Bluetooth Low Energy is unsuitable for COVID-19 contact tracing, say inventors - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: May 11, 2020, 01:37:03 pm
content: In particular, its problems will lead to many false positives and negatives they say.https://theintercept.com/2020/05/05/coronavirus-bluetooth-contact-tracing/

author: m98
author_rank: Frequent Contributor
timestamp: May 11, 2020, 01:58:41 pm
content: Which is kind-of obvious. Getting reliable meter-level ranging from single RSSI measurements with dissimilar devices, antenna orientations, from a body-worn device, in a multipath environment with a multitude of obstacles.It just sounds like a dead-end idea from the beginning. Maybe its good enough to tell if people where together in the same room/building.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 11, 2020, 02:02:13 pm
content: Indeed. It's flawed.It's not even 100% good enough to tell if people were nearby at some point. There are tons of reasons why in some particular conditions, detection would fail, and especially in crowded places with a lot of radio devices.I have no idea of the average "detection" % in real-life settings.In a past project, we had implemented BLE and depending on conditions, it could get finicky. Detecting ALL devices in range could take sometimes several minutes, which may not be compatible with people moving around.

author: jogri
author_rank: Frequent Contributor
timestamp: May 11, 2020, 02:54:32 pm
content: Well, if you would combine BLE with GPS and the gyrometer/inertial measurement unit you could get rather accurate histograms of a persons position. If another device gets registered via BLE you wait until the signal drops out and then compare the (more or less) exact position of both persons over the time they were in proximity. Should yield way better results (you basically eliminate the RSSI/walls issue), but you would have to share your movement/exact position with everyone in your proximity-> won't happen as it would be a data security/privacy nightmare.One possible way to improve the current system would be to install BLE beacons in highly frequented areas that just announce their exact position (+transmission strength)->the app could determine the RSSI of an object that is x meters away if it compares the location of the beacon against its own GPS signal-> triangulation, that would partly counteract the problem that your body is reducing the signal strength in some directions.

author: mark03
author_rank: Frequent Contributor
timestamp: May 11, 2020, 04:26:13 pm
content: In most western countries, GPS has been ruled out over privacy concerns. I think the BLE-alone approach is the only alternative seriously being considered. (Actually deploying it would require a country with at least a basic minimum level of faith in government, and functional high-level decision making, i.e. not the U.S.)Clearly BLE is not perfect, but it doesn't have to be perfect. It only has to be better than the  alternatives.Anyway, the thread title is an unfair characterization (sorry, characterisation) of the article, the title of which wasQuote

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 11, 2020, 05:00:01 pm
content: This comment is from the UK NHSX Covid Tracking app on github.com/nhsx/COVID-19-app-Android-BETA/blob/master/app/src/main/java/uk/nhs/nhsx/sonar/android/app/DeviceDetection.ktCode:// TODO: re-consider this condition after we understand how devices advertise// without supporting MultiAdvertisement feature (isMultipleAdvertisementSupported == false)// This allows for them to run without crashing but probably not advertise as expected.// See: https://stackoverflow.com/a/32096285/952041// Here is part of the previous device detection logic that blocked Huawei P Smart phone.// After commenting it out we are not sure if the phone's advertising works// with our Bluetooth scanning process:// || (bluetoothAdapter.isEnabled && !bluetoothAdapter.isMultipleAdvertisementSupported)// TODO: We need a real device to test Bluetooth scanning if isMultipleAdvertisementSupported == false// TODO: We need analytics to identify number of devices that fall into this bucket// and if they scan correctly

author: vodka
author_rank: Frequent Contributor
timestamp: May 11, 2020, 06:22:03 pm
content: Quote from: blueskull on May 11, 2020, 04:32:00 pmThat is literally, the state declares a State of exception. The goverment legally can't intervene the communications massively without a court orderQuote from: blueskull on May 11, 2020, 04:32:00 pmYes, it has matter that we know the routes with accuracy, because it is not same put 10 persons in quarantine than 10000 persons.

author: David Hess
author_rank: Super Contributor
timestamp: May 11, 2020, 06:54:38 pm
content: Quote from: blueskull on May 11, 2020, 04:32:00 pm... no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularity describing the place to be searched, and the persons or things ...So what crime did everybody commit for which probable cause exists?https://en.wikipedia.org/wiki/Warrant_(law)#HistoryWe won that war so we do not have to put up with General Warrants anymore.

author: cdev
author_rank: Super Contributor
timestamp: May 11, 2020, 07:30:00 pm
content: But maybe 14 year old jennifer Zhang's high school science project makes all this fuss unnecessary.We certainly owe it to ourselves to find out. (See attached PDF)She won a prize for it.Quote from: David Hess on May 11, 2020, 06:54:38 pm

author: Marco
author_rank: Super Contributor
timestamp: May 11, 2020, 07:41:51 pm
content: Impressive science project ... but I don't think you can't get that dose from an ingested medicine. Even with an inhaled one I'm kinda scared what that amount of it would do to everything else but the virus.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 11, 2020, 07:50:00 pm
content: Quote from: David Hess on May 11, 2020, 06:54:38 pmSnowden's revelations ruined that dream a bit.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 11, 2020, 07:59:57 pm
content: Here's a thought for Bluetooth contact tracing. If you can use the RSSI to calculate distance as per the equation*Distance = 10 ^ (( MeasuredPower – RSSI)/(10 * N)) , it would be possible to penalise people for breaching social distancing rules as their recorded RSSI is too high. Or at least give them a proximity notificaction!* Source: How to Calculate Distance from the RSSI value of the BLE Beaconhttps://iotandelectronics.wordpress.com/2016/10/07/how-to-calculate-distance-from-the-rssi-value-of-the-ble-beacon/

author: cdev
author_rank: Super Contributor
timestamp: May 11, 2020, 08:33:08 pm
content: Could you explain a bit more?This paper on RESV + MERS said that the dose was attainable and sustainable by multiple dosing.(see attached picture here is the original paperhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC5307780/)Resveratrol is proposed elsewhere as likely good for most people who are at high risk for COVID-19. Papers have been written just about that.Quote from: Marco on May 11, 2020, 07:41:51 pmAlso, weights of a substance that is inhaled are smaller not larger than can be ingested. Large amounts of resveratrol are toxic but that is a dose that nobody would take. According to this other study the amounts needed would be sustainably taken. With the caveat that I am not a doctor and have no idea if this would work, and although it is entirely reasonable to theorize that smaller doses might have the desired result of reducing the severity of infection so as to make it less dangerous, but perhaps not completely preventing it, its also a notoriously unpredictable situation that nobody has any right to or should try to second guess.Something similar has been done with virulent pseudorabies virus and piglets.Seehttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164078/Actually, a number of papers have replicated this kind of experiment in a number of different animals and viruses.Note: I have NO idea if this would work against COVID-19.I would assume it won't. Take precautions! I would rather make a fool of myself wearing masks and gloves and washing my hands six times a day than get a potentially fatal disease.Also MERS is a different SARS-like betacoronavirus.To my knowledge COVID-19 still has not been tested with resveratrol. I've run out of entities to call about this. If you live in other countries, you might consider asking them if they have tested it. just to jog their memories that they should.Tell them we may be dropping the ball.Point them at this:Sirtuins Are Evolutionarily Conserved Viral Restriction Factors-https://mbio.asm.org/content/mbio/5/6/e02249-14.full.pdf

author: Zero999
author_rank: Super Contributor
timestamp: May 11, 2020, 10:32:24 pm
content: I admit I’ve not read it yet but thought I’d chime in anyway. It doesn’t have to be perfect and no system can be, as someone might pick it up from an object. The app just has to ensure people who might have it get tested, without there being too many false positives to overwhelm the system. That’s all that’s needed to keep the R number below one, without isolating everyone.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 12, 2020, 04:23:47 pm
content: Seems a bit click baity to me. The app doesn't claim to be super accurate, and if someone has their diagnosis confirmed it can at least show if they've been self isolating, or been in relative close proximity with lots of people. And of course, it can't know if someone has been in contact with someone without a phone.It isn't meant to completely track everyone, the question is - is it better than nothing?No-one is claiming an app can magically know everyone who will get it, but it should at least help modify peoples behavior by informing them if they've been near a confirmed case. They'll probably have to tweak it to reduce the false positives, and there will be plenty of false negatives but some feedback is better than none.

author: nali
author_rank: Frequent Contributor
timestamp: May 12, 2020, 04:43:15 pm
content: AIUI There are essentially 2 types of systems being proposed - the centralised and the peer-2-peer.The centralised system has everyone's phone just reporting its position to a server then everything is worked out from there - which obviously raises privacy concerns.The P2P relies on BLE detection which has several flaws. Apart from the signal itself being subject to environmental influences, different phones report signals in different ways e.g. I had a Samsung J3 which reported the same signal some 40dB higher than all my other phones. Also, not all phones and OS versions support advertising.I don't know how they've considered scenarios like I could be on a bus or train, and a few feet away from someone at a stop or station. Or cars in adjacent lanes in traffic, building with partition walls etc etc etc..

author: cdev
author_rank: Super Contributor
timestamp: May 12, 2020, 05:02:38 pm
content: Quote from: Buriedcode on May 12, 2020, 04:23:47 pmBluetooth low energy has enough range to be received much further away than what is a safe distance for COVID-19. Especially if there are metal objects nearby which may act as RF reflectors or blockers.For example, lets assume that 40 people are riding on a bus and that 35 of them have cell phones with BTLE turned on. The interior of the bus, desite the existence of windows, will be likely to concentrate the RF so that all the phones receive more signals from one another even if they are on opposite ends of the bus.So, as far as proximity, even if only four people are near enough to somebody with covid-19 to possibly have picked up the virus, it would be likely that far more than four people might show as having been close, even people far away. Most of us have been in a large round room, or one with a curved roof. A so called whispering gallery, You can stand on one side of the round room and somebody else can stand at its exact opposite nodal point and hear you whisper. Effects like that are common with RF.An RTLSDR can be useful in showing how much UHF signals vary as you move an antenna around.

author: Zero999
author_rank: Super Contributor
timestamp: May 12, 2020, 07:16:25 pm
content: Quote from: cdev on May 12, 2020, 05:02:38 pmI don't see how any of that really matters. Over the last 7 weeks we've had blanket social distancing: assuming everyone is infected and physically isolating everyone from one another, as much as possible to prevent transmission. This was a very blunt tool which cut R below 1, at huge economic cost. What the government should have done right from the beginning, was more testing and contact tracing and testing, as has been the case in Taiwan and South Korea, which haven't had so much social distancing. Now the infection rate has been reduced to manageable levels, the idea is we can sharpen our a approach and work towards only isolating those who are most likely to have the virus. Ideally we should be able to test everyone who's most likely to have the virus, then they can be free to return to work.The app is just another tool to help with contact tracing. Now we only need to isolate everyone on the bus, rather than the whole country and because it's a relatively small number of people, it's more feasible to test everyone one of them and the friends and family of those who test positive. In the UK, the app will be voluntary and I believe it will still have a positive effect, even if not everyone uses it. If it's proven to be effective enough, then there should be some incentives for people to use it such as being able to jump long queues to enter supermarkets more quickly and perhaps money off certain items such as toilet paper.Other measures which many may consider to be big-brotherish will be required. For example, if a nightclub is opened, everyone going will need to show photo-ID on the door, then if anyone feels unwell afterwards and test positive, everyone who visited the club on that night, along with anyone they've been in close contact with, will have to be tested and self-isolate if appropriate. A similar thing will need to be done in other situations where social distancing is impossible, such as crowded public transport. The app should only be a small part of the programme of testing and treatment/isolation of the infected.If governments invest hugely in contact tracing and targeted testing, we can all get back to work and play fairly quickly and the tax revenues will easily pay for it.To those who are concerned about big brother: they have a right to be, but don't forget many of these measures will be costly and governments won't want to spend money on them when they're no longer needed. I can't even see China bothering to waste money on recording the name and address of everyone entering a crowded bar.

author: cdev
author_rank: Super Contributor
timestamp: May 12, 2020, 08:18:07 pm
content: Accuracy matters a great deal. IMHO.If they are using a technology that cannot be accurate enough according to its own developers, maybe its not the right technology!

author: Buriedcode
author_rank: Super Contributor
timestamp: May 12, 2020, 08:51:32 pm
content: Quote from: cdev on May 12, 2020, 08:18:07 pmThe only alternative would be to use absolute location - GPS - which, as pointed out raises obvious privacy concerns. Also, I don't believe Apple allow for continuous location tracking on any app. I'm sure there will be a version that uses location tracking, but users would have to opt in, and I'm sure the powers-that-be are pretty hesitant because of an inevitable backlash.The phrase "accurate enough" implies there is a known level of accuracy desired. There isn't. Even if somehow current smart phones had the ability to measure proximity to other phones with mm accuracy - at what point would it flag up "possible contagion contact" ? Would it be a sliding scale? Would that only be inside enclosed spaces? All the app really needs to do (for now) is to know whether or not the phones owner has been tested, and the result, and how often they have come into reasonably close proximity to other users that aren't in their household. I'm sure the devs working on this aren't making any kind of claims about efficacy - right now they're busy ironing out bugs and it will be an on-going experiment.

author: Marco
author_rank: Super Contributor
timestamp: May 12, 2020, 09:09:37 pm
content: How about using BLE for a conservative estimate and then using 20-22 kHz audio for ranging when people are near?Or maybe even just use audio period. Autocorrelation of a chirp signal don't care about multipathing.

author: jogri
author_rank: Frequent Contributor
timestamp: May 12, 2020, 09:21:13 pm
content: Quote from: Marco on May 12, 2020, 09:09:37 pmThe "RSSI" would be absolutely terrible as soon as you put your phone into your pocket. Plus, having a microphone that is listening all the time is actually worse than having GPS running 24/7 when it comes to privacy. You need at least 60% of the population to use this app, if you have to admit that you (the government) have basically created a bug that is spying on people when they use the app no one will use it.

author: Marco
author_rank: Super Contributor
timestamp: May 12, 2020, 09:30:08 pm
content: Quote from: jogri on May 12, 2020, 09:21:13 pmAutocorrelation with a chirp doesn't get you RSSI, it gets you multipath insensitive time of flight for the closest path. As for SNR, repetition, repetition, repetition. (Ping-pong ranging makes it a little more complex than that, but it's just audio ... almost nothing in audio is processor intensive any more by today's standards.)QuoteNo it's not.With an open source app and tons of researchers verifying the integrity of the appstore version you can be certain it doesn't do anything with the data except ranging and identification and that that data does not leave the phone.With GPS data in a central database however no such verification is possible, you're reliant on trust of the database maintainers.

author: Zero999
author_rank: Super Contributor
timestamp: May 12, 2020, 10:02:24 pm
content: Quote from: Buriedcode on May 12, 2020, 08:51:32 pmYes and I doubt the developers themselves are epidemiologists. Any small degree of accuracy is better than the current situation. Even if it errs on the side of caution, generating some false positives, it will still mean fewer people, than now, will need to be isolated to control the spread.

author: jogri
author_rank: Frequent Contributor
timestamp: May 12, 2020, 10:03:43 pm
content: When i said "RSSI" i meant loudness of the recieved signal (that's why it is in quotation marks). Fabric dampens the volume quite a bit, and combined with the fact that the microphones were never designed to be used at this frequency range the SNR will be abysmal.Btw, good luck telling the general pulic that an app that is developed by the government and will most likely be verified by researcher that are working for the government (universities etc) can be trusted... You just need one guy telling everyone that said app is used to spy on people via the microphones. And you have to confirm that "yes, the app is constantly listening via the microphone BUT...". I don't think it would matter what comes after the "but", as soon as you say it the damage is done.

author: cdev
author_rank: Super Contributor
timestamp: May 12, 2020, 10:38:49 pm
content: There is a whole body of new technology that is attempting to make it easy for autonomous vehicles and robots to navigate inside of buildings. Its not something that a cell phone can do reliably yet. (although they are working on it quite a bit) The CPUs and GPUs on small computers arent powerful enough. If they used a combination of inddor beacons and visual cues and GPS and inertial sensors and maybe autio becons in phones - they might be able to do it but that would (if it worked) eat up battery like crazy.Actually, its my understanding that the risk of catching coronavirus outdoors is very very much reduced from indoors. Most buildings are not well ventilated this is the real cause of their being dangerous when people in them have infectious respiratory diseases.I think universal healthcare and sick leave (so people dont go to work when they get sick, and then seek treatment) and other comon sense things, are what they should be concentrating on.Adequate ventilation, especially if they intend to switch people to electric heating (from natural gas) will mean much higher energy costs in the winter, although they could reduce a lot of that cost with heat exchangers, a good retrofit. They might recoup costs on savings on air conditioning.They should also install UVC fixtures in places like classrooms where people congregate during the day, and then turn them on at night to disinfect surfaces. Also some surfaces can retain viable virus for extended periods of time. (more than a week is conservative estimate, they tested a suite of rooms on one of those cruise ships17 days after all the crew and passengers had left and there was still lots of detectable COVID-19 on surfaces) The best surface for antiviral activity is copper, plastic is very bad and viruses can last for many days, perhaps even as long as two weeks on plastics. So, it might be smart to analyze what objects people touched the most and transmitted viruses (dorknobs would be up there) and replaced them with copper sheathed versions.Unfortunately, plastic is all around us.

author: SilverSolder
author_rank: Super Contributor
timestamp: May 12, 2020, 10:44:00 pm
content: The best solution has to be some kind of biotech - a vaccine or a treatment that works reliably without unacceptable side effects.

author: cdev
author_rank: Super Contributor
timestamp: May 12, 2020, 10:46:39 pm
content: Thats what we're all hoping for.Quote from: SilverSolder on May 12, 2020, 10:44:00 pm

author: cdev
author_rank: Super Contributor
timestamp: May 12, 2020, 10:57:27 pm
content: Quote from: jogri on May 12, 2020, 10:03:43 pmIf they coated particularly problematic elements in indoor environments with RF damping foam, they might be able to get significantly better accuracy with the RF location. At least it might mitigate the false positives somewhat, maybe.There are some cool visualizations out there of 2400 MHz RF bouncing around showing how its possible, sort of, to use wifi signals in a sort of passive radar to "look through walls" That seems to me to be a big potential source of problems. Suppose you are separated from somebody with COVID-19 by a wall. They may be just a meter away from you but there is little risk of contagion because there is a wall presumably with no vents through it.A dumb BTLE and GPS system even if perfectly accurate is never going to realize that you're safe and is going to flag you as a potential sickie for the "contact" that never occurred. The only way around that will be to draw a line slightly less than two meters away from every exterior wall in your space and never go into that "border zone".Note that this kind of data is also going to be used to price health insurance. Thats probably one of the real reasons they want it.No doubt this research is paid for with DOD/MOD funding.Well at least they arent implanting hidden microphones into cats any more.

author: Someone
author_rank: Super Contributor
timestamp: May 12, 2020, 11:17:40 pm
content: Quote from: jogri on May 12, 2020, 10:03:43 pmYou might have missed the circus going on at the moment with the apps already rolled out.. the messaging has been very carefully curated/controlled to say happy things but carefully framed to avoid denying the privacy issues. Political doublespeak is working on most of the population and they just don't notice.

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 12:36:30 am
content: The places where accuracy matters the most will be impossible to get GPS signals into If there is a so called leaky coax system (used for cell phone operation) they tend to create strange anomalies on GPS tracks. (I know because I often carry a GPS logger when I am in the city just so I can see visually later where Ive been.)Sometimes when I go into a tunnel it does pick up signal for quite a ways. But the location during that section of trace is never right, its bizarrely wrong.I have never been on the London Tube but it appears to be exactly like NYC subways in terms of people being close together. The kind of places where "social distancing" is impossible. The worst areas are the ones where people are moving very fast in both directions. (curious, do people in London obey UK traffic rules, "driving" on the left hand instead of the right, when walking??) Here the lanes for walking mimic the cars, so youre always walking on the right and the opposite dirction is on your left.Anyway, in Manhattan, especially in major subway transit points, there are huge numbers of people all walking through the same spaces, where its impossible to stay two meters apart.. (See "Koyaanisqatsi" by Godfrey Reggio, a film from 1982 of fast motion photography for some great scenes taken in NYC.) During the morning or evening rush hour (both of which are actually two or three hours long) there are lots of people in places like multilevel stairways (some people out of breath and breathing deeply) and six way intersections, and long two way escalators underground. You cant adjust your position once you get on the escalator if somebody starts coughing, during rush hour there are people very close together. They have a small space in the middle between the up and down escalatators and each side's stairway is narrow, maybe 1M wide. These escalators are very long and whatever ventilation they have is of the "air blows in one end and out the other" variety. Thats no longer adequate.That is a problem. they need more fresh ventilation in the middle of those long stairways and similar spaces. Instead of focusing their efforts on half-baked schemes that dont seem destined to work for their intended purpose, they should concentrate on the actual problem, the epidemic and mundane seeming problems like ventilation. Also they should stagger arrival times for workers.To spread the commute hours out so the density is reduced.Specifically, making being in tight spaces and public transit, particularly, safer.Because the main reason cities like New York and London work as well as they do is GREAT public transit.People all getting private cars is a non starter, its just plainly impossible. Also many people dont like cell phones, and either dont have one or if they do, don't use it as these people who seem glued to cell phones do. I personally prefer reading when I am away from computers, things like physical newspapers and books. And I'm sure I am not the only one.Quote from: Zero999 on May 12, 2020, 10:02:24 pmIts technically impossible to get what they say they are trying to do, isnt that what the code comments seem to be saying?GPS does not work in subways - at all. Not at al, nor does it work in most city buildings, at all. Outdoors, relative to indoors, there is practically no danger, maybe not no danger, but it is much much reduced. Even under the best of conditions, the only place GPS is going to be accurate is outdoors. Indoors, because the GPS antenna in a phone (typically a chip antenna on the PCB) is never going to be oriented as it should be, its always going to be next to this big thing that easts up most of the signals. (your body) So the location it calculates jumps around a lot unless you take care to make ot accurate. (I put my little tracking box in the "cd" pocket in my backpack and go to great lengths to check it that it hasnt shifted so the top is facing the sky. And when I go down in the subway I know from experience the GPS trace is going to be useless and vanish so I turn it off so as not to create a big jag between when I go into the subway and come out. Instead I get individual GPX files. (cheap non-RTK GPS logging produces various kinds of files, mine produces a "GPX file" the way its set up now. I use a program called GPSBabel to turn those traces into KML files.

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 13, 2020, 01:43:07 am
content: Not a fan at all of this surveillance but it's inevitable. They'll do it "for our safety" but once the tech is there they'll just keep using it.In Toronto they are getting people to install a tracking app if they want to use the transit and such. (just saw a quick blurb on news so don't know the full details, maybe it has not happened yet and it's just a suggestion)I mean, I kinda get it, and on the surface it does seem like a good idea, especially if it can also be used to quickly alert anyone that has been in close contact with someone who tested positive, but it still gives me really bad vibes. Almost "mark of the beast" style.What really needs to happen is to move towards work from home being the standard instead of a niche thing. That would greatly reduce the amount of traffic. Not only would it be better for the environment it would be better for us too. Especially in big cities where people have like a 1 hour commute. You could not pay me enough for that. I sometimes take it for granted that I live in a small city and work is like 10 minutes away from my house.

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 02:00:16 am
content: It depends on the employer. Sometimes being at work is really fun.I think the general plan/trend is one where there are a lot fewer jobs and a lot of them are outsourced or automated. The outsourced jobs will probably eventually be on the other side of the world. Quite possibly being done at night by the people there. (India is "The Back Office of the World" now, you know) But the surveillance will remain because people wont have anyplace else to go but they still will be expected to move elsewhere if they have no money. .This is what happens when you have a big problem with groupthink and nobody has the common sense to call them out on it. "hey, this doesn't make sense" Like should have occurred in the Challenger disaster.Quote from: Red Squirrel on May 13, 2020, 01:43:07 amWhat about people who dont have cell phones or whose cell phones dont support this "app"?(Which it seems is unlikely to actually work)

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 13, 2020, 06:24:23 am
content: Quote from: blueskull on May 13, 2020, 01:47:51 amYeah that's a good point, and even now might be too late. All these people working from home temporarily might light a bulb over the CEOs' heads. "If this job can be done from anywhere..." What really needs to be stopped is this whole globalization thing. Companies should be required to keep at least a certain percentage like say, 80% of work work within the country. That's never going to happen though.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 13, 2020, 07:22:47 am
content: Don't people already look ridiculous enough walking about with their heads stuck in phone apps 24/7without another app that will waste their time till they realize it's not their phone at fault, but a dud app

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 13, 2020, 09:02:20 am
content: For those playing at home, here is how the British boffins simulated a 'real world' BLE environment at R.A.F. Leeming this April.(uk) NHS COVID App Closed Beta Test Data Gathering Planhttps://github.com/nhsx/COVID-19-app-Documentation-BETA/blob/master/Beta%20Test%20Staged%20Exercise.pdfNot so sure this is a real world scenario for a public transit system, supermarket or campus, but at least they were using some kind of scientific method.Battlefield tested:https://www.raf.mod.uk/news/articles/rafs-digital-airbase-tests-covid-19-tracking-app/

author: SilverSolder
author_rank: Super Contributor
timestamp: May 13, 2020, 10:12:13 am
content: Quote from: Red Squirrel on May 13, 2020, 06:24:23 amWe are all divided into groups called "countries" because it is human nature to think of our "country" as a kind of extended family, that we want to take care of and that we expect to take care of us too.It becomes increasingly difficult make the emotional connection, beginning with your own actual family (high divorce rates etc.)... your neighbourhood... town... state/province... country... continent... planet. Arguably, the higher up you make it in that pyramid, the better person you become?

author: tszaboo
author_rank: Super Contributor
timestamp: May 13, 2020, 12:49:32 pm
content: I did a test before for RSSI distance estimation. There was two dev boards, fixed location, fixed environment, pinging each other for hours, 2.4GHz. The RSSI values went anywhere from -52dBm to -40dBm, average is -45dBm (1.2m distance), bell curve distribution. And that with simple, unobstructed, well defined antennas, custom firmware, kept in place during the test, no humans around, no large metal surfaces. 6dB means double the distance.Different phone manufacturers will used different bluetooth implementation, with different gain on the antenna, different margin to the +10dBm legal limit, different algorithm to save battery power. The phone antenna has directionality. This doesnt work, even in the best scenario.

author: Marco
author_rank: Super Contributor
timestamp: May 13, 2020, 03:13:30 pm
content: Someone already had the ultrasonic idea and applied it.https://www.novid.org/They make a good point that it also solves another false positive problem with RF, sound doesn't go through barriers as easily.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 13, 2020, 03:16:06 pm
content: Quote from: Marco on May 13, 2020, 03:13:30 pmUh huh, but I always find it interesting when people claim to reliably emit AND record ultrasounds on most mobile phones just using the existing hardware.

author: Marco
author_rank: Super Contributor
timestamp: May 13, 2020, 03:46:32 pm
content: Near ultrasoundis actually part of android compatibility test suite.Knowing that should make it less interesting and more self evident.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 13, 2020, 04:42:45 pm
content: How about good old fashioned 1990's style IRD? We wear an IR transceiver on our facemasks.Seriously though, BLE contact tracing apps are reliant on data exchange after a BLE connection has been made between two devices. In practical terms, kein problem in a low density environment with few people, but what about walking through a high density (high risk) place like a crowded metro station? Is there enough time for devices to advertise, connect, exchange, hang up and repeat, when you're walking as quick as you can through the 'danger zone'? How many devices get missed?btw I came across this informative primer on BLE Advertising, which is the core technology for most contact tracing apps.https://www.argenox.com/library/bluetooth-low-energy/ble-advertising-primer/

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 06:55:54 pm
content: How about a system where people are totally in control that doesnt connect up to anybody or anything else that merely warns them when somebody else is too close with an audio alarm.No surveillance state anything. Dumb electronics only. using sound TDOA and with no means of offloading data.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 13, 2020, 07:21:45 pm
content: (Near) Ultrasound/Sonar would circumvent the problems with EM-reception field strength indication vs. physical contact, but most people carry their phone in pockets, introducing lots of noise and dampening, making a distance measurement hard. And all this effort is thwarted by someone sneezing into his hand and touching a doorknob, or not for elderly or young kids.This is why I think the approach to trace contacts and possible infections via smartphone is ill-fated, i doubt there is an advantage over the regional physical distancing rules indicated by test/amount of newly infected people. It would take time to crunch the data, make the decision and will probably affect as many people as to locally check by infection rate if measures for a whole area are needed. Both methods just follow what this virus is doing, but given the long incubation time only preventative methods could make an impact.Psychologically i think rules work best when everyone is required to e.g. wear face masks, keep distance and such, not singling out subgroups.

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 08:22:56 pm
content: Quotas like that are being disputed as we speak, and indeed, if India wins its case against the US the changes are binding on the entire world. Many businesses may lay off their old expensive employees and rush to get the newer cheaper ones. This may be why governments are suddenly so keen to keep track on people?the new arrangements are not being fair to anybodywhen they make the wages so low. (Even if now they are 'legal')Quote from: blueskull on May 13, 2020, 06:45:49 am

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 08:29:30 pm
content: Quote from: Syntax Error on May 13, 2020, 04:42:45 pmIt looks like battery life may become an issue. How much, its hard to say.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 13, 2020, 09:14:38 pm
content: Quote from: SparkyFX on May 13, 2020, 07:21:45 pmI would personally not expect it to really be of any use outside of ideal conditions indeed.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 13, 2020, 09:22:21 pm
content: Quote from: cdev on May 13, 2020, 08:29:30 pmMaybe a moot point for many Android smart phone owners as the Covid tracking apps only run on the latest edition of the operating system. Globally ~60% of Android phones are not up to version 6.0, me included. 6.0 is baseline for the Australian and the UK Beta apps. On the other hand, Apple iOS offerings at 10.0 would only exclude some 5% of users. However, iOS does BLE in it's own unique 'designed in California' way.We should also take note of the success of South Korea at fighting the spread of the virus as their contact tracking is a mix of GPS, cell tower triangulation and bank transaction analysis. Basically, throw away your electronics and pay cash.

author: Someone
author_rank: Super Contributor
timestamp: May 13, 2020, 11:05:16 pm
content: Quote from: SparkyFX on May 13, 2020, 07:21:45 pmThere are a non-trivial number of people who carry their phones in a bag. Pocket locations/sizes/availability don't always match phones. Bluetooth was the best of the options already in place and ready to use.Quote from: SparkyFX on May 13, 2020, 07:21:45 pmThere are good motivations for digitally enhanced contact tracing, partly that peoples memory is really unreliable. Being able to reliably know where someone was during the period they might have been infectious is valuable alone. But when that location information is then cross-referenced against other people a so they are notified with little effort on their part, its a possible game changer.The main justification for such an automated system is that you can reduce broad "sledgehammer" measures like arbitrary travel constraints (border straddling towns for instance. Instead focus on just the people who have higher likelihood of having caught the virus. We've already seen this sort of thing by applying additional restrictions to travellers coming across borders. That has its problems, trying to convince a subset of the community that they need to undertake an individual quarantine/isolation while 99% of people continue with their daily lives has been a hard sell already:https://www.abc.net.au/news/2020-04-15/man-jailed-for-breaching-coronavirus-quarantine-by-leaving-hotel/12149908Imagine instead of being arbitrarily quarantined, travellers were only segregated if they were within [arbitrary measure of infectious distance/trave] of confirmed cases. And such restrictions could be applied to individuals retroactively, after discovering new applicable cases. That could be a big win for the vast majority of the population. Keep up the physical distancing etc, and people who do that will be less likely to have restrictions placed on them individually. Its handing back control to the individuals, but both sides need to have a trusted system in the middle to mediate it.

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 11:57:19 pm
content: But when people are outside, there is virtually no chance of infection, and as I was trying to explain, when people are indoors the locations reported and saved to logs are invariably wrong. They are not accurate indoors. Most dangerous encounters are not in RF transparent buildings. They are in big buildings (work) or underground, neither of which is a good environment for location capture. Dont believe me? Look into "SLAM" on github.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 14, 2020, 12:02:44 am
content: Notification: Your phone was recently close to someone who has tested positive for Covid 19. You must self isolate immediately.Response: Like what ever, wasn't ME holding the phone anyway.

author: Someone
author_rank: Super Contributor
timestamp: May 14, 2020, 12:21:21 am
content: Quote from: cdev on May 13, 2020, 11:57:19 pmUnreliable measures of proximity are still vastly superior compared to trying to get an individual to recall when/where they were. Perfection being the enemy of good... any system needn't be perfect, but simply a substantial improvement over whats already existing.Quote from: Syntax Error on May 14, 2020, 12:02:44 amThats just the balance/arguments over who should take responsibility, individuals or a state actor. Every society/country will take a different position on that, and individuals may feel unhappy with the balances chosen.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 03:09:12 am
content: Security theater that is totally inaccurate is worse than nothing. What they need is contact tracing. Do you have a GPS tracker? Do this, turn it on, take a walk in a major city, going inside some buildings and going down into the subway. Then dump the trace and convert it into a KML trace. Since you cant upload KML here, maybe zip the file. Upload that. just do that. That will prove my point.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 14, 2020, 04:50:03 am
content: Quote from: cdev on May 14, 2020, 03:09:12 am... And you.. expect the majority of citizens in an entire country to do this?

author: Someone
author_rank: Super Contributor
timestamp: May 14, 2020, 05:41:47 am
content: Quote from: Buriedcode on May 14, 2020, 04:50:03 amThe fair comparison would be to ask the same people, before they've looked at the data, to draw the same information on a map and timestamp it. Because thats what happens at the moment.Do people give this information when asked for it? Most of them do.Should people be required to give this information when asked for it? Sounds political...Should people be forced to continually provide this information? Now you're certainly getting political

author: Marco
author_rank: Super Contributor
timestamp: May 14, 2020, 10:53:56 am
content: Quote from: cdev on May 14, 2020, 03:09:12 amThat depends, there is a good chance that the security theatre is just saving face. I personally believe a lot of Europe is at the tail end of the pandemic ... regardless of lockdown. If security theatre lets governments end the lockdown without admitting they screwed up implementing it, well it's better than staying pot committed to lockdowns.A bit of experimentation with the tech to see what works can still be useful for when we encounter a properly dangerous pandemic too.I'm not sure even a bag attenuates ultrasound beyond what signal processing can rescue from noise in reasonable time.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 11:53:42 am
content: We are dealing with viruses the wrong way for the 21st century.Somebody brought up a concept yesterday,"Original Antigenic Sin"Read up on the importance of making sure the first vaccine for a disease family that somebody gets is the right one.The stakes are very high because a wrong vaccine will make people much more vulnerable to a serious disease later Some vaccines convey broad immunity, some convey narrow immunity that prevents immunity to other strains of a pathogen.-----------------"We live in a sea of viruses, some of which are human pathogens. These pathogenic viruses exhibit numerous differ-ences: DNA or RNA genomes, enveloped or naked virions, nuclear or cytoplasmic replication, diverse disease symptoms, etc.Most antiviral drugs target specific viral proteins. Consequently, they often work for only one virus, and their efficacy can becompromised by the rapid evolution of resistant variants. There is a need for the identification of host proteins with broad-spectrum antiviral functions, which provide effective targets for therapeutic treatments that limit the evolution of viral resis-tance. Here, we report that sirtuins present such an opportunity for the development of broad-spectrum antiviral treatments,since our findings highlight these enzymes as ancient defense factors that protect against a variety of viral pathogens."(Source: Koyuncu E, Budayeva HG, Miteva YV, Ricci DP, Silhavy TJ, Shenk T, Cristea IM. 2014. Sirtuins are evolutionarily conserved viral restriction factors.https://mbio.asm.org/content/mbio/5/6/e02249-14.full.pdf)

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 14, 2020, 12:28:47 pm
content: I think that going on and on about the RSSI strength detection thing and thinking it has to be perfect or it's useless is missing the point.The contact tracing app is not meant to be 100% perfect.if it can work even a bit, it can speed up transmission tracing.which will catch some transmissions before the transmitted to person gets sick enough to be tested and get diagnosed (by which time they have passed it on themselves). so will bring down the reproduction number.we see in the studies on clusters so far that exposure risk relates to the amount of viruses being expelled form the source vs time near the source. You can do worse in a room far away from someone who is just breathing if you are there for hours, than if you are right next to someone who is singing or shouting or exercising for a few minutes.having the app log some kind of proxy for distance *and* time spent nearby would be useful, I suspect. Even if not perfectly accurate. seems that it only logs contact that has lasted around 15 minutes? seems a shame it can't measure times with a bit more accuracy. or at least multiples of 15 minutes.

author: nali
author_rank: Frequent Contributor
timestamp: May 14, 2020, 12:44:30 pm
content: This is a pretty interesting blog post on the UK app:https://www.ncsc.gov.uk/blog-post/security-behind-nhs-contact-tracing-app

author: David Hess
author_rank: Super Contributor
timestamp: May 14, 2020, 03:39:07 pm
content: Quote from: nali on May 14, 2020, 12:44:30 pmThe direct or of the National Cyber Security Centre (Ian Levy) is explaining how they are going to protect your privacy and security using a closed source application? That is a laugh.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 14, 2020, 03:45:54 pm
content: Quote from: David Hess on May 14, 2020, 03:39:07 pmIndeed.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 04:03:06 pm
content: But you won't get indoor traces that are of any use, unless the person is in a flimsy 1 or 2 story wooden building and the antenna is pointing up and a whole bunch of other ifs.let me point you to the subject area.. "SLAM" - Simultaneous location and mapping..Indoors is where people get infected, I suspect. 99% of the time.Indoor mapping is a big technical field now because many people do want to build devices that can navigate indoor spaces and know where they are. Now I am by no means an expert but I do try to keep up on this and over the years Ive fooled around with it quite a bit, especially with GPS RTK.There is a very very large difference between indoors and outdoors. As it stands right now all indoor mapping technology is basically crap. Outdoors is a different story but still very bad in "urban canyons" i.e. cities unless one goes to lengths to optimize performance in ways that are not feasible in a cell phone setting.Also, constantly transmitting and receiving beacons is likely to drain battery life quite a bit. (GPS now can be done with very little battery) Presumably each device will contain a log of all the other BT IDs it receives and when. If somebody is in the range of another BT ID for an extended period of time, that might be valuable if the people were outdoors and it could be verified that they were proximate to one another. But then the risk of transmission is much reduced because they are outdoors. So pretty unlikely to be useful, except as a non-covid-19 surveillance tool.Indoors you'll notice that in cities, when people go indoors there usually is no GPS fix. Logged BT IDS will not be telling you where they are because there is no 3D fix. Unless they are right next to a window and then the lack of enough satellites will make the fix jump wildly around because the GPS signal is boucing off buildings. It gets worse the further they are from windows. newer GPS systems that are coming online use multiple bands and are substantially more accurate, outdoors, in urban canyons, but not inside buildings. And all GPS antennas like to be pointed up. Otherwise accuracy goes all to hell.Read the literature. If you can find one paper that shows a technology that works with existing devices and which allows consistent indoor localization to the kinds of accuracies that can be reasonably used for contact tracing, I will be very surprised. In particular, the antennas in cell phones are not up to the task. Most of these experiments are done with robots (sometimes in this setting they are called "rovers") Look at the literature, the state of the art now has to use multiple inputs - particularly optical- video inputs and photogrammetry to get a reliable idea of location, based on the last good GPS fix, typically before they entered the building. They also use compasses and IMU. Thats called "dead reckoning"Triangulation with cell phone sites is also nowhere near accurate enough indoors. What about wifi access ponts logged by Google, etc? Again, not accurate enough to help much with this fine level of detail. What about visual tracking? That has a lot of romise, especially when using multiple cameras and especially D-RGB (RGB with depth sensors, similar to the MS Kinect devices)Quote from: julianhigginson on May 14, 2020, 12:28:47 pmYou have to understand, once somebody drops off the GPS and goes underground they could literally be anywhere. If they fill the metro stations etc. with BT beacons, thats still not going to get it to the level of accuracy it needs to be.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 14, 2020, 04:24:04 pm
content: Quote from: cdev on May 14, 2020, 03:09:12 amI do agree with that. If it's inaccurate enough that you can't actually deterrmine for sure that people have been in "contact" (thus in close proximity enough that it could matter as far as virus propagation is concerned), then it's basically useless, and worse than useless: if you still rely on it to take any kind of action or issue any kind of analysis, that's wasted time and money that could be better invested in something else.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 04:31:16 pm
content: If it becomes wrong and or arbitrary, that is a way to guarantee it does not work for its intended purpose. because people will not cooperate if they feel that the system is not taking great pain to be accurate and fair.(Do we want a world like Terry Gilliam's "Brazil"?)Quote from: SiliconWizard on May 14, 2020, 04:24:04 pmCreating lots of jobs may be one of its main goals.Look at Prohibition in the US during the Depression.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 04:44:38 pm
content: I'm just saying, that the data recorded when somebody is indoors or in subways, (or tunnels) is likely to be useless, or close to it.Trains, above ground? May be better but stil most trains now have metal cars with tinted windows. Tinted windows oftentimes eat up a lot of GPS signal, but trains without tinted windows, they may be able to get a fix from time to time.Enclosed places, more so than outdoors, are where people get infected.Quote from: Buriedcode on May 14, 2020, 04:50:03 amArent they supposed to install an app that uploads all sorts of data that in essence, does that? My point is that in any modern city, GPS traces recorded by a GPS tracker are going to be very very inaccurate. When they are indoors or underground, most of the time there wont be any location data, with the occasional sudden apperance of a blit here a dot there, this results in wildly jagged traces all over the place (caused by multipath, which is the main problem with cheap GPS antennas, or antennas not pointed up. A qudrifilar helix is the best kind of antenna for this kind of situation. Its significantly better in rejecting multipath and funtioning when not oriented straight up..) .

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 14, 2020, 11:17:30 pm
content: Quote from: julianhigginson on May 14, 2020, 12:28:47 pmNo solution can be perfect, that is not the question. The question is more or less if the advantages outweigh the current method of isolating cohorts based on location/occupation or if this additional intermediate step introduces a false sense of security for users and delays things, given the disadvantages it has. The contact tracing is done at the very beginning to isolate an outbreak, but once this stage is over whole groups of people need to isolate themselves (lockdown). Surely people want to go back to normal after the first wave passed and then it might be back to the stage of contact tracing.Besides the problems with RF based distance measurement, there still is a whole set of other practical problems, e.g. leaving the phone somewhere (charger) while taking a break, people without a smartphone, empty battery, airplane mode.. which makes it pointless to trust such a solution entirely and that means fallback to isolate cohorts anyway. That means to also isolate people that were never infected (which you only know after a quarantine), but you are on the safe side of things and it means same rules apply for everyone. I consider there would be quite some unrest when there is contradicting information provided by an incomplete source.

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 11:25:40 pm
content: Good luck, stay safe!

author: Buriedcode
author_rank: Super Contributor
timestamp: May 15, 2020, 12:35:52 am
content: Quote from: David Hess on May 14, 2020, 03:39:07 pmI thought it was open source?https://github.com/nhsx/COVID-19-app-iOS-BETA

author: Someone
author_rank: Super Contributor
timestamp: May 15, 2020, 01:10:44 am
content: Quote from: Buriedcode on May 15, 2020, 12:35:52 amEven if the users app is open source (and able to be built from source to verify thats whats actually installed etc), it is only a small part of the system.Since people don't seem to read the links here:QuoteCentral state actor holding the keys and the information. The app is a part of the whole system, and while the user app might be good on privacy for the particular things it does (lets make a generous assumption here) the rest of the system can be full of holes. So the government stands up and makes lots of noise about how secure and private the user app is, entirely honestly, distracting people from how the system actually works and the privacy issues it has.

author: cdev
author_rank: Super Contributor
timestamp: May 15, 2020, 01:14:22 am
content: Issue: Individuals are tracked by Google Analytics. #11https://github.com/nhsx/COVID-19-app-iOS-BETA/issues/11Describe the bugIndividuals are tracked by Google Analytics.When accessing the Privacy Policy tracking code is passed from the application to the covid19.nhs.uk website which is processed by Google Analytics. Data captured could be used to re-identify an individual.COVID-19-app-iOS-BETA/Sonar/Appearance/LogoStrapline.swiftLines 45 to 48 in 370a518@IBAction func infoTapped(_ sender: UIButton) {let url = URL(string: "https://covid19.nhs.uk/?utm_source=nhscovid19ios&utm_medium=mobileapp&utm_campaign=nhscovid19app&utm_content=statuspage")!UIApplication.shared.open(url)}Expected behaviourIndividuals are NOT tracked by Google Analytics

author: vk6zgo
author_rank: Super Contributor
timestamp: May 15, 2020, 04:17:29 am
content: My first thought when this App was mooted was that very low transmitted power levels can result in high received signal levels in a "direct line of sight" situation, so if the detection relied upon signal strength, there would be a lot of false positives.I then rejected that, saying to myself that I don't know enough about Blue tooth, & on second thoughts, maybe the two devices exchanged "handshakes", measured the time this took, & knowing the speed of light, calculated the distance between them.The problem with that is possibly latency in both devices is different, so adding another layer of possible error.But as I said, I know damn all about Bluetooth.I don't have a smartphone, just a dumb one, as I have a desktop PC & an IPad, & didn't see any sense in adding a "pretend computer" to that lot!

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 15, 2020, 05:10:20 am
content: Quote from: cdev on May 14, 2020, 04:03:06 pmI understand a fair bit... I worked for a nursecall manufacturer for a couple of years, a few years ago now... we spent a *lot* of time trying to work out how to add location to alarm events while keeping the users' pendants low power, in ways that didn't also leave room for massive invasions of privacy or allow for incorrect locations to be sent.That was a very hard problem, and AFAIK the work on that project is still ongoing (as a background kind of thing) years after I left.The thing is, you've stated the problem with infection risk yourself... looking at the infection cluster data we have so far, a person's infection risk is about a person's proximity to an infected person indoors for an extended time.... it's not actually about *where* you are, but *who* you are near for long periods of time.BLE beacon tech on a smartphone can give us that. To some degree.now hear me out.. Yes it's obvious and I understand that the beacon app going off RSSI can't tell if you're 1m away from someone with a stud wall between you, or 5m away in the same room... that's definitely a shortfall in what the technology offers... BUT you can still identify long term proximity events... what you do with that data - refining it into usable information - becomes a problem for the people doing the actual contact tracing..In other words the dumb open source BLE app isn't "the contact tracing", it's an important tool in a sustained and serious contact tracing effort.scenario one:1) I, an un-diagnosed plague bearing wretch, go to a restaurant.2) you go to the restaurant next door and get seated at a table right next to me, but on the other side of the wall3) our phones make beacon friends as we sit down for an hour and eat our respective meals.4) the next day I feel bad.5) the day after i feel worse, and get tested6) test comes back positive.7) I give my app's recorded beacon buddies to the contact tracer people, and give them a list as best as possible of everywhere I spend extended periods of time over the last few days before I got sick (thanks, google location history!)they find you in my list and contact you.9) they confirm where you were on the day our beacon friendship blossomed.10) they discover you weren't in the same space as me, and realise that you're probably not at risk.Scenario 2 - the diff edition:2) on this day cruel fate made you pick the same restaurant as me (I mean we're beacon buddies right, it's natural we would have the same tastes in pizza) and sit across the room, all socially distanced like we're not really beacon buddies. but we know different.10) they discover we were in the same room for an hour. so you get tested. AT the point where it's highly unlikely you would be contagious or sick. so you need a test too.11) you come back positive (I'm really sorry, buddy.... I.... I didn't know... I had no idea....)12) you've just been given the chance to save everyone you spend time with from a big chance of being infected. Also you've got the chance of commencing any available treatment right at the onset of infection rather than once you're very sick.TL;DR is:beacon app badpeople using beacon app intelligently good.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 15, 2020, 09:46:29 am
content: Quote from: Someone on May 15, 2020, 01:10:44 amIt is the same (type of) government that funds Solar Roadways-like applications... okay?Coming of age usually includes to find out how clueless many many people are (inside or especially outside their field of expertise), and that is the step conspiracy theorists never got over.

author: tszaboo
author_rank: Super Contributor
timestamp: May 15, 2020, 09:01:49 pm
content: Quote from: julianhigginson on May 14, 2020, 12:28:47 pmYeah, but this is a virus. It doesnt work like radioactivity or as a aura around people. That 1.5m rule they say everywhere is better than nothing but it is not even close to modeling all the transmission methods. You can spend probably hours within 1.5m from someone, and turn up fine, if you are facing the opposite way. On the other hand if someone sneezes at you from 10m, you might get what they have. Or you touch a door knob, that someone infected touched a day ago.Or they grab a bottle of milk, that you buy, put in the fridge, the virus goes to sleep mode, and reactivate itself two weeks later.So I guess bluetooth should track these as well.There is a way for mobile phones to help in this situation. Build in an infrared temperature meter, to quickly measure forehead temperature.

author: cdev
author_rank: Super Contributor
timestamp: May 15, 2020, 09:17:26 pm
content: I am going to go out on a limb here and say that the worst, by far situation for a city dweller is public transportation. Everywhere else I am in the city, I have some modicum of controi, I can choose to walk way on the dege of the sidewalk or even step off the curve and walk in the street (against the traffic so I can see it coming) But the one place where people cant prevent being right next to people is in the subway or to a lesser extent on busses.The only technology that works for telling where people actually are in that setting is high resolution CCTV.I think this Bluetooth effort is destined to be unsuccessful for the reasons they said.By the way, people should be aware how often various surveillance devices are being used now in public places. If you are wondering, its easy to show how often transponder type devices like "EZ-Pass" are queried. These devices arent just where tolls are collected, they are everywhere. License plate readers and most likely devices that log Bluetooth Mac addresses too.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 15, 2020, 11:52:34 pm
content: @cdev : The UK goverment has overcome this problem by telling it's citizens to return to work AND to avoid using public transport. Easy... if you can afford to pay the parking fines which are still being enforced.With regard to the BLE tracking apps, I would like to know just how many concurrent connections a BLE app can handle. I know the manual says upto 20, but in the real world with everyone milling about like zombies in face masks?

author: SilverSolder
author_rank: Super Contributor
timestamp: May 16, 2020, 12:00:04 am
content: Quote from: Syntax Error on May 15, 2020, 11:52:34 pmBLE is an unstable mess, IME. I worked on a project once that used BLE to communicate with some hardware... every version of the OS behaved slightly differently, connections were randomly dropped and reappeared, etc. etc. - it all fueled the deep hatred for everything Bluetooth that I still harbour today!

author: cdev
author_rank: Super Contributor
timestamp: May 16, 2020, 01:25:11 am
content: A couple of years ago I went around to all my computers and physically disabled the bluetooth on my own computers. But I didn't remember the exact reason why until a search here jogged my memory..https://www.eevblog.com/forum/microcontrollers/major-bluetooth-security-issue-blueborne/msg1300894/#msg1300894Bluetoooth has serious security flaws that seem to be able to result in attackers being able to completely pwn a machine..https://www.bleepingcomputer.com/news/security/blueborne-vulnerabilities-impact-over-5-billion-bluetooth-enabled-devices/This article claims that 5 BILLION devices are vulnerable. Basically all bluetooth devices.This is why I literally almost never use it anymore. To the point of having taken steps to disable it so it literally cant be turned on. On older hardware (all of my hardware, basically, at that point, and I have not bought new) that they refuse to fix, the security issue seems to be that bad.Quote from: SilverSolder on May 16, 2020, 12:00:04 amIt's a security nightmare.This quote is from 2017Quote from: jnz on September 19, 2017, 03:57:04 pm

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2020, 10:58:43 am
content: We also need good old fashioned contact tracing, which involves manually finding those who've had close contact with an infected person, testing them and isolating them if they're positive. The app might be able to help with that, but it's not a magic bullet.

author: cdev
author_rank: Super Contributor
timestamp: May 16, 2020, 02:08:56 pm
content: I don't know about the situation in the UK, but it seems likely to be similar to here.TRUMP - 'When you test, you have a case. When you test, you find something is wrong with people. If we didn't do any testing we would have very few cases'.See it in context:https://twitter.com/atrupar/status/1261017121078861826

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2020, 04:19:40 pm
content: Quote from: cdev on May 16, 2020, 02:08:56 pmI honestly don't want to get into politics.I hope the authorities in the US are ignoring everything Trump says about COVID-19.China is currently doing very well to control the outbreaks through testing and contact tracing, even though most of the social distancing measures have been scrapped. They're testing 1 million per day in Wuhan, over ten times the entire UK.I believe the UK government want to increase testing and contact tracing, so the lockdown can be gradually eased, without a massive increase in cases. Unfortunately I doubt the infection rate has reduced to a level which can be controlled by the current testing and contact tracing capacity. Hopefully the current R0is well below 1 and the tiny increase due to the recent slight relaxation will not raise it above 1 before testing and contract tracing capacity catches up.I think contact tracing could be more important than testing in bringing the R0down, without a lockdown. If those who have had close contact with someone who's shown COVID-19 symptoms, can be traced and isolated for at least 7 days, it should mitigate most of the spread. The contact tracer will judge who needs to isolate and who doesn't, based on risk factors such as the closeness and duration of the contact. For example if I develop a fever and have recently visited my nephews, aged 6 and 8, the whole family will probably have to self-isolate, where as one of my colleagues, who I don't work that closely with, might not have to. Testing would be good to cut down on the numbers who are unnecessarily isolating, but we should be able to drastically reduce the spread without testing lots of people, or isolating everyone, just by contact tracing.

author: David Hess
author_rank: Super Contributor
timestamp: May 16, 2020, 05:50:24 pm
content: Quote from: Zero999 on May 16, 2020, 04:19:40 pmChina *says* that but given how duplicitous they have been and the independent reports which contradict them, why should they be believed?

author: cdev
author_rank: Super Contributor
timestamp: May 16, 2020, 06:30:11 pm
content: Quote from: Zero999 on May 16, 2020, 04:19:40 pmIt's labor intensive when you have screwed up at the beginning as we have. If you look at the US, subtracting the area that I am in, where the new infections are falling, its still rising quite a bit.The only reason the graph for the US seems to have leveled off is the NY Metro Area reductions. So it is entirely bad policy to relax restrictions now.So we here in the US cant say we leveled the curve because we haven't. I bet the same thing applies to the UK. I saw pictures of people riding the London Underground and buses without masks, lots of people crammed in. A number of other countries relaxed restrictions and new cases started to soar again, so that has turned out to have been a mistake for them. Lots and lots of new cases, fast.There is no reason to think it would be any different in the UK or US.

author: Marco
author_rank: Super Contributor
timestamp: May 16, 2020, 06:32:40 pm
content: Quote from: cdev on May 16, 2020, 06:30:11 pmI think most countries have decided to accept Swedish infection/death rates so they can have an economically feasible level of distancing and containment measures are just window dressing.

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2020, 07:56:18 pm
content: Quote from: David Hess on May 16, 2020, 05:50:24 pmTrue, but there doesn't seem to be any evidence they're lying either. They aren't any signs that it's getting out of control such as hospitals packed full of COVID-19 patients, or bodies piling up, like they were before.The Chinese are used to this. They've done it before and once the government finally realised it was a problem they seem to have being dealing with it quite well. It's highly likely the higher levels of the government weren't aware of it, at the start when the local authorities were trying to hide it. The fact the authorities know exactly where the current coronavirus clusters are, indicates they've been testing and are able to deal with them.I know China gets bashed a lot by westerners and often quite rightly so, but I believe they're more able to deal with this more effectively than most western governments.Quote from: cdev on May 16, 2020, 06:30:11 pmYes contact tracing is a lot of hard work but it's certainly more cost effective and easier than the alternatives.I agree it's a bad policy to reduce restrictions without any clear plan of how to prevent a second wave.If we don't have sufficient testing capacity one possible solution is test pooling. A large number of samples are taken, some of each pooled together and tested. Each sample only needs to be tested, if the pool tests positive, thus cutting the number of tests required.https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30362-5/fulltext

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 17, 2020, 12:02:02 am
content: Quote from: David Hess on May 16, 2020, 05:50:24 pmThey don't want their people to die and having to bear the associated political implications?

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 17, 2020, 12:27:20 am
content: Quote from: SparkyFX on May 17, 2020, 12:02:02 amTiananmen Square 1989

author: David Hess
author_rank: Super Contributor
timestamp: May 17, 2020, 12:57:03 am
content: Quote from: Zero999 on May 16, 2020, 07:56:18 pmEvidence from doctors and journalists who China has been persecuting for revealing what has been happening? Who is left to report?Quote from: SparkyFX on May 17, 2020, 12:02:02 amThat is a laugh. Their only political considerations are maintaining order (suppressing unrest) and maintaining their reputation with other nations. The next best thing to controlling an epidemic is advertising that you are.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 17, 2020, 03:19:26 am
content: Quote from: Syntax Error on May 17, 2020, 12:27:20 amstudents protesting for changes in the government != all sorts of people (including party members) die from an illnessI reckon there is no secret second source of information and they can not afford to misinform themselves about this one. A virus simply makes no distinction what the infected person believes. Especially as China can benefit from international support, therefore involvement of the WHO and them keeping track of developments. Politicizing science is usually a bad idea - as well as media hyping it (to some extent),Quote from: David Hess on May 17, 2020, 12:57:03 amOne mans suppression of unrest is another mans way to work in the sense of a greater good. Not every unrest is a good thing/has a positive outcome, or would make sense in case of a pandemic... you can't protest a virus. I think we agree that the methods they used make a difference to western countries, but well, this is how China operates and they won't change that overnight. Sure this is all up to interpretation, i think that initially some authorities were trying to address the spread of unconfirmed information to avoid a panic while this unfolded. This is one of those cases in which a bureaucracy was faced with something for which no way of confirming it existed, which leads to wrong decisions.Which brings us back to the topic, if Bluetooth devices are suitable to do contact tracing or if it is just a hastily propagated pseudo-solution. There are other ways to leverage the benefits of the information age, that might have bigger impact, like digital transfer of documents, test status and so on to help people get along, but also have a potential for abuse or privacy issues.

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 17, 2020, 06:42:14 am
content: Quote from: NANDBlog on May 15, 2020, 09:01:49 pmMy point is that something DOES NOT have to be perfect or work in 100% of cases to still be valuable.At the end of the day it's not specific performance of the tool in specific individual cases, but if rolled out over a population it allows R0 to be brought down lower than it would be otherwise.If all it turns out to do is create a bunch of bad possible transmission links that prove to be a waste of time to the tracing effort, then sure, stop using it.. but that would want to be borne out of real data.... My expectation is that because it's capturing links to people you have been near for extended periods of time, it could be very useful.

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 17, 2020, 07:01:42 am
content: Quote from: cdev on May 16, 2020, 01:25:11 amBlueborne is old news. Do you think anything new still has these vulnerabilities at a level that will cause practical risk to an everyday user?If anything, it's just one more reason to make sure hardware manufacturers need to be forced to build critical security issue update support into their prices.https://duo.com/decipher/an-analysis-of-blueborne-bluetooth-security-risksI really don't see blueborne as any kind of modern reason to leave bluetooth turned off these days unless you have a very specific reason to do so. In fact the only time I ever hear of it these days is when my old music scene friend from years ago keeps banging on about it on facebook as a reason why all wireless communications is faulty spyware and 5G needs to be stopped.And unfortunately, pretty much anything to do with any device running a general purpose OS is a security nightmare.Check out what was just discovered about thunderbolt (fundamental issue for at least all of the TB1-3 interfaces) if you want scary.Any computer with a thunderbolt port turned on is now up for evil maid attacks.And there's no bios fix to be had, it's a fundamental fault with the direct RAM access that a fast port like this needs to be able to workhttps://thenextweb.com/security/2020/05/11/theres-a-new-thunderbolt-bug-check-if-your-computer-is-affected/or look at the latest issues around iOS exploits - exploit vendors have stopped offering $ for them for now, as they have too many.https://www.theregister.co.uk/2020/05/14/zerodium_ios_flaws/

author: Zero999
author_rank: Super Contributor
timestamp: May 17, 2020, 08:46:35 am
content: Quote from: David Hess on May 17, 2020, 12:57:03 amWe're not talking about an individual, like a child who you won't believe because they lied about doing something naughty, but they say they're honestly telling the truth this time, so you should believe them. All governments are multilayered. It's possible the local authorities covered it up and the national government were ignorant at the start of the crisis, but when they found out they dealt with it. This is like a teacher not telling the head about a group of pupils' bad behaviour, because the fear they'll get into trouble for not being able to deal with them, but once the head found out there were behavioural problems in the class, they dealt with the culprits and are keeping an eye out for any troublemakers who slipped through the net.China has changed a lot since the last 40 years. It's not a democracy, but it's no longer a completely closed society. Information leaks out of the country, whether the government likes it or not. If the coronavirus situation is getting out of control again then there would be plenty of reports about it, as there were before, in spite of the cover up. The fact that this time the Chinese have admitted that there are new outbreaks of COVID-19, rather than covering it up as they did previously, suggests they're not lying about it now.Quote from: julianhigginson on May 17, 2020, 06:42:14 amYes, that is what I've being saying all a long. Contact tracing isn't new. It existed long before smartphones and has other applications than controlling infectious diseases. If there's an outbreak of food poisoning then contact tracing is one of the tools used used to find the source, such as a rat infested restaurant or a supermarket selling out of date food. The app is just another tool in addition to the usual detective work.Hopefully the authorities were investing heavily in manual contract tracing, not just the app, but training thousands of people to do it, whilst the economy was put into an induced coma. If controls are relaxed before there's sufficient capacity to control the infection, then it'll just flare up again. Some countries are doing better than others, which is partly down to geographical factors, as well as the competence of the governments. More isolated countries, who locked down earlier in their epidemics will stand a higher chance of a better outcomes, than those who are international hubs.

author: cdev
author_rank: Super Contributor
timestamp: May 17, 2020, 07:54:14 pm
content: All of my hardware is pre 2017 hardware - which isnt that old, is still so old the manufacturers who wants to sell new hardware didn't upgrade its FIRMWARE, instead saying that EOL hardware wont be fixed. So BT got turned off and it stays off. Only Linux hardware has been kept current. I had the freedom to turn off Bluetooth in all my devices, so I have.Why don't they use high res CCTV inside of subways/busses? Thats really the only way to do what they want that has any chance of being even remotely accurate.Quote from: julianhigginson on May 17, 2020, 07:01:42 am

author: cdev
author_rank: Super Contributor
timestamp: May 17, 2020, 08:03:59 pm
content: Are they actually contract tracing?An inaccurate Blutooth App is actually a good way to guarantee that their staff is flooded with inaccurate, noisy information probably guaranteeing they dont have time to do the real contact tracing that might be called for.If they took high resolution CCTV of all those places where people are crammed together, that would be helpful. Also they should only allow as many people on busses and subway cars as can stand safety some modest distance away from others not talking while trying to breath shallowly. Otherwise, as somebody who has commuted a very large chunk of my life, its just impossible.Worst was when the World Cup was being held right near my workplace.

author: Zero999
author_rank: Super Contributor
timestamp: May 17, 2020, 10:03:10 pm
content: I hope they are contact tracing. Yes CCTV is a good idea, perhaps using automatic image recognition could help, although that could cause privacy concerns. Not everywhere has CCTV though.Another possibility is making people show ID before they go onto a bus or train where social distancing is difficult, then they can be contact traced if someone sitting close to them tests positive.Looking into this more, I don't think contact tracing alone will be enough to control the virus. There will still need to be significant social distancing in place until we either have a vaccine or sufficient herd immunity gradually develops naturally. It's just too easily spread via asymptomatic carriers to trace everyone. There will be perodic flare-ups followed by containment via lockdowns. Contact tracing will just help to find the flare-ups so the lockdowns can be more localised.

author: cdev
author_rank: Super Contributor
timestamp: May 18, 2020, 12:52:07 am
content: The risk of catching the virus is very low outdoors.https://www.nytimes.com/2020/05/15/us/coronavirus-what-to-do-outside.htmlIts thousands of times higher indoors.But GPS does not work indoors and Bluetooth both doesnt work for determining location or distance, and its a security + privacy nightmare. Also old hardware wont be upgraded so those problems are baked in.

author: Zero999
author_rank: Super Contributor
timestamp: May 18, 2020, 10:22:50 pm
content: Quote from: cdev on May 18, 2020, 12:52:07 amYes it's true the risk of catching the virus outdoors is low and is why many countries have loosened the rules governing outdoor activity such as allowing fishing and golf clubs to open, providing certain conditions are met.GPS doesn't have to work indoors to be effective. Knowing that an infected person visited a certain premises or took a bus, within the last 7 days is all that's needed most of the time. It's true it's not effective in underground situations such as the Tube, but there are plenty of other instances when it will work, such as catching a bus or walking from the car, across the car park to a supermarket.Bluetooth doesn't have to accurately determine distance. The user just needs to know it's likely they've been in the vicinity of an infected person, so should self-isolate and preferably get tested. As long as the virus is at a manageable level, it won't even matter that much if it generates a relatively large number of false positives, there will still far fewer people stuck at home, than there would be in a lockdown. It doesn't matter if not everyone uses it, as long as on average, it prevents one person infecting someone else.We're not epidemiologists and I doubt the developers are either, so we can't form reliable opinions on how well or not it will work in real life. It's definitely worth a try. Any intervention in disease control has costs and risks, which is why extensive in-field testing is required to determine whether they're worth the benefits.

author: cdev
author_rank: Super Contributor
timestamp: May 19, 2020, 01:59:46 am
content: Where its accurate, the risk of infection is almost zero.Where its inaccuate, or unavailable, the risk of infection is high. That doesn't make sense to me, does it to you?

author: julianhigginson
author_rank: Frequent Contributor
timestamp: May 19, 2020, 07:47:35 am
content: well, here's the biggest argument against the app in Australia that I've seen so far.I'm keeping it on my phone for now, but not sure how much longer if they can't manage to integrate the data with the rest of the contact tracing system they have...https://www.theguardian.com/australia-news/2020/may/19/nsw-and-victoria-are-unable-to-use-covidsafe-apps-data-for-contact-tracing

author: SilverSolder
author_rank: Super Contributor
timestamp: May 19, 2020, 02:30:35 pm
content: Quote from: julianhigginson on May 19, 2020, 07:47:35 am"Digital Transformation Agency" LOL

author: SparkyFX
author_rank: Frequent Contributor
timestamp: May 19, 2020, 05:12:11 pm
content: Quote from: Zero999 on May 18, 2020, 10:22:50 pmThat's for sure, it could add to the set of tools for contact tracing, but imho never replace it, because the false positives might be so widespread that you immediatly go to lockdown anyway or the threshold is set so high that too many cases are under the radar and you get an outbreak.It surely helps in cases like where you can't name the person you sat next to in public transport, trying to identify all riders is next to impossible.

author: tom66
author_rank: Super Contributor
timestamp: May 19, 2020, 05:27:44 pm
content: Quote from: jogri on May 11, 2020, 02:54:32 pmGPS doesn't work indoors, underground, or even sometimes if the device is in a less than favourable orientation. Plus, there are considerable privacy implications: you are now giving the government full positional data on all citizens. Will they give that up?The present system using BLE assumes that infection occurs if you spend more than X minutes around a given individual. For instance, while queueing at a shop. While not perfect, it reduces a lot of concerns around privacy because it can be based on entirely anonymous keys.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 19, 2020, 05:40:53 pm
content: Here in the UK we are recruiting 14,000 contact tracers. So far, a week before the BLE app launches, we have about 900 - mostly in managerial roles. From a real world job advert, this is the kind of plug and play team player that they are seeking to employ part-time...Someone who has... Experience of working in telephone or face to face customer services. Is passionate about exceeding customers expectations and delivering an outstanding customer experience. A great communicator, both written and verbal, who wakes up every day wanting to exceed client and customer expectations. Strong desire to learn, take on board feedback, strive to improve and work to personal goals as well as part of a driven, energetic team!And also knows f'all about Covid-19.

author: Marco
author_rank: Super Contributor
timestamp: May 19, 2020, 07:10:47 pm
content: Quote from: tom66 on May 19, 2020, 05:27:44 pmAssuming it works, false positive/negative rates in complex environments with lots of steel around (ie. supermarkets) are an open question AFAICS.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 19, 2020, 08:30:37 pm
content: Quote from: Marco on May 19, 2020, 07:10:47 pmWhich is why several posters here, as well as the devs themselves have commented just that. It's less than ideal, will require some testing - or rather testing it in the wild before making any kind of major decisions based on its results. There is the danger of the government relying too much on this, but it seems the UK hasn't done too badly in their response in terms of listening to their experts, so I can only assume/hope that the results will be taken wit a pinch of salt, at least until its relative efficacy is known.I get the impression that some here believe such apps are seen by others as techno salvation, possibly based on the sensationalist media, but I don't know anyone who believes such an app will be a magic bullet.

author: nctnico
author_rank: Super Contributor
timestamp: May 19, 2020, 08:40:47 pm
content: The Dutch government has become awfully quiet about a tracking app. The new mantra is testing testing testing and manual contact tracing.

author: Zero999
author_rank: Super Contributor
timestamp: May 19, 2020, 10:33:43 pm
content: Quote from: cdev on May 19, 2020, 01:59:46 amIt depends on how it's inaccurate. Yes, if it doesn't generate enough positives, when it should, then it will allow the infection to spread too much and be useless, but if it errs on the side of caution and generates more positives, than necessary, then it will reduce the rate of infection. If everyone on the same train carriage goes into self-isolation for a week, because one person had it, then any of them who have caught it won't infect anyone else and it would have done its job.And you've completely missed the point that just because GPS is unavailable in some buildings it doesn't make it useless. If some people are at a bus stop, then disappear off the radar, only to reappear somewhere else, a few miles down the road, they've obviously been on the bus together and if one of them is infected, then the others should self-isolate for a week. It doesn't take much imagination to see how this could be effective for tracking people to other indoor spaces.Quote from: SparkyFX on May 19, 2020, 05:12:11 pmI agree, there needs to be some manual intervention for it to work well. Even if GPS isn't used to track the person continuously, position data could be stored on the users phone and only uploaded when they test positive, with their consent and the condition that it's deleted within a week. For maximum transparency it could be in plain text format. Heck GPS might even be useful if it's only stored locally and never uploaded. It can help the user who's had a hit decide whether they need to self-isolate and get tested or not.Testing will help to reduce the number of people self-isolating due to false positives, but simply asking someone questions can cut down on the number of wasted tests. For example, I cycle to work and being outdoors it's unlikely I'll infect anyone, or pick up it up off anyone else, so if my phone were to get a hit during my journey to work, there's little point in being tested or self-isolating. If the person who's infected is on a bus which overtakes me and I get the hit, then it's impossible for them to infect me, but possible other people on the bus could have caught it. All it would take is for someone to ask me if I ride the bus at that time of day to eliminate me.

author: tom66
author_rank: Super Contributor
timestamp: May 20, 2020, 07:58:01 am
content: Well, the good news is the contract tracers will all know each other, at least in the UK.https://www.bbc.co.uk/news/uk-52732818Seriously, do people still not understand Bcc vs Cc?

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 20, 2020, 08:39:24 am
content: Here in the UK, public sector service provider Serco does not exactly enjoy the best reputation when it comes to IT security. As one of the UK goverment's go-to cheapest is best providers, it's more 'Ryan Air' than 'Emirates'. So employing a 'high flyer' who doesn't know how to send an email, is no real surprise. Knowing that Serco is in the supply chain for UK contact tracing leaves me to consider, should the app be avoided?

author: nctnico
author_rank: Super Contributor
timestamp: May 20, 2020, 10:29:54 am
content: Quote from: Zero999 on May 19, 2020, 10:33:43 pmGPS is useless for tracking. The inaccuracy in a city can easely be +/-80m (if not more with high buildings around). A much better option is to use triangulation between cell towers.

author: Zero999
author_rank: Super Contributor
timestamp: May 20, 2020, 12:36:54 pm
content: Quote from: nctnico on May 20, 2020, 10:29:54 amThat must be a worst case scenario. I've found satellite navigation systems to be much more accurate than that and we don't need 2m accuracy, just whether two people are in the same building or not will do. It can be combined with other data such as maps to narrow it down further. If triangulation is better, then use that too.Irrespective, combining it with manual contract tracing will help a lot. Even 1 km accuracy would be better than nothing at all.Quote from: tom66 on May 20, 2020, 07:58:01 amI can't believe anyone would be that dumb.

author: cdev
author_rank: Super Contributor
timestamp: May 20, 2020, 03:49:27 pm
content: City, as in big city, and country driving are two totally different situations..They are testing the situation on the Isle of Wright. Thats a location that seems likely to me to have almost an ideal situation for GPS. Probably very few if any tall buildings or underground areas, and even the largest buildings seem likely to be as large as the smallest buildings in most big cities.Many people who dont live in big cities never go driving in them. So their own GPS which looks and is accurate enough to spot lane changes under local use seems accurate enough to them.But its an entirely different situation in cities with lots of tall steel buildings, (urban canyons) or inside a network of streets where traffic often descends underground to get from point A to point B.Newer phones can and sometimes are more accurate but there are hard limits to the coverage -Outdoors, coverage is fairly good, but accuracy declines greatly in dense cities,exactly where people are forced more closely together.(Risk of infection is by all accounts very low outdoors)1. whether a fix is available or not largely comes down to whether somebody is outdoors or indoors.2. in the places where people would be most likely to pick up infections, (indoors) it is basically guaranteedto either be unavailable or very very inaccurate and unpredictable.Nonetheless, ifthissystem was available, it would invariably be used more than its accuracy would dictate it should be.Does anybody remember the report that came out several years ago from the UK government on the safety of cell phones? That was a good example, of a badly done investigation of a subject that clearly had only one decision in mind and was determined to block off any adult discussion of the unknowns.Quote from: nctnico on May 20, 2020, 10:29:54 amThats what TruePosition used to do but a few years ago they were pushed out by some other folks and I dont know if it emerged why or not.

author: nctnico
author_rank: Super Contributor
timestamp: May 20, 2020, 05:26:51 pm
content: Quote from: Zero999 on May 20, 2020, 12:36:54 pmNavigation systems rely heavily on mapping your movements on a map and only use GPS as a hint to where you are. If you look at the raw GPS data you'll see it can be total garbage in urban areas. Just take a different turn then your navigation system is pointing to. You'll see it will have trouble catching up.