Using portable laser EDM for forest traverse surveys

1995 ◽  
Vol 25 (5) ◽  
pp. 753-766 ◽  
Author(s):  
C.J. Liu
Keyword(s):  
Adverse Effects ◽  
Field Measurement ◽  
Experimental Tests ◽  
Cost Effective ◽  
Distance Measurement ◽  
Forest Stand ◽  
Forest Stands ◽  
Laser Technology ◽  
Electronic Distance Measurement ◽  
Area Determination

A new electronic distance measurement (EDM) device that utilizes laser technology for tree measurement and surveying was used to study traverse surveys of forest stands. Experimental tests demonstrated that the laser EDM device afforded (1) an allowable angular closure error of 3°, (2) an average linear closure precision of 1/550 for a bidirectional traverse and of 1/470 for a unidirectional traverse, (3) an average traversing speed of 0.25 mi/h (0.40 km/h) for bidirectional traverses, and (4) an average surveying rate of 6 acres/h (2.4 ha/h). The study also showed that (1) the digital laser EDM device was 10 times more cost effective than the traditional analogous surveying equipment and (2) a unidirectional traverse is, on the average, 1.5 times more effective than a bidirectional traverse. Additional analyses revealed that the interior angle adjustment (IAA) procedure consistently altered the shape of the stand and changed the stand area. These findings led to several suggestions: (1) the laser EDM device should be adopted for forest stand traverse surveys because it is easy to use, accurate, and cost effective; (2) the routine of taking backsight in field measurement provides little gain in accuracy in stand area determination and should be exercised only when local magnetic interference is expected to adversely affect compass accuracy; and (3) the conventional practice of IAA prior to balancing the traverse should not be exercised, since this procedure has adverse effects on mapping and area determination.

Using differential GPS for forest traverse surveys

1995 ◽  
Vol 25 (11) ◽  
pp. 1795-1805 ◽  
Author(s):  
C.J. Liu ◽  
Richard (Dick) Brantigan
Keyword(s):  
Forest Canopy ◽  
Cost Effective ◽  
Hardwood Forests ◽  
Forest Stand ◽  
Differential Gps ◽  
Mountainous Regions ◽  
Effectiveness Analysis ◽  
Definite Effect ◽  
Survey Technique ◽  
Area Determination

This report documents the accuracy and efficiency of differential GPS (DGPS) when it is applied in forest environments. The report contains research results obtained from using DGPS for forest-stand boundary surveys conducted in hardwood forests in a mountainous region. Reported also is the result of a cost-effectiveness analysis that contrasts the satellite-based DGPS positioning and the conventional land-based compass-and-chain surveys. The study found that (1) both forest canopy and undulating terrain in mountainous regions would exert a definite effect on DGPS traverse surveys but neither would reduce stand area determination accuracy; (2) in general, static DGPS was more accurate but less productive than the kinematic DGPS when accuracy and cost were weighted equally; (3) inaccurate two-dimensional position determinations degraded positioning accuracy in either the kinematic or static positioning mode; and (4) kinematic DGPS traverse was a cost-effective survey technique capable of achieving closer forest stand area approximation than the compass-and-chain traverse.

Guides for Estimating Forest Stand Losses to Gypsy Moth

1984 ◽  
Vol 1 (2) ◽  
pp. 21-23 ◽  
Author(s):  
David A. Gansner ◽  
Owen W. Herrick
Keyword(s):  
Species Composition ◽  
Gypsy Moth ◽  
Tree Mortality ◽  
Cost Effective ◽  
Forest Stand ◽  
Measure Data ◽  
Effective Management ◽  
Field Plot ◽  
Crown Condition ◽  
As Species

Abstract People who have to make decisions about cost-effective management for gypsy moth need help in predicting and evaluating its effects. Field plot data collected during recent outbreaks in Pennsylvania are being used to develop guides for predicting forest stand losses to the pest Presented here are some of the more useful products of that effort to date. Easy-to-measure data for forest characteristics such as species composition and crown condition can be collected and applied in models that estimate potential stand and tree mortality and changes in timber value. North. J. Appl. For. 2:21-23, June 1984.

Modelling growing stock volume of forest stands with various ALS area-based approaches

2021 ◽  
Author(s):  
Karolina Parkitna ◽  
Grzegorz Krok ◽  
Stanisław Miścicki ◽  
Krzysztof Ukalski ◽  
Marek Lisańczuk ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Mean Squared Error ◽  
Prediction Method ◽  
Forest Stand ◽  
Boosted Regression Trees ◽  
Forest Stands ◽  
Individual Tree ◽  
Growing Stock ◽  
Modelling Techniques ◽  
Stock Volume

Abstract Airborne laser scanning (ALS) is one of the most innovative remote sensing tools with a recognized important utility for characterizing forest stands. Currently, the most common ALS-based method applied in the estimation of forest stand characteristics is the area-based approach (ABA). The aim of this study was to analyse how three ABA methods affect growing stock volume (GSV) estimates at the sample plot and forest stand levels. We examined (1) an ABA with point cloud metrics, (2) an ABA with canopy height model (CHM) metrics and (3) an ABA with aggregated individual tree CHM-based metrics. What is more, three different modelling techniques: multiple linear regression, boosted regression trees and random forest, were applied to all ABA methods, which yielded a total of nine combinations to report. An important element of this work is also the empirical verification of the methods for estimating the GSV error for individual forest stand. All nine combinations of the ABA methods and different modelling techniques yielded very similar predictions of GSV for both sample plots and forest stands. The root mean squared error (RMSE) of estimated GSV ranged from 75 to 85 m3 ha−1 (RMSE% = 20.5–23.4 per cent) and from 57 to 64 m3 ha−1 (RMSE% = 16.4–18.3 per cent) for plots and stands, respectively. As a result of the research, it can be concluded that GSV modelling with the use of different ALS processing approaches and statistical methods leads to very similar results. Therefore, the choice of a GSV prediction method may be more determined by the availability of data and competences than by the requirement to use a particular method.

scholarly journals Experimental Strain Measurement Approach Using Fiber Bragg Grating Sensors for Monitoring of Railway Switches and Crossings

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3639
Author(s):  
Abdelfateh Kerrouche ◽  
Taoufik Najeh ◽  
Pablo Jaen-Sola
Keyword(s):  
Fiber Bragg Grating ◽  
Experimental Tests ◽  
Cost Effective ◽  
Measuring Method ◽  
Bragg Grating ◽  
Railway Network ◽  
System Failures ◽  
Railway Infrastructure ◽  
Train Speed ◽  
And Control

Railway infrastructure plays a major role in providing the most cost-effective way to transport freight and passengers. The increase in train speed, traffic growth, heavier axles, and harsh environments make railway assets susceptible to degradation and failure. Railway switches and crossings (S&C) are a key element in any railway network, providing flexible traffic for trains to switch between tracks (through or turnout direction). S&C systems have complex structures, with many components, such as crossing parts, frogs, switchblades, and point machines. Many technologies (e.g., electrical, mechanical, and electronic devices) are used to operate and control S&C. These S&C systems are subject to failures and malfunctions that can cause delays, traffic disruptions, and even deadly accidents. Suitable field-based monitoring techniques to deal with fault detection in railway S&C systems are sought after. Wear is the major cause of S&C system failures. A novel measuring method to monitor excessive wear on the frog, as part of S&C, based on fiber Bragg grating (FBG) optical fiber sensors, is discussed in this paper. The developed solution is based on FBG sensors measuring the strain profile of the frog of S&C to determine wear size. A numerical model of a 3D prototype was developed through the finite element method, to define loading testing conditions, as well as for comparison with experimental tests. The sensors were examined under periodic and controlled loading tests. Results of this pilot study, based on simulation and laboratory tests, have shown a correlation for the static load. It was shown that the results of the experimental and the numerical studies were in good agreement.

The optimal rotation of a flammable forest stand

1980 ◽  
Vol 10 (1) ◽  
pp. 30-34 ◽  
Author(s):  
D. L. Martell
Keyword(s):  
Stochastic Model ◽  
Fire Management ◽  
Jack Pine ◽  
Forest Stand ◽  
Timber Production ◽  
Forest Stands ◽  
Rotation Interval ◽  
Optimal Rotation

The author describes a stochastic model of forest stand rotation which can be used to determine the optimal planned rotation interval for flammable forest stands. The model can also be used to estimate the value of fire management activities in terms of the potential enhanced value of timber production. The use of the model is illustrated by applying it to a simplified case of jack pine (Pinusbanksiana, Lamb.) management.

Design and Analysis of Automotive Bumper Covers in Transient Loading Conditions

2016 ◽  
Vol 715 ◽  
pp. 174-179 ◽  
Author(s):  
Chih Hsing Liu ◽  
Ying Chia Huang ◽  
Chen Hua Chiu ◽  
Yu Cheng Lai ◽  
Tzu Yang Pai
Keyword(s):  
Optimal Design ◽  
Numerical Model ◽  
Design Method ◽  
Experimental Tests ◽  
Cost Effective ◽  
Limited Range ◽  
Optimization Approach ◽  
Loading Conditions ◽  
Element Analysis ◽  
Design Guideline

This paper presents the analysis methods for design of automotive bumper covers. The bumper covers are plastic structures attached to the front and rear ends of an automobile and are expected to absorb energy in a minor collision. One requirement in design of the bumper covers is to minimize the bumper deflection within a limited range under specific loadings at specific locations based on the design guideline. To investigate the stiffness performance under various loading conditions, a numerical model based on the explicit dynamic finite element analysis (FEA) using the commercial FEA solver, LS-DYNA, is developed to analyze the design. The experimental tests are also carried out to verify the numerical model. The thickness of the bumper cover is a design variable which usually varies from 3 to 4 mm depending on locations. To improve the stiffness of the bumper, an optimal design for the bumper under a pre-defined loading condition is identified by using the topology optimization approach, which is an optimal design method to obtain the optimal layout of an initial design domain under specific boundary conditions. The outcome of this study provides an efficient and cost-effective method to predict and improve the design of automotive bumper covers.

Calibration baselines in canada

CISM journal ◽  
1988 ◽  
Vol 42 (3) ◽  
pp. 207-215
Author(s):  
D. Gillis ◽  
L. Nabe
Keyword(s):  
Geodetic Survey ◽  
Distance Measurement ◽  
Joint Program ◽  
Length Standard ◽  
Electronic Distance Measurement

The establishing, measuring and monitoring of Electronic Distance Measurement (EDM) cali¬bration baselines in Canada is a joint program of the Geodetic Survey of Canada and provincial, territorial and municipal surveying agencies. Since its establishment in 1971, the 2.3 km National Geodetic Baseline (NGBL) in Ottawa has been used as the reference baseline for other calibration baselines; two precise EDM instruments, the Mekometer ME3000 and the Geomensor CR204, have been used to transfer the length standard of the NGBL to baselines across Cana¬da. Thirty-six calibration baselines, established as part of the National Baseline Program, now exist. The Geodetic Survey strives to maintain the published values of interpier distances at the highest accuracy possible. To this end, extensive remeasurements are being planned. For longer distances which may be required to calibrate or check GPS instruments, a calibration network with lines up to 222 km is being established.

Pleural Effusions: Pathophysiology and Management

1994 ◽  
Vol 28 (7-8) ◽  
pp. 894-903 ◽  
Author(s):  
Carlota O. Andrews ◽  
Mary Lea Gora
Keyword(s):  
Adverse Effects ◽  
English Language ◽  
Treatment Options ◽  
Cost Effective ◽  
Underlying Disease ◽  
Pleural Space ◽  
Pleural Effusions ◽  
Medline Search ◽  
Sclerosing Agents ◽  
Study Selection

OBJECTIVE: To review the pathophysiology and management of pleural effusions, including available agents for pleural sclerosis. DATA SOURCES: A MEDLINE search (1966 to present) was performed that included clinical studies in the English language involving the pathophysiology and management of pleural effusions; references used in those articles were screened for additional published information. STUDY SELECTION: All clinical trials were considered for potential inclusion in the review. DATA SYNTHESIS: Pleural effusion is an accumulation of fluid in the pleural space that results when homeostatic forces that control the flow into and out of the area are disrupted. The management of transudative pleural effusions is primarily directed at treatment of the underlying disease. There are several treatment options for pleural effusions, including chemical pleurodesis. Many of the trials that examine the use of talc, bleomycin, and doxycycline have poorly described study designs and end points, with inconsistent evaluation of patients. Each agent is considered to be generally effective and safe, with fever and pain as the most frequently reported adverse effects. The use of talc requires sterilization, and many clinicians use general anesthesia with instillation, which increases the risk associated with the procedure. Bleomycin is generally safe; however, it should not be used in doses exceeding 40 mg/m2. Only uncontrolled trials support the use of doxycycline; however, it provides an effective, safe, and relatively inexpensive alternative. CONCLUSIONS: Pleural effusions are defined as an accumulation of fluid in the pleural space. Treatment is generally palliative. Intrapleural administration of talc, bleomycin, and doxycycline are effective sclerosing agents for treatment of recurrent, symptomatic pleural effusions. Although the most cost-effective agent has not been determined, doxycycline is an inexpensive alternative to bleomycin, and may have fewer adverse effects than talc.

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