openHSU – Research Showcase

4506
Research outputs
779
People
140
Organizational Units
109
Projects
31
Conferences
17
Journals
Recent Additions
  • Publication
    Metadata only
    Towards an open-source semantic data infrastructure for integrating clinical and scientific data in cognition-guided surgery
    (SPIE, 2016-03-25)
    Fetzer, Andreas
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    Metzger, Jasmin
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    Katic, Darko
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    März, Keno
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    Wagner, Martin
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    Philipp, Patrick
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    Engelhardt, Sandy
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    Weller, Tobias
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    Zelzer, Sascha
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    Franz, Alfred M.
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    Schoch, Nicolai
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    Heuveline, Vincent
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    Rettinger, Achim
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    Speidel, Stefanie
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    Wolf, Ivo
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    Kenngott, Hannes
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    Mehrabi, Arianeb
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    Müller-Stich, Beat P.
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    Maier-Hein, Lena
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    Meinzer, Hans-Peter
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    Nolden, Marco
    In the surgical domain, individual clinical experience, which is derived in large part from past clinical cases, plays an important role in the treatment decision process. Simultaneously the surgeon has to keep track of a large amount of clinical data, emerging from a number of heterogeneous systems during all phases of surgical treatment. This is complemented with the constantly growing knowledge derived from clinical studies and literature. To recall this vast amount of information at the right moment poses a growing challenge that should be supported by adequate technology. While many tools and projects aim at sharing or integrating data from various sources or even provide knowledge-based decision support - to our knowledge - no concept has been proposed that addresses the entire surgical pathway by accessing the entire information in order to provide context-aware cognitive assistance. Therefore a semantic representation and central storage of data and knowledge is a fundamental requirement. We present a semantic data infrastructure for integrating heterogeneous surgical data sources based on a common knowledge representation. A combination of the Extensible Neuroimaging Archive Toolkit (XNAT) with semantic web technologies, standardized interfaces and a common application platform enables applications to access and semantically annotate data, perform semantic reasoning and eventually create individual context-aware surgical assistance. The infrastructure meets the requirements of a cognitive surgical assistant system and has been successfully applied in various use cases. The system is based completely on free technologies and is available to the community as an open-source package. © 2016 SPIE.
  • Publication
    Metadata only
    Survey of Semantic Description of REST APIs
    (Springer Science + Business Media, 2013-01-01)
    Verborgh, Ruben
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    Harth, Andreas
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    Stadtmüller, Steffen
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    Steiner, Thomas
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    Taheriyan, Mohsen
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    Van de Walle, Rik
    The REST architectural style assumes that client and server form a contract with content negotiation, not only on the data format but implicitly also on the semantics of the communicated data, i.e., an agreement on how the data have to be interpreted [247]. In different application scenarios such an agreement requires vendor-specific content types for the individual services to convey the meaning of the communicated data. The idea behind vendor-specific content types is that service providers can reuse content types and service consumers can make use of specific processors for the individual content types. In practice however, we see that many RESTful APIs on the Web simply make use of standard non-specific content types, e.g., text/xml or application/json [150]. Since the agreement on the semantics is only implicit, programmers developing client applications have to manually gain a deep understanding of several APIs from multiple providers. © Springer Science+Business Media New York 2014. All rights are reserved.
  • Publication
    Metadata only
    Automating the Use of Web APIs through Lightweight Semantics
    (Springer, 2012) ;
    Pedrinaci, Carlos
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    Liu, Dong
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    Alvaro, Guillermo
    Web services have already achieved a solid level of acceptance and play a major role for the rapid development of loosely-coupled component-based systems, overcoming heterogeneity within and between enterprises. Current developments in the world of services on the Web are marked by the proliferation of Web APIs and Web applications, commonly referred to as RESTful services, which show high potential and growing user acceptance. Still, despite the achieved progress, the wider adoption of Web APIs is hindered by the fact that their implementation and publication hardly follow any standard guidelines or formats. REST principles are indeed a good step in this direction but the vast majority of the APIs do not strictly adhere to these principles. As a consequence, in order to use them, developers are obliged to manually locate, retrieve, read and interpret heterogeneous documentation, and subsequently develop custom tailored software, which has a very low level of reusability. In summary, most tasks during the life-cycle of services require extensive manual effort and applications based on existing Web APIs suffer from a lack of automation. This tutorial introduces an approach and a set of integrated methods and tools to address this drawback, making services more accessible to both experts and non-expert users, by increasing the level of automation provided during common service tasks, such as the discovery of Web APIs, their composition and their invocation. The tutorial covers i) the conceptual underpinnings, which integrate Web APIs with state of the art technologies from the Web of Data and Semantic Web Services; ii) the presentation of an integrated suite of Web-based tools supporting service users; iii) and hands-on examples illustrating how the tools and technologies can help users in finding and exploiting existing Web APIs. © 2012 Springer-Verlag.
  • Publication
    Metadata only
    Adaptive Service Binding with Lightweight Semantic Web Services
    (Spinger, 2011)
    Pedrinaci, Carlos
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    Lambert, Dave
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    Liu, Dong
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    Domingue, John
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    Krummenacher, Reto
    Adaptive service selection is acknowledged to provide a certain number of advantages to optimise the service provisioning process or to cater for advanced service brokering. Semantic Web Services, that is services that have been enriched with semantic annotations have often been used for providing adaptive service selection by deferring the binding of services until runtime. Thus far, however, research on Semantic Web Services has mainly been dominated by rich conceptual frameworks such as WSMO and OWL-S which require a significant effort towards the annotation of services and rely on complex reasoning for which there are no efficient solutions that can scale to the Web yet. In this chapter, inline with current trends on the Semantic Web that sacrifice expressivity in favour of performance, we present a novel approach to providing adaptive service selection that relies on simple conceptual models for services and less expressive formalisms for which there currently exist mature and performant implementations. In particular, we present a set of conceptual models defined in RDF(S) that support both Web services and Web APIs and we show how simple templates abstracting user requirements can be automatically transformed into SPARQL to enable service selection in a scalable manner. © 2011 Springer-Verlag/Wien.
  • Publication
    Metadata only
    Lightweight semantics for automating the invocation of Web APIs
    (IEEE, 2011) ;
    Pedrinaci, Carlos
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    Li, Ning
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    Kopecky, Jacek
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    Domingue, John
    The past few years have been marked by the rapid increase in popularity and use of Web APIs as indicated by the growing number of available APIs and the multitude of applications built on top of them. The development and evolution of applications based on Web APIs is, however, hampered by the lack of automation achievable with current technologies. In this paper, we focus in particular on invocation, which as of now requires manual implementation of custom-tailored clients for each individual API. We present an approach for employing lightweight semantics for supporting the automated invocation of Web APIs. We investigate current Web API description forms and conduct an analysis of the requirements for a description model capable of supporting unified API invocation. In the light of these results, we propose a shared API description model that overcomes the current heterogeneity of the documentation and provides common grounds for enhancing APIs with semantic annotations that facilitate a general automated invocation solution. We evaluate the applicability of our approach by determining the coverage provided by our description model and via a prototypical implementation of an invocation engine. © 2011 IEEE.
  • Publication
    Metadata only
    Cross-lingual Web API classification and annotation
    (RWTH, 2011-11-03) ;
    Zilka, Lukas
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    Knoth, Petr
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    Pedrinaci, Carlos
    Recent developments on the Web are marked by the growing support for the Linked Data initiative, which encourages government and public organisations, as well as private institutions, to expose their data on the Web. This results in a plentitude of multi-lingual document collections where the original resources are published in the language, in which they are available. The challenges of multilingualism present on the Semantic Web are also reflected in the context of services on the Web, characterised by the rapid increase in popularity and use of Web APIs, as indicated by the growing number of available APIs and the applications built on top of them. Web APIs are commonly described in plain-text as part of Web pages, following no particular guidelines and conforming to no standards, despite some initial approaches in the area [1, 2]. Therefore, API providers publish descriptions in any language they see fit, making the service discovery and the subsequent processing of the documentation challenging tasks. In this paper, we present a cross-lingual approach that calculates semantic similarity of text to help classify and annotate Web APIs, based on their textual descriptions. Furthermore, we show how our solution can be implemented as part of SWEET [3], which is a tool that enables the semi-automated creation of semantic Web API descriptions. In addition, we demonstrate how the cross-lingual approach can be adopted to support the language-independent discovery of Web APIs.
  • Publication
    Metadata only
    Semantic annotation of web APIs with SWEET
    (RWTH, 2011-02-08) ;
    Pedrinaci, Carlos
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    Domingue, John
    Recently technology developments in the area of services on the Web are marked by the proliferation of Web applications and APIs. The development and evolution of applications based on Web APIs is, however, hampered by the lack of automation that can be achieved with current technologies. In this paper we present SWEET- Semantic Web sErvices Editing Tool- A lightweight Web application for creating seman- tic descriptions of Web APIs. SWEET directly supports the creation of mashups by enabling the semantic annotation of Web APIs, thus contributing to the automation of the discovery, composition and invocation service tasks. Furthermore, it enables the development of composite SWS based applications on top of Linked Data.
  • Publication
    Metadata only
    IServe: a linked services publishing platform
    (2010-06-11)
    Pedrinaci, Carlos
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    Liu, Dong
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    Lambert, David
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    Kopecky, Jacek
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    Domingue, John
    Despite the potential of service-orientation and the efforts devoted so far, we are still to witness a significant uptake of service technologies outside of enterprise environments. A core reason for this limited uptake is the lack of appropriate publishing platforms able to deal with the existing heterogeneity in the service technologies landscape and able to provide expressive yet simple and efficient discovery mechanisms. In this paper we describe iServe, a novel and open platform for publishing services which aims to better support their discovery and use. It exposes service descriptions as linked data expressed in terms of a simple vocabulary for describing services of different kinds with annotations in diverse formalisms. In addition to describing iServe, this paper also highlights the set of principles behind iServe, which we believe are essential for other generic repositories of semantic information notably ontology repositories.
  • Publication
    Metadata only
    Investigating Web APIs on the World Wide Web
    (IEEE, 2010-12) ;
    Pedrinaci, Carlos
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    Domingue, John
    The world of services on the Web, thus far limited to "classical" Web services based on WSDL and SOAP, has been increasingly marked by the domination of Web APIs, characterised by their relative simplicity and their natural suitability for the Web. Currently, the development of Web APIs is rather autonomous, guided by no established standards or rules, and Web API documentation is commonly not based on an interface description language such as WSDL, but is rather given directly in HTML as part of a webpage. As a result, the use of Web APIs requires extensive manual effort and the wealth of existing work on supporting common service tasks, including discovery, composition and invocation, can hardly be reused or adapted to APIs. Before we can achieve a higher level of automation and can make any significant improvement to current practices and technologies, we need to reach a deeper understanding of these. Therefore, in this paper we present a thorough analysis of the current landscape of Web API forms and descriptions, which has up-to-date remained unexplored. We base our findings on manually examining a body of publicly available APIs and, as a result, provide conclusions about common description forms, output types, usage of API parameters, invocation support, level of reusability, API granularity and authentication details. The collected data provides a solid basis for identifying deficiencies and realising how we can overcome existing limitations. More importantly, our analysis can be used as a basis for devising common standards and guidelines for Web API development. © 2010 IEEE.
  • Publication
    Metadata only
    Acquisition and management of Semantic Web service descriptions
    (RWTH, 2008-06-16)
    The increasing importance and use of Web services have resulted in a number of efforts targeted at automating Web service discovery and composition based on semantic descriptions of their properties. However, the progress in the automation of Web service discovery is still held back by the fact that the description of Web services in terms of semantic metadata is still mainly manually. This Ph.D. thesis addresses this problem by developing an approach for the acquisition and management of semantic Web service descriptions in order to facilitate efficient service discovery and composition. Specifically, this involves the collection of information about a Web service, the acquisition of semantic descriptions based on the collected information, and the structured storage of the generated semantic descriptions.