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Showing papers on "Tree (data structure) published in 1976"


Journal ArticleDOI

217 citations


Journal ArticleDOI
TL;DR: In this article, the effect of slope and aspect on the growth of white pine trees has been investigated using a regression model with the assumption of a maximum in the northeast quadrant (45 ø azimuth) and a minimum in the southwest quadrant.
Abstract: An expression for describing the effect of aspect and slope on tree growth is illustrated by the relation of western white pine site index to aspect, slope, and habitat type. Forest Sci. 22: 457-460. Additional key words. Site, Pinus monticola, western white pine. STUDIES of the effect of environmental factors on the growth of trees generally assume that the effect of aspect can be coded as a cosine function with the minimum shifted to the southwest quadrant and the maximum to the northeast quadrant. This assumption, first proposed by Gaiser (1951) with respect to site index, has been found to be an acceptable approximation in numerous later site index studies. However, for other measures of tree growth such as periodic diameter increment, the optimum aspect can be quite different. Indeed, in regression models, the aspect variable may have different effects depending on the choice of other factors to be included in the model. Beers and others (1966) have shown how the phase of the cosine function can be shifted to place the optimum at an arbitrary aspect. Searching techniques to locate the optimum for a given set of data as used by Hartung and Lloyd (1969) can be quite inefficient and depend for their success on a good initial guess of the location. Finally, the use of higher order sine or cosine functions to represent asymmetries was introduced by Carmean (1967). The purpose of this note is to show how the foregoing developments can be combined into a single technique whereby the a priori assumption of a maximum in the northeast quadrant (45 ø azimuth) and a minimum in the southwest quadrant can be replaced by an empirically determined location of the optimum without repeated calculations of the regression fit. In addition, it is argued that expressions for the effect of aspect should always be considered as terms involving an interaction with slope. The simple symmetrmal cosine curve assumption can also be modified to accommodate more asymmetrical forms of the response to aspect. The effect of aspect proposed by Beers and others is stated mathematically as B cosine (a-O) where B is the amplitude, a is the azimuth measured clockwise from north, and 0 is the phase shift that generally has been assumed to be 45 ø (Trimble and Weitzman 1956). Suppose now that instead of assuming the optimum aspect a priori we wish to estimate the phase shift angle from the data at hand. This can be accomplished quite readily by introducing both the cosine of a and the sine of a as two independent variables in the multiple regression for predicting the response to aspect (e.g., equation (1) in Figure 1). The regression coefficients estimated by least squares for these two independent variables can then be used to determine the phase shift (0) and the amplitude (B) from the relations given in Figure 1. The expressions for 0 in degrees depend on the signs of b• and b2 and the arc tan of the absolute value of the ratio: [ b2/b•l. These quations are commonly found among the \"formulae for reference\" in appendices to many mathematical texts, but their application to growth analyses apparently is not widely recognized. The simple variables, sine and cosine of azimuth, would suffice in the regression if all data were obtained from plots having about the same slope. However, plots on level ground supply no information on the effect of aspect on tree growth. Furthermore, it is reasonable to assume that the effect of aspect will increase on an adverse aspect up to the angle of slope that is perpendicular to the sun's rays. For greater slopes, the slight advantage of a decrease in incoming radiation is likely to be offset by decreasing soil depth. For these reasons, I recommend that the variables to represent the combined effect of slope and aspect be defined as the tangent of slope (slope percent) times the sine and cosine, respectively, of the azimuth. In this way, plots on flat ground will have a zero value for these two variables, but plots on steep ground will have high weights for the sine and cosine of aspect. In addition, the tangent of slope Principal Mensurationist, USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, Utah 84401, stationed in Moscow, Idaho, at the Forestry Sciences Laboratory, maintained in cooperation with the University of Idaho. Manuscript received April 15, 1976. volume 22, number 4, 1976 / 457 This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. should also be included as a separate independent variable to overcome the symmetry of the sine and cosine functions. Otherwise, the steeper slopes on favorable aspects would be predicted to be more favorable than the flatter slopes. The additive variable for slope percent permits the model to describe adverse or negligible slope effects on the more favorable aspects and increasingly severe conditions with •ncreasing slopes on the more unfavorable aspects. Example of the application of this technique •s taken from the study of the effect of environmental factors on the site index (S.I.) of western white pine (Pinus monticola Dougl.). The regression of site index on the factors of aspect, slope, and habitat type (Daubenmire and Daubenmire 1968) was calculated to be: ln(S.l.): 0.08070s cos(a) + 0.08423s sin(a) 0.12634s + hab

187 citations



Journal ArticleDOI
TL;DR: A syntactic approach and, in particular, a tree system may be used to represent and classify fingerprint patterns and a grammatical inference system is developed for the inference of complex structures.
Abstract: The purpose of this paper is to demonstrate how a syntactic approach and, in particular, a tree system may be used to represent and classify fingerprint patterns. The fingerprint impressions are subdivided into sampling squares which are preprocessed and postprocessed for feature extraction. A set of regular tree languages is used to describe the fingerprint patterns and a set of tree automata is used to recognize the coded patterns. In order to infer the structural configuration of the encoded fingerprints, a grammatical inference system is developed. This system utilizes a simple procedure to infer the numerous substructures and relies on a reachability matrix and a man-machine interactive technique for the inference of complex structures. The 92 fingerprint impressions were used to test the proposed approach. A set of 193 tree grammars was inferred from each sampling square of the 4 × 4 sampling matrix which is capable of generating about 2 × 1034 classes for the fingerprint patterns.

150 citations






Journal ArticleDOI
TL;DR: The new approach described in this paper uses dynamic programming to synthesize an optimal decision tree from which a program can be created, permitting generation of optimal programs for decision tables with as many as ten to twelve conditions.
Abstract: Previous approaches to the problem of automatically converting decision tables to computer programs have been based on decomposition At any stage, one condition is selected for testing, and two smaller problems (decision tables with one less condition) are created An optimal program (with respect to average execution time or storage space, for example) is located only through implicit enumeration of all possible decision trees using a technique such as branch-and-bound The new approach described in this paper uses dynamic programming to synthesize an optimal decision tree from which a program can be created Using this approach, the efficiency of creating an optimal program is increased substantially, permitting generation of optimal programs for decision tables with as many as ten to twelve conditions

63 citations


Journal ArticleDOI
TL;DR: It is suggested that batching be reconsidered for disk based online data retrieval systems since the potential reduction in processor demand may actually reduce response time.
Abstract: The technique of batching searches has been ignored in the context of disk based online data retrieval systems. This paper suggests that batching be reconsidered for such systems since the potential reduction in processor demand may actually reduce response time. An analysis with sample numerical results and algorithms is presented.

62 citations


Journal ArticleDOI
TL;DR: Taxonomic tree models of folk classification are implicitly generative because they produce appropriate statements which are not in the description itself, and routine classification behavior is a matter of selecting a characteristic of an organism relevant for action.
Abstract: Several arguments are made in this paper: (1) Taxonomic tree models of folk classification are implicitly generative because they produce appropriate statements which are not in the description itself. (2) The generative devices sometimes postulated—namely, transitive reasoning operating on chains of directly included taxa—do not account for some evidence which another model, the direct comparison between prototypic images, does. (3) Taxonomic trees are probably not stored directly in the memory except perhaps as “dwarf” trees consisting of contrast sets and their names. (4) Routine classification behavior is not so much a matter of producing giant taxonomic trees as it is a matter of selecting, in particular socioeconomic situations, a characteristic of an organism relevant for action.

Journal Article
Golumbic1
TL;DR: In this paper, three algorithms are given to construct a weighted r-ary tree with a given set of integer weighted leaves in which the weight of a parent node is 1 + max of its sons.
Abstract: Three algorithms are given to construct a weighted r-ary tree with a given set of integer weighted leaves in which the weight of a parent node is 1 + max of its sons. Two goals are of interest; to minimize 1) the weight of the root of the tree, and 2) the number of internal nodes.



Journal ArticleDOI
TL;DR: In this paper, a theoretical study of water tree mechanism is described and the growth of water trees is explained in respect of the effect of frequency, temperature and electric field strength, which corresponds well with the results of experiments made by many researchers.
Abstract: A theoretical study of water tree mechanism is described. Microscopic analyses (1),(2) of water trees revealed that they are composed of many water-filled micro-voids which are less than several microns in diameter. The mechanism of the void generation is explained by the thermo-dynamics in which the electric field is considered. Based on this mechanism, the growth of water tree is explained in respect of the effect of frequency, temperature and electric field strength. This corresponds well with the results of experiments made by many researchers. Also given are the characteristics of the start points of the tree and cable containing water tree.


Journal ArticleDOI
David Penny1
TL;DR: The process of determining the optimal phylogenetic tree from amino acid sequences or comparable data is divided into six stages and the importance is emphasised of stating a model and examining its predictions before a criterion is chosen to select the best network.
Abstract: The process of determining the optimal phylogenetic tree from amino acid sequences or comparable data is divided into six stages. Particular attention is given both to the criteria that are used when testing for the optimal tree and the problem of determining the position of the original ancestor. Four types of criteria for evaluating the optimal tree are considered: 1. parsimony (fewest total changes), 2. path lengths from an ancestor to existing species, 3. subtracting the difference between each pair of species as measured on the tree and as compared directly with the data (−excess differences−), 4. Moore Residual Coefficient.

Book
01 Jan 1976


MonographDOI
08 Sep 1976
TL;DR: Heidmann et al. as discussed by the authors present a literature review of causes and possible control of tree seedlings' frost heaving, which appears to be a surface soil phenomenon, and occurs because of a segregation of soil water which freezes into layers or lenses of ice.
Abstract: Heidmann, L. J. 1976. Frost heaving of tree seedlings: A literature review of causes and possible control. USDA For. Serv. Gen. Tech. Rep. RM-21, 10 p. Rocky Mt. For. and Range Exp. Stn., Fort Collins, Colo. Frost heaving of tree seedlings is more serious among seedlings less than 1 year old than among transplanted stock. It appears to be a surface soil phenomenon, and occurs because of a segregation of soil water which freezes into layers or lenses of ice. Lens formation causes an uplift of the surface soil and the tree seedling. Upon thawing, the tree remains in an extruded position on the soil surface while the soil recedes to approximately its original level. Segregation of the soil water occurs within the total matrix because of supercooling of the water in smaller soil pores and the water adsorbed on soil particles. The difference in freezing points provides the energy necessary to draw water to the ice lens and to lift the surface. Segregation of soil water is related to soil permeability and negative pressure on the water. A silty soil is more likely to heave because the right combination of permeability and tension can be developed. Heaving in a clay soil is determined to a great extent by the type of clay and the nature of the ions adsorbed by the clay particles. Heaving can be controlled by lowering the freezing point of the soil water, by restricting the water flow to the freezing front, or by cementing the soil particles together. Chemicals such as calcium chloride have been successful in reducing frost heaving by lowering the freezing point of the soil water. Dispersing agents, mainly sodium compounds, reduce heaving by plugging the soil pores, thus limiting water movement to the freezing front and subsequent growth of ice lenses. Cementing agents make the soil less frost susceptible by reducing the proportion of finer soil particles (clay and silt).


Patent
28 Jun 1976
TL;DR: A tree trunk guying system that permits the flow of vital tree-growing fluids along the cambium layer of the tree trunk and automatically detaches itself from the tree after the tree becomes self-supporting makes use of a unique tree trunk-grasping collar featuring a structure providing both adequate support for and minimal contact with the tree.
Abstract: A tree trunk guying system that permits the flow of vital tree-growing fluids along the cambium layer of the tree trunk and automatically detaches itself from the tree trunk after the tree becomes self-supporting makes use of a unique tree trunk-grasping collar featuring, first, a structure providing both adequate support for and minimal contact with the tree trunk and, second, means for disengaging the tree collar from the tree trunk after a predetermined period of time or predetermined expansion of the tree trunk.

Journal ArticleDOI
01 Jan 1976

Journal ArticleDOI
TL;DR: Chemical analyses of the exudates of Acacia xanthophloea Benth.
Abstract: Many plants of the genus Acacia exude viscous gummy liquids through cuts in their bark. These exudates form clear or translucent masses when exposed to air and function to seal off the injured part of the plant thereby preventing moisture loss and entrance of plant pests or pathogens. Man has capitalized on several unique physical and rheological properties of acacia tree exudates. Gum arabica, for example, is an acacia tree exudate widely used in the food and drug industries. The chemical composition and physical properties of such commercially important acacia gums have been intensively studied (Glicksman, 1969). This note summarizes chemical analyses of the exudates of Acacia xanthophloea Benth. and A . tortilis (Forsk.) Hayne, two of the more common East African acacia trees. Our interest in acacia tree exudates originated in the course of field studies of yellow baboons (Papio cynocephalus L.) in the Amboseli National Park, Kenya (Hausfater, 1975). Two acacia tree species predominate in the central portion of the Park: A. xanthophloea, the yellow-barked acacia or fever tree, is found around swamps and waterholes, A . tortilis, the umbrella tree, is found in drier areas and at slightly higher elevations. Baboons spent long periods of time feeding on the exudate of A . xanthophloea; in contrast, only a few instances of baboons feeding on the exudate of A . tortilis were recorded. Thus, analyses were undertaken to determine if some basic nutritional difference between exudates of these two species accounted for the pattern of selective feeding shown by Amboseli baboons. A. xanthophloea exudes large quantities of a gum from cuts and holes in its bark. The gum is stored in a 2to 6-cm broad band of tubules immediately beneath the outer photosynthetic layer of bark and is readily visible in cross-section in felled trees. The exudate is tasteless and odourless to humans and varies in colour from crystal clear through amber to a deep translucent reddish-brown ; colour is determined by impurities or extraneous substances washed into the exudate, exposure to fire, and tannin incorporated from tissues of the parent tree (Glicksman, 1969). Exudate occurs as droplets, strands, dense nodules up to 15 cm in diameter, or as a broad layer coating the trunk. Exudate of A . tortilis is usually found in much smaller quantities than that of A. xanthophloea. The colour is always a deep reddish brown, darkening with age. Exudate usually appears as a narrow longitudinal streak on trunk or branches, about 4-1 m long and usually less than Q m wide; exudate also often builds up in the litter beneath the tree. To humans, A. tortilis exudate is odourless, but has a somewhat unpleasant taste. This fact, together with its low carbohydrate content (see below), suggests that it is a resin and may contain toxic compounds. Exudate was collected from one or more positions on several trees of both species. Material from trees of the same species was then combined for analysis, including determination of moisture content, ash content, ash composition, and water and benzene solubility. Additionally, the water-soluble fraction from each species was

Proceedings ArticleDOI
S. Lu1, King-Sun Fu1
01 Dec 1976
TL;DR: An error-correcting syntax analyzer for tree languages with substitution errors, called structure-preserved error-Correcting tree automaton (ECTA), is studied.
Abstract: An error-correcting syntax analyzer for tree languages with substitution errors, called structure-preserved error-correcting tree automaton (ECTA), is studied. Substitution errors are defined in terms of transformations which can easily be accommodated to linguistic notion. Let L be a tree language, for a tree s not in L, the essence of ECTA is to search for a tree ? in L such that the cost sequence of error transformations needed to transform ? to s is the minimum among all the sentences in L. A LANDSAT data interpretation problem is used as an example to illustrate the operation of ECTA.

Journal ArticleDOI
TL;DR: A new algorithm for efficiently generating the minimal cut-sets of a fault tree containing repetitions of basic events, which substantially reduces both execution time and storage requirements, over the classical technique, when programmed.
Abstract: This paper presents a new algorithm for efficiently generating the minimal cut-sets of a fault tree containing repetitions of basic events. The algorithm is easily performed by hand and substantially reduces both execution time and storage requirements, over the classical technique, when programmed. The savings are accomplished by recognizing and recursively reducing the influence of the repetitive events. The theoretical basis of the algorithm is presented and examples from the recent literature, used to demonstrate its efficiency. Finally, the computational complexity is discussed and rules presented for simplifying the tree before the computations begin.

01 Aug 1976
TL;DR: Theoretical properties of decision trees whose node decisions are statistically independent are investigated and it is found that under this independence assumption the optimal tree design task is a complex one.
Abstract: : Multistage schemes such as hierarchical classifiers have been found useful for many multiclass pattern recognition tasks This dissertation investigates the theoretical properties of a general model of multistage multiclass recognition schemes The generality of the model allows one to describe a large class of parametric and non-parametric schemes commonly used in terms of the model parameters Hierarchical classifiers are special types of multistage recognition schemes wherein at each stage certain classes are rejected from consideration as labels of the test sample Theoretical properties of decision trees whose node decisions are statistically independent are investigated Even under this independence assumption the optimal tree design task is a complex one

Journal ArticleDOI
David P. Dobkin1
TL;DR: By the method of region counting, a lower bound of n log"2nn queries is obtained onlinear search tree programs which solve the n-dimensional knapsack problem.

Journal ArticleDOI
TL;DR: The main theorem of this paper states that any tree having at least five vertices can be recovered up to isomorphism from its two point deleted subtrees.