46,466 research outputs found
A theorem prover-based analysis tool for object-oriented databases
We present a theorem-prover based analysis tool for object-oriented database systems with integrity constraints. Object-oriented database specifications are mapped to higher-order logic (HOL). This allows us to reason about the semantics of database operations using a mechanical theorem prover such as Isabelle or PVS. The tool can be used to verify various semantics requirements of the schema (such as transaction safety, compensation, and commutativity) to support the advanced transaction models used in workflow and cooperative work. We give an example of method safety analysis for the generic structure editing operations of a cooperative authoring system
Making object-oriented databases more knowledgeable (From ADAM to ABEL)
Tesis leida en la Universidad de Aberdeen. 178 p.The salient points of this thesis are as follows:
• Object-Oriented Databases can help in solving the impedance mismatch problem
by introducing methods. However, methods have sometimes been overused in the
sense th at the code encapsulated refers not only to how the operation is implemented
but also to other kinds of knowledge that are implicit in the code. The
disadvantages of this approach for modelling integrity constraints, user-defined relationships
and active behaviour are pointed out.
• The ADAM Object-Oriented Database has been extended to allow the designer
to specify integrity constraints declaratively. A constraint equation approach is
implemented th at supports the inheritance of constraints.
• A need for semantic-rich user-defined relationships has been identified. In this thesis,
relationships are represented as objects. An approach to enhance the semantics
of relationships in both its structural and behavioural aspects is presented. The
most novel idea of the approach presented is the support of the inferred properties
and the operational semantics of relationships.
• Active Databases have recently become an im portant area of research. This thesis
shows how to extend an Object-Oriented Database with active capabilities. The
principal contribution lies in representing as ‘first-class’ objects not only the active
rules but also the rule manager itself. Hence, besides handling active rules as
any other object in the system, future requirements can be supported just by
specialising the current rule manager.
• Active rules have been proposed for several purposes. Several examples, are given
of the direct use of rules. However, higher level tools can be provided of which rule
Context Aware Computing for The Internet of Things: A Survey
As we are moving towards the Internet of Things (IoT), the number of sensors
deployed around the world is growing at a rapid pace. Market research has shown
a significant growth of sensor deployments over the past decade and has
predicted a significant increment of the growth rate in the future. These
sensors continuously generate enormous amounts of data. However, in order to
add value to raw sensor data we need to understand it. Collection, modelling,
reasoning, and distribution of context in relation to sensor data plays
critical role in this challenge. Context-aware computing has proven to be
successful in understanding sensor data. In this paper, we survey context
awareness from an IoT perspective. We present the necessary background by
introducing the IoT paradigm and context-aware fundamentals at the beginning.
Then we provide an in-depth analysis of context life cycle. We evaluate a
subset of projects (50) which represent the majority of research and commercial
solutions proposed in the field of context-aware computing conducted over the
last decade (2001-2011) based on our own taxonomy. Finally, based on our
evaluation, we highlight the lessons to be learnt from the past and some
possible directions for future research. The survey addresses a broad range of
techniques, methods, models, functionalities, systems, applications, and
middleware solutions related to context awareness and IoT. Our goal is not only
to analyse, compare and consolidate past research work but also to appreciate
their findings and discuss their applicability towards the IoT.Comment: IEEE Communications Surveys & Tutorials Journal, 201
Characterising aggregations with existence dependency.
Abstract: The concept of aggregation is considered as one of the basic principles in object-oriented analysis. There is however no standard definition of this concept and each object-oriented analysis method has its own definition of aggregation. The aim of this paper is not to discuss the different types of aggregation that exist. However, having assessed the complexity of the concept, we will illustrate how a basic set of formal concepts is sufficient to define of the structural and behavioral aspects of different existing flavours of aggregation. If a development method wants to offer a rich concept such as aggregation, it can define the semantics of the desired flavour of the aggregation using these core formal concepts. Analysts then have the choice to use the aggregation defined by the method or to fall back on the core concepts if a different flavour of aggregation is needed to model the situation at hand.Principles; Model;
A Context-Oriented Extension of F#
Context-Oriented programming languages provide us with primitive constructs
to adapt program behaviour depending on the evolution of their operational
environment, namely the context. In previous work we proposed ML_CoDa, a
context-oriented language with two-components: a declarative constituent for
programming the context and a functional one for computing. This paper
describes the implementation of ML_CoDa as an extension of F#.Comment: In Proceedings FOCLASA 2015, arXiv:1512.0694
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