Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!Please note that this talk is on an unusual day and time, Friday, at 3:30pm.

title:

Databases are Categories 2: Refinements and Extensions. (slides,video)

speaker:

David Spivak

time:

3:30pm, Friday, 22 October 2010

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

About five months ago I gave a talk here at Galois called “Databases are categories.” The basic idea was that a database schema can be represented as a category C and its states can be represented as functors C–>Set. In this talk I’ll refine that notion a bit, explaining that schemas are better represented as sketches. I’ll also show how, within this model one can: deal with incomplete data; incorporate typing and calculated fields; and perform queries, define views, and migrate data between disparate schemas. That is, I’ll try to show that the categorical approach handles everything one might hope it would. Finally, I’ll discuss a linguistic version of categories, called “ologs,” and show how they may help to democratize information storage.

bio:

I received my PhD in mathematics from UC Berkeley in 2007; my thesis was in Algebraic Topology. For the next three years I was a post doc in the math department at the University of Oregon. During this time my focus moved toward using category theory to understand information and communication. This past summer (2010) I began a post doc in the math department at MIT. My main interest at the moment is in using category theory to bridge the gap between disparate academic fields, and to generally enhance our ability to record, process, and communicate information.

Monitoring Distributed Real-Time Systems: A Survey and Future DirectionsAlwyn Goodloe (NIA) and Lee Pike (Galois, Inc), NASA Langley Research Center, 2010.

• Paper download: .pdf
• Paper home

Runtime monitors have been proposed as a means to increase the reliability of safety-critical systems. In particular, we explore runtime monitors for distributed hard real-time systems, such as fault-tolerant data buses and control systems for avionics and spacecraft. This class of systems has had little attention from the monitoring community. We motivate the need for monitors by discussing examples of avionic systems failure. We then describe work in the field of runtime monitoring. We present potential monitoring architectures for distributed real-time systems, and then we discuss how those architectures might be used to monitor properties of real-time distributed systems.

Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!

title:

Application of Computer Algebra Techniques in Verification of Galois Field Multipliers: Potential + Challenges

speaker:

Priyank Kalla

time:

10:30am, Tuesday 12 October 2010

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

Applications in Cryptography require multiplication and exponentiation operations to be performed over Galois fields GF(2^k). Therefore, there has been quite an interest in the hardware design and optimization of such multipliers. This has led to impressive advancements in this area — such as the use of composite field decomposition techniques, use of Montgomery multiplication, among others.My research group has recently begun investigations in the verification of such Galois Field multipliers. Unfortunately, the word-length (k) in such multipliers can be very large: typically, k = 256. Due to such large word-lengths, verification techniques based on decision diagrams, SAT and contemporary SMT solvers are infeasible. We are exploring the use of Computer Algebra techniques, mainly Groebner bases theory, to tackle this problem. In this talk, we will see why Groebner bases techniques look promising, while at the same time also studying the challanges that have to be overcome.

bio:

Priyank Kalla recieved the Bachelors degree in Electronics engineering from Sardar Patel University in India in 1993; and Masters and PhD from University of Massachusetts Amherst in 1998 and 2002, respectively. Since 2002, he is a faculty member in the ECE Dept. at the Univ. of Utah. His research interests are in the general areas of Logic Synthesis and Design Verification. Over the past few years, he has been investigating the use of computer algebra techniques over finite integer rings (Z/mZ) and finite fields (GF(2^m)) for optimization and verification of arithmetic datapaths. He is a recepient of the NSF CAREER award and the ACM TODAES 2009 best paper award. For more information, visit http://www.ece.utah.edu/~kalla

Dr. Lee Pike’s short abstract revisiting fault-tolerance of cyclic redundancy checks (CRCs), expanding on the work of Driscoll et al.. It introduces the concepts of Schrödinger-Hamming weight and Schördinger-Hamming distance, and argues that under a fault model in which stuck-at-one-half or slightly-out-of-spec faults dominate, current methods for computing the fault detection of CRCs may be over-optimistic.

• Paper (PDF)
• Slides (PDF)
• Haskell simulation
• Paper home

Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!Please note the nonstandard day/time!

title:

Introduction to Logic Synthesis (slides, video)

speaker:

Alan Mishchenko, University of California, Berkeley

time:

10:30am, Friday 08 October 2010

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

The lecture describes the problems solved by logic synthesis. It presents functional representations and typical computations applied to Boolean networks, such as traversal, windowing, cut computation, simulation, Boolean reasoning. Presented next are And-Inverter Graphs (AIGs) that are increasingly used as a unifying representation for all problems. The lecture is finished by an overview of AIG-based solutions in synthesis, technology mapping, and formal verification.

bio:

Alan Mishchenko graduated from Moscow Institute of Physics and Technology, Moscow, Russia, in 1993, and received his Ph.D. degree from Glushkov Institute of Cybernetics, Kiev, Ukraine, in 1997. He has been a research scientist in the US since 1998.  Currently, Alan is an Associate Researcher at University of California, Berkeley.  His research interests are in developing computationally efficient methods for logic synthesis and verification.

Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!

title:

abcBridge: Functional interfaces for AIGs and SAT solving (slides, video)

presenter:

Edward Z. Yang

time:

10:30am, Tuesday, 24 August 2010

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

SAT solvers are perhaps the most under-utilized high-tech tools that the modern software engineer has at their fingertips. An industrial strength SAT solver can solve most human generated NP-complete problems in time for lunch, and there are many, many practical problem domains which involve NP-complete problems. However, a major roadblock to using a SAT solver in your every day routine is translating your problem into SAT, and then running it on a highly optimized SAT solver, which is probably implemented in C or C++ and not your usual favorite programming language.This talk is about the use, design and implementation of abcBridge, a set of Haskell bindings for ABC, a system for sequential synthesis and verification produced by the Berkeley Logic Synthesis and Verification Group. ABC looks at SAT solving from the following perspective: given two circuits of logic gates (ANDs and NOTs), are they equivalent? ABC is imperative C code: abcBridge provides a pure and type-safe interface for building and manipulating and-inverter graphs. We hope to release abcBridge soon as open source.

bio:

Edward Z. Yang is an undergraduate studying computer science at MIT. He has been interning at Galois over the summer and enjoying every second of it. His interests include blogging, functional programming and practical applications of computer science research. You can read his blog at http://blog.ezyang.com/

Galois is pleased to announce a new white paper entitled High Assurance Software Development, written by David Burke, Joe Hurd and Aaron Tomb.

The purpose of this paper is describe how to make software assurance a part of a science of security. Software assurance as practiced is a grab-bag of techniques, heuristics, and lessons learned from earlier failures. Given the importance of software to critical infrastructures (electricity, banking, medicine), this is an untenable situation; the smooth functioning of our society depends on this software, and we need a more rigorous foundation for assessments about the trustworthiness of these systems.

In this paper we present an evidence-based approach to high assurance, in which diverse development teams can communicate in a common language to tackle the challenges of developing secure systems. Furthermore, this framework supports formal inference techniques (in particular, a trust relationship analysis), so that we can use automated reasoning to deal with scalability issues. Perhaps most importantly, an evidence-based approach lets us tailor the tools that we bring to bear on each claim: formal methods: testing; configuration management; and so forth all have their place in an assurance argument. In the end, it’s all about deploying systems where the residual risk has been minimized, given finite resources and time. Understanding this and managing it effectively is what the science of security is all about.

Galois is pleased to host the following tech talk.  These talks are open to the interested public.  Please join us!

title:

Industrial Strength Distributed Explicit Model Checking

presenter:

John Erickson

time:

10:30am,  August 3rd, 2010

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

Abstract:

We present PReach, an industrial strength distributed explicit state model checker based on Murphi. The goal of this project was to develop a reliable, easy to maintain, scalable model checker that was compatible with the Murphi specification language. PReach is implemented in the concurrent functional language Erlang, chosen for its parallel programming elegance. We use the original Murphi front-end to parse the model description, a layer written in Erlang to handle the communication aspects of the algorithm, and also use Murphi as a back-end for state expansion and to store the hash table. This allowed a clean and simple implementation, with the core parallel algorithms written in under 1000 lines of code. This talk describes the PReach implementation including the various features that are necessary for the large models we target. We have used PReach to model check an industrial cache coherence protocol with approximately 30 billion states. To our knowledge, this is the largest number published for a distributed explicit state model checker. PReach has been released to the public under an open source BSD license.

bio:

John Erickson is a Design Engineer at Intel Hillsboro.  He graduated with his PhD in Computer Science from The University of Texas at Austin in 2008.  Currently he is working on the validation of uncore components in a 50+ core processor using a variety of formal and dynamic techniques. Past research interests include theorem proving with a focus on lemma generation and generalization in the context of induction.

Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!

title:

Towards a High-Assurance Runtime System: Certified Garbage Collection

presenter:

Andrew Tolmach

time:

10:30am, Tuesday, 29 June 2010.

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

It seems obvious that the reliability of critical software can be improved by using high-level, memory-safe languages (Haskell, ML, Java, C#, etc.). But most existing implementations of these languages rely on large, complex run-time systems coded in C. Using such an RTS leads to a large “credibility gap” at the heart of the assurance argument for the overall system. To fill this gap, we are working to build a new high-assurance run-time system (HARTS), using an approach grounded in machine-assisted verification, with an initial focus on providing certifiably correct garbage collection.This talk will describe a machine-certified framework for correct compilation and execution of programs in garbage-collected languages. Our framework extends Leroy’s Coq-certified Compcert compiler and Cminor intermediate language. We add a new intermediate language, GCminor, that supports GC’ed languages and has a proven semantics-preserving translation to assembly code. GCminor neatly encapsulates the interface between mutator and collector code, while remaining simple and flexible enough to be used with a wide variety of source languages and collector styles. Front ends targeting GCminor can be implemented using any compiler technology and any desired degree of verification, including full semantics preservation, type preservation, or informal trust. As an example application of our framework, we describe a compiler for Haskell that translates the GHC’s Core intermediate language to GCminor. (This is joint work with Andrew McCreight and Tim Chevalier.)

bio:

Andrew Tolmach has been a faculty member at Portland State University since receiving his Ph.D.in Computer Science from Princeton in 1992. His current research interests, pursued under the aegis of the PSU High Assurance Systems Programming (HASP) project, focus on high-assurance systems software development, in particular using formal verification. His past publications, mostly about functional languages, include work on operating systems in Haskell, garbage collection, compilation, debugger implementation, integration with logic languages, and lazy functional algorithms.

Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!

title:

Coverset Induction with Partiality and Subsorts: A Powerlist Case Study

presenter:

Joe Hendrix

time:

10:30am, Tuesday, 22 June 2010.

location:

Galois Inc.421 SW 6th Ave. Suite 300, Portland, OR, USA(3rd floor of the Commonwealth building)

abstract:

Many inductive theorem provers use induction schemes derived from the recursive calls in functions definitions. This widely-used strategy is called coverset induction in the context of algebraic specifications. One challenge in applying coverset induction is that it typically requires using a total recursive function, while many operations on data structures are only meaningful on some well-formed subset of their possible inputs.

In this talk, I’ll discuss a generalization of coverset induction to handle partial constructors and operations. The generalization is implemented in the Maude ITP, and used in an extensive case study involving powerlists — a data structure introduced by J. Misra to elegantly formalize parallel algorithms based on divide and conquer strategy. Powerlists are constructed by partial operations, and it has been a challenge to naturally reason about powerlists using a formal logic that only supports total operations. We show how theorems about powerlists can be elegantly proven using the generalized coverset induction scheme implemented in the Maude ITP.

bio:

Joe is a member of the technical staff at Galois, Inc. He is interested in developing tools for making software development easier and safer. He started out developing software for civil engineers to analyze the safety of bridge foundations. He worked on automated decision procedures during his PhD at the University of Illinois. Immediately prior to joining Galois, he developed software within Microsoft’s Trustworthy Computing Initiative.