• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.911-914
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• 1995

Measurement and inspection of freeform surface are required in reverse design process. In the case of surface measurement using a touch probe, probe radius compensation affects measuring accuracy But current industrial practice depends upon an operator's experience to compensate for probe radius. In this paper, an on-the-machine measuring and inspection system for freeform surfface was developed. Probe radius compensation methodology was studied via modeling of B-spline surfaces based on digitized data. The accuracy and reliability of the measurement system was confirmed through various kinds of experiments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.216-222
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• 1996

Since many typical 2.5 Gbps optical transmitter modules use a 50$\Omega$ characteristic impedance, they require relatively high voltage and high power sources compared to the 25$\Omega$ module. However, simple replacement of the 50$\Omega$ internal matching impedance with 25$\Omega$ results in bandwidth reduction and consequent problem of data transmitter module is proposed in order to expand the modulator bandwidth. From the calculated resutls based on accurate 3-dimensional inductance analysis, we have found that the series parasitic inductance is a dominant element limiting the bandwidth and the insertion of a 2.5pF capacitor in parallel to the 20$\Omega$ matching resiter can increase the 3 dB bandwidth about 1.4GHz wider. The time-domain results show the rise time (140 psec) without the compensation is greatly improved to 63 psec with the compensation. This capacitive ocmpensation can be implemented easily and be compatible with common manufacturing process of the optical transmitter module.

• 전자공학회논문지 IE
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• v.45 no.3
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• pp.36-41
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• 2008

By considering decoupling between loops as a kind of measurable disturbance, a steady-state decoupling method based on feedforward compensation is proposed for a three-tank liquid level system often encountered in practical process control. In addition, the three-tank liquid level system's dynamic model with structure of two-input and two-output is presented according to its working principle. Finally simulation experiments given in C++Builder language demonstrate the effectiveness of the proposed method.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.172-177
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• 2016

Miller feedback compensation is introduced in a low dropout regulator (LDO) in order to obtain a capacitor-free regulator and improve the fast transient response. The conventional LDO has a limited bandwidth because of the large-size output capacitor and parasitic gate capacitance in the power MOSFET. In order to obtain a stable frequency response without the output capacitor, LDO is designed with resistor-capacitor (R-C) compensation and this is achieved with a connection between the gain-stage and the power MOS. An R-C compensator is suggested to provide a pole and zero to improve the stability. The proposed LDO is designed with the 0.35 μm CMOS process. Simulation testing shows that the phase margin in the Bode plot indicates a stable response, which is over 100^o. In the load regulation, the transient time is within 55 μs when the load current changes from 0.1 to 1 mA.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1472-1481
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• 2001

In this paper, an advanced shift controller that supervises the shift transients with adaptive compensation is presented. Modern shift control systems for vehicle automatic transmission are designe d to provide smooth transients for passengers' comfort and better component durability. In the conventional methods, lots of testing and calibration works have been done to tune gains of the controller, but it does not assure optimum shift quality at all times owing to system variations often caused by uncertainties in shifting hydraulic systems and external disturbances. In the proposed control scheme, an adaptive compensation controller with intelligent supervisor is implemented to achieve improved shift quality over the system variations. The control input pattern which generates clutch pressure commands in hydraulic actuating systems, is updated through a learning process to adjust for each subsequent shift based on continuous monitoring of shifting performance and environmental changes. The proposed algorithm is implemented and evaluated on the experimental test setup. Results from the experimental studies for several operation modes show both improved performance and adaptability of the proposed shift controller to uncertain changes of the shifting environment in vehicle power transmission systems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.15-20
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• 2016

In this study, a numeric model for the prediction of ideal surface roughness in the rounded end mill was derived from the shape of the tool and feed per tooth. The model is compared with the well-known model of a ball and flat end mill. The ideal surface roughness was matched to the actual surface roughness by the linear equation, from which the empirical constant should be gathered from the test machining systems in the industry.

• Journal of the Korean Home Economics Association
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• v.48 no.6
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• pp.133-147
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• 2010

This study aimed to identify the dimensions of successful aging, as perceived by elderly Koreans, and to test qualitatively the elders' optimization of selection and compensation strategies in a social activity context. The results were as follows: First, the most important part of life fulfillment and regret was family and work. Second, social activity played a role in self-actualization and physiological needs. Moreover, it contributed to the elders' physical and mental health maintenance. Third, the elderly effectively participated in social activities by optimizing their selection and compensation strategies. Fourth, the elderly realized they are growing old, but considered it as a natural process. In addition, some participants suggested retirement age should be raised, but others were against this idea. Finally, elders thought successful aging means having a sufficient and independent life in old age. Thus, the elderly required good health, economic security, and a positive attitude for aging successfully.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.54-62
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• 2001

This paper describes a new method for measuring the changes in specific surface asperities arising from processes such as finishing, coating, wear and corrosion. In repetitive measurements, relocation device gives the same position and orientation so that specific profile can be obtained. A low-cost relocation device is designed and its performance is assessed. The error in relocation process is compensated by statistic compensation algorithm. And, a removing process of cusp by grinding is observed by the proposed method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.53-60
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• 2011

In this study, the priority was assessed and the compensation relationships were analyzed with regard to the issue of port development with conflicts among decision makers. First, the assessment factors were selected by the relevant literatures on port development, and fuzzy structure modeling was used to select assessment factors via structuralization analysis. Second, the local residents, port users, and local government were chosen as the main port-development related entities, and the analytic hierarchy process was used to calculate the total assessment value. Third, the justice based on majority power rule method was used as an assessment method that would minimize the amount of complaints according to the total assessment results and the alternative selection when a partnership was formed among the assessment entities. Moreover, the compensation issue according to the alternative selection was quantified, and the compensation relationships were analyzed. As a result, it was found that port development in Busan must be the top priority in terms of port development in South Korea, that awareness of environmental issues must be promoted among the port users, and that the local governments must promote environmental incentive policies for Environment-friendly port development.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.137-142
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• 2013

Speech recognition system is input of inaccurate vocabulary by feature extraction case of recognition by appear result of unrecognized or similar phoneme recognized. Therefore, in this paper, we propose a speech recognition error correction method using phoneme similarity rate and reliability measures based on the characteristics of the phonemes. Phonemes similarity rate was phoneme of learning model obtained used MFCC and LPC feature extraction method, measured with reliability rate. Minimize the error to be unrecognized by measuring the rate of similar phonemes and reliability. Turned out to error speech in the process of speech recognition was error compensation performed. In this paper, the result of applying the proposed system showed a recognition rate of 98.3%, error compensation rate 95.5% in the speech recognition.