Month: August 2017

Hurrying feet in crowded camps

Five years ago I wrote about the potential ‘Population Crunch‘ [September 15th, 2012] that could lead to a large increase in the size and number of cities – perhaps upto 1500 new cities emerging over the next few decades as the global population rises from 7.6 billion to 9.8 billion by 2050 [see UN revised report, 2017].  It is a significant challenge to provide an acceptable quality of life to the citizens of these new cities as well as existing ones.  People have been concerned about the density of population in cities and its impact on individuals for more than a century.  In 1910, W.H. Hudson in ‘A Shepherd’s Life’ [Penguin Books, 1910] wrote, somewhat tongue-in-cheek, about London: ‘Some over-populated planet in our system discovered a way to relieve itself by discharging its superfluous millions on our globe – a pale people with hurrying feet and eager, restless minds, who live apart in monstrous, crowded camps, like wood ants that go not out to forage for themselves’  Nothing seems to have changed!

Blinded by the light

It has become a habit during our summer vacation to read the novels short-listed for Bailey’s Women’s Prize for Fiction.  Unusually this year, we were not only unanimous in our choice of the best novel but we also agreed with the judges and selected the ‘The Power‘ by Naomi Alderman.  In another of the books, Do Not Say We Have Nothing by Madeleine Thien, a Chinese composer called Sparrow thinks ‘about the quality of sunshine, that is, how daylight wipes away the stars and planets, making them invisible to human eyes, might daylight be a form of blindness? Could it be that sound was also be a form of deafness? If so, what was silence?’.  I felt some resonance between these thoughts and John Hull’s writings on blindness and my earlier blog posting on ‘Listening with your eyes shut‘ [on May 31st, 2017].  In our everyday life, we are bombarded with sounds from people living around us, from traffic and from devices in our homes and places of work.  We rarely experience silence; however, when we do, perhaps on holiday staying in a remote rural location, then a whole new set of sounds becomes apparent: waves breaking on the shore in the distance, the field mouse rooting around under the floorboards, or the noises of cattle enjoying the lush grass in the field next door.  Okay, so you have to be in the right place to hear these sounds of nature but you also need silence otherwise you are deaf to them, as Sparrow suggests.

The same is true for knowledge and understanding because our minds have finite capacity [see my post entitled ‘Silence is golden‘ on January 14th, 2014].  When you are bombarded with information and data it is easy to become overwhelmed and unable to structure the information in way that makes it useful or meaningful.  In our connected society, information has become like white noise, or daylight obscuring the stars and planets.  Information is blinding us to knowledge and understanding.  We need to aggressively filter the information flow in order to gain insight and knowledge.  We should switch off the digital devices, which bombard us with information constantly, to leave our minds free for conceptual and creative thinking because that’s one of the few tasks in which we can outperform the smartest machine [see my post entitled ‘Smart machines‘ on February 26th, 2014].

In a similar vein see: ‘Ideas from a balanced mind‘ on August 24th, 2016 and ‘Thinking out-of-the-skull‘ on March 18th, 2015.

Less uncertain predictions

Ultrasound time-of-flight C-scan of the delaminations formed by a 12J impact on a crossply laminate (top) and the corresponding surface strain field (bottom).

Here is a challenge for you: overall this blog has a readability index of 8.6 using the Flesch Kincaid Grades, which means it should be easily understood by 14-15 year olds.  However, my editor didn’t understand the first draft of the post below and so I have revised it; but it still scores 15 using Flesch Kincaid!  So, it might require the formation of some larger scale neuronal assemblies in your brain [see my post entitled ‘Digital Hive Mind‘ on November 30th, 2016].

I wrote a couple of weeks ago about guessing the weight of a reader.  I used some national statistics and suggested how they could be updated using real data about readers’ weights with the help of Bayesian statistics [see my post entitled ‘Uncertainty about Bayesian statistics’ on July 5th, 2017].  It was an attempt to shed light on the topic of Bayesian statistics, which tends to be obscure or unknown.  I was stimulated by our own research using Bayesian statistics to predict the likelihood of failure in damaged components manufactured using composite material, such as carbon-fibre laminates used in the aerospace industry.  We are interested in the maximum load that can be carried by a carbon-fibre laminate after it has sustained some impact damage, such as might occur to an aircraft wing-skin that is hit by debris from the runway during take-off, which was the cause of the Concorde crash in Paris on July 25th, 2000.  The maximum safe load of the carbon-fibre laminate varies with the energy of the impact, as well as with the discrepancies introduced during its manufacture.  These multiple variables make our analysis more involved than I described for readers’ weights.  However, we have shown that the remaining strength of a damage laminate can be more reliably predicted from measurements of the change in the strain pattern around the damage than from direct measurements of the damage for instance, using ultrasound.

This might seem to be a counter-intuitive result.  However, it occurs because the failure of the laminate is driven by the energy available to create new surfaces as it fractures [see my blog on Griffith fracture on April 26th, 2017], and the strain pattern provides more information about the energy distribution than does the extent of the existing damage.  Why is this important – well, it offers a potentially more reliable approach to inspecting aircraft that could reduce operating costs and increase safety.

If you have stayed with me to the end, then well done!  If you want to read more, then see: Christian WJR, Patterson EA & DiazDelaO FA, Robust empirical predictions of residual performance of damaged composites with quantified uncertainties, J. Nondestruct. Eval. 36:36, 2017 (doi: 10.1007/s10921-017-0416-6).