Communications of the ACM
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How the “Frontier” Became the Slogan of Uncontrolled AI
Artificial intelligence (AI) has been billed as the next frontier of humanity: the newly available expanse whose exploration …
From Daniel Lemire's Blog
Science and Technology links (November 18th 2018)
It seems that reducing your carbohydrate (sugar) intake might be a good way to lose weight: lowering dietary carbohydrate increased energy expenditure during weight...
From Daniel Lemire's Blog
Simple table size estimates and 128-bit numbers (Java Edition)
Suppose that you are given a table. You know the number of rows, as well as how many distinct value each column has. For example, you know that there are two genders...
From Daniel Lemire's Blog
Memory-level parallelism: Intel Skylake versus Apple A12/A12X
Modern processors execute instructions in parallel in many different ways: multi-core parallelism is just one of them. In particular, processor cores can have several...
From Daniel Lemire's Blog
Science and Technology links (November 10th, 2018)
It already takes more energy to operate Bitcoin than to mine actual gold. Cryptocurrencies are responsible for millions of tons of CO2 emissions. (Source: Nature)...
From Daniel Lemire's Blog
Measuring the memory-level parallelism of a system using a small C++ program?
Our processors can issue several memory requests at the same time. In a multicore processor, each core has an upper limit on the number of outstanding memory requests...
From Daniel Lemire's Blog
Science and Technology links (November 3rd, 2018)
Bitcoin, the cryptocurrency, could greatly accelerate climate change, should it succeed beyond its current speculative state. Crows can solve novel problems very...
From Daniel Lemire's Blog
Science and Technology links (October 28th, 2018)
If you take kids born in the 1980s, who do you think did better, the rich kids or the poor kids? The answer might surprise you: The children from the poorest families...
From Daniel Lemire's Blog
Is WebAssembly faster than JavaScript?
Most programs running on web sites are written in JavaScript. There are still a few Java applets and other plugins hanging around, but they are considered obsolete...
From Daniel Lemire's Blog
Science and Technology links (October 20th, 2018)
Should we stop eating meat to combat climate change? Maybe not. White and Hall worked out what happened if the US stopped using farm animals: The modeled system...
From Daniel Lemire's Blog
Validating UTF-8 bytes using only 0.45 cycles per byte (AVX edition)
When receiving bytes from the network, we often assume that they are unicode strings, encoded using something called UTF-8. Sadly, not all streams of bytes areContinue...
From Daniel Lemire's Blog
Validating UTF-8 bytes (Java edition)
Strings are just made of bytes. We send and receive bytes over the network all the time. If you know that the bytes you are receiving form a string, then chances...
From Daniel Lemire's Blog
Nobel-prize winner Rommer on innovation and higher education
Rommer was one of the the winners of the Nobel prize in economics this year (2018). He wrote about higher education and innovation. One of his proposals is theContinue...
From Daniel Lemire's Blog
Science and Technology links (October 13th, 2018)
Chronic exposure to canola oil results in a significant increase in body weight and impairments in working memory… in mice. (Source: Nature) Belly fat is not just...
From Daniel Lemire's Blog
Smart bracelet: my experience with the Mi Band 3
I was an early adopter of fitness bracelets with heart-rate monitoring. I use them to track my heart rate at rest. You heart rate should be around 65 if you are...
From Daniel Lemire's Blog
Science and Technology links (October 6th, 2018)
Ibuprofen extends lifespan in many species including, maybe, human beings. Donna Strickland is the third women to win a Nobel prize in Physics. It appears thatContinue...
From Daniel Lemire's Blog
Quickly parsing eight digits
In my previous post, I described how we can quickly determine whether eight characters are made of digits (e.g., ‘13223244’). It takes a bit over 2 cycles. Suppose...
From Daniel Lemire's Blog
Quickly identifying a sequence of digits in a string of characters
Suppose that you want to quickly determine a sequence of eight characters are made of digits (e.g., ‘9434324134’). How fast can you go? In software, charactersContinue...
From Daniel Lemire's Blog
Science and Technology links (September 30th, 2018)
Oculus is launching a new standalone virtual-reality headset next year, the Oculus Quest. It is the price of a console like the Nintendo Switch, and might haveContinue...
From Daniel Lemire's Blog
Science and Technology links (September 22nd, 2018)
Apple benefits from the chip-making technology of a company called TSMC. This company has surpassed Intel in transistor density. Thus, in some sense, the microprocessors...
From Daniel Lemire's Blog