Search results for "schema."

Glass transitions and scaling laws within an alternative mode-coupling theory

2015

Idealized glass transitions are discussed within an alternative mode-coupling theory (TMCT) proposed by Tokuyama [Physica A 395, 31 (2014)]. This is done in order to identify common ground with and differences from the conventional mode-coupling theory (MCT). It is proven that both theories imply the same scaling laws for the transition dynamics, which are characterized by two power-law decay functions and two diverging power-law time scales. However, the values for the corresponding anomalous exponents calculated within both theories differ from each other. It is proven that the TMCT, contrary to the MCT, does not describe transitions with continuously vanishing arrested parts of the corre…

Embodiment and American Sign Language

2016

Little is known about how individual signs that occur in naturally produced signed languages are recognized. Here we examine whether sign understanding may be grounded in sensorimotor properties by evaluating a signer’s ability to make lexical decisions to American Sign Language (ASL) signs that are articulated either congruent with or incongruent with the observer’s own handedness. Our results show little evidence for handedness congruency effects for native signers’ perception of ASL, however handedness congruency effects were seen in non-native late learners of ASL and hearing ASL-English bilinguals. The data are compatible with a theory of sign recognition that makes reference to intern…

The role of recruitment agencies in imagining and producing the ‘good’ migrant

2013

This paper focuses on representations of labour migrants and interrogates how such imaginaries shape migrant recruitment and employment regimes. The recruitment and employment of labour migrants inevitably involves a range of knowledge practices that affect who is recruited, from where and for what purposes. In particular, this paper seeks to advance understandings of how images of ‘bodily goodness’ are represented graphically and how perceptions of migrant workers influence the recruitment of workers to the UK from Latvia. The research described in this paper is based on interviews with recruitment agencies, employers and policy makers carried out in Latvia in 2011. The analysis results in…

Expectancy in Sami Yoiks revisited: The role of data-driven and schema-driven knowledge in the formation of melodic expectations

2009

This study extends a previous study concerning melodic expectations in North Sami yoiks (Krumhansl et al., 2000) in which a comparison between expert and non-expert listeners demonstrated the existence of a core set of principles governing melodic expectancies. The previous findings are reconsidered using non-Western listeners (traditional healers from South Africa) in a modeling investigation. Comparison of different models made it possible to separate the role of data-driven and schema-driven models in melodic expectancies and to reveal any possible Western bias in previous studies. The results of the experiment, in which African listeners rated the fitness of probe-tones as continuation…

Probabilistic techniques for bridging the semantic gap in schema alignment

Connecting pieces of informations from heterogeneous sources sharing the same domain is an open challenge in Semantic Web, Big Data and business communities. The main problem in this research area is to bridge the expressiveness gap between relational databases and ontologies. In general, an ontology is more expressive and captures more semantic information behind data than a relational database does. On the other side, databases are the most common used persistent storage system and they grant benefits such as security and data integrity but they need to be managed by expert users. The problem is quite significant above all when enterprise or corporate ontologies are used to share infomation…

Metadata to Support Data Warehouse Evolution

2009

The focus of this chapter is metadata necessary to support data warehouse evolution. We present the data warehouse framework that is able to track evolution process and adapt data warehouse schemata and data extraction, transformation, and loading (ETL) processes. We discuss the significant part of the framework, the metadata repository that stores information about the data warehouse, logical and physical schemata and their versions. We propose the physical implementation of multiversion data warehouse in a relational DBMS. For each modification of a data warehouse schema, we outline the changes that need to be made to the repository metadata and in the database.

Spatio-temporal Schema Integration with Validation: A Practical Approach

2005

We propose to enhance a schema integration process with a validation phase employing logic-based data models. In our methodology, we validate the source schemas against the data model; the inter-schema mappings are validated against the semantics of the data model and the syntax of the correspondence language. In this paper, we focus on how to employ a reasoning engine to validate spatio-temporal schemas and describe where the reasoning engine is plugged into our integration methodology. The validation phase distinguishes our integration methodology from other approaches. We shift the emphasis on automation from the a priori discovery to the a posteriori checking of the inter-schema mapping…

Extending a Metamodel for Formalization of Data Warehouse Requirements

2014

In performance measurement systems that are built on top of a data warehouse, the information requirements in natural language are different performance indicators that should be stored and analyzed. We use the requirement formalization metamodel to create a formal requirement repository out of information requirements in natural language. In the course of this research we tested the compatibility of the existing requirement formalization metamodel applying it to a set of over 150 requirements for the currently operating data warehouse project. As a result, we extended the formal specification of information requirements with some additional classes like themes, grouping, and requirement pr…

Migration of Relational Database to Document-Oriented Database: Structure Denormalization and Data Transformation

2015

Relational databases remain the leading data storage technology. Nevertheless, many companies want to reduce operating expenses, to make scalable applications that use cloud computing technologies. Use of NoSQL database is one of the possible solutions, and it is forecasted that the NoSQL market will be growing at a CAGR of approximately 50 percent over the next five years. The paper offers a solution for quick data migration from a relational database into a document-oriented database. We have created semi-automatically two logical levels over physical data. Users can refine generated logical data model and configure data migration template for each needed document. Data migration features…

Query-Driven Method for Improvement of Data Warehouse Conceptual Model

2013

We propose a query-driven method that elicits the information requirements from existing queries on data sources and their usage statistics. Our method presumes that the queries against the source database reflect the analysis needs of users. We use this method to recommend changes to the existing data warehouse schemata. In our method, we take advantage of the schema versioning approach to reflect all changes that occur in the analysed process, and we analyse the activity of users in the source system, rather than changes in physical data structure, to infer the necessary improvements to the data warehouse schema.