Permanent Objects, Disposable Systems

4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-05-19 01:00 PM – 02:30 PMThe California Digital Library (CDL) preservation program is re-envisioning its curation infrastructure as a set of loosely-coupled, distributed micro-services. There are many monolithic systems that support a range of preservation activities but also require the user and the hosting institution to buy-in to a particular system culture. The result is an institution that becomes, say, a DSpace, Fedora, or LOCKSS "shop", with a specific worldview and set of object flows and structures that will eventually need to be abandoned when it comes time to transition to the next system. Experience shows that these transitions are unavoidable, despite claims that once an object is in the system, it will be safe forever. In view of this it is safer and more cost-effective to acknowledge from the outset the inevitable transient nature of systems and to plan on managing, rather than resisting change. The disruption caused by change can be mitigated by basing curation services on simple universal structures and protocols (e.g., filesystems, HTTP) and micro-services that operate on them. We promote a "mix and match" approach in which appropriate content- and context-specific curation workflows can be nimbly constructed by combining necessary functions drawn from a granular set of independent micro-services. Micro-services, whether deployed in isolation or in combination, are especially suited to exploitation upstream towards content creators who normally don't want to think about preservation, especially if it's costly; compared to buying into an entire curation culture, it is easy to adopt a small, inexpensive tool that requires very little commitment. We see digital curation as an ongoing process of enrichment at all stages in the lifecycle of a digital object. Because the early developmental stages are so critical to an object's health and longevity, it is desirable to push curation "best practices" as far upstream towards the object creators as possible. If preservation is considered only when objects are close to retirement, it is often too late to correct the structural and semantic deficiencies that can impair object usability. The later the intervention, the more expensive the correction process, and it is always difficult to fund interventions for "has been" objects. In contrast, early stage curation challenges traditional practices. Traditionally, preservation actions are often based on end-stage processing, where objects are deposited "as is" and kept out of harm's way by limiting access (i.e., dark archives). While some systems are designed to be dark or "dim", with limited access and little regard for versioning or object enrichment, enrichment and access are now seen as necessary curation actions, that is, interventions for the sake of preservation. In particular, the darkness of an entire collection can change in the blink of an eye, for example, as the result of a court ruling or access rights purchase; turning the lights on for a collection should be as simple as throwing a switch, and not require transferring the collection from a "preservation repository" to an "access repository". Effective curation services must be flexible and easily configurable in order to respond appropriately to the wide diversity of content and content uses. To be most effective, not only should curation practices be pushed upstream but also they should be pushed out to many different contexts. The micro-services approach promotes the idea that curation is an outcome, not a place. Curation actions should be applied to content where it most usefully exists for the convenience of its creators or users. For example, high value digital assets in access repositories, or even scholars' desktops, would certainly benefit from such things as persistent identification or regular audits to discover and repair bit-level damage, functions usually available only in the context of a "preservation system" but now easily applied to content where it most usefully resides without requiring transfer to a central location

Information geometry of asymptotically AdS black holes

We investigate thermodynamic geometries of two families of asymptotically Anti-de Sitter black holes, i.e. the Reissner-Nordstr\"om Anti-de Sitter in four dimensions and the BTZ black hole. It is found that the Anti-de Sitter space renders the geometry nontrivial (c.f. the Reissner-Nordstr\"om black hole in asymptotically flat background). The BTZ black hole's thermodynamic geometry is trivial despite the fact that it is characterized by the (negative) cosmological constant. As a matter of curiosity we compute thermodynamic geometry of these black holes regarding the cosmological constant as a true parameter but no physically significant results can be derived.Comment: Contribution to proceedings of ERE2008, 4 page

Community next steps for making globally unique identifiers work for biocollections data

Biodiversity data is being digitized and made available online at a rapidly increasing rate but current practices typically do not preserve linkages between these data, which impedes interoperation, provenance tracking, and assembly of larger datasets. For data associated with biocollections, the biodiversity community has long recognized that an essential part of establishing and preserving linkages is to apply globally unique identifiers at the point when data are generated in the field and to persist these identifiers downstream, but this is seldom implemented in practice. There has neither been coalescence towards one single identifier solution (as in some other domains), nor even a set of recommended best practices and standards to support multiple identifier schemes sharing consistent responses. In order to further progress towards a broader community consensus, a group of biocollections and informatics experts assembled in Stockholm in October 2014 to discuss community next steps to overcome current roadblocks. The workshop participants divided into four groups focusing on: identifier practice in current field biocollections; identifier application for legacy biocollections; identifiers as applied to biodiversity data records as they are published and made available in semantically marked-up publications; and cross-cutting identifier solutions that bridge across these domains. The main outcome was consensus on key issues, including recognition of differences between legacy and new biocollections processes, the need for identifier metadata profiles that can report information on identifier persistence missions, and the unambiguous indication of the type of object associated with the identifier. Current identifier characteristics are also summarized, and an overview of available schemes and practices is provided

Curation Micro-Services: A Pipeline Metaphor for Repositories

The effective long-term curation of digital content requires expert analysis, policy setting, and decision making, and a robust technical infrastructure that can effect and enforce curation policies and implement appropriate curation activities. Since the number, size, and diversity of content under curation management will undoubtedly continue to grow over time, and the state of curation understanding and best practices relative to that content will undergo a similar constant evolution, one of the overarching design goals of a sustainable curation infrastructure is flexibility. In order to provide the necessary flexibility of deployment and configuration in the face of potentially disruptive changes in technology, institutional mission, and user expectation, a useful design metaphor is provided by the Unix pipeline, in which complex behavior is an emergent property of the coordinated action of a number of simple independent components. The decomposition of repository function into a highly granular and orthogonal set of independent but interoperable micro-services is consistent with the principles of prudent engineering practice. Since each micro-service is small and self-contained, they are individually more robust and collectively easier to implement and maintain. By being freely interoperable in various strategic combinations, any number of micro-services-based repositories can be easily constructed to meet specific administrative or technical needs. Importantly, since these repositories are purposefully built from policy neutral and protocol and platform independent components to provide the function minimally necessary for a specific context, they are not constrained to conform to an infrastructural monoculture of prepackaged repository solutions. The University of California Curation Center has developed an open source micro-services infrastructure that is being used to manage the diverse digital collections of the ten campus University system and a number of non-university content partners. This paper provides a review of the conceptual design and technical implementation of this micro-services environment, a case study of initial deployment, and a look at ongoing micro-services developments

Curation Micro-Services: A Pipeline Metaphor for Repositories

The effective long-term curation of digital content requires expert analysis, policy setting, and decision making, and a robust technical infrastructure that can effect and enforce curation policies and implement appropriate curation activities. Since the number, size, and diversity of content under curation management will undoubtedly continue to grow over time, and the state of curation understanding and best practices relative to that content will undergo a similar constant evolution, one of the overarching design goals of a sustainable curation infrastructure is flexibility. In order to provide the necessary flexibility of deployment and configuration in the face of potentially disruptive changes in technology, institutional mission, and user expectation, a useful design metaphor is provided by the Unix pipeline, in which complex behavior is an emergent property of the coordinated action of a number of simple independent components. The decomposition of repository function into a highly granular and orthogonal set of independent but interoperable micro-services is consistent with the principles of prudent engineering practice. Since each micro-service is small and self-contained, they are individually more robust and collectively easier to implement and maintain. By being freely interoperable in various strategic combinations, any number of micro-services-based repositories can be easily constructed to meet specific administrative or technical needs. Importantly, since these repositories are purposefully built from policy neutral and protocol and platform independent components to provide the function minimally necessary for a specific context, they are not constrained to conform to an infrastructural monoculture of prepackaged repository solutions. The University of California Curation Center has developed an open source micro-services infrastructure that is being used to manage the diverse digital collections of the ten campus University system and a number of non-university content partners. This paper provides a review of the conceptual design and technical implementation of this micro-services environment, a case study of initial deployment, and a look at ongoing micro-services developments

Seismic Refraction Study of a Buried Valley Near Peninsula, Summit County

Author Institution: Department of Geology, University of AkronA portion of the buried preglacial Akron River valley in northern Summit County was investigated using the seismic refraction method with a BISON 6-channel model 1580 seismograph and a mechanical shock source. From 42 traverses, we gained depth information that permitted construction of an improved structural contour map of bedrock topography. The buried Akron River valley is located in approximately the same position as described by Smith and White (1953), but we determined that it is much narrower than they had estimated with a steep V-shaped bottom portion and gently sloping shoulders. The approximate depth to bedrock over the valley axis is 500 ft. The seismic data further indicated 2 types of valley fill: a lower layer of probably Wisconsinan glacial material with P-wave velocity of 5700 =*= 1400 ft/sec and a thinner, discontinuous upper layer of uncertain nature with P-wave velocity of 2600^600 ft/sec. The weathered zone ranges in thickness from 4 ft to 32 ft and has a seismic velocity of 800 ± 160 ft/sec. Bedrock seismic velocities were 12000=^=2000 ft/sec, appropriate for shale or sandstone