Hi! I am Sander Valstar.
A Senior Software Engineer at Amazon working on LLM evaluations
A Senior Software Engineer at Amazon working on LLM evaluations
08/2021–now
08/2021–now
Developing high-performance web services and machine learning applications. Proven track record of leading cross-functional teams to deliver innovative solutions that optimize performance and reduce costs.
Tech lead: Led the creation of a new Java webservice that assists Alexa's internal LLMs in resolving data and performing calculations by leveraging Alexa’s finite-state transducers. Coordinated across 6 teams (8 SDEs, 2 scientists and 1 TPM) for 20 stakeholder teams. Responsible for design, planning, implementation, leadership updates and security review.
Tech lead: Led the project to add support for context-free grammars in NLU Engine for Alexa’s food ordering skills. Coordinated across 4 teams, 8 SDEs and 3 scientists. Raised critical security issues and spearheaded unblocking them. Responsible for design, planning, implementation, leadership updates and security review.
Cost reduction & performance improvement: Implemented client-side routing for Alexa's MicroInterpreterService. Rolled out the change in phases to all Alexa customers worldwide without any incident. The change led to a 90% reduction in traffic to our load balancing and routing stack, saving roughly $36,000 monthly in infrastructure costs.
11/2015–07/2017
11/2015–07/2017
Design and development of new services like Same Day Delivery, Sunday Delivery, and making a precise delivery date calculation for cross-dock items
Backend: Mainly using Java Spring to develop high performant and resilient webservices that use Oracle or Postgres databases
Frontend: Using AngularJS and Angular 2+ for client-side applications
20% Project: At bol.com I initiated the start-up of a group which provides tech trainings internally. I developed a Java Spring training myself and guided several senior developers in making trainings about their expertise. These trainings were then published in the "bol.com academy" which I developed as a 20% side project. The code for the academy was written in Go and the trainings were written in Asciidoc. All trainings have a continuous deployment pipeline to make sure they can be updated easily. Some trainings, including my Spring training, are open-sourced on Github. The academy was a great success, all new junior engineers at bol.com take several of the trainings on the bol.com academy as part of their onboarding process.
2017–2021
2017–2021
Advisors: William G. Griswold and Leo Porter
Research Focus: Software Engineering and CS Education
2013–2015
2013–2015
Advisor: Mike Y. Chen
Research Focus: Mobile Human Computer Interaction
2009–2013
2009–2013
Listed below are some examples of programming languages and technologies I have gained experience with through my work in software engineering and academic research:
At UC San Diego I conduct research in CS Education on how we can better prepare CS students for careers in industry. At National Taiwan University I conducted research in Mobile HCI.
For a complete overview of my published research, please visit my Google Scholar profile.
ICER '20
Sander Valstar, Caroline Sih, Sophia Krause-Levy, Leo Porter, William G. Griswold
Google
Scholar
@inproceedings{Valstar:2020:QuantitativeFacultyViews,
author = {Valstar, Sander and Sih, Caroline and Krause-Levy, Sophia and Porter, Leo and Griswold, William G.},
title = {A Quantitative Study of Faculty Views on the Goals of an Undergraduate CS Program and Preparing Students for Industry},
year = {2020},
booktitle = {Proceedings of the 2020 ACM Conference on International Computing Education Research},
series = {ICER '20}
}
ITiCSE '20
Sander Valstar, William G. Griswold, Leo Porter
@inproceedings{Valstar:2020:DevContainers,
author = {Valstar, Sander and Griswold, William G. and Porter, Leo},
title = {Using DevContainers to Standardize Student Development Environments: An Experience Report},
year = {2020},
booktitle = {Proceedings of the 2020 ACM Conference on Innovation and Technology in Computer Science Education},
series = {ITiCSE '20}
}
SIGCSE '20
Sander Valstar, Sophia Krause-Levy, Alexandra Macedo, William G. Griswold, Leo Porter
@inproceedings{Valstar:2020:FacultyViewsQualitative,
author = {Valstar, Sander and Krause-Levy, Sophia and Macedo, Alexandra and Griswold, William G. and Porter, Leo},
title = {Faculty Views on the Goals of an Undergraduate CS Education and the Academia-Industry Gap},
year = {2020},
booktitle = {Proceedings of the 51st ACM Technical Symposium on Computer Science Education},
series = {SIGCSE '20}
}
ICER '19 Doctoral Symposium
Sander Valstar
@inproceedings{Valstar:2019:ClosingTheGap,
author = {Valstar, Sander},
title = {Closing the Academia-Industry Gap in Undergraduate CS},
year = {2019},
booktitle = {Proceedings of the 2019 ACM Conference on International Computing Education Research},
series = {ICER '19}
}
SIGCSE '19
Sander Valstar, William G. Griswold, Leo Porter
@inproceedings{Valstar:2019:PrerequisiteProficiency, author = {Valstar, Sander and Griswold, William G. and Porter, Leo},
title = {The Relationship between Prerequisite Proficiency and Student Performance in an Upper-Division Computing Course},
year = {2019},
booktitle = {Proceedings of the 50th ACM Technical Symposium on Computer Science Education},
series = {SIGCSE '19}
}
ACM MM '15
Andries (Sander) Valstar, Minchieh Hsiu, Teyen Wu, Mike Y. Chen
@inproceedings{Valstar:2015:Giggler,
author = {Valstar, Andries and Hsiu, Min-Chieh and Wu, Te-Yen and Chen, Mike Y.},
title = {Giggler: An Intuitive, Real-Time Integrated Wireless In-Ear Monitoring and Personal Mixing System Using Mobile Devices},
year = {2015},
booktitle = {Proceedings of the 23rd ACM International Conference on Multimedia},
series = {MM '15}
}
Summer 2020
Spring 2020
Fall 2020
Fall 2020
I facilitate in-class paper discussions, and grade student paper reports and student group projects
Winter 2020
Winter 2020
I developed and lead the Android labs which introduced students to the concepts required to complete their course project
Fall 2019
Fall 2019
During this term I integrated my tech stack for auto grading student test quality into the C++ programming assignments. At the end of the term, the 415 students reported writing an average of 10.00 tests per assignment (median = 10, sd = 6.59).
Spring 2019
Spring 2019
I prepared the Android project to be used for the labs, graded lab assignments and readings
Winter 2020
Winter 2020
I developed and lead labs on a wide variety of topics, including: Android, Unit Testing, UI Testing, Mocking, Continuous Integration, and Firebase Test Lab
Fall 2018
Fall 2018
I developed homework- and programming assignments and lead discussion sessions, held office hours, and answered questions in lectures and on the course forum