212 results
Search Results
202. Ill-posed abstract Volterra equations
- Author
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Marko Kostić
- Subjects
Well-posed problem ,Subordination (linguistics) ,symbols.namesake ,General Mathematics ,Line (geometry) ,symbols ,Applied mathematics ,Volterra equations ,Volterra integral equation ,Mathematical economics ,Mathematics - Abstract
The study of ill-posed abstract Volterra equations is a recent subject. In this paper, we investigate equations on the line, continue the research of (a, k)-regularized C-resolvent families, subordination principles, abstract semilinear Volterra integrodifferential equations, and provide several illustrative examples.
- Published
- 2013
203. A global transpose-free method with quasi-minimal residual strategy for the Sylvester equations
- Author
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Chuanqing Gu and Ke Zhang
- Subjects
General Mathematics ,Mathematical analysis ,MathematicsofComputing_NUMERICALANALYSIS ,Residual ,Sylvester's law of inertia ,Transpose ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Linear algebra ,Convergence (routing) ,Applied mathematics ,Multiplication ,Reduction (mathematics) ,Sylvester equation ,Mathematics - Abstract
The Sylvester equation has numerous applications in control and system theory, power system, linear algebra, model reduction and signal processing. In the present paper, a global transpose-free quasi- minimal residual method for the Sylvester equations is proposed. The resulting method, with short- term recurrences, does not involve the multiplication with the transpose of the coefficient matrices, and often exhibits smoother convergence behavior than some other existing global methods. Finally, several numerical examples are reported by comparing the proposed method with some global methods.
- Published
- 2013
204. Well-posedness by perturbations of variational-hemivariational inequalities with perturbations
- Author
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Himanshu Gupta, Ching-Feng Wen, and Lu-Chuan Ceng
- Subjects
Class (set theory) ,Inequality ,General Mathematics ,media_common.quotation_subject ,Mathematical analysis ,Banach space ,Extension (predicate logic) ,Metric (mathematics) ,Applied mathematics ,Uniqueness ,Special case ,Well posedness ,media_common ,Mathematics - Abstract
In this paper, we consider an extension of the notion of well-posedness by perturbations, introduced by Zolezzi for a minimization problem, to a class of variational-hemivariational inequalities with perturbations in Banach spaces, which includes as a special case the class of mixed variational inequalities. Under very mild conditions, we establish some metric characterizations for the well-posed variational-hemivariational inequality, and show that the well-posedness by perturbations of a variational-hemivariational inequality is closely related to the well-posedness by perturbations of the corresponding inclusion problem. Furthermore, in the setting of finite-dimensional spaces we also derive some conditions under which the variational-hemivariational inequality is strongly generalized well-posed-like by perturbations.
- Published
- 2012
205. Optimal control for stochastic singular integro-differential Takagi-Sugeno fuzzy system using ant colony programming
- Author
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N. Kumaresan
- Subjects
Quadratic equation ,Exact solutions in general relativity ,Control theory ,General Mathematics ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Applied mathematics ,Fuzzy control system ,Ant colony ,Optimal control ,Differential algebraic equation ,Differential (mathematics) ,Algebraic Riccati equation ,Mathematics - Abstract
In this paper, optimal control for stochastic singular integro-differential Takagi-Sugeno (T-S) fuzzy system with quadratic performance is obtained using ant colony programming (ACP). To obtain the optimal control, the solution of MRDE is computed by solving differential algebraic equation (DAE) using a novel and nontraditional ACP approach. The obtained solution in this method is equivalent or very close to the exact solution of the problem. An illustrative numerical example is presented for the proposed method.
- Published
- 2012
206. A posteriori bounds of approximate solution to variational and quasi-variational inequalities
- Author
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Milojica Jacimovic and Izedin Krnic
- Subjects
Linearization ,General Mathematics ,Variational inequality ,Variational message passing ,Calculus ,Stopping rules ,Applied mathematics ,A priori and a posteriori ,Approximate solution ,Mathematics - Abstract
In this paper we present some bounds of an approximate solution to variational and quasi-variational inequalities. The measures of errors can be used for construction of iterative and continuous procedures for solving variational (quasi-variational) inequalities and formulation of corresponding stopping rules. We will also present some methods based on linearization for solving quasi-variational inequalities.
- Published
- 2011
207. Estimation of a condition number related to A(2)T,S
- Author
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Dijana Mosić
- Subjects
symbols.namesake ,Generalized inverse ,General Mathematics ,Mathematical analysis ,Hilbert space ,symbols ,Applied mathematics ,Condition number ,Mathematics - Abstract
In this paper we get estimation of the absolute condition number a Hilbert space operator, which is related with the outer generalized inverse of a given operator.
- Published
- 2011
208. Dynamics of Gilpin-Ayala competition model with random perturbation
- Author
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Miljana Jovanović and Maja Vasilova
- Subjects
Competition (economics) ,Competition model ,General Mathematics ,Bounded function ,Dynamics (mechanics) ,Applied mathematics ,Random perturbation ,Mathematical economics ,Brownian motion ,Mathematics - Abstract
In this paper we study the Gilpin-Ayala competition system with random perturbation which is more general and more realistic than the classical Lotka-Volterra competition model. We verify that the positive solution of the system does not explode in a finite time. Furthermore, it is stochastically ultimately bounded and continuous a.s. We also obtain certain results about asymptotic behavior of the stochastic Gilpin-Ayala competition model. 2010 Mathematics Subject Classifications. 60H10, 34K50. .
- Published
- 2010
209. Ocena telesne kondicije visokomlečnih krava
- Author
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Vlada Pantelić, Stevica Aleksic, Dušica Ostojić-Andrić, Lj. Sretenovic, G. Grubić, and Ž. Novaković
- Subjects
General Mathematics ,Energy balance ,plodnost ,ocena telesne kondicije ,High yielding ,Body condition score ,zdravlje ,Statistics ,Production (economics) ,ishrana ,Reliability (statistics) ,Dairy cattle ,Mathematics ,fertility ,body condition score ,business.industry ,Applied Mathematics ,bilans energije ,health ,energy balance ,Biotechnology ,proizvodnja ,nutrition ,Body region ,production ,business ,Body condition - Abstract
Problems which relate to production, health and reproduction in herds of high yielding cows very often occur due to insufficient knowledge and monitoring of energy reserves in cow organisms. Many researches and practical experiences in this field indicate significant relation between body condition and achieved results in production. Body condition of heads of cattle in certain stages of production cycle is important parameter of applied nutrition, but also entire technological procedure. In countries with developed cattle production, evaluation of body condition has for several years been main component of production practice on farms. It is considered that condition is very reliable indicator of the nutrition status and energy balance in the organism. Body condition score is subjective and practical method which enables precise assessment of deposited fat in the cow organism by observing and touching previously determined body regions and fields. There is considerable variability of the condition of cows in different stages of production cycle. Body condition of high yielding cows often comes out of the frame of optimal values for certain stage of production cycle. Decrease of production, disorders in health condition and fertility of cows indicate the nature of relation between inadequate body condition and stated problems. Shape and strength of the relation between production results and body condition score confirms its reliability. This is all indication of the need for wider application of this evaluation system. Based on body condition score, beside other important factors in the production cycle, there is realistic possibility to achieve more efficient production of milk from the aspect of energy. Main purpose of this paper was to present how the application of methods for body condition score and its significance for production practice can be functional. Postojeći problemi u proizvodnji mleka, rezultatima reprodukcije i zdravstvenom stanju visokoproizvodnih krava mogu da se dovedu u vezu sa primenjenom tehnologijom ishrane. Važno pitanje u tehnologiji ishrane visokomlečnih krava predstavlja količina raspoložive energije (hrana, depoi masti, mišići) u ključnim fazama proizvodnog ciklusa (period zasušenja i rane laktacije). Deficit energije u kritičnim periodima proizvodnog procesa može da dovede do ozbiljnih poremećaja u proizvodnji, zdravlju i reprodukciji U početnoj fazi proizvodnje mleka najkritičniji je period maksimalne dnevne proizvodnje. Negativan bilans energije najizraženiji je u vrhu laktacije. Visok gubitak energije na račun telesnih rezervi predstavlja veliko opterećenje za metabolizam krava. Obezbeđenje adekvatne količine energije je složen uslov za svaku fazu proizvodnog ciklusa. OTK je subjektivan metod koji vizuelno i opipavanjem vrednuje količinu potkožne telesne masti. OTK je koristan alat za upravljanje mlečnim stadom. Idealna telesna kondicija je rang koji je u funkciji toka i faze laktacije. Procena rezervi energije u organizmu utvrđena preko OTK u osnovi predstavlja hranidbeni status grla vrednovan preko deponovanog masnog tkiva, pri čemu telesni okvir i masa grla imaju sekundaran značaj. Jedan od sistema za OTK krava koji je značajan za praksu je američki Virdžinija sistem modifikovan po Edmodsonu. Sistem za OTK kreiran je u obliku mape (karte) za ocenu visokomlečnih krava. Mapa je precizno pripremljena za svaki telesni region i polje koji se može smatrati važnim u dodeli ukupne OTK krave. Tri velika telesna regiona (slabine, karlica i koren repa) podeljena su osam polja na telu krave (slabine imaju četiri polja; karlica ima tri polja; koren repa ima jedno polje). Svako telesno polje se posebno ocenjuje i koristi kao pokazatelj telesne kondicije. Svako grlo ocenjeno je individualno za promene nivoa ocene duž skale od 1 do 5. Kontinuirano se koristi povećanje od 0,25 delova poena. Ceo sistem OTK funkcioniše sa 17 nivoa u okviru ukupne skale ocena posmatrane u intervalu od minimalne ocene u iznosu 1 i maksimalne u iznosu 5. Ocena 1 pokazuje mršavu kondiciju. Ocena 5 pokazuje izrazito tovnu kondiciju. Svaka faza proizvodnog ciklusa ima svoju optimalnu ocenu. Pod normalnim uslovima krave treba da gube telesnu kondiciju najviše od 4 do 6 nedelja. U skromnim vrednostima telesna kondicija postepeno se vraća u periodu od 7 do 12 nedelje. Krave u prvih od 100 do 120 dana laktacije treba da imaju ocenu između od 2,50 do 3,25. Ocena telesne kondicije od 200 dana laktacije do perioda zasušenja treba da je između 2,75 i 3,50. Ishrana u periodu zasušenja treba da osigura ocenu između 3,25 i 3,50. Mogućnost vrednovanja energetskog (hranidbenog) statusa i efikasnosti ishrane visokomlečnih krava pomoću OTK preporučuje ovaj sistem za praktičnu primenu u tehnološkim programima na govedarskim farmama.
- Published
- 2009
210. Mixed and component wise condition numbers for weighted Moore-Penrose inverse and weighted least squares problems
- Author
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Li Zhao and Jie Sun
- Subjects
Discrete mathematics ,Matrix (mathematics) ,Rank (linear algebra) ,General Mathematics ,Numerical analysis ,Applied mathematics ,Inverse ,Measure (mathematics) ,Scaling ,Moore–Penrose pseudoinverse ,Linear least squares ,Mathematics - Abstract
Condition numbers play an important role in numerical analysis. Classical condition numbers are norm-wise: they measure both input perturbations and output errors with norms. To take into account the relative scaling of data components or a possible sparseness, component-wise condition numbers have been increasingly considered. In this paper, we give explicit expressions for the mixed and component-wise condition numbers for the weighted Moore-Penrose inverse of a matrix A, as well as for the solution and residue of a weighted linear least squares problem ||W 1 2 (Ax-b) ||2 = minv2Rn ||W 1 2 (Av-b) ||2, where the matrix A with full column rank. .
- Published
- 2009
211. On stochastic integrodifferential equations via non-linear integral contractors I
- Author
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Svetlana Janković and Miljana Jovanović
- Subjects
Nonlinear system ,General Mathematics ,Bounded function ,Mathematical analysis ,Applied mathematics ,Uniqueness ,Special case ,Type (model theory) ,Lipschitz continuity ,Computer Science::Computers and Society ,Mathematics - Abstract
The aim of this paper is to study the existence and uniqueness of solutions for a general stochastic integrodifferential equation of the Ito type, by using the concept of non-linear bounded random integral contractors, which includes the Lipschitz condition as a special case. The method applied in this consideration follows partially the basic ideas of the contractor theory introduced earlier by Altman [1, 2] and Kuo [6]. It is also shown that the Lipschitz condition and the condition based on a bounded random integral contractor for the coefficients of the considered equation, in general, cannot be compared.
- Published
- 2009
212. Comparability of partial differential operators and manifold linearity
- Author
-
Raid Al-Momani
- Subjects
Stochastic partial differential equation ,Constant coefficients ,Parametrix ,General Mathematics ,Mathematical analysis ,First-order partial differential equation ,Applied mathematics ,Operator theory ,Hyperbolic partial differential equation ,Fourier integral operator ,Symbol of a differential operator ,Mathematics - Abstract
The comparison of differential operators is a problem that was formulated in sixties by Lars Hormander, it is a part of the theory of partial differential operators with constant coefficients, this problem up to now does not have a complete solution. The urgency of this problem is stipulated by the applications of the solvability theory of differential equations in special spaces of generalized functions. In this paper we prove some results in the manifold linearity of a polynomial, these results play an important role in the comparison of two linear partial differential operators problem.
- Published
- 2006
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