# The Azimuth Project Blog articles in progress (Rev #117, changes)

Showing changes from revision #116 to #117: Added | Removed | Changed

There are usually several blog articles in various states of progress that need feedback and are being actively discussed in the forum before being posted to the blog. You can find them here. For an index of all blog articles that have been published, see Azimuth blog overview.

If you want to write a blog article on this wiki, go ahead! But there are some stylistic and formatting issues you need to think about. So, please start by reading How to Write a Blog Entry.

# Frederik De Roo

## Background profiles in the atmosphere

• Main author: Frederik De Roo

• Status: planned, but doesn’t exist yet.

• Summary: some background material necessary for the log forcing, but independent so better separately.

# Curtis Faith

## Making decisions under uncertainty

Summary: Groups often want to make the right decisions. So they spend a lot of time in the decision process itself. A better approach is to acknowledge when perfect decisions don’t exist and to incorporate the uncertainty itself into your plans.

# Alastair Jamieson-Lane

## Stochastic cross-impact balance analysis

• Forum discussion group: Blog - stochastic cross-impact balance analysis

• Summary: An introduction to cross-impact balance analysis and the new stochastic version, which are techniques for constructing self-consistent scenarios of complex situations.

# Matteo Smerlak

## The mathematical origin of irreversibility

• Main author: Matteo Smerlak.

• Status: published

• Summary: An introduction to the mathematical origin of irreversibility in nonequilibrium thermodynamics, including results such as the detailed fluctuation theorem and the integral fluctuation theorem.

# Blake Stacey

## Invasion fitness in moment-closure treatments

• Main author: Blake Stacey

• Forum discussion group: Invasion fitness in moment-closure treatments

• Status: work in progress.

• Summary: Moment closures are a way of forgetting information about a system in a controlled fashion, in the hope that an incomplete, fairly heavily “coarse-grained” picture of the system will still be useful in figuring out what will happen to it. Sometimes, this is a justifiable hope, but in other cases, we are right to wonder whether all the algebra it generates actually leads us to any insights. Here, we’ll be concerned with a particular application of this technology: studying the vulnerability of an ecosystem to invasion. We shall find expressions for invasion fitness, the expected relative growth rate of an initially-rare species or variety.

# David Tanzer

## Petri net programming (part 2) – Introduction to stochastic Petri nets

• Main author: David Tanzer

• Wiki page: Blog - Petri net programming (part 2)

• Forum discussion group: Blog - Petri net programming (part 2)

• Status: published.

• Summary: Introduces the concept of stochastic Petri nets. Starts with a general discussion of reaction network dynamics, followed by an exposition of the mass action kinetics (and its limitations). This is followed by an exploration of the continuous deterministic limit of the stochastic model. Finally, I calculate equilibrium solutions for simple reaction networks.

# David Tweed

## Worried about the environment? You’re seeing things!

• Main author: David Tweed

• Status: text, a few supporting links.

• Summary: Thoughts about the disproportionate impact of pictures on human psychology.

# Tim van Beek

## Your model is verified, but not valid! Huh?

• Main author: Tim van Beek

• Forum discussion group: Blog - your model is verified, but not valid! Huh?

• Status: published.

• Summary: Critics of climate science in general, and sceptics of the statement that anthropogenic (man-made) global warming is real, often claim that climate models are wrong and cannot be trusted. But what does “wrong” mean here and what can and should be done to make models more trustworthy, from a software engineering viewpoint? In a first step, we’ll introduce some relevant technobabble.

## A quantum of warmth

• Main author: Tim van Beek

• Wiki page: Blog - a quantum of warmth

• Status: published.

• Forum discussion group: Blog - a quantum of warmth

• Summary: A closer look at the heat balance of the Earth and its atmosphere. An explanation of downward longwave radiation (DLR), generated by the atmosphere of the earth and why it does not violate the second law of thermodynamics.

## Fluid flows and infinite dimensional manifolds (part 1)

• Main author: Tim van Beek

• Forum discussion group: Blog - Fluid flows and infinite dimensional manifolds (part 1)

• Status: published.

• Summary: Fluid flows can be modelled by one parameter subgroups of diffeomorphism groups. How diffeomorphism groups can be seen as infinite dimensional Riemannian manifolds, and how certain nonlinear partial differential arise as geodesic equations.

## Good vibrations

• Main author: Tim van Beek

• Wiki page: Blog - good vibrations

• Forum discussion group: Blog - good vibrations

• Status: stub.

• Summary: Recapitulation of previous blog posts and short tour to molecular quantum mechanics necessary to understand that radiation equations of the atmosphere of the earth.

## The color of night

• Main author: Tim van Beek

• Wiki page: Blog - the color of night

• Forum discussion group: Blog - The color of night

• Status: partially done.

• Summary: How big is the effect of downward longwave radiation (DLR) really? What do measurements say? What instruments are used? Are there alternative explanations of the 33 Kelvin gap of the zero dimensional energy balance model?

## Increasing the signal-to-noise ratio with more noise

• Main author: Tim van Beek and Glyn Adgie.

• Status: published

• Summary: An introduction to stochastic resonance.

# Ken Webb

## Connections: Petri nets, systems biology, and beyond

• Main author: Ken Webb

• Wiki page (series outline): Connections: Petri nets, systems biology, and beyond

• Forum discussion group: Connections: Petri nets, systems biology, and beyond

• Status: work in progress.

• Summary: A brief but systematic exploration of various types of networks, and how they’re really all the same. Starting with a simple reaction network and corresponding Petri net, I demonstrate how to transform these into systems biology networks, systems of differential equations, Unified Modeling Language (UML) diagrams, mind maps, agent based models, and more. Along the way I introduce third-party tools that are able to process each of the resulting formats. This first part restricts itself to the transformation to differential equations.

# Other

## Mathematics of the Environment (part 3)

• Main author: John Baez

• Forum discussion group: [Blog - mathematics of the environment (part 3)]](http://forum.azimuthproject.org/discussion/1130/blog-mathematics-of-the-environment-part-3/)

• Status: published.

• Summary: a discussion of the greenhouse effect, including the Schwarzschild equation and Beer-Lambert law.

# Contributions to external blogs

## Prospects for a green mathematics

category: blog, meta