Articles de revues : « Distributions of possibilities »

1

Söderström, S. « Possibilities and limitations of non-homogeneous dose distributions ». European Journal of Cancer 29 (janvier 1993) : S28. http://dx.doi.org/10.1016/0959-8049(93)90746-3.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

2

Polosin, Vitaly. « Mapping of Beta Distribution for the Study of Dispersed Materials ». Materials Science Forum 1049 (11 janvier 2022) : 295–304. http://dx.doi.org/10.4028/www.scientific.net/msf.1049.295.

Texte intégral

Résumé :

In the study of polydisperse materials, most of the experimental particle size distributions were obtained on bounded intervals. In these cases, it is also desirable to use bounded models with different shapes to simulate the results of studying polydisperse and powder materials. The beta distribution is often used to approximate results due to the fact that this distribution contains many forms for displaying realizations on a limited interval. With the development of computer technology, there has been an increased interest in the use of beta distribution in the modern practice of analyzing results. Meanwhile, there remains a limitation in the use of the beta distribution that is associated with the choice of distribution shape. The possibilities of using known shape measures for mapping beta distribution in this paper is discusses. On the example of the space of shape measure of kurtosis and skewness, the limited use of only probabilistic measures of shapes is illustrated. It is proposed to use the entropy coefficients as an additional informational parameter of the beta distribution shape. On the base of a features comparison of the entropy coefficients for biased and unbiased beta distributions, recommendations for their application are given. By using the example of beta distributions mapping in the space of asymmetry and the entropy coefficient, it is shown that the synergistic combination of probabilistic and informational measures of the shape allows expanding the possibilities of estimating the shape parameters beta distributions. Two methods to display the positions of realizations of beta distributions is proposed. There are trajectories on a constant ratio of shape and realizations position curve on equal values of one parameter. In particular, the features of the choice of beta distributions with negative skewness are discussed.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Lotov, Vladimir Ivanovich. « Exact formulas in some boundary crossing problems for integer-valued random walks ». Izvestiya : Mathematics 87, n^o 1 (2023) : 45–60. http://dx.doi.org/10.4213/im9323e.

Texte intégral

Résumé :

For a wide class of integer-valued random walks, we obtain exact expressions for the distribution of the first excess over level and the corresponding renewal function as well as for the distribution of the trajectory supremum if it is finite. We discuss possibilities of obtaining explicit expressions for pre-stationary and stationary distributions of a random walk with switchings at the strip boundaries. The research is based on the factorization representations for the double moment generating functions of the distributions under study.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Tomy, Lishamol, et Gokul Satish. « A review study on trigonometric transformations of statistical distributions ». Biometrics & ; Biostatistics International Journal 10, n^o 4 (13 octobre 2021) : 130–36. http://dx.doi.org/10.15406/bbij.2021.10.00339.

Texte intégral

Résumé :

For the past few years, various forms of statistical distributions based on trigonometrical transformation were proposed by researchers to model data and thereby finding the suitable distribution to predict the possibilities, and application of it in real life. This article aims to review the recent developments and contributions brought about by the various families of trigonometric functions in statistical distribution and its application in data modelling. Several generalised trigonometric distributions are reviewed and compared along with their properties and uses.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Antonuyk, Olha, et Alexandr Ushenko. « Possibilities of laser polarimetric diagnostics of umbilical blood and capillary maternal blood ». Natural & ; Mathematical Sciences in Medicine and Medical Education 1, n^o 1 (27 décembre 2024) : 22–29. https://doi.org/10.24061/3083-5887.j.nmsmme.2024.1.i.2.

Texte intégral

Résumé :

A comparative analysis of the two types of samples showed differences in values of the statistical moments of the 3rd and 4th orders. In particular, the statistical moment of the 3rd order (asymmetry) is 2.5 times greater and the 4th parameter (kurtosis) is 2.5 times greater for the blood samples of newborns without pathological changes than the similar parameter for the blood samples of newborns with pathological changes. Fractal analysis showed the transformation of the distribution of power spectra from fractal for coordinate distributions of the Muller matrix element for blood samples without pathology to multifractal (fractal dimensions D1=1.66, D2= 2.90 and D3= 0.56) of blood samples with pathology. The diagnostic sensitivity of the statistical moments of the coordinate distributions of the orientation-phase elements of the Muller p34 matrix of higher orders (3rd and 4th) to structural changes occurring in blood samples of mothers of newborns with a normal physiological state and with pathological changes was revealed. In particular, with pathological changes, the statistical moments of the third order (asymmetry) decrease by 3.5 times, and accordingly, the statistical moment of the fourth order (kurtosis) increases by 2.5 times. The spread of the values of the statistical moments within the two groups did not exceed 5-10% of corresponding average values. The diagnostic possibilities of statistical and fractal analysis of the coordinate distributions of the elements of the Mueller matrix of blood samples of different physiological states of newborns and their mothers have been demonstrated. Fractal and statistical analysis of the coordinate distributions of the orientational elements of the Mueller matrix p33 are diagnostically sensitive when examining the blood of newborns. For maternal blood samples, the statistical analysis of the orientational-phase elements of the Muller p34 matrix (increase in the statistical moments of the 3rd and 4th orders with pathological changes) is diagnostically sensitive.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Rumyantseva, Olga D., Andrey S. Shurup et Dmitriy I. Zotov. « Possibilities for separation of scalar and vector characteristics of acoustic scatterer in tomographic polychromatic regime ». Journal of Inverse and Ill-posed Problems 29, n^o 3 (16 janvier 2021) : 407–20. http://dx.doi.org/10.1515/jiip-2020-0141.

Texte intégral

Résumé :

Abstract The inverse wave problem of tomographic type is considered. It consists in reconstruction of several scatterer’s characteristics in the form of spatial distributions for sound speed, medium density, absorption coefficient and power index of its frequency dependence, as well as vector of flow velocity. In the form of a survey material (based on several publications), a sequence of steps is discussed that leads to reconstruction of each individual spatial distribution in the presence of different combinations of the mentioned characteristics. The minimum number of frequencies required for reconstruction is discussed when the complete set of scattering data is available at each of the frequencies. For the first time, two possible approaches to reconstruct the scatterer characteristics in the presence of inhomogeneous spatial distributions of the density and the flow velocity vector are compared, and attention is drawn to the perspectives of reconstruction by functional algorithms in this case. The possibility of separating the sought spatial distributions during the inverse problem solution is illustrated by numerical modeling.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Sauerbrei, Sonja, Uwe Sydow et Peter J. Plath. « On the Characterization of Foam Decay with Diagram Lattices and Majorization ». Zeitschrift für Naturforschung A 61, n^o 3-4 (1 avril 2006) : 153–65. http://dx.doi.org/10.1515/zna-2006-3-408.

Texte intégral

Résumé :

We present possibilities of comparing and characterizing bubble size distributions during foam decay. We know that the temporal development of bubble size distributions does not follow an ordinary diffusion process. Instead of an equal distribution, we obtain a multi-modal distribution at the end of the rearrangement phase. It turns out that bubble size distributions are comparable to partition diagrams generating Ruch lattices which are expandable by permutations leading to partially ordered sets. If we map the partition diagrams and the bubble size distributions on the Shannon entropy, we obtain similar functions. Furthermore, the set of partition diagrams of a Ruch lattice and the set of the bubble size distributions of foam decay are both partially ordered. Via the theorems of Muirhead and of Hardy, Littlewood and Pólya (classical majorization) we construct transitions between every partition diagram of a Ruch lattice and between every bubble size distribution. These transitions can be reversible or irreversible

Styles APA, Harvard, Vancouver, ISO, etc.

8

Astola, Jaakko, et Eduard Danielian. « Dediscretization of distributions arising in macroevolution models ». Facta universitatis - series : Electronics and Energetics 20, n^o 2 (2007) : 119–46. http://dx.doi.org/10.2298/fuee0702119a.

Texte intégral

Résumé :

The standard birth-death process with intensities of moderate growth generates stationary skewed distributions suitable for modeling frequency distributions of events arising in large-scale biomolecular systems. We study a large class of such distributions that can be used to model, for instance frequency distributions of the number of expressed genes in the transcriptome, the number of protein domain occurrences in the proteomes etc. In the present paper a new dediscretization approach is suggested discussed and applied to the chosen class. This approach conserves the qualitative properties of the original class of distributions. The advantages of the approach consist in following: 1. It simplifies the form of distributions; 2. It allows simple mathematical analysis of the properties of the original class by applying the tools mathematical analysis continuous functions 3. It allows to find out the optimal form of stationary distributions, i.e. suggests new classes of distributions for biomolecular applications. The deviations of the dediscretized continuous distribution functions from the original distribution functions is estimated. Several typical examples are considered which illustrate the possibilities of the dediscretization approach. The reverse procedure to dediscretization, i.e. the procedure of discretization, back to discrete distributions is described.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Tomanová, Dagmar, et Petr Schneider. « Possibilities of determining the polymodal pore-size distribution from physical adsorption of nitrogen ». Collection of Czechoslovak Chemical Communications 52, n^o 5 (1987) : 1160–66. http://dx.doi.org/10.1135/cccc19871160.

Texte intégral

Résumé :

It is shown, on the basis of experimentally determined adsorption isotherms of physical adsorption of nitrogen on two- and three-component mixtures of fine grained porous glasses with narrow pore-size distributions, that the polymodal mesopore-size distribution curves can be evaluated in case that the porous sample contains groups of mesopores differing rather significantly in size. The differentiation of groups of pores gets worse with wider pores where the demands on the accuracy of the relative pressure measurement grow stronger.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Kollo, Tõnu, Meelis Käärik et Anne Selart. « Multivariate Skew t-Distribution : Asymptotics for Parameter Estimators and Extension to Skew t-Copula ». Symmetry 13, n^o 6 (11 juin 2021) : 1059. http://dx.doi.org/10.3390/sym13061059.

Texte intégral

Résumé :

Symmetric elliptical distributions have been intensively used in data modeling and robustness studies. The area of applications was considerably widened after transforming elliptical distributions into the skew elliptical ones that preserve several good properties of the corresponding symmetric distributions and increase possibilities of data modeling. We consider three-parameter p-variate skew t-distribution where p-vector μ is the location parameter, Σ:p×p is the positive definite scale parameter, p-vector α is the skewness or shape parameter, and the number of degrees of freedom ν is fixed. Special attention is paid to the two-parameter distribution when μ=0 that is useful for construction of the skew t-copula. Expressions of the parameters are presented through the moments and parameter estimates are found by the method of moments. Asymptotic normality is established for the estimators of Σ and α. Convergence to the asymptotic distributions is examined in simulation experiments.

Styles APA, Harvard, Vancouver, ISO, etc.

11

MYRONYUK, MARGARYTA. « HEYDE’S CHARACTERIZATION THEOREM FOR DISCRETE ABELIAN GROUPS ». Journal of the Australian Mathematical Society 88, n^o 1 (22 janvier 2010) : 93–102. http://dx.doi.org/10.1017/s1446788709000378.

Texte intégral

Résumé :

AbstractLet X be a countable discrete abelian group with automorphism group Aut(X). Let ξ1 and ξ2 be independent X-valued random variables with distributions μ1 and μ2, respectively. Suppose that α1,α2,β1,β2∈Aut(X) and β1α−11±β2α−12∈Aut(X). Assuming that the conditional distribution of the linear form L2 given L1 is symmetric, where L2=β1ξ1+β2ξ2 and L1=α1ξ1+α2ξ2, we describe all possibilities for the μj. This is a group-theoretic analogue of Heyde’s characterization of Gaussian distributions on the real line.

Styles APA, Harvard, Vancouver, ISO, etc.

12

BENGUIGUI, LUCIEN, et EFRAT BLUMENFELD-LIEBERTHAL. « FROM LOGNORMAL DISTRIBUTION TO POWER LAW : A NEW CLASSIFICATION OF THE SIZE DISTRIBUTIONS ». International Journal of Modern Physics C 17, n^o 10 (octobre 2006) : 1429–36. http://dx.doi.org/10.1142/s0129183106009953.

Texte intégral

Résumé :

We propose a new classification of the size distributions of entities based on an exponent α defined from the shape of the log–log Rank Size plot. From an inspection of a large number of cases in different fields, one finds three possibilities: α = 1 giving a power law, α > 1 (parabola like curve) and 0 < α < 1 (analogous to a log normal distribution). A fourth possibility that can be defined when α < 0 was never observed. We present a modified version of models based on a random multiplicative process and an introduction of new entities during the growth. We recover all three kinds of distributions and show that the type of a distribution is conditioned by the rate of the introduction of new entities.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Kung, Woon-Man, Yao-Chin Wang, Wei-Jung Chen et Muh-Shi Lin. « Homogeneous Chronic Subdural Hematoma with Diverse Recurrent Possibilities ». Diagnostics 12, n^o 11 (4 novembre 2022) : 2695. http://dx.doi.org/10.3390/diagnostics12112695.

Texte intégral

Résumé :

Background: Evidence suggests that hyperdense (HD) chronic subdural hematomas (CSDHs) have a higher recurrence than hypodense (LD) chronic subdural hematomas. The value of mean hematoma density (MHD) has been proven to be associated with postoperative recurrence. The MHD levels in homogeneous CSDHs likely underestimate the risk of recurrence in HD homogeneous subtypes. Methods: This study investigated 42 consecutive CSDH cases between July 2010 and July 2014. The area of the hematoma was quantified to determine the MHD level using computer-based image analysis of preoperative brain CT scans. Results: In terms of the MHD distribution of the four types of CSDHs (homogeneous, laminar, separated, and trabecular), wide 95% CI (11.80–16.88) and high standard deviation (4.59) can be found in homogeneous types, reflecting a high variability in the MHD levels between cases (from low to high density). The categorization of homogeneous types into LD and HD (type five) displayed a minor standard deviation in the MHD levels for LD and HD subtypes (1.15, and 0.88, respectively). MHD values demonstrated concentrated distributions among the respective five types, compared to the four-type setting. Conclusions: In the current research, we provide a consideration that if LD and HD hematomas are separated from homogeneous CSDHs, the variability of the MHD quantification can potentially be reduced, thereby avoiding the possibility of undetected high-risk groups.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Ebert, M. A., et P. W. Hoban. « Possibilities for tailoring dose distributions through the manipulation of electron beam characteristics ». Physics in Medicine and Biology 42, n^o 11 (1 novembre 1997) : 2065–81. http://dx.doi.org/10.1088/0031-9155/42/11/005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

15

Wu, Wei-Sheng. « Different Functional Gene Clusters in Yeast have Different Spatial Distributions of the Transcription Factor Binding Sites ». Bioinformatics and Biology Insights 5 (janvier 2011) : BBI.S6362. http://dx.doi.org/10.4137/bbi.s6362.

Texte intégral

Résumé :

Transcription factors control gene expression by binding to short specific DNA sequences, called transcription factor binding sites (TFBSs), in the promoter of a gene. Thus, studying the spatial distribution of TFBSs in the promoters may provide insights into the molecular mechanisms of gene regulation. I developed a method to construct the spatial distribution of TFBSs for any set of genes of interest. I found that different functional gene clusters have different spatial distributions of TFBSs, indicating that gene regulation mechanisms may be very different among different functional gene clusters. I also found that the binding sites for different transcription factors (TFs) may have different spatial distributions: a sharp peak, a plateau or no dominant single peak. The spatial distributions of binding sites for many TFs derived from my analyses are valuable prior information for TFBS prediction algorithm because different regions of a promoter can assign different possibilities for TFBS occurrence.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Берестин, D. Berestin, Попов, Yuriy Popov, Вохмина, Yu Vokhmina, Хадарцева et K. Khadartseva. « Possibilities of stochastic processing of system parameters with chaotic dynamics ». Complexity. Mind. Postnonclassic 3, n^o 2 (21 mai 2014) : 59–67. http://dx.doi.org/10.12737/5519.

Texte intégral

Résumé :

The paper presents the first attempt to combine methods of stochastics (mathematical statistics) and methods of theory of chaos and self-organization for studying such complex (chaotic) processes as postural tremor. It was established that when re-registering tremor in each subject by n=15 or n=30 obtained tremorograms do not exhibit normal distribution, and non-parametric distributions show distinctions at pairwise comparison on Wilcoxon test (only 2 or 3 pairs from 210 may belong to the same general population). Static physical load sharply changes this picture and the number of such ("similar") pairs increases. The estimation method for effect of a load on tremor is proposed. Simultaneously, within calculating quasi-attractors there is a clear picture of division of chaotic dynamics of tremor parameters with load and without load. Prospects of a new method application in physiological measurements are discussed. Limited method of stochas- tics in description of complexity is underlined, and necessity of calculation quasi-attractor´s parameters in phase space of state is proved.

Styles APA, Harvard, Vancouver, ISO, etc.

17

E. Gaume. « On the asymptotic behavior of flood peak distributions – theoretical results ». Hydrology and Earth System Sciences Discussions 2, n^o 5 (1 septembre 2005) : 1835–64. http://dx.doi.org/10.5194/hessd-2-1835-2005.

Texte intégral

Résumé :

Abstract. This paper presents some analytical results and numerical illustrations on the asymptotic properties of flood peak distributions obtained through derived flood frequency approaches. It confirms and extends the results of previous works: i.e. the shape of the flood peak distributions are asymptotically controlled by the rainfall statistical properties, given limited and reasonable assumptions concerning the rainfall-runoff process. This previous result is partial so far: only two types of rainfall intensity distributions have been considered (extreme value distributions of types I and II), and the impact of the rainfall spatial heterogeneity has not been studied. From a practical point of view, it provides a general framework for analysis of the outcomes of previous works based on derived flood frequency approaches and leads to some proposals for the estimation of very large return-period flood quantiles. This paper, focussed on asymptotic distribution properties, does not propose any new approach for the extrapolation of flood frequency distribution to estimate intermediate return period flood quantiles. Nevertheless, the large distance between frequent flood peak values and the asymptotic values as well as the simulations conducted in this paper help quantifying the ill condition of the problem of flood frequency distribution extrapolation: it illustrates how large the range of possibilities for the shapes of flood peak distributions is.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Gil, Carlos, Pedro Pascual et Manuel Rapún. « Regional Allocation of Structural Funds in the European Union ». Environment and Planning C : Government and Policy 20, n^o 5 (octobre 2002) : 655–77. http://dx.doi.org/10.1068/c21m.

Texte intégral

Résumé :

Economic disparities among the regions of the European Union are more pronounced than among countries. Structural Funds have played a crucial compensatory role, promoting the economic development and real convergence of lagging regions. The amount of resources destined to regional policy and the conflicts arising from its funding and distribution create the need for an adequate theoretical foundation or model to help politicians solve the distribution problem. In this paper we propose an empirical procedure to carry out and evaluate different distributions of funds for the periods 1989 – 93 and 1994 – 99. We begin with the estimation of an augmented production function to permit the calculation of the expected GDP per capita. We then propose a nonlinear programming method to simulate alternative distributions of Structural Funds among Objective 1 regions, based upon two different approaches: equal development, and equal opportunities. For these two approaches we calculate different possibilities, ranging from highly efficient to highly equitable, with the result that we are able to show the ‘frontier’ of optimal distributions. Finally, we evaluate these results and compare them with the real distribution.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Gaume, E. « On the asymptotic behavior of flood peak distributions ». Hydrology and Earth System Sciences 10, n^o 2 (26 avril 2006) : 233–43. http://dx.doi.org/10.5194/hess-10-233-2006.

Texte intégral

Résumé :

Abstract. This paper presents some analytical results and numerical illustrations on the asymptotic properties of flood peak distributions obtained through derived flood frequency approaches. It confirms and extends the results of previous works: i.e. the shape of the flood peak distributions are asymptotically controlled by the rainfall statistical properties, given limited and reasonable assumptions concerning the rainfall-runoff process. This result is partial so far: the impact of the rainfall spatial heterogeneity has not been studied for instance. From a practical point of view, it provides a general framework for analysis of the outcomes of previous works based on derived flood frequency approaches and leads to some proposals for the estimation of very large return-period flood quantiles. This paper, focussed on asymptotic distribution properties, does not propose any new approach for the extrapolation of flood frequency distribution to estimate intermediate return period flood quantiles. Nevertheless, the large distance between frequent flood peak values and the asymptotic values as well as the simulations conducted in this paper help quantifying the ill condition of the problem of flood frequency distribution extrapolation: it illustrates how large the range of possibilities for the shapes of flood peak distributions is.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Zubkov, Andrei M., et M. V. Filina. « Computation of distributions of statistics by means of Markov chains ». Discrete Mathematics and Applications 32, n^o 4 (1 août 2022) : 285–95. http://dx.doi.org/10.1515/dma-2022-0024.

Texte intégral

Résumé :

Abstract An approach to the construction of efficient algorithms for the exact computation of distributions of statistics by means of the Markov chains is described. The Pearson statistic, the number of empty cells for random allocations of particles, and the Kolmogorov – Smirnov statistic are considered as examples. Possibilities of extending the approach are discussed, in particular to the computation of the joint distributions of statistics.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Boumova, Silvia, Tanya Marinova, Tedis Ramaj et Maya Stoyanova. « Nonexistence of (17, 108, 3) ternary orthogonal array ». Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics 106 (12 décembre 2019) : 117–26. http://dx.doi.org/10.60063/gsu.fmi.106.117-126.

Texte intégral

Résumé :

We develop a combinatorial method for computing and reducing of the possibilities of distance distributions of ternary orthogonal array (TOA) of given parameters $(n, M, \tau)$. Using relations between distance distributions of arrays under consideration and their relatives we prove certain constraints on the distance distributions of TOAs. This allows us to collect rules for removing distance distributions as infeasible. The main result is nonexistence of $(17,108,34)$ TOA. Our approach allows substantial reduction of the number of feasible distance distributions for known arrays. This could be helpful for other investigations over the classification of the ternary orthogonal arrays.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Biasi, Glenn P., et Ray Weldon. « Quantitative Refinement of Calibrated14C Distributions ». Quaternary Research 41, n^o 1 (janvier 1994) : 1–18. http://dx.doi.org/10.1006/qres.1994.1001.

Texte intégral

Résumé :

AbstractA new method is presented for using known ordering or other relationships between14C samples to reduce14C dating uncertainty. The order of sample formation is often known from, for example, stratigraphic superposition, dendrochronology, or crosscutting field relations. Constraints such as a minimum time between dates and limits from historical information are also readily included. Dendrochronologically calibrated calendric date histograms initially represent each date. The method uses Bayes theorem and the relational constraints to upweight date ranges in each date distribution consistent with the other date distributions and the constraints, and downweight unlikely portions. The reweighted date distributions retain all dating possibilities present in the initial calibrated date distributions, but each date in the result now reflects the extra information such as ordering supplied through the constraints. In addition, one may add information incrementally, and thus analyze systematically its effect on all the date distributions. Thus, the method can be used to assess the consistency of the quantitative data at hand. The Bayesian approach also uses the empirical calibrated date distributions directly, so information is not lost prematurely by summarized dates to a mean and variance or "confidence intervals." The approach is illustrated with data from two densely sampled paleoseismic sites on the San Andreas Fault in southern California. An average reduction in14C date distribution variance of 59% is achieved using ordering information alone, and 85% is achieved by also applying sedimentation rate constraints and historical information.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Nikolayev, D. I., et K. Ullemeyer. « The Effect of Smoothing on ODF Reproduction ». Textures and Microstructures 25, n^o 2-4 (1 janvier 1996) : 149–57. http://dx.doi.org/10.1155/tsm.25.149.

Texte intégral

Résumé :

Although the smoothing of experimental pole-density data modifies the primary data set, the effect of such a procedure on the Orientation Distribution Function and on the interpretation of the texture was not considered until recently. The influence of smoothing on texture reproduction will be derived for the case, that the Orientation Distribution Function is approximated by a linear combination of normal distributions (ideal orientation components) and smoothing is carried out with normal distributions, too. The characteristic component parameters are well-suited to indicate changes of the Orientation Distribution Function. The observed texture variations as a consequence of smoothing lead to the conclusion, that moderate smoothing does not falsifythe texture. Several possibilities to control the effect of smoothing will be discussed. Based on the visual comparison of smoothed and unsmoothed pole-figures it is argued, that even extreme smoothing may be useful for some purposes.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Faraone, A., S. Magazù, G. Maisano, V. Villari et G. Maschio. « Possibilities and limits of photon correlation spectroscopy in determining polymer molecular weight distributions ». Macromolecular Chemistry and Physics 200, n^o 5 (1 mai 1999) : 1134–42. http://dx.doi.org/10.1002/(sici)1521-3935(19990501)200:5<1134 ::aid-macp1134>3.0.co;2-o.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

25

Mathew, Jismi, et Christophe Chesneau. « Marshall–Olkin Length-Biased Maxwell Distribution and Its Applications ». Mathematical and Computational Applications 25, n^o 4 (1 octobre 2020) : 65. http://dx.doi.org/10.3390/mca25040065.

Texte intégral

Résumé :

It is well established that classical one-parameter distributions lack the flexibility to model the characteristics of a complex random phenomenon. This fact motivates clever generalizations of these distributions by applying various mathematical schemes. In this paper, we contribute in extending the one-parameter length-biased Maxwell distribution through the famous Marshall–Olkin scheme. We thus introduce a new two-parameter lifetime distribution called the Marshall–Olkin length-biased Maxwell distribution. We emphasize the pliancy of the main functions, strong stochastic order results and versatile moments measures, including the mean, variance, skewness and kurtosis, offering more possibilities compared to the parental length-biased Maxwell distribution. The statistical characteristics of the new model are discussed on the basis of the maximum likelihood estimation method. Applications to simulated and practical data sets are presented. In particular, for five referenced data sets, we show that the proposed model outperforms five other comparable models, also well known for their fitting skills.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Barabanov, Alexey, Alexander Vorobyev, Alexei Gagarski, Oleg Shcherbakov et Larisa Vaishnene. « Angular distribution of fragments in neutron-induced nuclear fission at energies 1−200 MeV : Data, theoretical models and relevant problems ». EPJ Web of Conferences 256 (2021) : 00003. http://dx.doi.org/10.1051/epjconf/202125600003.

Texte intégral

Résumé :

In recent years, investigations of angular distributions of fragments in neutron-induced nuclear fission have been extended to intermediate energies, up to 200 MeV, as well as to a wide range of target isotopes. Using as an example the latest data obtained by our group for the reaction 237Np(n; f), we discuss the specific features of fission fragment angular distribution and present a method for their simulation based on the code TALYS. It is shown that a simplified model reasonably describes energy dependence of the angular distribution in the whole range 1–200 MeV. The ways to improve the model are discussed along with the possibilities to use it for obtaining new information on fission and pre-equilibrium processes in neutron-nucleus interaction. We consider also the relevant problems of describing fission fragment angular distributions.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Arratia, Richard, A. D. Barbour et Simon Tavaré. « On random polynomials over finite fields ». Mathematical Proceedings of the Cambridge Philosophical Society 114, n^o 2 (septembre 1993) : 347–68. http://dx.doi.org/10.1017/s0305004100071620.

Texte intégral

Résumé :

AbstractWe consider random monic polynomials of degree n over a finite field of q elements, chosen with all qn possibilities equally likely, factored into monic irreducible factors. More generally, relaxing the restriction that q be a prime power, we consider that multiset construction in which the total number of possibilities of weight n is qn. We establish various approximations for the joint distribution of factors, by giving upper bounds on the total variation distance to simpler discrete distributions. For example, the counts for particular factors are approximately independent and geometrically distributed, and the counts for all factors of sizes 1, 2, …, b, where b = O(n/log n), are approximated by independent negative binomial random variables. As another example, the joint distribution of the large factors is close to the joint distribution of the large cycles in a random permutation. We show how these discrete approximations imply a Brownian motion functional central limit theorem and a Poisson-Dirichiet limit theorem, together with appropriate error estimates. We also give Poisson approximations, with error bounds, for the distribution of the total number of factors.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Lorenz-Meyer, Dagmar. « Possibilities of Enacting and Researching Epistemic Communities ». Sociological Research Online 15, n^o 2 (mai 2010) : 161–73. http://dx.doi.org/10.5153/sro.2151.

Texte intégral

Résumé :

This article explores what the concept of epistemic community can contribute to studies of science and technology and to existing analytical frames of epistemic cultures, technosocial network and community of practice. Reviewing conceptions of epistemic community in political science, organisational studies and feminist epistemologies I suggest that heuristic dimensions include a focus on historical contingencies and timings; on particular epistemic projects and technologies that work as boundary objects; and on epistemic responsibilities and stratifications. These dimensions are further explored in two research vignettes. The first vignette follows the mobilisation and expectations of the Czech synchrotron user community at a funding event as a focal point for examining epistemic responsibilities and the genderings of community. The second vignette follows a biographical narrative about being and becoming a member of an epistemic community and amplifies the importance of different configurations of community. I argue that the contours, distributions and textures of an epistemic community cannot be studied at a single analytical site such as the laboratory and conclude by outlining what can be gained by using a refined concept of epistemic communities and sketching some strategies for further research.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Evans, Geoffrey T., Jake C. Rice et E. Michael P. Chadwick. « Patterns of Growth and Smolting of Atlantic Salmon (Salmo salar) Parr in a Southwestern Newfoundland River ». Canadian Journal of Fisheries and Aquatic Sciences 42, n^o 3 (1 mars 1985) : 539–43. http://dx.doi.org/10.1139/f85-071.

Texte intégral

Résumé :

A simple model of growth and smolting of Atlantic salmon (Salmo salar) parr, which can account for distributions of ages and lengths of random samples of sea-run smolts in Western Arm Brook, in northern Newfoundland, cannot account for distributions in Little Codroy River, in southwestern Newfoundland. Possible reasons for discrepancies include mortality dependent on growth rates, non-Gaussian growth rate distributions, and variability in individual growth rates. Smolt data do not allow us to reject any of these possibilities. Precocious maturation of male parr does not account for the discrepancies.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Oluwafunmilola, OLUBIYI, Adenike, OLAJIDE, Oluwamayowa Opeyimika et OLAYEMI Michael Sunday. « A New Approach of Presenting Lindley Expontiated Gumbel Distribution with Application to Environmental Data ». International Journal of Membrane Science and Technology 10, n^o 2 (29 octobre 2023) : 2649–57. http://dx.doi.org/10.15379/ijmst.v10i2.2935.

Texte intégral

Résumé :

The Lindley exponentiated Gumbel (LEGu) Distribution, a new family of probability distribution developed for modelling environmental data is introduced in this research paper. The investigation defines the new distribution's basic statistical properties, such as its shape, density function, hazard rate function, moment generation function, and maximum likelihood estimates of its model parameters. The study shows that, in comparison to other baseline distributions and comparators, increasing the number of parameters in the distribution improves its robustness and adaptability, making it more flexible in accommodating different types of data. The model is now more adaptable and can handle a wider range of data sets, making it a useful and effective tool for environmental modelling. The creation of the Lindley exponentiated Gumbel Distribution and the statistical qualities that go along with it bring up new possibilities for the analysis of environmental data, making a significant contribution to the larger initiatives in climate research and decision-making. The results of this study have the potential to advance our comprehension of environmental mechanisms and raise the precision of climate assessments and projections.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Grechin, S. G., P. P. Nikolaev et E. A. Sharandin. « Functional possibilities for forming different inverse population distributions in diode-side-pumped laser heads ». Quantum Electronics 44, n^o 10 (29 octobre 2014) : 912–20. http://dx.doi.org/10.1070/qe2014v044n10abeh015384.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

32

Voronina, Maria Yurievna, Alexey Alexeevich Kislitsyn et Yurii Nikolaevich Orlov. « Two-factor patterns construction in problems of texts classification ». Keldysh Institute Preprints, n^o 43 (2022) : 1–24. http://dx.doi.org/10.20948/prepr-2022-43.

Texte intégral

Résumé :

Two-factor patterns of empirical distributions of bigram frequencies for machine classification of texts by authors and subject are constructed. Text attributes are recognized by the nearest neighbor method in relation to reference distributions. The proximity between distributions is understood in the sense of the norm in L1. The "author-topic" pair of an unknown text is defined as a nearest neighbor pattern. The problem of recognizing the author regardless of the topic of the text and the topic regardless of the author is analyzed. The possibilities of enlarging and detailing classification features are also being investigated.

Styles APA, Harvard, Vancouver, ISO, etc.

33

SHIBATA, T. A. « MEASUREMENTS WITH POLARIZED HADRONS ». International Journal of Modern Physics A 19, n^o 07 (20 mars 2004) : 1089–98. http://dx.doi.org/10.1142/s0217751x04018993.

Texte intégral

Résumé :

Recent progress in physics with polarized hadrons is described with the emphasis on the spin structure of the nucleon. The nucleon spin problem, which was discovered by EMC in 1988, is now being studied in various experiments. Flavor separation of the quark helicity distributions has been made. Recent observations of asymmetries in deeply virtual Compton scattering (DVCS) and exclusive meson productions provide possibilities to access the total angluar momentum carried by quarks in the framework of generalized parton distributions. Single spin azimuthal asymmetries observed in semi-inclusive measurements provide a new handle to determine the transverse quark distributions which are basic but have never been measured so far.

Styles APA, Harvard, Vancouver, ISO, etc.

34

MAGDA, M. T., et J. D. LEYBA. « PRODUCTION OF HEAVY ELEMENTS BY TRANSFER OF MASSIVE CLUSTERS ». International Journal of Modern Physics E 01, n^o 02 (juin 1992) : 221–47. http://dx.doi.org/10.1142/s0218301392000114.

Texte intégral

Résumé :

A review of various models of multinucleon transfer reactions leading to heavy elements is given. A mechanism is proposed to describe these reactions based on the assumption that massive clusters are separated from the projectile and captured as a whole by the target nucleus. The modification of the primary isotopic distribution by fission and neutron evaporation is considered. Calculated isotopic distributions and cross sections are in good agreement with experimental data for the production of Z = 96–103 elements. Predictions of the model are used to explore the possibilities of producing transfermium elements by transfer reactions.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Saenger, P. « Mangrove vegetation : an evolutionary perspective ». Marine and Freshwater Research 49, n^o 4 (1998) : 277. http://dx.doi.org/10.1071/mf97139.

Texte intégral

Résumé :

The world-wide occurrence of mangrove vegetation and the modern floristic divergence between the Indo–Pacific and the Atlantic mangroves, can only be explained by historical processes, in that the composition of the modern mangrove flora at any one location, while subject to present-day climatic and geographical conditions, is largely relict. Although several interpretations have been offered to relate mangrove distributions to past events, none has been universally accepted. What is explored here, is that there are several historical and modern processes which in combination, have resulted in the present day distribution of mangroves. Evolutionary processes are reviewed from the fossil record and from the data on continental drift. Next, the ecological processes that are selectively acting on the various species and their distributions are examined with particular emphasis on aridity, temperature and latitudinal attentuation of species. Finally, some modern anthropogenic processes (e.g. species introductions, over-exploitation and habitat modification, afforestation) are examined in terms of their effects on mangrove distribution. As an outcome of these various processes, the modern mangrove vegetation is analysed particularly in relation to regions of endemism, vicariance among species, discontinuous distributions, hybridization and divergence. Finally, some speculation is offered in terms of future trends and evolutionary possibilities.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Ovsienko, M. A. « 3D STUDY OF SEISMICITY : ESTIMATIONS OF ACCURACY AND REPRESENTATIVENESS OF MODELS, SEISMOTECTONIC STRESSES STABILITY AND RHEOLOGICAL POSSIBILITIES FOR THE INTERPRETATION OF SPATIAL DISTRIBUTIONS EARTHQUAKES ». Regional problems 25, n^o 3 (2022) : 85–87. http://dx.doi.org/10.31433/2618-9593-2022-25-3-85-87.

Texte intégral

Résumé :

With an increase in the number of seismic stations and their throughput in the Amur region, the representativeness of the catalog grows. The author has analyzed the earthquake magnitudes distribution in four time ranges and revealed their static regularity. Earthquake magnitude distributions mark large tectonic structures. It allows the study of three-dimensional geological structure of the Amur region in continuous space, and over a wide time range.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Garmeh, Saeed, Mehdi Jadidi et Ali Dolatabadi. « Cold Spray for Additive Manufacturing : Possibilities and Challenges ». Key Engineering Materials 813 (juillet 2019) : 423–28. http://dx.doi.org/10.4028/www.scientific.net/kem.813.423.

Texte intégral

Résumé :

Cold spray (CS) is a deposition technique to form a coating from the particles with temperature lower than their melting point. In this technique, particles are accelerated by a supersonic flow of a carrier gas such as air or nitrogen. Upon impact, particles undergo significant plastic deformation that bonds them to the substrate. Since the particles are not molten, this deposition method does not apply a lot of heat to the substrate and this makes CS the best candidate for temperature sensitive and oxygen sensitive materials. CS can be adapted to form 3D objects following layer-by-layer approach. This is called cold gas dynamic manufacturing (CGDM) or cold spray as additive manufacturing. Developing complex shapes by CGDM may result in formation of inclined surfaces, corners and sharp edges. Deposition in those regions is often accompanied with challenges that affect the accuracy and efficiency of the manufacturing. In this study, CGDM for two typical shapes such as cylinder and frustum on a flat substrate has been simulated to represent the additively manufactured parts. Particle trajectories and impact conditions i.e. velocity and size distributions have been compared. The results of numerical modelling provided useful information for understanding the limitations and challenges associated with CGDM that can help us to improve the quality and precision of particle deposition.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Venter, Gary G. « Generalized Linear Models beyond the Exponential Family with Loss Reserve Applications ». ASTIN Bulletin 37, n^o 02 (novembre 2007) : 345–64. http://dx.doi.org/10.2143/ast.37.2.2024071.

Texte intégral

Résumé :

The formulation of generalized linear models in Klugman, Panjer and Willmot (2004) is a bit more general than is often seen, in that the residuals are not restricted to following a member of the exponential family. Some of the distributions this allows have potentially useful applications. The cost is that there is no longer a single form for the likelihood function, so each has to be fit directly. Here the use of loss distributions (frequency, severity and aggregate) in generalized linear models is addressed, along with a few other possibilities.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Venter, Gary G. « Generalized Linear Models beyond the Exponential Family with Loss Reserve Applications ». ASTIN Bulletin 37, n^o 2 (novembre 2007) : 345–64. http://dx.doi.org/10.1017/s0515036100014902.

Texte intégral

Résumé :

The formulation of generalized linear models in Klugman, Panjer and Willmot (2004) is a bit more general than is often seen, in that the residuals are not restricted to following a member of the exponential family. Some of the distributions this allows have potentially useful applications. The cost is that there is no longer a single form for the likelihood function, so each has to be fit directly. Here the use of loss distributions (frequency, severity and aggregate) in generalized linear models is addressed, along with a few other possibilities.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Magnusson, Helena, et Nils Sandberg. « Statistical Analysis of Misorientation Distributions From Growth Selection Experiments in Iron–3% Si ». Textures and Microstructures 34, n^o 4 (1 janvier 2000) : 255–62. http://dx.doi.org/10.1155/tsm.34.255.

Texte intégral

Résumé :

The frequency of occurrence of differently misoriented grain boundaries in growth selection experiments in silicon–iron was reported by Ibe and Lücke and has been the basis of many texture models. However, this pattern of behaviour bears much similarity to misorientation frequencies calculated from random textures. A comparison of the experimental and computed frequency distribution shows that there are statistically significant differences and therefore that some possibilities for growth selection do exist

Styles APA, Harvard, Vancouver, ISO, etc.

41

Bhatt, Rushi, et Kishor Barman. « Global Dynamics of Online Group Conversations ». Proceedings of the International AAAI Conference on Web and Social Media 6, n^o 1 (3 août 2021) : 403–6. http://dx.doi.org/10.1609/icwsm.v6i1.14319.

Texte intégral

Résumé :

Public online groups allow individuals to carry out conver- sations of common interests. Study of such group conversa- tions provides a unique opportunity to study patterns of hu- man conversations without violating individual privacy. The observational studies conducted in this paper are an attempt to identify the main correlates of continued growth of con- versations, thereby clearing the path to developing predictive models user participation. We study temporal evolution of online group discussions. Surprisingly, we find that individual discussion groups dis- play distinctively q-exponential shaped inter-message times to reply distributions, unlike the power law distributions seen in email conversations. We show, using simulations, that the heavy-tailed distribution of time to reply, which we also ob- serve when all data is combined, originate from mixtures of q-exponentials. We also find that popular threads come to be so from the very beginning as opposed to evolving to be more popular as they grow. This raises new possibilities for devel- oping generative models of thread growth.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Boroń, Sylwia, et Przemysław Kubica. « Optymalizacja procesu projektowego stałych urządzeń gaśniczych gazowych za pomocą metod numerycznych CFD ». Przegląd Naukowy Inżynieria i Kształtowanie Środowiska 27, n^o 4 (10 janvier 2019) : 524–35. http://dx.doi.org/10.22630/pniks.2018.27.4.49.

Texte intégral

Résumé :

Computational fluid dynamics (CFD) is a modern tool used in engineering practice that can be used to optimize the design of fixed gaseous extinguishing systems (FGE-systems). The paper presents selected possibilities of practical application of numerical methods for evaluation of individual FGE-systems design parameters. The main feature of CFD modeling is the ability to obtain gas concentration distributions, flow directions of fire extinguishing mixture in a protected room and spatial distribution of air temperature, which is an important cognitive value of this method. The results show the potential for practical use of CFD methods in the modeling of extinguishing gas protection of real properties.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Hambly, Ben. « On the limiting distribution of a supercritical branching process in a random environment ». Journal of Applied Probability 29, n^o 3 (septembre 1992) : 499–518. http://dx.doi.org/10.2307/3214889.

Texte intégral

Résumé :

We consider an increasing supercritical branching process in a random environment and obtain bounds on the Laplace transform and distribution function of the limiting random variable. There are two possibilities that can be distinguished depending on the nature of the component distributions of the environment. If the minimum family size of each is 1, the growth will be as a power depending on a parameter α. If the minimum family sizes of some are greater than 1, it will be exponential, depending on a parameter γ. We obtain bounds on the distribution function analogous to those found for the simple Galton-Watson case. It is not possible to obtain exact estimates and we are only able to obtain bounds to within ε of the parameters.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Hambly, Ben. « On the limiting distribution of a supercritical branching process in a random environment ». Journal of Applied Probability 29, n^o 03 (septembre 1992) : 499–518. http://dx.doi.org/10.1017/s0021900200043345.

Texte intégral

Résumé :

We consider an increasing supercritical branching process in a random environment and obtain bounds on the Laplace transform and distribution function of the limiting random variable. There are two possibilities that can be distinguished depending on the nature of the component distributions of the environment. If the minimum family size of each is 1, the growth will be as a power depending on a parameter α. If the minimum family sizes of some are greater than 1, it will be exponential, depending on a parameter γ. We obtain bounds on the distribution function analogous to those found for the simple Galton-Watson case. It is not possible to obtain exact estimates and we are only able to obtain bounds to within ε of the parameters.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Yano, Jun-Ichi, Andrew J. Heymsfield et Aaron Bansemer. « Determination of the Ice Particle Size Distributions Using Observations as the Integrated Constraints ». Journal of the Atmospheric Sciences 75, n^o 3 (28 février 2018) : 787–804. http://dx.doi.org/10.1175/jas-d-17-0145.1.

Texte intégral

Résumé :

Abstract The possibility is suggested of estimating particle size distributions (PSD) solely based on the bulk quantities of the hydrometeors. The method, inspired by the maximum entropy principle, can be applied to any predefined general PSD form as long as the number of the free parameters is equal to or less than that of the bulk quantities available. As long as an adopted distribution is “physically based,” these bulk characterizations can recover a fairly accurate PSD estimate. This method is tested for ice particle measurements from the Tropical Composition, Cloud and Climate Coupling Experiment (TC4). The total particle number, total mass, and mean size are taken as bulk quantities. The gamma distribution and two distributions obtained under the maximum entropy principle by taking the size and the particle mass, respectively, as a restriction variable are adopted for fit. The fitting error for the two maximum entropy–based distributions is comparable to that of a standard direct fitting method with the gamma distribution. The same procedure works almost equally well when the mean size is removed from the constraint, especially for an exponential distribution. The results suggest that the total particle number and the total mass of the hydrometeors are sufficient for determining the PSD to a reasonable accuracy when a “physically based” distribution is assumed. In addition to the in situ cloud measurements, remote sensing measurements such as those from radar as well as satellite can be adopted as physical constraints. Possibilities of exploiting different types of measurements should be further pursued.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Phalan, Ben, Rhys Green et Andrew Balmford. « Closing yield gaps : perils and possibilities for biodiversity conservation ». Philosophical Transactions of the Royal Society B : Biological Sciences 369, n^o 1639 (5 avril 2014) : 20120285. http://dx.doi.org/10.1098/rstb.2012.0285.

Texte intégral

Résumé :

Increasing agricultural productivity to ‘close yield gaps’ creates both perils and possibilities for biodiversity conservation. Yield increases often have negative impacts on species within farmland, but at the same time could potentially make it more feasible to minimize further cropland expansion into natural habitats. We combine global data on yield gaps, projected future production of maize, rice and wheat, the distributions of birds and their estimated sensitivity to changes in crop yields to map where it might be most beneficial for bird conservation to close yield gaps as part of a land-sparing strategy, and where doing so might be most damaging. Closing yield gaps to attainable levels to meet projected demand in 2050 could potentially help spare an area equivalent to that of the Indian subcontinent. Increasing yields this much on existing farmland would inevitably reduce its biodiversity, and therefore we advocate efforts both to constrain further increases in global food demand, and to identify the least harmful ways of increasing yields. The land-sparing potential of closing yield gaps will not be realized without specific mechanisms to link yield increases to habitat protection (and restoration), and therefore we suggest that conservationists, farmers, crop scientists and policy-makers collaborate to explore promising mechanisms.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Morawski, Leszek. « Imputacja wynagrodzeń brutto z pracy stałej w badaniach budżetów gospodarstw domowych ». Wiadomości Statystyczne. The Polish Statistician 2011, n^o 1 (28 janvier 2011) : 19–29. http://dx.doi.org/10.59139/ws.2011.01.2.

Texte intégral

Résumé :

Results of the imputation of gross salary for permanent job based on household budget surveys are presented in the article. A comparing results with declared gross salary values in EU-SILC showed significant similarity of both distributions. This creates good possibilities to use the SILC data in micro-economic analyses of the labour market.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Chernykh, Aleksey Nikolaevich, Valery Ivanovich Kostjuchenko, Konstantin Sergeevich Krasilschikov et Dmitry Alekseevich Zhidkov. « USING MC TOPAS FOR DESIGNING SYSTEMS FOR THE FORMATION OF DOSE DISTRIBUTIONS FOR PROTON RADIATION THERAPY COMPLEXES ». ITNOU : Information technologies in science, education and management, n^o 20 (juin 2023) : 32–42. http://dx.doi.org/10.47501/itnou.2023.1.32-42.

Texte intégral

Résumé :

Discusses the possibilities of using the MC TOPAS and GEANT4 libraries for design of dose distribution generation systems. It is shown that both passive and dynamic elements can be modeled. Variants of various device that can be used for irradiation in oncophthalmological targets are presented .

Styles APA, Harvard, Vancouver, ISO, etc.

49

Nebelsick, James H. « Biodiversity of Shallow-Water Red Sea Echinoids : Implications For the Fossil Record ». Journal of the Marine Biological Association of the United Kingdom 76, n^o 1 (février 1996) : 185–94. http://dx.doi.org/10.1017/s0025315400029118.

Texte intégral

Résumé :

Determination of fossil echinoid diversities is an important aspect of detailed palaeon- tological studies. The comparison of recent and fossil associations can be used to elucidate the problems of determination of fossil echinoid distributions. Actuopalaeontological studies of echinoids from the Red Sea (northern Bay of Safaga, Egypt) have shown that the study of fragments within bulk sediment samples greatly increased the possibilities for determining echinoid presence and distribution. The results show the restricted distribution as well as the differential preservation potential of the various echinoids.The distribution of echinoids is primarily controlled by grain size, food availability, exposure to current activity, and predation pressure. Regular and irregular sea-urchins show the expected disjunct distributions with the former showing a more undifferentiated distribution to various hard substrates. Irregular echinoids are tightly restricted to particular types of soft substrates reflecting their adaptation to the specific grain size of the sediments. Co-occurring irregular sea-urchins show a spatial differentiation into shallow (clypeasteroids) and deeper burrowers (spatangoids). This investigation shows that important echinoid species known to occur in the Red Sea are lacking or are very rare within the study area, although a large number of different facies types are present. Patchy distributions are present for both regular and irregular sea-urchins. The determination of biodiversity is therefore seen to be largely dependent on the scale of investigation.An important implication for fossil echinoid presence are the differential effects of taphonomic agents on the various test architectures. Some species are well represented due to their common occurrences, and their comparatively robust tests or test fragments.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Koons, John P. « Design Factors With Realistic I/O Distributions ». Journal of Electronic Packaging 113, n^o 1 (1 mars 1991) : 76–80. http://dx.doi.org/10.1115/1.2905370.

Texte intégral

Résumé :

This paper explores some design factors, including wireability, of packages in which the number of I/O per module to be interconnected varies widely. This is of interest because it is common for memory card designs and for work station and personal computer printed circuit designs. Memory cards often have a few relatively high pin count control logic modules supporting many low pin count array modules. Work station and personal computer cards often use low density “glue” logic modules with a few microprocessor modules and their high function supports. Printed circuit cost and performance factors are examined by example. Differences between area array and perimeter escape components and leverage possibilities of multi-chip modules are examined. A background tutorial on wireability analysis is given. The algorithm used was developed by Wadie Mikhail several years ago. Analyses are based on the length of wire paths available in a given design, the length of wire needed and the utilizations of the available paths. Utilization guidelines are suggested. Alternative wireability algorithms are identified and briefly discussed. Although the examples are given for cases of modules on cards, the methodologies and general conclusions are valid at other packaging levels; for example, for chips on multi-chip modules.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Distributions of possibilities »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres