Mendeley Suggest: Engineering a Personalised Article Recommender System

1. Mendeley Suggest: Engineering a Personalised ArticleRecommender System Kris Jack, PhD Chief Data Scientist https://twitter.com/_krisjack

2. Overview➔ Whats Mendeley?➔ Whats Mendeley Suggest?➔ Computation Layer➔ Serving Layer ➔ Architecture ➔ Technologies ➔ Deployment➔ Conclusions

3. Whats Mendeley?

4. ➔ Mendeley is a platform that connects researchers, research data and apps Mendeley Open API

5. ➔ Mendeley is a platform that connects researchers, research data and apps Mendeley Open API➔ Startup company with ~20 R&D engineers

6. Whats Mendeley Suggest?

7. Use Case➔ Good researchers are on top of their game➔ Difficult with the amount being produced➔ There must be a technology that can help➔ Help researchers by recommending relevant research

8. Mendeley Suggest

9. Computation Layer

10. Mendeley Suggest

13. Running on Amazons Elastic Map Reduce On demand use and easy to cost

14. Computation Layer 1.5M Users, 50M Articles Mahouts Normalised Amazon Hours Performance No. Good Recommendations/10

15. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Normalised Amazon Hours Performance Costly & Good Cheap & Bad No. Good Recommendations/10 Cheap & Good

18. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K Normalised Amazon Hours 6K 5K 4K 3K 2K 1K 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

19. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K 2K 1K 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

20. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K Cust. item-based ➔ 2.4K, 1.5 2K 1K 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

21. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K -4.1K (63%) 4K Paritioners MR allocation 3K Cust. item-based ➔ 2.4K, 1.5 2K 1K 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

22. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K Cust. item-based ➔ 2.4K, 1.5 2K 1K 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

23. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K Cust. item-based ➔ 2.4K, 1.5 2K Orig. user-based 1K ➔ 1K, 2.5 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

24. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K Cust. item-based +1 (67%) ➔ 2.4K, 1.5 2K -1.4K Orig. user-based (58%) 1K ➔ 1K, 2.5 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

25. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K 3K Cust. item-based ➔ 2.4K, 1.5 2K Orig. user-based 1K ➔ 1K, 2.5 Cust. user-based ➔ 0.3K, 2.5 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

26. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K -4.1K (63%) 4K 3K Cust. item-based ➔ 2.4K, 1.5 2K Orig. user-based 1K 1K, 2.5 ➔ -0.7K Cust. user-based (70%) ➔0.3K, 2.5 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

27. Computation Layer 1.5M Users, 50M Articles Mahouts Costly & Bad Performance Costly & Good 7K +1 (67%) 6.5K, 1.5 Normalised Amazon Hours 6K Orig. item-based 5K 4K -6.2K (95%) 3K Cust. item-based ➔ 2.4K, 1.5 2K Orig. user-based 1K ➔ 1K, 2.5 Cust. user-based ➔ 0.3K, 2.5 0 0.5 10 1.5 2 2.5 3 Cheap & Bad No. Good Recommendations/10 Cheap & Good

28. Mahout as the ComputationLayer➔ Out of the box, didnt work so well for us➔ Needed to understand Hadoop better➔ Contributed patch back to community (user-user)➔ Next step, the serving layer...

29. Serving Layer

30. Architecture Mendeley Hadoop Cluster User Cascading Libraries Computation Layer

31. Architecture AWS Elastic Elastic Beanstalk DynamoDB Elastic Beanstalk Beanstalk Serving Layer Mendeley Hadoop Cluster User Map Reduce Libraries Computation Layer

32. Technologies➔ Spring dependency injection framework ➔ Context-wide integration testing is easy, including pre-loading of test data ➔ Allows other Spring features (cache, security, messaging)➔ Spring MVC 3.2.M1 ➔ Annotated controllers, type conversion for free ➔ Asynchronous Servlet 3.0 supports thread parking➔ AlternatorDB ➔ In-memory DynamoDB implementation for testing

33. Technologies Recommendation<K> LongRecommendation UuidRecommendationGroupRecommendation PersonRecommendation DocumentRecommendation➔ Build once, employ in several use cases

34. Deployment➔ AWS ElasticBeanstalk ➔ Managed, auto-scaling, health-checking .war container➔ Jenkins continuous integration (CI) server➔ Maven build tool (useful dependency management)➔ beanstalk-maven-plugin (push a button to deploy) ➔ Deploys to ElasticBeanstalk ➔ Replaces existing application version if required ➔ Zero downtime updates (tested at ~300ms) ➔ Triggered by Jenkins

35. Putting it all together... $$$➔ Real-time article recommendations for 2 million users➔ 20 requests per second➔ $65.84/month ➔ $34.24 ElasticBeanstalk ➔ $28.17 DynamoDB ➔ $2.76 bandwidth➔ $30 to update the computation layer periodically

36. Conclusions

37. Conclusions➔ Mendeley Suggest is a personalised article recommender➔ Built by small team for big data➔ Uses Mahout as computation layer ➔ Needs some love out of the box➔ Serves from AWS ➔ Reduces maintenance costs and is reliable➔ Intend to release Mendeley Suggest to all users this year

38. Were Hiring!➔ Data Scientist ➔ apply recommender technologies to Mendeleys data ➔ work on improving the quality of Mendeleys research catalogue ➔ starting in first quarter of 2013 ➔ 6 month secondment in KNOW Center, TU Graz, Austria as part of the EC FP7 TEAM project (http://team-project.tugraz.at/)➔ http://www.mendeley.com/careers/

39. www.mendeley.com