• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.272-279
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• 2005

In this study the optimal isolation system for the prototype HIFD(high impulsive force device) is investigated. For this purpose, firstly, the dynamic behavior of a human body and a transmitted force under specific operation conditions are analyzed through a series of experimental works using the devised test setup. In order to design the optimal dynamic absorbing system, the parameter optimization process is performed using the simplified isolation system model based on the experimental results of linear impulse and transmitted force. Finally, under the parameters satisfying the constraints of the buffering displacement and the transmitted force, the performance of the designed isolation system for the prototype HIFD is evaluated by experiment.

• KSBB Journal
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• v.17 no.4
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• pp.396-402
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• 2002

Biodiesel has attracted considerable attention during the past decade as a biodegradable, nontoxic, and renewable fuel, Several processes for the production of biodiesel have been developed, among which transesterification under alkali-catalysis gives high level yield of methyl esters in short reaction times. In this research, response surface method was applied to optimize the transesterification reaction under alkali-catalysis. It was found that reaction temperature, reaction time, and agitation rate of reactor had profound effects among the seven variables affecting on biodiesel conversion. The optimal temperature, reaction time, and agitation speed were 67$^{\circ}C$, 68 minutes, and 94 rpm, respectively. Under the optimal conditions, the experimental value of biodiesel conversion was 99.7%.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.4
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• pp.95-103
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• 2008

Diamond core drills are applied to drill difficult-to-cut materials. This paper proposes basic understanding of ceramic drilling mechanics and characteristics of main factors affecting tool life, tool wear, cutting force, and chipping thickness. In contrast to conventional drilling, the core drilling process make deep grooves on the workpiece. One difficulty of it is the evacuation of chips from the drilled groove. As the drilling depth increases, an increased amount of chips tend to cluster together and clog the groove. Eventually severe wear develops and diamond grits are separated from the drill body. To relieve the clogging problem and to evacuate chips from the groove easily, the helical drilling process is applied for the core drilling process. To analyze drilling characteristics and derive optimal drilling conditions, tool life, tool wear, cutting force, and chipping thickness are quantified through the monitoring system and the Taguchi method. Mathematical models for the tool life and chipping thickness are derived from the response surface method. Optimal drilling database has been constructed through the experimental models.

• Journal of Multimedia Information System
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• v.5 no.2
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• pp.91-98
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• 2018

We devised a bird-borne transceiver unit for S-band packet radio communications based on the CC2500 transceiver, a device manufactured by Texas Instruments (TI). Our assessments determined the optimal parameters needed to achieve successful bird-to-center communication over a distance of 18 km and bird-to-bird communication over a distance of 200 m. These parameters included optimal modulation methods, transmission rates, and antennas. We equipped the transceiver unit with a modified dipole antenna (collinear antenna), which we tested in a 10 m anechoic chamber. Our experimental assessments and circuit design review identified the following parameters: 2FSK modulation method; 14.28 kHz frequency shift; 101.56 kHz IF reception bandwidth; and Manchester encoding (+). Our assessments showed bird-to-bird communications could be achieved over a distance of 200 m assuming MSK, FEC (+), and 500 kbps. Following tests by an official body, we obtained 28 sets of a type approval license for 2.4 GHz. In cooperation with the Yamashina Institute for Ornithology, we attempted to tag and release six or more swans. This unit gives us the ability to obtain vital data on swans. We expect this data to provide significant benefits, including clues on improving screening for infected individuals.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.137-140
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• 2000

We provide an useful method to design codebooks with better performance than conventional methods. In the proposed method, new codevectors obtained by learning iterations are not the centroid vectors which is the representatives of partitions, but the vectors manipulated by the distance between new codevectors and old codevectors in the early stages of learning iteration. Experimental results show that the codevectors in the obtained by the proposed method converge to a better locally optimal codebook.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.41
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• pp.25-31
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• 1997

A study to analyze and solve problems of a biochemical process experiment has presented in this paper. We have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.539-544
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• 1998

This paper presents the stabilization of a shipboard satellite antenna system. Hardware systems composing the pedestal, pedestal control unit and antenna control unit are designed and stabilization control law is obtained. A model on each control axis is derived and its parameters are estimated using a genetic algorithm, and the optimal state controller is designed based on the estimated model. An experimental result demonstrates the effectiveness of the proposed system.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.1
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• pp.27-38
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• 1994

Accumulation analysis is difficult to analyze the ordered categorical data except smaller-the-better type problem. The purpose of this paper is to develop the statistic and method that can be easily applied to general type of problem, including nominal-the-best type problem. The experimental data of contact window process is analyzed and new procedure is compared with accumulation analysis.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.254-257
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• 1989

In general, unstable phenomena of induction motor are oftenly appeared at low speed and light load. This paper discribes eigenic unstable regions of I.M. itself by computer simulations and the results are compared to experimental ones. And also the optimal design parameters of I.M. which the unstable reg ion can be minimized are determined.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.58-62
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• 1996

In case of hard turning, tool wear is acclerated by heat. So we intend to decrease tool wear by using an air-jet cooling system. Before constructing the air-jet cooling system, no chipping conditions were selected through a statistical method, so called 'Taguchi method', and then the air-jet cooling system was developed by synthesizing and analyzing the results of experimental data through Taguchi method. The air-jet cooling system actually reduced flank wear of TiN coated tool by 25%.