I'm a Computer Science PhD from Indiana University, and part of the Database Lab. I defended my thesis on July 2011, with an official graduation date of September 2011. In November 2011, I will join Google as a Software Engineer.

My research is on structural indexes for XML databases, I work with my advisor Prof. Melanie Wu on the design and development of a new family of structural indices (the Trie indices). We follow a methodology that couples the partitions induced by fragments of the XPath algebra and those induced by the structural properties of an XML document to lead the design of our indexes.

Our results show that the Trie indices are capable of answering core XPath queries with arbitrarily complicated predicates using index-only plans and improving query performance in orders of magnitude over similar aproaches. The workload-aware indices we designed enhance query evaluation performance and alleviate the trade-off between space and performance.

We have also developed a workload-aware version of our indices that study how to leverage workload information to obtain better results while reducing index size.

For more details, check the Papers section below.

Dr. Ed Robertson led the Software Engineering courses at IU up until his retirement in 2009. In his courses, students went through a two semester project for a real client in the Bloomington community, trying to simulate an actual working environment as close as possible to an actual job, with managers from the Software Engineering Management class, weekly team meetings, logs, proper documentation, and everything CS graduates will find when they get a job.

I was the AI (Assistant Instructor) for four years, and it was a really fun course to be involved with. It was a lot of hard work, but students that have taken it keep saying it was worth it.

Refereed Publications

Yuqing Wu, Sofía Brenes, Hyungdae Yi. Workload-aware Trie Indices for XML. 18th ACM Conference on Information and Knowledge Management (CIKM), 2009.

Yuqing Wu, Sofía Brenes, Tejas Totade, Dhaval Damani, Shijin Joshua, Michel Salim. ASIC: Algebra-based Structural Indices Comparison. 18th ACM Conference on Information and Knowledge Management (CIKM), 2009.

Yuqing Wu, Namrata Lele, Rashmi Aroskar, Sharanya Chinnusamy, Sofía Brenes. XQGen - An Algebra-based XPath Query Generator for Micro-Benchmarking. 18th ACM Conference on Information and Knowledge Management (CIKM), 2009.

Sofía Brenes, Yuqing Wu, Dirk Van Gucht, Pablo Santa Cruz. Trie Indexes for Efficient XML Query Evaluation. 11th International Workshop on Web and Databases (WebDB), 2008.

Sofía Brenes and Yuqing Wu. Structural Summaries for Efficient XML Query Processing. EDBT PhD Workshop, 2008. Best Submission Award.

George H.L. Fletcher, Dirk Van Gucht, Yuqing Wu, Marc Gyssens, Sofía Brenes, Jan Paredaens. A Methodology for Coupling Fragments of XPath with Structural Indexes for XML Documents. 11th International Symposium on Database Programming Languages (DBPL), 2007.

Sofía Brenes and Alejandro Valerio. Case Based Concept Map Topology Counselor. 2nd International Conference on Concept Mapping (CMC), 2006.

David B. Leake, Ana Gabriela Maguitman, Thomas Reichherzer, Alberto J. Cañas, Marco M. Carvalho, Marco Arguedas, Sofía Brenes, Thomas C. Eskridge. Aiding Knowledge Capture by Searching for Extensions of Knowledge Models. 2nd International Conference on Knowledge Capture (K-CAP), 2003.

Technical Reports

Sofía Brenes, Yuqing Melanie Wu, Hyungdae Yi. Workload-aware Trie Indexes for XML. Technical Report 673. Computer Science Department. Indiana University, Bloomington.

Academic

• 2005 - 2011. PhD Computer Science. Indiana University.
• 2003 - 2005. MSc Computer Science. Indiana University.
• 1998 - 2002. BSc Computer Science Engineer. Instituto Tecnológico de Costa Rica.

Professional

• November 2011 - Present. Software Engineer. Google. Mountain View, CA.
• Fall 2009. Associate Instructor - Database Systems. Computer Science Department, Indiana University. Bloomington, IN.
• Fall 2005 - Spring 2009. Associate Instructor - Software Engineering. Computer Science Department, Indiana University. Bloomington, IN.
• May - August 2008. Software Engineering Intern. Google. Mountain View, CA.
• May - August 2007. Software Engineering Intern. Google. Mountain View, CA.
• August 2003 - May 2005. Research Associate. Pervasive Technology Labs at Indiana University. Bloomington, IN.
• July 2001 - July 2003. Visiting Research Associate. Institute for Human and Machine Cognition. Pensacola, FL.

Other

• Member of the National Honor Society for Informatics.
• No, I don't have a middle name. It's two last names.
• Pictures.
• This is home.