• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.723-733
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• 2020

The study investigates the effects of online instructional facilitator's qualities on student performance of online class activities. The study explores the roles of instructional facilitators who may influence student performance of online class activities and their academic achievement. The study employs a set of aggregated data from 1,362 subjects and 10 facilitators who participated in multiple online classes. The results of independent samples t-test reveal that the student performance in online classes has no association with facilitators' educational background or academic degree, as well as demographic characteristics, student evaluation records and instructional achievement. The results of multiple regression analysis show that the facilitator engagement has a positive relation to the enhancement of student interaction, reading discussion messages, and the quality of discussion messages in online discussions. The results of correlation analysis show that the facilitator engagement has a positive impact on both increasing the number of reading discussion messages and enhancing the quality of discussion messages. The facilitator engagement increases the quantity of reading discussion postings and enhances the quality of discussion messages, which would be a substantial contribution to student performance by facilitators. The findings suggest that student performance and academic achievement in online classes are not independent of facilitator engagement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.812-816
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• 1987

A quadratic regulator problem for a class of nonlinear system, in which a small parameter multiplies the control cost, is considered. In the analysis of the problem, we utilize the method of multiple time-scale decomposition which has been devised for analyzing complex linear cheap control problems. In so doing, we extend the class of nonlinear systems, considerably, for which the minimum cost becomes zero as the small parameter goes to zero.

• 대한수학회지
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• 제50권6호
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• pp.1257-1269
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• 2013

Using the three critical points theorem by B. Ricceri [23], we obtain a multiplicity result for a class of nonlocal problems in Orlicz-Sobolev spaces. To our knowledge, this is the first contribution to the study of nonlocal problems in this class of functional spaces.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.220-225
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• 2018

A class E power oscillator is demonstrated for 6.78-MHz wireless power transfer system. The oscillator is designed with a class E power amplifier to use an LC feedback network with a high-Q inductor between the input and the output. Multiple capacitors are used to minimize the variation of the oscillation frequency by capacitance tolerance. The gate and drain bias voltages with opposite characteristics to make the frequency shift of the oscillator are connected in a resistance distribution circuit located at the output of the low drop-out regulator and supplied bias voltages for class E operation. The measured output of the class E power oscillator, realized using the co-simulation, shows 9.2 W transmitted power, 6.98 MHz frequency and 86.5% transmission efficiency at the condition with 20 V $V_{DS}$ and 2.4 V $V_{GS}$.

• 대한음성학회지:말소리
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• 제60호
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• pp.145-164
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• 2006

This paper proposes class histogram equalization (CHEQ) to compensate noisy acoustic features for robust speech recognition. CHEQ aims to compensate for the acoustic mismatch between training and test speech recognition environments as well as to reduce the limitations of the conventional histogram equalization (HEQ). In contrast to HEQ, CHEQ adopts multiple class-specific distribution functions for training and test environments and equalizes the features by using their class-specific training and test distributions. According to the class-information extraction methods, CHEQ is further classified into two forms such as hard-CHEQ based on vector quantization and soft-CHEQ using the Gaussian mixture model. Experiments on the Aurora 2 database confirmed the effectiveness of CHEQ by producing a relative word error reduction of 61.17% over the baseline met-cepstral features and that of 19.62% over the conventional HEQ.

• Tribology and Lubricants
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• 제23권6호
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• pp.312-317
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• 2007

In general, a brake system of axle for heavy duty machine as a wheel excavator makes use of wet-type multiple disk brakes. These disk bakes are very important parts of heavy duty machine because they are advanced in durability and braking power, and can be designed compactly. Thus, we designed and made wet-type multiple disk brakes of axle for the 14ton class wheel excavator to be localization of these imported all. These disk brakes were made a comparative test with the existing disk brakes by the SAE No.2 dynamometer, and the friction characteristics as dynamic and static friction coefficient and wear depth of friction paper were measured.

• 대한수학회지
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• 제31권1호
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• pp.11-28
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• 1994

• ETRI Journal
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• 제28권4호
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• pp.502-505
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• 2006

A new class-based histogram equalization method is proposed for robust speech recognition. The proposed method aims at not only compensating the acoustic mismatch between training and test environments, but also at reducing the discrepancy between the phonetic distributions of training and test speech data. The algorithm utilizes multiple class-specific reference and test cumulative distribution functions, classifies the noisy test features into their corresponding classes, and equalizes the features by using their corresponding class-specific reference and test distributions. Experiments on the Aurora 2 database proved the effectiveness of the proposed method by reducing relative errors by 18.74%, 17.52%, and 23.45% over the conventional histogram equalization method and by 59.43%, 66.00%, and 50.50% over mel-cepstral-based features for test sets A, B, and C, respectively.

• Industrial Engineering and Management Systems
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• 제11권4호
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• pp.331-338
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• 2012

This research proposes a Pareto-based multi-objective optimization approach to class-based storage warehouse design, considering a two-block warehouse that operates under the class-based storage policy in a low-level, picker-to-part and narrow aisle warehousing system. A mathematical model is formulated to determine the number of aisles, the length of aisle and the partial length of each pick aisle to allocate to each product class that minimizes the travel distance and maximizes the usable storage space. A solution approach based on multiple objective particle swarm optimization is proposed to find the Pareto front of the problems. Numerical examples are given to show how to apply the proposed algorithm. The results from the examples show that the proposed algorithm can provide design alternatives to conflicting warehouse design decisions.

• 대한수학회보
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• 제48권1호
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• pp.213-221
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• 2011

In this paper, we establish a multiple critical points theorem for a one-parameter family of non-smooth functionals. The obtained result is then exploited to prove a multiplicity result for a class of periodic eigenvalue problems driven by the p-Laplacian and with a non-smooth potential. Under suitable assumptions, we locate an open subinterval of the eigenvalue.