• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.620-628
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• 1991

For a Stationary moving-target. the design technique of guidance system for underwater vehicle with a seeker of st type is developed. Using perturbation theory, a new method which linearizes the nonlinear intercept geometry is proposed. On the basis of the linearized system modeling, LQ and PID design technique is used to determine the structure and gain of the guidance system. Some simulation results applied underwater engagement are represented to show that the proposed guidance law is superior to the other guidance laws as pursuit, Bang-Beng, PN APN.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.488-490
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• 2001

It is important to catch or classify fault types by any detecting technique for distribution protection. This paper proposes the technique to classify the fault types using wavelet transform in radial distribution line. Modeling of the radial distribution line is simulated using PSCAD/EMTDC and wavelet transform is performed in the Matlab program.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.147-154
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• 2003

Microarray information system is a complex system to manage, analyze and interpretate microarray gene expression data. Establishment of well-defined development process is very essential for understanding the complexity and organization of the system. We performed object-oriented analysis using Unified Modeling Language (UML) in specifying, visualizing and documenting microarray information system. The object-oriented analysis consists of three major steps: (i) use case modeling to describe various functionalities from the user's perspective (ii) dynamic modeling to illustrate behavioral aspects of the system (iii) object modeling to represent structural aspects of the system. As a result of our modeling activities we provide the UML diagrams showing various views of the microarray information system. We believe that the object-oriented analysis ensures effective documentations and communication of information system requirements. Another useful feature of object-oriented technique is structural continuity to standard microarray data model MAGE-OM (Microarray Gene Expression Object Model). The proposed modeling e(forts can be applicable for integration of biomedical information system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.109-116
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• 2007

The emf of a permanent magnet multi-phase BLAC(Brushless AC) motor is generally a non-sinusoidal or a non-ideal trapezoid wave. So, conventional modeling using a sinusoidal or an ideal trapezoid emf can result in errors to simulate and analyze the properties of a multi-phase BLAC motor. To reduce the modeling error, this paper proposes a phase variable model, which is obtained from a hybrid modeling technique consisting of Finite Element Analysis(FEA) based circuits and equations. Since the phase model parameters including the emf waveform were obtained using FEA, the proposed hybrid modeling technique can be used to implement a simulation model for multi-phase BLAC motors with any emf voltage waveforms. Adequacy of the proposed model was established from the simulation and experimental results for a seven-phase BLAC motor.

• Composites Research
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• v.16 no.5
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• pp.7-14
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• 2003

Modeling of thick composite structures for finite element analysis is relatively complicated. 2-D plane elements may cause inaccurate result since the plane stress condition cannot be applicable in these structures. Therefore a 3-D modeling should be used. However, the difficulty to model all the layers with different material properties and ply orientation arise in this case. In this paper, an equivalent modeling is proposed and numerically tested for analysis of thick composite structures. By grouping layers with same material and ply orientation, number of elements through the thickness is remarkably reduced and still the result is close enough to the one from a detail finite element model. MSC/NASTRAN and PATRAN are used for the analysis. The proposed modeling technique has been applied for analysis of composite rotor hub system designed by Korea Aerospace Research Institute(KARI). Using the proposed equivalent modeling technique, we could conduct stress analysis for the hub system and check the safety factor of each part.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.23-31
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• 1994

The compartmentation model is represented by the characteristics and geometric information of the spaces defined by the structural members which are used for the boundary planes of the compartment. For the efficient compartment modeling a program performing the compartmentation design by the chopping and merging method was presented by authors. In this research, the development of an interactive ship compartmentation modeller is introduced. It is natural that the value of the program lessens if the input process is complicated and uneasy, even though the internal techniques for the compartmentation modeling are superior. In this paper, a method for the convenient input is proposed and implemented with the help of a graphical user interface technique. The modeling method introduced in this paper performs an efficient compartmentation modeling fast and conveniently by the solid modeling concept and the graphical user interface.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.87-96
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• 2019

The objective of this study was to develop a general inundation modeling technique considering the effect of drainage delay in the paddy field districts. In most studies, farmland inundation simulations have been conducted using previously developed watershed models. However, the water cycle in the paddy fields has a different structure from that of the general watershed, and the effect of the drainage delay should be considered. In this study, the drainage delay algorithm was developed using water balance equation, and the inundation modeling was performed for inundation-prone paddy fields located near Doowol stream. As a result, the depth of inundation was 43.1 cm and 45.2 cm, respectively, due to the 100-year and 200-year frequency rainfall. With the operation of drainage pump ($0.1m^3/s$), inundation depths decreased by 5.8 cm and 6.0 cm, respectively, and inundation time reduced by 20 hours and 21 hours, respectively for the 100-year and 200-year frequency rainfall. The result showed that the general inundation modeling technique developed in this study could reflect the effect of drainage delay due to the rise of external water level and the flooding reduction effect by operation of drainage pump. The results of this study are expected to be useful to establish measures for damage caused by farmland inundation.

• Composites Research
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• v.32 no.5
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• pp.206-210
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• 2019

As the use of composite materials of woven structure has expanded to various fields such as automobile and aviation industry, there has been a need for reliability problems and prediction of mechanical properties of woven composites. In this study, finite element analysis for predicting the mechanical properties of composite materials with different weaving structures was conducted to verify similarity with experimental static properties and an effective modeling method was developed. To reflect the characteristics of the weave structure, the meso-scale representative volume element (RVE) was used in modeling. Three-dimensional modeling was carried out by separating the yarn and the pure matrix. Hashin's failure criterion was used to determine whether the element was failed, and the simulation model used a progressive failure model which was suitable for the composite material. Finally, the accordance of the modeling and simulation technique was verified by successfully predicting the mechanical properties of the composite material according to the weave structure.

• Economic and Environmental Geology
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• v.19 no.4
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• pp.283-292
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• 1986

Finite element method with linear triangular and bilinear rectangular elements is applied to solve the three-dimensional potential distribution due to a point source of current located in or on the surface of the earth containing arbitrary two-dimensional resistivity distribution. The modeling technique developed in this paper is flexible to model conductive inhomogeneity and surface topographies, and more accurate to evaluate surface potentials than the conventional techniques using finite difference method. Since it is possible to reduce nodal points with acceptable accuracy, this modeling technique is very efficient and economic in terms of execution time and core space. A few geologic structures adequate to demonstrate above features are simulated in this paper.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.134-141
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• 2003

A major research issue associated with service robots is the creation of an environment recognition system for mobile robot navigation that is robust and efficient on various environment situations. In recent years, intelligent autonomous mobile robots have received much attention as the types of service robots for serving people and industrial robots for replacing human. To help people, robots must be able to sense and recognize three dimensional space where they live or work. In this paper, we propose a three dimensional environmental modeling method based on an edge enhancement technique using a planar fitting method and a neural network technique called "Growing Neural Gas Network." Input data pre-processing provides probabilistic density to the input data of the neural network, and the neural network generates a graphical structure that reflects the topology of the input space. Using these methods, robot's surroundings are autonomously clustered into isolated objects and modeled as polygon patches with the user-selected resolution. Through a series of simulations and experiments, the proposed method is tested to recognize the environments surrounding the robot. From the experimental results, the usefulness and robustness of the proposed method are investigated and discussed in detail.in detail.