Machine Learning: The Art of Explore vs. Exploit – SXSW Recap

Session by Oscar Celma (Pandora)
March 11, 2017

Pandora’s mission: be the effortless source of personalized music enjoyment and discovery

Some mind blowing statistics at Pandora

75M monthly average users
24 hours of listening per month
75B thumbs-up
12B stations created
98% of artists spinning every month

How does Pandora decide what to play next?

Content based algorithm: music genome data
Collective intelligence: mining user behavior
Personalized filtering: your thumbs up and skips
Ensemble recommender: piece together output from 75 different algorithms

Challenges: balance familiar with unfamiliar

Exploit: play awesome music now. Tomorrow? Who cares. Don’t play music I don’t like.
Explore: play something risky. Learning what to play. Don’t play too many WTF (“what the freakommendation” – Paul Lamere“).

Novelty versus relevance

Exploit: low novelty, high relevance
Explore: high novelty, high relevance
Popular: low novelty and low relevance
Risky: high novelty, low relevance

How does Pandora test new ideas?

  1. Dream idea
  2. Experiment in small group (1% of users)
  3. If successful, roll out 6-12 months later

Metrics: did it bring new listeners? Did it avoid churn? Did they listen for longer?

Retention: time spent listening, active days

Activity: thumbs, skips, create new stations

Pandora’s Tech Stack (some of it)

Memcache, Redis, Python, Java, Scala, Hive, Spark, PostgreSQL, Hadoop (HDFS)



Founder Counseling: 7 Steps to Founder Success – SXSW Recap

Session by David Mandell (PivotDesk), Jenny Fielding (TechStars), and Nicole Glaros (TechStars)
March 11, 2017

65% of startups fail due to people issues. It doesn’t have to be that way!

1. Cofounder issues

  • Know who you’re going into business with
  • Learn how to take ownership of problems – “it wasn’t what he was saying, it was how I was hearing it”
  • Equity split: any animosity will grow over time
    • Vesting: Get it right at the start. Protects founders, not punishs. Investors would set this up anyway.
    • Split correctly when everyone is feeling good
    • Venture Deals (book)
  • Cofounder dynamics affect culture for the rest of the company
  • Difficult Conversations (book)

2. Find great mentors

  • Mental / emotional support
  • Who you can talk to even when you can’t talk to anyone else
  • Someone you can be vulnerable with
  • Pro tip: don’t call them a mentor (at first)

3. Intellectual honesty

  • “Shit that scares me to death” portion of quarterly board update. Shows you’re trying to be real. What’s being done to address the issues? Maybe your investors have insights.
  • Honesty with self

4. Direct feedback

  • Not become defensive when receiving feedback
  • Usually given by people who care about you and your business

5. Right investors

  • Understand their motivation and goals
  • Can make your life a living hell if they want to
  • If you receive multiple term sheets, go after best fit, not best valuation
  • Accelerator? Do it as early as you can. Helps plug holes in your business. Talk to alumni from the accelerator to get a preview

6. Passion

  • Were your born for this?
  • Early on: enthusiasm & passion > skill
  • Scaling the business: skills matter more

7. Self improvement and insatiable curiosity

  • Always ask what you could be doing better

Fierce Conversations – SXSW Recap

Session by Susan Scott, Author of Fierce Conversations: Achieving Success at Work and in Life One Conversation at a Time
March 10, 2017

This was one of my favorite sessions at SXSW 2017. I will be buying Susan’s new edition of Fierce Conversations when it hits the bookstores May 2. Mark your calendars.

As we continue to see technology accelerate at an exponential pace, the human element remains largely the same. There is no Moore’s Law governing human-to-human interaction, yet many of us invest far too little time here.

As a software developer its easy to obsess over building a resume lined with cutting edge technologies or the latest tech fad. But what about building the relationships around us? How brilliant could we be if we don’t have the emotional capital to share it?

Susan proposes we do this one conversation at a time, where the relationship is the sum of conversations shared or the conversations missed. As Susan points out, “The conversation is the relationship. How we spend our days is how we spend our lives”.

How do we come out from behind ourselves and make ourselves real? Fierce conversations serve one or more of these functions:

  1. Interrogate reality
  2. Provoke learning
  3. Tackle and resolve tough challenges
  4. Enrich relationships

“The person who can describe reality without assigning blame will always emerge the leader”

D2Audio: Year in review

Its that time of year…clean up and update the ‘ol LinkedIn profile.  Since I changed from the D2Audio group to the Zilker Labs (power management) group, I wanted to make sure I wrote a thorough summary of my time at D2Audio while it was still fresh.  Here it goes:

Software developer and audio engineer for Audio Canvas III

What is Audio Canvas III?  Audio Canvas III empowers engineers to create custom firmware for Intersil’s class D audio amplifiers.  With real time parameter communication and innovative visualizations, Canvas allows the engineer to see and hear the sound change instantly, improving efficiency at every stage of the design cycle.    


Screenshot: Audio Canvas III signal flow, complete with message viewer, block library, frequency response graph, and controls

Developed new features for D2Audio Canvas III
* Link new audio blocks into system and create custom visualizations and UI for algorithms like FIR & biquad filters, Dolby Virtual Speaker, reverb, dither, PWM timing, harmonics
* Create responsive and intuitive user interface in multi-threaded environment
* Implement project persistence using encrypted XML
* Designed custom UI panels, navigation, menus, custom widgets
* Performed extensive testing using test scripts
Skills and tools:
* Java: Sun Certified Java programmer (SCJP 6)
    – Swing/AWT
    – Java 2D
    – Encryption
    – SAX (XML encoding and parsing)
* Motorola 56300 assembly, compiler, COFF file conversion
* R&D: Octave + DSP package
* Build: Ant, Nullsoft Scriptable Install System
* Windows XP: batch files, registry edit, command line
* Software lifecycle: version control, Agile-like project management
* Lab skills: Audio Precision, oscilloscope, soldering

Very cool app! Freemind

Ever had so many ideas and thoughts going through your head that its hard to sort them out? I’m pretty sure that’s why I’m such a spaz. Until I found this app.

So we all remember grade school writing. “The Writing Process”, they dubbed it. It was that redundant system of brainstorm, draft, edit, revise, draft… I used to hate drafts. Nothing worse than hearing “third drafts are due Wednesday.”

But there is good from this. Not the drafts, but the brainstorming. They would have us make these little cluster diagrams or outlines, little nodes with big ideas connected to sub-nodes with details and specifics. This high level heuristic approach really does help create good writing, or planning for that matter. This method captures how the human mind works.

Check out this example below. Instead of studying for my final exam (ima put the D in DSP) I made this cluster of ideas for how I want to spend my time this summer. It’s no where near complete, but it help me cluster my thoughts and ideas together in a constructive manner. Give this app a whirl, its free and great!