• International Journal of Contents
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• v.5 no.4
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• pp.88-93
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• 2009

It is important for communication networks to possess the capability to overcome failures and provide survivable services. We address modeling and analysis of performability affected by both performance and availability of system components for a token ring network under failure and repair conditions. Stochastic reward nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. In this paper, hierarchical SRN modeling techniques are used to overcome state largeness problem. The upper level model is used to compute availability and the lower level model captures the performance. And Normalized Throughput Loss (NTL) is obtained for the composite ring network for each node failures occurrence as a performability measure. One of the key contributions of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performability analysis for a token ring network under SRN reward concepts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3999-4005
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• 2013

We forecast that the scale of mobile market will be large scale according to the twenty million times of smart phone's user is arrived. The type of software development is being transferred into mobile-based App. or cloud computing-based service from web-based software. Currently both Google's android and Apple's IOS are known for two prominent platforms. Existing modeling techniques cannot be applied into the case of mobile application which is executed those platforms. Therefore, we suggest a modeling technique that is customized existing modeling techniques into android-based software development. That is, we propose an analysis and design techniques which are needed into android-based mobile smart environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1343-1351
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• 2000

Thermally induced errors have been significant factors affecting the machine tool accuracy. In this paper, the spindle thermal error has been focused, where the 5 degree of freedom thermal error components are considered. An effective measurement system has been devised for the 5 DOF thermal errors, consisting of gap sensors and thermocouples around the micro-computer interfaced environment. Several thermal error modeling techniques are also implemented for the thermal error prediction: multiple linear regression, neural network and system identification methods, etc. The performance of the thermal error modeling techniques is evaluated and compared, giving the system identification method as the optimum model having the least deviation. The developed system for the thermal error measurement and modeling was practically applied to a CNC machining center, and the spindle thermal errors were effectively compensated around the micro computer-machine tool interfaced networks. The machine tool accuracy was improved about 4-5 times typically.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.25-32
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• 2005

Modeling techniques of piled pier were reviewed and the influences of pile cap's boundary conditions were analyzed in this study. Among various modeling techniques, equivalent cantilever method seems relatively simple for modeling pile groups and it has some problems to determine the virtual fixed points. Through the analyses, it was found that the method of nonlinear p-y model with soil springs was more appropriate than equivalent cantilever method. The method modeling a pile group using stiffness matrix seems useful for practical design, which can represent the nonlinear three-dimensional behavior of a piled pier. In this study, the stiffness matrix of a pile group could be estimated efficiently and precisely using three-dimensional nonlinear analysis programs of pile groups (FBPier 3.0, YSGroup).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.96-101
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• 2008

The field of load modeling has attracted the attention since it plays an important role for improving the accuracy of stability analysis and power flow estimation. Also, load modeling is an essential factor in the simulation and evaluation of power system performance. However, conventional load modeling techniques have some limitations with respect to accuracy for nonlinear and composite loads. Thus, precision load modeling technique and reasonable application method is needed for more accurate power system analysis. In this paper, we develop an intelligent load modeling method based. on neural network and application techniques for power system. The proposed method makes it possible to effectively estimate the load model for nonlinear models as well as linear models. Reasonable application method is also proposed for stability analysis. To demonstrate the validity of the proposed method, various experiments are performed and their results are presented.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1263-1268
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• 2011

Rail infrastructure manager and operators shall establish emergency response plans. Emergency Response Planning Activities expanded coincidence events should be modeled. Identify the emergency response organization for the purpose of knowledge is required. In other words, control concepts and skills needed core elements. Structured analysis & design technic methodology is Compared with other modeling techniques through a simple graphical model is visualized. The information contained in a model real problems that considering the state of the system activities, so that knowledge acquired in situations where the modeling becomes possible. In this paper, using structured analysis techniques, infrastructure deployment model of the proposed features. In addition to emergency response planning in the 1960s in Germany, Karl Petrie (Carl Petri) devised various means of modeling the situation presents a Petri net model.

• Journal of Korea Multimedia Society
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• v.22 no.1
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• pp.99-109
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• 2019

Realistic rendering of natural phenomena is a difficult problem. Many environmental factors must be considered to simulate this phenomenon. At the same time, we need to think about their computational complexity to be simulated with computer algorithm One of the most difficult problems in creating weather conditions is the rain. To simulate realistic rainy scene, you have to consider the physical properties of rain and the environmental where the rain is falling down as well. In this paper, we survey the modeling and rendering techniques for realistic rainfall scenes from three different aspects. First, we list up techniques for modeling raindrop dynamics. Second, we survey the rendering techniques that render the raindrop in the environment. Third, we take a look at the hybrid methods that combines the rendering the modeling at the same time. For each aspect, we compare the algorithms in terms of implementation and their speciality.

• Journal of the Korean Society for Railway
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• v.3 no.4
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• pp.219-228
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• 2000

This paper presents an advanced approach to simulate AC electric railway system in steady-state. The algorithm consists of two parts. One is circuit modeling of elements of electric railway system, the other is an analysis on electric circuit. The modeling procedure has two steps, in the first step, proposed is the modeling method which is considered to be an internal impedance of the autotransformers and mutual impedances between the feeding systems. For the load(locomotives) modeling which is the second step, improved results are obtained as application to the proposed constant power model compared with constant impedance model. In the analysis on electric circuit, a generalized analysis method using the loop equation has been proposed and there is no limit in the number of trains between the ATs. In addition, the computer simulation by the proposed model was practiced. Simulation result seems very reasonable. It is therefore concluded that techniques for the electric circuit modeling and analysis have been established. Accuracy of the techniques will be further investigated.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.167-172
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• 2020

The importance of modeling in large-scale software development has already been confirmed. In most of the projects, modeling is done using UML. However, UML is a class-based modeling tool, which is complicated and lacks in modeling common modules, components, processes, and data. To supplement this point, this paper will help the actual industrial field by suggesting the integration of various modeling techniques, including structural methodology and information engineering methodology developed in the computer field. Through this paper, I would like to show that it is useful to use various methodologies instead of using UML to develop software that satisfies customers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1410-1414
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• 2007

In modern automobile body manufacturing, the structural adhesive bonding is recognized to one of new joining techniques for the purpose of light weight body and its application scope in the automobile body has been gradually magnified. Specially, the structural adhesives have the advantages of not only enhancing the design flexibility of automobile body, but also improving automobile performances such as stiffness, crashworthiness and durability. In order to evaluate the performance simulation of the automobile body applied with structural adhesives, it is necessary to develop modeling techniques in the structural adhesives in advance. This paper aims to investigate modeling methodology of structural adhesive junctions for body stiffness simulation. Two main modeling points are the element selection for adhesives and the connectivity between adhesives and adherends. Both of the 1D element used in classical modeling and the 3D element which are more accurate are considered for the adhesives, and the congruent and incongruent mesh models of the adherends are compared for connectivity modeling. By applying the several kinds of modeling methodology to the simple structures, the simulation results are compared and some modeling guidelines are obtained.