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552. A bound on the $k$-domination number of a graph
- Creator:
- Volkmann, Lutz
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- domination, $k$-domination number, and $P_4$-free graphs
- Language:
- English
- Description:
- Let $G$ be a graph with vertex set $V(G)$, and let $k\ge 1$ be an integer. A subset $D \subseteq V(G)$ is called a {\it $k$-dominating set} if every vertex $v\in V(G)-D$ has at least $k$ neighbors in $D$. The $k$-domination number $\gamma _k(G)$ of $G$ is the minimum cardinality of a $k$-dominating set in $G$. If $G$ is a graph with minimum degree $\delta (G)\ge k+1$, then we prove that $$\gamma _{k+1}(G)\le \frac {|V(G)|+\gamma _k(G)}2.$$ In addition, we present a characterization of a special class of graphs attaining equality in this inequality.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
553. A British view of the Czech right
- Creator:
- Gjuričová, Adéla
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- English
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
554. A broad prospective on fuzzy transforms: From gauging accuracy of quantity estimates to gauging accuracy and resolution of measuring physical fields
- Creator:
- Kreinovich , Vladik and Perfilieva, irina
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Fuzzy transform, interval uncertainty, interval computations, and Hausforff metric
- Language:
- English
- Description:
- Fuzzy transform is a new type of function transforms that has been successfully used in different applications. In this paper, we provide a broad prospective on fuzzy transform. Specifically, we show that fuzzy transform naturally appears when, in addition to measurement uncertainty, we also encounter another type of localization uncertainty: that the measured value may come not only from the desired location x, but also from the nearby locations.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
555. A calibration-free evapotranspiration mapping technique for spatially-distributed regional-scale hydrologic modeling
- Creator:
- Szilágyi, József and Kovács, Ákos
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- spatially distributed evapotranspiration, complementary relationship of Evaporation, MODIS data, priestorové rozdelenie evapotranspirácie, komplementárny vzťah pre evapotranspiráciu, and údaje MODIS
- Language:
- Slovak
- Description:
- Monthly evapotranspiration (ET) rates over Hungary for 2000-2008 are mapped at a spatial scale of about 1 km with the help of MODIS daytime land surface temperature as well as sunshine duration, air temperature and humidity data. Mapping is achieved by a linear transformation of MODIS daytime land surface temperature values employing the complementary relationship of evaporation. Validation of the ET rates has been performed at spatial scales spanning almost three magnitudes from a few hundred meters to about a hundred kilometers employing eddy-covariance (EC) measurements and catchment water balance closures. Typically the unbiased ET estimates are within 15 % of EC values at a monthly basis, within 7 % at an annual, and within only a few percent at a multi-year basis. The ET estimates yield an especially remarkable match (relative error of 0.2 %, R2 = 0.95) with high-tower EC measurements at a monthly basis. The spatial distribution of the ET estimates confirm earlier, complex regional hydrologic model results and observations as well as yields a perfect estimate of the country’s precipitation recycling index (the ratio of the multi-year mean ET and precipitation rates spatially aggregated for the whole country) of 89.2 % vs an observed value of 89.6 %. The CREMAP method is very simple, easy to implement, requires minimal data, calibration-free, and works accurately when conditions for the complementary relationship are met. and Pomocou údajov ročlenených podľa MODIS (moderate resolution imaging spectroradiometer), s využitím dennej povrchovej teploty, trvania slnečného svitu, teploty vzduchu a jeho vlhkosti boli zostrojené mapy mesačnej evapotranspirácie (ET) Maďarska pre roky 2000-2008 s priestorovým rozlíšením približne 1 km. Mapovanie bolo zrealizované lineárnou transformáciou MODIS dennej teploty povrchu s uvážením doplňujúceho vzťahu pre evapotranspiráciu CR, navrhnutou Bouchetom (1963). Výsledky dosiahnuté touto metódou boli verifikované v priestorovej mierke pokrývajúcej tri rády od niekoľkých stoviek metrov po stovky kilometrov, použijúc merania metódou pulzácií (eddy covariance, EC), a bilanciou vody v koncovom profile povodí. Typicky, hodnoty ET sú v medziach 15 % mesačných hodnôt EC a 7 % ročných hodnôt a len v medziach niekoľkých percent viacročných hodnôt evapotranspirácie, ktoré boli určené inými metódami. Hodnoty ET sú v dobrej zhode s výsledkami meraní ET na vysokej veži metódou EC (relatívna chyba 0.2 %, R2 = 0,95). Priestorové rozdelenia vypočítaných hodnôt ET potvrdzujú predchádzajúce výsledky modelovania regionálnymi modelmi, ako aj hodnoty indexu recyklácie zrážok krajiny (precipitation recycling index), čo je pomer mnohoročnej priemernej ET a zrážok agregovaných v krajine, s hodnotou 89,2 % vs pozorovaná hodnota 89,6 %. Metóda CREMAP je jednoduchá, ľahko implementovateľná, vyžaduje minimum vstupných hodnôt, nie je ju potrebné kalibrovať a keď sú splnené podmienky jej použiteľnosti, je aj dostatočne presná.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
556. A cancellative amenable ascending union of nonamenable semigroups
- Creator:
- John
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- amenability, semigroups, and ascending union
- Language:
- English
- Description:
- We construct an example of a cancellative amenable semigroup which is the ascending union of semigroups, none of which are amenable.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
557. A canonical directly infinite ring
- Creator:
- Petrich, Mario and Silva, Pedro V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- directly finite rings and matrix rings
- Language:
- English
- Description:
- Let $\mathbb N$ be the set of nonnegative integers and $\mathbb Z$ the ring of integers. Let $\mathcal B$ be the ring of $N \times N$ matrices over $\mathbb Z$ generated by the following two matrices: one obtained from the identity matrix by shifting the ones one position to the right and the other one position down. This ring plays an important role in the study of directly finite rings. Calculation of invertible and idempotent elements of $\mathcal B$ yields that the subrings generated by them coincide. This subring is the sum of the ideal $\mathcal F$ consisting of all matrices in $\mathcal B$ with only a finite number of nonzero entries and the subring of $\mathcal B$ generated by the identity matrix. Regular elements are also described. We characterize all ideals of $\mathcal B$, show that all ideals are finitely generated and that not all ideals of $\mathcal B$ are principal. Some general ring theoretic properties of $\mathcal B$ are also established.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
558. A canonical genetic algorithm for likelihood estimator of first order moving average model parameter
- Creator:
- Hussain , Basa'd Ali and Al-Dabbagh , Rawa'a Dawoud
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- MA (1), moving average model, likelihood function, moment estimation, canonical genetic algorithm, deterministic selection, two point mutation, and (MSE) mean square Error
- Language:
- English
- Description:
- The increasing availability of computing power in the past two decades has been used to develop new techniques for optimizing the solution of estimation problem. Today's computational capacity and the widespread availability of computers have enabled the development of a new generation of intelligent computing techniques, such as the algorithm of our interest. This paper presents a new member of the class of stochastic search algorithms (known as Canonical Genetic Algorithm "CGA") for optimizing the maximum likelihood function ln (L(θ, σa2 )) of the first order moving average MA(1) model. The presented strategy is composed of three main steps: recombination, mutation, and selection. The experimental design is based on simulating the CGA with different values of (θ), and sample size n. The results are compared with those of moment method. Based on MSE value obtained from both methods, one can conclude that CGA can give estimators (\hat \theta) for MA(1) parameter which are good and more reliable than those estimators obtained by moment method.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
559. A Cantor-Bernstein theorem for $\sigma$-complete MV-algebras
- Creator:
- de Simone, Anna , Mundici, Daniele , and Navara, Mirko
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Cantor-Bernstein theorem, MV-algebra, boolean element of an MV-algebra, partition of unity, direct product decomposition, and $\sigma $-complete MV-algebra
- Language:
- English
- Description:
- The Cantor-Bernstein theorem was extended to $\sigma $-complete boolean algebras by Sikorski and Tarski. Chang’s MV-algebras are a nontrivial generalization of boolean algebras: they stand to the infinite-valued calculus of Łukasiewicz as boolean algebras stand to the classical two-valued calculus. In this paper we further generalize the Cantor-Bernstein theorem to $\sigma $-complete MV-algebras, and compare it to a related result proved by Jakubík for certain complete MV-algebras.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
560. A catalogue of eclipsing binaries in fields of open clusters
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public