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Wyszukujesz frazę "Descent" wg kryterium: Temat


Tytuł:
Semi-Browder operators and perturbations
Autorzy:
Rakočević, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/1220263.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
ascent
descent
semi-Fredholm
Opis:
An operator in a Banach space is called upper (resp. lower) semi-Browder if it is upper (lower) semi-Fredholm and has a finite ascent (resp. descent). An operator in a Banach space is called semi-Browder if it is upper semi-Browder or lower semi-Browder. We prove the stability of the semi-Browder operators under commuting Riesz operator perturbations. As a corollary we get some results of Grabiner [6], Kaashoek and Lay [8], Lay [11], Rakočević [15] and Schechter [16].
Źródło:
Studia Mathematica; 1997, 122, 2; 131-137
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The buffered optimization methods for online transfer function identification employed on DEAP actuator
Autorzy:
Bernat, Jakub
Kołota, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/27322621.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Stochastic Gradient Descent
ADAM
AMSGrad
DEAP
system identification
Opis:
Identification plays an important role in relation to control objects and processes as it enables the control system to be properly tuned. The identification methods described in this paper use the Stochastic Gradient Descent algorithms, which have so far been successfully presented in machine learning. The article presents the results of the Adam and AMSGrad algorithms for online estimation of the Dielectric Electroactive Polymer actuator (DEAP) parameters. This work also aims to validate the learning by batch methodology, which allows to obtain faster convergence and more reliable parameter estimation. This approach is innovative in the field of identification of control systems. The researchwas supplemented with the analysis of the variable amplitude of the input signal. The dynamics of the DEAP parameter convergence depending on the normalization process was presented. Our research has shown how to effectively identify parameters with the use of innovative optimization methods. The results presented graphically confirm that this approach can be successfully applied in the field of control systems.
Źródło:
Archives of Control Sciences; 2023, 33, 3; 565--587
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Convergence Analysis of Inverse Iterative Neural Networks with L₂ Penalty
Autorzy:
Wen, Y.
Wang, J.
Huang, B.
Zurada, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/108754.pdf
Data publikacji:
2016
Wydawca:
Społeczna Akademia Nauk w Łodzi
Tematy:
neural networks
gradient descent
inverse iterative
monotonicity
regularization
convergence
Opis:
The iterative inversion of neural networks has been used in solving problems of adaptive control due to its good performance of information processing. In this paper an iterative inversion neural network with L₂ penalty term has been presented trained by using the classical gradient descent method. We mainly focus on the theoretical analysis of this proposed algorithm such as monotonicity of error function, boundedness of input sequences and weak (strong) convergence behavior. For bounded property of inputs, we rigorously proved that the feasible solutions of input are restricted in a measurable field. The weak convergence means that the gradient of error function with respect to input tends to zero as the iterations go to infinity while the strong convergence stands for the iterative sequence of input vectors convergence to a fixed optimal point.
Źródło:
Journal of Applied Computer Science Methods; 2016, 8 No. 2; 85-98
1689-9636
Pojawia się w:
Journal of Applied Computer Science Methods
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
“The way up is the way down”: Curzio Malaparte’s “Il Cristo Proibito” and Krzysztof Kieślowski’s “Three Colours: Red”
Autorzy:
Coates, Paul
Powiązania:
https://bibliotekanauki.pl/articles/923218.pdf
Data publikacji:
2019-03-25
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
doubling
judgment
fraternité
Christianity
revenge
descent into Hell
Opis:
The statement ‘the way up is the way down’ may imply that the spiritual way to perfection lies through humility. It may however also apply to the physical world that is the source of such spiritual metaphors, and within which the actions play out of fictional characters who themselves serve as metaphors for real ones. I will argue that both meanings apply to both of these films, with a comparison between the two films enabling one to employ Malaparte’s explicit prohibition of a Christ-like position to make apparent a similar prohibition that is only implicit in Kieślowski’s film. Such physical movements provide an appropriate topography for the concern with judgment, knowledge, revenge, isolation and humiliation embodied in the male protagonists of the two films. In each case, the protagonists’ eventual divestment from programmes of judgment and revenge may be related to the prohibition Malaparte formulates explicitly: that upon human re-enactment of the Christ-like position that is the one of judgment. Here a destructive and self-destructive movement downwards, in the sense of dehumanization and extreme isolation, is countered eventually by a downward one that, in fact, leads upwards through an embrace of the humiliation of inaction. The paper examines various ways in which the object of both texts is to rediscover a ‘we’ that is rather one of solidarity than complicity.
Źródło:
Images. The International Journal of European Film, Performing Arts and Audiovisual Communication; 2018, 24, 33; 47-59
1731-450X
Pojawia się w:
Images. The International Journal of European Film, Performing Arts and Audiovisual Communication
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the influence of helicopter descent velocity changes on the phenomenon of vortex ring state
Autorzy:
Grzegorczyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/102235.pdf
Data publikacji:
2013
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
helicopter
Vortex Ring State (VRS)
vertical descent
numerical analysis
CFD
Opis:
The paper presents the results of a numerical aerodynamic analysis whose purpose was to determine the influence of the rate of descent on the vortex ring state (VRS). This phenomenon occurs for an appropriate combination of induced velocity and the velocity of the incoming airstream from the bottom. The rates of change of velocities delimit dangerous areas of flight. The simulations were performed using FLUENT software and the geometry of helicopter W-3 „Sokół”.
Źródło:
Advances in Science and Technology. Research Journal; 2013, 7, 17; 35-41
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the effect of the descent rate of a helicopter in the Vortex Ring conditions
Autorzy:
Surmacz, K.
Kowaleczko, G.
Powiązania:
https://bibliotekanauki.pl/articles/248016.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Vortex Ring State
helicopter descent
computational fluid dynamics
flow simulations
Opis:
One of the limiting factors for a helicopter operation is the Vortex Ring State (VRS). This aerodynamic phenomenon, known as the VRS or “Settling with Power”, is characterized by the formation of circulating air stream moving along a ring shaped track around the main rotor of a helicopter. Conditions, conducive to development of the vortex ring state, occur in the vertical or nearly vertical descent. This leads to decrease in thrust and thus rapidly increasing the rate of descent. This phenomenon occurs for an appropriate combination of induced velocity and the velocity of the stream of airflow from the bottom to the rotor. The rates of change of velocities delimit dangerous areas of flight. The objective of this work was to investigate the influence of the descent rate of a helicopter on the vortex ring formation process and determinants of the occurrence of vortex rings. For better understanding of the nature of this state, a computational method was applied. Series of three-dimensional (3D) unsteady analysis was carried out using Computational Fluid Dynamics tools (CFD). Simulations were realized using geometry and performance of the W-3 “Sokol” helicopter. The paper presents results of a helicopter operation in axial and non-axial descent conditions. Three calculation cases of vertical flight of a helicopter with different rates of velocity changes were considered. A simulation of non-axial descent was based on the measured flight test data for the W-3 helicopter. The results provide information about the changing nature of the flow in the course of the movement of a helicopter and show the influence of the rate of descent during initiation on the development of VRS. Results of the calculations provide guidelines for helicopter pilots.
Źródło:
Journal of KONES; 2016, 23, 1; 345-352
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the axiomatic theory of spectrum II
Autorzy:
Mbekhta, M.
Müller, V.
Powiązania:
https://bibliotekanauki.pl/articles/1287569.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
spectral mapping theorem
ascent
descent
semiregular operators
quasi-Fredholm operators
Opis:
We give a survey of results concerning various classes of bounded linear operators in a Banach space defined by means of kernels and ranges. We show that many of these classes define a spectrum that satisfies the spectral mapping property.
Źródło:
Studia Mathematica; 1996, 119, 2; 129-147
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximate relaxed descent method for optimal control problems
Autorzy:
Chryssoverghi, I.
Coletsos, J.
Kokkinis, B.
Powiązania:
https://bibliotekanauki.pl/articles/206679.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dyskretyzacja
kontrola relaksacyjna
sterowanie optymalne
descent method
discretization
optimal control
relaxed controls
Opis:
We consider an optimal control problem for systems governed by ordinary differential equations with control constraints. Since no convexity assumptions are made on the data, the problem is reformulated in relaxed form. The relaxed state equation is discretized by the implicit trapezoidal scheme and the relaxed controls are approximated by piecewise constant relaxed controls. We then propose a combined descent and discretization method that generates sequences of discrete relaxed controls and progressively refines the discretization. Since here the adjoint of the discrete state equation is not defined, we use, at each iteration, an approximate derivative of the cost functional defined by discretizing the continuous adjoint equation and the integral involved by appropriate trapezoidal schemes. It is proved that accumulation points of sequences constructed by this method satisfy the strong relaxed necessary conditions for optimality for the continuous problem. Finally, the computed relaxed controls can be easily approximated by piecewise constant classical controls.
Źródło:
Control and Cybernetics; 2001, 30, 4; 385-404
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beginnings of the Józef Piłsudski Institute in New York (1943-1956)
Autorzy:
Langowski, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/653698.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Historii im. Tadeusza Manteuffla PAN w Warszawie
Tematy:
Józef Piłsudski Institute in New York
KNAPP
National Committee of Americans of Polish Descent
Opis:
Józef Piłsudski Institute was founded in New York, July 4, 1943. The main aim was to maintain constant and independent scientific research facility dealing not only with collecting and organizing historical documents, but also with popularizing unadulterated knowledge about Poland and its recent history. From its earliest days the Institute was based on financial support granted by Polish activists and on membership fees, as well as on larger donations from some members. Since the late forties, when KNAPP activity slowly began to fade, actions and statements of people associated with the Institute were regarded as guidelines for independence environments. These people formed very cohesive environment, being faithful to Piłsudski heritage, negated any compromises with regard to Polish independence. It was strongly anticommunist rejecting all contacts with PRL institutions. Thanks to the energetic work of people connected with the facility rapidly grew both archival and library collections. In 1949 the collection in the library had grown to 2500 books, periodicals reached up to 800 titles. To the library came valuable Polish diplomatic archives, collections of different personalities, as well as documents showing the huge effort of organizations of Poles, who after the end of the war were on the territory of West Germany.
Źródło:
Studia z Dziejów Rosji i Europy Środkowo-Wschodniej; 2012, 47
2353-6403
1230-5057
Pojawia się w:
Studia z Dziejów Rosji i Europy Środkowo-Wschodniej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing properties of an inertial dynamical system with geometric damping : link with proximal methods
Autorzy:
Attouch, H.
Bolte, J.
Redont, P.
Powiązania:
https://bibliotekanauki.pl/articles/205719.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dynamical systems in optimization
entropic methods in optimization
proximal regularization method
steepest descent method
Opis:
The second-order dynamical system x + [alpha]x + Beta[...] = 0, alpha > 0, Beta > 0, where the Hessian [...]Phi(x) acts as a geometric damping, is introduced, mainly in view of the minimization of [Phi]. Minimizing [Phi] is a problem equivalent to the minimization of the functional [Psi]a,b(x, y) = 1/b^2Phi(x) + 1/2|ax + by|^2, a > 0, b > 0. The latter naturallv appears in the proximal regularization of Phi ; it may also be viewed as an energy. The continuous steepest descent method applied to [Psi]a,b yields a first-order system, which proves to he equivalent to the above-mentioned second-order system, when [Phi] is of class [C^2].
Źródło:
Control and Cybernetics; 2002, 31, 3; 643-657
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Finite Termination Property of an Algorithm for Solving the Minimum Circumscribed Ball Problem
Autorzy:
Gläser, Andreas
Grossman, Christian
Lunze, Ulrich
Powiązania:
https://bibliotekanauki.pl/articles/1373551.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
minimum circumscribed
maximum inscribed
minimum zone
geometrical form elements
coordinate measuring
mini–max problem
steepest
descent
Opis:
In this paper basic mathematical tasks of coordinate measurement are briefly described and a modified optimization algorithm is proposed. Coordinate measurement devices generate huge data set and require adapted methods to solve related mathematical problems in real time. The proposed algorithm possesses a simplified step size rule and finds the solution of the minimum circumscribed ball fitting after only a finite number The iteration is of the steepest descent type applied to the related distance function. But, in contrast to standard algorithms it uses a modified step size rule that takes into account the specific properties of the occurring objective function. This small difference in the code improves the performance of the algorithm and it enables real time use of the proposed method in coordinate measurement machines. The efficiency of the prosed algorithm will be illustrated by some typical examples.
Źródło:
Schedae Informaticae; 2012, 21; 127-139
0860-0295
2083-8476
Pojawia się w:
Schedae Informaticae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Continuous descent approach : noise test for Warsaw international airport
Autorzy:
Gągorowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/247891.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Continuous Descent Approach
CDA concept
aircraft type
air transport
demonstration test
noise pollution
noise environmental protection
Opis:
The noise generated by aircraft during departure and arrival flight operations continues to be significant problem at most major airports. Environmental impacts due to aviation operations in the vicinity of airports have become a serious concern to the community. A variety of techniques can be employed to reduce the noise impacts of aircraft. Continuous Descent Approach (CDA) is the new promising technique, which can significantly reduce noise impact by keeping aircraft higher and at lower engine thrust for longer by eliminating the level segments in conventional "step down" approaches. These procedures (implemented in different ways) are fixed routes that are vertically optimized. With the changing traffic, conditions and variable noise abatement rules the benefits of CDA operations are not yet fully realized. Actually, at many airports, CDA techniques are implemented for environmental improvements. This article presents the concept of optimized CDA. The modified flight procedure has been shown in measurement and analysis for Warsaw International Airport example. In this demonstration test, the procedure was shown to reduce the A-weighted noise level for the selected location along the flight path for different aircraft. Depending on aircraft type, the noise benefit from a CDA compared to a conventional approach was up to about 9.5 decibels (this change is noticeable to the human ear). Measurements have shown that Continuous Descent Approach have the potential for significant environmental benefits including reductions in noise.
Źródło:
Journal of KONES; 2012, 19, 2; 167-174
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In vitro culture of white lupin embryos as a stage for SSD technique
Autorzy:
Ogrodowicz, Piotr
Mikołajczak, Krzysztof
Kuczyńska, Anetta
Kaczmarek, Zygmunt
Ćwiek-Kupczyńska, Hanna
Surma, Maria
Adamski, Tadeusz
Święcicki, Wojciech
Barzyk, Paweł
Trzeciak, Renata
Kempa, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2148491.pdf
Data publikacji:
2021-03-31
Wydawca:
Instytut Uprawy Nawożenia i Gleboznawstwa – Państwowy Instytut Badawczy
Tematy:
embryo development
single seed descent technique
survival rate
temperature regimes
type of growth
white lupin
Opis:
White lupin is an important source of proteins, the content of which amounts to 36–40% in its seeds. Breeding of new varieties usually takes several years. The present study aimed to shorten the breeding cycle by applying the single-seed descent technique together with in vitro culture of embryos dissected from immature seeds. The effects of temperature on embryo development were studied in indeterminate vs. determinate varieties in in vitro culture using the following temperature regimes:(1) 8 °C; (2) 16 °C in the first week, then 8 °C; (3) 20 °C in the first week, then 20/18 °C; and (4) 16 °C throughout the culture period. The embryos were cultured on the standard Murashige and Skoog medium. The observed growth rate of plantlets as well as the survival of plants ex vitro showed that at lower temperatures (8–16 °C) the plants developed slowly, but their ex vitro survival rate was higher compared to those grown at a higher temperature (20 °C). In addition, the results indicated that the in vitro embryo development rate of determinate varieties is significantly lower than that of indeterminate varieties.
Źródło:
Polish Journal of Agronomy; 2021, 44; 9-14
2081-2787
Pojawia się w:
Polish Journal of Agronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary results of in vitro culture of pea and lupin embryos for the reduction of generation cycles in single seed descent technique
Autorzy:
Surma, M.
Adamski, T.
Swiecicki, W.
Barzyk, P.
Kaczmarek, Z.
Kuczynska, A.
Krystkowiak, K.
Mikolajczak, K.
Ogrodowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/56430.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
in vitro culture
pea
lupin
embryo
reduction
single seed descent technique
Lupinus angustifolius
Lupinus luteus
Pisum sativum
Opis:
The aim of the studies was to establish in vitro conditions for the culture of pea and lupin embryos as the first step in the development of an in vitro assisted single seed descent technique for the attainment of homozygous populations. Materials for the study included of pea, and narrow-leafed and yellow lupin cultivars. Embryos dissected from mature but still-green seeds were cultured in vitro on two modified MS media and under three temperature regimes. Shoot and root lengths of regenerated plants were measured after 7, 14 and 21 days of culture. For pea plants full-strength MS medium with 4 g l−1 agar and temperature 22/ 20°C (day/night) appeared to be the most conducive to shoot and root development, whereas for lupin plants lower temperatures were more propitious: 12°C in the dark for narrow-leafed lupin and 16/ 12°C (day/night) for yellow lupin. Almost all the cultured embryos developed into plants, but not all the regenerated plants survived acclimation to ex vitro conditions.
Źródło:
Acta Societatis Botanicorum Poloniae; 2013, 82, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł

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