A Fast, Robust, Automatic Blink Detector
Directory of Open Access Journals (Sweden)
Javad Sayahzadeh
2014-11-01
Full Text Available Introduction “Blink” is defined as closing and opening of the eyes in a small duration of time. In this study, we aimed to introduce a fast, robust, vision-based approach for blink detection. Materials and Methods This approach consists of two steps. In the first step, the subject’s face is localized every second and with the first blink, the system detects the eye’s location and creates an open-eye template image. In the second step, the eye is tracked, using sum of squared differences (SSD. This system can classify the state of the eyes as open, closed, or lost, using the SSD-based classifier. If the eyes are closed as in usual blinking, the blink will be detected. To classify eyes as closed or open, two adaptive thresholds were proposed; therefore, factors such as the subject’s distance from the camera or environment illumination did not affect the system performance. In addition, in order to improve system performance, a new feature, called "peak-to-neighbors ratio", was proposed. Results The accuracy of this system was 96.03%, based on the evaluation on Zhejiang University (ZJU dataset, and 98.59% in our own dataset. Conclusion The present system was faster than other systems, which use normalized correlation coefficient (NCC for eye tracking, since time complexity of SSD is lower than that of NCC. The achieved processing rate for ZJU dataset was 35 fps.
Realisation of a novel crystal bender for a fast double crystal monochromator
Energy Technology Data Exchange (ETDEWEB)
Zaeper, R.; Richwin, M. E-mail: richwin@uni-wuppertal.de; Wollmann, R.; Luetzenkirchen-Hecht, D.; Frahm, R
2001-07-21
A novel crystal bender for an X-ray undulator beamline as part of a fast double crystal monochromator development for full EXAFS energy range was characterized. Rocking curves of the monochromator crystal system were recorded under different heat loads and bending forces of the indirectly cooled first Si(1 1 1) crystal. The monochromator development implements new piezo-driven tilt tables with wide angular range to adjust the crystals' Bragg angles and a high pressure actuated bender mechanism for the first crystal.
Realisation of a novel crystal bender for a fast double crystal monochromator
Zaeper, R; Wollmann, R; Luetzenkirchen-Hecht, D; Frahm, R
2001-01-01
A novel crystal bender for an X-ray undulator beamline as part of a fast double crystal monochromator development for full EXAFS energy range was characterized. Rocking curves of the monochromator crystal system were recorded under different heat loads and bending forces of the indirectly cooled first Si(1 1 1) crystal. The monochromator development implements new piezo-driven tilt tables with wide angular range to adjust the crystals' Bragg angles and a high pressure actuated bender mechanism for the first crystal.
A Fast and Robust Method for Measuring Optical Channel Gain
DEFF Research Database (Denmark)
Harbo, Anders La-Cour; Stoustrup, Jakob; Villemoes, L.F.
2000-01-01
We present a numerically stable and computational simple method for fast and robust measurement of optical channel gain. By transmitting adaptively designed signals through the channel, good accuracy is possible even in severe noise conditions......We present a numerically stable and computational simple method for fast and robust measurement of optical channel gain. By transmitting adaptively designed signals through the channel, good accuracy is possible even in severe noise conditions...
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Hansen, Peter Reinhard; Lunde, Asger
2011-01-01
We propose a multivariate realised kernel to estimate the ex-post covariation of log-prices. We show this new consistent estimator is guaranteed to be positive semi-definite and is robust to measurement error of certain types and can also handle non-synchronous trading. It is the first estimator...
Directory of Open Access Journals (Sweden)
Kosiorowska Ewa
2015-06-01
Full Text Available We briefly communicate the results of nonparametric and robust evaluation of the effects of the Fourth Millennium Development Goal of the United Nations. The main aim of the goal was reducing by two thirds, from 1990-2015, under five month’s child mortality. Our novel analysis was conducted by means of very powerful and user friendly tools offered by the Data Depth Concept being a collection of multivariate techniques basing on multivariate generalizations of quintiles, ranges and order statistics. The results of our analysis are more convincing than the results obtained using classical statistical tools.
Fast and Robust Stereo Vision Algorithm for Obstacle Detection
Institute of Scientific and Technical Information of China (English)
Yi-peng Zhou
2008-01-01
Binocular computer vision is based on bionics, after the calibration through the camera head by double-exposure image synchronization, access to the calculation of two-dimensional image pixels of the three-dimensional depth information. In this paper, a fast and robust stereo vision algorithm is described to perform in-vehicle obstacles detection and characterization. The stereo algorithm which provides a suitable representation of the geometric content of the road scene is described, and an in-vehicle embedded system is presented. We present the way in which the algorithm is used, and then report experiments on real situations which show that our solution is accurate, reliable and efficient. In particular, both processes are fast, generic,robust to noise and bad conditions, and work even with partial occlusion.
A robust and fast generic voltage sag detection technique
DEFF Research Database (Denmark)
L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.;
2015-01-01
In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference frame......, the algorithm can rapidly identify the starting and the ending of symmetric and asymmetric voltage sags, even if there are harmonics on the grid. Simulation and experimental results are given to validate the proposed algorithm....
Energy Technology Data Exchange (ETDEWEB)
Zenatti, D. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires
1969-07-01
Development of a device for the enlargement of the domain of application of classical oscilloscopes to the observation of fast single pulses by application of the sampling principle. Its principal characteristics are: Bandwidth of 700 MHz; Maximum sensibility of 50 mV; Maximum amplitude of input signal of {+-} 1 V; Number of samples of 16; Samples separation of 0,2 ns. (author) [French] Realisation d'un dispositif permettant d'elargir le domaine d'utilisation des oscilloscopes classiques en appliquant le principe de l'echantillonnage a l'observation d'un signal bref unique. Les principales caracteristiques sont les suivantes: Bande passante de 700 MHz; Sensibilite maximale de 50 mV; Amplitude maximale du signal a echantillonner de {+-} 1 V; Nombre de points d'echantillonnage de 16; Pas d'echantillonnage de 0,2 ns. (auteur)
Fast and robust recognition and localization of 2D objects
Otterbach, Rainer; Gerdes, Rolf; Kammueller, R.
1994-11-01
The paper presents a vision system which provides a robust model-based identification and localization of 2-D objects in industrial scenes. A symbolic image description based on the polygonal approximation of the object silhouettes is extracted in video real time by the use of dedicated hardware. Candidate objects are selected from the model database using a time and memory efficient hashing algorithm. Any candidate object is submitted to the next computation stage which generates pose hypotheses by assigning model to image contours. Corresponding continuous measures of similarity are derived from the turning functions of the curves. Finally, the previous generated hypotheses are verified using a voting scheme in transformation space. Experimental results reveal the fault tolerance of the vision system with regard to noisy and split image contours as well as partial occlusion of objects. THe short cycle time and the easy adaptability of the vision system make it well suited for a wide variety of applications in industrial automation.
Improvement in fast particle track reconstruction with robust statistics
Energy Technology Data Exchange (ETDEWEB)
Aartsen, M.G. [School of Chemistry and Physics, University of Adelaide, Adelaide 5005, SA (Australia); Abbasi, R. [Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Abdou, Y. [Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium); Ackermann, M. [DESY, D-15735 Zeuthen (Germany); Adams, J. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A. [Département de physique nucléaire et corpusculaire, Université de Genève, CH-1211Genève (Switzerland); Ahlers, M. [Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Altmann, D. [Institut für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin (Germany); Auffenberg, J. [Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Bai, X. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Baker, M. [Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Barwick, S.W. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Baum, V. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Bay, R. [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others
2014-02-01
The IceCube project has transformed 1 km{sup 3} of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction is inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This paper describes work on two problems: (1) the track reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detector's early reconstruction with data filters and robust statistical techniques. These can be implemented at the level of on-line reconstruction and, therefore, improve all subsequent reconstructions. Using the metric of median angular resolution, a standard metric for track reconstruction, we improve the accuracy in the initial reconstruction direction by 13%. We also present improvements in measuring the number of muons in coincident events: we can accurately determine the number of muons 98% of the time.
Fast, accurate, robust and Open Source Brain Extraction Tool (OSBET)
Namias, R.; Donnelly Kehoe, P.; D'Amato, J. P.; Nagel, J.
2015-12-01
The removal of non-brain regions in neuroimaging is a critical task to perform a favorable preprocessing. The skull-stripping depends on different factors including the noise level in the image, the anatomy of the subject being scanned and the acquisition sequence. For these and other reasons, an ideal brain extraction method should be fast, accurate, user friendly, open-source and knowledge based (to allow for the interaction with the algorithm in case the expected outcome is not being obtained), producing stable results and making it possible to automate the process for large datasets. There are already a large number of validated tools to perform this task but none of them meets the desired characteristics. In this paper we introduced an open source brain extraction tool (OSBET), composed of four steps using simple well-known operations such as: optimal thresholding, binary morphology, labeling and geometrical analysis that aims to assemble all the desired features. We present an experiment comparing OSBET with other six state-of-the-art techniques against a publicly available dataset consisting of 40 T1-weighted 3D scans and their corresponding manually segmented images. OSBET gave both: a short duration with an excellent accuracy, getting the best Dice Coefficient metric. Further validation should be performed, for instance, in unhealthy population, to generalize its usage for clinical purposes.
Robust, accurate and fast automatic segmentation of the spinal cord.
De Leener, Benjamin; Kadoury, Samuel; Cohen-Adad, Julien
2014-09-01
Spinal cord segmentation provides measures of atrophy and facilitates group analysis via inter-subject correspondence. Automatizing this procedure enables studies with large throughput and minimizes user bias. Although several automatic segmentation methods exist, they are often restricted in terms of image contrast and field-of-view. This paper presents a new automatic segmentation method (PropSeg) optimized for robustness, accuracy and speed. The algorithm is based on the propagation of a deformable model and is divided into three parts: firstly, an initialization step detects the spinal cord position and orientation using a circular Hough transform on multiple axial slices rostral and caudal to the starting plane and builds an initial elliptical tubular mesh. Secondly, a low-resolution deformable model is propagated along the spinal cord. To deal with highly variable contrast levels between the spinal cord and the cerebrospinal fluid, the deformation is coupled with a local contrast-to-noise adaptation at each iteration. Thirdly, a refinement process and a global deformation are applied on the propagated mesh to provide an accurate segmentation of the spinal cord. Validation was performed in 15 healthy subjects and two patients with spinal cord injury, using T1- and T2-weighted images of the entire spinal cord and on multiecho T2*-weighted images. Our method was compared against manual segmentation and against an active surface method. Results show high precision for all the MR sequences. Dice coefficients were 0.9 for the T1- and T2-weighted cohorts and 0.86 for the T2*-weighted images. The proposed method runs in less than 1min on a normal computer and can be used to quantify morphological features such as cross-sectional area along the whole spinal cord.
Fast and robust segmentation in the SDO-AIA era
Verbeeck, Cis; Delouille, Véronique; Mampaey, Benjamin; Hochedez, Jean-François; Boyes, David; Barra, Vincent
Solar images from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Ob-servatory (SDO) will flood the solar physics community with a wealth of information on solar variability, of great importance both in solar physics and in view of Space Weather applica-tions. Obtaining this information, however, requires the ability to automatically process large amounts of data in an objective fashion. In previous work, we have proposed a multi-channel unsupervised spatially-constrained multi-channel fuzzy clustering algorithm (SPoCA) that automatically segments EUV solar images into Active Regions (AR), Coronal Holes (CH), and Quiet Sun (QS). This algorithm will run in near real time on AIA data as part of the SDO Feature Finding Project, a suite of software pipeline modules for automated feature recognition and analysis for the imagery from SDO. After having corrected for the limb brightening effect, SPoCA computes an optimal clustering with respect to the regions of interest using fuzzy logic on a quality criterion to manage the various noises present in the images and the imprecision in the definition of the above regions. Next, the algorithm applies a morphological opening operation, smoothing the cluster edges while preserving their general shape. The process is fast and automatic. A lower size limit is used to distinguish AR from Bright Points. As the algorithm segments the coronal images according to their brightness, it might happen that an AR is detected as several disjoint pieces, if the brightness in between is somewhat lower. Morphological dilation is employed to reconstruct the AR themselves from their constituent pieces. Combining SPoCA's detection of AR, CH, and QS on subsequent images allows automatic tracking and naming of any region of interest. In the SDO software pipeline, SPoCA will auto-matically populate the Heliophysics Events Knowledgebase(HEK) with Active Region events. Further, the algorithm has a huge potential for correct and
What happens after realisation?
DEFF Research Database (Denmark)
Sobisch, Jan-Ulrich
2015-01-01
In this article the questions is raised whether spiritual accomplishment has consequences for ethicals. In particular it is investigated whether the realisation of the illusionary nature of all phenomena may lead in certain forms of Tibetan Buddhism to a neglect of ethical conduct....
Realisation, experience, and purification
DEFF Research Database (Denmark)
Sobisch, Jan-Ulrich
2013-01-01
Often Buddhist mantra practises are portrayed as making and maintaining meditation experiences. Jigten Sumgön explains in his dGongs gcig (5.19) that such a 'making and maintaining' is only a mental fabrication and needs to be purified. Realisation does not arise from experience, but from...
DREAM - A Novel Approach for Robust, Ultra-Fast, Multi-Slice B1 Mapping
Nehrke, K.; Boernert, P.
2012-01-01
Fast and robust in vivo B1 mapping is an essential prerequisite forquantitative MRI or multi-element transmit applications like RF-shimming or accelerated multi-dimensional RF pulses. However, especially at higher field strength, the acquisition speed of current B1-mapping approaches is typicall
Fast and Robust CD and DGD Estimation Based on Data-Aided Channel Estimation
DEFF Research Database (Denmark)
Pittalà, Fabio; Hauske, Fabian N.; Ye, Yabin;
2011-01-01
In this paper data-aided (DA) frequency domain (FD) channel estimation in a 2×2 multi-input-multi-output (MIMO) system is investigated. Using orthogonal training sequences, fast and robust CD and DGD estimation is demonstrated for a 112 Gbit/s PDM-QPSK system over a wide range of combined linear...
Robust and fast schemes in broadband active noise and vibration control
Fraanje, Petrus Rufus
2004-01-01
This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods.
Robust and fast schemes in broadband active noise and vibration control
Fraanje, P.R.
2004-01-01
This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods.
Fast and Robust Segmentation and Classification for Change Detection in Urban Point Clouds
Roynard, X.; Deschaud, J.-E.; Goulette, F.
2016-06-01
Change detection is an important issue in city monitoring to analyse street furniture, road works, car parking, etc. For example, parking surveys are needed but are currently a laborious task involving sending operators in the streets to identify the changes in car locations. In this paper, we propose a method that performs a fast and robust segmentation and classification of urban point clouds, that can be used for change detection. We apply this method to detect the cars, as a particular object class, in order to perform parking surveys automatically. A recently proposed method already addresses the need for fast segmentation and classification of urban point clouds, using elevation images. The interest to work on images is that processing is much faster, proven and robust. However there may be a loss of information in complex 3D cases: for example when objects are one above the other, typically a car under a tree or a pedestrian under a balcony. In this paper we propose a method that retain the three-dimensional information while preserving fast computation times and improving segmentation and classification accuracy. It is based on fast region-growing using an octree, for the segmentation, and specific descriptors with Random-Forest for the classification. Experiments have been performed on large urban point clouds acquired by Mobile Laser Scanning. They show that the method is as fast as the state of the art, and that it gives more robust results in the complex 3D cases.
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Hansen, Peter Reinhard; Lunde, Asger
2011-01-01
In a recent paper we have introduced the class of realised kernel estimators of the increments of quadratic variation in the presence of noise. We showed that this estimator is consistent and derived its limit distribution under various assumptions on the kernel weights. In this paper we extend our...... analysis, looking at the class of subsampled realised kernels and we derive the limit theory for this class of estimators. We find that subsampling is highly advantageous for estimators based on discontinuous kernels, such as the truncated kernel. For kinked kernels, such as the Bartlett kernel, we show...... that subsampling is impotent, in the sense that subsampling has no effect on the asymptotic distribution. Perhaps surprisingly, for the efficient smooth kernels, such as the Parzen kernel, we show that subsampling is harmful as it increases the asymptotic variance. We also study the performance of subsampled...
Reinforced Extreme Learning Machines for Fast Robust Regression in the Presence of Outliers.
Frenay, Benoit; Verleysen, Michel
2016-12-01
Extreme learning machines (ELMs) are fast methods that obtain state-of-the-art results in regression. However, they are not robust to outliers and their meta-parameter (i.e., the number of neurons for standard ELMs and the regularization constant of output weights for L2 -regularized ELMs) selection is biased by such instances. This paper proposes a new robust inference algorithm for ELMs which is based on the pointwise probability reinforcement methodology. Experiments show that the proposed approach produces results which are comparable to the state of the art, while being often faster.
Swarm: robust and fast clustering method for amplicon-based studies
Directory of Open Access Journals (Sweden)
Frédéric Mahé
2014-09-01
Full Text Available Popular de novo amplicon clustering methods suffer from two fundamental flaws: arbitrary global clustering thresholds, and input-order dependency induced by centroid selection. Swarm was developed to address these issues by first clustering nearly identical amplicons iteratively using a local threshold, and then by using clusters’ internal structure and amplicon abundances to refine its results. This fast, scalable, and input-order independent approach reduces the influence of clustering parameters and produces robust operational taxonomic units.
Tilly, David; Ahnesjö, Anders
2015-07-01
A fast algorithm is constructed to facilitate dose calculation for a large number of randomly sampled treatment scenarios, each representing a possible realisation of a full treatment with geometric, fraction specific displacements for an arbitrary number of fractions. The algorithm is applied to construct a dose volume coverage probability map (DVCM) based on dose calculated for several hundred treatment scenarios to enable the probabilistic evaluation of a treatment plan. For each treatment scenario, the algorithm calculates the total dose by perturbing a pre-calculated dose, separately for the primary and scatter dose components, for the nominal conditions. The ratio of the scenario specific accumulated fluence, and the average fluence for an infinite number of fractions is used to perturb the pre-calculated dose. Irregularities in the accumulated fluence may cause numerical instabilities in the ratio, which is mitigated by regularisation through convolution with a dose pencil kernel. Compared to full dose calculations the algorithm demonstrates a speedup factor of ~1000. The comparisons to full calculations show a 99% gamma index (2%/2 mm) pass rate for a single highly modulated beam in a virtual water phantom subject to setup errors during five fractions. The gamma comparison shows a 100% pass rate in a moving tumour irradiated by a single beam in a lung-like virtual phantom. DVCM iso-probability lines computed with the fast algorithm, and with full dose calculation for each of the fractions, for a hypo-fractionated prostate case treated with rotational arc therapy treatment were almost indistinguishable.
DEFF Research Database (Denmark)
Bertelsen, Niels Haldor; Hansen, Ernst Jan de Place
Repræsentanter for byggesektoren har på 11 dialogmøder drøftet Erhvervs- og Byggestyrelsens "Vision 2020 - Byggeri med mening". Drøftelserne førte til formulering af en lang række initiativforslag til realisering af visionen. Den mest centrale udfordring bliver at reducere fejl og mangler i...... byggeriet. Branchen lægger også vægt på, at styringen af Vision 2020s reaisering sker i byggesektoren. Initiativforslagene er i rapporten samlet under 3 hovedområder. Det første hovedområde lægger vægt på bygningerne, brugerbehov og det globale samfund. Det andet omhandler processen og leverancesystemet...
Robust and Fast Initialization for Intensity-Based 2D/3D Registration
Directory of Open Access Journals (Sweden)
Zhenzhou Shao
2014-06-01
Full Text Available Intensity-based 2D/3D registration is a key technique using digitally reconstructed radiographs (DRRs to register the preoperative volume to the patient setup during the operation. Although DRR-based method provides a high accuracy, the small capture range hinders its clinical use. In this paper, such problem was addressed by a robust and fast initialization method using a two-level scheme including automatic tracking-based initialization (Level I and multiresolution estimation based on central-slice theorem and phase correlation (Level II. It provided almost optimal transformation parameters for intensity-based registration. Experiments using a public gold standard data set and a spinal phantom have been conducted. The mean target registration error (mTRE was limited in the range from 2.12 mm to 22.57 mm after tracking-based initialization. The capture range based on level II only was 20.1 mm and the mTRE in this capture range was 2.92 ± 2.21 mm. The intensity-based 2D/3D registration using proposed two-level initialization achieved the successful rate of 84.8% with the average error of 2.36 mm. The experimental results showed that the proposed method yielded the robust and fast initialization for intensity-based registration methods. In a similar way, it can be applied to other registration methods to enable a larger capture range and robust implementation.
A FAST AND ROBUST ALGORITHM FOR ROAD EDGES EXTRACTION FROM LIDAR DATA
Directory of Open Access Journals (Sweden)
K. Qiu
2016-06-01
Full Text Available Fast mapping of roads plays an important role in many geospatial applications, such as infrastructure planning, traffic monitoring, and driver assistance. How to extract various road edges fast and robustly is a challenging task. In this paper, we present a fast and robust algorithm for the automatic road edges extraction from terrestrial mobile LiDAR data. The algorithm is based on a key observation: most roads around edges have difference in elevation and road edges with pavement are seen in two different planes. In our algorithm, we firstly extract a rough plane based on RANSAC algorithm, and then multiple refined planes which only contains pavement are extracted from the rough plane. The road edges are extracted based on these refined planes. In practice, there is a serious problem that the rough and refined planes usually extracted badly due to rough roads and different density of point cloud. To eliminate the influence of rough roads, the technology which is similar with the difference of DSM (digital surface model and DTM (digital terrain model is used, and we also propose a method which adjust the point clouds to a similar density to eliminate the influence of different density. Experiments show the validities of the proposed method with multiple datasets (e.g. urban road, highway, and some rural road. We use the same parameters through the experiments and our algorithm can achieve real-time processing speeds.
a Fast and Robust Algorithm for Road Edges Extraction from LIDAR Data
Qiu, Kaijin; Sun, Kai; Ding, Kou; Shu, Zhen
2016-06-01
Fast mapping of roads plays an important role in many geospatial applications, such as infrastructure planning, traffic monitoring, and driver assistance. How to extract various road edges fast and robustly is a challenging task. In this paper, we present a fast and robust algorithm for the automatic road edges extraction from terrestrial mobile LiDAR data. The algorithm is based on a key observation: most roads around edges have difference in elevation and road edges with pavement are seen in two different planes. In our algorithm, we firstly extract a rough plane based on RANSAC algorithm, and then multiple refined planes which only contains pavement are extracted from the rough plane. The road edges are extracted based on these refined planes. In practice, there is a serious problem that the rough and refined planes usually extracted badly due to rough roads and different density of point cloud. To eliminate the influence of rough roads, the technology which is similar with the difference of DSM (digital surface model) and DTM (digital terrain model) is used, and we also propose a method which adjust the point clouds to a similar density to eliminate the influence of different density. Experiments show the validities of the proposed method with multiple datasets (e.g. urban road, highway, and some rural road). We use the same parameters through the experiments and our algorithm can achieve real-time processing speeds.
Ito, Kazuaki; Nagata, Ryo; Iwasaki, Makoto; Matsui, Nobuyuki
This paper presents a novel Genetic Algorithm (GA)-based autonomous compensator design and position command shaping considering the stand vibration suppression for the fast-response and high-precision positioning of mechatronic systems. The positioning system is mainly composed of a robust 2-degrees-of-freedom (2DOF) controller based on the coprime factorization description. The feedback compensator based on H∞ design framework in the 2DOF controller ensures the robustness against the variations of resonant vibration mode. The feedforward compensator and position command, on the other hand, can be autonomously designed by the optimization capability of GA, in order to achieve the desired positioning performance and to suppress the machine stand vibration. The effectiveness of the proposed optimal design has been verified by experiments using a table drive system with ball screw.
Fast and robust extraction of hippocampus from MR images for diagnostics of Alzheimer's disease
DEFF Research Database (Denmark)
Lötjönen, Jyrki; Wolz, Robin; Koikkalainen, Juha
2011-01-01
Assessment of temporal lobe atrophy from magnetic resonance images is a part of clinical guidelines for the diagnosis of prodromal Alzheimer's disease. As hippocampus is known to be among the first areas affected by the disease, fast and robust definition of hippocampus volume would be of great...... index, 0.87, and correlation coefficient, 0.94, with semi-automatically generated segmentations. When comparing hippocampus volumes extracted from 1.5T and 3T images, the absolute value of the difference was low: 3.2% of the volume. The correct classification rate for Alzheimer's disease and cognitively...
Robust stabilization of underactuated nonlinear systems: A fast terminal sliding mode approach.
Khan, Qudrat; Akmeliawati, Rini; Bhatti, Aamer Iqbal; Khan, Mahmood Ashraf
2017-01-01
This paper presents a fast terminal sliding mode based control design strategy for a class of uncertain underactuated nonlinear systems. Strategically, this development encompasses those electro-mechanical underactuated systems which can be transformed into the so-called regular form. The novelty of the proposed technique lies in the hierarchical development of a fast terminal sliding attractor design for the considered class. Having established sliding mode along the designed manifold, the close loop dynamics become finite time stable which, consequently, result in high precision. In addition, the adverse effects of the chattering phenomenon are reduced via strong reachability condition and the robustness of the system against uncertainties is confirmed theoretically. A simulation as well as experimental study of an inverted pendulum is presented to demonstrate the applicability of the proposed technique.
Bucki, Marek; Payan, Yohan; 10.1016/j.media.2010.02.003
2010-01-01
Finite Element mesh generation remains an important issue for patient specific biomechanical modeling. While some techniques make automatic mesh generation possible, in most cases, manual mesh generation is preferred for better control over the sub-domain representation, element type, layout and refinement that it provides. Yet, this option is time consuming and not suited for intraoperative situations where model generation and computation time is critical. To overcome this problem we propose a fast and automatic mesh generation technique based on the elastic registration of a generic mesh to the specific target organ in conjunction with element regularity and quality correction. This Mesh-Match-and-Repair (MMRep) approach combines control over the mesh structure along with fast and robust meshing capabilities, even in situations where only partial organ geometry is available. The technique was successfully tested on a database of 5 pre-operatively acquired complete femora CT scans, 5 femoral heads partially...
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rizzuto, Enrico; Narasimhan, Harikrishna
2012-01-01
More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of structures......, a theoretical and risk-based framework is presented which facilitates the quantification of robustness, and thus supports the formulation of pre-normative guidelines....
A Robust and Fast Non-Local Means Algorithm for Image Denoising
Institute of Scientific and Technical Information of China (English)
Yan-Li Liu; Jin Wang; Xi Chen; Yan-Wen Guo; Qun-Sheng Peng
2008-01-01
In the paper, we propose a robust and fast image denoising method. The approach integrates both Non- Local means algorithm and Laplacian Pyramid. Given an image to be denoised, we first decompose it into Laplacian pyramid. Exploiting the redundancy property of Laplacian pyramid, we then perform non-local means on every level image of Laplacian pyramid. Essentially, we use the similarity of image features in Laplacian pyramid to act as weight to denoise image. Since the features extracted in Laplacian pyramid are localized in spatial position and scale, they are much more able to describe image, and computing the similarity between them is more reasonable and more robust. Also, based on the efficient Summed Square Image (SSI) scheme and Fast Fourier Transform (FFT), we present an accelerating algorithm to break the bottleneck of non-local means algorithm - similarity computation of compare windows. After speedup, our algorithm is fifty times faster than original non-local means algorithm. Experiments demonstrated the effectiveness of our algorithm.
Real-Time Robust Tracking for Motion Blur and Fast Motion via Correlation Filters
Xu, Lingyun; Luo, Haibo; Hui, Bin; Chang, Zheng
2016-01-01
Visual tracking has extensive applications in intelligent monitoring and guidance systems. Among state-of-the-art tracking algorithms, Correlation Filter methods perform favorably in robustness, accuracy and speed. However, it also has shortcomings when dealing with pervasive target scale variation, motion blur and fast motion. In this paper we proposed a new real-time robust scheme based on Kernelized Correlation Filter (KCF) to significantly improve performance on motion blur and fast motion. By fusing KCF and STC trackers, our algorithm also solve the estimation of scale variation in many scenarios. We theoretically analyze the problem for CFs towards motions and utilize the point sharpness function of the target patch to evaluate the motion state of target. Then we set up an efficient scheme to handle the motion and scale variation without much time consuming. Our algorithm preserves the properties of KCF besides the ability to handle special scenarios. In the end extensive experimental results on benchmark of VOT datasets show our algorithm performs advantageously competed with the top-rank trackers. PMID:27618046
Robust and fast license plate detection based on the fusion of color and edge feature
Cai, De; Shi, Zhonghan; Liu, Jin; Hu, Chuanping; Mei, Lin; Qi, Li
2014-11-01
Extracting a license plate is an important stage in automatic vehicle identification. The degradation of images and the computation intense make this task difficult. In this paper, a robust and fast license plate detection based on the fusion of color and edge feature is proposed. Based on the dichromatic reflection model, two new color ratios computed from the RGB color model are introduced and proved to be two color invariants. The global color feature extracted by the new color invariants improves the method's robustness. The local Sobel edge feature guarantees the method's accuracy. In the experiment, the detection performance is good. The detection results show that this paper's method is robust to the illumination, object geometry and the disturbance around the license plates. The method can also detect license plates when the color of the car body is the same as the color of the plates. The processing time for image size of 1000x1000 by pixels is nearly 0.2s. Based on the comparison, the performance of the new ratios is comparable to the common used HSI color model.
Fast and robust identification of single bacteria in environmental matrices by Raman spectroscopy
Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne-Catherine; Bourdat, Anne-Gaelle; Espagnon, Isabelle; Laurent, Patricia; Dinten, Jean-Marc
2015-03-01
We report on our recent results on robust identification of single bacterial cells embedded in various environments using Spontaneous Raman Scattering. Five species of bacteria were considered, two of which (B. Subtilis and E. Coli) were grown under various conditions, or embedded in two real-world matrices. We recorded the Raman spectra of single cells with a confocal instrument developed in our lab, and performed identification at the species level. Our system integrates a Lensfree imaging module that allows fast detection of bacteria over a large Field-Of-View. Identification rates comparable to those obtained on lab cultures were possible using a comprehensive database containing spectra from bacteria in all environments. In addition, B. Subtilis was correctly identified in 95.5% of the cases using a database composed exclusively of spectra obtained in standard conditions. This is very promising for pathogen threat detection where the construction of an exhaustive database may be challenging.
Huthwaite, P; Simonetti, F
2011-09-01
Breast ultrasound tomography has the potential to improve the cost, safety, and reliability of breast cancer screening and diagnosis over the gold-standard of mammography. Vital to achieving this potential is the development of imaging algorithms to unravel the complex anatomy of the breast and its mechanical properties. The solution most commonly relied upon is time-of-flight tomography, but this exhibits low resolution due to the presence of diffraction effects. Iterative full-wave inversion methods present one solution to achieve higher resolution, but these are slow and are not guaranteed to converge to the correct solution. Presented here is HARBUT, the hybrid algorithm for robust breast ultrasound tomography, which utilizes the complementary strengths of time-of-flight and diffraction tomography resulting in a direct, fast, robust and accurate high resolution method of reconstructing the sound speed through the breast. The algorithm is shown to produce accurate reconstructions with realistic data from a complex three-dimensional simulation, with masses as small as 4 mm being clearly visible.
SERF: A Simple, Effective, Robust, and Fast Image Super-Resolver From Cascaded Linear Regression.
Hu, Yanting; Wang, Nannan; Tao, Dacheng; Gao, Xinbo; Li, Xuelong
2016-09-01
Example learning-based image super-resolution techniques estimate a high-resolution image from a low-resolution input image by relying on high- and low-resolution image pairs. An important issue for these techniques is how to model the relationship between high- and low-resolution image patches: most existing complex models either generalize hard to diverse natural images or require a lot of time for model training, while simple models have limited representation capability. In this paper, we propose a simple, effective, robust, and fast (SERF) image super-resolver for image super-resolution. The proposed super-resolver is based on a series of linear least squares functions, namely, cascaded linear regression. It has few parameters to control the model and is thus able to robustly adapt to different image data sets and experimental settings. The linear least square functions lead to closed form solutions and therefore achieve computationally efficient implementations. To effectively decrease these gaps, we group image patches into clusters via k-means algorithm and learn a linear regressor for each cluster at each iteration. The cascaded learning process gradually decreases the gap of high-frequency detail between the estimated high-resolution image patch and the ground truth image patch and simultaneously obtains the linear regression parameters. Experimental results show that the proposed method achieves superior performance with lower time consumption than the state-of-the-art methods.
A Fast, Accurate and Robust Algorithm For Transferring Radiation in Three-Dimensional Space
Cen, R
2002-01-01
We have developed an algorithm for transferring radiation in three-dimensional space. The algorithm computes radiation source and sink terms using the Fast Fourier Transform (FFT) method, based on a formulation in which the integral of any quantity (such as emissivity or opacity) over any volume may be written in the classic convolution form. The algorithm is fast with the computational time scaling as N (log N)^2, where N is the number of grid points of a simulation box, independent of the number of radiation sources. Furthermore, in this formulation one can naturally account for both local radiation sources and diffuse background as well as any extra external sources, all in a completely self-consistent fashion. Finally, the algorithm is completely stable and robust. While the algorithm is generally applicable, we test it on a set of problems that encompass a wide range of situations in cosmological applications, demonstrating that the algorithm is accurate. These tests show that the algorithm produces resu...
Energy Technology Data Exchange (ETDEWEB)
Laroche, E. [Lab. des Sciences de l' Image, de l' Informatique et de la Teledetection, UMR 7005, Pole API, 67 - Illkirch (France); Mendes, E. [Laboratoire de Genie Electrique de Paris, UMR 8507, 91 - Gilf sur Yvette (France); Louis, J.P.; Bonnassieux, Y.; Abou-Kandil, H. [Laboratoire d' Electricite, Signaux et Robotique, UPRESA 8029, 94 - Cachan (France)
2002-07-01
In this paper is presented a method for tuning a robust controller well adapted for positioning a load of variable inertia fed by an electric actuator. This method relies on a multi-model pole assignment and minimizes effect of measurement noise. It has been implemented on the benchmark 'fast transitic' located at the LGEP. Thus compared to a classical pole assignment method, the gain of robustness has been shown. The actuator used is an induction machine with flux-oriented control, which is known for its sensitivity to rotor parameter estimation errors. In order to check robustness, a model accounting to this phenomenon is developed and stability margins are computed. (authors)
Measuring downside risk - realised semivariance
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole; Kinnebrock, Silja; Shephard, Neil
We propose a new measure of risk, based entirely on downwards moves measured using high frequency data. Realised semivariances are shown to have important predictive qualities for future market volatility. The theory of these new measures is spelt out, drawing on some new results from probability...
Fast and robust pushbroom hyperspectral imaging via DMD-based scanning
Arablouei, Reza; Gensemer, Stephen; Kusy, Branislav
2016-01-01
We describe a new pushbroom hyperspectral imaging device that has no macro moving part. The main components of the proposed hyperspectral imager are a digital micromirror device (DMD), a CMOS image sensor with no filter as the spectral sensor, a CMOS color (RGB) image sensor as the auxiliary image sensor, and a diffraction grating. Using the image sensor pair, the device can simultaneously capture hyperspectral data as well as RGB images of the scene. The RGB images captured by the auxiliary image sensor can facilitate geometric co-registration of the hyperspectral image slices captured by the spectral sensor. In addition, the information discernible from the RGB images can lead to capturing the spectral data of only the regions of interest within the scene. The proposed hyperspectral imaging architecture is cost-effective, fast, and robust. It also enables a trade-off between resolution and speed. We have built an initial prototype based on the proposed design. The prototype can capture a hyperspectral image...
Definition of a Robust Supervisory Control Scheme for Sodium-Cooled Fast Reactors
Energy Technology Data Exchange (ETDEWEB)
Ponciroli, R.; Passerini, S.; Vilim, R. B.
2016-04-17
In this work, an innovative control approach for metal-fueled Sodium-cooled Fast Reactors is proposed. With respect to the classical approach adopted for base-load Nuclear Power Plants, an alternative control strategy for operating the reactor at different power levels by respecting the system physical constraints is presented. In order to achieve a higher operational flexibility along with ensuring that the implemented control loops do not influence the system inherent passive safety features, a dedicated supervisory control scheme for the dynamic definition of the corresponding set-points to be supplied to the PID controllers is designed. In particular, the traditional approach based on the adoption of tabulated lookup tables for the set-point definition is found not to be robust enough when failures of the implemented SISO (Single Input Single Output) actuators occur. Therefore, a feedback algorithm based on the Reference Governor approach, which allows for the optimization of reference signals according to the system operating conditions, is proposed.
Direct infusion-SIM as fast and robust method for absolute protein quantification in complex samples
Directory of Open Access Journals (Sweden)
Christina Looße
2015-06-01
Full Text Available Relative and absolute quantification of proteins in biological and clinical samples are common approaches in proteomics. Until now, targeted protein quantification is mainly performed using a combination of HPLC-based peptide separation and selected reaction monitoring on triple quadrupole mass spectrometers. Here, we show for the first time the potential of absolute quantification using a direct infusion strategy combined with single ion monitoring (SIM on a Q Exactive mass spectrometer. By using complex membrane fractions of Escherichia coli, we absolutely quantified the recombinant expressed heterologous human cytochrome P450 monooxygenase 3A4 (CYP3A4 comparing direct infusion-SIM with conventional HPLC-SIM. Direct-infusion SIM revealed only 14.7% (±4.1 (s.e.m. deviation on average, compared to HPLC-SIM and a decreased processing and analysis time of 4.5 min (that could be further decreased to 30 s for a single sample in contrast to 65 min by the LC–MS method. Summarized, our simplified workflow using direct infusion-SIM provides a fast and robust method for quantification of proteins in complex protein mixtures.
Fast and robust 3D ultrasound registration--block and game theoretic matching.
Banerjee, Jyotirmoy; Klink, Camiel; Peters, Edward D; Niessen, Wiro J; Moelker, Adriaan; van Walsum, Theo
2015-02-01
Real-time 3D US has potential for image guidance in minimally invasive liver interventions. However, motion caused by patient breathing makes it hard to visualize a localized area, and to maintain alignment with pre-operative information. In this work we develop a fast affine registration framework to compensate in real-time for liver motion/displacement due to breathing. The affine registration of two consecutive ultrasound volumes in time is performed using block-matching. For a set of evenly distributed points in one volume and their correspondences in the other volume, we propose a robust outlier rejection method to reject false matches. The inliers are then used to determine the affine transformation. The approach is evaluated on 13 4D ultrasound sequences acquired from 8 subjects. For 91 pairs of 3D ultrasound volumes selected from these sequences, a mean registration error of 1.8mm is achieved. A graphics processing unit (GPU) implementation runs the 3D US registration at 8 Hz.
Robust Modeling of Low-Cost MEMS Sensor Errors in Mobile Devices Using Fast Orthogonal Search
Directory of Open Access Journals (Sweden)
M. Tamazin
2013-01-01
Full Text Available Accessibility to inertial navigation systems (INS has been severely limited by cost in the past. The introduction of low-cost microelectromechanical system-based INS to be integrated with GPS in order to provide a reliable positioning solution has provided more wide spread use in mobile devices. The random errors of the MEMS inertial sensors may deteriorate the overall system accuracy in mobile devices. These errors are modeled stochastically and are included in the error model of the estimated techniques used such as Kalman filter or Particle filter. First-order Gauss-Markov model is usually used to describe the stochastic nature of these errors. However, if the autocorrelation sequences of these random components are examined, it can be determined that first-order Gauss-Markov model is not adequate to describe such stochastic behavior. A robust modeling technique based on fast orthogonal search is introduced to remove MEMS-based inertial sensor errors inside mobile devices that are used for several location-based services. The proposed method is applied to MEMS-based gyroscopes and accelerometers. Results show that the proposed method models low-cost MEMS sensors errors with no need for denoising techniques and using smaller model order and less computation, outperforming traditional methods by two orders of magnitude.
Zhang, Mingjing; Wen, Ming; Zhang, Zhi-Min; Lu, Hongmei; Liang, Yizeng; Zhan, Dejian
2015-03-01
Retention time shift is one of the most challenging problems during the preprocessing of massive chromatographic datasets. Here, an improved version of the moving window fast Fourier transform cross-correlation algorithm is presented to perform nonlinear and robust alignment of chromatograms by analyzing the shifts matrix generated by moving window procedure. The shifts matrix in retention time can be estimated by fast Fourier transform cross-correlation with a moving window procedure. The refined shift of each scan point can be obtained by calculating the mode of corresponding column of the shifts matrix. This version is simple, but more effective and robust than the previously published moving window fast Fourier transform cross-correlation method. It can handle nonlinear retention time shift robustly if proper window size has been selected. The window size is the only one parameter needed to adjust and optimize. The properties of the proposed method are investigated by comparison with the previous moving window fast Fourier transform cross-correlation and recursive alignment by fast Fourier transform using chromatographic datasets. The pattern recognition results of a gas chromatography mass spectrometry dataset of metabolic syndrome can be improved significantly after preprocessing by this method. Furthermore, the proposed method is available as an open source package at https://github.com/zmzhang/MWFFT2.
WATSFAR: numerical simulation of soil WATer and Solute fluxes using a FAst and Robust method
Crevoisier, David; Voltz, Marc
2013-04-01
To simulate the evolution of hydro- and agro-systems, numerous spatialised models are based on a multi-local approach and improvement of simulation accuracy by data-assimilation techniques are now used in many application field. The latest acquisition techniques provide a large amount of experimental data, which increase the efficiency of parameters estimation and inverse modelling approaches. In turn simulations are often run on large temporal and spatial domains which requires a large number of model runs. Eventually, despite the regular increase in computing capacities, the development of fast and robust methods describing the evolution of saturated-unsaturated soil water and solute fluxes is still a challenge. Ross (2003, Agron J; 95:1352-1361) proposed a method, solving 1D Richards' and convection-diffusion equation, that fulfil these characteristics. The method is based on a non iterative approach which reduces the numerical divergence risks and allows the use of coarser spatial and temporal discretisations, while assuring a satisfying accuracy of the results. Crevoisier et al. (2009, Adv Wat Res; 32:936-947) proposed some technical improvements and validated this method on a wider range of agro- pedo- climatic situations. In this poster, we present the simulation code WATSFAR which generalises the Ross method to other mathematical representations of soil water retention curve (i.e. standard and modified van Genuchten model) and includes a dual permeability context (preferential fluxes) for both water and solute transfers. The situations tested are those known to be the less favourable when using standard numerical methods: fine textured and extremely dry soils, intense rainfall and solute fluxes, soils near saturation, ... The results of WATSFAR have been compared with the standard finite element model Hydrus. The analysis of these comparisons highlights two main advantages for WATSFAR, i) robustness: even on fine textured soil or high water and solute
A Fast and Robust Poisson-Boltzmann Solver Based on Adaptive Cartesian Grids
Boschitsch, Alexander H.; Fenley, Marcia O.
2011-01-01
An adaptive Cartesian grid (ACG) concept is presented for the fast and robust numerical solution of the 3D Poisson-Boltzmann Equation (PBE) governing the electrostatic interactions of large-scale biomolecules and highly charged multi-biomolecular assemblies such as ribosomes and viruses. The ACG offers numerous advantages over competing grid topologies such as regular 3D lattices and unstructured grids. For very large biological molecules and multi-biomolecule assemblies, the total number of grid-points is several orders of magnitude less than that required in a conventional lattice grid used in the current PBE solvers thus allowing the end user to obtain accurate and stable nonlinear PBE solutions on a desktop computer. Compared to tetrahedral-based unstructured grids, ACG offers a simpler hierarchical grid structure, which is naturally suited to multigrid, relieves indirect addressing requirements and uses fewer neighboring nodes in the finite difference stencils. Construction of the ACG and determination of the dielectric/ionic maps are straightforward, fast and require minimal user intervention. Charge singularities are eliminated by reformulating the problem to produce the reaction field potential in the molecular interior and the total electrostatic potential in the exterior ionic solvent region. This approach minimizes grid-dependency and alleviates the need for fine grid spacing near atomic charge sites. The technical portion of this paper contains three parts. First, the ACG and its construction for general biomolecular geometries are described. Next, a discrete approximation to the PBE upon this mesh is derived. Finally, the overall solution procedure and multigrid implementation are summarized. Results obtained with the ACG-based PBE solver are presented for: (i) a low dielectric spherical cavity, containing interior point charges, embedded in a high dielectric ionic solvent – analytical solutions are available for this case, thus allowing rigorous
A fast-and-robust profiler for improving polymerase chain reaction diagnostics.
Directory of Open Access Journals (Sweden)
George J Besseris
Full Text Available Polymerase chain reaction (PCR is an in vitro technology in molecular genetics that progressively amplifies minimal copies of short DNA sequences in a fast and inexpensive manner. However, PCR performance is sensitive to suboptimal processing conditions. Compromised PCR conditions lead to artifacts and bias that downgrade the discriminatory power and reproducibility of the results. Promising attempts to resolve the PCR performance optimization issue have been guided by quality improvement tactics adopted in the past for industrial trials. Thus, orthogonal arrays (OAs have been employed to program quick-and-easy structured experiments. Profiling of influences facilitates the quantification of effects that may counteract the detectability of amplified DNA fragments. Nevertheless, the attractive feature of reducing greatly the amount of work and expenditures by planning trials with saturated-unreplicated OA schemes is known to be relinquished in the subsequent analysis phase. This is because of an inherent incompatibility of ordinary multi-factorial comparison techniques to convert small yet dense datasets. Treating unreplicated-saturated data with either the analysis of variance (ANOVA or regression models destroys the information extraction process. Both of those mentioned approaches are rendered blind to error since the examined effects absorb all available degrees of freedom. Therefore, in lack of approximating an experimental uncertainty, any outcome interpretation is rendered subjective. We propose a profiling method that permits the non-linear maximization of amplicon resolution by eliminating the necessity for direct error estimation. Our approach is distribution-free, calibration-free, simulation-free and sparsity-free with well-known power properties. It is also user-friendly by promoting rudimentary analytics. Testing our method on published amplicon count data, we found that the preponderant effect is the concentration of MgCl2 (p0
Robust and fast abdominal aortic aneurysm centerline detection for rupture risk prediction
Zhang, Hong; Finol, Ender A.
2011-03-01
This work describes a robust and fast semi-automatic approach for Abdominal Aortic Aneurysm (AAA) centerline detection. AAA is a vascular disease accompanied by progressive enlargement of the abdominal aorta, which leads to rupture if left untreated, an event that accounts for the 13th leading cause of death in the U.S. The lumen centerline can be used to provide the initial starting points for thrombus segmentation. Different from other methods, which are mostly based on region growing and suffer from problems of leakage and heavy computational burden, we propose a novel method based on online classification. An online version of the adaboost classifier based on steerable features is applied to AAA MRI data sets with a rectangular box enclosing the lumen in the first slice. The classifier is updated during the tracking process by using the testing result of the previous image as the new training data. Unlike traditional offline versions, the online classifier can adjust parameters automatically when a leakage occurs. With the help of integral images on the computation of haar-like features, the method can achieve nearly real time processing (about 2 seconds per image on a standard workstation). Ten ruptured and ten unruptured AAA data sets were processed and the tortuosity of the 20 centerlines was calculated. The correlation coefficient of the tortuosity was calculated to illustrate the significance of the prediction with the proposed method. The mean relative accuracy is 95.68% with a standard deviation of 0.89% when compared to a manual segmentation procedure. The correlation coefficient is 0.394.
一种快速鲁棒的LOG-FAST角点算法%Fast and Robust LOG-FAST Corner Algorithm
Institute of Scientific and Technical Information of China (English)
梁艳菊; 李庆; 陈大鹏; 颜学究
2012-01-01
Based on time-efficient FAST algorithm, the paper described a fast and robust LOG-FAST corner algorithm. Histogram equalization as one kind of image enhancement was firstly applied to the original image for sharpening useful image information and improving image illumination invariance. Then Laplacian of Gaussian operator was convoluted to achieve image guassian smooth and edge enhancement,and also suppress noise in the maximal degree. At last,FAST algorithm was applied to produce LOG-FAST corners. The new corner detection algorithm not only features with time^ef-ficient as FAST algorithm, also has illumination invariant, noise invariant and robust feature. Experiments show that LOG-FAST algorithm can achieve a detection time 0. 05s on noised images sized with 640 * 480. It has the similar detection performance on illuminate variant images and has repeatability 98 percent. Due to its excellent performance, LOG-FAST algorithm can be used in real time video process applications such as intelligent vehicle warning system.%基于高时间效率的FAST算法,提出了一种快速鲁棒的FAST-LOG角点算法.使用直方图均衡化方法对图像进行增强,提高图像成分的清晰度并消除图像中光照强度的影响;运用拉普拉斯-高斯函数对图像进行卷积,实现图像的高斯平滑和增强边缘,及对噪声最大化的抑制；最后使用FAST算子检测角点.对比实验证明,新算子对于添加高斯噪声的分辨率为640 * 480的图像,其检测时间可达到0.05s；对光照不同的图像具有相近的检测性能；角点重复率可达98％.该算子可应用于实时视频图像的处理,为开发基于视觉的实时智能车辆预警系统提供了新的研究思路.
F2DPR: a fast and robust cross-correlation technique for volumetric PIV
Earl, Thomas; Jeon, Young Jin; Lecordier, Bertrand; David, Laurent
2016-08-01
The current state-of-the-art in cross-correlation based time-resolved particle image velocimetry (PIV) techniques are the fluid trajectory correlation, FTC (Lynch and Scarano 2013) and the fluid trajectory evaluation based on an ensemble-averaged cross-correlation, FTEE (Jeon et al 2014a). These techniques compute the velocity vector as a polynomial trajectory Γ in space and time, enabling the extraction of beneficial quantities such as material acceleration whilst significantly increasing the accuracy of the particle displacement prediction achieved by standard two-frame PIV. In the context of time-resolved volumetric PIV, the drawback of trajectory computation is the computational expense of the three-dimensional (3D) cross-correlation, exacerbated by the requirement to perform N - 1 cross-correlations, where N (for typically 5≤slant N≤slant 9 ) is the number of sequential particle volumes, for each velocity field. Therefore, the acceleration of this calculation is highly desirable. This paper re-examines the application of two-dimensional (2D) cross-correlation methods to three-dimensional (3D) datasets by Bilsky et al (2011) and the binning techniques of Discetti and Astarita (2012). A new and robust version of the 2D methods is proposed and described, called fast 2D projection—re-projection (f2dpr). Performance tests based on computational time and accuracy for both two-frame and multi-frame PIV are carried out on synthetically generated data. The cases presented herein include uniaxial uniform linear displacements and shear, and simulated turbulence data. The proposed algorithm is shown to be in the order of 10 times faster than a standard 3D FFT without loss of precision for a wide range of synthetic test cases, while combining with the binning technique can yield 50 times faster computation. The algorithm is also applied to reconstructed synthetic turbulent particle fields to investigate reconstruction noise on its performance and no
Scatterometry—fast and robust measurements of nano-textured surfaces
Hannibal Madsen, Morten; Hansen, Poul-Erik
2016-06-01
Scatterometry is a fast, precise and low cost way to determine the mean pitch and dimensional parameters of periodic structures with lateral resolution of a few nanometer. It is robust enough for in-line process control and precise and accurate enough for metrology measurements. Furthermore, scatterometry is a non-destructive technique capable of measuring buried structures, for example a grating covered by a thick oxide layer. As scatterometry is a non-imaging technique, mathematical modeling is needed to retrieve structural parameters that describe a surface. In this review, the three main steps of scatterometry are discussed: the data acquisition, the simulation of diffraction efficiencies and the comparison of data and simulations. First, the intensity of the diffracted light is measured with a scatterometer as a function of incoming angle, diffraction angle and/or wavelength. We discuss the evolution of the scatterometers from the earliest angular scatterometers to the new imaging scatterometers. The basic principle of measuring diffraction efficiencies in scatterometry has remained the same since the beginning, but the instrumental improvements have made scatterometry a state-of-the-art solution for fast and accurate measurements of nano-textured surfaces. The improvements include extending the wavelength range from the visible to the extreme ultra-violet range, development of Fourier optics to measure all diffraction orders simultaneously, and an imaging scatterometer to measure area of interests smaller than the spot size. Secondly, computer simulations of the diffraction efficiencies are discussed with emphasis on the rigorous coupled-wave analysis (RCWA) method. RCWA has, since the mid-1990s, been the preferred method for grating simulations due to the speed of the algorithms. In the beginning the RCWA method suffered from a very slow convergence rate, and we discuss the historical improvements to overcome this challenge, e.g. by the introduction of Li
Fast and Robust Control of Excitation Systems:A Finite-time Method
Institute of Scientific and Technical Information of China (English)
WANG Yu-zhen; CHENG Dai-zhan; HONG Yi-guang; QIN Hua-shu
2001-01-01
Using finite-time control approach, this paper proposes a new design method for nonlinear robust excitation control of a widely used 5th-order model of synchronous generators. The finite-time excitation controller achieved here can improve the system's behaviors in some aspects such as quick convergence and robustness for uncertainties. Simulations demonstrate that the finite-time excitation controller is more effective than some other excitation controllers.
DEFF Research Database (Denmark)
McCloskey, Douglas; Utrilla, Jose; Naviaux, Robert K.;
2015-01-01
of a suitable method for anaerobic cultures grown in complex media. Given that a vast majority of bacteria are facultative or obligate anaerobes that grow to low biomass density and need to be cultured in complex media, a suitable sampling and extraction strategy for anaerobic cultures is needed. In this work......Liquid chromatography tandem mass spectrometry (LC–MS/MS) provides a powerful means to analyze intracellular metabolism. A prerequisite to accurate metabolomics analysis using LC–MS/MS is a robust sampling and extraction protocol. One unaddressed area in sampling is a detailed examination......, we develop a fast-filtration method using pressuredriven Swinnex filters. We show that the method is fast enough to provide an accurate snapshot of intracellular metabolism, reduces matrix interference from the media to improve the number of compounds that can be detected, and is applicable...
DEFF Research Database (Denmark)
Harbo, Anders La-Cour; Stoustrup, Jakob
2002-01-01
We present a signal processing algorithm for making robust and simultaneous measurements in an active sensor, which has one or more emitters and a receiver, and which employs some sort of signal processing hardware. Robustness means low sensitivity to time and frequency localized disturbances...... on previously transmitted signals. This also means that only few calculations are needed. Furthermore, the suggested spread spectrum transform has a low complexity, a high numerical stability, and is easily implemented in simple signal processing hardware. The presented method is therefore suitable for low-cost...
Touati, F.; Idres, M.; Kahlouche, S.
2010-12-01
A method is presented for the fast and robust computation of the spherical harmonic coefficients of the terrestrial gravitational field from precise kinematic orbit of GOCE satellite. To reduce the influence of outliers in the kinematic orbit, Huber's M-estimation is applied. The computational aspect of this method is studied with great importance by investigating the Newton's procedure which converges faster than the iteratively reweighted least squares (IRLS) algorithm. The processing strategy of the orbit data is based on satellite accelerations, which are derived from GPS position time-series by Newton's interpolation. The gradient of the gravitational potential with respect to rectangular coordinates is expressed using the Cunningham-Metris method. The Newton's law of motion performs the equality between satellite accelerations and the gradient of the gravitational potential in an inertial frame system. Numerical results using simulated data are realized in order to test the robustness and the computational efficiency of the proposed method.
Morii, Youhi; Terashima, Hiroshi; Koshi, Mitsuo; Shimizu, Taro; Shima, Eiji
2016-10-01
We herein propose a fast and robust Jacobian-free time integration method named as the extended robustness-enhanced numerical algorithm (ERENA) to treat the stiff ordinary differential equations (ODEs) of chemical kinetics. The formulation of ERENA is based on an exact solution of a quasi-steady-state approximation that is optimized to preserve the mass conservation law through use of a Lagrange multiplier method. ERENA exhibits higher accuracy and faster performance in homogeneous ignition simulations compared to existing popular explicit and implicit methods for stiff ODEs such as VODE, MTS, and CHEMEQ2. We investigate the effects of user-specified threshold values in ERENA, to provide trade-off information between the accuracy and the computational cost.
DEFF Research Database (Denmark)
Hagberg, Emma Elisabeth; Krarup, Anders; Fahnøe, Ulrik;
2016-01-01
have focused on limited regions of the viral genome. This paper describes a robust, reliable, and fast protocol for amplification of the full AMDV genome using long-range PCR. The method was used to generate next generation sequencing data for the non-virulent cell-culture adapted AMDV-G strain as well......Aleutian Mink Disease Virus (AMDV) is a frequently encountered pathogen associated with commercial mink breeding. AMDV infection leads to increased mortality and compromised animal health and welfare. Currently little is known about the molecular evolution of the virus, and the few existing studies...
Balla-Arabé, Souleymane; Gao, Xinbo; Wang, Bin
2013-06-01
In the last decades, due to the development of the parallel programming, the lattice Boltzmann method (LBM) has attracted much attention as a fast alternative approach for solving partial differential equations. In this paper, we first designed an energy functional based on the fuzzy c-means objective function which incorporates the bias field that accounts for the intensity inhomogeneity of the real-world image. Using the gradient descent method, we obtained the corresponding level set equation from which we deduce a fuzzy external force for the LBM solver based on the model by Zhao. The method is fast, robust against noise, independent to the position of the initial contour, effective in the presence of intensity inhomogeneity, highly parallelizable and can detect objects with or without edges. Experiments on medical and real-world images demonstrate the performance of the proposed method in terms of speed and efficiency.
Fast and Robust pointing and tracking using a second-generation star tracker
DEFF Research Database (Denmark)
Jørgensen, John Leif; Pickles, Andrew
1998-01-01
Second generation star trackers work by taking wide-angle optical pictures of star fields, correlating the image against a star catalogue in ROM, centroiding many stars to derive an accurate position and orientation. This paper describes a miniature instrument(10cm cube), fast and lightweight (85...
A Robust and Fast System for CTC Computer-Aided Detection of Colorectal Lesions
2010-01-01
We present a complete, end-to-end computer-aided detection (CAD) system for identifying lesions in the colon, imaged with computed tomography (CT). This system includes facilities for colon segmentation, candidate generation, feature analysis, and classification. The algorithms have been designed to offer robust performance to variation in image data and patient preparation. By utilizing efficient 2D and 3D processing, software optimizations, multi-threading, feature selection, and an optimiz...
Robust Vacuum-/Air-Dried Graphene Aerogels and Fast Recoverable Shape-Memory Hybrid Foams.
Li, Chenwei; Qiu, Ling; Zhang, Baoqing; Li, Dan; Liu, Chen-Yang
2016-02-17
New graphene aerogels can be fabricated by vacuum/air drying, and because of the mechanical robustness of the graphene aerogels, shape-memory polymer/graphene hybrid foams can be fabricated by a simple infiltration-air-drying-crosslinking method. Due to the superelasticity, high strength, and good electrical conductivity of the as-prepared graphene aerogels, the shape-memory hybrid foams exhibit excellent thermotropical and electrical shape-memory properties, outperforming previously reported shape-memory polymer foams.
Institute of Scientific and Technical Information of China (English)
Ping Lu; Xudong Jiang; Wei Lu; Ran Wei; Bin Sheng
2015-01-01
Regularized Boolean operations have been widely used in 3D modeling systems. However, evaluating Boolean operations may be quite numerically unstable and time consuming, espe⁃cially for iterated set operations. A novel and unified tech⁃nique is proposed in this paper for computing single and iter⁃ated set operations efficiently, robustly and exactly. An adap⁃tive octree is combined with a nested constructive solid geom⁃etry (CSG) tree by this technique. The intersection handling is restricted to the cells in the octree where intersection actu⁃ally occurs. Within those cells, a CSG tree template is in⁃stanced by the surfaces and the tree is converted to plane⁃based binary space partitioning (BSP) for set evaluation;More⁃over, the surface classification is restricted to the cells in the octree where the surfaces only come from a model and are within the bounding⁃boxes of other polyhedrons. These two ways bring about the efficiency and scalability of the opera⁃tions, in terms of runtime and memory. As all surfaces in such a cell have the same classification relation, they are clas⁃sified as a whole. Robustness and exactness are achieved by integrating plane⁃based geometry representation with adaptive geometry predicate technique in intersection handling, and by applying divide⁃and⁃conquer arithmetic on surface classifica⁃tion. Experimental results demonstrate that the proposed ap⁃proach can guarantee the robustness of Boolean computations and runs faster than other existing approaches.
Directory of Open Access Journals (Sweden)
Ruben Gil-Solsona
2017-01-01
Full Text Available A metabolomic study has been performed to identify sensitive and robust biomarkers of malnutrition in farmed fish, using gilthead sea bream (Sparus aurata as a model. The metabolomic fingerprinting of serum from fasted fish was assessed by means of ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. More than 15,000 different m/z ions were detected and Partial Least Squares–Discriminant analysis allowed a clear differentiation between the two experimental groups (fed and 10-day fasted fish with more than 90% of total variance explained by the two first components. The most significant metabolites (up to 45 were elucidated on the basis of their tandem mass spectra with a broad representation of amino acids, oligopeptides, urea cycle metabolites, L-carnitine-related metabolites, glutathione-related metabolites, fatty acids, lysophosphatidic acids, phosphatidylcholines as well as biotin- and noradrenaline-related metabolites. This untargeted approach highlighted important adaptive responses in energy and oxidative metabolism, contributing to identify robust and nutritionally-regulated biomarkers of health and metabolic condition that will serve to assess the welfare status of farmed fish.
Huo, Guanying; Yang, Simon X; Li, Qingwu; Zhou, Yan
2017-04-01
Sidescan sonar image segmentation is a very important issue in underwater object detection and recognition. In this paper, a robust and fast method for sidescan sonar image segmentation is proposed, which deals with both speckle noise and intensity inhomogeneity that may cause considerable difficulties in image segmentation. The proposed method integrates the nonlocal means-based speckle filtering (NLMSF), coarse segmentation using k -means clustering, and fine segmentation using an improved region-scalable fitting (RSF) model. The NLMSF is used before the segmentation to effectively remove speckle noise while preserving meaningful details such as edges and fine features, which can make the segmentation easier and more accurate. After despeckling, a coarse segmentation is obtained by using k -means clustering, which can reduce the number of iterations. In the fine segmentation, to better deal with possible intensity inhomogeneity, an edge-driven constraint is combined with the RSF model, which can not only accelerate the convergence speed but also avoid trapping into local minima. The proposed method has been successfully applied to both noisy and inhomogeneous sonar images. Experimental and comparative results on real and synthetic sonar images demonstrate that the proposed method is robust against noise and intensity inhomogeneity, and is also fast and accurate.
Realising social justice in public health law.
Fox, Marie; Thomson, Michael
2013-03-01
Law has played an important, but largely constitutive, role in the development of the public health enterprise. Thus, law has been central to setting up the institutions and offices of public health. The moral agenda has, however, been shaped to a much greater extent by bioethics. While social justice has been placed at the heart of this agenda, we argue that there has been little place within dominant conceptions of social justice for gender equity and women's interests which we see as crucial to a fully realised vision of social justice. We argue that, aside from particular interventions in the field of reproduction, public health practice tends to marginalise women-a claim we support by critically examining strategies to combat the HIV pandemic in sub-Saharan Africa. To counter the marginalisation of women's interests, this article argues that Amartya Sen's capabilities approach has much to contribute to the framing of public health law and policy. Sen's approach provides an evaluative and normative framework which recognises the importance of both gender and health equity to achieving social justice. We suggest that domestic law and international human rights provisions, in particular the emerging human right to health, offer mechanisms to promote capabilities, and foster a robust and inclusive conception of social justice.
Baranwal, Mayank; Gorugantu, Ram S.; Salapaka, Srinivasa M.
2015-08-01
This paper aims at control design and its implementation for robust high-bandwidth precision (nanoscale) positioning systems. Even though modern model-based control theoretic designs for robust broadband high-resolution positioning have enabled orders of magnitude improvement in performance over existing model independent designs, their scope is severely limited by the inefficacies of digital implementation of the control designs. High-order control laws that result from model-based designs typically have to be approximated with reduced-order systems to facilitate digital implementation. Digital systems, even those that have very high sampling frequencies, provide low effective control bandwidth when implementing high-order systems. In this context, field programmable analog arrays (FPAAs) provide a good alternative to the use of digital-logic based processors since they enable very high implementation speeds, moreover with cheaper resources. The superior flexibility of digital systems in terms of the implementable mathematical and logical functions does not give significant edge over FPAAs when implementing linear dynamic control laws. In this paper, we pose the control design objectives for positioning systems in different configurations as optimal control problems and demonstrate significant improvements in performance when the resulting control laws are applied using FPAAs as opposed to their digital counterparts. An improvement of over 200% in positioning bandwidth is achieved over an earlier digital signal processor (DSP) based implementation for the same system and same control design, even when for the DSP-based system, the sampling frequency is about 100 times the desired positioning bandwidth.
Learning local appearances with sparse representation for robust and fast visual tracking.
Bai, Tianxiang; Li, You-Fu; Zhou, Xiaolong
2015-04-01
In this paper, we present a novel appearance model using sparse representation and online dictionary learning techniques for visual tracking. In our approach, the visual appearance is represented by sparse representation, and the online dictionary learning strategy is used to adapt the appearance variations during tracking. We unify the sparse representation and online dictionary learning by defining a sparsity consistency constraint that facilitates the generative and discriminative capabilities of the appearance model. An elastic-net constraint is enforced during the dictionary learning stage to capture the characteristics of the local appearances that are insensitive to partial occlusions. Hence, the target appearance is effectively recovered from the corruptions using the sparse coefficients with respect to the learned sparse bases containing local appearances. In the proposed method, the dictionary is undercomplete and can thus be efficiently implemented for tracking. Moreover, we employ a median absolute deviation based robust similarity metric to eliminate the outliers and evaluate the likelihood between the observations and the model. Finally, we integrate the proposed appearance model with the particle filter framework to form a robust visual tracking algorithm. Experiments on benchmark video sequences show that the proposed appearance model outperforms the other state-of-the-art approaches in tracking performance.
Fast and robust road segmentation and obstacle map generation for autonomous navigation
CSIR Research Space (South Africa)
Senekal, FP
2009-11-01
Full Text Available . The lookup table is then used on the same dataset to determine the performance of the system. Although this process may introduce unfair bias into the system, we believe that such bias is minimal, since the process was applied to a set of similar (but... obstacle map is laid over the segmented image and an estimate is made of the likelihood of drivable region in each occupancy cell. The technique performs reasonably well and has the advantage that it is fast enough that it can be implemented on a...
ROBUST AND FAST FREQUENCY OFFSET ESTIMATION FOR OFDM BASED SATELLITE COMMUNICATION
Institute of Scientific and Technical Information of China (English)
Wei Li; Xu Youyun; Cai Yueming
2009-01-01
A pilot-aided Orthogonal Frequency Division Multiplexing (OFDM) frequency offset estimator designed for satellite communication system is proposed in the paper. The estimator focuses on the acquisition of the integer part of carrier frequency offset and the acquisition range is as large as the whole signal bandwidth. Making full use of the phase difference between received pilot and local referential pilot, a fast estimation is obtained. Compared with existing method, our method can also work well even in SNR as low as 0dB. Simulations verify the good performance of our method.
A Robust and Fast System for CTC Computer-Aided Detection of Colorectal Lesions
Directory of Open Access Journals (Sweden)
Gareth Beddoe
2010-01-01
Full Text Available We present a complete, end-to-end computer-aided detection (CAD system for identifying lesions in the colon, imaged with computed tomography (CT. This system includes facilities for colon segmentation, candidate generation, feature analysis, and classification. The algorithms have been designed to offer robust performance to variation in image data and patient preparation. By utilizing efficient 2D and 3D processing, software optimizations, multi-threading, feature selection, and an optimized cascade classifier, the CAD system quickly determines a set of detection marks. The colon CAD system has been validated on the largest set of data to date, and demonstrates excellent performance, in terms of its high sensitivity, low false positive rate, and computational efficiency.
Optimal Control for Fast and Robust Generation of Entangled States in Anisotropic Heisenberg Chains
Zhang, Xiong-Peng; Shao, Bin; Zou, Jian
2017-05-01
Motivated by some recent results of the optimal control (OC) theory, we study anisotropic XXZ Heisenberg spin-1/2 chains with control fields acting on a single spin, with the aim of exploring how maximally entangled state can be prepared. To achieve the goal, we use a numerical optimization algorithm (e.g., the Krotov algorithm, which was shown to be capable of reaching the quantum speed limit) to search an optimal set of control parameters, and then obtain OC pulses corresponding to the target fidelity. We find that the minimum time for implementing our target state depending on the anisotropy parameter Δ of the model. Finally, we analyze the robustness of the obtained results for the optimal fidelities and the effectiveness of the Krotov method under some realistic conditions.
Optimal Control for Fast and Robust Generation of Entangled States in Anisotropic Heisenberg Chains
Zhang, Xiong-Peng; Shao, Bin; Zou, Jian
2017-02-01
Motivated by some recent results of the optimal control (OC) theory, we study anisotropic XXZ Heisenberg spin-1/2 chains with control fields acting on a single spin, with the aim of exploring how maximally entangled state can be prepared. To achieve the goal, we use a numerical optimization algorithm (e.g., the Krotov algorithm, which was shown to be capable of reaching the quantum speed limit) to search an optimal set of control parameters, and then obtain OC pulses corresponding to the target fidelity. We find that the minimum time for implementing our target state depending on the anisotropy parameter Δ of the model. Finally, we analyze the robustness of the obtained results for the optimal fidelities and the effectiveness of the Krotov method under some realistic conditions.
Robust and fast pedestrian detection method for far-infrared automotive driving assistance systems
Liu, Qiong; Zhuang, Jiajun; Ma, Jun
2013-09-01
Despite considerable effort has been contributed to night-time pedestrian detection for automotive driving assistance systems recent years, robust and real-time pedestrian detection is by no means a trivial task and is still underway due to the moving cameras, uncontrolled outdoor environments, wide range of possible pedestrian presentations and the stringent performance criteria for automotive applications. This paper presents an alternative night-time pedestrian detection method using monocular far-infrared (FIR) camera, which includes two modules (regions of interest (ROIs) generation and pedestrian recognition) in a cascade fashion. Pixel-gradient oriented vertical projection is first proposed to estimate the vertical image stripes that might contain pedestrians, and then local thresholding image segmentation is adopted to generate ROIs more accurately within the estimated vertical stripes. A novel descriptor called PEWHOG (pyramid entropy weighted histograms of oriented gradients) is proposed to represent FIR pedestrians in recognition module. Specifically, PEWHOG is used to capture both the local object shape described by the entropy weighted distribution of oriented gradient histograms and its pyramid spatial layout. Then PEWHOG is fed to a three-branch structured classifier using support vector machines (SVM) with histogram intersection kernel (HIK). An off-line training procedure combining both the bootstrapping and early-stopping strategy is introduced to generate a more robust classifier by exploiting hard negative samples iteratively. Finally, multi-frame validation is utilized to suppress some transient false positives. Experimental results on FIR video sequences from various scenarios demonstrate that the presented method is effective and promising.
Evaluating the CDM-Robustness of the input buffer with very fast transmission line pulse
Kao, Tzu-Cheng; Lee, Jian-Hsing; Hung, Chung-Yu; Lien, Chen-Hsin; Su, Hung-Der
2015-02-01
In this paper, a scheme for how to utilize VFTLP (very fast transmission line pulse) data to design an input buffer circuit for CDM (charged-device model) ESD protection is reported. The impedance of the ESD device under VFTLP stress is nearly 120 Ω at the beginning of turn-on transient, and decreases with time toward 10 Ω prior to the voltage falling below 0 V. In this work, the fact that the dynamic-characteristic impedance of the ESD device under VFTLP testing is independent of the stress current is found. Since both VFTLP zapping and the CDM are nanosecond events, the dynamic-characteristic impedance of the ESD device can be used to evaluate the CDM threshold voltage of the input buffer based on the equivalent and simplified RLC circuit.
A fast and robust iris localization method based on texture segmentation
Cui, Jiali; Wang, Yunhong; Tan, Tieniu; Ma, Li; Sun, Zhenan
2004-08-01
With the development of the current networked society, personal identification based on biometrics has received more and more attention. Iris recognition has a satisfying performance due to its high reliability and non-invasion. In an iris recognition system, preprocessing, especially iris localization plays a very important role. The speed and performance of an iris recognition system is crucial and it is limited by the results of iris localization to a great extent. Iris localization includes finding the iris boundaries (inner and outer) and the eyelids (lower and upper). In this paper, we propose an iris localization algorithm based on texture segmentation. First, we use the information of low frequency of wavelet transform of the iris image for pupil segmentation and localize the iris with a differential integral operator. Then the upper eyelid edge is detected after eyelash is segmented. Finally, the lower eyelid is localized using parabolic curve fitting based on gray value segmentation. Extensive experimental results show that the algorithm has satisfying performance and good robustness.
A fast and Robust Algorithm for general inequality/equality constrained minimum time problems
Energy Technology Data Exchange (ETDEWEB)
Briessen, B. [Sandia National Labs., Albuquerque, NM (United States); Sadegh, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Mechanical Engineering
1995-12-01
This paper presents a new algorithm for solving general inequality/equality constrained minimum time problems. The algorithm`s solution time is linear in the number of Runge-Kutta steps and the number of parameters used to discretize the control input history. The method is being applied to a three link redundant robotic arm with torque bounds, joint angle bounds, and a specified tip path. It solves case after case within a graphical user interface in which the user chooses the initial joint angles and the tip path with a mouse. Solve times are from 30 to 120 seconds on a Hewlett Packard workstation. A zero torque history is always used in the initial guess, and the algorithm has never crashed, indicating its robustness. The algorithm solves for a feasible solution for large trajectory execution time t{sub f} and then reduces t{sub f} and then reduces t{sub f} by a small amount and re-solves. The fixed time re- solve uses a new method of finding a near-minimum-2-norm solution to a set of linear equations and inequalities that achieves quadratic convegence to a feasible solution of the full nonlinear problem.
Fast and robust ray casting algorithms for virtual X-ray imaging
Freud, N.; Duvauchelle, P.; Létang, J. M.; Babot, D.
2006-07-01
Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or γ-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation.
Fast and robust ray casting algorithms for virtual X-ray imaging
Energy Technology Data Exchange (ETDEWEB)
Freud, N. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: Nicolas.Freud@insa-lyon.fr; Duvauchelle, P. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Letang, J.M. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Babot, D. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)
2006-07-15
Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or {gamma}-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation.
HIFI-C: a robust and fast method for determining NMR couplings from adaptive 3D to 2D projections.
Cornilescu, Gabriel; Bahrami, Arash; Tonelli, Marco; Markley, John L; Eghbalnia, Hamid R
2007-08-01
We describe a novel method for the robust, rapid, and reliable determination of J couplings in multi-dimensional NMR coupling data, including small couplings from larger proteins. The method, "High-resolution Iterative Frequency Identification of Couplings" (HIFI-C) is an extension of the adaptive and intelligent data collection approach introduced earlier in HIFI-NMR. HIFI-C collects one or more optimally tilted two-dimensional (2D) planes of a 3D experiment, identifies peaks, and determines couplings with high resolution and precision. The HIFI-C approach, demonstrated here for the 3D quantitative J method, offers vital features that advance the goal of rapid and robust collection of NMR coupling data. (1) Tilted plane residual dipolar couplings (RDC) data are collected adaptively in order to offer an intelligent trade off between data collection time and accuracy. (2) Data from independent planes can provide a statistical measure of reliability for each measured coupling. (3) Fast data collection enables measurements in cases where sample stability is a limiting factor (for example in the presence of an orienting medium required for residual dipolar coupling measurements). (4) For samples that are stable, or in experiments involving relatively stronger couplings, robust data collection enables more reliable determinations of couplings in shorter time, particularly for larger biomolecules. As a proof of principle, we have applied the HIFI-C approach to the 3D quantitative J experiment to determine N-C' RDC values for three proteins ranging from 56 to 159 residues (including a homodimer with 111 residues in each subunit). A number of factors influence the robustness and speed of data collection. These factors include the size of the protein, the experimental set up, and the coupling being measured, among others. To exhibit a lower bound on robustness and the potential for time saving, the measurement of dipolar couplings for the N-C' vector represents a realistic
Mokhtar, Hatem I; Abdel-Salam, Randa A; Haddad, Ghada M
2015-06-19
Robustness of RP-HPLC methods is a crucial method quality attribute which has gained an increasing interest throughout the efforts to apply quality by design concepts in analytical methodology. Improvement to design space modeling approaches to represent method robustness was the goal of many previous works. Modeling of design spaces regarding to method robustness fulfils quality by design essence of ensuring method validity throughout the design space. The current work aimed to describe an improvement to robustness modeling of design spaces in context of RP-HPLC method development for screening of eight antidiabetic drugs. The described improvement consisted of in-silico simulation of practical robustness testing procedures thus had the advantage of modeling design spaces with higher confidence in estimated of method robustness. The proposed in-silico robustness test was performed as a full factorial design of simulated method conditions deliberate shifts for each predicted point in knowledge space with modeling error propagation. Design space was then calculated as zones exceeding a threshold probability to pass the simulated robustness testing. Potential design spaces were mapped for three different stationary phases as a function of gradient elution parameters, pH and ternary solvent ratio. A robust and fast separation for the eight compounds within less than 6 min was selected and confirmed through experimental robustness testing. The effectiveness of this approach regarding definition of design spaces with ensured robustness and desired objectives was demonstrated.
Energy Technology Data Exchange (ETDEWEB)
Hamdi, A
2004-07-01
The new generation of light sources based on SASE Free-Electron-Lasers driven by LINACs operate with electron beams with high beam currents and duty cycles. This is especially true for the superconducting machines like TTF 2 and the X-RAY FEL, under construction or planning at DESY. Elaborate fast protections systems are required not only to protect the machine from electron beams hitting and destroying the vacuum chamber, but also to prevent the machine from running at high loss levels, dangerous for components like the FEL undulator. This document presents the different protection systems currently under construction for TTF 2. The very fast systems, based on transmission measurements and distributed loss detection monitors, are described in detail. This description includes the fast electronics to collect and to transmit the different interlock and status signals: analog to digital converters, DSP and FPGA, interfaces, toroid protection system (TPS) card. The implementation and validation (simulation and tests) of the TPS card at DESY is presented.
Gorban, A N; Mirkes, E M; Zinovyev, A
2016-12-01
Most of machine learning approaches have stemmed from the application of minimizing the mean squared distance principle, based on the computationally efficient quadratic optimization methods. However, when faced with high-dimensional and noisy data, the quadratic error functionals demonstrated many weaknesses including high sensitivity to contaminating factors and dimensionality curse. Therefore, a lot of recent applications in machine learning exploited properties of non-quadratic error functionals based on L1 norm or even sub-linear potentials corresponding to quasinorms Lp (0basic universal data approximation algorithms (k-means, principal components, principal manifolds and graphs, regularized and sparse regression), based on piece-wise quadratic error potentials of subquadratic growth (PQSQ potentials). We develop a new and universal framework to minimize arbitrary sub-quadratic error potentials using an algorithm with guaranteed fast convergence to the local or global error minimum. The theory of PQSQ potentials is based on the notion of the cone of minorant functions, and represents a natural approximation formalism based on the application of min-plus algebra. The approach can be applied in most of existing machine learning methods, including methods of data approximation and regularized and sparse regression, leading to the improvement in the computational cost/accuracy trade-off. We demonstrate that on synthetic and real-life datasets PQSQ-based machine learning methods achieve orders of magnitude faster computational performance than the corresponding state-of-the-art methods, having similar or better approximation accuracy. Copyright © 2016 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Lucie Pinasseau
2016-10-01
Full Text Available A rapid, sensitive, and selective analysis method using ultra high performance liquid chromatography coupled with triple-quadrupole mass spectrometry (UHPLC-QqQ-MS has been developed for the characterization and quantification of grape skin flavan-3-ols after acid-catalysed depolymerization in the presence of phloroglucinol (phloroglucinolysis. The compound detection being based on specific MS transitions in Multiple Reaction Monitoring (MRM mode, this fast gradient robust method allows analysis of constitutive units of grape skin proanthocyanidins, including some present in trace amounts, in a single injection, with a throughput of 6 samples per hour. This method was applied to a set of 214 grape skin samples from 107 different red and white grape cultivars grown under two conditions in the vineyard, irrigated or non-irrigated. The results of triplicate analyses confirmed the robustness of the method, which was thus proven to be suitable for high-throughput and large-scale metabolomics studies. Moreover, these preliminary results suggest that analysis of tannin composition is relevant to investigate the genetic bases of grape response to drought.
Bohoudi, O; Bruynzeel, A M E; Senan, S; Cuijpers, J P; Slotman, B J; Lagerwaard, F J; Palacios, M A
2017-08-12
To implement a robust and fast stereotactic MR-guided adaptive radiation therapy (SMART) online strategy in locally advanced pancreatic cancer (LAPC). SMART strategy for plan adaptation was implemented with the MRIdian system (ViewRay Inc.). At each fraction, OAR (re-)contouring is done within a distance of 3cm from the PTV surface. Online plan re-optimization is based on robust prediction of OAR dose and optimization objectives, obtained by building an artificial neural network (ANN). Proposed limited re-contouring strategy for plan adaptation (SMART3CM) is evaluated by comparing 50 previously delivered fractions against a standard (re-)planning method using full-scale OAR (re-)contouring (FULLOAR). Plan quality was assessed using PTV coverage (V95%, Dmean, D1cc) and institutional OAR constraints (e.g. V33Gy). SMART3CM required a significant lower number of optimizations than FULLOAR (4 vs 18 on average) to generate a plan meeting all objectives and institutional OAR constraints. PTV coverage with both strategies was identical (mean V95%=89%). Adaptive plans with SMART3CM exhibited significant lower intermediate and high doses to all OARs than FULLOAR, which also failed in 36% of the cases to adhere to the V33Gy dose constraint. SMART3CM approach for LAPC allows good OAR sparing and adequate target coverage while requiring only limited online (re-)contouring from clinicians. Copyright © 2017 Elsevier B.V. All rights reserved.
Tabus, I; Petrescu, D; Gabbouj, M
1996-01-01
A training framework is developed in this paper to design optimal nonlinear filters for various signal and image processing tasks. The targeted families of nonlinear filters are the Boolean filters and stack filters. The main merit of this framework at the implementation level is perhaps the absence of constraining models, making it nearly universal in terms of application areas. We develop fast procedures to design optimal or close to optimal filters, based on some representative training set. Furthermore, the training framework shows explicitly the essential part of the initial specification and how it affects the resulting optimal solution. Symmetry constraints are imposed on the data and, consequently, on the resulting optimal solutions for improved performance and ease of implementation. The case study is dedicated to natural images. The properties of optimal Boolean and stack filters, when the desired signal in the training set is the image of a natural scene, are analyzed. Specifically, the effect of changing the desired signal (using various natural images) and the characteristics of the noise (the probability distribution function, the mean, and the variance) is analyzed. Elaborate experimental conditions were selected to investigate the robustness of the optimal solutions using a sensitivity measure computed on data sets. A remarkably low sensitivity and, consequently, a good generalization power of Boolean and stack filters are revealed. Boolean-based filters are thus shown to be not only suitable for image restoration but also robust, making it possible to build libraries of "optimal" filters, which are suitable for a set of applications.
A fast and robust protocol for metataxonomic analysis using RNAseq data.
Cox, Jeremy W; Ballweg, Richard A; Taft, Diana H; Velayutham, Prakash; Haslam, David B; Porollo, Aleksey
2017-01-19
Metagenomics is a rapidly emerging field aimed to analyze microbial diversity and dynamics by studying the genomic content of the microbiota. Metataxonomics tools analyze high-throughput sequencing data, primarily from 16S rRNA gene sequencing and DNAseq, to identify microorganisms and viruses within a complex mixture. With the growing demand for analysis of the functional microbiome, metatranscriptome studies attract more interest. To make metatranscriptomic data sufficient for metataxonomics, new analytical workflows are needed to deal with sparse and taxonomically less informative sequencing data. We present a new protocol, IMSA+A, for accurate taxonomy classification based on metatranscriptome data of any read length that can efficiently and robustly identify bacteria, fungi, and viruses in the same sample. The new protocol improves accuracy by using a conservative reference database, employing a new counting scheme, and by assembling shotgun reads. Assembly also reduces analysis runtime. Simulated data were utilized to evaluate the protocol by permuting common experimental variables. When applied to the real metatranscriptome data for mouse intestines colonized by ASF, the protocol showed superior performance in detection of the microorganisms compared to the existing metataxonomics tools. IMSA+A is available at https://github.com/JeremyCoxBMI/IMSA-A . The developed protocol addresses the need for taxonomy classification from RNAseq data. Previously not utilized, i.e., unmapped to a reference genome, RNAseq reads can now be used to gather taxonomic information about the microbiota present in a biological sample without conducting additional sequencing. Any metatranscriptome pipeline that includes assembly of reads can add this analysis with minimal additional cost of compute time. The new protocol also creates an opportunity to revisit old metatranscriptome data, where taxonomic content may be important but was not analyzed.
Şerban, A.
2016-08-01
The layup optimization of the laminated composites is a very complex topic which involves a convoluted solution space usually explored using heuristic computational techniques. Due to the solution space complexity a lot of layup configurations are evaluated during the optimization process. This fact leads to the mandatory requirement that the configuration evaluation should be fast enough to ensure the convergence of the optimization procedure without sacrificing the accuracy. In this work, we propose a robust, accurate and very fast finite element model based on the first-order shear deformation theory (FSDT). The model is structured in three main parts: preprocessing, processing and post processing. The main strategy is to transfer as much as possible operations in the preprocessing phase which is executed only once and to subsequently reuse the results in the processing and post processing phases which are executed for each layup configuration. Using this strategy, the execution time of the processing and post processing phases is drastically reduced and almost consists of regenerating and solving the global linear system - more that 95%. The proposed procedure is relatively easy to implement in Matlab which holds a very powerful linear system solver for sparse matrices. Also, the accuracy of the model was demonstrated by comparison with Ansys and with some closed form solutions.
Ambikasaran, Sivaram
2015-01-01
Using accurate multi-component diffusion treatment in numerical combustion studies remains formidable due to the computational cost associated with solving for diffusion velocities. To obtain the diffusion velocities, for low density gases, one needs to solve the Stefan-Maxwell equations along with the zero diffusion flux criteria, which scales as $\\mathcal{O}(N^3)$, when solved exactly. In this article, we propose an accurate, fast, direct and robust algorithm to compute multi-component diffusion velocities. To our knowledge, this is the first provably accurate algorithm (the solution can be obtained up to an arbitrary degree of precision) scaling at a computational complexity of $\\mathcal{O}(N)$ in finite precision. The key idea involves leveraging the fact that the matrix of the reciprocal of the binary diffusivities, $V$, is low rank, with its rank being independent of the number of species involved. The low rank representation of matrix $V$ is computed in a fast manner at a computational complexity of $\\...
A fast and robust method to clone and functionally validate T-cell receptors.
Birkholz, Katrin; Hofmann, Christian; Hoyer, Stefanie; Schulz, Birgit; Harrer, Thomas; Kämpgen, Eckhart; Schuler, Gerold; Dörrie, Jan; Schaft, Niels
2009-07-31
Sequencing, cloning and functional testing of T-cell-receptor (TCR) alpha- and beta-chains from T-cell clones is often required in immunotherapy and in immunological research. However, the determination of the TCR chains by a simple PCR is not possible, since, in contrast to the 3' constant domain and untranslated region (UTR), no conserved sequences are present in the 5' region. Furthermore, subsequent functional testing of cloned TCRs requires laborious cell culture experiments, often involving primary human material and time-consuming viral transduction strategies. Here we present a universal PCR-based protocol, adapted from the capswitch technology, that allows for amplification of the TCR alpha- and beta-chain mRNAs without knowledge of the TCR variable domain subtype by attaching a designed sequence to the mRNA's 5' end. Two different MelanA/HLA-A2-specific and one HIVgag/HLA-A2-specific TCR were cloned that way, and were functionally tested by a newly developed easy, fast, and low-cost method: we electroporated Jurkat T cells simultaneously with TCR-encoding RNA and an NFAT-reporter construct, and measured the activation status of the cells upon specific stimulation. The results of this assay correlated with the cytokine release, functional avidity, proliferative activity, and the ability to recognize MelanA/HLA-A2-presenting tumor cells of bulk T cells electroporated with RNA encoding the same TCR. Together these two protocols represent a rapid and low-cost tool for the identification and functional testing of TCRs of T-cell clones, which can then be applied in immunotherapy or immunological research.
Energy Technology Data Exchange (ETDEWEB)
Legou, Th
2002-02-01
This report deals with a fast digital electronic system developed for ion identification and spectroscopy. The system, called IRIS, has been conceived for the super heavy element research program: FUSION. In order to observe a super heavy element, the energy of the compound nucleus implanted in a silicon detector must be measured, and the alpha decay also registered. The associated electronics must therefore handle a very wide range of energies and also exhibit a small recovery time after the implantation of the compound nucleus. IRIS is connected to the output of a charge preamplifier. It digitizes the signal and then executes two digital signal processes: the first to detect the particle, and the second to determine the energy deposited in the silicon detector. The use of programmed processing allows for the adjustment of the digital processing parameters, as well as a choice of other digital signal processing procedures, depending the application. After having explained why a conventional electronic system cannot be used for the detection of super-heavy ions, IRIS' structure is detailed and a number of digital signal processing procedures are studied and tested. (author)
Directory of Open Access Journals (Sweden)
Haryati Jaafar
2015-01-01
Full Text Available Mobile implementation is a current trend in biometric design. This paper proposes a new approach to palm print recognition, in which smart phones are used to capture palm print images at a distance. A touchless system was developed because of public demand for privacy and sanitation. Robust hand tracking, image enhancement, and fast computation processing algorithms are required for effective touchless and mobile-based recognition. In this project, hand tracking and the region of interest (ROI extraction method were discussed. A sliding neighborhood operation with local histogram equalization, followed by a local adaptive thresholding or LHEAT approach, was proposed in the image enhancement stage to manage low-quality palm print images. To accelerate the recognition process, a new classifier, improved fuzzy-based k nearest centroid neighbor (IFkNCN, was implemented. By removing outliers and reducing the amount of training data, this classifier exhibited faster computation. Our experimental results demonstrate that a touchless palm print system using LHEAT and IFkNCN achieves a promising recognition rate of 98.64%.
Enhancing System Realisation in Formal Model Development
DEFF Research Database (Denmark)
Tran-Jørgensen, Peter Würtz Vinther
of formal methods tools into the software development life cycle, and which leverage the formal specification in the subsequent validation of the system. The tools developed use a new code generation infrastructure that has been built as part of this PhD project and implemented in the Overture tool...... of the steps involved in realising the formal specification. This PhD dissertation investigates ways to improve the automation of the steps involved in realising and validating a system based on a formal specification. The approach aims to develop properly designed software tools which support the integration......Software for mission-critical systems is sometimes analysed using formal specification to increase the chances of the system behaving as intended. When sufficient insights into the system have been obtained from the formal analysis, the formal specification is realised in the form of a software...
Baker, Ben; Stachnik, Joshua; Rozhkov, Mikhail
2017-04-01
International Data Center is required to conduct expert technical analysis and special studies to improve event parameters and assist State Parties in identifying the source of specific event according to the protocol to the Protocol to the Comprehensive Nuclear Test Ban Treaty. Determination of seismic event source mechanism and its depth is closely related to these tasks. It is typically done through a strategic linearized inversion of the waveforms for a complete or subset of source parameters, or similarly defined grid search through precomputed Greens Functions created for particular source models. In this presentation we demonstrate preliminary results obtained with the latter approach from an improved software design. In this development we tried to be compliant with different modes of CTBT monitoring regime and cover wide range of source-receiver distances (regional to teleseismic), resolve shallow source depths, provide full moment tensor solution based on body and surface waves recordings, be fast to satisfy both on-demand studies and automatic processing and properly incorporate observed waveforms and any uncertainties a priori as well as accurately estimate posteriori uncertainties. Posterior distributions of moment tensor parameters show narrow peaks where a significant number of reliable surface wave observations are available. For earthquake examples, fault orientation (strike, dip, and rake) posterior distributions also provide results consistent with published catalogues. Inclusion of observations on horizontal components will provide further constraints. In addition, the calculation of teleseismic P wave Green's Functions are improved through prior analysis to determine an appropriate attenuation parameter for each source-receiver path. Implemented HDF5 based Green's Functions pre-packaging allows much greater flexibility in utilizing different software packages and methods for computation. Further additions will have the rapid use of Instaseis
Enhancing System Realisation in Formal Model Development
DEFF Research Database (Denmark)
Tran-Jørgensen, Peter Würtz Vinther
– a formal methods tool that supports the Vienna Development Method. The development of the code generation infrastructure has involved the re-design of the software architecture of Overture. The new architecture brings forth the reuse and extensibility features of Overture to take into account the needs......Software for mission-critical systems is sometimes analysed using formal specification to increase the chances of the system behaving as intended. When sufficient insights into the system have been obtained from the formal analysis, the formal specification is realised in the form of a software...... implementation. One way to realise the system’s software is by automatically generating it from the formal specification – a technique referred to as code generation. However, in general it is difficult to make guarantees about the correctness of the generated code – especially while requiring automation...
DEFF Research Database (Denmark)
Zuidmeer-Jongejan, Laurian; Fernandez-Rivas, Montserrat; Poulsen, Lars K.
2012-01-01
ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqu......ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections...... with aqueous food extracts may be effective but has proven to be accompanied by too many anaphylactic side-effects. FAST aims to develop a safe alternative by replacing food extracts with hypoallergenic recombinant major allergens as the active ingredients of SIT. Both severe fish and peach allergy are caused...... in depth serological and cellular immune analyses will be performed, allowing identification of novel biomarkers for monitoring treatment efficacy. FAST aims at improving the quality of life of food allergic patients by providing a safe and effective treatment that will significantly lower their threshold...
Stable LPV realisation of the Smith predictor
Blanchini, Franco; Casagrande, Daniele; Miani, Stefano; Viaro, Umberto
2016-07-01
The paper is concerned with the control of a linear plant with an output delay. As is known, when the plant parameters do not vary in time, the transfer function approach can be used to find a high-performing controller with the Smith-predictor structure. Such an approach in the domain of the Laplace transform is not directly applicable in the time-variant case. Nevertheless, it is shown that the transfer function of the Smith controller valid for constant values of the parameters can be realised in such a way that closed-loop stability, as well as point-wise optimal performance, is ensured also when the parameters vary with time. The suggested technique is applied to the control of a heat exchanger whose varying parameters include a measurement delay.
Marcacci, Maurilia; Ancora, Massimo; Mangone, Iolanda; Teodori, Liana; Di Sabatino, Daria; De Massis, Fabrizio; Camma', Cesare; Savini, Giovanni; Lorusso, Alessio
2014-06-01
Dynamic surveillance and characterization of canine distemper virus (CDV) circulating strains are essential against possible vaccine breakthroughs events. This study describes the setup of a fast and robust next-generation sequencing (NGS) Ion PGM™ protocol that was used to obtain the complete genome sequence of a CDV isolate (CDV2784/2013). CDV2784/2013 is the prototype of CDV strains responsible for severe clinical distemper in dogs and wolves in Italy during 2013. CDV2784/2013 was isolated on cell culture and total RNA was used for NGS sample preparation. A total of 112.3 Mb of reads were assembled de novo using MIRA version 4.0rc4, which yielded a total number of 403 contigs with 12.1% coverage. The whole genome (15,690 bp) was recovered successfully and compared to those of existing CDV whole genomes. CDV2784/2013 was shown to have 92% nt identity with the Onderstepoort vaccine strain. This study describes for the first time a fast and robust Ion PGM™ platform-based whole genome amplification protocol for non-segmented negative stranded RNA viruses starting from total cell-purified RNA. Additionally, this is the first study reporting the whole genome analysis of an Arctic lineage strain that is known to circulate widely in Europe, Asia and USA.
Anisimova, Maria; Gil, Manuel; Dufayard, Jean-François; Dessimoz, Christophe; Gascuel, Olivier
2011-01-01
Phylogenetic inference and evaluating support for inferred relationships is at the core of many studies testing evolutionary hypotheses. Despite the popularity of nonparametric bootstrap frequencies and Bayesian posterior probabilities, the interpretation of these measures of tree branch support remains a source of discussion. Furthermore, both methods are computationally expensive and become prohibitive for large data sets. Recent fast approximate likelihood-based measures of branch supports (approximate likelihood ratio test [aLRT] and Shimodaira–Hasegawa [SH]-aLRT) provide a compelling alternative to these slower conventional methods, offering not only speed advantages but also excellent levels of accuracy and power. Here we propose an additional method: a Bayesian-like transformation of aLRT (aBayes). Considering both probabilistic and frequentist frameworks, we compare the performance of the three fast likelihood-based methods with the standard bootstrap (SBS), the Bayesian approach, and the recently introduced rapid bootstrap. Our simulations and real data analyses show that with moderate model violations, all tests are sufficiently accurate, but aLRT and aBayes offer the highest statistical power and are very fast. With severe model violations aLRT, aBayes and Bayesian posteriors can produce elevated false-positive rates. With data sets for which such violation can be detected, we recommend using SH-aLRT, the nonparametric version of aLRT based on a procedure similar to the Shimodaira–Hasegawa tree selection. In general, the SBS seems to be excessively conservative and is much slower than our approximate likelihood-based methods. PMID:21540409
Benoit, Commercon; Romain, Teyssier
2014-01-01
Implicit solvers present strong limitations when used on supercomputing facilities and in particular for adaptive mesh-refinement codes. We present a new method for implicit adaptive time-stepping on adaptive mesh refinement-grids and implementing it in the radiation hydrodynamics solver we designed for the RAMSES code for astrophysical purposes and, more particularly, for protostellar collapse. We briefly recall the radiation hydrodynamics equations and the adaptive time-stepping methodology used for hydrodynamical solvers. We then introduce the different types of boundary conditions (Dirichlet, Neumann, and Robin) that are used at the interface between levels and present our implementation of the new method in the RAMSES code. The method is tested against classical diffusion and radiation hydrodynamics tests, after which we present an application for protostellar collapse. We show that using Dirichlet boundary conditions at level interfaces is a good compromise between robustness and accuracy and that it ca...
Dalimier, E.; Oks, E.
2017-01-01
Transport phenomena in plasmas, such as, e.g., resistivity, can be affected by electrostatic turbulence that frequently occurs in various kinds of laboratory and astrophysical plasmas. Transport phenomena are affected most significantly by a low-frequency electrostatic turbulence—such as, e.g., ion acoustic waves, also known as ionic sound—causing anomalous resistivity. In this case, for computing profiles of spectral lines, emitted by plasma ions, by any appropriate code for diagnostic purposes, it is necessary to calculate the distribution of the total quasistatic field. For a practically important situation, where the average turbulent field is much greater than the characteristic ion microfield, we develop a robust computational method valid for any appropriate distribution of the ion microfield at a charged point. We show that the correction to the Rayleigh distribution of the turbulent field is controlled by the behavior of the ion microfield distribution at large fields—in distinction to the opposite (and therefore, erroneous) result in the literature. We also obtain a universal analytical expression for the correction to the Rayleigh distribution based on the asymptotic of the ion microfield distribution at large fields at a charged point. By comparison with various known distributions of the ion microfield, we show that our asymptotic formula has a sufficiently high accuracy. Also exact computations are used to verify the high accuracy of the method. This robust approximate, but accurate method yields faster computational results than the exact calculations and therefore should be important for practical situations requiring simultaneous computations of a large number of spectral lineshapes (e.g., for calculating opacities)—especially for laser-produced plasmas.
A feasible central limit theory for realised volatility under leverage
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Shephard, Neil
In this note we show that the feasible central limit theory for realised volatility and realised covariation recently developed by Barndor-Nielsen and Shephard applies under arbitrary diusion based leverage eects. Results from a simulation experiment suggest that the feasible version of the limit...
Wen, Zhuoman; Wang, Yanjie; Luo, Jun; Kuijper, Arjan; Di, Nan; Jin, Minghe
2017-07-01
When a space robotic arm deploys a payload, usually the pose between the cooperative target fixed on the payload and the hand-eye camera installed on the arm is calculated in real-time. A high-precision robust visual cooperative target localization method is proposed. Combing a circle, a line and dots as markers, a target that guarantees high detection rates is designed. Given an image, single-pixel-width smooth edges are drawn by a novel linking method. Circles are then quickly extracted using isophotes curvature. Around each circle, a square boundary in a pre-calculated proportion to the circle radius is set. In the boundary, the target is identified if certain numbers of lines exist. Based on the circle, the lines, and the target foreground and background intensities, markers are localized. Finally, the target pose is calculated by the Point-3-Perspective algorithm. The algorithm processes 8 frames per second with the target distance ranging from 0.3m to 1.5 m. It generated high-precision poses of above 97.5% on over 100,000 images regardless of camera background, target pose, illumination and motion blur. At 0.3 m, the rotation and translation errors were less than 0.015° and 0.2 mm. The proposed algorithm is very suitable for real-time visual measurement that requires high precision in aerospace.
Yuan, Wu; Kut, Carmen; Liang, Wenxuan; Li, Xingde
2017-03-01
Cancer is known to alter the local optical properties of tissues. The detection of OCT-based optical attenuation provides a quantitative method to efficiently differentiate cancer from non-cancer tissues. In particular, the intraoperative use of quantitative OCT is able to provide a direct visual guidance in real time for accurate identification of cancer tissues, especially these without any obvious structural layers, such as brain cancer. However, current methods are suboptimal in providing high-speed and accurate OCT attenuation mapping for intraoperative brain cancer detection. In this paper, we report a novel frequency-domain (FD) algorithm to enable robust and fast characterization of optical attenuation as derived from OCT intensity images. The performance of this FD algorithm was compared with traditional fitting methods by analyzing datasets containing images from freshly resected human brain cancer and from a silica phantom acquired by a 1310 nm swept-source OCT (SS-OCT) system. With graphics processing unit (GPU)-based CUDA C/C++ implementation, this new attenuation mapping algorithm can offer robust and accurate quantitative interpretation of OCT images in real time during brain surgery.
Cover, Keith S
2008-01-01
While the multiexponential nature of T2 decays measured in vivo is well known, characterizing T2 decays by a single time constant is still very useful when differentiating among structures and pathologies in MRI images. A novel, robust, fast and very simple method is presented for both estimating and displaying the average time constant for the T2 decay of each pixel from a multiecho MRI sequence. The average time constant is calculated from the average of the values measured from the T2 decay over many echoes. For a monoexponential decay, the normalized decay average varies monotonically with the time constant. Therefore, it is simple to map any normalized decay average to an average time constant. This method takes advantage of the robustness of the normalized decay average to both artifacts and multiexponential decays. Color intensity projections (CIPs) were used to display 32 echoes acquired at a 10ms spacing as a single color image. The brightness of each pixel in each color image was determined by the i...
Yuan, Wu; Kut, Carmen; Liang, Wenxuan; Li, Xingde
2017-01-01
Cancer is known to alter the local optical properties of tissues. The detection of OCT-based optical attenuation provides a quantitative method to efficiently differentiate cancer from non-cancer tissues. In particular, the intraoperative use of quantitative OCT is able to provide a direct visual guidance in real time for accurate identification of cancer tissues, especially these without any obvious structural layers, such as brain cancer. However, current methods are suboptimal in providing high-speed and accurate OCT attenuation mapping for intraoperative brain cancer detection. In this paper, we report a novel frequency-domain (FD) algorithm to enable robust and fast characterization of optical attenuation as derived from OCT intensity images. The performance of this FD algorithm was compared with traditional fitting methods by analyzing datasets containing images from freshly resected human brain cancer and from a silica phantom acquired by a 1310 nm swept-source OCT (SS-OCT) system. With graphics processing unit (GPU)-based CUDA C/C++ implementation, this new attenuation mapping algorithm can offer robust and accurate quantitative interpretation of OCT images in real time during brain surgery. PMID:28327613
Vajuvalli, Nithin N.; Chikkemenahally, Dharmendra Kumar K.; Nayak, Krupa N.; Bhosale, Manoj G.; Geethanath, Sairam
2016-12-01
Dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) is a well-established method for non-invasive detection and therapeutic monitoring of pathologies through administration of intravenous contrast agent. Quantification of pharmacokinetic (PK) maps can be achieved through application of compartmental models relevant to the pathophysiology of the tissue under interrogation. The determination of PK parameters involves fitting of time-concentration data to these models. In this work, the Tofts model in frequency domain (TM-FD) is applied to a weakly vascularized tissue such as the breast. It is derived as a convolution-free model from the conventional Tofts model in the time domain (TM-TD). This reduces the dimensionality of the curve-fitting problem from two to one. The approaches of TM-FD and TM-TD were applied to two kinds of in silico phantoms and six in vivo breast DCE data sets with and without the addition of noise. The results showed that computational time taken to estimate PK maps using TM-FD was 16-25% less than with TM-TD. Normalized root mean square error (NRMSE) calculation and Pearson correlation analyses were performed to validate robustness and accuracy of the TM-FD and TM-TD approaches. These compared with ground truth values in the case of phantom studies for four different temporal resolutions. Results showed that NRMSE values for TM-FD were significantly lower than those of TM-TD as validated by a paired t-test along with reduced computational time. This approach therefore enables online evaluation of PK maps by radiologists in a clinical setting, aiding in the evaluation of 3D and/or increased coverage of the tissue of interest.
Timofey, Sizonenko; Karsanina, Marina; Byuk, Irina; Gerke, Kirill
2016-04-01
To characterize pore structure relevant to single and multi-phase flow modelling it is of special interest to extract topology of the pore space. This is usually achieved using so-called pore-network models. Such models are useful not only to characterize pore space and pore size distributions, but also provide means to simulate flow and transport with very limited computational resources compared to other pore-scale modelling techniques. The main drawback of the pore-network approach is that they have first to simplify the pore space geometry. This crucial step is both time consuming and prone to numerous errors. Two most popular methods based on median axis or inscribed maximal balls have their own strong sides and disadvantages. To address aforementioned problems related to pore-network extraction here we propose a novel method utilizing the advantages of both popular approaches. Combining two algorithms resulted in much faster and robust extraction methodology. Moreover, we have found that accurate topology representation requires extension of the conventional pore-body and pore-throat classification. We test our new methodology using pore structures with "analytical solutions" such as different sphere packs. In addition, we rigorously compare it against inscribed maximal balls methodology's results using numerous 3D images of sandstone and carbonate rocks, soils and some other porous materials. Another verification includes permeability calculations which are also compared both against lab data and voxel based pore-scale modelling simulations. This work was partially supported by RFBR grant 15-34-20989 (X-ray tomography and image fusion) and RSF grant 14-17-00658 (image segmentation and pore-scale modelling).
Robust X-band LNAs in AlGaN/GaN technology
Janssen, J.P.B.; Heijningen, M. van; Visser, G.C.; Rodenburg, M.; Johnson, H.K.; Uren, M.J.; Morvan, E.; Vliet, F.E. van
2009-01-01
Gallium-Nitride technology is known for its high power density and power amplifier designs, but is also very well suited to realise robust receiver components. This paper presents the design, realisation and measurement of two robust AlGaN/GaN low noise amplifiers. The two versions have been designe
Tone realisation in a Yoruba speech recognition corpus
CSIR Research Space (South Africa)
Van Niekerk, D
2012-05-01
Full Text Available The authors investigate the acoustic realisation of tone in short continuous utterances in Yoruba. Fundamental frequency contours are extracted for automatically aligned syllables from a speech corpus of 33 speakers collected for speech recognition...
Directory of Open Access Journals (Sweden)
Cihan Ulas
2013-11-01
Full Text Available Simultaneous localization and mapping (SLAM plays an important role in fully autonomous systems when a GNSS (global navigation satellite system is not available. Studies in both 2D indoor and 3D outdoor SLAM are based on the appearance of environments and utilize scan-matching methods to find rigid body transformation parameters between two consecutive scans. In this study, a fast and robust scan-matching method based on feature extraction is introduced. Since the method is based on the matching of certain geometric structures, like plane segments, the outliers and noise in the point cloud are considerably eliminated. Therefore, the proposed scan-matching algorithm is more robust than conventional methods. Besides, the registration time and the number of iterations are significantly reduced, since the number of matching points is efficiently decreased. As a scan-matching framework, an improved version of the normal distribution transform (NDT is used. The probability density functions (PDFs of the reference scan are generated as in the traditional NDT, and the feature extraction - based on stochastic plane detection - is applied to the only input scan. By using experimental dataset belongs to an outdoor environment like a university campus, we obtained satisfactory performance results. Moreover, the feature extraction part of the algorithm is considered as a special sampling strategy for scan-matching and compared to other sampling strategies, such as random sampling and grid-based sampling, the latter of which is first used in the NDT. Thus, this study also shows the effect of the subsampling on the performance of the NDT.
Optimal realisations of two-dimensional, totally-decomposable metrics
Herrmann, Sven; Lesser, Alice; Moulton, Vincent; Wu, Taoyang
2011-01-01
A realisation of a metric d on a finite set X is a weighted graph (G,w) whose vertex set contains X such that the shortest-path distance between elements of X considered as vertices in G is equal to d. Such a realisation (G,w) is called optimal if the sum of its edge weights is minimal over all such realisations. Optimal realisations always exist, although it is NP-hard to compute them in general, and they have applications in areas such as phylogenetics, electrical networks and internet tomography. In [Adv. in Math. 53, 1984, 321-402] A. Dress showed that the optimal realisations of a metric d are closely related to a certain polytopal complex that can be canonically associated to d called its tight-span. Moreover, he conjectured that the (weighted) graph consisting of the zero- and one-dimensional faces of the tight-span of d must always contain an optimal realisation as a homeomorphic subgraph. In this paper, we prove that this conjecture does indeed hold for a certain class of metrics, namely the class of...
Lochy, Aliette; Van Belle, Goedele; Rossion, Bruno
2015-01-01
Despite decades of research on reading, including the relatively recent contributions of neuroimaging and electrophysiology, identifying selective representations of whole visual words (in contrast to pseudowords) in the human brain remains challenging, in particular without an explicit linguistic task. Here we measured discrimination responses to written words by means of electroencephalography (EEG) during fast periodic visual stimulation. Sequences of pseudofonts, nonwords, or pseudowords were presented through sinusoidal contrast modulation at a periodic 10 Hz frequency rate (F), in which words were interspersed at regular intervals of every fifth item (i.e., F/5, 2 Hz). Participants monitored a central cross color change and had no linguistic task to perform. Within only 3 min of stimulation, a robust discrimination response for words at 2 Hz (and its harmonics, i.e., 4 and 6 Hz) was observed in all conditions, located predominantly over the left occipito-temporal cortex. The magnitude of the response was largest for words embedded in pseudofonts, and larger in nonwords than in pseudowords, showing that list context effects classically reported in behavioral lexical decision tasks are due to visual discrimination rather than decisional processes. Remarkably, the oddball response was significant even for the critical words/pseudowords discrimination condition in every individual participant. A second experiment replicated this words/pseudowords discrimination, and showed that this effect is not accounted for by a higher bigram frequency of words than pseudowords. Without any explicit task, our results highlight the potential of an EEG fast periodic visual stimulation approach for understanding the representation of written language. Its development in the scientific community might be valuable to rapidly and objectively measure sensitivity to word processing in different human populations, including neuropsychological patients with dyslexia and other reading
Realising the Uncertainty Enabled Model Web
Cornford, D.; Bastin, L.; Pebesma, E. J.; Williams, M.; Stasch, C.; Jones, R.; Gerharz, L.
2012-12-01
The FP7 funded UncertWeb project aims to create the "uncertainty enabled model web". The central concept here is that geospatial models and data resources are exposed via standard web service interfaces, such as the Open Geospatial Consortium (OGC) suite of encodings and interface standards, allowing the creation of complex workflows combining both data and models. The focus of UncertWeb is on the issue of managing uncertainty in such workflows, and providing the standards, architecture, tools and software support necessary to realise the "uncertainty enabled model web". In this paper we summarise the developments in the first two years of UncertWeb, illustrating several key points with examples taken from the use case requirements that motivate the project. Firstly we address the issue of encoding specifications. We explain the usage of UncertML 2.0, a flexible encoding for representing uncertainty based on a probabilistic approach. This is designed to be used within existing standards such as Observations and Measurements (O&M) and data quality elements of ISO19115 / 19139 (geographic information metadata and encoding specifications) as well as more broadly outside the OGC domain. We show profiles of O&M that have been developed within UncertWeb and how UncertML 2.0 is used within these. We also show encodings based on NetCDF and discuss possible future directions for encodings in JSON. We then discuss the issues of workflow construction, considering discovery of resources (both data and models). We discuss why a brokering approach to service composition is necessary in a world where the web service interfaces remain relatively heterogeneous, including many non-OGC approaches, in particular the more mainstream SOAP and WSDL approaches. We discuss the trade-offs between delegating uncertainty management functions to the service interfaces themselves and integrating the functions in the workflow management system. We describe two utility services to address
Yuan, Long; Luo, Yi; Kandoussi, Hamza; Ji, Qin C
2016-12-01
Serum 7α-hydroxy-cholesten-3-one (C4) has been reported as a biomarker to assess CYP7A1 enzyme activity and bile acid synthesis. To support a clinical program, a sensitive and reliable assay without derivatization was required for the analysis of C4 in human serum. Methodology & results: A systematic approach was used to optimize mass spectrometry, LC and sample extraction conditions, therefore, significantly improved assay sensitivity, and achieved the required quantification limit without derivatization. A surrogate matrix approach was used to overcome the interference from endogenous C4. A stable isotope-labeled C4 was used as internal standard. The samples were extracted using a simple protein precipitation method with 2% formic acid in acetonitrile. A simple, fast, sensitive and robust UHPLC-MS/MS method for the quantification of 0.50 ng/ml C4 in 100 µl human serum was developed and fit for purpose validated. The method was successfully applied to the bioanalysis of C4 in a clinical study.
Seidel, A.; Wagner, S.; Dreizler, A.; Ebert, V.
2015-05-01
We have developed a fast, spatially scanning direct tunable diode laser absorption spectrometer (dTDLAS) that combines four polygon-mirror based scanning units with low-cost retro-reflective foils. With this instrument, tomographic measurements of absolute 2-D water vapor concentration profiles are possible without any calibration using a reference gas. A spatial area of 0.8 m x 0.8 m was covered, which allows for application in soil physics, where greenhouse gas emission from certain soil structures shall be monitored. The whole concentration field was measured with up to 2.5 Hz. In this paper, we present the setup and spectroscopic performance of the instrument regarding the influence of the polygon rotation speed and mode on the absorption signal. Homogeneous H2O distributions were measured and compared to a single channel, bi-static reference TDLAS spectrometer for validation of the instrument. Good accuracy and precision with errors of less than 6% of the absolute concentration and length and bandwidth normalized detection limits of up to 1.1 ppmv . m (Hz)-0.5 were achieved. The spectrometer is a robust and easy to set up instrument for tomographic reconstructions of 2-D-concentration fields that can be considered as a good basis for future field measurements in environmental research.
Seidel, A.; Wagner, S.; Dreizler, A.; Ebert, V.
2014-12-01
We have developed a fast, spatially direct scanning tunable diode laser absorption spectrometer (dTDLAS) that combines four polygon-mirror based scanning units with low-cost retro-reflective foils. With this instrument, tomographic measurements of absolute 2-D water vapour concentration profiles are possible without any calibration using a reference gas. A spatial area of 0.8 m × 0.8 m was covered, which allows for application in soil physics, where greenhouse gas emission from certain soil structures shall be monitored. The whole concentration field was measured with up to 2.5 Hz. In this paper, we present the setup and spectroscopic performance of the instrument regarding the influence of the polygon rotation speed and mode on the absorption signal. Homogeneous H2O distributions were measured and compared to a single channel, bi-static reference TDLAS spectrometer for validation of the instrument. Good accuracy and precision with errors of less than 6% of the absolute concentration and length and bandwidth normalized detection limits of up to 1.1 ppmv · m · √Hz-1 were achieved. The spectrometer is a robust and easy to set up instrument for tomographic reconstructions of 2-D-concentration fields that can be considered a good basis for future field measurements in environmental research.
Risser, Laurent; Vincent, Thomas; Ciuciu, Philippe; Idier, Jérôme
2009-01-01
In this paper, we present a fast numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon a classical path-sampling method to approximate a small subset of reference PFs corresponding to prespecified regions. Then, the proposed extrapolation method allows us to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible.
Disseminating the unit of mass from multiple primary realisations
Nielsen, Lars
2016-12-01
When a new definition of the kilogram has been adopted in 2018 as expected, the unit of mass will be realised by the watt balance method, the x-ray crystal density method or perhaps other primary methods still to be developed. So far, the standard uncertainties associated with the available primary methods are at least one order of magnitude larger than the standard uncertainty associated with mass comparisons using mass comparators, so differences in primary realisations of the kilogram are easily detected, whereas many National Metrology Institutes would have to increase their calibration and measurement capabilities (CMCs) if they were traceable to a single primary realisation. This paper presents a scheme for obtaining traceability to multiple primary realisations of the kilogram using a small group of stainless steel 1 kg weights, which are allowed to change their masses over time in a way known to be realistic, and which are calibrated and stored in air. An analysis of the scheme shows that if the relative standard uncertainties of future primary realisations are equal to the relative standard uncertainties of the present methods used to measure the Planck constant, the unit of mass can be disseminated with a standard uncertainty less than 0.015 mg, which matches the smallest CMCs currently claimed for the calibration of 1 kg weights.
Detector Based Realisation of Illuminance Scale at NML-SIRIM
Abdullah, Mohd Nizam; Abidin, Mohd Nasir Zainal; Abidin, Abdul Rashid Zainal; Shaari, Sahbudin
2009-07-01
Illuminance scale is one of the fundamentals in the realisation of candela in optical radiation. The en route of the realisation is based on the fundamental process from the unbroken chain of traceability which includes from the primary standard disseminated to working standard and lastly the end user. There are many variations towards this realisation even though some of the national metrology institutes (NMI) does not have the primary standard but their traceability still valid. The realisation of National Metrology Laboratory SIRIM (NML-SIRIM), Malaysia illuminance scale is based on detector. The scale is traceable to National Physical Labortaory (NPL), United Kingdom (UK) by annually calibrating photometers and luminous intensity lamp. This paper describes measurement method and the system set-up was previously crosschecked with Korea Research Institute Standards and Science (KRISS), Republic of Korea. The agreement between both laboratories is within 0.5% the uncertainty maintained at NML-SIRIM. Furthermore, the basic measurement equation for illuminance realisation is also derived.
Energy Technology Data Exchange (ETDEWEB)
Jensen, O.M.
2004-07-01
Many years' efforts within the energy labelling area have shown large saving potentials in heating and use of electricity in buildings. At the same time it has been proved that these saving potentials, even when economically advantageous, only are cashed to a limited extent. The reason to this is ascribed to barriers that meet the individual building owner who wants to start saving energy. Most barriers are known and a lot of these have been sought overcome for some time. The questions are how many barriers still exist, have new barriers arisen and the character of these barriers. On this background the objective of this survey has been to concretize and study the barriers, which are blocking reasonable energy savings. Focus has especially been on barriers for realisation of heating savings, but through a general evaluation of energy savings of barriers other forms of energy saving methods have been taken into consideration. Special interest has been directed towards houses, typically one family houses, which are affected by the Energy Labelling Scheme. The concept barriers include all kinds of barriers, also barriers that not are acknowledged as barriers by the individual house owner, or that on closer inspection turn out to be something else than actual barriers. This note suggests an alternative inertia model, in order to create an idea of the inertness characteristic of the many house owners who understand the message but fail to act on it. (BA)
Chavez, Gustavo Ivan
2017-07-10
This dissertation introduces a novel fast direct solver and preconditioner for the solution of block tridiagonal linear systems that arise from the discretization of elliptic partial differential equations on a Cartesian product mesh, such as the variable-coefficient Poisson equation, the convection-diffusion equation, and the wave Helmholtz equation in heterogeneous media. The algorithm extends the traditional cyclic reduction method with hierarchical matrix techniques. The resulting method exposes substantial concurrency, and its arithmetic operations and memory consumption grow only log-linearly with problem size, assuming bounded rank of off-diagonal matrix blocks, even for problems with arbitrary coefficient structure. The method can be used as a standalone direct solver with tunable accuracy, or as a black-box preconditioner in conjunction with Krylov methods. The challenges that distinguish this work from other thrusts in this active field are the hybrid distributed-shared parallelism that can demonstrate the algorithm at large-scale, full three-dimensionality, and the three stressors of the current state-of-the-art multigrid technology: high wavenumber Helmholtz (indefiniteness), high Reynolds convection (nonsymmetry), and high contrast diffusion (inhomogeneity). Numerical experiments corroborate the robustness, accuracy, and complexity claims and provide a baseline of the performance and memory footprint by comparisons with competing approaches such as the multigrid solver hypre, and the STRUMPACK implementation of the multifrontal factorization with hierarchically semi-separable matrices. The companion implementation can utilize many thousands of cores of Shaheen, KAUST\\'s Haswell-based Cray XC-40 supercomputer, and compares favorably with other implementations of hierarchical solvers in terms of time-to-solution and memory consumption.
Realisation of a Frequency Standard Using an Atomic Fountain
Michaud, A; Zetie, K P; Cooper, C J; Hillenbrand, G; Lorent, V; Steane, A; Foot, C J
2005-01-01
We report the realisation and preliminary study of a frequency standard using a fountain of laser cooled caesium atoms. Our apparatus uses a magneto-optical trap as a source of cold atoms and optical pumping to prepare the atoms in the correct state before they enter the microwave cavity.
Systematic realisation of control flow analyses for CML
DEFF Research Database (Denmark)
Gasser, K.L.S.; Nielson, Flemming; Nielson, Hanne Riis
1997-01-01
for terminating w well as non-terminating programs. The analysis is defined coinductively and it is shown that all programs have a least analysis result (that is indeed the best one). To realise the analysis we massage the specification in three stages: (i) to explicitly record reachability of subexpressions, (ii...
Design and realisation of a quasi monolithic silicon load cell
Wensink, H.; Wiegerink, R.J.; Zwijze, A.F.; Boer, de M.J.; Elwenspoek, M.C.
1998-01-01
In this paper, the first silicon load cell is presented designed for measuring a load up to 1000 kg. A prototype has been realised. An improved cryogenic RIE process with high aspect ratio was developed for the fabrication of thin springs. Low temperature silicon direct bonding was used for the fina
Energy Technology Data Exchange (ETDEWEB)
Simeonova-Chergou, Anna; Jahnke, Anika; Siebenlist, Kerstin; Stieler, Florian; Mai, Sabine; Boda-Heggemann, Judit; Wenz, Frederik; Lohr, Frank; Jahnke, Lennart [University Medical Center Mannheim, University of Heidelberg, Department of Radiotherapy and Oncology, Mannheim (Germany)
2016-03-15
High-dose radiotherapy of lung cancer is challenging. Tumors may move by up to 2 cm in craniocaudal and anteroposterior directions as a function of breathing cycle. Tumor displacement increases with treatment time, which consequentially increases the treatment uncertainty. This study analyzed whether automatically gated cone-beam-CT (CBCT)-controlled intensity modulated fast deep inspiration breath hold (DIBH) stereotactic body radiation therapy (SBRT) in flattening filter free (FFF) technique and normofractionated lung DIBH intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) treatments delivered with a flattening filter can be applied with sufficient accuracy within a clinically acceptable timeslot. Plans of 34 patients with lung tumors were analyzed. Of these patients, 17 received computer-controlled fast DIBH SBRT with a dose of 60 Gy (5 fractions of 12 Gy or 12 fractions of 5 Gy) in an FFF VMAT technique (FFF-SBRT) every other day and 17 received conventional VMAT with a flattening filter (conv-VMAT) and 2-Gy daily fractional doses (cumulative dose 50-70 Gy). FFF-SBRT plans required more monitor units (MU) than conv-VMAT plans (2956.6 ± 885.3 MU for 12 Gy/fraction and 1148.7 ± 289.2 MU for 5 Gy/fraction vs. 608.4 ± 157.5 MU for 2 Gy/fraction). Total treatment and net beam-on times were shorter for FFF-SBRT plans than conv-VMAT plans (268.0 ± 74.4 s vs. 330.2 ± 93.6 s and 85.8 ± 25.3 s vs. 117.2 ± 29.6 s, respectively). Total slot time was 13.0 min for FFF-SBRT and 14.0 min for conv-VMAT. All modalities could be delivered accurately despite multiple beam-on/-off cycles and were robust against multiple interruptions. Automatically gated CBCT-controlled fast DIBH SBRT in VMAT FFF technique and normofractionated lung DIBH VMAT can be applied with a low number of breath-holds in a short timeslot, with excellent dosimetric accuracy. In clinical routine, these approaches combine optimally reduced lung tissue irradiation with maximal
Manipulation of entanglement and its realisation using trapped ions
Jonathan, D
2001-01-01
Entanglement is a fundamental physical resource at the heart of quantum information theory. This Thesis contributes to its study by approaching it from two separate directions: the laws governing its manipulation, and its creation within a concrete physical setting. I begin by studying the manipulation of entangled pure states of two quantum systems when (i) only a single copy of each system is available and (ii) only a restricted class of physical operations are allowed to be performed on them. One physically reasonable class, denoted LQCC, is the set of all possible quantum operations realised on each system by local agents, who are allowed to communicate with each other only by classical means. Given these conditions, I find a minimal set of entropic-like state functions that completely determine which manipulations can be realised. Applications to useful protocols such as entanglement concentration are discussed. Further elaboration allows also the determination of the most faithful approximation to a giv...
Looking for the minimal realisation of the inverse seesaw
Abada, Asmaa
2014-01-01
In this work we consider a simple extension of the Standard Model involving additional fermionic singlets and assume an underlying inverse seesaw mechanism for neutrino mass~generation. Our goal is to determine which is the minimal realisation that accounts for neutrino data while at the same time complying with all experimental requirements (electroweak precision tests and laboratory constraints). This study aims at identifying the minimal inverse seesaw realisation for the 3-flavour and for the 3 + more-mixing schemes, the latter giving an explanation for the reactor anomalies and/or providing a possible candidate for the dark matter of the Universe. Based on a perturbative approach, our generic study shows that in the class of models giving rise to a 3-flavour flavour mixing scheme, only two mass scales are relevant (the light neutrino mass scale, $m_\
Investigating benefits realisation process for enterprise resource planning systems
Badewi, Amgad
2016-01-01
This research aims to investigate the benefit realisation process for ERP systems so as to develop a benefit realization road map whereby organisations can realize the maximum potential of their ERP systems. This research covers two areas: mechanism of implementation and the destination to change (i.e. road map). It has been found that project management and benefits management approaches are necessary for recouping benefits from investing in Information Technologies (IT) pr...
Robust procedures in chemometrics
DEFF Research Database (Denmark)
Kotwa, Ewelina
-way chemometrical methods, such as PCA and PARAFAC models for analysing spatial and depth profiles of sea water samples, defined by three data modes: depth, variables and geographical location. Emphasis was also put on predicting fluorescence values, as being a natural measure of biological activity, by applying....... applying a multivariate and multi-way data analytical frame-work in fields where less sophisticated data analysis methods are currently used, and 2. developing new, more robust alternatives to already existing multivariate tools. The first part of the study was realised by applying two- and three...... and comparing the Partial Least Squares (PLS) regression technique with its multi-way alternative, N-PLS. Results of the analysis indicated superiority of the three-way frame-work, potentially constituting a novel assessment of the sea water measurements. Particularly in the case of regression models...
Fernandez, R.; Abderrahim, H. Aït; Baeten, P.; de Bruyn, D.; Maes, D.; Mazouzi, A. Al; Ariën, B.; Malambu, E.; Schuurmans, P.; Schyns, M.; Sobolev, V.; van den Eynde, G.; Vandeplassche, D.
2010-06-01
The coupling between an accelerator, a spallation target and a subcritical core has been studied for the first time at SCK•CEN in collaboration with Ion Beam Applications (IBA, Louvain-la-Neuve) in the frame of the ADONIS project (1995-1997). ADONIS was a small irradiation facility, based on the ADS concept, having a dedicated objective to produce radioisotopes for medical purposes and more particularly 99Mo as a fission product from highly enriched 235U (HEU) fissile targets. The ad-hoc scientific advisory committee recommended extending the purpose of the ADONIS machine to become a Material Testing Reactor (MTR) for material and fuel research, to study the feasibility of transmutation of the minor actinides and to demonstrate at a reasonable power scale the principle of the ADS. The project, since 1998 named MYRRHA, has then evolved to a larger installation. MYRRHA is now conceived as a flexible irradiation facility, able to work as an Accelerator Driven (subcritical mode) and in critical mode. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV systems, material developments for fusion reactors, radioisotope production for medical and industrial applications and industrial applications, such as Si-doping. MYRRHA will also demonstrate the ADS full concept by coupling the three components (accelerator, spallation target and subcritical reactor) at reasonable power level to allow operation feedback, scalable to an industrial demonstrator and allow the study of efficient transmutation of high-level nuclear waste. Since MYRRHA is based on the heavy liquid metal technology, the eutectic lead-bismuth, it will be able to significantly contribute to the development of Lead Fast Reactor Technology. Since MYRRHA will also be operated in critical mode, MYRRHA can even better play the role of European Technology Pilot Plant in the roadmap for LFR.
Realisation of a Lorentz algebra in Lorentz violating theory
Energy Technology Data Exchange (ETDEWEB)
Ganguly, Oindrila [S. N. Bose National Centre for Basic Sciences, Kolkata (India)
2012-11-15
A Lorentz non-invariant higher derivative effective action in flat spacetime, characterised by a constant vector, can be made invariant under infinitesimal Lorentz transformations by restricting the allowed field configurations. These restricted fields are defined as functions of the background vector in such a way that background dependence of the dynamics of the physical system is no longer manifest. We show here that they also provide a field basis for the realisation of a Lorentz algebra and allow the construction of a Poincare invariant symplectic two-form on the covariant phase space of the theory. (orig.)
Kormány, Róbert; Fekete, Jenő; Guillarme, Davy; Fekete, Szabolcs
2014-02-01
The goal of this study was to evaluate the accuracy of simulated robustness testing using commercial modelling software (DryLab) and state-of-the-art stationary phases. For this purpose, a mixture of amlodipine and its seven related impurities was analyzed on short narrow bore columns (50×2.1mm, packed with sub-2μm particles) providing short analysis times. The performance of commercial modelling software for robustness testing was systematically compared to experimental measurements and DoE based predictions. We have demonstrated that the reliability of predictions was good, since the predicted retention times and resolutions were in good agreement with the experimental ones at the edges of the design space. In average, the retention time relative errors were software, we proved that the separation was feasible on all columns within the same analysis time (less than 4min), by proper adjustments of variables. Copyright © 2013 Elsevier B.V. All rights reserved.
Design, Testing, and Realisation of a Medium Size Aerostat Envelope
Directory of Open Access Journals (Sweden)
A. Kumar
2016-03-01
Full Text Available The design, testing and realisation aspects during the development of a medium size aerostat envelope in the present work. The payload capacity of this aerostat is 300 kg at 1 km above mean sea level. The aerostat envelope is the aerodynamically shaped fabric enclosure part of the aerostat which generally uses helium for lifting useful payloads to a specified height. The envelope volume estimation technique is discussed which provides the basis for sizing. The design, material selection, testing and realisation aspects of this aerostat envelope are also discussed. The empirical formulas and finite element analysis are used to estimate the aerodynamic, structural and other design related parameters of the aerostat. Equilibrium studies are then explained for balancing forces and moments in static conditions. The tether profile estimation technique is discussed to estimate blow by distance and tether length. A comparison of estimated and measured performance parameters during trials has also been discussed.Defence Science Journal, Vol. 66, No. 2, March 2016, pp.93-99, DOI: http://dx.doi.org/10.14429/dsj.66.9291
Brouard, Olivier; Delannay, Fabrice; Ricordel, Vincent; Barba, Dominique
2007-01-01
4 pages; International audience; Motion segmentation methods are effective for tracking video objects. However, objects segmentation methods based on motion need to know the global motion of the video in order to back-compensate it before computing the segmentation. In this paper, we propose a method which estimates the global motion of a High Definition (HD) video shot and then segments it using the remaining motion information. First, we develop a fast method for multi-resolution motion est...
Trinh, Hung-Cuong; Le, Duc-Hau; Kwon, Yung-Keun
2014-01-01
It has been a challenge in systems biology to unravel relationships between structural properties and dynamic behaviors of biological networks. A Cytoscape plugin named NetDS was recently proposed to analyze the robustness-related dynamics and feed-forward/feedback loop structures of biological networks. Despite such a useful function, limitations on the network size that can be analyzed exist due to high computational costs. In addition, the plugin cannot verify an intrinsic property which can be induced by an observed result because it has no function to simulate the observation on a large number of random networks. To overcome these limitations, we have developed a novel software tool, PANET. First, the time-consuming parts of NetDS were redesigned to be processed in parallel using the OpenCL library. This approach utilizes the full computing power of multi-core central processing units and graphics processing units. Eventually, this made it possible to investigate a large-scale network such as a human signaling network with 1,609 nodes and 5,063 links. We also developed a new function to perform a batch-mode simulation where it generates a lot of random networks and conducts robustness calculations and feed-forward/feedback loop examinations of them. This helps us to determine if the findings in real biological networks are valid in arbitrary random networks or not. We tested our plugin in two case studies based on two large-scale signaling networks and found interesting results regarding relationships between coherently coupled feed-forward/feedback loops and robustness. In addition, we verified whether or not those findings are consistently conserved in random networks through batch-mode simulations. Taken together, our plugin is expected to effectively investigate various relationships between dynamics and structural properties in large-scale networks. Our software tool, user manual and example datasets are freely available at http://panet-csc.sourceforge.net/.
Directory of Open Access Journals (Sweden)
Hung-Cuong Trinh
Full Text Available It has been a challenge in systems biology to unravel relationships between structural properties and dynamic behaviors of biological networks. A Cytoscape plugin named NetDS was recently proposed to analyze the robustness-related dynamics and feed-forward/feedback loop structures of biological networks. Despite such a useful function, limitations on the network size that can be analyzed exist due to high computational costs. In addition, the plugin cannot verify an intrinsic property which can be induced by an observed result because it has no function to simulate the observation on a large number of random networks. To overcome these limitations, we have developed a novel software tool, PANET. First, the time-consuming parts of NetDS were redesigned to be processed in parallel using the OpenCL library. This approach utilizes the full computing power of multi-core central processing units and graphics processing units. Eventually, this made it possible to investigate a large-scale network such as a human signaling network with 1,609 nodes and 5,063 links. We also developed a new function to perform a batch-mode simulation where it generates a lot of random networks and conducts robustness calculations and feed-forward/feedback loop examinations of them. This helps us to determine if the findings in real biological networks are valid in arbitrary random networks or not. We tested our plugin in two case studies based on two large-scale signaling networks and found interesting results regarding relationships between coherently coupled feed-forward/feedback loops and robustness. In addition, we verified whether or not those findings are consistently conserved in random networks through batch-mode simulations. Taken together, our plugin is expected to effectively investigate various relationships between dynamics and structural properties in large-scale networks. Our software tool, user manual and example datasets are freely available at http://panet-csc.sourceforge.net/.
Automated eigensystem realisation algorithm for operational modal analysis
Zhang, Guowen; Ma, Jinghua; Chen, Zhuo; Wang, Ruirong
2014-07-01
The eigensystem realisation algorithm (ERA) is one of the most popular methods in civil engineering applications for estimating modal parameters. Three issues have been addressed in the paper: spurious mode elimination, estimating the energy relationship between different modes, and automatic analysis of the stabilisation diagram. On spurious mode elimination, a new criterion, modal similarity index (MSI) is proposed to measure the reliability of the modes obtained by ERA. On estimating the energy relationship between different modes, the mode energy level (MEL) was introduced to measure the energy contribution of each mode, which can be used to indicate the dominant mode. On automatic analysis of the stabilisation diagram, an automation of the mode selection process based on a hierarchical clustering algorithm was developed. An experimental example of the parameter estimation for the Chaotianmen bridge model in Chongqing, China, is presented to demonstrate the efficacy of the proposed method.
Extended Supersymmetric BMS$_3$ algebras and Their Free Field Realisations
Banerjee, Nabamita; Lodato, Ivano; Mukhi, Sunil; Neogi, Turmoli
2016-01-01
We study $N=(2,4,8)$ supersymmetric extensions of the three dimensional BMS algebra (BMS$_3$) with most generic possible central extensions. We find that $N$-extended supersymmetric BMS$_3$ algebras can be derived by a suitable contraction of two copies of the extended superconformal algebras. Extended algebras from all the consistent contractions are obtained by scaling left-moving and right-moving supersymmetry generators symmetrically, while Virasoro and R-symmetry generators are scaled asymmetrically. On the way, we find that the BMS/GCA correspondence does not in general hold for supersymmetric systems. Using the $\\beta$-$\\gamma$ and the ${\\mathfrak b}$-${\\mathfrak c}$ systems, we construct free field realisations of all the extended super-BMS$_3$ algebras.
Realising traceable electrostatic forces despite non-linear balance motion
Stirling, Julian; Shaw, Gordon A.
2017-05-01
Direct realisation of force, traceable to fundamental constants via electromagnetic balances, is a key goal of the proposed redefinition of the international system of units (SI). This will allow small force metrology to be performed using an electrostatic force balance (EFB) rather than subdivision of larger forces. Such a balance uses the electrostatic force across a capacitor to balance an external force. In this paper we model the capacitance of a concentric cylinder EFB design as a function of the displacement of its free electrode, accounting for the arcuate motion produced by parallelogram linkages commonly used in EFB mechanisms. From this model we suggest new fitting procedures to reduce uncertainties arising from non-linear motion as well as methods to identify misalignment of the mechanism. Experimental studies on both a test capacitor and the NIST EFB validate the model.
Public choice economics and space policy: realising space tourism
Collins, Patrick
2001-03-01
Government space agencies have the statutory responsibility to suport the commercialisation of space activities. NASA's 1998 report "General Public Space Travel and Tourism" concluded that passenger space travel can start using already existing technology, and is likely to grow into the largest commercial activity in space: it is therefore greatly in taxpayers' economic interest that passenger space travel and accommodation industries should be developed. However, space agencies are doing nothing to help realise this — indeed, they are actively delaying it. This behaviour is predicted by 'public choice' economics, pioneered by Professors George Stigler and James Buchanan who received the 1982 and 1986 Nobel prizes for Economics, which views government organisations as primarily self-interested. The paper uses this viewpoint to discuss public and private roles in the coming development of a space tourism industry.
Free-field realisations of BMS$_3$ and super-BMS$_3$ algebras
Banerjee, Nabamita; Mukhi, Sunil; Neogi, Turmoli
2015-01-01
We construct an explicit realisation of the BMS$_3$ algebra with nonzero central charges using holomorphic free fields. This can be extended by the addition of chiral matter to a realisation having arbitrary values for the two independent central charges. We show that our construction naturally extends to a coupled SU(2)-BMS$_3$ system where the SU(2) Kac-Moody symmetry is realised via the Wakimoto representation, and to the supersymmetric BMS$_3$ algebra.
Equivalent realisation circuit for a class of non-ideal voltage-controlled memristors
Directory of Open Access Journals (Sweden)
Saihu Pan
2015-12-01
Full Text Available In this study, an equivalent realisation circuit with off-the-shelf components and devices is proposed, which can be used to equivalently implement a class of non-ideal voltage-controlled memristors. The mathematical models of the equivalent realisation circuit with three function arithmetic circuits are built and their fingerprints are analysed by the pinched hysteresis loops with bipolar periodic voltage stimuli. The numerical simulations are easily verified by experimental measurements, which indicate that when three function arithmetic circuits are linked, the equivalent realisation circuit can realise three non-ideal voltage-controlled memristors with different non-linearities.
Borré, Etienne; Rouen, Mathieu; Laurent, Isabelle; Magrez, Magaly; Caijo, Fréderic; Crévisy, Christophe; Solodenko, Wladimir; Toupet, Loic; Frankfurter, René; Vogt, Carla; Kirschning, Andreas; Mauduit, Marc
2012-12-14
In this study, a new pyridinium-tagged Ru complex was designed and anchored onto sulfonated silica, thereby forming a robust and highly active supported olefin-metathesis pre-catalyst for applications under batch and continuous-flow conditions. The involvement of an oxazine-benzylidene ligand allowed the reactivity of the formed Ru pre-catalyst to be efficiently controlled through both steric and electronic activation. The oxazine scaffold facilitated the introduction of the pyridinium tag, thereby affording the corresponding cationic pre-catalyst in good yield. Excellent activities in ring-closing (RCM), cross (CM), and enyne metathesis were observed with only 0.5 mol % loading of the pre-catalyst. When this powerful pre-catalyst was immobilized onto a silica-based cationic-exchange resin, a versatile catalytically active material for batch reactions was generated that also served as fixed-bed material for flow reactors. This system could be reused at 1 mol % loading to afford metathesis products in high purity with very low ruthenium contamination under batch conditions (below 5 ppm). Scavenging procedures for both batch and flow processes were conducted, which led to a lowering of the ruthenium content to as little as one tenth of the original values.
Energy Technology Data Exchange (ETDEWEB)
Risser, L.; Vincent, T.; Ciuciu, Ph. [NeuroSpin CEA, F-91191 Gif sur Yvette (France); Risser, L.; Vincent, T. [Laboratoire de Neuroimagerie Assistee par Ordinateur (LNAO) CEA - DSV/I2BM/NEUROSPIN (France); Risser, L. [Institut de mecanique des fluides de Toulouse (IMFT), CNRS: UMR5502 - Universite Paul Sabatier - Toulouse III - Institut National Polytechnique de Toulouse - INPT (France); Idier, J. [Institut de Recherche en Communications et en Cybernetique de Nantes (IRCCyN) CNRS - UMR6597 - Universite de Nantes - ecole Centrale de Nantes - Ecole des Mines de Nantes - Ecole Polytechnique de l' Universite de Nantes (France)
2009-07-01
In this paper, we present a first numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent, hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon it, classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, file proposed extrapolation method allows its to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust; to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible. (authors)
Realisation of a fast data storage and transfer system using a FPGA and an USB interface.
Leitner, Roman
2005-01-01
The Beam Loss Monitoring-system of the LHC is a complex measurement- and acquisition-system. The task of this system is to monitor the particle-beam and to request a dump in case of too big losses. Ionisation-chambers outside the magnets measure the losses of the beam and change this signal to a current signal. This signal will be converted to a frequency signal and prepared for the transmission to the surface inside a FPGA. On the surface the transmission is checked for errors. To analyse and observe the status of the particle-beam, this data must be transferred to a computer. This thesis covers the transmission, storage and visualisation of the data on the computer. The data are transmitted by an USB 2.0 module. The storage and visualisation is made in LabVIEW.
A realised volatility measurement using quadratic variation and dealing with microstructure effects
Directory of Open Access Journals (Sweden)
C du Toit
2006-12-01
Full Text Available A volatility measurement that overcomes the respective problems encountered when implementing the realised and Discrete Sine Transform volatility measurements is defined and discussed in this paper. First the shortcomings of these measurements are briefly discussed. Then a modified realised volatility measurement is defined and relevant theoretical results are derived. Finally simulation results are used to evaluate these three volatility measurements.
Impact of time-inhomogeneous jumps and leverage type effects on returns and realised variances
DEFF Research Database (Denmark)
Veraart, Almut
This paper studies the effect of time-inhomogeneous jumps and leverage type effects on realised variance calculations when the logarithmic asset price is given by a Lévy-driven stochastic volatility model. In such a model, the realised variance is an inconsistent estimator of the integrated...
Legal framework for e-research : realising the potential
2008-01-01
Legal Framework for e-Research: Realising the Potential provides an overview of key legal issues facing e-Research. Part One of this book considers the broader prospect and context of what e-Research will allow. Part Two looks more closely at the role law will play in the e-Research environment. Part Three focuses on the key issues of data exchange and data management highlighting important legal issues. Part Four reflects on the changing nature of Scholarly Communications while Part Five looks at the fundamental role of agreements for collaborative endeavour (contracts) in structuring collaboration and calls for greater consideration of way we can streamline the process. Part Six examines the role and operation of privacy law in an e-Research world while Part Seven posits a new approach to commercialisation that embraces the paradigm of open innovation. Part Eight looks at the international legal implications for e-Research and Part Nine considers the national survey we undertook on e-Research, collaborative...
Realisation of chiral symmetry in the domain model of QCD
Kalloniatis, Alexander C
2003-01-01
The domain model for the QCD vacuum has previously been developed and shown to exhibit confinement of quarks and strong correlation of the local chirality of quark modes and duality of the background domain-like gluon field. Quark fluctuations satisfy a chirality violating boundary conditions parametrized by a random chiral angle $\\alpha_j$ on the $j-th$ domain. The free energy of an ensemble of $N\\to\\infty$ domains depends on $\\{\\alpha_j, j=1... N\\}$ through the logarithm of the quark determinant. Its parity odd part is given by the axial anomaly. The anomaly contribution to the free energy suppresses continuous axial U(1) degeneracy in the ground state, leaving only a residual axial Z(2) symmetry. This discrete symmetry and flavour $SU(N_f)_L\\times SU(N_f)_R$ chiral symmetry in turn are spontaneously broken with a quark condensate arising due to the asymmetry of the spectrum of Dirac operator. In order to illustrate the splitting between the $\\eta'$ from octet pseudoscalar mesons realised in the domain mode...
Robust quantum state transfer via topologically protected edge channels in dipolar arrays
Dlaska, C.; Vermersch, B.; Zoller, P.
2017-03-01
We show how to realise quantum state transfer between distant qubits using the chiral edge states of a two-dimensional topological spin system. Our implementation based on Rydberg atoms allows to realise the quantum state transfer protocol in state-of-the-art experimental setups. In particular, we show how to adapt the standard state transfer protocol to make it robust against dispersive and disorder effects.
DEFF Research Database (Denmark)
Gorm Hansen, Birgitte
2012-01-01
as the analytical framework for descri bing the complex relationship between academic science and its so called “external” habitat. Although relational skills and adaptability do seem to be at the heart of successful research management, the key to success does not lie with the ability to assimilate to industrial...... knowledge", Danish research policy seems to have helped develop politically and economically "robust scientists". Scientific robustness is acquired by way of three strategies: 1) tasting and discriminating between resources so as to avoid funding that erodes academic profiles and push scientists away from...... and industrial intere sts. The paper concludes by stressing the potential danger of policy habitats who have promoted the evolution of robust scientists based on a competitive system where only the fittest survive. Robust scientists, it is argued, have the potential to become a new “invasive species...
Design and realisation of an audiovisual speech activity detector
Van Bree, K.C.
2006-01-01
For many speech telecommunication technologies a robust speech activity detector is important. An audio-only speech detector will givefalse positives when the interfering signal is speech or has speech characteristics. The modality video is suitable to solve this problem. In this report the approach
Energy Technology Data Exchange (ETDEWEB)
Fulop, L.
1998-10-09
We used micro-chip lasers developed in LETI to pump a miniature Optical Parametric Oscillator (OPO). The micro-chip lasers can be fabricated at very low cost, using collective fabrication processes. The micro-chip lasers we used are Nd:YAG lasers, passively Q-switched by a Cr{sup 4+}:YAG saturable absorber. They are pumped with 1 W standard laser diodes and emit pulses which characteristics are a few {mu}J energies and several kHz repetition rates. The main problem in pumping an OPO with such a micro-chip laser is to reach its oscillation threshold. We are calculated this threshold and showed that it will be impossible to pump an extra-cavity OPO with a micro-chip laser. We first worked with an extra-cavity OPO based on the non-critical-phase-matching conversion 1.064 {mu}m{yields}1.572 {mu}m + 3.293 {mu}m in a KTP crystal, pumped with a mJ energy laser. In spite of good results (low thresholds of 200 {mu}J) and as we have calculated, it was not be possible to pump such an OPO with our micro-chip lasers (10{mu}J maximum energies). We developed an intracavity micro-chip OPO (with the OPO inside the laser cavity). In this configuration, the OPO benefits from the intracavity laser intensity to reach the oscillation threshold. The micro-chip OPO emits about 10 ns pulses at 1.572 {mu}m with a few {mu}J energy at several kHz repetition rate. To our knowledge, we realised the first micro-chip-OPO using a 1 W standard diode pumped, passively Q-switched micro-chip laser. In order to improve the performances of the intracavity micro-chip-OPO, we developed a software for numerical modelling its operation. (author) 80 refs.
Robust Repetitive Controller for Fast AFM Imaging
Necipoglu, Serkan; Has, Yunus; Guvenc, Levent; Basdogan, Cagatay
2012-01-01
Currently, Atomic Force Microscopy (AFM) is the most preferred Scanning Probe Microscopy (SPM) method due to its numerous advantages. However, increasing the scanning speed and reducing the interaction forces between the probe's tip and the sample surface are still the two main challenges in AFM. To meet these challenges, we take advantage of the fact that the lateral movements performed during an AFM scan is a repetitive motion and propose a Repetitive Controller (RC) for the z-axis movements of the piezo-scanner. The RC utilizes the profile of the previous scan line while scanning the current line to achieve a better scan performance. The results of the scanning experiments performed with our AFM set-up show that the proposed RC significantly outperforms a conventional PI controller that is typically used for the same task. The scan error and the average tapping forces are reduced by 66% and 58%, respectively when the scan speed is increased by 7-fold.
Public-private Partnership in the Context of Realisation of the State Financial Policy
Directory of Open Access Journals (Sweden)
Ostapenko Victoriia M.
2014-02-01
Full Text Available In the result of the study the article analyses modern tendencies of development of economy of Ukraine. It marks out problems connected with realisation of the state financial policy. It considers the essence of the state financial policy, its directions (such as budget-tax and monetary-credit, structural components and tasks. It emphasises the place of the public-private partnership as an instrument of realisation of the financial policy. It justifies tasks in the process of realisation of goals of the modern financial policy, which could be carried out with the help of the public-private partnership. The prospect of further studies in this direction is formation of practical recommendations on the use of the public-private partnership in the process of realisation of the state financial policy. Further improvement of the public-private partnership is connected with development of efficient mechanisms of its introduction and optimisation of its financial structure.
Banerjee, S; Grebogi, C; Banerjee, Soumitro; Yorke, James A.; Grebogi, Celso
1998-01-01
It has been proposed to make practical use of chaos in communication, in enhancing mixing in chemical processes and in spreading the spectrum of switch-mode power suppies to avoid electromagnetic interference. It is however known that for most smooth chaotic systems, there is a dense set of periodic windows for any range of parameter values. Therefore in practical systems working in chaotic mode, slight inadvertent fluctuation of a parameter may take the system out of chaos. We say a chaotic attractor is robust if, for its parameter values there exists a neighborhood in the parameter space with no periodic attractor and the chaotic attractor is unique in that neighborhood. In this paper we show that robust chaos can occur in piecewise smooth systems and obtain the conditions of its occurrence. We illustrate this phenomenon with a practical example from electrical engineering.
Čίžek, Pavel; Härdle, Wolfgang Karl
2006-01-01
Econometrics often deals with data under, from the statistical point of view, non-standard conditions such as heteroscedasticity or measurement errors and the estimation methods need thus be either adopted to such conditions or be at least insensitive to them. The methods insensitive to violation of certain assumptions, for example insensitive to the presence of heteroscedasticity, are in a broad sense referred to as robust (e.g., to heteroscedasticity). On the other hand, there is also a mor...
George, Angela; Riddell, Daniel; Seal, Sheila; Talukdar, Sabrina; Mahamdallie, Shazia; Ruark, Elise; Cloke, Victoria; Slade, Ingrid; Kemp, Zoe; Gore, Martin; Strydom, Ann; Banerjee, Susana; Hanson, Helen; Rahman, Nazneen
2016-07-13
Advances in DNA sequencing have made genetic testing fast and affordable, but limitations of testing processes are impeding realisation of patient benefits. Ovarian cancer exemplifies the potential value of genetic testing and the shortcomings of current pathways to access testing. Approximately 15% of ovarian cancer patients have a germline BRCA1 or BRCA2 mutation which has substantial implications for their personal management and that of their relatives. Unfortunately, in most countries, routine implementation of BRCA testing for ovarian cancer patients has been inconsistent and largely unsuccessful. We developed a rapid, robust, mainstream genetic testing pathway in which testing is undertaken by the trained cancer team with cascade testing to relatives performed by the genetics team. 207 women with ovarian cancer were offered testing through the mainstream pathway. All accepted. 33 (16%) had a BRCA mutation. The result informed management of 79% (121/154) women with active disease. Patient and clinician feedback was very positive. The pathway offers a 4-fold reduction in time and 13-fold reduction in resource requirement compared to the conventional testing pathway. The mainstream genetic testing pathway we present is effective, efficient and patient-centred. It can deliver rapid, robust, large-scale, cost-effective genetic testing of BRCA1 and BRCA2 and may serve as an exemplar for other genes and other diseases.
Experimental Realisation of a Thermal Squeezed State of Levitated Optomechanics
Rashid, Muddassar; Bateman, James; Vovrosh, Jamie; Hempston, David; Kim, M S; Ulbricht, Hendrik
2016-01-01
We experimentally squeeze the thermal motional state of an optically levitated nanosphere, by fast switching between two trapping frequencies. The measured phase space distribution of our particle shows the typical shape of a squeezed thermal state, from which we infer up to 2.7dB of squeezing along one motional direction. The experiment features a large number of thermal excitations, therefore remaining in the classical regime. Nevertheless, we argue that the manipulation scheme described here could be used to achieve squeezing below the zero-point level, if preceded by ground state cooling of the levitated mechanical oscillator. Additionally, a higher degree of squeezing could in principle be achieved by repeating the frequency-switching protocol multiple times.
Robust trajectory tracking: differential game/cheap control approach
Turetsky, Vladimir; Glizer, Valery Y.; Shinar, Josef
2014-11-01
A robust trajectory tracking problem is treated in the framework of a zero-sum linear-quadratic differential game of a general type. For the cheap control version of this game, a novel solvability condition is derived. The sufficient condition, guaranteeing that the tracking problem is solved by the optimal strategy of the minimiser in the cheap control game, is established. The boundedness of the time realisations of this strategy is analysed. An illustrative example is presented.
DEFF Research Database (Denmark)
Gorm Hansen, Birgitte
The concepts of “socially robust knowledge” and “mode 2 knowledge production” (Nowotny 2003, Gibbons et al. 1994) have migrated from STS into research policy practices. Both STS-scholars and policy makers have been known to propomote the idea that the way forward for today’s scientist is to jump...... from the ivory tower and learn how to create high-flying synergies with citizens, corporations and governments. In STS as well as in Danish research policy it has thus been argued that scientists will gain more support and enjoy greater success in their work by “externalizing” their research...... and adapting their interests to the needs of outside actors. However, when studying the concrete strategies of such successful scientists, matters seem a bit more complicated. Based on interviews with a plant biologist working in GMO the paper uses the biological concepts of field participants...
DEFF Research Database (Denmark)
Aanæs, Henrik; Fisker, Rune; Åström, Kalle;
2002-01-01
Factorization algorithms for recovering structure and motion from an image stream have many advantages, but they usually require a set of well-tracked features. Such a set is in generally not available in practical applications. There is thus a need for making factorization algorithms deal...... effectively with errors in the tracked features. We propose a new and computationally efficient algorithm for applying an arbitrary error function in the factorization scheme. This algorithm enables the use of robust statistical techniques and arbitrary noise models for the individual features....... These techniques and models enable the factorization scheme to deal effectively with mismatched features, missing features, and noise on the individual features. The proposed approach further includes a new method for Euclidean reconstruction that significantly improves convergence of the factorization algorithms...
Energy Technology Data Exchange (ETDEWEB)
Nacer-Khodja, M.; Medjaher, M.; Menad, F.; Haffaf, E.M. [Service de medecine nucleaire, hopital central de l' armee, Alger, (Algeria)
2009-05-15
The objective was to have the choice between the different protocols of parathyroid scintigraphy realisation, for a population having a nodule (or multi nodules) goiter with the non availability to iodine 123. The factorial analysis of a dynamic sequence with sestamibi {sup 99m}Tc is the most used protocol in first intention for a population with a nodule goiter in the lack of iodine 123 during the realization of a parathyroid scintigraphy. (N.C.)
DEFF Research Database (Denmark)
Veraart, Almut
2011-01-01
This paper studies the impact of jumps on volatility estimation and inference based on various realised variation measures such as realised variance, realised multipower variation and truncated realised multipower variation. We review the asymptotic theory of those realised variation measures and...... of a highly active jump process. Finally, we investigate the impact of jumps on inference on volatility empirically, where we study high frequency data from the Standard & Poor’s Depository Receipt (SPY)....
Muller, M.
2007-01-01
There is a new generation of nuclear power stations on the drawing board. They must be sustainable as well as safe and cost-effective. Can these ambitions be realised? The sustainable power stations are less safe, and the safe ones are less sustainable.
Realising Graduate Attributes in the Research Degree: The Role of Peer Support Groups
Stracke, Elke; Kumar, Vijay
2014-01-01
This paper discusses the role of peer support groups (PSGs) in realising graduate attributes in the research degree. The literature indicates that top-down embedding of graduate attributes has met with only limited success. By taking a bottom-up approach, this paper shows that PSGs offer an opportunity to improve the graduate attribute outcomes of…
Autoethnographic Realisation of Legitimacy of Voice: A Poetic Trail of Forming Researcher Identity
Directory of Open Access Journals (Sweden)
Thirusha Naidu
2014-01-01
Full Text Available During my research with home-based care volunteers in South Africa I used autoethnography and poetic reflection to document the parallel realisation of my changing identity as a researcher and the home-based care volunteers' realisation of their identity as significant contributors to the HIV/AIDS care and support networks in their community. I explored how the concepts of space and witnessing were operative in the realisation of a legitimate identity for the participants and me. Physical space or distance from familiar environments, experiences and ideas promoted alternative perspectives and stimulated the development of an understanding of personal identity. Dialogical space created through engagement with others encouraged identity development in both different and similar ways for me as a researcher and the participants. In this article, I recount my role as a witness to the participants’ realisation of identity whilst concurrently being witnessed by others in the process of developing my identity as a researcher. Witnessing is recognised as acknowledgement and affirmation in the process of identity development. A series of poems written during and after the primary data collection illustrate aspects of the discussion. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1401212
'Lived Islam' in India and Bangladesh : negotiating religion to realise reproductive aspirations
Sahu, Biswamitra; Hutter, Inge
2012-01-01
This paper seeks to answer the question of how Muslim women interpret and negotiate religion in order to realise their reproductive aspirations. A close reading of lived experiences of 32 Muslim women from a varied educational background yields a wider perspective of the different interpretations of
Legislative and other measures taken by government to realise the right of children to shelter
Directory of Open Access Journals (Sweden)
I Mc Murray
2004-06-01
Full Text Available The Constitution of the Republic of South Africa , 1996 entrenches numerous socio-economic rights. One of these socio-economic rights is contained in section 26 that grants everyone the right to have access to adequate housing and section 28 that grants every child the additional right to basic shelter among others. This article aims to examine the legislative and other measures taken by the state to realise the right to shelter of children. Firstly, the legislative measures taken specifically for the realisation of children's right to basic shelter as envisaged by section 28(1(c will be discussed. Thereafter attention will be drawn to those measures taken to ensure the progressive realisation of section 26. Section 26 provides everyone, including children, the right of access to adequate housing. Therefore, every measure taken to realise section 26 is indirectly applicable to the realisation of section 28(1(c and children's right to basic shelter.The conclusion may be drawn that most of the discussed legislative and other measures are aimed at realising everyone's right of access to adequate housing, this includes children. However, most of these measures make little mention of the specific right of children to basic shelter. It is regarded as inclusive in the overall application of the legislation. Once again, it must be stressed that these legislative and other measures, in order to comply with the standard of reasonableness, must regard the interest of children to be paramount. If such legislation does not provide for the interest of children as a vulnerable group, it can be argued that the relevant legislative measure is not constitutionally valid.It is submitted that national government must recognise the importance of the role of local government, and local government should increasingly assume policy-making and implementation powers in their area. This will go a long way to building local capacity to function as effective development
Realising effective theories of tribrid inflation: Are there effects from messenger fields?
Antusch, Stefan
2015-01-01
Tribrid inflation is a variant of supersymmetric hybrid inflation in which the inflaton is a matter field (which can be charged under gauge symmetries) and inflation ends by a GUT-scale phase transition of a waterfall field. These features make tribrid inflation a promising framework for realising inflation with particularly close connections to particle physics. Superpotentials of tribrid inflation involve effective operators suppressed by some cutoff scale, which is often taken as the Planck scale. However, these operators may also be generated by integrating out messenger superfields with masses below the Planck scale, which is in fact quite common in GUT and/or flavour models. The values of the inflaton field during inflation can then lie above this mass scale, which means that for reliably calculating the model predictions one has to go beyond the effective theory description. We therefore discuss realisations of effective theories of tribrid inflation and specify in which cases effects from the messenge...
Directory of Open Access Journals (Sweden)
Lena M. Wallenhorst
2015-01-01
Full Text Available We report on the characteristics of aluminium trihydrate filled poly(methyl methacrylate composite (PMMA/ATH coatings realised by plasma deposition at atmospheric pressure. For this purpose, PMMA/ATH powder was fed to a plasma jet where the process and carrier gas was compressed air. The deposited coatings were investigated by X-ray photoelectron spectroscopy and water contact angle measurements. Further, the raw material was characterised before deposition. It was found that, with respect to the raw material, aluminium was uncovered in the course of the plasma deposition process which can be explained by plasma-induced etching of the PMMA matrix. As a result, the wettability of plasma-deposited PMMA/ATH was significantly increased. Even though a uniform coating film could not be realised as ascertained by confocal laser scanning microscopy, the deposited coatings feature notably enhanced characteristics which could be advantageous for further processing.
Minimal state space realisation of continuous-time linear time-variant input-output models
Goos, J.; Pintelon, R.
2016-04-01
In the linear time-invariant (LTI) framework, the transformation from an input-output equation into state space representation is well understood. Several canonical forms exist that realise the same dynamic behaviour. If the coefficients become time-varying however, the LTI transformation no longer holds. We prove by induction that there exists a closed-form expression for the observability canonical state space model, using binomial coefficients.
Realising Universal Suffrage in Hong Kong after the Standing Committee's Decision
Young, SNM
2014-01-01
Of all the preconditions to realising universal suffrage of Hong Kong’s Chief Executive in 2017, the most challenging is getting two-thirds of the 70 legislators to agree on a reform proposal. On 31 August 2014, the Standing Committee of the National People’s Congress made this challenge even more difficult by imposing restrictive and controlling conditions on the nomination process. The decision sparked unprecedented protests and acts of civil disobedience on the streets of Hong Kong in Sept...
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard
2011-01-01
robust design as well as strategies for maintaining the robustness of existing structures throughout their service life. This paper describes an overall theoretical framework for assessing robustness of structures developed within WG1 “Robustness of structures”. Robustness can be defined in different......An important aspect of the COST Action TU0601 “Robustness of structures” concerns the development of a theoretically sound basis for the assessment of robustness and acceptance criteria for structural robustness which can form the basis for development of practical relevant methods for ensuring...
Ensuring the Process of Realisation of Financial Planning of Banking Activity
Directory of Open Access Journals (Sweden)
Kirkach Svitlana M.
2014-03-01
Full Text Available The article studies theoretical aspects of the process of realisation of financial planning of the bank’s activity and identifies and justifies its six main stages: 1 goal formation stage; 2 preparation stage; 3 assessment; 4 financial plan approval; 5 financial plan execution, and 6 stage of the financial plan monitoring, control and adjustment. The above sequence of stages of the process of realisation of financial planning of the bank’s activity allows a trustworthy assessment of the bank’s activity environment, formation of specific goals and tasks of the bank’s activity, and also to determine the ways of their achievement, and so on. The result of the process of realisation of financial planning of the bank’s activity is the bank’s financial plan, which is proposed to divide into four sub-sections: plan of the bank’s assets and liabilities; plan of the bank’s receipts and expenditures; plan of the bank’s cash flows; and plan of forecast values of basic financial indicators of the bank’s activity.
Realising effective theories of tribrid inflation: are there effects from messenger fields?
Energy Technology Data Exchange (ETDEWEB)
Antusch, Stefan [Department of Physics, University of Basel,Klingelbergstr. 82, CH-4056 Basel (Switzerland); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805 München (Germany); Nolde, David [Department of Physics, University of Basel,Klingelbergstr. 82, CH-4056 Basel (Switzerland)
2015-09-22
Tribrid inflation is a variant of supersymmetric hybrid inflation in which the inflaton is a matter field (which can be charged under gauge symmetries) and inflation ends by a GUT-scale phase transition of a waterfall field. These features make tribrid inflation a promising framework for realising inflation with particularly close connections to particle physics. Superpotentials of tribrid inflation involve effective operators suppressed by some cutoff scale, which is often taken as the Planck scale. However, these operators may also be generated by integrating out messenger superfields with masses below the Planck scale, which is in fact quite common in GUT and/or flavour models. The values of the inflaton field during inflation can then lie above this mass scale, which means that for reliably calculating the model predictions one has to go beyond the effective theory description. We therefore discuss realisations of effective theories of tribrid inflation and specify in which cases effects from the messenger fields are expected, and under which conditions they can safely be neglected. In particular, we point out how to construct realisations where, despite the fact that the inflaton field values are above the messenger mass scale, the predictions for the observables are (to a good approximation) identical to the ones calculated in the effective theory treatment where the messenger mass scale is identified with the (apparent) cutoff scale.
Evaluation of realised energy savings with simulation models. A new policy tool for the Netherlands
Energy Technology Data Exchange (ETDEWEB)
Boonekamp, P.G.M. [ECN Policy Studies, Petten (Netherlands)
2013-01-15
This report describes a new analysis tool for the evaluation of realised energy savings, and effects of savings policy, in the Netherlands. It aims to meet the information needs of policymakers, both at national and EU level, using the monitoring results of the NL Agency. The system builds on the Protocol Monitoring Energy Savings to calculate realised savings. The innovation consists of the option to adjust energy models per sector, as already used for scenario analysis, to simulate past developments. The simulations can estimate total savings and assess the contribution of policy measures. The detailed simulation approach also enables the decomposition of energy trends into volume-effects due to growth, structural effects such as fuel substitution and import/exports, and various saving effects. As the modeling system is already used for the analysis of future trends, it enables a good comparison between ex-ante (expected) savings and ex-post (realised) savings. Finally, the system enables a faster delivery of calculation results than presently is the case.
Directory of Open Access Journals (Sweden)
Krush Peter V.
2014-01-01
Full Text Available The goal of the article lies in building a functional model of management of transaction expenses of an enterprise with specification of stages of realisation of planning functions in an organisation. In the result of the study the article marks out functions of management of transaction expenses, which ensure transformation of incoming (financial resources into outgoing ones (optimised transaction expenses. The article identifies stages of realisation of “Planning transaction expenses” and “Organisation of management of transaction expenses” functions. It characterises in detail responsibilities of enterprise subdivisions that deal with management of transaction expenses. It establishes that the original element of the planning function is the budget of transaction expenses for a planning period and organisation – job descriptions of employees with detailed description of their duties and authorities, rights and obligations. The prospect of further scientific developments is study of stages of realisation of such management functions as “Motivation of personnel on rational use of funds and management of transaction expenses”, “Control over the state of management of transaction expenses” and “Regulation of the process of management of transaction expenses” of enterprises.
DEFF Research Database (Denmark)
Veraart, Almut
and present a new estimator for the asymptotic ‘variance’ of the centered realised variance in the presence of jumps. Next, we compare the finite sample performance of the various estimators by means of detailed Monte Carlo studies where we study the impact of the jump activity, the jump size of the jumps...... in the price and the presence of additional independent or dependent jumps in the volatility on the finite sample performance of the various estimators. We find that the finite sample performance of realised variance, and in particular of the log–transformed realised variance, is generally good, whereas...
Methods for robustness programming
Olieman, N.J.
2008-01-01
Robustness of an object is defined as the probability that an object will have properties as required. Robustness Programming (RP) is a mathematical approach for Robustness estimation and Robustness optimisation. An example in the context of designing a food product, is finding the best composition
The robust regulation problem with robust stability
Cevik, M.K.K.; Schumacher, J.M.
1999-01-01
Among the most common purposes of control are the tracking of reference signals and the rejection of disturbance signals in the face of uncertainties. The related design problem is called the `robust regulation problem'. Here we investigate the trade-off between the robust regulation constraint and
Robust control of an aircraft model
Energy Technology Data Exchange (ETDEWEB)
Werner, H. [Bochum Univ. (Germany). Fakultaet fuer Elektrotechnik
1999-12-01
A new multimodel approach to robust controller design is illustrated by a practical application: for a laboratory aircraft model, a robust controller is designed simultaneously for normal operating conditions and for propeller failure. Based on a linear model for each operating mode, an LMI formulation of the problem and convex programming are used to search for a state feedback controller which achieves the objective. This state feedback design is then realized simultaneously in both operating modes by a controller which is based on fast output sampling. Robust performance is demonstrated by experimental results. (orig.)
Robust control of an aircraft model
Energy Technology Data Exchange (ETDEWEB)
Werner, H. (Bochum Univ. (Germany). Fakultaet fuer Elektrotechnik)
1999-01-01
A new multimodel approach to robust controller design is illustrated by a practical application: for a laboratory aircraft model, a robust controller is designed simultaneously for normal operating conditions and for propeller failure. Based on a linear model for each operating mode, an LMI formulation of the problem and convex programming are used to search for a state feedback controller which achieves the objective. This state feedback design is then realized simultaneously in both operating modes by a controller which is based on fast output sampling. Robust performance is demonstrated by experimental results. (orig.)
Robust design of large-displacement compliant mechanisms
Directory of Open Access Journals (Sweden)
B. S. Lazarov
2011-08-01
Full Text Available The aim of this article is to introduce a new topology optimisation formulation for optimal robust design of Micro Electro Mechanical Systems. Mesh independence in topology optimisation is most often ensured by using filtering techniques, which result in transition grey regions difficult to interpret in practical realisations. This problem has been alleviated recently by projection techniques, but these destroy the mesh independence introduced by the filters and result in single node connected hinges. Such features in the design are undesirable as they are not robust with respect to geometric manufacturing errors (such as under/over etching. They can be avoided by optimising for several design realisations which take into account the possible geometry errors. The design variations are modelled with the help of random variables. The proposed stochastic formulation for the design variations results in nearly black and white mechanism designs, robust with respect to uncertainties in the production process, i.e. without any hinges or small details which can create manufacturing difficulties.
Herbert: Design and Realisation of an full-sized anthropometrically correct humanoid robot
Directory of Open Access Journals (Sweden)
Brennand ePierce
2015-06-01
Full Text Available In this paper we present the development of a new full-sized anthropometrically correct humanoid robot Herbert. Herbert has 33 DOFs: 1 29 active DOFs (2 × 4 in the legs, 2 × 7 in the arms, 4 in the waist and 3 in the head; 2 4 passive DOFs (2 × 2 in the ankles. We present the objectives of the design and the development of our system, the hardware (mechanical, electronics as well as the supporting software architecture that encompasses the realisation of the complete humanoid system.Several key elements, that have to be taken into account in our approach to keep the costs low while ensuring high-performance, will be presented. In realising Herbert we applied a modular design for the overall mechanical structure. Two core mechanical module types make up the main structural elements of Herbert: 1 small compact mechanical drive modules; and 2 compliant mechanical drive modules. The electronic system of Herbert, which is based on two different types of motor control boards and an FPGA module with a central controller, is discussed. The software architecture is based on ROS with a number of sub nodes used for the controller. All these supporting components have been important in the development of the complete system.Finally, we present results showing our robot’s performances: demonstrating the behaviour of the compliant modules, the ability of tracking a desired position/velocity as well as a simple torque controller. We also evaluate our custom communication system. Additionally, we demonstrate Herbert balancing and squatting to show its performance. Moreover, we also show the simplicity of the higher level supporting software framework in realising new behaviours. All in all, we show that our system is compact and able to achieve comparable human performances and has human proportions while being low cost.
Donor/Acceptor Mixed Self-Assembled Monolayers for Realising a Multi-Redox-State Surface.
Casado-Montenegro, Javier; Marchante, Elena; Crivillers, Núria; Rovira, Concepció; Mas-Torrent, Marta
2016-06-17
Mixed molecular self-assembled monolayers (SAMs) on gold, based on two types of electroactive molecules, that is, electron-donor (ferrocene) and electron-acceptor (anthraquinone) molecules, are prepared as an approach to realise surfaces exhibiting multiple accessible redox states. The SAMs are investigated in different electrolyte media. The nature of these media has a strong impact on the types of redox processes that take place and on the redox potentials. Under optimised conditions, surfaces with three redox states are achieved. Such states are accessible in a relatively narrow potential window in which the SAMs on gold are stable. This communication elucidates the key challenges in fabricating bicomponent SAMs as electrochemical switches.
Digraphs Structures Corresponding to the Analogue Realisation of Fractional Continuous-Time System
MARKOWSKI, Konrad A.
2017-01-01
This paper presents a method of the determination of a minimal realisation of the fractional continuous-time linear system. For the proposed method, a digraph-based algorithm was constructed. In this paper, we have shown how we can perform the transfer matrix using electrical circuits consisting of resistances, capacitance and source voltages. We have also shown how after using the constant phase element method we can realize such a system. The proposed method was discussed and illustrated with some theoretical and practical numerical examples.
DEFF Research Database (Denmark)
Larsen, Niels Martin; Egholm Pedersen, Ole; Pigram, Dave
2012-01-01
of complex geometry. In two full-scale experiments, grid shell structures have been designed and built at Aarhus School of Architecture and the University of Technology, Sydney, in 2011 and 2012. The novel design method is described as an iterative process, negotiating both physical and digital constraints....... This involves consideration of the relations between geometry and technique, as well as the use of form-finding and simulation algorithms for shaping and optimising the shape of the structure. Custom-made scripts embedded in 3D-modeling tools were used for producing the information necessary for realising...... the construction comprised of discrete concrete elements....
An Indoor Positioning Realisation for GSM using Fingerprinting and kNN
Directory of Open Access Journals (Sweden)
A. Anastasijević
2013-06-01
Full Text Available Positioning in public land mobile networks has become increasingly popular over the past years with the development of more sophisticated mobile equipment and standards. New services which rely on location information have been developed, such as emergency call localization, navigation, location sensitive commercials/ billing, etc. This paper investigates one practical realisation of an indoor positioning model for GSM (Global System for Mobile Communications networks, based on the received signal strength (RSS and fingerprinting method. The achieved results are well within international localization accuracy requirements for emergency services, confirming great potential of the approach.
Sustainable technological process as an element of the sustainable development strategy realisation
Directory of Open Access Journals (Sweden)
R. Nowosielski
2011-10-01
Full Text Available Purpose: The aim of this work is a presentation of the possibility of the sustainable development conception realisation through the sustainable technological processes designing and implementation.Design/methodology/approach: The article includes analysis and estimation of the nickel and chromium coated on the metal elements. In order to modernization of the real process in direction to the sustainable process, the technical solutions which minimise influence on the environment of galvanic treatment process were presented.Findings: The sustainable technological process reduces the achievement of the sustainable development to small area analysis which is the technological process, what makes possible the quantitative estimation (in the internal area of technology.Research limitations/implications: The definition, the model of the sustainable technology and the sustainable development conception are relative and they have not clear character. It means there is no possibility of absolutely the best technology or technological process determination. Because of that we can only design the better process in the comparison with another with regard to adequate criteria.Practical implications: The solution presented in the paper can apply in the industry to estimation and selection of a group of technological processes which characterise different environmental influences.Originality/value: The paper presents search for the sustainable technological processes according to proposed procedure of the sustainable technology design and implementation. Application of the sustainable technological processes in the local scale can leads to the sustainable development conception realisation in the global scale.
Vlajic, J.V.
2012-01-01
The operation of supply chains (SCs) has for many years been focused on efficiency, leanness and responsiveness. This has resulted in reduced slack in operations, compressed cycle times, increased productivity and minimised inventory levels along the SC. Combined with tight tolerance settings for the realisation of logistics and production processes, this has led to SC performances that are frequently not robust. SCs are becoming increasingly vulnerable to disturbances, which can decrease the...
Energy Technology Data Exchange (ETDEWEB)
Haghighi, Behzad, E-mail: haghighi@iasbs.ac.i [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195 - 1159, Gava Zang, Zanjan (Iran, Islamic Republic of); Hamidi, Hassan [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195 - 1159, Gava Zang, Zanjan (Iran, Islamic Republic of); Gorton, Lo [Institute of Chemistry, Lund University, P.O. Box 124, S-221 00 Lund (Sweden)
2010-06-30
A robust and stable film comprising n-octylpyridinum hexafluorophosphate ([C{sub 8}Py][PF{sub 6}]) and 1:12 phosphomolybdic acid (PMo{sub 12}) was prepared on glassy carbon electrodes modified with multiwall carbon nanotubes (GCE/MWCNTs) by dip-coating. The cyclic voltammograms of the GCE/MWCNTs/[C{sub 8}Py][PF{sub 6}]-PMo{sub 12} showed three well-defined pairs of redox peaks due to the PMo{sub 12} system. The surface coverage for the immobilized PMo{sub 12} and the average values of the electron transfer rate constant for three pairs of redox peaks were evaluated. The GCE/MWCNTs/[C{sub 8}Py][PF{sub 6}]-PMo{sub 12} showed great electrocatalytic activity towards the reduction of H{sub 2}O{sub 2} and iodate. The kinetic parameters of the catalytic reduction of hydrogen peroxide and iodate at the electrode surface and analytical features of the sensor for amperometric determination of hydrogen peroxide and iodate were evaluated.
BFROST: binary features from robust orientation segment tests accelerated on the GPU
CSIR Research Space (South Africa)
Cronje, J
2011-11-01
Full Text Available , scalable, rotation invariant, fast to compute in parallel and maintains low memory consumption. The proposed method demonstrates good robustness and very fast computation times, making it usable in real-time applications....
3D Information System of Historical Site – Proposal and Realisation of a Functional Prototype
Directory of Open Access Journals (Sweden)
J. Hodač
2005-01-01
Full Text Available The development of methods for 3D data acquisition, together with progress in information technologies raises the question of creating and using 3D models and 3D information systems (IS of historical sites and buildings. This paper presents the current state of the “Live Theatre” project. The theme of the project is the proposal and realisation of a 3D IS of the baroque theatre at Eeský Krumlov castle (UNESCO site.The project is divided into three main stages – creation of a 3D model, proposal of a conception for a 3D IS, and realisation of a functional prototype. 3D data was acquired by means of photogrammetric and surveying methods. An accurate 3D model (photo-realistic, textured was built up with MicroStation CAD system. The proposal of a conception of a 3D IS was the main outcome of the author’s dissertation. The essential feature of the proposed conception is the creation of subsystems targeted on three spheres – management, research and presentation of the site. The functionality of each subsystem is connected with its related sphere; however, each subsystem uses the same database. The present stage of the project involves making a functional prototype (with sample data. During this stage we are working on several basic technological topics. At present we are concerned with 3D data, its formats, format conversions (e.g. DGN _ VRML and its connection to other types of data. After that, we will be seeking a convenient technical solution based on network technologies (Internet and an appropriate layout for the data (database. The project is being carried out in close co-operation with the administration of the castle and some other partners. This stage of the project will be completed in December 2005.A functional prototype and the information acquired by testing it will form the basis for the final proposal of a complex IS of a historical site. The final proposal and appropriate technology will be the outcome of the project. The
DEFF Research Database (Denmark)
Badie, Farshad
2016-01-01
Learning is the reflective activity that enables the learner to draw upon her/his previous experiences and background knowledge to conceptualise, realise, understand and evaluate the present, so as to shape her/his future actions and to construct and develop new knowledge for her(him)self. Learning...... is a significant part in the use of reasons and languages. My desired semantic structure will provide a structural representation of the learners' developing conceptions of learning that could support a kind of top-level ontology, i.e., an ontology representing the learners’ developing conceptions of learning....... This research will conceptually focus on multiple categories through the adult learners’ developing conceptions of learning. The focus will be on different categories from the basic conceptions to excellent ones. I will take an appropriate model of students’ developing conceptions of learning into my...
A string realisation of Ω-deformed Abelian N=2⁎ theory
Directory of Open Access Journals (Sweden)
Carlo Angelantonj
2017-10-01
Full Text Available The N=2⁎ supersymmetric gauge theory is a massive deformation of N=4, in which the adjoint hypermultiplet gets a mass. We present a D-brane realisation of the (non-Abelian N=2⁎ theory, and compute suitable topological amplitudes, which are expressed as a double series expansion. The coefficients determine couplings of higher-dimensional operators in the effective supergravity action that involve powers of the anti-self-dual N=2 chiral Weyl superfield and of self-dual gauge field strengths superpartners of the D5-brane coupling modulus. In the field theory limit, the result reproduces the Nekrasov partition function in the two-parameter Ω-background, in agreement with a recent proposal.
Directory of Open Access Journals (Sweden)
Stratan Dmytro I.
2013-03-01
Full Text Available The article states that the socio-economic development of a region rests on the higher-than-anticipated growth of its infrastructure. Formation of the social infrastructure of a region is based on practical realisation of social priorities directed at a higher satisfaction of needs of the population in social services. One of the mechanisms in development of social infrastructure is the state-private partnership. The article provides theoretical and methodical aspects of development of instruments of managing investment activity in Russian regions and levelling of territorial heterogeneity of availability of social objects on the basis of use of the state-private partnership (SPP. The article conducts assessment of possibilities of use of SPP models in the social sphere, regional economy and management of state property.
Khayat, Olfa; Kilani, Afef; Chedly-Debbiche, Achraf; Zeddini, Abdelfattah; Gargouri, Dalila; Kharrat, Jamel; Souissi, Adnene; Ghorbel, Abdel Jabbar; Ben Ayed, Mohamed; Ben Khelifa, Habib
2006-06-01
It's a prospective study leaded between September 1997 and july 1999 (23 months ) in 75 patients with duodenal ulcer and positif for Helicobacter pylori. All patients had a first endoscopy with antral, fundic and duodenal biopsies, followed one month later by a second control fibroscopy with biopsies of the same sites. A total of 420 biopsies was realised. Chronic gastritis was evaluated according to sydney system. Patients was divided by randomisation in 4 groups. Every group was received a different therapeutic association. The results was conform to liberation concering activity 80%, intestinal metaplasia 12%. inflammation 100%. Atrophy was observed in 56% of cases, this percentage is variable in literature; chronic gastritis was predominant in antre relatively to fundus (pomeprazol, amoxcillin, metronidazol by comparison with the others 3 groups (p<0.005).
Recent developments in thermal leptogenesis: the role of flavours in various seesaw realisations
Josse-Michaux, Francois-Xavier
2008-01-01
In this thesis, we study the role of flavours in leptogenesis. In a first time, we review the so-called one flavour picture, where only the lightest right-handed neutrino is taken into account, and where lepton flavours are neglected. After having showed why and how lepton flavours should be included in the computation of the lepton asymmetry, we study their effect in the type I seesaw model, as well as in the type I+II seesaw model, in a specific SO(10) unification realisation. In this model, besides flavours effects, we show that the inclusion of the second lightest right-handed neutrino, together with an accurate description of charged fermions masses, are necessary to make leptogenesis work.
Gravitational Waves from the Phase Transition of a Non-linearly Realised Electroweak Gauge Symmetry
Kobakhidze, Archil; Yue, Jason
2016-01-01
Within the Standard Model with non-linearly realised electroweak symmetry, the LHC Higgs boson may reside in a singlet representation of the gauge group. Several new interactions are then allowed, including anomalous Higgs self-couplings, which may drive the electroweak phase transition to be strongly first-order. In this paper we investigate the cosmological electroweak phase transition in a simplified model with an anomalous Higgs cubic self- coupling. We look at the feasibility of detecting gravitational waves produced during such a transition in the early universe by future space-based experiments. We find that for the range of relatively large cubic couplings, $111~{\\rm GeV}~ \\lesssim |\\kappa| \\lesssim 118~{\\rm GeV}$, $\\sim $mHz frequency gravitational waves can be observed by eLISA, while BBO will potentially be able to detect waves in a wider frequency range, $0.1-10~$mHz.
How Large-Scale Civil Engineering Projects Realise the Potential of a City (1/3)
CERN. Geneva
2012-01-01
In this series of three special lectures, leading experts from AECOM would explore the impact of a trio of major projects on a single city. In common with every metropolis, London has run-down districts and infrastructure in need of upgrading. The lectures propose to cover three of the biggest challenges: regenerating run-down areas; reducing congestion and transporting people more efficiently; and improving water and wastewater systems. Each project contributes to a collective public aim - to realise the potential of a growing city, and ensure its healthy, sustainable and competitive future. Lecture 1: Into the lecture series and The London 2012 Olympic Games Most cities share a group of common complex challenges – growing populations, ageing infrastructure, and mitigating the effects of climate change. These require similar responses to find the most appropriate solutions to make sure that all urban dwellers can have the basics of food, warmth, clean water and shelter. In addition, they must have the ...
Model of Cloud Computing Realisation on the Base of Infrastructure IaaS
Directory of Open Access Journals (Sweden)
Peter Peniak
2016-01-01
Full Text Available The paper deals with the problems of cloud computing applied for industrial applicationson the ground of practical experiences in certain manufacturing corporation. The main part of paperis orientated to proposal of the numerical model on the base of infrastructure as a service (IaaS and its mathematical description. In addition the model has been extended to include the requirements of mission critical systems with real time behaviour and fail-safe features. The models were realised via virtualisation software Hypervisor which creates a group of available virtual resources through physical infrastructure, which can be offered to customers. Proposal solution enables to create a proper sizeof cloud infrastructure for hardware provisioning according to customer requirements.
Realising the dream of becoming a nurse: Underrepresented BSc nursing students experiences.
O'Brien, Brid; Graham, Margaret M; O'Sullivan, Deirdre
2017-07-01
This paper describes the experiences of underrepresented BSc nursing students in realising the dream of becoming a nurse in one university. In the past ten years, pre-registration nurse education has become established within higher education in Ireland. This development includes promoting access and inclusion of students from traditionally underrepresented groups in higher education. A third of nursing students currently access places on programmes through routes specifically designed for underrepresented groups. A qualitative descriptive study design provided an opportunity for student voices to be heard. Ethical approval was sought and granted. Eleven students were interviewed nearing completion of a four year BSc Nursing programme. Data analysis followed a thematic approach, in generating themes. Three themes emerged from the data: taking the first steps; finding a way and getting through. Findings highlight participants' challenges in balancing study, clinical practice and family life in achieving and realising their dream of becoming a nurse. This study illustrates the nature and complexities of participants' experiences throughout the BSc Nursing programmes towards becoming university graduates, eligible for registration as a nurse. Students from underrepresented groups bring rich and diverse life experiences in preparation for and becoming caring practitioners. It highlights the individuality within participants' experiences and draws attention to the value of personalised support for students. An opportunity to encourage the development of emotional intelligence needs to be fostered within nurse education programmes. Creating positive learning environments is critical to supporting student understanding of compassionate patient centred care. Findings have relevance for global curriculum design and structures to support individual student centred engagement. Further research is required to consider how best to support students from underrepresented groups
Xu, Huan; Mannor, Shie
2008-01-01
Lasso, or $\\ell^1$ regularized least squares, has been explored extensively for its remarkable sparsity properties. It is shown in this paper that the solution to Lasso, in addition to its sparsity, has robustness properties: it is the solution to a robust optimization problem. This has two important consequences. First, robustness provides a connection of the regularizer to a physical property, namely, protection from noise. This allows a principled selection of the regularizer, and in particular, generalizations of Lasso that also yield convex optimization problems are obtained by considering different uncertainty sets. Secondly, robustness can itself be used as an avenue to exploring different properties of the solution. In particular, it is shown that robustness of the solution explains why the solution is sparse. The analysis as well as the specific results obtained differ from standard sparsity results, providing different geometric intuition. Furthermore, it is shown that the robust optimization formul...
Bose, Prosenjit; Morin, Pat; Smid, Michiel
2012-01-01
Highly connected and yet sparse graphs (such as expanders or graphs of high treewidth) are fundamental, widely applicable and extensively studied combinatorial objects. We initiate the study of such highly connected graphs that are, in addition, geometric spanners. We define a property of spanners called robustness. Informally, when one removes a few vertices from a robust spanner, this harms only a small number of other vertices. We show that robust spanners must have a superlinear number of edges, even in one dimension. On the positive side, we give constructions, for any dimension, of robust spanners with a near-linear number of edges.
Robustness of Structural Systems
DEFF Research Database (Denmark)
Canisius, T.D.G.; Sørensen, John Dalsgaard; Baker, J.W.
2007-01-01
The importance of robustness as a property of structural systems has been recognised following several structural failures, such as that at Ronan Point in 1968,where the consequenceswere deemed unacceptable relative to the initiating damage. A variety of research efforts in the past decades have...... systems. Guidance is provided regarding the assessment of robustness in a framework that considers potential hazards to the system, vulnerability of system components, and failure consequences. Several proposed methods for quantifying robustness are reviewed, and guidelines for robust design...
ROBUST CONTROL OF OSCILLATIONS IN AGRICULTURAL TRACTORS
DEFF Research Database (Denmark)
Andersen, T. O.; Hansen, M. R.; Conrad, Finn
2003-01-01
This paper deals with research results on investigations of robust control of oscillations in off-road vechicles, and relates to analyses and control of the oscillations occurring in many off road vehicles, which are designed without any suspension. Without suspension, the tire is the only elastic...... element acting between the vehicle and the ground but the suspension and damping properties of the tires cannotmeet the demands for fast, safe and comfortable road transportation. In this paper, the mentioned phenomenon was undertaken for investigation with special focus on robust oscillations...
Mechanisms for Robust Cognition
Walsh, Matthew M.; Gluck, Kevin A.
2015-01-01
To function well in an unpredictable environment using unreliable components, a system must have a high degree of robustness. Robustness is fundamental to biological systems and is an objective in the design of engineered systems such as airplane engines and buildings. Cognitive systems, like biological and engineered systems, exist within…
Mechanisms for Robust Cognition
Walsh, Matthew M.; Gluck, Kevin A.
2015-01-01
To function well in an unpredictable environment using unreliable components, a system must have a high degree of robustness. Robustness is fundamental to biological systems and is an objective in the design of engineered systems such as airplane engines and buildings. Cognitive systems, like biological and engineered systems, exist within…
Wang, H.
2009-01-01
Our society depends more strongly than ever on large networks such as transportation networks, the Internet and power grids. Engineers are confronted with fundamental questions such as “how to evaluate the robustness of networks for a given service?”, “how to design a robust network?”, because netwo
Lahtero, Tapio Juhani; Kuusilehto-Awale, Lea
2013-01-01
This article introduces a quantitative research into how the leadership team members of 49 basic education schools in the city of Vantaa, Finland, experienced the realisation of strategic leadership in their leadership teams' work. The data were collected by a survey of 24 statements, rated on a five-point Likert scale, and analysed with the…
Lahtero, Tapio Juhani; Kuusilehto-Awale, Lea
2013-01-01
This article introduces a quantitative research into how the leadership team members of 49 basic education schools in the city of Vantaa, Finland, experienced the realisation of strategic leadership in their leadership teams' work. The data were collected by a survey of 24 statements, rated on a five-point Likert scale, and analysed with the…
Soriano, Encarnacion; Franco, Clemente; Sleeter, Christine
2011-01-01
This study analysed the effects a values education programme can have on the feelings of self-realisation, self-concept and self-esteem of Romany adolescents in southern Spain. To do this, an experimental group received a values education intervention but a control group did not. The intervention programme was adapted to the Romany culture. The…
Soriano, Encarnacion; Franco, Clemente; Sleeter, Christine
2011-01-01
This study analysed the effects a values education programme can have on the feelings of self-realisation, self-concept and self-esteem of Romany adolescents in southern Spain. To do this, an experimental group received a values education intervention but a control group did not. The intervention programme was adapted to the Romany culture. The…
Realisation d'un detecteur de radioactivite pour un systeme microfluidique
Girard Baril, Frederique
Pour etablir le comportement pharmacocinetique de nouveaux radiotraceurs en imagerie moleculaire, il est necessaire d'approfondir l'analyse realisee a partir d'une image par l'ajout d'une mesure dynamique de la radioactivite dans le sang. L'Universite de Sherbrooke developpe presentement une plateforme microfluidique d'echantillonnage et d'analyse permettant la mesure de la radioactivite du plasma en temps reel. L'objectif du present projet de maitrise etait de realiser le composant optoelectronique responsable de la detection des positrons et de l'integrer a la puce microfluidique. L'option retenue a ete l'utilisation de photodiodes PIN en silicium. Un procede de fabrication, ainsi qu'une serie de photomasques ont ete developpes afin de produire une premiere iteration de prototypes. Les detecteurs ont ete concus de maniere a optimiser leur sensibilite en fonction du type de rayonnement a detecter. En effet, la region de detection doit etre suffisamment epaisse et sensible pour absorber le maximum de particules energetiques. Egalement, il est essentiel de minimiser le courant de fuite en noirceur afin d'obtenir un photocourant directement proportionnel a l'energie des radiations incidentes. Les caracteristiques electriques obtenues avec les premiers detecteurs ont ete demontrees proches des performances de detecteurs commerciaux similaires. De plus, il a ete possible d'integrer un canal microfluidique au substrat contenant les photodiodes et d'en realiser l'encapsulation sans alterer les performances electriques initiales des detecteurs. Une courbe de l'activite radioactive du 18F a ete mesuree, celle-ci se comparant a l'activite theorique associee a ce radioisotope communement utilise en TEP. Enfin, un spectre en energie des emissions radiatives du 18F a ete mesure et compare aux performances de systemes utilisant des photodiodes commerciales. Il a ete demontre que le prototype offrait un rapport signal sur bruit similaire aux systemes bases sur des photodiodes
DEFF Research Database (Denmark)
Faber, M.H.; Vrouwenvelder, A.C.W.M.; Sørensen, John Dalsgaard
2011-01-01
In 2005, the Joint Committee on Structural Safety (JCSS) together with Working Commission (WC) 1 of the International Association of Bridge and Structural Engineering (IABSE) organized a workshop on robustness of structures. Two important decisions resulted from this workshop, namely the developm......In 2005, the Joint Committee on Structural Safety (JCSS) together with Working Commission (WC) 1 of the International Association of Bridge and Structural Engineering (IABSE) organized a workshop on robustness of structures. Two important decisions resulted from this workshop, namely...... the development of a joint European project on structural robustness under the COST (European Cooperation in Science and Technology) programme and the decision to develop a more elaborate document on structural robustness in collaboration between experts from the JCSS and the IABSE. Accordingly, a project titled...... ‘COST TU0601: Robustness of Structures’ was initiated in February 2007, aiming to provide a platform for exchanging and promoting research in the area of structural robustness and to provide a basic framework, together with methods, strategies and guidelines enhancing robustness of structures...
An Advanced Robust AVR-PSS Based H2 and H∞ Frequency Approachs Simulated Under a Realized GUI
Directory of Open Access Journals (Sweden)
KABI Wahiba
2015-06-01
Full Text Available This article present a comparative study between two advanced robust frequency control strategies and their implementation using our realised Graphical User Interface ‘GUI’ under MATLAB software: the first method based on loop-shaping H∞ optimization technique and the second on robust H2 control method (LQG controller associated with KALMAN filter, and applied on automatic excitation control of synchronous generators, to improve transient stability and robustness of a single machine- infinite bus (SMIB system operating in different several conditions. The computer simulation results (static and dynamic stability, with test of robustness against machine parameters uncertainty (electric and mechanic, have proved that good dynamic performances, showing a stable system responses almost insensitive to large parameters variations, and more robustness using robust H∞ controller in comparison with H2 approach by exploiting our developed GUI interface in this work.
Robust and accurate detection algorithm for multimode polymer optical FBG sensor system
DEFF Research Database (Denmark)
Ganziy, Denis; Jespersen, O.; Rose, B.
2015-01-01
We propose a novel dynamic gate algorithm (DGA) for robust and fast peak detection. The algorithm uses a threshold determined detection window and center of gravity algorithm with bias compensation. Our experiment demonstrates that the DGA method is fast and robust with better stability...
MULTIDISCIPLINARY ROBUST OPTIMIZATION DESIGN
Institute of Scientific and Technical Information of China (English)
Chen Jianjiang; Xiao Renbin; Zhong Yifang; Dou Gang
2005-01-01
Because uncertainty factors inevitably exist under multidisciplinary design environment, a hierarchical multidisciplinary robust optimization design based on response surface is proposed. The method constructs optimization model of subsystem level and system level to coordinate the coupling among subsystems, and also the response surface based on the artificial neural network is introduced to provide information for system level optimization tool to maintain the independence of subsystems,i.e. to realize multidisciplinary parallel design. The application case of electrical packaging demonstrates that reasonable robust optimum solution can be yielded and it is a potential and efficient multidisciplinary robust optimization approach.
Robustness Beamforming Algorithms
Directory of Open Access Journals (Sweden)
Sajad Dehghani
2014-04-01
Full Text Available Adaptive beamforming methods are known to degrade in the presence of steering vector and covariance matrix uncertinity. In this paper, a new approach is presented to robust adaptive minimum variance distortionless response beamforming make robust against both uncertainties in steering vector and covariance matrix. This method minimize a optimization problem that contains a quadratic objective function and a quadratic constraint. The optimization problem is nonconvex but is converted to a convex optimization problem in this paper. It is solved by the interior-point method and optimum weight vector to robust beamforming is achieved.
Robustness Beamforming Algorithms
Directory of Open Access Journals (Sweden)
Sajad Dehghani
2014-09-01
Full Text Available Adaptive beamforming methods are known to degrade in the presence of steering vector and covariance matrix uncertinity. In this paper, a new approach is presented to robust adaptive minimum variance distortionless response beamforming make robust against both uncertainties in steering vector and covariance matrix. This method minimize a optimization problem that contains a quadratic objective function and a quadratic constraint. The optimization problem is nonconvex but is converted to a convex optimization problem in this paper. It is solved by the interior-point method and optimum weight vector to robust beamforming is achieved.
Ottosson, Hanna
2011-01-01
The essay discusses the world of Narnia from a psychological point of view. It argues that for Lucy, visiting Narnia takes the form of a psychological journey that represents the realisation of her repressed desires. It is through this realisation that Lucy develops as a character.
Towards Realising Secure and Efficient Image and Video Processing Applications on Quantum Computers
Directory of Open Access Journals (Sweden)
Abdullah M. Iliyasu
2013-07-01
Full Text Available Exploiting the promise of security and efficiency that quantum computing offers, the basic foundations leading to commercial applications for quantum image processing are proposed. Two mathematical frameworks and algorithms to accomplish the watermarking of quantum images, authentication of ownership of already watermarked images and recovery of their unmarked versions on quantum computers are proposed. Encoding the images as 2n-sized normalised Flexible Representation of Quantum Images (FRQI states, with n-qubits and 1-qubit dedicated to capturing the respective information about the colour and position of every pixel in the image respectively, the proposed algorithms utilise the flexibility inherent to the FRQI representation, in order to confine the transformations on an image to any predetermined chromatic or spatial (or a combination of both content of the image as dictated by the watermark embedding, authentication or recovery circuits. Furthermore, by adopting an apt generalisation of the criteria required to realise physical quantum computing hardware, three standalone components that make up the framework to prepare, manipulate and recover the various contents required to represent and produce movies on quantum computers are also proposed. Each of the algorithms and the mathematical foundations for their execution were simulated using classical (i.e., conventional or non-quantum computing resources, and their results were analysed alongside other longstanding classical computing equivalents. The work presented here, combined together with the extensions suggested, provide the basic foundations towards effectuating secure and efficient classical-like image and video processing applications on the quantum-computing framework.
Realisation et Applications D'un Laser a Fibre a L'erbium Monofrequence
Larose, Robert
L'incorporation d'ions de terres rares a l'interieur de la matrice de verre d'une fibre optique a permis l'emergence de composants amplificateurs tout-fibre. Le but de cette these consiste d'une part a analyser et a modeliser un tel dispositif et d'autre part, a fabriquer puis a caracteriser un amplificateur et un oscillateur a fibre. A l'aide d'une fibre fortement dopee a l'erbium fabriquee sur demande, on realise un laser a fibre syntonisable qui fonctionne en regime multimodes longitudinaux avec une largeur de raie de 1.5 GHz et egalement comme source monofrequencielle de largeur de raie de 70 kHz. Le laser sert ensuite a caracteriser un reseau de Bragg ecrit par photosensibilite dans une fibre optique. La technique de syntonisation permet aussi l'asservissement au fond d'une resonance de l'acetylene. Le laser garde alors la position centrale de la raie avec une erreur de moins de 1 MHz corrigeant ainsi les derives mecaniques de la cavite.
Engineering Dissipative Channels for Realising Schrödinger Cats in SQUIDs
Directory of Open Access Journals (Sweden)
Mark eEveritt
2014-10-01
Full Text Available We show that by engineering the interaction with the environment there exists a large class of systems that can evolve irreversibly to a cat state. To be precise we show that it is possible to engineer an irreversible process so that the steady state is close to a pure Schrödinger’s cat state by using double well systems and an environment comprising two-photon (or phonon absorbers. We also show that it should be possible to prolong the lifetime of a Schrödinger’s cat state exposed to the destructive effects of a conventional single-photon decohering environment. In addition to our general analysis we present a concrete circuit realisation of both system and environment that should be fabricatable with current technologies. Our protocol should make it easier to prepare and maintain Schrödinger cat states which would be useful in applications of quantum metrology and information processing as well as being of interest to those probing the quantum to classical transition.
Sukarno; Law, Cheryl Suwen; Santos, Abel
2017-06-08
We present the first realisation of linear variable bandpass filters in nanoporous anodic alumina (NAA-LVBPFs) photonic crystal structures. NAA gradient-index filters (NAA-GIFs) are produced by sinusoidal pulse anodisation and used as photonic crystal platforms to generate NAA-LVBPFs. The anodisation period of NAA-GIFs is modified from 650 to 850 s to systematically tune the characteristic photonic stopband of these photonic crystals across the UV-visible-NIR spectrum. Then, the nanoporous structure of NAA-GIFs is gradually widened along the surface under controlled conditions by wet chemical etching using a dip coating approach aiming to create NAA-LVBPFs with finely engineered optical properties. We demonstrate that the characteristic photonic stopband and the iridescent interferometric colour displayed by these photonic crystals can be tuned with precision across the surface of NAA-LVBPFs by adjusting the fabrication and etching conditions. Here, we envisage for the first time the combination of the anodisation period and etching conditions as a cost-competitive, facile, and versatile nanofabrication approach that enables the generation of a broad range of unique LVBPFs covering the spectral regions. These photonic crystal structures open new opportunities for multiple applications, including adaptive optics, hyperspectral imaging, fluorescence diagnostics, spectroscopy, and sensing.
Directory of Open Access Journals (Sweden)
Svetličič Marjan
2015-12-01
Full Text Available The main goal of the article is to establish how a small country, Slovenia, promoted its national interests when it held the Presidency of the Council of the EU, how this experience fits into the theory of small states and what lessons can be drawn for other small states. Based on a questionnaire administered to key Slovenian actors in the presidency, the analysis confirmed some of the theoretical expectations and revealed certain disparities. Our analysis confirms theoretical predictions that a member state can push through its national interests more easily during its presidency because it possesses certain powers that enable it to set the agenda, which is the most effective way of realising national interests. Especially true in the case of small state presidencies, advocating national interests can also be facilitated by a smaller range of priorities and a greater level of coincidence with the interests of other key actors. We revealed that, besides the country’s size, other factors also limited its ability to fulfil its national interests. In addition to a weak ability for coalition building and lobbying, the two main factors of constraint were the lack of soft knowledge among Slovenian officials and weak coordination among policy agents.
Advances in genetic engineering of the avian genome: "Realising the promise".
Doran, Timothy J; Cooper, Caitlin A; Jenkins, Kristie A; Tizard, Mark L V
2016-06-01
This review provides an historic perspective of the key steps from those reported at the 1st Transgenic Animal Research Conference in 1997 through to the very latest developments in avian transgenesis. Eighteen years later, on the occasion of the 10th conference in this series, we have seen breakthrough advances in the use of viral vectors and transposons to transform the germline via the direct manipulation of the chicken embryo, through to the establishment of PGC cultures allowing in vitro modification, expansion into populations to analyse the genetic modifications and then injection of these cells into embryos to create germline chimeras. We have now reached an unprecedented time in the history of chicken transgenic research where we have the technology to introduce precise, targeted modifications into the chicken genome, ranging from; new transgenes that provide improved phenotypes such as increased resilience to economically important diseases; the targeted disruption of immunoglobulin genes and replacement with human sequences to generate transgenic chickens that express "humanised" antibodies for biopharming; and the deletion of specific nucleotides to generate targeted gene knockout chickens for functional genomics. The impact of these advances is set to be realised through applications in chickens, and other bird species as models in scientific research, for novel biotechnology and to protect and improve agricultural productivity.
'Lived Islam' in India and Bangladesh: negotiating religion to realise reproductive aspirations.
Sahu, Biswamitra; Hutter, Inge
2012-01-01
This paper seeks to answer the question of how Muslim women interpret and negotiate religion in order to realise their reproductive aspirations. A close reading of lived experiences of 32 Muslim women from a varied educational background yields a wider perspective of the different interpretations of reproductive norms employed by adherents of the same religion (Islam), situated in two countries (India/Bangladesh) and group (majority/minority) contexts. Further, this comparative study yields a deeper understanding of agency that is employed by Muslim participants in each country. Muslim women - both in India and Bangladesh - are not passive followers of religious norms, but have agency to bring change in their own life and take an active role in planning their family, thereby transgressing religious norms in reproductive matters. Muslim women in India exercise their agency by adopting sterilisation - a method proscribed by Islam - without the knowledge of their significant others. Muslim women in Bangladesh use their agency by making a flexible interpretation of Islam in reproductive matters. A lesson learned from this comparative study is the need to remove barriers that prevent the adoption of contraceptives by Muslim minorities in India and to design family planning programmes that takes into account their religious needs.
Formation of the mechanism of realisation of the logistics strategy of river ports
Directory of Open Access Journals (Sweden)
Tymoshchuk Olena M.
2013-03-01
Full Text Available The article identifies the role of river ports in the logistical chain of supplies of the transportation system of Ukraine. It envisages to use the developed logistics strategy for creation of river logistics centres on the basis of river ports with a high level of logistical attractiveness, which would become organisers of cargo delivery at a certain stage of movement of goods and a connecting logistical link at the junction of transport elements of the system (systems of managing the process of transportation, information support, selection of optimal technological schemes of cargo treatment in the port and optimal interaction of adjacent types of transport, methods of management (organisational, economic, technical and technological, and legal, logistical principles and technologies, which would allow achievement of effective realisation of the logistics strategy of a river port. The article offers to create a separate commercial structure – information logistics centre, which would ensure information support of the logistical movement of goods and optimal managerial decision making.
Beyond Litigation: The Need for Creativity in Working to Realise Environmental Rights
Directory of Open Access Journals (Sweden)
Lisa Chamberlain
2017-06-01
Full Text Available Environmental harm is one of the biggest challenges facing communities living in poverty across the world. Unfortunately, in developing strategies to combat environmental harm, the lawyers that support such communities often tend to focus purely on litigation. Yet there are many reasons why litigation is not ideally suited to the environmental context. These reasons include the need for speed in order to avert irreversible harm quickly, the difficulty in quantifying and proving environmental harm using conventional legal tests, the very technical subject matter with which judges are often unfamiliar and the challenge of securing scientific experts. Fortunately litigation is not the only option, and a wealth of alternative strategies to realise environmental rights exist. Using the campaign to protect the Mapungubwe World Heritage Site in South Africa as a case study, this article will examine three such alternatives: namely the linkages between advocacy campaigns and company share price, community learning exchanges and an interesting model for collaboratively monitoring compliance by mining companies.
Oshri, Ilan; Kotlarsky, Julia
These days firms are, more than ever, pressed to demonstrate returns on their investment in outsourcing. While the initial returns can always be associated with one-off cost cutting, outsourcing arrangements are complex, often involving inter-related high-value activities, which makes the realisation of long-term benefits from outsourcing ever more challenging. Executives in client firms are no longer satisfied with the same level of service delivery through the outsourcing lifecycle. They seek to achieve business transformation and innovation in their present and future services, beyond satisfying service level agreements (SLAs). Clearly the business world is facing a new challenge: an outsourcing delivery system of high-value activities that demonstrates value over time and across business functions. However, despite such expectations, many client firms are in the dark when trying to measure and quantify the return on outsourcing investments: results of this research show that less than half of all CIOs and CFOs (43%) have attempted to calculate the financial impact of outsourcing to their bottom line, indicating that the financial benefits are difficult to quantify (51%).
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard
2008-01-01
. According to Danish design rules robustness shall be documented for all structures in high consequence class. The design procedure to document sufficient robustness consists of: 1) Review of loads and possible failure modes / scenarios and determination of acceptable collapse extent; 2) Review......This paper describes the background of the robustness requirements implemented in the Danish Code of Practice for Safety of Structures and in the Danish National Annex to the Eurocode 0, see (DS-INF 146, 2003), (DS 409, 2006), (EN 1990 DK NA, 2007) and (Sørensen and Christensen, 2006). More...... frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new structures essential...
Robustness - theoretical framework
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.
2010-01-01
More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....
Robust Nonstationary Regression
1993-01-01
This paper provides a robust statistical approach to nonstationary time series regression and inference. Fully modified extensions of traditional robust statistical procedures are developed which allow for endogeneities in the nonstationary regressors and serial dependence in the shocks that drive the regressors and the errors that appear in the equation being estimated. The suggested estimators involve semiparametric corrections to accommodate these possibilities and they belong to the same ...
Robustness - theoretical framework
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.
2010-01-01
More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....
Qualitative Robustness in Estimation
Directory of Open Access Journals (Sweden)
Mohammed Nasser
2012-07-01
Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman","serif";} Qualitative robustness, influence function, and breakdown point are three main concepts to judge an estimator from the viewpoint of robust estimation. It is important as well as interesting to study relation among them. This article attempts to present the concept of qualitative robustness as forwarded by first proponents and its later development. It illustrates intricacies of qualitative robustness and its relation with consistency, and also tries to remove commonly believed misunderstandings about relation between influence function and qualitative robustness citing some examples from literature and providing a new counter-example. At the end it places a useful finite and a simulated version of qualitative robustness index (QRI. In order to assess the performance of the proposed measures, we have compared fifteen estimators of correlation coefficient using simulated as well as real data sets.
Directory of Open Access Journals (Sweden)
Jing Li
2014-10-01
Full Text Available The highly efficient and robust stitching of aerial video captured by unmanned aerial vehicles (UAVs is a challenging problem in the field of robot vision. Existing commercial image stitching systems have seen success with offline stitching tasks, but they cannot guarantee high-speed performance when dealing with online aerial video sequences.In this paper, we present a novel system which has an unique ability to stitch high-frame rate aerial video at a speed of 150 frames per second (FPS. In addition, rather than using a high-speed vision platform such as FPGA or CUDA, our system is running on a normal personal computer. To achieve this, after the careful comparison of the existing invariant features, we choose the FAST corner and binary descriptor for efficient feature extraction and representation, and present a spatial and temporal coherent filter to fuse the UAV motion information into the feature matching. The proposed filter can remove the majority of feature correspondence outliers and significantly increase the speed of robust feature matching by up to 20 times. To achieve a balance between robustness and efficiency, a dynamic key frame-based stitching framework is used to reduce the accumulation errors.Extensive experiments on challenging UAV datasets demonstrate that our approach can break through the speed limitation and generate an accurate stitching image for aerial video stitching tasks.
A Robust and Fast Synchronization Technique for Adverse Grid Conditions
DEFF Research Database (Denmark)
Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan Carlos
2017-01-01
All grid-connected power converters require a device/algorithm for the synchronization with the utility grid. Among different synchronization techniques that have been proposed in recent years, the phase-locked loop (PLL) is probably the most popular one. The PLL, however, in its standard structure......, has a limited filtering capability. A simple yet effective idea to deal with this problem is including additional filters in the PLL structure. In this paper, an adaptive filtering technique for including into the PLL structure is suggested. A systematic design approach for tuning the PLL control...... parameters is then presented. The effectiveness of the proposed PLL is finally verified through a comparative performance analysis with the state-of-the-art PLLs....
Fast and robust object detection using asymmetric totally corrective boosting.
Wang, Peng; Shen, Chunhua; Barnes, Nick; Zheng, Hong
2012-01-01
Boosting-based object detection has received significant attention recently. In this paper, we propose totally corrective asymmetric boosting algorithms for real-time object detection. Our algorithms differ from Viola and Jones' detection framework in two ways. Firstly, our boosting algorithms explicitly optimize asymmetric loss of objectives, while AdaBoost used by Viola and Jones optimizes a symmetric loss. Secondly, by carefully deriving the Lagrange duals of the optimization problems, we design more efficient boosting in that the coefficients of the selected weak classifiers are updated in a totally corrective fashion, in contrast to the stagewise optimization commonly used by most boosting algorithms. Column generation is employed to solve the proposed optimization problems. Unlike conventional boosting, the proposed boosting algorithms are able to de-select those irrelevant weak classifiers in the ensemble while training a classification cascade. This results in improved detection performance as well as fewer weak classifiers in the learned strong classifier. Compared with AsymBoost of Viola and Jones, our proposed asymmetric boosting is nonheuristic and the training procedure is much simpler. Experiments on face and pedestrian detection demonstrate that our methods have superior detection performance than some of the state-of-the-art object detectors.
Improvement in Fast Particle Track Reconstruction with Robust Statistics
Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H -P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; Day, M; De Clercq, C; De Ridder, S; Desiati, P; de Vries, K D; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Ismail, A Haj; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kläs, J; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Macías, O; Madsen, J; Maggi, G; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Omairat, A; O'Murchadha, A; Paul, L; Pepper, J A; Heros, C Pérez de los; Pfendner, C; Pieloth, D; Pinat, E; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Shanidze, R; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stanisha, N A; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Unger, E; Usner, M; Vallecorsa, S; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M
2013-01-01
The IceCube project has transformed one cubic kilometer of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This manuscript describes work on two problems: (1) the track reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detectors early reconstruction with dat...
Application of Fast and Robust Equalization in Communication Technology
Institute of Scientific and Technical Information of China (English)
Ye Hua(叶桦); Zhou Wanlei; Ye Lin; Lanham Elicia; Raitman Ruth
2003-01-01
In this paper, the authors explore the potential of several popular equalization techniques while overcoming their disadvantages. First, extensive literature survey on equalization is conducted. The focus is on popular linear equalization algorithms such as the conventional least-mean-square (LMS ) algorithm, the recursive least-squares ( RLS ) algorithm, the filtered-X LMS algorithm and their development. To overcome the slow convergence problem while keeping the simplicity of the LMS based algorithms, an H2 optimal initialization is proposed.
A fast and robust hepatocyte quantification algorithm including vein processing
Directory of Open Access Journals (Sweden)
Homeyer André
2010-03-01
Full Text Available Abstract Background Quantification of different types of cells is often needed for analysis of histological images. In our project, we compute the relative number of proliferating hepatocytes for the evaluation of the regeneration process after partial hepatectomy in normal rat livers. Results Our presented automatic approach for hepatocyte (HC quantification is suitable for the analysis of an entire digitized histological section given in form of a series of images. It is the main part of an automatic hepatocyte quantification tool that allows for the computation of the ratio between the number of proliferating HC-nuclei and the total number of all HC-nuclei for a series of images in one processing run. The processing pipeline allows us to obtain desired and valuable results for a wide range of images with different properties without additional parameter adjustment. Comparing the obtained segmentation results with a manually retrieved segmentation mask which is considered to be the ground truth, we achieve results with sensitivity above 90% and false positive fraction below 15%. Conclusions The proposed automatic procedure gives results with high sensitivity and low false positive fraction and can be applied to process entire stained sections.
Robust Leader Election in a Fast-Changing World
Directory of Open Access Journals (Sweden)
John Augustine
2013-10-01
Full Text Available We consider the problem of electing a leader among nodes in a highly dynamic network where the adversary has unbounded capacity to insert and remove nodes (including the leader from the network and change connectivity at will. We present a randomized Las Vegas algorithm that (reelects a leader in O(Dlog n rounds with high probability, where D is a bound on the dynamic diameter of the network and n is the maximum number of nodes in the network at any point in time. We assume a model of broadcast-based communication where a node can send only 1 message of O(log n bits per round and is not aware of the receivers in advance. Thus, our results also apply to mobile wireless ad-hoc networks, improving over the optimal (for deterministic algorithms O(Dn solution presented at FOMC 2011. We show that our algorithm is optimal by proving that any randomized Las Vegas algorithm takes at least Ω(Dlog n rounds to elect a leader with high probability, which shows that our algorithm yields the best possible (up to constants termination time.
Directory of Open Access Journals (Sweden)
Samantha eDisbray
2016-02-01
Full Text Available The development of narrative skill has been investigated extensively in a wide range of languages, cross-linguistically and in multilingual settings (Berman & Slobin, 1994b; Hickmann, 2004; Severing & Verhoeven 2001, Strömqvist & Verhoeven, 2004. The present study investigates the development of reference realisation in narrative among Indigenous children in a remote urban township in Central Australia. The children, aged between 5 and 14 years, are speakers of a contact language, Wumpurrarni English. Language development is rarely investigated among speakers of minority languages, whose language development is often appraised in the majority language, with little attention to language performance in the speaker’s home variety. The present study addresses this gap through a fine-grained qualitative analysis of the development of reference in narrative, drawing on a complex stimulus and a model of discourse strategy. The results show a a developmental trajectory similar to that found in other languages, with children aged eight and under producing simpler and less globally organised narratives than older speaker groups, and b vulnerability to the changing demands of the stimulus among these younger speakers. In addition, a subset of narrations were produced in ‘school variety’, a style more like Standard Australian English, and the results for this set showed that the narrative content and global organisation of the productions by ten- and twelve–year-olds was more similar to the productions of younger children, than like-aged speakers narrating in their home variety. Analysis of speaker responses to two factors of complexity, the stimulus and code choice, illuminated mechanisms for discourse production and development, and suggest that constructing discourse requires co-ordination of an underlying schema and on-line construction of a particular story through the deployment of linguistic devices in a particular narrative context, and
Realising new health technologies: problems of regulating human stem cells in the USA.
Warren-Jones, Amanda
2012-01-01
Stem cell technology holds the promise of radically changing medicine through the provision of better disease models; the creation of tissue, cells, and organs for therapeutic uses; and the increased personalisation of healthcare. However, the degree to which any of these developments can be realised in the USA rests upon how effective the regulatory environment is in nurturing the technology to market. This article assesses the regulation in terms of its ability to minimise factors which erode the public interest in developing medical innovations (abuse) and promoting them to the market. This requires an overarching review of patent law (and how it fits with anti-trust and contract law); as well as the general regulation of innovation through ethical review, clinical trials, market authorisation, post-market oversight; government lead regulation of stem cells; and finally incorporating the impact of self-regulation by industry. From this assessment, it becomes possible to appreciate that the optimal system of regulation is reliant upon the gentle tweaking of many factors, rather than the wholesale revision of only a few. It also becomes possible to identify that individual tools of regulation have varying impacts. For example, the patent system may be the most open to abuse by individual companies, but as a regulatory framework it has the most mechanisms for dealing with such abuses. However, the biggest impact upon curtailing abuse derives from the self-regulation of the industry. Conversely, government led regulation is open to abuse from political agendas, but it has the greatest capacity to nurture innovation productively.
Realising skilled companionship in nursing: a utopian idea or difficult challenge?
Dierckx de Casterlé, Bernadette
2015-11-01
The question being considered in this discussion article is whether nurses' practice can be usefully characterised in terms of skilled companionship. A nurse's role might be characterised as one of a 'skilled companion,' a concept that brings together the scientific and moral basis of nursing practice. It is this focus on integrating both 'skill' and 'companionship' characteristics of nurses' practice that largely determines their effectiveness as care providers and their specific contribution to health care outcomes. Discursive article that invites readers to explore and arrive at a more comprehensive understanding of nurses' daily practice, one from an ethical perspective that is based on empirical data from the study of patients' caring experiences, nurses' caring experiences and nurses' ethical practice in daily care. Research in this era of health care highlights an important dilemma that the nursing profession is confronted with daily: realising nurses' role as a skilled companion in an environment where this concept of nursing care is discouraged, or even thwarted. Although the ethical dimension is explicitly and universally recognised as a core dimension of nursing care, research clearly highlights nurses' difficulties in translating this element into daily practice. Most disturbing in these findings is that both patients and nurses feel compelled to reach a compromise to 'survive' in this often-chaotic caring environment. It appears today that nurses' intrinsic strengths and potential are largely underutilised in daily practice. More than ever, the nursing profession is challenged to reflect on the future position, aspirations and responsibilities of nurses, to make clear choices, and to act accordingly. Viewing and implementing the nurse's role as one of a skilled companion promise better health care delivery in a postmodern world. © 2015 John Wiley & Sons Ltd.
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Hansen, Peter Reinhard; Lunde, Asger
This paper shows how to use realised kernels to carry out efficient feasible inference on the ex-post variation of underlying equity prices in the presence of simple models of market frictions. The issue is subtle with only estimators which have symmetric weights delivering consistent estimators...... with mixed Gaussian limit theorems. The weights can be chosen to achieve the best possible rate of convergence and to have an asymptotic variance which is close to that of the maximum likelihood estimator in the parametric version of this problem. Realised kernels can also be selected to (i) be analysed...... using endogenously spaced data such as that in databases on transactions, (ii) allow for market frictions which are endogenous, (iii) allow for temporally dependent noise. The finite sample performance of our estimators is studied using simulation, while empirical work illustrates their use in practice....
Epistemically Robust Strategy Subsets
Directory of Open Access Journals (Sweden)
Geir B. Asheim
2016-11-01
Full Text Available We define a concept of epistemic robustness in the context of an epistemic model of a finite normal-form game where a player type corresponds to a belief over the profiles of opponent strategies and types. A Cartesian product X of pure-strategy subsets is epistemically robust if there is a Cartesian product Y of player type subsets with X as the associated set of best reply profiles such that the set Y i contains all player types that believe with sufficient probability that the others are of types in Y − i and play best replies. This robustness concept provides epistemic foundations for set-valued generalizations of strict Nash equilibrium, applicable also to games without strict Nash equilibria. We relate our concept to closedness under rational behavior and thus to strategic stability and to the best reply property and thus to rationalizability.
Sriboonchitta, Songsak; Huynh, Van-Nam
2017-01-01
This book presents recent research on robustness in econometrics. Robust data processing techniques – i.e., techniques that yield results minimally affected by outliers – and their applications to real-life economic and financial situations are the main focus of this book. The book also discusses applications of more traditional statistical techniques to econometric problems. Econometrics is a branch of economics that uses mathematical (especially statistical) methods to analyze economic systems, to forecast economic and financial dynamics, and to develop strategies for achieving desirable economic performance. In day-by-day data, we often encounter outliers that do not reflect the long-term economic trends, e.g., unexpected and abrupt fluctuations. As such, it is important to develop robust data processing techniques that can accommodate these fluctuations.
Robustness of Spatial Micronetworks
McAndrew, Thomas C; Bagrow, James P
2015-01-01
Power lines, roadways, pipelines and other physical infrastructure are critical to modern society. These structures may be viewed as spatial networks where geographic distances play a role in the functionality and construction cost of links. Traditionally, studies of network robustness have primarily considered the connectedness of large, random networks. Yet for spatial infrastructure physical distances must also play a role in network robustness. Understanding the robustness of small spatial networks is particularly important with the increasing interest in microgrids, small-area distributed power grids that are well suited to using renewable energy resources. We study the random failures of links in small networks where functionality depends on both spatial distance and topological connectedness. By introducing a percolation model where the failure of each link is proportional to its spatial length, we find that, when failures depend on spatial distances, networks are more fragile than expected. Accounting...
2013-01-01
This contributed volume collects research papers, presented at the CIRP Sponsored Conference Robust Manufacturing Control: Innovative and Interdisciplinary Approaches for Global Networks (RoMaC 2012, Jacobs University, Bremen, Germany, June 18th-20th 2012). These research papers present the latest developments and new ideas focusing on robust manufacturing control for global networks. Today, Global Production Networks (i.e. the nexus of interconnected material and information flows through which products and services are manufactured, assembled and distributed) are confronted with and expected to adapt to: sudden and unpredictable large-scale changes of important parameters which are occurring more and more frequently, event propagation in networks with high degree of interconnectivity which leads to unforeseen fluctuations, and non-equilibrium states which increasingly characterize daily business. These multi-scale changes deeply influence logistic target achievement and call for robust planning and control ...
Robustness - acceptance criteria
DEFF Research Database (Denmark)
Rizzuto, Enrico; Sørensen, John Dalsgaard; Kroon, Inger B.
2010-01-01
This factsheet describes the general framework on the bases of which acceptance criteria for requirements on the robustness of structures can be set. Such framework is based on the more general concept of risk-based assessment of engineering systems. The present factsheet is to be seen in conjunc......This factsheet describes the general framework on the bases of which acceptance criteria for requirements on the robustness of structures can be set. Such framework is based on the more general concept of risk-based assessment of engineering systems. The present factsheet is to be seen...... in conjunction with the one on the theoretical framework for robustness (Sørensen et al. 2009). In the present factsheet, the focus is on normative implications....
Energy Technology Data Exchange (ETDEWEB)
Leconte, A.
1994-07-01
The 16 channels charge encoder herein described equips the Phoswich scintillators which, associated with photomultiplier tubes, constitutes the first ring of the INDRA Multidetector. This 4 {pi} Multidetector, located at GANIL at Caen, is first presented. In this encoder, two integrations are made, offering a distinction between the fast component of the signal from the detector and the slow one (decreasing times: 2,4 ns and 320ns respectively). This measurement is performed by the integration of each component within an adjustable time-gate. Apart from the two integrations, the encoder realizes the detection of the impulsion with a constant fraction discriminator, the generation of the two gates and a test function. The use of surface mounted components together with the choice of the VXI interconnection standard, also presented in this report, allowed highly integrated electronics. The encoder uses the sliding scale principle. It also includes the electronics for some programmable adjustments, the remote visualisation of important signals and the logic for the conversion. (author). 22 refs.
Robust global motion estimation
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A global motion estimation method based on robust statistics is presented in this paper. By using tracked feature points instead of whole image pixels to estimate parameters the process speeds up. To further speed up the process and avoid numerical instability, an alterative description of the problem is given, and three types of solution to the problem are compared. By using a two step process, the robustness of the estimator is also improved. Automatic initial value selection is an advantage of this method. The proposed approach is illustrated by a set of examples, which shows good results with high speed.
Terzi, A.; Ockels, W.J.
2008-01-01
The Superbus was introduced as one of the option for the Zuiderzeelijn : a fast connection between Amsterdam and Groningen and resulted to be the best option, the others being three different types of high speed train and the magnetic levitation train. In order evaluate the feasibility of its implem
Institute of Scientific and Technical Information of China (English)
吴烈; 杨仕友; 李玉玲
2013-01-01
为提高电磁场逆问题鲁棒优化设计的计算效率,提出一种基于多项式混沌和进化算法相结合的快速鲁棒优化方法.在该方法中,通过将多项式混沌展开作为鲁棒性能参数的随机响应面模型,提高了期望函数的计算效率和计算精度.此外,为进一步提高算法的计算效率,文章又提出了期望适值赋值的新机制,以及概率可行性模型处理约束函数鲁棒性的方法；引入同时搜索全局最优解和鲁棒最优解的迭代循环机制.通过典型电磁场逆问题的鲁棒优化设计对本文算法进行了数值验证.数值分析结果证明了该文方法的可行性和先进性.%This paper explores the potential of polynomial chaos in robust design optimizations of inverse problems. To this end, a fast numerical methodology based on combinations of polynomial chaos expansion and evolutionary algorithm is proposed. In the proposed methodology, the polynomial chaos expansion is used as a stochastic response surface model for efficient computations of the expectancy metric of the objective function. Additional enhancements, such as the introduction of new methodology for expected fitness assignment and probability feasibility model, a novel driving mechanism to bias the next iterative cycles to search for both global and robust optimal solutions, are introduced. The numerical results on two case studies are reported to illustrate the feasibility and advantage of the present work.
Complexity, Robustness, and Performance
B. Visser (Bauke)
2002-01-01
textabstractThis paper analyses the relationship between organizational complexity ( the degree of detail of information necessary to correctly assign agents to positions), robustness (the relative loss of performance due to mis-allocated agents), and performance. More complex structures are not
Robustness via Diffractal Architectures
Moocarme, Matthew
2015-01-01
When plane waves diffract through fractal-patterned apertures, the resulting far-field profiles or diffractals also exhibit iterated, self-similar features. Here we show that this specific architecture enables robust signal processing and spatial multiplexing: arbitrary parts of a diffractal contain sufficient information to recreate the entire original sparse signal.
DEFF Research Database (Denmark)
Vrouwenvelder, T.; Sørensen, John Dalsgaard
2009-01-01
robustness is still an issue of controversy and poses difficulties in regard to interpretation as well as regulation. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages'. However, despite the importance...
Robustness Envelopes of Networks
Trajanovski, S.; Martín-Hernández, J.; Winterbach, W.; Van Mieghem, P.
2013-01-01
We study the robustness of networks under node removal, considering random node failure, as well as targeted node attacks based on network centrality measures. Whilst both of these have been studied in the literature, existing approaches tend to study random failure in terms of average-case behavior
Complexity, Robustness, and Performance
B. Visser (Bauke)
2002-01-01
textabstractThis paper analyses the relationship between organizational complexity ( the degree of detail of information necessary to correctly assign agents to positions), robustness (the relative loss of performance due to mis-allocated agents), and performance. More complex structures are not nec
Energy Technology Data Exchange (ETDEWEB)
Botter, F.; Molinari, Ph.; Dirian, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1964-07-01
type, de capacite totale environ 2 litres, il a ete realise un appareil preparatif, de faible volume mort, permettant de produire 1 litre de D{sub 2} pur a partir des melange 50 p.100 D{sub 2}, 50 p.100 H{sub 2} en 12 minutes environ. Sur le plan theorique, en premiere approximation, nous assimilions la chromatographie a un fractionnement contre courant en negligeant resistance superficielle a l'echange ainsi que diffusions longitudinale et laterale. On etablit graphiquement ou par calcul, le nombre de plateaux theoriques necessires a un certain enrichissement de la phase gazeuse ce qui permet de comparer l'efficacite de colonnes qui different par leur masse palladiee. DIFFUSION THERMIQUE: Afin d'assurer une separation des isotopes de l'hydrogene, on a realise une installation de diffusion thermique construite en acier inoxydable et entierement telecommandee. La cascade de separation se compose de deux couples identiques de colonnes a fil central chaud. Chaque couple peut travailler isolement ou etre relie par thermosyphon. La temperature du fil chaud est de l'ordre de 1000 deg C entretenue par courant redresse. Avec cette installation, des echantillons d'hydrogene a la teneur isotopique en deuterium inferieure a 0,5 ppm. ont ete obtenus a partir d'un gaz initial a 32 ppm. Il a ainsi ete possible de preparer du tritium a la teneur de 99,3 p. 100 a partir d'un gaz d'une teneur initale de 6 p. 100. Pour la separation quantitative du Xenon enrichi cinq fois en {sup 124}Xe par thermodiffusion on a construit deux cascades identiques de 5 colonnes fonctionnant en parallele, reliees par thermosyphon ou par tube capillaire lie a un oscillateur thermique de gaz. Le fil central en tungstene fonctionne a 1200 deg C. Les colonnes sont groupees a la facon d'un faisceau tubulaire d'un echangeur de chaleur dans une virole de 30 cm de diametre ou circule l'eau de refroidissement. Des etudes sont en cours pour augmenter le
Syngas from biomass. Problems and solutions en route to a technical realisation
Energy Technology Data Exchange (ETDEWEB)
Dinjus, E.; Dahmen, N.; Henrich, E. [Forschungszentrum Karlsruhe (Germany). ITC-CPV
2006-07-01
A thermochemical two-step process called bioliq {sup registered} for the conversion of biomass in tailored synfuels and organic chemicals via the production of syngas as a versatile intermediate is being developed at the Karlsruhe research centre. The development work has been focused on syngas generation from liquefied biomass in a pressurized entrained flow gasifier. The sequential process steps have been successfully investigated in the laboratory and on the pilot plant scale. Fast pyrolysis has been chosen as a simple and cheap liquefaction step for lignocellulosic biomass. The LURGI twin-screw mixer reactor known from other technical applications was found to be well suited also for biomass fast pyrolysis. Pumpable, homogenous slurries of pyrolysis liquids with high loadings of pyrolysis char powder have been prepared with colloid mixers for subsequent gasification. Efficient and smooth slurry gasification to a tar-free, low methane syngas has been obtained with a number of different slurries in four testing campaigns in the 3 - 5 MWth entrained flow pilot gasifier of FUTURE ENERGY, Freiberg, at 26 bar. The continuing work will be supplemented by syngas cleaning and synthesis steps. A complete process line with around 2 MWth capacity from fast pyrolysis to synthesis with an 80 bar gasifier is under design, the pyrolysis plant already under construction in co-operation with LURGI. (orig.)
Comparing dependent robust correlations.
Wilcox, Rand R
2016-11-01
Let r1 and r2 be two dependent estimates of Pearson's correlation. There is a substantial literature on testing H0 : ρ1 = ρ2 , the hypothesis that the population correlation coefficients are equal. However, it is well known that Pearson's correlation is not robust. Even a single outlier can have a substantial impact on Pearson's correlation, resulting in a misleading understanding about the strength of the association among the bulk of the points. A way of mitigating this concern is to use a correlation coefficient that guards against outliers, many of which have been proposed. But apparently there are no results on how to compare dependent robust correlation coefficients when there is heteroscedasicity. Extant results suggest that a basic percentile bootstrap will perform reasonably well. This paper reports simulation results indicating the extent to which this is true when using Spearman's rho, a Winsorized correlation or a skipped correlation.
Kutzner, Florian; Vogel, Tobias; Freytag, Peter; Fiedler, Klaus
2011-01-01
In the present research, we argue for the robustness of illusory correlations (ICs, Hamilton & Gifford, 1976) regarding two boundary conditions suggested in previous research. First, we argue that ICs are maintained under extended experience. Using simulations, we derive conflicting predictions. Whereas noise-based accounts predict ICs to be maintained (Fielder, 2000; Smith, 1991), a prominent account based on discrepancy-reducing feedback learning predicts ICs to disappear (Van Rooy et al., 2003). An experiment involving 320 observations with majority and minority members supports the claim that ICs are maintained. Second, we show that actively using the stereotype to make predictions that are met with reward and punishment does not eliminate the bias. In addition, participants' operant reactions afford a novel online measure of ICs. In sum, our findings highlight the robustness of ICs that can be explained as a result of unbiased but noisy learning.
1985-09-19
13.2 3.6. 14.0. 1.8. 11111.52 *.6 L 3 n1 i erated ~~~m nc. AFOSR-TR- 798 s AD-A 161 349 ROBUST ADAPTIVE CONTROL * FINAL REPORT PREPARED BY: R~ OBERT L... Centre Block Computes the Norm of the [1I] Solo, V., "Time Series Recursions and Stochastc Regressors. The Rematning Elemerts Imple- Approximation
Energy Technology Data Exchange (ETDEWEB)
Rider, William, E-mail: wjrider@sandia.gov [Sandia National Laboratories, Center for Computing Research, Albuquerque, NM 87185 (United States); Witkowski, Walt [Sandia National Laboratories, Verification and Validation, Uncertainty Quantification, Credibility Processes Department, Engineering Sciences Center, Albuquerque, NM 87185 (United States); Kamm, James R. [Los Alamos National Laboratory, Methods and Algorithms Group, Computational Physics Division, Los Alamos, NM 87545 (United States); Wildey, Tim [Sandia National Laboratories, Center for Computing Research, Albuquerque, NM 87185 (United States)
2016-02-15
We introduce a new methodology for inferring the accuracy of computational simulations through the practice of solution verification. We demonstrate this methodology on examples from computational heat transfer, fluid dynamics and radiation transport. Our methodology is suited to both well- and ill-behaved sequences of simulations. Our approach to the analysis of these sequences of simulations incorporates expert judgment into the process directly via a flexible optimization framework, and the application of robust statistics. The expert judgment is systematically applied as constraints to the analysis, and together with the robust statistics guards against over-emphasis on anomalous analysis results. We have named our methodology Robust Verification. Our methodology is based on utilizing multiple constrained optimization problems to solve the verification model in a manner that varies the analysis' underlying assumptions. Constraints applied in the analysis can include expert judgment regarding convergence rates (bounds and expectations) as well as bounding values for physical quantities (e.g., positivity of energy or density). This approach then produces a number of error models, which are then analyzed through robust statistical techniques (median instead of mean statistics). This provides self-contained, data and expert informed error estimation including uncertainties for both the solution itself and order of convergence. Our method produces high quality results for the well-behaved cases relatively consistent with existing practice. The methodology can also produce reliable results for ill-behaved circumstances predicated on appropriate expert judgment. We demonstrate the method and compare the results with standard approaches used for both code and solution verification on well-behaved and ill-behaved simulations.
Robust Self Tuning Controllers
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
1985-01-01
The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay....
Robustness of Interdependent Networks
Havlin, Shlomo
2011-03-01
In interdependent networks, when nodes in one network fail, they cause dependent nodes in other networks to also fail. This may happen recursively and can lead to a cascade of failures. In fact, a failure of a very small fraction of nodes in one network may lead to the complete fragmentation of a system of many interdependent networks. We will present a framework for understanding the robustness of interacting networks subject to such cascading failures and provide a basic analytic approach that may be useful in future studies. We present exact analytical solutions for the critical fraction of nodes that upon removal will lead to a failure cascade and to a complete fragmentation of two interdependent networks in a first order transition. Surprisingly, analyzing complex systems as a set of interdependent networks may alter a basic assumption that network theory has relied on: while for a single network a broader degree distribution of the network nodes results in the network being more robust to random failures, for interdependent networks, the broader the distribution is, the more vulnerable the networks become to random failure. We also show that reducing the coupling between the networks leads to a change from a first order percolation phase transition to a second order percolation transition at a critical point. These findings pose a significant challenge to the future design of robust networks that need to consider the unique properties of interdependent networks.
Directory of Open Access Journals (Sweden)
Marek Hicar
2004-01-01
Full Text Available The article is about a control design for complete structure of the crane: crab, bridge and crane uplift.The most important unknown parameters for simulations are burden weight and length of hanging rope. We will use robustcontrol for crab and bridge control to ensure adaptivity for burden weight and rope length. Robust control will be designed for current control of the crab and bridge, necessary is to know the range of unknown parameters. Whole robust will be splitto subintervals and after correct identification of unknown parameters the most suitable robust controllers will be chosen.The most important condition at the crab and bridge motion is avoiding from burden swinging in the final position. Crab and bridge drive is designed by asynchronous motor fed from frequency converter. We will use crane uplift with burden weightobserver in combination for uplift, crab and bridge drive with cooperation of their parameters: burden weight, rope length and crab and bridge position. Controllers are designed by state control method. We will use preferably a disturbance observerwhich will identify burden weight as a disturbance. The system will be working in both modes at empty hook as well asat maximum load: burden uplifting and dropping down.
ForBild: efficient robust image hashing
Steinebach, Martin; Liu, Huajian; Yannikos, York
2012-03-01
Forensic analysis of image sets today is most often done with the help of cryptographic hashes due to their efficiency, their integration in forensic tools and their excellent reliability in the domain of false detection alarms. A drawback of these hash methods is their fragility to any image processing operation. Even a simple re-compression with JPEG results in an image not detectable. A different approach is to apply image identification methods, allowing identifying illegal images by e.g. semantic models or facing detection algorithms. Their common drawback is a high computational complexity and significant false alarm rates. Robust hashing is a well-known approach sharing characteristics of both cryptographic hashes and image identification methods. It is fast, robust to common image processing and features low false alarm rates. To verify its usability in forensic evaluation, in this work we discuss and evaluate the behavior of an optimized block-based hash.
Robust Pseudo-Hierarchical Support Vector Clustering
DEFF Research Database (Denmark)
Hansen, Michael Sass; Sjöstrand, Karl; Olafsdóttir, Hildur
2007-01-01
Support vector clustering (SVC) has proven an efficient algorithm for clustering of noisy and high-dimensional data sets, with applications within many fields of research. An inherent problem, however, has been setting the parameters of the SVC algorithm. Using the recent emergence of a method...... for calculating the entire regularization path of the support vector domain description, we propose a fast method for robust pseudo-hierarchical support vector clustering (HSVC). The method is demonstrated to work well on generated data, as well as for detecting ischemic segments from multidimensional myocardial...
Robust laser frequency stabilization by serrodyne modulation
Kohlhaas, Ralf; Bernon, Simon; Bertoldi, Andrea; Landragin, Arnaud; Bouyer, Philippe
2011-01-01
We report the frequency stabilization of a distributed feedback erbium-doped fiber laser on an optical cavity by serrodyne frequency shifting. A correction bandwidth of 2.4 MHz and a dynamic range of 220 MHz are achieved, which leads to a strong robustness against large disturbances up to high frequencies. Serrodyne frequency shifting allows to use an electro-optical modulator as a fast external transducer with a correction range which exceeds the one of acousto-optical modulators by at least one order of magnitude.
Directory of Open Access Journals (Sweden)
D. V. Vereshikov
2014-01-01
Full Text Available In article results of researches are presented according to efficiency of application of adaptive algorithm of management by the maneuverable plane realised in a cross-section control path, on the basis of identification of some aerodynamic characteristics of the plane and the indignations caused by formation by an asymmetrical configuration of placing of external suspension. By modelling of movement of the plane during performance S - figurative maneuvers with use of a programmno-modelling complex and the flight stand substantial improvement of characteristics of controllability of the asymmetrical plane and, thus, increase of efficiency of its application is shown.
Theory of Fast Electron Transport for Fast Ignition
Robinson, A P L; Davies, J R; Gremillet, L; Honrubia, J J; Johzaki, T; Kingham, R J; Sherlock, M; Solodov, A A
2013-01-01
Fast Ignition Inertial Confinement Fusion is a variant of inertial fusion in which DT fuel is first compressed to high density and then ignited by a relativistic electron beam generated by a fast (< 20 ps) ultra-intense laser pulse, which is usually brought in to the dense plasma via the inclusion of a re-entrant cone. The transport of this beam from the cone apex into the dense fuel is a critical part of this scheme, as it can strongly influence the overall energetics. Here we review progress in the theory and numerical simulation of fast electron transport in the context of Fast Ignition. Important aspects of the basic plasma physics, descriptions of the numerical methods used, a review of ignition-scale simulations, and a survey of schemes for controlling the propagation of fast electrons are included. Considerable progress has taken place in this area, but the development of a robust, high-gain FI `point design' is still an ongoing challenge.
Robustness of Cantor diffractals.
Verma, Rupesh; Sharma, Manoj Kumar; Banerjee, Varsha; Senthilkumaran, Paramasivam
2013-04-08
Diffractals are electromagnetic waves diffracted by a fractal aperture. In an earlier paper, we reported an important property of Cantor diffractals, that of redundancy [R. Verma et. al., Opt. Express 20, 8250 (2012)]. In this paper, we report another important property, that of robustness. The question we address is: How much disorder in the Cantor grating can be accommodated by diffractals to continue to yield faithfully its fractal dimension and generator? This answer is of consequence in a number of physical problems involving fractal architecture.
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.
Robustness Metrics: Consolidating the multiple approaches to quantify Robustness
DEFF Research Database (Denmark)
Göhler, Simon Moritz; Eifler, Tobias; Howard, Thomas J.
2016-01-01
determined to be conceptually different from one another. The metrics were classified by their meaning and interpretation based on the types of information necessary to calculate the metrics. Four different classes were identified: 1) Sensitivity robustness metrics; 2) Size of feasible design space...... and to remove the ambiguities of the term robustness. By applying an exemplar metric from each class to a case study, the differences between the classes were further highlighted.These classes form the basis for the definition of four specific sub-definitions of robustness, namely the ‘robust concept’, ‘robust...
Adaptive Robust Variable Selection
Fan, Jianqing; Barut, Emre
2012-01-01
Heavy-tailed high-dimensional data are commonly encountered in various scientific fields and pose great challenges to modern statistical analysis. A natural procedure to address this problem is to use penalized least absolute deviation (LAD) method with weighted $L_1$-penalty, called weighted robust Lasso (WR-Lasso), in which weights are introduced to ameliorate the bias problem induced by the $L_1$-penalty. In the ultra-high dimensional setting, where the dimensionality can grow exponentially with the sample size, we investigate the model selection oracle property and establish the asymptotic normality of the WR-Lasso. We show that only mild conditions on the model error distribution are needed. Our theoretical results also reveal that adaptive choice of the weight vector is essential for the WR-Lasso to enjoy these nice asymptotic properties. To make the WR-Lasso practically feasible, we propose a two-step procedure, called adaptive robust Lasso (AR-Lasso), in which the weight vector in the second step is c...
Directory of Open Access Journals (Sweden)
Richard A. Shweder
2013-11-01
Full Text Available In this wide ranging interview, Professor Richard A. Shweder from the Department of Comparative Human Development at the University of Chicago, discusses whether it is or is not possible to be a robust cultural pluralist and a dedicated political liberal at the same time. In this discussion, Professor Shweder offers his insights - based on over 40 years of research - on issues related to the history and re-emergence of cultural psychology; moral anthropology and psychology; the experimental method in psychological investigation and its philosophical basis; contemporary and historical cultural collisions – most notably conflicting representations of female genital surgeries; cultural diversity and inequality; and the dissemination of ideas through open access publishing and Twitter. Professor Shweder ends by offering valuable advice to young researchers in the field of cultural psychology as well as a glimpse into the larger themes of his forthcoming book, which seeks to provide answers to the question of what forms of political liberalism are most compatible with robust cultural pluralism and which are not.
Directory of Open Access Journals (Sweden)
Chrizell Chürr
2015-12-01
Full Text Available Education has, since the beginning of time, been regarded as the formal process by which society conveys its accumulated knowledge, skills, customs and values from one generation to another. Today, education is a human right, and the right to education and specifically the right to (a basic education is acknowledged and emphasised worldwide. In South Africa the right to a basic education is entrenched in the Constitution of the Republic of South Africa, 1996 and is regarded as one of the most crucial constitutional rights, particularly because it promotes economic and social well-being. However, the South African school system is crippled by a myriad of unfavourable challenges, situations and circumstances which will be discussed throughout the article. Many of these challenges, situations and circumstances are frustrating and solutions have been sought diligently – many with success and many without success. The focus in this article falls on the questions of whether the current South African school system sufficiently realises the constitutional rights of learners and whether an alternative school system could lead to the increased fulfilment and realisation of South African children's rights (with a specific focus on the rights to a basic education, equality and dignity. The article therefore deals with the "acceptability" of the South African school system. A comparative analysis with Germany will be done and the German school system will be used as a valuable framework in order to propose an alternative school system for South Africa.
Benders, Titia
2013-12-01
Exaggeration of the vowel space in infant-directed speech (IDS) is well documented for English, but not consistently replicated in other languages or for other speech-sound contrasts. A second attested, but less discussed, pattern of change in IDS is an overall rise of the formant frequencies, which may reflect an affective speaking style. The present study investigates longitudinally how Dutch mothers change their corner vowels, voiceless fricatives, and pitch when speaking to their infant at 11 and 15 months of age. In comparison to adult-directed speech (ADS), Dutch IDS has a smaller vowel space, higher second and third formant frequencies in the vowels, and a higher spectral frequency in the fricatives. The formants of the vowels and spectral frequency of the fricatives are raised more strongly for infants at 11 than at 15 months, while the pitch is more extreme in IDS to 15-month olds. These results show that enhanced positive affect is the main factor influencing Dutch mothers' realisation of speech sounds in IDS, especially to younger infants. This study provides evidence that mothers' expression of emotion in IDS can influence the realisation of speech sounds, and that the loss or gain of speech clarity may be secondary effects of affect. Copyright © 2013 Elsevier Inc. All rights reserved.
2012-01-01
How Large-Scale Civil Engineering Projects Realise the Potential of a City (1/3), by Bill Hanway (Excecutive Director of Operations, AECOM Europe). Wednesday, June 6, 2012 from 11:00 to 12:00 (Europe/Zurich) at CERN ( 80-1-001 - Globe 1st Floor ) In this series of three special lectures, leading experts from AECOM would explore the impact of a trio of major projects on a single city. In common with every metropolis, London has run-down districts and infrastructure in need of upgrading. The lectures propose to cover three of the biggest challenges: regenerating run-down areas; reducing congestion and transporting people more efficiently; and improving water and wastewater systems. Each project contributes to a collective public aim - to realise the potential of a growing city, and ensure its healthy, sustainable and competitive future. Lecture 1: Into the lecture series and The London 2012 Olympic Games Most cities share a group of common complex challenges – growing populations, agei...
Ethernet susceptibility to electric fast transients
van Leersum, B.J.A.M.; Buesink, Frederik Johannes Karel; Bergsma, J.G.; Leferink, Frank Bernardus Johannes
2013-01-01
The effect of Electric Fast Transients (EFT) phenomena in an Ethernet interface set-up is investigated in order to get more insight in coupling and interference mechanisms, robustness and susceptibility levels of a typical Ethernet installation on board of a naval vessel. It is shown that already a
Robust level set method for computer vision
Si, Jia-rui; Li, Xiao-pei; Zhang, Hong-wei
2005-12-01
Level set method provides powerful numerical techniques for analyzing and solving interface evolution problems based on partial differential equations. It is particularly appropriate for image segmentation and other computer vision tasks. However, there exists noise in every image and the noise is the main obstacle to image segmentation. In level set method, the propagation fronts are apt to leak through the gaps at locations of missing or fuzzy boundaries that are caused by noise. The robust level set method proposed in this paper is based on the adaptive Gaussian filter. The fast marching method provides a fast implementation for level set method and the adaptive Gaussian filter can adapt itself to the local characteristics of an image by adjusting its variance. Thus, the different parts of an image can be smoothed in different way according to the degree of noisiness and the type of edges. Experiments results demonstrate that the adaptive Gaussian filter can greatly reduce the noise without distorting the image and made the level set methods more robust and accurate.
International Conference on Robust Statistics
Filzmoser, Peter; Gather, Ursula; Rousseeuw, Peter
2003-01-01
Aspects of Robust Statistics are important in many areas. Based on the International Conference on Robust Statistics 2001 (ICORS 2001) in Vorau, Austria, this volume discusses future directions of the discipline, bringing together leading scientists, experienced researchers and practitioners, as well as younger researchers. The papers cover a multitude of different aspects of Robust Statistics. For instance, the fundamental problem of data summary (weights of evidence) is considered and its robustness properties are studied. Further theoretical subjects include e.g.: robust methods for skewness, time series, longitudinal data, multivariate methods, and tests. Some papers deal with computational aspects and algorithms. Finally, the aspects of application and programming tools complete the volume.
Robust automated knowledge capture.
Energy Technology Data Exchange (ETDEWEB)
Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt
2011-10-01
This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.
Passion, Robustness and Perseverance
DEFF Research Database (Denmark)
Lim, Miguel Antonio; Lund, Rebecca
2016-01-01
Evaluation and merit in the measured university are increasingly based on taken-for-granted assumptions about the “ideal academic”. We suggest that the scholar now needs to show that she is passionate about her work and that she gains pleasure from pursuing her craft. We suggest that passion...... and pleasure achieve an exalted status as something compulsory. The scholar ought to feel passionate about her work and signal that she takes pleasure also in the difficult moments. Passion has become a signal of robustness and perseverance in a job market characterised by funding shortages, increased pressure...... to produce measurable output, and precariousness. For young academics in particular it is increasingly important to demonstrate the “right attitude”, “feelings”, and “personality traits” because they have yet to accumulate a record of past achievements that are used as the basis of merit. In hiring decisions...
Robust Optical Flow Estimation
Directory of Open Access Journals (Sweden)
Javier Sánchez Pérez
2013-10-01
Full Text Available n this work, we describe an implementation of the variational method proposed by Brox etal. in 2004, which yields accurate optical flows with low running times. It has several benefitswith respect to the method of Horn and Schunck: it is more robust to the presence of outliers,produces piecewise-smooth flow fields and can cope with constant brightness changes. Thismethod relies on the brightness and gradient constancy assumptions, using the information ofthe image intensities and the image gradients to find correspondences. It also generalizes theuse of continuous L1 functionals, which help mitigate the effect of outliers and create a TotalVariation (TV regularization. Additionally, it introduces a simple temporal regularizationscheme that enforces a continuous temporal coherence of the flow fields.
Validation of community robustness
Carissimo, Annamaria; Defeis, Italia
2016-01-01
The large amount of work on community detection and its applications leaves unaddressed one important question: the statistical validation of the results. In this paper we present a methodology able to clearly detect if the community structure found by some algorithms is statistically significant or is a result of chance, merely due to edge positions in the network. Given a community detection method and a network of interest, our proposal examines the stability of the partition recovered against random perturbations of the original graph structure. To address this issue, we specify a perturbation strategy and a null model to build a set of procedures based on a special measure of clustering distance, namely Variation of Information, using tools set up for functional data analysis. The procedures determine whether the obtained clustering departs significantly from the null model. This strongly supports the robustness against perturbation of the algorithm used to identify the community structure. We show the r...
Provably robust digital watermarking
Chen, Brian; Wornell, Gregory W.
1999-11-01
Copyright notification and enforcement, authentication, covert communication, and hybrid transmission are examples of emerging multimedia applications for digital watermarking methods, methods for embedding one signal (e.g., the digital watermark) within another 'host' signal to form a third, 'composite' signal. The embedding is designed to achieve efficient trade-offs among the three conflicting goals of maximizing information-embedding rate, minimizing distortion between the host signal and composite signal, and maximizing the robustness of the embedding. Quantization index modulation (QIM) methods are a class of watermarking methods that achieve provably good rate-distortion-robustness performance. Indeed, QIM methods exist that achieve performance within a few dB of capacity in the case of a (possibly colored) Gaussian host signal and an additive (possibly colored) Gaussian noise channel. Also, QIM methods can achieve capacity with a type of postprocessing called distortion compensation. This capacity is independent of host signal statistics, and thus, contrary to popular belief, the information-embedding capacity when the host signal is not available at the decoder is the same as the case when the host signal is available at the decoder. A low-complexity realization of QIM called dither modulation has previously been proven to be better than both linear methods of spread spectrum and nonlinear methods of low-bit(s) modulation against square-error distortion-constrained intentional attacks. We introduce a new form of dither modulation called spread-transform dither modulation that retains these favorable performance characteristics while achieving better performance against other attacks such as JPEG compression.
Efficient nearest neighbors via robust sparse hashing.
Cherian, Anoop; Sra, Suvrit; Morellas, Vassilios; Papanikolopoulos, Nikolaos
2014-08-01
This paper presents a new nearest neighbor (NN) retrieval framework: robust sparse hashing (RSH). Our approach is inspired by the success of dictionary learning for sparse coding. Our key idea is to sparse code the data using a learned dictionary, and then to generate hash codes out of these sparse codes for accurate and fast NN retrieval. But, direct application of sparse coding to NN retrieval poses a technical difficulty: when data are noisy or uncertain (which is the case with most real-world data sets), for a query point, an exact match of the hash code generated from the sparse code seldom happens, thereby breaking the NN retrieval. Borrowing ideas from robust optimization theory, we circumvent this difficulty via our novel robust dictionary learning and sparse coding framework called RSH, by learning dictionaries on the robustified counterparts of the perturbed data points. The algorithm is applied to NN retrieval on both simulated and real-world data. Our results demonstrate that RSH holds significant promise for efficient NN retrieval against the state of the art.
Real Time & Power Efficient Adaptive - Robust Control
Ioan Gliga, Lavinius; Constantin Mihai, Cosmin; Lupu, Ciprian; Popescu, Dumitru
2017-01-01
A design procedure for a control system suited for dynamic variable processes is presented in this paper. The proposed adaptive - robust control strategy considers both adaptive control advantages and robust control benefits. It estimates the degradation of the system’s performances due to the dynamic variation in the process and it then utilizes it to determine when the system must be adapted with a redesign of the robust controller. A single integral criterion is used for the identification of the process, and for the design of the control algorithm, which is expressed in direct form, through a cost function defined in the space of the parameters of both the process and the controller. For the minimization of this nonlinear function, an adequate mathematical programming minimization method is used. The theoretical approach presented in this paper was validated for a closed loop control system, simulated in an application developed in C. Because of the reduced number of operations, this method is suitable for implementation on fast processes. Due to its effectiveness, it increases the idle time of the CPU, thereby saving electrical energy.
High-performance quantitative robust switching control for optical telescopes
Lounsbury, William P.; Garcia-Sanz, Mario
2014-07-01
This paper introduces an innovative robust and nonlinear control design methodology for high-performance servosystems in optical telescopes. The dynamics of optical telescopes typically vary according to azimuth and altitude angles, temperature, friction, speed and acceleration, leading to nonlinearities and plant parameter uncertainty. The methodology proposed in this paper combines robust Quantitative Feedback Theory (QFT) techniques with nonlinear switching strategies that achieve simultaneously the best characteristics of a set of very active (fast) robust QFT controllers and very stable (slow) robust QFT controllers. A general dynamic model and a variety of specifications from several different commercially available amateur Newtonian telescopes are used for the controller design as well as the simulation and validation. It is also proven that the nonlinear/switching controller is stable for any switching strategy and switching velocity, according to described frequency conditions based on common quadratic Lyapunov functions (CQLF) and the circle criterion.
Robust MMSE Transceiver Designs for Downlink MIMO Systems with Multicell Cooperation
Directory of Open Access Journals (Sweden)
Jialing Li
2010-01-01
Full Text Available The robust-generalized iterative approach (Robust-GIA, robust-fast iterative approach (Robust-FIA, and robust-decoder covariance optimization approach (Robust-DCOA are proposed for designing MMSE transceivers of downlink multicell multiuser MIMO systems with per-cell and per-antenna power constraints and possibly imperfect channel state information. The Robust-DCOA is the most restrictive but is always optimum, the Robust-GIA is the most general, and the Robust-FIA is the most efficient. When the Robust-DCOA is applicable and the decoder covariance matrices are full rank, the three proposed approaches are equivalent and all provide the optimum solution. Numerical results show that the proposed robust approaches outperform their non-robust counterparts in various single-cell and multicell examples with different system configurations, channel correlations, power constraints, and cooperation scenarios. Moreover, performances of the robust approaches are insensitive to estimation errors of channel statistics (correlations and path loss. With cell-cooperation, cell edge interference problems can be remedied without reducing the number of data streams by using the proposed robust approaches.
Heo, Gaeun; Pyo, Kyoung-Hee; Lee, Da Hee; Kim, Youngmin; Kim, Jong-Woong
2016-05-01
This paper presents the successful fabrication of a transparent electrode comprising a sandwich structure of silicone/Ag nanowires (AgNWs)/silicone equipped with Diels-Alder (DA) adducts as crosslinkers to realise highly stable stretchability. Because of the reversible DA reaction, the crosslinked silicone successfully bonds with the silicone overcoat, which should completely seal the electrode. Thus, any surrounding liquid cannot leak through the interfaces among the constituents. Furthermore, the nanowires are protected by the silicone cover when they are stressed by mechanical loads such as bending, folding, and stretching. After delicate optimisation of the layered silicone/AgNW/silicone sandwich structure, a stretchable transparent electrode which can withstand 1000 cycles of 50% stretching-releasing with an exceptionally high stability and reversibility was fabricated. This structure can be used as a transparent strain sensor; it possesses a strong piezoresistivity with a gauge factor greater than 11.
Zuelicke, U
2012-01-01
The most fundamental characteristics of a physical system can often be deduced from its behaviour under discrete symmetry transformations such as time reversal, parity and chirality. Here we review basic symmetry properties of the relativistic quantum theories for free electrons in (2+1)- and (1+1)-dimensional spacetime. Additional flavour degrees of freedom are necessary to properly define symmetry operations in (2+1) dimensions and are generally present in physical realisations of such systems, e.g., in single sheets of graphite. We find that there exist two possibilities for defining any flavour-coupling discrete symmetry operation of the two-flavour (2+1)-dimensional Dirac theory. Physical implications of this duplicity are discussed.
Yang, Qianli; Pitkow, Xaq
2015-03-01
Most interesting natural sensory stimuli are encoded in the brain in a form that can only be decoded nonlinearly. But despite being a core function of the brain, nonlinear population codes are rarely studied and poorly understood. Interestingly, the few existing models of nonlinear codes are inconsistent with known architectural features of the brain. In particular, these codes have information content that scales with the size of the cortical population, even if that violates the data processing inequality by exceeding the amount of information entering the sensory system. Here we provide a valid theory of nonlinear population codes by generalizing recent work on information-limiting correlations in linear population codes. Although these generalized, nonlinear information-limiting correlations bound the performance of any decoder, they also make decoding more robust to suboptimal computation, allowing many suboptimal decoders to achieve nearly the same efficiency as an optimal decoder. Although these correlations are extremely difficult to measure directly, particularly for nonlinear codes, we provide a simple, practical test by which one can use choice-related activity in small populations of neurons to determine whether decoding is suboptimal or optimal and limited by correlated noise. We conclude by describing an example computation in the vestibular system where this theory applies. QY and XP was supported by a grant from the McNair foundation.
Robust Principal Component Analysis?
Candes, Emmanuel J; Ma, Yi; Wright, John
2009-01-01
This paper is about a curious phenomenon. Suppose we have a data matrix, which is the superposition of a low-rank component and a sparse component. Can we recover each component individually? We prove that under some suitable assumptions, it is possible to recover both the low-rank and the sparse components exactly by solving a very convenient convex program called Principal Component Pursuit; among all feasible decompositions, simply minimize a weighted combination of the nuclear norm and of the L1 norm. This suggests the possibility of a principled approach to robust principal component analysis since our methodology and results assert that one can recover the principal components of a data matrix even though a positive fraction of its entries are arbitrarily corrupted. This extends to the situation where a fraction of the entries are missing as well. We discuss an algorithm for solving this optimization problem, and present applications in the area of video surveillance, where our methodology allows for th...
Robust relativistic bit commitment
Chakraborty, Kaushik; Chailloux, André; Leverrier, Anthony
2016-12-01
Relativistic cryptography exploits the fact that no information can travel faster than the speed of light in order to obtain security guarantees that cannot be achieved from the laws of quantum mechanics alone. Recently, Lunghi et al. [Phys. Rev. Lett. 115, 030502 (2015), 10.1103/PhysRevLett.115.030502] presented a bit-commitment scheme where each party uses two agents that exchange classical information in a synchronized fashion, and that is both hiding and binding. A caveat is that the commitment time is intrinsically limited by the spatial configuration of the players, and increasing this time requires the agents to exchange messages during the whole duration of the protocol. While such a solution remains computationally attractive, its practicality is severely limited in realistic settings since all communication must remain perfectly synchronized at all times. In this work, we introduce a robust protocol for relativistic bit commitment that tolerates failures of the classical communication network. This is done by adding a third agent to both parties. Our scheme provides a quadratic improvement in terms of expected sustain time compared with the original protocol, while retaining the same level of security.
Indian Academy of Sciences (India)
M Sankar Kishore; K Veerabhadra Rao
2001-06-01
Correlation tracking plays an important role in the automation of weapon systems. Area correlation is an effective technique for tracking targets that have neither prominent features nor high contrast with the background and the ‘target’ can even be an area or a scene of interest. Even though this technique is robust under varying conditions of target background and light conditions, it has some problems like target drift and false registration. When the tracker or target is moving, the registration point drifts due to the discrete pixel size and aspect angle change. In this research work, an attempt has been made to improve the performance of a correlation tracker for tracking ground targets with very poor contrast. In the present work only the CCD visible images with very poor target to background contrast are considered. Applying novel linear and nonlinear filters, the problems present in the correlation tracker are overcome. Confidence and redundancy measures have been proposed to improve the performance by detecting misregistration. The proposed algorithm is tested on different sequences of images and its performance is satisfactory.
FAST: FAST Analysis of Sequences Toolbox.
Lawrence, Travis J; Kauffman, Kyle T; Amrine, Katherine C H; Carper, Dana L; Lee, Raymond S; Becich, Peter J; Canales, Claudia J; Ardell, David H
2015-01-01
FAST (FAST Analysis of Sequences Toolbox) provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU's Not Unix) Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R, and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics make FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format). Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.
FAST: FAST Analysis of Sequences Toolbox
Directory of Open Access Journals (Sweden)
Travis J. Lawrence
2015-05-01
Full Text Available FAST (FAST Analysis of Sequences Toolbox provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU’s Not Unix Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics makes FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format. Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.
Robustness Evaluation of Timber Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard
2009-01-01
The present paper considers robustness evaluation of a Norwegian sports arena with a structural system of glulam frames. The robustness evaluation is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety of Structures and a probabilistic modelling...... of the timber material proposed in the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS). The results show that the requirements for robustness of the structure are highly related to the modelling of the snow load used on the structures when ‘removal of a limited part...
Carrion, Philip M.
1990-09-01
This paper can be considered as a continuation of the work by Carrion and Carneiro (1989), where a generalized approach to linearized inversion of geophysical data was developed. Their method allows one to incorporate virtually any constraints in the inversion and reformulate the problem in the dual space of Langrangian multipliers (see also Carrion, 1989a). The constrained tomography makes traveltime inversion robust: it automatically rejects “bad data” which correspond to solutions beyond the chosen constraints and allows one to start inversion with an arbitrary chosen initial model.In this paper, I will derive basic formulas for constrained tomographic imaging that can be used in such areas of geophysics as global mapping of the earth interior, exploration geophysics, etc. The method is fast: an example that will be shown in the paper took only 6 min. of VAX CPU time. Had the conventional least-squares matrix inversion been used it would have taken more than 10 hours of the CPU time to solve the same problem.
Energy Technology Data Exchange (ETDEWEB)
Carrion, P.M. (PPPG/UFBA - Campus Universitario da Federacao, Salvador-Bahia (Brazil))
1990-09-01
This paper can be considered as a continuation of the work by Carrion and Carneiro (1989), where a generalized approach to linearized inversion of geophysical data was developed. Their method allows one to incorporate virtually any constraints in the inversion and reformulate the problem in the dual space of Langrangian multipliers (see also Carrion, 1989a). The constrained tomography makes traveltime inversion robust: it automatically rejects bad data which correspond to solutions beyond the chosen constraints and allows one to start inversion with an arbitrary chosen initial model. In this paper, the author derives basic formulas for constrained tomographic imaging that can be used in such areas of geophysics as global mapping of the earth interior, exploration geophysics, etc. The method is fast: an example that will be shown in the paper took only 6 min. of VAX CPU time. Had the conventional least-squares matrix inversion been used it would have taken more than 10 hours of the CPU time to solve the same problem.
Robust levitation control for maglev systems with guaranteed bounded airgap.
Xu, Jinquan; Chen, Ye-Hwa; Guo, Hong
2015-11-01
The robust control design problem for the levitation control of a nonlinear uncertain maglev system is considered. The uncertainty is (possibly) fast time-varying. The system has magnitude limitation on the airgap between the suspended chassis and the guideway in order to prevent undesirable contact. Furthermore, the (global) matching condition is not satisfied. After a three-step state transformation, a robust control scheme for the maglev vehicle is proposed, which is able to guarantee the uniform boundedness and uniform ultimate boundedness of the system, regardless of the uncertainty. The magnitude limitation of the airgap is guaranteed, regardless of the uncertainty. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
A Robust Design Applicability Model
DEFF Research Database (Denmark)
Ebro, Martin; Lars, Krogstie; Howard, Thomas J.
2015-01-01
This paper introduces a model for assessing the applicability of Robust Design (RD) in a project or organisation. The intention of the Robust Design Applicability Model (RDAM) is to provide support for decisions by engineering management considering the relevant level of RD activities. The applic...
Robust and distributed hypothesis testing
Gül, Gökhan
2017-01-01
This book generalizes and extends the available theory in robust and decentralized hypothesis testing. In particular, it presents a robust test for modeling errors which is independent from the assumptions that a sufficiently large number of samples is available, and that the distance is the KL-divergence. Here, the distance can be chosen from a much general model, which includes the KL-divergence as a very special case. This is then extended by various means. A minimax robust test that is robust against both outliers as well as modeling errors is presented. Minimax robustness properties of the given tests are also explicitly proven for fixed sample size and sequential probability ratio tests. The theory of robust detection is extended to robust estimation and the theory of robust distributed detection is extended to classes of distributions, which are not necessarily stochastically bounded. It is shown that the quantization functions for the decision rules can also be chosen as non-monotone. Finally, the boo...
A Robust Enough Virtue Epistemology
DEFF Research Database (Denmark)
Broncano-Berrocal, Fernando
2016-01-01
What is the nature of knowledge? A popular answer to that long-standing question comes from robust virtue epistemology, whose key idea is that knowing is just a matter of succeeding cognitively—i.e., coming to believe a proposition truly—due to an exercise of cognitive ability. Versions of robust...
Robust Understanding of Statistical Variation
Peters, Susan A.
2011-01-01
This paper presents a framework that captures the complexity of reasoning about variation in ways that are indicative of robust understanding and describes reasoning as a blend of design, data-centric, and modeling perspectives. Robust understanding is indicated by integrated reasoning about variation within each perspective and across…
Robust statistical methods with R
Jureckova, Jana
2005-01-01
Robust statistical methods were developed to supplement the classical procedures when the data violate classical assumptions. They are ideally suited to applied research across a broad spectrum of study, yet most books on the subject are narrowly focused, overly theoretical, or simply outdated. Robust Statistical Methods with R provides a systematic treatment of robust procedures with an emphasis on practical application.The authors work from underlying mathematical tools to implementation, paying special attention to the computational aspects. They cover the whole range of robust methods, including differentiable statistical functions, distance of measures, influence functions, and asymptotic distributions, in a rigorous yet approachable manner. Highlighting hands-on problem solving, many examples and computational algorithms using the R software supplement the discussion. The book examines the characteristics of robustness, estimators of real parameter, large sample properties, and goodness-of-fit tests. It...
Minimax Robust Quickest Change Detection
Unnikrishnan, Jayakrishnan; Meyn, Sean
2009-01-01
The two popular criteria of optimality for quickest change detection procedures are Lorden's criterion and the Bayesian criterion. In this paper a robust version of these quickest change detection problems is considered when the pre-change and post-change distributions are not known exactly but belong to known uncertainty classes of distributions. For uncertainty classes that satisfy a specific condition, it is shown that one can identify least favorable distributions (LFDs) from the uncertainty classes, such that the detection rule designed for the LFDs is optimal for the robust problem in a minimax sense. The condition is similar to that required for the identification of LFDs for the robust hypothesis testing problem studied by Huber. An upper bound on the delay incurred by the robust test is also obtained in the asymptotic setting under Lorden's criterion of optimality, which quantifies the delay penalty incurred to guarantee robustness. When the LFDs can be identified, the proposed test is easier to impl...
Graph measures and network robustness
Ellens, W
2013-01-01
Network robustness research aims at finding a measure to quantify network robustness. Once such a measure has been established, we will be able to compare networks, to improve existing networks and to design new networks that are able to continue to perform well when it is subject to failures or attacks. In this paper we survey a large amount of robustness measures on simple, undirected and unweighted graphs, in order to offer a tool for network administrators to evaluate and improve the robustness of their network. The measures discussed in this paper are based on the concepts of connectivity (including reliability polynomials), distance, betweenness and clustering. Some other measures are notions from spectral graph theory, more precisely, they are functions of the Laplacian eigenvalues. In addition to surveying these graph measures, the paper also contains a discussion of their functionality as a measure for topological network robustness.
Robust classification using mixtures of dependency networks
DEFF Research Database (Denmark)
Gámez, José A.; Mateo, Juan L.; Nielsen, Thomas Dyhre
2008-01-01
Dependency networks have previously been proposed as alternatives to e.g. Bayesian networks by supporting fast algorithms for automatic learning. Recently dependency networks have also been proposed as classiﬁcation models, but as with e.g. general probabilistic inference, the reported speed......-ups are often obtained at the expense of accuracy. In this paper we try to address this issue through the use of mixtures of dependency networks. To reduce learning time and improve robustness when dealing with data sparse classes, we outline methods for reusing calculations across mixture components. Finally......, the proposed model is empirically compared to other state-of-the-art classiﬁers, both in terms of accuracy and learning time....
Lahtero, Tapio Juhani; Kuusilehto-Awale, Lea
2013-01-01
This article introduces a quantitative research into how the leadership team members of 49 basic education schools in the city of Vantaa, Finland, experienced the realisation of strategic leadership in their leadership teams' work. The data were collected by a survey of 24 statements, rated on a five-point Likert scale, and analysed with the…
Weiss, Felix; Steininger, Hanna-Marei
2013-01-01
In this article, we evaluate the impact of social origin on the realisation of educational intentions at the time of becoming eligible for higher education in Germany. In general, we find high persistence of intentions and actual attendance of higher education. However, effects of parental education on the changes of educational intentions…
Theoretical Framework for Robustness Evaluation
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard
2011-01-01
This paper presents a theoretical framework for evaluation of robustness of structural systems, incl. bridges and buildings. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, although...... the importance of robustness for structural design is widely recognized the code requirements are not specified in detail, which makes the practical use difficult. This paper describes a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines...
Robustness Analysis of Kinetic Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard
2009-01-01
The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...... systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture....
Population genetics of translational robustness.
Wilke, Claus O; Drummond, D Allan
2006-05-01
Recent work has shown that expression level is the main predictor of a gene's evolutionary rate and that more highly expressed genes evolve slower. A possible explanation for this observation is selection for proteins that fold properly despite mistranslation, in short selection for translational robustness. Translational robustness leads to the somewhat paradoxical prediction that highly expressed genes are extremely tolerant to missense substitutions but nevertheless evolve very slowly. Here, we study a simple theoretical model of translational robustness that allows us to gain analytic insight into how this paradoxical behavior arises.
Robustness of airline route networks
Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David
2016-03-01
Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.
Inconsistency Correction and Re-localization for Robust Collaborative SLAM
2014-04-24
for Robust Collaborative SLAM 5a. CONTRACT NUMBER FA2386-12-1-4093 5b. GRANT NUMBER Grant AOARD-124093 5c. PROGRAM ELEMENT NUMBER 61102F...CoSLAM system [1] – collaborative visual SLAM involving multiple cameras moving independently on different platforms. Firstly, we consider the...poses and a consistent 3D map. The other addressed issue is occasional failures of the SLAM system. Motion blur will be generated by fast motion of
Multifidelity Robust Aeroelastic Design Project
National Aeronautics and Space Administration — Nielsen Engineering & Research (NEAR) proposes a new method to generate mathematical models of wind-tunnel models and flight vehicles for robust aeroelastic...
Robust Portfolio Optimization Using Pseudodistances.
Toma, Aida; Leoni-Aubin, Samuela
2015-01-01
The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature.
Shaping Robust System through Evolution
Kaneko, Kunihiko
2008-01-01
Biological functions are generated as a result of developmental dynamics that form phenotypes governed by genotypes. The dynamical system for development is shaped through genetic evolution following natural selection based on the fitness of the phenotype. Here we study how this dynamical system is robust to noise during development and to genetic change by mutation. We adopt a simplified transcription regulation network model to govern gene expression, which gives a fitness function. Through simulations of the network that undergoes mutation and selection, we show that a certain level of noise in gene expression is required for the network to acquire both types of robustness. The results reveal how the noise that cells encounter during development shapes any network's robustness, not only to noise but also to mutations. We also establish a relationship between developmental and mutational robustness through phenotypic variances caused by genetic variation and epigenetic noise. A universal relationship betwee...
A robust chaotic algorithm for digital image steganography
Ghebleh, M.; Kanso, A.
2014-06-01
This paper proposes a new robust chaotic algorithm for digital image steganography based on a 3-dimensional chaotic cat map and lifted discrete wavelet transforms. The irregular outputs of the cat map are used to embed a secret message in a digital cover image. Discrete wavelet transforms are used to provide robustness. Sweldens' lifting scheme is applied to ensure integer-to-integer transforms, thus improving the robustness of the algorithm. The suggested scheme is fast, efficient and flexible. Empirical results are presented to showcase the satisfactory performance of our proposed steganographic scheme in terms of its effectiveness (imperceptibility and security) and feasibility. Comparison with some existing transform domain steganographic schemes is also presented.
Robust and Trend-following Kalman Smoothers using Student's t
Aravkin, Aleksandr Y; Pillonetto, Gianluigi
2011-01-01
We propose two nonlinear Kalman smoothers that rely on Student's t distributions. The T-Robust smoother finds the maximum a posteriori likelihood (MAP) solution for Gaussian process noise and Student's t observation noise, and is extremely robust against outliers, outperforming the recently proposed l1-Laplace smoother in extreme situations (e.g. 50% or more outliers). The second estimator, which we call the T-Trend smoother, is able to follow sudden changes in the process model, and is derived as a MAP solver for a model with Student's t-process noise and Gaussian observation noise. We design specialized methods to solve both problems which exploit the special structure of the Student's t-distribution, and provide a convergence theory. Both smoothers can be implemented with only minor modifications to an existing L2 smoother implementation. Numerical results for linear and nonlinear models illustrating both robust and fast tracking applications are presented.
Surface-preserving robust watermarking of 3-D shapes.
Luo, Ming; Bors, Adrian G
2011-10-01
This paper describes a new statistical approach for watermarking mesh representations of 3-D graphical objects. A robust digital watermarking method has to mitigate among the requirements of watermark invisibility, robustness, embedding capacity and key security. The proposed method employs a mesh propagation distance metric procedure called the fast marching method (FMM), which defines regions of equal geodesic distance width calculated with respect to a reference location on the mesh. Each of these regions is used for embedding a single bit. The embedding is performed by changing the normalized distribution of local geodesic distances from within each region. Two different embedding methods are used by changing the mean or the variance of geodesic distance distributions. Geodesic distances are slightly modified statistically by displacing the vertices in their existing triangle planes. The vertex displacements, performed according to the FMM, ensure a minimal surface distortion while embedding the watermark code. Robustness to a variety of attacks is shown according to experimental results.
Robust inspection and interpretation techniques
Energy Technology Data Exchange (ETDEWEB)
Marriott, D.L. (Stress Engineering Services, Cincinnati, OH (United States))
1993-05-01
This paper explores the value of approximate methods of a specific type, as an efficient aid to performing residual life assessments, particularly when input data are incomplete. These methods, referred to as [open quotes]robust[close quotes] have the desirable attributes of providing satisfactory answers using less-than-perfect input, and being very economical in time of execution. Some examples of robust methods, which have been used successfully in high temperature design and fracture evaluations, are presented. 17 refs., 12 figs.
Robust methods for data reduction
Farcomeni, Alessio
2015-01-01
Robust Methods for Data Reduction gives a non-technical overview of robust data reduction techniques, encouraging the use of these important and useful methods in practical applications. The main areas covered include principal components analysis, sparse principal component analysis, canonical correlation analysis, factor analysis, clustering, double clustering, and discriminant analysis.The first part of the book illustrates how dimension reduction techniques synthesize available information by reducing the dimensionality of the data. The second part focuses on cluster and discriminant analy
Population genetics of translational robustness
Wilke, Claus O; Drummond, D. Allan
2005-01-01
Recent work has shown that expression level is the main predictor of a gene’s evolutionary rate, and that more highly expressed genes evolve slower. A possible explanation for this observation is selection for proteins which fold properly despite mistranslation, in short selection for translational robustness. Translational robustness leads to the somewhat paradoxical prediction that highly expressed genes are extremely tolerant to missense substitutions but nevertheless evolve very slo...
Kwakkel, Jan; Haasnoot, Marjolijn
2015-04-01
In response to climate and socio-economic change, in various policy domains there is increasingly a call for robust plans or policies. That is, plans or policies that performs well in a very large range of plausible futures. In the literature, a wide range of alternative robustness metrics can be found. The relative merit of these alternative conceptualizations of robustness has, however, received less attention. Evidently, different robustness metrics can result in different plans or policies being adopted. This paper investigates the consequences of several robustness metrics on decision making, illustrated here by the design of a flood risk management plan. A fictitious case, inspired by a river reach in the Netherlands is used. The performance of this system in terms of casualties, damages, and costs for flood and damage mitigation actions is explored using a time horizon of 100 years, and accounting for uncertainties pertaining to climate change and land use change. A set of candidate policy options is specified up front. This set of options includes dike raising, dike strengthening, creating more space for the river, and flood proof building and evacuation options. The overarching aim is to design an effective flood risk mitigation strategy that is designed from the outset to be adapted over time in response to how the future actually unfolds. To this end, the plan will be based on the dynamic adaptive policy pathway approach (Haasnoot, Kwakkel et al. 2013) being used in the Dutch Delta Program. The policy problem is formulated as a multi-objective robust optimization problem (Kwakkel, Haasnoot et al. 2014). We solve the multi-objective robust optimization problem using several alternative robustness metrics, including both satisficing robustness metrics and regret based robustness metrics. Satisficing robustness metrics focus on the performance of candidate plans across a large ensemble of plausible futures. Regret based robustness metrics compare the
U.S. Department of Health & Human Services — HCUP Fast Stats provides easy access to the latest HCUP-based statistics for health information topics. HCUP Fast Stats uses visual statistical displays in...
Fast foods are quick, reasonably priced, and readily available alternatives to home cooking. While convenient and economical for a busy lifestyle, fast foods are typically high in calories, fat, saturated ...
... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ...
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole; Hansen, Peter Reinhard; Lunde, Asger
which has these three properties which are all essential for empirical work in this area. We derive the large sample asymptotics of this estimator and assess its accuracy using a Monte Carlo study. We implement the estimator on some US equity data, comparing our results to previous work which has used...
Institute of Scientific and Technical Information of China (English)
何春晗; 夏明飞; 周张华
2014-01-01
火箭主动段飞行过程中，由于测控设备失效，导致测量数据丢失，设备恢复后无法快速重捕目标。利用某点测量数据的速度值，参考理论弹道上最相近速度值，引入科氏力概念，通过对变质量质点的运动力学分析，实现数据修正及弹道的外推。以MFC为软件应用平台，研究实现一种新型运载火箭飞行引导机制软件。试验表明，该新型运载火箭飞行引导机制，能够高精度、全弧段实现火箭飞行主动段的有效引导。并且基于MFC平台的软件系统具有很强的灵活性和可操作性。%In rocket’s powered flight process,since the failure of monitoring and control equipment,it causes the measured data miss and unable to fast re-capture the target after the equipment being recovered.To solve the problem,by using the speed value of measured data at certain point,referring to the most appropriate speed value in theoretical trajectory,and introducing Coriolis force concept,we realise the data revision and trajectory extrapolation through kinematics analysis on variable mass particles.Furthermore,we study and implement a novel flight guidance mechanism software for launch vehicle by taking MFC as the software application platform.Tests show that the new guidance mechanism can realise effective guidance in powered flight phase of the rocket with high precision and whole arc,the MFC platform-based software system has very good flexibility and operability.
Garber, Andrea K; Lustig, Robert H
2011-09-01
Studies of food addiction have focused on highly palatable foods. While fast food falls squarely into that category, it has several other attributes that may increase its salience. This review examines whether the nutrients present in fast food, the characteristics of fast food consumers or the presentation and packaging of fast food may encourage substance dependence, as defined by the American Psychiatric Association. The majority of fast food meals are accompanied by a soda, which increases the sugar content 10-fold. Sugar addiction, including tolerance and withdrawal, has been demonstrated in rodents but not humans. Caffeine is a "model" substance of dependence; coffee drinks are driving the recent increase in fast food sales. Limited evidence suggests that the high fat and salt content of fast food may increase addictive potential. Fast food restaurants cluster in poorer neighborhoods and obese adults eat more fast food than those who are normal weight. Obesity is characterized by resistance to insulin, leptin and other hormonal signals that would normally control appetite and limit reward. Neuroimaging studies in obese subjects provide evidence of altered reward and tolerance. Once obese, many individuals meet criteria for psychological dependence. Stress and dieting may sensitize an individual to reward. Finally, fast food advertisements, restaurants and menus all provide environmental cues that may trigger addictive overeating. While the concept of fast food addiction remains to be proven, these findings support the role of fast food as a potentially addictive substance that is most likely to create dependence in vulnerable populations.
Robust Schur Stability and Robust H^2 Performance
DEFF Research Database (Denmark)
Stoustrup, Jakob; Zhao, K.-Y.
1996-01-01
In this paper we address the problems of robust stability androbust QTR H^2 performance for uncertain discrete time systemswith nonlinear parametric uncertainties. We consider two families ofsystems with parametric uncertainties described by state space modelswhich offer a fairly general...... representation of most uncertain systemswith one or two parameters (the approach can be extended to more parameters).For these two families we obtain explicit expressions for the Schurstability radius and for the QTR H^2 robust performance radiusin the case of uncertainties with a single parameter. Moreover, we...
Santos, Abel; Yoo, Jeong Ha; Rohatgi, Charu Vashisth; Kumeria, Tushar; Wang, Ye; Losic, Dusan
2016-01-01
This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic mode is used with the aim of engineering the effective medium of NAA in a sinusoidal fashion. A precise control over the different anodisation parameters (i.e. anodisation period, anodisation amplitude, anodisation offset, number of pulses, anodisation temperature and pore widening time) makes it possible to engineer the characteristic reflection peaks and interferometric colours of NAA-RFs, which can be finely tuned across the UV-visible-NIR spectrum. The effect of the aforementioned anodisation parameters on the photonic properties of NAA-RFs (i.e. characteristic reflection peaks and interferometric colours) is systematically assessed in order to establish for the first time a comprehensive rationale towards NAA-RFs with fully controllable photonic properties. The experimental results are correlated with a theoretical model (Looyenga-Landau-Lifshitz - LLL), demonstrating that the effective medium of these photonic nanostructures can be precisely described by the effective medium approximation. NAA-RFs are also demonstrated as chemically selective photonic platforms combined with reflectometric interference spectroscopy (RIfS). The resulting optical sensing system is used to assess the reversible binding affinity between a model drug (i.e. indomethacin) and human serum albumin (HSA) in real-time. Our results demonstrate that this system can be used to determine the overall pharmacokinetic profile of drugs, which is a critical aspect to be considered for the implementation of efficient medical therapies.This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic
Robustness-tracking control based on sliding mode and H∞ theory for linear servo system
Institute of Scientific and Technical Information of China (English)
TIAN Yan-feng; GUO Qing-ding
2005-01-01
A robustness-tracking control scheme based on combining H∞ robust control and sliding mode control is proposed for a direct drive AC permanent-magnet linear motor servo system to solve the conflict between tracking and robustness of the linear servo system. The sliding mode tracking controller is designed to ensure the system has a fast tracking characteristic to the command, and the H∞ robustness controller suppresses the disturbances well within the close loop( including the load and the end effect force of linear motor etc. ) and effectively minimizes the chattering of sliding mode control which influences the steady state performance of the system. Simulation results show that this control scheme enhances the track-command-ability and the robustness of the linear servo system, and in addition, it has a strong robustness to parameter variations and resistance disturbances.
Directory of Open Access Journals (Sweden)
Scherpbier Albert
2007-07-01
Full Text Available Abstract Background An increasing number of newly trained Dutch GPs prefer to work in a group practice and as a non-principal rather than in a single-handed practice. In view of the greater number of female doctors, changing practice preferences, and discussions on future workforce problems, the question is whether male and female GPs were able to realise their initial preferences in the past and will be able to do so in the future. Methods We have conducted longitudinal cohort study of all GPs in the Netherlands seeking a practice between 1980 and 2004. The Netherlands Institute of Health Services Research (NIVEL in Utrecht collected the data used in this study by means of a postal questionnaire. The overall mean response rate was 94%. Results Over the past 20 years, an increasing proportion of GPs, both male and female, were able to achieve their preference for working in a group practice and/or in a non-principal position. Relatively more women than men have settled in group practices, and more men than women in single-handed practices; however, the practice preference of men and women is beginning to converge. Dropout was highest among the GPs without any specific practice preference. Conclusion The overwhelming preference of male and female GPs for working in group practices is apparently being met by the number of positions (principal or non-principal available in group practices. The preference of male and female GPs regarding the type of practice and job conditions is expected to converge further in the near future.
Santos, Abel; Yoo, Jeong Ha; Rohatgi, Charu Vashisth; Kumeria, Tushar; Wang, Ye; Losic, Dusan
2016-01-21
This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic mode is used with the aim of engineering the effective medium of NAA in a sinusoidal fashion. A precise control over the different anodisation parameters (i.e. anodisation period, anodisation amplitude, anodisation offset, number of pulses, anodisation temperature and pore widening time) makes it possible to engineer the characteristic reflection peaks and interferometric colours of NAA-RFs, which can be finely tuned across the UV-visible-NIR spectrum. The effect of the aforementioned anodisation parameters on the photonic properties of NAA-RFs (i.e. characteristic reflection peaks and interferometric colours) is systematically assessed in order to establish for the first time a comprehensive rationale towards NAA-RFs with fully controllable photonic properties. The experimental results are correlated with a theoretical model (Looyenga-Landau-Lifshitz - LLL), demonstrating that the effective medium of these photonic nanostructures can be precisely described by the effective medium approximation. NAA-RFs are also demonstrated as chemically selective photonic platforms combined with reflectometric interference spectroscopy (RIfS). The resulting optical sensing system is used to assess the reversible binding affinity between a model drug (i.e. indomethacin) and human serum albumin (HSA) in real-time. Our results demonstrate that this system can be used to determine the overall pharmacokinetic profile of drugs, which is a critical aspect to be considered for the implementation of efficient medical therapies.
Ramadan, fasting and pregnancy
DEFF Research Database (Denmark)
Ahmed, Urfan Zahoor; Lykke, Jacob Alexander
2014-01-01
In Islam, the month of Ramadan is a period of fasting lasting 29 or 30 days. Epidemiological studies among Muslims in Denmark have not been conducted, but studies show, that fasting among pregnant Muslim women is common. Fasting does not increase the risk of growth restriction or preterm delivery......, but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...
Attractive ellipsoids in robust control
Poznyak, Alexander; Azhmyakov, Vadim
2014-01-01
This monograph introduces a newly developed robust-control design technique for a wide class of continuous-time dynamical systems called the “attractive ellipsoid method.” Along with a coherent introduction to the proposed control design and related topics, the monograph studies nonlinear affine control systems in the presence of uncertainty and presents a constructive and easily implementable control strategy that guarantees certain stability properties. The authors discuss linear-style feedback control synthesis in the context of the above-mentioned systems. The development and physical implementation of high-performance robust-feedback controllers that work in the absence of complete information is addressed, with numerous examples to illustrate how to apply the attractive ellipsoid method to mechanical and electromechanical systems. While theorems are proved systematically, the emphasis is on understanding and applying the theory to real-world situations. Attractive Ellipsoids in Robust Control will a...
A Robust Enough Virtue Epistemology
DEFF Research Database (Denmark)
Broncano-Berrocal, Fernando
2016-01-01
What is the nature of knowledge? A popular answer to that long-standing question comes from robust virtue epistemology, whose key idea is that knowing is just a matter of succeeding cognitively—i.e., coming to believe a proposition truly—due to an exercise of cognitive ability. Versions of robust...... virtue epistemology further developing and systematizing this idea offer different accounts of the relation that must hold between an agent’s cognitive success and the exercise of her cognitive abilities as well as of the very nature of those abilities. This paper aims to give a new robust virtue...... epistemological account of knowledge based on a different understanding of the nature and structure of the kind of abilities that give rise to knowledge....
Advances in robust fractional control
Padula, Fabrizio
2015-01-01
This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...
Robust estimation and hypothesis testing
Tiku, Moti L
2004-01-01
In statistical theory and practice, a certain distribution is usually assumed and then optimal solutions sought. Since deviations from an assumed distribution are very common, one cannot feel comfortable with assuming a particular distribution and believing it to be exactly correct. That brings the robustness issue in focus. In this book, we have given statistical procedures which are robust to plausible deviations from an assumed mode. The method of modified maximum likelihood estimation is used in formulating these procedures. The modified maximum likelihood estimators are explicit functions of sample observations and are easy to compute. They are asymptotically fully efficient and are as efficient as the maximum likelihood estimators for small sample sizes. The maximum likelihood estimators have computational problems and are, therefore, elusive. A broad range of topics are covered in this book. Solutions are given which are easy to implement and are efficient. The solutions are also robust to data anomali...
Onion structure and network robustness
Wu, Zhi-Xi; 10.1103/PhysRevE.84.026106
2011-01-01
In a recent work [Proc. Natl. Acad. Sci. USA 108, 3838 (2011)], Schneider et al. proposed a new measure for network robustness and investigated optimal networks with respect to this quantity. For networks with a power-law degree distribution, the optimized networks have an onion structure-high-degree vertices forming a core with radially decreasing degrees and an over-representation of edges within the same radial layer. In this paper we relate the onion structure to graphs with good expander properties (another characterization of robust network) and argue that networks of skewed degree distributions with large spectral gaps (and thus good expander properties) are typically onion structured. Furthermore, we propose a generative algorithm producing synthetic scale-free networks with onion structure, circumventing the optimization procedure of Schneider et al. We validate the robustness of our generated networks against malicious attacks and random removals.
Robust Disaster Recovery System Model
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Highly security-critical system should possess features of continuous service. We present a new Robust Disaster Recovery System Model (RDRSM). Through strengthening the ability of safe communications, RDRSM guarantees the secure and reliable command on disaster recovery. Its self-supervision capability can monitor the integrality and security of disaster recovery system itself. By 2D and 3D real-time visible platform provided by GIS, GPS and RS, the model makes the using, management and maintenance of disaster recovery system easier. RDRSM possesses predominant features of security, robustness and controllability. And it can be applied to highly security-critical environments such as E-government and bank. Conducted by RDRSM, an important E-government disaster recovery system has been constructed successfully. The feasibility of this model is verified by practice. We especially emphasize the significance of some components of the model, such as risk assessment, disaster recovery planning, system supervision and robust communication support.
Robustness of digital artist authentication
DEFF Research Database (Denmark)
Jacobsen, Robert; Nielsen, Morten
In many cases it is possible to determine the authenticity of a painting from digital reproductions of the paintings; this has been demonstrated for a variety of artists and with different approaches. Common to all these methods in digital artist authentication is that the potential of the method...... is in focus, while the robustness has not been considered, i.e. the degree to which the data collection process influences the decision of the method. However, in order for an authentication method to be successful in practice, it needs to be robust to plausible error sources from the data collection....... In this paper we investigate the robustness of the newly proposed authenticity method introduced by the authors based on second generation multiresolution analysis. This is done by modelling a number of realistic factors that can occur in the data collection....
Robust Hitting with Dynamics Shaping
Yashima, Masahito; Yamawaki, Tasuku
The present paper proposes the trajectory planning based on “the dynamics shaping” for a redundant robotic arm to hit a target robustly toward the desired direction, of which the concept is to shape the robot dynamics appropriately by changing its posture in order to achieve the robust motion. The positional error of the end-effector caused by unknown disturbances converges onto near the singular vector corresponding to its maximum singular value of the output controllability matrix of the robotic arm. Therefore, if we can control the direction of the singular vector by applying the dynamics shaping, we will be able to control the direction of the positional error of the end-effector caused by unknown disturbances. We propose a novel trajectory planning based on the dynamics shaping and verify numerically and experimentally that the robotic arm can robustly hit the target toward the desired direction with a simple open-loop control system even though the disturbance is applied.
Robust Watermarking of Cartographic Images
Directory of Open Access Journals (Sweden)
Mauro Barni
2002-02-01
Full Text Available We present a method (Text-Based Geometric NormalizationÃ¢Â€Â”TBGN which, by exploiting the particular content of cartographic images, namely text content, permits to cope with global geometric transformations. First, text is extracted from the to-be-marked map, then text orientation and size are exploited to normalize the image geometry prior to watermark insertion. Watermarking is performed by means of any of the existing algorithms ensuring good robustness against image processing tools. At the decoder side, text is extracted again from the map and used to normalize image geometry. Owing to the robustness of text features with respect to common image manipulations, and to the likely spreading of text all across the digital map, the proposed system exhibits an excellent robustness.
Integrative Physiology of Fasting.
Secor, Stephen M; Carey, Hannah V
2016-03-15
Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.
Robust Schur Stability and Robust H^2 Performance
DEFF Research Database (Denmark)
Stoustrup, Jakob; Zhao, K.-Y.
1996-01-01
In this paper we address the problems of robust stability androbust QTR H^2 performance for uncertain discrete time systemswith nonlinear parametric uncertainties. We consider two families ofsystems with parametric uncertainties described by state space modelswhich offer a fairly general represen...
Asymptotics of robust utility maximization
Knispel, Thomas
2012-01-01
For a stochastic factor model we maximize the long-term growth rate of robust expected power utility with parameter $\\lambda\\in(0,1)$. Using duality methods the problem is reformulated as an infinite time horizon, risk-sensitive control problem. Our results characterize the optimal growth rate, an optimal long-term trading strategy and an asymptotic worst-case model in terms of an ergodic Bellman equation. With these results we propose a duality approach to a "robust large deviations" criterion for optimal long-term investment.
Walatka, Pamela P.; Clucas, Jean; McCabe, R. Kevin; Plessel, Todd; Potter, R.; Cooper, D. M. (Technical Monitor)
1994-01-01
The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system
Robust optimisation for self-scheduling and bidding strategies of hybrid CSP-fossil power plants
DEFF Research Database (Denmark)
Pousinho, H.M.I.; Contreras, J.; Pinson, P.
2015-01-01
This paper describes a profit-maximisation model for a hybrid concentrated solar power (CSP) producer participating in a day-ahead market with bilateral contracts, where there is no correlation between the electricity market price and the solar irradiation. Backup system coordination is included...... between the molten-salt thermal energy storage (TES) and a fossil-fuel backup to overcome solar irradiation insufficiency, but with emission allowances constrained in the backup system to mitigate carbon footprint. A robust optimisation-based approach is proposed to provide the day-ahead self......-schedule under the worst-case realisation of uncertainties due to the electricity market prices and the thermal production from the solar field (SF). These uncertainties are modelled by asymmetric prediction intervals around average values. Additionally, a budget parameter is used to parameterise the degree...
Robust dual-response optimization
Yanikoglu, Ihsan; den Hertog, Dick; Kleijnen, J.P.C.
2016-01-01
This article presents a robust optimization reformulation of the dual-response problem developed in response surface methodology. The dual-response approach fits separate models for the mean and the variance and analyzes these two models in a mathematical optimization setting. We use metamodels esti
Theoretical Framework for Robustness Evaluation
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard
2011-01-01
This paper presents a theoretical framework for evaluation of robustness of structural systems, incl. bridges and buildings. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, althou...
Robust control design with MATLAB
Gu, Da-Wei; Konstantinov, Mihail M
2013-01-01
Robust Control Design with MATLAB® (second edition) helps the student to learn how to use well-developed advanced robust control design methods in practical cases. To this end, several realistic control design examples from teaching-laboratory experiments, such as a two-wheeled, self-balancing robot, to complex systems like a flexible-link manipulator are given detailed presentation. All of these exercises are conducted using MATLAB® Robust Control Toolbox 3, Control System Toolbox and Simulink®. By sharing their experiences in industrial cases with minimum recourse to complicated theories and formulae, the authors convey essential ideas and useful insights into robust industrial control systems design using major H-infinity optimization and related methods allowing readers quickly to move on with their own challenges. The hands-on tutorial style of this text rests on an abundance of examples and features for the second edition: · rewritten and simplified presentation of theoretical and meth...
Robust Portfolio Optimization Using Pseudodistances
2015-01-01
The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature. PMID:26468948
Robust power system frequency control
Bevrani, Hassan
2008-01-01
Emphasizes the physical and engineering aspects of the power system frequency control design problem while providing a conceptual understanding of frequency regulation and application of robust control techniques. This book summarizes the author's research outcomes, contributions and experiences with power system frequency regulation.
Mental Models: A Robust Definition
Rook, Laura
2013-01-01
Purpose: The concept of a mental model has been described by theorists from diverse disciplines. The purpose of this paper is to offer a robust definition of an individual mental model for use in organisational management. Design/methodology/approach: The approach adopted involves an interdisciplinary literature review of disciplines, including…
Hints for practical robust optimization
Gorissen, B.L.; Yanikoglu, I.; den Hertog, D.
2013-01-01
Robust optimization (RO) is a young and active research field that has been mainly developed in the last 15 years. RO techniques are very useful for practice and not difficult to understand for practitioners. It is therefore remarkable that real-life applications of RO are still lagging behind; ther
Mental Models: A Robust Definition
Rook, Laura
2013-01-01
Purpose: The concept of a mental model has been described by theorists from diverse disciplines. The purpose of this paper is to offer a robust definition of an individual mental model for use in organisational management. Design/methodology/approach: The approach adopted involves an interdisciplinary literature review of disciplines, including…
Robust Simulations and Significant Separations
Fortnow, Lance
2010-01-01
We define and study a new notion of "robust simulations" between complexity classes which is intermediate between the traditional notions of infinitely-often and almost-everywhere, as well as a corresponding notion of "significant separations". A language L has a robust simulation in a complexity class C if there is a language in C which agrees with L on arbitrarily large polynomial stretches of input lengths. There is a significant separation of L from C if there is no robust simulation of L in C. The new notion of simulation is a cleaner and more natural notion of simulation than the infinitely-often notion. We show that various implications in complexity theory such as the collapse of PH if NP = P and the Karp-Lipton theorem have analogues for robust simulations. We then use these results to prove that most known separations in complexity theory, such as hierarchy theorems, fixed polynomial circuit lower bounds, time-space tradeoffs, and the theorems of Allender and Williams, can be strengthened to signifi...
A robust adaptive robot controller
Berghuis, Harry; Ortega, Romeo; Nijmeijer, Henk
1993-01-01
A globally convergent adaptive control scheme for robot motion control with the following features is proposed. First, the adaptation law possesses enhanced robustness with respect to noisy velocity measurements. Second, the controller does not require the inclusion of high gain loops that may excit
Koç, Y.
2015-01-01
Current and future trends in environmental, economical, and human-caused factors (such as power demand growth, over-ageing of assets in power grids, and extreme weather conditions) challenge power grid robustness in the near future, necessitating research to better analyse and understand the notion
BaSE-II: A Robust and Experimental PRS Receiver Development Platform
Rügamer, Alexander; Neumaier, Philipp; Sommer, Philipp; Garzia, Fabio; Rohmer, Günter; Konovaltsev, Andriy; Sgammini, Matteo; Meurer, Michael; Wendel, Jan; Schubert, Frank; Baumann, Stefan
2014-01-01
This paper features an experimental Galileo PRS receiver with a novel BOC tracking method and interference mitigation algorithms in time, frequency and spatial domain. The modified BaSE-II hardware architecture is outlined including a newly designed miniaturized 2x2 array antenna. A new, reliable and robust BOC tracking method is presented that fully exploits the subcarrier accuracy and allows reliable, fast and robust detection and correction of false locks to side pe...
DEFF Research Database (Denmark)
Kemmler, S.; Eifler, Tobias; Bertsche, B.
2015-01-01
products are and vice versa. For a comprehensive understanding and to use existing synergies between both domains, this paper discusses the basic principles of Reliability- and Robust Design theory. The development of a comprehensive model will enable an integrated consideration of both domains...
Professional Microsoft search fast search, Sharepoint search, and search server
Bennett, Mark; Kehoe, Miles; Voskresenskaya, Natalya
2010-01-01
Use Microsoft's latest search-based technology-FAST search-to plan, customize, and deploy your search solutionFAST is Microsoft's latest intelligent search-based technology that boasts robustness and an ability to integrate business intelligence with Search. This in-depth guide provides you with advanced coverage on FAST search and shows you how to use it to plan, customize, and deploy your search solution, with an emphasis on SharePoint 2010 and Internet-based search solutions.With a particular appeal for anyone responsible for implementing and managing enterprise search, this book presents t
Energy Technology Data Exchange (ETDEWEB)
Moreau, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1955-06-15
The two spectrometers have been achieved to tackle numerous problems of nuclear spectrometry. They possess different fields of application that complete themselves. The solenoidal spectrometer permits the determination of the energy limits of {beta} spectra and of their shape; it also permits the determination of the coefficients of internal conversion and reports {alpha}{sub K} / {alpha}{sub L} and it is especially efficient for the accurate energy levels of the {gamma} rays by photoelectric effect. The double coincidence spectrometer has been conceived to get a good efficiency in coincidence: indeed, the sum of the solid angles used for the {beta} and {gamma} emission is rather little lower to 4{pi} steradians. To get this efficiency, one should have sacrificed a little the resolution that is lower to the one obtained with the solenoidal spectrometer for a same brightness. Each of the elements of the double spectrometer can also be adapted to the study of angular correlations {beta}{gamma} and e{sup -}{gamma}. In this use, it is superior to the thin magnetic lens used up to here. The double spectrometer also permits the survey of the coincidences e{sup -}e{sup -}, e{sup -}{beta} of a equivalent way to a double lens; it can also be consider some adaptation for the survey of the angular correlations e{sup -}e{sup -}, e{sup -}{beta}. Finally, we applied the methods by simple spectrometry and by coincidence spectrometry, to the study of the radiances of the following radioelements: {sup 76}As (26 h), {sup 122}Sb (2,8 j), {sup 124}Sb (60 j), {sup 125}Sb (2,7 years). (M.B.) [French] Les deux spectrometres qui ont ete realises permettent d'aborder un grand nombre de problemes de spectrometrie nucleaire. Ils possedent des champs d'application tres differents qui se completent. Le spectrometre solenoidal permet la determination des energies limites des spectres {beta} et de leur forme; il permet aussi la determination des coefficients de conversion interne et
Algebraic connectivity and graph robustness.
Energy Technology Data Exchange (ETDEWEB)
Feddema, John Todd; Byrne, Raymond Harry; Abdallah, Chaouki T. (University of New Mexico)
2009-07-01
Recent papers have used Fiedler's definition of algebraic connectivity to show that network robustness, as measured by node-connectivity and edge-connectivity, can be increased by increasing the algebraic connectivity of the network. By the definition of algebraic connectivity, the second smallest eigenvalue of the graph Laplacian is a lower bound on the node-connectivity. In this paper we show that for circular random lattice graphs and mesh graphs algebraic connectivity is a conservative lower bound, and that increases in algebraic connectivity actually correspond to a decrease in node-connectivity. This means that the networks are actually less robust with respect to node-connectivity as the algebraic connectivity increases. However, an increase in algebraic connectivity seems to correlate well with a decrease in the characteristic path length of these networks - which would result in quicker communication through the network. Applications of these results are then discussed for perimeter security.
A Robust Streaming Media System
Youwei, Zhang
Presently, application layer multicast protocols (ALM) are proposed as substitute for IP multicast and have made extraordinary achievements. Integrated with Multi-data-stream mode such as Multiple Description Coding (MDC), ALM becomes more scalable and robust in high-dynamic Internet environment compared with single data stream. Although MDC can provide a flexible data transmission style, the synchronization of different descriptions encoded from one video source is proved to be difficult due to different delay on diverse transmission paths. In this paper, an ALM system called HMDC is proposed to improve accepted video quality of streaming media, hosts can join the separate overlay trees in different layers simultaneously, then the maximum synchronized descriptions of the same layer are worked out to acquire the best video quality. Simulations implemented on Internet-like topology indicate that HMDC achieves better video quality, lower link stress, higher robustness and comparable latency compared with traditional ALM protocols.
Robust estimation of Cronbach's alpha
2002-01-01
Cronbach’s alpha is a popular method to measure reliability, e.g. in quantifying the reliability of a score to summarize the information of several items in questionnaires. The alpha coefficient is known to be non-robust. We study the behavior of this coefficient in different settings to identify situations, which can easily occur in practice, but under which the Cronbach’s alpha coefficient is extremely sensitive to violations of the classical model assumptions. Furthermore, we construct a r...
Robust power system frequency control
Bevrani, Hassan
2014-01-01
This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi
A robust adaptive robot controller
1993-01-01
A globally convergent adaptive control scheme for robot motion control with the following features is proposed. First, the adaptation law possesses enhanced robustness with respect to noisy velocity measurements. Second, the controller does not require the inclusion of high gain loops that may excite the unmodeled dynamics and amplify the noise level. Third, we derive for the unknown parameter design a relationship between compensator gains and closed-loop convergence rates that is independen...
Robust nonlinear regression in applications
Lim, Changwon; Sen, Pranab K.; Peddada, Shyamal D.
2013-01-01
Robust statistical methods, such as M-estimators, are needed for nonlinear regression models because of the presence of outliers/influential observations and heteroscedasticity. Outliers and influential observations are commonly observed in many applications, especially in toxicology and agricultural experiments. For example, dose response studies, which are routinely conducted in toxicology and agriculture, sometimes result in potential outliers, especially in the high dose gr...
Development of Fast running DNBR Calculation Code
Energy Technology Data Exchange (ETDEWEB)
Kwon, Hyuk; Seo, K. W.; Kim, S. J.; Hwang, D. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2010-10-15
SMART core adopted a core protection(SCOPS) and a supervising system(SCOMS) to satisfy the SAFDL for AOO and normal operation. Generally, the criteria is limited to the DNBR limit so that the DNBR calculation module is required in the protection and the supervising system of core. There are CPU time limit and calculation robustness as some requirements of the DNBR calculation module in SCOPS and SCOMS caused by hardware limitations. The non-iterative few channel methods are needed to satisfy the requirements. Non-iterative numerical method is similar to the CETOP algorithm originated from ref. 1. The method is known as the non-iterative prediction and correction method. An optimum number of channels for core lumping model is selected as 4- channel which is same channel number of CETOP model. A compensation model of lumped channel is needed to ensure that the 4-channel thermal hydraulic field is nearly equivalent to that field of 1/8-core model that is calculated by MATRA-S. The code called FAST that is fast running DNBR calculation is developed to satisfy the requirements of CPU time and calculation robustness. Present paper is described of characteristics and calculation results of developed FAST code
Robust regularized singular value decomposition with application to mortality data
Zhang, Lingsong
2013-09-01
We develop a robust regularized singular value decomposition (RobRSVD) method for analyzing two-way functional data. The research is motivated by the application of modeling human mortality as a smooth two-way function of age group and year. The RobRSVD is formulated as a penalized loss minimization problem where a robust loss function is used to measure the reconstruction error of a low-rank matrix approximation of the data, and an appropriately defined two-way roughness penalty function is used to ensure smoothness along each of the two functional domains. By viewing the minimization problem as two conditional regularized robust regressions, we develop a fast iterative reweighted least squares algorithm to implement the method. Our implementation naturally incorporates missing values. Furthermore, our formulation allows rigorous derivation of leaveone- row/column-out cross-validation and generalized cross-validation criteria, which enable computationally efficient data-driven penalty parameter selection. The advantages of the new robust method over nonrobust ones are shown via extensive simulation studies and the mortality rate application. © Institute of Mathematical Statistics, 2013.
Robust Path Planning and Feedback Design Under Stochastic Uncertainty
Blackmore, Lars
2008-01-01
Autonomous vehicles require optimal path planning algorithms to achieve mission goals while avoiding obstacles and being robust to uncertainties. The uncertainties arise from exogenous disturbances, modeling errors, and sensor noise, which can be characterized via stochastic models. Previous work defined a notion of robustness in a stochastic setting by using the concept of chance constraints. This requires that mission constraint violation can occur with a probability less than a prescribed value.In this paper we describe a novel method for optimal chance constrained path planning with feedback design. The approach optimizes both the reference trajectory to be followed and the feedback controller used to reject uncertainty. Our method extends recent results in constrained control synthesis based on convex optimization to solve control problems with nonconvex constraints. This extension is essential for path planning problems, which inherently have nonconvex obstacle avoidance constraints. Unlike previous approaches to chance constrained path planning, the new approach optimizes the feedback gain as wellas the reference trajectory.The key idea is to couple a fast, nonconvex solver that does not take into account uncertainty, with existing robust approaches that apply only to convex feasible regions. By alternating between robust and nonrobust solutions, the new algorithm guarantees convergence to a global optimum. We apply the new method to an unmanned aircraft and show simulation results that demonstrate the efficacy of the approach.
Robust Path Planning and Feedback Design Under Stochastic Uncertainty
Blackmore, Lars
2008-01-01
Autonomous vehicles require optimal path planning algorithms to achieve mission goals while avoiding obstacles and being robust to uncertainties. The uncertainties arise from exogenous disturbances, modeling errors, and sensor noise, which can be characterized via stochastic models. Previous work defined a notion of robustness in a stochastic setting by using the concept of chance constraints. This requires that mission constraint violation can occur with a probability less than a prescribed value.In this paper we describe a novel method for optimal chance constrained path planning with feedback design. The approach optimizes both the reference trajectory to be followed and the feedback controller used to reject uncertainty. Our method extends recent results in constrained control synthesis based on convex optimization to solve control problems with nonconvex constraints. This extension is essential for path planning problems, which inherently have nonconvex obstacle avoidance constraints. Unlike previous approaches to chance constrained path planning, the new approach optimizes the feedback gain as wellas the reference trajectory.The key idea is to couple a fast, nonconvex solver that does not take into account uncertainty, with existing robust approaches that apply only to convex feasible regions. By alternating between robust and nonrobust solutions, the new algorithm guarantees convergence to a global optimum. We apply the new method to an unmanned aircraft and show simulation results that demonstrate the efficacy of the approach.
Real-time robust signal space separation for magnetoencephalography.
Guo, Chenlei; Li, Xin; Taulu, Samu; Wang, Wei; Weber, Douglas J
2010-08-01
In this paper, we develop a robust signal space separation (rSSS) algorithm for real-time magnetoencephalography (MEG) data processing. rSSS is based on the spatial signal space separation (SSS) method and it applies robust regression to automatically detect and remove bad MEG channels so that the results of SSS are not distorted. We extend the existing robust regression algorithm via three important new contributions: 1) a low-rank solver that efficiently performs matrix operations; 2) a subspace iteration scheme that selects bad MEG channels using low-order spherical harmonic functions; and 3) a parallel computing implementation that simultaneously runs multiple tasks to further speed up numerical computation. Our experimental results based on both simulation and measurement data demonstrate that rSSS offers superior accuracy over the traditional SSS algorithm, if the MEG data contain significant outliers. Taking advantage of the proposed fast algorithm, rSSS achieves more than 75 x runtime speedup compared to a direct solver of robust regression. Even though rSSS is currently implemented with MATLAB, it already provides sufficient throughput for real-time applications.
A Robust Deadbeat Control Method for UPS Inverters
Institute of Scientific and Technical Information of China (English)
汪孟; 李方正; 黄立培; SAKANE Makoto
2007-01-01
The traditional deadbeat control for UPS inverters has a robustness problem. The parametric imprecision can greatly harm the stability of the system, which restricts the application. A novel robust deadbeat control method is proposed in this paper to deal with the problem. In the proposed control method, a proportional element is added to the traditional deadbeat control in order to improve the robustness to parametric imprecision. To eliminate the error between output voltage and voltage reference caused by environmental noise and parametric deviation, a model reference adaptive regulator is also added to the control method. A 1kVA prototype is built based on DSP. Theoretical analysis and experimental results show that the robustness for parametric variation of the proposed method is much better than the traditional deadbeat control.The system can remain stable even when the systemic parameters have a large deviation from calculating parameters. The system has small static error and fast dynamic response with the new control method. This method is easy to realize in DSP and is suitable for full digital realization of UPS.
Microgrid Stability Controller Based on Adaptive Robust Total SMC
DEFF Research Database (Denmark)
Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.
2015-01-01
and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances......This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics....... The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing DG’s output power. When the microgrid is operating...
Mitigation of Remedial Action Schemes by Decentralized Robust Governor Control
Energy Technology Data Exchange (ETDEWEB)
Elizondo, Marcelo A.; Marinovici, Laurentiu D.; Lian, Jianming; Kalsi, Karanjit; Du, Pengwei
2014-04-15
This paper presents transient stability improvement by a new distributed hierarchical control architecture (DHC). The integration of remedial action schemes (RAS) to the distributed hierarchical control architecture is studied. RAS in power systems are designed to maintain stability and avoid undesired system conditions by rapidly switching equipment and/or changing operating points according to predetermined rules. The acceleration trend relay currently in use in the US western interconnection is an example of RAS that trips generators to maintain transient stability. The link between RAS and DHC is through fast acting robust turbine/governor control that can also improve transient stability. In this paper, the influence of the decentralized robust turbine/governor control on the design of RAS is studied. Benefits of combining these two schemes are increasing power transfer capability and mitigation of RAS generator tripping actions; the later benefit is shown through simulations.
A Robust Obstacle Avoidance for Service Robot Using Bayesian Approach
Directory of Open Access Journals (Sweden)
Widodo Budiharto
2011-03-01
Full Text Available The objective of this paper is to propose a robust obstacle avoidance method for service robot in indoor environment. The method for obstacles avoidance uses information about static obstacles on the landmark using edge detection. Speed and direction of people that walks as moving obstacle obtained by single camera using tracking and recognition system and distance measurement using 3 ultrasonic sensors. A new geometrical model and maneuvering method for moving obstacle avoidance introduced and combined with Bayesian approach for state estimation. The obstacle avoidance problem is formulated using decision theory, prior and posterior distribution and loss function to determine an optimal response based on inaccurate sensor data. Algorithms for moving obstacles avoidance method proposed and experiment results implemented to service robot also presented. Various experiments show that our proposed method very fast, robust and successfully implemented to service robot called Srikandi II that equipped with 4 DOF arm robot developed in our laboratory.
Z. Rico (Zulay)
2009-01-01
textabstractThe focus of this paper is on the influence of the fast growth of organizations on the design process of management control systems. What are the management accounting and control problems that a fast growth organization encounters that can be ascribed to this growth. What are the circum
Gelman, Hannah; Gruebele, Martin
2014-01-01
Fast folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast folding proteins has provided insight into the mechanisms which allow some proteins to find their native conformation well less than 1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even “slow” folding processes: fast folders are small, relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast folding proteins and provides an overview of the major findings of fast folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general as well as some work that is left to do. PMID:24641816
DEFF Research Database (Denmark)
Ahmed, Urfan Zahoor; Lykke, Jacob Alexander
2014-01-01
, but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...
Fast protein folding kinetics.
Gelman, Hannah; Gruebele, Martin
2014-05-01
Fast-folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast-folding proteins has provided insight into the mechanisms, which allow some proteins to find their native conformation well fast folders also informs our understanding of even 'slow' folding processes: fast folders are small; relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast-folding proteins and provides an overview of the major findings of fast-folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general, as well as some work that is left to do.
DEFF Research Database (Denmark)
Munk-Hansen, Carsten
Bogen er det tredje bind af tre planlagte bind om fast ejendom: I Overdragelsen, II Bolighandlen og III Ejerbeføjelsen. Fremstillingens giver et grundigt overblik over centrale områder af en omfattende regulering af fast ejendom, med angivelse af litteratur, hvor læseren kan søge yderligere...... oplysning. En ejer af fast ejendom er på særdeles mange områder begrænset i sin råden sammenlignet med ejeren af et formuegode i almindelighed. Fremstillingen tager udgangspunkt i ejerens perspektiv (fremfor samfundets eller myndighedernes). Både den privatretlige og offentligretlige regulering behandles......, eksempelvis ejendomsdannelsen, servitutter, naboretten, hævd, zoneinddelingen, den fysiske planlægning, beskyttelse af natur, beskyttelse af kultur, forurening fra fast ejendom, erstatning for forurening, jordforurening, ekspropriation, byggeri og adgang til fast ejendom....
Directory of Open Access Journals (Sweden)
Fereidoun Azizi
2013-07-01
Full Text Available The aim of this article is to review health-related aspects of Ramadan fasting in normal individuals and diabetics. During fasting days of Ramadan, glucose homeostasis is maintained by meal taken bepore dawn and by liver glycogen stores. Changes in serum lipids are variable and defend on the quality and quantity of food consumption and changes in weight. Compliant, well controlled type 2 diabetics may observe Ramadan fasting; but fasting is not recommended for type 1, non complaint, poorly controlled and pregnant diabetics. Although Ramadan fasting is safe for all healthy individuals and well controlled diabetics, those with uncontrolled diabetics and diabetics with complications should consult physicians and follow scientific recommendations.
Todd, Donald; Tsvetkov, Pavel
2012-01-01
Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...
Robustness in Railway Operations (RobustRailS)
DEFF Research Database (Denmark)
Jensen, Jens Parbo; Nielsen, Otto Anker
This study considers the problem of enhancing railway timetable robustness without adding slack time, hence increasing the travel time. The approach integrates a transit assignment model to assess how passengers adapt their behaviour whenever operations are changed. First, the approach considers...... the existing stopping patterns of the railway lines. Then, based on the passenger demand we try to optimize the overall utility by changing the stopping pattern in a way that capacity utilization is reduced without affecting the frequency of the train lines nor increasing the passengers’ travel time....
Pajewski, Lara; Benedetto, Andrea; D'Amico, Sebastiano; Ferrara, Vincenzo; Frezza, Fabrizio; Persico, Raffaele; Tosti, Fabio
2017-04-01
provided by the Italian company IDS Ingegneria dei Sistemi; in cooperation with the Spanish company Euroconsult, an instrumented lorry equipped with a curviameter was used in the same road sections. Curviameter and GPR results were compared, with very good agreement. 3. A reconfigurable stepped-frequency GPR prototype was improved and widely tested. The original version of this prototype was designed and realised in Italy, in 2008. In June 2014, with the support of the Action TU1208 (and in particular by exploiting the Short Term Scientific Mission (STSM) networking tool), this prototype was brought to Norway: tests were carried out in laboratory, on roads and archaelogical sites; results were compared with those obtained by using a commercial system manufactured by the Norwegian manufacturer 3d-radar. As a result of this work, it was possible to understand how to improve the Italian prototype. Changes to the hardware were implemented in cooperation with the company Florence Engineering. In the improved version of the prototype, a more advanced technique is used for the reconfiguration of the integration times. In July 2015, by exploiting again the STSM tool, the prototype was brought to Malta: tests were carried out in buildings, churches, archaeological and geological sites; results were compared with those obtained by using a commercial pulsed system manufactured by IDS Ingegneria dei Sistemi. It is worth pointing out that this was the first time GPR measurements were carried out in Malta, where no GPR systems are available. Finally, in January 2016 the improved prototype was again brought to Malta in order to be used during the experimental sessions of a TU1208 Training School. This is an excellent example of a successful scientific activity where STSM and TS COST networking tools were effectively exploited, the cooperation with industry was of central importance, and a less research-intensive Country was deliberately chosen, to test the improved system. 4. A cheap
A ROBUST EYE LOCALIZATION ALGORITHM FOR FACE RECOGNITION
Institute of Scientific and Technical Information of China (English)
Zhang Wencong; Li Xin; Yao Peng; Li Bin; Zhuang Zhenquan
2008-01-01
The accuracy of face alignment affects greatly the performance of a face recognition system.Since the face alignment is usually conducted using eye positions, the algorithm for accurate eye localization is essential for the accurate face recognition. In this paper, an algorithm is proposed for eye localization. First, the proper AdaBoost detection is adaptively trained to segment the region based on the special gray distribution in the region. After that, a fast radial symmetry operator is used to precisely locate the center of eyes. Experimental results show that the method can accurately locate the eyes, and it is robust to the variations of face poses, illuminations, expressions, and accessories.
Robust Stability Criterion for Uncertain Neural Networks with Time Delays
Institute of Scientific and Technical Information of China (English)
LIN Zhi-wei; ZHANG Ning; YANG Hong-jiu
2010-01-01
The robust stability of uncertain neural network with time-varying delay was investigated. The norm-bounded un-certainties are included in the system matrices. The constraint on time-varying delays is removed, which means that a fast time-varying delay is admissible. Some new delay-dependent stability criteria were presented by using Lyapunov-Krasovskii functional and linear matrix inequalities (LMIs) approaches. Finally, a numerical example was given to illustrate the effec-tiveness and innovation nature of the developed techniques.
Robust Design of Pilot-symbol-aided MIMO Channel Estimation
Institute of Scientific and Technical Information of China (English)
LUO Zhen-dong; LIU Yuan-an; GAO Jin-chun
2004-01-01
This paper investigates pilot-symbol-aided channel estimation/prediction for Multiple-Input Multiple-Output (MIMO) systems in fast fading environments. We first derive the design criteria of the optimal pilot blocks for energy, power and bandwidth-limited systems, respectively. Then two low-complexity channel estimation schemes are provided. Finally, we present a robust Minimum Mean Square Error (MMSE) channel estimator based on channel time correlation. Simulation shows the proposed MMSE estimator is considerably insensitive to channel statistics and significantly outperforms the traditional estimators with a low additional complexity in fast fading environments. By simply adjusting some parameters, the MMSE estimator can work as an estimator and a predictor simultaneously.
Robustness Analysis of Timber Truss Structure
DEFF Research Database (Denmark)
Rajčić, Vlatka; Čizmar, Dean; Kirkegaard, Poul Henning
2010-01-01
The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness...... evaluation of a widespan timber truss structure is presented. This structure was built few years ago near Zagreb and has a span of 45m. Reliability analysis of the main members and the system is conducted and based on this a robustness analysis is preformed....
Ylirisku, Vesa
2012-01-01
Building Blocks on the Sea – Simulating realisation of M2 Cell -concept in contemporary context on projektiin pohjautuva opinnäytetyö, jonka perustavana päämääränä on kehittää eteenpäin muunneltavaa moduulisysteemiä nimeltään M2Cell simuloimalla konseptin toimintaa nykyaikaisen risteilyteollisuuden kontekstissa. Toisin sanoen työn tavoitteena on vastata tämän innovatiivisen systeemin kehittämistarpeeseen niin uusien ideoiden kuin yleisen kehittämisenkin kautta keskittyen systeemin toiminnalli...
A novel robust approach for SLAM of mobile robot
Institute of Scientific and Technical Information of China (English)
马家辰; 张琦; 马立勇
2014-01-01
The task of simultaneous localization and mapping (SLAM) is to build environmental map and locate the position of mobile robot at the same time. FastSLAM 2.0 is one of powerful techniques to solve the SLAM problem. However, there are two obvious limitations in FastSLAM 2.0, one is the linear approximations of nonlinear functions which would cause the filter inconsistent and the other is the “particle depletion” phenomenon. A kind of PSO &H∞-based FastSLAM 2.0 algorithm is proposed. For maintaining the estimation accuracy,H∞ filter is used instead of EKF for overcoming the inaccuracy caused by the linear approximations of nonlinear functions. The unreasonable proposal distribution of particle greatly influences the pose state estimation of robot. A new sampling strategy based on PSO (particle swarm optimization) is presented to solve the “particle depletion” phenomenon and improve the accuracy of pose state estimation. The proposed approach overcomes the obvious drawbacks of standard FastSLAM 2.0 algorithm and enhances the robustness and efficiency in the parts of consistency of filter and accuracy of state estimation in SLAM. Simulation results demonstrate the superiority of the proposed approach.
Fast evaluation of the Rayleigh integral and applications to inverse acoustics
Wind, J.W.; Wijnant, Y.H.; Boer, de A.
2006-01-01
In this paper we present a fast evaluation of the Rayleigh integral, which leads to fast and robust solutions in inverse acoustics. The method commonly used to reconstruct acoustic sources on a plane in space is Planar Nearfield Acoustic Holography (PNAH). Some of the most important recent improveme
Sustainable Resilient, Robust & Resplendent Enterprises
DEFF Research Database (Denmark)
Edgeman, Rick
. Resilience may be regarded as enterprise ability to recover or rebound from negative shocks or extreme challenges to its ecosystem (Contu, 2002). Robustness, in contrast to resilience, is not so much enterprise ability to recover from shocks or challenges to its ecosystem, but rather resistance or immunity...... to their impact. Resplendent enterprises are introduced with resplendence referring not to some sort of public or private façade, but instead refers to organizations marked by dual brilliance and nobility of strategy, governance and comportment that yields superior and sustainable triple bottom line performance...
Robustness Evaluation of Timber Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Cizmar, D.
2010-01-01
The present paper outlines results from working group 3 (WG3) in the EU COST Action E55 – ‘Modelling of the performance of timber structures’. The objectives of the project are related to the three main research activities: the identification and modelling of relevant load and environmental...... exposure scenarios, the improvement of knowledge concerning the behaviour of timber structural elements and the development of a generic framework for the assessment of the life-cycle vulnerability and robustness of timber structures....
Robust and Sparse Factor Modelling
DEFF Research Database (Denmark)
Croux, Christophe; Exterkate, Peter
Factor construction methods are widely used to summarize a large panel of variables by means of a relatively small number of representative factors. We propose a novel factor construction procedure that enjoys the properties of robustness to outliers and of sparsity; that is, having relatively few...... nonzero factor loadings. Compared to the traditional factor construction method, we find that this procedure leads to a favorable forecasting performance in the presence of outliers and to better interpretable factors. We investigate the performance of the method in a Monte Carlo experiment...
Robust Adaptive Quantum Phase Estimation
Roy, Shibdas; Huntington, Elanor H
2014-01-01
Quantum parameter estimation is central to many fields such as quantum computation, communications and metrology. Optimal estimation theory has been instrumental in achieving the best accuracy in quantum parameter estimation, which is possible when we have very precise knowledge of and control over the model. However, uncertainties in key parameters underlying the system are unavoidable and may impact the quality of the estimate. We show here how quantum optical phase estimation of a squeezed state of light exhibits improvement when using a robust fixed-interval smoother designed with uncertainties explicitly introduced in parameters underlying the phase noise.
Sustainable Resilient, Robust & Resplendent Enterprises
DEFF Research Database (Denmark)
Edgeman, Rick
to their impact. Resplendent enterprises are introduced with resplendence referring not to some sort of public or private façade, but instead refers to organizations marked by dual brilliance and nobility of strategy, governance and comportment that yields superior and sustainable triple bottom line performance....... Herein resilience, robustness, and resplendence (R3) are integrated with sustainable enterprise excellence (Edgeman and Eskildsen, 2013) or SEE and social-ecological innovation (Eskildsen and Edgeman, 2012) to aid progress of a firm toward producing continuously relevant performance that proceed from...... continuously responsible strategy, behavior and other actions. A SEER3 model is introduced and a means of SEER3 maturity assessment is suggested....
Nan, R. D.; Zhang, H. Y.; Zhang, Y.; Yang, L.; Cai, W. J.; Liu, N.; Xie, J. T.; Zhang, S. X.
2016-11-01
The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. A unique karst depression in Guizhou province has been selected as the site to build an active reflector radio telescope with a diameter of 500 m and three outstanding aspects, which enables FAST to have a large sky coverage and the ability of observing astronomical targets with a high precision. Chinese Academy of Sciences and Guizhou province are in charge of FAST construction. The first light of the telescope was expected on September 25, 2016.
Energy Technology Data Exchange (ETDEWEB)
Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.
1980-07-01
This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.
Energy Technology Data Exchange (ETDEWEB)
NONE
1972-06-01
Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.
A computationally simple and robust method to detect determinism in a time series
DEFF Research Database (Denmark)
Lu, Sheng; Ju, Ki Hwan; Kanters, Jørgen K.;
2006-01-01
We present a new, simple, and fast computational technique, termed the incremental slope (IS), that can accurately distinguish between deterministic from stochastic systems even when the variance of noise is as large or greater than the signal, and remains robust for time-varying signals. The IS ...
Progressive refinement for robust image registration
Institute of Scientific and Technical Information of China (English)
Li Song; Yuanhua Zhou; Jun Zhou
2005-01-01
@@ A new image registration algorithm with robust cost function and progressive refinement estimation is developed on the basis of direct method (DM). The robustness lies in M-estimation to avert larger local noise and outliers.
Robust Instrumentation[Water treatment for power plant]; Robust Instrumentering
Energy Technology Data Exchange (ETDEWEB)
Wik, Anders [Vattenfall Utveckling AB, Stockholm (Sweden)
2003-08-01
Cementa Slite Power Station is a heat recovery steam generator (HRSG) with moderate steam data; 3.0 MPa and 420 deg C. The heat is recovered from Cementa, a cement industry, without any usage of auxiliary fuel. The Power station commenced operation in 2001. The layout of the plant is unusual, there are no similar in Sweden and very few world-wide, so the operational experiences are limited. In connection with the commissioning of the power plant a R and D project was identified with the objective to minimise the manpower needed for chemistry management of the plant. The lean chemistry management is based on robust instrumentation and chemical-free water treatment plant. The concept with robust instrumentation consists of the following components; choice of on-line instrumentation with a minimum of O and M and a chemical-free water treatment. The parameters are specific conductivity, cation conductivity, oxygen and pH. In addition to that, two fairly new on-line instruments were included; corrosion monitors and differential pH calculated from specific and cation conductivity. The chemical-free water treatment plant consists of softening, reverse osmosis and electro-deionisation. The operational experience shows that the cycle chemistry is not within the guidelines due to major problems with the operation of the power plant. These problems have made it impossible to reach steady state and thereby not viable to fully verify and validate the concept with robust instrumentation. From readings on the panel of the online analysers some conclusions may be drawn, e.g. the differential pH measurements have fulfilled the expectations. The other on-line analysers have been working satisfactorily apart from contamination with turbine oil, which has been noticed at least twice. The corrosion monitors seem to be working but the lack of trend curves from the mainframe computer system makes it hard to draw any clear conclusions. The chemical-free water treatment has met all
Institute of Scientific and Technical Information of China (English)
Lihua Xie
2005-01-01
The problem of state estimation for uncertain systems has attracted a recurring interest in the past decade. In this paper, we shall give an overview on some of the recent development in the area by focusing on the robust H2 (Kaiman) filtering of uncertain discrete-time systems. The robust H2 estimation is concerned with the design of a fixed estimator for a family of plants under consideration such that the estimation error covariance is of a minimal upper bound. The uncertainty under consideration includes norm-bounded uncertainty and polytopic uncertainty. In the finite horizon case, we shall discuss a parameterized difference Riccati equation approach for systems with normbounded uncertainty and pinpoint the difference of state estimation between systems without uncertainty and those with uncertainty. In the infinite horizon case, we shall deal with both the norm-bounded and polytopic uncertainties using a linear matrix inequality (LMI) approach. In particular, we shall demonstrate how the conservatism of design can be improved using a slack variable technique. We also propose an iterative algorithm to refine a designed estimator. An example will be given to compare estimators designed using various techniques.
Robust distributed cognitive relay beamforming
Pandarakkottilil, Ubaidulla
2012-05-01
In this paper, we present a distributed relay beamformer design for a cognitive radio network in which a cognitive (or secondary) transmit node communicates with a secondary receive node assisted by a set of cognitive non-regenerative relays. The secondary nodes share the spectrum with a licensed primary user (PU) node, and each node is assumed to be equipped with a single transmit/receive antenna. The interference to the PU resulting from the transmission from the cognitive nodes is kept below a specified limit. The proposed robust cognitive relay beamformer design seeks to minimize the total relay transmit power while ensuring that the transceiver signal-to-interference- plus-noise ratio and PU interference constraints are satisfied. The proposed design takes into account a parameter of the error in the channel state information (CSI) to render the performance of the beamformer robust in the presence of imperfect CSI. Though the original problem is non-convex, we show that the proposed design can be reformulated as a tractable convex optimization problem that can be solved efficiently. Numerical results are provided and illustrate the performance of the proposed designs for different network operating conditions and parameters. © 2012 IEEE.
A ROBUST OPTICAL FLOW COMPUTATION
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper presents a new method for robust and accurate optical flow estimation. The significance of this work is twofold. Firstly, the idea of bi-directional scheme is adopted to reduce the model error of optical flow equation, which allows the second order Taylor's expansion of optical flow equation for accurate solution without much extra computational burden; Secondly, this paper establishs a new optical flow equation based on LSCM (Local Structure Constancy Model) instead of BCM (Brightness Constancy Model), namely the optical flow equation does not act on scalar but on tensor-valued (matrix-valued) field, due to the two reason: (1) structure tensor-value contains local spatial structure information, which provides us more useable cues for computation than scalar; (2) local image structure is less sensitive to illumination variation than intensity, which weakens the disturbance of non-uniform illumination in real sequences. Qualitative and quantitative results for synthetic and real-world scenes show that the new method can produce an accurate and robust results.
Robust Inflation from Fibrous Strings
Burgess, C P; de Alwis, S; Quevedo, F
2016-01-01
Successful inflationary models should (i) describe the data well; (ii) arise generically from sensible UV completions; (iii) be insensitive to detailed fine-tunings of parameters and (iv) make interesting new predictions. We argue that a class of models with these properties is characterized by relatively simple potentials with a constant term and negative exponentials. We here continue earlier work exploring UV completions for these models, including the key (though often ignored) issue of modulus stabilisation, to assess the robustness of their predictions. We show that string models where the inflaton is a fibration modulus seem to be robust due to an effective rescaling symmetry, and fairly generic since most known Calabi-Yau manifolds are fibrations. This class of models is characterized by a generic relation between the tensor-to-scalar ratio $r$ and the spectral index $n_s$ of the form $r \\propto (n_s -1)^2$ where the proportionality constant depends on the nature of the effects used to develop the inf...
Robust Inflation from fibrous strings
Burgess, C. P.; Cicoli, M.; de Alwis, S.; Quevedo, F.
2016-05-01
Successful inflationary models should (i) describe the data well; (ii) arise generically from sensible UV completions; (iii) be insensitive to detailed fine-tunings of parameters and (iv) make interesting new predictions. We argue that a class of models with these properties is characterized by relatively simple potentials with a constant term and negative exponentials. We here continue earlier work exploring UV completions for these models—including the key (though often ignored) issue of modulus stabilisation—to assess the robustness of their predictions. We show that string models where the inflaton is a fibration modulus seem to be robust due to an effective rescaling symmetry, and fairly generic since most known Calabi-Yau manifolds are fibrations. This class of models is characterized by a generic relation between the tensor-to-scalar ratio r and the spectral index ns of the form r propto (ns-1)2 where the proportionality constant depends on the nature of the effects used to develop the inflationary potential and the topology of the internal space. In particular we find that the largest values of the tensor-to-scalar ratio that can be obtained by generalizing the original set-up are of order r lesssim 0.01. We contrast this general picture with specific popular models, such as the Starobinsky scenario and α-attractors. Finally, we argue the self consistency of large-field inflationary models can strongly constrain non-supersymmetric inflationary mechanisms.
Robust Inflation from fibrous strings
Energy Technology Data Exchange (ETDEWEB)
Burgess, C.P. [Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON (Canada); Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON (Canada); Cicoli, M. [Dipartimento di Fisica e Astronomia, Università di Bologna,via Irnerio 46, 40126 Bologna (Italy); INFN, Sezione di Bologna, Bologna (Italy); Abdus Salam International Center for Theoretical Physics,Strada Costiera 11, Trieste 34014 (Italy); Alwis, S. de [Physics Department, University of Colorado,Boulder, CO 80309 (United States); Quevedo, F. [Abdus Salam International Center for Theoretical Physics,Strada Costiera 11, Trieste 34014 (Italy); DAMTP, University of Cambridge,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2016-05-13
Successful inflationary models should (i) describe the data well; (ii) arise generically from sensible UV completions; (iii) be insensitive to detailed fine-tunings of parameters and (iv) make interesting new predictions. We argue that a class of models with these properties is characterized by relatively simple potentials with a constant term and negative exponentials. We here continue earlier work exploring UV completions for these models — including the key (though often ignored) issue of modulus stabilisation — to assess the robustness of their predictions. We show that string models where the inflaton is a fibration modulus seem to be robust due to an effective rescaling symmetry, and fairly generic since most known Calabi-Yau manifolds are fibrations. This class of models is characterized by a generic relation between the tensor-to-scalar ratio r and the spectral index n{sub s} of the form r∝(n{sub s}−1){sup 2} where the proportionality constant depends on the nature of the effects used to develop the inflationary potential and the topology of the internal space. In particular we find that the largest values of the tensor-to-scalar ratio that can be obtained by generalizing the original set-up are of order r≲0.01. We contrast this general picture with specific popular models, such as the Starobinsky scenario and α-attractors. Finally, we argue the self consistency of large-field inflationary models can strongly constrain non-supersymmetric inflationary mechanisms.
Institute of Scientific and Technical Information of China (English)
Li Jing; Gao Zhenghong; Huang Jiangtao; Zhao Ke
2013-01-01
A robust optimization design approach of natural laminar airfoils is developed in this paper.First,the non-uniform rational B-splines (NURBS) free form deformation method based on NURBS basis function is introduced to the airfoil parameterization.Second,aerodynamic characteristics are evaluated by solving Navier Stokes equations,and the γ-Reθt transition model coupling with shear-stress transport (SST) turbulent model is introduced to simulate boundary layer transition.A numerical simulation of transition flow around NLF0416 airfoil is conducted to test the code.The comparison between numerical simulation results and wind tunnel test data approves the validity and applicability of the present transition model.Third,the optimization system is set up,which uses the separated particle swarm optimization (SPSO) as search algorithm and combines the Kriging models as surrogate model during optimization.The system is applied to carry out robust design about the uncertainty of lift coefficient and Mach number for NASA NLF-0115 airfoil.The data of optimized airfoil aerodynamic characteristics indicates that the optimized airfoil can maintain laminar flow stably in an uncertain range and has a wider range of low drag.
Robust portfolio selection under norm uncertainty
Directory of Open Access Journals (Sweden)
Lei Wang
2016-06-01
Full Text Available Abstract In this paper, we consider the robust portfolio selection problem which has a data uncertainty described by the ( p , w $(p,w$ -norm in the objective function. We show that the robust formulation of this problem is equivalent to a linear optimization problem. Moreover, we present some numerical results concerning our robust portfolio selection problem.
Robust synchronization of uncertain chaotic systems
Institute of Scientific and Technical Information of China (English)
Li Fang; Hu Ai-Hua; Xu Zheng-Yuan
2006-01-01
This paper investigates robust unified (lag, anticipated, and complete) synchronization of two coupled chaotic systems. By introducing the concepts of positive definite symmetrical matrix and Riccati inequality and the theory of robust stability, several criteria on robust synchronization are established. Extensive numerical simulations are also used to confirm the results.
Methodology in robust and nonparametric statistics
Jurecková, Jana; Picek, Jan
2012-01-01
Introduction and SynopsisIntroductionSynopsisPreliminariesIntroductionInference in Linear ModelsRobustness ConceptsRobust and Minimax Estimation of LocationClippings from Probability and Asymptotic TheoryProblemsRobust Estimation of Location and RegressionIntroductionM-EstimatorsL-EstimatorsR-EstimatorsMinimum Distance and Pitman EstimatorsDifferentiable Statistical FunctionsProblemsAsymptotic Representations for L-Estimators
FAST joins Breakthrough programme
Banks, Michael
2016-11-01
The 180m Five-hundred-meter Aperture Spherical radio Telescope (FAST) - the world's largest single-aperture radio receiver - has become part of the Breakthrough Listen programme, which launched in July 2015 to look for intelligent life beyond Earth.
U.S. Department of Health & Human Services — CMS has developed a new quick reference statistical summary on annual CMS program and financial data. CMS Fast Facts includes summary information on total program...
Indian Academy of Sciences (India)
J. S. Zhang
2014-09-01
FAST, the Five-hundred meter Aperture Spherical radio Telescope, will become the largest operating single-dish telescope in the coming years. It has many advantages: much better sensitivity for its largest collecting area; large sky coverage due to its innovative design of the active primary surface; extremely radio quiet from its unique location, etc. In this work, I will highlight the future capabilities of FAST to discover and observe both galactic and extragalactic masers.
Energy Technology Data Exchange (ETDEWEB)
Koukoulas, Triantafillos, E-mail: triantafillos.koukoulas@npl.co.uk; Piper, Ben [Acoustics Group, National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)
2015-04-20
Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.
Energy Technology Data Exchange (ETDEWEB)
Dezoret, D.
1995-12-12
This work presents a study of a prototype of a synchrotron X-ray monochromator. The spectral qualities of this optic are sensitive to the heat loads which are particularly important on third synchrotron generation like ESRF. Indeed, powers generated by synchrotron beams can reach few kilowatts and power densities about a few tens watts per square millimeters. The mechanical deformations of the optical elements of the beamlines issue issue of the heat load can damage their spectral efficiencies. In order to compensate the deformations, wa have been studying the transposition of the adaptive astronomical optics technology to the x-ray field. First, we have considered the modifications of the spectral characteristics of a crystal induced by x-rays. We have established the specifications required to a technological realisation. Then, thermomechanical and technological studies have been required to transpose the astronomical technology to an x-ray technology. After these studies, we have begun the realisation of a prototype. This monochromator is composed by a crystal of silicon (111) bonded on a piezo-electric structure. The mechanical control is a loop system composed by a infrared light, a Shack-Hartmann CDD and wave front analyser. This system has to compensate the deformations of the crystal in the 5 kcV to 60 kcV energy range with a power density of 1 watt per square millimeters. (authors).
Directory of Open Access Journals (Sweden)
Ali Shamsa
2013-11-01
Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods: Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field of urology, we contacted them via email and asked for their professional opinions. Results: The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.
Directory of Open Access Journals (Sweden)
Ali Shamsa
2013-12-01
Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods:Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field of urology, we contacted them via email and asked for their professional opinions. Results:The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.
Peric, Ivan
2004-01-01
Several application specific microchips (ASICs) for the readout of pixel detectors have been designed, tested and described in this thesis. The first chapter gives the detailed description of the pixel-readout chip for the ATLAS pixel detector (FEI). The chip is now in operation as the innermost electronic component of the ATLAS detector. The chip for steering of DEPFET matrix (SWITCHER) is described in the second chapter. The chip is implemented in a high-voltage CMOS technology, it generates fast high voltage signals. Finally, a novel pixel readout chip for a hybrid x-ray pixel detector based on direct conversion is introduced. The chip (CIX) has joint photon counting and integrating capability.
Energy Technology Data Exchange (ETDEWEB)
Peric, I.
2004-08-01
Radiation tolerant pixel-readout chip for the ATLAS pixel detector has been designed, implemented in a deep-submicron CMOS technology and successfully tested. The chip contains readout-channels with complex analog and digital circuits. Chip for steering of the DEPFET active-pixel matrix has been implemented in a high-voltage CMOS technology. The chip contains channels which generate fast sequences of high-voltage signals. Detector containing this chip has been successfully tested. Pixel-readout test chip for an X-ray imaging pixel sensor has been designed, implemented in a CMOS technology and tested. Pixel-readout channels are able to simultaneously count the signals generated by passage of individual photons and to sum the total charge generated during exposure time. (orig.)
A Robust Feedforward Model of the Olfactory System.
Directory of Open Access Journals (Sweden)
Yilun Zhang
2016-04-01
Full Text Available Most natural odors have sparse molecular composition. This makes the principles of compressed sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has shown that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. However, the dynamical aspects of optimization slowed down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to third-order neurons (neurons in the olfactory cortex of vertebrates or Kenyon cells in the mushroom body of insects, which in the model corresponds to reconstruction. We show that should this specific relationship hold true, the reconstruction will be both fast and robust to noise, and in particular to the false activation of glomeruli. The predicted connectivity rate from glomeruli to third-order neurons can be tested experimentally.
A Robust Feedforward Model of the Olfactory System
Zhang, Yilun; Sharpee, Tatyana
Most natural odors have sparse molecular composition. This makes the principles of compressing sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has proposed that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. The dynamical aspects of optimization, however, would slow down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to Kenyon cells, which in the model corresponds to reconstruction. We show that provided this specific relationship holds true, the reconstruction will be both fast and robust to noise, and in particular to failure of glomeruli. The predicted connectivity rate from glomeruli to the Kenyon cells can be tested experimentally. This research was supported by James S. McDonnell Foundation, NSF CAREER award IIS-1254123, NSF Ideas Lab Collaborative Research IOS 1556388.
Jiao, Xiaohong; Mei, Zhisong
2010-10-01
To improve the quality of strip thickness, synchronisation control is investigated for cold rolling mills driven by dual-cylinder electro-hydraulic servo systems. Realising synchronised control in hydraulic automatic gauge control (HAGC) systems of cold rolling mills has challenges with not only the inherent nonlinearities of hydraulic servo systems and uncertainties of load variation but also measurement delay of strip thickness. Since all states are not measurable in practice, output feedback robust synchronisation control problem should be addressed for uncertain nonlinear systems with output delay. Thus, a reduced-order observer-based robust synchronous controller is presented by employing Lyapunov functional stability theory. The controller designed by incorporating the integral of the position synchronisation error of two pistons into state variables successfully guarantees asymptotic convergence to zero of both tracking errors and synchronisation error simultaneously regardless of the nonlinearities and uncertainties as well as the measurement delay. Simulation results in a model obtained from a real cold strip rolling mill demonstrate the effectiveness of the approach.
Robust PCA via Outlier Pursuit
Xu, Huan; Sanghavi, Sujay
2010-01-01
Singular Value Decomposition (and Principal Component Analysis) is one of the most widely used techniques for dimensionality reduction: successful and efficiently computable, it is nevertheless plagued by a well-known, well-documented sensitivity to outliers. Recent work has considered the setting where each point has a few arbitrarily corrupted components. Yet, in applications of SVD or PCA such as robust collaborative filtering or bioinformatics, malicious agents, defective genes, or simply corrupted or contaminated experiments may effectively yield entire points that are completely corrupted. We present an efficient convex optimization-based algorithm we call Outlier Pursuit, that under some mild assumptions on the uncorrupted points (satisfied, e.g., by the standard generative assumption in PCA problems) recovers the exact optimal low-dimensional subspace, and identifies the corrupted points. Such identification of corrupted points that do not conform to the low-dimensional approximation, is of paramount ...
Neutral Evolution of Mutational Robustness
Van Nimwegen, E; Huynen, M; Nimwegen, Erik van; Crutchfield, James P.; Huynen, Martijn
1999-01-01
We introduce and analyze a general model of a population evolving over a network of selectively neutral genotypes. We show that the population's limit distribution on the neutral network is solely determined by the network topology and given by the principal eigenvector of the network's adjacency matrix. Moreover, the average number of neutral mutant neighbors per individual is given by the matrix spectral radius. This quantifies the extent to which populations evolve mutational robustness: the insensitivity of the phenotype to mutations. Since the average neutrality is independent of evolutionary parameters---such as, mutation rate, population size, and selective advantage---one can infer global statistics of neutral network topology using simple population data available from {\\it in vitro} or {\\it in vivo} evolution. Populations evolving on neutral networks of RNA secondary structures show excellent agreement with our theoretical predictions.
Quantifying robustness of biochemical network models
Directory of Open Access Journals (Sweden)
Iglesias Pablo A
2002-12-01
Full Text Available Abstract Background Robustness of mathematical models of biochemical networks is important for validation purposes and can be used as a means of selecting between different competing models. Tools for quantifying parametric robustness are needed. Results Two techniques for describing quantitatively the robustness of an oscillatory model were presented and contrasted. Single-parameter bifurcation analysis was used to evaluate the stability robustness of the limit cycle oscillation as well as the frequency and amplitude of oscillations. A tool from control engineering – the structural singular value (SSV – was used to quantify robust stability of the limit cycle. Using SSV analysis, we find very poor robustness when the model's parameters are allowed to vary. Conclusion The results show the usefulness of incorporating SSV analysis to single parameter sensitivity analysis to quantify robustness.
IMC based robust PID controller tuning for disturbance rejection
Institute of Scientific and Technical Information of China (English)
Mohammad Shamsuzzoha
2016-01-01
It is well-known that the IMC-PID controller tuning gives fast and improved set point response but slow disturbance rejection. A modification has been proposed in IMC-PID tuning rule for the improved disturbance rejection. For the modified IMC-PID tuning rule, a method has been developed to obtain the IMC-PID setting in closed-loop mode without acquiring detailed information of the process. The proposed method is based on the closed-loop step set point experiment using a proportional only controller with gainKc0. It is the direct approach to find the PID controller setting similar to classical Ziegler-Nichols closed-loop method. Based on simulations of a wide range of first-order with delay processes, a simple correlation has been derived to obtain the modified IMC-PID controller settings from closed-loop experiment. In this method, controller gain is a function of the overshoot obtained in the closed loop set point experiment. The integral and derivative time is mainly a function of the time to reach the first peak (overshoot). Simulation has been conducted for the broad class of processes and the controllers were tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison. The PID controller settings obtained in the proposed tuning method show better performance and robustness with other two-step tuning methods for the broad class of processes. It has also been applied to temperature control loop in distillation column model. The result has been compared to the open loop tuning method where it gives robust and fast response.
Robust estimation of unbalanced mixture models on samples with outliers.
Galimzianova, Alfiia; Pernuš, Franjo; Likar, Boštjan; Špiclin, Žiga
2015-11-01
Mixture models are often used to compactly represent samples from heterogeneous sources. However, in real world, the samples generally contain an unknown fraction of outliers and the sources generate different or unbalanced numbers of observations. Such unbalanced and contaminated samples may, for instance, be obtained by high density data sensors such as imaging devices. Estimation of unbalanced mixture models from samples with outliers requires robust estimation methods. In this paper, we propose a novel robust mixture estimator incorporating trimming of the outliers based on component-wise confidence level ordering of observations. The proposed method is validated and compared to the state-of-the-art FAST-TLE method on two data sets, one consisting of synthetic samples with a varying fraction of outliers and a varying balance between mixture weights, while the other data set contained structural magnetic resonance images of the brain with tumors of varying volumes. The results on both data sets clearly indicate that the proposed method is capable to robustly estimate unbalanced mixtures over a broad range of outlier fractions. As such, it is applicable to real-world samples, in which the outlier fraction cannot be estimated in advance.
Robust Optimal Adaptive Control Method with Large Adaptive Gain
Nguyen, Nhan T.
2009-01-01
In the presence of large uncertainties, a control system needs to be able to adapt rapidly to regain performance. Fast adaptation is referred to the implementation of adaptive control with a large adaptive gain to reduce the tracking error rapidly. However, a large adaptive gain can lead to high-frequency oscillations which can adversely affect robustness of an adaptive control law. A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on the minimization of the Y2 norm of the tracking error, which is formulated as an optimal control problem. The optimality condition is used to derive the modification using the gradient method. The optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking while providing sufficient stability robustness. Simulations were conducted for a damaged generic transport aircraft with both standard adaptive control and the adaptive optimal control modification technique. The results demonstrate the effectiveness of the proposed modification in tracking a reference model while maintaining a sufficient time delay margin.
2008-04-01
IST-047 Building Robust Systems with Fallible Construction (Elaboration de systèmes informatiques robustes à l’architecture faillible) Final...IST-047 Building Robust Systems with Fallible Construction (Elaboration de systèmes informatiques robustes à l’architecture faillible...and cost investments. ES - 2 RTO-TR-IST-047 Elaboration de systèmes informatiques robustes à l’architecture faillible (RTO-TR-IST-047
Directory of Open Access Journals (Sweden)
Jenni Ylä-Mella
2014-01-01
Full Text Available Electronic devices and mobile applications have become a part of everyday life. Fast technological progress and rapid product obsolescence have led to the rapid growth of waste electrical and electronic equipment (WEEE. Due to hazardous substances and also substantial amounts of valuable materials contained in electrical and electronic equipment, the European Union has implemented Directives related to WEEE, in order to reduce negative environmental and health impacts and to improve material recovery of valuable substances from WEEE. This paper provides an overview of the WEEE Directive and its implementation to national legislations in Finland, Sweden, and Norway and, further, describes how the nationwide WEEE recovery infrastructures in the Nordic countries have been built. The Nordic WEEE management systems are evaluated from the point of resource efficiency and best practices. Evidently, the WEEE management systems as established in the Nordic countries have advantages because the WEEE collection rates in 2012 were 12 kg/inhab./year, in Finland, 16 kg/inhab./year, in Sweden, and 27 kg/ inhab./year, in Norway, despite their sparsely populated nature. The Swedish and Norwegian experiences, especially, with long history of WEEE recovery indicate that increasing consumer awareness leads to more environmentally sound behaviour and improves recovery efficiency.
Fast food prices, obesity, and the minimum wage.
Cotti, Chad; Tefft, Nathan
2013-03-01
Recent proposals argue that a fast food tax may be an effective policy lever for reducing population weight. Although there is growing evidence for a negative association between fast food prices and weight among adolescents, less is known about adults. That any measured relationship to date is causal is unclear because there has been no attempt to separate variation in prices on the demand side from that on the supply side. We argue that the minimum wage is an exogenous source of variation in fast food prices, conditional on income and employment. In two-stage least-squares analyses, we find little evidence that fast food price changes affect adult BMI or obesity prevalence. Results are robust to including controls for area and time fixed effects, area time trends, demographic characteristics, substitute prices, numbers of establishments and employment in related industries, and other potentially related factors. Copyright © 2012 Elsevier B.V. All rights reserved.
Valiant load-balanced robust routing under hose model for WDM mesh networks
Zhang, Xiaoning; Li, Lemin; Wang, Sheng
2006-09-01
In this paper, we propose Valiant Load-Balanced robust routing scheme for WDM mesh networks under the model of polyhedral uncertainty (i.e., hose model), and the proposed routing scheme is implemented with traffic grooming approach. Our Objective is to maximize the hose model throughput. A mathematic formulation of Valiant Load-Balanced robust routing is presented and three fast heuristic algorithms are also proposed. When implementing Valiant Load-Balanced robust routing scheme to WDM mesh networks, a novel traffic-grooming algorithm called MHF (minimizing hop first) is proposed. We compare the three heuristic algorithms with the VPN tree under the hose model. Finally we demonstrate in the simulation results that MHF with Valiant Load-Balanced robust routing scheme outperforms the traditional traffic-grooming algorithm in terms of the throughput for the uniform/non-uniform traffic matrix under the hose model.
Energy Technology Data Exchange (ETDEWEB)
Freeman, L.N.; Wilson, R.E. [Oregon State Univ., Dept. of Mechanical Engineering, Corvallis, OR (United States)
1996-09-01
The FAST Code which is capable of determining structural loads on a flexible, teetering, horizontal axis wind turbine is described and comparisons of calculated loads with test data are given at two wind speeds for the ESI-80. The FAST Code models a two-bladed HAWT with degrees of freedom for blade bending, teeter, drive train flexibility, yaw, and windwise and crosswind tower motion. The code allows blade dimensions, stiffnesses, and weights to differ and models tower shadow, wind shear, and turbulence. Additionally, dynamic stall is included as are delta-3 and an underslung rotor. Load comparisons are made with ESI-80 test data in the form of power spectral density, rainflow counting, occurrence histograms, and azimuth averaged bin plots. It is concluded that agreement between the FAST Code and test results is good. (au)
Institute of Scientific and Technical Information of China (English)
高怡
2010-01-01
我们都知道fast food的意思是“快餐”。那fast friend能解释为“快速或速成的朋友”吗？也许你会说：“什么是速成朋友呀？It doesn’t make sense．”没错，交朋友怎么会有速成的呢？原来；fast还有一个意思是“忠实的、牢固的”，所以a fast friend的真正意思是“可靠、忠实的朋友”。
Fast Distributed Gradient Methods
Jakovetic, Dusan; Moura, Jose M F
2011-01-01
The paper proposes new fast distributed optimization gradient methods and proves convergence to the exact solution at rate O(\\log k/k), much faster than existing distributed optimization (sub)gradient methods with convergence O(1/\\sqrt{k}), while incurring practically no additional communication nor computation cost overhead per iteration. We achieve this for convex (with at least one strongly convex,) coercive, three times differentiable and with Lipschitz continuous first derivative (private) cost functions. Our work recovers for distributed optimization similar convergence rate gains obtained by centralized Nesterov gradient and fast iterative shrinkage-thresholding algorithm (FISTA) methods over ordinary centralized gradient methods. We also present a constant step size distributed fast gradient algorithm for composite non-differentiable costs. A simulation illustrates the effectiveness of our distributed methods.
DEFF Research Database (Denmark)
Munk-Hansen, Carsten
Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder.......Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder....
DEFF Research Database (Denmark)
Edlund, Hans Henrik
1999-01-01
I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af reguleringsforpligte......I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af...
Energy Technology Data Exchange (ETDEWEB)
Malishevskii, A.S.; Silin, V.P.; Uryupin, S.A
2002-12-30
For the magnetically coupled waveguide and long Josephson junction we gave the analytic description of two separate velocity domains where the free motion of traveling vortex (2{pi}-kink) exists. The role of the mutual influence of waveguide and long Josephson junction is discussed. It is shown the possibility of the fast vortex motion with the velocity much larger than Swihart velocity of Josephson junction and close to the speed of light in the waveguide. The excitation of motion of such fast Josephson vortex is described.
Indian Academy of Sciences (India)
Karsten Köneke; on behalf of the ATLAS Collaboration
2012-11-01
The ATLAS experiment at the Large Hadron Collider is recording data from proton–proton collisions at a centre-of-mass energy of 7 TeV since the spring of 2010. The integrated luminosity has grown nearly exponentially since then and continues to rise fast. The ATLAS Collaboration has set up a framework to automatically process the rapidly growing dataset and produce performance and physics plots for the most interesting analyses. The system is designed to give fast feedback. The histograms are produced within hours of data reconstruction (2–3 days after data taking). Hints of potentially interesting physics signals obtained this way are followed up by physics groups.
Quantifying the robustness of metro networks
Wang, Xiangrong; Derrible, Sybil; Ahmad, Sk Nasir; Kooij, Robert E
2015-01-01
Metros (heavy rail transit systems) are integral parts of urban transportation systems. Failures in their operations can have serious impacts on urban mobility, and measuring their robustness is therefore critical. Moreover, as physical networks, metros can be viewed as network topological entities, and as such they possess measurable network properties. In this paper, by using network science and graph theoretical concepts, we investigate both theoretical and experimental robustness metrics (i.e., the robustness indicator, the effective graph conductance, and the critical thresholds) and their performance in quantifying the robustness of metro networks under random failures or targeted attacks. We find that the theoretical metrics quantify different aspects of the robustness of metro networks. In particular, the robustness indicator captures the number of alternative paths and the effective graph conductance focuses on the length of each path. Moreover, the high positive correlation between the theoretical m...
A network property necessary for concentration robustness
Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran
2016-10-01
Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.
Robust AIC with High Breakdown Scale Estimate
Directory of Open Access Journals (Sweden)
Shokrya Saleh
2014-01-01
Full Text Available Akaike Information Criterion (AIC based on least squares (LS regression minimizes the sum of the squared residuals; LS is sensitive to outlier observations. Alternative criterion, which is less sensitive to outlying observation, has been proposed; examples are robust AIC (RAIC, robust Mallows Cp (RCp, and robust Bayesian information criterion (RBIC. In this paper, we propose a robust AIC by replacing the scale estimate with a high breakdown point estimate of scale. The robustness of the proposed methods is studied through its influence function. We show that, the proposed robust AIC is effective in selecting accurate models in the presence of outliers and high leverage points, through simulated and real data examples.
Towards Robust Image Matching Algorithms
Parsons, Timothy J.
1984-12-01
The rapid advance in digital electronics during recent years has enabled the real-time hardware implementation of many basic image processing techniques and these methods are finding increasing use in both commercial and military applications where a superiority to existing systems can be demonstrated. The potential superiority of an entirely passive, automatic image processing based navigation system over the less accurate and active navigation systems based on radar, for example "TERCOM", is evident. By placing a sensor on board an aircraft or missile together with the appropriate processing power and enough memory to store a reference image or a map of the planned route, large scale features extracted from the scene available to the sensor can be compared with the same feature stored in memory. The difference between the aircraft's actual position and its desired position can then be evaluated and the appropriate navigational correction undertaken. This paper summaries work carried out at British Aerospace Hatfield to investigate various classes of algorithms and solutions which would render a robust image matching system viable for such an automatic system flying at low level with a thermal I.R. sensor.
Designing for Reliability and Robustness
Svetlik, Randall G.; Moore, Cherice; Williams, Antony
2017-01-01
Long duration spaceflight has a negative effect on the human body, and exercise countermeasures are used on-board the International Space Station (ISS) to minimize bone and muscle loss, combatting these effects. Given the importance of these hardware systems to the health of the crew, this equipment must continue to be readily available. Designing spaceflight exercise hardware to meet high reliability and availability standards has proven to be challenging throughout the time the crewmembers have been living on ISS beginning in 2000. Furthermore, restoring operational capability after a failure is clearly time-critical, but can be problematic given the challenges of troubleshooting the problem from 220 miles away. Several best-practices have been leveraged in seeking to maximize availability of these exercise systems, including designing for robustness, implementing diagnostic instrumentation, relying on user feedback, and providing ample maintenance and sparing. These factors have enhanced the reliability of hardware systems, and therefore have contributed to keeping the crewmembers healthy upon return to Earth. This paper will review the failure history for three spaceflight exercise countermeasure systems identifying lessons learned that can help improve future systems. Specifically, the Treadmill with Vibration Isolation and Stabilization System (TVIS), Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), and the Advanced Resistive Exercise Device (ARED) will be reviewed, analyzed, and conclusions identified so as to provide guidance for improving future exercise hardware designs. These lessons learned, paired with thorough testing, offer a path towards reduced system down-time.
Efficient robust conditional random fields.
Song, Dongjin; Liu, Wei; Zhou, Tianyi; Tao, Dacheng; Meyer, David A
2015-10-01
Conditional random fields (CRFs) are a flexible yet powerful probabilistic approach and have shown advantages for popular applications in various areas, including text analysis, bioinformatics, and computer vision. Traditional CRF models, however, are incapable of selecting relevant features as well as suppressing noise from noisy original features. Moreover, conventional optimization methods often converge slowly in solving the training procedure of CRFs, and will degrade significantly for tasks with a large number of samples and features. In this paper, we propose robust CRFs (RCRFs) to simultaneously select relevant features. An optimal gradient method (OGM) is further designed to train RCRFs efficiently. Specifically, the proposed RCRFs employ the l1 norm of the model parameters to regularize the objective used by traditional CRFs, therefore enabling discovery of the relevant unary features and pairwise features of CRFs. In each iteration of OGM, the gradient direction is determined jointly by the current gradient together with the historical gradients, and the Lipschitz constant is leveraged to specify the proper step size. We show that an OGM can tackle the RCRF model training very efficiently, achieving the optimal convergence rate [Formula: see text] (where k is the number of iterations). This convergence rate is theoretically superior to the convergence rate O(1/k) of previous first-order optimization methods. Extensive experiments performed on three practical image segmentation tasks demonstrate the efficacy of OGM in training our proposed RCRFs.
Nanotechnology Based Environmentally Robust Primers
Energy Technology Data Exchange (ETDEWEB)
Barbee, T W Jr; Gash, A E; Satcher, J H Jr; Simpson, R L
2003-03-18
An initiator device structure consisting of an energetic metallic nano-laminate foil coated with a sol-gel derived energetic nano-composite has been demonstrated. The device structure consists of a precision sputter deposition synthesized nano-laminate energetic foil of non-toxic and non-hazardous metals along with a ceramic-based energetic sol-gel produced coating made up of non-toxic and non-hazardous components such as ferric oxide and aluminum metal. Both the nano-laminate and sol-gel technologies are versatile commercially viable processes that allow the ''engineering'' of properties such as mechanical sensitivity and energy output. The nano-laminate serves as the mechanically sensitive precision igniter and the energetic sol-gel functions as a low-cost, non-toxic, non-hazardous booster in the ignition train. In contrast to other energetic nanotechnologies these materials can now be safely manufactured at application required levels, are structurally robust, have reproducible and engineerable properties, and have excellent aging characteristics.
Robust growth of Escherichia coli.
Wang, Ping; Robert, Lydia; Pelletier, James; Dang, Wei Lien; Taddei, Francois; Wright, Andrew; Jun, Suckjoon
2010-06-22
The quantitative study of the cell growth has led to many fundamental insights in our understanding of a wide range of subjects, from the cell cycle to senescence. Of particular importance is the growth rate, whose constancy represents a physiological steady state of an organism. Recent studies, however, suggest that the rate of elongation during exponential growth of bacterial cells decreases cumulatively with replicative age for both asymmetrically and symmetrically dividing organisms, implying that a "steady-state" population consists of individual cells that are never in a steady state of growth. To resolve this seeming paradoxical observation, we studied the long-term growth and division patterns of Escherichia coli cells by employing a microfluidic device designed to follow steady-state growth and division of a large number of cells at a defined reproductive age. Our analysis of approximately 10(5) individual cells reveals a remarkable stability of growth whereby the mother cell inherits the same pole for hundreds of generations. We further show that death of E. coli is not purely stochastic but is the result of accumulating damages. We conclude that E. coli, unlike all other aging model systems studied to date, has a robust mechanism of growth that is decoupled from cell death.
Nonlinear Robust Control for Spacecraft Attitude
Directory of Open Access Journals (Sweden)
Wang Lina
2013-07-01
Full Text Available Nonlinear robust control of the spacecraft attitude with the existence of external disturbances is considered. A robust attitude controller is designed based on the passivity approach the quaternion representation, which introduces the suppression vector of external disturbance into the control law and does not need angular velocity measurement. Stability conditions of the robust attitude controller are given. And the numerical simulation results show the effectiveness of the attitude controller.
Robust chaos in smooth unimodal maps
Andrecut, M.; Ali, M. K.
2001-08-01
Robust chaos is defined by the absence of periodic windows and coexisting attractors in some neighborhood of the parameter space. It has been conjectured that robust chaos cannot occur in smooth systems [E. Barreto, B. Hunt, and C. Grebogi, Phys. Rev. Lett. 78, 4561 (1997); 80, 3049 (1998)]. Contrary to this conjecture, we describe a general procedure for generating robust chaos in smooth unimodal maps.
Robustness of timber structures in seismic areas
Neves, Luís A.C.; Branco, Jorge M.
2011-01-01
Major similarities between robustness assessment and seismic design exist, and significant information can be brought from seismic design to robustness design. As will be discussed, although some methods and limitations considered in seismic design can improve robustness, the capacity of the structure to sustain limited damage without disproportionate effects is significantly more complex. In fact, seismic design can either improve or reduce the resistance of structures to unfo...
DEFF Research Database (Denmark)
Edlund, Hans Henrik
Bogen tilstræber at give et overblik over nogle af de vigtigste generelle problemområder på markedet for ejendomshandel, der jo bliver mere og mere kompliceret. Værket er opdelt i følgende hovedafsnit: Ejendomsbegrebet. Indgåelse af aftale om salg af fast ejendom. Begrænsninger i adgangen til...
DEFF Research Database (Denmark)
Marras, Stefano; Noda, Takuji; Steffensen, John Fleng
2015-01-01
, it is an open question whether such supposedly very fast swimmers do use high-speed bursts when feeding on evasive prey, in addition to using their bill for slashing prey. Here, we measured the swimming behavior of sailfish by using high-frequency accelerometry and high-speed video observations during predator...
Institute of Scientific and Technical Information of China (English)
2008-01-01
China’s fast passenger tracks network consists of four parts:express rail- way with speeds between 300km/h and 350 kin/h,passenger rail lines with speeds between 200 km/h and 250 km/h,intercity high-speed railways that run
Energy Technology Data Exchange (ETDEWEB)
Till, C.E.; Chang, Y.I.
1986-01-01
The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.
DEFF Research Database (Denmark)
Hendricks, Elbert
1998-01-01
The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU...
Parallel Fast Legendre Transform
Alves de Inda, M.; Bisseling, R.H.; Maslen, D.K.
2001-01-01
We discuss a parallel implementation of a fast algorithm for the discrete polynomial Legendre transform We give an introduction to the DriscollHealy algorithm using polynomial arithmetic and present experimental results on the eciency and accuracy of our implementation The algorithms were implemente
Energy Technology Data Exchange (ETDEWEB)
Taylor, L.H.; Mair, J.
1996-12-31
The decision by British Petroleum to develop offshore fields west of the Shetlands in water depths exceeding 500 meters within three and a half years of discovery posed a unique submarine pipeline installation challenge. This paper summarizes the salient features of a fast track program to install a diverless subsea pipeline system using rigid reeled pipe technology in an offshore frontier area.
... Order smaller servings when you can. Split some fast-food items to reduce calories and fat. Ask for a "doggy bag." You can also leave the extra food on your plate. Your food choices can teach your children how to eat healthy, too. Choosing a variety ...
Fast Fourier Orthogonalization
Ducas, L.; Prest, T.; Abramov, S.A.; Zima, E.V.; Gao, X-S.
2016-01-01
The classical fast Fourier transform (FFT) allows to compute in quasi-linear time the product of two polynomials, in the {\\em circular convolution ring} R[x]/(x^d−1) --- a task that naively requires quadratic time. Equivalently, it allows to accelerate matrix-vector products when the matrix is *circ
... SA) node --- the heart's natural pacemaker - sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly. Causes of sinus tachycardia A rapid heartbeat may be your body's response to common conditions such as: Fever Anxiety ...
FAST TEXT LOCATION BASED ON DISCRETE WAVELET TRANSFORM
Institute of Scientific and Technical Information of China (English)
Li Xiaohua; Shen Lansun
2005-01-01
The paper describes a texture-based fast text location scheme which operates directly in the Discrete Wavelet Transform (DWT) domain. By the distinguishing texture characteristics encoded in wavelet transform domain, the text is fast detected from complex background images stored in the compressed format such as JPEG2000 without full decompress. Compared with some traditional character location methods, the proposed scheme has the advantages of low computational cost, robust to size and font of characters and high accuracy. Preliminary experimental results show that the proposed scheme is efficient and effective.
An efficient and fast detection algorithm for multimode FBG sensing
DEFF Research Database (Denmark)
Ganziy, Denis; Jespersen, O.; Rose, B.
2015-01-01
We propose a novel dynamic gate algorithm (DGA) for fast and accurate peak detection. The algorithm uses threshold determined detection window and Center of gravity algorithm with bias compensation. We analyze the wavelength fit resolution of the DGA for different values of signal to noise ratio...... and different typical peak shapes. Our simulations and experiments demonstrate that the DGA method is fast and robust with higher stability and accuracy compared to conventional algorithms. This makes it very attractive for future implementation in sensing systems especially based on multimode fiber Bragg...
Biologically inspired robust onset detection
Smith, Leslie S.
2003-04-01
Onsets are rapid increases in signal strength. The common onset time in different frequency bands provides an important cue for dynamically grouping sound energy, and hence for sound streaming. Onsets are important for segmenting sounds [Smith, J. New Music Res. 23, 11-23 (1994)] and for determining where to measure IIDs and ITDs for the sound direction finding [Smith, J. Acoust. Soc. Am. 111, 2467 (2002)]. Effective onset detection requires low latency and the capacity to cope with wide variation in the dynamic range. Many neurons in the auditory brainstem are sensitive to onsets. The system filters sound into cochlea-like bands (using a Gammatone filterbank), then spike codes positive-going zero-crossings. A wide dynamic range is achieved by using multiple spike trains per filter band, each with different sensitivity. The spike trains from each band innervate a leaky integrate-and-fire neuron. The excitatory synapses from the spike trains are fast and depressing: the shunting inhibitory synapses are facilitating and slower. The combined effect is that the neuron produces a single spike for each onset over a wide dynamic range with very low latency. The use of both inhibitory and excitatory synapses improves onset detection over purely excitatory synapses, leading to a better sound direction finding than previously reported.
Adaptive line enhancers for fast acquisition
Yeh, H.-G.; Nguyen, T. M.
1994-01-01
Three adaptive line enhancer (ALE) algorithms and architectures - namely, conventional ALE, ALE with double filtering, and ALE with coherent accumulation - are investigated for fast carrier acquisition in the time domain. The advantages of these algorithms are their simplicity, flexibility, robustness, and applicability to general situations including the Earth-to-space uplink carrier acquisition and tracking of the spacecraft. In the acquisition mode, these algorithms act as bandpass filters; hence, the carrier-to-noise ratio (CNR) is improved for fast acquisition. In the tracking mode, these algorithms simply act as lowpass filters to improve signal-to-noise ratio; hence, better tracking performance is obtained. It is not necessary to have a priori knowledge of the received signal parameters, such as CNR, Doppler, and carrier sweeping rate. The implementation of these algorithms is in the time domain (as opposed to the frequency domain, such as the fast Fourier transform (FFT)). The carrier frequency estimation can be updated in real time at each time sample (as opposed to the batch processing of the FFT). The carrier frequency to be acquired can be time varying, and the noise can be non-Gaussian, nonstationary, and colored.
Noise and robustness in phyllotaxis.
Mirabet, Vincent; Besnard, Fabrice; Vernoux, Teva; Boudaoud, Arezki
2012-01-01
A striking feature of vascular plants is the regular arrangement of lateral organs on the stem, known as phyllotaxis. The most common phyllotactic patterns can be described using spirals, numbers from the Fibonacci sequence and the golden angle. This rich mathematical structure, along with the experimental reproduction of phyllotactic spirals in physical systems, has led to a view of phyllotaxis focusing on regularity. However all organisms are affected by natural stochastic variability, raising questions about the effect of this variability on phyllotaxis and the achievement of such regular patterns. Here we address these questions theoretically using a dynamical system of interacting sources of inhibitory field. Previous work has shown that phyllotaxis can emerge deterministically from the self-organization of such sources and that inhibition is primarily mediated by the depletion of the plant hormone auxin through polarized transport. We incorporated stochasticity in the model and found three main classes of defects in spiral phyllotaxis--the reversal of the handedness of spirals, the concomitant initiation of organs and the occurrence of distichous angles--and we investigated whether a secondary inhibitory field filters out defects. Our results are consistent with available experimental data and yield a prediction of the main source of stochasticity during organogenesis. Our model can be related to cellular parameters and thus provides a framework for the analysis of phyllotactic mutants at both cellular and tissular levels. We propose that secondary fields associated with organogenesis, such as other biochemical signals or mechanical forces, are important for the robustness of phyllotaxis. More generally, our work sheds light on how a target pattern can be achieved within a noisy background.
Noise and robustness in phyllotaxis.
Directory of Open Access Journals (Sweden)
Vincent Mirabet
Full Text Available A striking feature of vascular plants is the regular arrangement of lateral organs on the stem, known as phyllotaxis. The most common phyllotactic patterns can be described using spirals, numbers from the Fibonacci sequence and the golden angle. This rich mathematical structure, along with the experimental reproduction of phyllotactic spirals in physical systems, has led to a view of phyllotaxis focusing on regularity. However all organisms are affected by natural stochastic variability, raising questions about the effect of this variability on phyllotaxis and the achievement of such regular patterns. Here we address these questions theoretically using a dynamical system of interacting sources of inhibitory field. Previous work has shown that phyllotaxis can emerge deterministically from the self-organization of such sources and that inhibition is primarily mediated by the depletion of the plant hormone auxin through polarized transport. We incorporated stochasticity in the model and found three main classes of defects in spiral phyllotaxis--the reversal of the handedness of spirals, the concomitant initiation of organs and the occurrence of distichous angles--and we investigated whether a secondary inhibitory field filters out defects. Our results are consistent with available experimental data and yield a prediction of the main source of stochasticity during organogenesis. Our model can be related to cellular parameters and thus provides a framework for the analysis of phyllotactic mutants at both cellular and tissular levels. We propose that secondary fields associated with organogenesis, such as other biochemical signals or mechanical forces, are important for the robustness of phyllotaxis. More generally, our work sheds light on how a target pattern can be achieved within a noisy background.
Noise and Robustness in Phyllotaxis
Mirabet, Vincent; Besnard, Fabrice; Vernoux, Teva; Boudaoud, Arezki
2012-01-01
A striking feature of vascular plants is the regular arrangement of lateral organs on the stem, known as phyllotaxis. The most common phyllotactic patterns can be described using spirals, numbers from the Fibonacci sequence and the golden angle. This rich mathematical structure, along with the experimental reproduction of phyllotactic spirals in physical systems, has led to a view of phyllotaxis focusing on regularity. However all organisms are affected by natural stochastic variability, raising questions about the effect of this variability on phyllotaxis and the achievement of such regular patterns. Here we address these questions theoretically using a dynamical system of interacting sources of inhibitory field. Previous work has shown that phyllotaxis can emerge deterministically from the self-organization of such sources and that inhibition is primarily mediated by the depletion of the plant hormone auxin through polarized transport. We incorporated stochasticity in the model and found three main classes of defects in spiral phyllotaxis – the reversal of the handedness of spirals, the concomitant initiation of organs and the occurrence of distichous angles – and we investigated whether a secondary inhibitory field filters out defects. Our results are consistent with available experimental data and yield a prediction of the main source of stochasticity during organogenesis. Our model can be related to cellular parameters and thus provides a framework for the analysis of phyllotactic mutants at both cellular and tissular levels. We propose that secondary fields associated with organogenesis, such as other biochemical signals or mechanical forces, are important for the robustness of phyllotaxis. More generally, our work sheds light on how a target pattern can be achieved within a noisy background. PMID:22359496
Robust GPS carrier tracking under ionospheric scintillation
Susi, M.; Andreotti, M.; Aquino, M. H.; Dodson, A.
2013-12-01
Small scale irregularities present in the ionosphere can induce fast and unpredictable fluctuations of Radio Frequency (RF) signal phase and amplitude. This phenomenon, known as scintillation, can degrade the performance of a GPS receiver leading to cycle slips, increasing the tracking error and also producing a complete loss of lock. In the most severe scenarios, if the tracking of multiple satellites links is prevented, outages in the GPS service can also occur. In order to render a GPS receiver more robust under scintillation, particular attention should be dedicated to the design of the carrier tracking stage, that is the receiver's part most sensitive to these types of phenomenon. This paper exploits the reconfigurability and flexibility of a GPS software receiver to develop a tracking algorithm that is more robust under ionospheric scintillation. For this purpose, first of all, the scintillation level is monitored in real time. Indeed the carrier phase and the post correlation terms obtained by the PLL (Phase Locked Loop) are used to estimate phi60 and S4 [1], the scintillation indices traditionally used to quantify the level of phase and amplitude scintillations, as well as p and T, the spectral parameters of the fluctuations PSD. The effectiveness of the scintillation parameter computation is confirmed by comparing the values obtained by the software receiver and the ones provided by a commercial scintillation monitoring, i.e. the Septentrio PolarxS receiver [2]. Then the above scintillation parameters and the signal carrier to noise density are exploited to tune the carrier tracking algorithm. In case of very weak signals the FLL (Frequency Locked Loop) scheme is selected in order to maintain the signal lock. Otherwise an adaptive bandwidth Phase Locked Loop (PLL) scheme is adopted. The optimum bandwidth for the specific scintillation scenario is evaluated in real time by exploiting the Conker formula [1] for the tracking jitter estimation. The performance
Not so fast: hippocampal amnesia slows word learning despite successful fast mapping.
Warren, David E; Duff, Melissa C
2014-08-01
The human hippocampus is widely believed to be necessary for the rapid acquisition of new declarative relational memories. However, processes supporting on-line inferential word use ("fast mapping") may also exercise a dissociable learning mechanism and permit rapid word learning without the hippocampus (Sharon et al. (2011) Proc Natl Acad Sci USA 108:1146-1151). We investigated fast mapping in severely amnesic patients with hippocampal damage (N = 4), mildly amnesic patients (N = 6), and healthy comparison participants (N = 10) using on-line measures (eye movements) that reflected ongoing processing. All participants studied unique word-picture associations in two encoding conditions. In the explicit-encoding condition, uncommon items were paired with their names (e.g., "This is a numbat."). In the fast mapping study condition, participants heard an instruction using a novel word (e.g., "Click on the numbat.") while two items were presented (an uncommon target such as a numbat, and a common distracter such as a dog). All groups performed fast mapping well at study, and on-line eye movement measures did not reveal group differences. However, while comparison participants showed robust word learning irrespective of encoding condition, severely amnesic patients showed no evidence of learning after fast mapping or explicit encoding on any behavioral or eye-movement measure. Mildly amnesic patients showed some learning, but performance was unaffected by encoding condition. The findings are consistent with the following propositions: the hippocampus is not essential for on-line fast mapping of novel words; but is necessary for the rapid learning of arbitrary relational information irrespective of encoding conditions.
Efficient and robust analysis of complex scattering data under noise in microwave resonators
Probst, S.; Song, F. B.; Bushev, P. A.; Ustinov, A. V.; Weides, M.
2015-02-01
Superconducting microwave resonators are reliable circuits widely used for detection and as test devices for material research. A reliable determination of their external and internal quality factors is crucial for many modern applications, which either require fast measurements or operate in the single photon regime with small signal to noise ratios. Here, we use the circle fit technique with diameter correction and provide a step by step guide for implementing an algorithm for robust fitting and calibration of complex resonator scattering data in the presence of noise. The speedup and robustness of the analysis are achieved by employing an algebraic rather than an iterative fit technique for the resonance circle.
Efficient and robust analysis of complex scattering data under noise in microwave resonators
Energy Technology Data Exchange (ETDEWEB)
Probst, S., E-mail: sebastian.probst@kit.edu [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Song, F. B. [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); The 10th Institute of Chinese Electronic Technology Corporation, Chengdu 610036 (China); Bushev, P. A. [Experimentalphysik, Universität des Saarlandes, D-66123 Saarbrücken (Germany); Ustinov, A. V. [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Laboratory of Superconducting Metamaterials, National University of Science and Technology “MISIS,” Moscow 119049 (Russian Federation); Weides, M. [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Institut für Physik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany)
2015-02-15
Superconducting microwave resonators are reliable circuits widely used for detection and as test devices for material research. A reliable determination of their external and internal quality factors is crucial for many modern applications, which either require fast measurements or operate in the single photon regime with small signal to noise ratios. Here, we use the circle fit technique with diameter correction and provide a step by step guide for implementing an algorithm for robust fitting and calibration of complex resonator scattering data in the presence of noise. The speedup and robustness of the analysis are achieved by employing an algebraic rather than an iterative fit technique for the resonance circle.
Security and robustness for collaborative monitors
Testerink, Bas; Bulling, Nils; Dastani, Mehdi
2016-01-01
Decentralized monitors can be subject to robustness and security risks. Robustness risks include attacks on the monitor’s infrastructure in order to disable parts of its functionality. Security risks include attacks that try to extract information from the monitor and thereby possibly leak sensitive
Robustness of Long Span Reciprocal Timber Structures
DEFF Research Database (Denmark)
Balfroid, Nathalie; Kirkegaard, Poul Henning; Sassone, Mario SASSONE
2011-01-01
engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper makes a discussion of such robustness issues related to the future development of reciprocal timber structures. The paper concludes that these kind of structures can have...
Robust fabric substrates for photonic textile applications
Van Pieterson, L.; Bouten, P.C.P.; Kriege, J.C.; Bhattacharya, R.
2010-01-01
A fabric substrate is described for electronic textile with robust interwoven connections between the conductive yarns in it. The fabric's robustness, as a function of the electrical reliability of its conductive yarn connections, is shown to hold over large deformations.This fabric is then used to
Robust fabric substrates for photonic textile applications
Van Pieterson, L.; Bouten, P.C.P.; Kriege, J.C.; Bhattacharya, R.
2010-01-01
A fabric substrate is described for electronic textile with robust interwoven connections between the conductive yarns in it. The fabric's robustness, as a function of the electrical reliability of its conductive yarn connections, is shown to hold over large deformations.This fabric is then used to
Robust identification for rational fractional transfer functions
Institute of Scientific and Technical Information of China (English)
王书宁
1997-01-01
An algorithm is proposed for robust identification of a rational fractional transfer function with a fixed degree under the framework of worst-case/deterministic robust identification. The convergence of the algorithm is proven. Its feasibility is shown with a numerical example.
Adaptively robust filtering with classified adaptive factors
Institute of Scientific and Technical Information of China (English)
CUI Xianqiang; YANG Yuanxi
2006-01-01
The key problems in applying the adaptively robust filtering to navigation are to establish an equivalent weight matrix for the measurements and a suitable adaptive factor for balancing the contributions of the measurements and the predicted state information to the state parameter estimates. In this paper, an adaptively robust filtering with classified adaptive factors was proposed, based on the principles of the adaptively robust filtering and bi-factor robust estimation for correlated observations. According to the constant velocity model of Kalman filtering, the state parameter vector was divided into two groups, namely position and velocity. The estimator of the adaptively robust filtering with classified adaptive factors was derived, and the calculation expressions of the classified adaptive factors were presented. Test results show that the adaptively robust filtering with classified adaptive factors is not only robust in controlling the measurement outliers and the kinematic state disturbing but also reasonable in balancing the contributions of the predicted position and velocity, respectively, and its filtering accuracy is superior to the adaptively robust filter with single adaptive factor based on the discrepancy of the predicted position or the predicted velocity.
An Implementation Technique for Multivariate Robust Design
Institute of Scientific and Technical Information of China (English)
MA Yi-zhong; ZHAO Feng-yu
2005-01-01
This paper investigates systematically the problem of multivariate robust parameter design. First, a measurement criterion for the total variation of multivariate quality characteristics is introduced by the result of information theory. Then the implementation procedure in the robust design is presented. After that, a simulation example from a practical industrial process is provided. Finally, some comments and further work are discussed.
Robust dissipativity for uncertain impulsive dynamical systems
Directory of Open Access Journals (Sweden)
Liu Bin
2003-01-01
Full Text Available We discuss the robust dissipativity with respect to the quadratic supply rate for uncertain impulsive dynamical systems. By employing the Hamilton-Jacobi inequality approach, some sufficient conditions of robust dissipativity for this kind of system are established. Finally, we specialize the obtained results to the case of uncertain linear impulsive dynamical systems.