• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.3
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• pp.12-36
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• 2023

Graph databases, which store different types of data and their relationships modeled as a graph, can be effective in managing and analyzing real estate spatial data linked by complex relationships. However, they are not widely used due to the limited spatial functionalities of graph databases. In this study, we propose a uniform grid-based real estate spatial data management approach using a graph database to respond to various real estate-related spatial questions. By analyzing the real estate community to identify relevant data and utilizing national point numbers as unit grids, we construct a graph schema that linking diverse real estate data, and create a test database. After building a test database, we tested basic topological relationships and spatial functions using the Jackpine benchmark, and further conducted query tests based on various scenarios to verify the appropriateness of the proposed method. The results show that the proposed method successfully executed 25 out of 29 spatial topological relationships and spatial functions, and achieved about 97% accuracy for the 25 functions and 15 scenarios. The significance of this study lies in proposing an efficient data integration method that can respond to real estate-related spatial questions, considering the limited spatial operation capabilities of graph databases. However, there are limitations such as the creation of incorrect spatial topological relationships due to the use of grid-based indexes and inefficiency of queries due to list comparisons, which need to be improved in follow-up studies.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.4
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• pp.231-239
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• 1987

Distribution system is one of large and complicated sytem, consisted of a great number of components. Therefore efficient operation based on precise analysis and computation methods is indispensable accommodating growing loads. This paper describes an optimal operation problem to relieve overload flow in radial distribution systems by using modified block model. The problem is formulated as a network problem of synthesizing the optimal spanning tree in a graph, branch and bound method is used for the optimization. Especially modified block model proposed in this paper is validated more practical than conventional model. These methods can be applied to two types of distribution system problems such as, 1) planning problem to check the capability of relieving overload at normal rating, 2) emergency operation problem to determine switching scheme for minimizing customer loads affected by a fault. Examples of application to these problems are discussed.

• The Transactions of the Korea Information Processing Society
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• v.5 no.9
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• pp.2435-2446
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• 1998

In this paper. We describe a dataflow model for efficient execution of a functional logic language and a method of translation a functional logic language into a dataflow graph. To explore parallelism and intelligent backtracking, we us model in which clause and function are represented as independent dataflow graph. The node denotes basic actions to be performed when the clause and function are executed. The dataflow mechanism allows an operation to be executed as soon as all its operands are available. Since the operations can never be executed earlier, a dataflow model is an excellent base for increasing execution speed. We did decrease a delay time with concurrent execution of dependency analysis and subgoal.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.79-92
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• 2020

As the number of systems increases and the network size increases, automated attack prediction systems are urgently needed to respond to cyber attacks. In this study, we developed four types of information gathering sensors for collecting asset and vulnerability information, and developed technology to automatically generate attack graphs and predict attack targets. To improve performance, the attack graph generation method is divided into the reachability calculation process and the vulnerability assignment process. It always keeps up to date by starting calculations whenever asset and vulnerability information changes. In order to improve the accuracy of the attack target prediction, the degree of asset risk and the degree of asset reference are reflected. We refer to CVSS(Common Vulnerability Scoring System) for asset risk, and Google's PageRank algorithm for asset reference. The results of attack target prediction is displayed on the web screen and CyCOP(Cyber Common Operation Picture) to help both analysts and decision makers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1774-1779
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• 2005

This paper propose the design method of the constructing the digital logic systems over galois fields using by the galois field decision diagram(GFDD) that is based on the graph theory. The proposed design method is as following. First of all, we discuss the mathematical properties of the galois fields and the basic properties of the graph theory. After we discuss the operational domain and the functional domain, we obtain the transformation matrixes, $\psi$GF(P)(1) and $\xi$GF(P)(1), in the case of one variable, that easily manipulate the relationship between two domains. And we extend above transformation matrixes to n-variable case, we obtain $\psi$GF(P)(1) and $\xi$GF(P)(1). We discuss the Reed-Muller expansion in order to obtain the digital switching functions of the P-valued single variable. And for the purpose of the extend above Reed-Muller expansion to more two variables, we describe the Kronecker product arithmetic operation.

• International Journal of Advanced Culture Technology
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• v.6 no.2
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• pp.117-122
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• 2018

As evidenced through rapidly growing digital repositories and web resources, automatic metadata generation is becoming ever more critical, especially considering the costly and complex operation of manual metadata creation. Also, automatic metadata generation is apt to consistent metadata application. In this sense, metadata quality and interoperability can be enhanced by utilizing a mechanism for automatic metadata generation. In this article, a mechanism of automatic metadata extraction called ExMETA is introduced in order to alleviate issues dealing with inconsistent metadata application and semantic interoperability across ever-growing digital collections. Conceptual graph, one of formal languages that represent the meanings of natural language sentences, is utilized for ExMETA as a mediation mechanism that enhances the metadata quality by disambiguating semantic ambiguities caused by isolation of a metadata element and its corresponding definition from the relevant context. Hence, automatic metadata generation by using ExMETA can be a good way of enhancing metadata quality and semantic interoperability.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.118-118
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• 1993

We consider a discrete event dynamic system called periodic job shop, where an identical mixture of items called minimal part set(MPS) is repetitively produced in the same processing order and the primary performance measure is the cycle time. The precedence relationships among events(starts of operations) are represented by a directed graph with rocurront otructure. When each operation starts as soon as all its preceding operations complete(called earliest starting), the occurrences of events are modeled in a linear system using a special algebra called minimax algebra. By investigating the eigenvalues and the eigenvectors, we develop conditions on the directed graph for which a stable steady state or a finite eigenvector exists. We demonstrate that each finite eigenvector, characterized as a finite linear combination of a class of eigenvalue, is the minimum among all the feasible schedules and an identical schedule pattern repeats every MPS. We develop an efficient algorithm to find a schedule among such schedules that minimizes a secondary performance measure related to work-in-process inventory. As a by-product of the linear system approach, we also propose a way of characterizing stable steady states of a class of discrete event dynamic systems.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.184-186
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• 2008

In this paper, the protective coordination studied in application of HTS cable in conductive system. The protective coordination analyzed to HTS cable using the PSCAD/EMTDC. HTS cable simulated to be appling SFCL or not to be. The result was showed to be protective coordination graph in HTS cable and OCR curve at the power system fault. This graph was proposed to be power operation standard at the HTS cable fault.

• Industrial Engineering and Management Systems
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• v.7 no.2
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• pp.84-92
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• 2008

Scheduling is one of the most important issues in the planning and operation of production systems. This paper investigates a general job shop scheduling problem with reentrant work flows and sequence dependent setup times. The disjunctive graph representation is used to capture the interactions between machines in job shop. Based on this representation, four two-phase heuristic procedures are proposed to obtain near optimal solutions for this problem. The obtained solutions in the first phase are substantially improved by reversing the direction of some critical disjunctive arcs of the graph in the second phase. A comparative study is conducted to examine the performance of these proposed algorithms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.267-270
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• 2001

A lot of efforts have been made to analyze the performance of the vehicle equipped with automatic transmission through simulation. It might be necessary to understand the different types of transmissions, i.e., different power flows, for different models. If there is a module that can be applied to different types of automatic transmission, it could be helpful to transmission-related engineers. This study has started up from this idea. The common bond graph has been obtained from several types of the automatic transmission. The overall generalized equations and kinematic constraint equations have been derived using virtual power sources on common bond graph. They are used to derive state equations and constraints. These equations have been applied as an application to the vehicle equipped with two simple planetary gear set type of Ravigneaux gear type automatic transmission. The state equation, kinematic constraints, and dynamic constraints have been derived in every gear and shift operation using overall generalized equations and kinematic constraint equations. Simulations for constraint speed running, standing-start running, rolling-start running, and LA-4 mode have been conducted to analyze the performance of the vehicle powertrain using GVPS(Generalized Vehicle Powertrain Simulation) program wit pull down menus.