• 한국해양공학회지
• /
• 제15권2호
• /
• pp.22-32
• /
• 2001

The numerical investigation of obliquely incident wave interactions with fully submerged dual buoy/porous-membrane floating breakwaters placed in parallel with spacing is studied based on linear potential theory and Darcy's law. The numerical solutions are obtained by using a discrete-membrane dynamic model and second-kind modified Bessel function distribution over the entire boundaries of fluid regions. First, numerical solutions for an idealized dual submerged system without buoys are obtained. Second, a more practical dual submerged system with membrane tension provided by buoys at its tops is investigated by the multi-domain boundary element method particularly devised for dual buoy/porous-membrane problems with gaps. The velocity potentials of wave motion are coupled with porous-membrane deformation, and solved simultaneously since the boundary condition on porous-membrane is not known in advance. The effects of varying permeability on membranes and wave characteristics are discussed for the optimum design parameters of systems previously studied. The inclusion of permeability on membrane eliminates the resonances that aggravate the breakwater performance. The system is highly efficient when waves generated by the buoys and membranes were mutually canceled and its energy at resonance frequency dissipates through fine pores on membranes.

• 한국전자파학회논문지
• /
• 제13권1호
• /
• pp.60-67
• /
• 2002

본 논문에서는 발진부 귀환경로에 스위칭소자를 이용하여 최소의 소자을 사용한 소형화된 새로운 방식의 이동통신 단말기용 듀얼대역 VCO(Voltage Control Oscillator)를 제안하였다. VCO에 공진기의 Q(Quality factor)값을 정확히 모델링하기 위하여 공진기를 등가 모델하고, 이론 수치 해석하여 최적의 공진기를 설계하였다. 본 논문에서 제안된 방식을 적용하여 GSM(Global System for Mobile), DCS(Digital Cordless System) 대역의 동작 주파수를 갖는 듀얼대역 전압제어 발진기를 설계하였으며, 논문의 객관성을 입증하기 위해 제작 및 실험을 통하여 새로 제안된 방식의 듀얼대역 전압제어 발진기의 실용화가 가능함을 확인하였고, 앞으로 차세대 이동통신 기기의 고주파 부품 등에 응용될 수 있을 것이다.

• 정보화정책
• /
• 제26권2호
• /
• pp.62-80
• /
• 2019

본 연구의 목적은 정보침해 경험이 정보보호 활동에 직관적으로 미치는 영향과 정보보호 인식을 통해 분석적으로 미치는 영향을 이중 프로세스 이론(Dual Process Theory)을 통해 분석하는데 있다. 이를 위해 Baron & Kenny 매개 회귀분석을 사용하였으며 그 분석결과는 다음과 같다. 첫째, 정보침해 경험은 정보보호 활동에 긍정적인 영향을 미치는 것으로 분석되었다. 둘째, 정보보호 인식은 정보침해 경험과 정보보호 활동 간의 관계를 매개하는 것으로 분석되었다. 셋째, 정보침해 경험이 정보보호 활동에 직접적으로 주는 영향과 인식을 매개하여 주는 간접적 영향의 효과는 모두 정(+)의 효과를 주는 것으로 분석되었다. 또한 정보침해 경험이 정보보호 활동에 주는 직접적 영향은 인식을 매개하여 정보보호 활동에 주는 간접적 영향에 비해 상대적으로 큰 것으로 분석되었다. 해당 분석결과를 바탕으로 정보보안 활동이 제고 될 수 있도록 하는 주기적 정보보안 교육 및 캠페인 정책이 필요함을 제언하였다.

• Advances in aircraft and spacecraft science
• /
• 제4권6호
• /
• pp.711-727
• /
• 2017

This article is concerned with a two-dimensional problem of micropolar generalized thermoelasticity for a half-space whose surface is traction-free and the conductive temperature at the surface of the half-space is known. Theory of two-temperature generalized thermoelasticity with phase lags using the normal mode analysis is used to solve the present problem. The formulas of conductive and mechanical temperatures, displacement, micro-rotation, stresses and couple stresses are obtained. The considered quantities are illustrated graphically and their behaviors are discussed with suitable comparisons. The present results are compared with those obtained according to one temperature theory. It is concluded that both conductive heat wave and thermodynamical heat wave should be separated. The two-temperature theory describes the behavior of particles of elastic body more real than one-temperature theory.

• 대한가정학회지
• /
• 제39권9호
• /
• pp.137-152
• /
• 2001

On the basis of the equity theory, as the couple perceives their relationship is equitable, they tend to make decisions jointly and are satisfied with their family lives. Therefore this study is aimed to identify the relationship among perception of equity, decision-making styles and family life satisfaction in dual-career couples. As a result of analyzing the cause-effect relationship, it shows that many socioeconomic$.$psychological variables have direct indirect impact on family life satisfaction through medium factor, so this study proves the application of the cause-effect modes. However the influence of the perception of equity of wives were higher than husbands.

• 전기학회논문지
• /
• 제60권9호
• /
• pp.1741-1747
• /
• 2011

Though various techniques have been studied as a way of adjusting parameters of PID controllers, no perfect method of determining parameters is available to date. This paper proposes a new method for enhancing performance of PID controllers by using the characteristics of dual-input describing function (DIDF). In other words, if nonlinear elements with two inputs (DIDF) are connected in series to the plant, the critical point (-1+j0) for Nyquist stability theory can be moved to a position arbitrarily selected on the complex plane by determining necessary coefficients of the DIDF appropriately. This makes the application of the existing conventional PID parameter tuning methods a lot easier, and stability and robustness of the system are improved simultaneously due to the DIDF inserted.

• 전자공학회논문지A
• /
• 제30A권10호
• /
• pp.1-11
• /
• 1993

A narrow-band dual TE$_{111}$ mode circular waveguide filter for Ku-Band satellite transponder was designed and manufactured based on a new model of the filter. We calculated the cavity size, pin polarizer depth and diameter, iris length and width, and used Bethe's Small Diffraction Theory and Chon's Correction Formular in order to obtain exact Result for each cavity. The designed dual model waveguide filter was manufactured with invar in order to maintain the thermal stability, and the filter performance was improved through the thermal test and vibration test to endure in the cosmic environment.

• 한국해양공학회지
• /
• 제19권2호
• /
• pp.19-28
• /
• 2005

The present paper outlines the numerical investigation of the incident wave interactions with fully submerged and floating dual double hull pontoon/vertical porous membrane breakwaters. Two dimensional five fluid-domains hydro-elastic formulation was carried out in the context of linear wave body interaction theory to study the wave interaction with the double hull of pontoon-membranes. The submerged circular pontoon is consisted of double hulls, which is filled with water in the void space between the outer structure and inner solid buoyant structure. Hydrodynamic characteristics of the proposed system with dual floating double-hull-pontoons filled with water have been studied numerically for the various incident waves. This study is a beginning stage research for the dual double hull porous pontoons/vertical porous membranes breakwaters which is ideally designed in order to suppress significantly the transmitted and reflected waves simultaneously.

• Steel and Composite Structures
• /
• 제35권3호
• /
• pp.343-351
• /
• 2020

The present research deals with the multi-dual-phase-lags thermoelasticity theory for thermoelastic behavior of transversely isotropic thermoelastic thin circular plate The Laplace and Hankel transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution are computed in the transformed domain with the radial distance and further determined in the physical domain using numerical inversion techniques. The effect of rotation and two temperature are depicted graphically on the resulting quantities.

• 대한수학회지
• /
• 제43권6호
• /
• pp.1339-1355
• /
• 2006

This paper develops in detail the differential geometry of ruled surfaces from two perspectives, and presents the underlying relations which unite them. Both scalar and dual curvature functions which define the shape of a ruled surface are derived. Explicit formulas are presented for the computation of these functions in both formulations of the differential geometry of ruled surfaces. Also presented is a detailed analysis of the ruled surface which characterizes the shape of a general ruled surface in the same way that osculating circle characterizes locally the shape of a non-null Lorentzian curve.