Christoph Ludwig

TextGrid and eHumanities

TextGrid is a new Grid project in the framework of the German D-Grid initiative, with the aim to deploy Grid technologies for humanities scholars working on historical (German) texts. Its two roots, humanities computing and eScience (Grid computing used by research together with modern communication technologies), are the basis for TextGrid to provide pioneer work in eHumanities. After summarizing Humanities Computing and modern network technologies, community expectations in the fields of philological edition and other application areas are set forth, from which functional requirements such as modularity, distribution, etc. are distilled. The first version of the TextGrid architecture was designed in accordance with these requirements, and focuses on openness by standard conformance and encapsulation. It provides storage Grid services via a pure Web Services interface to dedicated Web Services tools for different aspects of text processing, analysis and retrieval. This platform aims to provide easily usable tools for scholars, but also specifies interfaces for external program developers to add functionality.

TextGrid as a Digital Ecosystem

The TextGrid project brings together eight German institutions from both academia and the commercial sector to create a community grid for the collaborative editing, annotation, analysis and publication of specialist texts. Leveraging the grid infrastructure, textual data and supporting images from various research projects and content providers such as archives and libraries can fuse into a virtual corpus that can be seamlessly searched and analyzed. TextGrid will be a key enabler for collaborative textual scholarship, aiming at overcoming current isolation in research and facilitating cooperative working methods and the sharing of resources, content and software agents alike. It will also enable quantitative and comparative studies across corpora on a scale that might otherwise have been impossible to achieve.

Digital ecosystems of eHumanities resources and services

Having concentrated in (Kuster et al., 2007) on the services that contribute to TextGrid, we now look in details at the second key aspect of eHumanities digital ecosystems, content, which in the case of TextGrid consists primarily of textual and image resources. We analyze the role of those resources as first-class citizens of this eHumanities ecosystem. Abstracting from the concrete use case of TextGrid, we look at grid-based digital ecosystems from the new paradigm of resource-oriented architectures (ROA) and elaborate on the implications that this paradigm shift will have for digital ecosystems.

TextGrid provenance tools for digital humanities ecosystems

Philological research is very much concerned with the idea of data provenance. However, existing provenance models in eResearch and eScience for data and workflow are ill-applicable to the specific challenges of philological research in the digital age. In philology, provenance data must be collected not only for the complete research objects, but also for fragments — in particular for texts. This necessitates a much richer provenance model that is interwoven with the objects textual structure and supports the association of provenance data with individual words. It must also permit multiple interpretations of provenance for a single research object. In this, the requirements in digital philology can also be paradigmatic for very fine-granular provenance information collection in other domain-specific digital ecosystems. This paper elaborates key requirements of data and workflow provenance in the philologies and demonstrates how the tools in the TextGrid digital humanities ecosystem answer to those needs. In addition to TextGrids text-image-link editor and its underlying data model the paper also introduces the humanities provenance tool HPT for RESTful workflows. HPT is specifically geared to supporting the provenance requirements for workflows in heterogeneous digital humanities ecosystems.

Open ehumanities digital ecosystems and the role of resource registries

The last few years have seen a massive push towards collaborative working methods in the humanities. Many large and small eHumanities Digital Ecosystems (DEs) have sprung into existence. The big challenge ahead is now to see how these subsystems can begin to merge into one larger eHumanities DE while still maintaining their individual characters and strengths. Starting out from a presentation of TextGrid as an exemplary DE in the eHumanities, the article studies two prerequisites for successful interoperability between DEs in the field, namely loosely-coupled services and the visibility of resources. The authors then propose a reference ontology for eHumanities resources, both services and documents alike.

Versioning in distributed semantic registries

Change is a constant (not only) in the Semantic Web. Both instance data and ontologies evolve. These changes are a piecemeal process, morphing from version to version both for conceptualizations / ontologies and for the related instance data / individuals. Individual versions capture valuable information about ontologies and instance data that were valid at a given point in time.n In this article we present a design for versioning instance data and outline its particular role in ontology evolution. We describe an implementation strategy for versioning instance data in the Semantic Web in the light of existing approaches working change logs and change definition languages. We show how this strategy is implemented our Topic Map based semantic database Isidorus and is used in pan-European eGovernment applications. We also show how the versioning strategy plays together with a new Atom-based European specification for change propagation of distributed metadata.

E2ESU — stable foundations for digital business ecosystems

Change is widely seen as one of the defining characteristics of digital ecosystems. We argue that stability and, in particular, stable foundations are equally important and are, in fact, a precondition for openness to change. At present, more and more ICT products become commodities in fact, the commoditization can be seen as one key drivers behind the radical and rapid changes in the Web-2.0 world. Future economic growth in the Internet requires collaborative and intelligent services and the opportunity for service providers to compose and integrate widely distributed services into adaptable end-to-end business processes. We describe the end-to-end service utility (E2ESU) initiative that aims to create a thin, well specified, linking infrastructure layer atop the current Internet infrastructure that serves as a sound and firm foundation for the value-added services developed by service providers. The utilities are so to say the ground layer in an ecosystem inhabited by utilities, value-added services, and service-based applications. However, our notion of utilities challenges the often published assertion that all agents in an ecosystem may mutate without any external restrictions. We contend instead that the basic building blocks of a reliable and dependable infrastructure backbone must vary, but within the limits of clear-cut and well-defined specifications.

Ontology in a Wiki collaboratively authoring ontologies the simple way

The development and maintenance of ontologies more often than not requires tools for their collaborative authoring. The existing tools come with a significant overhead for their installation and operation. This overhead is acceptable for large ontologies with hundreds and thousands of classes; but in some communities and projects e.g. in the eHumanites it poses a major adoption barrier. This paper makes the case that often a low-tech, Wiki-based approach to ontology authoring that prefers conventions over tool-enforced rules can be an appropriate solution. It outlines under which conditions such a simple solution is adequate and demonstrates the practicality of this approach such using a real-life use case from eGovernment standardization.

TextGrid: eScholarship und vernetzte AngeboteTextGrid: eScholarship in a Network of Resources

Zusammenfassung Das TextGrid-Konsortium bringt acht über ganz Deutschland verteilte Institutionen aus dem akademischen und kommerziellen Sektor zusammen, um eine modulare Plattform für verteilte und kooperative wissenschaftliche Textdatenverarbeitung zu erarbeiten. Unter Einsatz der Grid-Infrastruktur führt es verschiedene Datenstrukturen aus unterschiedlichen Projekten in einem virtuellen Korpus zusammen, das als Ganzes oder in ausgewählten Teilen analysiert und bearbeitet werden kann. Als dezidiert auf Kollaboration auch über die Grenzen von TextGrid selbst ausgerichtete Plattform verändert sie auch den Arbeitsalltag des geisteswissenschaftlichen Forschers, weg vom Bild des weitgehend isoliert arbeitenden Philologen hin zur Teamarbeit an Daten und Werkzeugen gleichermaßen. Aus Informatiksicht ist TextGrid wiederum ein Beispiel für ein komplexes, lose gekoppeltes Digitales Ökosystem mit Spielern aus vielen Disziplinen und Ländern.

Software Reuse through Resource Registries

Software engineering has always had software reuse as one of its key tenets. In both service-oriented and resource-oriented architectures visibility is a prerequisite for fulfilling their respective promises, namely easier reuse of services and resources. Resource registries are a way to achieve such visibility. We argue that resource registries must separate technical, semantic and organizational aspects and leverage popular existing standards. This way they are able to adapt to domain specific requirements and a multitude of categorizations of and associations between resources. These arguments are backed up by examples primarily from the nascent pan-European eGovernment resource network.