• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.839-844
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• 2008

A novel state of health estimation method for hybrid electric vehicle lithium battery using sliding mode observer has been presented. A simple R-C circuit method has been used for the lithium battery modeling for the reduced calculation time and system resources due to the simple matrix operations. The modeling errors of simple model are compensated by the sliding mode observer. The design methodology for state of health estimation using dual sliding mode observer has been presented in step by step. The structure of the proposed system is simple and easy to implement, but it shows robust control property against modeling errors and temperature variations. The convergence of proposed observer system has been proved by the Lyapunov inequality equation and the performance of system has been verified by the sequence of urban dynamometer driving schedule test. The test results show the proposed observer system has superior tracking performance with reduced calculation time under the real driving environments.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.453-458
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• 2017

A study on the modeling of the methane Chemical Looping Reforming system was carried out. It is aimed to predict the temperature and concentration behavior of the product through modeling of oxygen carrier fixed bed reactors composed of multiple stacks. In order to design the reaction system, first of all, the flow rate of the hydrogen to be produced was calculated. The flow rate ratio of the oxidation/reduction reactor was calculated considering the heat of reaction between adjacent reactors. Finally, in this paper, kinetic model including empirical coefficients was suggested.

• Journal of the Korean Society of Combustion
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• v.5 no.2
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• pp.9-17
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• 2000

A brief introduction is given on the conditional moment closure model for turbulent nonpremixed combustion. It is based on the transport equations derived through a rigorous mathematical procedure for the conditionally averaged quantities and appropriate modeling forms for conditional scalar dissipation rate, conditional mean velocity and reaction rate. Examples are given for prediction of NO and OR in bluffbody flames, soot distribution in jet flames and autoignition of a methane/ethane jet to predict the ignition delay with respect to initial temperature, pressure and fuel composition. Conditional averaging may also be a powerful modeling concept in other approaches involved in turbulent combustion problems in various different regimes.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.69-73
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• 2002

A study on photovoltaic system has a lot of problems. Such as repetition experiment in the same condition, development of MPPT(Maximum Power Point Tracking) algorithm, development of islanding detection algorithm and so forth. The reason Is that solar cell output characteristics are varied by insolarion and surface temperature of solar cell. Therefore, the assistance equipment is required which emulates the solar cell characteristics. In this paper, propose the new modeling of solar cell and verify this modeling using MATLAB simulation. And experiment virtual implement of solar cell system using this modeling.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.373-374
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• 2009

Three autogenous expansion model of MgO concrete are investigated in order to access their suitability in stress analysis which consider temperature and volume change due to hydration of cement and temperature dependent expansion of MgO.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.239-239
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• 2000

This paper present experimental results on temperature trajectory tracking. The benefits of precalculated feedforward input together with PID feedback control are demonstrated by experimental results. To find the feedforward input, the plant (autoregresiive) model is first identified and convex optimization procedure is applied. PID controller is then implemented based on Ziegler-Nickels tuning rule to reduce effects of disturbances and modeling errors. Experimental results show an improvement in slope tracking performance over the fully PID controller.

• Applied Science and Convergence Technology
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• v.26 no.6
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• pp.184-188
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• 2017

Polymer deposition pattern on the ceramic lid surface is analyzed by numerical modeling. Assumption was made that is affected by gas flow pattern from the horizontal and vertical nozzles, temperature profile from the finger-like branches made of graphite and electrostatic potential effect. Calculated results showed gas flow dynamics is less relevant than two others. Temperature and electrostatic effects are likely determining the polymer deposition pattern based on our numerical simulation results.

• Journal of computational fluids engineering
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• v.19 no.3
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• pp.14-19
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• 2014

The flow characteristics of inertance pulse tube cryocooler(IPTC) was investigated with a computational thermal fluid dynamics for the reciprocating flow in IPTC including the piston movement of linear compressor. Two dimensional axisymmetric modeling was applied for the flow in an IPTC with a clearance between the piston and cylinder wall of linear compressor. The pressure, velocity, and temperature distribution were examined for the steady state. These were compared with previous results to confirm the validity in the modeling and computational results. The leakage between piston and cylinder wall affect the cooling capacity seriously. The dependence on mesh numbers were also examined to obtain a proper mesh numbers to improve the accuracy of calculation, which showed significant effect on the results. The user-defined function was used for the process of compression and expansion of piston.

• Journal of the Korean Society of Combustion
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• v.16 no.4
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• pp.23-30
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• 2011

In the iron and steel manufacturing, sintering process precedes blast furnace to prepare feed materials by agglomerating powdered iron ore to form larger particles. There are several techniques which have devised to improve sintering production and productivity including flue gas recirculation(FGR) and additive gas enriched operation. The application of those techniques incurs variations of process configurations as well as inlet and outlet gas conditions such as temperature, composition, and flow rate which exert direct influence on reactions in the bed or the operation of the entire plant. In this study, an approach of sintering bed modeling using flowsheet process simulator was devised in consideration of FGR and the change of incoming and outgoing gas conditions. Results of modeling for both normal and FGR sintering process were compared in terms of outgoing gas temperature, concentration, and moisture distribution pattern as well as incoming gas conditions. It is expected to expand the model for various process configurations with FGR, which may provide the usefulness for design and operation of sintering plant with FGR.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.1-9
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• 2016

In this study, thermal-hydrological-chemical modeling for the alteration of a bentonite buffer is carried out using a simulation code TOUGHREACT. The modeling results show that the water saturation of bentonite steadily increases and finally the bentonite is fully saturated after 10 years. In addition, the temperature rapidly increases and stabilizes after 0.5 year, exhibiting a constant thermal gradient as a function of distance from the copper tube. The change of thermal-hydrological conditions mainly results in the alteration of anhydrite and calcite. Anhydrite and calcite are dissolved along with the inflow of groundwater. They then tend to precipitate in the vicinity of the copper tube due to its high temperature. This behavior induces a slight decrease in porosity and permeability of bentonite near the copper tube. Furthermore, this study finds that the diffusion coefficient can significantly affect the alteration of anhydrite and calcite, which causes changes in the hydrological properties of bentonite such as porosity and permeability. This study may facilitate the safety assessment of high-level radioactive waste repositories.