Fuzzy Spatiotemporal Data Research Articles

A fine-grained RDF graph model for fuzzy spatiotemporal data

The uncertainty and spatiotemporal dynamics of information necessitate the urgent modeling of fuzzy spatiotemporal knowledge across various applications, with the Resource Description Framework (RDF) serving as a widely recognized data representation model. Existing models suffer from incomplete semantic representation and poor robustness in modeling fuzzy spatiotemporal data, e.g., lack of fuzziness in spatiotemporal semantics; lack of altitude in spatial semantics. Meanwhile, the algebraic framework regarding the model has not been investigated. Thus, in this paper, we first propose a new fine-grained fuzzy spatiotemporal RDF model. This model can represent fine-grained uncertain spatiotemporal semantics that may be associated with any element of a spatiotemporal RDF. We further define its graph algebraic operations. Note that we demonstrate the use of the algebraic operations for fuzzy spatiotemporal RDF querying. Finally, we establish a set of transformation rules for SPARQL query syntax to algebraic operations in fuzzy spatiotemporal RDF. In addition, we used experiments to evaluate the validity and rationality of our model.

A general characterization of integrating and querying heterogeneous fuzzy spatiotemporal XML data

A general characterization of integrating and querying heterogeneous fuzzy spatiotemporal XML data

Fixing the inconsistencies of continuous changing operations in fuzzy spatiotemporal RDF graph

Fuzzy spatiotemporal data models have been used to support spatial and temporal knowledge representation and reasoning in the presence of fuzziness. In the meantime, Resource Description Framework (RDF), the most relevant data representation and exchange standard on Semantic Web, has become a trend for representing fuzzy spatiotemporal data. However, due to the dynamic changes of fuzzy spatiotemporal data, fuzzy spatiotemporal RDF graphs are more likely to violate predefined spatial and temporal constraints than the general RDF graph, which causes data inconsistencies. At present, consistency problems in RDF graphs have been widely studied, but their studies consider only discrete changing operations of fuzzy spatiotemporal data, while researches on consistencies of continuous changing operations are still open issues. In this paper, we study the types of inconsistency caused by continuous changing operations and propose the corresponding fixing rules to the problems of inconsistencies. Then, we propose the corresponding fixing approaches to checking and fixing fuzzy spatiotemporal RDF graphs according to the inconsistent states. Finally, the experimental results show that our proposed algorithms can significantly fix inconsistencies of continuous changing operations in fuzzy spatiotemporal RDF graphs.

Fuzzy Spatiotemporal Data Modeling and Operations in RDF

With the emergence of a large number of fuzzy spatiotemporal data on the Web, how to represent and operate fuzzy spatiotemporal data has become an important research issue. Meanwhile, the Resource Description Framework (RDF) is a standard data and knowledge description language of the Semantic Web and has been applied in many application areas, such as geographic information systems and meteorological systems. In this paper, a model for representing fuzzy spatiotemporal data is proposed and a set of algebraic operations for the model are investigated. First, a representation method of fuzzy spatiotemporal RDF data and a fuzzy spatiotemporal RDF graph model are proposed. In addition, a formal fuzzy spatiotemporal RDF algebra is proposed and a set of algebraic operations for manipulating fuzzy spatiotemporal RDF data are developed. The algebraic operations include: set operation, selection operation, projection operation, join operation, and construction operation. Finally, the existing SPARQL query language is extended and an example that shows how to apply the proposed algebraic operations to capture the queries expressed by the extended SPARQL query language is given.

Adaptive query relaxation and top‐ k result sorting of fuzzy spatiotemporal data based on XML

With the increasing popularity of Extensible Markup Language (XML) for data representation, there is a lot of interest in searching XML data. Due to the structural heterogeneity of XML, it is daunting for users to formulate exact queries and search for accurate answers. Especially when performing queries on fuzzy spatiotemporal data, the imprecision and uncertainty of information make the amount of query results is small or even empty. In this case, query relaxation is necessary. Existing efforts are mainly made on expanding simple queries. Once there are multiple conditions in the query, the existing algorithms often have poor performance. To address this problem, we first propose an adaptive query relaxation algorithm based on XML, which can handle complex queries efficiently. The approach does not depend on any specific domain or user, it can adaptively relax the initial query requirements, and classify the results into two sets after query relaxation. Moreover, the algorithm prestores the potential matching objects in the auxiliary structure, which provides support for efficient query. In addition, after query relaxation, we present the result sorting algorithm to address the problem of information overload. Finally, we report experimental results to show that our algorithms are superior to previous approaches.

Fixing the inconsistencies in fuzzy spatiotemporal RDF graph

Since an increasing number of applications have urgent requirements for the management of fuzzy spatiotemporal information, it is challenging to model fuzzy spatiotemporal data. On the other hand, because Resource Description Framework (RDF) benefits greatly from web data, linked data, and knowledge graph, it has been widely accepted and has rapidly become a new choice to model and represent data in many application domains. The advent of RDF seems to provide an opportunity for dealing with fuzzy spatiotemporal data. However, RDF data is subject to continuously changing operations so that they may violate the integrity constraints and cause inconsistencies. In order to solve these problems, we propose an extended RDF model that can represent fuzzy spatiotemporal data, and then present the structure of fuzzy spatiotemporal data in RDF graph. After studying the constraint conditions of fuzzy spatiotemporal data in RDF graph, we propose the corresponding fixing rules and algorithms to detect and repair the fuzzy spatiotemporal RDF graph. Finally, the experimental results demonstrate the effectiveness of our approach which can significantly solve the inconsistency problem of fuzzy spatiotemporal RDF graphs.

Querying multi-source heterogeneous fuzzy spatiotemporal data

With the rapid development of the environmental, meteorological and marine data management, fuzzy spatiotemporal data has received considerable attention. Even though some achievements in querying aspect have been made, there are still some unsolved problems. Semantic and structural heterogeneity may exist among different data sources, which will lead to incomplete results. In addition, there are ambiguous query intentions and conditions when the user queries the data. This paper proposes a fuzzy spatiotemporal data semantic model. Based on this model, the RDF local semantic models are converted into a RDF global semantic model after mapping relational data and XML data to RDF local semantic models. The existing methods mainly convert relational data to RDF Schema directly. But our approach converts relational data to XML Schema and then converts it to RDF, which utilizes the semi-structured feature of XML schema to solve the structural heterogeneity between different data sources. The integration process enables us to perform global queries against different data sources. In the proposed query algorithms, the query conditions inputted are converted into exact queries before the results are returned. Finally, this paper has carried out extensive experiments, calculated the recall, precision and F-Score of the experimental results, and compared with other state-of-the-art query methods. It shows the importance of the data integration method and the effectiveness of the query method proposed in this paper.

Adaptive query relaxation and result categorization of fuzzy spatiotemporal data based on XML

With the rapid development of spatiotemporal information and its applications, querying spatiotemporal data has received considerable attention. Meanwhile, the imprecision and uncertainty of information cannot be ignored in many practical applications. Querying fuzzy spatiotemporal data have become one of the most important topics in academia and industry. Although there have been some achievements in querying aspect, the study about fuzzy spatiotemporal query relaxation is still few. In fact, query relaxation is necessary when the amount of query results is small or even empty, especially in the process of querying fuzzy spatiotemporal data. In this paper, we propose an adaptive query relaxation and result categorization approach for fuzzy spatiotemporal data based on XML, which is compatible with spatiotemporal features when spatiotemporal related queries are performed. The approach does not depend on any specific domain or user, it can adaptively relax the initial query requirements, and classify the results by user context preferences and data distribution after query relaxation. In order to locate the spatiotemporal data quickly and show the corresponding fuzziness apparently, we adopted XML to construct the fuzzy spatiotemporal model for query relaxation because XML data can be represented as a tree model which can flexibly arrange the spatiotemporal nodes at the specified position and mark the fuzziness of nodes on the path. In addition, after query relaxation, we present the results categorization algorithm to address the problem of information overload, and then return a navigation tree to the user. Finally, we launch a comprehensive set of experiments to demonstrate the effectiveness and efficiency of our proposed approach. Results of experiments demonstrate that our adaptive query relaxation and result categorization approach based on XML has higher recall and precision in spatiotemporal related query, and can capture the user’s needs and preferences effectively as well.

An integration approach of multi-source heterogeneous fuzzy spatiotemporal data based on RDF

With the growing importance of the fuzzy spatiotemporal data in information application, there is an increasing need for researching on the integration method of multi-source heterogeneous fuzzy spatiotemporal data. In this paper, we first propose a fuzzy spatiotemporal RDF graph model based on RDF (Resource Description Framework) that proposed by the World Wide Web Consortium (W3C) to represent data in triples (subject, predicate, object). Secondly, we analyze and classify the related heterogeneous problems of multi-source heterogeneous fuzzy spatiotemporal data, and use the fuzzy spatiotemporal RDF graph model to define the corresponding rules to solve these heterogeneous problems. In addition, based on the characteristics of RDF triples, we analyze the heterogeneous problem of multi-source heterogeneous fuzzy spatiotemporal data integration in RDF triples, and provide the integration methods FRDFG in this paper. Finally, we report our experiments results to validate our approach and show its significant superiority.

An Algebra for Fuzzy Spatiotemporal Data in XML

A formal algebra is essential for applying standard database-style query optimization to XML queries. We develop such algebra for manipulating fuzzy spatiotemporal XML data. We also introduce several formal characterizations of fuzzy spatiotemporal algebraic equivalences and study how XQuery expressions can be transformed into algebraic expressions. It shows that the algebra can lay a firm foundation for managing fuzzy spatiotemporal XML data.

Fuzzy Spatiotemporal Data Modeling Based on UML

With the wide application of spatiotemporal data, more and more data need to be modeled. Fuzziness is one of the important characteristics of spatiotemporal data, but most of the existing spatiotemporal data models are regarded as accurate data and most of the spatiotemporal data models are static. The purpose of this paper is to build a fuzzy spatiotemporal data model based on UML by expanding the standard modeling language UML. On this basis, the historical topological state, effective time, and transaction time are added to make the model dynamic, that is, the states of multiple times are combined together to form a timeline to represent the development process of a fuzzy spatiotemporal entity. Considering the fuzziness of data and the dynamic development of objects, the model can describe the fuzzy spatiotemporal objects better, and make the model dynamic. At the same time, the operation of the UML class diagram is added to make the model data exercisable and compared according to their own needs, which increases the practicability of the model. Finally, an example of land desertification in Alashan is given, to prove the practicability of the model constructed in this paper.

Transformation of fuzzy spatiotemporal data from XML to object-oriented database

The rapid development of the Internet promotes that XML is increasingly accepted as a medium for integrating and exchanging data. Meanwhile, object-oriented database with many excellent properties has been applied more and more widely. In particular, considering the need of processing the fuzzy spatiotemporal data existing in practical applications, we study the methodology of building fuzzy spatiotemporal data model and transforming fuzzy spatiotemporal data from XML to object-oriented database as well. To establish a suitable model, we devise a fuzzy spatiotemporal data model in XML to capture the semantics of fuzzy spatiotemporal features. In addition, we take the object-oriented schema that best describes the exciting fuzzy XML Schema and the characteristics of the XML tree structure into account to develop a series of rules to map spatiotemporal data from XML to object-oriented database. Such mapping rules could provide a significant consolidation of the interoperability of fuzzy spatiotemporal data from XML to object-oriented databases.

Transforming Fuzzy Spatiotemporal Data From Relational Databases to XML

On account of the poor shareability of fuzzy spatiotemporal data in Web while XML could contribute to information performance and information interaction flexibly, we study the methodology of modeling the fuzzy spatiotemporal data based on relational database and transforming fuzzy spatiotemporal data from relational database to XML. In this paper, we propose a kind of fuzzy spatiotemporal relational model and devise a temporal edge approach to transform fuzzy spatiotemporal relational data into XML documents, which is devoted to capturing the semantics of fuzzy spatiotemporal features, such as temporal feature, spatial feature, and fuzzy feature. The unique of this approach is that no schema information is required for transformation of fuzzy spatiotemporal data. Finally, the study would solve the challenge of both information share and information transfer between relational database and XML of fuzzy spatiotemporal data. Such approach of transformation would make a contribution to the interoperability of fuzzy spatiotemporal data between relational database and XML.

Reengineering Object-Oriented Fuzzy Spatiotemporal Data into XML

With the rapid development of the Internet, XML has become the defacto standard for integrating and exchanging data. Since more and more business data are stored in object-oriented database, we study the methodology of modeling fuzzy spatiotemporal data and transforming fuzzy spatiotemporal data from object-oriented databases to XML as well. In order to allow for better and platform independent sharing of fuzzy spatiotemporal data stored in an object-oriented format, we devise a fuzzy spatiotemporal data model in object-oriented database to capture the semantics of spatiotemporal features. In particular, XML schema best describes the existing fuzzy object-oriented schema, and we investigate the transforming rules of spatiotemporal data from fuzzy object-oriented database to XML. Furthermore, an instance demonstrates the validation of our approach. Such approach of transformation can provide a significant consolidation of the interoperability of fuzzy spatiotemporal data from object-oriented databases to XML.

Determining Topological Relations of Fuzzy Spatiotemporal Regions Over Time in XML

Determining topological relations is one of the most important operations on fuzzy spatiotemporal data, which has an important significance in reasoning. In order to determine topological relations, a considerable amount of approaches have been proposed. Those efforts are quite efficient for determining discrete topological relations. But for continuous determining topological relations, the previous approaches often suffer from insufficient extensions and high cost, which significantly decrease the performance. To overcome this limitation, in this paper, we model topological relations between fuzzy spatiotemporal regions over time in XML and propose an algorithm to identify topological relations. Our approach adopts a combination of superscript and subscript so that continuous topological relations can be represented as unique. More importantly, determining topological relations in XML can reduce execution time rather than a traditional database, since XML has structural advantages and can avoid complex extensions. Finally, we run experiments to validate our approach and show its significant superiority.

Fuzzy spatio-temporal data modeling based on XML schema

With the rapid development of Internet and Big data applications, massive time and space data need to be processed. In order to manage space and time data, the key point is to build a correct data model. There are a lot of fuzzy temporal and spatial information in the real world, and XML has been a useful technology for dealing with various information in the context of Web. In this paper, we first study the fuzzy spatio-temporal data tree by extending the XML Schema and then propose a fuzzy spatio-temporal data model based on XML. Finally, we use the meteorological data to illustrate the validity and usability of the model.

FSPTwigFast: Holistic twig query on fuzzy spatiotemporal XML data

With spatiotemporal applications increasing, a large amount of spatiotemporal data emerges. Because temporal and spatial attributes are often vague, research on fuzzy spatiotemporal data, especially querying fuzzy spatiotemporal data, has attracted a lot of attention. However, although fuzzy logic is incorporated in querying fuzzy spatiotemporal data and querying fuzzy data in XML, relatively little work has been carried out in querying fuzzy spatiotemporal data in XML. In this paper, we propose an algorithm, called FSPTwigFast, to match fuzzy spatiotemporal XML twig pattern. We represent fuzzy spatiotemporal data by adding temporal and spatial attributes associating with fuzziness in crisp data. We extend Dewey code to mark fuzzy spatiotemporal data for special process and determine structure relationship of fuzzy spatiotemporal nodes in XML documents. Our technique uses streams to store leaf nodes in XML document corresponding to leaf query nodes, which are filtered to delete unmatched nodes. After filtering, output lists are built for every matched leaf node. Finally, the experimental results demonstrate the performance advantages of our approach.

Consistencies of fuzzy spatiotemporal data in XML documents

Researches on spatiotemporal data based on XML has received increasing attention due to that XML has a lot of advantages such as extensibility and flexibility. Although XML has been employed to model and handle spatiotemporal data, relatively little work has been carried out to further investigate the consistencies of spatiotemporal data, especially fuzzy spatiotemporal data in XML documents. In this paper, we first propose a fuzzy spatiotemporal data model, and then present the structure of fuzzy spatiotemporal data in XML document. After studying consistency conditions for fuzzy spatiotemporal data in XML documents, we demonstrate how updating operations, inserting operations, and deleting operations effect on consistencies of fuzzy spatiotemporal data in XML documents. Furthermore, we propose algorithms for fixing these inconsistencies. After investigating several characteristics of the three primitive changing operations on the fuzzy spatiotemporal data model, the performances of inconsistency fixing time are evaluated.

Fixing inconsistencies of fuzzy spatiotemporal XML data

Fuzzy spatiotemporal data models have been used to support spatial and temporal knowledge representation and reasoning in the presence of fuzziness. In the meantime, XML is expected to become the next generation standard language for exchanging data over the Internet, which will become a trend to represent fuzzy spatiotemporal data based on XML. However, fuzzy spatiotemporal XML documents may contain inconsistencies violating predefined spatial and temporal constraints, which cause the data inconsistency problems. Although those consistency problems in XML documents have been widely studied, their studies only take the general data into account, and the studies on consistencies of fuzzy spatiotemporal data are still open issues. In this paper we put forward solutions to the problems of inconsistencies in fuzzy spatiotemporal XML documents. We also analyze inconsistent states which are named discontinuity overlap or cycle of the temporal labels of some incoming edges. Then, we put forward the corresponding approaches to checking and fixing fuzzy spatiotemporal XML documents according to the inconsistent states. Finally, the experimental results show that our proposed algorithms can fix inconsistencies of fuzzy spatiotemporal XML documents significantly.

Reengineering Fuzzy Spatiotemporal UML Data Model Into Fuzzy Spatiotemporal XML Model

Spatiotemporal information and application have received considerable attention. Spatiotemporal information is often imprecise or uncertain; therefore, the establishment of a reasonable and effective fuzzy spatiotemporal data model is vital. The traditional tool-based modeling method cannot meet the needs of fuzzy spatiotemporal data modeling. XML has become the standard of Web data representation and exchange. Based on the fuzzy set and probability theory, this paper analyzes the characteristics of fuzzy spatiotemporal data and establishes a fuzzy spatiotemporal XML data model. We present a fuzzy spatiotemporal UML data model and provide the rules for converting the fuzzy spatiotemporal UML data model to the fuzzy spatiotemporal XML model. We demonstrate our model and the conversion by applying them to a meteorological event.