Simple Simulation

When social scientists wish to learn about an empirical phenomenon, they perform an experiment. When they wish to learn about a complex numerical phenomenon, they can perform a simulation study. The goal of this Tutorial is twofold. First, it introduces how to set up a simulation study using the relatively simple example of simulating from the prior. Second, it demonstrates how simulation can be used to learn about the Jeffreys-Zellner-Siow (JZS) Bayes factor, a currently popular implementation of the Bayes factor employed in the BayesFactor R package and freeware program JASP. Many technical expositions on Bayes factors exist, but these may be somewhat inaccessible to researchers who are not specialized in statistics. In a step-by-step approach, this Tutorial shows how a simple simulation script can be used to approximate the calculation of the Bayes factor. We explain how a researcher can write such a sampler to approximate Bayes factors in a few lines of code, what the logic is behind the Savage-Dickey method used to visualize Bayes factors, and what the practical differences are for different choices of the prior distribution used to calculate Bayes factors.

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Changes in mean forest age in Canada’s forests could limit future increases in area burned but compromise potential harvestable conifer volumes

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0445 ◽

2017 ◽

Vol 47 (6) ◽

pp. 755-764 ◽

Cited By ~ 18

Author(s):

Yan Boulanger ◽

Martin Girardin ◽

Pierre Y. Bernier ◽

Sylvie Gauthier ◽

André Beaudoin ◽

...

Keyword(s):

Simulation Models ◽

Stand Age ◽

Almost Everywhere ◽

Age Related ◽

New Information ◽

Simple Simulation ◽

Regional Vulnerability ◽

Vegetation Feedbacks ◽

Burning Rates ◽

Negative Impacts

Forest fire activity is projected to increase with climate change in Canada, but vegetation feedbacks are usually not considered. Using new information on the selectivity or avoidance of fire as a function of stand age and composition, we ran simple simulation models that consider the changes in the regional age matrices induced by fire and harvesting to project future burn rates. We also projected estimated future regional vulnerability of timber supply to fire by considering these new burn rates. The inclusion of age-related feedbacks would have a large impact on projected increases in burn rates, mostly in a very fire active zone under aggressive climate forcing. Projected burn rates would still increase, but would be 50% less in 2100 than if projected without this biotic feedback in some zones. Negative feedbacks would be virtually nonexistent when potential burning rates are below 1%, whereas realized burning rates would be lowered by more than a 0.5 percentage point when potential burning rates exceed 2.5%. Including fire–vegetation feedbacks had virtually no impact on total volume harvested. As fire burns more old-growth coniferous stands, slightly negative impacts were projected on conifer harvested almost everywhere. These results underline the need to incorporate fire–vegetation feedbacks when projecting future burn rates.

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A Simulation of the Structure of the World-Wide Web

Sociological Research Online ◽

10.5153/sro.684 ◽

2002 ◽

Vol 7 (1) ◽

pp. 9-25 ◽

Cited By ~ 2

Author(s):

Moses Boudourides ◽

Gerasimos Antypas

Keyword(s):

World Wide Web ◽

Power Law ◽

Web Sites ◽

World Wide ◽

The Internet ◽

Web Pages ◽

Small Worlds ◽

Web Page ◽

Simple Simulation ◽

The World

In this paper we are presenting a simple simulation of the Internet World-Wide Web, where one observes the appearance of web pages belonging to different web sites, covering a number of different thematic topics and possessing links to other web pages. The goal of our simulation is to reproduce the form of the observed World-Wide Web and of its growth, using a small number of simple assumptions. In our simulation, existing web pages may generate new ones as follows: First, each web page is equipped with a topic concerning its contents. Second, links between web pages are established according to common topics. Next, new web pages may be randomly generated and subsequently they might be equipped with a topic and be assigned to web sites. By repeated iterations of these rules, our simulation appears to exhibit the observed structure of the World-Wide Web and, in particular, a power law type of growth. In order to visualise the network of web pages, we have followed N. Gilbert's (1997) methodology of scientometric simulation, assuming that web pages can be represented by points in the plane. Furthermore, the simulated graph is found to possess the property of small worlds, as it is the case with a large number of other complex networks.

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A Note on Stone's Conjecture of Blind Signal Separation

Neural Computation ◽

10.1162/0899766053011492 ◽

2005 ◽

Vol 17 (2) ◽

pp. 321-330 ◽

Cited By ~ 55

Author(s):

Shengli Xie ◽

Zhaoshui He ◽

Yuli Fu

Keyword(s):

Blind Source Separation ◽

Source Separation ◽

Signal Separation ◽

Blind Signal Separation ◽

The Novel ◽

Blind Signal ◽

Simple Simulation ◽

Novel Approaches

Stone's method is one of the novel approaches to the blind source separation (BSS) problem and is based on Stone's conjecture. However, this conjecture has not been proved. We present a simple simulation to demonstrate that Stone's conjecture is incorrect. We then modify Stone's conjecture and prove this modified conjecture as a theorem, which can be used a basis for BSS algorithms.

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Differential Equation Based Adaptive Distance Relaying Setting Method for Series Compensated Line

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1044-1045.482 ◽

2014 ◽

Vol 1044-1045 ◽

pp. 482-485

Author(s):

Jin Hu Zhang ◽

Zhen Yu Xu ◽

Zhi Peng Su

Keyword(s):

Differential Equation ◽

Transmission Lines ◽

Distance Relay ◽

Iterative Calculation ◽

Simple Simulation ◽

Simulation Results ◽

Distance Relays ◽

Distance Relaying

The distance relays of transmission lines find limitations in the presence of series compensated capacitor. One of them is the distance relay setting issue, in which either over-reach problem or under-reach problem may occur. To deal with this issue, a differential equation based adaptive distance relaying setting method for series compensated line is proposed. As for it do not need to identify whether SC/MOV is in fault loop, not need to know the parameters and the operating states of SC/MOV/GAP, and furthermore, it can be realized without the iterative calculation, it is very suitable to be used for the distance relaying adaptive setting of series compensated line. Simple simulation results certificate the proposed adaptive setting method.

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