16 research outputs found
Reasoning about Qualitative Direction and Distance between Extended Objects using Answer Set Programming
In this thesis, we introduce a novel formal framework to represent and reason
about qualitative direction and distance relations between extended objects
using Answer Set Programming (ASP). We take Cardinal Directional Calculus (CDC)
as a starting point and extend CDC with new sorts of constraints which involve
defaults, preferences and negation. We call this extended version as nCDC. Then
we further extend nCDC by augmenting qualitative distance relation and name
this extension as nCDC+. For CDC, nCDC, nCDC+, we introduce an ASP-based
general framework to solve consistency checking problems, address composition
and inversion of qualitative spatial relations, infer unknown or missing
relations between objects, and find a suitable configuration of objects which
fulfills a given inquiry.Comment: In Proceedings ICLP 2019, arXiv:1909.0764
Answer Set Programming Modulo `Space-Time'
We present ASP Modulo `Space-Time', a declarative representational and
computational framework to perform commonsense reasoning about regions with
both spatial and temporal components. Supported are capabilities for mixed
qualitative-quantitative reasoning, consistency checking, and inferring
compositions of space-time relations; these capabilities combine and synergise
for applications in a range of AI application areas where the processing and
interpretation of spatio-temporal data is crucial. The framework and resulting
system is the only general KR-based method for declaratively reasoning about
the dynamics of `space-time' regions as first-class objects. We present an
empirical evaluation (with scalability and robustness results), and include
diverse application examples involving interpretation and control tasks
Answer Set Programming for Qualitative Spatio-Temporal Reasoning: Methods and Experiments
We study the translation of reasoning problems involving qualitative spatio-temporal calculi into answer set programming (ASP). We present various alternative transformations and provide a qualitative comparison among them. An implementation of these transformations is provided by a tool that transforms problem instances specified in the language of the Generic Qualitative Reasoner (GQR) into ASP problems. Finally, we report on an experimental analysis of solving consistency problems for Allen\u27s Interval Algebra and the Region Connection Calculus with eight base relations (RCC-8)
Axiomatic systems and topological semantics for intuitionistic temporal logic
We propose four axiomatic systems for intuitionistic linear temporal logic
and show that each of these systems is sound for a class of structures based
either on Kripke frames or on dynamic topological systems. Our topological
semantics features a new interpretation for the `henceforth' modality that is a
natural intuitionistic variant of the classical one. Using the soundness
results, we show that the four logics obtained from the axiomatic systems are
distinct. Finally, we show that when the language is restricted to the
`henceforth'-free fragment, the set of valid formulas for the relational and
topological semantics coincide
A Trajectory Calculus for Qualitative Spatial Reasoning Using Answer Set Programming
Spatial information is often expressed using qualitative terms such as
natural language expressions instead of coordinates; reasoning over such terms
has several practical applications, such as bus routes planning. Representing
and reasoning on trajectories is a specific case of qualitative spatial
reasoning that focuses on moving objects and their paths. In this work, we
propose two versions of a trajectory calculus based on the allowed properties
over trajectories, where trajectories are defined as a sequence of
non-overlapping regions of a partitioned map. More specifically, if a given
trajectory is allowed to start and finish at the same region, 6 base relations
are defined (TC-6). If a given trajectory should have different start and
finish regions but cycles are allowed within, 10 base relations are defined
(TC-10). Both versions of the calculus are implemented as ASP programs; we
propose several different encodings, including a generalised program capable of
encoding any qualitative calculus in ASP. All proposed encodings are
experimentally evaluated using a real-world dataset. Experiment results show
that the best performing implementation can scale up to an input of 250
trajectories for TC-6 and 150 trajectories for TC-10 for the problem of
discovering a consistent configuration, a significant improvement compared to
previous ASP implementations for similar qualitative spatial and temporal
calculi. This manuscript is under consideration for acceptance in TPLP.Comment: Paper presented at the 34th International Conference on Logic
Programming (ICLP 2018), Oxford, UK, July 14 to July 17, 2018, 20 pages,
LaTeX, 16 figure