• Proceedings of the ESK Conference
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• 1996.10a
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• pp.191-196
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• 1996

This paper presents an experimental study of the relationship between sound parameters of synthesized voice warning and perceived(psychoacoustic) urgency. Eighteen subjects participated in two experimental sessions to evaluate and quqntify the effects of the voice parameters. Experiments showed that speech rate, fundamental frequency and voice types have clear and consistent effect on perceived urgency. The results of these experiments can be applied to the improvement of existing auditory warning systems and the design of new systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.45-48
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• 1996

The most research on facility layout problems ignored the actual shape of building where the activities(departments) are to be arranged. They also ignored the aisles between departments inside the building. In this paper, we present a genetic algorithm that searches a very good facility layout with horizontal aisles for two different cases with respect to the department shape. From the extensive experiments, the proposed genetic algorithm generated better layouts than the ones obtained by applying Tam's algorithm. It showed about 10% improvement of performance. We found out the best combination of genetic operators through the experiments.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.339-345
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• 1997

This paper presents an experimental study of te relationship between sound parameters of synthesized voice warning and perceived (psychoacoustic) urgency. Twenty four subjcts participated in two experimental sessions to evaluate and quantify the effects of te voice parameters. Experiments showed that speech rate, fundamental frequency, fundamental frequency contour types and voice types have clear and consistent effect on perceived urgency. The results of these experiments can be applied to the improvement of existing auditory warning systems and the design of new systems.

• MALSORI
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• no.62
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• pp.149-161
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• 2007

In this paper we proposed a modified reliability function for improving bimodal speaker identification(BSI) performance. The convectional reliability function, used by N. Fox[1], is extended by introducing an optimization factor. We evaluated the proposed method in BSI domain. A BSI system was implemented based on GMM and it was tested using VidTIMIT database. Through speaker identification experiments we verified the usefulness of our proposed method. The experiments showed the improved performance, i.e., the reduction of error rate by 39%.

• The Journal of the Acoustical Society of Korea
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• v.4 no.1
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• pp.16-21
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• 1985

Both shifiting the input signal's frequencies by a fixed frequency and compressing the input signal's bandwidth have been known to be effective in improving the stability margin of public adress systems operating in reverberant spaces. This paper describes the effect of an alternative approach of improving the acoustic-feedback stability and yet maintaining speech inteligibility by bandwidth compression and expansion. Conditions are derived for this technizue to be realized and an experimental system has been made - up. A series of experiments has been performed in small spaces and the results have shown that more than 5dB improvement can be obtained in the stability margin.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.37-43
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• 2003

A faster autofocusing method is proposed. The searching speed of microscope camera is limited by the long focusing time due to too much sampled digital image data. The improvement of autofocusing speed based on the down sampling is discussed analytically and is proved by experiments. The anticipated aliasing is found negligible in shilling rate of focus measure.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.757-767
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• 2002

This study investigated the effects of scientific inquiry experiments emphasizing social interaction on the academic achievement, the ability for science inquiry and the learning motivation of the students. To examine the differences among the classes of scientific inquiry experiments according to the way of organizing small groups, the effects of the group in homogeneous cognitive level and the group in heterogeneous cognitive level were compared. 255 7th-graders were grouped into the treatment group and the control group. After the treatment group received the scientific inquiry experimental lessons emphasizing social interaction and the control group received traditional lessons for one year, academic achievement, ability for scientific inquiry, and learning motivation were examined. These inquiry experiments were composed of four steps which are eliciting, familiarizing, constructing and bridging. And students can interact with peers and teachers through the process of relating observed phenomena to concept, constructing experiment procedure, and eliciting results. The ANCOVA results revealed that there were significant effects of science inquiry experiments emphasizing social interaction on the academic achievement, the ability for scientific inquiry and the learning motivation of the students. The significant academic achievement of the students in most of the cognitive levels, if not all, was found and degree of improvement in the ability for scientific inquiry was lower than that in the academic achievement. Concerning the effects according to the way of organizing small groups, there were significant improvement in academic achievement and learning motivation of the group in homogeneous cognitive level compared to the group in heterogeneous cognitive level. These results indicate that social interaction in learning is important and it has positive influences on the improvement in academic achievement and ability for scientific inquiry of students.

• The Journal of Information Systems
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• v.10 no.2
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• pp.129-150
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• 2001

In this study, we model a decentralized supply chain system which is managed by four types of centers, sequentially located: Retailer, Wholesaler, Distributor, and Factory Each center contributes to enhancing the performance of the supply chain system individually with its own local inventory information. Through experiments which are performed with a programmed simulation (like the MIT beer game), we investigate how the information lead time improvement in each center affects the whole system. And we show that the impact of the lead time improvement in the downstream, like retailers, affects more to the system than the one in the upstream, like factories, in a cost-effective way. Moreover, by using information lead time for each center, we analyze how much the extent of the improvement affects the whole system, especially for the total cost and the order level.

• The Korean Journal of Applied Statistics
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• v.7 no.1
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• pp.83-102
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• 1994

Some optimal designs and data analysis methods based on a Gaussian spatial linear model for computer simulation experiments are considered. For designs of computer experiments, Latin-hypercube designs and some optimal designs are combined. A two-stage computational (2-points exchange and Newton-type) algorithm for finding the optimal Latin-hypercube design is presented. The spatial prediction model which was discussed by Sacks, Welch, Mitchell and Wynn(1989) for computer experiments, is used for analysis of the simulated data. Moreover, a method of contructing sequential (optimal) Latin-hypercube designs is considered. An application of this approach to the quality improvement and optimization of the integrated circuit design via the main-effects plot and the sequential experimental strategy is presented.

• Publications of The Korean Astronomical Society
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• v.25 no.1
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• pp.15-21
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• 2010

We report results of image simulations of the KVN and VLBI experiments of the KVN with several other East Asia VLBI facilities. To investigate their imaging capability a model-generated image of 7 mm SiO maser emission in Mira variables is used. The resulting simulations show that the joint VLBI experiments of the KVN with East Asia VLBI facilities can produce reasonably good images at 7 mm spectral line experiments. However, there are no apparent differences in peak flux densities and images themselves in the simulations among different combinations of these facilities. In addition, the simulated images of observations which include bigger antennas do not show any expected improvement to the image sensitivity. The small variations in the peak flux density and similar image sensitivity, irrespective of different antenna sizes or numbers of baselines used in the simulations, turn out due to a specific characteristic of the adopted model image. Test simulations using another SiO maser image from R Cas observations prove that the participation of bigger antennas in the VLBI experiments does improve image sensitivity. We confirm the need of additional longer baselines in the experiments of the East Asia VLBI facilities to study very compact maser clumps on sub-milliarcsecond scales.