The VPM-B model (of which I have described my understanding in previous posts) has a “derivation” in terms of bubble physics which I, as readers should have noticed, have some trouble to follow through completely as it is, to say the least, ad hoc and sketchy in places. I bet, only based on this derivation … Continue reading “VPM-B for real dives (or not)”
One of the features that Subsurface users kept asking for were other deco models besides Bühlmann (including gradient factors). In particular, they wanted to see a bubble model implemented. I was reluctant to do so for some time since I believed (like many other divers) that you can produce fine decompression profiles that look like … Continue reading “VPM-B: How it works (the no non-sense version)”
This is the first technical post about the inner workings of the VPM-B deco model. Here I will just present the algorithm (including the relevant formulas, some of them maybe in an unusual form) while the physical motivation or derivation will be the subject of a future post. I try not to parrot the … Continue reading “VPM-B: How to compute your deco”
Dies ist der erste technische Post darüber, wie VPM-B funktioniert. Ich werde nur den Algorithmus beschrieben (mit allen wichtigen Formeln, einige davon vielleicht in ungewohnter Form), während die physikalische Herleitung in einem späteren Post behandelt werden wird. Ich werde nicht versuchen, die ursprüngliche Herleitung nachzubeten (auch schon alleine, weil ich sie nicht wirklich verstehe), sondern … Continue reading “VPM-B: Wie funktioniert’s (deutsche Übersetzung)”
In a comment, Rick suggested that given that in the end, VPM-B computes depth dependent maximal gradients, one could compare those to the depth dependent gradients computed from the Buehlmann model and expressed as gradient factors (i.e. as percentage of the gradient of a plain vanilla Buehlmann gradient). Here is what I found when I … Continue reading “VPM-B Gradients as Gradient factors”
It has been very quiet here for a while. That is partly because there is a topic that I wanted to discuss here and since my take was going to be at least somewhat problematic, I felt for a while that I needed to do more reading to get the facts right. But now the … Continue reading “Probabilistic decompression models: Probably problematic”
I was thinking what might be a good measure for decompression quality or stress. This also comes as O’Dive with their end user Doppler Device claim to provide exactly that in their mobile phone application. As said before, I have some doubts about their approach, so let’s try to come up with something better. As … Continue reading “A measure for decompression stress”
How good was the deco of my dive? For those of us who strive to improve their diving this is a valid question to find ways to optimise how we get out of the water. In Subsurface, for example, we give various information including the individual tissues’ ceilings as well as the heat-map. Recently, on … Continue reading “Rating decompression”
Recently, I had a look at the SAUL decompression model and I have a couple comments on it. They are at best inspired by what I have read and fall in some independent classes, so I will spread them over a number of posts in the upcoming days. SAUL is a probabilistic model. This means … Continue reading “Establishing safety is hard”
Recently, at Subsurface, we decided to look into the calculations of oxygen toxicity related to diving. Here is what I learned (admittedly, not too much). According to what we could find on the inter-webs, there are two things to consider: The effect on your brain (the CNS value) and on you lungs (OTU for oxygen … Continue reading “A few thoughts on Oxygen Toxicity”
