Changes in Earth’s environment are expected to stimulate changes in the composition and structure of ecosystems, but it is still unclear how the dynamics of these responses will play out over time. In long-lived forest systems, communities of established individuals may be resistant to respond to directional climate change, but may be highly sensitive to climate effects during the early life st...

The purpose of this study is to determine the woody species diversity in Sweet chestnut tree, Hazel-tree and Italian cypress ecosystems in the Guilan forests. A lozeng 0.5 ha sample plot was selectively established on each site. In the Sweet chestnut ecosystems , 4 sites were classified, whereas 10 sites of Hazel tree and Italian cypress ecosystems were classified based on species composition. ...

The expressive power of regularity-preserving multi bottomup tree transducers (mbot) is investigated. These mbot have very attractive theoretical and algorithmic properties. However, their expressive power is not well understood. It is proved that despite the restriction their power still exceeds that of composition chains of linear extended top-down tree transducers with regular look-ahead (xt...

We argüe that in order to exploit both Independent Andand Or-parallelism in Prolog programs there is advantage in recomputing some of the independent goals, as opposed to all their solutions being reused. We present an abstract model, called the CompositionTree, for representing and-or parallelism in Prolog Programs. The Composition-tree closely mirrors sequential Prolog execution by recomputin...

The composition, abundance, and relationship to trunk-surface characteristics of the tree-trunk surface arthropod fauna were studied from August, 1984 to January, 1985 in a beech-maple forest in southwestern Ohio. Samples of trunk-surface arthropods were taken monthly from American beech and sugar maple trees. Although resource levels on the two tree species did not differ significantly, arthro...

This paper presents an analysis of bound variable pronouns in English using Synchronous Tree Adjoining Grammar. Bound variables are represented as multi-component sets, composing in delayed tree-local derivations. We propose that the observed anti-locality restriction on English bound variables can be for-malised in terms of a constraint on the delay in the composition of the bound variable mul...

The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree transducers (macro tree-to-string transducers, respectively). For this purpose we define several pushdown...

In this paper we consider the closure UCI(Rel) of the class of relabeling tree transformations, under U=union, C=composition and I=iteration. We give a characterization of UCI(Rel) in terms of a short expression built up from Rel with composition and iteration. We also give a characterization of UCI(Rel) in terms of one-step rewrite relations of very simple term rewrite systems. We give a simil...

Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical topics like composition, decomposition, domains, and ranges of the induced translation classes. ...

Symbolic transducers are useful in the context of web security as they form the foundation for sanitization of potentially malicious data. We define Symbolic Tree Transducers as a generalization of Regular Transducers as finite state input-output tree automata with logical constraints over a parametric background theory. We examine key closure properties of Symbolic Tree Transducers and we deve...