scholarly journals THE EFFICIENCY ANALYSIS OF GENERALIZED VARIANCE ALGORITHM UNDER THE TREND OF MULTIDIMENSIONAL SCATTERING

2021 ◽  
Vol 3 (65) ◽  
pp. 56-60
Author(s):  
Viktoriya V. Ovsyannikova ◽  
Keyword(s):  
Numerical Methods ◽  
Covariance Matrix ◽  
Gradual Increase ◽  
Average Length ◽  
Efficiency Analysis ◽  
Generalized Variance ◽  
Control Efficiency ◽  
The Moment

The generalized variance algorithm is used to control the multidimensional scattering of the process. The generalized variance is understood as the determinant of the covariance matrix of the process. The control efficiency is estimated by the average length of the series, that is the number of observations from the moment of violation of the process to the moment of detection of this violation. Both analytical and numerical methods can be used to estimate the average length of the series for different control types. One of the most common types of the process violation is an abrupt or gradual increase in its dispersion. The aim of the article is to estimate the average length of the series of the generalized dispersion map under the trend of multidimensional scattering.

scholarly journals On Asymptotic Efficiency of the M2M4 Signal-to-Noise Estimator for Deterministic Complex Sinusoids

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4950
Author(s):  
Gianmarco Romano
Keyword(s):  
Covariance Matrix ◽  
Gaussian Noise ◽  
Asymptotic Efficiency ◽  
Noise Power ◽  
Finite Sample ◽  
Signal To Noise ◽  
Numerical Examples ◽  
Unknown Phase ◽  
The Moment ◽  
Asymptotically Efficient

The moment-based M2M4 signal-to-noise (SNR) estimator was proposed for a complex sinusoidal signal with a deterministic but unknown phase corrupted by additive Gaussian noise by Sekhar and Sreenivas. The authors studied its performances only through numerical examples and concluded that the proposed estimator is asymptotically efficient and exhibits finite sample super-efficiency for some combinations of signal and noise power. In this paper, we derive the analytical asymptotic performances of the proposed M2M4 SNR estimator, and we show that, contrary to what it has been concluded by Sekhar and Sreenivas, the proposed estimator is neither (asymptotically) efficient nor super-efficient. We also show that when dealing with deterministic signals, the covariance matrix needed to derive asymptotic performances must be explicitly derived as its known general form for random signals cannot be extended to deterministic signals. Numerical examples are provided whose results confirm the analytical findings.

scholarly journals Morphology of seeds, seedlings, and young plants of Dimorphandra gardneriana Tul

2019 ◽  
Vol 40 (3) ◽  
pp. 1063
Author(s):  
Sueli Silva Santos Moura ◽  
Rosemere dos Santos Silva ◽  
Edna Ursulino Alves ◽  
Edilma Pereira Gonçalves ◽  
Lenyneves Duarte Alvino de Araújo ◽  
...  
Keyword(s):  
Average Length ◽  
Primary Root ◽  
Morphological Characteristics ◽  
Phase Curve ◽  
Seed Shape ◽  
Morphological Aspects ◽  
Seed Analysis ◽  
Three Phase ◽  
The Moment ◽  
Seeds Germination

Dimorphandra gardneriana Tul. is a legume, the fruits of which are used in routine extraction by the pharmaceutical industry. The objective was to study the morphological aspects of seeds, germination, seedlings, and young plants of Dimorphandra gardneriana Tul. The study was conducted at the Laboratory of Seed Analysis (LAS), Center of Agricultural Sciences, Federal University of Paraíba (CCA-UFPB), Areia - PB. The external morphological characteristics observed of the seeds were color, texture, and consistency of the teguments; seed shape; hilum and micropyle position; color and thickness of raphe and other structures present; besides internal embryo characteristics (cotyledons, hypocotyl-radicle axis, plumule, and central cylinder); and presence of the endosperm. The seed imbibition curve was determined by the weight of the seeds over a period of 90 h, evaluated every 6 h, with germination being considered as the protrusion of the primary root, or the moment when the primary root breaks the integument, and normal seedlings were evaluated on the 5th day after sowing. Most of the morphological characteristics identified in the plants and seedlings of D. gardneriana resembled those observed for other species of the same genus. The seeds of D. gardneriana Tul., were medium sized, with an average length of 11.95 mm, width of 5.33 mm, and thickness of 4.3 mm, unitegmic with a hard tegument, and impermeable to water. The process of imbibition of the seeds was initially slow and the three-phase curve of imbibition was not clear. The germination was epigeic and phanerocotiledonar and began on the 5th day after sowing.

scholarly journals The use of principal components and univariate charts to control multivariate processes

2008 ◽  
Vol 28 (1) ◽  
pp. 173-196 ◽  
Author(s):  
Marcela A. G. Machado ◽  
Antonio F. B. Costa
Keyword(s):  
Dimensionality Reduction ◽  
Covariance Matrix ◽  
Principal Components ◽  
Control Charts ◽  
Principal Component ◽  
Multivariate Processes ◽  
Generalized Variance ◽  
Overall Performance ◽  
The Way

In this article, we evaluate the performance of the T² chart based on the principal components (PC X chart) and the simultaneous univariate control charts based on the original variables (SU charts) or based on the principal components (SUPC charts). The main reason to consider the PC chart lies on the dimensionality reduction. However, depending on the disturbance and on the way the original variables are related, the chart is very slow in signaling, except when all variables are negatively correlated and the principal component is wisely selected. Comparing the SU , the SUPC and the T² charts we conclude that the SU X charts (SUPC charts) have a better overall performance when the variables are positively (negatively) correlated. We also develop the expression to obtain the power of two S² charts designed for monitoring the covariance matrix. These joint S² charts are, in the majority of the cases, more efficient than the generalized variance chart.

Numerical Modeling of Fragmentation Characteristics of Explosive Fragmentation Munitions

2002 ◽  
Author(s):  
Vladimir M. Gold
Keyword(s):  
High Speed ◽  
Average Length ◽  
Three Dimensional ◽  
Fragmentation Model ◽  
Computational Technique ◽  
Entire Body ◽  
Detonation Products ◽  
Explosive Fragmentation ◽  
Break Up ◽  
The Moment

Numerical simulations of explosive fragmentation munitions presented in this work integrate three-dimensional axisymmetric hydrocode analyses with analytical fragmentation modeling. The developed analytical fragmentation model is based on the Mott’s theory of break-up of cylindrical “ring-bombs” (Mott, 1947), in which the average length of fragments is a function of the radius and velocity of the ring at the moment of break-up, and the mechanical properties of the metal. The fundamental assumption of the model is that the fragmentation occurs instantly throughout the entire body of the shell. Adopting Mott’s critical fracture strain concept (Mott, 1947), the moment of the shell break-up is identified in terms of the high explosive detonation products volume expansions, V/V0. The assumed fragmentation time determined from the high-speed photographic data of Pearson (1990) had been approximately three volume expansions, the fragmentation being defined as the instant at which the detonation products first appear as they emanate from the fractures in the shell. The newly developed computational technique is applied to both the natural and preformed explosive fragmentation munitions problems. Considering relative simplicity of the model, the accuracy of the prediction of fragment spray experimental data is rather remarkable.

scholarly journals Experiența maternității în cel mai mare penitenciar de femei din Mexic

Transilvania ◽  
2020 ◽  
pp. 82-89
Author(s):  
Ioana Dana Obrinteschi Iancu
Keyword(s):  
Mexico City ◽  
Emotional Development ◽  
Average Length ◽  
Rehabilitation Center ◽  
Female Prisoners ◽  
Social Rehabilitation ◽  
The Social ◽  
Women's Incarceration ◽  
Women's Prison ◽  
The Moment

This research represents a radiography of motherhood in the largest Women’s Prison in Mexico and Latin America - Saint Martha Social Rehabilitation Center for Women, located in Mexico City. In April 2020 there were detained 1247 women, 80% of them mothers. The focus of the study is on those female prisoners who became mothers during their detention period and chose to keep their babies with them inside the prison. Interviews have revealed that the average length of their sentence is approximately 27 years and, in many cases, the baby’s father is in prison as well. The study starts with analyzing the social costs of women’s incarceration and follows the respondents’ path, from the moment they find out that they are pregnant to day-to-day aspects of a mother’s and a child’s life in a prison and to the moment they are separated from their children. The reasons why couples decide to have a baby are taken into account, along with the living conditions, the baby’s nutrition, health care, early education and the way the mother expects her baby’s emotional development to be affected, by the fact that he/she had spent the first years of life in prison.

A PROPOSAL FOR MULTI-ASSET GENERALIZED VARIANCE SWAPS

2019 ◽  
Vol 14 (04) ◽  
pp. 1950019
Author(s):  
SUBHOJIT BISWAS ◽  
DIGANTA MUKHERJEE
Keyword(s):  
Financial Markets ◽  
Covariance Matrix ◽  
Maximum Eigenvalue ◽  
Variance Swaps ◽  
Numerical Examples ◽  
Generalized Variance ◽  
Multiple Assets ◽  
Markov Modulated

This paper proposes swaps on two important new measures of generalized variance, namely the maximum eigenvalue and trace of the covariance matrix of the assets involved. We price these generalized variance swaps for financial markets with Markov-modulated volatilities. We consider multiple assets in the portfolio for theoretical purpose and demonstrate our approach with numerical examples taking three stocks in the portfolio. The results obtained in this paper have important implications for the commodity sector where such swaps would be useful for hedging risk.

Control Efficiency Analysis of Linear Oscillating Mechatronic Device

2009 ◽  
Vol 147-149 ◽  
pp. 197-202
Author(s):  
Audrius Senulis ◽  
Eleonora Guseinovienė ◽  
Viktoras Cirtautas ◽  
Valdas Jankūnas ◽  
Lionė Urmonienė
Keyword(s):  
Efficiency Analysis ◽  
Open Loop ◽  
Voltage Source ◽  
Square Wave ◽  
Control Efficiency ◽  
Control Power ◽  
Thyristor Control ◽  
Piston Stroke ◽  
Pulsating Current ◽  
Selection Of

This paper deals with the control efficiency analysis of the linear oscillating mechatronic device (linear oscillating synchronous motor–compressor). These mechatronic devices can be controlled by using thyristor control [1, 4], square-wave voltage [2, 3], ect. There is analyzed the case, when square-wave voltage pulses’ frequency is changed and so the piston stroke duration time is reduced. The control of piston stroke changes the energetic parameters of the mechatronic device. This type of controlling has one disadvantage – it needs a DC voltage source. The pulsating voltage control is based on thyristor control system and does not have the previously mentioned disadvantage, because uses the AC voltage source, but both control ways have influence to the energetic parameters due to higher harmonics. The analysis of the chosen mechatronic device (open-loop tests) is based on comparing the modeling and experimental results with respect to power losses, simplicity of the control, power factor and disturbances to the supply system. These results are important for the optimal design of the drive with oscillating synchronous pulsating current motors and the selection of control type for the different type of load.

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