7 research outputs found
Incorporating Stratified Negation into Query-Subquery Nets for Evaluating Queries to Stratified Deductive Databases
Most of the previously known evaluation methods for deductive databases are either breadth-first or depth-first (and recursive). There are cases when these strategies are not the best ones. It is desirable to have an evaluation framework for stratified DatalogN that is goal-driven, set-at-a-time (as opposed to tuple-at-a-time) and adjustable w.r.t. flow-of-control strategies. These properties are important for efficient query evaluation on large and complex deductive databases. In this paper, by incorporating stratified negation into so-called query-subquery nets, we develop an evaluation framework, called QSQNSTR, with such properties for evaluating queries to stratified DatalogN databases. A variety of flow-of-control strategies can be used for QSQNSTR. The generic evaluation method QSQNSTR for stratified DatalogN is sound, complete and has a PTIME data complexity
Logic Programming as Constructivism
The features of logic programming that
seem unconventional from the viewpoint of classical logic
can be explained in terms of constructivistic logic. We
motivate and propose a constructivistic proof theory of
non-Horn logic programming. Then, we apply this formalization
for establishing results of practical interest.
First, we show that 'stratification can be motivated in a
simple and intuitive way. Relying on similar motivations,
we introduce the larger classes of 'loosely stratified' and
'constructively consistent' programs. Second, we give a
formal basis for introducing quantifiers into queries and
logic programs by defining 'constructively domain
independent* formulas. Third, we extend the Generalized
Magic Sets procedure to loosely stratified and constructively
consistent programs, by relying on a 'conditional
fixpoini procedure
DATA-DRIVEN ANALYTICAL MODELS FOR IDENTIFICATION AND PREDICTION OF OPPORTUNITIES AND THREATS
During the lifecycle of mega engineering projects such as: energy facilities,
infrastructure projects, or data centers, executives in charge should take into account
the potential opportunities and threats that could affect the execution of such projects.
These opportunities and threats can arise from different domains; including for
example: geopolitical, economic or financial, and can have an impact on different
entities, such as, countries, cities or companies. The goal of this research is to provide
a new approach to identify and predict opportunities and threats using large and diverse
data sets, and ensemble Long-Short Term Memory (LSTM) neural network models to
inform domain specific foresights. In addition to predicting the opportunities and
threats, this research proposes new techniques to help decision-makers for deduction
and reasoning purposes. The proposed models and results provide structured output to
inform the executive decision-making process concerning large engineering projects
(LEPs). This research proposes new techniques that not only provide reliable timeseries
predictions but uncertainty quantification to help make more informed decisions.
The proposed ensemble framework consists of the following components: first,
processed domain knowledge is used to extract a set of entity-domain features; second,
structured learning based on Dynamic Time Warping (DTW), to learn similarity
between sequences and Hierarchical Clustering Analysis (HCA), is used to determine
which features are relevant for a given prediction problem; and finally, an automated
decision based on the input and structured learning from the DTW-HCA is used to
build a training data-set which is fed into a deep LSTM neural network for time-series
predictions. A set of deeper ensemble programs are proposed such as Monte Carlo
Simulations and Time Label Assignment to offer a controlled setting for assessing the
impact of external shocks and a temporal alert system, respectively. The developed
model can be used to inform decision makers about the set of opportunities and threats
that their entities and assets face as a result of being engaged in an LEP accounting for
epistemic uncertainty