• 대한토목학회논문집
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• 제6권2호
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• pp.67-75
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• 1986

본 연구에서는 파랑의 에너지 및 에너지 수송과 관련된 변량들의 계산과 그 비선형효과의 분석을 능률적으로 수행하기 위하여 설계파에 대한 비선형 흐름함수파이론을 도입한다. 흐름함수파이론은 비대칭성 파형을 갖는 실측파와 이론적인 대칭 파형을 갖는 설계파. 두 경우 모두에 사용할 수 있는 이론으로 Dean에 의해 처음 창안되었다. 후에 Dalrymple이 특정한 파고의 조건과 0의 평균해수면 변위의 조건을 만족하도록 하는 두 라그란지 승수를 사용하여 기존의 수치계산 과정을 개량함으로써 수치계산이 좀 더 효율적으로 수행되도록 하였다. 그리고 흐름함수의 계수 (Stream function coeffiicient)들은 본 연구를 위해 개량한 Marquardt algorithm을 사용하여 수치계산된다. 본 연구의 결과로서 평균 위치에너지와 평균 운동에너지, 평균 전에너지의 비선형효과는$L^*/L_O$의 감소와 $H/H_B$의 증가에 한결같이 증가하여 흐름함수이론과 비교하여 선형파이론이 항상 과대평가된다. 군속도와 파장의 비선형효과는 $H/H_B$의 증가에 한결같이 증가하되 선형파이론이 항상 과소평가된다. 마지막으로 평균 전에너지 Flux의 비선형효과는 천해파(shallow-water waves)에 대해서는 선형파이론이 과대평가되고 심해파 (deep-water waves)에 대해서는 선행파이론이 과소평가되는 양면성을 지닌다.

• 대한조선학회지
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• 제5권2호
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• pp.35-44
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• 1968

The longitudinal cut method of experimental ship wave analysis, originally developed by J.N. Newman, is presented and various plausible sources of error are discussed. A further use of autocorrelation function and crosscorrelation function when two wave systems are superposed is indicated.

• 대한물리의학회지
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• 제4권3호
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• pp.201-207
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• 2009

Purpose：The purpose of this study was to investigate the effect of $\alpha$-wave music and art appreciation on hand function in stroke with hemiplegia. Methods：A total of 32 stroke with hemiplegia participated in this study experimental group(16 subjects) received $\alpha$-wave music and art appreciation with general neurologic therapy. Control group(16 subjects) received general neurologic therapy. All subjects were assessed for hand function(manual dexterity, power grip, pinch grip, two point discrimination(parm, finger), tactile sense(parm, finger) using a purdue pegboard, dynamometer, pinch gauge, two-point anethesiometer and semmes-weinstein monofilament wire. The data were analyzed using paired and independent t-test. Results：The results were as follows : 1. In the experimental group, manual dexterity were significantly increased between pre and post intervention(p<.05). 2. In the experimental group, tactile sesne in finger were sifnificantly increased between pre and post intervention(p<.05). Conclusion：The results of this study shows that $\alpha$-wave music and art appreciation affect the hand function of hemiplegic side with regard to manual dexterity and tactile sense.

• The Journal of Korean Physical Therapy
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• 제20권1호
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• pp.75-79
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• 2008

Purpose: The purpose of this study was to investigate the effect of $\alpha$-wave music and art appreciation on hand function. Methods: A total of 22 university students participated in this study (10 males and 12 females). Twelve subjects received $\alpha$-wave music and art appreciation. The other subjects received neither. All subjects were assessed for hand function (manual dexterity, power grip, pinch, lateral pinch, tactile sense) using a Purdue pegboard, dynamometer, pinch gauge, and Semmes-Weinstein monofilament wire. The data were analyzed using paired and independent t-tests. Results: The results were as follows: 1. In the experimental group, manual dexterity and tactile sense were significantly increased between pre- and post-intervention (p<0.05). Within the control group, manual dexterity and power grip were significantly increased between pre- and post-test (p<0.05). 2. With regard to dexterity and tactile sense, the experimental group experienced a significant post-intervention increase compared to the control group (p<0.05). There was no significant difference in power grip, pinch, or lateral pinch changes between the two groups (p>0.05). Conclusion: The results of this study show that $\alpha$-wave music and art appreciation affect hand function with regard to manual dexterity and tactile sense.

• 한국해안해양공학회지
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• 제6권1호
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• pp.88-93
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• 1994

유한수심에서의 불규칙파에 적용할 수 있는 파고의 확률분포함수를 2가지 해석적 방법으로 유도하였다. 첫번째 방법으로 새로이 유도된 확률분포함수는 Rayleigh 확률분포함수에 대한 직교 다항식을 유도함으로써 급수형태로 표시된다. 유도된 확률밀도함수를 비정규성이 강한 천해에서 측정한 파랑자료와 비교하였다. 확률밀도함수가 자료의 막대그래프와 잘 일치하였으나, 확률밀도함수가 급수로 표시되어 있기 때문에 파고가 큰 부분에서 음의 확률값이 된다. 비록 음의 확률값의 크기가 작다 하더라도 파고의 극치분포함수를 구하기에 부적절하다고 판단된다. 두번째 방법은 최대 엔트로피 법(maximum entropy method)을 적용하여 파고 분포와 매우 잘 일치하며, 극치파고분포와 파고의 통계적인 특성 등을 추정하는 데 매우 유용함을 알 수 있다. 그러나 최대 엔트로피 법을 사용했을 경우, 비정규분포 특성을 나타내는 변위의 분포함수와 파고의 분포함수 사이의 함수관계를 구할 수 없었다.

• 한국지진공학회논문집
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• 제23권3호
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• pp.191-199
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• 2019

To calculate proper seismic design load and seismic design category, the exact site class for construction site is required. At present, the average shear-wave velocity for multi-layer soil deposits is calculated by the sum of shear-wave velocities without considering of vertical relationship of the strata. In this study, the transfer function for the multi-layered soil deposits was reviewed on the basis of the wave propagation theory. Also, the transfer function was accurately verified by the finite element model and the eigenvalue analysis. Three methods for site period estimation were evaluated. The sum of shear-wave velocities underestimated the average shear-wave velocities of 526 strata with large deviations. The equation of Mexican code overestimated the average shear-wave velocities. The equation of Japanese code well estimated the average shear-wave velocities with small deviation.

• 호남수학학술지
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• 제37권4호
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• pp.411-421
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• 2015

This paper investigates the issue of analytic travelling wave solutions for some important coupled models of fractional order. Analytic travelling wave solutions of the considered model are found by means of the Q-function method. The results give us that the Q-function method is very simple, reliable and effective for searching analytic exact solutions of complex nonlinear partial differential equations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.950-953
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• 2006

The floor impact noise of concrete structures in apartments buildings is affected from the flexural wave propagation characteristics. Accordingly, the measurement of wave propagation characteristics is required for suggestion of efficient method to reduce the impact noise. The purpose of this article is to propose an experimental technique to measure dynamic properties of concrete structures. The method was proposed using the flexural wave propagation characteristics. Wave speeds, bending stiffness and their loss factors are estimated from which the vibration dissipation capabilities are investigated. Several different concrete beam structures were custom-built for measurement. The damping treatments using viscoelastic materials for reducing noise generation are also tested. The beam transfer function of the damped beam is predicted using the compressional damping model from which the mechanism of the vibration energy dissipation is investigated.

• Journal of Ship and Ocean Technology
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• 제4권1호
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• pp.28-36
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• 2000

Numerical simulation based on the superposition of ring waves generated by the linear periodic source distributions for the plunger type wave maker was accomplished. The characteristics of directional spreading function were investigated. Mirror images are also introduced to consider reflections of side-wall together with the reflection coefficient to account for the imperfect reflection from the real side wall in the long experimental towing tank. Unexpected spurious waves, resulting from the combined effect of finite breadth of segmented wave maker, wavelength and main wave maker, wavelength and main wave propagating direction, were observed in the line source method and also in the analysis of the directivity. The influence of spurious waves to the directional spreading function was also investigated.

• 천문학논총
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• 제22권4호
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• pp.113-132
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• 2007

On the framework of stochastic gravitational wave background(SGWB) by compact binary systems, we studied the strain spectra of SGWB produced by cosmological cataclysmic variables(CV). For this we reviewed the empirical properties of CVs by using newly published CV catalogue and calculated the cosmological densities of CVs considering the galaxy luminosity function and cosmic stellar birth rate function. Assuming the secular evolution of CVs, we calculated the time scale of CV gravitational wave(GW) radiation and derived formulae for the strain spectra of SGWB by cosmological CVs.