Research Groups

Diderot: A Parallel Domain-Specific Language for Image Analysis and Visualization – John Reppy

Diderot: A Parallel Domain-Specific Language for Image Analysis and Visualization

Abstract:
The analysis of structure in three-dimensional images is increasingly valuable for biomedical research and computational science. At the same time, the computational burden of processing images is increasing as devices produce images of higher resolution (e.g., typical CT scans have gone from 128^3 to roughly 512^3 resolutions). With the latest scanning technologies, it is also more common for the the values measured at each sample to be multi-dimensional rather than a single scalar, which further complicates implementing mathematically correct methods.

Diderot is a domain-specific language (DSL) for programming advanced 3D image visualization and analysis algorithms. These algorithms, such as volume rendering, fiber tractography, and particle systems, are naturally defined as computations over continuous tensor fields that are reconstructed from the discrete image data. Diderot combines a high-level mathematical programming notation based on tensor calculus with an abstract bulk-synchronous parallelism model. Diderot is designed to both enable rapid prototyping of new image analysis algorithms and high performance on a range of parallel platforms.

In this talk, I will give an overview of the design of Diderot and examples of its use. I will then describe aspects of its implementation with a focus on how we translate the notation of tensor calculus to efficient code. I will also briefly discuss the automated techniques we use to validate the correctness of the compilation process.

Diderot is joint work with Gordon Kindlmann, Charisee Chiw, Lamont Samuels, and Nick Seltzer.

Bio:
John Reppy is a Professor of Computer Science and a Senior Fellow of the Computation Institute at the University of Chicago. He received his Ph.D. from Cornell University in 1992 and spent the first eleven years of his career at Bell Labs in Murray Hill NJ. He has been exploring issues in language design and implementation since the late 1980’s, with a focus on higher-order, typed, functional languages. His work includes the invention of Concurrent ML and work on combining object-oriented and functional language features. His current research is on high-level languages for parallel programming, including the Diderot, Manticore, and Nessie projects.

Event details

  • When: 2nd April 2018 13:00 - 14:00
  • Where: Cole 1.33b
  • Format: Seminar

SRG Seminar: “On Engineering Unikernels” by Ward Jaradat

We have explored data coordination techniques that permit distributed systems to be constructed by interconnecting services. In such systems the network latency is often a problem. For example, large data volumes might have to be transmitted across the network if computation cannot be co-located close to data sources. One solution to this problem is the ability to deploy services in appropriate geographical locations and compose them together to create distributed ecosystems. Hence we seek to be able to deploy such services rapidly and dynamically enact and orchestrate them. However, this goal is hindered by the size of the deployments. Currently, virtual machine appliances that host such services on top of monolithic kernels are very large, thus are potentially slow to deploy as they may need to be transmitted across a network.

Our principles led us to take the route of re-engineering the standard software stack to create self-contained applications that are less-bloated and consequently much smaller based on Unikernels. Unikernels are compact library operating systems that enable a single application to be statically linked against a simple kernel that manages the underlying resources presented by a hypervisor. In this talk I will present Stardust – a specialised Unikernel that aims to support the deployment of application services based on the Java programming language.

Event details

  • When: 15th March 2018 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Seminar

St Andrews – University of Primorska co-tutelle in Computer Science

The University of St Andrews and Primorska are soon to agree to award a joint degree with the title of Doctor of Philosophy (on condition that the joint PhD study programme in Computer Science will gain accreditation of the Slovenian Quality Assurance Agency for Higher Education). This represents the culmination of many months of effort from Drs Matjaž Kljun, Klen Čopič Pucihar and Professor Aaron Quigley. Aaron and Matjaž first met at the UMAP conference in 2011 in Spain as mentor and mentee in the PhD doctoral program. Since then, Matjaž and Klen who undertook their PhDs in the University of Lancaster have returned to Slovenia to establish and exciting program of HCI research and development in the HICUP lab. In 2017 a program of international support (Slovenian/English) allowed them to invite Aaron to Slovenia for three weeks and this has resulted in a number of join grant submissions and the establishment of this co-tutelle program. We look forward to many years collaborating and we look forward to this new PhD student starting later this year.

VISSOFT 2018 Keynote by Professor Aaron Quigley

Aaron will be a keynote speaker at the IEEE VISSOFT 2018 conference later this year. “The sixth IEEE Working Conference on Software Visualization (VISSOFT 2018) builds upon the success of the previous four editions of VISSOFT, which in turn followed after six editions of the IEEE International Workshop on Visualizing Software for Understanding and Analysis (VISSOFT) and five editions of the ACM Symposium on Software Visualization (SOFTVIS). Software visualization is a broad research area encompassing concepts, methods, tools, and techniques that assist in a range of software engineering and software development activities. Covered aspects include the development and evaluation of approaches for visually analyzing software and software systems, including their structure, execution behaviour, and evolution.”

Mensch-und-Computer 2019 Keynote by Professor Aaron Quigley

Professor Aaron Quigley will be a keynote speaker at the Mensch-und-Computer conference 2019 in Hamburg Germany in September of 2019. This series of symposia takes place each year in different German-speaking countries. This is one of the largest HCI conferences in Europe each year with over 700 delegates from industry and academia. Usability Professionals and Scientists come together in a multi-track program with long papers, short contributions, demos, tutorials and workshops. Submissions are possible in German and English.

Compositional Coinduction with Sized Types – Dr. Andreas Abel

Abstract:

Formal languages and automata are taught to every computer science student.  However, the student will most likely not see the beautiful coalgebraic foundations, which use coindutive reasoning.

In this talk, I recapitulate how infinite tries can represent formal languages (sets of strings).  I explain Agda’s coinduction mechanism based on copatterns and sized types demonstrate that it allows an elegant representation of the usual language constructions like union, concatenation, and Kleene star, with the help of Brzozowski derivatives.

Event details

  • When: 16th February 2018 12:00 - 13:00
  • Where: Cole 1.33b
  • Format: Seminar

Simplifying ARM concurrency – Prof. Susmit Sarkar

ARM has a relaxed memory model, previously specified in informal prose for ARMv7 and ARMv8. Over time, and partly due to work building formal semantics for ARM concurrency, it has become clear that some of the complexity of the model is not justified by the potential benefits. In
particular, the model was originally non-multicopy-atomic: writes could
become visible to some other threads before becoming visible to all —
but this has not been exploited in production implementations, the
corresponding potential hardware optimisations are thought to have
insufficient benefits in the ARM context, and it gives rise to subtle
complications when combined with other ARMv8 features. The ARMv8
architecture has therefore been revised: it now has a multicopy-atomic
model. It has also been simplified in other respects, including more
straightforward notions of dependency, and the architecture now includes
a formal concurrency model.

This is work presented in POPL this year. I will also present some of
the background and context on relaxed memory which is absent from the
necessarily compressed talk format of POPL.

Event details

  • When: 22nd February 2018 12:00 - 13:00
  • Where: Cole 1.33a
  • Format: Talk

DLS: Functional Foundations for Operating Systems

Biography: Dr. Anil Madhavapeddy is a University Lecturer at the Cambridge Computer Laboratory, and a Fellow of Pembroke College where he is Director of Studies for Computer Science. He has worked in industry (NetApp, Citrix, Intel), academia (Cambridge, Imperial, UCLA) and startups (XenSource, Unikernel Systems, Docker) over the past two decades. At Cambridge, he directs the OCaml Labs research group which delves into the intersection of functional programming and systems, and is a maintainer on many open source projects such as OpenBSD, OCaml, Xen and Docker.

Timetable
9:30: Introduction by Professor Saleem Bhatti
9:35: Lecture 1
10:35: Break with tea and coffee
11:15: Lecture 2
12:15: Lunch (not provided)
14:00: Lecture 3
15:00: Close by Professor Simon Dobson

Lecture 1: Rebuilding Operating Systems with Functional Principles
The software stacks that we deploy across computing devices in the world are based on shaky foundations. Millions of lines of C code crammed into monolithic operating system kernels, mixed with layers of scheduling logic, wrapped in a hypervisor, and served with a dose of nominal security checking on the side. In this talk, I will describe an alternative approach to constructing reliable, specialised systems with a familiar developer experience. We will use modular functional programming to build several services such as a secure web server that have no reliance on conventional operating systems, and explain how to express their logic in a high level, functional fashion. By the end of it, everyone in the audience should be able to build their own so-called unikernels!

Lecture 2: The First Billion Real Deployments of Unikernels
Unikernels offer a path to a more sane basis for driving applications on hardware, but will they ever be adopted for real? For the past fifteen years, an intrepid group of adventurers have been developing the MirageOS application stack in the OCaml programming language. Along the way, it has been deployed in many unusual industrial situations that I will describe in this talk, starting with the Docker container stack, then moving onto the Xen hypervisor that drives billions of servers worldwide. I will explain the challenges of using functional programming in industry, but also the rewards of seeing successful deployments quietly working in mission-critical areas of systems software.

Lecture 3: Programming the Next Trillion Embedded Devices
The unikernel approach of compiling highly specialised applications from high-level source code is perfectly suited to programming the trillions of embedded devices that are making their way around the world. However, this raises new challenges from a programming language perspective: how can we run on a spectrum of devices from the very tiny (with just kilobytes of RAM) to specialised hardware? I will describe the new frontier of functional metaprogramming (programs which generate more programs) that we are using to compile a single application to many heterogenous devices, and a Git-like model to coordinate across thousands of nodes. I will conclude with by motivating the need for a next-generation operating system to power new exciting applications such as augmented and virtual reality in our situated environments, and remove the need for constant centralised coordination via the Internet.

Event details

  • When: 13th February 2018 09:30 - 15:15
  • Where: Byre Theatre
  • Series: Distinguished Lectures Series, Systems Seminars Series
  • Format: Distinguished lecture