arXiv subjects

Carl Lagoze

Publications and source records attributed to Carl Lagoze.

At least 19 recordsLinked to original sources

arXiv2013

Flexible and Extensible Digital Object and Repository Architecture (FEDORA)

We describe a digital object and respository architecture for storing and disseminating digital library content. The key features of the architecture are: (1) support for heterogeneous data types; (2) accommodation of new types as they emerge; (3) aggregation of mixed, possibly distributed, data into complex objects; (4) the ability to specify multiple content disseminations of these objects; and (5) the ability to associate rights management schemes with these disseminations. This architecture is being implemented in the context of a broader research project to develop next-generation service modules for a layered digital library architecture.

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arXiv2013

Policy-Carrying, Policy-Enforcing Digital Objects

We describe the motivation for moving policy enforcement for access control down to the digital object level. The reasons for this include handling of item-specific behaviors, adapting to evolution of digital objects, and permitting objects to move among repositories and portable devices. We then describe our experiments that integrate the Fedora architecture for digital objects and repositories and the PoET implementation of security automata to effect such objectcentric policy enforcement.

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arXiv2013

Web Synchronization Simulations using the ResourceSync Framework

Maintenance of multiple, distributed up-to-date copies of collections of changing Web resources is important in many application contexts and is often achieved using ad hoc or proprietary synchronization solutions. ResourceSync is a resource synchronization framework that integrates with the Web architecture and leverages XML sitemaps. We define a model for the ResourceSync framework as a basis for understanding its properties. We then describe experiments in which simulations of a variety of synchronization scenarios illustrate the effects of model configuration on consistency, latency, and data transfer efficiency. These results provide insight into which congurations are appropriate for various application scenarios.

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arXiv2013

ResourceSync: Leveraging Sitemaps for Resource Synchronization

Many applications need up-to-date copies of collections of changing Web resources. Such synchronization is currently achieved using ad-hoc or proprietary solutions. We propose ResourceSync, a general Web resource synchronization protocol that leverages XML Sitemaps. It provides a set of capabilities that can be combined in a modular manner to meet local or community requirements. We report on work to implement this protocol for arXiv.org and also provide an experimental prototype for the English Wikipedia as well as a client API.

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arXiv2013

RESLVE: Leveraging User Interest to Improve Entity Disambiguation on Short Text

We address the Named Entity Disambiguation (NED) problem for short, user-generated texts on the social Web. In such settings, the lack of linguistic features and sparse lexical context result in a high degree of ambiguity and sharp performance drops of nearly 50% in the accuracy of conventional NED systems. We handle these challenges by developing a model of user-interest with respect to a personal knowledge context; and Wikipedia, a particularly well-established and reliable knowledge base, is used to instantiate the procedure. We conduct systematic evaluations using individuals' posts from Twitter, YouTube, and Flickr and demonstrate that our novel technique is able to achieve substantial performance gains beyond state-of-the-art NED methods.

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arXiv2013

Semantic Tagging on Historical Maps

Tags assigned by users to shared content can be ambiguous. As a possible solution, we propose semantic tagging as a collaborative process in which a user selects and associates Web resources drawn from a knowledge context. We applied this general technique in the specific context of online historical maps and allowed users to annotate and tag them. To study the effects of semantic tagging on tag production, the types and categories of obtained tags, and user task load, we conducted an in-lab within-subject experiment with 24 participants who annotated and tagged two distinct maps. We found that the semantic tagging implementation does not affect these parameters, while providing tagging relationships to well-defined concept definitions. Compared to label-based tagging, our technique also gathers positive and negative tagging relationships. We believe that our findings carry implications for designers who want to adopt semantic tagging in other contexts and systems on the Web.

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arXiv2013

The Extraction of Community Structures from Publication Networks to Support Ethnographic Observations of Field Differences in Scientific Communication

The scientific community of researchers in a research specialty is an important unit of analysis for understanding the field specific shaping of scientific communication practices. These scientific communities are, however, a challenging unit of analysis to capture and compare because they overlap, have fuzzy boundaries, and evolve over time. We describe a network analytic approach that reveals the complexities of these communities through examination of their publication networks in combination with insights from ethnographic field studies. We suggest that the structures revealed indicate overlapping sub- communities within a research specialty and we provide evidence that they differ in disciplinary orientation and research practices. By mapping the community structures of scientific fields we aim to increase confidence about the domain of validity of ethnographic observations as well as of collaborative patterns extracted from publication networks thereby enabling the systematic study of field differences. The network analytic methods presented include methods to optimize the delineation of a bibliographic data set in order to adequately represent a research specialty, and methods to extract community structures from this data. We demonstrate the application of these methods in a case study of two research specialties in the physical and chemical sciences.

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arXiv2011

Resolving Author Name Homonymy to Improve Resolution of Structures in Co-author Networks

We investigate how author name homonymy distorts clustered large-scale co-author networks, and present a simple, effective, scalable and generalizable algorithm to ameliorate such distortions. We evaluate the performance of the algorithm to improve the resolution of mesoscopic network structures. To this end, we establish the ground truth for a sample of author names that is statistically representative of different types of nodes in the co-author network, distinguished by their role for the connectivity of the network. We finally observe that this distinction of node roles based on the mesoscopic structure of the network, in combination with a quantification of author name commonality, suggests a new approach to assess network distortion by homonymy and to analyze the reduction of distortion in the network after disambiguation, without requiring ground truth sampling.

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arXiv2009

Adding eScience Assets to the Data Web

Aggregations of Web resources are increasingly important in scholarship as it adopts new methods that are data-centric, collaborative, and networked-based. The same notion of aggregations of resources is common to the mashed-up, socially networked information environment of Web 2.0. We present a mechanism to identify and describe aggregations of Web resources that has resulted from the Open Archives Initiative - Object Reuse and Exchange (OAI-ORE) project. The OAI-ORE specifications are based on the principles of the Architecture of the World Wide Web, the Semantic Web, and the Linked Data effort. Therefore, their incorporation into the cyberinfrastructure that supports eScholarship will ensure the integration of the products of scholarly research into the Data Web.

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arXiv2008

A Web-Based Resource Model for eScience: Object Reuse & Exchange

Work in the Open Archives Initiative - Object Reuse and Exchange (OAI-ORE) focuses on an important aspect of infrastructure for eScience: the specification of the data model and a suite of implementation standards to identify and describe compound objects. These are objects that aggregate multiple sources of content including text, images, data, visualization tools, and the like. These aggregations are an essential product of eScience, and will become increasingly common in the age of data-driven scholarship. The OAI-ORE specifications conform to the core concepts of the Web architecture and the semantic Web, ensuring that applications that use them will integrate well into the general Web environment.

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arXiv2008

Object Re-Use & Exchange: A Resource-Centric Approach

The OAI Object Reuse and Exchange (OAI-ORE) framework recasts the repository-centric notion of digital object to a bounded aggregation of Web resources. In this manner, digital library content is more integrated with the Web architecture, and thereby more accessible to Web applications and clients. This generalized notion of an aggregation that is independent of repository containment conforms more closely with notions in eScience and eScholarship, where content is distributed across multiple services and databases. We provide a motivation for the OAI-ORE project, review previous interoperability efforts, describe draft ORE specifications and report on promising results from early experimentation that illustrate improved interoperability and reuse of digital objects.

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arXiv2006

Pathways: Augmenting interoperability across scholarly repositories

In the emerging eScience environment, repositories of papers, datasets, software, etc., should be the foundation of a global and natively-digital scholarly communications system. The current infrastructure falls far short of this goal. Cross-repository interoperability must be augmented to support the many workflows and value-chains involved in scholarly communication. This will not be achieved through the promotion of single repository architecture or content representation, but instead requires an interoperability framework to connect the many heterogeneous systems that will exist. We present a simple data model and service architecture that augments repository interoperability to enable scholarly value-chains to be implemented. We describe an experiment that demonstrates how the proposed infrastructure can be deployed to implement the workflow involved in the creation of an overlay journal over several different repository systems (Fedora, aDORe, DSpace and arXiv).

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arXiv2006

Mining Generalized Graph Patterns based on User Examples

There has been a lot of recent interest in mining patterns from graphs. Often, the exact structure of the patterns of interest is not known. This happens, for example, when molecular structures are mined to discover fragments useful as features in chemical compound classification task, or when web sites are mined to discover sets of web pages representing logical documents. Such patterns are often generated from a few small subgraphs (cores), according to certain generalization rules (GRs). We call such patterns "generalized patterns"(GPs). While being structurally different, GPs often perform the same function in the network. Previously proposed approaches to mining GPs either assumed that the cores and the GRs are given, or that all interesting GPs are frequent. These are strong assumptions, which often do not hold in practical applications. In this paper, we propose an approach to mining GPs that is free from the above assumptions. Given a small number of GPs selected by the user, our algorithm discovers all GPs similar to the user examples. First, a machine learning-style approach is used to find the cores. Second, generalizations of the cores in the graph are computed to identify GPs. Evaluation on synthetic data, generated using real cores and GRs from biological and web domains, demonstrates effectiveness of our approach.

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arXiv2006

Representing Contextualized Information in the NSDL

The NSDL (National Science Digital Library) is funded by the National Science Foundation to advance science and match education. The inital product was a metadata-based digital library providing search and access to distributed resources. Our recent work recognizes the importance of context - relations, metadata, annotations - for the pedagogical value of a digital library. This new architecture uses Fedora, a tool for representing complex content, data, metadata, web-based services, and semantic relationships, as the basis of an information network overlay (INO). The INO provides an extensible knowl-edge base for an expanding suite of digital library services.

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arXiv2006

Metadata aggregation and "automated digital libraries": A retrospective on the NSDL experience

Over three years ago, the Core Integration team of the National Science Digital Library (NSDL) implemented a digital library based on metadata aggregation using Dublin Core and OAI-PMH. The initial expectation was that such low-barrier technologies would be relatively easy to automate and administer. While this architectural choice permitted rapid deployment of a production NSDL, our three years of experience have contradicted our original expectations of easy automation and low people cost. We have learned that alleged "low-barrier" standards are often harder to deploy than expected. In this paper we report on this experience and comment on the general cost, the functionality, and the ultimate effectiveness of this architecture.

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arXiv2005

Fedora: An Architecture for Complex Objects and their Relationships

The Fedora architecture is an extensible framework for the storage, management, and dissemination of complex objects and the relationships among them. Fedora accommodates the aggregation of local and distributed content into digital objects and the association of services with objects. This al-lows an object to have several accessible representations, some of them dy-namically produced. The architecture includes a generic RDF-based relation-ship model that represents relationships among objects and their components. Queries against these relationships are supported by an RDF triple store. The architecture is implemented as a web service, with all aspects of the complex object architecture and related management functions exposed through REST and SOAP interfaces. The implementation is available as open-source soft-ware, providing the foundation for a variety of end-user applications for digital libraries, archives, institutional repositories, and learning object systems.

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arXiv2005

An Information Network Overlay Architecture for the NSDL

We describe the underlying data model and implementation of a new architecture for the National Science Digital Library (NSDL) by the Core Integration Team (CI). The architecture is based on the notion of an information network overlay. This network, implemented as a graph of digital objects in a Fedora repository, allows the representation of multiple information entities and their relationships. The architecture provides the framework for contextualization and reuse of resources, which we argue is essential for the utility of the NSDL as a tool for teaching and learning.

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arXiv2002

Core Services in the Architecture of the National Digital Library for Science Education (NSDL)

We describe the core components of the architecture for the (NSDL) National Science, Mathematics, Engineering, and Technology Education Digital Library. Over time the NSDL will include heterogeneous users, content, and services. To accommodate this, a design for a technical and organization infrastructure has been formulated based on the notion of a spectrum of interoperability. This paper describes the first phase of the interoperability infrastructure including the metadata repository, search and discovery services, rights management services, and user interface portal facilities.

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