• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.623-640
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• 2017

The full nonlinear equations of an unmanned aerial vehicle ground taxiing mathematical dynamic model are built based on a type of unmanned aerial vehicle data in LMS Virtual.Lab Motion. The flexible landing gear model is considered to make the aircraft ground motion more accurate. The electric braking control system is established in MATLAB/Simulink and the experiment of it verifies that the electric braking model with the pressure sensor is fitted well with the actual braking mechanism and it ensures the braking response speediness. The direction rectification control law combining the differential brake and the rudder with 30% anti-skid brake is built to improve the directional stability. Two other rectifying control laws are demonstrated to compare with the designed control law to verify that the designed control is of high directional stability and high braking efficiency. The lateral displacement increases by 445.45% with poor rectification performance under the only rudder rectifying control relative to the designed control law. The braking distance rises by 36m and the braking frequency increases by 85.71% under the control law without anti-skid brake. Different landing conditions are simulated to verify the good robustness of the designed rectifying control.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.419-424
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• 2010

Through the process of state estimation in the electric railway substation, this paper presents a new method for improving the reliability of the measurements corrupted by gauge error. Unlike the case of commercial power systems, it has been difficult to perform the state estimation by using the usual methods in the electric railway substation. At some of the monitoring points in the substation, most often, it is hard to define the measurement functions by use of the states or as we set up a new states set with the change of system topology, some of the measurement functions become part of the states themselves, which leads to poor results. To resolve the problems in the existing method caused by the relations between the states and the measurement functions at the monitoring points, the proposed method in this paper exploits the equality constraints. They can be derived numerously and concisely from the current and the voltage attributes of the Scott transformer and the buses connecting conditions, etc. We have proofed the effectiveness of the proposed method by the test on a standard sample substation.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.297-305
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• 1996

In this paper a novel robust adaptive fuzzy controller for the nonlinear system with state-dependent uncertainty is proposed. The conventional adaptive fuzzy controller determines the function of state variable bounding the state-dependent uncertain term in the system dynamics on the local state space by off-line calculation. Whereas the proposed method determines that function by the fuzzy inference so that it guarantees the stability of the closed loop system globally on the whole state space. In addition, the method is applicable to the multi-input system. We applied the proposed method to the Burn Control of the Tokamak fusion reactor whose dynamics contains the state-dependent uncertainty and proved the effectiveness of the scheme by using the simulation results.

• Journal of applied mathematics & informatics
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• v.39 no.5_6
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• pp.851-858
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• 2021

In general, secondary batteries are widely used as an electric energy source. Among them, the state of energy storage of mobile devices is very important information. As a method of estimating a state, there is a method of estimating the state by integrating the current according to an energy storage state of a battery, and a method of designing a state estimator by measuring a voltage and estimating a charge amount based on a battery model. In this study, we designed the state estimator using an extended Kalman filter to increase the precision of the state estimation of the charge amount by including the error of the system model and having the robustness to the noise.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.115-123
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• 2012

As the market of lithium secondary batteries moves from mobile IT devices to large-format electric vehicles or energy storage systems, the strengthened battery specifications such as long-term reliability longer than 10 years, pack-level safety and tough competitive price have been required. Moreover, even though high power properties should also be achieved for hybrid electric vehicles, it is not easy to measure accurate power values at various conditions. Because it is difficult to choose a proper measurement method and its experimental condition is more complex comparing to capacity measurement. In addition, the power values are very sensitive to power duration time, state-of-charge (SOC) of cells, cut-off voltages, and temperatures, whereas capacity values are not. In this paper, we introduce three kinds of power measurement methods, hybrid pulse power characterization (HPPC) suggested by US FreedomCar, so-called J-pulse by Japan electric vehicle association standards (JEVS) and constant power measurement, respectively. Moreover, with pouch-type unit cells for HEV, experimental power data are discussed in order to compare each power measurement.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.191-192
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• 2002

We reported pushing of colloidal particles by a moving isotropic-nematic phase boundary. Here, we report tailoring the structure of 3-dimensional networks formed by these particles by adjusting the rate of phase transition and by application of an electric field. The resulting networks affect the electro-optic performance of liquid crystal devices.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.9
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• pp.364-371
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• 1984

This paper describes a method for the state estimation in electric power system. The state values are estimated through the weighted least square method considering the bad data. Then, the bad data are identified by using sensitivity coefficients of power system after being detected the bad data through the distribution of T. This method was applied to the model power system, and, the results of test for proposed method are given.

• International Journal of Automotive Technology
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• v.2 no.4
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• pp.157-164
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• 2001

The vehicle electric power system, which consists of two major components: a generator and a battery, which have to provide numerous electrical and electronic systems with enough electrical energy. A detailed understanding of the characteristics of the electric power system, electrical load demands, and the driving environment such as road, season, and vehicle weight is required when the capacities of the generator and the battery are to be determined for a vehicle. An easy-to-use and inexpensive simulation program may be needed to avoid the over/under design problem of the electric power system. A vehicle electric power simulator is developed in this study. The simulator can be utilized to determine the optimal capacities of generators and batteries. To improve the expandability and easy usage of the simulation program, the program is organized in modular structures, and is run on a PC. Empirical electrical models of various generators and batteries, and the structure of the simulation program are presented. For executing the vehicle electric power simulator, data of engine speed profile and electric loads of a vehicle are required, and these data are obtained from real driving conditions. In order to improve the accuracy of the simulator, numerous driving data of a vehicle are logged and analyzed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2140_2141
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• 2009

We used the eddy current sensor for a 22.9kV distribution power line insulation cable diagnosis. The insulation cable which is used in the 22.9kV distribution power line is having element wire from 6 to 18. Consequently, currently to ECT applications it has a limit in the distribution power line. We about under producing to apply in pick-up coil forms and the differential total coil form where becomes sum of zero in order to have. From measurement result, partial broken cable was confirmed 500 mV~980 mV changes from normal state.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.72-77
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• 2000

This paper presents the results of the application of a computational fluid dynamics algorithm for the simulation of plasma flows of arc-heated jet. The underlying physical model is based on the axisymmetric form of the conservation equations that are coupled with an arc model including Ohm heating, electromagnetic forces. The arc model given as a source term in fluid dynamic equations is determined by a solution of electric potential field governed by an elliptic partial differential equation. The governing equation of electric field is loosely coupled with fluid dynamic equations by an electric conductivity that is a function of state variables. However, the electric fields and flow fields cannot be solved In fully coupled manner, but should be solved iteratively due to the different characteristics of governing equations. With this solution approach, several applications of arc flow analysis will be presented including Arc Thruster and Circuit Breaker.