• Journal of the Korean Society of Visualization
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• v.2 no.2
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• pp.58-65
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• 2004

The purpose of this visualization study is to investigate the effect of reduced frequency qualitatively by examining wake patterns for dragonfly flight motion. Dragonflies have two pairs of wing (a forewing and hindwing) and flight is achieved by a pitching and plunging, so it makes a separation over the wings. The separation affects the wake pattern and changed wake pattern has an influence on lift, drag, and propulsion. This experiment was conducted by using a smoke wire technique and a camera fixed above the test section used to take a photograph of the wake. An electronic device is mounted below the test section to find the exact mean positional angle of the wing. The reduced frequency in the experiment is 0.15, 0.3 and 0.45. Results show that reduced frequency is closely related to the wake pattern that determines flight efficiency.

• Macromolecular Research
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• v.15 no.5
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• pp.396-402
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• 2007

The dielectric properties and various pattern-forming states of dual-frequency material in a nematic phase, as well as its mixture containing low concentrations of reactive monomers, are reported. The dielectric relaxation behaviors of nematic MLC 2048 are presented and compared to its mixture containing both mesogenic and nonmesogenic reactive monomers. The sign-inversion frequency of the dielectric anisotropy was significantly shifted on the addition of small amounts of the reactive monomers. However, all three mixtures used in this study essentially exhibited the same field-induced instabilities at different frequencies and voltage domains of the applied electric field. A broad band of modulated states were found to exist above a critical voltage and within a voltage dependent frequency band in the vicinity of the sign-inversion frequency, $f_I$, of the dielectric anisotropy. As the $f_I$ of the mixtures shifted, so did the bands of the modulated state of the different mixtures and the temperatures, which were well matched with the measured $f_I$ value.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.413-420
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• 1997

In this paper, we analyzed the contraction patterns of active elbow muscles during isometric, concentric and eccentric contraction. The analysis parameters consist of frequency domain parameters (mean frequency, median frequency, peak frequency, peak power, skewness, kurtosis) and time domain paraseters (zero crossing, positive maxima, integrated EMG). The results of this study were as follows; The BR/BB of isometric contraction appeared to be Venter as the elbow joint was more extended. The BR /BB during concentric and eccentric contraction tended to increase with more extension of the elbow joint angle, but there was no significant difference between concentric and eccentric contraction. Further, the EMG power spectrum due to the type of contraction were different betwen eccentric and concentric contraction. According to the results, it was found that the activation pattern in elbow flexor muscles was different during three different muscle contraction pattern. Therefore, elbow flexor muscles should not be considered a single functioning unit. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness kurtosis can be useful parameters in functional recognition for prosthesis control purpose.

• The Journal of the Korean dental association
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• v.46 no.4
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• pp.232-242
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• 2008

관절잡음의 발생은 측두하악 관절의 구조적, 기능적 이상의 징후로 여겨져왔다. 이러한 관절잡음을 평가하는데 electrovibratography가 비침습적이고 신뢰할만한 방법으로 제시되어 왔으며 이를 통해 관절잡음의 진동수와 진폭 및 전체 에너지 양상을 숫자화하고 도식화 하는 것이 가능하게 되었다. 기존의 연구에서 여러 가지 관절잡음의 양적, 질적 분석이 시도되어 왔다. 이번 연구의 목적은 관절 잡음이 도식화되어 나타나는 frequency spectrum pattern을 integral>300Hz/<300Hz ratio와 함께 분석하는 것이다. 본 실험에서는 Joint Vibration AnalysisTM를 사용하여 측두하악 관절 장애의 증상이 없는 10명의 대조군과 관절 잡음과 동통이 있으나 개구제한을 보이지 않는 정복성 관절원판 변위의 범주에 있는 20명의 실험군에서 관절진동을 분석하였으며 관절진동 기록 시에 Jaw tracker를 함께 사용하여 개폐구시 관절잡음 발생의 위치를 감별하고 치아접촉음을 배제하여 관절잡음을 분석하였다. 그 후 실험군을 frequency spectrum pattern에 따라 4가지 하위 그룹으로 나누어 분석하였다. 실험 결과 실험군과 대조군의 하위 그룹 1에서 유사한 frequency spectrum pattern과 ratio범위를 보였으며 실험군의 하위 그룹 2,3,4 에서는 더 불규칙한 에너지 양상을 보이는 frequency spectrum pattern과 더 큰 ratio가 관찰 되었다. 이번 연구를 통해 Joint Vibration AnalysisTM가 악관절 진동의 특성을 감별하는데 유용함을 알 수 있었고 Joint Vibration AnalysisTM를 이용한 지속적인 진동 분석이 환자 교육뿐 아니라 성공적인 턱관절 기능이상의 진단과 치료에 유용할 것으로 사료된다.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.9-12
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• 2002

The problem of sub-Nyquist nonuniform sampling for the perfect reconstruction of signals with time-varying spectral contents is studied. The signals are assumed to have a known instantaneous bandwidth in time-frequency domain. As the function of time, the nonuniform sampling pattern of a given signal, that is, the instantaneous sampling frequency is determined by the observation of instantaneous bandwidth based on time-frequency analysis. The proposed sampling pattern guarantees the perfect reconstruction of nonuniform sampled signals under Nyquist-sampling rate in average.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.6
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• pp.1069-1078
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• 2001

Pattern grading is a technique used to increase or decrease the size of a garment pattern according to the measurements in a given size chart. The original pattern is graded and laid out for cutting before mass production. This study tried to classify body types for pattern grading of jacket by applying a concept of "drop"defined as the difference between chest girth and waist girth and the difference between hip girth and waist girth for pants. Data were collected through the stratified sampling method. 138 subjects were selected out of 1,290 subjects of our sample population. Findings were as follows : 1) For pattern grading of jacket, the cell with the chest girth of 96cm and the waist girth of 87cm had the highest frequency rate and body type was 87H type and the coverage of this type was 9.52%. Then, the size specification 87-96 was the center of distribution. H type had seven ones such as 72H, 75H, 78H, 81H, 84H. 87H and 90H. H type had 33 observations and frequency ratio of 26.19%. Same types could be graded up and down from the reference size for the age group. And this reference size became to the starting point for developing the grading system. 2) For pattern grading of pants, fatty types, H10 type had six ones such as 80H10. 82H10, 84H10, 86H10, 88H10 and 90H10. H10 type had 28 observations and frequency ratio of 20.29%. H6 type had 6 ones such as 84H6, 86H6, 88H6, 90H6. 92H6 and 94H6. H6 type had 27 observations and frequency ratio of 19.57%. If lower body types were classified as same ones, these types could be graded up and down proportionately.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.3
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• pp.94-99
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• 2022

The discovery of biomarkers related to pattern identification (PI), the core diagnostic theory of Korean medicine (KM), is one of the methods that can provide objective and reliable evidence by applying PI to clinical practice. In this study, 40 diabetic patients and 41 healthy control subjects recruited from the Korean medicine clinic were examined to determine the human electrical response related to the deficiency pattern, a representative pattern of diabetes. Qi-Blood-Yin-Yang deficiency pattern scores, which are representative deficiency patterns for diabetes mellitus, were obtained through a questionnaire with verified reliability and validity, and the human electrical response was measured non-invasively using a bioimpedance meter. In ANCOVA analysis using gender as a covariate, the 5 kHz frequency resistance and 5-250 kHz frequency reactance were significantly lower in the diabetic group than in non-diabetic control group. In addition, the multiple regression analysis showed a positive correlation (R2=0.11~0.19) between the Yang deficiency pattern score and resistance value for the diabetic group; the correlation was higher at higher frequencies of 50kHz (R2=0.18) and 250kHz (R2=0.19) compared to 5kHz(R2=0.11). In contrast, there was no such significant association in the control group. It implies that bioimpedance resistance measured at finite frequencies may be useful in predicting Yang deficiency, which is closely related to diabetic complications by reflecting the decrease in body water content and metabolism. In the future, large-scale planned clinical studies will be needed to identify biomarkers associated with different types of PI in diabetes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.487-496
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• 2008

The purpose of this study is to investigate clinical frequency and priority of five pattern identification settled by Korean Standard Differentiation of the Symptoms and Sign for Stroke. The present study was done over 177 hospitalized patient with stroke in the Daejeon University Oriental Medical Hospital in the period of November 2006 to July 2007. Stroke patients had been interviewed by residents and specialists who studied standard operation procedures in Fundamental study for Standardization and Objectification of Differentiation and Pattern Identification of Syndrome of Oriental Medicine for Stroke. In Heat-transformation pattern group, men showed significantly high frequency and in Deficiency of Gi pattern group, women showed significantly high frequency. In Heat-transformation pattern group, the indicators such as 'aversion to heat during fever', 'flushed face', 'full and rapid pulse', 'dryness of the eyes, 'yellow coating of the tongue', 'feverishness of the limbs', 'dryness of the eyes' showed significantly high frequency. In Dampphlegm syndrome group, the indicators such as 'white coating of the tongue', 'yellowish face', 'thick coating of the tongue', 'wheezing in the throat with sputum', 'swollen tongue', 'slippery pulse' showed significantly high frequency. In Deficiency of Gi pattern group, the indicators such as 'pale tongue', 'lassitude', 'pale face', 'weakness pulse' showed significantly high frequency. In Deficiency of Eum group, the indicators such as 'short and rapid pulse', 'mirror-like tongue' showed significantly high frequency. For more sensitive Korean Standard Differentiation of the Symptoms and Signs for Stroke, Large scale study is to be done, giving weight on the important indicators.

• Explosives and Blasting
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• v.42 no.1
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• pp.12-22
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• 2024

In this study, the vibration characteristics according to the detonation pattern between rows in the blasting site were investigated by analyzing the vibration waveform, vibration velocity, and dominant frequency. As a result, it was found that the vibration waveform was changed according to the detonation pattern between rows in the blasting zone, and both the vibration velocity and dominant frequency was showed different condition.

• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.554-561
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• 2003

Results of the numerical simulation and experimental data analysis for identification of mode cutoff frequency and estimation of sound speed of seabed from the spectrum of acoustic signal received at fixed source-receiver range are presented. Model simulations for Pekeris waveguide show that the frequency-dependent propagation loss and interference pattern are closely related to mode cutoff frequencies and it could be possible to the identify them from the changes of interference pattern. The concept considered at numerical simulations is applied to signals acquired at sea test. Cutoff frequency and sound speed of seabed are estimated from the interference pattern of measured signal. Propagation loss predicted using the estimated sound speed of seabed as model input parameter shows similar estimation result compared to propagation loss derived from measured data.