Search results for "Normal"

Elliptically Symmetric Distributions: A Review of Achieved Results and Open Issues

2005

The spherically and elliptically symmetrical distributions are used in different statistical areas for different purposes such as the description of multivariate data, in order to find alternatives to the normal distribution in multinormality tests and in the creation of statistical models in which the usual assumption of normality is not realistic. Some achieved results, open issues and some proposals for their use in applications, especially in the financial area, are here presented.

Über eine methode zur bestimmung der intensität komplexer photopeaks

1966

Abstract Analysing photopeaks really occuring in γ-ray spectra their asymmetrical structure can easily be demonstrated. To describe the shape of photopeaks this study therefore recommends the use of empirical functions instead of the normal distribution function. It can be shown, that in a wide energy and intensity range photopeaks are exactly described by two empirical functions which are normalized with respect to the fractional peak height. Taking account of this fact, a new procedure is derived which allows the decomposition of overlapping photopeaks even in the case of small energy distance and unfavorable intensity ratio. The method applied to numerous examples under practical conditi…

Probabilities in Risk Management

2014

A project is generally a complex undertaking in which most things are uncertain (durations, costs, project and suppliers performance, weather, soil geology, public reaction, etc.), and thus, risk permeates everything. Risk is closely related to uncertainty, and the latter with probabilities and distributions the conceptual aspects of which are explained in Chap. 9. It is inconceivable to address risk without considering probabilities of occurrence, and the measures that must be taken to prevent or mitigate risk; in that sense, the ‘buffer’ concept is introduced. In Chap. 2, a comparison was mentioned between CPM, PERT and MC; now, Chap. 3 proposes a case for numerically demonstrating the ad…

Project During Execution – Strategy – Updating

2014

This chapter fundamentally examines project performance during its execution period, however, risk must always be considered, especially at the very beginning of the project when the risk is normally maximum, and at each update. In the Project Monitoring stage, this chapter explores what happens with foreseen risks, that is, if they really happened or not and their consequences. In the Project Control stage, the chapter uses Earned Value Analysis and examines Performance Factors, which are used to predict completion regarding time and cost. However, because these calculations are based on past performance, there is always the risk that this performance will not be replicated in the future, …

A Synthetic Approach to Multivariate Normal Clustering

1982

Two methods have been suggested for grouping together observations originated from the same multivariate normal distributions, both based on a maximum-likelihood (ML) estimation, but leading to different conclusions. In this paper we compare the use of Day’s approach and that of Scott and Symons in clustering procedures from the theoretical and computational point of view. Based on this comparison, we suggest an approach unifying those approaches. The workability of the approach will be verified by numerical experiments.

Umbilicity of surfaces with orthogonal asymptotic lines in R4

2002

We study some properties of surfaces in 4-space all whose points are umbilic with respect to some normal field. In particular, we show that this condition is equivalent to the orthogonality of the (globally defined) fields of asymptotic directions. We also analyze necessary and sufficient conditions for the hypersphericity of surfaces in 4-space.  2002 Elsevier Science B.V. All rights reserved.

The horospherical geometry of surfaces in hyperbolic 4-space

2006

We study some geometrical properties associated to the contacts of surfaces with hyperhorospheres inH + 4 (−1). We introduce the concepts of osculating hyperhorospheres, horobinormals, horoasymptotic directions and horospherical points and provide conditions ensuring their existence. We show that totally semiumbilical surfaces have orthogonal horoasymptotic directions.

HEAT FLUX IN SUPERFLUID TRANSITION AND IN TURBULENT HELIUM COUNTERFLOW

Wormlike Polystyrene Brushes in Thin Films

1997

Mono- and multilayer films were prepared on mica by solution casting of a high molecular weight polymacromonomer, i.e., a polymethacrylate of about 1000 repeating units each of which was substituted by a polystyrene chain with a molecular weight of about 5000 Da. The films were studied by tapping scanning force microscopy. The material showed a remarkable preference for forming well-defined monolayers of a thickness of 6.5 ± 0.2 nm consistent with the hard core diameter of the collapsed cylindrical brush molecules. When the films were probed with high normal force, the single molecules were observed to organize in a dense nematic-like packing as expected for inherently stiff molecules. In o…

Bourn-normal monomorphisms in regular Mal’tsev categories

2017

Normal monomorphisms in the sense of Bourn describe the equivalence classes of an internal equivalence relation. Although the definition is given in the fairly general setting of a category with finite limits, later investigations on this subject often focus on protomodular settings, where normality becomes a property. This paper clarifies the connections between internal equivalence relations and Bourn-normal monomorphisms in regular Mal’tesv categories with pushouts of split monomorphisms along arbitrary morphisms, whereas a full description is achieved for quasi-pointed regular Mal’tsev categories with pushouts of split monomorphisms along arbitrary morphisms.