models
gregladen | April 29, 2015I recently posted an overview of a new climate study, Comparing the model-simulated global warming signal to observations using empirical estimates of unforced noise, by Patrick T. Brown, Wenhong Li, Eugene C. Cordero & Steven A. Mauget. That study is potentially important because of what it says about how to interpret the available data on global warming caused by human generated greenhouse gas pollution. Also, the since publication the study has been rather abused by climate contrarians who chose to interpret it very inaccurately. This is addressed in this item by Media Matters.
My…
rallain | June 24, 2010I was having a discussion with my father about the budgetpocalypse for universities. I don't know how it came up, but he asked: "What college is the department of Math in?" At Southeastern Louisiana University, the Department of Math is in the College of Science and Technology.
Here is a paraphrase of our conversation.
Me: That is odd. Math isn't a science, and it isn't really a technology. Well, I guess you could argue it is a technology.
Father: What? Math is a science. It is a pure science.
Me: I don't think it is a science. Science is all about models and seeing how they agree with…
stoat | June 18, 2010Via mt I find
too much of our scientific code base lacks solid numerical software engineering foundations. That potential weakness puts the correctness and performance of code at risk when major renovation of the code is required, such as the disruptive effect of multicore nodes, or very large degrees of parallelism on upcoming supercomputers [1]
The only code I knew even vaguely well was HadCM3. It wasn't amateurish, though it was written largely by "software amateurs". In the present state of the world, this is inevitable and bad (I'm sure I've said this before). However, the quote above is…
rallain | May 31, 2010So suppose you saw something that looked like this:
This is a ball shot out of a shooter device. Well, it is a vypthon animation of a ball. What would you do if you came to see this video? If I had not made it, I would say it is an unrealistic video. It does not agree with my basic model of how things move after being thrown or shot or whatever. Interestingly (but unrelated) there was a set of physics questions that showed different possible paths of a thrown ball. The path representing the motion above was a common choice.
Like I said, I made that animation. Here is another one. In…
rallain | January 2, 2010I have been meaning to write about this for quite some time. Really, I wanted to reply to Chad's article on science at Uncertain Principles, but you know how things go. So, here are my key and interesting points about science in random order.
Science is all about models (not ball bearings)
Science is about making models. What is a model? A model can be lots of things. It can be a mathematical relationship, a conceptual model, or even a physical model. One model I like to use is static friction. For many cases, the frictional force can be modeled as:
This model says the frictional…
rallain | December 10, 2009This picture has been all over the blogs.
I don't want to talk about this picture too much - that has been done (a good summary discussion can be found at Bad Astronomy). Apparently, this is some type of rocket mistake or something.
Although the picture is cool, it is not as cool as this simulation that someone made.
Here is the best shot from the video:
Maybe that picture didn't turn out so well. The point is that someone made a simulation (I assume it is a simulation, and not just an animation). How do you know if a simulation is any good? You look and see how well it compares with…
revere | November 14, 2009We've talked aplenty about how much we still need to understand about influenza. Not just its basic biology but its dynamics. How does it spread over space and time and how existing infection rates affect future infection rates and how each are related to the number of susceptibles in the population. It's even more than that. There are other viruses perhaps competing for or perhaps cooperating with the flu virus in its sole job, to make copies of itself, using the host's (i.e., our own) biological machinery. You can imagine a scenario whereby once a lot of cells are infected by one virus,…
revere | August 6, 2009Making predictions about something as unpredictable as flu is foolhardy. I rarely (if ever) do it, but I'm going to do it now. I am predicting a bad and early H1N1 swine flu season in the northern hemisphere next fall and winter. The reasons for this departure from our usual custom is a paper in Nature from 2007 I just re-read. It's entitled "Seasonal dynamics of recurrent epidemics" by Stone, Olinkyl and Huppert from Tel Aviv University and it appeared in vol. 446, pp 533-536, 2007 (doi:10.1038/nature05638; html version here, if you have a subscription). The paper isn't specifically about…
revere | May 15, 2009It is clear that if you want to get a so-so paper published in a top tier journal, the best way to do it is to write about a breaking medical news event and get there first. We saw this with avian influenza and SARS and now it's being repeated with swine flu. The Scientist had a story yesterday about how The New England Journal of Medicine (NEJM) and Science, two of the highest profile science journals in the world, pushed through some swine flu papers at record speed last week:
An international research team led by Neil Ferguson of Imperial College London published a report online today (May…
revere | May 12, 2009Trying to figure out where the incipient swine flu pandemic is heading and how fast it is heading there is shooting at a moving target, and this one is moving pretty fast. The best we can do at this point is use whatever information we have to make some educated guesses about different scenarios along with how likely various scenarios are. We used to do this on the back of an envelope, Now we use computer programs. I'm not sure we are doing much better (or much worse), but we can make use of more information and the answer looks prettier when displayed.
Expedited publication of such an…
rallain | May 6, 2009I probably should have included this idea on my "All about science" blog post. Maybe I didn't put it in there because if I talk about what science is you can figure out what it is not.
Science is not math
Science is all about making models. It is true that many current models are mathematical models, but it doesn't have to be that way, and it hasn't always been that way. Think about rubbing a piece of metal with a magnet. It gets magnetized - right? What if you then cut that magnet in half? Then you have two smaller magnets. How can you make a model that explains this phenomena? Yes…
rallain | April 16, 2009I have been meaning to write about this for quite some time. Really, I wanted to reply to Chad's article on science at Uncertain Principles, but you know how things go. So, here are my key and interesting points about science in random order.
Science is all about models (not ball bearings)
Science is about making models. What is a model? A model can be lots of things. It can be a mathematical relationship, a conceptual model, or even a physical model. One model I like to use is static friction. For many cases, the frictional force can be modeled as:
This model says the frictional…
evolvingthoughts | April 3, 2009There's a famous anecdote about Wittgenstein and his friend Piero Sraffa by Norman Malcolm (Ludwig Wittgenstein: A Memoir):
Wittgenstein was insisting that a proposition and that which it describes must have the same 'logical form', the same 'logical multiplicity', Sraffa made a gesture, familiar to Neapolitans as meaning something like disgust or contempt, of brushing the underneath of his chin with an outward sweep of the finger-tips of one hand. And he asked: 'What is the logical form of that?' Sraffa's example produced in Wittgenstein the feeling that there was an absurdity in the…
evolvingthoughts | March 28, 2009A dozen or so years ago, or maybe more, I was heading up the communications section of The Walter and Eliza Hall Institute of Medical Research in Melbourne, when I employed a young biology graduate as a graphics guy to do medical graphics. This he did for a while, until he started playing with three-dimensional graphics software. He did some animations of cell surface signalling molecules, and of malaria parasites, and cancer cells, and took them to the director, and suggested that we set up an animation unit within the department.
This we did, and within a short while, Drew Berry had managed…
evolvingthoughts | March 19, 2009Ian Musgrave has a brilliant post showing that Dembski's revisiting of the old creationist canard that Dawkins' 1984 Weasel program, designed to show that random variation and selective retention can "evolve" a target phrase, in this case Shakespeare's "Methinks it is a weasel" (oops; I nearly had my own mutation there - I typed "methings"), is a load of old cobbler's. Of course we expect nothing less from Ian*, and nothing better from Dembksi.
* But my title is better than his.
rallain | February 24, 2009Quantum mechanics is not my area of expertise. Really, I have no area of expertise. However, I think it is time to bring the whole photon thing back up. Yes, I know I was a little harsh before. Maybe I should start over.
First, models. Yes models. I think science is all about models. Scientists build models that attempt to agree with observations. These models could be mathematical, physical, conceptual or numerical (like a computer program). For example, take Newton's Law of gravity (which isn't really a law). It says that the gravitational force between two objects has the…
evolvingthoughts | February 21, 2009A 6th grade maths and science teacher emailed me about whether theories could become laws. Below the fold is his request and my reply. The short answer is that when laws grow up, they become theories, not the other way around.
Cameron Peters wrote:
Dr. Wilkins,
I was hoping you might be able to provide some insight on a question that is circulating amongst the NSTA email list serve concerning laws and theories. Specifically, there is some disagreement ( I would say confusion) of the difference between the two and, in particular, why a theory cannot become a law. Also, the question has arisen…
rallain | January 18, 2009Podcasts are great. While cleaning the car today, I listened to a new one - Stuff you missed in history class (itunes link). In one episode, they were talking about alternative theories about early visits to America. There was some guy that was claiming the Chinese visited the new world 70 years before Columbus (or something to that effect).
This is a great example of how similar science and history are to each other.
Both science and history make 'models'. In history this may be 'the Chinese visited americas before the Europeans'. It is just like a model in science. It is an idea that…
revere | January 15, 2009New Scientist reporter Mark Buchanan has a fascinating article this week on "the curse of work." The title might be the least satisfactory thing about this examination of a new mathematical article that attempts to explain the inexplicable:
"Parkinson's law", first published in an article of 1955, states: work expands to fill the time available for its completion. Is it more than just a cynical slogan? (Image: OJO Images/Rex Features)
It is 1944, and there is a war on. In a joint army and air force headquarters somewhere in England, Major Parkinson must oil the administrative wheels of the…
rallain | September 15, 2008I like computers, really I do. Computational physics is a good thing. However, there is a small problem. The problem is that there seems to be a large number of people out there that treat numerical methods and simulations as something different than theoretical calculations. You can tell who these people are because they refer to simulations as "experiments". But what do these simulations really do in science? What is science really all about?
**Science**
To me, science is all about models. Making models, testing models, upgrading models. Models. Some examples are the model of…