ARIMA: no trend, no seasonality, so what is there to forcast?
Why is removing instationarities a good thing when trying to forecast a time series?
$$f(x,y) = \begin{cases} 2 &amp; 0&lt; x&lt; y&lt;1  \\     0 &amp;\text{otherwise} \end{cases} $$  I need to find   the density function of $y$ and conditional pdf of $X$ given $Y$.   My answer is coming out to be   $2y$ $\frac1y$ Disable HTTPS for a domain that shares IP with another domain that is under HTTPS I am running into a weird problem trying to disable HTTPS for one domain, but the other domain has HTTPS. They both are different websites running on a dedicated server, sharing the same IP address for the domains.  However, I have a domain that does not have a SSL certificate, but the other does. I want to disable HTTPS for the non-certified domain while leaving the other domain with HTTPS on.  I have two different separate vhosts in /etc/nginx/sites-enabled/,   domain1.org (no HTTPS)  server {      listen                      80;     server_name                 www.domain1.org domain1.org;     root                        /var/www/domain1.org;     index                       index.html index.php index.htm;      error_log                   /var/www/logs/domain1.errors.log;      [ ... ]   domain2.com (with HTTPS)  server {      listen                      443 ssl;     server_name                 domain2.com www.domain2.com;      # INCLUDE SSL CERTIFICATE     include                     sites-enabled/domain2_ssl_include;       root                        /home/domain2/www/www;     index                       index.html index.php index.htm;      [ ... ]   I've included a listener to the port 443 for domain1.org, but once I do that, I get an aborted error from Firefox saying (when accessing ):     This Connection is Untrusted      You have asked Firefox to connect securely to domain1.org, but we can't confirm that your connection is secure.   I opened the technical data, it appears that the domain1.org is using the domain2.com SSL certificate:     domain1.org uses an invalid security certificate.      The certificate is only valid for the following names:    *.domain2.com , domain2.com        (Error code: ssl_error_bad_cert_domain)   So I added this to domain1.org vhost configuration:  server {      server_name                 domain1.org www.domain1.org;      listen                      443 ssl;      rewrite ^ http://domain1.org permanent; }   Which still gets me prompted with the Firefox error.  Now... when I access to , I get an 400 error from nginx saying this:     400 Bad Request      The plain HTTP request was sent to HTTPS port   I am not entirely sure what to do, disabling the https with ssl off; has no effect. How can I actually disable HTTPS for domain1.org but not for domain2.com?  I am using Ubuntu 12.04 running nginx 1.2.6. Let $A$ be a commutative ring, $I$ an ideal of $A$ and $M$ an module over $A$. Is it true that $\operatorname{Ann}(M/IM) = \operatorname{Ann}(M) + I$?    One inclusion is certainly true, but I don't know about the other one. If the above statement does not hold in general, does it perhaps for finitely generated modules? How to create this curved 90-degree-angle quickly Possible to do a MySQL foreign key to one of two possible tables? When I capture packets using the packet analyser wireshark while visiting  I can see packets that use the HTTP protocol (e.g.a GET request). My Get request uses 4 protocols: Ethernet II, IPv4, TCP and HTTP.  For the IPv4 I can see my own local IPv4 address of my pc as the source, for the destination I see the IPv4 address 91.198.174.225. When I go to this address in my browser I get to some wikipedia related website that says'wiki does not exist'. Why am I not seeing the Hydrogen article when I go to that ip address? I'm getting the following error message:     System.QueryException: Didn't understand relationship 'AccountContactRelation' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.   Select Email, Id, (Select ContactId, AccountId From AccountContactRelation) From Contact  In AccountContactRelation object there are two lookup fields for Account and for Contact.  Please advise how to avoid such error message? Why can't we see images reflected on a piece of paper? Does the pilot of a rocket ship experience an asymptotic approach to the speed of light? A question has recently come up that goes beyond my knowledge of special relativity.  Suppose a pilot has his foot on the gas pedal of a rocket ship and keeps it applied to achieve a constant acceleration, and he has a magical engine that can maintain the thrust needed to accomplish such acceleration even as the vehicle acquires mass.  He measures his acceleration at periodic intervals and sums it up as he goes.  Observers perceive the rocket to increase in speed and gradually approach the speed of light (but never reach it). Two possibilities are being debated for what the pilot observes, and my preference is for the first:   Time dilation gives him the impression that the summation of his readings are approaching light speed at a constant rate, but there is an asymptote involved here even in the inertial frame such that he never actually perceives himself to reach, let alone exceed, $c$, because time slows down to a crawl (as seen from the reference frame) before this can happen. Although to observers he is only approaching $c$, it is possible for the summation of the measurements on his accelerometer to indicate that he has surpassed $c$ and is now traveling faster than light.  From the reference frame he is approaching $c$ and his instruments in the inertial frame tell him that he has surpassed it.   I assume (1) is true beyond a doubt?  If so, is there a straightforward explanation for this? How to redirect with "www" URL's to without "www" URL's or vice-versa? I am using ASP.NET 2.0 C#. I want to redirect all request for my web app with "www" to without "www"  www.example.com to example.com  Or  example.com to www.example.com  Stackoverflow.com is already doing this, I know there is a premade mechanism in PHP (.htaccess) file. But how to do it in asp.net ?  Thanks How can I set the maximum draw type for multiple objects? The rulebook states that carrying capacity is the strength score times 15 (lbs). Find familiar allows me to get a hawk, which has a strength score of 5. This results in a carrying capacity of 75 lbs. This is well within the range of weights for small people such as gnomes or halflings. Does this mean my familiar can carry them and fly away (given they do not struggle)? $ \frac{1}{a^{2} + b^{2} + 1} + \frac{1}{b^{2}+c^{2}+1} + \frac{1}{c^{2} + a^{2} + 1} \ge 1 $, prove $ab + bc + ca \le 3$ If $a,b,c$ real numbers such that $$ \frac{1}{a^{2} + b^{2} + 1} + \frac{1}{b^{2}+c^{2}+1} + \frac{1}{c^{2} + a^{2} + 1} \ge 1 $$,  prove that $ab + bc + ca \le 3$.     Attempt:  Assume that $a,b,c &gt; 0$.   $$ \frac{1}{a^{2} + b^{2} + 1} + \frac{1}{b^{2}+c^{2}+1} + \frac{1}{c^{2} + a^{2} + 1} \ge 1  $$ $$ \implies  (a^{2} + b^{2} + 1)(b^{2}+c^{2}+1) + (a^{2} + b^{2} + 1)(a^{2}+c^{2}+1) +  (a^{2} + c^{2} + 1)(b^{2}+c^{2}+1) \ge (a^{2} + b^{2} + 1)(b^{2}+c^{2}+1)(c^{2} + a^{2} + 1)$$  $$ \implies  ((ab)^{2} + (ac)^{2} + (bc)^{2} + a^{2} + 2 b^{2} + c^{2} + b^{4} + 1) + ((ab)^{2} + (ac)^{2} + (bc)^{2} + b^{2} + 2 a^{2} + c^{2} + a^{4} + 1) + ((ab)^{2} + (ac)^{2} + (bc)^{2} + a^{2} + 2 c^{2} + b^{2} + c^{4} + 1) \ge (a^{2} + b^{2} + 1)(b^{2}+c^{2}+1)(c^{2} + a^{2} + 1)$$  $$ \implies  3((ab)^{2} + (ac)^{2} + (bc)^{2}) + 4(a^{2} + b^{2} + c^{2}) + (a^{4}+b^{4}+c^{4}) + 3  \ge (a^{2} + b^{2} + 1)(b^{2}+c^{2}+1)(c^{2} + a^{2} + 1)$$  Next, notice  $$(a^{2} + b^{2} + 1)(b^{2}+c^{2}+1)(c^{2} + a^{2} + 1) = ((ab)^{2} + (ac)^{2} + (bc)^{2} + a^{2} + 2 b^{2} + c^{2} + b^{4} + 1)(c^{2} + a^{2} + 1) $$ $$ = (abc)^{2} + a^{2}c^{4} + b^{2}c^{4} + (ac)^{2} + 2(bc)^{2} + c^{4} + b^{4}c^{2} + c^{2} + a^{4} b^{2} + a^{4}c^{2} + (abc)^{2} + a^{4}  + 2(ab)^{2} + (ac)^{2} + b^{4}a^{2} + a^{2} +  (ab)^{2} + (ac)^{2} + (bc)^{2} + a^{2} + 2 b^{2} + c^{2} + b^{4} + 1 $$ $$ = 2(abc)^{2} + 3(ac)^{2} + 3(bc)^{2} + 3(ab)^{2} + c^{4}a^{2} + c^{4} b^{2} + b^{4}a^{2} + b^{4} c^{2} + a^{4}b^{2} + a^{4} c^{2} + a^{4} + b^{4} + c^{4} + 2(a^{2} + b^{2} + c^{2}) + 1  $$  So we have  $$ \frac{1}{a^{2} + b^{2} + 1} + \frac{1}{b^{2}+c^{2}+1} + \frac{1}{c^{2} + a^{2} + 1} \ge 1 $$ $$ \implies  2(a^{2} + b^{2} + c^{2}) +  3  \ge 2(abc)^{2}  + c^{4}a^{2} + c^{4} b^{2} + b^{4}a^{2} + b^{4} c^{2} + a^{4}b^{2} + a^{4} c^{2} + 1 $$ Getting started with ArcObjects? What is the best route or place to get started with ArcObjects if one is not a developer and not aiming to become a developer?  I've been using gis professionally for a long time, almost two decades, arcinfo/arcgis for most of that; I'm pretty good. I'm learning software development, and even have a modestly successful small python application used in a public project; I'm not good! I don't want to become a full fledged software developer but I keep running into things I just can't do without programming (). In the arcgis world this puts me pretty squarely in the python camp, which is fine by me since I like python, however python does not have straightforward access to ArcObjects. (Python and ArcObjects , but it's an unsupported route. This question is about following a beaten path.)  I need to get started, but where?  to get started with the  but $1500/yr is definitely not in my budget, and sounds like using a sledge hammer to swat mosquitos. And which language .NET, Visual Basic, or Visual C++?    UPDATE: Thank you everyone for the wonderful answers. In light of them I realise  I unecessarily narrowed the scope of my question be pre-supposing "ArcObjects" is the direction I need to go in. A more open ended formulation is more along the lines of:     I keep running into problems I just   can't solve with arcgis and python   alone. What else can I learn/use to   solve problems like X? I've no   interest or intention of becoming a   software developer. I just need to do   a couple things which aren't exposed   to the arcgis python modules. Get value of R, G, B by color Why are the objects in my hair particle system not sitting on top of the ground? I made a hair particle system and set the Dupli Group to a group of 3 objects. Each of the 3 objects has:   it's origin set to be touching the XY plane (on layer 2) it's Scale applied to 1 and it's Rotation applied to 0     I am trying to get each of the objects to sit directly on top of the ground, but instead, they are centered in the plane, half above the plane and half below the plane:      What am I doing wrong? Here is . I remember reading a sci-fi story where astronauts visit a planet, which is covered in stationary aliens with mile long necks that filter feed from the atmosphere.  It was published between 1960 and 2000.    It was in English and involved a pair of astronauts that went from planet to planet on a tour or something, though I don't know details of any other planets they visited. In MTG, what happens when a player loses in multiplayer? "Not with a whimper, but with a roar of triumph!" Looking for the title of an old sci-fi book, pretty sure it is a Baen or Del Rey imprint. Basically, mankind has reached the stars and expanded throughout the galaxy. Suddenly, an unknown race appears and begins a war of extermination against man. Finally, the galaxy is desolate, and one man remains. He is in a starship with an AI and becomes injured in the battle.  The ship's AI takes over and speeds out into the unknown, followed by the last remaining member of the unknown alien race. As all speeds are at tremendous multiples of the speed of light, the man cannot get away, but the alien cannot catch up.  Finally, communication is opened, at which point the man asks "why?" The alien tells him that man had discovered immortality, but that it required the death of a member of a race known as the Flower People for every human who achieved immortality. The alien says that Man would have found the answer eventually, but that genocide was so intolerable that the aliens came from another dimension, to which they could never return, to stop Man, which resulted in the war of extermination.  Finally, the light speeds become so great that the two remaining living beings in the universe approach the Big Crunch. As the Man begins to dive into the singularity, with the alien hot on his heels, he says that maybe there will be room in the next universe for both races to live in peace, and the final line is "not with a whimper, but with a roar of triumph"! I had studied group theory a year ago, but still could not understand the proof involving The Correspondence theorem.  let $G$ be a group and let $N⊴G$, where  $N⊴G$ indicates that $N$ is a normal subgroup of $G$. Then there is a bijection from the set of subgroups $A$ of $G$ that contain $N$ onto the set of subgroups $\overline A $=$A/N$ of $G/N.$  Can anyone explain the steps to me in:  $(1.)$ a very easy-going manner so that I understand importance of each step. $(2.)$I don't require the proof but only how the step follow each other .  I'll be thankful if there is anyone kind enough to do this....