Battery Learning Curves

A few months ago, I spent some time on trying to predict the changes in batteries over time. My aim was to estimate when electric cars would finally be as cheap or cheaper than internal combustion engine cars. However, my approach in that blog post was extremely naive since I didn't know about learning curves. Simply put, learning curves are a real world phenomenon where a good or service becomes consistently cheaper over time. As shown in the learning curve link, solar modules have gotten 99.6% cheaper since 1976. From $100 to about $0.3, that's almost 4 orders of magnitude!

2024-05-29

Summary of Same as Ever by Morgan Housel

One of my favorite books this year has been Same as Ever: A Guide to What Never Changes by Morgan Housel. I've read some of his blog posts at Collab Fund before, so I already knew the book would be good. His writing style is simple on the surface, but at the same time surprisingly insightful. (Which is quite a feat, I wouldn't disagree if you say my academic writing has been the opposite.) Morgan also often comes up with new ideas that I've never heard before. For example, he has argued that the German army in the 1930s got so strong because they had their weapons taken away from them by the Treaty of Versailles. Thanks to the lack of old weapons, they built new and more advanced equipment from scratch.

2024-04-29

Some SaaS banned me, again

A few years ago, a good friend of mine happily moved to Microsoft Office 365. It was great, he said, because his files were synced across all his devices and he felt it was making him more productive. He even stored many gigabytes of personal pictures on OneDrive because the storage pricing was fair and it was easy to do. Then, he shared his picture collection with one person and got banned almost immediately. No OneDrive, no Word, no opportunity for backup, no nothing. Contacting customer support didn't help. If I remember correctly, Microsoft claimed he was possibly involved in terrorist activities. In truth, Microsoft probably had a problem with sharing pictures of children. But, he shared the pictures with his own wife. He shared pictures of his children with his wife. The Dutch tech site Tweakers wrote a long article about similar events with software as a service (SaaS) platforms in 2021, so this was not an one-off occurrence.

2024-04-25

The history of the ROC curve

The Receiver Operating Characteristic (ROC) curve is a well-known tool used to evaluate the performance of binary classifiers. Its history is clear. According to Wikipedia, it

"was first developed by electrical engineers and radar engineers during World War II for detecting enemy objects in battlefields, starting in 1941, which led to its name ('receiver operating characteristic')"

Another source also states that the ROC curve was first used during the second world war to distinguish between enemy targets, or just noise by radar receiver operators (utah.edu, 2007).

2024-04-17

Updating my notes via email

Charles Darwin made it a habit to immediately write down anything that conflicted with his own ideas, so his brain would not forget or ignore it. In his own words:

"I had also, during many years, followed a golden rule, namely that whenever published fact, a new observation of thought came across me, which was opposed to my general results, to make a memorandum of it without fail and at once; for I had found by experience that such facts and thoughts were far more apt to escape from the memory than favourable ones."

Based on this, I've also made it a habit to quickly write down new ideas or thoughts. Unlike Darwin, however, I don't carry a notebook with me. Instead, I prefer to store my notes in a Git repository. Unlike a notebook, a Git repository is more fireproof, can more easily be searched and edited, and can scale to much larger sizes. Jeff Huang, for example, wrote that he has a single text file with all his notes from 2008 to 2022. At the time of his writing, the file contained 51,690 handwritten lines of text. He wrote that the file been his "secret weapon".

2024-03-08

Installing Forgejo with a separate runner

On the 15th of February 2024, Forgejo announced that they will be decoupling (hard forking) their project further from Gitea. I think this is great since Forgejo is the only European Git forge that I know of, and a hard fork means that the project can now grow more independently. With Forgejo, it is now possible to easily self-host host a forge. This is great because it allows decoupling it from American Big Tech.

This post will go through a full step by step guide on how to set things up. This guide is based on my Gitea configuration that I ran for a year, so it works. During the year, I paid about 10 euros per month for two Hetzner servers. The two servers allow separating Forgejo from the runners. This ensures that a heavy job on the runner will not slow down the Forgejo server.

2024-02-19

How much have batteries changed over time?

From time to time, batteries make the headlines because they store too little energy, because they are too expensive, or because the costs have dropped dramatically in the last year. These things could indeed be true at the same time. Or, as Hans Rosling would say, "things can be bad, and getting better." I was curious by how much. To figure out where things are heading, let's not focus on headlines and instead look at data for multiple years.

Phone Batteries

As a first investigation, I wonder whether much is happening in the area of small batteries. Thanks to the rise of smartphones, these batteries may have improved dramatically over time. We could checkout the raw battery prices, but consumers would not buy at these prices. So instead let's look at consumer smartphone prices. Smartphones are a mass produced product, so they should be able to incorporate state-of-the-art battery technology. Let's therefore look at iPhone battery capacity over time.

2024-02-03

Encrypting and decrypting a secret with wasm_bindgen

Doing a round trip of encrypting and decrypting a secret should be pretty easy, right? Well, it turned out to be a bit more involved than I thought. But, in the end it worked here is the code for anyone who wants to do the same.

I'll be going through the functions step by step first. The full example with imports is shown at the end.

First, we need to generate a key. Here, I've set extractable to false. This aims to prevent the key from being read by other scripts.

fn crypto() -> web_sys::Crypto {
    let window = web_sys::window().expect("no global `window` exists");
    window.crypto().expect("no global `crypto` exists")
}

pub fn generate_key() -> Promise {
    let sc = crypto().subtle();
    // Symmetric encryption is used, so the same key is used for both operations.
    // GCM has good performance and security according to Wikipedia.
    let algo = AesKeyGenParams::new("AES-GCM", 256);
    let extractable = false;
    let usages = js_array(&["encrypt", "decrypt"]);
    sc.generate_key_with_object(
        &algo,
        extractable,
        &usages
    ).expect("failed to generate key")
}

2024-01-28

An old solution to modern OpenAI GPTs problems

Ever since the introduction of ChatGPT, OpenAI has had a compute shortage. This might explain their current focus on GPTs, formerly known as Plugins. Simply put, you can see GPTs as a way to wrap around the base language model. In a wrapping, you can give some instructions (a prompt), 20 files, and enable Web Browsing, DALL·E Image Generation, and/or Code Interpreter. Also, you can define an Action, which allows the GPT to call an API from your own server.

At first sight the possibilities seem limited for developers. The code interpreter will only run Python code inside their sandbox. Furthermore, the interpreter has no internet access, so installing extra tools is not possible. You could spin up your own server and interact via the Actions (API calls), but that has some latency and requires setting up a server. Without spinning up a server, you could define some CLI script in Python and write in the instruction how to interact with that Python script. Unfortunately, this does limit the capabilities. Not all Python packages are installed in the sandbox and there is only so much that can be expressed in the instruction.

2023-11-25

Triggering `entr`

entr is an extremely useful little tool that can watch files and run a command automatically upon a file change. So, for example, the following can be used to watch all Rust source files and run the tests:

ls src/**/*.rs | entr -s "cargo test"

This works great and I've been using it for years. However, recently I switched to a Mac which restricts the number of files that can be watched to 256. This is a problem for large codebases. Furthermore, it can sometimes be very difficult to figure out which files to watch exactly. For instance when watching LaTeX files, it is important to not watch the log files or entr would go into an infinite loop.

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