• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4771-4787
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• 2019

Aimed at the disclosure risk of mobile terminal user's location privacy in location-based services, a location-privacy protection scheme based on similar trajectory substitution is proposed. On the basis of the anonymized identities of users and candidates who request LBS, this scheme adopts trajectory similarity function to select the candidate whose trajectory is the most similar to user's at certain time intervals, then the selected candidate substitutes user to send LBS request, so as to protect user's privacy like identity, query and trajectory. Security analyses prove that this scheme is able to guarantee such security features as anonymity, non-forgeability, resistance to continuous query tracing attack and wiretapping attack. And the results of simulation experiment demonstrate that this scheme remarkably improve the optimal candidate' trajectory similarity and selection efficiency.

• Bioinformatics and Biosystems
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• v.2 no.1
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• pp.7-11
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• 2007

Methods for making scoring matrix based on phylogenetic tree for all possible exchanges of one amino acid with another. PFMT(Phylogenetic focused Mutation Tendency) matrix is different BLOSUM62 and PAM160 which are the most used scoring matrixes. This matrix calculates possibility of substitution from common ancestor to high spices. PFMT matrix scores substitution frequency in COGs databases which contain 152 KOGs's dataset. PFMT matrix usefully is able to compare between query sequence and sequences of more higher species and show detailed substitution relation of 20 amino acids.

• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.554-569
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• 2005

In the semistructured distributed documents, it is very difficult to formalize and implement the query processing system due to the lack of structure and rule of the data. In order to precisely retrieve and process the heterogeneous semistructured documents, it is required to handle multiple mappings such as 1:1, 1:W and W:1 on an element simultaneously and to generate the schema from the distributed documents. In this paper, we have proposed an query processing algorithm for querying and answering on the heterogeneous semistructured data or documents over distributed systems and implemented with a metadata interface. The algorithm for generating local queries from the global query consists of mapping between g1oba1 and local nodes, data transformation according to the mapping types, path substitution, and resolving the heterogeneity among nodes on a global input query with metadata information. The mapping, transformation, and path substitution algorithms between the global schema and the local schemas have been implemented the metadata interface called DBXMI (for Distributed Documents XML Metadata Interface). The nodes with the same node name and different mapping or meanings is resolved by automatically extracting node identification information from the local schema automatically. The system uses Quilt as its XML query language. An experiment testing is reported over 3 different OEM model semistructured restaurant documents. The prototype system is developed under Windows system with Java and JavaCC compiler.

• Journal of Korea Multimedia Society
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• v.12 no.1
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• pp.1-15
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• 2009

This paper presents an assignment method of the multidimensional type inheritance indexes (MD-TIXs) to support the processing of XML queries in XML databases. MD-TIX uses a multidimensional index structure for efficiently supporting nested predicates that involve both nested element and type inheritance hierarchies. In this paper, we have analyzed the strategy of the query processing by using the MD-TIXs, and presented an assignment method of the MD-TIXs in the framework of complex queries, containing conjunctions of nested predicates, each one involving an Xpath having target types or domain types substitution. We first consider MD-TIX operations caused by updating of XML data-bases, and the use of the MD-TIXs in the case of a query containing a single nested predicate. And then, we consider the assignments of the MD-TIXs in the framework of more general queries containing nested predicates over overlapping paths that have common subpaths.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.859-876
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• 2004

This paper presents optimal configurations of multidimensional path indexes (MPIs) for the efficient execution of object-oriented queries in object databases. MPI uses a multidimensional index structure for efficiently supporting nested predicates that involve both nested attribute and class hierarchies, which are not supported by the nested attribute index using one-dimensional index structure such as $B^+$-tree. In this paper, we have analyzed the MPIs in the framework of complex queries, containing conjunctions of nested predicates, each one involving a path expression having target classes and domain classes substitution. First of all, we have considered MPI operations caused by updating of object databases, and the use of the MPI in the case of a query containing a single nested predicate. And then, we have considered the use of the MPIs in the framework of more general queries containing nested predicates over both overlapping and non-overlapping paths. The former are paths having common subpaths, while the latter have no common subpaths.