• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.27-38
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• 2012

This study is to analyse the hydrological behavior of agricultural reservoir using CAT (Catchment hydrologic cycle Assessment Tool). The CAT is a water cycle analysis model in order to quantitatively assess the characteristics of the short/long-term changes in watershed. It supports the effective design of water cycle improvement facilities by supplementing the strengths and weaknesses of existing conceptual parameter-based lumped hydrologic models and physical parameter-based distributed hydrologic models. The CAT especially supports the analysis of runoff processes in paddy fields and reservoirs. To evaluate the impact of agricultural reservoir operation and irrigation water supply on long-term rainfall-runoff process, the CAT was applied to Idong experimental catchment, operated for research on the rural catchment characteristics and accumulated long term data by hydrological observation equipments since 2000. From the results of the main control points, Idong, Yongdeok and Misan reservoirs, the daily water levels of those points are consistent well with observed water levels, and the Nash-Sutcliffe model efficiencies were 0.32~0.89 (2001~2007) and correlation coefficients were 0.73~0.98.

• Journal of the military operations research society of Korea
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• v.11 no.1
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• pp.111-129
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• 1985

Markov chains with large transition probability matrices occur in many applications such as manpowr models. Under certain conditions the state space of a stationary discrete parameter finite Markov chain may be partitioned into subsets, each of which may be treated as a single state of a smaller chain that retains the Markov property. Such a chain is said to be 'lumpable' and the resulting lumped chain is a special case of more general functions of Markov chains. There are several reasons why one might wish to lump. First, there may be analytical benefits, including relative simplicity of the reduced model and development of a new model which inherits known or assumed strong properties of the original model (the Markov property). Second, there may be statistical benefits, such as increased robustness of the smaller chain as well as improved estimates of transition probabilities. Finally, the identification of lumps may provide new insights about the process under investigation.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.130-137
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• 2004

A dynamic model of railway reducer is developed by the lumped parameter method. The model accounts for shafts, bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of gear teeth, and bearing life are considered. Excitation forces of railway reduction are considered as the mass unbalance of the rotors, misalignment and a function of gear transmission error which comes from the modified tooth surface. A campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not the critical speed. The program which can be used to analyze and predict vibration/noise characteristics by mass unbalance, misalignment and gear transmission error of railway reduction is developed with this system model.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.322-326
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• 1997

The condensate in a single vertical reflux condenser with a tube of the large L/D ratio could carried over in both ways of fill-and-dump and the annular occurrent to steam flow. From the experimental observation made, a theoretical model based on the lumped parameter method is made to understand the dynamics of the reflux condenser. The present model predicts well the time period of fill-and-dump model and the natural vibrational frequency of the water column. This could be a first step to understand the complex phenomena in the reflux condenser such as itd improved thermal performance due to the well controlled pulsation in steam flow and the tube-to tube effect in the multi tube reflux condenser.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.723-724
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• 2002

Computational modeling is presented to investigate the hemodynamics of coronary circulation for the cardiac arrest model during the operation of an ECLS called T-PLS. A lumped parameter model is utilized to delineate the hemodynamics of coronary circulation. For verification of the present method, we compute the coronary circulation for normal case and compare those results with the existing data. Numerical results on the cardiac arrest model show that T-PLS can increase LAD flow significantly.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.460-463
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• 1995

The present paper studies a robot manipulator's contact tasks on the uncertain flexible objects. The flexible object's distributed parameter model is approximated into a lumped "position state-varying" model. By using the well-known nonlinear feedback compensation, the robot's control space is decomposed into the position control subspace and the object's torque control subspace. The optimal state feedback is designed for the position loop, and the robot's contact force is controlled through controlling the resultant torque on the object using model-reference simple adaptive control. Experiments of a PUMA robot interacting with an aluminum plate show the effectiveness of this control approach. approach.

• Transactions of the Society of Information Storage Systems
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• v.8 no.1
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• pp.22-26
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• 2012

Optical disk drives (ODDs) are subjected to vibrations caused by the high-speed rotation of the optical disk, and these vibrations can be excessive and reduce the read/write performance. Elastic rubber mounts with cushioning materials are often used to minimize these problems. In this paper, the source of vibrations was identified by experimental modal tests and high-speed photography. Structural modifications were made based on a lumped parameter model and a finite element model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.610-616
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• 2008

This paper presents a new robust sensorless control system for high performance induction motor drives fed by a matrix converter with variable structure. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by a variable structure approach based on model reference adaptive scheme. A Reduced Order Extended Luenberger Observer(ROELO) is also employed to bring better responses at the low speed operation. Experimental results are shown to illustrate the performance of the proposed system.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.41-51
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• 1997

A dynamic mathematical model of a thermal power plant with a single drum-type boiler is described with the base on modular concept. The present process model, which is including full scope of the components and high load changes, is based on physical approach through lumped parameters. The module, which means a component of the power plant and must essentially depict the characteristics of the component well, might be interconnected using pressure nodal method in a arrangement determined by users. With the results of the load changes of 75 MW to 95 MW and 95MW to 75 MW with the rate of 3 MW/min, the applicability of the process model is examined connecting to DCS(Dispersion Control System), which has a real running logic of 100 MW real power plant.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.360-368
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• 2008

A lumped parameter model of Li-ion battery in hybrid electric vehicle(HEV) is constructed and system parameters are identified by using recursive least square estimation for different C-rates, SOCs and temperatures. The system characteristics of pole and zero in the frequency domain are analyzed with the parameters obtained from different conditions. The parameterized model of a Li-ion battery indicates highly dependent of temperatures. To estimate SOC and polarization voltage, a Luenberger state observer is utilized. The P- or PI-gains of observer based on a suitable natural frequency and damping ratio is adopted for the state estimation. Satisfactory estimation accuracy of output voltage and SOC is especially obtained by a PI-gain. The feasibility of the proposed estimation method is verified through experiment under the conditions of different C-rates, SOCs and temperatures.