2 resultados para schema a soglia Shamir Blakley schema di condivisione di segreti perfetto

em University of Queensland eSpace - Australia


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Geospatio-temporal conceptual models provide a mechanism to explicitly represent geospatial and temporal aspects of applications. Such models, which focus on both what and when/where, need to be more expressive than conventional conceptual models (e.g., the ER model), which primarily focus on what is important for a given application. In this study, we view conceptual schema comprehension of geospatio-temporal data semantics in terms of matching the external problem representation (that is, the conceptual schema) to the problem-solving task (that is, syntactic and semantic comprehension tasks), an argument based on the theory of cognitive fit. Our theory suggests that an external problem representation that matches the problem solver's internal task representation will enhance performance, for example, in comprehending such schemas. To assess performance on geospatio-temporal schema comprehension tasks, we conducted a laboratory experiment using two semantically identical conceptual schemas, one of which mapped closely to the internal task representation while the other did not. As expected, we found that the geospatio-temporal conceptual schema that corresponded to the internal representation of the task enhanced the accuracy of schema comprehension; comprehension time was equivalent for both. Cognitive fit between the internal representation of the task and conceptual schemas with geospatio-temporal annotations was, therefore, manifested in accuracy of schema comprehension and not in time for problem solution. Our findings suggest that the annotated schemas facilitate understanding of data semantics represented on the schema.

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We investigated cross-cultural differences in the factor structure and psychometric properties of the 75-item Young Schema Questionnaire-Short Form (YSQ-SF). Participants were 833 South Korean and 271 Australian undergraduate students. The South Korean sample was randomly divided into two sub-samples. Sample A was used for Exploratory Factor Analysis (EFA) and sample B was used for Confirmatory Factor Analysis (CFA). EFA for the South Korean sample revealed a 13-factor solution to be the best fit for the data, and CFA on the data from sample B confirmed this result. CFA on the data from the Australian sample also revealed a 13-factor solution. The overall scale of the YSQ-SF demonstrated a high level of internal consistency in the South Korean and Australian groups. Furthermore, adequate internal consistencies for all subscales in the South Korean and Australian samples were demonstrated. In conclusion, the results showed that YSQ-SF with 13 factors has good psychometric properties and reliability for South Korean and Australian University students. Korean samples had significantly higher YSD scores on most of the 13 subscales than the Australian sample. However, limitations of the current study preclude the generalisability of the findings to beyond undergraduate student populations. (c) 2006 Elsevier B.V. All rights reserved.