I started to lose respect for people commenting on this board...I don't see what is the big deal with this, and why would you even publish a paper on it.
Here is the thing: Temperature reading of battery may not even be the actual temperature value of the battery. Even the circuits itself that read temperature is sensitive to temperature (they have the same correlation with temp. as battery..Higher the temp. is, higher the leakage current, and hotter your device will be). So temperature reading itself will be combination of things, most of which have similar correlation against temperature of the environment. This is a well-known fact to all people working in semiconductor industry and we simulate things against temp. all the time.
And when you average out thousands of reading from different cell-phones, you will get rid of all those noise coming from phone-usage, whether person holds the phone or keep in in his pocket ..etc.
As a side node, if the batteries in each cell-phone made by different manufacturers, their temp. reading will also be different and will add a noise as well.
You built an app to read temp., OK fine. But, it just annoys me the fact that they talk about it as if this was a new discovery, and publish a scientific paper about it :)
> I don't see what is the big deal with this, and why would you even publish a paper on it.
The fact that we suddenly have a boatload of free weather data? Nobody installed any weather stations - this is information fallout being put to good use. That's pretty awesome.
> This is a well-known fact to all people working in semiconductor industry and we simulate things against temp. all the time.
Simulating how an electronic circuit works under different temperatures is one ting, but do you do actual measurements to see what factor the ambient temperature has on the measured temperature of a phone battery? How about having the phone touch a 37 degrees centigrade heat bath on one side (in other words: a human body) and ambient air on the other? Before this paper, could you have made any reliable prediction on how big an influence ambient temperatures were on the sensors in the battery?
Knowing how much of that temperature is body heat, ambient heat and heat produced by the phone/battery requires analysing the data - for all we know the ambient temperature could have been completely insignificant compared to body heat and heat produced by the phone. Maybe you could model it and predict it, but even then the proof of the pudding is in the eating.
You and others here can complain that it's no surprise that thermometers measure temperature, but actually analyzing the data, discovering that ambient temperature is a significant factor, and figuring out the Pearson coefficient required to put it to use is a discovery, and certainly worth publishing about.
you do actual measurements to see what factor the ambient temperature has on the measured temperature of a phone battery? How about having the phone touch a 37 degrees centigrade heat bath on one side (in other words: a human body) and ambient air on the other? Before this paper, could you have made any reliable prediction on how big an influence ambient temperatures were on the sensors in the battery?
Even under lab conditions, I doubt you'd get a good correlation between battery temperature and lab temperature if the phone were being used. Across an ensemble of phones and aggregating battery temperatures, you might expect to do better, but that would only prove this works in lab conditions.
These phones were sometimes indoors, sometimes outdoors, sometimes in bags, in conditions that are hard to replicate unless you have a very good model of average user behaviour.
We're working on ways to better detect the situation of the phone at the point of a reading, but even then it takes about 30minutes for battery temperature changes to take effect. If a phone was outside 15 minutes a go, the outdoors temperature will still have a large impact.
Modelling this or testing in lab conditions is not trivial!
Sorry, buddy...but, this is no more than a glorified Excel sheet work, or a high school science project...and you know that.
Nonetheless, it's useful..my only objection is for them to say it as if this was unexpected, something new, a discovery...which is not. If they talked to an hardware engineer, he would probably tell them what to expect anyways.
Here is the thing: Temperature reading of battery may not even be the actual temperature value of the battery. Even the circuits itself that read temperature is sensitive to temperature (they have the same correlation with temp. as battery..Higher the temp. is, higher the leakage current, and hotter your device will be). So temperature reading itself will be combination of things, most of which have similar correlation against temperature of the environment. This is a well-known fact to all people working in semiconductor industry and we simulate things against temp. all the time.
And when you average out thousands of reading from different cell-phones, you will get rid of all those noise coming from phone-usage, whether person holds the phone or keep in in his pocket ..etc.
As a side node, if the batteries in each cell-phone made by different manufacturers, their temp. reading will also be different and will add a noise as well.
You built an app to read temp., OK fine. But, it just annoys me the fact that they talk about it as if this was a new discovery, and publish a scientific paper about it :)