I'm trying to estimate available power from a solar cell like this one PRT-13781    Includes:  1x Solar Panel - 2W 1x Barrel Plug Adapter - 3.5mm to 5.5mm   Features:  Monocrystalline cells - 19% efficient Open Circuit Voltage: 7.0V Peak Voltage: 6.0V Peak Current: 378mA Peak Power: 2.27 Watts Four screws on back corners of panel allow multiple mounting options Waterproof Urethane Coating UV Resistant   Obviously, the 2W will be obtained in ideal conditions, clear sky, sunny, etc and at MPPT point.  How can I estimate available power for cloudy days, (variation with temperature will be also nice to know) etc. I cannot find relevant documents to start with, however, I will do at some point some measurements.   Until then, I am looking to best effort estimate just to have a start point in choosing the DC/DC MPPT charger, discharging the battery in my actual load conditions, etc.  For example this post question almost the same    but no relevant calculation based on illumination (lux) or percent of rated illumination vs. generated power.  EDITED We can close this question, I finally found a very well documented answer here    Thanks user @Russell McMahon
This is homework. I've tried my best to find the best answer that I could understand and could be accepted by my lecturer.   I've searched my lecture notes, wiki and google to find some good explanation defining solar irradiance. But somehow I still don't understand how I should 'define solar irradiance'. Can someone give me a few good sentences explaining solar irradiance. What are the changes, if any, in a photovoltaic cell (in terms of short-circuit current and open-circuit voltage) if the irradiance is reduced by 50%?
With services like Google Finance or Yahoo Finance it is very convenient to find the historical stock price metric of a listed company, but if the company is not listed, I can't find the data.  For example, I want to see the price metrics for Macromedia, which had been listed in 1993 on NASDAQ (MACR), then acquired by Adobe in 2005. How could I find its historical price metrics? DDL Trigger in MySQL? Can someone help me figure out the big-O for the recurrence relation $T(n) = T(n^{1/2}) + 1$?  I didn't think the master theorem would work since it requires $T(n) = T(n/b)$... to have $b$ as a constant. I was wondering if anyone could shed some light on a method to approach this problem? (not looking for a solution) If $2a_{n+2} \le a_{n+1}+a_n$, then $\lim \sup a_n \le \frac23 a_2 + \frac13 a_1$ This is a reformulation of a deleted question:  If  $a_1 &gt; 0$ and $a_2 &gt; 0$ and $2a_{n+2} \le a_{n+1}+a_n$,  show that  $\lim \sup a_n \le \frac23 a_2 + \frac13 a_1$.  My proof involves showing that $a_{n+2} \le u_{n} a_{n+1} + (1-u_n)a_n $ where $u_n \to \frac23$, and I wondered if there is a simpler proof.  I will post my proof in a couple of days if no one does. I have 256 colors working just fine in konsole,. I thought I'd give tmux a try because, unlike screen, it seems to support vi mode.  However I find that the colors of my prompt show up and this is most likely because I have a 256 color mode prompt. What do I need to do to get tmux to recognize all 256 colors? Can't deep learning models now be said to be interpretable? Are nodes features? For statistical and machine learning models, there are multiple levels of interpretability: 1) the algorithm as a whole, 2) parts of the algorithm in general 3) parts of the algorithm on particular inputs, and these three levels split into two parts each, one for training and one for function eval. The last two parts are much closer than to the first. I'm asking about #2, which usually leads to better understanding of #3). (if those are not what 'interpretability' means then what should I be thinking?)  As far as interpretability goes, logistic regression is one of the easiest to interpret. Why did this instance pass the threshold? Because that instance had this particular positive feature and it has a larger coefficient in the model. It's so obvious!  A neural network is  the classic example of a model that is difficult to interpret. What do all those coefficients mean? They all add up in such complicated crazy ways that it is hard to say what any particular coefficient is really doing.  But with all the deep neural nets coming out, it feels like things are becoming clearer. The DL models (for say vision) seem to capture things like edges or orientation in early layers, and in later layers it seems like some nodes are actually semantic (like the proverbial ). For example:    ()  This is a graphic () created by hand for presentation so I am very skeptical. But it is evidence that somebody thinks that is how it works.  Maybe in the past there just weren't enough layers for us to find recognizable features; the models were successful, just not easy to post-hoc analyze particular ones.  But maybe the graphic is just wishful thinking. Maybe NNs are truly inscrutable.  But the many graphics with their nodes labeled with pictures are also really compelling.    Do DL nodes really correspond to features? How do I uninstall Ubuntu Wubi? Why disable Fast Boot on Windows 8 when having dual booting? Problem:  Ajax suggest-search on [n] ingredients in recipes. That is: match recipes against multiple ingredients.  For instance: SELECT Recipes using "flower", "salt" would produce: "Pizza", "Bread", "Saltwater" and so forth.  Tables:  Ingredients [     IngredientsID INT [PK],     IngredientsName VARCHAR ]  Recipes [     RecipesID INT [PK],     RecipesName VARCHAR ]  IngredientsRecipes [     IngredientsRecipesID INT [PK],     IngredientsID INT,     RecipesID INT ]   Query:  SELECT     Recipes.RecipesID,     Recipes.RecipesName,     Ingredients.IngredientsID,     Ingredients.IngredientsName FROM     IngredientsRecipes      INNER JOIN Ingredients     ON IngredientsRecipes.IngredientsID = Ingredients.IngredientsID      INNER JOIN Recipes     ON IngredientsRecipes.RecipesID = Recipes.RecipesID WHERE     Ingredients.IngredientsName IN ('salt', 'water', 'flower')   I am currently constructing my query using ASP.NET C# because of the dynamic nature of the WHERE clause.  I bites that I have to construct the query in my code-layer instead of using a stored procedure/pure SQL, which in theory should be much faster.  Have you guys got any thoughts on how I would move all of the logic from my code-layer to pure SQL, or at least how I can optimize the performance of what I'm doing?  I am thinking along the lines of temporary tables:  Step one: SELECT IngredientsID FROM Ingredients and INSERT INTO temp-table  Step two: SELECT RecipesName FROM Recipes joined with IngredientsRecipes joined with temp-table.IngredientsID Prime dividing the binomial coefficients It is quite easy to show that for every prime $p$ and $0&lt;i&lt;p$ we have that $p$ divides the binomial coefficient $\large p\choose i$; one simply notes that in $\large \frac{p!}{i!(p-i)!}$ the numerator is divisible by $p$ whereas the denominator is not (since it is a product of numbers smaller than $p$ and $p$ is prime).  My problem is with generalizing this argument for $q=p^n$. I'm looking for the most elegant and simple way to prove that $p$ still divides $\large q\choose i$. Could one fire a bullet with sufficient speed to leave the Earth? For $0 < x < \pi/2 $, prove that $x + \frac{x^{3}}{3} <\tan x $ I proved as follows:  Let $f(x) = \tan x -  x - \frac{x^{3}}{3}.$ Then $f '(x) = \sec^{2}x - 1 - x^{2}$ and $f''(x) = 2\sec^{2}x\tan x-x &gt; \tan x - x,$ since $\\tan x &gt; x,$ $f''(x) &gt; 0$ so $f'(x)$ is increasing. Since $f '(0) = 0,$ $f '(x) &gt; 0$ for all $x \in (0, \frac{\pi}{2}).$ So $f(x)$ is increasing. since $f(0) = 0,$ $f(x) &gt; 0$ for all $x \in (0, \frac{\pi}{2}).$  But my proof seems complex. Is there any simpler way to prove this? What is the difference between a[bc]d and a{b,c}d? Why do people use a{b,c}d when there is already a[bc]d? I found an example in the  for Dynamic LINQ that allows you to use a sql-like string (e.g. OrderBy("Name, Age DESC")) for ordering. Unfortunately, the method included only works on IQueryable&lt;T&gt;. Is there any way to get this functionality on IEnumerable&lt;T&gt;? Is it possible to enable System Protection from the command prompt? Why do video cables (DVI, VGA) still screw in? This is a follow up from this .  I'm using this slightly modified script to enumerate all installed MSI packages:  strComputer = "."  Set objWMIService = GetObject("winmgmts:" &amp; _     "{impersonationLevel=impersonate}!\\" &amp; _     strComputer &amp; _     "\root\cimv2")  Set colSoftware = objWMIService.ExecQuery _     ("SELECT * FROM Win32_Product")     If colSoftware.Count &gt; 0 Then     For Each objSoftware in colSoftware         WScript.Echo objSoftware.Caption &amp; vbtab &amp; _         objSoftware.Version     Next Else     WScript.Echo "Cannot retrieve software from this computer." End If   What is surprising however, is its abysmal performance. Enumerating the 34 installed MSI packages on my XP box takes between 3 and 5 minutes !  By comparison, the Linux box that sits besides is taking 7s to enumerate 1400+ RPMs... sigh  Any clues on this ? Finding an expression for $\tan (a+ b + y)$ which involves only $\tan a, \tan b,$ and $\tan y$. Windows Spotlight Source and Save locations? Where are the images from  coming from?  Where are they being saved on my system?  Is there any way for me to point this at my own source of images? What is there to do after beating the Elite Four/Champion (Post-Game)? I've defeated the Elite Four and the Champion. The credits rolled and I've been teleported to my home in Vaniville Town. What is there to do now? Any specific events/features that are unlocked now?  I already know of and caught Mewtwo and Zyrgarde.