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Wyniki wyszukiwania dla: tree
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TREE PHYSIOLOGY
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Tree-Ring Research
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Tree Genetics & Genomes
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The complexity of bicriteria tree-depth
PublikacjaThe tree-depth problem can be seen as finding an elimination tree of minimum height for a given input graph G. We introduce a bicriteria generalization in which additionally the width of the elimination tree needs to be bounded by some input integer b. We are interested in the case when G is the line graph of a tree, proving that the problem is NP-hard and obtaining a polynomial-time additive 2b-approximation algorithm. This particular...
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The reliability of tree and star networks
PublikacjaThis paper investigated the reliability of tree and star networks. Following measures of network reliability are assumed: the expected number of nodes, that can communicate with the central node; the expected number of node pairs, that are connected by a path through the central node; the expected number of node pairs communicating.
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The reliability of tree and star networks.
PublikacjaOne of the important parameters characterizing the quality of computer networks is the network's reliability with respect to failures of the communication links and nodes. This chapter investigated the reliability of tree and star networks. The tree and star topology is used in centralized computer networks. In centralized computer networks all communication must take place through some central computer. Following measures of network...
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Perfect hashing tree automata
PublikacjaWe present an algorithm that computes a function that assigns consecutive integers to trees recognized by a deterministic, acyclic, finite-state, bottom-up tree automaton. Such function is called minimal perfect hashing. It can be used to identify trees recognized by the automaton. Its value may be seen as an index in some other data structures. We also present an algorithm for inverted hashing.Przedstawiamy algorytm, który oblicza...
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A note on mixed tree coloring
PublikacjaZaproponowano liniowy algorytm dla problemu kolorowania mieszanego w drzewach, uzyskując tym samym poprawę w stosunku do algorytmu o złożoności O(n^2) podanego w pracy [P. Hansen, J. Kuplinsky, D. de Werra, Mixed graph colorings, Math. Methods Oper. Res. 45 (1997) 145-160].
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An implementation of deterministic tree automata minimization
PublikacjaWstępujący, deterministyczny, skończony automat drzewiasty (DTA) może być używany jako struktura danych do przechowywania zbiorów nieuporządkowanych drzew bez narzuconej liczby poddrzew. Takie automaty są zwykle rzadsze niż automaty działające na napisach i dlatego należy zwrócić szczególną uwagę na ich wydajną minimalizację. W dostępnej literaturze jest jednak ciężko znaleźć proste i szczegółowe opisy procedury minimalizacji....
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Lower bound on the domination number of a tree.
PublikacjaW pracy przedstawiono dolne ograniczenie na liczbę dominowania w drzewach oraz przedstawiono pełną charakterystykę grafów ekstremalnych.
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PLoS Currents-Tree of Life
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On extremal sizes of locally k-tree graphs
PublikacjaA graph G is a locally k-tree graph if for any vertex v the subgraph induced by the neighbours of v is a k-tree, k>=0, where 0-tree is an edgeless graph, 1-tree is a tree. We characterize the minimum-size locally k-trees with n vertices. The minimum-size connected locally k-trees are simply (k + 1)-trees. For k >= 1, we construct locally k-trees which are maximal with respect to the spanning subgraph relation. Consequently, the...
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Evaluation of the content of inorganic anions in tree saps
PublikacjaTree saps were once commonly used in the countries of Northern, Central and Eastern Europe. Although once almost forgotten, their popularity has been growing recently as part of an interest in organic food and traditional medicine. Tree saps, tapped mainly from birch and maple trees, are drunk both fresh and fermented or are used as raw material for the production of food products, e.g. syrups. The aim of this study was to determine...
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Incremental construction of Minimal Tree Automata [online]
PublikacjaWe describe an algorithm that allows the incremental addition or removal of unranked ordered trees to minimal frontier-to-root deterministic tree automaton (DTA). The algorithm takes a tree t and a minimal DTA A as input; it outputs a minimal DTA A' which accepts the language L(A) accepted by A incremented (or decremented) with the tree t. The algorithm can be used to efficiently maintain dictionaries which store large collections...
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Average Size of a Suffix Tree for Markov Sources
PublikacjaWe study a suffix tree built from a sequence generated by a Markovian source. Such sources are more realistic probabilistic models for text generation, data compression, molecular applications, and so forth. We prove that the average size of such a suffix tree is asymptotically equivalent to the average size of a trie built over n independentsequences from the same Markovian source. This equivalenceis only known for memoryless...
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Bounds on the vertex-edge domination number of a tree
PublikacjaA vertex-edge dominating set of a graph $G$ is a set $D$ of vertices of $G$ such that every edge of $G$ is incident with a vertex of $D$ or a vertex adjacent to a vertex of $D$. The vertex-edge domination number of a graph $G$, denoted by $\gamma_{ve}(T)$, is the minimum cardinality of a vertex-edge dominating set of $G$. We prove that for every tree $T$ of order $n \ge 3$ with $l$ leaves and $s$ support vertices we have $(n-l-s+3)/4...
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Lower bound on the paired domination number of a tree
PublikacjaW pracy przedstawione jest ograniczenie dolne dla liczby dominowania parami oraz scharakteryzowane są wszystkie drzewa ekstremalne.
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Tool support for ECSDM fault tree methodology
PublikacjaExtended Common Safety Description Model (ECSDM) jest językiem do formalnej specyfikacji systemów związanych z bezpieczeństwem oraz ich komponentów. Język ten zawiera konstrukcje umożliwiające specyfikację zależności czasowych. Może on zostać użyty w analizie drzew błędów, aby uzyskać jednoznaczną specyfikację hazardów w sytuacji, gdy są one uzależnione od związków czasowych pomiędzy przyczynami. Artykuł opisuje narzędzie wytworzone...
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Complexity of weak acceptonic conditions in tree automata
PublikacjaRozważano złożoność problemu pustości dla automatów na drzewach ze słabymi warunkami akceptowalności. Rozważano także translacje pomiędzy słabymi i silnymi warunkami akceptowalności.
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MINERAL CONTENT OF TREE SAP FROM THE SUBCARPATHIAN REGION
Publikacjabut also as medicinal substance in folk medicine. Traditionally, it was used to treat various conditions, mostly anaemia and chronic fatigue. This study has been designed to establish the content of metallic elements (sodium, potassium, calcium, magnesium, zinc and copper) in sap collected from eight different species (silver birch, downy birch, hornbeam, Norway maple, boxelder maple, black walnut, black alder and white willow)...
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Atmospheric deposition in coniferous and deciduous tree stands in Poland
PublikacjaThe objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric...
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Gossiping by energy-constrained mobile agents in tree networks
PublikacjaEvery node of an edge-weighted tree network contains a data packet. At some nodes are placed mobile agents, each one possessing an amount of energy (not necessarily the same for all agents). While walking along the network, the agents spend the energy proportionally to the distance traveled and collect copies of the data packets present at the visited network nodes. An agent visiting a node deposits there copies of all currently...
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Lower bound on the weakly connected domination number of a tree
PublikacjaPraca dotyczy dolnego ograniczenia liczby dominowania słabo spójnego w drzewach (ograniczenie ze względu na ilość wierzchołków i ilość wierzchołków końcowych w drzewie).
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Lower bound on the distance k-domination number of a tree
PublikacjaW artykule przedstawiono dolne ograniczenie na liczbę k-dominowania w drzewach oraz scharakteryzowano wszystkie grafy ekstremalne.
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An algorithm for listing all minimal double dominating sets of a tree
PublikacjaWe provide an algorithm for listing all minimal double dominating sets of a tree of order $n$ in time $\mathcal{O}(1.3248^n)$. This implies that every tree has at most $1.3248^n$ minimal double dominating sets. We also show that this bound is tight.
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An Alternative Proof of a Lower Bound on the 2-Domination Number of a Tree
PublikacjaA 2-dominating set of a graph G is a set D of vertices of G such that every vertex not in D has a at least two neighbors in D. The 2-domination number of a graph G, denoted by gamma_2(G), is the minimum cardinality of a 2-dominating set of G. Fink and Jacobson [n-domination in graphs, Graph theory with applications to algorithms and computer science, Wiley, New York, 1985, 283-300] established the following lower bound on the 2-domination...
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An upper bound on the total outer-independent domination number of a tree
PublikacjaA total outer-independent dominating set of a graph G=(V(G),E(G)) is a set D of vertices of G such that every vertex of G has a neighbor in D, and the set V(G)D is independent. The total outer-independent domination number of a graph G, denoted by gamma_t^{oi}(G), is the minimum cardinality of a total outer-independent dominating set of G. We prove that for every tree T of order n >= 4, with l leaves and s support vertices we have...
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An upper bound for the double outer-independent domination number of a tree
PublikacjaA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)\D is independent. The double outer-independent domination number of a graph G, denoted by γ_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We prove...
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A lower bound on the double outer-independent domination number of a tree
PublikacjaA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)D is independent. The double outer-independent domination number of a graph G, denoted by gamma_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We...
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An Algorithm for Listing All Minimal 2-Dominating Sets of a Tree
PublikacjaWe provide an algorithm for listing all minimal 2-dominating sets of a tree of order n in time O(1.3248n) . This implies that every tree has at most 1.3248 n minimal 2-dominating sets. We also show that this bound is tigh.
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A lower bound on the total outer-independent domination number of a tree
PublikacjaA total outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G has a neighbor in D, and the set V(G)D is independent. The total outer-independent domination number of a graph G, denoted by gamma_t^{oi}(G), is the minimum cardinality of a total outer-independent dominating set of G. We prove that for every nontrivial tree T of order n with l leaves we have gamma_t^{oi}(T) >= (2n-2l+2)/3,...
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An upper bound on the 2-outer-independent domination number of a tree
PublikacjaA 2-outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of V(G)D has a at least two neighbors in D, and the set V(G)D is independent. The 2-outer-independent domination number of a graph G, denoted by gamma_2^{oi}(G), is the minimum cardinality of a 2-outer-independent dominating set of G. We prove that for every nontrivial tree T of order n with l leaves we have gamma_2^{oi}(T) <= (n+l)/2,...
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Empirical analysis of tree-based classification models for customer churn prediction
PublikacjaCustomer churn is a vital and reoccurring problem facing most business industries, particularly the telecommunications industry. Considering the fierce competition among telecommunications firms and the high expenses of attracting and gaining new subscribers, keeping existing loyal subscribers becomes crucial. Early prediction of disgruntled subscribers can assist telecommunications firms in identifying the reasons for churn and...
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Perfect hashing with pseudo-minimal bottom-up deterministic tree automata
PublikacjaWe describe a technique that maps unranked trees to their hash codes using a bottom-up deterministic tree automaton (DTA). In contrast to techniques implemented with minimal tree automata, our procedure builds a pseudo-minimal DTA. Pseudo-minimal automata are larger than the minimal ones but in turn the mapping can be arbitrary, so it can be determined prior to the automaton construction. We also provide procedures to build incrementally...
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A city is not a tree: a multi-city study on street network and urban life
PublikacjaChristopher Alexander, a British-American scholar, differentiated an old (natural) city from a new (planned) one by structure. The former resembles a “semilattice”, or a complex system encompassing many interconnected sub-systems. The latter is shaped in a graph-theoretical “tree”, which lacks the structural complexity as its sub-systems are compartmentalized into a single hierarchy. This structural distinction explains why, or...
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Critical Case Stochastic Phylogenetic Tree Model via the Laplace Transform
PublikacjaBirth–and–death models are now a common mathematical tool to describe branching patterns observed in real–world phylogenetic trees. Liggett and Schinazi (2009) is one such example. The authors propose a simple birth–and–death model that is compatible with phylogenetic trees of both influenza and HIV, depending on the birth rate parameter. An interesting special case of this model is the critical case where the birth rate equals the...
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A self-stabilizing algorithm for finding a spanning tree in a polynomial number of moves
PublikacjaW pracy rozważa się rozproszony model obliczeń, w którym struktura systemu jest reprezentowana przez graf bezpośrednich połączeń komunikacyjnych. W tym modelu podajemy nowy samostabilizujący algorytm znajdowania drzewa spinającego. Zgodnie z naszą wiedzą jest to pierwszy algorytm dla tego problemu z gwarantowaną wielomianową liczbą ruchów.
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Minimum vertex ranking spanning tree problem for chordal and proper interval graphs
PublikacjaW pracy rozważamy problem szukania, dla danego grafu prostego, drzewa spinającego, którego uporządkowana liczba chromatyczna jest minimalna. K.~Miyata i inni dowiedli w [Np-hardness proof and an approximation algorithm for the minimum vertex ranking spanning tree problem,Discrete Appl. Math. 154 (2006) 2402-2410], że odpowiedni problem decyzyjny jest NP-trudny już w przypadku pytania o istnienie uporządkowanego 4-pokolorowania....
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Fault Tree Analysis and Failure Diagnosis of Marine Diesel Engine Turbocharger System
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Tree-based homogeneous ensemble model with feature selection for diabetic retinopathy prediction
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Construction of a picewise-linear classifier by applaing discriminant analysis to decision tree induction
PublikacjaArtykuł prezentuje metodę konstrukcji drzew decyzyjnych. W odróżnieniu od większości popularnych algorytmów, które wybierają pojedyncze cechy do budowy reguł decyzyjnych w węzłach drzewa, ta metoda łączy wszystkie cechy. Używa ona wieloklasowego kryterium Fishera do wydzielenia nowych cech, które są liniowa kombinacją cech pierwotnych. Takie drzewa mogą aproksymować złożone regiony decyzyjne używając mniejszej liczby węzłów w porównaniu...
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Multidimensional Feature Selection and Interaction Mining with Decision Tree Based Ensemble Methods
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INDIVIDUAL TREE DETECTION FROM UAV LIDAR DATA IN A MIXED SPECIES WOODLAND
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Electrical Tree Growth Behavior Under AC and DC High Voltage in Power Cables
PublikacjaThis work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC...
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The partial-order tree: a new structure for indexing on complex attributes in object-oriented databases
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Adaptive neuro fuzzy and fuzzy decision tree classifiers as applied to sea floor characterization.
PublikacjaPrzedstawiono wyniki badań wpływu różnych parametrów echa odbitego od dna morskiego na dokładność klasyfikacji typu dna przy pomocy sieci neuronowej z logiką rozmytą i przy pomocy drzew decyzyjnych. W szczególności uwzględniono takie parametry echa jak: energia, amplituda i nachylenie opadającego zbocza, wzbogacone o współczynniki falkowe otrzymane z dyskretnej transformacji falkowej (DWT).
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The energy consumption during the birch tree sap concentration process using the reverse osmosis system
PublikacjaBirch tree sap was concentrated by mens of the reversed osmosis technique. The energy consumption in a small-scale pilot apparatus was estimated. The threshold value for the water removal above which the specific energy consumption significantly increased was identified. Below the threshold value the reversed osmosis had low energy demand and could be an attractive method for the production of birch tree sap-based beverages.
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Tree rings as an indicator of atmospheric pollutant deposition to subalpine spruce forests in the Sudetes (Southern Poland)
PublikacjaIn spite of their moderate altitude (1000–1600m a.s.l.), the Western SudetyMountains belong to areas with the most efficient fog precipitation in Europe. Intense industrial activity in the area of windward western foothills caused an exceptional intensification of atmospheric pollutant deposition via precipitation and fog to take place since the 1950s. In the second half of the 1970s a massive spruce forest dieback began affecting...
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Family Tree for Aqueous Organic Redox Couples for Redox Flow Battery Electrolytes: A Conceptual Review
PublikacjaRedox flow batteries (RFBs) are an increasingly attractive option for renewable energy storage, thus providing flexibility for the supply of electrical energy. In recent years, research in this type of battery storage has been shifted from metal-ion based electrolytes to soluble organic redox-active compounds. Aqueous-based organic electrolytes are considered as more promising electrolytes to achieve “green”, safe, and low-cost...
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A Fuzzy Event Tree Model for Accident Scenario Analysis of Ship Stuck in Ice in Arctic Waters
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