9042273
Tactic-Based Optimized Compilation of Functional Programs
Within a framework of correct code-generation from HOL-specifications, we present a particular instance concerned with the optimized compilation of a lazy language (called MiniHaskell) to a strict language (called MiniML). 
 
Both languages are defined as shallow embeddings into denotational semantics based on Scott's cpo's, leading to a derivation of the corresponding operational semantics in order to cross-check the basic definitions. 
 
On this basis, translation rules from one language to the other were formally derived in Isabelle/HOL. Particular emphasis is put on the optimized compilation of function applications leading to the side-calculi inferring e.g. strictness of functions. 
 
The derived rules were grouped and set-up as an instance of our generic, tactic-based translator for specifications to code.
11977605
Collage Grammars for Collision-Free Growing of Objects in 3D Scenes
In the real world, solid objects rarely collide without serious damage. We study collision-freeness in the context of collage grammars, which are picture- and scene-generating devices based on hyperedge replacement. We identify a type of collage grammars that generate only collision-free collages, and prove the undecidability of the problem whether an arbitrary collage grammar generates any collision-free collage. Moreover, we discuss collision avoidance in the derivation process as an appropriate tool for practical modelling purposes.
29605470
A Real-Time Low-Power Stereo Vision Engine Using Semi-Global Matching
Many real-time stereo vision systems are available on low-power platforms. They all either use a local correlation-like stereo engine or perform dynamic programming variants on a scan-line. However, when looking at high-performance global stereo methods as listed in the upper third of the Middlebury database, the low-power real-time implementations for these methods are still missing. We propose a real-time implementation of the semi-global matching algorithm with algorithmic extensions for automotive applications on a reconfigurable hardware platform resulting in a low power consumption of under 3W. The algorithm runs at 25Hz processing image pairs of size 750x480 pixels and computing stereo on a 680x400 image part with up to a maximum of 128 disparities.
15316733
Admissible and Restrained Revision
As partial justification of their framework for iterated belief revision Darwiche and Pearl convincingly argued against Boutilier's natural revision and provided a prototypical revision operator that fits into their scheme. We show that the Darwiche-Pearl arguments lead naturally to the acceptance of a smaller class of operators which we refer to as admissible. Admissible revision ensures that the penultimate input is not ignored completely, thereby eliminating natural revision, but includes the Darwiche-Pearl operator, Nayak's lexicographic revision operator, and a newly introduced operator called restrained revision. We demonstrate that restrained revision is the most conservative of admissible revision operators, effecting as few changes as possible, while lexicographic revision is the least conservative, and point out that restrained revision can also be viewed as a composite operator, consisting of natural revision preceded by an application of a "backwards revision" operator previously studied by Papini. Finally, we propose the establishment of a principled approach for choosing an appropriate revision operator in different contexts and discuss future work.
8567787
Modeling and Solving Semiring Constraint Satisfaction Problems by Transformation to Weighted Semiring Max-SAT
We present a variant of theWeighted Maximum Satisfiability Problem (Weighted Max-SAT), which is a modeling of the Semiring Constraint Satisfaction framework. We show how to encode a Semiring Constraint Satisfaction Problem (SCSP) into an instance of a propositional Weighted Max-SAT, and call the encoding Weighted Semiring Max-SAT (WS-Max-SAT). The clauses in our encoding are highly structured and we exploit this feature to develop two algorithms for solving WS-Max-SAT: an incomplete algorithm based on the well-known GSAT algorithm for Max-SAT, and a branch-and-bound algorithm which is complete. Our preliminary experiments show that the translation of SCSP into WS-Max-SAT is feasible, and that our branch-and-bound algorithm performs surprisingly well. We aim in future to combine the natural flexible representation of the SCSP framework with the inherent efficiencies of SAT solvers by adjusting existing SAT solvers to solve WS-Max-SAT.
1871739
Sydney OWL Syntax - towards a Controlled Natural Language Syntax for OWL 1.1
This paper describes a proposed new syntax that can be used to write and read OWL ontologies in Controlled Natural Language (CNL): a well-defined subset of the English language. Following the lead of Manchester OWL Syntax in making OWL more accessible for non-logicians, and building on the previous success of Schwitter’s PENG (Processable English), the proposed Sydney OWL Syntax enables two-way translation and generation of grammatically correct full English sentences to and from OWL 1.1 functional syntax. Used in conjunction with OWL tools, it is designed to facilitate ontology construction and editing by enabling authors to write an OWL ontology in a defined subset of English. It also improves readability and understanding of OWL statements or whole ontologies, by enabling them to be read as English sentences. It is hoped that by providing the option of an intuitive, easy to use English syntax which requires no specialized knowledge, the broader community will be far more likely to develop and benefit from Semantic Web applications. This paper is a discussion paper covering the scope, design, and examples of Sydney OWL Syntax in use, and the authors invite feedback on all aspects of the proposal via email to krr.sydneysyntax@cse.unsw.edu.au. Working drafts of the full specification are available at http://www.ics.mq.edu.au/~rolfs/sos.
18938665
Semantic Preferential Subsumption
We present a general preferential semantic framework for plausible subsumption in description logics, analogous to the KLM preferential semantics for propositional entailment. We introduce the notion of ordered interpretations for description logics, and use it to define two mutually dual non-deductive subsumption relations ***⊑ and ***⊑*. We outline their properties and explain how they may be used for inductive and abductive reasoning respectively. We show that the preferential semantics for subsumption can be reduced to standard semantics of a sufficiently expressive description logic. This has the advantage that standard DL algorithms can be extended to reason about our notions of plausible subsumption.