• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.82-92
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• 1996

A computer simulation with predict the fuel injection rates and the fuel injection pressure behaviors in diesel engine fuel injection systems would by very useful in designing or improving fuel injection systems. In this paper we developed computer program in order to predict the behaviors of the fuel injection rate and the injection pressure for Electronic Hydraulic Ultra-High Pressure Fuel Injection System. We've applied the continuity and momentum equations for the hydraulic phenomena and the dynamics of individual components of the Electronic Hydraulic Fuel Injection System. To solve all the equations numerically we've applied the Runge-kutta IV method. Water hammer equations were applied for the hydraulic pipe solution, and the method of characteristics was employed in our calculations. The simulation results were compared with the experimental results for: Accumulator pressure, Injection pressure and unjection rate. As a result, The simulation results agree very well with our experimental results. We found that a large accumulator and the high speed solenoid valve were required, and the compression volume of the fuel had to be as small as possible in order to acheive ultra-high pressure fuel injection.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.73-80
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• 2014

In this paper, we propose an incremental simulation method in event-driven HDL simulation to reduce the simulation execution time. In general, the simulation is repeated with a series of design changes. Incremental simulation is an efficient simulation method that shortens the simulation execution time for the following simulation by using the result of previous simulation. We have observed the effectiveness of the proposed approach through the experimentation with multiple real designs.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.1-15
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• 1989

In the past few years, increasing numbers of automatic storage/retrieval system (AS/RS) using computer controlled storage/retrieval machine have been installed. This paper introduces two modeling approaches to determine the best operating policy for AS/RS : an M/G/1 queueing model and a computer simulation model. The operating policy consists of three elements. : the operation command cycle, the storage location method, and the operation dispatching rule. The analysis based on M/G/1 model is suitable for a quick and approximate evaluation, due to its inherent strict assumptions. The computer simulation can be used to perform a more realistic analysis. It is shown through the study that a significant improvement in the throughput and/or the space requirement can be expected by determining the best operating policy to a particular system. Most important, the computer simulation demonstrates its powerful capability in evaluating dynamic stochatic systems with imperfect information.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.1
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• pp.61-71
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• 1993

We focus on a way of combining the Monte Calro methods of antithetic variates and control variates to reduce the variance of the estimator of the mean response in a simulation experiment. Combined Method applies antithetic variates (partially) for driving approiate stochastic model components to reduce the vaiance of estimator and utilizes the correlations between the response and control variates. We obtain the variance of the estimator for the response analytically and compare Combined Method with control variates method. We explore the efficiency of this method in reducing the variance of the estimator through the port operations model. Combined Method shows a better performance in reducing the variance of estimator than methods of antithetic variates and control variates in the range from 6% to 8%. The marginal efficiency gain of this method is modest for the example considered. When the effective set of control variates is small, the marginal efficiency gain may increase. Though these results are from the limited experiments, Combined Method could profitably be applied to large-scale simulation models.

• Cartoon and Animation Studies
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• s.17
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• pp.188-204
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• 2009

This study purpose development cg technique our nation because present Technique limit of Computer graphic R&D that the best competition of 3D Computer graphic part and present a answer of how to overcome Technique limit of Computer graphic R&D with success example of Computer graphic R&D an advanced country. if we make full of mutuality supplementation of C.T and I.T then hold a dominant position and the over the limit solution We researches on multi or group simulation of cyber character and water, fire, wind, fog Simulation System of Computer graphic and purpose development of direction Computer graphic R&D to people in Computer graphic the result of this study and introduction of project of a research institution and inflection method this time is a point of R&D time of determined and resolution instead creative part.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.171-178
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• 2021

In this paper, the author proposes a method for detecting modification of transmitted messages in C/C++ based Discrete Event System Specification (DEVS) simulation. When a message generated by a model instance is delivered to other model instances, it may be modified by some of the recipients. Such modifications may corrupt simulation results, which may lead to wrong decision making. In the proposed method, every model instance stores a copy of every transmitted message. Before the deletion of the transmitted message, the instance compares them. Once a modification has been detected, the method interrupt the current simulation run. The procedure is automatically performed by a simulator instance. Thus, the method does not require programmers to follow secure coding or to add specific codes in their models. The performance of the method is compared with a DEVS simulator.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.52-60
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• 2010

Knowledge of the physical locations of access point of WLAN is becoming increasingly important with the rise of location-based services. In this article, we propose a new AP localization method using neural network approach. Basic theory and properties are derived for precise outdoor AP localization using GPS location information and RSSI. Rules for neural network model are derived and simulation has finally been done to demonstrate the efficiency of the proposed method. The simulation results show that the proposed method can result in AP localization with very. low error probability.

• Tribology and Lubricants
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• v.3 no.1
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• pp.52-60
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• 1987

Many kinds of condition monitoring technique as the preventive maintenance technique have been studied, so this study has investigated the possibility of chbcking the trend in the fault diagnosis of ball bearing, one of the important elements of rotating machine, by applying the cepstral analysis method. And computer simulation is conducted in order to identify obviously the physical meaning of cepstral analysis. It is identified that cepstral analysis is effective method to distinguish between the basic and reflected wave by computer simulation, and we know that it is possible to apply the cepstral analysis to the arbitrary elements of rotating machine which are different in fundamental frequency. It is verified that cepstral analysis method is more effective than the other conventional method in bearing fault diganosis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.207-212
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• 1999

A computational method based on the three-dimensional finite element method is developed for the deformation analysis of roll forming process. the method approximates the process as a kinematically steady state deformation of strip. For industrial usefulness of the simulation method several rolls with arbitrary shapes in one stand can be considered. The shapes and the thickness distributions of strip after roll forming were examined by comparing computation results with experiments It is concluded that the tool is useful enough to predict the process. The overall simulation method was integrated into a sorftware package to help the industrial roll-design.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.89-107
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• 1999

There are many issues in computer simulation such as verifying model code, validating models, understanding the dynamics of systems and training the personnel. The developers of simulation tool have been interested in the animation since it can help solve the problems related to the above listed issues. In practice, animation is one of the popular method for displaying the simulation output for solving these problems. Trying to display all the graphic objects representing the dynamics of the models being simulated, however, causes the distraction of focus, which results in solving the above listed problems difficult. The redundant graphic objects also Increase the computer computation overhead. This paper presents a hierarchical animation environment in which the users can have better focus on the dynamics of system components. In hierarchical animation environment the users can observe the dynamics of system by selectively choosing the hierarchical level and components with in a level of the hierarchically structured model. Especially when the model is large and complex the selection of observation level is needed. The design approach of the hierarchical animator is based on the DEVS(Discrete Event system Specification) formalism which is theoretically well grounded means of expressing modular and hierarchical models.