scholarly journals Testing the Performance of Some Competition Indices against Experimental Data and Outputs of Spatially Explicit Simulation Models

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1415
Author(s):  
Vladimir Shanin ◽  
Hannu Hökkä ◽  
Pavel Grabarnik
Keyword(s):  
Experimental Data ◽  
Simulation Models ◽  
Spatially Explicit ◽  
Dynamics Modeling ◽  
Explicit Simulation ◽  
Individual Trees ◽  
Spatial Locations ◽  
Explicit Process ◽  
Competition Indices ◽  
Process Based Models

Three competition indices were tested against experimental data on the growth of individual trees in mapped forest stands and outputs of spatially explicit, process-based models of competition. The comparison showed the fundamental importance of taking into account the spatial structure of stands and, particularly, the relative spatial locations of individual trees (spatial asymmetry) when calculating the competition between trees. Although none of the competition indices are able to take into account the specific processes affecting the development of individual trees, these indices can be used in forest dynamics modeling as a simplified representation of competition between trees for resources.

scholarly journals Modelling the impact of poaching on metapopulation viability for data-limited species

2017 ◽  
Vol 74 (6) ◽  
pp. 894-906 ◽  
Author(s):  
Abbey E. Camaclang ◽  
Janelle M.R. Curtis ◽  
Ilona Naujokaitis-Lewis ◽  
Mark S. Poesch ◽  
Marten A. Koops
Keyword(s):  
Management Strategies ◽  
Simulation Models ◽  
Sensitivity Analyses ◽  
Future Research ◽  
Spatially Explicit ◽  
Barkley Sound ◽  
Spatially Explicit Population Model ◽  
Future Research Directions ◽  
Explicit Simulation ◽  
The Impact

We developed a spatially explicit simulation model of poaching behaviour to quantify the relative influence of the intensity, frequency, and spatial distribution of poaching on metapopulation viability. We integrated our model of poaching with a stochastic, habitat-based, spatially explicit population model, applied it to examine the impact of poaching on northern abalone (Haliotis kamtschatkana) metapopulation dynamics in Barkley Sound, British Columbia, Canada, and quantified model sensitivity to input parameters. While demographic parameters remained important in predicting extinction probabilities for northern abalone, our simulations indicate that the odds of extinction are twice as high when populations are subjected to poaching. Viability was influenced by poaching variables that affect the total number of individuals removed. Of these, poaching mortality was the most influential in predicting metapopulation viability, with each 0.1 increase in mortality rate resulting in 22.6% increase in the odds of extinction. By contrast, the location and spatial correlation of events were less important predictors of viability. When data are limited, simulation models of poaching combined with sensitivity analyses can be useful in informing management strategies and future research directions.

Spatially Explicit Simulation of Soil C Dynamics with the Century Model

2008 ◽  
Author(s):  
Carlos Gustavo Tornquist ◽  
Joao Mielnickzuk ◽  
Philip Walter Gassman
Keyword(s):  
Spatially Explicit ◽  
Century Model ◽  
Soil C ◽  
C Dynamics ◽  
Explicit Simulation

An Object-Oriented Approach to Managing Fuzziness in Spatially Explicit Models Coupled to a Geographic Database

2011 ◽  
pp. 269-300 ◽  
Author(s):  
Vincent B. Robinson ◽  
Phil A. Graniero
Keyword(s):  
Spatial Data ◽  
Spatial Databases ◽  
Ecological Modeling ◽  
Simulation Models ◽  
Spatially Explicit ◽  
Loosely Coupled ◽  
Spatially Explicit Models ◽  
Modeling Problem ◽  
Object Oriented Approach ◽  
Oriented Approach

This chapter uses a spatially explicit, individual-based ecological modeling problem to illustrate an approach to managing fuzziness in spatial databases that accommodates the use of nonfuzzy as well as fuzzy representations of geographic databases. The approach taken here uses the Extensible Component Objects for Constructing Observable Simulation Models (ECO-COSM) system loosely coupled with geographic information systems. ECO-COSM Probe objects flexibly express the contents of a spatial database within the context of an individualized fuzzy schema. It affords the ability to transform traditional nonfuzzy spatial data into fuzzy sets that capture the uncertainty inherent in the data and model’s semantic structure. The ecological modeling problem was used to illustrate how combining Probes and ProbeWrappers with Agent objects affords a flexible means of handling semantic variation and is an effective approach to utilizing heterogeneous sources of spatial data.

Simulation of Stacked Quantum Dot Channels SWS-FET Using Multi-FET ABM Modeling

2019 ◽  
Vol 28 (03n04) ◽  
pp. 1940025
Author(s):  
H. Salama ◽  
B. Saman ◽  
R. H. Gudlavalleti ◽  
P-Y. Chan ◽  
R. Mays ◽  
...  
Keyword(s):  
Experimental Data ◽  
Quantum Dot ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Simulation Models ◽  
Logic Gates ◽  
Behavior Model ◽  
Analog Behavior

This paper presents simulation of spatial wavefunction switched (SWS) field-effect transistors (FETs) comprising of two vertically stacked quantum dot channels. An analog behavior model (ABM) was used to compare the experimental I-V characteristics of a fabricated QD-SWS-FET. Each channel consists of two quantum dot layers and are connected to the dedicated drains D2 and D1, respectively. The fabricated SWS-FET has one source and one gate. The ABM simulation models SWS-FET comprising of two independent conventional BSIM FETs with their (W/L) ratios, capacitances and other device parameters. The agreement in simulation and experimental data will advance modeling of SWS based adders, logic gates and SRAMs.

Development and Use of Bounding Functions in a Forest Growth Model

1993 ◽  
Vol 8 (1) ◽  
pp. 24-27
Author(s):  
K. Leroy Dolph ◽  
Gary E. Dixon
Keyword(s):  
Computer Simulation ◽  
Simulation Models ◽  
Height Growth ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Growth Model ◽  
Individual Trees ◽  
Computer Simulation Models ◽  
Forest Growth And Yield

Abstract Erroneous predictions of forest growth and yield may result when computer simulation models use extrapolated data in repeated or long-term projections or if the models are used outside the range of data on which they were built. Bounding functions that limit the predicted diameter and height growth of individual trees to maximum observed values were developed to constrain these erroneous predictions in a forest growth and yield simulator. Similar techniques could be useful for dealing with extrapolated data in other types of simulation models. West. J. Appl. For. 8(1):24-27.

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