38 research outputs found
Reason Maintenance - State of the Art
This paper describes state of the art in reason maintenance with a focus on its future usage in the KiWi project. To give a bigger picture of the field, it also mentions closely related issues such as non-monotonic logic and paraconsistency. The paper is organized as follows: first, two motivating scenarios referring to semantic wikis are presented which are then used to introduce the different reason maintenance techniques
Reason Maintenance - Conceptual Framework
This paper describes the conceptual framework for reason maintenance developed as part of
WP2
Constructive Reasoning for Semantic Wikis
One of the main design goals of social software, such as wikis, is to
support and facilitate interaction and collaboration. This dissertation
explores challenges that arise from extending social software with
advanced facilities such as reasoning and semantic annotations and
presents tools in form of a conceptual model, structured tags, a rule
language, and a set of novel forward chaining and reason maintenance
methods for processing such rules that help to overcome the
challenges.
Wikis and semantic wikis were usually developed in an ad-hoc
manner, without much thought about the underlying concepts. A conceptual
model suitable for a semantic wiki that takes advanced features
such as annotations and reasoning into account is proposed. Moreover,
so called structured tags are proposed as a semi-formal knowledge
representation step between informal and formal annotations.
The focus of rule languages for the Semantic Web has been predominantly
on expert users and on the interplay of rule languages
and ontologies. KWRL, the KiWi Rule Language, is proposed as a
rule language for a semantic wiki that is easily understandable for
users as it is aware of the conceptual model of a wiki and as it
is inconsistency-tolerant, and that can be efficiently evaluated as it
builds upon Datalog concepts.
The requirement for fast response times of interactive software
translates in our work to bottom-up evaluation (materialization) of
rules (views) ahead of time – that is when rules or data change, not
when they are queried. Materialized views have to be updated when
data or rules change. While incremental view maintenance was intensively
studied in the past and literature on the subject is abundant,
the existing methods have surprisingly many disadvantages – they
do not provide all information desirable for explanation of derived
information, they require evaluation of possibly substantially larger
Datalog programs with negation, they recompute the whole extension
of a predicate even if only a small part of it is affected by a
change, they require adaptation for handling general rule changes.
A particular contribution of this dissertation consists in a set of
forward chaining and reason maintenance methods with a simple declarative
description that are efficient and derive and maintain information
necessary for reason maintenance and explanation. The reasoning
methods and most of the reason maintenance methods are described
in terms of a set of extended immediate consequence operators the
properties of which are proven in the classical logical programming
framework. In contrast to existing methods, the reason maintenance methods in this dissertation work by evaluating the original Datalog
program – they do not introduce negation if it is not present in the input
program – and only the affected part of a predicate’s extension is
recomputed. Moreover, our methods directly handle changes in both
data and rules; a rule change does not need to be handled as a special
case.
A framework of support graphs, a data structure inspired by justification
graphs of classical reason maintenance, is proposed. Support
graphs enable a unified description and a formal comparison of the
various reasoning and reason maintenance methods and define a notion
of a derivation such that the number of derivations of an atom is
always finite even in the recursive Datalog case.
A practical approach to implementing reasoning, reason maintenance,
and explanation in the KiWi semantic platform is also investigated. It
is shown how an implementation may benefit from using a graph
database instead of or along with a relational database
A Perfect Match for Reasoning, Explanation, and Reason Maintenance
Path query languages have been previously shown to com-
plement RDF rule languages in a natural way and have been used as
a means to implement the RDFS derivation rules. RPL is a novel path
query language specifically designed to be incorporated with RDF rules
and comes in three
avors: Node-, edge- and path-
avored expressions
allow to express conditional regular expressions over the nodes, edges, or
nodes and edges appearing on paths within RDF graphs. Providing reg-
ular string expressions and negation, RPL is more expressive than other
RDF path languages that have been proposed. We give a compositional
semantics for RPL and show that it can be evaluated efficiently, while
several possible extensions of it cannot
A Potpourri of Reason Maintenance Methods
We present novel methods to compute changes to materialized
views in logic databases like those used by rule-based reasoners.
Such reasoners have to address the problem of changing axioms in the
presence of materializations of derived atoms. Existing approaches have
drawbacks: some require to generate and evaluate large transformed programs
that are in Datalog - while the source program is in Datalog and
significantly smaller; some recompute the whole extension of a predicate
even if only a small part of this extension is affected by the change.
The methods presented in this article overcome these drawbacks and derive
additional information useful also for explanation, at the price of an
adaptation of the semi-naive forward chaining
Dependency Updates and Reasoning in KiWi
KiWi is a framework for semantic social software applica-
tions that combines the Wiki philosophy with Semantic Web technolo-
gies. Applications based on KiWi can therefore leverage i.a. reasoning
and versioning to follow both aspects and even go beyond existing tech-
nologies. For example, KiWi allows composition of content items, which
poses a challenge to the versioning system. In this paper we discuss ver-
sioning of composed content items and challenges related to reasoning in
collaborative social software, as both topics are concerned with updates
on the application state
A Perfect Match for Reasoning, Explanation, and Reason Maintenance
Path query languages have been previously shown to com-
plement RDF rule languages in a natural way and have been used as
a means to implement the RDFS derivation rules. RPL is a novel path
query language specifically designed to be incorporated with RDF rules
and comes in three
avors: Node-, edge- and path-
avored expressions
allow to express conditional regular expressions over the nodes, edges, or
nodes and edges appearing on paths within RDF graphs. Providing reg-
ular string expressions and negation, RPL is more expressive than other
RDF path languages that have been proposed. We give a compositional
semantics for RPL and show that it can be evaluated efficiently, while
several possible extensions of it cannot
Where the snags are : Looking into bird bones
AbstractA study of bird remains from the Koziarnia Cave (Poland) revealed the presence of nearly a dozen bony shreds (snags) projecting from the natural canals in bones; the snags were made of a material that accumulated during the Late Pleistocene. This paper describes this phenomenon and determines the most probable agent responsible for its occurrence by utilizing observations of snag microstructure, taphonomic analysis of bird assemblages from Koziarnia Cave, and surveys of collected bird remains (modern and fossilized). The presence of snag may be a good qualitative indicator of an agent responsible for the accumulation of bird bones at archeological sites and could be useful in future taphonomic studies.Abstract
A study of bird remains from the Koziarnia Cave (Poland) revealed the presence of nearly a dozen bony shreds (snags) projecting from the natural canals in bones; the snags were made of a material that accumulated during the Late Pleistocene. This paper describes this phenomenon and determines the most probable agent responsible for its occurrence by utilizing observations of snag microstructure, taphonomic analysis of bird assemblages from Koziarnia Cave, and surveys of collected bird remains (modern and fossilized). The presence of snag may be a good qualitative indicator of an agent responsible for the accumulation of bird bones at archeological sites and could be useful in future taphonomic studies
Predicting Compressive Strength of Cement-Stabilized Rammed Earth Based on SEM Images Using Computer Vision and Deep Learning
Predicting the compressive strength of cement-stabilized rammed earth (CSRE) using current testing machines is time-consuming and costly and may harm the environment due to the samples’ waste. This paper presents an automatic method using computer vision and deep learning to solve the problem. For this purpose, a deep convolutional neural network (DCNN) model is proposed, which was evaluated on a new in-house scanning electron microscope (SEM) image database containing 4284 images of materials with different compressive strengths. The experimental results show reasonable prediction results compared to other traditional methods, achieving 84% prediction accuracy and a small (1.5) oot Mean Square Error (RMSE). This indicates that the proposed method (with some enhancements) can be used in practice for predicting the compressive strength of CSRE samples