Three Tiered Architecture: Basic Full Stack Analytics Architecture using R

Descriptive, Diagnostic and Predictive Analytics – and their corresponding specializations reporting, business intelligence, and data science – do not operate independently in an organization; at least not if they are to operate effectively.

A relatively new term emerging into our business vocabulary is “Full-Stack Data Science”; describing how all layers of analytics and data must operate in concert to maximize organizational returns on analytical activities. (See our post on emerging data science architecture for more detail.)

Let us break down the phrase “Full-Stack Data Science.” “Data Science” (as we’ve mentioned in previous articles) remains a nebulous term at best. As a quick refresher, Data Scientist tend to fall into two categories: one, PhDs in computer science who create programs leveraging statistics, and two statisticians who understand how to incorporate programmatic solutions to accelerate data transformations and insights.

“Full-Stack” is a term appropriated from web development. In Web Dev a “Full Stack Developer” creates the user interface, data interface, and the data repository, as well as implements the technologies for users to access their applications via the web.

Full Stack Data Science is very similar to Full Stack Web Development. The Data Science stack requires some way to interface with data, a means to transform the data (i.e. mathematical operations), data storage, and an architecture to support the entire process.

Below we will provide some high level examples of Web Dev and Data Science Full Stack use cases as well as some technologies often used. This is not an exhaustive list by any means, only designed to introduce the terminology and provide a frame of reference for those familiar with the more common web based tools and technology.

Full Stack Terminology

User Interface

  • Definition: How the end user accesses and interacts with the application
  • Examples:
    • Web Dev: User goes to department store website and is able to quickly find desired product
    • Data Science: Analysts wishes to see results of a model or report; user wishes to change parameters of existing model
  • Web Development Technologies:
    • HTML; CSS; JavaScript
  • Data Science Technologies:
    • Shiny; SSRS; Front End of BI Tools (e.g. Tableau; Spotfire)

Data Interface

  • Definition: How the data entered into the user interface is moved to the data storage layer and how data in data  layer is retrieved given user interface requests and information required for website
    • Data may be passed directly from interface to repository or it may be transformed in some capacity (e.g. aggregations, type changes, mathematical operations, modeling)
  • Examples:
    • Web Dev: User purchases good from website, credit card number is transferred to banking system and purchase is saved in payment processing system. Shopping history may be retrieved by user at a later date.
    • Data Science: Support Vector Machine Unsupervised Learning processes generates product suggestions for potential online customers; high value customers identified via squared error cost function neural network model
  • Web Development Technologies:
    • PHP; Angular.js; node.js
  • Data Science Technologies:
    • R; Spark; Python; SSIS; T-SQL; Data Modeling aspect of BI Tools(e.g. Tableau VQL; Spotfire TERR and Information Designer)

Data Repository (Web Dev and Data Science)

  • Long term storage of data required for websites, predictive modeling, reporting
  • Example: Long term storage of customer information; ERP; CMS
  • Technologies:
    • SQL; MongoDB; Cassandra; HBASE; Delimited Text; XML; Unstructured

User Interface

The first thing most people think about when “Analytics” is mentioned are analytics visuals. Visualization is critical in all levels of analytical maturity – and one of the two core functions of a good UI is its ability to communicate information succinctly via visuals, that is, its ability to send information to the user

User interactability is the second core function – i.e. the ability of the user to send information into the stack via the UX. Early on in analytics maturity Interactivity is more important in development than it is to the end users; however just as website more from simple communicators of information in web 1.0 to dynamic communities full of user generated content in web 2.0, so too do organizations begin moving analytics into the hands of their business users as analytics needs grow.

Analytics maturity typically starts at the user interface level. Creating interactive visualizations and allowing users to create their own cross-tabs and visualization is commonly known as “self-service analytics” and acts as a bridge between descriptive and diagnostic analytics. User engagement with the data means that users are able to ask “Why” certain results are present and begin to answer the question themselves.

Business Intelligence Platforms

R Integration

Modern Business Intelligence platform provide all the user interface functionality (and some data interface) required in the modern data science stack. For example, Spotfire and Tableau both have R integration out of the box. R integration means the BI platform has access to all the data interface functionality in R – including, but not limited to, data shaping, statistical modeling, read/write to SQL, etc.

Web Functionality

Business Intelligence platforms typically use internet browser based solutions for large scale deployments (~+50 users), as such, they allow developers to either embed a BI visualization into an existing website (See: http://www.tibco.com/blog/2015/01/17/responsive-design-with-bootstrap-spotfire/) or they allow website development and formatting directly in the analysis.

The platforms which truly embrace web functionality have javascript and html capability. With javascript, the door is open to the giant library of visualization created by the javascript community, some examples: processing.js; d3.js, raphael.js, ember.js

Entire books have been written on each one of those libraries so I will leave it as an exercise for the reader to research more about javascript libraries.

Direct Connections to Databases

It may sound like there needs to be a separate application as the data interface layer, this is not necessarily true. All BI platforms allow for direct connection to the data layer. Their ability to both interface with and display data makes them a low barrier to entry for advancing analytic maturity.

However, BI platforms are built to be read only from data. A separate data interface layer needs to be present for the read/write to data that is required in a true data science full stack.

As an aside, if the platform of choice for the organization does not have some type of data interface integration (e.g. python, matlab, SAS, Spark, R), the statistical data modeling and shaping done by said data interface platforms must happen asynchronously from the user interface – meaning, a separate statistical process not controlled by the BI Tool must read data and write results to the data layer, which will then be consumed by the BI Tool.

Data Interface

R as a Governed Hub

R is awesome for full-stack data science, don’t get me wrong, but there are plenty of other languages / platforms that are better in different way. For example, Python is better at data manipulation and has easier syntax. Spark and H20 are better for large scale computation. But this is very important, every one of tools can be called within a R script.

If I want to write my output to a SQL Database? There’s sqldf. Do I have a cool pyhon script that I need to kick-off and listen to output? There’s rPython. What about Spark? It  has native integration with R in SparkR.

More importantly, we can keep all our code objects as a version controlled library. Allowing developers to update and extend code functionality independent of the BI platform. While UX analysts do not need to have multiple versions of the same code floating around – they don’t even need to learn any programming.

Passing Values to R

Once that data is in R, you have access to almost 50 years of mathematical and data operations libraries.  You can execute models and send them right to the Business Intelligence platform for evaluation and reports.

In fact, the model evaluation can become more robust. Remember, BI Platform now have R integration as well. In many cases users can input or select values in the BI User Interface and have them included in an R function, which then gives the user access to all the other functionality available in R!

From hyper parameter tuning to adding notes to an insert SQL statement, manipulating R scripts via user interface in a BI platform greatly expands the base functionality of BI Tools and is a major part of why R is a preferred part of a Full-Stack Data Science Environment.

R can also access data online in websites and RESTful services via tools like RCurl and httr. Imagine a use case where we want to see the conversations, subject, and sentiment of all users across a set of websites. We can create a full stack solution where an end user can type in the name of a website within Spotfire*, R scrapes the data page by page. Each page getting processed into natural language blocks (Verb, Subject, DO, etc.) into a streaming Spark application where it’s then written to a Graphical Database indicating the relationship between phrases, pages, people, etc. All this time, the sentiment and relationships between websites, pages, users, sentiment, and products mentioned.

*Note: I am specifically stating Spotfire here because I know from personal experience Spotfire is capable of implementing this solution.

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