• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.16-22
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• 2020

The characteristics of the LCL filter for grid-connected inverters have been discussed in academia and industry. An online simulation tool was applied to compare and analyze the difference between the LCL filter and L filter. LCL filters were modeled and simulated using a range of professional simulation simulators, and the LCL filters were found to have good filtering effects for high-frequency harmonics. First, this paper summarizes the transfer functions of the LCL filter and provides the Bode plot diagram. The accuracy and validity of the filter attenuation characteristics were confirmed by a fast Fourier transform based on off-line simulation tools, such as PSIM and MATLAB, depending on the given parameters of the LCL filter. Finally, the Typhoon HIL402 real-time simulation was performed for hardware in the loop simulation to verify the actual filtering characteristics of the LCL filter.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.127-135
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• 2010

Modern marine navigation requires officers on the bridge to monitor a torrent of data on both the insides and outsides of the ship from numerous useful devices. But despite these tools, navigators can still find it difficult to make a safe decision for two reasons: one is that too much data if provided too quickly tends to cause fatigue and overwhelm the officer, and the other is that any inconsistency across data from several different types of devices can lead to confusion. Indeed, the fact remains that the many marine accidents can be attributed to human error, and hence there is a strong need for decision-support tools for marine navigation. One technique of providing decision support is through the use of simulation to evaluate or predict system dynamics over time using an accurate model. This paper, as a simulation method for risk prediction for a navigation safety information system of ship, suggests a navigation prediction simulation system using various knowledge bases and discrete event simulation methodology, and supports the validity of the system through the examples of components in a restricted navigation situation scenario.

• IE interfaces
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• v.13 no.3
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• pp.288-295
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• 2000

As the industrial environment becomes more competitive, supply chain management(SCM) has become recognized as a major strategy in the business world. Despite its current widespread popularity, its basic concepts are confused with those of other exiting logistic tools and not clearly understood. This paper introduces the current status of SCM in terms of physical logistics, interrelationship with other logistic tools as well as the general history and definitions of SCM. Researches are categorized into deterministic models, stochastic models, simulation models, and several future research areas are discussed in this paper.

• Journal of applied mathematics & informatics
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• v.3 no.2
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• pp.205-216
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• 1996

The field of nonparametrics has shown its appeal in re-cent years with anarray of new tools for statistical analysis. As one of those tools nonparametric regression has become a prominent statis-tical research topic and also has been well established as a useful tool. In this article we investigate the biased cross-validation selector, BCV, which is proposed by Oh et al. (1995) for a less smoothing regression function. In the simulation study BCV selector is shown to perform well in parctice with respect to ASE ratio.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.30
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• pp.167-175
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• 1994

Generally, queueing networks, networks, chains and simulation techniques are among the most widely used evaluation tools to study computer systems, manufacturing systems etc. But, these tools have some assumptions and difficulties. So, this thesis presents a method for manufacturing system using Petri nets. Petri nets are a graphical and mathmatical modeling tool and are promising tool for describing and studying systems that are characterized as being concurrent asychronous, dynamic, distributed and parrallel. It designs Petri net model for processing time of manufacturing system And it applied to a job shop system composed of 8 machines and 4 different job types.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.282-290
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• 1998

In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes tool life depends on wear over 70%. In this study finite element analyses are con-ducted to warm and hot forging by adopting suggested wear model. By comparison of simulation and eal profile of die suggested wear model. By comparison of simulation and real profile of die suggested model is verified.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.7-14
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• 2015

The machine tools builders are trying to improve the efficiency and performance of the machine tools. The electro-mechanical driven broaching machine has many advantages such as lower noisy operating, higher energy efficiency, and smaller space of installation. This paper presents the structural and mechanical development of an electro-mechanical driven broaching machine that is replaced for traditional hydraulic one. The servo motor, ball screw and roller linear guide are used instead of hydraulic cylinder and translation frictional sliding guides. The simulation method based on FEM was applied to analyze the stress, deformation of the machine for static analysis. The dynamic analysis was carried out for verifying and assessing the mechanical behavior of the developed broaching machine. This work helps broaching machine developer make a better product at the early design stage with lower cost and development time.

• Progress in Superconductivity
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• v.4 no.1
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• pp.37-41
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• 2002

In this work. we have designed two different kinds of Rapid Single Flux Quantum (RSFQ) OR-gates. One was based on the already developed RSFQ cells and the other was aimed to develop a more compact version. In the first circuit, we used a combination of two D Flip-Flops and a merger and in the other circuit we used a combination of RS Flip-Flops and Confluence Buffer. We tested the circuit performance by using the simulation tools, Xic and Wrspice. We obtained the operation margins of the circuit elements by a margin calculation program, and we obtained the minimum operation margins of $\pm$30%. The circuits were laid out, aimed to fabricate by using the existing KRISS Nb process. KRISS Nb process includes the $Nb／Al_2$$O_3$／Nb trilayer fabricated by DC magnetron sputtering and the reactive ion etching technique for the definition of the features. The major tools used in the layouts were Xic and L-meter.

• IE interfaces
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• v.9 no.3
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• pp.157-167
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• 1996

Due to the drastic technological innovation and introduction of various kinds, of new communication services, the structure and operation of communication networks are becoming complicated and diversified more and more. Accordingly, the necessity of flexible simulation tools which can be utilized for various performance evaluation jobs in various types of communication networks is growing. In this article, various existing simulation tools are briefly surveyed and the requirements for the simulator dedicated for the performance evaluation of communication networks are discussed. Then, a strategy to develop a simulator dedicated for the performance evaluation of communication networks is proposed. Our approach is based on the prototyping strategy, in which a relatively simple prototype structure is developed first and more functions are added whenever necessary. By following this strategy, a simulator can be developed and evolved in a timely manner at a relatively small cost.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.60-64
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• 1999

Recently in manufacturing environment, manufacturing order is characterized by unstable market demand, shorter product life cycle, a variety of product and shorter production lead time. In order to adapt this manufacturing order, flexible manufacturing system(FMS) in manufacturing technology advances into the direction that machines become further versatile functionally and that tools are controlled by fast tool delivery device. Unlike conventional FMS to mainly focus on part flow, it is important to control tool flow in single-stage multimachine systems(SSMS), consisting of versatile machines and fast tool delivery device. In this paper, in SSMS under dynamic tool allocation strategy to share tools among machines, we propose real-time part release and tool allocation algorithms which can apply real factory and which can improve system performance.