461,019 research outputs found
Research issues in real-time database systems
Cataloged from PDF version of article.Today's real-time systems are characterized by managing large volumes of data.
Efficient database management algorithms for accessing and manipulating data are
required to satisfy timing constraints of supported applications. Real-time database
systems involve a new research area investigating possible ways of applying database
systems technology to real-time systems. Management of real-time information through
a database system requires the integration of concepts from both real-time systems and
database systems. Some new criteria need to be developed to involve timing constraints
of real-time applications in many database systems design issues, such as
transaction/query processing, data buffering, CPU, and IO scheduling. In this paper, a
basic understanding of the issues in real-time database systems is provided and the
research efforts in this area are introduced. Different approaches to various problems of
real-time database systems are briefly described, and possible future research directions
are discussed
Research issues in real-time database systems. Survey paper
Today's real-time systems are characterized by managing large volumes of data. Efficient database management algorithms for accessing and manipulating data are required to satisfy timing constraints of supported applications. Real-time database systems involve a new research area investigating possible ways of applying database systems technology to real-time systems. Management of real-time information through a database system requires the integration of concepts from both real-time systems and database systems. Some new criteria need to be developed to involve timing constraints of real-time applications in many database systems design issues, such as transaction/query processing, data buffering, CPU, and IO scheduling. In this paper, a basic understanding of the issues in real-time database systems is provided and the research efforts in this area are introduced. Different approaches to various problems of real-time database systems are briefly described, and possible future research directions are discussed. © 1995
Data based predictive control: Application to water distribution networks
In this thesis, the main goal is to propose novel data based predictive
controllers to cope with complex industrial infrastructures such as water
distribution networks. This sort of systems have several inputs and out-
puts, complicate nonlinear dynamics, binary actuators and they are usually
perturbed by disturbances and noise and require real-time control implemen-
tation. The proposed controllers have to deal successfully with these issues
while using the available information, such as past operation data of the
process, or system properties as fading dynamics.
To this end, the control strategies presented in this work follow a predic-
tive control approach. The control action computed by the proposed data-
driven strategies are obtained as the solution of an optimization problem
that is similar in essence to those used in model predictive control (MPC)
based on a cost function that determines the performance to be optimized.
In the proposed approach however, the prediction model is substituted by
an inference data based strategy, either to identify a model, an unknown
control law or estimate the future cost of a given decision. As in MPC, the
proposed strategies are based on a receding horizon implementation, which
implies that the optimization problems considered have to be solved online.
In order to obtain problems that can be solved e ciently, most of the
strategies proposed in this thesis are based on direct weight optimization
for ease of implementation and computational complexity reasons. Linear
convex combination is a simple and strong tool in continuous domain and
computational load associated with the constrained optimization problems
generated by linear convex combination are relatively soft. This fact makes
the proposed data based predictive approaches suitable to be used in real
time applications.
The proposed approaches selects the most adequate information (similar
to the current situation according to output, state, input, disturbances,etc.),
in particular, data which is close to the current state or situation of the
system. Using local data can be interpreted as an implicit local linearisation
of the system every time we solve the model-free data driven optimization
problem. This implies that even though, model free data driven approaches
presented in this thesis are based on linear theory, they can successfully deal
with nonlinear systems because of the implicit information available in the
database.
Finally, a learning-based approach for robust predictive control design for
multi-input multi-output (MIMO) linear systems is also presented, in which
the effect of the estimation and measuring errors or the effect of unknown
perturbations in large scale complex system is considered
Conceptual Modelling and The Quality of Ontologies: Endurantism Vs. Perdurantism
Ontologies are key enablers for sharing precise and machine-understandable
semantics among different applications and parties. Yet, for ontologies to meet
these expectations, their quality must be of a good standard. The quality of an
ontology is strongly based on the design method employed. This paper addresses
the design problems related to the modelling of ontologies, with specific
concentration on the issues related to the quality of the conceptualisations
produced. The paper aims to demonstrate the impact of the modelling paradigm
adopted on the quality of ontological models and, consequently, the potential
impact that such a decision can have in relation to the development of software
applications. To this aim, an ontology that is conceptualised based on the
Object-Role Modelling (ORM) approach (a representative of endurantism) is
re-engineered into a one modelled on the basis of the Object Paradigm (OP) (a
representative of perdurantism). Next, the two ontologies are analytically
compared using the specified criteria. The conducted comparison highlights that
using the OP for ontology conceptualisation can provide more expressive,
reusable, objective and temporal ontologies than those conceptualised on the
basis of the ORM approach
Pervasive computing at tableside : a wireless web-based ordering system
Purpose – The purpose of this paper is to introduce a wireless web-based ordering system called iMenu in the restaurant industry. Design/methodology/approach – By using wireless devices such as personal digital assistants and WebPads, this system realizes the paradigm of pervasive computing at tableside. Detailed system requirements, design, implementation and evaluation of iMenu are presented.Findings – The evaluation of iMenu shows it explicitly increases productivity of restaurant staff. It also has other desirable features such as integration, interoperation and scalability. Compared to traditional restaurant ordering process, by using this system customers get faster and better services, restaurant staff cooperate more efficiently with less working mistakes, and enterprise owners thus receive more business profits. Originality/value – While many researchers have explored using wireless web-based information systems in different industries, this paper presents a system that employs wireless multi-tiered web-based architecture to build pervasive computing systems. Instead of discussing theoretical issues on pervasive computing, we focus on practical issues of developing a real system, such as choosing of web-based architecture, design of input methods in small screens, and response time in wireless web-based systems.<br /
TLAD 2010 Proceedings:8th international workshop on teaching, learning and assesment of databases (TLAD)
This is the eighth in the series of highly successful international workshops on the Teaching, Learning and Assessment of Databases (TLAD 2010), which once again is held as a workshop of BNCOD 2010 - the 27th International Information Systems Conference. TLAD 2010 is held on the 28th June at the beautiful Dudhope Castle at the Abertay University, just before BNCOD, and hopes to be just as successful as its predecessors.The teaching of databases is central to all Computing Science, Software Engineering, Information Systems and Information Technology courses, and this year, the workshop aims to continue the tradition of bringing together both database teachers and researchers, in order to share good learning, teaching and assessment practice and experience, and further the growing community amongst database academics. As well as attracting academics from the UK community, the workshop has also been successful in attracting academics from the wider international community, through serving on the programme committee, and attending and presenting papers.This year, the workshop includes an invited talk given by Richard Cooper (of the University of Glasgow) who will present a discussion and some results from the Database Disciplinary Commons which was held in the UK over the academic year. Due to the healthy number of high quality submissions this year, the workshop will also present seven peer reviewed papers, and six refereed poster papers. Of the seven presented papers, three will be presented as full papers and four as short papers. These papers and posters cover a number of themes, including: approaches to teaching databases, e.g. group centered and problem based learning; use of novel case studies, e.g. forensics and XML data; techniques and approaches for improving teaching and student learning processes; assessment techniques, e.g. peer review; methods for improving students abilities to develop database queries and develop E-R diagrams; and e-learning platforms for supporting teaching and learning
Construction safety and digital design: a review
As digital technologies become widely used in designing buildings and infrastructure, questions arise about
their impacts on construction safety. This review explores relationships between construction safety and
digital design practices with the aim of fostering and directing further research. It surveys state-of-the-art
research on databases, virtual reality, geographic information systems, 4D CAD, building information
modeling and sensing technologies, finding various digital tools for addressing safety issues in the
construction phase, but few tools to support design for construction safety. It also considers a literature on
safety critical, digital and design practices that raises a general concern about ‘mindlessness’ in the use of
technologies, and has implications for the emerging research agenda around construction safety and digital
design. Bringing these strands of literature together suggests new kinds of interventions, such as the
development of tools and processes for using digital models to promote mindfulness through multi-party
collaboration on safet
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