1,721,003 research outputs found
Exact Tests via Complete Enumeration: A Distributed Computing Approach
No full textThe analysis of categorical data often leads to the analysis of a contingency table. For large samples, asymptotic approximations are sufficient when calculating p-values, but for small samples the tests can be unreliable. In these situations an exact test should be considered. This bases the test on the exact distribution of the test statistic. Sampling techniques can be used to estimate the distribution. Alternatively, the distribution can be found by complete enumeration. A new algorithm is developed that enables a model to be defined by a model matrix, and all tables that satisfy the model are found. This provides a more efficient enumeration mechanism for complex models and extends the range of models that can be tested. The technique can lead to large calculations and a distributed version of the algorithm is developed that enables a number of machines to work efficiently on the same problem
PROV-JSONLD: a JSON and linked data representation for provenance
No full textIn this paper, we propose a representation for PROV in JSON-LD, the JSON format for Linked Data, called PROV-JSONLD. As a JSON-based format, this provenance representation can be readily consumed by Web applications currently supporting JSON. As a Linked Data format, at the same time, it also represents provenance data in RDF using the PROV ontology. Hence, it is suitable for usages in both the Web and the Semantic Web
Exact tests for two-way symmetric contingency tables
No full textA two-way contingency table in which both variables have the same categories is termed a symmetric table. In many applications, because of the social processes involved, most of the observations lie on the main diagonal and the off-diagonal counts are small. For these tables, the model of independence is implausible and interest is then focussed on the off-diagonal cells and the models of quasi-independence and quasi-symmetry. For ordinal variables, a linear-by-linear association model can be used to model the interaction structure. For sparse tables, large-sample goodness-of-fit tests are often unreliable and one should use an exact test. In this paper, we review exact tests and the computing problems involved. We propose new recursive algorithms for exact goodness-of-fit tests of quasi-independence, quasi-symmetry, linear-by-linear association and some related models. We propose that all computations be carried out using symbolic computation and rational arithmetic in order to calculate the exact p-values accurately and describe how we implemented our proposals. Two examples are presented
The PROV-JSON serialization
No full textThis document specifies a JSON representation for the PROV Data Model, called PROV-JSON. It provides a compact and faithful representation of PROV that supports fast data look-up and is particularly suitable for interchanging PROV documents between web services and clients
Files and data for Intermediate Notation for Provenance and Workflow Reproducibility
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Exploring the Relationship Between FOHM and RDF
No full textOne of the results of the Open Hypermedia work of the last decade was the Fundamental Open Hypermedia Model (FOHM) capable of representing contextual structure from a variety of hypermedia domains. As the Semantic Web becomes more important it is interesting to compare its metadata language, the Resource Description Framework (RDF), with a model such as FOHM. In this paper we examine the relationship between FOHM and RDF to see if they have equivalent expressivity. In particular we look at whether you can represent FOHM structures in RDF, either as a direct mapping from FOHM to the RDF vocabulary or by defining a FOHM schema in RDFS or OWL
MUD Slinging: Virtual Orchestration of Physical Interactions
No full textIn this paper we look at two scenarios of physical-digital interaction. The first is an Ambient Wood, forming a sub project of the Equator IRC researching playful learning through novel interaction. The second, a meeting room, constructed for the FEEL project in which the management of intrusive notifications is desired. We look at how these scenarios can be modelled using a Multi-User Dungeon (MUD), providing orchestration tools for the interactions taking place, with consideration to other mechanisms available
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