426 research outputs found
The SSN ontology of the W3C semantic sensor network incubator group
The W3C Semantic Sensor Network Incubator group (the SSN-XG) produced an OWL 2 ontology to describe sensors and observations ? the SSN ontology, available at http://purl.oclc.org/NET/ssnx/ssn. The SSN ontology can describe sensors in terms of capabilities, measurement processes, observations and deployments. This article describes the SSN ontology. It further gives an example and describes the use of the ontology in recent research projects
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
A study of existing Ontologies in the IoT-domain
Several domains have adopted the increasing use of IoT-based devices to
collect sensor data for generating abstractions and perceptions of the real
world. This sensor data is multi-modal and heterogeneous in nature. This
heterogeneity induces interoperability issues while developing cross-domain
applications, thereby restricting the possibility of reusing sensor data to
develop new applications. As a solution to this, semantic approaches have been
proposed in the literature to tackle problems related to interoperability of
sensor data. Several ontologies have been proposed to handle different aspects
of IoT-based sensor data collection, ranging from discovering the IoT sensors
for data collection to applying reasoning on the collected sensor data for
drawing inferences. In this paper, we survey these existing semantic ontologies
to provide an overview of the recent developments in this field. We highlight
the fundamental ontological concepts (e.g., sensor-capabilities and
context-awareness) required for an IoT-based application, and survey the
existing ontologies which include these concepts. Based on our study, we also
identify the shortcomings of currently available ontologies, which serves as a
stepping stone to state the need for a common unified ontology for the IoT
domain.Comment: Submitted to Elsevier JWS SI on Web semantics for the Internet/Web of
Thing
Semantic Gateway as a Service architecture for IoT Interoperability
The Internet of Things (IoT) is set to occupy a substantial component of
future Internet. The IoT connects sensors and devices that record physical
observations to applications and services of the Internet. As a successor to
technologies such as RFID and Wireless Sensor Networks (WSN), the IoT has
stumbled into vertical silos of proprietary systems, providing little or no
interoperability with similar systems. As the IoT represents future state of
the Internet, an intelligent and scalable architecture is required to provide
connectivity between these silos, enabling discovery of physical sensors and
interpretation of messages between things. This paper proposes a gateway and
Semantic Web enabled IoT architecture to provide interoperability between
systems using established communication and data standards. The Semantic
Gateway as Service (SGS) allows translation between messaging protocols such as
XMPP, CoAP and MQTT via a multi-protocol proxy architecture. Utilization of
broadly accepted specifications such as W3C's Semantic Sensor Network (SSN)
ontology for semantic annotations of sensor data provide semantic
interoperability between messages and support semantic reasoning to obtain
higher-level actionable knowledge from low-level sensor data.Comment: 16 page
Towards IoT platforms’ integration:Semantic Translations between W3C SSN and ETSI SAREF
Several IoT ontologies have been developed lately to improve the semantic interoperability of IoT solutions. The most popular of these ontologies, the W3C Semantic Sensor Network (SSN), is considered an ontological foundation for diverse IoT initiatives, particularly OpenIoT. With characteristics similar to SSN, the ETSI Smart Appliances REFerence (SAREF) ontology evolved from the needs of smart home solutions to common requirements of IoT. Some IoT solutions rely on platform-specific ontologies and their integration requires mechanisms to align these ontologies. In this paper we discuss the ontology alignment between SSN and SAREF, identifying mapping alternatives and proposing basic mappings that can be re-used to define more complex ones. We introduce here an initial specification of the semantic translations from the main elements of SSN to SAREF, which includes classes, object properties and data properties. The alignment will be used in a semantic matching process leveraging the semantic mediator component of the INTER-IoT project. An initial evaluation of the translation was executed by translating the wind sensor (Vaisala WM30), an example provided by the W3C, from SSN to SAREF. This initial evaluation demonstrates the coherence and feasibility of the proposed mappings
Transforming meteorological data into linked data
This paper describes the process followed in order to make some of the public meterological data from the Agencia Estatal de Meteorología (AEMET, Spanish Meteorological Office) available as Linked Data. The method followed has been already used to publish geographical, statistical, and leisure data. The data selected for publication are generated every ten minutes by the 250 automatic stations that belong to AEMET and that are deployed across Spain. These data are available as spreadsheets in the AEMET data catalog, and contain more than twenty types of measurements per station. Spreadsheets are retrieved from the website, processed with Python scripts, transformed to RDF according to an ontology network about meteorology that reuses the W3C SSN Ontology, published in a triple store and visualized in maps with Map4rdf
An Efficient Bit Vector Approach to Semantics-Based Machine Perception in Resource-Constrained Devices
The primary challenge of machine perception is to define efficient computational methods to derive high-level knowledge from low-level sensor observation data. Emerging solutions are using ontologies for expressive representation of concepts in the domain of sensing and perception, which enable advanced integration and interpretation of heterogeneous sensor data. The computational complexity of OWL, however, seriously limits its applicability and use within resource-constrained environments, such as mobile devices. To overcome this issue, we employ OWL to formally define the inference tasks needed for machine perception – explanation and discrimination – and then provide efficient algorithms for these tasks, using bit-vector encodings and operations. The applicability of our approach to machine perception is evaluated on a smart-phone mobile device, demonstrating dramatic improvements in both efficiency and scale
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