• The Journal of Korean Medicine
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• v.24 no.4
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• pp.92-101
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• 2003

Background ＆ Aims : The aim of this study was to investigate the change of dominant power with observation of gastric myoelectrical activity and its parameter linkage in electrogastrography. Methods : Electrogastrography was performed on a total of 123 subjects (113 patients with functional dyspepsia, 10 healthy controls) for 30 min in fasting state and 50 min in postprandial state. Average myoelectrical activity per frequency and accumulated electrical activity of 5 min duration in each bradygastria, normogastria, and tachygastria were measured at the moment of frequency switchover of slow wave. Assumed parameter linkages were also investigated among dominant frequency, ％ of normal regularity, and dominant power (or power ratio). Results : Average myoelectrical activity per frequency was highest in bradygastria (mean 1.10-1.47 Volt/s), next highest in normogastria (mean 0.50-0.82 Volt/s), and lowest in tachygastria (mean 0.44-0.47 Volt/s). Average accumulated myoelectrical activity was highest in normogastria (mean 114.90-126.29 Volt/ss), next highest in tachygastria (mean 71.02-90.00 Volt/ss), and lowest in bradygastria (mean 12.93-51.94 Volt/ss). Significance of parameter linkages were noted in dominant frequency (p< 0.01) and in ％ of normal regularity (p< 0.01), but not in dominant power in case of frequency shift from bradygastria to normogastria (p=0.376). Conclusion : Dominant power is not a parameter that reflects the gastric myoelectrical activity related with only gastric contraction. Bradygastric dominant power does not follow the inter-parameter linkage of electrogastrography for gastric motility assessment.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.295-300
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• 2021

This study investigated the dominant frequency of the elastic waves from the tensile test. The specimen was rolled with five different rolling degrees (10, 22, 33, 42 and 50%), which was treated subzero. The specimen was rolled at room temperature, which was transformed from austenite to martensite (only α'-martensite). The dominant frequency increased with an increase in the rolling degree regardless of the subzero temperature, and decreased after 33% of the rolling degree. On the other hand, higher frequency band was obtained at lower temperature and long time. The dominant frequency increased when the amount of α'-martensite increased and decreased with the α'-martensite amount between 50-65%. The lower subzero treatment temperature increased the amount of α'-martensite, which resulted in the higher dominant frequency. The longer treatment time at the same subzero temperature led to an increase in the amount of α'-martensite, leading to high dominant frequency.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.325-331
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• 2022

In this study, austenitic 316L stainless steel was rolled at three different temperatures (100℃, -50℃, -196℃) at five rolling degree (0, 16, 33, 50, 66 and 80%). The rolled specimen was examined for micro structure, and the volume fraction and mechanical properties were evaluated. In particular, the rolling specimen detected the elastic wave generated in tensile and investigated the relationship between the rolling degree and the dominant frequency. As the rolling degree increased, austenite decreased and martensite increased. The volume fraction of martensite more increased at lower temperatures, but increased rapidly at the rolling degree of 50% of all rolling temperature. Tensile strength increased rapidly with the increase of the rolling degree, and was larger at lower temperatures. The elongation decreased sharply to the rolling degree of 33%, but decreased gently thereafter. The dominant frequency highly appeared as the volume fraction of martensite increased, but the dominant frequency was higher at the low temperature rolling temperature. A similar trend was also observed in the relationship between tensile strength and dominant frequency.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.783-789
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• 2022

In this study, STS316L rolled at five rolling degrees were treated with two types of subzero temperatures for 10, 30, and 60 minutes, respectively, and the dominant frequencies of elastic waves was investigated. The dominant frequency was higher as the subzero temperature was lower and the subzero treatment time was longer at each rolling degree. On the other hand, the dominant frequency was higher as the elongation decreased. In the time-frequency analysis for subzero temperature and time of the specimen with a rolling degree of 33%, the dominant frequency was higher at a subzero temperature of -196℃ than -50℃ regardless of subzero treatment time.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.150-154
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• 1987

A new mixed approximation method is proposed for the model reduction of high order linear and time-invariant dynamic systems. This method makes allowance for stability and feature retention simultaneously. After defining dominant frequency range which affects relative stability of systems, a part of denominator is obtained using the energy dispersion method and tests are obtained using dominant frequency response matching method. The proposed method reflects the characteristic of the original system more faithfully and guarantees absolute stability of the reduction model.

• The Korean Journal of Ecology
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• v.20 no.6
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• pp.423-438
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• 1997

The structure and variation of the mating call in Rana nigromaculata was studied in a population at Da-rak, Chong-won, Chung-buk (36$\circ$ 37' latitude, 127$\circ$ 21' longitude) in Korea. The mating call consists of 3 to 8 pulse groups divided by clear silent intervals. Each pulse group is also composed of fine pulses. Temperature and body size affect the temporal and spectral characteristics of the mating call. Pulse, pulse group repetition rate and dominant frequency rise with increasing temperature, whereas pulse grouprepetition rate and dominant frequency decrease with increasing body size. A playback experiment was designed to establish the effect of a potential intruder on male calling. During the stimulus periods, resident males markedly decreased the pulse repetition rate, and icreased the rate of pulse groups, dominant frequency, and the number of call groups. This results indicate that this species responds in a graded fashion when interacting with other individuals.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.311-318
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• 2013

This paper deals with a noise reduction algorithm which uses the binary masking in the time-frequency domain. To improve speech intelligibility in noise, noise-masked speech is decomposed into time-frequency units and mask "0" is assigned to masker-dominant region removing time-frequency units where noise is dominant compared to speech. In the previous research, Gaussian mixture models were used to classify the speech-dominant region and noise-dominant region which correspond to mask "1" and mask "0", respectively. In each frequency band, data were collected and trained to build the Gaussian mixture models and detection procedure is performed to the test data where each time-frequency unit belongs to speech-dominant region or noise-dominant region. In this paper, we consider the correlation of masks in the frequency domain and propose a post-processing method which exploits the Viterbi algorithm.

• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.149-153
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• 1999

Frequency and temperature dependence of magnetic loss has been investigated in Mn-Zn ferrites containing the sesistive temary compounds of $SiO_2-CaO-V_2O_5$. The Mn-Zn ferrite with the composition of $MnO:ZnO:Fe_2O_3=36:11:53$(by mol %) are prepared by self-propagating high-temperature synthesis. From the results of frequency dependence of core loss, it has been found that the hysteresis loss is dominant at low frequency and the eddy current loss becomes more dominant as the frequency increases. With the addition of resistive compound, the frequency dependence of core loss, it has been found that the hysteresis loss is dominant at low frequency and the eddy current loss becomes more dominant as the frequency increases. With the addition of resistive compound, the frequency region where the hysteresis loss is dominant becomes wide. The core-loss minimum occurs at about 4$0^{\circ}C$ in the specimens with the additive because of the reduction in eddy current loss.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1055-1063
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• 2013

CTL cell that is one of the standard electromagnetic generation equipment can measure the characteristic of the electromagnetic susceptibility and the electromagnetic interference. In case of being input the same magnitude signal with the phase difference of 0o or the phase difference of 180o at two input ports of CTL cell to be the fundamental resonant frequency(TE011) of 2.20GHz, the characteristics of the electric field and the magnetic field at the uniform area were measured. And, it measured the electric field characteristic due to the variation of the input power, the test position and the input frequency under the dominant E-field and the dominant H-field of CTL cell. Using these mesuremed data, it examined the operation characteristic and the available frequency band of CTL cell.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.3
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• pp.206-211
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• 2007

The sciaenid species, which has swimbladder, generates sounds by vibrating in its length wards when spawning or getting stimulus from something else. This research analyzed on sound frequency characteristics relatives to their swimbladder length of three sciaenid species, yellow croaker(Larimichthys polyactis), brown croaker(Miichthys miiuy), and white flower croaker(Nibea albiflora). As results, the dominant frequency for yellow croaker ranged over 38.08 to 141.60Hz in wide frequency band, and the averaged pulse duration expressed in $280.3{\pm}156.0ms$. For brown croaker, the dominant frequency ranged in 49.80 to 59.57Hz, and the averaged pulse duration was $129.1{\pm}36.9ms$. Moreover, the dominant frequency of white flower croaker ranged in 73.24 to 86.91Hz, and the averaged pulse duration was $88.0{\pm}15.9ms$, it has shorter pulse duration than any two species. Therefore, the dominant frequency relatives to swimbladder length of sciaenidae showed that it had widely resonant characteristics and long pulse duration as in shorter swimbladder length. Additionally, for white flower croaker, we could confirm their behavior and sounds in response to production of recorded sounds using underwater speaker.