• Journal of KIISE
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• v.42 no.11
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• pp.1410-1422
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• 2015

In order to design a system, software developers use an object model such as the UML class diagram. Object-Relational Transformation Methodology (ORTM) is a methodology to transform the relationships that are expressed in the object model into relational database tables, and it is applied for the implementation of the designed system. Previous ORTM studies have suggested a number of transformation methods to represent one relationship. However, there is an implementation problem that is difficult to apply because the usage criteria for each transformation method do not exist. Therefore, this paper proposes a binary decision diagram-based modeling rule for each relationship. Hence, we define the conditions for distinguishing the transformation methods. By measuring the query execution time, we also evaluate the modeling rules that are required for the verification. After evaluation, we re-define the final modeling rules which are represented by propositional logic, and show that our proposed modeling rules are useful for the implementation of the designed system through a case study.

• Journal of KIISE
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• v.43 no.2
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• pp.237-245
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• 2016

In this paper we introduce a novel database research area called science of databases (SoDB) and carry out a comprehensive analysis of its case studies. SoDB aims to better understand interesting phenomena observed across multiple database management systems (DBMSes). While mathematical and engineering work in the database field has been dominant, less attention has been given to scientific approaches through which DBMSes can be better understood. Scientific investigations can lead to better engineered designs through deeper understanding of query optimizers and transaction processing. The SoDB research has investigated several interesting phenomena observed across different DBMSes and provided several engineering implications based on our uncovered results. In this paper we introduce a novel scientific, empirical methodology and describe the research infrastructure to enable the methodology. We then review each of a selected group of phenomena studied and present an identified structural causal model associated with each phenomenon. We also conduct a comprehensive analysis on the case studies. Finally, we suggest future directions to expand the SoDB research.

• Journal of Digital Contents Society
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• v.10 no.1
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• pp.129-145
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• 2009

As the secure distribution and sharing of information over the World Wide Web becomes increasingly important, the needs for flexible and efficient support of access control systems naturally arise. Since the eXtensible Markup Language (XML) is emerging as the de-facto standard format of the Internet era for storing and exchanging information, there have been recently, many proposals to extend the XML model to incorporate security aspects. To the lesser or greater extent, however, such proposals neglect the fact that the data for XML documents will most likely reside in relational databases, and consequently do not utilize various security models proposed for and implemented in relational databases. In this paper, we take a rather different approach. We explore how to support security models for XML documents by leveraging on techniques developed for relational databases considering object perspective. More specifically, in our approach, (1) Users make XML queries against the given XML view/schema, (2) Access controls for XML data are specified in the relational database, (3) Data are stored in relational databases, (4) Security check and query evaluation are also done in relational databases, and (5) Controlling access control is executed considering XML tree levels

• Journal of Digital Convergence
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• v.11 no.3
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• pp.407-413
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• 2013

For Ubiquitous service, there are some method researched. To IT convergence study tourism the convergence of IT and tourism in recent years has emerged as a discipline in the future. Tourist information is information about tourism products as tourists tourism decision-making needed to say. Information presented information anytime, anywhere, using a contact-type media, mobile and efficient tourist information content and generate content using Smart App store to the database is needed. This paper, by taking advantage of the Smart App Places to generate content and Smart Things to query, modify, search, tourism information, tourism policy and tourists can be analyzed, and the average inclination and these efficient tourism information content and that can be utilizedmodels are proposed. This u-Smart is a tourist information system. Build the biggest advantages of the meta-meta-model in real time by utilizing Smart App disposition of existing tourism information and tourist and tourism rating database. Helps to generate patterned by digital tourism policy tourism information content.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.6
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• pp.643-648
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• 2003

In order to provide efficient retrieving results for user query on the web environment, the various searching algorithms have developed and considered user's preference and convenience. However, the searching algorithms are developed on the horizontal and non hierarchical web environment in general and could not apply to the complex hierarchical and functional web environments such like the enterprise network. In this paper, we purpose the multi-agent based web mining system which can provide the efficient mining results to the user on the special web environment. For doing this, we suggest the network model with the hierarchical web environment and model the multi agent based web mining system which has four corporation agents and fourteen process modules. Then, we explain the detailed functions of each agent considered the hierarchical environment according to the module. Especially, we purpose the new merging agent and improved ranking algorithm by using the graph theory.

• Korean Journal of Computational Design and Engineering
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• v.19 no.4
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• pp.390-401
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• 2014

ISO 15926 is an international standard for integration of lifecycle data for process plants including oil and gas facilities. From the viewpoint of information modeling, ISO 15926 Parts 2 provides the general data model that is designed to be used in conjunction with reference data. Reference data are standard instances that represent classes, objects, properties, and templates common to a number of users, process plants, or both. ISO 15926 Parts 4 and 7 provide the initial set of classes, objects, properties and the initial set of templates, respectively. User-defined reference data specific to companies or organizations are defined by inheriting from the initial reference data and the initial set of templates. In order to support the extension of reference data and templates, an editor that provides creation, deletion and modification functions of user-defined reference data is needed. In this study, an editor for reference data based on ISO 15926 was developed. Sample reference data were encoded in OWL (web ontology language) according to the specification of ISO 15926 Part 8. iRINGTools and dot15926Editor were benchmarked for the design of GUI (graphical user interface). Reference data search, creation, modification, and deletion functions were implemented with XML (extensible markup language) DOM (document object model), and SPARQL (SPARQL protocol and RDF query language).

• The Transactions of the Korea Information Processing Society
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• v.1 no.3
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• pp.299-310
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• 1994

Re-engineering tools can substantially increase software maintenance productivity and the quality of maintenance work. Re-engineering usually involves changing the form(e.g.changining objects names and definitions, restructuring process logic) of a program. In this paper, we describe the design and implementation of InMaC＋＋ that is a software tool oriented towards maintenance of C＋＋ object oriented programs. With InMaC＋＋, programms can be displayed and edited in two forms : as the code and as the diagram InMaC＋＋ also contains transformations in both directions, i,e. from code to diagram and from diagram to skeletons of code. Hence, it is suitable for re-engineering and maintenance of existing code. Specially designed browsers implement the graphical interface. InMaC＋＋ contains a database that is based on a simple but effective data model of InMaC＋＋ programs. The model contains only four object classes and three relations, which makes the tool small, and easy to implement and use. A simple query language allows browsing through the database.

• Journal of Communications and Networks
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• v.11 no.4
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• pp.337-349
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• 2009

In this paper, we introduce a novel mobility model for mobile sinks in which the sinks move towards randomly distributed destinations, where each destination is associated with a mission. The novel mobility model is termed the random mobility with destinations. There have been many studies on mobile sinks; however, they merely support two extreme cases of sink mobility. The first case features the most common and general mobility, with the sinks moving randomly, unpredictably, and inartificially. The other case takes into account mobility only along predefined or determined paths such that the sinks can gather data from sensor nodes with minimum overhead. Unfortunately, these studies for the common mobility and predefined path mobility might not suit for supporting the random mobility with destinations. In order to support random mobility with destination, we propose a new protocol, in which the source nodes send their data to the next movement path of a mobile sink. To implement the proposed protocol, we first present a mechanism for predicting the next movement path of a mobile sink based on its previous movement path. With the information about predicted movement path included in a query packet, we further present a mechanism that source nodes send energy-efficiently their data along the next movement path before arriving of the mobile sink. Last, we present mechanisms for compensating the difference between the predicted movement path and the real movement path and for relaying the delayed data after arriving of the mobile sink on the next movement path, respectively. Simulation results show that the proposed protocol achieves better performance than the existing protocols.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.430-448
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• 2001

In navigation system, a primary task is to compute the minimum cost route from the current location to the destination. One of major problems for navigation systems is that a significant amount of computation time is required when the digital road map is large. Since navigation systems are real time systems, it is critical that the path be computed while satisfying a time constraint. In this paper, we have developed a HiTi(Hierarchical MulTi) graph model for hierarchically structuring large digital road maps to speedup the minimum cost path computation. We propose a new shortest path algorithm named SPAH, which utilizes HiTi graph model of a digital road map for its computation. We prove that the shortest path computed by SPAH is the optimal. Our performance analysis of SPAH also showed that it significantly reduces the computation time over exiting methods. We present an in-depth experimental analysis of HiTi graph method by comparing it with other similar works.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.347-356
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• 2009

In an RFID search protocol, a reader uses designated query to determine whether a specific tag is in the vicinity of the reader. This fundamental difference makes search protocol more vulnerable to replay attacks than authentication protocols. Due to this, techniques used in existing RFID authentication protocols may not be suitable for RFID search protocols. In this paper, we propose two RFID search protocols, one based on static ID and the other based on dynamic ID, which use counter to prevent replay attacks. Moreover, we propose a security model for RFID search protocols that includes forward/backward traceability, de-synchronization and forgery attack. Based on this model, we analyze security of our protocols and related works.