• 한국항행학회논문지
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• 제14권4호
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• pp.562-570
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• 2010

뉴런에서 외부 자극을 받아 전위가 활성화되어 축삭을 따라 전도되는 현상은 전기적인 반응형태와 동일하다. 그러므로 본 논문에서는 전기회로의 개념을 도입하여 이러한 흥분전도현상을 해석하고자 하였다. 우선 축삭의 복잡한 전기적인 현상을 해석한 후 그 다음에 현실적으로 합리적이라 할 수 있는 가정 하에 단순화시킨 회로를 구성하였다. 전기공학적인 이론과 수학적인 개념을 도입하여 이 회로를 이용한 흥분전위의 전도현상을 유도하였다. 이 결과를 검증하기 위해 그동안 일반적으로 제시되었던 인체의 생리적, 전기적으로 대표할 수 있는 값들을 이용하여 어느 한 부위의 전위를 계산한 후 이것이 인근의 세포를 흥분시켜 다시 전도되는 현상을 확인하였다.

• 한국정보통신학회논문지
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• 제14권12호
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• pp.2827-2835
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• 2010

임계치 이하의 자극이 주어지면 흥분막은 어떤 특이한 반응을 나타내지 않으나 어느 정도 이상이 되면 아주 다른 양상을 띄게 된다. 흥분막에는 이러한 특성이 있다는 것이 진작부터 알려져 있었고, 일부 연구자들이 이러한 현상을 전기적인 회로를 이용하여 정량적으로 해석하려 노력하였으나 그것은 임계치 이하의 경우에 대한 것에 불과하다. 특히 임계치 이상의 자극에 대한 반응을 정량적으로 연구한 경우는 극히 드물다. 그런데 전기회로와 생체는 비슷한 점도 있지만 다른 면도 많아서 그대로 이를 적용하기에는 무리가 있다. 이러한 이유로 인하여 본 논문에서는 생체막이 임계치 이상의 자극을 받았을 때에 어떠한 현상을 나타내는가를 전기적인 관점에서 정량적으로 연구하였다

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.55-60
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• 2001

RF MEMS is an exciting emerging technology that has great potential to develop TOC (Transceiver-on-Chip). Applications of the RF MEMS to wireless communications systems are presented. The ability of the RF MEMS technology to enhance the performance and to reduce the size of passive components, in particular, switches, inductors, and tunable capacitors, is addressed. A number of potential wireless system opportunities for the TOC are awaiting the maturation of the RF MEMS technology.

• 대한조선학회지
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• 제23권2호
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• pp.21-26
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• 1986

An analysis is made of hydrodynamic forces acting horizontally on a two-dimensional cylinder, when it is exposed to incident waves and consequently undergoes a swaying motion in shallow water. Applying the method of matched asymptotic expansions the added mass, wave damping and the wave exciting force are obtained in terms of the difference in potential across the cylinder in a simple manner. The potential jump is related to the so-called blockage coefficient which is determined purely from geometry. It is found that the wave damping coefficient can not exceed the blockage coefficient.

• 한국해양공학회지
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• 제11권2호
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• pp.91-99
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• 1997

This paper presents theoretical formulations and numerical computations for predicting first-and second-order hydrodynamic force on a ship advvancing in waves. The theoretical formulation leads to linearized radiation and diffration problems solving the three-dimensional Green function integral equations over the mean wetted body surface. Green function representing a translating and pulsating source potantial for infinite water depth is used. In order to solve integral equations for three dimentional flows using Green function efficiently, the Hoff's method is adopted for numerical calculation of the Green function. Based on the first-order solution, the mean seconder-order forces and moments are obtained by directly integrating second-order pressure over the mean wetted body surface. The calculated items are carried out for analyzing the seakeeping characteristics of Series 60. The calculated items are hydrodynamic coefficients, wave exciting forces, frequency response functions and addd resistance in waves.

• 한국음향학회지
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• 제2권1호
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• pp.48-58
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• 1983

The transient sound radiation from the impact between a steel ball and a thick plate is analyzed theoretically and compared with experiment results. The derivation process itself is difficult to analyze sound radiation characteristics theoretically for a thick plate with some resonances but may be investigated from measured data. During mechanical impacts, arbitrary driving point importance for an elastic system enables to predict by using mechanical importance method. In order to obtain approximate solution for an impact model testing, the surface Helmholtz integral formulation based on the integral expression for pressure in the field in terms of surface pressure and normal velocity is used as a basis. A simple expression is developed for an impulsive response function, which is time dependent velocity potential and pressure for an impact may then be computed by a convolution of exciting force. In estimating of elastic-acoustical correlation problems, mechanical inertance, overall transfer function and radiation resistance obtained by signal processing techniques are used. The usefulness is confirmed by applying these methods prediction of arbitray driving pint inertance, radiated sound pressure and exciting force.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.96-101
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• 2004

When the wind blows hard, most waves are breaking in sea. Breaking waves occur, exceeding limitation of wave steepness(wave height/wave length=l/7). Because a wave of single angular frequency couldn't generate the breaking phenomena at two dimensional ocean engineering basin, the breaking wave can be generated by the superposition of waves with various angular frequencies. We research how are the particle kinematics in the breaking wave and the magnitude of the breaking wave exciting force. We compare the force in a regular wave which has same specifications(wave height, period and length) as the breaking wave. Also the experimental results of wave exciting force and particle velocity are investigated by comparison on the analytic results using the potential theory.

• 대한조선학회지
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• 제19권1호
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• pp.23-32
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• 1982

Herein the motion of a freely-floating sphere in a water of finite depth is analysed within the framework of a linear potential theory. A velocity potential describing fluid motion is generated by distributing pulsating sources and dipoles on the immersed surface of the sphere, without introducing an inner flow model. The potential becomes the solution of an integral equation of Fredholm's second type. In the light of the vertical axisymmetry of the flow, surface integrals reduce to line integrals, which are approximated by summation of the products of the integrand and the length of segments along the contour. Following this computational scheme the diffraction potential and the radiation potential are determined from the same algorithm of solving a set of simultaneous linear equations. Upon knowing values of the potentials hydrodynamic forces such as added mass, hydrodynamic damping and wave exciting forces are evaluated by the integrating pressure over the immersed surface of the sphere. It is found in the case of finite water depth that the hydrodynamic forces are much different from the corresponding ones in deep water. Accordingly motion response of the sphere in a water of finite depth displays a particular behavior both in a amplitude and phase.

• Asia pacific journal of information systems
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• 제16권2호
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• pp.123-141
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• 2006

Mobile games have emerged as the most innovative entertainment technology, adding new revenue streams, taking advantage of the potential of wireless applications and service offerings. Mobile games, as well as PC games, Video games and online games, offer a unique value for users in providing an exciting digital experience in virtual worlds. The overall trend for mobile games is towards bigger, more colorful, more involving and exciting contents, which might build upon the developing capabilities of mobile phones and networks, in order to bring new styles, concepts and experiences of game play to the users. In this paper, we investigate the factors influencing the usage and acceptance of the mobile games, based on the extended version of the Technology Acceptance Model (TAM). Based on data collected from online survey, we show that perceived usefulness, ease of use are the major determinants for mobile game users to play games. Four factors, including ease of use, self-expressiveness, visibility, and innovativeness are empirically shown to determine the level of perceived usefulness; additionally, innovativeness and facilitating conditions are shown to directly affect ease of use. Based upon the statistical results, some useful guidelines for game development and market penetration strategies are also provided.

• 한국해양공학회지
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• 제21권1호
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• pp.18-24
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• 2007

When the wind blows strong, most waves are breaking at sea. Breaking waves occur by exceeding the limitation of wave steepness (wave height/wave length = 1/7). Because a wave of single angular frequency couldn't generate the breaking phenomena at a two-dimensional ocean engineering basin, the breaking wave can be generated by the superposition of waves with various angular frequencies based on dispersion relation. This study investigates the particle kinematics in the breaking wave and the magnitude of the breaking wave exciting force at the breaking point and breaking region. We compare the regular wave load in a regular wave, which has same specifications (wave height, period and length), with the breaking waveload. Also, the experimental results of wave exciting force and particle velocity are investigated, by comparison with the analytic results using the potential theory.