We describe a prototype knowledge base that uses semantic web technologies to provide a service for querying a large and expanding collection of public data about resilience, dependability and security. We report progress and identify opportunities to support resilience-explicit computing by developing metadata-based descriptions of resilience mechanisms that can be used to support design time and, potentially, run-time decision making

Anderson, Tom

Andrews, Zoe

Fitzgerald, John

Glaser, Hugh

Millard, Ian

Randell, Brian

English

Southampton (e-Prints Soton)

The ReSIST Resilience Knowledge BaseT. Anderson, Z.H. Andrews,J.S. Fitzgerald, B. RandellSchool of Computing ScienceNewcastle UniversityNewcastle upon Tyne, NE1 7RU, UK{Tom.Anderson, Z.H.Andrews, John.Fitzgerald,Brian.Randell@ncl.ac.uk}@ncl.ac.ukH. Glaser, I.C. MillardSchool of Electronics and Computer ScienceUniversity of SouthamptonSouthampton, SO17 1BJ, UK{hg, icm}@ecs.soton.ac.ukAbstractWe describe a prototype knowledge base that uses se-mantic web technologies to provide a service for queryinga large and expanding collection of public data about re-silience, dependability and security. We report progress andidentify opportunities to support resilience-explicit comput-ing by developing metadata-based descriptions of resiliencemechanisms that can be used to support design time and,potentially, run-time decision making.1. IntroductionKnowledge is the greatest asset that the scientiﬁc andengineering community has in facing the challenges of de-veloping resilient systems, particularly those that are dis-tributed, large-scale, heterogeneous and evolving dynami-cally. Our goal is to develop resources that help the commu-nity gain the most value from its knowledge assets. Seman-tic web technologies offer many beneﬁts over and above theresults of applying conventional web-based search engines,enabling rich annotation and the synthesis of data from dis-parate sources. For example, through the application ofontological mapping, researchers may access informationwhich is relevant to their query terms, but which has orig-inated from sources or been described in vocabularies withwhich they are not familiar.The EU Network of Excellence on Resilience for Sur-vivability in IST (ReSIST) aims to promote integration ofresearchers so that fundamental topics on resilient systemsare addressed by a critical mass of co-operative work. Keyto this is the provision of a comprehensive and accessibleknowledge base to support this effort beyond the life ofthe network as a formal project. A prototype of such a re-silience knowledge base (RKB) has been developed. Wehere provide an overview of the technologies employed,current status and the potential for exploitation of the RKBin supporting resilience-explicit approaches to system de-velopment and operation.2. Resilience Knowledge BaseThe ReSIST RKB is a collection of facts recorded assemantic RDF statements, describing real resources suchas people, projects, publications, courses, and the relation-shipsbetweenthem. Itisimplementedusing3store, anopensource repository designed speciﬁcally to handle high vol-umes of RDF, and is an evolution of the ‘CS AKTive Space’system that won the 2003 Semantic Web Challenge [4].2.1. Content and InterfacesThe RKB offers a number of interfaces to facilitate dataacquisition, querying and visualisation, for both humanusers and service oriented software processes. These in-clude custom web-based interfaces integrated within a Se-mantic Wiki, enabling users to record their academic re-search interests and to upload data regarding training mate-rials in an ontologically mediated fashion.Data on people, publications and projects is provided byReSIST participants, in addition to external database andweb resources. Over 50 million RDF triples have been col-lected (as of early 2007) including all public data held byCORDIS, NSF (EU & US research projects), DBLP, Cite-seer and the ACM (publications) and from the RISKS fo-rum. Characteristic data on the corpus of papers publishedat DSN conferences and the (Oakland) symposia on Secu-rity & Privacy have recently been added. Resolving co-references and name variants between different data sources(e.g. H. Glaser vs. Hugh Glaser) is an acute problem withpublications and people, hence we are developing an auto-matic resolution scheme within the RKB.A prototype interface has been developed to allow usersto navigate and explore this large information repository.The RKB Explorer shows derived connections between re-lated resources. The ﬁgure below is a snapshot from a ‘Peo-ple’ view, indicating the strengths of Ian Millard’s connec-tions to other people by the weight of the connecting lines.These strengths are calculated dynamically by the RKB,taking into account factors such as co-authorship of papersand co-membership of projects. There are also similar RKBviews for papers, projects and research topics.2.2. Resilience OntologyPre-existing ontologies have been used for general con-cepts such as projects and publications; an ontology forcourseware was created. However, the primary ontologydeveloped speciﬁcally for the RKB is on Dependabilityand Security (D&S) and is derived from the taxonomies ofAvizienis et al. [1]. This is represented in OWL and in-corporates 166 terms related to Dependability and Security,and 23 to Systems.Much of the RKB content is derived from published arti-cles, for which keywords are either absent, arbitrary or fromexisting (and unsuitable) classiﬁcation schemes. Existingschemes are being mapped into the emerging D&S ontol-ogy. For publications without conformant tagging, an inter-face has been developed to allow domain experts to classifypapers manually against the D&S ontology. A current taskis to exploit linguistic based term-extraction tools (devel-oped at Saarbrucken) to automate the classiﬁcation of pa-pers, using the manually classiﬁed papers as a training set.3. Support for Resilience-Explicit ComputingResilience-Explicit (Res-Ex) Computing refers to the ex-plicit use of information (metadata) on the resilience char-acteristics of system components, infrastructure and envi-ronment to guide decision-making at either design time orin the running system [2, 3]. Support for such decision mak-ing requires access to resilience mechanisms (design pat-terns, tools, processes) described in terms of their antici-pated effects on system resilience. The RKB has a natu-ral role to play here. Machine-interpretation and manipula-tion of metadata would require that the semantics of variousresilience-related concepts be deﬁned within an ontology,to enable a search for information relevant to design (suchas research or application reports) and even information tosupport run-time reconﬁguration. For example, a search fora conﬁguration to provide a speciﬁed level of service avail-ability (described in terms of metadata) might form part ofan off-line or on-line evolution step.An aim for our current work is to support the descriptionof a wide range of example resilience mechanisms withinthe RKB, conformant to the relevant ontologies. Compe-tency questions that we expect the Res-Ex enhanced RKBto address for the beneﬁt of researchers have been identiﬁedfrom the point of view of researchers wishing to developpolicies and architectures for run-time resilience. We aredeveloping an outline ontology and data acquisition pagein the Semantic Wiki to support the addition of resiliencemechanism descriptions that explicitly identify metadata.Ten candidate speciﬁc resilience mechanisms have beenproposed by ReSIST partners, ranging from classical designpatterns such as recovery blocks to validation tools such asmodel checkers and human factors techniques such as dy-namic function allocation. We are thus developing new ma-terial to add value to the emerging RKB.4. Conclusions and Future WorkThe protoype RKB Explorer interface is accessible foruse at http://resist.ecs.soton.ac.uk/explorer/From a resilience-explicit perspective, we hope that pro-ponents of new resilience mechanisms will see beneﬁts incontributing standardised descriptions of them to the RKB,as an aid to research as well as a way of promoting their use.Acknowledgements: We are grateful to our ReSIST(www.resist-noe.org) partners for their contributions, and tothe EU for ﬁnancial support under contract 026764.References[1] A. Avizienis, J.-C. Laprie, B. Randell, and C. Landwehr. Ba-sic concepts and taxonomy of dependable and secure com-puting. IEEE Trans. on Dependable and Secure Computing,1(1):11–33, 2004.[2] J. S. Fitzgerald, S. Parastatidis, A. Romanovsky, and P. Wat-son. Dependability-explicit computing in service-oriented ar-chitectures. In Proc. Int. Conf. on Dependable Systems andNetworks (Supp. Vol.), pages 34–35, 2004.[3] M. Kaniche, J.-C. Laprie, and J. P. Blanquart. A frame-workfor dependability engineering of critical computing systems.Safety Science, 40(9):731–752, 2002.[4] N. Shadbolt, N. Gibbins, H. Glaser, S. Harris, and m.c.schraefel. CS AKTive Space, or how we learned to stop wor-rying and love the semantic web. IEEE Intelligent Systems,19(3):41–47, 2004.

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