142,601 research outputs found
Restriccions d'integritat temporals en bases de dades deductives bitemporals
The aim of this report is to introduce a taxonomy of temporal
integrity constraints, focused on the bitemporal deductive database
area, to get a better understanding of why they are required, their
behavior and the best way to define them using first order logic. To
meet these goals, we have analyzed temporal integrity constraints
taxonomies existing on the temporal database area and deeply related
areas as multiversion databases. Thus, the mentioned legacy work has
been adapted and developed to cover the scope of the bitemporal
deductive databases.Postprint (published version
The Events method for temporal integrity constraint handling in bitemporal deductive databases
A bitemporal deductive database is a deductive database that supports valid and
transaction time. A temporal integrity constraint deals
with only valid time, only transaction time or both times. A set of facts to be
einserted and deleted in a bitemporal deductive database can
be done in a past, present or future valid time and at current transaction time.
The temporal integrity constraint handling in bitemporal
deductive databases causes that the maintenance of consistency becomes more
complex than another databases. The $events method$ for handling temporal integrity constraints.
Finally, we present the interaction between the above-mentioned conceptual and
representational data models.Postprint (published version
Temporal and Contextual Dependencies in Relational Data Modeling
Although a solid theoretical foundation of relational data modeling has existed for decades, critical reassessment from temporal requirements’ perspective reveals shortcomings in its integrity constraints. We identify the need for this work by discussing how existing relational databases fail to ensure correctness of data when the data to be stored is time sensitive. The analysis presented in this work becomes particularly important in present times where, because of relational databases’ inadequacy to cater to all the requirements, new forms of database systems such as temporal databases, active databases, real time databases, and NoSQL (non-relational) databases have been introduced. In relational databases, temporal requirements have been dealt with either at application level using scripts or through manual assistance, but no attempts have been made to address them at design level. These requirements are the ones that need changing metadata as the time progresses, which remains unsupported by Relational Database Management System (RDBMS) to date.
Starting with shortcomings of data, entity, and referential integrity in relational data modeling, we propose a new form of integrity that works at a more detailed level of granularity. We also present several important concepts including temporal dependency, contextual dependency, and cell level integrity. We then introduce cellular-constraints to implement the proposed integrity and dependencies, and also how they can be incorporated into the relational data model to enable RDBMS to handle temporal requirements in future. Overall, we provide a formal description to address the temporal requirements’ problem in relational data model, and design a framework for solving this problem. We have supplemented our proposition using examples, experiments and results
Explicit Clock Temporal Logic in Timing Constraints for Real-Time Systems
A form of explicit clock temporal logic (called TLrt) useful in specifying timing constraints on controller actions, a real-time database (rtdb) items, and constraints in a real-time constraint base (rtcb), is presented. Timing as well as other forms of constraints are stored in the rtcb. A knowledge-based approach to ensure the integrity of information in an rtdb is given. The rtcb is realized as a logic program called Constrainer, which is a historyless integrity checker for a real-time database. The consistency and integrity issues for an rtcb and rtdb are investigated. The formal bases for a temporally complete rtdb and knowledgeably complete controller are presented. A partial TLrt specification of a knowledgeable controller for a Gas Burner is given. An illustration of a rtdb and rtcb in the context of the sample real-time system is also given
Fuzzy and uncertain spatio-temporal database models : a constraint-based approach
In this paper a constraint-based generalised object-oriented database model is adapted to manage spatiotemporal information. This adaptation is based on the definition of a new data type, which is suited to handle both temporal and spatial information. Generalised constraints are used to describe spatio-temporal data, to enforce integrity rules on databases, to specify the formal semantics of a database scheme and to impose selection criteria for information retrieval
Penghasilan dan penilaian video pembelajaran (CD) bagi mata pelajaran Prinsip Ekonomi (BPA 1013) bertajuk permintaan dan penawaran di KUITTHO
Kajian ini dijaiankan untuk meniiai keberkesanan sebuah video pembeiajaran
(CD) mata peiajaran Prinsip Ekonomi (BPA 1013) bertajuk Permintaan dan Penawaran.
Bagi tujuan tersebut, sebuah video pembelajaran telah dihasilkan membantu pelajar
bagi memahami mata pelajaran berkenan semasa proses pengajaran dan pembelajaran
berlaku. Video pembelajaran yang dihasilkan ini kemudian dinilai dari aspek proses
pengajaran dan pembelajaran, minat dan persepsi responden terhadap ciri-ciri video
(audio dan visual). Seramai 60 orang pelajar semester 2 Sarjana Muda Sains
Pengurusan di Kolej Universiti Teknologi Tun Hussein Onn telah dipiih bagi membuat
penilaian kebolehgunaan produk ini sebagai alat bantuan mengajar di dalam kelas.
Semua data yang diperolehi kemudiannya dikumpulkan bagi dianalisis dengan
menggunakan perisian "SrarMfKM/ Pac/rageybr Rocaj/ Sb/'eace " (SPSS). Hasil dapatan
kajian yang dilakukan jelas menunjukkan video pengajaran yang dihasilkan dan dinilai
ini amat sesuai digunakan bagi tujuan memenuhi keperluan proses pengajaran dan
pembelajaran subjek ini di dalam kelas
Geospatial Narratives and their Spatio-Temporal Dynamics: Commonsense Reasoning for High-level Analyses in Geographic Information Systems
The modelling, analysis, and visualisation of dynamic geospatial phenomena
has been identified as a key developmental challenge for next-generation
Geographic Information Systems (GIS). In this context, the envisaged
paradigmatic extensions to contemporary foundational GIS technology raises
fundamental questions concerning the ontological, formal representational, and
(analytical) computational methods that would underlie their spatial
information theoretic underpinnings.
We present the conceptual overview and architecture for the development of
high-level semantic and qualitative analytical capabilities for dynamic
geospatial domains. Building on formal methods in the areas of commonsense
reasoning, qualitative reasoning, spatial and temporal representation and
reasoning, reasoning about actions and change, and computational models of
narrative, we identify concrete theoretical and practical challenges that
accrue in the context of formal reasoning about `space, events, actions, and
change'. With this as a basis, and within the backdrop of an illustrated
scenario involving the spatio-temporal dynamics of urban narratives, we address
specific problems and solutions techniques chiefly involving `qualitative
abstraction', `data integration and spatial consistency', and `practical
geospatial abduction'. From a broad topical viewpoint, we propose that
next-generation dynamic GIS technology demands a transdisciplinary scientific
perspective that brings together Geography, Artificial Intelligence, and
Cognitive Science.
Keywords: artificial intelligence; cognitive systems; human-computer
interaction; geographic information systems; spatio-temporal dynamics;
computational models of narrative; geospatial analysis; geospatial modelling;
ontology; qualitative spatial modelling and reasoning; spatial assistance
systemsComment: ISPRS International Journal of Geo-Information (ISSN 2220-9964);
Special Issue on: Geospatial Monitoring and Modelling of Environmental
Change}. IJGI. Editor: Duccio Rocchini. (pre-print of article in press
Coherent Integration of Databases by Abductive Logic Programming
We introduce an abductive method for a coherent integration of independent
data-sources. The idea is to compute a list of data-facts that should be
inserted to the amalgamated database or retracted from it in order to restore
its consistency. This method is implemented by an abductive solver, called
Asystem, that applies SLDNFA-resolution on a meta-theory that relates
different, possibly contradicting, input databases. We also give a pure
model-theoretic analysis of the possible ways to `recover' consistent data from
an inconsistent database in terms of those models of the database that exhibit
as minimal inconsistent information as reasonably possible. This allows us to
characterize the `recovered databases' in terms of the `preferred' (i.e., most
consistent) models of the theory. The outcome is an abductive-based application
that is sound and complete with respect to a corresponding model-based,
preferential semantics, and -- to the best of our knowledge -- is more
expressive (thus more general) than any other implementation of coherent
integration of databases
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