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Tytuł:
Weak compactness in the space of operator valued measures $M_ba(Σ,(X,Y))$ and its applications
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729361.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
space of operator valued measures
weak compactness
semigroups of bounded linear operators
optimal structural control
Opis:
In this note we present necessary and sufficient conditions characterizing conditionally weakly compact sets in the space of (bounded linear) operator valued measures $M_{ba}(Σ,(X,Y))$. This generalizes a recent result of the author characterizing conditionally weakly compact subsets of the space of nuclear operator valued measures $M_{ba}(Σ,₁(X,Y))$. This result has interesting applications in optimization and control theory as illustrated by several examples.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2011, 31, 2; 231-247
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vector and operator valued measures as controls for infinite dimensional systems: optimal control
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729468.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
evolution equations
Banach spaces
operator valued measures
strong operator topology
existence of solutions
optimal control
Opis:
In this paper we consider a general class of systems determined by operator valued measures which are assumed to be countably additive in the strong operator topology. This replaces our previous assumption of countable additivity in the uniform operator topology by the weaker assumption. Under the relaxed assumption plus an additional assumption requiring the existence of a dominating measure, we prove some results on existence of solutions and their regularity properties both for linear and semilinear systems. Also presented are results on continuous dependence of solutions on operator and vector valued measures, and other parameters determining the system which are then used to prove some results on control theory including existence and necessary conditions of optimality. Here the operator valued measures are treated as structural controls. The paper is concluded with some examples from classical and quantum mechanics and a remark on future direction.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2008, 28, 1; 95-131
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient flow simulation, analysis and protection of pipeline systems
Autorzy:
El-Hazek, Alaa N.
Ahmed, Menna F.
Badawy, Neveen Abdel-Mageed
Powiązania:
https://bibliotekanauki.pl/articles/1844407.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
air vessel
Bentley HAMMER model
surge tank
unsteady flow
vacuum breaker valve
water hammer
water turbidity
Opis:
This paper investigated the problems and impacts of transient flow in pipeline systems due to pump power failure. The impact of different protection devices was presented to assure surge protection for the pipeline system. A model via Bentley HAMMER V8.0 Edition was employed to analyse and simulate hydraulic transients in the pipeline system, and protection alternatives were studied. Surge protection included using only an air vessel, using an air vessel and two surge tanks, and employing five air vessels and vacuum breaker. The obtained results for pressures, heads, and cavitation along the pipeline system were graphically presented for various operating conditions. Using five air vessels with vacuum breaker valve as surge protection proved to be more effective and economical against pump power failure. Changing the flow density did not have a significant impact on the pressures. For protection with an air vessel; it was concluded that the value 40% of the original diameter for inlet pipe diameter of air vessel, and the value of 2/3 of original pipe diameter were critical values for the transient pressures. Cast iron pipes proved to be the best pipe material for all studied volumes of the air vessel. For protection with an air vessel and two surge tanks; as the inlet pipe diameters increased the maximum pressures increased and the minimum pressures decreased. Regression analyses were performed obtaining equations to predict the pressures according to the inlet pipe diameter, the area of surge tank, and the pipe diameter.
Źródło:
Journal of Water and Land Development; 2020, 47; 47-60
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological dual of $B_∞(I, ₁(X,Y))$ with application to stochastic systems on Hilbert space
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729390.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
representation theory
topological dual
finitely additive operator-valued measures
polish space
Hilbert space
stochastic systems
structural control
uncertainty abatement
Opis:
In this paper, we prove that the topological dual of the Banach space of bounded measurable functions with values in the space of nuclear operators, furnished with the natural topology, is isometrically isomorphic to the space of finitely additive linear operator-valued measures having bounded variation in a Banach space containing the space of bounded linear operators. This is then applied to a stochastic structural control problem. An optimal operator-valued measure, considered as the structural control, is to be chosen so as to minimize fluctuation (volatility). Both existence of optimal policy and necessary conditions of optimality are presented including a conceptual algorithm.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2009, 29, 1; 67-90
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical model to determine the Porosity and refractive index of porous silicon type-n by using Atomic force microscope
Autorzy:
Abdulridha, Wasna'a M.
Abd, Ahmed N.
Dawood, Mohammed O.
Powiązania:
https://bibliotekanauki.pl/articles/1193012.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Atomic Force Microscope
Porous silicon
n-PS
porosity
refractive index
thickness
Opis:
Porous silicon (PS) layer was produced by photochemical etching process at (5, 7, 10, 12 and 15) etching time and 7 mA/cm2 current density then after investigation by Atomic Force Microscope (AFM) the thickness of PS layer from about 3.4 µm to 15.8 µm was determined. The surface of porous silicon is formed from small pyramids with porous structure, where the porosity of n-PS is from ≈ (32-72%). Porous silicon layer formed on the silicon substrates by photochemical etching contains also the nanopores with diameter about (16.41-42) nm in current density (7mA/cm2). The porosity and thickness was determined from AFM results and compared with the result from the usually measured porosity and thickness through a gravimetric method we found that the values of porosity and thickness calculated from two methods are approximately similar to each other with few difference, the influence of structure changes on optical properties such as refractive index, which decreases exponentially with porosity.
Źródło:
World Scientific News; 2016, 28; 29-40
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Treatment of Hospital Wastewater Using Electrocoagulation Process – Analysis by Response Surface Methodology
Autorzy:
Salah Al-Shati, Ahmed
Alabboodi, Khalid O.
Shamkhi, Hassan A.
Abd, Zahraa N.
Emeen, Sara I. Mohammed
Powiązania:
https://bibliotekanauki.pl/articles/2202336.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
electrocoagulation
RSM
response surface methodology
COD removal
Opis:
Electrocoagulation (EC) can be defined a method utilized to remove pollutants from wastewater by applying an electric current to sacrificial electrodes. Many experimental variables like NaCl content (0–4 g/l), current density (5–25 mA/cm2), time (30–90 mins), and pH (4–10) that influence the removal efficiency regarding COD were considered. In the presented research, three distinct configurations related to electrodes, i.e. Al-Al, Fe-Al, and Fe-Fe, have been utilized to determine which was the most effective. RSM depending on BBD was utilized for optimizing various operational parameters with regard to HWW by use of EC. Maximum COD removal (97.9%) was reached at Fe-Al electrodes, NaCl (3.2 g/l), current density (24.7 mA/cm2), time (81.7 mins), and pH (7.4). COD removal (91.3%) was achieved at the Al-Al electrodes, NaCl (3.8 g/l), current density(23.5 mA/cm2), time-86.3 min, and Ph (7.7). At the Fe-Fe electrodes, the removal of COD (89.5%) was obtained at NaCl (2.3 g/l), current density (24.6 mA/cm2), pH 8.5, and time (86.9 min). This indicates that EC could remove pollutants from different types of wastewaters under many operating parameters and with arrangements of electrodes.
Źródło:
Journal of Ecological Engineering; 2023, 24, 1; 260--276
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Different Processing Methods on the Behavior of Minerals Content in Food Products
Autorzy:
Alshallash, Khalid S.
Shahat, Mohamed
Ibrahim, Mohamed I.
Hegazy, Ahmed I.
Hamdy, Ashraf E.
Elnaggar, Ibrahim A.
El-Wahed, Abd El-Wahed N. Abd
Taha, Ibrahim M.
Powiązania:
https://bibliotekanauki.pl/articles/24201608.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
mineral
fruit
processing
canning
dehydration
stewing
Opis:
The goal of the current study was to determine the mineral content of different fruit varieties (Na, K, Ca, P, Mg, Fe, Zn, and Cu), as well as the effects of various processing methods (such as canning, drying, stewing, syrup process, and concentration of juices). All tested fruits that were subjected to various types of processing were exposed to a degree of mineral loss, varying from very little to high reduction. However, it still retains its nutritional value. All fig products have the greatest levels of most tested minerals, compared to other processed fruit products, particularly P and Fe. In turn, orange products supply higher quantities of Ca. On the other hand, apricot products have a comparable value of other minerals with those found in fig and orange products. Among canned juices, guava had the highest contents of Ca, P, and Fe, while mango scored the first juice as Mg and Zn supplying. Canned apricot halves contain the best amounts of K, Ca, P and Mg than the same products of apple and peach. Among jam products, fig jam has higher amounts of Na, Ca, P, Mg, and Fe than those found in other fruit jams. The concentration of fruit juices by vacuum-heating or dehydration of fruit produced higher mineral retentions than the fruit products that were processed by other techniques. The concentrated orange juice by vacuum-heating processing retained most of the minerals found in raw juice, also dried apricot sheet retained higher minerals than those retained in dehydrated whole apricot.
Źródło:
Journal of Ecological Engineering; 2023, 24, 3; 263--275
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic evolution equations on Hilbert spaces with partially observed relaxed controls and their necessary conditions of optimality
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729524.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
differential equations
Hilbert spaces
relaxed controls
optimal control
necessary conditions of optimality
Opis:
In this paper we consider the question of optimal control for a class of stochastic evolution equations on infinite dimensional Hilbert spaces with controls appearing in both the drift and the diffusion operators. We consider relaxed controls (measure valued random processes) and briefly present some results on the question of existence of mild solutions including their regularity followed by a result on existence of partially observed optimal relaxed controls. Then we develop the necessary conditions of optimality for partially observed relaxed controls. This is the main topic of this paper. Further we present an algorithm for computation of optimal policies followed by a brief discussion on regular versus relaxed controls. The paper is concluded by an example of a non-convex problem which is readily solvable by our approach.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2014, 34, 1; 105-129
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic diffrential equations on Banach spaces and their optimal feedback control
Autorzy:
Ahmed, N.U.
Powiązania:
https://bibliotekanauki.pl/articles/952179.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
stochastic differential equations
Banach spaces
optimal feedback control
objective functionals
Lévy-Prohorov metric
Hausdorff dimension
time-optimal problems
Opis:
In this paper we consider stochastic differential equations on Banach spaces (not Hilbert). The system is semilinear and the principal operator generating a C₀-semigroup is perturbed by a class of bounded linear operators considered as feedback operators from an admissible set. We consider the corresponding family of measure valued functions and present sufficient conditions for weak compactness. Then we consider applications of this result to several interesting optimal feedback control problems. We present results on existence of optimal feedback operators.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2012, 32, 1; 87-109
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Methods Studies in Polymer
Autorzy:
Rahi, Saad Khalid
Hassan, Ehssan Salah
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1190136.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ESCA
polymer
Fluorescence spectra
Excitation wavelength
Opis:
The physico – chemical changes induced in polymers following to radiation can be studied by a range of spectroscopic techniques. Recent developments in instrumentation and data analysis procedures in electronic, vibrational and magnetic resonance spectroscopes have provided considerable new insights, into polymer structure and behavior. The applications of these spectroscopic methods in polymer studies are reviewed with emphasis on their utility in investigations of radiation effects on macromolecules
Źródło:
World Scientific News; 2016, 42; 41-53
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Physical Properties of Copper Oxide Thin Films Prepared by Electrolysis Method
Autorzy:
Oudah, Mustafa H.
Mazin, H. Hasan
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1065248.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
copper oxide
drop-casting method
electrolysis
quantum size effect
thin films
Opis:
The aim of this paper is to study the properties of copper oxide thin films prepared by electrolysis method and deposited on glass substrates by drop-casting method at different annealing temperatures. Copper oxide colloidal was successfully prepared by electrolysis method. The X-ray diffraction confirms the polycrystalline structure of the films. Atomic force microscopy shows that the increase in the annealing temperature improves the surface morphology, increases the grain size and removes the cracks. The best optical transmittance was for the film annealed at 200 ºC. The bandgap decreases from 3.35 eV to 3.15 eV as a result of increasing the annealing temperature. The wide bandgap that obtained in this study is due to quantum size effect.
Źródło:
World Scientific News; 2019, 135; 59-70
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimum receiver performance of TH-PPM ultra wideband system in multiple user interference
Autorzy:
Mahfuz, M. U.
Ahmed, K. M.
Rajatheva, N.
Powiązania:
https://bibliotekanauki.pl/articles/308545.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
optimum receiver performance
TH-PPM
ultra wideband
multiple user interference
Opis:
This paper demonstrates optimum receiver performance in terms of bit error rate (BER) for time hopping pulse position modulation (TH-PPM) ultra wideband (UWB) system in multiple user interference environment for indoor radio communication. Equal gain combining and selective gain combining have been demonstrated in terms of ideal RAKE (ARAKE), selective RAKE (SRAKE) and partial RAKE (PRAKE) receiver performances. The recently accepted IEEE 802.15.3a model of the UWB channel has been used to describe UWB propagation in indoor environment. Two channel scenarios named CM-1 and CM-3 for IEEE 802.15.3a channel model have been investigated principally. Finally, this paper concludes with an approximation of equivalence of number of fingers in SRAKE and PRAKE receivers as well as an indication of SNR gains achievable as the RAKE finger number is increased, espe- cially with multiple user interference (MUI), for a 16.6 Mbit/s UWB system.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 4; 77-84
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of ∞-dimensional stochastic systems via generalized solutions of HJB equations
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729348.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
optimal control
stochastic systems
infinite dimension
HJB equation
stationary feedback control
Opis:
In this paper, we consider optimal feedback control for stochastc infinite dimensional systems. We present some new results on the solution of associated HJB equations in infinite dimensional Hilbert spaces. In the process, we have also developed some new mathematical tools involving distributions on Hilbert spaces which may have many other interesting applications in other fields. We conclude with an application to optimal stationary feedback control.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2001, 21, 1; 97-126
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control of systems determined by strongly nonlinear operator valued measures
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729396.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
evolution equations
strongly nonlinear operator valued measures
existence of solutions
regularity properties
optimal control
Opis:
In this paper we consider a class of distributed parameter systems (partial differential equations) determined by strongly nonlinear operator valued measures in the setting of the Gelfand triple V ↪ H ↪ V* with continuous and dense embeddings where H is a separable Hilbert space and V is a reflexive Banach space with dual V*. The system is given by
dx + A(dt,x) = f(t,x)γ(dt) + B(t)u(dt), x(0) = ξ, t ∈ I ≡ [0,T]
where A is a strongly nonlinear operator valued measure mapping Σ × V to V* with Σ denoting the sigma algebra of subsets of the set I and f is a nonlinear operator mapping I × H to H, γ is a countably additive bounded positive measure and the control u is a suitable vector measure. We present existence, uniqueness and regularity properties of weak solutions and then prove the existence of optimal controls (vector valued measures) for a class of control problems.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2008, 28, 1; 165-189
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 44

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