• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.123-130
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• 2001

As the growth of database volume, it has required a need and an opportunity of data analysis and extracting knowledge from database. Data mining method is the representative example. The size of most minable data set is huge, and stored in a database. To implement effective mining function, we must extract minable data set to be analyzed from existing relational database, and it must be managed with its generalized information. In this paper, the new mining operator is defined in a similar manner to the existing SQL operators and SQL is extended to extract data subset from relations and to generalize it using domain-oriented method. The background knowledge includes attribute values, which will be mind and generalized information, and it is managed as the same structure with a relation in relational database. These functions are implemented by defining some SQL - like operators and aggregated functions, and we describe the expressive powers of these new operators and functions through examples.

• Communications of the Korean Mathematical Society
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• v.29 no.1
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• pp.37-50
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• 2014

Using variational methods, we prove some results on the nonexistence and multiplicity of weak solutions for a class of semilinear elliptic systems of two equations involving Grushin type operators with sign-changing nonlinearities. We also shows that the similar results can be obtained for systems of m equations, where m is arbitrary.

• Communications of the Korean Mathematical Society
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• v.32 no.3
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• pp.677-688
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• 2017

The composition of Jacobi type finite classes of the classical orthogonal polynomials with two generalized Riemann-Liouville fractional derivatives are considered. The outcomes are expressed in terms of generalized Wright function or generalized hypergeometric function. Similar composition formulas are also obtained by considering the generalized Riemann-Liouville and $Erd{\acute{e}}yi-Kober$ fractional integral operators.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.132-135
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• 1999

In this work, two approaches were proposed for the recognition of partial discharge patterns. The first approach was neural network with backpropagation algorithm, and the second approach was angle calculation between two operator vectors. PD signal were detected using three electrode systems; IEC(b), needle-plane and CIGRE method II electrode system. Both of neural network and angle comparison method showed good recognition performance for the patte군 similar to the trained patterns. And the number of operators to be used had a great influence on the recognition performance to the untrained patterns.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.342-348
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• 2009

Many rail operators have developed ticketing systems for the use of rail service and the increase of operation revenue by AIM, E-ticket and mobile tickets. Also they have operated rail pass for rail revenue by foreign tourists. Russian railways (RZD) has similar rail systems with CIS countries and sometimes same tickets. A few years ago, RZD introduced and operated E-ticketing system for the increase of passenger's convenience and operation revenue, and CIS countries have adopted and widely used this system. This study will introduce the revenue business by E-ticketing system of RZD, and forecast Russian railroad business in the future.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.623-626
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• 2000

The purpose of this paper is to find an efficient solution for multiple constant multiplication (MCM) problem. Since the circuit structure can be represented as a directed acyclic graph, evolutionary computing is considered as an effective tool for optimization of circuit synthesis. In this paper, we propose a stack type operator as a chromosome element to synthesize a directed acyclic graph efficiently. This type of chromosome can represent a graph structure with a set of simple symbols and so we can employ the similar method to a conventional GA.

• Journal of Environmental Impact Assessment
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• v.14 no.6
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• pp.387-402
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• 2005

In this study, we tried to predict the change of future land-cover and relationships between land-cover change and geo-spatial information in the Gongju area by using fuzzy logic operation. Quantitative evaluation of prediction models was carried out using a prediction rate curve using. Based on the analysis of correlations between the geo-spatial information and land-cover change, the class with the highest correlation was extracted. Fuzzy operations were used to predict land-cover change and determine the land-cover prediction maps that were the most suitable. It was predicted that in urban areas, the urban expansion of old and new towns would occur centering on the Gem-river, and that urbanization of areas along the interchange and national roads would also expand. Among agricultural areas, areas adjacent to national roads connected to small tributaries of the Gem-river and neighboring areas would likely experience changes. Most of the forest areas are located in southeast and from this result we can guess why the wide chestnut-tree cultivation complex is located in these areas and the possibility of forest damage is very high. As a result of validation using the prediction rate curve, it was indicated that among fuzzy operators, the maximum fuzzy operator was the most suitable for analyzing land-cover change in urban and agricultural areas. Other fuzzy operators resulted in the similar prediction capabilities. However, in the prediction rate curve of integrated models for land-cover prediction in the forest areas, most fuzzy operators resulted in poorer prediction capabilities. Thus, it is necessary to apply new thematic maps or prediction models in connection with the effective prediction of changes in the forest areas.

• Journal of Korean Society of Rural Planning
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• v.20 no.1
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• pp.63-76
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• 2014

The purpose of this study is to identify effect in how urban garden is run by different operators in Korea, and consequently how it determines the level of community formation among urban garden users. Based on this analysis, the study is intended to present some points as to how to better manage urban garden. The operators are divided into three types: public, public-private partnership and private. The study interviewed each operating entity and surveyed garden users to gauge the extent to which communities are developed. After the ANOVA analysis and Scheffe post-hoc analysis, it was found that the levels of community formation among users of public and public-private partnership urban gardens were similar (so can be grouped together), whereas that of private urban garden users was higher (separated as another group). However, this study found no meaningful differences in the level of community formation among all types of urban garden in a local community. Some key suggestions are made as a result. First, as for the public and public-private partnership types of urban garden, it is necessary to foster leaders to build a community. Next, it is worth noting the potential of public-private partnership in realizing community revival through urban garden. The last suggestion is that, generally, the urban garden has only little influence on community formation in a local area so far, thus more practical consideration needs to be given to enhance the role of urban garden in a local community.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.8-15
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• 2012

The GO-FLOW methodology is capable of assessing system reliability. It models the system into a GO-FLOW chart with signal lines and operators and assesses the reliability of system by assessing the GO-FLOW chart sequential. But, as it models one component of system into several operators, the GO-FLOW chart which is different from the system flow diagram be modeled. Also, as it models the real operation time into "time point", it is hard to assess the reliability change according to the real operation time. Therefore, in this paper, the new GO-FLOW methodology which use the function(success/failure) of system components has been developed. It can assess the successful operating probability of system, regardless of the operating status of components. As it models one component of system into one operator, the GO-FLOW chart which is similar the system flow diagram can be modeled. Also, it is able to easily assess the successful probability of system according to the real operation time using the time in the operators.

• Korean Journal of Remote Sensing
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• v.21 no.2
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• pp.145-162
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• 2005

To improve the accuracy of land-cover discrimination in SAB data classification, this paper presents a methodology that includes feature extraction and fusion steps with multi-temporal SAR data. Three features including average backscattering coefficient, temporal variability and coherence are extracted from multi-temporal SAR data by considering the temporal behaviors of backscattering characteristics of SAR sensors. Dempster-Shafer theory of evidence(D-S theory) and fuzzy logic are applied to effectively integrate those features. Especially, a feature-driven heuristic approach to mass function assignment in D-S theory is applied and various fuzzy combination operators are tested in fuzzy logic fusion. As experimental results on a multi-temporal Radarsat-1 data set, the features considered in this paper could provide complementary information and thus effectively discriminated water, paddy and urban areas. However, it was difficult to discriminate forest and dry fields. From an information fusion methodological point of view, the D-S theory and fuzzy combination operators except the fuzzy Max and Algebraic Sum operators showed similar land-cover accuracy statistics.