Christof Buchbender

  • from 2023: "CCAT Data Center Manager" at University of Cologne
  • 2014-today: PostDoc at University of Cologne, Germany Projects: GREAT/SOFIA, NANTEN-2, HIFI-ICC, CCAT
  • 2009-2013: PhD Student /Astronomer on Duty at IRAM 30m, Granada, Spain
    Thesis: "The cold and dense interstellar medium of M 33"
  • 2008-2009: Diplom-Thesis at Max-Planck Institut for Radioastronomy, Bonn, Germany
    Thesis: "An In-depth Study of the Interstellar Medium in the Barred Spiral Galaxy NGC3627"
  • 2003-2009: Study of Physics at University of Bonn, Germany

Sessions

11-02
17:30
60min
Inter-operable Data and Compute for Astronomical Research
verbenajl, Christof Buchbender, Maksym

Background

Astronomical research increasingly requires access to datasets from multiple observatories and substantial computational resources. Among the challenges we face, two related problems particularly limit efficient use of available infrastructure. First, data often remains scattered across individual archives with limited cross-center access. While IVOA standards and FAIR principles provide a great foundation, researchers still spend significant effort downloading, organizing, and combining datasets manually.

Modern science platforms like that of Rubin Observatory show promising approaches. Initiatives like PUNCH and NFDI in Germany are developing access layers and federation approaches. New astronomical data centers are being established, such as the one for the CCAT observatory in Cologne or at the German Center for Astrophysics (DZA). However, we would benefit from community agreement and blueprints on practical implementation at the data center level. For example, building CCAT's data center in Cologne, we find ourselves collecting lessons learned and advice from many people rather
than following established blueprints.

Second, HPC resources are fragmented across institutions, often with bureaucratic access barriers. Taking our experience of developing the CCAT Data Center in Cologne as an example again: we face a change in policies of the funding agencies, that now require community use for large computing infrastructure, impeding us from requesting funding for local HPC resources for our data center. This shows that our specific use case is not well represented in these policies, not least because using external HPC resources involves complex user access procedures, software deployment difficulties, and priority conflicts that make seamless resource sharing impractical or at least very burdensome.

Objectives

This BOF will examine these inter-operability challenges from both perspectives and identify practical next steps. We distinguish this from IVOA efforts by focusing on operational implementation and resource sharing policies rather than technical protocols. The goal is to understand what must be implemented at the core level when designing data centers and science platforms to enable easier, less bureaucratic cooperation between centers and institutions.

Format

We propose splitting into two working groups - one examining data inter-operability between archives and platforms, the other exploring compute resource sharing across HPC centers. Each group will identify existing solutions, ongoing initiatives, and priority areas for development. We can also explore differences in approaches between countries and communities. Groups will reconvene to share findings and develop a joint summary document outlining concrete recommendations for the community.

Expected Outcomes

  • Overview of existing solutions and ongoing initiatives for data and compute inter-operability
  • Differences in approaches between countries and communities
  • Actions needed to improve inter-operability
  • Successful models and technical requirements
  • Policy considerations for enabling better resource sharing across astronomical centers
Building and operating science platforms and workflows in the Petabyte Era
Seminar Room 4
11-03
09:00
30min
Code Is Cheap, Judgement Is Not: Building Software and Systems We Can Trust with Agentic AI
Christof Buchbender

Modern AI tools have made code cheap to produce. Trust in the results
has not become cheap, and in science and critical systems it is essential. Without
trust, the speed that AI offers is not an advantage.

I lead a small team building the Data Center for the CCAT Observatory,
including the complete data life cycle after observations, from the
operations database and archive through the analysis workflows,
HPC infrastructure and data access frontend. We were early adopters of
AI tools and moved from consulting chat systems about implementation
details, to discussing architecture, to handing coding work completely
over to agentic AI. With a team size of two FTEs, this let us build more
of what I had envisioned for the data center, earlier and to a higher
standard. One example was a rewrite of our calibration software into a
working, parallelized Rust implementation in one week, with parity
against its predecessor and a substantial speedup. But our team was
skeptical this new code really calibrates the data reliably. Before
agentic AI tools the slow development and frequent discussions built
trust in the code, for both the developer and the team. Now, a fast
rewrite happens on one person's computer, and without precautions leaves
colleagues behind, and oneself with a tool of uncertain behavior on an
unfamiliar code base.

I will present the workflow I built for us to reach that trust without
giving up development speed. Its purpose is to keep humans and agents
working from the same understanding. We let the AI agents use
programming languages and frameworks that we know well. Where exact
results matter we create deterministic testing harnesses that we can
audit. Because AI sessions are ephemeral, I designed the workflow so
that machine-readable definitions force each session to leave clear
artifacts in well defined places: implementation plans, decision
records, and documentation. These artifacts inform and onboard
colleagues, give the next agent its context, and let us later understand
what we built and why. However, we noted that artifacts that satisfy the
agent are often unreadable for humans. We therefore invest in shaping
their language and aligning on a shared, defined vocabulary, so that the
documents can be understood without the context of the sessions or
native-level English. I will show what has worked for us, where it has
not, and what we are still doing about it.

Looking ahead, I am unsure where agentic AI will leave us as developers
and scientists. The calibration rewrite was fast, but only because I understood the old
software well after working with it for 10 years and we had a test suite. Work has been
offloaded before, for example we trusted libraries to do complex jobs,
however this is the first time that judgement can seemingly be offloaded
to AI. Before, this judgement could only be built by study, failure and
discussion. This leads to one central question I have: how does the next
generation acquire that judgement and experience if they never have to
earn it first?  Or do we hand judgement over altogether, willingly or not?

I am convinced that using AI agents for software engineering can improve
the science, and the support of it, tremendously, but only if we keep
people and our own judgement in the loop.

AI as tool for software engineering
Banquet Hall