Articles by Huidong Tian

Generate Distinct Colors

June 16, 2014 | Huidong Tian

When plot with R (or some other software), it doesn’t bother you a lot for choosing colors if you have only several data series. For example, if I want to create a figure for 5 data series, I can choose red, green, dark green, blue and black. But what if ... [Read more...]

A Shiny-app Serves as Shiny-server Load Balancer

April 30, 2014 | Huidong Tian

The Shiny-app on open-source edition Shiny-server has only one concurrent, which means it can run only for one user at a time point. But it can host multiple Shiny-apps, which can run synchronously. So, if we create severl Shiny-apps with different names but same function, then we can let more ... [Read more...]

Set Up Shiny-server on

April 23, 2014 | Huidong Tian

RStudio supplies several servers for hosting user’s apps, e.g.,, Thanks a lot to RStudio who has contributed many excellent R libraries! I want to set my shiny-server on a virtual private server (VPS), because I have ... [Read more...]

Shiny-server Open Source Edition: Solution for CPU Bound Apps

March 19, 2014 | Huidong Tian

Shiny-server integrates the statistic power of R with web, convenients the statistical analysis through web. Users can do complecate statistical anlysis through their web browsers. However, most of statistical analysis of R are CPU bound computation, that means CPU utilization is high, perhaps at 100% for many seconds. This leads to ... [Read more...]

Encrypt user’s password with md5 for you Shiny-app

February 14, 2014 | Huidong Tian

In a previous blog, I post a simple authentication method for Shiny-app, and received several comments mainly concerning that I should encrypt user password. I agree, user’s password can be intercepted when it was transferring. To secure users’ personal information, I think we should consider both server and client ... [Read more...]

Turn your Mac into a server for sharing photos

February 11, 2014 | Huidong Tian

A month ago, I attended a friend’s wedding as a photographer (I am not good at shooting, just have a not so bad camera). I took more than 1000 pictures in high quality format. Later, I relized to share them with the guests attended wedding is a challenge: I need ... [Read more...]

Who Touched My Shiny-app?

February 11, 2014 | Huidong Tian

When we created a Shiny-app, deployed it on a server and open it to public, we must have interesting of who visited our app, and if possible, where they from and what they have done. To achieve this, we need a user behavior tracking feature if we are not using ... [Read more...]

Automatic Notice When Vacancy Available

February 26, 2013 | Huidong Tian

Today, I visited a webpage inadvertently and found several job positions that I am competent with, unfortunately all of them has expired. How many chances we lost in this way?! So I decide to do somthing to limit this kind of loss, and of course using our smart R! The ... [Read more...]

One R Function A Day.

February 11, 2013 | Huidong Tian

As a R user with 5 years experience, I still have some basic functions that never used or never thought they could exist. Many times I was suprised with some elegant R functions, such like strwidth, parent.frame, etc. No one can know all R functions (... [Read more...]

Using R to refine the search result of

December 12, 2012 | Huidong Tian is the most popular website in Norway. It supplies a lot of features, such as booking flight tickets, finding job, renting and sales of houses, cars and other properties, etc. I just have some experience with it. I sold and bought cars, apartment and some other stuff. ... [Read more...]

Facts About R Packages (2)

August 29, 2012 | Huidong Tian

R Packages All Well maintained? There are so many R packages, can they all be trusted? or are they well maintained? To answer this question, we just need to take a look of their archive histories. If a package has many versions, we can take that as th... [Read more...]

Facts About R Packages (1)

August 29, 2012 | Huidong Tian

R Packages growth Curve Why R is so popular? There are a lot of reasons, such as: easy to learn and convenient to use, active community, open source, etc. Another important reason is the numerous contributed packages. Up to yesterday, there are 4033 R... [Read more...]
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