Resource Description Framework

The Resource Description Framework (RDF) is a World Wide Web Consortium (W3C) standard originally designed as a data model for metadata. It has come to be used as a general method for description and exchange of graph data. RDF provides a variety of syntax notations and data serialization formats, with Turtle (Terse RDF Triple Language) currently being the most widely used notation. RDF is a directed graph composed of triple statements. An RDF graph statement is represented by: 1) a node for the subject, 2) an arc that goes from a subject to an object for the predicate, and 3) a node for the object. Each of the three parts of the statement can be identified by a URI. An object can also be a literal value. This simple, flexible data model has a lot of expressive power to represent complex situations, relationships, and other things of interest, while also being appropriately abstract. RDF was adopted as a W3C recommendation in 1999. The RDF 1.0 specification was published in 2004, th

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This course introduces the key concepts and algorithms from the areas of information retrieval, data mining and knowledge bases, which constitute the foundations of today's Web-based distributed information systems.

This course gives an introduction to the fundamental concepts and methods of the Digital Humanities, both from a theoretical and applied point of view. The course introduces the Digital Humanities circle of processing and interpretation, from data acquisition to new understandings.

This course consists of two parts:

architecture of automation systems, hands-on lab
handling of faults and failures in real-time systems, including fault-tolerant computing

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UniStore: Querying a DHT-based Universal Storage

Manfred Hauswirth, Renault John Lecoultre, Jessica Müller, Roman Schmidt

The idea of collecting and combining large public data sets and services became more and more popular. The special characteristics of such systems and the requirements of the participants demand for strictly decentralized solutions. However, this comes along with several ambitious challenges a corresponding system has to overcome. In this demonstration paper, we present a lightweight distributed universal storage capable of dealing with those challenges, and providing a powerful and flexible way of building Internet-scale public data management systems. We introduce our approach based on a triple storage on top of a distributed hash table (DHT) overlay system, based on the ideas of a universal relation model and the resource description framework (RDF), and outline solved challenges as well as open issues.

2007

Closed-Loop Lifecycle Management of Service and Product in the Internet of Things: Semantic Framework for Knowledge Integration

Min-Jung Yoo

This paper describes our conceptual framework of closed-loop lifecycle information sharing for product-service in the Internet of Things (IoT). The framework is based on the ontology model of product-service and a type of IoT message standard, Open Messaging Interface (O-MI) and Open Data Format (O-DF), which ensures data communication. (1) Background: Based on an existing product lifecycle management (PLM) methodology, we enhanced the ontology model for the purpose of integrating efficiently the product-service ontology model that was newly developed; (2) Methods: The IoT message transfer layer is vertically integrated into a semantic knowledge framework inside which a Semantic Info-Node Agent (SINA) uses the message format as a common protocol of product-service lifecycle data transfer; (3) Results: The product-service ontology model facilitates information retrieval and knowledge extraction during the product lifecycle, while making more information available for the sake of service business creation. The vertical integration of IoT message transfer, encompassing all semantic layers, helps achieve a more flexible and modular approach to knowledge sharing in an IoT environment; (4) Contribution: A semantic data annotation applied to IoT can contribute to enhancing collected data types, which entails a richer knowledge extraction. The ontology-based PLM model enables as well the horizontal integration of heterogeneous PLM data while breaking traditional vertical information silos; (5) Conclusion: The framework was applied to a fictive case study with an electric car service for the purpose of demonstration. For the purpose of demonstrating the feasibility of the approach, the semantic model is implemented in Sesame APIs, which play the role of an Internet-connected Resource Description Framework (RDF) database.

Mdpi Ag2016

Path Processing using Solid State Storage

Manoussos Gavriil Athanassoulis

Recent advances in solid state technology have led to the introduction of Solid State Drives (SSDs). Todays SSDs store data persistently using NAND ﬂash memory. While SSDs are more expensive than hard disks when measured in dollars per gigabyte, they are signiﬁcantly cheaper when measured in dollars per random I/O per second. Additional storage technologies are under development, Phase Change Memory (PCM) being the next one to enter the marketplace. PCM is nonvolatile, it can be byte-addressable, and in future Multi Level Cell (MLC) devices, PCM is expected to be denser than DRAM. PCM has lower read and write latency compared to NAND ﬂash memory, and it can endure orders of magnitude more write cycles before wearing out. Recent research has shown that solid state devices can be particularly beneﬁcial for latency-bound applications involving dependent reads. Latency-bound applications like path processing in the context of graph processing or Resource Description Framework (RDF) data processing are typical examples of these applications. We demonstrate via a custom graph benchmark that even an early prototype Phase Change Memory device can offer signiﬁcant improvements over mature ﬂash devices (1.5x - 2.5x speedup in response times). We take this observation further by building Pythia, a prototype RDF repository tailor-made for Solid State Storage to investigate the predicted beneﬁts for these type of workloads that can be achieved in a properly designed RDF repository. We compare the performance of our repository against the state of the art RDF-3X repository in a limited set of tests and discuss the results. We ﬁnally compare the performance of our repository running on a PCM-based device against a state of the art ﬂash device, showing that there is indeed signiﬁcant gain to be achieved by using PCM for RDF processing.

2012

Semantic Web

The Semantic Web, sometimes known as Web 3.0 (not to be confused with Web3), is an extension of the World Wide Web through standards set by the World Wide Web Consortium (W3C). The goal of the Seman

Ontology (information science)

In information science, an ontology encompasses a representation, formal naming, and definition of the categories, properties, and relations between the concepts, data, and entities that substantiate

Web Ontology Language

The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. Ontologies are a formal way to describe taxonomies and classification networks, essentially

This course consists of two parts:

architecture of automation systems, hands-on lab
handling of faults and failures in real-time systems, including fault-tolerant computing