183 research outputs found
A TEMPORAL RELATIONAL ALGEBRA AS A BASIS FOR TEMPORAL RELATIONAL COMPLETENESS
We define a temporal algebra that is applicable to any
temporal relational data model supporting discrete linear
bounded time. This algebra has the five basic
relational algebra operators extended to the temporal
domain and an operator of linear recursion. We
show that this algebra has the expressive power of a
safe temporal calculus based on the predicate temporal
logic with the until and since temporal operators.
In [CrC189], a historical calculus was proposed as a
basis for historical relational completeness. We propose
the temporal algebra defined in this paper and
the equivalent temporal calculus as an alternative basis
for temporal relational completeness.Information Systems Working Papers Serie
Content-based Video Retrieval
no abstract
Case Adaptation with Qualitative Algebras
This paper proposes an approach for the adaptation of spatial or temporal
cases in a case-based reasoning system. Qualitative algebras are used as
spatial and temporal knowledge representation languages. The intuition behind
this adaptation approach is to apply a substitution and then repair potential
inconsistencies, thanks to belief revision on qualitative algebras. A temporal
example from the cooking domain is given. (The paper on which this extended
abstract is based was the recipient of the best paper award of the 2012
International Conference on Case-Based Reasoning.
Hop and HipHop : Multitier Web Orchestration
Rich applications merge classical computing, client-server concurrency,
web-based interfaces, and the complex time- and event-based reactive
programming found in embedded systems. To handle them, we extend the Hop web
programming platform by HipHop, a domain-specific language dedicated to
event-based process orchestration. Borrowing the synchronous reactive model of
Esterel, HipHop is based on synchronous concurrency and preemption primitives
that are known to be key components for the modular design of complex reactive
behaviors. HipHop departs from Esterel by its ability to handle the dynamicity
of Web applications, thanks to the reflexivity of Hop. Using a music player
example, we show how to modularly build a non-trivial Hop application using
HipHop orchestration code.Comment: International Conference on Distributed Computing and Internet
Technology (2014
Content-based Video Retrieval by Integrating Spatio-Temporal and Stochastic Recognition of Events
As amounts of publicly available video data grow the need to query this data efficiently becomes significant. Consequently content-based retrieval of video data turns out to be a challenging and important problem. We address the specific aspect of inferring semantics automatically from raw video data. In particular, we introduce a new video data model that supports the integrated use of two different approaches for mapping low-level features to high-level concepts. Firstly, the model is extended with a rule-based approach that supports spatio-temporal formalization of high-level concepts, and then with a stochastic approach. Furthermore, results on real tennis video data are presented, demonstrating the validity of both approaches, as well us advantages of their integrated us
Time management situation assessment (TMSA)
TMSA is a concept prototype developed to support NASA Test Directors (NTDs) in schedule execution monitoring during the later stages of a Shuttle countdown. The program detects qualitative and quantitative constraint violations in near real-time. The next version will support incremental rescheduling and reason over a substantially larger number of scheduled events
On Completeness of Historical Relational Query Languages
Numerous proposals for extending the relational data model to incorporate the temporal
dimension of data have appeared in the past several years. These proposals have differed
considerably in the way that the temporal dimension has been incorporated both into the
structure of the extended relations of these temporal models, and consequently into the
extended relational algebra or calculus that they define. Because of these differences it
has been difficult to compare the proposed models and to make judgments as to which of
them might in some sense be equivalent or even better. In this paper we define the notions of
temporally grouped and temporally ungrouped historical data models and propose two
notions of historical reIationa1 completeness, analogous to Codd's notion of relational
completeness, one for each type of model. We show that the temporally ungrouped models
are less expressive than the grouped models, but demonstrate a technique for extending the
ungrouped models with a grouping mechanism to capture the additional semantic power
of temporal grouping. For the ungrouped models we define three different languages, a
temporal logic, a logic with explicit reference to time, and a temporal algebra, and show
that under certain assumptions all three are equivalent in power. For the grouped models
we define a many-sorted logic with variables over ordinary values, historical values, and
times. Finally, we demonstrate the equivalence of this grouped calculus and the ungrouped
calculus extended with a grouping mechanism. We believe the classification of historical
data models into grouped and ungrouped provides a useful framework for the comparison
of models in the literature, and furthermore the exposition of equivalent languages for each
type provides reasonable standards for common, and minimal, notions of historical relational
completeness.Information Systems Working Papers Serie
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