A Basis for Interactive Schema Merging

We present a technique for merging the schemas of heterogeneous databases that generalizes to several different data models, and show how it can be used in an interactive program that merges Entity-Relationship diagrams. Given a collection of schemas to be merged, the user asserts the correspondence between entities and relationships in the various schemas by defining "isa" relations between them. These assertions are then considered to be elementary schemas, and are combined with the elementary schemas in the merge. Since the method defines the merge to be the join in an information ordering on schemas, it is a commutative and associative operation, which means that the merge is defined independent of the order in which schemas are presented. We briefly describe a prototype interactive schema merging tool that has been built on these principles. Keywords: schemas, merging, semantic data models, entity-relationship data models, inheritance 1 Introduction Schema merging is the proble..

Relational Foundations For Functorial Data Migration

We study the data transformation capabilities associated with schemas that are presented by directed multi-graphs and path equations. Unlike most approaches which treat graph-based schemas as abbreviations for relational schemas, we treat graph-based schemas as categories. A schema $S$ is a finitely-presented category, and the collection of all $S$-instances forms a category, $S$-inst. A functor $F$ between schemas $S$ and $T$, which can be generated from a visual mapping between graphs, induces three adjoint data migration functors, $\Sigma_F:S$-inst$\to T$-inst, $\Pi_F: S$-inst $\to T$-inst, and $\Delta_F:T$-inst $\to S$-inst. We present an algebraic query language FQL based on these functors, prove that FQL is closed under composition, prove that FQL can be implemented with the select-project-product-union relational algebra (SPCU) extended with a key-generation operation, and prove that SPCU can be implemented with FQL

Shape Expressions Schemas

We present Shape Expressions (ShEx), an expressive schema language for RDF designed to provide a high-level, user friendly syntax with intuitive semantics. ShEx allows to describe the vocabulary and the structure of an RDF graph, and to constrain the allowed values for the properties of a node. It includes an algebraic grouping operator, a choice operator, cardinalitiy constraints for the number of allowed occurrences of a property, and negation. We define the semantics of the language and illustrate it with examples. We then present a validation algorithm that, given a node in an RDF graph and a constraint defined by the ShEx schema, allows to check whether the node satisfies that constraint. The algorithm outputs a proof that contains trivially verifiable associations of nodes and the constraints that they satisfy. The structure can be used for complex post-processing tasks, such as transforming the RDF graph to other graph or tree structures, verifying more complex constraints, or debugging (w.r.t. the schema). We also show the inherent difficulty of error identification of ShEx

Assessment and treatment of distorted schemas in sexual offenders

The aim of this review is to examine the literature related to the assessment and treatment of sex offenders’ distorted schemas. Where appropriate, the review draws upon current insights from the field of social cognition to aid in the critical evaluation of the findings. First, the review considers the various different methodologies for assessing distorted schemas, discussing their strengths and limitations. Second, the review examines the work related to the treatment of sex offenders’ schemas. Suggestions for future research, and the implications for clinical practice, are highlighted in the article

Ensuring Query Compatibility with Evolving XML Schemas

During the life cycle of an XML application, both schemas and queries may change from one version to another. Schema evolutions may affect query results and potentially the validity of produced data. Nowadays, a challenge is to assess and accommodate the impact of theses changes in rapidly evolving XML applications. This article proposes a logical framework and tool for verifying forward/backward compatibility issues involving schemas and queries. First, it allows analyzing relations between schemas. Second, it allows XML designers to identify queries that must be reformulated in order to produce the expected results across successive schema versions. Third, it allows examining more precisely the impact of schema changes over queries, therefore facilitating their reformulation

The role of unsafe schemas and insecure attachment responses in PTSD symptomatology after traumatic adulthood experiences : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University

The most common disorder resulting from trauma is posttraumatic stress disorder (PTSD). Empirical research affirms the effectiveness of several cognitive-behavioural therapies in treating PTSD symptomatology; however additional complications including interpersonal difficulties, treatment resistance and the simultaneous development of other disorders, such as depression and alcoholism, often impedes the effective treatment of PTSD. The aim of the present study was to provide a deeper understanding of specific cognitive-emotional schemas related to PTSD symptomatology. Unsafe schemas involving perceptions of severe threat regarding a person's sense of safety, control and invulnerability; and internal working models (IWMs) involving generalized attachment related perceptions and feelings regarding the self and others, were the schemas that were investigated. Participants were volunteers from the general community, responding to written or verbal advertisements regarding the study. A total of 188 participants filled out four self-report questionnaires about their own psychological and behavioural responses to a past traumatic event. The questionnaires gathered demographic data, details about the traumatic event and information about the degree to which PTSD symptoms, unsafe schemas and IWMs were elicited. The findings indicated that a threatened sense of control was the highest significant predictor for both intensity and length of time of PTSD symptoms. Although moderately strong significant correlations were found between PTSD symptomatology and the other unsafe schemas (threatened safety and threatened invulnerability) these variables did not predict intensity or length of time that PTSD symptoms were experienced. Negative IWMs of others predicted both intensity and length of time of PTSD, whereas negative IWMs of the self predicted only intensity of PTSD symptoms.Positive IWMs did not significantly predict PTSD symptomatology. Several other statistical comparisons confirmed that unsafe schemas and negative IWMs of others both appear to play a significant role in chronicity of post-traumatic symptomatology. The findings generated several important practical implications for the treatment of traumatized individuals, which were discussed along with limitations of the study and directions for future research. Potential explanations for the findings of the research in relation to previous research findings were also proposed