The research on Temporal Databases (TDB) has been a hot topic for quite along time, but few implementations have been reported. The authors have developeda prototroe of temporal DBMS in DOS/Windows envirorunent, calle...The research on Temporal Databases (TDB) has been a hot topic for quite along time, but few implementations have been reported. The authors have developeda prototroe of temporal DBMS in DOS/Windows envirorunent, calledHBase. This paper discusses its temporal structure, temporal syntax and semanics,as well as the special techniques used in the Anplementation of HBase.展开更多
Purpose-Time modeling is a crucial feature in many application domains.However,temporal information often is not crisp,but is subjective and fuzzy.The purpose of this paper is to address the issue related to the model...Purpose-Time modeling is a crucial feature in many application domains.However,temporal information often is not crisp,but is subjective and fuzzy.The purpose of this paper is to address the issue related to the modeling and handling of imperfection inherent to both temporal relations and intervals.Design/methodology/approach-On the one hand,fuzzy extensions of Allen temporal relations are investigated and,on the other hand,extended temporal relations to define the positions of two fuzzy time intervals are introduced.Then,a database system,called Fuzzy Temporal Information Management and Exploitation(Fuzz-TIME),is developed for the purpose of processing fuzzy temporal queries.Findings-To evaluate the proposal,the authors have implemented a Fuzz-TIME system and created a fuzzy historical database for the querying purpose.Some demonstrative scenarios from history domain are proposed and discussed.Research limitations/implications-The authors have conducted some experiments on archaeological data to show the effectiveness of the Fuzz-TIME system.However,thorough experiments on large-scale databases are highly desirable to show the behavior of the tool with respect to the performance and time execution criteria.Practical implications-The tool developed(Fuzz-TIME)can have many practical applications where time information has to be dealt with.In particular,in several real-world applications like history,medicine,criminal and financial domains,where time is often perceived or expressed in an imprecise/fuzzy manner.Social implications-The social implications of this work can be expected,more particularly,in two domains:in the museum to manage,exploit and analysis the piece of information related to archives and historic data;and in the hospitals/medical organizations to deal with time information inherent to data about patients and diseases.Originality/value-This paper presents the design and characterization of a novel and intelligent database system to process and manage the imperfection inherent to both temporal relations and intervals.展开更多
The task of selecting the most appropriate method for indexing the data according to application requires a careful comparison study of indices of interests. In particular, we consider object movements by tracing thei...The task of selecting the most appropriate method for indexing the data according to application requires a careful comparison study of indices of interests. In particular, we consider object movements by tracing their trajectories within a predefined road network. MV3DR-tree and 3DR-tree constitute our first group indexing the objects moving in free movement scenarios. Besides, Mapping and MON-tree are the second group indexing the locations of objects moving over a network of road. Those access methods mainly organize a group of R-tree in order to index the underlying road network and the object movements. Our goal in this study is to evaluate existing proposals under fair circumstances with respect to storage consumption and spatio-temporal query execution performance. In our comparisons, we discuss the structure＇s sensibility to query＇s spatial and/or temporal extent as well as the tradeoff arising between two groups in terms of reliability and disk access performance. We believe that revealing the vulnerabilities of the selected structures, especially Mapping and MON-tree motivates us to design more robust organizations.展开更多
文摘The research on Temporal Databases (TDB) has been a hot topic for quite along time, but few implementations have been reported. The authors have developeda prototroe of temporal DBMS in DOS/Windows envirorunent, calledHBase. This paper discusses its temporal structure, temporal syntax and semanics,as well as the special techniques used in the Anplementation of HBase.
文摘Purpose-Time modeling is a crucial feature in many application domains.However,temporal information often is not crisp,but is subjective and fuzzy.The purpose of this paper is to address the issue related to the modeling and handling of imperfection inherent to both temporal relations and intervals.Design/methodology/approach-On the one hand,fuzzy extensions of Allen temporal relations are investigated and,on the other hand,extended temporal relations to define the positions of two fuzzy time intervals are introduced.Then,a database system,called Fuzzy Temporal Information Management and Exploitation(Fuzz-TIME),is developed for the purpose of processing fuzzy temporal queries.Findings-To evaluate the proposal,the authors have implemented a Fuzz-TIME system and created a fuzzy historical database for the querying purpose.Some demonstrative scenarios from history domain are proposed and discussed.Research limitations/implications-The authors have conducted some experiments on archaeological data to show the effectiveness of the Fuzz-TIME system.However,thorough experiments on large-scale databases are highly desirable to show the behavior of the tool with respect to the performance and time execution criteria.Practical implications-The tool developed(Fuzz-TIME)can have many practical applications where time information has to be dealt with.In particular,in several real-world applications like history,medicine,criminal and financial domains,where time is often perceived or expressed in an imprecise/fuzzy manner.Social implications-The social implications of this work can be expected,more particularly,in two domains:in the museum to manage,exploit and analysis the piece of information related to archives and historic data;and in the hospitals/medical organizations to deal with time information inherent to data about patients and diseases.Originality/value-This paper presents the design and characterization of a novel and intelligent database system to process and manage the imperfection inherent to both temporal relations and intervals.
文摘The task of selecting the most appropriate method for indexing the data according to application requires a careful comparison study of indices of interests. In particular, we consider object movements by tracing their trajectories within a predefined road network. MV3DR-tree and 3DR-tree constitute our first group indexing the objects moving in free movement scenarios. Besides, Mapping and MON-tree are the second group indexing the locations of objects moving over a network of road. Those access methods mainly organize a group of R-tree in order to index the underlying road network and the object movements. Our goal in this study is to evaluate existing proposals under fair circumstances with respect to storage consumption and spatio-temporal query execution performance. In our comparisons, we discuss the structure＇s sensibility to query＇s spatial and/or temporal extent as well as the tradeoff arising between two groups in terms of reliability and disk access performance. We believe that revealing the vulnerabilities of the selected structures, especially Mapping and MON-tree motivates us to design more robust organizations.
