• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.19-27
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• 2011

Access control that has been previously performed mainly on safety, and thus not much effort has been done to consider access control in terms of efficiency. This paper proposes a method for an efficient and secure query processing of XML data streams, such as a personal digital assistant and a portable terminal, at the client side with limited resources. Specifically, this paper proposes an access control processing that possesses a small overhead for attaining a secure result with limited memory and a method to enhance the performance, finding the parts capable of optimizing each processing step for offsetting the overhead caused by the addition of access control processing. The superiority of the new method is analyzed through an experiments.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.8-15
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• 2003

Recently various of information suppliers provide information via WWW so the necessary of search engine grows larger. However the efficiency of most search engines is low comparatively because of using simple pattern match technique between user's query and web document. A specialized search engine returns the specialized information depend on each user's search goal. It is trend to develop specialized search engines in many countries. However, most such engines don't satisfy the user's needs. This paper proposes the specialized search engine for ocean information that uses user's query related with ocean and the association rules in web data mining can prove relation between web documents. So this search engine improved the recall of data and the precision in existent search method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.5171-5189
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• 2016

With the popularity of cloud computing, many data owners outsource their graph data to the cloud for cost savings. The cloud server is not fully trusted and always wants to learn the owners' contents. To protect the information hiding, the graph data have to be encrypted before outsourcing to the cloud. The adjacent vertex search is a very common operation, many other operations can be built based on the adjacent vertex search. A boolean adjacent vertex search is an important basic operation, a query user can get the boolean search results. Due to the graph data being encrypted on the cloud server, a boolean adjacent vertex search is a quite difficult task. In this paper, we propose a solution to perform the boolean adjacent vertex search over encrypted graph data in cloud computing (BASG), which maintains the query tokens and search results privacy. We use the Gram-Schmidt algorithm and achieve the boolean expression search in our paper. We formally analyze the security of our scheme, and the query user can handily get the boolean search results by this scheme. The experiment results with a real graph data set demonstrate the efficiency of our scheme.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.25-36
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• 2009

In this paper, we propose an efficient data management scheme for path queries and containment queries which are occurred frequently. The proposed data management scheme considers a change of the containment of products during a transport and supports a path of changed products by representing a path of various containments. Also, the compression utilizing the structure of supply chain reduces the stored data volumes. As a result, our method outperforms the existing methods in terms of storage efficiency and query processing time.

• Journal of Integrative Natural Science
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• v.2 no.4
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• pp.243-251
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• 2009

This paper surveys some researches to accomplish on bioinformatics. These researches wish to propose a database architecture combining a general view of bioinformatics data as a graph of data objects and data relationships, with the efficiency and robustness of data management and query provided by indexing and generic programming techniques. Here, these invert the role of the index, and make it a first-class citizen in the query language. It is possible to do this in a structured way, allowing users to mention indexes explicitly without yielding to a procedural query model, by converting functional relations into explicit functions. In the limit, the database becomes a graph, in which the edges are these indexes. Function composition can be specified either explicitly or implicitly as path queries. The net effect of the inversion is to convert the database into a hyperdatabase: a database of databases, connected by indexes or functions. The inversion approach was motivated by their work in biological databases, for which hyperdatabases are a good model. The need for a good model has slowed progress in bioinformatics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.9
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• pp.2717-2738
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• 2024

Cloud computing has extensively grown in recent years. A large amount of data is stored in cloud servers. To ensure confidentiality, these data is often encrypted and then stored in cloud servers. However, encryption makes range queries difficult to perform. To solve this issue, we present a scheme that facilitates fast range queries on encrypted multi-dimensional data in scenarios involving multiple users. In our scheme, we construct a tree index on encrypted multi-dimensional data, and each node is linked to a secure enhanced multi-dimensional range (MDR). To support efficient range query on the tree index, we adopt bloom filter technique. Additionally, users' privileges are designed in a one-way calculation manner to support that different users can only perform range queries within their own privileges. Finally, we conduct extensive experiments which show the efficiency of our scheme, and also conduct a thorough analysis of its security.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.54-62
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• 2010

Semantic Web programming is such an immature area that it is yet based on API calls, and does not provide high productivity in compiler time and sufficient efficiency in runtime. To get over this limitation, some efforts have been devoted on dedicated programming languages for Semantic Web. In this paper, we introduce a sophisticated cashing technique to enhance the runtime efficiency of RDF (Resource Description Framework) processing programs with SPARQL queries. We use static program analysis on those programs to determine what to be cashed, so as to decrease the cash miss ratio. Our method is implemented on programs in 'Jey' language, which is one of the programming languages devised for RDF data processing.

• Journal of the Korean Society for Library and Information Science
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• v.6
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• pp.87-103
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• 1979

Information storage and retrieval is a part of general communication process. In the Shannon's information theory, information contained in a message is a measure of -uncertainty about information source and the amount of information is measured by entropy. Indexing is a process of reducing entropy of information source since document collection is divided into many smaller groups according to the subjects documents deal with. Significant concepts contained in every document are mapped into the set of all sets of index terms. Thus index itself is formed by paired sets of index terms and documents. Without indexing the entropy of document collection consisting of N documents is $log_2\;N$, whereas the average entropy of smaller groups $(W_1,\;W_2,...W_m)$ is as small $(as\;(\sum\limits^m_{i=1}\;H(W_i))/m$. Retrieval efficiency is a measure of information system's performance, which is largely affected by goodness of index. If all and only documents evaluated relevant to user's query can be retrieved, the information system is said $100\%$ efficient. Document file W may be potentially classified into two sets of relevant documents and non-relevant documents to a specific query. After retrieval, the document file W' is reclassified into four sets of relevant-retrieved, relevant-not retrieved, non-relevant-retrieved and non-relevant-not retrieved. It is shown in the paper that the difference in two entropies of document file Wand document file W' is a proper measure of retrieval efficiency.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.9-16
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• 2002

Join operation exert a great effect on the performance of system in temporal database as in the relational database. Especially, as for the temporal join, the optimization of interval partition decides the performance of query processing. In this paper, to improve the efficiency of parallel join query in temporal database. I proposed Minimum Interval Partition(MIP) scheme that time interval partitioning. The validity of this MIP algorithm that decides minimum breakpoint of the partition is proved by example scenario and I confirmed improved efficiency as compared with existing partition algorithm.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.673-684
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• 2004

As the wireless mobile communication is being widespread, mobile technologies will have important roles in the communication with the explosive growth of demanding for wireless portable devices. Among the mobile technologies, a great deal of interest has been taken in mobile ad hoc network (MANET), which is a collection of wireless mobile nodes forming a temporary network without the aid of stationary infrastructure in recent. Furthermore, considering characteristic of ad hoc networks, the design of efficient routing protocols is an important issue. In recent years, on-demand protocols among routing protocols have noticed because of the low routing overhead. However, on-demand protocols suffer from production of the enormous query Packets by broadcasting in order to setup routes, that is, a flooding scheme. The flooding scheme is very costly and results in serious problem, which we refer as the broadcast storm problem. In this paper, we propose a Dynamic Adaptation Query flooding Using Neighbor Topology (NT-DAQ) scheme, in order to resolve the broadcast storm Problem. When a route discovery is in progress, each mobile node decides on the basis of neighbor topology information whether discovery process participates or not. Therefore, our proposed scheme enables to improve network performance in which minimize the number of query rackets. We evaluate the efficiency of our proposed scheme through simulation.