New application of a polynomial curve to plot volume estimation

1994 ◽  
Vol 24 (6) ◽  
pp. 1083-1088 ◽  
Author(s):  
W.T. Zakrzewski ◽  
M. Ter-Mikaelian

This paper presents a new method of plot volume estimation using a limited sample of heights. It requires measurement of all diameters in the plot and a limited number of height measurements per plot within a plot-specific diameter class predefined by the method. It also requires a diameter-based description of tree form. The method utilizes a polynomial curve to relate heights and diameters, but does not provide information on the plot height structure in the form of a traditional height–diameter curve. The approach was examined using data from north-central Ontario jack pine (Pinusbanksiana Lamb.) stands. The developed method of stand volume estimation is precise and unbiased with respect to height measurements; it reduces laborious height measurements compared with traditional methods utilizing a height–diameter curve.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Elisabeth A. Rosenthal ◽  
David R. Crosslin ◽  
Adam S. Gordon ◽  
David S. Carrell ◽  
Ian B. Stanaway ◽  
...  

Abstract Background Elevated triglycerides (TG) are associated with, and may be causal for, cardiovascular disease (CVD), and co-morbidities such as type II diabetes and metabolic syndrome. Pathogenic variants in APOA5 and APOC3 as well as risk SNVs in other genes [APOE (rs429358, rs7412), APOA1/C3/A4/A5 gene cluster (rs964184), INSR (rs7248104), CETP (rs7205804), GCKR (rs1260326)] have been shown to affect TG levels. Knowledge of genetic causes for elevated TG may lead to early intervention and targeted treatment for CVD. We previously identified linkage and association of a rare, highly conserved missense variant in SLC25A40, rs762174003, with hypertriglyceridemia (HTG) in a single large family, and replicated this association with rare, highly conserved missense variants in a European American and African American sample. Methods Here, we analyzed a longitudinal mixed-ancestry cohort (European, African and Asian ancestry, N = 8966) from the Electronic Medical Record and Genomics (eMERGE) Network. We tested associations between median TG and the genes of interest, using linear regression, adjusting for sex, median age, median BMI, and the first two principal components of ancestry. Results We replicated the association between TG and APOC3, APOA5, and risk variation at APOE, APOA1/C3/A4/A5 gene cluster, and GCKR. We failed to replicate the association between rare, highly conserved variation at SLC25A40 and TG, as well as for risk variation at INSR and CETP. Conclusions Analysis using data from electronic health records presents challenges that need to be overcome. Although large amounts of genotype data is becoming increasingly accessible, usable phenotype data can be challenging to obtain. We were able to replicate known, strong associations, but were unable to replicate moderate associations due to the limited sample size and missing drug information.


1995 ◽  
Vol 25 (11) ◽  
pp. 1783-1794 ◽  
Author(s):  
Thomas B. Lynch

Three basic techniques are proposed for reducing the variance of the stand volume estimate provided by cylinder sampling and Ueno's method. Ueno's method is based on critical height sampling but does not require measurement of critical heights. Instead, a count of trees whose critical heights are less than randomly generated heights is used to estimate stand volume. Cylinder sampling selects sample trees for which randomly generated heights fall within cylinders formed by tree heights and point sampling plot sizes. The methods proposed here for variance reduction in cylinder sampling and Ueno's method are antithetic variates, importance sampling, and control variates. Cylinder sampling without variance reduction was the most efficient of 12 methods compared in computer simulation that used estimated measurement times. However, cylinder sampling requires knowledge of a combined variable individual tree volume equation. Of the three variance reduction techniques applied to Ueno's method, antithetic variates performed best in computer simulation.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Ana Paula Henriques de Gusmão ◽  
Cristina Pereira Medeiros

This paper arose from the perceived need to make a contribution towards assessing a strategic information system by using a new method for eliciting the weights of criteria. This is considered one of the most complex and important stages in multicriteria models. Multicriteria models have been proposed to support decisions in the context of information systems given that problems in this field deal with many conflicting criteria. The new procedure for eliciting the weights of the criteria has the advantage of requiring less effort from the decision-maker and, thus, the risk of inconsistent answers is minimized. Therefore, a model based on this new procedure is proposed and applied using data from a glass packaging factory that needs to select a single information system from a set of systems previously identified as relevant. The results obtained are consistent both with the performance of alternatives and with the additive model used to evaluate the alternatives.


1999 ◽  
Vol 16 (4) ◽  
pp. 219-225 ◽  
Author(s):  
Don Tustin

AbstractFunctional analysis is used to identify potential reinforcers by generating hypotheses about possible functions of a behaviour. Current methods of functional analysis emphasise observations of events, especially consequences, that occur in the immediate environment of the behaviour. While these methods are well suited for assessing behaviour that is reinforced frequently, they are less appropriate for assessing behaviour that is reinforced only intermittently. A new method for conducting functional analysis is presented that is designed to assess intermittently reinforced behaviour. The new method is illustrated using data that were gathered from an extension of a standard problem-solving format. Data are interpreted using the principle of revealed preference that arose from behavioural economics. The revealed preference method is illustrated using information provided by a client with a dependent personality disorder.


2018 ◽  
Vol 14 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Anna Fitzpatrick ◽  
Joseph A Stone ◽  
Simon Choppin ◽  
John Kelley

Performance analysis and identifying performance characteristics associated with success are of great importance to players and coaches in any sport. However, while large amounts of data are available within elite tennis, very few players employ an analyst or attempt to exploit the data to enhance their performance; this is partly attributable to the considerable time and complex techniques required to interpret these large datasets. Using data from the 2016 and 2017 French Open tournaments, we tested the agreement between the results of a simple new method for identifying important performance characteristics (the Percentage of matches in which the Winner Outscored the Loser, PWOL) and the results of two standard statistical methods to establish the validity of the simple method. Spearman’s rank-order correlations between the results of the three methods demonstrated excellent agreement, with all methods identifying the same three performance characteristics ( points won of 0–4 rally length, baseline points won and first serve points won) as strongly associated with success. Consequently, we propose that the PWOL method is valid for identifying performance characteristics associated with success in tennis, and is therefore a suitable alternative to more complex statistical methods, as it is simpler to calculate, interpret and contextualise.


2021 ◽  
Vol 62 (2) ◽  
pp. 255-262
Author(s):  
D.A. Kuleshov ◽  
P.G. Dyadkov ◽  
V.V. Plotkin

Abstract ––The study focuses on detection of geomagnetic secular variation and the respective correction of tectonomagnetic data. A new technique is proposed for picking the secular variation component in the Earth’s main magnetic field recorded by precise measurements at 100 to 500 km sites on the surface. Long-period field variations presumably arise from fluid motions in the liquid core, at depths of 3000 km, whereas the sizes of observation networks are within 500 km. The sources of secular variation, irrespective of their configuration, are much deeper than those of tectonomagnetic anomalies located above the Curie surface depths of ~10 to 20 km. Therefore, the surfaces that represent the space distribution of secular variation must be smoother than the respective surfaces for tectonomagnetic anomalies. The problem is thus to separate the regional and local signals from the two types of sources located at different depths. The new method is tested using data of yearly geomagnetic measurements at more than 30 repeat stations of a ~120 km long geodynamic network in Gorny Altai spanning the period from 2004 through 2018. The secular variation pattern is reconstructed by quadratic interpolation. The precise data corrected for secular variation of the main field reveal previously hidden tectonomagnetic anomalies up to 12 nT. The 3 nT positive anomaly falls within the zone of surface deformation caused by the Mw = 7.3 Chuya earthquake of 27 September 2003.


2008 ◽  
Vol 22 (5) ◽  
pp. 654-662 ◽  
Author(s):  
A. A. Obwegeser ◽  
R. J. Uitti ◽  
J. A. Lucas ◽  
R. J. Witte ◽  
M. F. Turk ◽  
...  
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1990 ◽  
Vol 20 (3) ◽  
pp. 274-279 ◽  
Author(s):  
Thomas B. Lynch

Stand volume estimators are developed in the context of vertical line sampling that depend on counts of sample trees only, rather than on measurements of sample tree dimensions. These estimators are based on three commonly used individual tree volume equations: the constant form factor volume equation, the combined variable volume equation with negative intercept, and the combined variable volume equation with positive intercept. Fieldwork for each of the estimators involves comparison of the squared dbh's of trees that would qualify for selection in an ordinary vertical line sample with numbers chosen randomly from the interval bounded by zero and a fixed maximum squared dbh. Two of the estimators choose sample trees with probability exactly proportional to an individual tree volume equation.


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