Justin Tyler Wiley

Installing pre-requisites for successful Ruby install on Ubuntu via RVM

Tue, 10 Jan 2012 15:12:00 -0500

Since I am constantly forgetting to do this before compilation, I thought I would post about it in case it benefits others.

$ gem install rake

ERROR: Loading command: install (LoadError)
cannot load such file — zlib

Installing rvm and ruby requires various per-requisites, namely development libraries ruby builds against during compilation. The RVM site leads you towards installation via RVM package, which introduces a whole other set of sources. A better solution is installing the appropriate native packages beforehand.

XSendfile: critical for Rails 3.1 on Apache

Mon, 19 Sep 2011 18:23:33 -0400

After several hours troubleshooting my production Rails environment, I finally found out why images were not being served properly after an upgrade to 3.1: no XSendfile module. Rails 3.1/Sprockets apparently relies heavily on Apache’s XSendfile to serve assets, and without the module installed and configured, images will silently fail and browsers will display a missing image.

To enable under Ubuntu:

sudo apt-get install libapache2-mod-xsendfile
Add XSendFile On to your Apache vhost file
Add XSendFileAllowAbove on under the directory definition for your public folder

More details here.

A New Forum for Healthcare IT: StackExchange

Wed, 07 Sep 2011 20:47:06 -0400

I regularly contribute to StackOverflow, a free, community powered Q&A site, about once a week. Whenever I have a challenging IT question in a particular domain, I find StackOverflow or one of it’s fellow sites in the StackExchange network, to be the fastest, cheapest, easiest route to getting feedback or suggestions. The unique mix of reputation and rewards for answering questions seem to have engendered a community that is actively interested in posing technical questions, and answering them well.

And so I am excited to learn StackExchange is planning on expanding to a site that focuses on Healthcare IT related questions as well. I think this would be a great edition to the HIT community, and provide a reputable source for HIT related Q&A beyond what can currently be offered by the hodge-podge of forums and groups that exist today. The site is still in the planning and proposal state, everyone is welcome to check it out, and contribute.

When using Heroku, Postgres is a Must

Thu, 23 Jun 2011 17:57:00 -0400

Why does my application work in the local development environment, but not in production?

Heroku is an awesome service. It provides a stable platform and tools for quickly deploying applications to the cloud, and allows users to enjoy all the scaling benefits cloud infrastructure can provide. One gotcha I have experienced, however, is Heroku’s reliance on the Postgres database, instead of MySQL.

While researching Heroku I noticed this, but naively assumed that I could use MySQL for local development, and that any differences between these two databases would be relatively obvious, and that I could compensate on the backend. ”Surely” I remember thinking, “almost all of my database queries will be performed in Active Record, and so I’ll be protected from DB differences anyway.” Unfortunately, I was wrong.

Some portions of my application code required implementing a slightly tricky join with the aggregate function ‘avg’. The results of this ended up going into a vector.

Unfortunately, Active Record returns strings instead of floats or integers for aggregate functions in Postgres. This is obviously leads to problems if your app is expecting something it can calculate with, and in my case leading to a silent conversion to 0.0. The end result was an application that performed differently on production at Heroku than locally in my MySQL development environment, and several hours spent moving to Postgres locally.

Lesson learned. Postgres all the way.

Update: It turns out converting to Postgres and removing DatabaseCleaner calls from my spec_helper reduced spec time from 78.2 seconds to 38.75 seconds. 50% faster specs eases the pain.

While looking for a good way to visualize ActiveRecord models, I...

Mon, 09 May 2011 20:00:06 -0400

While looking for a good way to visualize ActiveRecord models, I stumbled upon Rails ERD. I followed the painless install process which is essentially involves adding a one-liner in bundler and installing Graphviz via the DMG, and fired off the associated Rails ERD rake task. 5 seconds later I had a readable, dynamically generated PDF of the database schema for my project. Hats off to Rolf Timmermans for this useful utility.

MMCi and Me

Tue, 01 Feb 2011 10:00:06 -0500

Last year I enrolled in a new graduate program being offered by the Fuqua School of Business at Duke University.

The Master of Management in Clinical Informatics (MMCi) degree is a “one-year Management in Clinical Informatics program is the only interdisciplinary management program of its kind in the United States—leveraging Duke’s world-renowned track record in medicine, business, and health informatics. Through access to the finest faculty and resources across health care, IT, and management education, students will acquire the knowledge and skills to merge technology and patient care and help improve human health.”

I am incredibly proud of my involvement with this exciting new program, and I recently shared the story of how I came to choose MMCi over other graduate school options. I hope that this post will be part of a larger series of articles for Healthcare IT Today, if you have any questions or comments about the series please feel free to contact me via the feedback link to the right.

Late last year drop.io was purchased by Facebook. I had been...

Wed, 26 Jan 2011 14:55:00 -0500

Late last year drop.io was purchased by Facebook. I had been using drop.io to provide a public “drop box” (not related to the other drop box service) where folks could upload files, as well as a (rarely used) chat area that lived at the bottom of the main page at justintylerwiley.com.

These canned services were really just the tip of the drop.io API stack iceberg, which was Google Wave-like in scope and technical complexity. Drop.io had some really talented and creative developers working for them and came up with a number of innovative features that as far as I know were never really fully utilized in the web community. They were one of the first to pioneer Javascript based XMPP transfer functionality, and I remember when Katie and I first ran across them in 2009 we were pretty convinced that we were seeing Web 3.0.

Dropbox and chat services have been discontinued, and I’m not sure what Facebook has in store for the team, but I hope it’s as original and interesting as drop.io.

After evaluating Dropbox for several months, I decided to go all...

Wed, 08 Dec 2010 20:36:00 -0500

After evaluating Dropbox for several months, I decided to go all in and sign-up for a paid account. Easy, seamless backup, sharing and syncing. It’s handled storing my school assignments flawlessly, allowing my documents to live through one catastrophic operating system upgrade snafu. Check it out via the link above (full disclosure: it’s a referral link, so apparently I get some space, and you do too).

Intel and GE create joint venture for IT Healthcare

Tue, 03 Aug 2010 23:09:15 -0400

Intel and GE create joint venture for IT Healthcare:

“Intel and GE have announced a joint healthcare venture that marks a major step in the progress of Intel’s healthcare IT efforts…The new Intel/GE spinoff company has yet to be named, but the two companies will split ownership of it 50/50. The company will combine GE Healthcare’s Home Health division and Intel’s Digital Health Group, and it will launch later this year pending regulatory approval.”

Last week I was lucky enough to be able to attend a presentation...

Fri, 16 Jul 2010 08:00:00 -0400

Last week I was lucky enough to be able to attend a presentation by Grant Ingersoll to the RTP Semantic Web Group on Apache Mahout. Mahout is set of technologies designed to tackle machine learning problems in various clever ways, one of which is by using Apache Hadoop (hence the name, Mahout apparently means “elephant driver”).

Grant did a great job explaining the use cases for Mahout, describing how Google news, Netflix recommendations, Amazon suggestions and virtually every other feature advanced web applications have come to rely on machine learning.

While HTML5 has been widely touted as “the future of the web”, I think it’s important to remember that the content has to come from somewhere, no matter how beautifully rendered, and that increasingly the content will be the result of inferences created by software like Mahout. This is yet more incentive for me to continue plowing through Algorithms of the Intelligent Web.

Grant also spoke briefly about his new book Taming Text, which is all about extracting inferences from blobs of text, which strikes me as a highly useful set of related techniques to have on hand, given the amount of data-munging typical software development jobs inevitably require.

Thanks to Phil Rhodes for putting together this excellent presentation.

As someone who gets gadget fever on a regular basis, I found...

Wed, 07 Jul 2010 22:44:00 -0400

As someone who gets gadget fever on a regular basis, I found OSNews’s article describing the state of computer “recycling”, or what passes for it, very disturbing. Low or no safety standards for workers, shell charity organizations, and complete disregard for the environmental impact of discarded toxic waste are the norm in the foreign countries that receive our mountains iTrash.

The article mentions legal solutions to fix regulatory loopholes that allow this to go on in the United States, but more importantly it makes a solid argument for using refurbished equipment. Something I will have to consider before wandering the isles at Best Buy.

These pictures are courtesy of Basel Action Network

“But when the memory controller moves back onto the CPU...

Fri, 11 Jun 2010 10:00:00 -0400

“But when the memory controller moves back onto the CPU die and takes the GPU with it, that’s going to give an instant, one-time boost to the overall platform’s performance and efficiency. In the case of both Intel and AMD, this boost should be large enough that, if you can hold off on your next laptop upgrade until next year, you should. These kinds of discontinuities, where a major, disruptive repartitioning of the standard system architecture drives a one-off performance boost, are quite rare. They’re worth holding out for if you can manage it.”

The oil continues to flow, and it does not bode well for life in...

Fri, 04 Jun 2010 10:59:00 -0400

The oil continues to flow, and it does not bode well for life in the Gulf. Based on studies at UNC of the Exxon Valdez in 2003, “…environmental consequences of the Exxon Valdez oil spill went far beyond the more than 250,000 seabirds, thousands of marine mammals and countless numbers of other coastal marine organisms killed in the first days, weeks and months.”

Come one, come all to the new Chapel Hill / Durham Peace Corps...

Thu, 03 Jun 2010 13:53:00 -0400

Come one, come all to the new Chapel Hill / Durham Peace Corps Meetup group! I’m not sure what direction the group will take, but I’m definitely excited to meet some other volunteers, and folks interested in volunteering.

Are Autism and Fraqile X Syndrome reversable? “Dozens of...

Fri, 14 May 2010 19:00:00 -0400

Are Autism and Fraqile X Syndrome reversable?

“Dozens of academic labs across the globe have since shown that small molecules designed to block the activity of mGluR5 have the same effect, reducing abnormalities in mice with the fragile X mutation. Those abnormalities include seizures, atypical rates of protein synthesis, and other molecular glitches…”These compounds have made remarkable changes in animal models of fragile X, rescuing abnormal synaptic connections,” says Hagerman. “We’re very hopeful it will do the same for humans.”

“HealthCampRDU aims to be a highly-collaborative,...

Thu, 06 May 2010 19:35:00 -0400

“HealthCampRDU aims to be a highly-collaborative, day-long conference with a focus on issues and opportunities related to the changing face of healthcare.”

Mobile Health “Augmented Reality” Workshop, May...

Thu, 06 May 2010 14:59:00 -0400

Mobile Health “Augmented Reality” Workshop, May 26

“After nearly 20 years behind closed doors in research labs, Augmented Reality is taking shape as the next major wave of Internet innovation, overlaying and infusing the physical world with digital media, information, and experiences. At IFTF, we already know that mobile technologies are changing the way we interact with our health today—and we believe that Augmented Reality will furher transform this interaction by enabling us to see and envision, in real time, the full impact of our health and lifestyle choices.”

Image source

Megabiblioteca

Fri, 30 Apr 2010 18:00:00 -0400

Megabiblioteca

"Your identity is too important to be owned by any one company."

Fri, 23 Apr 2010 18:00:00 -0400

"Your identity is too important to be owned by any one company.":

Facebook’s Open Graph protocol is interesting…and disturbing. It’s “open” in the sense that anyone can use it. It’s closed in the sense that it references only Facebook, requires a Facebook account, and Facebook will own all the inferences it can draw from the link graph. A Facebook controlled web makes a lot of sense from Mark Zuckerberg’s perspective, but not from mine.

Visualizing the Health Care Debate

Fri, 16 Apr 2010 15:46:00 -0400