Comparison of two parameter recovery methods for the transformation of Pinus sylvestris yield tables into a diameter distribution model

2021 ◽  
Vol 78 (1) ◽  
Author(s):  
Francisco Mauro ◽  
Antonio García-Abril ◽  
Esperanza Ayuga-Téllez ◽  
Alberto Rojo-Alboreca ◽  
Ruben Valbuena ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Distribution Model ◽  
Diameter Distribution ◽  
Parameter Recovery ◽  
Two Parameter ◽  
Recovery Methods

scholarly journals A New Diameter Distribution Model for Unmanaged Loblolly Pine Plantations in East Texas

2006 ◽  
Vol 30 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Young-Jin Lee ◽  
Dean W. Coble
Keyword(s):  
Loblolly Pine ◽  
Pine Plantations ◽  
Growth And Yield ◽  
Distribution Model ◽  
Diameter Distribution ◽  
Yield Prediction ◽  
East Texas ◽  
Distribution Models ◽  
Parameter Recovery ◽  
Diameter Classes

Abstract A parameter recovery procedure for the Weibull distribution function based on four percentile equations was used to develop a diameter distribution yield prediction model for unmanaged loblolly pine (Pinus taeda L.) plantations in East Texas. This model was compared with the diameter distribution models of Lenhart and Knowe, which have been used in East Texas. All three models were evaluated with independent observed data. The model developed in this study performed better than the other two models in prediction of trees per acre and cubic-foot volume per acre (wood and bark, excluding stump) across diameter classes. Lenhart’s model consistently underestimated the larger-diameter classes because it was developed originally with data mostly collected in young plantations. Knowe’s model overestimated volume in sawtimber-sized trees, which could lead to overestimations of volume in older loblolly pine plantations found in East Texas. An example also is provided to show users how to use this new yield prediction system. These results support the recommendation that forest managers should use growth and yield models designed and/or calibrated for the region in which they are implemented.South. J. Appl.For. 30(1):13–20.

scholarly journals A linkage among whole-stand model, individual-tree model and diameter-distribution model

2010 ◽  
Vol 56 (No. 12) ◽  
pp. 600-608 ◽  
Author(s):  
X. Zhang ◽  
Y. Lei
Keyword(s):  
Arithmetic Mean ◽  
Diameter Distribution ◽  
Q Method ◽  
Forecast Combination ◽  
Distribution Models ◽  
Individual Tree ◽  
Parameter Recovery ◽  
Mean Diameter ◽  
Tree Models ◽  
Recovery Methods

Stand growth and yield models include whole-stand models, individual-tree models and diameter-distribution models. In this study, the three models were linked by forecast combination and parameter recovery methods one after another. Individual-tree models combine with whole-stand models through forecast combination. Forecast combination method combines information from different models, disperses errors generated from different models, and then improves forecast accuracy. And then the forecast combination model was linked to diameter-distribution models via parameter recovery methods. During the moment estimation, two methods were used, arithmetic mean diameter and quadratic mean diameter method (A-Q method), and arithmetic mean diameter and diameter variance method (A-V method). Results showed that the forecast combination for predicting stand variables outperformed over the stand-level and tree-level models respectively; A-V method was superior to A-Q method on estimating Weibull parameters; these three different models could be linked very well via forecast combination and parameter recovery.

Performance of Weibull function as a diameter distribution model for Pinus thunbergii stands in the eastern coast of South Korea

2016 ◽  
Vol 13 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Azyleah Cañizares Abino ◽  
Sung Yong Kim ◽  
Roscinto Ian Canicosa Lumbres ◽  
Mi Na Jang ◽  
Ho Joong Youn ◽  
...  
Keyword(s):  
South Korea ◽  
Pinus Thunbergii ◽  
Distribution Model ◽  
Diameter Distribution ◽  
Eastern Coast ◽  
Weibull Function

Statistical Inference of LZL-Type Mass Flowmeter Life Distribution Model

2010 ◽  
Vol 458 ◽  
pp. 173-178
Author(s):  
Zhen Zhou ◽  
L.N. Zhang ◽  
Y. Qin ◽  
D.Z. Ma ◽  
B. Niu
Keyword(s):  
Least Square ◽  
Distribution Model ◽  
Maintenance Policy ◽  
Life Distribution ◽  
Mass Flowmeter ◽  
Failure Data ◽  
Distribution Type ◽  
Two Parameter ◽  
Field Failure ◽  
Type Mass

Characteristics of field failure data are analyzed in this paper. The failure data and sales record of LZL-type mass flowmeter are used to infer life distribution of this conduct. The lines can be fitted in coordinates of six distribution using least square and the residual sum of squares are compared, the minimum correspond is the best distribution type. The results show that the life distribution style of this conduct is the two parameter exponential distribution, which is the base to analyze and predict failure development, research failure mechanism and draw up maintenance policy.

scholarly journals Stand Diameter Distribution Modeling and Prediction Based on Maximum Entropy Principle

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 859 ◽  
Author(s):  
Yuling Chen ◽  
Baoguo Wu ◽  
Zhiqiang Min
Keyword(s):  
Weibull Distribution ◽  
Maximum Entropy ◽  
Measurement Data ◽  
Similarity Index ◽  
Distribution Model ◽  
Diameter Distribution ◽  
Weibull Function ◽  
Prediction Ability ◽  
Actual Distribution ◽  
Modeling And Prediction

Research Highlights: Improving the prediction accuracy represents a popular forest simulation modeling issue, and exploring the optimal maximum entropy (MaxEnt) distribution is a new effective method for improving the diameter distribution model simulation precision to overcome the disadvantages of Weibull. Background and Objectives: The MaxEnt distribution is the closest to the actual distribution under the constraints, which are the main probability density distributions. However, relatively few studies have addressed the optimization of stand diameter distribution based on MaxEnt distribution. The objective of this study was to introduce application of the MaxEnt distribution on modeling and prediction of stand diameter distribution. Materials and Methods: The long-term repeated measurement data sets consisted of 260 diameter frequency distributions from China fir (Cunninghamia lanceolate (Lamb.) Hook) plantations in the southern China Guizhou. The Weibull distribution and the MaxEnt distribution were applied to the fitting of stand diameter distribution, and the modeling and prediction characteristics of Weibull distribution and MaxEnt distribution to stand diameter distribution were compared. Results: Three main conclusions were obtained: (1) MaxEnt distribution presented a more accurate simulation than three-parametric Weibull function; (2) the Chi-square test showed diameter distributions of unknown stands can be well estimated by applying MaxEnt distribution based on the plot similarity index method (PSIM) and Weibull distribution based on the parameter prediction method (PPM); (3) the MaxEnt model can deal with the complex nonlinear relationship and show strong prediction ability when predicting the stand distribution structure. Conclusions: With the increase of sample size, the PSIM has great application prospects in the dynamic prediction system of stand diameter distribution.

Structural stocking guides: a new look at an old friend

2004 ◽  
Vol 34 (5) ◽  
pp. 1044-1056 ◽  
Author(s):  
Jeffrey H Gove
Keyword(s):  
Basal Area ◽  
Primary Objective ◽  
Diameter Distribution ◽  
Minimal Amount ◽  
Forest Types ◽  
Quadratic Mean ◽  
Parameter Recovery ◽  
Distribution Shape ◽  
New Information ◽  
New Type

A parameter recovery-based model is developed that allows the incorporation of diameter distribution information directly into stocking guides. The method is completely general in applicability across different guides and forest types and could be adapted to other systems such as density management diagrams. It relies on a simple measure of diameter distribution shape, the basal area larger than quadratic mean stand diameter, to estimate the parameters of the unknown distribution. This latter quantity is shown to have high correlation with stocking guide variables in northeastern forest types. A primary objective of this new type of guide is that its use should require a minimal amount of new information from the user and that the underlying model should be as simple as possible.

Determination of Drainage Coefficient and Bund Height of Rice Fields at Gaya and Bhagalpur Districts in Bihar

2018 ◽  
Vol 5 (01) ◽  
Author(s):  
ASHUTOSH UPADHYAYA ◽  
S. K. Singh
Keyword(s):  
Return Period ◽  
Agricultural Production ◽  
Water Storage ◽  
Daily Rainfall ◽  
Crop Damage ◽  
Distribution Model ◽  
Return Periods ◽  
Maximum Rainfall ◽  
Two Parameter

Rainfall plays an important role in agricultural production, particularly in rainfed areas. Less occurrence of rainfall causes drought like situation and crops suffer due to deficit of water, whereas heavy rainfall occurring for longer duration lead to flood like situation resulting in more runoff, soil erosion and crop damage. Rice can sustain water for little longer period compared to other crops, but this crop also needs drainage. 30 years daily rainfall data was collected at Gaya and Bhagalpur districts and analyzed. Two parameter Gamma distribution model was found fitting well in 1 to 7 consecutive days maximum rainfall corresponding to return periods varying from 2 to 20 years. In order to determine drainage coefficient at Gaya and Bhagalpur districts, depthduration- return period curves were developed. Tangents were drawn on the curves from 100 mm, 150 mm and 200 mm points and slope of these tangents gave the drainage coefficients corresponding to these rain water storage levels. Since 10 years return period is generally considered in design of agricultural structures, so the poin ton Y axis, where tangent drawn on the curves of 10 years return period crosses, gives the bund height. For both Gaya and Bhagalpur bund heights were found as 24 cm and corresponding drainage coefficients as 12.5 and 25 mm/day.

Reliability Analysis of the Home and Abroad CNC Equipment Used in Automobile Parts Industry

2014 ◽  
Vol 651-653 ◽  
pp. 802-807
Author(s):  
Bin Ma ◽  
Min Luo ◽  
Zhi Chu Chen ◽  
Li Xin Cao
Keyword(s):  
Weibull Distribution ◽  
Empirical Distribution Function ◽  
Least Squares Method ◽  
Empirical Distribution ◽  
Distribution Model ◽  
Parameter Distribution ◽  
Linear Parameter ◽  
Auto Parts ◽  
Fault Information ◽  
Two Parameter

Through analyzing fault information of the home and abroad CNC equipment used in the same auto parts production, the fault data fitting were implemented in this paper. Assuming time between failure probability density function and the empirical distribution function follow the Weibull distribution, A reliability statistical model was built using the least squares method and a linear parameter distribution model regression method. The linear correlation test and the Weibull distribution fault interval obtained show the fact that both the home and abroad equipment are subject to the two parameter Weibull distribution, and after calculating the three indexes of reliability assessment, a conclusion can be made that the reliability of domestic equipment in the study is slightly lower than that of foreign equipment.

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