• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1344-1350
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• 1990

A design method of ultra-broadband microwave amplifier is presented. A lossy network is represented as the combination of a serial impedance component and a parallel admittance component, and the realizable ranges of the gain and the reflection coefficients are derived with the components connected to the input, output or interstage network. The matching network has been designed by using the serial and parallel immittance loci which have the constant gain or reflection coefficients within the realizable ranges. Using the proposed method, deisgn examples of ultra-broadband amplifiers operating from dc to 12GHz frequency range are presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.368-374
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• 2008

Multi-axial simulation table(MAST) is widely used in motor companies as the multi-axial excitor for vibration fatigue of target component, which provides the vibrational condition as close as the vehicle test. However, the vibration fatigue performance of target component can be guaranteed with MAST system only in case the input profile covers the required severity of the target component on field test. In this paper, the signal processing for multi-axial vibration fatigue test on vehicle component is presented, from the data acquisition of the target component to the derivation of input profile. To compare the severity of vibration condition between field and proving ground, the energy principle of a equivalent damage is proposed and then, it is determined the optimal combination of special events on proving ground using a sequential searching optimal algorithm. To explain the vibration methodology clearly, seat and door component of vehicle are selected as a example.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.330-337
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• 2016

In this paper, component sizing and analysis of the novel plug-in hybrid electric vehicle powertrain configuration is conducted. Newly proposed powertrain configuration in prior study has an internal combustion engine and two electric motors. To optimize component size of the vehicle system and reduction gear ratio, component sizing methodology is proposed and conducted. Required power for vehicle's dynamic performance is calculated to decide minimum power requirement of powertrain component combination. Component size of engine and electric motor are optimized using vehicle simulation to maximize fuel economy performance. Optimized powertrain configuration and vehicle simulation results present validation of newly proposed vehicle system.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.11
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• pp.1089-1095
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• 2010

We propose an image segmentation method for auto-teaching system of PCB (Printed Circuit Board) assembly inspection machines. The inspection machine acquires images of all components in PCB, and then compares each image with its standard image to find the assembly errors such as misalignment, inverse polarity, and tombstone. The component window that is the area of component to be acquired by camera, is one of the teaching data for operating the inspection machines. To reduce the teaching time of the machine, we newly develop the image processing method to extract the component window automatically from the image of PCB. The proposed method segments the component window by excluding the soldering parts as well as board background. We binarize the input image by use of HSI color model because it is difficult to discriminate the RGB colors between components and backgrounds. The linear combination of the binarized images then enhances the component window from the background. By use of the horizontal and vertical projection of histogram, we finally obtain the component widow. The experimental results are presented to verify the usefulness of the proposed method.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4E
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• pp.156-163
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• 2002

We apply independent component analysis (ICA) for extracting an optimal basis to the problem of finding efficient features for representing speech signals of a given speaker The speech segments are assumed to be generated by a linear combination of the basis functions, thus the distribution of speech segments of a speaker is modeled by adapting the basis functions so that each source component is statistically independent. The learned basis functions are oriented and localized in both space and frequency, bearing a resemblance to Gabor wavelets. These features are speaker dependent characteristics and to assess their efficiency we performed speaker identification experiments and compared our results with the conventional Fourier-basis. Our results show that the proposed method is more efficient than the conventional Fourier-based features in that they can obtain a higher speaker identification rate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.60-67
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• 2000

An improved disturbance rejection control scheme is presented for minimizing the position error due to the repeatable runout disturbances in high density disk drive systems The proposed control algorithm is capable of attenuating repeatable disturbances which is one of the major detractors to hard disk drive quality and performance. This is achieved by a sys-tematic combination of an optimal feedback component and a feedforward preview component. The feedback component is designed where the emphasis is placed on robustness. The feedforward component is on the basis of a preview control comprised of a measured disturbance signals which leads to better disturbance rejection capabilites. The designed con-troller is applied as a plug-in module to a high density hard disk drive with a pre-existing conventional servo controller. Simulations have been carried out to demonstrate the effectiveness of this control scheme in the reduction of the periodic disturbances.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1091-1110
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• 2016

Hybrid deployment under current cloud data centers is a combination of online and offline services, which improves the utilization of the cluster resources. However, the performance of the cluster is often affected by the online services in the hybrid deployment environment. To improve the response time of online service (e.g. search engine), an effective scheduling algorithm based on Storm is proposed. At the component level, the algorithm dispatches the component with more influence to the optimal performance node. Inside the component, a reasonable resource allocation strategy is used. By searching the compressed index first and then filtering the complete index, the execution speed of the component is improved with similar accuracy. Experiments show that our algorithm can guarantee search accuracy of 95.94%, while increasing the response speed by 68.03%.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.156-156
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• 2002

We apply independent component analysis (ICA) for extracting an optimal basis to the problem of finding efficient features for representing speech signals of a given speaker The speech segments are assumed to be generated by a linear combination of the basis functions, thus the distribution of speech segments of a speaker is modeled by adapting the basis functions so that each source component is statistically independent. The learned basis functions are oriented and localized in both space and frequency, bearing a resemblance to Gabor wavelets. These features are speaker dependent characteristics and to assess their efficiency we performed speaker identification experiments and compared our results with the conventional Fourier-basis. Our results show that the proposed method is more efficient than the conventional Fourier-based features in that they can obtain a higher speaker identification rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.163-169
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• 2009

The research performed a test concerning the fluidity and strength of concrete manufactured by combining lime stone power, fly ash, and blast furnace slag into two and three component systems, aiming at evaluating rheological and dynamic properties of concrete by manufacturing High Flowing Self-Compacting according to the strength changes of three levels. As a result of the research, for High Flowing Self-Compacting of 30 MPa, the combination of lime stone power 20% and fly ash 30% for securing quality and strength and adjusting viscosity satisfied the required performance. For High Flowing Self-Compacting of 50 MPa, the combination of blast furnace slag 10% and fly ash 20% satisfied the fluidity and strength of the requirement performance. Also, for 70 MPa that has many power contents, the combination of blast furnace slag 20% and fly ash 10% for the increase of fluidity and the reduction of viscosity satisfied the required performance. It is judged that fly ash in all combinations can be used to secure viscosity and reduce concrete amount. In addition, it is judged that for High Flowing Self-Compacting according to the levels of compressive strength the combination of three component system including fly ash is more appropriate than the combination of two component system.

• YAKHAK HOEJI
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• v.53 no.5
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• pp.241-249
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• 2009

Various neurotransmitters are involved in regulating stress systems. In this study, we investigated the combination relieving effect of green tea extract(GTE) and L-theanine on the stress induced by electric foot shock. Four week oral administration of GTE (24 mg/kg), L-theanine (4 mg/kg) or their combination reduced the levels of dopamine, noradrenaline and corticosterone in blood, brain cortex, hippocampus, and striatum, wherease increased serotonin level. The combination of GTE and L-theanine showed much greater effects than single treatment of each component, and the effects are comparable to diazepam (2 mg/kg). Therefore, this study suggests that the combination of GTE and L-theanine may act effective and be useful for stress relieving treatment.