Taking the EMC Data Science associate certification

May 13, 2013 at 10:06 am | Posted in Big Data, Performance | 12 Comments
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In the last couple of weeks I’ve been studying for the EMC data science certification. There are a number of ways of studying for this certificate but I chose the virtual learning option,which comes as a DVD that installs on a Windows PC (yes Macs are no good!).

The course consists of six modulesĀ and is derived from the classroom-based delivery of the course. Each module is dedicated to a particular aspect of data science and big data with each following a similar pattern: a number of video lectures and followed by a set of lab exercises. There are also occasional short interviews with professional data scientists focusing on various topical areas. At the end of each module there is a question and answer multiple-choice to test your understanding of the subjects.

The video lectures are a recording of the course delivered to some EMC employees. This has some pros and cons. Occasionally we veer off from the lecture to a group discussion. Sometimes this is enlightening and provides a counterpoint to the formal material, however sometimes microphones are switched off or the conversation becomes confused and off-topic (just like real life!). Overall this worked pretty well and make if easier to watch.

The labs are more problematic. You get the same labs as delivered in the classroom course however you simply get to watch a camtasia studio recording of the lab with a voiceover by one of the presenters. Clearly the main benefits of labs is to enable people to experience the software hands-on, an essential part of learning practical skills. Most of the labs use either the open source R software or EMCs own Greenplum which is available as a community software download. There is nothing to stop you from downloading your own copies of these pieces of software and in fact that is what I did with R. However many of the labs assume there are certain sets of data available on the system; in some cases this is CSV files which are actually provided with the course. However relational tables used in Greenplum are not provided. It would have been nice if a dump of the relational tables had been provided on the DVD. A more ambitious idea would have been to provide some sort of online virtual machine in which subscribers to the course could run the labs.

Since the lab guide was provided I was able in many cases to follow the labs exactly, where the data was provided, or something close to it by generating my own data. I also used an existing Postgres database as a substitute for some of the Greenplum work. However I didn’t have time to get MADLib extensions working in Postgres (these come as part of out-of-the-box Greenplum). This is unfortunate as clearly one of the things that EMC/Pivotal/Greenplum would like is for more people to use MADLib. By the way, if you didn’t know, MADLib is a way of running advanced analytics in-database with the possibility of using Massively Parallel Processing to speed delivery of results.

The first couple of modules are of a high-level nature aimed more at Project Manager or Business Analyst type people. The presenter, David Dietrich, is clearly very comfortable with this material and appears to have had considerable experience at the business end of analytics projects. The material centres around a 6-step, iterative analytics methodology which seemed very sensible to me and would be a good framework for many analytics projects. It emphasises that much of the work will go into the early Discovery phases (i.e. the ‘What the hell are we actually doing?” phase) and particularly the Data Preparation (the unsexy bit of data projects). All in all this seemed both sensible and easy material.

Things start getting technical in Module 3 which provides background technicals on statistical theory and R, the open-source statistics software. The course assumes a certain level of statistical background and programming ability and if you don’t have that this is where you might start to struggle. As an experienced programmer I found R no problem at all and thoroughly enjoyed both the programming and the statistics.

The real meat of the course is Modules 4 and 5. Module 4 is a big beast as it dives into a number of machine learning algorithms: Kmeans clustering, Apriori decision rules, linear and logistic regression, Naive Bayes and Decision Trees. Throw in some introductory Text Analysis and you have a massive subject base to cover. This particular part of the course is exceptionally well-written and pretty well presented. I’m not saying it’s perfect but it is hard to over-state how difficult it is to cover all this material effectively in a relatively short-space of time. Each of these algorithms is presented with use-cases, some theoretical background and insight, pros and cons, and a lab.

It should be acknowledged that analytics and big data projects require a considerable range of skills and this course provides a broad-brush overview of some of the more common techniques. Clearly you wouldn’t expect participation on this course to make you an expert Data Scientist any more than you would employ someone to program in Java or C just based on courses and exams taken. I certainly wouldn’t let someone loose to administer a production Documentum system without being very sure they had the tough experience to back up the certificates. Somewhere in the introduction to this course they make clear that the aim is to enable the you to become an effective participant in a big data analytics project; not necessarily as a data scientist but as someone who needs to understand both the process and the technicals. As far as this is the aim I think it is well met in Module 4.

Module 5 is an introduction to big data processing, in particular Hadoop and MADLib. I just want to make 1 point here. This is very much an overview and it is clear that the stance taken by the course is that a Data Scientist would be very concerned with technical details about which analytics methods to use and evaluate (the subject of module 4), however the processing side is just something that they need to be aware of. I suspect in real-life that this dichotomy is nowhere near as clear-cut.

Finally Module 6 is back to the high-level stuff of modules 1 and 2. Some useful stuff about how to write reports for project sponsors and other non-Data Scientists and dos and don’ts of diagrams and visualisations. If this all seems a bit obvious it’s amazing how often this is done badly. As the presenter points out it’s no good spending tons of time and effort producing great analytics if you aren’t able to effectively convince your stakeholders of your results and recommendations. This is so true. The big takeaways: don’t use 3D charts, and pie charts are usually a waste of ink (or screen real estate).

If I have one major complaint about the content it is that Feature Selection is not covered in any depth. It’s certainly there in places in module 4 but given that coming up with the right features to model on can have a huge impact on the predictive power of your model there is a case for specific focus.

So overall I think this was a worthwhile course as long as you don’t have unrealistic expectations of what you will achieve. Furthermore if you want to get full value from the labs you are going to have to invest some effort in installing software (R and Greenplum/Postgres) and ‘munging’ data sets to use.

Oh, by the way, I passed the exam!

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Thoughts on EMC On Demand

November 29, 2012 at 7:22 am | Posted in Architecture | 2 Comments
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I think EMC first started talking about On Demand at EMC World 2011. The idea is seductive and logical: rather than have to procure your own hardware, install and configure the software, and manage and administer the running system you get EMC to do it for you. The potential benefits are enormous.

First, economies of scale for running hardware in the same way as similar cloud-based offerings. By running on virtual machines and providing scale out options you potentially only have to pay for what you use.

Secondly, experts who can specialise in various aspects of installation, administration and troubleshooting. Furthermore there is an obvious incentive for EMC to focus on initiatives to simplify and automate tasks. Presumably that was the idea behind xMS, the deployment technology recently released with D7.

As a consequence of that last point it gives EMC a great way to collect usage data, bug information and performance insights.

Finally I see great potential in distributed content, allowing content to be replicated across data centres closer to the user. On-premise installations currently rely on solutions like BOCS or content replication to deliver better performance to users in remote offices. These can be tricky to configure without expert help and rely to a greater or lesser extent in having servers in locations where the organisation doesn’t want them.

So clearly I see big benefits, at least in theory. I have several thoughts around OnDemand some of which I hope to explore in future posts; in this post I want to talk about some potential drawbacks and how EMC might address them.

The first question people seem to ask is how will I be able to install and manage our customisations if EMC are managing everything? In fact I expect EMC to put significant limits on how much customisation you will be allowed in OnDemand environments. Which means that the arrival of xCP 2.0 with its ‘configure don’t code’ mentality (and D2s ui configurability) is serendipitous indeed. In fact I doubt OnDemand would really be workable for WDK-based apps like Webtop, DCM and Web Publisher; no-one runs these apps without considerable coded customisations.

Secondly, for some organisations moving content to the cloud will remain problematic as they will have regulatory requirements, or internal security needs, that mean certain types of content can’t reside in particular jurisdictions. This is by no means insurmountable and EMC will need plenty of distributed locations to satisfy some clients. However it does make the Amazon AWS model of ‘click and go’ server resourcing much more difficult for EMC.

Finally from a personnel perspective how will EMC deliver the necessary staffing of data centres if OnDemand really takes off? Running data centre operations is not a core business for EMC ( as far as I know). My assumption is that they won’t be building or running the hardware operations themselves but are partnering with existing companies that have the know how. However even setting up and staffing the software side is new to EMC. Does it have the existing capacity already or will it need to recruit? Or will much of OnDemand be farmed out to partners? Will they run 24×7 from the US or (more likely) use a follow the sun philosophy.

Time will obviously tell but I remain optimistic that OnDemand will be a success – it will depend heavily on the execution in what is a new area for EMC.

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