Spaces of homotopy self-equivalences a survey

CERN Document Server

Rutter, John W

1997-01-01

This survey covers groups of homotopy self-equivalence classes of topological spaces, and the homotopy type of spaces of homotopy self-equivalences. For manifolds, the full group of equivalences and the mapping class group are compared, as are the corresponding spaces. Included are methods of calculation, numerous calculations, finite generation results, Whitehead torsion and other areas. Some 330 references are given. The book assumes familiarity with cell complexes, homology and homotopy. Graduate students and established researchers can use it for learning, for reference, and to determine the current state of knowledge.

Dynamics in the Parameter Space of a Neuron Model

Science.gov (United States)

Paulo, C. Rech

2012-06-01

Some two-dimensional parameter-space diagrams are numerically obtained by considering the largest Lyapunov exponent for a four-dimensional thirteen-parameter Hindmarsh—Rose neuron model. Several different parameter planes are considered, and it is shown that depending on the combination of parameters, a typical scenario can be preserved: for some choice of two parameters, the parameter plane presents a comb-shaped chaotic region embedded in a large periodic region. It is also shown that there exist regions close to these comb-shaped chaotic regions, separated by the comb teeth, organizing themselves in period-adding bifurcation cascades.

Parameter and State Estimator for State Space Models

Directory of Open Access Journals (Sweden)

Ruifeng Ding

2014-01-01

Full Text Available This paper proposes a parameter and state estimator for canonical state space systems from measured input-output data. The key is to solve the system state from the state equation and to substitute it into the output equation, eliminating the state variables, and the resulting equation contains only the system inputs and outputs, and to derive a least squares parameter identification algorithm. Furthermore, the system states are computed from the estimated parameters and the input-output data. Convergence analysis using the martingale convergence theorem indicates that the parameter estimates converge to their true values. Finally, an illustrative example is provided to show that the proposed algorithm is effective.

Fisher matrix forecast on cosmological parameters from the dark energy survey 2-point angular correlation function

Energy Technology Data Exchange (ETDEWEB)

Sobreira, F.; Rosenfeld, R. [Universidade Estadual Paulista Julio de Mesquita Filho (IFT/UNESP), Sao Paulo, SP (Brazil). Inst. Fisica Teorica; Simoni, F. de; Costa, L.A.N. da; Gaia, M.A.G.; Ramos, B.; Ogando, R.; Makler, M. [Laboratorio Interinstitucional de e-Astronomia (LIneA), Rio de Janeiro, RJ (Brazil)

2011-07-01

Full text: We study the cosmological constraints expected for the upcoming project Dark Energy Survey (DES) with the full functional form of the 2-point angular correlation function. The angular correlation function model applied in this work includes the effects of linear redshift-space distortion, photometric redshift errors (assumed to be Gaussian) and non-linearities prevenient from gravitational infall. The Fisher information matrix is constructed with the full covariance matrix, which takes the correlation between nearby redshift shells in a proper manner. The survey was sliced into 20 redshift shells in the range 0:4 {<=} z {<=} 1:40 with a variable angular scale in order to search only the scale around the signal from the baryon acoustic oscillation, therefore well within the validity of the non-linear model employed. We found that under those assumptions and with a flat {Lambda}CDM WMAP7 fiducial model, the DES will be able to constrain the dark energy equation of state parameter w with a precision of {approx} 20% and the cold dark matter with {approx} 11% when marginalizing over the other 25 parameters (bias is treated as a free parameter for each shell). When applying WMAP7 priors on {Omega}{sub baryon}, {Omega} c{sub dm}, n{sub s}, and HST priors on the Hubble parameter, w is constrained with {approx} 9% precision. This shows that the full shape of the angular correlation function with DES data will be a powerful probe to constrain cosmological parameters. (author)

Determination of Geometric Parameters of Space Steel Constructions

Directory of Open Access Journals (Sweden)

Jitka Suchá

2005-06-01

Full Text Available The paper contains conclusions of the PhD thesis „Accuracy of determination of geometric parameters of space steel construction using geodetic methods“. Generally it is a difficult task with high requirements for the accuracy and reliability of results, i.e. space coordinates of assessed points on a steel construction. A solution of this task is complicated by the effects of atmospheric influences to begin with the temperature, which strongly affects steel constructions. It is desirable to eliminate the influence of the temperature for the evaluation of the geometric parameters. A choice of an efficient geodetic method, which fulfils demanding requirements, is often affected with a constrained place in an immediate neighbourhood of the measured construction. These conditions disable the choice of efficient points configuration of a geodetic micro network, e.g. the for forward intersection. In addition, points of a construction are often hardly accessible and therefore marking is difficult. The space polar method appears efficient owing to the mentioned reasons and its advantages were increased with the implementation of self-adhesive reflex targets for the distance measurement which enable the ermanent marking of measured points already in the course of placing the construction.

TESTS AND METHODOLOGIES FOR THE SURVEY OF NARROW SPACES

Directory of Open Access Journals (Sweden)

L. Perfetti

2017-02-01

Full Text Available The research illustrated in this article aimed at identifying a good standard methodology to survey very narrow spaces during 3D investigation of Cultural Heritage. It is an important topic in today’s era of BIM modelling applied to Cultural Heritage. Spaces like staircases, corridors and passages are very common in the architectural or archaeological fields, and obtaining a 3D-oriented survey of those areas can be a very complex task when completeness of the model and high precision are requested. Photogrammetry appears to be the most promising solution in terms of versatility and manoeuvrability also considering the quality of the required data. Fisheye lenses were studied and tested in depth because of their significant advantage in the field of view if compared with rectilinear lenses. This advantage alone can be crucial to reduce the total amount of photos and, as a consequence, to obtain manageable data, to simplify the survey phase and to significantly reduce the elaboration time. In order to overcome the main issue that arise when using fisheye lenses, which is the lack of rules that can be employed to design the survey, a general mathematical formulation to precisely estimate the GSD (Ground Sampling Distance for every optical projection is presented here. A complete survey of a real complex case study was performed in order to test and stress the proposed methodology, and to handle a fisheye-based survey from beginning to end: the photogrammetric survey of the Minguzzi Staircase. It is a complex service spiral-staircase located in the Duomo di Milano with a total height of 25 meters and characterized by a narrow walkable space about 70 centimetres wide.

Exploration of DGVM Parameter Solution Space Using Simulated Annealing: Implications for Forecast Uncertainties

Science.gov (United States)

Wells, J. R.; Kim, J. B.

2011-12-01

Parameters in dynamic global vegetation models (DGVMs) are thought to be weakly constrained and can be a significant source of errors and uncertainties. DGVMs use between 5 and 26 plant functional types (PFTs) to represent the average plant life form in each simulated plot, and each PFT typically has a dozen or more parameters that define the way it uses resource and responds to the simulated growing environment. Sensitivity analysis explores how varying parameters affects the output, but does not do a full exploration of the parameter solution space. The solution space for DGVM parameter values are thought to be complex and non-linear; and multiple sets of acceptable parameters may exist. In published studies, PFT parameters are estimated from published literature, and often a parameter value is estimated from a single published value. Further, the parameters are "tuned" using somewhat arbitrary, "trial-and-error" methods. BIOMAP is a new DGVM created by fusing MAPSS biogeography model with Biome-BGC. It represents the vegetation of North America using 26 PFTs. We are using simulated annealing, a global search method, to systematically and objectively explore the solution space for the BIOMAP PFTs and system parameters important for plant water use. We defined the boundaries of the solution space by obtaining maximum and minimum values from published literature, and where those were not available, using +/-20% of current values. We used stratified random sampling to select a set of grid cells representing the vegetation of the conterminous USA. Simulated annealing algorithm is applied to the parameters for spin-up and a transient run during the historical period 1961-1990. A set of parameter values is considered acceptable if the associated simulation run produces a modern potential vegetation distribution map that is as accurate as one produced by trial-and-error calibration. We expect to confirm that the solution space is non-linear and complex, and that

HL-LHC parameter space and scenarios

International Nuclear Information System (INIS)

Bruning, O.S.

2012-01-01

The HL-LHC project aims at a total integrated luminosity of approximately 3000 fb -1 over the lifetime of the HL-LHC. Assuming an exploitation period of ca. 10 years this goal implies an annual integrated luminosity of approximately 200 fb -1 to 300 fb -1 per year. This paper looks at potential beam parameters that are compatible with the HL-LHC performance goals and discusses briefly potential variation in the parameter space. It is shown that the design goal of the HL-LHC project can only be achieved with a full upgrade of the injector complex and the operation with β* values close to 0.15 m. Significant margins for leveling can be achieved for β* values close to 0.15 m. However, these margins can only be harvested during the HL-LHC operation if the required leveling techniques have been demonstrated in operation

Robustness of Adaptive Survey Designs to Inaccuracy of Design Parameters

Directory of Open Access Journals (Sweden)

Burger Joep

2017-09-01

Full Text Available Adaptive survey designs (ASDs optimize design features, given 1 the interactions between the design features and characteristics of sampling units and 2 a set of constraints, such as a budget and a minimum number of respondents. Estimation of the interactions is subject to both random and systematic error. In this article, we propose and evaluate four viewpoints to assess robustness of ASDs to inaccuracy of design parameter estimates: the effect of both imprecision and bias on both ASD structure and ASD performance. We additionally propose three distance measures to compare the structure of ASDs. The methodology is illustrated using a simple simulation study and a more complex but realistic case study on the Dutch Travel Survey. The proposed methodology can be applied to other ASD optimization problems. In our simulation study and case study, the ASD was fairly robust to imprecision, but not to realistic dynamics in the design parameters. To deal with the sensitivity of ASDs to changing design parameters, we recommend to learn and update the design parameters.

An open-source job management framework for parameter-space exploration: OACIS

Science.gov (United States)

Murase, Y.; Uchitane, T.; Ito, N.

2017-11-01

We present an open-source software framework for parameter-space exporation, named OACIS, which is useful to manage vast amount of simulation jobs and results in a systematic way. Recent development of high-performance computers enabled us to explore parameter spaces comprehensively, however, in such cases, manual management of the workflow is practically impossible. OACIS is developed aiming at reducing the cost of these repetitive tasks when conducting simulations by automating job submissions and data management. In this article, an overview of OACIS as well as a getting started guide are presented.

Physics parameter space of tokamak ignition devices

International Nuclear Information System (INIS)

Selcow, E.C.; Peng, Y.K.M.; Uckan, N.A.; Houlberg, W.A.

1985-01-01

This paper describes the results of a study to explore the physics parameter space of tokamak ignition experiments. A new physics systems code has been developed to perform the study. This code performs a global plasma analysis using steady-state, two-fluid, energy-transport models. In this paper, we discuss the models used in the code and their application to the analysis of compact ignition experiments. 8 refs., 8 figs., 1 tab

Survey on nonlocal games and operator space theory

Energy Technology Data Exchange (ETDEWEB)

Palazuelos, Carlos, E-mail: cpalazue@mat.ucm.es [Instituto de Ciencias Matemáticas (ICMAT), Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, Madrid (Spain); Vidick, Thomas, E-mail: vidick@cms.caltech.edu [Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, California 91125 (United States)

2016-01-15

This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states.

Survey on nonlocal games and operator space theory

International Nuclear Information System (INIS)

Palazuelos, Carlos; Vidick, Thomas

2016-01-01

This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states

Artificial intelligence applications in space and SDI: A survey

Science.gov (United States)

Fiala, Harvey E.

1988-01-01

The purpose of this paper is to survey existing and planned Artificial Intelligence (AI) applications to show that they are sufficiently advanced for 32 percent of all space applications and SDI (Space Defense Initiative) software to be AI-based software. To best define the needs that AI can fill in space and SDI programs, this paper enumerates primary areas of research and lists generic application areas. Current and planned NASA and military space projects in AI will be reviewed. This review will be largely in the selected area of expert systems. Finally, direct applications of AI to SDI will be treated. The conclusion covers the importance of AI to space and SDI applications, and conversely, their importance to AI.

On the Consistency of Bootstrap Testing for a Parameter on the Boundary of the Parameter Space

DEFF Research Database (Denmark)

Cavaliere, Giuseppe; Nielsen, Heino Bohn; Rahbek, Anders

2017-01-01

It is well known that with a parameter on the boundary of the parameter space, such as in the classic cases of testing for a zero location parameter or no autoregressive conditional heteroskedasticity (ARCH) effects, the classic nonparametric bootstrap – based on unrestricted parameter estimates...... – leads to inconsistent testing. In contrast, we show here that for the two aforementioned cases, a nonparametric bootstrap test based on parameter estimates obtained under the null – referred to as ‘restricted bootstrap’ – is indeed consistent. While the restricted bootstrap is simple to implement...... in practice, novel theoretical arguments are required in order to establish consistency. In particular, since the bootstrap is analysed both under the null hypothesis and under the alternative, non-standard asymptotic expansions are required to deal with parameters on the boundary. Detailed proofs...

Research on Geometric Positioning Algorithm of License Plate in Multidimensional Parameter Space

Directory of Open Access Journals (Sweden)

Yinhua Huan

2014-05-01

Full Text Available Considering features of vehicle license plate location method which commonly used, in order to search a consistent location for reference images with license plates feature in multidimensional parameter space, a new algorithm of geometric location is proposed. Geometric location algorithm main include model training and real time search. Which not only adapt the gray-scale linearity and the gray non-linear changes, but also support changes of scale and angle. Compared with the mainstream locating software, numerical results shows under the same test conditions that the position deviation of geometric positioning algorithm is less than 0.5 pixel. Without taking into account the multidimensional parameter space, Geometric positioning algorithm position deviation is less than 1.0 pixel and angle deviation is less than 1.0 degree taking into account the multidimensional parameter space. This algorithm is robust, simple, practical and is better than the traditional method.

Improving fault image by determination of optimum seismic survey parameters using ray-based modeling

Science.gov (United States)

Saffarzadeh, Sadegh; Javaherian, Abdolrahim; Hasani, Hossein; Talebi, Mohammad Ali

2018-06-01

In complex structures such as faults, salt domes and reefs, specifying the survey parameters is more challenging and critical owing to the complicated wave field behavior involved in such structures. In the petroleum industry, detecting faults has become crucial for reservoir potential where faults can act as traps for hydrocarbon. In this regard, seismic survey modeling is employed to construct a model close to the real structure, and obtain very realistic synthetic seismic data. Seismic modeling software, the velocity model and parameters pre-determined by conventional methods enable a seismic survey designer to run a shot-by-shot virtual survey operation. A reliable velocity model of structures can be constructed by integrating the 2D seismic data, geological reports and the well information. The effects of various survey designs can be investigated by the analysis of illumination maps and flower plots. Also, seismic processing of the synthetic data output can describe the target image using different survey parameters. Therefore, seismic modeling is one of the most economical ways to establish and test the optimum acquisition parameters to obtain the best image when dealing with complex geological structures. The primary objective of this study is to design a proper 3D seismic survey orientation to achieve fault zone structures through ray-tracing seismic modeling. The results prove that a seismic survey designer can enhance the image of fault planes in a seismic section by utilizing the proposed modeling and processing approach.

Geometry on the parameter space of the belief propagation algorithm on Bayesian networks

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Yodai [National Institute of Informatics, Research Organization of Information and Systems, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430 (Japan); Laboratory for Mathematical Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan)

2006-01-30

This Letter considers a geometrical structure on the parameter space of the belief propagation algorithm on Bayesian networks. The statistical manifold of posterior distributions is introduced, and the expression for the information metric on the manifold is derived. The expression is used to construct a cost function which can be regarded as a measure of the distance in the parameter space.

Reconciling Planck with the local value of H0 in extended parameter space

Directory of Open Access Journals (Sweden)

Eleonora Di Valentino

2016-10-01

Full Text Available The recent determination of the local value of the Hubble constant by Riess et al., 2016 (hereafter R16 is now 3.3 sigma higher than the value derived from the most recent CMB anisotropy data provided by the Planck satellite in a ΛCDM model. Here we perform a combined analysis of the Planck and R16 results in an extended parameter space, varying simultaneously 12 cosmological parameters instead of the usual 6. We find that a phantom-like dark energy component, with effective equation of state w=−1.29−0.12+0.15 at 68% c.l. can solve the current tension between the Planck dataset and the R16 prior in an extended ΛCDM scenario. On the other hand, the neutrino effective number is fully compatible with standard expectations. This result is confirmed when including cosmic shear data from the CFHTLenS survey and CMB lensing constraints from Planck. However, when BAO measurements are included we find that some of the tension with R16 remains, as also is the case when we include the supernova type Ia luminosity distances from the JLA catalog.

Neutrino masses and cosmological parameters from a Euclid-like survey: Markov Chain Monte Carlo forecasts including theoretical errors

CERN Document Server

Audren, Benjamin; Bird, Simeon; Haehnelt, Martin G.; Viel, Matteo

2013-01-01

We present forecasts for the accuracy of determining the parameters of a minimal cosmological model and the total neutrino mass based on combined mock data for a future Euclid-like galaxy survey and Planck. We consider two different galaxy surveys: a spectroscopic redshift survey and a cosmic shear survey. We make use of the Monte Carlo Markov Chains (MCMC) technique and assume two sets of theoretical errors. The first error is meant to account for uncertainties in the modelling of the effect of neutrinos on the non-linear galaxy power spectrum and we assume this error to be fully correlated in Fourier space. The second error is meant to parametrize the overall residual uncertainties in modelling the non-linear galaxy power spectrum at small scales, and is conservatively assumed to be uncorrelated and to increase with the ratio of a given scale to the scale of non-linearity. It hence increases with wavenumber and decreases with redshift. With these two assumptions for the errors and assuming further conservat...

Parameter choice in Banach space regularization under variational inequalities

International Nuclear Information System (INIS)

Hofmann, Bernd; Mathé, Peter

2012-01-01

The authors study parameter choice strategies for the Tikhonov regularization of nonlinear ill-posed problems in Banach spaces. The effectiveness of any parameter choice for obtaining convergence rates depends on the interplay of the solution smoothness and the nonlinearity structure, and it can be expressed concisely in terms of variational inequalities. Such inequalities are link conditions between the penalty term, the norm misfit and the corresponding error measure. The parameter choices under consideration include an a priori choice, the discrepancy principle as well as the Lepskii principle. For the convenience of the reader, the authors review in an appendix a few instances where the validity of a variational inequality can be established. (paper)

Fisheye Photogrammetry: Tests and Methodologies for the Survey of Narrow Spaces

Science.gov (United States)

Perfetti, L.; Polari, C.; Fassi, F.

2017-02-01

The research illustrated in this article aimed at identifying a good standard methodology to survey very narrow spaces during 3D investigation of Cultural Heritage. It is an important topic in today's era of BIM modelling applied to Cultural Heritage. Spaces like staircases, corridors and passages are very common in the architectural or archaeological fields, and obtaining a 3D-oriented survey of those areas can be a very complex task when completeness of the model and high precision are requested. Photogrammetry appears to be the most promising solution in terms of versatility and manoeuvrability also considering the quality of the required data. Fisheye lenses were studied and tested in depth because of their significant advantage in the field of view if compared with rectilinear lenses. This advantage alone can be crucial to reduce the total amount of photos and, as a consequence, to obtain manageable data, to simplify the survey phase and to significantly reduce the elaboration time. In order to overcome the main issue that arise when using fisheye lenses, which is the lack of rules that can be employed to design the survey, a general mathematical formulation to precisely estimate the GSD (Ground Sampling Distance) for every optical projection is presented here. A complete survey of a real complex case study was performed in order to test and stress the proposed methodology, and to handle a fisheye-based survey from beginning to end: the photogrammetric survey of the Minguzzi Staircase. It is a complex service spiral-staircase located in the Duomo di Milano with a total height of 25 meters and characterized by a narrow walkable space about 70 centimetres wide.

Automated entry technologies for confined space work activities: A survey.

Science.gov (United States)

Botti, Lucia; Ferrari, Emilio; Mora, Cristina

2017-04-01

Work in confined spaces poses a significant risk to workers and rescuers involved in the emergency response when an accident occurs. Despite several standards and regulations define the safety requirements for such activities, injuries, and fatalities still occur. Furthermore, the on-site inspections after accidents often reveal that both employers and employees fail to implement safe entry procedures. Removing the risk is possible by avoiding the worker entry, but many activities require the presence of the operator inside the confined space to perform manual tasks. The following study investigates the available technologies for hazardous confined space work activities, e.g., cleaning, inspecting, and maintenance tasks. The aim is to provide a systematic review of the automated solutions for high-risk activities in confined spaces, considering the non-man entry as the most effective confined space safety strategy. Second, this survey aims to provide suggestions for future research addressing the design of new technologies. The survey consists of about 60 papers concerning innovative technologies for confined space work activities. The document review shows that several solutions have been developed and automation can replace the workers for a limited number of hazardous tasks. Several activities still require the manual intervention due to the complex characteristics of confined spaces, e.g., to remove the remains of the automatic cleaning process from the bottom of a tank. The results show that available technologies require more flexibility to adapt to such occupational environments and further research is needed.

Rapid Computation of Thermodynamic Properties over Multidimensional Nonbonded Parameter Spaces Using Adaptive Multistate Reweighting.

Science.gov (United States)

Naden, Levi N; Shirts, Michael R

2016-04-12

We show how thermodynamic properties of molecular models can be computed over a large, multidimensional parameter space by combining multistate reweighting analysis with a linear basis function approach. This approach reduces the computational cost to estimate thermodynamic properties from molecular simulations for over 130,000 tested parameter combinations from over 1000 CPU years to tens of CPU days. This speed increase is achieved primarily by computing the potential energy as a linear combination of basis functions, computed from either modified simulation code or as the difference of energy between two reference states, which can be done without any simulation code modification. The thermodynamic properties are then estimated with the Multistate Bennett Acceptance Ratio (MBAR) as a function of multiple model parameters without the need to define a priori how the states are connected by a pathway. Instead, we adaptively sample a set of points in parameter space to create mutual configuration space overlap. The existence of regions of poor configuration space overlap are detected by analyzing the eigenvalues of the sampled states' overlap matrix. The configuration space overlap to sampled states is monitored alongside the mean and maximum uncertainty to determine convergence, as neither the uncertainty or the configuration space overlap alone is a sufficient metric of convergence. This adaptive sampling scheme is demonstrated by estimating with high precision the solvation free energies of charged particles of Lennard-Jones plus Coulomb functional form with charges between -2 and +2 and generally physical values of σij and ϵij in TIP3P water. We also compute entropy, enthalpy, and radial distribution functions of arbitrary unsampled parameter combinations using only the data from these sampled states and use the estimates of free energies over the entire space to examine the deviation of atomistic simulations from the Born approximation to the solvation free

Tuning a space-time scalable PI controller using thermal parameters

Energy Technology Data Exchange (ETDEWEB)

Riverol, C. [University of West Indies, Chemical Engineering Department, St. Augustine, Trinidad (Trinidad and Tobago); Pilipovik, M.V. [Armach Engineers, Urb. Los Palos Grandes, Project Engineering Department, Caracas (Venezuela)

2005-03-01

The paper outlines the successful empirical design and validation of a space-time PI controller based on study of the controlled variable output as function of time and space. The developed control was implemented on two heat exchanger systems (falling film evaporator and milk pasteurizer). The strategy required adding a new term over the classical PI controller, such that a new parameter should be tuned. Measurements made on commercial installations have confirmed the validity of the new controller. (orig.)

Designing future dark energy space missions. II. Photometric redshift of space weak lensing optimized surveys

Science.gov (United States)

Jouvel, S.; Kneib, J.-P.; Bernstein, G.; Ilbert, O.; Jelinsky, P.; Milliard, B.; Ealet, A.; Schimd, C.; Dahlen, T.; Arnouts, S.

2011-08-01

scale of 0.15'', we found that a homogeneous survey reaching a survey population of IAB = 25.6 (10σ) with a sky coverage of ~11 000 deg2 maximizes the weak lensing FoM. The effective number density of galaxies used for WL is then ~45 gal/arcmin2, which is at least a factor of two higher than ground-based surveys. Conclusions: This study demonstrates that a full account of the observational strategy is required to properly optimize the instrument parameters and maximize the FoM of the future weak-lensing space dark energy mission.

Plasma physics and the 2013-2022 decadal survey in solar and space physics

Science.gov (United States)

Baker, Daniel N.

2016-11-01

The U.S. National Academies established in 2011 a steering committee to develop a comprehensive strategy for solar and space physics research. This updated and extended the first (2003) solar and space physics decadal survey. The latest decadal study implemented a 2008 Congressional directive to NASA for the fields of solar and space physics, but also addressed research in other federal agencies. The new survey broadly canvassed the fields of research to determine the current state of the discipline, identified the most important open scientific questions, and proposed the measurements and means to obtain them so as to advance the state of knowledge during the years 2013-2022. Research in this field has sought to understand: dynamical behaviour of the Sun and its heliosphere; properties of the space environments of the Earth and other solar system bodies; multiscale interaction between solar system plasmas and the interstellar medium; and energy transport throughout the solar system and its impact on the Earth and other solar system bodies. Research in solar and space plasma processes using observation, theory, laboratory studies, and numerical models has offered the prospect of understanding this interconnected system well enough to develop a predictive capability for operational support of civil and military space systems. We here describe the recommendations and strategic plans laid out in the 2013-2022 decadal survey as they relate to measurement capabilities and plasma physical research. We assess progress to date. We also identify further steps to achieve the Survey goals with an emphasis on plasma physical aspects of the program.

On equivalent parameter learning in simplified feature space based on Bayesian asymptotic analysis.

Science.gov (United States)

Yamazaki, Keisuke

2012-07-01

Parametric models for sequential data, such as hidden Markov models, stochastic context-free grammars, and linear dynamical systems, are widely used in time-series analysis and structural data analysis. Computation of the likelihood function is one of primary considerations in many learning methods. Iterative calculation of the likelihood such as the model selection is still time-consuming though there are effective algorithms based on dynamic programming. The present paper studies parameter learning in a simplified feature space to reduce the computational cost. Simplifying data is a common technique seen in feature selection and dimension reduction though an oversimplified space causes adverse learning results. Therefore, we mathematically investigate a condition of the feature map to have an asymptotically equivalent convergence point of estimated parameters, referred to as the vicarious map. As a demonstration to find vicarious maps, we consider the feature space, which limits the length of data, and derive a necessary length for parameter learning in hidden Markov models. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determination of charged particle beam parameters with taking into account of space charge

International Nuclear Information System (INIS)

Ishkhanov, B.S.; Poseryaev, A.V.; Shvedunov, V.I.

2005-01-01

One describes a procedure to determine the basic parameters of a paraxial axially-symmetric beam of charged particles taking account of space charge contribution. The described procedure is based on application of the general equation for beam envelope. Paper presents data on its convergence and resistance to measurement errors. The position determination error of crossover (stretching) and radius of beam in crossover is maximum 15% , while the emittance determination error depends on emittance and space charge correlation. The introduced procedure was used to determine parameters of the available electron gun 20 keV energy beam with 0.64 A current. The derived results turned to agree closely with the design parameters [ru

Measuring redshift-space distortions using photometric surveys

OpenAIRE

Ross, Ashley; Percival, Will; Crocce, M.; Cabre, A.; Gaztanaga, E.

2011-01-01

We outline how redshift-space distortions (RSD) can be measured from the angular correlation function w({\\theta}), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by comparing results from bins with top-hat galaxy selection in redshift, and bins based on the radial position of galaxy pair centres. This comparison can also be used to test the accuracy of the photometric redshifts. The presence of RSD will be clearly detectable ...

An Integrated Approach to Parameter Learning in Infinite-Dimensional Space

Energy Technology Data Exchange (ETDEWEB)

Boyd, Zachary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wendelberger, Joanne Roth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-14

The availability of sophisticated modern physics codes has greatly extended the ability of domain scientists to understand the processes underlying their observations of complicated processes, but it has also introduced the curse of dimensionality via the many user-set parameters available to tune. Many of these parameters are naturally expressed as functional data, such as initial temperature distributions, equations of state, and controls. Thus, when attempting to find parameters that match observed data, being able to navigate parameter-space becomes highly non-trivial, especially considering that accurate simulations can be expensive both in terms of time and money. Existing solutions include batch-parallel simulations, high-dimensional, derivative-free optimization, and expert guessing, all of which make some contribution to solving the problem but do not completely resolve the issue. In this work, we explore the possibility of coupling together all three of the techniques just described by designing user-guided, batch-parallel optimization schemes. Our motivating example is a neutron diffusion partial differential equation where the time-varying multiplication factor serves as the unknown control parameter to be learned. We find that a simple, batch-parallelizable, random-walk scheme is able to make some progress on the problem but does not by itself produce satisfactory results. After reducing the dimensionality of the problem using functional principal component analysis (fPCA), we are able to track the progress of the solver in a visually simple way as well as viewing the associated principle components. This allows a human to make reasonable guesses about which points in the state space the random walker should try next. Thus, by combining the random walker's ability to find descent directions with the human's understanding of the underlying physics, it is possible to use expensive simulations more efficiently and more quickly arrive at the

The magnetically driven imploding liner parameter space of the ATLAS capacitor bank

CERN Document Server

Lindemuth, I R; Faehl, R J; Reinovsky, R E

2001-01-01

Summary form only given, as follows. The Atlas capacitor bank (23 MJ, 30 MA) is now operational at Los Alamos. Atlas was designed primarily to magnetically drive imploding liners for use as impactors in shock and hydrodynamic experiments. We have conducted a computational "mapping" of the high-performance imploding liner parameter space accessible to Atlas. The effect of charge voltage, transmission inductance, liner thickness, liner initial radius, and liner length has been investigated. One conclusion is that Atlas is ideally suited to be a liner driver for liner-on-plasma experiments in a magnetized target fusion (MTF) context . The parameter space of possible Atlas reconfigurations has also been investigated.

Efficiently enclosing the compact binary parameter space by singular-value decomposition

International Nuclear Information System (INIS)

Cannon, Kipp; Hanna, Chad; Keppel, Drew

2011-01-01

Gravitational-wave searches for the merger of compact binaries use matched filtering as the method of detecting signals and estimating parameters. Such searches construct a fine mesh of filters covering a signal parameter space at high density. Previously it has been shown that singular-value decomposition can reduce the effective number of filters required to search the data. Here we study how the basis provided by the singular-value decomposition changes dimension as a function of template-bank density. We will demonstrate that it is sufficient to use the basis provided by the singular-value decomposition of a low-density bank to accurately reconstruct arbitrary points within the boundaries of the template bank. Since this technique is purely numerical, it may have applications to interpolating the space of numerical relativity waveforms.

What Are They Doing and What Do They Want: The Library Spaces Customer Survey at Edmonton Public Library

Directory of Open Access Journals (Sweden)

Beth Wortman

2012-12-01

Full Text Available As part of its Library Spaces Business Plan initiative, for four weeks in early 2012 Edmonton Public Library (EPL conducted a survey of its customers about how they use the library’s spaces and what they want from their library spaces. Using both print and online versions, the survey received 1517 responses which collected both quantitative and qualitative data. Findings revealed the ongoing importance of collections and quiet in library spaces, as well as the growing importance of providing social and group space in the library. Results of the survey indicate EPL’s customers do not consider the spaces a separate aspect from the collections and services the library provides. The results of the survey also emphasized the importance of regularly consulting with customers about library spaces to ensure the spaces continue to fulfill their needs as the role of the library, and the space needs associated with it, evolve.

Recovering a Probabilistic Knowledge Structure by Constraining Its Parameter Space

Science.gov (United States)

Stefanutti, Luca; Robusto, Egidio

2009-01-01

In the Basic Local Independence Model (BLIM) of Doignon and Falmagne ("Knowledge Spaces," Springer, Berlin, 1999), the probabilistic relationship between the latent knowledge states and the observable response patterns is established by the introduction of a pair of parameters for each of the problems: a lucky guess probability and a careless…

Exploring short-GRB afterglow parameter space for observations in coincidence with gravitational waves

Science.gov (United States)

Saleem, M.; Resmi, L.; Misra, Kuntal; Pai, Archana; Arun, K. G.

2018-03-01

Short duration Gamma Ray Bursts (SGRB) and their afterglows are among the most promising electromagnetic (EM) counterparts of Neutron Star (NS) mergers. The afterglow emission is broad-band, visible across the entire electromagnetic window from γ-ray to radio frequencies. The flux evolution in these frequencies is sensitive to the multidimensional afterglow physical parameter space. Observations of gravitational wave (GW) from BNS mergers in spatial and temporal coincidence with SGRB and associated afterglows can provide valuable constraints on afterglow physics. We run simulations of GW-detected BNS events and assuming that all of them are associated with a GRB jet which also produces an afterglow, investigate how detections or non-detections in X-ray, optical and radio frequencies can be influenced by the parameter space. We narrow down the regions of afterglow parameter space for a uniform top-hat jet model, which would result in different detection scenarios. We list inferences which can be drawn on the physics of GRB afterglows from multimessenger astronomy with coincident GW-EM observations.

Effects of space-dependent cross sections on core physics parameters for compact fast spectrum space power reactors

International Nuclear Information System (INIS)

Lell, R.M.; Hanan, N.A.

1987-01-01

Effects of multigroup neutron cross section generation procedures on core physics parameters for compact fast spectrum reactors have been examined. Homogeneous and space-dependent multigroup cross section sets were generated in 11 and 27 groups for a representative fast reactor core. These cross sections were used to compute various reactor physics parameters for the reference core. Coarse group structure and neglect of space-dependence in the generation procedure resulted in inaccurate computations of reactor flux and power distributions and in significant errors regarding estimates of core reactivity and control system worth. Delayed neutron fraction was insensitive to cross section treatment, and computed reactivity coefficients were only slightly sensitive. However, neutron lifetime was found to be very sensitive to cross section treatment. Deficiencies in multigroup cross sections are reflected in core nuclear design and, consequently, in system mechanical design

B→τν: Opening up the charged Higgs parameter space with R-parity violation

International Nuclear Information System (INIS)

Bose, Roshni; Kundu, Anirban

2012-01-01

The theoretically clean channel B + →τ + ν shows a close to 3σ discrepancy between the Standard Model prediction and the data. This in turn puts a strong constraint on the parameter space of a two-Higgs doublet model, including R-parity conserving supersymmetry. The constraint is so strong that it almost smells of fine-tuning. We show how the parameter space opens up with the introduction of suitable R-parity violating interactions, and release the tension between data and theory.

A survey on Frȯlicher spaces | Batubenge | Quaestiones ...

African Journals Online (AJOL)

This survey paper highlights a series of results in recent research on topology, geometry and categorical properties of spaces provided with a new structure in the ... More precisely, the present study will give the state of research on this topic which historically links a fundamental theorem of calculus in Rn so called Boman's ...

Entropy considerations in constraining the mSUGRA parameter space

International Nuclear Information System (INIS)

Nunez, Dario; Sussman, Roberto A.; Zavala, Jesus; Nellen, Lukas; Cabral-Rosetti, Luis G.; Mondragon, Myriam

2006-01-01

We explore the use of two criteria to constraint the allowed parameter space in mSUGRA models. Both criteria are based in the calculation of the present density of neutralinos as dark matter in the Universe. The first one is the usual ''abundance'' criterion which is used to calculate the relic density after the ''freeze-out'' era. To compute the relic density we used the numerical public code micrOMEGAs. The second criterion applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas evaluating then the change in the entropy per particle of this gas between the ''freeze-out'' era and present day virialized structures (i.e systems in virial equilibrium). An ''entropy-consistency'' criterion emerges by comparing theoretical and empirical estimates of this entropy. The main objective of our work is to determine for which regions of the parameter space in the mSUGRA model are both criteria consistent with the 2σ bounds according to WMAP for the relic density: 0.0945 < ΩCDMh2 < 0.1287. As a first result, we found that for A0 = 0, sgnμ +, small values of tanβ are not favored; only for tanβ ≅ 50 are both criteria significantly consistent

Constraining omega and bias from the Stromlo-APM survey

International Nuclear Information System (INIS)

Loveday, J.

1995-05-01

Galaxy redshift surveys provide a distorted picture of the universe due to the non-Hubble component of galaxy motions. By measuring such distortions in the linear regime one can constrain the quantity β = Ω 0.6 where Ω is the cosmological density parameter and b is the (linear) bias factor for optically-selected galaxies. In this paper we estimate β from the Stromlo-APM redshift survey by comparing the amplitude of the direction-averaged redshift space correlation function to the real space correlation function. We find a 95% confidence upper limit of β = 0.75, with a 'best estimate' of β ∼ 0.48. A bias parameter b ∼ 2 is thus required if Ω ≡ 1. However, higher-order correlations measured from the APM galaxy survey indicate a low value for the bias parameter b ∼ 1, requiring that Q approx-lt 0.6

Legal Parameters of Space Tourism

OpenAIRE

Smith, Lesley Jane; Hörl, Kay-Uwe

2004-01-01

The commercial concept of space tourism raises important legal issues not specifically addressed by first generation rules of international spacelaw. The principles established in the nineteen sixties and seventies were inspired by the philosophy that exploration of space was undertaken by and for the benefit of mankind. Technical developments since then haveincreased the potential for new space applications, with a corresponding increase in commercial interest in space. If space tourism is t...

Space closing versus space opening for bilateral missing upper laterals - aesthetic judgments of laypeople: a web-based survey.

Science.gov (United States)

Qadri, Salim; Parkin, Nicola A; Benson, Philip E

2016-06-01

To investigate the opinions of laypeople regarding the aesthetic outcome of treating patients with developmental absence of both maxillary lateral incisors using either orthodontic space closure (OSC) or space opening and prosthetic replacement (PR). Cross sectional, web-based survey. A panel of five orthodontists and five restorative dentists examined post-treatment intra-oral images of 21 patients with developmental absence of both upper lateral incisors. A consensus view was obtained about the 10 most attractive images (5 OSC; 5 PR). The 10 selected images were used in a web-based survey involving staff and students at the University of Sheffield. In the first section, the participants were asked to evaluate the attractiveness of the 10 randomly arranged single images using a 5-point Likert scale. In the second section, an image of OSC was paired with an image of PR according to their attractiveness ranking by the clinician panel, and the participants were asked to indicate which of the two images they preferred. The survey received 959 completed responses with 9590 judgements. The images of OSC were perceived to be more attractive (mean rating 3·34 out of 5; SD 0·56) compared with the images of PR (mean rating 3·14 out of 5; SD 0·58) (mean diff 0·21; P Space closing was perceived to be more attractive than space opening by lay people. The findings have implications for advising patients about the best aesthetic outcome when both maxillary lateral incisors are missing.

Relevance of the futron/zogby survey conclusions to the current space tourism industry

Science.gov (United States)

Ziliotto, Véronique

2010-06-01

Thanks to recent technological achievements such as Burt Rutan's SpaceShipOne in 2004, Bigelow's Genesis I in July 2006 and Genesis II in July 2007 and the success of space adventures' flights to the ISS, space tourism is leaving the realm of science-fiction. It is now becoming increasingly familiar to the general public and even recognized by institutional bodies. The Futron/Zogby survey, revised in 2006 and completed with the 2006. Adventurers survey constitutes a good basis to understanding the characteristics of the nascent suborbital market and the profile of the potential customers for both suborbital and orbital travel. The previsions of these studies will be contrasted with recent market and customers' data that was not available at the time.

Global Survey on Future Trends in Human Spaceflight: the Implications for Space Tourism

Science.gov (United States)

Gurtuna, O.; Garneau, S.

2002-01-01

With the much-publicized first ever space tourist flight, of Dennis Tito, and the announcement of the second space tourist flight to take place in April 2002, it is clear that an alternative motivation for human spaceflight has emerged. Human spaceflight is no longer only about meeting the priorities of national governments and space agencies, but is also about the tangible possibility of ordinary people seeing the Earth from a previously exclusive vantage point. It is imperative that major space players look beyond the existing human spaceflight rationale to identify some of the major driving forces behind space tourism, including the evolving market potential and developments in enabling technologies. In order to determine the influence of these forces on the future of commercial human spaceflight, the responses of a Futuraspace survey on future trends in human spaceflight are analyzed and presented. The motivation of this study is to identify sought-after space destinations, explore the expected trends in enabling technologies, and understand the future role of emerging space players. The survey will reflect the opinions of respondents from around the world including North America, Europe (including Russia) and Asia. The profiles of targeted respondents from space industry, government and academia are high-level executives/managers, senior researchers, as well as former and current astronauts. The survey instrument is a questionnaire which is validated by a pilot study. The sampling method is non-probabilistic, targeting as many space experts as possible who fit our intended respondent profile. Descriptive and comparative statistical analysis methods are implemented to investigate both global and regional perceptions of future commercial trends in human spaceflight. This study is not intended to be a formal market study of the potential viability of the space tourism market. Instead, the focus is on the future trends of human spaceflight, by drawing on the

Application and optimization of input parameter spaces in mass flow modelling: a case study with r.randomwalk and r.ranger

Science.gov (United States)

Krenn, Julia; Zangerl, Christian; Mergili, Martin

2017-04-01

r.randomwalk is a GIS-based, multi-functional, conceptual open source model application for forward and backward analyses of the propagation of mass flows. It relies on a set of empirically derived, uncertain input parameters. In contrast to many other tools, r.randomwalk accepts input parameter ranges (or, in case of two or more parameters, spaces) in order to directly account for these uncertainties. Parameter spaces represent a possibility to withdraw from discrete input values which in most cases are likely to be off target. r.randomwalk automatically performs multiple calculations with various parameter combinations in a given parameter space, resulting in the impact indicator index (III) which denotes the fraction of parameter value combinations predicting an impact on a given pixel. Still, there is a need to constrain the parameter space used for a certain process type or magnitude prior to performing forward calculations. This can be done by optimizing the parameter space in terms of bringing the model results in line with well-documented past events. As most existing parameter optimization algorithms are designed for discrete values rather than for ranges or spaces, the necessity for a new and innovative technique arises. The present study aims at developing such a technique and at applying it to derive guiding parameter spaces for the forward calculation of rock avalanches through back-calculation of multiple events. In order to automatize the work flow we have designed r.ranger, an optimization and sensitivity analysis tool for parameter spaces which can be directly coupled to r.randomwalk. With r.ranger we apply a nested approach where the total value range of each parameter is divided into various levels of subranges. All possible combinations of subranges of all parameters are tested for the performance of the associated pattern of III. Performance indicators are the area under the ROC curve (AUROC) and the factor of conservativeness (FoC). This

THE GHOSTS SURVEY. I. HUBBLE SPACE TELESCOPE ADVANCED CAMERA FOR SURVEYS DATA

International Nuclear Information System (INIS)

Radburn-Smith, D. J.; Dalcanton, J. J.; De Jong, R. S.; Streich, D.; Vlajic, M.; Seth, A. C.; Bailin, J.; Bell, E. F.; Brown, T. M.; Ferguson, H. C.; Goudfrooij, P.; Holfeltz, S.; Bullock, J. S.; Courteau, S.; Sick, J.; Holwerda, B. W.; Purcell, C.; Zucker, D. B.

2011-01-01

We present an overview of the GHOSTS survey, the largest study to date of the resolved stellar populations in the outskirts of disk galaxies. The sample consists of 14 disk galaxies within 17 Mpc, whose outer disks and halos are imaged with the Hubble Space Telescope Advanced Camera for Surveys (ACS). In the first paper of this series, we describe the sample, explore the benefits of using resolved stellar populations, and discuss our ACS F606W and F814W photometry. We use artificial star tests to assess completeness and use overlapping regions to estimate photometric uncertainties. The median depth of the survey at 50% completeness is 2.7 mag below the tip of the red giant branch (TRGB). We comprehensively explore and parameterize contamination from unresolved background galaxies and foreground stars using archival fields of high-redshift ACS observations. Left uncorrected, these would account for 10 0.65xF814W-19.0 detections per mag per arcsec 2 . We therefore identify several selection criteria that typically remove 95% of the contaminants. Even with these culls, background galaxies are a significant limitation to the surface brightness detection limit which, for this survey, is typically V ∼ 30 mag arcsec -2 . The resulting photometric catalogs are publicly available and contain some 3.1 million stars across 76 ACS fields, predominantly of low extinction. The uniform magnitudes of TRGB stars in these fields enable galaxy distance estimates with 2%-7% accuracy.

The Legion Support for Advanced Parameter-Space Studies on a Grid

National Research Council Canada - National Science Library

Natrajan, Anand; Humphrey, Marty A; Grimshaw, Andrew S

2006-01-01

.... Legion provides tools and services that support advanced parameter-space studies, i.e., studies that make complex demands such as transparent access to distributed files, fault-tolerance and security. We demonstrate these benefits with a protein-folding experiment in which a molecular simulation package was run over a grid managed by Legion.

A Hubble Space Telescope Survey of the Disk Cluster Population of M31. II. Advanced Camera for Surveys Pointings

Science.gov (United States)

Krienke, O. K.; Hodge, P. W.

2008-01-01

This paper reports on a survey of star clusters in M31 based on archival images from the Hubble Space Telescope. Paper I reported results from images obtained with the Wide Field Planetary Camera 2 (WFPC2) and this paper reports results from the Advanced Camera for Surveys (ACS). The ACS survey has yielded a total of 339 star clusters, 52 of which—mostly globular clusters—were found to have been cataloged previously. As for the previous survey, the luminosity function of the clusters drops steeply for absolute magnitudes fainter than MV = -3 the implied cluster mass function has a turnover for masses less than a few hundred solar masses. The color-integrated magnitude diagram of clusters shows three significant features: (1) a group of very red, luminous objects: the globular clusters, (2) a wide range in color for the fainter clusters, representing a considerable range in age and reddening, and (3) a maximum density of clusters centered approximately at V = 21, B - V = 0.30, V - I = 0.50, where there are intermediate-age, intermediate-mass clusters with ages close to 500 million years and masses of about 2000 solar masses. We give a brief qualitative interpretation of the distribution of clusters in the CMDs in terms of their formation and destruction rates. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for research in astronomy, Inc., under NASA contract NAS 5-26555.

Scattering-parameter extraction and calibration techniques for RF free-space material characterization

DEFF Research Database (Denmark)

Kaniecki, M.; Saenz, E.; Rolo, L.

2014-01-01

This paper demonstrates a method for material characterization (permittivity, permeability, loss tangent) based on the scattering parameters. The performance of the extraction algorithm will be shown for modelled and measured data. The measurements were carried out at the European Space Agency...

Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey

Science.gov (United States)

Ghezzi, Luan; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Cargile, Phillip; Ge, Jian; Pepper, Joshua; Wang, Ji; Paegert, Martin

2014-12-01

Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff, metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ~ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff, 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test was

Review of the different methods to derive average spacing from resolved resonance parameters sets

International Nuclear Information System (INIS)

Fort, E.; Derrien, H.; Lafond, D.

1979-12-01

The average spacing of resonances is an important parameter for statistical model calculations, especially concerning non fissile nuclei. The different methods to derive this average value from resonance parameters sets have been reviewed and analyzed in order to tentatively detect their respective weaknesses and propose recommendations. Possible improvements are suggested

Parameters of electromagnetic weather in near-terrestrial space determining the effects on biosystems

International Nuclear Information System (INIS)

Oraevskij, V.N.; Golyshev, S.A.; Levitin, A.E.; Breus, T.K.; Ivanova, S.V.; Komarov, F.I.; Rapoport, S.I.

1995-01-01

Space and time distribution of the electric and magnetic fields and current systems in the near terrestrial space (electromagnetic weather) were studied in connection with ambulance calls in Moscow, Russia, related to the cardia-vascular diseases. The some examples of the correlations between the solar activity parameters and geomagnetic variations and the events of the extreme number of ambulance calls were presented. 4 refs., 5 figs., 2 tabs

Survey of orbital dynamics and control of space rendezvous

Directory of Open Access Journals (Sweden)

Luo Yazhong

2014-02-01

Full Text Available Rendezvous orbital dynamics and control (RODC is a key technology for operating space rendezvous and docking missions. This paper surveys the studies on RODC. Firstly, the basic relative dynamics equation set is introduced and its improved versions are evaluated. Secondly, studies on rendezvous trajectory optimization are commented from three aspects: the linear rendezvous, the nonlinear two-body rendezvous, and the perturbed and constrained rendezvous. Thirdly, studies on relative navigation are briefly reviewed, and then close-range control methods including automated control, manual control, and telecontrol are analyzed. Fourthly, advances in rendezvous trajectory safety and robust analysis are surveyed, and their applications in trajectory optimization are discussed. Finally, conclusions are drawn and prospects of studies on RODC are presented.

Experimental identification of a comb-shaped chaotic region in multiple parameter spaces simulated by the Hindmarsh—Rose neuron model

Science.gov (United States)

Jia, Bing

2014-03-01

A comb-shaped chaotic region has been simulated in multiple two-dimensional parameter spaces using the Hindmarsh—Rose (HR) neuron model in many recent studies, which can interpret almost all of the previously simulated bifurcation processes with chaos in neural firing patterns. In the present paper, a comb-shaped chaotic region in a two-dimensional parameter space was reproduced, which presented different processes of period-adding bifurcations with chaos with changing one parameter and fixed the other parameter at different levels. In the biological experiments, different period-adding bifurcation scenarios with chaos by decreasing the extra-cellular calcium concentration were observed from some neural pacemakers at different levels of extra-cellular 4-aminopyridine concentration and from other pacemakers at different levels of extra-cellular caesium concentration. By using the nonlinear time series analysis method, the deterministic dynamics of the experimental chaotic firings were investigated. The period-adding bifurcations with chaos observed in the experiments resembled those simulated in the comb-shaped chaotic region using the HR model. The experimental results show that period-adding bifurcations with chaos are preserved in different two-dimensional parameter spaces, which provides evidence of the existence of the comb-shaped chaotic region and a demonstration of the simulation results in different two-dimensional parameter spaces in the HR neuron model. The results also present relationships between different firing patterns in two-dimensional parameter spaces.

Experimental identification of a comb-shaped chaotic region in multiple parameter spaces simulated by the Hindmarsh—Rose neuron model

International Nuclear Information System (INIS)

Jia Bing

2014-01-01

A comb-shaped chaotic region has been simulated in multiple two-dimensional parameter spaces using the Hindmarsh—Rose (HR) neuron model in many recent studies, which can interpret almost all of the previously simulated bifurcation processes with chaos in neural firing patterns. In the present paper, a comb-shaped chaotic region in a two-dimensional parameter space was reproduced, which presented different processes of period-adding bifurcations with chaos with changing one parameter and fixed the other parameter at different levels. In the biological experiments, different period-adding bifurcation scenarios with chaos by decreasing the extra-cellular calcium concentration were observed from some neural pacemakers at different levels of extra-cellular 4-aminopyridine concentration and from other pacemakers at different levels of extra-cellular caesium concentration. By using the nonlinear time series analysis method, the deterministic dynamics of the experimental chaotic firings were investigated. The period-adding bifurcations with chaos observed in the experiments resembled those simulated in the comb-shaped chaotic region using the HR model. The experimental results show that period-adding bifurcations with chaos are preserved in different two-dimensional parameter spaces, which provides evidence of the existence of the comb-shaped chaotic region and a demonstration of the simulation results in different two-dimensional parameter spaces in the HR neuron model. The results also present relationships between different firing patterns in two-dimensional parameter spaces

Modal survey testing of the Lidar In-space Technology Experiment (LITE) - A Space Shuttle payload

Science.gov (United States)

Anderson, J. B.; Coleman, A. D.; Driskill, T. C.; Lindell, M. C.

This paper presents the results of the modal survey test of the Lidar In-space Technology Experiment (LITE), a Space Shuttle payload mounted in a Spacelab flight single pallet. The test was performed by the Dynamics Test Branch at Marshall Space Flight Center, AL and run in two phases. In the first phase, an unloaded orthogrid connected to the pallet with 52 tension struts was tested. This test included 73 measurement points in three directions. In the second phase, the pallet was integrated with mass simulators mounted on the flight support structure to represent the dynamics (weight and center of gravity) of the various components comprising the LITE experiment and instrumented at 213 points in 3 directions. The test article was suspended by an air bag system to simulate a free-free boundary condition. This paper presents the results obtained from the testing and analytical model correlation efforts. The effect of the suspension system on the test article is also discussed.

The dynamics of blood biochemical parameters in cosmonauts during long-term space flights

Science.gov (United States)

Markin, Andrei; Strogonova, Lubov; Balashov, Oleg; Polyakov, Valery; Tigner, Timoty

Most of the previously obtained data on cosmonauts' metabolic state concerned certain stages of the postflight period. In this connection, all conclusions, as to metabolism peculiarities during the space flight, were to a large extent probabilistic. The purpose of this work was study of metabolism characteristics in cosmonauts directly during long-term space flights. In the capillary blood samples taken from a finger, by "Reflotron IV" biochemical analyzer, "Boehringer Mannheim" GmbH, Germany, adapted to weightlessness environments, the activity of GOT, GPT, CK, gamma-GT, total and pancreatic amylase, as well as concentration of hemoglobin, glucose, total bilirubin, uric acid, urea, creatinine, total, HDL- and LDL cholesterol, triglycerides had been determined. HDL/LDL-cholesterol ratio also was computed. The crewmembers of 6 main missions to the "Mir" orbital station, a total of 17 cosmonauts, were examined. Biochemical tests were carryed out 30-60 days before lounch, and in the flights different stages between the 25-th and the 423-rd days of flights. In cosmonauts during space flight had been found tendency to increase, in compare with basal level, GOT, GPT, total amylase activity, glucose and total cholesterol concentration, and tendency to decrease of CK activity, hemoglobin, HDL-cholesterol concentration, and HDL/LDL — cholesterol ratio. Some definite trends in variations of other determined biochemical parameters had not been found. The same trends of mentioned biochemical parameters alterations observed in majority of tested cosmonauts, allows to suppose existence of connection between noted metabolic alterations with influence of space flight conditions upon cosmonaut's body. Variations of other studied blood biochemical parameters depends on, probably, pure individual causes.

Shape, size, and robustness: feasible regions in the parameter space of biochemical networks.

Directory of Open Access Journals (Sweden)

Adel Dayarian

2009-01-01

Full Text Available The concept of robustness of regulatory networks has received much attention in the last decade. One measure of robustness has been associated with the volume of the feasible region, namely, the region in the parameter space in which the system is functional. In this paper, we show that, in addition to volume, the geometry of this region has important consequences for the robustness and the fragility of a network. We develop an approximation within which we could algebraically specify the feasible region. We analyze the segment polarity gene network to illustrate our approach. The study of random walks in the parameter space and how they exit the feasible region provide us with a rich perspective on the different modes of failure of this network model. In particular, we found that, between two alternative ways of activating Wingless, one is more robust than the other. Our method provides a more complete measure of robustness to parameter variation. As a general modeling strategy, our approach is an interesting alternative to Boolean representation of biochemical networks.

Accurate atmospheric parameters at moderate resolution using spectral indices: Preliminary application to the marvels survey

International Nuclear Information System (INIS)

Ghezzi, Luan; Da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; Ge, Jian; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Cargile, Phillip; Pepper, Joshua; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Wang, Ji

2014-01-01

Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff , metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ∼ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff , 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test

Influence of Population Variation of Physiological Parameters in Computational Models of Space Physiology

Science.gov (United States)

Myers, J. G.; Feola, A.; Werner, C.; Nelson, E. S.; Raykin, J.; Samuels, B.; Ethier, C. R.

2016-01-01

The earliest manifestations of Visual Impairment and Intracranial Pressure (VIIP) syndrome become evident after months of spaceflight and include a variety of ophthalmic changes, including posterior globe flattening and distension of the optic nerve sheath. Prevailing evidence links the occurrence of VIIP to the cephalic fluid shift induced by microgravity and the subsequent pressure changes around the optic nerve and eye. Deducing the etiology of VIIP is challenging due to the wide range of physiological parameters that may be influenced by spaceflight and are required to address a realistic spectrum of physiological responses. Here, we report on the application of an efficient approach to interrogating physiological parameter space through computational modeling. Specifically, we assess the influence of uncertainty in input parameters for two models of VIIP syndrome: a lumped-parameter model (LPM) of the cardiovascular and central nervous systems, and a finite-element model (FEM) of the posterior eye, optic nerve head (ONH) and optic nerve sheath. Methods: To investigate the parameter space in each model, we employed Latin hypercube sampling partial rank correlation coefficient (LHSPRCC) strategies. LHS techniques outperform Monte Carlo approaches by enforcing efficient sampling across the entire range of all parameters. The PRCC method estimates the sensitivity of model outputs to these parameters while adjusting for the linear effects of all other inputs. The LPM analysis addressed uncertainties in 42 physiological parameters, such as initial compartmental volume and nominal compartment percentage of total cardiac output in the supine state, while the FEM evaluated the effects on biomechanical strain from uncertainties in 23 material and pressure parameters for the ocular anatomy. Results and Conclusion: The LPM analysis identified several key factors including high sensitivity to the initial fluid distribution. The FEM study found that intraocular pressure and

S-COSMOS: The Spitzer Legacy Survey of the Hubble Space Telescope ACS 2 deg2 COSMOS Field I: Survey Strategy and First Analysis

Science.gov (United States)

Sanders, D. B.; Salvato, M.; Aussel, H.; Ilbert, O.; Scoville, N.; Surace, J. A.; Frayer, D. T.; Sheth, K.; Helou, G.; Brooke, T.; Bhattacharya, B.; Yan, L.; Kartaltepe, J. S.; Barnes, J. E.; Blain, A. W.; Calzetti, D.; Capak, P.; Carilli, C.; Carollo, C. M.; Comastri, A.; Daddi, E.; Ellis, R. S.; Elvis, M.; Fall, S. M.; Franceschini, A.; Giavalisco, M.; Hasinger, G.; Impey, C.; Koekemoer, A.; Le Fèvre, O.; Lilly, S.; Liu, M. C.; McCracken, H. J.; Mobasher, B.; Renzini, A.; Rich, M.; Schinnerer, E.; Shopbell, P. L.; Taniguchi, Y.; Thompson, D. J.; Urry, C. M.; Williams, J. P.

2007-09-01

The COSMOS Spitzer survey (S-COSMOS) is a Legacy program (Cycles 2+3) designed to carry out a uniform deep survey of the full 2 deg2 COSMOS field in all seven Spitzer bands (3.6, 4.5, 5.6, 8.0, 24.0, 70.0, and 160.0 μm). This paper describes the survey parameters, mapping strategy, data reduction procedures, achieved sensitivities to date, and the complete data set for future reference. We show that the observed infrared backgrounds in the S-COSMOS field are within 10% of the predicted background levels. The fluctuations in the background at 24 μm have been measured and do not show any significant contribution from cirrus, as expected. In addition, we report on the number of asteroid detections in the low Galactic latitude COSMOS field. We use the Cycle 2 S-COSMOS data to determine preliminary number counts, and compare our results with those from previous Spitzer Legacy surveys (e.g., SWIRE, GOODS). The results from this ``first analysis'' confirm that the S-COSMOS survey will have sufficient sensitivity with IRAC to detect ~L* disks and spheroids out to z>~3, and with MIPS to detect ultraluminous starbursts and AGNs out to z~3 at 24 μm and out to z~1.5-2 at 70 and 160 μm. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555 also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by AURA under cooperative agreement with the National Science Foundation; the National Radio Astronomy

Nonlinear Prediction As A Tool For Determining Parameters For Phase Space Reconstruction In Meteorology

Science.gov (United States)

Miksovsky, J.; Raidl, A.

Time delays phase space reconstruction represents one of useful tools of nonlinear time series analysis, enabling number of applications. Its utilization requires the value of time delay to be known, as well as the value of embedding dimension. There are sev- eral methods how to estimate both these parameters. Typically, time delay is computed first, followed by embedding dimension. Our presented approach is slightly different - we reconstructed phase space for various combinations of mentioned parameters and used it for prediction by means of the nearest neighbours in the phase space. Then some measure of prediction's success was computed (correlation or RMSE, e.g.). The position of its global maximum (minimum) should indicate the suitable combination of time delay and embedding dimension. Several meteorological (particularly clima- tological) time series were used for the computations. We have also created a MS- Windows based program in order to implement this approach - its basic features will be presented as well.

Dynamical quantum Hall effect in the parameter space.

Science.gov (United States)

Gritsev, V; Polkovnikov, A

2012-04-24

Geometric phases in quantum mechanics play an extraordinary role in broadening our understanding of fundamental significance of geometry in nature. One of the best known examples is the Berry phase [M.V. Berry (1984), Proc. Royal. Soc. London A, 392:45], which naturally emerges in quantum adiabatic evolution. So far the applicability and measurements of the Berry phase were mostly limited to systems of weakly interacting quasi-particles, where interference experiments are feasible. Here we show how one can go beyond this limitation and observe the Berry curvature, and hence the Berry phase, in generic systems as a nonadiabatic response of physical observables to the rate of change of an external parameter. These results can be interpreted as a dynamical quantum Hall effect in a parameter space. The conventional quantum Hall effect is a particular example of the general relation if one views the electric field as a rate of change of the vector potential. We illustrate our findings by analyzing the response of interacting spin chains to a rotating magnetic field. We observe the quantization of this response, which we term the rotational quantum Hall effect.

KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering

Science.gov (United States)

Joudaki, Shahab; Blake, Chris; Johnson, Andrew; Amon, Alexandra; Asgari, Marika; Choi, Ami; Erben, Thomas; Glazebrook, Karl; Harnois-Déraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Hoekstra, Henk; Klaes, Dominik; Kuijken, Konrad; Lidman, Chris; Mead, Alexander; Miller, Lance; Parkinson, David; Poole, Gregory B.; Schneider, Peter; Viola, Massimo; Wolf, Christian

2018-03-01

We perform a combined analysis of cosmic shear tomography, galaxy-galaxy lensing tomography, and redshift-space multipole power spectra (monopole and quadrupole) using 450 deg2 of imaging data by the Kilo Degree Survey (KiDS-450) overlapping with two spectroscopic surveys: the 2-degree Field Lensing Survey (2dFLenS) and the Baryon Oscillation Spectroscopic Survey (BOSS). We restrict the galaxy-galaxy lensing and multipole power spectrum measurements to the overlapping regions with KiDS, and self-consistently compute the full covariance between the different observables using a large suite of N-body simulations. We methodically analyse different combinations of the observables, finding that the galaxy-galaxy lensing measurements are particularly useful in improving the constraint on the intrinsic alignment amplitude, while the multipole power spectra are useful in tightening the constraints along the lensing degeneracy direction. The fully combined constraint on S_8 ≡ σ _8 √{Ω _m/0.3}=0.742± 0.035, which is an improvement by 20 per cent compared to KiDS alone, corresponds to a 2.6σ discordance with Planck, and is not significantly affected by fitting to a more conservative set of scales. Given the tightening of the parameter space, we are unable to resolve the discordance with an extended cosmology that is simultaneously favoured in a model selection sense, including the sum of neutrino masses, curvature, evolving dark energy and modified gravity. The complementarity of our observables allows for constraints on modified gravity degrees of freedom that are not simultaneously bounded with either probe alone, and up to a factor of three improvement in the S8 constraint in the extended cosmology compared to KiDS alone.

Optimizing Methods of Obtaining Stellar Parameters for the H3 Survey

Science.gov (United States)

Ivory, KeShawn; Conroy, Charlie; Cargile, Phillip

2018-01-01

The Stellar Halo at High Resolution with Hectochelle Survey (H3) is in the process of observing and collecting stellar parameters for stars in the Milky Way's halo. With a goal of measuring radial velocities for fainter stars, it is crucial that we have optimal methods of obtaining this and other parameters from the data from these stars.The method currently developed is The Payne, named after Cecilia Payne-Gaposchkin, a code that uses neural networks and Markov Chain Monte Carlo methods to utilize both spectra and photometry to obtain values for stellar parameters. This project was to investigate the benefit of fitting both spectra and spectral energy distributions (SED). Mock spectra using the parameters of the Sun were created and noise was inserted at various signal to noise values. The Payne then fit each mock spectrum with and without a mock SED also generated from solar parameters. The result was that at high signal to noise, the spectrum dominated and the effect of fitting the SED was minimal. But at low signal to noise, the addition of the SED greatly decreased the standard deviation of the data and resulted in more accurate values for temperature and metallicity.

Quantum sensing of the phase-space-displacement parameters using a single trapped ion

Science.gov (United States)

Ivanov, Peter A.; Vitanov, Nikolay V.

2018-03-01

We introduce a quantum sensing protocol for detecting the parameters characterizing the phase-space displacement by using a single trapped ion as a quantum probe. We show that, thanks to the laser-induced coupling between the ion's internal states and the motion mode, the estimation of the two conjugated parameters describing the displacement can be efficiently performed by a set of measurements of the atomic state populations. Furthermore, we introduce a three-parameter protocol capable of detecting the magnitude, the transverse direction, and the phase of the displacement. We characterize the uncertainty of the two- and three-parameter problems in terms of the Fisher information and show that state projective measurement saturates the fundamental quantum Cramér-Rao bound.

Effects of two-temperature parameter and thermal nonlocal parameter on transient responses of a half-space subjected to ramp-type heating

Science.gov (United States)

Xue, Zhang-Na; Yu, Ya-Jun; Tian, Xiao-Geng

2017-07-01

Based upon the coupled thermoelasticity and Green and Lindsay theory, the new governing equations of two-temperature thermoelastic theory with thermal nonlocal parameter is formulated. To more realistically model thermal loading of a half-space surface, a linear temperature ramping function is adopted. Laplace transform techniques are used to get the general analytical solutions in Laplace domain, and the inverse Laplace transforms based on Fourier expansion techniques are numerically implemented to obtain the numerical solutions in time domain. Specific attention is paid to study the effect of thermal nonlocal parameter, ramping time, and two-temperature parameter on the distributions of temperature, displacement and stress distribution.

On the identifiability of inertia parameters of planar Multi-Body Space Systems

Science.gov (United States)

Nabavi-Chashmi, Seyed Yaser; Malaek, Seyed Mohammad-Bagher

2018-04-01

This work describes a new formulation to study the identifiability characteristics of Serially Linked Multi-body Space Systems (SLMBSS). The process exploits the so called "Lagrange Formulation" to develop a linear form of Equations of Motion w.r.t the system Inertia Parameters (IPs). Having developed a specific form of regressor matrix, we aim to expedite the identification process. The new approach allows analytical as well as numerical identification and identifiability analysis for different SLMBSSs' configurations. Moreover, the explicit forms of SLMBSSs identifiable parameters are derived by analyzing the identifiability characteristics of the robot. We further show that any SLMBSS designed with Variable Configurations Joint allows all IPs to be identifiable through comparing two successive identification outcomes. This feature paves the way to design new class of SLMBSS for which accurate identification of all IPs is at hand. Different case studies reveal that proposed formulation provides fast and accurate results, as required by the space applications. Further studies might be necessary for cases where planar-body assumption becomes inaccurate.

Parameter estimation in space systems using recurrent neural networks

Science.gov (United States)

Parlos, Alexander G.; Atiya, Amir F.; Sunkel, John W.

1991-01-01

The identification of time-varying parameters encountered in space systems is addressed, using artificial neural systems. A hybrid feedforward/feedback neural network, namely a recurrent multilayer perception, is used as the model structure in the nonlinear system identification. The feedforward portion of the network architecture provides its well-known interpolation property, while through recurrency and cross-talk, the local information feedback enables representation of temporal variations in the system nonlinearities. The standard back-propagation-learning algorithm is modified and it is used for both the off-line and on-line supervised training of the proposed hybrid network. The performance of recurrent multilayer perceptron networks in identifying parameters of nonlinear dynamic systems is investigated by estimating the mass properties of a representative large spacecraft. The changes in the spacecraft inertia are predicted using a trained neural network, during two configurations corresponding to the early and late stages of the spacecraft on-orbit assembly sequence. The proposed on-line mass properties estimation capability offers encouraging results, though, further research is warranted for training and testing the predictive capabilities of these networks beyond nominal spacecraft operations.

Scoping the parameter space for demo and the engineering test

International Nuclear Information System (INIS)

Meier, W R.

1999-01-01

In our IFE development plan, we have set a goal of building an Engineering Test Facility (ETF) for a total cost of $2B and a Demo for $3B. In Mike Campbell s presentation at Madison, we included a viewgraph with an example Demo that had 80 to 250 MWe of net power and showed a plausible argument that it could cost less than $3B. In this memo, I examine the design space for the Demo and then briefly for the ETF. Instead of attempting to estimate the costs of the drivers, I pose the question in a way to define R ampersand D goals: As a function of key design and performance parameters, how much can the driver cost if the total facility cost is limited to the specified goal? The design parameters examined for the Demo included target gain, driver energy, driver efficiency, and net power output. For the ETF; the design parameters are target gain, driver energy, and target yield. The resulting graphs of allowable driver cost determine the goals that the driver R ampersand D programs must seek to meet

Stabilization and discontinuity-capturing parameters for space-time flow computations with finite element and isogeometric discretizations

Science.gov (United States)

Takizawa, Kenji; Tezduyar, Tayfun E.; Otoguro, Yuto

2018-04-01

Stabilized methods, which have been very common in flow computations for many years, typically involve stabilization parameters, and discontinuity-capturing (DC) parameters if the method is supplemented with a DC term. Various well-performing stabilization and DC parameters have been introduced for stabilized space-time (ST) computational methods in the context of the advection-diffusion equation and the Navier-Stokes equations of incompressible and compressible flows. These parameters were all originally intended for finite element discretization but quite often used also for isogeometric discretization. The stabilization and DC parameters we present here for ST computations are in the context of the advection-diffusion equation and the Navier-Stokes equations of incompressible flows, target isogeometric discretization, and are also applicable to finite element discretization. The parameters are based on a direction-dependent element length expression. The expression is outcome of an easy to understand derivation. The key components of the derivation are mapping the direction vector from the physical ST element to the parent ST element, accounting for the discretization spacing along each of the parametric coordinates, and mapping what we have in the parent element back to the physical element. The test computations we present for pure-advection cases show that the parameters proposed result in good solution profiles.

Fast Estimation Method of Space-Time Two-Dimensional Positioning Parameters Based on Hadamard Product

Directory of Open Access Journals (Sweden)

Haiwen Li

2018-01-01

Full Text Available The estimation speed of positioning parameters determines the effectiveness of the positioning system. The time of arrival (TOA and direction of arrival (DOA parameters can be estimated by the space-time two-dimensional multiple signal classification (2D-MUSIC algorithm for array antenna. However, this algorithm needs much time to complete the two-dimensional pseudo spectral peak search, which makes it difficult to apply in practice. Aiming at solving this problem, a fast estimation method of space-time two-dimensional positioning parameters based on Hadamard product is proposed in orthogonal frequency division multiplexing (OFDM system, and the Cramer-Rao bound (CRB is also presented. Firstly, according to the channel frequency domain response vector of each array, the channel frequency domain estimation vector is constructed using the Hadamard product form containing location information. Then, the autocorrelation matrix of the channel response vector for the extended array element in frequency domain and the noise subspace are calculated successively. Finally, by combining the closed-form solution and parameter pairing, the fast joint estimation for time delay and arrival direction is accomplished. The theoretical analysis and simulation results show that the proposed algorithm can significantly reduce the computational complexity and guarantee that the estimation accuracy is not only better than estimating signal parameters via rotational invariance techniques (ESPRIT algorithm and 2D matrix pencil (MP algorithm but also close to 2D-MUSIC algorithm. Moreover, the proposed algorithm also has certain adaptability to multipath environment and effectively improves the ability of fast acquisition of location parameters.

A SURVEY OF THE PARAMETER SPACE OF THE COMPRESSIBLE LIQUID DROP MODEL AS APPLIED TO THE NEUTRON STAR INNER CRUST

International Nuclear Information System (INIS)

Newton, W. G.; Gearheart, M.; Li Baoan

2013-01-01

We present a systematic survey of the range of predictions of the neutron star inner crust composition, crust-core transition densities and pressures, and density range of the nuclear 'pasta' phases at the bottom of the crust provided by the compressible liquid drop model in light of the current experimental and theoretical constraints on model parameters. Using a Skyrme-like model for nuclear matter, we construct baseline sequences of crust models by consistently varying the density dependence of the bulk symmetry energy at nuclear saturation density, L, under two conditions: (1) that the magnitude of the symmetry energy at saturation density J is held constant, and (2) J correlates with L under the constraint that the pure neutron matter (PNM) equation of state (EoS) satisfies the results of ab initio calculations at low densities. Such baseline crust models facilitate consistent exploration of the L dependence of crustal properties. The remaining surface energy and symmetric nuclear matter parameters are systematically varied around the baseline, and different functional forms of the PNM EoS at sub-saturation densities implemented, to estimate theoretical 'error bars' for the baseline predictions. Inner crust composition and transition densities are shown to be most sensitive to the surface energy at very low proton fractions and to the behavior of the sub-saturation PNM EoS. Recent calculations of the energies of neutron drops suggest that the low-proton-fraction surface energy might be higher than predicted in Skyrme-like models, which our study suggests may result in a greatly reduced volume of pasta in the crust than conventionally predicted.

Properties of Griffin-Hill-Wheeler spaces - 2. one-parameters and two-conjugate parameter families of generator states

International Nuclear Information System (INIS)

Passos, E.J.V. de; Toledo Piza, A.F.R. de.

The properties of the subspaces of the many-body Hilbert space which are associated with the use of the Generator Coordinate Method (GCM) in connection with one parameter, and with two-conjugate parameter families of generator states are examined in detail. It is shown that natural orthonormal base vectors in each case are immediately related to Peierls-Voccoz and Peierls-Thouless projections respectively. Through the formal consideration of a canonical transformation to collective, P and Q, and intrinsic degrees of freedom, the properties of the GCM subspaces with respect to the kinematical separation of these degrees of freedom are discussed in detail. An application is made, using the ideas developed in this paper, a) to translation; b) to illustrate the qualitative understanting of the content of existing GCM calculations of giant ressonances in light nuclei and c) to the definition of appropriate asymptotic states in current GCM descriptions of scattering [pt

Cross-cultural issues in space operations: A survey study among ground personnel of the European Space Agency

Science.gov (United States)

Sandal, Gro Mjeldheim; Manzey, Dietrich

2009-12-01

Today's space operations involve co-working of people with different ethnical, professional and organisational backgrounds. The aim of this study was to examine the implications of cultural diversity for efficient collaboration within the European Space Agency (ESA), and between ESA employees and representatives from other agencies. ESA employees from European countries ( N=576) answered to the CULT Ground Survey. The results showed that differences in relation to leadership and decision making were the most important issues thought to interfere with efficient co-working within ESA, and between ESA employees and colleagues from other agencies. Employees who collaborated with more than three nationalities within ESA indicated most challenges in co-working due to differences in compliance, behavioural norms and competitiveness. Challenges in co-working differed between agencies, and these differences were consistent with value differences in the national populations. The results may have applied value for training of European employees working in international space program teams.

THE ACS SURVEY OF GALACTIC GLOBULAR CLUSTERS. IX. HORIZONTAL BRANCH MORPHOLOGY AND THE SECOND PARAMETER PHENOMENON

International Nuclear Information System (INIS)

Dotter, Aaron; Sarajedini, Ata; Anderson, Jay; Bedin, Luigi R.; Paust, Nathaniel; Reid, I. Neill; Aparicio, Antonio; MarIn-Franch, A.; Rosenberg, Alfred; Chaboyer, Brian; Majewski, Steven; Milone, Antonino; Piotto, Giampaolo; Siegel, Michael

2010-01-01

The horizontal branch (HB) morphology of globular clusters (GCs) is most strongly influenced by metallicity. The second parameter phenomenon, first described in the 1960s, acknowledges that metallicity alone is not enough to describe the HB morphology of all GCs. In particular, astronomers noticed that the outer Galactic halo contains GCs with redder HBs at a given metallicity than are found inside the solar circle. Thus, at least a second parameter was required to characterize HB morphology. While the term 'second parameter' has since come to be used in a broader context, its identity with respect to the original problem has not been conclusively determined. Here we analyze the median color difference between the HB and the red giant branch, hereafter denoted as Δ(V - I), measured from Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) photometry of 60 GCs within ∼20 kpc of the Galactic center. Analysis of this homogeneous data set reveals that, after the influence of metallicity has been removed from the data, the correlation between Δ(V - I) and age is stronger than that of any other parameter considered. Expanding the sample to include HST ACS and Wide Field Planetary Camera 2 photometry of the six most distant Galactic GCs lends additional support to the correlation between Δ(V - I) and age. This result is robust with respect to the adopted metallicity scale and the method of age determination, but must bear the caveat that high-quality, detailed abundance information is not available for a significant fraction of the sample. Furthermore, when a subset of GCs with similar metallicities and ages is considered, a correlation between Δ(V - I) and central luminosity density is exposed. With respect to the existence of GCs with anomalously red HBs at a given metallicity, we conclude that age is the second parameter and central density is most likely the third. Important problems related to HB morphology in GCs, notably multi-modal distributions

Parameter retrieval of chiral metamaterials based on the state-space approach.

Science.gov (United States)

Zarifi, Davoud; Soleimani, Mohammad; Abdolali, Ali

2013-08-01

This paper deals with the introduction of an approach for the electromagnetic characterization of homogeneous chiral layers. The proposed method is based on the state-space approach and properties of a 4×4 state transition matrix. Based on this, first, the forward problem analysis through the state-space method is reviewed and properties of the state transition matrix of a chiral layer are presented and proved as two theorems. The formulation of a proposed electromagnetic characterization method is then presented. In this method, scattering data for a linearly polarized plane wave incident normally on a homogeneous chiral slab are combined with properties of a state transition matrix and provide a powerful characterization method. The main difference with respect to other well-established retrieval procedures based on the use of the scattering parameters relies on the direct computation of the transfer matrix of the slab as opposed to the conventional calculation of the propagation constant and impedance of the modes supported by the medium. The proposed approach allows avoiding nonlinearity of the problem but requires getting enough equations to fulfill the task which was provided by considering some properties of the state transition matrix. To demonstrate the applicability and validity of the method, the constitutive parameters of two well-known dispersive chiral metamaterial structures at microwave frequencies are retrieved. The results show that the proposed method is robust and reliable.

Space dependence of reactivity parameters on reactor dynamic perturbation measurements

International Nuclear Information System (INIS)

Maletti, R.; Ziegenbein, D.

1985-01-01

Practical application of reactor-dynamic perturbation measurements for on-power determination of differential reactivity weight of control rods and power coefficients of reactivity has shown a significant dependence of parameters on the position of outcore detectors. The space dependence of neutron flux signal in the core of a VVER-440-type reactor was measured by means of 60 self-powered neutron detectors. The greatest neutron flux alterations are located close to moved control rods and in height of the perturbation position. By means of computations, detector positions can be found in the core in which the one-point model is almost valid. (author)

Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids

Science.gov (United States)

Evans, Nancy Remage; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Tingle, Evan; Karovska, Margarita; Pillitteri, Ignazio

2016-05-01

We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera 3 (WFC3) of 70 Galactic Cepheids, typically within 1 kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, based on their positions in color-magnitude diagrams, and having separations ⩾ 5'' from the Cepheids. We use follow-up observations of 14 of these candidates with XMM-Newton, and of one of them with ROSAT, to separate X-ray-active young stars (probable physical companions) from field stars (chance alignments). Our preliminary estimate, based on the optical and X-ray observations, is that only 3% of the Cepheids in the sample have wide companions. Our survey easily detects resolved main-sequence companions as faint as spectral type K. Thus the fact that the two most probable companions (those of FF Aql and RV Sco) are earlier than type K is not simply a function of the detection limit. We find no physical companions having separations larger than 4000 au in the X-ray survey. Two Cepheids are exceptions in that they do have young companions at significantly larger separations (δ Cep and S Nor), but both belong to a cluster or a loose association, so our working model is that they are not gravitationally bound binary members, but rather cluster/association members. All of these properties provide constraints on both star formation and subsequent dynamical evolution. The low frequency of true physical companions at separations > 5'' is confirmed by examination of the subset of the nearest Cepheids and also the density of the fields. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Probability Distribution for Flowing Interval Spacing

International Nuclear Information System (INIS)

S. Kuzio

2004-01-01

Fracture spacing is a key hydrologic parameter in analyses of matrix diffusion. Although the individual fractures that transmit flow in the saturated zone (SZ) cannot be identified directly, it is possible to determine the fractured zones that transmit flow from flow meter survey observations. The fractured zones that transmit flow as identified through borehole flow meter surveys have been defined in this report as flowing intervals. The flowing interval spacing is measured between the midpoints of each flowing interval. The determination of flowing interval spacing is important because the flowing interval spacing parameter is a key hydrologic parameter in SZ transport modeling, which impacts the extent of matrix diffusion in the SZ volcanic matrix. The output of this report is input to the ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, the analysis of data and development of a data distribution reported herein is used to develop the uncertainty distribution for the flowing interval spacing parameter for the SZ transport abstraction model. Figure 1-1 shows the relationship of this report to other model reports that also pertain to flow and transport in the SZ. Figure 1-1 also shows the flow of key information among the SZ reports. It should be noted that Figure 1-1 does not contain a complete representation of the data and parameter inputs and outputs of all SZ reports, nor does it show inputs external to this suite of SZ reports. Use of the developed flowing interval spacing probability distribution is subject to the limitations of the assumptions discussed in Sections 5 and 6 of this analysis report. The number of fractures in a flowing interval is not known. Therefore, the flowing intervals are assumed to be composed of one flowing zone in the transport simulations. This analysis may overestimate the flowing interval spacing because the number of fractures that contribute to a flowing interval cannot be

A SURVEY OF THE PARAMETER SPACE OF THE COMPRESSIBLE LIQUID DROP MODEL AS APPLIED TO THE NEUTRON STAR INNER CRUST

Energy Technology Data Exchange (ETDEWEB)

Newton, W. G.; Gearheart, M.; Li Baoan, E-mail: william.newton@tamuc.edu [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce, TX 75429-3011 (United States)

2013-01-15

We present a systematic survey of the range of predictions of the neutron star inner crust composition, crust-core transition densities and pressures, and density range of the nuclear 'pasta' phases at the bottom of the crust provided by the compressible liquid drop model in light of the current experimental and theoretical constraints on model parameters. Using a Skyrme-like model for nuclear matter, we construct baseline sequences of crust models by consistently varying the density dependence of the bulk symmetry energy at nuclear saturation density, L, under two conditions: (1) that the magnitude of the symmetry energy at saturation density J is held constant, and (2) J correlates with L under the constraint that the pure neutron matter (PNM) equation of state (EoS) satisfies the results of ab initio calculations at low densities. Such baseline crust models facilitate consistent exploration of the L dependence of crustal properties. The remaining surface energy and symmetric nuclear matter parameters are systematically varied around the baseline, and different functional forms of the PNM EoS at sub-saturation densities implemented, to estimate theoretical 'error bars' for the baseline predictions. Inner crust composition and transition densities are shown to be most sensitive to the surface energy at very low proton fractions and to the behavior of the sub-saturation PNM EoS. Recent calculations of the energies of neutron drops suggest that the low-proton-fraction surface energy might be higher than predicted in Skyrme-like models, which our study suggests may result in a greatly reduced volume of pasta in the crust than conventionally predicted.

Effects of self-calibration of intrinsic alignment on cosmological parameter constraints from future cosmic shear surveys

International Nuclear Information System (INIS)

Yao, Ji; Ishak, Mustapha; Lin, Weikang; Troxel, Michael

2017-01-01

Intrinsic alignments (IA) of galaxies have been recognized as one of the most serious contaminants to weak lensing. These systematics need to be isolated and mitigated in order for ongoing and future lensing surveys to reach their full potential. The IA self-calibration (SC) method was shown in previous studies to be able to reduce the GI contamination by up to a factor of 10 for the 2-point and 3-point correlations. The SC method does not require the assumption of an IA model in its working and can extract the GI signal from the same photo-z survey offering the possibility to test and understand structure formation scenarios and their relationship to IA models. In this paper, we study the effects of the IA SC mitigation method on the precision and accuracy of cosmological parameter constraints from future cosmic shear surveys LSST, WFIRST and Euclid. We perform analytical and numerical calculations to estimate the loss of precision and the residual bias in the best fit cosmological parameters after the self-calibration is performed. We take into account uncertainties from photometric redshifts and the galaxy bias. We find that the confidence contours are slightly inflated from applying the SC method itself while a significant increase is due to the inclusion of the photo-z uncertainties. The bias of cosmological parameters is reduced from several-σ, when IA is not corrected for, to below 1-σ after SC is applied. These numbers are comparable to those resulting from applying the method of marginalizing over IA model parameters despite the fact that the two methods operate very differently. We conclude that implementing the SC for these future cosmic-shear surveys will not only allow one to efficiently mitigate the GI contaminant but also help to understand their modeling and link to structure formation.

Effects of self-calibration of intrinsic alignment on cosmological parameter constraints from future cosmic shear surveys

Energy Technology Data Exchange (ETDEWEB)

Yao, Ji; Ishak, Mustapha; Lin, Weikang [Department of Physics, The University of Texas at Dallas, Dallas, TX 75080 (United States); Troxel, Michael, E-mail: jxy131230@utdallas.edu, E-mail: mxi054000@utdallas.edu, E-mail: wxl123830@utdallas.edu, E-mail: michael.a.troxel@gmail.com [Department of Physics, Ohio State University, Columbus, OH 43210 (United States)

2017-10-01

Intrinsic alignments (IA) of galaxies have been recognized as one of the most serious contaminants to weak lensing. These systematics need to be isolated and mitigated in order for ongoing and future lensing surveys to reach their full potential. The IA self-calibration (SC) method was shown in previous studies to be able to reduce the GI contamination by up to a factor of 10 for the 2-point and 3-point correlations. The SC method does not require the assumption of an IA model in its working and can extract the GI signal from the same photo-z survey offering the possibility to test and understand structure formation scenarios and their relationship to IA models. In this paper, we study the effects of the IA SC mitigation method on the precision and accuracy of cosmological parameter constraints from future cosmic shear surveys LSST, WFIRST and Euclid. We perform analytical and numerical calculations to estimate the loss of precision and the residual bias in the best fit cosmological parameters after the self-calibration is performed. We take into account uncertainties from photometric redshifts and the galaxy bias. We find that the confidence contours are slightly inflated from applying the SC method itself while a significant increase is due to the inclusion of the photo-z uncertainties. The bias of cosmological parameters is reduced from several-σ, when IA is not corrected for, to below 1-σ after SC is applied. These numbers are comparable to those resulting from applying the method of marginalizing over IA model parameters despite the fact that the two methods operate very differently. We conclude that implementing the SC for these future cosmic-shear surveys will not only allow one to efficiently mitigate the GI contaminant but also help to understand their modeling and link to structure formation.

Improved sampling for airborne surveys to estimate wildlife population parameters in the African Savannah

NARCIS (Netherlands)

Khaemba, W.; Stein, A.

2002-01-01

Parameter estimates, obtained from airborne surveys of wildlife populations, often have large bias and large standard errors. Sampling error is one of the major causes of this imprecision and the occurrence of many animals in herds violates the common assumptions in traditional sampling designs like

Evasive Maneuvers in Space Debris Environment and Technological Parameters

Directory of Open Access Journals (Sweden)

Antônio D. C. Jesus

2012-01-01

Full Text Available We present a study of collisional dynamics between space debris and an operational vehicle in LEO. We adopted an approach based on the relative dynamics between the objects on a collisional course and with a short warning time and established a semianalytical solution for the final trajectories of these objects. Our results show that there are angular ranges in 3D, in addition to the initial conditions, that favor the collisions. These results allowed the investigation of a range of technological parameters for the spacecraft (e.g., fuel reserve that allow a safe evasive maneuver (e.g., time available for the maneuver. The numerical model was tested for different values of the impact velocity and relative distance between the approaching objects.

Constraining the mSUGRA (minimal supergravity) parameter space using the entropy of dark matter halos

Energy Technology Data Exchange (ETDEWEB)

Nunez, Dario; Zavala, Jesus; Nellen, Lukas; Sussman, Roberto A [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (ICN-UNAM), AP 70-543, Mexico 04510 DF (Mexico); Cabral-Rosetti, Luis G [Departamento de Posgrado, Centro Interdisciplinario de Investigacion y Docencia en Educacion Tecnica (CIIDET), Avenida Universidad 282 Pte., Col. Centro, Apartado Postal 752, C. P. 76000, Santiago de Queretaro, Qro. (Mexico); Mondragon, Myriam, E-mail: nunez@nucleares.unam.mx, E-mail: jzavala@nucleares.unam.mx, E-mail: jzavala@shao.ac.cn, E-mail: lukas@nucleares.unam.mx, E-mail: sussman@nucleares.unam.mx, E-mail: lgcabral@ciidet.edu.mx, E-mail: myriam@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (IF-UNAM), Apartado Postal 20-364, 01000 Mexico DF (Mexico); Collaboration: For the Instituto Avanzado de Cosmologia, IAC

2008-05-15

We derive an expression for the entropy of a dark matter halo described using a Navarro-Frenk-White model with a core. The comparison of this entropy with that of dark matter in the freeze-out era allows us to constrain the parameter space in mSUGRA models. Moreover, combining these constraints with the ones obtained from the usual abundance criterion and demanding that these criteria be consistent with the 2{sigma} bounds for the abundance of dark matter: 0.112{<=}{Omega}{sub DM}h{sup 2}{<=}0.122, we are able to clearly identify validity regions among the values of tan{beta}, which is one of the parameters of the mSUGRA model. We found that for the regions of the parameter space explored, small values of tan{beta} are not favored; only for tan {beta} Asymptotically-Equal-To 50 are the two criteria significantly consistent. In the region where the two criteria are consistent we also found a lower bound for the neutralino mass, m{sub {chi}}{>=}141 GeV.

Constraining the mSUGRA (minimal supergravity) parameter space using the entropy of dark matter halos

International Nuclear Information System (INIS)

Núñez, Darío; Zavala, Jesús; Nellen, Lukas; Sussman, Roberto A; Cabral-Rosetti, Luis G; Mondragón, Myriam

2008-01-01

We derive an expression for the entropy of a dark matter halo described using a Navarro–Frenk–White model with a core. The comparison of this entropy with that of dark matter in the freeze-out era allows us to constrain the parameter space in mSUGRA models. Moreover, combining these constraints with the ones obtained from the usual abundance criterion and demanding that these criteria be consistent with the 2σ bounds for the abundance of dark matter: 0.112≤Ω DM h 2 ≤0.122, we are able to clearly identify validity regions among the values of tanβ, which is one of the parameters of the mSUGRA model. We found that for the regions of the parameter space explored, small values of tanβ are not favored; only for tan β ≃ 50 are the two criteria significantly consistent. In the region where the two criteria are consistent we also found a lower bound for the neutralino mass, m χ ≥141 GeV

Scanning the parameter space of collapsing rotating thin shells

Science.gov (United States)

Rocha, Jorge V.; Santarelli, Raphael

2018-06-01

We present results of a comprehensive study of collapsing and bouncing thin shells with rotation, framing it in the context of the weak cosmic censorship conjecture. The analysis is based on a formalism developed specifically for higher odd dimensions that is able to describe the dynamics of collapsing rotating shells exactly. We analyse and classify a plethora of shell trajectories in asymptotically flat spacetimes. The parameters varied include the shell’s mass and angular momentum, its radial velocity at infinity, the (linear) equation-of-state parameter and the spacetime dimensionality. We find that plunges of rotating shells into black holes never produce naked singularities, as long as the matter shell obeys the weak energy condition, and so respects cosmic censorship. This applies to collapses of dust shells starting from rest or with a finite velocity at infinity. Not even shells with a negative isotropic pressure component (i.e. tension) lead to the formation of naked singularities, as long as the weak energy condition is satisfied. Endowing the shells with a positive isotropic pressure component allows for the existence of bouncing trajectories satisfying the dominant energy condition and fully contained outside rotating black holes. Otherwise any turning point occurs always inside the horizon. These results are based on strong numerical evidence from scans of numerous sections in the large parameter space available to these collapsing shells. The generalisation of the radial equation of motion to a polytropic equation-of-state for the matter shell is also included in an appendix.

Impact of relativistic effects on cosmological parameter estimation

Science.gov (United States)

Lorenz, Christiane S.; Alonso, David; Ferreira, Pedro G.

2018-01-01

Future surveys will access large volumes of space and hence very long wavelength fluctuations of the matter density and gravitational field. It has been argued that the set of secondary effects that affect the galaxy distribution, relativistic in nature, will bring new, complementary cosmological constraints. We study this claim in detail by focusing on a subset of wide-area future surveys: Stage-4 cosmic microwave background experiments and photometric redshift surveys. In particular, we look at the magnification lensing contribution to galaxy clustering and general-relativistic corrections to all observables. We quantify the amount of information encoded in these effects in terms of the tightening of the final cosmological constraints as well as the potential bias in inferred parameters associated with neglecting them. We do so for a wide range of cosmological parameters, covering neutrino masses, standard dark-energy parametrizations and scalar-tensor gravity theories. Our results show that, while the effect of lensing magnification to number counts does not contain a significant amount of information when galaxy clustering is combined with cosmic shear measurements, this contribution does play a significant role in biasing estimates on a host of parameter families if unaccounted for. Since the amplitude of the magnification term is controlled by the slope of the source number counts with apparent magnitude, s (z ), we also estimate the accuracy to which this quantity must be known to avoid systematic parameter biases, finding that future surveys will need to determine s (z ) to the ˜5 %- 10 % level. On the contrary, large-scale general-relativistic corrections are irrelevant both in terms of information content and parameter bias for most cosmological parameters but significant for the level of primordial non-Gaussianity.

A General 2D Meshless Interpolating Boundary Node Method Based on the Parameter Space

Directory of Open Access Journals (Sweden)

Hongyin Yang

2017-01-01

Full Text Available The presented study proposed an improved interpolating boundary node method (IIBNM for 2D potential problems. The improved interpolating moving least-square (IIMLS method was applied to construct the shape functions, of which the delta function properties and boundary conditions were directly implemented. In addition, any weight function used in the moving least-square (MLS method was also applicable in the IIMLS method. Boundary cells were required in the computation of the boundary integrals, and additional discretization error was not avoided if traditional cells were used to approximate the geometry. The present study applied the parametric cells created in the parameter space to preserve the exact geometry, and the geometry was maintained due to the number of cells. Only the number of nodes on the boundary was required as additional information for boundary node construction. Most importantly, the IIMLS method can be applied in the parameter space to construct shape functions without the requirement of additional computations for the curve length.

Constraining the mSUGRA parameter space through entropy and abundance criteria

International Nuclear Information System (INIS)

Cabral-Rosetti, Luis G.; Mondragon, Myriam; Nunez, Dario; Sussman, Roberto A.; Zavala, Jesus; Nellen, Lukas

2007-01-01

We explore the use of two criteria to constrain the allowed parameter space in mSUGRA models; both criteria are based in the calculation of the present density of neutralinos χ0 as Dark Matter in the Universe. The first one is the usual ''abundance'' criterion that requieres that present neutralino relic density complies with 0.0945 < ΩCDMh2 < 0.1287, which are the 2σ bounds according to WMAP. To calculate the relic density we use the public numerical code micrOMEGAS. The second criterion is the original idea presented in [3] that basically applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas, and then evaluate the change in entropy per particle of this gas between the freeze-out era and present day virialized structures. An 'entropy consistency' criterion emerges by comparing theoretical and empirical estimates of this entropy. One of the objetives of the work is to analyze the joint application of both criteria, already done in [3], to see if their results, using approximations for the calculations of the relic density, agree with the results coming from the exact numerical results of micrOMEGAS. The main objetive of the work is to use this method to constrain the parameter space in mSUGRA models that are inputs for the calculations of micrOMEGAS, and thus to get some bounds on the predictions for the SUSY spectra

The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

Energy Technology Data Exchange (ETDEWEB)

Costa, Diogo Ricardo da, E-mail: diogo_cost@hotmail.com [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Hansen, Matheus [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Instituto de Física, Univ. São Paulo, Rua do Matão, Cidade Universitária, 05314-970, São Paulo – SP (Brazil); Guarise, Gustavo [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Medrano-T, Rene O. [Departamento de Ciências Exatas e da Terra, UNIFESP – Universidade Federal de São Paulo, Rua São Nicolau, 210, Centro, 09913-030, Diadema, SP (Brazil); Department of Mathematics, Imperial College London, London SW7 2AZ (United Kingdom); Leonel, Edson D. [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy)

2016-04-22

We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems. - Highlights: • Extreme orbits and the organization of periodic regions in parameter space. • One-dimensional dissipative mappings. • The circle map and also a time perturbed logistic map were studied.

The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

International Nuclear Information System (INIS)

Costa, Diogo Ricardo da; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

2016-01-01

We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems. - Highlights: • Extreme orbits and the organization of periodic regions in parameter space. • One-dimensional dissipative mappings. • The circle map and also a time perturbed logistic map were studied.

Halogenation of Hydraulic Fracturing Additives in the Shale Well Parameter Space

Science.gov (United States)

Sumner, A. J.; Plata, D.

2017-12-01

Horizontal Drilling and Hydraulic fracturing (HDHF) involves the deep-well injection of a `fracking fluid' composed of diverse and numerous chemical additives designed to facilitate the release and collection of natural gas from shale plays. The potential impacts of HDHF operations on water resources and ecosystems are numerous, and analyses of flowback samples revealed organic compounds from both geogenic and anthropogenic sources. Furthermore, halogenated chemicals were also detected, and these compounds are rarely disclosed, suggesting the in situ halogenation of reactive additives. To test this transformation hypothesis, we designed and operated a novel high pressure and temperature reactor system to simulate the shale well parameter space and investigate the chemical reactivity of twelve commonly disclosed and functionally diverse HDHF additives. Early results revealed an unanticipated halogenation pathway of α-β unsaturated aldehyde, Cinnamaldehyde, in the presence of oxidant and concentrated brine. Ongoing experiments over a range of parameters informed a proposed mechanism, demonstrating the role of various shale-well specific parameters in enabling the demonstrated halogenation pathway. Ultimately, these results will inform a host of potentially unintended interactions of HDHF additives during the extreme conditions down-bore of a shale well during HDHF activities.

Effect of alloy deformation on the average spacing parameters of non-deforming particles

International Nuclear Information System (INIS)

Fisher, J.; Gurland, J.

1980-02-01

It is shown on the basis of stereological definitions and a few simple experiments that the commonly used average dispersion parameters, area fraction (A/sub A/)/sub β/, areal particle density N/sub Aβ/ and mean free path lambda/sub α/, remain invariant during plastic deformation in the case of non-deforming equiaxed particles. Directional effects on the spacing parameters N/sub Aβ/ and lambda/sub α/ arise during uniaxial deformation by rotation and preferred orientation of nonequiaxed particles. Particle arrangement in stringered or layered structures and the effect of deformation on nearest neighbor distances of particles and voids are briefly discussed in relation to strength and fracture theories

Exposure to Neighborhood Green Space and Mental Health: Evidence from the Survey of the Health of Wisconsin

Directory of Open Access Journals (Sweden)

Kirsten M. M. Beyer

2014-03-01

Full Text Available Green space is now widely viewed as a health-promoting characteristic of residential environments, and has been linked to mental health benefits such as recovery from mental fatigue and reduced stress, particularly through experimental work in environmental psychology. Few population level studies have examined the relationships between green space and mental health. Further, few studies have considered the role of green space in non-urban settings. This study contributes a population-level perspective from the United States to examine the relationship between environmental green space and mental health outcomes in a study area that includes a spectrum of urban to rural environments. Multivariate survey regression analyses examine the association between green space and mental health using the unique, population-based Survey of the Health of Wisconsin database. Analyses were adjusted for length of residence in the neighborhood to reduce the impact of neighborhood selection bias. Higher levels of neighborhood green space were associated with significantly lower levels of symptomology for depression, anxiety and stress, after controlling for a wide range of confounding factors. Results suggest that “greening” could be a potential population mental health improvement strategy in the United States.

The effect of environmental parameters to dust concentration in air-conditioned space

Science.gov (United States)

Ismail, A. M. M.; Manssor, N. A. S.; Nalisa, A.; Yahaya, N.

2017-08-01

Malaysia has a wet and hot climate, therefore most of the spaces are air conditioned. The environment might affect dust concentration inside a space and affect the indoor air quality (IAQ). The main objective of this study is to study the dust concentration collected inside enclosed air-conditioned space. The measurement was done physically at four selected offices and two classrooms using a number of equipment to measure the dust concentration and environmental parameters which are temperature and relative air humidity. It was found that the highest dust concentration produced in office (temperature of 24.7°C, relative humidity of 66.5%) is 0.075 mg/m3, as compared to classroom, the highest dust concentration produced is 0.060 mg/m3 office (temperature of 25.9°C, relative humidity of 64.0%). However, both measurements show that value still within the safety level set by DOSH Malaysia (2005-2010) and ASHRAE 62.2 2016. The office contained higher dust concentration compared to classroom because of frequent movement transpires daily due to the functional of the offices.

Fast estimation of space-robots inertia parameters: A modular mathematical formulation

Science.gov (United States)

Nabavi Chashmi, Seyed Yaser; Malaek, Seyed Mohammad-Bagher

2016-10-01

This work aims to propose a new technique that considerably helps enhance time and precision needed to identify ;Inertia Parameters (IPs); of a typical Autonomous Space-Robot (ASR). Operations might include, capturing an unknown Target Space-Object (TSO), ;active space-debris removal; or ;automated in-orbit assemblies;. In these operations generating precise successive commands are essential to the success of the mission. We show how a generalized, repeatable estimation-process could play an effective role to manage the operation. With the help of the well-known Force-Based approach, a new ;modular formulation; has been developed to simultaneously identify IPs of an ASR while it captures a TSO. The idea is to reorganize the equations with associated IPs with a ;Modular Set; of matrices instead of a single matrix representing the overall system dynamics. The devised Modular Matrix Set will then facilitate the estimation process. It provides a conjugate linear model in mass and inertia terms. The new formulation is, therefore, well-suited for ;simultaneous estimation processes; using recursive algorithms like RLS. Further enhancements would be needed for cases the effect of center of mass location becomes important. Extensive case studies reveal that estimation time is drastically reduced which in-turn paves the way to acquire better results.

Hadronic total cross-sections through soft gluon summation in impact parameter space

International Nuclear Information System (INIS)

Grau, A.

1999-01-01

IThe Bloch-Nordsieck model for the parton distribution of hadrons in impact parameter space, constructed using soft gluon summation, is investigated in detail. Its dependence upon the infrared structure of the strong coupling constant α s is discussed, both for finite as well as singular, but integrable, α s . The formalism is applied to the prediction of total proton-proton and proton-antiproton cross-sections, where screening, due to soft gluon emission from the initial valence quarks, becomes evident

Effect of solar wind plasma parameters on space weather

International Nuclear Information System (INIS)

Rathore, Balveer S.; Gupta, Dinesh C.; Kaushik, Subhash C.

2015-01-01

Today's challenge for space weather research is to quantitatively predict the dynamics of the magnetosphere from measured solar wind and interplanetary magnetic field (IMF) conditions. Correlative studies between geomagnetic storms (GMSs) and the various interplanetary (IP) field/plasma parameters have been performed to search for the causes of geomagnetic activity and develop models for predicting the occurrence of GMSs, which are important for space weather predictions. We find a possible relation between GMSs and solar wind and IMF parameters in three different situations and also derived the linear relation for all parameters in three situations. On the basis of the present statistical study, we develop an empirical model. With the help of this model, we can predict all categories of GMSs. This model is based on the following fact: the total IMF B total can be used to trigger an alarm for GMSs, when sudden changes in total magnetic field B total occur. This is the first alarm condition for a storm's arrival. It is observed in the present study that the southward B z component of the IMF is an important factor for describing GMSs. A result of the paper is that the magnitude of B z is maximum neither during the initial phase (at the instant of the IP shock) nor during the main phase (at the instant of Disturbance storm time (Dst) minimum). It is seen in this study that there is a time delay between the maximum value of southward B z and the Dst minimum, and this time delay can be used in the prediction of the intensity of a magnetic storm two-three hours before the main phase of a GMS. A linear relation has been derived between the maximum value of the southward component of B z and the Dst, which is Dst = (−0.06) + (7.65) B z +t. Some auxiliary conditions should be fulfilled with this, for example the speed of the solar wind should, on average, be 350 km s −1 to 750 km s −1 , plasma β should be low and, most importantly, plasma temperature

Free-free and fixed base modal survey tests of the Space Station Common Module Prototype

Science.gov (United States)

Driskill, T. C.; Anderson, J. B.; Coleman, A. D.

1992-01-01

This paper describes the testing aspects and the problems encountered during the free-free and fixed base modal surveys completed on the original Space Station Common Module Prototype (CMP). The CMP is a 40-ft long by 14.5-ft diameter 'waffle-grid' cylinder built by the Boeing Company and housed at the Marshall Space Flight Center (MSFC) near Huntsville, AL. The CMP modal survey tests were conducted at MSFC by the Dynamics Test Branch. The free-free modal survey tests (June '90 to Sept. '90) included interface verification tests (IFVT), often referred to as impedance measurements, mass-additive testing and linearity studies. The fixed base modal survey tests (Feb. '91 to April '91), including linearity studies, were conducted in a fixture designed to constrain the CMP in 7 total degrees-of-freedom at five trunnion interfaces (two primary, two secondary, and the keel). The fixture also incorporated an airbag off-load system designed to alleviate the non-linear effects of friction in the primary and secondary trunnion interfaces. Numerous test configurations were performed with the objective of providing a modal data base for evaluating the various testing methodologies to verify dynamic finite element models used for input to coupled load analysis.

The Aalborg Survey / Part 3 - Interview Based Survey

DEFF Research Database (Denmark)

Harder, Henrik; Christensen, Cecilie Breinholm; Jensen, Maria Vestergaard

Background and purpose The Aalborg Survey consists of four independent parts: a web, GPS and an interview based survey and a literature study, which together form a consistent investigation and research into use of urban space, and specifically into young people’s use of urban space: what young...... people do in urban spaces, where they are in the urban spaces and when the young people are in the urban spaces. The answers to these questions form the framework and enable further academic discussions and conclusions in relation to the overall research project Diverse Urban Spaces (DUS). The primary......) and the research focus within the cluster of Mobility and Tracking Technologies (MoTT), AAU. Summary / Part 3 - Interview Based Survey The 3rd part of the DUS research project has been carried out during the fall of 2009 and the summer and fall of 2010 as an interview based survey of 18 selected participants (nine...

A statistical survey of heat input parameters into the cusp thermosphere

Science.gov (United States)

Moen, J. I.; Skjaeveland, A.; Carlson, H. C.

2017-12-01

Based on three winters of observational data, we present those ionosphere parameters deemed most critical to realistic space weather ionosphere and thermosphere representation and prediction, in regions impacted by variability in the cusp. The CHAMP spacecraft revealed large variability in cusp thermosphere densities, measuring frequent satellite drag enhancements, up to doublings. The community recognizes a clear need for more realistic representation of plasma flows and electron densities near the cusp. Existing average-value models produce order of magnitude errors in these parameters, resulting in large under estimations of predicted drag. We fill this knowledge gap with statistics-based specification of these key parameters over their range of observed values. The EISCAT Svalbard Radar (ESR) tracks plasma flow Vi , electron density Ne, and electron, ion temperatures Te, Ti , with consecutive 2-3 minute windshield-wipe scans of 1000x500 km areas. This allows mapping the maximum Ti of a large area within or near the cusp with high temporal resolution. In magnetic field-aligned mode the radar can measure high-resolution profiles of these plasma parameters. By deriving statistics for Ne and Ti , we enable derivation of thermosphere heating deposition under background and frictional-drag-dominated magnetic reconnection conditions. We separate our Ne and Ti profiles into quiescent and enhanced states, which are not closely correlated due to the spatial structure of the reconnection foot point. Use of our data-based parameter inputs can make order of magnitude corrections to input data driving thermosphere models, enabling removal of previous two fold drag errors.

Laser dimpling process parameters selection and optimization using surrogate-driven process capability space

Science.gov (United States)

Ozkat, Erkan Caner; Franciosa, Pasquale; Ceglarek, Dariusz

2017-08-01

Remote laser welding technology offers opportunities for high production throughput at a competitive cost. However, the remote laser welding process of zinc-coated sheet metal parts in lap joint configuration poses a challenge due to the difference between the melting temperature of the steel (∼1500 °C) and the vapourizing temperature of the zinc (∼907 °C). In fact, the zinc layer at the faying surface is vapourized and the vapour might be trapped within the melting pool leading to weld defects. Various solutions have been proposed to overcome this problem over the years. Among them, laser dimpling has been adopted by manufacturers because of its flexibility and effectiveness along with its cost advantages. In essence, the dimple works as a spacer between the two sheets in lap joint and allows the zinc vapour escape during welding process, thereby preventing weld defects. However, there is a lack of comprehensive characterization of dimpling process for effective implementation in real manufacturing system taking into consideration inherent changes in variability of process parameters. This paper introduces a methodology to develop (i) surrogate model for dimpling process characterization considering multiple-inputs (i.e. key control characteristics) and multiple-outputs (i.e. key performance indicators) system by conducting physical experimentation and using multivariate adaptive regression splines; (ii) process capability space (Cp-Space) based on the developed surrogate model that allows the estimation of a desired process fallout rate in the case of violation of process requirements in the presence of stochastic variation; and, (iii) selection and optimization of the process parameters based on the process capability space. The proposed methodology provides a unique capability to: (i) simulate the effect of process variation as generated by manufacturing process; (ii) model quality requirements with multiple and coupled quality requirements; and (iii

On the identification of multiple space dependent ionic parameters in cardiac electrophysiology modelling

Science.gov (United States)

Abidi, Yassine; Bellassoued, Mourad; Mahjoub, Moncef; Zemzemi, Nejib

2018-03-01

In this paper, we consider the inverse problem of space dependent multiple ionic parameters identification in cardiac electrophysiology modelling from a set of observations. We use the monodomain system known as a state-of-the-art model in cardiac electrophysiology and we consider a general Hodgkin-Huxley formalism to describe the ionic exchanges at the microscopic level. This formalism covers many physiological transmembrane potential models including those in cardiac electrophysiology. Our main result is the proof of the uniqueness and a Lipschitz stability estimate of ion channels conductance parameters based on some observations on an arbitrary subdomain. The key idea is a Carleman estimate for a parabolic operator with multiple coefficients and an ordinary differential equation system.

Moving to continuous facial expression space using the MPEG-4 facial definition parameter (FDP) set

Science.gov (United States)

Karpouzis, Kostas; Tsapatsoulis, Nicolas; Kollias, Stefanos D.

2000-06-01

Research in facial expression has concluded that at least six emotions, conveyed by human faces, are universally associated with distinct expressions. Sadness, anger, joy, fear, disgust and surprise are categories of expressions that are recognizable across cultures. In this work we form a relation between the description of the universal expressions and the MPEG-4 Facial Definition Parameter Set (FDP). We also investigate the relation between the movement of basic FDPs and the parameters that describe emotion-related words according to some classical psychological studies. In particular Whissel suggested that emotions are points in a space, which seem to occupy two dimensions: activation and evaluation. We show that some of the MPEG-4 Facial Animation Parameters (FAPs), approximated by the motion of the corresponding FDPs, can be combined by means of a fuzzy rule system to estimate the activation parameter. In this way variations of the six archetypal emotions can be achieved. Moreover, Plutchik concluded that emotion terms are unevenly distributed through the space defined by dimensions like Whissel's; instead they tend to form an approximately circular pattern, called 'emotion wheel,' modeled using an angular measure. The 'emotion wheel' can be defined as a reference for creating intermediate expressions from the universal ones, by interpolating the movement of dominant FDP points between neighboring basic expressions. By exploiting the relation between the movement of the basic FDP point and the activation and angular parameters we can model more emotions than the primary ones and achieve efficient recognition in video sequences.

Non-Abelian monopole in the parameter space of point-like interactions

International Nuclear Information System (INIS)

Ohya, Satoshi

2014-01-01

We study non-Abelian geometric phase in N=2 supersymmetric quantum mechanics for a free particle on a circle with two point-like interactions at antipodal points. We show that non-Abelian Berry’s connection is that of SU(2) magnetic monopole discovered by Moody, Shapere and Wilczek in the context of adiabatic decoupling limit of diatomic molecule. - Highlights: • Supersymmetric quantum mechanics is an ideal playground for studying geometric phase. • We determine the parameter space of supersymmetric point-like interactions. • Berry’s connection is given by a Wu–Yang-like magnetic monopole in SU(2) Yang–Mills

Exploiting Auto-Collimation for Real-Time Onboard Monitoring of Space Optical Camera Geometric Parameters

Science.gov (United States)

Liu, W.; Wang, H.; Liu, D.; Miu, Y.

2018-05-01

Precise geometric parameters are essential to ensure the positioning accuracy for space optical cameras. However, state-of-the-art onorbit calibration method inevitably suffers from long update cycle and poor timeliness performance. To this end, in this paper we exploit the optical auto-collimation principle and propose a real-time onboard calibration scheme for monitoring key geometric parameters. Specifically, in the proposed scheme, auto-collimation devices are first designed by installing collimated light sources, area-array CCDs, and prisms inside the satellite payload system. Through utilizing those devices, the changes in the geometric parameters are elegantly converted into changes in the spot image positions. The variation of geometric parameters can be derived via extracting and processing the spot images. An experimental platform is then set up to verify the feasibility and analyze the precision index of the proposed scheme. The experiment results demonstrate that it is feasible to apply the optical auto-collimation principle for real-time onboard monitoring.

Frequentist analysis of the parameter space of minimal supergravity

Energy Technology Data Exchange (ETDEWEB)

Buchmueller, O.; Colling, D. [Imperial College, London (United Kingdom). High Energy Physics Group; Cavanaugh, R. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Illinois Univ., Chicago, IL (US). Physics Dept.] (and others)

2010-12-15

We make a frequentist analysis of the parameter space of minimal supergravity (mSUGRA), in which, as well as the gaugino and scalar soft supersymmetry-breaking parameters being universal, there is a specific relation between the trilinear, bilinear and scalar supersymmetry-breaking parameters, A{sub 0}=B{sub 0}+m{sub 0}, and the gravitino mass is fixed by m{sub 3/2}=m{sub 0}. We also consider a more general model, in which the gravitino mass constraint is relaxed (the VCMSSM). We combine in the global likelihood function the experimental constraints from low-energy electroweak precision data, the anomalous magnetic moment of the muon, the lightest Higgs boson mass M{sub h}, B physics and the astrophysical cold dark matter density, assuming that the lightest supersymmetric particle (LSP) is a neutralino. In the VCMSSM, we find a preference for values of m{sub 1/2} and m{sub 0} similar to those found previously in frequentist analyses of the constrained MSSM (CMSSM) and a model with common non-universal Higgs masses (NUHM1). On the other hand, in mSUGRA we find two preferred regions: one with larger values of both m{sub 1/2} and m{sub 0} than in the VCMSSM, and one with large m{sub 0} but small m{sub 1/2}. We compare the probabilities of the frequentist fits in mSUGRA, the VCMSSM, the CMSSM and the NUHM1: the probability that mSUGRA is consistent with the present data is significantly less than in the other models. We also discuss the mSUGRA and VCMSSM predictions for sparticle masses and other observables, identifying potential signatures at the LHC and elsewhere. (orig.)

The MSSM Parameter Space with Non-Universal Higgs Masses

CERN Document Server

Ellis, Jonathan Richard; Santoso, Y; Ellis, John; Olive, Keith A.; Santoso, Yudi

2002-01-01

Without assuming that Higgs masses have the same values as other scalar masses at the input GUT scale, we combine constraints on the minimal supersymmetric extension of the Standard Model (MSSM) coming from the cold dark matter density with the limits from direct searches at accelerators such as LEP, indirect measurements such as b to s gamma decay and the anomalous magnetic moment of the muon. The requirement that Higgs masses-squared be positive at the GUT scale imposes important restrictions on the MSSM parameter space, as does the requirement that the LSP be neutral. We analyze the interplay of these constraints in the (mu, m_A), (mu, m_{1/2}), (m_{1/2}, m_0) and (m_A, tan beta) planes. These exhibit new features not seen in the corresponding planes in the constrained MSSM in which universality is extended to Higgs masses.

Application of separable parameter space techniques to multi-tracer PET compartment modeling

International Nuclear Information System (INIS)

Zhang, Jeff L; Michael Morey, A; Kadrmas, Dan J

2016-01-01

Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg–Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models. (paper)

Multiplicity distributions in impact parameter space

International Nuclear Information System (INIS)

Wakano, Masami

1976-01-01

A definition for the average multiplicity of pions as a function of momentum transfer and total energy in the high energy proton-proton collisions is proposed by using the n-pion production differential cross section with the given momentum transfer from a proton to other final products and the given energy of the latter. Contributions from nondiffractive and diffractive processes are formulated in a multi-Regge model. We define a relationship between impact parameter and momentum transfer in the sense of classical theory for inelastic processes and we obtain the average multiplicity of pions as a function of impact parameter and total energy from the corresponding quantity afore-mentioned. By comparing this quantity with the square root of the opaqueness at given impact parameter, we conclude that the overlap of localized constituents is important in determining the opaqueness at given impact parameter in a collision of two hadrons. (auth.)

Exploring the triplet parameters space to optimise the final focus of the FCC-hh

CERN Document Server

AUTHOR|(CDS)2141109; Abelleira, Jose; Seryi, Andrei; Cruz Alaniz, Emilia

2017-01-01

One of the main challenges when designing final focus systems of particle accelerators is maximising the beam stay clear in the strong quadrupole magnets of the inner triplet. Moreover it is desirable to keep the quadrupoles in the triplet as short as possible for space and costs reasons but also to reduce chromaticity and simplify corrections schemes. An algorithm that explores the triplet parameter space to optimise both these aspects was written. It uses thin lenses as a first approximation and MADX for more precise calculations. In cooperation with radiation studies, this algorithm was then applied to design an alternative triplet for the final focus of the Future Circular Collider (FCC-hh).

Academic Libraries, Facebook and MySpace, and Student Outreach: A Survey of Student Opinion

Science.gov (United States)

Connell, Ruth Sara

2009-01-01

This study surveyed 366 Valparaiso University freshmen to discover their feelings about librarians using Facebook and MySpace as outreach tools. The vast majority of respondents had online social network profiles. Most indicated that they would be accepting of library contact through those Web sites, but a sizable minority reacted negatively to…

Stellar parameters and H α line profile variability of Be stars in the BeSOS survey

Science.gov (United States)

Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M.

2018-03-01

The Be phenomenon is present in about 20 per cent of B-type stars. Be stars show variability on a broad range of time-scales, which in most cases is related to the presence of a circumstellar disc of variable size and structure. For this reason, a time-resolved survey is highly desirable in order to understand the mechanisms of disc formation, which are still poorly understood. In addition, a complete observational sample would improve the statistical significance of the study of stellar and disc parameters. The `Be Stars Observation Survey' (BeSOS) is a survey containing reduced spectra obtained using the Pontifica Universidad Católica High Echelle Resolution Optical Spectrograph (PUCHEROS) with a spectral resolution of 17 000 in the range 4260-7300 Å. BeSOS's main objective is to offer consistent spectroscopic and time-resolved data obtained with one instrument. The user can download or plot the data and obtain stellar parameters directly from the website. We also provide a star-by-star analysis based on photometric, spectroscopic and interferometric data, as well as general information about the whole BeSOS sample. Recently, BeSOS led to the discovery of a new Be star HD 42167 and facilitated study of the V/R variation of HD 35165 and HD 120324, the steady disc of HD 110335 and the Be shell status of HD 127972. Optical spectra used in this work, as well as the stellar parameters derived, are available online at http://besos.ifa.uv.cl.

Constraints on pre-big-bang parameter space from CMBR anisotropies

International Nuclear Information System (INIS)

Bozza, V.; Gasperini, M.; Giovannini, M.; Veneziano, G.

2003-01-01

The so-called curvaton mechanism--a way to convert isocurvature perturbations into adiabatic ones--is investigated both analytically and numerically in a pre-big-bang scenario where the role of the curvaton is played by a sufficiently massive Kalb-Ramond axion of superstring theory. When combined with observations of CMBR anisotropies at large and moderate angular scales, the present analysis allows us to constrain quite considerably the parameter space of the model: in particular, the initial displacement of the axion from the minimum of its potential and the rate of evolution of the compactification volume during pre-big-bang inflation. The combination of theoretical and experimental constraints favors a slightly blue spectrum of scalar perturbations, and/or a value of the string scale in the vicinity of the SUSY GUT scale

Constraints on pre-big bang parameter space from CMBR anisotropies

CERN Document Server

Bozza, Valerio; Giovannini, Massimo; Veneziano, Gabriele

2003-01-01

The so-called curvaton mechanism --a way to convert isocurvature perturbations into adiabatic ones-- is investigated both analytically and numerically in a pre-big bang scenario where the role of the curvaton is played by a sufficiently massive Kalb--Ramond axion of superstring theory. When combined with observations of CMBR anisotropies at large and moderate angular scales, the present analysis allows us to constrain quite considerably the parameter space of the model: in particular, the initial displacement of the axion from the minimum of its potential and the rate of evolution of the compactification volume during pre-big bang inflation. The combination of theoretical and experimental constraints favours a slightly blue spectrum of scalar perturbations, and/or a value of the string scale in the vicinity of the SUSY-GUT scale.

Robotic influence in the conceptual design of mechanical systems in space and vice versa - A survey

Science.gov (United States)

Sanger, George F.

1988-01-01

A survey of methods using robotic devices to construct structural elements in space is presented. Two approaches to robotic construction are considered: one in which the structural elements are designed using conventional aerospace techniques which tend to constrain the function aspects of robotics and one in which the structural elements are designed from the conceptual stage with built-in robotic features. Examples are presented of structural building concepts using robotics, including the construction of the SP-100 nuclear reactor power system, a multimirror large aperture IR space telescope concept, retrieval and repair in space, and the Flight Telerobotic Servicer.

A morphing technique for signal modelling in a multidimensional space of coupling parameters

CERN Document Server

The ATLAS collaboration

2015-01-01

This note describes a morphing method that produces signal models for fits to data in which both the affected event yields and kinematic distributions are simultaneously taken into account. The signal model is morphed in a continuous manner through the available multi-dimensional parameter space. Searches for deviations from Standard Model predictions for Higgs boson properties have so far used information either from event yields or kinematic distributions. The combined approach described here is expected to substantially enhance the sensitivity to beyond the Standard Model contributions.

The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

Science.gov (United States)

da Costa, Diogo Ricardo; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

2016-04-01

We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems.

Parameter space of general gauge mediation

International Nuclear Information System (INIS)

Rajaraman, Arvind; Shirman, Yuri; Smidt, Joseph; Yu, Felix

2009-01-01

We study a subspace of General Gauge Mediation (GGM) models which generalize models of gauge mediation. We find superpartner spectra that are markedly different from those of typical gauge and gaugino mediation scenarios. While typical gauge mediation predictions of either a neutralino or stau next-to-lightest supersymmetric particle (NLSP) are easily reproducible with the GGM parameters, chargino and sneutrino NLSPs are generic for many reasonable choices of GGM parameters.

Alternative analysis of airborne laser data collected within conventional multi-parameter airborne geophysical surveys

Science.gov (United States)

Ahl, Andreas; Supper, R.; Motschka, K.; Schattauer, I.

2010-05-01

For the interpretation of airborne gamma-ray spectrometry as well as airborne electromagnetics it is of great importance to determine the distance between the geophysical sensor and the ground surface. Since radar altimeters do not penetrate vegetation, laser altimeters became popular in airborne geophysics over the past years. Currently the airborne geophysical platform of the Geological Survey of Austria (GBA) is equipped with a Riegl LD90-3800VHS-FLP high resolution laser altimeter, measuring the distances according to the first and the last reflected pulse. The goal of the presented study was to explore the possibilities of deriving additional information about the survey area from the laser data and to determine the accuracy of such results. On one hand the difference between the arrival time of the first and the last reflected pulse can be used to determine the height of the vegetation. This parameter is for example important for the correction of damping effects on airborne gamma-ray measurements caused by vegetation. Moreover especially for groundwater studies at catchment scale, this parameter can also be applied to support the spatial assessment of evapotranspiration. In combination with the altitude above geoid, determined by a GPS receiver, a rough digital elevation model of the survey area can be derived from the laser altimetry. Based on a data set from a survey area in the northern part of Austria, close to the border with the Czech Republic, the reliability of such a digital elevation model and the calculated vegetation height was tested. In this study a mean deviation of -1.4m, with a standard deviation of ±3.4m, between the digital elevation model from Upper Austria (25m spatial resolution) and the determined elevation model was determined. We also found an obvious correlation between the calculated vegetation heights greater 15m and the mapped forest published by the ‘Department of Forest Inventory' of the ‘Federal Forest Office' of Austria

A nationwide Danish survey on the use of green spaces by people with mobility disabilities.

Science.gov (United States)

Stigsdotter, Ulrika K; Corazon, Sus Sola; Ekholm, Ola

2017-12-01

There is increasing awareness of the importance and health benefits of living near green spaces. Research usually focuses on the general population's use of green spaces and there has been little focus on the use of green spaces by specific groups, such as people with mobility disabilities. This represents a significant knowledge gap with regard to facilitating access to healthy green environments by all population groups. This study aims to provide knowledge of the use of green spaces by people with mobility disabilities. The study was based on data from the Danish Health and Morbidity Survey in 2005. The study participants consisted of 11,238 adult Danes, 383 of whom reported mobility disabilities, meaning that they were dependent on assistive devices for walking or moving around. Multiple logistic regression analysis was used to investigate the association between mobility disability and use of green spaces. The results show that respondents who reported mobility disabilities visited green spaces less often than respondents without mobility disabilities. The severity of the mobility disability was associated with the frequency of visits. Frequency of visits was also related to the respondents' health-related quality of life status. These results highlight the need for further research into the constraints faced by people with mobility disabilities with regard to visiting green spaces.

Relationship between anthropometric parameters and open angle glaucoma: The Korea National Health and Nutrition Examination Survey.

Directory of Open Access Journals (Sweden)

Jae Yeun Lee

Full Text Available To evaluate the relationships between open-angle glaucoma (OAG and various anthropometric measurements.Korea National Health and Nutrition Examination Survey (KNHANES, a population-based cross-sectional study using a complex, stratified, multistage, probability-cluster survey.A total of 5,255 participants including 247 glaucoma patients, aged ≥ 19 years were included from the KNHANES V database. Glaucoma diagnosis was based on International Society of Geographical and Epidemiological Ophthalmology criteria. Various anthropometric data regarding obesity were analyzed including body mass index (BMI, total body fat mass, total body muscle mass (lean body mass, non-bone lean body mass, and appendicular skeletal muscle (ASM mass, and waist circumference (WC. The differences in OAG prevalence with respect to anthropometric parameter quartiles were examined.In males, the multivariate general linear model adjusted for age, alcohol, smoking, exercise, systemic hypertension, diabetes, and intraocular pressure (IOP showed the quartiles for the anthropometric parameters BMI, fat mass/weight ratio and fat mass/muscle mass ratio were negatively associated with OAG. However, muscle mass parameter/BMI ratio was significantly positively associated with OAG (P for trend<0.05. In females, height and fat mass/BMI showed a significant relationship with the risk of OAG. (P value<0.05.In the present study, high fat mass was associated with low OAG risk. Body composition seemed to affect the prevalence of OAG, but further evaluation is needed.

Relationship between anthropometric parameters and open angle glaucoma: The Korea National Health and Nutrition Examination Survey.

Science.gov (United States)

Lee, Jae Yeun; Kim, Tae-Woo; Kim, Hyun Tae; Lee, Mi Yeon; Min, Hye Won; Won, Yu Sam; Kwon, Hyun Seok; Park, Ki Ho; Kim, Joon Mo

2017-01-01

To evaluate the relationships between open-angle glaucoma (OAG) and various anthropometric measurements. Korea National Health and Nutrition Examination Survey (KNHANES), a population-based cross-sectional study using a complex, stratified, multistage, probability-cluster survey. A total of 5,255 participants including 247 glaucoma patients, aged ≥ 19 years were included from the KNHANES V database. Glaucoma diagnosis was based on International Society of Geographical and Epidemiological Ophthalmology criteria. Various anthropometric data regarding obesity were analyzed including body mass index (BMI), total body fat mass, total body muscle mass (lean body mass, non-bone lean body mass, and appendicular skeletal muscle (ASM) mass), and waist circumference (WC). The differences in OAG prevalence with respect to anthropometric parameter quartiles were examined. In males, the multivariate general linear model adjusted for age, alcohol, smoking, exercise, systemic hypertension, diabetes, and intraocular pressure (IOP) showed the quartiles for the anthropometric parameters BMI, fat mass/weight ratio and fat mass/muscle mass ratio were negatively associated with OAG. However, muscle mass parameter/BMI ratio was significantly positively associated with OAG (P for trend<0.05). In females, height and fat mass/BMI showed a significant relationship with the risk of OAG. (P value<0.05). In the present study, high fat mass was associated with low OAG risk. Body composition seemed to affect the prevalence of OAG, but further evaluation is needed.

CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY-THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

NARCIS (Netherlands)

Koekemoer, Anton M.; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; Lotz, Jennifer M.; Lucas, Ray A.; McGrath, Elizabeth J.; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G.; Rodney, Steve A.; Strolger, Louis; Casertano, Stefano; Castellano, Marco; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Cassata, Paolo; Challis, Peter J.; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dave, Romeel; de Mello, Duilia F.; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Frazer, Chris; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G.; Haeussler, Boris; Herrington, Jessica; Hopkins, Philip F.; Huang, Jia-Sheng; Jha, Saurabh W.; Johnson, Andrew; Kartaltepe, Jeyhan S.; Khostovan, Ali A.; Kirshner, Robert P.; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J.; McIntosh, Daniel H.; McLure, Ross J.; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Nielsen, Jennifer L.; Niemi, Sami; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R.; Wandro, Pat; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S.

2011-01-01

This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z approximate to 1.5-8, and to study

Application of parameters space analysis tools for empirical model validation

Energy Technology Data Exchange (ETDEWEB)

Paloma del Barrio, E. [LEPT-ENSAM UMR 8508, Talence (France); Guyon, G. [Electricite de France, Moret-sur-Loing (France)

2004-01-01

A new methodology for empirical model validation has been proposed in the framework of the Task 22 (Building Energy Analysis Tools) of the International Energy Agency. It involves two main steps: checking model validity and diagnosis. Both steps, as well as the underlying methods, have been presented in the first part of the paper. In this part, they are applied for testing modelling hypothesis in the framework of the thermal analysis of an actual building. Sensitivity analysis tools have been first used to identify the parts of the model that can be really tested on the available data. A preliminary diagnosis is then supplied by principal components analysis. Useful information for model behaviour improvement has been finally obtained by optimisation techniques. This example of application shows how model parameters space analysis is a powerful tool for empirical validation. In particular, diagnosis possibilities are largely increased in comparison with residuals analysis techniques. (author)

Wide Field Radio Transient Surveys

Science.gov (United States)

Bower, Geoffrey

2011-04-01

The time domain of the radio wavelength sky has been only sparsely explored. Nevertheless, serendipitous discovery and results from limited surveys indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients and coherent pulses from brown dwarfs. Additionally, archival studies have revealed an unknown class of radio transients without radio, optical, or high-energy hosts. The new generation of centimeter-wave radio telescopes such as the Allen Telescope Array (ATA) will exploit wide fields of view and flexible digital signal processing to systematically explore radio transient parameter space, as well as lay the scientific and technical foundation for the Square Kilometer Array. Known unknowns that will be the target of future transient surveys include orphan gamma-ray burst afterglows, radio supernovae, tidally-disrupted stars, flare stars, and magnetars. While probing the variable sky, these surveys will also provide unprecedented information on the static radio sky. I will present results from three large ATA surveys (the Fly's Eye survey, the ATA Twenty CM Survey (ATATS), and the Pi GHz Survey (PiGSS)) and several small ATA transient searches. Finally, I will discuss the landscape and opportunities for future instruments at centimeter wavelengths.

Space Discovery: Teaching with Space. Evaluation: Summer, Fall 1998 Programs

Science.gov (United States)

Ewell, Bob

1998-01-01

This is the final report of the 1998 NASA-sponsored evaluation of the effectiveness of the United States Space Foundation's five-day Space Discovery Standard Graduate Course (Living and Working in Space), the five-day Space Discovery Advanced Graduate Course (Advanced Technology and Biomedical Research), the five-day introductory course Aviation and Space Basics all conducted during the summer of 1998, and the Teaching with Space two-day Inservice program. The purpose of the program is to motivate and equip K- 12 teachers to use proven student-attracting space and technology concepts to support standard curriculum. These programs support the America 2000 National Educational Goals, encouraging more students to stay in school, increase in competence, and have a better opportunity to be attracted to math and science. The 1998 research program continues the comprehensive evaluation begun in 1992, this year studying five summer five-day sessions and five Inservice programs offered during the Fall of 1998 in California, Colorado, New York, and Virginia. A comprehensive research design by Dr. Robert Ewell of Creative Solutions and Dr. Darwyn Linder of Arizona State University evaluated the effectiveness of various areas of the program and its applicability on diverse groups. Preliminary research methodology was a set of survey instruments administered after the courses, and another to be sent in April-4-5 months following the last inservice involved in this study. This year, we have departed from this evaluation design in two ways. First, the five-day programs used NASA's new EDCATS on-line system and associated survey rather than the Linder/Ewell instruments. The Inservice programs were evaluated using the previously developed survey adapted for Inservice programs. Second, we did not do a follow-on survey of the teachers after they had been in the field as we have done in the past. Therefore, this evaluation captures only the reactions of the teachers to the programs

The Aalborg Survey / Part 1 - Web Based Survey

DEFF Research Database (Denmark)

Harder, Henrik; Christensen, Cecilie Breinholm

Background and purpose The Aalborg Survey consists of four independent parts: a web, GPS and an interview based survey and a literature study, which together form a consistent investigation and research into use of urban space, and specifically into young people’s use of urban space: what young......) and the research focus within the cluster of Mobility and Tracking Technologies (MoTT), AAU. Summary / Part 1 Web Base Survey The 1st part of the research project Diverse Urban Spaces (DUS) has been carried out during the period from December 1st 2007 to February 1st 2008 as a Web Based Survey of the 27.040 gross...... [statistikbanken.dk, a] young people aged 14-23 living in Aalborg Municipality in 2008. The web based questionnaire has been distributed among the group of young people studying at upper secondary schools in Aalborg, i.e. 7.680 young people [statistikbanken.dk, b]. The resulting data from those respondents who...

ASPCAP: THE APOGEE STELLAR PARAMETER AND CHEMICAL ABUNDANCES PIPELINE

Energy Technology Data Exchange (ETDEWEB)

García Pérez, Ana E.; Majewski, Steven R.; Shane, Neville; Sobeck, Jennifer; Troup, Nicholas [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Prieto, Carlos Allende; Carrera, Ricardo; García-Hernández, D. A.; Zamora, Olga [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Holtzman, Jon A. [New Mexico State University, Las Cruces, NM 88003 (United States); Shetrone, Matthew [University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734 (United States); Mészáros, Szabolcs [ELTE Gothard Astrophysical Observatory, H-9704 Szombathely, Szent Imre Herceg St. 112 (Hungary); Bizyaev, Dmitry [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Cunha, Katia [Observatório Nacional, São Cristóvão, Rio de Janeiro (Brazil); Johnson, Jennifer A.; Weinberg, David H. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Nidever, David L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Schiavon, Ricardo P. [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, Wirral CH41 1LD (United Kingdom); Smith, Verne V. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Bovy, Jo, E-mail: agp@iac.es [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); and others

2016-06-01

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution ( R  ≈ 22,500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using χ {sup 2} minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.

ASPCAP: The APOGEE Stellar Parameter and Chemical Abundances Pipeline

Science.gov (United States)

García Pérez, Ana E.; Allende Prieto, Carlos; Holtzman, Jon A.; Shetrone, Matthew; Mészáros, Szabolcs; Bizyaev, Dmitry; Carrera, Ricardo; Cunha, Katia; García-Hernández, D. A.; Johnson, Jennifer A.; Majewski, Steven R.; Nidever, David L.; Schiavon, Ricardo P.; Shane, Neville; Smith, Verne V.; Sobeck, Jennifer; Troup, Nicholas; Zamora, Olga; Weinberg, David H.; Bovy, Jo; Eisenstein, Daniel J.; Feuillet, Diane; Frinchaboy, Peter M.; Hayden, Michael R.; Hearty, Fred R.; Nguyen, Duy C.; O'Connell, Robert W.; Pinsonneault, Marc H.; Wilson, John C.; Zasowski, Gail

2016-06-01

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R ≈ 22,500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using χ2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.

Estimating mutation parameters, population history and genealogy simultaneously from temporally spaced sequence data.

Science.gov (United States)

Drummond, Alexei J; Nicholls, Geoff K; Rodrigo, Allen G; Solomon, Wiremu

2002-07-01

Molecular sequences obtained at different sampling times from populations of rapidly evolving pathogens and from ancient subfossil and fossil sources are increasingly available with modern sequencing technology. Here, we present a Bayesian statistical inference approach to the joint estimation of mutation rate and population size that incorporates the uncertainty in the genealogy of such temporally spaced sequences by using Markov chain Monte Carlo (MCMC) integration. The Kingman coalescent model is used to describe the time structure of the ancestral tree. We recover information about the unknown true ancestral coalescent tree, population size, and the overall mutation rate from temporally spaced data, that is, from nucleotide sequences gathered at different times, from different individuals, in an evolving haploid population. We briefly discuss the methodological implications and show what can be inferred, in various practically relevant states of prior knowledge. We develop extensions for exponentially growing population size and joint estimation of substitution model parameters. We illustrate some of the important features of this approach on a genealogy of HIV-1 envelope (env) partial sequences.

Probing the parameter space of HD 49933: A comparison between global and local methods

Energy Technology Data Exchange (ETDEWEB)

Creevey, O L [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Bazot, M, E-mail: orlagh@iac.es, E-mail: bazot@astro.up.pt [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)

2011-01-01

We present two independent methods for studying the global stellar parameter space (mass M, age, chemical composition X{sub 0}, Z{sub 0}) of HD 49933 with seismic data. Using a local minimization and an MCMC algorithm, we obtain consistent results for the determination of the stellar properties: M 1.1-1.2 M{sub sun} Age {approx} 3.0 Gyr, Z{sub 0} {approx} 0.008. A description of the error ellipses can be defined using Singular Value Decomposition techniques, and this is validated by comparing the errors with those from the MCMC method.

A self-organizing state-space-model approach for parameter estimation in hodgkin-huxley-type models of single neurons.

Directory of Open Access Journals (Sweden)

Dimitrios V Vavoulis

Full Text Available Traditional approaches to the problem of parameter estimation in biophysical models of neurons and neural networks usually adopt a global search algorithm (for example, an evolutionary algorithm, often in combination with a local search method (such as gradient descent in order to minimize the value of a cost function, which measures the discrepancy between various features of the available experimental data and model output. In this study, we approach the problem of parameter estimation in conductance-based models of single neurons from a different perspective. By adopting a hidden-dynamical-systems formalism, we expressed parameter estimation as an inference problem in these systems, which can then be tackled using a range of well-established statistical inference methods. The particular method we used was Kitagawa's self-organizing state-space model, which was applied on a number of Hodgkin-Huxley-type models using simulated or actual electrophysiological data. We showed that the algorithm can be used to estimate a large number of parameters, including maximal conductances, reversal potentials, kinetics of ionic currents, measurement and intrinsic noise, based on low-dimensional experimental data and sufficiently informative priors in the form of pre-defined constraints imposed on model parameters. The algorithm remained operational even when very noisy experimental data were used. Importantly, by combining the self-organizing state-space model with an adaptive sampling algorithm akin to the Covariance Matrix Adaptation Evolution Strategy, we achieved a significant reduction in the variance of parameter estimates. The algorithm did not require the explicit formulation of a cost function and it was straightforward to apply on compartmental models and multiple data sets. Overall, the proposed methodology is particularly suitable for resolving high-dimensional inference problems based on noisy electrophysiological data and, therefore, a

Study and survey of assembling parameters to a radioactive source production laboratory used to verify equipment

International Nuclear Information System (INIS)

Gauglitz, Erica; Nagatomy, Helio Rissei; Moura, Eduardo S.; Zeituni, Carlos Alberto; Hilario, Katia A. Fonseca; Rostelato, Maria Elisa C.M.; Karam Junior, Dib

2009-01-01

This paper presents the survey of parameters for the installation and implementation of a laboratory for radioactive sources production at immobilized resin. These sources are used in nuclear medicine for verification of dose calibrators, as the standard guidelines of the National Commission of Nuclear CNEN-NE-3.05 'Radioprotection and safety requirements for nuclear medicine services.' The radioisotopes used for this purpose are: Co-57, Cs-137 and Ba-133, with activities of 185 MBq, 9.3 MBq and 5.4 MBq, respectively. The parameters for the assembly of the laboratory shall be defined according to guidelines that guide the deployment of radiochemical laboratories and standards of the National Commission of Nuclear Energy. (author)

Study and survey of assembling parameters to a radioactive source production laboratory used to verify equipment

Energy Technology Data Exchange (ETDEWEB)

Gauglitz, Erica; Nagatomy, Helio Rissei; Moura, Eduardo S.; Zeituni, Carlos Alberto; Hilario, Katia A. Fonseca; Rostelato, Maria Elisa C.M., E-mail: egauglitz@ipen.b, E-mail: elisaros@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Karam Junior, Dib, E-mail: dib.karan@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Escola de Artes, Ciencias e Humanidades

2009-07-01

This paper presents the survey of parameters for the installation and implementation of a laboratory for radioactive sources production at immobilized resin. These sources are used in nuclear medicine for verification of dose calibrators, as the standard guidelines of the National Commission of Nuclear CNEN-NE-3.05 'Radioprotection and safety requirements for nuclear medicine services.' The radioisotopes used for this purpose are: Co-57, Cs-137 and Ba-133, with activities of 185 MBq, 9.3 MBq and 5.4 MBq, respectively. The parameters for the assembly of the laboratory shall be defined according to guidelines that guide the deployment of radiochemical laboratories and standards of the National Commission of Nuclear Energy. (author)

3D-HST: A Wide-field Grism Spectroscopic Survey with the Hubble Space Telescope

Science.gov (United States)

Brammer, Gabriel B.; van Dokkum, Pieter G.; Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Rix, Hans-Walter; Skelton, Rosalind E.; Kriek, Mariska; Nelson, Erica; Schmidt, Kasper B.; Bezanson, Rachel; da Cunha, Elisabete; Erb, Dawn K.; Fan, Xiaohui; Förster Schreiber, Natascha; Illingworth, Garth D.; Labbé, Ivo; Leja, Joel; Lundgren, Britt; Magee, Dan; Marchesini, Danilo; McCarthy, Patrick; Momcheva, Ivelina; Muzzin, Adam; Quadri, Ryan; Steidel, Charles C.; Tal, Tomer; Wake, David; Whitaker, Katherine E.; Williams, Anna

2012-06-01

We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for a sample of ~7000 galaxies at 1 < z < 3.5, the epoch when ~60% of all star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. 3D-HST will cover three quarters (625 arcmin2) of the CANDELS Treasury survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of ~5 per resolution element at H 140 ~ 23.1 and a 5σ emission-line sensitivity of ~5 × 10-17 erg s-1 cm-2 for typical objects, improving by a factor of ~2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1 to 1.6 μm at a spatial resolution of ~0farcs13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary reduction and analysis of the grism observations, including emission-line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of σ(z) = 0.0034(1 + z), or σ(v) ≈ 1000 km s-1. We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z = 4.7, quiescent galaxies at z ~ 2, and the most distant T-type brown dwarf star known. The combination of the CANDELS and 3D-HST surveys will provide the definitive imaging and spectroscopic data set for studies of the 1 < z < 3.5 universe until the launch of the James Webb Space

Moduli space of Calabi-Yau manifolds

International Nuclear Information System (INIS)

Candelas, P.; De la Ossa, X.C.

1991-01-01

We present an accessible account of the local geometry of the parameter space of Calabi-Yau manifolds. It is shown that the parameter space decomposes, at least locally, into a product with the space of parameters of the complex structure as one factor and a complex extension of the parameter space of the Kaehler class as the other. It is also shown that each of these spaces is itself a Kaehler manifold and is moreover a Kaehler manifold of restricted type. There is a remarkable symmetry in the intrinsic structures of the two parameter spaces and the relevance of this to the conjectured existence of mirror manifolds is discussed. The two parameter spaces behave differently with respect to modular transformations and it is argued that the role of quantum corrections is to restore the symmetry between the two types of parameters so as to enforce modular invariance. (orig.)

Tree survey and allometric models for tiger bush in northern Senegal and comparison with tree parameters derived from high resolution satellite data

DEFF Research Database (Denmark)

Rasmussen, Mads Olander; Goettsche, Frank-M.; Diop, Doudou

2011-01-01

A tree survey and an analysis of high resolution satellite data were performed to characterise the woody vegetation within a 10 x 10 km(2) area around a site located close to the town of Dahra in the semiarid northern part of Senegal. The surveyed parameters were tree species, height, tree crown...

Gaia, an all-sky survey for standard photometry

Science.gov (United States)

Carrasco, J. M.; Weiler, M.; Jordi, C.; Fabricius, C.

2017-03-01

Gaia ESA's space mission (launched in 2013) includes two low resolution spectroscopic instruments (one in the blue, BP, and another in the red, RP, wavelength domains) to classify and derive the astrophysical parameters of the observed sources. As it is well known, Gaia is a full-sky unbiased survey down to about 20th magnitude. The scanning law yields a rather uniform coverage of the sky over the full extent (a minimum of 5 years) of the mission. Gaia data reduction is a global one over the full mission. Both sky coverage and data reduction strategy ensure an unprecedented all-sky homogeneous spectrophotometric survey. Certainly, that survey is of interest for current and future on-ground and space projects, like LSST, PLATO, EUCLID and J-PAS/J-PLUS among others. These projects will benefit from the large amount (more than one billion) and wide variety of objects observed by Gaia with good quality spectrophotometry. Synthetic photometry derived from Gaia spectrophotometry for any passband can be used to expand the set of standard sources for these new instruments to come. In the current Gaia data release scenario, BP/RP spectrophotometric data will be available in the third release (in 2018, TBC). Current preliminary results allow us to estimate the precision of synthetic photometry derived from the Gaia data. This already allows the preparation of the on-going and future surveys and space missions. We discuss here the exploitation of the Gaia spectrophotometry as standard reference due to its full-sky coverage and its expected photometric uncertainties derived from the low resolution Gaia spectra.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 2: Literature surveys of critical Space Shuttle main engine components

Science.gov (United States)

Rajagopal, K. R.

1992-01-01

The technical effort and computer code development is summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis. Volume 2 is a summary of critical SSME components.

Virtual walks in spin space: A study in a family of two-parameter models

Science.gov (United States)

Mullick, Pratik; Sen, Parongama

2018-05-01

We investigate the dynamics of classical spins mapped as walkers in a virtual "spin" space using a generalized two-parameter family of spin models characterized by parameters y and z [de Oliveira et al., J. Phys. A 26, 2317 (1993), 10.1088/0305-4470/26/10/006]. The behavior of S (x ,t ) , the probability that the walker is at position x at time t , is studied in detail. In general S (x ,t ) ˜t-αf (x /tα) with α ≃1 or 0.5 at large times depending on the parameters. In particular, S (x ,t ) for the point y =1 ,z =0.5 corresponding to the Voter model shows a crossover in time; associated with this crossover, two timescales can be defined which vary with the system size L as L2logL . We also show that as the Voter model point is approached from the disordered regions along different directions, the width of the Gaussian distribution S (x ,t ) diverges in a power law manner with different exponents. For the majority Voter case, the results indicate that the the virtual walk can detect the phase transition perhaps more efficiently compared to other nonequilibrium methods.

Exploitation of ISAR Imagery in Euler Parameter Space

National Research Council Canada - National Science Library

Baird, Christopher; Kersey, W. T; Giles, R; Nixon, W. E

2005-01-01

.... The Euler parameters have potential value in target classification but have historically met with limited success due to ambiguities that arise in decomposition as well as the parameters' sensitivity...

Joint cosmic microwave background and weak lensing analysis: constraints on cosmological parameters.

Science.gov (United States)

Contaldi, Carlo R; Hoekstra, Henk; Lewis, Antony

2003-06-06

We use cosmic microwave background (CMB) observations together with the red-sequence cluster survey weak lensing results to derive constraints on a range of cosmological parameters. This particular choice of observations is motivated by their robust physical interpretation and complementarity. Our combined analysis, including a weak nucleosynthesis constraint, yields accurate determinations of a number of parameters including the amplitude of fluctuations sigma(8)=0.89+/-0.05 and matter density Omega(m)=0.30+/-0.03. We also find a value for the Hubble parameter of H(0)=70+/-3 km s(-1) Mpc(-1), in good agreement with the Hubble Space Telescope key-project result. We conclude that the combination of CMB and weak lensing data provides some of the most powerful constraints available in cosmology today.

A Markov Chain Monte Carlo version of the genetic algorithm Differential Evolution: easy Bayesian computing for real parameter spaces

NARCIS (Netherlands)

Braak, ter C.J.F.

2006-01-01

Differential Evolution (DE) is a simple genetic algorithm for numerical optimization in real parameter spaces. In a statistical context one would not just want the optimum but also its uncertainty. The uncertainty distribution can be obtained by a Bayesian analysis (after specifying prior and

Impact of large-scale tides on cosmological distortions via redshift-space power spectrum

Science.gov (United States)

Akitsu, Kazuyuki; Takada, Masahiro

2018-03-01

Although large-scale perturbations beyond a finite-volume survey region are not direct observables, these affect measurements of clustering statistics of small-scale (subsurvey) perturbations in large-scale structure, compared with the ensemble average, via the mode-coupling effect. In this paper we show that a large-scale tide induced by scalar perturbations causes apparent anisotropic distortions in the redshift-space power spectrum of galaxies in a way depending on an alignment between the tide, wave vector of small-scale modes and line-of-sight direction. Using the perturbation theory of structure formation, we derive a response function of the redshift-space power spectrum to large-scale tide. We then investigate the impact of large-scale tide on estimation of cosmological distances and the redshift-space distortion parameter via the measured redshift-space power spectrum for a hypothetical large-volume survey, based on the Fisher matrix formalism. To do this, we treat the large-scale tide as a signal, rather than an additional source of the statistical errors, and show that a degradation in the parameter is restored if we can employ the prior on the rms amplitude expected for the standard cold dark matter (CDM) model. We also discuss whether the large-scale tide can be constrained at an accuracy better than the CDM prediction, if the effects up to a larger wave number in the nonlinear regime can be included.

The one-parameter subgroup of rotations generated by spin transformations in three-dimensional real space

International Nuclear Information System (INIS)

Gazoya, E.D.K.; Prempeh, E.; Banini, G.K.

2015-01-01

The relationship between the spin transformations of the special linear group of order 2, SL (2, C) and the aggregate SO(3) of the three-dimensional pure rotations when considered as a group in itself (and not as a subgroup of the Lorentz group), is investigated. It is shown, by the spinor map X - → AXA ct which is all action of SL(2. C) on the space of Hermitian matrices, that the one- parameter subgroup of rotations generated are precisely those of angles which are multiples 2π. (au)

Derivation of Delaware Bay tidal parameters from space shuttle photography

International Nuclear Information System (INIS)

Zheng, Quanan; Yan, Xiaohai; Klemas, V.

1993-01-01

The tide-related parameters of the Delaware Bay are derived from space shuttle time-series photographs. The water areas in the bay are measured from interpretation maps of the photographs with a CALCOMP 9100 digitizer and ERDAS Image Processing System. The corresponding tidal levels are calculated using the exposure time annotated on the photographs. From these data, an approximate function relating the water area to the tidal level at a reference point is determined. Based on the function, the water areas of the Delaware Bay at mean high water (MHW) and mean low water (MLW), below 0 m, and for the tidal zone are inferred. With MHW and MLW areas and the mean tidal range, the authors calculate the tidal influx of the Delaware Bay, which is 2.76 x 1O 9 m 3 . Furthermore, the velocity of flood tide at the bay mouth is determined using the tidal flux and an integral of the velocity distribution function at the cross section between Cape Henlopen and Cape May. The result is 132 cm/s, which compares well with the data on tidal current charts

Thermal comfort in urban green spaces: a survey on a Dutch university campus.

Science.gov (United States)

Wang, Yafei; de Groot, Rudolf; Bakker, Frank; Wörtche, Heinrich; Leemans, Rik

2017-01-01

To better understand the influence of urban green infrastructure (UGI) on outdoor human thermal comfort, a survey and physical measurements were performed at the campus of the University of Groningen, The Netherlands, in spring and summer 2015. Three hundred eighty-nine respondents were interviewed in five different green spaces. We aimed to analyze people's thermal comfort perception and preference in outdoor urban green spaces, and to specify the combined effects between the thermal environmental and personal factors. The results imply that non-physical environmental and subjective factors (e.g., natural view, quiet environment, and emotional background) were more important in perceiving comfort than the actual thermal conditions. By applying a linear regression and probit analysis, the comfort temperature was found to be 22.2 °C and the preferred temperature was at a surprisingly high 35.7 °C. This can be explained by the observation that most respondents, who live in temperate regions, have a natural tendency to describe their preferred state as "warmer" even when feeling "warm" already. Using the Kruskal-Wallis H test, the four significant factors influencing thermal comfort were people's exposure time in green spaces, previous thermal environment and activity, and their thermal history. However, the effect of thermal history needs further investigation due to the unequal sample sizes of respondents from different climate regions. By providing evidence for the role of the objective and subjective factors on human thermal comfort, the relationship between UGI, microclimate, and thermal comfort can assist urban planning to make better use of green spaces for microclimate regulation.

Synthesizing exoplanet demographics from radial velocity and microlensing surveys. I. Methodology

International Nuclear Information System (INIS)

Clanton, Christian; Gaudi, B. Scott

2014-01-01

Motivated by the order of magnitude difference in the frequency of giant planets orbiting M dwarfs inferred by microlensing and radial velocity (RV) surveys, we present a method for comparing the statistical constraints on exoplanet demographics inferred from these methods. We first derive the mapping from the observable parameters of a microlensing-detected planet to those of an analogous planet orbiting an RV-monitored star. Using this mapping, we predict the distribution of RV observables for the planet population inferred from microlensing surveys, taking care to adopt reasonable priors for, and properly marginalize over, the unknown physical parameters of microlensing-detected systems. Finally, we use simple estimates of the detection limits for a fiducial RV survey to predict the number and properties of analogs of the microlensing planet population such an RV survey should detect. We find that RV and microlensing surveys have some overlap, specifically for super-Jupiter mass planets (m p ≳ 1 M Jup ) with periods between ∼3-10 yr. However, the steeply falling planetary mass function inferred from microlensing implies that, in this region of overlap, RV surveys should infer a much smaller frequency than the overall giant planet frequency (m p ≳ 0.1 M Jup ) inferred by microlensing. Our analysis demonstrates that it is possible to statistically compare and synthesize data sets from multiple exoplanet detection techniques in order to infer exoplanet demographics over wider regions of parameter space than are accessible to individual methods. In a companion paper, we apply our methodology to several representative microlensing and RV surveys to derive the frequency of planets around M dwarfs with orbits of ≲ 30 yr.

Cosmological parameters from CMB and other data: A Monte Carlo approach

International Nuclear Information System (INIS)

Lewis, Antony; Bridle, Sarah

2002-01-01

We present a fast Markov chain Monte Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent cosmic microwave background (CMB) experiments and provide parameter constraints, including σ 8 , from the CMB independent of other data. We next combine data from the CMB, HST Key Project, 2dF galaxy redshift survey, supernovae type Ia and big-bang nucleosynthesis. The Monte Carlo method allows the rapid investigation of a large number of parameters, and we present results from 6 and 9 parameter analyses of flat models, and an 11 parameter analysis of non-flat models. Our results include constraints on the neutrino mass (m ν < or approx. 3 eV), equation of state of the dark energy, and the tensor amplitude, as well as demonstrating the effect of additional parameters on the base parameter constraints. In a series of appendixes we describe the many uses of importance sampling, including computing results from new data and accuracy correction of results generated from an approximate method. We also discuss the different ways of converting parameter samples to parameter constraints, the effect of the prior, assess the goodness of fit and consistency, and describe the use of analytic marginalization over normalization parameters

Survey on the parameters influencing X-ray picture quality

International Nuclear Information System (INIS)

Stender, H.S.

1985-01-01

Survey on factors influencing X-ray picture quality: 1) identification of patient and imaged body part. 2) Object properties - thickness, density, built; spatial expansion and arrangement of anatomical parts; object parts in a homogenic and an inhomogenic environment; object movements. 3) Examination technique - matching to medical issue; positioning and adjustment; projection; picture format in keeping with the medical issue; object-related fade-in; distance ratios; contrast medium distribution or deposition; compression. 4) Technical factors of picture production - radiation quality tube voltage; reproducible mAs and mR/mAs; automatic exposure equipment; focal spot size; scattered radiation grid; image intensifier and indirect radiography system; exposure time, dose-to-exposure-time ratio; film-screen combination; cassette with uniform pressure contact; film processing system; radiation safety and light safety. 5) Physical imaging parameters - mean optical density; resolution capacity; contrast reproduction; noise; modulation transmission function. 6) Perceptible picture properties - luminance density; picture contrast; recognizability of details; impression of grain structure; blurred picture structure; visually conspicuous elements. 7) Requirements on picture viewing - viewing device with high luminance density and equalized illumination; possible modification of brilliance; possible fade-in operations and prevention of ambient glare; spot light with iris diaphragm; possible viewing by magnifying lens; selection of correct viewing distances; repeated picture viewing or evaluation by two or more viewers. (orig./HP) [de

Classical algorithms for automated parameter-search methods in compartmental neural models - A critical survey based on simulations using neuron

International Nuclear Information System (INIS)

Mutihac, R.; Mutihac, R.C.; Cicuttin, A.

2001-09-01

gradient-descent techniques are adequate if the parameter space is low-dimensional, relatively smooth, and has a few local minima (e.g., parameterizing single-neuron compartmental models). Only the fast algorithms and/or a decent (low) number of model parameters are candidates for automated parameter search because of practical reasons. Eventually, the size of the parameter space may be reduced and/or parallel supercomputers may be used. Data overfitting may negatively affect the generalization ability of the model. Bayesian methods include Occam's factor, which set the preference for simpler models. Proliferation of (neural) models raises the question of rigorous criteria for comparing the overall performance of various models designed to match the same type of data. Bayesian methods provide the best framework to assess the neural models quantitatively. Paradoxically, parameter-search methods may sometimes be more useful when they fail by discarding unrealistic mechanisms used in the model design, rather than fitting experimental data to an alleged model

Preliminary study of environmental parameters associated with the feasibility of a polygeneration plant at Kennedy Space Center

International Nuclear Information System (INIS)

Barnes, G.D.

1982-01-01

The feasibility of a polygeneration plant at Kennedy Space Center was studied. Liquid hydrogen and gaseous nitrogen are the two principal products in consideration. Environmental parameters (air quality, water quality, biological diversity and hazardous waste disposal) necessary for the feasibility study were investigated. A National Environmental Policy Act (NEPA) project flow sheet was to be formulated for the environmental impact statement. Water quality criteria for Florida waters were to be established

Existence of positive solutions for nonlocal second-order boundary value problem with variable parameter in Banach spaces

Directory of Open Access Journals (Sweden)

Zhang Peiguo

2011-01-01

Full Text Available Abstract By obtaining intervals of the parameter λ, this article investigates the existence of a positive solution for a class of nonlinear boundary value problems of second-order differential equations with integral boundary conditions in abstract spaces. The arguments are based upon a specially constructed cone and the fixed point theory in cone for a strict set contraction operator. MSC: 34B15; 34B16.

Survey of Beamed Energy Propulsion Concepts by the MSFC Space Environmental Effects Team

Science.gov (United States)

Gray, P. A.; Nehls, M. K.; Edwards, D. L.; Carruth, M. R., Jr.; Munafo, Paul M. (Technical Monitor)

2002-01-01

This will be a survey paper of work that was performed by the Space Environmental Effects Team at NASA's Marshall Space Flight Center in the area of laser energy propulsion concepts. Two types of laser energy propulsion techniques were investigated. The first was ablative propulsion, which used a pulsed ruby laser impacting on single layer coatings and films. The purpose of this investigation was to determine the laser power density that produced an optimum coupling coefficient for each type of material tested. A commercial off-the-shelf multi-layer film was also investigated for possible applications in ablative micro-thrusters, and its optimum coupling coefficient was determined. The second type of study measured the purely photonic force provided by a 300W CW YAG laser. In initial studies, the photon force resulting from the momentum of incident photons was measured directly using a vacuum compatible microbalance and these results were compared to theory. Follow-on work used the same CW laser to excite a stable optical cavity for the purpose of amplifying the available force from incident photons.

Integrated Logistics Support Analysis of the International Space Station Alpha: An Overview of the Maintenance Time Dependent Parameter Prediction Methods Enhancement

Science.gov (United States)

Sepehry-Fard, F.; Coulthard, Maurice H.

1995-01-01

The objective of this publication is to introduce the enhancement methods for the overall reliability and maintainability methods of assessment on the International Space Station. It is essential that the process to predict the values of the maintenance time dependent variable parameters such as mean time between failure (MTBF) over time do not in themselves generate uncontrolled deviation in the results of the ILS analysis such as life cycle costs, spares calculation, etc. Furthermore, the very acute problems of micrometeorite, Cosmic rays, flares, atomic oxygen, ionization effects, orbital plumes and all the other factors that differentiate maintainable space operations from non-maintainable space operations and/or ground operations must be accounted for. Therefore, these parameters need be subjected to a special and complex process. Since reliability and maintainability strongly depend on the operating conditions that are encountered during the entire life of the International Space Station, it is important that such conditions are accurately identified at the beginning of the logistics support requirements process. Environmental conditions which exert a strong influence on International Space Station will be discussed in this report. Concurrent (combined) space environments may be more detrimental to the reliability and maintainability of the International Space Station than the effects of a single environment. In characterizing the logistics support requirements process, the developed design/test criteria must consider both the single and/or combined environments in anticipation of providing hardware capability to withstand the hazards of the International Space Station profile. The effects of the combined environments (typical) in a matrix relationship on the International Space Station will be shown. The combinations of the environments where the total effect is more damaging than the cumulative effects of the environments acting singly, may include a

THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VIII. PRELIMINARY PUBLIC CATALOG RELEASE

Energy Technology Data Exchange (ETDEWEB)

Soto, M.; Bellini, A.; Anderson, J.; Van der Marel, R. P.; Brown, T. M. [Space Telescope Science Institute, San Martin Drive 3700, Baltimore, MD 21218 (United States); Piotto, G.; Granata, V.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Cool, A. M. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); King, I. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Cassisi, S. [Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); Aparicio, A.; Hidalgo, S., E-mail: mario.soto@uda.cl [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain)

2017-01-01

The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GO-13297) has been specifically designed to complement the existing F606W and F814W observations of the Advanced Camera for Surveys (ACS) Globular Cluster Survey (GO-10775) by observing the most accessible 47 of the previous survey’s 65 clusters in three WFC3/UVIS filters F275W, F336W, and F438W. The new survey also adds super-solar metallicity open cluster NGC 6791 to increase the metallicity diversity. The combined survey provides a homogeneous 5-band data set that can be used to pursue a broad range of scientific investigations. In particular, the chosen UV filters allow the identification of multiple stellar populations by targeting the regions of the spectrum that are sensitive to abundance variations in C, N, and O. In order to provide the community with uniform preliminary catalogs, we have devised an automated procedure that performs high-quality photometry on the new UV observations (along with similar observations of seven other programs in the archive). This procedure finds and measures the potential sources on each individual exposure using library point-spread functions and cross-correlates these observations with the original ACS-Survey catalog. The catalog of 57 clusters we publish here will be useful to identify stars in the different stellar populations, in particular for spectroscopic follow-up. Eventually, we will construct a more sophisticated catalog and artificial-star tests based on an optimal reduction of the UV survey data, but the catalogs presented here give the community the chance to make early use of this HST Treasury survey.

On the Essence of Space

Science.gov (United States)

Kalanov, Temur Z.

2003-04-01

A new theory of space is suggested. It represents the new point of view which has arisen from the critical analysis of the foundations of physics (in particular the theory of relativity and quantum mechanics), mathematics, cosmology and philosophy. The main idea following from the analysis is that the concept of movement represents a key to understanding of the essence of space. The starting-point of the theory is represented by the following philosophical (dialectical materialistic) principles. (a) The principle of the materiality (of the objective reality) of the Nature: the Nature (the Universe) is a system (a set) of material objects (particles, bodies, fields); each object has properties, features, and the properties, the features are inseparable characteristics of material object and belong only to material object. (b) The principle of the existence of material object: an object exists as the objective reality, and movement is a form of existence of object. (c) The principle (definition) of movement of object: the movement is change (i.e. transition of some states into others) in general; the movement determines a direction, and direction characterizes the movement. (d) The principle of existence of time: the time exists as the parameter of the system of reference. These principles lead to the following statements expressing the essence of space. (1) There is no space in general, and there exist space only as a form of existence of the properties and features of the object. It means that the space is a set of the measures of the object (the measure is the philosophical category meaning unity of the qualitative and quantitative determinacy of the object). In other words, the space of the object is a set of the states of the object. (2) The states of the object are manifested only in a system of reference. The main informational property of the unitary system researched physical object + system of reference is that the system of reference determines (measures

Dark energy and neutrino constraints from a future EUCLID-like survey

CERN Document Server

Basse, Tobias; Hamann, Jan; Hannestad, Steen; Wong, Yvonne Y.Y.

2014-01-01

We perform a detailed forecast on how well a Euclid-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We find that the combination of these three probes vastly improves the survey's potential to measure the time evolution of dark energy. In terms of a dark energy figure-of-merit defined as (sigma(w_0) sigma(w_a))^-1, we find a value of 454 for Euclid-like data combined with Planck-like measurements of the cosmic microwave background (CMB) anisotropies in a fiducial LambdaCDM cosmology, a number that is quite conservative compared with existing estimates because of our choice of model parameter space and analysis method, but still represents a factor of 3 to 8 improvement over using either CMB+galaxy clustering+cosmic shear data, or CMB+cluster mass function alone. We consider also the survey's potential to measure dark energy perturbations in models wherein the dark ene...

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

Science.gov (United States)

Plyusnin, V. V.; Reux, C.; Kiptily, V. G.; Pautasso, G.; Decker, J.; Papp, G.; Kallenbach, A.; Weinzettl, V.; Mlynar, J.; Coda, S.; Riccardo, V.; Lomas, P.; Jachmich, S.; Shevelev, A. E.; Alper, B.; Khilkevitch, E.; Martin, Y.; Dux, R.; Fuchs, C.; Duval, B.; Brix, M.; Tardini, G.; Maraschek, M.; Treutterer, W.; Giannone, L.; Mlynek, A.; Ficker, O.; Martin, P.; Gerasimov, S.; Potzel, S.; Paprok, R.; McCarthy, P. J.; Imrisek, M.; Boboc, A.; Lackner, K.; Fernandes, A.; Havlicek, J.; Giacomelli, L.; Vlainic, M.; Nocente, M.; Kruezi, U.; COMPASS Team; TCV Team; ASDEX-Upgrade Team; EUROFusion MST1 Team; contributors, JET

2018-01-01

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70-75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.

3D-HST: A WIDE-FIELD GRISM SPECTROSCOPIC SURVEY WITH THE HUBBLE SPACE TELESCOPE

International Nuclear Information System (INIS)

Brammer, Gabriel B.; Van Dokkum, Pieter G.; Skelton, Rosalind E.; Nelson, Erica; Bezanson, Rachel; Leja, Joel; Lundgren, Britt; Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Labbé, Ivo; Rix, Hans-Walter; Schmidt, Kasper B.; Da Cunha, Elisabete; Kriek, Mariska; Erb, Dawn K.; Fan, Xiaohui; Förster Schreiber, Natascha; Illingworth, Garth D.; Magee, Dan

2012-01-01

We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for a sample of ∼7000 galaxies at 1 2 ) of the CANDELS Treasury survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of ∼5 per resolution element at H 140 ∼ 23.1 and a 5σ emission-line sensitivity of ∼5 × 10 –17 erg s –1 cm –2 for typical objects, improving by a factor of ∼2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1 to 1.6 μm at a spatial resolution of ∼0.''13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary reduction and analysis of the grism observations, including emission-line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of σ(z) = 0.0034(1 + z), or σ(v) ≈ 1000 km s –1 . We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z = 4.7, quiescent galaxies at z ∼ 2, and the most distant T-type brown dwarf star known. The combination of the CANDELS and 3D-HST surveys will provide the definitive imaging and spectroscopic data set for studies of the 1 < z < 3.5 universe until the launch of the James Webb Space Telescope.

Associations among q-space MRI, diffusion-weighted MRI and histopathological parameters in meningiomas

Energy Technology Data Exchange (ETDEWEB)

Fatima, Zareen; Motosugi, Utaroh; Ishigame, Keiichi; Araki, Tsutomu [University of Yamanashi, Department of Radiology, Chuo-shi, Yamanashi (Japan); Waqar, Ahmed Bilal [University of Yamanashi, Department of Molecular Pathology, Interdisciplinary Graduate School of Medicine and Engineering, Chuo-shi, Yamanashi (Japan); Hori, Masaaki [Juntendo University, Department of Radiology, School of Medicine, Tokyo (Japan); Oishi, Naoki; Katoh, Ryohei [University of Yamanashi, Department of Pathology, Chuo-shi, Yamanashi (Japan); Onodera, Toshiyuki; Yagi, Kazuo [Tokyo Metropolitan University, Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo (Japan)

2013-08-15

The purposes of this MR-based study were to calculate q-space imaging (QSI)-derived mean displacement (MDP) in meningiomas, to evaluate the correlation of MDP values with apparent diffusion coefficient (ADC) and to investigate the relationships among these diffusion parameters, tumour cell count (TCC) and MIB-1 labelling index (LI). MRI, including QSI and conventional diffusion-weighted imaging (DWI), was performed in 44 meningioma patients (52 lesions). ADC and MDP maps were acquired from post-processing of the data. Quantitative analyses of these maps were performed by applying regions of interest. Pearson correlation coefficients were calculated for ADC and MDP in all lesions and for ADC and TCC, MDP and TCC, ADC and MIB-1 LI, and MDP and MIB-1 LI in 17 patients who underwent subsequent surgery. ADC and MDP values were found to have a strong correlation: r = 0.78 (P = <0.0001). Both ADC and MDP values had a significant negative association with TCC: r = -0.53 (p = 0.02) and -0.48 (P = 0.04), respectively. MIB-1 LI was not, however, found to have a significant association with these diffusion parameters. In meningiomas, both ADC and MDP may be representative of cell density. (orig.)

Associations among q-space MRI, diffusion-weighted MRI and histopathological parameters in meningiomas

International Nuclear Information System (INIS)

Fatima, Zareen; Motosugi, Utaroh; Ishigame, Keiichi; Araki, Tsutomu; Waqar, Ahmed Bilal; Hori, Masaaki; Oishi, Naoki; Katoh, Ryohei; Onodera, Toshiyuki; Yagi, Kazuo

2013-01-01

The purposes of this MR-based study were to calculate q-space imaging (QSI)-derived mean displacement (MDP) in meningiomas, to evaluate the correlation of MDP values with apparent diffusion coefficient (ADC) and to investigate the relationships among these diffusion parameters, tumour cell count (TCC) and MIB-1 labelling index (LI). MRI, including QSI and conventional diffusion-weighted imaging (DWI), was performed in 44 meningioma patients (52 lesions). ADC and MDP maps were acquired from post-processing of the data. Quantitative analyses of these maps were performed by applying regions of interest. Pearson correlation coefficients were calculated for ADC and MDP in all lesions and for ADC and TCC, MDP and TCC, ADC and MIB-1 LI, and MDP and MIB-1 LI in 17 patients who underwent subsequent surgery. ADC and MDP values were found to have a strong correlation: r = 0.78 (P = <0.0001). Both ADC and MDP values had a significant negative association with TCC: r = -0.53 (p = 0.02) and -0.48 (P = 0.04), respectively. MIB-1 LI was not, however, found to have a significant association with these diffusion parameters. In meningiomas, both ADC and MDP may be representative of cell density. (orig.)

SU-F-T-366: Dosimetric Parameters Enhancement of 120-Leaf Millennium MLC Using EGSnrc and IAEA Phase-Space Data

International Nuclear Information System (INIS)

Haddad, K; Alopoor, H

2016-01-01

Purpose: Recently, the multileaf collimators (MLC) have become an important part of any LINAC collimation systems because they reduce the treatment planning time and improves the conformity. Important factors that affects the MLCs collimation performance are leaves material composition and their thickness. In this study, we investigate the main dosimetric parameters of 120-leaf Millennium MLC including dose in the buildup point, physical penumbra as well as average and end leaf leakages. Effects of the leaves geometry and density on these parameters are evaluated Methods: From EGSnrc Monte Carlo code, BEAMnrc and DOSXYZnrc modules are used to evaluate the dosimetric parameters of a water phantom exposed to a Varian xi for 100cm SSD. Using IAEA phasespace data just above MLC (Z=46cm) and BEAMnrc, for the modified 120-leaf Millennium MLC a new phase space data at Z=52cm is produces. The MLC is modified both in leaf thickness and material composition. EGSgui code generates 521ICRU library for tungsten alloys. DOSXYZnrc with the new phase space evaluates the dose distribution in a water phantom of 60×60×20 cm3 with voxel size of 4×4×2 mm3. Using DOSXYZnrc dose distributions for open beam and closed beam as well as the leakages definition, end leakage, average leakage and physical penumbra are evaluated. Results: A new MLC with improved dosimetric parameters is proposed. The physical penumbra for proposed MLC is 4.7mm compared to 5.16 mm for Millennium. Average leakage in our design is reduced to 1.16% compared to 1.73% for Millennium, the end leaf leakage suggested design is also reduced to 4.86% compared to 7.26% of Millennium. Conclusion: The results show that the proposed MLC with enhanced dosimetric parameters could improve the conformity of treatment planning.

SU-F-T-366: Dosimetric Parameters Enhancement of 120-Leaf Millennium MLC Using EGSnrc and IAEA Phase-Space Data

Energy Technology Data Exchange (ETDEWEB)

Haddad, K; Alopoor, H [Shiraz University, Shiraz, I.R. Iran (Iran, Islamic Republic of)

2016-06-15

Purpose: Recently, the multileaf collimators (MLC) have become an important part of any LINAC collimation systems because they reduce the treatment planning time and improves the conformity. Important factors that affects the MLCs collimation performance are leaves material composition and their thickness. In this study, we investigate the main dosimetric parameters of 120-leaf Millennium MLC including dose in the buildup point, physical penumbra as well as average and end leaf leakages. Effects of the leaves geometry and density on these parameters are evaluated Methods: From EGSnrc Monte Carlo code, BEAMnrc and DOSXYZnrc modules are used to evaluate the dosimetric parameters of a water phantom exposed to a Varian xi for 100cm SSD. Using IAEA phasespace data just above MLC (Z=46cm) and BEAMnrc, for the modified 120-leaf Millennium MLC a new phase space data at Z=52cm is produces. The MLC is modified both in leaf thickness and material composition. EGSgui code generates 521ICRU library for tungsten alloys. DOSXYZnrc with the new phase space evaluates the dose distribution in a water phantom of 60×60×20 cm3 with voxel size of 4×4×2 mm3. Using DOSXYZnrc dose distributions for open beam and closed beam as well as the leakages definition, end leakage, average leakage and physical penumbra are evaluated. Results: A new MLC with improved dosimetric parameters is proposed. The physical penumbra for proposed MLC is 4.7mm compared to 5.16 mm for Millennium. Average leakage in our design is reduced to 1.16% compared to 1.73% for Millennium, the end leaf leakage suggested design is also reduced to 4.86% compared to 7.26% of Millennium. Conclusion: The results show that the proposed MLC with enhanced dosimetric parameters could improve the conformity of treatment planning.

A hybrid method of estimating pulsating flow parameters in the space-time domain

Science.gov (United States)

Pałczyński, Tomasz

2017-05-01

This paper presents a method for estimating pulsating flow parameters in partially open pipes, such as pipelines, internal combustion engine inlets, exhaust pipes and piston compressors. The procedure is based on the method of characteristics, and employs a combination of measurements and simulations. An experimental test rig is described, which enables pressure, temperature and mass flow rate to be measured within a defined cross section. The second part of the paper discusses the main assumptions of a simulation algorithm elaborated in the Matlab/Simulink environment. The simulation results are shown as 3D plots in the space-time domain, and compared with proposed models of phenomena relating to wave propagation, boundary conditions, acoustics and fluid mechanics. The simulation results are finally compared with acoustic phenomena, with an emphasis on the identification of resonant frequencies.

Concepts of space the history of theories of space in physics

CERN Document Server

Jammer, Max

1993-01-01

Historical surveys consider Judeo-Christian notions of space, Newtonian absolute space, perceptions from 18th century to the present, more. Numerous quotations and references. "Admirably compact and swiftly paced style." - Philosophy of Science.

Accounting for baryonic effects in cosmic shear tomography: Determining a minimal set of nuisance parameters using PCA

Energy Technology Data Exchange (ETDEWEB)

Eifler, Tim; Krause, Elisabeth; Dodelson, Scott; Zentner, Andrew; Hearin, Andrew; Gnedin, Nickolay

2014-05-28

Systematic uncertainties that have been subdominant in past large-scale structure (LSS) surveys are likely to exceed statistical uncertainties of current and future LSS data sets, potentially limiting the extraction of cosmological information. Here we present a general framework (PCA marginalization) to consistently incorporate systematic effects into a likelihood analysis. This technique naturally accounts for degeneracies between nuisance parameters and can substantially reduce the dimension of the parameter space that needs to be sampled. As a practical application, we apply PCA marginalization to account for baryonic physics as an uncertainty in cosmic shear tomography. Specifically, we use CosmoLike to run simulated likelihood analyses on three independent sets of numerical simulations, each covering a wide range of baryonic scenarios differing in cooling, star formation, and feedback mechanisms. We simulate a Stage III (Dark Energy Survey) and Stage IV (Large Synoptic Survey Telescope/Euclid) survey and find a substantial bias in cosmological constraints if baryonic physics is not accounted for. We then show that PCA marginalization (employing at most 3 to 4 nuisance parameters) removes this bias. Our study demonstrates that it is possible to obtain robust, precise constraints on the dark energy equation of state even in the presence of large levels of systematic uncertainty in astrophysical processes. We conclude that the PCA marginalization technique is a powerful, general tool for addressing many of the challenges facing the precision cosmology program.

Testing general relativity at cosmological scales: Implementation and parameter correlations

International Nuclear Information System (INIS)

Dossett, Jason N.; Ishak, Mustapha; Moldenhauer, Jacob

2011-01-01

The testing of general relativity at cosmological scales has become a possible and timely endeavor that is not only motivated by the pressing question of cosmic acceleration but also by the proposals of some extensions to general relativity that would manifest themselves at large scales of distance. We analyze here correlations between modified gravity growth parameters and some core cosmological parameters using the latest cosmological data sets including the refined Cosmic Evolution Survey 3D weak lensing. We provide the parametrized modified growth equations and their evolution. We implement known functional and binning approaches, and propose a new hybrid approach to evolve the modified gravity parameters in redshift (time) and scale. The hybrid parametrization combines a binned redshift dependence and a smooth evolution in scale avoiding a jump in the matter power spectrum. The formalism developed to test the consistency of current and future data with general relativity is implemented in a package that we make publicly available and call ISiTGR (Integrated Software in Testing General Relativity), an integrated set of modified modules for the publicly available packages CosmoMC and CAMB, including a modified version of the integrated Sachs-Wolfe-galaxy cross correlation module of Ho et al. and a new weak-lensing likelihood module for the refined Hubble Space Telescope Cosmic Evolution Survey weak gravitational lensing tomography data. We obtain parameter constraints and correlation coefficients finding that modified gravity parameters are significantly correlated with σ 8 and mildly correlated with Ω m , for all evolution methods. The degeneracies between σ 8 and modified gravity parameters are found to be substantial for the functional form and also for some specific bins in the hybrid and binned methods indicating that these degeneracies will need to be taken into consideration when using future high precision data.

Impact of Anthropogenic Factor on Urboecological Space Development

Directory of Open Access Journals (Sweden)

Kuprina Tamara

2016-01-01

Full Text Available The article discusses the issues of the impact of the anthropogenic factor on urboecological space development. The issues are considered taking into account retrospective theoretical data to show the process of Anthropoecology development as a new branch of sociological science. At present the noosphere acquires features of anthropoecosystems having a number of parameters from the endogenous and exogenous point of view. Anthropoecology has special socio-cultural significance as considers the interaction of all actors of international space. There introduced the new branch Ecopsycology as the outer world is the reflection of the inner human world. There is a definition of the sustainability of ecological system. In the practical part of the article there is an example of academic mobility as the basis of the human potential with possible transfer into the human capital supporting by survey data. In conclusion there are recommendations on management and adaptation of the anthropogenic factor (a kind of biogenesis in modern urboecological space.

Parameter analysis calculation on characteristics of portable FAST reactor

International Nuclear Information System (INIS)

Otsubo, Akira; Kowata, Yasuki

1998-06-01

In this report, we performed a parameter survey analysis by using the analysis program code STEDFAST (Space, TErrestrial and Deep sea FAST reactor-gas turbine system). Concerning the deep sea fast reactor-gas turbine system, calculations with many variable parameters were performed on the base case of a NaK cooled reactor of 40 kWe. We aimed at total equipment weight and surface area necessary to remove heat from the system as important values of the characteristics of the system. Electric generation power and the material of a pressure hull were specially influential for the weight. The electric generation power, reactor outlet/inlet temperatures, a natural convection heat transfer coefficient of sea water were specially influential for the area. Concerning the space reactor-gas turbine system, the calculations with the variable parameters of compressor inlet temperature, reactor outlet/inlet temperatures and turbine inlet pressure were performed on the base case of a Na cooled reactor of 40 kWe. The first and the second variable parameters were influential for the total equipment weight of the important characteristic of the system. Concerning the terrestrial fast reactor-gas turbine system, the calculations with the variable parameters of heat transferred pipe number in a heat exchanger to produce hot water of 100degC for cogeneration, compressor stage number and the kind of primary coolant material were performed on the base case of a Pb cooled reactor of 100 MWt. In the comparison of calculational results for Pb and Na of primary coolant material, the primary coolant weight flow rate was naturally large for the former case compared with for the latter case because density is very different between them. (J.P.N.)

Effects of simulated space environmental parameters on six commercially available composite materials

International Nuclear Information System (INIS)

Funk, J.G.; Sykes, G.F. Jr.

1989-04-01

The effects of simulated space environmental parameters on microdamage induced by the environment in a series of commercially available graphite-fiber-reinforced composite materials were determined. Composites with both thermoset and thermoplastic resin systems were studied. Low-Earth-Orbit (LEO) exposures were simulated by thermal cycling; geosynchronous-orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. The thermal cycling temperature range was -250 F to either 200 F or 150 F. The upper limits of the thermal cycles were different to ensure that an individual composite material was not cycled above its glass transition temperature. Material response was characterized through assessment of the induced microcracking and its influence on mechanical property changes at both room temperature and -250 F. Microdamage was induced in both thermoset and thermoplastic advanced composite materials exposed to the simulated LEO environment. However, a 350 F cure single-phase toughened epoxy composite was not damaged during exposure to the LEO environment. The simuated GEO environment produced microdamage in all materials tested

Massive data compression for parameter-dependent covariance matrices

Science.gov (United States)

Heavens, Alan F.; Sellentin, Elena; de Mijolla, Damien; Vianello, Alvise

2017-12-01

We show how the massive data compression algorithm MOPED can be used to reduce, by orders of magnitude, the number of simulated data sets which are required to estimate the covariance matrix required for the analysis of Gaussian-distributed data. This is relevant when the covariance matrix cannot be calculated directly. The compression is especially valuable when the covariance matrix varies with the model parameters. In this case, it may be prohibitively expensive to run enough simulations to estimate the full covariance matrix throughout the parameter space. This compression may be particularly valuable for the next generation of weak lensing surveys, such as proposed for Euclid and Large Synoptic Survey Telescope, for which the number of summary data (such as band power or shear correlation estimates) is very large, ∼104, due to the large number of tomographic redshift bins which the data will be divided into. In the pessimistic case where the covariance matrix is estimated separately for all points in an Monte Carlo Markov Chain analysis, this may require an unfeasible 109 simulations. We show here that MOPED can reduce this number by a factor of 1000, or a factor of ∼106 if some regularity in the covariance matrix is assumed, reducing the number of simulations required to a manageable 103, making an otherwise intractable analysis feasible.

Concept for an International Standard related to Space Weather Effects on Space Systems

Science.gov (United States)

Tobiska, W. Kent; Tomky, Alyssa

There is great interest in developing an international standard related to space weather in order to specify the tools and parameters needed for space systems operations. In particular, a standard is important for satellite operators who may not be familiar with space weather. In addition, there are others who participate in space systems operations that would also benefit from such a document. For example, the developers of software systems that provide LEO satellite orbit determination, radio communication availability for scintillation events (GEO-to-ground L and UHF bands), GPS uncertainties, and the radiation environment from ground-to-space for commercial space tourism. These groups require recent historical data, current epoch specification, and forecast of space weather events into their automated or manual systems. Other examples are national government agencies that rely on space weather data provided by their organizations such as those represented in the International Space Environment Service (ISES) group of 14 national agencies. Designers, manufacturers, and launchers of space systems require real-time, operational space weather parameters that can be measured, monitored, or built into automated systems. Thus, a broad scope for the document will provide a useful international standard product to a variety of engineering and science domains. The structure of the document should contain a well-defined scope, consensus space weather terms and definitions, and internationally accepted descriptions of the main elements of space weather, its sources, and its effects upon space systems. Appendices will be useful for describing expanded material such as guidelines on how to use the standard, how to obtain specific space weather parameters, and short but detailed descriptions such as when best to use some parameters and not others; appendices provide a path for easily updating the standard since the domain of space weather is rapidly changing with new advances

Isometries on Banach spaces function spaces

CERN Document Server

Fleming, Richard J

2002-01-01

Fundamental to the study of any mathematical structure is an understanding of its symmetries. In the class of Banach spaces, this leads naturally to a study of isometries-the linear transformations that preserve distances. In his foundational treatise, Banach showed that every linear isometry on the space of continuous functions on a compact metric space must transform a continuous function x into a continuous function y satisfying y(t) = h(t)x(p(t)), where p is a homeomorphism and |h| is identically one.Isometries on Banach Spaces: Function Spaces is the first of two planned volumes that survey investigations of Banach-space isometries. This volume emphasizes the characterization of isometries and focuses on establishing the type of explicit, canonical form given above in a variety of settings. After an introductory discussion of isometries in general, four chapters are devoted to describing the isometries on classical function spaces. The final chapter explores isometries on Banach algebras.This treatment p...

Surgeon Reported Outcome Measure for Spine Trauma an International Expert Survey Identifying Parameters Relevant for The Outcome of Subaxial Cervical Spine Injuries

NARCIS (Netherlands)

Sadiqi, Said; Verlaan, Jorrit Jan; Lehr, A. M.; Dvorak, Marcel F.; Kandziora, Frank; Rajasekaran, S.; Schnake, Klaus J.; Vaccaro, Alexander R.; Oner, F. C.

2016-01-01

STUDY DESIGN.: International web-based survey OBJECTIVE.: To identify clinical and radiological parameters that spine surgeons consider most relevant when evaluating clinical and functional outcomes of subaxial cervical spine trauma patients. SUMMARY OF BACKGROUND DATA.: While an outcome instrument

Triple Junction InGaP/GaAs/Ge Solar Cell Optimization: The Design Parameters for a 36.2% Efficient Space Cell Using Silvaco ATLAS Modeling & Simulation

OpenAIRE

Tsutagawa, Michael H.; Michael, Sherif

2009-01-01

This paper presents the design parameters for a triple junction InGaP/GaAs/Ge space solar cell with a simulated maximum efficiency of 36.28% using Silvaco ATLAS Virtual Wafer Fabrication tool. Design parameters include the layer material, doping concentration, and thicknesses.

Equilibrium phase-space distributions and space charge limits in linacs

International Nuclear Information System (INIS)

Lysenko, W.P.

1977-10-01

Limits on beam current and emittance in proton and heavy ion linear accelerators resulting from space charge forces are calculated. The method involves determining equilibrium distributions in phase space using a continuous focusing, no acceleration, model in two degrees of freedom using the coordinates r and z. A nonlinear Poisson equation must be solved numerically. This procedure is a matching between the longitudinal and transverse directions to minimize the effect of longitudinal-transverse coupling which is believed to be the main problem in emittance growth due to space charge in linacs. Limits on the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator performance are calculated as an example. The beam physics is described by a few space charge parameters so that accelerators with different physical parameters can be compared in a natural way. The main result of this parameter study is that the requirement of a high-intensity beam is best fulfilled with a low-frequency accelerator whereas the requirement of a high-brightness beam is best fulfilled with a high-frequency accelerator

Buncher system parameter optimization

International Nuclear Information System (INIS)

Wadlinger, E.A.

1981-01-01

A least-squares algorithm is presented to calculate the RF amplitudes and cavity spacings for a series of buncher cavities each resonating at a frequency that is a multiple of a fundamental frequency of interest. The longitudinal phase-space distribution, obtained by particle tracing through the bunching system, is compared to a desired distribution function of energy and phase. The buncher cavity parameters are adjusted to minimize the difference between these two distributions. Examples are given for zero space charge. The manner in which the method can be extended to include space charge using the 3-D space-charge calculation procedure is indicated

Design Considerations: Falcon M Dwarf Habitable Exoplanet Survey

Science.gov (United States)

Polsgrove, Daniel; Novotny, Steven; Della-Rose, Devin J.; Chun, Francis; Tippets, Roger; O'Shea, Patrick; Miller, Matthew

2016-01-01

The Falcon Telescope Network (FTN) is an assemblage of twelve automated 20-inch telescopes positioned around the globe, controlled from the Cadet Space Operations Center (CSOC) at the US Air Force Academy (USAFA) in Colorado Springs, Colorado. Five of the 12 sites are currently installed, with full operational capability expected by the end of 2016. Though optimized for studying near-earth objects to accomplish its primary mission of Space Situational Awareness (SSA), the Falcon telescopes are in many ways similar to those used by ongoing and planned exoplanet transit surveys targeting individual M dwarf stars (e.g., MEarth, APACHE, SPECULOOS). The network's worldwide geographic distribution provides additional potential advantages. We have performed analytical and empirical studies exploring the viability of employing the FTN for a future survey of nearby late-type M dwarfs tailored to detect transits of 1-2REarth exoplanets in habitable-zone orbits . We present empirical results on photometric precision derived from data collected with multiple Falcon telescopes on a set of nearby (survey design parameters is also described, including an analysis of site-specific weather data, anticipated telescope time allocation and the percentage of nearby M dwarfs with sufficient check stars within the Falcons' 11' x 11' field-of-view required to perform effective differential photometry. The results of this ongoing effort will inform the likelihood of discovering one (or more) habitable-zone exoplanets given current occurrence rate estimates over a nominal five-year campaign, and will dictate specific survey design features in preparation for initiating project execution when the FTN begins full-scale automated operations.

A new Bayesian recursive technique for parameter estimation

Science.gov (United States)

Kaheil, Yasir H.; Gill, M. Kashif; McKee, Mac; Bastidas, Luis

2006-08-01

The performance of any model depends on how well its associated parameters are estimated. In the current application, a localized Bayesian recursive estimation (LOBARE) approach is devised for parameter estimation. The LOBARE methodology is an extension of the Bayesian recursive estimation (BARE) method. It is applied in this paper on two different types of models: an artificial intelligence (AI) model in the form of a support vector machine (SVM) application for forecasting soil moisture and a conceptual rainfall-runoff (CRR) model represented by the Sacramento soil moisture accounting (SAC-SMA) model. Support vector machines, based on statistical learning theory (SLT), represent the modeling task as a quadratic optimization problem and have already been used in various applications in hydrology. They require estimation of three parameters. SAC-SMA is a very well known model that estimates runoff. It has a 13-dimensional parameter space. In the LOBARE approach presented here, Bayesian inference is used in an iterative fashion to estimate the parameter space that will most likely enclose a best parameter set. This is done by narrowing the sampling space through updating the "parent" bounds based on their fitness. These bounds are actually the parameter sets that were selected by BARE runs on subspaces of the initial parameter space. The new approach results in faster convergence toward the optimal parameter set using minimum training/calibration data and fewer sets of parameter values. The efficacy of the localized methodology is also compared with the previously used BARE algorithm.

Online State Space Model Parameter Estimation in Synchronous Machines

Directory of Open Access Journals (Sweden)

Z. Gallehdari

2014-06-01

The suggested approach is evaluated for a sample synchronous machine model. Estimated parameters are tested for different inputs at different operating conditions. The effect of noise is also considered in this study. Simulation results show that the proposed approach provides good accuracy for parameter estimation.

Organic chemistry in space

Science.gov (United States)

Johnson, R. D.

1977-01-01

Organic cosmochemistry, organic materials in space exploration, and biochemistry of man in space are briefly surveyed. A model of Jupiter's atmosphere is considered, and the search for organic molecules in the solar system and in interstellar space is discussed. Materials and analytical techniques relevant to space exploration are indicated, and the blood and urine analyses performed on Skylab are described.

DRAGON solutions to the 3D transport benchmark over a range in parameter space

International Nuclear Information System (INIS)

Martin, Nicolas; Hebert, Alain; Marleau, Guy

2010-01-01

DRAGON solutions to the 'NEA suite of benchmarks for 3D transport methods and codes over a range in parameter space' are discussed in this paper. A description of the benchmark is first provided, followed by a detailed review of the different computational models used in the lattice code DRAGON. Two numerical methods were selected for generating the required quantities for the 729 configurations of this benchmark. First, S N calculations were performed using fully symmetric angular quadratures and high-order diamond differencing for spatial discretization. To compare S N results with those of another deterministic method, the method of characteristics (MoC) was also considered for this benchmark. Comparisons between reference solutions, S N and MoC results illustrate the advantages and drawbacks of each methods for this 3-D transport problem.

A statistical model for estimation of fish density including correlation in size, space, time and between species from research survey data

DEFF Research Database (Denmark)

Nielsen, J. Rasmus; Kristensen, Kasper; Lewy, Peter

2014-01-01

Trawl survey data with high spatial and seasonal coverage were analysed using a variant of the Log Gaussian Cox Process (LGCP) statistical model to estimate unbiased relative fish densities. The model estimates correlations between observations according to time, space, and fish size and includes...

Aeromagnetic survey in Eurajoensalmi, Olkiluoto 2008

International Nuclear Information System (INIS)

Levaeniemi, H.

2008-08-01

This report describes the survey operation, survey and processing methods and the deliverables of an aerogeophysical survey in Olkiluoto area in April 2008. The survey was conducted by Geological Survey of Finland (GTK). The survey aircraft was a twin-engine Twin Otter operated by Finnish Aviation Academy (SIO) and owned by Natural Environment Research Council / British Geological Survey (NERC / BGS), with whom GTK has established a joint venture called Joint Airborne-geoscience Capability (JAC). The survey was conducted in April 2008 during six days. The survey consists of six separate survey flights, one of which was a magnetic calibration flight. The survey was based in Pori airport. Survey line spacing was 50 meters and nominal survey altitude was 30 meters. Measurements were completed in April 2008, and data processing and reporting was done in June 2008. Two cesium magnetometers installed onboard the aircraft (at the left wingtip and in a nose cone) were measuring the magnetic total field intensity during the survey flights. An automatic compensation unit corrected the aircraft attitude errors in the magnetic data in real time. In addition to magnetic measurement, auxiliary parameters such as flight altitude and aircraft attitude were also recorded simultaneously. Reference ground base station was used for recording the temporal variations in the magnetic field and also reference data for post-positioning of coordinate information. In the post-processing phase, heading correction, base station correction and microlevelling procedures were applied to the magnetic data. The data was exported to numeric XYZ files and interpolated into grid data file. A noteworthy local detail present in the survey and in the processing was the massive power line. For safety reasons, flight altitude had to be increased and survey lines had to be cut short in the vicinity of the powerline. However, due to reasonable planning of the survey area boundaries, this caused no great

An integral-field spectroscopic strong lens survey

International Nuclear Information System (INIS)

Bolton, Adam S; Burles, Scott

2007-01-01

We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

GRID-BASED EXPLORATION OF COSMOLOGICAL PARAMETER SPACE WITH SNAKE

International Nuclear Information System (INIS)

Mikkelsen, K.; Næss, S. K.; Eriksen, H. K.

2013-01-01

We present a fully parallelized grid-based parameter estimation algorithm for investigating multidimensional likelihoods called Snake, and apply it to cosmological parameter estimation. The basic idea is to map out the likelihood grid-cell by grid-cell according to decreasing likelihood, and stop when a certain threshold has been reached. This approach improves vastly on the 'curse of dimensionality' problem plaguing standard grid-based parameter estimation simply by disregarding grid cells with negligible likelihood. The main advantages of this method compared to standard Metropolis-Hastings Markov Chain Monte Carlo methods include (1) trivial extraction of arbitrary conditional distributions; (2) direct access to Bayesian evidences; (3) better sampling of the tails of the distribution; and (4) nearly perfect parallelization scaling. The main disadvantage is, as in the case of brute-force grid-based evaluation, a dependency on the number of parameters, N par . One of the main goals of the present paper is to determine how large N par can be, while still maintaining reasonable computational efficiency; we find that N par = 12 is well within the capabilities of the method. The performance of the code is tested by comparing cosmological parameters estimated using Snake and the WMAP-7 data with those obtained using CosmoMC, the current standard code in the field. We find fully consistent results, with similar computational expenses, but shorter wall time due to the perfect parallelization scheme

Radiation shielding aspects for long manned mission to space - Criteria, survey study and preliminary model

International Nuclear Information System (INIS)

Sztejnberg, M.; Xiao, S.; Satvat, N.; Limon, F.; Hopkins, J.; Jevremovic, T.; T. Jevremovic)

2006-01-01

The prospect of manned space missions out side Earth's or bit is limited by the travel time and shielding against cosmic radiation. The chemical rockets currently used in the space program have no hope of propelling a manned vehicle to a far away location such as Mars due to the enormous mass of fuel that would be required. The specific energy available from nuclear fuel is a factor of 106 higher than chemical fuel; it is there fore obvious that nuclear power production in space is a must. On the other hand, recent considerations to send a man to the Moon for a long stay would require a stable, secured, and safe source of energy (there is hardly anything beyond nuclear power that would provide a useful and reliably safe sustainable supply of energy). National Aeronautics and Space Administration (NASA) anticipates that the mass of a shielding material required for long travel to Mars is the next major design driver. In 2006 NASA identified a need to assess and evaluate potential gaps in existing knowledge and understanding of the level and types of radiation critical to astronauts' health during the long travel to Mars and to start a comprehensive study related to the shielding design of a spacecraft finding the conditions for the mitigation of radiation components contributing to the doses beyond accepted limits. In order to reduce the overall space craft mass, NASA is looking for the novel, multi-purpose and multi-functional materials that will provide effective shielding of the crew and electronics on board. The Laboratory for Neutronics and Geometry Computation in the School of Nuclear Engineering at Purdue University led by Prof. Tatjana Jevremovic began in 2004 the analytical evaluations of different lightweight materials. The preliminary results of the design survey study are presented in this paper. (author)

Radiation shielding aspects for long manned mission to space: Criteria, survey study, and preliminary model

Directory of Open Access Journals (Sweden)

Sztejnberg Manuel

2006-01-01

Full Text Available The prospect of manned space missions outside Earth's orbit is limited by the travel time and shielding against cosmic radiation. The chemical rockets currently used in the space program have no hope of propelling a manned vehicle to a far away location such as Mars due to the enormous mass of fuel that would be required. The specific energy available from nuclear fuel is a factor of 106 higher than chemical fuel; it is therefore obvious that nuclear power production in space is a must. On the other hand, recent considerations to send a man to the Moon for a long stay would require a stable, secured and safe source of energy (there is hardly anything beyond nuclear power that would provide a useful and reliably safe sustainable supply of energy. National Aeronautics and Space Administration (NASA anticipates that the mass of a shielding material required for long travel to Mars is the next major design driver. In 2006 NASA identified a need to assess and evaluate potential gaps in existing knowledge and understanding of the level and types of radiation critical to astronauts' health during the long travel to Mars and to start a comprehensive study related to the shielding design of a spacecraft finding the conditions for the mitigation of radiation components contributing to the doses beyond accepted limits. In order to reduce the overall space craft mass, NASA is looking for the novel, multi-purpose and multi-functional materials that will provide effective shielding of the crew and electronics on board. The Laboratory for Neutronics and Geometry Computation in the School of Nuclear Engineering at Purdue University led by Prof. Tatjana Jevremović began in 2004 the analytical evaluations of different lightweight materials. The preliminary results of the design survey study are presented in this paper.

WFIRST: Science from Deep Field Surveys

Science.gov (United States)

Koekemoer, Anton; Foley, Ryan; WFIRST Deep Field Working Group

2018-01-01

WFIRST will enable deep field imaging across much larger areas than those previously obtained with Hubble, opening up completely new areas of parameter space for extragalactic deep fields including cosmology, supernova and galaxy evolution science. The instantaneous field of view of the Wide Field Instrument (WFI) is about 0.3 square degrees, which would for example yield an Ultra Deep Field (UDF) reaching similar depths at visible and near-infrared wavelengths to that obtained with Hubble, over an area about 100-200 times larger, for a comparable investment in time. Moreover, wider fields on scales of 10-20 square degrees could achieve depths comparable to large HST surveys at medium depths such as GOODS and CANDELS, and would enable multi-epoch supernova science that could be matched in area to LSST Deep Drilling fields or other large survey areas. Such fields may benefit from being placed on locations in the sky that have ancillary multi-band imaging or spectroscopy from other facilities, from the ground or in space. The WFIRST Deep Fields Working Group has been examining the science considerations for various types of deep fields that may be obtained with WFIRST, and present here a summary of the various properties of different locations in the sky that may be considered for future deep fields with WFIRST.

SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20

Energy Technology Data Exchange (ETDEWEB)

Yanny, Brian; /Fermilab; Rockosi, Constance; /UC, Santa Cruz; Newberg, Heidi Jo; /Rensselaer Poly.; Knapp, Gillian R.; /Princeton U.; Adelman-McCarthy, Jennifer K.; /Fermilab; Alcorn, Bonnie; /Fermilab; Allam, Sahar S.; /Fermilab; Prieto, Carlos Allende; /Texas U. /University Coll. London; An, Deokkeun; /Ohio State U.; Anderson, Kurt S.J.; /Apache Point Observ. /New Mexico State U.; Anderson, Scott; /Washington U., Seattle

2009-02-01

The Sloan Extension for Galactic Understanding and Exploration (SEGUE) Survey obtained {approx}240,000 moderate-resolution (R {approx} 1800) spectra from 3900 {angstrom} to 9000 {angstrom} of fainter Milky Way stars (14.0 < g < 20.3) of a wide variety of spectral types, both main-sequence and evolved objects, with the goal of studying the kinematics and populations of our Galaxy and its halo. The spectra are clustered in 212 regions spaced over three quarters of the sky. Radial velocity accuracies for stars are {sigma}(RV) {approx} 4 km s{sup -1} at g < 18, degrading to {sigma}(RV) {approx} 15 km s{sup -1} at g {approx} 20. For stars with signal-to-noise ratio >10 per resolution element, stellar atmospheric parameters are estimated, including metallicity, surface gravity, and effective temperature. SEGUE obtained 3500 deg{sup 2} of additional ugriz imaging (primarily at low Galactic latitudes) providing precise multicolor photometry ({sigma}(g, r, i) {approx} 2%), ({sigma}(u, z) {approx} 3%) and astrometry ({approx}0.1) for spectroscopic target selection. The stellar spectra, imaging data, and derived parameter catalogs for this survey are publicly available as part of Sloan Digital Sky Survey Data Release 7.

GRID-BASED EXPLORATION OF COSMOLOGICAL PARAMETER SPACE WITH SNAKE

Energy Technology Data Exchange (ETDEWEB)

Mikkelsen, K.; Næss, S. K.; Eriksen, H. K., E-mail: kristin.mikkelsen@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway)

2013-11-10

We present a fully parallelized grid-based parameter estimation algorithm for investigating multidimensional likelihoods called Snake, and apply it to cosmological parameter estimation. The basic idea is to map out the likelihood grid-cell by grid-cell according to decreasing likelihood, and stop when a certain threshold has been reached. This approach improves vastly on the 'curse of dimensionality' problem plaguing standard grid-based parameter estimation simply by disregarding grid cells with negligible likelihood. The main advantages of this method compared to standard Metropolis-Hastings Markov Chain Monte Carlo methods include (1) trivial extraction of arbitrary conditional distributions; (2) direct access to Bayesian evidences; (3) better sampling of the tails of the distribution; and (4) nearly perfect parallelization scaling. The main disadvantage is, as in the case of brute-force grid-based evaluation, a dependency on the number of parameters, N{sub par}. One of the main goals of the present paper is to determine how large N{sub par} can be, while still maintaining reasonable computational efficiency; we find that N{sub par} = 12 is well within the capabilities of the method. The performance of the code is tested by comparing cosmological parameters estimated using Snake and the WMAP-7 data with those obtained using CosmoMC, the current standard code in the field. We find fully consistent results, with similar computational expenses, but shorter wall time due to the perfect parallelization scheme.

Maximal compression of the redshift-space galaxy power spectrum and bispectrum

Science.gov (United States)

Gualdi, Davide; Manera, Marc; Joachimi, Benjamin; Lahav, Ofer

2018-05-01

We explore two methods of compressing the redshift-space galaxy power spectrum and bispectrum with respect to a chosen set of cosmological parameters. Both methods involve reducing the dimension of the original data vector (e.g. 1000 elements) to the number of cosmological parameters considered (e.g. seven ) using the Karhunen-Loève algorithm. In the first case, we run MCMC sampling on the compressed data vector in order to recover the 1D and 2D posterior distributions. The second option, approximately 2000 times faster, works by orthogonalizing the parameter space through diagonalization of the Fisher information matrix before the compression, obtaining the posterior distributions without the need of MCMC sampling. Using these methods for future spectroscopic redshift surveys like DESI, Euclid, and PFS would drastically reduce the number of simulations needed to compute accurate covariance matrices with minimal loss of constraining power. We consider a redshift bin of a DESI-like experiment. Using the power spectrum combined with the bispectrum as a data vector, both compression methods on average recover the 68 {per cent} credible regions to within 0.7 {per cent} and 2 {per cent} of those resulting from standard MCMC sampling, respectively. These confidence intervals are also smaller than the ones obtained using only the power spectrum by 81 per cent, 80 per cent, and 82 per cent respectively, for the bias parameter b1, the growth rate f, and the scalar amplitude parameter As.

Finding viable models in SUSY parameter spaces with signal specific discovery potential

Science.gov (United States)

Burgess, Thomas; Lindroos, Jan Øye; Lipniacka, Anna; Sandaker, Heidi

2013-08-01

Recent results from ATLAS giving a Higgs mass of 125.5 GeV, further constrain already highly constrained supersymmetric models such as pMSSM or CMSSM/mSUGRA. As a consequence, finding potentially discoverable and non-excluded regions of model parameter space is becoming increasingly difficult. Several groups have invested large effort in studying the consequences of Higgs mass bounds, upper limits on rare B-meson decays, and limits on relic dark matter density on constrained models, aiming at predicting superpartner masses, and establishing likelihood of SUSY models compared to that of the Standard Model vis-á-vis experimental data. In this paper a framework for efficient search for discoverable, non-excluded regions of different SUSY spaces giving specific experimental signature of interest is presented. The method employs an improved Markov Chain Monte Carlo (MCMC) scheme exploiting an iteratively updated likelihood function to guide search for viable models. Existing experimental and theoretical bounds as well as the LHC discovery potential are taken into account. This includes recent bounds on relic dark matter density, the Higgs sector and rare B-mesons decays. A clustering algorithm is applied to classify selected models according to expected phenomenology enabling automated choice of experimental benchmarks and regions to be used for optimizing searches. The aim is to provide experimentalist with a viable tool helping to target experimental signatures to search for, once a class of models of interest is established. As an example a search for viable CMSSM models with τ-lepton signatures observable with the 2012 LHC data set is presented. In the search 105209 unique models were probed. From these, ten reference benchmark points covering different ranges of phenomenological observables at the LHC were selected.

Subchannel and bundle friction factors and flow split parameters for laminar transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays

International Nuclear Information System (INIS)

Hawley, J.T.; Chiu, C.; Todreas, N.E.; Rohsenow, W.M.

1980-01-01

Correlations are presented for subchannel and bundle friction factors and flowsplit parameters for laminar, transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays. These results are obtained from pressure drop models of flow in individual subchannels. For turbulent flow, an existing pressure drop model for flow in edge subchannels is extended, and the resulting edge subchannel friction factor is identified. Using the expressions for flowsplit parameters and the equal pressure drops assumption, the interior subchannel and bundle friction factors are obtained. For laminar flow, models are developed for pressure drops of individual subchannels. From these models, expressions for the subchannel friction factors are identified and expressions for the flowsplit parameters are derived

Subchannel and bundle friction factors and flowsplit parameters for laminar, transition, and turbulent longitudinal flows in wire-wrap spaced hexagonal arrays. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Hawley, J.T.; Chiu, C.; Rohsenow, W.M.; Todreas, N.E.

1980-08-01

Correlations are presented for subchannel and bundle friction factors and flowsplit parameters for laminar, transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays. These results are obtained from pressure drop models of flow in individual subchannels. For turbulent flow, an existing pressure drop model for flow in edge subchannels is extended, and the resulting edge subchannel friction factor is identified. Using the expressions for flowsplit parameters and the equal pressured drop assumption, the interior subchannel and bundle friction factors are obtained. For laminar flow, models are developed for pressure drops of individual subchannels. From these models, expressions for the subchannel friction factors are identified and expressions for the flowsplit parameters are derived.

Geoid of Nepal from airborne gravity survey

DEFF Research Database (Denmark)

Forsberg, René; Olesen, Arne Vestergaard; Einarsson, Indriði

2011-01-01

An airborne gravity survey of Nepal was carried out December 2010 in a cooperation between DTU-Space, Nepal Survey Department, and NGA, USA. The entire country was flown with survey lines spaced 6 nm with a King Air aircraft, with a varying flight altitude from 4 to 10 km. The survey operations...... as well as recent GPS-heights of Mt. Everest. The new airborne data also provide an independent validation of GOCE gravity field results at the local ~100 km resolution scale....

Optimization of operating parameters of ground source heat pump system for space heating and cooling by Taguchi method and utility concept

International Nuclear Information System (INIS)

Sivasakthivel, T.; Murugesan, K.; Thomas, H.R.

2014-01-01

Highlights: • Ground Source Heat Pump (GSHP) technology is suitable for both heating and cooling. • Important parameters that affect the GSHP performance has been listed. • Parameters of GSHP system has been optimized for heating and cooling mode. • Taguchi technique and utility concept are developed for GSHP optimization. - Abstract: Use of ground source energy for space heating applications through Ground Source Heat pump (GSHP) has been established as an efficient thermodynamic process. The electricity input to the GSHP can be reduced by increasing the COP of the system. However, the COP of a GSHP system will be different for heating and cooling mode operations. Hence in order to reduce the electricity input to the GSHP, an optimum value of COP has to be determined when GSHP is operated in both heating and cooling modes. In the present research, a methodology is proposed to optimize the operating parameters of a GSHP system which will operate on both heating and cooling modes. Condenser inlet temperature, condenser outlet temperature, dryness fraction at evaporator inlet and evaporator outlet temperature are considered as the influencing parameters of the heat pump. Optimization of these parameters for only heating or only cooling mode operation is achieved by employing Taguchi method for three level variations of the above parameters using an L 9 (3 4 ) orthogonal array. Higher the better concept has been used to get a higher COP. A computer program in FORTAN has been developed to carry out the computations and the results have been analyzed for the optimum conditions using Signal-to-Noise (SN) ratio and Analysis Of Variance (ANOVA) method. Based on this analysis, the maximum COP for only heating and only cooling operation are obtained as 4.25 and 3.32 respectively. By making use of the utility concept both the higher values of COP obtained for heating and cooling modes are optimized to get a single optimum COP for heating and cooling modes. A single

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: constraining modified gravity

Science.gov (United States)

Mueller, Eva-Maria; Percival, Will; Linder, Eric; Alam, Shadab; Zhao, Gong-Bo; Sánchez, Ariel G.; Beutler, Florian; Brinkmann, Jon

2018-04-01

We use baryon acoustic oscillation and redshift space distortion from the completed Baryon Oscillation Spectroscopic Survey, corresponding to Data Release 12 of the Sloan Digital Sky Survey, combined sample analysis in combination with cosmic microwave background, supernova, and redshift space distortion measurements from additional spectroscopic surveys to test deviations from general relativity. We present constraints on several phenomenological models of modified gravity: First, we parametrize the growth of structure using the growth index γ, finding γ = 0.566 ± 0.058 (68 per cent C.L.). Secondly, we modify the relation of the two Newtonian potentials by introducing two additional parameters, GM and GL. In this approach, GM refers to modifications of the growth of structure whereas GL to modification of the lensing potential. We consider a power law to model the redshift dependence of GM and GL as well as binning in redshift space, introducing four additional degrees of freedom, GM(z 0.5), GL(z 0.5). At 68 per cent C.L., we measure GM = 0.980 ± 0.096 and GL = 1.082 ± 0.060 for a linear model, GM = 1.01 ± 0.36 and GL = 1.31 ± 0.19 for a cubic model as well as GM(z 0.5) = 0.986 ± 0.022, GL(z 0.5) = 1.037 ± 0.029. Thirdly, we investigate general scalar tensor theories of gravity, finding the model to be mostly unconstrained by current data. Assuming a one-parameter f(R) model, we can constrain B0 < 7.7 × 10-5 (95 per cent C.L). For all models we considered, we find good agreement with general relativity.

Theoretical Models of Optical Transients. I. A Broad Exploration of the Duration-Luminosity Phase Space

Science.gov (United States)

Villar, V. Ashley; Berger, Edo; Metzger, Brian D.; Guillochon, James

2017-11-01

The duration-luminosity phase space (DLPS) of optical transients is used, mostly heuristically, to compare various classes of transient events, to explore the origin of new transients, and to influence optical survey observing strategies. For example, several observational searches have been guided by intriguing voids and gaps in this phase space. However, we should ask, do we expect to find transients in these voids given our understanding of the various heating sources operating in astrophysical transients? In this work, we explore a broad range of theoretical models and empirical relations to generate optical light curves and to populate the DLPS. We explore transients powered by adiabatic expansion, radioactive decay, magnetar spin-down, and circumstellar interaction. For each heating source, we provide a concise summary of the basic physical processes, a physically motivated choice of model parameter ranges, an overall summary of the resulting light curves and their occupied range in the DLPS, and how the various model input parameters affect the light curves. We specifically explore the key voids discussed in the literature: the intermediate-luminosity gap between classical novae and supernovae, and short-duration transients (≲ 10 days). We find that few physical models lead to transients that occupy these voids. Moreover, we find that only relativistic expansion can produce fast and luminous transients, while for all other heating sources events with durations ≲ 10 days are dim ({M}{{R}}≳ -15 mag). Finally, we explore the detection potential of optical surveys (e.g., Large Synoptic Survey Telescope) in the DLPS and quantify the notion that short-duration and dim transients are exponentially more difficult to discover in untargeted surveys.

Efficient Mosaicking of Spitzer Space Telescope Images

Science.gov (United States)

Jacob, Joseph; Makovoz, David; Eisenhardt, Peter

2007-01-01

A parallel version of the MOPEX software, which generates mosaics of infrared astronomical images acquired by the Spitzer Space Telescope, extends the capabilities of the prior serial version. In the parallel version, both the input image space and the output mosaic space are divided among the available parallel processors. This is the only software that performs the point-source detection and the rejection of spurious imaging effects of cosmic rays required by Spitzer scientists. This software includes components that implement outlier-detection algorithms that can be fine-tuned for a particular set of image data by use of a number of adjustable parameters. This software has been used to construct a mosaic of the Spitzer Infrared Array Camera Shallow Survey, which comprises more than 17,000 exposures in four wavelength bands from 3.6 to 8 m and spans a solid angle of about 9 square degrees. When this software was executed on 32 nodes of the 1,024-processor Cosmos cluster computer at NASA s Jet Propulsion Laboratory, a speedup of 8.3 was achieved over the serial version of MOPEX. The performance is expected to improve dramatically once a true parallel file system is installed on Cosmos.

Effect of 90-day space flight (MDS-ISS) on immunological parameters in mice: lymphocyte distribution and function

Science.gov (United States)

Roberts, Arthur; Lhuillier, Andrew; Liu, Yi; Ruggiu, Alessandra; Shi, Yufang

Elucidation of the effects of space flight on the immune system of astronauts and other animal species is important for the survival and success of manned space flight, especially long-term missions. Space flight exposes astronauts to microgravity, galactic cosmic radiation (GCR), and various psycho-social stressors. Blood samples from astronauts returning from space flight have shown changes in the numbers and types of circulating leukocytes. Similarly, normal lym-phocyte homeostasis has been shown to be severely affected in mice using ground-based models of microgravity and GCR exposure, as demonstrated by profound effects on several immuno-logical parameters examined by other investigators and ourselves. In particular, lymphocyte numbers are significantly reduced and subpopulation distribution is altered in the spleen, thy-mus, and peripheral blood following hindlimb unloading (HU) in mice. Lymphocyte depletion was found to be mediated through corticosteroid-induced apoptosis, although the molecular mechanism of apoptosis induction is still under investigation. The proliferative capacity of TCR-stimulated lymphocytes was also inhibited after HU. We have similarly shown that mice exposed to high-energy 56Fe ion radiation have decreased lymphocyte numbers and perturba-tions in proportions of various subpopulations, including CD4+ and CD8+ T cells, and B cells in the spleen, and maturation stages of immature T cells in the thymus. To compare these ground-based results to the effects of actual space-flight, fresh spleen and thymus samples were recently obtained from normal and transgenic mice immediately after 90 d. space-flight in the MDS, and identically-housed ground control mice. Total leukocyte numbers in each organ were enumerated, and subpopulation distribution was examined by flow cytometric analysis of CD3, CD4, CD8, CD19, CD25, DX-5, and CD11b. Splenic T cells were stimulated with anti-CD3 and assessed for proliferation after 2-4 d., and production of

A Survey of the Homotopy Properties of Inclusion of Certain Types of Configuration Spaces into the Cartesian Product

Institute of Scientific and Technical Information of China (English)

Daciberg Lima GON(C)ALVES; John GUASCHI

2017-01-01

Let X be a topological space.In this survey the authors consider severaltypes of configuration spaces,namely,the classical (usual) configuration spaces Fn(X)and Dn(X),the orbit configuration spaces FGn(X) and FGn(X)/Sn with respect to a freeaction of a group G on X,and the graph configuration spaces FΓn(X) and FΓn(X)/H,where F is a graph and H is a suitable subgroup of the symmetric group Sn.The orderedconfiguration spaces Fn (X),FGn (X),FΓn(X) are all subsets of the n-fold Cartesian productnП1 X of X with itself,and satisfy FGn(X) (C) Fn(X) (C) Frn(X) (C) nП1 X.If A denotes one of these configuration spaces,the authors analyse the difference between A and nП1 X from a topological and homotopical point of view.The principal results known in the literature concern the usual configuration spaces.The authors are particularly interested in the homomorphism on the level of the homotopy groups of the spaces induced by the inclusion (ι):A → nП1 X,the homotopy type of the homotopy fibre I(ι) of the map (ι) via certain constructions on various spaces that depend on X,and the long exact sequence in homotopy of the fibration involving I(ι) and arising from the inclusion (ι).In this respect,if X is either a surface without boundary,in particular if X is the 2-sphere or the real projective plane,or a space whose universal covering is contractible,or an orbit space Sk/G of the k-dimensional sphere by a free action of a Lie group G,the authors present recent results obtained by themselves for the first case,and in collaboration with Golasi(n)ski for the second and third cases.The authors also briefly indicate some older results relative to the homotopy of these spaces that are related to the problems of interest.In order to motivate various questions,for the remaining types of configuration spaces,a few of their basic properties are described and proved.A list of open questions and problems is given at the end of the paper.

Study on TVD parameters sensitivity of a crankshaft using multiple scale and state space method considering quadratic and cubic non-linearities

Directory of Open Access Journals (Sweden)

R. Talebitooti

Full Text Available In this paper the effect of quadratic and cubic non-linearities of the system consisting of the crankshaft and torsional vibration damper (TVD is taken into account. TVD consists of non-linear elastomer material used for controlling the torsional vibration of crankshaft. The method of multiple scales is used to solve the governing equations of the system. Meanwhile, the frequency response of the system for both harmonic and sub-harmonic resonances is extracted. In addition, the effects of detuning parameters and other dimensionless parameters for a case of harmonic resonance are investigated. Moreover, the external forces including both inertia and gas forces are simultaneously applied into the model. Finally, in order to study the effectiveness of the parameters, the dimensionless governing equations of the system are solved, considering the state space method. Then, the effects of the torsional damper as well as all corresponding parameters of the system are discussed.

Comparison of Satellite Surveying to Traditional Surveying Methods for the Resources Industry

Science.gov (United States)

Osborne, B. P.; Osborne, V. J.; Kruger, M. L.

Modern ground-based survey methods involve detailed survey, which provides three-space co-ordinates for surveyed points, to a high level of accuracy. The instruments are operated by surveyors, who process the raw results to create survey location maps for the subject of the survey. Such surveys are conducted for a location or region and referenced to the earth global co- ordinate system with global positioning system (GPS) positioning. Due to this referencing the survey is only as accurate as the GPS reference system. Satellite survey remote sensing utilise satellite imagery which have been processed using commercial geographic information system software. Three-space co-ordinate maps are generated, with an accuracy determined by the datum position accuracy and optical resolution of the satellite platform.This paper presents a case study, which compares topographic surveying undertaken by traditional survey methods with satellite surveying, for the same location. The purpose of this study is to assess the viability of satellite remote sensing for surveying in the resources industry. The case study involves a topographic survey of a dune field for a prospective mining project area in Pakistan. This site has been surveyed using modern surveying techniques and the results are compared to a satellite survey performed on the same area.Analysis of the results from traditional survey and from the satellite survey involved a comparison of the derived spatial co- ordinates from each method. In addition, comparisons have been made of costs and turnaround time for both methods.The results of this application of remote sensing is of particular interest for survey in areas with remote and extreme environments, weather extremes, political unrest, poor travel links, which are commonly associated with mining projects. Such areas frequently suffer language barriers, poor onsite technical support and resources.

Parametric cost estimation for space science missions

Science.gov (United States)

Lillie, Charles F.; Thompson, Bruce E.

2008-07-01

Cost estimation for space science missions is critically important in budgeting for successful missions. The process requires consideration of a number of parameters, where many of the values are only known to a limited accuracy. The results of cost estimation are not perfect, but must be calculated and compared with the estimates that the government uses for budgeting purposes. Uncertainties in the input parameters result from evolving requirements for missions that are typically the "first of a kind" with "state-of-the-art" instruments and new spacecraft and payload technologies that make it difficult to base estimates on the cost histories of previous missions. Even the cost of heritage avionics is uncertain due to parts obsolescence and the resulting redesign work. Through experience and use of industry best practices developed in participation with the Aerospace Industries Association (AIA), Northrop Grumman has developed a parametric modeling approach that can provide a reasonably accurate cost range and most probable cost for future space missions. During the initial mission phases, the approach uses mass- and powerbased cost estimating relationships (CER)'s developed with historical data from previous missions. In later mission phases, when the mission requirements are better defined, these estimates are updated with vendor's bids and "bottoms- up", "grass-roots" material and labor cost estimates based on detailed schedules and assigned tasks. In this paper we describe how we develop our CER's for parametric cost estimation and how they can be applied to estimate the costs for future space science missions like those presented to the Astronomy & Astrophysics Decadal Survey Study Committees.

Fungi in space--literature survey on fungi used for space research.

Science.gov (United States)

Kern, V D; Hock, B

1993-09-01

A complete review of the scientific literature on experiments involving fungi in space is presented. This review begins with balloon experiments around 1935 which carried fungal spores, rocket experiments in the 1950's and 60's, satellite and moon expeditions, long-time orbit experiments and Spacelab missions in the 1980's and 90's. All these missions were aimed at examining the influence of cosmic radiation and weightlessness on genetic, physiological, and morphogenetic processes. During the 2nd German Spacelab mission (D-2, April/May 1993), the experiment FUNGI provided the facilities to cultivate higher basidiomycetes over a period of 10 d in orbit, document gravimorphogenesis and chemically fix fruiting bodies under weightlessness for subsequent ultrastructural analysis. This review shows the necessity of space travel for research on the graviperception of higher fungi and demonstrates the novelty of the experiment FUNGI performed within the framework of the D-2 mission.

THE BOSS EMISSION-LINE LENS SURVEY (BELLS). I. A LARGE SPECTROSCOPICALLY SELECTED SAMPLE OF LENS GALAXIES AT REDSHIFT {approx}0.5

Energy Technology Data Exchange (ETDEWEB)

Brownstein, Joel R.; Bolton, Adam S.; Pandey, Parul [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard College Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Seitz, Stella [University Observatory Munich, Scheinstrasse 1, 81679 Muenchen (Germany); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Wood-Vasey, W. Michael [Pittsburgh Center for Particle Physics, Astrophysics, and Cosmology (PITT-PACC), Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, PA 16802 (United States); Weaver, Benjamin A. [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

2012-01-01

We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 {approx}< z {approx}< 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution.

Health sciences libraries building survey, 1999-2009.

Science.gov (United States)

Ludwig, Logan

2010-04-01

A survey was conducted of health sciences libraries to obtain information about newer buildings, additions, remodeling, and renovations. An online survey was developed, and announcements of survey availability posted to three major email discussion lists: Medical Library Association (MLA), Association of Academic Health Sciences Libraries (AAHSL), and MEDLIB-L. Previous discussions of library building projects on email discussion lists, a literature review, personal communications, and the author's consulting experiences identified additional projects. Seventy-eight health sciences library building projects at seventy-three institutions are reported. Twenty-two are newer facilities built within the last ten years; two are space expansions; forty-five are renovation projects; and nine are combinations of new and renovated space. Six institutions report multiple or ongoing renovation projects during the last ten years. The survey results confirm a continuing migration from print-based to digitally based collections and reveal trends in library space design. Some health sciences libraries report loss of space as they move toward creating space for "community" building. Libraries are becoming more proactive in using or retooling space for concentration, collaboration, contemplation, communication, and socialization. All are moving toward a clearer operational vision of the library as the institution's information nexus and not merely as a physical location with print collections.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 3: Literature surveys and technical reports

Science.gov (United States)

1992-01-01

The technical effort and computer code developed during the first year are summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis.

Neutrino oscillation parameter sampling with MonteCUBES

Science.gov (United States)

Blennow, Mattias; Fernandez-Martinez, Enrique

2010-01-01

We present MonteCUBES ("Monte Carlo Utility Based Experiment Simulator"), a software package designed to sample the neutrino oscillation parameter space through Markov Chain Monte Carlo algorithms. MonteCUBES makes use of the GLoBES software so that the existing experiment definitions for GLoBES, describing long baseline and reactor experiments, can be used with MonteCUBES. MonteCUBES consists of two main parts: The first is a C library, written as a plug-in for GLoBES, implementing the Markov Chain Monte Carlo algorithm to sample the parameter space. The second part is a user-friendly graphical Matlab interface to easily read, analyze, plot and export the results of the parameter space sampling. Program summaryProgram title: MonteCUBES (Monte Carlo Utility Based Experiment Simulator) Catalogue identifier: AEFJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 69 634 No. of bytes in distributed program, including test data, etc.: 3 980 776 Distribution format: tar.gz Programming language: C Computer: MonteCUBES builds and installs on 32 bit and 64 bit Linux systems where GLoBES is installed Operating system: 32 bit and 64 bit Linux RAM: Typically a few MBs Classification: 11.1 External routines: GLoBES [1,2] and routines/libraries used by GLoBES Subprograms used:Cat Id ADZI_v1_0, Title GLoBES, Reference CPC 177 (2007) 439 Nature of problem: Since neutrino masses do not appear in the standard model of particle physics, many models of neutrino masses also induce other types of new physics, which could affect the outcome of neutrino oscillation experiments. In general, these new physics imply high-dimensional parameter spaces that are difficult to explore using classical methods such as multi-dimensional projections and minimizations, such as those

Weakly infinite-dimensional spaces

International Nuclear Information System (INIS)

Fedorchuk, Vitalii V

2007-01-01

In this survey article two new classes of spaces are considered: m-C-spaces and w-m-C-spaces, m=2,3,...,∞. They are intermediate between the class of weakly infinite-dimensional spaces in the Alexandroff sense and the class of C-spaces. The classes of 2-C-spaces and w-2-C-spaces coincide with the class of weakly infinite-dimensional spaces, while the compact ∞-C-spaces are exactly the C-compact spaces of Haver. The main results of the theory of weakly infinite-dimensional spaces, including classification via transfinite Lebesgue dimensions and Luzin-Sierpinsky indices, extend to these new classes of spaces. Weak m-C-spaces are characterised by means of essential maps to Henderson's m-compacta. The existence of hereditarily m-strongly infinite-dimensional spaces is proved.

Near-Earth Object Survey Simulation Software

Science.gov (United States)

Naidu, Shantanu P.; Chesley, Steven R.; Farnocchia, Davide

2017-10-01

There is a significant interest in Near-Earth objects (NEOs) because they pose an impact threat to Earth, offer valuable scientific information, and are potential targets for robotic and human exploration. The number of NEO discoveries has been rising rapidly over the last two decades with over 1800 being discovered last year, making the total number of known NEOs >16000. Pan-STARRS and the Catalina Sky Survey are currently the most prolific NEO surveys, having discovered >1600 NEOs between them in 2016. As next generation surveys such as Large Synoptic Survey Telescope (LSST) and the proposed Near-Earth Object Camera (NEOCam) become operational in the next decade, the discovery rate is expected to increase tremendously. Coordination between various survey telescopes will be necessary in order to optimize NEO discoveries and create a unified global NEO discovery network. We are collaborating on a community-based, open-source software project to simulate asteroid surveys to facilitate such coordination and develop strategies for improving discovery efficiency. Our effort so far has focused on development of a fast and efficient tool capable of accepting user-defined asteroid population models and telescope parameters such as a list of pointing angles and camera field-of-view, and generating an output list of detectable asteroids. The software takes advantage of the widely used and tested SPICE library and architecture developed by NASA’s Navigation and Ancillary Information Facility (Acton, 1996) for saving and retrieving asteroid trajectories and camera pointing. Orbit propagation is done using OpenOrb (Granvik et al. 2009) but future versions will allow the user to plug in a propagator of their choice. The software allows the simulation of both ground-based and space-based surveys. Performance is being tested using the Grav et al. (2011) asteroid population model and the LSST simulated survey “enigma_1189”.

Origins Space Telescope: 3D infrared surveys of star formation and black hole growth in galaxies over cosmic time

Science.gov (United States)

Pope, Alexandra; Armus, Lee; bradford, charles; Origins Space Telescope STDT

2018-01-01

In the coming decade, new telescope facilities and surveys aim to provide a 3D map of the unobscured Universe over cosmic time. However, much of galaxy formation and evolution occurs behind dust, and is only observable through infrared observations. Previous extragalactic infrared surveys were fundamentally limited to a 2D mapping of the most extreme populations of galaxies due to spatial resolution and sensitivity. The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies sponsored by NASA to provide input to the 2020 Astronomy and Astrophysics Decadal survey. OST is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum, which will achieve spectral line sensitivities up to 1000 times deeper than previous infrared facilities. With powerful instruments such as the Medium Resolution Survey Spectrometer (MRSS), capable of simultaneous imaging and spectroscopy, the extragalactic infrared sky can finally be surveyed in 3D. In addition to spectroscopic redshifts, the rich suite of lines in the infrared provides unique diagnostics of the ongoing star formation (both obscured and unobscured) and the central supermassive black hole growth. In this poster, we present a simulated extragalactic survey with OST/MRSS which will detect millions of galaxies down to well below the knee of the infrared luminosity function. We demonstrate how this survey can map the coeval star formation and black hole growth in galaxies over cosmic time.

Galaxy bispectrum, primordial non-Gaussianity and redshift space distortions

Energy Technology Data Exchange (ETDEWEB)

Tellarini, Matteo; Ross, Ashley J.; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom); Tasinato, Gianmassimo, E-mail: matteo.tellarini@port.ac.uk, E-mail: ross.1333@osu.edu, E-mail: g.tasinato@swansea.ac.uk, E-mail: david.wands@port.ac.uk [Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom)

2016-06-01

Measurements of the non-Gaussianity of the primordial density field have the power to considerably improve our understanding of the physics of inflation. Indeed, if we can increase the precision of current measurements by an order of magnitude, a null-detection would rule out many classes of scenarios for generating primordial fluctuations. Large-scale galaxy redshift surveys represent experiments that hold the promise to realise this goal. Thus, we model the galaxy bispectrum and forecast the accuracy with which it will probe the parameter f {sub NL}, which represents the degree of primordial local-type non Gaussianity. Specifically, we address the problem of modelling redshift space distortions (RSD) in the tree-level galaxy bispectrum including f {sub NL}. We find novel contributions associated with RSD, with the characteristic large scale amplification induced by local-type non-Gaussianity. These RSD effects must be properly accounted for in order to obtain un-biased measurements of f {sub NL} from the galaxy bispectrum. We propose an analytic template for the monopole which can be used to fit against data on large scales, extending models used in the recent measurements. Finally, we perform idealised forecasts on σ {sub f} {sub N{sub L}}—the accuracy of the determination of local non-linear parameter f {sub NL}—from measurements of the galaxy bispectrum. Our findings suggest that current surveys can in principle provide f {sub NL} constraints competitive with Planck , and future surveys could improve them further.

Galaxy bispectrum, primordial non-Gaussianity and redshift space distortions

International Nuclear Information System (INIS)

Tellarini, Matteo; Ross, Ashley J.; Wands, David; Tasinato, Gianmassimo

2016-01-01

Measurements of the non-Gaussianity of the primordial density field have the power to considerably improve our understanding of the physics of inflation. Indeed, if we can increase the precision of current measurements by an order of magnitude, a null-detection would rule out many classes of scenarios for generating primordial fluctuations. Large-scale galaxy redshift surveys represent experiments that hold the promise to realise this goal. Thus, we model the galaxy bispectrum and forecast the accuracy with which it will probe the parameter f NL , which represents the degree of primordial local-type non Gaussianity. Specifically, we address the problem of modelling redshift space distortions (RSD) in the tree-level galaxy bispectrum including f NL . We find novel contributions associated with RSD, with the characteristic large scale amplification induced by local-type non-Gaussianity. These RSD effects must be properly accounted for in order to obtain un-biased measurements of f NL from the galaxy bispectrum. We propose an analytic template for the monopole which can be used to fit against data on large scales, extending models used in the recent measurements. Finally, we perform idealised forecasts on σ f NL —the accuracy of the determination of local non-linear parameter f NL —from measurements of the galaxy bispectrum. Our findings suggest that current surveys can in principle provide f NL constraints competitive with Planck , and future surveys could improve them further.

Improved Space Object Orbit Determination Using CMOS Detectors

Science.gov (United States)

Schildknecht, T.; Peltonen, J.; Sännti, T.; Silha, J.; Flohrer, T.

2014-09-01

CMOS-sensors, or in general Active Pixel Sensors (APS), are rapidly replacing CCDs in the consumer camera market. Due to significant technological advances during the past years these devices start to compete with CCDs also for demanding scientific imaging applications, in particular in the astronomy community. CMOS detectors offer a series of inherent advantages compared to CCDs, due to the structure of their basic pixel cells, which each contains their own amplifier and readout electronics. The most prominent advantages for space object observations are the extremely fast and flexible readout capabilities, feasibility for electronic shuttering and precise epoch registration, and the potential to perform image processing operations on-chip and in real-time. The major challenges and design drivers for ground-based and space-based optical observation strategies have been analyzed. CMOS detector characteristics were critically evaluated and compared with the established CCD technology, especially with respect to the above mentioned observations. Similarly, the desirable on-chip processing functionalities which would further enhance the object detection and image segmentation were identified. Finally, we simulated several observation scenarios for ground- and space-based sensor by assuming different observation and sensor properties. We will introduce the analyzed end-to-end simulations of the ground- and space-based strategies in order to investigate the orbit determination accuracy and its sensitivity which may result from different values for the frame-rate, pixel scale, astrometric and epoch registration accuracies. Two cases were simulated, a survey using a ground-based sensor to observe objects in LEO for surveillance applications, and a statistical survey with a space-based sensor orbiting in LEO observing small-size debris in LEO. The ground-based LEO survey uses a dynamical fence close to the Earth shadow a few hours after sunset. For the space-based scenario

Precision Parameter Estimation and Machine Learning

Science.gov (United States)

Wandelt, Benjamin D.

2008-12-01

I discuss the strategy of ``Acceleration by Parallel Precomputation and Learning'' (AP-PLe) that can vastly accelerate parameter estimation in high-dimensional parameter spaces and costly likelihood functions, using trivially parallel computing to speed up sequential exploration of parameter space. This strategy combines the power of distributed computing with machine learning and Markov-Chain Monte Carlo techniques efficiently to explore a likelihood function, posterior distribution or χ2-surface. This strategy is particularly successful in cases where computing the likelihood is costly and the number of parameters is moderate or large. We apply this technique to two central problems in cosmology: the solution of the cosmological parameter estimation problem with sufficient accuracy for the Planck data using PICo; and the detailed calculation of cosmological helium and hydrogen recombination with RICO. Since the APPLe approach is designed to be able to use massively parallel resources to speed up problems that are inherently serial, we can bring the power of distributed computing to bear on parameter estimation problems. We have demonstrated this with the CosmologyatHome project.

Probability Distribution for Flowing Interval Spacing

International Nuclear Information System (INIS)

Kuzio, S.

2001-01-01

The purpose of this analysis is to develop a probability distribution for flowing interval spacing. A flowing interval is defined as a fractured zone that transmits flow in the Saturated Zone (SZ), as identified through borehole flow meter surveys (Figure 1). This analysis uses the term ''flowing interval spacing'' as opposed to fractured spacing, which is typically used in the literature. The term fracture spacing was not used in this analysis because the data used identify a zone (or a flowing interval) that contains fluid-conducting fractures but does not distinguish how many or which fractures comprise the flowing interval. The flowing interval spacing is measured between the midpoints of each flowing interval. Fracture spacing within the SZ is defined as the spacing between fractures, with no regard to which fractures are carrying flow. The Development Plan associated with this analysis is entitled, ''Probability Distribution for Flowing Interval Spacing'', (CRWMS M and O 2000a). The parameter from this analysis may be used in the TSPA SR/LA Saturated Zone Flow and Transport Work Direction and Planning Documents: (1) ''Abstraction of Matrix Diffusion for SZ Flow and Transport Analyses'' (CRWMS M and O 1999a) and (2) ''Incorporation of Heterogeneity in SZ Flow and Transport Analyses'', (CRWMS M and O 1999b). A limitation of this analysis is that the probability distribution of flowing interval spacing may underestimate the effect of incorporating matrix diffusion processes in the SZ transport model because of the possible overestimation of the flowing interval spacing. Larger flowing interval spacing results in a decrease in the matrix diffusion processes. This analysis may overestimate the flowing interval spacing because the number of fractures that contribute to a flowing interval cannot be determined from the data. Because each flowing interval probably has more than one fracture contributing to a flowing interval, the true flowing interval spacing could be

Real-Time Parameter Identification

Data.gov (United States)

National Aeronautics and Space Administration — Armstrong researchers have implemented in the control room a technique for estimating in real time the aerodynamic parameters that describe the stability and control...

Aerogeophysical survey in Olkiluoto 2009

International Nuclear Information System (INIS)

Kurimo, M.

2009-08-01

This report describes the survey operation, survey and processing methods and the deliverables of an aerogeophysical survey in Olkiluoto area in May 2009. The survey was conducted by Geological Survey of Finland (GTK). The survey aircraft was a twin-engine Twin Otter operated by Finnish Aviation Academy (SIO) and owned by Natural Environment Research Council / British Geological Survey (NERC / BGS), with whom GTK has established a joint venture called Joint Airborne-geoscience Capability (JAC). The survey was conducted in May 2009 between May 5th and May 18th. The survey consists of ten separate survey flights and two magnetic calibration flights. The survey was based in Pori airport. Survey line spacing was 50 meters and nominal survey altitude was 30 meters. Measurements were completed in May 2009, and data processing and reporting was done in June 2009. Two cesium magnetometers installed onboard the aircraft (at the left wingtip and in a nose cone) were measuring the magnetic total field intensity during the survey flights. An automatic compensation unit corrected the aircraft attitude errors in the magnetic data in real time. The four-frequency electromagnetic (EM) unit included four transmitter coils with amplifiers in right wingtip and four receiver coils in left wingtip. Frequencies were 900 Hz, 3 kHz, 14 kHz and 24.5 kHz. The gamma spectrometer with two crystal packages (total volume 42 litres) measured the 256 channel energy spectra. In addition, auxiliary parameters such as flight altitude and aircraft attitude were also recorded simultaneously. Reference ground base station was used for recording the temporal variations in the magnetic field and also reference data for post-positioning of coordinate information. In the post-processing phase, heading correction, base station correction and microlevelling procedures were applied to the magnetic data. The EM data and radiometric data were corrected with calibration coefficients and levelled. The data was

Effect of the grain sizes on the photovoltaic parameters of CdTe solar cells prepared by close space sublimation method

International Nuclear Information System (INIS)

Potlog, T.

2007-01-01

Thin Film CdS/CdTe solar cells were fabricated by Close Space Sublimation at the substrate temperature ranging from 300 degrees ± 5 degrees to 340 degrees ± degrees. The best photovoltaic parameters were achieved at substrate temperature 320 degrees and source temperature 610 degrees. The open circuit voltage and current density changes significantly with the substrate temperature and depends on the dimension of the grain sizes. Grain size is an efficiency limiting parameter for CdTe layers with large grains. The open circuit voltage and current density are the best for the cells having dimension of grains between 1.0 μm and ∼ 5.0 μm. CdS/CdTe solar cells with an efficiency of ∼ 10% were obtained. (author)

Next generation redshift surveys and the origin of cosmic acceleration

International Nuclear Information System (INIS)

Acquaviva, Viviana; Hajian, Amir; Spergel, David N.; Das, Sudeep

2008-01-01

Cosmologists are exploring two possible sets of explanations for the remarkable observation of cosmic acceleration: dark energy fills space or general relativity fails on cosmological scales. We define a null test parameter ε(k,a)≡Ω m -γ dlnD/dlna-1, where a is the scale factor, D is the growth rate of structure, Ω m (a) is the matter density parameter, and γ is a simple function of redshift. We show that it can be expressed entirely in terms of the bias factor, b(a), measured from cross correlations with cosmic microwave background (CMB) lensing, and the amplitude of redshift-space distortions, β(k,a). Measurements of the CMB power spectrum determine Ω m0 H 0 2 . If dark energy within general relativity is the solution to the cosmic acceleration problem, then the logarithmic growth rate of structure dlnD/dlna=Ω m γ . Thus, ε(k,a)=0 on linear scales to better than 1%. We show that in the class of modified gravity models known as f(R), the growth rate has a different dependence on scale and redshift. By combining measurements of the amplitude of β and of the bias, b, redshift surveys will be able to determine the logarithmic growth rate as a function of scale and redshift. We estimate the predicted sensitivity of the proposed SDSS III (BOSS) survey and the proposed ADEPT mission and find that they will test structure growth in general relativity to the percent level.

GESE: A Small UV Space Telescope to Conduct a Large Spectroscopic Survey of Z-1 Galaxies

Science.gov (United States)

Heap, Sara R.; Gong, Qian; Hull, Tony; Kruk, Jeffrey; Purves, Lloyd

2013-01-01

One of the key goals of NASA's astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a space mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at a redshift, z is approximately 1 (look-back time of approximately 8 billion years). GESE is a 1.5-meter space telescope with an ultraviolet (UV) multi-object slit spectrograph that can obtain spectra of hundreds of galaxies per exposure. The spectrograph covers the spectral range, 0.2-0.4 micrometers at a spectral resolving power, R approximately 500. This observed spectral range corresponds to 0.1-0.2 micrometers as emitted by a galaxy at a redshift, z=1. The mission concept takes advantage of two new technological advances: (1) light-weighted, wide-field telescope mirrors, and (2) the Next- Generation MicroShutter Array (NG-MSA) to be used as a slit generator in the multi-object slit spectrograph.

METHOD OF GROUP OBJECTS FORMING FOR SPACE-BASED REMOTE SENSING OF THE EARTH

Directory of Open Access Journals (Sweden)

A. N. Grigoriev

2015-07-01

Full Text Available Subject of Research. Research findings of the specific application of space-based optical-electronic and radar means for the Earth remote sensing are considered. The subject matter of the study is the current planning of objects survey on the underlying surface in order to increase the effectiveness of sensing system due to the rational use of its resources. Method. New concept of a group object, stochastic swath and stochastic length of the route is introduced. The overview of models for single, group objects and their parameters is given. The criterion for the existence of the group object based on two single objects is formulated. The method for group objects formation while current survey planning has been developed and its description is presented. The method comprises several processing stages for data about objects with the calculation of new parameters, the stochastic characteristics of space means and validates the spatial size of the object value of the stochastic swath and stochastic length of the route. The strict mathematical description of techniques for model creation of a group object based on data about a single object and onboard special complex facilities in difficult conditions of registration of spatial data is given. Main Results. The developed method is implemented on the basis of modern geographic information system in the form of a software tool layout with advanced tools of processing and analysis of spatial data in vector format. Experimental studies of the forming method for the group of objects were carried out on a different real object environment using the parameters of modern national systems of the Earth remote sensing detailed observation Canopus-B and Resurs-P. Practical Relevance. The proposed models and method are focused on practical implementation using vector spatial data models and modern geoinformation technologies. Practical value lies in the reduction in the amount of consumable resources by means of

Interpolation of final geometry and result fields in process parameter space

NARCIS (Netherlands)

Misiun, Grzegorz Stefan; Wang, Chao; Geijselaers, Hubertus J.M.; van den Boogaard, Antonius H.; Saanouni, K.

2016-01-01

Different routes to produce a product in a bulk forming process can be described by a limited set of process parameters. The parameters determine the final geometry as well as the distribution of state variables in the final shape. Ring rolling has been simulated using different parameter settings.

Influence of two-stream relativistic electron beam parameters on the space-charge wave with broad frequency spectrum formation

Science.gov (United States)

Alexander, LYSENKO; Iurii, VOLK

2018-03-01

We developed a cubic non-linear theory describing the dynamics of the multiharmonic space-charge wave (SCW), with harmonics frequencies smaller than the two-stream instability critical frequency, with different relativistic electron beam (REB) parameters. The self-consistent differential equation system for multiharmonic SCW harmonic amplitudes was elaborated in a cubic non-linear approximation. This system considers plural three-wave parametric resonant interactions between wave harmonics and the two-stream instability effect. Different REB parameters such as the input angle with respect to focusing magnetic field, the average relativistic factor value, difference of partial relativistic factors, and plasma frequency of partial beams were investigated regarding their influence on the frequency spectrum width and multiharmonic SCW saturation levels. We suggested ways in which the multiharmonic SCW frequency spectrum widths could be increased in order to use them in multiharmonic two-stream superheterodyne free-electron lasers, with the main purpose of forming a powerful multiharmonic electromagnetic wave.

A fractional factorial probabilistic collocation method for uncertainty propagation of hydrologic model parameters in a reduced dimensional space

Science.gov (United States)

Wang, S.; Huang, G. H.; Huang, W.; Fan, Y. R.; Li, Z.

2015-10-01

In this study, a fractional factorial probabilistic collocation method is proposed to reveal statistical significance of hydrologic model parameters and their multi-level interactions affecting model outputs, facilitating uncertainty propagation in a reduced dimensional space. The proposed methodology is applied to the Xiangxi River watershed in China to demonstrate its validity and applicability, as well as its capability of revealing complex and dynamic parameter interactions. A set of reduced polynomial chaos expansions (PCEs) only with statistically significant terms can be obtained based on the results of factorial analysis of variance (ANOVA), achieving a reduction of uncertainty in hydrologic predictions. The predictive performance of reduced PCEs is verified by comparing against standard PCEs and the Monte Carlo with Latin hypercube sampling (MC-LHS) method in terms of reliability, sharpness, and Nash-Sutcliffe efficiency (NSE). Results reveal that the reduced PCEs are able to capture hydrologic behaviors of the Xiangxi River watershed, and they are efficient functional representations for propagating uncertainties in hydrologic predictions.

Charting the Parameter Space of the 21-cm Power Spectrum

Science.gov (United States)

Cohen, Aviad; Fialkov, Anastasia; Barkana, Rennan

2018-05-01

The high-redshift 21-cm signal of neutral hydrogen is expected to be observed within the next decade and will reveal epochs of cosmic evolution that have been previously inaccessible. Due to the lack of observations, many of the astrophysical processes that took place at early times are poorly constrained. In recent work we explored the astrophysical parameter space and the resulting large variety of possible global (sky-averaged) 21-cm signals. Here we extend our analysis to the fluctuations in the 21-cm signal, accounting for those introduced by density and velocity, Lyα radiation, X-ray heating, and ionization. While the radiation sources are usually highlighted, we find that in many cases the density fluctuations play a significant role at intermediate redshifts. Using both the power spectrum and its slope, we show that properties of high-redshift sources can be extracted from the observable features of the fluctuation pattern. For instance, the peak amplitude of ionization fluctuations can be used to estimate whether heating occurred early or late and, in the early case, to also deduce the cosmic mean ionized fraction at that time. The slope of the power spectrum has a more universal redshift evolution than the power spectrum itself and can thus be used more easily as a tracer of high-redshift astrophysics. Its peaks can be used, for example, to estimate the redshift of the Lyα coupling transition and the redshift of the heating transition (and the mean gas temperature at that time). We also show that a tight correlation is predicted between features of the power spectrum and of the global signal, potentially yielding important consistency checks.

Linear and non-linear Modified Gravity forecasts with future surveys

Science.gov (United States)

Casas, Santiago; Kunz, Martin; Martinelli, Matteo; Pettorino, Valeria

2017-12-01

Modified Gravity theories generally affect the Poisson equation and the gravitational slip in an observable way, that can be parameterized by two generic functions (η and μ) of time and space. We bin their time dependence in redshift and present forecasts on each bin for future surveys like Euclid. We consider both Galaxy Clustering and Weak Lensing surveys, showing the impact of the non-linear regime, with two different semi-analytical approximations. In addition to these future observables, we use a prior covariance matrix derived from the Planck observations of the Cosmic Microwave Background. In this work we neglect the information from the cross correlation of these observables, and treat them as independent. Our results show that η and μ in different redshift bins are significantly correlated, but including non-linear scales reduces or even eliminates the correlation, breaking the degeneracy between Modified Gravity parameters and the overall amplitude of the matter power spectrum. We further apply a Zero-phase Component Analysis and identify which combinations of the Modified Gravity parameter amplitudes, in different redshift bins, are best constrained by future surveys. We extend the analysis to two particular parameterizations of μ and η and consider, in addition to Euclid, also SKA1, SKA2, DESI: we find in this case that future surveys will be able to constrain the current values of η and μ at the 2-5% level when using only linear scales (wavevector k < 0 . 15 h/Mpc), depending on the specific time parameterization; sensitivity improves to about 1% when non-linearities are included.

AGN Accretion Physics in the Time Domain: Survey Cadences, Stochastic Analysis, and Physical Interpretations

Science.gov (United States)

Moreno, Jackeline; Vogeley, Michael S.; Richards, Gordon; O'Brien, John T.; Kasliwal, Vishal

2018-01-01

We present rigorous testing of survey cadences (K2, SDSS, CRTS, & Pan-STARRS) for quasar variability science using a magnetohydrodynamics synthetic lightcurve and the canonical lightcurve from Kepler, Zw 229.15. We explain where the state of the art is in regards to physical interpretations of stochastic models (CARMA) applied to AGN variability. Quasar variability offers a time domain approach of probing accretion physics at the SMBH scale. Evidence shows that the strongest amplitude changes in the brightness of AGN occur on long timescales ranging from months to hundreds of days. These global behaviors can be constrained by survey data despite low sampling resolution. CARMA processes provide a flexible family of models used to interpolate between data points, predict future observations and describe behaviors in a lightcurve. This is accomplished by decomposing a signal into rise and decay timescales, frequencies for cyclic behavior and shock amplitudes. Characteristic timescales may point to length-scales over which a physical process operates such as turbulent eddies, warping or hotspots due to local thermal instabilities. We present the distribution of SDSS Stripe 82 quasars in CARMA parameters space that pass our cadence tests and also explain how the Damped Harmonic Oscillator model, CARMA(2,1), reduces to the Damped Random Walk, CARMA(1,0), given the data in a specific region of the parameter space.

Large model-space calculation of the nuclear level density parameter

International Nuclear Information System (INIS)

Agrawal, B.K.; Samaddar, S.K.; De, J.N.; Shlomo, S.

1998-01-01

Recently, several attempts have been made to obtain nuclear level density (ρ) and level density parameter (α) within the microscopic approaches based on path integral representation of the partition function. The results for the inverse level density parameter K es and the level density as a function of excitation energy are presented

GMC COLLISIONS AS TRIGGERS OF STAR FORMATION. I. PARAMETER SPACE EXPLORATION WITH 2D SIMULATIONS

Energy Technology Data Exchange (ETDEWEB)

Wu, Benjamin [Department of Physics, University of Florida, Gainesville, FL 32611 (United States); Loo, Sven Van [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Tan, Jonathan C. [Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States); Bruderer, Simon, E-mail: benwu@phys.ufl.edu [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, D-85748 Garching (Germany)

2015-09-20

We utilize magnetohydrodynamic (MHD) simulations to develop a numerical model for giant molecular cloud (GMC)–GMC collisions between nearly magnetically critical clouds. The goal is to determine if, and under what circumstances, cloud collisions can cause pre-existing magnetically subcritical clumps to become supercritical and undergo gravitational collapse. We first develop and implement new photodissociation region based heating and cooling functions that span the atomic to molecular transition, creating a multiphase ISM and allowing modeling of non-equilibrium temperature structures. Then in 2D and with ideal MHD, we explore a wide parameter space of magnetic field strength, magnetic field geometry, collision velocity, and impact parameter and compare isolated versus colliding clouds. We find factors of ∼2–3 increase in mean clump density from typical collisions, with strong dependence on collision velocity and magnetic field strength, but ultimately limited by flux-freezing in 2D geometries. For geometries enabling flow along magnetic field lines, greater degrees of collapse are seen. We discuss observational diagnostics of cloud collisions, focussing on {sup 13}CO(J = 2–1), {sup 13}CO(J = 3–2), and {sup 12}CO(J = 8–7) integrated intensity maps and spectra, which we synthesize from our simulation outputs. We find that the ratio of J = 8–7 to lower-J emission is a powerful diagnostic probe of GMC collisions.

Tracking in Object Action Space

DEFF Research Database (Denmark)

Krüger, Volker; Herzog, Dennis

2013-01-01

the space of the object affordances, i.e., the space of possible actions that are applied on a given object. This way, 3D body tracking reduces to action tracking in the object (and context) primed parameter space of the object affordances. This reduces the high-dimensional joint-space to a low...

Phenomenology of dark energy: exploring the space of theories with future redshift surveys

International Nuclear Information System (INIS)

Piazza, Federico; Steigerwald, Heinrich; Marinoni, Christian

2014-01-01

We use the effective field theory of dark energy to explore the space of modified gravity models which are capable of driving the present cosmic acceleration. We identify five universal functions of cosmic time that are enough to describe a wide range of theories containing a single scalar degree of freedom in addition to the metric. The first function (the effective equation of state) uniquely controls the expansion history of the universe. The remaining four functions appear in the linear cosmological perturbation equations, but only three of them regulate the growth history of large scale structures. We propose a specific parameterization of such functions in terms of characteristic coefficients that serve as coordinates in the space of modified gravity theories and can be effectively constrained by the next generation of cosmological experiments. We address in full generality the problem of the soundness of the theory against ghost-like and gradient instabilities and show how the space of non-pathological models shrinks when a more negative equation of state parameter is considered. This analysis allows us to locate a large class of stable theories that violate the null energy condition (i.e. super-acceleration models) and to recover, as particular subsets, various models considered so far. Finally, under the assumption that the true underlying cosmological model is the Λ Cold Dark Matter (ΛCDM) scenario, and relying on the figure of merit of EUCLID-like observations, we demonstrate that the theoretical requirement of stability significantly narrows the empirical likelihood, increasing the discriminatory power of data. We also find that the vast majority of these non-pathological theories generating the same expansion history as the ΛCDM model predict a different, lower, growth rate of cosmic structures

Planning ahead for asteroid and comet hazard mitigation, phase 1: parameter space exploration and scenario modeling

Energy Technology Data Exchange (ETDEWEB)

Plesko, Catherine S [Los Alamos National Laboratory; Clement, R Ryan [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Bradley, Paul A [Los Alamos National Laboratory; Huebner, Walter F [Los Alamos National Laboratory

2009-01-01

The mitigation of impact hazards resulting from Earth-approaching asteroids and comets has received much attention in the popular press. However, many questions remain about the near-term and long-term, feasibility and appropriate application of all proposed methods. Recent and ongoing ground- and space-based observations of small solar-system body composition and dynamics have revolutionized our understanding of these bodies (e.g., Ryan (2000), Fujiwara et al. (2006), and Jedicke et al. (2006)). Ongoing increases in computing power and algorithm sophistication make it possible to calculate the response of these inhomogeneous objects to proposed mitigation techniques. Here we present the first phase of a comprehensive hazard mitigation planning effort undertaken by Southwest Research Institute and Los Alamos National Laboratory. We begin by reviewing the parameter space of the object's physical and chemical composition and trajectory. We then use the radiation hydrocode RAGE (Gittings et al. 2008), Monte Carlo N-Particle (MCNP) radiation transport (see Clement et al., this conference), and N-body dynamics codes to explore the effects these variations in object properties have on the coupling of energy into the object from a variety of mitigation techniques, including deflection and disruption by nuclear and conventional munitions, and a kinetic impactor.

Path integral of the angular momentum eigenstates evolving with the parameter linked with rotation angle under the space rotation transformation

International Nuclear Information System (INIS)

Zhang Zhongcan; Hu Chenguo; Fang Zhenyun

1998-01-01

The authors study the method which directly adopts the azimuthal angles and the rotation angle of the axis to describe the evolving process of the angular momentum eigenstates under the space rotation transformation. The authors obtain the angular momentum rotation and multi-rotation matrix elements' path integral which evolves with the parameter λ(0→θ,θ the rotation angle), and establish the general method of treating the functional (path) integral as a normal multi-integrals

APPLICATION OF PARAMETER CONTINUATION METHOD FOR INVESTIGATION OF VIBROIMPACT SYSTEMS DYNAMIC BEHAVIOUR. PROBLEM STATE. SHORT SURVEY OF WORLD SCIENTIFIC LITERATURE

Directory of Open Access Journals (Sweden)

V.A. Bazhenov

2014-12-01

Full Text Available Authors in their works study vibroimpact system dynamic behaviour by numerical parametric continuation technique combined with shooting and Newton-Raphson’s methods. The technique is adapted to two-mass two-degree-of-freedom vibroimpact system under periodic excitation. Impact is simulated by nonlinear contact interaction force based on Hertz’s contact theory. Stability or instability of obtained periodic solutions is determined by monodromy matrix eigenvalues (multipliers based on Floquet’s theory. In the present paper we describe the state of problem of parameter continuation method using for nonlinear tasks solution. Also we give the short survey of numerous contemporary literature in English and Russian about parameter continuation method application for nonlinear problems. This method is applied for vibroimpact problem solving more rarely because of the difficulties connected with repeated impacts.

Changes in Periodontal and Microbial Parameters after the Space ...

African Journals Online (AJOL)

Aim: This study aims to evaluate the clinical and microbiological changes accompanying the inflammatory process of periodontal tissues during treatment with space maintainers (SMs). Materials and Methods: The children were separated into fixed (Group 1, n = 20) and removable (Group 2, n = 20) appliance groups.

A survey on the autotuning of PID parameter

International Nuclear Information System (INIS)

Lee, Yoon Hee; Ha, Jae Hong; Sin, Hae Kon; Kim, Dong Wan; Nam, Sang Ku

1996-06-01

A significant advance in science and technology during the last few decades has resulted in the evolution and use of automatic control equipment in various areas of industry. The automatic control equipment monitor various parameters associated with the process and make decisions accordingly. In the area of process control, extensive research has been carried out for PID parameter auto-tunig techniques since the middle of 1980's. This paper covers two auto-tuning techniques namely system transient response performance and experimental method to analyze dynamic characteristics of process systems. In this paper auto-tunig technology used in commercial models is analyzed in detail. It is reported by industry that by optimum application of the auto-tuning controller, the operator load is significantly reduced while the reliability of process control is greatly enhanced. It is recommended that the application of auto-tuning controller should be evaluated for automatic process control in nuclear plant. 4 tabs., 12 figs., 21 refs. (Author)

New tools for evaluating LQAS survey designs

OpenAIRE

Hund, Lauren

2014-01-01

Lot Quality Assurance Sampling (LQAS) surveys have become increasingly popular in global health care applications. Incorporating Bayesian ideas into LQAS survey design, such as using reasonable prior beliefs about the distribution of an indicator, can improve the selection of design parameters and decision rules. In this paper, a joint frequentist and Bayesian framework is proposed for evaluating LQAS classification accuracy and informing survey design parameters. Simple software tools are pr...

Trading Time with Space - Development of subduction zone parameter database for a maximum magnitude correlation assessment

Science.gov (United States)

Schaefer, Andreas; Wenzel, Friedemann

2017-04-01

Subduction zones are generally the sources of the earthquakes with the highest magnitudes. Not only in Japan or Chile, but also in Pakistan, the Solomon Islands or for the Lesser Antilles, subduction zones pose a significant hazard for the people. To understand the behavior of subduction zones, especially to identify their capabilities to produce maximum magnitude earthquakes, various physical models have been developed leading to a large number of various datasets, e.g. from geodesy, geomagnetics, structural geology, etc. There have been various studies to utilize this data for the compilation of a subduction zone parameters database, but mostly concentrating on only the major zones. Here, we compile the largest dataset of subduction zone parameters both in parameter diversity but also in the number of considered subduction zones. In total, more than 70 individual sources have been assessed and the aforementioned parametric data have been combined with seismological data and many more sources have been compiled leading to more than 60 individual parameters. Not all parameters have been resolved for each zone, since the data completeness depends on the data availability and quality for each source. In addition, the 3D down-dip geometry of a majority of the subduction zones has been resolved using historical earthquake hypocenter data and centroid moment tensors where available and additionally compared and verified with results from previous studies. With such a database, a statistical study has been undertaken to identify not only correlations between those parameters to estimate a parametric driven way to identify potentials for maximum possible magnitudes, but also to identify similarities between the sources themselves. This identification of similarities leads to a classification system for subduction zones. Here, it could be expected if two sources share enough common characteristics, other characteristics of interest may be similar as well. This concept

Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame

Science.gov (United States)

Bruni, Sara; Rebischung, Paul; Zerbini, Susanna; Altamimi, Zuheir; Errico, Maddalena; Santi, Efisio

2018-04-01

The realization of the international terrestrial reference frame (ITRF) is currently based on the data provided by four space geodetic techniques. The accuracy of the different technique-dependent materializations of the frame physical parameters (origin and scale) varies according to the nature of the relevant observables and to the impact of technique-specific errors. A reliable computation of the ITRF requires combining the different inputs, so that the strengths of each technique can compensate for the weaknesses of the others. This combination, however, can only be performed providing some additional information which allows tying together the independent technique networks. At present, the links used for that purpose are topometric surveys (local/terrestrial ties) available at ITRF sites hosting instruments of different techniques. In principle, a possible alternative could be offered by spacecrafts accommodating the positioning payloads of multiple geodetic techniques realizing their co-location in orbit (space ties). In this paper, the GNSS-SLR space ties on-board GPS and GLONASS satellites are thoroughly examined in the framework of global reference frame computations. The investigation focuses on the quality of the realized physical frame parameters. According to the achieved results, the space ties on-board GNSS satellites cannot, at present, substitute terrestrial ties in the computation of the ITRF. The study is completed by a series of synthetic simulations investigating the impact that substantial improvements in the volume and quality of SLR observations to GNSS satellites would have on the precision of the GNSS frame parameters.

Cross-Cultural Issues of Intra- and Inter-Organisational Cooperation in Space Operations: A Survey Study with Ground Personnel of the European Space Agency

Science.gov (United States)

Mjeldheim Sandal, Gro; Mjeldheim Sandal, Gro; Manzey, Dietrich

Today's space operations often involve close co-working of people with different ethnical, professional and organizational backgrounds. The aim of the study was to examine the implications of cultural diversity for efficient collaboration within the European Space Agency (ESA), and between ESA employees and representatives from other agencies. Methods: A web-based survey was answered by 905 employees at the European Astronaut Centre and at the European Space Technology Centre. An adapted version of the Flight Management Attitude Questionnaire by Helmreich and Merrit was used. Personnel were also asked about interpersonal and operational issues that interfered with efficient co-working within ESA and in relation to other space agencies. Results: Collaboration within ESA: A descriptive analysis was conducted of the rank orders of challenges perceived by members of different nationalities (the Netherlands (N=68), German (N=138), Italian (N=135), French (N=124), British (N=84) and Scandinavian (27).Rank orders show a surprisingly uniformity across nationalities. Most respondents perceived differences in the preferred leadership style as the main challenge for co-working in multi-national groups followed by differences in dealing with conflicts and misunderstandings. In contrast communication problems due different languages and differences in non-verbal behaviour, as well as differences in gender stereotypes were among the lowest rated issues. However, Scandinavian respondents showed a different pattern from other nationalities. Collaboration between agencies: The most significant issues reported to interfere with the efficiency of inter-agency collaboration varied. Most difficulties were reported in relation to clarity of communication, insufficient sharing of task related information, understanding the process of decision making in partner organization, and authoritarian leadership style in the partner organization Conclusion: Cultural differences in leadership and

The linear parameters and the decoupling matrix for linearly coupled motion in 6 dimensional phase space

International Nuclear Information System (INIS)

Parzen, G.

1997-01-01

It will be shown that starting from a coordinate system where the 6 phase space coordinates are linearly coupled, one can go to a new coordinate system, where the motion is uncoupled, by means of a linear transformation. The original coupled coordinates and the new uncoupled coordinates are related by a 6 x 6 matrix, R. It will be shown that of the 36 elements of the 6 x 6 decoupling matrix R, only 12 elements are independent. A set of equations is given from which the 12 elements of R can be computed form the one period transfer matrix. This set of equations also allows the linear parameters, the β i , α i , i = 1, 3, for the uncoupled coordinates, to be computed from the one period transfer matrix

Parameter spaces for linear and nonlinear whistler-mode waves

International Nuclear Information System (INIS)

Summers, Danny; Tang, Rongxin; Omura, Yoshiharu; Lee, Dong-Hun

2013-01-01

We examine the growth of magnetospheric whistler-mode waves which comprises a linear growth phase followed by a nonlinear growth phase. We construct time-profiles for the wave amplitude that smoothly match at the transition between linear and nonlinear wave growth. This matching procedure can only take place over a limited “matching region” in (N h /N 0 ,A T )-space, where A T is the electron thermal anisotropy, N h is the hot (energetic) electron number density, and N 0 is the cold (background) electron number density. We construct this matching region and determine how the matching wave amplitude varies throughout the region. Further, we specify a boundary in (N h /N 0 ,A T )-space that separates a region where only linear chorus wave growth can occur from the region in which fully nonlinear chorus growth is possible. We expect that this boundary should prove of practical use in performing computationally expensive full-scale particle simulations, and in interpreting experimental wave data

Nash equilibria in quantum games with generalized two-parameter strategies

International Nuclear Information System (INIS)

Flitney, Adrian P.; Hollenberg, Lloyd C.L.

2007-01-01

In the Eisert protocol for 2x2 quantum games [J. Eisert, et al., Phys. Rev. Lett. 83 (1999) 3077], a number of authors have investigated the features arising from making the strategic space a two-parameter subset of single qubit unitary operators. We argue that the new Nash equilibria and the classical-quantum transitions that occur are simply an artifact of the particular strategy space chosen. By choosing a different, but equally plausible, two-parameter strategic space we show that different Nash equilibria with different classical-quantum transitions can arise. We generalize the two-parameter strategies and also consider these strategies in a multiplayer setting

From Discrete Space-Time to Minkowski Space: Basic Mechanisms, Methods and Perspectives

Science.gov (United States)

Finster, Felix

This survey article reviews recent results on fermion systems in discrete space-time and corresponding systems in Minkowski space. After a basic introduction to the discrete setting, we explain a mechanism of spontaneous symmetry breaking which leads to the emergence of a discrete causal structure. As methods to study the transition between discrete space-time and Minkowski space, we describe a lattice model for a static and isotropic space-time, outline the analysis of regularization tails of vacuum Dirac sea configurations, and introduce a Lorentz invariant action for the masses of the Dirac seas. We mention the method of the continuum limit, which allows to analyze interacting systems. Open problems are discussed.

On the structure of physical space

CERN Document Server

Wisnivesky, D

2001-01-01

In this paper we develop a theory based on the postulate that the environment where physical phenomena take place is the space of four complex parameters of the linear group of transformations. Using these parameters as fundamental building blocks we construct ordinary space-time and the internal space. Lorentz invariance is built in the definition of external space, while the symmetry of the internal space, S(1)*SU(2) results as a consequence of the identification of the external coordinates. Thus, special relativity and the electroweak interaction symmetry ensue from the properties of the basic building blocks of physical space. Since internal and external space are derived from a common structure, there is no need to bring into the theory any additional hypothesis to account for the microscopic nature of the internal space, nor to introduce symmetry breaking mechanisms that would normally be required to force a splitting of the internal and external symmetries. As an outcome of the existence of a basic str...

Geographic information technology monitoring and mapping of coal fires in Ukraine, according to the space survey

Energy Technology Data Exchange (ETDEWEB)

Pivnyak, G.; Busygin, B.; Garkusha, I. [National Mining Univ., Dnipropetrovsk (Ukraine)

2010-07-01

Coal fires are a significant problem around the world, particularly in China, India, and the United States. Coal fires burn thousands of tons of coal reserves and lead to serious problems for the environment, degradation and destruction of landscape, and harm public health. Technology, such as spectrology analysis of signatures with high temperature activity can be used to calculate vegetation algorithms and soil indexes, and multispectral survey data in the thermal channels of scanners. This paper presented the perspectives of technology development in coal fires and the approach to the detection, monitoring, and quantitative estimation of coal fires by the instruments using geographic information systems. Specifically, the paper considered the use of coal fire fragment monitoring technology from data of a diachronous survey obtained by Landsat satellites, to classify dangerous coal waste banks of the Donbass Mine located in Ukraine. The paper provided a description of the study area and discussed the detection technology of temperature-active waste banks. It was concluded that geoinformation technology provides an opportunity to effectively mark mining dumps, in particular, waste banks in multispectrum space images made by Landsat satellites. 7 refs., 6 figs.

Post-Newtonian evolution of massive black hole triplets in galactic nuclei - II. Survey of the parameter space

Science.gov (United States)

Bonetti, Matteo; Haardt, Francesco; Sesana, Alberto; Barausse, Enrico

2018-04-01

Massive black hole binaries (MBHBs) are expected to form at the centre of merging galaxies during the hierarchical assembly of the cosmic structure, and are expected to be the loudest sources of gravitational waves (GWs) in the low frequency domain. However, because of the dearth of energy exchanges with background stars and gas, many of these MBHBs may stall at separations too large for GW emission to drive them to coalescence in less than a Hubble time. Triple MBH systems are then bound to form after a further galaxy merger, triggering a complex and rich dynamics that can eventually lead to MBH coalescence. Here we report on the results of a large set of numerical simulations, where MBH triplets are set in spherical stellar potentials and MBH dynamics is followed through 2.5 post-Newtonian order in the equations of motion. From our full suite of simulated systems we find that a fraction ≃ 20 - 30 % of the MBH binaries that would otherwise stall are led to coalesce within a Hubble time. The corresponding coalescence timescale peaks around 300 Myr, while the eccentricity close to the plunge, albeit small, is non-negligible (≲ 0.1). We construct and discuss marginalised probability distributions of the main parameters involved and, in a companion paper of the series, we will use the results presented here to forecast the contribution of MBH triplets to the GW signal in the nHz regime probed by Pulsar Timing Array experiments.

"A space-time ensemble Kalman filter for state and parameter estimation of groundwater transport models"

Science.gov (United States)

Briseño, Jessica; Herrera, Graciela S.

2010-05-01

Herrera (1998) proposed a method for the optimal design of groundwater quality monitoring networks that involves space and time in a combined form. The method was applied later by Herrera et al (2001) and by Herrera and Pinder (2005). To get the estimates of the contaminant concentration being analyzed, this method uses a space-time ensemble Kalman filter, based on a stochastic flow and transport model. When the method is applied, it is important that the characteristics of the stochastic model be congruent with field data, but, in general, it is laborious to manually achieve a good match between them. For this reason, the main objective of this work is to extend the space-time ensemble Kalman filter proposed by Herrera, to estimate the hydraulic conductivity, together with hydraulic head and contaminant concentration, and its application in a synthetic example. The method has three steps: 1) Given the mean and the semivariogram of the natural logarithm of hydraulic conductivity (ln K), random realizations of this parameter are obtained through two alternatives: Gaussian simulation (SGSim) and Latin Hypercube Sampling method (LHC). 2) The stochastic model is used to produce hydraulic head (h) and contaminant (C) realizations, for each one of the conductivity realizations. With these realization the mean of ln K, h and C are obtained, for h and C, the mean is calculated in space and time, and also the cross covariance matrix h-ln K-C in space and time. The covariance matrix is obtained averaging products of the ln K, h and C realizations on the estimation points and times, and the positions and times with data of the analyzed variables. The estimation points are the positions at which estimates of ln K, h or C are gathered. In an analogous way, the estimation times are those at which estimates of any of the three variables are gathered. 3) Finally the ln K, h and C estimate are obtained using the space-time ensemble Kalman filter. The realization mean for each one

The Pan-STARRS1 Surveys

Science.gov (United States)

Chambers, Kenneth; Pan-STARRS Team

2018-01-01

The Pan-STARRS1 Surveys are complete and the first data release, DR1, is available from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The data include a database of measured attributes of 3 billion objects, stacked images, and metadata of the 3pi Steradian Survey. The DR1 contains all stationary objects with mean and stack photometry registered on the GAIA astrometric frame. DR2 is in preparation and will be released this winter with all the individual epoch images and time domain photometry and forced photometry on the individual epoch images. The characteristics of the Pan-STARRS1 Surveys will be presented, including image quality, depth, cadence, and coverage. Measured attributes include PSF model magnitudes, aperture magnitudes, Kron Magnitudes, radial moments, Petrosian magnitudes, DeVaucoulers, Exponential, and Sersic magnitudes for extended objects. Images include total intensity, variance, and masks.An overview of the Pan-STARRS1 Surveys and data releases will be presented together with a brief description of the data collected since the end of the PS1 Science Consortium surveys, and the plans for the upcoming survey with PS1 and PS2 begining in February 2018.

Remote sensing of refractivity from space for global observations of atmospheric parameters

International Nuclear Information System (INIS)

Gorbunov, M.E.; Sokolovskiy, S.V.

1993-01-01

This report presents the first results of computational simulations on the retrieval of meteorological parameters from space refractometric data on the basis of the ECHAM 3 model developed at the Max Planck Institute for Meteorology (Roeckner et al. 1992). For this purpose the grid fields of temperature, geopotential and humidity available from the model were interpolated and a continuous spatial field of refractivity (together with its first derivative) was generated. This field was used for calculating the trajectories of electromagnetic rays for the given orbits of transmitting and receiving satellites and for the determination of the quantities (incident angles or Doppler frequency shifts) being measured at receiving satellite during occultation. These quantities were then used for solving the inverse problem - retrieving the distribution of refractivity in the vicinity of the ray perigees. The retrieved refractivity was used to calculate pressure and temperature (using the hydrostatic equation and the equation of state). The results were compared with initial data, and the retrieval errors were evaluated. The study shows that the refractivity can be retrieved with very high accuracy in particular if a tomographic reconstruction is applied. Effects of humidity and temperature are not separable. Stratospheric temperatures globally and upper tropospheric temperatures at middle and high latitudes can be accurately retrieved, other areas require humidity data. Alternatively humidity data can be retrieved if the temperature fields are known. (orig.)

GESE: a small UV space telescope to conduct a large spectroscopic survey of z˜1 Galaxies

Science.gov (United States)

Heap, Sara R.; Gong, Qian; Hull, Tony; Kruk, Jeffrey; Purves, Lloyd

2014-11-01

One of the key goals of NASA's astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a space mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at a redshift, z˜1 (look-back time of ˜8 billion years). GESE is a 1.5-m space telescope with an ultraviolet (UV) multi-object slit spectrograph that can obtain spectra of hundreds of galaxies per exposure. The spectrograph covers the spectral range, 0.2-0.4 μm at a spectral resolving power, R˜500. This observed spectral range corresponds to 0.1-0.2 μm as emitted by a galaxy at a redshift, z=1. The mission concept takes advantage of two new technological advances: (1) light-weighted, wide-field telescope mirrors, and (2) the Next-Generation MicroShutter Array (NG-MSA) to be used as a slit generator in the multi-object slit spectrograph.

Estimates for Parameter Littlewood-Paley gκ⁎ Functions on Nonhomogeneous Metric Measure Spaces

Directory of Open Access Journals (Sweden)

Guanghui Lu

2016-01-01

Full Text Available Let (X,d,μ be a metric measure space which satisfies the geometrically doubling measure and the upper doubling measure conditions. In this paper, the authors prove that, under the assumption that the kernel of Mκ⁎ satisfies a certain Hörmander-type condition, Mκ⁎,ρ is bounded from Lebesgue spaces Lp(μ to Lebesgue spaces Lp(μ for p≥2 and is bounded from L1(μ into L1,∞(μ. As a corollary, Mκ⁎,ρ is bounded on Lp(μ for 1space H1(μ into the Lebesgue space L1(μ.

Spin Hall effect on a noncommutative space

International Nuclear Information System (INIS)

Ma Kai; Dulat, Sayipjamal

2011-01-01

We study the spin-orbital interaction and the spin Hall effect of an electron moving on a noncommutative space under the influence of a vector potential A(vector sign). On a noncommutative space, we find that the commutator between the vector potential A(vector sign) and the electric potential V 1 (r(vector sign)) of the lattice induces a new term, which can be treated as an effective electric field, and the spin Hall conductivity obtains some correction. On a noncommutative space, the spin current and spin Hall conductivity have distinct values in different directions, and depend explicitly on the noncommutative parameter. Once this spin Hall conductivity in different directions can be measured experimentally with a high level of accuracy, the data can then be used to impose bounds on the value of the space noncommutativity parameter. We have also defined a new parameter, σ=ρθ (ρ is the electron concentration, θ is the noncommutativity parameter), which can be measured experimentally. Our approach is based on the Foldy-Wouthuysen transformation, which gives a general Hamiltonian of a nonrelativistic electron moving on a noncommutative space.

New tools for evaluating LQAS survey designs.

Science.gov (United States)

Hund, Lauren

2014-02-15

Lot Quality Assurance Sampling (LQAS) surveys have become increasingly popular in global health care applications. Incorporating Bayesian ideas into LQAS survey design, such as using reasonable prior beliefs about the distribution of an indicator, can improve the selection of design parameters and decision rules. In this paper, a joint frequentist and Bayesian framework is proposed for evaluating LQAS classification accuracy and informing survey design parameters. Simple software tools are provided for calculating the positive and negative predictive value of a design with respect to an underlying coverage distribution and the selected design parameters. These tools are illustrated using a data example from two consecutive LQAS surveys measuring Oral Rehydration Solution (ORS) preparation. Using the survey tools, the dependence of classification accuracy on benchmark selection and the width of the 'grey region' are clarified in the context of ORS preparation across seven supervision areas. Following the completion of an LQAS survey, estimation of the distribution of coverage across areas facilitates quantifying classification accuracy and can help guide intervention decisions.

Global and nonglobal parameters of horizontal-branch morphology of globular clusters

International Nuclear Information System (INIS)

Milone, A. P.; Marino, A. F.; Dotter, A.; Norris, J. E.; Jerjen, H.; Asplund, M.

2014-01-01

The horizontal-branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost the same metallicity exhibit different HB morphologies demonstrates that at least one more parameter is needed to explain the HB morphology. It has been suggested that one of these should be a global parameter that varies from GC to GC and the other a nonglobal parameter that varies within the GC. In this study we provide empirical evidence corroborating this idea. We used the photometric catalogs obtained with the Advanced Camera for Surveys of the Hubble Space Telescope and analyze the color-magnitude diagrams of 74 GCs. The HB morphology of our sample of GCs has been investigated on the basis of the two new parameters L1 and L2 that measure the distance between the red giant branch and the coolest part of the HB and the color extension of the HB, respectively. We find that L1 correlates with both metallicity and age, whereas L2 most strongly correlates with the mass of the hosting GC. The range of helium abundance among the stars in a GC, characterized by ΔY and associated with the presence of multiple stellar populations, has been estimated in a few GCs to date. In these GCs we find a close relationship among ΔY, GC mass, and L2. We conclude that age and metallicity are the main global parameters, while the range of helium abundance within a GC is the main nonglobal parameter defining the HB morphology of Galactic GCs.

Astrophysical parameters of ten poorly studied open star clusters

International Nuclear Information System (INIS)

Tadross, Ashraf Latif; El-Bendary, Reda; Osman, Anas; Ismail, Nader; Bakry, Abdel Aziz

2012-01-01

We present the fundamental parameters of ten open star clusters, nominated from Kronberger et al. who presented some newly discovered stellar groups on the basis of the Two Micron All Sky Survey photometry and Digitized Sky Survey visual images. Star counts and photometric parameters (radius, membership, distance, color excess, age, luminosity function, mass function, total mass, and dynamical relaxation time) have been determined for these ten clusters for the first time. In order to calibrate our procedures, the main parameters (distance, age, and color excess) have been re-estimated for another five clusters, which are also studied by Kronberger et al. (research papers)

Effective Theory of Dark Energy at Redshift Survey Scales

CERN Document Server

Gleyzes, Jérôme; Mancarella, Michele; Vernizzi, Filippo

2016-01-01

We explore the phenomenological consequences of general late-time modifications of gravity in the quasi-static approximation, in the case where cold dark matter is non-minimally coupled to the gravitational sector. Assuming spectroscopic and photometric surveys with configuration parameters similar to those of the Euclid mission, we derive constraints on our effective description from three observables: the galaxy power spectrum in redshift space, tomographic weak-lensing shear power spectrum and the correlation spectrum between the integrated Sachs-Wolfe effect and the galaxy distribution. In particular, with $\\Lambda$CDM as fiducial model and a specific choice for the time dependence of our effective functions, we perform a Fisher matrix analysis and find that the unmarginalized $68\\%$ CL errors on the parameters describing the modifications of gravity are of order $\\sigma\\sim10^{-2}$--$10^{-3}$. We also consider two other fiducial models. A nonminimal coupling of CDM enhances the effects of modified gravit...

Dark Energy Survey Year 1 Results: Multi-Probe Methodology and Simulated Likelihood Analyses

Energy Technology Data Exchange (ETDEWEB)

Krause, E.; et al.

2017-06-28

We present the methodology for and detail the implementation of the Dark Energy Survey (DES) 3x2pt DES Year 1 (Y1) analysis, which combines configuration-space two-point statistics from three different cosmological probes: cosmic shear, galaxy-galaxy lensing, and galaxy clustering, using data from the first year of DES observations. We have developed two independent modeling pipelines and describe the code validation process. We derive expressions for analytical real-space multi-probe covariances, and describe their validation with numerical simulations. We stress-test the inference pipelines in simulated likelihood analyses that vary 6-7 cosmology parameters plus 20 nuisance parameters and precisely resemble the analysis to be presented in the DES 3x2pt analysis paper, using a variety of simulated input data vectors with varying assumptions. We find that any disagreement between pipelines leads to changes in assigned likelihood $\\Delta \\chi^2 \\le 0.045$ with respect to the statistical error of the DES Y1 data vector. We also find that angular binning and survey mask do not impact our analytic covariance at a significant level. We determine lower bounds on scales used for analysis of galaxy clustering (8 Mpc$~h^{-1}$) and galaxy-galaxy lensing (12 Mpc$~h^{-1}$) such that the impact of modeling uncertainties in the non-linear regime is well below statistical errors, and show that our analysis choices are robust against a variety of systematics. These tests demonstrate that we have a robust analysis pipeline that yields unbiased cosmological parameter inferences for the flagship 3x2pt DES Y1 analysis. We emphasize that the level of independent code development and subsequent code comparison as demonstrated in this paper is necessary to produce credible constraints from increasingly complex multi-probe analyses of current data.

Tsirelson's space

CERN Document Server

Casazza, Peter G

1989-01-01

This monograph provides a structure theory for the increasingly important Banach space discovered by B.S. Tsirelson. The basic construction should be accessible to graduate students of functional analysis with a knowledge of the theory of Schauder bases, while topics of a more advanced nature are presented for the specialist. Bounded linear operators are studied through the use of finite-dimensional decompositions, and complemented subspaces are studied at length. A myriad of variant constructions are presented and explored, while open questions are broached in almost every chapter. Two appendices are attached: one dealing with a computer program which computes norms of finitely-supported vectors, while the other surveys recent work on weak Hilbert spaces (where a Tsirelson-type space provides an example).

Kinematic modeling of the Milky Way using the RAVE and GCS stellar surveys

Energy Technology Data Exchange (ETDEWEB)

Sharma, S.; Bland-Hawthorn, J. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Binney, J. [Rudolf Peierls Center for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Freeman, K. C. [RSAA Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, Canberra, ACT 72611 (Australia); Steinmetz, M.; Williams, M. E. K. [Leibniz Institut für Astrophysik Potsdam (AIP), An der Sterwarte 16, D-14482 Potsdam (Germany); Boeche, C.; Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, D-69120 Heidelberg (Germany); Bienaymé, O.; Siebert, A. [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, F-67000 Strasbourg (France); Gibson, B. K. [Jeremiah Horrocks Institute for Astrophysics and Super-computing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gilmore, G. F.; Kordopatis, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen (Netherlands); Munari, U. [INAF-Astronomical Observatory of Padova, I-36012 Asiago (VI) (Italy); Navarro, J. F. [University of Victoria, P.O. Box 3055, Station CSC, Victoria, BC V8W 3P6 (Canada); Parker, Q. A.; Reid, W. A. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking RH5 6NT (United Kingdom); Watson, F. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia); and others

2014-09-20

We investigate the kinematic parameters of the Milky Way disk using the Radial Velocity Experiment (RAVE) and Geneva-Copenhagen Survey (GCS) stellar surveys. We do this by fitting a kinematic model to the data and taking the selection function of the data into account. For stars in the GCS we use all phase-space coordinates, but for RAVE stars we use only (ℓ, b, v {sub los}). Using the Markov Chain Monte Carlo technique, we investigate the full posterior distributions of the parameters given the data. We investigate the age-velocity dispersion relation for the three kinematic components (σ {sub R}, σ{sub φ}, σ {sub z}), the radial dependence of the velocity dispersions, the solar peculiar motion (U {sub ☉}, V {sub ☉}, W {sub ☉}), the circular speed Θ{sub 0} at the Sun, and the fall of mean azimuthal motion with height above the midplane. We confirm that the Besançon-style Gaussian model accurately fits the GCS data but fails to match the details of the more spatially extended RAVE survey. In particular, the Shu distribution function (DF) handles noncircular orbits more accurately and provides a better fit to the kinematic data. The Gaussian DF not only fits the data poorly but systematically underestimates the fall of velocity dispersion with radius. The radial scale length of the velocity dispersion profile of the thick disk was found to be smaller than that of the thin disk. We find that correlations exist between a number of parameters, which highlights the importance of doing joint fits. The large size of the RAVE survey allows us to get precise values for most parameters. However, large systematic uncertainties remain, especially in V {sub ☉} and Θ{sub 0}. We find that, for an extended sample of stars, Θ{sub 0} is underestimated by as much as 10% if the vertical dependence of the mean azimuthal motion is neglected. Using a simple model for vertical dependence of kinematics, we find that it is possible to match the Sgr A* proper motion without

Nucleon-deuteron low energy parameters

International Nuclear Information System (INIS)

Zankel, H.; Mathelitsch, L.

1983-01-01

Momentum space Fadeev equations are solved for nucleon-deuteron scattering and effective range parameters are calculated. A reverse trend is found in the two spin states by 4 asub(nd) 4 asub(pd) and 2 asub(pd) 2 asub(nd) which is in agreement with a configuration space calculation, but in conflict with all existing experiments. The Coulomb contributions to the effective range are small in quartet but sizeable in doublet scattering. (Author)

Calculation of the level density parameter using semi-classical approach

International Nuclear Information System (INIS)

Canbula, B.; Babacan, H.

2011-01-01

The level density parameters (level density parameter a and energy shift δ) for back-shifted Fermi gas model have been determined for 1136 nuclei for which complete level scheme is available. Level density parameter is calculated by using the semi-classical single particle level density, which can be obtained analytically through spherical harmonic oscillator potential. This method also enables us to analyze the Coulomb potential's effect on the level density parameter. The dependence of this parameter on energy has been also investigated. Another parameter, δ, is determined by fitting of the experimental level scheme and the average resonance spacings for 289 nuclei. Only level scheme is used for optimization procedure for remaining 847 nuclei. Level densities for some nuclei have been calculated by using these parameter values. Obtained results have been compared with the experimental level scheme and the resonance spacing data.

Infrared Sky Surveys

Science.gov (United States)

Price, Stephan D.

2009-02-01

A retrospective is given on infrared sky surveys from Thomas Edison’s proposal in the late 1870s to IRAS, the first sensitive mid- to far-infrared all-sky survey, and the mid-1990s experiments that filled in the IRAS deficiencies. The emerging technology for space-based surveys is highlighted, as is the prominent role the US Defense Department, particularly the Air Force, played in developing and applying detector and cryogenic sensor advances to early mid-infrared probe-rocket and satellite-based surveys. This technology was transitioned to the infrared astronomical community in relatively short order and was essential to the success of IRAS, COBE and ISO. Mention is made of several of the little known early observational programs that were superseded by more successful efforts.

Harmonic analysis on reductive symmetric spaces

NARCIS (Netherlands)

Ban, E.P. van den; Schlichtkrull, H.

2000-01-01

We give a relatively non-technical survey of some recent advances in the Fourier theory for semisimple symmetric spaces. There are three major results: An inversion formula for the Fourier transform, a Palley-Wiener theorem, which describes the Fourier image of the space of completely supported

Redshift-space distortions from vector perturbations

Science.gov (United States)

Bonvin, Camille; Durrer, Ruth; Khosravi, Nima; Kunz, Martin; Sawicki, Ignacy

2018-02-01

We compute a general expression for the contribution of vector perturbations to the redshift space distortion of galaxy surveys. We show that they contribute to the same multipoles of the correlation function as scalar perturbations and should thus in principle be taken into account in data analysis. We derive constraints for next-generation surveys on the amplitude of two sources of vector perturbations, namely non-linear clustering and topological defects. While topological defects leave a very small imprint on redshift space distortions, we show that the multipoles of the correlation function are sensitive to vorticity induced by non-linear clustering. Therefore future redshift surveys such as DESI or the SKA should be capable of measuring such vector modes, especially with the hexadecapole which appears to be the most sensitive to the presence of vorticity.

Displacement in the parameter space versus spurious solution of discretization with large time step

International Nuclear Information System (INIS)

Mendes, Eduardo; Letellier, Christophe

2004-01-01

In order to investigate a possible correspondence between differential and difference equations, it is important to possess discretization of ordinary differential equations. It is well known that when differential equations are discretized, the solution thus obtained depends on the time step used. In the majority of cases, such a solution is considered spurious when it does not resemble the expected solution of the differential equation. This often happens when the time step taken into consideration is too large. In this work, we show that, even for quite large time steps, some solutions which do not correspond to the expected ones are still topologically equivalent to solutions of the original continuous system if a displacement in the parameter space is considered. To reduce such a displacement, a judicious choice of the discretization scheme should be made. To this end, a recent discretization scheme, based on the Lie expansion of the original differential equations, proposed by Monaco and Normand-Cyrot will be analysed. Such a scheme will be shown to be sufficient for providing an adequate discretization for quite large time steps compared to the pseudo-period of the underlying dynamics

Climate and energy use in glazed spaces

Energy Technology Data Exchange (ETDEWEB)

Wall, M.

1996-11-01

One objective of the thesis has been to elucidate the relationship between building design and the climate, thermal comfort and energy requirements in different types of glazed spaces. Another object has been to study the effect of the glazed spaces on energy requirements in adjacent buildings. It has also been the object to develop a simple calculation method for the assessment of temperatures and energy requirements in glazed spaces. The research work has mainly comprised case studies of existing buildings with glazed spaces and energy balance calculations using both the developed steady-state method and a dynamic building energy simulation program. Parameters such as the geometry of the building, type of glazing, orientation, thermal inertia, airtightness, ventilation system and sunshades have been studied. These parameters are of different importance for each specific type of glazed space. In addition, the significance of each of these parameters varies for different types of glazed spaces. The developed calculation method estimates the minimum and mean temperature in glazed spaces and the energy requirements for heating and cooling. The effect of the glazed space on the energy requirement of the surrounding buildings can also be estimated. It is intended that the method should be applied during the preliminary design stage so that the effect which the design of the building will have on climate and energy requirement may be determined. The method may provide an insight into how glazed spaces behave with regard to climate and energy. 99 refs

Interrelated experiments in laboratory and space plasmas

International Nuclear Information System (INIS)

Koepke, M. E.

2005-01-01

Many advances in understanding space plasma phenomena have been linked to insight derived from theoretical modelling and/or laboratory experiments. Here are discussed advances for which laboratory experiments played an important role. How the interpretation of the space plasma data was influenced by one or more laboratory experiments is described. The space-motivation of laboratory investigations and the scaling of laboratory plasma parameters to space plasma conditions are discussed. Examples demonstrating how laboratory experiments develop physical insight, benchmark theoretical models, discover unexpected behaviour, establish observational signatures, and pioneer diagnostic methods for the space community are presented. The various device configurations found in space-related laboratory investigations are outlined. A primary objective of this review is to articulate the overlapping scientific issues that are addressable in space and lab experiments. A secondary objective is to convey the wide range of laboratory and space plasma experiments involved in this interdisciplinary alliance. The interrelation ship between plasma experiments in the laboratory and in space has a long history, with numerous demonstrations of the benefits afforded the space community by laboratory results. An experiment's suitability and limitations for investigating space processes can be quantitatively established using dimensionless parameters. Even with a partial match of these parameters, aspects of waves, instabilities, nonlinearities, particle transport, reconnection, and hydrodynamics are addressable in a way useful to observers and modelers of space phenomena. Because diagnostic access to space plasmas, laboratory-experimentalists awareness of space phenomena, and efforts by theorists and funding agencies to help scientists bridge the gap between the space and laboratory communities are increasing, the range of laboratory and space plasma experiments with overlapping scientific

Space Shuttle and Space Station Radio Frequency (RF) Exposure Analysis

Science.gov (United States)

Hwu, Shian U.; Loh, Yin-Chung; Sham, Catherine C.; Kroll, Quin D.

2005-01-01

This paper outlines the modeling techniques and important parameters to define a rigorous but practical procedure that can verify the compliance of RF exposure to the NASA standards for astronauts and electronic equipment. The electromagnetic modeling techniques are applied to analyze RF exposure in Space Shuttle and Space Station environments with reasonable computing time and resources. The modeling techniques are capable of taking into account the field interactions with Space Shuttle and Space Station structures. The obtained results illustrate the multipath effects due to the presence of the space vehicle structures. It's necessary to include the field interactions with the space vehicle in the analysis for an accurate assessment of the RF exposure. Based on the obtained results, the RF keep out zones are identified for appropriate operational scenarios, flight rules and necessary RF transmitter constraints to ensure a safe operating environment and mission success.

Quarry Haul Road Ecological Survey

International Nuclear Information System (INIS)

1992-09-01

This biological survey was performed to document the summer flora and fauna found along the haul road constructed as part of the remedial action for the quarry bulk waste. State and Federal species listed as threatened or endangered were noted if encountered while surveying. Sampling locations were equally spaced along the quarry haul road, and a survey for vegetation and birds conducted at each location. Bird observations were conducted as breeding bird surveys once in June of 1991, and again in June of 1992. Each year's survey includes two observations in the early morning and one late in the evening. Vegetation surveys were conducted in 1991 using quadrants and transects. mammal, reptile, and amphibian sightings were noted as encountered

Transport regimes spanning magnetization-coupling phase space

Science.gov (United States)

Baalrud, Scott D.; Daligault, Jérôme

2017-10-01

The manner in which transport properties vary over the entire parameter-space of coupling and magnetization strength is explored. Four regimes are identified based on the relative size of the gyroradius compared to other fundamental length scales: the collision mean free path, Debye length, distance of closest approach, and interparticle spacing. Molecular dynamics simulations of self-diffusion and temperature anisotropy relaxation spanning the parameter space are found to agree well with the predicted boundaries. Comparison with existing theories reveals regimes where they succeed, where they fail, and where no theory has yet been developed.

Compliance evaluation of removable space maintainer or space regainer usage

Directory of Open Access Journals (Sweden)

Revanti Ramadhani

2018-01-01

Full Text Available Premature loss could cause a problem with the tooth arrangement or the dental arch size. A space left by the primary tooth loss could cause migration of the adjacent teeth. As a result, space will be narrowed and undermined the eruption of the permanent teeth. The success of the space maintainer or space regainer usage due to the premature loss marked by space for the replacement of the permanent teeth. The purpose of this research was to evaluate the compliance of children in wearing a space maintainer or space regainer after insertion at Pedodontics Installation of Faculty of Dentistry Universitas Padjadjaran Dental Hospital, Bandung, Indonesia. The research method was descriptive survey technique. The sample consisted of 30 patients selected using the total sampling technique. Data were obtained with a questionnaire and statistically analyzed. The results showed that majority of the children uses the removable space maintainer or the space regainer daily was only about 23,3% overall. Most of the children only use the removable space maintainer or the space regainer for sometimes. The research concluded that the low rate of pedodontic patients compliance at Pedodontics Installation of Faculty of Dentistry Universitas Padjadjaran Dental Hospital in the usage of the removable space maintainer or the space regainer was usually caused by pain or discomfort. This fact was evidence of a low awareness of parents in preventing malocclusion to their children.

A statistical model for estimation of fish density including correlation in size, space, time and between species from research survey data.

Directory of Open Access Journals (Sweden)

J Rasmus Nielsen

Full Text Available Trawl survey data with high spatial and seasonal coverage were analysed using a variant of the Log Gaussian Cox Process (LGCP statistical model to estimate unbiased relative fish densities. The model estimates correlations between observations according to time, space, and fish size and includes zero observations and over-dispersion. The model utilises the fact the correlation between numbers of fish caught increases when the distance in space and time between the fish decreases, and the correlation between size groups in a haul increases when the difference in size decreases. Here the model is extended in two ways. Instead of assuming a natural scale size correlation, the model is further developed to allow for a transformed length scale. Furthermore, in the present application, the spatial- and size-dependent correlation between species was included. For cod (Gadus morhua and whiting (Merlangius merlangus, a common structured size correlation was fitted, and a separable structure between the time and space-size correlation was found for each species, whereas more complex structures were required to describe the correlation between species (and space-size. The within-species time correlation is strong, whereas the correlations between the species are weaker over time but strong within the year.

Regulation of NF-κB oscillation by spatial parameters in true intracellular space (TiCS)

Science.gov (United States)

Ohshima, Daisuke; Sagara, Hiroshi; Ichikawa, Kazuhisa

2013-10-01

Transcription factor NF-κB is activated by cytokine stimulation, viral infection, or hypoxic environment leading to its translocation to the nucleus. The nuclear NF-κB is exported from the nucleus to the cytoplasm again, and by repetitive import and export, NF-κB shows damped oscillation with the period of 1.5-2.0 h. Oscillation pattern of NF-κB is thought to determine the gene expression profile. We published a report on a computational simulation for the oscillation of nuclear NF-κB in a 3D spherical cell, and showed the importance of spatial parameters such as diffusion coefficient and locus of translation for determining the oscillation pattern. Although the value of diffusion coefficient is inherent to protein species, its effective value can be modified by organelle crowding in intracellular space. Here we tested this possibility by computer simulation. The results indicate that the effective value of diffusion coefficient is significantly changed by the organelle crowding, and this alters the oscillation pattern of nuclear NF-κB.

Adaptive Parameter Estimation of Person Recognition Model in a Stochastic Human Tracking Process

Science.gov (United States)

Nakanishi, W.; Fuse, T.; Ishikawa, T.

2015-05-01

This paper aims at an estimation of parameters of person recognition models using a sequential Bayesian filtering method. In many human tracking method, any parameters of models used for recognize the same person in successive frames are usually set in advance of human tracking process. In real situation these parameters may change according to situation of observation and difficulty level of human position prediction. Thus in this paper we formulate an adaptive parameter estimation using general state space model. Firstly we explain the way to formulate human tracking in general state space model with their components. Then referring to previous researches, we use Bhattacharyya coefficient to formulate observation model of general state space model, which is corresponding to person recognition model. The observation model in this paper is a function of Bhattacharyya coefficient with one unknown parameter. At last we sequentially estimate this parameter in real dataset with some settings. Results showed that sequential parameter estimation was succeeded and were consistent with observation situations such as occlusions.

Interval Routing and Minor-Monotone Graph Parameters

NARCIS (Netherlands)

Bakker, E.M.; Bodlaender, H.L.; Tan, R.B.; Leeuwen, J. van

2006-01-01

We survey a number of minor-monotone graph parameters and their relationship to the complexity of routing on graphs. In particular we compare the interval routing parameters κslir(G) and κsir(G) with Colin de Verdi`ere’s graph invariant μ(G) and its variants λ(G) and κ(G). We show that for all the

An integrated system for conducting radiological surveys of contaminated sites - 16312

International Nuclear Information System (INIS)

McCown, Jay P.; Rogers, Donna M.; Waggoner, Charles A.

2009-01-01

This paper describes an integrated detection system that has been developed to conduct radiological surveys of sites suspected of contamination of materials such as depleted uranium. This system utilizes cerium activated lanthanum bromide and thallium activated sodium iodide gamma detectors and can be easily adapted to include units for detecting neutrons. The detection system includes software controlling the collection of radiological spectra and GPS data. Two different platforms are described for conducting surveys, a modified zero turn radius (ZTR) mower and a three-wheeled cart that is manually pushed. The detection system software controlling data collection has components that facilitate completing a grid-less survey on user specified spacings. Another package confirms that all data quality activities (calibrations, etc.) are conducted prior to beginning the survey and also reviews data to identify areas that have been missed for which data quality falls below user designated parameters. Advanced digital signal processing algorithms are used to enhance the interpretation of spectra for conducting background subtractions and for mapping. Data from radiation detection instruments and GPS antennae are merged and made compatible with mapping using Geosoft Oasis montaj software. A summary of system performance during field-testing is included in the paper. This includes survey rate, detection limits, duty cycle, supporting ancillary equipment/material, and manpower requirements. The rate of false positives and false negatives is discussed with the benefits of surveys conducted using synergetic detection systems such as electromagnetic induction imaging. (authors)

An advanced complex analysis problem book topological vector spaces, functional analysis, and Hilbert spaces of analytic functions

CERN Document Server

Alpay, Daniel

2015-01-01

This is an exercises book at the beginning graduate level, whose aim is to illustrate some of the connections between functional analysis and the theory of functions of one variable. A key role is played by the notions of positive definite kernel and of reproducing kernel Hilbert space. A number of facts from functional analysis and topological vector spaces are surveyed. Then, various Hilbert spaces of analytic functions are studied.

Bias-limited extraction of cosmological parameters

Energy Technology Data Exchange (ETDEWEB)

Shimon, Meir; Itzhaki, Nissan; Rephaeli, Yoel, E-mail: meirs@wise.tau.ac.il, E-mail: nitzhaki@post.tau.ac.il, E-mail: yoelr@wise.tau.ac.il [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

2013-03-01

It is known that modeling uncertainties and astrophysical foregrounds can potentially introduce appreciable bias in the deduced values of cosmological parameters. While it is commonly assumed that these uncertainties will be accounted for to a sufficient level of precision, the level of bias has not been properly quantified in most cases of interest. We show that the requirement that the bias in derived values of cosmological parameters does not surpass nominal statistical error, translates into a maximal level of overall error O(N{sup −½}) on |ΔP(k)|/P(k) and |ΔC{sub l}|/C{sub l}, where P(k), C{sub l}, and N are the matter power spectrum, angular power spectrum, and number of (independent Fourier) modes at a given scale l or k probed by the cosmological survey, respectively. This required level has important consequences on the precision with which cosmological parameters are hoped to be determined by future surveys: in virtually all ongoing and near future surveys N typically falls in the range 10{sup 6}−10{sup 9}, implying that the required overall theoretical modeling and numerical precision is already very high. Future redshifted-21-cm observations, projected to sample ∼ 10{sup 14} modes, will require knowledge of the matter power spectrum to a fantastic 10{sup −7} precision level. We conclude that realizing the expected potential of future cosmological surveys, which aim at detecting 10{sup 6}−10{sup 14} modes, sets the formidable challenge of reducing the overall level of uncertainty to 10{sup −3}−10{sup −7}.

Cosmology with cluster surveys

Indian Academy of Sciences (India)

Abstract. Surveys of clusters of galaxies provide us with a powerful probe of the den- sity and nature of the dark energy. The red-shift distribution of detected clusters is highly sensitive to the dark energy equation of state parameter w. Upcoming Sunyaev–. Zel'dovich (SZ) surveys would provide us large yields of clusters to ...

Tracing The Sound Horizon Scale With Photometric Redshift Surveys

CERN Document Server

Sanchez, E; Garcia-Bellido, J; Gaztanaga, E; de Simoni, F; Crocce, M; Cabre, A; Fosalba, P; Alonso, D

2010-01-01

We propose a new method for cosmological parameters extraction using the baryon acoustic oscillation scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical parametric fit to the angular 2-point correlation function w(theta). It is parametrized as a power law to describe the continuum plus a Gaussian to describe the BAO bump. The location of the Gaussian is used as the basis for the measurement of the sound horizon scale. This method, although simple, actually provides a robust estimation, since the inclusion of the power law and the use of the Gaussian removes the shifts which affect the local maximum. We discuss the effects of projection bias, non-linearities, redshift space distortions and photo-z precision, and apply our method to a mock catalog of the Dark Energy Survey, built upon a large N-body simulation provided by the MICE collaboration. We discuss the main systematic errors associated to our method and show that they ar...

Biomedical engineering strategies in system design space.

Science.gov (United States)

Savageau, Michael A

2011-04-01

Modern systems biology and synthetic bioengineering face two major challenges in relating properties of the genetic components of a natural or engineered system to its integrated behavior. The first is the fundamental unsolved problem of relating the digital representation of the genotype to the analog representation of the parameters for the molecular components. For example, knowing the DNA sequence does not allow one to determine the kinetic parameters of an enzyme. The second is the fundamental unsolved problem of relating the parameters of the components and the environment to the phenotype of the global system. For example, knowing the parameters does not tell one how many qualitatively distinct phenotypes are in the organism's repertoire or the relative fitness of the phenotypes in different environments. These also are challenges for biomedical engineers as they attempt to develop therapeutic strategies to treat pathology or to redirect normal cellular functions for biotechnological purposes. In this article, the second of these fundamental challenges will be addressed, and the notion of a "system design space" for relating the parameter space of components to the phenotype space of bioengineering systems will be focused upon. First, the concept of a system design space will be motivated by introducing one of its key components from an intuitive perspective. Second, a simple linear example will be used to illustrate a generic method for constructing the design space in which qualitatively distinct phenotypes can be identified and counted, their fitness analyzed and compared, and their tolerance to change measured. Third, two examples of nonlinear systems from different areas of biomedical engineering will be presented. Finally, after giving reference to a few other applications that have made use of the system design space approach to reveal important design principles, some concluding remarks concerning challenges and opportunities for further development

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

Science.gov (United States)

Quiroga-Nuñez, L. H.; van Langevelde, H. J.; Reid, M. J.; Green, J. A.

2017-08-01

Context. Using trigonometric parallaxes and proper motions of masers associated with massive young stars, the Bar and Spiral Structure Legacy (BeSSeL) survey has reported the most accurate values of the Galactic parameters so far. The determination of these parameters with high accuracy has a widespread impact on Galactic and extragalactic measurements. Aims: This research is aimed at establishing the confidence with which such parameters can be determined. This is relevant for the data published in the context of the BeSSeL survey collaboration, but also for future observations, in particular from the southern hemisphere. In addition, some astrophysical properties of the masers can be constrained, notably the luminosity function. Methods: We have simulated the population of maser-bearing young stars associated with Galactic spiral structure, generating several samples and comparing them with the observed samples used in the BeSSeL survey. Consequently, we checked the determination of Galactic parameters for observational biases introduced by the sample selection. Results: Galactic parameters obtained by the BeSSeL survey do not seem to be biased by the sample selection used. In fact, the published error estimates appear to be conservative for most of the parameters. We show that future BeSSeL data and future observations with southern arrays will improve the Galactic parameters estimates and smoothly reduce their mutual correlation. Moreover, by modeling future parallax data with larger distance values and, thus, greater relative uncertainties for a larger numbers of sources, we found that parallax-distance biasing is an important issue. Hence, using fractional parallax uncertainty in the weighting of the motion data is imperative. Finally, the luminosity function for 6.7 GHz methanol masers was determined, allowing us to estimate the number of Galactic methanol masers.

Distance to green space and physical activity: a danish national representative survey

DEFF Research Database (Denmark)

Toftager, Mette; Ekholm, Ola; Schipperijn, Jasper

2011-01-01

This study examines the relationship between distance to green space and the level of physical activity among the population of Denmark. In addition, the relationship between distance to green space and obesity is investigated.......This study examines the relationship between distance to green space and the level of physical activity among the population of Denmark. In addition, the relationship between distance to green space and obesity is investigated....

WHITE DWARF-RED DWARF SYSTEMS RESOLVED WITH THE HUBBLE SPACE TELESCOPE. II. FULL SNAPSHOT SURVEY RESULTS

International Nuclear Information System (INIS)

Farihi, J.; Hoard, D. W.; Wachter, S.

2010-01-01

Results are presented for a Hubble Space Telescope Advanced Camera for Surveys high-resolution imaging campaign of 90 white dwarfs with known or suspected low-mass stellar and substellar companions. Of the 72 targets that remain candidate and confirmed white dwarfs with near-infrared excess, 43 are spatially resolved into two or more components, and a total of 12 systems are potentially triples. For 68 systems where a comparison is possible, 50% have significant photometric distance mismatches between their white dwarf and M dwarf components, suggesting that white dwarf parameters derived spectroscopically are often biased due to the cool companion. Interestingly, 9 of the 30 binaries known to have emission lines are found to be visual pairs and hence widely separated, indicating an intrinsically active cool star and not irradiation from the white dwarf. There is a possible, slight deficit of earlier spectral types (bluer colors) among the spatially unresolved companions, exactly the opposite of expectations if significant mass is transferred to the companion during the common envelope phase. Using the best available distance estimates, the low-mass companions to white dwarfs exhibit a bimodal distribution in projected separation. This result supports the hypothesis that during the giant phases of the white dwarf progenitor, any unevolved companions either migrate inward to short periods of hours to days, or outward to periods of hundreds to thousands of years. No intermediate projected separations of a few to several AU are found among these pairs. However, a few double M dwarfs (within triples) are spatially resolved in this range, empirically demonstrating that such separations were readily detectable among the binaries with white dwarfs. A straightforward and testable prediction emerges: all spatially unresolved, low-mass stellar and substellar companions to white dwarfs should be in short-period orbits. This result has implications for substellar companion and

Quantum space and quantum completeness

Science.gov (United States)

Jurić, Tajron

2018-05-01

Motivated by the question whether quantum gravity can "smear out" the classical singularity we analyze a certain quantum space and its quantum-mechanical completeness. Classical singularity is understood as a geodesic incompleteness, while quantum completeness requires a unique unitary time evolution for test fields propagating on an underlying background. Here the crucial point is that quantum completeness renders the Hamiltonian (or spatial part of the wave operator) to be essentially self-adjoint in order to generate a unique time evolution. We examine a model of quantum space which consists of a noncommutative BTZ black hole probed by a test scalar field. We show that the quantum gravity (noncommutative) effect is to enlarge the domain of BTZ parameters for which the relevant wave operator is essentially self-adjoint. This means that the corresponding quantum space is quantum complete for a larger range of BTZ parameters rendering the conclusion that in the quantum space one observes the effect of "smearing out" the singularity.

Parameter Uncertainty for Repository Thermal Analysis

Energy Technology Data Exchange (ETDEWEB)

Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Greenberg, Harris [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dupont, Mark [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-10-01

This report is one follow-on to a study of reference geologic disposal design concepts (Hardin et al. 2011a). Based on an analysis of maximum temperatures, that study concluded that certain disposal concepts would require extended decay storage prior to emplacement, or the use of small waste packages, or both. The study used nominal values for thermal properties of host geologic media and engineered materials, demonstrating the need for uncertainty analysis to support the conclusions. This report is a first step that identifies the input parameters of the maximum temperature calculation, surveys published data on measured values, uses an analytical approach to determine which parameters are most important, and performs an example sensitivity analysis. Using results from this first step, temperature calculations planned for FY12 can focus on only the important parameters, and can use the uncertainty ranges reported here. The survey of published information on thermal properties of geologic media and engineered materials, is intended to be sufficient for use in generic calculations to evaluate the feasibility of reference disposal concepts. A full compendium of literature data is beyond the scope of this report. The term “uncertainty” is used here to represent both measurement uncertainty and spatial variability, or variability across host geologic units. For the most important parameters (e.g., buffer thermal conductivity) the extent of literature data surveyed samples these different forms of uncertainty and variability. Finally, this report is intended to be one chapter or section of a larger FY12 deliverable summarizing all the work on design concepts and thermal load management for geologic disposal (M3FT-12SN0804032, due 15Aug2012).

Pump Component Model in SPACE Code

International Nuclear Information System (INIS)

Kim, Byoung Jae; Kim, Kyoung Doo

2010-08-01

This technical report describes the pump component model in SPACE code. A literature survey was made on pump models in existing system codes. The models embedded in SPACE code were examined to check the confliction with intellectual proprietary rights. Design specifications, computer coding implementation, and test results are included in this report

Incorporating space charge in the transverse phase-space matching and tomography at PITZ

Energy Technology Data Exchange (ETDEWEB)

Kourkafas, Georgios

2015-11-15

The ever-expanding achievements in the field of particle accelerators push their specifications to very demanding levels. The performance of many modern applications depends on their ability to be operated with high bunch charges confined in small volumes. However, the consequence of increased intensity is strong space-charge forces, which perplex the beam manipulation and undermine the beam quality. As a result, reliable methods are needed to control and measure the accelerated particles under these extraordinary conditions. The phase space tomography is a diagnostic technique which can reveal details of the transverse beam parameters for a wide range of intensities and energies, with minimal influence from the machine instabilities, in a quasi non-destructive way. The accuracy of this method relies on the precise knowledge and control of the particle dynamics under the influence of space charge in different stages of the measurement. On the one hand, the matching of the beam to the measurement's design transverse parameters requires a procedure which efficiently compensates the effects of space charge. Depending on the structure of the magnetic lattice, different aspects of these effects prevail, therefore different strategies have to be developed. On the other hand, the impact of the space-charge forces on the phase-space transformations during the data acquisition has to be included in the model which is used for the tomographic reconstruction. The aim of this thesis is to provide and test time-efficient solutions for the incorporation of space charge in the transverse beam matching and phase space tomography.

Incorporating space charge in the transverse phase-space matching and tomography at PITZ

International Nuclear Information System (INIS)

Kourkafas, Georgios

2015-11-01

The ever-expanding achievements in the field of particle accelerators push their specifications to very demanding levels. The performance of many modern applications depends on their ability to be operated with high bunch charges confined in small volumes. However, the consequence of increased intensity is strong space-charge forces, which perplex the beam manipulation and undermine the beam quality. As a result, reliable methods are needed to control and measure the accelerated particles under these extraordinary conditions. The phase space tomography is a diagnostic technique which can reveal details of the transverse beam parameters for a wide range of intensities and energies, with minimal influence from the machine instabilities, in a quasi non-destructive way. The accuracy of this method relies on the precise knowledge and control of the particle dynamics under the influence of space charge in different stages of the measurement. On the one hand, the matching of the beam to the measurement's design transverse parameters requires a procedure which efficiently compensates the effects of space charge. Depending on the structure of the magnetic lattice, different aspects of these effects prevail, therefore different strategies have to be developed. On the other hand, the impact of the space-charge forces on the phase-space transformations during the data acquisition has to be included in the model which is used for the tomographic reconstruction. The aim of this thesis is to provide and test time-efficient solutions for the incorporation of space charge in the transverse beam matching and phase space tomography.

On the breakdown modes and parameter space of Ohmic Tokamak startup

Science.gov (United States)

Peng, Yanli; Jiang, Wei; Zhang, Ya; Hu, Xiwei; Zhuang, Ge; Innocenti, Maria; Lapenta, Giovanni

2017-10-01

Tokamak plasma has to be hot. The process of turning the initial dilute neutral hydrogen gas at room temperature into fully ionized plasma is called tokamak startup. Even with over 40 years of research, the parameter ranges for the successful startup still aren't determined by numerical simulations but by trial and errors. However, in recent years it has drawn much attention due to one of the challenges faced by ITER: the maximum electric field for startup can't exceed 0.3 V/m, which makes the parameter range for successful startup narrower. Besides, this physical mechanism is far from being understood either theoretically or numerically. In this work, we have simulated the plasma breakdown phase driven by pure Ohmic heating using a particle-in-cell/Monte Carlo code, with the aim of giving a predictive parameter range for most tokamaks, even for ITER. We have found three situations during the discharge, as a function of the initial parameters: no breakdown, breakdown and runaway. Moreover, breakdown delay and volt-second consumption under different initial conditions are evaluated. In addition, we have simulated breakdown on ITER and confirmed that when the electric field is 0.3 V/m, the optimal pre-filling pressure is 0.001 Pa, which is in good agreement with ITER's design.

Learning space preferences of higher education students

NARCIS (Netherlands)

Beckers, R.; van der Voordt, Theo; Dewulf, G

2016-01-01

This paper aims to address higher education students' learning space preferences. The study is based on a survey that involved 697 business management students of a Dutch University of Applied Sciences. The research focuses on preferred learning spaces for individual study activities, which

Learning space preferences of higher education students

NARCIS (Netherlands)

Beckers, Ronald; van der Voordt, Theo; Dewulf, Geert P.M.R.

2016-01-01

This paper aims to address higher education students’ learning space preferences. The study is based on a survey that involved 697 business management students of a Dutch University of Applied Sciences. The research focuses on preferred learning spaces for individual study activities, which require

DEEBAR - A BASIC interactive computer programme for estimating mean resonance spacings

International Nuclear Information System (INIS)

Booth, M.; Pope, A.L.; Smith, R.W.; Story, J.S.

1988-02-01

DEEBAR is a BASIC interactive programme, which uses the theories of Dyson and of Dyson and Mehta, to compute estimates of the mean resonance spacings and associated uncertainty statistics from an input file of neutron resonance energies. In applying these theories the broad scale energy dependence of D-bar, as predicted by the ordinary theory of level densities, is taken into account. The mean spacing D-bar ± δD-bar, referred to zero energy of the incident neutrons, is computed from the energies of the first k resonances, for k = 2,3...K in turn and as if no resonances are missing. The user is asked to survey this set of D-bar and δD-bar values and to form a judgement - up to what value of k is the set of resonances complete and what value, in consequence, does the user adopt as the preferred value of D-bar? When the preferred values for k and D-bar have been input, the programme calculates revised values for the level density parameters, consistent with this value for D-bar and with other input information. Two short tables are printed, illustrating the energy variation and spin dependence of D-bar. Dyson's formula based on his Coulomb gas analogy is used for estimating the most likely energies of the topmost bound levels. Finally the quasi-crystalline character of a single level series is exploited by means of a table in which the resonance energies are set alongside an energy ladder whose rungs are regularly spaced with spacing D-bar(E); this comparative table expedites the search for gaps where resonances may have been missed experimentally. Used in conjunction with the program LJPROB, which calculates neutron strengths and compares them against the expected Porter Thomas distribution, estimates of the statistical parameters for use in the unresolved resonance region may be derived. (author)

Kuranishi spaces as a 2-category

OpenAIRE

Joyce, Dominic

2015-01-01

This is a survey of the author's in-progress book arXiv:1409.6908. 'Kuranishi spaces' were introduced in the work of Fukaya, Oh, Ohta and Ono in symplectic geometry (see e.g. arXiv:1503.07631), as the geometric structure on moduli spaces of $J$-holomorphic curves. We propose a new definition of Kuranishi space, which has the nice property that they form a 2-category $\\bf Kur$. Thus the homotopy category Ho$({\\bf Kur})$ is an ordinary category of Kuranishi spaces. Any Fukaya-Oh-Ohta-Ono (FOOO)...

Solid state semiconductor detectorized survey meter

International Nuclear Information System (INIS)

Okamoto, Eisuke; Nagase, Yoshiyuki; Furuhashi, Masato

1987-01-01

Survey meters are used for measurement of gamma ray dose rate of the space and the surface contamination dencity that the atomic energy plant and the radiation facility etc. We have recently developed semiconductor type survey meter (Commercial name: Compact Survey Meter). This survey meter is a small-sized dose rate meter with excellent function. The special features are using semiconductor type detector which we have developed by our own technique, stablar wide range than the old type, long life, and easy to carry. Now we introduce the efficiency and the function of the survey meter. (author)

Green space as classroom

DEFF Research Database (Denmark)

Bentsen, Peter; Schipperijn, Jasper; Jensen, Frank Søndergaard

2013-01-01

More and more Danish teachers have started introducing curriculum-based outdoor learning as a weekly or biweekly ‘outdoor school’ day for school children. This move towards schooling in non-classroom spaces presents a challenge for green space managers. Basic managerial knowledge related to what......, who, when and where has thus far only been supported by anecdotal evidence, but seems fundamental to the decision-making of a range of green space providers. The present study aims to describe, characterise and discuss outdoor teachers’ use, preferences and ecostrategies in relation to green space....... A nationwide survey was conducted among Danish teachers practising outdoor teaching (107 respondents), and it showed that a majority used and preferred forest areas. The outdoor teachers used mainly school grounds and local green space for their outdoor teaching with a majority using the same place or mostly...

Survey < > Creation

DEFF Research Database (Denmark)

2017-01-01

The project, Survey Creation suggests that point cloud models from 3D scans of an existing space can be the source for explorative drawings. By probing into the procedure of 3D laser scanning, it became possible to make use of the available point clouds to both access geometric representation......) and the creation drawing (of the anticipated)....

Galaxy redshift surveys with sparse sampling

International Nuclear Information System (INIS)

Chiang, Chi-Ting; Wullstein, Philipp; Komatsu, Eiichiro; Jee, Inh; Jeong, Donghui; Blanc, Guillermo A.; Ciardullo, Robin; Gronwall, Caryl; Hagen, Alex; Schneider, Donald P.; Drory, Niv; Fabricius, Maximilian; Landriau, Martin; Finkelstein, Steven; Jogee, Shardha; Cooper, Erin Mentuch; Tuttle, Sarah; Gebhardt, Karl; Hill, Gary J.

2013-01-01

Survey observations of the three-dimensional locations of galaxies are a powerful approach to measure the distribution of matter in the universe, which can be used to learn about the nature of dark energy, physics of inflation, neutrino masses, etc. A competitive survey, however, requires a large volume (e.g., V survey ∼ 10Gpc 3 ) to be covered, and thus tends to be expensive. A ''sparse sampling'' method offers a more affordable solution to this problem: within a survey footprint covering a given survey volume, V survey , we observe only a fraction of the volume. The distribution of observed regions should be chosen such that their separation is smaller than the length scale corresponding to the wavenumber of interest. Then one can recover the power spectrum of galaxies with precision expected for a survey covering a volume of V survey (rather than the volume of the sum of observed regions) with the number density of galaxies given by the total number of observed galaxies divided by V survey (rather than the number density of galaxies within an observed region). We find that regularly-spaced sampling yields an unbiased power spectrum with no window function effect, and deviations from regularly-spaced sampling, which are unavoidable in realistic surveys, introduce calculable window function effects and increase the uncertainties of the recovered power spectrum. On the other hand, we show that the two-point correlation function (pair counting) is not affected by sparse sampling. While we discuss the sparse sampling method within the context of the forthcoming Hobby-Eberly Telescope Dark Energy Experiment, the method is general and can be applied to other galaxy surveys

Pinching parameters for open (super) strings

Science.gov (United States)

Playle, Sam; Sciuto, Stefano

2018-02-01

We present an approach to the parametrization of (super) Schottky space obtained by sewing together three-punctured discs with strips. Different cubic ribbon graphs classify distinct sets of pinching parameters; we show how they are mapped onto each other. The parametrization is particularly well-suited to describing the region within (super) moduli space where open bosonic or Neveu-Schwarz string propagators become very long and thin, which dominates the IR behaviour of string theories. We show how worldsheet objects such as the Green's function converge to graph theoretic objects such as the Symanzik polynomials in the α ' → 0 limit, allowing us to see how string theory reproduces the sum over Feynman graphs. The (super) string measure takes on a simple and elegant form when expressed in terms of these parameters.

Biomimetics on seed dispersal: survey and insights for space exploration

International Nuclear Information System (INIS)

Pandolfi, Camilla; Izzo, Dario

2013-01-01

Seeds provide the vital genetic link and dispersal agent between successive generations of plants. Without seed dispersal as a means of reproduction, many plants would quickly die out. Because plants lack any sort of mobility and remain in the same spot for their entire lives, they rely on seed dispersal to transport their offspring throughout the environment. This can be accomplished either collectively or individually; in any case as seeds ultimately abdicate their movement, they are at the mercy of environmental factors. Thus, seed dispersal strategies are characterized by robustness, adaptability, intelligence (both behavioral and morphological), and mass and energy efficiency (including the ability to utilize environmental sources of energy available): all qualities that advanced engineering systems aim at in general, and in particular those that need to enable complex endeavors such as space exploration. Plants evolved and adapted their strategy according to their environment, and taken together, they enclose many desirable characteristics that a space mission needs to have. Understanding in detail how plants control the development of seeds, fabricate structural components for their dispersal, build molecular machineries to keep seeds dormant up to the right moment and monitor the environment to release them at the right time could provide several solutions impacting current space mission design practices. It can lead to miniaturization, higher integration and packing efficiency, energy efficiency and higher autonomy and robustness. Consequently, there would appear to be good reasons for considering biomimetic solutions from plant kingdom when designing space missions, especially to other celestial bodies, where solid and liquid surfaces, atmosphere, etc constitute and are obviously parallel with the terrestrial environment where plants evolved. In this paper, we review the current state of biomimetics on seed dispersal to improve space mission design

Generalized Lions-Peetre interpolation construction and optimal embedding theorems for Sobolev spaces

International Nuclear Information System (INIS)

Ovchinnikov, V I

2014-01-01

In the paper, a new description of the generalized Lions-Peetre method of means is found, which enables one to evaluate the interpolation orbits of spaces constructed by this method. The list of these spaces includes all Lorentz spaces with functional parameters, Orlicz spaces, and spaces close to them. This leads in turn to new optimal embedding theorems for Sobolev spaces produced using the Lions-Peetre construction in rearrangement invariant spaces. It turns out that the optimal space of the embedding is also a generalized Lions-Peetre space whose parameters are explicitly evaluated. Bibliography: 18 titles

The parameter spreadsheets and their applications

International Nuclear Information System (INIS)

Schwitters, R.; Chao, A.; Chou, W.; Peterson, J.

1993-01-01

This paper is to announce that a set of parameter spreadsheets, using the Microsoft EXCEL software, has been developed for the SSC (and also for the LHC). In this program, the input (or control) parameters and the derived parameters are linked by equations that express the accelerator physics involved. A subgroup of parameters that are considered critical, or possible bottlenecks, has been highlighted under the category of open-quotes Flagsclose quotes. Given certain performance goals, one can use this program to open-quotes tuneclose quotes the input parameters in such a way that the flagged parameters do not exceed their acceptable range. During the past years, this program has been employed for the following purposes: (a) To guide the machine designs for various operation scenarios, (b) To generate a parameter list that is self-consistent and, (c) To study the impact of some proposed parameter changes (e.g., different choices of the rf frequency and bunch spacing)

The GALAH survey

DEFF Research Database (Denmark)

Kos, Janez; Bland-Hawthor, Joss; Freeman, Ken

2018-01-01

-SNE) - which identifies an optimal mapping of a high-dimensional space into fewer dimensions - whilst conserving the original clustering information. Typically, the projection is made to a 2D space to aid recognition of clusters by eye. We show that this method is a reliable tool for chemical tagging because......The technique of chemical tagging uses the elemental abundances of stellar atmospheres to 'reconstruct' chemically homogeneous star clusters that have long since dispersed. The GALAH spectroscopic survey - which aims to observe one million stars using the Anglo-Australian Telescope - allows us...... to measure up to 30 elements or dimensions in the stellar chemical abundance space, many of which are not independent. How to find clustering reliably in a noisy high-dimensional space is a difficult problem that remains largely unsolved. Here, we explore t-distributed stochastic neighbour embedding (t...

Preparing for the WFIRST Microlensing Survey: Simulations, Requirements, Survey Strategies, and Precursor Observations

Science.gov (United States)

Gaudi, Bernard

As one of the four primary investigations of the Wide Field Infrared Survey Telescope (WFIRST) mission, the microlensing survey will monitor several square degrees of the Galactic bulge for a total of roughly one year. Its primary science goal is to "Complete the statistical census of planetary systems in the Galaxy, from the outer habitable zone to free floating planets, including analogs of all of the planets in our Solar System with the mass of Mars or greater.'' WFIRST will therefore (a) measure the mass function of cold bound planets with masses greater than that of roughly twice the mass of the moon, including providing an estimate of the frequency of sub-Mars-mass embryos, (b) determine the frequency of free-floating planets with masses down to the Earth and below, (c) inform the frequency and habitability of potentially habitable worlds, and (d) revolutionize our understanding of the demographics of cold planets with its exquisite sensitivity to, and large expected yield of, planets in a broad and unexplored region of parameter space. In order for the microlensing survey to be successful, we must develop a plan to go from actual survey observations obtained by the WFIRST telescope and hardware to the final science products. This plan will involve many steps, the development of software, data reduction, and analysis tools at each step, and a list of requirements for each of these components. The overarching goal of this proposal is thus to develop a complete flowdown from the science goals of the microlensing survey to the mission design and hardware components. We have assembled a team of scientists with the breadth of expertise to achieve this primary goal. Our specific subgoals are as follows. Goal 1: We will refine the input Galactic models in order to provide improved microlensing event rates in the WFIRST fields. Goal 2: We will use the improved event rate estimates, along with improvements in our simulation methodology, to provide higher

The Value Of Enhanced Neo Surveys

Science.gov (United States)

Harris, Alan W.

2012-10-01

NEO surveys have now achieved, more or less, the “Spaceguard Goal” of cataloging 90% of NEAs larger than 1 km in diameter, and thereby have reduced the short-term hazard from cosmic impacts by about an order of magnitude, from an actuarial estimate of 1,000 deaths per year (actually about a billion every million years, with very little in between), to about 100 deaths per year, with a shift toward smaller but more frequent events accounting for the remaining risk. It is fair to ask, then, what is the value of a next-generation accelerated survey to “retire” much of the remaining risk. The curve of completion of survey versus size of NEA is remarkably similar for any survey, ground or space based, visible light or thermal IR, so it is possible to integrate risk over all sizes, with a time variable curve of completion to evaluate the actuarial value of speeding up survey completion. I will present my latest estimate of NEA population and completion of surveys. From those I will estimate the “value” of accelerated surveys such as Pan-STARRS, LSST, or space-based surveys, versus continuing with current surveys. My tentative conclusion is that we may have already reached the point in terms of cost-benefit where accelerated surveys are not cost-effective in terms of reducing impact risk. If not yet, we soon will. On the other hand, the surveys, which find and catalog main-belt and other classes of small bodies as well as NEOs, have provided a gold mine of good science. The scientific value of continued or accelerated surveys needs to be emphasized as the impact risk is increasingly “retired.”

Meteor Shower Forecast Improvements from a Survey of All-Sky Network Observations

Science.gov (United States)

Moorhead, Althea V.; Sugar, Glenn; Brown, Peter G.; Cooke, William J.

2015-01-01

Meteoroid impacts are capable of damaging spacecraft and potentially ending missions. In order to help spacecraft programs mitigate these risks, NASA's Meteoroid Environment Office (MEO) monitors and predicts meteoroid activity. Temporal variations in near-Earth space are described by the MEO's annual meteor shower forecast, which is based on both past shower activity and model predictions. The MEO and the University of Western Ontario operate sister networks of all-sky meteor cameras. These networks have been in operation for more than 7 years and have computed more than 20,000 meteor orbits. Using these data, we conduct a survey of meteor shower activity in the "fireball" size regime using DBSCAN. For each shower detected in our survey, we compute the date of peak activity and characterize the growth and decay of the shower's activity before and after the peak. These parameters are then incorporated into the annual forecast for an improved treatment of annual activity.

Space Industry Commercialization: A Systems Engineering Evaluation of Alternatives

Science.gov (United States)

Dinally, Jihan

The Constellation Program cancellation reversed the government and commercial space industry's roles and relationships by dedicating the majority of the federal funding and opportunities to the commercial space industry and left the government space industry in search of an approach to collaborate with the dominant organization, the commercial space industry service providers. The space industry government agencies, Air Force Space Command (AFSPC) and National Aeronautics and Space Administration (NASA) had realized that to gain resources in the new commercially oriented economic environment, they had to work together and possess the capabilities aligned with the National Space Policy's documented goals. Multi-organizational collaboration in space industry programs is challenging, as NASA, AFSPC, and commercial providers, follow different [1] enterprise architecture guidance such as the NASA systems engineering Handbook, MIL-STD-499 and "A Guide to the systems engineering Body of Knowledge" by the International Council on systems engineering [2] [3]. A solution to streamline their enterprise architecture documentation and meet National Space Policy goals is the Multi-User Architecture Maturity Model Methodology (MAM3), which offers a tailored systems engineering technique the government agencies and private companies can implement for the program's maturity level. In order to demonstrate the MAM3, a CubeSat motivated study was conducted partnering a commercial provider with a government agency. A survey of the commercial space industry service providers' capabilities was performed to select the private companies for the study. Using the survey results, the commercial space industry service providers were ranked using the Analytic Hierarchy Process (AHP) [4]. The AHP is a structured technique for making complex decisions for representing and quantifying its weights, relating those weights to overall goals, and evaluating alternative solutions [5] - [8]. The weights

A Solution to Modeling Multilevel Confirmatory Factor Analysis with Data Obtained from Complex Survey Sampling to Avoid Conflated Parameter Estimates

Directory of Open Access Journals (Sweden)

Jiun-Yu Wu

2017-09-01

Full Text Available The issue of equality in the between-and within-level structures in Multilevel Confirmatory Factor Analysis (MCFA models has been influential for obtaining unbiased parameter estimates and statistical inferences. A commonly seen condition is the inequality of factor loadings under equal level-varying structures. With mathematical investigation and Monte Carlo simulation, this study compared the robustness of five statistical models including two model-based (a true and a mis-specified models, one design-based, and two maximum models (two models where the full rank of variance-covariance matrix is estimated in between level and within level, respectively in analyzing complex survey measurement data with level-varying factor loadings. The empirical data of 120 3rd graders' (from 40 classrooms perceived Harter competence scale were modeled using MCFA and the parameter estimates were used as true parameters to perform the Monte Carlo simulation study. Results showed maximum models was robust to unequal factor loadings while the design-based and the miss-specified model-based approaches produced conflated results and spurious statistical inferences. We recommend the use of maximum models if researchers have limited information about the pattern of factor loadings and measurement structures. Measurement models are key components of Structural Equation Modeling (SEM; therefore, the findings can be generalized to multilevel SEM and CFA models. Mplus codes are provided for maximum models and other analytical models.

Spaces of positive and negative frequency solutions of field equations in curved space--times. I. The Klein--Gordon equation in stationary space--times

International Nuclear Information System (INIS)

Moreno, C.

1977-01-01

In stationary space--times V/sub n/ x R with compact space-section manifold without boundary V/sub n/, the Klein--Gordon equation is solved by the one-parameter group of unitary operators generated by the energy operator i -1 T -1 in the Sobolev spaces H/sup l/(V/sub n/) x H/sup l/(V/sub n/). The canonical symplectic and complex structures of the associated dynamical system are calculated. The existence and the uniqueness of the Lichnerowicz kernel are established. The Hilbert spaces of positive and negative frequency-part solutions defined by means of this kernel are constructed

Influence of simulation assumptions and input parameters on energy balance calculations of residential buildings

International Nuclear Information System (INIS)

Dodoo, Ambrose; Tettey, Uniben Yao Ayikoe; Gustavsson, Leif

2017-01-01

In this study, we modelled the influence of different simulation assumptions on energy balances of two variants of a residential building, comprising the building in its existing state and with energy-efficient improvements. We explored how selected parameter combinations and variations affect the energy balances of the building configurations. The selected parameters encompass outdoor microclimate, building thermal envelope and household electrical equipment including technical installations. Our modelling takes into account hourly as well as seasonal profiles of different internal heat gains. The results suggest that the impact of parameter interactions on calculated space heating of buildings is somewhat small and relatively more noticeable for an energy-efficient building in contrast to a conventional building. We find that the influence of parameters combinations is more apparent as more individual parameters are varied. The simulations show that a building's calculated space heating demand is significantly influenced by how heat gains from electrical equipment are modelled. For the analyzed building versions, calculated final energy for space heating differs by 9–14 kWh/m"2 depending on the assumed energy efficiency level for electrical equipment. The influence of electrical equipment on calculated final space heating is proportionally more significant for an energy-efficient building compared to a conventional building. This study shows the influence of different simulation assumptions and parameter combinations when varied simultaneously. - Highlights: • Energy balances are modelled for conventional and efficient variants of a building. • Influence of assumptions and parameter combinations and variations are explored. • Parameter interactions influence is apparent as more single parameters are varied. • Calculated space heating demand is notably affected by how heat gains are modelled.

Y-STR frequency surveying method

DEFF Research Database (Denmark)

Willuweit, Sascha; Caliebe, Amke; Andersen, Mikkel Meyer

2011-01-01

Reasonable formalized methods to estimate the frequencies of DNA profiles generated from lineage markers have been proposed in the past years and were discussed in the forensic community. Recently, collections of population data on the frequencies of variations in Y chromosomal STR profiles have...... reached a new quality with the establishment of the comprehensive neatly quality-controlled reference database YHRD. Grounded on such unrivalled empirical material from hundreds of populations studies the core assumption of the Haplotype Frequency Surveying Method originally described 10 years ago can...... be tested and improved. Here we provide new approaches to calculate the parameters used in the frequency surveying method: a maximum likelihood estimation of the regression parameters (r1, r2, s1 and s2) and a revised Frequency Surveying framework with variable binning and a database preprocessing to take...

A probabilistic approach for the estimation of earthquake source parameters from spectral inversion

Science.gov (United States)

Supino, M.; Festa, G.; Zollo, A.

2017-12-01

The amplitude spectrum of a seismic signal related to an earthquake source carries information about the size of the rupture, moment, stress and energy release. Furthermore, it can be used to characterize the Green's function of the medium crossed by the seismic waves. We describe the earthquake amplitude spectrum assuming a generalized Brune's (1970) source model, and direct P- and S-waves propagating in a layered velocity model, characterized by a frequency-independent Q attenuation factor. The observed displacement spectrum depends indeed on three source parameters, the seismic moment (through the low-frequency spectral level), the corner frequency (that is a proxy of the fault length) and the high-frequency decay parameter. These parameters are strongly correlated each other and with the quality factor Q; a rigorous estimation of the associated uncertainties and parameter resolution is thus needed to obtain reliable estimations.In this work, the uncertainties are characterized adopting a probabilistic approach for the parameter estimation. Assuming an L2-norm based misfit function, we perform a global exploration of the parameter space to find the absolute minimum of the cost function and then we explore the cost-function associated joint a-posteriori probability density function around such a minimum, to extract the correlation matrix of the parameters. The global exploration relies on building a Markov chain in the parameter space and on combining a deterministic minimization with a random exploration of the space (basin-hopping technique). The joint pdf is built from the misfit function using the maximum likelihood principle and assuming a Gaussian-like distribution of the parameters. It is then computed on a grid centered at the global minimum of the cost-function. The numerical integration of the pdf finally provides mean, variance and correlation matrix associated with the set of best-fit parameters describing the model. Synthetic tests are performed to

Weak lensing Study in VOICE Survey I: Shear Measurement

Science.gov (United States)

Fu, Liping; Liu, Dezi; Radovich, Mario; Liu, Xiangkun; Pan, Chuzhong; Fan, Zuhui; Covone, Giovanni; Vaccari, Mattia; Amaro, Valeria; Brescia, Massimo; Capaccioli, Massimo; De Cicco, Demetra; Grado, Aniello; Limatola, Luca; Miller, Lance; Napolitano, Nicola R.; Paolillo, Maurizio; Pignata, Giuliano

2018-06-01

The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is a Guaranteed Time program carried out with the ESO/VST telescope to provide deep optical imaging over two 4 deg2 patches of the sky centred on the CDFS and ES1 pointings. We present the cosmic shear measurement over the 4 deg2 covering the CDFS region in the r-band using LensFit. Each of the four tiles of 1 deg2 has more than one hundred exposures, of which more than 50 exposures passed a series of image quality selection criteria for weak lensing study. The 5σ limiting magnitude in r- band is 26.1 for point sources, which is ≳1 mag deeper than other weak lensing survey in the literature (e.g. the Kilo Degree Survey, KiDS, at VST). The photometric redshifts are estimated using the VOICE u, g, r, i together with near-infrared VIDEO data Y, J, H, Ks. The mean redshift of the shear catalogue is 0.87, considering the shear weight. The effective galaxy number density is 16.35 gal/arcmin2, which is nearly twice the one of KiDS. The performance of LensFit on such a deep dataset was calibrated using VOICE-like mock image simulations. Furthermore, we have analyzed the reliability of the shear catalogue by calculating the star-galaxy cross-correlations, the tomographic shear correlations of two redshift bins and the contaminations of the blended galaxies. As a further sanity check, we have constrained cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. For a flat ΛCDM model we have obtained Σ _8 = σ _8(Ω _m/0.3)^{0.5} = 0.68^{+0.11}_{-0.15}.

Space-based infrared sensors of space target imaging effect analysis

Science.gov (United States)

Dai, Huayu; Zhang, Yasheng; Zhou, Haijun; Zhao, Shuang

2018-02-01

Target identification problem is one of the core problem of ballistic missile defense system, infrared imaging simulation is an important means of target detection and recognition. This paper first established the space-based infrared sensors ballistic target imaging model of point source on the planet's atmosphere; then from two aspects of space-based sensors camera parameters and target characteristics simulated atmosphere ballistic target of infrared imaging effect, analyzed the camera line of sight jitter, camera system noise and different imaging effects of wave on the target.

THE SPACE DENSITY EVOLUTION OF WET AND DRY MERGERS IN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY

International Nuclear Information System (INIS)

Chou, Richard C. Y.; Abraham, Roberto G.; Bridge, Carrie R.

2011-01-01

We analyze 1298 merging galaxies with redshifts up to z = 0.7 from the Canada-France-Hawaii Telescope Legacy Survey, taken from the catalog presented in the work of Bridge et al. By analyzing the internal colors of these systems, we show that the so-called wet and dry mergers evolve in different senses, and quantify the space densities of these systems. The local space density of wet mergers is essentially identical to the local space density of dry mergers. The evolution in the total merger rate is modest out to z ∼ 0.7, although the wet and dry populations have different evolutionary trends. At higher redshifts, dry mergers make a smaller contribution to the total merging galaxy population, but this is offset by a roughly equivalent increase in the contribution from wet mergers. By comparing the mass density function of early-type galaxies to the corresponding mass density function for merging systems, we show that not all the major mergers with the highest masses (M stellar >10 11 M sun ) will end up with the most massive early-type galaxies, unless the merging timescale is dramatically longer than that usually assumed. On the other hand, the usually assumed merging timescale of ∼0.5-1 Gyr is quite consistent with the data if we suppose that only less massive early-type galaxies form via mergers. Since low-intermediate-mass ellipticals are 10-100 times more common than their most massive counterparts, the hierarchical explanation for the origin of early-type galaxies may be correct for the vast majority of early types, even if incorrect for the most massive ones.

Space and Industrial Brine Drying Technologies

Science.gov (United States)

Jones, Harry W.; Wisniewski, Richard S.; Flynn, Michael; Shaw, Hali

2014-01-01

This survey describes brine drying technologies that have been developed for use in space and industry. NASA has long considered developing a brine drying system for the International Space Station (ISS). Possible processes include conduction drying in many forms, spray drying, distillation, freezing and freeze drying, membrane filtration, and electrical processes. Commercial processes use similar technologies. Some proposed space systems combine several approaches. The current most promising candidates for use on the ISS use either conduction drying with membrane filtration or spray drying.

Remapping simulated halo catalogues in redshift space

OpenAIRE

Mead, Alexander; Peacock, John

2014-01-01

We discuss the extension to redshift space of a rescaling algorithm, designed to alter the effective cosmology of a pre-existing simulated particle distribution or catalogue of dark matter haloes. The rescaling approach was initially developed by Angulo & White and was adapted and applied to halo catalogues in real space in our previous work. This algorithm requires no information other than the initial and target cosmological parameters, and it contains no tuned parameters. It is shown here ...

Genetic Algorithm Optimizes Q-LAW Control Parameters

Science.gov (United States)

Lee, Seungwon; von Allmen, Paul; Petropoulos, Anastassios; Terrile, Richard

2008-01-01

A document discusses a multi-objective, genetic algorithm designed to optimize Lyapunov feedback control law (Q-law) parameters in order to efficiently find Pareto-optimal solutions for low-thrust trajectories for electronic propulsion systems. These would be propellant-optimal solutions for a given flight time, or flight time optimal solutions for a given propellant requirement. The approximate solutions are used as good initial solutions for high-fidelity optimization tools. When the good initial solutions are used, the high-fidelity optimization tools quickly converge to a locally optimal solution near the initial solution. Q-law control parameters are represented as real-valued genes in the genetic algorithm. The performances of the Q-law control parameters are evaluated in the multi-objective space (flight time vs. propellant mass) and sorted by the non-dominated sorting method that assigns a better fitness value to the solutions that are dominated by a fewer number of other solutions. With the ranking result, the genetic algorithm encourages the solutions with higher fitness values to participate in the reproduction process, improving the solutions in the evolution process. The population of solutions converges to the Pareto front that is permitted within the Q-law control parameter space.

Space debris mitigation - engineering strategies

Science.gov (United States)

Taylor, E.; Hammond, M.

The problem of space debris pollution is acknowledged to be of growing concern by space agencies, leading to recent activities in the field of space debris mitigation. A review of the current (and near-future) mitigation guidelines, handbooks, standards and licensing procedures has identified a number of areas where further work is required. In order for space debris mitigation to be implemented in spacecraft manufacture and operation, the authors suggest that debris-related criteria need to become design parameters (following the same process as applied to reliability and radiation). To meet these parameters, spacecraft manufacturers and operators will need processes (supported by design tools and databases and implementation standards). A particular aspect of debris mitigation, as compared with conventional requirements (e.g. radiation and reliability) is the current and near-future national and international regulatory framework and associated liability aspects. A framework for these implementation standards is presented, in addition to results of in-house research and development on design tools and databases (including collision avoidance in GTO and SSTO and evaluation of failure criteria on composite and aluminium structures).

Performance Improvement of Near Earth Space Survey (NESS Wide-Field Telescope (NESS-2 Optics

Directory of Open Access Journals (Sweden)

Sung-Yeol Yu

2010-06-01

Full Text Available We modified the optical system of 500 mm wide-field telescope of which point spread function showed an irregularity. The telescope has been operated for Near Earth Space Survey (NESS located at Siding Spring Observatory (SSO in Australia, and the optical system was brought back to Korea in January 2008. After performing a numerical simulation with the tested value of surface figure error of the primary mirror using optical design program, we found that the surface figure error of the mirror should be fabricated less than root mean square (RMS λ/10 in order to obtain a stellar full width at half maximum (FWHM below 28 μm. However, we started to figure the mirror for the target value of RMS λ/20, because system surface figure error would be increased by the error induced by the optical axis adjustment, mirror cell installation, and others. The radius of curvature of the primary mirror was 1,946 mm after the correction. Its measured surface figure error was less than RMS λ/20 on the table of polishing machine, and RMS λ/15 after installation in the primary mirror cell. A test observation performed at Daeduk Observatory at Korea Astronomy and Space Science Institute by utilizing the exiting mount, and resulted in 39.8 μm of stellar FWHM. It was larger than the value from numerical simulation, and showed wing-shaped stellar image. It turned out that the measured-curvature of the secondary mirror, 1,820 mm, was not the same as the designed one, 1,795.977 mm. We fabricated the secondary mirror to the designed value, and finally obtained a stellar FWHM of 27 μm after re-installation of the optical system into SSO NESS Observatory in Australia.

Constraining neutron guide optimizations with phase-space considerations

Energy Technology Data Exchange (ETDEWEB)

Bertelsen, Mads, E-mail: mads.bertelsen@gmail.com; Lefmann, Kim

2016-09-11

We introduce a method named the Minimalist Principle that serves to reduce the parameter space for neutron guide optimization when the required beam divergence is limited. The reduced parameter space will restrict the optimization to guides with a minimal neutron intake that are still theoretically able to deliver the maximal possible performance. The geometrical constraints are derived using phase-space propagation from moderator to guide and from guide to sample, while assuming that the optimized guides will achieve perfect transport of the limited neutron intake. Guide systems optimized using these constraints are shown to provide performance close to guides optimized without any constraints, however the divergence received at the sample is limited to the desired interval, even when the neutron transport is not limited by the supermirrors used in the guide. As the constraints strongly limit the parameter space for the optimizer, two control parameters are introduced that can be used to adjust the selected subspace, effectively balancing between maximizing neutron transport and avoiding background from unnecessary neutrons. One parameter is needed to describe the expected focusing abilities of the guide to be optimized, going from perfectly focusing to no correlation between position and velocity. The second parameter controls neutron intake into the guide, so that one can select exactly how aggressively the background should be limited. We show examples of guides optimized using these constraints which demonstrates the higher signal to noise than conventional optimizations. Furthermore the parameter controlling neutron intake is explored which shows that the simulated optimal neutron intake is close to the analytically predicted, when assuming that the guide is dominated by multiple scattering events.

Space weather effects on ground based technology

Science.gov (United States)

Clark, T.

Space weather can affect a variety of forms of ground-based technology, usually as a result of either the direct effects of the varying geomagnetic field, or as a result of the induced electric field that accompanies such variations. Technologies affected directly by geomagnetic variations include magnetic measurements made d ringu geophysical surveys, and navigation relying on the geomagnetic field as a direction reference, a method that is particularly common in the surveying of well-bores in the oil industry. The most obvious technology affected by induced electric fields during magnetic storms is electric power transmission, where the example of the blackout in Quebec during the March 1989 magnetic storm is widely known. Additionally, space weather effects must be taken into account in the design of active cathodic protection systems on pipelines to protect them against corrosion. Long-distance telecommunication cables may also have to be designed to cope with space weather related effects. This paper reviews the effects of space weather in these different areas of ground-based technology, and provides examples of how mitigation against hazards may be achieved. (The paper does not include the effects of space weather on radio communication or satellite navigation systems).

Space astronomy and astrophysics program by NASA

Science.gov (United States)

Hertz, Paul L.

2014-07-01

The National Aeronautics and Space Administration recently released the NASA Strategic Plan 20141, and the NASA Science Mission Directorate released the NASA 2014 Science Plan3. These strategic documents establish NASA's astrophysics strategic objectives to be (i) to discover how the universe works, (ii) to explore how it began and evolved, and (iii) to search for life on planets around other stars. The multidisciplinary nature of astrophysics makes it imperative to strive for a balanced science and technology portfolio, both in terms of science goals addressed and in missions to address these goals. NASA uses the prioritized recommendations and decision rules of the National Research Council's 2010 decadal survey in astronomy and astrophysics2 to set the priorities for its investments. The NASA Astrophysics Division has laid out its strategy for advancing the priorities of the decadal survey in its Astrophysics 2012 Implementation Plan4. With substantial input from the astrophysics community, the NASA Advisory Council's Astrophysics Subcommittee has developed an astrophysics visionary roadmap, Enduring Quests, Daring Visions5, to examine possible longer-term futures. The successful development of the James Webb Space Telescope leading to a 2018 launch is an Agency priority. One important goal of the Astrophysics Division is to begin a strategic mission, subject to the availability of funds, which follows from the 2010 decadal survey and is launched after the James Webb Space Telescope. NASA is studying a Wide Field Infrared Survey Telescope as its next large astrophysics mission. NASA is also planning to partner with other space agencies on their missions as well as increase the cadence of smaller Principal Investigator led, competitively selected Astrophysics Explorers missions.

Systematic parameter inference in stochastic mesoscopic modeling

Energy Technology Data Exchange (ETDEWEB)

Lei, Huan; Yang, Xiu [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Li, Zhen [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Karniadakis, George Em, E-mail: george_karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)

2017-02-01

We propose a method to efficiently determine the optimal coarse-grained force field in mesoscopic stochastic simulations of Newtonian fluid and polymer melt systems modeled by dissipative particle dynamics (DPD) and energy conserving dissipative particle dynamics (eDPD). The response surfaces of various target properties (viscosity, diffusivity, pressure, etc.) with respect to model parameters are constructed based on the generalized polynomial chaos (gPC) expansion using simulation results on sampling points (e.g., individual parameter sets). To alleviate the computational cost to evaluate the target properties, we employ the compressive sensing method to compute the coefficients of the dominant gPC terms given the prior knowledge that the coefficients are “sparse”. The proposed method shows comparable accuracy with the standard probabilistic collocation method (PCM) while it imposes a much weaker restriction on the number of the simulation samples especially for systems with high dimensional parametric space. Fully access to the response surfaces within the confidence range enables us to infer the optimal force parameters given the desirable values of target properties at the macroscopic scale. Moreover, it enables us to investigate the intrinsic relationship between the model parameters, identify possible degeneracies in the parameter space, and optimize the model by eliminating model redundancies. The proposed method provides an efficient alternative approach for constructing mesoscopic models by inferring model parameters to recover target properties of the physics systems (e.g., from experimental measurements), where those force field parameters and formulation cannot be derived from the microscopic level in a straight forward way.

Study and survey of assembling parameters to a radioactive source production laboratory used to verify equipment

International Nuclear Information System (INIS)

Gauglitz, Erica

2010-01-01

This paper presents a survey of parameters for the proper and safe flooring, doors, windows, fume hoods and others, in a radiochemical laboratory. The layout of each item follows guidelines and national standards of the National Commission of Nuclear Energy (CNEN) and the International Atomic Energy Agency (IAEA), aiming to ensure the radiological protection of workers and environment. The adequate items arrangement in the radiochemical laboratory ensures quality and safety in the production of 57 Co 137 Cs and 133 Ba radioactive sealed sources, with activities 185, 9.3 and 5.4 MBq, respectively. These sources are used to verify meter activity equipment and should be available throughout the Nuclear Medicine Center, following the recommendations of CNEN-NN-3.05 standard R equirements for Radiation Protection and Safety Services for Nuclear Medicine , to verify the activity of radiopharmaceuticals that are administered in patients, for diagnosis and therapy. Verification of measuring activity equipment will be used to perform accuracy, reproducibility and linearity tests, which should show results within the limits specified in the standard CNEN-NN-3.05. (author)

Leisure time activities in space: A survey of astronauts and cosmonauts

Science.gov (United States)

Kelly, Alan D.; Kanas, Nick

Questionnaires were returned from 54 astronauts and cosmonauts which addressed preferences for media and media-generated subjects that could be used to occupy leisure time in space. Ninety-three percent of the respondents had access to records or audio cassettes, and cosmonauts had greater access than astronauts to multiple media. Cosmonauts and long-duration space travelers reported that they missed various media more than their astronaut and short-duration counterparts. Media subjects that related to international events, national events and historical topics were rated as most preferable by all respondents and by several of the respondent groups. The findings are discussed in terms of their relevance for occupying free time during future long-duration manned space missions.

Analysis and Assessment of Parameters Shaping Methane Hazard in Longwall Areas

Directory of Open Access Journals (Sweden)

Eugeniusz Krause

2013-01-01

Full Text Available Increasing coal production concentration and mining in coal seams of high methane content contribute to its growing emission to longwall areas. In this paper, analysis of survey data concerning the assessment of parameters that influence the level of methane hazard in mining areas is presented. The survey was conducted with experts on ventilation and methane hazard in coal mines. The parameters which influence methane hazard in longwall areas were assigned specific weights (numerical values. The summary will show which of the assessed parameters have a strong, or weak, influence on methane hazard in longwall areas close to coal seams of high methane content.

Confronting the sound speed of dark energy with future cluster surveys

DEFF Research Database (Denmark)

Basse, Tobias; Eggers Bjaelde, Ole; Hannestad, Steen

2012-01-01

Future cluster surveys will observe galaxy clusters numbering in the hundred thousands. We consider this work how these surveys can be used to constrain dark energy parameters: in particular, the equation of state parameter w and the non-adiabatic sound speed c_s^2. We demonstrate that, in combin......Future cluster surveys will observe galaxy clusters numbering in the hundred thousands. We consider this work how these surveys can be used to constrain dark energy parameters: in particular, the equation of state parameter w and the non-adiabatic sound speed c_s^2. We demonstrate that......, in combination with Cosmic Microwave Background (CMB) observations from Planck, cluster surveys such as that in the ESA Euclid project will be able to determine a time-independent w with subpercent precision. Likewise, if the dark energy sound horizon falls within the length scales probed by the cluster survey......, then c_s^2 can be pinned down to within an order of magnitude. In the course of this work, we also investigate the process of dark energy virialisation in the presence of an arbitrary sound speed. We find that dark energy clustering and virialisation can lead to dark energy contributing to the total...

Longitudinal Phase Space Tomography with Space Charge

CERN Document Server

Hancock, S; Lindroos, M

2000-01-01

Tomography is now a very broad topic with a wealth of algorithms for the reconstruction of both qualitative and quantitative images. In an extension in the domain of particle accelerators, one of the simplest algorithms has been modified to take into account the non-linearity of large-amplitude synchrotron motion. This permits the accurate reconstruction of longitudinal phase space density from one-dimensional bunch profile data. The method is a hybrid one which incorporates particle tracking. Hitherto, a very simple tracking algorithm has been employed because only a brief span of measured profile data is required to build a snapshot of phase space. This is one of the strengths of the method, as tracking for relatively few turns relaxes the precision to which input machine parameters need to be known. The recent addition of longitudinal space charge considerations as an optional refinement of the code is described. Simplicity suggested an approach based on the derivative of bunch shape with the properties of...

SpaceTech—Postgraduate space education

Science.gov (United States)

de Bruijn, Ferdi J.; Ashford, Edward W.; Larson, Wiley J.

2008-07-01

, Interpersonal Skills, Telecommunications, Earth Observation and Navigation. A group CCP, a major asset of this unique program, is a focused project, aimed at the formation of a credible virtual commercial space-related business. Participants exercise space systems engineering fundamentals as well as marketing and business engineering tools, with the goal of creating a financially viable business opportunity. They then present the result, in the form of an unsolicited proposal to potential investors, as well as a varied group of engineers, managers and executives from the space community. During the CCP, participants learn the ties between mission and system design and the potential return to investors. They develop an instinct for the technical concepts and which of the parameters to adjust to make their newly conceived business more effective and profitable.

Will kinematic Sunyaev-Zel'dovich measurements enhance the science return from galaxy redshift surveys?

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Naonori S.; Okumura, Teppei [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo, Chiba 277-8582 (Japan); Spergel, David N., E-mail: nao.s.sugiyama@gmail.com, E-mail: tokumura@asiaa.sinica.edu.tw, E-mail: dns@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton NJ 08544-0010 (United States)

2017-01-01

Yes. Future CMB experiments such as Advanced ACTPol and CMB-S4 should achieve measurements with S/N of > 0.1 for the typical host halo of galaxies in redshift surveys. These measurements will provide complementary measurements of the growth rate of large scale structure f and the expansion rate of the Universe H to galaxy clustering measurements. This paper emphasizes that there is significant information in the anisotropy of the relative pairwise kSZ measurements. We expand the relative pairwise kSZ power spectrum in Legendre polynomials and consider up to its octopole. Assuming that the noise in the filtered maps is uncorrelated between the positions of galaxies in the survey, we derive a simple analytic form for the power spectrum covariance of the relative pairwise kSZ temperature in redshift space. While many previous studies have assumed optimistically that the optical depth of the galaxies τ{sub T} in the survey is known, we marginalize over τ{sub T}, to compute constraints on the growth rate f and the expansion rate H . For realistic survey parameters, we find that combining kSZ and galaxy redshift survey data reduces the marginalized 1-σ errors on H and f to ∼50-70% compared to the galaxy-only analysis.

Comparison of the Carbon System Parameters at the Global CO2 Survey Crossover Locations in the North and South Pacific Ocean, 1990-1996

Energy Technology Data Exchange (ETDEWEB)

Feely, Richard A [NOAA, Pacific Marine Environmental Laboratory (PMEL); Lamb, Marilyn F. [NOAA, Pacific Marine Environmental Laboratory (PMEL); Greeley, Dana J. [NOAA, Pacific Marine Environmental Laboratory (PMEL); Wanninkhof, Rik [NOAA, Atlantic Oceanographic and Meteorological Laboratory (AOML)

1999-10-01

As a collaborative program to measure global ocean carbon inventories and provide estimates of the anthropogenic carbon dioxide (C02) uptake by the oceans. the National Oceanic and Atmospheric Administration and the U.S. Department of Energy have sponsored the collection of ocean carbon measurements as part of the World Ocean Circulation Experiment and Ocean-Atmosphere Carbon Exchange Study cruises. The cruises discussed here occurred in the North and South Pacific from 1990 through 1996. The carbon parameters from these 30 crossover locations have been compared to ensure that a consistent global data set emerges from the survey cruises. !'he results indicate that for dissolved inorganic carbon. fugacity of C02• and pH. the a~:,rreements at most crossover locations are well within the design specifications for the global CO) survey: whereas. in the case of total alkaliniry. the agreement between crossover locations is not as close.

Model-independent constraints on modified gravity from current data and from the Euclid and SKA future surveys

Energy Technology Data Exchange (ETDEWEB)

Taddei, Laura; Martinelli, Matteo; Amendola, Luca, E-mail: taddei@thphys.uni-heidelberg.de, E-mail: martinelli@lorentz.leidenuniv.nl, E-mail: amendola@thphys.uni-heidelberg.de [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)

2016-12-01

The aim of this paper is to constrain modified gravity with redshift space distortion observations and supernovae measurements. Compared with a standard ΛCDM analysis, we include three additional free parameters, namely the initial conditions of the matter perturbations, the overall perturbation normalization, and a scale-dependent modified gravity parameter modifying the Poisson equation, in an attempt to perform a more model-independent analysis. First, we constrain the Poisson parameter Y (also called G {sub eff}) by using currently available f σ{sub 8} data and the recent SN catalog JLA. We find that the inclusion of the additional free parameters makes the constraints significantly weaker than when fixing them to the standard cosmological value. Second, we forecast future constraints on Y by using the predicted growth-rate data for Euclid and SKA missions. Here again we point out the weakening of the constraints when the additional parameters are included. Finally, we adopt as modified gravity Poisson parameter the specific Horndeski form, and use scale-dependent forecasts to build an exclusion plot for the Yukawa potential akin to the ones realized in laboratory experiments, both for the Euclid and the SKA surveys.

Model-independent constraints on modified gravity from current data and from the Euclid and SKA future surveys

International Nuclear Information System (INIS)

Taddei, Laura; Martinelli, Matteo; Amendola, Luca

2016-01-01

The aim of this paper is to constrain modified gravity with redshift space distortion observations and supernovae measurements. Compared with a standard ΛCDM analysis, we include three additional free parameters, namely the initial conditions of the matter perturbations, the overall perturbation normalization, and a scale-dependent modified gravity parameter modifying the Poisson equation, in an attempt to perform a more model-independent analysis. First, we constrain the Poisson parameter Y (also called G eff ) by using currently available f σ 8 data and the recent SN catalog JLA. We find that the inclusion of the additional free parameters makes the constraints significantly weaker than when fixing them to the standard cosmological value. Second, we forecast future constraints on Y by using the predicted growth-rate data for Euclid and SKA missions. Here again we point out the weakening of the constraints when the additional parameters are included. Finally, we adopt as modified gravity Poisson parameter the specific Horndeski form, and use scale-dependent forecasts to build an exclusion plot for the Yukawa potential akin to the ones realized in laboratory experiments, both for the Euclid and the SKA surveys.

The role of interactions in galaxy evolution: A new perspective from the CALIFA and MaNGA Integral Field Spectroscopic surveys.

Science.gov (United States)

Barrera-Ballesteros, J. K.; Sanchez, S. F.; Califa Collaboration

2016-06-01

Interactions and mergers have been playing a paramount role to understand how galaxies evolve. In recent years integral field spectroscopic (IFS) observations have become routinely allowing researchers to conduct large IFS surveys. In this context, these surveys are providing a new observational scenario to probe the properties of galaxies at different stages of the interaction —from close pairs to post-merger galaxies. Even more, these surveys also include homogeneous observations of non-interacting galaxies which in turns allows to distinguish the processes induce by secular evolution from those driven by interactions. In this talk, We review the studies of interacting studies from the CALIFA survey. They consider from the thorough analysis of a single interactive systems (e.g., the Mice, Wild et al. 2014) to the the statistical study of physical properties of a large sample of interacting/merging galaxies such as their internal structure via their stellar and gas line-of-sight kinematic maps (Barrera-Ballesteros et al. 2015a) or the spatial distribution of the star-forming gas in these galaxies (Barrera-Ballesteros et al. 2015b). Then we present some of the on-going studies within the MaNGA survey. Due to its statistical power (sample size ~10000 objects), this survey will allow us to probe the properties of galaxies in a wide range of the interaction-parameter space. This in turn provides a unique view on the key parameters that affect the internal structure and properties of galaxies during the interaction and subsequent merger.

Impact parameter analysis and soft QCD dynamics

International Nuclear Information System (INIS)

Carvalho, P.A.S.; Martini, A.F.; Menon, M.J.

2002-01-01

In a recent paper, based on the hypothesis of light-cone dipole representation for gluon Bremsstrahlung, Kopeliovich et al. developed a dynamical model for the elastic hadronic amplitude. The model has been applied to pp and p (bar) p scattering and the effects of unitarity and peripheral interactions have been investigated in the impact parameter representation. In this communication, making use of a model independent extraction of the scattering amplitude in the impact parameter space (early developed), we represent a comparative study between the predictions from the dynamical model and the impact parameter analysis. (author)

Space-Time Fractional Diffusion-Advection Equation with Caputo Derivative

Directory of Open Access Journals (Sweden)

José Francisco Gómez Aguilar

2014-01-01

Full Text Available An alternative construction for the space-time fractional diffusion-advection equation for the sedimentation phenomena is presented. The order of the derivative is considered as 0<β, γ≤1 for the space and time domain, respectively. The fractional derivative of Caputo type is considered. In the spatial case we obtain the fractional solution for the underdamped, undamped, and overdamped case. In the temporal case we show that the concentration has amplitude which exhibits an algebraic decay at asymptotically large times and also shows numerical simulations where both derivatives are taken in simultaneous form. In order that the equation preserves the physical units of the system two auxiliary parameters σx and σt are introduced characterizing the existence of fractional space and time components, respectively. A physical relation between these parameters is reported and the solutions in space-time are given in terms of the Mittag-Leffler function depending on the parameters β and γ. The generalization of the fractional diffusion-advection equation in space-time exhibits anomalous behavior.

Gaia , an all sky astrometric and photometric survey

International Nuclear Information System (INIS)

Carrasco, J.M.

2017-01-01

Gaia space mission includes a low resolution spectroscopic instrument to classify and parametrize the observed sources. Gaia is a full-sky unbiased survey down to about 20th magnitude. The scanning law yields a rather uniform coverage of the sky over the full mission. The data reduction is a global one over the full mission. Both sky coverage and data reduction strategy ensure an unprecedented all-sky homogeneous spectrophotometric survey. Certainly, that survey is of interest for future on-ground and space projects (LSST, PLATO, EUCLID, ...). This work addresses the exploitation of the Gaia spectrophotometry as standard photometry reference through the discussion of the sky coverage, the spectrophotometric precision and the expected uncertainties of the synthetic photometry derived from the low resolution Gaia spectra and photometry.

Integrated Logistics Support Analysis of the International Space Station Alpha, Background and Summary of Mathematical Modeling and Failure Density Distributions Pertaining to Maintenance Time Dependent Parameters

Science.gov (United States)

Sepehry-Fard, F.; Coulthard, Maurice H.

1995-01-01

The process of predicting the values of maintenance time dependent variable parameters such as mean time between failures (MTBF) over time must be one that will not in turn introduce uncontrolled deviation in the results of the ILS analysis such as life cycle costs, spares calculation, etc. A minor deviation in the values of the maintenance time dependent variable parameters such as MTBF over time will have a significant impact on the logistics resources demands, International Space Station availability and maintenance support costs. There are two types of parameters in the logistics and maintenance world: a. Fixed; b. Variable Fixed parameters, such as cost per man hour, are relatively easy to predict and forecast. These parameters normally follow a linear path and they do not change randomly. However, the variable parameters subject to the study in this report such as MTBF do not follow a linear path and they normally fall within the distribution curves which are discussed in this publication. The very challenging task then becomes the utilization of statistical techniques to accurately forecast the future non-linear time dependent variable arisings and events with a high confidence level. This, in turn, shall translate in tremendous cost savings and improved availability all around.

U.S. Geological Survey distribution of European Space Agency's Sentinel-2 data

Science.gov (United States)

Pieschke, Renee L.

2017-03-31

A partnership established between the European Space Agency (ESA) and the U.S. Geological Survey (USGS) allows for USGS storage and redistribution of images acquired by the MultiSpectral Instrument (MSI) on the European Union's Sentinel-2 satellite mission. The MSI data are acquired from a pair of satellites, Sentinel-2A and Sentinel-2B, which are part of a larger set of ESA missions focusing on different aspects of Earth observation. The primary purpose of the Sentinel-2 series is to collect multispectral imagery over the Earth’s land surfaces, large islands, and inland and coastal waters. Sentinel-2A was launched in 2015 and Sentinel-2B launched in 2017.The collaborative effort between ESA and USGS provides for public access and redistribution of global acquisitions of Sentinel-2 data at no cost, which allows users to download the MSI imagery from USGS access systems such as Earth- Explorer, in addition to the ESA Sentinels Scientific Data Hub. The MSI sensor acquires 13 spectral bands that are highly complementary to data acquired by the USGS Landsat 8 Operational Land Imager (OLI) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). The product options from USGS include a Full-Resolution Browse (FRB) image product generated by USGS, along with a 100-kilometer (km) by 100-km tile-based Level-1C top-of-atmosphere (TOA) reflectance product that is very similar (but not identical) to the currently (2017) distributed ESA Level 1C product.

Systematics of nuclear level density parameters

International Nuclear Information System (INIS)

Bucurescu, Dorel; Egidy, Till von

2005-01-01

The level density parameters for the back-shifted Fermi gas (both without and with energy-dependent level density parameter) and the constant temperature models have been determined for 310 nuclei between 18 F and 251 Cf by fitting the complete level schemes at low excitation energies and the s-wave neutron resonance spacings at the neutron binding energies. Simple formulae are proposed for the description of the two parameters of each of these models, which involve only quantities available from the mass tables. These formulae may constitute a reliable tool for extrapolating to nuclei far from stability, where nuclear level densities cannot be measured

Ω-deformed SYM on a Gibbons-Hawking space

International Nuclear Information System (INIS)

Dey, Anindya

2015-01-01

We study an N=2, pure U(1) SYM theory on a Gibbons-Hawking space Ω-deformed using the U(1) isometry. The resultant 3D theory, after an appropriate “Nekrasov-Witten" change of variables, is asymptotically equivalent to the undeformed theory at spatial infinity but differs from it as one approaches the NUT centers which are fixed points under the U(1) action. The 3D theory may be recast in the form of a generalized hyperkähler sigma model introduced in http://dx.doi.org/10.1007/JHEP04(2014)158 where the target space is a one-parameter family of hyperkähler spaces. The hyperkähler fibers have a preferred complex structure which for the deformed theory depends on the parameter of Ω-deformation. The metric on the hyperkähler fiber can be reduced to a standard metric on ℂ×T 2 with the modular parameter of the torus depending explicitly on the Ω-deformation parameter. The contribution of the NUT center to the sigma model path integral, expected to be a holomorphic section of a holomorphic line bundle over the target space on grounds of supersymmetry, turns out to be a Jacobi theta function in terms of certain “deformed" variables.

Sparsity regularization for parameter identification problems

International Nuclear Information System (INIS)

Jin, Bangti; Maass, Peter

2012-01-01

The investigation of regularization schemes with sparsity promoting penalty terms has been one of the dominant topics in the field of inverse problems over the last years, and Tikhonov functionals with ℓ p -penalty terms for 1 ⩽ p ⩽ 2 have been studied extensively. The first investigations focused on regularization properties of the minimizers of such functionals with linear operators and on iteration schemes for approximating the minimizers. These results were quickly transferred to nonlinear operator equations, including nonsmooth operators and more general function space settings. The latest results on regularization properties additionally assume a sparse representation of the true solution as well as generalized source conditions, which yield some surprising and optimal convergence rates. The regularization theory with ℓ p sparsity constraints is relatively complete in this setting; see the first part of this review. In contrast, the development of efficient numerical schemes for approximating minimizers of Tikhonov functionals with sparsity constraints for nonlinear operators is still ongoing. The basic iterated soft shrinkage approach has been extended in several directions and semi-smooth Newton methods are becoming applicable in this field. In particular, the extension to more general non-convex, non-differentiable functionals by variational principles leads to a variety of generalized iteration schemes. We focus on such iteration schemes in the second part of this review. A major part of this survey is devoted to applying sparsity constrained regularization techniques to parameter identification problems for partial differential equations, which we regard as the prototypical setting for nonlinear inverse problems. Parameter identification problems exhibit different levels of complexity and we aim at characterizing a hierarchy of such problems. The operator defining these inverse problems is the parameter-to-state mapping. We first summarize some

National Uranium Resource Evaluation Program. Hydrogeochemical and stream sediment pilot survey of Llano area, Texas

International Nuclear Information System (INIS)

Nichols, C.E.; Kane, V.E.; Minkin, S.C.; Cagle, G.W.

1976-01-01

A pilot geochemical survey of the Llano, Texas, area was conducted during February and March 1976. The purpose of this work was to prepare for a subsequent reconnaissance geochemical survey of uranium in Central Texas. Stream sediment, stream water, well water, and plant ash from five geologic areas were analyzed in the laboratory for approximately 25 parameters. Examples of anomalous values in stream sediment and stream water indicate the usefulness of both sample types in identifying anomalies at a regional reconnaissance-scale station spacing of approximately 5 km (3 mi). Groundwater samples, which generally best indicate the geochemistry of formations at depth in a survey of this type, represent another important tool in detecting uranium mineralization. Anomalies in San Saba County are associated with the Marble Falls-Smithwich Formations and the Strawn Series (Pennsylvanian), the Houy Formation (Devonian and lower Mississippian), and the Hickory Sandstone Member of the Riley Formation (Cambrian). In Burnet County anomalous values are due to the influence of the Valley Spring Formation (Precambrian); and in Blanco County anomalies are found associated with the Riley Formation

The Extended Northern ROSAT Galaxy Cluster Survey (NORAS II). I. Survey Construction and First Results

International Nuclear Information System (INIS)

Böhringer, Hans; Chon, Gayoung; Trümper, Joachim; Retzlaff, Jörg; Meisenheimer, Klaus; Schartel, Norbert

2017-01-01

As the largest, clearly defined building blocks of our universe, galaxy clusters are interesting astrophysical laboratories and important probes for cosmology. X-ray surveys for galaxy clusters provide one of the best ways to characterize the population of galaxy clusters. We provide a description of the construction of the NORAS II galaxy cluster survey based on X-ray data from the northern part of the ROSAT All-Sky Survey. NORAS II extends the NORAS survey down to a flux limit of 1.8 × 10 −12 erg s −1 cm −2 (0.1–2.4 keV), increasing the sample size by about a factor of two. The NORAS II cluster survey now reaches the same quality and depth as its counterpart, the southern REFLEX II survey, allowing us to combine the two complementary surveys. The paper provides information on the determination of the cluster X-ray parameters, the identification process of the X-ray sources, the statistics of the survey, and the construction of the survey selection function, which we provide in numerical format. Currently NORAS II contains 860 clusters with a median redshift of z  = 0.102. We provide a number of statistical functions, including the log N –log S and the X-ray luminosity function and compare these to the results from the complementary REFLEX II survey. Using the NORAS II sample to constrain the cosmological parameters, σ 8 and Ω m , yields results perfectly consistent with those of REFLEX II. Overall, the results show that the two hemisphere samples, NORAS II and REFLEX II, can be combined without problems into an all-sky sample, just excluding the zone of avoidance.

The Extended Northern ROSAT Galaxy Cluster Survey (NORAS II). I. Survey Construction and First Results

Energy Technology Data Exchange (ETDEWEB)

Böhringer, Hans; Chon, Gayoung; Trümper, Joachim [Max-Planck-Institut für Extraterrestrische Physik, D-85748 Garching (Germany); Retzlaff, Jörg [ESO, D-85748 Garching (Germany); Meisenheimer, Klaus [Max-Planck-Institut für Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schartel, Norbert [ESAC, Camino Bajo del Castillo, Villanueva de la Cañada, E-28692 Madrid (Spain)

2017-05-01

As the largest, clearly defined building blocks of our universe, galaxy clusters are interesting astrophysical laboratories and important probes for cosmology. X-ray surveys for galaxy clusters provide one of the best ways to characterize the population of galaxy clusters. We provide a description of the construction of the NORAS II galaxy cluster survey based on X-ray data from the northern part of the ROSAT All-Sky Survey. NORAS II extends the NORAS survey down to a flux limit of 1.8 × 10{sup −12} erg s{sup −1} cm{sup −2} (0.1–2.4 keV), increasing the sample size by about a factor of two. The NORAS II cluster survey now reaches the same quality and depth as its counterpart, the southern REFLEX II survey, allowing us to combine the two complementary surveys. The paper provides information on the determination of the cluster X-ray parameters, the identification process of the X-ray sources, the statistics of the survey, and the construction of the survey selection function, which we provide in numerical format. Currently NORAS II contains 860 clusters with a median redshift of z  = 0.102. We provide a number of statistical functions, including the log N –log S and the X-ray luminosity function and compare these to the results from the complementary REFLEX II survey. Using the NORAS II sample to constrain the cosmological parameters, σ {sub 8} and Ω{sub m}, yields results perfectly consistent with those of REFLEX II. Overall, the results show that the two hemisphere samples, NORAS II and REFLEX II, can be combined without problems into an all-sky sample, just excluding the zone of avoidance.

The legal regime for private space tourism activities—An overview

Science.gov (United States)

Hobe, Stephan

2010-06-01

"Space tourism" denotes any commercial activity that offers customers direct or indirect experience with space travel. Various models for space tourism activities exist including the use of an aircraft and/or spacecraft. The paper surveys some of the most important legal aspects relevant to space tourism activities, such as, the delimitation of airspace and outer space, the applicable legal regime and the definition of aircraft and space object, authorization, registration, liability, as well as the legal status of space tourists.

Space Radiation Environment Prediction for VLSI microelectronics devices onboard a LEO Satellite using OMERE-Trad Software

Science.gov (United States)

Sajid, Muhammad

This tutorial/survey paper presents the assessment/determination of level of hazard/threat to emerging microelectronics devices in Low Earth Orbit (LEO) space radiation environment with perigee at 300 Km, apogee at 600Km altitude having different orbital inclinations to predict the reliability of onboard Bulk Built-In Current Sensor (BBICS) fabricated in 350nm technology node at OptMA Lab. UFMG Brazil. In this context, the various parameters for space radiation environment have been analyzed to characterize the ionizing radiation environment effects on proposed BBICS. The Space radiation environment has been modeled in the form of particles trapped in Van-Allen radiation belts(RBs), Energetic Solar Particles Events (ESPE) and Galactic Cosmic Rays (GCR) where as its potential effects on Device- Under-Test (DUT) has been predicted in terms of Total Ionizing Dose (TID), Single-Event Effects (SEE) and Displacement Damage Dose (DDD). Finally, the required mitigation techniques including necessary shielding requirements to avoid undesirable effects of radiation environment at device level has been estimated /determined with assumed standard thickness of Aluminum shielding. In order to evaluate space radiation environment and analyze energetic particles effects on BBICS, OMERE toolkit developed by TRAD was utilized.

Student Facebook groups as a third space

DEFF Research Database (Denmark)

Aaen, Janus Holst; Dalsgaard, Christian

2016-01-01

-institutional, personal space of the Facebook network. The main study of the article examines six student-managed Facebook groups and provides an analysis of a total of 2247 posts and 12,217 comments. Furthermore, the study draws on group interviews with students from 17 Danish upper secondary schools and a survey......The paper examines educational potentials of Facebook groups that are created and managed by students without any involvement from teachers. The objective is to study student-managed Facebook groups as a ‘third space' between the institutional space of teacher-managed Facebook groups and the non...... answered by 932 students from 25 schools. Based on the survey and interviews, the paper concludes that Facebook is an important educational tool for students in Danish upper secondary schools to receive help on homework and assignments. Furthermore, on the basis of the analysis of Facebook groups...

Survey of the US materials processing and manufacturing in space program

Science.gov (United States)

Mckannan, E. C.

1981-01-01

To promote potential commercial applications of low-g technology, the materials processing and manufacturing in space program is structured to: (1) analyze the scientific principles of gravitational effects on processes used in producing materials; (2) apply the research toward the technology used to control production process (on Earth or in space, as appropriate); and (3) establish the legal and managerial framework for commercial ventures. Presently federally funded NASA research is described as well as agreements for privately funded commercial activity, and a proposed academic participation process. The future scope of the program and related capabilities using ground based facilities, aircraft, sounding rockets, and space shuttles are discussed. Areas of interest described include crystal growth; solidification of metals and alloys; containerless processing; fluids and chemical processes (including biological separation processes); and processing extraterrestrial materials.

A Real-Time Apple Grading System Using Multicolor Space

Directory of Open Access Journals (Sweden)

Hayrettin Toylan

2014-01-01

Full Text Available This study was focused on the multicolor space which provides a better specification of the color and size of the apple in an image. In the study, a real-time machine vision system classifying apples into four categories with respect to color and size was designed. In the analysis, different color spaces were used. As a result, 97% identification success for the red fields of the apple was obtained depending on the values of the parameter “a” of CIE L*a*b*color space. Similarly, 94% identification success for the yellow fields was obtained depending on the values of the parameter y of CIE XYZ color space. With the designed system, three kinds of apples (Golden, Starking, and Jonagold were investigated by classifying them into four groups with respect to two parameters, color and size. Finally, 99% success rate was achieved in the analyses conducted for 595 apples.

The VIMOS Public Extragalactic Redshift Survey (VIPERS). Gravity test from the combination of redshift-space distortions and galaxy-galaxy lensing at 0.5 < z < 1.2

Science.gov (United States)

de la Torre, S.; Jullo, E.; Giocoli, C.; Pezzotta, A.; Bel, J.; Granett, B. R.; Guzzo, L.; Garilli, B.; Scodeggio, M.; Bolzonella, M.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Branchini, E.; Coupon, J.; De Lucia, G.; Ilbert, O.; Moutard, T.; Moscardini, L.; Peacock, J. A.; Metcalf, R. B.; Prada, F.; Yepes, G.

2017-12-01

We carry out a joint analysis of redshift-space distortions and galaxy-galaxy lensing, with the aim of measuring the growth rate of structure; this is a key quantity for understanding the nature of gravity on cosmological scales and late-time cosmic acceleration. We make use of the final VIPERS redshift survey dataset, which maps a portion of the Universe at a redshift of z ≃ 0.8, and the lensing data from the CFHTLenS survey over the same area of the sky. We build a consistent theoretical model that combines non-linear galaxy biasing and redshift-space distortion models, and confront it with observations. The two probes are combined in a Bayesian maximum likelihood analysis to determine the growth rate of structure at two redshifts z = 0.6 and z = 0.86. We obtain measurements of fσ8(0.6) = 0.48 ± 0.12 and fσ8(0.86) = 0.48 ± 0.10. The additional galaxy-galaxy lensing constraint alleviates galaxy bias and σ8 degeneracies, providing direct measurements of f and σ8: [f(0.6),σ8(0.6)] = [0.93 ± 0.22,0.52 ± 0.06] and [f(0.86),σ8(0.86)] = [0.99 ± 0.19,0.48 ± 0.04]. These measurements are statistically consistent with a Universe where the gravitational interactions can be described by General Relativity, although they are not yet accurate enough to rule out some commonly considered alternatives. Finally, as a complementary test we measure the gravitational slip parameter, EG, for the first time at z > 0.6. We find values of E̅G(0.6) = 0.16±0.09 and E̅G(0.86) = 0.09±0.07, when EG is averaged over scales above 3 h-1 Mpc. We find that our EG measurements exhibit slightly lower values than expected for standard relativistic gravity in a ΛCDM background, although the results are consistent within 1-2σ. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT

User participation in urban green spaces

DEFF Research Database (Denmark)

Fors, Hanna; Molin, Julie Frøik; Murphyc, Melissa Anna

2015-01-01

The provision and administration of high quality urban public green spaces intertwines issues of planning, design, management and maintenance with governance. The benefits of such spaces are often tied to social justice, public health and recreation, biodiversity and helping cities to deal...... with climate change. International policies and changes in public administration have encouraged user participation across multiple phases of green space development. Although sceptics towards participation are easily found supporting arguments sometimes stand without critique, not questioning how...... participation affects the physical quality of green spaces. This literature review surveyed empirical scientific studies seeking to answer the following research question: How does research to date reflect over user participation's contribution to public urban green space quality? The review includes 31...

The Status of Development of Electromagnetic Pumps for Space Application

International Nuclear Information System (INIS)

Kwak, J. S.; Kim, K. H.; Jeong, J. S.; Kim, Hee Reyoung

2013-01-01

Korea lunched this research as a part of the small nuclear power generation technology development for space. In this study, investigated are the basic principle and types of electromagnetic pump and the trend of electromagnetic pump technology development in foreign nations. The survey and analysis give the understanding of the suitability and prospect of electromagnetic pumps as space application technology in Korea. The analysis on the status of the development of electromagnetic pumps was carried out for the application to space environment. It was found that USA was approaching the research and development of electromagnetic pumps for space application. Most electromagnetic pumps surveyed have the efficiency between 35% and 50% where that of AC conduction pump is less than 6%. Further study was thought to have to be given for the mechanical and material characteristics, and the applicability of electromagnetic pumps for space nuclear reactor

Using FOSM-Based Data Worth Analyses to Design Geophysical Surveys to Reduce Uncertainty in a Regional Groundwater Model Update

Science.gov (United States)

Smith, B. D.; White, J.; Kress, W. H.; Clark, B. R.; Barlow, J.

2016-12-01

Hydrogeophysical surveys have become an integral part of understanding hydrogeological frameworks used in groundwater models. Regional models cover a large area where water well data is, at best, scattered and irregular. Since budgets are finite, priorities must be assigned to select optimal areas for geophysical surveys. For airborne electromagnetic (AEM) geophysical surveys, optimization of mapping depth and line spacing needs to take in account the objectives of the groundwater models. The approach discussed here uses a first-order, second-moment (FOSM) uncertainty analyses which assumes an approximate linear relation between model parameters and observations. This assumption allows FOSM analyses to be applied to estimate the value of increased parameter knowledge to reduce forecast uncertainty. FOSM is used to facilitate optimization of yet-to-be-completed geophysical surveying to reduce model forecast uncertainty. The main objective of geophysical surveying is assumed to estimate values and spatial variation in hydrologic parameters (i.e. hydraulic conductivity) as well as map lower permeability layers that influence the spatial distribution of recharge flux. The proposed data worth analysis was applied to Mississippi Embayment Regional Aquifer Study (MERAS) which is being updated. The objective of MERAS is to assess the ground-water availability (status and trends) of the Mississippi embayment aquifer system. The study area covers portions of eight states including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The active model grid covers approximately 70,000 square miles, and incorporates some 6,000 miles of major rivers and over 100,000 water wells. In the FOSM analysis, a dense network of pilot points was used to capture uncertainty in hydraulic conductivity and recharge. To simulate the effect of AEM flight lines, the prior uncertainty for hydraulic conductivity and recharge pilots along potential flight lines was

Quantum mechanics in an evolving Hilbert space

Science.gov (United States)

Artacho, Emilio; O'Regan, David D.

2017-03-01

Many basis sets for electronic structure calculations evolve with varying external parameters, such as moving atoms in dynamic simulations, giving rise to extra derivative terms in the dynamical equations. Here we revisit these derivatives in the context of differential geometry, thereby obtaining a more transparent formalization, and a geometrical perspective for better understanding the resulting equations. The effect of the evolution of the basis set within the spanned Hilbert space separates explicitly from the effect of the turning of the space itself when moving in parameter space, as the tangent space turns when moving in a curved space. New insights are obtained using familiar concepts in that context such as the Riemann curvature. The differential geometry is not strictly that for curved spaces as in general relativity, a more adequate mathematical framework being provided by fiber bundles. The language used here, however, will be restricted to tensors and basic quantum mechanics. The local gauge implied by a smoothly varying basis set readily connects with Berry's formalism for geometric phases. Generalized expressions for the Berry connection and curvature are obtained for a parameter-dependent occupied Hilbert space spanned by nonorthogonal Wannier functions. The formalism is applicable to basis sets made of atomic-like orbitals and also more adaptative moving basis functions (such as in methods using Wannier functions as intermediate or support bases), but should also apply to other situations in which nonorthogonal functions or related projectors should arise. The formalism is applied to the time-dependent quantum evolution of electrons for moving atoms. The geometric insights provided here allow us to propose new finite-difference time integrators, and also better understand those already proposed.

Assessment of study space usage in the Kenneth Dike Library ...

African Journals Online (AJOL)

This paper explored the actual use of the physical space in Kenneth Dike Library by the students' population, the role these spaces are playing for learning and for related services in the university of Ibadan academic environment. It looked at the suitability of available spaces and suggestions for improvement. Survey ...

Robust Parameter Coordination for Multidisciplinary Design

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

This paper introduced a robust parameter coordination method to analyze parameter uncertainties so as to predict conflicts and coordinate parameters in multidisciplinary design. The proposed method is based on constraints network, which gives a formulated model to analyze the coupling effects between design variables and product specifications. In this model, interval boxes are adopted to describe the uncertainty of design parameters quantitatively to enhance the design robustness. To solve this constraint network model, a general consistent algorithm framework is designed and implemented with interval arithmetic and the genetic algorithm, which can deal with both algebraic and ordinary differential equations. With the help of this method, designers could infer the consistent solution space from the given specifications. A case study involving the design of a bogie dumping system demonstrates the usefulness of this approach.

METHODOLOGY FOR HYDRAULIC CALCULATION OF RIVER REGULATION AND DETERMINATION OF DIKE PARAMETERS

Directory of Open Access Journals (Sweden)

E. I. Mikhnevich

2017-01-01

Full Text Available Territory protection against flood water inundation and creation of polder systems are carried out with the help of protection dikes. One of the main requirements to the composition of polder systems in flood plains is a location of border dikes beyond meander belt in order to avoid their erosion when meander development occurs. Meander belt width can be determined on the basis of the analysis of multi-year land surveying pertaining top river-bed building and in the case when such data is not available this parameter is calculated in accordance with the Snishchenko formula. While banking-up a river bed a flooded area is decreasing and, consequently, water level in inter-dike space and rate of flood water are significantly increasing. For this reason it is necessary to locate dikes at a such distance from a river bed which will not cause rather high increase in water level and flow velocity in the inter-dike space. Methodology for hydraulic calculation of river regulation has been developed in order to substantiate design parameters for levee systems, creation of favourable hydraulic regime in these systems and provision of sustainability for dikes. Its main elements are calculations of pass-through capacity of the leveed channel and rise of water level in inter-dike space, and distance between dikes and their crest level. Peculiar feature of the proposed calculated formulae is an interaction consideration of channel and inundated flows. Their mass-exchanging process results in slowing-down of the channel flow and acceleration of the inundated flow. This occurrence is taken into account and coefficients of kinematic efficiency are introduced to the elements of water flow rate in the river channel and flood plain, respectively. The adduced dependencies for determination of a dike crest level (consequently their height take into consideration a rise of water level in inter-dike space for two types of polder systems: non-inundable (winter dikes with

The WIRED Survey. IV. New Dust Disks from the McCook & Sion White Dwarf Catalog

Science.gov (United States)

Hoard, D.W.; Debes, John H.; Wachter, Stefanie; Leisawitz, David T.; Cohen, Martin

2013-01-01

We have compiled photometric data from the Wide-field Infrared Survey Explorer All Sky Survey and other archival sources for the more than 2200 objects in the original McCook & Sion Catalog of Spectroscopically Identified White Dwarfs. We applied color-selection criteria to identify 28 targets whose infrared spectral energy distributions depart from the expectation for the white dwarf photosphere alone. Seven of these are previously known white dwarfs with circumstellar dust disks, five are known central stars of planetary nebulae, and six were excluded for being known binaries or having possible contamination of their infrared photometry. We fit white dwarf models to the spectral energy distributions of the remaining ten targets, and find seven new candidates with infrared excess suggesting the presence of a circumstellar dust disk. We compare the model dust disk properties for these new candidates with a comprehensive compilation of previously published parameters for known white dwarfs with dust disks. It is possible that the current census of white dwarfs with dust disks that produce an excess detectable at K-band and shorter wavelengths is close to complete for the entire sample of known WDs to the detection limits of existing near-IR all-sky surveys. The white dwarf dust disk candidates now being found using longer wavelength infrared data are drawn from a previously underrepresented region of parameter space, in which the dust disks are overall cooler, narrower in radial extent, and/or contain fewer emitting grains.

A METHOD FOR SELF-CALIBRATION IN SATELLITE WITH HIGH PRECISION OF SPACE LINEAR ARRAY CAMERA

Directory of Open Access Journals (Sweden)

W. Liu

2016-06-01

Full Text Available At present, the on-orbit calibration of the geometric parameters of a space surveying camera is usually processed by data from a ground calibration field after capturing the images. The entire process is very complicated and lengthy and cannot monitor and calibrate the geometric parameters in real time. On the basis of a large number of on-orbit calibrations, we found that owing to the influence of many factors, e.g., weather, it is often difficult to capture images of the ground calibration field. Thus, regular calibration using field data cannot be ensured. This article proposes a real time self-calibration method for a space linear array camera on a satellite using the optical auto collimation principle. A collimating light source and small matrix array CCD devices are installed inside the load system of the satellite; these use the same light path as the linear array camera. We can extract the location changes of the cross marks in the matrix array CCD to determine the real-time variations in the focal length and angle parameters of the linear array camera. The on-orbit status of the camera is rapidly obtained using this method. On one hand, the camera’s change regulation can be mastered accurately and the camera’s attitude can be adjusted in a timely manner to ensure optimal photography; in contrast, self-calibration of the camera aboard the satellite can be realized quickly, which improves the efficiency and reliability of photogrammetric processing.

Identification of a Discontinuous Parameter in Stochastic Parabolic Systems

International Nuclear Information System (INIS)

Aihara, S. I.

1998-01-01

The purpose of this paper is to study the identification problem for a spatially varying discontinuous parameter in stochastic diffusion equations. The consistency property of the maximum likelihood estimate (M.L.E.) and a generating algorithm for M.L.E. have been explored under the condition that the unknown parameter is in a sufficiently regular space with respect to spatial variables. In order to prove the consistency property of the M.L.E. for a discontinuous diffusion coefficient, we use the method of sieves, i.e., first the admissible class of unknown parameters is projected into a finite-dimensional space and next the convergence of the derived finite-dimensional M.L.E. to the infinite-dimensional M.L.E. is justified under some conditions. An iterative algorithm for generating the M.L.E. is also proposed with two numerical examples

Key parameters analysis of hybrid HEMP simulator

International Nuclear Information System (INIS)

Mao Congguang; Zhou Hui

2009-01-01

According to the new standards on the high-altitude electromagnetic pulse (HEMP) developed by International Electrotechnical Commission (IEC), the target parameter requirements of the key structure of the hybrid HEMP simulator are decomposed. Firstly, the influences of the different excitation sources and biconical structures to the key parameters of the radiated electric field wave shape are investigated and analyzed. Then based on the influence curves the target parameter requirements of the pulse generator are proposed. Finally the appropriate parameters of the biconical structure and the excitation sources are chosen, and the computational result of the electric field in free space is presented. The results are of great value for the design of the hybrid HEMP simulator. (authors)

Operational definition of (brane-induced) space-time and constraints on the fundamental parameters

International Nuclear Information System (INIS)

Maziashvili, Michael

2008-01-01

First we contemplate the operational definition of space-time in four dimensions in light of basic principles of quantum mechanics and general relativity and consider some of its phenomenological consequences. The quantum gravitational fluctuations of the background metric that comes through the operational definition of space-time are controlled by the Planck scale and are therefore strongly suppressed. Then we extend our analysis to the braneworld setup with low fundamental scale of gravity. It is observed that in this case the quantum gravitational fluctuations on the brane may become unacceptably large. The magnification of fluctuations is not linked directly to the low quantum gravity scale but rather to the higher-dimensional modification of Newton's inverse square law at relatively large distances. For models with compact extra dimensions the shape modulus of extra space can be used as a most natural and safe stabilization mechanism against these fluctuations

Planck 2013 results. XVI. Cosmological parameters

DEFF Research Database (Denmark)

Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

2013-01-01

parameters to high precision. We find a low value of the Hubble constant, H0=67.3+/-1.2 km/s/Mpc and a high value of the matter density parameter, Omega_m=0.315+/-0.017 (+/-1 sigma errors) in excellent agreement with constraints from baryon acoustic oscillation (BAO) surveys. Including curvature, we find...... over standard LCDM. The deviation of the scalar spectral index from unity is insensitive to the addition of tensor modes and to changes in the matter content of the Universe. We find a 95% upper limit of r...

Inflation and cosmological parameter estimation

Energy Technology Data Exchange (ETDEWEB)

Hamann, J.

2007-05-15

In this work, we focus on two aspects of cosmological data analysis: inference of parameter values and the search for new effects in the inflationary sector. Constraints on cosmological parameters are commonly derived under the assumption of a minimal model. We point out that this procedure systematically underestimates errors and possibly biases estimates, due to overly restrictive assumptions. In a more conservative approach, we analyse cosmological data using a more general eleven-parameter model. We find that regions of the parameter space that were previously thought ruled out are still compatible with the data; the bounds on individual parameters are relaxed by up to a factor of two, compared to the results for the minimal six-parameter model. Moreover, we analyse a class of inflation models, in which the slow roll conditions are briefly violated, due to a step in the potential. We show that the presence of a step generically leads to an oscillating spectrum and perform a fit to CMB and galaxy clustering data. We do not find conclusive evidence for a step in the potential and derive strong bounds on quantities that parameterise the step. (orig.)

Robotic Fish Technology and Its Applications to Space Mechatronics

OpenAIRE

Yamamoto, Ikuo; Shin, Nobuhiro; Oka, Taishi; Matsui, Miki

2014-01-01

The authors have developed a shark ray robotic fish based on biomimetic approaches. The paper describes the newly developed robotic fish technology and its application to mechatronics in the space. It is found that robotic fish technology creates not only new underwater robotics, but also the next generation space mechatronics for geological survey of lunar/planets and dust cleaning in the space station.

Quantitative analysis of spatial variability of geotechnical parameters

Science.gov (United States)

Fang, Xing

2018-04-01

Geotechnical parameters are the basic parameters of geotechnical engineering design, while the geotechnical parameters have strong regional characteristics. At the same time, the spatial variability of geotechnical parameters has been recognized. It is gradually introduced into the reliability analysis of geotechnical engineering. Based on the statistical theory of geostatistical spatial information, the spatial variability of geotechnical parameters is quantitatively analyzed. At the same time, the evaluation of geotechnical parameters and the correlation coefficient between geotechnical parameters are calculated. A residential district of Tianjin Survey Institute was selected as the research object. There are 68 boreholes in this area and 9 layers of mechanical stratification. The parameters are water content, natural gravity, void ratio, liquid limit, plasticity index, liquidity index, compressibility coefficient, compressive modulus, internal friction angle, cohesion and SP index. According to the principle of statistical correlation, the correlation coefficient of geotechnical parameters is calculated. According to the correlation coefficient, the law of geotechnical parameters is obtained.

Space-Charge Effect

International Nuclear Information System (INIS)

Chauvin, N

2013-01-01

First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented. (author)

Space-Charge Effect

CERN Document Server

Chauvin, N.

2013-12-16

First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented.

Visual exploration of parameter influence on phylogenetic trees.

Science.gov (United States)

Hess, Martin; Bremm, Sebastian; Weissgraeber, Stephanie; Hamacher, Kay; Goesele, Michael; Wiemeyer, Josef; von Landesberger, Tatiana

2014-01-01

Evolutionary relationships between organisms are frequently derived as phylogenetic trees inferred from multiple sequence alignments (MSAs). The MSA parameter space is exponentially large, so tens of thousands of potential trees can emerge for each dataset. A proposed visual-analytics approach can reveal the parameters' impact on the trees. Given input trees created with different parameter settings, it hierarchically clusters the trees according to their structural similarity. The most important clusters of similar trees are shown together with their parameters. This view offers interactive parameter exploration and automatic identification of relevant parameters. Biologists applied this approach to real data of 16S ribosomal RNA and protein sequences of ion channels. It revealed which parameters affected the tree structures. This led to a more reliable selection of the best trees.

Dimensional regularization in configuration space

International Nuclear Information System (INIS)

Bollini, C.G.; Giambiagi, J.J.

1995-09-01

Dimensional regularization is introduced in configuration space by Fourier transforming in D-dimensions the perturbative momentum space Green functions. For this transformation, Bochner theorem is used, no extra parameters, such as those of Feynman or Bogoliubov-Shirkov are needed for convolutions. The regularized causal functions in x-space have ν-dependent moderated singularities at the origin. They can be multiplied together and Fourier transformed (Bochner) without divergence problems. The usual ultraviolet divergences appear as poles of the resultant functions of ν. Several example are discussed. (author). 9 refs

Investigating the Influence of Light Shelf Geometry Parameters on Daylight Performance and Visual Comfort, a Case Study of Educational Space in Tehran, Iran

Directory of Open Access Journals (Sweden)

Mohammad Hossein Moazzeni

2016-07-01

Full Text Available Daylight can be considered as one of the most important principles of sustainable architecture. It is unfortunate that this is neglected by designers in Tehran, a city that benefits from a significant amount of daylight and many clear sunny days during the year. Using a daylight controller system increases space natural light quality and decreases building lighting consumption by 60%. It also affects building thermal behavior, because most of them operate as shading. The light shelf is one of the passive systems for controlling daylight, mostly used with shading and installed in the upper half of the windows above eye level. The influence of light shelf parameters, such as its dimensions, shelf rotation angle and orientation on daylight efficiency and visual comfort in educational spaces is investigated in this article. Daylight simulation software and annual analysis based on climate information during space occupation hours were used. The results show that light shelf dimensions, as well as different orientations, especially in southern part, are influential in the distribution of natural light and visual comfort. At the southern orientation, increased light shelf dimensions result in an increase of the area of the work plane with suitable daylight levels by 2%–40% and a significant decrease in disturbing and intolerable glare hours.

The method of moments and nested Hilbert spaces in quantum mechanics

International Nuclear Information System (INIS)

Adeniyi Bangudu, E.

1980-08-01

It is shown how the structures of a nested Hilbert space Hsub(I), associated with a given Hilbert space Hsub(O), may be used to simplify our understanding of the effects of parameters, whose values have to be chosen rather than determined variationally, in the method of moments. The result, as applied to non-relativistic quartic oscillator and helium atom, is to associate the parameters with sequences of Hilbert spaces, while the error of the method of moments relative to the variational method corresponds to a nesting operator of the nested Hilbert space. Difficulties hindering similar interpretations in terms of rigged Hilbert space structures are highlighted. (author)

Comparison of sampling techniques for Bayesian parameter estimation

Science.gov (United States)

Allison, Rupert; Dunkley, Joanna

2014-02-01

The posterior probability distribution for a set of model parameters encodes all that the data have to tell us in the context of a given model; it is the fundamental quantity for Bayesian parameter estimation. In order to infer the posterior probability distribution we have to decide how to explore parameter space. Here we compare three prescriptions for how parameter space is navigated, discussing their relative merits. We consider Metropolis-Hasting sampling, nested sampling and affine-invariant ensemble Markov chain Monte Carlo (MCMC) sampling. We focus on their performance on toy-model Gaussian likelihoods and on a real-world cosmological data set. We outline the sampling algorithms themselves and elaborate on performance diagnostics such as convergence time, scope for parallelization, dimensional scaling, requisite tunings and suitability for non-Gaussian distributions. We find that nested sampling delivers high-fidelity estimates for posterior statistics at low computational cost, and should be adopted in favour of Metropolis-Hastings in many cases. Affine-invariant MCMC is competitive when computing clusters can be utilized for massive parallelization. Affine-invariant MCMC and existing extensions to nested sampling naturally probe multimodal and curving distributions.

Photosynthesis–irradiance parameters of marine phytoplankton: synthesis of a global data set

OpenAIRE

Bouman, HA; Platt, T; Doblin, M; Figueiras, FG; Gudmundsson, K; Gudfinnsson, HG; Huang, B; Hickman, A; Hiscock, M; Jackson, T; Lutz, VA; Melin, F; Rey, F; Pepin, P; Segura, V

2018-01-01

The photosynthetic performance of marine phytoplankton varies in response to a variety of factors, environmental and taxonomic. One of the aims of the MArine primary Production: model Parameters from Space (MAPPS) project of the European Space Agency is to assemble a global database of photosynthesis–irradiance (P-E) parameters from a range of oceanographic regimes as an aid to examining the basin-scale variability in the photophysiological response of marine phytoplankto...

International Conference on Function Spaces and Inequalities

CERN Document Server

Schmeisser, Hans-Jürgen

2017-01-01

This book features original research and survey articles on the topics of function spaces and inequalities. It focuses on (variable/grand/small) Lebesgue spaces, Orlicz spaces, Lorentz spaces, and Morrey spaces and deals with mapping properties of operators, (weighted) inequalities, pointwise multipliers and interpolation. Moreover, it considers Sobolev–Besov and Triebel–Lizorkin type smoothness spaces. The book includes papers by leading international researchers, presented at the International Conference on Function Spaces and Inequalities, held at the South Asian University, New Delhi, India, on 11–15 December 2015, which focused on recent developments in the theory of spaces with variable exponents. It also offers further investigations concerning Sobolev-type embeddings, discrete inequalities and harmonic analysis. Each chapter is dedicated to a specific topic and written by leading experts, providing an overview of the subject and stimulating future research.

PARAMETER COORDINATION AND ROBUST OPTIMIZATION FOR MULTIDISCIPLINARY DESIGN

Institute of Scientific and Technical Information of China (English)

HU Jie; PENG Yinghong; XIONG Guangleng

2006-01-01

A new parameter coordination and robust optimization approach for multidisciplinary design is presented. Firstly, the constraints network model is established to support engineering change, coordination and optimization. In this model, interval boxes are adopted to describe the uncertainty of design parameters quantitatively to enhance the design robustness. Secondly, the parameter coordination method is presented to solve the constraints network model, monitor the potential conflicts due to engineering changes, and obtain the consistency solution space corresponding to the given product specifications. Finally, the robust parameter optimization model is established, and genetic arithmetic is used to obtain the robust optimization parameter. An example of bogie design is analyzed to show the scheme to be effective.

Space research in the Netherlands 1980

International Nuclear Information System (INIS)

1981-01-01

In 1960, the Royal Netherlands Academy of Arts and Sciences established a committee with the task of coordinating space research in the Netherlands and maintaining the necessary international contacts. This committe, usually called GROC, has instituted four working groups, in which most of the Netherlands space research is concentrated. These groups are: Working Group for Solar and Stellar Space Research, Working Group for Cosmic Rays, Working Group for Photometry and the Working Group for Satellite Geodesy. General information on space research in the Netherlands Anno 1980 is given. Detailed data about the working groups, their work during 1980 and their programmes are presented, together with a survey of their scientific publications. A financial summary is also included. (Auth.)

pypet: A Python Toolkit for Data Management of Parameter Explorations.

Science.gov (United States)

Meyer, Robert; Obermayer, Klaus

2016-01-01

pypet (Python parameter exploration toolkit) is a new multi-platform Python toolkit for managing numerical simulations. Sampling the space of model parameters is a key aspect of simulations and numerical experiments. pypet is designed to allow easy and arbitrary sampling of trajectories through a parameter space beyond simple grid searches. pypet collects and stores both simulation parameters and results in a single HDF5 file. This collective storage allows fast and convenient loading of data for further analyses. pypet provides various additional features such as multiprocessing and parallelization of simulations, dynamic loading of data, integration of git version control, and supervision of experiments via the electronic lab notebook Sumatra. pypet supports a rich set of data formats, including native Python types, Numpy and Scipy data, Pandas DataFrames, and BRIAN(2) quantities. Besides these formats, users can easily extend the toolkit to allow customized data types. pypet is a flexible tool suited for both short Python scripts and large scale projects. pypet's various features, especially the tight link between parameters and results, promote reproducible research in computational neuroscience and simulation-based disciplines.

Efficient classification of complete parameter regions based on semidefinite programming

Directory of Open Access Journals (Sweden)

Parrilo Pablo A

2007-01-01

Full Text Available Abstract Background Current approaches to parameter estimation are often inappropriate or inconvenient for the modelling of complex biological systems. For systems described by nonlinear equations, the conventional approach is to first numerically integrate the model, and then, in a second a posteriori step, check for consistency with experimental constraints. Hence, only single parameter sets can be considered at a time. Consequently, it is impossible to conclude that the "best" solution was identified or that no good solution exists, because parameter spaces typically cannot be explored in a reasonable amount of time. Results We introduce a novel approach based on semidefinite programming to directly identify consistent steady state concentrations for systems consisting of mass action kinetics, i.e., polynomial equations and inequality constraints. The duality properties of semidefinite programming allow to rigorously certify infeasibility for whole regions of parameter space, thus enabling the simultaneous multi-dimensional analysis of entire parameter sets. Conclusion Our algorithm reduces the computational effort of parameter estimation by several orders of magnitude, as illustrated through conceptual sample problems. Of particular relevance for systems biology, the approach can discriminate between structurally different candidate models by proving inconsistency with the available data.

Long-term integrated radiophysical studies of the ionosphere, near space, and the propagation of radio waves from space objects

Science.gov (United States)

Misyura, V. A.

1974-01-01

The radiophysical studies reported consist of direct measurements of certain effects induced in the propagation of radio waves from space objects. From measured effects and from data on the motion and position of space objects, physical parameters of the medium and bodies are determined.

Space Microbiology

Science.gov (United States)

Horneck, Gerda; Klaus, David M.; Mancinelli, Rocco L.

2010-01-01

Summary: The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis. PMID:20197502

Transiting Exoplanet Survey Satellite (TESS)

Science.gov (United States)

Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

2012-01-01

The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

Space weather and space anomalies

Directory of Open Access Journals (Sweden)

L. I. Dorman

2005-11-01

Full Text Available A large database of anomalies, registered by 220 satellites in different orbits over the period 1971-1994 has been compiled. For the first time, data from 49 Russian Kosmos satellites have been included in a statistical analysis. The database also contains a large set of daily and hourly space weather parameters. A series of statistical analyses made it possible to quantify, for different satellite orbits, space weather conditions on the days characterized by anomaly occurrences. In particular, very intense fluxes (>1000 pfu at energy >10 MeV of solar protons are linked to anomalies registered by satellites in high-altitude (>15000 km, near-polar (inclination >55° orbits typical for navigation satellites, such as those used in the GPS network, NAVSTAR, etc. (the rate of anomalies increases by a factor ~20, and to a much smaller extent to anomalies in geostationary orbits, (they increase by a factor ~4. Direct and indirect connections between anomaly occurrence and geomagnetic perturbations are also discussed.

Constraining the loop quantum gravity parameter space from phenomenology

Science.gov (United States)

Brahma, Suddhasattwa; Ronco, Michele

2018-03-01

Development of quantum gravity theories rarely takes inputs from experimental physics. In this letter, we take a small step towards correcting this by establishing a paradigm for incorporating putative quantum corrections, arising from canonical quantum gravity (QG) theories, in deriving falsifiable modified dispersion relations (MDRs) for particles on a deformed Minkowski space-time. This allows us to differentiate and, hopefully, pick between several quantization choices via testable, state-of-the-art phenomenological predictions. Although a few explicit examples from loop quantum gravity (LQG) (such as the regularization scheme used or the representation of the gauge group) are shown here to establish the claim, our framework is more general and is capable of addressing other quantization ambiguities within LQG and also those arising from other similar QG approaches.

Using spaced education to teach interns about teaching skills.

Science.gov (United States)

Pernar, Luise I M; Corso, Katherine; Lipsitz, Stuart R; Breen, Elizabeth

2013-07-01

Despite limited preparation and knowledge base, surgical interns have important teaching responsibilities. Nevertheless, few faculty development programs are aimed at interns. Succinct teaching skill content was electronically distributed over time (spaced education) to interns in academic year 2010/2011. The interns in the previous year served as historic controls. Electronic surveys were distributed for program evaluation. Fifteen of 24 (62.5%) interns and 35 of 49 (71.4%) students responded to the surveys in academic year 2009/2010 and 16 of 27 (59.3%) interns and 38 of 52 (73%) students responded in academic year 2010/2011. Surveys showed improved attitudes toward teaching by interns as well as a higher estimation of interns' teaching skills as rated by students for those interns who received the spaced education program. Using spaced education to improve interns' teaching skills is a potentially powerful intervention that improves interns' enthusiasm for teaching and teaching effectiveness. The changes are mirrored in students' ratings of interns' teaching skills and interns' attitudes toward teaching. Copyright © 2013 Elsevier Inc. All rights reserved.

The Hubble Space Telescope Medium Deep Survey Cluster Sample: Methodology and Data

Science.gov (United States)

Ostrander, E. J.; Nichol, R. C.; Ratnatunga, K. U.; Griffiths, R. E.

1998-12-01

We present a new, objectively selected, sample of galaxy overdensities detected in the Hubble Space Telescope Medium Deep Survey (MDS). These clusters/groups were found using an automated procedure that involved searching for statistically significant galaxy overdensities. The contrast of the clusters against the field galaxy population is increased when morphological data are used to search around bulge-dominated galaxies. In total, we present 92 overdensities above a probability threshold of 99.5%. We show, via extensive Monte Carlo simulations, that at least 60% of these overdensities are likely to be real clusters and groups and not random line-of-sight superpositions of galaxies. For each overdensity in the MDS cluster sample, we provide a richness and the average of the bulge-to-total ratio of galaxies within each system. This MDS cluster sample potentially contains some of the most distant clusters/groups ever detected, with about 25% of the overdensities having estimated redshifts z > ~0.9. We have made this sample publicly available to facilitate spectroscopic confirmation of these clusters and help more detailed studies of cluster and galaxy evolution. We also report the serendipitous discovery of a new cluster close on the sky to the rich optical cluster Cl l0016+16 at z = 0.546. This new overdensity, HST 001831+16208, may be coincident with both an X-ray source and a radio source. HST 001831+16208 is the third cluster/group discovered near to Cl 0016+16 and appears to strengthen the claims of Connolly et al. of superclustering at high redshift.

Solubility-Parameter-Guided Solvent Selection to Initiate Ostwald Ripening for Interior Space-Tunable Structures with Architecture-Dependent Electrochemical Performance.

Science.gov (United States)

Mao, Baoguang; Guo, Donglei; Qin, Jinwen; Meng, Tao; Wang, Xin; Cao, Minhua

2018-01-08

Despite significant advancement in preparing various hollow structures by Ostwald ripening, one common problem is the intractable uncontrollability of initiating Ostwald ripening due to the complexity of the reaction processes. Here, a new strategy on Hansen solubility parameter (HSP)-guided solvent selection to initiate Ostwald ripening is proposed. Based on this comprehensive principle for solvent optimization, N,N-dimethylformamide (DMF) was screened out, achieving accurate synthesis of interior space-tunable MoSe 2 spherical structures (solid, core-shell, yolk-shell and hollow spheres). The resultant MoSe 2 structures exhibit architecture-dependent electrochemical performances towards hydrogen evolution reaction and sodium-ion batteries. This pre-solvent selection strategy can effectively provide researchers great possibility in efficiently synthesizing various hollow structures. This work paves a new pathway for deeply understanding Ostwald ripening. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Topological vector spaces and their applications

CERN Document Server

Bogachev, V I

2017-01-01

This book gives a compact exposition of the fundamentals of the theory of locally convex topological vector spaces. Furthermore it contains a survey of the most important results of a more subtle nature, which cannot be regarded as basic, but knowledge which is useful for understanding applications. Finally, the book explores some of such applications connected with differential calculus and measure theory in infinite-dimensional spaces. These applications are a central aspect of the book, which is why it is different from the wide range of existing texts on topological vector spaces. In addition, this book develops differential and integral calculus on infinite-dimensional locally convex spaces by using methods and techniques of the theory of locally convex spaces. The target readership includes mathematicians and physicists whose research is related to infinite-dimensional analysis.

Sacred space and the healing journey.

Science.gov (United States)

Alt, Paul L

2017-07-01

Sacred space and spirituality have long been used to heal the mind, body, and spirit. This article illuminates the origins of sacred space and its role as a healing environment from the first human construct, the burial mound, to the 5th Century BCE Greek healing city of Epidaurus. It then examines the role of spirituality as one of the necessary human institutions for a healthy society, according to the Italian philosopher Giambattista Vico. The conclusion then surveys three contemporary healing environments' architecture, the Department of Veteran Affairs Healing Environment Design Guideline (VAHEDG), and how these sacred spaces mend individual and community ailments.

Moving mirrors and black hole evaporation in noncommutative space-times

International Nuclear Information System (INIS)

Casadio, R.; Cox, P.H.; Harms, B.; Micu, O.

2006-01-01

We study the evaporation of black holes in noncommutative space-times. We do this by calculating the correction to the detector's response function for a moving mirror in terms of the noncommutativity parameter Θ and then extracting the number density as modified by this parameter. We find that allowing space and time to be noncommutative increases the decay rate of a black hole

Radiographers' professional knowledge regarding parameters and safety issues in plain radiography: a questionnaire survey.

Science.gov (United States)

Farajollahi, A R; Fouladi, D F; Ghojazadeh, M; Movafaghi, A

2014-08-01

To review the knowledge of radiographers and examine the possible sociodemographic and situational contributors to this knowledge. A questionnaire survey was devised and distributed to a cohort of 120 radiographers. Each questionnaire contained two sections. In the first section, background data, including sex, age, highest academic level, grade point average (GPA), length of time from graduation, work experience as a radiographer and the status of previous refresher course(s), were collected. The second section contained 17 multiple-choice questions concerning radiographic imaging parameters and safety issues. The response rate was 63.8%. In univariate analytic model, higher academic degree (p workplace (p = 0.04) and taking previous refresher course(s) (p = 0.01) were significantly associated with higher knowledge score. In multivariate analytic model, however, higher academic degree (B = 1.62; p = 0.01), higher GPA (B = 0.50; p = 0.01) and taking previous refresher course(s) (B = -1.26; p = 0.03) were independently associated with higher level of knowledge. Age, sex, length of time from graduation and work experience were not associated with the respondents' knowledge score. Academic background is a robust indicator of a radiographer's professional knowledge. Refresher courses and regular knowledge assessments are highly recommended. This is the first study in the literature that examines professional knowledge of radiographers in terms of technical and safety issues in plain radiography. Academic degree, GPA and refresher courses are independent predictors of this knowledge. Regular radiographer professional knowledge checks may be recommended.

Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies

International Nuclear Information System (INIS)

Xie Faxiang; Sun Limin

2010-01-01

The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

Survival of Spores of Trichoderma longibrachiatum in Space: data from the Space Experiment SPORES on EXPOSE-R

Science.gov (United States)

Neuberger, Katja; Lux-Endrich, Astrid; Panitz, Corinna

2015-01-01

In the space experiment `Spores in artificial meteorites' (SPORES), spores of the fungus Trichoderma longibrachiatum were exposed to low-Earth orbit for nearly 2 years on board the EXPOSE-R facility outside of the International Space Station. The environmental conditions tested in space were: space vacuum at 10-7-10-4 Pa or argon atmosphere at 105 Pa as inert gas atmosphere, solar extraterrestrial ultraviolet (UV) radiation at λ > 110 nm or λ > 200 nm with fluences up to 5.8 × 108 J m-2, cosmic radiation of a total dose range from 225 to 320 mGy, and temperature fluctuations from -25 to +50°C, applied isolated or in combination. Comparable control experiments were performed on ground. After retrieval, viability of spores was analysed by two methods: (i) ethidium bromide staining and (ii) test of germination capability. About 30% of the spores in vacuum survived the space travel, if shielded against insolation. However, in most cases no significant decrease was observed for spores exposed in addition to the full spectrum of solar UV irradiation. As the spores were exposed in clusters, the outer layers of spores may have shielded the inner part. The results give some information about the likelihood of lithopanspermia, the natural transfer of micro-organisms between planets. In addition to the parameters of outer space, sojourn time in space seems to be one of the limiting parameters.

Photogrammetry and ballistic analysis of a high-flying projectile in the STS-124 space shuttle launch

Science.gov (United States)

Metzger, Philip T.; Lane, John E.; Carilli, Robert A.; Long, Jason M.; Shawn, Kathy L.

2010-07-01

A method combining photogrammetry with ballistic analysis is demonstrated to identify flying debris in a rocket launch environment. Debris traveling near the STS-124 Space Shuttle was captured on cameras viewing the launch pad within the first few seconds after launch. One particular piece of debris caught the attention of investigators studying the release of flame trench fire bricks because its high trajectory could indicate a flight risk to the Space Shuttle. Digitized images from two pad perimeter high-speed 16-mm film cameras were processed using photogrammetry software based on a multi-parameter optimization technique. Reference points in the image were found from 3D CAD models of the launch pad and from surveyed points on the pad. The three-dimensional reference points were matched to the equivalent two-dimensional camera projections by optimizing the camera model parameters using a gradient search optimization technique. Using this method of solving the triangulation problem, the xyz position of the object's path relative to the reference point coordinate system was found for every set of synchronized images. This trajectory was then compared to a predicted trajectory while performing regression analysis on the ballistic coefficient and other parameters. This identified, with a high degree of confidence, the object's material density and thus its probable origin within the launch pad environment. Future extensions of this methodology may make it possible to diagnose the underlying causes of debris-releasing events in near-real time, thus improving flight safety.

Aerial radiological survey of the Argonne National Laboratory and surrounding area, Argonne, Illinois. Date of survey: May 1977

International Nuclear Information System (INIS)

1982-12-01

An aerial radiological survey was conducted over the facilities of the Argonne National Laboratory in Argonne, Illinois, on 2 to 13 May 1977. The survey was flown at an altitude of 46 m by a helicopter containing 20 sodium iodide detectors. The line spacing was also 46 m. Enhanced gamma exposure rate levels, which could be attributed to Argonne operations, were observed at many locations

PHYSICAL PARAMETERS OF ASTEROIDS ESTIMATED FROM THE WISE 3-BAND DATA AND NEOWISE POST-CRYOGENIC SURVEY

Energy Technology Data Exchange (ETDEWEB)

Mainzer, A.; Masiero, J.; Bauer, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ 85719 (United States); Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); McMillan, R. S. [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721-0092 (United States); Nugent, C. R. [Department of Earth and Space Sciences, UCLA, 595 Charles Young Drive East, Box 951567, Los Angeles, CA 90095-1567 (United States); Tholen, D. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Walker, R. [Monterey Institute for Research in Astronomy, Monterey, CA 93933 (United States); Wright, E. L., E-mail: amainzer@jpl.nasa.gov [Department of Physics and Astronomy, UCLA, P.O. Box 91547, Los Angeles, CA 90095-1547 (United States)

2012-11-20

Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Survey Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of >158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four-month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of {approx}6500 large Main Belt asteroids and 86 NEOs in its 3.4 and 4.6 {mu}m channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.

Constraining primordial non-Gaussianity with bispectrum and power spectrum from upcoming optical and radio surveys

Science.gov (United States)

Karagiannis, Dionysios; Lazanu, Andrei; Liguori, Michele; Raccanelli, Alvise; Bartolo, Nicola; Verde, Licia

2018-07-01

We forecast constraints on primordial non-Gaussianity (PNG) and bias parameters from measurements of galaxy power spectrum and bispectrum in future radio continuum and optical surveys. In the galaxy bispectrum, we consider a comprehensive list of effects, including the bias expansion for non-Gaussian initial conditions up to second order, redshift space distortions, redshift uncertainties and theoretical errors. These effects are all combined in a single PNG forecast for the first time. Moreover, we improve the bispectrum modelling over previous forecasts, by accounting for trispectrum contributions. All effects have an impact on final predicted bounds, which varies with the type of survey. We find that the bispectrum can lead to improvements up to a factor ˜5 over bounds based on the power spectrum alone, leading to significantly better constraints for local-type PNG, with respect to current limits from Planck. Future radio and photometric surveys could obtain a measurement error of σ (f_{NL}^{loc}) ≈ 0.2. In the case of equilateral PNG, galaxy bispectrum can improve upon present bounds only if significant improvements in the redshift determinations of future, large volume, photometric or radio surveys could be achieved. For orthogonal non-Gaussianity, expected constraints are generally comparable to current ones.

Constraining Primordial non-Gaussianity with Bispectrum and Power Spectum from Upcoming Optical and Radio Surveys

Science.gov (United States)

Karagiannis, Dionysios; Lazanu, Andrei; Liguori, Michele; Raccanelli, Alvise; Bartolo, Nicola; Verde, Licia

2018-04-01

We forecast constraints on primordial non-Gaussianity (PNG) and bias parameters from measurements of galaxy power spectrum and bispectrum in future radio continuum and optical surveys. In the galaxy bispectrum, we consider a comprehensive list of effects, including the bias expansion for non-Gaussian initial conditions up to second order, redshift space distortions, redshift uncertainties and theoretical errors. These effects are all combined in a single PNG forecast for the first time. Moreover, we improve the bispectrum modelling over previous forecasts, by accounting for trispectrum contributions. All effects have an impact on final predicted bounds, which varies with the type of survey. We find that the bispectrum can lead to improvements up to a factor ˜5 over bounds based on the power spectrum alone, leading to significantly better constraints for local-type PNG, with respect to current limits from Planck. Future radio and photometric surveys could obtain a measurement error of σ (f_{NL}^{loc}) ≈ 0.2. In the case of equilateral PNG, galaxy bispectrum can improve upon present bounds only if significant improvements in the redshift determinations of future, large volume, photometric or radio surveys could be achieved. For orthogonal non-Gaussianity, expected constraints are generally comparable to current ones.

The Galaxy Count Correlation Function in Redshift Space Revisited

Science.gov (United States)

Campagne, J.-E.; Plaszczynski, S.; Neveu, J.

2017-08-01

In the near future, cosmology will enter the wide and deep galaxy survey era, enabling high-precision studies of the large-scale structure of the universe in three dimensions. To test cosmological models and determine their parameters accurately, it is necessary to use data with exact theoretical expectations expressed in observational parameter space (angles and redshift). The data-driven, galaxy number count fluctuations on redshift shells can be used to build correlation functions ξ (θ ,{z}1,{z}2) on and between shells to probe the baryonic acoustic oscillations and distance-redshift distortions, as well as gravitational lensing and other relativistic effects. To obtain a numerical estimation of ξ (θ ,{z}1,{z}2) from a cosmological model, it is typical to use either a closed form derived from a tripolar spherical expansion or to compute the power spectrum {C}{\\ell }({z}1,{z}2) and perform a Legendre polynomial {P}{\\ell }(\\cos θ ) expansion. Here, we present a new derivation of a ξ (θ ,{z}1,{z}2) closed form using the spherical harmonic expansion and proceeding to an infinite sum over multipoles thanks to an addition theorem. We demonstrate that this new expression is perfectly compatible with the existing closed forms but is simpler to establish and manipulate. We provide formulas for the leading density and redshift-space contributions, but also show how Doppler-like and lensing terms can be easily included in this formalism. We have implemented and made publicly available software for computing those correlations efficiently, without any Limber approximation, and validated this software with the CLASSgal code. It is available at https://gitlab.in2p3.fr/campagne/AngPow.

AI in space: Past, present, and possible futures

Science.gov (United States)

Rose, Donald D.; Post, Jonathan V.

1992-01-01

While artificial intelligence (AI) has become increasingly present in recent space applications, new missions being planned will require even more incorporation of AI techniques. In this paper, we survey some of the progress made to date in implementing such programs, some current directions and issues, and speculate about the future of AI in space scenarios. We also provide examples of how thinkers from the realm of science fiction have envisioned AI's role in various aspects of space exploration.