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Search results for: trees
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Forests Trees and Livelihoods
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Trees Forests and People
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TREES-STRUCTURE AND FUNCTION
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Preserving Trees in Automata
PublicationWe present a method to store additional information in a minimal automaton so that it is possible to compute a corresponding tree node number for a state. The number can then be used to retrieve additional information. The method works for minimal (and any other) deterministic acyclic finite state automata (DFAs). We also show how to compute the inverse mapping.
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On the partition dimension of trees
PublicationGiven an ordered partition Π={P1,P2,…,Pt} of the vertex set V of a connected graph G=(V,E), the partition representation of a vertex v∈V with respect to the partition Π is the vector r(v|Π)=(d(v,P1),d(v,P2),…,d(v,Pt)), where d(v,Pi) represents the distance between the vertex vv and the set Pi. A partition Π of V is a resolving partition of G if different vertices of G have different partition representations, i.e., for every...
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Paired bondage in trees
PublicationW pracy zdefiniowano pojęcie liczby zniewolenia parami jako moc najmniejszego zbioru krawędzi, którego usunięcie z grafu spowoduje wzrost liczby dominowania parami. W szczególności scharakteryzowane są wszystkie drzewa, w których liczba zniewolenia wynosi 0, czyli takie, w których usunięcie dowolnego podzbioru krawędzi nie zwiększy liczby dominowania parami.
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Total chromatic sum for trees
PublicationThe total chromatic sum of a graph is the minimum sum of colors (natural numbers) taken over all proper colorings of vertices and edges of a graph. We provide infinite families of trees for which the minimum number of colors to achieve the total chromatic sum is equal to the total chromatic number. We construct infinite families of trees for which these numbers are not equal, disproving the conjecture from 2012.
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Connected searching of weighted trees
PublicationW pracy pokazano, że problem spójnego przeszukiwania drzew ważonych jest silnie NP-zupełny. Problem pozostaje trudnym dla drzew z jednym wierzchołkiem o stopniu większym niż 2. Ponadto, przedstawiony został wielomianowy optymalny algorytm dla klasy drzew z ograniczonym stopniem.
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Connected searching of weighted trees
PublicationW artykule rozważamy problem spójnego przeszukiwania drzew obciążonych. Autorzy w [L. Barriere i inni, Capture of an intruder by mobile agents, SPAA'02 (2002) 200-209] twierdzą, że istnieje wielomianowy algorytm dla problemu obliczania optymalnej strategii przeszukiwania obciążonego drzewa. W niniejszej pracy pokazano, że problem ten jest obliczeniowo trudny nawet dla wierzchołkowo-obciążonych drzew (wagi krawędzi równe 1) oraz...
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The complexity of list ranking of trees
PublicationUporządkowane kolorowanie grafu polega na takim etykietowaniu jego wierzchołków, aby każda ścieżka łącząca dwa wierzchołki o tym samym kolorze zawierała wierzchołek o kolorze wyższym. Jeśli każdy wierzchołek posiada dodatkowo listę dozwolonych dla niego etykiet, to mówimy wówczas o uporządkowanym listowym kolorowaniu wierzchołków. W pracy wskazano szereg klas grafów, dla których problem jest trudny: pełne drzewa binarne, drzewa...
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Construction of phylogenetic trees with topological constraints
PublicationThis paper proposes a method of reconstruction of phylogenetic trees based on heuristic search with topological constraints. Using topological constraints it is possible to reduce the set of solutions as well as to enforce that the result is consistent with a given hypothesis about the evolution process within some group of species. Along with this work a number of algorithms used for phylogenetic analysis were implemented. Those...
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Properties of the triset metric for phylogenetic trees
Publicationthe following paper presents a new polynomial time metric for unrootedphylogenetic trees (based on weighted bipartite graphs and the method ofdetermining a minimum perfect matching) and its properties. also many its properties are presented.
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Total restrained domination numbers of trees
PublicationOpisane są wszystkie drzewa, w których liczby dominowania totalnego i totalno - powściągniętego są sobie równe, a także podano dolne ograniczenie na liczbę dominowania totalno - powściągniętego w drzewach.
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Total outer-connected domination in trees
PublicationW pracy przedstawiono dolne ograniczenie na liczbę dominowania totalnego zewnętrznie spójnego w grafach oraz scharakteryzowano wszystkie drzewa osiągające to ograniczenie.
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Minimal 2-dominating sets in Trees
PublicationWe provide an algorithm for listing all minimal 2-dominating sets of a tree of order n in time O(1.3247^n). This leads to that every tree has at most 1.3247^n minimal 2-dominating sets. We also show that thisbound is tight.
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TreeCmp: Comparison of Trees in Polynomial Time
PublicationMetryki filogenetyczne umożliwiają ocenę jakości wyników analizy filogenetycznej oraz wiarygodności algorytmów przeprowadzających taką analizę. Aplikacja TreeCmp oferuje efektywne, wielomianowe implementacje ośmiu takich metryk (dla drzew nieukorzenionych i zawierających korzeń) zdefiniowanych dla dowolnych filogenez (nie koniecznie binarnych). Program ten jako pierwszy umożliwia wyznaczanie nowych metryk, definiowanych w oparciu...
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Approximate search strategies for weighted trees
PublicationW pracy podajemy 3-przybliżony algorytm dla problemu spójnego przeszukiwania drzew ważonych.
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Minimal double dominating sets in trees
PublicationWe 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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Reconfiguring Minimum Dominating Sets in Trees
PublicationWe provide tight bounds on the diameter of γ-graphs, which are reconfiguration graphs of the minimum dominating sets of a graph G. In particular, we prove that for any tree T of order n ≥ 3, the diameter of its γ-graph is at most n/2 in the single vertex replacement adjacency model, whereas in the slide adjacency model, it is at most 2(n − 1)/3. Our proof is constructive, leading to a simple linear-time algorithm for determining...
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Isolation Number versus Domination Number of Trees
PublicationIf G=(VG,EG) is a graph of order n, we call S⊆VG an isolating set if the graph induced by VG−NG[S] contains no edges. The minimum cardinality of an isolating set of G is called the isolation number of G, and it is denoted by ι(G). It is known that ι(G)≤n3 and the bound is sharp. A subset S⊆VG is called dominating in G if NG[S]=VG. The minimum cardinality of a dominating set of G is the domination number, and it is denoted by γ(G)....
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On a matching distance between rooted phylogenetic trees
PublicationThe Robinson–Foulds (RF) distance is the most popular method of evaluating the dissimilarity between phylogenetic trees. In this paper, we define and explore in detail properties of the Matching Cluster (MC) distance, which can be regarded as a refinement of the RF metric for rooted trees. Similarly to RF, MC operates on clusters of compared trees, but the distance evaluation is more complex. Using the graph theoretic approach...
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Polynomial triset metric for unrooted phylogenetic trees
Publicationthe following paper presents a polynomial triset metric for unrooted phylogenetic trees (based on weighted bipartite graphs and the method of determining a minimum edge cover) and its basic characteristics. also a list of further directions of research and examples of the wider use of this metric is presented.
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Trees having many minimal dominating sets
PublicationWe provide an algorithm for listing all minimal dominating sets of a tree of order n in time O(1.4656^n). This leads to that every tree has at most 1.4656^n minimal dominating sets. We also give an infinite family of trees of odd and even order for which the number of minimal dominating sets exceeds 1.4167^n, thus exceeding 2^{n/2}. This establishes a lower bound on the running time of an algorithm for listing all minimal dominating...
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Analyzing sets of phylogenetic trees using metrics
PublicationThe reconstruction of evolutionary trees is one of the primary objectives in phylogenetics. Such a tree represents historical evolutionary relationships between different species or organisms. Tree comparisons are used for multiple purposes, from unveiling the history of species to deciphering evolutionary associations among organisms and geographical areas. In this paper, we describe a general method for comparing phylogenetictrees...
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Total outer-connected domination numbers of trees
PublicationNiech G=(V,E) będzie grafem bez wierzchołków izolowanych. Zbiór wierzchołków D nazywamy zbiorem dominującym totalnym zewnętrznie spójnym jeżli każdy wierzchołek grafu ma sąsiada w D oraz podgraf indukowany przez V-D jest grafem spójnym. Moc najmniejszego zbioru D o takich własnościach nazywamy liczbą dominowania totalnego zewnątrznie spójnego. Praca m.in. zawiera dolne ograniczenie na liczbę dominowania totalnego zewnętrznie spójnego...
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Weakly connected domination stable trees [online]
PublicationPraca dotyczy pełnej charakteryzacji drzew stabilnych ze względu na liczbę dominowania słabo spójnego.
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The effect of trees in the road crown on road safety
PublicationW referacie przedstawiono problem występowania wypadków związanych z najechaniem na drzewo. Problem ten występuje w Polsce głównie w województwach północnych i zachodnich, co jest związane ze specyficznymi cechami sieci drogowej tego obszaru. Referat przedstawia negatywny wpływ drzew rosnących w koronie drogi na bezpieczeństwo ruchu drogowego oraz określa metody zapobiegania wypadkom związanym z najechaniem na drzewo. Ze względu...
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Modeling of event trees for the rapid scenario development
PublicationThe paper concerns the safety of ships in abnormal/damage conditions. Some conclusions following from the research associated with development of a method for safety assessment of ships in abnormal/damage conditions is presented in the paper. The method called SSAMADC (Ship Safety Assessment Method in Abnormal/Damage Conditions) is a risk-based method and is connected with application of the quantitative risk assessment QRA approach....
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Lossless Compression of Binary Trees with Correlated Vertex Names
PublicationCompression schemes for advanced data structures have become the challenge of today. Information theory has traditionally dealt with conventional data such as text, image, or video. In contrast, most data available today is multitype and context-dependent. To meet this challenge, we have recently initiated a systematic study of advanced data structures such as unlabeled graphs [1]. In this paper, we continue this program by considering...
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Tight bounds on global edge and complete alliances in trees
PublicationIn the talk the authors present some tight upper bounds on global edge alliance number and global complete alliance number of trees. Moreover, we present our NP-completeness results from [8] for global edge alliances and global complete alliances on subcubic bipartite graphs without pendant vertices. We discuss also polynomial time exact algorithms for finding the minimum global edge alliance on trees [7] and complete alliance...
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Why are trees still such a major hazard to drivers in Poland?
PublicationRoadside trees are one of Poland's most serious road safety issues. Since 2009 more than 2800 people have been killed as a result of tree collisions; this represents about 15% of all of Poland's accident fatalities between 2009 and 2013. In some of the country's regions striking a tree caused more than 30% of all road accident fatalities. With no proper regulations, guidelines or examples of good practice, roadside environments...
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Visual TreeCmp : Comprehensive Comparison of Phylogenetic Trees on the Web
Publication1. We present Visual TreeCmp—a package of applications for comparing phylogenetic tree sets. 2. Visual TreeCmp includes a graphical web interface allowing the visualization of compared trees and command line application extended by comparison methods recently proposed in the literature. 3. The phylogenetic tree similarity analysis in Visual TreeCmp can be performed using eighteen metrics, of which 11 are dedicated to rooted trees...
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Time versus space trade-offs for randezvous in trees
PublicationTwo identical (anonymous) mobile agents start from arbitrary nodes of an unknown tree and have to meet at some node. Agents move in synchronous rounds: in each round an agent can either stay at the current node or move to one of its neighbors. We consider deterministic algorithms for this rendezvous task. The main result of this paper is a tight trade-off between the optimal time of completing rendezvous and the size of memory...
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On trees attaining an upper bound on the total domination number
PublicationA total 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. The total domination number of a graph G, denoted by γ_t(G), is the minimum cardinality of a total dominating set of G. Chellali and Haynes [Total and paired-domination numbers of a tree, AKCE International Journal of Graphs and Combinatorics 1 (2004), 69-75] established the following upper bound on the total domination...
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Collaborative Exploration of Trees by Energy-Constrained Mobile Robots
PublicationWe study the problem of exploration of a tree by mobile agents (robots) that have limited energy. The energy constraint bounds the number of edges that can be traversed by a single agent. We use a team of agents to collectively explore the tree and the objective is to minimize the size of this team. The agents start at a single node, the designated root of the tree and the height of the tree is assumed to be less than the energy...
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Edge-chromatic sum of trees and bounded cyclicity graphs
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Matching Split Distance for Unrooted Binary Phylogenetic Trees
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A linear time algorithm for edge coloring of binomial trees
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Matching Split Distance for Unrooted Binary Phylogenetic Trees
PublicationRekonstrukcja drzew ewolucji jest jednym z głównych celów w bioinformatyce. Drzewa filogenetyczne reprezentuje historię ewolucji i związki pokrewieństwa między różnymi gatunkami. W pracy proponujemy nową ogólną metodę określania odległości między nieukorzenionymi drzewami filogenetycznymi, szczególnie użyteczną dla dużych zbiorów gatunków. Następnie podajemy szczegółowe własności jednej metryki określonej przy użyciu tej metody...
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Approximation Strategies for Generalized Binary Search in Weighted Trees
PublicationWe consider the following generalization of the binary search problem. A search strategy is required to locate an unknown target node t in a given tree T. Upon querying a node v of the tree, the strategy receives as a reply an indication of the connected component of T\{v} containing the target t. The cost of querying each node is given by a known non-negative weight function, and the considered objective is to minimize the total...
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Comparing phylogenetic trees using a minimum weight perfect matching
PublicationA phylogenetic tree represents historical evolutionary relationshipbetween different species or organisms. There are various methods for reconstructing phylogenetic trees.Applying those techniques usually results in different treesfor the same input data. An important problem is to determinehow distant two trees reconstructed in such a wayare from each other. Comparing phylogenetic trees is alsouseful in mining phylogenetic information...
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Ranking ecosystem services delivered by trees in urban and rural areas
PublicationPolicies and strategies for tree management and protection on a national, regional, and local level have not sufficiently considered differences between rural and urban areas. We used expert knowledge to compare rural and urban areas in a case study evaluating the relative importance of ecosystem services (ES) in policy development. The Analytic Hierarchy Process (AHP) and focus group discussions were used to rank 17 ES, representing...
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A proposition for integrating elements of game universe by means of behavioral trees
PublicationModern computer games often involve autonomous beings collaborating and competing with each other to reach their objectives in the game universe. It seems only natural to use agent-oriented approach in such cases. This article identifies the rules of building a game universe as an environment for executing agents. The paper also covers a method for decomposing compound behaviors into behavioral trees. Dividing complex behaviors...
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On trees with equal domination and total outer-independent domination numbers
PublicationFor a graph G=(V,E), a subset D subseteq V(G) is a dominating set if every vertex of V(G)D has a neighbor in D, while it is a total outer-independent dominating set if every vertex of G has a neighbor in D, and the set V(G)D is independent. The domination (total outer-independent domination, respectively) number of G is the minimum cardinality of a dominating (total outer-independent dominating, respectively) set of G. We characterize...
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Enumerations of Plane Trees with Multiple Edges and Raney Lattice Paths
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Ranking ecosystem services delivered by trees in urban and rural areas
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Ensemble-Based Logistic Model Trees for Website Phishing Detection
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Trees with equal restrained domination and total restrained domination numbers
PublicationW publikacji scharakteryzowano wszystkie drzewa, w których liczby dominowania powściągniętego oraz podwójnie totalnego są sobie równe.
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Influence of an Interview Location on Opinions about the Ecosystem Services Provided by Trees
PublicationCollecting opinions regarding environmental management is essential, particularly in urban areas where space is limited, and interests often collide. However, the impact of the conditions in which the research is conducted on opinions and preferences elicited via surveys and interviews about the environment is usually taken for granted. The recent development of computer-aided survey methods allows a simulation of an environment,...
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Adjusting Game Difficulty by Recreating Behavioral Trees of Human Player Actions
PublicationThis paper presents a proposition of a method for adjusting game difficulty to the current level of player's skills in one-on-one games. The method is based on recognition of human player's actions and recording of those actions in the form of behavioral trees. Such trees are later used to drive behaviors of computer-controlled opponents so that human player has beat hit own strategy and improve on it, to win subsequent games....