scholarly journals Criteria to Confirm Models that Simulate Deforestation and Carbon Disturbance

Land ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 105 ◽  
Author(s):  
Robert Pontius
Keyword(s):  
Figure Of Merit ◽  
Operating Characteristic ◽  
Simulation Models ◽  
Forest Degradation ◽  
Random Allocation ◽  
Calibration Period ◽  
Mathematical Properties

The Verified Carbon Standard (VCS) recommends the Figure of Merit (FOM) as a possible metric to confirm models that simulate deforestation baselines for Reducing Emissions from Deforestation and forest Degradation (REDD). The FOM ranges from 0% to 100%, where larger FOMs indicate more-accurate simulations. VCS requires that simulation models achieve a FOM greater than or equal to the percentage deforestation during the calibration period. This article analyses FOM’s mathematical properties and illustrates FOM’s empirical behavior by comparing various models that simulate deforestation and the resulting carbon disturbance in Bolivia during 2010–2014. The Total Operating Characteristic frames FOM’s mathematical properties as a function of the quantity and allocation of simulated deforestation. A leaf graph shows how deforestation’s quantity can be more influential than its allocation when simulating carbon disturbance. Results expose how current versions of the VCS methodologies could conceivably permit models that are less accurate than a random allocation of deforestation, while simultaneously prohibit models that are accurate concerning carbon disturbance. Conclusions give specific recommendations to improve the next version of the VCS methodology concerning three concepts: the simulated deforestation quantity, the required minimum FOM, and the simulated carbon disturbance.

scholarly journals California air resources board forest carbon protocol invalidates offsets

2019 ◽  
Author(s):  
Bruno D V Marino ◽  
Martina Mincheva ◽  
Aaron Doucett
Keyword(s):  
Null Hypothesis ◽  
Geographic Location ◽  
Net Ecosystem Exchange ◽  
Simulation Models ◽  
Forest Degradation ◽  
Scientific Basis ◽  
Forest Carbon ◽  
Carbon Accounting ◽  
Balance Performance ◽  
Commercial Forest

The commercial asset value of sequestered forest carbon is based on protocols employed globally, however, their scientific basis has not been validated. We review and analyze commercial forest carbon protocols and offsets, claimed to have reduced net greenhouse gas emissions, issued by the California Air Resources Board and validated by the Climate Action Reserve (CARB-CAR). CARB-CAR protocol annual offsets, resulting from forest mensuration and growth simulation models, are compared with a population of forest field sites for which annual net ecosystem exchange (NEE) of carbon was measured directly as flux by CO2 eddy covariance, a meteorologically based method integrating forest carbon pools. We characterize differences between the protocols by testing the null hypothesis that the CARB-CAR commercial annual offset data fall within the boundaries of directly measured forest carbon NEE; gC m-2yr-1 are compared for both datasets. Irrespective of geographic location and project type, the CARB-CAR population annual mean value is significantly different from the NEE population mean at the 95% confidence interval, rejecting the null hypothesis. The CARB-CAR population exhibits standard deviation ~5x that of the NEE natural ranges; the variance exceeds the 5% compliance limit for invalidation of CARB-CAR offsets. Exclusion of the soil carbon pool typical for CARB-CAR net carbon budgets pose insuperable carbon accounting uncertainty for offsets that extend to vendor platforms and policies including the United Nations Program on Reducing Emissions from Deforestation and Forest Degradation and the Paris Agreement. NEE methodology for commercial forest carbon offsets ensures in situ molecular specificity, verification of claims for net carbon balance, performance-based pricing and harmonization of carbon protocols for voluntary and compliance markets worldwide, in contrast to continuing uncertainty posed by traditional estimation-based forest carbon protocols.

Comparative Assessment of Safety Indicators for Vehicle Trajectories on Highways

2017 ◽  
Vol 2659 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Freddy Antony Mullakkal-Babu ◽  
Meng Wang ◽  
Haneen Farah ◽  
Bart van Arem ◽  
Riender Happee
Keyword(s):  
Traffic Safety ◽  
Risk Measure ◽  
Simulation Models ◽  
Driving Safety ◽  
Driver Assistance ◽  
Driver Assistance Systems ◽  
Time To Collision ◽  
Vehicle Trajectories ◽  
Mathematical Properties ◽  
Surrogate Safety Measures

Safety measurement and its analysis have been challenging and well-researched topics in transportation. Conventionally, surrogate safety measures have been used as safety indicators in simulation models for safety assessment, in control formulations for driver assistance systems, and in data analysis of naturalistic driving studies. However, surrogate indicators give partial insights on traffic safety; that is, these indicators only indicate a predetermined set of possible precrash situations for an interacting vehicle pair. Recently, a safety indicator called the “driving safety field,” based on field theory, was proposed for two-dimensional vehicle interactions. However, the objectivity of its functional form and its validity have yet to be tested. A qualitative and quantitative comparison of different safety indicators was provided as a risk measure to demarcate their mathematical properties and evaluate their usefulness in quantifying trajectory risk. Five relevant safety indicators were compared: inverse time to collision, postencroachment time, potential indicator of collision with urgent decceleration, warning index, and safety field force. Their formulations were mathematically analyzed to yield qualitative insights and their values over simulated vehicle trajectories were evaluated to yield quantitative insights. The results acknowledge the limitations and demarcate the functional utilities of the selected safety indicators.

scholarly journals California air resources board forest carbon protocol invalidates offsets

2019 ◽  
Author(s):  
Bruno D V Marino ◽  
Martina Mincheva ◽  
Aaron Doucett
Keyword(s):  
Null Hypothesis ◽  
Geographic Location ◽  
Net Ecosystem Exchange ◽  
Simulation Models ◽  
Forest Degradation ◽  
Scientific Basis ◽  
Forest Carbon ◽  
Carbon Accounting ◽  
Balance Performance ◽  
Commercial Forest

The commercial asset value of sequestered forest carbon is based on protocols employed globally, however, their scientific basis has not been validated. We review and analyze commercial forest carbon protocols and offsets, claimed to have reduced net greenhouse gas emissions, issued by the California Air Resources Board and validated by the Climate Action Reserve (CARB-CAR). CARB-CAR protocol annual offsets, resulting from forest mensuration and growth simulation models, are compared with a population of forest field sites for which annual net ecosystem exchange (NEE) of carbon was measured directly as flux by CO2 eddy covariance, a meteorologically based method integrating forest carbon pools. We characterize differences between the protocols by testing the null hypothesis that the CARB-CAR commercial annual offset data fall within the boundaries of directly measured forest carbon NEE; gC m-2yr-1 are compared for both datasets. Irrespective of geographic location and project type, the CARB-CAR population annual mean value is significantly different from the NEE population mean at the 95% confidence interval, rejecting the null hypothesis. The CARB-CAR population exhibits standard deviation ~5x that of the NEE natural ranges; the variance exceeds the 5% compliance limit for invalidation of CARB-CAR offsets. Exclusion of the soil carbon pool typical for CARB-CAR net carbon budgets pose insuperable carbon accounting uncertainty for offsets that extend to vendor platforms and policies including the United Nations Program on Reducing Emissions from Deforestation and Forest Degradation and the Paris Agreement. NEE methodology for commercial forest carbon offsets ensures in situ molecular specificity, verification of claims for net carbon balance, performance-based pricing and harmonization of carbon protocols for voluntary and compliance markets worldwide, in contrast to continuing uncertainty posed by traditional estimation-based forest carbon protocols.

The Costs of Reduction Emission from Deforestation and Forest Degradation. Concepts and Issues

2019 ◽  
Vol 10 (1) ◽  
pp. 63
Author(s):  
Tri WALUYO ◽  
Kumba DIGDOWISEISO ◽  
El Amry Bermawi PUTERA ◽  
Eko SUGIYANTO
Keyword(s):  
Transaction Costs ◽  
Simulation Models ◽  
Forest Degradation ◽  
Empirical Models ◽  
Opportunity Costs ◽  
Double Counting ◽  
Industrialized Countries ◽  
Counting Problem ◽  
Aggregated Data ◽  
Implementation Costs

This study examines the concept of “Reduction Emission from Deforestation and Forest Degradation” - REDD costs by using the existence costs of Boucher (2008) such as opportunity costs, transaction costs, implementation costs, stabilization costs, and administration costs. In addition, it provides some actual issues of REDD. The study proves that global simulation models yield far higher REDD prices than empirical models, however, they can be criticized for their use of aggregated data and other simplifications. Moreover, adding implementation, administration, stabilization costs into transaction costs could potentially lead to double-counting problem. Finally, REDD is an inexpensive option compared to reducing emissions in the energy sectors of industrialized countries and has a potential to generate substantial benefits in addition to the reduction of greenhouse gas emissions. Yet, it is important for countries to manage these issues that can be potentially defect REDD adoption.

Does mammographic density remain a radiological challenge in the digital era?

2020 ◽  
pp. 028418512093836
Author(s):  
Dana S Al-Mousa ◽  
Mohammad Rawashdeh ◽  
Maram Alakhras ◽  
Kelly M Spuur ◽  
Rula AbuTaimai ◽  
...  
Keyword(s):  
Mammographic Density ◽  
Figure Of Merit ◽  
Operating Characteristic ◽  
Experimental Situation ◽  
Free Response ◽  
Digital Era ◽  
High Mammographic Density ◽  
Zealand College ◽  
Sensitivity Specificity ◽  
Higher Sensitivity

Background The low subject contrast between cancerous and fibroglandular tissue could obscure breast abnormalities. Purpose To investigate radiologists’ performance for detection of breast cancer in low and high mammographic density (MD) when cases are digitally acquired. Material and Methods A test set of 60 digital mammography cases, of which 20 were cancerous, were examined by 17 radiologists. Mammograms were categorized as low (≤50%) or high (>50%) MD and rated for suspicion of malignancy using the Royal Australian and New Zealand College of Radiology (RANZCR) classification system. Radiologist demographics including cases read per year, age, subspecialty, and years of reporting were recorded. Radiologist performance was analyzed by the following metrics: sensitivity; specificity; area under the receiver operating characteristic (ROC) curve (AUC), location sensitivity, and jackknife free-response ROC (JAFROC) figure of merit (FOM). Results Comparing high to low MD cases, radiologists showed a significantly higher sensitivity ( P = 0.015), AUC ( P = 0.003), location sensitivity ( P = 0.002), and JAFROC FOM ( P = 0.001). In high compared to low MD cases, radiologists with <1000 annual reads and radiologists with no mammographic subspecialty had significantly higher AUC, location sensitivity, and JAFROC FOM. Radiologists with ≥1000 annual reads and radiologists with mammography subspecialty demonstrated a significant increase in location sensitivity in high compared to low MD cases. Conclusion In this experimental situation, radiologists’ performance was higher when reading cases with high compared to low MD. Experienced radiologists were able to precisely localize lesions in breasts with higher MD. Further studies in unselected screening materials are needed to verify the results.

Seti Figure of Merit

1997 ◽  
Vol 161 ◽  
pp. 711-717 ◽  
Author(s):  
John W. Dreher ◽  
D. Kent Cullers
Keyword(s):  
Figure Of Merit ◽  
Qualitative Difference ◽  
Current Generation ◽  
Detection Range ◽  
Sky Surveys ◽  
Independent Observations ◽  
Good For

AbstractWe develop a figure of merit for SETI observations which is anexplicitfunction of the EIRP of the transmitters, which allows us to treat sky surveys and targeted searches on the same footing. For each EIRP, we calculate the product of terms measuring the number of stars within detection range, the range of frequencies searched, and the number of independent observations for each star. For a given set of SETI observations, the result is a graph of merit versus transmitter EIRP. We apply this technique to several completed and ongoing SETI programs. The results provide a quantitative confirmation of the expected qualitative difference between sky surveys and targeted searches: the Project Phoenix targeted search is good for finding transmitters in the 109to 1014W range, while the sky surveys do their best at higher powers. Current generation optical SETI is not yet competitive with microwave SETI.

Correlation of Pore Structure and Permeability by SEM-Image Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 428-429
Author(s):  
C. A. Callender ◽  
Wm. C. Dawson ◽  
J. J. Funk
Keyword(s):  
Image Analysis ◽  
Pore Structure ◽  
Imaging System ◽  
Pore Space ◽  
Simulation Models ◽  
Image Analyzer ◽  
Imaging Data ◽  
Sem Images ◽  
Thin Sections ◽  
Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

Arterial stiffness is a potential mechanism and promising indicator of orthostatic hypotension in the general population

VASA ◽  
2014 ◽  
Vol 43 (6) ◽  
pp. 423-432 ◽  
Author(s):  
Qingtao Meng ◽  
Si Wang ◽  
Yong Wang ◽  
Shixi Wan ◽  
Kai Liu ◽  
...  
Keyword(s):  
General Population ◽  
Arterial Stiffness ◽  
Orthostatic Hypotension ◽  
Operating Characteristic ◽  
Pulse Wave ◽  
Augmentation Index ◽  
Multiple Logistic Regression Analysis ◽  
The Elderly ◽  
Baroreceptor Sensitivity ◽  
Roc Curve Analysis

Background: Orthostatic hypotension (OH) is a disease prevalent among middle-aged men and the elderly. The association between arterial stiffness and OH is unclear. This study evaluates whether arterial stiffness is correlated with OH and tests the usefulness of brachial-ankle pulse wave velocity (baPWV), an arterial stiffness marker, with regard to identifying OH. Patients and methods: A sample of 1,010 participants was recruited from the general population (64.8 ± 7.7 years; 426 men) who attended health check-ups. BaPWV and the radial augmentation index (rAI) were both assessed as the arterial stiffness markers, and OH was determined using blood pressure (BP) measured in the supine position, as well as 30 seconds and 2 minutes after standing. Results: The prevalence of OH in this population was 4.9 %. Compared with the non-OH group, both baPWV (20.5 ± 4.5 vs 17.3 ± 3.7, p < 0.001) and rAI (88.1 ± 10.8 vs 84.2 ± 10.7, p < 0.05) were significantly higher in the OH group. In the multiple logistic regression analysis, baPWV (OR, 1.3; 95 % CI, 1.106–1.528; p < 0.05) remained associated with OH. Moreover, the degree of orthostatic BP reduction was related to arterial stiffness. In addition, increases in arterial stiffness predicted decreases in the degree of heart rate (HR) elevation. Finally, a receiver operating characteristic (ROC) curve analysis showed that baPWV was useful in discriminating OH (AUC, 0.721; p < 0.001), with the cut-off value of 18.58 m/s (sensitivity, 0.714; specificity, 0.686). Conclusions: Arterial stiffness determined via baPWV, rather than rAI, was significantly correlated with the attenuation of the orthostatic hemodynamic response and the resultant OH. The impaired baroreceptor sensitivity might be the mechanism. In addition, baPWV appears to be a relatively sensitive and reliable indicator of OH in routine clinical practice.

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