for assessment and comparison of measuring density methods of festuca ovina, bromus tomentellus and prangos ferulacea, three plants communities are selected. in all of plant community, reference area was defined and samples 7000 (70*100) square meter was selected. whole the area, sampling was accumplished as systematic-random. in each area, 5 transect 100 meter are established. then in areas 70...

Let B be a square region in the plane. We give an efficient algorithm that takes a set P of n points from B, and produces a set M ⊂ B with the property that the distance to the second nearest point in M approximates the distance to the kth nearest point of P . That is, there are constants α, β ∈ R such that for all x ∈ B, we have αdP,k(x) ≤ dM,2(x) ≤ βdP,k(x), where dM,2 and dP,k denote the sec...

Most existing inductive learning algorithms assume the availability of a training set of labeled examples. In many domains, however, labeling the examples is a costly process that requires either intensive computation or manual labor. In such cases, it may be beneecial for the learner to be active by intelligent selection of examples for labeling with the goal of reducing the labeling cost. In ...

In the passive, traditional, approach to learning, the information available to the learner is a set of classiied examples, which are randomly drawn from the instance space. In many applications, however, the initial clas-siication of the training set is a costly process, and an intelligently selection of training examples from unla-beled data is done by an active learner. This paper proposes a...

In this work, one and two-dimensional lattices are studied theoretically by a statistical mechanical approach. The nearest and next-nearest neighbor interactions are both taken into account, and the approximate thermodynamic properties of the lattices are calculated. The results of our calculations show that: (1) even though the next-nearest neighbor interaction may have an insignificant ef...

primary information about different methods of vegetation sampling is important to researchers to decide about their sampling. in this study we applied five distance methods (closest individual, nearest neighbor, random pairs, point-centered quarter and angle orderd) to estimate plant density in three vegetation types including artemisia sieberi, juncus littoralis and punica granatum in mazanda...

A powerful existing technique for evaluating statistical mechanical quantities in two-dimensional Ising models is based on constructing a matrix representing the nearest-neighbor spin couplings and then evaluating the Pfaffian of the matrix. Utilizing this technique and other more recent developments in evaluating elements of inverse matrices and exact sampling, a method and computer code for s...