Mild science news; maps; stories; occasional finance, economics, and geopolitics; reviews; humor

21 May 2018

Credibility and the Internet: Queuing Theory

This was old news about queues back in the 1990s, yet it was written up as an (Inderscience) journal article, and received coverage as though a new finding in the June 2010 issue of ScienceDaily, an online "new discoveries!" update service owned by Reuters. See footnote #1 for even more.

M/M/1 queues, Kendall notation, and models of balking and reneging behavior are certainly useful. However, the concepts and most models have been well-established for at least forty years.

This Wiley text book, Fundamentals of Queueing Theory, was published in 1998.



An earlier edition was published in 1983, and explains in detail the theory and application of the concepts presented in the journal article summarized by ScienceDaily in 2010.

A little more about M/G/1

Over at Math StackExchange, I noticed a rare inquiry. If you're curious to learn more about queues, go read my answer to this question, Kendall notation's “General distribution”, what does that mean?

I found this comment endearing:

Oh I thought that this stuff wasn't even used in real life jobs... I thought it was merely theoretical, but seems that I'm wrong!
I'm okay with the G general theory [G as the general case when you just don't know what sort of service time distribution to expect] since I'm not required to study it for now (I'm following an academic course), I just wanted to understand what the G meant and you helped me in that. Do you have any experience with multi-class queues too?

Reference
  1. Liao et al. "Optimal staffing policy for queueing systems with cyclic demands." International Journal of Services and Operations Management, 2010; 7: 317-332.

20 May 2018

Chemical Heritage

This aluminum necklace was on display at the Chemical Heritage Foundation (CHF) in 2010. It was part of the CHF's Chemistry and Fashion: Making Modernity exhibit. A description of the necklace is still available via an unfortunately image-free post about Atomic Age women's jewelry

I like the necklace, a lot! Aluminum is very light; I do wonder whether the same necklace could be made of platinum or possibly iridium. If so, how it would it compare--in appearance (e.g. lustre) and weight-- to the aluminum version?


Ladies necklace made of grey metal nested wedges
Aluminum necklace circa 1950

I wrote this post in October 2010. Times changed at the Chemical Heritage Museum since then, resulting in many broken links. This is an expanded version of that post, with replacement by valid alternative links for inline URLs. I apologize if I missed any. 

URL persistence hasn't been taken as seriously as the IETF and Internet Society had hoped; URL status, according to a Google Groups thread, as of 2013:

URLs are simply not persistent...from a recent study, about 15% of URLs from a large sample reach a lifetime of 1000 days. It's abysmal. And other studies back it up.

No Moore Chemical Heritage

Sadly, Chemical Heritage was absorbed by the Science History Institute in 2018, including the CHF's 5-story building. Most CHF collections can still be viewed at the museum's original location, at 315 Chestnut Street in Philadelphia, Pennsylvania. I was born in Philadelphia, and attended graduate school there, so I feel an affinity. 

The former CHF building is near Centennial Hall, the Liberty Bell, and adjacent to a nice residential neighborhood called Society Hill. Penn's Landing is a few blocks to the east. That's where William Penn first arrived on the shores of America. 

Gordon E. Moore helped found the Chemical Heritage Foundation, and his generous donations provided much of the initial and sustaining funds.

Moore's Law


magazine cover
Periodic Tabloid: 
Musings on the Molecular

Interested in the legacy of Gordon Moore? A reproduction of his 1966 article, in which he introduced his famous law, is included in Understanding Moore's Law: Four Decades of Innovation. The book also recounts many observations by Moore, his peers, competitors, and others. It was written in order to commemorate the 40th anniversary of Moore's Law. 

Although "Understanding Moore's Law" was published by the now defunct CHF Press, the Science History Institute kindly keeps an electronic version of the full text available as a PDF for online readers.

Heritage of Chemistry: Moore notable, noble chemists

I promise that this heading will be my final pun for today. It is a double pun, the best kind!

When I first wrote this, chemist and materials scientist Andre Geim had recently won the Nobel Prize.  In merely 10 years, he went from the dubious distinction of receiving an IgNoble prize for levitating frogs with magnets to winning the Nobel Prize for producing a one atom-thick material consisting of carbon atoms, arranged in a hexagonal lattice.  Geim named it graphene, and mapped its properties: incredibly thin but still incredibly strong, good heat and electrical conductivity, almost entirely transparent yet very dense.