Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "directed graph" wg kryterium: Temat


Tytuł:
Directed forests with application to algorithms related to Markov chains
Autorzy:
Pokarowski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1338687.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
entrywise relative error
directed forest
Matrix Tree Theorem
directed graph
Simulated Annealing
Markov chains
Metropolis algorithm
direct methods for linear systems
nearly completely decomposable Markov chains
aggregation algorithms
nonhomogeneous Markov chains
Markov Chain Tree Theorem
Markov chain Monte Carlo algorithms
Gibbs sampler
Opis:
This paper is devoted to computational problems related to Markov chains (MC) on a finite state space. We present formulas and bounds for characteristics of MCs using directed forest expansions given by the Matrix Tree Theorem. These results are applied to analysis of direct methods for solving systems of linear equations, aggregation algorithms for nearly completely decomposable MCs and the Markov chain Monte Carlo procedures.
Źródło:
Applicationes Mathematicae; 1999, 26, 4; 395-414
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isomorphisms and traversability of directed path graphs
Autorzy:
Broersma, Hajo
Li, Xueliang
Powiązania:
https://bibliotekanauki.pl/articles/743350.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
directed path graph
line digraph
isomorphism
travers-ability
Opis:
The concept of a line digraph is generalized to that of a directed path graph. The directed path graph Pₖ(D) of a digraph D is obtained by representing the directed paths on k vertices of D by vertices. Two vertices are joined by an arc whenever the corresponding directed paths in D form a directed path on k+1 vertices or form a directed cycle on k vertices in D. In this introductory paper several properties of P₃(D) are studied, in particular with respect to isomorphism and traversability. In our main results, we characterize all digraphs D with P₃(D) ≅ D, we show that P₃(D₁) ≅ P₃(D₂) "almost always" implies D₁ ≅ D₂, and we characterize all digraphs with Eulerian or Hamiltonian P₃-graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 2; 215-228
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Undirected and directed graphs with near polynomial growth
Autorzy:
Trofimov, V.
Powiązania:
https://bibliotekanauki.pl/articles/743188.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
vertex-symmetric graph
vertex-symmetric directed graph
near polynomial growth
multivalued mapping
Opis:
The growth function of a graph with respect to a vertex is near polynomial if there exists a polynomial bounding it above for infinitely many positive integers. In the paper vertex-symmetric undirected graphs and vertex-symmetric directed graphs with coinciding in- and out-degrees are described in the case their growth functions are near polynomial.
Źródło:
Discussiones Mathematicae Graph Theory; 2003, 23, 2; 383-391
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The minimum exponent of the primitive digraphs on the given number of arcs
Autorzy:
Rosiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/2050786.pdf
Data publikacji:
2004
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
primitive directed graph
exponent
Frobenius number
Opis:
Primitive digraphs on n vertices, k arcs and girth s are considered. By a(n, k, s) we mean the minimum exponent taken over all such digraphs. We estimate the number a(n, k, s) using the Frobenius number for special values of k and s.
Źródło:
Opuscula Mathematica; 2004, 24, 2; 197-202
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Factoring directed graphs with respect to the cardinal product in polynomial time
Autorzy:
Imrich, Wilfried
Klöckl, Werner
Powiązania:
https://bibliotekanauki.pl/articles/743472.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
directed graphs
cardinal product
graph algorithms
Opis:
By a result of McKenzie [4] finite directed graphs that satisfy certain connectivity and thinness conditions have the unique prime factorization property with respect to the cardinal product. We show that this property still holds under weaker connectivity and stronger thinness conditions. Furthermore, for such graphs the factorization can be determined in polynomial time.
Źródło:
Discussiones Mathematicae Graph Theory; 2007, 27, 3; 593-601
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control flow graphs and code coverage
Autorzy:
Gold, R.
Powiązania:
https://bibliotekanauki.pl/articles/908136.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
graf skierowany
graf przepływowy
testowanie oprogramowania
directed graph
control flow graph
graph reduction
software testing
statement coverage
branch coverage
Opis:
The control flow of programs can be represented by directed graphs. In this paper we provide a uniform and detailed formal basis for control flow graphs combining known definitions and results with new aspects. Two graph reductions are defined using only syntactical information about the graphs, but no semantical information about the represented programs. We prove some properties of reduced graphs and also about the paths in reduced graphs. Based on graphs, we define statement coverage and branch coverage such that coverage notions correspond to node coverage, and edge coverage, respectively.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2010, 20, 4; 739-749
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Domination hypergraphs of certain digraphs
Autorzy:
Sonntag, M.
Teichert, H. M.
Powiązania:
https://bibliotekanauki.pl/articles/254767.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
hypergraph
dominating set
directed graph
Opis:
If D = (V,A) is a digraph, its domination hypergraph DH(D) = (V, E) has the vertex set V and e ⊆ V is an edge of DH(D) if and only if e is a minimal dominating set of D. We investigate domination hypergraphs of special classes of digraphs, namely tournaments, paths and cycles. Finally, using a special decomposition/composition method we construct edge sets of domination hypergraphs of certain digraphs.
Źródło:
Opuscula Mathematica; 2010, 30, 2; 179-191
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Factoring directed graphs with respect to the cardinal product in polynomial time II
Autorzy:
Imrich, Wilfried
Klöckl, Werner
Powiązania:
https://bibliotekanauki.pl/articles/744038.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
directed graphs
cardinal product
graph algorithms
Opis:
By a result of McKenzie [7] all finite directed graphs that satisfy certain connectivity conditions have unique prime factorizations with respect to the cardinal product. McKenzie does not provide an algorithm, and even up to now no polynomial algorithm that factors all graphs satisfying McKenzie's conditions is known. Only partial results [1,3,5] have been published, all of which depend on certain thinness conditions of the graphs to be factored.
In this paper we weaken the thinness conditions and thus significantly extend the class of graphs for which the prime factorization can be found in polynomial time.
Źródło:
Discussiones Mathematicae Graph Theory; 2010, 30, 3; 461-474
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free probability induced by electric resistance networks on energy Hilbert spaces
Autorzy:
Cho, I.
Jorgensen, P. E. T.
Powiązania:
https://bibliotekanauki.pl/articles/254830.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
directed graphs
graph groupoids
electric resistance networks
ERN-groupoids
energy Hilbert spaces
ERN-algebras
free moments
free cumulants
Opis:
We show that a class of countable weighted graphs arising in the study of electric resistance networks (ERNs) are naturally associated with groupoids. Starting with a fixed ERN, it is known that there is a canonical energy form and a derived energy Hilbert space Hε. From Hε, one then studies resistance metrics and boundaries of the ERNs. But in earlier research, there does not appear to be a natural algebra of bounded operators acting on Hε. With the use of our ERN-groupoid, we show that Hε may be derived as a representation Hilbert space of a universal representation of a groupoid algebra [formula], and we display other representations. Among our applications, we identify a free structure of [formula] in terms of the energy form.
Źródło:
Opuscula Mathematica; 2011, 31, 4; 549-598
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pomiarowa sieć radiowa o niskim zużyciu energii
Energy efficient wireless sensor network
Autorzy:
Boniewicz, R.
Zieliński, M.
Powiązania:
https://bibliotekanauki.pl/articles/156068.pdf
Data publikacji:
2011
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
sieć radiowa
CC1100
moduł radiowy
Scilab
Metanet
graf skierowany
stanowisko pomiarowe
niskie zużycie energii
wireless sensor network
radio module
directed graph
measurement system
low energy consumption
Opis:
W artykule opisano prace badawcze służące zaprojektowaniu, symulacji i realizacji radiowej sieci pomiarowej charakteryzującej się niskim zużyciem energii. Proponowana sieć ma charakteryzować się równomiernym zużyciem energii przez wszystkie moduły oraz dynamicznym algorytmem trasowania pozwalającym na długotrwałą pracę sieci. W artykule opisano stanowisko służące do badań i kontroli sieci, metodę trasowania, a także sposób symulacji w środowisku Scilab. Podano także parametry charakteryzujące projektowaną sieć, takie jak czasy transmisji i pobór energii.
This paper presents research, design and simulations of an energy efficient wireless sensor network. It describes a routing protocol designed for evenly energy consumption. There is shown how to simulate a network in the Scilab environment. The test wireless sensor network including a measurement station and construction of radio modules are presented. The radio modules consists of Texas Instruments/chipcon's CC1100 transceiver and Atmel's ATmega32 microcontroller. The network can join up to 65535 radio modules (16 bit addressing). The measurement station consists of programmable power supply, an oscilloscope, precise multimeters and a JTAG module. It allows measuring the current consumption in different working modes, checking the time of operations and controlling the radio system. This solution will be used in a wireless water meter network. The most important feature in this application is a long working time (up to 10 years). The even energy consumption should extend the network reliability and its time of work.
Źródło:
Pomiary Automatyka Kontrola; 2011, R. 57, nr 12, 12; 1515-1517
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Review of Bayesian Networks and Structure Learning
Autorzy:
Koski, Timo J.T.
Noble, John
Powiązania:
https://bibliotekanauki.pl/articles/748766.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Bayesian networks, directed acyclic graph, Arthur Cayley, intervention calculus, graphical Markov model, Markov equivalence, structure learning
Opis:
Artykuł jest przegladem problemów analizowanych przy pomocy sieci bayesowskich. Siec bayesowska jest acyklicznym grafem skierowanym, w którym wezły oznaczaja zmienne, a krawedzie prawdopodobienstwa warunkowe czyli wpływy jednych zmiennych na inne. Autor przedstawia zaleznosc miedzy d-separowalnoscia a niezaleznoscia. Znaczna czesc pracy poswiecona jest dyskusji idei zawartych w pracy Arthura Cayley'a [8], która zawiera szereg pojec i pomysłów wykorzystywanych w teorii sieci bayesowskich takich jak faktoryzacja rozkładu, zaszumione bramki „LUB" oraz zastosowanie geometrii algebraicznej. Autor omawia równiez „calculus of intervention", pomysł pochodzacy od Pearla, gdy acykliczny graf skierowany (DAG) przedstawia przyczynowo-skutkowa strukture zaleznosci, oraz zwiazki pomiedzy pracami Cayley'a i Pearla.Wiekszosc zawartego w artykule materiału poswiecona jest rozpoznawaniu i wykrywaniu zaleznosci miedzy zmiennymi w oparciu o dwie główne metodologie: przeszukiwania i klasyfikacji oraz realizacji ograniczen. Algorytmy oparte na kontroli ograniczen czesto opieraja sie na załozeniu, ze dane do których algorytm jest stosowany pochodza z rozkładu spełniajacego załozenie wiernosci oznaczajacego równowaznosc d-separowalnosci i niezaleznosci. W pracy prezentowane sa rozwazania dla algorytmów opartych na realizacji ograniczen w  przypadkach gdy załozenie wiernosci nie jest spełnione. Przeprowadzono krótka dyskusje kontrowersji zwiazanych z wykrywaniem przypadkowych powiazan.
This article reviews the topic of Bayesian networks. A Bayesian network  is a factorisation of a probability distribution along a directed acyclic graph. The relation between graphical d-separation and independence is described. A short article by Arthur Cayley (1853) [7] is discussed, which laid ideas later used in Bayesian networks: factorisation, the noisy `or' gate, applications of algebraic geometry to Bayesian networks. The ideas behind Pearl's intervention calculus when the DAG represents a causal dependence structure; the relation between the work of Cayley and Pearl is commented on.Most of the discussion is about structure learning, outlining the two main approaches; search and score versus constraint based. Constraint based algorithms often rely on the assumption of faithfulness, that the data to which the algorithm is applied is generated from distributions satisfying a faithfulness assumption where graphical d- separation and independence are equivalent. The article presents some considerations for constraint based algorithms based on recent data analysis, indicating a variety of situations where the faithfulness assumption does not hold.
Źródło:
Mathematica Applicanda; 2012, 40, 1
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signed directed graph based modeling and its validation from process knowledge and process data
Autorzy:
Yang, F.
Shah, S. L.
Xiao, D.
Powiązania:
https://bibliotekanauki.pl/articles/331384.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
graf skierowany
diagnostyka uszkodzeń
system oceny zagrożeń
signed directed graph
transfer entropy
process topology
fault diagnosis
process hazard assessment
Opis:
This paper is concerned with the fusion of information from process data and process connectivity and its subsequent use in fault diagnosis and process hazard assessment. The Signed Directed Graph (SDG), as a graphical model for capturing process topology and connectivity to show the causal relationships between process variables by material and information paths, has been widely used in root cause and hazard propagation analysis. An SDG is usually built based on process knowledge as described by piping and instrumentation diagrams. This is a complex and experience-dependent task, and therefore the resulting SDG should be validated by process data before being used for analysis. This paper introduces two validation methods. One is based on cross-correlation analysis of process data with assumed time delays, while the other is based on transfer entropy, where the correlation coefficient between two variables or the information transfer from one variable to another can be computed to validate the corresponding paths in SDGs. In addition to this, the relationship captured by data-based methods should also be validated by process knowledge to confirm its causality. This knowledge can be realized by checking the reachability or the influence of one variable on another based on the corresponding SDG which is the basis of causality. A case study of an industrial process is presented to illustrate the application of the proposed methods.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 1; 41-53
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of constructing the frame of a directed graph
Autorzy:
Hofuku, I.
Oshima, K.
Powiązania:
https://bibliotekanauki.pl/articles/331224.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
directed graph
node clustering
Perron-Frobenius theorem
information retrieval
graf skierowany
węzeł grafu
twierdzenie Perrona-Frobeniusa
wyszukiwanie informacji
Opis:
In web search engines, such as Google, the ranking of a particular keyword is determined by mathematical tools, e.g., Pagerank or Hits. However, as the size of the network increases, it becomes increasingly difficult to use keyword ranking to quickly find the information required by an individual user. One reason for this phenomenon is the interference of superfluous information with the link structure. The World Wide Web can be expressed as an enormous directed graph. The purpose of the present study is to provide tools for studying the web as a directed graph in order to find clues to the solution of the problem of interference from superfluous information, and to reform the directed graph to clarify the relationships between the nodes.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 4; 823-837
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Domination of Cartesian Product of Directed Cycles: Results for Certain Equivalence Classes of Lengths
Autorzy:
Mollard, Michel
Powiązania:
https://bibliotekanauki.pl/articles/30146581.pdf
Data publikacji:
2013-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
directed graph
Cartesian product
domination number
directed cycle
Opis:
Let \( \gamma ( \overrightarrow{C_m} \square \overrightarrow{C_n} ) \) be the domination number of the Cartesian product of directed cycles \( \overrightarrow{C_m} \) and \( \overrightarrow{C_n} \) for $m, n \ge 2 $. Shaheen [13] and Liu et al. ([11], [12]) determined the value of \( \gamma ( \overrightarrow{C_m} \square \overrightarrow{C_n} ) \) when $ m \le 6 $ and [12] when both $m$ and $ n \equiv 0 (\mod 3) $. In this article we give, in general, the value of \( \gamma ( \overrightarrow{C_m} \square \overrightarrow{C_n} ) \) when $ m \equiv 2(\mod 3) $ and improve the known lower bounds for most of the remaining cases. We also disprove the conjectured formula for the case $ m \equiv 0 ( \mod 3) $ appearing in [12].
Źródło:
Discussiones Mathematicae Graph Theory; 2013, 33, 2; 387-394
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Visualisation of concurrent processes
Autorzy:
Mikulski, Ł
Piątkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/205775.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
concurrency
partial order
Hasse diagram
directed acyclic graph
linearisation
Mazurkiewicz traces
Opis:
Mazurkiewicz traces are a widely used model for describing the languages of concurrent systems computations. The causal structure of atomic actions occurring in a process modeled as a trace generates a partial order. Hasse diagrams of such order are very common structures used for presentation and investigation in the concurrency theory, especially from the behavioural perspective. We present effective algorithms for Hasse diagrams construction and transformation. Later on, we use them for enumeration of all linearisations of the partial order that represents a concurrent process. Additionally, we attach the flexible visual implementation of all considered Algorithms.
Źródło:
Control and Cybernetics; 2013, 42, 3; 699-725
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies