• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.21-23
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• 2013

Various solid particle materials are treated in the industrial processes including fixed-beds or moving grate beds, and modeling approaches have been widely applied to the processes to predict and evaluate their performance. For this study, the modeling approach was applied to iron ore sintering process with various improvement measures. Based on the previous modeling approach, the changes and effects of the improvement measures were discussed at the point of controlling the combustion environment in the bed.

• Journal of Power Electronics
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• v.9 no.5
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• pp.757-771
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• 2009

This paper proposes a systematic approach to the modeling of the small-signal characteristics of three-phase bridge boost rectifiers under non-sinusoidal conditions. The main obstacle to the conventional synchronous d-q frame modeling approach is that it is unable to identify a steady-state under non-sinusoidal conditions. However, for most applications under non-sinusoidal conditions, the current loops of boost rectifiers are designed to have a bandwidth that is much higher than typical harmonics frequencies in order to achieve good current control for these harmonic components. Therefore a quasi-static method is applied to the proposed modeling approach. The converter small-signal characteristics developed from conventional synchronous frame modeling under different operating points are investigated and a worst case point is then located for the current loop design. Both qualitative and quantitative analyses are presented. It is observed that operating points influence the converter low frequency characteristics but hardly affect the dominant poles. The relationship between power stage parameters, system poles and zeroes is also presented which offers good support for the system design. Both the simulation and experimental results verified the analysis and proposed modeling approach. Finally, the practical case of a parallel active power filter is studied to present the modeling approach and the resultant regulator design procedure. The system performance further verifies the whole analysis.

• ETRI Journal
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• v.37 no.1
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• pp.175-185
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• 2015

This paper presents a system-of-systems (SoS) approach to the formal modeling of a cyber-physical system (CPS) for simulation-based analysis. The approach is based on a convergence technology for modeling and simulation of a highly complex system in which SoS modeling methodology, hybrid systems modeling theory, and simulation interoperation technology are merged. The methodology maps each constituent system of a CPS to a disparate model of either continuous or discrete types. The theory employs two formalisms for modeling of the two model types with formal specification of interfaces between them. Finally, the technology adapts a simulation bus called DEVS BUS whose protocol synchronizes time and exchange messages between subsystems simulation. Benefits of the approach include reusability of simulation models and environments, and simulation-based analysis of subsystems of a CPS in an inter-relational manner.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.2
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• pp.91-103
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• 2003

Use case modeling on UML (Unified Modeling Language) is getting widely used in OOAD and CBD and it is considered a useful technique in dealing with the complexity of the requirements analysis. However, some of the problems with use case modeling are that it is not structured, difficult to handle non-functional requirements, and to analyze impacts among use cases. To alleviate these problems, we propose a scenario-based goal-oriented approach for use case modeling. The proposed approach is to apply a goal-oriented analysis method to use case modeling. Since goal-oriented analysis method is not systematic and many heuristics are involved, we have adopted scenarios as the basis for goal extraction. The proposed method is applied to CBIS (City Bus Information Subsystem) in ITS (Intelligent Transportation System) domain. The proposed approach helps software engineers to analyze the impact among use cases and represent non-functional requirements.

• International Journal of CAD/CAM
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• v.2 no.1
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• pp.13-21
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• 2002

It is not possible to exchange parametric information of CAD models based on the current version of STEP. The design intent can be lost during the STEP transfer of CAD models. The Parametrics Group of ISO/TC184/SC4 has proposed the SMCH schema, which includes constructs for exchange of parametric information. This paper proposes a macro-parametric approach that is intended to provide capabilities to transfer parametric information including design intents. In this approach, CAD models are exchanged in the form of macro files. The macro file contains the history of user commands, which are used in the modeling phase. To exchange CAD models using the macro-parametric approach, the modeling commands of several commercial CAD systems are analyzed. Those commands are classified and a set of standard modeling commands has been defined. Mapping relations between the standard modeling commands and the native modeling commands of commercial CAD systems are defined. The scope of the current version is limited to parts modeling, not assemblies.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.127-136
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• 2021

In the systems and software modeling field, a conceptual model involves modeling with concepts to support development and design. An example of a conceptual model is a description developed using the Unified Modeling Language (UML). UML uses a model multiplicity formulation approach, wherein a number of models are used to represent alternative views. By contrast, a model singularity approach uses only a single integrated model. Each of these styles of modeling has its strengths and weaknesses. This paper introduces a partial solution to the issue of multiplicity vs. singularity in modeling by adopting UML use cases and class models into the conceptual thinging machine (TM) model. To apply use cases, we adopt the observation that a use-case diagram is a description that shows the internal structure of the part of the system represented by the use case in addition to being useful to people outside of the system. Additionally, the UML class diagram is recast in TM representation. Accordingly, we develop a TMUML model that embraces the TM specification of the UML class diagram and the internal structure extracted from the UML use case. TMUML modeling introduces some of the advantages that have made UML a popular modeling language to TM modeling. At the same time, this approach supplies UML with partial model singularity. The paper details experimentation with TMUML using examples from the literature. Our results indicate that mixing UML with other models could be a viable approach.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.157-185
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• 1998

One of the essential issues in model systems is how to represent and manipulate mathematical modeling knowledge. As the bases of integrated modeling environments, current modeling frameworks have limitations: lack of facility to coordinate different users perpectives and lack of mechanism to reuse modeling knowledge. In this paper, multi-facetted modeling approach is proposed as a basis for the development of integrated modeling environment which provides facilities for (1) independent management of modeling knowledge from individual models； (2) object-oriented conceptual blackboard concept； (3) multi-facetted modeling； and (4) declarative representation of mathematical knowledge. The proposed multi-facetted approach is illustrated using multicommodity transportation models.

• Korean Journal of Computational Design and Engineering
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• v.5 no.1
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• pp.12-22
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• 2000

Network and Internet technology opens up another domain for building future CAD/CAM environment. The environment will be global, network-centric, and spatially distributed. In this paper, we present an approach for network-centric feature-based modeling in a distributed design environment. The presented approach combines the current feature-based modeling technique with distributed computing and communication technology for supporting product modeling and collaborative design activities over the network. The approach is implemented in a client/server architecture, in which Web-enabled feature modeling clients, neutral feature model server, and other applications communicate with one another via a standard communication protocol. The paper discusses how the neutral feature model supports multiple views and maintains naming consistency between geometric entities of the server and clients. Moreover, it explains how to minimize the network delay between the server and client according to incremental feature modeling operations.

• Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.121-131
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• 2016

Organic modeling of 3D characters is a challenging task when it comes to correctly modeling the anatomy of the human body. Most sketch based modeling tools available today for modeling organic models (humans, animals, creatures etc) are focused towards modeling base mesh models only and provide little or no support to add details to the base mesh. We propose a hybrid approach which combines geometrical primitives such as generalized cylinders and cube with Shape-from-Shading (SFS) algorithms to create plausible human character models from sketches. The results show that an artist can quickly create detailed character models from sketches by using this hybrid approach.

• Korean Journal of Computational Design and Engineering
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• v.6 no.4
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• pp.254-262
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• 2001

It is not possible to exchange parametric information of CAD (Computer Aided Design) models based on the current version of STEP (Standard leer the Exchange of Product model data). The design intent can be lost during the STEP transfer of CAD models. The ISO Parametrics Group has proposed the SMCH (Solid Model Construction History) schema in June 2000 that includes structures fur exchange of parametric information. This paper proposes the macro parametric approach that is intended to provide capabilities to transfer parametric information. In this approach, CAD models are exchanged in the form of macro files. The macro file contains user commands which are used in the modeling phase. To exchange CAD models using the macro parametric approach, modeling commands of commercial CAD systems are analyzed. Those commands are classified by the grouping method suggested by Bill Anderson. As a neutral file format, a standard modeling commands set has been defined. Mapping relations between the standard modeling commands set and the native modeling commands set of commercial CAD systems are defined.