on modeling infection

Compartmental models are often used to simplify the mathematical modeling of infectious disease. The population is split into compartments and it is assumed each individual in a compartment has the same characteristics. While this may appear to be rather crude, such models have shown to accurately model previous infectious outbreaks[1]....

signals from magnetic medium

Recently we had an interesting problem posed to us. The more general problem is detecting magnetization on a granular medium. Such questions are relevant for magnetic recording, e.g. tape, hard disk drives, etc....

Runge-Kutta in Swift

Apple’s Scene Kit has a built in physics engine. However, we discovered it wasn’t accurate for particular cases. We decided to replace the physics engine with a Runge-Kutta method. ...

light-weight way to capture results from cloud HPC/HTC

For large HTC (or HPC) computations on the cloud, ‘spot instances’ (AWS-speak), ‘low-priority VM’ (Azure-speak) or ‘preemptible VM instances’ (GoogleCloud-speak) are the low cost options for compute. Of course, the challenge here is that these instances/VM can vanish at anytime. If you’re doing a large HTC task, you want to make sure you save your result (and/or checkpoint) files as soon as they are generated to persistent storage. Otherwise you lost the computation you just paid for....

persistent storage

On-premise computing cluster usually have RAID for persistent storage and a robust backup solution. Storage in the cloud costs $. ...

macOS automation

In a vain attempt* to get Desktop Icon Manager (DIM) into the Mac App Store, we wrote a class that simply ‘hides’ or ‘reveals’ the Desktop icons with a notification. Quite useful when giving presentations (alas, our Desktops are usually ‘messy’ with current work)....