Afraid so... (advanced-degree'd hardware design engineer, 20+ years in mil/aero custom switching power supply design).
The half-sine you are drawing is the current into a resistive load. The second waveform is more consistent with rectification into a very large energy-storage cap - like those typically placed on the input stage of a switcher.
What you're observing is the classic (and typical) full-wave-rectified-and-pumped-into-a-capacitor current waveform of an un-PF-corrected power supply. The waveform has an inherent PF of about 50-60% (if I recall correctly - its been a while) or thereabouts - depending on parametric details. So any input power calculation based on simple RMS measurements could be off (high) by 40-50%. Thus...a 1KW measurement instead of (perhaps) 500-600W input. Correction would yield a conversion efficiency in the high 60's (still low) or low 80's (about right). Bottom line: IMHO something's seriously wrong with the measurement/data given.
The Slashdot effect is in full force so I can't RTFA, but given the 1KW in / 400W out description, I would venture to guess that either someone didn't measure or account for power factor on the input current waveform, or the thing was significantly glowing prior to smoke-release. 40% efficiency at that power level - ahem - sucks mightily.
Google, engineers are expected to spend one day a week on a project of personal interest.
AT&T top management tried this in Dallas in the 90's until a manager took them at their word and enforced the 1/5 rule. The resultant loss in overall productivity quickly caught managements eye and the policy was quietly curtailed.
I suspect that the MSM will go the way print media has gone with the advent of TV and radio proliferation. Print media used to be THE only source; then broadcast media and radio took a lot of their market share. Likewise, I believe that blogs - in a future format perhaps - will significantly overwhelm the MSM as news sources.
As has been posted in other comments, many, many blogs are little better than personal diaries - of no interest to most people. Of course most small, home-town newspapers are in the same boat. But the significant few blogs are beginning to make a greater and greater difference, especially in how the MSM does its reporting and fact-checking. They are also quite effective in calling-to-task the MSM over their many gaffes and outright lies (both by Commission and Ommision). The old paradigm that "the MSM is the only source" is being nibbled at bit by bit.
I feel that this is for the better - you can't have too many sources of info. It just makes sorting the wheat from the chaff a tiny bit harder.
Yep. Read it quite some time ago. Researched it on my own, starting with his references. Reviewed the bogus hockey-stick data. reviewed the "arguments" trying (and failing) to prop it up. Then I slowly picked up on the pattern of "assuming its there" that seemed to be inherent in the pro-G-W articles.
I'm quite sceptical about Global warming. Near as I can tell, the phenomenon (if it exists at all) is so buried within greater natural, well-understood cyclic climate variations that NO ONE has been able to show that G-W is even present.
But I didn't comment on the above article because I figured I'd be deluged with flame.
G-W is like religion; you'll never change anyone's mind by arguing the facts, because the facts (or lack thereof) aren't what's motivating them to insist that it exists. Its a matter of dogma and faith. And a dose of liberal feel-good self rightiousness.
Go ahead; mod me to -1; I got excellent karma and a good track record of 4's and 5's, so I really don't give a shit. I'm just killing time - waiting for my roast beef in the oven to get done for dinner.
I suspect that you may be confusing belief with religious faith. And - again - the conclusion that "...then Newton et al weren't any good at learning..." does not necessarily follow from RAH's homily.
"Heinlein is entertaining..."
Heinlein was ALWAYS in a dirty-old-man stage. for many years he and his (2nd) wife were active nudists, and had one of the earliest(?) open marriages. The social upheavals of the 60's simply allowed him a bit more literary freedom. But I digress: Why should I take what RAH says with a (implied) larger-than-average grain of salt simply because he was a DOM? Does DOM-hood preclude being intelligent or insightful?
Perhaps if you were better educated and less arrogant, you would realize that your assertion is not the only possibility that can be asserted from the data.
Perhaps the other 40% adhere to the principle that Belief gets in the way of learning.
Is this the kind of activity we should really be promoting?
You answered your own question in your first sentence: "This is just like real life."
Humans (and spec writers, too!) make mistakes and sometimes overlook aspects of a desired requirement that are important. Recognising this and being ready to deal with it is part of the job for any professional in any industry.
Since you were the first to most graciously post the article from the (so predictably) now-slashdotted server, you win.....(drum roll)....
ONE SIDE OF KAZAKHSTANI BOOSTER-SMACKED BEEF!
Yes good comrade...Kazakhstani beef. Not a substitute! This beef was slow-marinated in pure slavic hydrazine - no oxygen here! - after being gently but firmly caressed by a 13-ton booster moving at terminal velocity! Range-smacked! Bones and cartillage removed or pulverized in a split-instant! No abattoir farm for the Kazakhstani!
I can only speak from my own experience as a hardware design engineer, supervisor, manager, and consultant (now retired) who has interviewed and recommended (or not) hiring scores - if not hundreds - of prospective employees during the course of my career.
If you're getting B's and A's, then don't worry about it too much. 30+ years of experience taught me that I don't want the A+ memorizers. I want the folks that easily made the B+'s and A's but missed perfect marks because they got so passionately caught up in their subject that they weren't inclined to mess with memorizing. I want smart, hard-core technologists - not scholars.
Straight A's will get you into the interview slightly more often, but will not get you hired unless you can communicate your depth of knowledge (and passion) to the interviewer. Remember that you are being interviewed by people just like you, but with more experience.
Exactly. As is stated in other posts, rote memorization is not "learning". To be able to quickly and automatically integrate new phenomena and data with already-understood principles requires that the "old" info be known forwards and backwards.
Hell, to even IDENTIFY new phenomena required a thorough understanding of past work. Even more importantly, to spot contradictions in past work requires deep understanding of said past efforts.
There really is no shortcut. And since there is more past effort to learn, the longer (perhaps) it takes to reach ones peak.
Slashdot Mirror
Yeah (BTW, thanks), but I bet they won't include swimmer's ear in the flick! Opportunities lost...
I'm sure the special effects will be done with strange non-euclidean angles and planes.
Afraid so... (advanced-degree'd hardware design engineer, 20+ years in mil/aero custom switching power supply design).
The half-sine you are drawing is the current into a resistive load. The second waveform is more consistent with rectification into a very large energy-storage cap - like those typically placed on the input stage of a switcher.
What you're observing is the classic (and typical) full-wave-rectified-and-pumped-into-a-capacitor current waveform of an un-PF-corrected power supply. The waveform has an inherent PF of about 50-60% (if I recall correctly - its been a while) or thereabouts - depending on parametric details. So any input power calculation based on simple RMS measurements could be off (high) by 40-50%. Thus...a 1KW measurement instead of (perhaps) 500-600W input. Correction would yield a conversion efficiency in the high 60's (still low) or low 80's (about right). Bottom line: IMHO something's seriously wrong with the measurement/data given.
The Slashdot effect is in full force so I can't RTFA, but given the 1KW in / 400W out description, I would venture to guess that either someone didn't measure or account for power factor on the input current waveform, or the thing was significantly glowing prior to smoke-release. 40% efficiency at that power level - ahem - sucks mightily.
...are belong to us.
Actually, AT&T Bell Labs - (Garland) was kinda picky....
Google, engineers are expected to spend one day a week on a project of personal interest.
AT&T top management tried this in Dallas in the 90's until a manager took them at their word and enforced the 1/5 rule. The resultant loss in overall productivity quickly caught managements eye and the policy was quietly curtailed.
My advice, listen to all the +5 comments, and do the exact opposite.
+5s? Including this one?
So...the phrenologists were right after all?
I suspect that the MSM will go the way print media has gone with the advent of TV and radio proliferation. Print media used to be THE only source; then broadcast media and radio took a lot of their market share. Likewise, I believe that blogs - in a future format perhaps - will significantly overwhelm the MSM as news sources.
As has been posted in other comments, many, many blogs are little better than personal diaries - of no interest to most people. Of course most small, home-town newspapers are in the same boat. But the significant few blogs are beginning to make a greater and greater difference, especially in how the MSM does its reporting and fact-checking. They are also quite effective in calling-to-task the MSM over their many gaffes and outright lies (both by Commission and Ommision). The old paradigm that "the MSM is the only source" is being nibbled at bit by bit.
I feel that this is for the better - you can't have too many sources of info. It just makes sorting the wheat from the chaff a tiny bit harder.
"Gershenfeld predicts one day he will be able to drop the word "almost" from the title of his course."
Not until I can replicate the replicator.
I'm not sure. I've never seen a duck fetus.
not spelling but one to many "on the" :)
That should be "...one too many..."
Glass houses....stones....you get the idea.
Good idea.
BTW - on your sig: How can anybody else be making mistakes? I'm making all of them. Or...am I mistaken?
....how are they going to interconnect them? Won't the obligatory interconnect material re-dope the "junction" or alter the molecule behavior?
Oh! So the socket T MCU things are just big Basic Stamps? With all those I/O pins I bet I could control two Battlebots at once!
Yep. Read it quite some time ago. Researched it on my own, starting with his references. Reviewed the bogus hockey-stick data. reviewed the "arguments" trying (and failing) to prop it up. Then I slowly picked up on the pattern of "assuming its there" that seemed to be inherent in the pro-G-W articles.
I'm quite sceptical about Global warming. Near as I can tell, the phenomenon (if it exists at all) is so buried within greater natural, well-understood cyclic climate variations that NO ONE has been able to show that G-W is even present.
But I didn't comment on the above article because I figured I'd be deluged with flame.
G-W is like religion; you'll never change anyone's mind by arguing the facts, because the facts (or lack thereof) aren't what's motivating them to insist that it exists. Its a matter of dogma and faith. And a dose of liberal feel-good self rightiousness.
Go ahead; mod me to -1; I got excellent karma and a good track record of 4's and 5's, so I really don't give a shit. I'm just killing time - waiting for my roast beef in the oven to get done for dinner.
"If that's so..."
I suspect that you may be confusing belief with religious faith. And - again - the conclusion that "...then Newton et al weren't any good at learning..." does not necessarily follow from RAH's homily.
"Heinlein is entertaining..."
Heinlein was ALWAYS in a dirty-old-man stage. for many years he and his (2nd) wife were active nudists, and had one of the earliest(?) open marriages. The social upheavals of the 60's simply allowed him a bit more literary freedom. But I digress: Why should I take what RAH says with a (implied) larger-than-average grain of salt simply because he was a DOM? Does DOM-hood preclude being intelligent or insightful?
Perhaps if you were better educated and less arrogant, you would realize that your assertion is not the only possibility that can be asserted from the data.
Perhaps the other 40% adhere to the principle that Belief gets in the way of learning.
(R.A. Heinlein - "Time Enough for Love")
Is this the kind of activity we should really be promoting?
You answered your own question in your first sentence: "This is just like real life."
Humans (and spec writers, too!) make mistakes and sometimes overlook aspects of a desired requirement that are important. Recognising this and being ready to deal with it is part of the job for any professional in any industry.
Thank you!
Since you were the first to most graciously post the article from the (so predictably) now-slashdotted server, you win.....(drum roll)....
ONE SIDE OF KAZAKHSTANI BOOSTER-SMACKED BEEF!
Yes good comrade...Kazakhstani beef. Not a substitute! This beef was slow-marinated in pure slavic hydrazine - no oxygen here! - after being gently but firmly caressed by a 13-ton booster moving at terminal velocity! Range-smacked! Bones and cartillage removed or pulverized in a split-instant! No abattoir farm for the Kazakhstani!
Bon Apetite!
I can only speak from my own experience as a hardware design engineer, supervisor, manager, and consultant (now retired) who has interviewed and recommended (or not) hiring scores - if not hundreds - of prospective employees during the course of my career.
If you're getting B's and A's, then don't worry about it too much. 30+ years of experience taught me that I don't want the A+ memorizers. I want the folks that easily made the B+'s and A's but missed perfect marks because they got so passionately caught up in their subject that they weren't inclined to mess with memorizing. I want smart, hard-core technologists - not scholars.
Straight A's will get you into the interview slightly more often, but will not get you hired unless you can communicate your depth of knowledge (and passion) to the interviewer. Remember that you are being interviewed by people just like you, but with more experience.
For what its worth.
Exactly. As is stated in other posts, rote memorization is not "learning". To be able to quickly and automatically integrate new phenomena and data with already-understood principles requires that the "old" info be known forwards and backwards.
Hell, to even IDENTIFY new phenomena required a thorough understanding of past work. Even more importantly, to spot contradictions in past work requires deep understanding of said past efforts.
There really is no shortcut. And since there is more past effort to learn, the longer (perhaps) it takes to reach ones peak.
Thank you - I left that off my own response.