• Journal of Music and Human Behavior
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• v.16 no.1
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• pp.73-88
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• 2019

This research was conducted to compare the rhythm reproduction abilities between older adults with and without mild cognitive impairment (MCI) and analyze the abilities depending on the rhythm idiom. Participants between 60-85 years of age were recruited from senior community centers, dementia prevention centers, and senior welfare centers. A total of 57 participants were included in this study: 27 diagnosed with MCI and 30 healthy older adults (HOA). The experiment was conducted individually in a private room in which a participant was given random binary time rhythm idioms and instructed to reproduce the rhythmic idioms with finger tapping. Each participant's beat production was recorded with the Beat Processing Device (BPD) for iPad. BPD calculated rhythm reproduction as measured through rhythm ratio and error among beats. Results showed marginal differences between the two groups in terms of mean scores of rhythm reproduction abilities. In terms of the rhythm ratio among beats, both groups' highest rhythm reproduction rate was for <♩ ♩>, and their lowest reproduction rate was for <♩. ♪>. In conclusion, there was no significant difference in rhythm reproduction ability between the HOA and MCI groups. However, the study found an interesting result related to performance level of rhythmic idioms. This result provides therapeutic insight for formulating rhythm tasks for older adults.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.215-222
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• 2020

The aim of this study was to develop a mobile application 'Beat Processing Device (BPD)' to record and quantify the data for the performance accuracy of rhythm production. BPD has been developed in three phases. First, we reviewed studies that used rhythm as main intervention strategy to improve cognitive functioning of older adults, and derived four basic rhythm idioms. Second, we developed an iOS-based mobile application, optimized the device, the instrument tone, and the measurement variables through preliminary test. Lastly, we tested the mobile application by comparing the performance data obtained from MIDI and BPD from 60 older adults. The device was shown to be reliable and consistent with other mode of measurement and analysis. Conclusively, BPD can be a useful tool for assessing rhythm production ability in the course of cognitive skills training.

• Journal of Music and Human Behavior
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• v.13 no.1
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• pp.1-18
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• 2016

This study examined the correlation between the rhythm reproduction performance and cognitive function of school-aged children. A total of 59 third grade elementary students participated in this study. An iPad-based rhythm reproduction task, the Digit Span Test (DST), the Children's Color Trails Test (CCTT), and a self-paced tapping task via a MIDI keyboard were conducted for each participant. The results demonstrated that scores at each stage of the iPad-based rhythm reproduction test showed different patterns of correlation with cognitive function test scores. This result suggests that accuracy of a simple rhythm task is correlated to speed of self-paced tapping (second). Also cognitive function may affect rhythm grouping ability. Results of this analysis for each of 20 rhythm items showed that there was a common rhythm characteristics that correlated with executive function, working memory or self-paced tapping speed. These results indicate that rhythm ability is related to, and predictive of, the level of cognitive functioning in elementary school students and can be used as an useful parameter when examining cognitive function of school-aged children in multifaceted dimensions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.3
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• pp.311-319
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• 2003

This paper aims at investigating the exact dynamic response of the system undergoing a exponential impact force from the viewpoints of conservations of momentum and energy. The midpoint method applied in the Newmark's family algorithm is found to be identical to the case of the application of the trapezoidal method which provides conservations of momentum and energy. For the linear impact force the mid point, the trapezoidal and the (n+1) point method exactly meet the conservation characteristics independent of the size of integration interval. On the other hand, constants for the dynamic motion resulting from the nonlinear impact are underestimated or overestimated by these method mentioned above. To overcome this indispensible error, the Simpson 1/3 method as one of multi step methods whose advantages is to use longer time interval with the same number of evaluation functions is adopted for the exact conservations of momentum and energy. Moreover, the suggested method is expected to expand the similar algorithm for the general dynamic motion including finite rotations.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.157-164
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• 2007

In this paper, a novel sensorless drive for brushless DC (BLDC) motor using the fuzzy back-EMF observer is proposed to improve the performance of conventional sensorless drive methods. Existing sensorless drive methods of the BLDC motor have low performance at transients or low speed range and occasionally require additional circuits. To cope with these problems, the back-EMF of the BLDC motor must be precisely estimated by a fuzzy logic, which is suitable to estimate the back-EMF which has a trapezoidal shape. The proposed algorithm using fuzzy back-EMF observer can achieve robust control for the change of an external condition and continuously estimate position of the rotor at transients as well as at steady state. The superiority of the proposed algorithm is proved through the simulation compared with other sensorless drive methods.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.123-129
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• 2000

This paper addresses a new double detection algorithm which is based on the fuzzy control in the adaptive echo canceller of communication system. In this method, the two input of the fuzzy inference for detecting double talk condition are used. The one is the cross-correlation coefficient between the error signal and the primary signal which is the summed signal of the real echo signal and the near-end signal. The other is the cross-correlation coefficient between the estimation error signal and the primary signal. The fuzzy controller made a fuzzification for two inputs by the membership functions of trapezoid and them became the composition using inference rules. The composed result is defuzzificated by the center gravity method. The output is compared with two threshold values to detect double talk and echo path variation effectively. It is confirmed by computer simulation that this fuzzy double talk detector is able to track echo path variation accurately.

• The Journal of the Acoustical Society of Korea
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• v.19 no.7
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• pp.34-41
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• 2000

This paper proposes a new double-talk detection algorithm which is based on the fuzzy rules, in the adaptive echo canceller of telecommunication system. In this method, the two inputs of the fuzzy inference for detecting double-talk condition are used. One is the cross-correlation coefficient between the error signal and the primary signal which is the summation of the real echo signal and the near-end signal. The other one is the cross-correlation coefficient between the estimation error signal and the primary signal. The fuzzy controller makes a fuzzification for two inputs by the membership functions of trapezoid does the max-min composition using if-then rules. The composed result is defuzzificated by the center gravity method. And by defuzzificated values, the double-talt the echo path variance, and the echo path variance during the double-talk are detected. It is confirmed by computer simulation that this fuzzy double-talk detector is able to estimate the double talk and the echo path variation condition, and even track echo path variation more accurately than the conventional algorithm during the double-talk period.