• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2163-2166
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• 2004

For designing high Tc superconductor proceeding bearing(HTSJB) which is used on a flywheel energy storage system which requests the free of the bearing loss caused by the friction, it is necessary to understand the basic characteristics of the classical superconductor proceeding bearing because the mechanical characteristics of the HTSJB are identified by the magnetic relationships between the permanent magnet(PM) and the high Tc superconductor(HTS). In this paper, using the method, frozen image model, the force problems between the PM and the HTS were solved and then the dynamic characteristics of the rotor inside of the HTSJB can be expected in advance by using the basic characteristics between the PM and the HTS. The coefficient of friction of the HTSJB was measured in the vacuum environment. From the results, the mechanical characteristics of HTSJB can be identified using the numerical models.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.69-77
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• 2006

Photovoltaic is an attractive technology to remote power applications, because of its reliability, low maintenance, and zero fuel requirements. In this paper represents residential PV system based on BESS(battery energy storage system) for managing the electric power, a pattern of daily operation considering the load characteristics of the house, the generation characteristics of PV power, and utility power leveling. For apply to control algorithm, we consider the load on monthly power consumption trend and daily usage pattern. As for the control of the proposed system, to increase the conversion efficiency of the PV power, bidirectional converter is used for MPPT and SPWM inverter. An experimental system is implemented, and some experimental results are provided to demonstrate the effectiveness of the proposed system.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.633-636
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• 2005

An electro-optical camera system consists of many subsystems such as the optics, the detector, and the electronics and so on. They may create variations in the processed image that were not present original scene. The performance analysis of the electro-optical camera system is a mathematical construct that provides an optimum design through appropriate trade off analysis. The SNR(Signal to Noise Ratio) is one of the most important performance for the electro-optical camera system. The SNR analysis shown in this paper is performed based on the practical high resolution satellite camera design. For the purpose of the practical camera design, the analysis assumes that the defined radiance, which is calculated for the Korean peninsula, reached directly to the telescope entrance. In addition, the actual operation concept such as integration time and the normal operation altitude is assumed. This paper compares the SNR analysis results according to the various camera characteristics such as the optics, the detector, and the camera electronics. In detail, the optical characteristics can be split into the focal length, F#, transmittance, and so on. And the system responsivity, the quantum efficiency, the TDI stages, the quantization noise and the analogue noise can be used for the detector and the camera electronics characteristics. Finally this paper suggests the optimum design to apply the practical electro-optical system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.193-199
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• 2011

The next generation domestic high speed railway system is a power distributed type and uses vector control method for motor speed control. Nowadays, inverter driven induction motor system is widely used. However, recently PMSM drives are deeply considered as a alternative candidate instead of an induction motor driven system due to their advantages in efficiency, noise reduction and maintenance. The next-generation high-speed train is composed of 2 converter units, 4 inverter units, and 4 Traction Motor units. Each motor is connected to the inverter directly. In this paper, the effects of IPMSM parameter variation to the system operation characteristics of the multi inverter driven high speed train system are investigated. The parallel connected inverter input-output characteristics are analyzed to the parameter mismatches of the IPMSM in 1C1M control using Matlab/Simulink, then the reliability of the simulation results are verified through experimental results.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1194-1201
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• 2013

This paper introduces a vision-based automatic system (VAMS) for non-contact measurement of morphometric characteristics of flatfish, such as total length (TL), body width (BW), height (H), and weight (W). The H and W are simply measured by a laser displacement and a load cell, respectively. The TL and BW are measured by a proposed morphological image processing algorithm. The proposed algorithm cans measurement, when the tail of flatfish is deformed, and when it is randomly oriented. In the experiment, the average and maximum measurement errors were recorded, and standard deviations and coefficients of variation (CVs) for the measurements were calculated. From those results, when flatfish the TL measurements had an average of 266.844 mm, a standard deviation of 0.351 mm, a CV of 0.131%, and a maximum error of 0.87 mm with straightened flatfish ($TL_A$ : 267 mm, $BW_A$ : 141 mm), and when flatfish of different sizes were measured, the errors in the TL and BW measurements were both about 0.2 %. Using a single conveyor, the VAMS can process up to 900 fishes per hour. Moreover, it can measure morphometric characteristics of flatfish with a TL of up to 500 mm.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2187-2195
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• 2018

In order to realize the multi-objective control of single-input multi-output nonlinear differential algebraic system (NDAS) and to improve the dynamic characteristics and static accuracy, a design method of nonlinear control with multi-objective feedback (NCMOF) is proposed, the principium of this method to arrange system poles, as well as its nature to coordinate dynamic characteristics and static accuracy of the system are analyzed in detail. Through NCMOF design method, the multi-objective control of the system is transformed into linear space, and then it is effectively controlled under the nonlinear feedback control law, the problem to balance all control objectives caused by less input and more output of the system thus is solved. Applying NCMOF design method to generator excitation system, the nonlinear excitation control law with terminal voltage, active power and rotor speed as objective outputs is designed. Simulation results show that NCMOF can not only improve the dynamic characteristics of generator, but also damp the mechanical oscillation of a generator in transient process. Moreover, NCMOF can control the terminal voltage of the generator to the setting value with no static error under typical disturbances.

• Journal of ILASS-Korea
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• v.12 no.2
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• pp.94-100
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• 2007

The liquid phase LPG injection (LPLi) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type (the second generation technology) fuel supply system. To investigate the characteristics of LPG residue in liquid phase LPG injection system, various rubbers in LPG fuel system were reacted with LPG fuels during 3 months. The experimental results showed that the residue of a cover rubber in a fuel pump after test increased 10 times higher than that before test. Furthermore, the amount of sulfur, nitrogen species which are considered as main sources in deposit formation in the LPLi fuel injector were also found to be higher than that in original LPG fuel. And rubber properties of fuel pump cover were decreased after reaction test compared with those of the original rubber. Therefore, the rubber for fuel pump cover is not suitable for a proper material in LPLi fuel system. And these results can provide more information if a motor company shares the data of core rubber parts in field test LPLi vehicles.

• The KSFM Journal of Fluid Machinery
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• v.17 no.4
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• pp.40-46
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• 2014

This paper describes blower performance characteristics of a automated vacuum waste collection system. Blowers serially connected to six or seven centrifugal blowers are evaluated by experimental measurements to understand blower performances according to blower numbers operated. Two different blowers and duct diameters connected to the main blowers are considered. Data acquisition system is introduced to measure pressure and pressure difference at the main duct simultaneously, which is connected to several blowers serially. A auxiliary blower, which is installed between a filter room and an air deodorizing apparatus, is also added to simulate its performance effect on the main blower. Throughout the experimental measurements of the blower system, it is found that pressure and inlet velocity at the upstream of a blower increase 3.7 and 2.4 times separately by increasing the operating blower numbers from one to seven. It is noted that blower efficiency and pressure measured at the system vary according to the distance between a air intake and a blower system. Auxiliary blower is effective to increase blower inlet suction pressure, while total energy consumption is increased relatively.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.42-50
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• 2014

The main object of this study is to investigate the collection characteristics of wet-type multi-layered and multi-staged porous plate system experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as water spray, inlet velocity, stage number and inlet particle concentration, etc. In results, for the present system of wet-type, the pressure drop represents 158 $mmH_2O$ higher 3% than that in dry-type at 5 stage and $v_{in}$=3.53 m/s. In case of 5 stage, $v_{in}$=3.53 m/s and water spray 250 ml/min, the collection efficiency of the present system becomes significantly higher as 99.7% comparing to that of the conventional wet-type scrubber. Additionally, for 5 stage and 250 ml/min, $SO_2$ removal efficiencies decrease with the increment of inlet velocity representing 75.0, 62.5, 50.0%, at $v_{in}$=2.12, 2.82, 3.53 m/s, respectively.

• Journal of the Korean Society of Food Culture
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• v.31 no.5
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• pp.506-514
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• 2016

The objective of this study was to investigate the effect of sample presenting types on the sensory characteristics of chilled buckwheat noodle soup (Naeng-myeon). Generic descriptive analysis was performed for evaluating only stock (system 1), only noodle (system 2) and stock with noodle (system 3). Eight kinds of commercially available Naeng-myeon were samples of interest. Ten female descriptive panelists participated. ANOVA and regression analysis were used for data analysis. In the training sessions, ten sensory properties were developed for system 1, four were additionally established for noodle. In each system, the 8 products showed significantly different intensities in almost all sensory attributes like darkness of stock, overall flavor, sweetness, saltiness, sourness. When integrating the two systems, sample presenting types showed significant difference for the seven sensory attributes, especially saltiness, sourness, beef flavor tended to be rated more strongly in system 1 than system 3.