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572. A Riemann approach to random variation
- Creator:
- Muldowney, Patrick
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Henstock integral, probability, and Brownian motion
- Language:
- English
- Description:
- This essay outlines a generalized Riemann approach to the analysis of random variation and illustrates it by a construction of Brownian motion in a new and simple manner.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
573. A Riemann-type definition for the double Denjoy integral of Chelidze and Djvarsheishvili
- Creator:
- Ye, Guoju and Lee, Peng-Yee
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- approximately continuous integral, Denjoy integral, and Chelidze-Djvarsheishvili integral
- Language:
- English
- Description:
- Summary: We give a Riemann-type definition of the double Denjoy integral of Chelidze and Djvarsheishvili using the new concept of CD filtering.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
574. A role of the coefficient of the differential term in qualitative theory of half-linear equations
- Creator:
- Řehák, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- half-linear dynamic equation, time scale, transformation, comparison theorem, and oscillation criteria
- Language:
- English
- Description:
- The aim of this contribution is to study the role of the coefficient r in the qualitative theory of the equation (r(t)Φ(y ∆))∆+p(t)Φ(y σ ) = 0, where Φ(u) = |u| α−1 sgn u with α > 1. We discuss sign and smoothness conditions posed on r, (non)availability of some transformations, and mainly we show how the behavior of r, along with the behavior of the graininess of the time scale, affect some comparison results and (non)oscillation criteria. At the same time we provide a survey of recent results acquired by sophisticated modifications of the Riccati type technique, which are supplemented by some new observations.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
575. A sample-time adjusted feedback for robust bounded output stabilization
- Creator:
- Ordaz, Patricio, Alazki, Hussain, and Poznyak, Alexander
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- sample-time data, attractive ellipsoid, state extimation, saturated control process, and flexible arm system
- Language:
- English
- Description:
- This paper deals with a bounded control design for a class of nonlinear systems where the mathematical model may be not explicitly given. This class of uncertain nonlinear systems governed by a system of ODE with quasi-Lipschitz right-hand side and containing external perturbations as well. The Attractive Ellipsoid Method (AEM) application permits to describe the class of nonlinear feedbacks (containing a nonlinear projection operator, a linear state estimator and a feedback matrix-gain) guaranteeing a boundedness of all possible trajectories around the origin. To fulfill this property some modification of AEM are introduced: basically, some sort of sample-time corrections of the feedback parameters are required. The optimization of feedback within this class of controllers is associated with the selection of the feedback parameters which provide the trajectory converges within an ellipsoid of a "minimal size". The effectiveness of the suggested approach is illustrated by its application to a flexible arm system).
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
576. A scalar Volterra derivative for the PoU-integral
- Creator:
- Marraffa, V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Pettis integral, McShane integral, PoU integral, and Volterra derivativ
- Language:
- English
- Description:
- A weak form of the Henstock Lemma for the PoU-integrable functions is given. This allows to prove the existence of a scalar Volterra derivative for the PoU-integral. Also the PoU-integrable functions are characterized by means of Pettis integrability and a condition involving finite pseudopartitions.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
577. A search of tidal interaction in the binary system λ And
- Creator:
- Głębocki, R., Bielicz, E., Pastuszka, Z., and Sikorski, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- astrophysics, tidal interaction, and binary system λ And
- Language:
- Czech
- Description:
- 31 UV spectra obtained with tne LWR camera of the lUE satellite in the period 1978-83 were analysed. Changes of Mg II h and k emissions are evident but there is no evident correlation between emission intensity of Mg II and orbital or photometric phase. Using three various methods of analysis of possible periodicity in variation of Mg II h and k emission intensities we have found reál chanes in h + k fluxes with period equal to the half of the orbital one, 0.5 Porb = 10.2606. We interpret this effect as evidence of direct influence of tidal inxeraction of secondary component on the chromospheric structure of the primary. Evident minimum of the Mg II h and k intensity is observed when the tides are on the line of sight and maximum when both tidal bulges are visible. Difference between maximum and minimum of total flux of k line is equal to about 20%, while the shape of the profile is practically unchanged.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
578. A second-order stochastic dominance portfolio efficiency measure
- Creator:
- Kopa, Miloš and Chovanec, Petr
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- stochastic dominance, CVaR, and SSD portfolio efficiency measure
- Language:
- English
- Description:
- In this paper, we introduce a new linear programming second-order stochastic dominance (SSD) portfolio efficiency test for portfolios with scenario approach for distribution of outcomes and a new SSD portfolio inefficiency measure. The test utilizes the relationship between CVaR and dual second-order stochastic dominance, and contrary to tests in Post \cite{Post} and Kuosmanen \cite{Kuosmanen}, our test detects a dominating portfolio which is SSD efficient. We derive also a necessary condition for SSD efficiency using convexity property of CVaR to speed up the computation. The efficiency measure represents a distance between the tested portfolio and its least risky dominating SSD efficient portfolio. We show that this measure is consistent with the second-order stochastic dominance relation. We find out that this measure is convex and we use this result to describe the set of SSD efficient portfolios. Finally, we illustrate our results on a numerical example.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
579. A segmentation method to handwritten word recognition
- Creator:
- Senouci, Mohamed, Liazid, Abdelkrim, Beghdadi, Hadj Ali, and Benhamamouch , Djilali
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Pattern recognition, segmentation, neural networks, and handwritten word
- Language:
- English
- Description:
- This paper presents a segmentation technique to handwritten word recognition. This technique implements an algorithm based on an analytical approach. It uses a letter sweeping procedure with a step equal to the Euclidean distance between an established reference index and the entity (the alphabet letter). Then a dissociation of this entity is achieved when this distance will reach a rate of 80%. Our experience about this segmentation technique gives a rate of 81.05% of recognition. A neural multi-layer perceptron classifier confirms the extracted segment. This procedure is successively repeated from the beginning until the end of the word. A concatenation technique is finally used to the word reconstitution.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
580. A Self Organizing Map Based Approach for Congestion Avoidance in Autonomous IP Networks
- Creator:
- Yelbasi, Özen and Germen, Emin
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Self Organizing Map, congestion avoidance, random early detection, and drop tail
- Language:
- English
- Description:
- This work presents a Self Organizing Map (SOM) based queue management approach against congestion in autonomous Internet Protocol (IP) networks. The new queue management approach is proposed with consideration to the pros and cons of two well-known queue management algorithms: Random Early Detection (RED) and Drop Tail (DT). At the beginning of this study, RED and DT are compared by observing their effects on two important indicators of congestion: end-to-end delay and delay variation. This comparison reveals that the performances of RED and DT vary according to the level of global congestion: under low congestion conditions, when packet losses caused by congestion are unlikely, DT outperforms RED; while under high congestion, RED is superior to DT. The SOM based approach takes into account the variations in the global congestion levels and makes decisions to optimise congestion avoidance. A centralized observation unit is designed for monitoring global congestion levels in autonomous IP networks. A traffic flow is generated between each router and the observation unit so as to follow the changes in the global congestion level. For this purpose, IP routers are specialized to send packets carrying queue length information to the observation unit. A SOM based decision mechanism is used by the observation unit, to make predictions on the future congestion behavior of the network and inform the routers. Routers use this information to update their congestion avoidance behavior, as their ability to update their RED parameters is enhanced by the congestion notifications sent by the observation unit. In this work, multiple simulations are undertaken in order to test the performance of the proposed SOM-based method. A considerable improvement is observed from the point of view of end-to-end delays and delay variations, by comparison with DT and RED as used in recent IP networks.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public