All posts by EdwardM

Facial recognition’s 96 percent false positive rate

Close enough for government work, eh?

“If we would use the software only [to identify subjects], we would not solve the case 95-97 percent of the time,” Craig said. “That’s if we relied totally on the software, which would be against our current policy … If we were just to use the technology by itself, to identify someone, I would say 96 percent of the time it would misidentify.”

Source: Detroit police chief cops to 96-percent facial recognition error rate | Ars Technica

Not everyone can wear a mask, so let’s publicly humiliate them!

In February or early March, if you wore a mask, you were publicly humiliated and the subject of antagonism on social media – masks were useless when worn by the public said the experts!

Weeks later, wearing a face mask was then encouraged. But if you wore the wrong kind of mask – such as a surgical mask or a non-medical grade N95 used mask you had in your shop, which you bought last year – you were publicly called out for wearing PPE that should be turned over to your local hospital. (Reality check – hospitals threw away donated PPE that had been used or was unsuitable).

Then, they said, use a home made cloth or improvised face mask. If you were not wearing a face mask, you were then publicly humiliated and called out for putting other people at risk, you selfish jerk!

I have seen comments on social media and in newspaper Letters to the Editor, calling out people for wearing bandannas, scarves or other insufficient face covering (which was, in fact, specifically listed as sufficient by the CDC).

Now businesses are banning people with bona fide documented medical reasons for not covering their airway, in violation of the ADA.

No matter what you do regarding face masks, you are  wrong. There is no way to do the right thing – anything and everything you do is  wrong in someone’s view.

Continue reading Not everyone can wear a mask, so let’s publicly humiliate them!

Is the pandemic accelerating?

Dr. Tom Frieden is a former Director of the Centers for Disease Control. Yesterday, he put out this tweet:

Looking at those 1-million increases in ever shorter time frames seems scary. But is it an accelerating curve?

If we graph those points from 1 million to 9 million with the number of days on the X-axis, we end up with a straight line, with the curve fit having an R^2 value of almost 99%. If we squint our eyes a bit, we can see a slightly increasing trend, especially with the final data point. But this is not yet certain enough to proclaim the pandemic is accelerating based on this data.

Consequently, the claim of an accelerating pandemic, based on this data set alone, is questionable as of this specific day. Other data, or newer data, may confirm an acceleration. We just don’t see it in this data set.

Continue reading Is the pandemic accelerating?

TikTok Secretly Spying On iPhone Users?

TikTok app on iPhone has been copying the contents of the “clipboard”. Now that your clipboard is shared across devices, stuff you copied to the clipboard on a Mac can end up on an iPhone and then intercepted by TikTok. TikTok will have to change the feature, moving forward. Whether something similar is done on Android is not known.

Ever copy a password to your clipboard? Well, duh, we all have!

Source: Warning—Apple Suddenly Catches TikTok Secretly Spying On Millions Of iPhone Users

Countries ‘unlikely’ to impose full lockdowns again

Apparently multi-month lock downs did not work and were not the right away to address the pandemic? That seems to be what they are saying.

Countries are very unlikely to impose another full lockdown even as virus cases appear to be resurging in some parts of the world, analysts told CNBC.

Source: Countries ‘unlikely’ to impose full lockdowns if there’s second wave, analysts say

In many U.S. states the outbreak is now much worse than it was in March and April when lock downs were imposed. Now that it is worse, lock downs are no longer being considered. What explains this?

Continue reading Countries ‘unlikely’ to impose full lockdowns again

Why are people wearing face masks with unfiltered outflow valves?

The Oregonian has been running a “fake news” ad on their main front page for weeks for a vendor of face masks. Here’s the ad, with their defective component highlighted:

The product they are marketing contains an outlet valve. Which defeats the entire purpose of the use of the face mask – to prevent outflow from those who have asymptomatic Covid-19. Indeed, some jurisdictions prohibit the use of these masks as the entire purpose of face masks is to prevent outflow of Covid-19 from asymptomatic individuals.

Continue reading Why are people wearing face masks with unfiltered outflow valves?

The “hovercover” – very interesting concept

Throughout the week commencing June 8th, Griffon Hoverwork & Stuart Canvas Group successfully delivered and installed…

Posted by Griffon Hoverwork on Tuesday, 23 June 2020

Interesting concept, using hovercraft-like technology to create a “floating” covered area on a sensitive surface. See the above for more information.

I am a hovercraft enthusiast. I just finished re-coating the surface of my 14 foot hovercraft from its original blue color to Piper Cub Yellow. This is a homemade hovercraft, covered in aircraft fabric on the top surface, and powered by a 16 hp lawn mower engine. Top speed is about 25 mph. Total weight is about 300 pounds and can carry 2 adults (3 adults if not too big and you are patient about getting up on the air bubble).

The original blue covering was peeling and cracking. That was painstakingly removed from the old fabric over a period of weeks. The fabric was repaired (several torn sections had to be fixed), cleaned, vacuumed, re-shrunk (heat shrinkable fabric), and then coated with an adhesive layer, then 3 coats of a “filler” layer and ultraviolet light protectant, and then five coats of Piper Cub Yellow. I used the Stewart Systems water-based coating system, rather than the traditional nitrate dope and butyrate dope method. Really liked using the Stewart Systems products, their tech support was very helpful, their online downloadable e-book is excellent – and I would recommend their products for similar fabric coverings.

When operated with 2 people, the hovercraft exerts a force of perhaps 7 to 9 pounds per square foot – vastly less than a person standing on their feet! A 200 pound person is putting 200 pounds on the ground – over may be 1/2 square foot of surface, by comparison!

Good news on coronavirus in the U.S. as of June 23, 2020?

Some good news, right?

Source: United States Coronavirus: 2,424,168 Cases and 123,473 Deaths – Worldometer

Deaths are often counted on the day they are recorded by public health, not on the actual day of death. Many states do not update data on the weekend. Hence, the 5-day pattern in the chart, above.

The feared exponential curve was short lived, perhaps due to counter measures. In my state, the curve went linear about two weeks before lock downs were put in force.

Source: United States Coronavirus: 2,424,168 Cases and 123,473 Deaths – Worldometer
Ratio of 7-day Average of New Deaths / 7-day average of New Cases This chart is for my state of Oregon.

This chart shows that over time, the mortality rate is decreasing. This could be because of:

  • More testing, and finding more not very sick cases.
  • An increase in more false positives. We are now testing many asymptomatic people who might be false positives. Due to Bayes Theorem, this could result in many positive tests that are not actually sick people. Asymptomatic people really need to be tested twice – but are probably not tested twice. Two positive results in a row eliminates most of the Bayes false positive problem.
  • The disease is spreading among a younger population who get less sick. Florida has seen its median age for patients testing positive drop to 37, which is down by about 15 years from where it was.
  • The disease itself has changed and is not striking people as hard as previously?
  • Insert your explanation here!

No one yet knows why we are seeing fewer hospitalizations and deaths per new cases discovered. One hypothesis is the increase in testing and finding more asymptomatic cases.

“The easiest thing to look at is case counts, which is not a perfect metric since you have to factor in increased testing,” UCSF epidemiologist Dr. George Rutherford told SFGATE earlier this month. “We’re finding more asymptomatic cases now, so it’s not exactly comparable to March and April, when most detected cases were symptomatic. Now in May and June, we’re catching more asymptomatic cases so it can be hard to interpret since we’re finding more infections.”

Similar thoughts being said about Southern California’s spike in cases. That report features this frequently appearing inane quote:

The continued rise in new cases came amid the first weekend of more business sectors reopening, as bars, card rooms and some personal care services were given the green light to resume operations Friday, provided they take certain precautions.

Due to the incubation period – there is a lag between contact and symptoms or positive tests – a rise in new cases before and on your opening weekend is not due to your opening weekend. Yet the media keeps pushing this false correlation.

In my state, you could not get a Covid-19 test for March and April unless you were:

  • already hospitalized for pneumonia
  • lived in a skill nursing or elder care center and had all of the narrowly defined symptoms (100.4+ degree fever, shortness of breath, etc)
  • or had all of the narrowly defined symptoms and had been in close extended contact with a confirmed case.

By late May, anyone can pay a fee and get tested. My rural community now has drive up Covid-19 test centers – just call ahead for an appointment. They now encourage everyone with any illness symptoms or anyone who thinks they might have been in contact, to get a test. Obviously, we are now testing – and confirming – a lot of mild cases that never got anyone’s attention 2 months ago.

And a personal observation: March 3, 2020 I came down with a head cold. Within a couple of days I had muscle aches and pains and a bad headache and a mild sore throat. By March 7th or so, I developed a dry cough and had a fever of 99.4 (low grade fever for several days). The dry cough lasted until March 23d, went away for a few days, then came back as an even milder dry cough for a few more days before disappearing. The dry cough felt like a ticklish area at the top of the bronchial tubes. I had never experienced a dry cough like that before. In May, I described this to two doctors who both said it would have been nice if I could have been tested in March. One suggested I take an antibody test, but I declined in that the results are not – for now – actionable. And that the is false positive rate is extremely high when the prevalence of a disease remains low (as it is locally).

The media focuses exclusively on a daily body count and daily new cases, neither of which are useful to understanding what is going on – but they do make for scary, fear inducing, click-bait headlines. Basically, the news media’s pandemic reporting has been near worthless. That’s why I have maintained my own web page of charts for my state.

Any comments on this blog about Covid-19 or disease epidemiology are for Entertainment Purposes Only. I have no expertise in this subject and you should assume that I am an idiot and anything I write is stupid and that I probably cherry picked the data or don’t know what I am doing.