2,952 research outputs found
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
Estimating Fire Weather Indices via Semantic Reasoning over Wireless Sensor Network Data Streams
Wildfires are frequent, devastating events in Australia that regularly cause
significant loss of life and widespread property damage. Fire weather indices
are a widely-adopted method for measuring fire danger and they play a
significant role in issuing bushfire warnings and in anticipating demand for
bushfire management resources. Existing systems that calculate fire weather
indices are limited due to low spatial and temporal resolution. Localized
wireless sensor networks, on the other hand, gather continuous sensor data
measuring variables such as air temperature, relative humidity, rainfall and
wind speed at high resolutions. However, using wireless sensor networks to
estimate fire weather indices is a challenge due to data quality issues, lack
of standard data formats and lack of agreement on thresholds and methods for
calculating fire weather indices. Within the scope of this paper, we propose a
standardized approach to calculating Fire Weather Indices (a.k.a. fire danger
ratings) and overcome a number of the challenges by applying Semantic Web
Technologies to the processing of data streams from a wireless sensor network
deployed in the Springbrook region of South East Queensland. This paper
describes the underlying ontologies, the semantic reasoning and the Semantic
Fire Weather Index (SFWI) system that we have developed to enable domain
experts to specify and adapt rules for calculating Fire Weather Indices. We
also describe the Web-based mapping interface that we have developed, that
enables users to improve their understanding of how fire weather indices vary
over time within a particular region.Finally, we discuss our evaluation results
that indicate that the proposed system outperforms state-of-the-art techniques
in terms of accuracy, precision and query performance.Comment: 20pages, 12 figure
An ontology-based approach to Automatic Generation of GUI for Data Entry
This thesis reports an ontology-based approach to automatic generation of highly tailored GUI components that can make customized data requests for the end users. Using this GUI generator, without knowing any programming skill a domain expert can browse the data schema through the ontology file of his/her own field, choose attribute fields according to business\u27s needs, and make a highly customized GUI for end users\u27 data requests input. The interface for the domain expert is a tree view structure that shows not only the domain taxonomy categories but also the relationships between classes. By clicking the checkbox associated with each class, the expert indicates his/her choice of the needed information. These choices are stored in a metadata document in XML. From the viewpoint of programmers, the metadata contains no ambiguity; every class in an ontology is unique. The utilizations of the metadata can be various; I have carried out the process of GUI generation. Since every class and every attribute in the class has been formally specified in the ontology, generating GUI is automatic. This approach has been applied to a use case scenario in meteorological and oceanographic (METOC) area. The resulting features of this prototype have been reported in this thesis
Aerial Networking for the Implementation of Cooperative Control on Small Unmanned Aerial Systems
The employment of Small Unmanned Aerial Systems (SUAS) for reconnaissance and surveillance missions is a vital capability of the United States military. Cooperative control algorithms for SUAS can enable tactical multi-vehicle configurations for communications extension, intelligent navigation, and a multitude of other applications. Past research at AFIT has designed and simulated a cooperative rover-relay algorithm for extended communications and has investigated its implementation through various modem configurations. This research explores aerial networking options for implementing cooperative control and applies them to an actual SUAS. Using Commercial Off-The-Shelf (COTS) hardware, a system was designed and flight tested to implement the rover-relay algorithm and provide a testbed system for future research in cooperative control. Two different modem configurations were designed and tested. The first modem configuration was demonstrated through a series of ground and flight tests to successfully relay autopilot commands and telemetry between a ground station and a rover aircraft through a relay aircraft. This configuration effectively doubles the effective range of the rover system to 1.2 miles, together with an algorithm that autonomously navigates the relay aircraft to an optimal location. Secondly, a mesh network was configured and tested. This configuration successfully relayed aircraft telemetry to the ground station from each vehicle in the network. However, the network suffered from low throughput, which limited autopilot functionality, such as updating navigation waypoints to each aircraft. The results suggest the system be updated with more capable modems in a mesh configuration to broaden the possibilities for future research in cooperative applications
vSPARQL: A View Definition Language for the Semantic Web
Translational medicine applications would like to leverage the biological and biomedical ontologies, vocabularies, and data sets available on the semantic web. We present a general solution for RDF information set reuse inspired by database views. Our view definition language, vSPARQL, allows applications to specify the exact content that they are interested in and how that content should be restructured or modified. Applications can access relevant content by querying against these view definitions. We evaluate the expressivity of our approach by defining views for practical use cases and comparing our view definition language to existing query languages
A process-based control for evolvable production systems
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresNowadays, companies in a challenging environment are compelled to adapt to the rapid changes in the manufacturing business. The search for new processes to create products with short life-cycles at low cost, while keeping the same levels of productivity and quality is greater than ever. This has generated the need to create even more agile manufacturing systems, which could easily adapt to the market changes at a low cost.
Advances in information technologies have allowed manufacturing systems to achieve
new levels of agility, opening the doors to new approaches. These same advances helped
companies in several sectors other than manufacturing to gain e ectiveness through the
synchronization of the processes of their several departments by using Business Process
Management tools.
This thesis proposes a system that reacts and adapts itself to di erent production
orders by means of recon guration. To reach this goal, the concept of Business Process
Management was used. This concept, already used in many companies, allows them to
model their inner behaviours with processes that can be changed according to their needs.
A manufacturing system using this may become equally agile and alter its functioning in
accordance with the needs of other departments of the same company.
To create the system presented in this thesis it was used a multi-agent architecture
based on process execution. Each agent contains a knowledge base, used by its processes,that stores internal or external information. This system may be used not only in the manufacturing shop oor, but also in any other areas within a company.
This thesis also presents an application of the system to the shop oor, based on the
Evolvable Production Systems concept, in which each agent represents a manufacturing
resource that o ers a given set of services useful to the production process. The resources,by means of the agents, may aggregate among themselves to execute services together.
Keywords: Manufacturing system, multi-agent system, ontology, process, BPM, EPS
A Goal-Directed and Policy-Based Approach to System Management
This thesis presents a domain-independent approach to dynamic system management using goals and policies. A goal is a general, high-level aim a system must continually work toward achieving. A policy is a statement of how a system should behave for a given set of detectable events and conditions. Combined, goals may be realised through the selection and execution of policies that contribute to their aims. In this manner, a system may be managed using a goal-directed, policy-based approach.
The approach is a collection of related techniques and tools: a policy language and policy system, goal definition and refinement via policy selection, and conflict filtering among policies. Central to these themes, ontologies are used to model application domains, and incorporate domain knowledge within the system. The ACCENT policy system (Advanced Component Control Enhancing Network Technologies, http://www.cs.stir.ac.uk/accent) is used as a base for the approach, while goals and policies are defined using an extension of APPEL (Adaptable and Programmable Policy Environment and Language, http://www.cs.stir.ac.uk/appel).
The approach differs from existing work in that it reduces system state, goals and policies to a numerical rather than logical form. This is more user-friendly as the goal domain may be expressed without any knowledge of formal methods. All developed techniques and tools are entirely domain-independent, allowing for reuse with other event-driven systems. The ability to express a system aim as a goal provides more powerful and proactive high-level management than was previously possible using policies alone. The approach is demonstrated and evaluated within this thesis for the domains of Internet telephony and sensor network/wind turbine management
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