Modeling spatial covariance functions

Covariance modeling plays a key role in the spatial data analysis as it provides important information about the dependence structure of underlying processes and determines performance of spatial prediction. Various parametric models have been developed to accommodate the idiosyncratic features of a given dataset. However, the parametric models may impose unjustified restrictions to the covariance structure and the procedure of choosing a specific model is often ad-hoc. In the first part of the dissertation, a new nonparametric covariance model that can avoid the choice of parametric forms is proposed. The estimator is obtained via a nonparametric approximation of completely monotone functions. It is easy to implement and simulation study shows it outperforms the parametric models when there is no clear information on model specification. Two real datasets are analyzed to illustrate the proposed approach and provide further comparison between the nonparametric and parametric models. ^ Most spatial covariance models assume that the dependence becomes stronger when two locations are closer to each other and thus assume that the dependence is negligible when two locations are far apart from one another. However long-distance connection can occur in climate variables through, for example, high altitude winds or large-scale atmospheric waves propagation. This phenomenon is called teleconnection and often considered to be responsible for extreme weather events occurring simultaneously around the world. In the second part of the dissertation, a nonstationary spatial covariance model for long-distance dependence is proposed. The model allows the spatial dependence to vary with time so that temporal dynamics of the teleconnection phenomenon can be captured. The model is applied to analyze teleconnection between sea surface temperature of tropical Pacific Ocean and hydrological droughts of North America incurred by the El Niño-Southern Oscillation

Toward a Model of Intercultural Warrant: A Case of the Korean Decimal Classification\u27s Cross-cultural Adaptation of the Dewey Decimal Classification

I examined the Korean Decimal Classification (KDC)\u27s adaptation of the Dewey Decimal Classification (DDC) by comparing the two systems. This case manifests the sociocultural influences on KOSs in a cross-cultural context. I focused my analysis on the changes resulting from the meeting of the two cultures, answering the main research question: “How does KDC adapt DDC in terms of underlying sociocultural perspectives in a classificatory form?” I took a comparative approach and address the main research question in two phases. In Phase 1, quantities of class numbers were analyzed by edition and discipline. The main class with the most consistently high number of class numbers in DDC was the social sciences, while the main class with the most consistently high number of class numbers in KDC was technology. The two main classes are expected to differ in semantic contents or specificities. In Phase 2, patterns of adaptations were analyzed by examining the class numbers, captions, and hierarchical relations within the developed adaptation taxonomy. Implementing the taxonomy as a coding scheme brings two comparative features of classifications: 1) semantic contents determined by captions and quantity of subordinate numbers; and 2) structural arrangement determined by ranks, the broader category, presence and the order of subordinate numbers. Surveying proper forms of adaptation resulted in the development of an adaptation taxonomy that will serve as a framework to account for the conflicts between and harmonization of multiple social and cultural influences in knowledge structures. This study has ramifications in theoretical and empirical foundations for the development of “intercultural warrant” in KOSs

Visualizations of cross-cultural bibliographic classification: comparative studies of the Korean Decimal Classification and the Dewey Decimal Classification

The changes in KO systems induced by sociocultural influences may include those in both classificatory principles and cultural features. The proposed study will examine the Korean Decimal Classification (KDC)’s adaptation of the Dewey Decimal Classification (DDC) by comparing the two systems. This case manifests the sociocultural influences on KOSs in a cross-cultural context. Therefore, the study aims at an in- depth investigation of sociocultural influences by situating a KOS in a cross-cultural environment and examining the dynamics between two classification systems designed to organize information resources in two distinct sociocultural contexts. As a preceding stage of the comparison, the analysis was conducted on the changes that result from the meeting of different sociocultural feature in a descriptive method. The analysis aims to identify variations between the two schemes in comparison of the knowledge structures of the two classifications, in terms of the quantity of class numbers that represent concepts and their relationships in each of the individual main classes. The most effective analytic strategy to show the patterns of the comparison was visualizations of similarities and differences between the two systems. Increasing or decreasing tendencies in the class through various editions were analyzed. Comparing the compositions of the main classes and distributions of concepts in the KDC and DDC discloses the differences in their knowledge structures empirically. This phase of quantitative analysis and visualizing techniques generates empirical evidence leading to interpretation

A Cross-cultural Comparison of Medical Science Subject Classification in the KDC and the DDC

This study reports the preliminary results of a cross-cultural comparison of Medical Science in the Korean Decimal Classification (KDC) and in the Dewy Decimal Classification (DDC). Despite having similar purposes, to serve the public and emphasize the significance of standardization in medical science, a comparison of the two classification systems shows the influences of social and cultural inferences of classification systems in medicine

Specificity and exhaustivity of bibliographic classifications – A cross-cultural comparison with text analytic approach

The current study aims to detect sociocultural differences implied in the classification systems, employing text analytic techniques. By comparing Korean Decimal Classification (KDC) and Dewey Decimal Classification (DDC), this study probes the gaps in exhaustivity and specificity in the two classification systems developed in distant social and cultural contexts. A computer-aided quantitative approach in cross-cultural comparison of Knowledge Organization Systems (KOSs) is a relatively new attempt. Besides the finding of the study will demonstrate how to utilize classification as a large textual data set and an automated classification reading

Is User Studies User-oriented? Domain analytic approach to User Studies in Information Organization

In this study, the use of user studies in information organization and a desired future direction can be visualized by investigating how user studies have been shaped in ISKO (International Society of Knowledge Organization) proceedings from 1990 to 2012. Also, the author suggested a holistic view of user in information system.ye

Exploring the core: After almost a decade of IT integration into LIS education

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