Comments on: Purnell’s Lie Detector – The Scientific Evidence http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/ Voilà! In view, a humble vaudevillian veteran, cast vicariously as both victim and villain by the vicissitudes of Fate. This visage, no mere veneer of vanity, is a vestige of the vox populi, now vacant, vanished. However, this valorous visitation of a by-gone vexation, stands vivified and has vowed to vanquish these venal and virulent vermin van-guarding vice and vouchsafing the violently vicious and voracious violation of volition. Tue, 09 Mar 2010 12:28:22 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Robert http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/comment-page-1/#comment-27517 Robert Thu, 11 Jun 2009 08:00:52 +0000 http://www.ministryoftruth.me.uk/?p=2120#comment-27517 If your disabled , I think everyone I know are stressed out anyway, and if you have had dealings with the DWP you'd be stressed out even if your disabled or cheating the system.<div class="comment-remix-meta"><a href="#" class="replyto" onclick="replyto('27517','Robert'); return false;">Reply</a> | <a href="#" class="quote" onclick="quote('27517','Robert','If your disabled , I think everyone I know are stressed out anyway, and if you have had dealings with the DWP you\'d be stressed out even if your disabled or cheating the system.'); return false;">Quote</a></div> If your disabled , I think everyone I know are stressed out anyway, and if you have had dealings with the DWP you’d be stressed out even if your disabled or cheating the system.
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]]> By: sanbikinoraion http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/comment-page-1/#comment-27430 sanbikinoraion Thu, 19 Mar 2009 23:45:41 +0000 http://www.ministryoftruth.me.uk/?p=2120#comment-27430 Fair enough, I didn't realize that PSTN used that little bandwidth. However, to say that it would generate 'more' digitization artefects is a little disingenuous, isn't it? Because with a high sample rate you'll actually be sampling the waveform more accurately and therefore be able to filter out a lot more of them as either so large that they are an outlier or so small that they are probably a sampling artefact. Not that any of this matters - while it is perhaps possible to build a theoretically-better system than the one they have built, it alters not a jot how good their system actually is right now :)<div class="comment-remix-meta"><a href="#" class="replyto" onclick="replyto('27430','sanbikinoraion'); return false;">Reply</a> | <a href="#" class="quote" onclick="quote('27430','sanbikinoraion','Fair enough, I didn\'t realize that PSTN used that little bandwidth. However, to say that it would generate \'more\' digitization artefects is a little disingenuous, isn\'t it? Because with a high sample rate you\'ll actually be sampling the waveform more accurately and therefore be able to filter out a lot more of them as either so large that they are an outlier or so small that they are probably a sampling artefact.\r\n\r\nNot that any of this matters - while it is perhaps possible to build a theoretically-better system than the one they have built, it alters not a jot how good their system actually is right now :)'); return false;">Quote</a></div> Fair enough, I didn’t realize that PSTN used that little bandwidth. However, to say that it would generate ‘more’ digitization artefects is a little disingenuous, isn’t it? Because with a high sample rate you’ll actually be sampling the waveform more accurately and therefore be able to filter out a lot more of them as either so large that they are an outlier or so small that they are probably a sampling artefact.

Not that any of this matters – while it is perhaps possible to build a theoretically-better system than the one they have built, it alters not a jot how good their system actually is right now :)

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]]> By: quack quack oops « Alternate Seat of TYR http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/comment-page-1/#comment-27423 quack quack oops « Alternate Seat of TYR Sun, 15 Mar 2009 15:18:10 +0000 http://www.ministryoftruth.me.uk/?p=2120#comment-27423 [...] March 15, 2009 in hacker, protest, quackery, stupid procurement, surveillance The Guardian leaps in on the Nemesysco lie-detector crapware story, and misses; notably, they are apparently too chicken to point out that they are claiming to get 129 dimensions of data from only two actual measurements. This wouldn’t even involve the Lacerda/Eriksson paper; it would just involve reading their published statements and the content of the patent they filed. There is, as usual, almost too much more at the Ministry. [...]<div class="comment-remix-meta"><a href="#" class="replyto" onclick="replyto('27423','quack quack oops « Alternate Seat of TYR'); return false;">Reply</a> | <a href="#" class="quote" onclick="quote('27423','quack quack oops « Alternate Seat of TYR','[...] March 15, 2009 in hacker, protest, quackery, stupid procurement, surveillance The Guardian leaps in on the Nemesysco lie-detector crapware story, and misses; notably, they are apparently too chicken to point out that they are claiming to get 129 dimensions of data from only two actual measurements. This wouldn’t even involve the Lacerda\/Eriksson paper; it would just involve reading their published statements and the content of the patent they filed. There is, as usual, almost too much more at the Ministry. [...]'); return false;">Quote</a></div> [...] March 15, 2009 in hacker, protest, quackery, stupid procurement, surveillance The Guardian leaps in on the Nemesysco lie-detector crapware story, and misses; notably, they are apparently too chicken to point out that they are claiming to get 129 dimensions of data from only two actual measurements. This wouldn’t even involve the Lacerda/Eriksson paper; it would just involve reading their published statements and the content of the patent they filed. There is, as usual, almost too much more at the Ministry. [...]
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]]> By: Unity http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/comment-page-1/#comment-27422 Unity Fri, 13 Mar 2009 14:48:06 +0000 http://www.ministryoftruth.me.uk/?p=2120#comment-27422 That might sound reasonable as it would, theoretically, cut out much of the noise in the system but, in reality, it would only make things worse because upping the sample rate increases the number of digitisation artefacts and therefore the output scores of the system. The other problem of course is that it wouldn't make much difference to the quality of the sound signal because the system takes its input from the public telephone system, which operates at only 8KHz. In effect, resampling a telephone signal to take it up to 44KHz is like taking a 100x100 pixel image and blowing it up, using Photoshop, to something like 600x600 pixels - you might bigger image but its still going to heavily pixellated because of the lack of detail in the original image.<div class="comment-remix-meta"><a href="#" class="replyto" onclick="replyto('27422','Unity'); return false;">Reply</a> | <a href="#" class="quote" onclick="quote('27422','Unity','That might sound reasonable as it would, theoretically, cut out much of the noise in the system but, in reality, it would only make things worse because upping the sample rate increases the number of digitisation artefacts and therefore the output scores of the system.\r\n\r\nThe other problem of course is that it wouldn\'t make much difference to the quality of the sound signal because the system takes its input from the public telephone system, which operates at only 8KHz.\r\n\r\nIn effect, resampling a telephone signal to take it up to 44KHz is like taking a 100x100 pixel image and blowing it up, using Photoshop, to something like 600x600 pixels - you might bigger image but its still going to heavily pixellated because of the lack of detail in the original image.'); return false;">Quote</a></div> That might sound reasonable as it would, theoretically, cut out much of the noise in the system but, in reality, it would only make things worse because upping the sample rate increases the number of digitisation artefacts and therefore the output scores of the system.

The other problem of course is that it wouldn’t make much difference to the quality of the sound signal because the system takes its input from the public telephone system, which operates at only 8KHz.

In effect, resampling a telephone signal to take it up to 44KHz is like taking a 100×100 pixel image and blowing it up, using Photoshop, to something like 600×600 pixels – you might bigger image but its still going to heavily pixellated because of the lack of detail in the original image.

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]]> By: sanbikinoraion http://www.ministryoftruth.me.uk/2009/03/13/purnells-lie-detector-the-scientific-evidence/comment-page-1/#comment-27421 sanbikinoraion Fri, 13 Mar 2009 12:31:53 +0000 http://www.ministryoftruth.me.uk/?p=2120#comment-27421 I don't know, and presumably you've checked this out, but it would be nice if you could assuage my concerns on this (and it's probably irrelevant but possibly worth stating anyway): Couldn't a "software update" increase the rate that the incoming sound is sampled at? If a later software version samples at eg. 44Khz, that would surely ameliorate some of the problems with the analogue-to-digital conversion? I'm not saying that it would have any effect on the efficacy of the system, but it seems like upping the sample rate would be something that's very easy to do.<div class="comment-remix-meta"><a href="#" class="replyto" onclick="replyto('27421','sanbikinoraion'); return false;">Reply</a> | <a href="#" class="quote" onclick="quote('27421','sanbikinoraion','I don\'t know, and presumably you\'ve checked this out, but it would be nice if you could assuage my concerns on this (and it\'s probably irrelevant but possibly worth stating anyway):\r\n\r\nCouldn\'t a \"software update\" increase the rate that the incoming sound is sampled at? If a later software version samples at eg. 44Khz, that would surely ameliorate some of the problems with the analogue-to-digital conversion? I\'m not saying that it would have any effect on the efficacy of the system, but it seems like upping the sample rate would be something that\'s very easy to do.'); return false;">Quote</a></div> I don’t know, and presumably you’ve checked this out, but it would be nice if you could assuage my concerns on this (and it’s probably irrelevant but possibly worth stating anyway):

Couldn’t a “software update” increase the rate that the incoming sound is sampled at? If a later software version samples at eg. 44Khz, that would surely ameliorate some of the problems with the analogue-to-digital conversion? I’m not saying that it would have any effect on the efficacy of the system, but it seems like upping the sample rate would be something that’s very easy to do.

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