• International Journal of Korean Welding Society
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• v.2 no.2
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• pp.47-50
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• 2002

Because of the environmental problems, automotive companies are trying to reduce the weight of car body. Therefore, TRIP(TRansformation Induced Plasticity) steels, which have high strength and ductility have been developed. Welding process is a complex process; therefore deciding the optimal welding conditions on the basis of experimental data is an effective method. However, trial-and-error method to decide the optimal conditions requires too many experiments. To overcome these problems, response surface methodology was used. Response surface methodology is a collection of mathematical and statistical techniques that are used in the modeling and analysis of problems in which a response of interest is influenced by several variables and the objective is to optimize this response. This method was applied to the resistance spot welding process of the TRIP steel to optimize the welding parameters.

• Journal of the Korea Society for Simulation
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• v.22 no.4
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• pp.67-82
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• 2013

This paper presents multi-fidelity modeling and simulation (M&S) methodology to enhance simulation performance of engineering-level defense models. In this approach, a set of models with varying degrees of fidelity is exercised to reduce computational expense maintaining a similar level of system effectiveness. For multi-fidelity M&S principles, this paper defines model fidelity from two perspectives (i.e., model behavior and execution), and suggests the Fidelity Change Point (FCP) to specify the fidelity conversion. With these concepts, this paper centers on three ideas: 1) two models' structure which are the Behavioral-Fidelity Interchangeable Model (B-FIM) and the Executional-Fidelity Interchangeable Model (E-FIM), 2) modeling formalism, and 3) a simulation algorithm to support them. From an abstract case study regarding a target tracking scenario with the utilization of the proposed method, we can gain interesting experimental results regarding the enhancement of simulation performance. Finally, we expect that this work will serve various M&S-based analysis areas for enhancing simulation performance.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.325-330
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• 2016

The second phase of low- and intermediate-level waste (LILW) disposal facility is under planned on the sedimentary rock in unsaturated zone. In this study, we created two meshes which were a matrix continuum mesh and a fracture continuum mesh to carry out 2 dimensional numerical modeling for groundwater flow in the unsaturated zone containing fractures focused on the second phase of LILW disposal facility. Two continuum meshes were developed using MINC in meshmaker module of TOUGH2 code. A fracture continuum mesh was included the k-field distribution of the permeability derived from the Discrete Fractured Network (DFN) modeling. To apply the unsaturated zone for the modeling, the gridding steps to generate mesh were developed. Each step to generate a mesh consisted of definition of materials, setting the initial conditions and creating grids using MINC. The methodology development of meshes in this study will be applied for more precise modeling of groundwater flow and mass transport.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.87-96
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• 2007

In this paper a methodology of identifying individual pipes according to the internal and external characteristics of pipe is developed, and the methodology is applied to a case study water distribution pipe break database. Using the newly defined individual pipes the hazard rates of the cast iron 6 inch pipes are modeled by implementing the proportional hazards modeling approach for consecutive pipe failures. The covariates to be considered in the modeling procedures are selected by considering the general availability of the data and the practical applicability of the modeling results. The individual cast iron 6 inch pipes are categorized into seven ordered survival time groups according to the total number of breaks recorded in a pipe to construct distinct proportional hazard model (PHM) for each survival time group (STG). The modeling results show that all of the PHMs have the hazard rate forms of the Weibull distribution. In addition, the estimated baseline survivor functions show that the survival probabilities of the STGs generally decrease as the number of break increases. It is found that STG I has an increasing hazard rate whereas the other STGs have decreasing hazard rates. Regarding the first failure the hazard ratio of spun-rigid and spun-flex cast iron pipes to pit cast iron pipes is estimated as 1.8 and 6.3, respectively. For the second or more failures the relative effects of pipe material/joint type on failure were not conclusive. The degree of land development affected pipe failure for STGs I, II, and V, and the average hazard ratio was estimated as 1.8. The effects of length on failure decreased as more breaks occur and the population in a GRID affected the hazard rate of the first pipe failure.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.77-84
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• 2016

This paper proposes a methodology for creating a function based reliability prediction model. Although, there are various works for reliability prediction, one of the features of their research is that the research is based on hardware-centered reliability prediction. Reliability is often defined as the probability that a device will perform its intended function, under operating condition, for a specified period of time, there is a profound irony about reliability prediction problem. In this paper, we proposed four-phase modeling procedure for function-centered reliability prediction. The proposed modeling procedure consists of four models; 1) structure block model, 2) function block model, 3) device model, and 4) reliability prediction model. We performed function-centered reliability prediction for electronic ballast using the proposed modeling procedure and MIL-HDBK-217F which is the military handbook for reliability prediction of electronic equipment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.2
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• pp.13-26
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• 2001

This paper presents the network security modeling methodology and simulation using the hierarchical and modular modeling and simulation framework. Recently, Howard and Amoroso developed the cause-effect model of the cyber attack, defense, and consequences, Cohen has been proposed the simplified network security simulation methodology using the cause-effect model, however, it is not clear that it can support more complex network security model and also the model-based cyber attack simulation. To deal with this problem, we have adopted the hierarchical and modular modeling and simulation environment so called the System Entity Structure/Model Base (SES/MB) framework which integrates the dynamic-based formalism of simulation with the symbolic formalism of AI. Several simulation tests performed on sample network system verify the soundness of our method.

• The Journal of Society for e-Business Studies
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• v.11 no.3
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• pp.73-88
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• 2006

As a computerized application for controlling enterprise processes, BPM(Business Process Management) has been received such concerns that many solution vendors developed their own process definition and storage methods. The fact causes the needs of process modeling standards for process model exchange and at the same time, requires the appropriate methodology for adopting the global standards. In this paper, we propose a transformation methodology of BPMN-based file into XMI(XML Metadata Interchange)-based neutral file format. We devised translation templates for 21 workflow patterns, and compared the results with BPEL4WS(Business Process Execution Language for Web Services) translation. As a result, our XMI transformation model enables more complete translation of process model in comparison with existing model, and thus can be practically utilized to the BPM vendors adopting BPMN standards.

• The Journal of Information Systems
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• v.13 no.1
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• pp.77-95
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• 2004

According to the increase of organizational complexity and the change of rapid information technology environment, many firms have shifted their information technology(IT) strategy from developing information systems in-house to purchasing application software such as Enterprise Resource Planning(ERP) Systems. Marketing and Sales functions within a Korean automotive part company include developing new assembly products, determining pricing, taking customer's orders, and shipping assembly products to customers. Marketing and Sales Information System(MSIS) in ERP system plays an important role in next Production Planning process. MSIS also makes management reporting and decision making faster and more uniform throughout an organization. MSIS promotes thinking about corporate goals, as opposed to thinking only about the goals of a single department or functional area. This paper intends to design and implement a MSIS in ERP systems for Korean automotive part company using object-oriented methodology In order to accomplish the implementation of MSIS in ERP system, we employed UML as its standard modeling language. In this study, four diagramming techniques such as use case diagram, sequence diagram, class diagram, component diagram among eight modeling techniques are used for analyzing hierarchical business process. In traditional marketing and sales function, a company with an unintegrated information system can have marketing and sales data that is data redundant or inaccurate. MSIS integrated in ERP system can solve the sales forecast problem, which minimizes the total costs of production, inventory, and transportation under constraints of production capacity. Also, the use of UML methodology makes S/W programmers shorten the phase of analysis and design in the implementation of MSIS system, and increase the reuse of software and the interoperability with corporate internal Information system.

• Journal of KIISE
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• v.42 no.9
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• pp.1147-1161
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• 2015

The ISO/IEC 11179 Metadata registry (MDR) is an international standard that was developed to register and share metadata. ISO/IEC 11179 represents an MDR as a metamodel that is an object model. However, it is difficult to develop an MDR based on ISO/IEC 11179 because the standard has no clear criteria to transform the metamodel into a database. In this paper, we suggest the design of an MDR data model that is based on object-relational transformation methodology (ORTM) for the MDR implementation. Hence, we classify the transformation methods of ORTM according to the corresponding relationships. After classification, we propose modeling rules by defining the standard use of the transformation. This paper builds the relational database tables as an implementation result of an MDR data model. Through experiments and evaluation, we verify the proposed modeling rules and evaluate the suitability of the created table structures. As the result, the proposed method shows that the table structures preserve classes and relationships of the standard metamodel well.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.357-360
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• 2001

As SOC design methodology becomes popular, processors, the essential core in embedded system are required to be designed fast and supported to customers with expansive behavior description. This paper presents new methodology to meet such goals with designer configurable instruction set simulator for processors. This paper proposes new language called PML(Processor Modeling Language), which is based on microprogramming scheme and is also successful in most behavior of processors. By using this, we can describe scalar processor very efficiently with by-far faster simulation speed in compared with HDL model.