• 한국해양학회지
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• 제16권1호
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• pp.12-23
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• 1981

A numerical experiment is made in order to clarify the mechanism of the upwelling phenomenon along the coast near the poleward edge of the western boundary current. The possibility of the upwelling is suggested from the analysis of the observational data in the east of Honshu, Japan, and in the south eastern coast of Korean Peninsula. This upwelling phenomenon is very deep and can be traced to the bottom layer. The upwelling phenomenon seems to be a general oceanic feature which characterizes the region along the west coast near the poleward edge of the western boundary current. This experiment is simulating the oceanic condition of the transition region between Kuroshio front and the Oyashio front in the east of Honshu, Japan. The possible explanations of the causes of the upwelling are as follows;In the interior of the modeled ocean the cold heavy water supplied from the north and the warm light water from the south make the north-south gradient of the pressure field and accelerate the eastward current to produce the h-orizontal divergence feld near the west coast. The divergence is compensated by the upwelling near the separation region. Another one is that the upwell-ed cold water strengthen constantly the pressure gradient which is balanced by the northward current and is weakened by the horizontal diffusion.

• 에너지공학
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• 제23권4호
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• pp.112-122
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• 2014

A main steam line break (MSLB) test at the ATLAS facility was simulated using the best-estimate thermal-hydraulic system code, MARS-KS. This has been performed as an activity at the third domestic standard problem for code benchmark (DSP-03) that has been organized by Korea Atomic Energy Research Institute (KAERI). The results of the MSLB experiment and the MARS input data prepared for the previous DSP-02 using the ATLAS facility were provided to participants. The preliminary MSLB simulation using the base input data, however, showed unphysical results in the primary-to-secondary heat transfer. To resolve the problems, some improvements were implemented in the MARS input modelling. These include the use of fine meshes for the bottom region of the steam generator secondary side and proper thermal-hydraulics calculation options. Other input model improvements in the heat loss and the flow restrictor models were also made and the results were investigated in detail. From the results of simulations, the limitations and further improvement areas of the MARS code were identified.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권3호
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• pp.349-355
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• 2013

This paper presents the multi-objective optimisation of an Inductive Coupled Power Transfer (ICPT) device. A setup as complicated as the one at hand in this paper is extremely hard to model analytically. To acquire some knowledge about the influence of the geometric factors, a sensitivity analysis is first performed using design of experiment (DoE) and finite-element modelling (FEM). It allows validating that the choice of the free factors is relevant. This being done, the optimisation itself is performed using a genetic algorithm (GA), with two objectives and a strict functioning constraint.

• 전기학회논문지
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• 제60권2호
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• pp.239-244
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• 2011

Due to large demand, the increase of fault current has caused the capacity of power machines in power grid to increase. Among several countermeasures, the superconducting fault current limiter (SFCL) has been noticed as one of the promising countermeasures to solve these problems. However, in spite of excellent current limiting performances of the SFCL, the application of SFCL to power system has been delayed due to both the limited space for the SFCL's installation and its longer recovery time after the fault removal. In order to solve these problems, a hybrid type SFCL was developed. In this paper, we studied the operation characteristics of the hybrid SFCL with first half cycle non-limiting operation by modelling using PSCAD/EMTDC and experiment. It was shown through the simulation using PSCAD/EMTDC and the simulated experiment that the fault current limiting and the fast recovery operations of the hybrid SFCL with the first half cycle non-limiting operation were achieved.

• 유통과학연구
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• 제19권11호
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• pp.59-68
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• 2021

Purpose: The Covid-19 pandemic has had excessively severe impacts on all the nodes and edges of any supply chain due to changes in consumer behaviours and lockdown restrictions from governments among countries. This article aims to provide a simulating experiment on how a supply chain deals with supply disruption risks by flexibility in the inventory level of each sector as a buffer considering the overall cost to fulfil demand in the market. Research design, data and methodology: Agent-based simulation techniques are used to determine the cost-efficiency and customer waiting time related to varying inventory levels of each member in the supply chain when using inventory buffers. Findings: This study has shown that any sudden changes in the inventory level of each sector are likely to impact the rest of the supply chain. Among all sectors, the wholesaler will be impacted more severely than others. Also, the manufacturing sector is the most suitable node to adjust inventory depending on its manufacturing ability. Conclusion: The findings of the study provide insightful implications for decision-makers to adjust inventory levels and policymakers to maintain manufacturing activities in the context of the pandemic restrictions to deal with the excessive demand and potential supply disruption risks.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.712-714
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• 2002

Through the Standard of UL489, the Adjustable Type Instant Trip Unit should NO trip at 80% of each current from $5{\times}In$ to $10{\times}In$ and trip 130% of those. In this paper, we obtain the attraction force between Fixing Magnet and Moving Armature. we simulated the modelling by 3D Finite Element Method. With values of experiment and simulated values, in this paper, we show the method for set up the process of designing Instant spring.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.115-118
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• 1996

This paper studies on an active noise control to reduce noise sound level in a small cavity. Ideally, high gain control solves this problem, but, in practice, there exist nonlinear characteristics and modelling errors of the small cavity, which make the control more complicated. H$_{\infty}$ control can be used in an uncertain system after determining uncertain boundary and solved algebraically or numerically. In this paper, the numerical one, LMI(Linear Matrix Inequality), is used to get controller. Finally, experiment result shows the performance of the controller..

• 대한전기학회논문지:시스템및제어부문D
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• 제51권12호
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• pp.562-570
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• 2002

The Purpose of this paper is to design and manufacture an educational system in order to demonstrate the causes and effects of electromagnetic induction.'rho educational system described in this study is a "jumping ring apparatus". This system demonstrates the principle of electromagnetic induction, a force from AC sources, Lenz's law of repulsion and transformer. The educational system is composed of a jumping ring apparatus, a sensor array, encoder, A/D converter, D/A converter and nonlinear controller. The educational system is controlled by 586 PC using Turbo C program. The sensor array is composed of 20 optical sensors. The nonlinear controller consists of nonlinear control algorithm and control board included SCR, FET and phase controller. The A/D converter is used to show the height of ring position to analog for an education purpose. The control signal calculated from the nonlinear control of algorithm send control board through 8 bit D/A convertor. Experiment results are given to verify that Proposed nonlinear controller is useful in on line control of the educational system.al system.

• 전자공학회논문지B
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• 제33B권4호
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• pp.41-51
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• 1996

This paper presents a fuzzy data fusion scheme which can analyze the sensor condition, the strength and location of a force applied to a test material. These can be realized by the modelling and fusioning of sensor signals and sensor properties. The technique uses, as the inference variables, relative magnitude of data (RMD), absolute magnitude of data (AMD) initial state (IS), synchronized relational function (SRF) and asynchronized relational function (ARF). To show the usefulness of this scheme, an experiment on the cantilever bar and six strain gages is carried out. The location of the force is inferred from SRF and ARF and the strength from RMD and AMD. In particular, the strength is compared with the measurement data of the force sensor.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.298-303
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• 1997

Over the last few year, there has been a growing interest in quantitative representation of heat transfer phenomena in weld pools in order to relate the processing conditions to the quality of the weldment produced and to use this information for the optimisation and robotization of the welding process. Normally, a theoretical model offers a powerful alternative to check out the physical concepts of the welding process and to calculate the effects of varying any of parameters. To solve this problem, a transient 2D(two-dimensional) heat conduction were developed for determining bead geometry and temperature distribution for the GMA welding process. The equation was solved using a general thermofluid-mechanics computer program, PHOENICS code, which is based on the SIMPLE algorithm. The simulation results showed that the calculated bead geometry from the developed models reasonablely agree with the experiment results.