• Journal of Power System Engineering
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• v.4 no.2
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• pp.58-64
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• 2000

A method for the position control of a pneumatic cylinder using a linearized controller is proposed. Pneumatic cylinder has highly nonlinear characteristics and modelling of the system has been difficult. Compliance of the pneumatic cylinder is materially changed according to the operating position. So, in the case that fixed gain controller obtained by a linearized model at a specified position is used, response of the cylinder should be changed according to the operating position. In order to get a designed results regardless of operating positions, a controller for compensation of the nonlinear characteristic with a linearlization compensator is designed and simulation results show that this method is appropriate for the control object.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.1-11
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• 2011

The main objective of this paper is to investigate characteristic of steam reformer at various geometries and operating conditions. In this paper, the steam reforming is studied by a numerical method and three dimensional simulations were used for effective analytical study. User - Defined Function (UDF) was used to simultaneously calculate reforming and combustion reaction. And the numerical model is validated with experimental results at the same operating conditions. In order to understand the relationship between operating conditions such as gas hourly space velocity(GHSV), mass flow rate of combustor inlet, various numerical investigations are carries out for various geometries. Numerical results show that cylindrical geometry is more effective than rectangular geometry for heat transfer to reactors and reforming efficiency. As mass flow rate of combustor inlet increase, reaction occurs more faster and temperature increase with each geometry. On the other hand, reaction and hydrogen conversion decrease as mass flow rate of reactor decreases.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.3
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• pp.263-267
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• 2005

Building classifiers for financial real-world classification problems is often plagued by severely overlapping and highly skewed class distribution. New performance measures such as receiver operating characteristic (ROC) curve and area under ROC curve (AUC) have been recently introduced in evaluating and building classifiers for those kind of problems. They are, however, in-effective to evaluation of classifier's discrimination performance in a particular class of the classification problems that interests lie in only a local operating range of the classifier, In this paper, a new method is proposed that enables us to directly improve classifier's discrimination performance at a desired local operating range by defining and optimizing a partial area under ROC curve or domain-specific curve, which is difficult to achieve with conventional classification accuracy based learning methods. The effectiveness of the proposed approach is demonstrated in terms of fraud detection capability in a real-world fraud detection problem compared with the MSE-based approach.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.3
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• pp.191-198
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• 2002

Cooling tower design procedure was set up using conventional Merkel theory, The design data could be different depending on the characteristic curve that the engineer chose. It reveals that the consistent and reasonable criteria are required based on the exact information of the cooling tower Performance. In this study, an off-design performance analysis program for a counterflow-type cooling tower was developed and verified by comparing with experimental data. Also, the off-design performance with various operating conditions was analyzed.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.191-193
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• 1999

The various advantages of DSPSRM lie in constructional simplicity, robustness and low cost. Also it has a specific characteristic of axial flux machine and radial flux machine simultaneously. In this paper, we designed and manufactured its operating drive and measured the characteristics of torque, efficiency, current to speed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.51-55
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• 1992

By using the state plane approach, the steady state analysis and design of a half bridge parallel-series (LLC-type) resonant converter (HBPSRC) operating in the continous conduction made is presented. The state-plane diagram representation of the converter response gives good insight into the converter operation. Based on this analysis, a set of steady state characteristic waves for HBPSRC is presented. A simple design procedure is given and design example for a 100watts, 30KHz HBPSRC is presented for illustrative purposes.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.597-600
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• 1996

This study has compared the two types of systems which measure the temperature of coal powder in feeder lines of boiler and analyzed operating data. We used RTD(Resistance Temperature Detector) and optic sensors to measure the temperature. From the characteristic comparison of data, field test and system operation, we confirm that the latter is more efficient than the former.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.332-336
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• 1989

This paper describes the nonlinear analysis and effectual operation methods of thermal power plant turbine control system. When the turbine control governor system has dead-zone characteristic, the effectual frequency development control is difficult, because turbine output does not correspond to frequency deviation in dead-zone. Therefore to obtain effectual correspondance, the turbine dead-zone characteristic must be analyzed by proper method. This paper proposes this nonlinear analysis and effectual plant operating load.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.284-291
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• 2006

Recently with the motorizing of electric home appliances and car systems, there is increasing interest in high efficiency electric motors. Thus, the present study described the operating characteristics of coreless AFPM motor that is highly efficient in high speed driving, and discussed its electric characteristics from the perspective of design. In particular, we examined back electromotive force and the magnetic field characteristic in slits, which have significant effects on the characteristic of the motor, and conducted simulation and experiment on control characteristic according to inductance characteristic. This study analyzed torque speed and efficient operation characteristic as well as control characteristic through comparing the result of motor design with the result of output characteristic experiment based on the electric network method. Furthermore, we evaluated vibration and noise that may occur due to the absence of core.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.138-143
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• 2018

In general, the operating temperature of electronic equipment is closely related to product life and reliability, and it is recognized that effectively cooling the parts is an important problem. In this paper, an experimental study on the cooling characteristic according to the pin array of the heat sink is conducted. The experiment on the heat sink was based on the natural convection and temperature distribution changes. The experimental results indicate that the pin array of the heat sink has an effect on the thermoelectric module's cooling characteristic.