the space gate. The resulting PHD filter can achieve a more robust and accurate estimation of the existing targets by reducing the interference from clutter. Moreover, the target birth intensity can be adaptive to detect newborn targets, which is in accordance with the birth measurements. Simulation results demonstrate the computational efficiency and tracking performance of the proposed algorithm. ? 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of CSAA&BUAA. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  14. Scalar filtered mass density functions in nonpremixed turbulent jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Drozda, Tomasz G.; Wang, Guanghua; Sankaran, Vaidyanathan; Mayo, Jackson R.; Oefelein, Joseph C.; Barlow, Robert S. [Combustion Research Facility, Sandia National Laboratories, P.O. Box 969, MS 9051, Livermore, CA 94551 (United States)

    2008-10-15

    Filtered mass density functions (FMDFs) of mixture fraction and temperature are studied by analyzing experimental data obtained from one-dimensional Raman/Rayleigh/LIF measurements of nonpremixed CH{sub 4}/H{sub 2}/N{sub 2} turbulent jet flames at Reynolds numbers of 15,200 and 22,800 (DLR-A and -B). The experimentally determined FMDFs are conditioned on the Favre filtered values of the mixture fraction and its variance. Filter widths are selected as fixed multiples of the experimentally determined dissipation length scale at each measurement location. One-dimensional filtering using a top-hat filter is performed to obtain the filtered variables used for conditioning. The FMDFs are obtained by binning the mass and filter kernel weighted samples. Emphasis is placed on the shapes of the FMDFs in the fuel-rich, fuel-lean, and stoichiometric intervals for the Favre filtered mixture fraction, and low, medium, and high values for the Favre filtered mixture fraction variance. It is found that the FMDFs of mixture fraction are unimodal in samples with low mixture fraction variance and bimodal in samples with high variance. However, the FMDFs of mixture fraction at the smallest filter size studied are unimodal for all values of the variance. The FMDFs of temperature are unimodal in samples with low mixture fraction variance, and either unimodal or bimodal, depending on the mixture fraction mean, in samples with high variance. The influence of the filter size and the jet Reynolds number on the FMDFs is also considered. (author)

  15. 免聚类粒子PHD滤波多目标状态提取方法%Multi-target state extraction for free clustering particle PHD filter

    Institute of Scientific and Technical Information of China (English)

    刘益; 王平; 高颖慧

    2015-01-01

    概率假设密度粒子滤波(P-PHD)以粒子集形式反映目标的状态信息,是一种有效的多目标跟踪方法,其关键步骤是从粒子集中准确提取多目标状态信息。提出一种免聚类概率假设密度粒子滤波多目标状态提取方法,通过分解P-PHD迭代更新过程,筛选疑似真实目标量测类别,并重新分配粒子集,根据新粒子集直接提取目标状态,可避免粒子中心聚类和粒子峰值提取过程。仿真结果表明该方法具有较高状态提取精度。%The Particle Probability Hypothesis Density filter(P-PHD) has emerged as an effective way to solve the multi-target tracking problems. Multi-target states are expressed in a series of particles with weights. It is of importance to estimate the target state from those particles in the multi-target tracking procedure. A new method to extract target states without the need of clustering is proposed. The updating step of the P-PHD is decomposed. The observation categories coming of the real-target are selected and the chosen observation categories are assigned with the same number of new particles with new weights respectively. The target state is extracted from those brand new particle clouds directly and there is no need to execute the clustering and peak extraction operation. The simulation results demonstrate that the pro-posed algorithm has a better performance than the k-means method.

  16. Experimental assessment of presumed filtered density function models

    Science.gov (United States)

    Stetsyuk, V.; Soulopoulos, N.; Hardalupas, Y.; Taylor, A. M. K. P.

    2015-06-01

    Measured filtered density functions (FDFs) as well as assumed beta distribution model of mixture fraction and "subgrid" scale (SGS) scalar variance z '' 2 ¯ , used typically in large eddy simulations, were studied by analysing experimental data, obtained from two-dimensional planar, laser induced fluorescence measurements in isothermal swirling turbulent flows at a constant Reynolds number of 29 000 for different swirl numbers (0.3, 0.58, and 1.07). Two-dimensional spatial filtering, by using a box filter, was performed in order to obtain the filtered variables, namely, resolved mean and "subgrid" scale scalar variance. These were used as inputs for assumed beta distribution of mixture fraction and top-hat FDF shape estimates. The presumed beta distribution model, top-hat FDF, and the measured filtered density functions were used to integrate a laminar flamelet solution in order to calculate the corresponding resolved temperature. The experimentally measured FDFs varied with the flow swirl number and both axial and radial positions in the flow. The FDFs were unimodal at flow regions with low SGS scalar variance, z '' 2 ¯ 0.02. Bimodal FDF could be observed for a filter size of approximately 1.5-2 times the Batchelor scale. Unimodal FDF could be observed for a filter size as large as four times the Batchelor scale under well-mixed conditions. In addition, two common computational models (a gradient assumption and a scale similarity model) for the SGS scalar variance were used with the aim to evaluate their validity through comparison with the experimental data. It was found that the gradient assumption model performed generally better than the scale similarity one.

  17. Measurements of electron density profiles using an angular filter refractometer

    Energy Technology Data Exchange (ETDEWEB)

    Haberberger, D., E-mail: dhab@lle.rochester.edu; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

    2014-05-15

    A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10{sup 21} cm{sup −3} with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ∼9 kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres.

  18. Fast ground filtering for TLS data via Scanline Density Analysis

    Science.gov (United States)

    Che, Erzhuo; Olsen, Michael J.

    2017-07-01

    Terrestrial Laser Scanning (TLS) efficiently collects 3D information based on lidar (light detection and ranging) technology. TLS has been widely used in topographic mapping, engineering surveying, forestry, industrial facilities, cultural heritage, and so on. Ground filtering is a common procedure in lidar data processing, which separates the point cloud data into ground points and non-ground points. Effective ground filtering is helpful for subsequent procedures such as segmentation, classification, and modeling. Numerous ground filtering algorithms have been developed for Airborne Laser Scanning (ALS) data. However, many of these are error prone in application to TLS data because of its different angle of view and highly variable resolution. Further, many ground filtering techniques are limited in application within challenging topography and experience difficulty coping with some objects such as short vegetation, steep slopes, and so forth. Lastly, due to the large size of point cloud data, operations such as data traversing, multiple iterations, and neighbor searching significantly affect the computation efficiency. In order to overcome these challenges, we present an efficient ground filtering method for TLS data via a Scanline Density Analysis, which is very fast because it exploits the grid structure storing TLS data. The process first separates the ground candidates, density features, and unidentified points based on an analysis of point density within each scanline. Second, a region growth using the scan pattern is performed to cluster the ground candidates and further refine the ground points (clusters). In the experiment, the effectiveness, parameter robustness, and efficiency of the proposed method is demonstrated with datasets collected from an urban scene and a natural scene, respectively.

  19. iDensity: an automatic Gabor filter-based algorithm for breast density assessment

    Science.gov (United States)

    Gamdonkar, Ziba; Tay, Kevin; Ryder, Will; Brennan, Patrick C.; Mello-Thoms, Claudia

    2015-03-01

    Abstract Although many semi-automated and automated algorithms for breast density assessment have been recently proposed, none of these have been widely accepted. In this study a novel automated algorithm, named iDensity, inspired by the human visual system is proposed for classifying mammograms into four breast density categories corresponding to the Breast Imaging Reporting and Data System (BI-RADS). For each BI-RADS category 80 cases were taken from the normal volumes of the Digital Database for Screening Mammography (DDSM). For each case only the left medio-lateral oblique was utilized. After image calibration using the provided tables of each scanner in the DDSM, the pectoral muscle and background were removed. Images were filtered by a median filter and down sampled. Images were then filtered by a filter bank consisting of Gabor filters in six orientations and 3 scales, as well as a Gaussian filter. Three gray level histogram-based features and three second order statistics features were extracted from each filtered image. Using the extracted features, mammograms were separated initially separated into two groups, low or high density, then in a second stage, the low density group was subdivided into BI-RADS I or II, and the high density group into BI-RADS III or IV. The algorithm achieved a sensitivity of 95% and specificity of 94% in the first stage, sensitivity of 89% and specificity of 95% when classifying BIRADS I and II cases, and a sensitivity of 88% and 91% specificity when classifying BI-RADS III and IV.

  20. Filtered density function approach for reactive transport in groundwater

    Science.gov (United States)

    Suciu, Nicolae; Schüler, Lennart; Attinger, Sabine; Knabner, Peter

    2016-04-01

    Spatial filtering may be used in coarse-grained simulations (CGS) of reactive transport in groundwater, similar to the large eddy simulations (LES) in turbulence. The filtered density function (FDF), stochastically equivalent to a probability density function (PDF), provides a statistical description of the sub-grid, unresolved, variability of the concentration field. Besides closing the chemical source terms in the transport equation for the mean concentration, like in LES-FDF methods, the CGS-FDF approach aims at quantifying the uncertainty over the whole hierarchy of heterogeneity scales exhibited by natural porous media. Practically, that means estimating concentration PDFs on coarse grids, at affordable computational costs. To cope with the high dimensionality of the problem in case of multi-component reactive transport and to reduce the numerical diffusion, FDF equations are solved by particle methods. But, while trajectories of computational particles are modeled as stochastic processes indexed by time, the concentration's heterogeneity is modeled as a random field, with multi-dimensional, spatio-temporal sets of indices. To overcome this conceptual inconsistency, we consider FDFs/PDFs of random species concentrations weighted by conserved scalars and we show that their evolution equations can be formulated as Fokker-Planck equations describing stochastically equivalent processes in concentration-position spaces. Numerical solutions can then be approximated by the density in the concentration-position space of an ensemble of computational particles governed by the associated Itô equations. Instead of sequential particle methods we use a global random walk (GRW) algorithm, which is stable, free of numerical diffusion, and practically insensitive to the increase of the number of particles. We illustrate the general FDF approach and the GRW numerical solution for a reduced complexity problem consisting of the transport of a single scalar in groundwater

  1. Simultaneous localization and mapping using single cluster probability hypothesis density filters

    OpenAIRE

    Lee, Chee Sing

    2015-01-01

    The majority of research in feature-based SLAM builds on the legacy of foundational work using the EKF, a single-object estimation technique. Because feature-based SLAM is an inherently multi-object problem, this has led to a number of suboptimalities in popular solutions. We develop an algorithm using the SC-PHD filter, a multi-object estimator modeled on cluster processes. This algorithm hosts capabilities not typically seen with feature-base SLAM solutions such as principled handling of cl...

  2. Homomorphic partial differential equation filtering method for electronic speckle pattern interferometry fringes based on fringe density

    Institute of Scientific and Technical Information of China (English)

    Fang Zhang; Wenyao Liu; Lin Xia; Jinjiang Wang; Yue Zhu

    2009-01-01

    Noise reduction is one of the most exciting problems in electronic speckle pattern interferometry. We present a homomorphic partial differential equation filtering method for interferometry fringe patterns. The diffusion speed of the equation is determined based on the fringe density. We test the new method on the computer-simulated fringe pattern and experimentally obtain the fringe pattern, and evaluate its filtering performance. The qualitative and quantitative analysis shows that this technique can filter off the additive and multiplicative noise of the fringe patterns effectively, and avoid blurring high-density fringe. It is more capable of improving the quality of fringe patterns than the classical filtering methods.

  3. Tree filtering for high density airborne LiDAR data

    NARCIS (Netherlands)

    Abd Rahman, M.Z.; Gorte, B.G.H.

    2008-01-01

    A high resolution Airborne LiDAR data creates better opportunity for an individual tree measurement and provides valuable results for more precise forest inventory. This paper presents tree filtering approach that able to separate dominant tree and undergrowth vegetation. The results can be used for

  4. Tree filtering for high density airborne LiDAR data

    NARCIS (Netherlands)

    Abd Rahman, M.Z.; Gorte, B.G.H.

    2008-01-01

    A high resolution Airborne LiDAR data creates better opportunity for an individual tree measurement and provides valuable results for more precise forest inventory. This paper presents tree filtering approach that able to separate dominant tree and undergrowth vegetation. The results can be used for

  5. Constrained Kalman Filtering Via Density Function Truncation for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2006-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This paper develops an analytic method of incorporating state variable inequality constraints in the Kalman filter. The resultant filter truncates the PDF (probability density function) of the Kalman filter estimate at the known constraints and then computes the constrained filter estimate as the mean of the truncated PDF. The incorporation of state variable constraints increases the computational effort of the filter but significantly improves its estimation accuracy. The improvement is demonstrated via simulation results obtained from a turbofan engine model. The turbofan engine model contains 3 state variables, 11 measurements, and 10 component health parameters. It is also shown that the truncated Kalman filter may be a more accurate way of incorporating inequality constraints than other constrained filters (e.g., the projection approach to constrained filtering).

  6. A Quantitative Analysis on Two RFS-Based Filtering Methods for Multicell Tracking

    Directory of Open Access Journals (Sweden)

    Yayun Ren

    2014-01-01

    Full Text Available Multiobject filters developed from the theory of random finite sets (RFS have recently become well-known methods for solving multiobject tracking problem. In this paper, we present two RFS-based filtering methods, Gaussian mixture probability hypothesis density (GM-PHD filter and multi-Bernoulli filter, to quantitatively analyze their performance on tracking multiple cells in a series of low-contrast image sequences. The GM-PHD filter, under linear Gaussian assumptions on the cell dynamics and birth process, applies the PHD recursion to propagate the posterior intensity in an analytic form, while the multi-Bernoulli filter estimates the multitarget posterior density through propagating the parameters of a multi-Bernoulli RFS that approximates the posterior density of multitarget RFS. Numerous performance comparisons between the two RFS-based methods are carried out on two real cell images sequences and demonstrate that both yield satisfactory results that are in good agreement with manual tracking method.

  7. Time-varying Combinations of Predictive Densities using Nonlinear Filtering

    NARCIS (Netherlands)

    M. Billio (Monica); R. Casarin (Roberto); F. Ravazzolo (Francesco); H.K. van Dijk (Herman)

    2012-01-01

    textabstractWe propose a Bayesian combination approach for multivariate predictive densities which relies upon a distributional state space representation of the combination weights. Several specifications of multivariate time-varying weights are introduced with a particular focus on weight dynamics

  8. Particle filter with importance density function generated by updated system equation

    Institute of Scientific and Technical Information of China (English)

    左军毅; 贾颖娜; 张炜; 高全学

    2013-01-01

    The current measurement was exploited in a more efficient way. Firstly, the system equation was updated by introducing a correction term, which depends on the current measurement and can be obtained by running a suboptimal filter. Then, a new importance density function(IDF) was defined by the updated system equation. Particles drawn from the new IDF are more likely to be in the significant region of state space and the estimation accuracy can be improved. By using different suboptimal filter, different particle filters(PFs) can be developed in this framework. Extensions of this idea were also proposed by iteratively updating the system equation using particle filter itself, resulting in the iterated particle filter. Simulation results demonstrate the effectiveness of the proposed IDF.

  9. Decoding continuous limb movements from high-density epidural electrode arrays using custom spatial filters

    Science.gov (United States)

    Marathe, A. R.; Taylor, D. M.

    2013-06-01

    Objective. Our goal was to identify spatial filtering methods that would improve decoding of continuous arm movements from epidural field potentials as well as demonstrate the use of the epidural signals in a closed-loop brain-machine interface (BMI) system in monkeys. Approach. Eleven spatial filtering options were compared offline using field potentials collected from 64-channel high-density epidural arrays in monkeys. Arrays were placed over arm/hand motor cortex in which intracortical microelectrodes had previously been implanted and removed leaving focal cortical damage but no lasting motor deficits. Spatial filters tested included: no filtering, common average referencing (CAR), principle component analysis, and eight novel modifications of the common spatial pattern (CSP) algorithm. The spatial filtering method and decoder combination that performed the best offline was then used online where monkeys controlled cursor velocity using continuous wrist position decoded from epidural field potentials in real time. Main results. Optimized CSP methods improved continuous wrist position decoding accuracy by 69% over CAR and by 80% compared to no filtering. Kalman decoders performed better than linear regression decoders and benefitted from including more spatially-filtered signals but not from pre-smoothing the calculated power spectra. Conversely, linear regression decoders required fewer spatially-filtered signals and were improved by pre-smoothing the power values. The ‘position-to-velocity’ transformation used during online control enabled the animals to generate smooth closed-loop movement trajectories using the somewhat limited position information available in the epidural signals. The monkeys’ online performance significantly improved across days of closed-loop training. Significance. Most published BMI studies that use electrocorticographic signals to decode continuous limb movements either use no spatial filtering or CAR. This study suggests a

  10. 基于N记忆簇标记SMC-PHD滤波的量子跟踪%Quantum dots tracking with N-memory cluster-indexed SMC-PHD filter

    Institute of Scientific and Technical Information of China (English)

    陈柏生; 陈锻生; 王靖

    2012-01-01

    使用PHD粒子滤波跟踪量子以满足特定生物信息学应用的需求,并结合簇标记技术实现多目标航迹关联.针对簇标记技术存在的“标签漂移”问题,提出一种N记忆簇标记方法用于控制算法对不稳定目标的敏感度.它通过记忆和对比过去N个时刻的目标状态可以有效降低目标频繁出没对目标估计和跟踪带来的干扰.实验结果表明该方法可以对具有高随机动态的量子目标实现较准确、鲁棒的航迹跟踪.%A Cluster-Indexed SMC-PHD filter was presented to track quantum dots for certain biological purpose. It committed track association by labeling targets with track numbers. One problem of it is the labels of targets shift often when dealing with unsteady targets. The label shifting made it hard to obtain long-term tracks. A novel N-memory cluster-indexed SMC-PHD filter was proposed to control the sensitivity to targets birth and death. It checked the tracks back N time intervals to find out if any one of them could be associated with the currently emerging targets, and thereby, rejected false detection alarm resulting from the go-and-back of unsteady targets. Results show the method successfully track quantum dots of high dynamics.

  11. Recovering the nonlinear density field from the galaxy distribution with a Poisson-Lognormal filter

    CERN Document Server

    Kitaura, Francisco S; Metcalf, R Benton

    2009-01-01

    We present a general expression for a lognormal filter given an arbitrary nonlinear galaxy bias. We derive this filter as the maximum a posteriori solution assuming a lognormal prior distribution for the matter field with a given mean field and modeling the observed galaxy distribution by a Poissonian process. We have performed a three-dimensional implementation of this filter with a very efficient Newton-Krylov inversion scheme. Furthermore, we have tested it with a dark matter N-body simulation assuming a unit galaxy bias relation and compared the results with previous density field estimators like the inverse weighting scheme and Wiener filtering. Our results show good agreement with the underlying dark matter field for overdensities even above delta~1000 which exceeds by one order of magnitude the regime in which the lognormal is expected to be valid. The reason is that for our filter the lognormal assumption enters as a prior distribution function, but the maximum a posteriori solution is also conditione...

  12. Lagrangian filtered density function for LES-based stochastic modelling of turbulent dispersed flows

    CERN Document Server

    Innocenti, A; Chibbaro, S

    2016-01-01

    The Eulerian-Lagrangian approach based on Large-Eddy Simulation (LES) is one of the most promising and viable numerical tools to study turbulent dispersed flows when the computational cost of Direct Numerical Simulation (DNS) becomes too expensive. The applicability of this approach is however limited if the effects of the Sub-Grid Scales (SGS) of the flow on particle dynamics are neglected. In this paper, we propose to take these effects into account by means of a Lagrangian stochastic SGS model for the equations of particle motion. The model extends to particle-laden flows the velocity-filtered density function method originally developed for reactive flows. The underlying filtered density function is simulated through a Lagrangian Monte Carlo procedure that solves for a set of Stochastic Differential Equations (SDEs) along individual particle trajectories. The resulting model is tested for the reference case of turbulent channel flow, using a hybrid algorithm in which the fluid velocity field is provided b...

  13. Dynamic Adaptive Median Filter (DAMF for Removal of High Density Impulse Noise

    Directory of Open Access Journals (Sweden)

    Punyaban Patel

    2012-10-01

    Full Text Available This paper proposes a novel adaptive filtering scheme to remove impulse noise from images. The scheme replaces the corrupted test pixel with the median value of non-corrupted neighboring pixels selected from a window dynamically. If the number of non-corrupted pixels in the selected window is not sufficient, a window of next higher size is chosen. Thus window size is automatically adapted based on the density of noise in the image as well as the density of corruption local to a window. As a result window size may vary pixel to pixel while filtering. The scheme is simple to implement and do not require multiple iterations. The efficacy of the proposed scheme is evaluated with respect to subjective as well as objective parameters on standard images on various noise densities. Comparative analysis reveals that the proposed scheme has improved performance over other schemes, preferably in high density impulse noise cases. Further, the computational overhead is also less as compared its competent scheme.

  14. Density-based Monte Carlo filter and its applications in nonlinear stochastic differential equation models.

    Science.gov (United States)

    Huang, Guanghui; Wan, Jianping; Chen, Hui

    2013-02-01

    Nonlinear stochastic differential equation models with unobservable state variables are now widely used in analysis of PK/PD data. Unobservable state variables are usually estimated with extended Kalman filter (EKF), and the unknown pharmacokinetic parameters are usually estimated by maximum likelihood estimator. However, EKF is inadequate for nonlinear PK/PD models, and MLE is known to be biased downwards. A density-based Monte Carlo filter (DMF) is proposed to estimate the unobservable state variables, and a simulation-based M estimator is proposed to estimate the unknown parameters in this paper, where a genetic algorithm is designed to search the optimal values of pharmacokinetic parameters. The performances of EKF and DMF are compared through simulations for discrete time and continuous time systems respectively, and it is found that the results based on DMF are more accurate than those given by EKF with respect to mean absolute error.

  15. Lack of correlation of glucose levels in filtered blood plasma to density and conductivity measurements.

    Science.gov (United States)

    Gordon, David M; Ash, Stephen R

    2009-01-01

    The purpose of this research project was to determine whether the glucose level of a blood plasma sample from a diabetic patient could be predicted by measuring the density and conductivity of ultrafiltrate of plasma created by a 30,000 m.w. cutoff membrane. Conductivity of the plasma filtrate measures electrolyte concentration and should correct density measurements for changes in electrolytes and water concentration. In vitro studies were performed measuring conductivity and density of solutions of varying glucose and sodium chloride concentrations. Plasma from seven hospitalized patients with diabetes was filtered across a 30,000 m.w. cutoff membrane. The filtrate density and conductivity were measured and correlated to glucose levels. In vitro studies confirmed the ability to predict glucose from density and conductivity measurements, in varying concentrations of glucose and saline. In plasma filtrate, the conductivity and density measurements of ultrafiltrate allowed estimation of glucose in some patients with diabetes but not others. The correlation coefficient for the combined patient data was 0.45 which was significant but only explained 20% of the variability in the glucose levels. Individually, the correlation was significant in only two of the seven patients with correlation coefficients of 0.79 and 0.88. The reasons for lack of correlation are not clear, and cannot be explained by generation of idiogenic osmoles, effects of alcohol dehydrogenase, water intake, etc. This combination of physical methods for glucose measurement is not a feasible approach to measuring glucose in plasma filtrate.

  16. Improving the filterability and solid density of ranitidine hydrochloride Form 1.

    Science.gov (United States)

    Mirmehrabi, Mahmoud; Rohani, Sohrab; Murthy, K S Keshava; Radatus, Bruno

    2004-07-01

    Ranitidine hydrochloride Form 1 produced by the original method (Price et al., 1978 US patent) has poor filtration and drying characteristics, which make it less desirable commercially in comparison with Form 2. This article shows that the operating parameters have significant influence on the final properties of Form 1. In terms of filterability and solid bulk density, it was found that at a higher temperature (approximately 48 degrees C), the viscosity of the slurry decreased and improved product quality as compared with operating at room temperature (approximately 25 degrees C). It was found that the rapid addition of acid to the ranitidine base increased product density but led to higher residual solvent inclusion. The presence of excess ranitidine base in the solution and also the manner of reactant addition had a significant influence on the onset of nucleation and the rate of crystallization. The best results in terms of filterability and bulk solid density were obtained using an initial pH of 5.3 and then increasing it to 6.3-6.4 after the onset of nucleation.

  17. Representation of Probability Density Functions from Orbit Determination using the Particle Filter

    Science.gov (United States)

    Mashiku, Alinda K.; Garrison, James; Carpenter, J. Russell

    2012-01-01

    Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty. In order to obtain an accurate representation of the probability density function (PDF) that incorporates higher order statistical information, we propose the use of nonlinear estimation methods such as the Particle Filter. The Particle Filter (PF) is capable of providing a PDF representation of the state estimates whose accuracy is dependent on the number of particles or samples used. For this method to be applicable to real case scenarios, we need a way of accurately representing the PDF in a compressed manner with little information loss. Hence we propose using the Independent Component Analysis (ICA) as a non-Gaussian dimensional reduction method that is capable of maintaining higher order statistical information obtained using the PF. Methods such as the Principal Component Analysis (PCA) are based on utilizing up to second order statistics, hence will not suffice in maintaining maximum information content. Both the PCA and the ICA are applied to two scenarios that involve a highly eccentric orbit with a lower apriori uncertainty covariance and a less eccentric orbit with a higher a priori uncertainty covariance, to illustrate the capability of the ICA in relation to the PCA.

  18. Phase-visibility modulating interferometry by binary non-quadrature amplitude modulation with neutral density filters

    Science.gov (United States)

    Rivera-Ortega, Uriel; Meneses-Fabian, Cruz; Rodriguez-Zurita, Gustavo; Robledo-Sanchez, Carlos

    2014-04-01

    An alternative method for phase retrieval based on spatial and binary non-quadrature amplitude modulation (NQAM) is presented. This proposal is based on the superposition of a probe beam with a reference beam modulated in phase and amplitude (PAM) by NQAM, which is implemented by two neutral density filters (NDF) in a three-beam Mach-Zehnder interferometer (MZI). The principal advantage of this proposal lies in an analytical relationship between the variations of phase and visibility in an interferogram with the variations in the amplitudes of the reference beams used to implement NQAM; thus, the interferograms can be normalized and their introduced phase variations can be known from the measured intensities. Consequently it is possible to successfully retrieve the object phase. It is worthy to note that this method is capable of accepting that the phase and visibility variations in the interferograms could be spatial functions.

  19. Lagrangian filtered density function for LES-based stochastic modelling of turbulent particle-laden flows

    Science.gov (United States)

    Innocenti, Alessio; Marchioli, Cristian; Chibbaro, Sergio

    2016-11-01

    The Eulerian-Lagrangian approach based on Large-Eddy Simulation (LES) is one of the most promising and viable numerical tools to study particle-laden turbulent flows, when the computational cost of Direct Numerical Simulation (DNS) becomes too expensive. The applicability of this approach is however limited if the effects of the Sub-Grid Scales (SGSs) of the flow on particle dynamics are neglected. In this paper, we propose to take these effects into account by means of a Lagrangian stochastic SGS model for the equations of particle motion. The model extends to particle-laden flows the velocity-filtered density function method originally developed for reactive flows. The underlying filtered density function is simulated through a Lagrangian Monte Carlo procedure that solves a set of Stochastic Differential Equations (SDEs) along individual particle trajectories. The resulting model is tested for the reference case of turbulent channel flow, using a hybrid algorithm in which the fluid velocity field is provided by LES and then used to advance the SDEs in time. The model consistency is assessed in the limit of particles with zero inertia, when "duplicate fields" are available from both the Eulerian LES and the Lagrangian tracking. Tests with inertial particles were performed to examine the capability of the model to capture the particle preferential concentration and near-wall segregation. Upon comparison with DNS-based statistics, our results show improved accuracy and considerably reduced errors with respect to the case in which no SGS model is used in the equations of particle motion.

  20. Improving Recording Density of All-Optical Magnetic Storage by Using High-Pass Angular Spectrum Filters

    Institute of Scientific and Technical Information of China (English)

    ZHUANG You-Yi; ZHANG Yao-Ju

    2009-01-01

    A new design is presented to improve the magnetic recording density in all-optical magnetic storage.By using the high numerical lens with a high-pass angular spectrum filter, circularly polarized laser pulses are focused into the magneto-optic film with the perpendicular anisotropy.Magnetization of the film is induced by the inverse Faraday effect.As the obstructed angle of the filter increases the magnetic recording density increases evidently.The magnetization intensity and the sidelobe effect are also discussed.

  1. Towards a filtered density function approach for reactive transport in groundwater

    Science.gov (United States)

    Suciu, N.; Schüler, L.; Attinger, S.; Knabner, P.

    2016-04-01

    Evolution equations for probability density functions (PDFs) and filtered density functions (FDFs) of random species concentrations weighted by conserved scalars are formulated as Fokker-Planck equations describing stochastically equivalent processes in concentration-position spaces. This approach provides consistent numerical PDF/FDF solutions, given by the density in the concentration-position space of an ensemble of computational particles governed by the associated Itô equations. The solutions are obtained by a global random walk (GRW) algorithm, which is stable, free of numerical diffusion, and practically insensitive to the increase of the number of particles. The general FDF approach and the GRW numerical solution are illustrated for a reduced complexity problem consisting of the transport of a single scalar in groundwater. Randomness is induced by the stochastic parameterization of the hydraulic conductivity, characterized by short range correlations and small variance. The objective is to infer the statistics of the random concentration sampled at the plume center of mass, integrated over the transverse dimension of a two-dimensional spatial domain. The PDF/FDF problem can therefore be formulated in a two-dimensional domain as well, a spatial dimension and one in the concentration space. The upscaled drift and diffusion coefficients describing the PDF transport in the physical space are estimated on single-trajectories of diffusion in velocity fields with short-range correlations, owing to their self-averaging property. The mixing coefficients describing the PDF transport in concentration spaces are parameterized by the trend and the noise inferred from the statistical analysis of an ensemble of simulated concentration time series, as well as by classical mixing models. A Gaussian spatial filter applied to a Kraichnan velocity field generator is used to construct coarse-grained simulations (CGS) for FDF problems. The purposes of the CGS simulations are

  2. A novel consistent photomicrography technique using a reference slide made of neutral density filter.

    Science.gov (United States)

    Kim, Jong Yeob; Kim, Ji Woong; Seo, Soo Hong; Kye, Young Chul; Ahn, Hyo Hyun

    2011-05-01

    Obtaining consistent photomicrographic images of pathology slides is not always easy because of many different types and settings of the equipment such as the microscopes and digital cameras. In this study, we developed a photomicrography technique that could acquire consistent images of pathology slides. The neutral density (ND) filter was attached to a transparent glass slide as a reference slide, photographed using consistent settings, and acquired images that harbored all of the areas of gray, white, and black. In the same way, the slide was replaced by the actual pathology slide, and photomicrographed. To simulate different light environment, the above photographic session was repeated using two different light intensities and microscopes. A graphic program was used to adjust levels of the reference slide images and this leveling, or calibration, was saved as a file for each. This file for leveling process was applied to actual subsequent photomicrographic images. The same sites of noncalibrated and calibrated images of the pathology slide were calculated into CIELAB or CIE L*a*b* coordinates. Then, the color differences (ΔE*ab) were calculated. As results, in the study using a 50% transmittance ND filter, two original different images were made nearly identical to the unaided eye, especially in two-point (white and gray) and three-point (black, white, and gray) leveling. In comparison of different light intensities, the ΔE*ab of the selected area was 0.9 in two-point leveling. Between different microscopes, 10.7 of ΔE*ab was the smallest value in three-point leveling. This method would be helpful for acquiring consistent photomicrographic images of pathology slides.

  3. Particle filter based on iterated importance density function and parallel resampling

    Institute of Scientific and Technical Information of China (English)

    武勇; 王俊; 曹运合

    2015-01-01

    The design, analysis and parallel implementation of particle filter (PF) were investigated. Firstly, to tackle the particle degeneracy problem in the PF, an iterated importance density function (IIDF) was proposed, where a new term associating with the current measurement information (CMI) was introduced into the expression of the sampled particles. Through the repeated use of the least squares estimate, the CMI can be integrated into the sampling stage in an iterative manner, conducing to the greatly improved sampling quality. By running the IIDF, an iterated PF (IPF) can be obtained. Subsequently, a parallel resampling (PR) was proposed for the purpose of parallel implementation of IPF, whose main idea was the same as systematic resampling (SR) but performed differently. The PR directly used the integral part of the product of the particle weight and particle number as the number of times that a particle was replicated, and it simultaneously eliminated the particles with the smallest weights, which are the two key differences from the SR. The detailed implementation procedures on the graphics processing unit of IPF based on the PR were presented at last. The performance of the IPF, PR and their parallel implementations are illustrated via one-dimensional numerical simulation and practical application of passive radar target tracking.

  4. Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

    2009-07-01

    The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

  5. Investigation of mud density and weighting materials effect on drilling fluid filter cake properties and formation damage

    Science.gov (United States)

    Fattah, K. A.; Lashin, A.

    2016-05-01

    Drilling fluid density/type is an important factor in drilling and production operations. Most of encountered problems during rotary drilling are related to drilling mud types and weights. This paper aims to investigate the effect of mud weight on filter cake properties and formation damage through two experimental approaches. In the first approach, seven water-based drilling fluid samples with same composition are prepared with different densities (9.0-12.0 lb/gal) and examined to select the optimum mud weight that has less damage. The second approach deals with investigating the possible effect of the different weighting materials (BaSO4 and CaCO3) on filter cake properties. High pressure/high temperature loss tests and Scanning Electron Microscopy (SEM) analyses were carried out on the filter cake (two selected samples). Data analysis has revealed that mud weigh of 9.5 lb/gal has the less reduction in permeability of ceramic disk, among the seven used mud densities. Above 10.5 ppg the effect of the mud weight density on formation damage is stabilized at constant value. Fluids of CaCO3-based weighting material, has less reduction in the porosity (9.14%) and permeability (25%) of the filter disk properties than the BaSO4-based fluid. The produced filter cake porosity increases (from 0.735 to 0.859) with decreasing of fluid density in case of drilling samples of different densities. The filtration loss tests indicated that CaCO3 filter cake porosity (0.52) is less than that of the BaSO4 weighted material (0.814). The thickness of the filter cake of the BaSO4-based fluid is large and can cause some problems. The SEM analysis shows that some major elements do occur on the tested samples (Ca, Al, Si, and Ba), with dominance of Ca on the expense of Ba for the CaCO3 fluid sample and vice versa. The less effect of 9.5 lb/gal mud sample is reflected in the well-produced inter-particle pore structure and relatively crystal size. A general recommendation is given to

  6. Implicit filtered PN for high-energy density thermal radiation transport using discontinuous Galerkin finite elements

    Science.gov (United States)

    Laboure, Vincent M.; McClarren, Ryan G.; Hauck, Cory D.

    2016-09-01

    In this work, we provide a fully-implicit implementation of the time-dependent, filtered spherical harmonics (FPN) equations for non-linear, thermal radiative transfer. We investigate local filtering strategies and analyze the effect of the filter on the conditioning of the system, showing in particular that the filter improves the convergence properties of the iterative solver. We also investigate numerically the rigorous error estimates derived in the linear setting, to determine whether they hold also for the non-linear case. Finally, we simulate a standard test problem on an unstructured mesh and make comparisons with implicit Monte Carlo (IMC) calculations.

  7. Implicit Filtered PN for High-Energy Density Thermal Radiation Transport using Discontinuous Galerkin Finite Elements

    CERN Document Server

    Laboure, Vincent M; Hauck, Cory D

    2016-01-01

    In this work, we provide a fully-implicit implementation of the time-dependent, filtered spherical harmonics (FPN) equations for non-linear, thermal radiative transfer. We investigate local filtering strategies and analyze the effect of the filter on the conditioning of the system in the streaming limit, showing in particular that the filter improves the convergence properties of the iterative solver. We also investigate numerically the rigorous error estimates derived in the linear setting, to determine whether they hold also for the non-linear case. Finally, we simulate a standard test problem on an unstructured mesh and make comparisons with implicit Monte-Carlo (IMC) calculations.

  8. Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method.

    Science.gov (United States)

    Saito, Masatoshi

    2009-08-01

    Dual-energy computed tomography (DECT) has the potential for measuring electron density distribution in a human body to predict the range of particle beams for treatment planning in proton or heavy-ion radiotherapy. However, thus far, a practical dual-energy method that can be used to precisely determine electron density for treatment planning in particle radiotherapy has not been developed. In this article, another DECT technique involving a balanced filter method using a conventional x-ray tube is described. For the spectral optimization of DECT using balanced filters, the author calculates beam-hardening error and air kerma required to achieve a desired noise level in electron density and effective atomic number images of a cylindrical water phantom with 50 cm diameter. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimized parameters were applied to cases with different phantom diameters ranging from 5 to 50 cm for the calculations. The author predicts that the optimal combination of tube voltages would be 80 and 140 kV with Tb/Hf and Bi/Mo filter pairs for the 50-cm-diameter water phantom. When a single phantom calibration at a diameter of 25 cm was employed to cover all phantom sizes, maximum absolute beam-hardening errors were 0.3% and 0.03% for electron density and effective atomic number, respectively, over a range of diameters of the water phantom. The beam-hardening errors were 1/10 or less as compared to those obtained by conventional DECT, although the dose was twice that of the conventional DECT case. From the viewpoint of beam hardening and the tube-loading efficiency, the present DECT using balanced filters would be significantly more effective in measuring the electron density than the conventional DECT. Nevertheless, further developments of low-exposure imaging technology should be necessary as well as x-ray tubes with higher outputs to apply DECT coupled with the

  9. New decision-based trimmed median filter for high-density salt-and-pepper noise removal in images

    Science.gov (United States)

    Vijaykumar, Vaithiyam Rengarajan; Santhanamari, Guru

    2014-05-01

    A new switching-based trimmed median filter to remove high-density salt-and-pepper noise in digital images is proposed. Initially, a 3×3 sliding window is applied on each pixel in the noisy image. The minimum- and maximum-intensity values are trimmed, and the noisy pixels are detected based on the predefined threshold value. In the filtering stage, the noisy pixels are replaced by median value of uncorrupted pixels in the trimmed array. At very high noise density, if all the pixels in the sliding window are corrupted, then the proposed algorithm replaces noisy pixels by the midpoint of recently processed pixels. The experimental results for various test images show that the performance of the proposed algorithm is superior to the existing algorithms, namely SMF, WMF, CWMF, AMF, DBA, and MDBUTMF in terms of visual quality and edge preservation, even at noise levels as high as 95%.

  10. Density changes with substrate negative bias for ta-C films deposited by filter cathode vacuum arc

    Institute of Scientific and Technical Information of China (English)

    TAN Man-lin; ZHU Jia-qi; HAN Jie-cai; MENG Song-he

    2004-01-01

    Specular X-ray reflectivity (XRR) measurements were used to study the density and cross-section information of tetrahedral amorphous carbon (ta-C) films deposited by filter cathode vacuum arc(FCVA) system at different substrate bias. According to the correlation between density and substrate negative bias, it is found that the value of density reaches a maximum at -80 V bias. As the substrate bias increases or decreases, the density tends to lower gradually. Based on the density of diamond and graphite, sp3 bonding ratio of ta-C films was obtained from their corresponding density according to a simple equation between the two. And a similar parabolic variation was observed for ta-C films with the sp3 content changes with substrate negative bias. The mechanical properties such as hardness and elastic modulus were also measured and compared with the corresponding density for ta-C films. From the distribution of data points, a linear proportional correlation between them was found, which shows that the density is a critical parameter to characterize the structure variation for ta-C films.

  11. Effects of Ammonia and Density on Filtering of Commensal and Pathogenic Escherichia coli by the Cladoceran Daphnia magna.

    Science.gov (United States)

    Nørgaard, Louise Solveig; Roslev, Peter

    2016-12-01

    Grazing by cladocerans can reduce the survival of enteric bacteria associated with fecal pollution. This study examined the potential of Daphnia magna to filter commensal and pathogenic Escherichia coli of human origin. Grazing on commensal and pathogenic bacteria was comparable, but slightly greater at 20 compared to 15 and 25°C. Filtering activity was strongly dependent on D. magna and E. coli densities at environmentally relevant bacterial concentrations. Maximum feeding rates were >10(7) cells h(-1) daphnid(-1), clearance rates were 1-6 mL h(-1) daphnid(-1), and filtering was independent of bacterial cell sizes between 0.7 and 1.8 µm. Filtering and ingestion of E. coli by D. magna was susceptible to acute inhibition by unionized ammonia with a 24 h EC50 of 0.18 mg L(-1) NH3-N, and a LOEC of 0.09 mg L(-1) NH3-N. The study indicated that biological and chemical constraints should be considered when applying Daphnia for attenuation of fecal pollution.

  12. Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes

    Directory of Open Access Journals (Sweden)

    Jones Sophie

    2012-08-01

    Full Text Available Abstract Background Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored. Methods Three gametocyte dilutions: 10/μL, 1.0/μL and 0.1/μL were spotted onto Whatman™ 903 Protein Saver Cards, FTA Classic Cards and 3MM filter papers that were stored under frozen, cold chain or tropical conditions for up to 13 weeks . RNA was extracted, then detected by quantitative nucleic acid sequence-based amplification (QT-NASBA and reverse-transcriptase PCR (RT-PCR. Results Successful gametocyte detection was more frequently observed from the Whatman 903 Protein Saver Card compared to the Whatman FTA Classic Card, by both techniques (p  Conclusions This study indicates the Whatman 903 Protein Saver Card is better for Pfs25 mRNA sampling compared to the Whatman FTA Classic Card, and that the Whatman 3MM filter paper may prove to be a satisfactory cheaper option for Pfs25 mRNA sampling. When appropriately dried, filter papers provide a useful approach to Pfs25 mRNA sampling, especially in settings where storage in RNA-protecting buffer is not possible.

  13. Gene expression profiling in human peripheral blood mononuclear cells using high-density filter-based cDNA microarrays.

    Science.gov (United States)

    Walker, J; Rigley, K

    2000-05-26

    Microarray technology has provided the ability to analyse the expression profiles for thousands of genes in parallel. The need for highly specialised equipment to use certain types of microarrays has restricted the application of this technology to a small number of dedicated laboratories. High-density filter-based cDNA microarrays provide a low-cost option for performing high-throughput gene expression analysis. We have used a model system in which filter-based cDNA microarrays representing over 4000 known human genes were used to monitor the kinetics of gene expression in human peripheral blood mononuclear cells (PBMCs) stimulated with phytohaemagluttinin (PHA). Using software-based cluster analysis, we identified 104 genes that altered in expression levels in response to PHA stimulation of PBMCs and showed that there was a considerable overlap between genes with similar temporal expression profiles and similar functional roles. Comparison of microarray quantitation with quantitative PCR showed almost identical expression profiles for a number of genes. Coupled with the fact that our findings are in agreement with a large number of independent observations, we conclude that the use of filter-based cDNA microarrays is a valid and accurate method for high-throughput gene expression profiling.

  14. CPHD filter derivation for extended targets

    CERN Document Server

    Orguner, Umut

    2010-01-01

    This document derives the CPHD filter for extended targets. Only the update step is derived here. Target generated measurements, false alarms and prior are all assumed to be independent identically distributed cluster processes. We also prove here that the derived CPHD filter for extended targets reduce to PHD filter for extended targets and CPHD filter for standard targets under suitable assumptions.

  15. Combining Predictive Densities using Nonlinear Filtering with Applications to US Economics Data

    NARCIS (Netherlands)

    M. Billio (Monica); R. Casarin (Roberto); F. Ravazzolo (Francesco); H.K. van Dijk (Herman)

    2011-01-01

    textabstractWe propose a multivariate combination approach to prediction based on a distributional state space representation of the weights belonging to a set of Bayesian predictive densities which have been obtained from alternative models. Several specifications of multivariate time-varying weigh

  16. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-12-01

    Full Text Available Report of PhD Dissertations. Guido Antonioli Conservator pacis et iustitie. La signoria di Taddeo Pepoli a Bologna (1337-1347, Tesi di dottorato di ricerca in Filologia romanza e cultura medievale (XIII ciclo, Università degli Studi di Bologna, 2001   Elisabetta Filippini «In vassallatico episcopi permanere debent». Rapporti vassallatici e concessioni beneficiali dei vescovi di Cremona fra X e XIII secolo, Tesi di dottorato di Ricerca in Storia Medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2003   Marco Meschini, Innocenzo III e il "negotium pacis et fidei" in Linguadoca tra il 1198 e il 1215, Tesi di dottorato di ricerca in Storia medievale, Università Cattolica del Sacro Cuore, 2003   Fabrizio Ricciardelli The Politics of Exclusion in Florence (1215-1434, thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, University of Warwick, Department of History, April 2003 Renata Salvarani Baptizare pueros et decimas dare. Cura delle anime, strutturazione ecclesiastica e organizzazione delle campagne in area gardesana fra VIII e XIII secolo (diocesi di Brescia, Verona, Mantova e Trento, Tesi di dottorato in Storia medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2002-2003   Vito Sibilio Le parole della prima crociata, Tesi di dottorato di ricerca in Storia dei centri delle vie e della cultura dei pellegrinaggi nel medioevo euromediterraneo, Università degli studi di Lecce, 2003

  17. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2000-06-01

    Full Text Available Report of PhD Dissertations.   Miguel Calleja Puerta El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000   Adele Cilento Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000   Amedeo De Vincentiis Firenze e i signori. Sperimentazioni istituzionali e modelli di regime nelle signorie fiorentine degli Angioini (fine XIII - metà XIV secolo, Tesi di dottorato di ricerca in Storia medioevale (XI ciclo, Università degli Studi di Milano, 1999   Marco Folin Il sistema politico di un antico Stato italiano: i ducati estensi nella prima Età moderna (1452-1598, Tesi di dottorato di ricerca in Storia, Scuola Normale superiore di Pisa, 2000   Barbara Frale Guardiani del Santuario. Le radici orientali del processo contro l’ordine del Tempio (1128 - 1314, Tesi di dottorato di ricerca in Storia sociale d’Europa (XI ciclo, Università "Ca’ Foscari" di Venezia, 2000

  18. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-06-01

    Full Text Available Reporto of PhD Dissertations.   Mario Dalle Carbonare Società, potere e clientele nell’Irlanda altomedievale (secoli V-IX, Tesi di dottorato di ricerca in Storia sociale europea, Università "Ca' Foscari" di Venezia, 2003 Vieri Mazzoni La legislazione antighibellina e la politica oligarchica della Parte Guelfa di Firenze nel secondo Trecento (1347-1378, Tesi di dottorato di ricerca in Storia Medievale (ciclo XII, Università degli Studi di Firenze   Alma Poloni Pisa dalle origini del movimento popolare alla discesa di Ludovico il Bavaro. I gruppi dirigenti cittadini tra continuità e trasformazione, Tesi di dottorato di ricerca in Storia dell'Europa nel medioevo, Università degli studi di Pisa, 2003   Andrea Puglia Potere marchionale, amministrazione del territorio, società locali dalla morte di Ugo di Tuscia a Guelfo VI di Baviera (1001-1160, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Milano, 2003

  19. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2010-06-01

    Full Text Available Report of PhD dissertations. Andrea Brugnoli Una storia locale: l’organizzazione del territorio veronese nel medioevo: trasformazioni della realtà e schemi notarili (IX-metà XII secolo, Tesi di dottorato di ricerca in Scienze Storiche e Antropologiche (XXII ciclo, Università degli Studi di Verona, 2010   Luca Filangieri Famiglie e gruppi dirigenti a Genova (secoli XII-metà XIII, Tesi di dottorato di ricerca in Storia medievale (XXII ciclo, Università degli Studi di Firenze, 2010   Jakub Kujawi ski Wernakularna kolekcja historiograficzna z rękopisu francuskiego nr 688 z Biblioteki Narodowej w Paryżu. Studium źródłoznawcze (La raccolta dei volgarizzamenti delle opere storiografiche nel manoscritto francese 688 della Biblioteca Nazionale di Parigi, Tesi di dottorato, Università “Adam Mickiewicz”, Facoltà di Storia, Pozna, a.a. 2009/2010   Marta Longhi I signori “de Radicata”. Strategie di affermazione familiare e patrimoniale nel Piemonte dei secoli XII-XIV, Tesi di dottorato di ricerca in Istituzioni, Società, Religioni dal Tardo Antico alla fine del Medioevo (XX ciclo, Università di Torino, 2008

  20. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-06-01

    Full Text Available Report of PhD Dissertations. Francesco Barone Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Laura Berti Ceroni Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.   Marco Bicchierai Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004   Emanuela Garimberti Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Lorenzo Tanzini Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Stefania Tarquini Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

  1. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  2. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  3. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-06-01

    Full Text Available Report of PhD Dissertations. Federica Cengarle Le investiture feudali di Filippo Maria Visconti (1412-1447, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Milano, 2005 Silvia Coazzin Liberi domini totius castri. L'aristocrazia rurale "minore" nel Senese e nella Toscana meridionale. Forme di egemonia, assetto sociale e patrimoniale di lignaggi, famiglie e gruppi consortili di castello (secc. XI-XIV, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Maria Elena Cortese Signori e castelli. Famiglie aristocratiche, dominati signorili e trasformazioni insediative nel comitatus fiorentino (fine X-metà XII secolo, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Patrizia Meli Gabriele Malaspina marchese di Fosdinovo: il condottiero ed il politico, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Federica Pessotto La Morea franca. Economia e istituzioni tra Oriente e Occidente nei secoli XIII e XIV, Tesi di dottorato di ricerca in Istituzioni, Società e Religioni dal Tardoantico alla fine del Medioevo, Università degli studi di Torino, 2003 Lorenzo Pubblici Dal Caucaso al Mar d’Azov. L’impatto dell’invasione mongola nella Caucasia fra nomadismo e civiltà sedentaria (1204-1395, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 [01/05] Riccardo Rao "Comunia". Risorse collettive e patrimoniali dei maggiori comuni subalpini (secoli XII - inizio XIV, Tesi di dottorato di ricerca in Storia medioevale, Università degli Studi di Milano, 2005 Alessandro Soddu Feudalesimo e potere signorile in Sardegna nei secoli XI-XIV.  La signoria territoriale dei Malaspina, Tesi di dottorato di ricerca in Storia, Università "Pompeu Fabra" di Barcellona, 2004

  4. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2002-06-01

    Full Text Available Report of PhD dissertation. Laura Baietto Una politica per le città. Rapporti fra papato, vescovi e comuni nell'Italia centro-settentrionale da Innocenzo III a Gregorio IX, Tesi di dottorato di ricerca in Storia Medievale, Università degli Studi di Torino, 2002   Giuseppe Banfo Compresenze e sovrapposizioni di poteri territoriali di qualità diversa tra X e XIII: il caso del basso Monferrato, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2002   Francesca Dell'Acqua La vetrata tra l'età tardo imperiale e l'altomedioevo: le fonti, l'archeologia, Tesi di Perfezionamento in Storia dell'Arte Medievale, Scuola Normale Superiore di Pisa, 2001   Primo Giovanni Embriaco I vescovi di Albenga e gli sviluppi signorili nella Liguria occidentale (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2001   Antonella Ghignoli Documenti e proprietà altomedievali. Fondamenti e problemi dell'esegesi storica delle fonti documentarie nello specchio della tradizione delle carte pisane dei secoli VIII-XI, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Vito Loré Espansione monastica e mutamenti politici. La Trinità di Cava nei suoi rapporti con i sovrani longobardi e normanni e con l'aristocrazia territoriale. Secoli XI-XII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Rosaria Stracuzzi Messina nel '400, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Palermo, 2001   Stefania Tamburini Le "portate" ecclesiastiche nel piviere di San Giovanni in Firenze nel 1427. Spunti per una riflessione sul patrimonio ecclesiastico della diocesi fiorentina,Tesi di dottorato di ricerca in Storia e informatica, Università degli Studi di Bologna, 2001

  5. Progress Toward Affordable High Fidelity Combustion Simulations Using Filtered Density Functions for Hypersonic Flows in Complex Geometries

    Science.gov (United States)

    Drozda, Tomasz G.; Quinlan, Jesse R.; Pisciuneri, Patrick H.; Yilmaz, S. Levent

    2012-01-01

    Significant progress has been made in the development of subgrid scale (SGS) closures based on a filtered density function (FDF) for large eddy simulations (LES) of turbulent reacting flows. The FDF is the counterpart of the probability density function (PDF) method, which has proven effective in Reynolds averaged simulations (RAS). However, while systematic progress is being made advancing the FDF models for relatively simple flows and lab-scale flames, the application of these methods in complex geometries and high speed, wall-bounded flows with shocks remains a challenge. The key difficulties are the significant computational cost associated with solving the FDF transport equation and numerically stiff finite rate chemistry. For LES/FDF methods to make a more significant impact in practical applications a pragmatic approach must be taken that significantly reduces the computational cost while maintaining high modeling fidelity. An example of one such ongoing effort is at the NASA Langley Research Center, where the first generation FDF models, namely the scalar filtered mass density function (SFMDF) are being implemented into VULCAN, a production-quality RAS and LES solver widely used for design of high speed propulsion flowpaths. This effort leverages internal and external collaborations to reduce the overall computational cost of high fidelity simulations in VULCAN by: implementing high order methods that allow reduction in the total number of computational cells without loss in accuracy; implementing first generation of high fidelity scalar PDF/FDF models applicable to high-speed compressible flows; coupling RAS/PDF and LES/FDF into a hybrid framework to efficiently and accurately model the effects of combustion in the vicinity of the walls; developing efficient Lagrangian particle tracking algorithms to support robust solutions of the FDF equations for high speed flows; and utilizing finite rate chemistry parametrization, such as flamelet models, to reduce

  6. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-12-01

    Full Text Available Report of PhD Dissertations. Massimo Della Misericordia Divenire comunità. Comuni rurali, poteri signorili, identità sociali in Valtellina e nella montagna lombarda nel tardo medioevo, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Torino, 2003   Mariano Dell’Omo Il monastero di S. Liberatore alla Maiella centro dell’irradiazione di Montecassino nell’Abruzzo medievale e moderno. Contributo alla storia dell’organizzazione patrimoniale e della civiltà monastica cassinese nell’Italia centrale attraverso i documenti di S. Liberatore conservati nell’Archivio di Montecassino. Introduzione storica, paleografica e archivistica. Edizione dei documenti più antichi (†798-1000 e regesti di quelli posteriori (1005-1735, Tesi di dottorato in Storia Ecclesiastica, Facoltà di Storia Ecclesiastica, Pontificia Università Gregoriana di Roma,  2004   Giulia Lorenzoni Conquistare e governare la città. Forme di potere e istituzioni nel primo anno della signoria viscontea a Bologna (ottobre 1350-novembre 1351, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Bologna, 2004   Federica Monteleone Il viaggio di Carlo Magno in Terra Santa. Un’esperienza di pellegrinaggio nella tradizione europea occidentale, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo   Francesca Pucci Donati Fra teorie mediche e pratica quotidiana: i calendari dietetici dell’Occidente latino altomedievale (secoli IX-XI, Tesi di dottorato di ricerca in Storia medievale (XV ciclo, Università degli studi di Bologna, 2004 Alberto Ricciardi L’Epistolario di Lupo di Ferrières come fonte per la storia degli intellettuali nell’età di Carlo il Calvo, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Francesco Paolo Terlizzi I trattati dell'Anonimo Normanno: ricerche di ecclesiologia, Tesi

  7. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    Science.gov (United States)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  8. The Oxygen Sensor PHD2 Controls Dendritic Spines and Synapses via Modification of Filamin A

    Directory of Open Access Journals (Sweden)

    Inmaculada Segura

    2016-03-01

    Full Text Available Neuronal function is highly sensitive to changes in oxygen levels, but how hypoxia affects dendritic spine formation and synaptogenesis is unknown. Here we report that hypoxia, chemical inhibition of the oxygen-sensing prolyl hydroxylase domain proteins (PHDs, and silencing of Phd2 induce immature filopodium-like dendritic protrusions, promote spine regression, reduce synaptic density, and decrease the frequency of spontaneous action potentials independently of HIF signaling. We identified the actin cross-linker filamin A (FLNA as a target of PHD2 mediating these effects. In normoxia, PHD2 hydroxylates the proline residues P2309 and P2316 in FLNA, leading to von Hippel-Lindau (VHL-mediated ubiquitination and proteasomal degradation. In hypoxia, PHD2 inactivation rapidly upregulates FLNA protein levels because of blockage of its proteasomal degradation. FLNA upregulation induces more immature spines, whereas Flna silencing rescues the immature spine phenotype induced by PHD2 inhibition.

  9. Chemiluminescent detection of sequential DNA hybridizations to high-density, filter-arrayed cDNA libraries: a subtraction method for novel gene discovery.

    Science.gov (United States)

    Guiliano, D; Ganatra, M; Ware, J; Parrot, J; Daub, J; Moran, L; Brennecke, H; Foster, J M; Supali, T; Blaxter, M; Scott, A L; Williams, S A; Slatko, B E

    1999-07-01

    A chemiluminescent approach for sequential DNA hybridizations to high-density filter arrays of cDNAs, using a biotin-based random priming method followed by a streptavidin/alkaline phosphatase/CDP-Star detection protocol, is presented. The method has been applied to the Brugia malayi genome project, wherein cDNA libraries, cosmid and bacterial artificial chromosome (BAC) libraries have been gridded at high density onto nylon filters for subsequent analysis by hybridization. Individual probes and pools of rRNA probes, ribosomal protein probes and expressed sequence tag probes show correct specificity and high signal-to-noise ratios even after ten rounds of hybridization, detection, stripping of the probes from the membranes and rehybridization with additional probe sets. This approach provides a subtraction method that leads to a reduction in redundant DNA sequencing, thus increasing the rate of novel gene discovery. The method is also applicable for detecting target sequences, which are present in one or only a few copies per cell; it has proven useful for physical mapping of BAC and cosmid high-density filter arrays, wherein multiple probes have been hybridized at one time (multiplexed) and subsequently "deplexed" into individual components for specific probe localizations.

  10. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  11. Low-dislocation-density epitatial layers grown by defect filtering by self-assembled layers of spheres

    Science.gov (United States)

    Wang, George T.; Li, Qiming

    2013-04-23

    A method for growing low-dislocation-density material atop a layer of the material with an initially higher dislocation density using a monolayer of spheroidal particles to bend and redirect or directly block vertically propagating threading dislocations, thereby enabling growth and coalescence to form a very-low-dislocation-density surface of the material, and the structures made by this method.

  12. Increased EPO Levels Are Associated With Bone Loss in Mice Lacking PHD2 in EPO-Producing Cells.

    Science.gov (United States)

    Rauner, Martina; Franke, Kristin; Murray, Marta; Singh, Rashim Pal; Hiram-Bab, Sahar; Platzbecker, Uwe; Gassmann, Max; Socolovsky, Merav; Neumann, Drorit; Gabet, Yankel; Chavakis, Triantafyllos; Hofbauer, Lorenz C; Wielockx, Ben

    2016-10-01

    The main oxygen sensor hypoxia inducible factor (HIF) prolyl hydroxylase 2 (PHD2) is a critical regulator of tissue homeostasis during erythropoiesis, hematopoietic stem cell maintenance, and wound healing. Recent studies point toward a role for the PHD2-erythropoietin (EPO) axis in the modulation of bone remodeling, even though the studies produced conflicting results. Here, we used a number of mouse strains deficient of PHD2 in different cell types to address the role of PHD2 and its downstream targets HIF-1α and HIF-2α in bone remodeling. Mice deficient for PHD2 in several cell lineages, including EPO-producing cells, osteoblasts, and hematopoietic cells (CD68:cre-PHD2(f/f) ) displayed a severe reduction of bone density at the distal femur as well as the vertebral body due to impaired bone formation but not bone resorption. Importantly, using osteoblast-specific (Osx:cre-PHD2(f/f) ) and osteoclast-specific PHD2 knock-out mice (Vav:cre- PHD2(f/f) ), we show that this effect is independent of the loss of PHD2 in osteoblast and osteoclasts. Using different in vivo and in vitro approaches, we show here that this bone phenotype, including the suppression of bone formation, is directly linked to the stabilization of the α-subunit of HIF-2, and possibly to the subsequent moderate induction of serum EPO, which directly influenced the differentiation and mineralization of osteoblast progenitors resulting in lower bone density. Taken together, our data identify the PHD2:HIF-2α:EPO axis as a so far unknown regulator of osteohematology by controlling bone homeostasis. Further, these data suggest that patients treated with PHD inhibitors or EPO should be monitored with respect to their bone status. © 2016 American Society for Bone and Mineral Research.

  13. Turbulent-PSO-Based Fuzzy Image Filter With No-Reference Measures for High-Density Impulse Noise.

    Science.gov (United States)

    Chou, Hsien-Hsin; Hsu, Ling-Yuan; Hu, Hwai-Tsu

    2013-02-01

    Digital images are often corrupted by impulsive noise during data acquisition, transmission, and processing. This paper presents a turbulent particle swarm optimization (PSO) (TPSO)-based fuzzy filtering (or TPFF for short) approach to remove impulse noise from highly corrupted images. The proposed fuzzy filter contains a parallel fuzzy inference mechanism, a fuzzy mean process, and a fuzzy composition process. To a certain extent, the TPFF is an improved and online version of those genetic-based algorithms which had attracted a number of works during the past years. As the PSO is renowned for its ability of achieving success rate and solution quality, the superiority of the TPFF is almost for sure. In particular, by using a no-reference Q metric, the TPSO learning is sufficient to optimize the parameters necessitated by the TPFF. Therefore, the proposed fuzzy filter can cope with practical situations where the assumption of the existence of the "ground-truth" reference does not hold. The experimental results confirm that the TPFF attains an excellent quality of restored images in terms of peak signal-to-noise ratio, mean square error, and mean absolute error even when the noise rate is above 0.5 and without the aid of noise-free images.

  14. Urbanism PhD Research 2008 - 2010

    NARCIS (Netherlands)

    Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çalışkan, O.; Tan, E.R.; Wang, C.-Y.; Zhou, J.

    2009-01-01

    To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the Departme

  15. A PHD in histone language

    Science.gov (United States)

    Chandrika, Nulu Naga Prafulla; Sundaravelpandian, Kalaipandian; Schmidt, Wolfgang

    2013-01-01

    Post-translational modifications of core histones are important for various DNA-templated processes such as transcription and repair. We recently reported that the ALFIN LIKE 6 (AL6) gene, identified in a forward genetic screen, is critical for phosphate deficiency-induced root hair formation and several other processes associated with the regulation of cellular phosphate homeostasis. AL6 contains a Plant Homeo Domain (PHD) finger that can bind to trimethylated lysine 4 of histone H3 (H3K4me3). Homozygous mutants defective in AL6 expression form very short root hairs under phosphate-deficient conditions, presumably caused by altered expression of putative primary and secondary down-stream targets of AL6. In this Addendum, we speculate about possible roles of AL6, H3K4 trimethylation and other chromatin modifications in the adaptation of plants to low phosphate availability. PMID:23531693

  16. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  17. On an ESFADOF edge-filter for a range resolved Brillouin-lidar: The high vapor density and high pump intensity regime

    Science.gov (United States)

    Popescu, A.; Walther, T.

    2010-03-01

    The temperature profile in the upper ocean mixed layer is of great interest for oceanography, weather forecast and climate studies—especially regarding the strong coupling between the atmosphere and the ocean. A lidar system based on Brillouin-scattering can provide such data over an extended region of the ocean. In this paper we report on studies of an excited-state Faraday anomalous dispersion optical (ESFADOF) edge-filter that, when employed as a receiver in a Brillouin-lidar, will enable range-resolved remote measurements from mobile platforms. We focus on the transmission of such a filter operating on the 5 P 3/2→8 D 5/2 Rb transition (543.30 nm), and its dependence on the vapor density in the high pump intensity regime. Due to quenching processes such as energy-pooling enhanced by nonlinear radiation trapping, as well as plasma formation, a limit on the lower ESFADOF level number density exists. Beyond this threshold the achievable ESFADOF transmission is limited to a few percent. However, our studies show for the first time measured ESFADOF spectra with steep transmission edges with a transmission change of 15% within a few gigahertz.

  18. ATLAS PhD Grant Scheme

    CERN Multimedia

    2016-01-01

    In this #CERNandSociety video, the 3 PhD students, awarded the ATLAS PhD Grant in 2015, talk about their research work within the ATLAS Collaboration and how this experience has shaped their future. Find out more about the ATLAS PhD Grant Scheme: cern.ch/ATLASPhDGrant This programme is just one of the many #CERNandSociety projects at CERN. Find out more and how you can be involved: http://cern.ch/go/pBt7

  19. Brenda K. Edwards, PhD

    Science.gov (United States)

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  20. Biomedical PhD education - an international perspective

    DEFF Research Database (Denmark)

    Mulvany, Michael J.

    2013-01-01

    The PhD, otherwise known as the doctor of philosophy or Dr. Phil., is an internationally recognized degree, indicating that the PhD graduate has received training in research under supervision. Traditionally, the PhD was the route to an academic career, with most successful PhD graduates receivin...

  1. What PhD students really want

    CERN Document Server

    Mao, Minnie

    2010-01-01

    The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is e...

  2. A New Switching-Based Median Filtering Scheme and Algorithm for Removal of High-Density Salt and Pepper Noise in Images

    Directory of Open Access Journals (Sweden)

    Jayaraj V

    2010-01-01

    Full Text Available A new switching-based median filtering scheme for restoration of images that are highly corrupted by salt and pepper noise is proposed. An algorithm based on the scheme is developed. The new scheme introduces the concept of substitution of noisy pixels by linear prediction prior to estimation. A novel simplified linear predictor is developed for this purpose. The objective of the scheme and algorithm is the removal of high-density salt and pepper noise in images. The new algorithm shows significantly better image quality with good PSNR, reduced MSE, good edge preservation, and reduced streaking. The good performance is achieved with reduced computational complexity. A comparison of the performance is made with several existing algorithms in terms of visual and quantitative results. The performance of the proposed scheme and algorithm is demonstrated.

  3. Mathematical modeling of separated two-phase turbulent reactive flows using a filtered mass density function approach for large eddy simulation

    Science.gov (United States)

    Carrara, Mark David

    2006-04-01

    The overall objective of this dissertation is the development of a modeling and simulation approach for turbulent two-phase chemically reacting flows. A new full velocity-scalar filtered mass density function (FMDF) formulation for large eddy simulation (LES) of a separated two-phase flow is developed. In this formulation several terms require modeling that include important conditionally averaged phase-coupling terms (PCT). To close the PCT a new derivation of the local instantaneous two-phase equations is presented and important identities are derived relating the PCT to surface averages. The formulation is then applied for two particle laden flow cases and solved using a full particle based Monte-Carlo numerical solution procedure. The first case is a temporally developing counter-current mixing layer dilutely seeded with evaporating water droplets. Validation studies reveal excellent agreement of the full particle method to previous hybrid FDF studies and direct numerical simulations for single-phase flows. One-way coupled simulations reveal that the overall dispersion is maximized with unity Stokes number droplets. Two-way coupled simulations reveal the advantages of two FDF approaches where the subgrid variation of droplet properties are explicitly taken into account. Comparisons of the fully-coupled FDF approach are compared to more approximate means of determining phase-coupling based on filtered properties and local and compounded global errors are assessed. The second case considered is the combustion aluminum particles. A new mechanistic model for the ignition and combustion of aluminum particulate is developed that accounts for unsteady heating, melting, heterogeneous surface reactions (HSR) and quasi-steady burning. Results of this model agree well with experimental data for overall burn rates and ignition times. Two-phase simulations of aluminum particulate seeded mixing layer reveal the variations in flame radius resulting in local extinguishment

  4. Variational Bayesian labeled multi-Bernoulli filter with unknown sensor noise statistics

    Directory of Open Access Journals (Sweden)

    Qiu Hao

    2016-10-01

    Full Text Available It is difficult to build accurate model for measurement noise covariance in complex backgrounds. For the scenarios of unknown sensor noise variances, an adaptive multi-target tracking algorithm based on labeled random finite set and variational Bayesian (VB approximation is proposed. The variational approximation technique is introduced to the labeled multi-Bernoulli (LMB filter to jointly estimate the states of targets and sensor noise variances. Simulation results show that the proposed method can give unbiased estimation of cardinality and has better performance than the VB probability hypothesis density (VB-PHD filter and the VB cardinality balanced multi-target multi-Bernoulli (VB-CBMeMBer filter in harsh situations. The simulations also confirm the robustness of the proposed method against the time-varying noise variances. The computational complexity of proposed method is higher than the VB-PHD and VB-CBMeMBer in extreme cases, while the mean execution times of the three methods are close when targets are well separated.

  5. ATLAS PhD Grants 2015

    CERN Multimedia

    Marcelloni De Oliveira, Claudia

    2015-01-01

    ATLAS PHd Grants - We are excited to announce the creation of a dedicated grant scheme (thanks to a donation from Fabiola Gianotti and Peter Jenni following their award from the Fundamental Physics Prize foundation) to encourage young and high-caliber doctoral students in particle physics research (including computing for physics) and permit them to obtain world class exposure, supervision and training within the ATLAS collaboration. This special PhD Grant is aimed at graduate students preparing a doctoral thesis in particle physics (incl. computing for physics) to spend one year at CERN followed by one year support also at the home Institute.

  6. Sensor Fusion Based on an Integrated Neural Network and Probability Density Function (PDF) Dual Kalman Filter for On-Line Estimation of Vehicle Parameters and States.

    Science.gov (United States)

    Vargas-Melendez, Leandro; Boada, Beatriz L; Boada, Maria Jesus L; Gauchia, Antonio; Diaz, Vicente

    2017-04-29

    Vehicles with a high center of gravity (COG), such as light trucks and heavy vehicles, are prone to rollover. This kind of accident causes nearly 33 % of all deaths from passenger vehicle crashes. Nowadays, these vehicles are incorporating roll stability control (RSC) systems to improve their safety. Most of the RSC systems require the vehicle roll angle as a known input variable to predict the lateral load transfer. The vehicle roll angle can be directly measured by a dual antenna global positioning system (GPS), but it is expensive. For this reason, it is important to estimate the vehicle roll angle from sensors installed onboard in current vehicles. On the other hand, the knowledge of the vehicle's parameters values is essential to obtain an accurate vehicle response. Some of vehicle parameters cannot be easily obtained and they can vary over time. In this paper, an algorithm for the simultaneous on-line estimation of vehicle's roll angle and parameters is proposed. This algorithm uses a probability density function (PDF)-based truncation method in combination with a dual Kalman filter (DKF), to guarantee that both vehicle's states and parameters are within bounds that have a physical meaning, using the information obtained from sensors mounted on vehicles. Experimental results show the effectiveness of the proposed algorithm.

  7. Substrate removal kinetics in high-rate upflow anaerobic filters packed with low-density polyethylene media treating high-strength agro-food wastewaters.

    Science.gov (United States)

    Rajagopal, Rajinikanth; Torrijos, Michel; Kumar, Pradeep; Mehrotra, Indu

    2013-02-15

    The process kinetics for two upflow anaerobic filters (UAFs) treating high strength fruit canning and cheese-dairy wastewaters as feed were investigated. The experimental unit consisted of a 10-L (effective volume) reactor filled with low-density polyethylene media. COD removal efficiencies of about 80% were recorded at the maximum OLRs of 19 and 17 g COD L(-1) d(-1) for the fruit canning and cheese-dairy wastewaters, respectively. Modified Stover-Kincannon and second-order kinetic models were applied to data obtained from the experimental studies in order to determine the substrate removal kinetics. According to Stover-Kincannon model, U(max) and K(B) values were estimated as 109.9 and 109.7 g L(-1) d(-1) for fruit canning, and 53.5 and 49.7 g L(-1) d(-1) for cheese dairy wastewaters, respectively. The second order substrate removal rate k(2(s)) was found to be 5.0 and 1.93 d(-1) respectively for fruit canning and cheese dairy wastewaters. As both these models gave high correlation coefficients (R(2) = 98-99%), they could be used in predicting the behaviour or design of the UAF.

  8. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  9. What My Ph.D. Taught Me

    Science.gov (United States)

    Levenstein, Jessica

    2013-01-01

    The author started in the Ph.D. program in comparative literature at Princeton in 1992, a year after she graduated from college. She fell in love with mythology and the classical traditions and find herself teaching literature. In the remainder of her time at Princeton, she precepted for four or five more classes, got the chance to join the…

  10. Retention of prolyl hydroxylase PHD2 in the cytoplasm prevents PHD2-induced anchorage-independent carcinoma cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Jokilehto, Terhi [Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku (Finland); Turku Graduate School of Biomedical Sciences, Turku (Finland); Hoegel, Heidi [Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku (Finland); Heikkinen, Pekka [Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku (Finland); Turku Graduate School of Biomedical Sciences, Turku (Finland); Rantanen, Krista [Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku (Finland); Elenius, Klaus [Department of Oncology and Radiotherapy, University of Turku and Turku University Hospital, Turku (Finland); Department of Medical Biochemistry and Genetics, University of Turku and Turku University Hospital, Turku (Finland); Sundstroem, Jari [Department of Pathology, University of Turku and Turku University Hospital, Turku (Finland); Jaakkola, Panu M. [Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku (Finland); Department of Oncology and Radiotherapy, University of Turku and Turku University Hospital, Turku (Finland)

    2010-04-15

    Cellular oxygen tension is sensed by a family of prolyl hydroxylases (PHD1-3) that regulate the degradation of hypoxia-inducible factors (HIF-1{alpha} and -2{alpha}). The PHD2 isoform is considered as the main downregulator of HIF in normoxia. Our previous results have shown that nuclear translocation of PHD2 associates with poorly differentiated tumor phenotype implying that nuclear PHD2 expression is advantageous for tumor growth. Here we show that a pool of PHD2 is shuttled between the nucleus and the cytoplasm. In line with this, accumulation of wild type PHD2 in the nucleus was detected in human colon adenocarcinomas and in cultured carcinoma cells. The PHD2 isoforms showing high nuclear expression increased anchorage-independent carcinoma cell growth. However, retention of PHD2 in the cytoplasm inhibited the anchorage-independent cell growth. A region that inhibits the nuclear localization of PHD2 was identified and the deletion of the region promoted anchorage-independent growth of carcinoma cells. Finally, the cytoplasmic PHD2, as compared with the nuclear PHD2, less efficiently downregulated HIF expression. Forced HIF-1{alpha} or -2{alpha} expression decreased and attenuation of HIF expression increased the anchorage-independent cell growth. However, hydroxylase-inactivating mutations in PHD2 had no effect on cell growth. The data imply that nuclear PHD2 localization promotes malignant cancer phenotype.

  11. PhD Students' Work Conditions and Study Environment in University- and Industry-Based PhD Programmes

    Science.gov (United States)

    Kolmos, A.; Kofoed, L. B.; Du, X. Y.

    2008-01-01

    During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what…

  12. ATLAS PhD Grant Scholarship Programme

    CERN Multimedia

    Abha Eli Phoboo

    2014-01-01

    On 11 February, the first recipients of the ATLAS PhD Grant were presented with a certificate by the programme’s selection committee. The three scholars - Lailin Xu of China, Josefina Alconada of Argentina and Gagik Vardanyan of Armenia - were delighted at being able to continue their PhD programmes at CERN.   With certificates, from left: Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, from left: IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James Purvis. (Image: ATLAS/Claudia Marcelloni). Former ATLAS spokespersons Peter Jenni and Fabiola Gianotti started the fund with the Fundamental Physics Prize award money they received last year. Both have used the entirety of their prizes for educational and humanitarian programmes. "We wanted to do something for students who are working on ATLAS, in particular those who otherwise could not come here and actually see the detector they are working on,&am...

  13. PhD students share their work

    CERN Multimedia

    Joannah Caborn Wengler

    2012-01-01

    Last week, the second Doctoral Student Assembly gave students in the final stages of their PhD at CERN the chance to meet and present their work.   On 9 May, 24 students who are completing their PhD under the CERN Doctoral Student Programme were joined by their CERN supervisors and some of their university supervisors at an event organised by HR and the Technical Students Committee (TSC). After an address by the Director-General Rolf Heuer and short presentations by Ingrid Haug from HR and TSC Chair Stephan Russenschuck, the students presented their work in a poster session. Held in a packed Council Chamber, the event was a great opportunity for the doctoral students to get to know each other and to share their work in fields as diverse as radiation protection, computing, physics and engineering.

  14. PhD competences of food studies

    Directory of Open Access Journals (Sweden)

    Chelo Gonzalez-Martinez

    2014-10-01

    Full Text Available In European Higher Education, learning outcomes and competences have been used sometimes with different meanings and sometimes with the same meaning. But both terms have been more commonly used to refer to knowledge, understanding and abilities a student must demonstrate at the end of a learning experience.  Their use is a consequence of the paradigm shift of the Bologna Process to a learner centered education environment. The definition of standards of competences (or learning outcomes for the PhD degree is thus a need for the quality assurance of this degree. In this work, subject-specific and generic competences for the PhD in Food Science and Technology and their alignment with the European Qualifications Framework (EQF level descriptors for quality assurance purposes have been identified.

  15. 基于势概率假设密度滤波的检测前跟踪新算法%Track-Before-Detect algorithm based on cardinalized probability hypothesis density filter

    Institute of Scientific and Technical Information of China (English)

    林再平; 周一宇; 安玮

    2013-01-01

    基于势概率假设密度滤波(Cardinalized Probability Hypothesis Density,CPHD)检测前跟踪(Track before detect,TBD)算法能有效解决未知目标数的弱小目标检测跟踪.文章深入研究了CPHD算法,从标准CPHD滤波的粒子权重更新出发,结合检测前跟踪的实际,合理地推导出CPHD-TBD算法的粒子权重更新表达式;分析了CPHD滤波目标势分布的物理意义,实现了目标势分布更新计算在检测前跟踪的应用.将CPHD滤波和TBD进行有效结合,提出了基于势概率假设密度滤波的检测前跟踪算法,并给出其详细实现步骤.仿真实验证明提出的CPHD-TBD算法与现有概率假设密度检测前跟踪(PHD-TBD)算法相比,能更详细地传递目标分布信息,从本质上改变了PHD-TBD对目标数估计的方式,能更准确稳定估计目标数,实现了对目标的发现和状态准确估计,性能明显更优.

  16. Filter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  17. Pursuit of the Ph.D.

    Directory of Open Access Journals (Sweden)

    Scott P. Kerlin

    1995-11-01

    Full Text Available he thesis is put forward that changes in public policy which originally promoted broad access to higher education are leading to the diminished likelihood that minorities, those from low-income backgrounds and females in underrepresented disciplines will pursue, or be able to complete, the doctorate. By reviewing a wide range of research literature and statistical reports on the status of doctoral education in the U.S. & Canada, a detailed sociological portrait of those who pursue the Ph.D. is presented. Recommendations are given for further research on doctoral education, particularly in areas of attrition,retention, student indebtedness, social stratification, and post-doctoral career plans.

  18. New Synthesis Route for PHD Polyols

    OpenAIRE

    Peshkov, Vladimir; Evtimova, Rozeta; Herzog, Michael; Behrendt, Gerhard

    2011-01-01

    The synthesis of polyurea dispersion polyols (PHD) was developed using a new route via depolymerization of polyurethane polyureas by a mixture of at least two glycols in the presence of a consumable catalyst, i. e. a secondary aliphatic amine. On this way such polyols were produced with a particle size distribution with a maximum in the 120 to 400 nanometer region with hydroxyl numbers of 180 to 300 mg KOH/g being optically clear and highly reactive. The exact adjustment of the ethylene oxide...

  19. Understanding Non-Traditional PhD Students Habitus--Implications for PhD Programmes

    Science.gov (United States)

    Naidoo, Devika

    2015-01-01

    Against the background of vast changes in doctoral education and the emergence of non-traditional doctoral programmes, this paper investigates the habitus of non-traditional PhD students at a South African university. Bourdieu's conceptual tool of habitus informed the study. In-depth and open-ended interviews were conducted with 10 non-traditional…

  20. Molecular Cloning of phd1 and Comparative Analysis of phd1, 2, and 3 Expression in Xenopus laevis

    Directory of Open Access Journals (Sweden)

    Dandan Han

    2012-01-01

    Full Text Available Intensive gene targeting studies in mice have revealed that prolyl hydroxylase domain proteins (PHDs play important roles in murine embryonic development; however, the expression patterns and function of these genes during embryogenesis of other vertebrates remain largely unknown. Here we report the molecular cloning of phd1 and systematic analysis of phd1, phd2, and phd3 expression in embryos as well as adult tissues of Xenopus laevis. All three phds are maternally provided during Xenopus early development. The spatial expression patterns of phds genes in Xenopus embryos appear to define a distinct synexpression group. Frog phd2 and phd3 showed complementary expression in adult tissues with phd2 transcription levels being high in the eye, brain, and intestine, but low in the liver, pancreas, and kidney. On the contrary, expression levels of phd3 are high in the liver, pancreas, and kidney, but low in the eye, brain, and intestine. All three phds are highly expressed in testes, ovary, gall bladder, and spleen. Among three phds, phd3 showed strongest expression in heart.

  1. Filters in topology optimization

    DEFF Research Database (Denmark)

    Bourdin, Blaise

    1999-01-01

    In this article, a modified (``filtered'') version of the minimum compliance topology optimization problem is studied. The direct dependence of the material properties on its pointwise density is replaced by a regularization of the density field using a convolution operator. In this setting...... it is possible to establish the existence of solutions. Moreover, convergence of an approximation by means of finite elements can be obtained. This is illustrated through some numerical experiments. The ``filtering'' technique is also shown to cope with two important numerical problems in topology optimization...

  2. Filters in topology optimization

    DEFF Research Database (Denmark)

    Bourdin, Blaise

    1999-01-01

    In this article, a modified (``filtered'') version of the minimum compliance topology optimization problem is studied. The direct dependence of the material properties on its pointwise density is replaced by a regularization of the density field using a convolution operator. In this setting...... it is possible to establish the existence of solutions. Moreover, convergence of an approximation by means of finite elements can be obtained. This is illustrated through some numerical experiments. The ``filtering'' technique is also shown to cope with two important numerical problems in topology optimization...

  3. Optimal filtering

    CERN Document Server

    Anderson, Brian D O

    2005-01-01

    This graduate-level text augments and extends beyond undergraduate studies of signal processing, particularly in regard to communication systems and digital filtering theory. Vital for students in the fields of control and communications, its contents are also relevant to students in such diverse areas as statistics, economics, bioengineering, and operations research.Topics include filtering, linear systems, and estimation; the discrete-time Kalman filter; time-invariant filters; properties of Kalman filters; computational aspects; and smoothing of discrete-time signals. Additional subjects e

  4. Research Collaboration and Commercialization: The PhD Candidate Perspective

    Science.gov (United States)

    Dooley, Lawrence; Kenny, Breda

    2015-01-01

    This paper explores PhD students' perceptions of their entrepreneurial and commercial capabilities, their attitude towards university supports and the extent to which they engage in external collaboration. The study concentrated on current PhD researchers at one university in Ireland as a unit of analysis and provides encouraging evidence from the…

  5. Tracking the PhD Students' Daily Computer Use

    Science.gov (United States)

    Sim, Kwong Nui; van der Meer, Jacques

    2015-01-01

    This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

  6. The Importance of Having a Ph.D., Career Advice

    Science.gov (United States)

    A presentation on the importance of having a PhD to motivate Initiative to Maximize Student Diversity Program (IMSD) undergrads towards conducting research, pursuing careers in the biomedical field, applying to grad school, and getting a Ph.D., based upon ARS scientist's experiences as a student, a ...

  7. Biomedical PhD education - an international perspective

    DEFF Research Database (Denmark)

    Mulvany, Michael J.

    2013-01-01

    tenured university positions. However, over the past 20–30 years, and particularly the past 10 years, the situation has changed dramatically. Governments in many countries have invested massively in PhD education, believing that trained researchers will contribute to the ‘knowledge society’, and thus...... increase the competitiveness of their countries in the future economies of the world. Thus, only a small fraction of PhD graduates now end up in academic research. Yet, the PhD remains a research degree, and indeed, institutions have become heavily dependent on PhD students for their research output...... during their PhD studies. The purpose of this article is to explore how this seeming paradox is being addressed in biomedicine and to show that far from being inconsistent that the two aspects are in fact complementary. The article is based on the author’s experience as Head of Aarhus Graduate School...

  8. ['Sandwich PhD': considerations for a successful experience abroad].

    Science.gov (United States)

    Salvetti, Marina de Goes; Bueno, Mariana; Gastaldo, Denise; Kimura, Amélia Fumiko; Pimenta, Cibele Andrucioli de Mattos

    2013-03-01

    International PhD internship, named "Sandwich PhD" in Brazil is an opportunity to improve research abilities, to become known in academic area and to establish and/or increase work opportunities in an international context. In this article, we describe key factors regarding the planning and development of the "Sandwich PhD" as experienced by professors and students involved in the collaboration between the School of Nursing, University of São Paulo and Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Canada. We also present the participation of PhD students' network as an alternative to the "Sandwich PhD". An international experience, when well-planned and developed correctly, promotes students' personal and professional development and favors the internationalization of Brazilian graduate programs and research groups.

  9. Launching a Geoscience Career: Insights Gained from MS PHD'S Beyond the PhD

    Science.gov (United States)

    Guzman, W. I.; Johnson, A.; Williamson Whitney, V.; Jansma, P. E.; Huggans, M. J.; Ricciardi, L.

    2013-05-01

    The Beyond the PhD (B-PhD) Professional Development Program is the newest addition to the Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S®) Professional Development Program in Earth System Science. This exciting new program is designed to facilitate the development of a new community of underrepresented minority (URM) doctoral candidates and recent doctorate degree recipients in Earth system science (ESS)-related fields. Building upon MS PHD'S extensive professional development activities provided to URM undergraduate and graduate students, B-PhD's vision is to encourage and support URM doctoral students and early career PhD's in becoming part of the global workforce. (Since its inception in 2003, MSPHD'S supports 213 participants of which 42 have achieved the doctoral degree and another 71 are enrolled in doctoral programs.) By providing customized support and advocacy for participants, B-PhD facilitates smoother and informed transitions from graduate school to postdoctoral and tenure-track positions, as well as other "first" jobs in academia, government, industry, and non-profit organizations. In 2011, the first conference for 18 doctoral candidate and recent graduates was hosted at the University of Texas at Arlington's (UTA) College of Science. Using a format of guest speakers, brown bag discussions, and interactive breakout sessions, participants engaged in sessions entitled "Toolkits for Success in Academia, Business and Industry, Federal Government and Non-Profits", "Defining Short, Mid and Long Term Career Goals", "Accessing and Refining Skill Sets and Other Door Openers", "International Preparation and Opportunities", "Paying it Forward/Lifting as You Climb", and "Customized Strategies for Next Steps". This presentation will discuss outcomes from this pilot project, the use of social media to track and support ongoing B-PhD activities, and objectives for future B-PhD workshops.

  10. Italia-Netherland PhD Program: the I.O. PhD Research Program.

    Science.gov (United States)

    Bellissima, Valentina; Borghesi, Alessandro; Bozzetti, Valentina; Dessì, Angelica; Fabiano, Adele; Risso, Francesco M; Salvo, Vincenzo; Satriano, Angela; Silvagni, Davide; Varrica, Alessandro; van Bel, Frank; Visser, Gerard H A; Vles, Hans Js; Zimmermann, Luc J I; Gavilanes, Antonio D W; Gazzolo, Diego

    2011-10-01

    In the framework of long-term scientific collaboration among the founder members coming from Holland and Italy there was a growing consensus to activate a philosophical doctorate (PhD) program, involving young Italian researchers in the field of perinatal medicine, neonatology and pediatrics. The aims were to promote excellence in research, offering to young Italian physicians the opportunity to maturate an International research experience leading to PhD degree, and to promote human and technological improvement energies in perinatal, neonatal and pediatrics research. Thus, an official collaboration among the Dutch Universities from Maastricht and Utrecht and the Italian Children's Hospital from Alessandria, has been activated on March 1st 2010, finalized to the PhD program. The experimental phase included the selection of projects and relative candidates after an interview-selection focusing on their scientific attitudes and the availability on their research projects. Candidates' selection started on May 2010 and on September 29th ten projects and candidates have been approved by the scientific commission. Research topics included: perinatal asphyxia, aging and the origin of adulthood neurodegenerative disease, neuroprotective strategies, biochemical pulmonology, intrauterine growth retardation and perinatal teratology. To date, all projects have been approved by local Ethics Committee from the University/Hospital of origin of the candidates. Five manuscripts have been published and/or submitted to international Journals regarding pneumology, perinatal asphyxia and teratology, whilst about 60-70% of data regarding clinical studies have already been collected.

  11. Particle filter based entropy

    NARCIS (Netherlands)

    Boers, Y.; Driessen, Hans; Bagchi, Arunabha; Mandal, Pranab K.

    For many problems in the field of tracking or even the wider area of filtering the a posteriori description of the uncertainty can oftentimes not be described by a simple Gaussian density function. In such situations the characterization of the uncertainty by a mean and a covariance does not capture

  12. Ultraviolet filters.

    Science.gov (United States)

    Shaath, Nadim A

    2010-04-01

    The chemistry, photostability and mechanism of action of ultraviolet filters are reviewed. The worldwide regulatory status of the 55 approved ultraviolet filters and their optical properties are documented. The photostabilty of butyl methoxydibenzoyl methane (avobenzone) is considered and methods to stabilize it in cosmetic formulations are presented.

  13. 2. mednarodna konferenca My PhD = 2nd My phd International Conference

    Directory of Open Access Journals (Sweden)

    Armand Faganel

    2008-09-01

    Full Text Available The article presents the organization of the second My phd InternationalConference organized in June in Bratislava. The organizer Friedrich Ebert Foundation is a German non-profit organization. During the conference young researchers from various fields dealt with the issue of ‘New Europe’ and the challenges of sustainable development. The conference was also an opportunity for young researchers to meet new colleagues and exchange their views. The interest was very big since only 40 percent of the applicants were accepted. Another interesting thing was the competitive approach towards the conference, which means that only the best articles will be published in the conference proceedings.

  14. Short Hairpin RNA Silencing of PHD-2 Improves Neovascularization and Functional Outcomes in Diabetic Wounds and Ischemic Limbs.

    Directory of Open Access Journals (Sweden)

    Kevin J Paik

    Full Text Available The transcription factor hypoxia-inducible factor 1-alpha (HIF-1α is responsible for the downstream expression of over 60 genes that regulate cell survival and metabolism in hypoxic conditions as well as those that enhance angiogenesis to alleviate hypoxia. However, under normoxic conditions, HIF-1α is hydroxylated by prolyl hydroxylase 2, and subsequently degraded, with a biological half-life of less than five minutes. Here we investigated the therapeutic potential of inhibiting HIF-1α degradation through short hairpin RNA silencing of PHD-2 in the setting of diabetic wounds and limb ischemia. Treatment of diabetic mouse fibroblasts with shPHD-2 in vitro resulted in decreased levels of PHD-2 transcript demonstrated by qRT-PCR, higher levels of HIF-1α as measured by western blot, and higher expression of the downstream angiogenic genes SDF-1 and VEGFα, as measured by qRT-PCR. In vivo, shPHD-2 accelerated healing of full thickness excisional wounds in diabetic mice compared to shScr control, (14.33 ± 0.45 days vs. 19 ± 0.33 days and was associated with an increased vascular density. Delivery of shPHD-2 also resulted in improved perfusion of ischemic hind limbs compared to shScr, prevention of distal digit tip necrosis, and increased survival of muscle tissue. Knockdown of PHD-2 through shRNA treatment has the potential to stimulate angiogenesis through overexpression of HIF-1α and upregulation of pro-angiogenic genes downstream of HIF-1α, and may represent a viable, non-viral approach to gene therapy for ischemia related applications.

  15. Brenda K. Edwards, PhD | DCCPS/NCI/NIH

    Science.gov (United States)

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  16. Meet EPA Scientist Michael Nye, Ph.D.

    Science.gov (United States)

    Michael Nye, Ph.D., is a social scientist who studies natural risk, socio-demographic change and sustainable behavior. Prior to joining EPA, he worked for the UK Environment Agency in flood risk management and emergency preparedness

  17. ebibliographical compilation of phd theses produced at the faculty of ...

    African Journals Online (AJOL)

    USER

    2015-06-01

    Jun 1, 2015 ... This paper attempts to provide a systematic list of Ph.D theses produced by the. Faculty of Science ... field of library and information science the concept of bibliography .... Information System (GIS) in Kano State,. Nigeria.

  18. Meet EPA Engineer Shawn Ryan, Ph.D.

    Science.gov (United States)

    Shawn Ryan, Ph.D. is a chemical engineer at EPA's National Homeland Security Research Center. He has worked at EPA for 12 years, nine of which have been devoted to leading research to support decontamination and consequence management.

  19. Meet EPA Scientist Tim Shafer, Ph.D.

    Science.gov (United States)

    Tim Shafer earned his bachelor’s degree in biology and chemistry from Hope College in Holland, MI, in 1986 and his Ph.D. in pharmacology and environmental toxicology from Michigan State University in 1991.

  20. Meet EPA Scientist Susan Yee, Ph.D.

    Science.gov (United States)

    Susan Yee, Ph.D., is an ecologist at EPA's Gulf Ecology Division. She is working on the Puerto Rico Sustainable Communities program, developing decision support tools to evaluate how alternative decisions impact coastal ecosystem goods and services

  1. Meet EPA Chemist Quincy Teng, Ph.D.

    Science.gov (United States)

    EPA research chemist Quincy Teng, Ph.D., focuses on the application of metabolomics—a relatively new, specialized field of biochemistry focused on studying small molecules known as metabolites—on environmental and life sciences.

  2. Structural insight into histone recognition by the ING PHD fingers.

    Science.gov (United States)

    Champagne, Karen S; Kutateladze, Tatiana G

    2009-05-01

    The Inhibitor of Growth (ING) tumor suppressors are implicated in oncogenesis, control of DNA damage repair, cellular senescence and apoptosis. All members of the ING family contain unique amino-terminal regions and a carboxy-terminal plant homeodomain (PHD) finger. While the amino-terminal domains associate with a number of protein effectors including distinct components of histone deacetylase (HDAC) and histone acetyltransferase (HAT) complexes, the PHD finger binds strongly and specifically to histone H3 trimethylated at lysine 4 (H3K4me3). In this review we describe the molecular mechanism of H3K4me3 recognition by the ING1-5 PHD fingers, analyze the determinants of the histone specificity and compare the biological activities and structures within subsets of PHD fingers. The atomic-resolution structures of the ING PHD fingers in complex with a H3K4me3 peptide reveal that the histone tail is bound in a large and deep binding site encompassing nearly one-third of the protein surface. An extensive network of intermolecular hydrogen bonds, hydrophobic and cation-pi contacts, and complementary surface interactions coordinate the first six residues of the H3K4me3 peptide. The trimethylated Lys4 occupies an elongated groove, formed by the highly conserved aromatic and hydrophobic residues of the PHD finger, whereas the adjacent groove accommodates Arg2. The two grooves are connected by a narrow channel, the small size of which defines the PHD finger's specificity, excluding interactions with other modified histone peptides. Binding of the ING PHD fingers to H3K4me3 plays a critical role in regulating chromatin acetylation. The ING proteins function as tethering molecules that physically link the HDAC and HAT enzymatic complexes to chromatin. In this review we also highlight progress recently made in understanding the molecular basis underlying biological and tumorigenic activities of the ING tumor suppressors.

  3. In situ microbial filter used for bioremediation

    Science.gov (United States)

    Carman, M. Leslie; Taylor, Robert T.

    2000-01-01

    An improved method for in situ microbial filter bioremediation having increasingly operational longevity of an in situ microbial filter emplaced into an aquifer. A method for generating a microbial filter of sufficient catalytic density and thickness, which has increased replenishment interval, improved bacteria attachment and detachment characteristics and the endogenous stability under in situ conditions. A system for in situ field water remediation.

  4. Food Filter

    Institute of Scientific and Technical Information of China (English)

    履之

    1995-01-01

    A typical food-processing plant produces about 500,000 gallons of waste water daily. Laden with organic compounds, this water usually is evaporated or discharged into sewers.A better solution is to filter the water through

  5. The Production Rate and Employment of Ph.D. Astronomers

    CERN Document Server

    Metcalfe, Travis S

    2007-01-01

    In an effort to promote self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astr...

  6. The Production Rate and Employment of Ph.D. Astronomers

    Science.gov (United States)

    Metcalfe, Travis S.

    2008-02-01

    In an effort to encourage self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astronomy and astrophysics. The average new astronomer might expect to hold up to 3 jobs before finding a steady position.

  7. Recycling used automotive oil filters

    Science.gov (United States)

    Peaslee, Kent D.

    1994-02-01

    Over 400 million used automotive oil filters are discarded in the United States each year, most of which are disposed of in landfills wasting valuable resources and risking contamination of ground- and surface-water supplies. This article summarizes U.S. bureau of Mines research evaluating scrap prepared from used automotive oil filters. Experimental results show that crushed and drained oil filters have a bulk density that is higher than many typical scrap grades, a chemical analysis low in residual elements (except tin due to use of tin plate in filters), and an overall yield, oil-filter scrap to cast steel, of 76% to 85%, depending on the method used to prepare the scrap.

  8. Tesi di dottorato PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2000-06-01

    Full Text Available

    Segnalazione di tesi di dottorato.

     

    Miguel Calleja Puerta

    El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000

     

    Adele Cilento

    Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000

     

    Amedeo De Vincentiis

    Firenze e i signori. Sperimentazioni istituzionali e modelli di regime nelle signorie fiorentine degli Angioini (fine XIII - metà XIV secolo, Tesi di dottorato di ricerca in Storia medioevale (XI ciclo, Università degli Studi di Milano, 1999

     

    Marco Folin

    Il sistema politico di un antico Stato italiano: i ducati estensi nella prima Età moderna (1452-1598, Tesi di dottorato di ricerca in Storia, Scuola Normale superiore di Pisa, 2000

     

    Barbara Frale

    Guardiani del Santuario. Le radici orientali del processo contro l’ordine del Tempio (1128 - 1314, Tesi di dottorato di ricerca in Storia sociale d’Europa (XI ciclo, Università "Ca’ Foscari" di Venezia, 2000

    Report of PhD Dissertations.

     

    Miguel Calleja Puerta

    El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000

     

    Adele Cilento

    Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000

     

    Amedeo De Vincentiis

    Firenze e

  9. Notch filter

    Science.gov (United States)

    Shelton, G. B. (Inventor)

    1977-01-01

    A notch filter for the selective attenuation of a narrow band of frequencies out of a larger band was developed. A helical resonator is connected to an input circuit and an output circuit through discrete and equal capacitors, and a resistor is connected between the input and the output circuits.

  10. Dido3 PHD Modulates Cell Differentiation and Division

    Directory of Open Access Journals (Sweden)

    Jovylyn Gatchalian

    2013-07-01

    Full Text Available Death Inducer Obliterator 3 (Dido3 is implicated in the maintenance of stem cell genomic stability and tumorigenesis. Here, we show that Dido3 regulates the expression of stemness genes in embryonic stem cells through its plant homeodomain (PHD finger. Binding of Dido3 PHD to histone H3K4me3 is disrupted by threonine phosphorylation that triggers Dido3 translocation from chromatin to the mitotic spindle. The crystal structure of Dido3 PHD in complex with H3K4me3 reveals an atypical aromatic-cage-like binding site that contains a histidine residue. Biochemical, structural, and mutational analyses of the binding mechanism identified the determinants of specificity and affinity and explained the inability of homologous PHF3 to bind H3K4me3. Together, our findings reveal a link between the transcriptional control in embryonic development and regulation of cell division.

  11. An analysis of Ph.D. examiners' reports in engineering

    Science.gov (United States)

    Prieto, Elena; Holbrook, Allyson; Bourke, Sid

    2016-03-01

    In recent years, there have been increasing calls for an overall transformation of the nature of engineering Ph.D. programs and the way theses are assessed. There exists a need to understand the examination process to ensure the best quality outcome for candidates in engineering. The work we present in this paper uses data collected between 2003 and 2010 for a total of 1220 Australian Ph.D. theses by analysing examiner reports. Our analysis indicates that Ph.D. theses in engineering, N = 106, differ considerably from those in other fields in areas such as gender of candidates and examiners and the examiners' geographical location. We also found that assessment areas such as significance and contribution of the thesis, publications arising from the thesis, breadth, depth and recency of the literature review and communication and editorial correctness are areas in which the proportion of text of engineering examiners' comments differs significantly from other fields.

  12. Mid-Career PhD Physicists: Academia & Beyond

    Science.gov (United States)

    White, Susan

    2017-01-01

    What jobs do mid-career PhD physicists hold? In a first-ever study, we collected data in 2011 from over 1,500 physics PhD recipients from the classes of 1996, 1997, 2000, and 2001. About 45% of the physics PhD recipients in these classes immediately took jobs that were not temporary, and over 40% accepted postdocs. How does taking a postdoc affect mid-career employment? What is the relationship between first job (after any postdocs) and mid-career employment? How do physicists' actual jobs compare with what they thought they would be doing when they graduated? Using our initial employment and mid-career data, I will answer these questions and more.

  13. Enhancing the skills of PhD supervisors facing internationalization

    DEFF Research Database (Denmark)

    Bøgelund, Pia

    2013-01-01

    This research started out due to some institutional changes at a department at Aalborg University as regards supervision of PhD students. For various reasons the department suddenly got a large intake of PhD students in 2008, many of which came with an international background. After a period...... of time staff members of the department began to look very frustrated. Not only did they feel burdened with the large intake, they also struggled with the task of facilitating the transition of international students to become independent scholars. The situation led to the creation of a more general...... interview study within the faculty, and an inquiry into the field of cross-cultural supervision with the purpose of enhancing the skills of PhD supervisors. As is often the case with cross-cultural exchange and inquiry, the study ended up by being just as informative on the supervision cultures and settings...

  14. Liquid Permeability of Ceramic Foam Filters

    OpenAIRE

    Zhang, Kexu

    2012-01-01

    This project is in support of the PhD project: ‘Removal of Inclusions from Liquid Aluminium using Electromagnetically Modified Filtration’. The purpose of this project was to measure the tortuosity, and permeability of ~50mm thick: 30, 40, 50 and 80 pores per inch (ppi) commercial alumina ceramic foam filters (CFFs). Measurements have been taken of: cell (pore), window and strut sizes, porosity, tortuosity and liquid permeability. Water velocity from ~0.015-0.77 m/s have been used ...

  15. Probability Density Analysis of SINR in Massive MIMO Downlink Using Matched Filter Beamformer%基于MF预编码的大规模MIMO网络SINR概率密度分析

    Institute of Scientific and Technical Information of China (English)

    束锋; 李隽; 顾晨; 王进; 周叶; 徐彦青; 钱玉文

    2015-01-01

    大规模M IM O系统中,相对于其他基于信道矩阵分解的波束成形算法,如迫零、最小均方误差算法等,匹配滤波(Matched filter ,MF)具有复杂度极低的优点,从而成为一种极具实用潜力的波束成形算法。鉴于此,本文推导了基站采用M F波束成形算法时,用户端信干噪比(Signal‐to‐interference‐and‐noise ratio ,SINR)的近似概率密度函数(Probability density function ,PDF)。该函数对于推导与分析系统性能,如和速率、中断概率等至关重要。仿真表明:当基站天线数趋于大规模时,SINR公式的PDF曲线趋近于通过纯仿真得到的PDF曲线。%In massive MIMO systems ,the matched filter (MF) beamformer is an attractive technique due to its extremely low complexity compared with the high‐complexity decomposition‐based beamforming techniques ,such as zero forcing and minimum mean square error .An approximate formula is derived for probability density function (PDF) of the signal‐to‐interference‐and‐noise ratio (SINR) at user terminal when multiple antennas and the MF beamformer are used at the base station .The formula is important in calculating or analyzing system performance such as sum‐rate and outage probability .Simulations exhibit that the difference between the derived approximate formula for PDF and the simulated PDF approaches zero while the number of antennas at the base station tends to large‐scale .

  16. PhD Dissertations Tesi di dottorato

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-06-01

    Full Text Available

    Report of PhD Dissertations.

    Francesco Barone

    Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004

     

    Laura Berti Ceroni

    Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.

     

    Marco Bicchierai

    Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004

     

    Emanuela Garimberti

    Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004

     

    Lorenzo Tanzini

    Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004

     

    Stefania Tarquini

    Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

    Segnalazione di tesi di dottorato.

    Francesco Barone

    Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004

     

    Laura Berti Ceroni

  17. PhD Dissertations Tesi di dottorato

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-12-01

    Full Text Available

    Report of PhD Dissertations.

    Massimo Della Misericordia

    Divenire comunità. Comuni rurali, poteri signorili, identità sociali in Valtellina e nella montagna lombarda nel tardo medioevo, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Torino, 2003

     

    Mariano Dell’Omo

    Il monastero di S. Liberatore alla Maiella centro dell’irradiazione di Montecassino nell’Abruzzo medievale e moderno. Contributo alla storia dell’organizzazione patrimoniale e della civiltà monastica cassinese nell’Italia centrale attraverso i documenti di S. Liberatore conservati nell’Archivio di Montecassino. Introduzione storica, paleografica e archivistica. Edizione dei documenti più antichi (†798-1000 e regesti di quelli posteriori (1005-1735, Tesi di dottorato in Storia Ecclesiastica, Facoltà di Storia Ecclesiastica, Pontificia Università Gregoriana di Roma,  2004

     

    Giulia Lorenzoni

    Conquistare e governare la città. Forme di potere e istituzioni nel primo anno della signoria viscontea a Bologna (ottobre 1350-novembre 1351, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Bologna, 2004

     

    Federica Monteleone

    Il viaggio di Carlo Magno in Terra Santa. Un’esperienza di pellegrinaggio nella tradizione europea occidentale, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo

     

    Francesca Pucci Donati

    Fra teorie mediche e pratica quotidiana: i calendari dietetici dell’Occidente latino altomedievale (secoli IX-XI, Tesi di dottorato di ricerca in Storia medievale (XV ciclo, Università degli studi di Bologna, 2004

    Alberto Ricciardi

    L’Epistolario di Lupo

  18. PhD Dissertations Tesi di dottorato

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2002-06-01

    Full Text Available

    Report of PhD dissertation.

    Laura Baietto

    Una politica per le città. Rapporti fra papato, vescovi e comuni nell'Italia centro-settentrionale da Innocenzo III a Gregorio IX, Tesi di dottorato di ricerca in Storia Medievale, Università degli Studi di Torino, 2002

     

    Giuseppe Banfo

    Compresenze e sovrapposizioni di poteri territoriali di qualità diversa tra X e XIII: il caso del basso Monferrato, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2002

     

    Francesca Dell'Acqua

    La vetrata tra l'età tardo imperiale e l'altomedioevo: le fonti, l'archeologia, Tesi di Perfezionamento in Storia dell'Arte Medievale, Scuola Normale Superiore di Pisa, 2001

     

    Primo Giovanni Embriaco

    I vescovi di Albenga e gli sviluppi signorili nella Liguria occidentale (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2001

     

    Antonella Ghignoli

    Documenti e proprietà altomedievali. Fondamenti e problemi dell'esegesi storica delle fonti documentarie nello specchio della tradizione delle carte pisane dei secoli VIII-XI, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002

     

    Vito Loré

    Espansione monastica e mutamenti politici. La Trinità di Cava nei suoi rapporti con i sovrani longobardi e normanni e con l'aristocrazia territoriale. Secoli XI-XII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002

     

    Rosaria Stracuzzi

    Messina nel '400, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Palermo, 2001

     

    Stefania Tamburini

  19. Topology optimization of microwave waveguide filters

    CERN Document Server

    Aage, Niels

    2016-01-01

    We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap optimization for the desired filter characteristics. This is illustrated through numerical experiments and comparison to a standard band pass filter design. It is seen that the carefully optimized topologies can sharpen the filter characteristics and improve performance. Furthermore, the obtained designs share little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering.

  20. First International Student Obtains His PhD at CAS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Mr. Ghulam Rasul, the first international student formally enrolled by the Graduate University of CAS (GUCAS) has received his PhD degree this summer after having passed his dissertation defense on May 21 at the CAS Institute of Atmospheric Physics (IAP).

  1. Supervising the PhD: A Guide to Success.

    Science.gov (United States)

    Delamont, Sara; Atkinson, Paul; Parry, Odette

    This handbook is a practical guide for the novice and experienced supervisor of Ph.D. students focusing on the British system. The book is organized to follow the progress of a student from starting out to a career after the viva voce examination. The chapters are: (1) "A Most Persuasive Piece of Argument"; (2) "Caught and Held by a…

  2. Peer Mentorship and Transformational Learning: PhD Student Experiences

    Science.gov (United States)

    Preston, Jane P.; Ogenchuk, Marcella J.; Nsiah, Joseph K.

    2014-01-01

    The purpose of the paper is to describe our peer mentorship experiences and explain how these experiences fostered transformational learning during our PhD graduate program in educational administration. As a literature backdrop, we discuss characteristics of traditional forms of mentorship and depict how our experiences of peer mentorship was…

  3. Richard Mazurchuk, PhD | Division of Cancer Prevention

    Science.gov (United States)

    Dr. Richard Mazurchuk received a BS in Physics and MS and PhD in Biophysics from SUNY Buffalo. His research focused on developing novel multi-modality imaging techniques, contrast (enhancing) agents and methods to assess the efficacy of experimental therapeutics. |

  4. Theo Thole as a PhD ''student''

    NARCIS (Netherlands)

    vanDuijnen, PT

    1997-01-01

    Thee Thole's Ph.D. work was the basis for the Direct Reaction Field method for incorporating a semi-classical ''solvent'' in quantum chemical calculations. The early stages of his work and later progress is reviewed and a typical example of his analytical and programming skills, so far unpublished,

  5. How Broad Liberal Arts Training Produces Phd Economists: Carleton's Story

    Science.gov (United States)

    Bourne, Jenny; Grawe, Nathan D.

    2015-01-01

    Several recent studies point to strong performance in economics PhD programs of graduates from liberal arts colleges. While every undergraduate program is unique and the likelihood of selection bias combines with small sample sizes to caution against drawing strong conclusions, the authors reflect on their experience at Carleton College to…

  6. PhD by Publication: A Student's Perspective

    Directory of Open Access Journals (Sweden)

    Peter Kanowski

    2008-01-01

    Full Text Available This article presents the first author's experiences as an Australian doctoral student undertaking a PhD by publication in the arena of the social sciences. She published nine articles in refereed journals and a peer-reviewed book chapter during the course of her PhD. We situate this experience in the context of current discussion about doctoral publication practices, in order to inform both postgraduate students and academics in general. The article discusses recent thinking about PhD by publication and identifies the factors that students should consider prior to adopting this approach, in terms of university requirements, supervisors' attitudes, the research subject matter, intellectual property, capacity and working style, and issues of co-authorship. It then outlines our perceptions of the advantages and disadvantages of undertaking a PhD by publication. We suggest that, in general, the advantages outweigh the disadvantages. We conclude by reflecting on how the first author's experiences relate to current discussions about fostering publications by doctoral students.

  7. Ph.d. report nº1

    DEFF Research Database (Denmark)

    Hernandez, Lorenzo Banos

    The following report serves as an introduction to the Ph.d subject "Control system Modeling of the Wave Star Energy's Power Take-O". The device studied belongs to the Wave Energy field, which forms part of the renewable hydro Power generation sector. In Denmark, following the succesful course...

  8. Proceedings of the ICTSS 2012 PhD Workshop - Preface

    DEFF Research Database (Denmark)

    Nielsen, Brian; Weise, Carsten

    2012-01-01

    , theoretic, and practical challenges of testing software systems, including communication protocols, services, distributed platforms, middleware, embedded systems, and security infrastructures. The aims of the ICTSS Doctoral Workshop is to provide a forum for PhD students to present preliminary results...

  9. PhD thesis: The relationship between expertise and creativity

    DEFF Research Database (Denmark)

    Boysen, Mikkel Snorre Wilms

    2015-01-01

    I Ph.d. projektet undersøges sammenhænge mellem ekspertise og kreativitet via et eksperiment, hvor eksperter og novicer laver musik ved computer. Musikken vurderes efterfølgende af en række fokusgrupper. Studiet peger overraskende på, at novicer på linje med eksperter er i stand til at skabe musi...

  10. Ph.D Afhandling: Restaurering verus instaurering og transstaurering

    DEFF Research Database (Denmark)

    Bech-Nielsen, Grith

    2012-01-01

    Ph.d. afhandlingen udforsker holdningen som arkitektfagligt instrument. Fagudøverens "holdning" til værdisætning af arkitektoniske kulturarvsobjekter og til arkitektonisk intervention heri fungerer aktuelt som et anerkendt og konstituerende beslutningsinstrument i praksisnære processer og sammenh...

  11. PhD Dissertations Tesi di dottorato

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-12-01

    Full Text Available Report of PhD Dissertations.Anna Airò La scrittura delle regole. Politica e istituzioni a Taranto nel Quattrocento, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Pasquale Arfé La Clavis Physicae II (316-529 di Honorius Augustodunensis. Studio ed edizione critica, Tesi di dottorato in Storia della filosofia medievale, Università degli Studi di Napoli "L'Orientale", 2005 Alessandro Azzimonti Scrittura agiografica e strutture di potere nell'Italia centro-settentrionale (X-XII secolo, Tesi di dottorato di ricerca in Forme del sapere storico dal medioevo alla contemporaneità, Università degli Studi di Trieste, 2004 Domenico Cerami Il "Confine conteso". Uomini, istituzioni, culture a Monteveglio tra VIII-XII secolo, Tesi di dottorato di ricerca in Storia Medievale, Università degli studi di Bologna, 2005 Federica Chilà Ostaggi. Uno strumento di pacificazione e governo tra i secoli VIII e XII, Tesi di dottorato di ricerca in Istituzioni, società, religioni dal Tardo Antico alla fine del Medioevo, Università degli Studi di Torino, 2004 Enrico Faini Firenze nei secoli X-XIII: economia e società, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005Alessio FioreStrutture e pratiche del potere signorile in area umbro-marchigiana (secoli XI-XIII, Tesi di dottorato ricerca in Storia, Università degli studi di Pisa, 2004Giampaolo FrancesconiTra Riforma, vescovo e clientes. Camaldoli e le società locali (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 [09/05] Giuseppe Gardoni "Episcopus et potestas". Vescovi e società a Mantova nella prima metà del Duecento, Tesi di dottorato di ricerca in Storia del Cristianesimo e delle Chiese (antichità, medioevo, età moderna, Università degli Studi di Padova, 2005 Nicola Mancassola La gestione delle campagne tra Langobardia e Romània in età carolingia e post

  12. CRYSTAL FILTER TEST SET

    Science.gov (United States)

    CRYSTAL FILTERS, *HIGH FREQUENCY, *RADIOFREQUENCY FILTERS, AMPLIFIERS, ELECTRIC POTENTIAL, FREQUENCY, IMPEDANCE MATCHING , INSTRUMENTATION, RADIOFREQUENCY, RADIOFREQUENCY AMPLIFIERS, TEST EQUIPMENT, TEST METHODS

  13. Undertaking Individual Transdisciplinary PhD Research for Sustainable Development: Case Studies from South Africa

    Science.gov (United States)

    van Breda, John; Musango, Josephine; Brent, Alan

    2016-01-01

    Purpose: This paper aims to improve the understanding of individual transdisciplinary PhD research in a developing country context, focusing on three individual PhD case studies in South Africa. Design/Methodology/Approach: Multiple-case method was used, and three completed transdisciplinary PhD research efforts undertaken at the Stellenbosch…

  14. Undertaking Individual Transdisciplinary PhD Research for Sustainable Development: Case Studies from South Africa

    Science.gov (United States)

    van Breda, John; Musango, Josephine; Brent, Alan

    2016-01-01

    Purpose: This paper aims to improve the understanding of individual transdisciplinary PhD research in a developing country context, focusing on three individual PhD case studies in South Africa. Design/Methodology/Approach: Multiple-case method was used, and three completed transdisciplinary PhD research efforts undertaken at the Stellenbosch…

  15. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  16. Sensitivity filtering from a continuum mechanics perspective

    DEFF Research Database (Denmark)

    Sigmund, Ole; Maute, Kurt

    2012-01-01

    In topology optimization filtering is a popular approach for preventing numerical instabilities. This short note shows that the well-known sensitivity filtering technique, that prevents checkerboards and ensures mesh-independent designs in density-based topology optimization, is equivalent to min...... to minimizing compliance for nonlocal elasticity problems known from continuum mechanics. Hence, the note resolves the long-standing quest for finding an explanation and physical motivation for the sensitivity filter....

  17. Granular filters for water treatment: heterogeneity and diagnostic tools

    DEFF Research Database (Denmark)

    Lopato, Laure Rose

    the last barrier against disinfection resistant protozoan pathogens and this has led to increased regulation of the filtration process. To be able to produce high-quality filtrate in a constant and reliable manner while meeting stricter drinking water guideline values, it is important to be able...... to be able to observe the physical state of the filter. The aim of this PhD study is to contribute to the understanding and optimization of the granular media filtration process. The focus of the work is to develop methodologies and diagnostic tools to analyze the physical state of rapid filters and improve....... Similarly, despite the importance of nitrification in groundwater treatment, the removal of ammonium and the determination of the kinetics of nitrification have been insufficiently researched in full-scale filters. A tool is developed to describe nitrification quantitatively on full-scale filters under real...

  18. Interpolation and Iteration for Nonlinear Filters

    CERN Document Server

    Chorin, Alexandre J

    2009-01-01

    We present a general form of the iteration and interpolation process used in implicit particle filters. Implicit filters are based on a pseudo-Gaussian representation of posterior densities, and are designed to focus the particle paths so as to reduce the number of particles needed in nonlinear data assimilation. Examples are given.

  19. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  20. Soybean GmPHD-type transcription regulators improve stress tolerance in transgenic Arabidopsis plants.

    Directory of Open Access Journals (Sweden)

    Wei Wei

    Full Text Available BACKGROUND: Soybean [Glycine max (L. Merr.] is one of the most important crops for oil and protein resource. Improvement of stress tolerance will be beneficial for soybean seed production. PRINCIPAL FINDINGS: Six GmPHD genes encoding Alfin1-type PHD finger protein were identified and their expressions differentially responded to drought, salt, cold and ABA treatments. The six GmPHDs were nuclear proteins and showed ability to bind the cis-element "GTGGAG". The N-terminal domain of GmPHD played a major role in DNA binding. Using a protoplast assay system, we find that GmPHD1 to GmPHD5 had transcriptional suppression activity whereas GmPHD6 did not have. In yeast assay, the GmPHD6 can form homodimer and heterodimer with the other GmPHDs except GmPHD2. The N-terminal plus the variable regions but not the PHD-finger is required for the dimerization. Transgenic Arabidopsis plants overexpressing the GmPHD2 showed salt tolerance when compared with the wild type plants. This tolerance was likely achieved by diminishing the oxidative stress through regulation of downstream genes. SIGNIFICANCE: These results provide important clues for soybean stress tolerance through manipulation of PHD-type transcription regulator.

  1. Club of Bologna International Best PhD Prize 2012

    Directory of Open Access Journals (Sweden)

    Marco Fiala

    2012-06-01

    Full Text Available The Club of Bologna, in collaboration with UNACOMA, will be awarding a prize for the best PhD theses on subjects related to agricultural machinery design and development. Up to ten theses will be selected and the best five of these will have the chance of being presented during the annual Club of Bologna meeting that will be held from 9 to 10 November 2012, on occasion of the EIMA. The authors of the best three PhD theses will also receive a cash prize. The winners will be guests in Bologna of UNACOMA who will cover travelling expenses and hotel accommodation for 2 nights. They will also meet farm machinery manufacturers attending the international trade fair. The winners of the Club of Bologna Prize 2012 will be announced here. Application forms and further information can be downloaded from the Club of Bologna website (http://www.clubofbologna.org/.

  2. Cluster Sampling Filters for Non-Gaussian Data Assimilation

    OpenAIRE

    2016-01-01

    This paper presents a fully non-Gaussian version of the Hamiltonian Monte Carlo (HMC) sampling filter. The Gaussian prior assumption in the original HMC filter is relaxed. Specifically, a clustering step is introduced after the forecast phase of the filter, and the prior density function is estimated by fitting a Gaussian Mixture Model (GMM) to the prior ensemble. Using the data likelihood function, the posterior density is then formulated as a mixture density, and is sampled using a HMC appr...

  3. Numerical Simulation of a Linear Filter.

    Science.gov (United States)

    1967-05-05

    spectral density function . The study determines to what degree this method simulates a linear filter. Also included are correlation analyses of equidistributed sequences which are used in the method. (Author)

  4. Iranian PhD student wins human-rights prize

    Science.gov (United States)

    Cartwright, Jon

    2013-11-01

    A physicist imprisoned in Iran while on a break from his PhD studies in the US has been awarded a human-rights prize. Omid Kokabee, who had been based at the University of Texas in Austin, has been given the Andrei Sakharov Prize from the American Physical Society (APS) for "his courage in refusing to use his physics knowledge to work on projects that he deemed harmful to humanity, in the face of extreme physical and psychological pressure".

  5. Ph.d. om interne sociale medier : Det sociale intranet

    DEFF Research Database (Denmark)

    Madsen, Vibeke Thøis

    2017-01-01

    Det sociale intranet eller interne sociale medier vækker drømme hos virksomheder, som ser en mulighed for at involvere og engagere medarbejderne. Det sociale intranet bliver opfattet som en genvej til mere innovative og effektive virksomheder. En ny ph.d. om medarbejderne som kommunikatører på...... interne sociale medier viser imidlertid, at virksomheder kæmper med at skabe en aktiv og levende kommunikation på det sociale intranet...

  6. Critical issues in PhD training for biomedical scientists.

    Science.gov (United States)

    Juliano, R L; Oxford, G S

    2001-10-01

    The rapidly changing world of modern biomedical research is raising important new issues for traditional PhD training programs and is creating concern among young PhD scientists about their futures. Specifically, the United States is producing substantially more biomedical PhDs than can be accommodated in professional positions that truly require the PhD as a credential. The "surplus" PhD population is being relegated to poorly paid, unstable, and increasingly unsatisfying jobs. In addition, many current graduate and postdoctoral training programs may not be adequately preparing young scientists for the more complex, more quantitative biological science of the future. Finally, many current graduate training programs are not attracting a sufficient portion of the most talented young people in the nation. To ameliorate these problems in the training and early career paths of basic biomedical scientists, the authors make specific recommendations, such as urging (1) that graduate trainees should be supported exclusively by competitive individual fellowships, training grants, or institutional funds and not by RO1s or similar research awards; (2) that graduate and postdoctoral stipends be increased so that they provide a reasonable living wage; and (3) that research-intensive academic institutions create a career path for biomedical PhDs other than that designed for the traditional tenure-track, grant-funded principal investigator and faculty member. They conclude that it is in the interest of faculty and institutions to make these and other drastic changes because the current system is both inherently unfair and self-destructive.

  7. Convergent Filter Bases

    OpenAIRE

    Coghetto Roland

    2015-01-01

    We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres) and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections).

  8. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  9. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    Science.gov (United States)

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  10. Image Filtering Driven by Level Curves

    Science.gov (United States)

    Rajwade, Ajit; Banerjee, Arunava; Rangarajan, Anand

    This paper presents an approach to image filtering that is driven by the properties of the iso-valued level curves of the image and their relationship with one another. We explore the relationship of our algorithm to existing probabilistically driven filtering methods such as those based on kernel density estimation, local-mode finding and mean-shift. Extensive experimental results on filtering gray-scale images, color images, gray-scale video and chromaticity fields are presented. In contrast to existing probabilistic methods, in our approach, the selection of the parameter that prevents diffusion across the edge is robustly decoupled from the smoothing of the density itself. Furthermore, our method is observed to produce better filtering results for the same settings of parameters for the filter window size and the edge definition.

  11. The Cancer Cell Oxygen Sensor PHD2 Promotes Metastasis via Activation of Cancer-Associated Fibroblasts

    Directory of Open Access Journals (Sweden)

    Anna Kuchnio

    2015-08-01

    Full Text Available Several questions about the role of the oxygen sensor prolyl-hydroxylase 2 (PHD2 in cancer have not been addressed. First, the role of PHD2 in metastasis has not been studied in a spontaneous tumor model. Here, we show that global PHD2 haplodeficiency reduced metastasis without affecting tumor growth. Second, it is unknown whether PHD2 regulates cancer by affecting cancer-associated fibroblasts (CAFs. We show that PHD2 haplodeficiency reduced metastasis via two mechanisms: (1 by decreasing CAF activation, matrix production, and contraction by CAFs, an effect that surprisingly relied on PHD2 deletion in cancer cells, but not in CAFs; and (2 by improving tumor vessel normalization. Third, the effect of concomitant PHD2 inhibition in malignant and stromal cells (mimicking PHD2 inhibitor treatment is unknown. We show that global PHD2 haplodeficiency, induced not only before but also after tumor onset, impaired metastasis. These findings warrant investigation of PHD2’s therapeutic potential.

  12. Miniaturized dielectric waveguide filters

    Science.gov (United States)

    Sandhu, Muhammad Y.; Hunter, Ian C.

    2016-10-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  13. Applied PhD Research in a Work-Based Environment: An Activity Theory-Based Analysis

    Science.gov (United States)

    Granata, S. N.; Dochy, F.

    2016-01-01

    Activity theory is used to compare PhD undertaken at university, that is, academic PhD, with PhD performed in collaboration with industry, that is, semi-industrial PhD. The research is divided into a literature review and a case study. Semi-industrial and academic PhD are modelled as activity systems, and differences are highlighted in terms of…

  14. Leonard F. Peltier, MD, PhD, 1920-2003.

    Science.gov (United States)

    Reckling, Frederick W; Lo Vecchio, Janolyn G; Reckling, JoAnn B

    2004-05-01

    Leonard F. Peltier, MD, PhD, was an orthopaedic surgeon, academician, administrator, laboratory investigator, historian, and mentor. His career spanned nearly six decades, beginning with graduate education at the University of Minnesota (UM) under the auspices of Owen H. Wangensteen, MD, PhD. In addition to obtaining a PhD in physiology in the UM Graduate School, he completed general and orthopaedic surgery residencies and attained board certification in each specialty. He served in the US Army Occupation Force Medical Corps in Germany just after World War II. In 1957, at 37 years old, he assumed the chairmanship of the orthopaedic training program at the University of Kansas. In 1971, he couldn't resist the opportunity to become one of the founding members of the "start-up" University of Arizona College of Medicine, accepting an appointment as chair of the new orthopaedic training program, where he remained until his retirement in 1990. He took clinical problems to the laboratory, and made important scientific contributions, particularly in the area of fat embolism and in using calcium sulfate (plaster of Paris) to fill bone defects. He served on governing boards of national professional organizations and presided over the American Association for the Surgery of Trauma from 1980-1981. Throughout his career, he was fascinated by, and published extensively in, the history of medicine arena. Known fondly as "the professor" to many of his residents and colleagues, he had a pragmatic, honest, upbeat, and often humorous approach to life's challenges, valuing personal integrity above other virtues. He explored various eclectic interests far beyond his professional contributions while maintaining his family as a central priority. With his exemplary productivity and interests in the surgical and laboratory sciences, history of medicine, appreciation of fine arts, and perceptive and effective interactions with family, friends, patients, and colleagues, the memory of Leonard

  15. MS PHD'S Professional Development Program: A Scientific Renaissance in Cyberspace

    Science.gov (United States)

    Powell, J. M.; Williamson, V. A.; Griess, C. A.; Pyrtle, A. J.

    2004-12-01

    This study is a component of a four-year investigation of MS PHD'S Professional Development Program's virtual community through the lenses of underrepresented minority students in Earth system science and engineering fields. In this presentation, the development, assessment and projected utilization of the ongoing study will be discussed. The overall goal of this study is to examine the effectiveness of virtual team building methods and understand how the development of a communal cyberinfrastructure acts as an integral part of the emergence of a Scientific Renaissance. The exemplar, Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S), provides professional development experiences to facilitate the advancement of students of color achieving outstanding Earth system careers. Undergraduate and graduate students are supported through access to scientific conferences, mentorship and virtual community building. Framed by critical theory, this ethnographic exploration uses a mixed methods research design to record, observe, and analyze both the processes and products of the website, listserv and synchronous web-based dialogue. First, key findings of the formative evaluation and annual reports of the successfully implemented 2003 MS PHD'S Pilot Project are presented. These findings inform future evaluations of the use of technological resources and illustrate how this public space provides peer support and enriched research opportunities. Quantitative methods such as statistical analysis, academic and professional tracking and evaluative tools for scientific content and competency are complimented by qualitative methods that include observations, heuristic case studies and focus group interviews. The findings of this ongoing investigation will provide insight on how national organizations, higher education practitioners, community-based support systems and underrepresented minorities in the sciences promote diversity by developing

  16. Expanded radio art as PhD practice

    OpenAIRE

    Hall, M.

    2015-01-01

    Radio After Radio: Redefining Radio Art in the Light of New Media Technology through Expanded Practice is the title of my PhD practice based research. This paper focuses on the extended boundaries of radio art, considering how radio art might be defined in relation to sound art, music, and media art. Mapping the shifting parameters of radio art in the digital era has prompted a consideration of how radio can be seen to be moving from being a predominantly shared "live" event to one consumed "...

  17. Hrvoje Tomić, PhD in Technical Sciences

    Directory of Open Access Journals (Sweden)

    Siniša Mastelić Ivić

    2010-12-01

    Full Text Available Hrvoje Tomić defended his PhD thesis Geospatial Data Analysis for the Purpose of Real Estate Valuation in Urban Areas at the Faculty of Geodesy, University of Zagreb, on November 15, 2010. His mentor was Prof. Dr. Siniša Mastelić Ivić, and the other two members of the Grading and Defence Committee were Assist. Prof. Dr. Vlado Cetl and Prof. Dr. Goran Poljanec from the Faculty of Civil Engineering, University of Zagreb.

  18. Filter quality of pleated filter cartridges.

    Science.gov (United States)

    Chen, Chun-Wan; Huang, Sheng-Hsiu; Chiang, Che-Ming; Hsiao, Ta-Chih; Chen, Chih-Chieh

    2008-04-01

    The performance of dust cartridge filters commonly used in dust masks and in room ventilation depends both on the collection efficiency of the filter material and the pressure drop across the filter. Currently, the optimization of filter design is based only on minimizing the pressure drop at a set velocity chosen by the manufacturer. The collection efficiency, an equally important factor, is rarely considered in the optimization process. In this work, a filter quality factor, which combines the collection efficiency and the pressure drop, is used as the optimization criterion for filter evaluation. Most respirator manufacturers pleat the filter to various extents to increase the filtration area in the limit space within the dust cartridge. Six sizes of filter holders were fabricated to hold just one pleat of filter, simulating six different pleat counts, ranging from 0.5 to 3.33 pleats cm(-1). The possible electrostatic charges on the filter were removed by dipping in isopropyl alcohol, and the air velocity is fixed at 100 cm s(-1). Liquid dicotylphthalate particles generated by a constant output atomizer were used as challenge aerosols to minimize particle loading effects. A scanning mobility particle sizer was used to measure the challenge aerosol number concentrations and size distributions upstream and downstream of the pleated filter. The pressure drop across the filter was monitored by using a calibrated pressure transducer. The results showed that the performance of pleated filters depend not only on the size of the particle but also on the pleat count of the pleated filter. Based on filter quality factor, the optimal pleat count (OPC) is always higher than that based on pressure drop by about 0.3-0.5 pleats cm(-1). For example, the OPC is 2.15 pleats cm(-1) from the standpoint of pressure drop, but for the highest filter quality factor, the pleated filter needed to have a pleat count of 2.65 pleats cm(-1) at particle diameter of 122 nm. From the aspect of

  19. Bird community response to filter strips in Maryland

    Science.gov (United States)

    Blank, P.J.; Dively, G.P.; Gill, D.E.; Rewa, C.A.

    2011-01-01

    Filter strips are strips of herbaceous vegetation planted along agricultural field margins adjacent to streams or wetlands and are designed to intercept sediment, nutrients, and agrichemicals. Roughly 16,000 ha of filter strips have been established in Maryland through the United States Department of Agriculture's Conservation Reserve Enhancement Program. Filter strips often represent the only uncultivated herbaceous areas on farmland in Maryland and therefore may be important habitat for early-successional bird species. Most filter strips in Maryland are planted to either native warm-season grasses or cool-season grasses and range in width from 10.7 m to 91.4 m. From 2004 to 2007 we studied the breeding and wintering bird communities in filter strips adjacent to wooded edges and non-buffered field edges and the effect that grass type and width of filter strips had on bird community composition. We used 5 bird community metrics (total bird density, species richness, scrub-shrub bird density, grassland bird density, and total avian conservation value), species-specific densities, nest densities, and nest survival estimates to assess the habitat value of filter strips for birds. Breeding and wintering bird community metrics were greater in filter strips than in non-buffered field edges but did not differ between cool-season and warm-season grass filter strips. Most breeding bird community metrics were negatively related to the percent cover of orchardgrass (Dactylis glomerata) in ???1 yr. Breeding bird density was greater in narrow (60 m) filter strips. Our results suggest that narrow filter strips adjacent to wooded edges can provide habitat for many bird species but that wide filter strips provide better habitat for grassland birds, particularly obligate grassland species. If bird conservation is an objective, avoid planting orchardgrass in filter strips and reduce or eliminate orchardgrass from filter strips through management practices. Copyright ?? 2011 The

  20. Exploring PHD fingers and H3K4me0 interactions with molecular dynamics simulations and binding free energy calculations: AIRE-PHD1, a comparative study.

    Directory of Open Access Journals (Sweden)

    Dimitrios Spiliotopoulos

    Full Text Available PHD fingers represent one of the largest families of epigenetic readers capable of decoding post-translationally modified or unmodified histone H3 tails. Because of their direct involvement in human pathologies they are increasingly considered as a potential therapeutic target. Several PHD/histone-peptide structures have been determined, however relatively little information is available on their dynamics. Studies aiming to characterize the dynamic and energetic determinants driving histone peptide recognition by epigenetic readers would strongly benefit from computational studies. Herein we focus on the dynamic and energetic characterization of the PHD finger subclass specialized in the recognition of histone H3 peptides unmodified in position K4 (H3K4me0. As a case study we focused on the first PHD finger of autoimmune regulator protein (AIRE-PHD1 in complex with H3K4me0. PCA analysis of the covariance matrix of free AIRE-PHD1 highlights the presence of a "flapping" movement, which is blocked in an open conformation upon binding to H3K4me0. Moreover, binding free energy calculations obtained through Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA methodology are in good qualitative agreement with experiments and allow dissection of the energetic terms associated with native and alanine mutants of AIRE-PHD1/H3K4me0 complexes. MM/PBSA calculations have also been applied to the energetic analysis of other PHD fingers recognizing H3K4me0. In this case we observe excellent correlation between computed and experimental binding free energies. Overall calculations show that H3K4me0 recognition by PHD fingers relies on compensation of the electrostatic and polar solvation energy terms and is stabilized by non-polar interactions.

  1. AIRE-PHD fingers are structural hubs to maintain the integrity of chromatin-associated interactome.

    Science.gov (United States)

    Gaetani, Massimiliano; Matafora, Vittoria; Saare, Mario; Spiliotopoulos, Dimitrios; Mollica, Luca; Quilici, Giacomo; Chignola, Francesca; Mannella, Valeria; Zucchelli, Chiara; Peterson, Pärt; Bachi, Angela; Musco, Giovanna

    2012-12-01

    Mutations in autoimmune regulator (AIRE) gene cause autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. AIRE is expressed in thymic medullary epithelial cells, where it promotes the expression of peripheral-tissue antigens to mediate deletional tolerance, thereby preventing self-reactivity. AIRE contains two plant homeodomains (PHDs) which are sites of pathological mutations. AIRE-PHD fingers are important for AIRE transcriptional activity and presumably play a crucial role in the formation of multimeric protein complexes at chromatin level which ultimately control immunological tolerance. As a step forward the understanding of AIRE-PHD fingers in normal and pathological conditions, we investigated their structure and used a proteomic SILAC approach to assess the impact of patient mutations targeting AIRE-PHD fingers. Importantly, both AIRE-PHD fingers are structurally independent and mutually non-interacting domains. In contrast to D297A and V301M on AIRE-PHD1, the C446G mutation on AIRE-PHD2 destroys the structural fold, thus causing aberrant AIRE localization and reduction of AIRE target genes activation. Moreover, mutations targeting AIRE-PHD1 affect the formation of a multimeric protein complex at chromatin level. Overall our results reveal the importance of AIRE-PHD domains in the interaction with chromatin-associated nuclear partners and gene regulation confirming the role of PHD fingers as versatile protein interaction hubs for multiple binding events.

  2. Composing morphological filters

    NARCIS (Netherlands)

    H.J.A.M. Heijmans (Henk)

    1995-01-01

    textabstractA morphological filter is an operator on a complete lattice which is increasing and idempotent. Two well-known classes of morphological filters are openings and closings. Furthermore, an interesting class of filters, the alternating sequential filters, is obtained if one composes openin

  3. Composing morphological filters

    NARCIS (Netherlands)

    Heijmans, H.J.A.M.

    1995-01-01

    A morphological filter is an operator on a complete lattice which is increasing and idempotent. Two well-known classes of morphological filters are openings and closings. Furthermore, an interesting class of filters, the alternating sequential filters, is obtained if one composes openings and closi

  4. Passive Power Filters

    CERN Document Server

    Künzi, R

    2015-01-01

    Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

  5. I-determinants for a successful PhD or postdoctoral outcome.

    Science.gov (United States)

    Sørensen, Henrik Toft

    2016-01-01

    Many resources are invested in research training, but very little literature exists on predictors for a successful PhD and postdoctoral training outcome. A PhD program has two overall objectives: to extend knowledge about a hopefully important health topic and to provide extensive training to improve the PhD student's skills through learning research methods and collaboration. A substantial number of PhD students may run into some kind of problem in the course of their PhD program. In this article, some determinants all starting with an "I" and indicative of a good PhD outcome are reported. The successful PhD student can be described as having an Interest in the PhD program, an Incentive for the program, and an Idea of what he or she wants to investigate, showing Initiative, and having high personal Integrity and good Interpersonal relationships. When these so-called I-determinants are present, the likelihood of success in a PhD program is high. More evidence is available for selection of candidates for postdoctoral appointments since it is known that the postdoctoral candidate has completed a PhD program, published papers in peer-reviewed journals, and received awarded grants. However, other characteristics determine a successful transition of the postdoctoral candidate into a research leader. These determinants are Identity, Independence and Image, Implementation ability in terms of being able to implement decisions and projects, working with Innovative and Important topics, having In-depth knowledge of the research topic, being Interactive and Integrated with the scientific community, and Internationally oriented. In conclusion, regardless of the framework of research, the personal characteristics of a researcher play a very important role in the quality of research. Application of some of the principles mentioned in this article might allow decision to reach a more evidence-based way to recruit PhD students and postdoctorals.

  6. Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S) Beyond the PhD Professional Development Program: A Pilot Project

    Science.gov (United States)

    Johnson, A.; Jearld, A.; Williamson Whitney, V.; Huggans, M.; Ricciardi, L.; Thomas, S. H.; Jansma, P. E.

    2012-12-01

    In 2011 the Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S)® initiative launched its newest activity entitled the MS PHD'S "Beyond the PhD (B-PhD) Professional Development Program." This exciting new program was designed to facilitate the development of a new community of underrepresented minority (URM) doctoral candidates and recent doctorate degree recipients in Earth system science (ESS)-related fields. The MS PHD'S B-PhD provides customized support and advocacy for MS PHD'S B-PhD participants in order to facilitate smoother and informed transitions from graduate school, to postdoctoral and tenure-track positions, as well as other "first" jobs in government, industry, and non-profit organizations. In November 2011 the first cohort of MS PHD'S B-PhD participants engaged in intensive sessions on the following topics: "Toolkits for Success for Academia, Business/Industry, Federal Government and Non-Profits", "Defining Short, Mid and Long Term Career Goals", "Accessing and Refining Skill Sets and Other Door Openers", "International Preparation and Opportunities", "Paying it Forward/Lifting as You Climb", and "Customized Strategies for Next Steps". This pilot event, which was hosted by the University of Texas at Arlington's (UTA) College of Science, also provided opportunities for participants to serve as guest lecturers in the UTA's Colleges of Science and Engineering and included one-on-one discussions with MS PHD'S B-PhD mentors and guest speakers who are well established within their individual ESS fields. Insights regarding opportunities, challenges and obstacles commonly faced by URMs within the ESS fields, as well as strategies for success were shared by MS PHD'S B-PhD mentors and guest speakers. Survey results indicate that MS PHD'S B-PhD participants appreciated not only the material covered during this pilot activity, but also appreciated the opportunity to become part of a community of young URM ESS

  7. Method of securing filter elements

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Erik P.; Haslam, Jeffery L.; Mitchell, Mark A.

    2016-10-04

    A filter securing system including a filter unit body housing; at least one tubular filter element positioned in the filter unit body housing, the tubular filter element having a closed top and an open bottom; a dimple in either the filter unit body housing or the top of the tubular filter element; and a socket in either the filter unit body housing or the top of the tubular filter element that receives the dimple in either the filter unit body housing or the top of the tubular filter element to secure the tubular filter element to the filter unit body housing.

  8. Si-based infrared optical filters

    Science.gov (United States)

    Balčytis, Armandas; Ryu, Meguya; Seniutinas, Gediminas; Nishijima, Yoshiaki; Hikima, Yuta; Zamengo, Massimiliano; Petruškevičius, Raimondas; Morikawa, Junko; Juodkazis, Saulius

    2015-12-01

    Pyramidal silicon nanospikes, termed black-Si (b-Si), with controlled height of 0.2 to 1 μm, were fabricated by plasma etching over 3-in wafers and were shown to act as variable density filters in a wide range of the IR spectrum 2.5 to 20 μm, with transmission and its spectral gradient dependent on the height of the spikes. Such variable density IR filters can be utilized for imaging and monitoring applications. Narrow IR notch filters were realized with gold mesh arrays on Si wafers prospective for applications in surface-enhanced IR absorption sensing and "cold materials" for heat radiation into atmospheric IR transmission window. Both types of filters for IR: spectrally variable and notch are made by simple fabrication methods.

  9. Research(er) at Home: Auto/Ethnography of (My) PhD

    Science.gov (United States)

    Benová, Kamila

    2014-01-01

    This article deals with the PhD phase of tertiary higher education (in Slovakia), which is here considered as the specific phase of the academic career. It tries to answer the question: what is the PhD, in the context of research, theoretically and methodologically approached as a critical ethnography of higher education. It is focused on the…

  10. Enhancing the Industrial PhD Programme as a Policy Tool for University-Industry Cooperation

    Science.gov (United States)

    Roolaht, Tõnu

    2015-01-01

    The changing role of universities in society includes the increasing expectation that academic institutions should engage in collaboration with companies. Industrial PhD programmes are educational tools for building bridges between the academic sector and industry. In these programmes, the PhD student studies and carries out research while being…

  11. Enhancing the Industrial PhD Programme as a Policy Tool for University-Industry Cooperation

    Science.gov (United States)

    Roolaht, Tõnu

    2015-01-01

    The changing role of universities in society includes the increasing expectation that academic institutions should engage in collaboration with companies. Industrial PhD programmes are educational tools for building bridges between the academic sector and industry. In these programmes, the PhD student studies and carries out research while being…

  12. Intercultural PhD Supervision: Exploring the Hidden Curriculum in a Social Science Faculty Doctoral Programme

    Science.gov (United States)

    Kidman, Joanna; Manathunga, Catherine; Cornforth, Sue

    2017-01-01

    International knowledge markets rely heavily on a ready supply of highly mobile doctoral students, many of whom are from the global South, to bring in revenue. The supervision of these PhD students, however, can reproduce neo-colonial knowledge relations, often in subtle ways. In settler nations, international PhD students may find that they are…

  13. Creating Entrepreneurial Networks: Academic Entrepreneurship, Mobility and Collaboration during PhD Education

    Science.gov (United States)

    Bienkowska, Dzamila; Klofsten, Magnus

    2012-01-01

    Network-building activities of PhD students are an important area of study in furthering our understanding of academic entrepreneurship. This paper focuses on PhD students' participation in network-building activities defined as mobility and collaboration, as well as own interest in and perceived grade of support for commercialisation from various…

  14. Searching for "A Third Space": A Creative Pathway towards International PhD Students' Academic Acculturation

    Science.gov (United States)

    Elliot, Dely Lazarte; Baumfield, Vivienne; Reid, Kate

    2016-01-01

    Undertaking a PhD is a challenging endeavour. Pursuing a doctoral education in a "foreign" context tends to increase the demands of this intellectual venture. The nature of research-based PhD programmes, often characterised by a lack of formal curricula where academic supervision lasts several years, may add another layer of complexity.…

  15. Self-efficacy is related to PhD completion time: possible tool for interventions

    NARCIS (Netherlands)

    Bouma, Esther

    2015-01-01

    Every two years the University of Groningen evaluates PhD' satisfaction concerning education and working environment. The goal is to create an environment in which PhD's can develop the necessary research skills for their projects as well as finish these projects in time. At Dutch universities most

  16. The Undergraduate Origins of PhD Economists: The Berkeley Experience

    Science.gov (United States)

    Olney, Martha L.

    2015-01-01

    The University of California, Berkeley sends more undergraduate students to economics PhD programs than any other public university. While this fact is surely a function of its size, there may be lessons from the Berkeley experience that others could adopt. To investigate why Berkeley generates so many economics PhD students, the author convened…

  17. A Controlled Particle Filter for Global Optimization

    OpenAIRE

    Zhang, Chi; Taghvaei, Amirhossein; Mehta, Prashant G.

    2017-01-01

    A particle filter is introduced to numerically approximate a solution of the global optimization problem. The theoretical significance of this work comes from its variational aspects: (i) the proposed particle filter is a controlled interacting particle system where the control input represents the solution of a mean-field type optimal control problem; and (ii) the associated density transport is shown to be a gradient flow (steepest descent) for the optimal value function, with respect to th...

  18. Tunability of Nonuniform Reflection Holographic Filter

    Institute of Scientific and Technical Information of China (English)

    Shanhong You(游善红); Xinwan Li(李新碗); Jianhong Wu(吴建宏); Zongmin Yin(殷宗敏); Minxue Tang(唐敏学)

    2003-01-01

    The tunability of nonuniform reflection holographic filter is investigated theoretically and experimentally. It is shown that the reflection holographic filter has not only high optical density and narrow bandwidth, but also good tunability. The coupled wave theoretical model for uniform medium is compared with the model for nonuniform medium. It is identified that the coincidence of the theoretical results of the nonuniform model with the experimental results are better than that of the uniform model.

  19. The Virtual Observatory Powered PhD Thesis

    CERN Document Server

    Zolotukhin, Ivan

    2010-01-01

    The Virtual Observatory has reached sufficient maturity for its routine scientific exploitation by astronomers. To prove this statement, here I present a brief description of the complete VO-powered PhD thesis entitled "Galactic and extragalactic research with modern surveys and the Virtual Observatory" comprising 4 science cases covering various aspects of astrophysical research. These comprize: (1) homogeneous search and measurement of main physical parameters of Galactic open star clusters in huge multi-band photometric surveys; (2) study of optical-to-NIR galaxy colors using a large homogeneous dataset including spectroscopy and photometry from SDSS and UKIDSS; (3) study of faint low-mass X-ray binary population in modern observational archives; (4) search for optical counterparts of unidentified X-ray objects with large positional uncertainties in the Galactic Plane. All these projects make heavy use of the VO technologies and tools and would not be achievable without them. So refereed papers published i...

  20. PHD2: from hypoxia regulation to disease progression.

    Science.gov (United States)

    Meneses, Ana M; Wielockx, Ben

    2016-01-01

    Oxygen represents one of the major molecules required for the development and maintenance of life. An adequate response to hypoxia is therefore required for the functioning of the majority of living organisms and relies on the activation of the hypoxia-inducible factor (HIF) pathway. HIF prolyl hydroxylase domain-2 (PHD2) has long been recognized as the major regulator of this response, controlling a myriad of outcomes that range from cell death to proliferation. However, this enzyme has been associated with more pathways, making the role of this protein remarkably complex under distinct pathologies. While a protective role seems to exist in physiological conditions such as erythropoiesis; the picture is more complex during pathologies such as cancer. Since the regulation of this enzyme and its closest family members is currently considered as a possible therapy for various diseases, understanding the different particular roles of this protein is essential.

  1. On M. Mueter's Ph.D. Thesis on Cheeger deformations

    CERN Document Server

    Ziller, Wolfgang

    2009-01-01

    These are notes of a talk I gave in a seminar at the University of Pennsylvania summarizing results in the Ph.D. thesis of Michael Mueter obtained under the direction of Wolfgang Meyer at the University of Muenster. His thesis on "Kruemmungserhoehende Deformationen mittels Gruppenaktionen" examines in detail curvature properties of so called Cheeger deformations. Such deformations have been a crucial ingredient in non-negative and positive curvature constructions. His thesis contains a wealth of interesting properties of such deformations, but since it was never published, is only known to a few experts. I have no intention to publish these notes, but post them as a service to the public. A scanned version of his thesis (written in German) is available on my homepage.

  2. PhD Thesis: Functional Textiles in Hospital Interiors

    DEFF Research Database (Denmark)

    Mogensen, Jeppe Emil

    consists of a collection of 5 peer-reviewed papers, and an extended summary. The project is overall related to the construction of new Danish hospitals, where the design concept healing architecture is intro- duced in a national context, representing the vision of a promoted healing process of hospitalised...... of plastic, vinyl and steel. These materials also dominate the new hospitals, designed and constructed these years, and despite the increased focus on the design concept healing architecture, the rational requirements of ef cient cleaning and maintenance still seems to direct the interior design of hospital...... of this PhD project has been to explore the possibilities and design qualities of using these materials in hospital inte- rior design. Relating to both technical and aesthetic aspects of using functional textiles in hospitals, the project seeks to integrate these aspects, departing from the overall research...

  3. Researcher Profile: An Interview with Jodi Letkiewicz, Ph.D.

    Directory of Open Access Journals (Sweden)

    Jodi Letkiewicz

    2014-12-01

    Full Text Available Jodi Letkiewicz, Ph.D., is an assistant professor of finance at York University in Toronto, Ontario. She teaches in the Certified Financial Planner® Core Curriculum program preparing undergraduate students for the Canadian CFP® certification and conducts research in several areas of personal finance and consumer decision-making, including behavioral aspects influencing the decision to seek financial help, how personality traits affect financial decision-making, and the financial state of young adults, including the impact student loans have on overall well-being and financial milestones early in their adult life. Dr. Letkiewicz’s goal is to increase financial well-being in the general public, which she hopes to accomplish through teaching, research, and community outreach.

  4. Attitude of PhD Students Towards Academic Dishonesty

    Directory of Open Access Journals (Sweden)

    Vilija Grincevičienė

    2011-04-01

    Full Text Available The article describes the problem of academic dishonesty. Looking over the results of research done in foreign countries (the USA, Romania, Poland, it is possible to assert that the ethics of a scientist is a topical problem nowadays not only in Lithuania but also all over the world. The results of pilot research show that although in all curricula, textbooks and other sources it is declared that each researcher or a team must keep to certain ethics rules, not everything goes well. Respondents were first year PhD students of Vilnius Gediminas Technical University (N=51. Taking into account the results, more attention should be paid to the analysis and correction of the situation.

  5. Analysis list: ph-d [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ph-d Cell line,Embryo + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/p...h-d.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/ph-d.5.tsv http://dbarchive.biosciencedbc.jp.../kyushu-u/dm3/target/ph-d.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/ph-d.Cell_line.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/colo/ph-d.Embryo.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/colo/Cell_line.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Embryo.gml ...

  6. Generalized Hampel Filters

    Science.gov (United States)

    Pearson, Ronald K.; Neuvo, Yrjö; Astola, Jaakko; Gabbouj, Moncef

    2016-12-01

    The standard median filter based on a symmetric moving window has only one tuning parameter: the window width. Despite this limitation, this filter has proven extremely useful and has motivated a number of extensions: weighted median filters, recursive median filters, and various cascade structures. The Hampel filter is a member of the class of decsion filters that replaces the central value in the data window with the median if it lies far enough from the median to be deemed an outlier. This filter depends on both the window width and an additional tuning parameter t, reducing to the median filter when t=0, so it may be regarded as another median filter extension. This paper adopts this view, defining and exploring the class of generalized Hampel filters obtained by applying the median filter extensions listed above: weighted Hampel filters, recursive Hampel filters, and their cascades. An important concept introduced here is that of an implosion sequence, a signal for which generalized Hampel filter performance is independent of the threshold parameter t. These sequences are important because the added flexibility of the generalized Hampel filters offers no practical advantage for implosion sequences. Partial characterization results are presented for these sequences, as are useful relationships between root sequences for generalized Hampel filters and their median-based counterparts. To illustrate the performance of this filter class, two examples are considered: one is simulation-based, providing a basis for quantitative evaluation of signal recovery performance as a function of t, while the other is a sequence of monthly Italian industrial production index values that exhibits glaring outliers.

  7. Prolyl-4-hydroxylase 3 (PHD3 expression is downregulated during epithelial-to-mesenchymal transition.

    Directory of Open Access Journals (Sweden)

    Trenton L Place

    Full Text Available Prolyl-4-hydroxylation by the intracellular prolyl-4-hydroxylase enzymes (PHD1-3 serves as a master regulator of environmental oxygen sensing. The activity of these enzymes is tightly tied to tumorigenesis, as they regulate cell metabolism and angiogenesis through their control of hypoxia-inducible factor (HIF stability. PHD3 specifically, is gaining attention for its broad function and rapidly accumulating array of non-HIF target proteins. Data from several recent studies suggest a role for PHD3 in the regulation of cell morphology and cell migration. In this study, we aimed to investigate this role by closely examining the relationship between PHD3 expression and epithelial-to-mesenchymal transition (EMT; a transcriptional program that plays a major role in controlling cell morphology and migratory capacity. Using human pancreatic ductal adenocarcinoma (PDA cell lines and Madin-Darby Canine Kidney (MDCK cells, we examined the correlation between several markers of EMT and PHD3 expression. We demonstrated that loss of PHD3 expression in PDA cell lines is highly correlated with a mesenchymal-like morphology and an increase in cell migratory capacity. We also found that induction of EMT in MDCK cells resulted in the specific downregulation of PHD3, whereas the expression of the other HIF-PHD enzymes was not affected. The results of this study clearly support a model by which the basal expression and hypoxic induction of PHD3 is suppressed by the EMT transcriptional program. This may be a novel mechanism by which migratory or metastasizing cells alter signaling through specific pathways that are sensitive to regulation by O2. The identification of downstream pathways that are affected by the suppression of PHD3 expression during EMT may provide important insight into the crosstalk between O2 and the migratory and metastatic potential of tumor cells.

  8. MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing

    DEFF Research Database (Denmark)

    2014-01-01

    MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing......MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing...

  9. MST Filterability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-12

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO2, and NaNO3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

  10. Guided image filtering.

    Science.gov (United States)

    He, Kaiming; Sun, Jian; Tang, Xiaoou

    2013-06-01

    In this paper, we propose a novel explicit image filter called guided filter. Derived from a local linear model, the guided filter computes the filtering output by considering the content of a guidance image, which can be the input image itself or another different image. The guided filter can be used as an edge-preserving smoothing operator like the popular bilateral filter [1], but it has better behaviors near edges. The guided filter is also a more generic concept beyond smoothing: It can transfer the structures of the guidance image to the filtering output, enabling new filtering applications like dehazing and guided feathering. Moreover, the guided filter naturally has a fast and nonapproximate linear time algorithm, regardless of the kernel size and the intensity range. Currently, it is one of the fastest edge-preserving filters. Experiments show that the guided filter is both effective and efficient in a great variety of computer vision and computer graphics applications, including edge-aware smoothing, detail enhancement, HDR compression, image matting/feathering, dehazing, joint upsampling, etc.

  11. Epidermal or dermal specific knockout of PHD-2 enhances wound healing and minimizes ischemic injury.

    Directory of Open Access Journals (Sweden)

    Andrew S Zimmermann

    Full Text Available INTRODUCTION: Hypoxia-inducible factor (HIF-1α, part of the heterodimeric transcription factor that mediates the cellular response to hypoxia, is critical for the expression of multiple angiogenic growth factors, cell motility, and the recruitment of endothelial progenitor cells. Inhibition of the oxygen-dependent negative regulator of HIF-1α, prolyl hydroxylase domain-2 (PHD-2, leads to increased HIF-1α and mimics various cellular and physiological responses to hypoxia. The roles of PHD-2 in the epidermis and dermis have not been clearly defined in wound healing. METHODS: Epidermal and dermal specific PHD-2 knockout (KO mice were developed in a C57BL/6J (wild type background by crossing homozygous floxed PHD-2 mice with heterozygous K14-Cre mice and heterozygous Col1A2-Cre-ER mice to get homozygous floxed PHD-2/heterozygous K14-Cre and homozygous floxed PHD-2/heterozygous floxed Col1A2-Cre-ER mice, respectively. Ten to twelve-week-old PHD-2 KO and wild type (WT mice were subjected to wounding and ischemic pedicle flap model. The amount of healing was grossly quantified with ImageJ software. Western blot and qRT-PCR was run on protein and RNA from primary cells cultured in vitro. RESULTS: qRT-PCR demonstrated a significant decrease of PHD-2 in keratinocytes and fibroblasts derived from tissue specific KO mice relative to control mice (*p<0.05. Western blot analysis showed a significant increase in HIF-1α and VEGF protein levels in PHD-2 KO mice relative to control mice (*p<0.05. PHD-2 KO mice showed significantly accelerated wound closure relative to WT (*p<0.05. When ischemia was analyzed at day nine post-surgery in a flap model, the PHD-2 tissue specific knockout mice showed significantly more viable flaps than WT (*p<0.05. CONCLUSIONS: PHD-2 plays a significant role in the rates of wound healing and response to ischemic insult in mice. Further exploration shows PHD-2 KO increases cellular levels of HIF-1α and this increase leads to the

  12. Shaping of light beams with photonic crystals : spatial filtering, beam collimation and focusing

    OpenAIRE

    2014-01-01

    The research developed in the framework of this PhD thesis is a theoretical, numerical and experimental study of light beam shaping (spatial filtering, beam collimation and focusing) in the visible frequency range using photonic crystal structures. Photonic crystals (PhCs) are materials with periodic, spatially modulated refractive index on the wavelength scale. They are primarily known for their chromatic dispersion properties. However, they can also modify the spatial dispersion, which allo...

  13. Analysis of PhD study at the Medical Faculty, University of Ljubljana, in the years 1995–2010

    Directory of Open Access Journals (Sweden)

    Danijel Petrovič

    2012-12-01

    Full Text Available Besides teaching, research is one of the main activities of the Faculty of Medicine of the University of Ljubljana. Since 1995, the PhD study at the Faculty of Medicine has been organized via the Biomedicine university programme. The authors performed the analysis of the quality of Biomedicine PhD study at the Faculty of Medicine between the years 1995 and 2010. The authors were interested in the number of PhD students that started and finished their PhD studies and how successful PhD students were during that period (how many papers they wrote on the topic of the PhD and what was the impact factor of the papers. In the 15-year period from 1995–2010, 702 students started the Biomedicine PhD programme, while 652 students completed it. Most PhD students (70.7 % have written one SCI paper related to the thesis. Finally, the medium impact factor of the SCI paper related to the PhD thesis was 2.6. We may conclude that the quality of PhD theses evaluated according to the impact factor of the SCI papers related to the theses is solid, however our strength should be aimed toward the continuous increase of quality. In this regard, PhD candidates, mentors as well as the commission for the evaluation of PhD theses must do their homework diligently.

  14. Computer Aided Filter Design.

    Science.gov (United States)

    1987-12-01

    FIR filter can be described in the following. [Ref. 2] 1. FIR filters with exact linear phase can be easily designed. Linear phase filters are important...response for the four cases of linear phase filter , i.e., even or odd symmetry with an even or odd number of terms, can be written in the form: H (eJ ) = e...Ansari, The Design and Application of Optimal FIR Fractional Phase Filters , IEEE on Acoutics, Speech and Signal Processing, Vol. 2, 1987, pp.896-899. 77 14

  15. A unified Kalman filter

    Science.gov (United States)

    Stubberud, Allen R.

    2017-01-01

    When considering problems of linear sequential estimation, two versions of the Kalman filter, the continuous-time version and the discrete-time version, are often used. (A hybrid filter also exists.) In many applications in which the Kalman filter is used, the system to which the filter is applied is a linear continuous-time system, but the Kalman filter is implemented on a digital computer, a discrete-time device. The two general approaches for developing a discrete-time filter for implementation on a digital computer are: (1) approximate the continuous-time system by a discrete-time system (called discretization of the continuous-time system) and develop a filter for the discrete-time approximation; and (2) develop a continuous-time filter for the system and then discretize the continuous-time filter. Generally, the two discrete-time filters will be different, that is, it can be said that discretization and filter generation are not, in general, commutative operations. As a result, any relationship between the discrete-time and continuous-time versions of the filter for the same continuous-time system is often obfuscated. This is particularly true when an attempt is made to generate the continuous-time version of the Kalman filter through a simple limiting process (the sample period going to zero) applied to the discrete-time version. The correct result is, generally, not obtained. In a 1961 research report, Kalman showed that the continuous-time Kalman filter can be obtained from the discrete-time Kalman filter by taking limits as the sample period goes to zero if the white noise process for the continuous-time version is appropriately defined. Using this basic concept, a discrete-time Kalman filter can be developed for a continuous-time system as follows: (1) discretize the continuous-time system using Kalman's technique; and (2) develop a discrete-time Kalman filter for that discrete-time system. Kalman's results show that the discrete-time filter generated in

  16. Bias aware Kalman filters

    DEFF Research Database (Denmark)

    Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

    2006-01-01

    . The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved....

  17. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  18. Tracking Multiple Video Targets with an Improved GM-PHD Tracker

    Directory of Open Access Journals (Sweden)

    Xiaolong Zhou

    2015-12-01

    Full Text Available Tracking multiple moving targets from a video plays an important role in many vision-based robotic applications. In this paper, we propose an improved Gaussian mixture probability hypothesis density (GM-PHD tracker with weight penalization to effectively and accurately track multiple moving targets from a video. First, an entropy-based birth intensity estimation method is incorporated to eliminate the false positives caused by noisy video data. Then, a weight-penalized method with multi-feature fusion is proposed to accurately track the targets in close movement. For targets without occlusion, a weight matrix that contains all updated weights between the predicted target states and the measurements is constructed, and a simple, but effective method based on total weight and predicted target state is proposed to search the ambiguous weights in the weight matrix. The ambiguous weights are then penalized according to the fused target features that include spatial-colour appearance, histogram of oriented gradient and target area and further re-normalized to form a new weight matrix. With this new weight matrix, the tracker can correctly track the targets in close movement without occlusion. For targets with occlusion, a robust game-theoretical method is used. Finally, the experiments conducted on various video scenarios validate the effectiveness of the proposed penalization method and show the superior performance of our tracker over the state of the art.

  19. Tracking Multiple Video Targets with an Improved GM-PHD Tracker.

    Science.gov (United States)

    Zhou, Xiaolong; Yu, Hui; Liu, Honghai; Li, Youfu

    2015-12-03

    Tracking multiple moving targets from a video plays an important role in many vision-based robotic applications. In this paper, we propose an improved Gaussian mixture probability hypothesis density (GM-PHD) tracker with weight penalization to effectively and accurately track multiple moving targets from a video. First, an entropy-based birth intensity estimation method is incorporated to eliminate the false positives caused by noisy video data. Then, a weight-penalized method with multi-feature fusion is proposed to accurately track the targets in close movement. For targets without occlusion, a weight matrix that contains all updated weights between the predicted target states and the measurements is constructed, and a simple, but effective method based on total weight and predicted target state is proposed to search the ambiguous weights in the weight matrix. The ambiguous weights are then penalized according to the fused target features that include spatial-colour appearance, histogram of oriented gradient and target area and further re-normalized to form a new weight matrix. With this new weight matrix, the tracker can correctly track the targets in close movement without occlusion. For targets with occlusion, a robust game-theoretical method is used. Finally, the experiments conducted on various video scenarios validate the effectiveness of the proposed penalization method and show the superior performance of our tracker over the state of the art.

  20. I-determinants for a successful PhD or postdoctoral outcome

    Directory of Open Access Journals (Sweden)

    Sørensen HT

    2016-08-01

    Full Text Available Henrik Toft Sørensen1–3 1Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark; 2Department of Health Research and Policy, 3Stanford’s Center for Advanced Study in Behavioral Sciences, Stanford University, Stanford, CA, USA Abstract: Many resources are invested in research training, but very little literature exists on predictors for a successful PhD and postdoctoral training outcome. A PhD program has two overall objectives: to extend knowledge about a hopefully important health topic and to provide extensive training to improve the PhD student’s skills through learning research methods and collaboration. A substantial number of PhD students may run into some kind of problem in the course of their PhD program. In this article, some determinants all starting with an “I” and indicative of a good PhD outcome are reported. The successful PhD student can be described as having an Interest in the PhD program, an Incentive for the program, and an Idea of what he or she wants to investigate, showing Initiative, and having high personal Integrity and good Interpersonal relationships. When these so-called I-determinants are present, the likelihood of success in a PhD program is high. More evidence is available for selection of candidates for postdoctoral appointments since it is known that the postdoctoral candidate has completed a PhD program, published papers in peer-reviewed journals, and received awarded grants. However, other characteristics determine a successful transition of the postdoctoral candidate into a research leader. These determinants are Identity, Independence and Image, Implementation ability in terms of being able to implement decisions and projects, working with Innovative and Important topics, having In-depth knowledge of the research topic, being Interactive and Integrated with the scientific community, and Internationally oriented. In conclusion, regardless of the framework of research, the

  1. Soybean GmPHD-Type Transcription Regulators Improve Stress Tolerance in Transgenic Arabidopsis Plants

    OpenAIRE

    Wei Wei; Jian Huang; Yu-Jun Hao; Hong-Feng Zou; Hui-Wen Wang; Jing-Yun Zhao; Xue-Yi Liu; Wan-Ke Zhang; Biao Ma; Jin-Song Zhang; Shou-Yi Chen

    2009-01-01

    BACKGROUND: Soybean [Glycine max (L.) Merr.] is one of the most important crops for oil and protein resource. Improvement of stress tolerance will be beneficial for soybean seed production. PRINCIPAL FINDINGS: Six GmPHD genes encoding Alfin1-type PHD finger protein were identified and their expressions differentially responded to drought, salt, cold and ABA treatments. The six GmPHDs were nuclear proteins and showed ability to bind the cis-element "GTGGAG". The N-terminal domain of GmPHD play...

  2. Three-zone pupil filters

    Science.gov (United States)

    Sheppard, Colin J. R.; Campos, Juan; Escalera, Juan C.; Ledesma, Silvia

    2008-07-01

    The performance of pupil filters consisting of three zones each of constant complex amplitude transmittance is investigated. For filters where the transmittance is real, different classes of potentially useful filter are identified. These include leaky filters with an inner zone of low amplitude transmittance, pure phase filters with phase change of π, and equal area filters.

  3. Adaptive Linear Filtering Design with Minimum Symbol Error Probability Criterion

    Institute of Scientific and Technical Information of China (English)

    Sheng Chen

    2006-01-01

    Adaptive digital filtering has traditionally been developed based on the minimum mean square error (MMSE)criterion and has found ever-increasing applications in communications. This paper presents an alternative adaptive filtering design based on the minimum symbol error rate (MSER) criterion for communication applications. It is shown that the MSER filtering is smarter, as it exploits the non-Gaussian distribution of filter output effectively. Consequently, it provides significant performance gain in terms of smaller symbol error over the MMSE approach. Adopting Parzen window or kernel density estimation for a probability density function, a block-data gradient adaptive MSER algorithm is derived. A stochastic gradient adaptive MSER algorithm, referred to as the least symbol error rate, is further developed for sampleby-sample adaptive implementation of the MSER filtering. Two applications, involving single-user channel equalization and beamforming assisted receiver, are included to demonstrate the effectiveness and generality of the proposed adaptive MSER filtering approach.

  4. The Virtual Observatory Powered PhD Thesis

    Science.gov (United States)

    Zolotukhin, I. Yu.

    2010-12-01

    The Virtual Observatory has reached sufficient maturity for its routine scientific exploitation by astronomers. To prove this statement, here I present a brief description of the complete VO-powered PhD thesis entitled “Galactic and extragalactic research with modern surveys and the Virtual Observatory” comprising 4 science cases covering various aspects of astrophysical research. These comprize: (1) homogeneous search and measurement of main physical parameters of Galactic open star clusters in huge multi-band photometric surveys; (2) study of optical-to-NIR galaxy colors using a large homogeneous dataset including spectroscopy and photometry from SDSS and UKIDSS; (3) study of faint low-mass X-ray binary population in modern observational archives; (4) search for optical counterparts of unidentified X-ray objects with large positional uncertainties in the Galactic Plane. All these projects make heavy use of the VO technologies and tools and would not be achievable without them. So refereed papers published in the frame of this thesis can undoubtedly be added to the growing list of VO-based research works.

  5. The JIM interview. Art Levinson, PhD.

    Science.gov (United States)

    Levinson, A

    1997-06-01

    In the early 1980s several prominent scientists left the hallowed halls of respected universities seeking to exploit the revolution occurring in biology in an environment devoid of the bureaucratic and political confines of academia. The emergence of the biotechnology industry has been marked by both spectacular failures and success stories. Genentech was founded in 1976 by biochemist Herbert Boyer and venture capitalist Robert Swanson and went public in 1980. In 1995 Genentech merged with Roche Holdings Ltd., of Basel Switzerland. Distinguished from other biotech companies by the varied array of products it has brought to market, Genentech has also developed a unique corporate culture embodying many traditional academic values. Just as Genentech went public in 1980, Arthur D. Levinson, PhD, finished a post-doctoral appointment in Michael Bishop's lab at the University of California, San Francisco. Despite the disapproval of colleagues, he joined the fledgling company as a senior scientist. Working his way though the ranks, Levinson became Vice President of Research Technology in 1989 and was named President and CEO in 1995. Interviewed at the sprawling corporate headquarters in South San Francisco, Levinson reflected on the process of high risk science, the benefits of the private sector, and the changing relationship between biotech companies and the academic world.

  6. Generic Kalman Filter Software

    Science.gov (United States)

    Lisano, Michael E., II; Crues, Edwin Z.

    2005-01-01

    The Generic Kalman Filter (GKF) software provides a standard basis for the development of application-specific Kalman-filter programs. Historically, Kalman filters have been implemented by customized programs that must be written, coded, and debugged anew for each unique application, then tested and tuned with simulated or actual measurement data. Total development times for typical Kalman-filter application programs have ranged from months to weeks. The GKF software can simplify the development process and reduce the development time by eliminating the need to re-create the fundamental implementation of the Kalman filter for each new application. The GKF software is written in the ANSI C programming language. It contains a generic Kalman-filter-development directory that, in turn, contains a code for a generic Kalman filter function; more specifically, it contains a generically designed and generically coded implementation of linear, linearized, and extended Kalman filtering algorithms, including algorithms for state- and covariance-update and -propagation functions. The mathematical theory that underlies the algorithms is well known and has been reported extensively in the open technical literature. Also contained in the directory are a header file that defines generic Kalman-filter data structures and prototype functions and template versions of application-specific subfunction and calling navigation/estimation routine code and headers. Once the user has provided a calling routine and the required application-specific subfunctions, the application-specific Kalman-filter software can be compiled and executed immediately. During execution, the generic Kalman-filter function is called from a higher-level navigation or estimation routine that preprocesses measurement data and post-processes output data. The generic Kalman-filter function uses the aforementioned data structures and five implementation- specific subfunctions, which have been developed by the user on

  7. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  8. Crux vena cava filter.

    Science.gov (United States)

    Murphy, Erin H; Johnson, Eric D; Kopchok, George E; Fogarty, Thomas J; Arko, Frank R

    2009-09-01

    Inferior vena cava filters are widely accepted for pulmonary embolic prophylaxis in high-risk patients with contraindications to anticoagulation. While long-term complications have been associated with permanent filters, retrievable filters are now available and have resulted in the rapid expansion of this technology. Nonetheless, complications are still reported with optional filters. Furthermore, device tilting and thrombus load may prevent retrieval in up to 30% of patients, thereby eliminating the benefits of this technology. The Crux vena cava filter is a novel, self-centering, low-profile filter that is designed for ease of delivery, retrievability and improved efficacy while limiting fatigue-related device complications. This device has been proven safe and user-friendly in an ovine model and has recently been implanted in human subjects.

  9. CrowdFilter

    DEFF Research Database (Denmark)

    Mortensen, Michael Lind; Wallace, Byron C.; Kraska, Tim

    for complex multi-criteria search problems through crowdsourcing. The CrowdFilter system is capable of supporting both criteria-level labels and n-gram rationales, capturing the human decision making process behind each filtering choice. Using the data provided through CrowdFilter we also introduce a novel......Multi-criteria filtering of mixed open/closed-world data is a time-consuming task, requiring significant manual effort when latent open-world attributes are present. In this work we introduce a novel open-world filtering framework CrowdFilter, enabling automatic UI generation and label elicitation...... multi-criteria active learning method; capable of incorporating labels and n-gram rationales per inclusion criteria, and thus capable of determining both clear includes/excludes, as well as complex borderline cases. By incorporating the active learning approach into the elicitation process of Crowd...

  10. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  11. Topology optimization of microwave waveguide filters

    DEFF Research Database (Denmark)

    Aage, Niels; Johansen, Villads Egede

    2017-01-01

    We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap optimizat......We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap...... little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering....

  12. Role of PHD fingers and COOH-terminal 30 amino acids in AIRE transactivation activity.

    Science.gov (United States)

    Meloni, Alessandra; Incani, Federica; Corda, Denise; Cao, Antonio; Rosatelli, Maria Cristina

    2008-02-01

    Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomic autoimmune disease resulting from the defective function of a gene codifying for a transcription factor named autoimmune regulation (AIRE). The AIRE protein contains several domains among which two PHD fingers involved in the transcriptional activation. We investigated the function of the two PHD finger domains and the COOH terminal portion of AIRE by using several mutated constructs transfected in mammalian cells and a luciferase reporter assay. The results predict that the second PHD as well as the COOH terminal regions have marked transactivational properties. The COOH terminal region contains the fourth LXXLL and the PXXPXP motifs which play a critical role in mediating the transactivation capacity of the AIRE protein. Our study provides a definition of the role of the PHD fingers in transactivation and identifies a new transactivation domain of the AIRE protein localized in the COOH terminal region.

  13. Actualization of the PhD Students' Intercultural Research Competencies in Global Society

    Directory of Open Access Journals (Sweden)

    Inga Dailidiene

    2013-12-01

    Full Text Available globalization is changing the qualitative characteristics of society, affecting both the life and mentality of people. In relevance to globalization, higher education is gaining new dimensions as well. Bologna and Lisbon documents guide and obligate each country to create integrated and harmonious international space of higher education in Europe. phd studies are considered as integral in the higher education structure; therefore, internationalization is a significant imperative for phd studies development. In the process of internationalization, the need for students’ intercultural competencies is widely recognized. Firstly, we suppose that the impact of globalization on internationalization still remains underestimated. Globalization makes internationalization not only more intense, but also qualitatively different. Secondly, there is a lack of systemic analysis on the development of intercultural research competencies in phd studies. We relate the need for intercultural research competencies to the following critical and rhetorical question: ‘Are today’s phd students ready to solve tomorrow’s global problems?’

  14. A New Venture in Graduate Education: Co-Op Ph.D. Programme in Chemical Engineering.

    Science.gov (United States)

    Fahidy, Thomas Z.

    1980-01-01

    Describes a cooperative Ph.D. program at the University of Waterloo, Ontario, Canada, in which industrial and governmental employers participate with the Department of Chemical Engineering in training chemical engineers. (CS)

  15. Doc of prophage P1 is inhibited by its antitoxin partner Phd through fold complementation

    DEFF Research Database (Denmark)

    Garcia-Pino, Abel; Christensen-Dalsgaard, Mikkel; Wyns, Lode

    2008-01-01

    evolutionary origin for the phd/doc operon. Doc induces growth arrest of Escherichia coli cells in a reversible manner, by targeting the protein synthesis machinery. Moreover, Doc activates the endogenous E. coli RelE mRNA interferase but does not require this or any other known chromosomal toxin......Prokaryotic toxin-antitoxin modules are involved in major physiological events set in motion under stress conditions. The toxin Doc (death on curing) from the phd/doc module on phage P1 hosts the C-terminal domain of its antitoxin partner Phd (prevents host death) through fold complementation....... This Phd domain is intrinsically disordered in solution and folds into an alpha-helix upon binding to Doc. The details of the interactions reveal the molecular basis for the inhibitory action of the antitoxin. The complex resembles the Fic (filamentation induced by cAMP) proteins and suggests a possible...

  16. PhD Wang Xingchu,A Successful Leader of A High-tech Company Reform

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ PhD Wang Xingchu was born in 1962. He is the Board Chairman of Shanghai Biotechnology Industrial Garden Coalition Development Co., Ltd. and the General Manager of Shanghai Hua Xin High-Biotechnology Co., Ltd.

  17. Trends in landscape research and landscape planning : implications for PhD students

    NARCIS (Netherlands)

    Tress, G.; Tress, B.; Fry, G.; Antrop, M.

    2005-01-01

    This chapter introduces the contents of the book through an analysis of current trends in landscape research and landscape planning and a discussion of the consequences of these trends for PhD students.

  18. Optimization-based particle filter for state and parameter estimation

    Institute of Scientific and Technical Information of China (English)

    Li Fu; Qi Fei; Shi Guangming; Zhang Li

    2009-01-01

    In recent years, the theory of particle filter has been developed and widely used for state and parameter estimation in nonlinear/non-Gaussian systems. Choosing good importance density is a critical issue in particle filter design. In order to improve the approximation of posterior distribution, this paper provides an optimization-based algorithm (the steepest descent method) to generate the proposal distribution and then sample particles from the distribution. This algorithm is applied in 1-D case, and the simulation results show that the proposed particle filter performs better than the extended Kalman filter (EKF), the standard particle filter (PF), the extended Kalman particle filter (PF-EKF) and the unscented particle filter (UPF) both in efficiency and in estimation precision.

  19. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  20. Articulating Expectations for PhD Candidature upon Commencement: Ensuring Supervisor/Student "Best Fit"

    Science.gov (United States)

    Moxham, Lorna; Dwyer, Trudy; Reid-Searl, Kerry

    2013-01-01

    The journey towards completion of a PhD is a bumpy one for many. One of the major factors that influence successful and on-time thesis completion is the relationship that the PhD candidate has with her or his supervisor. This paper presents results from research undertaken using a 12-item survey to collect data from a purposive sample: PhD…

  1. Oriented Fiber Filter Media

    Directory of Open Access Journals (Sweden)

    R. Bharadwaj

    2008-06-01

    Full Text Available Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a thick layered media can improve performance by about 40%. The results also show the improved performance is not monotonically correlated to the average fiber angle of the medium.

  2. Fundamentals of Stochastic Filtering

    CERN Document Server

    Crisan, Dan

    2008-01-01

    The objective of stochastic filtering is to determine the best estimate for the state of a stochastic dynamical system from partial observations. The solution of this problem in the linear case is the well known Kalman-Bucy filter which has found widespread practical application. The purpose of this book is to provide a rigorous mathematical treatment of the non-linear stochastic filtering problem using modern methods. Particular emphasis is placed on the theoretical analysis of numerical methods for the solution of the filtering problem via particle methods. The book should provide sufficient

  3. Skill development in collaborative research projects: A comparison between PhD students in multi-actor research programs and in traditional trajectories

    NARCIS (Netherlands)

    Wardenaar, T.; Belder, R.; de Goede, M.E.E; Horlings, E.; van den Besselaar, P.

    2014-01-01

    The growing number of PhD students has spurred debates about the societal relevance of PhD training trajectories. The academic labour market does not provide enough jobs and many PhD graduates will have a career outside academia. It has been questioned whether current PhD training trajectories are s

  4. Skill development in collaborative research projects: A comparison between PhD students in multi-actor research programs and in traditional trajectories

    NARCIS (Netherlands)

    Wardenaar, T.; Belder, R.; de Goede, M.E.E; Horlings, E.; van den Besselaar, P.

    2014-01-01

    The growing number of PhD students has spurred debates about the societal relevance of PhD training trajectories. The academic labour market does not provide enough jobs and many PhD graduates will have a career outside academia. It has been questioned whether current PhD training trajectories are s

  5. MS PHD'S: Effective Strategies for the Retention and Advancement of URM Students in ESS

    Science.gov (United States)

    Escalera, J.; Burgess, A. K.; Pace, L.; Scott, O.; Strickland, J.; Johnson, A.; Williamson Whitney, V.; Ithier-Guzman, W.

    2012-12-01

    The Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S) Professional Development Program in Earth system science (ESS) is a model initiative for improving the retention of underrepresented minority (URM) students in STEM fields. Entering its ninth cohort, MS PHD'S remains committed to helping URM undergraduate and graduate students achieve outstanding careers in ESS. MS PHD'S facilitates URM student achievement through a three-phase program designed to increase student exposure to the ESS community. By engaging in a series of professional development and skill building exercises, peer-to-peer community building activities, participation in scientific society conferences and workshops, mentoring by URM and other scientists, and a virtual community, URM students gain the confidence and support necessary to achieve their academic goals and enter the ESS workforce. Since its inception, MS PHD'S continues to support 189 participants. Of these 189 participants, 35 have advanced from undergraduate and graduate academic pathways to completion of their PhD and another 60 are currently enrolled in doctoral programs. MS PHD'S maintains close ties with program alumni to further support retention, inclusivity, and broadening participation of URM students and graduates in STEM activities. Its model is built on reengaging alumni to become mentors and leaders for each new cohort as well as facilitating valuable opportunities for alumni to advance in their ESS related academic and professional career pathways.

  6. Structure of human Sp140 PHD finger: an atypical fold interacting with Pin1.

    Science.gov (United States)

    Zucchelli, Chiara; Tamburri, Simone; Quilici, Giacomo; Palagano, Eleonora; Berardi, Andrea; Saare, Mario; Peterson, Pärt; Bachi, Angela; Musco, Giovanna

    2014-01-01

    Sp140 is a nuclear leukocyte-specific protein involved in primary biliary cirrhosis and a risk factor in chronic lymphocytic leukemia. The presence of several chromatin related modules such as plant homeodomain (PHD), bromodomain and SAND domain suggests a role in chromatin-mediated regulation of gene expression; however, its real function is still elusive. Herein we present the solution structure of Sp140-PHD finger and investigate its role as epigenetic reader in vitro. Sp140-PHD presents an atypical PHD finger fold which does not bind to histone H3 tails but is recognized by peptidylprolyl isomerase Pin1. Pin1 specifically binds to a phosphopeptide corresponding to the L3 loop of Sp140-PHD and catalyzes cis-trans isomerization of a pThr-Pro bond. Moreover co-immunoprecipitation experiments demonstrate FLAG-Sp140 interaction with endogenous Pin1 in vivo. Overall these data include Sp140 in the list of the increasing number of Pin1 binders and expand the regulatory potential of PHD fingers as versatile structural platforms for diversified interactions. © 2013 FEBS.

  7. Solution NMR structure and histone binding of the PHD domain of human MLL5.

    Directory of Open Access Journals (Sweden)

    Alexander Lemak

    Full Text Available Mixed Lineage Leukemia 5 (MLL5 is a histone methyltransferase that plays a key role in hematopoiesis, spermatogenesis and cell cycle progression. In addition to its catalytic domain, MLL5 contains a PHD finger domain, a protein module that is often involved in binding to the N-terminus of histone H3. Here we report the NMR solution structure of the MLL5 PHD domain showing a variant of the canonical PHD fold that combines conserved H3 binding features from several classes of other PHD domains (including an aromatic cage along with a novel C-terminal α-helix, not previously seen. We further demonstrate that the PHD domain binds with similar affinity to histone H3 tail peptides di- and tri-methylated at lysine 4 (H3K4me2 and H3K4me3, the former being the putative product of the MLL5 catalytic reaction. This work establishes the PHD domain of MLL5 as a bone fide 'reader' domain of H3K4 methyl marks suggesting that it may guide the spreading or further methylation of this site on chromatin.

  8. Filter holder and gasket assembly for candle or tube filters

    Science.gov (United States)

    Lippert, Thomas Edwin; Alvin, Mary Anne; Bruck, Gerald Joseph; Smeltzer, Eugene E.

    1999-03-02

    A filter holder and gasket assembly for holding a candle filter element within a hot gas cleanup system pressure vessel. The filter holder and gasket assembly includes a filter housing, an annular spacer ring securely attached within the filter housing, a gasket sock, a top gasket, a middle gasket and a cast nut.

  9. Inhibition of the oxygen sensor PHD2 in the liver improves survival in lactic acidosis by activating the Cori cycle.

    Science.gov (United States)

    Suhara, Tomohiro; Hishiki, Takako; Kasahara, Masataka; Hayakawa, Noriyo; Oyaizu, Tomoko; Nakanishi, Tsuyoshi; Kubo, Akiko; Morisaki, Hiroshi; Kaelin, William G; Suematsu, Makoto; Minamishima, Yoji Andrew

    2015-09-15

    Loss of prolyl hydroxylase 2 (PHD2) activates the hypoxia-inducible factor-dependent hypoxic response, including anaerobic glycolysis, which causes large amounts of lactate to be released from cells into the circulation. We found that Phd2-null mouse embryonic fibroblasts (MEFs) produced more lactate than wild-type MEFs, as expected, whereas systemic inactivation of PHD2 in mice did not cause hyperlacticacidemia. This unexpected observation led us to hypothesize that the hypoxic response activated in the liver enhances the Cori cycle, a lactate-glucose carbon recycling system between muscle and liver, and thereby decreases circulating lactate. Consistent with this hypothesis, blood lactate levels measured after a treadmill or lactate tolerance test were significantly lower in Phd2-liver-specific knockout (Phd2-LKO) mice than in control mice. An in vivo (13)C-labeled lactate incorporation assay revealed that the livers of Phd2-LKO mice produce significantly more glucose derived from (13)C-labeled lactate than control mice, suggesting that blockade of PHD2 in the liver ameliorates lactic acidosis by activating gluconeogenesis from lactate. Phd2-LKO mice were resistant to lactic acidosis induced by injection of a lethal dose of lactate, displaying a significant elongation of survival. Moreover, oral administration of a PHD inhibitor improved survival in an endotoxin shock mice model. These data suggest that PHD2 is a potentially novel drug target for the treatment of lactic acidosis, which is a serious and often fatal complication observed in some critically ill patients.

  10. Fast Anisotropic Gauss Filtering

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.; Heyden, A.; Sparr, G.; Nielsen, M.; Johansen, P.

    2002-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction followed by a one dimensional filter in a non-orthogonal direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computin

  11. Multilevel ensemble Kalman filter

    KAUST Repository

    Chernov, Alexey

    2016-01-06

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF). In terms of computational cost vs. approximation error the asymptotic performance of the multilevel ensemble Kalman filter (MLEnKF) is superior to the EnKF s.

  12. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Wells, George; Beaton, Dorcas E; Tugwell, Peter;

    2014-01-01

    The "Discrimination" part of the OMERACT Filter asks whether a measure discriminates between situations that are of interest. "Feasibility" in the OMERACT Filter encompasses the practical considerations of using an instrument, including its ease of use, time to complete, monetary costs, and inter...

  13. From Doctoral Student To Faculty Member: PhD. Project Alumni’s Evaluation Of Their Preparedness

    Directory of Open Access Journals (Sweden)

    Bill N. Schwartz

    2012-03-01

    Full Text Available In response to the important issues regarding diversity in business schools and corporate America, the KPMG Foundation established the PhD Project. The PhD Project helps business professionals and recent college graduates earn doctoral degrees in business disciplines and join business school faculty. While the PhD Project has helped increase the number of minority faculty members in business schools, it may be helpful to gather insights from the recent PhD alumni who have received support from the PhD Project. Our study examines attitudes about preparedness of PhD Project alums for their first faculty position after completing their PhD program. Results show that PhD Project alumni and majority PhD alumni (alumni not associated with the PhD Project felt they were prepared for their first faculty position, but they were not significantly different in their evaluation in most respects. However, to our surprise, majority PhD alumni felt they were better prepared for research than PhD Project alumni. This difference was significant and further analyses showed that younger faculty and those in the ethnic majority were better prepared for research. Both groups considered themselves well prepared for research and teaching. Neither group was as optimistic about being prepared for service responsibilities and the academic climate or politics of an academic career. Our findings show that the PhD Project is necessary to help ensure that minority faculty members are adequately prepared for research and their academic careers.

  14. Vena cava filter; Vena-cava-Filter

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, T. [Klinikum Bogenhausen, Institut fuer Diagnostische und Interventionelle Radiologie und Nuklearmedizin, Muenchen (Germany)

    2007-05-15

    Fulminant pulmonary embolism is one of the major causes of death in the Western World. In most cases, deep leg and pelvic venous thrombosis are the cause. If an anticoagulant/thrombotic therapy is no longer possible or ineffective, a vena cava filter implant may be indicated if an embolism is threatening. Implantation of the filter is a simple and safe intervention. Nevertheless, it is necessary to take into consideration that the data base for determining the indications for this treatment are very limited. Currently, a reduction in the risk of thromboembolism with the use of filters of about 30%, of recurrences of almost 5% and fatal pulmonary embolism of 1% has been reported, with a risk of up to 20% of filter induced vena cava thrombosis. (orig.) [German] Die fulminante Lungenembolie zaehlt zu den Haupttodesursachen in der westlichen Welt. In der Mehrzahl der Faelle sind tiefe Bein- und Beckenvenenthrombosen ursaechlich verantwortlich. Ist eine antikoagulative/-thrombotische Therapie nicht (mehr) moeglich oder unwirksam, kann bei drohender Emboliegefahr die Vena-cava-Filterimplantation indiziert sein. Die Filterimplantation ist eine einfache und sehr sichere Intervention. Dennoch muss bei der Indikationsstellung beruecksichtigt werden, dass die Datenlage zur Wirksamkeit sehr limitiert ist. So wird aktuell ueber eine Reduktion des Thrombembolierisikos um 30% bei Embolierezidiven von knapp 5% und fatalen Lungenembolien von 1% unter Filterprophylaxe berichtet, bei einem Risiko von bis zu 20% fuer die filterinduzierte Vena-cava-Thrombose. (orig.)

  15. Preparing for Graduate-Level Training in Professional Psychology: Comparisons across Clinical PhD, Counseling PhD, and Clinical PsyD Programs

    Science.gov (United States)

    Karazsia, Bryan T.; Smith, Lena

    2016-01-01

    In the present study, faculty who teach in clinical and counseling doctor of philosophy (PhD) or doctor of psychology (PsyD) programs completed surveys regarding preferences for prospective student preparations to graduate programs. Faculty expectations of minimum and ideal undergraduate training were highest for scientific methods, though…

  16. Preparing for Graduate-Level Training in Professional Psychology: Comparisons across Clinical PhD, Counseling PhD, and Clinical PsyD Programs

    Science.gov (United States)

    Karazsia, Bryan T.; Smith, Lena

    2016-01-01

    In the present study, faculty who teach in clinical and counseling doctor of philosophy (PhD) or doctor of psychology (PsyD) programs completed surveys regarding preferences for prospective student preparations to graduate programs. Faculty expectations of minimum and ideal undergraduate training were highest for scientific methods, though…

  17. Professional Socialization for the Ph.D.: An Exploration of Career and Professional Development Preparedness and Readiness for Ph.D. Candidates

    Science.gov (United States)

    Helm, Matt; Campa, Henry, III; Moretto, Kristin

    2012-01-01

    This study sought to uncover the career readiness and professional development needs of Ph.D. students at a large, Midwestern research university. Findings indicate that career goals of graduate students change over time, skill preparation for academic and non-academic careers continues to be inadequate for many students and professional…

  18. Weighted guided image filtering.

    Science.gov (United States)

    Li, Zhengguo; Zheng, Jinghong; Zhu, Zijian; Yao, Wei; Wu, Shiqian

    2015-01-01

    It is known that local filtering-based edge preserving smoothing techniques suffer from halo artifacts. In this paper, a weighted guided image filter (WGIF) is introduced by incorporating an edge-aware weighting into an existing guided image filter (GIF) to address the problem. The WGIF inherits advantages of both global and local smoothing filters in the sense that: 1) the complexity of the WGIF is O(N) for an image with N pixels, which is same as the GIF and 2) the WGIF can avoid halo artifacts like the existing global smoothing filters. The WGIF is applied for single image detail enhancement, single image haze removal, and fusion of differently exposed images. Experimental results show that the resultant algorithms produce images with better visual quality and at the same time halo artifacts can be reduced/avoided from appearing in the final images with negligible increment on running times.

  19. Robustifying Vector Median Filter

    Directory of Open Access Journals (Sweden)

    Valentín Gregori

    2011-08-01

    Full Text Available This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view. Both methods work by determining first the vector median in a given filtering window. Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components. The correlation among the colour channels is taken into account in the processing and, as a result, a more robust filter able to process colour images without introducing colour artifacts is obtained. Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter. Objective measures demonstrate the goodness of the achieved improvement.

  20. Filter cake breaker systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo H.F. [Poland Quimica Ltda., Duque de Caxias, RJ (Brazil)

    2004-07-01

    Drilling fluids filter cakes are based on a combination of properly graded dispersed particles and polysaccharide polymers. High efficiency filter cakes are formed by these combination , and their formation on wellbore walls during the drilling process has, among other roles, the task of protecting the formation from instantaneous or accumulative invasion of drilling fluid filtrate, granting stability to well and production zones. Filter cake minimizes contact between drilling fluid filtrate and water, hydrocarbons and clay existent in formations. The uniform removal of the filter cake from the entire interval is a critical factor of the completion process. The main methods used to breaking filter cake are classified into two groups, external or internal, according to their removal mechanism. The aim of this work is the presentation of these mechanisms as well their efficiency. (author)

  1. Naive Bayesian for Email Filtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper presents a method of email filter based on Naive Bayesian theory that can effectively filter junk mail and illegal mail. Furthermore, the keys of implementation are discussed in detail. The filtering model is obtained from training set of email. The filtering can be done without the users specification of filtering rules.

  2. Marker-Less Stage Drift Correction in Super-Resolution Microscopy Using the Single-Cluster PHD Filter

    NARCIS (Netherlands)

    Schlangen, I. (Isabel); Franco, J. (José); Houssineau, J. (Jérémie); Pitkeathly, W.T.E. (William T.E.); Clark, D. (Daniel); I. Smal (Ihor); Rickman, C. (Colin)

    2016-01-01

    textabstractFluorescence microscopy is a technique which allows the imaging of cellular and intracellular dynamics through the activation of fluorescent molecules attached to them. It is a very important technique because it can be used to analyze the behavior of intracellular processes in vivo in c

  3. A PHD-polycomb repressive complex 2 triggers the epigenetic silencing of FLC during vernalization.

    Science.gov (United States)

    De Lucia, Filomena; Crevillen, Pedro; Jones, Alexandra M E; Greb, Thomas; Dean, Caroline

    2008-11-04

    Vernalization, the acceleration of flowering by winter, involves cold-induced epigenetic silencing of Arabidopsis FLC. This process has been shown to require conserved Polycomb Repressive Complex 2 (PRC2) components including the Su(z)12 homologue, VRN2, and two plant homeodomain (PHD) finger proteins, VRN5 and VIN3. However, the sequence of events leading to FLC repression was unclear. Here we show that, contrary to expectations, VRN2 associates throughout the FLC locus independently of cold. The vernalization-induced silencing is triggered by the cold-dependent association of the PHD finger protein VRN5 to a specific domain in FLC intron 1, and this association is dependent on the cold-induced PHD protein VIN3. In plants returned to warm conditions, VRN5 distribution changes, and it associates more broadly over FLC, coincident with significant increases in H3K27me3. Biochemical purification of a VRN5 complex showed that during prolonged cold a PHD-PRC2 complex forms composed of core PRC2 components (VRN2, SWINGER [an E(Z) HMTase homologue], FIE [an ESC homologue], MSI1 [p55 homologue]), and three related PHD finger proteins, VRN5, VIN3, and VEL1. The PHD-PRC2 activity increases H3K27me3 throughout the locus to levels sufficient for stable silencing. Arabidopsis PHD-PRC2 thus seems to act similarly to Pcl-PRC2 of Drosophila and PHF1-PRC2 of mammals. These data show FLC silencing involves changed composition and dynamic redistribution of Polycomb complexes at different stages of the vernalization process, a mechanism with greater parallels to Polycomb silencing of certain mammalian loci than the classic Drosophila Polycomb targets.

  4. Development and applications of ionospheric tomography. Ph.D. Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Raymund, T.D.

    1993-12-31

    Recently, several tomographic techniques for ionospheric electron density imaging have been proposed. These techniques reconstruct a vertical slice image of electron density using total electron content data. The data are measured between a low orbit beacon satellite and fixed receivers located along the projected orbital path of the satellite. By using such tomographic techniques, it may be possible to inexpensively (relative to incoherent scatter techniques) image the ionospheric electron density in a vertical plane several times per day. The satellite and receiver geometry used to measure the total electron content data causes the data to be incomplete; that is, the measured data do not contain enough information to completely specify the ionospheric electron density distribution in the region between the satellite and the receivers. A new algorithm is proposed which allows the incorporation of other complementary measurements, such as those from ionosondes, and also includes ways to include a priori information about the unknown electron density distribution in the reconstruction process. The algorithm makes use of two-dimensional basis functions. Illustrative application of this algorithm is made to simulated cases with good results. The technique is also applied to real total electron content (TEC) records collected in Scandinavia in conjunction with the EISCAT incoherent scatter radar. The tomographic reconstructions are compared with the incoherent scatter electron density images of the same region of the ionosphere.

  5. Derivative free filtering using Kalmtool

    DEFF Research Database (Denmark)

    Bayramoglu, Enis; Hansen, Søren; Ravn, Ole;

    2010-01-01

    In this paper we present a toolbox enabling easy evaluation and comparison of different filtering algorithms. The toolbox is called Kalmtool 4 and is a set of MATLAB tools for state estimation of nonlinear systems. The toolbox contains functions for extended Kalman filtering as well as for DD1...... filter and the DD2 filter. It also contains functions for Unscented Kalman filters as well as several versions of particle filters. The toolbox requires MATLAB version 7, but no additional toolboxes are required....

  6. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  7. EMI filter design

    CERN Document Server

    Ozenbaugh, Richard Lee

    2011-01-01

    With today's electrical and electronics systems requiring increased levels of performance and reliability, the design of robust EMI filters plays a critical role in EMC compliance. Using a mix of practical methods and theoretical analysis, EMI Filter Design, Third Edition presents both a hands-on and academic approach to the design of EMI filters and the selection of components values. The design approaches covered include matrix methods using table data and the use of Fourier analysis, Laplace transforms, and transfer function realization of LC structures. This edition has been fully revised

  8. Randomized Filtering Algorithms

    DEFF Research Database (Denmark)

    Katriel, Irit; Van Hentenryck, Pascal

    2008-01-01

    of AllDifferent and is generalization, the Global Cardinality Constraint. The first delayed filtering scheme is a Monte Carlo algorithm: its running time is superior, in the worst case, to that of enforcing are consistency after every domain event, while its filtering effectiveness is analyzed...... in the expected sense. The second scheme is a Las Vegas algorithm using filtering triggers: Its effectiveness is the same as enforcing are consistency after every domain event, while in the expected case it is faster by a factor of m/n, where n and m are, respectively, the number of nodes and edges...

  9. Air Filter Simulation by Geodict

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-peng; Kitai Kim; Changhwan Lee; Jooyong Kim

    2006-01-01

    In this paper, we discussed the relationship of filter efficiency and pressure drop with the porosity, fiber diameter and filter thickness by Geodict. We found that filter efficiency will increase when filter porosity and fiber diameter decreasing or filter thickness increasing. And the pressure drop has a linear relationship with filter thickness and non-linear relationship with filter porosity and fiber diameter. We also compared the simulation results with the real test results by TSI 3160. Although there are some differences, I think Geodict can be used to predict filter efficiency and pressure drop.

  10. PhD students’ expectations from their supervisors: A qualitative content analysis

    Directory of Open Access Journals (Sweden)

    SH Rimaz

    2015-03-01

    Full Text Available Introduction: Quality of research in PhD programs increases if supervisors become aware of students' expectations from them. This qualitative study aimed to explore expectations of PhD students from their supervisors was done.   Methods: This qualitative content analysis study was conducted on 22 graduated PhD students of Iran University of Medical Sciences, in 2014. The samples were purposefully selected and interviewed. All interviews were recorded and transcribed verbatim.   Results: After analyzing and coding data, it was found that PhD students have four main expectations from their supervisors. These expectations consist of scientific support including help with selection of subject, preparation and registration of proposal, data collection and support for writing and examination of the thesis. Developing scientific skills and help with preparing manuscripts were other expectations. Emotional-social support with five categories including relationship between supervisor-student, general expectations of supervisor, supervisor personality characteristics, needed emotional skills and social activities related to thesis and finally providing adequate resources including financial support and access to facilities inside and outside the university were among the other expectations.   Conclusion: PhD students need to scientific, emotional, social and material supports from their supervisors in the process of performing thesis. These expectations should be told to supervisors.

  11. Predicting the "graduate on time (GOT)" of PhD students using binary logistics regression model

    Science.gov (United States)

    Shariff, S. Sarifah Radiah; Rodzi, Nur Atiqah Mohd; Rahman, Kahartini Abdul; Zahari, Siti Meriam; Deni, Sayang Mohd

    2016-10-01

    Malaysian government has recently set a new goal to produce 60,000 Malaysian PhD holders by the year 2023. As a Malaysia's largest institution of higher learning in terms of size and population which offers more than 500 academic programmes in a conducive and vibrant environment, UiTM has taken several initiatives to fill up the gap. Strategies to increase the numbers of graduates with PhD are a process that is challenging. In many occasions, many have already identified that the struggle to get into the target set is even more daunting, and that implementation is far too ideal. This has further being progressing slowly as the attrition rate increases. This study aims to apply the proposed models that incorporates several factors in predicting the number PhD students that will complete their PhD studies on time. Binary Logistic Regression model is proposed and used on the set of data to determine the number. The results show that only 6.8% of the 2014 PhD students are predicted to graduate on time and the results are compared wih the actual number for validation purpose.

  12. MS PHD'S: A Synergistic Model for Diversifying the Earth Science Community

    Science.gov (United States)

    Ricciardi, L.; Johnson, A.; Williamson Whitney, V.; Ithier-Guzman, W.; Braxton, L.; Johnson, A.

    2013-05-01

    The Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S) program focuses on increasing the number of underrepresented minorities (URM) receiving advanced degrees in Earth system sciences (ESS). Subscribing to Aristotle's philosophy that the "whole is greater than the sum of its parts", MS PHD'S uses a synergistic model of tiered mentoring practices, successful minority scientist role models, peer-to-peer community building activities, professional development training techniques, networking opportunities, and state of the art virtual communication tools to facilitate the retention and advancement of underrepresented ESS scientists. Using a three-phase program structure supported by a virtual community, URM students in ESS are afforded opportunities to establish mentoring relationships with successful scientists, build meaningful ties with URM peers and future colleagues, strengthen oral and written communication skills, engage in networking opportunities within premier scientific venues, and maintain continuity of networks formed through program participation. Established in 2003, MS PHD'S is now in its ninth cohort. From the original cohort of 24 participants, the program has grown to support 213 participants. Of these 213 participants, 42 have obtained the doctorate and are employed within the ESS workforce. Another 71 are enrolled in doctoral programs. Looking to the future with the purpose of continually furthering its synergistic philosophy, MS PHD'S has developed a new initiative, Beyond the PhD, designed to support and advance the representation of URM scientists within a global workforce.

  13. Oxygen-dependent ATF-4 stability is mediated by the PHD3 oxygen sensor.

    Science.gov (United States)

    Köditz, Jens; Nesper, Jutta; Wottawa, Marieke; Stiehl, Daniel P; Camenisch, Gieri; Franke, Corinna; Myllyharju, Johanna; Wenger, Roland H; Katschinski, Dörthe M

    2007-11-15

    The activating transcription factor-4 (ATF-4) is translationally induced under anoxic conditions, mediates part of the unfolded protein response following endoplasmic reticulum (ER) stress, and is a critical regulator of cell fate. Here, we identified the zipper II domain of ATF-4 to interact with the oxygen sensor prolyl-4-hydroxylase domain 3 (PHD3). The PHD inhibitors dimethyloxalylglycine (DMOG) and hypoxia, or proteasomal inhibition, all induced ATF-4 protein levels. Hypoxic induction of ATF-4 was due to increased protein stability, but was independent of the ubiquitin ligase von Hippel-Lindau protein (pVHL). A novel oxygen-dependent degradation (ODD) domain was identified adjacent to the zipper II domain. Mutations of 5 prolyl residues within this ODD domain or siRNA-mediated down-regulation of PHD3, but not of PHD2, was sufficient to stabilize ATF-4 under normoxic conditions. These data demonstrate that PHD-dependent oxygen-sensing recruits both the hypoxia-inducible factor (HIF) and ATF-4 systems, and hence not only confers adaptive responses but also cell fate decisions.

  14. Interoperability in digital electrocardiography: harmonization of ISO/IEEE x73-PHD and SCP-ECG.

    Science.gov (United States)

    Trigo, Jesús D; Chiarugi, Franco; Alesanco, Alvaro; Martínez-Espronceda, Miguel; Serrano, Luis; Chronaki, Catherine E; Escayola, Javier; Martínez, Ignacio; García, José

    2010-11-01

    The ISO/IEEE 11073 (x73) family of standards is a reference frame for medical device interoperability. A draft for an ECG device specialization (ISO/IEEE 11073-10406-d02) has already been presented to the Personal Health Device (PHD) Working Group, and the Standard Communications Protocol for Computer-Assisted ElectroCardioGraphy (SCP-ECG) Standard for short-term diagnostic ECGs (EN1064:2005+A1:2007) has recently been approved as part of the x73 family (ISO 11073-91064:2009). These factors suggest the coordinated use of these two standards in foreseeable telecardiology environments, and hence the need to harmonize them. Such harmonization is the subject of this paper. Thus, a mapping of the mandatory attributes defined in the second draft of the ISO/IEEE 11073-10406-d02 and the minimum SCP-ECG fields is presented, and various other capabilities of the SCP-ECG Standard (such as the messaging part) are also analyzed from an x73-PHD point of view. As a result, this paper addresses and analyzes the implications of some inconsistencies in the coordinated use of these two standards. Finally, a proof-of-concept implementation of the draft x73-PHD ECG device specialization is presented, along with the conversion from x73-PHD to SCP-ECG. This paper, therefore, provides recommendations for future implementations of telecardiology systems that are compliant with both x73-PHD and SCP-ECG.

  15. Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

    Energy Technology Data Exchange (ETDEWEB)

    McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

    2006-01-01

    Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

  16. Anisotropic Density Estimation in Global Illumination

    DEFF Research Database (Denmark)

    Schjøth, Lars

    2009-01-01

    Density estimation employed in multi-pass global illumination algorithms gives cause to a trade-off problem between bias and noise. The problem is seen most evident as blurring of strong illumination features. This thesis addresses the problem, presenting four methods that reduce both noise...... and bias in estimates. Good results are obtained by the use of anisotropic filtering. Two methods handles the most common cases; filtering illumination reflected from object surfaces. One methods extends filtering to the temporal domain and one performs filtering on illumination from participating media...

  17. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Kirwan, John R; Boers, Maarten; Hewlett, Sarah

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes that are......OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes...... that are universal to all studies of the effects of intervention effects. There is no published outline for instrument choice or development that is aimed at measuring outcome, was derived from broad consensus over its underlying philosophy, or includes a structured and documented critique. Therefore, a new proposal...

  18. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    D'Agostino, Maria-Antonietta; Boers, Maarten; Kirwan, John

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imagin...

  19. Paul Rodgersi filter Kohilas

    Index Scriptorium Estoniae

    2000-01-01

    28. I Kohila keskkoolis kohaspetsiifiline skulptuur ja performance "Filter". Kooli 130. aastapäeva tähistava ettevõtmise eesotsas oli skulptor Paul Rodgers ja kaks viimase klassi noormeest ئ Marko Heinmäe, Hendrik Karm.

  20. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Tugwell, Peter; Boers, Maarten; D'Agostino, Maria-Antonietta

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter requires that criteria be met to demonstrate that the outcome instrument meets...... the criteria for content, face, and construct validity. METHODS: Discussion groups critically reviewed a variety of ways in which case studies of current OMERACT Working Groups complied with the Truth component of the Filter and what issues remained to be resolved. RESULTS: The case studies showed...... that there is broad agreement on criteria for meeting the Truth criteria through demonstration of content, face, and construct validity; however, several issues were identified that the Filter Working Group will need to address. CONCLUSION: These issues will require resolution to reach consensus on how Truth...

  1. Paul Rodgersi filter Kohilas

    Index Scriptorium Estoniae

    2000-01-01

    28. I Kohila keskkoolis kohaspetsiifiline skulptuur ja performance "Filter". Kooli 130. aastapäeva tähistava ettevõtmise eesotsas oli skulptor Paul Rodgers ja kaks viimase klassi noormeest ئ Marko Heinmäe, Hendrik Karm.

  2. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  3. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-07

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  4. Cryogenic coaxial microwave filters

    CERN Document Server

    Tancredi, G; Meeson, P J

    2014-01-01

    At millikelvin temperatures the careful filtering of electromagnetic radiation, especially in the microwave regime, is critical for controlling the electromagnetic environment for experiments in fields such as solid-state quantum information processing and quantum metrology. We present a design for a filter consisting of small diameter dissipative coaxial cables that is straightforward to construct and provides a quantitatively predictable attenuation spectrum. We describe the fabrication process and demonstrate that the performance of the filters is in good agreement with theoretical modelling. We further perform an indicative test of the performance of the filters by making current-voltage measurements of small, underdamped Josephson Junctions at 15 mK and we present the results.

  5. Holographic interference filters

    Science.gov (United States)

    Diehl, Damon W.

    Holographic mirrors have wavelength-selection properties and thus qualify as a class of interference filters. Two theoretical methods for analyzing such structures are developed. The first method uses Hill's matrix method to yield closed-forms solutions in terms of the Floquet-Bloch waves within a periodic structure. A process is developed for implementing this solution method on a computer, using sparse-matrix memory allocation, numerical root-finding algorithms, and inverse-iteration techniques. It is demonstrated that Hill's matrix method is valid for the analysis of finite and multi-periodic problems. The second method of theoretical analysis is a transfer-matrix technique, which is herein termed thin-film decomposition. It is shown that the two methods of solution yield results that differ by, at worst, a fraction of a percent. Using both calculation techniques, a number of example problems are explored. Of key importance is the construction of a set of curves that are useful for the design and characterization of holographic interference filters. In addition to the theoretical development, methods are presented for the fabrication of holographic interference filters using DuPont HRF-800X001 photopolymer. Central to the exposure system is a frequency-stabilized, tunable dye laser. The types of filters fabricated include single-tone reflection filters, two types of multitone reflection filters, and reflection filters for infrared wavelengths. These filters feature index profiles that are not easily attainable through other fabrication methods. As a supplement to the body of the dissertation, the computer algorithms developed to implement Hill's matrix method and thin-film decomposition are also included as an appendix. Further appendices provide more information on Floquet's theorem and Hill's matrix method. A final appendix presents a design for an infrared laser spectrophotometer.

  6. The Endogenous Kalman Filter

    OpenAIRE

    Brad Baxter; Liam Graham; Stephen Wright

    2007-01-01

    We relax the assumption of full information that underlies most dynamic general equilibrium models, and instead assume agents optimally form estimates of the states from an incomplete information set. We derive a version of the Kalman filter that is endogenous to agents' optimising decisions, and state conditions for its convergence. We show the (restrictive) conditions under which the endogenous Kalman filter will at least asymptotically reveal the true states. In general we show that incomp...

  7. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  8. Contactor/filter improvements

    Science.gov (United States)

    Stelman, David

    1989-01-01

    A contactor/filter arrangement for removing particulate contaminants from a gaseous stream includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. The housing further includes a gas inlet means, a gas outlet means, and means for moving a body of granular material through the zone. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. Disposed on the upstream face of the filter element is a cover screen which isolates the filter element from contact with the moving granular bed and collects a portion of the particulates so as to form a dust cake having openings small enough to exclude the granular material, yet large enough to receive the dust particles. In one embodiment, the granular material is comprised of prous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses.

  9. Mining dust filter. Bergbaustaubfilter

    Energy Technology Data Exchange (ETDEWEB)

    Igelbuescher, H.; Hoelter, H.

    1988-12-28

    A dust filter for application underground, whose casing is designed as a transportable unit combinable with further casings and fitted with removable filter pockets. These filter pockets have a frame which seals towards the casing and with the lattices on which the filter cloth is stretched and with spacers holding the said lattices at a distance. Each casing as such has inspection ports that are operationable optionally on either side, and clean and crude gas channels on its upper side. The ends of these channels have coupleable head pieces, so that connection is made easy when casings are arranged in a line. Each crude gas channel is connected to the inside of the casing by means of perforations in the floor of said channel, whereas the clean gas channel, for its part, is in connection with the inside of the casing by means of a channel on the head side of the casing. It is thus possible to create a dust filter having practically any desired output by arranging individual modules in line, in which connection each individual module is reliably transportable on the facilities available below ground, as pre-fabricated above ground. Stable support of the sides of the filter cloths is ensured by the lattice that consists of reciprocally cranked longitudinal and transverse wires. 10 figs.

  10. Low immediate scientific yield of the PhD among medical doctors

    DEFF Research Database (Denmark)

    Fosbol, Emil L.; Fosbøl, Philip Loldrup; Rerup, Sofie

    2016-01-01

    Background: We studied the scientific yield of the medical PhD program at all Danish Universities.Methods: We undertook a retrospective observational study. Three PhD schools in Denmark were included in order to evaluate the postdoctoral research production over more than 18 years through....... Scientific activity over time was assessed independently of author-rank and inactivity was measured relative to the date of graduation. Factors associated with inactivity were identified using multivariable logistic regression. 88.6 % of the PhD theses were conducted in internal medicine vs. 11.......12 (IQR 0.61-1.99) papers per year. About 2/3 of the graduates became inactive after 1 year and approximately 21 % of the graduates remained active during the whole follow-up. Female gender was associated with inactivity: adjusted odds ratio 1.59 (95 % confidence interval 1.24-2.05).Conclusions...

  11. Processamento radiográfico - câmara escura portátil: relação entre filtro de luz e densidade de base + véu Radiographic processing - portable darkroom: relation between light filtering and base density plus fog

    Directory of Open Access Journals (Sweden)

    José Roberto TAMBURÚS

    1999-01-01

    Full Text Available O objetivo desta pesquisa foi avaliar o efeito sobre a densidade de base + véu de filmes radiográficos, decorrente do uso da luz filtrada pelo polímero acrílico utilizado nas câmaras portáteis para processamento radiográfico. Filmes Kodak Ultra-speed e Ektaspeed Plus foram colocados no interior de uma câmara desse tipo e submetidos durante cinco minutos às condições de iluminação natural e artificial em que elas são rotineiramente utilizadas. Depois disso, os filmes foram processados pelo método temperatura-tempo em câmara escura convencional, juntamente com filmes dos mesmos grupos de sensibilidade que serviram como controle. Os valores densitométricos obtidos das amostras dos filmes foram analisados pelo teste de Mann-Whitney que indicou ao nível de 1% de significância, que os filmes submetidos às condições da câmara portátil apresentaram densidades de base + véu maiores em relação aos grupos controle. Os resultados mostraram que o filme Ektaspeed Plus apresentou valores maiores de densidade de base + véu em comparação com o filme Ultra-speed e que, embora o acrílico filtre a luz de forma similar ao filtro Kodak GBX 2, a maior intensidade de luz no interior da câmara escura portátil ocasionou o aumento na densidade de base + véu.The aim of this study was to assess the base density plus fog of dental X-ray films affected by light filtered through a commercial portable acrylic chamber used for radiography processing. Both Kodak Ultra-speed and Ektaspeed Plus films were placed into an acrylic chamber and submitted to the incidence of simultaneous natural and artificial light for five minutes to mimic a routine procedure in dental practice. Using a time/temperature method, these films were processed in a conventional darkroom together with films from the same sensitivity group that had not been subjected to light incidence (control. Densitometric values were obtained from all samples and the data were analysed by

  12. Science PhD career preferences: levels, changes, and advisor encouragement.

    Directory of Open Access Journals (Sweden)

    Henry Sauermann

    Full Text Available Even though academic research is often viewed as the preferred career path for PhD trained scientists, most U.S. graduates enter careers in industry, government, or "alternative careers." There has been a growing concern that these career patterns reflect fundamental imbalances between the supply of scientists seeking academic positions and the availability of such positions. However, while government statistics provide insights into realized career transitions, there is little systematic data on scientists' career preferences and thus on the degree to which there is a mismatch between observed career paths and scientists' preferences. Moreover, we lack systematic evidence whether career preferences adjust over the course of the PhD training and to what extent advisors exacerbate imbalances by encouraging their students to pursue academic positions. Based on a national survey of PhD students at tier-one U.S. institutions, we provide insights into the career preferences of junior scientists across the life sciences, physics, and chemistry. We also show that the attractiveness of academic careers decreases significantly over the course of the PhD program, despite the fact that advisors strongly encourage academic careers over non-academic careers. Our data provide an empirical basis for common concerns regarding labor market imbalances. Our results also suggest the need for mechanisms that provide PhD applicants with information that allows them to carefully weigh the costs and benefits of pursuing a PhD, as well as for mechanisms that complement the job market advice advisors give to their current students.

  13. Do PhD supervisors play a role in bridging academic cultures?

    DEFF Research Database (Denmark)

    Elliot, Dely; Kobayashi, Sofie

    , we strongly argue that PhD supervisors also have a significant part to play in facilitating successful transition of their PhD students to a new academic culture. Literature in doctoral education recognises the importance of ‘pastoral care’ in the supervisory bond for nurturing students’ overall...... learning, e.g. confidence and capacity-building in preparation for independent research (Cotterall, 2013; Wright, 2003). Pastoral care arguably includes supervisors’ efforts to facilitate the transition to the new learning environment. Yet, more in-depth examination of this aspect of the supervisory...

  14. The oxygen sensor PHD3 limits glycolysis under hypoxia via direct binding to pyruvate kinase

    Institute of Scientific and Technical Information of China (English)

    Nan Chen; Oliver Rinner; Dominika Czernik; Katarzyna J Nytko; Dan Zheng; Daniel P Stiehl; Nicola Zamboni; Matthias Gstaiger; Christian Frei

    2011-01-01

    @@ Dear Editor, Oxygen levels are critical for cellular physiology.Under low oxygen (hypoxia),cells increase glycolysis while limiting mitochondrial oxidative metabolism.Such adaptation is largely mediated by the transcription factors HIF,which accumulate under hypoxia [1,2].Prolyl hydroxylase domain proteins (PHD) function as cellular oxygen sensors and target HIF for subsequent degradation under normoxia [2].The PHD/HIF pathway is conserved in Drosophila,where a single prolyl hydroxylase,Fatiga,has been characterized.We have previously reported that Fatiga regulates cellular growth rates in a HIF-independent manner,yet mechanisms remained elusive [3].

  15. Empirical Essays on the Labor Market Outcomes of PhD Graduates

    DEFF Research Database (Denmark)

    Pedersen, Heidi Skovgaard

    During the past decade, policy makers have accentuated the need for more PhDs to drive innovation and use their research skills to push the technological frontier. The public sector in Denmark has financially supported a doubling of the number of enrolled PhD students based on a strong belief...... that PhDs accelerate growth. A major objective has been to direct more PhDs to the industry to use their skills to monetize knowledge. However, we have limited evidence on how PhDs are absorbed into the labor market, how the market values PhD labor, and how PhDs value the possibility to work...

  16. Top tips for PhD thesis examination: nurse clinicians, researchers and novices.

    Science.gov (United States)

    Cleary, Michelle; Horsfall, Jan; Hunt, Glenn E

    2012-01-01

    Interestingly, there are very few guidelines in the literature to assist novice nurse PhD examiners. In this paper, we aim to provide information to nurses, researchers or early career academics who have little experience in assessing a university thesis. The article provides background information about recent changes in the university sector; overviews some research on experienced examiners views; presents factors that differentiate between high and low quality PhD theses; and outlines some pointers that may be useful when marking at the doctoral level. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Education of MSc and PhD Students in Fluid Power and Mechatronics at DTU

    DEFF Research Database (Denmark)

    Conrad, Finn

    1996-01-01

    The paper deals with education of MSc and PhD students in engineering areas fluid power and mechatronics at the Technical Univ of Denmark, DTU, Lyngby. The new education structure and programs for MSc and PhD students adapted to the change and development of technologies. Focus is on two of twenty...... engineering profilies:(1) Engineeing Design and Product Development and (2)Control Engineering which give possibilitie for specialisation in fluid power and mechatronics design and productdevelopment. Synthesis, design and self-learning competency have a high priority taking the importance of training...

  18. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  19. Integrating the Projective Transform with Particle Filtering for Visual Tracking

    Directory of Open Access Journals (Sweden)

    Beghdadi A

    2011-01-01

    Full Text Available This paper presents the projective particle filter, a Bayesian filtering technique integrating the projective transform, which describes the distortion of vehicle trajectories on the camera plane. The characteristics inherent to traffic monitoring, and in particular the projective transform, are integrated in the particle filtering framework in order to improve the tracking robustness and accuracy. It is shown that the projective transform can be fully described by three parameters, namely, the angle of view, the height of the camera, and the ground distance to the first point of capture. This information is integrated in the importance density so as to explore the feature space more accurately. By providing a fine distribution of the samples in the feature space, the projective particle filter outperforms the standard particle filter on different tracking measures. First, the resampling frequency is reduced due to a better fit of the importance density for the estimation of the posterior density. Second, the mean squared error between the feature vector estimate and the true state is reduced compared to the estimate provided by the standard particle filter. Third, the tracking rate is improved for the projective particle filter, hence decreasing track loss.

  20. Fractional vortex dipole phase filter

    Science.gov (United States)

    Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam

    2014-10-01

    In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.

  1. An IIR median hybrid filter

    Science.gov (United States)

    Bauer, Peter H.; Sartori, Michael A.; Bryden, Timothy M.

    1992-01-01

    A new class of nonlinear filters, the so-called class of multidirectional infinite impulse response median hybrid filters, is presented and analyzed. The input signal is processed twice using a linear shift-invariant infinite impulse response filtering module: once with normal causality and a second time with inverted causality. The final output of the MIMH filter is the median of the two-directional outputs and the original input signal. Thus, the MIMH filter is a concatenation of linear filtering and nonlinear filtering (a median filtering module). Because of this unique scheme, the MIMH filter possesses many desirable properties which are both proven and analyzed (including impulse removal, step preservation, and noise suppression). A comparison to other existing median type filters is also provided.

  2. Two-zone pupil filters

    Science.gov (United States)

    Sheppard, Colin J. R.; Campos, Juan; Escalera, Juan C.; Ledesma, Silvia

    2008-03-01

    The performance of pupil filters consisting of two zones each of constant complex amplitude transmittance is investigated. For filters where the transmittance is real, different classes of potentially useful filter are identified and optimized. These include leaky filters with an inner zone of low amplitude transmittance, pure phase filters with phase change of π, and equal area filters. The first of these minimizes the relative power in the outer rings for a given axial resolution, the second maximizes the Strehl ratio for a given transverse resolution, and the third minimizes the relative power in the outer rings for a given transverse resolution. Complex filters can give an axially shifted maximum in intensity: the performance parameters calculated relative to the true focus are investigated for some different classes of filter, but filters with phase change not equal to π are found to give inferior performance to the real value filters.

  3. Remotely serviced filter and housing

    Science.gov (United States)

    Ross, M.J.; Zaladonis, L.A.

    1987-07-22

    A filter system for a hot cell comprises a housing adapted for input of air or other gas to be filtered, flow of the air through a filter element, and exit of filtered air. The housing is tapered at the top to make it easy to insert a filter cartridge holds the filter element while the air or other gas is passed through the filter element. Captive bolts in trunnion nuts are readily operated by electromechanical manipulators operating power wrenches to secure and release the filter cartridge. The filter cartridge is adapted to make it easy to change a filter element by using a master-slave manipulator at a shielded window station. 6 figs.

  4. The role of PHD2 mutations in the pathogenesis of erythrocytosis

    Directory of Open Access Journals (Sweden)

    Gardie B

    2014-07-01

    of EPO transcription. The α subunits of the hypoxia-inducible transcription factor are hydroxylated by three prolyl hydroxylase domain (PHD enzymes, which belong to the iron and 2-oxoglutarate-dependent oxygenase superfamily. Sequence analysis of the genes encoding the PHDs in patients with erythrocytosis has revealed heterozygous germline mutations only occurring in Egl nine homolog 1 (EGLN1, also known as PHD2, the gene that encodes PHD2. To date, 24 different EGLN1 mutations comprising missense, frameshift, and nonsense mutations have been described. The phenotypes associated with the patients carrying these mutations are fairly homogeneous and typically limited to erythrocytosis with normal to elevated EPO. However, exceptions exist; for example, there is one case with development of concurrent paraganglioma (PHD2-H374R. Analysis of the erythrocytosis-associated PHD2 missense mutations has shown heterogeneous results. Structural studies reveal that mutations can affect different domains of PHD2. Some are close to the hypoxia-inducible transcription factor α/2-oxoglutarate or the iron binding sites for PHD2. In silico studies demonstrate that the mutations do not always affect fully conserved residues. In vitro and in cellulo studies showed varying effects of the mutations, ranging from mild effects to severe loss of function. The exact mechanism of a potential tumor-suppressor role for PHD2 still needs to be elucidated. A knockin mouse model expressing the first reported PHD2-P317R mutation recapitulates the phenotype observed in humans (erythrocytosis with inappropriately normal serum EPO levels and demonstrates that haploinsufficiency and partial deregulation of PHD2 is sufficient to cause erythrocytosis. Keywords: PHD2, EGLN1, HIF, hypoxia, erythropoietin, erythrocytosis

  5. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  6. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon

    2016-01-08

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  7. NOTCH FILTER USING SIMULATED INDUCTOR

    Directory of Open Access Journals (Sweden)

    D.SUSAN,

    2011-06-01

    Full Text Available The design of analog filters at low frequencies is not possible because the size of inductors becomes very large. In such cases, the simulated inductors using operational amplifiers are used. This paper deals with the implementation of notch filter using band pass filter which uses simulated inductor where the direct implementation of notch filter using simulated inductor is not possible because of floating inductor. The design of notch filter and the simulation done in PSPICE is presented.

  8. Improved directional-distance filter

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper proposes a new spatial-distance weighting function.By combining the weighting function and the traditional directional-distance filter (DDF) in a novel way,a new vector filter-the adaptive distance-weighted directional-distance filter (ADWDDF)-is presented.The experimental results show that the proposed solution provides better filtering performance and preserves better image chromaticity and edge or detail information compared with the traditional DDF and some other typical vector filters.

  9. DOE HEPA filter test program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    This standard establishes essential elements of a Department of Energy (DOE) program for testing HEPA filters to be installed in DOE nuclear facilities or used in DOE-contracted activities. A key element is the testing of HEPA filters for performance at a DOE Filter Test Facility (FTF) prior to installation. Other key elements are (1) providing for a DOE HEPA filter procurement program, and (2) verifying that HEPA filters to be installed in nuclear facilities appear on a Qualified Products List (QPL).

  10. Multivariate density estimation theory, practice, and visualization

    CERN Document Server

    Scott, David W

    2015-01-01

    David W. Scott, PhD, is Noah Harding Professor in the Department of Statistics at Rice University. The author of over 100 published articles, papers, and book chapters, Dr. Scott is also Fellow of the American Statistical Association (ASA) and the Institute of Mathematical Statistics. He is recipient of the ASA Founder's Award and the Army Wilks Award. His research interests include computational statistics, data visualization, and density estimation. Dr. Scott is also Coeditor of Wiley Interdisciplinary Reviews: Computational Statistics and previous Editor of the Journal of Computational and

  11. The Benefits of Publishing Systematic Quantitative Literature Reviews for PhD Candidates and Other Early-Career Researchers

    Science.gov (United States)

    Pickering, Catherine; Byrne, Jason

    2014-01-01

    Universities increasingly expect students to publish during a PhD candidature because it benefits the candidate, supervisor, institution, and wider community. Here, we describe a method successfully used by early-career researchers including PhD candidates to undertake and publish literature reviews--a challenge for researchers new to a field. Our…

  12. PhD Crisis Discourse: A Critical Approach to the Framing of the Problem and Some Australian "Solutions"

    Science.gov (United States)

    Cuthbert, Denise; Molla, Tebeje

    2015-01-01

    A feature of HE reform discourse is the tendency to construct the rationale for reform in terms of averting calamity and risk. We refer to this risk talk as "crisis discourse." This study examines the formulation of PhD crisis discourse internationally and in Australia. We find that a key feature of PhD crisis discourse is that…

  13. Prolyl Hydroxylase Domain-Containing Protein 2 (Phd2) Regulates Chondrocyte Differentiation and Secondary Ossification in Mice

    Science.gov (United States)

    Cheng, Shaohong; Aghajanian, Patrick; Pourteymoor, Sheila; Alarcon, Catrina; Mohan, Subburaman

    2016-01-01

    Endochondral ossification plays an important role in the formation of the primary ossification centers (POCs) and secondary ossification centers (SOCs) of mammalian long bones. However, the molecular mechanisms that regulate POC and SOC formation are different. We recently demonstrated that Prolyl Hydroxylase Domain-containing Protein 2 (Phd2) is a key mediator of vitamin C effects on bone. We investigated the role of Phd2 on endochondral ossification of the epiphyses by conditionally deleting the Phd2 gene in osteoblasts and chondrocytes. We found that the deletion of Phd2 in osteoblasts did not cause changes in bone parameters in the proximal tibial epiphyses in 5 week old mice. In contrast, deletion of Phd2 in chondrocytes resulted in increased bone mass and bone formation rate (normalized to tissue volume) in long bone epiphyses, indicating that Phd2 expressed in chondrocytes, but not osteoblasts, negatively regulates secondary ossification of epiphyses. Phd2 deletion in chondrocytes elevated mRNA expression of hypoxia-inducible factor (HIF) signaling molecules including Hif-1α, Hif-2α, Vegfa, Vegfb, and Epo, as well as markers for chondrocyte hypertrophy and mineralization such as Col10, osterix, alkaline phosphatase, and bone sialoprotein. These data suggest that Phd2 expressed in chondrocytes inhibits endochondral ossification at the epiphysis by suppressing HIF signaling pathways. PMID:27775044

  14. A Networked Pathway to the PhD: The African-Norwegian Case of Productive Learning Cultures

    Science.gov (United States)

    Hattingh, Annemarie; Lillejord, Solvi

    2011-01-01

    How do PhD students become socialised into the professional world of academic work? This article pays attention to a "networked" support pathway towards a PhD. The network constitutes an international research collaboration through a programme called Productive Learning Cultures (PLC) (2002-2011) between Norway and seven countries,…

  15. Publishing and Learning Writing for Publication in English: Perspectives of NNES PhD Students in Science

    Science.gov (United States)

    Huang, Ju Chuan

    2010-01-01

    Publication in international journals has become a prerequisite to PhD graduation. This study thus provides a framework for understanding the learning of writing skills and publishing practices of nonnative English-speaking PhD students by investigating their perceptions of publishing and learning to write for publication. Findings show that these…

  16. Improved image filter based on SPCNN

    Institute of Scientific and Technical Information of China (English)

    ZHANG YuDong; WU LeNan

    2008-01-01

    By extraction of the thoughts of non-linear model and adaptive model match, an improved Nagao filter is brought. Meanwhile a technique based on simplified pulse coupled neural network and used for noise positioning, is put forward. Combining the two methods above, we acquire a new method that can restore images corrupted by salt and pepper noise. Experiments show that this method is more preferable than other popular ones, and still works well while noise density fluctuates severely.

  17. A filter for use in lateral cephalography

    Energy Technology Data Exchange (ETDEWEB)

    Tanimoto, K.; Ogawa, M.; Kodera, Y.; Tomita, S.; Wada, T. (Hiroshima Univ. (Japan))

    1989-11-01

    A new filter was devised for density compensation and absorbed-dose reduction in cephalometric radiographs. It is composed of a rare earth screen that plays a role in depicting soft tissue shadows and cephalometric points. The greatest reduction of the absorbed dose was about one seventh at the tube side of the thyroid gland when it was included in the direct x-ray beam. Smaller collimation was the most important factor in reducing the absorbed dose.

  18. Stack filter classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory

    2009-01-01

    Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

  19. Automated electronic filter design

    CERN Document Server

    Banerjee, Amal

    2017-01-01

    This book describes a novel, efficient and powerful scheme for designing and evaluating the performance characteristics of any electronic filter designed with predefined specifications. The author explains techniques that enable readers to eliminate complicated manual, and thus error-prone and time-consuming, steps of traditional design techniques. The presentation includes demonstration of efficient automation, using an ANSI C language program, which accepts any filter design specification (e.g. Chebyschev low-pass filter, cut-off frequency, pass-band ripple etc.) as input and generates as output a SPICE(Simulation Program with Integrated Circuit Emphasis) format netlist. Readers then can use this netlist to run simulations with any version of the popular SPICE simulator, increasing accuracy of the final results, without violating any of the key principles of the traditional design scheme.

  20. 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...

  1. Factors Affecting Timely Completion of a PhD: A Complex Systems Approach

    Science.gov (United States)

    Pitchforth, Jegar; Beames, Stephanie; Thomas, Aleysha; Falk, Matthew; Farr, Charisse; Gasson, Susan; Thamrin, Sri Astuti; Mengersen, Kerrie

    2012-01-01

    Completing a PhD on time is a complex process, influenced by many interacting factors. In this paper we take a Bayesian Network approach to analyzing the factors perceived to be important in achieving this aim. Focusing on a single research group in Mathematical Sciences, we develop a conceptual model to describe the factors considered to be…

  2. Factors Influencing International PhD Students to Study Physics in Australia

    Science.gov (United States)

    Choi, Serene H.-J.; Nieminen, Timo A.; Townson, Peter

    2012-01-01

    Since physics research is an activity of an active international community, international visits are a common way for physicists to share scientific knowledge and skills. International mobility of physicists is also important for PhD physics study and research training. We investigated personal and social factors that influenced the decision for…

  3. International Students' Motivation to Pursue and Complete a Ph.D. in the U.S.

    Science.gov (United States)

    Zhou, Ji

    2015-01-01

    This study explores what motivates 19 international students to pursue a Ph.D. at a public research university in the U.S. and, more importantly, what motivates them to persist despite unsatisfying socialization. Based on value-expectancy achievement motivation theory, four motivations emerged: intrinsic interest in research, intrinsic interest in…

  4. Constructing an Institutional Identity in University Tea Rooms: The International PhD Student Experience

    Science.gov (United States)

    Fotovatian, Sepideh; Miller, Jenny

    2014-01-01

    This case study profiles eight international PhD students and describes the process of the construction and negotiation of their social and institutional identities in an Australian university. Audio-recorded informal conversations of the students highlight the role of social membership, staffroom interactions and language in the construction of…

  5. Hypoxia and loss of PHD2 inactivate stromal fibroblasts to decrease tumour stiffness and metastasis.

    Science.gov (United States)

    Madsen, Chris D; Pedersen, Jesper T; Venning, Freja A; Singh, Lukram Babloo; Moeendarbary, Emad; Charras, Guillaume; Cox, Thomas R; Sahai, Erik; Erler, Janine T

    2015-10-01

    Cancer-associated fibroblasts (CAFs) interact with tumour cells and promote growth and metastasis. Here, we show that CAF activation is reversible: chronic hypoxia deactivates CAFs, resulting in the loss of contractile force, reduced remodelling of the surrounding extracellular matrix and, ultimately, impaired CAF-mediated cancer cell invasion. Hypoxia inhibits prolyl hydroxylase domain protein 2 (PHD2), leading to hypoxia-inducible factor (HIF)-1α stabilisation, reduced expression of αSMA and periostin, and reduced myosin II activity. Loss of PHD2 in CAFs phenocopies the effects of hypoxia, which can be prevented by simultaneous depletion of HIF-1α. Treatment with the PHD inhibitor DMOG in an orthotopic breast cancer model significantly decreases spontaneous metastases to the lungs and liver, associated with decreased tumour stiffness and fibroblast activation. PHD2 depletion in CAFs co-injected with tumour cells similarly prevents CAF-induced metastasis to lungs and liver. Our data argue that reversion of CAFs towards a less active state is possible and could have important clinical implications.

  6. Career Aspirations and Career Outcomes for Solar and Space Physics Ph.D

    Science.gov (United States)

    Moldwin, M.; Morrow, C. A.

    2013-12-01

    Results from a recent graduate student survey found unsurprisingly that Solar and Space Physics (S&SP) Ph.D. graduate students almost all aspire to have research careers in Solar and Space Physics. This study reports on the research career outcomes over the last decade for S&SP Ph.Ds. We used publication of peer-reviewed articles as the indicator for persistence in a research career. We found that nearly two-thirds (64%) of Ph.D.s who graduated between 2001 to 2009 published refereed-papers four or more years after their Ph.D., while 17% of Ph.D.s never published another paper beyond the year they received their Ph.D. The remaining 19% of Ph.Ds, stopped publishing within three-years of receiving their Ph.D. We found that though there is statistically no difference on persistence of publishing research between graduates of the largest programs compared to all other programs, there are significant differences between programs. We also found there was no gender differences in any of the persistence data (i.e., men and women stop or continue publishing at the same rates). Graduate programs, faculty advisors and potential graduate students can use these data for career planning. This study suggests that a significant majority of S&SP Ph.D.s (77%) find post-doctoral research positions and a majority (56%) find research careers beyond their post-doc.

  7. Competitive binding of a benzimidazole to the histone-binding pocket of the Pygo PHD finger.

    Science.gov (United States)

    Miller, Thomas C R; Rutherford, Trevor J; Birchall, Kristian; Chugh, Jasveen; Fiedler, Marc; Bienz, Mariann

    2014-12-19

    The Pygo-BCL9 complex is a chromatin reader, facilitating β-catenin-mediated oncogenesis, and is thus emerging as a potential therapeutic target for cancer. Its function relies on two ligand-binding surfaces of Pygo's PHD finger that anchor the histone H3 tail methylated at lysine 4 (H3K4me) with assistance from the BCL9 HD1 domain. Here, we report the first use of fragment-based screening by NMR to identify small molecules that block protein-protein interactions by a PHD finger. This led to the discovery of a set of benzothiazoles that bind to a cleft emanating from the PHD-HD1 interface, as defined by X-ray crystallography. Furthermore, we discovered a benzimidazole that docks into the H3K4me specificity pocket and displaces the native H3K4me peptide from the PHD finger. Our study demonstrates the ligandability of the Pygo-BCL9 complex and uncovers a privileged scaffold as a template for future development of lead inhibitors of oncogenesis.

  8. Three new students selected for the ATLAS PhD Grant Scheme

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Initiated in 2013, the ATLAS PhD Grant Scheme aims to enable young, talented and motivated students to work on part of their PhD thesis at CERN. The collaboration has just selected the three students who will start their theses in 2016.   The three students who received the ATLAS grant, which will cover part of their PhD studies. From left to right: Ruth Jacobs (Germany), Artem Basalaev (Russia), Nedaa B I Asbah (Palestine). The ATLAS PhD Grant Scheme was made possible thanks to a large donation by former ATLAS spokespersons Fabiola Gianotti and Peter Jenni, who started the fund with money from the Fundamental Physics Prize they received in 2013. Applications are handled by CERN HR, via this link. The aim of the initiative is to offer a unique educational opportunity to students within the ATLAS collaboration and to give them the possibility to continue their career in particle physics. Selected candidates receive a stipend allowing them to spend one year at CERN, followed by one year at their h...

  9. PhD and the Manager's Dream: Professionalising the Students, the Degree and the Supervisors?

    Science.gov (United States)

    Matos, Frederico

    2013-01-01

    This article has two main aims: to analyse relevant literature on the doctoral degree, and to assess whether recent funding changes in the UK have changed the nature of the PhD in the social sciences in a research-intensive and prestigious UK university. Data were collected at BlueSkies University where interviews with social sciences PhD…

  10. Ph.D. Thesis: Quantum Field Theory and Gravity in Causal Sets

    CERN Document Server

    Sverdlov, Roman

    2009-01-01

    This is is a copy of dissertation that I have submitted in defense of my ph.d. thesis, with some minor changes that I have made since then. The goal of the project is to generalize matter fields and their Lagrangians from regular space time to causal sets.

  11. Ph.D. Thesis: Quantum Field Theory and Gravity in Causal Sets

    Science.gov (United States)

    Sverdlov, Roman

    2009-05-01

    This is is a copy of dissertation that I have submitted in defense of my ph.d. thesis, with some minor changes that I have made since then. The goal of the project is to generalize matter fields and their Lagrangians from regular space time to causal sets.

  12. Winning the PhD Game: Evocative Playing of Snakes and Ladders

    Science.gov (United States)

    Dickie, Carolyn

    2011-01-01

    The purpose of this paper is to describe a qualitative approach to developing an understanding of the lived experiences of PhD students. Rather than relying on textbook reports and theories about studying a higher degree by research, by allowing the students' voices to be heard, explicit and conscious research can be used to generate appropriate…

  13. The New Debate: The PhD versus the MFA Degree.

    Science.gov (United States)

    Barranger, Milly S.; And Others

    1986-01-01

    Introduces and includes "The Ritz Bar or ABD: In Defense of the MFA," in which Peter Garvie defends the professionalism of the MFA degree in theatre, and "The PhD in Theatre--A Vanishing Degree?" Richard Hornby's discussion of the importance of the doctoral degree as the standard teaching degree. (PD)

  14. At the MLA, a Ph.D. Candidate Navigates the Jobs Gantlet

    Science.gov (United States)

    Patton, Stacey

    2012-01-01

    It's the night before one of Javier Jimenez's big job interviews at the Modern Language Association (MLA) meeting. The 35-year-old graduate student, who is scheduled to earn his Ph.D. in comparative literature this spring from the University of California at Berkeley, is trying to ward off anxiety and abdominal pains. The mystique of the MLA, the…

  15. The Future of Rhetoric in English Department Ph.D. Programs.

    Science.gov (United States)

    Clark, Suzanne

    1995-01-01

    Offers a utopian vision of what the place of rhetoric should be in a department that thinks of itself as literary. Argues that a Ph.D. in English that encompasses both literature and rhetoric works because it is really a degree in rhetoric. (TB)

  16. Career-Self Management and Entrepreneurship: An Experience with PhD Students

    Science.gov (United States)

    Pinto, Joana Carneiro; do Ceu Taveira, Maria; Sa, Elisabete

    2012-01-01

    Introduction: This study presents an experience developed with PhD students aimed to analyze the extent to which career self-management should be approached along with entrepreneurship issues to promote students' career development. Method: An intervention group who attended a Career Self-Management Seminar (EG1), a comparison group who attended…

  17. From Student to Scholar: The Academic Library and Social Sciences PhD Students' Transformation

    Science.gov (United States)

    Fleming-May, Rachel; Yuro, Lisa

    2009-01-01

    Although research concerning the information-seeking behavior of academic library users is abundant, few studies have focused specifically on PhD students. This oversight has had an impact on librarians' ability to effectively market services such as information literacy instruction and research assistance to doctoral students. In order to…

  18. Regulating Emotions and Aiming for a Ph.D.: Excerpts from "Anthropology Matters"

    Science.gov (United States)

    Hovland, Ingie

    2012-01-01

    In this article I will present a range of experiences of graduate socialisation that have been discussed in past articles in the journal "Anthropology Matters". These are the experiences of social anthropology Ph.D. students in the United Kingdom. The overarching theme for the article is "regulating emotions", and the excerpts…

  19. PhD versus DSW: A Critique of Trends in Social Work Doctoral Education

    Science.gov (United States)

    Howard, Tyriesa

    2016-01-01

    Social work educators are in a phase of reintroducing the doctor of social work (DSW) degree and refining distinctions between PhD and DSW doctoral programs. This article examines how the two options have been prey to a noticeable "seesaw of precedence", resulting in a debatable history of social work's approach to doctoral education…

  20. Temporary contracts : Effect on job satisfaction and personal lives of recent PhD graduates

    NARCIS (Netherlands)

    Waaijer, C.J.F.; Belder, R.; Sonneveld, H.; Van, Bochove C.A.; Van, der Weijden I.C.M.

    2017-01-01

    In this study, we assess the effects of temporary employment on job satisfaction and the personal lives of recent PhD graduates. Temporary employment is becoming increasingly prevalent in many sectors, but has been relatively common in academia, especially for early career scientists. Labor market

  1. Regulating Emotions and Aiming for a Ph.D.: Excerpts from "Anthropology Matters"

    Science.gov (United States)

    Hovland, Ingie

    2012-01-01

    In this article I will present a range of experiences of graduate socialisation that have been discussed in past articles in the journal "Anthropology Matters". These are the experiences of social anthropology Ph.D. students in the United Kingdom. The overarching theme for the article is "regulating emotions", and the excerpts…

  2. The Impact of Publishing during PhD Studies on Career Research Publication, Visibility, and Collaborations

    Science.gov (United States)

    Horta, Hugo; Santos, João M.

    2016-01-01

    This study analyzes the impact that publishing during the period of PhD study has on researchers' future knowledge production, impact, and co-authorship. The analysis is based on a representative sample of PhDs from all fields of science working in Portugal. For each researcher in the dataset, we compiled a lifetime publication record and…

  3. A model perception on the independence of PhD students in ...

    African Journals Online (AJOL)

    Amy Stambach

    It is familiar that PhD students from University of Rwanda (UR) are used to ... from the beginning of doctoral studies until the successful completion by .... completion of a research degree and one shall have taken an approved and certified course on ... In addition to the supervisors, an adviser or advisers may be proposed to ...

  4. The Focus and Substance of Formative Comment Provided by PhD Examiners

    Science.gov (United States)

    Holbrook, Allyson; Bourke, Sid; Fairbairn, Hedy; Lovat, Terence

    2014-01-01

    In practice and process PhD examination is distinctive, reflecting the high expectations of students whose learning has been directed to their becoming researchers. This article builds on previous research on the examination of Australian theses that revealed that examiners in Science (n?=?542) and Education (n?=?241) provide a substantial…

  5. International Students' Motivation to Pursue and Complete a Ph.D. in the U.S.

    Science.gov (United States)

    Zhou, Ji

    2015-01-01

    This study explores what motivates 19 international students to pursue a Ph.D. at a public research university in the U.S. and, more importantly, what motivates them to persist despite unsatisfying socialization. Based on value-expectancy achievement motivation theory, four motivations emerged: intrinsic interest in research, intrinsic interest in…

  6. Completing a PhD by Publication: A Review of Australian Policy and Implications for Practice

    Science.gov (United States)

    Jackson, Denise

    2013-01-01

    There is increasing impetus for higher-degree-by-research students to publish during candidature. Research performance, including higher degree completions and publication output, commonly determines university funding, and doctorates with publishing experience are better positioned for a career in softening academic labour markets. The PhD by…

  7. Regulating Emotions and Aiming for a Ph.D.: Excerpts from "Anthropology Matters"

    Science.gov (United States)

    Hovland, Ingie

    2012-01-01

    In this article I will present a range of experiences of graduate socialisation that have been discussed in past articles in the journal "Anthropology Matters". These are the experiences of social anthropology Ph.D. students in the United Kingdom. The overarching theme for the article is "regulating emotions", and the excerpts presented illustrate…

  8. COMPARISON OF HEDGES IN M.A. THESES AND PH.D. DISSERTATIONS IN ELT

    Directory of Open Access Journals (Sweden)

    Çağla ATMACA

    2016-08-01

    Full Text Available Writers use some textual devices like hedges and boosters in order to contribute to their textual voice. Differences between M.A. theses and Ph.D. dissertations in English Language Teaching (ELT Department in terms of hedges in Turkish context seem to be an overlooked area. Thus, this paper aims to find the similarities and differences between M.A. theses and Ph.D. dissertations about English Language Teaching in terms of hedges. For this purpose, 10 M.A. theses and 10 Ph.D. dissertations were randomly chosen. Data were analyzed and categorized on the basis of contextual features with the help of content analysis. Various hedging tools emerged as a result of content analysis and it was found that hedges used in the Ph.D. dissertations nearly double those in the M.A. theses. Moreover, modals -followed by passivization- are the leading form of hedging while nouns have the least frequency of hedging type, which could explain some of the differences between novice and experienced writers. In the light of these findings, important implications are drawn for graduate and postgraduate students to enhance their writing skills and be familiar with the principles of academic writing for their future career.

  9. Ability, academic climate, and going abroad for work or pursuing a PhD

    NARCIS (Netherlands)

    Bertrand-Cloodt, D.A.M.; Cörvers, F.; Heijke, J.A.M.

    2014-01-01

    We investigate whether a creaming off of highly able students from Dutch universities is taking place. Therefore, we examine the relation between ability and the destination of recent graduates of Dutch universities. Students can choose to continue their academic career by investing in a PhD degree

  10. Ability, academic climate, and going abroad for work or pursuing a PhD

    NARCIS (Netherlands)

    Bertrand - Cloodt, Danielle; Cörvers, Frank; Heijke, Hans

    We investigate whether highly able students are being creamed off from Dutch universities. Therefore, we examine the relation between ability and the destination of recent graduates of Dutch universities. Students can choose to continue their academic career by investing in a PhD degree instead of

  11. Learning Opportunities in PhD Supervisory Talks: A Social Constructionist Perspective

    Science.gov (United States)

    Tian, Wenwen; Singhasiri, Wareesiri

    2016-01-01

    Although PhD supervision has been recognised as an educative process and a complex pedagogy for decades, there is little research into on-site pedagogic processes. Informed by social constructionism and a Foucauldian approach, this qualitative case study explores how learning opportunities were created by analysing both a supervisor's verbal…

  12. Ensuring PhD development of responsible conduct of research behaviors: who's responsible?

    Science.gov (United States)

    Titus, Sandra L; Ballou, Janice M

    2014-03-01

    The importance of public confidence in scientific findings and trust in scientists cannot be overstated. Thus, it becomes critical for the scientific community to focus on enhancing the strategies used to educate future scientists on ethical research behaviors. What we are lacking is knowledge on how faculty members shape and develop ethical research standards with their students. We are presenting the results of a survey with 3,500 research faculty members. We believe this is the first report on how faculty work with and educate their PhD students on basic research standards. Specifically, we wanted to determine whether individual faculty members, who are advisors or mentors, differ in how they implemented components of responsible conduct of research (RCR) with their PhD students. Mentors were more likely than advisors or supervisors to report working with all of their PhDs, who graduated in the last 5 years, on the 17 recognized critical components of RCR training and research skill development. We also found about half of the faculty members believe RCR is an institutional responsibility versus a faculty responsibility. Less than a quarter have had opportunities to participate in faculty training to be a better mentor, advisor, or research teacher, and about one third of faculty did not or could not remember whether they had guidelines related to their responsibilities to PhD students. We discuss the implications of our findings and focus on ways that PhD research mentoring can be enhanced.

  13. Ability, academic climate, and going abroad for work or pursuing a PhD

    NARCIS (Netherlands)

    Bertrand-Cloodt, D.A.M.; Cörvers, F.; Heijke, J.A.M.

    2014-01-01

    We investigate whether a creaming off of highly able students from Dutch universities is taking place. Therefore, we examine the relation between ability and the destination of recent graduates of Dutch universities. Students can choose to continue their academic career by investing in a PhD degree

  14. The first recipients of the ATLAS PhD Grant Scholarship Programme 2014

    CERN Multimedia

    Marcelloni, Claudia

    2014-01-01

    First recipients of the ATLAS PhD Grant Scholarship 2014 : With certificates, Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James PurvisProgramme: Lailin Xu, Josefina Alconada, and Gagik Vardanyan

  15. A Concept of Approximated Densities for Efficient Nonlinear Estimation

    Directory of Open Access Journals (Sweden)

    Virginie F. Ruiz

    2002-10-01

    Full Text Available This paper presents the theoretical development of a nonlinear adaptive filter based on a concept of filtering by approximated densities (FAD. The most common procedures for nonlinear estimation apply the extended Kalman filter. As opposed to conventional techniques, the proposed recursive algorithm does not require any linearisation. The prediction uses a maximum entropy principle subject to constraints. Thus, the densities created are of an exponential type and depend on a finite number of parameters. The filtering yields recursive equations involving these parameters. The update applies the Bayes theorem. Through simulation on a generic exponential model, the proposed nonlinear filter is implemented and the results prove to be superior to that of the extended Kalman filter and a class of nonlinear filters based on partitioning algorithms.

  16. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  17. Airborne Crowd Density Estimation

    Science.gov (United States)

    Meynberg, O.; Kuschk, G.

    2013-10-01

    This paper proposes a new method for estimating human crowd densities from aerial imagery. Applications benefiting from an accurate crowd monitoring system are mainly found in the security sector. Normally crowd density estimation is done through in-situ camera systems mounted on high locations although this is not appropriate in case of very large crowds with thousands of people. Using airborne camera systems in these scenarios is a new research topic. Our method uses a preliminary filtering of the whole image space by suitable and fast interest point detection resulting in a number of image regions, possibly containing human crowds. Validation of these candidates is done by transforming the corresponding image patches into a low-dimensional and discriminative feature space and classifying the results using a support vector machine (SVM). The feature space is spanned by texture features computed by applying a Gabor filter bank with varying scale and orientation to the image patches. For evaluation, we use 5 different image datasets acquired by the 3K+ aerial camera system of the German Aerospace Center during real mass events like concerts or football games. To evaluate the robustness and generality of our method, these datasets are taken from different flight heights between 800 m and 1500 m above ground (keeping a fixed focal length) and varying daylight and shadow conditions. The results of our crowd density estimation are evaluated against a reference data set obtained by manually labeling tens of thousands individual persons in the corresponding datasets and show that our method is able to estimate human crowd densities in challenging realistic scenarios.

  18. Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

    Directory of Open Access Journals (Sweden)

    Gonzalez Juan G

    2002-01-01

    Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the -stable and generalized- . We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the "normal" equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

  19. Exploring challenges of the reproductive health PhD curriculum: A qualitative research

    Directory of Open Access Journals (Sweden)

    Sh Kohan

    2016-07-01

    Full Text Available Introduction: Enhancing the quality and dynamicity of higher education programs requires continuous evaluation of curriculums. Reproductive health PhD program was established in 2006 in Iran while recommending that its curriculum be evaluated by assessing graduates’ performance in workplace and surveying students, faculty members and managers. This study aimed to explore challenges of the curriculum of reproductive health PhD program. Methods: Employing a qualitative content analysis approach and using purposive and sometimes opportunistic sampling, experiences and viewpoints of 33 graduates and students of reproductive health PhD program, educational managers and reproductive health board members about the curriculum of reproductive health PhD program were collected through individual interviews and notes in 2014-15. Data were transcribed and important expressions were coded. Classification of similar codes led to preliminary categories. Five main categories were extracted by further classifications. Results: The five main categories included inadequacy of course topics and contents, challenges of student education, failure in realizing curriculum goals, long research period, and ambiguity in graduates’ professional status were appeared; each of these included various subcategories. Conclusion: Results showed that the curriculum of reproductive health PhD program required revisions to meet the program’s mission and designing courses such as sexual health and reinforcing the clinical nature of the program were necessary. Moreover, the results emphasized that the establishment of an independent educational department of reproductive health for managing higher education affairs and greater supervision of the reproductive health board on educational affairs was necessary. Furthermore, reproductive health specialists should be employed in different positions to meet society’s reproductive health needs.

  20. [Research misconduct: Knowledge, actions and attitudes of PhD candidates].

    Science.gov (United States)

    Hofmann, Bjørn; Holm, Søren

    2016-09-01

    BACKGROUND Increasing attention is being paid to research misconduct in academic journals and in the media, but we know relatively little about its extent or attitudes to research misconduct, or how these are changing. This study therefore aims to investigate PhD candidates' knowledge, own actions and attitudes to specific forms of research misconduct.MATERIAL AND METHOD In autumn 2015, an anonymous questionnaire survey was distributed to all participants in the introductory course for PhD candidates at the Faculty of Medicine at the University of Oslo.RESULTS Altogether 77 PhD candidates (79 %) responded to the questionnaire. A total of 62 % conducted clinical research and 25 % conducted basic research. Around one in four had heard about serious forms of research misconduct in the previous year, and around 4 % were aware of various forms of serious research misconduct in their own department in the previous year. Compared to earlier studies, an increasing number (16 %) responded that they had been subjected to unethical pressure with regard to inclusion or order of authors. Approximately two-thirds were uncertain of whether their department had written policies for academic conduct. One-third of PhD candidates did not disassociate themselves from actions that are generally viewed as scientific misconduct. One-tenth thought it acceptable to falsify or fabricate data in order to expedite publication, one-fifth did not object to taking the credit for others' ideas, and almost half did not believe it was wrong to attempt a number of methods of analysis until one arrived at a significant answer.INTERPRETATION PhD candidates at the Faculty of Medicine were aware of research misconduct, both generally and from their own department. They themselves reported some type of scientific misconduct, and a large majority were uncertain of their department's guidelines. Some of the candidates also accepted several forms of research misconduct.

  1. Skill development in collaborative research projects: A comparison between PhD students in multi-actor research programs and in traditional trajectories

    OpenAIRE

    Wardenaar, T.; Belder, R.; de Goede, M.E.E; Horlings, E.; van den Besselaar, P.

    2014-01-01

    The growing number of PhD students has spurred debates about the societal relevance of PhD training trajectories. The academic labour market does not provide enough jobs and many PhD graduates will have a career outside academia. It has been questioned whether current PhD training trajectories are still adequate and collaborative research projects are introduced as alternative trajectories. Such trajectories can support the development of a broader set of skills, but might have adverse effect...

  2. Domain wall filters

    CERN Document Server

    Bär, O; Neuberger, H; Witzel, O; Baer, Oliver; Narayanan, Rajamani; Neuberger, Herbert; Witzel, Oliver

    2007-01-01

    We propose using the extra dimension separating the domain walls carrying lattice quarks of opposite handedness to gradually filter out the ultraviolet fluctuations of the gauge fields that are felt by the fermionic excitations living in the bulk. This generalization of the homogeneous domain wall construction has some theoretical features that seem nontrivial.

  3. Fast Anisotropic Gauss Filters

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.

    2003-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computing perspective. An implementation scheme for normal covolution and f

  4. Ceramic HEPA Filter Program

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, M A; Bergman, W; Haslam, J; Brown, E P; Sawyer, S; Beaulieu, R; Althouse, P; Meike, A

    2012-04-30

    Potential benefits of ceramic filters in nuclear facilities: (1) Short term benefit for DOE, NRC, and industry - (a) CalPoly HTTU provides unique testing capability to answer questions for DOE - High temperature testing of materials, components, filter, (b) Several DNFSB correspondences and presentations by DNFSB members have highlighted the need for HEPA filter R and D - DNFSB Recommendation 2009-2 highlighted a nuclear facility response to an evaluation basis earthquake followed by a fire (aka shake-n-bake) and CalPoly has capability for a shake-n-bake test; (2) Intermediate term benefit for DOE and industry - (a) Filtration for specialty applications, e.g., explosive applications at Nevada, (b) Spin-off technologies applicable to other commercial industries; and (3) Long term benefit for DOE, NRC, and industry - (a) Across industry, strong desire for better performance filter, (b) Engineering solution to safety problem will improve facility safety and decrease dependence on associated support systems, (c) Large potential life-cycle cost savings, and (d) Facilitates development and deployment of LLNL process innovations to allow continuous ventilation system operation during a fire.

  5. Magnetic-Optical Filter

    CERN Document Server

    Formicola, I; Pinto, C; Cerulo, P

    2007-01-01

    Magnetic-Optical Filter (MOF) is an instrument suited for high precision spectral measurements for its peculiar characteristics. It is employed in Astronomy and in the field of the telecommunications (it is called FADOF there). In this brief paper we summarize its fundamental structure and functioning.

  6. Enhanced Optical Filter Design

    CERN Document Server

    Cushing, David

    2011-01-01

    This book serves as a supplement to the classic texts by Angus Macleod and Philip Baumeister, taking an intuitive approach to the enhancement of optical coating (or filter) performance. Drawing from 40 years of experience in thin film design, Cushing introduces the basics of thin films, the commonly used materials and their deposition, the major coatings and their applications, and improvement methods for each.

  7. Ozone decomposing filter

    Science.gov (United States)

    Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.

    1999-01-01

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  8. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2014-01-01

    Full Text Available A major security challenge on the Internet is the existence of the large number of compromised machines. Such machines have been increasingly used to launch various security attacks including spamming and spreading malware, DDoS, and identity theft. These compromised machines are called “Zombies”. In general E-mail applications and providers uses spam filters to filter the spam messages. Spam filtering is a technique for discriminating the genuine message from the spam messages. The attackers send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  9. Digital hum filtering

    Science.gov (United States)

    Knapp, R.W.; Anderson, N.L.

    1994-01-01

    Data may be overprinted by a steady-state cyclical noise (hum). Steady-state indicates that the noise is invariant with time; its attributes, frequency, amplitude, and phase, do not change with time. Hum recorded on seismic data usually is powerline noise and associated higher harmonics; leakage from full-waveform rectified cathodic protection devices that contain the odd higher harmonics of powerline frequencies; or vibrational noise from mechanical devices. The fundamental frequency of powerline hum may be removed during data acquisition with the use of notch filters. Unfortunately, notch filters do not discriminate signal and noise, attenuating both. They also distort adjacent frequencies by phase shifting. Finally, they attenuate only the fundamental mode of the powerline noise; higher harmonics and frequencies other than that of powerlines are not removed. Digital notch filters, applied during processing, have many of the same problems as analog filters applied in the field. The method described here removes hum of a particular frequency. Hum attributes are measured by discrete Fourier analysis, and the hum is canceled from the data by subtraction. Errors are slight and the result of the presence of (random) noise in the window or asynchrony of the hum and data sampling. Error is minimized by increasing window size or by resampling to a finer interval. Errors affect the degree of hum attenuation, not the signal. The residual is steady-state hum of the same frequency. ?? 1994.

  10. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2015-10-01

    Full Text Available A major security challenge on the Internet is the existence of the large number of compromised machines. Such machines have been increasingly used to launch various security attacks including spamming and spreading malware, DDoS, and identity theft. These compromised machines are called "Zombies". In general E-mail applications and providers uses spam filters to filter the spam messages. Spam filtering is a technique for discriminating the genuine message from the spam messages. The attackers send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  11. Communication theory of quantum systems. Ph.D. Thesis, 1970

    Science.gov (United States)

    Yuen, H. P. H.

    1971-01-01

    Communication theory problems incorporating quantum effects for optical-frequency applications are discussed. Under suitable conditions, a unique quantum channel model corresponding to a given classical space-time varying linear random channel is established. A procedure is described by which a proper density-operator representation applicable to any receiver configuration can be constructed directly from the channel output field. Some examples illustrating the application of our methods to the development of optical quantum channel representations are given. Optimizations of communication system performance under different criteria are considered. In particular, certain necessary and sufficient conditions on the optimal detector in M-ary quantum signal detection are derived. Some examples are presented. Parameter estimation and channel capacity are discussed briefly.

  12. DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC.

    Science.gov (United States)

    The Filter Flow Technology, Inc. (FFT) Colloid Polishing Filter Method (CPFM) was tested as a transportable, trailer mounted, system that uses sorption and chemical complexing phenomena to remove heavy metals and nontritium radionuclides from water. Contaminated waters can be pro...

  13. Does working with industry come at a price? A study of doctoral candidates’ performance in collaborative vs. non-collaborative Ph.D. projects

    NARCIS (Netherlands)

    Salimi, Negin; Bekkers, Rudi; Frenken, Koen

    2015-01-01

    Collaborative Ph.D. projects between university and industry constitute an important aspect of university–industry collaboration, yet has remained under-researched thus far. The specific question this paper asks is how collaborative Ph.D. projects perform compared to non-collaborative Ph.D. projects

  14. Design and development of high performance panel air filter with experimental evaluation and analysis of filter media pleats

    Directory of Open Access Journals (Sweden)

    Sagar R. Patil

    2015-11-01

    Full Text Available In automobile vehicles mostly plastic molded panel filters used for the purpose of engine air filtration. Fibrous structured cellulose media were being used with different permeability’s according to requirement of rated air flow rate required for the engine. To optimize the filter pleat design of automotive panel air filter, it is important to study correlation of pressure drop, dust holding capacity & efficiency. The main role of a filter is to provide least pressure drop with high dust holding and efficiency. A channel made for the testing of different pleat designs. This research comprises of experimental design & evaluation of filter element with variable pleat depth and pleat density. This assessment offers the selection of pleat design according to the performance requirements.

  15. Digital Filters for Low Frequency Equalization

    DEFF Research Database (Denmark)

    Tyril, Marni; Abildgaard, J.; Rubak, Per

    2001-01-01

    Digital filters with high resolution in the low-frequency range are studied. Specifically, for a given computational power, traditional IIR filters are compared with warped FIR filters, warped IIR filters, and modified warped FIR filters termed warped individual z FIR filters (WizFIR). The results...... indicate that IIR filters are the most effective in a number of situations....

  16. Comparative Evaluation of Adaptive Filter and Neuro-Fuzzy Filter in Artifacts Removal From Electroencephalogram Signal

    Directory of Open Access Journals (Sweden)

    Paulchamy Balaiah

    2012-01-01

    when fine details are processed. Results: The computational result shows that the artifacts from the EEG are removed to a great extent and this has led to the accurate analysis and diagnosis of the EEG related diseases. Conclusion: Experimental results show that the proposed neuro-fuzzy technique is very effective and performs significantly better. The fidelity of the reconstructed EEG signal is assessed quantitatively using parameters such as Signal to Noise Ratio (SNR and Power Spectral Density (PSD. In addition we have also compared the performance of adaptive filter and neuro-fuzzy filter based on the above parameters.

  17. PHD1 links cell-cycle progression to oxygen sensing through hydroxylation of the centrosomal protein Cep192.

    Science.gov (United States)

    Moser, Sandra C; Bensaddek, Dalila; Ortmann, Brian; Maure, Jean-Francois; Mudie, Sharon; Blow, J Julian; Lamond, Angus I; Swedlow, Jason R; Rocha, Sonia

    2013-08-26

    PHD1 belongs to the family of prolyl-4-hydroxylases (PHDs) that is responsible for posttranslational modification of prolines on specific target proteins. Because PHD activity is sensitive to oxygen levels and certain byproducts of the tricarboxylic acid cycle, PHDs act as sensors of the cell's metabolic state. Here, we identify PHD1 as a critical molecular link between oxygen sensing and cell-cycle control. We show that PHD1 function is required for centrosome duplication and maturation through modification of the critical centrosome component Cep192. Importantly, PHD1 is also required for primary cilia formation. Cep192 is hydroxylated by PHD1 on proline residue 1717. This hydroxylation is required for binding of the E3 ubiquitin ligase SCF(Skp2), which ubiquitinates Cep192, targeting it for proteasomal degradation. By modulating Cep192 levels, PHD1 thereby affects the processes of centriole duplication and centrosome maturation and contributes to the regulation of cell-cycle progression. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  18. The status of PhD education in economic, social, and administrative sciences between 2005 and 2008.

    Science.gov (United States)

    Farley, Joel F; Wang, Chi-Chuan; Blalock, Susan J

    2010-09-10

    To describe the funding, education, enrollment, and graduation patterns from economic, social, and administrative sciences PhD programs in colleges and schools of pharmacy in the United States. Economic, social, and administrative sciences PhD programs were identified from the American Association of Colleges of Pharmacy (AACP) Web site. A 41-item online survey instrument was sent to the director of graduate studies of each identified program. Only programs offering a PhD degree were included in the study. Of the 26 programs surveyed, 20 (77%) provided useable responses to the survey instrument. Approximately 91% of PhD programs guarantee funding to incoming students with an average commitment of 2.9 years. On average, students were paid a stipend of $18,000 per year for commitments to research and teaching assistantships, each averaging approximately 2 years in length. Programs admitted an average of 3.5 students per year and graduated approximately 85% of entering students. The majority of students are non-US citizens and accept positions in either academic or industrial positions after graduation. Most economic, social, and administrative sciences PhD programs guarantee funding to incoming PhD candidates. Programs offering funding packages significantly below the average may be at a competitive disadvantage. It is unclear whether the number of students graduating from PhD programs is adequate to fulfill academic and industrial needs.

  19. Substrate preference of the HIF-prolyl hydroxylase-2 (PHD2) and substrate-induced conformational change.

    Science.gov (United States)

    Pektas, Serap; Knapp, Michael J

    2013-09-01

    HIF prolyl-4-hydroxylase 2 (PHD2) is a non-heme Fe, 2-oxoglutarate (2OG) dependent dioxygenase that regulates the hypoxia inducible transcription factor (HIF) by hydroxylating two conserved prolyl residues in N-terminal oxygen degradation domain (NODD) and C-terminal oxygen degradation domain (CODD) of HIF-1α. Prior studies have suggested that the substrate preference of PHD2 arises from binding contacts with the β2β3 loop of PHD2. In this study we tested the substrate selectivity of PHD2 by kinetic competition assays, varied ionic strength, and global protein flexibility using amide H/D exchange (HDX). Our results revealed that PHD2 preferred CODD by 20-fold over NODD and that electrostatics influenced this effect. Global HDX monitored by mass spectrometry indicated that binding of Fe(II) and 2OG stabilized the overall protein structure but the saturating concentrations of either NODD or CODD caused an identical change in protein flexibility. These observations imply that both substrates stabilize the β2β3 loop to the same extent. Under unsaturated substrate conditions NODD led to a higher HDX rate than CODD due to its lower binding affinity to PHD2. Our results suggest that loop closure is the dominant contributor to substrate selectivity in PHD2.

  20. Development of DWDM Filter Manufacture

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    DWDM technology is developing rapidly. Thin film narrow bandpass filter plays an important role in this field. This article presents some achievements in developing the DWDM narrow bandpass filters and also describes the results achieved by us.

  1. Research on the Comparison Analyses of Three-Phase Discrete and Integrated LC Filters in Three-Phase PV Inverter

    Directory of Open Access Journals (Sweden)

    Ying Jiang

    2013-01-01

    Full Text Available In three-phase photovoltaic (PV system, three-phase filter inductors are important part for the output electrical power quality. The comparison analyses of three-phase discrete filter inductors and two kinds of three-phase integrated filter inductors in three-phase PV inverter are proposed. Firstly, the three-phase PV inverter operation with discrete filter inductors is analyzed, and the design of discrete filter inductors is given; then operation of the three-phase PV inverter with three-phase integrated five-limb magnetic core filter inductors is analyzed, the design of integrated filter inductors with five-limb magnetic core is given, then the operation of three-phase PV inverter with three-phase integrated three-limb magnetic core filter inductors is analyzed, and the design of integrated filter inductors with three limbs magnetic core is given. The conclusion of comparison between three-phase discrete filter inductors and two kinds of three-phase integrated filter inductors is done; it means that the three-phase discrete filter inductors can achieve better output electrical power quality with lower power density and three-phase integrated filter inductors can achieve higher power density with lower output electrical power quality. Finally, the experiment results are given to compare the volume and filter effect of three kinds of filter inductors in three-phase PV inverter.

  2. Spark Ignition of Monodisperse Fuel Sprays. Ph.D. Thesis

    Science.gov (United States)

    Danis, Allen M.; Cernansky, Nicholas P.; Namer, Izak

    1987-01-01

    A study of spark ignition energy requirements was conducted with a monodisperse spray system allowing independent control of droplet size, equivalent ratio, and fuel type. Minimum ignition energies were measured for n-heptane and methanol sprays characterized at the spark gap in terms of droplet diameter, equivalence ratio (number density) and extent of prevaporization. In addition to sprays, minimum ignition energies were measured for completely prevaporized mixtures of the same fuels over a range of equivalence ratios to provide data at the lower limit of droplet size. Results showed that spray ignition was enhanced with decreasing droplet size and increasing equivalence ratio over the ranges of the parameters studied. By comparing spray and prevaporized ignition results, the existence of an optimum droplet size for ignition was indicated for both fuels. Fuel volatility was seen to be a critical factor in spray ignition. The spray ignition results were analyzed using two different empirical ignition models for quiescent mixtures. Both models accurately predicted the experimental ignition energies for the majority of the spray conditions. Spray ignition was observed to be probabilistic in nature, and ignition was quantified in terms of an ignition frequency for a given spark energy. A model was developed to predict ignition frequencies based on the variation in spark energy and equivalence ratio in the spark gap. The resulting ignition frequency simulations were nearly identical to the experimentally observed values.

  3. Deterministic Mean-Field Ensemble Kalman Filtering

    KAUST Repository

    Law, Kody J. H.

    2016-05-03

    The proof of convergence of the standard ensemble Kalman filter (EnKF) from Le Gland, Monbet, and Tran [Large sample asymptotics for the ensemble Kalman filter, in The Oxford Handbook of Nonlinear Filtering, Oxford University Press, Oxford, UK, 2011, pp. 598--631] is extended to non-Gaussian state-space models. A density-based deterministic approximation of the mean-field limit EnKF (DMFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence k between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for dimension d<2k. The fidelity of approximation of the true distribution is also established using an extension of the total variation metric to random measures. This is limited by a Gaussian bias term arising from nonlinearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

  4. Selection of noise parameters for Kalman filter

    Institute of Scientific and Technical Information of China (English)

    Ka-Veng Yuen; Ka-In Hoi; Kai-Meng Mok

    2007-01-01

    The Bayesian probabilistic approach is proposed to estimate the process noise and measurement noise parameters for a Kalman filter. With state vectors and covariance matrices estimated by the Kalman filter, the likehood of the measurements can be constructed as a function of the process noise and measurement noise parameters. By maximizing the likklihood function with respect to these noise parameters, the optimal values can be obtained. Furthermore, the Bayesian probabilistic approach allows the associated uncertainty to be quantified. Examples using a single-degree-of-freedom system and a ten-story building illustrate the proposed method. The effect on the performance of the Kalman filter due to the selection of the process noise and measurement noise parameters was demonstrated. The optimal values of the noise parameters were found to be close to the actual values in the sense that the actual parameters were in the region with significant probability density. Through these examples, the Bayesian approach was shown to have the capability to provide accurate estimates of the noise parameters of the Kalman filter, and hence for state estimation.

  5. Optical filters inhibiting television-induced photosensitive seizures.

    Science.gov (United States)

    Takahashi, Y; Sato, T; Goto, K; Fujino, M; Fujiwara, T; Yamaga, M; Ito, T; Isono, H; Kondo, N

    2001-11-27

    Televised images are the most common stimulus for provoking photosensitive seizures in photosensitive persons. To inhibit photosensitive seizures in photosensitive persons who do or do not have epilepsy, the authors sought nonpharmacologic methods for reducing the levels of photic stimulation of televised images. The authors found two types of pathophysiologic mechanisms (wavelength-dependent and quantity of light-dependent mechanisms) for photoparoxysmal responses (PPR). The authors tested two different types of optical filters, one reflecting long-wavelength red light selectively, which stimulates a wavelength-dependent mechanism, and the other absorbing light in the visible spectrum evenly (neutral density filters). Inhibiting effects of optical filters were studied by conventional intermittent photic stimulation (IPS) using strobe light and novel photic stimulation using flashing cathode ray tubes (CRT). Both filters individually inhibited PPR insufficiently (less than 50%). Compound optical filters, composed of both types of filters, can inhibit the PPR, approximately 90% for IPS and 95% for photic stimulation with CRT. These compound optical filters do not destroy chromaticity of emissions from the television's CRT. These compound filters may be useful to prevent seizures induced by television in photosensitive persons.

  6. The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

    Directory of Open Access Journals (Sweden)

    Karlsson Rickard

    2010-01-01

    Full Text Available For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF. This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

  7. Assessment of ceramic membrane filters

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R.K.; Geyer, H.K.; Im, K.H. [and others

    1995-08-01

    The objectives of this project include the development of analytical models for evaluating the fluid mechanics of membrane coated, dead-end ceramic filters, and to determine the effects of thermal and thermo-chemical aging on the material properties of emerging ceramic hot gas filters. A honeycomb cordierite monolith with a thin ceramic coating and a rigid candle filter were evaluated.

  8. Multilevel particle filter

    KAUST Repository

    Law, Kody

    2016-01-06

    This talk will pertain to the filtering of partially observed diffusions, with discrete-time observations. It is assumed that only biased approximations of the diffusion can be obtained, for choice of an accuracy parameter indexed by l. A multilevel estimator is proposed, consisting of a telescopic sum of increment estimators associated to the successive levels. The work associated to O( 2) mean-square error between the multilevel estimator and average with respect to the filtering distribution is shown to scale optimally, for example as O( 2) for optimal rates of convergence of the underlying diffusion approximation. The method is illustrated on some toy examples as well as estimation of interest rate based on real S&P 500 stock price data.

  9. Filtered cathodic arc source

    Science.gov (United States)

    Falabella, Steven; Sanders, David M.

    1994-01-01

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  10. Event Filter Dataflow Software

    CERN Document Server

    Meessen, C; Bosman, M; Karr, K M; Pacheco, A; Qian, Z; Touchard, F

    2000-01-01

    This document describes the software handling the flow of events through the Event Filter. This is the fourth iteration of the implementation of the code. When compared to previous versions, enhancements come from the feedback by users and can be seen as simplifications while the interfaces have been kept identical. The high level design of the dataflow is briefly reminded. Then, the details of the implementation of the components are given.

  11. Web Content Filtering

    OpenAIRE

    Gómez Hidalgo, José María; Puertas Sanz, Enrique; Carrero García, Francisco Manuel; Buenaga Rodríguez, Manuel de

    2009-01-01

    Across the years, Internet has evolved from an academic network to a truly communication medium, reaching impressive levels of audience and becoming a billionaire business. Many of our working, studying, and entertainment activities are nowadays overwhelmingly limited if we get disconnected from the net of networks. And of course, with the use comes abuse. The World Wide Web features a wide variety of content that are harmful for children or just inappropriate in the workplace. Web filtering ...

  12. Archimedes Mass Filter Vaporizer

    Science.gov (United States)

    Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

    2001-10-01

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

  13. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequat...... predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling....

  14. Interactions between seagrass complexity, hydrodynamic flow and biomixing alter food availability for associated filter-feeding organisms.

    Directory of Open Access Journals (Sweden)

    Vanessa González-Ortiz

    Full Text Available Seagrass shoots interact with hydrodynamic forces and thereby a positively or negatively influence the survival of associated species. The modification of these forces indirectly alters the physical transport and flux of edible particles within seagrass meadows, which will influence the growth and survivorship of associated filter-feeding organisms. The present work contributes to gaining insight into the mechanisms controlling the availability of resources for filter feeders inhabiting seagrass canopies, both from physical (influenced by seagrass density and patchiness and biological (regulated by filter feeder density perspectives. A factorial experiment was conducted in a large racetrack flume, which combined changes in hydrodynamic conditions, chlorophyll a concentration in the water and food intake rate (FIR in a model active filter-feeding organism (the cockle. Results showed that seagrass density and patchiness modified both hydrodynamic forces and availability of resources for filter feeders. Chlorophyll a water content decreased to 50% of the initial value when densities of both seagrass shoots and cockles were high. Also, filter feeder density controlled resource availability within seagrass patches, depending on its spatial position within the racetrack flume. Under high density of filter-feeding organisms, chlorophyll a levels were lower between patches. This suggests that the pumping activity of cockles (i.e. biomixing is an emergent key factor affecting both resource availability and FIR for filter feeders in dense canopies. Applying our results to natural conditions, we suggest the existence of a direct correlation between habitat complexity (i.e. shoot density and degree of patchiness and filter feeders density. Fragmented and low-density patches seem to offer both greater protection from hydrodynamic forces and higher resource availability. In denser patches, however, resources are allocated mostly within the canopy, which would

  15. Interactions between seagrass complexity, hydrodynamic flow and biomixing alter food availability for associated filter-feeding organisms.

    Science.gov (United States)

    González-Ortiz, Vanessa; Egea, Luis G; Jiménez-Ramos, Rocio; Moreno-Marín, Francisco; Pérez-Lloréns, José L; Bouma, Tjeed J; Brun, Fernando G

    2014-01-01

    Seagrass shoots interact with hydrodynamic forces and thereby a positively or negatively influence the survival of associated species. The modification of these forces indirectly alters the physical transport and flux of edible particles within seagrass meadows, which will influence the growth and survivorship of associated filter-feeding organisms. The present work contributes to gaining insight into the mechanisms controlling the availability of resources for filter feeders inhabiting seagrass canopies, both from physical (influenced by seagrass density and patchiness) and biological (regulated by filter feeder density) perspectives. A factorial experiment was conducted in a large racetrack flume, which combined changes in hydrodynamic conditions, chlorophyll a concentration in the water and food intake rate (FIR) in a model active filter-feeding organism (the cockle). Results showed that seagrass density and patchiness modified both hydrodynamic forces and availability of resources for filter feeders. Chlorophyll a water content decreased to 50% of the initial value when densities of both seagrass shoots and cockles were high. Also, filter feeder density controlled resource availability within seagrass patches, depending on its spatial position within the racetrack flume. Under high density of filter-feeding organisms, chlorophyll a levels were lower between patches. This suggests that the pumping activity of cockles (i.e. biomixing) is an emergent key factor affecting both resource availability and FIR for filter feeders in dense canopies. Applying our results to natural conditions, we suggest the existence of a direct correlation between habitat complexity (i.e. shoot density and degree of patchiness) and filter feeders density. Fragmented and low-density patches seem to offer both greater protection from hydrodynamic forces and higher resource availability. In denser patches, however, resources are allocated mostly within the canopy, which would benefit

  16. Publication rate and PhD enrolment following a medical pre-graduate research programme

    DEFF Research Database (Denmark)

    Skovgaard, Marlene; Okkels, Niels; Christensen, Mette Krogh;

    2015-01-01

    INTRODUCTION: In the 1990s, the publication and PhD recruitment rates following the Danish pre-graduate research programme (PGRP) in medicine were 54% and 33%, respectively. Updated estimates are unknown. METHODS: All medical students enrolled in the PGRP at the Faculty of Medicine, Aarhus......, PGRP completion time and years in medical school at the time of PGRP initiation. Supervisors were described by sex, title, position and affiliation. Calculations were tested by the chi-squared test; p ...: Fast completion of the PGRP and early enrolment in the programme were associated with scientific publishing and PhD recruitment. The publication rate has remained stable over time. FUNDING: Authors were funded by their individual affiliations. TRIAL REGISTRATION: not relevant....

  17. Publication ethics from the perspective of PhD students of health sciences: a limited experience.

    Science.gov (United States)

    Arda, Berna

    2012-06-01

    Publication ethics, an important subtopic of science ethics, deals with determination of the misconducts of science in performing research or in the dissemination of ideas, data and products. Science, the main features of which are secure, reliable and ethically obtained data, plays a major role in shaping the society. As long as science maintains its quality by being based on reliable and ethically obtained data, it will be possible to maintain its role in shaping the society. This article is devoted to the presentation of opinions of PhD candidate students in health sciences in Ankara concerning publication ethics. The data obtained from 143 PhD students from the fields of medicine, dentistry, pharmacy and veterinary reveal limited but unique experiences. It also shows that plagiarism is one of the worst issues in the publication ethics from the perspective of these young academics.

  18. The use of a Virtual Community to Complement the MS PHD'S Professional Development Program

    Science.gov (United States)

    Nieves, I. U.; Brown, D. C.; Bailey, K.; Easley, R.; Johnson, A.; Ithier, W.; Powell, J. M.; Whitney, V. W.; Pyrtle, A. J.

    2005-12-01

    The aim of the Minorities Striving and Pursuing Higher Degrees of Success in Earth System Sciencer Professional Development Program (MS PHD'S PDP) is to provide professional and mentoring experiences that facilitate the advancement of minorities committed to achieving outstanding Earth system science and engineering careers. The MS PHD'S PDP is structured in three phases that are connected by engagement in virtual community building activities, allowing for continuous peer to peer and mentor to mentee interactions. These activities occur through the use of the MSPHD'S website forum and web cam dialogues. In addition, the virtual community provides the personal and professional support necessary to ensure the success of the students. Examples of interactions within the MSPHD'S PDP virtual community will be presented.

  19. Examining the British PhD viva: opening new doors or scarring for life?

    Science.gov (United States)

    Carter, Bernie; Whittaker, Karen

    2009-01-01

    The PhD viva -- regardless of its format -- has the potential to be a significant rite of passage for the student. It is an experience that can resonate for months or years afterwards. Part of the challenge is that for everyone involved -- student, supervisory team and examiners -- a degree of end-point uncertainty exists. These ambiguities and tensions are perhaps an inherent part of any examination but are particularly characteristic of the examination of the individual and unique body of work that constitutes the doctoral thesis. In recent years, increased attention has been placed on the processes that surround the examination, aiming to increase transparency, consistency and fairness. However, the process of examining a student and their thesis remains challenging and is surrounded by different agendas, ideologies and practices. This paper examines some of the issues surrounding the PhD viva, primarily focusing on the British viva whilst weaving in commentary about the Australian system.

  20. Protein interactions of the MLL PHD fingers modulate MLL target gene regulation in human cells.

    Science.gov (United States)

    Fair, K; Anderson, M; Bulanova, E; Mi, H; Tropschug, M; Diaz, M O

    2001-05-01

    The PHD fingers of the human MLL and Drosophila trx proteins have strong amino acid sequence conservation but their function is unknown. We have determined that these fingers mediate homodimerization and binding of MLL to Cyp33, a nuclear cyclophilin. These two proteins interact in vitro and in vivo in mammalian cells and colocalize at specific nuclear subdomains. Overexpression of the Cyp33 protein in leukemia cells results in altered expression of HOX genes that are targets for regulation by MLL. These alterations are suppressed by cyclosporine and are not observed in cell lines that express a mutant MLL protein without PHD fingers. These results suggest that binding of Cyp33 to MLL modulates its effects on the expression of target genes.

  1. Publication rate and PhD enrolment following a medical pre-graduate research programme

    DEFF Research Database (Denmark)

    Skovgaard, Marlene; Okkels, Niels; Christensen, Mette Krogh;

    2015-01-01

    INTRODUCTION: In the 1990s, the publication and PhD recruitment rates following the Danish pre-graduate research programme (PGRP) in medicine were 54% and 33%, respectively. Updated estimates are unknown. METHODS: All medical students enrolled in the PGRP at the Faculty of Medicine, Aarhus......% of the overall 224 papers, and 90% were original articles. Publication was positively associated with completion of the PGRP in related to enrolment in the PGRP after fewer years in medical school. CONCLUSIONS......: Fast completion of the PGRP and early enrolment in the programme were associated with scientific publishing and PhD recruitment. The publication rate has remained stable over time. FUNDING: Authors were funded by their individual affiliations. TRIAL REGISTRATION: not relevant....

  2. The training, careers, and work of Ph.D. physical scientists: Not simply academic

    Science.gov (United States)

    Smith, Steven J.; Pedersen-Gallegos, Liane; Riegle-Crumb, Catherine

    2002-11-01

    We present an in-depth portrait of the training, careers, and work of recent Ph.D. physical scientists. Use of specialized training varies widely, with about half often using knowledge of their Ph.D. specialty area in their jobs. The use of specialized training does not, however, correlate with job satisfaction. In this and other important measures, there are relatively few differences between "academics" and "nonacademics." Important job skills for all employment sectors include writing, oral presentation, management, data analysis, designing projects, critical thinking, and working in an interdisciplinary context. Rankings given by respondents of graduate training in some of these skill areas were significantly lower than the importance of these skills in the workplace. We also found that the rated quality of graduate training varies relatively little by department or advisor. Finally, although nonacademic aspirations among graduate students are fairly common, these do not appear to be well supported while in graduate school.

  3. Phd study of reliability and validity: One step closer to a standardized music therapy assessment model

    DEFF Research Database (Denmark)

    Jacobsen, Stine Lindahl

    The paper will present a phd study concerning reliability and validity of music therapy assessment model “Assessment of Parenting Competences” (APC) in the area of families with emotionally neglected children. This study had a multiple strategy design with a philosophical base of critical realism...... and pragmatism. The fixed design for this study was a between and within groups design in testing the APCs reliability and validity. The two different groups were parents with neglected children and parents with non-neglected children. The flexible design had a multiple case study strategy specifically...... of the theoretical understanding of the clientgroup. Furthermore, a short describtion of the specific assessment protocol and analysis procedures of APC will be a part of the presentation. The phd study sought to explore how to develop measures of parenting competences in looking at autonomy relationship...

  4. Adaptive filters for color image processing

    Directory of Open Access Journals (Sweden)

    Papanikolaou V.

    1998-01-01

    Full Text Available The color filters that are used to attenuate noise are usually optimized to perform extremely well when dealing with certain noise distributions. Unfortunately it is often the case that the noise corrupting the image is not known. It is thus beneficial to know a priori the type of noise corrupting the image in order to select the optimal filter. A method of extracting and characterizing the noise within a digital color image using the generalized Gaussian probability density function (pdf (B.D. Jeffs and W.H. Pun, IEEE Transactions on Image Processing, 4(10, 1451–1456, 1995 and Proceedings of the Int. Conference on Image Processing, 465–468, 1996, is presented. In this paper simulation results are included to demonstrate the effectiveness of the proposed methodology.

  5. Adaptive filters for color image processing

    Directory of Open Access Journals (Sweden)

    V. Papanikolaou

    1999-01-01

    Full Text Available The color filters that are used to attenuate noise are usually optimized to perform extremely well when dealing with certain noise distributions. Unfortunately it is often the case that the noise corrupting the image is not known. It is thus beneficial to know a priori the type of noise corrupting the image in order to select the optimal filter. A method of extracting and characterizing the noise within a digital color image using the generalized Gaussian probability density function (pdf (B.D. Jeffs and W.H. Pun, IEEE Transactions on Image Processing, 4(10, 1451–1456, 1995 and Proceedings of the Int. Conference on Image Processing, 465–468, 1996, is presented. In this paper simulation results are included to demonstrate the effectiveness of the proposed methodology.

  6. Bucharest PhD Training School : Modern Aspects of Quantum Field Theory and Applications

    CERN Document Server

    2015-01-01

    Bucharest 2015 – Modern Aspects of Quantum Field Theory is part of the CERN – SEENET-MTP PhD Training Program, which consists of a number of seminars in theoretical high energy Physics. This is the second seminar organized by this Program. Here are some photos from this event held in Bucharest between 8-14 November 2015. The previous seminar was organized in Belgrade, under the name Belgrade 2015 - Supergravity.

  7. News from TRI’s Country Networks of PhD Theses Writers

    Directory of Open Access Journals (Sweden)

    Alex P. Schmid

    2014-06-01

    Full Text Available The Terrorism Research Initiative (TRI seeks to improve the quality of research on terrorism and counter-terrorism as well as related research on political violence and armed conflict. One instrument is TRI’s annual award for the best doctoral dissertation in this field. Another is the maintenance of national or regional networks of post-graduate students working on their PhD theses.

  8. Including systematic reviews in PhD programmes and candidatures in nursing - 'Hobson's choice'?

    Science.gov (United States)

    Olsson, Cecilia; Ringnér, Anders; Borglin, Gunilla

    2014-03-01

    Nowadays, gathering and synthesising evidence, i.e. conducting systematic reviews, is considered an important part of any health service research endeavour. Reviewing the literature, however suggest that it is not yet common that PhD students/doctoral candidates publish systematic reviews or even include a high quality review of the literature as a part of their PhD programme or candidature. Implying that systematic reviewing skills might not be acquired by going through an education on a postgraduate level. Additionally, scholars debating systematic reviews 'to be or not to be' as a part of research training seem to be sparse, especially within the field of nursing. In this issue for debate, we would like to propose that the absence of systematic reviews' in this context might severely hamper the 'up and coming' researchers as well as the research conducted. We envisage that this lack can have a negative impact on international nursing practice, and therefore propose that systematic reviews should be considered, whenever appropriate, as a mandatory part of any PhD programme or candidature. We believe that abilities in systematic reviewing will be a sought after research skills in the near future. Including systematic reviews would promote i) refined, well-grounded adequate research questions, ii) PhDs with broad and elevated methodological skills, iii) an increased level of evidence based nursing praxis. However, to make this a reality, supervisors, PhD students, and candidates would need to understand the value of this kind of research activity. Finally, lobbying University faculty boards and grant providers that are not inclined to view literature reviews as 'proper' research or as an important part of health service research, needs to be put on the agenda.

  9. PHD fingers in human diseases: Disorders arising from misinterpreting epigenetic marks

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Lindsey A. [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States); Allis, C. David [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States)], E-mail: alliscd@rockefeller.edu; Wang, Gang G. [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States)], E-mail: gwang@rockefeller.edu

    2008-12-01

    Histone covalent modifications regulate many, if not all, DNA-templated processes, including gene expression and DNA damage response. The biological consequences of histone modifications are mediated partially by evolutionarily conserved 'reader/effector' modules that bind to histone marks in a modification- and context-specific fashion and subsequently enact chromatin changes or recruit other proteins to do so. Recently, the Plant Homeodomain (PHD) finger has emerged as a class of specialized 'reader' modules that, in some instances, recognize the methylation status of histone lysine residues, such as histone H3 lysine 4 (H3K4). While mutations in catalytic enzymes that mediate the addition or removal of histone modifications (i.e., 'writers' and 'erasers') are already known to be involved in various human diseases, mutations in the modification-specific 'reader' proteins are only beginning to be recognized as contributing to human diseases. For instance, point mutations, deletions or chromosomal translocations that target PHD fingers encoded by many genes (such as recombination activating gene 2 (RAG2), Inhibitor of Growth (ING), nuclear receptor-binding SET domain-containing 1 (NSD1) and Alpha Thalassaemia and Mental Retardation Syndrome, X-linked (ATRX)) have been associated with a wide range of human pathologies including immunological disorders, cancers, and neurological diseases. In this review, we will discuss the structural features of PHD fingers as well as the diseases for which direct mutation or dysregulation of the PHD finger has been reported. We propose that misinterpretation of the epigenetic marks may serve as a general mechanism for human diseases of this category. Determining the regulatory roles of histone covalent modifications in the context of human disease will allow for a more thorough understanding of normal and pathological development, and may provide innovative therapeutic strategies

  10. "PhD Comics" author Jorge Cham on the power of procrastination

    CERN Document Server

    Stefania Pandolfi

    2015-01-01

    From Tuesday, 22 to Friday, 25 September, Jorge Cham visited CERN. The PHD Movie 2 was screened in the Main Auditorium  and the cartoonist also took part in one of the Researchers' Night events.    Jorge Cham in the CERN Control Centre. On the first day, the author of the comic strip Piled Higher and Deeper (PhD Comics) visited the CERN Control Centre, the Synchrocyclotron, the CMS Service Cavern and the ATLAS control room. On Thursday, he had a busy afternoon, starting with signing copies of his books and then giving a talk entitled “The Power of Procrastination” in a packed Main Auditorium. He made the audience laugh by narrating his experience as a graduate student in robotics at Stanford University, recounting how he started drawing PhD Comics and how it rapidly became popular in universities all over the world. He then analysed the frustrations and anxieties commonly experienced by any graduate student, causing...

  11. Management of Stress and Anxiety Among PhD Students During Thesis Writing: A Qualitative Study.

    Science.gov (United States)

    Bazrafkan, Leila; Shokrpour, Nasrin; Yousefi, Alireza; Yamani, Nikoo

    2016-01-01

    Today, postgraduate students experience a variety of stresses and anxiety in different situations of academic cycle. Stress and anxiety have been defined as a syndrome shown by emotional exhaustion and reduced personal goal achievement. This article addresses the causes and different strategies of coping with this phenomena by PhD students at Iranian Universities of Medical Sciences. The study was conducted by a qualitative method using conventional content analysis approach. Through purposive sampling, 16 postgraduate medical sciences PhD students were selected on the basis of theoretical sampling. Data were gathered through semistructured interviews and field observations. Six hundred fifty-four initial codes were summarized and classified into 4 main categories and 11 subcategories on the thematic coding stage dependent on conceptual similarities and differences. The obtained codes were categorized under 4 themes including "thesis as a major source of stress," "supervisor relationship," "socioeconomic problem," and "coping with stress and anxiety." It was concluded that PhD students experience stress and anxiety from a variety of sources and apply different methods of coping in effective and ineffective ways. Purposeful supervision and guidance can reduce the cause of stress and anxiety; in addition, coping strategy must be in a thoughtful approach, as recommended in this study.

  12. A move-step analysis of the concluding chapters in computer science PhD theses

    Directory of Open Access Journals (Sweden)

    Carmen Soler-Monreal

    2016-11-01

    Full Text Available This paper describes how computer science doctoral writers construct the closing chapters of their PhD theses. The data are drawn from the chapters playing a concluding role of 48 PhD theses defended at the University of Glasgow from 2008 to 2014. The analysis applied a qualitative-quantitative approach. The titles of the concluding chapters of the theses were first examined and also their divisions into sections and sub-sections. Then the chapters were subjected to a move-step analysis: Move 1 (M1 “Revisiting the study”; Move 2 (M2 “Consolidating research space”; Move 3 (M3 “Proposing practical applications and implications”, Move 4 (M4 “Recommending future work” and Move 5 (M5 “Recapitulating the study”. The results revealed that most of the computer science PhD theses have one final concluding chapter with three main moves: M1, M2 and M4. The most frequent steps are “reviewing the work carried out” and “summarizing the specific work reported in every thesis chapter” in M1, “presenting results and contributions”, “answering the initial research questions or hypotheses”, and “making claims” in M2, and “acknowledging limitations” and “suggesting further research” in M4. Movestep patterns appear in recurrent cycles throughout the concluding chapters. Several suggestions for pedagogical purposes are provided.

  13. Pioneering women in American mathematics the pre-1940 PhD's

    CERN Document Server

    Green, Judy

    2008-01-01

    More than 14 percent of the PhD's awarded in the United States during the first four decades of the twentieth century went to women, a proportion not achieved again until the 1980s. This book is the result of a study in which the authors identified all of the American women who earned PhD's in mathematics before 1940, and collected extensive biographical and bibliographical information about each of them. By reconstructing as complete a picture as possible of this group of women, Green and LaDuke reveal insights into the larger scientific and cultural communities in which they lived and worked. The book contains an extended introductory essay, as well as biographical entries for each of the 228 women in the study. The authors examine family backgrounds, education, careers, and other professional activities. They show that there were many more women earning PhD's in mathematics before 1940 than is commonly thought. Extended biographies and bibliographical information are available from the companion website fo...

  14. Research Career Persistence for Solar and Space Physics PhD

    Science.gov (United States)

    Moldwin, Mark B.; Morrow, Cherilynn

    2016-06-01

    Results from a recent graduate student survey found unsurprisingly that Solar and Space Physics (S&SP) PhD graduate students almost all aspire to have research careers in Solar and Space Physics. This study reports on the research career persistence over the first decade of the new millennium for S&SP PhDs. We used publication of science citation indexed articles as the indicator for persistence in a research career. We found that nearly two thirds (64%) of PhDs who graduated between 2001 and 2009 published refereed papers in 2012 or 2013, while 17% of PhDs never published another paper beyond the year they received their PhD. The remaining 19% of PhDs stopped publishing within three years of receiving their PhD. We found no gender difference between research persistence. We also found that though there is statistically no difference on persistence of publishing research between graduates of the largest programs compared to all other programs, there are significant differences between individual programs. This study indicates that a majority of S&SP PhDs find research careers but that a significant fraction pursue careers where publishing in science citation indexed journals is not required. Graduate programs, advisors, and potential graduate students can use these data for career planning and developing mentoring programs that meet the career outcomes of all of their graduates.

  15. Advancing Minorities and Women to the PhD in Physics and Astronomy

    Science.gov (United States)

    Stassun, Keivan

    2017-01-01

    We briefly review the current status of underrepresented minorities in physics and astronomy: The underrepresentation of Black-, Hispanic-, and Native-Americans is an order of magnitude problem. We then describe the Fisk-Vanderbilt Masters-to-PhD Bridge program as a successful model for addressing this problem. Since 2004 the program has admitted 110 students, 90% of them underrepresented minorities (50% female), with a retention rate of 90%. The program has become the top producer of African American master's degrees in physics, and is now one of the top producers of minority PhDs in astronomy, materials science, and physics. We summarize the main features of the program including its core strategies: (1) replacing the GRE in admissions with indicators that are better predictive of long-term success, (2) partnering with a minority-serving institution for student training through collaborative research, and (3) using the master's degree as a deliberate stepping stone to the PhD. We show how misuse of the GRE in graduate admissions may by itself in large part explain the ongoing underrepresentation of minorities in PhD programs, and we describe our alternate methods to identify talented individuals most likely to succeed. We describe our mentoring model and toolkit which may be utilized to enhance the success of all PhD students.

  16. Substrate-Trapped Interactors of PHD3 and FIH Cluster in Distinct Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Javier Rodriguez

    2016-03-01

    Full Text Available Amino acid hydroxylation is a post-translational modification that regulates intra- and inter-molecular protein-protein interactions. The modifications are regulated by a family of 2-oxoglutarate- (2OG dependent enzymes and, although the biochemistry is well understood, until now only a few substrates have been described for these enzymes. Using quantitative interaction proteomics, we screened for substrates of the proline hydroxylase PHD3 and the asparagine hydroxylase FIH, which regulate the HIF-mediated hypoxic response. We were able to identify hundreds of potential substrates. Enrichment analysis revealed that the potential substrates of both hydroxylases cluster in the same pathways but frequently modify different nodes of signaling networks. We confirm that two proteins identified in our screen, MAPK6 (Erk3 and RIPK4, are indeed hydroxylated in a FIH- or PHD3-dependent mechanism. We further determined that FIH-dependent hydroxylation regulates RIPK4-dependent Wnt signaling, and that PHD3-dependent hydroxylation of MAPK6 protects the protein from proteasomal degradation.

  17. ISO/IEEE 11073 PHD message generation toolkit to standardize healthcare device.

    Science.gov (United States)

    Lim, Joon-Ho; Park, Chanyong; Park, Soo-Jun; Lee, Kyu-Chul

    2011-01-01

    As senior population increases, various healthcare devices and services are developed such as fall detection device, home hypertension management service, and etc. However, to vitalize healthcare devices and services market, standardization for interoperability between device and service must precede. To achieve the standardization goal, the IEEE 11073 Personal Health Device (PHD) group has been standardized many healthcare devices, but until now there are few devices compatible with the PHD standard. One of main reasons is that it isn't easy for device manufactures to implement standard communication module by analyzing standard documents of over 600 pages. In this paper, we propose a standard message generation toolkit to easily standardize existing non-standard healthcare devices. The proposed toolkit generates standard PHD messages using inputted device information, and the generated messages are adapted to the device with the standard state machine file. For the experiments, we develop a reference H/W, and test the proposed toolkit with three healthcare devices: blood pressure, weighting scale, and glucose meter. The proposed toolkit has an advantage that even if the user doesn't know the standard in detail, the user can easily standardize the non-standard healthcare devices.

  18. Approximately liner phase IIR digital filter banks

    OpenAIRE

    J. D. Ćertić; M. D. Lutovac; L. D. Milić

    2013-01-01

    In this paper, uniform and nonuniform digital filter banks based on approximately linear phase IIR filters and frequency response masking technique (FRM) are presented. Both filter banks are realized as a connection of an interpolated half-band approximately linear phase IIR filter as a first stage of the FRM design and an appropriate number of masking filters. The masking filters are half-band IIR filters with an approximately linear phase. The resulting IIR filter banks are compared with li...

  19. The Pulsed High Density Experiment (PHDX) Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Slough, John P. [Univ. of Washington, Seattle, WA (United States); Andreason, Samuel [Univ. of Washington, Seattle, WA (United States)

    2017-04-27

    The purpose of this paper is to present the conclusions that can be drawn from the Field Reversed Configuration (FRC) formation experiments conducted on the Pulsed High Density experiment (PHD) at the University of Washington. The experiment is ongoing. The experimental goal for this first stage of PHD was to generate a stable, high flux (>10 mWb), high energy (>10 KJ) target FRC. Such results would be adequate as a starting point for several later experiments. This work focuses on experimental implementation and the results of the first four month run. Difficulties were encountered due to the initial on-axis plasma ionization source. Flux trapping with this ionization source acting alone was insufficient to accomplish experimental objectives. Additional ionization methods were utilized to overcome this difficulty. A more ideal plasma source layout is suggested and will be explored during a forthcoming work.

  20. PhD students' experiences of thesis supervision in Malaysia: managing relationships in the midst of institutional change

    National Research Council Canada - National Science Library

    Krauss, Steven Eric; Ismail, Ismi Arif

    2010-01-01

    Despite the plethora of studies that have been conducted on PhD supervision, little qualitative investigation has been conducted with a diverse, non-Western sample of doctoral students in an attempt...

  1. Design and use of guided mode resonance filters for refractive index sensing

    DEFF Research Database (Denmark)

    Hermannsson, Pétur Gordon

    This Ph.D. thesis is concerned with the design and use of guided mode resonance filters (GMRF) for applications in refractive index sensing. GMRFs are optical nanostructures capable of efficiently and resonantly reflecting a narrow wavelength interval of incident broad band light. They combine...... a diffractive element with a waveguiding element, and it is the coupling between diffracted light and quasi guided modes that gives rise to the resonant response. The linewidth of the resonance can be tuned by the material and geometrical configuration of the device. The resonance wavelength is highly sensitive...... to changes in refractive index that occur within the region overlapped by the quasi guided mode, and GMRFs are thus well suited for optical sensing and tunable filter applications. They produce a polarization dependent response and can be optically characterized in both reflection and transmission...

  2. Discovery and description of complete ammonium oxidizers in groundwater-fed rapid sand filters

    DEFF Research Database (Denmark)

    Palomo, Alejandro

    as biological filtration has long been acknowledged and recently been investigated. Biological filtration technology is widely used around the world and is especially important in Denmark as groundwater is the main source water for drinking water production. Because the groundwater has a relative high...... attention has been paid to the role of microorganisms in drinking water treatment technologies. In contrast, much effort has been devoted to eliminate potential pathogens in the drinking water treatment and supply systems. Nevertheless, the role of microbes in some drinking water treatments systems...... activity and roles in compound removal from the source water. This PhD project focused on a comprehensive investigation of the microbial communities in rapid sand filters beyond their purely taxonomical identification. For this purpose, samples collected from a rapid sand filter were subjected...

  3. Digital Filters for Low Frequency Equalization

    DEFF Research Database (Denmark)

    Tyril, Marni; Abildgaard, J.; Rubak, Per

    2001-01-01

    Digital filters with high resolution in the low-frequency range are studied. Specifically, for a given computational power, traditional IIR filters are compared with warped FIR filters, warped IIR filters, and modified warped FIR filters termed warped individual z FIR filters (WizFIR). The results...

  4. National, inter-institutional, graduate modules – blended learning approaches for PhD education in Ireland

    OpenAIRE

    Cosgrave, Michael; Murphy, Orla

    2012-01-01

    This paper is a case study that describes the design and delivery of national PhD lectures with 40 PhD candidates in Digital Arts and Humanities in Ireland simultaneously to four remote locations, in Trinity College Dublin, in University College Cork, in NUI Maynooth and NUI Galway. Blended learning approaches were utilized to augment traditional teaching practices combining: face-to-face engagement, video-conferencing to multiple sites, social media lecture delivery support – a live blog and...

  5. Advances in Collaborative Filtering

    Science.gov (United States)

    Koren, Yehuda; Bell, Robert

    The collaborative filtering (CF) approach to recommenders has recently enjoyed much interest and progress. The fact that it played a central role within the recently completed Netflix competition has contributed to its popularity. This chapter surveys the recent progress in the field. Matrix factorization techniques, which became a first choice for implementing CF, are described together with recent innovations. We also describe several extensions that bring competitive accuracy into neighborhood methods, which used to dominate the field. The chapter demonstrates how to utilize temporal models and implicit feedback to extend models accuracy. In passing, we include detailed descriptions of some the central methods developed for tackling the challenge of the Netflix Prize competition.

  6. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Hakon

    2016-06-14

    This work embeds a multilevel Monte Carlo sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF) in the setting of finite dimensional signal evolution and noisy discrete-time observations. The signal dynamics is assumed to be governed by a stochastic differential equation (SDE), and a hierarchy of time grids is introduced for multilevel numerical integration of that SDE. The resulting multilevel EnKF is proved to asymptotically outperform EnKF in terms of computational cost versus approximation accuracy. The theoretical results are illustrated numerically.

  7. Robust Kriged Kalman Filtering

    Energy Technology Data Exchange (ETDEWEB)

    Baingana, Brian; Dall' Anese, Emiliano; Mateos, Gonzalo; Giannakis, Georgios B.

    2015-11-11

    Although the kriged Kalman filter (KKF) has well-documented merits for prediction of spatial-temporal processes, its performance degrades in the presence of outliers due to anomalous events, or measurement equipment failures. This paper proposes a robust KKF model that explicitly accounts for presence of measurement outliers. Exploiting outlier sparsity, a novel l1-regularized estimator that jointly predicts the spatial-temporal process at unmonitored locations, while identifying measurement outliers is put forth. Numerical tests are conducted on a synthetic Internet protocol (IP) network, and real transformer load data. Test results corroborate the effectiveness of the novel estimator in joint spatial prediction and outlier identification.

  8. Charcoal filter testing

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J. [Nuclear Regulatory Commission, Washington, DC (United States)

    1997-08-01

    In this very brief, informal presentation, a representative of the US Nuclear Regulatory Commission outlines some problems with charcoal filter testing procedures and actions being taken to correct the problems. Two primary concerns are addressed: (1) the process to find the test method is confusing, and (2) the requirements of the reference test procedures result in condensation on the charcoal and causes the test to fail. To address these problems, emergency technical specifications were processed for three nuclear plants. A generic or an administrative letter is proposed as a more permanent solution. 1 fig.

  9. Biomedical Science Ph.D. Career Interest Patterns by Race/Ethnicity and Gender.

    Directory of Open Access Journals (Sweden)

    Kenneth D Gibbs

    Full Text Available Increasing biomedical workforce diversity remains a persistent challenge. Recent reports have shown that biomedical sciences (BMS graduate students become less interested in faculty careers as training progresses; however, it is unclear whether or how the career preferences of women and underrepresented minority (URM scientists change in manners distinct from their better-represented peers. We report results from a survey of 1500 recent American BMS Ph.D. graduates (including 276 URMs that examined career preferences over the course of their graduate training experiences. On average, scientists from all social backgrounds showed significantly decreased interest in faculty careers at research universities, and significantly increased interest in non-research careers at Ph.D. completion relative to entry. However, group differences emerged in overall levels of interest (at Ph.D. entry and completion, and the magnitude of change in interest in these careers. Multiple logistic regression showed that when controlling for career pathway interest at Ph.D. entry, first-author publication rate, faculty support, research self-efficacy, and graduate training experiences, differences in career pathway interest between social identity groups persisted. All groups were less likely than men from well-represented (WR racial/ethnic backgrounds to report high interest in faculty careers at research-intensive universities (URM men: OR 0.60, 95% CI: 0.36-0.98, p = 0.04; WR women: OR: 0.64, 95% CI: 0.47-0.89, p = 0.008; URM women: OR: 0.46, 95% CI: 0.30-0.71, p<0.001, and URM women were more likely than all other groups to report high interest in non-research careers (OR: 1.93, 95% CI: 1.28-2.90, p = 0.002. The persistence of disparities in the career interests of Ph.D. recipients suggests that a supply-side (or "pipeline" framing of biomedical workforce diversity challenges may limit the effectiveness of efforts to attract and retain the best and most

  10. Bowtie filters for dedicated breast CT: Analysis of bowtie filter material selection

    Energy Technology Data Exchange (ETDEWEB)

    Kontson, Kimberly, E-mail: Kimberly.Kontson@fda.hhs.gov; Jennings, Robert J. [Department of Bioengineering, University of Maryland, College Park, Maryland 20742 and Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)

    2015-09-15

    Purpose: For a given bowtie filter design, both the selection of material and the physical design control the energy fluence, and consequently the dose distribution, in the object. Using three previously described bowtie filter designs, the goal of this work is to demonstrate the effect that different materials have on the bowtie filter performance measures. Methods: Three bowtie filter designs that compensate for one or more aspects of the beam-modifying effects due to the differences in path length in a projection have been designed. The nature of the designs allows for their realization using a variety of materials. The designs were based on a phantom, 14 cm in diameter, composed of 40% fibroglandular and 60% adipose tissue. Bowtie design #1 is based on single material spectral matching and produces nearly uniform spectral shape for radiation incident upon the detector. Bowtie design #2 uses the idea of basis-material decomposition to produce the same spectral shape and intensity at the detector, using two different materials. With bowtie design #3, it is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Seven different materials were chosen to represent a range of chemical compositions and densities. After calculation of construction parameters for each bowtie filter design, a bowtie filter was created using each of these materials (assuming reasonable construction parameters were obtained), resulting in a total of 26 bowtie filters modeled analytically and in the PENELOPE Monte Carlo simulation environment. Using the analytical model of each bowtie filter, design profiles were obtained and energy fluence as a function of fan-angle was calculated. Projection images with and without each bowtie filter design were also generated using PENELOPE and reconstructed using FBP. Parameters such as dose distribution, noise uniformity

  11. From Microwave Filter to Digital Filter and Back Again

    DEFF Research Database (Denmark)

    Dalby, Arne Brejning

    1989-01-01

    A new very simple state variable flow graph representation for interdigital transmission line bandpass filters is presented, which has led to two important results: 1) A new type of digital filter with properties, that surpass the properties of most other (all pole) digital filtertypes. 2......) The study of the new digital filtertype has led to design formulas for interdigital transmission line filters that are very simple compared to the hitherto known formulas. The accuracy is the same or better....

  12. Filter and Filter Bank Design for Image Texture Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Randen, Trygve

    1997-12-31

    The relevance of this thesis to energy and environment lies in its application to remote sensing such as for instance sea floor mapping and seismic pattern recognition. The focus is on the design of two-dimensional filters for feature extraction, segmentation, and classification of digital images with textural content. The features are extracted by filtering with a linear filter and estimating the local energy in the filter response. The thesis gives a review covering broadly most previous approaches to texture feature extraction and continues with proposals of some new techniques. 143 refs., 59 figs., 7 tabs.

  13. Multiple object detection and tracking with pseudo-particle filter

    Institute of Scientific and Technical Information of China (English)

    Baolong GUO; Wei SUN

    2009-01-01

    To tackle the divergence of the classical particle filter method for multiple object tracking in image sequences, a new particle filter, called pseudoparticle filter (PPF), is proposed. The PPF invokes subset particles of generic particle filters to form a continuous estimate of the posterior density function of the objects.After sampling-importance resampling (SIR), the subset particles converge to the observations. It is proved that,using an appropriate kernel function of the mean shiift algorithm, we can get the subset particles of the observations and the fixed points of clustering results as the state of the objects. A multiple object data association and state estimation technique is proposed to resolve the subset particles correspondence ambiguities that arise when multiple objects are present. Experimental results demonstrate the efficiency and effectiveness of the algorithm for single and multiple object tracking.

  14. Distributed Particle Filter Implementation with Intermittent/Irregular Consensus Convergence

    CERN Document Server

    Mohammadi, Arash

    2011-01-01

    Motivated by non-linear, non-Gaussian, distributed multi-sensor/agent navigation and tracking applications, we propose a multi-rate consensus/fusion based framework for distributed implementation of the particle filter (CF/DPF). The CF/DPF framework is based on running localized particle filters to estimate the overall state vector at each observation node. Separate fusion filters are designed to consistently assimilate the local filtering distributions into the global posterior by compensating for the common past information between neighbouring nodes. The CF/DPF offers two distinct advantages over its counterparts. First, the CF/DPF framework is suitable for scenarios where network connectivity is intermittent and consensus can not be reached between two consecutive observations. Second, the CF/DPF is not limited to the Gaussian approximation for the global posterior density. A third contribution of the paper is the derivation of the optimal posterior Cram\\'er-Rao lower bound (PCRLB) for the distributed arc...

  15. Particle filtering in high-dimensional chaotic systems.

    Science.gov (United States)

    Lingala, Nishanth; Sri Namachchivaya, N; Perkowski, Nicolas; Yeong, Hoong C

    2012-12-01

    We present an efficient particle filtering algorithm for multiscale systems, which is adapted for simple atmospheric dynamics models that are inherently chaotic. Particle filters represent the posterior conditional distribution of the state variables by a collection of particles, which evolves and adapts recursively as new information becomes available. The difference between the estimated state and the true state of the system constitutes the error in specifying or forecasting the state, which is amplified in chaotic systems that have a number of positive Lyapunov exponents. In this paper, we propose a reduced-order particle filtering algorithm based on the homogenized multiscale filtering framework developed in Imkeller et al. "Dimensional reduction in nonlinear filtering: A homogenization approach," Ann. Appl. Probab. (to be published). In order to adapt the proposed algorithm to chaotic signals, importance sampling and control theoretic methods are employed for the construction of the proposal density for the particle filter. Finally, we apply the general homogenized particle filtering algorithm developed here to the Lorenz'96 [E. N. Lorenz, "Predictability: A problem partly solved," in Predictability of Weather and Climate, ECMWF, 2006 (ECMWF, 2006), pp. 40-58] atmospheric model that mimics mid-latitude atmospheric dynamics with microscopic convective processes.

  16. The effect of spectrally selective filters on visual search performance.

    Science.gov (United States)

    Chisum, G T; Sheehy, J B; Morway, P E; Askew, G K

    1987-05-01

    The effect of five spectrally selective filters on the performance of an acuity-dependent visual search task was evaluated. The filters were: A) a neutral density filter (control condition); B) a 5200A green interference filter; C) a 3215-250 red filter; D) a neodymium visor; and E) a holographic visor. The observers were presented with 5 blocks of 10 slides per filter. Each slide projected a 6 degrees X 6 degrees field of 900 letter O's--each 10' of arc--which contained a single Landolt C. The observers were required to find the C and indicate the position of the opening in the C. The opening in the C subtended 2.64' corresponding to an acuity of 0.38. Response time, error rate, accommodative accuracy, and the number and duration of fixations were recorded for each slide presentation. The results demonstrated that filter type had no effect on any of the response measures. During the first three trial blocks, the observers appeared to optimize their search strategies, after which they began to revert to their initial performance levels. However, this effect was not supported statistically.

  17. Nanoparticle optical notch filters

    Science.gov (United States)

    Kasinadhuni, Pradeep Kumar

    Developing novel light blocking products involves the design of a nanoparticle optical notch filter, working on the principle of localized surface plasmon resonance (LSPR). These light blocking products can be used in many applications. One such application is to naturally reduce migraine headaches and light sensitivity. Melanopsin ganglion cells present in the retina of the human eye, connect to the suprachiasmatic nucleus (SCN-the body's clock) in the brain, where they participate in the entrainment of the circadian rhythms. As the Melanopsin ganglion cells are involved in triggering the migraine headaches in photophobic patients, it is necessary to block the part of visible spectrum that activates these cells. It is observed from the action potential spectrum of the ganglion cells that they absorb light ranging from 450-500nm (blue-green part) of the visible spectrum with a λmax (peak sensitivity) of around 480nm (blue line). Currently prescribed for migraine patients is the FL-41 coating, which blocks a broad range of wavelengths, including wavelengths associated with melanopsin absorption. The nanoparticle optical notch filter is designed to block light only at 480nm, hence offering an effective prescription for the treatment of migraine headaches.

  18. Robust fault detection filter design

    Science.gov (United States)

    Douglas, Randal Kirk

    The detection filter is a specially tuned linear observer that forms the residual generation part of an analytical redundancy system designed for model-based fault detection and identification. The detection filter has an invariant state subspace structure that produces a residual with known and fixed directional characteristics in response to a known design fault direction. In addition to a parameterization of the detection filter gain, three methods are given for improving performance in the presence of system disturbances, sensor noise, model mismatch and sensitivity to small parameter variations. First, it is shown that by solving a modified algebraic Riccati equation, a stabilizing detection filter gain is found that bounds the H-infinity norm of the transfer matrix from system disturbances and sensor noise to the detection filter residual. Second, a specially chosen expanded-order detection filter is formed with fault detection properties identical to a set of independent reduced-order filters that have no structural constraints. This result is important to the practitioner because the difficult problem of finding a detection filter insensitive to disturbances and sensor noise is converted to the easier problem of finding a set of uncoupled noise insensitive filters. Furthermore, the statistical properties of the reduced-order filter residuals are easier to find than the statistical properties of the structurally constrained detection filter residual. Third, an interpretation of the detection filter as a special case of the dual of the restricted decoupling problem leads to a new detection filter eigenstructure assignment algorithm. The new algorithm places detection filter left eigenvectors, which annihilate the detection spaces, rather than right eigenvectors, which span the detection spaces. This allows for a more flexible observer based fault detection system structure that could not be formulated as a detection filter. Furthermore, the link to the dual

  19. Quantifying Monte Carlo uncertainty in ensemble Kalman filter

    Energy Technology Data Exchange (ETDEWEB)

    Thulin, Kristian; Naevdal, Geir; Skaug, Hans Julius; Aanonsen, Sigurd Ivar

    2009-01-15

    This report is presenting results obtained during Kristian Thulin PhD study, and is a slightly modified form of a paper submitted to SPE Journal. Kristian Thulin did most of his portion of the work while being a PhD student at CIPR, University of Bergen. The ensemble Kalman filter (EnKF) is currently considered one of the most promising methods for conditioning reservoir simulation models to production data. The EnKF is a sequential Monte Carlo method based on a low rank approximation of the system covariance matrix. The posterior probability distribution of model variables may be estimated fram the updated ensemble, but because of the low rank covariance approximation, the updated ensemble members become correlated samples from the posterior distribution. We suggest using multiple EnKF runs, each with smaller ensemble size to obtain truly independent samples from the posterior distribution. This allows a point-wise confidence interval for the posterior cumulative distribution function (CDF) to be constructed. We present a methodology for finding an optimal combination of ensemble batch size (n) and number of EnKF runs (m) while keeping the total number of ensemble members ( m x n) constant. The optimal combination of n and m is found through minimizing the integrated mean square error (MSE) for the CDFs and we choose to define an EnKF run with 10.000 ensemble members as having zero Monte Carlo error. The methodology is tested on a simplistic, synthetic 2D model, but should be applicable also to larger, more realistic models. (author). 12 refs., figs.,tabs

  20. Spatial filters for high average power lasers

    Science.gov (United States)

    Erlandson, Alvin C

    2012-11-27

    A spatial filter includes a first filter element and a second filter element overlapping with the first filter element. The first filter element includes a first pair of cylindrical lenses separated by a first distance. Each of the first pair of cylindrical lenses has a first focal length. The first filter element also includes a first slit filter positioned between the first pair of cylindrical lenses. The second filter element includes a second pair of cylindrical lenses separated by a second distance. Each of the second pair of cylindrical lenses has a second focal length. The second filter element also includes a second slit filter positioned between the second pair of cylindrical lenses.

  1. Reconfigurable Mixed Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    Neelofer Afzal

    2014-01-01

    Full Text Available This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

  2. Wavelength Filters in Fibre Optics

    CERN Document Server

    Venghaus, Herbert

    2006-01-01

    Wavelength filters constitute an essential element of fibre-optic networks. This book gives a comprehensive account of the principles and applications of such filters, including their technological realisation. After an introductory chapter on wavelength division multiplexing in current and future fibre optic networks follows a detailed treatment of the phase characteristics of wavelength filters, a factor frequently neglected but of significant importance at high bit rates. Subsequent chapters cover three-dimensional reflection of gratings, arrayed waveguide gratings, fibre Bragg gratings, Fabry-Perot filters, dielectric multilayer filters, ring filters, and interleavers. The book explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. It also includes in-depth information on the characteristics of both commercially available devices and those still at the R&D stage. All chapters are authored by inter...

  3. On robust kalman filtering with using wavelet analysis

    OpenAIRE

    Lobach, V. I.

    2013-01-01

    One presents a nonlinear filtering algorithm that propagates the entire condi- tional probability density functions. These functions are recursively computed in efficient manner using the discrete wavelet transform. With the multiresolution analysis we can speed up the computation by ignoring the high-frequency details of the probability density function up to a certain level. The level of the wavelet decomposition can be determined at each time step adaptively.

  4. Semi-Hausdorff Fuzzy Filters

    Directory of Open Access Journals (Sweden)

    V. Lakshmana Gomathi Nayagam

    2007-01-01

    Full Text Available The notion of fuzzy filters was studied by Vicente and Aranguren (1988, Lowen (1979, and Ramakrishnan and Nayagam (2002. The notion of fuzzily compactness was introduced and studied by Ramakrishnan and Nayagam (2002. In this paper, an equivalent condition of fuzzily compactness is studied and a new notion of semi-Hausdorffness on fuzzy filters, which cannot be defined in crisp theory of filters, is introduced and studied.

  5. Cuckoo Filter: Simplification and Analysis

    OpenAIRE

    Eppstein, David

    2016-01-01

    The cuckoo filter data structure of Fan, Andersen, Kaminsky, and Mitzenmacher (CoNEXT 2014) performs the same approximate set operations as a Bloom filter in less memory, with better locality of reference, and adds the ability to delete elements as well as to insert them. However, until now it has lacked theoretical guarantees on its performance. We describe a simplified version of the cuckoo filter using fewer hash function calls per query. With this simplification, we provide the first theo...

  6. Multi-filter spectrophotometry simulations

    Science.gov (United States)

    Callaghan, Kim A. S.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys.

  7. Faraday anomalous dispersion optical filters

    Science.gov (United States)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  8. Factors that facilitate or inhibit interest of domestic students in the engineering PhD: A mixed methods study

    Science.gov (United States)

    Howell Smith, Michelle C.

    Given the increasing complexity of technology in our society, the United States has a growing demand for a more highly educated technical workforce. Unfortunately, the proportion of United States citizens earning a PhD in engineering has been declining and there is concern about meeting the economic, national security and quality of life needs of our country. This mixed methods sequential exploratory instrument design study identified factors that facilitate or inhibit interest in engineering PhD programs among domestic engineering undergraduate students in the United States. This study developed a testable theory for how domestic students become interested in engineering PhD programs and a measure of that process, the Exploring Engineering Interest Inventory (EEII). The study was conducted in four phases. The first phase of the study was a qualitative grounded theory exploration of interest in the engineering PhD. Qualitative data were collected from domestic engineering students, engineering faculty and industry professional who had earned a PhD in engineering. The second phase, instrument development, developed the Exploring Engineering Interest Inventory (EEII), a measurement instrument designed with good psychometric properties to test a series of preliminary hypotheses related to the theory generated in the qualitative phase. In the third phase of the study, the EEII was used to collect data from a larger sample of junior and senior engineering majors. The fourth phase integrated the findings from the qualitative and quantitative phases. Four factors were identified as being significant influences of interest in the engineering PhD: Personal characteristics, educational environment, misperceptions of the economic and personal costs, and misperceptions of engineering work. Recommendations include increasing faculty encouragement of students to pursue an engineering PhD and programming to correct the misperceptions of the costs of the engineering PhD and the

  9. Filters and supports in orthoalgebras

    Science.gov (United States)

    Foulis, D. J.; Greechie, R. J.; Rüttimann, G. T.

    1992-05-01

    An orthoalgebra, which is a natural generalization of an orthomodular lattice or poset, may be viewed as a “logic” or “proposition system” and, under a welldefined set of circumstances, its elements may be classified according to the Aristotelian modalities: necessary, impossible, possible, and contingent. The necessary propositions band together to form a local filter, that is, a set that intersects every Boolean subalgebra in a filter. In this paper, we give a coherent account of the basic theory of Orthoalgebras, define and study filters, local filters, and associated structures, and prove a version of the compactness theorem in classical algebraic logic.

  10. Spatial filtering with photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maigyte, Lina [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Staliunas, Kestutis [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona 08010 (Spain)

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  11. Optimization of integrated polarization filters

    CERN Document Server

    Gagnon, Denis; Déziel, Jean-Luc; Dubé, Louis J

    2014-01-01

    This study reports on the design of small footprint, integrated polarization filters based on engineered photonic lattices. Using a rods-in-air lattice as a basis for a TE filter and a holes-in-slab lattice for the analogous TM filter, we are able to maximize the degree of polarization of the output beams up to 98 % with a transmission efficiency greater than 75 %. The proposed designs allow not only for logical polarization filtering, but can also be tailored to output an arbitrary transverse beam profile. The lattice configurations are found using a recently proposed parallel tabu search algorithm for combinatorial optimization problems in integrated photonics.

  12. Adaptive filtering and change detection

    CERN Document Server

    Gustafsson, Fredrik

    2003-01-01

    Adaptive filtering is a classical branch of digital signal processing (DSP). Industrial interest in adaptive filtering grows continuously with the increase in computer performance that allows ever more conplex algorithms to be run in real-time. Change detection is a type of adaptive filtering for non-stationary signals and is also the basic tool in fault detection and diagnosis. Often considered as separate subjects Adaptive Filtering and Change Detection bridges a gap in the literature with a unified treatment of these areas, emphasizing that change detection is a natural extensi

  13. Filter selection using genetic algorithms

    Science.gov (United States)

    Patel, Devesh

    1996-03-01

    Convolution operators act as matched filters for certain types of variations found in images and have been extensively used in the analysis of images. However, filtering through a bank of N filters generates N filtered images, consequently increasing the amount of data considerably. Moreover, not all these filters have the same discriminatory capabilities for the individual images, thus making the task of any classifier difficult. In this paper, we use genetic algorithms to select a subset of relevant filters. Genetic algorithms represent a class of adaptive search techniques where the processes are similar to natural selection of biological evolution. The steady state model (GENITOR) has been used in this paper. The reduction of filters improves the performance of the classifier (which in this paper is the multi-layer perceptron neural network) and furthermore reduces the computational requirement. In this study we use the Laws filters which were proposed for the analysis of texture images. Our aim is to recognize the different textures on the images using the reduced filter set.

  14. Kalman filtering implementation with Matlab

    OpenAIRE

    Kleinbauer, Rachel

    2004-01-01

    1960 und 1961 veröffentlichte Rudolf Emil Kalmen seine Arbeiten über einen rekursiven prädiktiven Filter, der auf dem Gebrauch von rekursiven Algorithmen basiert. Damit revolutionierte er das Feld der Schätzverfahren. Seitdem ist der sogenannte Kalman Filter Gegenstand ausführlicher Forschung und findet bis heute Anwendung in zahlreichen Gebieten. Der Kalman Filter schätzt den Zustand eines dynamischen Systems, auch wenn die exakte Form dieses Systems unbekannt ist. Der Filter ist sehr lei...

  15. The intractable cigarette 'filter problem'.

    Science.gov (United States)

    Harris, Bradford

    2011-05-01

    When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the 'filter problem'. These extensive filter research and development efforts suggest a phase of genuine optimism among cigarette designers that cigarette filters could be engineered to mitigate the health hazards of smoking. This paper explores the early history of cigarette filter research and development in order to elucidate why and when seemingly sincere filter engineering efforts devolved into manipulations in cigarette design to sustain cigarette marketing and mitigate consumers' concerns about the health consequences of smoking. Relevant word and phrase searches were conducted in the Legacy Tobacco Documents Library online database, Google Patents, and media and medical databases including ProQuest, JSTOR, Medline and PubMed. 13 tobacco industry documents were identified that track prominent developments involved in what the industry referred to as the 'filter problem'. These reveal a period of intense focus on the 'filter problem' that persisted from the mid-1950s to the mid-1960s, featuring collaborations between cigarette producers and large American chemical and textile companies to develop effective filters. In addition, the documents reveal how cigarette filter researchers' growing scientific knowledge of smoke chemistry led to increasing recognition that filters were unlikely to offer significant health protection. One of the primary concerns of cigarette producers was to design cigarette filters that could be economically incorporated into the massive scale of cigarette production. The synthetic plastic cellulose acetate

  16. The cholesterol-raising factor from boiled coffee does not pass a paper filter.

    NARCIS (Netherlands)

    Dusseldorp, van M.; Katan, M.B.; Vliet, van T.; Demacker, P.N.M.; Stalenhoef, A.F.H.

    1991-01-01

    Previous studies have indicated that consumption of boiled coffee raises total and low density lipoprotein (LDL) cholesterol, whereas drip-filtered coffee does not. We have tested the effect on serum lipids of consumed coffee that was first boiled and then filtered through commercial paper coffee

  17. Free Space Computation From Stochastic Occupancy Grids Based On Iconic Kalman Filtered Disparity Maps

    DEFF Research Database (Denmark)

    Høilund, Carsten; Moeslund, Thomas B.; Madsen, Claus B.;

    2010-01-01

    variance and increasing the density of the filtered disparity map. Then, a stochastic occupancy grid is calculated from the filtered disparity map, providing a top-down view of the scene where the uncertainty of disparity measurements are taken into account. These occupancy grids are segmented to indicate...

  18. The cholesterol-raising factor from boiled coffee does not pass a paper filter.

    NARCIS (Netherlands)

    Dusseldorp, van M.; Katan, M.B.; Vliet, van T.; Demacker, P.N.M.; Stalenhoef, A.F.H.

    1991-01-01

    Previous studies have indicated that consumption of boiled coffee raises total and low density lipoprotein (LDL) cholesterol, whereas drip-filtered coffee does not. We have tested the effect on serum lipids of consumed coffee that was first boiled and then filtered through commercial paper coffee fi

  19. Influence of operating parameters on cake formation in pilot scale pulse-jet bag filter.

    Science.gov (United States)

    Saleem, Mahmood; Krammer, Gernot; Khan, Rafi Ullah; Tahir, M Suleman

    2012-07-01

    Bag filters are commonly used for fine particles removal in off-gas purification. There dust laden gas pervades through permeable filter media starting at a lower pressure drop limit leaving dust (called filter cake) on the filter media. The filter cakeformation is influenced by many factors including filtration velocity, dust concentration, pressure drop limits, and filter media resistance. Effect of the stated parameters is investigated experimentally in a pilot scale pulse-jet bag filter test facility where lime stone dust is separated from air at ambient conditions. Results reveal that filtration velocity significantly affects filter pressure drop as well as cake properties; cake density and specific cake resistance. Cake density is slightly affected by dust concentration. Specific resistance of filter cake increases with velocity, slightly affected by dust concentration, changes inversely with the upper pressure drop limit and decreases over a prolonged use (aging). Specific resistance of filter media is independent of upper pressure drop limit and increases linearly over a prolonged use.

  20. Particle Kalman Filtering: A Nonlinear Framework for Ensemble Kalman Filters

    KAUST Repository

    Hoteit, Ibrahim

    2010-09-19

    Optimal nonlinear filtering consists of sequentially determining the conditional probability distribution functions (pdf) of the system state, given the information of the dynamical and measurement processes and the previous measurements. Once the pdfs are obtained, one can determine different estimates, for instance, the minimum variance estimate, or the maximum a posteriori estimate, of the system state. It can be shown that, many filters, including the Kalman filter (KF) and the particle filter (PF), can be derived based on this sequential Bayesian estimation framework. In this contribution, we present a Gaussian mixture‐based framework, called the particle Kalman filter (PKF), and discuss how the different EnKF methods can be derived as simplified variants of the PKF. We also discuss approaches to reducing the computational burden of the PKF in order to make it suitable for complex geosciences applications. We use the strongly nonlinear Lorenz‐96 model to illustrate the performance of the PKF.

  1. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  2. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  3. Bridging the ensemble Kalman filter and particle filters: the adaptive Gaussian mixture filter

    OpenAIRE

    Stordal, Andreas Størksen; Karlsen, Hans A.; Nævdal, Geir; Hans J. Skaug; Vallès, Brice

    2010-01-01

    The nonlinear filtering problem occurs in many scientific areas. Sequential Monte Carlo solutions with the correct asymptotic behavior such as particle filters exist, but they are computationally too expensive when working with high-dimensional systems. The ensemble Kalman filter (EnKF) is a more robust method that has shown promising results with a small sample size, but the samples are not guaranteed to come from the true posterior distribution. By approximating the model error with a Gauss...

  4. Kalman Filter Tracking on Parallel Architectures

    CERN Document Server

    Cerati, Giuseppe; Lantz, Steven; McDermott, Kevin; Riley, Dan; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2015-01-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors, but the future will be even more exciting. In order to stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Example technologies today include Intel's Xeon Phi and GPGPUs. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High Luminosity LHC, for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques including Cellular Automata or returning to Hough Transform. The most common track finding techniques in use today are however those based on the Kalman Filter. Significant experience has...

  5. Kalman Filter Tracking on Parallel Architectures

    CERN Document Server

    Cerati, Giuseppe; Krutelyov, Slava; Lantz, Steven; Lefebvre, Matthieu; McDermott, Kevin; Riley, Daniel; Tadel, Matevz; Wittich, Peter; Wuerthwein, Frank; Yagil, Avi

    2016-01-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors such as GPGPU, ARM and Intel MIC. To stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High-Luminosity Large Hadron Collider (HL-LHC), for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques such as Cellular Automata or Hough Transforms. The most common track finding techniques in use today, however, are those based on the Kalman Filter. Significant experience has been accumulated with these techniques on real tracking detector sy...

  6. Building Better Bridges: An Evaluation of The Bridge to the Ph.D. Program

    Science.gov (United States)

    Ellyn Sanderson, Robyn; Lobel, Caroline; Agueros, Marcel A.; Anderson, Vanessa; Ash, Summer; Purdie-Vaughns, Valerie; Romero-Canyas, Rainer; Walker, Erica

    2016-01-01

    Columbia University's Bridge to the Ph.D. in the Natural Sciences Program is increasing the number of underrepresented scholars entering graduate programs and equipping them to succeed in these programs. In a given year, three to five Bridge participants are hired as full-time Columbia University research assistants for up to two years. Now in its seventh year, the Program supports seven participants, and its alumni (including five astronomers) have gone on to Ph.D. programs across the country. Although to date fewer than 40 people have participated in the Program, a number too small for an exclusively statistical evaluation of its effectiveness, we are collecting invaluable longitudinal data on the career progressions of underrepresented aspiring scientists across the natural sciences. At least a dozen Bridge alumni will earn their Ph.D. in the next two-three years, and we will then learn much more about the impact that the Bridge Program has had on our participants' trajectories. Among other things, we hope to use these data to determine the Program's effectiveness in developing feelings of self-efficacy and participants' confidence in their ability to succeed in doctoral programs, to measure the rate at which Bridge alumni successfully complete doctoral programs relative to their peers, and to identify the aspects of the Program that participants find most helpful to their progress at different stages of their paths to and through doctoral programs. Here we describe the data we have already obtained as part of our on-going study, and preliminary results from our analysis.

  7. GNSS data filtering optimization for ionospheric observation

    Science.gov (United States)

    D'Angelo, G.; Spogli, L.; Cesaroni, C.; Sgrigna, V.; Alfonsi, L.; Aquino, M. H. O.

    2015-12-01

    In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS data, able to generate and output 50-Hz phase and amplitude samples, are commonly used to study electron density irregularities within the ionosphere. Ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. For scintillation analysis, usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15°, 20° or 30°) are filtered out, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by the environment surrounding the receiver could mimic ionospheric scintillation, because buildings, trees, etc. might create diffusion, diffraction and reflection. Although widely adopted, the elevation angle threshold has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at excluding the multipath sources of non-ionospheric origin to improve the quality of the information obtained by the GNSS signal in a given site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by scintillation receivers. The technique is applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy

  8. An interdepartmental Ph.D. program in computational biology and bioinformatics: the Yale perspective.

    Science.gov (United States)

    Gerstein, Mark; Greenbaum, Dov; Cheung, Kei; Miller, Perry L

    2007-02-01

    Computational biology and bioinformatics (CBB), the terms often used interchangeably, represent a rapidly evolving biological discipline. With the clear potential for discovery and innovation, and the need to deal with the deluge of biological data, many academic institutions are committing significant resources to develop CBB research and training programs. Yale formally established an interdepartmental Ph.D. program in CBB in May 2003. This paper describes Yale's program, discussing the scope of the field, the program's goals and curriculum, as well as a number of issues that arose in implementing the program. (Further updated information is available from the program's website, www.cbb.yale.edu.)

  9. Training of young researchers and PhD supervisors for the future

    DEFF Research Database (Denmark)

    Kolmos, Anette

    2004-01-01

    If Europe is to develop an integrated knowledge society and ERA, the research practice has to be developed. Further development of the research practice can among others take place through training of young researchers, which is not only based on the principles of apprenticeship, but a training...... which contributes to break down the usual ways of thinking and to incorporate both intercultural and interdisciplinary principles, and a valued orientation towards trade and industry. The PhD supervisors should also be trained so that light is thrown on the aims, methods and contents of the supervision...

  10. Synthesis of the PhD thesis "Anti-money laundering and counter terrorism financing management"

    Directory of Open Access Journals (Sweden)

    Camelia Popa

    2013-03-01

    Full Text Available As a whole, this PhD thesis follows three research lines, namely: (1 the conceptual line - concerns the definition of the money laundering and terrorism financing phenomenon, the processes, mechanisms, stages and instruments of the laundering of illegally obtained fund; (2 the estimative line aimed at measuring the size of money laundering phenomenon, the economic, social and security effects and consequences; (3 the line of an awareness of the need to prevent and fight against the effects arising from money laundering processes, the national and international efforts taken until present nation- and worldwide and the future measures required to diminish the consequences of this scourge.

  11. Twenty of China's best physics PhD students visited CERN

    CERN Multimedia

    2006-01-01

    Twenty of the top physics PhD students in China were honoured with the 'E=mc2 to modern science' Einstein Award and received a three week tour of major laboratories in Germany and Switzerland, including CERN, DESY and the Max Planck Institute. The Einstein Award is co-sponsored by the German and Swiss Embassies in celebration of the 'Year of Physics' in 2005. For many years, Germany, Switzerland and China have been involved in numerous areas of scientific research and cooperation.

  12. The first Italian doctorate (PhD Course) in Physics Education Research

    Science.gov (United States)

    Michelini, Marisa; Santi, Lorenzo

    2008-05-01

    The first PhD Italian course in Physics Education Research in Udine aims to qualify young researchers and teachers coming from all the Italian groups of research in the field. It becomes a context for developing research projects carried out following parallel research lines on: Teaching/Learning paths for didactic innovation, cognitive research, ICT for strategies to overcome conceptual knots in physics; E-learning for personalization; d) Computer on-line experiments and modelling; e) Teacher formation and training; f) Informal learning in science.

  13. Graduate and Ph.D. Course on Design and Manufacture of Micro Mechanical Systems

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; De Grave, Arnaud

    2011-01-01

    at the Department of Mechanical Engineering at the Technical University of Denmark. This paper describes the framework of the course that has been applied both at graduate and Ph.D. level. The current structure of the course as well as the pedagogical approach and some examples of final projects will be presented...... it is now well known that micro/nanotechnology is not only a matter of downscaling applications and methods from the macro scale, and therefore an in-depth understanding and knowledge of product and process characteristics at this scale is necessary. Based on this challenge, a new course was developed...

  14. Digital Filters Using Identical Blocks

    Directory of Open Access Journals (Sweden)

    S. C. Dutta

    1985-07-01

    Full Text Available Improved response of non-recursive digital filters is achieved using Amplitude Change Functions (ACFs on a prototype filter. A generalized ACF with interesting properties is suggested. Methods for achieving variable cut-off frequency and frequency transformation are explained. A modular hardware implementation is also presented.

  15. Digital filter synthesis computer program

    Science.gov (United States)

    Moyer, R. A.; Munoz, R. M.

    1968-01-01

    Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list.

  16. Polarizing Filter for Integrated Optics

    Science.gov (United States)

    Ramer, O. G.; Goss, W. C.; Goldstein, R.

    1986-01-01

    Polarizing filter for titanium-doped lithium niobate light waveguide suppresses transverse magnetic (TM) mode of light propagation while allowing transverse electric (TE) mode to continue on its way. Filter - lithium niobate crystal - is expected to find many applications in integrated optical circuits.

  17. Filter-extruded liposomes revisited

    DEFF Research Database (Denmark)

    Hinna, Askell; Steiniger, Frank; Hupfeld, Stefan;

    2016-01-01

    Filter-extrusion is a widely used technique for down-sizing of phospholipid vesicles. In order to gain a detailed insight into size and size distributions of filter-extruded vesicles composed of egg phosphatidyl-choline (with varying fractions of cholesterol) – in relation to extrusionparameters...

  18. Cold Crystal Reflector Filter Concept

    CERN Document Server

    Muhrer, G

    2014-01-01

    In this paper the theoretical concept of a cold crystal reflector filter will be presented. The aim of this concept is to balance the shortcoming of the traditional cold polycrystalline reflector filter, which lies in the significant reduction of the neutron flux right above (in energy space) or right below (wavelength space) the first Bragg edge.

  19. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  20. Kalman Filter Tracking on Parallel Architectures

    Science.gov (United States)

    Cerati, Giuseppe; Elmer, Peter; Lantz, Steven; McDermott, Kevin; Riley, Dan; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2015-12-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors, but the future will be even more exciting. In order to stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Example technologies today include Intel's Xeon Phi and GPGPUs. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High Luminosity LHC, for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques including Cellular Automata or returning to Hough Transform. The most common track finding techniques in use today are however those based on the Kalman Filter [2]. Significant experience has been accumulated with these techniques on real tracking detector systems, both in the trigger and offline. They are known to provide high physics performance, are robust and are exactly those being used today for the design of the tracking system for HL-LHC. Our previous investigations showed that, using optimized data structures, track fitting with Kalman Filter can achieve large speedup both with Intel Xeon and Xeon Phi. We report here our further progress towards an end-to-end track reconstruction algorithm fully exploiting vectorization and parallelization techniques in a realistic simulation setup.

  1. Identification Filtering with fuzzy estimations

    Directory of Open Access Journals (Sweden)

    J.J Medel J

    2012-10-01

    Full Text Available A digital identification filter interacts with an output reference model signal known as a black-box output system. The identification technique commonly needs the transition and gain matrixes. Both estimation cases are based on mean square criterion obtaining of the minimum output error as the best estimation filtering. The evolution system represents adaptive properties that the identification mechanism includes considering the fuzzy logic strategies affecting in probability sense the evolution identification filter. The fuzzy estimation filter allows in two forms describing the transition and the gain matrixes applying actions that affect the identification structure. Basically, the adaptive criterion conforming the inference mechanisms set, the Knowledge and Rule bases, selecting the optimal coefficients in distribution form. This paper describes the fuzzy strategies applied to the Kalman filter transition function, and gain matrixes. The simulation results were developed using Matlab©.

  2. DSP Control of Line Hybrid Active Filter

    DEFF Research Database (Denmark)

    Dan, Stan George; Benjamin, Doniga Daniel; Magureanu, R.;

    2005-01-01

    Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter ...

  3. Inhibition of PHD3 by salidroside promotes neovascularization through cell–cell communications mediated by muscle-secreted angiogenic factors

    Science.gov (United States)

    Zhang, Jing; Kasim, Vivi; Xie, Yu-Dan; Huang, Can; Sisjayawan, Julita; Dwi Ariyanti, Agnes; Yan, Xue-Song; Wu, Xiao-Yan; Liu, Cai-Ping; Yang, Li; Miyagishi, Makoto; Wu, Shou-Rong

    2017-01-01

    Therapeutic angiogenesis has been considered as a potential strategy for treating peripheral artery diseases including hind-limb ischemia (HLI); however, no effective drug-based treatment is currently available. Here we showed that intramuscular administration of salidroside, an active compound of Chinese herb Rhodiola, could robustly enhance blood perfusion recovery by promoting neovascularization in HLI mice. We revealed that salidroside promoted skeletal muscle cell migration and paracrine function through inhibiting the transcriptional level of prolyl-hydroxylase domain 3 (PHD3) without affecting PHD1 and PHD2. Paracrine signals from salidroside-treated skeletal muscle cells enhanced endothelial and smooth muscle cells migration, while inhibition of FGF2/FGF2R and PDGF-BB/PDGFR-β pathways abolished this effect, as well as neovascularization in HLI mice. Furthermore, we elucidated that salidroside inhibition on PHD3 might occur through estrogen receptor alpha (ERα). Together, our findings highlights the potential application of salidroside as a novel pharmalogical inhibitor of ERα/PHD3 axis for therapeutic angiogenesis in HLI diseases. PMID:28266625

  4. PERFORMANCE ANALYSIS OF A MODIFIED DECOMPOSITION FILTER FOR NON IDENTICAL NOISES

    Directory of Open Access Journals (Sweden)

    K. Vasanth

    2010-11-01

    Full Text Available The proposed work aims in the restoration of images corrupted by Gaussian noise, impulse noise. The new algorithm significantly removes different noises and produce better image quality than standard median filter (SMF, Centre weighted median filter (CWF and threshold decomposition filter (TDF.The proposed algorithm (PA is tested on different images corrupted by all two noises and is found to produce better results in terms of the qualitative and quantitative measures of the image for noise densities up to 30% noise level for impulse noise, mean zero and 0.9% variance of Gaussian noise. The filter works well for speckle noise up to 0.8% variance.

  5. Sensory Pollution from Bag Filters, Carbon Filters and Combinations

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

    2008-01-01

    Used ventilation filters are a major source of sensory pollutants in air handling systems. The objective of the present study was to evaluate the net effect that different combinations of filters had on perceived air quality after 5 months of continuous filtration of outdoor suburban air. A panel....... Furthermore, its pressure drop changed very little during the 5 months of service, and it had the added benefit of removing a large fraction of ozone from the airstream. If similar results are obtained over a wider variety of soiling conditions, such filters may be a viable solution to a long recognized...

  6. Next gen PhD a guide to career paths in science

    CERN Document Server

    Sinche, Melanie V

    2016-01-01

    For decades, top scientists in colleges and universities pursued a clear path to success: enroll in a prestigious graduate program, conduct research, publish papers, complete the PhD, pursue postdoctoral work. With perseverance and a bit of luck, a tenure-track professorship awaited at the end. In today s academic job market, this scenario represents the exception. As the number of newly conferred science PhDs keeps rising, the number of tenured professorships remains stubbornly stagnant. Only 14 percent of those with PhDs in science occupy tenure-track positions five years after completing their degree. Next Gen PhD provides a frank and up-to-date assessment of the current career landscape facing science PhDs. Nonfaculty careers once considered Plan B are now preferred by the majority of degree holders, says Melanie Sinche. An upper-level science degree is a prized asset in the eyes of many employers, and a majority of science PhDs build rewarding careers both inside and outside the university. A certified ...

  7. Home healthcare settop-box for senior chronic care using ISO/IEEE 11073 PHD standard.

    Science.gov (United States)

    Lim, Joon-Ho; Park, Chanyong; Park, Soo-Jun

    2010-01-01

    As the number of seniors with chronic disease increases, the need of home healthcare settop-box is increased to manage their chronic disease in their home environment. Using the home healthcare settop-box, the patients can regularly check their health data, and finally, it can lead the decrease of medical expenses. For the home healthcare settop-box, the most important factor is the standard compatibility, which can interoperate with standard devices of any other companies. In this paper, we propose a home healthcare settop-box using ISO/IEEE 11073 PHD standard. It collects health data according to the PHD standard, and provides a chronic-care service based on the collected data. The proposed settop-box is connected with 3 devices of weigh scale, blood pressure monitor, and glucose meter, and tested at 10 homes for a month. Lastly, the proposed settop-box can be used for various healthcare services such as Google Health and Telemedicine Services using a healthcare platform server.

  8. First ‘Gentner Doktor’ finishes PhD at CERN

    CERN Multimedia

    Jordan Juras

    2011-01-01

    In 2007, the CERN Doctoral Student Programme saw the addition of the Gentner Doctoral Student Programme, named in honour of the celebrated nuclear physicist, Wolfgang Gentner. Four years later, on 22 June 2011, Marcel Schuh finished his PhD with a thesis in the field of accelerator technology and became the very first ‘Gentner Doktor’.   Marcel Schuh, first 'Gentner Doktor', celebrates completing his PhD. (Photo by Carsten P. Welsch) Marcel Schuh became a Gentner student in April 2008, after completing a physics degree in 2007 at the University of Heidelberg. His thesis allowed him to gain exposure to CERN and the LHC, as he worked on monitoring and control systems for trigger and readout electronics on the ALICE detector at the LHC. With the support of university supervisor, Carsten P. Welsch, Schuh applied for a Gentner Doctoral Studentship on the Superconducting Proton Linac (SPL) project. “My task was to evaluate whether dedicated higher order mode (HOM) coupler...

  9. A simplified transfer function for estimating saturated hydraulic conductivity of porous drainage filters

    DEFF Research Database (Denmark)

    Canga, Eriona; Iversen, Bo Vangsø; Kjærgaard, Charlotte

    2013-01-01

    Knowledge of the saturated hydraulic conductivity (Ksat) of porous filters used in water treatment technologies is important for optimizing the retention of nutrients and pollutants. This parameter determines the hydraulic capacity, which together with the Chemical properties of the filter media......, bulk density, uniformity coefficient, particle density, and porosity of 46 porous media fractions. The fractions ranged in grain size from 0.5 to 20 mm and were obtained from seven commercial available coarse filter materials. A backward stepwise regression analysis was performed between Ksat and 10...

  10. Design of the annular binary filters with super-resolution based on the genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    YU Qi-lei; LE Zi-chun; ZHU Hong-ying

    2006-01-01

    To improve the density of information storage,this paper introduces a kind of annular binary filters with super-resolution,Several of these filters have been designed based on the genetic algorithm,the simulations demonstrate that the transverse gain of the filters can reach the value of 1.37.Thus they can remarkably decrease the recording spot size,which is helpful to improve the density of information storage and to make the depth of focus longer,and therefore they can avoid the mistake caused by the small undulation of the optical disk in the process of recording/reading the information.

  11. Advanced Filtering Techniques Applied to Spaceflight Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IST-Rolla developed two nonlinear filters for spacecraft orbit determination during the Phase I contract. The theta-D filter and the cost based filter, CBF, were...

  12. Shunt Active Filter in Damping Harmonics Propagation

    Directory of Open Access Journals (Sweden)

    BERBAOUI, B.

    2010-08-01

    Full Text Available This paper deals with a hybrid shunt active power filter applied on 500 kV HVDC, after a description of the causes and effects harmonic pollution which may damage equipments and interrupt electric power customers service; in this paper we present the deferent solutions of this problem among one has to study the two most recent types of filtering: passive and hybrid filter. The hybrid filter consists of active filter connected in shunt with passive filter. The hybrid shunt active filter proposed is based on three levels PWM inverter and characterized by detecting the harmonic current flowing into the passive filter and controlled by notch algorithm. This structure has been applied on a test HVDC power system, is presented as a technical solution makes it possible to eliminate the disadvantages from passive filtering, and also economic price of active filtering part. The simulation results justified the effectiveness of this type of filter face of the classic passive filter.

  13. Nanophotonic filters for digital imaging

    Science.gov (United States)

    Walls, Kirsty

    There has been an increasing demand for low cost, portable CMOS image sensors because of increased integration, and new applications in the automotive, mobile communication and medical industries, amongst others. Colour reproduction remains imperfect in conventional digital image sensors, due to the limitations of the dye-based filters. Further improvement is required if the full potential of digital imaging is to be realised. In alternative systems, where accurate colour reproduction is a priority, existing equipment is too bulky for anything but specialist use. In this work both these issues are addressed by exploiting nanophotonic techniques to create enhanced trichromatic filters, and multispectral filters, all of which can be fabricated on-chip, i.e. integrated into a conventional digital image sensor, to create compact, low cost, mass produceable imaging systems with accurate colour reproduction. The trichromatic filters are based on plasmonic structures. They exploit the excitation of surface plasmon resonances in arrays of subwavelength holes in metal films to filter light. The currently-known analytical expressions are inadequate for optimising all relevant parameters of a plasmonic structure. In order to obtain arbitrary filter characteristics, an automated design procedure was developed that integrated a genetic algorithm and 3D finite-difference time-domain tool. The optimisation procedure's efficacy is demonstrated by designing a set of plasmonic filters that replicate the CIE (1931) colour matching functions, which themselves mimic the human eye's daytime colour response.

  14. Columbia's Bridge to the Ph.D. Program: A research-focused initiative facilitating the transition to graduate school

    Science.gov (United States)

    Agüeros, Marcel A.

    2015-01-01

    Columbia University's Bridge to the Ph.D. in the Natural Sciences Program aims to enhance the participation of students from underrepresented groups in Ph.D. programs. To achieve this, the Bridge Program provides an intensive research, coursework, and mentoring experience to post-baccalaureates seeking to strengthen their graduate school applications and to prepare for the transition into graduate school. To date, 20 Bridge Program alumni --- including four in astronomy --- have gone on to Ph.D. programs at Columbia, the University of Michigan, Johns Hopkins, the University of Washington, Albert Einstein, Yale, and SUNY-Albany, among others. In this talk, I will touch on some of the connections between Pre-MAP and the Bridge Program, and particularly how my involvement in the former prepared me to lead the latter.

  15. Ensemble Kalman filtering in presence of inequality constraints

    Science.gov (United States)

    van Leeuwen, P. J.

    2009-04-01

    Kalman filtering is presence of constraints is an active area of research. Based on the Gaussian assumption for the probability-density functions, it looks hard to bring in extra constraints in the formalism. On the other hand, in geophysical systems we often encounter constraints related to e.g. the underlying physics or chemistry, which are violated by the Gaussian assumption. For instance, concentrations are always non-negative, model layers have non-negative thickness, and sea-ice concentration is between 0 and 1. Several methods to bring inequality constraints into the Kalman-filter formalism have been proposed. One of them is probability density function (pdf) truncation, in which the Gaussian mass from the non-allowed part of the variables is just equally distributed over the pdf where the variables are alolwed, as proposed by Shimada et al. 1998. However, a problem with this method is that the probability that e.g. the sea-ice concentration is zero, is zero! The new method proposed here does not have this drawback. It assumes that the probability-density function is a truncated Gaussian, but the truncated mass is not distributed equally over all allowed values of the variables, but put into a delta distribution at the truncation point. This delta distribution can easily be handled with in Bayes theorem, leading to posterior probability density functions that are also truncated Gaussians with delta distributions at the truncation location. In this way a much better representation of the system is obtained, while still keeping most of the benefits of the Kalman-filter formalism. In the full Kalman filter the formalism is prohibitively expensive in large-scale systems, but efficient implementation is possible in ensemble variants of the kalman filter. Applications to low-dimensional systems and large-scale systems will be discussed.

  16. Simulasi Perancangan Filter Analog dengan Respon Chebyshev

    Directory of Open Access Journals (Sweden)

    RUSTAMAJI RUSTAMAJI

    2016-02-01

    Full Text Available Abstrak Dalam suatu sistem komunikasi penggunaan rangkaian filter sangat penting. Salah satu cara untuk memudahkan dalam perancangan sebuah filter dilakukanlah teknik simulasi. Penelitian ini bertujuan untuk merancang simulasi yang menghasilkan respon filter jenis chebyshev serta menghasilkan nilai komponen induktor (L dan kapasitor (C yang dibutuhkan untuk merangkai filter. Simulasi yang dirancang pada penelitian ini menggunakan Graphical User Interface (GUI. Dari simulasi yang dilakukan, didapatkan respon Chebyshev pada low pass filter, high pass filter, band pass filter, dan band stop filter sudah sesuai dengan input yang dimasukkan ke dalam parameter program dan sesuai dengan teori respon filter Chebyshev. Hasil Simulasi dari rangkaian band pass filter dan band stop filter dengan menggunakan Electronic Workbench (EWB, menunjukkan respon dengan pergeseran frekuensi sebesar 0,1 kHz lebih tinggi dari frekuensi yang diharapkan. Kata Kunci :filter, Chebyshev, band, respon frekuensi.   Abstract On communication system using filter is very important. One way to simplify the design of filter undertaken a simulation technique. This research aims to design a simulation that generates the filter response of chebyshev and generate the value component of the inductor (L and capacitor (C that needed for constructing the filter. This Simulation using Graphical User Interface (GUI. From result simulation, response in low pass filter, high pass filter, band pass filter, band stop filter and is in compliance with the input entered into the program and in accordance with the theory of Chebyshev filter response. The simulation of the band pass filter and bands stop filter by using electronic workbench ( EWB , show a response with shifts frequency of 0.1 khz higher than frequency expected.   Keywords: filter, Chebyshev, band, frequency respons

  17. Pragmatic circuits signals and filters

    CERN Document Server

    Eccles, William

    2006-01-01

    Pragmatic Circuits: Signals and Filters is built around the processing of signals. Topics include spectra, a short introduction to the Fourier series, design of filters, and the properties of the Fourier transform. The focus is on signals rather than power. But the treatment is still pragmatic. For example, the author accepts the work of Butterworth and uses his results to design filters in a fairly methodical fashion. This third of three volumes finishes with a look at spectra by showing how to get a spectrum even if a signal is not periodic. The Fourier transform provides a way of dealing wi

  18. Tunable Imaging Filters in Astronomy

    CERN Document Server

    Bland-Hawthorn, J

    2000-01-01

    While tunable filters are a recent development in night time astronomy, they have long been used in other physical sciences, e.g. solar physics, remote sensing and underwater communications. With their ability to tune precisely to a given wavelength using a bandpass optimized for the experiment, tunable filters are already producing some of the deepest narrowband images to date of astrophysical sources. Furthermore, some classes of tunable filters can be used in fast telescope beams and therefore allow for narrowband imaging over angular fields of more than a degree over the sky.

  19. Simplified design of filter circuits

    CERN Document Server

    Lenk, John

    1999-01-01

    Simplified Design of Filter Circuits, the eighth book in this popular series, is a step-by-step guide to designing filters using off-the-shelf ICs. The book starts with the basic operating principles of filters and common applications, then moves on to describe how to design circuits by using and modifying chips available on the market today. Lenk's emphasis is on practical, simplified approaches to solving design problems.Contains practical designs using off-the-shelf ICsStraightforward, no-nonsense approachHighly illustrated with manufacturer's data sheets

  20. Properties of ceramic candle filters

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1995-06-01

    The mechanical integrity of ceramic filter elements is a key issue for hot gas cleanup systems. To meet the demands of the advanced power systems, the filter components must sustain the thermal stresses of normal operations (pulse cleaning), of start-up and shut-down conditions, and of unanticipated process upsets such as excessive ash accumulation without catastrophic failure. They must also survive the various mechanical loads associated with handling and assembly, normal operation, and process upsets. For near-term filter systems, these elements must survive at operating temperatures of 1650{degrees}F for three years.